Stator iron loss of tubular permanent-magnet machines

While methods of determining the iron loss in rotating permanent-magnet (PM) machines have been investigated extensively, the study of iron loss in linear machines is relatively poorly documented. This paper describes a simple analytical method to predict flux density waveforms in discrete regions of the laminated stator of a tubular PM machine, and employs an established iron loss model to determine the iron loss components, on both no load and on load. Analytical predictions are compared with the iron loss deduced from finite-element analyses for two tubular PM machine designs, and it is shown that if a machine has a relatively high electrical loading, the on-load iron loss can be significantly higher than the no-load value

Module failure isolation circuit for paralleled inverters

A module failure isolation circuit is described which senses and averages the collector current of each paralled inverter power transistor and compares the collector current of each power transistor the average collector current of all power transistors to determine when the sensed collector current of a power transistor in any one inverter falls below a predetermined ratio of the average collector current. The module associated with any transistor that fails to maintain a current level above the predetermined radio of the average collector current is then shut off. A separate circuit detects when there is no load, or a light load, to inhibit operation of the isolation circuit during no load or light load conditions

A pilot investigation of load-carrying on the head and bone mineral density in premenopausal, black African women

Although the influence of weight bearing activity on bone mass has been widely investigated in white women, few studies have been conducted in black, African populations. We investigated bone mineral density (BMD) in black South African women, with and without a history of load-carrying on the head. We also investigated whether load carrying may offer protection against low BMD in users of injectable progestin contraception (IPC). Participants were 32 black, South African women (22.4±3.2 yrs). Load carrying history was determined by questionnaire and interview and participants were grouped as load carriers (LC; n=18) or non load carriers (NLC; n=14). Ten women were using IPC and 6 were load-carriers. Total body (TB), lumbar spine (LS) and total hip (H) BMD were measured by dual energy X-ray absorptiometry. There were no differences in BMD between LC and NLC, and after controlling for age and BMI using two-tailed partial correlations. IPC users had lower BMD at all sites compared to non IPC users (p<0.05) and there were no associations between load carrying and BMD in this group. When IPC users were excluded from analysis, LC had higher LS BMD than NLC (p<0.005). Correlations were found between the weight of load carried and LS BMD (r=0.743, p<0.005), and between years of load carrying and LS and TB BMD (r=0.563, r=0.538 respectively; both p<0.05). Load carrying on the head may offer osteogenic benefits to the spine but these benefits did not appear in women using IPC

Hemoglobin A1c Levels Modify Associations between Dietary Acid Load and Breast Cancer Recurrence.

BackgroundMetabolic acidosis promotes cancer metastasis. No prospective studies have examined the association between dietary acid load and breast cancer recurrence among breast cancer survivors, who are susceptible to metabolic acidosis. Hyperglycemia promotes cancer progression and acid formation; however, researchers have not examined whether hyperglycemia can modify the association between dietary acid load and breast cancer recurrence.MethodsWe studied 3081 early-stage breast cancer survivors enrolled in the Women's Healthy Eating and Living study who provided dietary information through 24-h recalls at baseline and during follow-up and had measurements of hemoglobin A1c (HbA1c) at baseline. We assessed dietary acid load using two common dietary acid load scores, potential renal acid load (PRAL) score and net endogenous acid production (NEAP) score.ResultsAfter an average of 7.3 years of follow-up, dietary acid load was positively associated with recurrence when baseline HbA1c levels were ≥ 5.6% (median level) and ≥5.7% (pre-diabetic cut-point). In the stratum with HbA1c ≥ 5.6%, comparing the highest to the lowest quartile of dietary acid load, the multivariable-adjusted hazard ratio was 2.15 (95% confidence interval [CI] 1.34-3.48) for PRAL and was 2.31 (95% CI 1.42-3.74) for NEAP. No associations were observed in the stratum with HbA1c levels were <5.6%. P-values for interactions were 0.01 for PRAL and 0.05 for NEAP.ConclusionsOur study demonstrated for the first time that even at or above normal to high HbA1c levels, dietary acid load was associated with increased risk of breast cancer recurrence among breast cancer survivors.ImpactsOur study provides strong evidence for developing specific dietary acid load guidelines based on HbA1c levels

