Academic literature on the topic 'Threads'

Several techniques are at disposal for production or repair of internal threads. The repair of threads by means of flexible thread inserts and the repair of threads by means of sold thin walled thread inserts belong to the most important ways. The properties of threads repaired using flexible and solid thin-walled thread inserts were experimentally verified and compared. Laboratory comparison of loading capacity of the threads according to observance of specified technological procedures was carried out. Durability and reliability of the repaired threads were verified in operation, while the threads endured long-time variable mechanical and temperature load.

Threaded connections are commonly employed in axial load-bearing equipment and pressure vessel components. There are a number of parameters that affect the load distribution between the threads and the stress concentration at the thread roots. These include the thread form, the thickness of walls supporting the threads, the pitch of threads, number of threads engaged, and the boundary conditions. In this paper, the influence of these parameters on the load distribution between threads is reported. Load distribution analyses in threaded connections is performed by analytical and by finite element methods. Square and buttress-type threads have been considered. Three-dimensional nonlinear finite element analyses on threaded connections have been performed using MSC/NASTRAN finite element code. The effect of clearance between the nonmating faces of threads as well as the presence of a flexible media between the mating faces of threads are investigated.

Present classification systems for thought disorder lack consistency and require one to remember long-winded definitions limiting their use to research settings. as an extension of recent work in this area (World Congress, 2008), we classify the characteristic thought disorder patterns seen in schizophrenia according to the location of the lesion in notional "threads" of mental computational processes that string speech together. These threads must take both semantics and syntax into consideration in performing their function. When we speak - just as when we write - there is a natural hierarchy topic thread (the topic of the ‘essay’) and multiples of paragraph threads, sentence threads, clause threads, word threads and phoneme threads. Intuitively, we grade the severity of thought disorder depending upon whether a particular thread gets stuck (S), reconnects abnormally (R) or is absent altogether:I.paragraph thread R: Disjointed sentences S: Circumstantiality;II.topic threadR: Tangentiality S: Preoccupatory thinking;III.sentence threads R: Knight's move thinking S: Clause perseveration;IV.clause threads R: Word salad S: Word perseveration, fusion;V.word threads R: Incoherent sounds/ neologisms/ paraphasias S: Phoneme/syllable perseveration;VI.phoneme threads - Failure of production: Mutism.Of course, one must record all the lesions that are present at any given time. This scale incorporates a intuitive progression from mild to severe thought disorder in Schizophrenia. Using the STDS would allow the straightforward ‘bedside’ quantification of the severity of thought disorder and enforce discipline into the thought assessment section of the Mental State Examination.

Premolded internal threads on composite tubes were developed. The composite tubes with threads on both ends were made using a mandrel with a male thread. The threads can be applied to struts with adjustable end fits and composite pressure vessels with threaded caps that enable disassembly for inspection and repair. Carbon fiber-reinforced plastic (CFRP) prepregs were laid up on a mandrel, wrapped with shrink tape, and cured in an oven. The threads were built-in, without using machine cutting, and the fibers on the thread were continuous through the thread and tubes for high strength. The thread was alternately rounded, convex, and concave in shape to enable CFRP prepregs to be laid up. Two types of specimen were made and tested. The layup sequence of specimen A was [0/h/90/h/0/h(1/2)]s, and that of specimen B was [0/h/90/h/90/h/0/h/90/h/90/h/90/h/90/h/0/h/90/90/0], where “h” denotes a helical layer along the concave part of the threads. The relation between load and strain is nonlinear because of the rounded shape of the threads; however, a simple and closed form analytical model was able to predict the strength of the threads and design of the threads. The model was compared with the experimental results. In addition, an application of threads for the pressure vessel of the hybrid rocket motor is also reported. The combustion test proceeded without failure. Visual inspection after the test indicated that the threads and tubes were not damaged, and thus, they can be applied to high-pressure and high-temperature rocket motors.

Threaded connections are used in a lot of mechanical and civil engineering applications and, nowadays, are perhaps the most developed and economical way to join two elements made of any kind of material. It is well known that when a bolt is screwed into a threaded hole, the first threads engaged bear more than half of the axial load induced by the make-up torque. This overload in correspondence with the first threads engaged, together with the steep stress gradient induced by the notch effect at the thread root, is the cause of dramatic fatigue failures. Moreover, it is on the first threads engaged, because of the presence of high contact loads on the flanks of the threads, that galling can arise and promote surface damage if the threaded connection has to be screwed and unscrewed many times. The object of this paper is to propose a numerical finite element procedure, confirmed by means of full-scale experimental tests, which makes it possible to quantify the effects induced by varying the taper of rotary shouldered connections (RSCs), in terms of stress state, loads carried by the threads and pressure on the thread flanks. RSCs are conical threaded connections used in the oil industry and the aim of the procedure is to provide the designer with a useful tool able to minimize the dangerous effects of galling and overload.

