Bohdan Trembach, Bohdan Mordyuk, Michal Krbata
et al.
In this study, hardfacing and a flux-cored/self-shielded powder wire of the FCAW-S-90G13N4 type was employed to produce and investigate the deposits of high-manganese steel. The effects of high-frequency mechanical impact (HFMI) treatment on the microstructure, hardening, and scratch resistance of the deposits were studied to evaluate and predict the impact wear resistance of the hardfacing deposits under controlled impact load conditions. As observed by XRD, SEM, and nanoindentation, the microstructure of deposited metal comprised a soft austenite matrix, dispersed hard carbides, and an ε phase (~26 vol.%). The wear resistance is thus not controlled by carbides alone but arises from the synergistic action of a hard carbide network within a ductile matrix. HFMI resulted in twinning, an increase in dislocation density, a grown volume fraction of ε (>60%) and α′-martensite. The interaction between twins, martensites, and dislocations provides a double/triple increase in microhardness (from HV<sub>0.2</sub> = 2.78 GPa to HV<sub>0.2</sub> = 6–7.69 GPa). After HFMI, scratch tests showed lower restored depths of scratch tracks and a 36–68% deceleration in the wear rate regarding those of the initial deposit. The underlying wear mechanisms were assessed accounting for the SEM observations of the scratch track morphologies and a ‘counterbody penetration vs. shear stresses ratio’ map. The initial plastic deformation-related mechanism (wedge/pile-up formation) changed by HFMI to ploughing. The obtained results allow one to evaluate and predict the impact wear resistance of the hardfacing deposits under controlled impact load conditions.
Berend Denkena, Volker Böß, Klaas Maximilian Heide
et al.
In modern production, Wire Arc Additive Manufacturing (WAAM) is becoming an essential technology for manufacturing complex components. However, the complexity of planning such processes constrains their widespread use in production cycles. Using various numerical simulation approaches allows for the investigation of resulting geometries with respect to process parameters, reducing the need for experiment-based process planning. Similar to various subtractive processes, there is increased interest in integrating simulation approaches into digital twin applications for planning and optimization of WAAM processes. This requires dynamic geometry mapping and simulation time comparable to the process duration. In this paper, a numerical simulation employing a Dexel-based geometry representation and a model for single-bead geometry parameter prediction is investigated as a vital alternative to Finite Element Method (FEM)-based simulations. The focus lies on the accuracy of the simulated components with respect to the simulation settings, the time needed for it to complete, and the degree of compliance between the simulated and produced multi-layer structures. Using optimized simulation settings achieves an accuracy loss of under 7% due to geometry discretization, with a simulation time that is approximately 37% faster than the process duration. The simulated components closely correspond to the experimental ones in terms of width and height, with a volumetric similarity ranging from 63.3% to 88.8%.
Dusan Schreiber, Bruna Haubert, Cristiane Froehlich
et al.
A indústria de móveis representa uma atividade econômica tradicional com relevante impacto ambiental, caracterizada também pelo ritmo lento na adoção de tecnologias avançadas. A literatura científica aponta que diversas tecnologias da indústria 4.0 podem contribuir para maior eficiência produtiva e mitigação do impacto ambiental. Este estudo teve como objetivo verificar as contribuições da adoção do Big Data no processo de fabricação de móveis para mitigar o impacto ambiental. Além do estudo de caso único, utilizou-se abordagem qualitativa e coleta de dados por entrevistas com dez profissionais, observação participante e levantamento documental. Os resultados mostraram que a empresa adota o Big Data tanto para maior eficiência produtiva quanto para mitigar impactos ambientais, melhorando o controle da matriz energética, consumo de insumos e evitando/reduzindo retrabalho, controlando a movimentação interna e otimizando o espaço de armazenamento. Algumas aplicações da tecnologia foram consideradas viáveis tecnicamente, mas não economicamente, como no controle de consumo de água e efluentes, bem como na gestão de embalagens de polímero, reforçando a necessidade de registro sistemático de custos envolvidos para respaldar as decisões gerenciais.
