BACKGROUND: Manufacturing industry workers who repair computers may be exposed to ergonomic risk factors. OBJECTIVES: This project analyzes the tasks involved in the computer repair process to (1) find the risk level for musculoskeletal disorders (MS

Usually, agricultural tractor investments are assessed using traditional economic techniques that only involve financial attributes, resulting in reductionist evaluations. However, tractors have qualitative and quantitative attributes that must be simultaneously integrated into the evaluation process. This article reports a hybrid and multi-attribute approach to assessing a set of agricultural tractors based on AHP-TOPSIS. To identify the attributes in the model, a survey including eighteen attributes was given to agricultural machinery salesmen and farmers for determining their importance. The list of attributes was presented to a decision group for a case of study, and their importance was estimated using AHP and integrated into the TOPSIS technique. In this case, one tractor was selected from a set of six alternatives, integrating six attributes in the model: initial cost, annual maintenance cost, liters of diesel per hour, safety of the operator, maintainability and after-sale customer service offered by the supplier. Based on the results obtained, the model can be considered easy to apply and to have good acceptance among farmers and salesmen, as there are no special software requirements for the application.

Operators of machinery classified as Advanced Manufacturing Technology (AMT) are exposed to high levels of workload and fatigue. However, only few studies have been conducted on this topic in Hispanic-American countries workers. Several instruments be used to assess workload and fatigue; however, only few of them have been adapted to Spanish language. This paper reports on the development and validity testing of a survey instrument in Spanish, aiming to subjectively assess workload and fatigue among AMT operators in Mexico. Method: After an exhaustive literature review in search of already available measurement instruments, they were adapted for content and later translated into Spanish; a pilot test was conducted to evaluate validity and reliability; afterwards appropriate modifications were made to the testing instruments. Final version of the instrument was applied to a group of 121 operators of CNC lathes. Reliability was analyzed using KMO and Cronbach alpha indices. Results: For the assessment of workload, both NASA-TLX and ISTAS 21 methods were incorporated to the survey instrument. As for fatigue assessment tools, these were SOFI-S, FAS and OFER questionnaires. Results show KMO value and Cronbach alpha above 0.6.Conclusions. The survey instrument as designed, allows the collection of reliable and valid data regarding workload and fatigue among AMT operators in Mexico.

OCCUPATIONAL APPLICATIONS Several manufacturing concerns in Mexico, as part of a broader effort to incorporate advanced manufacturing technology, have replaced traditional machines with those using computerized numerical control. As a result, workers have experienced new levels of workload and fatigue levels that have not been previously investigated in depth. Among a sample of over 400 computerized numerical control workers in Mexico, we found that workload has an important effect on the perception of fatigue. Our results also suggest that sleep hours per night, handled weight, and stature of the workers are variables that must be considered in the design of tasks wherein computerized numerical control lathes are present. These results can be useful for managers and industrial engineers to develop and improve production schedules when computerized numerical control machines are operated. TECHNICAL ABSTRACT Background: With the introduction of new and more sophisticated machinery—commonly classified as advanced manufacturing technology—industrial workers must increasingly perform both physical and mental efforts, often simultaneously. A typical case is the operation of computerized numerical control lathes. This type of work has not been thoroughly studied, particularly in developing countries. In these countries, high workload levels are frequently neglected and the extent of fatigue experienced by operators remains unknown and unaddressed. Purpose: We aimed to assess workload, fatigue, and work-related musculoskeletal consequences; to explore the relationship between workload and fatigue; and to identify differences in workload and fatigue levels related to demographic and work-related variables, among computerized numerical control lathe operators in Mexico. Methods: A cross-sectional, descriptive study was completed, using a survey. Workload was assessed using the NASA Task Load Index. Fatigue was assessed using the Swedish Occupational Fatigue Inventory and the Occupational Fatigue Exhaustion Recovery scales. We examined differences in workload and fatigue items/dimensions related to work and demographic variables, as well as correlations between workload, fatigue, and musculoskeletal discomfort. Results: Survey results had generally high internal consistency and sample adequacy. Workload items with the highest scores were overall effort, mental demands, and physical demands. Fatigue dimensions with the highest scores were lack of energy and physical effort. Chronic fatigue was the fatigue state with the highest score. Significant, positive correlations were found among workload items, dimensions/states of fatigue, and musculoskeletal discomfort. Handled weight and sleeping hours were the factors with significant differences across physical demands, physical effort, physical discomfort, lack of motivation, sleepiness, and chronic fatigue. Conclusions: Factors both directly (e.g., handled weight and sleep hours per night) and indirectly (e.g., demographics) related to workload can contribute to perceived fatigue among computerized numerical control lathe operators. Such results may help in developing effective future interventions.

The aim of this job is to propose a procedure that helps ergonomists and engineers to develop task analysis and evaluations in workstations. In the ergonomics field, task analysis is a method to describe and analyze the task performance when users interact with complex systems, this is the first step to do an ergonomic evaluation. Most of the areas in ergonomics requires task analysis, literature contains clear descriptions for task analysis for cognitive tasks, and nevertheless there is a lack of information for biomechanics and design evaluations. In here, a procedure is proposed in order to offer tools to correctly conduct ergonomic assessments that help ergonomists to develop this evaluations and indicate the risk level of certain workstation. This research contains a proposed procedure for task analysis and two case studies applying this procedure. The proposed procedure consists in five phases: recognition, video recording, subtasks separation, video analysis, and frame classification. The proposed procedure is applied in two case studies. The first case study is in a workstation of an automobile parts industry. The second case study is in a shoe manufacturing workstation. Subtasks are identified and classified with frequencies in both jobs, indicating what subtasks are more repetitive, and thus need to be assessed. This work provides a procedure that allows to standardize the process of task analysis in biomechanics and design evaluations, this procedure allows to obtain the frequency of the subtasks that are part of the assessed workstation, and thus it is easier to identify which one of these need to be evaluated with ergonomic methods.

Companies seek to stand out from their competitors and react to other competitive threats. Making a difference means doing things differently in order to create a product that other companies cannot provide. This can be achieved through an innovation process. This article analyses, by means of a structural equation model, the current situation of Mexican maquiladora companies, which face the constant challenge of product innovation. The model associates three success factors for new product development (product, organization, and production process characteristics as independent latent variables) with benefits gained by customers and companies (dependent latent variables). Results show that, in the Mexican maquiladora sector, organizational characteristics and production processes characteristics explain only 31% of the variability (R² = 0.31), and it seems necessary to integrate other aspects. The relationship between customer benefits and company benefits explains 58% of the variability, the largest proportion in the model (R² = 0.58).