Business Law exam 2 Essay Example | Topics and Well Written Essays - 750 words

Business Law exam 2 - Essay Example This indicates that the female employee was not being pressurized through organizational apparatus to socialize with the male employee. There is some indication to the creation of a hostile environment by the female employee herself by socializing with a male employee in this fashion. The female employee’s adverse reaction to the male employee’s advances changed the situation altogether. She was denied fair compensation and pay raise for her work. There is little explanation for the sudden fall in her quality of work from the company’s end making coercion through official apparatus a strong possibility. The lack of response from the human resources department especially its lack of providing a sexual harassment mechanism to deal with the situation is also clear. This also serves to indicate that employer and his other agents were fully aware and complacent over the situation. The female employee had to seek psychiatric assistance in order to resolve her issues, w hich in turn indicate grievous damage to herself. Such conduct had both a â€Å"deleterious† as well as â€Å"severe and pervasive† effect on the female employee without doubt. Furthermore, the harassment occurred during employment which makes the employer vicariously liable. The move by the male employee to settle down the situation by offering greater rewards also casts doubt on the male employee’s motives. Given the circumstances of the case, it is clear that sexual harassment laws apply to the case. The employer’s attitude of ignoring complaints made by the female employee means that the tort of Constructive Damage has been set in motion. On another note, it is clear that although sexual undertones and overtones may have existed in the organization but these were latent only. In this fashion, such sexual tones cannot be considered as hostile environment. Furthermore, the female employee’s outstanding performance in the first six

Why does it matter what shape a molecule has Essay

Why does it matter what shape a molecule has - Essay Example These are the contexts in which the manner in which materials behave are described, whether they are simple gases, or complex biological structures. The bonds between atoms have distinct lengths, energy and direction which distinguish the atomic structure of materials. The shape of a molecule is formed by the spatial relationships of chemically bonded atoms, and this feature contributes significantly to understanding how molecules react with each other. Ionic bonds are formed by the electrostatic attraction between a cation and an anion. The electric field of an ion has spherical symmetry, hence ionic bonds have no directional character. Contrastingly, covalent bonds are formed by the overlap of atomic orbitals. Since the overlap is such that the atomic orbitals can attain maximum overlap, a covalent bond has a directional character. Therefore, â€Å"the shape of a molecule is determined by the angle between two bonds, which in turn is determined by the atomic orbitals that form the bond† (Iwanami 2006, p.1). Thesis Statement: The purpose of this paper is to investigate why the shape of a molecule is significant in the study of chemistry. ... The attraction between two adjacent non-polar molecules increases in proportion to the area of contact. Generally, the closeness of the tie between the two increases with greater area of van der Waal’s contact attraction and also with the degree of hydrogen bonding. The higher the level of molecular fit, the stronger is the affinity between a molecule and the biomolecular target in therapeutic agents. A therapeutic agent or medicine in aqueous solution is stablized by hydrogen bonding to water and dipolar solvation. It is evident that in medicines, there is a trade-off; they must be sufficiently well solvated to be soluble in water, â€Å"but not so strongly solvated that they cannot be pulled from solution by the target biomolecule† (Corey et al 2012, p.55). Noncyclic organic molecules are usually flexible because the barrier to rotation about single bonds having low energy. Therefore, most medicines’ structures have cyclic subunits with a few preferred conforma tions, sometimes just one. Fig.1a. and 1b. show the conformation of prednisone, a significant anti-inflammatory and immunosuppressive drug, along with the preferred conformation of glucose. Fig.1a. Chemical Structure of Glucose Molecule (Corey et al 2012, p.56) Fig.1b. Prednisone Chemical Structure (Corey et al 2012, p.56) While the molecular formula for glucose is C5H12O6, the formula for prednisone is C21H26O5. â€Å"The polycyclic framework of prednisone is quite rigid and gives the molecule a characteristic shape† (Corey et al 2012, p.56). Concurrently, several polar functional groups are situated at specific sites in space, facilitating their optimal binding to the target molecule. The Different Shapes of Molecules Based on Structure There are compounds with a divalent central

Personal ethics development Essay Example | Topics and Well Written Essays - 750 words

