Transducers used in the Cardiac Ultrasound Machine.

Transducers used in the Cardiac Ultrasound Machine. Transducers used in the Cardiac Ultrasound Machine. Abstract: Ultrasound imaging depends on the ability of piezoelectric crystals to generate sound when excited with alternating current and the reverse effect of charge accumulation or current flow when such crystals are subjected to pressure from sound waves. The first known ultrasound imaging machine was designed by K. T. Dussik in Australia in 1937. However, despite its widespread acceptance today, medical ultrasound did not develop as rapidly as X-ray imaging. Despite the relatively slow start, medical ultrasound imaging is very widely accepted today because there is no ionising radiation involved and hence the procedure is relatively safe. Ultrasound equipment is also cheaper as compared to X-ray imaging, magnetic resonance imaging, MRI and other techniques associated with nuclear medicine. The procedure involves minimal patient discomfort and is very useful for examining the soft tissues or the developing foetus. A dramatic increase in the number of older patients with chronic he art and valve disease has resulted in a prolific demand for the ultrasound cardiac imaging machines which can satisfy the requirements associated with fast and cost effective measurement of cardiac anatomy or function. One of the critical elements in the medical ultrasound imaging system is the ultrasound transducer without which signal processing and visualisation of the soft tissue images is impossible. Although many naturally occurring substances such as quartz exhibit the piezoelectric effect, lead zirconate titanate (PZT) ceramic ferroelectric materials have for many years been used for biomedical applications because of their superior characteristics for soft tissue imaging.   Polyvinylidene difluoride (PVDF), transducer material has demonstrated advantages as a high frequency receiver. Single or multilayer transducers made of these elements can be used for ultrasound imaging as single transducers operating in A-mode or a two or three dimensional transducer array for B-mode, C-mode or M-mode ultrasound imaging. This brief essay takes a look at transducers for medical ultrasound. The principle of operation of a cardiac ultrasound imaging device is based on the information that is provided by the varying delay times of echoes that are reflected from various depths of the human body tissue as a result of the ultrasound pulses that are generated by an ultrasound transducer being incident on the body tissue. Delay times of echoes from different depths are different and ultrasound is reflected from the interface of different types of tissues. A Doppler shift in frequency is also generated as a result of moving objects and the attenuation of ultrasound waves depends on the type of tissue that the ultrasound wave is travelling through. The ultrasound transducer which is responsible for the generation and detection of reflected ultrasound is, therefore, an essential component of the ultrasound imaging device. Ultrasound transducers work on the basis of the piezoelectric effect in which an alternating voltage applied to piezoelectric crystal material causes the crysta ls to become electrically polarised as a result of the applied electric field and hence vibrate with the alternating voltage to produce sound. Such crystals also become electrically polarised when stress is applied to them and hence any sound waves which are incident on them result in charge accumulation on the crystal surface and hence the generation of an alternating voltage. Thus, an ultrasound transducer consists of a suitable piezoelectric material sandwiched between electrodes that are used to provide a fluctuating electric field when the transducer is required to generate ultrasound. When the transducer is required to detect ultrasound, the electrodes may be used to detect any fluctuating voltages produced as a result of the polarisation of the crystals of the piezoelectric material in response to incident sound which generates fluctuating mechanical stresses on the material. Piezoelectric materials include quartz, ferroelectric crystals such as tourmaline and Rochelle salt a s well as the group of materials known as the piezoelectric ceramics, which include lead titanate (PbTiO3) and lead zirconate (PbZrO3). These materials are also known as piezoelectric ceramics which are used in ultrasound transducers for biomedical applications.Polyvinylidene difluoride (PVDF) is another transducer material which has demonstrated advantages as a high frequency receiver. Piezoelectric ceramics are sold with the brand name PXE by Philips Company and are solid solutions of lead titanate (PbTiO3), and lead zirconate (PbZrO3) which have been modified by additives which are a group of piezoelectric ceramics known as PZT. PXE materials are hard, chemically inert and unaffected by a humid environment. The crystals in a ferroelectric material of which PXE is made up of align themselves randomly in a number of directions. With such a random orientation of crystals, the material will exhibit no piezoelectric effect. In order to have a piezoelectric material which is capable of being used for ultrasound transducers, the material has to be subjected to a strong electric field at high temperatures. This has the effect of permanently locking the crystals in the direction of the applied electric field