Добірка наукової літератури з теми "SPINNING SHAFT"

The present work deals with the study of vibration and stability analysis of a functionally graded spinning shaft system using three-noded beam element based on the Timoshenko beam theory. Material properties are assumed to be graded in radial direction according to power law gradation. In the present analysis, the mixture of aluminum oxide (Al2O3) and stainless steel (SUS304) has been considered as functionally graded material where metal (SUS304) content decreases towards the outer diameter of the shaft. The functionally graded shafts has been modeled as a Timoshenko beam, which contains discrete isotropic rigid disks supported by flexible bearing. The functionally graded shaft has been modeled based on first-order shear deformation beam theory with transverse shear deformation, rotary inertia, gyroscopic effect, strain and kinetic energy of shafts by adopting three-dimensional constitutive relations. The derivation of governing equations of motion has been obtained using Hamilton’s principle. Three-noded beam element with four degrees of freedom per node has been used to solve the govering equations. In this work, the effects of both internal viscous and hysteretic damping have also been incorporated in the finite element model. Various results have been obtained such as Campbell diagram, stability speed limit, damping ratio, and time responses for functionally graded shaft and also compared with conventional steel shaft. It has been found that the responses of the functionally graded spinning shaft are significantly influenced by material properties, radial thickness, power law gradient index, and internal (viscous and hysteretic) damping. The obtained results also show the advantages of functionally graded shaft over conventional steel shaft.

The free and forced response of spinning, viscoelastic, Rayleigh shafts is studied. Viscoelasticity is included using the three parameter solid model. The closed form polynomial frequency equation and integral expressions for the response to a general forcing function are derived. A convenient decay parameter is described. Results are given for natural frequencies and decay rates as functions of shaft rotation speed, stiffness, and viscosity. It is found that shaft materials are possible which have desirable damping and natural frequency characteristics. A parameter case is discussed in which natural frequency and damping simultaneous increase, while stiffness is held constant. Also, the special case of forced response to a step load is derived and used to illustrate the combined effects of viscoelasticity and gyroscopic forces.

Transient phenomena are generally inherent in the operation of compressor stations: These are either fast or slow transients. A model describing the governing equation for the gas dynamics, control system, compressor and turbine shaft inertias has been developed. The effect of these inertias is manifested by an example of a compressor station operating near the surge control line. Another example deals with a station that has a cooler placed in the recycle path. This alters the rate at which the compressor shaft decelerates upon shutdown and may cause backward spinning depending on the relative magnitude of the shaft inertia with respect to the cooler volume. Backward spinning of compressor shaft has detrimental effects on dry seals and is undesirable. It was found that by keeping the recycle valve closed upon shutdown, the rate of shaft deceleration will be reduced.

This study aims to determine the yarn spinning time, spinning equipment manufacturing costs, and haspel shaft spinning. Basic design is done by data collection, direct visits to the silk farmers' groups, tool design, tool manufacturing, performance testing tools, analysis, calculating costs and tool manufacturing. In accordance with the testing of the spinning machine, the total working time is 8 hours / day for 3.36 kg of silk yarn, the spinning equipment manufacturing cost is Rp. 5,102,534.71. Whereas BEP is achieved when the sale of spinning machines is at least 1 unit / month or when income is Rp. 5,621,064.

The dynamic behavior of a simply-supported spinning Timoshenko shaft with coupled bending and torsion is analyzed. This is accomplished by transforming the set of nonlinear partial differential equations of motion into a set of linear ordinary differential equations. This set of ordinary differential equations is a time-varying system and the solution is obtained analytically in terms of Chebyshev series. A beating phenomoenon is observed from the numerical simulations, which is not observed for shaft systems where only bending vibration is considered.

The problem faced by the Slap Strap Making Business Group is that the process of making slap ropes is still manual using a hand drill. This business group experienced many problems when using manual methods, such as the results of the twisting of the slapping rope were not uniform and many were loose. The second obstacle faced is that manual labor requires a lot of manpower for the slap rope spinning process. The last obstacle faced is when using a spinning machine there is a concern that the electricity supply will not be able to meet because the electricity supply in the area around the coast still uses 450 watts of electricity. So that if you use a spinning machine, it is hoped that the machine can be energy efficient and easy to use. The right solution is offered to solve the problem of the need for a spinning machine that is energy efficient and easy to use, namely the manufacture of a slap rope spinning machine with a chain shaft system. The machine includes various components, among others; frames, shafts, bearings, gears, dimmers, belts and pulleys. The propulsion system uses an electric motor. By using the slap rope spinning machine, it is be able to increase the efficiency and effectiveness of the slap rope spinning process.

