Why Study the Sun? What Is the Magic of Exploring the Sun When the Deep Space Age Comes?

On October 14, at Taiyuan Satellite Launch Center, China's first scientific and technological test satellite for solar exploration, Xihe, successfully lifted off with a long march-2 D carrier rocket, opening the way for flower growers to explore the sun. The name Xihe comes from the name of the sun goddess in ancient mythology, which contains the meaning of "imitating Xihe to control heavenly horses and aim to herd stars in the sky".

The process of human chasing the sun began from the era of totem worship. The primitive indigenous people once worshipped the sun as a God, and there are records about the sun in our own ancient books. The earliest sunspot record recognized in the world is in the annals of the five elements of the Han Dynasty: "at the end of March B in the first year of chengdi Heping, the sunrise is yellow and black, as big as money, and lives in the center of the sun". In the west, until 1610, Galileo, an Italian astronomer, saw sunspots with a telescope for the first time and found that sunspots were a very common phenomenon on the solar surface.

Until today, the pace of studying the sun has not stopped, still heading deep. Over the past decade, more and more achievements have been made in aerospace technology and deep space exploration. SpaceX has successfully recovered rockets. The blue origin of the Bezos family has sent its boss Bezos into space. Manned spaceflight has entered the commercialization stage. With the rapid development of aerospace technology, the technology of exploring Japan has also followed. Human beings have been chasing the sun. Why are people keen to study the sun? What are the current research results? What challenges and problems have you encountered on the road of chasing the sun?

Why study the sun?

The explanation we learned from the book is that the sun is a star with continuous nuclear fusion, resulting in continuous luminescence and heating. Due to the huge mass of the sun, other planets in the solar system rotate around it. The huge heat of the sun gives energy to the survival of life on earth. Under the gravity of the sun, the earth's autobiography and revolution give the diversity of biological life. The sun is closely related to the earth's ecological environment.

In the coronal layer on the surface of the sun, countless charged particles flow to the external radiation every day. These charged particle flows are also known as the solar wind. The earth is also within its scanning range. These particle flows are constantly attacking the earth at a speed of more than 500 km / s, interfering with the earth's magnetic field, damaging the structure of the earth's ionosphere and causing the interruption of radio communication.

These violent solar winds will have a great impact on human production and life:

1. The violent solar wind will have a destructive impact on all satellites around the earth and seriously interfere with the functional operation of electronic equipment inside the satellite.

2. The solar wind will affect the health of astronauts stationed on the space station.

3. Solar particles affect the electromagnetic signals on the ground of the near earth environment. Once hit by the solar storm, it will lead to power failure and network disconnection in some areas of the earth. All economic activities and life related to network and power in these areas will be suspended, resulting in huge economic losses.

The research on the sun will be able to understand the interaction between the solar wind, solar particles and the near earth environment, master the laws and characteristics of the solar wind, help the normal operation of space weather and spacecraft, and reduce or avoid the adverse impact on the near earth environment. From the earliest pioneer to the solar orbiter which is closer to the sun than mercury, a number of solar exploration missions have been carried out internationally, and the technologies and tools for exploring the sun have also changed in recent decades.

From telescopes to satellites

In addition to naked eye observation, the earliest tool to study the sun was the astronomical telescope. Through this tool, humans observed the operation laws of many planets. These telescopes are usually equipped with special filters to block out harmful parts of the sun's light. Professional astronomers use more advanced instruments to observe the solar surface and coronal layer, and need telescopes with different spectra. The research direction of radar observation is mainly solar radiation, acoustic interferometry and other technologies to study the interior of the sun. Satellites can detect the solar particle flow and radio frequency, and remotely observe the solar surface and space weather close to the earth.

With the in-depth development of aerospace technology, the use of satellite detectors to observe the sun is the most important tool and way. The benefits of solar exploration in space are not only closer, but also increase by orders of magnitude. Due to the existence of the earth's atmosphere, most of the light band radiation, such as most of the high-energy radiation such as ultraviolet and infrared, X-ray and gamma ray, is absorbed by the earth's atmosphere before reaching the ground. If the sun is observed on the ground, only visible light and limited radio radiation can be observed. Such a limited range is narrow for the study of the sun. The advantage of satellite is that it can completely separate from the influence of the earth's atmosphere and study the sun from various bands, so as to draw a complete solar image.

At present, the best solar probe in orbit is the Parker solar probe launched by NASA in 2018, which has created the record of the closest man-made object to the sun in history. Its set distance is about 6.1 million km, which means that the probe needs to enter the coronal layer. We know that the temperature of the coronal layer is particularly high (Parker needs to overcome the high temperature of 1400 ℃), It not only has to endure high temperature, but also maintain the normal operation of tens of degrees of internal room temperature, which is numbing in difficulty and technology.

From astronomical telescope to radar to satellite close-up observation, we are faced with technical challenges:

1. In order to ensure high accuracy analysis, a multi-layer safety redundancy system must be designed to ensure the reliability of data and avoid being affected by the high-energy electron flow of solar wind.

2. Like making solar detectors similar to or beyond Parker, when observing the sun at close range, it is necessary to prepare ultra-high temperature resistant materials. Both inside and outside the detector need the blessing of these special materials. It is extremely difficult to find and synthesize these superconducting high temperature resistant materials.

3. The magnetic pole of the sun will flip in a solar cycle (11 years), so it is necessary for satellites with long service life to fully observe the activities of the whole solar cycle.

4. Not only to prevent the invasion of solar storms, solar detectors also need to be designed and developed to prevent the interference and influence of other high-energy electric ions in space.

The ultra long flight in deep space is the peak of Aerospace Science and technology. Especially flying towards the ultra-high temperature furnace of the sun, we should not only solve the ultra-long-distance energy problems, complex temperature changing environment, solar storm... But also calmly deal with the crisis at any time in the long journey of hundreds of millions of kilometers. It can be said that every second of the distance is full of accidents and difficulties. Under such conditions, these solar detectors have brought great benefits to human research.

Day by day to the future

Space technology has developed since 1960, and scientists have begun to detect and study solar activities. At present, more than 70 solar observation satellites have been launched all over the world, mainly focusing on the observation and research of surface mass ejections such as sunspots, flares and corona. We know that modern solar research mainly focuses on comprehensive observation and near Earth Observation of solar structure, magnetic field and sunspots. Due to the space problem, I will only introduce some influential main achievements:

1. The Ulysses probe of the European Space Agency showed astronomers the change of the solar magnetic field. It was once thought that the change of the solar magnetic pole would be very rapid. Thanks to Ulysses' observation, it was found that this process is a gradual process, which may take about seven years to change.

2. The detector finds the law of sunspots. After the solar minimum period, the number of sunspots will gradually increase, form at the latitude of 35 degrees in the northern and southern hemispheres of the sun, reach the equator and finally disappear, and the bright spots of the corona will also move from the high dimension to the equator.

3. The solar terrestrial relationship observation platform, the world's first twin solar observation satellite launched by the United States, has carried out three-dimensional imaging of the sunspot outbreak, allowing scientists to study the surrounding environment of the sun and the impact of solar activities on the whole solar system in a three-dimensional way for the first time.

4. After the Parker solar probe was launched, it helped scientists find the source of the solar wind. The low-speed solar wind appeared near the coronal hole near the equator, with a speed of less than 450 kilometers per second; Near the solar polar region, the high-speed solar wind blows at a speed of more than 450 kilometers per second. The reason for the final ultra-high speed acceleration of the solar wind has also been found, and the rotation speed of the sun has also been found to be much faster than we thought, giving researchers a new perspective on the evolution of stars.

This is a relatively new and important achievement at present, and the future exploration of the sun will focus on the deployment of three-dimensional detection system to explore the sun in an all-round way. This three-dimensional exploration scheme is also proposed by our florists. For this three-dimensional detection system scheme, detectors will be deployed at five points on the ecliptic plane and the polar orbit in the future to realize "encircling" observation of the sun. The probe, especially the polar probe, needs five years to fly in place. The time given by NASA is to build an omni-directional three-dimensional detection system for the solar polar region around 2035.

