Persian Gulf University
  • Bushehr, Bushehr, Iran
Recent publications
In this study, the assessment of metals absorption capacity by macroalgae using image analysis was investigated for the first time and compared with fish bioaccumulatio. Empirical cumulative entropy (ECE), and also empirical negative cumulative extropy (ENCEX) were used as a newly introduced (information-based) indices. The regression equation was obtained between fish tissue-seawater in muscle of Sphyraena putnamiae (ENCEX=0.2001BAF; R^2=0.96); In the case of muscle of Liza subviridis, the regression model was as (ENCEX=0.1950BAF; R^2=0.93). The regression equation was obtained between algae-sediment (ENCEXH. hamulosa=0.2695BAF; R^2=0.97). The studied indices showed a high accumulation of Hypnea hamulosa compared to the other algae (ECE=0.2601; ENCEX=0.3995). IQA method showed the same result exhibiting that the algae can be evaluated as a bio-indicator of element accumulation using image analysis. Image analysis can help us find macro algae with high absorption capacity without laboratory examinations.
For a free online copy please visit: https://www.tandfonline.com/eprint/QXK9H3R63XPXEUPUWXKD/full?target=10.1080/09571736.2022.2161206
A comprehensive study was carried out on in vitro multiplication and rooting using the medium enriched with different plant growth regulators and acclimatization of pineapple cv. ‘Smooth Cayenne’ using different soil growing substrates. The significantly highest shoot buds (Avg. 16.7) were obtained on the medium comprising 2.0 mg L−1 BA (6-Benzylaminopurine). Results showed that 1.0 mg L−1 IBA (Indole-3-butyric acid) increased the thickness and length of white adventitious roots and resulted in a significantly highest number of roots (Avg. 8) and root length (6.15 cm). Plantlets with healthy, multiple roots were transplanted in several soil combinations of river silt, bolhari (yellow sand), and peat moss. However, the significantly highest survival (100%) of plantlets in the greenhouse was obtained on the soil medium containing only peat moss. Furthermore, soil mixtures of bolhari and peat moss (1:1) and river silt alone exhibited 98.9% and 95.1% survivability of plantlets, which was also considered equally significant (at 5% probability level). The in vitro and ex vitro protocols optimized in the current study can be applied commercially for pineapple crop worldwide.
In this paper, a multiple-relaxation-time lattice Boltzmann method (MRT LBM) is used to simulate the steady fluid flow through and around a rotating porous circular cylinder in uniform flow. This study aims at investigating the effect of Darcy number (10 ⁻⁶ {less than or equal to}Da{less than or equal to}1×0 ⁻² ), velocity ratio (0{less than or equal to}VR{less than or equal to}2), and Reynolds number (Re=20 and 40) on the Magnus lift as well as on the flow pattern and pressure coefficient inside and around the rotating porous cylinder. The results reveal that besides the enveloping and detached wakes reported in the literature for rotating solid cylinders, a new type of wake called confined wake in this study is observed in this study within the rotating porous cylinders at high Darcy numbers and velocity ratios of less than one. It is seen that the Magnus lift increases almost linearly with the velocity ratio for Da{less than or equal to}10 ⁻³ , however, through curve-fitting, the rate of increase is shown to decrease with Darcy number in a non-linear manner. For Darcy numbers higher than 10 ⁻³ , the Magnus lift varies non-linearly with both velocity ratio and Darcy number in such a way that, interestingly, for Re=40 and very high Darcy numbers of 7.5×10 ⁻³ and 10 ⁻² the Magnus lift becomes negative showing a behavior called the inverse Magnus effect.
The solar flux distribution on the walls of the receivers in solar parabolic and circular collectors (PTCs and CTCs) is highly non-uniform. To prevent major problems caused by flux non-uniformity in such devices, a partially open aperture evacuated receiver (OAER) with an internal twisted insert is introduced, and its performance is compared to that of conventional evacuated receivers (CERs). A comprehensive computational fluid dynamic (CFD) model is developed for the receivers. The simulation results show that the proposed receiver has a more uniform solar flux distribution, and consequently greater energy and exergy efficiencies compared to CERs. The proposed OAER acts as a fluid turbulator, absorbs solar energy more efficiently, distributes the temperature gradient inside the absorber more uniformly, shifts the maximum temperature on the exterior surface of the CERs to the interior surface, and reduces radiative losses. The enhancement in total heat absorbed by OAER with 10 blades (OAER_10) compared to the CER_0 is 7.69%. The simulation results reveal that the average daily exergy efficiency of an OAER_10 is about 27.8% higher than a CER_0. The average daily exergy efficiency of a CER_0 is obtained to be about 7.55%, while it decreases to 7.42% for a CER_6 due to larger exergy destruction caused by air pressure drop. The introduced design offers a higher potential for efficient absorption of solar energy (proper sensible heat storage device) and provides a more useful contact area.
