bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Sintering Temperature on the Celsian/Yttrium Silicate Oxidation Resistant Coatings for C/SiC Composite
Authors: Zheng Xiao Hui , Wang Chun Yu , Ding Song Tao , Liang Chi Yong
Published: October 2014

A novel celsian/yttrium silicate coating was deposited on carbon fiber reinforced silicon carbide matrix (C/SiC) composite, using BaO-Al2O3-SiO2 (BAS) glass andY2O3 powder as starting materials. The effects of sintering temperatures on microstructure and performance of coatings were studied. The results show that the final phases of sintered coatings are composed of celsian, yttrium silicate and remnant glass. The coating are dense, crack-free and pore-free in macroscopic scales when sintered at temperatures above 1400°C. The crystal grains in the coating grow too large, and the coating is loose in microstructure when sintered at temperatures higher than 1450°C. The coated samples sintered at 1450°C for 30min, which have the densest morphology and microstructure, have the lowest weight loss of 0.13 % after oxidation at 1500°C for 90 min.
Infrared Analysis on Pyrolysis Products of Flame Retardant Rigid Polyurethane Foam
Authors: Zhang Ze Jiang , Li Li Jun , Li Feng , He Jin , Gan Zi Qiong
Published: October 2014

Infrared spectra of the pyrolysis gases of polyurethane foam flame retarded by MPOP, MP, MC, magnesium hydroxide, or antimony trioxide flame retardants was analyzed online by FTIR method. At 600°C, the polyurethane foam flame retarded by MPOP, MP, MC, magnesium hydroxide or antimony trioxide flame retardants released more hydrogen cyanide than the pure polyurethane foam, proved that the MPOP, MP, MC and magnesium hydroxide flame retardants could change the law that the polyurethane released hydrogen cyanide. At 600 °C, the peak of C=O stretching vibration at 1730cm-1did not appear for the flame-retardant polyurethane, indicating that the flame retardants can make the polyurethane rapidly carbonize and the fewer C=O intermediate was produced. The absorbent peaks of the fire-retardant samples at 1604cm-1, 1538 cm-1, 1250 to 1230 cm-1and 1450cm-1implied that the flame retardants could delay the oxidative decomposition of the polyurethane component at 600 °C, so that more components may be carbonized. When increasing the pyrolysis temperature, the perlite would make polyurethane foam release fewer hydrogen cyanide.
Synthesis of Polymeric Schiff Base (PSB) Nanostructural Materials via Interfacial Polymerization
Authors: Dong Na , Tong Yong Chun , Wang Qi Zhao , Su Bi Tao
Published: October 2014

Nanostructural materials of polymeric Schiff base (PSB) have been selectively synthesized via interfacial polymerization (IP) by modifying the polymerization process. The effects of synthesizing methods, catalyst, the monomer concentration and the reaction time on the morphology of PSB nanostructural materials are investigated. The samples are characterized by TEM, FT-IR, UV-Vis, XRD, thermal analysis, and electrical conductivity measurement techniques. The results show that the PSB nanostructural materials, such as nanofilms and-rods, can be obtained via IP. Na+ and NH4+ ions act as shape-regulated agents. Na+ ion can control the growth of PSB nuclei along two-dimension to obtain PSB nanofilms and NH4+ is advantage to the growth of PSB nuclei along one-dimension to obtain PSB nanorods. It is also found that the polymer nanocrystals show high thermal stability and the iodine-doped polymer is a semiconductor material.
The Research Status and Applications of Atom Transfer Radical Polymerization
Authors: Sun Yong Lian , Zhu Bo , Zhou Shan Shan , Chen Bao Lei , Gao Jian , Li Yong Wei
Published: October 2014

ATRP is one of the most active fields in polymer science. The feature of ATRP is chain propagation by way of transfer of halide atom with or without the catalysis of transition mental compounds. The termination reaction between radicals is reduced by low concentration of free radicals under the control of the fast transfer. A variety of monomers including styrene, acrylates, methacrylates, and dienes can be used in this technique. ATRP is a simple and inexpensive process for controlled "living" radical polymerization leading to well-defined homopolymers and copolymers. In this paper, the mechanism, initiator, catalyst systems, polymerization mediums and conditions of ATRP are introduced, the prospect of ATRP is also discussed.
Synthetic Studies on (12S)-12-Hydroxymonocerin
Authors: Li Jun  Peng , Yang Han , Chen Jia Lin , Xiong Qing Feng , Cui Hao , Li Shi Hong
Published: October 2014

A novel approach to assemble the (12S)-12-Hydroxymonocerin’s core skeleton was developed in 29% overall yield, in which a three component Linchpin coupling, stereocontrolled reduction and an intramolecular Friedel-Crafts/Marson cyclization were utilized as key steps.
Study on Infiltration Characteristics and Stability of Excavated Loess Slope in an Industry Site
Authors: Wang Nian Qin , Han Bo , Liu Xiao Ling , Yu Zheng
Published: October 2014

