165 resultados para Instruments de percussió


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This paper presents the design and implementation of an embedded soft sensor, i. e., a generic and autonomous hardware module, which can be applied to many complex plants, wherein a certain variable cannot be directly measured. It is implemented based on a fuzzy identification algorithm called ""Limited Rules"", employed to model continuous nonlinear processes. The fuzzy model has a Takagi-Sugeno-Kang structure and the premise parameters are defined based on the Fuzzy C-Means (FCM) clustering algorithm. The firmware contains the soft sensor and it runs online, estimating the target variable from other available variables. Tests have been performed using a simulated pH neutralization plant. The results of the embedded soft sensor have been considered satisfactory. A complete embedded inferential control system is also presented, including a soft sensor and a PID controller. (c) 2007, ISA. Published by Elsevier Ltd. All rights reserved.

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The design, construction, and characterization of a portable opto-coupled potentiostat are presented. The potentiostat is battery-powered, managed by a microcontroller, which implements cyclic voltammetry (CV) using suitable sensor electrodes. Its opto-coupling permits a wide range of current measurements, varying from mA to nA. Two software interfaces were developed to perform the CV measurement: a virtual instrument for a personal computer (PC) and a C-base interface for personal digital assistant (PDA). The potentiostat has been evaluated by detection of potassium ferrocyanide in KCl medium, both with macro and microelectrodes. There was good agreement between the instrumental results and those from commercial equipment.

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The aim of this work is the production and preliminary characterization of adsorbent new materials useful for sensor development. A new plasma chamber was simulated and designed in order to obtain multiple layers and/or composites in a single step. Plasma deposited organic fluorocompound and hexamethyldisilazane (HMDS) thin films were produced and tested as adsorbent layers. Chemical characterization used ellipsometry, Raman. infrared and X-ray photoelectron spectroscopy. Hydrophobic and oleophobic character were determined by contact angle measurements. Adsorption characteristics were evaluated using quartz crystal microbalance. Not only HMDS but also the fluorocompound can polymerize but intermixing and a double layer are only obtained in very narrow conditions. The films are adsorbent and mildly hydrophobic. Films deposited on a microchromatographic column can be used on sample pretreatment to remove and/or preconcentrate volatile organic Compounds. Therefore, with this approach it is possible to obtain films with different monomers on double layer or composites, with organic/inorganic materials or particles and use them on sample pretreatment for chemical analysis. (C) 2008 Elsevier B.V. All rights reserved.

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Rapid deforestation in the Brazilian Amazon, caused by economic, social, and policy factors, has focused global and national attention on protecting this valuable forest resource. In response, Brazil reformed its federal forest laws in 2006, creating new regulatory, development, and incentive policy instruments and institutions. Federal forestry responsibilities are maintained within the ministry of the environment; its regulatory agency responsibilities are divided among three different branches of the agency; many powers are delegated to states and municipalities; and a new private concession system is being developed. These reforms offer promise to improve forest protection and management in Brazil but must overcome significant institutional and social resistance for success.

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Brazilian agriculture covers about one-third of the land area and is expected to expand further We assessed the compliance of present Brazilian agriculture with environmental legislation and identified challenges for agricultural development connected to this legislation We found (i) minor illegal land use in protected areas under public administration, (ii) a large deficit in legal reserves and protected riparian zones on private farmland, and large areas of unprotected natural vegetation in regions experiencing agriculture expansion Achieving full compliance with the environmental laws as they presently stand would require drastic changes in agricultural land use, where large agricultural areas are taken out of production and converted back to natural vegetation The outcome of a full compliance with environmental legislation might not be satisfactory due to leakage, where pristine unprotected areas become converted to compensate for lost production as current agricultural areas are reconverted to protected natural vegetation. Realizing the desired protection of biodiversity and natural vegetation, while expanding agriculture to meet food and biofuel demand, may require a new approach to environmental protection New legal and regulatory instruments and the establishment of alternative development models should be considered

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Monoclonal antibodies (MAb) have been commonly applied to measure LDL in vivo and to characterize modifications of the lipids and apoprotein of the LDL particles. The electronegative low density lipoprotein (LDL(-)) has an apolipoprotein B-100 modified at oxidized events in vivo. In this work, a novel LDL-electrochemical biosensor was developed by adsorption of anti-LDL(-) MAb on an (polyvinyl formal)-gold nanoparticles (PVF-AuNPs)-modified gold electrode. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to characterize the recognition of LDL-. The interaction between MAb-LDL(-) leads to a blockage in the electron transfer of the [Fe(CN)(6)](4-)/K(4)[Fe(CN)(6)](3-) redox couple, which may could result in high change in the electron transfer resistance (R(CT)) and decrease in the amperometric responses in CV analysis. The compact antibody-antigen complex introduces the insulating layer on the assembled surface, which increases the diameter of the semicircle, resulting in a high R(CT), and the charge transferring rate constant k(0) decreases from 18.2 x 10(-6) m/s to 4.6 x 10(-6) m/s. Our results suggest that the interaction between MAb and lipoprotein can be quantitatively assessed by the modified electrode. The PVF-AuNPs-MAb system exhibited a sensitive response to LDL(-), which could be used as a biosensor to quantify plasmatic levels of LDL(-). (C) 2011 Elsevier B.V. All rights reserved.

