The aim of this work is to evaluate changes of nitinol structure in the condition of austenite and martensite during grinding of surfaces. Different abrasive wheels and constant grinding mode were used in the experiment. The composition of nitinol was studied by x-ray phase analysis. It was found that the grinding of nitinol, when it is in austenite state better retains phase fraction than in martensite state. Grinding leads to secondary intermetallic compounds formation, as well as basic phases decrease as compared with the parent state. Abrasive wheel characteristics have a noticeable but not unambiguous effect on the stability of the phases. NiTi phases’ content boundaries, as well as their absolute change after grinding have been determined.

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This study investigated the performance of geopolymer bricks that were produced using fly ash, chippings and sodium hydroxide (NaOH) solution. Brick mixtures were designed with solution-to-binder ratio of 0.35. The NaOH solutions of 5, 8, 10 and 12 M were used as alkaline activators. The effect of NaOH concentration on properties of geopolymer bricks, including compressive strength, ultrasonic pulse velocity, thermal conductivity, and electrical resistance was investigated. In addition, the scanning electron microscope (SEM) was also used to observe the microstructure of geopolymer bricks. Test results indicated that the compressive strength, ultrasonic pulse velocity, thermal conductivity, and electrical resistance of geopolymer bricks increased with increasing NaOH concentration. Furthermore, SEM micrographs showed a higher hydrate rate of fly ash in brick samples with higher NaOH concentration. All brick samples investigated in this study exhibited a good quality with compressive strength of above 10 MPa, ultrasonic pulse velocity of above 2500 m/s, and electrical resistance of above 2 k?-cm.

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This paper presents the design and implementation of a virtual and remote laboratory created for controlling a speed plant located in the control laboratory at Surcolombiana University. The aim purpose is that the student has the first contact with the plant (virtually) before working with the physical one, understands its operation, restrictions and prevents any damage to the same equipment. Students can handle the actual plant remotely by another application created for this purpose, enabling it to take data that later will serve for the identification, processing and implementation controllers designed to meet the desired specifications. Also, it has an IP camera to visualize and understand the effects of its running. The project is based on the Easy Java Simulations software (EJS), responsible for all the interactive and visual interface part, linked to the Matlab software. Performance validation of the generic controller was carried using Matlab tools, achieving great results, confirming the reliability of the applications created.

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Error Correcting Codes such as Reed Solomon (RS) and Bose, Chaudhuri, and Hocquenghem (BCH) are widely used in communication and storage systems in order to correct and control errors introduced by transmission channel. In this paper, a simplified algorithm for RS and BCH decoding is proposed with a view to reduce the number of components compared to the basic chien search block. First, we developed the design of the proposed algorithm second, we generated and simulated the hardware description language source code using Quartus software tools and finally we implemented the new algorithm of chien search block on FPGA card.

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This paper presents the analysis of pressure tests in unconventional reservoirs from the trilinear model of anomalous diffusion based on fractal geometry and anomalous diffusion in order to simulate the heterogeneity of flow in the reservoir in order to be able to obtain a flow prediction approximate to the real. Based on this model, we generate curves in which by applying the TDS methodology, new equations to determine reservoir parameters such as internal reservoir permeability, hydraulic fracture permeability, fracture conductivity, and reservoir dimensions are created. Likewise, through the input of the parameter alpha (a) four cases are defined, which show the variation of the flow depending on the connection between its elements. Finally based on data obtained from the literature, pressure tests were simulated in order to verify the right operation of the equations and that are within the error tolerance range.

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The paper presents the results of laboratory studies on the manufacture of AlTi grain refiner. The developed technology includes self-propagating high-temperature synthesis of Al3Ti from a titanium sponge and molten aluminum; mechanical grinding of Al3Ti; adding of ground Al3Ti particles into the aluminum melt. The modifying ability of the experimental AlTi modifier is not inferior in effectiveness of the AlTiB at the same titanium content in the modifiable metal.

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The dental fillings in the cavity of a diseased tooth are improving by leaps and bound. Nano composite with improved mechanical properties are been invented. Recent composites display improved properties in specific area. There is a need to have a holistic approach to have a improved dental composite with balanced mechanical properties. An attempt has been made to fabricate a dental composite using Zirconia as a filler and Bis-Gma and TEGMA as matrix. Optimization of Tensile strength in the experimental dental composite has been a major challenge, while balancing other mechanical properties. Taguchi’s optimization technique keeps the experimentation within limit giving valid results in the domain of tensile strength optimization.