Threaded components play a crucial role in ensuring the safety and reliability of systems by joining components together. Proper selection of thread type and size, ensuring proper machining and storage of components, and addressing potential issues such as leakage, vibration, and misalignment all play a special role. It is known that there is a big difference in the nature of the destruction of metal and plastic threaded connections, in particular, when the nut is made of plastics, and the bolt is made of steel, or vice versa. In this regard, at present there is no consensus in assessing the strength of plastic threaded connections. On the one hand, it is recognized that, due to a more uniform distribution of the load, plastic threaded connections have a significant load capacity. Numerous examples of the use of plastic threaded connections in pressure pipelines, in large plastic parts subjected to dynamic loads, various loaded fasteners - all these examples confirm that plastic threaded connections can withstand very high loads. Production of a thread of plastic details is rather difficult, than on metals. It is connected with the physical-mechanical processes coming in the course of production of concrete thread details from plastic by method of pressing and casting under pressure. Also mechanics of formation of plastic threads on details of the oil-field equipment on the specific properties differ from the threads received by a machining method on metals. As thread surfaces on plastic details are formed in compression molds depending on materials and the modes: temperatures, pressure and time of production. These regime parameters and guided parameters play a part at a guaranty of physicalmechanical properties of details in the course of production. The use of plastic or polymer threads in the oil and gas industry is increasing due to their unique characteristics and advantages over traditional metal threads. Recently, 3D printing (additive manufacturing) has become more widely used for the preparation of plastic threads. The article will discuss the methods and characteristics of preparing plastic threaded components, as well as their advantages and certain incompatibilities. Keywords: threaded components, plastic threaded components, preparation methods, 3D and 4D printing.

The Langmuir-Blodgett (LB) method is a well-known deposition technique for the fabrication of ordered monolayer and multilayer thin films of nanomaterials onto different substrates that plays a critical role in the development of functional devices for various applications. This paper describes detailed studies about the best coating configuration for nanoparticles of a porous metal-organic framework (MOF) onto both insulating or conductive threads and nylon fiber. We design and fabricate customized polymethylmethacrylate sheets (PMMA) holders to deposit MOF layers onto the threads or fiber using the LB technique. Two different orientations, namely, horizontal and vertical, are used to deposit MIL-96(Al) monolayer films onto five different types of threads and nylon fiber. These studies show that LB film formation strongly depends on deposition orientation and the type of threads or fiber. Among all the samples tested, cotton thread and nylon fiber with vertical deposition show more homogenous monolayer coverage. In the case of conductive threads, the MOF particles tend to aggregate between the conductive thread’s fibers instead of forming a continuous monolayer coating. Our results show a significant contribution in terms of MOF monolayer deposition onto single fiber and threads that will contribute to the fabrication of single fiber or thread-based devices in the future.

The Langmuir-Blodgett (LB) method is a well-known deposition technique for the fabrication of ordered monolayer and multilayer thin films of nanomaterials onto different substrates that plays a critical role in the development of functional devices for various applications. This paper describes detailed studies about the best coating configuration for nanoparticles of a porous metal-organic framework (MOF) onto both insulating or conductive threads and nylon fiber. We design and fabricate customized polymethylmethacrylate sheets (PMMA) holders to deposit MOF layers onto the threads or fiber using the LB technique. Two different orientations, namely, horizontal and vertical, are used to deposit MIL-96(Al) monolayer films onto five different types of threads and nylon fiber. These studies show that LB film formation strongly depends on deposition orientation and the type of threads or fiber. Among all the samples tested, cotton thread and nylon fiber with vertical deposition show more homogenous monolayer coverage. In the case of conductive threads, the MOF particles tend to aggregate between the conductive thread’s fibers instead of forming a continuous monolayer coating. Our results show a significant contribution in terms of MOF monolayer deposition onto single fiber and threads that will contribute to the fabrication of single fiber or thread-based devices in the future.

The dental implants are used for replacement of missing teeth, and it’s have been widely used for restore the function, esthetic, speech, and patient confidence. It forms the contact between the implant and the bone. The implant threads are altered to improve the initial contact, primary stability, increase the surface area, and facilitate dissipation of loads at the implant and bone surface. Implant thread design is one of the key factors it determines the primary stability and stress distribution during osseointegration, the threaded implants are reduced both stress on bone and sliding distance between the implant and bone. The primary stability is play a important role in less bone quality, double and triple threaded implant increases the primary stability than single threaded implant, the implant threads distribute mechanical stress equally at bone implant interface, lead to stability of dental implants and less bone resorption and also higher thread profile improve the primary stability, the success or failure of implants depend on the thread designs and quality of bone.

