Gain Values Research Articles

Productive Performance and Carcass Characteristics of Broiler Chickens Fed on Diets with Different Protein, Energy Levels, and Essential Oils During the Warm Season in Dry Tropics

This study evaluated the productive performance and carcass traits of broiler chickens during the warm season in dry tropical conditions. Two hundred, 1-day-old chicks were used. Birds were fed on reduced (RED) and standard (STD) diets, and two essential oils (EOs) levels, 0 and 200 ppm. The RED diets were formulated with 10% less energy and 10% less protein than STD diets. In the starter phase, weight gain was greater (p < 0.01) in birds fed STD than birds fed RED. In the starter phase, productive variables were not affected (p ≥ 0.14) by EOs. In the finisher phase, greater feed intake (p = 0.02) and higher weight gain (p = 0.04) were observed in chickens on STD. Feed conversion ratio was similar (p = 0.97) for STD and RED. Throughout this study (1–42 d), greater feed intake (p = 0.02) and higher weight gain (p < 0.01) were found in chickens on STD. Feed conversion ratio was similar (p = 0.51) for STD and RED. Broiler chickens on EO-supplemented diets had better feed conversion (p ≥ 0.08). Hot carcass weight was greater (p < 0.01) in birds on STD. Greater yields of leg-thigh (p = 0.01), back (p = 0.01), and wings (p < 0.01) were observed in RED. Carcass yields, breast yield, pH, and meat temperature were not influenced (p ≥ 0.14) by nutrient concentrations in the diet. Carcass evaluations were not affected (p ≥ 0.11) by EOs. Body temperature was lower (p = 0.03) in birds receiving RED, however EOs had no effect (p ≥ 0.22) on body temperature. For the length of the study, at 20:00 h, broiler chickens fed on RED diets showed lower (p = 0.04) body temperatures. In conclusion, broiler chickens were under heat stress during the study, and body temperatures were reduced in chickens fed on RED diets or with EOs. Diet modification or EO-supplementation may improve feed conversion, though RED diets may have a negative effect on weight gain or carcass values.

A Novel Enhanced Fire Hawks Optimization Approach for Improving the Efficiency of Converter‐Based Controllers in Switched Reluctance Motors

ABSTRACTSwitched reluctance motors (SRMs) have gained popularity in various industrial applications due to their advantages, including structural simplicity, high reliability, low cost, and operational stability over a wide speed range without relying on rare‐earth permanent magnet materials. However, these motors exhibit drawbacks such as weak torque density, low efficiency, and significant torque ripple, particularly in high‐speed operation. An efficient converter‐based control approach is proposed to manage speed and torque variations in SRM motors, addressing these issues. A multilevel converter (MC) is introduced as a fundamental component. The novel multilevel converter (NMC) accommodates SRMs with varying numbers of phases and exhibits quick demagnetization and excitation behaviors, enabling independent operation of each phase even during conduction overlaps. Subsequently, an effective controller is developed for the SRM motor, combining proportional integral derivative (PID) control with enhanced fire hawks optimization (EFHO). The EFHO optimizes the PID gain values to enhance controller performance. The converter operation minimizes torque ripple and facilitates speed management. The EFHO technique is a fusion of fire hawks optimization (FHO) and the sine cosine algorithm (SCA). This amalgamation improves the updating process of FHO by incorporating SCA. The proposed methodology is implemented in MATLAB and evaluated through various metrics, including SRM motor current, voltage, speed, and torque, under electric vehicle (EV) load conditions. Performance comparisons are conducted with traditional optimization algorithms such as the whale optimization algorithm (WOA) and ant colony optimization (ACO). The results validate the effectiveness of the proposed methodology in achieving improved SRM motor control and performance.

