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A zeolitic imidazolate framework (ZIF-90) has been synthesized through solvothermal method. The structure was characterized by means of FT-IR spectroscopy, X-ray diffraction, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS). The synthesized ZIF-90 was applied as a support for immobilization of porcine pancreatic lipase (PPL). The immobilized enzyme (PPL@ZIF-90) exhibited immobilization yield and efficiency of 66 ± 1.8% and 89 ± 1.4%, respectively. The pH and thermal stability of PPL was improved after immobilization and the initial activity was retained at about 57% after 20 days of storage at 4 °C for PPL@ZIF-90. Moreover, about 57% of the original activity was remained following 10 cycles of application. In Michaelis-Menten kinetic studies, Km value for PPL@ZIF-90 was lower, while, the Vmax was higher than free PPL. Moreover, optimized conditions to produce fruity banana flavour upon esterification of butyric acid were investigated. The optimum esterification yield was 73.79 ± 1.31% in the presence of 245 mg PPL@ZIF-90, alcohol/acid ratio of 2.78 and 39 h reaction time. PPL@ZIF-90 showed 39% relative esterification yield after six cycles of reuse. The results suggested that PPL@ZIF-90 can be used as a potential effective biocatalyst for synthesis of isoamyl butyrate.

The thermoalkalophilic lipase from Bacillus atrophaeus (BaL) was immobilized onto amine-functionalized graphene oxide nanosheets coated with the poly (maleic anhydride-alt-1-octadecene) copolymer (GO-NH2-PMAO) and activated with glutaraldehyde as spacer arm through interfacial activation and subsequent multipoint covalent attachment. Experimental design method was applied for optimization of immobilization conditions including GO-NH2-PMAO concentration, buffer concentration, pH, sonication time, enzyme concentration, glutaraldehyde concentration, time, and temperature. The optimum specific activity of the immobilized BaL (105.95 ± 2.37 U/mg) reached at 5 mg/mL for GO-NH2-PMAO, 25 mM of buffer, pH 6.0, 60 min sonication time, 100 mM glutaraldehyde, 60 U/mL of enzyme, and 4 h of immobilization time at 25 °C, which was very close to the predicted amount (106.08 ± 1.42 U/mg). Maximum immobilization yield (81.35%) and efficiency (277.63%) were determined in optimal immobilization conditions. The obtained results clearly indicated that the immobilized BaL exhibited better stability at extreme temperature and pH than the free BaL. At temperature of 90 °C and pH 11, more than 90% of the initial activity of the immobilized BaL was retained. Furthermore, the immobilized BaL retained about 90% of its initial activity after 10 days of storage and 6 cycles of application. The esterification studies showed that maximum bioconversion of valeric acid to pentyl valerate using the free BaL (34.5%) and the immobilized BaL (96.3%) occurred in the xylene medium after 48 h of incubation at 60 °C. Therefore, the BaL immobilized on GO-NH2-PMAO was introduced as an effective biocatalyst to synthesize green apple flavour ester.

Purpose This study aims to describe the effect of magnetic field (MF) on the corrosion rate of N-80 carbon steel [N-80 carbon steel (CS)] in concentrated (12.5 Wt.%, 3.8 M) hydrochloric acid (HCl) using gravimetric weight loss (WL) measurements and potentiodynamic polarization (PDP) in various conditions at ambient temperature. Design/methodology/approach The effects of MF intensity, magnetization time and elapsed time on corrosion rate (CR) reduction (η) were studied. Findings The experimental results show that pre-magnetization of HCl sharply decreases the corrosion rate of N-80 carbon steel (CS) in acid. The maximum η was found to be 94%. The surface of CS was analyzed with scanning electron microscope in normal and magnetized acid. Originality/value To the best of the authors’ knowledge, no studies have delved into the effects of magnetization on the corrosion rate of CS in concentrated HCl solutions. All of the previous research studies deal with an external MF that is applied on the reaction cell, but the magnetization of fluid before coming in contact with CS is investigated for the first time. In the present work, the influence of MF on the corrosion rate of CS in HCl is illustrated using gravimetric WL and PDP methods. The effects of MF intensity as well as period of magnetization and elapsed time were verified in more than 35 tests.

Background In the last five years, a new generation of advanced numerical methods was developed to reduce computational costs and improve the prediction process. The combination of Artificial Intelligence and traditional computational methods is the best sample of this generation. Employing this method can expand the horizon of numerical modeling. This method is also suitable for complex processes such as natural convection and oscillating heat transfer. This case study tries to peruse the effects of variable boundary conditions such as magnetic field, angle, and nanofluids volume fraction on the heat transfer. Also, the impact of oscillation has been studied. Methods To accomplish these aims, numerical modeling of natural convection based on Boussinesq approximation was used. Techniques from machine learning were employed to develop a predictive tool that utilizes the data generated by computational analysis of the problem. The Ra and Ha were considered in the ranges of 103 Findings The result showed that Nu increased in initial steps and then decreased at a constant Ha by increasing the rotation angle. It appeared that the amplitude of oscillation has a pronounced effect on the heat transfer rate. The results show that the Ha could affect streamlines of fluid. By increasing Ha=0 to Ha=52, the maximum velocity point in the close enclosure moved 14% closer to the hot side.

Nonconformities are the major sources of waste in manufacturing process. Nonconformities cannot be fully eliminated but their occurrence rate can be predicted. This paper proposes a hybrid approach...

Experimental and numerical investigations were performed to evaluate the effects of the exit nozzle configuration of a fluidic oscillator on the flowfield and impingement heat transfer performance ...

The present study conducts a comparative experimental study on the dynamic thermal response and performance of a conventional SAH and SAH equipped with PCM using paraffin packs. Various scenarios were investigated to assess the impacts of PCM usage, PCM melting point, and arrangements of PCM slabs with different melting points on the dynamic thermal response of SAHs. To this aim, two V-type corrugated serpentine SAH prototypes, including conventional and PCM-integrated ones, were simultaneously constructed and tested under field conditions. Two types of paraffin wax with different melting temperatures, 40 °C and 50 °C, with four PCMs arrangements, were installed on a SAH. The experimental runs were carried out in Kerman, Iran, for two air mass flow rates of 0.006 kg/s and 0.01 kg/s. The acquired results illustrated that utilizing PCM improves daily thermal performance from 53.1% to 62.6%. Using PCMs with higher melting point temperature results in increasing the outlet temperature of SAHs almost 5 °C, as well as the daily performance of SAHs by approximately 3%. Furthermore, experimental runs prove that an arrangement with equally distributed PCM types with different melting points has the optimal daily thermal performance and shows approximately 5% improvement in thermal performance.