Personal ethics development - Essay Example The process of testing rules comprises of its universality i.e. can the rules be universally applied to everyone or it treats people as ends but not the means. Every individual has some of the sources where he or she draws some of the basic principles in life that forms the basis of what is wrong or right behavior. In several instances, the following are some of the major sources of ethics. Childhood upbringing- every person learns ethics from his or her parents through either words or most importantly through their actions. I learned some of the ethics by observing and listening and observing what my parents as I grew up. Life experience- at a later stage in life, some of the events directly and consciously shapes the ethics of an individual. For instance, an individual who was treated unfairly during a road accident may most likely have negative attitude in life towards people who treated him or her unfairly. Religious beliefs- nearly most of the religions in the world teach similar code of ethics that emphasizes on respect for other people’s rights, honest and selflessness. Therefore, whether in business or in business situations, religious people act in a manner that is seen as being ethical A person’s ethics can be displayed in the place of work since an individual and the organization can both affect each other’s actions and behavior. Team leaders have a great impact on their team’s behavior and ethics. A place of work is a good place to learn ethics since employees affect each other’s psychology and moral behavior. Therefore employees act as each other’s source of inspiration Good ethics assist an individual in understanding his or her working environment. It also assists an individual to wheedle with team members both in junior and senior positions in a friendly way. This assists in creating conducive working environment thus increasing the performance level. A

Why does it matter what shape a molecule has Essay

Why does it matter what shape a molecule has - Essay Example These are the contexts in which the manner in which materials behave are described, whether they are simple gases, or complex biological structures. The bonds between atoms have distinct lengths, energy and direction which distinguish the atomic structure of materials. The shape of a molecule is formed by the spatial relationships of chemically bonded atoms, and this feature contributes significantly to understanding how molecules react with each other. Ionic bonds are formed by the electrostatic attraction between a cation and an anion. The electric field of an ion has spherical symmetry, hence ionic bonds have no directional character. Contrastingly, covalent bonds are formed by the overlap of atomic orbitals. Since the overlap is such that the atomic orbitals can attain maximum overlap, a covalent bond has a directional character. Therefore, â€Å"the shape of a molecule is determined by the angle between two bonds, which in turn is determined by the atomic orbitals that form the bond† (Iwanami 2006, p.1). Thesis Statement: The purpose of this paper is to investigate why the shape of a molecule is significant in the study of chemistry. ... The attraction between two adjacent non-polar molecules increases in proportion to the area of contact. Generally, the closeness of the tie between the two increases with greater area of van der Waal’s contact attraction and also with the degree of hydrogen bonding. The higher the level of molecular fit, the stronger is the affinity between a molecule and the biomolecular target in therapeutic agents. A therapeutic agent or medicine in aqueous solution is stablized by hydrogen bonding to water and dipolar solvation. It is evident that in medicines, there is a trade-off; they must be sufficiently well solvated to be soluble in water, â€Å"but not so strongly solvated that they cannot be pulled from solution by the target biomolecule† (Corey et al 2012, p.55). Noncyclic organic molecules are usually flexible because the barrier to rotation about single bonds having low energy. Therefore, most medicines’ structures have cyclic subunits with a few preferred conforma tions, sometimes just one. Fig.1a. and 1b. show the conformation of prednisone, a significant anti-inflammatory and immunosuppressive drug, along with the preferred conformation of glucose. Fig.1a. Chemical Structure of Glucose Molecule (Corey et al 2012, p.56) Fig.1b. Prednisone Chemical Structure (Corey et al 2012, p.56) While the molecular formula for glucose is C5H12O6, the formula for prednisone is C21H26O5. â€Å"The polycyclic framework of prednisone is quite rigid and gives the molecule a characteristic shape† (Corey et al 2012, p.56). Concurrently, several polar functional groups are situated at specific sites in space, facilitating their optimal binding to the target molecule. The Different Shapes of Molecules Based on Structure There are compounds with a divalent central

