This paper presents a novel artificial intelligence (AI) based approach to predict crucial meteorological parameters such as temperature,pressure,and wind speed,typically calculated from computationally intensive weat...This paper presents a novel artificial intelligence (AI) based approach to predict crucial meteorological parameters such as temperature,pressure,and wind speed,typically calculated from computationally intensive weather research and forecasting (WRF) model.Accurate meteorological data is indispensable for simulating the release of radioactive effluents,especially in dispersion modeling for nuclear emergency decision support systems.Simulation of meteorological conditions during nuclear emergencies using the conventional WRF model is very complex and time-consuming.Therefore,a new artificial neural network (ANN) based technique was proposed as a viable alternative for meteorological prediction.A multi-input multi-output neural network was trained using historical site-specific meteorological data to forecast the meteorological parameters.Comprehensive evaluation of this technique was conducted to test its performance in forecasting various parameters including atmospheric pressure,temperature,and wind speed components in both East-West and North-South directions.The performance of developed network was evaluated on an unknown dataset,and acquired results are within the acceptable range for all meteorological parameters.Results show that ANNs possess the capability to forecast meteorological parameters,such as temperature and pressure,at multiple spatial locations within a grid with high accuracy,utilizing input data from a single station.However,accuracy is slightly compromised when predicting wind speed components.Root mean square error (RMSE) was utilized to report the accuracy of predicted results,with values of 1.453℃for temperature,77 Pa for predicted pressure,1.058 m/s for the wind speed of U-component and 0.959 m/s for the wind speed of V-component.In conclusion,this approach offers a precise,efficient,and wellinformed method for administrative decision-making during nuclear emergencies.展开更多
The International Skin Imaging Collaboration(ISIC)datasets are pivotal resources for researchers in machine learning for medical image analysis,especially in skin cancer detection.These datasets contain tens of thousa...The International Skin Imaging Collaboration(ISIC)datasets are pivotal resources for researchers in machine learning for medical image analysis,especially in skin cancer detection.These datasets contain tens of thousands of dermoscopic photographs,each accompanied by gold-standard lesion diagnosis metadata.Annual challenges associated with ISIC datasets have spurred significant advancements,with research papers reporting metrics surpassing those of human experts.Skin cancers are categorized into melanoma and non-melanoma types,with melanoma posing a greater threat due to its rapid potential for metastasis if left untreated.This paper aims to address challenges in skin cancer detection via visual inspection and manual examination of skin lesion images,processes historically known for their laboriousness.Despite notable advancements in machine learning and deep learning models,persistent challenges remain,largely due to the intricate nature of skin lesion images.We review research on convolutional neural networks(CNNs)in skin cancer classification and segmentation,identifying issues like data duplication and augmentation problems.We explore the efficacy of Vision Transformers(ViTs)in overcoming these challenges within ISIC dataset processing.ViTs leverage their capabilities to capture both global and local relationships within images,reducing data duplication and enhancing model generalization.Additionally,ViTs alleviate augmentation issues by effectively leveraging original data.Through a thorough examination of ViT-based methodologies,we illustrate their pivotal role in enhancing ISIC image classification and segmentation.This study offers valuable insights for researchers and practitioners looking to utilize ViTs for improved analysis of dermatological images.Furthermore,this paper emphasizes the crucial role of mathematical and computational modeling processes in advancing skin cancer detection methodologies,highlighting their significance in improving algorithmic performance and interpretability.展开更多
Specific activity of primordial radionuclides and associated radiation hazards due to 40K, 226Ra, and 232Th have been measured in backed red brick samples, collected from five highly populated areas of the North West ...Specific activity of primordial radionuclides and associated radiation hazards due to 40K, 226Ra, and 232Th have been measured in backed red brick samples, collected from five highly populated areas of the North West Frontier Province of Pakistan. For the detection, analysis and data acquisition, a high purity germanium detector was used. Associated external doses were calculated using a Monte Carlo neutron photon transport code. A theoretical model to determine the gamma dose rate at 1 m height from the floor, made of bricks, was employed for the calculation of mass attenuation coefficient and self-absorption in the floor for the gamma energies of these radionuclides and their progeny. Monte Carlo simulation shows that in this study the floor, having more than an effective thickness of 15 cm, contributes very little to the external gamma dose rate. The values of the external dose rate and annual effective dose are found to be much lower than the world average as well as from other countries of the world.展开更多
BACKGROUND Hepatitis C virus genotype 3a(HCV G3a)is highly prevalent in Pakistan.Due to the elevated cost of available Food and Drug Administration-approved drugs against HCV,medicinal natural products of potent antiv...BACKGROUND Hepatitis C virus genotype 3a(HCV G3a)is highly prevalent in Pakistan.Due to the elevated cost of available Food and Drug Administration-approved drugs against HCV,medicinal natural products of potent antiviral activity should be screened for the cost-effective treatment of the disease.Furthermore,from natural products,active compounds against vital HCV proteins like non-structural protein 3(NS3)protease could be identified to prevent viral proliferation in the host.AIM To develop cost-effective HCV genotype 3a NS3 protease inhibitors from citrus fruit extracts.METHODS Full-length NS3 without co-factor non-structural protein 4A(NS4A)and codon optimized NS3 protease in fusion with NS4A were expressed in Escherichia coli.The expressed protein was purified by metal ion affinity chromatography and gel filtration.Citrus fruit extracts were screened using fluorescence resonance energy transfer(FRET)assay against the protease and polyphenols were identified as potential inhibitors using electrospray ionization-mass spectrometry(MS)/MS technique.Among different polyphenols,highly potent compounds were screened using molecular modeling approaches and consequently the most active compound was further evaluated against HCV NS4A-NS3 protease domain using FRET assay.RESULTS NS4A fused with NS3 protease domain gene was overexpressed and the purified protein yield was high in comparison to the lower yield of the full-length NS3 protein.Furthermore,in enzyme kinetic studies,NS4A fused with NS3 protease proved to be functionally active compared to full-length NS3.So it was concluded that co-factor NS4A fusion is essential for the purification of functionally active protease.FRET assay was developed and validated by the half maximal inhibitory concentration(IC50)values of commercially available inhibitors.Screening of citrus fruit extracts against the native purified fused NS4A-NS3 protease domain showed that the grapefruit mesocarp extract exhibits the highest percentage inhibition 91%of protease activity.Among the compounds identified by LCMS analysis,hesperidin showed strong binding affinity with the protease catalytic triad having S-score value of-10.98.CONCLUSION Fused NS4A-NS3 protease is functionally more active,which is effectively inhibited by hesperidin from the grapefruit mesocarp extract with an IC50 value of 23.32μmol/L.展开更多