Fixation of Tripotassium Citrate Flame Retardant Using a Sorbitol and Citric Acid Wood-Modification Treatment

Wood modification has been explored in various ways to enhance dimensional stability and reduce flammability, with a focus on environmentally friendly treatments to meet market demands. This study aimed to investigate the efficacy of new, potential fire-retardant materials. Specifically, the study examined the combination of tripotassium citrate (TPC), a water-soluble and bio-based fire retardant, with sorbitol and citric acid (SorCA), an eco-friendly thermosetting resin previously studied. While TPC is known to control combustion, its application in wood modification has not been thoroughly researched. To assess the fixation and flammability of these fire retardants, tests were conducted on Scots Pine (Pinus sylvestris L.), including chemical analysis, dimensional stability, mechanical properties, flame retardancy, and leaching tests. The combination of SorCA and TPC showed high weight percent gain (WPG) values; however, leaching and anti-swelling efficiency (ASE) tests revealed challenges in fixation stability. The dynamic mechanical properties were reduced, whereas the static strength values were in the same range compared with untreated wood. While TPC exhibited high flame retardancy prior to leaching, its efficacy diminished post-leaching, underscoring challenges in fixation and the need for improved retention strategies. Bunsen burner tests conducted on leached specimens indicated enhanced performance even under severe leaching conditions as per the EN 84:2020 procedure. However, cone calorimetry measurements showed less favorable outcomes, emphasizing the necessity for further investigation into optimizing TPC retention and enhancing treatment efficacy.

Thresholds for the value judgement of health technologies in the United Arab Emirates: a consensus approach through voting sessions

BackgroundIn the evolving healthcare landscape of the United Arab Emirates (UAE), establishing cost-effectiveness thresholds (CETs) is pivotal to informing decision-makers about the value of health technologies.ObjectiveThis study aimed to establish...

Flexible Impedance Matching in a Self‐Diplexing Patch Antenna

ABSTRACTThis study introduces a new approach to achieve flexible impedance matching in a self‐diplexing conventional patch antenna by using paired vias for impedance bandwidth tunability. The antenna design incorporates a rectangular radiating patch, an orthogonal arrangement of a couple of paired vias, and a bottom ground plane. The patch is excited with the help of two orthogonal microstrip feeds aligned along the centerline of the broadside and narrow sides of the patch. The orthogonal vias set enables dynamic impedance matching in two frequency bands, lower and upper ranging from 2 to 3 GHz. Optimized via placement achieves high decoupling between input ports, facilitating the self‐diplexing phenomenon. To validate the proposed concept, a prototype with patch dimensions of has been analyzed, fabricated, and subjected to comprehensive experimental study. The experimental results demonstrate the successful realization of two distinct operating frequency bands, centered around 2.47 and 2.66 GHz, each exhibiting peak gain values of 5.75 and 6.31 dBi, respectively. The input port isolation values are noteworthy, measuring at −34B and −29.5 dB for lower and upper operating frequency bands, respectively. The design offers a low‐profile, minimally coupled structure with independent band control and the unique ability to simultaneously transmit and receive signals.

Determination of converter parameters for high-voltage electromechanical systems of stationary installations of industrial fans

Purpose. To study the electromagnetic processes in the circuit of the phase rotor of a high-voltage induction motor connected to the network through a step-up converter, to determine the parameters of the converter and their relationship with the voltage gain to ensure the optimal level of energy efficiency of the electromechanical system. Methodology. Methods of theoretical electrical engineering for the construction of a rotor circuit replacement scheme for an induction motor with a step-up converter, methods for solving a system of first-order differential equations, analytical methods. Findings. The expediency of using a converter that combines the rotor circuit of a high-voltage induction motor with the power supply network and provides regulation of the rotor EMF with the recovery of the slip energy of the induction motor rotor to the power supply network has been proved. This will ensure speed control of powerful high-voltage induction motors on the rotor side with an EMF of up to 600 V and significantly reduce the cost of a high-voltage electromechanical system. A methodology for determining the converter gain and the parameters of the rotor circuit of the electromechanical system is proposed, which allows determining the transformation ratio of the matching transformer at the optimal value of the voltage gain. The conditions of trouble-free operation of the inverter at the moment of start-up of the electromechanical system are determined. Achieving these conditions is ensured by determining the delay of the control signal to the power keys of the inverter of a step-up converter. The correlation between the voltage gain and the equivalent resistance of the rotor circuit of the electromechanical system is established. Originality. The ratio of the voltage gain to the equivalent resistance of the rotor circuit of the electromechanical system is established, which will ensure the matching of the rotor EMF with the voltage of the power supply network while maintaining a high level of energy efficiency. Practical value. A methodology for determining the gain and parameters of a step-up converter is proposed, which allows determining the transformation ratio of a matching transformer at the optimal value of the voltage gain. The proposed methodology can be applied to the modelling of complex powerful high-voltage electromechanical systems, especially for stationary installations of industrial fans.

