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981.
Marco CECCARELLI 《Frontiers of Mechanical Engineering》2014,9(4):308
Human-like torso features are essential in humanoid robots. In this paper problems for design and operation of solutions for a robotic torso are discussed by referring to experiences and designs that have been developed at Laboratory of Robotics and Mechatronics (LARM) in Cassino, Italy. A new solution is presented with conceptual views as waist-trunk structure that makes a proper partition of the performance for walking and arm operations as sustained by a torso. 相似文献
982.
Eukaryotic organisms such as plants are unable to utilise nitrogen gas (N2) directly as a source of this essential element and are dependent either on its biological conversion to ammonium by diazotrophic prokaryotes, or its supply as chemically synthesised nitrate fertiliser. The idea of genetically engineering crops with the capacity to fix N2 by introduction of the bacterial nitrogenase enzyme has long been discussed. However, the expression of an active nitrogenase must overcome several major challenges: the coordinated expression of multiple genes to assemble an enzyme complex containing several different metal cluster co-factors; the supply of sufficient ATP and reductant to the enzyme; the enzyme’s sensitivity to oxygen; and the intracellular accumulation of ammonium. The chloroplast of plant cells represents an attractive location for nitrogenase expression, but engineering the organelle’s genome is not yet feasible in most crop species. However, the unicellular green alga Chlamydomonas reinhardtii represents a simple model for photosynthetic eukaryotes with a genetically tractable chloroplast. In this review, we discuss the main advantages, and limitations, of this microalga as a testbed for producing such a complex multi-subunit enzyme. Furthermore, we suggest that a minimal set of six transgenes are necessary for chloroplast-localised synthesis of an ‘Fe-only’ nitrogenase, and from this set we demonstrate the stable expression and accumulation of the homocitrate synthase, NifV, under aerobic conditions. Arguably, further studies in C. reinhardtii aimed at testing expression and function of the full gene set would provide the groundwork for a concerted future effort to create nitrogen-fixing crops. 相似文献
983.
Fabrizio Dallari Gino Marchet Marco Melacini 《The International Journal of Advanced Manufacturing Technology》2009,42(1-2):1-12
Numerous design and cost parameters, combined with an endless variety of equipment types, make it difficult to choose the right order picking system (OPS). The purpose of this study is to develop a methodology to support warehouse designers in choosing the most suitable OPS. By developing a new OPS classification, we carried out an in-depth survey on over 68 distribution centres that have been recently built in Italy. The results of the critical analysis allowed developing a design methodology to choose the most suitable OPS. This methodology has been integrated in the structured procedure for OPS design, developed by Yoon and Sharp (IIE Trans 28:379–389, 1996). Finally, a numerical case study is presented to illustrate the application of the proposed design methodology. 相似文献
984.
STURM Volker EILERS Daniel WERHEIT Patrick CHIAROTTI Ugo VOLPONI Vincenzo DE MIRANDA Uggero ZANI Marco MAKOWE Joachim 《冶金分析》2012,32(6):18-23
评估了激光诱导击穿光谱(LIBS)在废钢料分析中的使用,以用于电弧炉中废钢料的元素监测。开发了一个LIBS原型用于现场试验,并将其安装在位于废钢料填充区和电弧炉之间的钟摆式输送槽上。LIBS原型距离电弧炉大约25 m。废钢料填充的钟摆式输送槽的宽度和深度分别为大约2 m和1 m。调整废钢料的平均速率在0.3~5.5 m/min的范围内,使之满足电弧炉的装填要求,从而使废钢料的生产能力达到100 t/h。在安装地点,低合金废钢料中高含量硅的检测基本上对电弧炉控制的改进很有帮助。由于测量体积受限在600×600×180 mm3,研发的原型仅检测了一小部分的钢料表面。但是,在线LIBS测量还是显示了在工业环境下测定高硅废钢料样品的能力。为了拓展在加料、过程控制及管理上的应用,应增加测量体积从而进一步提高其性能。 相似文献
985.
Self-locking analysis in closed kinematic chains is sometimes likened to kinematic singularity analysis, especially when mechanisms are characterized by more than one degree of freedom. Although in singular configurations a mechanism is obviously locked-up since joint constraint reactions and friction forces rise to infinity, this approach identifies only a condition sufficient for self-locking, while the phenomenon actually occurs in a larger domain, the size of which depends on the values of friction coefficients.The paper proposes a definition of self-locking for multi degrees of freedom mechanisms and presents an algorithm for computing the geometrical locus that corresponds to a specific self-locking configuration. This methodology is then demonstrated on a simple parallel kinematic mechanism with two degrees of freedom. 相似文献
986.
Effect of drying temperature on polyphenolic content and antioxidant activity of apricots 总被引:1,自引:0,他引:1
Monica A. Madrau Amalia Piscopo Anna M. Sanguinetti Alessandra Del Caro Marco Poiana Flora V. Romeo Antonio Piga 《European Food Research and Technology》2009,228(3):441-448
This study was carried out in order to check for the influence of drying parameters on the phenolic compounds and antioxidant
activity on two apricot cultivars (Pelese and Cafona) using two sets of air drying temperatures: (1) air temperature at 55
°C; (2) air temperature at 75 °C. Whole fresh and dried fruits were assessed for: phenolics, ascorbic acid, antioxidant activity
and redox potential (all parameters were calculated on a dry matter basis). Analysis of data shows that the decrease in chlorogenic
and neochlorogenic acid in Cafona cultivar is higher at the lower drying temperature. Catechin showed the same behaviour of
hydroxycinnamic acids in both cultivars, while the decrease in the other compounds was significantly more marked in the sample
dried at 75 °C. The antioxidant activity increased significantly in Cafona fruits and this increase was confirmed by a diminution
of the redox potential. 相似文献
987.
