Detailed Design Research Articles

Design, Development and Application of a Modular Electromagnetic Induction (EMI) Sensor for Near-Surface Geophysical Surveys.

Low-frequency electromagnetic induction (EMI) is a non-invasive geophysical method that is based on the induction of electromagnetic (EM) waves into the subsurface to quantify changes in electrical conductivity. In this study, we present an open (design details and software are accessible) and modular system for the collection of EMI data. The instrument proposed allows for the separations between the transmitter to be adjusted and up to four receiving antennas as well as the acquisition frequency (in the range between 3 and 50 kHz) to permit measurements with variable depth of investigation. The sensor provides access to raw data and the software described in this study allows control of the signal processing chain. The design specifications permit apparent conductivity measurements in the range of between 1 mS/m and 1000 mS/m, with a resolution of 1.0 mS/m and with a sampling rate of up to 10 samples per second. The sensor allows for a synchronous acquisition of a time stamp and a location stamp for each data sample. The sensor has a mass of less than 5 kg, is portable and suitable for one-person operation, provides 4 h of operation time on one battery charge, and provides sufficient rigidity for practical field operations.

Design and Modeling of a DC-Link Capacitor Droop Controller for a PV System: A Comprehensive Review

This paper presents an in-depth review of the design and modeling of a DC-link capacitor droop controller for photovoltaic (PV) systems. The DC-link capacitor droop controller plays a crucial role in stabilising the DC-link voltage, managing power fluctuations, and ensuring reliable operation of grid-connected PV systems. This review covers the fundamental principles of droop control, the architecture of PV systems, the role of DC-link capacitors, and the detailed design process of the droop controller. Additionally, we explore various control strategies, simulation methods, practical implementations, and future research directions in this field. Keywords: DC-Link Capacitor, Droop Control, PV System, Grid-Connected, Stability, Power Quality, Renewable Energy

Shared EV charging stations for the Austin area: opportunities for public-private partnerships

ABSTRACT Many nations are hoping to shift to less unsustainable transport systems via adoption of electric vehicles (EVs). Developing sufficient EV charging stations (EVCS) is central to widespread adoption and use. Co-locating private and public EVCS cords is a promising way to lower costs, increase access, and facilitate EVCS developments. This study explores potential sites for and estimates actual costs of co-locating public-private (PP) charging hubs across the City of Austin, reflecting demand and supply features. Existing EVCS sites, sizes, and charging speeds are used inside the agent-based POLARIS model for microsimulation of travel choices and EV use. Site design details are also provided.

Design and control of a side dense transplanting machine for sweet potato seedlings on mulch film

At present, China is the leading country in sweet potato cultivation worldwide. However, there are still several problems such as high labor intensity, low efficiency of manual transplanting, and lack of machinery for side transplanting for sweet potato seedlings on mulch film. Therefore, a side dense transplanting machine for sweet potato seedlings on mulch film is designed, using a multi-row side transplanting method. It is mainly composed of a transplanting device, a seedling conveying device, a traveling device, and a control system. Based on the agronomic requirements for sweet potato transplanting, the study focuses on the structure and working principle of the complete machine. It involves the detailed structural design and motion analysis of the crank-rocker and cam of the transplanting device. Based on the sweet potato seedlings transportation plan, parameters such as the vertical height of the seedling conveying device, the size of the support frame, and the relative relationship between position of the transplanting device are determined. To ensure the smooth transplantation of sweet potato seedlings, the motor parameters required for each device are calculated and determined. An Arduino control system is developed to manage the coordinated movement of each device. Positioning components are integrated to ensure accurate coordination between the transplanting device and the seedling conveying device. This setup enables the seedling claws to pick sweet potato seedlings and perform the side transplanting on the mulch film. Field test results show the missed rate of seedlings, the qualified rate of transplanting and the qualified rate of transplanting depth are 4.13 %, 91.62 % and 93.86 % respectively. The transplant spacing coefficient of variation and the average spacing between seedlings are 1.90 and 177.06 mm respectively. All indicators of the transplanting machine meet the agronomic requirements for side dense transplanting for sweet potato seedlings on mulch film. The transplanting machine is integrated with sweet potato seedling transplanting agronomy, achieving mechanized transplanting of sweet potato seedlings, reducing labor intensity, and promoting the quality and efficiency of sweet potato production. This research provides a reference for the development of sweet potato seedlings transplanting equipment.