Turbines are efficient power generators. Because wind energy is a clean fuel source, it is widely utilized in some regions. One of the major factors affecting wind turbine performance is the angle of attack of the blade. The aerodynamics and efficiency can be improved by improvising the lift-to-drag ratio CL/CD to get the best design for wind turbine blades. There are many factors affecting the efficiency of horizontal wind turbine blades such as the angle of attack of the blade. Therefore, this study investigated the effect of the angle of attack on coefficients and forces, particularly on a blade with NACA 4412 airfoil in a horizontal axis wind turbine. The length, thickness, and chord length of the blade were 3m, 0.36m, and 0.12 m respectively. Computational Fluid Dynamics was used to develop to obtain lift and drag coefficients in a horizontal wind turbine blade. In addition, the correlation between different angles of attack, lift, and drag forces were studied and validated. The results demonstrated that the lift and drag coefficients increase as the angle of attack increases. Furthermore, the optimal angle of attack for this study was 0° because it has the highest lift-to-drag ratio, resulting in the greatest efficiency. The results demonstrated that it is possible to have a different lift and drag coefficient for the same angles of attack at a similar airfoil.
The heavy metal contaminant arsenic exist in the form of arsenite (As(III)) and arsenate (As(V)) ions. These ions are highly carcinogenic that are usually present in the ground water. To date, most of the designed polymer inclusion membrane (PIM) involved only about separation without differentiating the oxidation states. Thus, there is a research gap on separation of element with different oxidation states. Thus, this study addresses such research gap which have been not explored previously. To extract such ions from water, the present study involves fabrication of PIM by varying the compositions of the base polymer, carrier and plasticizer. Also effect of the strip solution, and transport properties were studied. High performance membrane was obtained with 50% (w/w) Aliquat 336 and 50% (w/w) Cellulose triacetate (CTA). The production of 1 m2 of PIM may cost approximately 0.08-0.16$. Also, we have combined the separation capacity of polymer inclusion membrane (PIM) with the sensitivity and elemental detection using atomic absorption spectrometry (AAS) to detect and separate As(III) and As(V). AAS is limited to detecting only elemental arsenic (As) and does not distinguish between As(III) and As(V). Further, to address such limitations in this current study we were able to separate As(V) from As(III) within 5 h. In addition, to provide sole solution a device was fabricated to extract As(V) in the field studies which displayed outstanding efficiency of 99.7 ± 0.2%. The extracted samples was tested in AAS to differentiate between oxidation states of the arsenic species and these important results are supportive in finding out the redox potential of water and for other geochemical explorations.
The present paper addresses the effect of placing an intake, as a diversion structure, in different positions and with various angles in a 180° bend to investigate the scour depth around a circular pier in an SSIIM2 numerical model. The simulation was conducted by placing the intake at the 75°, 90°, 115°, 135°, and 150° positions with 45°, 60°, and 90° angles. The results indicated that the greatest effect was associated with the installation of the intake with a 90° angle at the 135° position, which decreased the maximum scour depth by a considerable amount, about 70%, compared with the bend without an intake. However, the maximum scour depth occurred with the installation of the intake at the 150° position with an intake angle of 45° and increased by 20% compared to the bend without an intake. Furthermore, the maximum and minimum scour hole wall slopes around the pier in the case of the bend with an intake respectively increased by 6.24 times and decreased by 5.1 times compared to the bend without an intake at the upstream pier. The maximum sedimentation height around the pier decreased by about 40% in the bend with an intake compared to the one without an intake.
Polyglutamine diseases are a group of congenital neurodegenerative diseases categorized with genomic abnormalities in the expansion of CAG triplet repeats in coding regions of specific disease-related genes. Protein aggregates are the toxic hallmark for polyQ diseases and initiate neuronal death. Autophagy is a catabolic process that aids in the removal of damaged organelles or toxic protein aggregates, a process required to maintain cellular homeostasis that has the potential to fight against neurodegenerative diseases, but this pathway gets affected under diseased conditions, as there is a direct impact on autophagy-related gene expression. The increase in the accumulation of autophagy vesicles reported in neurodegenerative diseases was due to an increase in autophagy or may have been due to a decrease in autophagy flux. These reports suggested that there is a contribution of autophagy in the pathology of diseases and regulation in the process of autophagy. It was demonstrated in various disease models of polyQ diseases that autophagy upregulation by using modulators can enhance the dissolution of toxic aggregates and delay disease progression. In this review, interaction of the autophagy pathway with polyQ diseases was analyzed, and a therapeutic approach with autophagy inducing drugs was established for disease pathogenesis.
