Hasil untuk "Production capacity. Manufacturing capacity"

Vilhelm Söderberg, Robert Tomkowski, Aleksandra Mirowska et al.

Machined surfaces contain rich information about machining conditions and system behavior and are typically assessed using off-line, small-area metrology. This study developed and validated an image-based methodology for process-oriented surface texture analysis of end-milled Spheroidal Graphite Iron (SGI), enabling scalable, non-contact monitoring suitable for in-line deployment. End milling trials were conducted under optimized and aggressive cutting conditions and in two orthogonal feed directions (X,Y). Surface topography from White Light Interferometry (WLI) was complemented by Charge-Coupled Device (CCD) microscope imaging. Image processing comprised automatic orientation correction, intensity profile extraction, and frequency-domain analysis via Fast Fourier Transform and power spectral density estimation. Texture metrics (RMS amplitude, skewness, kurtosis, dominant wavelength) were derived from intensity profiles, and two spectral indices were introduced: a Change Index (CI), capturing high-frequency content linked to process disturbances, and a Surface Anisotropy Metric (SAM), quantifying texture directionality. Aggressive cutting increased RMS by 28.5% and shifted skewness by 274% with strong statistical significance. Directional analysis showed 22% higher texture amplitude in Y than X, indicating axis-dependent machine behavior. CI correlated with the machining parameters and stability, while SAM reflected the machine and setup characteristics. Trends were consistent with WLI, supporting the method as a rapid, complementary tool for surface quality and machine condition monitoring.

José Luis Torres-Madroñero, Julian D. Osorio, Julián Sierra-Pérez et al.

Electricity production by concentrated solar power (CSP) systems has stood out among energy transition alternatives due to their large generation capacity (between 30 MW and 400 MW) and high capacity factor (80%) when incorporating thermal storage systems (TES). Although TES tanks in operation worldwide are made of austenitic steels with remarkable mechanical and anticorrosive properties, operational failures have been reported due to low-cycle fatigue, creep, and the abrupt release of residual stresses generated during tank manufacturing. A critical operation for salt tanks is the initial daily charging operation, given the low fluid level and the thermal gradients between the inventory and the salt entering the tank. This study presents a structural simulation of a 39.6 m-diameter molten salt tank for central receiver CSP plants, accounting for temperature and pressure variations during charging and different sparger ring inlet configurations. The initial pre-stressed condition of the floor, resulting from the manufacture of welded plates, is used as a boundary condition. The fatigue and creep life analyses were performed in accordance with the ASME BPVC and API standards. It was found that the tank’s floor is in a less favourable mechanical condition than the wall, due to its initial manufacturing condition and the maximum temperature differences during charging. A critical zone was identified in an area affected by residual stress on the floor and under the sparger ring. The baseline sparger ring configuration, with 52 2-inch-diameter orifices and a flow direction of 90°, results in an average floor stress of approximately 25 MPa and creep damage after 1.2 years of tank operation.

Eduardo Magdaluyo, Ariel Jorge Payot, Lorenzo Matilac et al.

This study evaluated the ballistic performance and failure mechanisms of epoxy-based hybrid laminates reinforced with abaca/UHMWPE and pineapple leaf fiber (PALF)/UHMWPE fabrics fabricated by using vacuum-assisted hand lay-up. Ballistic tests utilized 9 mm full metal jacket (FMJ) rounds (~426 m/s impact velocity) under NIJ Standard Level IIIA conditions (44 mm maximum allowable BFS). This experimental test was complemented by finite element analysis (FEA) incorporating an energy-based bilinear fracture criterion to simulate matrix cracking and fiber pull-out. The results showed that abaca/UHMWPE composites exhibited lower backface signature (BFS) and depth of penetration (DOP) values (~23 mm vs. ~42 mm BFS; ~7 mm vs. ~9 mm DOP) than PALF/UHMWPE counterparts, reflecting superior interfacial adhesion and more ductile failure modes. Accelerated weathering produced matrix microcracking and delamination in both systems, reducing overall ballistic resistance. Scanning electron microscopy confirmed improved fiber–matrix bonding in abaca composites and interfacial voids in PALF laminates. The FEA results reproduced major failure modes, such as delamination, fiber–matrix debonding, and petaling, and identified stress concentration zones that agreed with experimental observations, though the extent of delamination was slightly underpredicted. Overall, the study demonstrated that abaca/UHMWPE hybridcomposites offer enhanced ballistic performance and durability compared with PALF/UHMWPE laminates, supporting their potential as sustainable alternatives for lightweight protective applications.

