PVT Performance Research Articles

B - 143 A Comparison of Structured Inventory of Malingered Symptomology (SIMS) Performance to Multiple Validity Measures in a Criminal Forensic Sample

Abstract Objective We compared valid or invalid SIMS performance to other performance and symptom validity measures. Methods Data from 119 forensic neuropsychological evaluations [competency (n = 106), forensic (n = 5), insanity (n = 5), commitment review (n = 2), and danger (n = 1)] were analyzed. Three chi-squares tests compared group membership (valid/invalid) for SIMS total score, affective (AF) subscore, or low intelligence (LI) subscore to a separate valid or invalid group membership based on MMPI-2-RF (VRIN-r and TRIN-r), WAIS-IV Reliable Digit Span, and WMT (IR, DR, and CONS) validity cutoff scores (74% failed >2 measures). Results Sample was predominately male (91.6%) and Caucasian (53.8%). Mean age was 35.1 years; mean education was 11.36 years. For SIMS total, 36% failed the SIMS but passed all other validity measures [χ 2(1) = 21.668; p < 0.001; V = 0.427] for a 64% concordance rate for overall valid performance. Individuals with valid scores on the SIMS AF subscale were likely (66%) to have valid performance on all other validity measures [χ 2(1) = 12.418; p < 0.001; V = 0.323]. Individuals with valid scores on the SIMS LI subscale were essentially at chance (52%) to have performed validly overall [χ 2(1) = 9.406; p = 0.002; V = 0.0.281]. Conclusions In this forensic criminal sample, a third of individuals failed the SIMS total score and AF subscale while having credible performance otherwise. Approximately half failed the LI subscale while passing other validity measures. Results suggest that SIMS performance is not strongly related to SVT measures that focuses on response consistency or PVT performance; there is still significant classification overlap. However, high base rate of PVT/SVT failure in this sample may limit generalizability.

Simulation of lower Cambrian oil and gas generation and phase evolution process in ZH1 of Tazhong area

The Lower Cambrian petroleum system in the Tarim Basin has undergone multiple periods of tectonic movements, leading to successive hydrocarbon expulsion events and adjustments. The complex process of hydrocarbon accumulation occurred under deep burial conditions, persisting at depths of nearly 6,000 m over an extended period. This has resulted in the current occurrence of various phases including light oil, condensate, and gas in the deep-ultradeep strata of the Tarim Basin. The intricacies of formation of hydrocarbon accumulations and phase evolution have posed challenges to understanding the accumulation mechanisms and enrichment patterns of the Cambrian in the Tarim Basin, consequently lowering the success rate of oil and gas exploration. Such characteristics of multi-stage accumulation and adjustment are prevalent in deep hydrocarbon systems. Therefore, based on data from Well ZH1 in the Tazhong Uplift, combined with basin simulation, Compositional kinetics model, and PVT performance simulation, this study investigates the hydrocarbon generation and phase evolution processes in the deep hydrocarbon systems of the Tazhong Uplift. The results indicate that Well ZH1 entered the hydrocarbon generation peak during the Late Ordovician, followed by secondary cracking as the predominant hydrocarbon evolution process. Hydrocarbon fluids within the Lower Cambrian reservoir transitioned into the condensate phase towards the end of the Cambrian, with increasing depth resulting in higher gas-oil ratios and a decreasing trend in viscosity and density.

Optimization of the PVT performance with various orientations of jets and MFFNN-RSA prediction model for smart buildings

