Hasil untuk "Production capacity. Manufacturing capacity"

Rui F. V. Sampaio, João P. M. Pragana, Guilherme P. Joaquim et al.

This paper examines the applicability of the fracture forming limits (FFLs) derived from conventional monotonic upset compression tests for assessing the formability of non-monotonic strain loading paths. The work uses a simple test specimen subjected to various non-monotonic deformation histories, and combines experimental force measurements, digital image correlation, finite element analysis, and scanning electron microscopy (SEM) to characterize strain loading paths and crack opening mechanisms under varying testing parameters. Results demonstrate that non-monotonic strain loading paths can result in fracture strains that differ from those obtained through conventional monotonic bulk formability tests in the effective strain versus stress triaxiality space, depending on the considerations made in the transition between different loading stages. Consequently, reliance on monotonic test data may lead to inaccurate predictions of cracking in multi-stage industrial bulk forming processes.

Mohsen Barmouz, Bahman Azarhoushang, Wolfram Kintzel et al.

In the original publication [...]

Petar Jevtic, Ahmad Varvani-Farahani

The present study intends to evaluate the ratcheting of ER9 wheel medium carbon steel and austenitic steel samples at room and elevated temperatures subjected to uniaxial loading cycles through the use of the Ahmadzadeh–Varvani (A–V) kinematic hardening rule. The A–V framework incorporated an exponential function in the dynamic recovery term to account for the dynamic strain aging (DSA) phenomenon at temperatures where solute atoms and moving dislocations showed increased interaction. Within the DSA domain at 573K for ER9 wheel steel samples, and at 423K for austenitic steel samples, the collision of carbon and nitrogen solute atoms with moving dislocations resulted in the materials hardening, and promoted the yield strength. The Voyiadjis–Song–Rusinek (VSR) multivariable model was used to capture the evolution of yield strength with temperature. The predicted ratcheting results within the DSA temperature domain were in close agreement with those of measured values.

Ashleigh Donaldson

This thesis explores factors influencing participation in voluntary capacity development. It emphasises how these factors are interrelated to ultimately drive someone to participate, or steer away from, engaging in capacity development both generally or for specific types. Prior literature focused on training and development has considered this primarily through a quantitative methodology, but less research has examined this from a qualitative perspective. By undertaking qualitative research on the matter, the thesis seeks to address this topic more broadly and provide a foundation for future quantitative research to further explore it. Within New Zealand, recent governments have been pushing for the generation of greater impact from the funding they invest in research. It has been argued, though, that such impact is less likely unless researchers have the capacities to progress their research beyond its technical base (Daellenbach et al., 2017). Such capacities are not part of typical training or employment requirements. Investigating this from the perspective of those who both have and have not participated in capacity development, this thesis sampled early-career science academics at Te Herenga Waka – Victoria University of Wellington. This enabled consideration of voluntary non-technical development (such as soft skills) in a primarily technically-focused situation. A semi-structured interview process was conducted, with sixteen early-career academics and two experienced researchers interviewed. These interviews gave the opportunity for participants to share their perspectives and reflect on their own and others’ participation in voluntary capacity development. The findings reveal that participation was not driven by a single factor, but rather a complex interaction of influences that extend beyond those identified in quantitative models. This allowed for the generation of a systems model which explained the virtuous (or vicious) nature of participating in capacity development, which can affect current and future participation. The findings also highlight that the relevance of the capacity development opportunities is a key factor that other aspects feed into or combine with to influence participation indirectly. Theoretically, these findings suggest that the specific type of development needs to be considered, as key factors such as relevance and workshop characteristics are associated with non-voluntary development decisions. This study also enhances existing models by recognising dynamically interacting characteristics that align with a systems perspective. Practically, these findings provide a foundation for understanding and addressing the challenges faced by early-career academics. There are benefits for research organisations, as catering to the needs around timing, communication, support, resourcing can be seen to enhance participation rates.

Huihuang Fang, Shuxun Sang, Zhangfei Wang et al.

