International Journal of Engineering
Volume:36 Issue: 12, Dec 2023

This paper presents a design and analysis of a Hetero Dielectric Dual Material Gate Underlap Spacer Tunnel Field Effect Transistor, aiming to enhance device performance and overcome inherent limitations. The proposed design incorporates a hetero dielectric gate stack, which consists of two distinct dielectric materials such as high-k-dielectric material as hafnium oxide (HfO2) and low-k dielectric material as silicon dioxide (SiO2). With different permittivity values. By selecting these materials, the gate stack can effectively modulate the electric field distribution within the device, improving electrostatic control and reducing ambipolar conduction. Furthermore, an underlap spacer is introduced in the presented structure to create a physical separation between the source and the channel regions. This spacer helps in reducing the direct source-to-drain tunneling current, enhancing the Ion/Ioff current ratio and reducing the subthreshold swing. Additionally, the underlap spacer enables improved gate control over the tunneling process. The proposed Tunnel Field Effect Transistor design is thoroughly analyzed using numerical simulations based on the technology computer-aided design (TCAD) simulator. Performance metrics as the on-state current (Ion), the off-state current (Ioff), ION/IOFF ratio, drain conductance (Gd) and transconductance (Gm) to assess the device's performance. Therefore, these improvements contribute to lower power consumption and improved circuit performance, making it a promising device for low-power applications.

In this paper, a new online technique for Hall Effect sensor fault diagnosis in brushless DC (BLDC) motor is proposed. The proposed technique is based on phase current waveform analysis and does not need any Hall sensor information. The normalized phases current values are analyzed per and post-sensor fault in every cycle. Using a definition of suitable conditions and threshold values for normalized currents values, all sensor fault types (i.e. set to 0 and 1) could be detected and located online effectively. The main contribution of this paper is introducing an online BLDC sensor fault detection and location technique under low-speed operation and transient conditions. Simulation results show the effectiveness of the proposed technique in all of the sensor faults types diagnosis without any sensor output value information. Two different types of BLDC motors are considered for fault diagnosis using the proposed technique. Simulation results during starting and low-speed operations of BLDC motor are well confirmed by the experimental results.

The wireless sensor networks represent a wide range of potential application, they are composed of a set of energy-constrained sensors used for detecting events and then sending information. In this paper, the novel metaheuristic Dhouib-Matrix-4 (DM4) is enhanced to optimize the coverage repair policies for wireless sensor networks using a mobile robot with different moving speeds. Hierarchically, two conflicted criteria are considered: at first the number of sensors to be visited in time is maximized, then at second, the trajectory distance of the mobile robot is minimized. Therefore, maximizing the lifetime of sensors and minimizing the path of the mobile robot is a challenging issue. DM4 is a multi-start method which uses at each start the novel greedy heuristic Dhouib-Matrix-TSP1 in order to generate an initial basic feasible solution which will be intensified by the new local search technique entitled Far-to-Near. DM4 is applied on several TSP-LIB standard instances from the literature where the moving speed (w) of a mobile actor varied from 0.4 to 1. The performance of DM4 is proven by comparing its results to those generated by the Evolutionary Algorithm (EA). DM4 is developed under Python programming language and a graphical representation of the generated solution is illustrated.

This paper presents a mantle cloak structure to provide a wideband capability to hide a metallic cylinder over a broad span of angles of obliquely impinging plane waves. A bi-layered dielectric structure and a sheet of metasurface are used to enclose the object to be hidden. At first, the scattered field, including co- and cross-polarized components, is analytically formulated using circumferential waves for a multi-layer wrap around the cylinder. A tensor description is also applied to model the impedance of the metasurface for TE and TM waves. Then, a metasurface made of rectangular patches is considered, and its related parameters are optimized to hide a perfect electric conductor (PEC) cylinder. Moreover, a double-layered mantle cloak is presented and numerically investigated using a software package to enhance its cloaking bandwidth. The numerical results show that the clocking bandwidth is enhanced by up to 33% compared to that of a single-layered structure.

According to experts, the use of hydraulic fracturing can increase the oil and gas recovery factor by 10-15%. The Perm Territory belongs to the old oil-producing region of the Russian Federation. To date, more than 60% of the remaining recoverable oil reserves of the fields of the Perm region are concentrated in carbonate deposits. Most of the fields are currently in the late stages of development. These fields, as a rule, are characterized by the presence of undrained zones with residual reserves and low well flow rates. Most of the remaining reserves of the fields are concentrated in low-permeability reservoirs with a high degree of heterogeneity and difficult fluid filtration. Unfortunately, the results obtained in practice do not always correspond to preliminary calculations and do not reach the planned oil production rates. In connection with the above, the problem arises of predicting the effectiveness of hydraulic fracturing operations using mathematical methods of analysis. The effectiveness of hydraulic fracturing is undoubtedly influenced by both geological and technological parameters. In this paper, for the carbonate Kashirsky (K) and Podolsky (Pd) productive deposits of one of the oil fields in the Perm region, using step-by-step regression analysis based on geological and technological parameters, a forecast of the initial oil production rate after hydraulic fracturing was made. There was good agreement between model and experimental results obtained.