The combined thermal and photovoltaic technology in PV/T systems is considered as a greatly promising technology for smart buildings. Thus, investigations for enhancing the PV/T performance are still proceeding. This research presents an investigation for novel configurations of cooling jets for the PVT system. The linear and circular distribution for the inlet jets considering regular and irregular positioning for all the jets as new cooling configurations are implemented. Moreover, the proposed geometrical configurations are optemized regarding the performance to identify the most suitable configuration that achieves the optimum efficiency and temperature. Furthermore, a novel hybrid ANN model is presented for predicting the performance of the PVT systems. This model combines the multi-feedforward neural network (MFFNN) with an optimization technique called reptile search algorithm (RSA). The proposed model can process the studied parameters to predict the PVT performance parameters (top surface temperature, temperature un-uniformity, outlet temperature, and efficiencies). The proposed MFFNN-RSA model minimized the mean square error to less than 0.4857×10-3. The maximum temperature decrease achieved by the presented configuration reached 60.62K compared to the uncooled case, while the minimum temperature un-uniformity reached 1K and 6K for 400 and 1000 W/m2, respectively. The increase of the ambient temperature found to decrease the temperature un-uniformity in all the cases. The irregular jet with the linear distribution was found to achieve the optimum performance of the overall, thermal, and electrical efficiencies of 63.5%, 49.6%, and 14.25%, respectively. Furthermore, the electricity production cost was reduced by 11.6%, and the yearly CO2 emissions were reduced by 215.3 kg/m2 compared to the normal PV system. The proposed irregular-line distribution of the jets is found to be the best configuration regarding the temperature of the PV model and the overall efficiency considering the pumping losses.

An effective parametric sensitivity analysis to improve electrical and thermal energy/exergy efficiency of PVT system using nanofluid

A 3D steady-state model of a photovoltaic/Thermal system with nanofluid is studied to investigate the electrical and thermal performance of PVT by utilizing a combination of statistical modeling and numerical simulation. The 3D CAD (Computer Aided Design) modeling of the photovoltaic thermal (PV/T) is performed using Ansys Space Claim. The current study is based on using a 2-way coupling FSI approach for modeling nanofluid-based PVT systems. Five output responses electrical power, thermal power, electrical exergy, thermal exergy, and entropy generation are chosen against four input parameters, solar radiation (G_sun), ambient temperature (Tamb), mass flow rate (ṁ), and nanoparticles concentration % (φ) to analyze system performance. A statistical prediction model is developed using response surface methodology (RSM) that starts from the design of experiment (DOE). The predicted outcomes obtained from the statistical model and the numerical simulation of the heat transfer model exhibit the existence of good fitness. Furthermore, optimization is performed using RSM for various optimization objectives to suggest the ideal design parameter values for optimal system performance. Sensitivity analysis illustrates that a rise in ambient temperature causes a drop in electrical power production and leads to an increase in thermal power. However, the increase in solar radiation boosts electrical power and causes a drop in thermal exergy, entropy generation increases with an increase in solar irradiation. Similarly, an increase in mass flow rate leads to an increase in thermal power. Multi-objective optimization with the highest composite desirability values depicts the influence of input design parameters and has a favorable effect on the objective of concurrently maximizing electrical and thermal power.

Moderate pre-sleep alcohol has a negative impact on next-day PVT performance

Moderate pre-sleep alcohol has a negative impact on next-day PVT performance

Efficiency improvement of ternary nanofluid within a solar photovoltaic unit combined with thermoelectric considering environmental analysis

Impacts of environmental parameters and dust deposition on the efficiency of solar panel have been scrutinized in this article. To gain thermal output, trapezoidal cooling channel has been attached in the bottom of the panel incorporating ternary nanofluid. To produce working fluid, water has been mixed with Fe3O4TiO2GO nanoparticles. Also, the arrangement of fins has been considered to grow the cooling rate of the silicon layer. The existence of a thermoelectric layer above the cooling channel leads to higher electrical output. Efficacy of ambient temperature (Ta), speed of wind (Vwind) and inlet temperature (Tin) and velocity (Vin) of ternary nanofluid on performance of PVT has been assessed. As Tin increases, electrical efficiency declines about 3.63%. Increase of ambient temperature makes thermal performance enhance about 33.46%. The PVT efficiency decreases about 13.14% and 16.6% with augment of wind speed and dust deposition. CO2 mitigation has been uced about 15.49% in presence of dust while it increases about 17.38% with growth of ambient temperature.