Niccolò Grossi, Flavio Lazzeri, Giuseppe Venturini

Dot-by-dot Wire and Arc Additive Manufacturing (WAAM) is a promising technique for producing large-scale lattice structures, offering significant benefits in terms of deposition rate and material utilization. This study explores strategies for fabricating bar intersections using the dot-by-dot WAAM technology, focusing on creating robust and predictable structures without requiring parameter modifications or real-time monitoring during the deposition. Two different deposition strategies were proposed, that can be, at least geometrically, applied to a general intersection with multiple bars with different angles. In this work such strategies were only experimentally tested on two-bar intersections, assessing their performance in terms of geometrical accuracy, symmetry, and material efficiency. Strategies which utilize layer-by-layer deposition with multiple overlapping dots, called B here, demonstrated the best results in terms of the geometrical features in the intersection zone, assessed by different metrics obtained through an analysis of pictures, such as low asymmetry and high material volume in the intersection zone. In addition, the findings suggest that removing cooling pauses during the deposition of multiple dots on the same layer slightly improves the joint by minimizing excess material buildup. The proposed approach offers a scalable framework for optimizing intersection deposition, paving the way for improved large-scale metal lattice structure manufacturing.

Lei Cai, Han Zhao

During the Gas Metal Arc Welding (GMAW) process, intense arc light and dense fumes cause local overexposure in RGB images and data loss in point clouds, which severely compromises the extraction accuracy of circular closed-curve weld seams. To address this challenge, this paper proposes a multimodal fusion method for weld seam extraction under arc light and fume interference. The method begins by constructing a weld seam edge feature extraction (WSEF) module based on a synergistic fusion network, which achieves precise localization of the weld contour by coupling image arc light-removal and semantic segmentation tasks. Subsequently, an image-to-point cloud mapping-guided Local Point Cloud Feature extraction (LPCF) module was designed, incorporating the Shuffle Attention mechanism to enhance robustness against noise and occlusion. Building upon this, a cross-modal attention-driven multimodal feature fusion (MFF) module integrates 2D edge features with 3D structural information to generate a spatially consistent and detail-rich fused point cloud. Finally, a hierarchical trajectory reconstruction and smoothing method is employed to achieve high-precision reconstruction of the closed weld seam path. The experimental results demonstrate that under severe arc light and fume interference, the proposed method achieves a Root Mean Square Error below 0.6 mm, a maximum error not exceeding 1.2 mm, and a processing time under 5 s. Its performance significantly surpasses that of existing methods, showcasing excellent accuracy and robustness.

Ren Zhongxin, Yang Xiaoping, Chang Dawei et al.

Underground gas storage (UGS) is the most economical and effective means to guarantee stable gas supply. During gas production process, the evaporation of formation water leads to the increase of water content in the gas, and the salinity of the remaining formation water increases. This work applied numerical simulation to analyze the effect of salt deposition on flowing bottomhole pressure, production capacity and storage capacity. The simulation results show that the minimum and maximum pressure of UGS is more likely to be reached during multi-cycle production under the conditions of salt deposition. Under the initial water condition, reservoir drying can improve the gas storage capacity. At the end of the tenth cycle, the storage capacity increases by 1.4%. It is concluded that the study on the impact of formation water evaporation on storage capacity is helpful for the prevention and control of salt formation water in UGS with high salinity.

Laurent Spitaels, Endika Nieto Fuentes, Edouard Rivière-Lorphèvre et al.

The performance assessment of additive manufacturing (AM) printers is still a challenge since no dedicated standard exists. This paper proposes a systematic method for evaluating the dimensional and geometrical performance of such machines using the concept of machine performance. The method was applied to an Ultimaker 2+ printer producing parts with polylactic acid (PLA). The X and Y axes of the printer were the most performant and led to narrower potential and real tolerance intervals than the Z axis. The proposed systematic framework can be used to assess the performance of any material extrusion printer and its achievable tolerance intervals.

Marcos Vido, Athos Paulo Tadeu Pacchini , Wagner Cesar Lucato et al.

Tradicionalmente, a manufatura se baseava em uma economia linear, extraindo, fabricando, utilizando e descartando recursos, levando o planeta em direção à exaustão dos recursos. A Indústria 4.0 introduz tecnologias habilitadoras que podem promover estratégias circulares, enfrentando o desafio de reduzir o uso de recursos não renováveis. Este estudo modela um framework conceitual aplicando tecnologias digitais a uma economia circular, revisando sistematicamente a literatura específica utilizando a metodologia PRISMA. Os dados foram coletados por meio de estudos de caso envolvendo quatro empresas dos setores automotivo, eletrônico e de calçados. Os resultados confirmam a Internet das Coisas (IoT) e o Big Data como tecnologias cruciais para aplicações da economia circular. A integração bem-sucedida dessas tecnologias na Indústria 4.0 está prestes a melhorar a sustentabilidade industrial em vários setores de manufatura.

