Study of photovoltaic (PV) module interconnections failure analysis and reliability

A thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the award of Doctor of Philosophy.Solar Energy is one of the most widely used renewable energy sources, with the solar Photovoltaic (PV) module technologies deployed as one of the primary renewable energy sources to replace fossil fuels. However, the R&D challenge for improving the performance and reliability of PV modules has become an urgent and critical agenda for the energy generation industry sector. The interconnection between the solar PV cells is a very important part of the PV module assembly, and its failure can adversely affect the performance and reliability of the PV module. The interconnection failure has been mostly linked to the crack initiation and propagation in the solder joints used to connect the ribbon interconnection to the cell. This research focuses on the study of the thermal failure of PV module solder joint to determine the optimum ribbon interconnection designs that will give improved thermo-mechanical reliability. It develops a virtual reliability qualification process for the assessment of the life expectancy of PV module interconnections. The FEM simulations in ABAQUS 2019 software are implemented to investigate failure of the solder joints in different ribbon interconnection designs under anticipated life cycle loading conditions and high temperature lamination process. For the first time, the extended finite element method (XFEM) technique is used to determine the crack initiation temperature, crack location, direction and growth rate in solder joint of PV module interconnection under lamination process. Furthermore, the research used the Developed Morrow Energy Density lifetime model to determine the number of cycles to creep-fatigue failure, and then it defined a new generic exponent factor using the Coffin–Manson–Arrhenius model to estimate the lifetime for the designs under different thermal cycling conditions. The research also combines the numerical results of XFEM and creep-fatigue investigation to determine the failure lifetime of PV Module interconnection designs. The results show that the Multi-Busbar interconnection design improves solder joint creep-fatigue life (up to 15%) and consequently provides higher thermo-mechanical reliability for the solar PV modules compared to other studied designs (Conventional and the Light Capturing Ribbon interconnections). The results of this PV module interconnections study can be used for evaluating potential design changes and to facilitate design for reliability validation of different configurations for improving the long-term PV module system reliability.Faculty of Science and Engineering, University of Wolverhampton

Qualitative and Quantitative Study of Quercetin and Glycyrrhizin in In Vitro Culture of Liquorice (Glycyrrhiza glabra L.) and Elicitation with AgNO3

Liquorice (Glycyrrhiza glabra L.) is a plant that has been considered for a long time due to its valuable secondary metabolites. This study was conducted to obtain quercetin and glycyrrhizin under controlled conditions and the use of silver nitrate (AgNO3) as an elicitor to increase their production. For this purpose, the seeds were cultured in MS media containing various concentrations of AgNO3 (0, 2, 4, 8 and 10 mg L-1). Quercetin in the aerial parts extract of three-month seedlings prepared with methanol solvent 95% and acetic acid (9:1), and glycyrrhizin in the root extract of four-month seedlings prepared with ethanolic extract (30%) were evaluated qualitatively and quantitatively using HPLC. The results obtained from three replications showed the presence of quercetin and glycyrrhizin in all samples. The amount of quercetin in all samples treated with AgNO3 was significantly higher than control (P≤0.05) and this increase was higher at concentrations of 8 and 10 mg L-1 in comparison with other concentrations. Glycyrrhizin content increased under the influence of different concentrations of AgNO3 as compared to the control; however, this increase was not significant. Our results clearly showed that this method is a practical method to produce and elicit more these compounds with medicinal value

Comparison of the Precision of Measurements in Three Types of Micropipettes according to NCCLS EP5-A2 and ISO 8655-6

