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Switched reluctance machine (SRM) has progressed as a suitable contender in the family of electrical machines for its high starting torque and better performance in different operating conditions. The need for accurate modeling of this machine is therefore dependent on the accurate determination of losses of which iron loss is exigent. This paper aims to determine iron loss from the equivalent circuit parameters of the machine based on the input data tables that are directly obtained from the experiments performed on an existing 4-phase, bifilar wound switched reluctance machine. The procedure and necessary steps for the loss separation method are well defined and supported by the theoretical and practical results. The experimental determination of the iron losses has been compared with the predicted results under the same operating conditions.

Objective: To introduce a relatively convenient and effective way of conducting Insulin Tolerance Test for diagnosis of Growth Hormone deficiency in children with short stature. Study Design: Cross sectional analytical study. Place and Duration of Study: Conducted at Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology, Rawalpindi, from May 2017 to Jul 2018. Methodology: A total of 185 cases were included. Sample selection was done by non-probability consecutive sampling technique. Insulin tolerance test was performed by taking basal sample for serum growth hormone and plasma glucose levels before giving intravenous insulin bolus according to dose of 0.15 IU/kg. Samples for Growth Hormone level were repeated at time of induced hypoglycemia (defined as plasma glucose level of 20 mIU/l) at induction alone, followed by 30 minutes post induction; reflecting the significance of these two samples in diagnosis of growth hormone deficiency. Conclusion: We concluded that there is a simpler ...........

Objective: To determine the diagnostic accuracy of immunoassays in drug screening as required in emergency for the rapid diagnosis of drug intoxication in travel related crimes. Study Design: Diagnostic accuracy study. Place and Duration of Study: department of Chemical Pathology and Endocrinology, Armed Forces Institute ofPathology, Rawalpindi Pakistan, from Jul 2017 to Jun 2018. Methodology: Sealed urine specimens of 77 patients with history of suspected intoxication in drugs facilitatedstreet crimes, received for toxicology screening were included in the study. All the specimens were analysed,initially on immunoassay (index test) and then on Triple Quadrupole Liquid chromatography–Mass spectrometry (reference standard). Benzodiazepine being the main class of drugs involved in travel related crimes, diagnostic accuracy of immunoassay technique was assessed for these by calculating its sensitivity, specificity, positive predictive value and negative predictive value. Results: Victims were predominantly males and public transportation was the most common mode of transport. The most commonly used drug was Lorazepam. Immunoassay failed to detect few cases who were shown to be intoxicated with benzodiazepines by liquid-chromatography tandem mass spectrometry. The false negative rate was 4.9%. Only one false positive case was observed. The accuracy was calculated to be 94.8% with sensitivity of 95.08% and specificity of 93.7%. Conclusion: Immunoassay was found reliable for rapid testing in drug facilitated intoxication cases. Howevercritical decision making should be done cautiously keeping in mind the limitations associated with thesescreening procedures.

Solar-energy is a clean source of energy and photovoltaic (PV) panels are constructed from solar cells (SC) which convert energy of light into electricity without any environmental effect. The researchers and policy makers focus on the huge scale adoption of solar panels due to its cleaner production. However, there is non-linear behavior in current-voltage characteristics of solar panels and shortage of data in manufacturer’s datasheet. In order to enhance the efficiency of solar panels it is mandatory to develop the PV panels scheme accurately by extracting the basic parameters. In this research study a mathematical model of two different solar cell models is used such as Single Diode Model (SDM) and Double Diode Model (DDM). The Particle Swarm Optimization (PSO) is used to extract the five and seven unknown parameters of SDM and DDM. The algorithm runs with one thousand iterations to minimize the Root Mean Square Error (RMSE) where the RMSE is the vector of five unknown parameters for SDM and seven for DDM. The superiority of proposed PSO algorithm is proved by the optimized results of unrevealed parameters with minimized RMSE of up to 10-3. Optimum parameter values for the solar cell models are applied on the real time data of a 55 mm diameter commercial RTC-France SC. Finally, the results reveal that P-V and I-V curves exhibit smallest deviation between estimated and real time values. The results reveal that the proposed PSO converges to optimal solution with least number of iterations compared to the existing metaheuristic algorithms.

