Oven curing gives effect to the strength of geopolymer mortar. The geopolymer mortar treated by curing oven with measured duration and temperature. Temperature and term used in the oven curing on the geopolymer mortar. They affect the strength of geopolymer mortar. This study aimed to determine the connection of duration and temperature used in the curing oven to the compressive strength of C-type fly ash based Geopolymer mortar. The constituent material of geopolymer mortar is activators, fly ash, and sand - the activator using NaOH and Na2SiO3. A comparison of fly ash and sand is 1: 2.75. Comparison NaOH: Na2SiO3 is 1: 2 and 10 M NaOH. Oven temperature variations used 45°C, 65°C, 85°C, 105°C, and 125°C, and differences in the duration of use 20 hours, 10 hours, 8 hours, 6 hours, and 4 hours. The results showed that the connection of temperature and term used in the oven curing of the compressive strength of geopolymer mortar is significant. The relationship between duration and compressive strength has a non-linear polynomial equation negative. The period and temperature optimal for curing C-type fly ash based Geopolymer mortar is the temperature of 105°C and the duration of 8 hours.

Full Text

This study investigated the greenhouse gas emission of compost products from community composting plants. Aged wastes from agricultural and agro-industrial sources used as raw materials for composting with intermittent forced aeration static pile composting application. Investigation of two types of compost products, including powder and granular shapes, revealed that the powder composting process emitted CO2 and CH4 gases as 730.23 kg and 4.81 kg, respectively, during the composting process, while the granular composting process emitted 784.38 kg CO2 and 3.39 kg CH4. An additional liquid mixture for granular formation contributed to higher emissions of CO2 and CH4 compared to the powder composting process. These data are useful for conducting life cycle assessments to evaluate and improve the environmental performance of community composting systems.

Full Text

The development of high performance photovoltaic technology for fulfill renewable energy demand is grown in enormous progress which reflected by many kind of solar cell. Started by silicon and thin film based, photovoltaic power conversion has been boosted to the highest level with high cost requirements. Dye sensitized solar cell (DSSC) arrived to answer a low cost solar cell, but still estricted by low power conversion factor. We fabricate DSSC based on ZnO nanomaterial by layering the nanostructure with boron, a promising metal dopant. In this paper we report a role of time immersion to the performance of the cell. The nanostructure was successfully grown on fluorine tin-oxide (FTO) by seed-mediated hydrothermal method at 90oC for 8 hours. The nanomaterial was immersed by boron solution for 10, 20, 30, and 60 minutes. Samples were characterized by UV-Vis spectroscopy, X-ray Diffraction (XRD), field emission scanning microscope (FESEM), and energy dispersive X-ray (EDX). While the performance of DSSC cells is measured by analyzing the characteristic curve of I-V. The cells are fabricated by arranging cells to form sandwich structures, which consist of FTO, ZnO nanomaterials, dye, electrolyte, and a counter electrode. I-V characterization of cells carried out under standard irradiation of 100 mW.cm-2 halogen lamps. The highest power conversion factor of 0.25% is obtained at 30 minutes boron immersion time.

Full Text

The aim of this project is to optimize the round shape portable vacuum clamping based on machining parameters. The selected machining parameter is spindle speed, depth of cut and feed rate. The vacuum clamping was tested to evaluate and analyse the result of surface roughness and time setting. The result shows that the portable round shape vacuum clamping is the best clamping system compare with conventional vise in term of setup time. The time is taken for setting the workpiece on the clamping device for vacuum clamping is 13.6 seconds which is faster than conventional vise 54.7 seconds. For surface roughness, the smooth surface is 1.627 µm at 910 RPM of spindle speed. 910 RPM spindle speed is most suitable for machining 0.5mm depth of cut on portable round shape vacuum clamping.

Full Text

Fly ash is a side waste from the cement industry that can damage the environment. Fly ash has the potential as an essential material in making geopolymers. The study discusses how the relationship of the use of activator composition with the compressive strength of geopolymer mortar using fly ash. The sample uses activator sie NaOH and Na2SiO3. The sample uses several variations of NaOH composition and alkali modulus. NaOH variations consist of 13 M, 14 M, 15 M, and 16 M. Variations in alkali modulus include 1.5, 1.75, 2.00, 2.25, and 2.50. Treatment of samples according to room temperature and compressive strength testing was carried out at 7, 14, 28, and 56 days. Research has shown that the correlation between NaOH and alkali modulus on mortar strength is very significant. The highest compressive strength occurs at 14 M of all variations. The relationship of activator composition and compressive strength form 2nd polynomial equation order and NaOH optimum composition occurs between 14 and 15 M.

