Delamination-and electromigration-related failures in solar panels—a review

The reliability of photovoltaic (PV) modules operating under various weather conditions attracts the manufacturer’s concern since several studies reveal a degradation rate higher than 0.8% per year for the silicon-based technology and reached up to 2.76% per year in a harsh climate. The lifetime of the PV modules is decreased because of numerous degradation modes. Electromigration and delamination are two failure modes that play a significant role in PV modules’ output power losses. The correlations of these two phenomena are not sufficiently explained and understood like other failures such as corrosion and potential-induced degradation. Therefore, in this review, we attempt to elaborate on the correlation and the influence of delamination and electromigration on PV module components such as metallization and organic materials to ensure the reliability of the PV modules. Moreover, the effects, causes, and the sites that tend to face these failures, particularly the silicon solar cells, are explained in detail. Elsewhere, the factors of aging vary as the temperature and humidity change from one country to another. Hence, accelerated tests and the standards used to perform the aging test for PV modules have been covered in this review

Mortality in patients treated for tuberculous pericarditis in sub-Saharan Africa.

Tuberculous pericarditis is one of the most severe forms of extrapulmonary tuberculosis, causing death or disability in a substantial proportion of affected people.1,2 In Africa, the incidence of tuberculous pericarditis is rising as a result of the HIV epidemic.3 The effect of HIV infection on survival in patients with tuberculous pericarditis is unknown.2,4 Whereas some investigators have suggested that HIV-infected patients with tuberculous pericarditis have a similar outcome to non-infected cases,5 others have shown that there may be an increase in mortality in HIV associated with tuberculous pericarditis.2,6,7 We established a prospective observational study, the Investigation of the Management of Pericarditis in Africa (IMPI Africa) registry, to obtain current information on the diagnosis, management and outcome of patients with presumed tuberculous pericarditis living in sub-Saharan Africa, where the burden of HIV infection is the greatest in the world.4,8-10 In this paper, we report the mortality rate and its predictors during the 6 months of antituberculosis treatment among patients enrolled in the regis

Clinical characteristics and initial management of patients with tuberculous pericarditis in the HIV era: the Investigation of the Management of Pericarditis in Africa (IMPI Africa) registry

BACKGROUND: The incidence of tuberculous pericarditis has increased in Africa as a result of the human immunodeficiency virus (HIV) epidemic. However, the effect of HIV co-infection on clinical features and prognosis in tuberculous pericarditis is not well characterised. We have used baseline data of the Investigation of the Management of Pericarditis in Africa (IMPI Africa) registry to assess the impact of HIV co-infection on clinical presentation, diagnostic evaluation, and treatment of patients with suspected tuberculous pericarditis in sub-Saharan Africa. METHODS: Consecutive adult patients in 15 hospitals in three countries in sub-Saharan Africa were recruited on commencement of treatment for tuberculous pericarditis, following informed consent. We recorded demographic, clinical, diagnostic and therapeutic information at baseline, and have used the chi-square test and analysis of variance to assess probabilities of significant differences (in these variables) between groups defined by HIV status. RESULTS: A total of 185 patients were enrolled from 01 March 2004 to 31 October 2004, 147 (79.5%) of whom had effusive, 28 (15.1%) effusive-constrictive, and 10 (5.4%) constrictive or acute dry pericarditis. Seventy-four (40%) had clinical features of HIV infection. Patients with clinical HIV disease were more likely to present with dyspnoea (odds ratio [OR] 3.2, 95% confidence interval [CI] 1.4 to 7.4, P = 0.005) and electrocardiographic features of myopericarditis (OR 2.8, 95% CI 1.1 to 6.9, P = 0.03). In addition to electrocardiographic features of myopericarditis, a positive HIV serological status was associated with greater cardiomegaly (OR 3.89, 95% CI 1.34 to 11.32, P = 0.01) and haemodynamic instability (OR 9.68, 95% CI 2.09 to 44.80, P = 0.0008). However, stage of pericardial disease at diagnosis and use of diagnostic tests were not related to clinical HIV status. Similar results were obtained for serological HIV status. Most patients were treated on clinical grounds, with microbiological evidence of tuberculosis obtained in only 13 (7.0%) patients. Adjunctive corticosteroids were used in 109 (58.9%) patients, with patients having clinical HIV disease less likely to be put on them (OR 0.37, 95% CI 0.20 to 0.68). Seven patients were on antiretroviral drugs. CONCLUSION: Patients with suspected tuberculous pericarditis and HIV infection in Africa have greater evidence of myopericarditis, dyspnoea, and haemodynamic instability. These findings, if confirmed in other studies, may suggest more intensive management of the cardiac disease is warranted in patients with HIV-associated pericardial disease

