Production Engineering Research Articles

Engine option in aircraft purchase: Company strategies and policy implications

Airlines select an aircraft's engine simultaneously while purchasing the aircraft. Usually, an aircraft model has multiple engine options, but recently the number of engine options has been decreasing. We develop a three-echelon supply chain model including engine manufacturers, aircraft manufacturers, and airlines to analyze the engine options in airlines' new aircraft purchases. We show that given an airline's existing fleet composition, larger fleet size and higher aircraft production efficiency would make it more likely to choose multiple engine options. In contrast, higher production costs and engine substitutability would lead to a shift to a single engine or hinder the airline's fleet expansion. In the model, we highlight the impact of MRO (Maintenance, Repair, Overhaul) costs with economies of scale on airline engine option decisions as well. In particular, our theoretical findings suggest that the airline would buy more aircraft that are the majority types in their existing fleets, thus crowding out the minority ones. Our findings provide a reasonable explanation for the homogeneity of engine options and provide policy implications regarding airline expansion and aviation supply chain development.

Simulation Model of One-Parameter Selective Assembly of Two Elements With Multivariate Set-Making

Analytical and simulation methods are used to model assembly processes and technological systems in order to determine and optimize their performance and functioning parameters. The first one, describes an object or process using mathematical relationships indirectly. Simulation modelling is one of the modern methods of production system experimental research, allowing to take the presence of various components in the system, nonlinear characteristics, non-determinism and dynamism of ongoing processes into account. This work is devoted to the simulation model development of the technological process of multivariate one-parameter selective assembly of two elements. Multivariate set-making is defined by generalized rules with a set of weights which elements are set the distribution of elements between sets of different types. Selectively assembled elements have parameters determined by the manufacturing stage, which are independent random variables with known probabilistic characteristics. It is assumed that the input-output relationship is linear with given coefficients, the set-making equations linking the numbers of selective groups and assembly sets are known. A simulation model of the assembly process was built in the GPSS World, which, in contrast to the known one, operates with multivariate set-making rules for the case of assembly of two elements. The model allows to determine the quantitative indicators of the assembly process, in particular, the probabilities of assembly set formation, work-in-progress and preliminary rejects. As an example, the process of multivariate set-making of two parts forming a precision engineering product is considered. The data of parts distributions of both types by selective groups before assembly are given, the technological process indicators are calculated. Based on the modelling results the advantages and disadvantages of the multivariate set-making process are outlined.

Unveiling the dissolution mechanism of calcium ions from CSH substrates in Na2SO4 solution: Effects of Ca/Si ratio

The decalcification behavior of calcium silicate hydrate (CSH) under sulfate attack poses a critical challenge to the long-term durability of cement-based infrastructure, yet understanding its underlying microscopic mechanisms remains elusive. This study employs molecular dynamics to compare the differences in calcium ion dissolution capability of CSH substrates with varying Ca/Si ratios under sulfate solution exposure. The results show that the dissolution amount and dissolution efficiency of Ca are positively correlated with Ca/Si, and the root cause depends on the basic structure of CSH. With the increase of Ca/Si, the electronegativity of CSH decreases, and the adsorption capacity and stability of cations weaken. Meanwhile, Ca ions are less limited by the silicate chain coordination, water molecules are more likely to invade the substrate interior and replace the Ca ions. This research aims to provide a molecular basis for cement production and durability applications in marine engineering.

An interdisciplinary overview on biochar production engineering and its agronomic applications

Biochar is a porous, carbon-rich material derived from the thermochemical decomposition of biomass materials. Biochars are suitable soil amendments that enhance soil properties and improve crop productivity. Biochar agronomic impact in soils depends on its physiochemical properties. Recent research has shown that feedstock type and pyrolysis temperature are the key factors influencing biochar physiochemical properties. However, an in-depth understanding of the biochar-soil-plant co-relationship governing biochar agronomic performance still needs improvement. A comprehensive overview of the effect of biomass and pyrolysis temperature on biochar properties, mechanisms governing biochar-soil interactions impact on agronomic indices, the long-term effect of biochar, and the viability of large-scale biochar agricultural systems have been discussed. The mechanisms governing the impact of temperature and biomass properties on biochar agronomic properties are different for low temperature (<500 °C) and high temperature (>500 °C). The agronomic benefits of biochar are dependent on biochar-soil-plant interaction mechanisms. The economic and financial feasibility of large-scale production of biochar is case-specific and makes business sense when all co-pyrolysis products are recovered and sold. Understanding biochar-soil-plant-climate interaction mechanisms is key to designing biochars to address specific agronomic needs and requires an interdisciplinary and multiscale approach. Future studies should focus on long-term co-relationships among biochar physiochemical properties, soil conditions, climate, and farm management.

