Modern Machines Research Articles

Mechanical Properties of Spunlace Non-Wovens with a Porous Structure

The paper describes the influence of the drum system construction of two modern carding machines on the porous structure of spunlace non-wovens composed of polyester and viscose. The non-woven fabric structure, including the number and size of the pores, determines the tensile strength of the composites obtained. The spunlace non-wovens were subjected to tensile strength tests in the machine, and cross-directions and microscopic observations of their structure were made. The results of the experiments were used to determine the relationship between the strength of the material and the porosity of its structure. This knowledge was used to prepare recommendations for the manufacturer of wet wipes in order to enable the selection of a carding machine for the mass production of final products with strength properties that meet market requirements and satisfy the end customer.

Effect of pre-squeezing force in a single-sizing-roll triple-roll-type sizing machine on size pick-up and quality indexes of sized yarns

Cotton warp sizing is the precondition for guaranteeing smooth weaving. Pre-squeezing is one of the processes for sizing in modern multi-squeezing roll sizing machines, which plays a positive role in the rational distribution of sizing material in sized yarn. However, the effect of pre-squeezing force on the properties of sized yarn is not clear. In this study, the mixed size liquor of starch acetate and PVA 088-05 was modified to reduce its viscosity at room temperature; subsequently, the warp yarns were sized by a single-sizing-roll triple-roll-type sizing machine. The effect of pre-squeezing force on the size pick-up and quality indexes of sized yarns was investigated. The results revealed that there was a positive correlation between pre-squeezing force and the size pick-up of sized yarn. The breaking force, abrasion resistance, abrasion residual breaking force, and hairiness number of sized yarns first increased and then decreased as the pre-squeezing force was increased. The analysis of variance indicated that pre-squeezing force significantly affected size pick-up percentage, breaking force and elongation, abrasion resistance, and hairiness of sized yarns. This study clarifies the relationship between pre-squeezing force and sized yarn quality indexes, which can offer a beneficial reference for the selection of pre-squeezing force in sizing production.

Actuators for Large Wind Energy Systems—A Tutorial-Focused Survey

Undoubtedly, wind turbines are currently one of the most significant contributors to clean energy. Therefore, it is crucial to enhance the capability of wind turbines, which in turn leads to an increase in their dimensions. Nevertheless, only advanced control systems can guarantee the optimal and secure operation of these huge machines. On the other hand, the precise control of these modern wind turbines is only achievable through the use of highly specialised actuators. Despite their importance, actuators have historically been overlooked and seen as secondary components in control systems. However, in modern machines, actuators are required to manipulate multiple tonnes or manage thousands of volts and amperes within short times. Consequently, greater emphasis must be placed on their handling and operation. This study aims to review actuators for modern large wind energy converters from a control engineering perspective, using a tutorial approach.

The Si-doped BCC-based high-entropy alloy to overcome soft magnetic–mechanical properties trade-off via coherent B2 nanoprecipitates

The trade-off between magnetic property and mechanical property usually occurs in traditional soft magnetic materials (SMMs) because the strengthening strategy (e.g. precipitation hardening) can worsen soft magnetic properties through the hindrance of magnetic domain wall motion. This dilemma is overcome in current work by developing the FeCoNiAlSi0.01 (Fe24.94Co24.94Ni24.94Al24.94Si0.24 in at.%) high-entropy alloy (HEA) (termed as Si0.24 HEA) with excellent soft magnetic performance and attractive mechanical property through coherent B2 nanoprecipitates (6 nm) distributed in body-centered-cubic (BCC) matrix. The atom probe tomography (APT) result shows that the B2 nanoprecipitates have similar composition to the BCC matrix. The Si0.24 HEA shows small width of domain branching and low anisotropy constant leading to the optimum alternating current (AC) soft magnetic properties. The respective total loss (AC Ps), the coercivity (AC Hc), and the eddy current loss (Pe) at 950 Hz of the Si0.24 HEA are 21.20 W/kg, 230 A/m, and 16.25 W/kg, which is reduced by 45 %, 44 %, and 48 % compared with the FeCoNiAl (Si-free HEA). The Si0.24 HEA shows good mechanical property with the yield strength of 987 MPa and engineering strain of 30 %, which is 12 % and 1.3 times higher than that of the Si-free HEA. Moreover, the current studied HEAs exhibit high saturation magnetization (Ms = 108–115 Am2/kg) and Curie temperature (TC = 1053–1097 K, larger than TC of Fe (1043 K)), which indicates their perspective high-temperature applications as novel SMMs for the need of modern power electronics and electrical machines.