Chromium nitride （Cr2N） thin films were prepared by a DC magnetron sputtering technique. The deposition temperature was raised from 50 to 300℃, and its influence on the film structure and refractive index was inves...Chromium nitride （Cr2N） thin films were prepared by a DC magnetron sputtering technique. The deposition temperature was raised from 50 to 300℃, and its influence on the film structure and refractive index was investigated. X-ray diffraction analysis shows that the crystalline strucure of the films transforms from the （101） to （002） oriented hexagonal CrzN phase as the increase of substrate tempera- ture above 50℃, and a highly texatred film grows at 100℃. An empirical relation between the crystalline orientation and infrared active modes of the films is obtained, i.e., the Fourier transform infrared （FTIR） spectrum of the film prepared at 50℃ exhibits only A1 （TO） mode. The prominent peak in the FTIR spectra of the film prepared above 50℃is assigned to the E1 （TO） mode and is correlated with the （002） or c-axis oriented hexagonal wurtzite phase of Cr2N. In the surface analysis of atomic force microscopy, a transformation from the featureless surface to columnar-type morphology is observed with the increase of substrate temperature from 50 to 100℃, exhibiting c-axis oriented crystallite growth. A further increase in substrate temperature to 200℃ causes the c-axis crystallites to merge, resulting in the formation of voids. The refractive index （n） of the deposited films is obtained using spectroscopic ellipsometry.展开更多
Aluminum matrix composites(AMCs), reinforced with novel pre-synthesized Al/Cu Fe multi-layered coreshell particles, were fabricated by different consolidation techniques to investigate their effect on microstructure a...Aluminum matrix composites(AMCs), reinforced with novel pre-synthesized Al/Cu Fe multi-layered coreshell particles, were fabricated by different consolidation techniques to investigate their effect on microstructure and mechanical properties. To synthesize multi-layered Al/Cu Fe core-shell particles, Cu and Fe layers were deposited on Al powder particles by galvanic replacement and electroless plating method, respectively. The core-shell powder and sintered compacts were characterized by using X-ray diffraction(XRD), scanning electron microscopy(SEM) equipped with energy dispersive spectroscopy(EDX), pycnometer, microhardness and compression tests. The results revealed that a higher extent of interfacial reactions, due to the transformation of the deposited layer into intermetallic phases in spark plasma sintered composite, resulted in high relative density(99.26%), microhardness(165 HV0.3) and strength(572 MPa). Further, the presence of un-transformed Cu in the shell structure of hot-pressed composite resulted in the highest fracture strain(20.4%). The obtained results provide stronger implications for tailoring the microstructure of AMCs through selecting appropriate sintering paths to control mechanical properties.展开更多
High pressure investigations of matter involve the study of strong shock wave dynamics within the materials which gives rise to many thermal effects leading to dissociation of molecules,ionization of atoms,and radiati...High pressure investigations of matter involve the study of strong shock wave dynamics within the materials which gives rise to many thermal effects leading to dissociation of molecules,ionization of atoms,and radiation emission,etc.The response of materials experiencing a strong shock can be determined by its shock Hugoniot calculations which are frequently applied in numerical and experimental studies in inertial confinement fusion,laboratory astrophysical plasma,etc.These studies involve high energy density plasmas in which the radiation plays an important role in determining the energy deposition and maximum compressibility achieved by the shock within material.In this study,we present an investigation for the effect of radiation pressure on the maximum compressibility of the material using shock Hugoniot calculations.In shock Hugoniot calculations,an equation of state(EOS)is developed in which electronic contributions for EOS calculations are taken from an improved screened hydrogenic model with−l splitting(I-SHML)[High Energy Density Physics(2018)2648]under local thermodynamic equilibrium(LTE)conditions.The thermal ionic part calculations are adopted from the state of the art Cowan model while the cold ionic contributions are adopted from the scaled binding energy model.The Shock Hugoniot calculations are carried out for sodium and iron plasmas and our calculated results show excellent agreement with published results obtained by using either sophisticated self-consistent models or the first principle study.展开更多
The structural, electronic, and optical properties of Zn3（VO4）2 are investigated using full potential linearized aug- mented plane wave （FP-LAPW） method within the framework of density functional theory （DFT）. V...The structural, electronic, and optical properties of Zn3（VO4）2 are investigated using full potential linearized aug- mented plane wave （FP-LAPW） method within the framework of density functional theory （DFT）. Various approaches are adopted to treat the exchange and correlation potential energy such as generalized gradient approximation （GGA）, GGA＋U, and the Tran-Blaha modified Becke-Johnson （TB-mBJ） potential. The calculated band gap of 3.424 eV by TB- mBJ is found to be close to the experimental result （3.3 eV）. The optical anisotropy is analyzed through optical constants, such as dielectric function and absorption coefficient along parallel and perpendicular crystal orientations. The absorption coefficient reveals high absorption （1.5 ×10^6cm^-1） of photons in the ultraviolet region.展开更多
An alloy having composition Fe73Si13B9Nb4Cu1 was synthesized by melt spinning to investigate the kinetics of crystallization. Techniques of differential scanning calorimetry （DSC）, X-ray diffraction （XRD） and Moss...An alloy having composition Fe73Si13B9Nb4Cu1 was synthesized by melt spinning to investigate the kinetics of crystallization. Techniques of differential scanning calorimetry （DSC）, X-ray diffraction （XRD） and Mossbauer spectroscopy were employed to characterize the phases produced due to annealing at various temperatures. High temperature DSC revealed two stage crystallization reactions. First stage, crystallization occurs at temperature around 514℃ with the production of α-Fe （bcc） and Fe3Si phases. In the second stage, Fe2B and α-Fe （Si,Nb） phases were produced. Mossbauer results revealed the formation of Fe3Si, Fe13Si3 and Fe7Si1 in the first stage and Fe3Si, Fe13Si3, Fe2B and α-Fe （Si,Nb） phases in the second stage of crystallization. An abrupt change in average internal magnetic field was observed at 500℃. The maximum hardness value was found for the sample heat-treated at 500℃.展开更多
