bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of Ceramic Crock Structure Made of Technogenic Raw Materials with Vanadium Component
Authors: Stolboushkin Andrey , Fomin Alexey , Stolboushkina Oxana
Published: April 2015

The present study provides chemical, granulometric and mineral compounds of raw materials of ceramic charge. The ceramic materials structure made of slimy part of iron ore wastes with corrective additions has been observed by the SEM, petrographic methods and spectral analysis. The introduction of corrective additions leads to formation of crock with evident glass ceramic structure describable by porous texture. Pore space is completely or partially filled with cryptocrystalline substance. It has been determined vanadium component intensifies sintering processes during the firing and leads to formation of new mineral phases. This increases the strength of ceramics.
Hardening of Metallurgical Machinery Components by Facing with Heatproof, Hard Steels and Low Temperature Pre-Heating
Authors: Malushin N.N. , Valuev D.V. , Osetkovsky V.L. , Valueva A.V. , Serikbol A.
Published: April 2015

The technology of metallurgical machinery components facing with heatproof, hard steels and low temperature pre-heating is developed, and enables producing faced metal without cracks but in condition similar to the quenched one.
Physical-Mechanical Properties of Corundum-Zirconium Ceramic Obtained by the Technology of Radial Magnetoimpulse Pressing
Authors: Akarachkin S.V. , Sivkov A.A , Ivashutenko Aleksander S. , Martyushev N.V.
Published: April 2015

The paper presents comparative studies of physical-mechanical properties of long-measured/elongated corundum-zirconium ceramic with different phase ration, manufactured with the use of the radial magnetoimpulse press. The optimal mode of pressing of ultra-dispersed powders was developed, where the amplitude of magnetoimpulse pressure is 1.14 GPа at acceleration time-120 mcs. We obtained the corundum-zirconium ceramic with the grain size 0.35-0.5 μm and the coherent-scattering regions of 0.050-0.120 μm, possessing microhardness 10.6-12.9 GPа and crack-resistance 5.5-7.8 MPа·m1/2.
Experimental Studies of Counter Vortex Flows Modeling
Authors: Churin Pavel , Kapustin Sergei , Orehov Genrih , Poddaeva Olga
Published: April 2015

The article investigates the counter-vortex flow, one of the most complex spatial nonuniform liquid and gas flows. Counter-vortex phenomenon implies an interaction of two or more wake coaxial circular-longitudinal lines twisted in opposite directions. The relevance of the research issue has determined the desirability of further research and application of unique hydraulic devices in the new situation based on the effect of the interaction of coaxial oppositely swirling flows of water in a circular pipe.
Gas Injection into Porous Reservoir Partly Saturated by Water
Authors: Khasanov М.K.
Published: April 2015

Specific features of formation of gas hydrates due to injection of a gas into a porous medium initially filled by a gas and water are considered. Self-similar solutions to the planar one-dimensional problem are constructed, which give the distribution of main bed characteristics. The influence of the initial parameters of the porous medium and the intensity of the gas injection on the dynamics of the processes of hydrate formation is studied. The existence of solutions is demonstrated, which predict gas hydrate formation both on the frontal surface and in the volume zone. The critical conditions that separate the different modes of hydrate formation are found.
Simulation of a Flexible Mirror Performance in the Problem of Adaptive Compensation for Aberrations in an Optical System
Authors: Kanev Feodor , Rytchkov Dmitry , Makenova Nailia
Published: April 2015

Results are presented of numerical simulation of a laser system performance with account of limitations induced by a flexible mirror. The method of finite elements was used to calculate deformations of a mirror reflecting surface. Solution to the parabolic equation describing propagation of a laser beam in the turbulent atmosphere and effects of its backscattering was obtained on the base of the splitting algorithm. It was shown that effectiveness of the adaptive system is not influenced considerably by restrictions characteristic to the mirror.
Dynamic Susceptibility of a System
Authors: Gerget Olga M. , Kochegurov Vladimir A. , Titarenko Ekaterina Y.
Published: April 2015

This article introduces research results by members of the Chair for Applied Mathematics, Tomsk Polytechnic University, who are also members of the scientific school of Development of Physical Foundations of Software for Energetic and Information Representation of Functional Characteristics of an Organism for Medical and Preventive Tasks. In this article development of a universal mathematical apparatus to solve the tasks of monitoring, adaptation and regulation is described. To evaluate severity of change in a state vector, which describes mutual dynamic interactions among state variables of a system, geometric means of the vector and its deviation rate are used. Basic principles of assessment of dynamic susceptibility in systems are given. Coefficients that represent deviation of state variables from equilibrium values are described. Ability of regulatory mechanisms of a system to assure its stable functioning is explained.
Geometric Model of the Interaction of the Grinding Wheel and Workpiece during Surface Grinding with the Periphery of a Straight Wheel
Authors: Dyakonov Aleksandr A. , Shipulin Leonid V.
Published: April 2015