Although there are many previous papers on the study of the sun, our research is based on the second-hand data of exploring the sun in other countries. It is difficult to make an impact on astronomy and lead solar research. The achievements of original innovation must be based on the development of spacecraft with its own solar exploration ability, and the deployment and planning of three-dimensional system for solar exploration will greatly change our position in the academic circle of solar research: the great change from follower to leader can be expected in the future.

The end result of the solar detector is to decompose and fall to the sun step by step after the energy is exhausted, and become a part of the cosmic dust. However, mankind's pursuit of the sun will never stop. The puzzles about the sun and the answers to the solar storm are the direction that mankind wants to conquer. Even if it is a slim hope, mankind will move forward with iron head until the moment when mankind dies.

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How to Avoid Light Pollution in the Use of Landscape Lamps
Urban landscape construction is an indispensable part of urban planning. The colorful garden landscape lights make the City show another beauty at night. However, there is often something hidden behind the beauty. This is not true. The lighting line of this beautiful garden landscape is too dazzling, which really makes the surrounding residents unable to adapt and unbearable.At present, many cities are bidding for garden landscape lighting planning based on the principles of high efficiency, energy saving, green and environmental protection, and avoiding light pollution has become an important evaluation content. This indicates that the concept of landscape lighting construction in Wuhan is changing: it is not "the brighter the more beautiful", but "bright" reasonably and carefully. The concept of "never night city", which was proud a few years ago, is no longer applicable.How to correctly use landscape lamps to decorate the night scene of the city, landscape lamp manufacturers feel that they must first do the following:1. To strengthen the management of urban construction, reduce and prevent urban light mattress dyeing, we should strengthen the management of urban construction. Firstly, the scope of use of decorative materials such as glass curtain wall should be controlled; Restricted to busy areas, traffic intersections and residential areas; Limit the installation area. Large glass curtain walls can be separated by partitions and straight bars in the middle; Adopt advanced glass with small reflection coefficient. The urban night scene lighting shall be scientifically and reasonably planned and designed in strict accordance with the lighting standards, and the light source, lamps and scenery scheme shall be reasonably selected; We should not only make the city bright and beautiful, but also meet the requirements of energy and environment, and build and implement the "green lighting project";2. The establishment and improvement of laws, regulations and relevant standards, and the trial process of many light pollution cases show that the current laws and regulations on light pollution are very insufficient.To control light pollution, there should be direct and specific provisions in laws and regulations. First, define what is light pollution in the environmental protection law; Formulate prevention and control measures for light pollution and build a supervision and management system; Implement subregional management and determine the quality standards and emission standards of light pollution in various regions; Environmental protection systems such as environmental impact assessment system and "three Simultaneities system" have been implemented in the field of light pollution. When formulating corresponding standards and specifications, it is recommended to refer to the relevant regulations and standards of the international lighting Commission (CIE) and developed countries.3. Strengthen publicity, education and technical research, and publicize the harm of light pollution to human and ecological environment, so as to attract more people's attention. Only with enough attention can we better implement the legislation, monitoring, planning, management and technical research of light pollution. Learn from foreign experience and measures to prevent and control light pollution, and establish the concept of ecology, environmental protection and energy saving.
What Can I Do About My 2004 Audi A4 Quattro Turbo?
turbocharging: Using an exhaust-driven turbine to drive a air compressor that compresses air into the cylinders and increases the power of the engine. This process produces more power because cars run on air more than they run on fuel. The more air the engine can take in, the bigger the bang is during the power stroke. How turbocharging works. 1. The hot exhaust gases leave the exhaust manifold in much the same manner as they usually do. But instead of going directly through the exhaust system and out of the car via the tailpipe, they first pass through a turbine, which is nothing but a fan that's set in motion by the velocity of the passing gases. 2. A shaft connects the fan to the compressor, which blows fresh, filtered air into the cylinders. (On a gasoline powered car, it takes the fuel/air mixture supplied by the carburetor and blows it into the cylinders.) 3.The excess and used exhaust fumes pass from the turbine to the exhaust system and continue on their way to the tailpipe and out into the air in their usual manner. 4. The more load on the engine, the hotter and faster are the exhaust fumes that turn the turbine. The faster they turn it, the more air the compressor sends to the engine and the faster the engine can go. This unique way of converting exhaust gas energy into mechanical power has a nice merry-go-round effect. * I have no comment on $500 for a tune-up. Good Luck.1. Why the similarity in the Equations of Motion for Rotational and Rectilinear Motion?The two sets of equations are mathematically equivalent.The angular velocity is defined as the rate of change of the angle: $$ omega=fracdthetadt$$ Which is analogous to the equation for rectilinear velocity $$v = fracdxdt$$ In the same way, the angular acceleration is defined as the rate of change of the angular velocity (so the second derivative of the angle): $$alpha=fracdomegadt=fracd^2thetadt^2$$ This is again analogous to the rectilinear case: $$a=fracdvdt=fracd^2xdt^2$$ So, it does not come as a surprise that the equations for both types of motion look similar.2. Device to allow camera to rotate on an axis that runs down the center of the lens?There are devices called Camera Rotators that might facilitate this. They are designed to let you rotate your tripod-mounted camera between portrait and landscape orientation, so most of them seem to be limited to 90 degrees of motion3. How do I protect my elderly parents at home?If you are tech savvy, put out a camera in the living space. Some of them could be hooked to motion detection triggers so that you may be able to even remotely monitor them and if anyone's in the house. Besides that, make sure they do not go hungry, eat and sleep on time, are not socially secluded and that they have some hobby. Make sure the bathroom floor is not slippery, stairs in the house are friction lined. Make sure the floor carpet is soft enough and that the areas are well lit4. Linear motion in the Euclidean plane?So, to build upon the answer by user21820, your book on linear algebra seems to state the situation the wrong way around, since scaling is not a geometric motion which preserves distance. The case of a linear transformation mapping into a lesser dimension is the extra case of adding a geometric projection (which is also a linear transformation). All linear transformations in 3 dimensional space can be represented geometrically by a rotation followed by a projection, a (optional) mirroring, a positive scaling, and a final rotation.5. Anyone know why i get muscle strains a lot?Neck muscles do not get much of a break from constant use. You may need a muscle relaxant while it heals, possibly even a collar to restrict motion. Then once it heals, careful strengthening. See your doctor and/or a physical therapist. Meanwhile, try not to turn your head. Turn your eyes, or your body to turn your view. Wear turtleneck sweaters to keep it more warm and relaxed, help it heal.6. What is quantum Brownian motion?A. To the extent that you think of Brownian motion as a random walk, the natural quantum extension is the quantum random walk. For a physics perspective, see Quantum random walks - an introductory overview, but you might prefer the more math-oriented exposition of Martin boundary theory of some quantum random walks and On algebraic and quantum random walks.We give a concise prescription of the concept of a quantum random walk (QRW), using the example of QRW on integers as paradigm. It briefly explains the notion of quantum coin system and the coin tossing map, and summarizes two emblematic properties of that walk, namely the quadratic enhancement of its diffusion rate due to quantum entanglement between the walker and the entropy increase without majorization effect of its probability distributions. We conclude with a group theoretical scheme of classification of various known QRW's.B. Concerning the relation between Wiener processes and quantum Brownian motion: A quantum version of the wavelet expansion of a Wiener process has been developed in A Levy-Cielsielski expansion for quantum Brownian motion and the construction of quantum Brownian bridges.Classical Brownian motion has a delightful wavelet expansion obtained by combining the Schauder system with a sequence of i.i.d. standard normals. Our main technical result is to obtain a quantum version of this expansion and so construct quantum Brownian motion in Fock space. Consequently, only the discrete skeleton provided by a "quantum random walk" is required to generate the continuous time process. Our result seems easier to establish than the classical one of Lvy-Cielsielski as we do not require logarithmic growth estimates on the squares of i.i.d. Gaussians, thanks to the nice action of annihilation operators on exponential vectors.C. Concerning a mathematical description of the physical phenomenon of Brownian motion: We are then concerned with the effect of an environment having a large (infinite) number of degrees of freedom on the dynamics of a particle with a few degrees of freedom. So we are seeking a quantum theory of friction, diffusion, and thermalization. The seminal paper here is the path integral theory of Caldeira and Leggett. The literature is very extensive, an older but still relevant review is Quantum Brownian Motion: The Functional Integral Approach.The quantum mechanical dynamics of a particle coupled to a heat bath is treated by functional integral methods and a generalization of the Feynman-Vernon influence functional is derived. The extended theory describes the time evolution of nonfactorizing initial states and of equilibrium correlation functions. The theory is illuminated through exactly solvable models.
The Usage Distinction Between Via and Pad When Protel Designs PCB
With regard to "via cover oil" and "via window opening" (the usage distinction between via and pad), many customers and design engineers often ask what this means when placing an order on the system, and which option should I choose in my document? This issue is explained as follows:        We often encounter such problems. The design is seriously non-standard, so we can't distinguish between pad and via. Sometimes the conductive hole is treated with pad attribute, and sometimes the keyhole is treated with via attribute. The design of via attribute and pad attribute is confused, resulting in wrong processing. This is also one of the problems that often complain. For circuit board production plants, when processing CAM data, Some film processing engineers will make mistakes because the customer's design documents are not standardized. They help the customer modify the documents, make the non-standard design right, and process the engineering data with their own experience, which leads to and contributes to the customer's non-standard design. Jieduobang hereby explains that what you did right last time does not mean that your documents are right! All engineers must pay attention to the design standards and specifications! Jieduobang will again strictly require all film processing engineers to maintain the status quo of customer documents as much as possible! Try to deal with it according to the design specifications and standards, not according to the so-called experience! Reflect the problems, so as to make a reference for all design engineers, improve the design quality and reduce the occurrence of problems!      This article mainly explains the conductive hole, keyhole, and the connection between Protel / pads / and Geber files. Conductive hole: via keyhole: pad is particularly prone to several problems: first, the mixed use of pad and via leads to problems. 1. When your file is pads or Protel, send it to the factory and ask for hole cover oil. Pay attention to it. You should carefully check your plug-in hole (PAD) Is it also useful for via? Otherwise, green oil will be applied to your plug-in hole, resulting in the inability to weld. The dispute points: the plug-in hole must be sprayed with tin. How can you cover the oil and how can I use it? Please check the documents when saying this, whether it is designed by pad or via!      When your document is pads or Protel, send the document to the factory, and the order requires via cover oil. Many customers use pad (plug-in hole) to represent the conductive hole, which leads to the opening of your conductive hole. Maybe what you want is via cover oil. At that time, the dispute may be that what I want is via cover oil. Why did you open the window, Please check your document design!Again, if you are via, press via. If you are pad, press pad! Because no one will know that you are a conductive hole, that is a plug-in hole, and via and pad are the only signs. Please be clear!      During the conversion process of via, problems are caused by non-standard design or unclear Gerber setting rules. When you send Gerber files, the factory can't distinguish which are through holes and which are keyholes. The only thing that can be identified is processing according to the file, which is helpful for welding layer and opening windows! Dispute point: you open the window for me now. I may cause a short circuit. Please check your file. The Gerber you sent out is a film file. The factory has no way to check whether you have a conductive hole or a keyhole. Please check the Gerber file to see if there is a welding aid layer. If there is any, open the window and cover the oil. III How to design the oil of the through hole cover in Protel or pads—— This is the most standard practice. If the design standard is, there will be no mistakes!      In the via attribute of Protel, there is a holding option. If it is checked, it must be oil capping, and all you transfer out are oil capping. In pads, the oil capping method of holes (via) is to be considered when transferring pads to files: when outputting soldermask, i.e. solder resist layer, just check the upper soldermask top - lower via, which represents all through-hole windows, If you don't check it, you can use the oil on the cover of the through hole. To sum up: pad is made according to pad, which is the plug-in hole. Via, you have two choices. If you provide the original file, you can choose it when placing an order. If you provide Gerber file, you must check whether the Gerber file meets your requirements!
Recording an Instructor While Filming Him From a Distance
Simple solution is for you to get all your audio from the PA mixer, and for when the instructor does his walkabout, just turn down or mute the signal to the speakers instead of muting the mic.This way you keep the same audio signal throughout for your recording, so no messing about with other microphonesOK, so here's my problem:I snuck myself into our Ninjutsu club's sporting event as the "photographer" - I have to video the event using my consumer Canon HF10 camcorder, and I'll have to produce a DVD of the event.Now, I have also videoed the previous event, and have detected a problem with recording the instructor's speech:The process is that the instructor demonstrates a technique, and then everyone practices the technique. The instructor then walks around, correcting mistakes. During the demos there is little problem: Everyone is (mostly) quite and the instructor wears a mike (connected to a little box worn at belt level) transmitting to an amplifying system (at least he did during the last event). So theres no problem there.However, when the instructor moves around he turns off the mike (because obviously he neednt be heard all across the mat). Its tough to run after him with the camera and the tripod, because people are spread all over the mat. Moreover, when he says the interesting things, people gather around him listening (and speaking). Also people around me go on training, which may get quite noisy. So I can't get a clear recording of the instructor and we miss the best parts, the corrections people could really learn from.So, what I need is some way to capture what hes saying while he's far from the camera. Any suggestions?Points to consider:This is Ninjutsu, so the instructor is moving around and is active, especially when doing the class demos. However, as hes the one doing the throws etc., and considering hes already wired to the amplifying systems mike, hes not overly active.Its a hobby. Im not going to be paid so expenses should be not too high.The result should be merged as a soundtrack to the video.The camera has no genlock.Im much more into it than the instructor is. Its a little like the cat and the bell, so it needs to be as little a hassle as possible.Thanks!·OTHER ANSWER:OK, so here's my problem:I snuck myself into our Ninjutsu club's sporting event as the "photographer" - I have to video the event using my consumer Canon HF10 camcorder, and I'll have to produce a DVD of the event.Now, I have also videoed the previous event, and have detected a problem with recording the instructor's speech:The process is that the instructor demonstrates a technique, and then everyone practices the technique. The instructor then walks around, correcting mistakes. During the demos there is little problem: Everyone is (mostly) quite and the instructor wears a mike (connected to a little box worn at belt level) transmitting to an amplifying system (at least he did during the last event). So theres no problem there.However, when the instructor moves around he turns off the mike (because obviously he neednt be heard all across the mat). Its tough to run after him with the camera and the tripod, because people are spread all over the mat. Moreover, when he says the interesting things, people gather around him listening (and speaking). Also people around me go on training, which may get quite noisy. So I can't get a clear recording of the instructor and we miss the best parts, the corrections people could really learn from.So, what I need is some way to capture what hes saying while he's far from the camera. Any suggestions?Points to consider:This is Ninjutsu, so the instructor is moving around and is active, especially when doing the class demos. However, as hes the one doing the throws etc., and considering hes already wired to the amplifying systems mike, hes not overly active.Its a hobby. Im not going to be paid so expenses should be not too high.The result should be merged as a soundtrack to the video.The camera has no genlock.Im much more into it than the instructor is. Its a little like the cat and the bell, so it needs to be as little a hassle as possible.Thanks!