The paper summarizes a complete analysis about vibrational characteristics of a spinning simply supported cracked shaft with fluid medium at finite region. The damping effect occurs due to external fluid is integrated in the existing analysis, with the help of navier - stokes equation. The simply supported cracked shaft is analyzed by the influence coefficient strain energy method. Here we have changing the parameter of shaft i.e. damping viscosity of fluid and the length of the shaft which accountable for the alteration of the amplitude of vibration.

This paper presents a spectral element model for the spinning uniform shaft represented by the Timoshenko beam model. The bearing-supports are represented by equivalent springs. The variational approach is used to formulate the spectral element model from the frequency-dependent shape functions derived from exact wave solutions to the governing differential equations.

This PhD thesis presents structural investigations of amorphous inorganic materials: oxide and oxynitride glasses and mesoporous bioactive glasses (MBGs), by solid-state Nuclear Magnetic Resonance (NMR). Lanthanum oxide and oxynitride [La-Si-(Al)-O-(N)] glasses have a large number of potential applications due to their physical properties. In our work we have studied, compared to previous investigations, significantly expanded ranges of glass compositions (for oxynitride glasses, including samples of very high nitrogen content, up to 53 % out of the anions). We have estimated local environments of 29Si and 27Al structural units (their coordination, polymerization degree and number of N incorporated into tetrahedral units) in the materials. We have suggested a random Al/Si distribution along with almost uniform non-bridging oxygen atoms distribution in aluminosilicate glasses. Silicon nitride was used as precursor in the oxynitride glass synthesis. We studied both α- and β-modifications of silicon nitride, 15N-enriched, as well as fully (29Si, 15N)-enriched samples. We have shown that the linewidths of 15N NMR spectra are dominated by J(29Si-15N) coupling in 29Si315N4 sample. Mesoporous bioactive glasses in the CaO-SiO2-P2O5 system show superior bioactivity (the ability to form a hydroxycarbonate apatite layer on the glass surface when exposed to body fluids) compared to conventional bioactive glasses due to their large surface area and uniform pore-size distribution. Previous studies suggested a homogeneous cation distribution over the MBG samples on a 10−20 nm length-scale. From our results, on the other hand, we may conclude that Si and P is not intimately mixed. We propose a structural model, in which the pore walls of MBGs are composed of a silica network, and a phosphate phase is present as nanometer-sized clusters that are dispersed on the pore wall.

博士
國立中興大學
機械工程學系
92
A finite element model for analyzing the vibration characteristics of composite shaft-disk-blade systems is presented here. The system consists of a composite blade attached to the rim of a rigid disk and a composite shaft to which the disk is fixed. This model is an extension of the composite blade and composite shaft models developed earlier by Chang et. al. by further taking also the coupling kinetic energy of the shaft and the blade into account. The extended Hamilton’s principle in conjunction with the finite element method is employed in deriving the equations of motion of system. The dynamic characteristics such as natural frequencies, whirling speeds and mode shapes of the composite shaft-disk-blade system are studied for various material and geometry properties of the blade and shaft, as well as for various rotating speeds. The numerical results indicate that the existence of the coupling flexible motion between blade and shaft could have significant influences on the dynamic characteristics of the system. For the purpose of verification, the results obtained using the current finite element model are compared with those obtained using the available commercial software for the case of a free non-rotating shaft-disk-blade system made of an isotropic material. The dynamic behaviors of the rotating composite shafts containing randomly oriented reinforcements are furthering investigated in this study. Incorporating the Mori-Tanaka mean-field theory to account for interaction at finite concentrations of reinforcements with the equivalent inclusion method, the effective elastic moduli are expressed as a function of phase properties, volume fraction, orientation angles, and reinforcements’ shape. Based on shaft’s model and taking these effective elastic moduli into account, the natural frequencies of the stationary shafts, and the whirling speeds as well as the critical speeds of the rotating shafts are presented.

The computational analysis of an eccentric rotor is based on the bondgraph approach where the eccentricity of the rotor is analysed using bondgraph. This approach is used in this experiment to justify the displacements in shaft rotation which is occurring due to eccentricity introduced in the shaft. The computational analysis is necessary because by getting these results, a graph can be plotted which will give an accurate result of the bondgraph approach and it can be seen that by how much the displacement is occurring when the eccentricity is increased. The modelling technique used in this approach introduces two shafts connected through a hub and is provided rotor excitation by connecting it through an external source that rotates it at different angular velocities. The shafts are connected in such a manner that it has displacements in radial axis and the displacement is noted. The bond graph modelling of shaft and spinning hub is done using symbol sonata software bond pad. Simulation of this model has been carried out on Symbols sonata software which uses the fourth order Runge-Kutta method. The variation in the position of centre mass of rotor with change in various parameters such as speed, clearance is observed. The data obtained is used to get plots.