Methods to mitigate the impact of work environment on the measurement of building surface temperature by unmanned aerial vehicle onboard thermal imaging system

With the widespread adoption of UAVs and compact infrared cameras, UAV infrared remote sensing technology has extensive applications in qualitative research fields such as finding thermal bridges and air tightness detection in construction projects, but less in quantitative research, mainly due to its large temperature measurement error. When measuring temperature with UAV-mounted thermal imaging cameras, factors such as operational wind conditions and operation methods, in addition to the inherent accuracy of the instrument, can introduce measurement errors. To investigate the impact of operational wind conditions on temperature measurements by UAV-mounted thermal imaging cameras, both field and laboratory experiments were conducted to analyze the error characteristics caused by wind conditions. Devices were designed to mitigate the impact of wind on temperature measurements, and their effectiveness was validated through experiments. Based on these findings, methods were developed for reducing the influence of wind conditions on temperature measurements in UAV operations. The results indicate that wind condition errors primarily affect the stability of temperature data. Under the influence of wind conditions, the temperature data recorded by thermal infrared cameras exhibit periodic and significant fluctuations, with a temperature difference of approximately 4.7 °C between the highest and lowest points within a single cycle, constituting the main source of measurement error. However, by following the prescribed measurement procedures, the temperature measurement error can be reduced by 32 %, from ±5 °C to ±1.6 °C, approaching the accuracy of tripod-mounted thermal imaging cameras. This establishes a foundation for quantitative research in low-altitude infrared remote sensing.

Design and Fabrication of an Electrical Sheet by Waste Wood Fibre Reinforced Functionalized Polypropylene Composite

Abstract Utilizing natural resources is essential for sustainable development and circular economy. Polymeric composites reinforced with natural fibers are now being used to design commodity, commercial and engineering products. This study develops eco-friendlier composites of waste wood fibre (WWF) reinforced maleic anhydride functionalized (MAF) polypropylene (PP) composite (WWF/MAF-PP) by the Palsule process by extrusion followedby manufacturing by injection moulding. An electric bulb / electrical round sheet has been designed and fabricated using WWF/MAF-PP composites by injection moulding as a replacement for the existing commercial plastic sheet.

Identification of corrosion nature using acoustic emission in representative scale samples

Monitoring corrosion is critically important across numerous applications, given its occurrence in key industrial sectors such as energy production, transportation, and civil engineering to prevent leaks and failures. Especially, determining the exact nature of corrosion phenomena could help planning specific maintenance operations, reducing costs and risks. Machine Learning methods have demonstrated capacities to discriminate corrosion phenomenona. An important step to create precise Machine Learning models is the quality of training datasets. With this goal in mind, this paper presents experiments performed on different metallic samples to create specific corrosion forms, respectively pitting and uniform corrosion to train a supervised model. This model is evaluated on 316L steel samples prone to endure both pitting and uniform corrosion. The usage of supervised learning is then discussed compared to other methods.

INNOVATIVE APPROACH TO ENSURING THE QUALITY OF GAS TURBINE ENGINE PARTS PRODUCED BY SELECTIVE LASER SINTERING FOR UAV

The research objects are gas turbine engines parts, manufactured using an innovative method of additive manufacturing – selective laser sintering. The main problem solved in this work is the low quality of the surface layer and the residual porosity of the parts obtained by this method, which significantly limits their operational characteristics and durability. As a result of the experimental studies, rational operating parameters of diamond smoothing were established. This allowed to significantly improve the surface quality and increase the operational characteristics of parts made of heat-resistant alloys INCONEL 718 and an intermetallic alloy based on titanium aluminide OX45-3ODS. The effectiveness of diamond smoothing is explained by local plastic deformation and compaction of the surface layer of parts under the influence of high contact pressures and temperatures. This leads to a significant reduction in surface roughness, an increase in the surface hardness due to strain hardening and a significant reduction in the size and number of residual pores. A characteristic feature of the obtained results is the ability to control the quality parameters of the surface layer by varying the diamond smoothing operating parameters – smoothing force, feed, radius, and geometry of the smoother's working part. The established regularities of the smoothing operating parameters have an impact on the quality characteristics of the surface. This information can be utilized in the development of highly efficient technological processes for the production and restoration of gas turbine engines, critical components of unmanned aerial vehicles, obtained through selective laser sintering. Implementing the elaborated technological recommendations will permit broadening the range of goods produced by additive manufacturing and enhancing their capacity and dependability during operation under conditions of cyclical loads and extreme temperatures.

Application of composite film materials for marking engineering products

Application of composite film materials for marking engineering products

Research of Modified Polyamide Waste Agglomerate: Regulatory Issues and Technological Features

In this article, a regulatory processes study and technological properties of polyamide waste agglomerate modification is carried out. The legal support issues for polymer waste management in Ukraine are considered, ways to improve the most problematic aspects in this area are proposed. The technological properties of polyamide-6 waste agglomerate modification processes were studied in order to improve its technological and strength characteristics. MW-PA CB10 masterbatch modifier impact on the polyamide-6 waste agglomerate technological and strength characteristics complex was studied. It was established that the best is polyamide-6 waste agglomerate with 2 % wt. of masterbatch MW-PA CB10. For this composition the impact strength is 43.5 MPa, breaking stress during bending is 126.4 MPa, tensile strength is 342 N and elongation at break is 117 %. It can be recommended for reuse in traditional fields of primary polyamide-6 to obtain engineering and technical products.

APPLICATION OF ELECTROLYTIC PLASMA HARDENING FOR IMPROVING THE PROPERTIES OF MACHINE PARTS MADE OF STEEL 45

This study examined the effect of electrolytic plasma hardening (EPH) on the properties of 45-grade steel, which can serve as an alternative to traditional heat treatment methods used before the release of finished products. The results of the experiments showed that the mechanical and operational properties of 45-grade steel significantly improved after the application of EPH. Steel 45, widely used in mechanical engineering and agricultural machinery production due to its strength characteristics and durability, demonstrated a significant increase in performance after treatment. It was observed that the properties of 45- grade steel improved considerably after applying electrolytic plasma hardening methods, with the hardness of the samples increasing by 3.1-3.62 times, and wear resistance improving by 7 times. Moreover, the study highlighted the economic efficiency of the proposed treatment method, showing that the introduction of EPH can lead to a significant reduction in material costs, extended product life, and improved environmental performance by reducing energy consumption and emissions. The use of a non-toxic 20% sodium carbonate solution in EPH contributed to the uniform distribution of electric current in the cell and allowed for achieving optimal cooling rates of the sample.

The Future of Genetic Engineering in Crop Improvement and Food Production

The Future of Genetic Engineering in Crop Improvement and Food Production

Effects of the Characterization Methods of Heptane Plus Components (C7+) on the Phase Behavior of Volatile Fluids

For reservoir fluids with strong volatile tendencies, such as gas condensate and volatile oil, the determination of the characteristic parameters of the equation of state has a great influence on the fluid phase behavior and subsequent reservoir engineering, production engineering, and surface facilities design calculations. However, the process of characterizing reservoir fluid lacks a unified and standardized procedure, and the methods are largely empirical and rather complicated. In this paper, three main stages are defined for the characterization of the equation of state parameters for these volatile reservoir fluids, including (1) determining the C7+ distribution, (2) calculating the equation of state parameters for the C7+ single-carbon component, and (3) lump components. The typical calculation methods in each step and their effects on the fluid phase behavior calculations are quantitatively analyzed and compared. Finally, the workflow and the suitable characterization methods for gas condensate and volatile oil phase behavior calculations are selected. The results show that C7+ distribution and C7+ single carbon component properties have a greater influence on the phase behavior prediction of condensate gas and volatile oil, while the lumping of C7+ single carbon component has relatively little influence.

Structure and evolution of alanine/serine decarboxylases and the engineering of theanine production.

Ethylamine (EA), the precursor of theanine biosynthesis, is synthesized from alanine decarboxylation by alanine decarboxylase (AlaDC) in tea plants. AlaDC evolves from serine decarboxylase (SerDC) through neofunctionalization and has lower catalytic activity. However, lacking structure information hinders the understanding of the evolution of substrate specificity and catalytic activity. In this study, we solved the X-ray crystal structures of AlaDC from Camellia sinensis (CsAlaDC) and SerDC from Arabidopsis thaliana (AtSerDC). Tyr341 of AtSerDC or the corresponding Tyr336 of CsAlaDC is essential for their enzymatic activity. Tyr111 of AtSerDC and the corresponding Phe106 of CsAlaDC determine their substrate specificity. Both CsAlaDC and AtSerDC have a distinctive zinc finger and have not been identified in any other Group II PLP-dependent amino acid decarboxylases. Based on the structural comparisons, we conducted a mutation screen of CsAlaDC. The results indicated that the mutation of L110F or P114A in the CsAlaDC dimerization interface significantly improved the catalytic activity by 110% and 59%, respectively. Combining a double mutant of CsAlaDCL110F/P114A with theanine synthetase increased theanine production 672% in an in vitro system. This study provides the structural basis for the substrate selectivity and catalytic activity of CsAlaDC and AtSerDC and provides a route to more efficient biosynthesis of theanine.

Structure and evolution of alanine/serine decarboxylases and the engineering of theanine production

Ethylamine (EA), the precursor of theanine biosynthesis, is synthesized from alanine decarboxylation by alanine decarboxylase (AlaDC) in tea plants. AlaDC evolves from serine decarboxylase (SerDC) through neofunctionalization and has lower catalytic activity. However, lacking structure information hinders the understanding of the evolution of substrate specificity and catalytic activity. In this study, we solved the X-ray crystal structures of AlaDC from Camellia sinensis (CsAlaDC) and SerDC from Arabidopsis thaliana (AtSerDC). Tyr341 of AtSerDC or the corresponding Tyr336 of CsAlaDC is essential for their enzymatic activity. Tyr111 of AtSerDC and the corresponding Phe106 of CsAlaDC determine their substrate specificity. Both CsAlaDC and AtSerDC have a distinctive zinc finger and have not been identified in any other Group II PLP-dependent amino acid decarboxylases. Based on the structural comparisons, we conducted a mutation screen of CsAlaDC. The results indicated that the mutation of L110F or P114A in the CsAlaDC dimerization interface significantly improved the catalytic activity by 110% and 59%, respectively. Combining a double mutant of CsAlaDCL110F/P114A with theanine synthetase increased theanine production 672% in an in vitro system. This study provides the structural basis for the substrate selectivity and catalytic activity of CsAlaDC and AtSerDC and provides a route to more efficient biosynthesis of theanine.

Functional and Mechanistic Dissection of Protein Glutaminase PG3 and Its Rational Engineering for Enhanced Modification of Myofibrillar Proteins.

Protein glutaminases (PG; EC = 3.5.1.44) are enzymes known for enhancing protein functionality. In this study, we cloned and expressed the gene chryb3 encoding protein glutaminase PG3, exhibiting 39.4 U/mg specific activity. Mature-PG3 featured a substrate channel surrounded by aromatic and hydrophobic amino acids at positions 38-45 and 78-84, with Val81 playing a pivotal role in substrate affinity. The dynamic opening and closing motions between Gly65, Thr66, and Cys164 at the catalytic cleft greatly influence substrate binding and product release. Redesigning catalytic pocket and cocatalytic region produced combinatorial mutant MT6 showing a 2.69-fold increase in specific activity and a 2.99-fold increase at t65°C1/2. Furthermore, MT6 boosted fish myofibrillar protein (MP) solubility without NaCl. Key residues such as Thr3, Asn54, Val81, Tyr82, Asn107, and Ser108 were vital for PG3-myosin interaction, particularly Asn54 and Asn107. This study sheds light on the catalytic mechanism of PG3 and guided its rational engineering and utilization in low-salt fish MP product production.

Research on composite material riveting simulation method for engineering applications

PurposeIn order to improve the efficiency and reliability of simulation analysis for composite riveting structures in engineering products, a comparative study was conducted on different forms of riveting simulation methods.Design/methodology/approachFive different rivent simulation models were established using the finite element method, including rigid element CE, flexible element Rbe3 and beam element, and their results were future compared and analyzed.FindingsUnder the given technical parameters, the simulation method of Rbe3 (with holes) + beam can meet the analysis requirements of complex engineering products in terms of the rationality of rivet load distribution, calculation error and relatively efficient modeling.Originality/valueThis study proposes a simulation method for the riveting structure of carbon fiber composite materials for engineering applications. This method can satisfy the simulation analysis requirements of transportation vehicles in terms of modeling time, computational efficiency and accuracy. The research can provide technical support for the riveting process and mechanical analysis between carbon fiber composite components in transportation products.

Working conditions and health status in workers in boiler and welding production in power engineering

Introduction. Preserving the health of qualified workers of older age groups is especially important under conditions of exposure to occupational hazards. The purpose of the study was to assess the influence of occupational hazards on the development of occupational and somatic diseases among workers of various age groups in the main occupations of mechanical engineering. Materials and methods. The study tested the results of hygienic research at workplaces of an enterprise in the power engineering industry in the manufacture of welded metal structures. We assessed the health status in workers based on the results of an in-depth medical examination and ultrasound examination of the vessels of the upper extremities with assessment of blood flow indices. Using a survey method, data were obtained on assessing the influence of production factors on the health status in workers. Results. The working conditions in the main occupational workers groups were assessed as harmful grades 1–3, the priority occupational hazards were: increased noise, and at the workplaces of electric gas workers there were also fibrogenic aerosols, chemical substances, and heavy physical work. Electric and gas welders and boilermakers work in the most unfavourable conditions, about 30% of whom continue to work after reaching retirement age. We have established a significant gain in the incidence of arterial hypertension and sensorineural hearing loss among workers over 40 years of age and an increase in the prevalence of all chronic diseases in the age group over 60 years. Limitations. The study is limited by the number of workers examined and the lack of ability to assess the health status of the studied contingent of workers over time. Conclusion. In conditions of exposure to elevated noise and other occupational hazards, there is an enhancement in the prevalence of work-related and somatic diseases in workers over 40 years of age. With advancing age, the rise in the vascular resistance index is observed, however, the first signs of peripheral blood flow disturbance are often recorded at a young age. In this regard, it is necessary to introduce methods of early diagnosis and prevention of occupational and work-related pathology.

Assessment of Chondrogenic Potential of Human Dermal Fibroblasts with Various Protein Modifications

BACKGROUND: Hyaline cartilage is an avascular tissue that covers surface of large joints. This tissue, with a small number of cells and a high content of extracellular matrix proteins, has limited regenerative capacity. Recovery the articular cartilage remains a relevant and not yet fully resolved issue today. A promising approach is the use of biomedical products containing modified cells. AIM: To investigate the effects of different culture media on the chondrogenic modification of cells and to compare the results. METHODS: Human dermal fibroblasts and rabbit mesenchymal stem cells were modified using chondrogenic differentiation medium StemPro or recombinant TGF-β3 protein. Changes in the expression of genes responsible for chondrogenesis (Acan, Tgfβ3, Col2α1, Comp) were measured using the Real-Time PCR method -2ΔΔCt. RESULTS: It was shown that human dermal fibroblasts are capable of chondrogenic modification using protein media. This cell type is easily accessible for harvesting, does not require special conditions for cultivation, is easily scalable, and can be used for allogeneic transplantation. CONCLUSION: The obtained data can be used in the design of tissue engineering products for the regeneration of hyaline cartilage based on allogeneic dermal fibroblasts.

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

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