Results of development of geometrical model of a shaping of a polished surface at surface grinding by the periphery of a wheel are presented in article. The developed model allows to predict a roughness of the processed surface depending on basic parameters of operation: speeds of rotation of the tool and translational motion of workpiece, wheel parameters – granularity and structure, depth of cutting and other parameters. Results of experimental check of the developed model are given in article.
Tessellation Methods for Modeling the Material Structure
Authors: Burtseva Larysa , Werner Frank , Valdes Benjamin , Pestryakov Alexey , Romero Rainier , Petranovskii Vitalii
Published: April 2015

Tessellation methods are a relatively new approach for modeling the structure of a material. In this paper, such structures are interpreted as sphere packing models, where molecules and atoms represent spheres of equal or different size. Based on the review of the literature, it is shown that the tessellation approach is a powerful method for modeling and simulating such structures with desirable metric and topological properties. Two basic tessellation methods are considered more in detail: the Delaunay tessellation and the Voronoi diagram in Laguerre geometry, as well as some of their generalizations. The principal concepts of both tessellation methods are briefly explained for a better understanding of the application details. It is noted that packing models created by tessellation methods are not based on the use of the gravity camp effect, which is a difference to numerical and mathematic programming modeling approaches. Therefore, tessellation methods permit the development of structures without taking into account the gravitation, what is important for modeling the structure on the microscopic and nano levels, where the influence of the gravitation is studied insufficiently. A review of the related literature is given, focusing on the details of the tessellation method and the particle size distribution.
Numerical Study of Shock Wave Interaction with Protective Stopping with Regard to the Type of its Setting
Authors: Baganina A.E. , Paleev D.Y. , Beglyakov V.Yu.
Published: April 2015

The paper presents a numerical study of the interaction of a shock wave with a protective stopping. It addresses the effect of the type of setting on dangerous stresses emergences under the explosion. The types of setting are evaluated depending on the nature of the load on the sopping. Heavy concrete of B15 grade was taken as the material for evaluation.
Prospects for Further Rock Cutting Mechanisms Development
Authors: Novoseltseva M.B. , Pashkov Evgeny N.
Published: April 2015

In this research power rock cutting mechanisms are considered. Impact and vibratory impact mechanisms are presented, their design characteristics are given. The new peenless power pulse hydraulic mechanism is considered, its operating principle is described, and the schematic diagram is provided. The new system can be used at building of the new rock-drilling machines with a hydraulic actuator for the intensification of the process of rocks destruction.
Stressed-Strain State of Multi Layer Foil under One-Axis Tension
Authors: Demidov V.N. , Knyazeva Anna G.
Published: April 2015

Multilayer protective materials and coatings attract attention last years because the possibility appears to obtain unique properties of materials due to combination of properties and sizes of layers. In his paper analytical solution is constructed for the problem on multilayer foil tension. It is assumed that stress and strain tensor components depend on one space coordinate in the axis direction perpendicular to layers and generalized plane stressed state is realized. Interesting effect is detected for two-layer material: thickness of the coating exists when one of diagonal stress tensor components is minimal, that ensure minimal break in the corresponding stresses in interface. This effect is observed previously experimentally by many authors. However, other diagonal component of stress tensor has maximal value for other value of coating thickness. The positions of the maximal and minimal values of stresses and breaks depend on combination of properties and thicknesses of layers.
The Method of the Centerless Roundness Measuring with Corrective Adjustment
Authors: Zakharov Оleg V. , Korolev Albert V. , Korolev Andrew A. , Kochetkov Andrew V.
Published: April 2015

A new method of the data measurement and processing for the centerless roundness measuring of components with the use of corrective adjustment is proposed. There are scientific explanations for mathematical simulation which includes numerical methods and harmonic analysis and also considers the change of the contact points of the product and prism faces during rotation. The methodical error and the evaluation of the centerless roundness measurements are determined according to the practical measurements and the model analysis.
Synthesis of Three-Dimensional Models from Drawings Based on Spectral Graph Theory
Authors: Zakharov Aleksey , Zhiznyakov Arkady
Published: April 2015

Task of automatic reconstruction of three-dimensional objects by drawing views presented. The algorithm based on a boundary representation of three-dimensional models. The algorithm consists of the following steps: automatic separation of the drawing per the views, determination of three-dimensional coordinates of vertices, definition and marking of wire model primitives, reconstruction of model faces and model elements. The fundamental concept of the algorithm is to find the structural elements of three-dimensional model with usage of pre-specified patterns. The templates are described by means of matrices. Matching algorithm uses spectral graph theory. Reconstruction results are presented.
On Creation of Energy-Saving Hydraulic Impact Devices
Authors: Lazutkin Sergey
Published: April 2015

The article describes the design and operating principle of hydraulic device of impact action with ability of automatic adjustment of new operating mode, depending on the load on work tool.
Development of a Neuronetwork Component for Technical Systems of Mechanical Engineering
Authors: Danilin S.N. , Makarov M.V. , Shchanikov S.A.
Published: April 2015

