MIST International Journal of Science and Technology (MIJST)

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    Characterization of Mechanical Properties of Concrete Recycled Ceramic and Glass Powder Exposed to Elevated Temperatures
    (Research and Development Wing, MIST, 2022-06) Mustafy, Tanvir; Hasan, Md. Maruf; Ahmed Shuvo, Nayeem; Sarwar Mujib, Joarder Md
    Systematic reuse of industrial debris is a crucial component that helps shape the sustainable construction system and green technology. The effective optimization of waste ceramic and glass fines into concrete mixes, as partial replacements of natural sand by volume, has been used in this study to explore the mechanical properties of ceramic recycled aggregate (CRA) and glass recycled aggregate (GRA) concrete at higher temperatures. The study comprises 17 types of concrete mixtures comprised of normal concrete (NC) along with 8 different mixes from both GRA and CRA concrete. In both types of GRA and CRA concrete, the sand replacement (by volume) ratios are similar. This paper highlights NC along with the volumetric replacements of sand as 5%, 10%, 15%, 20%, 25%, 30%, 35%, and 40% in other mixes. A total of 306 cylinders were made whereas 18 cylinders for NC and each group (GRA and CRA) included n=18 cylinders. Selected temperatures were 25°C, 100°C, 200°C, 400°C, 600°C, and 800°C to determine the overall mechanical and chemical alterations in NC and recycled concrete. The study reveals that increasing the addition of recycled glass and ceramic fines improves the overall compressive strength, and tensile strength compared to normal concrete. Higher replacement of ceramic and glass fines reduces the cracks and enhances the durability of concrete. In addition, more strength reduction was noticed in NC with increasing temperatures, while the reduction rate was slower in both GRA and CRA concrete. Furthermore, the study expounds that, by exploiting the ceramic and glass wastes (as fines) into concrete would result in two-way environmental advantages. One is, it would reduce the hazardous ceramic and glass landfills while the other is, it would minimize the frequency of sand mining.
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    Logical analysis of built-in DBSCAN Functions in Popular Data Science Programming Languages
    (Research and Development Wing, MIST, 2022-06) Amiruzzaman, Md; Rahman, Rashik; Islam, Md. Rajibul; Mohd Nor, Rizal
    DBSCAN algorithm is a location-based clustering approach; it is used to find relationships and patterns in geographical data. Because of its widespread application, several data science-based programming languages include the DBSCAN method as a built-in function. Researchers and data scientists have been clustering and analyzing their study data using the built-in DBSCAN functions. All implementations of the DBSCAN functions require user input for radius distance (i.e., eps) and a minimum number of samples for a cluster (i.e., min_sample). As a result, the result of all built-in DBSCAN functions is believed to be the same. However, the DBSCAN Python built-in function yields different results than the other programming languages those are analyzed in this study. We propose a scientific way to assess the results of DBSCAN built-in function, as well as output inconsistencies. This study reveals various differences and advises caution when working with built-in functionality.
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    An Optimized Energy Harvesting Circuit for Low-Power IoT Applications
    (Research and Development Wing, MIST, 2022-06) Barua, Arnob; Rasel, Salauddin
    The concept and development of an independent energy harvesting mechanism functioning intermittently are described in this paper. A power management circuit (PMC) that is self-regulating, an energy scavenging module, a circuit for charging batteries, as well as an electronic load are all a component of the system that has been proposed. This proposed circuit is designed to attain a fixed output power with a diverse input range. In the unavailability of an additional voltage supply, the PMC can react, maintain, and smartly control the electronic load's power supply. The self-powered energy accumulating technique is expected to be used in situations when supplied power is inadequate to drive the load properly, such as Internet of Things (IoT) applications. IoT is a dispersed architecture of reduced-power, limited-storage, lightweight, and nodes that are adaptive. The majority of embedded IoT devices and low-power IoT sensors are driven by short-life batteries that must be replaced every few years. This procedure is expensive and efficient energy regulation could be critical in enabling energy savings for connecting IoT devices. Experiments with the proposed PMC show that the voltage stored in the capacitor remained mostly fixed at 3.3V at widely diverse inputs that vary from 850mV to 4V. At 3.5V input voltage, a peak efficiency of 88.67% is achieved while the load resistance considered is 230Ω.
