979 resultados para ROTATING SPIRALS


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A challenge for the clinical management of advanced Parkinson’s disease (PD) patients is the emergence of fluctuations in motor performance, which represents a significant source of disability during activities of daily living of the patients. There is a lack of objective measurement of treatment effects for in-clinic and at-home use that can provide an overview of the treatment response. The objective of this paper was to develop a method for objective quantification of advanced PD motor symptoms related to off episodes and peak dose dyskinesia, using spiral data gathered by a touch screen telemetry device. More specifically, the aim was to objectively characterize motor symptoms (bradykinesia and dyskinesia), to help in automating the process of visual interpretation of movement anomalies in spirals as rated by movement disorder specialists. Digitized upper limb movement data of 65 advanced PD patients and 10 healthy (HE) subjects were recorded as they performed spiral drawing tasks on a touch screen device in their home environment settings. Several spatiotemporal features were extracted from the time series and used as inputs to machine learning methods. The methods were validated against ratings on animated spirals scored by four movement disorder specialists who visually assessed a set of kinematic features and the motor symptom. The ability of the method to discriminate between PD patients and HE subjects and the test-retest reliability of the computed scores were also evaluated. Computed scores correlated well with mean visual ratings of individual kinematic features. The best performing classifier (Multilayer Perceptron) classified the motor symptom (bradykinesia or dyskinesia) with an accuracy of 84% and area under the receiver operating characteristics curve of 0.86 in relation to visual classifications of the raters. In addition, the method provided high discriminating power when distinguishing between PD patients and HE subjects as well as had good test-retest reliability. This study demonstrated the potential of using digital spiral analysis for objective quantification of PD-specific and/or treatment-induced motor symptoms.

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■ Human well-being has several key components: the basic material needs for a good life, freedom and choice, health, good social relations, and personal security. Well-being exists on a continuum with poverty, which has been defined as"pronounced deprivation in well-being."
■ How well-being and ill-being, or poverty, are expressed and experienced is context- and situation-dependent, reflecting local social and personal factors such as geography, ecology, age, gender,and culture.These concepts are complex and value-laden.
■ Ecosystems are essential for human well-being through their provisioning, regulating, cultural, and supporting services. Evidence in recent decades of escalating human impacts. on ecological systems worldwide raises concerns about the consequences of ecosystem changes for human well-being.
■ Human well-being can be enhanced through sustainable human interaction with ecosystems with the support of appropriate instruments, institutions, organizations, and technology. creation of these through participation and transparency may contribute to people's freedoms and choices and to increased economic, social,and ecological security.
■ Some believe that the problems from the depletion and degradation of ecological capital can be largely overcome by the substitution of physical and human capital. Others believe that there are more significant limits to such substitutions.The scope for substitutions varies by socioeconomic status.
■ We identify direct and indirect pathways between ecosystem change and human well-being,whether it be positive or negative.lndirect effects are characterized by more complex webs of causation, involving social, economic, and political threads. Threshold points exist beyond which rapid changes to human well-being can occur.
■ Indigent poorly resourced, and otherwise disadvantaged communities are generally the most vulnerable to adverse ecosystem change. Spirals, both positive and negative, can occur for any population, but the poor are more vulnerable.      
■ Functioning institutions are vital to enable equitable access to ecosystem services. lnstitutions sometimes fail or remain undeveloped because of powerful individuals or groups. Bodies that mediate the distribution of goods and services may also be appropriated for the benefit of powerful minorities.
■ For poor people, the greatest gains in well-being will occur through more equitable and secure access to ecosystem services. In the long run, the rich can contribute greatly to human well-being by reducing their substantial impacts on ecosystems and by facilitating greater access to ecosystem services by the poor.
■ We argue ecological security warrants recognition as a sixth freedom of equal weight with participative freedom, economic   facilities, social opportunities, transparency guarantees, and protective security.

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A model of a yam package is established for a ring spinning system. The yarn layer, surface area, and mass of the yam package are formulated with respect to the diameters of the empty bobbin and full yarn package, yarn count, and yarn winding-on time. Based on the principles of dynamics and aerodynamics, models of the power requirements for overcoming the skin friction drag, increasing the kinetic energy of the yarn package (bobbin and wound yarn), and overcoming the yarn wind-on tension are developed. The skin friction coefficient on the surface of a rotating yam package is obtained from experiment. The power distribution during yam packaging is discussed based on a case study. The results indicate that overcoming the skin friction drag during yarn winding consumes the largest amount of energy. The energy required to overcome the yarn wind-on tension is also significant.

