Pulse density modulation control-based multi-load handling three leg inverter for cooking applications

Purpose Induction heating applications aided by power electronic control have become very attractive in the recent past. For cooking applications, power electronics circuits are very suitable to feed power to multi loads with an appropriate control technique. The purpose of this paper is to develop a three leg inverter to feed power to three loads simultaneously and independently. Design/methodology/approach Pulse density modulation control technique is used to control the output power independently with constant switching frequency. Findings Multi-load handling converter with independent power control is achieved with reduced number of switching devices (two switches/per load) with simple control strategy. Originality/value The proposed system is simulated in MATLAB/Simulink, and the thermal analysis is carried out in COMSOL multi-physics software. The hardware realisation is performed for a 1 kW prototype with 20 kHz switching frequency and 10 kHz pulse density modulation frequency. PIC16F877A microcontroller is used to validate the experimental results for various values of control signals (DPDM). The simulation and experimental results are in good agreement and validates the developed system.

Prediction and Control Model of Musculoskeletal Disorders in the Instant Noodle Company in Makassar 2020–2050

BACKGROUND: There are many risk factors that result in musculoskeletal disorders because of work. This also occurs in the instant food industry, where apart from manual load handling and repetitive work, the production process can also results in risks. AIM: The aims of this study are to predict the musculoskeletal disorders in the next 50 years and the effectiveness of scenarios for controlling musculoskeletal disorders. METHODS: This study employed Research and Development method through a dynamics system approach. This research was conducted in one of the industries that produce instant food in South Sulawesi, Indonesia. The data obtained was based on interviews, which were further analyzed using Interpretative Structural Modeling. RESULTS: Based on the simulation results for 30 years, it was found that there was an increase in the average musculoskeletal disorder incidence by 20.63% per year. At the end of the simulation in 2050, the number of musculoskeletal disorder incidents became 48481.69. In this case, the simulation for 30 years (2020–2050) was conducted on a model of controlling occupational diseases at an instant noodle company in Makassar by providing treatment in the form of reducing risk factors that cause musculoskeletal disorders. Based on the simulation results for 30 years (2020–2050), musculoskeletal disorders have the most significant contribution to the increase of occupational diseases incidents as a whole. The increase in musculoskeletal disorders is an accumulation of several risk factors that exist in the instant noodle production process. CONCLUSIONS: Prediction of the musculoskeletal disorder incidence using a dynamic system approach for 30 years (2020–2050) has increased by an average of 20.63% per year. The behavior of the model after receiving treatment on the occurrence of musculoskeletal disorders has an average decrease in the average incidence of 51.11% per year. In this case, to control the musculoskeletal disorder incidence, the elements or variables controlled simultaneously are work posture, lifting load, and length of work.

Application of Biomechanics Instrumentation in Occupational Health Research

Occupational morbidities during manual material handling operations are routine at workplaces. This is a global burden contributing substantially to the economy. The multifactorial etiology for musculoskeletal disorders (MSDs) along with workplace stressors require multidisciplinary preventive effort. Biomechanics plays a pivotal role in occupational health research quarrying into the root cause analysis of posture, load handling, muscular loading, balance, and stability at work. Sophisticated instrumentation and experimental techniques assist in understanding the biomechanical mechanisms of MSDs and ergonomic principles, etc. Kinetic, kinematic, isotonic, isokinetic, as well as isometric experimental modes investigate body postures and muscular responses. Foundation of biomechanics instrumentation and injury mechanism would aid researchers alongside ergonomists in dealing with identification, assessment, and control of workplace risks through participatory ergonomics approach. Judicious utilization of this discipline would approach a long-term sustainable solution to protect health and safety of workers at the workplace.

Uso de carretilla de acero en transporte de carga para prevención de trastornos musculo-esqueléticos en los trabajadores de despacho de la empresa Ecovasti S.A.

Introduction. Manual lifting and carrying of loads that are equal to or greater than 25 kg are considered high ergonomic risk for causing musculoskeletal disorders in any activity where there is no load sharing or mechanical assistance. Objective. This research applies the use of a steel mask as a mechanical aid to attenuate musculoskeletal disorders in the workers of the company Ecovasti S.A. who lift and move the jars of alcoholic beverages in the delivery of the product to the customers. Methodology. A preliminary analysis of the lifting and moving of loads in the manual dispatch of alcoholic beverage jars was made using Snook and Ciriello tables to find the maximum acceptable weight and the level of ergonomic risk, then the key indicators of pull and push method (KIM PP) was applied to demonstrate the ergonomic improvement by implementing the help of a mobile steel forklift. Results. The preliminary study with the Snook and Ciriello tables indicates a maximum load handling weight for lowering, lifting, transporting and dragging: 11.9 kg; 7.79 kg; 16.43 kg and 25.67 kg respectively, considering male gender, with a protection percentage of 90%, maximum distance traveled of 8 m, load weight of 23 kg per jug of alcoholic beverage, average transfer height of 0.8 m, with a frequency of 15 transfers per hour. The result of the application of the ergonomic improvement with the use of the key indicators of pull and push method (KIM PP) was a value of 1, which corresponds to a low ergonomic risk with a low probability of physical overload. Conclusion. The result of the application of a steel trolley for the manual transport of alcoholic beverage jugs in the dispensing to customers attenuates the level of ergonomic risk to low risk values and could help prevent musculoskeletal disorders.