Full Text

The objective of this study is to investigate the effects of welding parameters in the welding process on the mechanical properties and micro structure to compare the design of experiment (DOE) for the high-frequency resistance welding process (HFRW) of ASTM SA-192high-carbon steel. The different butt weld T joints of finned-tubes were prepared by varying the welding parameters, including current (A), voltage (kV) and frequency (rpm) which were also related to the heat input and mechanical properties. DOE analysis of the welding parameters was performed at 9A, 13kV, 250 rpm and heat input of 474 J/mm. The results showed that the ultimate tensile strength was 749 MPa which meets the standard requirements of the Association of Finned Tube Manufacturers and is at a good level in the production viewpoint. However, the examination of the micro-and macrostructure of the weld line using an inverted microscope showed some melting on the specimens and it was found that some specimens had high weld width and weld depth. In addition, the tensile strength was also higher. However, too high tensile strength was changed the material structure, the cause of HAZ. Through the validation of the welding process which was compared to the fatigue strength, the following results were indicated: (1) the ultimate tensile strength at the highest tensile stress was not the ultimate fatigue strength and the heat input affected the weld width and weld depth of the weld line. (2) In the welding process, the weld width and weld depth must be also considered since they can affect the specimen failure during the experiment. Therefore, extreme care must be taken when using a high-frequency resistance welding process.

Full Text

The line capacity of fixed block signaling is reciprocal of the minimum headway and is defined as the maximum number of the train that can pass through a stretch of track per unit time for safety reason. By using the Communication Based Train Control (CBTC) technology all trains continuously communicating their exact position. Therefore, the safety distance was no longer a static entity but an adjustable distance (moving block) based on a real-time calculation of the train speed. There will no longer wasted space so the line capacity will increase. The prototype form implemented in four sub-systems, the first one is signal generating system consisting of an oscillator circuit and amplifiers to generate AC signals and flow it to the loop cable produce electromagnetic waves, the signal processing sub-system which serves to read the oscillator signal on the loop cable by using the coil, data processing and communication sub-system processing signal output and send data to the server and the radio frequency identification as the wayside equipment for calibrating the position. The output of this implementation is sequence number of blocks that have been passed by the train and the information of the RFID tags used to calibrate the position of the train. By using that information, we can determine the position of the trains and kept the trains close to each other while maintaining a safety distance.

Full Text

This paper presents a new study to reduce fluctuations in the calculation of reactivity. The inverse equation of point kinetics is solved with an approximation in the neutron density history using the Euler-Maclaurin method. An exponential filter is implemented to reduce the fluctuations in the neutron population density. These fluctuations are simulated using a Gaussian noise with zero mean and unity variance around the average power.

Full Text

Supercomputers are widely used across variety of industries. Civil Engineering methods of numerical modelling are conservative and new technologies are used only occasionally. As numerical models become more complex with more detailed material models and a more extensive construction model, the limits of standard workstations are often reached. When a large task with many unknowns and nonlinearities needs to be solved, the demands on hardware requirements are high. In such cases supercomputers are convenient because they allow to solve larger tasks then a standard workstation Low computational time is another advantage of a supercomputer. Finally, the supercomputer doesn't need a huge investment from the user, because only computing time is rented. Appropriate resource allocation is essential to maximize the computational potential of a supercomputer. The task in this article is aimed on a soil-foundation interaction. The Ansys HPC commercial software was used for the calculations on the Anselm cluster in the National Supercomputing Center IT4 Innovations in VSB-Technical University of Ostrava. The optimal method of resources allocation was observed and discussed with regard to task size and a calculation time. The article consists of two examples. First example was computed on 16 nodes with the 16 Ansys HPC licenses with various methods of recourses allocation. The second example evaluated using all available HPC licenses in the National Supercomputing Center IT4Innovations. The maximal possible task size was evaluated in all used methods.