碩士
國立中興大學
機械工程學系所
95
In this study, a spur gear coupled theory combined with a spinning composite flexible shaft theory, is used to develop a double spinning composite shafts model that are containing coupled by spur gears. The gears are assumed rigid, but at the contact gear teeth, a spring and viscose dashpot are used to simulate the effect due to the deformation of the teeth resulting from large contact forces. For the gears, firstly, the displacement and velocity vectors of the contact location are used to find the excitation forces that come from eccentricity and the static transmission error, and the coupled stiffness and damping matrices. Assembling the coupled stiffness and damping matrices in those of the composite shaft system, the governing equations of the whole system are derived. The governing equations are used to study the isotropic shafts and made of composite materials. The natural frequencies and vibration mode shapes are analyzed. Campbell diagrams are plotted. And then indicate that mode shapes may change as the spinning speed varies. Finally, the dynamic responses of the systems are analyzed using the mode summation method.

碩士
國立中興大學
機械工程學系所
98
The objective of this thesis is to study the dynamic responses of the flexible spinning-shaft system including the rigid-body motion effect. The spinning-shaft system being considered include the rigid disk, the flexible shaft, and bearing supports which are modeled as springs and viscous dampers. To derive, the equations of motion of the spinning-shaft system. First, the kinetic energy and the strain energy of the spinning shaft, the kinetic energy of the rigid disk, and the work done by support forces of the bearings and centrifugal force of the disk are found. Then by employing the Hamilton’s principle together with the finite element method, the equations of motion of the spinning-shaft system including both the rigid-body motion and flexible deformation effects of the shaft are obtained. In the study of dynamic responses, in order to simplify the analysis, the influence of the flexible deformation of the shaft on the rigid-body motion of system is neglected. The equations of motion then can be divided into two groups corresponding to that of rigid-body motion and that of flexible motion affected by the rigid-body motion. The nonlinear equations for rigid-body motion is further simplified to linear ones for comparison. In the numerical analysis, a higher-order Runge-Kutta method is used to solve the equations of motion describing the rigid-body motion of the system. With above obtained results equations of flexible motion affected by rigid-body motion are then analyzed by the Newmark’s method. The influences of the parameters such as rotational viscous damping coefficient, the locations of bearings and the disk, and the motor’s acceleration on the dynamic responses are investigated. Comparisons are also made with those of the spinning shaft system without considering the rigid-body motion effect.

Thesis (Ph. D.)--University of Illinois at Urbana-Champaign, 2008.
Source: Dissertation Abstracts International, Volume: 69-05, Section: B, page: 3023. Adviser: Chad M. Rienstra. Includes bibliographical references (leaves 222-233). Available on microfilm from Pro Quest Information and Learning.

