The influence of task design on upper limb muscles fatigue during low-load repetitive work: A systematic review

Ergonomic interventions such as increased scheduled breaks or job rotation have been proposed to reduce upper limb muscle fatigue in repetitive low-load work. This review was performed to summarize and analyze the studies investigating the effect of job rotation and work-rest schemes, as well as, work pace, cycle time and duty cycle, on upper limb muscle fatigue. The effects of these work organization factors on subjective fatigue or discomfort were also analyzed. This review was based on relevant articles published in PubMed, Scopus and Web of Science. The studies included in this review were performed in humans and assessed muscle fatigue in upper limbs. 14 articles were included in the systematic review. Few studies were performed in a real work environment and the most common methods used to assess muscle fatigue were surface electromyography (EMG). No consistent results were found related to the effects of job rotation on muscle activity and subjective measurements of fatigue. Rest breaks had some positive effects, particularly in perceived discomfort. The increase in work pace reveals a higher muscular load in specific muscles. The duration of experiments and characteristics of participants appear to be the factors that most have influenced the results. Future research should be focused on the improvement of the experimental protocols and instrumentation, in order to the outcomes represent adequately the actual working conditions. Relevance to industry: Introducing more physical workload variation in low-load repetitive work is considered an effective ergonomic intervention against muscle fatigue and musculoskeletal disorders in industry. Results will be useful to identify the need of future research, which will eventually lead to the adoption of best industrial work practices according to the workers capabilities

Relação entre a contração e o teor de umidade em madeira de Pinus elliottii, em vários ângulos de grã.

Two species of Pines (Pinus elliottii and Pinus teada) were utilized for the present study. Regression equations were ajusted in function of moisture content and shrinkage values in theree different grain angles (30º, 45º and 90º). High correlation coefficients were found between shrinkage and moisture content from P. S. F. to 0% on the different grain angles. The adjusted equations can be used for the estimatimation of shrinkage (radial e tangential) for similar situations.Duas espécies de Pinus (Pinus elliottii e Pinus taeda) foram utilizadas para realizar o presente estudo. Procurou-se correlacionar através de uma equação de regressão linear, o teor de umidade e a concentração da madeira, considerando três ângulos de grã (30º, 45º e 90º). Existe para as duas espécies uma alta correlação entre a concentração e o teor de umidade da madeira, entre o P.S.F. e o O% de umidade, para os diferentes ângulos estudados. As equações de regressão linear encontradas para ambas espécies, podem ser usadas sem maiores erros de cálculos para a determinação da contração da madeira a diferentes teores de umidade

Autonomous RPCs for a Cosmic Ray ground array

We report on the behaviour of Resistive Plate Chambers (RPC) developed for muon detection in ultra-high energy cosmic ray (UHECR) experiments. The RPCs were developed for the MARTA project and were tested on field conditions. These RPCs cover an area of $1.5 \times 1.2\,{m^2}$ and are instrumented with 64 pickup electrodes providing a segmentation better than $20\,$cm. By shielding the detector units with enough slant mass to absorb the electromagnetic component in the air showers, a clean measurement of the muon content is allowed, a concept to be implemented in a next generation of UHECR experiments. The operation of a ground array detector poses challenging demands, as the RPC must operate remotely under extreme environmental conditions, with limited budgets for power and minimal maintenance. The RPC, DAQ, High Voltage and monitoring systems are enclosed in an aluminium-sealed case, providing a compact and robust unit suited for outdoor environments, which can be easily deployed and connected. The RPCs developed at LIP-Coimbra are able to operate using a very low gas flux, which allows running them for few years with a small gas reservoir. Several prototypes have already been built and tested both in the laboratory and outdoors. We report on the most recent tests done in the field that show that the developed RPCs have operated in a stable way for more than 2 years in field conditions.Comment: To appear in the proceedings of the 35th International Cosmic Ray Conference (ICRC2017), Busan, South Korea. Presented by R. Concei\c{c}\~{a}o. 8 page

Economical Feasibility of Strawberry Production in a Semi-Hydroponic System and Agroindustry of Jelly on a Small Property

Growing strawberries is a great alternative for family farms, it is possible to obtain a good financial return on a small property. Consumption growth Strawberry "in natura" in recent years, along with a high price increase, further assists in the marketing of the fruit. This study aimed to establish a greenhouse to grow plants behave 18,000 Camarosa, with approximate production of 200 kg of strawberries daily in peak harvest in semi-hydroponic system in a family owned, located in the municipality of Canguçu-RS. The strawberry produced should be packaged for sale "in natura" and received in the form of jelly. Strawberries are classified by their diameter (25mm and 15mm) and defects in three classes: Class A, includes all healthy and greater than 25 mm diameter strawberries; class B, includes all the healthy strawberries and with a diameter between 25 mm and 15 mm and the class C, includes all strawberries with less than 15mm diameter. The strawberries in Classes A and B will be sold as "in natura" and Class C will be used for the production of jam. To perform the economic analysis, initially used the SWOT matrix, which is a tool used to perform environmental analysis, as the basis of management and strategic planning. The financial analysis of the project was carried out through the following indications: NPV (Net Present Value), IRR (Internal Rate of Return) and payback. Through the completion of the procedures for determining the cash flow and economic indicators, it was found through studies of scenarios, keeping the price constant and equal to jam £ 5.50, the minimum price of the strawberry "in natura" is worth $ 6.83. The production of jelly is an alternative to adding value to the product and also provides more time for marketing