and making the crystal piezoelectric in the direction of the electric field. Hence, a piezoelectric ceramic material may be converted into a piezoelectric material in any given direction by applying a strong electric field to the material in the given direction at an elevated temperature. This treatment, which is known as poling, is the final stage in the manufacture of a PXE piezoelectric. Metal electrodes perpendicular to the poling axis are deposited on the material so that an alternating electric field may be applied to generate ultrasound or ultrasound vibrations may be sensed by sensing the electric field across the piezoelectric material. The voltage across a piezoelectric ceramic PXE material is usually directly proportional to the applied stress. The construction of a simple, single element piezoelectric transducer is as shown below. The Construction of a Single Element Piezoelectric Transducer Ultrasound imaging in the A-mode directs a narrow beam of ultrasound into the tissue being scanned and the echo which may be displayed on a CRT screen provides a measure of the distance between reflecting surfaces in the body. In the B-scan mode, the echo signal is brightness modulated which makes it possible for information related to tissue depth to be displayed on the screen in a visually effective manner. An ultrasound transducer array operating in B-mode permits a picture of the tissues within a patient’s body to be displayed on a CRT device. M-mode ultrasound imaging presents tissue movement by scanning an A or B – line on a monitor as a function of time and movements in this line indicate movements in the tissues within the body. In C-mode ultrasound imaging a second transducer is used to detect echoes sent out by the first transducer, presenting a 2-D map of the ultrasound attenuation within tissues. Having discussed the principles of operation of a piezoelectric medical ultrasound transducer, it is now appropriate to consider the practical problems associated with the construction of such transducers. This is done below. The Design of Ultrasound Transducers A transducer which is constructed out of piezoelectric material will have a natural frequency of resonance and it is appropriate that the transducer should be excited with alternating electric field which matches the natural resonant frequency of oscillation of the material. The ultrasound frequencies that are used in medical imaging applications range from 1 MHz to 15 MHz and echocardiography is usually performed at frequencies of 2.5 MHz. Hence, transducers which are used for ultrasound imaging have to be tuned for different frequencies. For a transducer material in which ultrasound waves travel at the speed c, with a resonant frequency f, the thickness of the material is related by the formula f=c/2d. Hence, it is possible to tune various transducers constructed of the same material to different frequencies by adjusting the thickness of the material. The ultrasound transducer can be excited by a continuous wave, a pulsed wave, or a single voltage pulse depending on the requirement s for observing a continuous image, echo ranging or other tissue measurements. The rear face of the piezoelectric crystal material is usually supported by a backing material which is tungsten loaded araldite, so that the vibrations in the piezoelectric material are rapidly damped after the initial excitation. It is important to couple the piezoelectric transducer to the body of a patient so that the incident ultrasound energy can be effectively transmitted into the body tissue that is being scanned. In order to do this, matching layers of suitable acoustic material are used along with a gel which makes it possible for the ultrasound waves to penetrate the tissue more efficiently. As far as possible, the characteristic acoustic impedance of the tissue being scanned is matched with the acoustic impedance of the transducer. The characteristic acoustic impedance of the tissue is defined as: In the formula, c is the speed of ultrasound in human tissue which is about 1540 m/sec with a variation of +/- 6% and   is the tissue density. K is the bulk elastic modulus of the tissue being scanned. The acoustic parameters of an ultrasound transducer include its nominal frequency, the peak frequency which is the highest frequency response measured from the frequency spectrum, the bandwidth of the transducer which is the difference between the highest and the lowest – 6 dB level in the frequency spectrum, the pulse width response time of the transducer, which is the time duration of the time domain envelope which is 20 dB above the rising and decaying cycles of a transducer response, the loop sensitivity for a medium on which a test is performed which is characterised by: Here, Vo is the excitation pulse voltage in volts, while Vx is the received signal voltage from the transducer.   The signal to noise ratio for a biomedical ultrasound transducer is also an important parameter for an ultrasound transducer and this is defined as: In the above expression, Vx is the received signal voltage from the transducer in volts in response to a specified tone burst or pulse and Vn is the noise floor in volts. The signal to noise ratio for an ultrasound transducer is a measure of the noise associated with the transducer, measuring instrument or cables and this is a good measure of how sensitive a transducer is. In addition to the previously mentioned parameters, geometrical parameters for a transducer describe how the acoustic pressure generated by a transducer varies across the axial and cross-sectional fields of a transducer. These variations are illustrated below: Axial Beam Profile for an Ultrasound Transducer Cross – Sectional Beam Profile for an Ultrasound Transducer he detailed construction of an ultrasound transducer for medical applications involving the shaping of the piezoelectric material, matching layers, housing and backing materials etc is presently conducted using computational techniques such as Finite Element Modelling of ultrasound transducers through the use of software packages such as Ultrasim and other commercially available software. In the overall design, efforts have to be made to ensure that the overall design will be optimised so as to deliver a sufficiently high power of ultrasound into the tissue being imaged and as far as possible there is best possible sound impedance matching between the transducer and the scanned tissue. Design of the backing material in an ultrasound transducer is important because this design determines the ring down time of the transducer, which is critical for low noise and optimal axial resolution of the transducer. Trends in Transducer Design for Echocardiography Only the simplest equipment for echocardiography will use a single ultrasound transducer and there is a trend towards design of echocardiography equipment which uses two or even three dimensional arrays of ultrasound transducers to provide superior quality 2 –D or 3-D computer generated pictures of the organ being imaged.   Even the relatively simpler equipment being used these days has two or more ultrasound transducers fitted into the transducer probe. The array of transducers are capable of generating a shaped beam of ultrasound which can be appropriately focused using electronic digital signal processing techniques to provide better images and resolution. Although the relatively simple medical ultrasound scanners cost about  £1000 per piece, reasonably decent transducer assemblies for a decent Philips or Toshiba ultrasound machines can cost  £1500 for the transducer alone. Transducer arrays for two or three dimensional ultrasound imaging equipment can be much more ex pensive because of the large number of transducers that are employed in such imaging equipment.   For better quality ultrasonic imaging to be possible, there is a requirement for enhanced bandwidth transducers, higher frequency transducer arrays and sophisticated digital signal processing circuits. There is also a trend towards transducer miniaturisation which will make intracavitary, intraurethral, or intravascular ultrasound (IVUS) investigation possible. The current imaging frequency range of 1 MHz to 15 MHz is expected to be increased to 20 MHz to 100 MHz and at these frequencies, microsonography devices using miniature ultrasound transducers with higher sensitivities are expected to provide much better and higher resolution images using catheter based transducers which are less then 2mm in diameter and are capable of being placed in veins.   New ultrasound transducer materials are likely to provide transducers which are far more sensitive then those available presently and consume lower power. These transducers can be operated from battery powered portable equipment and th ere are indications in literature that with the availability of such devices, it is likely that the stethoscope will be replaced by miniature ultrasound equipment. New trends in ultrasound transducer construction are also moving towards composite transducer construction in which a composite of two piezoelectric materials is used to design the transducer. Ultrasound transducers are fairly rugged and the piezoelectric material does not loose its properties unless exposed to high temperatures approaching the Curie temperature for the material are reached or there are strong alternating or direct electrical fields opposing the direction of poling for the material. Mechanical stresses imposed on the piezoelectric materials should not exceed the specified limits and although the specified limits vary for different types of materials, mechanical stress in excess of 2.5 MPa may be considered as likely to cause permanent damage. Ultrasound transducers are capable of being designed to operate in liquid mediums and the piezoelectric material does not react with water or gel.   Conclusion Materials with piezoelectric properties such as lead titanate (PbTiO3) and lead zirconate (PbZrO3) lend themselves to being treated by poling to generate as well as detect ultrasound waves when subjected to alternating electric fields or mechanical stresses. Ultrasound transducers can be made out of these materials and these transducers can be designed for specified resonance frequencies for use in medical imaging. The detailed design of such transducers is an exciting and involving undertaking which is capable of being assisted by finite element simulations. Advances in transducer design involving the use of new materials, miniaturisation and the use of arrays of transducers promises to revolutionise medical imaging in the future by providing high resolution 3-D ultrasound images and the field is full of promise for device designers as well as computer engineers of the future. References/ Bibliography Web Sources   Abboud, Najib N et al. â€Å"Finite Element Modelling for Ultrasonic Transducers†. Weidlinger Associates Inc. SPIE Int. Symp. Medical Imaging 1998, San Diego, Feb 21-27, 1998. 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Jane Eyre: An Unconventional Heroine Essay

