Mechanical Machinery Research Articles

Reduced-Order Modeling for Dynamic System Identification with Lumped and Distributed Parameters via Receptance Coupling Using Frequency-Based Substructuring (FBS)

Paper presents an effective technique for developing reduced-order models to predict the dynamic responses of systems using the receptance coupling and frequency-based substructuring (RCFBS) method. The proposed approach is particularly suited for reconfigurable dynamic systems across various applications, like cars, robots, mechanical machineries, and aerospace structures. The methodology focuses on determining the overall system receptance matrix by coupling the receptance matrices (FRFs) of individual subsystems in a disassembled configuration. Two case studies, one with distributed parameters and the other with lumped parameters, are used to illustrate the application of this approach. The first case involves coupling three substructures with flexible components under fixed–fixed boundary conditions, while the second case examines the coupling of subsystems characterized by multiple masses, springs, and dampers, with various internal and connection degrees of freedom. The accuracy of the proposed method is validated against a numerical finite element analysis (FEA), direct methods, and a modal analysis. The results demonstrate the reliability of RCFBS in predicting dynamic responses for reconfigurable systems, offering an efficient framework for reduced-order modeling by focusing on critical points of interest without the need to account for detailed modeling with numerous degrees of freedom.

Analysis and evaluation of energy efficiency of a shrinkwrap-packer

Since some years, European companies are interested in the issue of energy saving. In such context, a classification of industrial machines from the energetic point of view is becoming more and more important; currently, in the industrial context, no similar classifications exist. The aim of this work is to formulate a standard method to evaluate the energy performance of an industrial machine, such as a shrinkwrap-packer. To this purpose, we studied a shrinkwrap-packer produced by OCME S.r.l, a mechanical machinery company located in Parma (Italy). Specifically, the shrinkwrap-packer was analyzed in terms of energy dissipations and other aspects related to the energy source utilized to power the oven. As a result, we propose a general procedure that allows to compare different solutions from different perspectives related to energy efficiency. More precisely, we include three key performance indicators (KPIs) of energy efficiency, to build a comprehensive evaluation model. The first KPI concerns the energy efficiency class of the oven, the second KPI takes into account the impact of the oven on the work environment and the third one is an index of degradation of the energy resource utilized. A Global Index of Energy Efficiency (GI) is finally computed as the area of a triangle represented on a radar diagram on three axes, one for each KPI.

Peningkatan Kualitas Emping Melinjo melalui Proses Pengepresan dan Penurunan Kadar Purin di UKM Emping Jago

<em><em><strong>Quality Improvement of Emping Melinjo through Pressing Process and Reduction of Purin Level at SME Emping Jago.</strong> </em>Emping melinjo is one of the popular foods among Indonesians. Kartasura is one of the districts in Sukoharjo that has potential in the production of emping melinjo. This study aimed to improve the quality of emping melinjo by using a mechanical pressing machine and reducing the purin level. The method used was a literature review based on scientific journals, books, and others. The results were to substitute the pressing process using mechanical machinery and by soaking treatment to reduce the purin levels. The improvement on pressing process were performed as an innovation so the process will not depend on human workers. Then, the soaking in a 4% acetic acid solution (vinegar) varied for 0; 10; 20; and 40 minutes.The hypoxanthine and adenine levels (in micrograms per gram), according to the soaking duration, showed 46,43; 41,50; 41,05; 36,71; and 124,74; 110,90; 109,83; 108,82 respectively. <em>The 40 minutes soaking process could decrease the purin level by 20%.</em></em>

Production of Recycling Prototype of Machining Teflon Waste by Compression Molding and Sintering and Investigation of Mechanical Properties

In this study, for the first time within the Arnes Mechanical Machinery Design Center, the recycling of Teflon (PTFE-Polytetrafluorethylene) wastes generated in the production of sealing elements by machining process was carried out, and know-how was obtained for the use of this recycling prototype as a secondary raw material. Within the scope of the study, the recycling prototype, which was separated as waste after the machining process, was characterized by DSC analysis and ground to 250-micron sizes. The resulting Teflon prototype was pressed by pressure molding and sintering processes. 370-390°C temperature and 2-4 hours time parameters were selected for sintering. To determine the mechanical properties of the secondary raw material prepared as a recycling prototype, a tensile test mold was designed, and tensile test samples were produced. As a result of the study, it was seen that the recycling Teflon prototype was successfully produced. It was determined that the mechanical properties of the produced prototype improved with increasing sintering temperature and time. Environmental sustainability will be ensured by reusing the second-quality raw materials from the study in production.

Toward a continuum description of lubrication in highly pressurized nanometer-wide constrictions: The importance of accurate slip laws.

The Reynolds lubrication equation (RLE) is widely used to design sliding contacts in mechanical machinery. While providing an excellent description of hydrodynamic lubrication, friction in boundary lubrication regions is usually considered by empirical laws, because continuum theories are expected to fail for lubricant film heights h0 ≪ 10 nm, especially in highly loaded tribosystems with normal pressures pn ≫ 0.1 GPa. Here, the performance of RLEs is validated by molecular dynamics simulations of pressurized (with pn = 0.2 to 1 GPa) hexadecane in a gold converging-diverging channel with minimum gap heights h0 = 1.4 to 9.7 nm. For pn ≤ 0.4 GPa and h0 ≥ 5 nm, agreement with the RLE requires accurate constitutive laws for pressure-dependent density and viscosity. An additional nonlinear wall slip law relating wall slip velocities to local shear stresses extends the RLE's validity to even the most severe loading condition pn = 1 GPa and h0 = 1.4 nm. Our results demonstrate an innovative route for continuum modeling of highly loaded tribological contacts under boundary lubrication.

In Vitro Reconstitution of the Actin Cytoskeleton Inside Giant Unilamellar Vesicles.

The actin cytoskeleton, the principal mechanical machinery in the cell, mediates numerous essential physical cellular activities, including cell deformation, division, migration, and adhesion. However, studying the dynamics and structure of the actin network in vivo is complicated by the biochemical and genetic regulation within live cells. To build a minimal model devoid of intracellular biochemical regulation, actin is encapsulated inside giant unilamellar vesicles (GUVs, also called liposomes). The biomimetic liposomes are cell-sized and facilitate a quantitative insight into the mechanical and dynamical properties of the cytoskeleton network, opening a viable route for bottom-up synthetic biology. To generate liposomes for encapsulation, the inverted emulsion method (also referred to as the emulsion transfer method) is utilized, which is one of the most successful techniques for encapsulating complex solutions into liposomes to prepare various cell-mimicking systems. With this method, a mixture of proteins of interest is added to the inner buffer, which is later emulsified in a phospholipid-containing mineral oil solution to form monolayer lipid droplets. The desired liposomes are generated from monolayer lipid droplets crossing a lipid/oil-water interface. This method enables the encapsulation of concentrated actin polymers into the liposomes with desired lipid components, paving the way for in vitro reconstitution of a biomimicking cytoskeleton network.

Forming Micro-and Nano-Plastics from Agricultural Plastic Films for Employment in Fundamental Research Studies.

Microplastics (MPs) and nanoplastics (NPs) dispersed in agricultural ecosystems can pose a severe threat to biota in soil and nearby waterways. In addition, chemicals such as pesticides adsorbed by NPs can harm soil organisms and potentially enter the food chain. In this context, agriculturally utilized plastics such as plastic mulch films contribute significantly to plastic pollution in agricultural ecosystems. However, most fundamental studies of fate and ecotoxicity employ idealized and poorly representative MP materials, such as polystyrene microspheres. Therefore, as described herein, we developed a lab-scale multi-step procedure to mechanically form representative MPs and NPs for such studies. The plastic material was prepared from commercially available plastic mulch films of polybutyrate adipate-co-terephthalate (PBAT) that were embrittled through either cryogenic treatment (CRYO) or environmental weathering (W), and from untreated PBAT pellets. The plastic materials were then treated by mechanical milling to form MPs with a size of 46-840 µm, mimicking the abrasion of plastic fragments by wind and mechanical machinery. The MPs were then sieved into several size fractions to enable further analysis. Finally, the 106 µm sieve fraction was subjected to wet grinding to generate NPs of 20-900 nm, a process that mimics the slow size reduction process for terrestrial MPs. The dimensions and the shape for MPs were determined through image analysis of stereomicrographs, and dynamic light scattering (DLS) was employed to assess particle size for NPs. MPs and NPs formed through this process possessed irregular shapes, which is in line with the geometric properties of MPs recovered from agricultural fields. Overall, this size reduction method proved efficient for forming MPs and NPs composed of biodegradable plastics such as polybutylene adipate-co-terephthalate (PBAT), representing mulch materials used for agricultural specialty crop production.

Risk as a driver for AI framework development on manufacturing

Incorporating ethics and values within the life cycle of an AI asset means to secure, under these perspectives, its development, deployment, use and decommission. These processes must be done safely, following current legislation, and incorporating the social needs towards having greater well-being over the agents and environment involved. Standards, frameworks and ethical imperatives—which are also considered a backbone structure for legal considerations—drive the development process of new AI assets for industry. However, given the lack of concrete standards and robust AI legislation, the gap between ethical principles and actionable approaches is still considerable. Different organisations have developed various methods based on multiple ethical principles to facilitate practitioners developing AI components worldwide. Nevertheless, these approaches can be driven by a self-claimed ethical shell or without a clear understanding of the impacts and risks involved in using their AI assets. The manufacturing sector has produced standards since 1990’s to guarantee, among others, the correct use of mechanical machinery, workers security, and environmental impact. However, a revision is needed to blend these with the needs associated with AI’s use. We propose using a vertical-domain framework for the manufacturing sector that will consider ethical perspectives, values, requirements, and well-known approaches related to risk management in the sector.

KINEMATIC ANALYSIS OF THE STRUCTURES OF A SINGLE BUCKET LOADER WITH A TRANSFORMING WORKING EQUIPMENT

When justifying the design of newly created equipments of mechanization (machinery and equipment), after preliminary design, it is necessary to perform calculations for strength, reliability and durability. With the determination of the kinematic parameters of the working equipment, we find the speed of movement of certain links of the mechanisms, the results of which will be used to solve dynamic tasks.

A responsible AI framework: pipeline contextualisation

Incorporating ethics and values within the life cycle of an AI asset means securing its development, deployment, use, and decommission under these perspectives. These approaches depend on the market domain where AI is operational – considering the interaction and the impact on humans if any process does not perform as expected – and the legal compliance, both required to ensure adequate fulfilment of ethics and values. Specifically, in the manufacturing sector, standards were developed since the 1990’s to guarantee, among others, the correct use of mechanical machinery, systems robustness, low product variability, workers safety, system security, and adequate implementation of system constraints. However, it is challenging to blend the existing practices with the needs associated with deployments of AI in a trustworthy manner. This document provides an extended framework for AI Management within the Manufacturing sector. The framework is based on different perspectives related to responsible AI that handle trustworthy issues as risk. The approach is based on the idea that ethical considerations can and should be handled as hazards. If these requirements or constraints are not adequately fulfilled and managed, it is expected severe negative impact on different sustainable pillars. We are proposing a well-structured approach based on risk management that would allow implementing ethical concerns in any life cycle stages of AI components in the manufacturing sector. The framework follows a pipeline structure, with the possibility of being extended and connected with other industrial Risk Management Processes, facilitating its implementation in the manufacturing domain. Furthermore, given the dynamic condition of the regulatory state of AI, the framework allows extension and considerations that could be developed in the future.

Chemistry and particle size distribution of respirable coal dust in underground mines in Central Eastern Europe

Despite international efforts to limit worker exposure to coal dust, it continues to impact the health of thousands of miners across Europe. Airborne coal dust has been studied to improve risk models and its control to protect workers. Particle size distribution analyses shows that using spraying systems to suppress airborne dusts can reduce particulate matter concentrations and that coals with higher ash yields produce finer dust. There are marked chemical differences between parent coals and relatively coarse deposited dusts (up to 500 µm, DD500). Enrichments in Ca, K, Ba, Se, Pb, Cr, Mo, Ni and especially As, Sn, Cu, Zn and Sb in the finest respirable dust fractions could originate from: (i) mechanical machinery wear; (ii) variations in coal mineralogy; (iii) coal fly ash used in shotcrete, and carbonates used to reduce the risk of explosions. Unusual enrichments in Ca in mine dusts are attributed to the use of such concrete, and elevated K to raised levels of phyllosilicate mineral matter. Sulphur concentrations are higher in the parent coal than in the DD500, probably due to relatively lower levels of organic matter. Mass concentrations of all elements observed in this study remained below occupational exposure limits.

A nanographene disk rotating a single molecule gear on a Cu(111) surface

On Cu(111) surface and in interaction with a single hexa-tert-butylphenylbenzene molecule-gear, the rotation of a graphene nanodisk was studied using the large-scale atomic/molecular massively parallel simulator molecular dynamics simulator. To ensure a transmission of rotation to the molecule-gear, the graphene nanodisk is functionalized on its circumference by tert-butylphenyl chemical groups. The rotational motion can be categorized underdriving, driving and overdriving regimes calculating the locking coefficient of this mechanical machinery as a function of external torque applied to the nanodisk. The rotational friction with the surface of both the phononic and electronic contributions is investigated. For small size graphene nanodisks, the phononic friction is the main contribution. Electronic friction dominates for the larger disks putting constrains on the experimental way of achieving the transfer of rotation from a graphene nanodisk to a single molecule-gear.

Sparse transfer learning for identifying rotor and gear defects in the mechanical machinery

It is incredibly difficult to build a data-driven machine learning model for the automatic detection of defects in rotating machinery. The existing techniques, based on machine learning models, work satisfactory for one machinery but unsatisfactorily for others. The problem of identifying defects becomes sever when the enough training data is not available. Here, a sparse deep learning model is put forward that can efficiently learn from the limited training data. The existing cost function of CNN has been improved by adding sparsity cost for the purpose of improving the performance of deep learning. To assimilate the sparsity, unnecessary activation of neurons is averted in the feature extraction layer of CNN. A trigonometric sparsity cross entropy (TSCE) function is built to obtain the sparsity cost. The updated CNN is trained with enough samples from the source domain. Thereafter, fine-tuning of the model is carried out from small data samples of the target domain for detecting defects. The testing of proposed deep learning model is carried out on two types of data set, one is gear and another is rotor. The concluding results obtained from the proposed work has been compared with current state-of-the-artwork. The comparison analysis shows the usefulness of the proposed methodology over the existing methods.

Investigation of fracture behaviour of asymmetric spur gear

As a high power transmission capacity and long durability constitute an essential requirement for mechanical machinery, the mechanical transmission gears need to be modified to improve the performance. The increasing drive side pressure angle is one of the methods for enhancing load-carrying capacity of the spur gear. The fracture characteristics of asymmetric gears need to be investigated to estimate the fatigue life. The location and magnitude of stress intensity factors mainly depend on gear tooth geometry, gear parameters, crack tip location, and applied force. Most of the literature study of fracture analysis carried out for the symmetric gears and the majority of them are two-dimensional analysis. In this study, a parametric analysis carried out for asymmetric spur gears to examine the fracture behaviour under mixed-mode fracture condition and explore the significance of each gear parameters. The maximum bending stress location for each gear pair is determined and the crack is introduced at that region. The stress intensity factor (SIF) for each mode is estimated and the effective stress intensity factor at each node along the face width is determined. In addition, the effect of opening mode, sliding mode and tearing mode on effective stress intensity factor for fillet crack is examined. This analysis inferred that the effect of opening mode fracture is predominant in the effective stress intensity factor irrespective of gear parameters.

Surface-Phonon-Induced Rotational Dissipation for Nanoscale Solid-State Gears

Compared to nanoscale friction of translational motion, the mechanisms of rotational friction have received less attention. Such motion becomes an important issue for the miniaturization of mechanical machinery that often involves rotating gears. In this study, molecular-dynamics simulations are performed to explore rotational friction for solid-state gears rotating on top of different substrates. In each case, viscous damping of the rotational motion is observed and found to be induced by the pure van der Waals interaction between the gear and the substrate. The influence of different gear sizes and various substrate materials is investigated. Furthermore, the rigidities of the gear and the substrate are found to give rise to different dissipation channels. Finally, it is shown that the dominant contribution to the dissipation is related to the excitation of low-frequency surface phonons in the substrate.

Design and Performance Investigation of 3-Slot/2-Pole High Speed Permanent Magnet Machine

High-speed rotating mechanical machinery is a developed, mature and reliable technology for many engineering applications. In high-speed permanent magnet machines, the rotor's permanent magnet PM is not strong enough to withstand the centrifugal force resulting from excessive rotational speed; thus, the PM material must be protected by a non-magnetic alloy sleeve. This paper presents a novel high-speed PM machine with solid rotor PM covered by a titanium retaining sleeve. The rotor stress condition is simplified as a plane stress problem according to the strength measurement of solid PM rotors in the high-speed PM motors. The analytical formulas for rotor stress are presented based on the polar coordinate displacement method. The proposed model is compared with a conventional model having auxiliary slots in stator teeth. Using a finite element analysis environment, the performance analysis shows that the proposed design has reduced magnet eddy current loss, cogging torque, and iron losses. The initial design is also optimized using a deterministic optimization algorithm that increases output torque by 26% compared to the initial design.

Evaluation of machine tool substitute under data-driven quality management system: a hybrid decision-making approach

PurposeToday, industrial revolutions demands advanced technologies, means, mediums, tactics and so forth for optimizing their operating behavior and opportunities. It is probed that the effectual results can be seized into system by not only developing advance means and technologies, but also capably adapting these developed technologies, their user interface and their utilization at optimum levels. Today, industrial resources need perfect synchronization and optimization for getting elevated results. Accordingly, present study is furnished with the purpose to expose quality-driven insights to march toward excellence by optimizing existing resources by the industrial organizations. The present study evaluates quality attributes of mechanical machineries for seizing performance opportunities and maintaining competitiveness via synchronizing and reconfiguring firm's resources under quality management system.Design/methodology/approachIn the present study, Kano’s integrated approach is implemented for supporting decision rational concerning industrial assets. The integrative Kano–analytic hierarchy process (AHP) approach is used to reflect the relative importance of quality attributes. Kano and AHP tactics are integrated to define global relative weight and their computational medium is adapted along with ratio analysis, reference point theory and TOPSIS technique for understanding robust decision. The study described an interesting idea for underpinning quality attributes for benchmarking system substitutes. A machine tool selection case is discussed to disclose the significant aspect of decision-making and its virtual qualities.FindingsThe decision executives can realize massive benefits by streaming quality data, advanced information, technological advancements, optimum analysis and by identifying quality measures and disruptions for gaining performance deeds. The study determined quality measures for benchmarking machine tool substitute for industrial applications. Momentous machine alternatives are evaluated by means of technical structure, dominance theory and comparative analysis for supporting decision-making of industrial assets based on optimization and synchronization.Research limitations/implicationsThe study linked financial, managerial and production resources under sole platform to present a technical structure that may assist in improving the performance of the manufacturing firms. The study provides a decision support mechanism to assist in reviewing the momentous resources to imitate a higher level of productive strength toward the manufacturing firms. The study endeavors its importance toward optimizing resources, which is an evident requirement in industries as the same not only saves money, escalates production, improves profit margins and so forth, but also gratifies the consumption of scarce natural resources.Originality/valueThe study stressed that advance information can be sought from system characteristics in the form of quality measures and attributes, which can be molded for gaining elevated outcomes from existing system characteristics. The same demands decision supports tools and frameworks to utilize data-driven information for benchmarking operations and supply chain activities. The study portrayed an approach for ease of utilizing data-driven information by the decision-makers for demonstrating superior outcomes. The study originally conceptualized multi-attributes appraisement framework associated with subjective cum objective quality measures to evaluate the most significant machine tool choice amongst preferred alternatives.

Gas plasma-spurred wound healing is accompanied by regulation of focal adhesion, matrix remodeling, and tissue oxygenation

In response to injury, efficient migration of skin cells to rapidly close the wound and restore barrier function requires a range of coordinated processes in cell spreading and migration. Gas plasma technology produces therapeutic reactive species that promote skin regeneration by driving proliferation and angiogenesis. However, the underlying molecular mechanisms regulating gas plasma-aided cell adhesion and matrix remodeling essential for wound closure remain elusive. Here, we combined in vitro analyses in primary dermal fibroblasts isolated from murine skin with in vivo studies in a murine wound model to demonstrate that gas plasma treatment changed phosphorylation of signaling molecules such as focal adhesion kinase and paxillin α in adhesion-associated complexes. In addition to cell spreading and migration, gas plasma exposure affected cell surface adhesion receptors (e.g., integrinα5β1, syndecan 4), structural proteins (e.g., vinculin, talin, actin), and transcription of genes associated with differentiation markers of fibroblasts-to-myofibroblasts and epithelial-to-mesenchymal transition, cellular protrusions, fibronectin fibrillogenesis, matrix metabolism, and matrix metalloproteinase activity. Finally, we documented that gas plasma exposure increased tissue oxygenation and skin perfusion during ROS-driven wound healing. Altogether, these results provide critical insights into the molecular machinery of gas plasma-assisted wound healing mechanisms.

ANALISIS KEKUATAN TARIK LOGAM PADUAN Al-Cu-Mg SEBAGAI DUDUKAN SHOCK ABSORBER SEPEDA MOTOR

Aluminum is a non-ferrous metal that has good thermal conductivity and is widely used in various mechanical machinery systems. Efforts to obtain additional mechanical strength from aluminum can be combined with Cu, Mg, Si, Mn, Ni and so on. This research was made to prepare a Motorcycle Shock Absorber that is useful as a pedestal and handle shock breakers against the swing arm, with aluminum alloy material (Al), copper (Cu), and magnesium (Mg). The purpose of this research is to know the tensile strength and know the value of the strain. The method of this research process is aluminum alloy with a variation of Specimen 1 ratio is 3% copper and 7% magnesium, for Specimen 2 replacement is 5% copper and 5% magnesium, and the variations that support Specimen 3 are 7% copper and 3% magnesium. From the results of this study, the tensile strength and strain values ​​obtained in specimen 1 were 125.5 MPa and 3.56%. For specimen 2 the tensile strength and strain values ​​were 150 Mpa and 3.42%. While the specimens of 100% tensile strength and strain are 137 Mpa and 7.48%. The best results from copper and magnesium alloys are Al alloys of 90%, Cu 5% and Mg 5%, with a tensile strength value of 150 MPa and a strain value of 3.42%.

A terminologia do maquinário para produção de celulose e a lexicografia pedagógica: relações didático-pedagógicas

Os termos de uma determinada área de conhecimento técnico ou científico fazem parte dos princípios basilares para se compreender o funcionamento de uma língua, especialmente no que se refere aos seus possíveis usos. Dessa maneira, identificar equivalentes, ou mesmo propor alternativas de denominação, princípios fundamentais da Terminologia, motivaram o desenvolvimento de um projeto voltado para o entendimento de termos utilizados no domínio da produção de celulose, mais especificamente relacionados ao maquinário de mecanização do viveiro de mudas em grandes empresas de plantio de eucalipto. A proposta deste trabalho, portanto, é relacionar conceitos da Lexicografia Pedagógica ao domínio de Produção de Celulose: maquinário de mecanização do viveiro de mudas, visando propor uma reflexão acerca da estruturação de aulas e atividades em língua inglesa, utilizando-se de um dicionário bilíngue inglês-português, para que se possa fornecer conhecimento linguístico necessário ao entendimento do manual de montagem e manutenção dos equipamentos em questão.