Assessing ergonomic risk factors using combined data envelopment analysis and conventional methods for an auto parts manufacturer.

BACKGROUND: Occupational injuries are currently a major contributor to job loss around the world and are also costly for businesses. The absence of rational analysis is felt in this area, so mathematical analysis is needed to obtain the logical results of these injuries in order to find gaps or loss points of the industry. OBJECTIVE: This paper assesses the effects of five demographic factors on ergonomic risk and occupational injuries using an integrated mathematical programming approach. The obtained results will help managers to carry out any required corrective actions or establish benchmarks. METHODS: Two typical ergonomic risk assessment methods, the Quick Exposure Check (QEC) and Rapid Entire Body Assessment (REBA), are applied to assess musculoskeletal disorders in workers. Then, considering the five demographic factors as input variables and risks computed by the QEC and REBA methods as outputs, final risk rates for each decision-making unit (DMU) are calculated using data envelopment analysis (DEA). The importance and weight of each risk factor is analyzed using statistical techniques and analysis of variance (ANOVA). To demonstrate the applicability of the methodology, it is applied to a large auto parts manufacturer. RESULTS: The results revealed that the information obtained by DEA is consistent with those for REBA and QEC, which shows that education, experience and weight are factors that could help reduce ergonomic risks. CONCLUSION: It is shown that demographic variables such as age, height, weight, education and work experience play an important and effective role in the explanation of ergonomic risk factors.

Evaluation of Bacterial Contamination on Prehospital Ambulances Before and After Disinfection.

BACKGROUND: The contamination of the environment, ambulance equipment, and staff hands consequently are major factors which create nosocomial infections in emergency patients. The contamination of equipment and devices plays an important role in nosocomial infections. OBJECTIVES: The aim of this study was to determine the effectiveness of a disinfectant on the rate of microbial contamination of ambulances in Qom Emergency Medical Services (EMS), Qom, Iran. METHODS: This is a quasi-experimental study with a before-after design in order to determine microbial contaminations at the rear and front cabin of ambulances, as well as medical equipment being utilized in Qom EMS. Saya sept-HP-2% solution was used for disinfection. Bacteriological standard methods were used to identify the contaminations. RESULTS: The contamination rates before and after use of disinfection solution were 52% and eight percent, respectively. Coagulase-negative staphylococci were the most commonly isolated bacterial agent from the equipment (53%). In all equipment, the contamination level has shown a significant reduction after applying disinfectant. CONCLUSIONS: In spite of the fact that the rate of infection from ambulance equipment is high, the results showed that the use of the suitable disinfectant had an effective role in the reduction of bacteria. FarhadlooR, Goodarzi FarJ, AzadehMR, ShamsS, Parvaresh-MasoudM. Evaluation of bacterial contamination on prehospital ambulances before and after disinfection. Prehosp Disaster Med. 2018;33(6):602-606.

Theoretical and experimental investigation of continuous-wave laser scribing on metal thin film: effect of power.

In this paper, the scribing of the metal thin film using a continuous-wave laser is investigated theoretically and experimentally. We propose a reversible relation between incident fluence and ablation width. Microscopic analysis of the results is compared to theoretical expectations. Scribing has been done by focusing a 450 nm laser diode beam on 100 nm chromium thin film. Beam power and scanning speed are varied in the domains of 0.02-1.0 W and 0.05-5 mm/s, respectively. The microscopic images of the thin film show that the average ablation width on metal thin film varies slightly by increasing the scanning speed, which was anticipated by theory. Moreover if scanning speed increases, the ablation quality is reduced significantly and is not compensated by increasing incident power. According to microscopic images of the sample, this method could be a good substitute for pulsed-laser scribing in many applications such as making solar cells.

Smart pixel optical sensor based on positive optical feedback.

A smart pixel optical sensor based on positive optical feedback is described and demonstrated. The scheme uses the reflectance of an external scene as part of the positive feedback loop and uses the nonlinear characteristics of a vertical-cavity surface-emitting laser to obtain bistability and hysteresis. As a result, the continuous reflectance variation of the scene is mapped to a digital output with increased noise immunity for each pixel of the array.