Widya Prapti Pratiwi, Riky Adhiharto, Muhammad Ilham Abdurrahman

Kendala utama yang dihadapi pada proses pengolahan umbi porang adalah keseragaman ketebalan chips porang dan kandungan kalsium oksalat yang tinggi. Umbi porang melalui tiga tahapan untuk dapat menjadi chips porang : pencucian, perajangan, dan perebusan. Rancangan mesin pada penelitian ini merupakan kombinasi dari mesin pencuci, perajang dan perebus. Cara kerja dari mesin ini adalah memasukkan umbi porang pada hopper, lalu porang mengalami proses pencucian dengan bantuan sikat pencuci yang berputar dengan gerakan translasi dari screw conveyor. Setelah itu umbi porang masuk ke ruang perajangan dengan output berbentuk chips. Selanjutnya chips tersebut direbus dengan larutan NaCl untuk mereduksi kandungan kalsium oksalat pada umbi porang. Penelitian ini menggunakan metodologi perancangan VDI 2222 meliputi merencana, mengonsep, merancang, dan penyelesaian. Proses perancangan dan validasi komponen kritis dilakukan menggunakan Software CAE (Computer Aided Engineering). Setelah melalui proses perancangan dihasilkan rancangan mesin dengan kapasitas produksi 500 kg/jam.

Fabio Giudice, Severino Missori, Cristina Scolaro et al.

Dissimilar welds between ferritic and austenitic steels represent a good solution for exploiting the best performance of stainless steels at high and low temperatures and in aggressive environments, while minimizing costs. Therefore, they are widely used in nuclear and petrochemical plants; however, due to the different properties of the steels involved, the welding process can be challenging. Fusion welding can be specifically applied to connect low-carbon or low-alloy steels with high-alloy steels, which have similar melting points. The welding of thick plates can be performed with an electric arc in multiple passes or in a single pass by means of laser beam equipment. Since the microstructure and, consequently, the mechanical properties of the weld are closely related to the composition, the choice of the filler metal and processing parameters, which in turn affect the dilution rate, plays a fundamental role. Numerous technical solutions have been proposed for welding dissimilar steels and much research has developed on welding metallurgy; therefore, this article is aimed at a review of the most recent scientific literature on issues relating to the fusion welding of ferritic/austenitic steels. Two specific sections are dedicated, respectively, to electric arc and laser beam welding; finally, metallurgical issues, related to dilution and thermal field are debated in the discussion section.

Julián David Rubiano Buitrago, Andrés Fernando Gil Plazas, Luis Alejandro Boyacá Mendivelso et al.

This research explores the utilization of powder fused filament fabrication (PFFF) for producing tungsten carbide-cobalt (WC-10Co) hardmetals, focusing on binder formulations and their impact on extrusion force as well as the influence of printing variables on the green and sintered density of samples. By examining the interplay between various binder compositions and backbone contents, this study aims to enhance the mechanical properties of the sintered parts while reducing defects inherent in the printing process. Evidence suggests that formulated feedstocks affect the hardness of the sintered hardmetal—not due to microstructural changes but macrostructural responses such as macro defects introduced during printing, debinding, and sintering of samples. The results demonstrate the critical role of polypropylene grafted with maleic anhydride (PP-MA) content in improving part density and sintered hardness, indicating the need for tailored thermal debinding protocols tailored to each feedstock. This study provides insights into feedstock formulation for hardmetal PFFF, proposing a path toward refining manufacturing processes to achieve better quality and performance of 3D printed hardmetal components.

Suhas Alkunte, Ismail Fidan, Vivekanand Naikwadi et al.

This paper thoroughly examines the advancements and challenges in the field of additively manufactured Functionally Graded Materials (FGMs). It delves into conceptual approaches for FGM design, various manufacturing techniques, and the materials employed in their fabrication using additive manufacturing (AM) technologies. This paper explores the applications of FGMs in diverse fields, including structural engineering, automotive, biomedical engineering, soft robotics, electronics, 4D printing, and metamaterials. Critical issues and challenges associated with FGMs are meticulously analyzed, addressing concerns related to production and performance. Moreover, this paper forecasts future trends in FGM development, highlighting potential impacts on diverse industries. The concluding section summarizes key findings, emphasizing the significance of FGMs in the context of AM technologies. This review provides valuable insights to researchers, practitioners, and stakeholders, enhancing their understanding of FGMs and their role in the evolving landscape of AM.

Zhicheng Liu, Yuan Li, Huazi Zhang et al.

In this paper, we establish the second-order randomized identification capacity (RID capacity) of the Additive White Gaussian Noise Channel (AWGNC). On the one hand, we obtain a refined version of Hayashi's theorem to prove the achievability part. On the other, we investigate the relationship between identification and channel resolvability, then we propose a finer quantization method to prove the converse part. Consequently, the second-order RID capacity of the AWGNC has the same form as the second-order transmission capacity. The only difference is that the maximum number of messages in RID scales double exponentially in the blocklength.