In industrial construction of loess area, rainfall is one of the important factors inducing excavated slope instability. Take an industry site excavated loess slope in northern Shaanxi for example, using Geo-studio in steady flow state to analyze infiltration characteristics and stability of a loess slope. The results show that: (1) The influence of the X direction maximum locate at the free face of slope foot, Y direction maximum locate at the top of slope. (2) The upper slope larger permeability coefficient, the lower the permeability coefficient is smaller, aquiclude almost have no permeability, shows that the slope is loose soil, particles with skeleton structure, easy water infiltration, the farther down the soil compaction degree is high, the worse the infiltration capacity into the water, the permeability coefficient is smaller. (3) It is easy to produce water flow in aquiclude and slope toe. Then, it soften soil, reduced the shear strength of the soil. It can explain that aquiclude and free face on slope foot always is the structure plane shear outlet of slope.
Hot Deformation Behavior of 20CrMnTiH Steel Studied by Johnson-Cook Model and Genetic Algorithm
Authors: Chai Rong Xia , Guo Wei , Guo Chen
Published: October 2014

Hot compression tests of 20CrMnTiH steel are carried out in the strain rates range from 0.01s-1 to 10s-1 and in the temperature range from 973K to 1123K. The flow behaviors of 20CrMnTiH steel are described based on the analysis of true stress-true strain curves. The flow stress increases with the increasing of strain rate and the decreasing of deforming temperature. Johnson-Cook (J-C) model are used to analyze the hot deformation behaviors. In the constitutive model, material constants are determined based upon the experimental data. Genetic algorithm (GA) is proposed with the aim of optimizing the J-C model parameters. Good agreement is acquired by comparing of the experimental results with predicted results. It validates the efficiency of Johnson-Cook model in describing the material constitutive behavior.
Effects of Different Content of TiO2 on Crystallization Behavior and Properties of Li2O-ZnO-SiO2 Glass-Ceramics
Authors: Zhao Xiu Quan , Cao Zheng , Wu Yu Teng , Jiang Hong , Li Chang Jiu , Yu Lin , Shen Yang
Published: October 2014

Glass-ceramic materials of the Li2O-ZnO-SiO2 system, with various amounts of TiO2 added, have been prepared. The appropriate heat treatment temperatures were selected according to the information provided by the differential thermal analysis (DTA). X-ray diffraction (XRD) analysis demonstrated that in the LZS glass-ceramics system, the main phases are Li2ZnSiO4, cristobalite, tridymite and quartz. The scanning electron microscopy (SEM) revealed that crystals appear as lamellar and spherical particles in the glass-ceramics samples. In addition, the average coefficient of the thermal expansion (CTE) values first decreased, then increased and finally tended to flatten. When the content of TiO2 increased to 6%, the CTE value decreased to 9.15×10-6/K, reached the lowest value. When the content of TiO2 increased to 10%, the CTE value reached highest value 13.90×10-6/K.
The Preparation of Calcium Carbonate Modified High Water-Absorbing Resin
Authors: Shi Qi , Meng Qing Luo , Wang Nong
Published: October 2014

The poly (sodium acrylate/acrylic acid) water-absorbing resin was prepared by aqueous solution polymerization with acrylic acid (AA) as the monomer, calcium carbonate as the modified additives, N, N-methylene double acrylamide (NMBA) as cross-linking agent, ammonium persulfate (APS)/sodium sulfite oxidation reduction type initiator. It was found that the adsorption performance of absorbent resin modified by calcium carbonate strengthened obviously. Orthogonal and single factor experiment were used to establish the optimum parameters related to the product preparation. The best process conditions on water-absorbing properties of the modified resin was obtained. Using 150mL acrylic acid as a benchmark, the result show the optimum process conditions: the reaction temperature is 55°C, the mass fraction of monomer is 20%, the neutralization degree is 45%, modified additive dosage is 10 g, the dosage of cross-linking agent is 0.1%, and the initiator dosage is 2.0%, respectively. After made under the optimum process conditions, the water-absorbing rate of the modified resin was 676.6 times the dry weight.
Synthesis of Cu Nanowires by the Self-Assembly Growth Process
Authors: Li Bo , Li Min , Jing Mao Xiang , Wang Zhou , Shen Xiang Qian
Published: October 2014

The ultralong copper nanowires (Cu NWs) with diameter of 90±10 nm and length over 20 μm were synthesized by the self-assembly growth process, in which the copper ions were reduced with hydrazine in an aqueous solution containing NaOH and ethylenediamine (EDA). The prepared Cu NWs were characterized by XRD, SEM and TEM. The results indicate that the ultralong Cu NWs product almost containing no particles can be obtained at 80 °C for 1 h with a proper concentration of EDA. During the growth of Cu NWs, as the EDA moleculars are possibly preferentially absorbed onto the crystal plane of (110), the gowth of Cu NW will be oriented along the crystal plane of (111).
Factors Influencing Dielectric Properties of A-171@CCTO/PVDF Composite Films
Authors: Zhai Jian Wen , Wang Ya Jun , Li Fu Yang , Feng Chang Gen
Published: October 2014

