Viable embedded wormholes and energy conditions in f(R,G)f(\mathcal{R},\mathcal{G}) gravity

The current study explores the generalized embedded wormhole solutions in the background of $f(\mathcal{R},\mathcal{G})$ gravity, where $\mathcal{R}$ represents the Ricci scalar and $\mathcal{G}$ denotes the Gauss-Bonnet invariant. To investigate the necessary structures of the wormhole solutions we thoroughly analyzed the energy conditions under $f(\mathcal{R},\mathcal{G})$ gravity within the anisotropic source of matter. To meet this aim, we consider spherically symmetric geometry with the most generic gravity model of the gravity. A modified version of the field equations is calculated for two different embedded wormhole solutions. All the energy conditions are calculated and shown graphically with the regional ranges of the model parameter. Further, the invalid region of the energy conditions confirms the presence of exotic matter. Finally, we have concluding remarks

Planning, operation, and protection of microgrids : an overview

The significance of microgrids is growing rapidly. Microgrids have a huge potential in boosting the sustainable growth. A microgrid can operate in grid-connected or islanded mode. In islanded mode, microgrids can provide electricity to the rural areas with lower cost and minimum power losses. In grid-connected mode, microgrids can help in supporting the main grid in many ways with voltage control, frequency control, and can provide more flexibility, control, and reliability. However, successful operation of a microgrid requires proper planning and there are major challenges regarding the operation, control, and protection of microgrids that need to be tackled for successful deployment of microgrids. Depending on the mode of operation (grid connected mode or islanded mode), necessary control strategies and protection schemes are required. Several methods have been proposed in the literature for the successful operation of a microgrid. This paper presents an overview of the major challenges and their possible solutions for planning, operation, and control of islanded operation of a microgrid

Telecommunication Infrastructure Development and FDI into Asian Developing Nations

This study strives to evaluate the effects of infrastructure availability and development on foreign direct investment (FDI) in host developing nations. Employing fixed effects panel estimation technique, panel data for 23 Asian developing countries, from 1990-2009 is used with heteroscedasticity corrected standard errors. The results reveal a strong favourable impact of telecom infrastructure (measured by mobile subscriptions) in drawing inward FDI. Therefore, it is concluded that a country with improved infrastructure in general and telecom infrastructure in particular is likely to pull in more FDI. Other variables such as market size, economic development, and currency valuation (measured by exchange rate) appear important in captivating multinational investors, as they exhibit significant coefficients. On the contrary, high-inflation significantly deters inward FDI

A simple and accurate approach to solve the power flow for balanced islanded microgrids

Power flow studies are very important in the planning or expansion of power system. With the integration of distributed generation (DG), micro-grids are becoming attractive. So, it is important to study the power flow of micro-grids. In grid connected mode, the power flow of the system can be solved in a conventional manner. In islanded mode, the conventional method (like Gauss Seidel) cannot be applied to solve power flow analysis. Hence some modifications are required to implement the conventional Gauss Seidel method to islanded micro-grids. This paper proposes a Modified Gauss Seidel (MGS) method, which is an extension of the conventional Gauss Seidel (GS) method. The proposed method is simple, easy to implement and accurate in solving the power flow analysis for islanded microgrids. The MGS algorithm is implemented on a 6 bus test system. The results are compared against the simulations results obtained from PSCAD/EMTDC which proves the accuracy of the proposed MGS algorithm

A novel approach to solve power flow for islanded microgrids using modified Newton Raphson with droop control of DG

The study of power flow analysis for microgrids has gained importance where several methods have been proposed to solve these problems. However, these schemes are complic ated and not easy to implement due to the absence of a slack bus as well as the dependence of the power on frequency as a result of the droop characteristics. This paper proposes simple and e ffec- tive modifications to the conventional method (Newton Raphs on) to compute the power flow for microgrids. The presented metho d provides a simple, easy to implement, and accurate approach to solve the power flow equations for microgrids. The propose d method is applied to two test systems: a 6-bus system and a 38- bus system. The results are compared against simulation result s from PSCAD/EMTDC which validate the effectiveness of the develo ped method. The proposed technique can be easily integrated in current commercially available power system software and c an be applied for power system studies method is applied to two test systems: a 6-bus system and a 38-bus system. The results are compared against simulation results from PSCAD/EMTDC which validate the effectiveness of the developed method. The proposed technique can be easily integrated in current commercially available power system software and can be applied for power system studies

Post-Operative Complications of Surgery for Chronic Subdural Hematoma (SDH) and Prevention

