International Journal of Engineering
Volume:35 Issue: 4, Apr 2022

Effects of two admixtures , calcium carbonate powder (CCP) and micro silica gel (MSG) on self-compacting concrete (SCC) properties, such as workability, compressive strength, and durability are investigated. Results, show that, in some cases, concrete with MSG is unable to provide a stable condition, although flowability is higher. Experimental results indicate that the effect of CCP on sustainability, strength and durability of mixture is remarkable. Combo mix design is introduced to benefit from the positive characteristics of two admixtures. Results of decision making method show that this mix can be considered as a proper sample along with the sample containing the optimal dosage of CCP. Moreover, this method indicates the optimal dosage of CCP is 31.25%, which leads to the best improvement in characteristics of fresh and hardened concrete. In practical engineering, economic analysis demonstrates that using CCP is more cost effective, because is accessible and inexpensive in Iranian market.

Lane detection is amongst the most important operations during the automatic driving process. This process aims to detect lane lines to control the vehicle’s direction in a specific lane on the road and it can be effective in preventing accidents. Besides being online, the most requirement for lane detection methods in automatic driving is their high accuracy. The use of deep learning to create fully automated systems in lane detection has been done extensively. Automated learning-based methods used for road lane detection are often of supervised type. One of the disadvantages of these methods, despite their excellent accuracy, is that they need a set of labeled data, which limits the development procedure of the lane detection system, and most importantly establishing a standard set of labeled data is very time-demanding. The recommended solution is to use appropriate learning approaches that can be used to achieve the relative accuracy of the supervised approaches and to improve their speed. It also enables us to use different datasets without a constraint label that the tagged dataset would create in the algorithm development relative to the new dataset. In this research, we present an automatic semi-supervised learning method using deep neural networks to extract the data of lane lines, using labeled (mask for detected lines) and unlabeled datasets. The results demonstrate the suitable accuracy of the adopted method according to the proposed approach and also improves its computational complexity due to the significant reduction in the number of teachable network parameters.

This work is dedicated to survey the structural reinforced concrete's behavior horizontally curved box beams with and without opening. Seven horizontally circular box beams were examined in the experimental work, one without opening, three with vertical opening and three with transverse opening. The test program includes the main variables; direction of opening, location of opening through profile of curved beams (effect of combination of internal forces). The beams were tested as a continuous beam with two spans, each span represents a quarter circle and under the action of two point loads each load located at top face of midspan of beam. The findings indicate that the ultimate load capacity was decreased for all specimens (CB2.V37, CB3.V60, CB4.V82, CB5.T37, CB6.T60 and CB7.T82) by about (5%, 11.5%, 1.5%,1.5%, 46.4% and 18.66%) respectively, compared to the control CB1. When compared with the control specimen CB1, all specimens were indicating an increase in Service deformations in terms of deflection and twisting angle at mid-span of the circular beams. The ductility was deteriorated for all specimens with opening (CB2.V37, CB3.V60, CB4.V82, CB5.T37, CB6.T60 and CB7.T82), as a percent were about (13.88%, 15.3%, 19.62%, 0.5%, 0.5% and 13.88%) respectively, compared with that of control specimen CB1. Generally, the specimens containing opening were shown a clear degradation in its stiffness.

Radio refractivity is very crucial in the optimal performance of radio systems and is one of the attributes that affect electromagnetic waves in the troposphere. This study presented a comparison of different variants of recurrent neural networks to predict radio refractivity index. The radio refractivity index is predicted based on forty-one years (1980-2020) metrological data obtained from the MERRA-2 data re-analysis database. The refractivity index was computed using International Telecommunication Union (ITU) standard. Explanatory data analysis (EDA) method was used for better perception. Long- and short-term Memory (LSTM), Bi-Long- and short-term Memory (BiLSTM) and Gated Recurrent Unit (GRU) neural networks were trained to learn features from the dataset. The refractivity index for the year 2021 was predicted based on the knowledge learned from the previous forty-one years. The trained model’s predictions and estimation were validated against each other. The correlation refractivity index was categorized into strong, weak and no correlation. Rainfall, relative humidity, and pressure fall in the first category, the temperature falls in the second category while wind speed falls in the last. The true future and predicted values of the radio refractivity index are close with GRU performing better than the other two models (LSTM and BiLSTM) which proves the accuracy of the proposed model. In conclusion, the proposed model can establish a radio refractivity status of locations at a different time of the season, which is of great importance in the effective design, development, and deployment of radio communication systems.