Most studies on microplastics (MPs) and organisms, regardless of the MPs type and their presence in the environment and organisms, have been performed on a laboratory scale. In this review, reports of simultaneous analysis of the abundance of MPs and organic/inorganic contaminants in aquatic organisms in the natural environment have been collected and bibliometric analysis was performed. Biological and environmental factors affecting MPs absorption by organisms were discussed. The majority of microplastics were identified as fibrous and black with a small size (<500 μm). A positive correlation was reported between microplastic numbers and organic/inorganic contaminants in the tissue of some species. The most positive linear relationship between heavy metal and MPs was reported for Heniochus acuminatus from the Gulf of Mannar. To preserve biodiversity and the risks of transferring MPs and contaminants to aquatic organisms and humans, it is necessary to control microplastic contamination.
In this research, the solid–liquid adsorption systems for MSAC (PbFe2O4 spinel-activated carbon)-phenol and pristine activated carbon-phenol were scrutinized from the thermodynamics and statistical physics (sta-phy) viewpoints. Experimental results indicated that MSAC composite outperformed pristine AC for the uptake of phenol from waste streams. By increasing the process temperature, the amount of phenol adsorbed onto both adsorbents, MSAC composite and pristine AC, decreased. Thermodynamic evaluations for MSAC demonstrated the spontaneous and exothermic characteristics of the adsorption process, while positive values of ΔG for pristine AC indicated a non-spontaneous process of phenol adsorption in all temperatures. In a mechanistic investigation, statistical physics modeling was applied to explore the responsible mechanism for phenol adsorption onto the MSAC composite and pristine AC. The single-layer model with one energy was the best model to describe the experimental data for both adsorbents. The adsorption energies of phenol onto both adsorbents were relatively smaller than 20 kJ/mol, indicating physical interactions. By increasing temperature from 298 to 358 K, the value of the absorbed amount of phenol onto the MSAC composite and pristine AC at saturation (Qsat) decreased from 158.94 and 138.91 to 115.23 and 112.34 mg/g, respectively. Mechanistic studies confirm the significant role of metallic hydroxides in MSAC to facilitate the removal of phenol through a strong interaction with phenol molecules, as compared with pristine activated carbon.
Utilizing cytochrome c (Cyt c), we studied the covalent attachment of safranin O to a protein could affect the protein properties. The effect of covalent attachment of safranin to Cyt c was explored using spectroscopic techniques, which revealed changes in the secondary and tertiary structure of the protein. Using Trp 59 fluorescence emission (λem=355 nm) and safranin fluorescence profile (λem=587 nm), we investigated the changes in the structure of the heme moiety and the binding of safranin molecules to the Cyt c protein. Far‐UV CD spectroscopy results showed that modification significantly reduced the α‐helix content. Studies showed that the modification causes the prevention of thermal aggregation of the protein at 65 °C and decreases in the peroxidase activity of the protein. Investigating of the pH effect revealed that although the Cyt c modification reduced peroxidase activity, the pH shift to pH 6.0 could increase the peroxidase activity. In this project we used a selective chemical modification of carboxyl groups in cytochrome c (Cyt c) with safranin and examined its effects on the peroxidase activity and structural properties of the protein at secondary and tertiary folding levels.
The carbon dioxide (CO2) huff-n-puff method is one of the most effective techniques for enhancing oil recovery and gas-condensate production. It involves injecting CO2 into the production well, which shuts down for some time after CO2 injection, and finally opening the well so gas and liquid can move to the surface. This chapter provides detailed explanations of several key aspects of the process, including miscibility, interfacial tension reduction, oil swelling, molecular diffusion, viscosity reduction, and vaporization of components. Based on the available studies in the literature, the relative permeability, matrix permeability, soaking time, slug size, and injection rate are also investigated as factors affecting CO2 huff-n-puff. Studies are conducted at different scales, including mathematical, numerical, experimental, pilot, and field levels. An overview of the advantages, disadvantages, and challenges of this process is provided at the end of this chapter.