Objective:  The study aimed to determine the rate and type of complications during surgery for treatment of chronic subdural hematoma and assess ways for their prevention. Material and Methods:  A total of 50 patients of chronic SDH were selected from the Neurosurgery Department of Bahawal Victoria Hospital. Patients were treated surgically with a single burr hole evacuation under local anesthesia, introduced a subdural drain, nursed in a head-down position for 24 hours, and given plenty of fluids orally and intravenous route. The surgical technique involved a formation of a single burr hole at the point of maximum density. Results:  Out of 50, 43 patients recovered smoothly postoperatively and discharged on the 7th postoperative day. Two patients were re-operated due to inadequate evacuation or reaccumulation. One patient developed subdural empyema post-operatively and expired in spite of good antibiotic cover. In one patient subdural drain penetrated the brain parenchyma resulting in dysphasia. Another patient formed an intracerebral hematoma due to irrigation of the cavity with pressure. One patient with GCS 4/15 developed seizures postoperatively and expired after one hour. One patient developed gross subdural tension pneumocephalus after removing the subdural drain was re-operated and recovered. Conclusion:  Single burr hole evacuation of chronic SDH under local anesthesia is the most accepted surgical treatment. Using proper aseptic surgical techniques, the introduction of the minimum necessary length of the subdural catheter to avoid penetration into the brain parenchyma, followed by careful irrigation of the subdural cavity can help prevent complications

Spatiotemporal variation in land use land cover in the response to local climate change using multispectral remote sensing data

Climate change is likely to have serious social, economic, and environmental impacts on farmers whose subsistence depends on nature. Land Use Land Cover (LULC) changes were examined as a significant tool for assessing changes at diverse temporal and spatial scales. Normalized Difference Vegetation Index (NDVI) has the potential ability to signify the vegetation structures of various eco-regions and provide valuable information as a remote sensing tool in studying vegetation phenology cycles. In this study, we used remote sensing and Geographical Information System (GIS) techniques with Maximum Likelihood Classification (MLC) to identify the LULC changes for 40 years in the Sahiwal District. Later, we conducted 120 questionnaires administered to local farmers which were used to correlate climate changes with NDVI. The LULC maps were prepared using MLC and training sites for the years 1981, 2001, and 2021. Regression analysis (R2) was performed to identify the relationship between temperature and vegetation cover (NDVI) in the study area. Results indicate that the build-up area was increased from 7203.76 ha (2.25%) to 31,081.3 ha (9.70%), while the vegetation area decreased by 14,427.1 ha (4.5%) from 1981 to 2021 in Sahiwal District. The mean NDVI values showed that overall NDVI values decreased from 0.24 to 0.20 from 1981 to 2021. Almost 78% of farmers stated that the climate has been changing during the last few years, 72% of farmers stated that climate change had affected agriculture, and 53% of farmers thought that rainfall intensity had also decreased. The R2 tendency showed that temperature and NDVI were negatively connected to each other. This study will integrate and apply the best and most suitable methods, tools, and approaches for equitable local adaptation and governance of agricultural systems in changing climate conditions. Therefore, this research outcome will also meaningfully help policymakers and urban planners for sustainable LULC management and strategies at the local level

Monitoring the dynamic changes in vegetation cover using spatio-temporal remote sensing data from 1984 to 2020

Anthropogenic activities and natural climate changes are the central driving forces of global ecosystems and agriculture changes. Climate changes, such as rainfall and temperature changes, have had the greatest impact on different types of plant production around the world. In the present study, we investigated the spatiotemporal variation of major crops (cotton, rice, wheat, and sugarcane) in the District Vehari, Pakistan, from 1984 to 2020 using remote sensing (RS) technology. The crop identification was pre-processed in ArcGIS software based on Landsat images. After pre-processing, supervised classification was used, which explains the maximum likelihood classification (MLC) to identify the vegetation changes. Our results showed that in the study area cultivated areas under wheat and cotton decreased by almost 5.4% and 9.1% from 1984 to 2020, respectively. Vegetated areas have maximum values of NDVI (>0.4), and built-up areas showed fewer NDVI values (0 to 0.2) in the District Vehari. During the Rabi season, the temperature was increased from 19.93 °C to 21.17 °C. The average temperature was calculated at 34.28 °C to 35.54 °C during the Kharif season in the District Vehari. Our results showed that temperature negatively affects sugarcane, rice, and cotton crops during the Rabi season, and precipitation positively affects sugarcane, rice, and cotton crops during the Kharif season in the study area. Accurate and timely assessment of crop estimation and relation to climate change can give very useful information for decision-makers, governments, and planners in formulating policies regarding crop management and improving agriculture yields

Rainfall in the urban area and its impact on climatology and population growth

Due to the scarcity of studies linking the variability of rainfall and population growth in the capital cities of Northeastern Brazil (NEB), the purpose of this study is to evaluate the variability and multiscale interaction (annual and seasonal), and in addition, to detect their trends and the impact of urban growth. For this, monthly rainfall data between 1960 and 2020 were used. In addition, the detection of rainfall trends on annual and seasonal scales was performed using the Mann–Kendall (MK) test and compared with the phases of El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). The relationship between population growth data and rainfall data for different decades was established. Results indicate that the variability of multiscale urban rainfall is directly associated with the ENSO and PDO phases, followed by the performance of rain-producing meteorological systems in the NEB. In addition, the anthropic influence is shown in the relational pattern between population growth and the variability of decennial rainfall in the capitals of the NEB. However, no capital showed a significant trend of increasing annual rainfall (as in the case of Aracaju, Maceió, and Salvador). The observed population increase in the last decades in the capitals of the NEB and the notable decreasing trend of rainfall could compromise the region’s water security. Moreover, if there is no strategic planning about water bodies, these changes in the rainfall pattern could be compromising