Current research efforts toward achieving ceramic/polymer composites which fulfill the balance between sufficiently high dielectric constant (ε) and low dielectric loss (tanδ) are presented. In this paper, ceramic/polymer composite films made of CaCu3Ti4O12(CCTO) powder as filler, which is modified by silane coupling agent vinyltrimethoxysilane (A-171), and polyvinylidene fluoride (PVDF) copolymer as matrix were prepared by solution casting method. The morphology and dielectric properties (DP) were studied by transmission electron microscopy (TEM) and impedance analyzer. The effect of pH and ethanol concentration on the dielectric properties of A-171@CCTO/PVDF were studied. The results show that constant could reach 54.17 and loss 0.05 when mass fraction of A-171 is 0.4% at 1 kHz. pH=4 and using anhydrous ethanol are the optimal conditions.
Preparation of Heat-Resistant Enameled Wire Coating of Fluorinated Poly (Ether Ether Ketone) and Properties
Authors: Gui Ting , Zhao Yun , Jiao Qing Ze , Li Han Sheng , Wu Qin
Published: October 2014

The soluble poly (ether ether ketone) (PEEK) containing trifluoromethyl group (FPEEK) was prepared by nucleophilic polycondensation reaction of 4, 4'-difluorobenzophenone and 4, 4′-(hexafluoroisopropylidene) diphenol in the presence of an excess of anhydrous K2CO3 with tetramethylene sulfone as the solvent. The structure and thermal stability of FPEEK were studied by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, X-ray diffractometer and thermogravimetric analyzer. The solubility of FPEEK was also investigated using different organic solvents. Then the solution of FPEEK in N, N-dimethylformamide (DMF) was applied to prepare insulating coating. The mechanical properties of the coating were tested. The results show that FPEEK is soluble in common organic solvents such as chloroform, tetrahydrofuran and DMF. FPEEK shows high thermal stability with the initial degradation temperature of 536 °C in nitrogen. The insulating coatings of FPEEK exhibit the good adhesion, flexibility and impact resistance.
Experiment on the Attenuation Characteristics of Shock Wave Interacting with Open and Closed Foam
Authors: Wang Jian , Wang Bao Gui , Tao Gang
Published: October 2014

For understanding the dynamic behavior of open and closed foam subject to a shock wave, this paper through experiments, to gain a deeper understanding of the incidence, reflection and transmission of a shock wave when it interacted with cellular foam. Moreover, by analyzing the loss of the peak overpressure and positive impulse, we were able to respectively know the positive impulse of the incidence, reflection and transmission shock wave. The experimental results indicated that the attenuation capability for foam to the shock wave was caused by the internal friction and deformation of solid phase, which would absorb the energy of the shock wave. From the results we gain an understanding that the mechanical phenomenon of open foam to shock wave are not fully consistent with those of closed foam , while the attenuation of open foam to shock wave is more effective than that of closed foam.
Study on Optical and Thermal Properties of Low-E Glass
Authors: Meng De Ming , Li Bing Qian , Zeng Meng Yan , Li Chen Hui , Dai Ru Cheng
Published: October 2014

A coating methods and the structure of Low-E glass are described in this paper, and the optical and thermal properties of the samples are analyzed as well. The results show that the Low-E glass has a high transmittance in visible region and with a higher reflectance in middle-infrared band and far-infrared band. It can effectively prevent the heat through the glass. Therefore, Low-E glass can save energy by letting enough sunlight into the room and by impeding the heat through the glass effectively.
Multiway Principal Component Analysis for Smartphone Captured Image of Colloidal Gold Strip
Authors: Zhou Lei , Liu Yan Zhen , Zhang Chao
Published: October 2014

Lateral flow test kit has become a popular device for immunoassay of biologically important molecules. Colloidal gold strip has been commercially available for point-of-care clinical testing at hospital or simply at home for self-testing. A method for reading the reaction results of colloidal gold strip assays is proposed. The RGB (red-green-blue) image of a reacted strip is captured by smartphone under natural-light illumination. The two-dimensional grayscale image of each color channel is transformed into nine images by spatially shifting the image in eight adjacent directions. After all three color channel images are transformed, an array including twenty-seven images is constructed. Multiway principle component analysis is then used to the array, extracting texture information of the original image. When the extracted texture is added back to the original image, color of control line and test line regions can be effectively enhanced for reading by naked eyes.
Application of the Method Basing on Engineering Knowledge and Experience for Adding the Hexapod Design Process
Authors: Ociepka Piotr , Herbuś Krzysztof , Gwiazda Aleksander
Published: October 2014

The paper presents the method basing on engineering knowledge and experience for aiding the design process of hexapods. The method proposed by the authors uses the architecture of a hybrid system, which combines an advisory system and the CBR (Case Based Reasoning) method. The paper includes the formalized description of the developed method and presents the system functioning on the example of the design process of hexapods.
Microstructure and Mechanical Properties of FeNiCrCuAl High Entropy Alloys
Authors: Buluc Gheorghe , Florea Iulia , Bălţătescu Oana , Roman Costel , Carcea Ioan
Published: October 2014