The Growth Performance, Haematological Parameters and Serum Biochemistry of the Flathead Grey Mullet Mugil cephalus Under Recirculating Aquaculture System and Traditional Culture Systems.

The present investigation explored the growth performance, haematological parameters and serum biochemistry of flathead grey mullet under recirculating aquaculture system (RAS) and traditional culture systems. Nine hundred healthy fish, weighing 43.80 ± 3.55 g and length 16.54 ± 0.82 cm were randomly distributed to three treatments of RAS and traditional culture systems (T1: 20% of water changed daily; T2: once-through system 250 L/h; T3: RAS-20% of water changed weekly) in nine concrete tanks of 4000 L at stocking density of 100 fish/tank and each treatment had three replicates. Fish were fed (33.1% crude protein, 3 mm pellets) twice a day at a rate of 3% for 12 weeks. These findings suggest that the T3 followed by T2 led to notable improvements in growth performance compared to other culture systems. Significantly elevated values of weight gain, length gain, specific growth rate, average daily gain and survival % were observed in T3. The RBCs exhibited a significant decrease under T2. Haemoglobin concentrations and WBC counts significantly increased under RAS. Significant values of mean cell haemoglobin and mean cell haemoglobin concentration were recorded in T2. Total protein, albumin and globulin enhanced significantly under RAS, whereas the highest values of cortisol were observed in T2 and T3. These findings demonstrate that the RAS followed by once-through system significantly improve growth performance, feed efficiency and survival, as well as enhancing the haematology and serum biochemical status of flathead grey mullet. In conclusion, RAS provides ideal conditions for optimizing physiological functions, growth performance and fish health.

Semi-active vibration control via a magnetorheological damper and active disturbance rejection control

This work provides an alternative for the semi-active vibration control problem via state feedback plus an active disturbance rejection control (K-ADRC) for a multistory building structure equipped with one magnetorheological damper (MRD) located between the ground and the first story. This control law introduces a disturbance observer (DOB) to estimate the total disturbance in real time, produced by the earthquake perturbation, unmodeled dynamics, and parametric uncertainties, and then cancel their effect using a part of the control signal. Moreover, using a diffeomorphism, the K-ADRC provides a proportional derivative (PD) controller designed to improve internal stability. A prominent feature of the active disturbance rejection control (ADRC) algorithm is that the value of the DOB gain is selected according to the system bandwidth. The stability of the system is verified via Lyapunov analysis. Moreover, the building structure model and the MRD are accomplished by incorporating a nonlinearity state that represents the hysteresis effect to perform real behavior in addition to assuming that acceleration is the only available measurement of building structures. Thus, integral filters are provided based on the appropriate cut-off frequency to estimate displacement and velocity, avoiding bias, offset, and phase shifts. Experimental results from a reduced-scale two-story building prototype demonstrate that the proposed K-ADRC is promising for real applications, and it has better performance than the state feedback (K) and the linear quadratic regulator (LQR) control techniques.

MrFeed Pro50 FF supplementation improves growth of Largemouth Bass fed a diet containing 160‐g/kg fish meal