Agnese Filippello Stefania Di Mauro Alessandra Scamporrino Roberta Malaguarnera Sebastiano Alfio Torrisi Gian Marco Leggio Antonino Di Pino Roberto Scicali Francesco Purrello Salvatore Piro 《International journal of molecular sciences》2021,22(13)
Intestinal organoids are used to analyze the differentiation of enteroendocrine cells (EECs) and to manipulate their density for treating type 2 diabetes. EEC differentiation is a continuous process tightly regulated in the gut by a complex regulatory network. However, the effect of chronic hyperglycemia, in the modulation of regulatory networks controlling identity and differentiation of EECs, has not been analyzed. This study aimed to investigate the effect of glucotoxicity on EEC differentiation in small intestinal organoid platforms. Mouse intestinal organoids were cultured in the presence/absence of high glucose concentrations (35 mM) for 48 h to mimic glucotoxicity. Chronic hyperglycemia impaired the expression of markers related to the differentiation of EEC progenitors (Ngn3) and L-cells (NeuroD1), and it also reduced the expression of Gcg and GLP-1 positive cell number. In addition, the expression of intestinal stem cell markers was reduced in organoids exposed to high glucose concentrations. Our data indicate that glucotoxicity impairs L-cell differentiation, which could be associated with decreased intestinal stem cell proliferative capacity. This study provides the identification of new targets involved in new molecular signaling mechanisms impaired by glucotoxicity that could be a useful tool for the treatment of type 2 diabetes. 相似文献
988.
Sleep-related car crashes: risk perception and decision-making processes in young drivers 总被引:2,自引:0,他引:2
Lucidi F Russo PM Mallia L Devoto A Lauriola M Violani C 《Accident; analysis and prevention》2006,38(2):302-309
The aim of the present study is to analyse factors affecting worries, coping strategies and decisions of young drivers regarding the risk of sleep-related car crashes. Furthermore, the study also analyses whether framing the same information about sleepiness in two different linguistic forms influences: (1) the evaluation of the level of risk associated to a specific level of drowsiness (Attribute Framing problem); (2) the willingness to enact strategies to "prevent" sleepiness before night-time driving (Goal Framing problem); (3) the choice between two different ways, both of equal expected efficacy, of lowering drowsiness (Risky decision-making Framing problem). Six hundred and ninety-five young drivers [(57.6% females, 42.4% males); mean age 20.85 years (S.D.=1.2)] answered questions on drive risk perception and sleepiness, on nocturnal driving experience and on the strategies to deal with driver sleepiness, responding to one of the two different versions of the framed problems. A sub-sample of 130 participants completed the framed problems in both versions. The results show that experiences of sleep attacks and nocturnal driving frequency in the past 6 months affect both risk perception and the preventive strategies adopted. Furthermore, the manipulation on two out of the three problems (attribute and risky decision-making frames) significantly affected the respondents' evaluation. 相似文献
989.
Carlotti M Brizzi G Papandrea E Prevedelli M Ridolfi M Dinelli BM Magnani L 《Applied optics》2006,45(4):716-727
We present a new retrieval model designed to analyze the observations of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), which is on board the ENVironmental SATellite (ENVISAT). The new geo-fit multitarget retrieval model (GMTR) implements the geo-fit two-dimensional inversion for the simultaneous retrieval of several targets including a set of atmospheric constituents that are not considered by the ground processor of the MIPAS experiment. We describe the innovative solutions adopted in the inversion algorithm and the main functionalities of the corresponding computer code. The performance of GMTR is compared with that of the MIPAS ground processor in terms of accuracy of the retrieval products. Furthermore, we show the capability of GMTR to resolve the horizontal structures of the atmosphere. The new retrieval model is implemented in an optimized computer code that is distributed by the European Space Agency as "open source" in a package that includes a full set of auxiliary data for the retrieval of 28 atmospheric targets. 相似文献
990.
A Portland cement process was taken into consideration and monitored for one month with respect to polluting emissions, fuel and raw material physical-chemical properties, and operative conditions. Soft models, based on linear (partial least-squares, PLS, and principal component regression, PCR) and nonlinear (artificial neural networks, ANNs) approaches, were employed to predict the polluting emissions. The predictive ability of the three regression methods was evaluated by means of the partition of the dataset by Kohonen self-associative maps into both a training and a test set. Then, a "leave-more-out" approach, based on the use of a training set, a test set, and a production set, was adopted. The training set was used to build the models, the test set was used to select the number of latent variables or the neural network training endpoint, and the production set was used to produce genuine predictions. ANNs proved to be much more effective in prediction with respect to PLS and PCR and, at least in the case of SO2 and dust, provided a predictive ability comparable with the experimental estimated uncertainty of the response. This showed that it is possible to satisfactorily predict the two responses. Such a prediction will result in the prevention of environmental and legal problems connected to the polluting emissions. 相似文献