118 research outputs found
Improving manual assembly lines devoted to complex electronic devices by applying Lean tools
Manual assembly lines are usually deeply studied before implementation. Nevertheless, several problems upsurge when the product needs to be slightly changed. This is very common in complex electric and electronic devices usually produced in small batches, where the customers are demanding more and more features and the product needs to be continuously updated. However, these updates sometimes create huge difficulties for the previously installed assembly line, generating as well, line unbalancing and wastes of time regarding the initial situation. In this paper, a deep study of an adjusted assembly line of electronic devices was carried out using Value Stream Mapping (VSM) method to fully understand and document the different tasks and operations. The Lean Line Balancing (LLB) was also applied in order to reduce the line bottleneck by balancing the Task Time (TT) of each workstation so that there are no delays, and nobody is overburden with their task. Standardized processes and standardized work were also applied. During the line layout development stage, assembly fixtures, wastes reductions and visual management techniques were applied as well, different concepts were generated and, finally, the best solutions were selected. Throughout the study, many benefits for the studied manual assembly line were found, which can be considered as a strong motivation to apply Lean Manufacturing (LM) tools for better line efficiency and production rate.info:eu-repo/semantics/publishedVersio
The Improvement of an APEX Machine involved in the Tire Manufacturing Process
Over the years, there has been a huge expansion in the automotive component industry and its consequent innovation, which has evolved along with automation and robotics. Therefore, in order to ensure component quality, as well as the quality of the entire production process, it is crucial to enhance competitiveness in the sector. Since quality is a key feature in this industry, all manufacturers and suppliers are scrutinized by systematic audits to ensure constant improvements. This work was developed at a multinational industry and focuses on tire production for the automotive sector. Tires present a complex production process, which covers a wide range of activities from mixing, preparation, construction and vulcanization to the inspection departments, all of which are greatly predisposed to process improvement. In one of these departments (Preparation - APEX machines, responsible for the tire bead production), one of the main problems detected was directly related to a large number of failures in the pneumatic systems. These were found to be difficult to control, both in terms of speed and positioning. Some of the failures in automation were generating delays in certain processes, leading to lengthy setup times and culminating in higher production costs. In order to achieve greater quality, reliability and accuracy, a higher level of automation was applied to these kinds of machines by resorting to 5S methodology. A safety upgrade of the equipment was also undertaken, which will allow for the improvement of workplace safety.The performance improvement of the APEX machines was reached by implementing the following strategies: the automation of conveyor and tray movements between the cutting and application subprocesses; the implementation of 5S methodology; the automation of the cutting process; the updating of safety devices; and the automated control of the separation subprocess. A strong decrease in the breakdown time was recorded (-62%) resulting of the project implementation. The APEXmachine performance was also improved in 9%.info:eu-repo/semantics/publishedVersio
Improving environmental sustainability of agriculture in Egypt through a life-cycle perspective
Soil plays an essential role as a habitat, source of nutrients and support for vegetation. Promoting food security and environmental sustainability of agricultural systems requires an integrated approach to soil fertility management. Agricultural activities should be developed with preventive approaches aimed at avoiding or reducing negative impacts on the soil physicochemical and biological properties and the depletion of soil nutrient reserves. In this regard, Egypt has developed the Sustainable Agricultural Development Strategy to encourage environmentally friendly practices among farmers, such as crop rotation and water management, in addition to extending agriculture to desert areas, favoring the socio-economic development of the region. In order to evaluate the outcomes of the plan beyond quantitative data of production, yield, consumption and emissions, the environmental profile of agriculture in Egypt has been assessed under a life-cycle perspective in order to identify the associated environmental burdens and ultimately contribute to improving the sustainability policies of agricultural activity within the framework of a crop rotation system.