Production management. Operations management, Production capacity. Manufacturing capacity
This paper presents the general framework of the problem and the basis for the proposed idea, which lies in the design of a new extrusion nozzle for fused-deposition 3D printing, featuring a variable orifice that enables adaptive extrusion control to improve printing properties such as material efficiency, printing speed, and localized control of mechanical properties. The working principle is controlled compression, via a linear actuator, of a silicone sleeve installed inside a metal jacket. Constrained by the metal jacket, the diameter of the silicone sleeve’s through-hole decreases with increasing compression. Three experiments were carried out to verify the functionality of the new nozzle design. The first two explored how the size of the nozzle orifice changes with movement of the linear actuator and the resulting silicone sleeve compression and decompression. In the third experiment, three sample parts were printed to demonstrate how the variable-orifice-size nozzle extruded PLA. The orifice diameter was set to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.4</mn></mrow></semantics></math></inline-formula> mm for the first condition, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.7</mn></mrow></semantics></math></inline-formula> mm for the second condition, and, in the third experiment, the first two conditions were combined. The orifice diameter was set to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.4</mn></mrow></semantics></math></inline-formula> mm for the first half of the object and then abruptly reduced to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.7</mn></mrow></semantics></math></inline-formula> mm for the second half. The prototype variable-orifice-size nozzle system demonstrated the potential of adaptive extrusion control for improved material efficiencies, faster printing times, and localized control of mechanical properties. However, it also revealed hysteresis of the silicone sleeve, a problem that must be addressed.
Anne-Marie Layher, Lisa Tewes, Felix Thumann
et al.
Research and development in the field of glass-based laser additive manufacturing continues to receive significant interest within scientific and industrial contexts. In particular, powder bed fusion by laser radiation (PBF-LB) enables the additive manufacturing of porous and vitrified, complex three-dimensional components. The present study investigates the glass morphology that can be achieved using PBF-LB for components made from alkali borosilicate glass. The investigations focus on the comprehensive analysis of the entire process window, including the characterisation of porous and molten glass morphology. In particular, the influence of different laser-beam diameters, which are achieved through defocusing, and the variation in volume energy density are examined in detail and compared with conventional shaping. It was determined that the process of mechanically stable shaping is constrained to temperatures above the softening temperature and relative component densities within the range of ρrel = 37.8…94.2%. Furthermore, it has been demonstrated that the process-related line-like energy input results in the formation of characteristic vitrification strands. This research contributes to the overall understanding of the producible glass morphology and the process limitations of the PBF-LB process. In addition, the entire range of glass morphologies, ranging from open-pored to closed-melt configurations, could be analysed for the first time.
Ida Ketut Kusumawijaya, Partiwi Dwi Astuti, I Made Hedy Wartana
et al.
Tegalalang Village in Gianyar, Bali, is recognized for its intricate wall décor craftsmanship, which significantly contributes to the local economy. However, craftsmen encounter challenges in innovation capability, market expansion, and business sustainability. This study aimed to enhance their innovation capacity through skill development, business strategy training, and digital adaptation to strengthen competitiveness and ensure industry sustainability. A participatory action research approach was implemented, involving 12 craftsmen in structured workshops and hands-on mentoring. The methodology encompassed a pre-test assessment of innovation capability, capacity-building interventions focused on product development, production efficiency, and digital marketing, followed by a post-test evaluation. The innovation capability instrument framework guided the assessment, addressing key aspects of manufacturing, sustainability, and business management. Findings demonstrated substantial improvements across all ten dimensions of innovation capability. Post-test results indicated enhanced knowledge in optimizing production processes, adopting digital marketing, and utilizing sustainable materials. The mean innovation capability score increased, affirming the program’s effectiveness. However, challenges persist in financial support, digital adoption, and global market expansion. This study underscores the value of structured innovation training in empowering SMEs in traditional industries. Future initiatives should emphasize long-term mentorship, financial access, and market expansion strategies to sustain innovation-driven growth.
Aleksandr Voronov, Carmen Bachiller, Álvaro Ferrer
et al.