‘Ms. Eyre is one of those heroines who refuse to blend into the traditional female position of subservience and who stand up for her beliefs’ Explore how the female position is presented. Jane Eyre was written by Charlotte Bronte and was first published in 1847 in the Victorian era. During this period, women were expected to remain at home and their time was to be spent taking care of household duties and their children. Females were regarded as properties rather than as humans: they either belonged to their fathers or their husbands. As they were believed to be incapable of surviving on their own, they had no independence. Permission was required for almost everything and they were expected to abide by rules set out by their owners. Men were considered to be very much superior to women and they were to be treated with respect by the latter, whether they agreed with their views or not. In general terms, society’s portrayal of a conventional woman was very different to what it is now, so it is not surprising that modern readers may find their attitudes as shocking. Although Jane Eyre was written during this period, Bronte portrays her character in a very unconventional way, following the trends of the Gothic genre. The character of Jane is used to mainly challenge the Victorian attitudes towards women, religion and class. The fact that Bronte chooses a female character to portray her views is surprising to the Victorian reader. During that period, inequality between the genders prevented the views of females from being expressed, and if expressed, they were not regarded with respect. Expressing their ideas in any way was extremely unconventional as it would have been shocking for a woman to be passionate. By using Jane as a device to put forward her views, Bronte challenges the idea that women did not have views worth considering. Jane is a character who is sure of herself and her behaviour is described as â€Å"a picture of passion.† However, the reader cannot deny she is very intelligent and that she has a very good judgement of character. Jane’s uniqueness is detectable from the start. Even as a child, she is different from her cousins at Gateshead. Instead of taking pleasure in playing, she prefers reading books such as â€Å"Goldsmith’s History of Rome† and â€Å"Gulliver’s Travels† and forming opinions on the characters involved. Jane has a strong wish to travel and see the lands that she reads about, showing that â€Å"women feel just as men feel.† Here Bronte uses Jane to present the idea that women are capable of being intelligent; that they can form right judgements and that they have ambitions and dreams, just as men do. This idea is reinforced throughout the novel, especially when it comes to religion. Bronte makes the character of Jane Eyre stand up for her beliefs by challenge the views of men. She uses this character to challenge different ideas about religion. Mr Brocklehurst, the headmaster of Lowood Institution (her second home), represents the hypocrisy in the Evangelical Movement and the forceful authority of men. When referring to his students, he feels the need â€Å"not to accustom them to habits of luxury and indulgence,† but to encourage â€Å"spiritual edification to the pupils† by making them suffer â€Å"temporary privation,† contradicting his own luxurious lifestyle. Jane emphasises the ridiculous in his portrayal and his concepts on religion are mocked through the depiction of his hypocritical sermons, suggesting that this interpretation of Christianity must not be taken seriously. Brocklehurst fails to influence the beliefs of Jane, and in some ways, her friend Helen Burns. This character conveys a different concept: one of endurance and peace mainly based on the New Testament idea of â€Å"loving those who hate you.† Once again, Jane is not satisfied with this interpretation of religion and insists that she should â€Å"resist those who punish me unjustly.† The third interpretation of religion is represented by St John Rivers, who believes in sacrificing emotional needs for Christianity, which Jane also rejects (by rejecting his proposal). Bronte makes Jane Eyre reject the ideas imposed by male characters, emphasising her controversialist personality. Jane forms a more reasonable and agreeable interpretation of religion than male characters, and Helen in not influenced by Mr Brocklehurst’s cruelty. Bronte proposes another interpretation through this character: that religion does not require you to deny yourself completely; that it can be used as a guide in circumstances beyond human control. By doing this, Bronte shows that females have the ability to form their own opinions on complex ideas, such as religion and that they can form them independently even under the pressure of forceful authority. The idea that woman are capable of being independent is established when she opposes Mr Rochester’s efforts to â€Å"make the world acknowledge you a beauty† by pointing out that she will not be herself if he succeeds, â€Å"but an ape in a harlequin’s jacket.