0075 Melatonin impairs morning cognition in healthy young adults without any benefit to sleep

Abstract Introduction Exogenous melatonin has been shown to improve sleep in individuals with sleep disorders, such as insomnia and delayed sleep phase disorder. However, research on the effect of exogenous melatonin on sleep in healthy young adults is limited. Additionally, there is some evidence that melatonin can negatively affect cognitive processes, such as long-term memory, working memory, and attention. Therefore, we assessed the effect of melatonin supplementation on nocturnal sleep and morning cognition in healthy undergraduates. Methods In the evening, participants (N = 120) completed three cognitive tasks: the Psychomotor Vigilance Task (PVT; a measure of attention), UNRAVEL (a measure of procedural placekeeping), and the Paired Associates Learning (PAL) test (a measure of long-term memory). We then asked participants to take a pill under double-blind conditions that contained either melatonin or placebo. Afterwards, participants received an 8-hour sleep opportunity monitored with polysomnography (PSG). One hour after waking, participants completed PAL, UNRAVEL, and PVT again. Results We compared morning cognitive performance across the melatonin and placebo conditions, with evening performance as a covariate. Interestingly, melatonin participants had more placekeeping errors than placebo. However, melatonin did not affect PVT or PAL performance. We found no significant differences between the melatonin and sleep groups on any of our sleep measures. Conclusion The results suggest that negative performance effects of exogenous melatonin may outweigh any benefits for healthy young adults, particularly when cognitive performance is measured shortly after the sleep opportunity. Our results also suggest that sleep factors captured by PSG may not accurately predict next-day cognitive performance, and that researchers should consider additional factors, such as melatonin concentration, when assessing the relationship between sleep and performance. Support (if any) This work was funded by the Office of Naval Research (N00014-20-1-2739).

0166 Effects of Evening Pre-Sleep Alcohol on Next-Day Psychomotor Vigilance (PVT) Performance

Abstract Introduction Few reports have examined how pre-sleep alcohol affects performance on the next day given adequate sleep opportunity on a preferred schedule. Our goal is to identify whether alcohol intake targeting .08g% 1 hr before sleep of ~8 h will affect PVT performance on subsequent days, with the hypothesis that morning performance will be negatively affected. Methods 25 adults (13F; age range 22-57 y) completed the full study, including at-home sleep on a fixed schedule of 8-9 hr and two 3-night in-lab PSG sessions spaced ≥3 days apart. Sessions were counterbalanced for alcoholic or nonalcoholic control beverage administered in 3 drinks over 45 minutes ending 1 hr before bedtime. Alcohol was targeted to .08g%. The 10-min PVT (Ambulatory Monitoring, Inc.) was given each night (PM-Lab) 1.5 hr before drinking and in the morning after a light breakfast (AM-Lab) 50 min after waking. PVT was performed at home/work twice each day within 1.5-h windows starting 3h after waking (AM-Home) and 7.5h after waking (PM-Home). Two reaction time (RT) variables were assessed: RRT (1/RT), FRT (10% fastest RT). Linear mixed effects models were used to account for nesting of assessments within alcohol/control condition and days. Results RRTs showed slowed RT (meanRT±SE) following alcohol: AM-Lab F=7.234, p=.008, alcohol RT=246±9.6 msec, control RT=234±9.6 msec; AM-Home F=17.936, p<.001, alcohol RT=254±9.5 msec, control RT=242±9.6 msec; but not PM-Home or PM-Lab tests. FRT slowed for AM-Lab F=9.391, p=.003, alcohol FRT=195±4.3 msec, control FRT=201±4.3 msec; AM-Home F=17.251, p=.001, alcohol FRT= 202±4.4 msec, control FRT=194±4.4 msec; PM-Home F=3.379, p=.068 (trend), alcohol FR=200±4.8 msec, control FRT=196±4.8 msec, but not for PM-Lab PVTs. PM-Home FRT also had a significant day order effect: F=3.087, p=.0496, Day 1 FRT=197±5.0 msec, Day 2 FRT=202±5.0 msec, Day 3 FRT=195±5.0 msec. Conclusion We found statistically significant slowing of psychomotor vigilance RT on days after pre-sleep alcohol lasting up to 3-4.5h after waking in the morning (with a trend up to 7.5-9h post waking). PVT lapses (not shown) were similarly affected by alcohol. Thus, even with sufficient sleep opportunity, RT is impaired following 3 consecutive nights of alcohol drinking. Support (if any) R01AA025593

0226 Effect of Wake Extension and Short Recovery Sleep on Objective Vigilance and Subjective Sleepiness in Young Adolescents

Abstract Introduction Adolescents routinely experience insufficient sleep. Compared to adults, less is known regarding how wake extension and recovery sleep impact objective and subjective indexes of vigilance in youth. Here we explore these questions using acute wake extension. Methods Twenty-two 10–13-year-old children (12.03±1.14 years, 12F) completed a week of actigraphy-monitored at-home sleep stabilization (9.5h TIB). Participants then slept in the laboratory with polysomnography for a baseline (BSL) opportunity of 9.5h (21:00-06:30) and returned the subsequent evening for wake extension (WE) to 02:30 and a 4h recovery sleep opportunity (02:30-06:30). Participants completed performance testing batteries including a 5-minute tablet-based visual adaptation of the psychomotor vigilance task (PVT; BrainBaseline) and introspective ratings at 20:00 and 07:30, as well as at three additional times during WE: 22:00, 00:00, and 01:30. The current analyses focused on PVT reciprocal reaction time (RRT: 1/RT) and the Stanford Sleepiness Scale (SSS) ratings. Results One-way ANOVA across WE (20:00, 22:00, 00:00, 01:30) showed a main effect of time for slower reaction times as participants remained awake (m±sd [1/s] 20:00: 2.01±0.32; 22:00: 1.84±0.33; 00:00: 1.79±0.29; 01:30: 1.71±0.34; F(3,63)=13.78, p<.05, ηp2= .40). After recovery sleep, RRTs at 07:30 (1.69±0.31) were slower than those at 07:30 after baseline sleep (1.95±0.36) (t(21)=5.46, p<.001) and did not differ from 01:30 during WE (t(21)=0.64, p=0.53), indicating persistent impairment after recovery sleep. A main effect of time during WE was also seen for the SSS (20:00: 1.77±0.69; 22:00: 3.36±1.71; 00:00: 4.14±1.21; 01:30: 5.68±1.25; F(3,63)=56.80, p<.001, ηp2= .73). Morning SSS scores were higher (sleepier) on WE (2.24±1.30) than BSL (1.71±0.90) (t(20)=2.45, p=.024). However, unlike RRTs, morning SSS scores were also significantly lower (less sleepy) at 07:30 following recovery sleep compared to 01:30 during WE (t(21)=9.80, p<.001). Conclusion Vigilance performance and sleepiness after 13.5 until 19 h awake worsened and PVT performance did not improve after 4h recovery sleep; however, perceived sleepiness after 4h recovery sleep decreased. This incongruent performance and perception confirms the vulnerability of youth to even partial sleep loss. Our next analyses will consider inattention phenotypes and recovery sleep physiology as potential moderators of these effects. Support (if any) K01MH109854, P20GM139743

Comprehensive Analysis of MMPI-2-RF Symptom Validity Scales and Performance Validity Test Relationships in a Diverse Mixed Neuropsychiatric Setting.