This article shows the solution to the problem of designing а neuronetwork component of industrial technical system. This solution lets to provide nominal accuracy of information processing, when technical system is working under conditions of destabilizing factors.Base of designing а neuronetwork component is algorithms of elimination of influence of external and internal noise of artificial neural network developed by authors.
Mobile Devices for Plants Models Obtaining with the Possibility of Data Transition (by Ethernet)
Authors: Ilyin Ilya O. , Kudryavtsev A.V. , Onufriev Vadim A.
Published: April 2015

The authors show an identification device, which was developed at Tomsk polytechnic university. First, the main idea of the identification device is given and then they show its structural representation. Furthermore, three versions of complements are considered in the article. These three versions are compared with each other. In the conclusion authors tell about their further plans connected with the identification device.
Development of Parameters Describing Heterogeneous Hardened Structure
Authors: Kirichek A. , Barinov S.V.
Published: April 2015

The technique was developed with the purpose of definition of parameters for surface layer uniformity after mechanical hardening. It was found that one of the most effective methods of surface plastic deformation that provide precise adjustment of uniformity level of surface layer hardening is presented by static-pulse treatment technique. This method helps to develop hardened surface layer 8 mm deep with virtually uniform or heterogeneous structure.
Sulfuric Acid Attack on Various Types of Fine Grained Concrete
Authors: Vyšvařil Martin , Rovnaníková Markéta
Published: April 2015

Sulfate corrosion is one of the major threats for durability of concrete constructions and it becomes a major destructor in sewage collection systems where the concrete sewer pipes are exposed to sulfates from wastewater as well as from biogenic activity of bacteria. During this process the pH of the surface of concrete sewer pipes is reduced and it may lead to steel depassivation and results in the corrosion of this steel reinforcement. This paper is focused on the sulfate attack on fine grained concrete where the effect of 0.5% sulfuric acid, simulating biogenic sulfuric acid corrosion, on changes of pH and content of sulfates in various types of concrete has been investigated. After 3 and 6 months of the corrosive treatment, the content of sulfate ions and pH values in several layers of specimens were determined. It was found that the sulfate ions penetrate into concrete to the maximum depth of 20 mm and the pH of the aqueous leaches of particular layers of the samples was reduced to 11.4 at the most. Thus, the conditions for the depassivation of reinforcement were not met. The GL and GBFS concrete samples showed the least changes of their pH and therefore they had the best resistivity to the six months sulfate attack.
Substitution of Cement-Bonded Particleboards Filling and Binding Agent by Selected Types of Alternative Raw Materials
Authors: Melichar Tomáš , Bydžovský Jiří , Vacula Miroslav
Published: April 2015

The article presents results and findings of the research focused on the modification of composition of cement-bonded particle boards with alternative raw materials. The attention was paid either to binder substitution, either to substitution of filling agent. The modification of matrix composition was realized using the blast furnace slag to 30% of cement weight. Fibrous waste from the glass fiber production was applied as a substitution of wooden chips in the mixture. The influence of both mentioned components was examined separately. The emphasis was laid on strength and elastic parameters and also on durability in view of board resistance to frost.
Influence of Concrete Curing on Modulus of Elasticity
Authors: Křížová Klára , Hela Rudolf
Published: April 2015

The modulus of elasticity is one of the most important properties of the concrete in terms of elastic behaviour of a construction. This parameter is used for the estimation of construction deflections and for assumption of serviceability and calculation of construction deformation. The paper summarises the most important parameters which have essential influence on the development of concrete physical and mechanical properties and mainly on its modulus of elasticity.
Plasters with Decorative Function Containing Alternative Raw Materials
Authors: Melichar Tomáš , Bydžovský Jiří
Published: April 2015

The article presents results of the research focused on modification of special lightweight plasters with decorative function. Several raw material types from secondary resources were used for the formula modifications. The finest fraction of aggregates, i.e. to 0.2mm was replaced with these raw materials. The attention was mainly paid to the thermal technical, diffusion and capillary-sorptive parameters. Except expanded perlite the influence of substitution components did not took any significant effects.
Microstructure of Lightweight and Decorative Renders with Modified Composition
Authors: Bydžovský Jiří , Melichar Tomáš , Žižková Nikol
Published: April 2015

Within the research presented in this article the attention was paid to the study of microstructure of lightweight and decorative renders. The composition of these renders was modified using alternative raw materials in amount of 5 % substituting the finest aggregate fractions. For evaluation of microstructure and its changes the combination of three methods SEM, XRD and DTA was used. Samples for the analysis were prepared from 90-day old specimens. The reason was the evaluation of material structural changes within the mid-term scale because considering the character and amount of used raw materials including the results of physical-mechanical tests no more significant changes were assumed in a short-term period. The performed analyses showed only inessential changes in microstructure of modified materials in comparison with the results of physical-mechanical tests.
The Laboratory Verification of the Absorption of Bitumen Waterproofing Sheets in the Dependence on Selected Parameters
Authors: Plachý Jan , Vysoka Jana , Caha Zdenek , Vejmelka Radek , Petranek Vít
Published: April 2015

