Part Of Technology Research Articles

장애와 손상의 구분을 중심으로 본 장애의 모델들: 장애에 대한 다원적 접근의 필요성

The conceptualization of disability is not merely a descriptive issue but also a normative one, as the way disability is viewed can fundamentally shift the focus of what constitutes ethically appropriate support for disabled people. This paper reviews the historical debates surrounding models of disability over the past several decades, arguing that each model is a product of conceptual engineering, developed in response to normative needs related to disability. Given the persistent conflicts between these models, we propose a "pluralistic approach to disability" as a solution to the deadlock between them. It is argued that the conceptualization of disability does not require adopting a single stance among conflicting models; rather, by employing a pluralistic approach as part of strategic conceptual engineering, it becomes possible to more effectively address the diverse normative demands surrounding disability.

Rosalind Franklin Society Proudly Announces the 2023 Award Recipient for Tissue Engineering Part A.

Rosalind Franklin Society Proudly Announces the 2023 Award Recipient for Tissue Engineering Part A.

Pulsed electroplating of ZrO2-reinforced Ni-Cr alloy coatings from the duplex complexing agents-containing bath for engineering applications: Importance of operating conditions

The progress in tribocorrosion performance of the engineering parts is in dire need of improving their surface properties. In the present contribution, Ni-Cr-ZrO2 layers were electrodeposited on St37 steel. The stress was put on optimizing the process factors, including the parameters involved in pulsed current electrodeposition and level of the ZrO2 reinforcing nanoparticles (0–20 g/L) in the bath. The surface characteristics of the electrodeposits were evaluated using FESEM, EDS, AFM, and XRD. The tribomechanical characteristics of the films were determined using a Vickers microhardness tester and pin-on-disk apparatus. The electrochemical behavior of the samples was studied using OCP, EIS, PDP, and immersion techniques. The results demonstrated that the included ZrO2 nanoparticles led to more homogenous, rougher, and defect-free surfaces, while they did not change the phase composition of the alloy electrodeposits. The polarization resistance of the Ni-Cr alloy coating increases by 6.7 times when 10 g/L of the reinforcing nanoparticles is added to the electrolyte. A decrease of ≈42 % in the mean COF value was obtained by the incorporation of 10 g/L ZrO2 nanoparticles into the plating bath. The coating system developed holds the promise to address both technical requirements and health concerns.

Effect of the Addition of Cu and Al on the Microstructure, Phase Composition and Properties of a Ti-6Al-4V Alloy Obtained by Selective Laser Melting

The present study considers the samples of an Ti-6Al-4V alloy obtained by selective laser melting with the addition of a 10% Cu-Al powder mixture. The microstructure, elemental composition and phase composition, as well as the physico-chemical properties, have been investigated by the methods of electron microscopy, X-ray phase analysis, and bending testing. The obtained samples have a relative density of 98.5 ± 0.1%. The addition of the Cu-Al powder mixture facilitates supercooling during crystallization and solidification, which allows decreasing the size and changing the shape of the initial β-Ti grains. The constant cooling rate of the alloy typical for the SLM technology has been shown to be able to prevent martensitic transformation. The formation of a structure that consists of β-Ti grains, a dispersed eutectoid mixture of α-Ti and Ti2Cu grains, and a solid solution of Al in Cu has been revealed. In the case of doping by the 10% Cu-Al mixture, the physico-mechanical properties are improved. The hardness of the samples amounts to 390 HRC, with the bending strength being 1550 ± 20 MPa and deformation of 3.5 ± 0.2%. The developed alloy can be recommended for applications in the production of parts of jet and car engines, implants for medicine, and corrosion-resistant parts for the chemical industry.