The utility of symptom (SVT) and performance (PVT) validity tests has been independently established in neuropsychological evaluations, yet research on the relationship between these two types of validity indices is limited to circumscribed populations and measures. This study examined the relationship between SVTs on the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) and PVTs in a mixed neuropsychiatric setting. This cross-sectional study included data from 181 diagnostically and demographically diverse patients with neuropsychiatric conditions referred for outpatient clinical neuropsychological evaluation at an academic medical center. All patients were administered a uniform neuropsychological battery, including the MMPI-2-RF and five PVTs (i.e., Dot Counting Test; Medical Symptom Validity Test; Reliable Digit Span; Test of Memory Malingering-Trial 1; Word Choice Test). Nonsignificant associations emerged between SVT and PVT performance. Although the Response Bias Scale was most predictive of PVT performance, MMPI-2-RF SVTs generally had low classification accuracy for predicting PVT performance. Neuropsychological test performance was related to MMPI-2-RF SVT status only when overreporting elevations were at extreme scores. The current study further supports that SVTs and PVTs measure unique and dissociable constructs among diverse patients with neuropsychiatric conditions, consistent with literature from other clinical contexts. Therefore, objective evidence of symptom overreporting on MMPI-2-RF SVTs cannot be interpreted as definitively indicating invalid performance on tests of neurocognitive abilities. As such, clinicians should include both SVTs and PVTs as part of a comprehensive neuropsychological evaluation as they provide unique information regarding performance and symptom validity.

Brighter Time: A Smartphone App Recording Cognitive Task Performance and Illuminance in Everyday Life.

Light is an influential regulator of behavioural and physiological state in mammals. Features of cognitive performance such as memory, vigilance and alertness can be altered by bright light exposure under laboratory and field conditions. However, the importance of light as a regulator of performance in everyday life is hard to assess and has so far remained largely unclear. We set out to address this uncertainty by developing a tool to capture measures of cognitive performance and light exposure, at scale, and during everyday life. To this end, we generated an app (Brighter Time) which incorporated a psychomotor vigilance (PVT), an N-back and a visual search task with questionnaire-based assessments of demographic characteristics, general health, chronotype and sleep. The app also measured illuminance during task completion using the smartphone’s intrinsic light meter. We undertook a pilot feasibility study of Brighter Time based on 91-week-long acquisition phases within a convenience sample (recruited by local advertisements and word of mouth) running Brighter Time on their own smartphones over two study phases in winter and summer. Study compliance was suitable (median = 20/21 requested task completions per subject). Statistically significant associations were observed between subjective sleepiness and performance in all tasks. Significant daily variations in PVT and visual search performance were also observed. Higher illuminance was associated with reduced reaction time and lower inverse efficiency score in the visual search. Brighter Time thus represents a viable option for large-scale collection of cognitive task data in everyday life, and is able to reveal associations between task performance and sleepiness, time of day and current illuminance. Brighter Time’s utility could be extended to exploring associations with longer-term patterns of light exposure and/or other light metrics by integrating with wearable light meters.

0183 Daily sleep predicts adolescents’ next-day psychomotor vigilance, sleepiness, and fatigue: Ecological momentary assessment across 28 days of school and vacation

Abstract Introduction Few studies have examined the associations between daily sleep and daytime functioning in adolescents during naturalistically-occurring constrained (school term) and unconstrained (vacation) sleep opportunities. Methods Adolescents (n = 205; 54.1% females, age M ± SD = 16.9 ± 0.87 years) completed daily measures of sleep and daytime functioning over 28 continuous days (2-week school, and the subsequent 2-week vacation). Total sleep time (TST) and sleep efficiency (SE) were measured using actigraphy and sleep diary. Participants self-reported sleepiness and fatigue every morning and afternoon, and completed the brief, 3.2-minute psychomotor vigilance task (PVT; Joggle Research) on an iPad every afternoon. Using cross-lagged multilevel models, daily TST and SE were examined as predictors of next-day sleepiness, fatigue, and PVT performance. The associations did not differ between school and vacation. The non-significant interaction terms were dropped, and school/vacation status was maintained as a covariate. Previous-day outcome, day of the week, study day, school/vacation and sociodemographics were adjusted. Between-person associations (differences between individuals) and within-person associations (daily deviations from individual’s own mean capturing whether nights with longer- or better-than-average TST or SE respectively, relative to the individual’s average TST/SE, predict next-day outcomes) were tested simultaneously. Results Adolescents performed better on the PVT (faster reaction time and fewer lapses) following nights with longer-than-average TST (actigraphy and diary, p-values ≤ .044). Longer-than-average TST (actigraphy and diary) and higher diary SE also predicted lower self-reported sleepiness the next day (morning and afternoon, p-values ≤ .002). Similarly, longer-than-average TST and higher-than-average SE predicted lower self-reported fatigue the next day (morning and afternoon, all p-values ≤ .032). Compared to the vacation, school term was associated with higher self-reported fatigue in the morning and afternoon (p-values ≤ .014), but not higher sleepiness or poorer PVT performance. Conclusion Fluctuations in daily sleep were associated with adolescents’ next-day functioning. Importantly, longer- and better-than-average sleep consistently predicted better daytime functioning the next day. Findings were consistent across objective sustained attention and self-reported sleepiness and fatigue, highlighting the short-term effects of sleep restriction on adolescents’ daytime functioning. Protecting adolescents’ sleep duration and promoting good quality sleep on a daily basis could support optimal daytime functioning. Support (If Any) Dr Shen was supported by the Monash International Postgraduate Research Scholarship and Monash Graduate Scholarship.

