Utilization of Solar Energy in Irrigation Systems in Bangladesh

The demand for water pumping in urban water supply and irrigation in Bangladesh is significantly influenced by electricity deficits and high diesel costs. To address these challenges, the adoption of solar power for water pumping emerges as a viable alternative to traditional systems reliant on grid power and diesel. In recent years, there has been a growing emphasis on clean and renewable energies, aligning with the environmental and economic priorities of Bangladesh. The agricultural sector, serving as the backbone of the country’s economy, witnesses an escalating demand for water as the population increases. The extraction and transfer of water for agricultural and drinking purposes translate to high-energy consumption. Leveraging the abundant and essentially free solar energy, particularly during the crop growth periods when irrigation is crucial, presents an optimal solution. This study underscores the underutilization of this vital resource in Bangladesh and advocates for the widespread implementation of solar energy conversion programs, specifically in photovoltaic pumping systems. By comparing these systems with conventional diesel pumps, this paper aims to inspire policymakers, statesmen, and industry professionals to integrate green energy into the water sector. The envisioned outcome is a strategic shift towards sustainable development, with a focus on harnessing solar power to pump water for villages and agriculture, thus contributing to economic and environmental sustainability.

XPS Study of Electroless Deposited Sb2Se3 Thin Films for Solar Cell Absorber Material

As a thin film solar cell absorber material, antimony selenide (Sb2Se3) has become a potential candidate recently because of its unique optical and electrical properties and easy fabrication method. X-ray photoelectron spectroscopy (XPS) was used to determine the stoichiometry and composition of electroless Sb2Se3 thin films using depth profile studies. The surface layers were analyzed nearly stoichiometric. But the abundant amount of antimony makes the inner layer electrically more conductive.

Simulation Study of CuO-Based Solar Cell with Different Buffer Layers Using SCAPS-1D

In copper oxide (CuO) based solar cells, various buffer layers such as CdS, In2S3, WS2 and IGZO have been investigated by solar cell capacitance simulator (SCAPS) in this work. By varying absorber and buffer layer thickness, photovoltaic parameters (open circuit voltage, fill factor, short-circuit current density and efficiency) are determined. The highest efficiency achieved is 19.6% with WS2 buffer layer. The impact of temperature on all CuO-based solar cells is also investigated.

Simulation Study of Nanoscale FDSOI MOSFET Characteristics

Silicon on insulator (SOI) technology permits a good solution to the miniaturization as the MOSFET size scales down. This paper is about to compare the electrical performance of nanoscale FD-SOI MOSFET at various gate lengths. The performance is compared and contrasted with the help of threshold voltage, subthreshold slope, on-state current and leakage current. Interestingly, by decreasing the gate length, the leakage current and on-state current are increased but the threshold voltage is decreased and the sub-threshold slope is degraded. Silvaco two-dimensional simulations are used to analyze the performance of the proposed structures.

Depth Profile Study of Electroless Deposited Sb2S3 Thin Films Using XPS for Photovoltaic Applications

Sb2S3 has gained tremendous research recently for thin film solar cell absorber material because of their easy synthesis, unique electrical and optical properties. The stoichiometry and composition of electroless Sb2S3 thin films were analyzed using XPS depth profile studies. The surface layers were found nearly stoichiometric. On the other hand, the inner layer was rich in antimony composition making it more conductive electrically.

Simulation Study of 50 nm Gate Length MOSFET Characteristics

With the need to improvement of speed of operation and the demand of low power MOSFET size scales down, in this paper, a 50 nm gate length n-type doped channel MOS (NMOS) is simulated using ATLAS packages of Silvaco TCAD Tool so as to observe various electrical parameters at this gate length. The parameters under investigation are the threshold voltage, subthreshold slope, on-state current, leakage current and drain induced barrier lowering (DIBL) by varying channel doping concentration, drain and source doping concentration and gate oxide thickness.