Purpose This paper aims to develop a single regression model (instead of developing models separately for each thread type) to predict the sewing thread consumption for cotton and polyester staple spun threads. Design/methodology/approach A single regression model is developed for predicting sewing thread consumption for cotton and polyester threads. The polyester sewing threads have lower sewing thread consumption as compared to cotton threads because of their higher elongation behaviour. The model differentiates between the cotton and polyester sewing threads using their elongation values at peak levels of tensions experienced by the sewing threads during stitch tightening. By comparing the estimated thread consumption values with actual values, the effectiveness of model is evaluated with root mean square error and coefficient of determination (R2). Findings During the sewing process, by understanding the behaviour of different types of sewing threads, it is possible to develop a single regression model for all types of threads. Practical implications The sewing thread consumption can be easily calculated for cotton and polyester sewing threads using a single regression equation using the sewing assembly thickness, stitch density and elongation of thread at peak tension. The garment manufacturers need not depend on different charts for sewing thread consumption for stock management. Originality/value The sewing thread consumption is different for different types of threads, and garment manufacturers have to depend on different charts given by sewing thread manufacturers or use different equations for each type of threads. Using this single regression equation, sewing thread consumption for cotton and polyester sewing thread can be estimated accurately.

Common principles, or threads, are studied that are readily found in both spiritual traditions (including religion) and in the field of sustainability. Oneness, Living Simply, Purity, and Care and Heart are examined at length, while Awakening, Awe and Wonder, and Preservation of Life are covered briefly. Opposite principles—for example, Oneness versus Fracturedness, and Purity versus Pollution—are analyzed as well. Principles and their opposites are found to have both high and low modes. Each polarity has life-supporting and life-degrading forms.

Spiritual and religious traditions are grouped into five broad categories. While three of the categories consist of world religions (traditions of Indian origin, Abrahamic traditions, and East Asian traditions), also included are indigenous traditions, alchemy and Hermeticism, and modern spiritual teachings. Sustainability is organized into three categories: ecological science, activism, and sustainable business.

The common threads between sustainability and spirituality are most reliably found in the segments of world religions that tend toward mysticism, and within teachings that emphasize the cultivation of a greater capacity for just awareness, or presence itself, such as Eckhart Tolle’s works. Indigenous traditions shine as examples of societies that have embodied, and in some cases, continue to embody life-supporting principles far more explicitly and fully than cultures that have lost intimacy with their local ecosystems.

The conclusions drawn based on findings is that wisdom traditions corroborate the idea that the outer world is a reflection of the inner world, and that improving the state of the planet therefore requires personal transformation as a prerequisite to outer improvements. A higher order of intelligence, or nous, referenced in multiple mystical traditions, is indispensable to sustainability work. This and other spiritual principles directly inform sustainability efforts, but to be fully employed they require first-hand, personal experience of spiritual realities. Those who would work toward a genuinely sustainable society are urged to pursue mystical or presence-based spiritual training and experience as a matter of urgency, including direct interaction with nature to facilitate rebuilding intimacy with ecosystems, combined with deepening understanding of ecologically sophisticated indigenous lifeways.

