Experimental and theoretical study of workpiece temperature when end milling hardened steels using (TiAl)N-coated and PcBN-tipped tools

The present work shows an experimental and theoretical study on heat flow when end milling, at high-speed, hardened steels applied to moulds and dies. AISI H13 and AISI D2 steels were machined with two types of ball nose end mills: coated with (TiAl)N and tipped with PcBN. The workpiece geometry was designed to simulate tool-workpiece interaction in real situations found in mould industries, in which complex surfaces and thin walls are commonly machined. The compressed and cold air cooling systems were compared to dry machining Results indicated a relatively small temperature variation, with higher range when machining AISI D2 with PcBN-tipped end mill. All cooling systems used demonstrated good capacity to remove heat from the machined surface, especially the cold air. Compressed air was the most indicated to keep workpiece at relatively stable temperature. A theoretical model was also proposed to estimate the energy transferred to the workpiece (Q) and the average convection coefficient ((h) over bar) for the cooling systems used. The model used a FEM simulation and a steepest decent method to find the best values for both variables. (c) 2007 Elsevier B.V. All rights reserved.

Molecular tools and analytical approaches for the characterization of farm animal genetic diversity

Genetic studies of livestock populations focus on questions of domestication, within- and among-breed diversity, breed history and adaptive variation. In this review, we describe the use of different molecular markers and methods for data analysis used to address these questions. There is a clear trend towards the use of single nucleotide polymorphisms and whole-genome sequence information, the application of Bayesian or Approximate Bayesian analysis and the use of adaptive next to neutral diversity to support decisions on conservation.

Open and standardized tools for smart transducer networking

IEEE 1451 Standard is intended to address the smart transducer interfacing problematic in network environments. Usually, proprietary hardware and software is a very efficient solution to in planent the IEEE 1451 normative, although can be expensive and inflexible. In contrast, the use of open and standardized tools for implementing the IEEE 1451 normative is proposed in this paper. Tools such as Java and Phyton programming languages, Linux, programmable logic technology, Personal Computer resources and Ethernet architecture were integrated in order to constructa network node based on the IEEE 1451 standards. The node can be applied in systems based on the client-server communication model The evaluation of the employed tools and expermental results are presented. © 2005 IEEE.

Methods and tools for encoding the WordNet.Br sentences, concept glosses, and conceptual-semantic relations

This paper presents the overall methodology that has been used to encode both the Brazilian Portuguese WordNet (WordNet.Br) standard language-independent conceptual-semantic relations (hyponymy, co-hyponymy, meronymy, cause, and entailment) and the so-called cross-lingual conceptual-semantic relations between different wordnets. Accordingly, after contextualizing the project and outlining the current lexical database structure and statistics, it describes the WordNet.Br editing GUI that was designed to aid the linguist in carrying out the tasks of building synsets, selecting sample sentences from corpora, writing synset concept glosses, and encoding both language-independent conceptual-semantic relations and cross-lingual conceptual-semantic relations between WordNet.Br and Princeton WordNet © Springer-Verlag Berlin Heidelberg 2006.

Applying GIS tools for analysing urban thermal environment

A methodology for analyzing the solar access and its influence on both air temperature and thermal comfort of the urban environment was here developed by applying the potentiality of GIS tools. Urban canyons in a specific area of a Brazilian medium sized city were studied. First, a computational algorithm was applied in order to allow the determination of sky view factors (SVF) and sun-paths in urban canyons. Then, air temperatures in 40 measurement points were collected within the study area. Solar radiation values of these canyons were determined and subsequently stored in a GIS database. The creation of thermal maps for the whole neighbourhood was possible due to a statistical treatment of the data, by promoting the interpolation of values. All data could then be spatially cross-examined. In addition, thermal comfort maps for summer and winter periods were generated. The methodology allowed the identification of thermal tendencies within the neighbourhood, what can be useful in the conception of guidelines for urban planning purposes.

Comparative study on turning CI and CGI using silicon nitride cutting tools

There has been a great interest for improving the machining of cast iron materials in the automotive and other industries. Comparative studies for tool used to machine grey cast iron (CI) and compacted graphite iron (CGI) on dry machining were also performed in order to find out why in this case the tool lifetime is not significantly higher. However the machining these materials while considering turning with the traditional high-speed steel and carbide cutting tools present any disadvantages. One of these disadvantages is that all the traditional machining processes involve the cooling fluid to remove the heat generated on workpiece due to friction during cutting. This paper present a new generation of ceramic cutting tool exhibiting improved properties and important advances in machining CI and CGI. The tool performance was analyzed in function of flank wear, temperature and roughness, while can be observed that main effects were found for tool wear, were abrasion to CI and inter-diffusion of constituting elements between tool and CGI, causing crater. However the difference in tool lifetime can be explained by the formation of a MnS layer on the tool surface in the case of grey CI. This layer is missing in the case of CGI.

Study of cutting forces on machinability properties of gray cast iron using new ceramics cutting tools

During gray cast iron cutting, the great rate of mechanical energy from cutting forces is converted into heat. Considerable heat is generated, principally in three areas: the shear zone, rake face and at the clearance side of the cutting edge. Excessive heat will cause undesirable high temperature in the tool which leads to softening of the tool and its accelerated wear and breakage. Nowadays the advanced ceramics are widely used in cutting tools. In this paper a composition special of Si3N4 was sintering, characterized, cut and ground to make SNGN120408 and applyed in machining gray cast iron with hardness equal 205 HB in dry cutting conditions by using digital controlled computer lathe. The tool performance was analysed in function of cutting forces, flank wear, temperature and roughness. Therefore metal removing process is carried out for three different cutting speeds (300 m/min, 600 m/min, and 800 m/min), while a cutting depth of 1 mm and a feed rate of 0.33 mm/rev are kept constant. As a result of the experiments, the lowest main cutting force, which depends on cutting speed, is obtained as 264 N at 600 m/min while the highest main cutting force is recorded as 294 N at 300 m/min.

Interactive DC-DC converters tools for instant design and education

This paper deals with the usage of interactive simulations tools to serve as an oriented design tool for the lectures and laboratory experiments in the power electronics courses. A dynamic and interactive visualization of simulations for idealized converters in steady state are provided by the proposed educational tools, allowing students to acquire qualification in non-isolated DC-DC converters, without previous circuitry knowledge, either without the usage of sophisticated simulation packages. The interaction with proposed simulation tools can be accomplished by student using direct or graphic mode. In direct mode the parameters related with the design of converter can be inserted simply editing default values presented in textboxes, while in the graphic mode students interact indirectly with design information by manipulating visual widgets. In order to corroborate the proposed interactive simulation tools, comparisons of results from buck-boost and boost converters on proposed tools and a well-known simulator package with those on experimental evaluation from laboratory classes were presented. © 2009 IEEE.

Development of ceramic cutting tools for future application on dry machining

Advanced ceramic materials constitute a mature technology with a very broad base of current and potential applications and a growing list of material compositions. Within the advanced ceramics category, silicon nitride based ceramics are wear-resistant, corrosion-resistant and lightweight materials, and are superior to many materials with regard to stability in high-temperature environments. Because of this combination the silicon nitride ceramics have an especially high potential to resolve a wide number of machining problems in the industries. Presently the Si3N4 ceramic cutting tool inserts are developed using additives powders that are pressed and sintered in the form of a cutting tool insert at a temperature of 1850 °C using pressureless sintering. The microstructure of the material was observed and analyzed using XRD, SEM, and the mechanical response of this array microstructure was characterized for hardness Vickers and fracture toughness. The results show that Si3N4/20 wt.% (AlN and Y 2O3) gives the best balance between hardness Vickers and fracture toughness. The Si3N4/15 wt.% (AlN and Y 2O3) composition allows the production of a very fine-grained microstructure with low decreasing of the fracture toughness and increased hardness Vickers. These ceramic cutting tools present adequate characteristics for future application on dry machining. © (2010) Trans Tech Publications.

Computer tools to aid the learning and design steps for photovoltaic systems

This paper presents novel simulation tools to assist the lecturers about learning processes on renewable energy sources, considering photovoltaic (PV) systems. The PV behavior, functionality and its interaction with power electronic converters are investigated in the simulation tools. The main PV output characteristics, I (current) versus V (voltage) and P (power) versus V (voltage), were implemented in the tools, in order to aid the users for the design steps. In order to verify the effectiveness of the developed tools the simulation results were compared with Matlab. Finally, a prototype was implemented with the purpose to compare the experimental results with the results from the proposed tools, validating its operational feasibility. © 2011 IEEE.