Understand Rainbow,an Introduction to Rainbow
An Introduction to rainbowThe following have served as Masters of Magdalene College, Cambridge:Track listing of rainbowOriginal release7""Gravity's Rainbow" 2:37"The Bouncer" - 2:1512""Gravity's Rainbow" 2:37"Gravity's Rainbow" (Van She remix)"Gravity's Rainbow" (Nightmoves remix)"Gravity's Rainbow" (To My Boy remix)Re-releaseCD"Gravity's Rainbow" 2:36"Gravity's Rainbow" (Soulwax remix)7""Gravity's Rainbow" 2:36"Electrickery" produced by Erol AlkanEtched 7""Gravity's Rainbow" (Live in Glasgow)Service history of rainbowRoyal NavyRainbow was ordered as part of the Naval Defence Act of 1889. The vessel's keel was laid down by Palmers at Hebburn-On-Tyne in England on 30 December 1889. The cruiser was launched on 25 March 1891 and entered service in 1892, completing in January 1893.Rainbow served on the China Station in Hong Kong from 1895 to 1898 and in Malta from 1898 to 1899. She had an operating cost that was deemed excessive and between 1900 and 1909, saw very little service. Most of her operations at this time were closer to England. On 17 December 1901 she was commissioned at Devonport by Captain Thomas Young Greet for service in the cruiser squadron as an additional ship in home waters. She arrived back at Devonport from a tour of the Mediterranean with the squadron in April 1902, and took part in the fleet review held at Spithead on 16 August 1902 for the coronation of King Edward VII. Captain Charles Delabere Granville was appointed in command on 20 August 1902, and visited Souda Bay, Crete with other ships of the squadron for combined manoeuvres the following month. In October 1902 she was order back to Devonport for a refit. During the following years, she saw a severe reduction in fleet support due to her high operating cost, resulting in only minor modernization. Her crew rotation at this time was used as a training cycle. In 1904, the cruiser was restricted to harbour duty. In early 1909, the Admiralty ordered her decommissioned and placed on the inactive list.Royal Canadian NavyRainbow was presented to Canada in 1910, and was recommissioned HMCS Rainbow on 4 August. She and HMSNiobe were purchased from the Admiralty to be used as training ships at Royal Naval College of Canada in Halifax, Nova Scotia. During discussions on the type of cruisers to be sent to Canada, the Admiralty believed that the Apollo-class cruiser was the right choice. Canada paid $225,000 to acquire Rainbow, using outstanding money from the Marine and Fisheries Department. Before departing Great Britain, the ships required alterations to make them suitable for training. This required new heating systems, an up-to-date galley, the latest in Marconi wireless, the enlargement of the cadet gunroom and principal messes and the removal of the obsolete secondary armament.After commissioning, Rainbow was assigned to the west coast of Canada and was the first Canadian ship to sail around South America by the Strait of Magellan. After a 12-week passage of over 15,000 nautical miles (28,000km; 17,000mi) the cruiser arrived at Esquimalt, British Columbia on 7 November 1910. However, after commissioning, the status of the Canadian vessels and their ability to operate without direction from the Admiralty kept the new ships within coastal waters. This limited Rainbow to fisheries patrols until the matter was settled. In 1911, the cruiser had her 6-pounder guns removed and replaced with QF 12-pounder 12 cwt naval guns. Her service was quiet on the west coast, performing ceremonial duties, training and coastal fisheries patrol, notably apprehending the American fishing schooner Edrie in February 1913 for illegal fishing. When Niobe was laid up in 1913, her crew was sent west to fill out Rainbow's complement.In July 1914, Rainbow was called to Vancouver to assist with an international incident that was unfolding. Komagata Maru, a Japanese merchant ship filled with Sikh immigrants from India, challenged Canada's immigration law, designed to prevent immigration from South Asia. The ship's passengers were not permitted to disembark even though they were British subjects and the ship had sat in Vancouver harbour for two months. After the local authorities were rebuffed in their attempts to make the ship leave, Rainbow was ordered to intervene. After some discussion with the passengers, who had taken over the vessel, those aboard Komagata Maru agreed to leave Vancouver only when supplies for the ship were provided. Komagata Maru sailed from Vancouver on 23 July, escorted by Rainbow. Twenty of the passengers were killed upon returning to Budge Budge, India, after they resisted an attempt to forcibly return them to Punjab.When the First World War broke out, Rainbow was sent to cover the withdrawal of the British sloops, HMSShearwater and HMSAlgerine, which had been engaged protecting British citizens during civil unrest in Mexico. She was the largest armed ship the Allies had at the time in the western Pacific Ocean and was ordered to find and engage ships of the Imperial German Navy in the Pacific Ocean; in particular the light cruisers SMSLeipzig and SMSNurnberg. Rainbow never met either of these ships, although she missed Leipzig by only a day at San Francisco. The vessel remained the only source of protection for shipping in western North America until the arrival of the Japanese armoured cruiser Izumo. Following the destruction of the German Pacific Fleet at the Battle of the Falkland Islands in December 1914, the greatest threat to shipping in Pacific was considered to be armed German raiders and Rainbow was considered to be a match for all but the fastest. However, in 1915, her patrols were shortened due to the lack of a collier to refuel Rainbow while out on patrol.In early 1916, Rainbow was still patrolling the west coast of North America, performing reconnaissance on German shipping. On 23 April 1916, she seized the German-owned but American-flagged schooner Oregon and then followed that up by seizing the Mexican-flagged schooner Leonor on 2 May. The cruiser returned to Esquimalt with the prizes in tow on 30 May. In 1916 and early 1917, Rainbow was used to transport $140,000,000 in Russian gold bullion (valued in 1917 Canadian dollars), between Esquimalt and Vancouver. This money was placed in trust with Canada by the Russian government for protection due to the impending Russian revolution.The Royal Canadian Navy found that the cost of operating Rainbow was using up too much of the West Coast naval operations budget, and the crew of Rainbow were sorely needed on the Atlantic coast for the fight against the U-boats. Rainbow was decommissioned and deactivated on 8 May 1917, her crew sent east. On 5 July she was recommissioned in Esquimalt as a depot ship. She served in this capacity until 1 June 1920, when she was sold for scrap to a Seattle shipbroker.
Working Principle of Parallel Switching Power Supply
Figure 1-11-a is the simplest working principle diagram of parallel switching power supply, and figure 1-11-b is the waveform of output voltage of parallel switching power supply. In figure 1-11-a, UI is the working voltage of the switching power supply, l is the energy storage inductance, K is the control switch, and R is the load. In figure 1-11-b, UI is the input voltage of the switching power supply, uo is the output voltage of the switching power supply, up is the peak voltage of the switching power supply output, and UA is the average voltage of the switching power supply output.When the control switch K is turned on, the input power supply UI starts to energize the energy storage inductor L, the current flowing through the energy storage inductor L begins to increase, and the current also generates a magnetic field in the energy storage inductor; When the control switch K is turned from on to off, the energy storage inductor will generate back EMF, and the direction of the current generated by the back EMF is the same as that of the original current. Therefore, a high voltage will be generated on the load.During ton, the control switch K is turned on, and the voltage El at both ends of the energy storage filter inductance L is exactly equal to the input voltage UI, that is:El = LDI / dt = UI - during K-ON (1-35)By integrating the above formula, it can be obtained that the current flowing through the energy storage inductance L is:Where IL is the instantaneous value of the current flowing through the energy storage inductor L, t is the time variable, and I (0) is the initial current flowing