Hasil untuk "Manufactures"

Ole S. Nesheim, Anni Cao, Lisa Ducarouge et al.

Anisotropy in fused filament fabrication of short fibre-reinforced polymer composites is mainly caused by uniform fibre direction and poor layer bonding. This study aims to improve the out-of-plane mechanical performance of carbon fiber-reinforced polyamide 6 parts by combining in-layer infrared postheating and a custom lifting toolpath designed to orient fibres in the out-of-plane direction. Single-walled samples manufactured with the lifting (L) and conventional toolpath (C) were printed at 1.2 and 3mm/s. Mechanical testing revealed an increased tensile modulus of 11.5% solely from the L toolpath. Compared to benchmark samples, an increase of 118.9% and 207.4% in ultimate tensile strength (UTS) and tensile modulus, respectively, was observed. Scanning electron microscope (SEM) images and crystallinity measurements indicated that while out-of-plane fibre rotation occurred within individual layers, it did not sufficiently bridge stacked layers to significantly impact UTS. The primary increase in UTS was thus attributed to enhanced matrix bonding due to postheating, while the L toolpath effectively increased the tensile modulus. Based on matrix structure variations observed in the SEM images, we hypothesize that the initially porous structure solidifying after material deposition can be effectively eliminated by postheating, resulting in increased interlayer contact area, ultimately enhancing UTS.

Paolo Ventura, Silvia Tosi, Flavia Dell’Agli et al.

Planetary nebulae, among the most fascinating objects in the sky, have been extensively investigated in the past years, because their study provides important information on the low and intermediate mass stellar populations of the host environment, formed earlier than ∼100 Myr ago. We report on the recent progresses achieved in the study of this class of objects, regarding the dust and gas content of the nebula, which allows us to reconstruct the dust formation process occurred during the previous asymptotic giant branch phase, and the chain of events occurred since the stars leave the asymptotic giant branch until the planetary nebula stage. The possibility offered by these studies to assess the role played by the stars of low and intermediate mass as dust manufactures in the Universe is also commented.

Ryan Banfi

This essay examines how Supreme reimagines skate culture and subculture through its adoption of Katsuhiro Ôtomo’s Akira. In doing so, this paper argues that Supreme manufactures subculture via reimagining established subcultural texts to further their concept of marginality– hypermasculine angry youth who rally against the mainstream by indulging in radical street skating/racing and dangerous drug use. By examining the relationship between Supreme and Akira, this paper offers an academic interpretation of a prominent understudied brand and a reading of Akira to suggest what the manga can mean in the current era of subculture. 

Maram Mahin, Nasser Kadasah, Abdullah Alsabban et al.

Quality 4.0 (Q4.0), integrates new digital technologies with traditional quality management to improve operational excellence across industries. This literature review, adhering to PRISMA principles, examines papers from 2015 to 2023, focusing on the benefits, challenges, and critical success factors of Q4.0 implementation. Results highlight significant benefits, including enhanced operational efficiency and innovation, while identifying skill gaps, restrictions on resources, and substantial expenses in investment as major challenges. Strategic leadership and comprehensive frameworks are essential for overcoming these challenges and facilitating successful Q4.0 implementation. These insights are intended to assist organizations in navigating the intricate landscape of Quality 4.0.

Thaise Regina Matos de Morais, Aloísio de Castro Gomes Júnior, Lasara Fabricia Rodrigues

O tempo de resposta de um Sistema Médico de Emergência (SME) é uma métrica preponderante de eficiência, visto que prestar atendimento rápido as vítimas de urgência, determina a minimização de sequelas permanentes ao mesmo tempo que maximiza a taxa de sobrevida do paciente. Neste artigo, propomos um modelo de simulação via otimização, desenvolvido em linguagem Python, capaz de avaliar o desempenho de SME’s. Aplicamos ao método proposto, os dados reais de um SME brasileiro e verificamos, a partir dos resultados obtidos, que configurações estratégicas resultariam na redução de aproximadamente 10% no tempo de resposta médio. Além disso, foi verificada a importância de se considerar outras variáveis de forma conjunta ao número de habitantes, na determinação do número de ambulâncias necessário para se atender as demandas de emergência no serviço pré-hospitalar.

Ali Mehboob, Imad Barsoum, Hassan Mehboob et al.

Implant designs highly influence their biomechanical performances when fixed with load-bearing long bone fractures. In this research work, the topology optimisation technique was used to obtain different shapes and designs of the bone plates according to three different loadings, e.g. lateral bending (LB), axial compression (AC), and physiological loads (PL), and solid volume fractions Vf of 30% and 70%. Bi-phasic mechano-regulation algorithm was used to investigate the callus healing for a given bone plate design, and stresses in screws and bone plates were monitored. To further validate the bone plate designs, fatigue analyses using Fe-safe and three-point bending tests were performed using additively manufactured plates. Topology-optimised bone plate PL with Vf 70% showed the maximum bending stiffness (peak load of 138 N and bending stiffness of 29 N/mm) among the optimised bone plates, with the best callus healing normalised stiffness of 0.6 and 0.7 in iterations 21 and 42, respectively. Thus, the bone plates produced using actual loading conditions (PL) outperformed other loading conditions during the biomechanical evaluation of fractured bones.