Autonomous RPCs for a Cosmic Ray ground array

We report on the behaviour of Resistive Plate Chambers (RPC) developed for muon detection in ultra-high energy cosmic ray (UHECR) experiments. The RPCs were developed for the MARTA project and were tested on field conditions. These RPCs cover an area of $1.5 \times 1.2\,{m^2}$ and are instrumented with 64 pickup electrodes providing a segmentation better than $20\,$cm. By shielding the detector units with enough slant mass to absorb the electromagnetic component in the air showers, a clean measurement of the muon content is allowed, a concept to be implemented in a next generation of UHECR experiments. The operation of a ground array detector poses challenging demands, as the RPC must operate remotely under extreme environmental conditions, with limited budgets for power and minimal maintenance. The RPC, DAQ, High Voltage and monitoring systems are enclosed in an aluminium-sealed case, providing a compact and robust unit suited for outdoor environments, which can be easily deployed and connected. The RPCs developed at LIP-Coimbra are able to operate using a very low gas flux, which allows running them for few years with a small gas reservoir. Several prototypes have already been built and tested both in the laboratory and outdoors. We report on the most recent tests done in the field that show that the developed RPCs have operated in a stable way for more than 2 years in field conditions.Peer Reviewe

Régimen térmico y variabilidad espacial de la capa activa en Isla Decepcion, Antártida

El programa de monitoreo de capa activa (CALM) fue desarrollado en las últimas décadas con la finalidad de comprender el impacto del cambio climático sobre los ambientes con permafrost. Este trabajo analiza los resultados obtenidos, en los últimos seis años, de los sitios CALM-S Irizar, Cráter Lake y Refugio Chileno, ubicados en Isla Decepción. En ellos se ha medido el espesor, el estado térmico y la distribución espacial de la capa activa. En los sitios Irizar y Refugio Chileno la evolución del espesor de capa activa varió interanualmente sin una clara tendencia dentro del corto período analizado; por el contrario, el sitio Cráter Lake evidenció una tendencia a la disminución de espesor. La distribución espacial como el espesor de dicha capa en los tres sitios de monitoreo, mostraron estar condicionados principalmente por la potencia de la cubierta de nieve, la litología y la exposición a los vientos. El relieve, la topografía de detalle, la orientación de las laderas frente a la radiación solar incidente, ejercieron un control menor sobre esta distribución. El estado térmico de la capa activa evidenció el control ejercido sobre ella de la temperatura del aire y de la cubierta nival. Así bajo reducidos espesores de nieve, el modelo de penetración en profundidad de la isoterma de 0 ºC, ha permitido aproximar satisfactoriamente el espesor de capa activa.Thermal regime and spatial variability of the active layer in Deception Island, Antarctica The Circumpolar Active Layer Monitoring (CALM) program developed over the last two decades has a leading edge in comprehensive efforts to study the impacts of climate change in permafrost environments. This paper describes results obtained during the last six years, on the active layer thickness, thermal regime and spatial patterns of thaw, at the CALM-S Irizar, Crater Lake and Refugio Chileno sites in Deception Island. In Irizar and Refugio Chileno CALM-S sites the active layer depth varied interannually without any clear trend over the short record available. By contrast, Crater Lake CALM-S showed a slight thinning trend. In all sites, the spatial patterns of thaw and active layer thickness were mainly controlled by snow cover conditions, lithology and the effect of aspect on wind. The relief, the detailed topography and the effect of aspect on solar radiation also exert a local control over its patterns. Air temperature and snow cover controlled the thermal state of active layer. In absence of snow, the use of depth penetration model of the 0 ºC isotherm allowed approximated satisfactorily active layer thickness.info:eu-repo/semantics/publishedVersio

Prototype of an affordable pressure-controlled emergency mechanical ventilator for COVID-19

We present a viable prototype of a simple mechanical ventilator intended as a last resort to ventilate COVID-19 patients. The prototype implements the pressure-controlled continuous mandatory ventilation mode (PC-CMV) with settable breathing rates, inspiration/expiration time ratios and FiO2 modulation. Although safe, the design aims to minimize the use of technical components and those used are common in industry, so its construction may be possible in times of logistical shortage or disruption or in areas with reduced access to technical materials and at a moderate cost, affordable to lower income countries. Most of the device can be manufactured by modest technical means and construction plans are provided.Comment: This version differs from version 2 in that it includes toxicological and bio-safety tests and updated electronic

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO