Simulation of the Attrition of Recycled Concrete Aggregates during Concrete Mixing

Concrete mixing can lead to mechanical degradation of aggregates, particularly when dealing with recycled concrete aggregates. In this work, the attrition of such materials during mixing is studied by means of experiments and simulations. The effect of the presence of fines, water addition, flow configuration of the mixer (co- or counter-current) and impeller frequency is discussed. Experiments were performed in a laboratory Eirich mixer. Discrete element numerical simulations (DEM) were performed on the same geometry by mimicking the behaviour of the material and, in particular, the cohesion induced by water and the cement paste using either Hertz–Mindlin or Hertz–Mindlin with Johnson–Kendall–Roberts (JKR) contact laws. The combination of the collision energy spectra extracted from the DEM simulations and an attrition model allowed the prediction of the mass loss due to attrition in 1-min experiments. Semi-quantitative agreement was observed between experiments and simulations, with a mean relative error of 26.4%. These showed that higher mass losses resulted from operation at the highest impeller speeds, co-current operation, and also with the wet aggregate. Mixing of the agglomerate in the concrete mix resulted in a significant reduction in attrition when compared to mixing aggregates alone. With further validation, the proposed simulation approach can become a valuable tool in the optimization of mixing by allowing the effects of material, machine and process variables to be studied on the mass loss due to attritionThis research was partially funded by the Brazilian Research Agency CNPq (grant number 310293/2017-0)

Physical evaluation on tomatoes cv. 'Romana' during postharvest handling

Tomato postharvest losses are very high in Brazil and the goal of this research was to evaluate the effect of handling and the transport of tomato fruits, cultivar Romana on the steps of harvesting, weight and transportation to the packinghouse, pointing some critical points. Tomatoes were harvested at plastic boxes, weighted and shipped to a packinghouse. Fruits taken directly from the plant were determined as reference. The parameters evaluated were weight loss and mechanical injury and tomato physical quality after storage during 21 days. It was observed an increasing on the weight loss, external damage, and postharvest losses, after storage. Handling and transportation were the cause of an increase in 6.6% in external damage and 1.93% of weight loss after storage, when comparing harvested fruits and fruits evaluated on the packing-house. The main reason for postharvest losses was due to mechanical injury caused during transportation mainly due to the compressure force among fruits and against the plastic boxes.As perdas na pós-colheita para tomate de mesa são altas, e esta pesquisa teve como objetivo quantificá-las, avaliando-se o efeito do manuseio e transporte na qualidade física dos frutos, cultivar Romana, nas etapas de colheita, pesagem e transporte para o galpão de beneficiamento. Tomates foram colhidos em caixas plásticas de colheita, transportados para um ponto de pesagem e, em seguida, enviados para um galpão de beneficiamento e classificação. Utilizaram-se como testemunha frutos retirados diretamente da planta. Os parâmetros observados foram: perda de peso e incidência de danos físicos originados em cada etapa, avaliando-se a aparência externa dos frutos após armazenamento por 21 dias. Observou-se aumento progressivo na perda de peso e incidência de danos físicos, bem como nas perdas pós-colheita após armazenamento. Comparando-se frutos avaliados na colheita e amostrados no galpão de beneficiamento, notou-se que o manuseio e o transporte foram responsáveis por aumento de 6,6% na incidência de danos físicos e 1,93% na perda de peso após armazenamento. As maiores percentagens de frutos descartados foram observadas durante o transporte em caixas plásticas, devido a danos físicos superficiais causados, principalmente, pela compressão de um fruto no outro.321327Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Physical and Physiological Predictors of FRAN CrossFit® WOD Athlete’s Performance

CrossFit® training is one of the fastest-growing fitness activities in the world due to its varied functional movement and competition experience. The performance is present in almost every workout of the day (WOD); however, there is a lack of knowledge in the science that did not allow us to fully understand the performance determinants of CrossFit WOD’s like we do for other individual or team sports. The purpose of this study was to analyze the physical and physiological variables of recreational trained CrossFit athletes during one of the most famous WOD, FRAN, and to identify which variables best determine performance. Methods: Fifteen CrossFit practitioners performed, alone on separate days, 1RM and a maximum of repetitions of pull-ups test, 1RM and a maximum of repetitions of thrusters with 95 lb/43.2 kg, FRAN CrossFit WOD, and 2K Row test. Results: Blood lactate concentrate, HRmax, HRav, and RPE achieved higher values for 2K Row and maximum repetitions of thrusters. Maximum repetition of thrusters and pull-ups, 1RM of thrusters, and 2K Row resulted in moderate to strong correlation with FRAN performance (r = −0.78; r = −0.58; r = −0.67; r = 0.63, respectively). Conclusions and practical applications: FRAN performance was stroninfo:eu-repo/semantics/publishedVersio

O uso de objetos e filmagem no tratamento psicanalítico em grupo de crianças autistas

Este artigo visa apresentar os resultados de uma pesquisa sobre o uso de objetos no tratamento psicanalítico do autismo, que envolveu a realização de um atendimento em grupo de crianças com diagnóstico de Transtorno do Espectro Autista em uma instituição pública de saúde mental. O registro audiovisual dos atendimentos mostrou-se um componente indispensável desta abordagem, em especial nas reuniões com os pais e nas supervisões, convidando a uma reflexão acerca de seu estatuto. A questão da constituição subjetiva e o problema do diagnóstico na infância permearam as discussões aqui propostas

Dissecting central post-stroke pain:a controlled symptom-psychophysical characterization

Central post-stroke pain affects up to 12% of stroke survivors and is notoriously refractory to treatment. However, stroke patients often suffer from other types of pain of non-neuropathic nature (musculoskeletal, inflammatory, complex regional) and no head-to-head comparison of their respective clinical and somatosensory profiles has been performed so far. We compared 39 patients with definite central neuropathic post-stroke pain with two matched control groups: 32 patients with exclusively non-neuropathic pain developed after stroke and 31 stroke patients not complaining of pain. Patients underwent deep phenotyping via a comprehensive assessment including clinical exam, questionnaires and quantitative sensory testing to dissect central post-stroke pain from chronic pain in general and stroke. While central post-stroke pain was mostly located in the face and limbs, non-neuropathic pain was predominantly axial and located in neck, shoulders and knees (P < 0.05). Neuropathic Pain Symptom Inventory clusters burning (82.1%, n = 32, P < 0.001), tingling (66.7%, n = 26, P < 0.001) and evoked by cold (64.1%, n = 25, P < 0.001) occurred more frequently in central post-stroke pain. Hyperpathia, thermal and mechanical allodynia also occurred more commonly in this group (P < 0.001), which also presented higher levels of deafferentation (P < 0.012) with more asymmetric cold and warm detection thresholds compared with controls. In particular, cold hypoesthesia (considered when the threshold of the affected side was <41% of the contralateral threshold) odds ratio (OR) was 12 (95% CI: 3.8–41.6) for neuropathic pain. Additionally, cold detection threshold/warm detection threshold ratio correlated with the presence of neuropathic pain (ρ = −0.4, P < 0.001). Correlations were found between specific neuropathic pain symptom clusters and quantitative sensory testing: paroxysmal pain with cold (ρ = −0.4; P = 0.008) and heat pain thresholds (ρ = 0.5; P = 0.003), burning pain with mechanical detection (ρ = −0.4; P = 0.015) and mechanical pain thresholds (ρ = −0.4, P < 0.013), evoked pain with mechanical pain threshold (ρ = −0.3; P = 0.047). Logistic regression showed that the combination of cold hypoesthesia on quantitative sensory testing, the Neuropathic Pain Symptom Inventory, and the allodynia intensity on bedside examination explained 77% of the occurrence of neuropathic pain. These findings provide insights into the clinical-psychophysics relationships in central post-stroke pain and may assist more precise distinction of neuropathic from non-neuropathic post-stroke pain in clinical practice and in future trials