This paper addresses the control law design for synchronization of two different chaotic oscillators with mutually Lipschitz nonlinearities. For analysis of the properties of two different nonlinearities, an advanced ...This paper addresses the control law design for synchronization of two different chaotic oscillators with mutually Lipschitz nonlinearities. For analysis of the properties of two different nonlinearities, an advanced mutually Lipschitz condition is proposed. This mutually Lipschitz condition is more general than the traditional Lipschitz condition. Unlike the latter, it can be used for the design of a feedback controller for synchronization of chaotic oscillators of different dynamics. It is shown that any two different Lipschitz nonlinearities always satisfy the mutually Lipschitz condition. Applying the mutually Lipschitz condition, a quadratic Lyapunov function and uniformly ultimately bounded stability, easily designable and implementable robust control strategies utilizing algebraic Riccati equation and linear matrix inequalities, are derived for synchronization of two distinct chaotic oscillators. Furthermore, a novel adaptive control scheme for mutually Lipschitz chaotic systems is established by addressing the issue of adaptive cancellation of unknown mismatch between the dynamics of different chaotic systems. The proposed control technique is numerically tested for synchronization of two different chaotic Chua＇s circuits and for obtaining identical behavior between the modified Chua＇s circuit and the R6ssler system.展开更多
We report the hydrothermal growth of pure and doped TiO2 nanoparticles with different concentrations of carbon.The microstructure of the as-synthesized samples is characterized by x-ray diffraction(XRD),field emission...We report the hydrothermal growth of pure and doped TiO2 nanoparticles with different concentrations of carbon.The microstructure of the as-synthesized samples is characterized by x-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),energy dispersive x-ray spectroscopy(EDX),and Raman spectroscopy to understand the structure and composition.The XRD patterns confirm the formation of anatase phase of TiO2 with the average crystallite size is calculated to be in the range of 13 nm to 14.7 nm.The functional groups of these nanostructures are characterized by Fourier transformed infrared(FT-IR)spectroscopy,which further confirms the single anatase phase of the synthesized nanostructures.UV-visible absorption spectroscopy is used to understand the absorption behavior,which shows modification in the optical bandgap from 3.13 eV(pure TiO2)to 3.74 eV(1.2 mol%C-doped TiO2).Furthermore,the Ti^3+centers associated with oxygen vacancies are identified using electron paramagnetic resonance spectroscopy(EPR).展开更多
The study of buoyancy driven flow within bottom-heated vertical concentric cylindrical enclosure was important with respect to the processes in chemical and nuclear industries. In this research paper, experimental and...The study of buoyancy driven flow within bottom-heated vertical concentric cylindrical enclosure was important with respect to the processes in chemical and nuclear industries. In this research paper, experimental and numerical study of the axial temperature gradient and the heat transfer mechanism within the enclosure were performed. The numerical simulations were validated by comparing the numerical results with experimentally measured axial temperature. The numerical results of the streamlines within the enclosure depicted the real picture of the buoyancy effects. Eighteen different experiments were performed by using inner cylinder of different materials and outer cylinder of different diameters within the bottom disc temperature range of 353 - 433 K. The CFD simulations were performed to study the buoyancy effects within the enclosure. At the bottom disc with temperature up to 393 K, the streamlines within the inner cylinder were almost the same for both con- figurations being independent of outer cylinder diameter, while at 433 K streamlines within the inner cylinders varied. With larger diameter outer cylinder configuration, the buoyancy effects in the outer annulus were stronger as compared to smaller one.展开更多
The heat transfer of supercritical fluids is a vastly growing field, specifically to find suitable <span style="font-family:Verdana;">alternative to replace conventional R134a, which can be beneficial ...The heat transfer of supercritical fluids is a vastly growing field, specifically to find suitable <span style="font-family:Verdana;">alternative to replace conventional R134a, which can be beneficial for climate change. A </span><span style="font-family:Verdana;">considerable suggestion is R515A which possesses considerably lower global warming potential. The present simulations are designed to study supercritical fluid R515A under cooling conditions in horizontal position. The effect of pressure, mass flux, heat flux and tube diameter were considered for horizontal tube in the vicinity of pseudo critical temperature. Numeri</span><span style="font-family:Verdana;">cal investigations on heat transfer characteristics of supercritical fluid R515A were per</span><span style="font-family:Verdana;">formed using widely used shear-stress transport (SST) model. Moreover, heat transfer correlations </span><span style="font-family:Verdana;">were developed and suggested to accurately predict Nusselt number within 10% accuracy. </span><span style="font-family:Verdana;">The simulation results showed about 3.98% average absolute deviation.</span>展开更多
We performed R-matrix calculations for photoionization cross sections of the two ground state configuration 3s^23p^5（~2P_（3/2,1/2）~o） levels and 12 excited states of Ni Ⅻ using relativistic Dirac Atomic R-matrix ...We performed R-matrix calculations for photoionization cross sections of the two ground state configuration 3s^23p^5（~2P_（3/2,1/2）~o） levels and 12 excited states of Ni Ⅻ using relativistic Dirac Atomic R-matrix Codes（DARC） across the photon energy range between the ionizations thresholds of the corresponding states and well above the thresholds of the last level of the Ni XIII target ion. Generally, a good agreement is obtained between our results and the earlier theoretical photoionization cross sections. Moreover, we have used two independent fully relativistic GRASP and FAC codes to calculate fine-structure energy levels, wavelengths, oscillator strengths, transitions rates among the lowest 48 levels belonging to the configuration（3s^23p^4, 3s3p^5, 3p^6, 3s^23p^33d） in Ni XIII. Additionally, radiative lifetimes of all the excited states of Ni XIII are presented. Our results of the atomic structure of Ni XIII show good agreement with other theoretical and experimental results available in the literature. A good agreement is found between our calculated lifetimes and the experimental ones.Our present results are useful for plasma diagnostic of fusion and astrophysical plasmas.展开更多
