Wind Farms and Flexible Loads Contribution in Automatic Generation Control: An Extensive Review and Simulation

With the increasing integration of wind energy sources into conventional power systems, the demand for reserve power has risen due to associated forecasting errors. Consequently, developing innovative operating strategies for automatic generation control (AGC) has become crucial. These strategies ensure a real-time balance between load and generation while minimizing the reliance on operating reserves from conventional power plant units. Wind farms exhibit a strong interest in participating in AGC operations, especially when AGC is organized into different regulation areas encompassing various generation units. Further, the integration of flexible loads, such as electric vehicles and thermostatically controlled loads, is considered indispensable in modern power systems, which can have the capability to offer ancillary services to the grid through the AGC systems. This study initially presents the fundamental concepts of wind power plants and flexible load units, highlighting their significant contribution to load frequency control (LFC) as an important aspect of AGC. Subsequently, a real-time dynamic dispatch strategy for the AGC model is proposed, integrating reserve power from wind farms and flexible load units. For simulations, a future Pakistan power system model is developed using Dig SILENT Power Factory software (2020 SP3), and the obtained results are presented. The results demonstrate that wind farms and flexible loads can effectively contribute to power-balancing operations. However, given its cost-effectiveness, wind power should be operated at maximum capacity and only be utilized when there is a need to reduce power generation. Additionally, integrating reserves from these sources ensures power system security, reduces dependence on conventional sources, and enhances economic efficiency

Thrombosis with thrombocytopenia syndrome after administration of AZD1222 or Ad26.COV2.S vaccine for COVID-19: A systematic review

Background: Cases of thrombosis with thrombocytopenia syndrome (TTS) have been reported following vaccination with AZD1222 or Ad26.COV2.S. This review aimed to explore the pathophysiology, epidemiology, diagnosis, management, and prognosis of TTS.Methods: A systematic review was conducted to identify evidence on TTS till 4th September 2021. Case reports and series reporting patient-level data were included. Descriptive statistics were reported and compared across patients with different sexes, age groups, vaccines, types of thrombosis, and outcomes.Findings: Sixty-two studies reporting 160 cases were included from 16 countries. Patients were predominantly females with a median age of 42.50 (22) years. AZD1222 was administered to 140 patients (87·5%). TTS onset occurred in a median of 9 (4) days after vaccination. Venous thrombosis was most common (61.0%). Most patients developed cerebral venous sinus thrombosis (CVST; 66.3%). CVST was significantly more common in female vs male patients (p = 0·001) and in patients aged \u3c45 years vs ≥45 years (p = 0·004). The mortality rate was 36.2%, and patients with suspected TTS, venous thrombosis, CVST, pulmonary embolism, or intraneural complications, patients not managed with non-heparin anticoagulants or IVIG, patients receiving platelet transfusions, and patients requiring intensive care unit admission, mechanical ventilation, or inpatient neurosurgery were more likely to expire than recover.Interpretation: These findings help to understand the pathophysiology of TTS while also recommending diagnostic and management approaches to improve prognosis in patients.Funding: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors

State owned enterprises as bribe payers: the role of institutional environment

Our paper draws attention to a neglected channel of corruption—the bribe payments by state-owned enterprises (SOEs). This is an important phenomenon as bribe payments by SOEs fruitlessly waste national resources, compromising public welfare and national prosperity. Using a large dataset of 30,249 firms from 50 countries, we show that, in general, SOEs are less likely to pay bribes for achieving organizational objectives owing to their political connectivity. However, in deteriorated institutional environments, SOEs may be subjected to potential managerial rent-seeking behaviors, which disproportionately increase SOE bribe propensity relative to privately owned enterprises. Specifically, our findings highlight the importance of fostering democracy and rule of law, reducing prevalence of corruption and shortening power distance in reducing the incidence of SOE bribery

Rapid Growth of TiO₂ Nanoflowers via Low-Temperature Solution Process: Photovoltaic and Sensing Applications