Optimizing MEP design in early AEC projects through generative design

The digital transformation of the AEC industry through BIM has improved productivity during detailed design and construction planning phases. Early design choices influence a project's success but have yet to benefit from BIM-based approaches. This paper investigates the feasibility and acceptance of employing Generative Design (GD) to optimize early Mechanical, Electrical, and Plumbing (MEP) designs in residential real estate for space efficiency. Interviews indicate the main issue is acceptance due to the belief that a GD approach needs to be more robust. BIM is integrated with GD, utilizing the architectural layout (IFC) as input to generate design variants tailored to minimize technical space while ensuring installation feasibility. Robustness is assessed via Monte Carlo Simulation, revealing an estimated success rate of 99% (81% with 95% confidence). These results quantify the robustness of the approach, paving the way to broader acceptance of GD in the early phases of AEC projects.

Enhancing Energy Supply Reliability for University Lecture Halls Using Photovoltaic-Battery Microgrids: A South African Case Study

Institutions of higher learning in South Africa are grappling with occasional power outages in lecture halls, leading to disruptions in academic activities and occasional loss of lecture hours. Therefore, this study presents a comprehensive evaluation of a grid-connected solar PV/Li-ion battery microgrid (μG) system aimed at maintaining a constant power supply to selected lecture halls at a university in the Western Cape, South Africa. The microgrid design, modelling, and simulations, conducted in the MATLAB/Simulink environment, include the solar PV, Li-ion battery, energy consumption of the lecture halls (load profile), boost converter, bidirectional converter, and grid. Using the detailed design, modelling, and simulation, the study evaluates the economic and environmental impacts of integrating μGs, focusing on enhancing energy reliability, reducing operational costs, and mitigating CO2 emissions. The results indicate that integrating the microgrid resulted in a significant 51% reduction in energy cost and a decrease in greenhouse gas emissions by 530 kgCO2e per hour. In Cases 2 and 4, where the battery supplied power, the annual battery degradation costs are 6.08% and 14.9% of the initial cost, respectively. The μG ensures an uninterrupted power supply and improves the overall reliability of the university’s energy infrastructure. It promotes environmental sustainability goals of zero emissions and maintains continuous academic activities during grid outages. Furthermore, it fosters a conducive learning environment, supports innovation and creativity in sustainable energy technologies, and sets a standard for other higher education institutions to integrate renewable energy-powered μGs.

Design and experimental evaluation of a novel flow-mode magnetorheological damper without accumulator

Researchers in the field of vibration control have shown increasing interest in magneto-rheological dampers (MRDs) in recent years. Conventional flow-mode MRDs typically employ a gas chamber as an accumulator to accommodate volume changes and promote fluid communication. However, this approach introduces manufacturing complexities and raises production costs. To overcome these challenges, we propose a novel configuration for flow-mode MRDs that replaces the accumulator with a structural constraint. This modification leads to a more compact and cost-effective MRD solution suitable for engineering applications. This paper presents an introduction, followed by the configuration and design of the novel MRD for a case study involving a vehicle suspension system. To enhance output performance, we optimize the significant geometry of the damper using the finite element method (FEM), taking into account the damping force, off-state force, and inductive time constant of the damper. Based on the optimal simulation results, we provide a detailed design of the optimized flow-mode MRD without an accumulator for prototype fabrication. To assess the practical performance of the proposed MRD prototype, we conducted experiments on a test rig and engaged in comprehensive discussions based on the obtained results.

Desain Instruksional Pembelajaran Matematika Pada Materi Bangun Ruang Untuk Siswa Kelas VII SMP

In the world of education, instructional design development is important to do in order to create improvements in the teaching and learning process. The purpose of this study is to provide an overview of instructional design design in learning mathematics in class VII junior high school building materials. The research method used is Systematic Literature Review using several article reviews indexed by Sinta and Scopus. The search for article reviews was carried out on several platforms including google scholar and eric. The results showed that the learning design used the Problem-based Learning model with the Teaching at the Right Level approach with the help of technology and several assessment instruments. Further details of the learning design are explained in detail in the results and discussion section of this article.

Harnessing spin effects for heterogeneous single-atom spin catalysis.

This perspective explores detailed structural design and strategies for spin regulation in single-atom spin catalysis, enabling unparalleled efficiency in chemical transformations through the harnessing of spin effects combined with atomic precision of active sites.

A reconfigurable wireless power transfer system with constant exciting current for charging multiple batteries

At present, wireless power transfer (WPT) systems with constant current (CC) or constant voltage (CV) characteristics are typically achieved using a single transmitter and single pickup (STSP) configuration, which cannot transfer power to multiple battery loads simultaneously. In this paper, the LCC-LCC/S reconfigurable topology is proposed to realize the CC-to-CV transition for multiple battery loads. An LCC topology is designed on the primary side to achieve a constant current (0.362A) flowing through the transmitting coil to enable independent operation of power pickups. A reconfigurable LCC/S topology is designed on the secondary side to achieve the CC-to-CV transition of the battery loads. The received power from the pickups remains unaffected when pickups are moved in or out or are in different operating modes (CC or CV). The circuit can maintain zero phase angle (ZPA) operation, which greatly enhances the overall power density of the system. Additionally, detailed design process for the compensation parameters on both the primary and secondary sides are provided. Theoretical analysis proves that good system stability and robustness can be obtained in the case of variable quantity of pickups and quality factors of coils. The experimental prototype was built, with the CC value for the battery load designed at 0.7A and the CV value designed at 8 V. Experimental results demonstrate the smooth CC-to-CV transition of the proposed WPT system (with 3 pickups) at a power output of 15.4 W, and the system’s maximum efficiency can reach 75.5 %.

Novel side-reactor dividing wall column and reactive distillation process for enhanced electronic-grade propylene glycol monomethyl ether acetate production

The semiconductor industry is experiencing rapid growth and has become one of the largest sectors in the world. Propylene glycol monomethyl ether acetate (PGMEA) is prized for its exceptional properties and its ability to meet the stringent requirements as a solvent for electronic processing. This work aims to enhance the production of electronic-grade PGMEA through a practical and advanced intensified configuration. First, the kinetic reactor for propylene glycol monomethyl ether (PGME) synthesis has been modeled and pinpointed optimal operating conditions through sensitivity analysis. Subsequently, several process alternatives incorporating intensified techniques, such as the dividing wall column (DWC), pressure swing distillation (PSD), reactive DWC (RDWC), and side-reactor DWC (SR-DWC), have been investigated. These processes have been systematically designed and optimized through a sequential design procedure. Response surface methodology, a practical optimization method, has been employed to optimize the complex column's structure with the help of Aspen Plus and Minitab. Energy requirements and costs of all process alternatives were evaluated for a fair comparison. The SR-DWC-RD process has emerged as the most promising option, as it can save up to 11.5 % in energy requirements and 19.9 % in total annual costs. This practical design, complete with detailed optimal design parameters, presents significant opportunities for improving industrial PGMEA production.

Engineering of a CMC aeronautical muffler

This work explores the feasibility of adopting an LSI produced C/SiC composite to build an aeronautical Auxiliary Power Unit system muffler. The study first covers the experimental material characterization through tensile and compressive tests. The material properties are characterized also after exposing the samples to an oxidizing atmosphere, that is typical for the proposed application. The material response is characterized by significant non-linearities and a pseudo plastic response, which were numerically modeled using a Drucker-Prager model. The detailed design of the muffler is described and verified, for different loading conditions, using a Finite Element model. Finally, a full-scale prototype is produced and assembled, thus proving the technological feasibility of the design. The manufacturing phase required to study and understand the phenomena that were leading to defects in the proposed closed axial symmetric shape, and to implement suitable technological solutions in order to get an acceptable prototype.

The study of the stress state of the aft wing of the hydrofoil vessel for 120 passengers

The article presents a comparison of the results of stress state calculation of the aft wing of hydrofoil vessel 03830 designed by “SeaTech”. The aft wing in this project takes 70% of the hull weight of the vessel, so it is the most loaded. In contrast to the majority of the river hydrofoil projects, the aft wing construction is not solid, but a set, so the use of the rod design scheme for its calculation, stipulated by the Rules of the Russian Classification Society (RCS), is questionable. The aft wing operates in the fluid flow behind the bow wing, so also questionable is the recommendation of the RCS on the uniform distribution of the load along the length and chord of the wing. In this regard, two structural schemes of the wing are considered: rod and volumetric. The calculations of these schemes are performed by the finite element method, using the ANSYS Mechanical program package. The loading of the rod scheme was performed using the RCS recommendations, and the volumetric scheme was calculated for two types of loading: by RCS and by the results of the calculation performed in the AUTOWING software package based on the discrete vortex theory. The performed calculations showed that the stresses in the wing calculated on the basis of the RCS recommendations are significantly lower compared to a more detailed design scheme that takes into account the peculiarities of the wing structure and its loading.

Numerical investigation of different building configurations for improving outdoor spatial ventilation conditions in strip-type residential neighbourhoods

Understanding the influence of building configurations on spatial wind flows is essential for architects to optimize urban ventilation in the design process. However, the design changes in urban form are abundant and many detailed design variations were not examined. This study aims to explore the potential of spatial forms to improve wind conditions in strip-type residential neighbourhoods. Several specific building design variations were investigated using computational fluid dynamic (CFD) simulations. The ventilation performance indicators including spatial averaged wind velocity (<V>), purging flow rate (PFR), and net escape velocity (NEV) were adopted to quantify the effects of design changes on spatial ventilation efficiency of overall and local residential spaces. The results show that the buildings with staggers of residential units could have a noticeable impact on the overall residential space, especially when the wind direction is inclined or parallel to the corridor space between the strip buildings. The PFR and < V > values of the residential space can be reduced by 19% and 18%. Building length variation and square setting can be beneficial to the ventilation conditions of the local residential spaces.

Development of a Flipped Learning Instructional Design Model for Clinical Reasoning Development in Preclinical Students Based on Illness Scripts

Objectives Recent educational demands have arisen in medical schools to systematically and directly teach clinical reasoning skills to preclinical medical students. This has highlighted the need for instructional design models to guide clinical professors in designing such educational programs. Instructional design models can reduce the challenges faced by clinical professors during course design by providing comprehensive guidance on the process. However, despite this practical necessity, research in this area is lacking. Thus, this study aimed to develop and validate an instructional design model and accompanying detailed design guidelines for developing a flipped learning course aimed at enhancing clinical reasoning skills in preclinical medical students based on illness scripts. The purposes of this study were to specify variables related to convergence competency, and to analyze the structural relationships among them. Methods To achieve this goal, developmental research, including model development and validation, was employed. The instructional design model and detailed design guidelines were developed based on literature reviews and a case study, and model validation was conducted through two rounds of expert validation and a usability test. Results The developed instructional design model was structured as a procedural model explaining the steps of instructional design, and designed at two levels (course and individual class). Furthermore, the model comprises six stages and 22 major design activities, while the detailed design guidelines include comprehensive explanations of design activities carried out in each stage of instructional design. Conclusions The developed instructional design model and detailed design guidelines can provide clinical professors with practical assistance in systematically designing flipped learning to enhance clinical reasoning skills in preclinical medical students based on illness scripts.

Prefabricated bolted PEC beam-to-CFST column joints: Development and its seismic behavior

This paper developed a novel bolted connection of prefabricated partially encased composite (PEC) beam to concrete-filled steel tubular (CFST) column by end-plates or π-connectors, and two joints with varying design details were tested subjected to cyclic loading. The seismic performance of the developed connections was investigated by experimental and finite element (FE) analysis. It was observed that both the two type connections exhibited concrete crushing within the PEC beam, accompanied by localized buckling and eventual fracture of the flanges in the main steel component of the beam. At the same time, other components were essentially in the elastic phase, such as end-plates, π-connectors, high-strength bolts, and column steel tubes. The bolted end-plate connections demonstrated excellent hysteretic performance, exhibiting high ductility factors. The stiffness, ductility, and energy dissipation capacity of the bolted π-connector connections were significantly diminished due to the influence of relative slippage between the π-connectors and the beams, in stark contrast to the bolted end-plate connection. According to Eurocode 3, the suggested connection configurations exhibited semi-rigid behavior and full-strength characteristics for non-sway frames.

Performance of different microfluidic devices in continuous liquid-liquid separation

Droplet-based microfluidics exhibit numerous benefits leading to relevant innovations and many applications in various fields. The precise handling of droplets in capillaries, including droplet formation, manipulation, and separation, is essential for successful operation. Only a few reports are known concerning the separation of segmented flows, particularly the continuous separation of droplets, which is of high interest regarding the control of biochemical and chemical reactions or other applications where the contact time of the involved phases is crucial. Here, the separation must be flexible and adjusted to different flow parameters, such as the surface tension, the volumetric flow rates, and their ratios. This contribution presents two novel open-source approaches based on additive manufacturing and mechanical deforming for continuous liquid–liquid separation under various flow conditions. The Laplace pressure is the driving force for the separation, which is adjusted to the flow conditions by adapting the distance of pinning points provided by the design of the devices. Details of the device design and experimental setup are shown along with limitations to promote further development and to increase availability for researchers. With the right parameters, sophisticated separations can be realized by inexpensive laboratory equipment and simple control of them. It was found that the distance between the pinning points needs to enlarged for increasing volumetric flow rates and reduced for higher viscosities of the continuous phase respectively higher amounts of the dispersed phase. The open source approach of this article expands the exploration space in addition to commercially available phase separators only available to a selected group of people.Graphical

Database of tall pre-Northridge steel moment frames for earthquake performance evaluations

This article describes a detailed database of tall steel moment frame buildings that are representative of the construction practices in San Francisco prior to the 1994 Northridge earthquake. The database contains design details that affect the structural performance of steel moment frames, including frame geometry, member cross-section sizes, and gravity system characteristics. This database also captures irregularities that might impact seismic response, such as podiums, setbacks, mass concentrations (mechanical, electrical, and plumbing (MEP) floors), interrupted column lines, and atriums. The database includes information on 89 moment frame buildings, 14 of which were built before 1960 and are constructed with riveted connections, while the remaining 75 have welded flange connections like those that suffered brittle fracture during the 1994 Northridge earthquake. The buildings are further distinguished between space frame, perimeter frame, and partial space frame systems. For about half (41/89) of the buildings in the database, section sizes of representative structural members were collected, which enabled the evaluation of the seismic design, elastic, and inelastic response using computational workflows. The design diagnostics indicate that most of the buildings meet the minimum seismic strength and strong-column weak-beam requirements of modern building codes, even though they were not necessarily designed with this intent. On the contrary, about one-third of the buildings do not meet the seismic design drift limit of current codes, and about half of them have weak beam-column panel zones. This database, associated structural analysis models, and processing scripts are published at DesignSafe https://doi.org/10.17603/ds2-wjad-r340 to facilitate collaboration and continued development of open-source data for high-resolution simulations to inform risk mitigation strategies on a regional scale.

Reduced Kinematic Error for Position Accuracy in a High-Torque, Lightweight Actuator

In this paper, we propose the design, development, and testing of high-torque and lightweight actuators suitable for lightweight robotic applications. The detailed design of the actuator module is described, and its performance evaluation is also presented. Further, the mathematical modelling of the actuator is discussed. Various performance analysis tests were carried out for the elucidation of the designed actuator, which included primarily position, velocity, and torque analyses. The position accuracy analysis included position repeatability at the maximum payload for calculating the acceptable tolerance. The velocity elucidation included a velocity test for the variable load. The torque analysis of the actuator was completed at different supply currents. These tests and the results indicate that the proposed actuator has high precision in reaching the desired position and provides a stabilized performance with variable loads up to the limit for which it was designed. Based on the torque output and the weight, the proposed actuator could be a good fit for lightweight robotic applications.

Application of bi-directional evolutionary structural optimization to the design of an innovative pedestrian bridge

With rapid advances in design methods and structural analysis techniques, computational generative design strategies have been adopted more widely in the field of architecture and engineering. As a performance-based design technique to find out the most efficient structural form, topology optimization provides a powerful tool for designers to explore lightweight and elegant structures. Building on this background, this study proposes an innovative pedestrian bridge design, which covers the process from conceptualization to detailed design implementation. This pedestrian bridge, with a main span of 152 m, needs to meet some unique architectural requirements, while addressing multiple engineering challenges. Aiming to reduce the depth of the girder but still meeting the load-carrying capacity requirements, the superstructure of this bridge adopts a variable-depth spinal-shaped girder in the center of its deck, thus forming an elegant curving facade, from which one pathway cantilevers on either side. At one end of the bridge, given considerable elevation difference between the bridge deck and the ground, a two-level Fibonacci-type spiral-shaped bicycle ramp is provided. The superstructure is supported by a series of organic tree-shaped branching piers resulting from the topology optimization. The ingenious design for the elegant profile of the bicycle ramp generates an enjoyable and dynamic crossing experience, with scenic views in all directions. By virtue of technological innovation, the pedestrian bridge is expected to create an iconic, cost-effective, and low-maintenance solution. A brief overview of the theoretical background of the bi-directional evolutionary structure optimization (BESO) and the multi-material BESO approach is also offered in this paper, while the construction requirements and challenges, conceptual development process, form-finding strategy, detailed design, and construction method of the bridge are presented.