Ionizing radiations are widely used to sustain and enhance our quality of life in the areas such as medical diagnosis, therapy, scientific research and industry etc. Ionizing radiations are available from radioactive ...Ionizing radiations are widely used to sustain and enhance our quality of life in the areas such as medical diagnosis, therapy, scientific research and industry etc. Ionizing radiations are available from radioactive sources which are made of radioactive materials. The radioactive materials are produced in either nuclear power or research reactors or nuclear accelerators or extracted from the naturally found radioactive ores. These radioactive sources and radioactive materials need to be transported from their places of production to the places of applications and finally to waste repositories. The radioactive materials are transported in well designed packages having various shapes and sizes. In the field of radioactive transport, it is a mandatory to find the Transport Index (TI) to be mentioned on each package for transportation. This research is focused on the determination of the maximum γ-ray radiation dose at one meter from the surface of cubic and rectangular shaped package or containers. A computer code “Solid Angle for Transport Index” (SAFTI) has been developed using MATLAB to determine the location of maximum value of the radiation dose rate from the surface of a rectangular or square container. This maximum dose rate is used to determine the transport index. Some of the results of the code have been compared with the experimental results. The results of this research are useful not only to determine TI for individual packages but also to find the TI of the vehicles carrying the transport packages.展开更多
In this paper,an experimental study of laminar,steady state natural convection heat transfer from heated thin cylinders in an infinite air medium has been reported.Two electrically heated cylinders having the same sle...In this paper,an experimental study of laminar,steady state natural convection heat transfer from heated thin cylinders in an infinite air medium has been reported.Two electrically heated cylinders having the same slenderness ratio(L/D)i.e.6.1 but different diameters i.e.3.8 cm and 5.08 cm were used.105 experiments were carried out to study the effect of diameter and inclination angle of thin cylinder on natural convection heat transfer.After mandatory corrections of radiation and endcap heat losses,convective heat transfer results were presented in the form of local and average dimensionless numbers.For vertical configuration of thin cylinder,Nusselt number was varied from 52.99 to 95.10 corresponding to 1.28×10^(8)≤Ra*L≤1.08×10^(10).While for horizontal configuration,Nusselt number was varied from 10.74 to 17.78 corresponding to 9.42×10^(4)≤Ra*D≤8.17×10^(6).Results were compared with the published data and found satisfactory as the maximum percentage difference was only 3.09%.The essence of research is that the heat transfer coefficient increases with decrease in diameter and increase in inclination angle.Smoke flow visualization was done to capture patterns of fluid flow.Finally,comparison was made to quantify increase in Nusselt number from slender cylinder as compared to the flat plate.展开更多
The phenomenon of direct-contact condensation,used in steam driven jet injectors,nuclear reactor emergency core cooling systems and direct-contact heat exchangers,was investigated computationally by introducing a ther...The phenomenon of direct-contact condensation,used in steam driven jet injectors,nuclear reactor emergency core cooling systems and direct-contact heat exchangers,was investigated computationally by introducing a thermal equilibrium model for direct-contact condensation of steam in subcooled water.The condensation model presented was a two resistance model which takes care of the heat transfer process on both sides of the interface and uses a variable steam bubble diameter.The injection of supersonic steam jet in subcooled water tank was simulated using the Euler-Euler multiphase flow model of Fluent 6.3 code with the condensation model incorporated. The findings of the computational fluid dynamics（CFD） simulations were compared with the published experimental data and fairly good agreement was observed between the two,thus validating the condensation model.The results of CFD simulations for dimensionless penetration length of steam plume varies from 2.73-7.33,while the condensation heat transfer coefficient varies from 0.75-0.917 MW·（m ^2 ·K）^ -1 for water temperature in the range of 293-343 K.展开更多
Silver nanoparticles of mean size 16 nm were synthesized by inert gas condensation （IGC） method. Crystalline structure, morphology and nanoparticles size estimation were conducted by X-ray diffraction （XRD） and tr...Silver nanoparticles of mean size 16 nm were synthesized by inert gas condensation （IGC） method. Crystalline structure, morphology and nanoparticles size estimation were conducted by X-ray diffraction （XRD） and transmission electron microscopy （TEM）. Antibacterial activity of these silver nanoparticles as a function of particles concentration against gram-negative bacterium Escherichia coli （E. coli） was carried out in liquid as well as solid growth media. Scanning electron microscopy （SEM） and TEM studies showed that silver nanoparticles after interaction with E.coli have adhered to and penetrated into the bacterial cells. Antibacterial properties of silver nanoparticles are attributed to their total surface area, as a larger surface to volume ratio of nanoparticles provides more efficient means for enhanced antibacterial activity.展开更多
The heat transfer of supercritical fluids is a vastly growing field, specifically to find suitable alternatives to replace conventional R134a, which can be beneficial for climate change. Most of the experimental and n...The heat transfer of supercritical fluids is a vastly growing field, specifically to find suitable alternatives to replace conventional R134a, which can be beneficial for climate change. Most of the experimental and numerical investigations have been conducted to explore supercritical water, carbon dioxide and R134a as heat transfer working fluids. Hydrofluoroolefin (HFO) and refrigerants blends have been considered the most environment-friendly refrigerants to replace Chlorofluorocarbons (CFCs), Hydrochlorofluoro-carbons (HCFCs) and Hydrofluorocarbons (HFCs). Their main advantage of zero Ozone Depletion Potential (ODP) and comparatively lower Global Warming Potential (GWP) have attracted growing amount of attention to mitigate environmental issues. This work adopts the computational method and takes the environmentally friendly refrigerants to investigate the heat transfer characteristics under widely used shear-stress transport (SST) model. A comprehensive comparison was performed at reduced pressure of 1.10 for supercritical fluids R515A, R1234ze(E) and R134a. The peaks of heat transfer coefficient occurred in the vicinity of pseudo critical temperature for all of these considered fluids;however, R134a resulted in higher heat transfer coefficient, Reynolds number and Prandtl number in comparison with R515A and R1234ze(E). The higher heat transfer coefficient of supercritical fluid R134a is owing to its thermophysical properties and the specific heat plays crucial role in the heat transfer of supercritical fluids. Owing to environmental issues, R515A can be a considerable replacement of R134a. R1234ze(E) is also promising alternative to R134a;however, safety issues should thoroughly concern its mild flammable characteristics.展开更多