Influence of heat treatment on the structure and mechanical properties of pseudo α-titanium alloy in a welded joint

The object of this study was the weld material of a new Ti-6.1Al-6.0Zr-6.3Sn-3.2Mo-1.1Nb-1.2Si alloy, which was obtained by electron beam welding. Electron beam welding (EBW) provides rapid melting and cooling with crystallization under significant temperature gradients. For the pseudo α-titanium alloy, this leads to the appearance of significant residual stresses in the joint and determines the specificity of the dispersion decay of the β-phase. Residual stresses are reduced by preliminary heating, removed by heat treatment. Such processing exerts a critical influence on the formation of the structure and phase composition of the weld and the zone of thermal influence of the electron beam; it can form macro defects, undesirable phases, and structural states. The conditions of heat treatment have been determined to bring the welded joint from complex alloyed pseudo α-titanium alloy to the required level of mechanical characteristics. The structure, phase morphology, elemental composition, and mechanical characteristics of welded joints without additional heat treatment have been compared, with preliminary local heating of 400 °C, with additional post-weld local annealing at ТТ=750 °С, tT=4 minutes and sequential annealing in the furnace at ТТ=850 °C, tT=60 minutes. It has been established that a full cycle of heat treatment of a welded joint provides the highest characteristics of strength and plasticity, but local heat treatment also makes it possible to obtain a defect-free joint with satisfactory characteristics for less responsible products. It is shown how heat treatment of pseudo α-titanium alloy makes it possible to get rid of unwanted phase formations (Zr,Ti)5Si3Al and transform them into (Zr,Ti,Nb,Mo)3SiAl. The results are promising for use in the production of aircraft engine parts

Construction Design of Slope Support Engineering in Water Conservancy and Hydropower Project

Slope support engineering is an important part of water conservancy and hydropower engineering, and its construction design plays a vital role in the safety and stability of the project. With the continuous development of water conservancy and hydropower project construction in China, the requirements for the construction design of slope support engineering are becoming higher and higher. Therefore, it is of great significance to deeply study and discuss the construction design of slope support engineering to improve the quality of the project and ensure the safety of the project. This paper mainly analyzes the construction design of slope support engineering in water conservancy and hydropower projects.

Devising a methodology for prototyping convex-concave parts using reverse-engineering technology providing the predefined geometric accuracy of their manufacturing

The object of this paper is the geometric accuracy of the acquired portrait from the 3D printed full-scale sample in the reduced size of the convex-concave parts compared to the correspondingly reduced ideal one. The subject of research is reverse engineering and additive technology for manufacturing convex-concave parts for mechanical engineering (ME). A new prototyping methodology for convex-concave parts of mechanical engineering objects has proposed. Underlying the methodology is the use of the scaled (by reducing in size) ideal portrait of the 3D scanned original part. The decision to start the production is made by comparing the geometry of the portrait acquired from the 3D printed sample in reduced size with the ideal one, provided that the values are within the tolerance range. The following results were obtained. A design and technological analysis of the blade of the pumped hydroelectric power station was performed, after which a 3D scanner and a 3D printer were selected. A 3D scan of the blade with the formation of a portrait in the STL format file was implemented, as well as its refinement into an ideal one. From the geometric features and shapes of the blade, as well as the technical characteristics of the 3D printer, the percentage of reducing the sample for printing (by 75 % of the original dimensions) was calculated. According to the rated dimensions of the original part and the reduced sample, the tolerance field was set for the size: 0.6 mm and 0.25 mm, respectively, at 12 quality of the part’s manufacturing accuracy. Inspection of the printed sample and comparison with the correspondingly reduced ideal portrait revealed a deviation from –0.123 to +0.120 mm, which is within the defined tolerance field for the manufactured reduced sample. The results of experimental studies confirmed the adequacy of the proposed methodology for prototyping the mechanical engineering parts and verified the theoretical foundations of reverse engineering for convex-concave parts of any large size by using a proportional reduction in the size of finished portraits

Multi-Stage Engineered Co-Free Li[Ni1-X-Y Ti x Al y ]O2 Cathode for High-Energy Li-Ion Batteries

