Hamedan University of Technology
  • Hamadān, Hamedan, Iran
Recent publications
Background Breast cancer (BC) has been reported as one of the most common cancers diagnosed in females throughout the world. Survival rate of BC patients is affected by metastasis. So, exploring its underlying mechanisms and identifying related biomarkers to monitor BC relapse/recurrence using new statistical methods is essential. This study investigated the high-dimensional gene-expression profiles of BC patients using penalized additive hazards regression models. Methods A publicly available dataset related to the time to metastasis in BC patients (GSE2034) was used. There was information of 22 283 genes expression profiles related to 286 BC patients. Penalized additive hazards regression models with different penalties, including LASSO, SCAD, SICA, MCP and Elastic net were used to identify metastasis related genes. Results Five regression models with penalties were applied in the additive hazards model and jointly found 9 genes including SNU13, CLINT1, MAPK9, ABCC5, NKX3-1, NCOR2, COL2A1, and ZNF219. According the median of the prognostic index calculated using the regression coefficients of the penalized additive hazards model, the patients were labeled as high/low risk groups. A significant difference was detected in the survival curves of the identified groups. The selected genes were examined using validation data and were significantly associated with the hazard of metastasis. Conclusion This study showed that MAPK9, NKX3-1, NCOR1, ABCC5, and CD44 are the potential recurrence and metastatic predictors in breast cancer and can be taken into account as candidates for further research in tumorigenesis, invasion, metastasis, and epithelial-mesenchymal transition of breast cancer.
Major depressive disorder (MDD) is conventionally diagnosed through a questionnaire. Since approaches to diagnose MDD may lead to inaccurate diagnoses, many studies have presented electroencephalogram (EEG)-based machine learning techniques. The present paper introduces a deep learning approach based on image construction from EEGs. Two images are constructed from EEGs based on spectral and functional connectivity features. Afterward, the constructed images are applied to a two-stream convolutional neural network, and the outputs are concatenated. Finally, the concatenating result is applied to a sequential model of long–short-term memory, fully connected, and softmax layers to classify each sample into the MDD and healthy control (HC) classes. To validate the proposed approach, a public EEG dataset was used consisting of EEG data recorded from 34 MDD patients and 30 HC-matched participants. This framework obtained an AC of 98.03%, SE of 98.85%, SP of 97.19%, F1 of 98.07%, and FDR of 2.69% for the random splitting assessment method and achieved an average AC of 99.11%, SE of 98.97%, SP of 99.25%, F1 of 99.13%, and FDR of 0.71% using a 10-fold cross-validation process. Considering the accurate performance of the proposed method, it can be developed as a computer-aided diagnosis tool to diagnose MDD automatically.
In this paper, the effect of tunnel excavation and Metro station has been investigated on adjacent bridge foundation with two objectives: investigation of the subsidence by tunneling and the effect of tunnel excavation on the behavior of adjacent bridge foundation by Plaxis 3D finite element software. Therefore, the tunnel of Line 3 of the Tehran Metro near Nobonyad Square, which passes through a pier of the Sadr Bridge to the Nobonyad Metro Station, was selected. To explore the effects of the pile length on settlement, the axial load and bending moments of three scenarios, including piles with a length of 37 m, piles with a length of 47 m, and no piles, were evaluated. It was found that settlement above the station and tunnel reduced near the bridge foundation, suggesting a stiff foundation. To study the effects of the tunnel on adjacent piles, the changes in the axial loads and bending moments of the piles under tunneling and station construction and then in two different models. The post-tunneling axial loads of the pipes showed significant differences from the pre-tunneling values. The results revealed that the axial pile load was slightly higher at a pile length of 47 m than at a pile length of 37 m. As with the axial load, the bending moment increased after tunneling. A comparison of the bending moment between the two models indicated that a 10-m reduction in the pile length would not change the behavior and bending moment of the piles.