Fuel reload pattern optimization is essential for attaining maximum fuel burnup for minimization of generation cost while minimizing power peaking factor(PPF).The aim of this work is to carry out detailed assessment o...Fuel reload pattern optimization is essential for attaining maximum fuel burnup for minimization of generation cost while minimizing power peaking factor(PPF).The aim of this work is to carry out detailed assessment of particle swarm optimization(PSO) in the context of fuel reload pattern search. With astronomically large number of possible loading patterns, the main constraints are limiting local power peaking factor, fixed number of assemblies,fixed fuel enrichment, and burnable poison rods. In this work, initial loading pattern of fixed batches of fuel assemblies is optimized by using particle swarm optimization technique employing novel feature of varying inertial weights with the objective function to obtain both flat power profile and cycle k_(eff)>1. For neutronics calculation, PSU-LEOPARD-generated assembly depletiondependent group-constant-based ADD files are used. The assembly data description file generated by PSU-LEOPARD is used as input cross-section library to MCRAC code, which computes normalized power profile of all fuel assemblies of PWR nuclear reactor core. The standard PSO with varying inertial weights is then employed to avoid trapping in local minima. A series of experiments havebeen conducted to obtain near-optimal converged fuelloading pattern of 300 MWe PWR Chashma reactor. The optimized loading pattern is found in good agreement with results found in literature. Hybrid scheme of PSO with simulated annealing has also been implemented and resulted in faster convergence.展开更多
文摘This paper presents a novel artificial intelligence (AI) based approach to predict crucial meteorological parameters such as temperature,pressure,and wind speed,typically calculated from computationally intensive weather research and forecasting (WRF) model.Accurate meteorological data is indispensable for simulating the release of radioactive effluents,especially in dispersion modeling for nuclear emergency decision support systems.Simulation of meteorological conditions during nuclear emergencies using the conventional WRF model is very complex and time-consuming.Therefore,a new artificial neural network (ANN) based technique was proposed as a viable alternative for meteorological prediction.A multi-input multi-output neural network was trained using historical site-specific meteorological data to forecast the meteorological parameters.Comprehensive evaluation of this technique was conducted to test its performance in forecasting various parameters including atmospheric pressure,temperature,and wind speed components in both East-West and North-South directions.The performance of developed network was evaluated on an unknown dataset,and acquired results are within the acceptable range for all meteorological parameters.Results show that ANNs possess the capability to forecast meteorological parameters,such as temperature and pressure,at multiple spatial locations within a grid with high accuracy,utilizing input data from a single station.However,accuracy is slightly compromised when predicting wind speed components.Root mean square error (RMSE) was utilized to report the accuracy of predicted results,with values of 1.453℃for temperature,77 Pa for predicted pressure,1.058 m/s for the wind speed of U-component and 0.959 m/s for the wind speed of V-component.In conclusion,this approach offers a precise,efficient,and wellinformed method for administrative decision-making during nuclear emergencies.
文摘The International Skin Imaging Collaboration(ISIC)datasets are pivotal resources for researchers in machine learning for medical image analysis,especially in skin cancer detection.These datasets contain tens of thousands of dermoscopic photographs,each accompanied by gold-standard lesion diagnosis metadata.Annual challenges associated with ISIC datasets have spurred significant advancements,with research papers reporting metrics surpassing those of human experts.Skin cancers are categorized into melanoma and non-melanoma types,with melanoma posing a greater threat due to its rapid potential for metastasis if left untreated.This paper aims to address challenges in skin cancer detection via visual inspection and manual examination of skin lesion images,processes historically known for their laboriousness.Despite notable advancements in machine learning and deep learning models,persistent challenges remain,largely due to the intricate nature of skin lesion images.We review research on convolutional neural networks(CNNs)in skin cancer classification and segmentation,identifying issues like data duplication and augmentation problems.We explore the efficacy of Vision Transformers(ViTs)in overcoming these challenges within ISIC dataset processing.ViTs leverage their capabilities to capture both global and local relationships within images,reducing data duplication and enhancing model generalization.Additionally,ViTs alleviate augmentation issues by effectively leveraging original data.Through a thorough examination of ViT-based methodologies,we illustrate their pivotal role in enhancing ISIC image classification and segmentation.This study offers valuable insights for researchers and practitioners looking to utilize ViTs for improved analysis of dermatological images.Furthermore,this paper emphasizes the crucial role of mathematical and computational modeling processes in advancing skin cancer detection methodologies,highlighting their significance in improving algorithmic performance and interpretability.
文摘Specific activity of primordial radionuclides and associated radiation hazards due to 40K, 226Ra, and 232Th have been measured in backed red brick samples, collected from five highly populated areas of the North West Frontier Province of Pakistan. For the detection, analysis and data acquisition, a high purity germanium detector was used. Associated external doses were calculated using a Monte Carlo neutron photon transport code. A theoretical model to determine the gamma dose rate at 1 m height from the floor, made of bricks, was employed for the calculation of mass attenuation coefficient and self-absorption in the floor for the gamma energies of these radionuclides and their progeny. Monte Carlo simulation shows that in this study the floor, having more than an effective thickness of 15 cm, contributes very little to the external gamma dose rate. The values of the external dose rate and annual effective dose are found to be much lower than the world average as well as from other countries of the world.