Antibacterial photodynamic therapy (aPDT) has drawn increasing attention as a noninvasive approach to remove bacterial contaminants such as E. faecalis from the tooth surface. In this study, curcumin (CUR) was loaded into ZSM-5 zeolite and the prepared photosensitizers (CUR@ZSM) were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet–visible spectroscopy (UV–Vis). The loading efficiency, and release behavior of CUR were studied in CUR@ZSM. The antimicrobial and anti-biofilm potential of the photosensitizer were evaluated against E. faecalis via colony forming unit and crystal violet assays, respectively. No significant changes were observed in the size, morphology and crystallinity of the zeolite after CUR loading. CUR@ZSM showed a significant photodynamic inactivation effect through complete bacterial elimination and reduced the biofilm formation ability of E. faecalis up to about 80%. The results revealed that CUR@ZSM could be considered as a new potential photosensitizer for further study against endodontic infections.

In this study, the manufacturing and testing of an infrared dryer equipped with a PV/T solar collector were investigated. The total energy for the drying process is provided by solar energy. This study sought to compare the experimental results of glazed and unglazed modes and observe the effect of volume flow rate variations on the drying process of the products to determine the dryer’s energy and exergy efficiency and analyze the drying kinetic of potato slices. The amount of inlet airflow to the PV/T was controlled during the experiment. The power of the fan is supplied directly from two photovoltaic panels and the surplus amount of electrical energy is assigned to an infrared radiation source to enhance the process. Despite the low energy consumption of the current system, the products’ drying time was significantly reduced compared to similar systems. As a result, in glazed experiments, the drying time is prolonged in a range of 12–25% for 3 mm thicknesses and between 5 and 25% for 7 mm thicknesses compared to unglazed experiments. The maximum system energy efficiency and system exergy efficiency were 9% and 0.5%, respectively, calculated for 7 mm slices in unglazed tests.

In this study, polycaprolactone/gelatin (PCL/GEL) electrospun nanofibers containing biogenic selenium nanoparticles (Se NPs) and Se NPs/vitamin E (VE) with average diameters of 397.8 nm and 279.5 nm, respectively (as determined by SEM inspection) were prepared and their effect on wound healing was evaluated using in-vivo studies. The energy dispersive X-ray (EDX) mapping, TEM micrograph, and FTIR spectra of the prepared nanofibers strongly demonstrated well entrapment of Se NPs and VE into scaffolds. An amount of 57% Se NPs and 43% VE were gradually released from PCL/GEL/Se NPs/VE scaffold after 4 days immersion in PBS solution (pH 7.4). The both PCL/GEL/Se NPs and PCL/GEL/Se NPs/VE scaffolds supported 3T3 cell proliferation and attachment as confirmed by MTT assay and SEM imaging. Complete re-epithelialization, low level of edema and inflammatory cells in coordination with high level of oriented collagens demonstrated the wound healing activity of PCL/GEL/Se NPs/VE. Besides, significant antioxidant efficacy of PCL/GEL/Se NPs and PCL/GEL/Se NPs/VE scaffolds was demonstrated according to GSH and MDA assays. To sum up, the prepared PCL/GEL/Se NPs/VE scaffold in the present study represented suitable healing effect on animal model which candidate it for further studies.

The present article experimentally explored heat transfer through a horizontal metal foam tube with a constant wall heat flux during the subcooled flow boiling of water, Al2O3/H2O, and CuO/H2O nanofluids. To investigate the effect of using metallic foam on the subcooled flow boiling heat transfer, the results have been compared with a simple tube. Besides, The impacts of significant parameters, including subcooled inlet temperature (25–60 °C), mass flux (150–310 kg m−2 s−1), wall heat flux (100–230 kW m−2), particle type (CuO and Al2O3), and nanofluids concentration (0.5% wt., 1% wt.) were investigated on the transfer of boiling heat while measuring pressure loss and rate of heat transfer. The results show that the use of metal foam increases the heat transfer rate by 3.5–5.8 times compared to the simple tube. Comparing the subcooled flow boiling heat transfer of water and nanofluids in both metal foam and simple tubes, it was found that water has superiority over the nanofluids. Besides, the value of the thermal performance index defined as a ratio of the heat transfer enhancement to the pressure loss degradation is more than one for water and the nanofluids.

This study was performed to synthesize and characterize NaY and ZSM-5 zeolites and their hierarchical forms (HR-Y and HR-Z) through dealumination and soft templating procedure. The Brunauer-Emmett-Teller (BET) analysis showed significant increase in the average pore diameter (DP) size for HR-Y (2.43 nm) and HR-Z (5.07 nm) compared to those of the parent types (NaY and ZSM-5: 1.85 and 2.01 nm, respectively). The mesoporous pore volumes (Vmeso) exhibited notable enhancement for HR-Y (114%) and HR-Z (566%) compared to their parent forms. Laccase (Lac) was subsequently immobilized on NaY and ZSM-5 zeolites, and their hierarchical forms by immobilization efficiency of 74.4 ± 1.4%, 71.6 ± 1.0%, 98±2.9%, and 94±1.8% for Lac@NaY, Lac@ZSM-5, Lac@HR-Y, and Lac@HR-Z, respectively. Thermal and pH stability of the immobilized laccases were enhanced compared with the free enzyme. The relative activity for the immobilized laccases was kept over 50% of its original activity after about 3 weeks of storage at 4 °C. Moreover, reusability of Lac@HR-Z and Lac@HR-Y was considerably higher (68% and 92%, respectively) than those of Lac@ZSM-5 and Lac@NaY (6% and 5.6%, respectively) after 10 cycles of reuse. Lac@HR-Z and Lac@HR-Y exhibited higher efficiency (80.5% and 89.3%, respectively) in phenol bio-removal compared with those of ZSM-5 (67.5%) and NaY (76.5%). Besides, 90.4 ± 1.3% of phenol was practically removed under optimal conditions including 12 U/mg of Lac@HR-Y, 2.6 mM of phenol, and 70 min of the reaction time. Lac@HR-Y also exhibited 56% efficiency after 10 cycles of phenol removal. Furthermore, three phenolic compounds were detected by GC-mass analysis due to phenol bio-removal in the optimal conditions after removing the dark brown precipitate of polymerized metabolites. Therefore, Lac@HR-Y could be suggested for the elimination of phenol-containing pollutants that merits further investigations.