This research looks at how photovoltaic (PV) cells generate energy in different weather conditions. Photovoltaic power today plays a key role in the production of energy and satisfying the needs of consumers all over the world. The PV cell's ability to generate electricity was entirely dependent on sunshine and temperature fluctuations in the environment. Several researchers are working on a variety of MPPT methods for a photovoltaic system. Outdated MPPT techniques are unable to withstand a dramatic change in weather conditions. The fundamental purpose of this study is to associate the numerous unadventurous and clever controllers for MPPT of the PV system, such as the PSO, GA, and CNFF. The MATLAB environment was used to create and simulate the recommended intelligent controller for MPPT in the PV system. Furthermore, the aforementioned findings like Voltage, Current and Power with respect to different irradiance and temperature are compared and evaluated. The performance of the above-mentioned topologies has been related to the optimum intelligent controller for the PV system and concluded that the CFFNN gives better efficiency with minimum time required to extract.

A convenient family member of composite columns is concrete filled double skin tube (CFDST); it contains two tubes of concentric steel and also shell concrete that there is between them. The superior or equal potential offering characteristics of CFDST columns are more than counterparts of filled steel tubes of classical concrete (CFST). The purposes of the present study are to provide experimental investigation results into the prestressed load-carrying capacity of CFDST columns. Here, an innovative and novel technique is used to confined concrete prestressing, in which the fresh concrete is compressed for a short-run duration. Sixty-four total specimens were tested with various outer thickness (to) and diameter (Do), inner thickness (ti) and diameter (Di), and also CFDST columns of concrete strength that resist axial compression. The experimental results support that the present technique prestressed confined concrete, and it demonstrates that CFDST specimens' load-carrying capacity enhanced significantly. The development of an accurate and simple formula for the short circular of CFDST columns' ultimate axial strength prediction in terms of active/passive confinement, concrete compressive strength, Di/ti, and Do/to is the other purpose of the present study.

Multiple criteria decisions making (MCDM) techniques are employed widely by decision-makers for ranking the potential alternatives under conflicting environments to select the best one for different industrial problems. Present work employed a modified Simple Additive Weighting (SAW) method to solve different decision-making problems in the manufacturing industry such as industrial robot selection, flexible manufacturing systems selection and, non-traditional machining processes selection respectively. The proposed methodology is simple and involves lesser mathematical complexity. The ranking obtained by the proposed modified SAW method corroborates well with other popular MCDM methods like MOORA, MABAC, TOPSIS and AHP for solving similar problems. It indicates the robustness of proposed method. However, the proposed method is better compared to those methods through its simplicity, lesser computational complexity, and lesser computational time. Further, sensitivity analysis indicates stability of the method. Being generic the method can be applied for solving problems related to ranking and selection in any societal segment.

The paper presents a reliability analysis of a two-span reinforced concrete beam, taking account of random variations in cross-sectional dimensions, area and position of reinforcement for sagging and hogging bending moments, material strengths, loads and model uncertainties. In addition, the limit state functions for the statically indeterminate beam were derived, considering the static equilibrium requirement after the moments were redistributed as well as the codified allowable limit for the adjusted moment at each beam section. A large number of Monte Carlo simulations were performed in which the basic variables were modeled with normal, lognormal and Gumbel distributions. When the elastic moment distribution was used in evaluating the beam reliability, the two-span beam behaved as a series system with three critical nodes located at the interior support and midspan sections. The probability that the system had at least one overloaded node was greater than the failure probability of an individual node. However, considering moment redistribution made it possible to reduce the amount of reinforcement whilst maintaining the reliability of the beam. When the reinforcement area was reduced by 26% at the support section or 14% at the midspan sections, the failure probability was predicted to be 6.90E-5, which is deemed acceptable for a 50 year reference period.