Full Text

The geometrical imperfections present on the shell structures can be classified into distributed geometrical imperfections (present on the intact plate) and local geometrical imperfections. One of the local geometrical imperfections is dent. In the present work, a new approach was adopted to map the measured geometrical imperfections on FE mesh of perfect plate model using 3D interpolatable surface model option of Matlab, to model imperfect plate models. Here, eight test plate specimens of size 500mm x500mmx5 mm (2 intact plates, 2 transversely dented plates, 2 longitudinally dented plates and 2 dented plates with approximately 45° dent orientation) were fabricated in order to study the combined effect of distributed geometrical imperfections and centrally located dent on their ultimate strengths. Before testing the specimens for the ultimate strength experimentally, geometrical imperfections present on the plate specimens were recorded using 3D scanner and this actual geometrical imperfections were mapped on the FE meshes using 3D interpolatable geometrical imperfection surface model. These imperfect FE plate models are analyzed for their ultimate strengths under axial compression with simply supported boundary conditions using Non-linear FE analysis of ANSYS. The results obtained from numerical analysis and experiments are compared and are found to be match each other reasonably.

Full Text

In this article the authors consider the motion patterns of how a material particle is moved with a spiral surface in a random direction when the spiral rotates. To obtain the differential equation of motion, all forces are considered, including the inertia forces applied to the particle on the helical line of the spiral. The angle ? between the normal reaction of the surface of the spiral turn and the Oy axis has been considered, which characterizes the geometric characteristics of the helix, a cylindrical casing and particle size in the spiral and helical device. To obtain data on the nature of particle motion, numerical integration of the obtained equations for spiral devices with various parameters was performed.

Full Text

Abstract:

This paper is devoted to the consideration of mathematical modeling of heating processes occurring in the drying section of paper-making machine. The main attention is paid to the thermal processes issue occurring at the first stage of paper web drying, the heating. An algorithm for calculating the paper temperature change during its passage through drying cylinders and areas of free movement has been developed. The basic equations for calculating temperature of contact and central layers of the paper web are derived. The formulas for calculation auxiliary parameters of the process are given in the paper. The generalization of the obtained data in the resulting formulas form of the convective and contact periods of the paper web heating is executed. Using the statistical criteria of Student and Fisher, the check for the adequacy of the proposed mathematical model suits the actual working process has been made. The developed mathematical model will be used for simulation modeling of automatic control systems of this process.

Full Text

Hydraulic pumps have played a decisive role in the development of humanity. Clean and accessible water is an essential ingredient for a healthy life all over the world. Renewable energies are called to move the world, you can no longer rely on oil for much longer. Autonomous spiral pumps have been built that work with the kinetic energy of the water flow. The aim of this research was to develop a procedure for the optimal design of the spiral pump. The numerical simulation of the model is performed in a CAE environment, using octave software. The design of the pump elements and the simulation of their mechanical properties are performed with CAD tools from software. The design and validation developed ensure an optimal design, which facilitates the task of decision making for manufacturing.

Full Text

At the present stage of automatic control systems development, the question of maintaining temperature specifications comes up. The authors developed a synthesis technique for nonlinear controllers to stabilize the temperature field of control object. The resulting controller allows to create an adaptive controlled system to maintain the temperature field - for this it is necessary to analyze the control system in order to find optimal number of heating elements to stabilize the temperature field. This article considers the issue of stable occurrence of thermal processes while stabilizing the temperature field. Thermal processes in furnaces for various purposes are considered, in particular in drying and roasting chambers. The control system and stabilization of the temperature field are reviewed.

Full Text

Scheduling is a setting process on a system for better service. One of the system that uses scheduling is the Long Term Evolution (LTE) network. Scheduling on Long Term Evolution is used for allocating radio resource to serve users at a certain frequency and time. One of the methods that can be used is by using channel scheduling algorithm for uplink LTE direction. Exponential rule algorithm has the advantage of being able to support a fair system fairness index, but unable to maximize throughput user. On the other side, maximum throughput algorithm is able to maximize user throughput with the best channel condition, but has disadvantage on the fairness index side. This study will analyze the comparison between exponential rule and maximum throughput for LTE network uplink channel scheduling based on throughput user and system fairness index. This study uses 4 scenarios with variations in the distance of 1-4 km and variations in the number of users 4, 8, 12, and 16 in 2 track conditions, namely LOS (Line of Sight) and NLOS (Non-Line of Sight).