The tensile strength and cracking behavior of layered rocks in a tensile stress field are one of the most significant characteristics of rock masses, which may strongly affect the stability of rock structures. The study presented here investigated the effect of layer spacing and inclination angle on the indirect tensile strength, crack development, failure pattern, and contact force chain of layered disks under diametral loading using experimental and numerical investigations. Numerous experimental models made from plaster were examined under diametral loading, and a two-dimensional Particle Flow Code (PFC2D) was adopted for in depth simulation of the failure process. Both numerical and experimental results were found to be in great agreement and showed that the increase in the layer orientation up to 15° results in the peak in the tensile strength followed by a decrease. Specimens with the spacing ratio (SR) of 0.5 and 0.1 showed the highest and lowest tensile and compressive stresses at the disk center, respectively. Moreover, the numerical analysis indicated the formation of three failure pattern types: TL, PB, and TL-PB. Tensile cracks mainly formed in the direction of diametral loading, and their maximum number formed at 15° and SR = 0.5. Additionally, the shear ones formed in a conjugate system and had negligible numbers. The analysis of the contact force chain showed that the layers do not affect the compressive force chain at α < 45° but at higher angles, the stronger layers transfer compressive force. However, when α ranges from 0° to 30°, tensile forces are distributed in stronger layers, and with an increase in α, the concentration of these forces in these layers diminishes and the forces are reoriented in the direction of diametral loading
The room-and-pillar technique is a self-supporting mining method in which part of the ore is left unmined as pillars. To increase the mining efficiency, the pillars are later recovered partially or completely. This research aims at evaluating and comparing four methods of pillar recovery, namely, ‘pocket and wing’, ‘open ending’, ‘split and fender’, and ‘Christmas tree’ which are of particular importance. The performance of these methods of pillar recovery in the Tabas coal mine was evaluated by numerical modeling. To do this, a series of three-dimensional simulations were carried out in which the pillars were excavated according to the sequences specified by each method of recovery. The behavior of chain pillars, barrier pillars, and the roof was monitored and compared for the different cutting sequences. Using the shear strength reduction technique, the safety factor values were calculated during the different recovery methods until the verge of roof caving. The results revealed that the method of split and fender leads to a softer drop of the safety factor, and consequently, more controlled caving of the roof.
In this article, the effects of porosity and its geometry on tensile features of concrete were investigated, using the Brazilian test and three dimensions PFC model. In the first step, the PFC sample was calibrated by indirect tensile lab outcomes and uniaxial compression test outputs. In the next step, indirect tensile tests were done on the models consisting of various pore shapes. Cylindrical models consisted of internal pores with different shapes such as rectangular, circular, horizontal notch, and vertical notch. The diameter and or the length of these porosity changes in various values, i.e., 10 mm, 20 mm, and 30 mm. Twelve different configurations of samples were prepared by varying the porosity shapes. The mechanical behavior of samples has been provided in form of stress–strain curves at a constant and slow loading rate of 0.05 mm/min for ensuring the static condition based on Newton’s first law. Concurrent with numerical simulation, an experimental test was done on the concrete slabs containing different pores. The outcomes showed that porosity geometry plays an important role in the fracturing pattern. It was found that the porosity geometry has potent consequences on fracturing process stress and the value of the UCS for rocks. Numerical simulation shows that fracture energy decreased by increasing the dimension of the defect. Crack initiation stress was close to final stress in vertical notch configuration while the difference between the final stress and crack initiation stress has a high value for horizontal notch configuration. The sharper the hole tip, the faster the progressive failure occurred.
The main goal of this paper is to introduce an appropriate conjugate gradient class to solve unconstrained optimization problems‎. ‎The presented class enjoys the benefits of having three free parameters‎, ‎its directions are descent and it can fulfill the Dai-Liao conjugacy condition‎. ‎Global convergence property of the new class is proved under weak-Wolfe-Powell line search technique‎. ‎Numerical efficiency of the proposed class is confirmed in two sets of experiments including 210 test problems and ten disparate conjugate gradient methods‎. 2020 MSC: 90C06, 90C30, 90C26
The emergence of new diseases and the unplanned industrialization of cities have led to new diseases and the subsequent use of antibiotics. Hence the remediation of wastewater containing antibiotics and their severe pollution has raised serious concerns in recent years. Herein coral-shaped α-Fe2O3/ZnO/reduced graphene oxide (r-GO)-like carbon heterojunction in-situ were prepared from basil seed as a sustainable biomass resource and applied for the photodegradation of the oxytetracycline (OTC) as a typical antibiotic in a helical plug flow photoreactor (HPFPR) via persulfate activation under visible light irradiation. Spectroscopy and electrochemical results confirmed the tunable band structure and quick light absorption, superior charge separation and transfer, satisfactory charge carrier lifetime, and long-term stability for the prepared photocatalyst. The 98% degradation efficiency was achieved for OTC within 90 min fitted by a first-order kinetic model with the rate constant of 0.1248 min-1. The finding proves that HPFPR exhibited a higher degradation rate of OTC by 2.3 times compared to the batch reactor. The 3D computational fluid dynamics (CFD) model confirmed the outstanding performance of the HPFPR. Scavenging experiments integrated with mott Schottky and DRS results revealed that rGO intensifies the S-scheme charge carrier transfer and built-in electric field and reduces the recombination. Finally, this work has substantial potential for the in-situ synthesis of environmental-friendly and large-scale metal oxide heterojunctions in natural carbon supports as well as scale-up and gives novel insights from molecular and engineering points of view into the wastewater remediation processes and clean water production.