This paper presents the microstructure and the mechanical properties of FeNiCrCuAl high entropy alloys. The microstructure and mechanical properties of the annealed FeNiCrCuAl high entropy alloys were investigated using scanning electron microscopy, and X-ray diffraction. High entropy alloys have been known as a new type of materials and have been defined as having five or more principal elements, each one having a concentration between 5 and 35 at.%. Previous researches show that HEAs can be processed to form simple solid solution structures instead of intermetallics and other complicated compounds. This phenomenon is commonly attributed to the high configurational entropy in the solid solution state of HEAs. Furthermore, HEAs have also exhibited interesting properties such as high hardness and high strength, good thermal stability outstanding wear and oxidation resistance which offer great potential for engineering applications. The HEA systems explored in the past decade show that metallic elements are the most commonly used, e.g. Al, Cr, Fe, Co, Ni, Cu,Ti, etc. A wide range of HEAs exhibit high hardness, high strength, distinctive electrical and magnetic properties, high-temperature softening resistance, as well as favorable combination of compression strength and ductility. This combination of properties and the particular structures of HEAs are attractive for a number of potential engineering applications.
Performance Management in Entrepreneurial Contexts
Authors: Nacu Cosmin Mihai , Avasilcăi Silvia
Published: October 2014

Using organizational performance management that is validated and used in active companies, this research aims to study business performance management in entrepreneurial frameworks. This study presents a conceptual approach based on some theories founded on the organizational performance management as a process, but adapted to the context of entrepreneurship. It is proposed the conceptual analysis and submitting the verification of the formulated hypotheses. An entrepreneurial framework is defined by some factors such as: entrepreneur, along with his personal and professional characteristics, who is the main actor of the so-called entrepreneurial process; business idea that entrepreneur wants to turn it into profitable business; market opportunity, which demonstrates that the business idea is valid, has novelty and can be fructified and developed; business plan, that needs to be well prepared in a very detailed manner and containing long run strategies; business start-up resources, including time resources allocated to implement the business plan, physical resources, information, financial and human resources; the environment where the business will be active; technology needed to develop the business activity. To study more closely the issue of performance management in entrepreneurial contexts, will be defined entrepreneurial performance management as a process, which can lead to the success rate of a business idea and to the rate of business sustainability. To perform this study it has been proposed a case study where an entrepreneur wants to develop a business in renewable energy, and more specifically, the development of a solar power plant that transforms solar energy into electricity, which then it’s been introduced into the national grid of electricity supply. So in this research will be studied the entire process by which the real business appears and a variant of the case that the solar power plant could be built in Romania and will be proposed a detailed system of performance indicators, specific to the entrepreneurial framework. Using a research methodology based on case study, this research has as a central objective, to define the entrepreneurial performance management through a set of specific performance indicators, which can then be used in practice, by entrepreneurs who want to start a new business in renewable energy.
Influence of Hot-Working Conditions on a Structure of X11MnSiAl17-1-3 Steel
Authors: Dobrzański Leszek Adam , Czaja Małgorzata , Borek Wojciech , Labisz Krzysztof , Tański Tomasz
Published: October 2014

The investigations are focused on high-manganese austenitic steels used for reinforcing elements of car body. The purpose of this work was to examine the influence of thermo-mechanical treatment workout using Gleeble simulator and LPS module for semi-industrial hot-rolling on the structure and transformations occurring during cold deformations. Thermo-mechanical treatment consists of four passovers with a planned strain rate of about 20%. There were three variants of cooling after thermo-mechanical treatment: cooling in water, natural air-cooling and cooling in water after isothermal holding in the temperature of last deformation 850°C for 30 s. Structural observation were carried on LEICA MEF4A light microscope, analysis of the chemical composition were made with XPert PRO diffractometer, and the results were analyzed with OriginLab. It was found that the high-manganese austenitic X11MnSiAl7-1-3 steel after thermo-mechanical treatment on Gleeble simulator is characterized by dynamically recrystallized structure. In intervals time between each compression metadynamic and static recrystallization take place. After hot-rolling these steels has austenitic structure with dynamically recovered grains and with small metadynamically and statically recrystallized grains that are located on a border of elongated grains of austenite.
Secondary Radiation in Color Optical Filter Glasses by the Action of Plasma
Authors: Hirbu Arefa , Topala Pavel , Ojegov Alexandr
Published: October 2014

