Technological Equipment Research Articles

Analysis of the third class mechanism using the modeling method in the Mathcad software environment

Purpose. To carry out a kinematic analysis of a flat twelve-link hinged mechanism with three leading links, the basis of which is a structural group of links of the third class of the fourth order with rotational kinematic pairs, which is used in technological equipment. Methodology. The kinematic study of a flat complex mechanism of the third class with three leading links was performed using the mathematical modeling method in the Mathcad software environment. Findings. Using the method of mathematical modeling, the mechanism was presented in the form of free vectors built on its links, for which, taking into account the presence of three leading links, three vector contours were selected, which made it possible to draw up a system of vector equations of their closedness with further solving by a numerical method in the Mathcad software environment. The functions of the rotation angles of the mechanism links, their angular velocities and accelerations were obtained in analytical and graphical form depending on the rotation angle of the first driving crank of the mechanism, the calculation of the angular velocities and accelerations of all the driven links of the mechanism was performed. Originality. A sequence was developed and a kinematic study of a complex planar mechanism of the third class with three leading links was done, the basis of which is a structural group of links of the third class of the fourth order. Schematic modeling of the mechanism with three leading links was performed, a visualization schedule of its kinematic scheme was built, and a valid version of its assembly was obtained from many possible ones, for which the values of kinematic parameters of all its links were determined. Practical value. An analysis of the effect of the kinematic parameters of the three leading links of the third-class mechanism on the movement of the working body of the technological equipment was carried out. From the analysis of the obtained research results for the cycle of the mechanism the reason was found for the incomplete technological stoppage of the link, which should provide the working body of the machine for the required period of time. Recommendations of the elimination were made to identify the deficiency and proposals for the need to improve the drive of this equipment.

Prevalence of Keratoconus and Keratoconus Suspect among a sample of Iraqi Children with Refractive Errors: A Cross-Sectional Study

Background: Keratoconus (KC) is a chronic, bilateral, non-inflammatory degenerative condition with severe consequences. Objective: To assess the prevalence of KC and Keratoconus Suspect (KCS) in a pediatric population with astigmatic error ≥1 diopter (D) and non-axial myopia. Methods: Between March and October 2022, a cross-sectional study was done with a group of 6–18-year-old kids with an astigmatic error of ≥1 D or non-axial myopia who went to the pediatric ophthalmology clinic at Ibn Al-Haitham Teaching Eye Hospital in Baghdad, Iraq, for regular checkups. All patients got a thorough eye examination and corneal imaging using the Corneal Tomography System (CSO) Sirius equipment and Scheimpflug technology. Results: The majority of patients were females aged 110–14 years (55%). The frequencies of KC and SKC were 13.5 and 119.6%, respectively. The proportion of KC was substantially higher for those above the age of 14. Patients with KC exhibited considerably larger cylinder and axis measurements. Participants with inferior cones and an asymmetric Bow Tie exhibited greater rates of KC (51.2% and 29.4%, respectively). Except for Pachy-Thin and corneal volume mean values, all other metrics were considerably greater in KC and KCS patients than in control patients. Conclusions: The high prevalence of KC and KCS emphasizes the importance of this issue and the necessity for a systematic strategy for screening in pediatric age groups with refractive error.

Application and Prospect of Strapdown Inertial Navigation System in Coal Mining Equipment

In recent years, with the rapid construction of a safe, clean, efficient and sustainable modern energy system, the intelligence of coal mining has become the inevitable direction of the development of the coal mining industry. The intelligence of coal mining system and equipment is the core of intelligent mining, and the positioning technology of mining equipment is the key to underground intelligent mining. The strapdown inertial navigation system can make up for the shortcomings of traditional GPS positioning systems and laser positioning because of its strong anti-interference, high precision and real-time monitoring, and ability to carry out real-time dynamic positioning of mining equipment in underground coal mines. This paper briefly introduces the basic principle of the strapdown inertial navigation system, analyzes the application of the existing strapdown inertial navigation system in mining equipment, and lists and analyzes the research status of the improvement strategy of the inertial navigation system, such as zero speed correction and integrated navigation technology. Finally, by analyzing the application and future development trend of inertial navigation systems in mining equipment, this paper provides more data and method support for the positioning of mining equipment in the future.

Thin-film electrodes of dielectric elastomer-based actuators for an active vibration control system

Precision research and technological equipment, as a rule, is not able to provide its specification characteristics without a high-quality vibration protection system. Active vibration control of an object is provided with the help of an additional source of movement, an actuator. The most promising high accuracy actuators are based on smart materials, such as materials with shape memory, piezoelectric and magnetostrictive materials, electro- and magnetic active fluids and elastomers. Dielectric elastomer is one of the types of electroactive polymers. Actuators based on a dielectric elastomer show high performance in terms of accuracy and speed and operate due to the controllable deformation of the elastomer under the action of a high voltage electric field. The paper provides a comparison of actuators based on sheet and thin film control electrodes. The influence of the quality of the polymer surface and the type of electrodes on the travel range of the actuator and maximum amplitude of vibrations the system can suppress on the basis of a dielectric elastomer is estimated. The formation of the electrode by magnetron sputtering in vacuum makes it possible to create a thin-film layer of copper that covers the elastomer, despite the developed surface. The effect of ion treatment of an elastomer before coating on the quality of the formed electrode is considered. After the ion treatment, the surface of the elastomer acquires a more uniform regular structure. A thin-film electrode layer is formed according to the topology of the elastomer to an accomplished standard.

Influence of the Deformation of the Thread Section in the Direct Contact Zone on the Value of Acceleration of the Central Axis Points

Determined projections of the acceleration vector in relation to the arc length coordinate of the thread axis through components that define the degree of thread compression in the contact zone. Solving the challenges faced by the textile and light industries in increasing the production of fabrics and knitted goods based on improving the productivity of existing equipment and employing modern technologies, grounded in the latest scientific achievements, has significant economic and technical importance. The number of breakages can be significantly reduced by using high-quality raw materials and optimizing the conditions of thread processing on technological equipment, where interaction with guiding and working elements of large and small curvature occurs. Theoretical foundations for the accelerations of points on the thread axis, considering compression during its movement along a guide of large curvature, have been developed.

Research on dynamic vibration absorption technology for power equipment based on energy degradation

Research on dynamic vibration absorption technology for power equipment based on energy degradation

Trajectory-based synthesis of a slider-crank mechanism for applications in inertial vibration exciters

Slider-crank mechanisms are widely used in various industrial and technological machines. This paper considers a generalized diagram of a slider-crank mechanism, on the connecting rod of which an imbalanced mass can be fixed. In such a case, the slider-crank mechanism can be employed as an inertial vibration exciter. The aim of this research is to justify the geometric parameters of the mechanism to ensure a predetermined elliptical trajectory of the imbalanced mass motion. The research methodology involves the analytical derivation of the motion equations for a connecting rod point and solving the problem of synthesizing the geometric parameters of the mechanism based on the given trajectory of this point. The obtained results are presented in the form of displacements and trajectories for the connecting rod point of a specific slider-crank mechanism. The major novelty of this research lies in the further development of the theory of slider-crank mechanism synthesis for use in inertial vibration exciters. The derived analytical dependencies can be utilized by designers and engineers in the development of new types of vibration exciters for various industrial and technological vibratory equipment.

Three-dimensional Change Detection and Description in Complex Construction Scenarios

Abstract. In large-scale engineering construction scenarios, construction objects and equipment are numerous; their spatial positions and postures change frequently and are complex and varied. Describing the changes between construction entities and the entities themselves in a three-dimensional (3D) geometric space and functional semantic space is challenging. In response to this challenging, we propose a novel workflow to detect and describe the changes in a construction site. First, we add the constraint of object surface continuity to the octree change detection (OCD), exclude the independently changing cells, and improve the change detection robustness. Second, based on the changes in entity elements that occur in the 3D geometric space, we introduce six-type semantics to characterize the changes that occur. Differing from existing change detection semantic description methods that focus on the attribute semantics of changed entity elements, our method focuses on the semantic description of the change process. Finally, for the variations in different semantic types, we propose specific quantization methods that can better quantify the variations in entity elements in 3D geometric space. For the proposed solution, we tested it using two sets of multi-period time-series point cloud data, which can accurately identify the changing construction entities in space and complete the calculation of bridge construction progress, including the building demolition and construction, and the change in the construction apparatus position.

Ultrasound for breast cancer detection: A bibliometric analysis of global trends between 2004 and 2024.

With the advancement of computer technology and imaging equipment, ultrasound has emerged as a crucial tool in breast cancer diagnosis. To gain deeper insights into the research landscape of ultrasound in breast cancer diagnosis, this study employed bibliometric methods for a comprehensive analysis spanning from 2004 to 2024, analyzing 3523 articles from 2176 institutions in 82 countries/regions. Over this period, publications on ultrasound diagnosis of breast cancer showed a fluctuating growth trend from 2004 to 2024. Notably, China, Seoul National University and Kim EK emerged as leading contributors in ultrasound for breast cancer detection, with the most published and cited journals being Ultrasound Med Biol and Radiology. The research spots in this area included "breast lesion", "dense breast" and "breast-conserving surgery", while "machine learning", "ultrasonic imaging", "convolutional neural network", "case report", "pathological complete response", "deep learning", "artificial intelligence" and "classification" are anticipated to become future research frontiers. This groundbreaking bibliometric analysis and visualization of ultrasonic breast cancer diagnosis publications offer clinical medical professionals a reliable research focus and direction.

Направления совершенствования сероочистки, осушки и переработки природного газа

The results of the work of the staff of the Department of “Chemical Technology of Oil and Gas Refining” of Astrakhan State Technical University in the field of separation of three-phase reservoir mixture, increasing the efficiency of desulfurization, improving the process of drying gas and the production of continuous hydrocarbons – raw materials for petrochemistry. The influence of the quality of raw materials entering processing on the formation of deposits in technological equipment has been studied. Reconstruction of the inlet and three-phase separators of high-pressure reservoir mixture separation plants by installing a vibration damper and a depulsor on the reservoir mixture supply line to the installation, as well as reconstruction of the input of raw materials into the separator of the installation. The use of the KPG-200 defoamer and the KPG-200 AV antifoamer made it possible to reduce the consumption rate of defoaming reagents several times in gas purification plants from acidic components. The influence of various impurities on the foaming of working amine solutions (mechanical impurities, coal dust, products of thermal destruction of amine, thermostable salts, corrosion inhibitors) has been determined. It was revealed that the products of thermal degradation of amine have the greatest effect at concentrations above 3% by weight. A method for reducing the content of mechanical impurities in a solution of diethanolamine in a constant magnetic field has been developed and introduced into an industrial desulfurization plant. The filtration efficiency increases 2.6 times, the foam height is halved, and the foam stability is quadrupled. At the same time, the activity of the defoamer increases by 1.7 times. The mathematical dependence of the height of the protective layer of aluminum oxide in an adsorber with zeolite on impurities of diethanolamine has been experimentally found. The effectiveness of the developed improved distribution ring device is shown, the use of which makes it possible to practically eliminate dead zones in the zeolite layer and thereby increase the efficiency of the adsorption process and increase the inter-regeneration period on the drying unit. Studies of the catalytic pyrolysis of the butane fraction using CVM-type pentasils modified with the introduction of chromium can reduce the process temperature compared with the thermal decomposition of raw materials by more than one hundred degrees 100 °C.

A lean approach to comparing the mooring systems of Suezmax tankers

AbstractMooring Suezmax tankers is a process requiring skilled ship crews and terminal workers to accomplish the time-consuming, hazardous task of securing the ship to a jetty to load or discharge oil cargoes. The advent of new equipment technologies has enabled industry professionals to view the mooring process from a new perspective. A lean approach is applied to analysing alternative mooring processes of Suezmax tankers. A reduction in mooring time of about 30 min is noted when replacing steel wire with high modulus synthetic fibre (HMSF) ropes. Further, a potential time saving of 57 min is noted if automated mooring is used instead of steel wire, and 27 min compared with HMSF. The automated mooring concept reduces the manpower required to perform the mooring process, both on board and ashore. If HMSF lines replace steel wires, a significant reduction is noted in ship and crew time costs incurred with mooring maintenance onboard during sailing. A single case study addresses the two research questions: (1) What is the mooring process of Suezmax tankers? (2) How can the mooring process of Suezmax tankers be enhanced?

Teaching Pronunciation to EFL Learners at the Tertiary Level: Perspectives of Professors at Saudi Universities

This study aimed to provide a novel, focused program for instructing English pronunciation to Saudi EFL university students, grounded upon identified mistake patterns. In addition, to execute the customized curriculum in pronunciation instruction for a group of Saudi EFL students. Furthermore, to evaluate the efficacy of the tailored curriculum by measuring enhancements in pronunciation accuracy. Additionally, to investigate the attitudes and experiences of EFL professors at various Saudi universities regarding the designated pronunciation curriculum using surveys. The researchers adopted the analytical-descriptive research method, utilizing the questionnaire as a tool for collecting data from thirty-three EFL university professors who teach English at different Saudi universities. The main findings of this study were: excessive focus on instructing individual phonemes, prioritization of suprasegmentals; overdependence on standardized evaluations. The significant levels of disagreement suggest that these techniques may not adequately meet the pronunciation requirements of Arabic EFL learners. Allocating time for pronunciation may possess some merit, while its execution necessitates additional investigation. The consensus on communicative instruction suggests potential for this methodology if effectively employed. Technological tools were regarded as beneficial instruments, consistent with studies on computer-assisted pronunciation instruction. The efficacy of customizing curriculum to address faults made by Arabic learners; Emphasis on pronunciation instruction within educational institutions. The main recommendations were adopting communicative instructional methodologies for teaching pronunciation enhances the growth of EFL learners, employing technological equipment acts as advantageous tools in enhancing pronunciation education, and additional comparison investigations and lectures must be undertaken to establish a correlation between the phonological systems of learners' native language and the target language.

Comparison and analysis of ophthalmic resources and service ability in Shanxi Province in 2014 and 2021

Objective: To compare and analyze the ophthalmic resources and service ability in Shanxi Province in 2014 and 2021, and to provide reference for the development planning of ophthalmology and eye care. Methods: In this cross-sectional study, a questionnaire survey was conducted among all ophthalmic institutions registered in the health administrative department in 11 cities of Shanxi Province by the end of 2014 and 2021 by using the National Ophthalmology Competency Resource Questionnaire (compiled by the Medical Administration and Hospital Authority of the National Health and Wellness Commission). The basic situations of ophthalmic institutions in 2014 and 2021, as well as the human resources, ophthalmic equipment configuration, technology and medical service capabilities, were recorded and compared. The chi-square test was used for statistical analysis. Results: A total of 270 questionnaires for 2014 were collected from 270 ophthalmic institutions, and 292 questionnaires for 2021 from 292 ophthalmic institutions. The institution categories in 2014 (197 general hospitals, 31 eye hospitals and 42 others) were statistically different from those in 2021 (182 general hospitals, 45 eye hospitals and 65 others) (P<0.05). The proportion of doctors with senior titles in ophthalmic institutions increased from 25.5% (346/1 358) in 2014 to 41.7% (580/1 391) in 2021, the proportion of senior technicians increased from 9.4% (14/148) to 25.3% (110/435), the proportion of doctors with junior titles decreased from 42.1% (572/1 358) to 26.5% (369/1 391), and the proportion of junior technicians decreased from 45.3% (67/148) to 39.1% (170/435). There was a significant difference in the distribution of professional titles between doctors and technicians in ophthalmic institutions (P<0.05). The number of doctors (130 to 28), nurses (152 to 50), technicians (33 to 11) and full-time optometrists (44 to 12) in the first-class ophthalmic institutions decreased, the increase of equipment with the ophthalmic A-ultrasound scan system, fundus camera and coherent optical tomography system (35.1%, 28.9% and 25.4%; P<0.05) ranked the top three, and the increase of performing the phacoemulsification procedure, intraocular lens implantation, intravitreal injection and iris surgery (30.2%, 24.7% and 20.7%; P<0.05) ranked the top three in 2021 as compared to 2014. Conclusions: The resources and service ability of ophthalmology in Shanxi Province developed in 2021 in comparison with 2014. However, there were some problems, such as changes in the type and structure of eye institutions, unreasonable proportions of professional titles, insufficient human resources in primary ophthalmic institutions, and slow improvement in the allocation of ophthalmology equipment and technical capabilities.

Exploring impacts of electricity tariff on charging infrastructure planning: An activity-based approach

In the past decade, electric vehicles (EVs) have gained popularity for their efficiency and environmental benefits. Advances in battery technology and charging equipment have yielded long-range EVs and fast-charging. However, many major cities lack adequate charging infrastructure for daily EV use. This study addresses this gap by integrating activity-based modeling, charging behavior simulation, and charging infrastructure optimization. The research utilizes the POLARIS agent-based transportation model to accurately capture user activities, trip patterns, and traffic flows. Additionally, the study investigates the impact of fixed and spatiotemporal electricity rate distributions on optimal charging infrastructure deployment. The framework is applied to the Chicago regional area network and analyzed under various EV ownership scenarios. The results reveal significant impacts of the charging pricing strategy on user decision-making and charging demand distribution. There is also a need for consistent pricing policies in charging infrastructure planning and operational phases to avoid drops in service quality.

Selection of technological basis for intelligent anti-corrosion coating for protection of oil refining equipment

Subject of research: intelligent coating to protect oil refining equipment from corrosion, its protective and operational properties. Purpose of research: to develop the composition of an intelligent coating to protect oil refining equipment from corrosion, to study its basic operational characteristics, to test protective properties in aggressive environments. Methods and objects of research: samples made of 09G2C steel used for the manufacture of technological equipment of oil refineries and petrochemical plants, coated with various protective compositions to determine the main characteristics of the composition of the intelligent coating. To study the operational properties, a technique has been developed using magnetic stirrers that simulate the repeated interaction of a corrosive medium with samples. Main results of research: according to the results of climatic tests and chemical resistance of coatings in a corrosive environment, the most effective composition of the base of an intelligent coating with the best protective characteristics has been established and its necessary adhesive properties have been determined.

Roundtable: On Gaza and the War on Palestinian Journalism

This virtual panel discusses Israel’s war on Palestinian journalism, which has been part and parcel of its war on Gaza since October 7, 2023. Israel’s killing of Palestinian journalists has made this the deadliest period for journalists since the establishment of the Committee to Protect Journalists in 1992. Israel has also targeted and destroyed the instruments integral to reporting, including journalists’ equipment, cars, and communications technology, and it has imprisoned Palestinian journalists in unprecedented numbers. It has tried to limit coverage of the war by prohibiting foreign journalists from entering Gaza independently. This panel presents firsthand accounts from journalists and free speech advocates of their experiences covering the war on Gaza from their respective locations, including while living in constant danger in Gaza. It expresses Palestinian journalists’ commitment to speaking the truth despite extraordinary risks and conveys the importance of presenting reporting from Gaza under Palestinians’ own bylines.

МЕТОД ТА ДОСЛІДЖЕННЯ ТОЧНОСТІ ОБЧИСЛЮВАННЯ МАТЕМАТИЧНОЇ МОДЕЛІ ЕЛЕКТРОГІДРАВЛІЧНОГО ЕФЕКТУ

The mathematical model of the electrohydraulic effect (EHE) is a nonlinear non-stationary system of partial differential equations (PDE), which reflects the motion and contact interaction of two media, gaseous and liquid, under the action of pulsed thermal excitation. Such PDE systems generally do not have analytical solutions and are solved only by numerical methods, which are approximate in nature, i.e. they provide a solution with some error. The peculiarity of the motion of media in the case of EHE is large deformations in the form of flows and vortices. This feature imposes significant restrictions on the choice of the method for solving the PDE model. The widely known Lagrangian finite element method used to solve contact problems, in the case of EHE modeling leads to a pathological change in the shape of the finite elements, and therefore to instability of the calculation process and an unlimited increase in error. In calculation practice, a variant of the finite element method, FEM-ALE, has become widespread. It uses both Lagrangian and Eulerian grids of nodes and a special advection procedure, i.e., transfer by interpolation of the solution from the Lagrangian grid to the Eulerian one, and then vice versa from the Eulerian one to another new Lagrangian grid. Such an additional interpolation procedure, which is used repeatedly in the calculation, leads to additional (in comparison with the Lagrangian FEM) errors. If the causes and kinetics, as well as the methods of error control in the case of the Lagrangian FEM, have been sufficiently studied in the literature, then the kinetics of error development in the simulation of the EGE using the FEM-ALE method has been practically not studied. The article is devoted to the study of the development of errors in the numerical solution in this particular case. An analytical solution of the problem in the asymptotic case for a technological system with a rigid chamber is obtained. This solution is analyzed in comparison with the numerical solution using the FEM-ALE method. Conclusions are made regarding the errors in calculating pressure as the main factor of mechanical impact of EGE on the technological object and technological equipment, as well as errors in calculating deformations of gaseous and liquid media.The scientific novelty consists in the development of a method for determining the accuracy of EHE parameter calculations using the MSE-ALE method. The practical value lies in determining the accuracy of calculating the parameters of the EHE mathematical model, which makes it possible to justify the use of numerical modeling as a method of researching technological processes and systems using EHE

Damage to Special-Purpose Ring Wavy Springs under the Influence of Hydrogen Sulfide-Containing Media

Annular wavy springs are widely used in the oil and gas industry and most often serve either as compensators for temperature deformations or for mechanical seals of various joints in equipment transporting oil and gas media. These springs provide high load capacity with a relatively low draft, which ensures a compact design. Most often, such springs are made by stamping from sheet steel. When operating technological equipment that transport hydrogen sulfide-containing oil and gas media, hydrogen sulfide stress corrosion cracking occurs quite often, which can lead to failure of industrial equipment. In particular, damage to annular wavy springs can cause depressurization of elements of industrial equipment and cause significant harm not only to the environment, but also to maintenance personnel. The object of research was annular wavy springs made of steel type X15N7M2YU. The purpose of the study is to determine the resistance of the spring material to stress corrosion cracking. This article discusses the test results of special purpose annular wavy springs in an aggressive hydrogen sulfide-containing medium artificially prepared according to the recommendations of ANSI/NACE TM 0177. The results of hardness studies, strength calculations and metallographic studies of damage to a wavy spring are presented. The chemical composition of the metal of the spring fully corresponds to the steel type X15N7M2YU declared by the enterprise. According to the studies conducted in environments containing hydrogen sulfide, the wavy spring is not recommended for use in oil and gas equipment, since it is not resistant to hydrogen sulfide cracking under stress.

Improving parameters for achieving uniform cylindrical cup wall thickness in two-step deep drawing processes with SPCC sheet material

Deep drawing processes are essential in modern manufacturing for creating intricate components with deep hollows, particularly cylindrical forms. These processes are widely used in industries such as household appliances, automotive manufacturing, aerospace engineering, and fire safety equipment. This study focuses on the two-step deep drawing of cylindrical cups, utilizing both simulation and experimental methods. The primary goal is to determine optimal geometric and technological parameters for mold design and to address issues like wrinkling and tearing. Key parameters, including punch nose radius (Rpf), die nose radius (Rdf), punch-die clearance (Wf), and blank holder force (BHF), are systematically analyzed. Results show that proper parameters lead to a uniform wall thickness, with deviations reduced to 4.77%. Conversely, improper parameters result in a 12.03% deviation. Improved parameters in the second-step deep drawing yield cylindrical cups that closely match experimental outcomes, free from wrinkling or rim cracking. This research highlights the importance of selecting appropriate parameters to avoid defects.

Development of structural and technological solutions for the construction of large-span coatings by craneless methods

The article presents an analysis of the method of lifting large-span coatings using the pushing and pulling methods and introduces a new structural-technological solution for erecting coatings using mechanized technological equipment in the form of a lifting module. According to the solution, the load-bearing beams of the coating are moved in the space between paired columns of the frame, resting on the lifting modules. Guide profiles fixed to the inner surfaces of the columns serve as supports for the alternating support of the platforms of the lifting module, which pushes the coating beams in the inter-column space. The developed solution optimizes the lifting processes and reduces the duration of lifting works by minimizing the number of installations works to operations for fixing the beams of the coating at the design height and automating the processes of pushing the coating with lifting modules.