This paper presents three realizations of a complete set with a horn antenna and a focusing Gradient Index (GRIN) lens in X-band. The set was specifically designed for advancing additive manufacturing (AM) of polymers with different materials and techniques. The set has three constituent parts: a horn antenna, a support, and a lens. The horn antenna is the active element and must be electrically conductive; it was manufactured with Rigid10K acrylic resin and subsequently metallized using an electroless process. The support needed to be light, robust, and electrically transparent, so that Polyamide 11 (PA11) was used. The lens realization was intended for a dielectric material whose permittivity varies with its density. Therefore, the dielectric permittivity and loss tangent of different polymeric materials used in AM at 2.45, 6.25, and 24.5 GHz were measured. In addition, stochastic and gyroid mesh structures have been studied. These structures allow for printing a volume that presents porosity, enabling control over material density. Measuring the dielectric characteristics of each material with each density enables the establishment of graphs that relate them. The sets were then manufactured, and their frequency response and radiation diagram were measured, showing excellent results when compared with the literature.
Alireza Vahedi Nemani, Mahya Ghaffari, Khashayar Morshed-Behbahani
et al.
This study investigates the impact of incorporating TiC and TiB<sub>2</sub> inoculants on the microstructure and corrosion performance of an arc-directed energy-deposited PH 13-8Mo martensitic stainless steel. The microstructural characterizations revealed partial dissolution of the incorporated ceramic-based nanoparticles, resulting in the formation of in situ TiC phase in the TiC-inoculated sample, while TiC and chromium-enriched M<sub>3</sub>B<sub>2</sub> phases were formed in the TiB<sub>2</sub>-inoculated sample. Further investigations into the electrochemical response of the fabricated samples confirmed that the applied inoculation strategy slightly enhanced the corrosion resistance of the alloy, offering a valuable advantage for in-service performance for applications in harsher environments. The slight improvement in the corrosion resistance of the inoculated samples was found to be attributed to the formation of a higher fraction of low-angle grain boundaries and enhanced retained austenite content in the microstructure. However, it is essential to note that the formation of chromium-enriched M<sub>3</sub>B<sub>2</sub> phases in the TiB<sub>2</sub>-inoculated sample led to a slight deterioration in its corrosion resistance compared to the TiC-inoculated counterpart.
Md. Shahnewaz Bhuiyan, Ahmed Fardin, M. Azizur Rahman
et al.
The growing interest in sustainable and biodegradable materials has prompted significant attention towards natural fiber-reinforced composites (FRC) due to their lower environmental impacts. In a similar sustainable vein, this study fabricated composite materials utilizing bagasse fibers with the 3D SLA (Stereolithography) printing method. To start with, a novel fiber extraction process was adopted for extracting fiber from the bagasse stem in three distinct methods (Process-1, Process-2, and Process-3). The fiber extraction process includes washing, sun-drying, manual collection of rind fibers, immersion of rind fibers in NaOH at specific concentrations for specific durations, combing, and drying. In Process-1, the rind fibers were immersed in 5% NaOH for 15 h, while in Process-2 and Process-3, the rind fibers were immersed in 1% NaOH, but the soaking time varied: 25 h for Process-2 and 18 h for Process-3.for 25 h, and in Process-3, the rind fibers were immersed in 1% NaOH for 18 h. The resulting bagasse fibers underwent comprehensive property assessment with a focus on functional group analysis, diameter measurement, and tensile strength assessment. Subsequently, these fibers were used to fabricate composite materials via the 3D SLA printing technique after being treated in a NaOH solution. The Fourier Transform Infrared (FTIR) Spectroscopy results clearly showed that a fraction of hemicellulose and lignin was removed by NaOH, resulting in improved tensile strength of the bagasse fibers. Three-dimensional-printed composites reinforced with bagasse fibers extracted through the P1 method showed the highest improvement in tensile strength (approximately 70%) compared to specimens made from pure resin. The lack of pores in the composite and the observable fiber fracture phenomena clearly indicate that 3D printing technology effectively enhances the quality of the interface between the fiber and the matrix interfacial bonding, consequently resulting in improved tensile properties of the composites. The 3D-printed composites reinforced with bagasse fiber showcased impressive tensile properties and provided solutions to the limitations of traditional composite manufacturing methods. This sets the stage for developing innovative composite materials that combine natural fibers with cutting-edge fabrication techniques, offering a promising path to tackle present and future economic and ecological challenges.
