Simple Design Research Articles

ANALYSIS OF LOAD ON PERMANENT MAGNET SYNCHRONOUS GENERATOR (PMSG) 12S8P WITH SPEED VARIATION

Abstract. This study investigates the impact of speed variation on the performance of a Permanent Magnet Synchronous Generator (PMSG) configured with 12 slots and 8 poles (12S8P) for wind energy conversion systems. PMSG has gained attention due to its high efficiency, simple design, and ability to operate effectively at low speeds, making it particularly suitable for renewable energy applications like wind turbines. Using MagNet simulation software, the performance of the PMSG was analyzed over a speed range of 1000–6000 rpm and load variations of 10–50 ohms. The results showed a maximum magnetic flux of 0.000927 Wb, while the no-load average voltage was 17.78 V at a speed of 1000 rpm. Furthermore, it was observed that voltage and current increased proportionally with speed. Optimal torque performance was achieved at a 30-ohm load at a speed of 5000 rpm, highlighting the importance of load optimization for effective energy conversion. Efficiency analysis revealed that the generator achieved its highest efficiency of 92.96% at a 10-ohm load and a speed of 5000 rpm. This study also emphasizes the influence of material properties, slot-pole design, and load conditions on generator performance. These findings provide critical insights for the design and optimization of wind turbines, particularly in regions with varying wind speeds. Moreover, this research contributes to advancing the utilization of renewable energy technologies by offering data-driven strategies for enhancing system efficiency and reliability..

Learning to read and interpret tattoos.

Tattooing has been a facet of many civilizations and cultures for millennia with a recent resurgence in popularity in many Western countries. The reasons for tattooing are diverse ranging from simple decorative designs to enforced tattooing of concentration camp inmates. In a forensic context tattoos are frequently observed and may play a role in some cases of identification, even after decomposition, incineration or dismemberment. More broadly however, tattoos can provide significant information on a decedent's name and age, country or region of origin, religion, names of family members and friends, pet ownership, political affiliations, sporting and recreational activities, military service, gang memberships, drug usage and medical data. Thus, careful reading of tattoos at the time of post mortem examination can sometimes be a very productive exercise delivering background material on a decedent that may not have been provided in police reports.

Unravelling the nonlinear generation of designer vortices with dielectric metasurfaces

Vortex beams are currently drawing a great deal of interest, from fundamental research to several promising applications. While their generation in bulky optical devices limits their use in integrated complex systems, metasurfaces have recently proven successful in creating optical vortices, especially in the linear regime. In the nonlinear domain, of strategic importance for the future of classical and quantum information, to date orbital angular momentum has only been created in qualitative ways, without discussing discrepancies between design and experimental results. Here, we demonstrate and analyze the generation of high-purity second harmonic (SH) optical vortices via dielectric meta-holograms. Through full-wave simulations and a proper fabrication protocol, we achieve efficient frequency doubling of an unstructured pump beam into SH vortices with topological charges from 1 to 10. Interferometric and modal-purity measurements confirm the generation of high-quality SH vortices with minimal deviations from the intended design thanks to a quasi-local control over the SH phase. Through systematic comparisons between experimental data and semi-analytical calculations, we also provide a clear insight into the occurrence of ghost vortices in the metasurface-generated harmonic beams, highlighting the importance of simple designs that can be readily transposed into fabricated devices with high fidelity. Our findings underscore the potential of nonlinear dielectric metasurfaces for versatile structured-light generation and manipulation, paving the way for future developments in integrated photonic systems.

Studies on Thermal Separation and the Effects of Geometrical and Operating Parameters on the Performance of Pressure Wave Refrigerators

Abstract Thermal separation in a pressure wave refrigerator (PWR) occurs primarily through the propagation of shock waves and reverse-moving rarefied waves produced by injecting a high-pressure gas into a low-pressure residual gas in a receiving tube or channel. The major advantages of PWRs are simple design, low cost, high reliability, low rotational speed, and efficiency comparable to the conventional turbo-expanders. The objectives of this work are to understand the thermal separation in PWRs and to study the effects of various geometrical and operating parameters on the performance of PWRs. Two-dimensional computational fluid dynamics (CFD) simulation using a finite volume method is adopted for this study. The results indicate that the temperature and pressure profiles of the fluid inside the receiving tube just before the discharge, in the region about half the tube length from the inlet nozzle, strongly govern the performance of a PWR. The operating frequency at which the isentropic efficiency attains the first peak value is determined in a generalized way. Within the chosen geometrical and operating parameters, the optimized tube length, operating frequency, and pressure ratio are 2 m, 50 Hz, and 2.5, respectively. The findings in this article will be useful in designing and operating PWRs optimally.

Magnetofluidic-Assisted Portable Automated Microfluidic Devices for Protein Detection.

To facilitate on-site detection by nonspecialists, there is a demand for the development of portable "sample-to-answer" devices capable of executing all procedures in an automated or easy-to-operate manner. Here, we developed an automated detection device that integrated a magnetofluidic manipulation system and a signal acquisition system. Both systems were controllable via a smartphone. In the device, the mixing of solutions and magnetic beads in the static chamber was enhanced by steel bead agitation, which improved the reaction efficiency. We demonstrate the performance of the device using myoglobin detection as an example. During the detection process, the plasma was separated from the whole blood sample using a homemade mini-centrifuge, and subsequently, the plasma, magnetic beads, and reagents were added to a magnetofluidic chip with multiple chambers. After the chip was loaded, the device was initiated with a smartphone App via Bluetooth. Then, the magnetic beads were shuttled through different chambers of the chip and multiple steps were completed automatically: first, the targets were separated and enriched using antibody-modified magnetic beads, followed by washing, binding with aptamer-functionalized G-quadruplex, signal amplifying (optional), and chromogenic reaction. Finally, the images of colored solutions were captured and processed by a smartphone to obtain the concentrations of myoglobin. The detection limits depended on the mode of signal conversion, which were 0.1 or 2.7 nM (with or without signal amplifying). With its simple operation, compact design, low cost, and ease of scalability, this automated detection device holds potential applications in human health, food safety, environmental monitoring, etc.

Investigator-Initiated Clinical Pharmacokinetic Studies in Resource-Limited Settings: Minimal Requirements and Practical Guidance.

Clinical pharmacology studies are critical for determining the efficacy and safety of drugs. Due to the resource-intensive nature of these studies, most have been conducted in high-income countries, leading to a significant gap in clinical pharmacology data for patients in low- and middle-income countries. This paper provides an overview of the minimal requirements for performing a clinical pharmacology investigator-initiated trial (IIT), including pharmacokinetic sampling. We identify common challenges in resource-limited settings and propose strategies to overcome them. This guideline covers regulatory approval, participant recruitment, drug storage, sample collection and handling, transport, bioanalytical analysis, and data management tailored to the constraints of resource-limited settings. Strategies are proposed to minimize resource demands, including simplified study designs, the use of technologies like whole blood microsampling, and opportunities for collaboration. The goal is to provide practical guidance for those seeking to perform a clinical pharmacology IIT in resource-limited settings to improve safe and effective drug treatment for patients worldwide. Beyond the scope of this guideline is a detailed step-by-step guide on how to perform clinical pharmacology studies.

Adult-plant resistance and a suitable method of reaction determination to scald and net form net blotch in malt barley genotypes at a hot spot location in Ethiopia

Scald and net form net blotch caused by fungal pathogens Rhynchosporium secalis and Pyrenophora teres f. teres, respectively, are significant foliar diseases affecting barley production on a global scale, and they lead to substantial reductions in both yield and quality. In the current study, the reactions of 100 malt barley genotypes to the diseases were evaluated under natural conditions in Ethiopia. Again, several methods of genotype reaction determination were assessed to select a suitable method. Field trial was conducted using a simple lattice design. The grain yield of ten middle rows (5 m2) was evaluated, and the results were converted to t ha−1. The relationship between independent and dependent variables was analyzed using the Pearson correlation in ellipses predictor at a P-value of 0.05 and 0.01. Logistic and Gompertz models were used for disease rate analysis. Genotypes HB#P786 and HB#P875 scored the highest (4.7 t ha−1) and lowest (0.8 t ha−1) grain yield, respectively. Eyal classes and Eyal and Brown reaction types were selected from several methods of genotype reaction determination. Out of one hundred genotypes evaluated, 41% were susceptible, 52% were moderately susceptible, 5% were moderately resistant, and 2% were resistant to scald disease. Genotypes such as HB#P1063 and HB#P239 were resistant to scald disease. Moreover, 16% were susceptible, 68% moderately susceptible, 12% were moderately resistant, and 4% were resistant to net form net blotch disease. Genotypes such as HB#P1063, HB#P239, SARC#41, and HB#P793 were resistant to net form net blotch disease. Therefore, these genotypes can be used for crop improvement in subsequent breeding schemes. A negative correlation (r = − 0.1) between plant height and leaf blotch severity indicated that the highest plant height genotype could be used for scald resistance. The current research suggests that the breeder can use the identified resistant and moderately resistant genotypes for future breeding schemes.

How to Run Linear Mixed Effects Analysis for Pairwise Comparisons? A Tutorial and a Proposal for the Calculation of Standardized Effect Sizes.

This tutorial provides guidelines for conducting linear mixed effects (LME) analyses for simple designs, aimed at researchers familiar with t-tests, analysis of variance (ANOVA) and linear regression. First, we compare LME analyses with traditional methods when participants are the only source of random variation. We show that LME analysis is more interesting as soon as you have more than one observation per participant per condition. The second section discusses studies where both participants and stimuli are used as sources of random variation, ensuring robust generalization beyond the specific stimuli tested. In our search for standardized effect sizes, we saw that partial eta squared is even less informative for LME than for ANOVA. We present eta squared within as an alternative, to be used in combination with the traditional measure eta squared (also in ANOVA). To facilitate implementation, we analyze toy datasets with R and jamovi. This tutorial gives researchers a good foundation for LME analyses of simple 2 × 2 designs and paves the way for tackling more complicated designs.

Implementasi Software-Defined Network Terintegrasi Firewall pada Proxmox untuk Pengontrolan Konfigurasi Jaringan dan Pengamanan Layanan Container

Virtualization technology has helped companies consolidate various server roles into a single physical server, reducing hardware costs. Hypervisor is a software in virtualization that is used to manage server hardware, allowing multiple Virtual Machines (VM)/Containers (CT) to run on a single physical machine. Companies face various challenges to remain competitive in the digital era, such as the need for rapid deployment of virtual guests and virtual networks on hypervisors in development, testing, and production environments, as well as securing network services. The purpose of this study is to implement SDN on hypervisors to centrally control virtual network configurations with a simple design, reducing setup and maintenance costs and time. In addition, it also implements a firewall and Virtual Private Network (VPN) based on OpenVPN and a reverse proxy to secure the hypervisor and VM/CT so that services remain available. This study presents a new approach that integrates Software-Defined Network (SDN)-based network management with comprehensive security solutions on hypervisors. This approach combines efficiency in network management and security that have rarely been focused on simultaneously in previous studies. The research method uses the Network Development Life Cycle (NDLC). The hypervisor used is Proxmox Virtual Environment (PVE) which is installed on the Virtual Private Server (VPS) provider IDCloudHost. Based on the results of the trials that have been carried out, it can be concluded that the simple zone type SDN on PVE can be used to control network configurations centrally and more simply such as routing, Dynamic Host Configuration Protocol (DHCP), Source Network Address Translation (SNAT), hostname registration and Internet Protocol (IP) from CT to forward lookup zone on the Domain Name System (DNS) server. Activating the firewall and creating rules at the cluster and CT levels from PVE and OpenVPN can protect the infrastructure when accessed both internally and externally. While the implementation of nginx reverse proxy can secure access to HTTP/HTTPS services on CT in PVE.

STRUCTURAL DESIGN OF CONCRETE PAVEMENTS WITH LEAN CONCRETE LOWER COURSE

A procedure is presented for the structural design of concrete pavements incorporating a lower layer of lean concrete, either as a subbase constructed separately or as a lower layer in monolithic construction. An analysis of flexural stresses is used to recognize the strength and elastic properties of the materials and the layer thicknesses. Modifications of conventional linear elastic theory are made based on the properties of concretes at low cement contents and on experimental and performance data. Because these data are limited, the design procedure is suggested as a preliminary guide. Simplified design charts are presented for conventional highway truck loadings; design data are also given that may be used for aircraft and other loadings.

Organic Optocoupler with Simple Construction as an Effective Linear Current Transceiver.

In this study, it is shown that an efficient organic optocoupler (OPC) can be fabricated using commercially available and solution-processable organic semiconductors. The transmitter is a single-active-layer organic light-emitting diode (OLED) made from a well-known polyparavinylene derivative, Super Yellow. The receiver is an organic light-emitting diode (OLSD) with a single active layer consisting of a mixture of the polymer donor PTB7-Th and the low-molecular-weight acceptor ITIC; the receiver operates without an applied reverse voltage. OLED and OLSD have the same geometry and simple structure without any interlayers: glass/ITO/PEDOT:PSS/(active layer)/Ca/Al; the OPC is formed by OLED and OLSD which adhere tightly to each other. Despite its simple structure, the OPC showed a current transfer ratio of 0.13%, good linearity, and good dynamic performance: a three-decibel cutoff frequency of 170 kHz and response times to a step change in current at the OPC input of 2 μs. Compared to most organic OPC devices with similar performance parameters, where the transmitter and receiver have complex structures with additional interlayers between the active layers and electrodes and the need to apply a reverse voltage to the receiver, the simple design of our OPC reduces the number of fabrication steps and greatly simplifies the device fabrication process.

Robust Finger Vein Presentation Attack Detection Using XceptionNet-based Modified Depthwise Separable Convolutional Neural Network

Finger vein presentation attack detection (FVPAD) biometric systems have seen substantial enhancements through the application of deep learning convolutional neural networks (DCNN). This advancement led to increased complexity, parameters and resource requirements. To address these challenges, a novel modification to the first entry flow of the XceptionNet architecture based on customized depthwise separable convolution (DSC) CNN-based for extracting robust features from FV images to detect spoofing attacks is proposed in this paper. The proposed approach stands out for its simplicity in design, fewer parameters, reduced computational load, minimal resource and equipment needs, and minimum data overflow while maintaining high accuracy in verification and classification tasks. The developed FVPAD system includes FV image data preprocessing and augmentation, a modified XceptionNet architecture based on DSC to deeply extract robust features. Finally, the fully connected (FC) layers exclusively use the SoftMax activation function to normalize, predict and classify output classes. The model was evaluated on cropped FV images from the IDIAP and SCUT-SFVD datasets, achieving high accuracy rates of 100% and 99.499%, respectively. It also has the lowest number of trainable parameters at 131,106 acquired from fifteen convolutional and depth-separable convolution layers.

High-Gain Observer in Fuel Cell and Cascaded DC-DC Boost Converter System

In this study, we propose using a high-gain observer (HGO) in fuel cell systems and the FC-cascade boost converter to achieve precise state estimation and improve control accuracy. The HGO offers significant advantages, including robustness to disturbances, simplicity of design, and reduced dependency on costly sensors, thereby enhancing system performance and reducing operational costs. Our results demonstrate the superior accuracy and reliability of this approach, confirming its potential as a promising solution for fuel cell applications.

The effect of chimney entrance slope and constricted section on the performance of solar chimney power plants: A CFD approach

The depletion of hydrocarbon resources and climate change are major global issues which need to be solved urgently. Sun is a clean, inexhaustible, sustainable energy source which has the capacity to meet the future energy demands. Solar chimney power plants (SCPPs) with a simple design are competent to generate large-scale electricity. Primary components of SCPP are the chimney, turbine, and collector. In this work, impact of the chimney entrance slope and narrowed section on performance of SCPP is scrutinized. A computational fluid dynamics model (CFD) is constructed based on Manzanares plant with a chimney height (H) of 194.6 m via ANSYS FLUENT. The novel configurations are generated by changing the chimney inlet slope, θ (45°-85°) and radius of the constricted section with a fixed height (H/28). The findings demonstrate that a decrease in the slope with the constricted section improves the velocity, power and turbine pressure drop. The highest velocity of 17.9 m/s is gained for the configuration with θ = 85° compared to that of 14.3 m/s obtained for the base (θ = 45°) at 1000 W/m2. This configuration enhances power output to 60.4 kW with a rise of 31.3% in comparison to the base case at 1000 W/m2.

Freeze-Casting Mold-Based Scalable Synthesis of Directional Graphene Aerogels with Long-Range Pore Alignment for Energy Applications.

In various applications, the pore structure of a porous medium must be controlled to facilitate heat and mass transfer, which considerably influence the system performance. Freeze-casting is a versatile technique for creating aligned pores; However, because of the complexity of the associated equipment and the energy inefficiency of liquid-nitrogen-based cooling in a room-temperature environment, limits scalability for industrial applications. This study is aimed at establishing a novel freeze-casting strategy with a simple mold design combining heat-conductive and insulating materials for long-range pore alignment via directional ice growth under deep-freezing conditions, rendering it feasible for large-scale production. Using this technique, axially aligned (Axial-GA) is developed, radially aligned (Radial-GA), and randomly distributed (Random-GA) pore structures within NaBr-impregnated graphene aerogel (GA-NaBr) configurations, demonstrating enhanced ammonia adsorption for thermal energy management. The pore structure exerted notable effects on the ammonia adsorption behavior, with Radial-GA exhibiting a higher adsorption rate due to reduced ammonia transit distance. The Radial-GA-NaBr structure demonstrated unique adsorption characteristics, retaining ≈85% of the adsorption capacity and achieving a ≈270% adsorption rate gain compared with pure NaBr powder. Overall, this research demonstrates the fabrication of aerogels with various configurations and orientations using facile and scalable methods, thereby expanding their industrial applications.