Nationalism: Past as Prologue began as a single volume being compiled by Ad Akande, a scholar from South Africa, who proposed it to me as co-author about two years ago. The original idea was to examine how the damaging roots of nationalism have been corroding political systems around the world, and creating dangerous obstacles for necessary international cooperation. Since I (Bruce E. Johansen) has written profusely about climate change (global warming, a.k.a. infrared forcing), I suggested a concerted effort in that direction. This is a worldwide existential threat that affects every living thing on Earth. It often compounds upon itself, so delays in reducing emissions of fossil fuels are shortening the amount of time remaining to eliminate the use of fossil fuels to preserve a livable planet. Nationalism often impedes solutions to this problem (among many others), as nations place their singular needs above the common good. Our initial proposal got around, and abstracts on many subjects arrived. Within a few weeks, we had enough good material for a 100,000-word book. The book then fattened to two moderate volumes and then to four two very hefty tomes. We tried several different titles as good submissions swelled. We also discovered that our best contributors were experts in their fields, which ranged the world. We settled on three stand-alone books:” 1/ nationalism and racial justice. Our first volume grew as the growth of Black Lives Matter following the brutal killing of George Floyd ignited protests over police brutality and other issues during 2020, following the police assassination of Floyd in Minneapolis. It is estimated that more people took part in protests of police brutality during the summer of 2020 than any other series of marches in United States history. This includes upheavals during the 1960s over racial issues and against the war in Southeast Asia (notably Vietnam). We choose a volume on racism because it is one of nationalism’s main motive forces. This volume provides a worldwide array of work on nationalism’s growth in various countries, usually by authors residing in them, or in the United States with ethnic ties to the nation being examined, often recent immigrants to the United States from them. Our roster of contributors comprises a small United Nations of insightful, well-written research and commentary from Indonesia, New Zealand, Australia, China, India, South Africa, France, Portugal, Estonia, Hungary, Russia, Poland, Kazakhstan, Georgia, and the United States. Volume 2 (this one) describes and analyzes nationalism, by country, around the world, except for the United States; and 3/material directly related to President Donald Trump, and the United States. The first volume is under consideration at the Texas A & M University Press. The other two are under contract to Nova Science Publishers (which includes social sciences). These three volumes may be used individually or as a set. Environmental material is taken up in appropriate places in each of the three books. * * * * * What became the United States of America has been strongly nationalist since the English of present-day Massachusetts and Jamestown first hit North America’s eastern shores. The country propelled itself across North America with the self-serving ideology of “manifest destiny” for four centuries before Donald Trump came along. Anyone who believes that a Trumpian affection for deportation of “illegals” is a new thing ought to take a look at immigration and deportation statistics in Adam Goodman’s The Deportation Machine: America’s Long History of Deporting Immigrants (Princeton University Press, 2020). Between 1920 and 2018, the United States deported 56.3 million people, compared with 51.7 million who were granted legal immigration status during the same dates. Nearly nine of ten deportees were Mexican (Nolan, 2020, 83). This kind of nationalism, has become an assassin of democracy as well as an impediment to solving global problems. Paul Krugman wrote in the New York Times (2019:A-25): that “In their 2018 book, How Democracies Die, the political scientists Steven Levitsky and Daniel Ziblatt documented how this process has played out in many countries, from Vladimir Putin’s Russia, to Recep Erdogan’s Turkey, to Viktor Orban’s Hungary. Add to these India’s Narendra Modi, China’s Xi Jinping, and the United States’ Donald Trump, among others. Bit by bit, the guardrails of democracy have been torn down, as institutions meant to serve the public became tools of ruling parties and self-serving ideologies, weaponized to punish and intimidate opposition parties’ opponents. On paper, these countries are still democracies; in practice, they have become one-party regimes….And it’s happening here [the United States] as we speak. If you are not worried about the future of American democracy, you aren’t paying attention” (Krugmam, 2019, A-25). We are reminded continuously that the late Carl Sagan, one of our most insightful scientific public intellectuals, had an interesting theory about highly developed civilizations. Given the number of stars and planets that must exist in the vast reaches of the universe, he said, there must be other highly developed and organized forms of life. Distance may keep us from making physical contact, but Sagan said that another reason we may never be on speaking terms with another intelligent race is (judging from our own example) could be their penchant for destroying themselves in relatively short order after reaching technological complexity. This book’s chapters, introduction, and conclusion examine the worldwide rise of partisan nationalism and the damage it has wrought on the worldwide pursuit of solutions for issues requiring worldwide scope, such scientific co-operation public health and others, mixing analysis of both. We use both historical description and analysis. This analysis concludes with a description of why we must avoid the isolating nature of nationalism that isolates people and encourages separation if we are to deal with issues of world-wide concern, and to maintain a sustainable, survivable Earth, placing the dominant political movement of our time against the Earth’s existential crises. Our contributors, all experts in their fields, each have assumed responsibility for a country, or two if they are related. This work entwines themes of worldwide concern with the political growth of nationalism because leaders with such a worldview are disinclined to co-operate internationally at a time when nations must find ways to solve common problems, such as the climate crisis. Inability to cooperate at this stage may doom everyone, eventually, to an overheated, stormy future plagued by droughts and deluges portending shortages of food and other essential commodities, meanwhile destroying large coastal urban areas because of rising sea levels. Future historians may look back at our time and wonder why as well as how our world succumbed to isolating nationalism at a time when time was so short for cooperative intervention which is crucial for survival of a sustainable earth. Pride in language and culture is salubrious to individuals’ sense of history and identity. Excess nationalism that prevents international co-operation on harmful worldwide maladies is quite another. As Pope Francis has pointed out: For all of our connectivity due to expansion of social media, ability to communicate can breed contempt as well as mutual trust. “For all our hyper-connectivity,” said Francis, “We witnessed a fragmentation that made it more difficult to resolve problems that affect us all” (Horowitz, 2020, A-12). The pope’s encyclical, titled “Brothers All,” also said: “The forces of myopic, extremist, resentful, and aggressive nationalism are on the rise.” The pope’s document also advocates support for migrants, as well as resistance to nationalist and tribal populism. Francis broadened his critique to the role of market capitalism, as well as nationalism has failed the peoples of the world when they need co-operation and solidarity in the face of the world-wide corona virus pandemic. Humankind needs to unite into “a new sense of the human family [Fratelli Tutti, “Brothers All”], that rejects war at all costs” (Pope, 2020, 6-A). Our journey takes us first to Russia, with the able eye and honed expertise of Richard D. Anderson, Jr. who teaches as UCLA and publishes on the subject of his chapter: “Putin, Russian identity, and Russia’s conduct at home and abroad.” Readers should find Dr. Anderson’s analysis fascinating because Vladimir Putin, the singular leader of Russian foreign and domestic policy these days (and perhaps for the rest of his life, given how malleable Russia’s Constitution has become) may be a short man physically, but has high ambitions. One of these involves restoring the old Russian (and Soviet) empire, which would involve re-subjugating a number of nations that broke off as the old order dissolved about 30 years ago. President (shall we say czar?) Putin also has international ambitions, notably by destabilizing the United States, where election meddling has become a specialty. The sight of Putin and U.S. president Donald Trump, two very rich men (Putin $70-$200 billion; Trump $2.5 billion), nuzzling in friendship would probably set Thomas Jefferson and Vladimir Lenin spinning in their graves. The road of history can take some unanticipated twists and turns. Consider Poland, from which we have an expert native analysis in chapter 2, Bartosz Hlebowicz, who is a Polish anthropologist and journalist. His piece is titled “Lawless and Unjust: How to Quickly Make Your Own Country a Puppet State Run by a Group of Hoodlums – the Hopeless Case of Poland (2015–2020).” When I visited Poland to teach and lecture twice between 2006 and 2008, most people seemed to be walking on air induced by freedom to conduct their own affairs to an unusual degree for a state usually squeezed between nationalists in Germany and Russia. What did the Poles then do in a couple of decades? Read Hlebowicz’ chapter and decide. It certainly isn’t soft-bellied liberalism. In Chapter 3, with Bruce E. Johansen, we visit China’s western provinces, the lands of Tibet as well as the Uighurs and other Muslims in the Xinjiang region, who would most assuredly resent being characterized as being possessed by the Chinese of the Han to the east. As a student of Native American history, I had never before thought of the Tibetans and Uighurs as Native peoples struggling against the Independence-minded peoples of a land that is called an adjunct of China on most of our maps. The random act of sitting next to a young woman on an Air India flight out of Hyderabad, bound for New Delhi taught