Kinds Of Fatigue Research Articles

THE RELATIONSHIP BETWEEN FATIGUE AND DRIVING PERFORMANCE: A REVIEW AND DIRECTIONS FOR FUTURE RESEARCH

Objectives: The purpose of this article is to review the empirical studies conducted on the relationship between fatigue and driving performance in different fields and its applicability in Malaysia’s oil and gas industry. Methods: We investigated the relationship between driving fatigue and driving performance by reviewing published works on the subject matter in the past studies. We then highlighted the various kinds of fatigue that influence driving performance with indications of past works and future directions. Results: It was found that the previous studies have empirically and otherwise confirmed the existing relationship between driving fatigue and driving performance. However, some crucial areas contributing to the performance of drivers have not been thoroughly examined thus requiring further investigation, particularly with the use of a psychomotor vigilance test (PVT-192). The knowledge derived could facilitate the productivity and cost-effectiveness of the oil and gas sector as the relationship between fatigue and driving performance has been noted to be different across sectors. Conclusions: The existing knowledge points to the need to study factors that lead to fatigue in order to enhance the driving performance of the drivers serving the Malaysian oil and gas transportation companies. The factors may be considered in proposing a framework for monitoring and improving the performance of the drivers of oil and gas tankers in an effort to reduce the rate of road accidents.

A macroscopic description of shape memory alloy functional fatigue

Shape memory alloys (SMAs) are smart materials employed in several applications including medical devices, aerospace components, robotics, among others. In many of these applications, devices are subjected to cyclic loading conditions. Based on this, a proper comprehension of fatigue phenomenon is essential for suitable design of systems involving SMA elements. In general, SMAs exhibit two kinds of fatigue: functional fatigue, related to the decrease of the functional properties; and structural fatigue, associated with the nucleation and growth of microcracks that lead to fracture. This paper presents a macroscopic three-dimensional constitutive model to describe functional fatigue on shape memory alloys considering continuum damage perspective. Numerical simulations are compared with experimental results showing the capabilities of the proposed model. In addition, numerical simulations are presented in order to explore the general thermomechanical aspects of SMA functional fatigue, allowing a proper comprehension of phenomenological aspects.

The tyranny of clock time? Debating fatigue in the US truck driving industry

Social theorists frequently claim that clock time—a cold, mechanical, and intensifying culture of time reckoning—has the tendency to dominate “process time”—a warm, humane, and leisurely culture of time-reckoning. This article interrogates this “tyranny of clock time” narrative through an in-depth examination of the fatigue debate in the US truck driving industry. I find that trucking regulators use clock time to encourage rest and recovery. Drivers, meanwhile, are committed to process time in ways that encourage intensification and overwork. Process time culture involves its own forms of time discipline that are related to power, exploitation, and overwork in surprising ways. Yet even though the normative ends of the two time orientations are reversed in this case, I still find that clock time is tyrannical in a certain limited sense. Clock time disrupts the rhythms of the labor process leading to work scenarios that drivers find fatiguing. In their efforts to use clock time to regulate fatigue, then, trucking regulators have actually created new kinds of fatigue. The tyranny of clock time narrative is thus challenged and supported in ways that refine our understanding of both clock time and process time.

A Study on the Effects of Fatigue Driving and Drunk Driving on Drivers’ Physical Characteristics

Objective: The purpose of this study was to analyze the effects of fatigue driving and drunk driving on drivers’ physical characteristics; to analyze the differences in drivers’ physical characteristics affected by different kinds of fatigue; and to compare the differences in the effects of the 2 driving states, fatigue driving and drunk driving.Methods: Twenty-five participants’ physical characteristics were collected under 5 controlled situations: normal, tired driving, drowsy driving, drowsiness + tired driving, and drunk driving. In this article, fatigue driving refers to tiredness and drowsiness and includes 3 situations: tired driving, drowsy driving, and drowsiness + tired driving. The drivers’ physical characteristics were measured in terms of 9 parameters: systolic blood pressure (SBP), heart rate (HR), eyesight, dynamic visual acuity (DVA), time for dark adaption (TDA), reaction time to sound (RTS), reaction time to light (RTL), deviation of depth perception (DDP), and time deviation of speed anticipation (TDSA). They were analyzed using analysis of variance (ANOVA) with repeated measures. Binary logistical regression analysis was used to explain the relationship between drivers’ physical characteristics and the two driving states.Results: Most of the drivers’ physical characteristic parameters were found to be significantly different under the influence of different situations. Four indicators are significantly affected by fatigue driving during deep fatigue (in decreasing order of influence): HR, RTL, SBP and RTS. HR and RTL are significant in the logistical regression model of the drowsiness + tired driving situation and normal situations. Six indicators of the drivers’ physical characteristics are significantly affected by drunk driving (in decreasing order of influence): SBP, RTL, DDP, eyesight, RTS, and TDSA. SBP and DDP have a significant effect in the logistical regression model of the drunk driving situation and the normal situation.Conclusions: Both fatigue driving and drunk driving are found to impair drivers’ physical characteristics. However, their impacts on the parameters SBP, HR, eyesight, and TDSA are different. A driver's physical characteristics will be impaired more seriously when he continues driving while drowsy, compared to driving under normal situation. These findings contribute to the current research on identifying drivers’ driving state and quantifying the effects of fatigue driving and drunk driving on driving ability and driving behavior.

SU-E-I-62: Investigation of Dominant Factors Affecting Fatigue in Image Reading of Radiologists.

To investigate dominant factors affecting fatigue in image reading of radiologists. Two kinds of fatigue were assessed in this study. One was fatigue in the central nervous system evaluated by the critical fusion frequency (CFF). The other was eye fatigue evaluated by a score determined from a questionnaire based on the oculomotor strain subscale from the Simulator Sickness Questionnaire (SSQ). When fatigue increases, the CFF and the SSQ score indicate low and high values, respectively. The fatigue of seventeen radiologists was assessed before and after their daily image reading. The reading times and the numbers of images were different among the assessments, and ranged about 1.5 - 5.0 hours and 1,000 - 12,000 images, respectively. The assessments of fatigue were repeated four times for each radiologist on different days. Finally, the measurements of the two kinds of fatigue were analyzed in terms of years of experience, age, sleeping time the previous night, ambient light conditions, reading time, and the numbers of interpreted images, series, and cases. The CFF and SSQ score after image reading were significantly lower and higher than those measured before image reading, respectively. Younger and less experienced radiologists indicated a higher level of fatigue than older and more experienced radiologists in both the CFF and the SSQ score. When radiologists interpreted clinical images for longer hours, the SSQ score tended to be higher. On the other hand, there was little incremental difference in the CFF among different lengths of reading time. No obvious differences were observed in the other items. Less experience with reading images, a younger age, and a longer reading time could be dominant factors affecting fatigue in image reading.

Effects of DLC on Fatigue Properties of Eutectoid Steel

Diamond-like carbon (DLC) is an amorphous hard carbon, which has very high hardness, high resistivity, and dielectric optical properties. Economically and technologically attractive properties have drawn almost unparalleled interest towards the coatings. Eutectoid steel is a kind of material that has been widely used in shafts and various kinds of industrial components. Three kinds of fatigue specimens with different DLC conditions were used in this study. Fatigue test had been performed to investigate the effects of DLC on fatigue properties of eutectoid steel. The fractography was analyzed by a scanning electron microscope (SEM), and surface hardness was also evaluated. The fatigue limits of the DLC coated specimens did notincrease after DLC process, though the compressive residual stress which produced by DLC process can prevent fatigue fracture. According to the results of fatigue test, the optimal DLC method for improving the fatigue properties of eutectoid steel is determined and the relationship between fatigue limits and coating bias are obtained.

Fatigue after spinal cord injury

Objectives To identify variables increasing fatigue following spinal cord injury (SCI) and their functional consequences. Methods A search of the Medline and Reedoc databases with the keywords SCI, fatigue, intrinsic muscular fatigue, chronic fatigue, aging, training, electrostimulation, quality of life and the same words in French. Results Two kinds of fatigue are identified following SCI. Intrinsic fatigue in muscles totally or partially paralysed at the level of or below the spinal cord lesion; this peripheral fatigue is due to denervation, total or partial loss of motoneurons, or histological and metabolical changes in muscle; it is well-defined by electrophysiological technology; spasticity and spasms have little influence on its development; it is reversible in part with long term electrostimulation, but at this time, electroneuroprosthetic techniques do not reduce the excessive energetic cost to stand up and walk. Chronic fatigue appears in the long term following SCI; it is linked with aging, physiological, and psychological deconditioning; some data point to chronic fatigue after SCI similar to post-polio syndrome and chronic fatigue syndrome, which may explain the central nature of the fatigue; training programs could be useful in delaying this chronic fatigue and as a consequence, increasing the latent quality of life. Conclusion Muscular intrinsic fatigue after SCI is always of a peripherical nature in muscles partially or totally paralysed. Chronic fatigue during aging greatly decreases quality of life. Both intrinsic and chronic fatigue could be anticipated by electrostimulation technique on the one hand and long term training on the other.

Fatigue: Towards an analysis and a unified definition

Fatigue is the commonest, yet least understood and most neglected symptom in medicine. A physiological formula for fatigue is proposed, based on the concept of a reduction of the “latent capacity” of cells, tissues and organs whose states are constantly monitored by the brain. Reduced “latent capacity” is postulated as being the sought-after, non-specific alarm signal of the General Adaptation Syndrome of Selye (G.A.S.). The relationship between fatigue and pain is discussed. Reduced “latent capacity” is postulated as being the common thread in the different kinds of fatigue — physiological, pathological, psychogenic, acute and chronic.

Metabolic correlates of fatigue and of recovery from fatigue in single frog muscle fibers.

Fatigue and recovery from fatigue were related to metabolism in single fibers of the frog semitendinosus muscle. The fibers were held at a sarcomere length of 2.3 microm in oxygenated Ringer solution at 15 degrees C and were stimulated for up to 150 s by a schedule of 10-s, 20-Hz tetanic trains that were interrupted by 1-s rest periods, after which they were rapidly frozen for biochemical analysis. Two kinds of fatigue were produced in relation to stimulus duration. A rapidly reversed fatigue occurred with stimulation for under 40 s and was evidenced by a decline in tetanic tension that could be overcome by 1 s of rest. A prolonged fatigue was caused by stimulation for 100-150 s. It was evidenced during stimulation by a fall in tetanic tension that could not be overcome by 1 s of rest, and after stimulation by a reduction, lasting for up to 82 min, in the peak tension of a 200-ms test tetanus. Fiber phosphocreatine (PCr) fell logarithmically in relation to stimulus duration, from a mean of 121 +/- 8 nmol/mg protein (SEM, n = 12) to 10% of this value after 150 s of stimulation. PCr returned to normal levels after 90-120 min of rest. Stimulation for 150 s did not significantly affect fiber glycogen and reduced fiber ATP by at most 15%. It is suggested that the prolonged fatigue caused by 100-150 s of tetanic stimulation was caused by long-lasting failure of excitation-contraction coupling, as it was not accompanied by depletion of energy stores in the form of ATP. One possibility is that H+ accumulated in fatigued fibers so as to interfere with the action of Ca2+ in the coupling process.

尿蛋白の血清学的研究

The urinary protein in case of various kinds of fatigue and hypertension is almost the same as the blood plasma and has all components of the plasma protein. There were no qualitative differences between the urinary protein and the blood plasma protein. This fact can be proved by the experiments of anaphylaxis and that of the filter-paper-electrophoresis.Now according to the filter-paper-experiment, the author can state that the urinary protein of fatigue has comparatively small amount of albumin and large amount of γ-globulin, and the urinary protein of hypertension has the contrary.

Fatigue of Aircraft Materials with Special Reference to Micro-Structure

Of the many kinds of fatigue of materials, this paper deals only with “The fatigue of ductile metals by the imposition of cyclic stresses.” It is the purpose of the paper to show that: —(i)Metals have certain very human attributes.(ii)They have both memory and temperament.(iii)They remember with increasing resentment the stresses which have been imposed upon them.(iv)They are extremely sensitive as to the appropriate moment at which to break.The question arises of why a piece of any ductile metal, other than a ferrous one, free from any abrupt change of section, when subjected to cyclic stresses of any magnitude, however small, ultimately breaks although the maximum stress imposed is one which, if static, it could have borne indefinitely. The answer is—mainly because of its metallographic structure.