A semiconductor distributor that plays a third-party role in the supply chain will buy diverse components from different suppliers, warehouse and resell them to a number of electronics manufacturers with vendor-managed inventories, while suffering both risks of oversupply and shortage due to demand uncertainty. However, demand fluctuation and supply chain complexity are increasing due to shortening product life cycle in the consumer electronics era and long lead time for capacity expansion for high-tech manufacturing. Focusing realistic needs of a leading distributor for semiconductor components and modules, this study aims to construct a UNISON framework based on deep reinforcement learning (RL) for dynamically selecting the optimal demand forecast model for each of the products with the corresponding demand patterns to empower smart production for Industry 3.5. Deep RL that integrates deep learning architecture and RL algorithm can learn successful policies from the dynamic and complex real world. The reward function mechanism of deep RL can reduce negative impact of demand uncertainty. An empirical study was conducted for validation showing practical viability of the proposed approach. Indeed, the developed solution has been in real settings.
Fatemeh Moheiseni, Seyed Aziz Arman, Seyed Amin Mansouri
In today’s world, countries have come to the realization that their available resources, including human capital, natural resources, and capital, are limited. To use these resources optimally requires that consumption be adjusted and productivity be increased. In this context, the labor force, as a fundamental factor in production, deserves special attention. Several factors such as geographical location, wages, welfare and health indicators, proximity, and population density can impact labor productivity. The present research aimed to investigate the impact of urbanization and its spatial spillovers on the productivity of provincial labor forces during 2006–2019, using the components of the human development index, urbanization rate, population density, and industrial wages. The study revealed the existence of spatial autocorrelation among the investigated provinces. The variables of human development index, urbanization rate, and industrial wage have direct and indirect positive and significant effects on provincial labor productivity, while the population density index has a direct positive effect and an indirect negative effect on labor productivity.IntroductionSustainable urbanization has been a fundamental component of the development of every country. Urbanization can have a significant positive impact on economic activities by providing better services, creating job opportunities, and increasing access to basic services. Cities have the ability to transform low-productivity agriculture into a high-productivity manufacturing industry and cost-effective service sectors. Cities in developing countries are the driving force behind economic growth, accounting for 70% of the gross national product (World Bank, 2009). With the increasing share of the population living in cities, improving the productivity of urban areas has become a priority for many governments and economic consulting organizations (OECD, 2016). Accordingly, cities possess the necessary ability and capacity to influence key economic factors. In this respect, the present study aimed to investigate the impact of urbanization on labor productivity, as a crucial factor for development, by evaluating the economic growth and examining several components of cities. The objective of research was to examine the spatial spillover effects of urbanization on labor productivity in Iran’s provinces, specifically focusing on the savings of density. The study tried to answer the following questions:Is it possible for an urban area to enhance labor productivity at the provincial level?Is there a relationship between labor productivity in a province and the direct and indirect effects of the provincial human development index?Are the external benefits of population density and urbanization (such as benefits from population increase and industrial concentration) responsible for this relationship?Is labor productivity affected by the direct and indirect effects (spillover) of industrial wages?Can the positive side effects of a more efficient urban economy in urban centers be affected by structural problems caused by rapid and dense population growth?Materials and MethodsThe basic model used in this study is as follows: The panel spatial econometric method was employed to analyze the spatial spillovers and geographic space involved in the impact of urbanization on provincial labor productivity. The Stata software was used to examine the final data, and a square matrix was created through GeoDa software in order to estimate the model with the spatial econometric method. This matrix represents the proximity between the provinces and assigns a value of 1 to neighboring provinces and 0 to non-neighboring provinces. Stata software packages were then used to standardize the provincial neighborhood matrix, and a vector was obtained by multiplying the matrix by the vector of each variable. The obtained vector was entered as an explanatory variable in the model, and its coefficient expresses the spatial effect. Based on the evaluated processes, the final model is as follows:+ ConclusionFirst, the estimated coefficients of the human development index and industrial wage of the labor force indicate that an increase in these factors