This contribution deals with the issue of the weight absorption of bitumen waterproofing sheets. The aim is to determine which parameter the weight absorption depends on, according to the laboratory measurement and the statistical evaluation. This dependence is to be examined based on the results of the weight absorption achieved by the two different testing methodologies [1], [2]. The laboratory measurement was performed on bitumen waterproofing sheets used for waterproofing concrete bridge decks [3].
Temperature Control in High Performance Concrete
Authors: Sedlmajer Martin , Zach Jiří , Hroudová Jitka , Bodnárová Lenka
Published: April 2015

The paper addresses the methodology of temperature observation of cement composites, such as concrete. It is mainly the monitoring of the course of hydration temperature and the possibilities of its regulation. Subsequently, the observation of temperature within samples which are exposed to high temperatures. Attention is paid to a variety of temperatures of a concrete segment which is being acted upon by a high-temperature source, e.g. fire. Temperature distribution at a varied distance from the heat source is observed.
Comparison of Dynamic Young's Modulus of Elasticity Values Measured by Ultrasonic Pulse and Resonance Methods
Authors: Brožovský Jiří , Dufka Ámos
Published: April 2015

Dynamic Young ́s modulus of elasticity can be determined by ultrasonic pulse method and resonance method. Because of the difference in the way of introducing tension into a test specimen, the values of modulus of elasticity differ. Dynamic Young ́s modulus of elasticity measured by ultrasonic pulse method is higher; the difference stated for concrete is 5 to 20%. It was found that the dynamic Young's modulus of elasticity of calcium silicate bricks and prisms measured by ultrasonic pulse method is on average higher by 9.5% than dynamic Young's modulus of elasticity measured by resonance method. If dynamic Young's modulus of elasticity is converted to static modulus of elasticity, this difference has to be taken into account by means of appropriate coefficient.
Beneficial Reuse of Reservoir Sediments in Concrete Production
Authors: Junáková Natália , Junak Jozef
Published: April 2015

This research investigates the potential use of dredged reservoir sediments as a substitute of raw material in concrete production. The first objective is to determine the physical and chemical characteristics of dredged sediments. Based on these sediment characteristics, it appears appropriate to use them as a partial substitute for the natural aggregate in the concrete production. The research results show that concrete mixtures prepared in weight ratio 20 % of coarse-grained sediments as a partial substitute of 0/4 natural aggregate fraction in concrete to 80 % of natural aggregate reached even exceeded the compressive and flexural strengths after 2 and 7 of hardening to those measured in control concrete mixture. After 28 days of hardening, the compressive strength in this mixture slightly decreased (34.44 MPa) in comparison with the control concrete composite (38.30 MPa), while flexural strength measured in the mixture (5.41 MPa) was higher than in control concrete composite (4.93 MPa).
Secondary Raw Materials Obtained from Solar Panels and their Use in Material Engineering
Authors: Hodná Jana , Dufka Ámos , Petranek Vit
Published: April 2015

The paper describes manufacture, use and subsequent recycling method in several types of solar panels. The possibility of using secondary raw materials incurred during recycling is also mentioned – these materials have not found their application so far and their final use is not being dealt. Within the research conducted at BUT, the way of using the secondary raw materials obtained from solar panels in the construction industry is being examined, with a focus on industrial polymer floorings.
Effect of Superplasticizers on the Cement Hydration Process
Authors: Matysík Michal , Vymazal Tomáš , Plšková Iveta
Published: April 2015

The cement hydration is an exothermic reaction. The hydration heat is characterizing quantitatively the clinker hydration degree. Monitoring its time response makes it possible to determine not only the heat released during a certain time interval but also the concrete mix setting onset, the cement hydration degree (when evaluating the cement applicability after a long storage period) etc. The measurement of the hydration heat or the temperature versus time plot for a hydrating mix makes it possible to identify the effect of the different additives and admixtures on the mix hydration kinetics. This paper deals with the effect of adding two different super-plasticizers (lignin-sulphonate-based and naphthalene-sulphonate-based) on the hydration heat development progress. A set of iso-peribolic calorimeters was used to measure the hydration heat development process. The measurement proper consisted in monitoring and recording the temperature versus time plot for the specimen under test. The released heat amount was determined by calculation from the temperature gradient, the ambience specific thermal losses, the material thermal capacity and the test specimen mass.
The Utilization of Waste Aluminosilicate to Prepare Cement Composite with Thermal Insulating and Drying Effect
Authors: Brenek A. , Vaclavik V. , Valíček Jan , Dvorsky T. , Daxner Jaromír , Bendová Miroslava , Šimíček Vojtěch
Published: April 2015