Evaluation of Physical Risk during Necropsy and Morgue Activities as Risk Management Strategy

Physical risk assessments allow us to understand work-related critical issues, thus representing a useful tool in risk management strategies. In particular, our study focuses on the identification of already known and emerging physical risks related to necropsy and morgue activities, as well as crime scene investigations. The aim of our study is, therefore, to identify objective elements in order to quantify exposure to such risk factors among healthcare professionals and working personnel. For the research of potentially at-risk activities, data from the Morgue of Policlinico Umberto I Hospital in Rome were used. The scientific literature has been reviewed in order to assess the risks associated with morgue activity. Measurements were performed on previously scheduled days, in collaboration with the activities of different research units. The identified areas of risk were: microclimate; exposure to noise and vibrations; postural and biomechanical aspects of necropsy activities. The obtained results make it possible to detect interindividual variability in exposure to many of the aforementioned risk factors. In particular, the assessment of microclimate did not show significant results. On the contrary, exposure to vibrations and biomechanical aspects of load handling have shown potential risk profiles. For this reason, both profiles have been identified as possible action targets for risk management strategies.

Study Of The Influence Of Light Weather On The Mechanical Properties Of Para-Aramid Filaments

The article presents the prospects for the growth of construction volumes in the Republic of Uzbekistan, as a consequence of the need for load-handling devices (LHD) made of synthetic woven belts and ropes (STLK). The results of experimental work are presented, where the wear of textile materials after exposure to light weather is characterized by a change in mechanical properties, which affects the reliability of products during operation.

Guia do oceanógrafo: Manuseio de cabos e acessórios

Oceanography is a multidisciplinary science that deals with the physical, chemical, geological e biological aspects of the marine environment. As most of the sciences, oceanographic research relies heavily on sampling procedures, which can be rather simple, as obtaining a water sample at sea surface, or very complex, as bringing an uncontaminated sediment sample from hadal regions (up to 11,000 m deep) to the surface. Despite the sampling operation complexity, it is of primary importance the use of the adequate instrumentation, as well the expertise of the instrument operator. Ideally, the operator should have a good knowledge of the technical characteristics of the instruments themselves, as well as the correct procedures for their operation. In addition, he should be well acquainted to the ship equipment employed in the deployment, operation and retrieval of those instruments, including cables, winches and cranes. Only if these aspects are taken in account a reliable and safe operation can be attained. In this way, this guide was conceived as a basic reference for researchers in their on-board operations, although certainly being useful for a wide range of outdoor activities. It was based on the authors years of experience in field work onboard research and fishing vessels. It includes notions on nautical cables, onboard load handling equipment and hardware, basic ropework, basic net weaving and repairing and a nautical glossary.

Occupational risk factors for shoulder chronic tendinous pathology in the Spanish automotive manufacturing sector: a case-control study

Background Musculoskeletal Diseases (MSDs) are among the most prevalent health problems encountered in the workforce in Europe. Multiple risk factors contribute to their onset. In the present study, different individual risk factors for chronic tendinous pathology affecting the shoulder were analysed in a sample of workers from the automotive manufacturing sector. Methods An observational retrospective study was conducted with 73 cases of officially recognised and compensated occupational diseases and 94 aleatory cases of healthy workers from the same car assembly company. The experimental group comprised individuals with tendinous chronic pathology of the rotator cuff. Multiple variables that identified the risks present in the job were assessed along with participants clinical evaluation. Furthermore, two standardised guidelines for risk factors assessment were also used: the Spanish National Institute of Social Security (INSS) and the American Occupational Information Network (O*Net). Both descriptive statistical analysis and Odds ratios calculations considering the occupational disease as a dependent variable were performed. Results The use of hand tools, exposure to mechanical pressure in the upper limbs and awkward postures were the most prevalent risk factors. Pressure on the palm of the hand and the hand tool impacting the hand were also important risk factors. Some psychosocial factors such as lack of autonomy and mental workload were also associated shoulder tendinous diseases. The association of age, load handling, and awkward postures were the core risk factors responsible for most of the tendinous chronic injuries of the shoulder in this sample of car assembly workers. Conclusions Both ergonomic and psychosocial factors were present and increased the risk of developing occupational chronic tendinopathies at the shoulder in this sample of workers. Aging, load handling, and awkward postures showed the strongest predictive values. Greater knowledge of how risk factors interact would facilitate the design of better preventive workplace strategies.