Los temas de investigación sobre multithreading han ganado mucho interés en la arquitectura de computadores con la aparición de procesadores multihilo y multinucleo. Los procesadores SMT (Simultaneous Multithreading) son uno de estos nuevos paradigmas, combinando la capacidad de emisión de múltiples instrucciones de los procesadores superscalares con la habilidad de explotar el paralelismo a nivel de hilos (TLP). Así, la principal característica de los procesadores SMT es ejecutar varios hilos al mismo tiempo para incrementar la utilización de las etapas del procesador mediante la compartición de recursos.
Los recursos compartidos son el factor clave de los procesadores SMT, ya que esta característica conlleva tratar con importantes cuestiones pues los hilos también compiten por estos recursos en el núcleo del procesador. Si bien distintos grupos de aplicaciones se benefician de disponer de SMT, las diferentes propiedades de los hilos ejecutados pueden desbalancear la asignación de recursos entre los mismos, disminuyendo los beneficios de la ejecución multihilo. Por otro lado, el problema con la memoria está aún presente en los procesadores SMT. Estos procesadores alivian algunos de los problemas de latencia provocados por la lentitud de la memoria con respecto a la CPU. Sin embargo, hilos con grandes cargas de trabajo y con altas tasas de fallos en las caches son unas de las mayores dificultades de los procesadores SMT. Estos hilos intensivos en memoria tienden a crear importantes problemas por la contención de recursos. Por ejemplo, pueden llegar a bloquear recursos críticos debido a operaciones de larga latencia impidiendo no solo su ejecución, sino el progreso de la ejecución de los otros hilos y, por tanto, degradando el rendimiento general del sistema.
El principal objetivo de esta tesis es aportar soluciones novedosas a estos problemas y que mejoren el rendimiento de los procesadores SMT. Para conseguirlo, proponemos los Runahead Threads (RaT) aplicando una ejecución especulativa basada en runahead. RaT es un mecanismo alternativo a las políticas previas de gestión de recursos las cuales usualmente restringían a los hilos intensivos en memoria para conseguir más productividad.
La idea clave de RaT es transformar un hilo intensivo en memoria en un hilo ligero en el uso de recursos que progrese especulativamente. Así, cuando un hilo sufre de un acceso de larga latencia, RaT transforma dicho hilo en un hilo de runahead mientras dicho fallo está pendiente. Los principales beneficios de esta simple acción son varios. Mientras un hilo está en runahead, éste usa los diferentes recursos compartidos sin monopolizarlos o limitarlos con respecto a los otros hilos. Al mismo tiempo, esta ejecución especulativa realiza prebúsquedas a memoria que se solapan con el fallo principal, por tanto explotando el paralelismo a nivel de memoria y mejorando el rendimiento.
RaT añade muy poco hardware extra y complejidad en los procesadores SMT con respecto a su implementación. A través de un mecanismo de checkpoint y lógica de control adicional, podemos dotar a los contextos hardware con la capacidad de ejecución en runahead. Por medio de RaT, contribuímos a aliviar simultaneamente dos problemas en el contexto de los procesadores SMT. Primero, RaT reduce el problema de los accesos de larga latencia en los SMT mediante el paralelismo a nivel de memoria (MLP). Un hilo prebusca datos en paralelo en vez de estar parado debido a un fallo de L2 mejorando su rendimiento individual. Segundo, RaT evita que los hilos bloqueen recursos bajo fallos de larga latencia. RaT asegura que el hilo intensivo en memoria recicle más rápido los recursos compartidos que usa debido a la naturaleza de la ejecución especulativa.
La principal limitación de RaT es que los hilos especulativos pueden ejecutar instrucciones extras cuando no realizan prebúsqueda e innecesariamente consumir recursos de ejecución en el procesador SMT. Este inconveniente resulta en hilos de runahead ineficientes pues no contribuyen a la ganancia de rendimiento e incrementan el consumo de energía debido al número extra de instrucciones especulativas. Por consiguiente, en esta tesis también estudiamos diferentes soluciones dirigidas a solventar esta desventaja del mecanismo RaT. El resultado es un conjunto de soluciones complementarias para mejorar la eficiencia de RaT en términos de consumo de potencia y gasto energético.
Por un lado, mejoramos la eficiencia de RaT aplicando ciertas técnicas basadas en el análisis semántico del código ejecutado por los hilos en runahead. Proponemos diferentes técnicas que analizan y controlan la utilidad de ciertos patrones de código durante la ejecución en runahead. Por medio de un análisis dinámico, los hilos en runahead supervisan la utilidad de ejecutar los bucles y subrutinas dependiendo de las oportunidades de prebúsqueda. Así, RaT decide cual de estas estructuras de programa ejecutar dependiendo de la información de utilidad obtenida, decidiendo entre parar o saltar el bucle o la subrutina para reducir el número de las instrucciones no útiles. Entre las técnicas propuestas, conseguimos reducir las instrucciones especulativas y la energía gastada mientras obtenemos rendimientos similares a la técnica RaT original.
Por otro lado, también proponemos lo que denominamos hilos de runahead eficientes. Esta propuesta se basa en una técnica más fina que cubre todo el rango de ejecución en runahead, independientemente de las características del programa ejecutado. La idea principal es averiguar "cuando" y "durante cuanto" un hilo en runahead debe ser ejecutado prediciendo lo que denominamos distancia útil de runahead. Los resultados muestran que la mejor de estas propuestas basadas en la predicción de la distancia de runahead reducen significativamente el número de instrucciones extras así como también el consumo de potencia. Asimismo, conseguimos mantener los beneficios de rendimiento de los hilos en runahead, mejorando de esta forma la eficiencia energética de los procesadores SMT usando el mecanismo RaT.
La evolución de RaT desarrollada durante toda esta investigación nos proporciona no sólo una propuesta orientada a un mayor rendimiento sino también una forma eficiente de usar los recursos compartidos en los procesadores SMT en presencia de operaciones de memoria de larga latencia.
Dado que los diseños SMT en el futuro estarán orientados a optimizar una combinación de rendimiento individual en las aplicaciones, la productividad y el consumo de energía, los mecanismos basados en RaT aquí propuestos son interesantes opciones que proporcionan un mejor balance de rendimiento y energía que las propuestas previas en esta área.