Thermo-electro-hydraulic analysis of jet impingement bifacial photovoltaic thermal (JIBPVT) solar air collector

The effects of impinging air jet on the thermo-electro-hydraulic performance of a bifacial PVT with different packing factors are entirely unclear. Here, we have proposed a dual-functional jet plate reflectors are introduced to induce jet air cooling and increase the light absorption at the rear part of the bifacial PV module. The effects of jet plate reflectors with different configurations on the system's performance are investigated and studied. The simulation results were verified and validated with the experimental findings. Increasing the distance between jet holes reduces the interference and enhances the heat transfer, which led to higher friction and greater pumping power. Net energy gain is the key to calculate hydraulic efficiency, by subtracting the pumping power from the energy output. Therefore, the system's best performance can be explained by the lowest Re to generate max efficiencies. Jet impingement bifacial photovoltaic thermal (JIBPVT) with 36 jet-holes has the greatest jet spacing between the jet holes and optimum performance. The maximum thermal energy gain and electrical energy produced were achieved at lower critical values of Re, which are 9929 and 5667, respectively. JIBPVT has the optimum thermal, electro, and thermo-electro-hydraulic efficiencies, with 57.3%, 10.36%, and 83.93%, respectively.

Performance Assessment of an Air-Type BIPVT Collector with Perforated Baffles through Indoor and Outdoor Experiments

The performance of air-type PVT and BIPVT collectors has been extensively studied. As a system that generates heat and power, PVT collector testing has some particularities especially when using air as a heat recovery fluid and a building-integrated design (BIPVT). The electrical and thermal experimental performance of such collectors are currently being evaluated using in-house methods or PV and/or solar thermal collector standards. The use of a wide range of methods, testing conditions and experimental setups makes it difficult not only to compare the performance of different designs, but also to have confidence in the results obtained. This study evaluates the performance of an air-type BIPVT collector with in-channel perforated baffle plates for heat transfer enhancement designed for a building-integrated façade. As part of a joint research project between Korea and Canada, the proposed collector’s performance was evaluated through indoor (Canada) and outdoor experiments (Korea). Limited comparison of the results obtained with the two testing methods could be performed due to differences in environmental testing conditions, BIPVT collector area and experimental setup. Nevertheless, the limited measurement points under comparable testing conditions indicate that the results from the indoor and outdoor experiments have a similar trend. A comparison between the studied collector having a full PV absorber and a BIPVT collector with a hybrid PV/solar thermal collector absorber using a similar indoor experimental setup and testing conditions was performed. It showed that under still air conditions, for an irradiance level of approximately 820 W/m2 and with a low flow rate, the BIPVT collector with a hybrid PV/solar thermal absorber has a thermal and electrical efficiency of 25.1% and 5.9%, respectively. Under similar conditions, the BIPVT collector with a full PV absorber has a thermal efficiency of 23.9% and an electrical efficiency of 13.5%. At higher flowrates, both units have similar thermal efficiencies, however, the BIPVT collector with a PV absorber remains with an electrical efficiency that is more than double that of the unit with a hybrid PV/solar thermal absorber.

