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Full-Text Articles in Engineering

Hearing Assessment Of Forest Loggers, Antonio A. Fonseca Jan 2009

Hearing Assessment Of Forest Loggers, Antonio A. Fonseca

LSU Master's Theses

Forest logging is the process in which trees are cut down for forest management and/or timber harvest. According to OSHA, logging is the most dangerous occupation in the United States. It consistently represents one of the most hazardous industries, with a fatality rate more than 21 times higher than the rate for all workers in the United States. Yet, little research has been performed to determine the long term effect of noise on forest loggers. OSHA regulations state that the maximum permissible hearing in an 8 hour shift should not exceed 90 dB. Occupational noise exposure is recognized as a …


Assessing The Accuracy Of Task Time Prediction Of An Emerging Human Performance Modeling Software - Cogtool, Oluwakemi Damilola Adio Jan 2009

Assessing The Accuracy Of Task Time Prediction Of An Emerging Human Performance Modeling Software - Cogtool, Oluwakemi Damilola Adio

LSU Master's Theses

There is a need for a human performance modeling tool which not only has the ability to accurately estimate skilled user task time for any interface design, but can be used by modelers with little or no programming knowledge and at a minimal cost. To fulfill this need, this research investigated the accuracy of task time prediction of a modeling tool – CogTool - on two versions of an interface design used extensively in the petrochemical industry – DeltaV. CogTool uses the KeyStroke Level Model (KLM) to calculate and generate time predictions based on specified operators. The data collected from …


Effects Of Physical And Mental Tasks On Heart Rate Variability, Satya Anasuya Paritala Jan 2009

Effects Of Physical And Mental Tasks On Heart Rate Variability, Satya Anasuya Paritala

LSU Master's Theses

Demands at work are associated with an increased risk of cardio vascular diseases, but little is known about its underlying connection. The purpose of this study was to evaluate the effects of physical and mental tasks that induced stress, on Heart Rate Variability (HRV). Another aim was to observe the trends in subjective workload ratings in conjunction with the physiological response of the heart and also to assess the comfort level of the participants while wearing the heart rate monitor and performing tasks. Heart rate was recorded while at rest and while performing the tasks. Subjective workload ratings were obtained …


Laser Assisted Friction Stir Welding: Finite Volume Method And Metaheuristic Optimization, Shivani Daftardar Jan 2009

Laser Assisted Friction Stir Welding: Finite Volume Method And Metaheuristic Optimization, Shivani Daftardar

LSU Master's Theses

Friction Stir Welding (FSW) is a solid state joining process that uses a non-consumable rotating welding tool to generate frictional heat at the welding location. Large forces are required to produce friction between the welding tool and the work piece which increases the wear rate of the welding tool in welding materials with high melting temperature. Several different approaches have been developed to address this problem. This thesis focuses on a new modification of friction stir welding, called Laser Assisted Friction Stir Welding, a process developed in the last decade. This process uses laser energy to preheat the work piece …


Neck Muscles Activity And Upper Body Extremity Angles In Dynamic Overhead Lifting, Mohamed Wassim Mokrani Jan 2009

Neck Muscles Activity And Upper Body Extremity Angles In Dynamic Overhead Lifting, Mohamed Wassim Mokrani

LSU Master's Theses

Injuries of the neck and shoulders are common among workers who perform overhead tasks. In order to develop an injury-free working environment with regards to occupational musculoskeletal stress, it is pivotal to understand the pathophysiology of mechanical stress on the musculoskeletal system. The objective of this research was to study the effect of overhead lifting on the sternocleidomastoid and upper Trapezius muscles. Upper body joint angles were also analyzed using APAS during the overhead lifting. This study was conducted using two devices. The set of equipment incorporates an electromyography device, and the APAS. Two electrodes were placed at the muscle …


Thermomechanical Modeling And Optimization Of Friction Stir Welding, Manthan Malde Jan 2009

Thermomechanical Modeling And Optimization Of Friction Stir Welding, Manthan Malde

LSU Master's Theses

This thesis research implemented an existing thermomechanical model of friction stir welding process, and studied the surrogate model-based optimization approach to obtain optimal process parameters for the modeled friction stir welding process. As an initial step, the thermomechanical model developed by Zhu and Chao for friction stir welding of 304L stainless steel was replicated using ANSYS. The developed model was then used to conduct parametric studies to understand the effect of various input parameters like total rate of heat input, welding speed and clamping location on temperature distribution and residual stress in the workpiece. With the data from the simulated …