Evaluating a Hybrid Circuit Topology for Fault-Ride through in DFIG-Based Wind Turbines.

Large-scale wind power integration has raised concerns about the reliability and stability of power systems. The rotor circuit of a doubly fed induction generator (DFIG) is highly vulnerable to unexpected voltage dips, which can cause considerable electromotive force in the circuit. Consequently, the DFIG must fulfil the fault-ride through (FRT) criteria to ensure the system's performance and contribute to voltage regulation during severe grid outages. This paper provides a hybrid solution for DFIG wind turbines with FRT capabilities, using both a modified switch-type fault current limiter (MSFTCL) and a direct current (DC) chopper. The proposed system has the merit of keeping the rotor current and the DC-link voltage within the permissible limits, enhancing the FRT capability of generators. Moreover, the boundness of supply voltage into its reference value ensures dynamic stability during symmetric and asymmetric grid failures. Further, electromagnetic torque variations are significantly reduced during fault events. Finally, the performance validation of the proposed scheme is performed in a simulation setup, and the results are compared with the existing sliding mode control (SMC) and proportional-integral (PI) controller-based approaches. The comparison results show that a hybrid strategy with advanced controllers provides superior performance for all critical parameters.

New Horizons: COVID-19 and the Burden of Neuropsychiatric Illness in Pakistan.

This manuscript reviews the current state of knowledge about the burden of mental illness and assesses the impact of COVID-19 illness on mental health in Pakistan. For this we analyzed secondary data obtained from the Institute of Health Metrics and Evaluation. The Global Burden of Disease (GBD) study draws from a wide range of data sources to quantify global and regional effects of a disease. We also did a literature search on the effects of COVID-19 illness on mental health and the psychosocial effects of COVID-19 and other Corona virus related illnesses such as SARS-CoV and MERS-CoV. Data from the studies obtained was utilized to extrapolate the anticipated effects of COVID-19 illness on healthcare workers, COVID-19 patients and the general public in Pakistan. Mental illness poses a significant challenge to Pakistan's under resourced health care system. COVID-19 has the potential to strain Pakistan's healthcare system to the breaking point. So far, the general morbidity from COVID-19 illness in Pakistan has been low compared to other countries but this could change in the coming weeks and months. Hidden within this crisis are also some opportunities for both healthcare and education.

Exploring diet, exercise, chronic illnesses, occupational stressors and mental well-being of healthcare professionals in Punjab, Pakistan.

OBJECTIVE: This data set was compiled to assess mental well-being, dietary pattern and physical health parameters of health care professionals in Pakistan. DATA DESCRIPTION: The Warwick-Edinburgh mental well-being scale was first evaluated for the Pakistani population then used, along with other measures like body mass index, exercise and dietary habits to assess health and wellbeing of health care providers. The importance of the data lies in the fact that no previous records or data exists in our knowledge that used a subjective index to assess wellbeing in Pakistani population. Furthermore, this data may be used as part of a global analysis to find differences in well-being and health habits of health care providers in developing countries as opposed to developed countries.

Case of undiagnosed pneumocystis pneumonia (PCP).

Pneumocystis pneumonia (PCP) is an opportunistic fungal infection that is usually seen in immunocompromised patients, especially those with HIV, malignancies, organ transplants and on drug therapies like chemotherapy and steroids. PCP has subacute presentation in patients with AIDS which if left untreated gets worse and is a significant cause of morbidity and mortality. Here we present a case of PCP went undiagnosed, partially due to the patient being unaware of his HIV positive status and partially because no organism could be found under the microscope.

Effective solubilization and single-step purification of Bacillus licheniformis alpha-amylase from insoluble aggregates.

A high level expression of thermostable alpha-amylase gene from Bacillus licheniformis in Escherichia coli was obtained. The recombinant enzyme was mainly produced in the form of insoluble aggregates. The enzyme was solubilized without using denaturing agents and purified to homogeneity in a single step by ion exchange chromatography. The enzyme was purified 138-fold with a final yield of 349 %; the specific activity of the purified enzyme was 1343 U/mg.