Mining activities are usually associated with negative outcomes. Therefore, it is crucial to identify and assess these outcomes by the mining company to achieve proper management. The present study has been defined to discover the outcomes of mining activities and their testing in one of the open pit mines of Iran. The present research has been defined into two sections, qualitative and quantitative. The corresponding data of the qualitative section were derived through analysis of the hidden contents of semi-structured interviews with experts and a review of the literature using the Maxqda 2022 software in the forms of open coding and axial coding. In the quantitative section of the study, data were collected via the standard questionnaire and analyzed using the SPSS26 and Mplus software. By coding the interviews and existing documents, 62 primary codes were extracted and classified into 5 main criteria (environmental, health, social, economic, and cultural) in the form of axial coding. The analysis results of the collected questionnaires showed that mining activities had the highest impact on the environment (86.32) and individual health (80.86), while the lower impact was on their economic situation (54.55). The findings of this study showed that there is a significant difference between men and women in terms of the environmental (p = 0.013) and economic (p = 0.01) indicators. While men believed that the mining activity had caused permanent environmental impacts on their living area, women recognized the mining activities as the cause of economic weakness in their families. Results from the present study could be effective in formulating the controlling strategies for potential negative outcomes of mining and achieving effective sustainable development.
The effects of different configurations of echelon crack on the crack propagation mechanism in the gypsum samples with different lengths and crack inclination angles under the uniaxial compressive loading condition were studied. These samples were explicitly prepared in the laboratory and tested uniaxially under compression. Bridge areas were specified by considering the 2 cm distance between the cracks. These samples contained echelon cracks with varying inclination angles of 0°, 30°, 60°, and 90°. Therefore, twelve samples with different configurations were provided and tested to investigate the effects of echelon cracks on the crack extension mechanisms of the rock-like materials under compression. These two sets of results provided an accurate and robust methodology for studying the crack extension mechanism of the rock-like materials.
In this study, the effects of SiC and TiB2 reinforcement particles on the corrosion behaviors of the surface composites of an Al5052 substrate produced with a gas tungsten arc welding (GTAW) technique were investigated. The electrochemical behaviors of the base metal (BM) and surface composites were evaluated by open-circuit potential monitoring, potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) in two solutions: 0.5 M H2SO4 and 3.5% NaCl. The results of PDP and EIS showed that by adding reinforcement particles on the surface, the corrosion resistance decreased in both environments relative to BM. Among Al5052-based surface composites, the AA5052/SiC + TiB2 composite in 3.5% NaCl solution and AA5052/TiB2 in H2SO4 solution showed the lowest corrosion resistance due to the formation of microgalvanic couples in the Al matrix. The corrosion resistance of Al5052-based surface composites in 3.5% NaCl solution was much better than that in 0.5 M H2SO4. Furthermore, scanning electron microscopy (SEM) analysis confirmed the PDP and EIS results. The SEM image of the corroded surface of AA5052/TiB2 exhibited severe pitting corrosion in both solutions relative to the other composites. In contrast, the AA5052/SiC composite showed a relatively lower corrosion rate in both 3.5% NaCl and 0.5 M H2SO4. Hardness tests provided evidence for improved mechanical properties of the composites in comparison with the BM. In particular, composites containing TiB2 showed the highest hardness, followed by AA5052/SiC + TiB2 composites.