Yohan Wismantoro, MG Westri Kekalih Susilowati, Amalia Nur Chasanah et al.

Environmental damage and sustainability become the center of attention along with climate change today. One of the interesting things is the change in behavior in the consumption of products categorized as "green", including in terms of choosing tourism destinations. Environmentally friendly tourism destinations or ecotourism is increasingly becoming an option for those who care about the environment. Ecotourism is also used by many countries, including travel agents, to increase their economic value or profit. This study aims to investigate how the role of Environmental Concern as antecendent of Ecoturism Visit Intention mediates the influence of Future Time perspective and Destination Image toward Ecotourism visit Intention.  This research involved 200 respondents who had visited ecotourism destinations at least twice, which was obtained using a convenience sample approach. The data were analyzed using Structural Equation Modelling (SEM) which were processed using the SmartPLS 4.0 statistical package. The result shows that Future Time perspective and Destination’s Image positively impact Ecotourism Intention.   Future Time perspective and Destination’s Image also influence Ecotourism Intention indirectly through Environmental Concern as the mediating variable. As an implication, the government and travel agents improve service readiness and perception of high-value propositions to develop a better destination image.

Tworek Katarzyna

The article aims to show that reliable IT support was crucial for the survival and sustainability of organisations during the COVID-19 pandemic. The article considers the negative effect of the crisis caused by the COVID-19 pandemic on the organisational sustainability of an organisation (i.e., organisational performance through employee job performance). It explores the role of IT reliability in mitigating such a negative effect. To verify the hypotheses, the empirical studies were performed during the COVID-19 crisis with 1160 organisations operating in Poland, Italy and the USA. The data were analysed using multiple linear regression models with mediators and moderators. The results confirmed that due to the ability to limit the severity of a crisis-induced negative effect on employee job performance (influencing organisational performance), IT reliability could be considered a mitigator for the negative effect of the COVID-19 crisis on the sustainability of organisations. The results indicate that IT reliability should be fostered among organisations operating during the COVID-19 pandemic to maintain sustainability.

Claudia Noemí Zárate, Alejandra María Esteban, María Betina Berardi et al.

Abstract This study proposes a methodology that integrates Weighted Goal Programing with the Fuzzy Analytical Hierarchy Process to obtain the product mix in a multi‐bottleneck system. The problem is approached by analysing a case of a company that manufactures four products that must pass through six workstations. The opinion of four specialists involved in the decision is considered and goals are set contemplating profit maximisation, the balance between workstations, exploitation of bottleneck resources and customer satisfaction. The prioritisation of these objectives is obtained through the Fuzzy Analytical Hierarchy Process. This methodology takes into account the uncertainty in the evaluation of the experts. From its application, a single crisp vector is obtained, which is transformed into the weights of the goals. The result is a product mix that satisfies the goals, corresponding to the experts' opinions.

Ivanov Oleksandr, Prysyazhnyuk Pavlo, Lutsak Dmytro et al.

In this work was established that serial traditional hardfacing materials based on the Fe-Cr-C system are not effective for improvement of abrasion resistance of elements of equipment for production of bricks, solid fuel briquettes and for restoration of augers, due to the fact that this equipment works at significant specific and cyclic loads. Features of the coarse-grained structure of Fe-Cr-C based coatings leads to intensive abrasive wear. The aim of this study was to increase a durability of that equipment by using of flux cored electrodes with reaction components of Ti, Cr, Mo, B4C and their combinations to provide synthesis, which leads to fine-grained structure of refractory borides and carbides and their solid solutions with increased hardness. Structure of the hardfacing coatings were investigated by method of metallography, scanning electron microscopy (SEM), electron backscatter diffraction (BSD) mode and energy dispersive X-ray spectroscopy (EDS). Temperature dependences of equilibrium phase amount of the hardfacing materials were calculated by the CALPHAD technique, using JMatPro software. It was investigated that the offered materials are characterized by higher wear resistance at high specific and cyclic loads in comparison with serial production high-chromium hardfacing materials (Lastek, ESAB, Paton IEW). It was established that the abrasion wear resistance at high specific and cyclic loads depends mostly of formation of the structure of hardfacing material, and not the hardness. Also, using of powders of pure metals and their combination as reaction mixture for FCAW leads to fine structure which contains of refractory borides and carbides and their solid solutions.

Rozmus Magdalena, Dobrzaniecki Piotr, Siegmund Michał et al.