Dedy Setyo Oetomo, Akhsani Nur Amalia

This study evaluates the technical and economic feasibility of establishing a 2 GWp solar-grade silicon wafer manufacturing facility in Batam Industrial Area, Indonesia. The proposed plant utilises Chinese-manufactured equipment for key processes, including 40 CZ Puller units, 20 Multi-Wire Saw units, and 15 CMP systems, with polysilicon as the primary raw material. A comprehensive analysis incorporating technical, financial, operational, and market aspects demonstrates project viability with an IRR of 18-20% and a payback period of 5-6 years. The total investment of USD 250 million encompasses equipment, infrastructure, and working capital. Results indicate favourable technical feasibility with established Chinese equipment manufacturers meeting international quality standards. Financial analysis shows strong potential returns, supported by growing regional solar panel demand and Batam's strategic advantages. Key risks identified include polysilicon price volatility, technological obsolescence, and market competition, with structured mitigation strategies proposed.

Sina Motamedi, Daniel R. Rousse, Geoffrey Promis

The increasing demand for sustainable building solutions has directed attention toward bio-based materials, among which mycelium bio-composites (MBCs) have emerged as promising alternatives to traditional insulation materials. Grown from fungal mycelium and lignocellulosic waste, MBCs offer low embodied energy, biodegradability, and effective hygrothermal performance. This review assesses the current state of the art in MBC fabrication and hygrothermal properties, encompassing both laboratory-scale and industrial methods. MBCs demonstrate thermal conductivity values in the range of 0.036–0.06 W·m⁻¹·K⁻¹, moisture buffering capacity comparable to plant-fiber composites, and up to 70% lower embodied carbon than conventional materials. Key challenges are identified, including process standardization, scalability, and durability under real-world conditions. These composites also offer moisture buffering, compostability, and design flexibility. Moreover, recent advancements in additive manufacturing and microstructural optimization suggest a path toward broader adoption of MBCs in construction. By highlighting critical technical and scientific developments, this review identifies targeted research priorities, including the development of standardized fabrication protocols, quantitative lifecycle assessment of MBCs across varying climates, and strategies to scale up production while maintaining mechanical and hygrothermal consistency.

Matjaž Kristl, Neža Zanjkovič, Jona Kunej et al.

In this work, we report on the mechanochemical preparation and characterization of binary (CdS, CdSe, and CdTe) and ternary (CdS_0.5Se_0.5, CdS_0.5Te_0.5, and CdSe_0.5Te_0.5) cadmium chalcogenides. The compounds were synthesized in a planetary micro mill using a zirconia grinding bowl and zirconia grinding balls. The products were examined by powder X-ray diffraction (pXRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), UV–Vis spectroscopy, and differential scanning calorimetry (DSC). Interestingly, CdO formed as a by-product only during milling of Cd+S and Cd+Se in air, while it was absent in the Cd+Te and all ternary systems. The materials were obtained in the form of irregularly shaped aggregates measuring up to several hundred nanometers, composed of nearly spherical primary nanoparticles with diameters in the 10–20 nm range. The band gap energies calculated using Tauc plots for CdS_0.5Se_0.5, CdS_0.5Te_0.5, and CdSe_0.5Te_0.5 were 2.01 eV, 1.72 eV, and 1.53 eV, respectively. These results demonstrate the expected tunability of band gaps in ternary cadmium chalcogenides and attest to the potential of such materials for semiconducting applications, particularly in solar cells. The mechanochemical approach is once again shown to be a simple and effective method for the preparation of both binary and ternary chalcogenides, avoiding the use of solvents, toxic precursors, and energy-consuming reaction conditions.

Nathan R. Hsieh, Aaron Guan, Saraswati Koul et al.