within each province has a positive effect on labor productivity. Furthermore, the positive effects of these factors spill over into neighboring provinces. In this respect, competitive markets play a role in improving labor attraction factors within the province, thereby preventing the departure of skilled labor. With the implementation of necessary policies, job skills are promoted, and the permanent departure of highly skilled labor force is reduced.Second, the estimated coefficients of the urbanization variable show that the increase in urban population and demand, in addition to the training of specialized labor in cities, leads to the recruitment of skilled labor. This in turn has a positive spillover effect, increasing the urbanization rate of neighboring provinces. As a result, it leads to an increase in labor productivity in the neighboring provinces.Finally, the direct effect of population density in a province has a positive impact on labor productivity. However, the indirect effect of population density on labor productivity is complex. While creating a positive external effect due to economies of scale, the indirect effect is also countered by the crowding effect caused by population density. The crowding effect is actually due to the lack of sufficient infrastructure in line with population growth in the province, which leads to negative spillovers of neighboring regions into the province.The various effects observed provide strong evidence for a positive relationship between urbanization and labor productivity. These effects suggest that, under the appropriate conditions, cities have the potential to generate significant employment opportunities and stimulate growth and development not only within the city and province but also across the country. Cities can create sustainable jobs and increase productivity, thereby maximizing the ability to innovate, respond to market demand, and benefit from the advantages of dense markets.
Electrical resistivity was used in this test methodology to estimate the relative precipitate density in AA7075. Various electrical test parameters were explored to determine the difference between pulsed and DC-type currents. No difference between these test conditions could be distinguished. Furthermore, an electroplastic effect was not needed to explain these results and the effects are likely to be caused by purely joule heating.
Lucas Henrique Pereira Silva, Jacqueline Roberta Tamashiro
A busca pela qualidade na indústria da construção civil depara-se com os desafios no uso de insumos que atendam às normas vigentes. No Brasil, desde 2015 a comercialização de produtos cerâmicos deveria estar restrita às empresas que atendessem aos critérios de regulamentação técnica imposta pela Portaria nº 558/2013 do INMETRO. Entretanto ainda é muito comum encontrar materiais que não atendem as especificações. Assim, este trabalho avaliou a conformidade de blocos cerâmicos fabricados na cidade de Presidente Epitácio-SP. Foram analisadas as características gerais, geométricas, propriedades físicas e mecânicas dos tijolos cerâmicos das 5 empresas presentes no município. Com base nos resultados obtidos, concluiu-se que nenhuma das olarias cumpre todas as exigências da NBR 15270, sendo imperativo que se dedique esforços na padronização e implementação de controle durante todo o processo produtivo dos blocos cerâmicos, evitando assim o desperdício e diminuindo custos na construção civil.
Production management. Operations management, Production capacity. Manufacturing capacity
Marciel M. Oliveira, Francisco M. de Assis, Micael A. Dias
In this paper, we present a condition for the zero-error capacity of quantum channels. To achieve this result we first prove that the eigenvectors (or eigenstates) common to the Kraus operators representing the quantum channel are fixed points of the channel. From this fact and assuming that these Kraus operators have at least two eigenstates in common and also considering that every quantum channel has at least one fixed point, it is proved that the zero-error capacity of the quantum channel is positive. Moreover, this zero-error capacity condition is a lower bound for the zero-error capacity of the quantum channel. This zero-error capacity condition of quantum channels has a peculiar feature that it is easy to verify when one knows the Kraus operators representing the quantum channel.
Public managers lack feedback on the effectiveness of public investments, policies, and programs instituted to build and use research capacity. Numerous reports rank countries on global performance on innovation and competitiveness, but the highly globalized data does not distinguish country contributions from global ones. We suggest improving upon global reports by removing globalized measures and combining a reliable set of national indicators into an index. We factor analyze 14 variables for 172 countries from 2013 to 2021. Two factors emerge, one for raw or core research capacity and the other indicating the wider context of governance. Analysis shows convergent validity within the two factors and divergent validity between them. Nations rank differently between capacity, governance context, and the product of the two. Ranks also vary as a function of the chosen aggregation method. Finally, as a test of the predictive validity of the capacity index, a regression analysis was implemented predicting national citation strength. Policymakers and analysts may find stronger feedback from this approach to quantifying national research strength.