Self-reported disability-seeking predicts PVT failure in veterans undergoing clinical neuropsychological evaluation

Objective: This study examined disability-related factors as predictors of PVT performance in Veterans who underwent neuropsychological evaluation for clinical purposes, not for determination of disability benefits. Method: Participants were 1,438 Veterans who were seen for clinical evaluation in a VA Medical Center’s Neuropsychology Clinic. All were administered the TOMM, MSVT, or both. Predictors of PVT performance included (1) whether Veterans were receiving VA disability benefits (“service connection”) for psychiatric or neurological conditions at the time of evaluation, and (2) whether Veterans reported on clinical interview that they were in the process of applying for disability benefits. Data were analyzed using binary logistic regression, with PVT performance as the dependent variable in separate analyses for the TOMM and MSVT. Results: Veterans who were already receiving VA disability benefits for psychiatric or neurological conditions were significantly more likely to fail both the TOMM and the MSVT, compared to Veterans who were not receiving benefits for such conditions. Independently of receiving such benefits, Veterans who reported that they were applying for disability benefits were significantly more likely to fail the TOMM and MSVT than were Veterans who denied applying for benefits at the time of evaluation. Conclusions: These findings demonstrate that simply being in the process of applying for disability benefits increases the likelihood of noncredible performance. The presence of external incentives can predict the validity of neuropsychological performance even in clinical, non-forensic settings.

Numerical analysis of a small sized water based solar photovoltaic-thermal collector

ABSTRACT Large-sized collectors suffer from heat loss from its top due to large aperture plane area. In this work, numerical investigation is performed on a small-sized solar-based photovoltaic thermal water collector using a channel type absorber to analyze its performance under different operating and ambient conditions. A 3D numerical model is developed using COMSOL multi-physics software and the thermal and hydraulic performances of the PV-T collector are carried out. The influence of Reynolds number on the Nusselt number is enumerated for a given operating temperature range and solar radiation level. The variations of PV cell temperature, channel water temperature, thermal and electrical efficiency, exergetic efficiency are studied under different mass flow rates, fluid inlet temperatures, and solar radiations, which majorly control the PV-T performance. It has been observed that with increase of Reynolds number heat transfer rate also increases, and as rate of flow increases from 0.004 kg/s to 0.08 kg/s, the electrical and thermal efficiencies also increase and achieve a maximum 89.96% and 11.47%, respectively. Moreover, uniform temperature distribution has been observed for varying mass flow rates under constant inlet temperature and solar radiation. In addition, a maximum total exergy efficiency of 14.68% is achieved at a mass flow rate of 0.02 kg/s, inlet temperature of 32°C and solar radiation of 900 W/m2. On the basis of the present investigation, a small-sized PV-T collector is recommended for future use as an efficient collector that can provide hot water and also electricity for small-scale domestic or industrial applications.

Are there differences in performance validity test scores between African American and White American neuropsychology clinic patients?

ABSTRACT Objective The purpose of the present study was to compare performance on a wide range of PVTs in a neuropsychology clinic sample of African Americans and White Americans to determine if there are differences in mean scores or cut-off failure rates between the two groups, and to identify factors that may account for false positive PVT results in African American patients. Method African American and White American non-compensation-seeking neuropsychology clinic patients were compared on a wide range of standalone and embedded PVTs: Dot Counting Test, b Test, Warrington Recognition Memory Test, Rey 15-item plus recognition, Rey Word Recognition Test, Digit Span (ACSS, RDS, 3-digit time, 4-digit time), WAIS-III Picture Completion (Most discrepant index), WAIS-III Digit Symbol/Coding (recognition equation), Rey Auditory Verbal Learning Test, Rey Complex figure, WMS-III Logical Memory, Comalli Stroop Test, Trails A, and Wisconsin Card Sorting Test. Results When groups were equated for age and education, African Americans obtained mean performances significantly worse than White Americans on only four of 25 PVT scores across the 14 different measures (Stroop Word Reading and Color Naming, Trails A, Digit Span 3-digit time); however, FSIQ was also significantly higher in White American patients. When subjects with borderline IQ (FSIQ = 70 to 79) were excluded (resulting in 74 White Americans and 25 African Americans), groups no longer differed in IQ and only continued to differ on a single PVT cutoff (Trails A). Further, specificity rates in African Americans were comparable to those of White Americans with the exception of the b Test, the Dot Counting Test, and Stroop B. Conclusions PVT performance generally does not differ as a function of Black versus White race once the impact of intellectual level is controlled, and most PVT cutoffs appear appropriate for use in African Americans of low average IQ or higher.

A 0.6 V 4 GS/s −56.4 dB THD Voltage-to-Time Converter in 28 nm CMOS

A 0.6 V low-voltage voltage-to-time converter (VTC) has been presented in this work for the emerging energy-efficient time-domain circuits and systems. The proposed VTC supports a rail-to-rail input by leveraging shrink sampling with two cascaded voltage sampling and charge sharing switches, breaking the tradeoff between linearity and input range of the traditional VTC and enabling low voltage operation. The charging current source is adjustable to calibrate the VTC gain variation. In addition, a 4-bit tunable delay buffer is inserted at the output stage to calibrate the VTC time offset, enhancing the PVT performance. By resizing the push-pull inverters’ PMOS/NMOS size ratio in the output buffer chain, the jitter contribution from buffers has been reduced. It also recovers the signal’s pulse width consumed during the voltage-time conversion, facilitating the time signal processing following VTC. Designed and fabricated in 28 nm CMOS, the prototype VTC occupies a 0.0012 mm² active area. Measurement results show that the VTC can run up to 4 GHz at a 0.6 V power supply, achieving -56.4 dB total harmonic distortion (THD) with Nyquist input and consuming 2.1 mW.

Photovoltaic / thermal systems and its importance in domestic use

Hybrid photovoltaic thermal solar system becomes one of the potential to play a significant role in the renewable energy sector. The validation of the photovoltaic/ thermal solar system is not valid in Egypt with proven efficiency of both electrical and thermal system. This paper presents a Comparison between Thermal and PVT performance values for the same area with number of 18 units PVT and 14 units’ thermal units and other parameters to be discussed during the compression in domestic application, see the parameters and boundaries of selected system, and evaluate the performance of each system.

A-212 The Relationships between PAI over-reporting SVTs and PVTs in a Military Sample

Abstract Objective Recent research has worked to explore the relationships between symptom and performance validity testing. The current study sought to examine the association between PAI over-reporting SVTs and well validated stand-alone and embedded PVTs. Methods Retrospective review of 468 active duty Army cases referred for outpatient neuropsychological testing at a Military Health Center. Each subject was administered the PAI, MSVT, NV-MSVT, and RBANS Effort Index. Groups were defined in two ways, as valid (0 PVT failures) or invalid (1 or more PVT failures) and based on the number of failed PVTs (0, 1, 2, and 3). Results Partial results are summarized here for the valid/invalid analysis. The PAI Negative Impression Management (NIM), Multi-Feigning Index (MFI), and Malingering Index (MAL) differed significantly as a function of PVT performance (p < .05). Differences on Rogers Discriminant Function were not significant. AUC for NIM, MAL, and MFI were .69, .66, and .54 (respectively). AUC for RDF was unacceptable at .49. At a T-score of 64 the NIM scale had specificity of .91, sensitivity of .32 and at a T-score of 59 the MAL had specificity of .91 and sensitivity of .14. Conclusions There appears an association between PVTs and PAI over-reporting scales, such that elevations on the NIM, MAL, and MFI scales are related to PVT failure. However, the sensitives of these scales are limited in predicting PVT failure. To this end, the current data are in line with previous studies that indicate the need to administer both performance and symptom validity scales.