127 results on '"Rafi Ullah Khan"'
Search Results
2. Stimulatory effects of smoke solution and biogas digestate slurry application on photosynthesis, growth, and methylation profiling of solanum tuberosum
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Rafi Ullah Khan, Irfan Ullah, Ghazal Khurshid, Sultan Suboktagin, Abdul Rehman Khan, Iftikhar Zeb, Zahid Ahmad Khan, Muhammad Jamil, Eui Shik Rha, Hayssam M. Ali, and Raza Ahmad
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biostimulants ,biogas digestate slurry ,methylation ,plant-derived smoke ,photosynthesis ,pigments ,Plant ecology ,QK900-989 ,Biology (General) ,QH301-705.5 - Abstract
Biostimulants are obtained from various sources like plants, animals, microorganisms, and industrial by-products as well as waste material. Their utilization in agriculture practices is being increased that is giving positive results. The purpose of the current study was to use plant-derived smoke (SMK) solution and biogas digestate (BGD) slurry as biostimulant to elucidate their impact on potato (Solanum tuberosum) performance. The experiment was conducted in lab as well as field conditions, and SMK and BGD solutions were prepared in varying concentrations such as SMK 1:500, SMK 1:250, BGD 50:50, and BGD 75:25. Foliar applications were performed thrice during experiments and data were collected related to photosynthesis, growth, pigments, and genome-wide methylation profiling. Net photosynthesis rate (A) and water use efficiency (WUE) were found higher in SMK- and BGD-treated lab and field grown plants. Among pigments, BGD-treated plants depicted higher levels of Chl a and Chl b while SMK-treated plants showed higher carotenoid levels. Alongside, enhancement in growth-related parameters like leaf number and dry weight was also observed in both lab- and field-treated plants. Furthermore, DNA methylation profile of SMK- and BGD-treated plants depicted variation compared to control. DNA methylation events increased in all the treatments compared to control except for SMK 1:500. These results indicate that smoke and slurry both act as efficient biostimulants which result in better performance of plants. Biostimulants also affected the genome-wide DNA methylation profile that resultantly might have changed the plant gene expression profiling and played its role in plant responsiveness to these biostimulants. However, there is need to elucidate a possible synergistic effect of SMK and BGD on plant growth along with gene expression profiling.
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- 2024
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3. Guar gum/poly ethylene glycol/graphene oxide environmentally friendly hybrid hydrogels for controlled release of boron micronutrient
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Muhammad Khalid Azeem, Atif Islam, Rafi Ullah Khan, Atta Rasool, Muhammad Anees Ur Rehman Qureshi, Muhammad Rizwan, Raa Khimi Shuib, Abdul Rehman, and Ayesha Sadiqa
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guar gum ,poly (ethylene glycol) ,graphene oxide ,hydrogels ,boron release ,sustained agriculture ,Science - Abstract
The present study was aimed at synthesis of polymeric hydrogels for controlled boron (B) release, as B deficiency is a major factor that decreases crops yield. Thus, graphene oxide incorporated guar gum and poly (ethylene glycol) hydrogels were prepared using the Solution Casting method for boron release. 3-Glycidyloxypropyl trimethoxysilane (GLYMOL) was used as a cross-linker. Characterizations of hydrogels were carried out by Fourier Transform Infrared Spectroscopy (FTIR), Thermo-Gravimetric Analysis and Scanning Electron scope. The FTIR outcomes confirmed the existence of functional groups, bindings and development of hydrogel frameworks from incorporated components. The quantity of GLYMOL directly increased the thermal stability and water retention but decreased the swelling %. The maximum swelling for the hydrogel formulations was observed at pH 7. The addition of GLYMOL changed the diffusion from quasi-Fickcian to non-Fickcian diffusion. The maximum swelling quantities of 3822% and 3342% were exhibited by GPP (control) and GPP-8 in distilled water, respectively. Boron release was determined in distilled water and sandy soil by azomethine-H test using UV-Visible spectrophotometer while 85.11% and 73.65% boron was released from BGPP-16, respectively. In short, water retentive, water holding capacities, swelling performances, biodegradability and swelling/deswelling features would offer an ideal platform for boron release in sustained agricultural applications.