A simple and versatile photothermal dual-curing system design based on phytophenol derivatives and thiol chemistry for potential electronic encapsulant application

Given the diversity of thiol chemistry, researchers are actively exploring its potential as a versatile compound. This paper presents the synthesis of three bio-based multifunctional monomers (EPMG, EPBEG, EPBEF) containing allyl and epoxy groups using phytophenols (magnolol and eugenol) as raw materials. Photothermal dual curing was performed using pentaerythritol tetrakis(3-mercaptopropionate) (PETMP). Comprehensive studies and comparisons of the cured systems were conducted, including curing kinetics, mechanical properties, dielectric properties, and transmittance. The effect of the curing sequence was systematically investigated. The results demonstrate that as the curing proceeds, the mechanical properties and glass transition temperature (Tg) of the material improve significantly, and the dual curing process exhibits excellent bonding, dielectric, and ultraviolet (UV) shielding performance. Moreover, the differences in monomer structure (methoxy, benzene ring connection) also impact the properties of the monomers and the performance of the material. This work provides a novel approach to designing epoxy monomer structures and developing bio-based single-component dual-curing systems. This thiol-mediated dual-curing system has potential applications in electronic materials and personal protective equipment can contribute to achieving miniaturization, precision, and integration in various applications.

Simplified design of power transmission tower: Strategic variable analysis study

Simplified design of power transmission tower: Strategic variable analysis study

Activating discharge and inhibiting self-corrosion by adding indium to the anode of Mg-air battery.

Self-corrosion and low practical voltage of anodes severely limit the usage of Mg-air batteries. Although many elements, including indium (In), have been used to enhance the discharge characteristics of Mg anodes, unclear mechanism of the action of a single element and lack of research on binary alloys as anodes have restricted the development of Mg-air batteries. Herein, Mg-xIn (x = 0.5, 1, 2, 4) alloys were melted as anode materials for Mg-air batteries. The In element in the Mg-In binary alloy activated the discharge process of the anode and inhibited self-corrosion and chunk effect, thereby greatly improving the voltage and anodic efficiency of the batteries. Mg-air batteries assembled from Mg-1In anode reached voltages exceeding 1.5 V at low current density and over 1.1 V even at 40.0 mA cm-2. The Mg-1In anode exhibited a discharge efficiency greater than 63.2% at all current densities and demonstrated a peak specific energy of 2100.2 mW h g-1. Furthermore, the Mg-1In anode performed well in long-term, intermittent, and constant-power discharges. The simple design of binary alloy and the activation and inhibition mechanisms of the In element provide a new avenue for Mg anode development.

Emerging Passive Cooling Technologies and Their Multidisciplinary Applications: An Integrative Review

The persistent rise in temperature driven by the emission of greenhouse gases presents a pressing contemporary challenge, fostering innovative cooling techniques. Currently, passive cooling technologies have gained attention in various research fields for their effectiveness in combating heat accumulation. Compared to traditional active cooling methods, which rely on electricity or other energy sources, passive cooling significantly reduces energy consumption and electricity demand. These technologies have demonstrated the potential for temperature reductions of ~1°C–24°C, translating to substantial electricity savings of about 2–300 kWh/year. This paper uses an integrative review approach to highlight the fundamental principles and design strategies underlying passive cooling technologies, such as phase change materials, radiative cooling, and evaporative cooling. Special emphasis is placed on their potential implementation, from preserving biological materials to cooling buildings, electronics, and personal clothing. Passive cooling methods offer cost savings over time due to lower maintenance and operational costs and potentially simpler designs.

Numerical investigation and fabrication of L-turns spiral micromixers for enhanced mixing performance

In this paper, we simulated and fabricated an L-turn spiral passive micromixer design and compared it with a simple spiral design, both of which are particularly effective for improving mixing efficiency in bio-applications. Centrifugal force and secondary flow can be strengthened by the recommended spiral design. Furthermore, the L-turns improved the displacement of the velocity profile across the channel width leading to enhanced mixing efficiency. The micromixer performance was evaluated through a series of simulations and the effects of different parameters such as channel dimensions, inter-channel gaps, and flow rate were assessed. The contact area between the fluids is affected by the mentioned features, resulting in improved mixing efficiency. A mixing quality of over 90% is achieved after 26 mm (approximately one-third of the total channel length) at a flow rate of 25 μl/min, with a molecular diffusion coefficient of 1 × 10−10 m2/s. At last, the proposed fabrication process was presented to show the feasibility of the design.