Dynamic development of 3D printing technology contributes to its wide applicability. FDM (Fused Deposition Method) is the most known and popular 3D printing method due to its availability and affordability. It is also usable in design of technical objects – to verify design concepts with use of 3D printed prototypes. The prototypes are produced at lower cost and shorter time comparing to other manufacturing methods and might be used for a number of purposes depending on designed object’s features they reflect. In the article, usability of 3D printing method FDM for designing of technical objects is verified based on sample functional prototypes. Methodology applied to develop these prototypes and their stand tests are covered. General conclusion is that 3D printed prototypes manufactured with FDM method proved to be useful for verifying new concepts within design processes carried out in KOMAG.

Qing-song Yan,, Gang Lu, Gui-ming Luo

The effect of synergistic action of ultrasonic vibration and solidifi cation pressure on tensile properties of vacuum counter-pressure casting ZL114A alloys was studied systemically through testing and analyzing the tensile strength and elongation subjected to different ultrasonic powers and solidifi cation pressures. The results indicate that the synergistic action of ultrasonic vibration and solidifi cation pressure can result in the refi nement of grains and improvement of tensile properties. Both the highest tensile strength and elongation of aluminum alloy were obtained under synergistic action of 600 W ultrasonic power and 350 kPa solidifi cation pressure. Moreover, the tensile fracture morphology shows obvious ductile fracture characteristics. When the solidifi cation pressure is lower than 300 kPa, the effect of ultrasonic power on tensile strength and elongation is more obvious, but when the solidifi cation pressure is higher than 300 kPa, the effect of solidifi cation pressure on tensile strength and elongation is greater. Meanwhile, the size and morphology of the eutectic silicon were improved signifi cantly by the ultrasonic vibration and pressurized solidifi cation. The strip and massive eutectic silicon phase are completely converted into small short rod-like and evenly distributed Si phases at the grain boundary of primary α-Al.

S. A. Sillars, C. J. Sutcliffe, A. M. Philo et al.

Residual stress is a major problem for most metal-based laser powder bed fusion (L-PBF) components. Residual stress can be reduced by appropriate build planning and post-process heat treatments; however, it is not always avoidable and can lead to build failures due to distortion and cracking. Accurate measurement of residual stress levels can be difficult due to high equipment set-up costs and long processing times. This paper introduces a simple but novel method of measuring residual stresses via a three-pronged cantilever component, the three-prong method (TPM). The method allows for a quick and easy characterisation of residual stress for a wide range of machine parameters, build strategies and materials. Many different cantilever designs have been used to indicate residual stress within additive manufacturing techniques. All of which share the same shortcoming that they indicate stress in one direction. If the principal component of stress is not aligned with the beam geometry, it will underestimate peak stress values. A novel three-prong design is proposed which covers two dimensions by utilising three adjoined cantilever beams, a configuration which echoes that of hole-drilling where three measurements are used to calculate the stress field around a drilled hole. Each arm of the component resembles a curved bridge-like structure; one end of each bridge is cut away from the base plate leaving the centre intact. Deformation of the beams is then measured using a co-ordinate measurement machine. Stress profiles are then estimated using finite element analysis by meshing the deflected structure and forcing it back to its original shape. In this paper, the new TPM is used to compare the residual stress levels of components built in Ti–6Al–4V with different hatch patterns, powers and exposure times.

Anislei Santiesteban-Velázquez, José Marcos Gil-Ortiz, Pedro Dionisio Remedios-Castañeiras et al.

El trabajo presenta la actualización del sistema de gestión de energía en la Universidad de Las Tunas “Vladimir Ilich Lenin”. Se analizaron los resultados de la actualización del Sistema de Gestión Total Eficiente de Energía y las medidas tomadas para el uso eficiente de la energía eléctrica. Se determinan las principales variables universitarias influyentes en el consumo y se realizó un estudio estadístico de las mismas. Se determinaron las áreas y puestos claves que inciden en el consumo de la energía eléctrica, siendo este el portador energético más consumido.

W.D. Wanrosli, I. Mazlan, K.N. Law et al.

The effect of acetosolv pulping variables viz. pulping time, temperature, catalyst (HCl) and acetic acid on oil palm frond fibres was investigated. The following conditions were found to be optimum to pulp frond fibres: 140 ºC, 0.5% HCl, 75% acetic acid, and 1/10 solid/liquor ratio. Under these conditions we could obtain these properties: Kappa number 13-16, zero-span tensile breaking length – 83 km, sheet density – 0.57 g cm-3, tensile index – 48 N m g-1, tear index – 5.4 mN m2 g-1, brightness – 16% ISO and opacity – 98%. Higher values of these operating parameters would degrade the fibre characteristics such as zero-span tensile breaking length, tensile index, and sheet density.

Yan-ling Zhang, Jianbo Chen, Yu Lei et al.

Moshe Syrquin, H. Chenery

P. Krugman

L. Winters