Since the global blueprint for carbon net zero emissions has been drawn, a part of the internal combustion engine (ICE) market share of vehicles has been continually shifting toward electric powered public and personal transportation. However, the serious remaining challenges regarding the price and performance issues of lithium-ion batteries (LIBs), which are the primary power source for electric vehicles (EVs), have impeded the large-scale adoption of EVs. Solving the affordability issue of current layered cathodes requires reducing the reliance on Co, which is extremely expensive with supply uncertainty. The aim of developing Co-poor or Co-free cathodes has led to an interest in LiNiO2 (LNO).1 LNO is one of the most promising cost-effective Co-free cathodes for LIBs because the cathode can achieve a high specific capacity of over 250 mAh g-1 with a typical upper voltage of 4.3 V versus Li/Li+. However, its poor cycling durability and thermal instability make its practical use difficult.2 In this study, we propose a highly stable Co-free Ni-enriched layered cathode based on LNO through a new doping strategy that incorporates heteroelements at different doping stages, i.e., the introduction of Ti during Ni(OH)2 synthesis and doping excess amounts of Al during the lithiation step. In combination with cathode surface protection, i.e., electrolyte modification or cathode surface coating, the proposed cathode retains 72.0% of its initial capacity after 3,500 cycles, which is the state-of-the-art for Co-free layered cathodes. Reference s : [1] M. Bianchini, M. Roca-Ayats, P. Hartmann, T. Brezesinski, J. Janek, Angew. Chem. Int. Ed., 58 (2019) 10434-10458.[2] H.-J. Noh, S. Youn, C.S. Yoon, Y.-K. Sun, J. Power Sources, 233 (2013) 121-130.

Impact of Lean-Burn Combustor Flow on Nozzle Guide Vane Performance

Abstract In this paper we investigate the impact of lean-burn-representative swirl and temperature distortion on the aerothermal performance of fully-cooled high-pressure nozzle guide vanes (NGVs) from a modern aero-engine. Experiments were carried out in the Engine Component AeroThermal (ECAT) facility at the University of Oxford. This is a fully-annular warm-flow engine parts facility, designed to operate at engine-representative conditions of Reynolds and Mach number. Inlet profiles of swirl, turbulence, and non-dimensional total temperature were generated using a non-reacting combustor simulator. The NGV outlet flow was experimentally characterized at three downstream planes in experiments with and without lean-burn-representative inlet conditions. Area-survey measurements included distributions of whirl angle, kinetic energy (KE) loss, and non-dimensional total temperature. Experimental data is compared to computational fluid dynamics (CFD) simulations. Fully-featured NGV geometry (including film cooling holes and internal passages) was used, to account for internal cooling flow redistribution resulting from altered external loading. We show that lean-burn inlet conditions result in significant surface flow redistribution, relatively high levels of residual swirl in the downstream flow, and a small increase of integrated KE loss.

Transparent Migration from Datastore to Firestore

Datastore was one of Google's first cloud databases, launched initially as part of App Engine, and built over Google's internal Megastore database system. Firestore was launched in 2019, both a re-implementation of Datastore over Google's Spanner database system and a new, mobile and web-friendly Firestore API. Spanner was chosen as the storage engine of Firestore in particular for technical reasons---it provides unrestricted transaction capabilities, strong consistency guarantees, and other improvements over Megastore. To provide these improvements to all our customers, and simplify our overall system, a non-disruptive, zero-downtime migration was executed of all Datastore databases (stored in Megastore) to Firestore databases (stored in Spanner). This migration took a couple of years to design and plan, and about three to execute. This paper describes both the core engine for migrating databases, and various practical problems that were solved to make this journey successful. As of the writing of this paper, all (over one million) databases have been successfully migrated.