Research on multithreading topics has gained a lot of interest in the computer architecture community due to new commercial multithreaded and multicore processors. Simultaneous Multithreading (SMT) is one of these relatively new paradigms, which combines the multiple instruction issue features of superscalar processors with the ability of multithreaded architectures to exploit thread level parallelism (TLP). The main feature of SMT processors is to execute multiple threads that increase the utilization of the pipeline by sharing many more resources than in other types of processors.
Shared resources are the key of simultaneous multithreading, what makes the technique worthwhile.
This feature also entails important challenges to deal with because threads also compete for resources in the processor core. On the one hand, although certain types and mixes of applications truly benefit from SMT, the different features of threads can unbalance the resource allocation among threads, diminishing the benefit of multithreaded execution. On the other hand, the memory wall problem is still present in these processors. SMT processors alleviate some of the latency problems arisen by main memory's slowness relative to the CPUs. Nevertheless, threads with high cache miss rates that use large working sets are one of the major pitfalls of SMT processors. These memory intensive threads tend to use processor and memory resources poorly creating the highest resource contention problems. Memory intensive threads can clog up shared resources due to long latency memory operations without making progress on a SMT processor, thereby hindering overall system performance.
The main goal of this thesis is to alleviate these shortcomings on SMT scenarios. To accomplish this, the key contribution of this thesis is the application of the paradigm of Runahead execution in the design of multithreaded processors by Runahead Threads (RaT). RaT shows to be a promising alternative to prior SMT resource management mechanisms which usually restrict memory bound threads in order to get higher throughputs.
The idea of RaT is to transform a memory intensive thread into a light-consumer resource thread by allowing that thread to progress speculatively. Therefore, as soon as a thread undergoes a long latency load, RaT transforms the thread to a runahead thread while it has that long latency miss outstanding. The main benefits of this simple action performed by RaT are twofold. While being a runahead thread, this thread uses the different shared resources without monopolizing or limiting the available resources for other threads. At the same time, this fast speculative thread issues prefetches that overlap other memory accesses with the main miss, thereby exploiting the memory level parallelism.
Regarding implementation issues, RaT adds very little extra hardware cost and complexity to an existing SMT processor. Through a simple checkpoint mechanism and little additional control logic, we can equip the hardware contexts with the runahead thread capability. Therefore, by means of runahead threads, we contribute to alleviate simultaneously the two shortcomings in the context of SMT processor improving the performance. First, RaT alleviates the long latency load problem on SMT processors by exposing memory level parallelism (MLP). A thread prefetches data in parallel (if MLP is available) improving its individual performance rather than be stalled on an L2 miss. Second, RaT prevents threads from clogging resources on long latency loads. RaT ensures that the L2-missing thread recycles faster the shared resources it uses by the nature of runahead speculative execution. This avoids memory intensive threads clogging the important processor resources up.
The main limitation of RaT though is that runahead threads can execute useless instructions and unnecessarily consume execution resources on the SMT processor when there is no prefetching to be exploited. This drawback results in inefficient runahead threads which do not contribute to the performance gain and increase dynamic energy consumption due to the number of extra speculatively executed instructions. Therefore, we also propose different solutions aimed at this major disadvantage of the Runahead Threads mechanism. The result of the research on this line is a set of complementary solutions to enhance RaT in terms of power consumption and energy efficiency.
On the one hand, code semantic-aware Runahead threads improve the efficiency of RaT using coarse-grain code semantic analysis at runtime. We provide different techniques that analyze the usefulness of certain code patterns during runahead thread execution. The code patterns selected to perform that analysis are loops and subroutines. By means of the proposed coarse grain analysis, runahead threads oversee the usefulness of loops or subroutines depending on the prefetches opportunities during their executions. Thus, runahead threads decide which of these particular program structures execute depending on the obtained usefulness information, deciding either stall or skip the loop or subroutine executions to reduce the number of useless runahead instructions. Some of the proposed techniques reduce the speculative instruction and wasted energy while achieving similar performance to RaT.
On the other hand, the efficient Runahead thread proposal is another contribution focused on improving RaT efficiency. This approach is based on a generic technique which covers all runahead thread executions, independently of the executed program characteristics as code semantic-aware runahead threads are. The key idea behind this new scheme is to find out --when' and --how long' a thread should be executed in runahead mode by predicting the useful runahead distance. The results show that the best of these approaches based on the runahead distance prediction significantly reduces the number of extra speculative instructions executed in runahead threads, as well as the power consumption. Likewise, it maintains the performance benefits of the runahead threads, thereby improving the energy-efficiency of SMT processors using the RaT mechanism.
The evolution of Runahead Threads developed in this research provides not only a high performance but also an efficient way of using shared resources in SMT processors in the presence of long latency memory operations. As designers of future SMT systems will be increasingly required to optimize for a combination of single thread performance, total throughput, and energy consumption, RaT-based mechanisms are promising options that provide better performance and energy balance than previous proposals in the field.