This study explores the enhancement of mechanical and adhesive properties of unsaturated polyester resins (UPR) through the incorporation of bio-derived chitin nanowhiskers (CNWs) into the polymer matrix. CNWs are high-performance nanoparticles extracted from chitin, an abundant and renewable biopolymer. The research investigates the effects of processing strategies and CNW loadings on the chemical structure, thermal behaviour, mechanical strength, and adhesive performance of UPR–CNW nanocomposites. CNWs were incorporated into the UPR matrix via slurry compounding using different suspension media, including ethanol, acetone, and methyl ethyl ketone, and through direct mechanical mixing with CNW dry powders. Experimental results show that the thermal and mechanical properties of the nanocomposites are highly sensitive to both the thermal history during processing and the choice of suspension medium. Most importantly, the optimal adhesive performance was achieved via slurry compounding with a CNW suspension in ethanol, following an evaporative pre-treatment of the suspension to reduce ethanol content and thereby minimize transesterification of the polyester matrix.

Christian Kuehn, Sara-Viola Kuntz

Neural Ordinary Differential Equations (Neural ODEs), which are the continuous-time analog of Residual Neural Networks (ResNets), have gained significant attention in recent years. Similarly, Neural Delay Differential Equations (Neural DDEs) can be interpreted as an infinite depth limit of Densely Connected Residual Neural Networks (DenseResNets). In contrast to traditional ResNet architectures, DenseResNets are feed-forward networks that allow for shortcut connections across all layers. These additional connections introduce memory in the network architecture, as typical in many modern architectures. In this work, we explore how the memory capacity in neural DDEs influences the universal approximation property. The key parameter for studying the memory capacity is the product $K τ$ of the Lipschitz constant and the delay of the DDE. In the case of non-augmented architectures, where the network width is not larger than the input and output dimensions, neural ODEs and classical feed-forward neural networks cannot have the universal approximation property. We show that if the memory capacity $Kτ$ is sufficiently small, the dynamics of the neural DDE can be approximated by a neural ODE. Consequently, non-augmented neural DDEs with a small memory capacity also lack the universal approximation property. In contrast, if the memory capacity $Kτ$ is sufficiently large, we can establish the universal approximation property of neural DDEs for continuous functions. If the neural DDE architecture is augmented, we can expand the parameter regions in which universal approximation is possible. Overall, our results show that by increasing the memory capacity $Kτ$, the infinite-dimensional phase space of DDEs with positive delay $τ>0$ is not sufficient to guarantee a direct jump transition to universal approximation, but only after a certain memory threshold, universal approximation holds.

Jingwei Li, Thomas G. Robertazzi

This paper explores the distribution of indistinguishable balls into distinct urns with varying capacity constraints, a foundational issue in combinatorial mathematics with applications across various disciplines. We present a comprehensive theoretical framework that addresses both upper and lower capacity constraints under different distribution conditions, elaborating on the combinatorial implications of such variations. Through rigorous analysis, we derive analytical solutions that cater to different constrained environments, providing a robust theoretical basis for future empirical and theoretical investigations. These solutions are pivotal for advancing research in fields that rely on precise distribution strategies, such as physics and parallel processing. The paper not only generalizes classical distribution problems but also introduces novel methodologies for tackling capacity variations, thereby broadening the utility and applicability of distribution theory in practical and theoretical contexts.

Perla N. Chávez-Dulanto, Oliver Vögler, Salomón Helfgott-Lerner et al.

The food security of Lima—Peru’s capital city, which shelters over 30% of the total country’s population—depends on the food production of its nearest agricultural areas, the Chancay-Huaral and Chillón valleys, wherein agrochemicals are widely used. This study primarily aimed to determine the characteristics of pesticide use in these two valleys, located 83 and 30 km north of Lima City, respectively. A second aim was to assess whether proximity to Lima provides access to technical assistance regarding agricultural activities. A questionnaire-based survey assessing socioeconomic aspects, occupational exposure, and agrochemical-related knowledge was conducted on a sample of 102 participants (farmers and fieldworkers). The results revealed that the average age for starting to handle pesticides was 15 years, while life-long occupational-exposure averaged 30 years. Most pesticides used were organophosphates and carbamates. Personal protective equipment was not used and, therefore, dermal exposure and inhalation were major routes of intoxication. Despite their proximity to Lima, both valleys lack an official agronomic advisory agency, and this void has been occupied by agrochemical manufacturing companies and trading houses focused on increasing their sales. Based on the results, it is urgent to implement an official technical advisory service and a capacity-building program on pesticide use in Peru, as well as the implementation of measures for improved control, trade, and storage of pesticides. Simultaneously, a permanent epidemiological surveillance at the country level is needed to improve public health and to contribute to achieving the Sustainable Development Goals of the United Nations’ 2030 Agenda in Peru.

David de Boer, Pjotr Buys, Jeroen Zuiddam

Determining the Shannon capacity of graphs is a long-standing open problem in information theory, graph theory and combinatorial optimization. Over decades, a wide range of upper and lower bound methods have been developed to analyze this problem. However, despite tremendous effort, even small instances of the problem have remained open. In recent years, a new dual characterization of the Shannon capacity of graphs, asymptotic spectrum duality, has unified and extended known upper bound methods and structural theorems. In this paper, building on asymptotic spectrum duality, we develop a new theory of graph distance, that we call asymptotic spectrum distance, and corresponding limits (reminiscent of, but different from, the celebrated theory of cut-norm, graphons and flag algebras). We propose a graph limit approach to the Shannon capacity problem: to determine the Shannon capacity of a graph, construct a sequence of easier to analyse graphs converging to it. (1) We give a very general construction of non-trivial converging sequences of graphs (in a family of circulant graphs). (2) We construct Cauchy sequences of finite graphs that do not converge to any finite graph, but do converge to an infinite graph. We establish strong connections between convergence questions of finite graphs and the asymptotic properties of Borsuk-like infinite graphs on the circle. (3) We observe that all best-known lower bound constructions for Shannon capacity of small odd cycles can be obtained from a "finite" version of the graph limit approach. We develop computational and theoretical aspects of this approach and use these to obtain a new Shannon capacity lower bound for the fifteen-cycle. The theory of asymptotic spectrum distance applies not only to Shannon capacity of graphs; indeed, we will develop it for a general class of mathematical objects and their asymptotic properties.

Ruslan Morozov, Tolga M. Duman

Particularly motivated by DNA storage channels, we consider channels with synchronization errors modeled as insertions and deletions, along with substitutions. We focus on the case where the synchronization error process has memory and investigate the information stability of these channels, hence the existence of their Shannon capacity. We assume that the synchronization errors are governed by a stationary and ergodic finite state Markov chain and prove that such a channel is information-stable, which implies the existence of a coding scheme that achieves the limit of mutual information. This result implies the existence of the Shannon capacity for a wide range of channels with synchronization errors, with different applications, including DNA storage. We also provide specific examples of deletion channels with Markov memory and numerically evaluate their capacity bounds, thereby allowing us to quantify the capacity difference between memoryless deletion channels and those with memory with the same deletion probability and reveal that having memory increases the channel capacity.

Slamet Wahyudi, Janitra Naufal Faza, Nafisah Arina Hidayati

Biogas adalah salah satu energi alternatif yang mempunyai nilai ekonomisnya besar teruntuk masyarakat pedesaan. Dalam prakteknya kandungan CH4 biogas menjadi bagian terpenting untuk proses konversi energi namun zat pengotor berupa karbondioksida yang menurunkan nilai kalor masih besar. Sehingga diperlukan upaya untuk menurunkan CO2 dengan proses purifikasi. Tujuan penelitian ini untuk mendapatkan cara purifikasi yang meningkatkan kualitas biogas dengan nilai kalor tinggi dan zat pengotor CO2 yang rendah. Penggunaan adsorben serbuk genteng jenis ukuran yaitu fine dan coarse, yang diteliti pada selang waktu 5 dan 20 menit, untuk pengambilan data nilai kalor dan kandungan CO2. Gas Chromatography – Mass Spectrometry (GCMS) digunakan pengujian kandungan gas hasil adsorbsi. Hasil penelitian menunjukkan jenis ukuran serbuk genteng yang lebih halus (fine) memberi hasil purifikasi lebih baik dengan hasil pada menit ke 5 dan 20 masing-masing sebesar 24,1 dan 20,1 % sementara pada jenis ukuran butir coarse pada menit ke-5 dan 20 masing masing menghasilkan kadar CO2 sebesar 23,1 dan 20,8%. Karena terjadi penurunan kadar CO2 maka nilai kalor biogas setelah purifikasi tertinggi bernilai 23893 kJ/m3 setelah proses purifikasi yang telah menghasilkan penurunan kadar CO2 diketahui selama proses purifikasi berlangsung efektivitas penyerapannya terbesar adalah 59,8 % pada jenis ukuran fine pada waktu 20 menit. Semakin halus ukuran serbuk genteng maka nilai kalor semakin meningkat.

Muhammad Dimas Ferdiansyah, Sukendra Sasongko

The Dwi Hasta lifting crew jack is a tool that assist the car maintenance mechanician. It tool support the car at an elevation for the maintenance working and lay it down after the mechanician done. The objective of study is to obtain the cost of the manufacturing from production stage to selling. In which, it device is for assisting the mechanician repaired a car. Manufacture system would obtain economic values and production time at one unit. The investigation is started from design, and to the manufacturing system. Regards to the planning of the manufacturing, the production cost, the selling cost, and time of refund are obtained at the cost calculation. The money refund is the production cost will get after selling. The experiment method is conducted at operating process chart (OPC), manufacturing lead time (MLT), production time, production flow, production capacity and break event point (Q). The experiment results showed economic value from raw material to one-unit machine. MLT is of about 53,83 hours. Production time performs is for 346,7 min. Production capacity is 6 units per month. Break Event Point (Q) will be started after 3 months. The profit taking back is Rp 6.181. 964. Money will be payback after 3 month.

Chen Zhang, Yang Yang, Jiahao Liu et al.

Pretrained language models (LMs) have shown compelling performance on various downstream tasks, but unfortunately they require a tremendous amount of inference compute. Knowledge distillation finds a path to compress LMs to small ones with a teacher-student paradigm. However, when the capacity gap between the teacher and the student is large, a curse of capacity gap appears, invoking a deficiency in distilling LMs. While a few studies have been carried out to fill the gap, the curse is not yet well tackled. In this paper, we aim at lifting the curse of capacity gap via enlarging the capacity of the student without notably increasing the inference compute. Largely motivated by sparse activation regime of mixture of experts (MoE), we propose a mixture of minimal experts (MiniMoE), which imposes extra parameters to the student but introduces almost no additional inference compute. Experimental results on GLUE and CoNLL demonstrate the curse of capacity gap is lifted by the magic of MiniMoE to a large extent. MiniMoE also achieves the state-of-the-art performance at small FLOPs compared with a range of competitive baselines. With a compression rate as much as $\sim$50$\times$, MiniMoE preserves $\sim$95\% GLUE score of the teacher.

Carlos Henrique Rocha, Felipe Amaral Costa

Em 2020, o Aeroporto Internacional de Natal, concedido em 2011, declarou falência e ingressou com pedido na Agência Nacional de Aviação Civil (ANAC) para a sua devolução. Alegaram-se incapacidade de servir a dívida programada e parte dos custos de prestação de serviços e manutenção. O infortúnio financeiro do aeroporto de Natal ainda não foi estudado. Esta brecha justifica este artigo. A avaliação do requerimento de falência pode servir de benchmark para a condução da política governamental de regulação de aeroportos. O objetivo deste artigo é avaliar se o aeroporto tomou a decisão estratégica acertada ao pedir a sua devolução. São analisadas as contas financeiras do aeroporto de Natal entre 2014 e 2019 com duas metodologias. Uma estática e outra dinâmica. Os dados foram extraídos do site da ANAC. A primeira usa indicadores financeiros clássicos e a segunda aplica conceitos da Engenharia Econômica. Conclui-se que a decisão foi acertada.

Muzi Tangyu, Michel Fritz, Lijuan Ye et al.

Abstract Background Sunflower seeds (Helianthus annuus) display an attractive source for the rapidly increasing market of plant-based human nutrition. Of particular interest are press cakes of the seeds, cheap residuals from sunflower oil manufacturing that offer attractive sustainability and economic benefits. Admittedly, sunflower seed milk, derived therefrom, suffers from limited nutritional value, undesired flavor, and the presence of indigestible sugars. Of specific relevance is the absence of vitamin B12. This vitamin is required for development and function of the central nervous system, healthy red blood cell formation, and DNA synthesis, and displays the most important micronutrient for vegans to be aware of. Here we evaluated the power of microbes to enrich sunflower seed milk nutritionally as well as in flavor. Results Propionibacterium freudenreichii NCC 1177 showed highest vitamin B12 production in sunflower seed milk out of a range of food-grade propionibacteria. Its growth and B12 production capacity, however, were limited by a lack of accessible carbon sources and stimulants of B12 biosynthesis in the plant milk. This was overcome by co-cultivation with Bacillus amyloliquefaciens NCC 156, which supplied lactate, amino acids, and vitamin B7 for growth of NCC 1177 plus vitamins B2 and B3, potentially supporting vitamin B12 production by the Propionibacterium. After several rounds of optimization, co-fermentation of ultra-high-temperature pre-treated sunflower seed milk by the two microbes, enabled the production of 17 µg (100 g)−1 vitamin B12 within four days without any further supplementation. The fermented milk further revealed significantly enriched levels of l-lysine, the most limiting essential amino acid, vitamin B3, vitamin B6, improved protein quality and flavor, and largely eliminated indigestible sugars. Conclusion The fermented sunflower seed milk, obtained by using two food-grade microbes without further supplementation, displays an attractive, clean-label product with a high level of vitamin B12 and multiple co-benefits. The secret of the successfully upgraded plant milk lies in the multifunctional cooperation of the two microbes, which were combined, based on their genetic potential and metabolic signatures found in mono-culture fermentations. This design by knowledge approach appears valuable for future development of plant-based milk products.

R. O. Santos, L. S. Santos, D. M. Prata

Abstract Nowadays the exploitation of conventional natural gas resources has been contributing to the problem of increasing CO2 concentrations in the atmosphere and consequently increasing the global warming. The natural gas accounted for a majority of the feedstock used for methanol manufacture. Nevertheless, in the next years, methanol will have to be produced from less polluting sources that release small quantities of CO2 and methane to the atmosphere. In this regard, the use of biogas for producing methanol appears to be a viable alternative. However, few studies have studied the optimization of methanol production plants from renewable sources. Thereby, the main purpose of this paper is to make a comparative analysis, throughout mathematical modeling and simulation, of different methanol production routes, by considering four biogas sources: landfill, palm oil effluent, corn cobs and sorghum fermentation. For all cases, an optimization study was performed, with the goal of maximizing the methanol production. The results evidenced that the biogas from palm oil showed to be the most profitable concerning the other sources. On the other hand, the landfill gas showed to be a very limited capacity for methanol supply. Finally, the process optimization indicate that the operating conditions must be adjusted with respect of the biogas composition, in order to allow the maximum production.

E. Fox, B. V. Sweet, Valerie Jensen

Juan Piñeros, Alyne Toscano, Deisemara Ferreira et al.

The datasets presented here were partially used in “Formulation and MIP-heuristics for the lot sizing and scheduling problem with temporal cleanings” (Toscano, A.,  Ferreira, D., Morabito, R., Computers & Chemical Engineering) [1], in “A decomposition heuristic to solve the two-stage lot sizing and scheduling problem with temporal cleaning” (Toscano, A., Ferreira, D., Morabito, R., Flexible Services and Manufacturing Journal) [2], and in “A heuristic approach to optimize the production scheduling of fruit-based beverages” (Toscano et al., Gestão & Produção, 2020) [3]. In fruit-based production processes, there are two production stages: preparation tanks and production lines. This production process has some process-specific characteristics, such as temporal cleanings and synchrony between the two production stages, which make optimized production planning and scheduling even more difficult. Thus, some papers in the literature have proposed different methods to solve this problem. To the best of our knowledge, there are no standard datasets used by researchers in the literature to verify the accuracy and performance of proposed methods or to be a benchmark for other researchers considering this problem. The authors have been using small data sets that do not satisfactorily represent different scenarios of production. Since the demand in the beverage sector is seasonal, a wide range of scenarios enables us to evaluate the effectiveness of the proposed methods in the scientific literature in solving real scenarios of the problem. The datasets presented here include data based on real data collected from five beverage companies. We presented four datasets that are specifically constructed assuming a scenario of restricted capacity and balanced costs.