through the energy storage inductor, that is, the current flowing through the energy storage inductor immediately before the switch K is turned on. Generally, when the duty cycle D is less than or equal to 0.5, I (0) = 0, so the maximum current ILM flowing through the energy storage inductance L can be obtained as follows:ILM = UI * ton / L - during k connection (d = 0.5) (1-37)Where ton is the time when the control switch K is turned on. When the control switch K in figure 1-11-a suddenly changes from on to off, the energy storage inductor L will release its stored energy (magnetic energy) through the back electromotive force. The back electromotive force generated by the energy storage inductor L is:The negative sign in the formula indicates that the polarity of the back EMF el is opposite to the symbol in formula (1-35), that is, the polarity of the back EMF of the inductance is exactly opposite when k is on and off. The first-order differential equation of formula (1-38) is solved as follows:In the formula, C is a constant. It is easy to calculate C by substituting the initial conditions into the above formula. Since the current IL flowing through the energy storage inductor L cannot change suddenly when the control switch K suddenly changes from on to off, I (ton ) is exactly equal to the maximum current ILM flowing through the energy storage inductor L, so formula (1-39) can be written as:When t is large, the value of the output voltage of the parallel switching power supply will be close to the input voltage UI, but this generally does not happen because the off time of the control switch K can not wait that long.As can be seen from equation (1-42), when the load r of parallel switching power supply is large or open circuit, the amplitude of output pulse voltage will be very high. Therefore, parallel switching power supply is often used in high voltage pulse generation circuit.
3 Simple Tips for Doubling Your Facebook Ad Results
Let's face it. Running Facebook ads is no easy task.Businesses around the world are all trying their hand at Facebook ads, only to figure out it's a bit more complicated than slapping some text on an image and calling it a day. Sound familiar?Do not worry. We've all been there at one point or another. It's important to remember that running Facebook ads is a constant battle. Luckily, there are a few proven methods you can use to immediately see more results from your efforts. If you apply and build off these tips, you will see your profits rise in no time.First off,A/B test your ad sets.Facebook ads are a guessing game. You can not know what is going to work well for your target audience without trying a ton of different options. So instead of publishing one ad set and hoping to hit home with your targeting, start A/B testing multiple ad sets!Before you launch your next campaign, build 5-10 different ad sets for the same ad, all equipped with different targeting, images, demographics, and more. I recommend that you run these ads under the "Engagement" goal to save a bit of cash.Once those ad sets have racked up about $10-$15 in ad spend, analyze which ad sets are performing best. Then, drop the losing ad sets and start to scale the winners.Now you are saving money and reducing your risk.Secondly,Use a call-to-action in your headline. One of the best ways to gain and hold your potential prospect's attention is to include a call-to-action in your headline.Most Facebook users who see your ad will decide if they are interested in your offer within the first 7 seconds of viewing it. That means you do not have a lot of time to get their attention. So instead of writing vague and boring headlines like,"We made an e-book. Check it out!"Write an exciting and detailed headline like,"Download now to learn how you can triple your Facebook ad results in 7 days, without spending twice the cash!". See the difference?Not only will your potential prospects be more interested in your offer, they will also know exactly what to do after reading your copy and viewing your image. And lastly,Drill down your targeting. If you are not targeting your potential customers correctly, there's no way you are going to achieve your sales goals. 99% percent of the time, businesses are not targeting correctly because they are not going deep enough.Let me explain:Your goal when running ads is to make sure the most passionate group of your target audience will see them. That way, you guarantee more sales. Let's say you sell running equipment. Instead of targeting people who list "Running" as an interest, target people who subscribe to popular running magazines, who follow influential figures in the running community, or who have bought running gear in the past.Now that's a passionate audience.All in all, if you use these three tips in your next Facebook ad, you are going to see amazing results in no time. So get out there and start advertising!If running and testing Facebook ads is not your strong suit, let's talk. We specialize in social media advertisements that guarantee powerful results. No more guessworkWhy did univision have an ad in english?You said you are bilingual. So are other people. Language is not regulated. In fact, I applaud them for doing it. Running an English Public Service blurb on a Spanish station was an excellent idea. It got your attention, did not it?Grub: adding Windows 10If you are booting in BIOS mode, there's not much you can do to make this work reliably (at least, last I knew there was not a reliable way without having separate hard drives for each install).If you are booting in UEFI mode though, it largely consists of creating a GRUB entry to chainload /EFI/Microsoft/Boot/bootmgfw.efi from your EFI system partition. You will also need to modify what Windows thinks the bootloader should be (or make your EFI variables read-only (only some firmwares let you do this)), otherwise Windows will update the EFI variables to point at it's own bootloader as the default every time you boot into Windows. I am not 100% certain about the exact command you need to pull this off (it's been too long since I had to set up my own system), except that it's done with bcdedit
Speed of Includegraphics Seemingly Dependent on How Many Packages Are Loaded!
This was quite a puzzle.This answer will be long, to match the long time it took me to get to the bottom of this, but the sections are titled and numbered so you can skip over the ones you don't care about. You can even skip to the one-sentence summary at the end. :-)This will describe how I arrived at the answer. If you don't care, and only want the answer, you can skip to the next section.I took the file at the top of the question, saved it into a file jfbu1.tex, also created foo.pdf by copying it as cp $(kpsewhich example-image-a.pdf) foo.pdf, then ran pdftex jfbu1.tex, and sure enough, saw output like:where the numbers are increasing.As what was being measured involved includegraphicsfoo.pdf, I tried to unpack the definition of includegraphics to see if it could be further simplified. (I also tried other things, like replacing D with 10000 occurrences of the expansion of A directly, but that didn't make a difference.) Well, showincludegraphics shows that its definition is leavevmode @ifstar Gin@cliptrue Gin@i Gin@clipfalse Gin@i , so let's replace includegraphics in our file with that, see if the phenomenon is still observed, and then try removing parts of it. (E.g. the first case of the @ifstar conditional is probably irrelevant, as we don't have a * in this example, so we won't take that path.)I did this a little, mostly relying on show, and cursing the complexity of LaTeX (just writing out the full definition of includegraphics in terms of TeX primitives would be immense). (Small tip: next time use the LaTeX source code rather than show; it's a bit easier to read.)Anyway, after a few steps of this (a few steps deep into the definition of includegraphics), I observed that we could replace the original file'swith (using just an early part of the definition of includegraphics):and the phenomenon of time increasing as we load more packages was still observed (though it ran faster). In fact, proceeding a bit, this was sufficient: apparently, simply testing whether a file exists takes longer as we load more packages!A few more steps, and we can get down to TeX primitives (no loading of graphicx necessary): which simply opens and closes the file (apparently this is part of how IfFileExists works internally).After making a few more changes  for example, we don't need the trick to convert pdfelapsedtime into seconds(?) as we care more about the fact that it's increasing than about its actual value, and the phenomenon is consistently observed even with much fewer repetitions instead of 10000 (say 81, replacing 10 with 3)  we arrive at the following slightly simpler file jfbu2.tex, where the phenomenon is still observed:and this still prints output like (not always the same numbers, but the pattern of increase is consistent):(About the useless thepdfelapsedtime before the D, which simply inserts "0" into the typeset output, I'll say more below.)And the mystery remains: the A above seems like it should just do a constant number of operations, why does it take longer as more packages are loaded?Now that we're down to TeX primitives, there's nothing further to unpack at the macro (the TeX programming) level, and we need to look into the TeX program itself.We can step through the TeX program with a debugger like gdb.To do this it would