Impact of mustard biodiesel and clove oil additives on particulate matter emission and carbon deposition in diesel engines

Recent studies suggest that the world is facing an energy crisis due to the depletion of fossil fuel reserves. To combat this issue, researchers have turned to biodiesel, a renewable bioenergy source made from vegetable oils, microalgae, and animal fats. A recent study analysed engine parts’ particulate matter emissions and carbon deposition during the long-term use of mustard biodiesel and clove oil as antioxidants in a compression ignition engine. Three samples of fuels: DF (diesel fuel), B30 (30% mustard biodiesel and 70% DF), and biodiesel blended fuel with 3000 PPM in a single-cylinder CI engine. The use of 30% biodiesel in diesel fuel (B30) for the endurance test was based on a good mix. The engine was run for 100 h to investigate the particulate matter emissions and carbon deposition. The particulate matter emission data was collected every 25 h, and for carbon deposition, the engine’s fuel injector was turned off after 100 h of engine running. The results showed a reduction in particulate matter emissions of about 9.97%, 13.367%, 7.24%, 14.64%, 5.3%, 12.32%, 1.88%, and 7.99% for PM1, PM2.5, PM7, and PM10 in biodiesel blended fuel and biodiesel blended fuel with clove oil, respectively. The deposition of clove oil added to biodiesel blended fuel in the fuel injector has been reduced compared with the other fuels. Carbon deposition of the fuel injector was analysed through SEM and EDX tests, and the results showed that the carbon content in biodiesel blended fuel was lower than in diesel fuel. The deposition of clove oil added to biodiesel blended fuel in the fuel injector has been reduced compared with biodiesel blended fuel.

Modeling of Residual Stress During EDM of AISI 4340 for Marine Propulsion Application

This investigation is conducted to estimate the extent of residual stress induced in the workpiece when machined on EDM. The Residual stresses induced post machining a product can led to lower life and inadequate failures during service. AISI 4340 finds its applicability in propulsion parts of marine engine and thus chosen as the material for study. Tungsten-Copper is selected as material for tool. Response Surface Methodology (RSM) with Central Composite Design (CCD) is utilized preparing the trails using current, on-time of pulse, voltage, and duty factor as machine variables. X-Ray Diffraction (XRD) was performed to estimate the d-space lattice of machined as well as un-machined specimens. Furthermore, Scanning Electron Microscopy (SEM) was executed to analyze effect of residual stress on surface post machining. The model suggested that voltage and on duration were crucial factors for residual stress while duty factor and current were less influential. Residual stress in the machined surface results from gradual heating and cooling during machining. The developed model was predicted to be accurate through the validation test. The micro-cracks resulted from the thermal stresses developed during machining of the workpiece.

Rapid screening of creep resistance in additive manufactured Ti-6Al-4V alloy

In this study, rapid screening of creep resistance for additively manufactured (AM) materials is enabled using an accelerated creep test (ACT) called the dynamic negative stepped test (DNST). Additively manufactured components are on the rise in aerospace systems, particularly turbine engine parts. It can be challenging to identify the AM process parameters that correspond to high-temperature strength and creep resistance. Tests are needed that rapidly screen and qualify creep resistance. In DNST, the temperature is held constant, and the specimen is taken through a series of load holds from high to low. The DNST contains two distinct characteristics: (1) the hold duration for each step is “dynamically” controlled to ensure the minimum-creep-strain-rate is achieved at every step, and (2) the “descending” profile maximizes damage accumulation while remaining on the edge of instability. The DNST assesses a material's ability to resist creep damage accumulated across multiple deformation mechanisms. In this study, electron beam melted Ti–6Al–4V, built at six (6) directions: 0°, 30°, 45°, 60°, 90°, and V, is tested using a four-step DNST at 650 °C. Analysis of the minimum-creep-strain-rate (at each step), creep ductility, and rupture were performed. A strain energy density (SED) benchmark metric was established to rapidly screen and classify creep resistance using an “Ashby-like” plot that balanced energy dissipated and energy dissipation rate. The creep resistance was found to be ranked from V, 60, 45, 30, 90, and 0 in descending order. Microstructural and crystallographic characterization revealed grain refinement progressing from the strain-free to the high-strain regions, indicative of dynamic recrystallization (DRX). Further observations revealed that the material's energy capacity increased with the alignment of the grains' long axis and tensile direction.

