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| 1 | Microstructure Evolution and Mechanical Behavior of Laser Melting Deposited TA15 Alloy at 500℃ under In-Situ Tension in SEM显示文摘TA15 alloy fabricated by laser melting deposition was investigated at 500℃ under tensile deformation. The damage behavior of microstructure was analyzed by the real time observation of the microstructure evolution, microcracks initiation and propagation using in-situ tensile equipment fitted in the SEM chamber. Finally, the mechanism of fracture was discussed. The result showed anisotropic mechanical properties in X-and Z-direction. The existence of columnar β grains and its orientation to the tensile direction were the major factors inducing the anisotropic mechanical properties. As compared to Z-direction specimen, high tensile strength was observed in X-direction specimen due to the resistance in slips propagation provided by the prior-β grain boundaries( β GBs). Accumulation of the cracks at prior β GB caused the shear fracture. In case of Z-direction specimen, parallel orientation of prior β GB and GB α with the tensile direction resulted in a homogeneous deformation. The high reduction of cross section showed the enhanced ductile characteristics at high temperature. | Muhammad Rizwan Junxia Lu Fei Chen Ruxia Chai Rafi Ullah Yuefei Zhang Ze Zhang | 2021 | Acta Metallurgica Sinica(English Letters)2021，34，9： | 2 |
| 2 | Heavy ion ranges from first-principles electron dynamics显示文摘The effects of incident energetic particles,and the modification of materials under irradiation,are governed by the mechanisms of energy losses of ions in matter.The complex processes affecting projectiles spanning many orders of magnitude in energy depend on both ion and electron interactions.Developing multi-scale modeling methods that correctly capture the relevant processes is crucial for predicting radiation effects in diverse conditions.In this work,we obtain channeling ion ranges for tungsten,a prototypical heavy ion,by explicitly simulating ion trajectories with a method that takes into account both the nuclear and the electronic stopping power.The electronic stopping power of self-ion irradiated tungsten is obtained from first-principles timedependent density functional theory(TDDFT).Although the TDDFT calculations predict a lower stopping power than SRIM by a factor of three,our result shows very good agreement in a direct comparison with ion range experiments.These results demonstrate the validity of the TDDFT method for determining electronic energy losses of heavy projectiles,and in turn its viability for the study of radiation damage. | Andrea E.Sand Rafi Ullah Alfredo A.Correa | 2019 | npj Computational Materials2019，，1： | 0 |
| 3 | Secure Transmission of Compressed Medical Image Sequences on Communication Networks Using Motion Vector Watermarking显示文摘Medical imaging plays a key role within modern hospital management systems for diagnostic purposes.Compression methodologies are extensively employed to mitigate storage demands and enhance transmission speed,all while upholding image quality.Moreover,an increasing number of hospitals are embracing cloud computing for patient data storage,necessitating meticulous scrutiny of server security and privacy protocols.Nevertheless,considering the widespread availability of multimedia tools,the preservation of digital data integrity surpasses the significance of compression alone.In response to this concern,we propose a secure storage and transmission solution for compressed medical image sequences,such as ultrasound images,utilizing a motion vector watermarking scheme.The watermark is generated employing an error-correcting code known as Bose-Chaudhuri-Hocquenghem(BCH)and is subsequently embedded into the compressed sequence via block-based motion vectors.In the process of watermark embedding,motion vectors are selected based on their magnitude and phase angle.When embedding watermarks,no specific spatial area,such as a region of interest(ROI),is used in the images.The embedding of watermark bits is dependent on motion vectors.Although reversible watermarking allows the restoration of the original image sequences,we use the irreversible watermarking method.The reason for this is that the use of reversible watermarks may impede the claims of ownership and legal rights.The restoration of original data or images may call into question ownership or other legal claims.The peak signal-to-noise ratio(PSNR)and structural similarity index(SSIM)serve as metrics for evaluating the watermarked image quality.Across all images,the PSNR value exceeds 46 dB,and the SSIM value exceeds 0.92.Experimental results substantiate the efficacy of the proposed technique in preserving data integrity. | Rafi Ullah Mohd Hilmi bin Hasan Sultan Daud Khan Mussadiq Abdul Rahim | 2024 | Computers, Materials & Continua2024，78，3： | 0 |
| 4 | Robust Counting in Overcrowded Scenes Using Batch-Free Normalized Deep ConvNet显示文摘The analysis of overcrowded areas is essential for flow monitoring,assembly control,and security.Crowd counting’s primary goal is to calculate the population in a given region,which requires real-time analysis of congested scenes for prompt reactionary actions.The crowd is always unexpected,and the benchmarked available datasets have a lot of variation,which limits the trained models’performance on unseen test data.In this paper,we proposed an end-to-end deep neural network that takes an input image and generates a density map of a crowd scene.The proposed model consists of encoder and decoder networks comprising batch-free normalization layers known as evolving normalization(EvoNorm).This allows our network to be generalized for unseen data because EvoNorm is not using statistics from the training samples.The decoder network uses dilated 2D convolutional layers to provide large receptive fields and fewer parameters,which enables real-time processing and solves the density drift problem due to its large receptive field.Five benchmark datasets are used in this study to assess the proposed model,resulting in the conclusion that it outperforms conventional models. | Sana Zahir Rafi Ullah Khan Mohib Ullah Muhammad Ishaq Naqqash Dilshad Amin Ullah Mi Young Lee | 2023 | Computer Systems Science & Engineering2023，46，9： | 0 |