Increasing energy prices, along with escalating demands for thermal insulation properties of enclosure structures, force the owners of buildings to reduce the operating costs of heating. That is why the question of reducing the energy consumption of buildings, also including the category of historical buildings [10], has been gaining ground. The reduction of energy consumption of these buildings is often accompanied by the requirement to eliminate moisture problems of base structures caused by leaking or broken waterproofing of the bottom part of the object. The subsequent increase of the thermal resistance of the building envelope must be performed by means of special insulation materials allowing the drainage of liquid water from the structure. The paper presents the properties and the influence of the developed materials on the course of built-in moisture in the base structure affected by this phenomenon using Delphin simulation software, based on the measured thermal and technical parameters. The developed material is a composition of pozzolan binder, foaming agent and waste resulting from the production of cellular concrete blocks. According to tests carried out in [1], it is possible to produce concretes with sufficient strengths for rehabilitation boards when you substitute natural aggregates with waste aluminosilicate and, according to [2, 3, 4, 5, 6], you will achieve better rehabilitation and thermal insulation properties by using porous filler. The developed material is intended for the so-called soft rehabilitation, and its function is specifically presented on a structure built from sandstone blocks. This type of structures can be found in north Bohemia and the application of rehabilitation work must be very carefully considered, because quick drying of built-in moisture in masonry, for instance by means of cutting the lower part of the structure and by inserting waterproofing, will cause shape changes of the structure accompanied by the formation of cracks.
Production of Alpha Plaster Modification by Pressureless Method
Authors: Fridrichová Marcela , Hájková Iveta , Dvořák Karel
Published: April 2015

The goal of researching works was production of alpha hemihydrate of calcium sulphate by pressureless dehydration method in different solution of chloride salts at same molal concentration. Production was done in innovated dehydration device and main watched parameter was influence of dehydrating solutions based on KCl, NaCl and CaCl2 on properties of produced alpha plaster.
Physic-Mechanical Properties of Cement Composites Consisting of Organic Raw Materials
Authors: Keprdová Šárka
Published: April 2015

The use of rapidly renewable raw materials in the building industry is seen as very promising with regard not only to the environmental issues but also to its economic aspects. A number of producers, not only in this country, have been trying to replace fine construction materials with secondary raw materials or rapidly renewable ones. As an example, technical hemp is a very promising material due to its good mechanical and thermal insulation characteristics. One of the possibilities is its use as filling component for non-constructional filling materials.
Combining binders on the basis of non-hydraulic lime with hemp chaff yields a range of new construction materials. These products offer excellent work characteristics for permanent, environmentally sustainable buildings. These products as a whole form a natural composite construction material that can be used to build insulation walls, floor and roof insulation layers, and to obtain excellent heat and acoustic characteristics of buildings.
FBC – Ash as Principal Constituent of Mixed Hydraulic Binder
Authors: Dvořák Karel , Gazdič Dominik , Kulísek Karel
Published: April 2015

This paper deals with opportunity of FBC – ashes using for hydraulic binder preparation, and as one of the main material for preparation of mixed binders. This way prepared binder should be closed to strong hydraulic limes potentially cements of lower strength classes.
Selected Parameters of Mortars Containing Fine-Grain Modification of Glass and Clay Brick
Authors: Draganovska Martina , Sicakova Alena
Published: April 2015

Today’s world trend in construction and development of building materials is focused to research and development of material systems with properties resulting from dimensions of the components in the micro and nanoscale. Improved mechanical and physical properties, better durability as well as environmental and economic benefits are expected. Such of improved materials represent significant benefit for sustainable construction. In current world, construction and demolitions waste (C&DW) represents useful source of secondary raw materials for production of new building materials. This paper is engaged to assessment of impact the fine particles obtained by grinding of C&DW to technological and physico-mechanical parameters of mortar. Two types of different C&DW which vary in strength and microstructure were used for the experiment: glass and clay bricks. For the assessment of the properties of mortars with application of those ultrafine materials as filler, recipes with 20 and 60% replacement of natural fine aggregate were prepared and tested. Water demand for specified consistency was tested in the fresh state of mortars, while flexural, compressive and adhesive strength was tested after 2, 7, and 28 days of setting and hardening. Given results show positive or negligibly impaired impact of fine grain modification of glass and clay brick on tested parameters.
Modelling of Moisture Behaviour of Brick Fittings Masonry with Filled Hollows with Boundary Conditions of Winter Season
Authors: Brichacek Pavel , Šťastník Stanislav , Rotrekl Ivo , Toman Jan
Published: April 2015

The current trend in the field of materials for vertical building structures is the using of fired brick fittings with filled hollows by thermal insulating material. Fittings achieve a high values of thermal resistance, concurrently, however, the walls built of it are exposed to atmospheric moisture condensation inside the fitting in the winter season. The paper deals with computational simulation and laboratory verification of the moisture behaviour of masonry of brick fittings with filled hollows by fibrous insulating material by duration of boundary conditions of winter season.
Thermal Insulation Plasters Utilising Natural Fibres
Authors: Hroudová Jitka , Zach Jiří , Sedlmajer Martin , Helanová Ester , Reif Martina
Published: April 2015

Natural fibres have been used in plaster reinforcement throughout history. The paper deals with the development of natural fibre reinforced thermal insulation plasters. Given the ongoing research in plaster mixes, there was an effort to develop thermal insulation plasters utilising not only alternative binders but also natural fibres produced in farming. Fibres were both of plant as well as animal origin. The goal of this development of the natural fibre reinforced thermal insulation plasters was to design materials with reduced energy costs, suitable for insulation and rehabilitation of buildings and with good physical, mechanical and thermal insulation properties. Furthermore, thanks to the use of alternative binders and natural fibres, these plasters can be considered environmentally friendly.
Recovery of Magnesium Oxide from Kimberlite Tailing of Panna Diamond Mines
Authors: Kumar Kamlesh , Sharma S.K.
Published: April 2015

