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The installation of photovoltaic (PV) system for electrical power generation has gained a substantial interest in the power system for clean and green energy. However, having the intermittent characteristics of photovoltaic, its integration with the power system may cause certain uncertainties (voltage fluctuations, harmonics in output waveforms, etc.) leading towards reliability and stability issues. In PV systems, the power electronics play a significant role in energy harvesting and integration of grid-friendly power systems. Therefore, the reliability, efficiency, and cost-effectiveness of power converters are of main concern in the system design and are mainly dependent on the applied control strategy. This review article presents a comprehensive review on the grid-connected PV systems. A wide spectrum of different classifications and configurations of grid-connected inverters is presented. Different multi-level inverter topologies along with the modulation techniques are classified into many types and are elaborated in detail. Moreover, different control reference frames used in inverters are presented. In addition, different control strategies applied to inverters are discussed and a concise summary of the related literature review is presented in tabulated form. Finally, the scope of the research is briefly discussed.

LCL (inductor–capacitor–inductor) filters are widely used in grid-connected inverters, particularly in electric vehicle (EV) battery-to-grid systems, for harmonic suppression but introduce resonance issues that compromise stability. This study presents a novel sensorless active damping strategy based on μ-synthesis control for EV batteries connected to the grid via LCL filters, eliminating the need for additional current sensors while preserving harmonic attenuation. A comprehensive state–space and process noise model enables accurate capacitor current estimation using only grid current and point-of-common-coupling (PCC) voltage measurements. The proposed method maintains robust performance under ±60% LCL parameter variations and integrates a proportional-resonant (PR) current controller for resonance suppression. Hardware-in-the-loop (HIL) validation demonstrates enhanced stability in dynamic grid conditions, with total harmonic distortion (THD) below 5% (IEEE 1547-compliant) and current tracking error < 0.06 A.

Nowadays, power converters with reduced cost, compact size and high efficiency are evolving to overcome the emergent challenges of renewable energy integrations. In this context, there is an increased demand for well-designed power converters in renewable energy applications to reduce energy utilization and handle a variety of loads. This paper proposes a center-tapped bridge cascaded series-resonant LC dual active bridge (DAB) converter for DC-DC conversion. The low part count of the proposed converter enables a high-power density design with reduced cost. The proposed converter offers reduced conduction losses as the reverse current is eliminated by adopting current blocking characteristics. Reverse current blocking also enables zero voltage switching (ZVS) and zero current switching (ZCS) over a wide operating range. Therefore, using a simple fixed frequency modulation (FFM) scheme offers a wide operating range compared to a conventional DAB converter. A thorough comparison of the proposed converter and a conventional DAB converter is provided based on conduction losses and switching losses to illustrate the performance improvement. Lastly, the effectiveness of the proposed converter is validated through simulation and experimental results.

In South Asia, infectious diseases are associated with significant morbidity and mortality. Malaria, typhoid, and dengue are the most common infectious diseases, and patients may be co-infected with these diseases, resulting in diagnostic and treatment dilemmas. Dengue is caused by the family of viruses and is transmitted by . Dengue virus has four serotypes and the symptoms of dengue fever mimic those of other infectious diseases such as malaria, chikungunya, Zika virus disease, influenza A, enteric fever, and coronavirus disease 2019, which are also prevalent in areas of frequent dengue fever outbreak. Dengue fever is characterized by fever, severe myalgia, retro-orbital pain, skin rashes, and bone pain, which is why dengue fever is also referred to as breakbone fever. Patients with secondary dengue virus infection more commonly present with abdominal pain when compared with those with primary dengue virus infection. causes enteric fever, which is a human infection with no animal reservoir, but the symptoms of enteric fever closely resemble those of dengue fever. Concurrent infections with multiple organisms are especially difficult to diagnose. In this report, we present the case of a 15-year-old boy from Peshawar, Pakistan, who was co-infected with the dengue virus and extensively drug-resistant . To the best of our knowledge, this is the first reported case of co-infection with dengue virus and extensively drug-resistant Salmonella typhi.

The nano-sized TiO2 is an important material based on its application for solar cells. The low-cost synthesis of nano-sized TiO2 is of high demand for commercial purposes. Synthesis of TiO2 nanoparticles was achieved via the low-temperature Sol-gel method. Surface morphology was confirmed from SEM analysis, which showed that particle size is in the range of nanometer with no aggregation, The XRD results confirm the formation of anatase phase with high crystallinity. Furthermore, as prepared nano-sized TiO2 particles were developed as sol-gel ink which was later deposited by spin coating on glass substrate with controlled spinning speed thereafter structural and optical properties were characterized by UV-vis spectroscopy, electrochemical impedance spectroscopy and DSC-TGA. The low-cost synthesis of TiO2 nanoparticles with highly conductive thin films can be used as a potential material for future dye-sensitized solar cells

Bolted joints are widely used in the aerospace and automotive industries due to their ease of assembly, disassembly and design flexibility. Optimizing threaded fasteners is essential to achieve uniform load distribution and minimize the number of bolts required, thereby reducing system cost and weight. This review paper aims at summarizing the five optimization techniques available in the literature, including bolt layout, tightening strategies, tightening sequences, bolt size, and stresses. The purpose is to emphasize the importance of optimizing bolted joints via the proper selection of materials, geometry, patterns, and bolt sizes, to obtain efficient joints with low assembly time while maintaining strength.

