923 resultados para metal trace analysis
Resumo:
This study will concentrate on Product Data Management (PDM) systems, and sheet metal design features and classification. In this thesis, PDM is seen as an individual system which handles all product-related data and information. The meaning of relevant data is to take the manufacturing process further with fewer errors. The features of sheet metals are giving more information and value to the designed models. The possibility of implementing PDM and sheet metal features recognition are the core of this study. Their integration should make the design process faster and manufacturing-friendly products easier to design. The triangulation method is the basis for this research. The sections of this triangle are: scientific literature review, interview using the Delphi method and the author’s experience and observations. The main key findings of this study are: (1) the area of focus in triangle (the triangle of three different point of views: business, information exchange and technical) depends on the person’s background and their role in the company, (2) the classification in the PDM system (and also in the CAD system) should be done using the materials, tools and machines that are in use in the company and (3) the design process has to be more effective because of the increase of industrial production, sheet metal blank production and the designer’s time spent on actual design and (4) because Design For Manufacture (DFM) integration can be done with CAD-programs, DFM integration with the PDM system should also be possible.
Resumo:
A small break loss-of-coolant accident (SBLOCA) is one of problems investigated in an NPP operation. Such accident can be analyzed using an experiment facility and TRACE thermal-hydraulic system code. A series of SBLOCA experiments was carried out on Parallel Channel Test Loop (PACTEL) facility, exploited together with Technical Research Centre of Finland VTT Energy and Lappeenranta University of Technology (LUT), in order to investigate two-phase phenomena related to a VVER-type reactor. The experiments and a TRACE model of the PACTEL facility are described in the paper. In addition, there is the TRACE code description with main field equations. At the work, calculations of a SBLOCA series are implemented and after the calculations, the thesis discusses the validation of TRACE and concludes with an assessment of the usefulness and accuracy of the code in calculating small breaks.
Resumo:
Currently, the power generation is one of the most significant life aspects for the whole man-kind. Barely one can imagine our life without electricity and thermal energy. Thus, different technologies for producing those types of energy need to be used. Each of those technologies will always have their own advantages and disadvantages. Nevertheless, every technology must satisfy such requirements as efficiency, ecology safety and reliability. In the matter of the power generation with nuclear energy utilization these requirements needs to be highly main-tained, especially since accidents on nuclear power plants may cause very long term deadly consequences. In order to prevent possible disasters related to the accident on a nuclear power plant strong and powerful algorithms were invented in last decades. Such algorithms are able to manage calculations of different physical processes and phenomena of real facilities. How-ever, the results acquired by the computing must be verified with experimental data.
Resumo:
Dept. of chemical oceanography, Cochin University of Science and Technology
Resumo:
This thesis Entitled Trace metal speciation in the cochin estuary.Natural waters provide a favourable environment for speciation studies because of the prevailing variable chemical matrix and the variety of metal forms which may exist there.An estuary is a mixing zone of riverine and oceanic waters with widely varying compositions where end members interact both physically and chemically. The trace element chemistry in the estuarine environment has been an area of considerable research in the past decades. The trace metal distribution in the Cochin estuary is considerably influenced by the tropical features of the location and by human activities. The lower Periyar river and the Cochin estuary have been particularly selected for this investigation in view of the impact of trace metals on the estuarine ecosystem as well as in attempt quantify the phenomenon of metal speciation in the waters of a tropical coastal plain waterbody. If the concentration in the water media is very low, then, many of the fractions that could be estimated by speciation schemes for metals will fall below the detection limits, a factor which is undesirable.The study would also delineate the features of metal speciation which modify the chemical regime of ionic elements that traverse natural boundaries in aquatic environments, especally in those tropical areas prone to multivariate geographical settings.
Resumo:
The main objective of the study is primarily to determine the magnitude of selected trace elements, the concentrations of which would possibly accelerate growth resulting in larger biomass and sustained period of exponential phase for economically viable harvest. The study on the effect of three trace elements namely Cu, Mn and Zn on two species of algae,ISOChrySiS galbana Parke and Synechocystib salina Wislouch under different conditions of salinity, PH and temperature involves several combinations for each metal, from which the relative set of conditions has been adduced. The scheme of the experiments was statistically designed for interpretation of data and factors were assessed and graded according to relative importance. The methodology adopted for data interpretation is analysis of variance by split-plot design method. The thesis has been divided into five chapters. The introductory chapter explains the relevance of the research work undertaken. Chapter 11 gives a review on the work pertaining to the above mentioned three trace elements in relation to nutrition as well as on the toxic aspects about which there is an abundance of literature. Chapter Ill presents a detailed description of the material and specialised methods followed for the study. The results and conclusions of the various experiments on effect of metals on growth and other physiological activities are discussed in Chapters IV and V.
Resumo:
The subsequent chapters of the Thesis deal with the toxic effects of mercury, copper, zinc und~1ead on these bivalve molluecs, their accumulation and distribution among various organs of the animals and also the motel retention winstica by the three species. Static biousauy tests have been conducted in these studies. It was found that the concentrations of the various metals studied in these organism are well below the permitted level given far ease ahellfienes (crab and ehrimgi and that these maliuscs are very good integrators ef trace metals from their environment and may be used as an indicator organism sf metal pallutaute. The present investigutionsemphaeie the need for a clean coastal water and gives a serious warning regarding the possiblc route of heavy metals in ta human body thraugh marine food chain.