文摘BACKGROUND Hepatitis C virus genotype 3a(HCV G3a)is highly prevalent in Pakistan.Due to the elevated cost of available Food and Drug Administration-approved drugs against HCV,medicinal natural products of potent antiviral activity should be screened for the cost-effective treatment of the disease.Furthermore,from natural products,active compounds against vital HCV proteins like non-structural protein 3(NS3)protease could be identified to prevent viral proliferation in the host.AIM To develop cost-effective HCV genotype 3a NS3 protease inhibitors from citrus fruit extracts.METHODS Full-length NS3 without co-factor non-structural protein 4A(NS4A)and codon optimized NS3 protease in fusion with NS4A were expressed in Escherichia coli.The expressed protein was purified by metal ion affinity chromatography and gel filtration.Citrus fruit extracts were screened using fluorescence resonance energy transfer(FRET)assay against the protease and polyphenols were identified as potential inhibitors using electrospray ionization-mass spectrometry(MS)/MS technique.Among different polyphenols,highly potent compounds were screened using molecular modeling approaches and consequently the most active compound was further evaluated against HCV NS4A-NS3 protease domain using FRET assay.RESULTS NS4A fused with NS3 protease domain gene was overexpressed and the purified protein yield was high in comparison to the lower yield of the full-length NS3 protein.Furthermore,in enzyme kinetic studies,NS4A fused with NS3 protease proved to be functionally active compared to full-length NS3.So it was concluded that co-factor NS4A fusion is essential for the purification of functionally active protease.FRET assay was developed and validated by the half maximal inhibitory concentration(IC50)values of commercially available inhibitors.Screening of citrus fruit extracts against the native purified fused NS4A-NS3 protease domain showed that the grapefruit mesocarp extract exhibits the highest percentage inhibition 91%of protease activity.Among the compounds identified by LCMS analysis,hesperidin showed strong binding affinity with the protease catalytic triad having S-score value of-10.98.CONCLUSION Fused NS4A-NS3 protease is functionally more active,which is effectively inhibited by hesperidin from the grapefruit mesocarp extract with an IC50 value of 23.32μmol/L.
基金financially supported by the National Institute of Laser and Optronics(NILOP)
文摘Chromium nitride （Cr2N） thin films were prepared by a DC magnetron sputtering technique. The deposition temperature was raised from 50 to 300℃, and its influence on the film structure and refractive index was investigated. X-ray diffraction analysis shows that the crystalline strucure of the films transforms from the （101） to （002） oriented hexagonal CrzN phase as the increase of substrate tempera- ture above 50℃, and a highly texatred film grows at 100℃. An empirical relation between the crystalline orientation and infrared active modes of the films is obtained, i.e., the Fourier transform infrared （FTIR） spectrum of the film prepared at 50℃ exhibits only A1 （TO） mode. The prominent peak in the FTIR spectra of the film prepared above 50℃is assigned to the E1 （TO） mode and is correlated with the （002） or c-axis oriented hexagonal wurtzite phase of Cr2N. In the surface analysis of atomic force microscopy, a transformation from the featureless surface to columnar-type morphology is observed with the increase of substrate temperature from 50 to 100℃, exhibiting c-axis oriented crystallite growth. A further increase in substrate temperature to 200℃ causes the c-axis crystallites to merge, resulting in the formation of voids. The refractive index （n） of the deposited films is obtained using spectroscopic ellipsometry.
文摘Aluminum matrix composites(AMCs), reinforced with novel pre-synthesized Al/Cu Fe multi-layered coreshell particles, were fabricated by different consolidation techniques to investigate their effect on microstructure and mechanical properties. To synthesize multi-layered Al/Cu Fe core-shell particles, Cu and Fe layers were deposited on Al powder particles by galvanic replacement and electroless plating method, respectively. The core-shell powder and sintered compacts were characterized by using X-ray diffraction(XRD), scanning electron microscopy(SEM) equipped with energy dispersive spectroscopy(EDX), pycnometer, microhardness and compression tests. The results revealed that a higher extent of interfacial reactions, due to the transformation of the deposited layer into intermetallic phases in spark plasma sintered composite, resulted in high relative density(99.26%), microhardness(165 HV0.3) and strength(572 MPa). Further, the presence of un-transformed Cu in the shell structure of hot-pressed composite resulted in the highest fracture strain(20.4%). The obtained results provide stronger implications for tailoring the microstructure of AMCs through selecting appropriate sintering paths to control mechanical properties.
文摘High pressure investigations of matter involve the study of strong shock wave dynamics within the materials which gives rise to many thermal effects leading to dissociation of molecules,ionization of atoms,and radiation emission,etc.The response of materials experiencing a strong shock can be determined by its shock Hugoniot calculations which are frequently applied in numerical and experimental studies in inertial confinement fusion,laboratory astrophysical plasma,etc.These studies involve high energy density plasmas in which the radiation plays an important role in determining the energy deposition and maximum compressibility achieved by the shock within material.In this study,we present an investigation for the effect of radiation pressure on the maximum compressibility of the material using shock Hugoniot calculations.In shock Hugoniot calculations,an equation of state(EOS)is developed in which electronic contributions for EOS calculations are taken from an improved screened hydrogenic model with−l splitting(I-SHML)[High Energy Density Physics(2018)2648]under local thermodynamic equilibrium(LTE)conditions.The thermal ionic part calculations are adopted from the state of the art Cowan model while the cold ionic contributions are adopted from the scaled binding energy model.The Shock Hugoniot calculations are carried out for sodium and iron plasmas and our calculated results show excellent agreement with published results obtained by using either sophisticated self-consistent models or the first principle study.
文摘The structural, electronic, and optical properties of Zn3（VO4）2 are investigated using full potential linearized aug- mented plane wave （FP-LAPW） method within the framework of density functional theory （DFT）. Various approaches are adopted to treat the exchange and correlation potential energy such as generalized gradient approximation （GGA）, GGA＋U, and the Tran-Blaha modified Becke-Johnson （TB-mBJ） potential. The calculated band gap of 3.424 eV by TB- mBJ is found to be close to the experimental result （3.3 eV）. The optical anisotropy is analyzed through optical constants, such as dielectric function and absorption coefficient along parallel and perpendicular crystal orientations. The absorption coefficient reveals high absorption （1.5 ×10^6cm^-1） of photons in the ultraviolet region.
文摘An alloy having composition Fe73Si13B9Nb4Cu1 was synthesized by melt spinning to investigate the kinetics of crystallization. Techniques of differential scanning calorimetry （DSC）, X-ray diffraction （XRD） and Mossbauer spectroscopy were employed to characterize the phases produced due to annealing at various temperatures. High temperature DSC revealed two stage crystallization reactions. First stage, crystallization occurs at temperature around 514℃ with the production of α-Fe （bcc） and Fe3Si phases. In the second stage, Fe2B and α-Fe （Si,Nb） phases were produced. Mossbauer results revealed the formation of Fe3Si, Fe13Si3 and Fe7Si1 in the first stage and Fe3Si, Fe13Si3, Fe2B and α-Fe （Si,Nb） phases in the second stage of crystallization. An abrupt change in average internal magnetic field was observed at 500℃. The maximum hardness value was found for the sample heat-treated at 500℃.