Switched Reluctance Machine (SRM) is the advanced version of the stepper motor and since last decade, it is of high interest among researchers and industrial applications. Modelling an SRM relies on accurate data and proper selection of parameters. The next step is the performance analysis of the machine for which losses determination is indispensable. Previous studies have shown losses calculation only at a particular instant of switching of the machine (i.e., conduction angle). Therefore, the impact of losses in a motoring region cannot be justified. This paper investigates the impact of varying conduction angle on the performance of machines for a set of switch-on angle. Losses are calculated and predicted through simulating motor operating parameters carried out in MATLAB environment and accuracy of results are compared with experimental results.

An appropriate numerical computational method and simplest model captures the performance of Switched Reluctance Machines (SRMs). Several papers and computer software-based simulation models are reported in the literature. Each model has its own merits and demerits. This paper proposes a mathematical model, based on a combination of voltage and mechanical equations, suitable for the transient running of a switched reluctance machine. The simulation results of current, torque and speed profile of SRM are produced under current chopping control and voltage pulse width modulation control. The proposed work has used experimental data of flux linkage and static torque in the mathematical model for best performance and control of the machine. The obtained simulation results are verified with experimental results. This model can be extended to a range of rotor position where the machine can be switched at decreased and increased inductance region which gives motoring and generating operation mode.

The increasing popularity of the switched reluctance machine has created more challenges to present it as a good performer machine under different operational conditions. For modeling and simulation of the machine, the necessity of static characteristics, in particular, flux linkage characteristics which look like the base stone for initialization of simulation is unavoidable. The importance of flux linkage characteristics, and how other data tables such as inverter flux linkage characteristics, co energy and static torque table are obtained are presented in this work. This paper describes a set of equations for modeling of the flux linkage characteristics of switched reluctance machine and also hardware for the 3-phase machine is presented. Keywords: Flux Linkage Characteristics, Inductance Profile, Switched Reluctance Machine

This paper proposes a novel brushless excitation topology for a three-phase synchronous machine based on a customary current-controlled voltage source inverter (VSI). The inverter employs a simple hysteresis-controller-based current control scheme that enables it to inject a three-phase armature current to the stator winding which contains a dc offset. This dc offset generates an additional air gap magneto-motive force (MMF). On the rotor side, an additional harmonic winding is mounted to harness the harmonic power from the air gap flux. Since a third harmonic flux is generated in this type of topology, the machine structure is also modified to accommodate the third harmonic rotor winding to have a voltage induced as the rotor rotates at synchronous speed. Specifically, four-pole armature and field winding patterns are used, whereas the harmonic winding is configured for a twelve-pole pattern. A diode rectifier is also mounted on the rotor between the harmonic and field windings. Therefore, the generated voltage on the harmonic winding feeds the current to the field winding for excitation. A 2D-finite element analysis (FEA) in JMAG-Designer was carried out for performance evaluation and verification of the topology. The simulation results are consistent with the proposed theory. The topology could reduce the cost and stator winding volume compared to a conventional brushless machine, with good potential for various applications. National Research Foundation of Korea | Ref. 2016R1D1A1B01008058 National Research Foundation of Korea | Ref. 2019H1D3A1A01102988 Korea government Ministry of Trade, Industry and Energy | Ref. 20204030200090

In the last few decades, wind energy has become a significant source of the renewable energy system, and it is essential to use wind energy for generating power and run the wind turbine system (WTs) at a higher level. With the rapid penetration of wind energy in the distributed generation system (DGS) and isolated micro-grid (MG), the WT runs at its optimal energy conversion output. For this, WT has to track or drive at the optimal power point tracking algorithm. However, various publications are available on MPPT algorithms for wind energy system (WES) applications, making a choice on exact trackers for a particular algorithm because each tracker has its advantages and disadvantages. Therefore, our primary goal is to review and evaluate the exact tracking algorithm for WES applications in this manuscript. To introduce the power controller, it is essential to track maximum power despite wind energy results. Besides, many algorithms have been evaluated, and their maximum output is achieved compared to their performance. This research paper will help researchers provide an accurate reference for future recommendations by selecting the best tracking algorithms in WES.