AbstractObjectiveThis study aimed at evaluating the role of a novel commercial product, MrFeed Pro50 FF (MP50), as a functional ingredient with which to formulate low‐fish‐meal diets for Largemouth Bass Micropterus nigricans.MethodsSeven test diets were examined. A reference diet (RD) contained 400‐g/kg fish meal, and a control diet (C) was formulated by replacing 60% of the fish meal in RD with poultry by‐product meal. The other five diets were formulated by adding MP50 to C at 5.0 (D50), 7.5 (D75), 10.0 (D100), 12.5 (D125), or 15.0 (D150) g/kg. Fish (initial body weight = 9.2 ± 0.1 g) were fed the test diets for 8 weeks.ResultThe MP50 supplementation level significantly affected weight gain, final body weight, carbon retention efficiency, energy retention efficiency (ERE), hepatosomatic index (HSI), viscerosomatic index (VSI), the ratio of fish meal consumption to fish production (RCP), and carbon waste. The weight gain of fish fed D50, D75, and D100 was greater than that of fish fed C and D150. The ERE was greater in fish fed D50 and D100 than in fish fed C and D75. The HSI and VSI were greater and nitrogen and carbon wastes were lower for fish fed D50 and D100 than in fish fed C. Fish fed D50, D75, and D100 exhibited greater weight gain and lower RCP values compared with fish fed RD. The weight gain of fish fed RD did not significantly differ from the weight gain of fish fed C, D125, and D150, confirming that the minimum fish meal level could be reduced to 160 g/kg.ConclusionThis study indicates that MP50 at 5.0–10.0 g/kg can be used as a functional ingredient in low‐fish‐meal diets for Largemouth Bass.

Effectiveness of Digital Literacy Learning Model with Video Content Project In Enhancing Sustainable (SDG) Civic Intelligence

Objective: This study aims to find the effectiveness of a newly developed learning model, namely a digital literacy model with a video content project in improving citizenship intelligence, as an effort for sustainable development goals. Theoretical Framework: The theoretical framework is drawn from the utilization of digital technology and social media in learning practices. However, the utilization of digital technology does not show good digital literacy, the learning outcomes have not had an optimal impact, especially in improving citizenship intelligence. Method: The approach used in this study is a quantitative approach, quasi-experimental method. Sampling was sorted purposively, the experimental and control classes totaled 140 people from six classes, all classes used as research samples came from Mandiri University, Subang University, and Subang State Polytechnic. Data collection techniques were carried out with pre-post tests and questionnaires. Results and Discussion: The results of the study based on the pre-post test gain test showed that the experimental class got a gain value of 0.71 which was in the high criteria, this value was much different from the control class which got a gain value of -0.04 which was in the low criteria. Therefore, the digital literacy learning model with video content projects proved to be effective in increasing Civic Intelligence, compared to the conventional exploratory model with lecture and question and answer methods. Research Implications: This research has implications for the development of learning theory, because this model itself is the result of innovation from the philosophy of constructivism learning and cybernetic learning theory. Originality/Value: Practically, the results of this study are useful in improving the quality of learning practices, this model can be used by lecturers and students to achieve learning objectives.

Study on Mass Transfer and Physicochemical Properties of Avocado During Osmotic Dehydration

A previous study found that mass transfer occurring during the osmotic dehydration (OD) process. This phenomena is possible causing modification in physicochemical properties; therefore, understanding the OD effect on quality attributes is important. This research aimed to study the impact of sucrose concentration and immersion time on the kinetics of mass transfer and the physicochemical properties of avocado (Persea americana var. Miki) during the OD process. The samples were immersed in a sucrose solution (45, 55 and 65 ° Brix) for up to 300 min, then the mass transfer parameter and physicochemical properties were evaluated. The results showed that the highest rate of water removal (WR) was –0.037 g.g–1.h–1 using the 55 ° Brix solution, which also led to an increase in the soluble solid gain (SSG) value to 0.0126 g.g–1.h–1, while the highest WR/SSG ratio was obtained after 180 min of immersion using 65 ° Brix (2.451). A 2nd-order polynomial model accurately describes avocado mass transfer kinetics and their relationship to physicochemical properties. The model showed the best adjustment for WR, SSG, and weight loss (WL), as pointed out by R2 = 0.9671, 0.8968 and 0.9573, respectively. WR has a negative effect on firmness (R2 = 0.9278), vitamin C (R2 = 0.9349), and total fat (R2 = 0.8954). The uptake of sucrose correlated with decrease of vitamin C (R2 = 0.9391), whereas WL also affected the loss of total fat (R2 = 0.8288). The OD process modified the chroma of the avocado by reducing lightness, increasing greenness and yellowness, and yet protecting the flesh from the browning effect. Overall, this study provides insights into the relationship between mass transfer and physicochemical properties, and it is useful to predict the final condition of the osmo-avocado before subsequent processes. HIGHLIGHTS Immersing the avocado in a 55 ° Brix solution resulted in the highest rate of water removal (WR) and soluble solid gain (SSG). The highest ratio of WR and soluble solid gain (WR/SSG) was obtained at 180 min of immersion using a 65 ° Brix solution. The 2nd-order polynomial model fits the mass transfer parameters (WR, SSG, and weight loss/WL). WR contributed to a softened texture, color contrast, degradation of vitamin C, and total fat content. The combination of mass transfer and physicochemical property models is useful for designing the OD process and predicting the final condition of osmo-avocado. GRAPHICAL ABSTRACT