XPS Depth Profile Study of Sprayed Ga2O3 Thin Films

Ga2O3 thin films were fabricated by spray pyrolysis method using gallium acetylacetonate as source material and water as oxidizer. The films were annealed at 450°C for 60 minutes in argon atmosphere. X-ray photoelectron spectroscopy (XPS) depth profile studies were carried out to analyze the stoichiometry and composition of sprayed as-deposited and annealed Ga2O3 thin films. Surface layers and the inner layers of as-deposited and annealed films were found nearly stoichiometric.

Investigation of Sprayed Lu2O3 Thin Films Using XPS

Spray pyrolysis method was used to deposit Lutetium Oxide (Lu2O3) thin films using lutetium (III) chloride as source material and water as oxidizer. Annealing was carried out in argon atmosphere at 450°C for 60 minutes of the films. To investigate the composition and stoichiometry of sprayed as-deposited and annealed Lu2O3 thin films, depth profile studies using X-ray photoelectron spectroscopy (XPS) was done. Nearly stoichiometric was observed for both annealed and as-deposited films in inner and surface layers.

Short-Term Scheduling of Combined Cycle Units Using Mixed Integer Linear Programming Solution

Combined cycle plants (CCs) are broadly used all over the world. The inclusion of CCs into the optimal resource scheduling causes difficulties because they can be operated in different operating configuration modes based on the number of combustion and steam turbines. In this paper a model CCs based on a mixed integer linear programming approach to be included into an optimal short term resource optimization problem is presented. The proposed method allows modeling of CCs in different modes of operation taking into account the non convex operating costs for the different combined cycle mode of operation.

Design, Simulation &Optimization of 2D Photonic Crystal Power Splitter

A very compact (80 - 100 μm2) integrated power splitting devices with two outputs (1 × 2), four outputs (1 × 4) and six outputs (1 × 6) channel has been designed, simulated and optimized for Telecommunication purpose with T-Junction, Y-Junction, PC line defect waveguides integrated with multimode interference block (PCLD-MMI) and multiple line defect PC waveguides (MLDPCW) configurations. The optical modeling of these proposed structures was investigated by finite difference time domain (FDTD) simulation. With the optimization of the parameters (Hole Radius, R = 0.128 μm, Input Diameter, D = 1.02 μm, Input wavelength, λ = 1.55 μm, Substrate Reflective Index, nsub = Si(1.52), Photonic Crystal Material, npcs = InAs(3.45), and Rectangular crystal structure), 1 × 2 for Y-Junction (100%), 1 × 4 for T-Junction (92.8%) and 1 × 6 configuration for MLDPCW (81%) show maximum power transmission.

Design of DSTATCOM Controller for Compensating Unbalances

In a three phase power system, the voltages at the generation side are in sinusoidal and equal in magnitude with 120? phase difference between the phases. However, at the load side voltages may become unbalanced due to unequal voltage magnitudes at the fundamental frequency, phase angle deviations or unequal distribution of single phase loads. The voltage unbalance is a major power quality issue, because a small unbalance in the phase voltages can cause a larger unbalance in the phase currents. A completely balanced three-phase three wire system contains only positive sequence components of voltage, current and impedance, whereas unbalanced system contains both positive and negative sequence components of voltages and currents. The negative sequence component of current in the unbalanced system increases the temperature and losses in the equipments. Hence, it is necessary to mitigate this problem by supplying the negative sequence current to the load at the load side and keep the source side balanced. This paper proposes the shunt connected, current injecting Distribution Static Synchronous Compensator (DSTATCOM) with appropriate controller to mitigate the unbalanced load current. The symmetrical components based Hysteresis Current Controller (HCC) is designed for DSTATCOM to diminish the unbalances in a three-phase three-wire system. The performance of the controller is studied by simulating the entire system in the MATLAB/Simulink environment. The DSTATCOM with HCC is found to be better than other controllers because it is suitable for compensating both balanced and unbalanced loads.

INFLUENCE OF BACKBONE RIGIDITY ON THE LIQUID CRYSTALLINITY OF MESOGEN-CONTAINING POLYACETYLENES

Two acetylene polymers containing cyanobiphenyl-based mesogens,poly { 10-[ （（4’- cyano-4-biphenylyl ） oxy ） carbonyl] - 1 -decyne } （PA8CN ）, which has a relativelyfiexible polyalkyne backbone, and poly {[4-（（（12-（（4’-cyano-4-biphenylyl）oxy）dodecyl）oxy）carbonyl） phenyl]-acetylene} （PB12CN）, which has a fairly rigid poly （phenylacetylene ）backbone, were synthesized using respectively WCl6 and [Rh（nbd）Cl]2 as the catalysts.PA8CN exhibits enantiotropic interdigitated smectic A phase (SAd) over a temperaturerange as wide as ca. 100℃, whereas PB12CN is non-mesomorphic, demonstrating thatthe backbone rigidity plays an important role in determining the liquid crystallinity of thepolyacetylenes.

Bandgap engineered novel g-C_3N_4/G/h-BN heterostructure for electronic applications

The effect of an external electric field on the bandgap is observed for two proposed heterostructures graphitic carbon nitride-graphene-hexagonal boron nitride(g-C_3N_4/G/h-BN) in hexagonal stack(AAA) and graphene-graphitic carbon nitridehexagonal boron nitride(G/g-C_3N_4/h-BN) in Bernal stack(ABA). Their inter-layer distance, binding energy and effective mass has also been calculated. The structure optimization has been done by density functional theory(DFT) with van der Waals corrections. The inter-layer distance, bandgap, binding energy and effective mass has been listed for these heterostructures and compared with that of bilayer graphene(BLG), graphene-hexagonal boron nitride(G/h-BN) hetero-bilayer, graphene-graphitic carbon nitride(G/g-C_3N_4) hetero-bilayer and graphitic carbon nitride-graphene-graphitic carbon nitride(g-C_3N_4/G/g-C_3N_4) heterostructure in Bernal and hexagonal stack. g-C_3N_4/G/h-BN is found to offer lower effective mass and larger bandgap opening among the considered heterostructures.

Impact of Ambient Temperature on Electricity Demand of Dhaka City of Bangladesh

Per capita electricity consumption of Bangladesh is 400 KWh. Of the total population of 160 million, only 40 percent has the access of using electricity. Dhaka city consumes about 40 - 45 percent of the total electricity generation of the country. This study reports the trend of electricity use in the Dhaka city with emphasis on the impact of changing temperature due to urbanization and weather change. Hourly data of electricity demand of Dhaka city and the temperature profile of the city for a period of thirty months have been used for this study. To relate weather data like temperature, humidity, wind speed, wind direction, atmospheric pressure, dew point and visibility etc. with electricity demand of the city about 16,508 data between 2011 and 2017 have been considered. A statistical regression has been done to establish a relation between them. From this study it is found that reduction of only 1&degC air temperature could save 81 MV of electricity consumption in Dhaka city. A time series forecast has been done to estimate probable temperature change and subsequent electricity consumption up to year 2020. From the study it has been established that the temperature dependence of electricity consumption in Dhaka city is about 75%.

Comparative Analysis on Antenna Balun and Feeding Techniques of Step Constant Tapered Slot Antenna

This paper represents the performance analysis of the different shapes of antenna balun and feeding techniques for step constant tapered slot antenna. This work also addresses the benefits of antenna balun (circular and rectangular) along with two types of feeding techniques (Microstrip line L-shape and Microstrip line I-shape). The performance of the antenna for each technique is thoroughly investigated using Computer Simulation Technology (CST) Microwave Studio software simulation under the resonant frequency of 5.9 GHz. Results demonstrate that the proposed model is an effective tool for improving antenna performance. Moreover, an extensive comparison has been carried out between the two different shapes, with and without antenna balun and between two feeding techniques focusing on return losses, gain, directivity, and voltage standing wave ratio (VSWR).

Parasitic Effects on the Performance of DC-DC SEPIC in Photovoltaic Maximum Power Point Tracking Applications

This paper presents an analysis of the effect of parasitic resistances on the performance of DC-DC Single Ended Pri- mary Inductor Converter (SEPIC) in photovoltaic maximum power point tracking (MPPT) applications. The energy storage elements incorporated in the SEPIC converter possess parasitic resistances. Although ideal components significantly simplifies model development, but neglecting the parasitic effects in models may sometimes lead to failure in predicting first scale stability and actual performance. Therefore, the effects of parasitics have been taken into consideration for improving the model accuracy, stability, robustness and dynamic performance analysis of the converter. Detail mathematical model of SEPIC converter including inductive parasitic has been developed. The performance of the converter in tracking MPP at different irradiance levels has been analyzed for variation in parasitic resistance. The converter efficiency has been found above 83% for insolation level of 600 W/m2 when the parasitic resistance in the energy storage element has been ignored. However, as the parasitic resistance of both of the inductor has increased to 1 ohm, a fraction of the power managed by the converter has dissipated;as a result the efficiency of the converter has reduced to 78% for the same insolation profile. Although the increasing value of the parasitic has assisted the converter to converge quickly to reach the maximum power point. Furthermore it has also been observed that the peak to peak load current ripple is reduced. The obtained simulation results have validated the competent of the MPPT converter model.

Optimum Sizing and Siting of an Embedded Solar Photovoltaic Generation: A Case Study of 33 kv Sub-Transmission Network at Tarkwa, Ghana

The interconnection of Solar PV to the Tarkwa Bulk Supply Point (BSP) has become necessary in order to provide additional capacity to meet the ever-increasing demand of Tarkwa and its environs during the day. The Solar PV Plant will support the Tarkwa BSP during the day. In this study, a grid impact analysis for the integration of Solar PV plant at three points of common coupling (PCC) at Tarkwa Bulk Supply Point’s (BSP) 33 kV network of the Electricity Company of Ghana was carried out. The three PCCs were Tarkwa BSP, Ghana Australia Gold (GAG) Substation and Darmang Substation. Simulations and detailed analysis were carried out with the use of CYME Software (Cyme 8.0 Rev 05). The Solar PV was integrated at varying penetration levels of 9 MWp, 11 MWp, 14 MWp, 16 MWp, 18 MWp, 20 MWp and 23 MWp (representing penetration levels of 40%, 50%, 60%, 70%, 80%, 90% and 100%, respectively) of the 2020 projected light demand of Tarkwa BSP 25.15 MVA network at an average power factor of 0.903. From the study, the optimum capacity of Solar PV power that could be connected is 9 MWp at an optimum inverter power factor of 0.94 lagging, and the GAG Substation was identified as the optimal location. The stiffness ratio at the optimal location was determined as 41.9, a figure which is far greater than the minimum standard value of 5, and gives an indication of very little voltage control problems in the operation of the proposed Solar PV interconnection. The integration of the optimum 9 MW Solar PV Plant to the Tarkwa network represents an additional 12.77% capacity, decreased the technical losses by 7.76%, and increased the voltage profile by 1.97%.

Fuzzy-Logic Based Speed Control of Induction Motor Considering Core Loss into Account

Rotor flux and torque of an induction motor (IM) are decoupled to obtain performance of DC motor. The decoupling strategy has been developed in terms of stator current components where the core loss is neglected. Many different controllers including fuzzy logic controller (FLC) with neglecting core loss have been designed to control the speed of induction motor. The outcome of investigation about the effect of core loss on indirect field oriented control (IFOC) has been concluded that the actual flux and torque are not reached to the reference flux and torque if core loss is neglected. Thus, the purpose of this paper is to propose a fuzzy logic speed controller of induction motor where flux and torque decoupling strategy is decoupled in terms of magnetizing current instead of stator current to alleviate the effects of core loss. The performances of proposed fuzzy-logic-based controller have been verified by computer simulation. The simulation of speed control of IM using PI and FLC are performed. The simulation study for high-performance control of IM drive shows the superiority of the proposed fuzzy logic controller over the conventional PI controller.