The increasing number of cores in both desktops and servers leads to a demand for efficient parallel algorithms. This project focuses on the fundamental collective operation reduce, which merges several arrays into one by applying a binary operation element wise. Several reduce algorithms are evaluated in terms of performance and scalability and a novel algorithm is introduced that takes advantage of shared memory and exploits load imbalance. To do so, the concept of dynamic pair generation is introduced which implies constructing a binary reduce tree dynamically based on the order of thread arrival, where pairs are formed in a lock-free manner. We conclude that the dynamic algorithm, given enough spread in the arriving times, can outperform the reference algorithms for some or all array sizes.

Most people might not reflect upon textiles as anything more than the soft material in our clothes. As a crafts practitioner, I gain knowledge of woven materials that go beyond that. The knowledge of weaving and materials is developing the ideas that form the concept of this project. From the tacit knowledge, derived from years of practically working with textile materials, an intellectual understanding of materials and the worlds they construct is growing. In this project, I decipher my own ideas of the woven structure in order to invite others to experience the universe within textiles. I look at the weave as a structure, built up by small particles in forms of threads. If seeing the weave from a distance, each repeated pattern can in turn be perceived as the smallest element. By seeing woven materials from more than one perspective, I believe that the understanding of the construction itself can develop. As this understanding grows, so does the ability to judge the quality of the material. In this line of thought, the tools used to reflect upon what materials are, how they are made and what they signify, becomes greater. To visualise the knowledge I have of the textile structures I make, I work with a waffle weave structure, together with a dyeing technique called Ikat. I also draw connections between the woven structure and that of a map – as a tool that humans use to understand their surroundings. The use of perspectives and scale is another tool that is used to widen our perception of the world around us. In order to create an experience of the universe within textiles and to invite others into that world, I draw parallels between the miniature scale of the woven material and larger, architectural structures. The final outcome of this project is a textile installation, consisting of three weavings that together form a larger construction. The construction is open for people to enter and experience. Inside the construction a smaller woven piece is presented as a map over the woven world. This weaving initially contains the same information as the large structure, but on a much smaller scale.

Image no. 16 has been removed due to copyright reasons. A link to the image can be found in the List of References

Just as a strand of thread is composed of many smaller threads, so too are there many factors in a single musical moment. Threads of the Moment explores three of these factors: the roles of composer, performer, and listener. The first movement “Composer” seeks to reflect the often messy and disorganized compositional process. Contrary to popular belief, it is not as simple as putting notes on a page and calling that "music.” To compose one must explore and experiment with every sound, big or small, and find the beauty in each so that those sounds can be brought together. There are times where the sounds blend and complement one another, but at other times they create sharp contrasts and dissonance as the composer seeks to find music within the chaotic exploration. The second movement “Performer” explores the idea of a performer being one who interprets and presents the music of the composer. However, while the performer does play based on the composer’s intentions and instructions, there is also room for interpretation. A performer brings new life to a piece by discovering new potential within it and adding his or her voice. To reflect this the cellist acts as the composer, at first leading and inspiring the bass clarinet as the performer, but later the bass clarinet starts to branch off and finds its own interpretation of the melody that it expands on. The final movement looks at the role of listener not only in regards to the audience, but also to the performers themselves who listen to one another’s parts. No one hears the music the exact same way and there are times when a listener is fully engaged, but other times the listener begins to “drift” and lose themselves in the music. For this movement this is reflected in the clarity of certain sections in regards to melody that fractures and enters into hazier sections where the performers are in their own worlds, and it ends with one last thought from each of them.

This thesis considers the problem of recovering from failures of distributable threads with assured timeliness. When a node hosting a portion of a distributable thread fails, it causes orphansâ i.e., thread segments that are disconnected from the threadâ s root. A termination model is considered for recovering from such failures. In this model the orphans must be detected and cleaned up, and failure-exception notification must be delivered to the farthest, contiguous surviving thread segment for resuming thread execution. Two real-time scheduling algorithms (AUA and HUA) and three distributable thread integrity protocols (TPR, D-TPR and W-TPR) are presented. We show that AUA combined with any of the protocols presented bounds the orphan cleanup and recovery time, thereby bounding thread starvation durations and maximizing the total thread accrued timeliness utility. The algorithms and the protocols are implemented in a real-time middleware that supports distributable threads. The experimental studies with the implementation validate the algorithm/protocolsâ time-bounded recovery property and confirm their effectiveness.
Master of Science

Fine screw threads are widely used for the bolted joints under severe running conditions. It is well known that they are effective to prevent thread loosening due to fine pitch. As for other mechanical characteristics, it has been reported in the previous paper using complex stress functions that the stress concentration at bolt thread root is higher than coarse screw threads and the fatigue strength of threaded fasteners shows a minimum value for varying pitch. However, the latter is questionable since the calculations were conducted under lots of hypotheses. In this study, stress concentration and stress amplitude along thread root are evaluated by three-dimensional finite element analysis, in which numerical models of the bolted joints are constructed so as to accurately represent the effect of thread helical geometry. It is shown that the stress concentration at thread root of fine screw threads is higher than that of coarse screw threads, and the maximum stress amplitude is likely to be lower on the contrary. Meanwhile, it is sometimes recognized that clamping forces of fine screw threads are smaller comparing to those of coarse screw threads when tightened with same torque. To clarify this contradictory phenomenon, tightening experiments are conducted, and it is found that the difference of the energy needed for tightening screw threads is found to be the major cause.

There are two types of combination between external and internal threads used in threaded pipe connections for pressure piping specified in industrial standards like JIS as well as ISO. One is the combination that taper external thread of pipe is engaged with taper internal thread of a fitting. The other is that taper external thread of pipe is engaged with parallel internal thread of a fitting. Taper thread is always used for external thread outside the pipe wall. Both taper thread and parallel one are applicable to internal thread inside the fittings. This paper evaluates the mechanical behaviors of threaded pipe-socket joints (or pipe-coupling joints) and the difference due to the thread type combinations by means of axisymmetric finite element analysis for 3/4” and 3” joints. The analysis shows that the taper-taper threads combination establishes the full-length contact over the engaged threads but the taper-parallel has only a pair of threads in contact at the 1st engaged thread from the end of socket, and the difference results in the different behaviors of the joints. Stress and strain pattern also completely differ due to the difference in the engaged thread length. No significant effect of the size has been found in the present analysis for 3/4”and 3” joints. Experimental tightening tests and pressure leak tests have also been carried out for 3/4” and 3” joints with taper-taper threads combination. The measured experimental stress for 3/4” joints has shown an agreement with the simulated one fairly well. The pressure leak tests have demonstrated that the taper-taper threaded pipe-socket joints can hold internal pressure without leakage without using thread seal tape or jointing compound under low-pressure service condition. The 3/4” joints have started leaking at 1–4MPaG of internal pressure. The 3” joints haven’t shown leakage even at 6MPaG of internal pressure applied.

Abstract In this article, we describe the development of a precise analytical model allowing to estimate the thread stripping of nuts. Initially, we carried out a modeling by finite elements of the threads stripping using an axisymmetric model and a criterion of rupture by damage. This modeling enabled us to study the various parameters which influence the behavior of a threaded assembly. To do so, we established an experimental design to know the most significant parameters. The result enables us to propose a simple rule for the optimization of the threaded assemblies whatever metallic materials of bolt and nut. We carried out tests of nuts threads stripping in order to validate this model. The estimated results are very close to those obtained by the tests.

To prescribe simulative contact pressures in benchtop wear tests on materials and lubricants for threads of lead screws, it is necessary to understand how applied load is distributed over those threads. While in threaded fasteners it is known that the first engaged nut thread carries the greatest load and experiences the highest contact pressure, in a lead screw application with considerable sliding this most heavily nut thread will correspondingly wear most rapidly. This suggests instead an eventually uniform steady-state load distribution over the nut threads that should be considered in arriving at a lower contact pressure for simulative wear testing. A model is therefore developed for this coupled evolution of thread load distribution and wear.

A parametric program designed for modeling tapered, trapezoidal threaded connections is used in combination with Abaqus to investigate the behavior of couplings subjected to static load combinations containing make-up, axial tension and internal pressure. Three criteria are defined and used to quantify the performance of the connection: load distribution, helical gap size between the threads and the amount of global plasticity. From these parameters, the load distribution provides valuable information about the effectiveness of the load bearing characteristics of the thread and can be used to detect possible overstressing of the connection. The helical gap size is used to estimate its tendency to provide a leak tight thread seal, while the global plasticity reflects the total amount of plastic deformation within the connection. During the investigation, the effects of taper angle, load flank angle, wall thickness, size of threads and initial thread clearance are considered. The presented modeling approach consists of three parts. First, the optimal make-up position for a trapezoidal threaded 4.5 inch TN80 connection is calculated using the plasticity criterion. Next, the results for the three performance parameters as a function of both axial tension and internal pressure are discussed. Finally, after investigating the various isolated effects induced by geometric changes, a newly defined, enhanced threaded geometry is suggested and compared with the standardized API-buttress thread.

