Transformer top-oil temperature modeling and simulation

Improving the utilization of transformers requires that the hot-spot temperatures and top-oil temperatures (TOTs) be predicted accurately. The authors' experimentation with various discretization schemes and models proved that many of the linear and nonlinear semiphysical and nonphysical models they were using to predict transformer TOT were correctly modeling the TOT behavior. Their experience convinced them that noisy input data and the absence of data on significant driving variables, not model deficiencies, were frustrating their attempts to reduce the prediction error further. In this paper, they discuss the body of research that led them to these conclusions     

Establishing and managing a network for continuous innovation: Invoking organizational pressure

Social networks in organizations have been identified as important both in terms of increasing our understanding of innovation and for organizations to realize innovation outcomes. While previous studies have informed us of the importance of networks for innovation, we know little of how companies intentionally can design and utilize networks to achieve continuous innovation. The aim of this paper is to explore how a network for continuous innovation can be established and managed. A longitudinal case study has been performed using data covering the establishment and subsequent management of a network for supporting continuous innovation, spanning the product management and R&D department of a large multinational company. The results reveal the potential to use intra‐organizational networks to invoke organizational pressure conducive for making innovation happen. This pressure is induced by autonomy and self‐organizing in the network and consists of reciprocal expectations and demands between the top (management) and the bottom (employees involved in the network) of the organizational hierarchy. Implications for theory and practice are discussed.     

Thermal inactivation of Escherichia coli O157:H7 in cow manure compost

Rates of inactivation of a five-strain mixture of green fluorescent protein-labeled Escherichia coli O157:H7 in autoclaved and unautoclaved commercial cow manure compost with a moisture content of ca. 38% were determined at temperatures of 50, 55, 60, 65, and 70 degrees C. Trypticase soy agar with ampicillin was determined to be the best medium for the enumeration of heat-injured and uninjured cells of green fluorescent protein-labeled E. coli O157:H7. The results obtained in this study revealed that in autoclaved compost, E. coli O157:H7 reductions of ca. 4 log CFU/g occurred within 8 h, 3 h, 15 min, 2 min, and < 1 min at 50, 55, 60, 65, and 70 degrees C, respectively. At 65 and 70 degrees C, considerably less time was required to kill the pathogen in unautoclaved compost than in autoclaved compost. Decimal reduction times (D-values) for autoclaved compost at 50, 55, 60, 65, and 70 degrees C were 137, 50.3, 4.1, 1.8, and 0.93 min, respectively, and D-values for unautoclaved compost at 50, 55, and 60 degrees C were 135, 35.4, and 3.9 min, respectively. Considerable tailing was observed for inactivation curves, especially at 60, 65, and 70 degrees C. These results are useful for identifying composting conditions that will reduce the risk of the transmission of E. coli O157:H7 to foods produced in the presence of animal fecal waste.     

Selective attention deficits and subjective fatigue following traumatic brain injury.

The present study aimed to investigate the relationship between subjective fatigue and selective attention deficits following traumatic brain injury (TBI). Forty-six participants with mild-severe TBI and 46 healthy controls completed fatigue scales (Visual Analogue Scale--Fatigue, Fatigue Severity Scale [FSS] and Causes of Fatigue Questionnaire [COF]), and attentional measures including subtests from the Test of Everyday Attention, and the Complex Selective Attention Task (C-SAT). TBI participants reported greater fatigue on the FSS and COF, performed more slowly on attentional measures, and made more errors on the C-SAT. After controlling for anxiety and depression, fatigue was significantly correlated with performance only on the C-SAT. Findings suggest a relationship between subjective fatigue and impairment on tasks requiring higher order attentional processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microscratching Characterization of the Wear-in of UHMW Polyethylene in Prostheses

A new measurement technique of prosthesis wear by microscratching has been demonstrated. The technique has been applied in a study of the backside wear of a UHMW polyethylene tibial insert of a rotating platform knee prosthesis. Four disc-shaped UHMW polyethylene plugs, prepared with 5-μm deep microscratches, were carefully recessed into the backside of the tibial insert. It was demonstrated that the scratches are not affected by creep under static load. A realistic in vitro wear simulation experiment was performed over 0.8 × 10⁶ flexion cycles. SEM and AFM show that following the experiment the initial microscratches are effectively absent in all four locations with only residual depressions observed. This implies that typically at least 5 μm of polyethylene material was worn over the first 0.8 × 10⁶ cycles by processes other than creep. Evidence from AFM and SEM indicates the in-fill and reintegration of polyethylene wear particles into residual scratch depressions. This supports a two-phase model of the wear process that has been independently confirmed by radioisotope tracing. For an initial wear-in phase, the model implies large, but rapidly decreasing, wear, resulting from abrasive wear and a competition between the loss and the reintegration of wear particles. The in vitro wear-in of the backside may typically produce a wear debris volume of 8.5 mm³. In addition to wear-in, the model assumes a much lower, constant long-term wear rate. The model has been used to correct published backside wear rates for the effects of the wear-in phase. A best estimate of 0.7 mm³/10⁶ cycles has been determined for the long-term in vitro backside wear rate of a tibial insert in a rotating platform design.     

外观时尚前卫,满足电影音乐两大需求HECO(德高)Ambient 44F

配备3款不同风格的前盖板轻松融入不同家居装修 HECO Ambient系列共有3款型号,分别是Ambient11F、Ambient 22F、Ambient 44F.它们在设计上大同小异,配置最多单元的Ambient 44F明显是针对大型家庭影院而设计,而后的Ambient 22F、Ambient11F,则是面向客厅影院...     

Safety in numbers? Investigating Australian driver behaviour,knowledge and attitudes towards cyclists

A key tenet of the safety in numbers theory is that as the number of people cycling increases, more drivers will also be cyclists and therefore will give greater consideration to cyclists when driving. We tested this theory in relation to self-reported behaviour, attitudes and knowledge in relation to cycling. An online survey was conducted of Australian drivers (n = 1984) who were also cyclists (cyclist-drivers) and drivers who did not cycle (drivers). Cyclist-drivers were 1.5 times more likely than drivers to report safe driving behaviours related to sharing the roads with cyclists (95% CI: 1.1–1.9, p < 0.01). Cyclist-drivers had better knowledge of the road rules related to cycling infrastructure than drivers; however knowledge of road rules related to bike lanes was low for both groups. Drivers were more likely than cyclist-drivers to have negative attitudes (e.g. cyclists are unpredictable and repeatedly overtaking cyclists is frustrating). Findings from this study highlight the need for increased education and awareness in relation to safe driving behaviour, road rules and attitudes towards cyclists. Specific recommendations are made for approaches to improve safety for cyclists.     

Influence of three principles of pacing on the temporal organisation of work during cyclic assembly and disassembly tasks

A study was conducted to investigate the influence of different approaches to arranging the pace and temporal organisation of repetitive assembly and disassembly tasks on both average performance and its variability and to compare assembly and disassembly times derived with psychophysical methods to a more traditional methods-time measurement (MTM) approach. The conditions studied were a traditional assembly line arrangement, where assemblies were started at a pace of 110 MTM (repeated on two occasions), a batch condition, where subjects were required to complete 36 assemblies within the total amount of time allowed at 110, MTM and a psychophysical condition, where subjects were allowed to choose their pace (repeated on two occasions). Overall, the results suggest that the mean time spent working in each cycle (the 'on-time') remained fairly constant across conditions, while the idle 'off-time' in between on-times was shorter and of less varied duration in the more autonomous batch and psychophysical conditions. During the second psychophysical (self-paced) condition, subjects completed a significantly higher number of assemblies than during the 110 MTM line condition. The higher pace was achieved through reduction in mean off-times and the potential implications for musculoskeletal risk are discussed. STATEMENT OF RELEVANCE: Higher levels of autonomy over work pace, which intuitively would be beneficial from an ergonomics standpoint, actually led to subjects selecting to organise work such that off-times (idle times) were reduced. In contrast, active 'on' times were not affected much by autonomy. These results point to a reason that piecework would be associated with increased risk for musculoskeletal disorders.     

Differences in day and night shift clinical performance in anesthesiology

OBJECTIVE: This study examined whether anesthesia residents (physicians in training) performed clinical duties in the operating room differently during the day versus at night. BACKGROUND: Fatigue from sleep deprivation and working through the night is common for physicians, particularly during residency training. METHODS: Using a repeated-measures design, we studied 13 pairs of day-night matched anesthesia cases. Dependent measures included task times, workload ratings, response to an alarm light latency task, and mood. RESULTS: Residents spent significantly less time on manual tasks and more time on monitoring tasks during the maintenance phase at night than during the day. Residents reported more negative mood at night than during the day, both pre- and postoperation. However, time of day had no effect on the mood change between pre- and postoperation. Workload ratings and the response time to an alarm light latency task were not significantly different between night and day cases. CONCLUSIONS: Because night shift residents had been awake and working for more than 16 hr, the observed differences in task performance and mood may be attributed to fatigue. The changes in task distribution during night shift work may represent compensatory strategies to maintain patient care quality while keeping perceived workload at a manageable level. APPLICATIONS: Fatigue effects during night shifts should be considered when designing work-rest schedules for clinicians. This matched-case control scheme can also be applied to study other phenomena associated with patient safety in the actual clinical environment.