Full Text

This research paper provides some results of the research aimed at finding the optimal content of vitamin A in the diets with bagasse pellets for experimental calves that causes certain pharmacological effect during final fattening. Three groups of calves at the age of 12 - 13 months with the body weight of 290 - 310 kg were formed for the scientific and economic experiment by the principle of pairs-analogs, 15 animals in each group. The calves in the first group received 20 - 22 thousand Weight Units (WU) of vitamin A per 100 kg of live weight, which was equivalent to the standards of the RAAS (according to Kalashnikov-2003) in terms of carotene (1 mg of carotene is equal to 400 WU of vitamin A), in the second group - more by 25 % (25 - 27 thousand WU/100 kg of live weight), and in the third group - more by 50 % (30 - 32 thousand WU/100 kg of live weight). The level of vitamin A was regulated by Microvit A with the pharmacological activity of 500 thousand WU per 1 g. It has been found that the optimal pharmacological level of vitamin A in the diet is about 25 - 27 thousand WU per 100 kg of live weight. This improves the average daily gain by 11.5 %, increases the weight of the carcass by 6.4 %, including boneless meat - by 7.4 %, and improves beef quality.

Full Text

Mechanically Stabilized Earth walls (MSEW) have been showing improved performance and acceptance level among engineers and contractors recently particularly when used to widen roads to accommodate large traffic or as ramps for bridges. MSEW have a number of advantages over traditional reinforcement concrete walls among which; it can reach more heights at a reasonable cost. The need for higher retaining walls requires the tendency for new techniques. One of such techniques is the use of large geogrid spacing. In such a case there is a number of solutions, among which is the use of wire mesh to prevent local failure at the face of the wall due to the large spacing. This paper investigates the maximum tensile force in hybrid MSEW over the height of the wall as well as along the geogrid length for different soil friction angles. Finite difference analysis is used to model a 16 m height instrumented MSEW. Mohr-Coulomb is used to model the soil as well as the gabions face panels, interface elements were used between the geogrids and the soil. Verification was done using instrumented readings from the field. Five friction angles, Ø=22° Ø=26° Ø=32° Ø=36° Ø=42.9° were used for the parametric stud, and a traffic load of 20 KN was included in the investigation. Results of the study show that the maximum tensile force in the geogrids increases as the strength of the soil is reduced by decreasing the friction angle. The maximum tensile force in the geogrid varies with the geogrid vertical position within the wall. The maximum tensile force in the geogrid was found to be at around one-third of the wall height. The position of the maximum tensile force in a geogrid tends to move away from the face of the wall as the angle of friction decreases.

Full Text

In tropical regions, rain is the dominant source of attenuation at higher frequency bands in Satellite Links. Rain degrades the system performance with increased Path Loss. Knowledge of rain fade performance is essential in order to optimize system capacity, quality and reliability. The rain intensity data is derived from140 years measured annual rainfall data worldwide. The converted rain intensity data is used to estimate rain fades at C, X and Ku-bands using ITU-R recommendations. Noise generated, carrier-to-noise ratios during rains are estimated and compared for all the mentioned three bands. This paper presents the effects of satellite to earth link on the performance of receiving system due to rain fades operating in tropical country like India. Currently in India C and Ku-band frequencies are being used for commercial satellite communications.

Full Text

The main factors of car accidents were statistically investigated in Jordan. The car accidents were classified into three major categories, collisions, rollover and run over accidents. As the human errors were found to be the major reason for all kinds of accidents, they were classified into thirteen types of errors. The most serious errors of drivers causing accidents were failing to take correct measurements during driving, tailgating and incorrect lane taking. As the percentage of female drivers is less than 25%, they were found to make more collisions than male drivers, but male drivers make more run over and rollover accidents. Young male drivers were found to make more accidents than old ones. But young female drivers made less accidents than middle age and old female drivers. Statistical significance analysis showed that driver errors are the major factors of accidents in general, and collisions and turn over accidents in specific.

Full Text

Wastewater produced from the water management process must be in accordance with environmental quality standards in order to reduce the potential risk for environmental damage and human health. One of the pollutant compounds in wastewater that is the problem in this article is Chemical Oxygen Demand (COD) which is not in accordance with the environmental quality standards of the Indonesian government. The purpose of this study is to analyze the process capability of wastewater treatment, especially for COD pollutant parameters. Furthermore, several methods are used in this study such as IMR control maps, process capabilities, and Fishbone diagrams. The results show that the COD parameter has an average Cp index value of around 1.03and an average Cpk of approximately 0.44. Therefore, it can be concluded that the wastewater management process still needs to be improved to produce wastewater that conforms to specified standards. This research can be the basis for subsequent research related to improving the quality of wastewater management processes.

Full Text