Lack of potable water around the world has become a global problem. Solar stills are one of the main technologies for freshwater production. The performance of these stills can be enhanced by applying nanoparticles in the water. In this research, γ-Al2O3 nanoparticles have been used as an effective approach for pure water production in a single slope basin solar still in the presence of mixer. The nanoparticles were synthesized and verified using FTIR, XRD and SEM analyses. The effects of the amount of γ-Al2O3 nanoparticles, initial water depth, the solar energy intensity and the presence of mixer on the distillate yield, water depth and the temperatures of glass, bottom and brine have been investigated. The results showed that 0.3 mass% of γ-Al2O3 increased the distillate yield by about 60.03%. Due to more water evaporation in experiments with γ-Al2O3, the water depth reduction is more than the experiments without addition of nanoparticles. The increase in glass, bottom and brine temperatures were more significant in tests with nanoparticles. Presence of mixer in the basin uniformly dispersed the nanoparticles throughout the still and increased the evaporation rate and finally the distillate yield. In general, applying γ-Al2O3 nanoparticles enhanced the performance of still due to improving the thermal characteristics of saline water.

Catalytic upgrading of 4-methylanisole as a representative of lignin-derived pyrolysis bio-oil was investigated over Pt/γ-Al2O3 catalyst. The catalytic upgrading process was conducted at different operating condition to determine the detailed reactions network. Additionally, artificial neural network and design of experiment were applied by feeding the reaction temperature, operating pressure and space velocity to predict 4-methylanisole conversion, main products selectivity, reactions rate and reactions network. The main products of 4-methylanisole upgrading were toluene, phenol derivatives, cyclohexanone, 4-methylcyclohexanone, and 2-tert-butyl-4-methylphenol. The major classes of reactions during the upgrading process were hydrogenolysis, hydrodeoxygenation, alkylation, and hydrogenation. For optimization of experimental data obtained at suggested conditions by design of experiment, the response surface methodology was applied. Artificial neural network model was used to investigate the kinetics behavior of the system due to the complex nature of system. A combination of the response surface methodology, artificial neural network, and design of experiment has revealed its ability to solve a quadratic polynomial model. The coefficients of determination were close to 1, and the mean square error of the artificial neural network model was close to 0 which showed the high accuracy of model predictions. It was inferred that during the upgrading process of 4-methylanisole, increasing temperature and pressure and setting space velocity at the minimum value are the reasons to come close to the optimum reaction rate. The comparison of experimental results with simulated data from the artificial neural network and the response surface methodology models illustrated that the developed model can create an applicable situation for practical design of large-scale production of valuable fuels from renewable resources.

In the present paper, the hydrodynamic performance of stepped planing craft is investigated by computational fluid dynamics (CFD) analysis. For this purpose, the hydrodynamic resistances of without step, one-step, and two-step hulls of Cougar planing craft are evaluated under different distances of the second step and LCG from aft, weight loadings, and Froude numbers (Fr). Our CFD results are appropriately validated against our conducted experimental test in National Iranians Marine Laboratory (NIMALA), Tehran, Iran. Then, the hydrodynamic resistance of intended planing crafts under various geometrical and physical conditions is predicted using artificial neural networks (ANNs). CFD analysis shows two different trends in the growth rate of resistance to weight ratio. So that, using steps for planing craft increases the resistance to weight ratio at lower Fr and decreases it at higher Fr. Additionally, by the increase of the distance between two steps, the resistance to weight ratio is decreased and the porpoising phenomenon is delayed. Furthermore, we obtained the maximum mean square error of ANNs output in the prediction of resistance to weight ratio equal to 0.0027. Finally, the predictive equation is suggested for the resistance to weight ratio of stepped planing craft according to weights and bias of designed ANNs.

Wind as an environmental condition plays a crucial role in the heat dynamics of pavement solar collectors (PSCs) and causes convective heat loss to the ambient. The major emphasis of the present study is to evaluate the effects of wind velocity on the thermal efficiency of glazed and unglazed PSCs. Since the wind velocity is a chaotic and random function, it is challenging to evaluate wind velocity effects experimentally. Therefore, a PSC prototype was constructed, and a computational fluid dynamic (CFD) model was developed and validated by the acquired experimental results. Then, the CFD model was employed to evaluate the wind velocity effects on the dynamics of PSCs. Three scenarios considering wind velocities in the ranges from 0 m/s to 20 m/s were assumed, and the dynamics of the constructed glazed and unglazed PSCs were monitored. The obtained results illustrated that by increasing wind velocity from 0 m/s to 20 m/s, the maximum outlet water temperature decreases by near 25% and 10% for the unglazed PSC and glazed one, respectively. The validated numerical model shows that increasing wind velocity caused the thermal performance to be reduced by around 68% and 25% for the unglazed and glazed PSCs, respectively.

This work aimed to study the influence of contamination profiles and humidity on flashover electrical characteristics of polluted insulators. Firstly, the flashover tests on cap and pin glass insulators under four pollution levels represented by salinity were conducted. Eight artificial contamination profiles based on the solid layer method have been modeled for the selected insulators. The numerical analysis has been used to determine the insulator electrical characteristics such as potential, electric field, and power dissipation under proposed contamination profiles using finite element methods (FEM). Next, the power dissipation has been simulated with consideration of thermal stress propagation in locations with high power. Finally, flashover voltage gradient tests have been conducted under various humidity and contamination profiles. The values of the flashover voltage gradient due to pollution were determined as the percentage of the value of the flashover voltage gradient in the clean condition which was identified as the reference point. The numerical model indicated that the initiation of arc generally occurs at area in which the electric field and power dissipation is maximum. It was also observed from experimental results that the flashover voltage gradient under different contamination profiles has different values depends on the location and dimension of the pollution region.

High molar mass materials (nano-silica slurry [NSS] and aggregate of steel furnace slag [ASFS]) can improve concrete shielding properties. However, only a few studies have been reported in this regard. Hence, this paper aims to determine the effect of NSS and ASFS on the properties of the resulting steel slag heavyweight concrete (SSHWC). The use of NSS in this study is a novel contribution. Furthermore, the maximum percentage of NSS to be introduced into the concrete for maximum effect was also optimized. This study also implemented an investigation program with six concrete mixtures prepared using ASFS as the primary by-product aggregate. The engineering, X-ray, and γ-ray attenuation characteristics of the SSHWC were evaluated. The results showed that the addition of NSS in SSHWC at the optimal content of 3% by weight of cement improved the X-ray shielding by 6.4%. Besides, all the concrete’s engineering and γ-rays’ properties were enhanced correspondingly.

A novel xylanase gene xynBCA, encoding a polypeptide of 439 residues (XynBCA), was cloned from Caldicoprobacter algeriensis genome and recombinantly expressed in Escherichia coli BL21(DE3). The amino acid sequence analysis showed that XynBCA belongs to the glycoside hydrolase family 10. The purified recombinant enzyme has a monomeric structure of 52 kDa. It is active and stable in a wide range of pH from 3 to 10 with a maximum activity at 6.5. Interestingly, XynBCA was highly thermoactive with an optimum temperature of 80 °C, thermostable with a half-life of 20 min at 80 °C. The specific activity was 117 U mg−1, while the Km and Vmax were 1.247 mg ml−1, and 114.7 μmol min−1 mg−1, respectively. The investigation of XynBCA in kraft pulp biobleaching experiments showed effectiveness in releasing reducing sugars and chromophores, with best achievements at 100 U g−1 of pulp and 1 h of incubation. The comparative molecular modeling studies with the less thermostable Xylanase B from Clostridium stercorarium, revealed extra charged residues at the surface of XynBCA potentially participating in the formation of intermolecular hydrogen bonds with solvent molecules or generating salt bridges, therefore contributing to the higher thermal stability.

The chalcopyrite semiconductor CuInSe2 and its constitutes Ga and/or S [Cu (InGa)Se2 or Cu (InGa)(Se,S)2], commonly referred as CIGS have been leading thinfilms for incorporation in high-efficiency photovoltaics. In conventional ZnO-N/i-ZnO/CdS/CIGS solar cells, the traditional CdS buffer is nearly optimum for the commonly used 1.15 eV (CIGS) but less optimal for higher Ga. To overcome this limitation, Cd1-yZnyS is proposed as an alternative buffer layer to replace the standard CdS in CIGS thinfilm solar cells containing an ordered vacancy compound (OVC) layer. Next, the dependence of solar cells performance on the change of Ga and Zn concentrations in absorber and buffer layers, respectively, was investigated using the AMPS-1D software. The results are potential improvement in CIGS efficiency that was obtained with replacement of CdS buffer material by its alternative in one hand, another hand by formation of OVC layer. Lastly, the optimum values of Ga and Zn concentrations were found at 0.7 and 0.6, respectively, leading to a high conversion efficiency of around 23.71%.

Perovskite solar cells (PSCs) have been developed as a promising photovoltaic technology because of their excellent photovoltaic performance. However, interfacial recombination and charge carrier transport losses at the surface greatly limit the performance and stability of PSCs. In this work, the fabrication of high-quality PSCs based on methylammonium lead iodide with excellent ambient stability is reported. An anionic surfactant, sodium dodecylbenzene sulfonate (SDBS), is introduced to simultaneously passivate the defect states and stabilize the cubic phase of the perovskite film. The SDBS located at grain boundaries and the surface of the active layer can effectively passivate under-coordinated lead ions and protect the perovskite components from water-induced degradation. As a result, a champion power conversion efficiency (PCE) of 19.42% is achieved with an open-circuit voltage (VOC) of 1.12 V, a short-circuit current (JSC) of 23.23 mA cm-2, and a fill factor (FF) of 74% in combination with superior moisture stability. The SDBS-passivated devices retain 80% of their initial average PCE after 2112 h of storage under ambient conditions.

Lack of investment in the electricity sector has created a huge bottleneck in the continuous flow of energy in the market, and this will create many problems for the sustainable growth and development of modern society. The main reason for this lack of investment is the investment risk in the electricity sector. One way to reduce portfolio risk is to diversify it. This study applies the concept of portfolio optimization to demonstrate the potential for greater use of renewable energy, which reduces the risk of investing in the electricity sector. Besides, it shows that investing in renewable energies can offset the risk associated with the total input costs. These costs stem from the volatility of associated prices, including fossil fuel, capital costs, maintenance, operation and environmental costs. This case study shows that Iran can theoretically supply ~33% of its electricity demand from renewable energy sources compared to its current 15% share. This case study confirms this finding and predicts that Iran, while reducing the risk of investing in electricity supply, can achieve a renewable energy supply of ~9% with an average increase in supply costs. Sensitivity analysis further shows that with a 10% change in input cost factors, the percentage of renewable energy supply is only partially affected, but basket costs change according to the scenario of 5–32%. Finally, suggestions are made that minimize risk rather than cost, which will bring about an increase in renewable energy supply.

Known as a main neural MAP (microtubule associated protein), tau protein contributes to stabilizing microtubules involved in cellular transmission. Tau dysfunction is mainly associated with neurodegenerative diseases, particularly Alzheimer's disease (AD). In these patients, all the six tau isoforms, which are in hyperphosphorylated form, are first aggregated and then polymerized into neurofibrillary tangles inside the brain. Tau protein detected in cerebrospinal fluid (CSF) is significantly correlated with AD and is well recognized as a hallmark of the disease. Served for detection of analytes of interest, biosensor device comprises a physical transducer and a keen biological recognition component. Qualitative and quantitative evaluations may be performed through analyzation of the data, which is gathered by measurable signals converted from biological reaction. Antibodies, receptors, microorganisms, nucleic acids, enzymes, cells and tissues, as well as some biomimetic structures, normally constitute the biosensor biological recognition part. Production of nanobiosensor, which was made possible through several accomplishments in nano- and fabrication technology, opens up new biotechnological horizons in diagnosis of multiple diseases. In recent years, many researches have been focused on developing novel and effective tau protein biosensors for rapid and accurate detection of AD. In this review, tau protein function and correlation with AD as well as the eminent research on developing nanobiosensor based on optical, electrochemical and piezoelectric approaches will be highlighted.

The importance of exchangers in the competitive ambiance of different industries has been proven. One of the most widely used exchangers in the industry, especially in the oil and gas industry, is ...

We introduce and study forcing number for fuzzy graphs. Also, we compute zero forcing numbers for some classes of graphs and extend this concept to fuzzy graphs. In this regard we obtain upper bounds for zero forcing of some classes of fuzzy graphs. We will proceed to obtain a new algorithm to computing zero forcing set and finding a formula for zero forcing number, and by some examples we illustrate these notions. Finally, we introduce some applications of fuzzy zero forcing in medical treatments.

Poly(allylamine) graft polymers have been shown to hold potential as drug delivery vehicles and complexation agents for biological molecules such as insulin. The nanoparticles formed upon aggregation or complexation allow for enhanced cellular trafficking resulting in enhanced efficacy. Multiple reports have shown the ease of synthesis and reliability of these graft polymers, however, little investigation into the effect of the molecular weight of the homopolymer poly(allylamine) has been carried out. In this work we synthesized a range of oxadiazole grafted poly(allylamine) derivatives of varied molecular weight (15, 17.5, 120 & 900 kDa) set at a 5% polymer:oxadiazole mole grafting. The effect of molecular weight on the size, critical aggregation concentration and drug loading/release was evaluated in model drugs before loading the optimal formulation with doxorubicin and carrying out a preliminary cytotoxicity study. In line with other cationic polymers, the larger poly(allylamine) amphiphilic derivatives resulted in greater drug loading, however, the particle size increased whilst drug loading dramatically decreased, which for cancer nanomedicine could be a barrier for pharmaceutical use.

In the current article, the effect of nanofluid blast on the forced convection heat transfer in the intra-channel turbulent flow with a sudden expansion is investigated. The different cases of Newt...

The study focused on the performance enhancement of a PDMS membrane using PMHS as the curing agent, and by incorporation of silica nanoparticles with four different silica contents of 2.5, 5, 7.5 and 10 wt%. The membranes were synthesized and applied as the separation elements to improve the separation of DMSO from their aqueous solutions. The properties of the membranes were studied by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), field emission scanning electronic microscopy and thermal gravimetric analysis (TGA). ATR-FTIR results indicated the integration of silica nanoparticles into the nanocomposite membranes and also confirmed the cross-linking reaction between the PMHS and the PDMS. The TGA curve of hybrid membranes displayed that the proper incorporation of SiO2 nanoparticles could clearly improve the thermal stability of the unfilled membrane. Moreover, swelling of prepared membranes was attained for different feed solutions. Results showed that the separation factor and flux of the PDMS/PMHS membrane were enhanced by the incorporation of hydrophobic silica particles into the composite. The maximum separation factor of 830.33 was achieved for the feed mixture with an initial DMSO concentration of 25 vol%, using the membrane with 5 wt% silica content.

In the present work, the lipopeptide biosurfactant (LPB) produced by Acinetobacter junii B6 was applied for the production of gold nanoparticles (Au NPs). Several methods, including transmission electron microscopy (TEM), UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and scanning electron microscopy (SEM), were used to determine the properties of the synthesized Au NPs. TEM and SEM images of Au NPs showed spherical and mostly hexagon-shaped and well-dispersed nanoparticles in the range of 10–17 nm. Cytotoxic activity of the Au NPs (assisted by WST-1 assay) revealed IC50 (μg/ml) of 89.08 ± 0.4, 646.12 ± 0.5, 3.37 ± 0.1, and 770 ± 0.15 against cell lines of U87, A549, MCF7, and 3T3, respectively. However, the anti-proliferative activities of biogenic Au NPs were significantly lower (IC50 of 770 ± 0.15 μg/mL) than HAuCl4 (IC50 of 0.26 ± 0.03 μg/mL) against 3T3 normal cell. The attained results of the antibacterial effect of the produced Au NPs and Au3+ ions revealed that Au3+ ions had a higher inhibitory effect than Au NPs against 3 Gram-positive and 4 Gram-negative bacterial strains. In the present study, we introduced a green approach for the synthesis of Au NPs using non-toxic and biodegradable LPBs in the absence of any chemical reducing agent.

Background: Arcus Senilis (AS) appears as a white, grey or blue ring or arc in front of the periphery of the iris, and is a symptom of abnormally high cholesterol in patients under 50 years old. Objective: This work proposes a deep learning approach to automatic recognition of AS in eye images.Material and Methods: In this analytical study, a dataset of 191 eye images (130 normal, 61 with AS) was employed where ¾ of the data were used for training the proposed model and ¼ of the data were used for test, using a 4-fold cross-validation. Due to the limited amount of training data, transfer learning was conducted with AlexNet as the pretrained network. Results: The proposed model achieved an accuracy of 100% in classifying the eye images into normal and AS categories. Conclusion: The excellent performance of the proposed model despite limited training set, demonstrate the efficacy of deep transfer learning in AS recognition in eye images. The proposed approach is preferred to previous methods for AS recognition, as it eliminates cumbersome segmentation and feature engineering processes.

Temporary keyword search on confidential data in a cloud environment is the main focus of this research. The cloud providers are not fully trusted. So, it is necessary to outsource data in the encrypted form. In the attribute-based keyword search (ABKS) schemes, the authorized users can generate some search tokens and send them to the cloud for running the search operation. These search tokens can be used to extract all the ciphertexts which are produced at any time and contain the corresponding keyword. Since this may lead to some information leakage, it is more secure to propose a scheme in which the search tokens can only extract the ciphertexts generated in a specified time interval. To this end, in this paper, we introduce a new cryptographic primitive called key-policy attribute-based temporary keyword search (KP-ABTKS) which provide this property. To evaluate the security of our scheme, we formally prove that our proposed scheme achieves the keyword secrecy property and is secure against selectively chosen keyword attack (SCKA) both in the random oracle model and under the hardness of Decisional Bilinear Diffie-Hellman (DBDH) assumption. Furthermore, we show that the complexity of the encryption algorithm is linear with respect to the number of the involved attributes. Performance evaluation shows our scheme's practicality.

Wireless body area networks (WBANs) are usually used to collect and monitor health-related information for both critical and non-critical patients. However, the traditional WBAN communication framework is unable to guarantee the successful delivery of critical information due to a lack of administrative control and priority support for emergency data. To overcome these issues, this paper proposes a novel software-defined networking (SDN)-based WBAN (SDWBAN) framework for application-specific traffic management. An application classification algorithm and a packet flow mechanism are developed by incorporating SDN principles with WBAN to effectively manage complex and critical traffic in the network. Furthermore, a Sector-Based Distance (SBD) protocol is designed and utilized to facilitate the SDWBAN communication framework. Finally, the proposed SDWBAN framework is evaluated through the CASTALIA simulator in terms of Packet Delivery Ratio (PDR) and latency. The experimental outcomes show that the proposed system achieves high throughput and low latency for emergency traffic in SDWBANs.

Structural, electronic, elastic, and transport properties of FeVX (X = As, P) half-Heusler (HH) compounds have been calculated using density functional theory (DFT). The generalized gradient approximation developed by Perdew–Burke–Ernzerhof (GGA-PBE) is utilized for the calculation of the structural properties and the mechanical parameters of FeVX (X = As, P), indicating that the studied compounds are mechanically stable. The Tran and Blaha-modified Becke–Johnson potential (TB-mBJ) is utilized to improve the investigation of the electronic structure and also indicates that the FeVX (X = As, P) compounds are narrow-gap semiconductors. Calculations of transport efficiency are performed using the semiclassical Boltzmann theory. The figure of merit ZT is near unity at room temperature, indicating that both compounds are good candidates for use in transport devices.

This paper is aimed at investigating optimised mirror layout effects of Linear Fresnel Concentrators (LFC) by evaluating the annual energy and exergy efficiencies. Subsequently, a north–south centr...

In this paper, the thermal characteristics of an evacuated tube solar collector for different volumetric flow rates of the fluid (10, 30 and 50 l/h) was experimentally improved by using copper oxide/distilled water (Cu2O/DW) nanofluid, and parabolic concentrator. Moreover, the effect of different volume fractions of the utilized nanofluid on the fluid properties, such as convective heat transfer coefficient, Nusselt number, and the useful gain of the collector was experimented. Finally, three artificial intelligence (AI) techniques namely, multi-variate adaptive regression spline (MARS), model tree (MT) and gene-expression programming (GEP) have been employed to predict the energy efficiency ( η І ) and inlet-outlet water temperature difference (ΔT). The input variables were volume of the storage tank (V), volume fraction of the nanofluid (VF), and mass flow rate of the fluid ( M ˙ ). The proposed AI methods presented robust formulations for prediction of η І and ΔT with an acceptable level of precision. The statistical results of AI models demonstrated that the MARS method can make a more accurate prediction of the collector performance than GEP and MT. It was also concluded that increase in both flow rate, and concentration of the nanofluid, lead to an increase in the thermal performance of the solar collector.

Exposure to solar irradiation for an extended period during a day causes asphalt pavements can reach to a considerable temperature. Consequently, they can be converted into an affordable solar collector by harvesting thermal energy. In recent years much effort and time have been devoted to improving the thermal performance of solar collectors. To this aim, the glazing strategy is a promising technique. The glass covers results in the reduction of heat loss and protecting the asphalt surface (absorber surface) from the outside environment. Little attention has been given to the glazing strategy in improving the performance of ASCs. The chief aim of the current investigation is a comparative assessment of the performance and heat dynamics of unglazed asphalt solar collectors with glazed asphalt solar collectors under field conditions. The evaluation was carried out using an experimental test-setup composed of an asphalt solar collector with a surface area of 1.2 m2 and a pipe network length of 12 m. Various sensors were utilized to monitor and measure the key parameters such as ambient conditions and working fluid temperature during the experimental runs. The experimental results prove that the glazing strategy is an effective method to improve the performance of ASCs. The constructed glazed ASC increases hot water temperature, meanly around 5 °C, and pavement temperature, meanly around 20 °C, while represents an improvement in the performance, near 10%, compared with the unglazed one.

In this study, thin layer drying experiments of direct and indirect natural convection solar drying of wastewater sewage sludge in Algeria were conducted. The purpose of these was to analyze the effect of two methods of drying on different parameters, namely: drying rate, efficient diffusion of moisture, and thermodynamic parameters. Three new universal drying kinetic models were proposed and compared with four other models existing in the literature to model the drying process. The effective diffusivity of moisture of sludge (Deff) changed from 1.91 10−8 to 9.12 10−8 m2 s−1. It was obtained by using Fick's second law, based on the resolution by Laplace's transformation method and the Fourier series. Thermodynamic parameters, to know, activation energy, free energy change, enthalpy and entropy change, were also determined using a new methodology build on the evolution of effective diffusion coefficient in terms of temperature by adopting the Eyring equation.

In this study, acid fracturing treatments were simulated for a tight limestone reservoir within a shale formation using FRACPRO software. The purpose was to investigate the optimum acid fracturing design that leads to a higher fracture etched length and width, and higher fracture conductivity. Moreover, the impact of the rock-acid contact time and whether to consider a post-flush or fluids flowback, on the acid fracturing outcomes were also investigated. A simple geological model was constructed which consists of different lithological layers. Different acid fracturing design scenarios were considered starting from a single stage of acid injection to multi-stage treatment. In multi-stage acid treatment, alternate acid-slickwater injection was considered. Plain HCl acids with different concentrations and other acids that are already included in FRACPRO database were used. The results showed that the acid loss during post-flush is among the main problems of the acid fracturing in tight carbonate shale reservoir. For the single stage of acid injection, it is recommended to flow back the acid after well shut-in instead of considering a post-flush stage. The multi-stage alternate acid slickwater injection reduces or even eliminated the acid loss. However, it is recommended to inject a slickwater before well shut-in to reduce the rock-acid contact time, thus reducing the formation damage. The results also showed that the created fracture etched width decreases and the fracture etched length increases as the fracturing stages increase. In this study, because of the low carbonate layer permeability and compressive strength, a two-stage alternate 28% HCl and slickwater injection with a post-flush stage is recommended. Keywords: Acid fracturing, Tight carbonate, Acid loss, Low compressive strength, Single stage acid fracturing, Multi-stage acid fracturing

The aim of the present study was to investigate the effect of color attributes of appearance on the corresponding geometric attributes of appearance of non-effect coatings. Three scales, namely gloss, distinctness of image, and orange peel for three achromatic (black, gray, and white) and four chromatic (red, green, blue, and yellow) basecoats, each at varying levels, were prepared. The gloss and the distinctness of image scales had a sample with a maximum degree of gloss and distinctness of image, respectively, and the orange peel scale had a sample with a minimum degree of orange peel, which was considered to be the standard sample. The visual differences between the standard sample and those remaining in each scale were assessed by a panel of 28 observers using a prepared one-dimensional lightness scale based on the CIELAB and CIEDE2000 color difference equations. The correlations between visual and instrumental measurements of scales were checked, and instrumental performance with respect to visually assessed equivalent differences in gloss, distinctness of image, and orange peel were determined, giving STRESS (standardized residual sum of squares) values = 24.3, 11.6, and 9.7, respectively, in terms of CIELAB. ANOVA together with simple, lasso, and ridge regressions were applied to test the effect of color on the geometric attributes of appearance. The results illustrate that color attributes of appearance have no adverse significant effect on the main geometric attributes of appearance for non-effect coatings.

In this work, 14 reinforced concrete solid and hollow beams were tested under four-point bending test to evaluate the flexural behavior of hollow concrete beams. The experimental program focused on two main variables which are the size reduction percentage and the inclusion of steel fiber. In addition, the longitudinal reinforcement ratio and the presence of lateral stirrups were also within the investigated parameters. Four solid beams in addition to 10 hollow beams with central square holes with side lengths of 60, 80, and 100 mm were fabricated to evaluate the test parameters. These beams were either reinforced with 1% steel fiber or contain no fiber. The flexural performance of the beams was evaluated using the load–deflection behavior, flexural ductility, stiffness and toughness. In addition to the experimental work, analytical formulas were introduced to evaluate the cracking and peak loads of the hollow beams. The test results showed that ductility of hollow beams with size reductions of 16% and 28.4% was higher than that of the reference solid beam, while the ductility of the hollow beam with 44.4% size reduction was quite comparable to that of the solid beam. Moreover, the toughness values of the hollow beams were higher by 19 to 37% than that of the reference solid beam. Based on the obtained results, it can be concluded that hollow reinforced concrete beams with 1.0% steel fiber and with size reduction up to 44.4% can replace solid beams without suffering significant reductions in strength, ductility and toughness.

In this paper, a coupled thermo-hydro-mechanical (THM) simulation in a faulted deformable porous medium is presented. This model involves solving the mass conservation, linear momentum balance, and energy balance equations which are derived from the Biot's consolidation theory. Fluid pore pressure, solid displacement, and temperature are chosen as initial variables in these equations, and the finite element method in combination with the interface element is used for spatial discretization of continuous and discontinuities (fault) parts of the medium to solve the equations. The main purpose of this study is providing precise formulations, applicability, and ability of the triple-node zero-thickness interface element in THM modeling of faults. It should be noted that the system of equations is solved using a computer code written in Matlab program. In order to verify the developed method, simulations of index problems such as Mandel's problem, and coupled modeling of a faulted porous medium and a faulted aquifer are presented. The modeling results obtained from the developed method show a very good agreement with those by other modeling methods, which indicates its accuracy. Keywords: Thermo-hydro-mechanical (THM) simulation, Geomechanical coupling, Zero-thickness element, Joint element, Finite element

In this paper, the effect of using three solar fields in a solar thermal power plant has been evaluated. Two separate solar direct steam generations are used to provide a portion of the energy required by the high-pressure turbine and low-pressure turbine. The third solar field is used for molten salt energy storage. If the energy stored during the daytime is not enough, the fossil fuel boiler will provide the rest of the energy needed. Given the current price of natural gas, the use of solar energy is not cost-effective, regardless of environmental issues, government incentives or external costs, such as health costs. Furthermore, the use of solar energy for the power plant was unable to make a significant reduction in electricity cost, regardless the 3.5$/MMBTU natural gas price. However, considering the complexity of the solar system, the use of solar energy for the price of the current natural gas is not recommended. By increasing the price of natural gas, the use of solar energy is more economically feasible. The results of the study show that the use of three solar fields (two separate solar fields to produce superheated steam for a high-pressure turbine and low-pressure turbine and a solar field for energy storage using molten salt as thermal energy storage medium) rather than one solar field reduces electricity consumption by 1.83%–13.78% for the price of 9 $/MMBtu natural gas. Although each of the first and second solar fields produce different energy quantities, and therefore, require different field areas, the field coefficient of the field is the same for both solar fields.

This paper presents the development of a probabilistic seismic hazard analysis (PSHA) model to compute seismic hazard maps for the French territory taking into account 15 years of research and development in the area. Since 2002, when the first probabilistic hazard map was computed for France, many new data became available leading to new studies and experience gained. This 2017 PSHA version for France incorporates significant improvements over previous version. In particular, the recent SIGMA project 2010–2016 produced a number of outputs which are used in the present analysis: a homogenized earthquake catalogue in moment magnitude (Mw), a Bayesian methodology to compute distributions of maximum magnitudes, ground motion prediction equations specifically developed for the French territory, new seismotectonic analysis conducted based on geological, structural, geophysical, neotectonic and seismological data. Preliminary comparison of median PGA values at 475 years return period with results obtained independently for neighboring countries (Germany, Switzerland, and Italy) reveals a fair agreement. Comparison with the 2013 European Seismic Hazard Model (ESHM13, SHARE project) and the model for France developed in 2002 indicates that 2017 PSHA version leads to lower hazard.

The functionalisation of carbon nanotubes (CNTs) with biomolecules in an aqueous environment has found considerable potential applications in nanobiotechnology. To understand the structural propert...

This research for the first time presents the possibility of crossing the biologically produced SNPs through the placenta to different organs of rat offspring. SNPs were produced using Fusarium oxysporum. After adding 1 mmol final concentration of silver nitrate solution to the culture supernatant and 5 min heating, SNPs were produced, and their production was proved using visible spectrum, transmission electron microscope (TEM), and X-ray diffraction (XRD) analyses. SNPs were washed, and their concentration determined using inductively coupled plasma (ICP) instrument. SNPs were used for 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and after determination of their half maximal inhibitory concentration (IC50) dose, their toxic and nontoxic doses were determined and used for in vivo studies. A total of 24 female rats, after detection of their vaginal plugs, were divided into 3 groups each having 8 members. A control group was treated with normal saline. The other two groups were treated by toxic and nontoxic doses of SNPs, respectively. After delivery and breastfeeding, the pups were scarified, and their organs were collected and analyzed using histological examinations. Results showed that SNPs had a maximum absorbance peak around 450 nm, with polygonal and round shapes. XRD results confirmed the presence of SNPs. The concentration of the SNPs after washing was 19 ppm/mL based on the ICP results. MTT assay results showed that SNPs had a dose-dependent toxic effect. Histopathological examination results showed that SNPs could pass through the placenta; both their nontoxic and toxic doses induced somehow mild alternations in the liver, kidney, testis, and ovary and had no effects on the brains of the rat offspring. In conclusions, the use of the biologically produced SNPs should be limited during pregnancy and breastfeeding.

Frequency response analysis (FRA) is a tool for evaluating mechanical integrity of transformer's core and winding. However, several studies have reported that FRA is also sensitive to other parameters such as temperature, moisture content and presence of oil. Since some of these parameters are critical in the insulation degradation process, it is interesting to further investigate the possibility of using FRA for insulation assessment. In this paper, the insulation conditions of three field transformers are investigated using FRA. This is performed after statistical analysis on the response suggested no mechanical damage on the transformers. The responses are further analyzed to determine the percentage of change of winding capacitance. This is achieved by comparing resonance frequencies between the responses. The percentage of change represents the amount of degradation in the insulation. This is because as the insulation condition degrades, the response is shifted towards lower frequencies. This new investigation demonstrates the applicability of FRA to estimate the insulation degradation.

Although having too many details can complicate the planning process, this study involves the formulating of an executive model having a broad range of parameters aimed at network-level pavement maintenance and rehabilitation planning. Four decomposed indicators are used to evaluate the pavement conditions and eight maintenance and rehabilitation categories are defined using these pavement quality indicators. As such, some restrictions called ''technical constraints" are defined to reduce complexity of solving procedure. Using the condition indicators in the form of normalized values and developing technical constraints in a linear integer programming model has improved network level pavement M&R planning. The effectiveness of the developed model was compared by testing it under with-and-without technical constraints conditions over a 3-year planning period in a 10-section road network. It was found that using technical constraints reduced the runtime in resolving the problem by 91%, changed the work plan by 13%, and resulted in a cost increase of 1.2%. Solving runtime reduction issues can be worthwhile in huge networks or long-term planning durations.

The benefits of the electrical-based biosensor include cheap production and fast response time of detecting diseases. An interdigitated electrode (IDE) is fabricated using silver (Ag) as a metal contact that is deposited on aliminium (Al) nanoparticles doped with both zinc oxide (ZnO) and Silicon (Si) forming AZO/Si nanostructures by vacuum coater in a thermal evaporator. The electrical properties are studied as a function of frequency and voltage using I–V characteristics. Sol–gel method under annealing temperature, 500 °C is utilized to generate Al nanoparticles doped ZnO nanostructures. UV–vis spectrophotometer, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and X-ray diffractometer (XRD) are used for analyzing optical, topographical, morphological and structural studies of AZO nanostructure, respectively. Specific empirical models of optical dielectric constant, bulk modulus and refractive index are also verified. PACS: 75.75.Fk, 77.55.hf, 87.85.fk, 88.10.gp, Keywords: AZO, Sol–gel method, Characterization, Optical

BaWO4 nanoparticles and BaWO4/CdMoO4 nanocomposites were synthesized by eco-friendly method at low temperature. The effects of various capping agents such as glucose, fructose, lactose, and starch on the morphology and particle size of BaWO4/CdMoO4 nanocomposites were investigated. The nanocluster was obtained with glucose and Ba2+ to capping agent molar ratio of (1:2). BaWO4/CdMoO4 nanocomposites were analyzed through techniques including, XRD, FT-IR, VSM, TEM, PL, FESEM, UV–vis, and EDX. According to the BET results, in the presence of glucose as the capping agent, surface area increased from 13.781 m2/g to 122.22 m2/g. Furthermore, adding CdMoO4 nanoparticles to BaWO4 causes optical properties and photocatalytic activity of BaWO4 to improve. Moreover, the effects of several factors such as BaWO4/CdMoO4 nanocomposites concentration and its particle size and difference dyes on the photocatalytic performance of BaWO4/CdMoO4 nanocomposites were studied under visible light. Keywords: BaWO4/CdMoO4, Visible light, Nanocomposites, Eco-friendly method

The transient conduct of compressor stations, especially subject to sudden change in conditions, and its effect on performance of natural gas transmission pipeline is one of the most important concerns of operators. The main objective of this paper is to investigate how compressors are arranged in compressor stations, when there is not any standby compressor. Both parallel and series mode have been analyzed for the transient state and it has been determined which of them has more advantages. Considering the boundary conditions in critical conditions, the series arrangement compared to parallel, provides a longer period for the needs of consumers.