Highway tunnel safety detection and management

Highway tunnel is an important part of highway engineering, and its safety detection and management play a pivotal role in the construction and maintenance process of the whole project. However, due to the particularity of the tunnel itself, the engineering quality is difficult to guarantee, and there are many safety risks. With the continuous development of China's traffic industry, there are more and more highway tunnel construction, so safety detection and management is particularly important.

Pengaruh Surfaktan Polysorbate dan Lesitin Pada Pelumas Minyak Goreng Terhadap Temperatur Mesin dan Daya

The development of the automotive world to date has grown rapidly, especially two-wheeled vehicles. Large temperature changes in lubricating oil viscosity, even if the value is too low, will reduce the lubrication of engine parts, increase friction between metals, and cause engine parts to heat up quickly. Efforts to control and overcome excessive engine heat can replace mineral-based lubricating oils with environmentally friendly and biodegradable lubricating oils. The purpose of this study is to determine the effect of using a mixture of cooking oil and surfactants C64H124O26 and C42H80NO8P as engine lubricants on the power and temperature produced by motorized vehicles. The independent variables of this research are RPM variation and mixture of pure cooking oil with lecithin and polysorbate surfactant (2.5%, 5%, 7.5%). The dependent variables are engine temperature and power. The control variables of this research are testing at room temperature, 4 stroke 125CC matic vehicle, and Raw Material using Palm cooking oil. The test method uses an infrared thermo gun for temperature and Dyno test for the highest power test on the type of Cooking Oil + Polyosrbate 7.5% with an average overall power of 5.872, then for the lowest temperature on the type of Cooking Oil + Polysorbate 2.5% with an average value of 86.2ºC.

Exploring copper corrosion inhibition in value added neem biodiesel: Evaluation by traditional and machine learning approaches

Neem seed biodiesel is an eco-friendly fuel, however, to minimize its corrosion on copper metal used in engine parts, ethyl acetate extract of Syzygium aromaticum flowers was tested as an inhibitor. Copper corrosion evaluation in biodiesel revealed an inhibition efficiency of 97.96 %. Corrosion at the operating temperature of diesel engine was predicted by machine learning - quadratic regression. Thermodynamics and spectral evaluations bring to light the adsorption of inhibitors on the metal surface for inhibiting the corrosion of copper metal immersed in biodiesel. Surface morphological studies revealed the protective nature of the copper metal corrosion. Quadratic Surface Vector Machine (SVM) algorithm classified the corrosion classes as low, medium, and high with an overall accuracy value of 94.6 %. The percentage of non-corroded area of copper metal specimen in biodiesel medium with the said inhibitor as estimated with quadratic SVM is 97.193 %. The research findings suggest that the ethyl acetate extract of S. aromaticum flowers has the potential to perform as an effective corrosion inhibitor for copper in biodiesel medium and revealed the potential of quadratic SVM machine learning algorithm in corrosion estimation and classification.

The current status and trends of oral bone regeneration materials: a bibliometric analysis from 1991 to 2023