Deep Learning Method of Precious Wood Image Classification Based on Microscopic Computed Tomography

Correctly identifying precious wood species is crucial for import and export trade and furniture material identification. This study utilizes nondestructive testing (Microscopic Computed Tomography, Micro-CT) to capture microscopic images of the transverse, radial, and tangential sections of 24 precious wood species, creating a comprehensive dataset. The SLConNet deep learning model is developed, enhancing recognition accuracy through multi-scale convolution and an improved residual block structure. The experiment results show that the classification accuracy of the transverse, radial and tangential sections is 98.72, 96.75 and 95.36 % respectively when the gain value is 0.8. The model outperforms traditional models like Alexnet, ResNet50, Inception-V3, and Xception. This research highlights the efficiency of nondestructive testing in obtaining a large number of microscopic wood images, compared to traditional anatomical methods. The SLConNet model showcases high accuracy in precision, recall, and specificity, suggesting its potential for widespread applications in wood classification.

Design of a Compact, Planar, Wideband, Overlapped, Bow-Tie Antenna in a Single Layer with Stable Bi-Directional Radiation Patterns

In this paper, a planar, bow-tie antenna with an enhanced bandwidth and a bi-directional radiation pattern is proposed. The concept of multi-resonance is applied by implementing the superposition of three different bow-tie components with various radii and flare angles in an overlapped fashion into a single element, resulting in a significant increase in bandwidth. The antenna has an electrical size, kr, of 1.10, calculated at the lowest frequency of operation. The proposed antenna is simulated, and a prototype is fabricated for verification by measurement. The result is a wide −10 dB bandwidth of 80.3% (1.23–2.88 GHz) from the measurements. The antenna also maintains a bi-directional radiation pattern, with a negligible difference between the forward and backward realized gains, within the entire −10 dB bandwidth. The measured realized gain values in the forward and backward directions are between 1.5 dBi and 3.7 dBi over the −10 dB bandwidth. The comparison of the measurement and simulation results shows good agreement.

Nonlinear integral backstepping control based on particle swarm optimization for a grid-connected variable wind energy conversion system during voltage dips

Double-fed induction generator (DFIG) wind turbines connected to the grid are particularly subject to grid problems such as voltage dips. Because of this, it might be challenging to maintain system stability and prevent system disconnections when using a Proportional-Integral (PI) Controller to operate this system. This paper applies the Integral Backstepping Control for the wind power plant system connected to the power grid. The Integral Backstepping is a nonlinear and recursive method that employs the Lyapunov theory to ensure the system's stability. The best selection of gain values for the Lyapunov function guarantees improved system control. These gains are frequently adjusted using the trial-and-error strategy, which is time-consuming and inefficient. This technique becomes more complex when many parameters need to be determined. It also limits the system's performance and restricts this nonlinear approach's advantages. The objective is to apply the particle swarm optimization for computing several constant values of the nonlinear approach by minimizing an integral absolute error criterion index. The weighted sum of errors is employed to solve the multiple objective problems. The proposed controller tracks the maximum power point, maintains the voltage of the DC-Link constant, and controls active and reactive power. The robustness of this method is verified in critical conditions, including system parameter variation and asymmetrical and symmetrical grid faults. The simulation findings highlight the effectiveness and robustness of the combination of Integral Backstepping with Particle Swarm Optimization in terms of reducing response time from 10.6 (ms) to 2 (ms), canceling static error, and improving overshoot compared to the vector control based on PI regulator. Besides, the DC-Link voltage ripples during the asymmetrical grid faults are reduced to ±1 (V) using the suggested controller. The latter can be implemented thanks to advancements in Central Processor Unit technology.

