Application of UPFC to Improve the LVRT Capability of Wind Turbine Generator

Variable speed wind turbine generators installation has been significantly increased worldwide in the last few years. Voltage sag at the grid side may call for the disconnection of the wind turbine from the grid as under such faults it may not comply with the recent developed grid codes for wind energy conversion systems (WECS). In this paper, a Unified Power Flow Controller (UPFC) is applied to improve the low voltage ride through (LVRT) capability of doubly fed induction generator (DFIG)-based WECS during voltage sag at the grid side. Simulation is carried out using MATLAB/Simulink software. Results show that UPFC can significantly improve the LVRT capability of DFIG-based WECS and hence maintaining wind turbine connection to the grid during certain levels of voltage sag at the grid side

Effect of prenatal exposure to bisphenol a on the vagina of albino rats: immunohistochemical and ultrastructural study

Background: Bisphenol-A (BPA) is an industrial chemical, used to manufacture polycarbonate and numerous plastic articles. It has been found to cause biological effects, mimic that of oestrogen. It belongs to a group of chemicals termed “endocrine disruptors” able to disrupt the chemical messenger system in the body. Aim of the study was to demonstrate the biological effects of BPA on the vagina of female rats, with the prediction of the neoplastic changes in relation to its potential impact. Materials and methods: Sprague-Dawley gravid dams were divided into three groups (10 per group): G1 — control group had an equivalent volume of sesame oil to that taken in the treated groups, G2 — group was administered by gavage 0.1 mg BPA/kg body weight (low-dose group) per day, and G3 — group was administered 50 mg BPA/kg body weight (high-dose group) per day, dissolved in sesame oil. Treatment was carried out on gestation days 10 through 20. The female offsprings of each group were weaned at day 21 and the vagina was dissected when became 3 months old for histological, immunohistochemical analysis (for detection of oestrogen receptors a [ERa], and the proliferation marker Ki-67), and ultrastructural study. Results: The low dose group showed degeneration of the epithelial lining with focal patches of decreased epithelial layers. The high dose group revealed cytoplasmic hydropic degeneration, and the pyknotic nuclei of epithelial cells. Oestrogen receptors demonstrated a significant decrease of positive cells in low dose treated group and this decrease markedly accentuated in the high dose one. Positive nuclei for Ki-67 were markedly increased with increasing doses of BPA. Electron microscopic study revealed cytoplasmic degeneration, vacuolation and mitochondrial degeneration in both treated groups. Conclusions: BPA showed an obvious mix of degenerative and proliferative histological changes and clear damage of the cellular organelles. This stressful condition may predispose to neoplastic changes of the vagina.

Gross alpha and beta surveys of Lake Kainji water

A gross alpha and beta survey of the water of Kainji Lake was conducted using multi-channel analyzer, a proportional counter detector. This was done to estimate the gross radioactivity concentrations due to natural radionuclides in the lake water. Radioactivity, a phenomenon that leads to production of radiations, and radiation is known to trigger or induce cancer. The gross alpha and beta activity concentration analyzed in the water shows that the alpha activity ranges from 1.0 x 105 Bq/cm3 to 0.7Bq/cm3 with an average value indication of 0.0702Bq/cm3, whereas the beta activity concentration indicated BDL for all the sites with exception of upstream 01 location (9~' 51' 485' and 4~'35' 473'E) which has 0.0022Bq/cm3. This could be attributed to the continued flow of the lake water. Although radioactivity measured in lakes is usual higher than that of flowing waters, because a significant part of the radioactive substance brought in by other tributary rivers accumulates in it (Szaho et al.1998). That of Kainji Lake is entirely different

Understanding the Burden of Atopic Dermatitis in Africa and the Middle East

Atopic dermatitis (AD) is a common inflammatory skin disease characterized by intensely pruritic lesions. The prevalence of atopic dermatitis is increasing in developing regions, including Africa and the Middle East. However, these regions are underrepresented in the dermatology literature, and a better understanding of the growing burden of atopic dermatitis in Africa and the Middle East is necessary. Herein, we summarize current knowledge on atopic dermatitis epidemiology, disease burden, and treatment options in Africa and the Middle East, highlighting the unmet needs of patients in these regions. With these needs in mind, we provide clinical recommendations for appropriate management of atopic dermatitis in Africa and the Middle East. Funding: Pfizer Inc. Plain Language Summary: Plain language summary available for this article.Editorial/medical writing support under the guidance of the authors was provided by Madeline L. Pfau, PhD, and Corey Mandel, PhD, at ApotheCom, New York, NY, and San Francisco, CA, USA, and was funded by Pfizer Inc., New York, NY, USA, in accordance with Good Publication Practice (GPP3) guidelines ( Ann Intern Med. 2015;163:461-464).Scopu