me that the Tibetans had something to share with the Lakota, the Iroquois, and hundreds of other Native American states and nations in North America. Active resistance to Chinese rule lasted into the mid-nineteenth century, and continues today in a subversive manner, even in song, as I learned in 2018 when I acted as a foreign adjudicator on a Ph.D. dissertation by a Tibetan student at the University of Madras (in what is now in a city called Chennai), in southwestern India on resistance in song during Tibet’s recent history. Tibet is one of very few places on Earth where a young dissident can get shot to death for singing a song that troubles China’s Quest for Lebensraum. The situation in Xinjiang region, where close to a million Muslims have been interned in “reeducation” camps surrounded with brick walls and barbed wire. They sing, too. Come with us and hear the music. Back to Europe now, in Chapter 4, to Portugal and Spain, we find a break in the general pattern of nationalism. Portugal has been more progressive governmentally than most. Spain varies from a liberal majority to military coups, a pattern which has been exported to Latin America. A situation such as this can make use of the term “populism” problematic, because general usage in our time usually ties the word into a right-wing connotative straightjacket. “Populism” can be used to describe progressive (left-wing) insurgencies as well. José Pinto, who is native to Portugal and also researches and writes in Spanish as well as English, in “Populism in Portugal and Spain: a Real Neighbourhood?” provides insight into these historical paradoxes. Hungary shares some historical inclinations with Poland (above). Both emerged from Soviet dominance in an air of developing freedom and multicultural diversity after the Berlin Wall fell and the Soviet Union collapsed. Then, gradually at first, right wing-forces began to tighten up, stripping structures supporting popular freedom, from the courts, mass media, and other institutions. In Chapter 5, Bernard Tamas, in “From Youth Movement to Right-Liberal Wing Authoritarianism: The Rise of Fidesz and the Decline of Hungarian Democracy” puts the renewed growth of political and social repression into a context of worldwide nationalism. Tamas, an associate professor of political science at Valdosta State University, has been a postdoctoral fellow at Harvard University and a Fulbright scholar at the Central European University in Budapest, Hungary. His books include From Dissident to Party Politics: The Struggle for Democracy in Post-Communist Hungary (2007). Bear in mind that not everyone shares Orbán’s vision of what will make this nation great, again. On graffiti-covered walls in Budapest, Runes (traditional Hungarian script) has been found that read “Orbán is a motherfucker” (Mikanowski, 2019, 58). Also in Europe, in Chapter 6, Professor Ronan Le Coadic, of the University of Rennes, Rennes, France, in “Is There a Revival of French Nationalism?” Stating this title in the form of a question is quite appropriate because France’s nationalistic shift has built and ebbed several times during the last few decades. For a time after 2000, it came close to assuming the role of a substantial minority, only to ebb after that. In 2017, the candidate of the National Front reached the second round of the French presidential election. This was the second time this nationalist party reached the second round of the presidential election in the history of the Fifth Republic. In 2002, however, Jean-Marie Le Pen had only obtained 17.79% of the votes, while fifteen years later his daughter, Marine Le Pen, almost doubled her father's record, reaching 33.90% of the votes cast. Moreover, in the 2019 European elections, re-named Rassemblement National obtained the largest number of votes of all French political formations and can therefore boast of being "the leading party in France.” The brutality of oppressive nationalism may be expressed in personal relationships, such as child abuse. While Indonesia and Aotearoa [the Maoris’ name for New Zealand] hold very different ranks in the United Nations Human Development Programme assessments, where Indonesia is classified as a medium development country and Aotearoa New Zealand as a very high development country. In Chapter 7, “Domestic Violence Against Women in Indonesia and Aotearoa New Zealand: Making Sense of Differences and Similarities” co-authors, in Chapter 8, Mandy Morgan and Dr. Elli N. Hayati, from New Zealand and Indonesia respectively, found that despite their socio-economic differences, one in three women in each country experience physical or sexual intimate partner violence over their lifetime. In this chapter ther authors aim to deepen understandings of domestic violence through discussion of the socio-economic and demographic characteristics of theit countries to address domestic violence alongside studies of women’s attitudes to gender norms and experiences of intimate partner violence. One of the most surprising and upsetting scholarly journeys that a North American student may take involves Adolf Hitler’s comments on oppression of American Indians and Blacks as he imagined the construction of the Nazi state, a genesis of nationalism that is all but unknown in the United States of America, traced in this volume (Chapter 8) by co-editor Johansen. Beginning in Mein Kampf, during the 1920s, Hitler explicitly used the westward expansion of the United States across North America as a model and justification for Nazi conquest and anticipated colonization by Germans of what the Nazis called the “wild East” – the Slavic nations of Poland, the Baltic states, Ukraine, and Russia, most of which were under control of the Soviet Union. The Volga River (in Russia) was styled by Hitler as the Germans’ Mississippi, and covered wagons were readied for the German “manifest destiny” of imprisoning, eradicating, and replacing peoples the Nazis deemed inferior, all with direct references to events in North America during the previous century. At the same time, with no sense of contradiction, the Nazis partook of a long-standing German romanticism of Native Americans. One of Goebbels’ less propitious schemes was to confer honorary Aryan status on Native American tribes, in the hope that they would rise up against their oppressors. U.S. racial attitudes were “evidence [to the Nazis] that America was evolving in the right direction, despite its specious rhetoric about equality.” Ming Xie, originally from Beijing, in the People’s Republic of China, in Chapter 9, “News Coverage and Public Perceptions of the Social Credit System in China,” writes that The State Council of China in 2014 announced “that a nationwide social credit system would be established” in China. “Under this system, individuals, private companies, social organizations, and governmental agencies are assigned a score which will be calculated based on their trustworthiness and daily actions such as transaction history, professional conduct, obedience to law, corruption, tax evasion, and academic plagiarism.” The “nationalism” in this case is that of the state over the individual. China has 1.4 billion people; this system takes their measure for the purpose of state control. Once fully operational, control will be more subtle. People who are subject to it, through modern technology (most often smart phones) will prompt many people to self-censor. Orwell, modernized, might write: “Your smart phone is watching you.” Ming Xie holds two Ph.Ds, one in Public Administration from University of Nebraska at Omaha and another in Cultural Anthropology from the Chinese Academy of Social Sciences, Beijing, where she also worked for more than 10 years at a national think tank in the same institution. While there she summarized news from non-Chinese sources for senior members of the Chinese Communist Party. Ming is presently an assistant professor at the Department of Political Science and Criminal Justice, West Texas A&M University. In Chapter 10, analyzing native peoples and nationhood, Barbara Alice Mann, Professor of Honours at the University of Toledo, in “Divide, et Impera: The Self-Genocide Game” details ways in which European-American invaders deprive the conquered of their sense of nationhood as part of a subjugation system that amounts to genocide, rubbing out their languages and cultures -- and ultimately forcing the native peoples to assimilate on their own, for survival in a culture that is foreign to them. Mann is one of Native American Studies’ most acute critics of conquests’ contradictions, and an author who retrieves Native history with a powerful sense of voice and purpose, having authored roughly a dozen books and numerous book chapters, among many other works, who has traveled around the world lecturing and publishing on many subjects. Nalanda Roy and S. Mae Pedron in Chapter 11, “Understanding the Face of Humanity: The Rohingya Genocide.” describe one of the largest forced migrations in the history of the human race, the removal of 700,000 to 800,000 Muslims from Buddhist Myanmar to Bangladesh, which itself is already one of the most crowded and impoverished nations on Earth. With about 150 million people packed into an area the size of Nebraska and Iowa (population less than a tenth that of Bangladesh, a country that is losing land steadily to rising sea levels and erosion of the Ganges river delta. The Rohingyas’ refugee camp has been squeezed onto a gigantic, eroding, muddy slope that contains nearly no vegetation. However, Bangladesh is majority Muslim, so while the Rohingya may starve, they won’t be shot to death by marauding armies. Both authors of this exquisite (and excruciating) account teach at Georgia Southern University in Savannah, Georgia, Roy as an associate professor of International Studies and Asian politics, and Pedron as a graduate student; Roy originally hails from very eastern India, close to both Myanmar and Bangladesh, so he has special insight into the context of one of the most brutal genocides of our time, or any other. This is our case describing the problems that nationalism has and will pose for the sustainability of the Earth as our little blue-and-green orb becomes more crowded over time. The old ways, in which national arguments often end in devastating wars, are obsolete, given that the Earth and all the people, plants, and other animals that it sustains are faced with the existential threat of a climate crisis that within two centuries, more or less, will flood large parts of coastal cities, and endanger many species of plants and animals. To survive, we must listen to the Earth, and observe her travails, because they are increasingly our own.

