Javier López-Martínez

Musculoskeletal disorders: OWAS review

The prevention of musculoskeletal disorders (MSD) is very important in the world. Governments and companies are the most interested. The objective of the present work is to review the literature on the applications of the OWAS method in the diverse sectors or fields of knowledge and countries from its publication to March 2017. The use of OWAS method has been classified by categories of knowledge, by country and by year. The search was made by selecting only the main collection of the Web of Science. This was selected by the option “Advanced search” using the term OWAS (ts=OWAS) for the time period of 1900 to 2017. A total of 166 results were found, consisting of conference papers and articles in scientific journals. In conclusion, the OWAS has been applied mainly in two sectors: “Manufacturing industries” and “Healthcare and Social assistance activities”. This method needs to be complemented with other indirect or direct methods. Also, whenever the OWAS has been used, whether individually or together with other methods, musculoskeletal disorders risks have been detected, this perhaps being an indicator to review the evaluation parameters because overestimating the risk.

Distributed network for measuring climatic parameters in heterogeneous environments: Application in a greenhouse

Abstract In Mediterranean countries of Southern Europe, the climatic conditions are usually favourable to cultivate greenhouse vegetables but not always for workers. The aim of this study was to design a network of weather stations capable of gathering data of environmental parameters related to the wellbeing of workers in greenhouses in south-eastern Spain. The unevenness of the thermal environment was studied both vertically as well as horizontally following guideline ISO 7726. The results indicate that the greenhouse should be considered a heterogeneous environment, implying that, for an evaluation of the environmental conditions related to thermal stress of the workers inside the greenhouse, measurements should be taken at different points within the greenhouse at three heights (ankle, abdomen, and head).

On air temperature distribution and ISO 7726-defined heterogeneity inside a typical greenhouse in Almería

Abstract Studies about the air temperature inside greenhouses are usually focused on the crop growth. However, the thermal environment inside greenhouses can affect the safety of the workers and also their productivity. This work focuses on the study of air temperature conditions with respect to workers following the requirements and methods gathered in ISO 7726, which indicates that measurements should be taken at different points in both, horizontal and vertical directions in order to study heterogeneous thermal environments. For the present work, data were gathered by the Wireless Sensor Network (WSN) designed in our previous work, hereby extended by an experimental campaign carried out during a complete year in a typical greenhouse in Almeriia. The aim is performing a long-term study of air temperature inside a greenhouse as well as the assessment of air temperature heterogeneity. The results, which allow characterizing air temperature inside the greenhouse, prove the existence of patterns of heterogeneity as a function of the incidence of sunlight and time of day. During the analysed period, air temperature heterogeneity is mainly present in the central hours of the day and it is higher in the horizontal dimension rather than vertically. In addition, it has been observed that the vast majority of homogeneous days correlate with cloudy days. Finally, based on the results obtained some recommendations are presented for assessing the thermal environment of greenhouses.

A Low-Cost Modular Platform for Heterogeneous Data Acquisition with Accurate Interchannel Synchronization

Most experimental fields of science and engineering require the use of data acquisition systems (DAQ), devices in charge of sampling and converting electrical signals into digital data and, typically, performing all of the required signal preconditioning. Since commercial DAQ systems are normally focused on specific types of sensors and actuators, systems engineers may need to employ mutually-incompatible hardware from different manufacturers in applications demanding heterogeneous inputs and outputs, such as small-signal analog inputs, differential quadrature rotatory encoders or variable current outputs. A common undesirable side effect of heterogeneous DAQ hardware is the lack of an accurate synchronization between samples captured by each device. To solve such a problem with low-cost hardware, we present a novel modular DAQ architecture comprising a base board and a set of interchangeable modules. Our main design goal is the ability to sample all sources at predictable, fixed sampling frequencies, with a reduced synchronization mismatch (<1 μs) between heterogeneous signal sources. We present experiments in the field of mechanical engineering, illustrating vibration spectrum analyses from piezoelectric accelerometers and, as a novelty in these kinds of experiments, the spectrum of quadrature encoder signals. Part of the design and software will be publicly released online.