基金supported by the Higher Education Commission of Pakistan through the Indigenous 5000 Ph.D.Fellowship Program(Phase II,Batch II)
文摘This paper addresses the control law design for synchronization of two different chaotic oscillators with mutually Lipschitz nonlinearities. For analysis of the properties of two different nonlinearities, an advanced mutually Lipschitz condition is proposed. This mutually Lipschitz condition is more general than the traditional Lipschitz condition. Unlike the latter, it can be used for the design of a feedback controller for synchronization of chaotic oscillators of different dynamics. It is shown that any two different Lipschitz nonlinearities always satisfy the mutually Lipschitz condition. Applying the mutually Lipschitz condition, a quadratic Lyapunov function and uniformly ultimately bounded stability, easily designable and implementable robust control strategies utilizing algebraic Riccati equation and linear matrix inequalities, are derived for synchronization of two distinct chaotic oscillators. Furthermore, a novel adaptive control scheme for mutually Lipschitz chaotic systems is established by addressing the issue of adaptive cancellation of unknown mismatch between the dynamics of different chaotic systems. The proposed control technique is numerically tested for synchronization of two different chaotic Chua＇s circuits and for obtaining identical behavior between the modified Chua＇s circuit and the R6ssler system.
基金The authors would like to thank the Higher Education Commission of Pakistan for providing funding(NRPU project 5349/Federal/NRPU/R&D/HEC/2016)。
文摘We report the hydrothermal growth of pure and doped TiO2 nanoparticles with different concentrations of carbon.The microstructure of the as-synthesized samples is characterized by x-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),energy dispersive x-ray spectroscopy(EDX),and Raman spectroscopy to understand the structure and composition.The XRD patterns confirm the formation of anatase phase of TiO2 with the average crystallite size is calculated to be in the range of 13 nm to 14.7 nm.The functional groups of these nanostructures are characterized by Fourier transformed infrared(FT-IR)spectroscopy,which further confirms the single anatase phase of the synthesized nanostructures.UV-visible absorption spectroscopy is used to understand the absorption behavior,which shows modification in the optical bandgap from 3.13 eV(pure TiO2)to 3.74 eV(1.2 mol%C-doped TiO2).Furthermore,the Ti^3+centers associated with oxygen vacancies are identified using electron paramagnetic resonance spectroscopy(EPR).
文摘The study of buoyancy driven flow within bottom-heated vertical concentric cylindrical enclosure was important with respect to the processes in chemical and nuclear industries. In this research paper, experimental and numerical study of the axial temperature gradient and the heat transfer mechanism within the enclosure were performed. The numerical simulations were validated by comparing the numerical results with experimentally measured axial temperature. The numerical results of the streamlines within the enclosure depicted the real picture of the buoyancy effects. Eighteen different experiments were performed by using inner cylinder of different materials and outer cylinder of different diameters within the bottom disc temperature range of 353 - 433 K. The CFD simulations were performed to study the buoyancy effects within the enclosure. At the bottom disc with temperature up to 393 K, the streamlines within the inner cylinder were almost the same for both con- figurations being independent of outer cylinder diameter, while at 433 K streamlines within the inner cylinders varied. With larger diameter outer cylinder configuration, the buoyancy effects in the outer annulus were stronger as compared to smaller one.
文摘The heat transfer of supercritical fluids is a vastly growing field, specifically to find suitable <span style="font-family:Verdana;">alternative to replace conventional R134a, which can be beneficial for climate change. A </span><span style="font-family:Verdana;">considerable suggestion is R515A which possesses considerably lower global warming potential. The present simulations are designed to study supercritical fluid R515A under cooling conditions in horizontal position. The effect of pressure, mass flux, heat flux and tube diameter were considered for horizontal tube in the vicinity of pseudo critical temperature. Numeri</span><span style="font-family:Verdana;">cal investigations on heat transfer characteristics of supercritical fluid R515A were per</span><span style="font-family:Verdana;">formed using widely used shear-stress transport (SST) model. Moreover, heat transfer correlations </span><span style="font-family:Verdana;">were developed and suggested to accurately predict Nusselt number within 10% accuracy. </span><span style="font-family:Verdana;">The simulation results showed about 3.98% average absolute deviation.</span>
文摘We performed R-matrix calculations for photoionization cross sections of the two ground state configuration 3s^23p^5（~2P_（3/2,1/2）~o） levels and 12 excited states of Ni Ⅻ using relativistic Dirac Atomic R-matrix Codes（DARC） across the photon energy range between the ionizations thresholds of the corresponding states and well above the thresholds of the last level of the Ni XIII target ion. Generally, a good agreement is obtained between our results and the earlier theoretical photoionization cross sections. Moreover, we have used two independent fully relativistic GRASP and FAC codes to calculate fine-structure energy levels, wavelengths, oscillator strengths, transitions rates among the lowest 48 levels belonging to the configuration（3s^23p^4, 3s3p^5, 3p^6, 3s^23p^33d） in Ni XIII. Additionally, radiative lifetimes of all the excited states of Ni XIII are presented. Our results of the atomic structure of Ni XIII show good agreement with other theoretical and experimental results available in the literature. A good agreement is found between our calculated lifetimes and the experimental ones.Our present results are useful for plasma diagnostic of fusion and astrophysical plasmas.