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Wild chamomile (Matricaria chamomilla L.) is one of the most popular herbal materials with both internal and external use to cure different health disturbances. As a consequence of its origin, chamomile could carry various microbial contaminants which offer different hazards to the final consumer. Reduction of the microbial load to the in force regulation limits represents an important phase in the technological process of vegetal materials, and the electron beam treatment might be an efficient alternative to the classical methods of hygienic quality assurance. The purpose of the study was to analyze the potential application of the electron beam treatment in order to assure the microbial safety of the wild chamomile. Samples of chamomile dry inflorescences were treated in electron beam (e-beam) of 6 MeV mean energy, at room temperature and ambient pressure. Some loss of the chemical compounds with bioactive role could be noticed, but the number of microorganisms decreased as a function on the absorbed dose. Consequently, the microbial quality of studied vegetal material inflorescences was improved by e-beam. irradiation. (C) 2008 Elsevier B.V. All rights reserved.

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Background and purpose: The effects of centrally administered cannabinoids on body core temperature (Tc) and the contribution of endogenous cannabinoids to thermoregulation and fever induced by lipopolysaccharide (LPS) (Sigma Chem. Co., St. Louis, MO, USA) were investigated. Experimental approach: Drug-induced changes in Tc of male Wistar rats were recorded over 6 h using a thermistor probe (Yellow Springs Instruments 402, Dayton, OH, USA) inserted into the rectum. Key results: Injection of anandamide [(arachidonoylethanolamide (AEA); Tocris, Ellisville, MO, USA], 0.01-1 mu g i.c.v. or 0.1-100 ng intra-hypothalamic (i.h.), induced graded increases in Tc (peaks 1.5 and 1.6 degrees C at 4 h after 1 mu g i.c.v. or 10 ng i.h.). The effect of AEA (1 mu g, i.c.v.) was preceded by decreases in tail skin temperature and heat loss index (values at 1.5 h: vehicle 0.62, AEA 0.48). Bell-shaped curves were obtained for the increase in Tc induced by the fatty acid amide hydrolase inhibitor [3-(3-carbamoylphenyl)phenyl] N-cyclohexylcarbamate (Cayman Chemical Co., Ann Arbor, MI, USA) (0.001-1 ng i.c.v.; peak 1.9 degrees C at 5 h after 0.1 ng) and arachidonyl-2-chloroethylamide (ACEA; Tocris) (selective CB(1) agonist; 0.001-1 mu g i.c.v.; peak 1.4 degrees C 5 h after 0.01 mu g), but (R,S)-(+)-(2-Iodo-5-nitrobenzoyl)-[1-(1-methyl-piperidin-2-ylmethyl)-1H-indole-3-yl] methanone (Tocris) (selective CB(2) agonist) had no effect on Tc. AEA-induced fever was unaffected by i.c.v. pretreatment with 6-Iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indole-3-yl](4-methoxyphenyl) methanone (Tocris) (selective CB(2) antagonist), but reduced by i.c.v. pretreatment with N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251; Tocris) (selective CB(1) antagonist). AM251 also reduced the fever induced by ACEA or LPS. Conclusions and implications: The endogenous cannabinoid AEA induces an integrated febrile response through activation of CB(1) receptors. Endocannabinoids participate in the development of the febrile response to LPS constituting a target for antipyretic therapy.

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Objective. To investigate the modes of water supply and the perception concerning the problems caused by this water among residents of a neighborhood without public supply of water, settled in an area previously used as a garbage dump in the city of Manaus, Brazil. Methods. One hundred and sixty-two semi-structured household interviews were conducted. In addition, a focal group with teachers from a local public school and a meeting with residents were held. The instruments employed focused on the perception and modes of water use and on the process of exposure to chemical contaminants through water. Results. Untreated well water was used by most families. This water was considered to be ""good"" by 64.8% of the individuals interviewed. Most residents (88.3%) declared knowledge about the garbage dump. Of these, 77.6% stated that the garbage dump caused health and environmental problems. However, qualitative analysis of the responses revealed that the residents were not aware of contamination by chemical elements or of the consequences of such contamination. The activities carried out with teachers revealed that they were partially aware of the problem, but did not design interventions to address the issue. In a meeting with neighborhood residents, the presence of social activism concerning the problem was identified, but it did not extend beyond the neighborhood or reach governmental spheres. Conclusions. The study identified a situation of critical exposure that tends to be maintained as a result of misperceptions and lack of social mobilization. The dissemination of research results to teachers and residents was useful to empower subjects.