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    Cascaded Fuzzy Logic for Adaptive Cruise Control
    (Research and Development Wing, MIST, 2022-06) Simic, Milan
    Application of fuzzy logic is a powerful approach that could be applied in a large number of disciplines, starting with engineering control systems, as shown here, but also in other business areas. After a short introduction to fuzzy logic, its application for adaptive cruise control (ACC) is presented. ACC is a driver assistance feature that deals with the problem of speed control, while keeping the safe distance from the vehicle ahead. In the hierarchy of autonomous vehicles autonomy levels, as defined by Society of Automotive Engineers (SAE) International, adaptive cruise control appears in the vehicles at the level 1 and above. We developed a fuzzy logic controller where controlled variables are speed and distance. Input variables include weather conditions, style or mode of driving, vehicle speed and steering angle. A large number of input variables improve control but lead to a large fuzzy rules table. Because of that, in the design presented here, a tree of connected fuzzy inference systems (FIS) is applied. Fuzzy inference systems with a smaller number of variables are developed, algorithms explained, rule base defined, and obtained control surfaces presented. This approach requires less processing time enabling real time applications. Since the rules are defined based on drivers’ experiences, fuzzy logic control systems make decisions in the same way as humans do, i.e., as experience drivers. This paper gives a comprehensive presentation of a novel cascaded fuzzy system development. This novel design also involves algebraic subtraction performed through a FIS subsystem.
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    Physical and Strength Properties of Cements Manufactured in Bangladesh: A Case Study
    (Research and Development Wing, MIST, 2022-06) Ahmed, Khondaker S.; Asef, Mohammad F.; Ahmed, Mahfuj
    This study investigates the physical qualities and strength properties of representative cements manufactured by different brands in Bangladesh. The physical and strength properties such as normal consistency, initial and final setting time, density, specific gravity, fineness, and compressive strength of cement mortars as well as concrete cylinders were investigated experimentally. Using CEM II/B-M type cement, a total of 300 test specimens are prepared to determine those parameters. In this case study, specimens were prepared from ten different representative cement industries of Bangladesh and tested as per ASTM specifications. The experimental result shows that the physical and strength parameters of nearly all the representative cement samples are within the ASTM recommended ranges that ultimately proofs the quality of Bangladeshi Cement. The relationship between mortar and concrete strengths from the same batch of cement has also been investigated. Besides, a regression analysis has been conducted to find relationships between the concrete strength and their age of curing. The influence of initial and final setting times on concrete strength is also investigated. This study also provides the relationships between compressive strengths, between mortar and concrete cylinders at different ages. These age dependencies of concrete strength will help to predict the actual concrete strength at the early age of curing which may ensure faster construction work.
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    Assortment of Dispatch Strategies with the Optimization of an Islanded Hybrid Microgrid
    (Research and Development Wing, MIST, 2022-06) Shezan, Sk. A.; Ishraque, Md. Fatin; Paul, Liton Chandra; Sarkar, Md Rasel; Masud Rana, Md; Uddin, Moslem; Hossain, Mohammad Belayet; Asaduzzaman Shobug, Md; Hossain, Md. Imran
    In this work, the optimization of an off-grid micro-hybrid system is evaluated. This is conducted with the estimation of the proper sizing of each element and the steady-state voltage, frequency, and power responses of the microgrid. Kangaroo Island in South Australia is considered to be the test case location and the grid incorporates solar PV (photo-voltaic), diesel generator, battery storage, and wind turbine. Optimal sizing of the studied microgrid is carried out for four various power dispatch techniques: (i) cycle charging (CC), (ii) generator order (GO), (iii) load following (LF), and (iv) combined dispatch (CD). The proposed off-grid micro-hybrid is optimized for three performance indices; minimal Levelized Cost of Energy (LCOE), CO2 emission, and Net Present Cost (NPC). Using iHOGA (improved hybrid optimization by genetic algorithm), microgrid optimization software, all the above-mentioned dispatch strategies have been implemented and following this, MATLAB/Simulink platform has been used for the steady-state studies. The results show that the LF strategy is the utmost optimum dispatch technique in terms of the studied performance indices i.e. considering the optimal size and voltage and frequency responses. The results obtained from these studies provide a pathway for the estimation of the resource-generation-load combination for the islanded off-grid microgrid for its optimal operation with the various dispatch strategies.