Ergonomic Risk Assessment using Postural Analysis Tools in a Bus Body Building Unit

Work-related musculoskeletal disorders (WMSD) which are related with repetitive and demandingworking conditions continue to represent one of the biggest problems throughout the world.Assessment of exposure levels to MSD risk factors can be an appropriate base for planning and implementing interventional ergonomics programs in theworkplace. The presents study is focused on posture analysis of the workers working in a automotive coach manufacturing company (bus body building) company. The study wasconducted on 38 workers engaged in various process of manufacturing. The different activities of the workers were recorded by Video and still photography, and these images were used for analysis. Posture analysis toolsRULA, REBA and QEC were used. The results of RULA showed that about 31.57% of the workers were under high risk level and needed a necessary action immediately. About 28.95% of the workers were under medium risk levels andabout 28.95% of the workers were at lower risk levels. The results of REBA showed that about26.32% of the workers wereunder very high risk levels and required immediate change. About 23.68% of the workers were at high risk levels and a change is necessary soon, and 42.10% of the workers were at medium risk levels. According to the QEC method of assessment, it was found that 10.53% of the workers needed no corrective measures. About 31.58% of the workers needed further investigation and 34.21% of the workers were at high risk and required immediate change. It can be  concluded that  there are ergonomic deficiencies in the planning and work methods.  A significant proportion of the workers are working inhigh risk postures. Thus the workers are under moderate to high risk of Work-related Musculoskeletal disorders (WMSDs). The study recommended a proper implementation of ergonomics interventions program with awareness and training among workers to reduce the risksof WMSD. Keywords: Posture analysis, WMSD, bus body building

Performance, emission and combustion characteristics of a semi-adiabatic diesel engine using cotton seed and neem kernel oil methyl esters

AbstractThe performance, emission and combustion characteristics of a diesel engine are investigated using two methyl esters: One obtained from cotton seed oil and other from neem kernel oil. These two oils are transesterified using methanol and alkaline catalyst to produce the cotton seed oil methyl ester (CSOME) and neem kernel oil methyl ester (NKOME) respectively. These biodiesels are used as alternative fuels in low heat rejection engine (LHR), in which the combustion chamber temperature is increased by thermal barrier coating on piston face. Experimental investigations are conducted with CSOME and NKOME in a single cylinder, four stroke, direct injection LHR engine. It is found that, at peak load the brake thermal efficiency is lower by 5.91% and 7.07% and BSFC is higher by 28.57% and 10.71% for CSOME and NKOME in LHR engine, respectively when compared with conventional diesel fuel used in normal engine. It is also seen that there is an increase in NOx emission in LHR engine along with slight increase in CO, smoke and HC emissions. From the combustion characteristics, it is found that the values of cylinder pressure for CSOME and NKOME in LHR engine are near to the diesel fuel in normal engine

On the impact of covariance functions in multi-objective Bayesian optimization for engineering design

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordMulti-objective Bayesian optimization (BO) is a highly useful class of methods that can effectively solve computationally expensive engineering design optimization problems with multiple objectives. However, the impact of covariance function, which is an important part of multi-objective BO, is rarely studied in the context of engineering optimization. We aim to shed light on this issue by performing numerical experiments on engineering design optimization problems, primarily low-fidelity problems so that we are able to statistically evaluate the performance of BO methods with various covariance functions. In this paper, we performed the study using a set of subsonic airfoil optimization cases as benchmark problems. Expected hypervolume improvement was used as the acquisition function to enrich the experimental design. Results show that the choice of the covariance function give a notable impact on the performance of multi-objective BO. In this regard, Kriging models with Matern-3/2 is the most robust method in terms of the diversity and convergence to the Pareto front that can handle problems with various complexities.Natural Environment Research Council (NERC

Multi-objective optimization using Deep Gaussian Processes: Application to Aerospace Vehicle Design