As we continue our exploration of who rules the earth, we find that the economy, once you look inside it, relies on a vast system of rules and regulations, its cogs and wheels spinning day and night to enable the countless transactions that make up a modern economy. The relation between markets and rules is a fascinating one, far more complex than is suggested by the usual debates over government regulation versus free enterprise. Markets rely on rules. But increasingly, the reverse is also true: Some of our most innovative environmental policies and regulations have embedded within them market incentives designed to promote pro-environment behavior. To appreciate the stakes, let’s begin by considering what is arguably the greatest environmental tragedy—and biggest environmental success story—of all time. The removal of tetraethyl lead from gasoline has had a profound impact on human health and well-being worldwide. The change began in the United States in the late 1970s, soon spread to Europe, and over the next two decades diffused throughout the entire world. This shift was prompted by an innovative set of rules that actually assigned property rights to poison—and in the process created incentives for widespread changes in corporate behavior. Under the Clean Air Act of 1970, the US Environmental Protection Agency had the legal authority to regulate tetraethyl lead, which had been added to gasoline since the 1920s to boost engine performance. The original decision to add “ethyl” to the chemical mixture sloshing around in our gas tanks took place despite dire warnings from health experts. Foremost among these was Alice Hamilton, Harvard’s first female professor and the country’s leading expert on the health impacts of lead, which she knew intimately from her studies of worker exposure in the largely unregulated “dangerous trades” of the time. In 1925, the US Surgeon General convened a special meeting to decide whether ethyl production could proceed despite the known health risks. Hamilton argued that it would be reckless to deliberately disperse throughout the air a substance whose toxic effects (notably damage to the human nervous system) were well known for centuries.