By integrating distributed generation resources with the distribution network, the stability and reliability of the distribution network will increase. Due to the advantages of microgrids and the need to implement them, as well as the high cost of installation of distributed generation resources, the existence of a comprehensive and optimal method by considering various aspects of microgrid design is felt more than ever. In this paper, an optimal method for designing microgrids with various conditions is presented. In the first stage, the design of microgrids is discussed on a multi-purpose basis, considering its economic aspects. At this stage, to make a compromise between the economic aspects, the proposed problem is modeled as two-objective functions. In the second stage, the design of distributed generation sources is done in the first level and then in the second level, the optimal placement of switches is done to determine the electrical boundaries of microgrids. In this paper, the discussion of optimal microgrid location based on economic planning using a two-level particle swarm optimization (PSO) algorithm on the standard IEEE 33 Bus network in MATLAB software was performed and for this network, three microgrids with two keys were used.

Numerous methods exist to distinguish between inrush current and internal faults, but these approaches have not yet become practical due to their inherent limitations. As a result, conventional methods, despite their well-known drawbacks, continue to be widely used in practice. In this paper, a new method based on time-frequency analysis is presented for detecting inrush current situations. To do this, a diverse array of scenarios involving a power transformer switching ON and internal fault cases are simulated using the PSCAD/EMTDC software package. Then, a hyperbolic S-transformer is employed to extract a determining index from the simulation results. Finally, a suitable threshold value for this index is computed so that inrush current can be distinguished from fault current by comparing the index with its threshold.  Evaluation of the efficiency of the proposed method using simulation and real data confirms its excellent accuracy. Therefore, it can be used in algorithms for power transformer differential protection to improve their stability during inrush current transients.

One of the most serious causes of disease in the world's population, which kills many people worldwide every year, is heart attack. Various factors are involved in this matter, such as high blood pressure, high cholesterol, abnormal pulse rate, diabetes, etc. Various methods have been proposed in this field, but in this article, by using sparse codes in the classification process, higher accuracy has been achieved in predicting heart attacks. The proposed method consists of two parts: preprocessing and sparse code processing. The proposed method is resistant to noise and data scattering because it uses a sparse representation for this purpose. The spars allow the signal to be displayed at its lowest value, which leads to improve computing speed and reduce storage requirements. To evaluate the proposed method, the Cleveland database has been used, which includes 303 samples and each sample has 76 features. Only 13 features are used in the proposed method. FISTA, AMP, DALM and PALM classifiers have been used for the classification process. The accuracy of the proposed method, especially with the PALM classifier, is the highest among other classifiers with 96.23%, and the other classifiers are 95.08%, 94.11% and 94.52% for DALM, AMP, FISTA, respectively.

Aggressive environment reduces the mechanical and durability-related properties of concrete. In this study, the effects of exposing the concrete containing crumbed tire rubber (CTR) to aggressive environmental conditions, including hydrochloric acid (HCl) is investigated. For this purpose, 5, 10, and 15% of the fine aggregate of the mixing design were partially replaced with the CTR, and then at the age of 7 days, when the concrete reached almost 70% of the initial strength, the samples were placed in water containing 2% HCl for 28 and 90 days. In this study, the effect of using Nano-SiO2(NS) in the rubberized concrete and its behavior in acidic environments by replacing 5 and 10% by weight of cement with NS was also studied. Compressive strength and mass loss were evaluated at 28 and 90 days after casting. The results showed that the detrimental effects of HCl on the compressive strength of concrete significantly increased with an increasing in CTR content of concrete. The results also indicated that the impact of HCl acid on mass loss is improved by increasing the percentage of CTR so that the sample with the 15% crumbed tire showed a 7% lower weight reduction than the control sample.