The Sin Tax bill Reaction Essay Example for Free

The Sin Tax bill Reaction Essay The Sin Tax bill (House Bill 5727 and Senate Bill 3249) is a bill which aims to restructure the existing taxes imposed on alcohol and tobacco goods. On December 20, 2012, President Benigno Aquino III signed the Republic Act 10351 or the sin tax reform 2012. The Sin Tax Bill is a sensationalized issue in the Philippines and it gets several mixed reactions from different stakeholders in the country or Filipinos at large. Filipinos are expected to reduce their vices like alcoholism and smoking as a target result of this Bill. Aquino said the new law aims to favor both the government and the Filipino people since revenues to be generated from the measure will be used to fund health insurance programs for the poor, and build and renovate hospitals in the country. Most families of Filipinos especially those who are not residing in urban areas are farmers. The source of their livelihood is farming tobacco products and harvesting fermented liquors, in our dialect â€Å"tuba†. They are now the immediate concern that the government should consider upon the approval of this Bill. Higher taxes on tobacco products mean lesser income for these farmers. Especially, that they are not the owner of the lands they’re farming, they also pay lease for the lands. Unemployment is one of the possible outcomes of the Sin Tax Bill, especially on our farmers. If they become jobless, they likely can resort to different illegal activities just to provide for their family. The aim of the Sin tax Bill is to discourage smokers and alcoholics. But the problem here is that, especially on Filipinos who claim that these vices are addiction to them, they would still continue smoking and drinking alcoholic beverages, to the point that they would sacrifice some of the immediate needs of their families just to sustain their wants. Filipinos are very steadfast on every endeavor they undertake. But they have this mindset that the Programs of the Government are not reaching the true and deserving beneficiaries, like farmers. They may not benefit from these health programs because in the first place they are not living in the cities where standard and quality health responses are located. Maybe these projects may be beneficial to the Filipinos but what of the immediate impact on these increases of taxes? Different Tobacco and Alcoholic Beverages companies might also decrease the salaries of their workers or lay-off employees because its production will become more expensive. It will really affect factory workers and even small-scale business owners. On the other hand, I think this Sin Tax Bill has its positive goals especially to the youth of the nations. Most consumers of these â€Å"sin goods† are youth. With the presence of this bill, there will be higher prices on different cigarettes and alcoholic drinks and since they cannot afford it, they will be discouraged to smoke and drink alcohols. Let’s just cross our fingers that the youth will not resort to illegal means just to continue their vices, especially the out-of-school-children-and-youths. Since they do not have a proper education, we should take it into account that OSCYs are more vulnerable to these vices and if they are not guided properly, this Sin Tax Bill will make sins bigger.