This paper presents the results of experimental investigations and theoretical analysis of secondary physical phenomena that occur at interaction of electrical discharges in impulse (EDI) plasma radiation with color optical filter glasses. It was established that infrared filters (of type IKS) emit a violet secondary radiation, and dark filter (of type TS) emits a green secondary radiation. Detected phenomena can be explained by secondary radiation emission due to multi-photonic excitation of SiO2 molecules and direct-inverse translating from one energy level to another. One of the resonance oscillatory levels (of the absorption bands) for molecules of SiO2 is 780 cm-1. Thus, for infrared filters the number of absorbed infrared photons is 33, and for dark glasses is 24. In this case, the wave length of secondary radiation is 388.5 nm (violet color) and 534.2 nm (green color) respectfully. This phenomenon can be applied in construction of equipment functioning based on monochromatic light radiation.
Microstructural Characterization of Silicide Coatings on Mo and TZM Alloy
Authors: Moskal Grzegorz , Swadźba Lucjan , Supernak Wacław , Mikuśkiewicz Marta , Mościcki Adrian , Jabłońska Magdalena , Niemiec Dawid , Kałamarz Piotr , Staszewski Marek , Wrona Adriana , Osadnik Małgorzata
Published: October 2014

Characterization of microstructure of silicide coatings obtained during diffusion process of pack cementation type was showed in this article. The basic materials were pure Mo sheet and TZM molybdenum alloys as well. The coatings were deposited in out of pack process with three different times of exposure. The temperature of deposition process was constant. In first step the phases compositions of coatings was described by XRD analysis. In each cases the MoSi2 phase was obtained on top surface of the coatings. The morphology of the coatings was very similar as well. All types of coatings were characterized by network of cracks on top surface of the coatings. There was no influence of depositions time on phases constituent and coatings topography. LM and SEM analysis revealed that internal coatings morphology was very similar in all cases. Basic differences was related to the thickness of coatings. All coatings were good quality without deep cracks. Microstructure was a columnar-like type without pores and voids.
Decreasing the Adhesion Effect of Surfaces Using Graphite Pellicle Deposition through Electric Discharges in Pulse
Authors: Topala Pavel , Besliu Vitalie , Marin Laurentiu
Published: October 2014

The paper aims at studying the phenomenon of adhesion between the graphite pellicles deposited through electric discharges in pulse (EDI) with metal surfaces subjected to processing on the one hand and on the other hand the adhesion of this pellicle with a polyurethane adhesive. Experimental research has shown that, when the surfaces are not treated, the shear occurs in the adhesive, when the test pieces are covered with graphite pellicles the shear occurs on the surface that separates the pellicle from the adhesive. It has been stated experimentally that graphite pellicles deposited through electric discharges in pulse decrease the adhesion between the mating surfaces by at least 40% compared to the not treated surfaces.
The Study of Microstructure of the MgCa Alloys in their Use in Biodegradable Orthopedic Implants
Authors: Crimu Carmen , Antoniac Iulian , Focșăneanu Sergiu Ciprian , Cristea Diana Pitul , Istrate Bogdan , Munteanu Corneliu , Earar Kamel
Published: October 2014

The need for structural materials in temporary implant applications has grown in the recent years; materials that provide short – term structural support and which can be reabsorbed into the body after healing are being sought. These are materials that are biocompatible and biodegradable. These constitute a novel class of bioactive biomaterials which are expected to support the healing process of a diseased tissue and to degrade thereafter. Magnesium alloys attracted great attention as a new kind of degradable biomaterial. Mg shows great promise as a potential biocompat
ible and biodegradable material
in biomedical applications where it has gained the interest of researchers in the field. Biodegradable and bioabsorbable magnesium – based alloys provide a number of benefits over traditional permanent implants. There are however some disadvantages to the use of Mg alloys, one of the most critical being the release of hydrogen and alkalinization resulted from the corrosion of Mg. In connection to these drawbacks, a possible solution could be finding alloying elements which would contribute to the reduction of the corrosion rate in the human body. Studies show that a promising alloy for Mg, could be Calcium - a major component of the human bone and also an essential element in the chemical composition of cells.
The present paper shall focus on the elaboration of Mg-Ca alloys, respectively
Mg0,63Ca to
Mg0,8
5
Ca, in the form of bars. These bars were obtained by cast in an inert atmosphere in the presence of argon, in order to be analyzed as biodegradable orthopedic implants. The structure of the alloy has been studied through SEM analyses, X-Ray diffraction, and EDAX to determine the chemical composition, as well as the distribution of elements in the structure. The main desiderate is finding an alloy which would have a minimum healing period postsurgery, pathophysiology and toxicology and a promising degradation behavior.
Researches Concerning the Improving of the Cutting Inserts Durability Using Titanium Deposition
Authors: Bădănac Ana , Popa Scurtu Ramona , Bosoancă Gheorghe , Hușanu Valerică , Popa Sorin
Published: October 2014

It is known that in the cutting processes, due to the parameters variation of the working regimes, to the unevenness of the cutting depth, to the physico-mechanical characteristics of the processed material, to the existence or nonexistence of the coolant oiling, can appear more or less an accentuated wear of the cutting tools. All this factors have a dominant and negative influence on the durability, fact that impose being necessary taking into account some measures to increase the values of the cutting tools and/or of theirs cutting plates durability. In this sense are known various coating by deposition in vacuum researches (vacuum thermal evaporation and condensation from the vapor phase, ionic plating, vapour chemical deposition at low pressure, and so on) of some different filler materials, in thin layers, having protection role for the cutting plates, to increase the edge hardness to the superficial layer and of the tool locating and clearance surfaces and respectively, of their wear resistance. For this purpose, the authors propose to improve cutting tools durability using the deposition method by ionic plating in vacuum (PVD) of the thin titanium layers, following the cutting tools behavior in operation treated in this way. It was so studied the metal carbide cutting plates wear variation, coated with a titanium thin layer and it was determinated the cutting plates durability increasing, in comparison with those untreated. This research is usefull for predicting the lifetime of the cutting tools and/or of theirs cutting plates durability, after the titanium thin layer application, with a significant cost reduction.
Numerical Analysis of the Material Thickness Variation during Forming Process of Conical Mini-Parts
Authors: Teaca Robert Stefanut , Brabie Gheorghe
Published: October 2014

Due to the trend of miniaturization on electrical devices, medical devices, and energy, etc., the need for micro and mini metal parts is increasing at a tremendous rate. In order to realize the potential of the mini-parts and take advantages from the mini-forming process, innovative modifications of the forming process must be developed. These modifications are particularly important with respect to the mini-parts forming, which offers an excellent opportunity to produce high accurate mini parts and to reduce manufacturing costs and time. However, severe modifications of the material thickness occur during forming of mini-parts. This paper presents a study concerning the material thickness variation during forming process of mini-parts. The main objective is to understand the material behaviour during forming of mini-parts. The material used in this analysis is copper - zinc alloy with anisotropic properties. During forming process of conical mini-parts, the material become very thin around the punch radius and become thicker at the upper end of the part. This phenomenon cause forming problems such: material fracture, wrinkling, part diameter variation, springback etc. There are multiple factors that affect the material thickness variation during forming process as: side wall angle, friction coefficient, punch radius, and punch speed. The Dynaform 5.9.1 software was used to simulate the forming process. The part obtained after each simulation was analyzed and measured to quantify material thickness variation on the final conical mini-part. To analyze the behaviour of the material during deep drawing process the obtained results for different conical mini-parts were compared. In the final part of this paper some conclusions regarding the material thickness variation during forming of conical mini-parts are presented.
Numerical Analysis of the Residual Stresses Caused by Forming Process in Case of Conical Mini-Parts
Authors: Teaca Robert Stefanut , Brabie Gheorghe
Published: October 2014

The research presented in this paper refers to numerical simulation related to deep drawing of conical mini-parts having different geometries as a function of side wall angle. The mini-parts are made from copper zinc alloy, having the thickness of 0.2 mm. Very important concerns in cold forming of conical mini-parts are the residual stresses due to their influence on the final shape of the part. During the forming process, due to different angles of the side wall, the residual stresses vary. After the mini-part is removed from the forming tools, the residual stresses modify the geometry of the part, causing dimensional errors. The residual stresses decrease the ability of the designer to draw some specific shapes because it may create forming problems such as wrinkling, tearing, and uncontrollable springback. The Dynaform 5.9.1 software was used to simulate the forming process. The part obtained after each simulation was analyzed and measured to quantify the effect of the residual stresses on the final geometry of part. All the parameters were maintained constant excepting the side wall angle. The obtained results for different side wall angles were compared to realize the behaviour of the conical mini-parts during and after deep drawing process.
Integrated System for Monitoring the Tool State Using Temperature Measuring by Natural Thermocouple Method
Authors: Inţă Marinela , Muntean Achim
Published: October 2014

The intensive developments of intelligent manufacturing systems in the last decades open the large possibilities of more accurate monitoring of the metal cutting process. One of the most important factors of the process is the tool state given by the rate of the tool wear, which is the result of a lot of influences of almost all cutting parameters. The modern tool monitoring systems relieved that the accuracy of the results increases when using a combination of surveyed signals such as: vibrations, power consumption, acoustic emission, forces or tool temperature. Combining the output signals in a monitoring function using the neural network method gives the best results when using on-line monitoring. Considering the tool temperature as an important factor in the tool wear process and adding it to the acoustic emission and force measuring the accuracy of the results seems to improve significantly. The present paper describes an integrated monitoring system with integration of the cutting temperature, the calibration device for work piece-tool thermocouple, and the block diagram for on-line survey measuring using LabView platform.
A Study Concerning the Workpiece Profile after Grinding Process of Precessional Gear Wheels
Authors: Casian Maxim , Mazuru Sergiu
Published: October 2014