usually be easier to work with the LuaTeX source code, as that's (sort of) written directly in C, rather than the source code of TeX/pdfTeX/XeTeX, as they undergo several rounds of mangling from the .web source to the C code before being compiled. (So the C code that is finally compiled is more readable in the case of LuaTeX.) But it turns out (after appropriate definitions of pdfelapsedtime) that this phenomenon we're interested in does not happen in LuaTeX, so we're stuck with pdfTeX. (It does happen in TeX / XeTeX, where without the convenience of pdfelapsedtime we can just observe visually that it takes longer.)To use gdb, the program needs to be compiled with -g, and also binaries shouldn't be stripped. Fortunately I'd done this before: the trick is, when building from TeX Live sources (see here and here), instead ofto useand update $PATH to use the new binaries appropriately. (Or, if using make install strip, should replace with make install.)One can start gdb with a command like gdb pdftex (make sure PATH is right, or else specify the full path to our specially compiled pdftex binary). Then, one can set breakpoints, before running the program (as if we'd run pdftex jfbu2.tex on the commandline) with run jfbu2.tex.Which breakpoints to set? We'd like to stop when some particular function is called, which doesn't get called too often. My choice was the function called by pdfelapsedtime (though in hindsight I guess using the one for pdfresettimer would have been better) which with some looking at the source code and/or gdb, happens to be (or call) getmicrointerval. (This is the reason for the extra thepdfelapsedtime in the file above, because I want to break there.)So we can start gdb, set break getmicrointerval, and run the program, and it will stop after reaching the place where the function is called. Then we can type continue to continue until the next breakpoint (or end of program), or type next to invoke the next statement of the program (stepping over function calls, i.e. not descending into them) or step to do the same while stepping into function calls. As you keep hitting Enter, it will show you each function that's called, and each line of source that's executed.After doing this a little, it's clear that it will take a long time to do this manually.Long story short: put the following in /.gdbinit:This is like typing "step" and hitting Enter a few million times manually until the program finishes, and everything that gdb outputs will be written to file gdb.txt.With this, the whole thing ran for a few hours, and produced a gdb.txt that was over 700 MB in size, from over 20 million lines.The start of the file looks something like this:(The first Breakpoint 1 at 0x84bad: file pdftex0.c, line 3471 is printed when we set the breakpoint; we had continue after the first time gdb paused at the breakpoint so there's no output until the next.) The part shown in the output above is common to each time pdfelapsedtime is called (we haven't even got to the D part yet).Of course we can't process this 20-million several-hundred-megabyte file by reading through it manually. In fact, grep --line-number Breakpoint gdb.txt can be used to see the number of program steps executed between successive occurrences of pdfelapsedtime (calls to getmicrointerval):This shows thatwhere we can see the increase in the numbers in bold above. (Missed the first D because of the continue.)The main idea is that although the file is 20 million lines long, the set of different lines executed is much smaller, and what we want to compare is which lines were executed more frequently between each successive pairs of breakpoints.We can keep counters of which lines were executed how many times between successive occurrences of Breakpoint 1, getmicrointerval in the file. Used the following Python script:This is the first few lines of output for 2 (the second occurrence of D). The first column is the number of times executed, then what's printed by gdb (usually the line number and source line).Compare with that for 4 (the third occurrence of D, after tikz is loaded):and for 6 (the last one, after xlop is loaded):We can just do this visually, by say opening each in a separate tab and switching between them. For example, the (most frequent) while ( s > 255 ) loop or test is performed 2502900 times after tikz.tex is loaded, compared to 975726 times before. Everything after (less frequent than) zsearchstring is run the same number of times (among statements executed at least 500 times say), and everything above that is from inside the zsearchstring function, or from the zstreqstr function just above (called from zsearchstring). So the culprit is entirely this zsearchstring function in pdftex0.c.If we understand what this zsearchstring is and why it's called, it concludes the debugging process.If you skipped the previous section: so far we've found that all the additional work between different calls of D happens in the function zsearchstring in pdftex0.c, which seems to be invoked more times (and executes a lot more operations) as more packages are loaded. Why?We can see the entire definition of zsearchstring in pdftex0.c or for that matter in tex0.c (which are both inside Build/source/Work/texk/web2c/ in the texlive directory):But at first glance it does not appear to be used anywhere else in the file. That's because in pdftexcoerce.h (or texcoerce.h) you'll find a declaration and a macro defined as it:and you can indeed find searchstring used a few times in pdftex0.c or tex0.c.This C code is somewhat harder to read than necessary though. In fact, the list of files where searchstring is found includes tex.p, which is presumably the result of tangling tex.web. Yet if you look in the TeX source code (with texdoc tex say), you will not find this function, as it's not part of the code that Knuth wrote. It's instead part of the system-dependent changes  changes made in web2c to produce a working TeX program. Instead you need to look at the complete (pdf)TeX source, with the change files too. Something like the following (assuming that texlive is the texlive directory):to produce a pdftex.tex file, followed by pdftex pdftex.tex (after optionally changing the input webmac to input pdfwebmac). (One could also look in the .ch file directly, but WEB code is ugly and is best not looked at directly.)Now we can look in the resulting PDF for search_string.Here's the definition of search_string; compare with our earlier zsearchstring C code above (generated from this):This finally explains what search_string is and why it exists. (We'll say more below.) Looking at places where it's used makes things even more clear. It's used in three procedures: end_name, start_input, and slow_make_string. Let's look at the first two:Compare with the corresponding sections in the TeX program: 517 and 537, which don't use search_string after calling make_name_string. It's worth looking at the definition (at least the documentation / context) of that too:We saw above that these functions are called when scanning a filename in an input, openin or openout operation. This of course includes the includegraphicsfoo.pdf example in the question, and the openin in the reduced example.Note that sometimes scanning does not require creating a string: we can see this by changing the test case to:where the phenomenon is not observed. (Well I haven't run it through gdb, but the numbers do not increase.)Also see why working with filenames required system-dependent changes in the first place  at the time TeX was developed, file names were very inconsistent across operating systems; in fact in the place where TeX was developed (SAIL), file names consisted of a base, extension and an area that included the user's initials and project (or something like that).Some background, for understanding the context of the code we saw above. At the time Knuth was originally (re)writing TeX (19801982), the programming language Pascal (at least the version available to him and at many places where TeX was going to be used) did not have good support for strings. So TeX basically takes care of allocating all strings manually: there's a giant array of characters called str_pool, initialized at the start of the program, and whenever TeX needs to store a new string, it stores the characters of the new string (as it's being built up, e.g. scanned from the input file) at successive indices into this array. For example, the kth string starts at str_poolstr_startk and goes up to str_poolstr_startk1-1. Or you can read this in the program:Note that the string pool is just an array, and is not optimized for finding strings in it: the TeX program as originally written saves references to whatever strings are needed (e.g. it will save k, and thereby know where to find the kth string). It never needs to look through all strings in the array for a particular string, any more than it's reasonable to search through all bytes of a computer's memory looking for a particular value.But when the system-dependent changes for web2c were made (a long time ago), a function slow_make_string was introduced which before saving a string, searches the entire string pool(!) to see whether it's already present under some other name (number). If so, the same string (number) is reused. This explains the very frequent (executed millions of times) loop ofthat we saw in gdb: it's searching through all string numbers s, starting at the largest (most recent) value.It appears that this may have made sense when memory constraints were tighter than time constraints (you can always wait longer), especially as it would also mean the string pool was small so there was a smaller limit on how much time would be spent searching through the entirety of it. At current memory sizes (and memory access times, which have over the last many decades consistently become more expensive relative to (arithmetic) CPU instructions) it may be worth reconsidering...