A Hydraulic Accumulator Energy Engineering Essay

A Hydraulic Accumulator Energy Engineering Essay A hydraulic accumulator is a device in which potential energy is stored in the form of a compressed gas or spring, or by a raised weight to be used to exert a force against a relatively incompressible fluid. They are used in fluid power systems to accumulate energy and to smooth out pulsations. Accumulators store energy when hydraulic system pressure is greater than the accumulator pressure and provide hydraulic energy when the accumulator pressure is greater than the system pressure. By storing and providing hydraulic energy, accumulators can be used as a primary power source. Accumulators are inherently dynamic devices, they function when configuration changes (actuators moving, valves opening, etc.) are occurring within a hydraulic system. Accumulators respond very fast to configuration changes, nearly instantaneously for gas accumulators. They are usually used in conjunction with a pump/motor in a hydraulic circuit. A hydraulic system utilizing an accumulator can use a smaller fl uid pump since the accumulator stores energy from the pump during low demand periods. The pump doesnt need to be so large to cope with extremes of demand, so that the supply circuit can respond more quickly to any temporary demand and to smooth pulsations. The capability and affect of the accumulator is determined by the overall volume of the accumulator and preload/pre-charge of the spring/gas. There are 4 types of accumulators: bladder, diaphragm bladder, piston (either spring or gas controlled) and metal bellows. The choice of accumulator to use in a given application depends on required speed of accumulator response, weight, reliability and cost. Pressurized gas accumulators will have the faster dynamic response and are reliable. Metal bellows accumulators are very reliable, but will not respond as fast as a pressurized gas accumulator. Accumulators with seals generally have the lowest reliability. Accumulators are either spherical or cylindrical in design. Bag, piston and metal bellows accumulators are cylindrical. Diaphragm accumulators may be spherical or cylindrical. Accumulators are usually manufactured into 2 halves which are either welded or threaded together. A fill port is installed at one end of a gas accumulator and the hydraulic connection fitting (with poppet valve, if required) is installed at the opposite end. For a spring accumulator, the non pressure sid e usually has a fitting that connects to the hydraulic reservoir (for seal leakage and to alleviate back pressure on a piston). Materials are usually steel, but accumulators may also be made from aluminium or a composite (filament wound) material. Compressed gas accumulators are by far the most common type; these gas accumulators take advantage of the fact that the gas is compressible. A gas accumulator has a gas pre-charge that is less than the nominal hydraulic system pressure. As hydraulic fluid enters the accumulator the gas is compressed to the nominal system pressure, which is an equilibrium position and represents the maximum amount of energy stored by the accumulator. As system hydraulic pressure drops, the gas will expand pushing hydraulic fluid back into the system. The gas pre-charge level is an important parameter for gas accumulators since the pre-charge and overall accumulator volume; determine the maximum amount of hydraulic energy that will be available to the system. The pre-charge is the pressure of the gas in the accumulator without hydraulic fluid in the fluid side. A gas accumulator is pre-charged with nitrogen gas when there is no hydraulic fluid in the accumulator to the desired pressure. The gas accumulator pre-charge is a very important variable for ensuring optimal accumulator performance and maintaining long life of the accumulator. Too high of a pre-charge pressure and the fluid volume capacity is reduced. Furthermore, if a bag accumulator charge is too high than the bag may hit the poppet valve which could damage the bag through repeated hits in service, or cause a fatigue failure in the poppet valve assembly. For a piston accumulator, the piston may be driven into the stops repeatedly affecting seals or cause a fatigue failure in the piston stop. Too low of a pre-charge pressure and the accumulator may not maintain desired minimum hydraulic system pressure. Also a low pre-charge pressure will allow a piston accumulator to repeatedly hit the up stops leading to premature failure of the accumulator. For a bag accumulator, the bag may be forced into an unnatural shape (e.g.,with folds) leading to bag damage and premature bag failure. When sizing an accumulator the pre-charge pressure is an input to the sizing process. However, once the accumulator is sized the minimum and maximum gas volumes should be computed (under worst case conditions) and analyzed to ensure piston stops are not hit or that a bag cannot fully collapse or expand completely in the accumulator. Bladder Accumulator A bladder accumulator consists of pressure vessel with an internal elastomeric bladder with pressurized nitrogen on one side and hydraulic fluid on the other side (system side). Figure 1 shows a bladder accumulator. It has 3 stages of operation: The accumulator is charged with nitrogen through a valve installed in the top. The accumulator will be pre-charged to nominal pressure when the pumps are not operating. Secondly when nominal hydraulic system pressure is applied the bag will be compressed to its fully compressed state. When the bag is fully compressed, the nitrogen pressure and the hydraulic pressure are equal. Finally as system pressure drops the bag expands, forcing fluid from the accumulator into the system. As the bag expands pressure in the bag decreases. The bag will continue to expand until the bag pressure equals the hydraulic pressure (which will be lower than nominal system pressure) or the bag fills the entire accumulator volume which is an undesirable situation. A poppet valve keeps the bag in accumulator from being pulled into the downstream tubing should the bag over-expand. If the bag was pulled into the downstream tubing, the accumulator would never recharge and normal flow from the pump would be constricted. The maximum flow rate of the accumulator is controlled by the opening area (orifice) and the pressure difference across the opening. Figure http://www.globalspec.com/NpaPics/18/146314_030520074661_ExhibitPic.JPGAccumulator, Bladder Typehttp://www.globalspec.com/NpaPics/18/146314_030520074661_ExhibitPic.JPG The main advantages of a bladder accumulator are fast acting, no hysteresis, not susceptible to contamination and consistent behaviour under similar conditions. Accumulators are easy to charge with the right equipment. Because there is no piston mass, the speed of the bladder accumulator is governed by the gas, which reacts very fast to changes in hydraulic system pressure. Hence bladder accumulators are the best choice for pressure pulsation damping. Also, the bladder attachment internal to the accumulator has proven to be very reliable in service. Of course there is always the potential for bladder failure, which is a failure that would not usually be detectable in service. Also, temperature differences on the gas will have some affect on performance. The main limitation of bladder accumulators is the compression ratio (maximum system pressure to pre-charge pressure) which is limited to approximately 4 to 1. Hence gas accumulators will be larger than other accumulators for the same flow requirements. The pre-charge pressure is typically set to approximately 80% of the minimum desired hydraulic system pressure. Diaphragm Accumulator A diaphragm accumulator is similar to bag accumulator except an elastomeric diaphragm is used in lieu of a bag. This would typically reduce the usable volume of the accumulator so the diaphragm accumulator may not have volume capacity of a bladder accumulator. A schematic of a diaphragm accumulator is shown in Figure 2. http://www.machinerylubrication.com/articles/200907/pg26b.gif Figure http://www.machinerylubrication.com/articles/200907/pg26b.gif The behaviour characteristics of a diaphragm accumulator are similar to a bag accumulator and have the same advantages and