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The skin friction coefficient on the surface of a rotating yarn package affects the power required to drive the package. This paper examines the relationship between the skin friction coefficient on the package surface and its diameter and rotating speed, based on the fundamentals of aerodynamics and the experimental results of power consumption. Skin friction coefficients on the surfaces of an airplane, car top, and yarn package are discussed. The results indicate that the skin friction coefficient on the package surface without hairiness depends on the package diameter and spindle speed only. The skin friction coefficient on the yarn package surface is about three times that on the top surface of a car, and is about twenty times that on an airplane surface. The power consumed to overcome skin friction drag is more than that consumed to drive the spindle if the spindle speed is very slow. However, the situation reverses when the spindle speed is fast.

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A compression test with rotating dies was employed to estimate the friction factor between aluminum samples and steel tooling during large plastic deformations. A cylindrical workpiece was compressed under dry and cold conditions. The magnitudes of torque and normal force were measured and
the average friction factor was calculated using the Coulomb friction law. It was found that under certain conditions the friction increased with increasing angular velocity of the die. This finding led to the conclusion that the choice of die rotation speed is important in interpreting the results from the twist compression test.

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Yarn tension is a key factor that affects the efficiency of a ring spinning system. In this paper, a specially constructed rig, which can rotate a yarn at a high speed without inserting any real twist into the yarn, was used to simulate a ring spinning process. Yarn tension was measured at the guide-eye during the simulated spinning of different yarns at various balloon heights and with varying yarn length in the balloon. The effect of balloon shape, yarn hairiness and thickness, and yarn rotating speed, on the measured yarn tension, was examined. The results indicate that the collapse of balloon shape from single loop to double loop, or from double loop to triple etc, lead to sudden reduction in yarn tension. Under otherwise identical conditions, a longer length of yarn in the balloon gives a lower yarn tension at the guide-eye. In addition, thicker yarns and/or more hairy yarns generate a higher tension in the yarn, due to the increased air drag acting on the thicker or more hairy yarns.

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Fiber surface morphologies and associated internal structures are closely related to its properties. Unlike other fibers including cotton, bast fibers possess transverse nodes and fissures in cross-sectional and longitudinal directions. Their morphologies and associated internal structures were anatomically examined under the scanning electron microscope. The results showed that the morphologies of the nodes and the fissures of bast fibers varied depending on the construction of the inner fibril cellular layers. The transverse nodes and fissures were formed by the folding and spiralling of the cellular layers during plant growth. The dimensions of nodes and fissures were determined by the dislocations of the cellular layers. There were also many longitudinal fissures in bast fibers. Some deep longitudinal fissures even opened the fiber lumen for a short way along the fiber. In addition, the lumen channel of the bast fibers could be disturbed or disrupted by the nodes and the spirals of the internal cellular layers. The existence of the transverse nodes and fissures in the bast fibers could degrade the fiber mechanical properties, whereas the longitudinal fissures may contribute to the very rapid moisture absorption and desorption.

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It is generally accepted that institutional problems have severely constrained development in many countries regardless of significant achievements in technology and other reforms. Both the Old and New Institutional Economics have relevance in understanding the lack of progress in many countries in Asia and Africa. Institutions generally refer to the "framework within which human interactions take place. Two major strands of NIE are the transaction costs and the collective action approach. The NIE implies that traditional rural institutions such as user groups, rotating credit and irrigation associations, interlinked credit etc. are institutions that have emerged in place of the market due to lower transactions costs. The successful management of common property resources such as water, forests, wetlands etc using local arrangements imply that institutions need to be interpreted in broader terms and the simple dichotomy of market or the government is too limited to understand the development process. New thinking is required in developing institutions that are structurally suited for management at the local level. Such an approach will have better chance to succeed compared to a process based upon the market.

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Air drag on yarn and package surfaces affects yarn tension, which in turn affects energy consumption and ends-down in ring spinning. This study investigated the effects of yarn hairiness on air drag in ring spinning. Theoretical models of skin friction coefficient on the surface of rotating yarn packages were developed. The predicted results were verified with experimental data obtained from cotton and wool yarns. The results show that hairiness increases the air drag by about one-quarter and one-third for the rotating cotton and wool yarn packages, respectively. In addition, yarn hairiness increases the air drag by about one-tenth on a ballooning cotton yarn.