This paper presents a proposed model of a multi-stack slotted stator axial-flux type permanent magnet synchronous machine (AFPMSM) specifically for reducing torque ripple. The proposed AFPMSM model uses pentagon-shaped permanent magnets (PMs). It has a low value of cogging torque and torque ripples compared to the conventional model with a trapezoidal magnet shape. Additionally, it has increased internal generated voltage (Ef) as compared to the conventional model. To further enhance Ef phases and minimize cogging torque of the proposed model, the proposed AFPMSM model was optimized by varying different sides of PMs using a genetic algorithm (GA). A time-stepped three-dimensional (3D) finite element analysis (FEA) was performed for the comparative analysis of conventional, proposed, and optimized AFPMSM models. From this comparative performance analysis, it is observed that torque ripples and cogging torque of the optimized AFPMSM are significantly decreased, while output average torque is appreciably increased. Ef and output power are also enhanced.

The significance of the modern fractional derivatives containing the singular kernel with locality and the non-singular kernel with non-locality have recently diverted the researchers because of the numerical or experimental analyses on the behavior between a system conservative and dissipative and the lack of fractionalized analytic methods. This study investigates the effects of modern fractional differentiation on the RLC electrical circuit via exact analytical approach. The modeling of governing differential equation of RLC electrical circuit has been fractionalized through three types of fractional derivatives namely Caputo, Caputo-Fabrizio and Atangana-Baleanu fractional derivatives based on the range as $$0 \le \alpha \le 1,\,\,0 \le \beta \le 1,\,\,0 \le \gamma \le 1$$ respectively. The RLC electrical circuit is observed for exponential, periodic and unit step sources via three classified modern fractional derivatives. The exact analytical solutions have been investigated by invoking mathematical Laplace transforms and presented in terms of convolutions product and special function namely Fox-H function. The Comparative mathematical analysis of RLC electrical circuit is based on Caputo, Caputo-Fabrizio and Atangana-Baleanu fractional derivatives which exhibit the presence of heterogeneities in the electrical components causing irreversible dissipative effects. Finally, the several similarities and differences for the periodic and exponential sources have been rectified on the basis of the Caputo, Caputo-Fabrizio and Atangana-Baleanu fractional derivatives for the current.

Objective To evaluate the effect of bilirubin interference on plasma amino acid analysis by Ion Exchange Chromatography (IEC). Study design Cross-sectional (method validation) study. Place and duration of study Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology, Rawalpindi from August 2016 to July 2017. Methodology Twenty non-icteric samples from paediatric patients were collected in lithium heparin tubes and analysed for amino acids on IEC-based Biochrome® 30+ Analyzer (Harvard Biosciences UK). Baseline bilirubin levels were noted. Samples were spiked with neonatal bilirubin standard with concentration of 488.4 mol/L (Spinreact®-Spain) at final concentrations of 50, 150 and 230 mol/L and re-analysed for amino acids at these three concentrations. Results Among the 20 selected patients with normal amino acid profiles, 12 (60%) were males. Majority (55%) were in age group of 1-5 years. Significant difference was observed for Arginine (p = 0.01), Histidine (p = 0.001), Isoleucine (p = 0.01), Leucine (p = 0.007), Lysine (p = 0.005), Ornithine (p = 0.03) and Phenylalanine (p = 0.02). Mean rank of these amino acids showed decreasing trend with the increase of bilirubin concentration, and pronounced interference was identified at bilirubin level of 50 mol/L. No difference was observed for alanine, citrulline, glutamic acid, glycine, methionine, proline, threonine, tyrosine, asparagine, aspartic acid, cystine, valine and tryptophan. Conclusion Bilirubin significantly interferes with certain amino acid levels when analysis is carried out by ion exchange chromatography. A close follow-up of such patients with other biochemical tests and a repeat amino acid analysis, after jaundice is settled, is recommended to confidently rule out any possible inherited metabolic disorder in these patients.