Load proportional safety brake

This brake is a self-energizing mechanical friction brake and is intended for use in a rotary drive system. It incorporates a torque sensor which cuts power to the power unit on any overload condition. The brake is capable of driving against an opposing load or driving, paying-out, an aiding load in either direction of rotation. The brake also acts as a no-back device when torque is applied to the output shaft. The advantages of using this type of device are: (1) low frictional drag when driving; (2) smooth paying-out of an aiding load with no runaway danger; (3) energy absorption proportional to load; (4) no-back activates within a few degrees of output shaft rotation and resets automatically; and (5) built-in overload protection

Effects of Backpack Load and Trekking Poles on Energy Expenditure During Field Track Walking

This study evaluates the effects of the use of backpack load and trekking poles on feld track walking energy expenditure. Twenty male volunteer pole walkers (age: 22.70 ± 2.89 years; body mass: 77.90 ± 11.19 kg; height: 1.77 ± 0.06 m; percentage of body fat: 14.6 ± 6.0 %) walked at a self-selected pace on a pedestrian feld track over a period of more than six months. Each subject was examined at random based on four walking conditions: non-poles and non-load, with poles and non-load, nonpoles and with load, with poles and with load. Heart rate, oxygen uptake and energy expenditure were continuously recorded by a portable telemetric system. Non-load walking speed was lower during walking with poles when compared with no poles (p ≤ 0.05). Oxygen uptake, energy expenditure and heart rate varied signifcantly across different conditions. Our results suggest that the use of trekking poles does not influence energy expenditure when walking without an additional load, but it can have an effect during backpack load walking. Moreover, our results indicate that the use of trekking poles may not be helpful to lower the exertion perceived by the subjects when walking with an additional load.info:eu-repo/semantics/publishedVersio

Auditory Distractors in the Visual Modality: No Evidence for Perceptual Load Hypothesis or Auditory Dominance

Attention is a valuable resource with limited capacity, so knowing what will distract us during important tasks can be crucial in life. There is a lot of support for the Perceptual Load Hypothesis (PLH) when examining visual distractibility; however, less research has examined if PLH can predict auditory distractibility. Participants in the current study completed three experiments using visual selective attention tasks while being presented with auditory and visual distractions under low/high perceptual loads. In Experiment 1, I took the visual selective attention task from Robinson et al. (2018) and shortened the stimulus presentation while adding a no distractor baseline condition. In Experiment 2, I increased auditory distractor effects by requiring participants to periodically respond to the auditory information. In Experiment 3, I added a working memory task to increase cognitive load. Results showed no support for PLH with auditory distractors in Experiments 1 or 2, and instead showed the opposite pattern, with auditory distractors having a larger effect under high perceptual load (Experiment 2). Results from Experiment 3 show that increasing cognitive load had no effect on distractibility, which suggests the results from Experiment 2 were caused by periodically responding to the auditory stimuli. These findings have important implications for our understanding of selective attention and shed light on tasks that require the processing of multisensory information.No embargoAcademic Major: Psycholog

No evidence for inhibitory deficits or altered reward processing in ADHD: data from a new integrated incentive delay go/no-go task

Objective: Cognitive and motivational factors differentially affect individuals with mental health problems such as ADHD. Here we introduce a new task to disentangle the relative contribution of inhibitory control and reward anticipation on task performance in children with ADHD and/or autism spectrum disorders (ASD). Method: Typically developing children, children with ADHD, ASD, or both disorders worked during separate sessions for monetary or social rewards in go/no-go tasks with varying inhibitory load levels. Participants also completed a monetary temporal discounting (TD) task. Results: As predicted, task performance was sensitive to both the effects of anticipated reward amount and inhibitory load. Reward amount had different effects depending on inhibitory load level. TD correlated with inhibitory control in the ADHD group. Conclusion: The integration of the monetary incentive delay and go/no-go paradigms was successful. Surprisingly, there was no evidence of inhibitory control deficits or altered reward anticipation in the clinical groups

Shallow grooves in journal improve air bearing performance

Bearing designs, which shape the surface to create artificial fluid-film wedges in the absence of any applied radial load, generate radial restoring forces to keep journals from whirling. Helical- or herringbone-grooved journals or rotors show most promise of stable operation, with no sacrifice in load capacity