Equipment Manufacturers Research Articles

INSTALASI PEMBUMIAN DAN INSTALASI LISTRIK MUSHOLA AL MUTTAQIIN TEMBESI KIBING-BATU AJI BATAM

The condition of the electrical installation system in people's homes and especially places of pray (Mushola) in Tembesi Kalurahan Kibing, Batu Aji District, Batam City, most people still do not understand about electrical installations and there are still many things that do not comply with general regulations regarding electrical installations, apart from There are still many electrical installation connections carried out by the community themselves which do not comply with the provisions. Community service by providing counseling and going directly to see the location that is the target for carrying out service activities, namely the Al Muttaqiin prayer room. By holding community service (PKM), residents of Kibing Village will understand how to install electricity properly, correctly and safely. The equipment selected for installation in an electrical installation must meet applicable standards and must be suitable for its environment. Installation of equipment must comply with the provisions in PUIL, and match the equipment manufacturer's instructions. Electrical installations must be regularly inspected and tested for misuse, damage or poor installation, including loose connections. To protect against leakage currents, grounding and ELCB can be installed.In order to achieve an increase in public knowledge and understanding about the importance of electrical hazards, this activity needs to be sustainable

ADDITIVE TECHNOLOGIES IN CONSTRUCTION: TECHNICAL, ECONOMIC AND MANAGEMENT ANALYSIS

The study is devoted to a comprehensive analysis of the introduction of additive technologies into modern construction production, revealing the technical, economic, and managerial aspects of concrete 3D-printing of architectural structures. The work systematically analyzes the evolution of additive manufacturing technologies and identifies the main structural types of 3D-printers (an additive machine for layer-by-layer construction of objects), including portal, robotic, mobile, and hybrid systems. A detailed study of the technological parameters of concrete 3D-printing with concrete mixtures is presented, in particular, optimal printing speed modes, layer parameters, criteria for shaping and quality of building structures. A comparative analysis of the technological capabilities of leading world equipment manufacturers, such as ICON, COBOD International, Apis Cor, and WinSun, is conducted. The economic analysis demonstrates significant advantages of additive technologies: reduction of construction time by 2-6 times, reduction of construction cost by 20-35%, and increase in the load-bearing capacity of structures. The study comprehensively explores the structure of capital and operational expenses associated with technology implementation. Special emphasis is placed on the management aspects of introducing additive technologies, highlighting the critical need for an interdisciplinary approach and knowledge integration across architecture, engineering, management, and computer modeling. The study determines the prospects for the development of concrete 3D-printing technology in the construction industry and outlines the main directions of further scientific research and practical implementation of innovative solutions. This study was developed between the Department of "Integrated Technologies of Mechanical Engineering" named after M. Semko of NTU "KhPI" and "Geopolimer" LTD to implement innovative technologies in the construction industry.

EVALUASI CYCLE TIME TERHADAP KONDISI MEDAN PADA PROYEK PEMBANGUNAN AKSES JALAN SAMOTA LANJUTAN KABUPATEN SUMBAWA

The Samota Road access development project continued in Sumbawa Regency is one part of the Samota area development project which acts as access to mobilization and supports the acceleration of development, economy, social and culture. In large-scale road works, heavy equipment is needed to facilitate work in a relatively shorter time. Errors in the operating time of heavy equipment and differences in the work field will affect cycle time and have an impact on productivity. This study aims to determine the amount of heavy equipment cycle time, heavy equipment productivity, and the effect of cycle time on heavy equipment productivity. The methods used in this research are time study and correlation methods. The time study method is a measurement of work by collecting data based on the time needed to complete a job so that productivity can be calculated, while the correlation method is an analysis to determine the level of relationship between the independent variable (X) and the dependent variable (Y).Based on data analysis, the value of cycle time, productivity and the effect of cycle time on heavy equipment productivity were obtained. In segment 1, the cycle time of the motor grader is 303,247 seconds with a productivity of 916,037 m2/hour and the cycle time of the vibratory roller is 612,345 seconds with a productivity of 1061,400 m3/hour. For the effect of cycle time on the productivity of the motor grader, the correlation test result is 0,986 and the vibratory roller is 0,999. In segment 4, the motor grader cycle time is 316,107 seconds with a productivity of 831,112 m2/ hour and the vibratory roller cycle time is 655,370 seconds with a productivity of 988,200 m3/hour. For the effect of cycle time on motor grader productivity, the correlation test results were obtained at 0,975 and vibratory roller at 0,999. In both segments, there is a very strong influence and relationship between variable X (cycle time) and variable Y (productivity).

Research on Transformation and Upgrading of Equipment Manufacturing Industry and Optimization of Tax Policy Discrepancy: Case of Hebei Province

Operating income of Hebei equipment manufacturing industry exceeded one trillion yuan. In order to further promote the transformation and upgrading, in recent years, the Hebei Provincial Tax Bureau of the State Administration of Taxation has implemented and continued a series of national tax support policies and achieved phased results. However, due to some objective and realistic factors, Hebei equipment manufacturing industry is still lacking. This research takes different stages of enterprise operation as nodes, and gradually sorts out, studies and analyzes the current tax policies according to the links. The results highlight the effectiveness mechanism of the current tax policies for the development of equipment manufacturing industry based on the research. Moreover, based on a variety of real data found in this paper, the data of Hebei equipment manufacturing industry is compared in multiple dimensions to objectively present problems and shortcomings. This paper focuses on the transformation and upgrading of Hebei equipment manufacturing industry and tax policy in a small-cut view and makes policy optimization suggestions based on the tax policy gap, in order to provide reference for the better development of Hebei equipment manufacturing industry.

Driving productivity: a comparison of the Indian automobile manufacturers and component suppliers

ABSTRACT This study analyzes the factors influencing productivity within the Indian Automobile industry, specifically examining the component manufacturers and the original equipment manufacturers (OEMs). Utilising a dynamic panel data model, we assess the effects of lagged R&D stock, trade dynamics, and firm-specific factors on total factor productivity spanning the period 2000–2023. Our findings underscore the significant impact of a firm’s lagged R&D stock, lagged export intensity and the import of embodied and disembodied technology in the industry. While lagged export intensity plays a significant role in improving productivity, with a greater impact on the OEM segment, the influence of technology imports differs across both segments. Specifically, OEMs benefit more from the import of embodied technology or capital equipment, while the component segment from disembodied technology or royalty payments and licensing. We also find that electric vehicle penetration has a significant positive impact on the productivity of the OEM segment alone, indicating that the benefits of the new technology do not have a visible impact on the industry as a whole. These results highlight distinct patterns in technological learning between the two segments, unveiling structural variations within the industry.

Broken Drill Bits During Surgical Procedures: A Review of 156 Patient Safety Events

Background Broken surgical drill bits pose a risk to patient safety. A routine review of event reports submitted to the Pennsylvania Patient Safety Reporting System (PA-PSRS) uncovered an increase in the number of event reports related to broken drill bits, prompting an exploration to better understand patterns of drill bit breakage in Pennsylvania. Methods We queried the PA-PSRS database to identify event reports describing a broken drill bit during surgery submitted between January 1, 2021, and December 31, 2023. Event reports were manually coded to identify the procedure, anatomic location of breakage in the patient’s body, timing of discovery, and fragment fate. Results A total of 156 relevant event reports were identified. The procedure being performed was determined in 64 of 156 event reports. Fracture repair procedures were most commonly reported to encounter a broken drill bit (27 of 64; 42.2%). We were able to determine the anatomic location in the patient’s body where the drill bit breakage occurred in 108 of 156 event reports. The most commonly reported anatomic location was the femur (27 of 108; 25.0%). We were able to determine the fate of the broken drill bit in 141 of 156 event reports, and most drill bits were retained in the patient (99 of 141; 70.2%). Conclusion This data analysis provides insight into broken drill bits in Pennsylvania facilities. Because drill bits are commonly broken pieces of equipment and the fragments from these broken pieces are frequently retained, it is important to prevent drill bit breakage to improve patient safety. Table 2 (251188) outlines prevention strategies established by equipment manufacturers and previous research. Implementing these strategies can address breakage across multiple procedures and patients. Plain Language Summary While a rare occurrence, surgical instruments may break during a procedure. In the case of drill bits, which are one of the most frequently broken surgical instruments, pieces that are left inside of a patient could cause harm, and may migrate to other parts of the body. When Patient Safety Authority researchers noted an increased number of events involving broken and retained drill bits during surgery, they analyzed data from the Pennsylvania Patient Safety Reporting System (PA-PSRS) to help decrease the risk of broken drill bits in surgery. In studying cases involving a drill bit breaking during surgery, researchers learned that most of these events occurred during fracture repair procedures and joint replacement surgery, and drill bits most frequently broke in the femur (thigh bone). In most event reports, the broken drill bit was discovered during the procedure, but in 2.6% of event reports (4 out of 156 reports) it was discovered after the operation. Removing drill bit fragments is recommended; however, surgeons may decide to leave them in place if removal risks damage to the surrounding area, and in many event reports broken drill bits were retained following the surgery with no further intervention. Hospitals and surgical facilities should look to existing literature and device manufacturers’ guidelines for prevention strategies, such as recommended surgical techniques; drill bit sterilization, reprocessing, and storage; and general safety measures, some of which are summarized in the article.

Longitudinal Monitoring of Electric Vehicle Travel Trends Using Connected Vehicle Data

Historically, practitioners and researchers have used selected count station data and survey-based methods along with demand modeling to forecast vehicle miles traveled (VMT). While these methods may suffer from self-reporting bias or spatial and temporal constraints, the widely available connected vehicle (CV) data at 3 s fidelity, independent of any fixed sensor constraints, present a unique opportunity to complement traditional VMT estimation processes with real-world data in near real-time. This study developed scalable methodologies and analyzed 238 billion records representing 16 months of connected vehicle data from January 2022 through April 2023 for Indiana, classified as internal combustion engine (ICE), hybrid (HVs) or electric vehicles (EVs). Year-over-year comparisons showed a significant increase in EVMT (+156%) with minor growth in ICEVMT (+2%). A route-level analysis enables stakeholders to evaluate the impact of their charging infrastructure investments at the federal, state, and even local level, unbound by jurisdictional constraints. Mean and median EV trip lengths on the six longest interstate corridors showed a 7.1 and 11.5 mile increase, respectively, from April 2022 to April 2023. Although the current CV dataset does not randomly sample the full fleet of ICE, HVs, and EVs, the methodologies and visuals in this study present a framework for future evaluations of the return on charging infrastructure investments on a regular basis using real-world data from electric vehicles traversing U.S. roads. This study presents novel contributions in utilizing CV data to compute performance measures such as VMT and trip lengths by vehicle type—EV, HV, or ICE, unattainable using traditional data collection practices that cannot differentiate among vehicle types due to inherent limitations. We believe the analysis presented in this paper can serve as a framework to support dialogue between agencies and automotive Original Equipment Manufacturers in developing an unbiased framework for deriving anonymized performance measures for agencies to make informed data-driven infrastructure investment decisions to equitably serve ICE, HV, and EV users.

DARI PISANG MENJADI PELUANG: STRATEGI PENINGKATAN USAHA KERIPIK DI SURABAYA

This PKM activity supports one of the main focus areas of Community Service 2024, namely the Green Economy sector in the use of composter tubes to process banana waste into fertilizer. The partner in this PKM is Mr. Sukri, owner of the JOYO banana chips business, located at Pakal Madya Jaya 5 no 11A RT 03 RW 02 Pakal Village, Pakal District, Surabaya City, which is 2.2 KM from the UWP campus. The urgency of this activity is low production capacity and the products produced are not good so it requires a touch of science and technology. The aim of this activity is to increase partner production capacity and quality and increase partner turnover. Priority problems, namely, in the Production sector, production equipment is still traditional and not ergonomic, wastes fuel, unhealthy and dirty inventory space and lots of rodents, workers do not wear PPE: Marketing sector, sales are unstable, packaging still uses thin plastic, labels and brands are less attractive, in the field of Business Management, there is no financial record keeping and there is no understanding of food health. The solution offered is to increase the quality and capacity of the business through developing banana chips TTG, increasing business capabilities, expanding marketing, improving packaging, labels and brands as well as financial records. Implementation method with TTG development of banana chips machine, partnership, training and mentoring. The results of the implementation of activities in this program include coordination of program implementation with partners, dissemination of TTG Banana Chips Machines, procurement of equipment and training on healthy production, dissemination of TTG Waste Processing Composter Tubes, online and offline sales training and assistance, training and assistance in making labels and logos , training and assistance in recording business financial transactions. The impact of this activity is an increase in the capacity and quality of partner products by 30%, an increase in partner turnover by 30%, an increase in partner knowledge and skills by 50%.

Barriers and recommendations for the implementation of robot-assisted minimally invasive surgery in Africa.

Robotic surgery offers several advantages to the African setting, including shorter hospital stays, faster return to work, and increased overall productivity. However, its adoption has been limited by several factors. This review aims to present the barriers to implementation, and recommendations for integrating robotic surgery into the African healthcare system. Use of robotic surgery in Africa is primarily limited to Egypt and South Africa. Barriers faced by other countries were categorized into economic, infrastructural, systemic, and training-related. They include limited healthcare budgets, initial costs of robotic systems, patients' inability to afford robotic procedures, out-of-pocket healthcare financing, inadequate power supply, limited internet connectivity, poor healthcare leadership, and insufficient surgeon training facilities. Public-private partnerships, provision of loans and subsidies, introduction of cheaper robotic systems, and local manufacturing of robotic equipment will serve as cost-effective innovations. It is also important to improve healthcare financing and strengthen healthcare leadership across Africa. To address the lack of surgeon training facilities, remote assistance for surgeon training can be used to create a mentor-mentee relationship between robotic surgeons in any part of the world and surgical trainees in Africa to facilitate knowledge transfer. Prior investment in electricity and network infrastructure is however necessary. Establishment of fellowships to provide early exposure to robotic surgery should also be explored. AI-integrated robotic surgery can also enhance precision and safety, and provide tailored training tools for surgeons. Similar barriers to the adoption of surgical robotics are faced across Africa. By implementing the provided recommendations, robotic surgery can still be widely adopted in African settings, despite the delay.

Optimized Scheduling Model Considering the Demand Response and Sequential Requirements of Polysilicon Production

The polysilicon production process has significant potential to be made adjustable, and actively changing its production schedule to participate in grid dispatch can effectively alleviate the pressure on the power supply and balance demand while promoting renewable energy consumption. Considering the complex inter-coupling relationship between the sequential requirements and adjustable potential of polysilicon production, this paper analyzes the electricity consumption characteristics of various stages of a polysilicon production process that uses the improved Siemens method as its primary approach to production. The interaction between the polysilicon production process, equipment, and materials is modeled through the state–task network method, and the production timing requirements are transformed into constraint expressions. An optimized scheduling model that includes the production’s sequential requirements within a time-of-use electricity pricing context is established. Our analysis shows that the proposed model can formulate a feasible production plan with the lowest power purchase cost for polysilicon plants while meeting the production’s sequential requirements and product order demands.

Analysis of work productivity and compatibility of excavation-loading equipment and transport equipment in soil salvaging activities at Katala Hill area of PT. Amman

Abstract PT. Amman Mineral Internasional Tbk in Katala Hill, West Nusa Tenggara Province, Indonesia, is an open-pit mining company producing copper as its main commodity, followed by gold and silver. The initial stage of mining involves soil removal in land clearing activities for reclamation, waste disposal areas, and construction of other infrastructure. In soil salvaging activities, it is essential to understand the influential factors to productivity and the match factor in mechanical equipment, including work efficiency, delay time, cycle time, fill factor, and swell factor. The objective of this study is to determine the productivity and match factor values of the digging-loading equipment and transportation equipment in soil salvaging activities in the Katala Hill area. This study applied the descriptive quantitative method, involving direct field observations of the digging-loading and transportation equipment activities and interviews with mining workers. Based on the results, the actual work efficiency of the digging-loading equipment was 59% and the transportation equipment was 76%, the actual productivity of the digging-loading equipment was 825.00Bcm/h, the transportation equipment productivity was 611.17 Bcm/h, and the compatibility factor value is 0.7408. After increasing the work efficiency of the conveyance by 83%, the conveyance productivity was 667.46 Bcm/h with the match factor increasing to 0.8090.

Mining Area Production Safety Optimization Based on Multi-objective Particle Swarm Optimization Model

Safe production in metal mines is an important task to ensure the safety of workers and the integrity of production equipment. From the perspective of optimization, this paper establishes an early warning model and a multi-objective particle swarm optimization algorithm model by analyzing the relevant production data affecting the indicator system of mine safety production, and then solves the model through the multi-objective particle swarm optimization algorithm to give an optimization scheme for maximizing the safety production of the relevant mines. For the safety production problems in metal mines, four indicator systems are proposed, namely, production ecological environment safety, production personnel safety standards, production equipment safety and production information security, and then the relevant production data of the four indicator systems are analyzed and the early warning model is established. Based on the relevant production data of the four indicator systems, the mathematical relationship between the production data affecting each indicator system is constructed. Then, a multi-objective particle swarm optimization algorithm is established to construct the relationship between the maximum safe production of the mine and each indicator system, and the index of the maximum safe production production data of the mine is obtained. The feasibility of the mine safety production optimization scheme is given.

The Microstructure and Wear Properties of Ni-coated and Agglomerated-Sintered WC-10Ni/316 Composite by Laser Melting Deposition

WC-10Ni particle-reinforced stainless steel matrix composites have potential applications in aerospace, energy engineering, automotive manufacturing, and marine engineering equipment. However, there is currently insufficient research on the integrated manufacturing and comparative analysis of Ni-coated (WC-10Ni)1.5/316 and agglomerated-sintered (WC-10Ni)1.5/316 composites using Laser Melting Deposition (LMD) technology. In this work, the fabrication and examination of the LMDed specimens are conducted to determine the influence of the forming process of particle reinforcement on the microstructure and wear properties of WC-10Ni/316 composites. The microstructure, phase composition, composition distribution, microhardness, and wear resistance of the two composites were comparatively analyzed using confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), microhardness tester, X-ray diffraction(XRD), energy-dispersive spectroscopy (EDS), and a reciprocating wear tester. The results indicate that the microstructure of Ni-coated (WC-10Ni)1.5/316 composite specimen contains a higher quantity of undecomposed Ni-coated WC-10Ni particles, with a lower proportion of precipitates, and dendrites predominantly exhibit an elongated dendrite morphology. In contrast, the agglomerated-sintered (WC-10Ni)1.5/316 composite specimen features a greater content of decomposed agglomerated-sintered WC-10Ni particles, a higher content of precipitates, and dendrites mainly present as slender dendrites. Both composites consist of phases such as γ-(Fe, Ni, Cr), WC, W2C, Fe6W6C, M6C, and Cr23C6. The undecomposed WC-10Ni particles and tungsten precipitates significantly enhance the microhardness and wear resistance of the specimen. Specifically, the Ni-coated (WC-10Ni)1.5/316 composite specimen displays a microhardness of 350.2±3.3 HV1.0, with a wear rate of 1.5797±0.0455mg/(N·km). Meanwhile, the Agglomerated-sintered (WC-10Ni)1.5/316 composite specimen reveals an average microhardness of 410.9±6.1 HV1.0 and a wear rate of 0.8057±0.0352mg/(N·km).

Association of Work Engagement With the Occurrence of Presenteeism in Heavy Equipment Manufacturing Male Workers in Jakarta-Indonesia.

Presenteeism, a detriment to productivity, is theorized to be associated with work engagement. However, this relationship remains unexplored among Indonesian manufacturing workers. This study aimed to determine the relationship between work engagement and presenteeism in heavy equipment manufacturing workers. This cross-sectional study collected data from 109 workers employed at a heavy equipment manufacturing firm in Jakarta, Indonesia. Presenteeism was evaluated through the Quality and Quantity (QQ) method questionnaire, and work engagement was assessed using the Indonesian version of the Utrecht Work Engagement Scale 9 (UWES-9) questionnaire. Respondents exhibited high work engagement score (median = 5.55) and low presenteeism score (median = 10), showing a significant negative correlation (r = -0.381) between the two. The high work engagement observed among heavy equipment manufacturing workers in Indonesia correlates with a low occurrence of presenteeism.

Maximizing circular economy benefits for manufacturing companies: A simulation tool for defining and implementing a circular product strategy

Achieving a balance between reducing environmental impact and ensuring economic viability is essential for Originals Equipment Manufacturers adopting circular product strategies. A critical aspect of this process is determining the optimal time to take a product out of operation to facilitate the implementing of an appropriate circular strategy. However, decision-makers often lack the tools and methods to effectively answer this question, making it difficult to define and implement a strategy that is both ecologically sound and economically viable. This article presents a methodology that uses the State of Health of a product as a key indicator to identify the most advantageous year for taking back the product and applying a specific circular process (i.e., reuse, remanufacturing or recycling). Based on the State-of-Health, the environmental impact and total cost of the product are calculated annually over its lifetime using defined parameters. A circular strategy is proposed for each take-back year, determined by State of Health thresholds for various circular processes. To determine the optimum take-back year, an algorithm is applied, using a weighted sum as the objective function. This methodology is implemented within a dynamic circular strategy simulation tool to support decision-making for stakeholders. The approach is demonstrated using a case study on a circuit breaker in Genset and hospital applications. The results show environmental and economic benefits of up to 7 % and 18 %, respectively, highlighting the potential value of using this circular strategy simulation tool.

The impact of low-molecular carboxylic acids on carbon dioxide corrosion of steel in underground gas production equipment in the Dnipro-Donetsk basin fields

The impact of low-molecular carboxylic acids on carbon dioxide corrosion of steel in underground gas production equipment in the Dnipro-Donetsk basin fields

ESTIMATION OF LOADING AND HAULING EQUIPMENT PRODUCTION AT PT. BAGUS JAYA ABADI, SORONG CITY, SOUTHWEST PAPUA PROVINCE

Bagus Jaya Abadi is a mining company located in Sorong City, Southwest Papua Province that uses quarry mining to extract andesite rock. The effectiveness of production equipment, such as excavators and dump trucks, is essential to meet production targets. However, operational challenges and weather conditions often hinder the achievement of these targets. This study aims to calculate the daily production rates of Caterpillar 320D and Komatsu PC 200 excavators when loading Hino 300 and Hino 260 dump trucks and evaluate the work efficiency of these machines. Results indicate that daily production rates for different equipment combinations vary between 145.36 m³/day and 221.93 m³/day, depending on the pairing of machinery. These findings provide a foundation for the company to improve production efficiency and develop strategies to address existing challenges.

Mobile base station site as a virtual power plant for grid stability

Energy grids and markets are in transition. Increased use of renewable energy sources (RES) introduces new stability challenges for power grids. Despite the substantial electrical consumption of mobile networks, they are yet to harness their inherent flexibility for aiding in the stability of the power grid. A noticeable research gap exists concerning measuring full activation time for fast frequency reserve (FFR) product while using batteries from mobile network base stations. Our objective is to demonstrate that mobile operators could use their existing infrastructure to participate in the reserve market of a contemporary power grid. Furthermore, it seeks to determine if the full activation time can meet the requirements of an FFR product. The system consists of a live mobile base station site with a mobile connection to the site, local controller, an existing battery, and a power system that, in combination, can function as part of a power grid balancing system. Our main finding indicates that the rectifier reaction time within an installed base station site infrastructure ranges from 5 to 8 s, and the time when the base station is entirely off from the grid varies from 7 to 10 s. This finding is significant since the activation time is too long for the base station power system controller to be used for FFR. The required full activation time for FFR is less than 1.3 s. In conclusion, power system vendors should investigate improvements for their equipment and software products to enable fast reserve market entry for their existing customers and stay competitive.

Recovery of elemental arsenic from calcium arsenate slag by carbothermic reduction: Ca3(AsO4)2 → Ca3(AsO3)2 → As4(g) pathway

With the increasing application of As(0) in semiconductor, equipment manufacturing fields, recovery of As(0) from hazardous wastes-bearing arsenic has attracted great attention. As alkali leaching method is widely used for disposal of wastes-bearing arsenic, secondary arsenic pollution has become an inevitable environmental problem due to the generated calcium arsenate slag. To solve secondary arsenic contamination, a reduction roasting process was proposed to recover As(0) from calcium arsenate slag. Thermodynamic calculation suggested that reduction pathway Ca3(AsO4)2 → As4(g) is the most feasible, followed by As(s) and As(g). Increasing temperature is conducive to reduction of Ca3(AsO4)2(s) to As4(g). To achieve efficient reduction of Ca3(AsO4)2 and avoid generation of As4O6(g), the temperature should be 650 °C ∼ 952.88 °C and molar ratio of C/Ca3(AsO4)2 should be greater than 3.0. The optimum operating parameters were determined to be C dosage of 14 %, temperature of 900 °C, and reduction time of 2 h, arsenic recovery efficiency and purity of As(0) reached 99.22 % and 99.41 %, respectively. Besides, mechanism of reduction process was elucidated and the findings revealed that reduction process is carried out in steps by Ca3(AsO4)2 → Ca3(AsO3)2 → As4(g) pathway. Moreover, this method has been successfully applied for semi-industrial test, providing an alternative solution for treatment of arsenic-bearing wastes.

Energy analysis of third-octave-mode chatter in tandem cold rolling

Mill chatter has become a complicated issue in the cold tandem rolling process due to the demand for higher rolling speeds and thinner specifications. The third-octave-mode chatter is a prominent vibration form that leads to serious product degradation and equipment damage. This study aims to investigate the energy generation and transmission of the mill-strip system during third-octave-mode chatter using the upper bound method and power flow approach. To obtain the strip forming power, a parabolic cross-section dynamic velocity field is used, which is considered more appropriate for the unsteady rolling process. Additionally, a new linear yield criterion, called the golden section (GS) yield criterion, is established to simplify the integration of internal plastic deformation power. The energy transmission and dissipation in the mill structure are analyzed using a finite element power flow model. The energy distribution variations affected by the rolling speed and time are discussed in detail, and the main cause of vibration intensification is explained. Since the intermediate roll shifting (IRS) has a significant influence on mill stiffness, the energy transfer concerning IRS is also investigated. The results are consistent with previous research. Furthermore, it is concluded that reducing IRS and improving mill stiffness are effective ways to promote mill stability and critical rolling speed.