(TeX as originally written does not do this. From some of the documentation it's worded as though TeX simply creates this new string, stores no reference to it, and moves ahead, which sounds like a typical memory leak bug  possibly worthy of one of those reward cheques from DEK? :P  but from looking at some of the code it seems rather that TeX unconditionally flushes the string, so it's rather the case that the changed (web2c) TeX wants to preserve a reference for some reason, so it needs this workaround... it's not clear to me which is the case.)Apart from TeX Live, I took a look at MiKTeX, and it has nearly identical code for these sections. (Just renamed from 54/web2c-string to 54/MiKTeX-string.) I have not been able to look at other less common (not based on web2c) TeX distributions, like KerTeX or TeX-gpc, nor of course of closed-source (commercial) distributions like BaKoMa TeX or Texpad.At the end of a TeX run, if tracingstats1, the program prints statistics to the log file (Here is how much of TeX's memory you used). These are the results by moving the bye to different places in the above file (after adding tracingstats1):At the top of the file (just after tracingstats1):After A, B, C, D have been first defined:(Doesn't change because single-letter names are not stored separately.)After those and also filename has been defined:(Makes sense: filename is one string, and 8 characters long.)Just before the first D:(The two strings of 19 bytes total are not the primitives pdfresettimer and pdfelapsedtime (those would be already stored), but rather something created by thepdfelapsedtime. Not sure of the details.)Just after the first D, or just after the first message:After input xintexpr is loaded (and any place before input tikz):After input tikz:(Note the large increase compared to earlier.)After input xlop (or end of file):These relative increases in the size of the string pool roughly match the relative increases in the time for executing D.In the common implementations of TeX, commands in which TeX scans for a file name (as in the case of includegraphics) involve searching through the entire string pool, and this gets slower as more packages are loaded because the packages define control sequences (macros) whose names are stored in the string poolHere is test file for (Plain) pdftex. To test it, you need some graphics file foo.pdf in working repertory. Mine is a copy of the file found via kpsewhich example-image-a.pdf. Call the following testspeedgraphics.tex and execute pdftex testspeedgraphics on command line.input graphicx.texdefBnoexpandAnoexpandAnoexpandAnoexpandAnoexpandA% noexpandAnoexpandAnoexpandAnoexpandAnoexpandA%edefCBBBBBBBBBB% 100 AdefAnoexpandC%edefDC% 100 C, each one expanding to 100 AdefAsetbox0hboxfoodeffooincludegraphicsfoo.pdfpdfresettimerD % 10000 usage of includegraphicsedefzzzthedimexprpdfelapsedtime spmessage^^J^^J**** zzz ****^^J^^Jinput xintexpr.stypdfresettimerD % 10000 usage of includegraphicsedefzzzthedimexprpdfelapsedtime spmessage^^J^^J**** zzz ****^^J^^Jinput tikz.texpdfresettimerD % 10000 usage of includegraphicsedefzzzthedimexprpdfelapsedtime spmessage^^J^^J**** zzz ****^^J^^Jinput xlop.texpdfresettimerD % 10000 usage of includegraphicsedefzzzthedimexprpdfelapsedtime spmessage^^J^^J**** zzz ****^^J^^JbyeThis file will do 4 times 10000 includegraphicsfoo.pdf in box0. We load more and more packages. On a 2.8GHz computer I get this typically in the console output:**** 1.12306pt****(loading of xintexpr)**** 1.19366pt****(loading of tikz)**** 1.36714pt****(loading of xlop)**** 1.40392pt****Hence there is increase of timings, and one feels the bigger the package the more the impact.Now comment out all loading of extra packages in test file above and repeat experiment. I get typically**** 1.13177pt******** 1.12141pt******** 1.14122pt******** 1.12416pt****i.e. there no timings drift...Now another test file, where we still include graphicx.tex but do no usage of includegraphics, rather we expand a dummy macro foo. This being much faster we do 1000000 repetitions.input graphicx.texdefBnoexpandAnoexpandAnoexpandAnoexpandAnoexpandA% noexpandAnoexpandAnoexpandAnoexpandAnoexpandA%edefCBBBBBBBBBB% 100 AdefAnoexpandC%edefDC% 100 C, each one expanding to 100 AdefAnoexpandD%edefEC% 100 D, each one expanding to 100 CdefAsetbox0hboxfoodeffoofoopdfresettimerE % 1000000 "foo"edefzzzthedimexprpdfelapsedtime spmessage^^J^^J**** zzz ****^^J^^Jinput xintexpr.stypdfresettimerE % 1000000 "foo"edefzzzthedimexprpdfelapsedtime spmessage^^J^^J**** zzz ****^^J^^Jinput tikz.texpdfresettimerE % 1000000 "foo"edefzzzthedimexprpdfelapsedtime spmessage^^J^^J**** zzz ****^^J^^Jinput xlop.texpdfresettimerE % 1000000 "foo"edefzzzthedimexprpdfelapsedtime spmessage^^J^^J**** zzz ****^^J^^JbyeThis test file does all the input's of extra packages. Typically I get from pdftex testspeedfoo.tex:**** 0.48016pt****(xintexpr)**** 0.49115pt****(tikz)**** 0.48283pt****(xlop)**** 0.47798pt****i.e. no impact at all.Now, why is there impact with includegraphics. Is it simply because its expansion is much more complex, and if yes what is explanation? or is it something specific related to includegraphics dealings and then again what is explanation?Perhaps something having to do with hash-table? the more macros are defined the less efficient TeX is in expanding macros? (then the thing would be not includegraphics specific, I stopped my testing there, leaving the experts to express their intuitions first).Originally, this question arose in the context of a Joseph answer using xfp and includegraphics. I wanted to test if using draft option of includegraphics had an impact and then realized that loading or not xfp changed the timings. Then I realized it had nothing xfp specific, but any big package would do.I also tested with this variant of foo:defAsetbox0hboxfoodeffoofooadeffooafoobdeffoobfoocdeffoocfooddeffoodfooedeffooefoofdeffooffoogdeffoogfoohdeffoohfooideffooifoojdeffoojfookdeffookfooldeffoolfoomdeffoomfoondeffoonfooodeffooofoopdeffoopfooqdeffooqfoordeffoorfoosdeffoosfootdeffootfooudeffooufoovdeffoovfoowdeffoowfooxdeffooxfooydeffooyfoozdeffoozfooAdeffooAfooBdeffooBfooCdeffooCfooDdeffooDfooEdeffooEfooFdeffooFfooGdeffooGfooHdeffooHfooIdeffooIfooJdeffooJfooKdeffooKfooLdeffooLfooMdeffooMfooNdeffooNfooOdeffooOfooPdeffooPfooQdeffooQfooRdeffooRfooSdeffooSfooTdeffooTfooUdeffooUfooVdeffooVfooWdeffooWfooXdeffooXfooYdeffooYfooZdeffooZfooaadeffooaafoobbdeffoobbfooccdeffooccfoodddeffooddfooeedeffooeefooffdeffoofffooggdeffooggfoohhdeffoohhfooiideffooiifoojjdeffoojjfookkdeffookkfoolldeffoollfoommdeffoommfoonndeffoonnfoooodeffoooofooppdeffooppfooqqdeffooqqfoorrdeffoorrfoossdeffoossfoottdeffoottfoouudeffoouufoovvdeffoovvfoowwdeffoowwfooxxdeffooxxfooyydeffooyyfoozzdeffoozzfooAAdeffooAAfooBBdeffooBBfooCCdeffooCCfooDDdeffooDDfooEEdeffooEEfooFFdeffooFFfooGGdeffooGGfooHHdeffooHHfooIIdeffooIIfooJJdeffooJJfooKKdeffooKKfooLLdeffooLLfooMMdeffooMMfooNNdeffooNNfooOOdeffooOOfooPPdeffooPPfooQQdeffooQQfooRRdeffooRRfooSSdeffooSSfooTTdeffooTTfooUUdeffooUUfooVVdeffooVVfooWWdeffooWWfooXXdeffooXXfooYYdeffooYYfooZZdeffooZZfooto try to emulate the case with expansions of many distinct macros. But this does not show any drifting when loading packages, i.e. I don't reproduce with that the includegraphics situation: all four executions of 1000000's A take each about 2.9s--3s on my 2.8GHz computer.
How Much Does a Hamster Cage Cost?
Getting hamster for your child involves finding the right hamster cage and the feeding and bedding accessories that go with it. Before you bring the hamster, check out the costs of ownership.Hamster  CageThe most important thing that you will need is the hamster cage. This will be where your hamster will live. There are lots of different types of cages. These can be purchased for anywhere between $10 for a small plastic cage up to $100 for a larger cage made of metal or wood.BeddingBedding material is important as it will make your hamster cage comfortable for the hamster. This will cost between $2 and $10 depending on whether you choose basic bedding, or whether you prefer the scented varieties. Prepare to replace bedding weekly as part of your cleaning regimen.Dish and FoodA dish to put food in is a very good idea, it's best to buy a ceramic bowl so that hamsters can not chew and eat it. This should only cost up to a maximum of $10.Food is also necessary and you can buy lots of different mixes of hamster food at your local pet shop. These should not cost any more than a few dollars for a small bag to try out.BottleAll animals need to drink and hamsters are no exception. Expect to pay up to $5 for a water bottle. A bowl of water could be used instead however bottles are much cleaner and less likely to make a mess.Can guinea pigs eat hamster food?Ignore that person above! I feed my guinea pigs hamster food because I have like 7 hamster lol :) they are perfectly fine and I've won loads of pet shows XD they've been alive for years too :PI lost the tablespoon i use to measure my hamster food?Hi Yes, that's ok. It would be just like you hamster chewing his/her cage or plastic igloo, or any other toy or item that's plastic. It is 100% safe if your hamster has chewed the measuring tablespoon. If I were you I would clean the cage to find it. If it's not in the cage do not worry, just look around the cage, in the floor, under the bed, just any place like that. I would also ask your mom where she put it because it might not be in the cage at all. Hope I have helped you!Is it possible to make homemade hamster food? If so do you have any recipes?I have one! Ingredients: Diffrent types of seeds(unsalted) honey put some of the seeds in a bowl. put honey and form balls. let the honey dry for it hardens. put one ball at a time in!is it okay to feed pet mice hamster food?Hamster food is different. Maybe post on craigslist if someone is willing to tradeWhat foods (other than hamster food) can i give to my hamsters?A hamsters diet mainly consists of a dried mix that can be bought in pet stores. This will contain all the vitamins and minerals a hamster needs. Make sure the mix you buy does not contain too many seeds or nuts because too many of these can make your hamster fat. One thing to note when feeding dwarf hamsters is not to feed too many sugary foods as this could lead to diabetes. You should provide two teaspoons of the dry mix each day. Any food that your hamster does not eat should be thrown away. Along with the normal hamster mix you can also feed your hamster fresh fruit and vegetables once or twice a week. Be careful you do not feed too many of these as it may cause the hamster to get diarrhoea. The following is a list of some foods you can feed your hamster: Banana Sweetcorn Cucumber Apple Cheese Turnip Raisins Peas Carrot Celery Bread Grapes Melon Chicken Never feed your hamster these foods: Chocolate Raw Kidney Beans Garlic Onions Raw Potato Sweets Hope this helps.Hamster Food, Treats & Diet: What Types, How Much & OftenFeeding your hamster is going to be relatively easy considering all the food options that are available to you. With that said though, not every type of hamster food is good for them. Some of your options include carefully formulated ingredients that will provide your hamster a well-balanced diet while others do not provide any nutritional value and are loaded with nothing but sugars or fats. The hamster food you should look for includes 12-24% protein and 3-6% fat. For Pregnant or baby hamsters, you should get hamster food that contains 18-40% protein and 7-9% fat. The reason pregnant mothers and babies need more protein is that they need all the protein to grow. It's during the first month of a baby hamster's life that does most of it's growing; additional protein will help. In addition to the protein and fats, they need a diet high in carbohydrates. Since they burn so much energy when they are active, hamster food with some needed carbs will give them the energy to do their nightly exercise on the hamster wheel or through their tubes and tunnels. Round out the diet with greens in the forms of lettuces, grasses, fruits, and vegetables. What is in Hamster Food With all the options available and all the guidelines you need to follow, you are probably wondering what exact type of hamster food to get. The problem is, there is no one right answer. We can give you a recommendation on what we think makes a well-balanced hamster diet but by no means is this always going to be right for your situation. In addition to pregnant and baby hamsters, you might need to alter your diet formula for any obese, old, or diabetic hamsters. Obese hamsters should be limited in their fat intake, old hamsters can be fed what the babies eat and diabetic hamsters should have low sugar diets. In regards to prepackaged hamster chow, these should make up more than 50% of the overall diet. There are two main types to choose from; seed mixes and lab blocks of pellets. Variety is the spice of life so it's okay to use both in your hamster's diet. A bag of mixed seeds is a great choice if you want a large variety of options for your hamster to eat. Depending on the brand, theses mixes include not only seeds but also and other types of grasses/grains (oats, wheat) dried fruits and vegetables. If your hamsters ate a bit of all these ingredients, it would probably have a relatively balanced diet. However, just as you see in humans, hamsters will pick and choose what they want to eat. Often they will go for the more fatty foods like sunflower seeds or pumpkin seeds while not eating the other parts of the mix. Thus, they do not get a well-balanced diet. You can pick out the fatty seeds like sunflower and pumpkin seeds and only give them out every so often. You might consider removing some of the corn or alfalfa since some hamster owners say they can cause cancer or liver damage but there is little research to back this up from what we can find. Additionally, dehydrated fruits can get stuck in their mouths or cause a cheek impaction. Finally, avoid mixes that have a lot of molasses in them since they are full of sugar. Lab blocks were originally created as feed in laboratories for research animals. You can now buy these at pet stores but the best ones still come from manufactures that still sell to laboratories. A lab block usually contains a mixture of seed and grains and vitamins and minerals. These are a preferred type of hamster food if you want to make sure your little guys or girls are getting all the vitamins and minerals they need to stay healthy. If you could only get one type of dry food, these would be them. You might think they would taste bad but your hamsters will most likely love them, especially the Syrian breeds. In addition to getting a well-balanced diet, these pellets and blocks will help wear down your hamster's teeth and keep them from becoming overgrown. Lastly, Block and pellets are easier to save while cleaning your hamster cage then the smaller seed mixes. Hamsters in nature rarely drink water but instead get their water from the things they eat (This does NOT mean you do not need a water bottle though). Fresh greens, fruits, and vegetables not only provide your hamsters with the water they need, but they also provide extra vitamins and minerals they need. With that said, you need to be careful how much greens you add into the hamster food; too many greens and they can get a case of diarrhea. A rough guide calls for only feeding it about one square inch (2.54cm) of greens per day. There are greens, fruits, and vegetables that are great for hamsters and there are also ones that should be avoided. The following are some of the greens that are acceptable and some of the greens to avoid (If you collect these from outdoors, make sure there are no pesticides or toxic chemicals that could be on them. Always thoroughly wash them before placing them in your hamster's cage.) • Corn (may or may not cause cancer) • Alfalfa (may or may not cause cancer) In their natural habitat hamsters are mainly herbivores but on occasion, if the opportunity arises, they will snatch up small insects or grubs. This means you will need to provide your pet with some food that contains protein. Many of the prepackaged mixes will have some protein so you wo not have to provide that much more. All you need is a small fingers worth every so often. Try to keep its protein intake down around 12-15% unless otherwise for reasons stated in this article (pregnant and baby hamsters). The following is a list of acceptable forms of protein that can be fed to them (It's best to get any of the live insects/bugs on this list from the pet store so no diseases get spread). Hamsters need access to a fresh source of water 24/7. The best way to do this is by providing them with a water bottle or two throughout their habitat. You need more than one if you have several hamsters or an expansive cage system. In the wild you could observe a hamster licking different rocks or minerals that contain salt. They need salt to help retain water and stay healthy. You can provide your hamster with a salt lick or a mineral salts. These come in various forms and are sometimes added to their accessories as a form of play. If you provide your little guy with a well-balanced diet you probably wo not need to get supplements to add extra vitamins and minerals into their food or water. However, if you want to play it safe and make sure they are getting all the nutrition they need, you can get vitamin and mineral supplements; it more than likely wo not do them any harm as long as you follow the directions. Occasionally a pet owner wants to spoil their hamsters by giving them some treats. For the most part, if you feed it a well-balanced diet it wo not need to be fed any treats. However, every so often it's okay to give your hamster something that is not the best for it in terms of nutritional value. If anything, if it does not provide any nutritional value, a tasty treat might improve their happiness which is a roundabout way can improve the little guy or girl's well being. There are a lot of options on the market these days and some are less unhealthy than others. Most of them come in flashy packaging and contain a lot of sugar. Here is a list of some of the treats that are available: Avoid any treat that contains a high amount of sugar. This means no cakes, cookies, or chocolates. If you only spoil your hamster every so often and do not fall for their tricks that they just have to have a treat, then you are being a good pet hamster owner and providing them with the proper care they need.
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