Effects of indoor temperature (T∞) and relative humidity (RH∞) on the airborne transmission of sneeze droplets in a confined space were studied over the T∞ range of 15–30 °C and RH∞ of 22–62%. In addition, a theoretical evaporation model was used to estimate the droplet lifetime based on experimental data. The results showed that the body mass index (BMI) of the participants played an important role in the sneezing jet velocity, while the impact of the BMI and gender of participants was insignificant on the size distribution of droplets. At a critical relative humidity RH∞,crit of 46%, the sneezing jet velocity and droplet lifetime were roughly independent of T∞. At RH∞ < RH∞,crit, the sneezing jet velocity decreased by increasing T∞ from 15 to 30 °C, while its trend was reversed at RH∞ > RH∞,crit. The maximum spreading distance of aerosols increased by decreasing the RH∞ and increasing T∞, while the droplet lifetime increased by decreasing T∞ at RH∞ > RH∞,crit. The mean diameter of aerosolized droplets was less affected by T∞ than the large droplets at RH∞ < RH∞,crit, while the mean diameter and number fraction of aerosols were more influenced by RH∞ than the T∞ in the range of 46% ≤ RH∞ ≤ 62%. In summary, this study suggests suitable indoor environmental conditions by considering the transmission rate and lifetime of respiratory droplets to reduce the spread of COVID-19. Graphical abstract
In this paper, a novel robust controller is presented for fractional order model of doubly-fed induction generator (DFIG) based on variable speed wind turbine. Due to the nonlinear dynamics of the system, external disturbances, and parameter uncertainties, robust controller must be designed. To achieve a high- performance system, the generator speed and currents are controlled by a novel fractional order backstepping sliding mode controller. The input control terms are derived based on fractional calculus to reduce chattering phenomenon and increase system robustness. Also, to achieve more precise description of the system, the fractional order model of the system is investigated; in addition, total disturbance of the system is estimated by novel fractional-order sliding mode disturbance observer (FOSM-DO). The controller parameters are obtained using Ant Colony Optimization (ACO) algorithm. The most important purpose is to extract wind turbine maximum power point. Furthermore, the suggested method performance is compared with the backstepping sliding mode control (BSMC). The simulations of the proposed strategy illustrate the efficiency of the controller as well as robustness against parameter uncertainties, external disturbances and changing of the operating point.
Wind energy systems are pollution free and clean form of the renewable energy production. The dynamic model of a wind turbine system based on a doubly fed induction generator (DFIG) is exposed to external disturbances, uncertainties, and nonlinear dynamics. In this paper to ensure the system robustness against external disturbance and uncertainty in system parameters, a novel optimized fractional order robust adaptive sliding mode controller is proposed by utilizing a disturbance observer. The controller's main goal is to track the maximum power point of the wind turbine. In order to show the superiority of the proposed method, the results under normal conditions and in the presence of disturbance and uncertainty have been compared with the classical sliding mode control (SMC) and adaptive sliding mode control (ASMC). The parameters of all three controllers have been optimized by Ant Colony Optimization (ACO) algorithm. The proposed method does not need the knowledge of the upper bounds of model uncertainty and disturbance. Also by using the fractional order operators in the control signal of the proposed method, its robustness against model uncertainty and disturbance is increased and it can extract the maximum power than the other compared methods. This article is protected by copyright. All rights reserved.
Hepatitis A virus (HAV) is one of the well-known viruses that cause hepatitis all around the globe. Although this illness has decreased in developed countries due to extensive immunization, numerous developing and underdeveloped countries are struggling with this virus. HAV infection can be spread by oral-fecal contact, and there are frequent epidemics through nutrition. Improvements in socioeconomic and sanitary circumstances have caused a shift in the disease's prevalence worldwide. Younger children are usually asymptomatic, but as they become older, the infection symptoms begin to appear. Symptoms range from slight infammation and jaundice to acute liver failure in older individuals. While an acute infection may be self-limiting, unrecognized persistent infections, and the misapplication of therapeutic methods based on clinical guidelines are linked to a higher incidence of cirrhosis, hepatocellular carcinoma, and mortality. Fortunately, most patients recover within two months of infection, though 10-15% of patients will relapse within the frst six months. A virus seldom leads to persistent infection or liver damage. Te mainstay of therapy is based on supportive care. All children from 12-23 months, as well as some susceptible populations, should receive routine vaccinations, according to the Centers for Disease Control and Prevention and the American Academy of Pediatrics. Laboratory diagnosis of HAV is based on antigen detection, checking liver enzyme levels, and antibody screening. Furthermore, polymerase chain reaction (PCR) technology has identifed HAV in suspected nutrition sources; therefore, this technique is used for preventative measures and food-related laws.