Measuring socioeconomic status in multicountry studies: Results from the eight-country MAL-ED study

Background: There is no standardized approach to comparing socioeconomic status (SES) across multiple sites in epidemiological studies. This is particularly problematic when cross-country comparisons are of interest. We sought to develop a simple measure of SES that would perform well across diverse, resource-limited settings. Methods: A cross-sectional study was conducted with 800 children aged 24 to 60 months across eight resource-limited settings. Parents were asked to respond to a household SES questionnaire, and the height of each child was measured. A statistical analysis was done in two phases. First, the best approach for selecting and weighting household assets as a proxy for wealth was identified. We compared four approaches to measuring wealth: maternal education, principal components analysis, Multidimensional Poverty Index, and a novel variable selection approach based on the use of random forests. Second, the selected wealth measure was combined with other relevant variables to form a more complete measure of household SES. We used child height-for-age Z-score (HAZ) as the outcome of interest. Results: Mean age of study children was 41 months, 52% were boys, and 42% were stunted. Using cross-validation, we found that random forests yielded the lowest prediction error when selecting assets as a measure of household wealth. The final SES index included access to improved water and sanitation, eight selected assets, maternal education, and household income (the WAMI index). A 25% difference in the WAMI index was positively associated with a difference of 0.38 standard deviations in HAZ (95% CI 0.22 to 0.55). Conclusions: Statistical learning methods such as random forests provide an alternative to principal components analysis in the development of SES scores. Results from this multicountry study demonstrate the validity of a simplified SES index. With further validation, this simplified index may provide a standard approach for SES adjustment across resource-limited settings.publishedVersio

Predicted modulated differential rates for direct WIMP searches at low energy transfers

The differential event rate for direct detection of dark matter, both the time averaged and the modulated one due to the motion of the Earth, are discussed. The calculations focus on relatively light cold dark matter candidates (WIMP) and low energy transfers. It is shown that for sufficiently light WIMPs the extraction of relatively large nucleon cross sections is possible. Furthermore for some WIMP masses the modulation amplitude may change sign, meaning that, in such a case, the maximum rate may occur six months later than naively expected. This effect can be exploited to yield information about the mass of the dark matter candidate, if and when the observation of the modulation of the event rate is established.Comment: 16 pages, 22 figures; references adde

Progress in interfacial solar steam generation using low-dimensional and biomass-derived materials

The pressing concern of escalating water scarcity has spurred the creation of advanced technologies, such as interfacial solar steam generation (ISSG), to tackle the challenge. ISSG employs solar energy for efficient water desalination and purification. This comprehensive review delves into various aspects of ISSG, primarily focusing on elucidating its mechanisms, optimizing substrate materials, implementing thermal management strategies, and exploring applications. The study dissects the intricate mechanism of ISSG, highlighting photothermal behaviors across different materials, including the significant role of nanoparticles in vapor generation. The impact of substrate composition and shape on solar evaporation efficiency is investigated, with multi-surface evaporators considered for environmental energy harnessing. To enhance performance, thermal management strategies, including innovative water transport paths for improved heat distribution, are assessed. Addressing key challenges like salt accumulation, biofouling, corrosion, and oil fouling, the review offers insights for issue mitigation. Practically, ISSG is spotlighted for its role in seawater desalination, wastewater treatment (e.g., dye and heavy metal removal), oil-water separation, and sterilization, extending its relevance across industries and healthcare. By comprehensively examining ISSG's mechanisms, substrate considerations, thermal strategies, and applications, this review advances its implementation as a transformative solution for global water challenges

Racism, anti-racist practice and social work: articulating the teaching and learning experiences of Black social workers

In the mid 1990s a Black practice teacher programme was established in Manchester and Merseyside with the primary aim to increase the number of Black practice teachers in social work organisations, and in turn provide a supportive and encouraging learning environment for Black student social workers whilst on placement. In the north‐west of England research has been undertaken, to establish the quality of the practice teaching and student learning taking place with Black practice teachers and students. This paper is an exploration of the ideas generated within the placement process that particularly focused on the discourse of racism and ant‐racist practice. Black students and practice teachers explain their understanding of racism and anti‐racist practice within social work. From the research, the paper will critique some of the ideas concerning anti‐racism. In particular, it will question whether anti‐racist social work practice needs to be re‐evaluated in the light of a context with new migrants, asylum seekers and refugees. It will concluded, by arguing that whilst the terms anti‐racism, Black and Minority Ethnic have resonance as a form of political strategic essentialism, it is important to develop more positive representations in the future

Groundwater resources in the Indo-Gangetic Basin : resilience to climate change and abstraction

Groundwater within the Indo‐Gangetic Basin (IGB) alluvial aquifer system forms one of the world’s most important and heavily exploited reservoirs of freshwater. In this study we have examined the groundwater system through the lens of its resilience to change – both from the impact of climate change and increases in abstraction. This has led to the development of a series of new maps for the IGB aquifer, building on existing datasets held in Pakistan, India, Nepal and Bangladesh, a review of approximately 500 reports and papers, and three targeted field studies on under‐researched topics within the region. The major findings of the study are described below. The IGB groundwater system 1. The IGB alluvial aquifer system comprises a large volume of heterogeneous unconsolidated sediment in a complex environmental setting. Annual rainfall varies from 2000mm in the Bengal basin, and the system is dissected by the major river systems of the Indus, Ganges and Brahmaputra. The groundwater system has been modified by the introduction of large scale canal irrigation schemes using water from the Indus and Ganges since the 19th and early 20th centuries. 2. High yielding tubewells can be sustained in most parts of the alluvial aquifer system; permeability is often in the range of 10 – 60 m/d and specific yield (the drainable porosity) varies from 5 – 20%, making it highly productive. 3. High salinity and elevated arsenic concentrations exist in parts of the basin limiting the usefulness of the groundwater resource. Saline water predominates in the Lower Indus, and near to the coast in the Bengal Delta, and is also a major concern in the Middle Ganges and Upper Ganges (covering much of the Punjab Region in Pakistan, southern Punjab, Haryana and parts of Uttar Pradesh in India). Arsenic severely impacts the development of shallow groundwater in the fluvial influenced deltaic area of the Bengal Basin. 4. Recharge to the IGB aquifer system is substantial and dynamic, controlled by monsoonal rainfall, leakage from canals, river infiltration and irrigation returns. Recharge from rainfall can occur even with low annual rainfall (350 mm) and appears to dominate where rainfall is higher (> 750 mm). Canal leakage is also highly significant and constitutes the largest proportion of groundwater recharge in the drier parts of the aquifer, partially mitigating the effects of abstraction on groundwater storage. 5. Deep groundwater (>150 m) in the Bengal basin has strategic value for water supply, health and economic development. Excessive abstraction poses a greater threat to the quality of this deep groundwater than climate change. Heavy pumping may induce the downward migration of arsenic in parts of Bangladesh, and of saline water in coastal regions, but field evidence and modelling both suggest that deep groundwater abstraction for public water supply in southern Bangladesh is in general secure against widespread ingress of arsenic and saline water for at least 100 years

Non-standard interactions using the OPERA experiment

We investigate the implications of non-standard interactions on neutrino oscillations in the OPERA experiment. In particular, we study the non-standard interaction parameter $\epsilon_{\mu\tau}$. We show that the OPERA experiment has a unique opportunity to reduce the allowed region for this parameter compared with other experiments such as the MINOS experiment, mostly due to the higher neutrino energies in the CNGS beam compared to the NuMI beam. We find that OPERA is mainly sensitive to a combination of standard and non-standard parameters and that a resulting anti-resonance effect could suppress the expected number of events. Furthermore, we show that running OPERA for five years each with neutrinos and anti-neutrinos would help in resolving the degeneracy between the standard parameters and $\epsilon_{\mu\tau}$. This scenario is significantly better than the scenario with a simple doubling of the statistics by running with neutrinos for ten years.Comment: 15 pages, 5 figures, REVTeX