Improved optical and electrical properties for heterojunction solar cell using Al2O3/ITO double-layer anti-reflective coating
بهبود خواص نوری و الکتریکی برای سلول های خورشیدی ناهمگون با استفاده از پوشش ضد انعکاس دو لایه Al2O3/ITO-2021
Silicon heterojunction solar cells have been gaining remarkable attention in the photovoltaic industry in recent years owing to their low temperature coefficient and high efficiency. This study aimed to maximize the short circuit current density (Jsc), which is directly correlated with the absorbance of the solar cells. An advanced ray tracking model and hall effect measurement was used to improve the optical properties of Al2O3/ITO as a double layered anti-reflection coating (DLARC) on the solar cell. RF/DC power sputtering system was used to deposit ITO layer, while atomic layer deposition was used to deposit Al2O3 on ITO to create a DLARC. An average decrease in reflection from 9.33% to 4.74% and enhancement in EQE from 76.89% to 84.34% were observed for the DLARC in the wavelength spectrum at 300–1100 nm. It also exhibited a higher Jsc value of 41.13 mA/cm2 and maximum conversion efficiency of 21.6%. The findings of both simulation and experiments showed that the Al2O3/ITO DLARC has better anti-reflection properties than a single-layer ITO coating.
Keywords: Silicon heterojunction solar cell | Double layered anti-reflection coating | Optical Properties | Electrical Properties
Framing accounting for goodwill: Intractable controversies between users and standard setters
فریم کردن حسابداری برای حسن نیت: اختلافات قابل انعطاف بین کاربران و برنامه های استاندارد-2021
How to account for goodwill arising from business combinations has proven to be one the most controversial topics for the standardisation, preparation, and audit of financial reports. Given its contested nature, and recent debates about improper goodwill accounting by failing companies, standard setters are currently reconsidering existing recognition, measurement, and disclosure requirements. In this study, we explore the views of a relatively neglected group of stakeholders in the financial reporting policy-making arena – financial statement users. We draw on empirical evidence from interviews with financial analysts and from responses by analysts to IASB and EFRAG consultations. We mobilise framing theory as used in public policy studies to analyse how users make sense of goodwill accounting information as compared to standard setters. Our key finding is the plurality of colliding frames between users and standard setters that remain intractable. Our analysis reveals that users’ interest in management’s accountability on acquisi- tions cannot fit easily into the financial reporting frame. Not only are claims by standard setters about the value relevance of goodwill impairments found not to be experienced in practice, but also we discover that users question the benefits of standard setters working in this area, while they take recourse to ‘street numbers’ for their analysis. We interpret the intractability we discover as putting into question public policy claims that accounting policies are developed with a commitment to serve the public interest.
keywords: IFRS | حسن نیت | آنالیز مالی | کادر بندی | IFRS | Goodwill | Financial analysis | Framing
Correction of left ventricular doppler echocardiographic measurements for physiological variances using a novel optimized multivariable allometric model in healthy chinese han adults
اصلاح اندازه گیری های اکوکاردیوگرافی داپلر بطن چپ برای واریانس های فیزیولوژیکی با استفاده از یک مدل آلوومتری چند متغیره بهینه سازی شده در افراد سالم هان چینی-2021
Most left ventricular (LV) Doppler measurements vary significantly with age and gender, making it necessary to correct them for physiological variances. We aimed to verify the hypothesis that different Doppler measurements correlate nonlinearly with different biometric variables raised to different scaling factors and exponents. In this work, a total of 23 LV Doppler parameters were measured in 1224 healthy Chinese adults. An optimized multivariable allometric model (OMAM) and scaling equations were developed in 70% of the subjects (group A), and the reliability of the model and equations was verified using the remaining 30% of the subjects (group B) as well as 183 overweight subjects (group C). The single-variable isometric model (SVIM) with body surface area (BSA) as a scaling variable was used for comparison. Before correction, all 23 LV Doppler parameters correlated significantly with one or more of the biometric variables. In group B, gender differences were found in 47.8% (11/23) of the parameters and were eliminated in 81.8% (9/11) of the parameters after correction with OMAM. The successful correction rate with OMAM was 100% (23/23) in group B and 82.6% (19/23) in group C. New reference values for corrected Doppler measurements independent of biometric variables were established. The SVIM with BSA successfully corrected none of the 23 parameters. In conclusion, different LV Doppler parameters allometrically correlated with one or more of the biometric variables. The novel OMAM developed in this study successfully corrected the effects of the physiological variances of most biometric variables on Doppler measurements in healthy and overweight subjects, and was found to be far superior to the SVIM. However, whether the OMAM equations can be applied to other ethnicities, obese subjects, and pathological conditions requires further investigation.
Effect of CNT additives on the electrical properties of derived nanocomposites (experimentally and numerical investigation)
تأثیر افزودنیهای CNT بر خواص الکتریکی نانوکامپوزیتهای مشتقشده (بررسی تجربی و عددی)-2021
In this work, two simulations models have been developed to study the electrical percolation and the electrical conductivity of epoxy-based nanocomposite containing Multi-walled Carbon Nanotubes. The models are based on resistor-model and finite element analysis. The former was evaluated using MATLAB code and the finite element analysis using DIGIMAT software. The maximum tunneling distance and its influence on the percolation probability and final electrical conductivity were studied. Electrical measurements on the samples were conducted for numerical validation. The experimental data showed a percolation achievement around 2 wt%, which was confirmed in the numerical simulations. This study provides evidence of the effectiveness of the resistor model and finite element method approach to predict the electrical conductivity of nanocomposites.
Keywords: Polymer-matrix composites (PMCs) | Nanocomposites | Carbon nanotube | Electrical properties | Computational modelling
Lossless fuzzy extractor enabled secure authentication using low entropy noisy sources
استخراج کننده فازی بدون تلفات ، احراز هویت ایمن را با استفاده از منابع پر سر و صدا کم آنتروپی فعال کرد-2021
Fuzzy extractor provides a way for key generation from biometrics and other noisy data. It has been widely applied in biometric authentication systems that provides natural and passwordless user authentication. In general, given a random sample, a fuzzy extractor extracts a nearly uniform random string, and subsequently regenerates the string using a different yet similar noisy sample. However, due to error tolerance between the two samples, fuzzy extractor imposes high information loss (entropy) and thus, it only works for an input with high enough entropy. In this work, we propose a lossless fuzzy extractor for a large family of sources. The proposed lossless fuzzy extractor can be adopted for a wider range of random sources to extract an arbitrary number of nearly uniform random strings. Besides, we formally defined a new entropy measurement, named as equal error entropy, to measure the entropy loss in reproducing a bounded number of random strings. When the number of random strings is large enough, the equal error entropy is minimized and necessary for performance evaluation on the authentication using the extracted random strings.
Keywords: Authentication | Biometric | Fuzzy extractor | Secure sketch
Income inequality and ethnic cleavages in Malaysia: Evidence from distributional national accounts (19842014)
نابرابری درآمد و شکاف های قومی در مالزی: شواهدی از حساب های توزیع ملی (19842014)-2021
In this paper, by combining information obtained from national accounts, household surveys, and fiscal data, we document the evolution of income inequality in Malaysia, not only at the national level (for the period of 1984–2014) but also by ethnic group (for the period of 2002–2014). To our knowledge this is the first attempt to produce inequality measurements of Malaysia, which are fully consistent with the national accounts. Our research shows that despite Malaysia’s exceptional economic growth rate, its growth has been inclusive. For the period of 2002–2014, the real income growth for the bottom 50 % is the highest (5.2 %), followed by the middle 40 % (4.1 %), the top 10 % (2.7 %) and then the top 1 % (1.6 %). However, while average growth rates are positive across all ethnic groups (Bumiputera 4.9 %, Indians 4.8 %, and Chinese 2.7 %), the highest growth of real income per adult accrued to the Bumiputera in the top 1 % (at 8.3 %), which sharply contrasts the much lower growth rate of the Indians (at 3.4 %) and negative income growth rates of the Chinese (at 0.6 %). Despite the negative growth rate, the Chinese still account for the lion’s share in the top 1 %. In 2014, 60 % of the adults in the top 1 % income group are Chinese, while 33 % Bumiputera, and 6 % Indians. We conclude that in this period, Malaysia’s growth features an inclusive redistribution between income classes, but with a twist between racial groups.
keywords: اقدامات مثبت | حساب های ملی توزیع | شکاف های قومی | نابرابری درآمد | مالزی | Afﬁrmative actions | Distributional national accounts | Ethnic cleavages | Income inequality | Malaysia
Layer number dependent optical and electrical properties of CVD grown two-dimensional anisotropic WS2
خواص نوری و الکتریکی وابسته به تعداد لایه WS2 ناهمسانگرد دوبعدی رشد CVD-2021
Engineering 2D transition metal dichalcogenides with precise control over layer number enable tuning of exciting optical and electrical properties at the nanoscale level. We report controlled one-step chemical vapour deposition growth of WS2 monolayer, bilayer, and trilayer for large scale manufacturing and demonstrate layer dependent changes in their work function, photoluminescence, and electrical conductivity. Raman, photoluminescence, and fluorescence imaging revealed that the base WS2 monolayer contains alternating triangular domains with different emission properties. It is observed that bilayer and trilayer grow selectively on less luminescent facet leading to fan-like morphology for second and third layers. We have systematically demonstrated that desired growth and areal coverage of bilayer and trilayer can be achieved by controlling WO3 precursor content. Kelvin probe force microscopic studies suggest a higher work function of thicker layers as compared to the monolayer. It was found that work function increases by 0.04 eV when thickness increases from monolayer to bilayer. FET device measurement on mono and bilayer shows n-type characteristics and two-fold higher photo-current in monolayer in comparison to the bilayer. The studied thickness dependence of the work function of WS2 is vital to the fabrication of metal contacts for WS2 based electronic and optoelectronic devices.
Keywords: CVD growth | 2D materials | PL segmentation | Optoelectronics | Transition metal dichalcogenides | KPFM
Urban landfills investigation for leachate assessment using electrical resistivity imaging in Johor, Malaysia
بررسی محل های دفن زباله شهری برای ارزیابی شیرابه با استفاده از تصویربرداری مقاومت الکتریکی در جوهور، مالزی-2021
The use of the electrical resistivity imaging (ERI) approach has expanded dramatically in engineering applications over the years due to the efficiency of the technique in terms of time, expense, and data coverage. The assessment was carried out using ERI to assess the landfill leachate’s pollution level at Simpang Renggam, Johor, Malaysia. The ERI survey was carried out in the research region, utilizing the ABEM Terrameter LS 2 equipment using the Schlumberger electrode configuration. Besides, seven (7) parameters of leachate characterization such as Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD5), Suspended Solid (SS), Power of Hydrogen (pH), Ammonia Hydrogen (NH3-N), Turbidity and Biodegradability Ratio (BOD5/COD) were also performed to identify and evaluate the current leachate condition of the landfill. Furthermore, the study, which involves the measurement of the apparent resistivity of the subsurface materials were able to determine the existence of chemical pollutants in the soil at 1.5 m to 4.0 m depth, with special reference to the chemically apparent resistivity linked with the low resistivity anomalies of 1 – 10 Ωm. Based on the investigations conducted, the physiochemical and microbial analysis of the Simpang Renggam leachate site was found to be 1633 mg/L (Chemical Oxygen Demand), 137.41 mg/L (Biological Oxygen Demand), 359.8 mg/L (Suspended Solid), 7.61 (Power of Hydrogen), 385.29 (Ammonia Hydrogen), 117.65 (Turbidity) and 0.07 (Biodegradability Ratio) which shows that all of the parameter’s value exceeded the value as stated in the local standard which is Environmental Quality Act (1974) except for the pH value which is within the range value as stated in the standard. The leachate from dumps was thought to arise due to system failures in accepting and managing trash, which was exacerbated by the recent high rains. In hindsight, the ERI result was practical for identifying leachate and, therefore, can benefit the authorities in immediate action to halt the extensive water disturbance at the research region.
Keywords: Landfill Leachate | Electrical Resistivity Imaging | Leachate Characterization | Contaminants
Linking standard Economic Account for Forestry and ecosystem accounting: Total forest incomes and environmental assets in publicly-owned conifer farms in Andalusia-Spain
پیوند حساب استاندارد اقتصادی برای حسابداری جنگلداری و اکوسیستم: کل درآمد جنگل ها و دارایی های محیطی در مزارع عمومی متعلق به مالکیت در اندلس اسپانیا-2021
A major problem faced by government as trustee of society charged with conserving the nation’s forest envi- ronmental asset is that the standard Economic Account for Forestry (EAF) fails to measure the contribution of nature to total forest incomes and environmental assets. In the context of this government mission, the debate arises with regard to how to uncover the contribution of nature to the total forest incomes enjoyed by people through a refined accounting framework which extends the EAF. The latter is applied by the statistics office to estimate the values added of timber, firewood, cork, resin, industrial nut and other non-woody final products of the forest at national/sub-national scale. Bearing in mind this narrow scope of the EAF, this research proposes the application of the experimental Agroforestry Accounting System (AAS), which extends the forest incomes and environmental asset estimates by applying simulated exchange values stated/revealed by consumers for non- market public goods and services. We apply the EAF and AAS frameworks to 12 large publicly-owned pro- tected conifer forest farms which are not available for sale on the competitive land market and which cover an area of 47,262 ha in Andalusia-Spain. In this conifer farm case study, the EAF considers the economic activities of timber, firewood, aromatic plants and residential service. The AAS adds to the EAF activities those of grazing, conservation forestry, hunting, livestock, agricultural crops, livestock-keeper private amenity, fire services, free access recreation, mushrooms, carbon, landscape conservation, threatened wild biodiversity and water supply runoff stored lower down the watershed in public reservoirs. The objectives of this conifer farm case study are, first, to compare the final products and incomes estimated by applying the EAF and AAS frameworks and, second, to measure the sensitivity of conifer farm environmental assets to changes in land ownership rights and dis- counting rates in accordance with the AAS results. The conifer farm results show total income measured by the AAS is 38 times higher than the EAF net value added (NVA) for the 2010 period. The AAS economic activities of forestry conservation, fire services and landscape conservation activities generate 71% of the conifer farm labour compensation. The AAS opening environmental asset measured at the assumed competitive real baseline dis- counting rate of 3% is 6371.6 €/ha, which is 3.7 times lower than it would be if the conifer farm was available for sale on the competitive land market. The change in the baseline discounting rate chosen, from 3% to 1.5%, would lead to an increase of 116% in the value of the opening environmental asset. The above results reveal the inconsistent EAF measurement of total conifer farm incomes. The sensitivity analysis underlines the important effects on the environmental asset arising from changes in land ownership rights and discounting rates.
keywords: حساب اقتصادی برای جنگلداری | سیستم حساب های ملی | سیستم حسابداری جنگلداری | خدمات محیط زیستی | درآمد زیست محیطی | Economic account for forestry | System of national accounts | Agroforestry accounting system | Ecosystem services | Environmental income
Interval growth across gestation in pregnancies with fetal gastroschisis
رشد فاصله در حاملگی در حاملگی با گاستروشسیس جنین-2021
BACKGROUND: Gastroschisis is often complicated by fetal growth restriction, preterm delivery, and prolonged neonatal hospitalization. Prenatal management and delivery decisions are often based on estimated fetal weight and interval growth; however, appropriate interval growth from week to week across gestation for these fetuses is poorly understood.
OBJECTIVE: This study aimed to determine the median increase in overall estimated fetal weight and individual biometric measurements across each week of gestation in pregnancies with fetal gastroschisis and to assess whether lower in utero fetal weight gain is predictive of postnatal growth or adverse neonatal outcomes.
STUDY DESIGN: This was a retrospective cohort study of pregnancies with gastroschisis evaluated at 5 institutions of the University of California Fetal-Maternal Consortium from December 2014 to December 2019. The inclusion criteria were prenatally diagnosed gastroschisis with at least 1 ultrasound performed at a University of California Fetal-Maternal Consortium institution. Estimated fetal weight and individual biometric measurements were recorded for each ultrasound performed at a University of California Fetal-Maternal Consortium institution from the time of gastroschisis diagnosis to delivery. Median estimated fetal weight and biometric measurements were calculated for each gestational age in 1-week increments. Neonatal outcomes collected were birthweight, length of stay, complications of gastroschisis (bowel atresia, bowel stricture, ischemic bowel before closure, or severe pulmonary hypoplasia), and growth failure at discharge.
RESULTS: We identified 95 pregnancies with fetal gastroschisis who, in aggregate, had 360 growth ultrasounds at a University of California FetalMaternal Consortium institution. The median interval growth was 130 g/wk. The median estimated fetal weight and abdominal circumference in fetal gastroschisis cases were approximately the tenth percentile on the Hadlock growth curve across gestation. Moreover, the median biparietal diameter, head circumference, and femur length measurements remained below the 50th percentile on the Hadlock growth curve across gestation. The median birthweight for neonates with less than the median weekly prenatal weight gain was less than for those with greater than the median weekly prenatal weight gain (2185 g vs 2780 g; P<.01). There was no difference in prenatal weight gain trajectory when comparing neonates who had or did not have bowel complications of gastroschisis.
CONCLUSION: In this multicenter cohort of pregnancies with fetal gastroschisis, the median interval growth was 130 g/wk, and overall, in utero growth closely followed the tenth percentile on the Hadlock curve. Poor prenatal growth in cases of fetal gastroschisis correlates with lower neonatal weights but did not predict a more complicated course. Key words: abdominal wall defect | biometric parameters | fetal anomaly | fetal growth restriction | nomograms | postnatal growth