Mechanical integrity of photovoltaic panels under hailstorms: Mono vs. poly-crystalline comparison.

The performance of Photovoltaic (PV) modules heavily relies on their structural strength, manufacturing methods, and materials. Damage induced during their lifecycle leads to degradation, reduced power generation and efficiency. Mechanical stresses, originating from manufacturing, transportation, and operational phases impose significant loads on PV modules. These in-service loads encompass various environmental forces such as wind, snow, dust, hail, rain, and heat. In-service loads encompass static and dynamic forces such as wind, snow, dust, hail, rain, and heat. Among these factors, the mechanical loads from hail impacts play a crucial role in PV module performance and require a comprehensive investigation. This research focuses on evaluating the impact of hail loads on different PV modules, following international standards like ASTM 1038-10 and IEC-61215-2. The developed simulator effectively assesses the reliability of PV modules. The number of busbars within a PV module was identified as a key factor influencing the module's resilience to hail impacts. Notably, mono-crystalline PV modules exhibited better resistance to hail loads compared to their poly-crystalline counterparts. The PV modules experience micro-cracking due to hail impacts, leading to an efficiency reduction of 4.15% in mono-crystalline modules and 12.59% in poly-crystalline modules. Similarly, the generated power output decreased by 3.3% and 12.5%, respectively, in these module types.

Lineage replacement and evolution captured by 3 years of the United Kingdom Coronavirus (COVID-19) Infection Survey.

The Office for National Statistics Coronavirus (COVID-19) Infection Survey (ONS-CIS) is the largest surveillance study of SARS-CoV-2 positivity in the community, and collected data on the United Kingdom (UK) epidemic from April 2020 until March 2023 before being paused. Here, we report on the epidemiological and evolutionary dynamics of SARS-CoV-2 determined by analysing the sequenced samples collected by the ONS-CIS during this period. We observed a series of sweeps or partial sweeps, with each sweeping lineage having a distinct growth advantage compared to their predecessors, although this was also accompanied by a gradual fall in average viral burdens from June 2021 to March 2023. The sweeps also generated an alternating pattern in which most samples had either S-gene target failure (SGTF) or non-SGTF over time. Evolution was characterized by steadily increasing divergence and diversity within lineages, but with step increases in divergence associated with each sweeping major lineage. This led to a faster overall rate of evolution when measured at the between-lineage level compared to within lineages, and fluctuating levels of diversity. These observations highlight the value of viral sequencing integrated into community surveillance studies to monitor the viral epidemiology and evolution of SARS-CoV-2, and potentially other pathogens.

Neuropathy following intramuscular injections: a clinical and neurophysiological study from a tertiary care centre in Pakistan.

OBJECTIVE: To assess the clinical and neurophysiological profile of peripheral nerve injuries in patients following intramuscular injections. METHODS: The descriptive, cross-sectional study was conducted at the Department of Neurology, Mayo Hospital, Lahore, Pakistan, from July 2019 to January 2021, and comprised adult patients of either gender with isolated peripheral nerve injuries following intramuscular injections. Nerve conduction studies were performed for each patient. Data was analysed using SPSS 26. RESULTS: Of the 99 patients, 59(59.6%) were males and 40(40.4%) were females. The mean age was 26.7+/-18.1 years, 34(34.3%) patients were under weight and 78(78.8%) were either illiterate or had low literacy level. Radial nerve was involved in 56(56.6%) cases, followed by sciatic in 39(39.4%) and axillary nerve 4(4.04%). Overall, 14(14.14%) injection had been administered by doctors, while the other 85(85.85%) were given by paramadics. Marked reduction in compound muscle action potential 72(72.7%) and sensory nerve action potential 82(82.8%) was noted, while re-innervation was seen in 78(78.7%). CONCLUSIONS: Intramuscular nerve injuries can be greatly minimised by spreading awareness regarding safe injection techniques and strict implementation of standard operating procedures in hospitals and clinics.

Prediction of the Ultimate Strength of Notched and Unnotched IM7/977-3 Laminated Composites Using a Micromechanics Approach.

