Designs, Volume 8, Issue 1 (February 2024) – 18 articles

The road transport system is expanding considerably in developing countries. Villages are connecting to major cities for business, education, health, and many other reasons because of road development and smooth transportation. There has been a rise in the number of road accidents observed, caused by abruptly appearing dividers on roads and a lack of required signage systems. This paper discusses scenarios of accidents due to such abruptly appearing dividers and offers a strategy to design appropriate signage to avoid road accidents in the future. It has been observed that permanent or movable arbitrary fixtures, such as a barricade or a small partition block wall, are installed to separate lanes, in addition to white-colored stripes that are typically employed for lane separation on roads. These fixtures, although they are intended as lane-dividing solutions on roads, cause serious, and at times, fatal accidents, due their sudden, uninitiated appearance on the road. To address this problem, alternative signage designs were designed and tested on Indian roads, based on human cognitive responses and visual attention analysis on signage using an eye-tracking method. In addition, the semantic quality and legibility of alternate signage designs were evaluated using a questionnaire to judge their overall efficacy. Hence, the best signage design solution is proposed for implementation near or before occurrences of road dividers to avoid accidents. Full article

Although solar photovoltaic (PV) system costs have declined, capital cost remains a barrier to widespread adoption. Do-it-yourself (DIY) system designs can significantly reduce labor costs, but if they are not attached to a building structure, they require ground penetrating footings. This is not technically and economically feasible at all sites. To overcome these challenges, this study details systems designed to (1) eliminate drilling holes and pouring concrete, (2) propose solutions for both fixed and variable tilt systems, (3) remain cost effective, and (4) allow for modifications to best fit the user’s needs. The ballast-supported foundations are analyzed for eight systems by proposing two separate ballast designs: one for a single line of post systems, and one for a double line of post systems, both built on a 4-kW basis. The results of the analysis found that both designs are slightly more expensive than typical in-ground concrete systems by 25% (assuming rocks are purchased at a landscaping company), but the overall DIY system’s costs remain economically advantageous. Sensitivity analyses are conducted to show how modifications to the dimensions influence the weight of the system and thus change the economic value of the design, so users can trade dimensional freedom for cost savings, and vice versa. Overall, all wood-based PV racking system designs provide users with cost-effective and easy DIY alternatives to conventional metal racking, and the novel ballast systems presented provide more versatility for PV systems installations. Full article

Commercially available cochlear implants are designed to aid profoundly deaf people in understanding speech and environmental sounds. A typical cochlear implant uses a bank of bandpass filters to decompose an audio signal into a set of dynamic signals. These filters’ critical center frequencies $f_0$ imitate the human cochlea’s vibration patterns caused by audio signals. Gammatone filters (GTFs), with two unique characteristics: (a) an appropriate “pseudo resonant” frequency transfer function, mimicking the human cochlea, and (b) realizing efficient hardware implementation, could demonstrate them as unique candidates for cochlear implant design. Although GTFs have recently attracted considerable attention from researchers, a comprehensive exposition of GTFs is still absent in the literature. This paper starts by enumerating the impulse response of GTFs. Then, the magnitude spectrum, $\left|H\right(f\left)\right|$, and bandwidth, more specifically, the equivalent rectangular bandwidth (ERB) of GTFs, are derived. The simulation results suggested that optimally chosen filter parameters, e.g., critical center frequencies,$f_0$; temporal decay parameter, $b$; and order of the filter, $n$, can minimize the interference of the filter bank frequencies and very likely model the filter bandwidth (ERB), independent of $\frac{f_0}{b}$. Finally, these optimized filters are applied to delineate a filter bank for a cochlear implant design based on the Clarion processor model. Full article

In this research, a numerical approach is created to assess the effective parameters of power transformer thermal management and, as a result, improve their cooling systems. This study analyzes the radiator’s thermal performance across several arrangements and optimizes the dimensions and configurations for varied cooling loads from a techno-economic perspective. The optimization criteria were the radiator’s height (L), fin spacing (D), and number of fins (N). Due to the great complexity of the generated models, the coupled thermo-hydraulic numerical simulations were carried out on a computer cluster. An in-house radiator test facility was constructed for the experiments in order to verify the numerical model. The simulation findings accord well with the empirically obtained values. A total of 76 radiator sets were investigated. Following that, the generated findings were used to perform an optimization analysis. Finally, the response surface method was used to establish an ideal radiator layout for the specified cooling capacity at the lowest possible cost. These findings reveal that the best cooling performance is obtained when the spacing between the fins is 50 mm. Cooling capacity per unit cost rises as radiator size decreases. The cost factor and geometric details were shown to have strong connections. Full article

The characterization of small-size engines requires dedicated rigs that are usually used for loading the power unit. Adding the possibility of motoring the engine is an important advantage that allows more detailed information on operating characteristics. It can be used for obtaining precious data that contribute to the development of more accurate numerical models and subsequent validation. Cost competitiveness is another essential aspect of small-size engines, given that development efforts need to be contained as much as possible. Within this context, the present work developed and tested a setup capable of cranking and motoring a small-size 50 cc spark ignition engine. Two configurations were considered for coupling an electric motor to the power unit: the first through a pulley-belt transmission and the second via a plastic clutch assembly. The main idea was to ensure the capability of motoring the engine up to a rotational velocity of 6000 rpm. Engine load was applied through a 1 kW electric generator connected directly to the crankshaft. The overall setup was designed in the two configurations and a stress–strain analysis was performed. The belt-driven option was found to be more favorable in terms of mechanical component requirements, showing a safety factor of around 4.0, while the plastic clutch assembly involved a more complex design phase and turned out to be more demanding, with a safety factor of around 2.9. Full article

Development challenges in the domain of superconducting magnets are concentrated on technical problems in the current literature. Organizational, domain-specific challenges are often seen as secondary but must be considered with new holistic development approaches like Model-Based Systems Engineering (MBSE) becoming more popular. This work quantifies the domain challenges and gives the foundation to derive success criteria for design support in the future. A systematic literature review has been conducted to identify the overall domain challenges, and extensive interviews in the CERN technology department have been carried out to identify the development challenges on a practical level. Problems in knowledge management have been identified as a major challenge in the development process and the general literature. The paper concludes by picking up the most important challenges from the interviews and literature and puts them into the context of the authors’ knowledge of electrical magnet design. Full article

Flexible Manufacturing Systems (FMSs) provide a competitive edge in the ever-evolving manufacturing landscape, offering the agility to swiftly adapt to changing customer demands and product lifecycles. Nevertheless, the complex and interconnected nature of FMSs presents a distinct challenge: the evaluation and prioritization of performance variables. This study clarifies a conspicuous research gap by introducing a pioneering approach to evaluating and ranking FMS performance variables. The Best-Worst Method (BWM), a multicriteria decision-making (MCDM) approach, is employed to tackle this challenge. Notably, the BWM excels at resolving intricate issues with limited pairwise comparisons, making it an innovative tool in this context. To implement the BWM, a comprehensive survey of FMS experts from the German manufacturing industry was conducted. The survey, which contained 34 key performance variables identified through an exhaustive literature review and bibliometric analysis, invited experts to assess the variables by comparing the best and worst in terms of their significance to overall FMS performance. The outcomes of the BWM analysis not only offer insights into the factors affecting FMS performance but, more importantly, convey a nuanced ranking of these factors. The findings reveal a distinct hierarchy: the “Quality (Q)” factor emerges as the most critical, followed by “Productivity (P)” and “Flexibility (F)”. In terms of contributions, this study pioneers a novel and comprehensive approach to evaluating and ranking FMS performance variables. It bridges an evident research gap and contributes to the existing literature by offering practical insights that can guide manufacturing companies in identifying and prioritizing the most crucial performance variables for enhancing their FMS competitiveness. Our research acknowledges the potential introduction of biases through expert opinion, delineating the need for further exploration and comparative analyses in diverse industrial contexts. The outcomes of this study bear the potential for cross-industry applicability, laying the groundwork for future investigations in the domain of performance evaluation in manufacturing systems. Full article

In today’s power system landscape, renewable energy (RE) resources play a pivotal role, particularly within the residential sector. Despite the significance of these resources, the intermittent nature of RE resources, influenced by variable weather conditions, poses challenges to their reliability as energy resources. Addressing this challenge, the integration of an energy storage system (ESS) emerges as a viable solution, enabling the storage of surplus energy during peak-generation periods and subsequent release during shortages. One of the great challenges of ESSs is how to design ESSs efficiently. This paper focuses on a distributed power-flow system within a smart home environment, comprising uncontrollable power generators, uncontrollable loads, and multiple energy storage units. To address the challenge of minimizing energy loss in ESSs, this paper proposes a novel approach, called energy-efficient storage capacity with loss reduction (SCALE) scheme, that combines multiple-load power-flow assignment with a load-shifting algorithm to minimize energy loss and determine the optimal energy storage capacity. The optimization problem for optimal energy storage capacity is formalized using linear programming techniques. To validate the proposed scheme, real experimental data from a smart home environment during winter and summer seasons are employed. The results demonstrate the efficacy of the proposed algorithm in significantly reducing energy loss, particularly under winter conditions, and determining optimal energy storage capacity, with reductions of up to 11.4% in energy loss and up to 62.1% in optimal energy storage capacity. Full article

A comprehensive review of uncertainties in power systems, covering modeling, impact, and mitigation, is essential to understand and manage the challenges faced by the electric grid. Uncertainties in power systems can arise from various sources and can have significant implications for grid reliability, stability, and economic efficiency. Australia, susceptible to extreme weather such as wildfires and heavy rainfall, faces vulnerabilities in its power network assets. The decentralized distribution of population centers poses economic challenges in supplying power to remote areas, which is a crucial consideration for the emerging technologies emphasized in this paper. In addition, the evolution of modern power grids, facilitated by deploying the advanced metering infrastructure (AMI), has also brought new challenges to the system due to the risk of cyber-attacks via communication links. However, the existing literature lacks a comprehensive review and analysis of uncertainties in modern power systems, encompassing uncertainties related to weather events, cyber-attacks, and asset management, as well as the advantages and limitations of various mitigation approaches. To fill this void, this review covers a broad spectrum of uncertainties considering their impacts on the power system and explores conventional robust control as well as modern probabilistic and data-driven approaches for modeling and correlating the uncertainty events to the state of the grid for optimal decision making. This article also investigates the development of robust and scenario-based operations, control technologies for microgrids (MGs) and energy storage systems (ESSs), and demand-side frequency control ancillary service (D-FCAS) and reserve provision for frequency regulation to ensure a design of uncertainty-tolerance power system. This review delves into the trade-offs linked with the implementation of mitigation strategies, such as reliability, computational speed, and economic efficiency. It also explores how these strategies may influence the planning and operation of future power grids. Full article

Ensuring an adequate bond between the steel tube and infilled concrete interface plays an essential role in achieving composite action for concrete-filled steel tubular (CFST) columns. Thus, this study proposes a new type of large diameter CFST column where the steel tube is reinforced by shear stoppers. The bearing strength of the infilled concrete is the decisive factor in evaluating the overall working efficiency between infilled concrete and steel tube. In this paper, we use nonlinear finite element analysis (NFEA) to investigate the bearing strength of the infilled concrete concerning the ratio of the steel tube’s diameter to its thickness $(D/t)$, the number of shear stoppers $\left(N\right)$, the height of the shear stopper $\left(h_b\right)$, and the concrete compressive strength (CCS) $\left(f_c^{\prime }\right)$. Our results show that the influencing factors on the bearing strength of the infilled concrete were arranged in descending order as follows: the number of shear stoppers, the height of shear stopper, the CCS, and the $D/t$ ratio. We also analyze and highlight some significant parameters related to the bearing strength of infilled concrete. Full article

The Digital Twin is one of the major technology trends of the last decade. During the course of its rapid expansion into various fields of application, many definitions of the Digital Twin emerged, tailored to its respective applications. Taxonomies can cluster the diversity and define application-specific archetypes. This paper presents a systematic characterization of the Digital Twin in the context of structural mechanics and lightweight design. While the importance of a shared understanding and the development of holistic solutions for implementing Digital Twins in various application areas is widely recognized, a general framework for implementing Digital Twins in structural mechanics has not yet been established. In this paper, we systematically characterize Digital Twins and develop a framework for their application in structural mechanics, enabling the digital design and monitoring of structures for improved performance and maintenance strategies. The key contributions include collecting and clustering design and operational requirements and deriving two central archetypes: structure-designing and structure-monitoring Digital Twins. The primary goal is to reduce the complexity of conceptualizing Digital Twins of structures by providing a preliminary framework and reconsidering the Digital Twins of structures as a holistic system throughout the product life cycle. Overall, in this paper, we take a systematic approach to enhancing the conceptualization and implementation of Digital Twins in structural mechanics. Full article

To reduce the carbon footprint of manufacturing processes, it is necessary to reduce the number of stages in the development process. To this end, integrating additive manufacturing processes with three-dimensional (3D) printing makes it possible to eliminate the need to use tooling for component manufacturing. Furthermore, using 3D printing allows the generation of complex models to optimize different components, reducing the development time and realizing lightweight structures that can be applied in different industries, such as the mobility industry. Printing process parameters have been studied to improve the mechanical properties of printed items. In this regard, although the failure of most structural components occurs under dynamic load, the majority of the evaluations are quasistatic. This work highlights an improvement in fatigue strength under dynamic loads in 3D-printed components through heat treatment. The fatigue resistance was improved regarding the number of cycles and the dispersion of results. This allows 3D-printed polylactic acid components to be structurally used, and increasing their reliability allows their evolution from a prototype to a functional component. Full article

The prohibitive costs of small-scale solar photovoltaic (PV) racks decrease PV adoption velocity. To overcome these costs challenges, an open hardware design method is used to develop two novel variable tilt racking designs. These are the first stilt-mounted racking designs that allow for the manual change of the tilt angle from zero to 90 degrees by varying the length of cables. The racks are designed using the calculated dead, wind, and snow loads for Canada as a conservative design for most of the rest of the world. Structural capacities of the wooden members are then ascertained and the resisting bending moment, shear force, tensile force, and compressive force is calculated for them. A structural and truss analysis is performed to ensure that the racking design withstands the applicable forces. Moreover, the implications of changing the tilt angle on the wooden members/cables used to build the system are also determined. The systems offer significant economic savings ranging from one third to two thirds of the capital expenses of the commercially available alternatives. In addition, the racking designs are easy-to-build and require minimal manufacturing operations, which increases their accessibility. The stilt-mounted designs can be employed for agrivoltaic settings while allowing farm workers shaded, ergonomic access to perform planting, weeding, and harvesting. Full article

Constant pressure variable flow reciprocating axial pumps (CPAP) are used in various applications, where a constant output pressure is maintained when the flow rate changes. When the hydraulic system is at rated pressure or less, the swash plate has maximum tilt, and the pump delivers maximum flow. The swash plate comes into this position thanks to the action of a reactive piston in which there are two springs. However, when the pressure rises above the nominal pressure value, the piston of the hydraulic pressure transducer (HPT) distributes the fluid under pressure to the hydraulic cylinder (HC), which causes a decrease in the tilt angle of the swash plate and a decrease in flow. The CPAP was selected as a component of the hydraulic system of the aircraft for the experimental tests in this paper. The experimental tests covered the structural and working parameters of the pump and analyzed their performance, efficiency and reliability. Experimental tests of structural and operating parameters of the CPAP were carried out in the Laboratory for Hydraulics and Pneumatics “PPT-Namenska” Trstenik on the hydraulic system, which simulated the real conditions prevailing in the hydraulic system of the aircraft. A system was used for data acquisition and recording of pump characteristics, which were obtained during experimental testing. The results of the measurement and testing of the structural parameters of the CPAP are shown in tabular form, and the experimental tests of static characteristics and dynamic behavior are shown diagrammatically. Full article

This paper proposes a robust design-optimization approach for eBike drive units that incorporates the highly variable driver-dependent load collectives and system conditions into a fatigue calculation. In an initial step, the relevant influences and loads on the investigated system are examined and reviewed in relation to the current normative requirements. From a methodical viewpoint, this paper presents a surrogate-based simulation-based approach to assess reliability across the entire geometry according to a probabilistic fatigue calculation. The probabilistic evaluation considers the several measured load collectives of different drivers and driving scenarios to enable a robust and type-oriented bike design. In addition to methods of fatigue calculation, this approach also includes common methods of order reduction and reliability-based design optimization. To avoid additional uncertainties in the calculation, this approach considers a complex critical-plane-based multiaxial-fatigue calculation to correctly evaluate the multiaxial and non-proportional stress state across the whole geometry. A data-based surrogate model that supports the fatigue calculation by predicting the load across the given uncertainties is the key to the efficient assessment of the service life of the eBike. Lastly, the identified uncertainties in the design of eBike drive units are investigated and evaluated by this method. Full article

This study aims to assess the impact of the water ratio and nanoparticle concentration of neat diesel fuel on the performance characteristics of and exhaust gas emissions from diesel engines. The experimental tests were conducted in two stages. In the first stage, the effects of adding water to neat diesel fuel in ratios of 2.5% and 5% on engine performance and emissions characteristics were examined and compared to those of neat diesel at a constant engine speed of 3000 rpm under three different engine loads. A response surface methodology (RSM) based on a central composite design (CCD) was utilized to simulate the design of the experiment. According to the test results, adding water to neat diesel fuel increased the brake-specific fuel consumption and reduced the brake thermal efficiency compared to neat diesel fuel. In the examination of exhaust emissions, hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) in the tested fuel containing 2.5% of water were decreased in comparison to pure diesel fuel by 16.62%, 21.56%, and 60.18%, respectively, on average, through engine loading. In the second stage, due to the trade-off between emissions and performance, the emulsion fuel containing 2.5% of water is chosen as the best emulsion from the previous stage and mixed with aluminum oxide nanoparticles at two dose levels (50 and 100 ppm). With the same engine conditions, the emulsion fuel mixed with 50 ppm of aluminum oxide nanoparticles exhibited the best performance and the lowest emissions compared to the other evaluated fuels. The outcomes of the investigations showed that a low concentration of 50 ppm with a small amount of 11 nm of aluminum oxide nanoparticles combined with a water diesel emulsion is a successful method for improving diesel engine performance while lowering emissions. Additionally, it was found that the mathematical model could accurately predict engine performance parameters and pollution characteristics. Full article

Understanding the phenomena that cause jet oscillations inside funnel-type thin-slab molds is essential for ensuring continuous liquid steel delivery, improving flow pattern control, and increasing plant productivity and the quality of the final product. This research aims to study the effect of the nozzle’s internal design on the fluid dynamics of the nozzle-mold system, focusing on suppressing vorticity generation below the nozzle’s tip. The optimized design of the nozzle forms the basis of the results obtained through numerical simulation. Mathematical modeling involves fundamental equations, the Reynolds Stress Model for turbulence, and the Multiphase Volume of Fluid model. The governing equations are discretized and solved using the implicit iterative-segregated method implemented in FLUENT^®. The main results demonstrate the possibility of controlling jet oscillations even at high casting speeds and deep dives. The proposed modification in the internal geometry of the nozzle is considered capable of modifying the flow pattern inside the mold. The geometric changes correspond with 106% more elongation than the original nozzle; the change is considered 17% of an inverted trapezoidal shape. Furthermore, there was a 2.5 mm increase in the lower part of both ports to compensate for the inverted trapezoidal shape. The newly designed SEN successfully eliminated the issue of jet oscillations inside the mold by effectively preventing the intertwining of the flow. This improvement is a significant upgrade over the original design. At the microscale, a delicate force balance occurs at the tip of the nozzle’s internal bifurcation, which is influenced by fluctuating speeds and ferrostatic pressure. Disrupting this force balance leads to increased oscillations, causing variations in the mass flow rate from one port to another. Consequently, the proposed nozzle optimization design effectively controls microscale fluctuations above this zone in conjunction with changes in flow speed, jet oscillation, and metal–slag interface instability. Full article

Eliminating microbes in low-moisture foods (LMFs) is challenging because this requires the preservation of their raw quality during pasteurization. Vacuum steam pasteurization (VSP) has been shown to be effective in reducing microbes while maintaining food quality. These studies were conducted at a laboratory scale where issues such as steam distribution, penetration, and condensation are not a concern, but in larger samples, these are of primary concern. Hence, this study repurposes a pilot-scale grain moisture conditioner (GMC) into a VSP system with the aim of replicating the lab-scale conditions in larger-scale applications. The modification entailed a series of design alterations, conducting a structural analysis of the conditioning chamber, creating a vacuum environment, ensuring uniform steam distribution, and designing and adding a preheater and a cooling system. Performance tests confirmed that the adapted system replicates the VSP’s lab-scale functionality. The results demonstrated that the VSP system can preheat to beyond 40 °C and achieve an absolute pressure of 11.7 kPa at 85 °C with a 344.7 Pa pressure increase per minute. Furthermore, steam distribution inside the chamber showed no significant variations, and rapid steam evacuation and chamber cooling could be performed simultaneously. The success of these modifications will be used in future experiments. Full article