Objectives: Due to the complexity and importance of oral bone structure, oral bone regeneration materials differ from those used in other parts of the body. To study the research trends and hotspots of oral bone regeneration materials, this paper conducts a bibliometric analysis of related papers from 1991 to 2023 (retrieved on 27 September 2023).Materials and methods: Using bibliometric methods, two visualization metric software, Citespace and VOSviewer, were used to analyze 1217 papers in SCIE, including paper analysis, author analysis, country and institution analysis, keyword analysis, and cited literature analysis.Results: (Alavi et al., Oral Surgery Oral Medicine Oral Pathology Oral Radiology, 2023, 136 (5), 554–68) The number of papers is generally increasing and gradually stabilizing; (Xia et al., Bioactive Materials, 2021, 6 (11), 4186–208) Buser D is the most influential author, while Jung, Ronald E has the highest number of papers and total citations; (Wagner et al., Stem Cells Translational Medicine, 2019, 8 (10), 1084–91) The United States has the highest number of papers and citation frequency. The University of Bern and the University of Zurich in Switzerland are not only the institutions with the most papers but also the institutions with the most collaborations with other institutions. (Gallego et al., T Engineering Part A, 2010, 16 (4), 1179–87) Many research directions have persisted for decades since their inception. The field of oral bone regeneration materials is constantly developing and improving. In recent years, the research direction in this field may mainly focus on the role of blood cells and proteins in bone regeneration. (Wang et al., Japanese Dental Science Review, 2022, 58, 233–48). In recent years, the types of cited literature mainly include barrier membranes, alveolar ridge augmentation, bone graft materials, histological examination, and in vivo animal experimental models.Conclusion: The United States and Switzerland have a significant influence in the field of oral bone regeneration materials. The research hotspot in recent years is mainly on tissue engineering materials. However, traditional materials still occupy a large proportion in clinical treatment or research. In addition, the combined use of new and old materials has gradually become one of the research hotspots in this field.

Determination of Indicators for Optimal Selection of Technological Operations when Repairing Parts of Aircraft Gas Turbine Engines

Determination of Indicators for Optimal Selection of Technological Operations when Repairing Parts of Aircraft Gas Turbine Engines

Advanced Automation Detection of Cracks in Railway Tracks

Abstract: India’s transportation infrastructure relies heavily identification. The integration of IR sensors enables the early detection of cracks on the track surface, allowing for the timely identification of potential structural weaknesses, on the Indian Railways, which serves as a major means of long-distance travel for millions. Nevertheless, the discoveryof cracks on railway tracks still poses serious problems that can compromise safety if not addressed. This paper thereforedescribes a path-breaking effort towards a strong crack detection mechanism in railways. Our unique way involves integrating infrared (IR) sensors for crack detection and ultrasound sensors for object detection to entirely change track monitoring thereby enhancing railway safety and maintenance efficiency. The system presented is able to detect any possible hazards within targeted area thus leading to prevention-based action through proactive maintenance; italso reduces cases of accidents as early detections helps in minimizing their chances of occurrence by making use of real-time data from these sensors. Our method demonstratesits effectiveness through experiments, showing that it can detect both cracks and blocking objects on the train tracks, hence contributing towards better rail safety systems while offering a promising direction for pre- emptive maintenanceprograms and risk control strategies. Our study proposes an innovative remedy for the current issue of security inclusion along railway tracks. Withthis combination involving IRs as well as ultrasonic sensors, our device has fulltime surveillance applications so that they are able to intervene timely before accidents are caused by this malfunctioning parts of the locomotive engines.

Study the Corrosion Behavior of Low Carbon Steel Weldments Immersed in Tap Water

Corrosion is one of the main sources of failure for metals and alloys, thus it is a major engineering problem. Engineers must consider the corrosion of metals in different environments when designing engineering parts. Metals tend to corrode in different media; they show different behaviors due to differences in chemical composition and the severity of the corrosive medium. In tap water, the corrosion of mild steel products is an electrochemical phenomenon that includes two reactions: the dissolving of iron (anodic) and the reduction of oxygen (cathodic). This work observes the corrosion behavior of welded low-carbon steel by Friction Welding (FW), Shielded Metal Arc Welding (SMAW) , and MIG welding techniques using immersion tests in tap water at different periods. The results revealed that while the corrosion rate of Base Metal (BM) increases, it reaches a nearly steady state in the friction-welded and SMAW-welded samples. The difference in the corrosion rate of the welded samples can be attributed to changes in the concentrations of Cl– and CaCO3 ,as well as the pH values of the corrosive mediums. Pits could be observed in the microstructure of the nugget zone for all weldments.