This paper reports the rapid synthesis, characterization, and photovoltaic and sensing applications of TiO2 nanoflowers prepared by a facile low-temperature solution process. The morphological characterizations clearly reveal the high-density growth of a three-dimensional flower-shaped structure composed of small petal-like rods. The detailed properties confirmed that the synthesized nanoflowers exhibited high crystallinity with anatase phase and possessed an energy bandgap of 3.2 eV. The synthesized TiO2 nanoflowers were utilized as photo-anode and electron-mediating materials to fabricate dye-sensitized solar cell (DSSC) and liquid nitroaniline sensor applications. The fabricated DSSC demonstrated a moderate conversion efficiency of ~3.64% with a maximum incident photon to current efficiency (IPCE) of ~41% at 540 nm. The fabricated liquid nitroaniline sensor demonstrated a good sensitivity of ~268.9 μA mM−1 cm−2 with a low detection limit of 1.05 mM in a short response time of 10 s

Convenient synthesis of substituted pyrroles via a cerium (IV) ammonium nitrate (CAN)-catalyzed Paal–Knorr reaction

AbstractA screening of various cerium salts for promoting the Paal–Knorr pyrrole synthesis revealed the superiority of cerium (IV) ammonium nitrate (CAN) as a catalyst. Excellent yields of substituted pyrroles were obtained in CAN-catalyzed Paal–Knorr reactions of 1,4-diketones with various amines. The protocol is noteworthy for the mild reaction condition, short reaction times, scalability and easy isolation of products and high yields of the products

Challenging Case of Transcatheter Mitral Valve-In-Valve-In-Valve Replacement

BACKGROUND A 39-year-old man with a complex valvular history of recurrent methicillin-resistant Staphylococcus aureus endocarditis with 2 surgical mitral valve replacements (in 2016 and 2017) followed by transcatheter mitral valve replacement (in 2019) presented with orthopnea, paroxysmal nocturnal dyspnea, chest pain, cough, and progressively worsening dyspnea on exertion. CASE REPORT Extensive workup was performed, including transesophageal echocardiogram, which revealed a malfunctioning, severely stenotic bioprosthetic valve. Left and right heart catheterization revealed mild non-obstructive coronary artery disease and severe pulmonary hypertension. Given the patient\u27s complex medical history, he was deemed to be at an elevated risk for repeat sternotomy and repeat valve replacement surgery. Therefore, he underwent a percutaneous transcatheter mitral valve replacement with a 26-mm SAPIEN 3 Edwards valve placed within the previous 29-mm SAPIEN valve. Post-procedural imaging revealed a well-placed valve with an improved mitral valve gradient. CONCLUSIONS This is one of the few rare cases of mitral valve-in-valve via a transcatheter mitral valve replacement approach with successful deployment of a SAPIEN 3 tissue heart valve. The patient experienced significant reversal of heart failure symptoms and improved exertional tolerance following deployment of the valve and was eventually discharged home in a stable condition

Combination checkpoint blockade for metastatic cutaneous malignancies in kidney transplant recipients

Background Immune checkpoint blockade has emerged as a highly effective treatment for patients with metastatic melanoma and cutaneous squamous cell carcinoma. Nivolumab blocks the interactions between programmed cell death protein 1 and programmed death ligand 1 allowing for activation of a latent immune response against the malignancy. Ipilimumab binds to and blocks cytotoxic T-lymphocyte-associated protein 4, alleviating the negative regulation of T-cell activation that is mediated by that checkpoint. Combination therapy with nivolumab and ipilimumab is associated with longer overall survival at 5 years compared with nivolumab monotherapy. Solid organ transplant recipients have a significantly higher risk of malignancies compared with the general population. There is limited data surrounding the efficacy of combination immunotherapy in solid organ transplant recipients, as these patients were excluded from seminal trials due to risk of organ rejection.Case presentations Here we present four cases of combination immunotherapy in kidney transplant recipients. Three patients had metastatic melanoma, and one patient had metastatic cutaneous squamous cell carcinoma. Two patients had radiographic responses from immunotherapy, one patient had stable disease, and one patient had disease progression. Only one patient had biopsy-proven rejection. At last follow-up, three patients had functioning grafts, though one required hemodialysis after treatment, and one patient succumbed to disease, but graft function remained intact throughout her course.Conclusions These cases describe the use of ipilimumab and nivolumab combination immunotherapy for cutaneous malignancies in kidney transplant recipients. They highlight the potential to preserve kidney graft function while effectively treating the disease