This paper proposes a multi-scale analysis technique based on the micromechanics of failure (MMF) to predict and investigate the damage progression and ultimate strength at failure of laminated composites. A lamina's representative volume element (RVE) is developed to predict and calculate constituent stresses. Damages that occurred in the constituents are calculated using separate failure criteria for both fiber and matrix. Subsequently, the volume-based damage homogenization technique is utilized to prevent the localization of damage throughout the total matrix zone. The proposed multiscale analysis procedure is then used to investigate the notched and unnotched behavior of three multi-directional composite layups, [30, 60, 90, -60, 30]2S, [0, 45, 90, -45]2S, and [60, 0, -60]3S, subjected to static tension and compression loading. The specimen is fabricated from unidirectionally reinforced composite (IM7/977-3). The prediction of ultimate strength at failure and equivalent stiffness are then benchmarked against the experimental test data. The comparative analysis with various failure models is also carried out to validate the proposed model. MMF demonstrated the capability to correctly predict the ultimate strength at failure for a range of multidirectional composites laminates under tensile and compressive load. The numerically predicted findings revealed a good agreement with the experimental test data. Out of the three investigated composite layups, the simulated results for the quasi-isotropic [0, 45, 90, -45]2S layup agreed extremely well with the experimental results with all the percentage errors within 10% of the measured failure loads.

Structural Imaging Characteristic, Clinical Features and Risk Factors of Cerebral Venous Sinus Thrombosis: A Prospective Cross-Sectional Analysis from a Tertiary Care Hospital in Pakistan.

Cerebral venous sinus thrombosis (CVST) is a rare cause of stroke that accounts for 0.5-1.0% of all strokes. Clinical presentation, predisposing factors, neuroimaging findings, and outcomes of CVST are extremely diverse, which causes a high index of suspicion in diagnosis. Therefore, early diagnosis of CVST is crucial for prompt treatment to prevent morbidity and mortality. OBJECTIVE: The purpose of this prospective study is aimed at assessing the clinical characteristics, potential risk factors, and neuro-radiological features along with the topography of venous sinus involved in CVST patients in a tertiary care hospital, Lahore, Pakistan. MATERIAL AND METHODS: Consecutive patients enrolled in this study had a computed tomography (CT) scan, magnetic resonance imaging (MRI), and magnetic resonance venography (MRV) along with a clinical presentation to confirm the diagnosis of CVST. Categorical data were presented as percentages. Continuous variable and categorical data were compared (parenchymal lesions vs. non-parenchymal lesions) using the Student's t-test and Chi-square test, respectively. RESULTS: A total of 3261 patients with stroke were presented during the study period. Out of all patients, 53 confirmed patients with CVST (1.6%) were recruited; the predominant population was female (84.91%), having a male to female ratio of 1:4. Mean age of the cohort was 28.39 ± 7.19 years. Most frequent symptoms observed were headache (92.45%) followed by vomiting (75.47%), seizures (62.26%), papilledema (54.72%), visual impairment (41.51%), and altered consciousness disturbance (52.83%). The presumed risk factors associated with CVST were puerperium (52.83%), use of oral contraceptives (13.21%), antiphospholipid syndrome (7.55%), elevated serum levels of protein C and S (5.66%), and CNS infection (3.77%). On cranial CT scans, 50 patients (94.33%) showed abnormalities while 32 patients exhibited various parenchymal lesions. Seizures were more frequent in CVST patients with parenchymal lesions compared with subjects lacking parenchymal lesions. Seventy-two sinuses, either single or in combination, were involved in CVST patients, being more common in patients with parenchymal lesions than those without parenchymal lesions. The most frequent locations of CVST were the superior sagittal and transverse sinus. CONCLUSION: In short, non-contrast CT brain may be used as a first line investigation in suspected cases of CVST. Our study also demonstrates some regional differences in the clinical features, risk factors, and neuroimaging details of CVST as described by some other studies. Therefore, care must be taken while diagnosing and predicting the outcome of the CVST.

Sensory symptoms on admission as a predictor of respiratory insufficiency in patients of Guillain-Barre Syndrome (GBS).

OBJECTIVE: To assess sensory symptoms on presentation as a predictor of respiratory insufficiency in patients of Guillain-Barre Syndrome. METHODS: The descriptive cross-sectional study was conducted from November 2018 to March 2019 at the Neurology Department of King Edward Medical University, Lahore, Pakistan, and comprised patients aged 18-60 years suffering from Guillain-Barre Syndrome as per Brighton criteria. All patients were monitored for respiratory insufficiency by single breath count and arterial blood gases. Data was analysed using SPSS 22. Results: Of the 87 patients, 61(70.1%) were male and 26(29.9%) were female. The overall mean age was 37.51±15.36 years. Sensory symptoms were noted in 27(31%) patients, and respiratory distress in 17(19.5%). Of those who had sensory symptoms, 10(37%) also had sensory symptoms. CONCLUSIONS: Respiratory insufficiency in Guillain-Barre Syndrome patients presenting with sensory symptoms was common.