In this paper we present a study of issues related for determination the real profile and the theoretical one of the precessional gear wheels. In the research process of the precessional gears profile appeared the problem of finding the geometrical error between fabricated profile and the ideal one after grinding process. The cause of the errors has technological and constructive nature. Processing technology of these specific gear wheels is one that still has many unknowns, therefore will be researched the part that is related to the occurrence of deviations from the ideal profile. The manufacturing of processing device and its elements also lead to geometric deviation of the profile, which will lead to adverse effects during operation. Measurement of manufactured profile using special equipment would involve high costs of time and money, therefore will be used computational methods and the statistic-mathematical method. The computational method is to find a better methodology to transform a file obtained from 3D scan (precessional gear wheel), which can be used only as a copy, into a file with functional extension. Such a conversion is very important to make especially for objects with complicated geometry such as precessional wheel profile. Transformation will result in surfaces and geometric objects that can be manipulated and compared to each other, with the aim of find deviations between ideal 3D models and the real ones. The methodology is relative simple: the triangular surfaces which form the shell of object should be approximated by flat, cylindrical, conical, etc. surfaces interlinked and filling the empty space between them with material. Once the scanned real object is transformed into a functional virtual file, it can not only be compared with the ideal model but also modified at the discretion of the user. Also we can find the coordinates of points which form the wheel contour line, which can be analyze and interpolate to obtain a mean value of scanned profile. Following the analysis of a profile obtaining was observed a small error of inclination of the gear teeth, due to the technological process. This methodology can be used to finding geometric errors also for other objects, gears etc.
Theoretical and Experimental Aspects Concerning Elastic Behavior in the Grinding Technological System
Authors: Mazuru Sergiu , Casian Maxim
Published: October 2014

In this paper will be treated the problem of strains and stresses within the connections and elements from the grinding technological system. These system deformations can lead to positive or negative effects. Main negative effects will be occurrence of processing errors on the part profile, but also the excessive tension from system elements. Cause of processing errors and the low safety due of the system rigidity must be sought in its joints between parts, stiffness of moving pieces, low number and reduced rigidity of parts used to assembling (bolts, cotter joints, pins). Elastic properties of the assembly are modeled by the inserted connections with specific characteristics. The elastic deformation of the work piece must be taken into account, besides the elastic behavior of the device which appears in manufacturing process. A very important aspect in the study of elastic behavior of the whole system is how the abrasive tool interacts with the work piece, namely the displacement of contact zone. Contact stresses lead to a deformation of the grinding wheel and the work piece, and as a result the work piece loses from precision of tooth profile. The rigidity of system can be characterized by two aspects, one static and one dynamic and we will describe both aspects using CAE simulations and classical mathematical models. It will be presented some results of numerical simulation of the stiffness of gear grinding system using finite element method (FEM). The elastic dynamic model was design using the forces of inertia and gravity that occurs during grinding process. Also by permanent pursuing of the technological forces variation during the grinding process will be sought the dynamic deformation of the system. The study its concentrated around the low stiffness of components inside the system, in order to find errors that may affect the precision on the horizontal, vertical and rotational direction of technological system elements. Since through this analysis it tried to find how the forces influence on the ETS stiffness, it will present numerical values of the system displacements and stress distribution. Knowing the direction, sense and numerical values of these errors can be made interpretation of the results, namely the removal of these consequences.
Drying Kinetic Simulation of Clay Tiles Made from the Raw Material Having Less Clay Fraction
Authors: Vasić Miloš , Radojević Zagorka
Published: October 2014

In order to describe the internal moisture rate and to take all different mechanisms of moisture movement into account, it is suitable to use effective diffusivity as a measure of moisture rate, irrespectively of the mechanisms really involved. This means that all different mechanisms and driving forces for internal moisture transport are lumped together and introduced into effective moisture diffusivity. Hence, diffusion equations are retained and reused with the effective diffusivity coefficient as a measuring parameter of internal moisture ratio. In our previous studies we have presented the calculation method which assumed constant diffusivity. The next goal was to estimate effective diffusivity at various moisture contents, in a real case of non-linear drying curves, and to predict drying kinetic. In our last study we have developed a model for determination of the variable effective diffusivity and identification of the exact transition points between possible drying mechanisms. In this paper we have tried to develop more accurate tool for determination of time dependent effective moisture diffusivity. An analytical model and computing procedure were developed to evaluate mass transfer properties and describe drying kinetic of clay tiles having less clay fraction. The proposed procedure was validated with experimental drying data. Presented results have demonstrated that the proposed dying model can be applied for the accurate description of experimental drying kinetics and a reliable estimation of effective diffusivity.
Determination of the Optimal Blank Diameter in the Case of Mini Deep Drawing by Applying the Fuzzy Logic and Taguchi Methods
Authors: Brabie Gheorghe , Chirita Bogdan , Costache Elena , Teaca Stefan
Published: October 2014

An important problem in obtaining mini drawn parts with high precision is represented by the blank geometry. Utilization of a blank with optimal shape and dimensions leads to the following benefits: improves the accuracy of the drawn parts and determine the costs reduction due to reduced material consumption and cost, lower number of technologic operations, shorter manufacturing times etc. An adequate blank prevents the following effects on drawn part: avoids the part fracture, conducts to a uniform distribution of the material thickness in drawn part and reduces the blank holder force required by the drawing process. The present paper analyses the results of investigations made by simulation and experiment concerning the establishment of the optimal blank diameter in the case of mini cylindrical drawn parts made from aluminium sheets. The optimal blank diameter was determined by applying the Fuzzy Logic and Taguchi methods.
Generation of Square Cavity Using Planetary EDM
Authors: Mathai Vishal John , Dave Harshit K. , Desai Keyur P.
Published: October 2014

The design and manufacturing of complex shaped 3D features have a wide range of applications in todays manufacturing industries. With machining of hard materials continues to attract much interest in this field, EDM remains an indispensable process to carry out this purpose despite its limitations compared to conventional machining processes in terms of material removal rate and surface quality. Many process improvement techniques have been reported by researchers to overcome these limitations and out of them, incorporation of tool electrode kinematics is observed to have a significant effect. In the present investigation, an attempt has been made to study the effectiveness of two different tool motions in the generation of non-circular cavities. Tool electrode is moved on planetary and diagonal paths during this study. Effects of various electrical and non-electrical parameters on EDM responses have been studied. Current, pulse ON time and voltage are considered as the electrical parameters while tool kinematics parameters like tool path offset and scanning speed have been selected as the non-electrical parameters. Experiments have been carried out the study the effect of tool movement on planetary and diagonal path on different response characteristics viz. Material removal rateand Wear Ratio. It has been observed that planetary motion is a better strategy than diagonal motion for the generation of non-circular cavities in terms of achievement of the response characteristics. The results observed are critically discussed.
Thermal Embossing Method for Glass Recycling
Authors: Neagu-Cogălniceanu Camelia , Neagu-Cogălniceanu Irinel
Published: October 2014

Over the past years the target for waste recovery/ recycling has significantly increased in Romania, in according with the EU Directives. Nowadays, the competitive contexts of the current market lead the manufacturers to obtain novel and custom-made products using new technologies and quality raw materials. Such resources can be consisting of low-cost waste/by-products and in the processes of converting them into value-added products. On the other hand, the necessity for recycling waste is important under the strict European legislation. Regarding glass, the key sources of waste are container/ packaging glass, flat glass, electric and electronic equipments, domestic glass, E-glass, etc. According with source, waste glass can be: pre-and post-consumer waste glass. Now many recycling processes have been studied, developed and applied in industry. The major challenge is represented by creating of innovative and sustainable technologies and making it suitable. But recycling of glass is technologically more complicated than other waste (for example: paper). In case of glass, the most sustainable route is to use it for re-melting processes and obtaining a new glass. Glass is 100% recyclable but not all waste/cullet can be used for the manufacturing of any type of glass, due different chemical composition and the prohibitive shipping costs from collection points to glass factory. In this study, authors paid attention to the recycling process of soda-lime glass (post-industrial flat glass) and proposed the thermal embossing technique of glass, using glass slumping process, in order to obtain decorative products with aesthetic impact and functional role. An input image is prepared by applying different enhancement techniques, adjusting contrast, transferring into grayscale image in 256 shades of gray. The result image is transferred in Computer Aided Manufacture (CAM) software to refine the surface geometries and to obtain with rapid tooling the mould for glass. The method used for tooling fabrication consists of machining a block of suitable material with a Computer Numerical Controlled (CNC) machine which is known as a subtractive method. The next stage consists in applying of the heat treatment, using an electrical furnace. The major advantages of the embossing method for converting waste glass in value-added products is represented in the fact of use reduced energy comparing with the classic route of re-melting, possibility of obtaining bespoke products, ready to use in architectural and decorative fields. In addition, environmental benefits that results from processing waste glass are the reducing the raw materials (virgin) and the CO2 emissions.
Studies Regarding the Influence of Loading Force on the Wear Intensity in Case of Polymeric Composite Materials Reinforced with Short Carbon Fibers
Authors: Caliman Radu
Published: October 2014

This paper presents a study of the wearing behaviour of polymeric composite materials reinforced with short carbon fibres. Reinforces carbon fiber materials are more effective if refer to specific properties per unit volume compared to conventional isotropic materials. The composite materials used in this research work are obtained combining epoxy with short carbon fibres with titanium carbide and tantalum carbide in order to investigate the wearing intensity of the obtained composites. Varying the percent of epoxy from 29,35% to 43,92% and the percent of short carbon fibres from 35,43% to 53,70%, two different composite materials are obtained and tested. Wearing intensity tests are carried out, at room temperature, in dry conditions, on a pin-on-disc machine. The friction coefficient was measured maintaining constant the rotational speed (14 m/s) and time (120s) and varying the pin-on-disc pressing force: 4, 8 and 12 daN. The pressing load had different effects on the wearing behaviour of the composite coating in dry friction condition. With low percent of epoxy and high percent of carbon fibers the wearing intensity is touching the highest value and gradually decreases with the increasing load, while in low percent of carbon fibers the wearing intensity became larger gradually along with the load increasing.