This study investigated the purification and refining method for producing a nanometer size zinc oxide (ZnO) from the low-grade ZnO commercial powder using low cost ammonium carbonate solution as a leaching agent. The atomic absorption spectroscopy results show that the concentration of iron, lead and cadmium can be dramatically reduced by ammonium carbonate leaching and washing. X-ray diffraction (XRD) and scanning electron microscope (SEM) results show that structural properties can improve the degree of the preferential c-axis orientation, grain size, and surface morphology of ZnO by solvent evaporation. All physical and chemical results are of particular significance for the preparation of purified ZnO for device fabrication in photovoltaic industry, functional ZnO coatings, and polymer nanocomposite applications.

To efficiently and accurately track the Global Maximum Power Point (GMPP) of the PV system under Varying Environmental Conditions (VECs), numerous hybrid Maximum Power Point Tracking (MPPT) techniques were developed. In this research work, different hybrid MPPT techniques are categorized into three types: a combination of conventional algorithms, a combination of soft computing algorithms, and a combination of conventional and soft computing algorithms are discussed in detail. Particularly, about 90 hybrid MPPT techniques are presented, and their key specifications, such as accuracy, speed, cost, complexity, etc., are summarized. Along with these specifications, numerous other parameters, such as the PV panel’s location, season, tilt, orientation, etc., are also discussed, which makes its selection easier according to the requirements. This research work is organized in such a manner that it provides a valuable path for energy engineers and researchers to select an appropriate MPPT technique based on the projects’ limitations and objectives.

Background & objective: Iatrogenic bile duct injury (IBDI) is a well-established complication of cholecystectomy. Effective management of this complex surgical complication necessitates early referral to high-volume hepatobiliary centers. The sequelae of this injury can lead to biliary peritonitis, recurrent cholangitis, biliary stricture, liver cirrhosis, sepsis, and even mortality. The aim of this study was to thoroughly examine the clinical presentation, injury grading, surgical approaches, and outcomes of patients with IBDI. Methodology: Data of all IBDI patients were collected, and 79 patients were included who underwent surgery between 1st January 2019 to 31st January 2025 at Hepato pancreato biliary department Pakistan Kidney and Liver Institute and Research Centre. Our primary outcomes included the success rate of different surgical procedures, postoperative morbidity and mortality, need for hepatic resection or liver transplantation, and length of hospital stay. Categorical data such as age, gender, risk factors, and diagnosis were presented as frequencies and percentages. Crude odds ratios (ORs) with 95% confidence intervals were determined for the risk of death. Results: A total of 79 patients met the selection criteria, including 18 (22.8%) males and 61 (77.2%) females. The median age of the patients was 43 years (IQR, 34-53 years). The majority of IBDI cases, 48 (60.8%), were treated with hepaticojejunostomy, followed by 16 (20.3%) with redo hepaticojejunostomy, and one patient underwent liver transplantation for secondary biliary cirrhosis. Right hepatectomy with biliary reconstruction was performed in 45.4% of cases with isolated RHA injury. The overall success rate was 96.2%, irrespective of the type of surgery performed. The median follow-up duration for the 77 patients was 20 months (IQR, 11-31 months). Two (2.5%) patients were lost to follow-up after the initial visit, and hospital mortality was observed in 2 (2.5%) patients. There was no statistically significant difference in postoperative complications across the different risk factors or surgical types. Postoperative morbidity occurred in 23 patients (29.1%), and these complications were more pronounced in E5 injuries associated with vascular involvement. Conclusion: IBDI represents a complex surgical complication that demands expertise, and inadequate reconstruction by the index surgeon should not be attempted. Early referral to high-volume hepatobiliary centers is recommended. Complex biliary and vascular injury is an independent risk factor for hepatectomy and significantly prolongs postoperative recovery but does not substantially compromise the long-term outcomes when adequately treated.

In this work, a non-isolated DC–DC converter is presented that combines a voltage doubler circuit and switch inductor cell with the single ended primary inductor converter to achieve a high voltage gain at a low duty cycle and with reduced component count. The converter utilizes a single switch that makes its control very simple. The voltage stress across the semiconductor components is less than the output voltage, which makes it possible to use the diodes with reduced voltage rating and a switch with low turn-on resistance. In particular, performance principle of the proposed converter along with the steady state analysis such as voltage gain, voltage stress on semiconductor components, and design of inductors and capacitors, etc., are carried out and discussed in detail. Moreover, to regulate a constant voltage at a DC-link capacitor, back propagation algorithm-based adaptive control schemes are designed. These adaptive schemes enhance the system performance by dynamically updating the control law parameters in case of PV intermittency. Furthermore, a proportional resonant controller based on Naslin polynomial method is designed for the current control loop. The method describes a systematic procedure to calculate proportional gain, resonant gain, and all the coefficients for the resonant path. Finally, the proposed system is simulated in MATLAB and Simulink software to validate the analytical and theoretical concepts along with the efficacy of the proposed model.