Micropipettes or piston pipettes are used to make most volume measurements in fields such as health, chemistry, biology, pharmacy and genetics. Laboratories must ensure that results obtained using these instruments are reliable; therefore, it is necessary to calibrate micropipettes. Before the start of the calibration process, we must check the precision of measurements. The objective of this work is to compare several methods for calculating the precision of three kinds of micropipettes according to the reference value in ISO 8655-6. The medical tests will not have accurate results, if the volume of the liquid doesn’t transfer precisely by micropipettes. Thus, the physician might potentially face problems in the disease diagnosis and its control. In the NCCLS EP5-A2, there is a method to specify and assess the precision of micropipettes by using CV (Coefficient of Variation). Also there are other methods to estimate and test the CV theory, in the formal statistics texts which could be applied to assess the micropipettes precision. In this research we evaluate the precision of lab micropipettes. Three brands of micropipettes, A, B and C are assigned to measure the distilled water mass by using accurate scale which is accurate up to 10-6 to measure 50-gram weights. The experimental environment is a metrology lab which is approved by Iran Standard and Industrial Researches Organization. A technician sampled at the beginning of the experiment and then after 2 hours, the same technician repeated the sampling. Overall, each micropipette is used to measure 40 times with 10-repeat times for single measurement in 28 work days. Common statistical methods are used to estimate and test the CV. Point estimation of CV for micropipettes A, B and C were 0.50%, 0.64% and 1.56%, respectively. Furthermore, the upper limit of 95% confidence bounds for these three micropipettes using the exact method were 0.53%, 0.69% and 1.65%, respectively. Micropipette A met the ISO 8655-6 standard level, but micropipettes B and C did not. On average, measurement errors in micropipettes B and C were respectively 30% and 3.11 times more than micropipette A. By using the approach of CLS EP5-A2 and confidence interval for CV, precision of the three micropipettes were compared. Only one of them met the ISO 8655-6 standard level, but the others failed

Tecnología de semillas sintéticas para la encapsulación y el recrecimiento de puntas de brotes y embriones somáticos de Espárrago officinalis L

Apical buds obtained from Asparagus plant vitro culture and somatic embryos obtained from stem cultivation, explants in MS medium supplemented with mg¹ᶫ 1, 2, 4-D and mg¹ᶫ 1 and Kinetin have been used in this research to produce artificial seeds. We encapsulated apical buds and somatic embryo using 2% sodium alginate and calcium chloride to prepare the artificial seeds. We placed artificial seeds at room temperature (about 25 ° C), in the cold, the temperature of 4 ° C and -18 ° C for different times (15,30,60,90 days) and evaluated the growing power of these seeds in MS and ½MS mediums for further investigations about the viability of seeds. The highest conversion percentage of seedlings in encapsulated embryos (70.01) was related to seed harvested from embryos treated with BA and the highest conversion percentage of seedlings in apical buds (96.54) was obtained from cultivated untreated seeds in MS medium. Encapsulated arteries and buds maintained germination energy and viability with increasing storage time after 90 days of storage at 4 and 25 ° C despite viability reduction while un-capsulated embryos and buds completely lost viability after 60 days of storage at 4 and 25 ° C and seeds stored at -18 ° C completely lost viability after 15 days of storage. In general, the percentage of seed germination and conversion to seedling is higher in seeds cultivated in MS medium compared to seeds cultivated in ½MS medium.En esta investigación se han utilizado yemas apicales obtenidas de cultivo vitro vegetal de espárragos y embriones somáticos obtenidos del cultivo de tallos, explantes en medio MS suplementado con mg¹ᶫ 1, 2, 4-D y mg¹ᶫ 1 y Kinetin para producir semillas artificiales. Encapsulamos yemas apicales y embriones somáticos utilizando alginato de sodio al 2% y cloruro de calcio para preparar las semillas artificiales. Colocamos semillas artificiales a temperatura ambiente (alrededor de 25 ° C), en el frío, la temperatura de 4 ° C y -18 ° C para diferentes tiempos (15,30,60,90 días) y evaluamos el poder de crecimiento de estas semillas. en medios MS y ½MS para futuras investigaciones sobre la viabilidad de las semillas. El mayor porcentaje de conversión de plántulas en embriones encapsulados (70.01) se relacionó con la semilla recolectada de embriones tratados con BA y el mayor porcentaje de conversión de plántulas en yemas apicales (96.54) se obtuvo de semillas cultivadas sin tratar en medio MS. Las arterias y las yemas encapsuladas mantuvieron la energía de germinación y la viabilidad con un mayor tiempo de almacenamiento después de 90 días de almacenamiento a 4 y 25 ° C a pesar de la reducción de la viabilidad, mientras que los embriones y las yemas no encapsulados perdieron completamente la viabilidad después de 60 días de almacenamiento a 4 y 25 ° C y las semillas almacenado a -18 ° C perdió completamente la viabilidad después de 15 días de almacenamiento. En general, el porcentaje de germinación de semillas y conversión a plántula es mayor en semillas cultivadas en medio MS en comparación con semillas cultivadas en medio ½MS

Tecnología de semillas sintéticas para la encapsulación y el recrecimiento de puntas de brotes y embriones somáticos de Espárrago officinalis L