Effects of Dietary Microalgae Schizochytrium sp. Supplementation on Growth Performance and Skin Color in Jack Dempsey cichlid (Rocio octofasciata)

Growth retardation and decreased vivid coloration are significant issues in the ornamental fish market, particularly among cichlids. This study investigates the effects of Schizochytrium sp. microalgae supplementation on the growth and skin coloration of the Jack Dempsey cichlid (Rocio octofasciata). Three experimental groups were established: a control group (C) with no supplementation, and two microalgae-supplemented groups with 0.5% (S05) and 1% (S10). The control group was fed a commercial diet, while the S05 and S10 groups received the microalgae mixed with the commercial feed via spraying. A total of 135 Jack Dempsey fish (mean initial weight: 1.17 ± 0.14 g) were stocked into nine glass tanks (100 L each), with three replicates per group. After a 60-day feeding trial, growth indices revealed significant differences (p<0.05) between the control and algae-supplemented groups. The S10 group exhibited the highest final weight (FW) and the lowest feed conversion ratio (FCR). Additionally, the weight gain (WG) and specific growth rate (SGR) values for the S10 group were significantly higher than those of both the control and S05 groups (p<0.05). However, skin color parameters, including L* (brightness), a* (+red/-green axis), b* (+yellow/-blue axis), chroma (Ch), and hue angle (Hue), showed no statistical differences among the groups. This study demonstrates that a diet supplemented with 1% Schizochytrium sp. can enhance growth parameters and serve as a beneficial feed additive for Jack Dempsey cichlids.

Does the Receiver Type Used in Receiver-in-Canal Hearing Aids Have an Effect on Real-Ear-to-Coupler Difference and Coupler Response for Flat Insertion Gain Values?

Background and Aim: Real-Ear-to-Coupler Difference (RECD) is affected by the type of transducer and its coupling method. This study aimed to investigate the effect of receiver type used in Receiver-in-Canal (RIC) hearing aids on RECD and Coupler Response for Flat Insertion Gain (CORFIG) obtained by the same coupling method. Methods: In this study, the right ears of 30 normal-hearing adults (25 men and 5 women, with a mean age of 28.13±5.62 years) were studied. We used the RIC hearing aids with two standard and power receivers. The foam of the ER-3A insert earphone was used as a coupling system in both receivers. By using the Audiogram Direct test within Phonak’s fitting software, 70 dB HL intensity was produced at different frequencies, once in the real- ear and again in the HA-1 coupler. By assessing the difference between real-ear and HA-1 coupler measurements, the RECD was first obtained. Then, the CORFIG was obtained at different frequencies by subtracting the Microphone Location Effect (MLE) and RECD from Real-Ear Unaided Gain (REUG). Results: The RECD and CORFIG values obtained from the standard receiver at all frequencies were significantly different from those from the power receiver (p<0.05), where the use of the power receiver resulted in lower RECD and higher CORFIG. With the increase in frequency, the RECD increased. A small frequency changes of 50 Hz had a significant effect on RECD and CORFIG. Conclusion: The type of receiver used in RIC hearing aids has a significant effect on the RECD and CORFIG values. Keywords: Real-ear measurement; real-ear-to-coupler difference; insertion gain; hearing aid

The effect of mind mapping on the level of student learning success in the Pancasila course: a study on students of the UNY English department

The quality of a nation's human resources can be measured from the learning achievements of students. Learning achievement is an indicator of student learning success and also an indicator of educator success in conducting learning. Learning success reflects the success of students in mastering learning concepts expressed by grades. One way to increase student understanding of concepts is by applying mind mapping. This study aims to determine the effect of mind mapping on the success rate of student learning in the Pancasila course. The method used in this research is Pre-Experimental with One Group Pretest-Posttest Design. The research sample consisted of 36 students majoring in English literature at UNY by choosing purposive sampling. Analysis of the learning outcomes obtained shows that the value of ha is accepted which means that the effect of applying mind mapping has on student learning success in the Pancasila course. While the Gain value (the average increase as an indicator of learning success) obtained results of 0.33 in the medium category. The implication of this research is as a source of information or a reference for educators that the application of mind mapping in learning can increase learning success.

Dual band high gain circularly polarized frequency tunable silicon-graphene based MIMO antenna for THz wireless applications

Abstract The two-port aperture linked silicon-graphene radiator in THz regime is investigated in this study. The primary characteristics of the radiator design are as follows: (i) a perturbed circular aperture that offers two working spectrums, 2.85-3.58 THz and 2.31-2.45 THz, with the support of a circular E-field within the two operating bands; (ii) an aperture mirror arrangement that enhances polarization diversity and raises the isolation level to over 25 dB; and (iii) a graphene layer over the ceramic that allows for tunability in the entire working band as well as a circularly polarized frequency range. The broadsided radiation pattern is produced by the dual hybrid mode, or HEM11δ and HEM12δ. A metallic reflector positioned underneath the radiator enhances the dual working spectrum's gain value, or around 7.5 dBi. With the aid of CST-MWS software, the final results are confirmed. The developed radiator may be used for a variety of wireless applications in the THz domain thanks to its stable far-field pattern and strong diversity parameter values.

Real-time monitoring and control of a PV-fed enhanced cubic voltage gain converter for DC microgrid

In this manuscript, a novel high-gain DC-DC converter with an ultra-step-up voltage gain value of 22.2 is introduced along with a custom-developed web application for remotely monitoring and controlling the power converter. The proposed converter is synthesized using two stages – stage 1 yields a cubic voltage gain and stage employs a diode-capacitor gain cell (DCGC) to reduce the voltage stress on the switch. The proposed gain extension hypothesis is experimentally validated through an 18 V to 400 V, 175 W prototype converter which delivers 175 W to the load at a 93.5% efficiency. The proposed converter exhibits excellent dynamic response when regulating the output voltage to 400 V over a wide range of input voltage and load current variations; the overshoots and undershoots are also negligible. Further, the maximum voltage stress on the switch is only 37.5% of the output voltage. For remotely controlling and monitoring the converter under real-time conditions with a high sampling rate, a web application is developed using React.js. The STM32 microcontroller is programmed to transmit data serially to the server, which then interacts with the web application using hypertext transfer protocol (HTTP) and WebSockets. The effectiveness of the developed interface is also practically verified by controlling the proposed converter in various modes viz., open-loop, soft-start, constant voltage, constant current, soft-stop, load regulation and overvoltage protection modes. Based on the comparison with several converters the proposed converter possesses unique advantages. Additionally, its web-based remote monitoring and control features are preferable for DC microgrid application.

High-Gain Multi-Band Koch Fractal FSS Antenna for Sub-6 GHz Applications

This study introduces a novel antenna based on the binary operation of a modified circular patch in conjunction with the Koch fractal. The antenna is intended for applications in the sub-6 GHz band, partial C-band, and X-band. The low-cost antenna is fabricated on a 1.6-mm-thick FR-4 substrate. A frequency-selective surface (FSS) is used to overcome the decreased values of the gain and bandwidth due to the fractal operations. The introduced split ring resonator (SRR) and the antenna substrate dimension reduction reduce the bandwidth and antenna gain. The air gap between the FSS and the antenna not only enhances the antenna gain but also controls the frequency tuning at the design frequency. The antenna size is miniaturized to 36.67%. A monopole antenna ground loaded with an SRR results in improved closest tuning (3.44 GHz) near the design frequency. The antenna achieves a peak gain of 9.37 dBi in this band. The FSS-based antenna results in a 4.65 dBi improvement in the gain value with the FSS. The measured and simulated plots exhibit an excellent match with each other in all three frequency bands at 2.96–4.72 GHz. These bands cover Wi-MAX (3.5 GHz), sub-6 GHz n77 (3300–3800 MHz), n78 (3300–4200 MHz), and approximately n79 (4400–4990 MHz), in addition to C-band applications.