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The purpose of this in vitro study was to verify through micro tensile bond test the bond strength of an adhesive system irradiated with Nd:YAG laser in dentine previously treated with Er:YAG laser. Twenty caries free extracted human third molars were used. The teeth were divided in four experimental groups (n = 5): (G1) control group; (G2) irradiation of the adhesive system with the Nd:YAG laser; (G3) dentin treatment with Er:YAG laser; (G4) dentin treatment with Er:YAG laser followed by the irradiation of the adhesive system with Nd:YAG laser. The Er:YAG laser fluency parameter for the dentin treatment was of 60 J/cm(2). ne adhesive system was irradiated with the Nd:YAG laser with fluency of 100 J/cm(2). Dental restorations were performed with Adper Single Bond 2/Z250. One tooth from each group was prepared for the evaluation of the adhesive interface under SEM and bond failure tests were also performed and evaluated. The statistical analysis showed statistical significant difference between the groups G1 and G3, G1 and G4, G2 and G3, and G2 and G4; and similarity between the groups G1 and G2, and G3 and G4. The adhesive failures were predominant in all the experimental groups. The SEM analysis showed an adhesive interface with features confirming the results of the mechanical tests. The Nd:YAG laser on the adhesive system did not influence the bond strength in dentin treated or not with the Er:YAG laser.

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This article intends to rationally reconstruct Locke`s theory of knowledge as incorporated in a research program concerning the nature and structure of the theories and models of rationality. In previous articles we argued that the rationalist program can be subdivided into the classical rationalistic subprogram, which includes the knowledge theories of Descartes, Locke, Hume and Kant, the neoclassical subprogram, which includes the approaches of Duhem, Poincare and Mach, and the critical subprogram of Popper. The subdivision results from the different views of rationality proposed by each one of these subprograms, as well as from the tools made available by each one of them, containing theoretical instruments used to arrange, organize and develop the discussion on rationality, the main one of which is the structure of solution of problems. In this essay we intend to reconstruct the assumptions of Locke`s theory of knowledge, which in our view belongs to the classical rationalistic subprogram because it shares with it the thesis of the identity of (scientific) knowledge and certain knowledge.

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This study discusses the use of loyalty programs and Customer perception in, agricultural market. The theoretical review includes relationship marketing, its objectives, dimensions and instruments, and loyalty programs. The method for the empirical part consisted on qualitative research, through a case study conducted at one of the largest crop protection chemical companies in Brazil. The case is representative once this company was pioneer in its segment in adopting the customer relationship management. (CRM) approach to-their clients: It has been a consensus that customer relationship is a tool to amplify the Customer share. This.,is so, due the. increasing competition generated by the entrance of generic products and the retaliation actions adopted by the multinational groups. The case study includes a market overview, a description of the company, its loyalty program, the image of the program from the customer`s perspective, and the main results acquired with the CRM program. The Study also presents some recommendations for-companies that are pursuing strategies to. increase their customer share through loyalty programs.

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Purpose - The purpose of this research is to shed light on the main barriers faced by Mozambican micro and small enterprises (MSEs) and their implications in respect to the support policies available for these enterprises. Design/methodology/approach - A literature review was made on those barriers faced by the MSEs and on the policies and governmental instruments of assistance available for MSEs. Then, a two-step research was conducted. The first phase consisted of collecting data from 21 MSEs in Mozambique, mainly by means of interviews where the main barriers faced by those interviewed were identified and hence, this led to the second phase, which was interviewing governmental/support entities in order to know what they had done to minimize those barriers which had been identified by the entrepreneurs. Findings - The results show that financial and competitive barriers are the main barriers faced by the analyzed MSEs. These barriers vary according to the field of activity of the enterprises. Originality/value - This study serves to enrich the state of the art on the subject of smaller enterprises in Africa and will specially. help to fill the lack of academic research available about Mozambique.

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Techniques applying digital images increasingly have been used in biology, medicine, physics, and other research areas. The image coordinates can represent light intensities values to be detected by a CCD. Based on this concept, a photometric system composed of a LED source and a digital camera as a detector was used for optical density measurements. Standards for permanganate, glucose, and protein solutions were detemined by colorimetric methods using our device. Samples of protein of Pasteurella mutocida bacteria membrane and, also, fractions of rabbit kidney membrane, rich in Na, K-ATPase, with unknown concentrations were dosed through the Hartree method using our photometric system.

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New differential linear coherent scattering coefficient, mu(CS), data for four biological tissue types (fat pork, tendon chicken, adipose and fibroglandular human breast tissues) covering a large momentum transfer interval (0.07 <= q <= 70.5 nm(-1)), resulted from combining WAXS and SAXS data, are presented in order to emphasize the need to update the default data-base by including the molecular interference and the large-scale arrangements effect. The results showed that the differential linear coherent scattering coefficient demonstrates influence of the large-scale arrangement, mainly due to collagen fibrils for tendon chicken and fibroglandular breast samples, and triacylglycerides for fat pork and adipose breast samples at low momentum transfer region. While, at high momentum transfer, the mu(CS) reflects effects of molecular interference related to water for tendon chicken and fibroglandular samples and, fatty acids for fat pork and adipose samples. (C) 2009 Elsevier B.V. All rights reserved.