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High energy consumption remains a key challenge for the widely used ring spinning system. Tackling this challenge requires a full understanding of the various factors that contribute to yarn tension and energy consumption during ring spinning. In this paper, we report our recent experimental and theoretical research on air drag, yarn tension and energy consumption in ring spinning. A specially constructed rig was used to simulate the ring spinning process; and yarn tension at the guide-eye was measured for different yarns under different conditions. The effect of yarn hairiness on the air drag acting on a rotating yarn package and on a ballooning yarn was examined. Models of the power requirements for overcoming the air drag, increasing the kinetic energy of the yarn package (bobbin and wound yarn) and overcoming the yarn wind-on tension were developed. The ratio of energy-consumption to yarn-production over a full yarn package was discussed. A program to simulate yarn winding in ring spinning was implemented, which can generate the balloon shape and predict yarn tension under a given spinning condition. The simulation results were verified with experimental results obtained from spinning cotton and wool yarns.

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We show that shear-free perfect fluids obeying an equation of state p = (γ − 1)μ are non-rotating or non-expanding under the assumption that the spatial divergence of the magnetic part of the Weyl tensor is zero.

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Shift workers have a higher rate of negative health outcomes than day shift workers. Few studies however, have examined the role of difference in workplace environment between shifts itself on such health measures. This study investigated variation in organizational climate across different types of shift work and health outcomes in nurses. Participants (n = 142) were nursing staff from a metropolitan Melbourne hospital. Demographic items elicited the type of shift worked, while the Work Environment Scale and the General Health Questionnaire measured organizational climate and health respectively. Analysis supported the hypotheses that different organizational climates occurred across different shifts, and that different organizational climate factors predicted poor health outcomes. Shift work alone was not found to predict health outcomes. Specifically, permanent night shift workers had significantly lower coworker cohesion scores compared with rotating day and evening shift workers and significantly higher managerial control scores compared with day shift workers. Further, coworker cohesion and involvement were found to be significant predictors of somatic problems. These findings suggest that differences in organizational climate between shifts accounts for the variation in health outcomes associated with shift work. Therefore, increased workplace cohesion and involvement, and decreased work pressure, may mitigate the negative health outcomes of shift workers.

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In the current work, constitutive models are developed to describe the cyclic hardening and softening led by the strain path chaneg.  The contribution of deformation conditions such as drawing and extrusion speed, cyclic rotating angle on the drawing and extrusion force will be investigated.  The development of such constitutive models will provide insight into the optimization of operation conditions to explore the potential of industrial applications.

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A series of experiments are reported for compression of an aluminum cylinder with monotonic and cyclic die rotation. When the die is monotonically rotated, a higher angular velocity or a lower compression speed of the tool leads to a greater load reduction in comparison of that seen with a stationary die. The test results also show that cyclic die rotation causes a cyclic fluctuation in the load-displacement curve. During the die deceleration phase, the compression load increases until it reaches the level obtained in conventional compression with stationary dies. However, the compression load is observed to reduce to levels lower than those obtained in monotonic rotating compression tests during the die acceleration phase. The frequency of rotating direction change seems to affect the position of load peaks only, not the amplitude of the peaks.

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The ring spinning process has been used to produce fine and high quality staple fibre yarns. The stability of the rotating yarn loop (i.e. balloon) between the yarn-guide and the traveller-ring is crucial to the success and economics of this process. Balloon control rings are used to contain the yarn-loop, by reducing the yarn tension and decreasing the balloon flutter instability. Flutter instability here refers to the uncontrolled changes in a ballooning yarn under dynamic forces, including the air drag. Due to the significant variation in the length and radius of the balloon during the bobbin filling process, the optimal location for the balloon control ring is not easily determined. In order to address this difficulty, this study investigates the variation in the radius of a free balloon and examines the effect of balloon control rings of various diameters at different locations on yarn tension and balloon flutter stability. The results indicate that the maximum radius of a free balloon and its corresponding position depend not only on the yarn-length to balloon-height ratio, but also on yarn type and count. A control ring of suitable radius and position can significantly reduce yarn tension and decrease flutter instability of free single-loop balloons. While the balloon control rings are usually fixed to, and move in sinc with, the ring frame, results reported in this study suggest that theoretically, a balloon control ring that always remains approximately half way between the yarn-guide and the ring rail during spinning can lead to significant reduction in yarn tension.