In particular, a two-year crop rotation (Egyptian clover-maize-wheat) was analyzed in two distinct agricultural areas in Egypt: New Lands in desert regions and Old Lands along the Nile River, traditionally recognized as fertile areas due to the river alluvium and water availability. The New Lands had the worst environmental profile for all impact categories, except for Soil organic carbon deficit and Global potential species loss. Irrigation and on-field emissions associated with mineral fertilization were identified as the most critical hotspots of Egyptian agriculture. In addition, land occupation and land transformation were reported as the main drivers of biodiversity loss and soil degradation, respectively. Beyond these results, further research on biodiversity and soil quality indicators is needed to more accurately assess the environmental damage caused by the conversion of deserts into agricultural areas, given the species richness these regions holdThis research is supported by the project Enhancing diversity in Mediterranean cereal farming systems (CerealMed), funded by PRIMA Programme, FEDER/Ministry of Science and Innovation– Spanish National Research Agency (PCI2020-111978); and Academy of Scientific Research and Technology (ASRT); and the project Transition to sustainable agri-food sector bundling life cycle assessment and ecosystem services approaches (ALISE), funded by the Spanish National Research Agency (TED2021-130309B-I00). S.L.O., M.T.M. and S.G.G belong to the Galician Competitive Research Group (GRC ED431C-2021/37) and to the Cross-disciplinary Research in Environmental Technologies (CRETUS Research Center, ED431E 2018/01)This research is supported by the project Enhancing diversity in Mediterranean cereal farming systems (CerealMed), funded by PRIMA Programme, FEDER/Ministry of Science and Innovation– Spanish National Research Agency (PCI2020-111978); and Academy of Scientific Research and Technology (ASRT); and the project Transition to sustainable agri-food sector bundling life cycle assessment and ecosystem services approaches (ALISE), funded by the Spanish National Research Agency (TED2021-130309B-I00). S.L.O., M.T.M. and S.G.G belong to the Galician Competitive Research Group (GRC ED431C-2021/37) and to the Cross-disciplinary Research in Environmental Technologies (CRETUS Research Center, ED431E 2018/01)S
Investigating the effect of previous treatment on wheat biomass over multiple spatial frequencies
In this study we use the maximum overlap discrete packet transform (MODWPT) to investigate residual effects on wheat biomass of fertigation treatments applied to a previous crop. The wheat crop covered nine subplots from a previous experiment on melon response to fertigation. Each subplot had previously received a different level of applied nitrogen. Many factors affect wheat biomass, causing it to vary at different spatial frequencies. We hypothesize that these will include residual effects from fertilizer application (at relatively low spatial frequencies) and the local influence of individual plants from the previous melon crop (at high frequency). To test this hypothesis we use the MODWPT to identify the dominant spatial frequencies of wheat biomass variation, and analyse the relationship to both the previous fertilizer application and the location of individual melon plants in the previous crop. The MODWPT is particularly appropriate for this because it allows us first to identify the key spatial frequencies in the wheat biomass objectively and to analyse them, and their relationship to hypothesized driving factors without any assumptions of uniformity (stationarity) of wheat-biomass variation.
The results showed that the applied nitrogen dominated the wheat biomass response, and that there was a noticeable component of wheat-biomass variation at the spatial frequency that corresponds to the melon cropping. We expected wheat biomass to be negatively correlated with the position of melons in the previous crop, due to uptake of the applied nitrogen. The MODWPT, which allows us to detect changes in correlation between variables at different frequencies, showed that such a relationship was found across part of the experiment but not uniformly
Circular viral DNA detection and junction sequence analysis from PBMC of SHIV-infected cynomolgus monkeys with undetectable virus plasma RNA
AbstractExtrachromosomal forms of human immunodeficiency virus (HIV)-1 can be detected in peripheral blood mononuclear cell (PBMC) from HIV-infected patients in the absence of detectable viral replication and are thought to be a sign of active but cryptic virus replication. No information, however, are available on whether these forms are also present in animal models for acquired immunodeficiency syndrome (AIDS) and on their relation with other methods of detection of virus replication. To this aim, a polymerase chain reaction (PCR) approach was used to detect and analyze unintegrated circular 2-LTR-containing forms in PBMC of simian human immunodeficiency virus (SHIV)89.6P infected cynomolgus monkeys with RNA levels ranging between 1.8 × 106 and less than 50 copies/ml of plasma. 2-LTR forms were detected in 96.5% of monkeys' samples above 50 copies/ml of plasma, whereas they were present in 75.8% of monkeys' samples below 50 copies/ml of plasma. Persistence of unintegrated viral DNA in monkeys with undetectable plasma RNA could indicate either stability in non-dividing cells or ongoing low levels of viral replication in dividing cells
Ultrasonic evidence of an uncorrelated cluster formation temperature in manganites with first-order magnetic transition at T_C
Ultrasonic attenuation and phase velocity measurements have been carried out
in the ferromagnetic perovskites La_{2/3}Ca_{1/3}MnO_3 and
La_{2/3}Sr_{1/3}MnO_3. Data show that the transition at the Curie temperature,
T_C, changes from first- to second-order as Sr replaces Ca in the perovskite.
The compound with first-order transition shows also another transition at a
temperature T* > T_C. We interpret the temperature window T_C < T < T* as a
region of coexistence of a phase separated regime of metallic and insulating
regions, in the line of recent theoretical proposals.Comment: 4 pages, 2 figure
Sodium Intake from Foods Exceeds Recommended Limits in the Spanish Population: The ANIBES Study
Excessive sodium consumption is associated with adverse health effects. An elevated dietary intake of salt (sodium chloride) has been related to high blood pressure or hypertension, a major but modifiable risk factor for cardiovascular disease, as well as to other ill health conditions. In the present work, our aim was to describe the contribution of foods to sodium consumption within the Spanish population in a representative sample from the "anthropometric data, macronutrients and micronutrients intake, practice of physical activity, socioeconomic data and lifestyles in Spain" (ANIBES) study (9-75 years), to identify high consumer groups, as well as the major food groups that contribute to sodium intake in the Spanish diet. Intakes were assessed by 3-day food records collected on a tablet device. Sodium intakes across the ANIBES study population exceeded recommendations, as total intakes reached 2025 ± 805 mg of sodium per day, that is approximately 5.06 g/day of salt (excluding discretionary salt, added at the table or during cooking). Sodium intakes were higher in males than in females and within the youngest groups. Main dietary sources of sodium were meat and meat products (27%), cereals and grains (26%), milk and dairy products (14%) and ready-to-eat meals (13%). Given the established health benefits of dietary salt reduction, it would be advisable to continue and even improve the current national initiatives of awareness and educational campaigns and particularly food reformulation to decrease overall salt intakes across the Spanish population
Sentimento de proteção em relação ao HIV/AIDS: o que dizem estudantes do ensino médio de Manaus (Amazonas, Brasil)
Atitudes de combate e prevenção ao HIV/AIDS não resultam somente de informações e conhecimento científicos sobre o HIV e a AIDS. O objetivo desse estudo foi compreender o sentimento de proteção e/ou vulnerabilidade de estudantes em relação ao HIV/AIDS. Participaram da pesquisa 72 estudantes do Ensino Médio (média de 16,8 anos) de duas escolas de Manaus – AM, que responderam a um questionário. Para este trabalho, foram analisadas apenas duas questões sobre o sentimento de proteção em relação a AIDS. A maioria dos estudantes se sente protegida, porque utilizam métodos de prevenção, usam ou têm intenção de fazer uso do preservativo, acreditam que as informações são suficientes e não convivem com pessoas que possuem a doença. Os que não se sentem protegidos afirmam entre outros, não saber quem possui AIDS e que, há outros meios de transmissão do HIV. O sentimento de proteção ou vulnerabilidade ao HIV/AIDS depende de vários fatores, dentre esses, o conhecimento é importante para a conscientização e atitudes de prevenção contra a HIV/AIDS, mas não é o único e nem o mais importante.Fundos nacionais através da FCT (Fundação para a Ciência e a Tecnologia) no âmbito do projeto do CIEC (Centro de Investigação em Estudos da Criança) da Universidade do Minho, com a referência UID/CED/00317/201
GITR Activation Induces an Opposite Effect on Alloreactive CD4+ and CD8+ T Cells in Graft-Versus-Host Disease
Glucocorticoid-induced tumor necrosis factor receptor family-related gene (GITR) is a member of the tumor necrosis factor receptor (TNFR) family that is expressed at low levels on unstimulated T cells, B cells, and macrophages. Upon activation, CD4+ and CD8+ T cells up-regulate GITR expression, whereas immunoregulatory T cells constitutively express high levels of GITR. Here, we show that GITR may regulate alloreactive responses during graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (BMT). Using a BMT model with major histocompatibility complex class I and class II disparity, we demonstrate that GITR stimulation in vitro and in vivo enhances alloreactive CD8+CD25− T cell proliferation, whereas it decreases alloreactive CD4+CD25− proliferation. Allo-stimulated CD4+CD25− cells show increased apoptosis upon GITR stimulation that is dependent on the Fas–FasL pathway. Recipients of an allograft containing CD8+CD25− donor T cells had increased GVHD morbidity and mortality in the presence of GITR-activating antibody (Ab). Conversely, recipients of an allograft with CD4+CD25− T cells showed a significant decrease in GVHD when treated with a GITR-activating Ab. Our findings indicate that GITR has opposite effects on the regulation of alloreactive CD4+ and CD8+ T cells
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