International audienceThis paper is focused on the problem of constrained multi-objective design optimization of aerospace vehicles. The design of such vehicles often involves disciplinary legacy models considered as black-box and computationally expensive simulations characterized by a possible non-stationary behavior (an abrupt change in the response or a different smoothness along the design space). The expensive cost of an exact function evaluation makes the use of classical evolutionary multi-objective algorithms not tractable. While Bayesian Optimization based on Gaussian Process regression can handle the expensive cost of the evaluations, the non-stationary behavior of the functions can make it inefficient. A recent approach consisting of coupling Bayesian Optimization with Deep Gaussian Processes showed promising results for single-objective non-stationary problems. This paper presents an extension of this approach to the multi-objective context. The efficiency of the proposed approach is assessed with respect to classical optimization methods on an analytical test-case and on an aerospace design problem

Repeatability of Corticospinal and Spinal Measures during Lengthening and Shortening Contractions in the Human Tibialis Anterior Muscle

Elements of the human central nervous system (CNS) constantly oscillate. In addition, there are also methodological factors and changes in muscle mechanics during dynamic muscle contractions that threaten the stability and consistency of transcranial magnetic stimulation (TMS) and perpherial nerve stimulation (PNS) measures

ERGONOMIC EVALUATION OF LOW COST ADJUSTABLE WORKSTATION FOR ASSEMBLY OPERATION

Ergonomics is the science and technology of fitting the activities and environment to the abilities, dimensions, and needs of people to improve performance while enhancing comfort, health and safety [1] The objective of the present study was to investigate the effects of an ergonomically designed adjustable workstation for performing a repetitive industrial assembly task on operator performance and productivity. Ergonomically designed fully adjustable assembly workstations could be expensive for companies to adopt, especially the small scale industries. Therefore, a low-cost, ergonomically designed adjustable assembly workstation was designed, developed and evaluated for assembly of a product in a manufacturing company. Experiments were conducted on the existing fixed height and on the newly designed ergonomic assembly workstation using five industrial assembly operators. The operator performance on the ergonomically designed workstation was 29% higher compared to the existing non ergonomically designed fixed height assembly workstation. The increased performance was due to flexibility and ergonomic design features incorporated in the workstation

Dental Ergonomics to Combat Musculoskeletal Disorders: A Review

Musculoskeletal disorders (MSDs) are significant workplace problems affecting occupational health, productivity and the careers of dental professionals. The prevalence of MSDs is on the rise for all types of dental workers. In spite of different patterns of work culture, there are parallel levels of symptoms in dentists across nations. Risk factors for MSDs are multifactorial. Symptoms appear very early in careers, with higher prevalence of MSDs even during educational training. Ergonomics improvements, health promotion and organizational interventions are necessary to reduce the risk. An interdisciplinary approach with progressive efforts should be taken to address MSDs in dental professionals

Occurrence of oxytetracycline residues in milk samples from Palakkad, Kerala, India

Background and Aim: Food of animal origin such as milk is vital for nutritional security and should be free of any antibiotic residues due to its public health significance. We designed a study aiming to determine the occurrence of antibiotic residues and in further levels of oxytetracycline residues in pooled raw milk samples from Palakkad district, Kerala. Materials and Methods: We collected pooled raw milk samples were collected from Alathur, Chittoor, and Palakkad blocks of Palakkad district, Kerala. A total of 215 samples were screened for antibiotic residues by microbial inhibition assay (MIA) and the positive samples were subjected to enzyme-linked immunosorbent assay (ELISA) to determine oxytetracycline residues, this was further confirmed using high-performance liquid chromatography (HPLC). Results: We found that out of the 215 pooled raw milk samples screened for antibiotic residues using MIA, 22 samples (10.23%) were positive for antibiotic residues from Palakkad, Kerala. Out of these 22 samples, five (2.33%) were positive for oxytetracycline residues. We further calculated the mean concentration of oxytetracycline residues in these five samples and estimated it to be 201.00±41.25 ng/mL and 272.11±53.21 ng/mL using ELISA and HPLC, respectively. On analyzing these five samples, we found that four samples (1.86%) exceeded the maximum residue limits level of 100 ng/mL for oxytetracycline residues in milk as specified by Codex Alimentarius Commission/Food Safety and Standards Authority of India (FSSAI). Conclusion: This study revealed that the occurrence of oxytetracycline residues in pooled raw milk samples in the Palakkad district of Kerala. Hence, there is a need for surveillance and monitoring of antibiotic residues in milk due to its impact on public health to ensure consumer safety