disadvantages. However a diaphragm accumulator may be spherical or cylindrical (or possibly other shapes) which may be an advantage in some installations. The main difference with bladder accumulators is an increased maximum compressions ratio (maximum system pressure to pre-charge pressure) of approximately 8 to 1. Piston Accumulator A gas piston accumulator is shown in Figure 3. A gas piston accumulator has a piston which slides against the accumulator housing on seals. On one side of the piston is nitrogen and on the other side is the hydraulic fluid and connection to the system. A fill port allows pressurization of the nitrogen. Accumulator, Piston Type Figure http://www.tobul.com/index.php?option=com_contenttask=viewid=13Itemid=27 A gas piston accumulator will not respond to transient pressures as fast as a bladder accumulator due to the mass of the piston (frequency characteristics depend on piston mass and spring characteristics of the nitrogen). However, a piston accumulator will have better damping due to hydraulic leakage (viscous damping) and friction between the piston and housing (coulomb friction seal friction). Piston accumulators may also be more prone to leakage than other types of accumulators due to the seals. Piston accumulators will generally provide higher flow rates than gas accumulators for equal accumulator volumes. This is because piston accumulators can accommodate higher pressure ratios (maximum system pressure to pre-charge pressure) than gas accumulators, up to 10 to 1, compared with bladder accumulator ratios of 4 to 1. The disadvantages of piston accumulators are that they are more susceptible to fluid contamination, have a lower response time than bladder (unless the piston accumulator is at a very high pressure) and will have hysteresis from the seal friction. The pre-charge for a gas piston accumulator is typically set to around 90% of minimum desired hydraulic system pressure. A schematic of a spring piston accumulator is shown in Figure Accumulator, Spring Type In a spring accumulator, the spring applies a force to a piston which compresses (or pressurizes) the fluid in the accumulator. As normal system pressure, the spring will be fully compressed. As system flow demands exceed the pump capacity, the spring will extend pushing the piston which in turn pushes fluid into the adjoining pipe. Hence the accumulator supplements pump flow. The maximum response time of the accumulator is set by the natural frequency, which is computed using Metal bellows accumulators are used where a fast response time is not critical yet reliability is important. Emergency brake accumulators are a good application for metal bellows accumulators. The metal bellows accumulator consists of a pressure vessel with a metal bellows assembly separating fluid and nitrogen. The accumulator is similar to a piston accumulator, except a metal bellows replaces piston and piston seals. Metal bellows accumulators are very reliable and long life components, and have a proven service history. Metal bellows accumulators are pre-charged by supplier and then permanently sealed leading to a maintenance free accumulator. Metal bellows accumulators will be slow in responding to pressure changes due to increased mass of piston and bellows. The advantages to the metal bellows type include exceptionally low spring rate, allowing the gas charge to do all the work with little change in pressure from full to empty, and a long stroke relative to solid (empty) height, which gives maximum storage volume for a given container size. The welded metal bellows accumulator provides an exceptionally high level of accumulator performance, and can be produced with a broad spectrum of alloys resulting in a broad range of fluid compatibility. Another advantage to this type is that it does not face issues with high pressure operation, thus allowing more energy storage capacity. Applications of Accumulators to KERS One of the main applications of hydraulic accumulators is storing energy. Hydro-pneumatic accumulators incorporate a gas in conjunction with a hydraulic fluid. The fluid has little dynamic power storage qualities. The fluid can only be reduced a small amount in volume even under high pressure. Therefore when only a small amount of the total contained volume is released, the pressure of the remaining fluid in the system will drop to zero. However, the relative incompressibility of a hydraulic fluid makes it ideal for fluid power systems and provides quick response to power demand. The gas, however working with the hydraulic fluid in the accumulator, can be compressed to high pressures and low volumes. Potential energy is stored in this compressed gas to be released upon demand. In the piston type accumulator the energy in the compressed gas exerts pressure against the piston separating the gas and hydraulic fluid. The piston in turn forces the fluid from the cylinder into the system a nd to the location where useful work will be accomplished. On this basis, with respect to all the types of accumulator a hydro-pneumatic accumulator would be ideal for storing the energy taken out of a bike whilst braking.. Of course the loss of pressurized gas in a sealed accumulator is a failure critical to safety when it plays such an important role as braking. A team of engineering students from university of Michigan undertook a project to use a hydro-pneumatic regenerative braking on a bicycle. It was a redevelopment of a heavier previous attempt to make a working prototype to fit within a 29 front wheel. They use a 0.5L accumulator and believed this to be sufficient in storing the required energy at a maximum working system pressure of 5000psi. They failed to test and thus supply conclusive results for the performance characteristics but through theoretical analysis they prescribe the key parameters fig. Figure Its weight is clearly impractical as it weighs almost as much as a conventional bike at 13kg. In terms of weight of a bicycle with respect to saving weight, it is more important to have lighter wheels than a lighter bike frame. This is because the rolling resistance is applied at the wheels although it carries half the overall weight of bike and rider a lighter wheel makes it easier to initially start a bike. Based on the team from michigans ( ) the following calculations outline the practicality of implementing a hydraulic KERS. Firstly for a hydraulic system to be implemented the storage must be addressed the capacity must be determined and pressures needed to store the kinetic energy. A bike braking from 20mph requires 5000J of energy to power. From Parkers website a manufacture of accumulator and motors parkers rate the ACP series accumulators at max pressure 5000psi, if assuming A hydraulic KERS must use a hydraulic motor to provide enough torque to drive the bike as well as provide enough resistive torque to be an effective brake. A bicycle travelling at 20mph on 26 wheels spins the motor through 18:1 gear ratio of the pump gear train which then spins the motor 4632rpm, corresponding to 4.52 N-m torques at 3000 psi. This translates to a braking torque of about 81.36 N-m applied to the main gear due to the 18:1 gear ratio. From this brake torque is an effective brake On release of pressure fully charged 5000 psi accumulator generates 7.57 N-m of torques. The 14:1 gear ratio of the motor gear train applies a 105 N-m torque to the main bicycle cluster gear. 7.57 N-m corresponds to around 800 rpm from its torque rpm curve, which turns the main gear at around 57 rpm due to the 14:1 gear ratio. This torque from fig can propel a bike at Conclusion The accumulator doesnt need to be an excessively large capacity to release enough energy to propel a bike 20mph, upon releasing the energy at a pre-charge of 3200psi. But a larger accumulator is needed for the accumulator to give more than one bursts using its full capacity. A hydraulic motor can produce 81.36N-m braking torque which is an effective brake. Furthermore an accumulator can power a hydraulic motor provide an accelerating torque to propel a bicycle. However based on the weight of the design from univerty of Michigan their prototype was 13kg, they used two accumulators plus they attached it to a bracket that probably contributed to the majority of the weight.