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The influence of the acidity of the solution on the properties of salts of polyhexamethylene guanidine was studied by the UV-spectroscopic method in this work. The studied guanidine compounds can not participate in chemical reactions in an equivalent ratio due to the complex structure of the molecule under certain conditions. Therefore, the influence of the solution acidity and type of destruction on the properties of hexamethylenediamine salts, which are the products of chemical destruction of polyhexamethylene guanidine salts, was studied. The possibility of a reaction between the organic cations of the studied guanidine compounds and the anions of the 12-molybdophosphate heteropoly acid of the Keggin structure was investigated and the nature of the bond in the obtained compounds was determined. The composition of the complexes and the ratio of components in the reactions of polyhexamethylene guanidine, hexamethylene diamine and 12-molybdophosphate heteropoly acid were determined by the saturation method. The results of these studies can be used to develop methods for the determination of salts of polyhexamethylene guanidine and hexamethylenediamine in various industrial facilities using the ionometric method using potentiometric sensors sensitive to polyhexamethylene guanidine and hexamethylene diamine.

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The paper considers the specifics of tunneling in the complicated geological conditions of the Metrostroy Saint Petersburg mines using the Herrenknecht S-782 shield machine. The techniques for defining the cutting force in the tool face have been analyzed. The dependence of the total torque of the shield machine cutter head shaft has been plotted. An option of the cutter lacing pattern on the rotary cutter head of the shield machine has been proposed.

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Multi-carrier code-division multiple access system support multiple users at the same time over same frequency band. It is a multiple access scheme used in OFDM-based telecommunication systems. Though it is a promising wireless communication technology with high spectral efficiency and system performance, it is prone to multiple access interference (MAI). So, this paper mainly aims to design a MC–CDMA receiver to mitigate MAI. The classical receivers like maximal ratio combining (MRC), equal gain combining (EGC), and minimum mean square error (MMSE) fails to cancel MAI when the MC– CDMA is subjected to non-linearistic degradations. In this case, the neural network (NN) receivers could be a better alternative. The efficiency and effectiveness of the proposed ELM (Extreme Learning Machine) Algorithm based receiver is studied thoroughly and explained in detailed for the MC–CDMA with non-linearistic degradations.

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Modern MBTs (Main Battle Tanks) last more than 30 years. During this period, they will be periodically upgraded in any aspect except the basic structure. Even the main armor is becoming an upgraded accessory that depends on the nature of the threat. The main armament may be also changed or upgraded. The huge electronic equipment is the most upgraded part. The crew compartment may be upgraded in internal armor (for example for spalling), interfaces (optics, displays, commands), safety and protection devices (fire detection and suppression, ejection seats..). This continuous upgrade process should be included in the design of new vehicle, than can be modular for these mid-life upgrades. The vehicle is designed by adding items to the crew compartment and to the mobilization system. As an example, this first part introduces a few options to retrofit the ARIETE MBT. The retrofit cannot be reduced to engine and armor upgrade. A reasoned step approach is outlined in this paper. The first minimal step is based on an active armor and an HMD (Helmet Mounted Display) visual system. The weight increase is compensated by reducing road wheels weight. A second step increases firepower by installing on the main turret an automated turret with an automatic small cannon and a machinegun. The weight increase is compensated by limiting the internal ammunition storage of the main cannon to the anti-tank ones. A third step converts the turret internal ammunition storage into an automatic reloading system. In this way, the crew is reduced from 4 to 3. A fourth step increases crew safety by relocating the driver in the turret and by installing ejection seats. Solutions to reduce ground pressure and to increase the effective “power” available by replacing the final-drives and adding two electric motors on the front sprockets are also briefly examined. It is also highly advisable to add an APU (Auxiliary Power Unit) to reduce IR (infrared) signature, improve main engine life and reduce maintenance.

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Abstract:

Great opportunities for improving the open-pit mining operations technology and increasing their efficiency are laid in the temporary conservation of overburden rocks and leaving a temporary basset edge within the quarry. This is due to the desire to reduce the volume of mining and stripping operations in the initial periods of quarries exploitation. To reduce costs, it is advisable to plan incremental surface mining with the establishment of pushbacks. Phased formation dynamics of the working zone of opencasts and development technologies should ensure the implementation of the projected volumes of mining and the possibility of their simultaneous intensive development within the boundaries of different stages. There are objective trends of deterioration of mining-and-engineering and mining-and-geological conditions of open-cut mining of steeply dipping deposits, in the context of dynamic markets, changes in prices, and demand for mineral raw materials. The creation of stages and pillars may be caused by the decision to reconstruct the quarry. In this case, an existing final pit boundary will serve a pushback. The process of creating a temporary basset edge was carried out when the movement of the loading faces reached the mine abandoning stage. Development of deposits in stages allows in some cases ensuring the economic feasibility of mining, and the necessary rate of return. The authors proved the necessity of forming a temporal basset edge of ore in the context of changing economic situations.

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