Apical buds obtained from Asparagus plant vitro culture and somatic embryos obtained from stem cultivation, explants in MS medium supplemented with mg¹ᶫ 1, 2, 4-D and mg¹ᶫ 1 and Kinetin have been used in this research to produce artificial seeds. We encapsulated apical buds and somatic embryo using 2% sodium alginate and calcium chloride to prepare the artificial seeds. We placed artificial seeds at room temperature (about 25 ° C), in the cold, the temperature of 4 ° C and -18 ° C for different times (15,30,60,90 days) and evaluated the growing power of these seeds in MS and ½MS mediums for further investigations about the viability of seeds. The highest conversion percentage of seedlings in encapsulated embryos (70.01) was related to seed harvested from embryos treated with BA and the highest conversion percentage of seedlings in apical buds (96.54) was obtained from cultivated untreated seeds in MS medium. Encapsulated arteries and buds maintained germination energy and viability with increasing storage time after 90 days of storage at 4 and 25 ° C despite viability reduction while un-capsulated embryos and buds completely lost viability after 60 days of storage at 4 and 25 ° C and seeds stored at -18 ° C completely lost viability after 15 days of storage. In general, the percentage of seed germination and conversion to seedling is higher in seeds cultivated in MS medium compared to seeds cultivated in ½MS medium.En esta investigación se han utilizado yemas apicales obtenidas de cultivo vitro vegetal de espárragos y embriones somáticos obtenidos del cultivo de tallos, explantes en medio MS suplementado con mg¹ᶫ 1, 2, 4-D y mg¹ᶫ 1 y Kinetin para producir semillas artificiales. Encapsulamos yemas apicales y embriones somáticos utilizando alginato de sodio al 2% y cloruro de calcio para preparar las semillas artificiales. Colocamos semillas artificiales a temperatura ambiente (alrededor de 25 ° C), en el frío, la temperatura de 4 ° C y -18 ° C para diferentes tiempos (15,30,60,90 días) y evaluamos el poder de crecimiento de estas semillas. en medios MS y ½MS para futuras investigaciones sobre la viabilidad de las semillas. El mayor porcentaje de conversión de plántulas en embriones encapsulados (70.01) se relacionó con la semilla recolectada de embriones tratados con BA y el mayor porcentaje de conversión de plántulas en yemas apicales (96.54) se obtuvo de semillas cultivadas sin tratar en medio MS. Las arterias y las yemas encapsuladas mantuvieron la energía de germinación y la viabilidad con un mayor tiempo de almacenamiento después de 90 días de almacenamiento a 4 y 25 ° C a pesar de la reducción de la viabilidad, mientras que los embriones y las yemas no encapsulados perdieron completamente la viabilidad después de 60 días de almacenamiento a 4 y 25 ° C y las semillas almacenado a -18 ° C perdió completamente la viabilidad después de 15 días de almacenamiento. En general, el porcentaje de germinación de semillas y conversión a plántula es mayor en semillas cultivadas en medio MS en comparación con semillas cultivadas en medio ½MS

Effect of Beloved Person’s Voice on Chest Tube Removal Pain in Patients undergoing Open Heart Surgery: Fuzzy Logistic Regression Model

Chest tube removal pain is one of the important complications after open heart surgery. The removal of a chest tube is a painful and frightening experience and should be managed with as little pain and distress as possible. The aim of this study is to assess the effect of beloved person’s voice on chest tube removal pain in patients undergoing open heart surgery. 128 patients were randomly assigned to two groups: one group listened to beloved person’s voice during the procedure, and the other did not. Since pain was measured by linguistic terms, a fuzzy logistic regression was applied for modeling. After controlling for the potential confounders, based on fuzzy logistic regression, the beloved person’s voice reduced the risk of pain. Therefore, using beloved person’s voice could be effective, inexpensive and safe for distraction and reduction of pain

Autonomic dysfunction and white matter microstructural changes in drug-naïve patients with Parkinson’s disease