The LC 50 values of cigarette butts (CBs) leachates for the P. waltoni were evaluated. • Smoked CBs leachates with tobacco (SCB) were more toxic than other CBs leachates. • Significant difference among LC 50 values of leachates at different exposure times. • SCB leachate had higher heavy metals and PAHs levels than other CBs leachates. • All CBs leachates were acutely toxic for P. waltoni. A B S T R A C T Cigarette butts (CBs) are one of the most commonly found types of litter contaminating the aquatic environment. However, the environmental risks posed by CBs need further investigation. In this study, the in-vivo toxic effects of various concentrations of CB leachates on juvenile (5.45 ± 1.36 gr and 7.08 ± 1.12 cm) fish (Periophthalmus waltoni) were evaluated. The LC 50 values of CB leachate from smoked cigarette butts with tobacco (SCB) were 3.75, 3.0, 1.94, and 1.37 CBs/L in 24, 48, 72, and 96 h exposure times, respectively. The LC 50 values for leachate of smoked CBs without tobacco (SF) were 7.58, 6.22, 4.73, and 2.9 CBs/L at 24, 48, 72, and 96 h exposure times, 2 The Persian gulf Toxicity respectively. In the case of leachate from unsmoked filters (USF), LC 50 values were 14.68, 12.44, 10.19, and 7.46 CBs/L in 24, 48, 72, and 96 h exposure time, respectively. The mean concentrations of heavy metals and polycyclic aromatic hydrocarbons in SCBs leachates were higher than in SF and USF leachates. Our findings report that even low concentrations of CBs leachates can led to lethality of P. waltoni and may pose a threat to their population density.
In the current research, we have developed a very effective, completely biocompatible, cost-effective and ecofriendly method for antifouling purposes. Melanin nanoparticles and chitosan nanoparticles were isolated from sepia ink (Sepia Pharaonis) and Penaeus merguiensis and chitosan-melanin hybrid nanoparticles complex was synthesized, under reflux circumstances to enhance the anti-biofouling properties. The result of FTIR showed that a new band between chitosan and melanin nanoparticles was in the absorption range of 1633 cm⁻¹. Moreover, TEM and FESEM analysis of chitosan-melanin hybrid nanoparticles indicated that nanoparticles are spherical. Laboratory biological assays that including antibacterial activities, antialgal activity as well as, zooplanktonic reactions in Artemia salina and barnacle Amphibalanus amphitrite to chitosan-melanin hybrid nanoparticles were evaluated. The MIC of chitosan-melanin hybrid nanoparticles was observed against E. coli (1.56 μg/mL) and S. aureus (0.871 μg/mL) and also the median inhibition concentration (IC50) value of exposed Isochrysis galbana to chitosan-melanin hybrid nanoparticles after 48 h was 0.176 mg/mL. The field immersion was evaluated in natural seawater, in different concentration (3, 2, 1 and 0.5 % wt) of chitosan-melanin hybrid nanoparticles, for 3 month. The most successful and effective results were observed for the panel with 3 wt% chitosan-melanin hybrid nanoparticles, which had lowest weight (28 g) of biofouling. According to the findings of this study, chitosan-melanin hybrid nanoparticles have ideal and good potential to antifouling properties.
The inhibition activity of sodium tri-polyphosphate (STPP) for reinforcing steel in chloride-contaminated alkaline solution with pH ranging from 12.5 to 8.5 was explored via electrochemical measurements and FESEM-EDS surface analysis. Based on the results, STPP, acting as a mixed-type corrosion inhibitor, provided the inhibition efficiencies up to 70% at all studied pHs, thus increasing the corrosion resistance of the steel rebars (at least four times) and reducing the corrosion rate significantly. The DFT and Ab-intio simulations suggested that this inhibition behavior was related to the STPP adsorption via solid chemical bonds between the oxygen heteroatoms of STPP and Fe of the metal surface.
The V-shaped permanent magnet synchronous machine (PMSM) has been successfully commercialized in hybrid-and all-electric vehicles fabricated by several famous companies. The advantages of PMSMs are a wide constant torque-speed range, high torque development capability and high power factor, and low torque ripple. In addition, the Vernier-PM (VPM) machines supersede conventional PMSM’s torque density and cogging torque. This paper presents a variable-reluctance fractional-slot V-shaped VPM (VR-FS-VVPM) machine with special rotor core surface. Hence, varying the air gap length over the direct and quadrature axes decreases the torque ripple considerably. Moreover, design of the PM-housing differs from previously introduced V-shaped VPM structures. As a result, the leakage flux in the yoke-side end-portion of the PM pieces reduces, enhancing the flux-linkage and power factor. To facilitate the design process further, an innovative equivalent magnetic network (EMN) model is established to improve performance prediction analytically. Moreover, conformal mapping is applied to create the permeance network for complex geometry air gap region. Here, a pentagonal-shape mesh-cell is used in the air gap region for capturing flux behaviour more accurately. The introduced method predicts the performance of the proposed VR-FS-VVPM machine. Finally, a typical 500 W, 12-slot/16-pole motor is designed and prototyped to validate the EMN-modelling against finite element analysis and experimental results.
Recently, Deep Convolutional Neural Networks (DCNNs) have opened their ways into various medical image processing practices such as Computer-Aided Diagnosis (CAD) systems. Despite significant developments in CAD systems based on deep models, designing an efficient model, as well as a training strategy to cope with the shortage of medical images have yet to be addressed. To address current challenges, this paper presents a model including a hybrid DCNN, which takes advantage of various feature maps of different deep models and an incremental training algorithm. Also, a weighting Test Time Augmentation strategy is presented. Besides, the proposed work develops the Mask-RCNN to not only detect mass and calcification in mammography images, but also to classify normal images. Moreover, this work aims to benefit from a radiology specialist to compare with the performance of the proposed method. Illustrating the region of interest to explain how the model makes decisions is the other aim of the study to cover existing challenges among the stateof-the-art research works. The wide range of conducted quantitative and qualitative experiments suggest that the proposed method can classify breast X-ray images of the INbreast dataset to normal, mass, and calcification.
The nonlinear vibrational characteristics and responses of sandwich beams with graphene platelets reinforced composite face sheets and porous core (GPLRC-FS-PC) subjected to a moving load is studied. Each individual layers are manufactured by uniformly distributing and randomly orienting graphene platelets (GPLs) in a metal matrix. The kinematic relations of face sheets and core layer are developed separately based on the first-order shear deformation theory (FSDT) and by employing the geometric continuity at the interface of the face sheets and core layer. The Green’s strain tensor under the von Kármán nonlinear geometric assumptions is used. The spatially discretized motion equations are derived using the Ritz method with Chebyshev polynomials multiplied by suitable boundary functions as its basis functions. The obtained nonlinear motion equations are solved by employing the Newmark and Newton–Raphson methods. After the approach is validated, parametric studies are conducted to investigate the influences of the load velocity together with the geometric parameters and material properties on the sandwich beam responses. The results indicate that the porosities softening effects depend on their distribution patterns and addition of a very small amount of GPLs, increases the overall beam stiffness significantly. It is also found that the critical load velocities may increase when increasing the porosity coefficient.
The operating rooms within the surgical unit take center stage in a hospital. The fact that, in practice, actual durations of surgery do not coincide with their allotted times yields extra costs; for example, earliness results in unutilized operating room time, and lateness incurs extra waiting for patients. Various machine learning methods are employed to predict surgery times in a hospital. The data used stems from the Shahid Chamran Trauma educational-medical hospital (Shiraz, Iran) from 2018 until 2021. The performances across the four methods, linear regression, recursive partitioning, support vector machine, and XGBoost, are compared using established accuracy and relevant healthcare operational metrics. The predicted surgery times vary per algorithm, but the differences are minor. Among the methods, linear regression shows the best performance. Linear regression, which also provides explanatory insights, outperforms the other approaches for predicting surgery times. Furthermore, the study shows that using machine learning models is a promising avenue to improve the prediction of operation time and generate more efficient and effective operating room schedules.
Institution pages aggregate content on ResearchGate related to an institution. The members listed on this page have self-identified as being affiliated with this institution. Publications listed on this page were identified by our algorithms as relating to this institution. This page was not created or approved by the institution. If you represent an institution and have questions about these pages or wish to report inaccurate content, you can contact us here.
760 members
Amirhossein Ahmadi
  • Department of Biological Science and Technology
Reza Sharafdini
  • Department of Mathematics
Vahid Morshedi
  • Department of Fisheries Science
Amir Vazirizadeh
  • Department of Marine Biology
Tahmineh Jalali
  • Department of physics
Information
Address
75169-13798 , Bushehr, Bushehr, Iran
Head of institution
Dr. A. Mosleh
Website
pgu.ac.ir