Mortality in patients treated for tuberculous pericarditis in sub-Saharan Africa

Objective: To determine the mortality rate and its predictors in patients with a presumptive diagnosis of tuberculous pericarditis in sub-Saharan Africa. Design: Between 1 March 2004 and 31 October 2004, we enrolled 185 consecutive patients with presumed tuberculous pericarditis from 15 referral hospitals in Cameroon, Nigeria, and South Africa, and observed them during the 6-month course of antituberculosis treatment for the major outcome of mortality. This was an observational study, with the diagnosis and management of each patient left at the discretion of the attending physician. Using Cox regression, we have assessed the effect of clinical and therapeutic characteristics (recorded at baseline) on mortality during follow-up. Results: We obtained the vital status of 174 (94%) patients (median age 33; range 14-87 years). The overall mortality rate was 26%. Mortality was higher in patients who had clinical features of HIV infection than in those who did not (40% versus 17%, P=0.001). Independent predictors of death during follow-up were: (1) a proven non-tuberculosis final diagnosis (hazard ratio [HR] 5.35, 95% confidence interval 1.76 to 16.25), (2) the presence of clinical signs of HIV infection (HR 2.28, 1.14-4.56), (3) co-existent pulmonary tuberculosis (HR 2.33, 1.20-4.54), and (4) older age (HR 1.02, 1.01-1.05). There was also a trend towards an increase in death rate in patients with haemodynamic instability (HR 1.80, 0.90-3.58) and a decrease in those who underwent pericardiocentesis (HR 0.34, 0.10-1.19). Conclusion: A presumptive diagnosis of tuberculous pericarditis is associated with a high mortality in sub-Saharan Africans. Attention to rapid aetiological diagnosis of pericardial effusion and treatment of concomitant HIV infection may reduce the high mortality associated with the disease

Artificial ripening on banana (Musa Spp.) samples: Analyzing ripening agents and change in nutritional parameters

In recent years, the use of artificial fruit ripening agents has become prevalent mostly due to the commercial purposes. Different ripening agents are reported to be used to initiate the ripening process in fruits during off-seasons. However, the effects of these agents on the nutritional values of fruits are yet to be fully understood. The purpose of this study is to measure, analyze and compare the nutritional value of naturally and artificially ripened fruits. Bari-1 hybrid banana (Musa Spp.; local name: Sagor Kola) was chosen to carry out the experimental study. Ripe samples were collected directly from orchards or local markets. Additionally, unripe green samples were collected and artificially ripened in the laboratory using artificial ripening agents: ethephon, calcium carbide, ethylene glycol and fume from the kerosene stove. Different nutrition parameters, such as moisture content, total titratable acidity, vitamin C and sugar content were assessed for these banana samples. The assessed parameters of naturally and artificially ripened fruits were compared and analyzed to identify the change in nutritional values and determine the health hazards associated with them. The chemical compositions of artificial ripening agents were also investigated and possible health risks related to the impurities of ripening agents were assessed. Therefore, the key objective of this study is to address the changes in nutritional values and health risks associated with the artificial ripening which will be helpful for the consumers, nutritionists, physicians and other shareholders

Postdeposition Annealing Effect on Cu2ZnSnS4 Thin Films Grown at Different Substrate Temperature

Cu2ZnSnS4 (CZTS) thin films were deposited on top of Molybdenum (Mo) coated soda lime glass (SLG) substrates using a single target rf magnetron sputtering technique. The sputtering parameters such as base pressure, working pressure, rf power, argon (Ar) gas flow rate, and deposition time were kept consistent throughout the experiment. The effect of different substrate temperatures, for example, room temperature (RT), 300°C, 350°C, 370°C, 400°C, and 450°C, was analyzed by studying their structural, electrical, and optical properties. As-sputtered films were then annealed at 460°C. X-ray diffraction (XRD) measurement revealed the structure to be kesterite with peak of (112) plane in both annealed and as-sputtered CZTS thin films. The crystallinity of the films improved with the increasing substrate temperature until 370°C. Secondary phases of MoS2, CuxMoSx, CuxSnSx, CuxS, and Cu6MoSnS8 (hemusite) were also observed in the annealed CZTS films. Scanning electron microscopy (SEM) shows crystallite size of deposited CZTS thin film to be proportionally related to deposition temperature. The highest surface roughness of 67.318 nm is observed by atomic force microscopy (AFM). The conductivity type of the films was found to be p-type by Hall effect measurement system

Delamination-and Electromigration-Related Failures in Solar Panels—A Review

The reliability of photovoltaic (PV) modules operating under various weather conditions attracts the manufacturer’s concern since several studies reveal a degradation rate higher than 0.8% per year for the silicon-based technology and reached up to 2.76% per year in a harsh climate. The lifetime of the PV modules is decreased because of numerous degradation modes. Electromigration and delamination are two failure modes that play a significant role in PV modules’ output power losses. The correlations of these two phenomena are not sufficiently explained and understood like other failures such as corrosion and potential-induced degradation. Therefore, in this review, we attempt to elaborate on the correlation and the influence of delamination and electromigration on PV module components such as metallization and organic materials to ensure the reliability of the PV modules. Moreover, the effects, causes, and the sites that tend to face these failures, particularly the silicon solar cells, are explained in detail. Elsewhere, the factors of aging vary as the temperature and humidity change from one country to another. Hence, accelerated tests and the standards used to perform the aging test for PV modules have been covered in this review

The relationship between medical comorbidities and health-related quality of life among adults with type 2 diabetes: The experience of different hospitals in southern Bangladesh.

ObjectiveHealth-related quality of life (HRQoL) is a critical determinant to assess the severity of chronic diseases like diabetes mellitus. It has a close association with complications, comorbidities, and medical aid. This study aimed to estimate the prevalence of medical comorbidities and determine the relationship between comorbidities and HRQoL among type 2 diabetic patients of southern Bangladesh.MethodThis study was a cross-sectional study conducted through face to face interviews using a pre-tested structured questionnaire and by reviewing patient's health records with prior written consent. The study was conducted on 2,136 patients with type 2 diabetes attending five hospitals of Chattogram, Bangladesh, during the tenure of November 2018 to July 2019. Quality of life was measured using the widely-used index of EQ-5D that considers 243 different health states and uses a scale in which 0 indicates a health state equivalent to death and 1 indicates perfect health status. The five dimensions of the quality index included mobility, self-care, usual activities, pain or discomfort, and anxiety or depression.ResultsPatients with three comorbidities and with four or more comorbidities had a higher probability of reporting "extreme problem" or "some problem" in all five dimensions of the EQ-5D index compared with those without comorbidity (Odds ratio: mobility, 3.99 [2.72-5.87], 6.22 [3.80-10.19]; usual activity, 2.67 [1.76-4.06], 5.43 [3.28-8.98]; self-care, 2.60 [1.65-4.10], 3.95 [2.33-6.69]; pain or discomfort, 2.22 [1.48-3.33], 3.44 [1.83-6.45]; anxiety or depression, 1.75 [1.07-2.88], 2.45 [1.19-5.04]). The number of comorbidities had a negative impact on quality of life.ConclusionPrevalent comorbidities were found to be the significant underlying cause of declined HRQoL. To raise diabetes awareness and for better disease management, the exposition of comorbidities in regards to HRQoL of people with diabetes should be considered for type 2 diabetes management schemas

Fabrication of black silicon via metal-assisted chemical etching—a review

The metal-assisted chemical etching (MACE) technique is commonly employed for texturing the wafer surfaces when fabricating black silicon (BSi) solar cells and is considered to be a potential technique to improve the efficiency of traditional Si-based solar cells. This article aims to review the MACE technique along with its mechanism for Ag-, Cu- and Ni-assisted etching. Primarily, several essential aspects of the fabrication of BSi are discussed, including chemical reaction, etching direction, mass transfer, and the overall etching process of the MACE method. Thereafter, three metal catalysts (Ag, Cu, and Ni) are critically analyzed to identify their roles in producing cost-effective and sustainable BSi solar cells with higher quality and efficiency. The conducted study revealed that Ag-etched BSi wafers are more suitable for the growth of higher quality and efficiency Si solar cells compared to Cu- and Ni-etched BSi wafers. However, both Cu and Ni seem to be more cost-effective and more appropriate for the mass production of BSi solar cells than Ag-etched wafers. Meanwhile, the Ni-assisted chemical etching process takes a longer time than Cu but the Nietched BSi solar cells possess enhanced light absorption capacity and lower activity in terms of the dissolution and oxidation process than Cu-etched BSi solar cells