Caustic Magnesia is also known as reactive magnesia. In the present study, process has been developed for recovery of caustic magnesia from kimberlite waste of Panna Mine. Panna Diamond Mining Project is the only mine in the country producing diamond. This is an open cast mine producing about 84000 carats diamonds per annum. About 100 tones of kimberlite have to be processed to get 10 carats (2 grams) of diamonds. Thus, about 0.9 million tons of kimberlite waste is being generated annually. Around 6-7 million tons of kimberlite waste is already available at Panna Mines, accumulated over the years waste during mining. Therefore, there is a need to look for development of bulk usage from the kimberlite. Technological option for Eco- friendly & Economically Efficient has to develop. In view of their wide application, and bulk usage, the caustic magnesia was identified to be developed from Kimberlite. Recovery of caustic magnesia from kimberlite tailing of Panna Diamond Mine is a novel chemical process, to prepare caustic magnesia from waste material. The process comprises i) Leaching, ii) filtration of leach liquor, iii) Precipitation of filtrate to get R2O3 and filtrate, iv) Precipitation of magnesium hydroxide, v) Washing and drying of magnesium hydroxide precipitate to remove sodium ions and surface moisture, vi) Calcinations of dried Magnesium hydroxide to get caustic magnesia which can be used in pharmaceutical industries, as animal feed, Mg metal etc.
Exploration of Using Deep Eutectic Solvents to Separate Methyl Palmitate from Simulated Biodiesel Mixtures
Authors: Tang Bao Kun , Lee Yu Jin , Row Kyung Ho
Published: April 2015

Biodiesel purification from the crude biodiesel product has attracted much attention in recent years, and one low cost and simple purification process is urgent to explore. The separation of methyl palmitate from the crude biodiesel products is a key point. In this work, a series of choline chloride based deep eutectic solvents (DESs) is explored as a solvent for separation of methyl palmitate from the simulated biodiesel product. The work showed that the choline chloride-ethylene glycol DES had a excellent effect on the separation of methyl palmitate, and high purity of methyl palmitate were obtained with the choline chloride to ethlene glycol ratio decrease or with the choline chloride-ethylene glycol DES to biodiesel ratio increase.
Preparation of Magnetite-Mg/Al Hydrotalcite through Hydrothermal Process and Subsequent Calcination
Authors: Sulistyaningsih Triastuti , Santosa Sri Juari , Siswanta Dwi , Rusdiarso Bambang
Published: April 2015

Fe3O4/Mg-Al-NO3-hydrotalcite composite compounds have been synthesized by hydrothermal process followed by calcination to learn the differences in physical and chemical properties of each compound. Hydrothermal was performed at a temperature of 120 °C for 5 h and calcinations was at 450 °C for 3 hours. Characterization of the composite compounds was conducted using the Fourier Transform Infrared Spectroscopy (FTIR), the X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and Vibrating Sample Magnetometer (VSM). The characterization results showed that crystallinity, surface area and magnetic properties of hydrothermally treated Mg/Al hydrotalcite-magnetite were higher than those unhydrothermal and calcination products.
Sound Absorption Analysis of Micro Perforated Panel with Ladder Change Type Cross Section
Authors: Ma Zhi Hui , Li Xian Hui , Gai Xiao Ling , Zhao Jun Juan , Zhang Bin
Published: April 2015

A kind of variable cross section micro perforated panel (MPP) with ladder micro porous is introduced in this paper. Based on the double layers MPP theory and neglected the effect of cavity between two layers of MPP, sound absorption model of MPP with ladder micro porous is established. Numerical simulations are carried out to predict the sound absorption of MPP with ladder micro porous. The predicted results show good agreement with measurements. Through analyzing the weight to the sound-absorbing of orifice size, this study also points out that the smaller orifices play the major role in the sound absorption.
Thermogravimetric Analysis and Chemical Kinetic for Regeneration of Sodium Carbonate Solid Sorbent
Authors: Chaiwang Pilaiwan , Chalermsinsuwan Benjapon , Piumsomboon Pornpote
Published: April 2015

In this study, non-isothermal kinetic methods for the decomposition of the adsorbed CO2 on pure sodium hydrogen carbonate (NaHCO3) were investigated by a thermogravimetric analysis (TG) and differential thermogravimetry (DTG). Four different heating rates were measured to calculate the order of reaction (n), the pre-exponential factor (A) and activation energy (Ea) using three different models: Kissinger-Akahira-Sunose Method (KAS), Flynn-Wall-Ozawa (FWO) and analytical method. The results showed that KAS and FWO methods gave similar values due to the approximation of employed equation whereas the analytical method gave different values. The obtained parameters from those three methods then were used to calculate the chemical reaction conversion versus temperature and their R2. The results showed that analytical method provided the most accurate results comparing with KAS and FWO methods.
Thermal Stress Cleaving of Si-Wafer: Investigation of Fracture Initiation during Laser Beam Irradiation
Authors: Saman Alias Mohd , Furumoto Tatsuaki , Hosokawa Akira , Ueda Takashi
Published: April 2015