Resumo:
Metal matrix composites (MMC) having aluminium (Al) in the matrix phase and silicon carbide particles (SiCp) in reinforcement phase, ie Al‐SiCp type MMC, have gained popularity in the re‐cent past. In this competitive age, manufacturing industries strive to produce superior quality products at reasonable price. This is possible by achieving higher productivity while performing machining at optimum combinations of process variables. The low weight and high strength MMC are found suitable for variety of components
Resumo:
The Cochin estuary (CE), which is one of the largest wetland ecosystems, extends from Thanneermukkam bund in the south to Azhikode in the north. It functions as an effluent repository for more than 240 industries, the characteristics of which includes fertilizer, pesticide, radioactive mineral processing, chemical and allied industries, petroleum refining and heavy metal processing industries (Thyagarajan, 2004). Studies in the CE have been mostly on the spatial and temporal variations in the physical, chemical and biological characteristics of the estuary (Balachandran et al., 2006; Madhu et al., 2007; Menon et al., 2000; Qasim 2003;Qasim and Gopinathan 1969) . Although several monitoring programs have been initiated in the CE to understand the level of heavy metal pollution, these were restricted to trace metals distribution (Balachandran et al., 2005) or the influence of anthropogenic inputs on the benthos and phytoplankton (Madhu et al., 2007;Jayaraj, 2006). Recently, few studies were carried out on microbial ecology in the CE(Thottathil et al 2008a and b;Parvathi et al., 2009and 2011; Thomas et al., 2006;Chandran and Hatha, 2003). However, studies on metal - microbe interaction are hitherto not undertaken in this estuary. Hence, a study was undertaken at 3 sites with different level of heavy metal concentration tounderstand the abundance, diversity and mechanisms of resistance in metal resistant bacteria and its impact on the nutrient regeneration. The present work has also focused on the response of heavy metal resistant bacteria towards antibacterial agent’s antibiotics and silver nanoparticles
Resumo:
A first step in interpreting the wide variation in trace gas concentrations measured over time at a given site is to classify the data according to the prevailing weather conditions. In order to classify measurements made during two intensive field campaigns at Mace Head, on the west coast of Ireland, an objective method of assigning data to different weather types has been developed. Air-mass back trajectories calculated using winds from ECMWF analyses, arriving at the site in 1995–1997, were allocated to clusters based on a statistical analysis of the latitude, longitude and pressure of the trajectory at 12 h intervals over 5 days. The robustness of the analysis was assessed by using an ensemble of back trajectories calculated for four points around Mace Head. Separate analyses were made for each of the 3 years, and for four 3-month periods. The use of these clusters in classifying ground-based ozone measurements at Mace Head is described, including the need to exclude data which have been influenced by local perturbations to the regional flow pattern, for example, by sea breezes. Even with a limited data set, based on 2 months of intensive field measurements in 1996 and 1997, there are statistically significant differences in ozone concentrations in air from the different clusters. The limitations of this type of analysis for classification and interpretation of ground-based chemistry measurements are discussed.
Resumo:
Emission of fine particles by mobile sources has been a matter of great concern due to its potential risk both to human health and the environment. Although there is no evidence that one sole component may be responsible for the adverse health outcomes, it is postulated that the metal particle content is one of the most important factors, mainly in relation to oxidative stress. Data concerning the amount and type of metal particles emitted by automotive vehicles using Brazilian fuels are limited. The aim of this study was to identify inhalable particles (PM10) and their trace metal content in two light-duty vehicles where one was fueled with ethanol while the other was fueled with gasoline mixed with 22% of anhydrous ethanol (gasohol); these engines were tested on a chassis dynamometer. The elementary composition of the samples was evaluated by the particle-induced x-ray emission technique. The experiment showed that total emission factors ranged from 2.5 to 11.8 mg/km in the gasohol vehicle, and from 1.2 to 3 mg/km in the ethanol vehicle. The majority of particles emitted were in the fine fraction (PM2.5), in which Al, Si, Ca, and Fe corresponded to 80% of the total weight. PM10 emissions from the ethanol vehicle were about threefold lower than those of gasohol. The elevated amount of fine particulate matter is an aggravating factor, considering that these particles, and consequently associated metals, readily penetrate deeply into the respiratory tract, producing damage to lungs and other tissues.
Resumo:
The region of Toledo River, Parana, Brazil is characterized by intense anthropogenic activities. Hence, metal concentrations and physical-chemical parameters of Toledo River water were determined in order to complete an environmental evaluation catalog. Samples were collected monthly during one year period at seven different sites from the source down the river mouth, physical-chemical variables were analyzed, and major metallic ions were measured. Metal analysis was performed by using the synchrotron radiation total reflection X-ray fluorescence technique. A statistical analysis was applied to evaluate the reliability of experimental data. The analysis of obtained results have shown that a strong correlation between physical-chemical parameters existed among sites 1 and 7, suggesting that organic pollutants were mainly responsible for decreasing the Toledo River water quality.