Transient phenomena are generally inherent in the operation of compressor stations: these are either fast or slow transients. A model describing the governing equation for the gas dynamics, control system, compressor and turbine shafts inertias has been developed. The effect of these inertias is manifested by an example of a compressor station operating near the surge control line. Another example deals with a station that has a cooler placed in the recycle path. This alters the rate at which the compressor shaft decelerates upon shutdown and may cause backward spinning depending on the relative magnitude of the shaft inertia with respect to the cooler volume. Backward spinning of compressor shaft has detrimental effects on dry seals and is undesirable. It was found that by keeping the recycle valve closed upon shutdown, the rate of shaft deceleration will be reduced.

Abstract Free lateral vibration of stepped shafts is investigated in this paper using the Timoshenko beam theory and the finite element method. Beam finite elements having two nodes and 16 degrees of freedom were employed to model flexural vibration of a stepped shaft for a total four field variables — two lateral displacements and two bending angles. Within each uniform segment, the stepped shaft is modeled as a substructure for which a system of equations of motion may be easily formulated using the Galerkin method. The global equations of motion for the entire stepped shaft are subsequently formulated by enforcing the displacement continuity and force equilibrium conditions across the interfaces between two adjacent substructures. The second order governing differential equations for a non self-adjoint dynamic system are then reduced to the equivalent first order differential equations for which eigenvalue problem is formulated and solved using the Matlab® program. Values of natural frequencies are in excellent agreement with those available in the literature. Effects of rotational springs attached to the end of a stepped shaft, used to simulate the non-classical boundary constraints of chuck on a work piece in a typical turning process, are also investigated. The bi-orthogonal conditions for modal vectors, which are useful in chatter analysis during turning processes, are given in this paper.

Abstract Within this paper problems related with the vibration and stability control of circular flexible shafts spinning about their rotational axis are addressed. Due to the occurrence, as a result of the spinning speed, of gyroscopic forces in the system, the rotating shaft can experience, in some conditions, instabilities of the same nature as any nonconservative system, namely divergence and flutter instabilities. Whereas the former instability is of a static character, the latter one is of dynamic character and the results of its occurrence are catastrophic. By including collocated sending and actuating capabilities via integration in the system of piezoelectric devices and of a feedback control law, it is shown that a dramatic enhancement of both the free dynamic response and of the stability behavior from both the divergence and flutter points of view can be achieved. This implies that via the implementation of this technology an increase of the spinning speed can be achieved without the occurrence of these instabilities. Numerical simulations documenting these findings are provided and pertinent conclusions are outlined. It is also worthy to mention that the shaft is modeled as a thin-walled cylinder made of an anisotropic material and incorporating a number of non-classical features.

Abstract The dynamic behavior of a simply-supported spinning Timoshenko shaft with coupled bending and torsion is analyzed. This is accomplished by transforming the set of nonlinear partial differential equations of motion into a set of linear ordinary differential equations. This set of ordinary differential equations is a time-varying system and the solution is obtained analytically in terms of Chebyshev series. The analytical method is a viable alternative to numerical methods and can provide the full range of the required solutions. A beating phenomenon is observed from the numerical simulations. This phenomenon occurs when the system has two natural frequencies close to each other. It is also shown that the period of torsional vibrations is much shorter than the period of oscillations in transverse deflections and in bending angles.

Abstract The vibration of a spinning annular disk with coupled translational and rotational rigid body motion is analyzed. The spinning disk, with one linear spring as transverse load, is free to translate and rotate relative to the shaft axis. The governing equation includes the rigid body translation, rigid body rotation, and flexible disk vibration. Coupling effect between rigid body motion and each annular disk vibration modes is identified. Because of the coupling effects, stable operation of the spinning disk beyond divergence (critical speed) is achieved, the disk loses its stability to flutter. This stability prediction is different from that of a spinning disk without rigid body motion where the disk is unstable at and right after divergence.

Abstract The critical speeds of a spinning Timoshenko shaft with an intermediate attached disk subjected to a longitudinal force are analytically solved. The expressions of whirl speed equations for hinged-hinged, hinged-clamped, clamped-hinged, and clamped-clamped rotors are given respectively. The critical speeds of each shaft-disk system are sought from its corresponding whirl speed equation by using simple numerical techniques. The effects of the disk location and the longitudinal force on the critical speeds of the shaft-disk systems are investigated. Numerical results reveal that if the disk locates in the left portion of the shaft, both the primary forward and backward critical speeds for the rotor subjected to a follower force are larger than those subjected to an axial force with the same magnitude. The results are contrary while the disk locates in the right portion of the shaft.

Bulkhead seals are critical safety components which stop progressive flooding between watertight compartments at the location of the shaft penetration through the bulkhead. Most bulkhead seal technology is based on a contacting approach where sealing materials are always in contact with the spinning shaft. Radial and axial shaft motion, vibration, shaft mis-alignment, bulkhead mis-alignment, seal orientation and air pressure differentials can cause these contacting bulkhead seals to pre-maturely wear or fail. This wear then leads to substantial maintenance costs if the seals are properly inspected and maintained or can lead to catastrophic failure should the seals not be properly maintained. This paper will present a new non-contacting and non-rotating bulkhead seal design that only activates in the presence of water.

In this paper, the tapered roller bearing supported on the output shaft of the dual clutch transmission was studied. During the operating process of the DCT (Dual Clutch Transmission) gearbox, the heat generation of the bearing is very large due to the large operating load and high operating speed, which will easily result in bearing failure, such as pitting and abrasion, so it is necessary to investigate the lubrication performances and thermal characteristics of the tapered roller bearing. The simulation models considering or not considering the roller’s spinning (the rollers rotating on their own axles) were established based on Ansys Fluent software. The influences of the roller’s spinning on the lubrication performances of the bearing were analyzed. Furthermore, the transit heat transfer properties of the bearing were simulated and analyzed. The roller’s spinning and transit heat boundary specification were realized by using UDF (user-defined functions). At the same time, the lubrication performances and heat transfer properties of the bearing with different operating conditions are presented and analyzed.