Background Autonomic dysfunction (AD) is one of the non-motor features of Parkinson’s disease (PD). Some symptoms tend to occur in the early stages of PD. AD also has a great impact on patient’s quality of life. In this study, we aimed to discover the association between AD (Scales for Outcomes in Parkinson’s disease-Autonomic, SCOPA-AUT) and microstructural changes in white matter tracts in drug-naïve early PD patients to elucidate the central effects of autonomic nervous system impairments. Method In total, this study included 85 subjects with PD recruited from the Parkinson’s Progression Markers Initiative (PPMI) database. Among the 85 PD patients, 38 were in Hoehn & Yahr stage 1 (HY1PD) and 47 were in stage 2 (HY2PD). Diffusion magnetic resonance imaging (DMRI) data were reconstructed in the MNI space using q-space diffeomorphic reconstruction to obtain the spin distribution function. The spin distribution function (SDF) values were used in DMRI connectometry analysis. We investigated through diffusion MRI connectometry the structural correlates of white matter tracts with SCOPA-AUT subscores and total score. Results Connectometry analysis also revealed positive association with white matter density in bilateral corticospinal tract in HY1PD patients and negative association in genu of corpus callosum (CC) and, bilateral cingulum in both groups. In addition, there were associations between gastrointestinal, sexual, thermoregulatory and urinary items and structural brain connectivity in PD. Conclusion Our study reveals positive correlation, suggesting neural compensations in early PD. Cingulum and CC tracts have well-known roles in PD pathology, compatible with our findings that bring new insights to specific areas of AD and its role in central nervous system (CNS) neurodegeneration, paving the way for using prodromal makers in the diagnosis and treatment of PD

Crack initiation and growth in PV module interconnection

As the cost of PV (photovoltaic) solar panels drops, it is widely expected that solar energy will become the cheapest source of electricity in many parts of the world over the next two decades. To ensure that PV solar modules have a long service life and can meet the PV manufacturer's warranty, the PV modules need to have high reliability. Solar PV module manufacturers typically provide two warranties: a performance warranty which guarantees 90% of original power output after 10 years and 80% of original output of at 25 years; and an equipment warranty which guarantees their PV module will have a minimum of 10–12 years operation before failure. A critical part of the solar PV module assembly is the ribbon interconnection between the solar cells (i.e. the solder joint interconnections), and failure of the ribbon interconnection can adversely affect the performance and reliability of whole PV module. Ribbon interconnection failures have been linked to the thermal cracks which are initiated in the solder joint material during the high temperature ribbon interconnection manufacturing process; and then the crack propagation and growth associated with the thermal cycling of the ribbon interconnections under higher than ambient temperature PV module operating conditions. This paper reports on the study of high temperature crack initiation and propagation in different PV Module interconnection configurations by using XFEM in ABAQUS software. It concerns a necessary, urgent and fundamental revision of the manufacturing process that lies at the heart of PV module ribbon interconnection manufacture

Wind flow and its interaction with a mobile solar PV system mounted on a trailer

© 2024 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/su16052038Efficient implementation of clean energy technologies is paramount, with mobile solar PV systems on trailers (MSPTs) emerging as pivotal solutions, particularly in regions with limited power grid access. This endeavour is vital for meeting escalating electricity demands and aligning with the UN Sustainable Development Goal (SDG), aimed at ensuring dependable and sustainable energy provision in developing countries. This study investigates the aerodynamic behaviour of a designed MSPT using numerical simulation and experimental methods, thereby offering optimization potential for MSPT design and enhancing overall performance and reliability. Specifically, the study focuses on the effects of wind velocity and tilt angles on the drag and lift forces, as well as drag and lift coefficients on the panel used in the MSPT system. The overall wind force on the entire MSPT, including nine large solar PV panels, is scrutinised, considering combined wind flow and system geometry effects. The numerical investigations were conducted using ANSYS-Fluent software (version 2022/R2) and experimental testing was performed within the C15-10 Wind Tunnel, utilizing scaled-down models to validate the accuracy of the simulation. The findings from the numerical investigations showed an increased turbulence caused by gaps between panels, resulting in almost 62% higher suction flow velocity and 22% higher suction pressure compared to a single panel. Drag and lift forces on the entire MSPT were approximately 6.7 and 7.8 times greater than those on a single panel with the same 30-degree tilt angle, respectively. The findings revealed that scaling forces on a single panel is insufficient for accurately predicting the aerodynamic forces on the entire MSPT. The insights and the knowledge from this study pave the way for further improvements in mobile solar PV technology.This work was funded by the INNOVATE UK project No: 833831 and partially supported by the ReACTIVE Too project that has received funding from the European Union’s Horizon 2020 Research, Innovation and Staff Exchange Programme under the Marie Skłodowska-Curie Action (Grant Agreement No. 871163).Published versio

Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions