Design Modifications Research Articles

Numerical investigation of multiple channels module for enhanced water production in membrane distillation

This paper introduces a novel numerical model for investigating the Multiple Channels Direct Contact Membrane Distillation (MCDCMD) process, which features multiple feed and permeate channels separated by membranes. We compare the performance of this new module with that of a conventional module under various operating conditions. The CFD model has been validated against experimental productivity data obtained from the conventional module and also compared with the MCDCMD module. Our findings reveal that the new MCDCMD module significantly improves productivity by 100 % across all tested conditions, as compared to the conventional DCMD laboratory setup. Additionally, employing a feed channel with a thickness of 0.5 mm leads to a 10 % improvement in productivity over the baseline module with a 1 mm thickness, owing to the substantial temperature variance between membrane surfaces. Turbulence intensity further boosts the productivity of pure water, with a 37 % increase observed at a lower velocity of 4.17 cm/s and a 27 % increase at a higher velocity of 68 cm/s. Overall, the proposed MCDCMD module exhibits a remarkable 137 % improvement in productivity relative to the conventional module. Finally, the experiments are performed with the new design of MCDCMD and verified with the CFD model. Our findings suggest that the proposed MCDCMD module could significantly advance the development of an industrial-scale, energy-efficient DCMD process, particularly for producing high-quality water with improved productivity. Future studies may propose various design modifications aimed at achieving an optimized configuration of commercial-scale DCMD technology.

Enhancing geothermal heat pump efficiency with fin creation and microencapsulated PCM: A numerical study

The main cause of global warming is the emission of carbon dioxide from fossil fuels. Several methods to reduce CO2 emissions have been explored to ensure energy conservation. Many researchers have focused on renewable energy sources for this reason. Ground-source heat pumps (GSHPs) have emerged as a popular alternative in various sectors that utilize shallow geothermal energy sources for heating and cooling. This study presents a novel approach to enhancing the efficiency of geothermal heat exchangers, a critical component of GSHPs, through numerical simulation using computational fluid dynamics (CFD) with Ansys Fluent software. The research investigates the impact of adding four models of spiral fins to the exterior body of the heat exchanger: single spiral and double spiral configurations with pitches of 60 mm and 40 mm, respectively. Additionally, the study explores the effect of incorporating microencapsulated phase change materials (PCMs) with volume fractions of 0 %, 10 %, 30 %, and 50 % into the backfill material surrounding the heat exchanger. The results demonstrate that the double spiral fins with a 40 mm pitch significantly enhance thermal efficiency by reducing the output temperature by up to 1 °C compared to the model without fins. Furthermore, the addition of 50 % microencapsulated PCM by volume to the backfill material can further decrease the output temperature by up to 4 °K. The combined use of double spiral fins and microencapsulated PCMs results in a 7.5 % improvement in the efficiency of the heat exchanger and the coefficient of performance of the heat pump. This study highlights the potential of innovative design modifications and material enhancements to significantly improve GSHP performance for more efficient and sustainable heating and cooling solutions.

CHARACTERIZATION AND SI ENGINE TESTING OF GASOLINE AND BLENDS OF GASOLINE AND BIOETHANOL PRODUCED FROM CO-FERMENTED WATERMELON AND PINEAPPLE WASTES

Industrial development and population growth are two key factors that have led to increased energy consumption. Conventional energy sources are fast becoming insufficient in matching the increased demands. Over the last two decades, a great interest in exploring alternative energy sources has been developed. Amongst the highly sought for alternatives to fossil fuel, biofuel has gained high recognition. In this research, bioethanol produced from co-fermentation of watermelon and pineapple waste using Saccharomyces cerevisiae was successfully studied and compared to standard values. Performance evaluation of the spark ignition (S.I) single cylinder, four stroke and air-cooled engine running on gasoline and bioethanol blends was analysed. The engine brake power, torque, exhaust gas temperature performance with E14 (blending 14% bioethanol with 86% gasoline) was found to be better than pure petrol at various load ranging between 500g to 3000g. The brake specific fuel consumption was however better with gasoline than the blends at various loads. The overall performance results showed that a blend containing 14% bioethanol, and 86% gasoline can be successfully used as petrol substitute without any modification in the available engine design.

Impact of Temperature Variations on Torque Capacity in Shrink-Fit Junctions of Water-Jacketed Permanent Magnet Synchronous Motors (PMSMs)

This study investigates the impact of temperature variations on the torque capacity of shrink-fit junctions in water-jacketed permanent magnet synchronous motors. Focusing on both baseline and improved designs; torque capacities were evaluated across a temperature range from −40 °C to 120 °C under different material conditions: Least material condition, nominal, and maximum material condition. The baseline design exhibited torque capacities from 7648 Nm to 9032 Nm at −40 °C, decreasing significantly to 549 Nm to 1533 Nm at 120 °C. The improved design showed enhanced performance, with torque capacities ranging from 8055 Nm to 9247 Nm at −40 °C and from 842 Nm to 1618 Nm at 120 °C. The maximum improvement was observed at 120 °C for least material conditions, with a 55.4% increase, and the minimum improvement at −40 °C for maximum material conditions, with a 2.4% increase. Our findings demonstrate a significant increase in torque capacity by up to 20% under varied thermal conditions. These results underscore the effectiveness of design modifications in enhancing thermal stability and torque capacity, making the improved design a more reliable choice for high-performance applications subject to significant thermal fluctuations. This research highlights the critical role of material selection, thermal management, and precise design adjustments in optimizing the performance and reliability of permanent magnet synchronous motors.

Enhanced water production and improving solar water distillation efficiency of double-slope solar stills: Modeling and validation

Solar distillation is a promising technology for producing clean water using renewable energy, especially in regions with water scarcity and contamination. This study investigates the impact of design modifications on the efficiency of a double-slope solar still coupled with evacuated tubes and external reflectors. Using Matlab software analysis, key findings indicate that packing factors, temperature control, and solar radiation exposure all contribute to the system’s optimal performance. Solar radiation levels directly correlate with production rates, emphasizing the need for effective sunlight exposure. The system’s ability to rely on stored heat at night enhances its practicality. This study shows how to make solar stills more efficient at producing clean water. It is found that the best way to do this is to use PV cells with a packing factor of 0.25. A packing factor of 0.25 outperforms other factors, significantly increasing water production and system efficiency. With this optimal factor, the system achieved a remarkable thermal efficiency of 83.5 % and a maximum daily production of 19 L per square meter during peak solar radiation hours. The system’s overall efficiency is 94 % increased by 13 % over the highest value recorded in previous studies. Furthermore, the system’s productivity increased by 40 % from the highest value recorded in previous studies. The amount of electrical energy produced is directly proportional to the packing factor, by the power of 41.1 W-hours (Wh) at a PV cell with a packing factor of 0.25.

The Applicat ion of Super Absorbent Polymer in Self-Healing Morta r: The Effect on Mechanical Properties

Super Absorbent Polymer (SAP) were used in various application, including in mortar production. The ability of SAP to absorb a high amount of water made this material become a promising water reservoir in the mortar that can later mitigate micro-cracks in concrete. Besides SAP, a nutrient must be embedded into self-healing mortar to support metabolism in bacteria-based self-healing mortar. However, adding SAP and nutrient was reported to decrease the mechanical properties of the resulting self-healing mortar. Thus, in this research, the modification in the mix design of mortar containing SAP and nutrient were observed. The water to cement ratio was decreased up to 0.3. The amount of SAP and entrained water added is based on its swelling capacity. The swelling capacity of SAP, the workability of fresh mortar, and the compressive strength of mortar were examined. The results show that the swelling capacity of SAP was affected by the pH and the presence of calcium ions in the solution. The higher the pH and the calcium ion in the solution, the lower SAP’s swelling capacity. Applying the modified mortar mix design containing SAP and nutrient proofed to mitigate the reduction in workability and compressive strength of the resulting self-healing mortar.

Advancing clinical trial equity through integration of telehealth and decentralized treatment.

Innovative strategies to increase clinical trial accessibility and equity are needed. We conducted a retrospective review of a phase II investigator-initiated trial to determine whether the modification of clinical trial design to decentralize study treatment can improve trial accessibility among underrepresented groups. Sociodemographic characteristics, including area deprivation indices, as well as study site travel distance, time, and costs were compared between enrolled participants who received chemotherapy locally and participants who did not. Participants who received chemotherapy locally lived substantially farther from the study site (median = 95.90 vs 25.20 miles, P = .004), faced a greater time burden traveling to the study site (median = 115.00 vs 34.00 minutes, P = .002), and had higher travel-related costs for a single trip to the study site (median = $62.81 vs $16.51, P = .004). This study highlights opportunities for alleviating financial and time burdens associated with clinical trial participation, promoting equity in clinical research. Trial Registration: ClinicalTrials.gov identifier: NCT04380337.

Commercial electric vehicle fleets in U.S. ancillary services markets: A stochastic analysis to inform utility rate design

For commercial fleets in the United States, traditional electricity tariffs can disincentivize vehicle-to-grid (V2G) participation and render electrification less attractive. First, we show that absent a rate redesign, opportunities for both fleets and the grid are missed. We propose a rate design modification: demand charge relaxation during off-peak (overnight) hours. This approach would enable fleets to shift additional load share to overnight hours and increase ancillary service revenues without the expectation of impacting local grid cost drivers (i.e., coincident peak load). Applied to a California case study, operational savings spanning 7.5% and 20.6% are realized via increased capacity revenues and deferred demand charges.

Multi-parameter similarity model-based lightweight design of battery electric vehicle body-in-white

The bending stiffness, torsional stiffness, and low-order modal frequencies of the body-in-white (BIW) are crucial factors in structural lightweight design. This paper introduces a BIW optimization approach for electric vehicles (BEVs) that integrates comprehensive sensitivity analysis and multi-parameter similarity models. The aim is to efficiently balance the BIW’s stiffness performance with minimal weight, while also managing potential manufacturing cost increases from design modifications. Firstly, the validity of the computational model is demonstrated by the BIW bending and torsion stiffness test and modal test. On this basis, the integrated sensitivity evaluation indexes of the structural member thickness parameters to the stiffness, weight and low-order modal frequency response of the BIW were calculated. The sheet metal thickness parameters of 17 structural members were preferred as design variables, and a multi-parameter similarity prediction model for BIW weight reduction design was constructed. Minimum weight, maximum stiffness and higher modal frequency of the BIW are defined as the optimization objectives. The optimal solution was finally solved using a multi-objective optimization algorithm. The results indicate a 1.582% reduction in weight of the BIW compared to the pre-optimization BIW. This paper delves into the intricate interplay between the parameters of the BIW’s structural components using simulation optimization techniques alongside experimental validation. This study not only proposes a new idea for the problem of how to efficiently and accurately determine the best optimization object from a large number of structural components in the development of vehicle structural safety, but also provides a research basis for automobile manufacturers to implement further weight reduction and optimization work on the BIW at the later stage of BEV development.

Experimental investigation of photo-thermal catalytic reactor for the reverse water gas shift reaction under concentrated irradiation

An upscaled photo-thermal catalytic reactor for the heterogeneously catalysed reverse Water Gas Shift (rWGS) reaction is tested under simulated concentrated irradiation. The reactor is equipped with an aperture of 144 cm2 area covered by a quartz window, where it receives irradiation flux densities of up to 80 kW/m2 corresponding to an irradiation power input of 1 kW thereby directly irradiating a RuO2 based photo-thermal catalyst that is deposited on a porous support. The system was operated under simulated concentrated sunlight for a total of 45.5 h with 35.4 h of chemical operation. A peak CO production rate of 1.6 mol/h was achieved with an average light concentration factor of 80 in the centre of the catalyst layer. This corresponds to a solar-to-chemical efficiency – defined by the ratio of the product of molar CO production rate and reaction enthalpy for the rWGS reaction and the irradiation power input – of 1.69 %. A calculation approach to determine the catalyst surface temperature under irradiation was introduced and utilised for performance analysis leading to the discussion of design modifications and operating strategies towards performance enhancement.

Fabrication and mechanical characterization of near field electrospun bioresorbable vascular grafts with fibrous architecture mimicking the arterial extracellular matrix

Cardiovascular disease, arteriosclerosis, is characterized by the thickening of blood vessel (arteries) walls restricting blood flow and is a global health problem. One treatment option is a surgical procedure utilizing an autologous or synthetic vascular graft to bypass or replace the diseased arterial segment. The goal of this study was to fabricate and mechanically characterize near field electrospun bioresorbable vascular grafts with a fibrous architecture that mimics the arterial extracellular matrix. Polydioxanone vascular constructs with circumferential fiber alignment angles of 15°/75° and 30°/60° (0° representing circumferential fiber alignment) were fabricated using a custom built near-field electrospinning (NFES) system. The vascular construct mechanical properties were compared to the saphenous vein (SV) and internal mammary artery (IMA) through longitudinal and circumferential uniaxial mechanical testing, suture retention, and burst pressure evaluations. The results demonstrated that the 15°/75° templates were closest to mimicking the native vessel target properties as compared to the 30°/60°; however, neither of the vascular template designs achieved or exceeded all the target values. For the ultimate tensile strength, both the constructs met the SV value on the circumferential axis (2.61 MPa) and the IMA value on the longitudinal axis (4.3 MPa). In terms of suture retention, the 15°/75° template was the only construct that was in the IMA and SV targeted range of 138–200 gf. Finally, the burst pressure testing results indicated that neither of the vascular constructs achieved the level of the SV or IMA (1600–3196 mmHg), however, the 15° constructs were within the lower error of the SV. In conclusion, with further design modifications, NFES constructs have demonstrated promise as small-diameter vascular grafts by mimicking native arterial architecture and mechanical properties.

Enhancing performance of Au-hyperdoped Si photodetectors for infrared detection

Hyperdoping Si with transition metals to form intermediate bands for infrared absorption has attracted attention recently for producing sub-bandgap photoconductivity. In particular, Si hyperdoped with Au has been demonstrated to exhibit optoelectronic response at 1550 nm. However, the reported external quantum efficiencies (EQEs) are low, and the device fabrication processes had not been optimized. In this paper, we demonstrate a significant improvement in sub-bandgap EQE through modification of the material and device fabrication processes. By increasing the Si:Au layer thickness, modification of device design, and formation of Ohmic contacts, the EQE was measured to be as high as 0.44% at 1550 nm, nearly two orders of magnitude higher than previous reports from similar devices. Additionally, the EQE was measured to be in the 10-3 range for wavelengths as long as 2.4 μm. The EQE spectrum showed features that were attributed to defect levels from a substitutional Au acceptor defect. The above bandgap EQE showed gain in one device. Thermal annealing at 300 °C does not improve the efficiency of Si:Au photodiodes. These results demonstrate the viability of Au-hyperdoped Si for infrared detection below the bandgap of Si.

Understanding and Design of Cathode–Electrolyte Interphase in High‐Voltage Lithium–Metal Batteries

AbstractThe development of lithium–metal batteries (LMBs) has emerged as a mainstream approach for achieving high‐energy‐density energy storage devices. The stability of electrochemical interfaces plays an essential role in realizing stable and long‐life LMBs. Despite extensive and comprehensive research on the lithium anode interface, there is limited focus on the cathode interface, particularly regarding high‐voltage transition metal oxide cathode materials. In this review, the challenges associated with developing stable high‐voltage cathode materials are first discussed. Characterization techniques for understanding the composition and structure of the cathode–electrolyte interphase (CEI) are then introduced. Subsequently, recent developments in electrolyte design and interface modification for constructing a stable CEI are summarized. Finally, perspectives on future research trends for understanding and developing the high‐voltage CEI are discussed. This review can offer valuable guidance for understanding and designing the high‐voltage CEI, pushing forward the development of high‐energy‐density LMBs.