Adult growth hormone deficiency (AGHD) syndrome has a constellation of features, like impaired cognitive function, altered body composition, poor quality of life and various metabolic changes. Most of its features resemble signs of aging as growth hormone (GH) secretion decreases with age. Hypothalamic-pituitary-adrenal (HPA) axis should be thoroughly investigated in this disease as patients with AGHD are at risk of life-threatening consequences due to partial or complete ACTH deficiency, especially in stressful conditions. GH deficiency has also been related to diabetes or glucose intolerance. It is relatively underdiagnosed problem in adults and requires a thorough workup including dynamic function tests like insulin tolerance test (ITT), which has been termed as the gold standard for the diagnosis of patients with ACTH deficiency.

This study presents the optimization of algal biomass catalytic gasification for hydrogen-rich gas production. Three operating parameters under varying conditions of temperature (700–900 °C), catalyst loading (5–20 wt%) and reaction time (15–40 min) were optimized. The central composite design (CCD) was used to perform optimization and to investigate the influence of operating parameters on response variables (fractions of H2, CO, CO2 and CH4). The results indicated the temperature and catalyst loading as the most significant reaction parameters influencing H2 production and reducing the tar produced during the gasification process. The highest H2 fraction of 48.95 mol% (18.77 mol kg-biomass−1) was obtained at an optimum condition at 851 °C with catalyst loading of 16.4 wt% and reaction time of 28.8 min. The high R2 values of 0.98, 0.97, 0.95, and 0.90 corresponding to the response variables (H2, CO, CO2 and CH4) showed paramount estimation of model.

Switched reluctance motor (SRM) is an energy efficient machine, which receives electrical energy from the power source and returns part of the stored magnetic energy back to the supply, during each cycle of the machine operation. Characteristically, the SRM possesses nonlinear characteristics due to dual saliency and magnetic saturation. The exertion is realized in developing a mathematical model of the machine in presence of huge input data tables, famously, known as static characteristics. These data tables are required for mathematical modeling of the machine in a single pulse, steady state and transient performances separately. This paper presents a simple and flexible mathematical model of a switched reluctance machine in MATLAB/Simulink environment. In Simulink, based on graphical coding environment, the proposed model uses fewer data tables and less simulation time. Furthermore, with less addition to the same proposed model, another operating mode of the machine is possible, under the same operating conditions. A similar model in MATLAB, based on test code environment is also proposed, using the same operating conditions as in the Simulink based model to see the difference. The obtained results are validated by comparing the results of both the models, and with the experimentally obtained results, under single pulse, steady-state, and dynamic modes of the machine operation. The proposed model can handle the measured or computed data of the flux linkage and static torque, respectively.

It is highly imperative to recover energy from not only the lipid fraction of microalgae but also the residual biomass after lipid-extraction to augment energy potential and to facilitate the sustainability of algal-based bioenergy. Herein, we present the production of syngas from microalgae residual biomass (Chlorella vulgaris), upon its extraction as by-product from biodiesel production system, in a lab-scale fixed bed reactor (FBR). The influences of two gasification parameters such as temperature (700, 800 and 900 °C) and catalysts type (Y2O3, Ni and eggshell derived CaO) have been studies in terms of CnHm/CO/H2 gas yield and composition, carbon conversion efficiency (CCE%), lower heating value (LHV) of syngas under 5% O2 and 95% Ar gasification environment. From the results, 800 °C was found to be an optimum temperature producing highest H2 yield (4.53 mmol g−1 biomass with purity of 34.62 vol%) and highest generation peak intensity of 0.14 mmol min−1 g−1, whereas highest LHV (8.92 MJ N m−3), total gas yield (73.54 wt%) and CCE (49.54%) were obtained at 900 °C. Addition of catalysts further improved H2 yield and its volume fraction, total gas yield and CCE%. The Ni catalyst was found to be the most effective catalyst in terms of the maximum H2 yield (8.22 mmol g−1 biomass with purity of 56.12 vol%), highest total gas yield of 80.21 wt%, and CCE of 49.06% owing to its relatively high catalytic activity for promoting water-gas shift, as well as tar and char reforming reactions. The average LHV of syngas was obtained to be 9 MJ N m−3. Furthermore, the considerable decrease in tar and char contents from 20.12 wt% and 21.77 wt% (without catalyst at 700 °C) to 9.32 wt% and 10.47 wt% (with Ni catalyst) was recorded.