Background: There is a public interest in developing bio-surfactants due to their low toxicity and high biodegradation potential. However, their biological, surface, and behavior has not been investigated to use with agrochemicals. Results: Critical micelle concentration (CMC) for synthetic surfactant dioctyl sodium sulfosuccinate (DOSS), bio-surfactant rhamnolipid (RL), and bio-surfactant surfactin (SF) were 1200, 50, and 50 mg L-1 , respectively. Based on the ability of the surfactants to reduce the surface tension of trifloxysulfuron-sodium spray solution at 0.25 to 1x CMC, they could be ranked: SF > RL > DOSS. While, at 1.5 to 4x CMC, they could be ranked: SF = RL > DOSS. Without surfactant, trifloxysulfuron-sodium at 10.04 g ha-1 controlled johnsongrass up to 50% (ED50 ). At best, SF at 1 to 4x CMC halved ED50 . Unlike DOSS, which increased ED50 (12.89 g ha-1 ) due to a phytotoxic effect, SF and RL at 4x CMC decreased ED50 (5.19 and 6.50 g ha-1 , respectively) without a phytotoxic effect. The 5-μl droplet containing SF dried faster due to the greater spread on the leaf surface than other surfactants. Although the wetted area of the leaf with the droplet containing RL was wider than that of DOSS, it dried later. This observation contradicts the previous theory. Conclusion: In terms of dosage, safety, and efficacy, the RL and SF were comparable to DOSS to tank-mix with trifloxysulfuron-sodium. It seems that RL also works as a humectant; SF likely works as a wax solubilisant. This article is protected by copyright. All rights reserved.
Energy and mass storage in various single-phase fluid flows is of particular interest, as the world currently faces energy challenges. Double-diffusive natural convection in an n-shaped storage tank is numerically studied which can be a general guideline to maintain a storage tank with higher exergy. Lattice-Boltzmann's approach in an in-house computational code is used to simulate the problem. To display the results, it is considered that the Rayleigh number lies between 10³ and 10⁵, and the Lewis number in the range of 0.1 and 10. The average Nusselt and Sherwood number, as well as entropy generation, showing the energy loss, are illustrated. It is observed that the average Nusselt and Sherwood number rises with increasing Rayleigh number and buoyancy ratio. Further, the average Sherwood number boosts by increasing the Lewis number. The most promising parameter in increasing the heat and mass transfer are found to be Rayleigh and Lewis number, respectively, with a maximum 300 percent improvement. The flow friction can be regarded as the main source of entropy generation, with a share of 90 percent. The Rayleigh number increment from 10³ to 10⁵ leads to the rise in the total entropy generation by approximately fivefold.
Dual Equal Channel Lateral Extrusion (DECLE) is performed in different passes on an annealed AA5083 aluminum alloy. The microstructural evolution of the alloy is investigated using electron backscatter diffraction images and the dislocation density is determined by X-ray line profile analysis. It is found that DECLE is effective in grain refinement, and while dislocation density is almost saturated after the fourth pass of DECLE, applying the sixth pass results in more grain size reduction of annealed sample from 59.2 μm to 3.8 μm. To assess the mechanical behavior of the DECLE-processed materials, shear punch tests (SPT) at high temperatures (300–400 °C) and various strain rates (3×10−3−3×10−1s−1) are conducted. The shear stress-normalized displacement curves obtained from SPT are utilized to obtain the material constants such as the stress exponent (n) and the activation energy (Q) in the hyperbolic-sine constitutive model. The variations of n and Q are analyzed based on the microstructural features such as grain size, HAGBs fraction, dislocation density, and second phase particles fraction. The results suggest that the Q value is competitively influenced by these parameters. Accordingly, finer grain size, higher HAGBs volume fraction, lower second phase volume fraction, and smaller dislocation density result in lower Q values.
The current study predicts West Texas Intermediate (WTI) petroleum prices using an artificial neural network (ANN) with a whale optimization algorithm (WOA). In implementing the model, five parameters, including gold price, coal price, natural gas price, Dollar-Euro exchange rate, and Dollar-Yuan exchange rate, have been used as input to the combined model. The intelligent and basic ANN algorithm results compared to finding the ANN-WOA algorithm capacity in predicting the future price of WTI oil. ANN-WOA model improved the WTI price predicting accuracy up to 22% compared to the ANN. The ANN-WOA method with a value of R2 = 0.93 compared to the ANN method with a value of R2 = 0.75 was able to reduce the model error well. According to the significant impact that the input parameters of the combination model had on the WTI oil price prediction, therefore, in studies that predict price or other variables, highly correlated variables can significantly increase the accuracy of the forecast.
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138 members
Saeid Karimi
  • Metallurgy and Materials Engineering,
Amir Momeni
  • Department of Materials Science and Engineering
Shoeib Babaee Touski
  • Department of Electrical and Computer Engineering
Mahmoud Paripour
  • Department of Mathematics
Mardom St., Fahmideh Blvd., 6516913733, Hamadān, Hamedan, Iran
Head of institution
Dr. Amir Momeni