Planned Special Event (PSE) is a public activity that has a defined location and time and has an influence on transportation system operations as a consequence of increases in travel demand or decreases in road capacity. Apart from the event itself, PSEs might generate additional activities based on location, time and duration of the event, and individual preferences. This paper focuses on the interim activities of soccer spectators in Istanbul. This paper is motivated by the mostly disregarded but significantly important demand for these activities by jointly analyzing the arrival time and location preferences for the interim activities carried out before the main activity. For this aim, a joint logit model capturing the factors influencing the arrival time and location choice collectively within the PSE circumstances is estimated. In this estimation, each trip and behavior of spectator groups are modeled separately. According to the results of the models, one significant and interesting finding is the behavioral differences of supporters of different teams which is mostly influenced by the activity opportunities present in the surrounding of the venues. Last motorized trips of the Besiktas and Fenerbahce’s spectators end at the sub-centers in general, while the spectators of the Galatasaray prefer the stadium as their final destination. Moreover, league matches being on weekdays or weekends does not have a statistically significant effect on the choice of arrival time and location of the spectators. The findings provide useful information that might assist event organizers and decision-makers especially in planning special events.

Due to the ease of access to platforms that can be used by forgers to tamper digital documents, providing automatic tools for identifying forged images is now a hot research field in image processing. This paper presents a novel forgery detection algorithm based on variants of Benford's law. In the proposed method, Mean Absolute Deviation (MAD) feature is extracted using traditional Benford's law. Also, generalized Benford's law is used for mantissa distribution feature vector. In addition to Benford's law-based features, other statistical features are used to construct the final feature vector. Finally, support vector machine (SVM) with three different kernel functions is used to classify original and forged images. The method has been tested on two common image datasets (CASIA V1.0 and V2.0). The experimental results show that 0.27% and 0.21% improvements on CASIA V1.0 and CASIA V2.0 datasets were achieved, respectively in detection accuracy by the proposed method in comparison to best state-of-the-art methods. The proposed efficient algorithm has a simple implementation. Moreover, on the basis of Benford’s law rich features are extracted from images so that classification process is efficiently performed by a simple SVM classifier in a short time.

There are several attempts to improve surface characteristics of biomaterials with thick film coatings. In this research, a class of protective coating layers of bi-layered Hydroxyapatite (HA)/Al2O3-SiO2 (with 10, 20, 30 %wt SiO2) were deposited on titanium (Ti) surfaces by plasma spray technique. The surface features of the applied coating layers were evaluated in detail to confirm the effectiveness of the technique for further biomedical applications. The results demonstrated that uniform and bi-layered plasma sprayed coatings can be successfully prepared through the optimization of engineering parameters. Also, it was found that the roughness of the bi-layered coatings increases with increasing the number of coating layers. The corrosion behavior of the coated and uncoated samples was comparatively investigated using electrochemical tests. The measured current densities (icorr) for HA, (HA)/Al2O3-SiO2 (with 10, 20, 30 %wt SiO2) were 0.27μA/cm2, 0.28 μA/cm2, 0.23 μA/cm2, 0.79 μA/cm2, respectively. According to the results, corrosion resistance of samples with 20% SiO2 is significantly improved compared to the single-layer HA and bare Ti. The outcomes of FESEM results revealed that porosity and cavities related to evaporation of adhesive PVA and it is confirmed by increasing the percentage of silica to more than 20%, porosity has increased. In conclusion, the proposed coating system showed promising abilities for future biomedical applications. It could be optimized and improved by changing the structural characteristics of the substrate, chemical composition and porosity of the coating layers.

In this paper, the normal exergy scrutiny (NES) and advanced exergy scrutiny (AES) of a waste heat recovery (WHR) system was performed. The proposed system contains a dual-loop organic Rankine cycle (DORC) which recovers the available waste heat of the intake air, exhaust gas, and coolant streams of a 12-cylinder heavy-duty stationary diesel engine. A well-known method of the AES called the thermodynamic cycle approach is utilized to determine each component exergy destruction parts namely exogenous/endogenous, unavoidable/avoidable, etc. Results showed that 59.04 kW from the 258.69 kW total exergy destruction rate of the system could be eliminated (22.82% of the total exergy destruction rate). The total avoidable exergy destruction part of the low-temperature loop accounts for 46.62 kW, which indicates that it requires more attention than that of the high-temperature loop by 12.42 kW. Furthermore, it is revealed that to enhance the overall productivity of the system, there is a relatively significant difference in priority order regarding the improvement of system components. The AES has proposed this ranking for improvement priority of components: condenser, expander 2, expander 1, respectively. While the NES has specified the priority as the evaporator 1, condenser, expander 2, respectively.