OBJECTIVE To determine the clinical and biochemical pattern of parathyroid disorders in a tertiary care setting.. METHODS The cross-sectional study was conducted at the Armed Forces Institute of Pathology, Rawalpindi, Pakistan, from September 2017 to February 2018, and comprised patients with suspected parathyroid disorders. A panel of biochemical tests were used for diagnosis of parathyroid disorders, which included parathyroid hormone levels, total calcium, ionized calcium, inorganic phosphorus, alkaline phosphatase, magnesium, total vitamin D and urinary calcium-to-creatinine ratio. SPSS 24 was used for data analysis. RESULTS Of the 384 subjects, 248(65%) were male and 136(35%) were female. Overall mean age was 48±19years. Of the total, 302(786%) had parathyroid issues, with 244(81%) having secondary hyperparathyroidism. Mean serum total calcium, phosphorus, ionized calcium, magnesium and total vitamin D were 8.98±1.52 mg/dl, 4.0±1.30 mg/dl, 4.65±0.52 mg/dl, 2.11±0.27 mg/dl and 20.5±8.52 ngml respectively. Of the patients diagnosed with secondary hyperparathyroidism, 72.2% patients had chronic kidney disease and 20.2% had isolated vitamin D deficiency. CONCLUSIONS Parathyroid disorders had significant impact on bone health. Moreover, secondary hyperparathyroidism was seen to be emerging as a major endocrine problem, especially in chronic kidney disease patients and vitamin D-deficient individuals.

Pseudohypoparathyroidism (PHP) is an extremely rare group of disorders. It is a spectrum of disorders caused by end organ resistance to parathyroid hormone (PTH) and is represented by impaired signalling that activates cAMP dependent pathways via alpha subunit of G-protein (GS). It is characterised by hypocalcemia, hyperphosphatemia, raised PTH levels due to insensitivity to biological activity of PTH, and normal renal function tests. We describe a case of 10-year girl who presented with fear of falling down from heights. Her laboratory evaluation and skeletal survey showed evidence of PHP along with features of Albright's hereditary osteodystrophy (AHO) pointing towards the diagnosis of PHP type 1a.

Identifying and tackling indispensable developments in microalgae-based bio-economy should be a priority to unravel the contentious water-food-energy-environment nexus that algae inhabit. This research investigated the catalytic and non-catalytic steam gasification of two types of lipid-extracted microalgae biomasses, Chlorella vulgaris and Spirulina platensis in a thermogravimetric analyzer coupled with online mass spectrometry. A hybrid-functional mixture consisting of CaO naturally derived from waste eggshell as catalyst and sorbent, Ni as catalyst and Y2O3 as support was employed during the gasification that mainly generated H2, CO and CO2. The varied CaO loading (10 to 50 wt%) showed an evident effect on the overall gasification of lipid-extracted microalgae biomass, indicating an optimal CaO loading of 40 wt% for Ni-CaO-Y2O3 mixed materials which enabled 400.81 and 324.93 mL g−1 of H2 yield, with maximum purity of up to 53.25 and 41.82 vol% in gaseous product for Chlorella vulgaris and Spirulina microalgae residues, respectively. The addition of Ni, Y2O3 in mixed form (Ni-CaO, Ni-CaO-Y2O3, CaO-Y2O3 and Ni-Y2O3) drastically enhanced H2 yield and its purity. Ni-CaO produced the maximum H2 yield and purity of 497.29 and 435 mL g−1, and 63.15 and 45.78 vol% for Chlorella vulgaris and Spirulina platensis, respectively.

The environmental problems and associated issues had been a source of worry for the world. Emerge of IoT (Internet of things) and the step towards the smart approach such as smart cities, smart buildings, and smart grid have really posed the successful implementation of IoT. The success is only possible in the real sense when the problematic issues can be addressed. This paper proposes an Internet of Things Technology based protection and monitoring of environment of a poultry house. The proposed software based hardware is capable of monitoring the environment related parameters such as air temperature, air humidity, O2, CO2 level of concentration and NH3 concentration. The wireless sensor is responsible for the effective data collection of the described parameters and also these are source coordination and control. The hardware is implemented successfully at different sites within the poultry shed. The experimental setup was found very effective and accurate. This scheme will earn a safe environment and profit to the poultry industry.

The green energy sources such as wind and solar energy are main contributors of the modern distribution grid, called smart grid. The variation in the green energy sources causes unintentional operation of the power transformer which is the main part of the smart grid. Power quality, reliability and availability of electrical energy at the consumer's end has been a top priority of the electrical power supply companies. The smart grid desires to have environmentally friendly and an efficient distributed generation. The priority for a smart grid is not only the combination of smart sensors and automated operation of different sections at the grid but the better performance of electrical power system. This can be achieved by continuous monitoring and control of transformers which is very important part of the electrical power system. This paper proposes an Arduino with GSM modem for remote monitoring, protection, and control of the transformer. The software-based hardware provides an easy and effective way of implementation of protection system for the distribution transformer from over current, over voltage, humidity, oil temperature and winding temperature, separately. If any of the specified parameters exceed the pre-set value, then it takes corresponding protective action and also sends the information to the provided mobile number. Furthermore, the message can also be sent from the cell phone to the related control sections for further actions regarding the control and the status of different parameters at the transformer at the yard. The software-based hardware is easy and friendly for the user and can be portable to either location. The automated action of the proposed circuit is helpful particularly in autotransformer at power grid, and it is a progressive forward step towards the smart grid and distributed generation.

Conventional cellular networks are gradually becoming heterogeneous due to deployment of femtocells within cellular networks. Femtocells have been considered by the wireless industry as a promising solution not only to improve indoor coverage and capacity but also to unload traffic from already overburdened macro base stations. Therefore, effective mitigation of both cross-tier and co-tier interference is a major design challenge hetereogenuous cellular networks. In this work stochastic geometry based model is developed for two-tier (macro-femto) heterogeneous cellular networks by using Matern hardcore point process leveraging results on Voronoi tessellations. Complex system level simulations are used to evaluate SIR performance, coverage and capacity of networks. This paper considers fractional frequency reuse to mitigate co-tier and cross-tier interferences. Simulation results confirm significant improvement in coverage, and capacity of the networks using proposed model.

Sleepiness behind the wheel is the major contribution to fatal accidents. Recognizing the drowsiness of the driver is one of the surest methods for measuring driver drowsiness. In this paper a tracker has been created which plans to evaluate driver's fatigue, exhaustion, and diversion throughout driving. The framework composed is a non-intrusive constant checking framework and it consists of camera which keeps a vigilant eye on driver's movements to detect drowsiness. The algorithm developed is unique to any currently published papers, which was a primary objective of the project. The system deals with detecting eyes in an extracted image from video input. All the possible actions have been considered and output is generated accordingly. Drowsiness is determined by observing the eye blinking patterns of the driver. If eyes are found to be closed for a particular time period given by threshold value, the framework reaches the determination that the driver is nodding off and issues a notice flag. The system is implemented using Haar cascade object detector using OpenCV (Open Source Computer Vision Library), which detects eyes from the input image. The system is also able to work under low lighting conditions.

There is a variety of converter topologies applicable for switched reluctance machine. The simplicity, reliability, and suitability are key factors to consider for converter selection for the motor. The selection of switching schemes is also of worth importance for either converter selection. This paper presents the calculation method of switching losses in asymmetrical H-bridge converter for the motor. The data of energy loss is experimentally obtained and then included in the simulation model of the machine to predict the converter losses. The experimental based input data suits the trend of energy loss for a range of current.