Hygienic assessment of the protective properties of personal hand protection equipment during vibration testing

Introduction. In industrial environments, at the workplaces of hand tool operators, it is not always possible to completely eliminate increased levels of vibration exposure. The power and speed characteristics of modern hand-held machines are constantly increasing. The impact of local vibration on a person has a negative effect on his body. When working with hand tools, personal protective equipment is used. The purpose of personal hand protection against vibration is to reduce the vibration impact on a person. Materials and methods. Bench tests were carried out on hand protection products consisting of damping materials of various shapes and locations in the product. The vibration sensor was installed and fastened in places where the operator’s hands came into contact with vibration and on the forearm. The effectiveness of protection was determined by the difference in measurement levels. Results. During the tests, vibration levels were recorded on the handle of the vibration stand, the palmar surface, the fingers, and the operator’s forearm. In the low-frequency region of the spectrum, vibration attenuation is minimal, and as the frequency range increases, the attenuation increases. Across all areas of the spectrum, performance levels for mittens are higher than for gloves. In places where the fingers come into contact with vibration, the efficiency is less than when in contact with the hand, and in the low-frequency region of the spectrum a negative efficiency of up to 0.8 dB is noted. Vibration measurements on the operator’s forearm showed vibration levels in the forearm to be lower than in the hand. Limitations. The study was conducted over a period of one year, in laboratory conditions, and was limited to two thousand measurements. Conclusion. Hygienic assessment of the effectiveness of the protective properties of personal protective equipment for hands was carried out in accordance with developed laboratory test methods when installing and securing a vibration sensor on the handle, hand, and forearm of the operator. Determining the effectiveness of the entire product model should be considered when designing and manufacturing new hand protection against vibration.

Design of hydraulic motors with rotary shaft movement for driving working equipment in modern machines

The object of research is the processes in hydraulic motors based on power cylinders, designed to drive the shaft of the working equipment in modern machines into rotational motion. When using standard motors, a problem arises relating to the need to introduce additional devices into the structure of the mechanisms of modern machines. Such devices are aimed at matching the rotation frequency of the motor shaft with the rotation shaft of the working equipment of these machines. Such a device is a reducer, the use of which leads to the appearance of a number of disadvantages. Their elimination is achieved by using the results of this study. The reported results differ from standard motors that are mass-produced, in that, based on research, motors with a rotation frequency of its shaft in the range from zero to two hundred and more revolutions per minute are proposed, which is not realized by known motors. This testifies to the construction of motors based on power cylinders, which make it possible to realize this range of rotation frequencies of its shaft. The special and distinctive features of the results are based on the application of the principle of disintegration of motor elements into two functional components. One of them includes power cylinders with a crankshaft, and the second one includes the distribution system of the working fluid. The motor implementation went through the stages of designing computer and physical models and devising schematic solutions. Calculation dependences were obtained to determine the main design parameters, according to which the motor was manufactured in the form of a full-scale sample. The scope and conditions of practical use refer to machines with working equipment capable of functioning under a mode with a low rotation frequency and a significant torque on the motor shaft

Highland bamboo value chains development to enhance local livelihoods in Southern Ethiopia

Highland bamboo has been traditionally used in building construction, wall partitioning, ceiling, doors, windows, and roofs and has contributed in people’s livelihoods. This paper focuses on pinpointing bamboo value chain, its opportunities, and challenges. Site selection and observation, review of existing knowledge, key informant interview and market assessment in the value chain, stakeholders’ consultation workshop, processors workspace visit, and group discussion were performed. We found that highland bamboo is a raw material, semi-processed and processed product and sold at different locations passing through different routes based on the request and demand of the customers in the value chain. We identified different bamboo landraces in the studied areas. However, there are knowledge gaps by processors on the use of the different races for different purposes. Traders buy bamboo culms based on their sizes by giving different grades. The price of the product varied from product to product depending on the quality of bamboo raw material/culm used and the time (man-days) required to make the finished product. Local processors’ capacity to produce well-finished products is affected due to lack of important machineries and tools. Therefore, introducing and promoting modern processing tools and machines through credit support systems are crucial to make processors more competitive in the value chain. Moreover, the study identified major challenges faced by bamboo growers, culm traders, and processors that have effects on bamboo value chain development. Therefore, it is important to work towards alleviating/minimizing the major challenges in the bamboo value chain considering all actors to strive towards improving the value chain.

A global plasma and surface model of hydrogen/methane inductively coupled discharge to analyze hydrocarbon plasma–surface interactions in extreme-ultraviolet lithography machines

Hydrocarbon contamination is associated with light transmission losses in modern lithography machines, which contain extreme-ultraviolet-induced plasma. A volume-averaged global and deposition/etch surface model of a reference hydrogen/methane inductive discharge is developed to investigate the plasma–surface interactions. The simulation results are validated against a wide variety of experiments and verified with respect to multiple sets of computational data. The deposition rate is calculated for a variation in methane impurity (10–10 000 ppm), power, pressure, and net mass flow. The simulations conclude that the hydrocarbon plasma deposition can be minimized by reducing methane impurity and excluding solid organic structures.

The State of Health of Electrical Connectors

For modern machines, factories and electric and autonomous vehicles, the importance of vreliable electrical connectors cannot be overstated. With an increasing number of connectors being used in machines, factories and vehicles, ensuring their reliability is crucial for comfort and safety alike. One of the key indicators of reliability is the lifetime of connectors. To evaluate the lifetime of electrical connectors, a testing method and a model for calculating their lifetime based on the test data were developed. The results from these tests were compared to failure analysis data from long-term field operations. The findings indicate that the laboratory tests can accurately reproduce the main failures observed in the field. However, such lifetime tests can be time- and labor-intensive. To address this challenge, a data-driven method is proposed that predicts the lifetime of electrical connectors using statistical analysis of electrical contact resistance data collected from short-term tests. The predictions from this method were compared to actual results obtained from long-term tests. A strong correlation was observed between the contact resistance development in short-term tests and the number of failures in later stages of testing. Thus, apart from predicting the lifetime of connectors, this method can also be applied for failure prognosis in real-time operations.

System Study Review of Electrical Machines under Specific Operating Conditions of Power Installations

The problem of life cycle vulnerability, predetermined by the development stages, operation and modernization of electrical machines due tosize and weight restrictions, dynamic electromagnetic and thermal overloads, possible flooding and changes in ventilation and cooling conditionsis considered. Reducing the weight and size of electric machines implies eliminating passive sections of magnetic circuits and optimizing the ratio of copper and steel. The desire to reduce weight and size indicators and increase energy density entails increased heat generation and temperature loads of structural elements. The increase in operatingtemperatures of modern machines indicates the need to develop mathematical models that account the response of electrical materials and structural elements to the combined thermal and magnetic fieldeffects. Such models are in demand to study the temperature dependence of insulating, magnetic and operating properties of electrical machines when establishing the requiredoperating moderestrictions in order to preserve and extend the life cycle. The criterion for making management decisions aimed at changing operating modes during operation can be maximum loads that limit exceeding the maximum permissible temperatures of the electrical insulationclass used, as well as critical values of induction determined by the temperature dependence of ferromagnetproperties that affect the performance characteristics of electrical machines. Further solution to the problem lies in the creation of digital twins containing complete mathematical and computer simulation models that describe processes in electrical machines, taking into account the temperature dependence of materialphysical properties of structural elements being subjected to thermal, magnetic and electric fields.

Pengembangan Keahlian dalam Produksi Kopi Liwa Melalui Pelatihan Penggunaan Mesin

Training on using coffee machines was held to improve the skills of Gamba Kupi Liwa Community members in the coffee production process. Through a theoretical and practical approach, participants are introduced to the concept of using modern machines to increase the efficiency and quality of coffee products. Training involves theory sessions, practical demonstrations, as well as interactive discussions. The training methodology includes exposure to the basic concepts of using coffee machines, hands-on practical sessions using modern equipment, and case studies to demonstrate the application of concepts in the coffee industry. The evaluation was carried out to measure participant understanding and the impact of the training on Gamba Kupi Liwa Community coffee production. The results of the training showed significant improvements in machine usage skills, operational efficiency and product quality. Additionally, training creates a collaborative environment among community members, increasing their involvement in the development of the local coffee industry. Thus, this training not only develops technical skills, but also builds the foundation for sustainable growth in the coffee industry. The success of this training provides a positive view of the potential of the Gamba Kupi Liwa Community to become a major player in the coffee industry, creating a positive impact on the community's economy and society.

ПРОБЛЕМА ПОВЫШЕНИЯ НАДЕЖНОСТИ МАШИН И ОБОРУДОВАНИЯ

The basis for a satisfactory level of operability of modern machines and equipment of domestic production was and remains the engineering and technical service of equipment and the "Planned preventive maintenance and repair system of machines in agriculture." Timely implementation of mechanized processes and work with low reliability of agricultural machinery requires an increase in the level of reliability and serviceability of the fleet of machines and equipment. (Research purpose) The research purpose is increasing the operational reliability of modern agricultural machinery based on the development and implementation of proprietary technical service. (Materials and methods) Materials obtained as a result of the author's own research and data on the reliability of domestic machinery and equipment from open sources were used in the research. The following methods were applied: comparative assessments, analysis and synthesis of the results of a survey of the operational reliability of agricultural machinery and equipment in real-world operation, the effectiveness of using various forms and methods of organizing their production and technical service. (Results and discussion) It was determined that an increase in the level of operability and reliability of modern domestic equipment can be ensured only with a significant improvement in the quality of manufacturing machinery and equipment and with the direct participation of the equipment manufacturer in technical service based on the proprietary method of technical service. It was noted that the organization of corporate technical service is possible only when creating a corporate production and technological system of mechanical engineering. The solution of this problem by the forces and means of existing separate equipment manufacturing plants is not possible. (Conclusions) To improve the reliability of modern domestic technology, it is necessary to reorganize the existing system of separate manufacturing plants, create large machine-building firms and branded technical service centers.

РОБОТИЗАЦИЯ ПРОИЗВОДСТВА СЕЛЬСКОХОЗЯЙСТВЕННОЙ ТЕХНИКИ

Increasing labor productivity at agricultural engineering enterprises in modern conditions is impossible without the use of robots, which should replace human labor in technological operations with dangerous and harmful production processes. (Research purpose) The research purpose is evaluating the use of robotics by enterprises of the agricultural machinery industry in the production. (Materials and methods) Conducted an assessment of the use of robotics tools when visiting enterprises in the agricultural engineering industry. (Results and discussion) It has been established that for a sustainable presence and strengthening of their positions in the market, companies producing agricultural machinery are increasing the volume of research and development work on the designs and production technologies of modern machines. It was noted that an increase in labor productivity in modern conditions is impossible without the use of robots, which are designed to replace human labor at work with harmful and dangerous production factors in procurement, when cleaning blanks, with thermal and physical methods of surface treatment of products made of various materials, when painting, as well as in order to reduce defects. It was determined that the use of robotization tools by enterprises of the agricultural machinery industry does not exceed three percent of the total volume of technological operations performed. Robotics tools are used mainly in welding operations. Loading and unloading, replacement of working tools on numerically controlled machines, as well as many other technological operations remain practically not covered. (Conclusions) The conducted studies have shown that machine-building companies have large reserves for using robotics tools in performing technological operations in order to reduce production costs and increase labor productivity. As measures to support the introduction of robots into production, grants are allocated by the Russian Digital Economy and Skolkovo foundations, preferential loans through the industrial development Fund "Digitalization of Industry".

Using hardware-transactional-memory support to implement speculative task execution

Loops take up most of the time of computer programs, so optimizing them so that they run in the shortest time possible is a continuous task. However, this task is not negligible; on the contrary, it is an open area of research since many irregular loops are hard to parallelize. Generally, these loops have loop-carried (DOACROSS) dependencies and the appearance of dependencies could depend on the context. Many techniques have been studied to be able to parallelize these loops efficiently; however, for example in the OpenMP standard there is no efficient way to parallelize them. This article presents Speculative Task Execution (STE), a technique that enables the execution of OpenMP tasks in a speculative way to accelerate certain hot-code regions (such as loops) marked by OpenMP directives. It also presents a detailed analysis of the application of Hardware Transactional Memory (HTM) support for executing tasks speculatively and describes a careful evaluation of the implementation of STE using HTM on modern machines. In particular, we consider the scenario in which speculative tasks are generated by the OpenMP taskloop construct (Speculative Taskloop (STL)). As a result, it provides evidence to support several important claims about the performance of STE over HTM in modern processor architectures. Experimental results reveal that: (a) by implementing STL on top of HTM for hot-code regions, speed-ups of up to 5.39× can be obtained in IBM POWER8 and of up to 2.41× in Intel processors using 4 cores; and (b) STL-ROT, a variant of STL using rollback-only transactions (ROTs), achieves speed-ups of up to 17.70× in IBM POWER9 processor using 20 cores.

Comparative Study: Use of Learning Languages in Mastering Printing Machine Operation Competencies (Case Study of Indonesian and Malaysian Printing Study Programs)

The development of printing machines has undergone an extraordinary transformation along with advances in technology. One of the biggest advances in printing machine technology is the transition from traditional printing methods to digital printing. The production process becomes faster and more efficient. Today's printing machine technology is equipped with advanced features that improve print quality. Modern machines are equipped with intelligent control systems with operating language and instructions in English, human involvement in the production stage is absolute. This research uses descriptive qualitative analysis methods. The comparative study used two countries, Indonesia and Malaysia. As a result, Malaysian students who use English as the medium of instruction have the ability to understand printing machine operating instructions better than Indonesian students. Operating a printing machine has similar abilities to students from two countries. This study underscores the importance of integrating English into engineering curricula, with recommendations for improving Indonesian students' command of English.

Tuning the Actuator Line Method to Properly Modelling Tip Effects in Finite-Length Blades

The Actuator Line Method (ALM) is gaining popularity in wind turbine simulations, as it can better handle some of the challenging operating conditions experienced by modern machines, such as highly turbulent inflows, severe aero-elastic forcing, and complex rotor-to-rotor interactions. However, it still falls behind other medium-fidelity methods such as the Lifting Line Free Vortex Wake (LLFVW) when it comes to resolving tip vortices and their effect on the blade spanwise load profile. The reason for such behavior is still unclear. A recent study suggested that this issue can be solved by reducing the scale of the angle of attack (α) sampling and force insertion towards the tip, without the need of additional corrections. This study builds on these findings to further investigate how the ALM base formulation - in terms of α sampling and force insertion - can be tuned to properly describe tip effects. An in-house ALM tool was employed to simulate a finite, constant-chord, NACA0018 wing, for which high-fidelity blade-resolved CFD (BR-CFD) data are available as benchmark. In the first part of the work, different strategies are outlined, including a novel approach for the de-coupling of the angle of attack sampling step from the force projection one, here called DE-coupled LineAverage (DELA). Their accuracy and sensitivity to ALM numerical settings are assessed at a fixed wing pitch angle of 6°. The analysis is then extended to a wider range of blade pitch angles, benchmarking the new ALM formulation against BR-CFD, ALM with the Dağ and Sørensen correction, and LLFVW in terms of blade loads, tip vortex structure, and computational effort.

The Lipliner Sign: Potential Cause of a False Positive Focused Assessment with Sonography in Trauma (FAST) Examination

BackgroundThe focused assessment with sonography in trauma (FAST) examination plays an essential role in diagnosing hemoperitoneum in trauma patients to guide prompt operative management. The FAST examination is highly specific for hemoperitoneum in trauma patients, and has been adopted in nontrauma patients to identify intraperitoneal fluid as a cause of abdominal pain or distension. However, causes of false positive FAST examinations have been described and require prompt recognition to avoid diagnostic uncertainty and inappropriate procedures. Most causes of false positive FAST examinations are due to anatomic mimics such as perinephric fat or seminal vesicles, however, modern ultrasound machines use a variety of postprocessing image enhancement techniques that can also lead to novel false positive artifacts. Case ReportWe report cases where experienced clinicians incorrectly interpreted ultrasound findings caused by a novel mimic of hemoperitoneum: the “lipliner sign.” It appears most prominently at the edges of solid organs (such as the liver and the spleen), which is the same location most likely to show free fluid in FAST examination in trauma patients. Why Should an Emergency Physician be Aware of This?Clinicians who take care of trauma patients must be familiar with causes of false positive FAST examinations that could lead to a misdiagnosis of hemoperitoneum.

A method for determining the spectral relaxation functions of polymers under single stretching of micro samples

The principles of designing products made of the latest complex-structured polymer composite materials necessitate the need to take into account the large-scale structural effects determined by processes at the supramolecular and molecular levels of the polymer: relaxation, kinetic (breaking and recombination of chemical bonds), recrystallization of supramolecular structures, etc. The development of these processes is described by relaxation functions, which, in turn, can be calculated using the functions of relaxation time spectra. The purpose of the work was to develop a specialized equipment for testing micro-samples with a variable working part for uniaxial stretching along with the experimental technique and computational algorithms for processing the obtained measurement data, and experimental approbation of the developed approach to determining spectral relaxation functions. A method is proposed for estimating relaxation functions not at fixed stress levels within linear elasticity, at secant points of deformation diagrams, at fixed values of the linear elasticity modulus, but within an extended range of the sample deformation up to pre-rupture states. A set of test equipment designed for tensile tests of micro-samples with a thickness of the working part of 0.2 – 1.2 mm has been developed. The tooling can be installed on modern high-precision breaking machines. Tensile tests of polyethylene terephthalate micro-samples with a thickness of 50 and 175 μm were carried out taking into account the scale factor. A tensile test of micro-samples that are technologically stabilized by paper frames of a special shape is described. Diagrams illustrating the kinetics of changes in the spectral relaxation functions of oriented polyethylene terephthalate (PET) are constructed proceeding from the data of testing micro-samples with a constant strain rate. A method for using these diagrams in calculations of empirical relaxation time spectra is described. The results of testing micro-samples of polyethylene terephthalate are presented. Illustrative deformation diagrams of the studied polymer samples and calculated diagrams of functions of relaxation time spectra calculated according to the described method are given.

Experimental Investigation on the Impact of Graphite Electrodes Grain Size on Technological Parameters and Surface Texture of Hastelloy C-22 after Electrical Discharge Machining with Negative Polarity.

Electrical discharge machining (EDM) is a rapidly evolving method in modern industry that manufactures highly complex components. The physical properties of a tool electrode material are significant factors in determining the effectiveness of the process, as well as the characteristics of the machined surfaces. The current trend of implementing graphite tool electrodes in manufacturing processes is observed. Innovative material engineering solutions enable graphite production with miniaturized grain size. However, the correlation between the graphite electrode grain size and the mechanism of the process removal in the EDM is a challenge for its widespread implementation in the industry. This research introduces a new method to evaluate the impact of the graphite electrode grain size and machining parameters on the material removal effectiveness, relative tool wear rate, and surface roughness (Ra) of Hastelloy C-22 following EDM with negative polarity. The study utilized new graphite materials with a grain size of 1 µm (POCO AF-5) and 10 µm (POCO EDM-180). An assessment of the impact of the EDM process parameters on the technological parameters and the development of the surface roughness was carried out. Electrical discharge machining with fine-grained graphite electrodes increases process efficiency and reduces tool wear. Graphite grains detached from the tool electrode affect the stability of electrical discharges and the efficiency of the process. Based on the experimental results, mathematical models were developed, enabling the prediction of machining effects to advance state-of-the-art manufacturing processes. The obtained mathematical models can be implemented in modern industrial EDM machines as guidelines for selecting adequate machining parameters depending on the desired process efficiency, tool wear rate, and surface roughness for advanced materials.

In situ build surface topography determination in electron beam powder bed fusion

Electron optical imaging is the most promising process monitoring method in electron beam powder bed fusion. State of the art in modern machines is the installation of a single detector in the top center of the build chamber. Exemplary applications are the reconstruction of digital twins of manufactured parts to compare their dimensional accuracy or analysing the top surface of each layer to identify surface features like pores or material transport. Multi-detector systems are currently under research and have shown great potential in reconstructing the surface topography in situ. A recently developed ray tracing model, describing the image formation process, allows to formulate design guide lines for multi-detector systems and provides a method for the computation of the normal vector field of the build surface. This work utilizes the recent progress and presents a newly developed four-detector system and an updated computation chain, which enable build surface topography reconstruction in situ in every layer of a build process. The computation chain contains a normal integration algorithm, which employs Tikhonov regularization to cope with measurement irregularities. The integration method is validated with ex situ measured as-built surfaces. Additionally, first applications are demonstrated and connections to process parameter changes illustrated.