Identification of combined power quality disturbances in the modern power systems by considering the development of different types of loads and distribution generations has become increasingly important. The novelty of this paper comes from the accurate and fast identification of the combined power quality disturbances in the presence of different distributed generations and loads such as photovoltaic cell, wind turbine with doubly fed induction generators, diesel engines, electric arc furnace, DC machine, 6-pulse and 12-pulse rectifier loads. In this paper, the features are extracted using variational mode decomposition, just from voltage waveforms. To reduce the redundant data, dimension of features vector, and time, the Relief-F method and correlation feature selection method are applied on the extracted features and these two methods are compared together. In this paper, the K-nearest neighbors classifier is used to classify the multiple power quality disturbances.  To verify the effectiveness of the proposed method, different scenarios such as misfiring, variation of sun radiation and wind speed, entrance and exit of loads, capacitors and distributed generators, different fault at the grid in half-load to full-load were simulated. This method can be used as an added algorithm for smart metering in modern and smart power systems.

Duplex stainless steels (DSSs) find increasing use as a substitution to austenitic stainless steels in oil, gas and petrochemical industries, particularly in aggressive environments. Duplex stainless steels with appropriate controlled ferrite-austenite balance combine the attractive properties of excellent strength, general corrosion performance and adequate weldability. All the welding joints subjected to the regulation must be controlled before commissioning the pipeline and even before hydrostatic tests; all not acceptable defects detected with non-destructive testing (NDT) control methods must be eliminated. In some cases, several successive repairs are often preferred to part replacement in the pipeline due to lack of experience of the welder performing the repairs or lack of expertise of the controller ensuring the application of the welding procedure. The purpose of this work is to study the influence of repairs on the same welding joint on the microstructure and the mechanical properties of the heat-affected zone in duplex stainless steel with 22% chromium welding joints. For this purpose, a cylindrical specimen is prepared, on which the various repairs are carried out. Then, an NDT control and the main mechanical and micrographic tests are conducted. The results obtained after four repairs revealed that the multiple repairs made to the same joint did not affect the quality of the welding joints.

In order to realize the behavior of two-phase flow in an inclined rectangular channel with 90̊ bend for various vertical lengths, an experimental investigation has performed. The test section (a chanel with 30 m length) contains two horizontal parts and a middle vertical section. Three vertical lengths of 50, 100 and 150 cm were utilized along the test section. The cross section of the rectangular channel is 10 cm × 15 cm. Air and water were the fluids used in this work. Various flow patterns are created by varying the volumetric flow-rates of gas and liquid; the air and water flow rates were in the range of 2 to 10  and 34 to 235 , respectively. The high speed video system was utilized to achieve image subsequence of the flow under various conditions. The effects of vertical length on flow regimes and pattern transition borders are examined. According to the flow visualization, no vortex was observed in the vertical section. The significant flow regime in the vertical section is churn flow regime. It is concluded that the flow pattern structures are not greatly affected by changing the vertical length.

The present paper investigates the stress distribution in structural elements reinforced with laminates and subjected to axial loads. The proposed analysis provides an analytical solution for the shear stress distribution between the substrate and the reinforcement, and for the normal stresses in the cross-section of the reinforcement. The stress analysis assumes a linear elastic mechanical behaviour of the adherents. The solutions obtained are applied to the problem of the elastic stability of a beam/column supported at its ends. The manifestation of the buckling phenomena leads to the failure of the structural el-ement for loads lower than the characteristic strengths of the materials. In particular, the critical load represents the watershed value between the purely compressive and flexural behaviour of the element considered. In the case of stiff substrate, the buckling phenomenon leads to delami-nation of the reinforcement in the compressed area. Since buckling is an elastic problem, the stress distribution in the elastic range is used here to determine the value of the delamination length of the reinforcement at the critical load. In this way an analytical analysis which may be useful in the design phase of the reinforcement is proposed.