Topological optimization and fatigue life prediction of a single pad externally adjustable fluid film bearing

This work focuses on the prediction and comparison of the fatigue life of topologically optimized pads in an externally adjustable fluid film (EAFF) bearing. It integrates one-way/two-way fluid–structure interaction analysis, topological optimization (TO), and design modifications of the pad of an externally adjustable fluid film bearing. The major goal is to create an optimum pad design that minimizes weight and maintains structural integrity, and then to predict and compare the fatigue life of these alternative designs. The outcomes of the present study are as follows: (i) Two-way FSI results show a decrease of 65.64% in hydrodynamic fluid film pressure when compared to one-way FSI results because they take into account modifications in the fluid region's geometry caused by pad deformation; (ii) even though the maximum pad deformation in optimized pad geometry (Type-4) resulting from oil film pressure is relatively small (0.0036551 mm), the influence of pad deformation on the fluid domain due to hydrodynamic fluid film pressure cannot be understated; and (iii) when comparing the TO technique's results with fatigue life results, four elongated holes in the radial direction (Type-4) are most appropriate.

Evaluation of gunshot injuries to long bones from pneumatic weapons using a human thigh model. Part I. Introduction and assumptions. Discussion of shot ballistics. Human thigh model.

In accordance with the Polish law, pneumatic weapons are weapons that use compressed gas to set a bullet in motion and generate a discharge energy of more than 17J. In recent years, Poland has seen an increase in crimes committed with pneumatic weapons. The research aim of the present study was to measure the velocity of selected 5.5 mm and 6.35 mm caliber shot and to create a model of a human thigh using a pig femur. This study used Air Arms Hi-Power Xtra FAC cal. 5.5 mm and FX Bobcat Mk II cal. 6.35 mm carbines and Haendler& Natterman's Spitzkugel, Hollow Point and Baracuda cal. 5.5 mm and 6.35 mm lead shot and Excite Apollo cal. 5.5 mm and Black Max Lead-Free cal. 6.35 mm lead-free shot. The velocity of the shot at a distance of 10 m was measured and its kinetic energy was calculated; pig femurs were measured and CT imaging was performed. The 5.5mm caliber shot reached velocities between 253 m/s and 278 m/s, obtaining energies between 27J and 44J. The 6.35 mm cal. shot reached velocities between 242 m/s and 254 m/s and energies between 52J and 59J. Pig femurs had an average weight of 410 g, a length of 239 mm, and a shaft diameter at mid-length of 30.6mm. The thickness of pig femur shaft walls was variable. A ballistic model of the human thigh was created using gelatin available in Poland. 1. The number of registered crimes with pneumatic weapons and the wide access to pneumatic devices with the possibility of design modifications justify the initiation of experimental studies on the assessment of gunshot injuries from pneumatic weapons. 2. The parameters of the shaft of a pig femur obtained from pigs weighing about 115 kg are similar to those of a human adult femur, which makes it possible to create a human thigh model. 3. Of the 5.5 mm cal. shot, the highest impact energies were generated by barracuda type shot, and of the 6.35 mm cal. shot, it was barracuda type and lead-free shot. 4. The thickness of the bony layer of the pig femur shaft is heterogeneous; the posterior wall of the shaft is the thickest, the lateral wall is the thinnest; however, it shows the greatest individual variability.

P‐220: A Novel Capacitive Touch Sensing Method with Folding Angle Detection using Foldable OLED TDDI Panel

This article presents a novel approach for detecting the folding angle (Of) of foldahle OLED TDDI panels using mutual capacitance driving. It offers the potential to reduce the number of module components, conserve space, and provide additional folding angle (Of) reference data for a wide range of applications. This method can be applied in self‐capacitive and mutual‐capacitive touch sensors, eliminating the need for additional sensors or design modifications.

Detecting cognitive impairment through an age-friendly serious game: The development and usability of the Spatial Performance Assessment for Cognitive Evaluation (SPACE)

The Spatial Performance Assessment for Cognitive Evaluation (SPACE) is a novel iPad serious game designed to identify differences in spatial ability indicative of early signs of cognitive impairment. This paper reports on the development of SPACE and presents the results from three usability studies across different ages. Study 1 compared the traditional tap and swipe control interface with a semiautomated interface. Study 2 investigated the benefits of a UI widget that displayed the rotation performed in the Virtual Environment (VE). Study 3 evaluated the effects of a simplified configuration of landmarks explored in the VE. Findings across the studies indicated that age was the primary factor influencing performance. Younger participants consistently outperformed older ones across various tasks and reported higher usability and lower workload. Despite notable performance improvements for the tasks in SPACE, the new control interface, UI widget, and simplified configuration only had a minimal impact on usability. Younger participants rated SPACE above the level of mature products, while older participants found it useable but not always engaging. Critically, the significant interactions between age and experimental conditions indicated that younger and older participants benefited differently from the design modifications. Here, the semi-automated control, the simplified configuration, and, to a lesser extent, the UI widget showed promise in mitigating age-related performance differences while maintaining the level of challenge necessary to assess differences in cognitive status. This research showcases the potential of SPACE as a serious game and emphasises the importance of balancing simplicity with task demands for future unsupervised deployment.

Drop breakup at reduced energy cost using a turbulent pulse –implications for improving efficiency in emulsification devices

Emulsification devices break drops by rapidly pushing them through a region of intense turbulence–a ‘turbulent pulse’. These devices are widely used in chemical engineering. However, the thermodynamic efficiency is low, and design modifications allowing more breakup at lower energy input is much in need.This study uses a combination of statistical models and direct numerical simulation coupled to high resolution interface tracking to investigate how a turbulent pulse should be designed to reach a desired breakup probability at minimum energy cost. It is concluded that breakup is not determined by the total energy input. Consequently, the energy cost of achieving a given breakup extent could be reduced by carefully tuning pulse amplitude and duration. The optimal pulse is compared to that delivered by homogenizers, revealing that the inability to dissipate turbulent kinetic energy in a sufficiently narrow region is partially responsible for the low efficiency.

Effect of Excess Air Ratio on Emissions, Performance and Efficiency of Gasoline Fueled Engines: A Review

In this paper, the fundamental aspects of the effect of excess air ratio (λ) on emissions and engine performance in spark-ignition engines are reviewed. The pollutants examined under both lean and ultra-lean conditions are oxides of nitrogen, unburned hydrocarbons and carbon monoxide. There is usually a range of fuel to air ratios beyond which ignition will not take place, hence, among the many techniques, some significant technologies that enable a leaner combustion mode in spark-ignition engines exist, which include modifications in the engine design, operating parameters and improvement of the fuels. In this paper, mainly the most prominent, up to date, and effective technologies such as ignition strategy, injection strategy, fuel blending, pre-chamber addition, are included. In addition to the effect the excess air ratio has on emissions, engine performance and efficiency are reviewed. This is done through the analysis of the Indicated Mean Effect Pressure, Coefficient of Variation, Fuel Consumption and Indicated Thermal Efficiency. The topics discussed relate to the primary categories listed above, but they are not exclusive to them. Finally, a conclusion and recommendations for future work are considered

Flow Simulation-Based Methodology for Reducing The Risk of Fuel Fire In An Aircraft’s Fuel System Enclosure

ABSTRACT This study applies advanced computational fluid dynamics (CFD) simulations to enhance the safety of an aircraft’s fuel system by striving to minimize the risk of on-board fire hazards. Employing a detailed flow simulation model, this research assesses the efficacy of newly designed measures within a fuel system, designed for a modified radial engine on a test-bed AN 2 airplane. The model simulates internal airflow, droplet particle flow, the formation of Eulerian Wall Film, and the vaporization process from the fuel film within the enclosure of the aircraft’s equipment bay. By exploring both the original and modified geometries of this fuel system enclosure, the simulations provide insights into the flowpaths of leaking fuel, the spatial and temporal distribution of fuel vapor concentrations, and the overall effectiveness of design modifications aimed at rapid removal of hazardous substances. Structural improvements, including the addition of strategic ventilation inlets and outlets, are proposed based on the simulation results to ensure rapid dispersion of vapors and minimal residual fuel, effectively reducing the potential for vapor ignition. This study thus underscores the potential of precise CFD modelling in identifying risks and developing robust fire hazard mitigation strategies in aviation fuel systems.