Mouli Chakraborty, Harun Siljak, Indrakshi Dey
et al.
In this article, we are proposing a closed-form solution for the capacity of the single quantum channel. The Gaussian distributed input has been considered for the analytical calculation of the capacity. In our previous couple of papers, we invoked models for joint quantum noise and the corresponding received signals; in this current research, we proved that these models are Gaussian mixtures distributions. In this paper, we showed how to deal with both of cases, namely (I)the Gaussian mixtures distribution for scalar variables and (II) the Gaussian mixtures distribution for random vectors. Our target is to calculate the entropy of the joint noise and the entropy of the received signal in order to calculate the capacity expression of the quantum channel. The main challenge is to work with the function type of the Gaussian mixture distribution. The entropy of the Gaussian mixture distributions cannot be calculated in the closed-form solution due to the logarithm of a sum of exponential functions. As a solution, we proposed a lower bound and a upper bound for each of the entropies of joint noise and the received signal, and finally upper inequality and lower inequality lead to the upper bound for the mutual information and hence the maximum achievable data rate as the capacity. In this paper reader will able to visualize an closed-form capacity experssion which make this paper distinct from our previous works. These capacity experssion and coresses ponding bounds are calculated for both the cases: the Gaussian mixtures distribution for scalar variables and the Gaussian mixtures distribution for random vectors as well.
Sony Suwasono, Shinta Syafrina Endah Hapsari, Ida Bagus Suryaningrat
et al.
The rapid competition between business and sustainability policy has encouraged the coffee industry in Indonesia to make their business more environmentally friendly. However, this initiative has yet to be fully underway. Several inefficiencies still prevail in Arabica coffee production sites, such as product defects in inventory, the inefficiency of production machine performance, and dependence on manpower that can increase the production and inventory costs. Therefore, the Arabica coffee agroindustry needs to improve its performance by addressing these issues in production activity using the lean manufacturing approach. Several tools proven influential to reduce waste in the agroindustry are Value Stream Mapping (VSM) and VALSAT. VSM could document the entire mapping of material and information management, but cannot classify the time required to complete the whole process. VALSAT has several derivative tools, but polyacrylamide (PAM) and Supply Chain Response Matrix (SCRM) are mostly used in agroindustry to classify value-added time of processes and illustrate the supply chain cumulative inventory of a company. The result of this study shows that the Indonesian Arabica coffee industry could reduce its cycle time by 57%, lead time by 63%, and changeover time by 50%. In addition, the recommendations result in the involvement of only 2 people during the drying process and eliminate the non-value-added time, while improving the overall production efficiency and capacity.
The Gaussian wiretap channel with rate-limited help, available at the legitimate receiver (Rx) or/and transmitter (Tx), is studied under various channel configurations (degraded, reversely degraded and non-degraded). In the case of Rx help and all channel configurations, the rate-limited help results in a secrecy capacity boost equal to the help rate irrespective of whether the help is secure or not, so that the secrecy of help does not provide any capacity increase. The secrecy capacity is positive for the reversely-degraded channel (where the no-help secrecy capacity is zero) and no wiretap coding is needed to achieve it. More noise at the legitimate receiver can sometimes result in higher secrecy capacity. The secrecy capacity with Rx help is not increased even if the helper is aware of the message being transmitted. The same secrecy capacity boost also holds if non-secure help is available to the transmitter (encoder), in addition to or instead of the same Rx help, so that, in the case of the joint Tx/Rx help, one help link can be omitted without affecting the capacity. If Rx/Tx help links are independent of each other, then the boost in the secrecy capacity is the sum of help rates and no link can be omitted without a loss in the capacity. Non-singular correlation of the receiver and eavesdropper noises does not affect the secrecy capacity and non-causal help does not bring in any capacity increase over the causal one.