文摘Ionizing radiations are widely used to sustain and enhance our quality of life in the areas such as medical diagnosis, therapy, scientific research and industry etc. Ionizing radiations are available from radioactive sources which are made of radioactive materials. The radioactive materials are produced in either nuclear power or research reactors or nuclear accelerators or extracted from the naturally found radioactive ores. These radioactive sources and radioactive materials need to be transported from their places of production to the places of applications and finally to waste repositories. The radioactive materials are transported in well designed packages having various shapes and sizes. In the field of radioactive transport, it is a mandatory to find the Transport Index (TI) to be mentioned on each package for transportation. This research is focused on the determination of the maximum γ-ray radiation dose at one meter from the surface of cubic and rectangular shaped package or containers. A computer code “Solid Angle for Transport Index” (SAFTI) has been developed using MATLAB to determine the location of maximum value of the radiation dose rate from the surface of a rectangular or square container. This maximum dose rate is used to determine the transport index. Some of the results of the code have been compared with the experimental results. The results of this research are useful not only to determine TI for individual packages but also to find the TI of the vehicles carrying the transport packages.
文摘In this paper,an experimental study of laminar,steady state natural convection heat transfer from heated thin cylinders in an infinite air medium has been reported.Two electrically heated cylinders having the same slenderness ratio(L/D)i.e.6.1 but different diameters i.e.3.8 cm and 5.08 cm were used.105 experiments were carried out to study the effect of diameter and inclination angle of thin cylinder on natural convection heat transfer.After mandatory corrections of radiation and endcap heat losses,convective heat transfer results were presented in the form of local and average dimensionless numbers.For vertical configuration of thin cylinder,Nusselt number was varied from 52.99 to 95.10 corresponding to 1.28×10^(8)≤Ra*L≤1.08×10^(10).While for horizontal configuration,Nusselt number was varied from 10.74 to 17.78 corresponding to 9.42×10^(4)≤Ra*D≤8.17×10^(6).Results were compared with the published data and found satisfactory as the maximum percentage difference was only 3.09%.The essence of research is that the heat transfer coefficient increases with decrease in diameter and increase in inclination angle.Smoke flow visualization was done to capture patterns of fluid flow.Finally,comparison was made to quantify increase in Nusselt number from slender cylinder as compared to the flat plate.
文摘The phenomenon of direct-contact condensation,used in steam driven jet injectors,nuclear reactor emergency core cooling systems and direct-contact heat exchangers,was investigated computationally by introducing a thermal equilibrium model for direct-contact condensation of steam in subcooled water.The condensation model presented was a two resistance model which takes care of the heat transfer process on both sides of the interface and uses a variable steam bubble diameter.The injection of supersonic steam jet in subcooled water tank was simulated using the Euler-Euler multiphase flow model of Fluent 6.3 code with the condensation model incorporated. The findings of the computational fluid dynamics（CFD） simulations were compared with the published experimental data and fairly good agreement was observed between the two,thus validating the condensation model.The results of CFD simulations for dimensionless penetration length of steam plume varies from 2.73-7.33,while the condensation heat transfer coefficient varies from 0.75-0.917 MW·（m ^2 ·K）^ -1 for water temperature in the range of 293-343 K.
文摘Silver nanoparticles of mean size 16 nm were synthesized by inert gas condensation （IGC） method. Crystalline structure, morphology and nanoparticles size estimation were conducted by X-ray diffraction （XRD） and transmission electron microscopy （TEM）. Antibacterial activity of these silver nanoparticles as a function of particles concentration against gram-negative bacterium Escherichia coli （E. coli） was carried out in liquid as well as solid growth media. Scanning electron microscopy （SEM） and TEM studies showed that silver nanoparticles after interaction with E.coli have adhered to and penetrated into the bacterial cells. Antibacterial properties of silver nanoparticles are attributed to their total surface area, as a larger surface to volume ratio of nanoparticles provides more efficient means for enhanced antibacterial activity.
文摘The heat transfer of supercritical fluids is a vastly growing field, specifically to find suitable alternatives to replace conventional R134a, which can be beneficial for climate change. Most of the experimental and numerical investigations have been conducted to explore supercritical water, carbon dioxide and R134a as heat transfer working fluids. Hydrofluoroolefin (HFO) and refrigerants blends have been considered the most environment-friendly refrigerants to replace Chlorofluorocarbons (CFCs), Hydrochlorofluoro-carbons (HCFCs) and Hydrofluorocarbons (HFCs). Their main advantage of zero Ozone Depletion Potential (ODP) and comparatively lower Global Warming Potential (GWP) have attracted growing amount of attention to mitigate environmental issues. This work adopts the computational method and takes the environmentally friendly refrigerants to investigate the heat transfer characteristics under widely used shear-stress transport (SST) model. A comprehensive comparison was performed at reduced pressure of 1.10 for supercritical fluids R515A, R1234ze(E) and R134a. The peaks of heat transfer coefficient occurred in the vicinity of pseudo critical temperature for all of these considered fluids;however, R134a resulted in higher heat transfer coefficient, Reynolds number and Prandtl number in comparison with R515A and R1234ze(E). The higher heat transfer coefficient of supercritical fluid R134a is owing to its thermophysical properties and the specific heat plays crucial role in the heat transfer of supercritical fluids. Owing to environmental issues, R515A can be a considerable replacement of R134a. R1234ze(E) is also promising alternative to R134a;however, safety issues should thoroughly concern its mild flammable characteristics.
文摘Fuel reload pattern optimization is essential for attaining maximum fuel burnup for minimization of generation cost while minimizing power peaking factor(PPF).The aim of this work is to carry out detailed assessment of particle swarm optimization(PSO) in the context of fuel reload pattern search. With astronomically large number of possible loading patterns, the main constraints are limiting local power peaking factor, fixed number of assemblies,fixed fuel enrichment, and burnable poison rods. In this work, initial loading pattern of fixed batches of fuel assemblies is optimized by using particle swarm optimization technique employing novel feature of varying inertial weights with the objective function to obtain both flat power profile and cycle k_(eff)>1. For neutronics calculation, PSU-LEOPARD-generated assembly depletiondependent group-constant-based ADD files are used. The assembly data description file generated by PSU-LEOPARD is used as input cross-section library to MCRAC code, which computes normalized power profile of all fuel assemblies of PWR nuclear reactor core. The standard PSO with varying inertial weights is then employed to avoid trapping in local minima. A series of experiments havebeen conducted to obtain near-optimal converged fuelloading pattern of 300 MWe PWR Chashma reactor. The optimized loading pattern is found in good agreement with results found in literature. Hybrid scheme of PSO with simulated annealing has also been implemented and resulted in faster convergence.