When the relative strength ratio of nut-to-bolt thread is high, the weaker of the two threads will deflect under the relatively stiff action of the other. The rules of the ASME B1.1-1989 provide general design rules for designing non-critical threaded joints. Most threaded joint designs are based on these rules. In most cases, the strengths of the stud and the nut are about the same. This paper addresses plastic deformation and strain in the threaded part of a component (stud) whose strength is about 7 times more than the mating threads. An axisymmetric finite element analysis was performed using nonlinear material properties and nonlinear contact elements between the surfaces of the threads. The results were used to calculate the collapse load for the thread following the rules of Appendix F of the ASME B&PV. It was found that the collapse (maximum allowed) load calculated using this nonlinear finite element approach and Appendix F of ASME code is 50% higher than the load calculated using the conventional elastic methods given in the ASME code rules would be acceptable.

There are two types of pipe threads, i.e., parallel and tapered ones. The former is used for mechanically connecting hollow cylinder-shaped structures, and the latter is usually employed for connecting thin pipes and tubes. The primary function required for taper pipe threads is to prevent the leakage of contained fluids. In order to ensure the sealing performance, target taper pipe threads need to be tightened with proper conditions. However, it seems that a standard tightening guideline with sufficient mechanical background has not been established. In this paper, using helical thread models, the relationship between assembly torque and rotation angle of threaded pipe is studied by FEA. The relationship between rotation angle and radial contact force between male and female threads, which is regarded as an index of the sealing performance, is also evaluated in like manner. In the numerical calculations, finite element analyses are performed as elastic and elastic-plastic problems, in which nominal dimeter of threads, pipe wall thickness and coefficient of friction on the thread contact surface are changed systematically, aiming at the establishment of a practical tightening guideline. Additionally, a simple method is proposed to evaluate the contact force between male and female threads, using elementary theory of solid mechanics. It is shown that the simple method can predict the contact force with sufficient accuracy, comparing to the calculation results by FEA.

The stress concentration factor (SCF) for the roots of screw threads in bolted joints under static loadings is analyzed using 3-D elastic FEM taking account the spiral of screw threads. At first, the stress states at the roots of screw threads in initial clamping state in a bolted joint where two hollow cylinders were clamped with a bolt and a nut were analyzed in initial clamping. The elastic FEM result of SCF for the first root was obtained as SCF=3.2. When the bolt was clamped in initial clamping (preload) at the 60 % of bolt yield stress, the plastic deformations were found at the first and the second roots, and non-engaged screw threads. It was found that as the external tensile loads increased, the development in plastic deformation region increased from the first root to the other roots as well as the non-engaged screw threads. It was found that the rupture occurred from the non-engaged screw threaded part while the plastic deformation increased at each root of screw threads. The numerical result was coincided with the experimental result. In the experiments, it was observed that the rupture occurred from the non-engaged screw thread and not from the first root of screw thread. Also, the bolt fatigue was predicted from FEM and it was shown that a fatigue fracture occurred from the first root.

For the standard thread, severe stress concentration appears in the root of first several threads which share the major part of bolt load, and this is also an important issue in the design of the main bolt thread in the High Temperature Gas-cooled Reactor’s (HTGR’s) Reactor Pressure Vessel (RPV). The linear crest-cutoff method (LCCOM) linearly cuts down the height of the engaged threads near the bolt head, and it could reduce the stress concentration at the roots of first several threads. However, as revealed in finite element simulation, when there are as many as forty threads in the bolt, even though the axial force shared by the first thread could be decreased by LCCOM, the axial force shared by subsequent threads are still very high, which are often larger than that by the first thread. To settle this problem, a nonlinear crest-cut-off method (NCCOM) is proposed, which employs the curved thread profile of quadratic polynomial function, instead of tapered profile of linear function in LCCOM. The proposed curved thread profile has one additional degree of freedom, and it could also be degenerated to tapered profile. As for the main bolt of forty threads in the HTGR’s RPV, the suitable parameters of curved profile are determined by the intensive numerical simulations. The results show that the proposed NCCOM yields lower axial force of the first several threads, and produces lower stress at the roots of threads in the bolt compared with LCCOM.

Technical report on a project intended to quantify natural gas losses in storage wells attributable to threaded casing connectors. Tests were conducted on a simulation apparatus of 5.5-inch K-55 casing using API 8 Round, Long, and Short threaded connections and a representative premium connection.

In November 2020 Oxfam and SOAS facilitated an online high-level event to bring together African and international policy and public-health professionals to discuss their experiences during the COVID-19 pandemic, and offer insights into strategies and policies they have enacted in their respective contexts. Speakers tackled a wide range of issues, including government strategies and policies implemented, public health messaging and community engagement, varying threads of intersectionality and an honest discussion about gaps and additional support. This ‘outcomes’ paper draws out the key themes, trends and recommendations emerging from the discussions to inform a people-not-profit-centric Covid response.