This manuscript presents the modeling and control design for a variable speed wind energy conversion system (VS-WECS). This control scheme is based on three-phase squirrel cage induction generator driven by a horizontal-axis wind turbine through the overhead transmission network. In this manuscript, a static VAR compensator is proposed and connected with the squirrel cage induction generator terminals in order to regulate the system parameters, such as voltage, power. Through the pitch angle, the mechanical power was controlled through Simulink (Matlab) software. From the simulation results, the response of the proposed system offers good robustness and fast recovery under various dynamic system disturbances.

The huge deficiency of electricity due to heavy reliance on imported fuels has become a significant impediment to socio-economic development in Pakistan. This scenario creates an increase in local fuel prices and limits potentials in the establishment of new industrial zones. The current gap between the demand and production of electricity in Pakistan is approximately 5000–8000 MW with a constant increase of 6–8 % per annum. Hence, more sustainable and renewable energy sources are required to overcome the existing problem. Pakistan is endowed with potential renewable energy resources such as wind, solar, hydro, and biomass. These resources have the capacity to be major contributors to future energy production matrix, climate change reduction efforts, and the sustainable energy development of the country. This article reviews the availability of alternative energy resources in Pakistan and associated potentials for full-scale development of sustainable energy systems. It also discusses exploitation strategies to increase the distribution of indigenous energy resources.

International audience; This contribution deals with a computational investigation highlighting the effects of cutting speed and depth of cut on chip morphology and surface finish for down-cut milling case. the global aim concerns the comprehension of multiphysical phenomena accompanying chip formation in rough, semifinish, and finish cutting operations, exploiting a three-dimensional finite element model. numerical work has been performed in two phases. in the first phase, a three-dimensional model for rough cut operation has been validated with the experimental results, including chip morphology and cutting force evolution for an aerospace grade aluminum alloy a2024-t351. in the second phase, the model has been extended to semifinish and finish three-dimensional cutting operations. the numerical findings show that as depth of cut decreases (toward finish cutting), spatial displacement of workpiece nodes along the depth of cut increases. this represents an increase/extension in the percentage of volume undergoing shear deformation, resulting in higher dissipation of inelastic energy, hence contributing to size effect in finish cutting operation. the results also depict that material strain rate hardening enhances the material strength at higher cutting speeds. these material strengthening phenomena help to generate a smooth continuous chip morphology and better surface texture in high-speed finishing operations. the study highlights the significance of three-dimensional numerical modeling to better understand the chip formation process in semifinish and finish machining operations, regardless of the immense effort in computational time.

The article “Functionality of circuit via modern fractional differentiations”, written by Kashif Ali Abro, Ali Asghar Memon and Anwar Ahmed Memon, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on November 2018 with open access.

Rural electrification is a fundamental step towards achieving universal access to electricity by 2030. On-grid rural electrification remains a costly proposition, therefore the need to consider off-grid renewable energy solutions is inevitable. However, the critical issue pertaining to local power generation through renewable energy is the absence of area-specific production capacity and economic viability data for the different renewable energy technologies. This paper addresses this issue for Pakistan&rsquo, s Balochistan province by assessing the area&rsquo, s potential and economic feasibility of using solar PV for rural electrification. The results suggest that the Balochistan province has the best solar irradiance value in the world. Furthermore, optimal tilt angles calculated for respective regions can significantly increase solar energy yield. The economic feasibility study, carried out for solar PV systems, reveals that the electricity generated using solar PV costs Rs. 7.98 per kWh and is considerably cheaper than conventional electricity, which costs approximately Rs. 20.79 per kWh. Similarly, solar PV systems could mitigate 126,000 metric tons of CO2 annually if 100% of the unelectrified households adopted solar PV systems. Based on these research findings, this paper proposes a policy that would serve as a guideline for the government to extend solar PV-based off-grid rural electrification projects in Balochistan as well as on a national scale.