Free tools and strategies for the generation of 3D finite element meshes: Modeling of the cardiac structures

The Finite Element Method is a well-known technique, being extensively applied in different areas. Studies using the Finite Element Method (FEM) are targeted to improve cardiac ablation procedures. For such simulations, the finite element meshes should consider the size and histological features of the target structures. However, it is possible to verify that some methods or tools used to generate meshes of human body structures are still limited, due to nondetailed models, nontrivial preprocessing, or mainly limitation in the use condition. In this paper, alternatives are demonstrated to solid modeling and automatic generation of highly refined tetrahedral meshes, with quality compatible with other studies focused on mesh generation. The innovations presented here are strategies to integrate Open Source Software (OSS). The chosen techniques and strategies are presented and discussed, considering cardiac structures as a first application context. © 2013 E. Pavarino et al.

Habitat monitoring and genotoxicity in Ucides cordatus (Crustacea: Ucididae), as tools to manage a mangrove reserve in southeastern Brazil

In Brazil, the state of São Paulo contains both preserved areas (Juréia-Itatins Ecological Station) and extremely impacted ones (Cubatão Municipality). This study evaluated the concentrations of five metals (Cu, Cd, Cr, Pb, and Hg) in two mangroves with different levels of anthropogenic impact and the apparent genotoxicity to Ucides cordatus. Water and sediment samples were obtained, and metal concentrations were determined with an atomic absorption spectrophotometer. The genotoxic impact was quantified based on the number of micronucleated cells per 1,000 analyzed (MN‰), using hemolymph slides stained with Giemsa. Metal concentrations in water were below the detection limit, except for lead, although no significant difference was observed between the areas (P > 0.05). Sediment from Cubatão had higher concentrations of Cd, Pb, Cr, and Cu than sediment from Juréia-Itatins (P < 0.05), but no significant differences in metal concentrations were detected among depth strata of the sediment (P > 0.05). Crabs from Cubatão had a 2.6 times higher mean frequency of micronucleated cells (5.2 ± 1.8 MN‰) than those from Juréia-Itatins (2.0 ± 1.0 MN‰; P < 0.0001). The more-polluted conditions found in the mangrove sediments of Cubatão were reflected in the micronucleus assay, demonstrating their genotoxic effect; however, genetic damage should be attributed to a synergistic effect with other kinds of pollutants previously recorded in different environments of Cubatão. U. cordatus proved to be an excellent bioindicator of mangrove pollution. This study established, for the first time, the normal frequency of MN‰ in a population of this species within an ecological station. © 2013 Springer Science+Business Media Dordrecht.

Different tools for estimating cardiovascular risk in Brazilian postmenopausal women

Objective: To compare estimation of cardiovascular risk using the Framinghan Risk Score (FRS) and the presence of the metabolic syndrome (MetS) in postmenopausal women to prevent primary cardiovascular disease (CVD). Methods: This cross-sectional study included 497 Brazilian women (aged 45 years and amenorrhea >12months). Cardiovascular risk was calculated using the FRS that includes age, total cholesterol, HDL, systolic blood pressure and smoking status. Women showing three or more of the following criteria were diagnosed with MetS: waist circumference (WC) >88cm, blood pressure 130/85mmHg, triglycerides 150mg/dl, HDL<50mg/dl and glucose 100mg/dl. For statistical analysis, the Chi-square, Fisher's exact, and logistic regression (odds ratio-OR) were used. Results: The mean age was 55.3±7.0 years and time since menopause 7.2±5.9 years. Based on FRS, 72.4% of women were classified as low-risk, 16.5% moderate risk and 11.1% a high-risk. MetS was identified in 40% of the women, and 46.2% were considered of moderate risk for CVD, while 84.9% of those without MetS were classified as low-risk (p<0.001). The risk for CVD increased significantly with age at menopause (OR1.10; 95% CI, 1.04-1.17), time since menopause (OR1.13; 95% CI, 1.08-1.18), elevated triglycerides (OR1.03; 95% CI, 1.0-1.10) and presence of MetS (OR1.72; 95% CI 1.48-1.84). Conclusions: By using only FRS to estimate cardiovascular risk, a substantial number of postmenopausal women showing evidence of MetS were not identified, even though women with MetS are at higher risk of CVD. © 2013 Informa UK Ltd.

Use of Chemometric Tools to Determine the Source of Metals in Sediments of the Rivers of the Turvo/Grande Hydrographical Basin, Sao Paulo State, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)