History of Fireworks :: Chine Fireworks Explosives Essays

History of Fireworks The birthplace of fireworks is generally recognized as China, with the first explosive mixture found being black powder, during the Sung dynasty ( 960-1279 ). It is said that a cook in ancient china found that a mixture of sulfur, saltpeter, and charcoal was very flammable and would explode if enclosed in a small space. The first application of this technology was for entertainment. The Chinese are still the leader in the production of fireworks. Once the recipe for black powder was perfected, they found that it was easily used as rocket fuel, and they made hand carved wooden rockets in the shape of a dragon, in the sixth century. These rockets shot rocket powered arrows from their mouth, and were used against the Mongol invaders of 1279. The principle behind these rockets is still used in rocket powered fireworks today. Through adventurous explorers, the knowledge of making fireworks spread west, through Arabia in the seventh century. The Arabs called the rockets Chinese arrows. The Mongols are credited with taking Chinese rockets and gunpowder to Europe around 1241. The first record of their use in Europe are around 1258. Until the 19th century, fireworks lacked a major aesthetically essential characteristic: color. Pyrotechnicians began to use a combination of potassium chlorate and various metallic salts to make brilliant colors. The salts of these metals produce the different colors: strontium burns red; copper makes blue; barium glows green; and sodium, yellow. Magnesium, aluminum, and titanium were found to give off white sparkles or a flash. Even though China invented the fireworks, Europe surpassed them in pyrotechnic development in the 14th century, which coincides with the time the gun was invented. Shot and gunpowder for military use was made by skilled tradesmen, later called firemakers, who also made fireworks for peace or victory celebrations. During the Renaissance, two European schools of pyrotechnic thought emerged: one in Italy and the other at Nuremberg, Germany. The Italian school of pyrotechnics emphasized elaborate fireworks, and the German school stressed scientific advancement. Both schools added significantly to further development of pyrotechnics, and by the mid-17th century fireworks were used for entertainment on an unprecedented scale in Europe, being popular even at resorts and public gardens. In the mid-19th century fireworks became popular in the United States. Injuries associated with fireworks, particularly to children, eventually discouraged their unrestricted use. As a result, in many states of the U.