| 5 | Climatic Changes and Their Effect on Wildlife of District Dir Lower, Khyber Pakhtunkhwa, Pakistan显示文摘Climatic changes and their impact are increasingly evident in Pakistan,especially in the mountainous regions. Mountain ecosystems are consideredto be sensitive indicators of global warming;even slight variationsin temperature can lead to significant shifts in local climate, which can,in turn, drastically affect the natural environment, subsequently alteringpeople’s lifestyle and wildlife habitats. The targeted area for the presentresearch was Lower Dir District, Pakistan. The study gathered the requiredinformation from primary and secondary sources. Secondary dataon temperature and precipitation were obtained from various sources,i.e., local CBO, including WWF Pakistan. Based on information gatheredon climate change and wildlife, a detailed questionnaire was designed.Results showed that no regular pattern of the increase was found in temperaturefrom 2010 to 2018;the same was noticed in the rainfall decreasepattern. Results also showed that the leading causes behind climaticchanges are an increase in greenhouse gases due to pollution by industries,vehicles, crushing plants, deforestation, and some natural phenomenasuch as floods. The study showed that more than 80% of the respondentsagreed that climatic effects have a significant impact on wildlife, i.e.,the existence of wildlife falls in danger due to climatic changes as it maylead to habitat change, making it difficult for the survival and adaptationof the wildlife. Hence, in consequence, it leads to migration, low growthrate, an increase in morbidity and mortality rate, and finally leading to theextinction of the species or population. It is concluded from the study thatpeople are severely noticing the climatic change and its leading causesare greenhouse gases and deforestation. To control climatic changes andwildlife extinction, we need an appropriate policy for forest conservation,wildlife conservation, prevent hunting, industrial pollution control, vehiclepollution control, increase in plantation, awareness of policy for thecontrol of climatic changes, etc. | Asad Ullah Sayyed Iftekhar Ahmad Rafi Ullah Atta Ullah Khan Sikandar Khan Waheed Ullah Abdul Waris | 2020 | Journal of Atmospheric Science Research2020，3，4： | 0 |
| 6 | Distribution pattern and ecological determinants of an invasive plant Parthenium hysterophorus L., in Malakand division of Pakistan显示文摘After habitat loss,drastic effects of biological invasion caused by alien invasive species to the native biodiversity have been acknowledged worldwide by the agriculturists,ecologists,and governments as it is more overwhelming than pollution,harvest and disease combined.One such example of biological invasion is P.hysterophorus which is considered to be one of the topmost noxious weeds threatening ecosystems diversity in the world,particularly in Pakistan due to its invasive success and generalist nature.Yet no studies have explored the pattern and determinants of plant biodiversity in the Parthenium dominated landscapes.Here we explored the current distribution pattern of this species with relation to environmental variables in the Malakand division of northern Pakistan.Twenty-three sites dominated by P.hysterophorus were identified through a participatory mapping process combined with traditional ecological knowledge and quantitative inventories were made.In total,we found 62 plant species in 55 genera and 32 families,predominately from Asteraceae,Poaceae,and Solanaceae.Ward’s agglomerative clustering procedure showed three well-differentiated,and ecologically meaningful but overlapping vegetation communities.P.hysterophorus was found to be the leading species with an average Importance value ranging from 33.28%to 65.59%.Based on our criteria,surprisingly we found significantly less to be fully(30%)or partially invaded(21%)than the less invaded(47%)plots,indicating the gradual invasive success of the species across the landscape.Canonical Correspondence Analysis(CCA-ordination)has explained 36.9%of the cumulative variance by the first three axes and identified elevation(r=-0.526),slope(r=0.438)and percent sand(r=-0.474)to be the major environmental factors affecting the distribution of P.hysterophorus and associated vegetation.These results suggested that elevation and percent sand negatively affect Parthenium distribution whereas slope has a positive relationship thereby promoting its populations in the region.The generalist nature of this invasive species is likely to have an overall adverse negative effect on the ecosystem functioning and cannot be ignored.Therefore,quick actions should be taken for the management of this noxious weed to avoid economic consequences and potential threats to fragile ecosystems such as that in Malakand division. | Nasrullah KHAN Khudija BIBI Rafi ULLAH | 2020 | Journal of Mountain Science2020，17，7： | 0 |
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