The purpose of this study is to evaluate the feasibility of using methods for predicting the flow rates of gas wells in fields in Senegal. Accurate forecasting of natural gas production allows you to correctly set the operating mode of wells and design onshore infrastructure. One of the gas fields of Senegal was chosen as the object of study, where deposits were discovered within the exploitation perimeters in the Campanian and Santonian sandstone horizons. Gas formations have high porosity and permeability values, as well as high formation temperatures. Gas well flow rates can be predicted using hydrodynamic models, mathematical models (hyperbolic, etc.) and other methods. This study assessed the possibility of using Arps curves for long-term forecasting of gas flow rate and comparing the forecasting results with actual data. Comparison of Arps curves and actual gas flow rates for wells made it possible to note a discrepancy in the forecast results and actual values of more than 20%. These differences arose for two reasons. Deviations at the initial stage of well operation (6 months), which is associated with the adjustment of the technological operating mode of the well and the establishment of constant parameters of rocks near the wellbore. The second reason is well repairs, which change the properties of rocks near the wellbore. In general, Arps curves of exponential type showed high convergence between predicted and actual values, which makes it possible to use them in predicting the flow rate of gas wells in Senegal.

The study of enzymatic hydrolysis of glucomannan (GM) was currently limited to obtain low molecular weight glucomannan, and was not specifically studied for spray drying feed applications. This research aimed to investigate the effect of enzyme concentration and duration of enzymatic hydrolysis of GM on the characteristics of hydrolyzed glucomannan (HGM). Moreover, the kinetic models of viscosity reduction in enzymatic hydrolysis of glucomannan were also studied. To achieve the goal, the GM was hydrolyzed using various enzyme concentrations (5 to 20 mg/l) for 300 min. Profiles of viscosity, average molecular weight (Mw), degree of polymerization, and antioxidant activity of HGM were observed. The kinetics of viscosity reduction was modeled with 1st-order kinetics, 2nd-order model, and Mahammad's order. An enzyme concentration of 20 mg/l (1% GM solution) was the fastest to reach the desired viscosity for spray drying feed purposes. The model of nth-order was the best fitted to the viscosity reduction with R2 equal to 0.9935, so the constants k = 1.1842 (Pa.s n-1.t)-1 and n = 0.6328 are obtained. The hydrolysis improved the antioxidant activity of HGM as the enzyme concentration increases. This antioxidant result highlighted the advantage of using HGM for coating and encapsulating the active compound which also offers oxidation protection.

The availability of land in Bandung City become a challenge for urban development. Bandung has long been an urbanization destination for Indonesians besides Jakarta, Surabaya, Medan, and Makassar. Currently there was still limited research that explores land values and spatial planning for urban areas. This study aims to develop spatial modeling for land values using a semi-variogram and geostatistical approach in urban areas. Our research was conducted in Bandung City, West Java (Indonesia). Data was selected based on purposive sampling involving 50 land price and 95 building price samples throughout the city. The collected data were then analyzed using 4 semi-variogram models and Ordinary Kriging to derive the spatial distribution of land values. Land value referred to spatial modeling from the geographic information system. The results of the analysis indicated that the semi-variogram stable type was the most suitable model, exhibiting the minimum error by root mean square, mean standardized, root mean square standardized, and average standard error. According to our model, the areas with the highest land values are located close to the city square “Alun-alun”, which is closely associated with government offices, trading areas, defense and security facilities, service areas, education, cultural tourism, and high-density housing. These areas are well known since the Dutch East Indies era. Interestingly, despite the growth pole in Gedebage, the western part of Bandung has higher land values compared to the eastern part. This could be attributed to historical and actual aspects which have had a greater impact on land values than regional plans implemented by the government. Land values management is necessary to guarantee living space as well as to achieve a sustainable city.

Blended learning is a flexible method conducted through face-to-face and online learning. It requires students to learn by attempting the classes physically and allows them to learn virtually at different times and places. It has become more evident and common after the Movement Control Order (MCO) as most of the lectures at the university are carried out in hybrid mode. The blended learning models create problems and opportunities for students as they need to explore and adapt to different lecturers' different blended learning methods in terms of teaching styles, planning, and timing. Therefore, the objective of this research is to investigate the best-blended learning models for an undergraduate engineering course based on student learning style by using the Analytic Hierarchy Process (AHP) method, as it is a big challenge to select the most effective approach for universities to educate, tutor and bring out quality students according to their learning styles. The AHP method is used to aid the students in finding the best-blended learning model based on their learning style. AHP analysis is then conducted to validate and verify its accuracy by comparing it with Visual, Auditory, Read/write, and Kinesthetic (VARK) models. As a result, most students are kinaesthetic learners (72%) based on VARK results, and the face-to-face driver model is the most preferred blended learning model with the priority vector at 31.33% through the AHP analysis. The accuracy of the AHP result is 74% by comparing it with the VARK result. In summary, the data can be deployed in the UTeM blended learning system to improve the course design and student learning experience.