Toby Simon, Philipp Schumann, Michael Bieri et al.

Albumin solutions derived from human plasma have demonstrated clinical benefits as intravenous fluid therapy in clinical settings such as liver disease, sepsis, intensive care, and surgery. For all plasma-derived medicinal products, there is a potential risk from pathogens, including relevant blood-borne viruses, emerging viruses, and prion proteins. To minimize the risk of transmissible infections, the production of human albumin solutions includes rigorous donor selection and plasma testing, and effective pathogen removal and inactivation methods such as fractionation and pasteurization. Compliance with international pharmacopeial standards for purity and prekallikrein activator and aluminum content is crucial, as is post-marketing pharmacovigilance for the continuous monitoring of adverse events. This review focuses on the effectiveness of manufacturing methods in the production of plasma-derived albumin, to ensure the safety of hyperoncotic solutions for volume expansion. We evaluated evidence identified through online database (PubMed) searches and from unpublished sources, on the manufacturing and pathogen safety of plasma-derived albumin solutions. The results confirmed the already established and evolving pathogen reduction capacity of the reviewed manufacturing methods. Up-to-date post-marketing pharmacovigilance data and log10 reduction factors for known and emerging pathogens during albumin production are included. Towards the goal of ever-increasing clinical safety, potential areas of improvement, such as compliance rates for the completion of donor health questionnaires, are also discussed. Taken together, the current manufacturing and pathogen reduction steps result in albumin products of greater purity than previous-generation products, with a high margin of pathogen safety against known and emerging pathogens, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Joan Hernández

In the present paper we characterize the $(1/2,+)$-caloric capacity (associated with the $1/2$-fractional heat equation) of the usual corner-like Cantor set of $\mathbb{R}^{n+1}$. The results obtained for the latter are analogous to those found for Newtonian capacity. Moreover, we also characterize the BMO and $\text{Lip}_α$ variants ($0<α<1$) of the $1/2$-caloric capacity in terms of the Hausdorff contents $\mathcal{H}^n_\infty$ and $\mathcal{H}^{n+α}_\infty$ respectively.

Chaoyang Yu

With the rapid development of highland railways in China, a large amount of heavy metal wastewater was inevitably generated during the manufacturing process of alloy materials required for railway construction. In this paper, pyrolysis of municipal sludge was followed by ball milling to obtain ball milling sludge-derived biochar (SDBC), and then nZVI-loaded SDBC materials (nZVI@SDBC) were prepared by liquid-phase reduction. The effects of different factors on the Cr(VI) removal were investigated. The maximum Cr(VI) adsorption capacity of nZVI@SDBC(2:1) was 178.05 mg/g. The Cr(VI) removal process could be fitted by the Langmuir isotherm and pseudo-second-order kinetic model. The Cr(VI) removal mechanism mainly included complexation, reduction, electrostatic interaction, and coprecipitation. The Cr(VI) removal by nZVI@SDBC(2:1) was maintained at over 90% after five replicate experiments. nZVI@SDBC(2:1) was capable of removing most of the Cr(VI) from real electroplating wastewater. The cost of using nZVI@SDBC(2:1) to remove 1 m3 of actual wastewater is approximately 325.7162 USD/m3. This work provided a new idea for the solution of Cr(VI)-containing wastewater from the production of railway materials. HIGHLIGHTS The maximum Cr(VI) adsorption capacity of nZVI@SDBC(2:1) was 178.05 mg/g.; nZVI@SDBC(2:1) removed Cr(VI) from aqueous solutions by complexation, reduction, electrostatic interaction, and coprecipitation.; nZVI@SDBC(2:1) indeed achieved a Cr(VI) removal efficiency of more than 95% from real electroplating wastewater.;

Amir Dembo, Izumi Okada

We establish both the $\limsup$ and the $\liminf$ law of the iterated logarithm (LIL), for the capacity of the range of a simple random walk in any dimension $d\ge 3$. While for $d \ge 4$, the order of growth in $n$ of such LIL at dimension $d$ matches that for the volume of the random walk range in dimension $d-2$, somewhat surprisingly this correspondence breaks down for the capacity of the range at $d=3$. We further establish such LIL for the Brownian capacity of a $3$-dimensional Brownian sample path and novel, sharp moderate deviations bounds for the capacity of the range of a $4$-dimensional simple random walk.