In the present study we have investigated the dielectric properties such as dielectric constant (ε'), dielectric loss (ε"), real part of electrical modulus (M'), imaginary part of electric modulus (M") and AC electrical conductivity, (σac) in wide range of applied voltage, temperature and frequency for Ni/n-TiO2/p-Si/Al heterojunction. A nanocrystalline TiO2 layer was grown on p-type boron doped silicon in oxygen-controlled environment using optimized KrF excimer laser. Ohmic contact of pure nickel and aluminum metals was made on TiO2 and silicon respectively, with thermal coating system. The characteristics obtained with the help of conductance-voltage and capacitance-voltage measurements also known as impedance/admittance spectroscopy. The studied parameters are found to be very sensitive to frequency, temperature and voltage. The restructuring and reordering of interface state density due to temperature variations and interfacial polarizations due to frequency variations collectively result the observed changes in the and . With an increase in frequency AC conductivity and electrical modulus also increases. The relaxation mechanism can be observed in the complex electrical modulus analysis. The thermally activated conduction process was indicated by the frequency dependent AC conductivity at different temperatures. Using power law, the AC conductivity was analyzed and found to increase with temperature, applied voltage.

Collapsible soils are soils susceptible to large volumetric strains when they become saturated. Numerous soil types fall in the general category of collapsible soils, including gypseous soil which is characterized by relatively low density, appreciable strength and stiffness in the dry state, but is susceptible to significant deformations as a result of wetting. The aim of this study is to investigate the effectiveness of curing period time of carbonation on magnesium oxide stabilization of gypseous soil. In this research, magnesium oxide is used to improve a collapsible gypseous soil by using (0, 5, 10 and 15%) with two relative densities (35 and 75%) and carbonation at different carbonation periods (0, 1, 3 and 24 hours). Conventional collapse tests, single oedometer and double odeometer and modified collapse test are used in this research to investigate the effect of carbonation periods on the improvement of the soil. The modified collapse test apparatus is used. The results illustrated that the collapse potential decreased more than 65% and 55% for the carbonated soil without treatment for conventional tests and modified collapse test, respectively. A decreased about 55% for treated soil with 10% magnesium oxide and carbonated for 3 hours for both of conventional tests and modified collapse test. The carbonation period time is used to accelerate the improvement of the soil as well as decreased the collapse potential and the results showed that no clear change in collapse potential for the period time more than 3 hours.

Every year, many newborns lose their sight to retinopathy of prematurity (ROP) worldwide. Despite its high prevalence and adverse consequences, periodic examinations can effectively prevent it. The use of an intelligent system enables physicians to avoid medical mistakes while examining newborns. The optic disk (OD) is an integral part of the retina for grading the severity and progression of ROP. Due to the uneven brightness and lack of a defined OD border, the use of retinal images of infants is very challenging for OD diagnosis. This paper provides an innovative model of OD segmentation based on attention gate. Initially, the images were collected and preprocessed and inputted into a novel deep convolutional neural network consisting of attention in skip connections. The architecture is comprised of a two-stage convolutional network. Different outputs are obtained from two individual branches of the original image and image features in the first stage. The outputs were concatenated to transfer into the post-processing stage to identify the area related to the OD. The final results based on the Dice coefficient (Dice) and the Intersection-Over-Union (IoU) were 94.22% and 86.1%, respectively.

The Universal Filtered Multicarrier (UFMC) waveform technology is one of the promising waveforms for 5G and beyond 5G networks. Owing 2N-point Fast Fourier Transform (FFT) processor at the UFMC receiver, the computational and implementation complexity is two times more than the conventional Orthogonal Frequency Division Multiplexing (OFDM) receiver system. In this paper, we proposed a simplified UFMC receiver structure to reduce computational complexity as well as hardware requirements. The received UFMC symbol simplified exactly to its equivalent after performing 2N-point FFT and decimation operations. In which, the mathematical model of the frequency-domain UFMC signal is rederived after processing through 2N-point FFT and decimator, and the simplified signal is generated with an N-point FFT. Accordingly, the 2N-point FFT processor and decimator are replaced with a single N-point FFT processor. This approach reduces the 50% computational complexity at the FFT processor level hence the hardware and processing time. The computational complexity of the proposed receiver model is approximately equivalent to the OFDM receiver. Additionally, analyzed the mathematical model for the simplified UFMC receiver and the comparative performance of the UFMC system with the conventional model.