The study of factors influencing the performance of PE pipe against rapid crack expansion is of great significance for the safe use of PE pipe. This paper analyzes the role of each step in the algorithm based on the theoretical basis of random forest, and proposes an improved random forest method based on recursive feature elimination by changing the node splitting rules to address the shortcomings of the random forest classification accuracy. The method is used to analyze the effect of rapid crack expansion of PE pipe in terms of pipe size and wall thickness, impact knife speed, and notched impact strength of simply supported beams. Under the same conditions, the extended crack lengths of DN260, DN150 and DN65 pipes are 197, 164 and 128 mm, respectively, while the crack lengths of PE80 pipes are 24, 210 and 239 mm at impact knife speeds of 10, 15 and 20 m/s, respectively. The higher the notched impact strength of the simple beam, the higher the critical pressure value and the better the RCP resistance. The study of rapid crack expansion of PE pipe based on deep learning algorithm can identify the main internal and external factors affecting the RCP resistance of PE pipe and provide a solid basis for PE pipe life prediction.

This study explores the relationship between a country's level of development and its educational standards, emphasizing the significance of well-equipped universities in ensuring high-quality education. While research on comfort in educational buildings has often focused on individual parameters, such as thermal, acoustic, and visual elements, this paper proposes a new metric that integrates these factors to assess environmental comfort. The research was conducted in six hostel rooms at the National Institute of Technology Warangal (NITW) campus in India, utilizing both objective measurements and subjective surveys. Three single measures were introduced: a thermo-hygrometric index, an audio comfort index, and a visual illumination index, each normalized within a 0-1 range denoting comfort and discomfort conditions. A final total comfort index for each room was established by assigning appropriate weights to the three factors. The findings were compared to the questionnaire responses, evaluating the effectiveness of the proposed methodology. The results indicate a comprehensive assessment of indoor environmental comfort, with acoustic factors showing the least impact on overall comfort conditions. The study recommends equal weighting for thermal, acoustic, and lighting parameters when computing the combined comfort index. The building achieved an overall comfort rating of 0.64 out of 1, indicating a comfortable environment. The study also shows that there is a strong correlation between the new combined comfort index and the results from the questionnaire. `This research contributes a straightforward and integrated approach to gauge comfort levels in educational buildings and lays the groundwork for further assessments of institutional building performance.

In this paper, the impact of the undoped and recessed gate structure on the performance of the silicon carbide metal semiconductor field effect transistor is presented. The importance of the silicon carbide metal semiconductor field effect transistor analyzed using technology computer aided design simulations in 10 nanometer technology. The proposed undoped gate structure has minimized ionized impurity scattering, leading to increased electron mobility and improved carrier concentration. Performance metrics such as drain current, transconductance, subthreshold slope, and cutoff frequency were evaluated and compared with conventional silicon carbide metal semiconductor field effect transistor structures. The proposed device exhibits superior current driving capabilities, enhanced transconductance, and reduced leakage currents, leading to improved power efficiency. Moreover, the recessed gate structure contributes to a significant reduction in short-channel effects, making the device more suitable for high frequency applications. The simulation parameters were calculated and compared with conventional structure with the length of the source and drain in 10 nanometer node. Therefore the drain current of this proposed device has been improved by 68%.

The Strut-and-Tie modeling (STM) technique represents an applicable and valuable method for structural engineers to design disturbed regions (D-regions) of reinforced concrete structures where the assumption of plane sections remaining plane after loading is inapplicable. The most important aspect to guarantee the suitable structural and economic performance of the design is finding a suitable truss-analogy model, leading to the use of a more efficient model in structural buildings. The evaluation of the antisymmetric Strut-and-Tie models (STM) with openings under different concentrated external loads has not been comprehensively investigated in the literature. So, to address this gap, the goal of this paper is to achieve the most efficient reinforcement layout design in antisymmetric reinforced concrete deep beams with openings under concentrated loading using the strut and tie model.  The experimental work was conducted and included (3) antisymmetric reinforced concrete deep beams with openings that were tested under different concentrated loadings (25, 35, and 16 kips for Specimens 1, 2, and 3, respectively) using the strut and tie model. The ANSYS FEM software is used for the initial strut and tie analysis, and the RISA-3D structural analysis program is used to find the internal forces for all members under concentrated external loads in each specimen. The findings of this paper show that Specimen 1 had the highest efficiency of 1.67, while Specimen 3 had the lowest efficiency of 1.31. It can be concluded that the efficient reinforcement layout of the strut and tie model leads to the highest efficiency of the model, regardless of the value of the externally applied load.