This paper investigates the fracture initiation at the vicinity of a micro-groove caused by thermal stress through computational and experimental studies. Fracture initiation time has been determined by analyzing the stress intensity factor. Stress distribution was examined by using a finite element method, and the fracture toughness of the material was determined by using a Vickers indentation technique. The fracture initiation process was verified experimentally by monitoring the acoustic emission signals, while the temperature of the laser spot was also measured using two-color pyrometer. The result shows that stress intensity factor was increased with the increase in micro-groove sizes. Consequently, fracture initiation was attained faster. The simulation results show a good agreement with the experimental results in examining the fracture initiation and recognizing the ideal micro-groove parameters for laser cleaving process.
Hybrid Nanocomposite Material for EMI Shielding in Spacecrafts
Authors: Tariq Fawad , Shifa Madni , Tariq Mateen , Kazim Hasan S. , Baloch Rasheed Ahmed
Published: April 2015

In this study lightweight carbon fiber and multiwalled carbon nanotubes filled hybrid nanocomposite was fabricated for electromagnetic interference (EMI) shielding in spacecraft. Electrical conductivity was conducted to assess the affect of MWCNT addition on composite. EMI shielding effectiveness (SE) was tested in the frequency range of 1-18 GHz. Comparison of SE was also made with AA6061-T6 sheet. Dispersion of nanotubes in the matrix was examined through microscopy. Results indicated that the conductivity was increased with increasing MWCNTs up to 0.25 wt%. Higher loading level of MWCNTs has resulted in decrease in conductivity due to agglomeration in cured samples. Hybrid nanocomposite exhibited improved SE than AA6061-T6 in 1-8 GHz frequency range. Best SE and electrical conductivity was witnessed in 0.25 wt% MWCNT sample. EMI SE in range of-20 dB to-40 dB can be easily achieved in our developed material.
Influence of Graphene Nanoplatelet Filling in Thermoplastic Natural Rubber Antistatic Nanocomposite Using Combination of Solution and Melt Mixing Method
Authors: Siriyong Tutchawan , Keawwattana Wirunya , Kim Jin Kuk
Published: April 2015

A simple combination of solution mixing and melt mixing method for the preparation of fully exfoliated and dispersed graphene nanoplatelet (xGnP) in thermoplastic natural rubber (TPNR) as NBR/PVC (NVC) blend (70:30) has been successfully demonstrated. Two different types of H5−xGnP (~53 layers) and C750−xGnP (~16 layers) were used in this study. The amount of xGnP filled in the nanocomposite has been varied from 0-3 phr. The electrical and mechanical properties of filled TPNR nanocomposites were increased with the increase in both of xGnP types loading. The results suggest that the process provides us a much better dispersion and exfoliation of xGnP into the matrix than direct mixing method. With comparing xGnP types, the number of layer stacked xGnP has significant effect on the tensile strength and electrical conductivity of nanocomposites, the lower the number of layer stacked xGnP, the higher mechanical and electrical properties. The tensile strength of pre−dispersed H5− and C750−xGnP−NR/NVC nanocomposites at 3 phr loading were increased by ~16 % and ~34% respectively compared to conventional direct mixing. While dramatic enhancement of electrical conductivity for the pre−dispersed H5− and C750−xGnP/TPNR nanocomposites has been changed from insulating range to antistatic range.
Tribological Properties of MWCNTs Strengthened Aluminum Composite Fabricated by Induction Melting
Authors: Mansoor Muhammad , Shahid Muhammad
Published: April 2015

Aluminum-Multiwalled carbon nanotubes (Al-CNTs) composite was fabricated using air induction melting technique. The nanotubes were dispersed in molten aluminum using innate string action of induction heating at 760 °C. A heavy fluxing condition was used to avoid oxidation of the nanotubes and molten aluminum. The nanotubes were satisfactorily dispersed in the matrix as observed during metallographic examination using scanning electron microscope.
 
  The tribological properties (i.e. coefficient of friction and wear rate) of the Al-CNTs composite were investigated using ball-on-disk machine under dry wear condition at 2 cm/sec speed and 3N load. It was observed that both of the tribological parameters exhibited decreasing trends with increasing contents of the nanotubes, which was due to the self lubricating and structural features of the nanotubes. Improved tribology of the composite was the attribute of appreciable dispersion of the nanotubes in the matrix besides their exceptional mechanical properties and reinforcement.
Research on Heat Resisting Epoxy Resin System for Liquid Composite Molding
Authors: Wu Qing Qing , Xiao Jia Yu , Liu Jun , Xing Su Li , Yang Jing Shui
Published: April 2015