† Here Jane is refusing to be objectified and changed even by the man she loves. Bronte presents an independent woman who is sure of herself, and who wants to retain her individuality at any cost. Although Jane is a governess, she makes it clear that Mr Rochester doesn’t â€Å"have a right to command† her and that she is equal to him in many ways. Also, Jane maintains her dignity by refusing to marry Mr Rochester. Bronte shows that women are capable of being respectable and that they are not always lead by their emotions. This causes Jane to take courage and leave Mr Rochester, disregarding the Victorian idea that women should do as men wish. While it could be argued that Jane surrenders to the Victorian expectations by returning to Mr Rochester, it is clear that she is not returning to him because she cannot survive on her own. Circumstances change, making Jane rich. She returns to Mr Rochester as an equal in every way (whereas previously she was aware of their social difference), and she returns for love more than anything else. Besides Jane, Bronte uses the characters of Miss Temple and Diana and Mary Rivers to portray that women are not inferior to men. The mentioned characters influence Jane and are involved in the development of her character as an â€Å"independent woman,† as she calls herself by the end. Miss Temple is her role model and helps her to realise that she does not have to give in to forced authority; that she must stand up for what is right. In many ways, Miss Temple gives Jane courage for the future. She goes against Mr Brocklehurst’s orders and sympathises with the girls who are treated cruelly. Apart from feeling differently to him, she takes action by giving the girls â€Å"a lunch, consisting of bread and cheese, twice† and fearlessly takes responsibility for it. She is also used represent what Bronte believes to be the true interpretation of Christianity, mainly by giving her a strong sense of injustice in the running of Lowood Institution. While Miss Temple inspires Jane to become independent and to be just, Mary and Diana Rivers inspire Jane to improve her knowledge and to become more intelligent. Jane â€Å"followed in the path of knowledge they had trodden before me,† suggesting that she wants to become as knowledgeable and accomplished. The fact that Bronte chooses Jane to be inspired by female characters reinforces the points that women can be intelligent and independent, and at the same time inspire others to become better people. While some characters are used to represent what women should be, Bronte creates a sharp contrast between the character of Jane Eyre and other female characters in the novel to challenge Victorian the concept of the conventional woman. Women of that time were only valued for their appearance, social and economic status. In many ways, Blanche Ingram (the woman whom Jane believed Mr Rochester loved) represents the ideal woman of the Victorian era. She is beautiful, wealthy and had a well reputed family, contrasting with Jane, who is (in her own words) â€Å"poor, obscure, plain, and little.† However, while the Victorian reader might be inclined to admire Blanche more than Jane, Jane feels that â€Å"Miss Ingram†¦was too inferior to excite the feeling† of jealousy because â€Å"she had a fine person† but â€Å"she was not genuine†¦her mind was poor.† The modern reader can spot that Jane, in contrast to Blanche is very intelligent, she has self worth and that she speaks her mind. Jane can also analyse one’s character rather accurately, (as proved by Blanches’ rejection of Mr Rochester after she learns of his inferior economic status). Bronte is stressing that women must be admired for their character rather than their outward beauty; that appearances can deceive and that women are worth more than social or economic status. Another contrast is formed between Jane and Bessie, the maid at Gateshead. While Jane rebels against the cruelty of her aunt, Bessie advices her to â€Å"make yourself agreeable to them.† Bessie is used to represent Victorian women who give in to the expectations, while Jane represents the idea that women can express their views and stand up for themselves. While some may argue that Jane is a rebellious character, it is clear that she has control of her emotions, unlike Bertha, who lets her rage out (even though it is beyond her control). By using the character of Jane Eyre, Bronte presents a woman who is capable of being intelligent, independent, dignified and confident about her opinions even though she is not very attractive or wealthy. She uses this character to challenge some of the Victorian concepts concerning women and their positions, as well as to convey her less major themes about religion and class. In some passages, Bronte addresses these issues directly (in the conversation about Mr Rochester and Jane being equals) while she uses more subtle methods in other situations (while describing Blanche). Bronte takes care not to make Jane a perfect person, but she incorporates flaws to allow readers to relate to her. She also uses other female characters to reinforce her points, by showing the qualities of some as well as showing the flaws in others. By doing so, Bronte shows that women can be equal to men, not only in intelligence, but in actions as well. She also portrays different types of women: some who give in to the expectations of society, and some who stand up for their own beliefs. She outlines what she thinks a woman’s qualities should be and she encourages women to stand up their rights. Bronte successfully puts forward her points and she makes the reader understand her ideas by the portrayal of her characters, mainly females.