Nowadays, reducing the self-weight of structures and vibration problems is the primary goal for design requirements in most civil constructions. Two-point loading and harmonic loading tests were conducted to examine the strength and serviceability of high-strength reinforced concrete one-way ribbed slabs. Six slabs were cast and tested. The behavior of cracking, deflection, and vibration was investigated. The experimental results showed that using high strength-lightweight concrete (HSLWC) instead of high strength-normal weight concrete (HSNWC) in constructed one-way ribbed slab led to a decrease in the density by 19.31%, the strength by 17.70%, and ultimate deflection by 17.33%. Although the addition of steel fibers to HSLWC led to an increase in the density of concrete its addition enhances the load-deflection relationship and ultimate load for slab specimen which reduced the reduction in strength by 14.49%. Furthermore, ductility index, stiffness, and toughness index for ribbed slab specimens with steel fibers showed better behavior than those without steel fibers. The HSNWC gave a negative impact on the vibration of the one-way ribbed slab at both operation frequencies (25 and 50) Hz, while using HSLWC with and without steel fibers, led to reducing the vibration effect by (30.11and 30.68) % and (15.26 and 20.25) % at 25Hz and 50Hz, respectively.

To cope with the strong vibration of a supporting structure excited by external loads under operating conditions, and in order to achieve the purpose of vibration reduction by structural optimization through modal modification, a modal modification method was proposed, through structural vibration theory. Subsequently, the search performance of an improved particle swarm optimization method was analyzed before conducting a case study on the structural optimization. Finally, aiming at the problem of strong vibration of gun mount at the time of firing, a finite element model of the gun mount was constructed and the type and natural frequency of the gun vibration in a free state was analyzed. Meanwhile, taking the thickness, height and width of the stiffening structure of the bracket as the design variables, combined with the improved particle swarm algorithm, an optimized mathematical model was developed with the first-order natural frequency of the gun mount as the objective function. The secondary development of Abaqus finite element software by using Python is used as a tool to calculate the optimization model. By virtue of optimation, thickness, width and height of the stiffening structure are 156.4mm, 453.7mm and 238.9mm at the range of [100,600]mm, [100,700]mm, [100,700]mm, respectively, and the base frequency of the gun mount has been increased by 11.3%. The effect is remarkable.

Recently most of the documents are authenticated by using a latent fingerprint impression. Examples of such documents are property registration, banking transactions, insurance documents, etc. The fingerprint-based document retrieval (FPDIR) has emerged to provide an easier way of accessing, browsing, or searching such document images. This paper proposes efficient fingerprint-based document image retrieval by employing multi-resolution Histogram of Oriented Gradient (HOG) features. The preprocessing technique presented in this paper employs a combination of top-hat and bottom-hat filtering operations to enhance the detected fingerprint image. Multi-resolution HOG features are constructed from horizontal, vertical and diagonal directional components of the enhanced fingerprint image. Finally, a standardized Euclidean distance metric is used as a tool for matching, ranking and retrieval of the document images. The proposed system is assessed by experimenting with a dataset of 1200 images. The precision and recall results obtained using the proposed research work have given an improvement of 8% to 14% in retrieval performance compared to earlier methods.

In this 21st century, various materials like metals, alloys, and composites are available for different industrial applications. Composite materials are gaining popularity due to their enhanced mechanical properties over other materials. However, for continuous improvement in the properties of these materials, different research groups are constantly involved in it. In this research paper, the focus is to review the mechanical properties like hardness, tensile strength, flexural strength, impact strength along with surface characteristics like wear resistance of AMMC’s. As per the available literature, liquid state processing is more popular than solid-state processing due to the better dispersion of the reinforcement particles in the matrix materials. Stir casting is mostly used liquid state processing method because of its ease and the overall low cost of production. It has been noticed that the mechanical and surface characteristics of AMMC’s can be improved by adding different reinforcement particles in small percentages (usually 0.5-20%). It has been observed that hardness, tensile strength and flexural strength for mostly used AMMC’s ranges from 38-99.6 HV, 100-478 MPa and 199.52-430 MPa respectively. The research paper also included the influence of various working parameters on the wear rate of AMMC’s. It is noticed that wear loss for AMMC’s generally varies from 0.0050-0.004 g. The impact resistance is a crucial parameter in the study of AMMC’s used for aerospace and automotive applications and it has been noticed that its value for popular AMMC’s varies from 3.6-38 J.