The properties of heat resistance and manufacturability of epoxy resin system are contradictory to each other. In order to maintain the balance of both properties, this article studied the heat resistance (testing the glass-transition temperature using differential scanning calorimetry) and the manufacturability (characterizing the variation trend of viscosity at molding temperature using AR2000EX rotational rheometer) of two kinds of epoxy resin systems by means of designing orthogonal table. Studies show that when the mass ratio of hydantoin epoxy resin, MF-4101 epoxy resin, anhydride and accelerant is 100:20:150:1.5, the glass transition temperature of the epoxy resin system can reach over 180°C. What’s more, the initial viscosity of the epoxy resin at 40°C is about 230mPa•s, and the viscosity can maintain no more than 800mPa•s in approximately 3 hours, which meets the requirements of liquid composite molding.
Gas Control Technology under Unstable Disturbance Stress
Authors: Cheng Wei Min , Sun Lu Lu , Wang Gang , Qu Hong Yuan
Published: April 2015

Under the action of unstable disturbance stress, the stress concentration and roadway deformation are serious when tunneling along the goaf with small pillar while the adjacent working face is mining. This leads to the abnormal gas discharge and the increase of gas emission, and the effectiveness of gas drainage is reduced. In order to eliminate the threat of gas, the dynamic gas control technology of tunneling along the goaf with small pillar under unstable disturbance stress has been researched. The main sources of loads are confirmed by the analysis of dynamic and static loads. Combined with the force analysis of roadway and pillar, the stress superposition level is affected by the relative location of heading face and working face, and the regional characteristics. The measured surrounding rock deformation of A4007 return roadway heading face fits the theoretical analysis and pressure step of working face. The dynamic gas control technology is researched from the aspects of air volume, high-level gas drainage and goaf drainage, and applied in A4007 working face. The gas has been well controlled with the gas concentration of top corner of 0.62% and gas concentration of return current of 0.35%. As a result of the flow control, the gas drainage has not casused spontaneous combustion.
An Assessment of Extended Surfaces-Two Dimensional Effects
Authors: Okiy Karinate Valentine
Published: April 2015

This article looks at the effects of considering two-dimensional temperature distributions in analyzing different fin configurations (radial rectangular fins, planar rectangular fins) in contrast to the one-dimensional assumption commonly used in most design methodologies. The investigation of the temperature distributions along the length of the extended surfaces was performed both analytically and by using Computational Fluid Dynamics (CFD) software. The results obtained were then compared and the observed deviations reported. From these investigations, it was discovered that the one-dimensional approach does not always give good results for the heat fluxes and temperature distributions for plain and radial rectangular fins. This calls into question the validity of the one-dimensional assumption utilized in the design methodologies for heat exchange equipment incorporating plain and radial rectangular fins. Keywords: Fins, heat flux, heat transfer coefficient, Temperature distribution, One-dimensional analysis.
Age-stage, two-sex life history of the golden twin spot moth,Chrysodeixis chalcites(Lepidoptera: Noctuidae), on six commercial tomato cultivars under laboratory conditions
Authors: Nouri-Ganbalani Gadir , Mardani-Talaee Mozhgan , Haji-Ramezani Mohamad Reza
Published: April 2015

The tomato looper,Chrysodeixis chalcites(Esper) (Lepidoptera: Noctuidae), is a major pest that feeds on some fodder crops, vegetables, and ornamental plants in diverse plant families. We studied the effect of different cultivars of tomato including: Cal.JN3, Hed Rio Grande, Rio Grande UG, SUN 6108 f1, Super crystal, and Super strain B on the life history ofC. chalcitesunder laboratory conditions (25±1 °C, 65±5% relative humidity, and 16:8 (light:dark hours). Data were analysed using the age-stage, two-sex life table method. Tomato cultivars had significant effects on developmental time of larvae, pupae, and total preadult stages ofC. chalcites. The longest (17.39 days) and the shortest (13.93 days) larval period were observed on Hed Rio Grande and SUN 6108 f1, respectively. The longest pupal period was observed on Cal.JN3 (12.16 days) and Hed Rio Grande (12.11 days) compared with other cultivars. The lowest amount of larval growth index and rate of ovipositon days was observed on Cal.JN3. The results of this study revealed that Cal.JN3 and Hed Rio Grande were the less suitable cultivars toC. chalcitescompared with other cultivars studied and can be used in integrated pest management programme of this pest.
Riser Solutions for Turret-Moored FPSOs With or Without Disconnectable Turret
Authors: Seguin Blaise , Karunakaran Daniel , Legras Jean-Luc
Published: April 2015

Turret-Moored FPSOs are more and more used for deepwater developments worldwide, with consideration of disconnectable turrets for harsh environment applications. This trend makes the interactions between FPSO and riser system, and the optimized selection of the riser system, of greater importance.

The paper provides a review of the various riser systems that can be considered for turret-moored FPSOs: proven systems, both coupled (flexibles and rigid risers) and uncoupled systems (hybrid single and multiple riser systems), and new riser concepts. These systems are described in terms of design and functionalities; fabrication and installation methods are presented.

Pros and Cons for these riser systems are discussed, with consideration of the particular challenges brought by turret-moored FPSOs (e.g. large floater motions, riser hang-off geometry constraints at turret, hang-off loads, riser interferences, riser pre-installation, turret disconnection constraints). Elements for selection of the most appropriate riser system are proposed, considering a range of project specificities.