Born-Haber Process Lab

Chemistry Lab: Haber’s Process (A Computer Simulation) Cherno Okafor Mr. Huang SCH4U7 October 8th, 2012 Introduction The Haber process is the process by which ammonia (NH3) is produced. The equation for this reaction is†¦ The symbol shown in the middle means it is a reversible reaction so the product can decompose back into the reactants. Therefore, optimum conditions must be selected to get the greatest yield. When the forward and backward reactions are the same, it is said to be in a state of dynamic equilibrium.The position of this dynamic equilibrium can be moved forward by changing the conditions the reaction is done in. This follows Le Chatelier’s Principle which says changes to a system in equilibrium will move it in an opposite direction. Condition (Dependent Variables)| Effect (Independent Variables)-Yield, Equilibrium Time, Net Profit| Pressure| Increasing this will improve the yield because the forward reaction reduces pressure. However, putting up the p ressure too far is impractical and becomes too expensive. Temperature| A higher yield can be obtained by using a low temperature since the forward reaction produces heat, but this also will make the reaction slower, and less profitable. | Catalyst| The Haber process makes use of catalysts like iron, tungsten, and platinum to speed up the reaction, however this does not improve the yield. | Note: The conditions of the Haber process must be finely balanced to reach a combination of highest yield and fastest reaction, this is very important because getting this right will make sure this industrial process is as profitable as possible.Data Collection and Processing (Raw Data): Variables| Results (No Catalyst)| Results (No Catalyst)| Results (No Catalyst)| Results (No Catalyst)| Results (No Catalyst)| Temperature ( °C)| 658| 660| 663| 677| 680| Pressure (Atm. )| 464| 482| 510| 658| 694| Time to Equilibrate (Min)| 10. 16| 10. 17| 10. 17| 10. 15| 10. 15| Yield (%) | 15. 8| 16. 3| 17. 1| 21. 2| 22. 2| Amount ($) per day| 36,454. 36| 36,413. 56 | 36,380. 36 | 36, 361. 71| 36,321. 0| RESULTS: * After this first trial using no catalysts, it is evident that the equilibrium time is extremely slow and unfortunately, only produces a small yield yet with a large amount of net profit per day. * Another thing was the temperature. The net profit and yield seemed to be at its highest when the temperatures were set at around the 600-700 °C range. With an extremely low temperature though, the time to equilibrate was close to a million years, so temperature had to be fairly high * In terms of the pressure, it had to be between the 400-700 Atm. ange (not too high so that it would yield a high cost and not too low so that it would yield a low percentage and net profit) but just in the middle * I wanted to find balance in my profit and yield, so with no catalyst, I adjusted the bars so that the temperature value was fairly close to the pressure value and the results were a greater net profit, with a reasonable equilibrium time of reaction Variables| Results (With Iron Catalyst) | Results (With Iron Catalyst)| Results (With Iron Catalyst)| Results (With Iron Catalyst)| Results (With Iron Catalyst)| Temperature ( °C)| 468| 475| 472| 473| 479| Pressure (Atm. | 721| 881| 809| 832| 989| Time to Equilibrate (Min)| 10. 18| 10. 16| 10. 17| 10. 16| 10. 18| Yield (%) | 58. 8| 63. 9| 61. 7| 62. 4| 66. 9| Amount ($) per day| 33, 793. 48| 33, 909. 39| 33, 805. 15| 33,893. 81| 33, 753. 80| RESULTS: * After this second trial, I used the catalyst of iron. Iron was by far the most profitable catalyst to use as it was not that expensive as the others (Tungsten and Platinum), and it produced a high yield with a pretty high amount as well * In terms of the temperature, it was a very typical 400-500 °C range which is also a very high temperature and the yield of ammonia would be high and my net profit as well. For pressure, I increased its value to the 700-900atm range and th is in conjunction with my high temperature range produced the best results as I produced high yields from 50-70% with the exact same time frame it took for the non-catalyst reaction to equilibrate * So obviously with the addition of the iron catalyst, I did not have to take more or less time for the equilibrium reaction to take place, I instead produced a higher yield of ammonia with a fairly large net profit, which was my goal in the first place Variables| Results (With Tungsten Catalyst)| Results (With Tungsten Catalyst)| Temperature ( °C)| 429| 435|Pressure (Atm. )| 346| 418| Time to Equilibrate (Min)| 10. 46| 10. 16| Yield (%) | 50. 4| 49. 9| Amount ($) per day| 19, 506. 24| 19, 495. 86| RESULTS: * Finally, for this last third trial, I used Tungsten catalyst. This Tungsten catalyst was not as efficient as the iron catalyst, and it also cost more. * In terms of temperature, the 400-450 °C range which was average because increasing the temperature would have created more econo mic problems such as higher costs of energy/production, etc. With iron, it was fairly easy to play around with the temperature, but for Tungsten it was more challenging. I also had to lower the pressures, but not too low so that the equilibrium time would be slow, but not too high either so that I would be losing a lot of profit because of the economic costs * As a result, this adjustments yielded only a little less than what I yielded with iron, however still a fairly high yield. The only decrease was in the net profit, because of the expenses of Tungsten. * The Temperature-Equilibrium Considerations: * One must shift the position of the equilibrium as far as possible to the right in order to produce the maximum possible amount of ammonia in the equilibrium mixture.The forward reaction of the production of ammonia is exothermic. Therefore according to Le Chatelier’s Principle, this will be favoured if one lowers the temperature. The system will respond by moving the position of equilibrium to counteract this-producing more heat. In order to get as much ammonia as possible in the equilibrium mixture, one needs as low a temperature as possible. * The Temperature-Rate Considerations: * The lower the temperature one uses, the slower the reaction becomes. In this case though as a manufacturer, I am trying to produce as much ammonia as possible per day.It makes no sense to try and achieve an equilibrium mixture which contains a very high proportion of ammonia if it takes several years for the reaction to reach that equilibrium. Therefore, one needs the gases to reach equilibrium within the very short time that they will be in contact with the catalyst (or without) in the reactor. * During my experiment lab, I noticed that the temperature range of 400-700 °C is a compromise temperature, producing a reasonably high proportion of ammonia in the equilibrium mixture, but also in a very short time. * The Pressure-Equilibrium Considerations:There are only 4 molec ules on the left-hand side of the equation, but only 2 on the right. According to Le Chatelier’s Principle, if you increase the pressure the system will respond by favouring the reaction which produces fewer molecules. That will cause the pressure to fall again. In order to get as much ammonia as possible in the equilibrium mixture, one needs as high a pressure as possible. * The Pressure-Rate Considerations: * Increasing the pressure brings the molecules closer together. In this particular instance, it will increase their chances of hitting and sticking to the surface of the catalyst where they can react.The higher the pressure, the better in terms of the rate of a gas reaction. * Economic Considerations: * Very high pressures are extremely expensive to produce on two accounts: * One has to build extremely strong pipes to withstand the very high pressure. * Also, high pressures cost a lot to produce and even maintain. That means that the running costs of your manufacture are very high for you. * During my lab, I noticed that 200 atm is a reasonable choice of pressure. If the pressure used is too high however, the cost of generating it exceeds the price you can get for the extra ammonia produced. The Catalyst-Equilibrium Considerations: * The Catalyst actually has no affect whatsoever on the position of the equilibrium. Adding a catalyst does not produce any greater percentage of ammonia in the equilibrium mixture. Its only function is to speed up the reaction. * The Catalyst-Rate Considerations: * In the absence of a catalyst, the reaction is so slow that virtually no reaction happens in any sensible time. The catalyst ensures that the reaction is fast enough for a dynamic equilibrium to be set up within the very short time that the gases are actually in the reactor.Conclusion: To sum up, the objective of this computer simulation lab was to produce a high yield of ammonia with as high a net profit as possible, while considering the economic factors suc h as energy cost, and production cost, and even catalyst costs. It turned out that I was prohibited from using platinum as a catalyst because it was too expensive. Out of the remaining catalysts: Iron, and Tungsten, Iron was the most efficient and profitable one as it is less expensive and yielded a great amount of ammonia while I was able to make a large profit as well.The Tungsten catalyst did yield a fairly high amount of ammonia, however not a very high net profit was made from it and this is again due to the economic implications of energy and production as mentioned. When I did not use any catalysts, the problem was that the time to equilibrate the reactions was atrocious, and very slow. With the criteria â€Å"highest yield and fastest reaction† in mind, the most optimal combination to produce ammonia was the 400-500 °C (479 °C) temperature range, with the 900-1000 Atm range (989atm). and along with the iron catalyst produced 66. % of ammonia, and at least $33, 000 in net profit. I chose this result as the best one because of the balance of the dependent variables of time, yield, and net profit. I could not find my way up to at least $34, 000 or above in net profit with the iron catalyst. I only managed to exceed that profit when I did not use any catalysts, but again the reaction time is way too slow and hence senseless. I probably could have kept on going to gradually adjust the temperature and pressure one by one to look for an even higher yield and net profit, but time is an issue and I would have to sit for a long time doing this.

RN to BSN Degree Labor and Delivery Nurses Care for Women, Families, and Newborns 2019

Labor and delivery nurses are one of the few groups of nurses that remain primarily in the hospital setting. Whereas many nursing disciplines are shifting out into to the community, labor and delivery nurses typically work in hospitals, clinics, and birthing centers. Nurses who have earned an RN to BSN degree are able to enter the field of labor and delivery to care for women and families throughout the birthing process. What is a Labor and Delivery Nurse? A graduate with an RN to BSN degree who chooses to work as a labor and delivery nurse cares for women who are having pregnancy complications, are in labor, or who have recently delivered. They also provide care for newborns and, along with other health care professionals, create a plan of care for the mother and her baby. Some labor and delivery nurses may work in the nursery or with the physician during a cesarean section. .u595826cf796794d03fdf80f9fa6c1a4d { padding:0px; margin: 0; padding-top:1em!important; padding-bottom:1em!important; width:100%; display: block; font-weight:bold; background-color:#eaeaea; border:0!important; border-left:4px solid #34495E!important; box-shadow: 0 1px 2px rgba(0, 0, 0, 0.17); -moz-box-shadow: 0 1px 2px rgba(0, 0, 0, 0.17); -o-box-shadow: 0 1px 2px rgba(0, 0, 0, 0.17); -webkit-box-shadow: 0 1px 2px rgba(0, 0, 0, 0.17); text-decoration:none; } .u595826cf796794d03fdf80f9fa6c1a4d:active, .u595826cf796794d03fdf80f9fa6c1a4d:hover { opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; text-decoration:none; } .u595826cf796794d03fdf80f9fa6c1a4d { transition: background-color 250ms; webkit-transition: background-color 250ms; opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; } .u595826cf796794d03fdf80f9fa6c1a4d .ctaText { font-weight:bold; color:inherit; text-decoration:none; font-size: 16px; } .u595826cf796794d03fdf80f9fa6c1a4d .post Title { color:#000000; text-decoration: underline!important; font-size: 16px; } .u595826cf796794d03fdf80f9fa6c1a4d:hover .postTitle { text-decoration: underline!important; } READ 10 Job Tips for New GradsRequired Education to Become a Labor and Delivery Nurse Labor and delivery nurses must be licensed as Registered Nurses within the U.S. through a hospital diploma, associate degree, or RN to BSN degree. Many employers prefer to hire labor and delivery nurses who have earned a bachelor of science in nursing (BSN) and may require two years of prior medical-surgical experience. Labor and delivery nurses must also be certified in neonatal resuscitation and fetal monitoring. RN to BSN degree graduates who choose to work in labor and delivery nursing must possess good communication skills in order to work effectively with patients, families, and other health care professionals. They must also be able to prioritize patient needs and work effectively in a fast-paced environment. Related ArticlesBSN Degree Neonatal Nurses Care for Newborns with Special NeedsLPN RN Online Program Combine Business and Nursing for Advanced Career OpportunitiesHealth Care Employment OpportunitiesAccelerated BSN Program Forensic Geriatric Nurses Investigate Cases of Elder AbuseBSN Top 5 Reasons to Earn a Bachelor of Science in NursingA Nursing Shortage .u010421f553aeec5a361a40d730aa0a97 { padding:0px; margin: 0; padding-top:1em!important; padding-bottom:1em!important; width:100%; display: block; font-weight:bold; background-color:#eaeaea; border:0!important; border-left:4px solid #34495E!important; box-shadow: 0 1px 2px rgba(0, 0, 0, 0.17); -moz-box-shadow: 0 1px 2px rgba(0, 0, 0, 0.17); -o-box-shadow: 0 1px 2px rgba(0, 0, 0, 0.17); -webkit-box-shadow: 0 1px 2px rgba(0, 0, 0, 0.17); text-decoration:none; } .u010421f553aeec5a361a40d730aa0a97:active, .u010421f553aeec5a361a40d730aa0a97:hover { opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; text-decoration:no ne; } .u010421f553aeec5a361a40d730aa0a97 { transition: background-color 250ms; webkit-transition: background-color 250ms; opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; } .u010421f553aeec5a361a40d730aa0a97 .ctaText { font-weight:bold; color:inherit; text-decoration:none; font-size: 16px; } .u010421f553aeec5a361a40d730aa0a97 .postTitle { color:#000000; text-decoration: underline!important; font-size: 16px; } .u010421f553aeec5a361a40d730aa0a97:hover .postTitle { text-decoration: underline!important; } READ Managers and Management Training Through Example