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- 2023
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4. Risk Coupling Assessment of Vehicle Scheduling for Shipyard in a Complicated Road Environment
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Ningfei Wang, Jingbo Yin, and Rafi Ullah Khan
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shipyard ,vehicle scheduling ,risk assessment ,N-K model ,information entropy theory ,Naval architecture. Shipbuilding. Marine engineering ,VM1-989 ,Oceanography ,GC1-1581 - Abstract
Vehicle scheduling at shipyards can involve delays due to numerous risk factors encountered in the complicated shipyard road environment. This paper studies the problems of risk coupling in shipyard vehicle scheduling based on the risk matrix approach, considering the complicated road environment, assessing the degrees of coupling and disorder. Based on safety-engineering theory and comprehensive analysis of the road environment, four key criteria are identified, vehicles, the road environment, the working environment, and humans, including 12 factors and their specific contents. The degree of coupling between various combinations of risk criteria is quantitatively determined utilizing the N-K model. Additionally, the degree of disorder in the risk criteria is assessed based on information entropy theory. The model’s correction coefficients are determined through comparative analysis of experimental data. By integrating the degree of coupling and disorder, delays caused by different combinations of risk criteria in scheduling tasks are computed. The quantitative evaluation model enables accurate appraisal of risk events during shipyard vehicle scheduling. The model provides a valuable managerial tool to analyze delays caused when specific risk criteria are met and to compare these delays to the potential impact on time resulting from adjusting vehicle scheduling plans. This research has significant implications for enhancing vehicle distribution efficiency in shipyards.
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- 2024
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5. Risk Assessment for Autonomous Ships Using an Integrated Machine Learning Approach
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Rafi Ullah Khan, Jingbo Yin, Siqi Wang, and Yingchao Gou
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autonomous ships ,risk assessment ,machine learning ,Bayesian networks ,Engineering machinery, tools, and implements ,TA213-215 - Abstract
The inherent complexities of Artificial Intelligence (AI) and machine learning (ML) technologies expose autonomous ships to a wide range of multifaceted interconnected risks. However, very few studies have aimed at the holistic risk assessment of autonomous ships. To this end, this study employs an expert-opinion-based integrated machine learning approach amalgamating logistic regression and Bayesian network to conduct risk assessment for autonomous ships. The results reveal human factor interactions and operational issues as the prominent accident causation factors. The findings of this study will contribute significantly to the existing literature on autonomous ships and the complexities involved in their operational systems. By identifying critical factors causing accidents and their impact on autonomous ship safety and resilience, stakeholders such as autonomous ship manufacturers, port authorities, shipping companies, and governments can develop more efficient and effective operational and safety systems.
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- 2023
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6. SEAL: Semantically Enriched Authoring in LATEX—A Model for Scientific Discourse
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Imran Ihsan, Mohib Ullah, Rafi Ullah Khan, M. Irfan Uddin, Abdullah Alharbi, and Wael Alosaimi
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Semantic annotation ,semantic authoring ,scientific discourse ,citation Indicators ,citation behaviors ,ontology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Semantic tags can enrich citation graphs by inter-connecting papers with citation reasons. One of the best sources of knowledge to tell the reason for citation is the author himself. Integrating these reasons in an authoring system can help authors to choose a reason while citing. We examined various Human and Automatic authoring systems for integration of citation reasons. However, to the best of our knowledge, no such system exists that facilities authors to integrate the reasons while citing. Same is the case with Cite Packages. This research proposes integration of CCRO:Citations’ Context and Reasons Ontology’s (Ihsan and Qadir, 2019) taxonomic hierarchy of reasons within document. We have developed a CCRO Package to semantically tag citations with reasons and to create an intra-discourse relation between research articles. Furthermore, embedding these structures within RDF Data Store enables the creation of knowledge graphs that become a foundation artifact for the Semantic & Scientific Discourse.
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- 2022
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7. An effective deep learning approach for the classification of Bacteriosis in peach leave
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Muneer Akbar, Mohib Ullah, Babar Shah, Rafi Ullah Khan, Tariq Hussain, Farman Ali, Fayadh Alenezi, Ikram Syed, and Kyung Sup Kwak
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peach leaves ,Bacteriosis detection ,Bacteriosis classification ,deep learning ,convolutional neural network (CNN) ,LWNet ,Plant culture ,SB1-1110 - Abstract
Bacteriosis is one of the most prevalent and deadly infections that affect peach crops globally. Timely detection of Bacteriosis disease is essential for lowering pesticide use and preventing crop loss. It takes time and effort to distinguish and detect Bacteriosis or a short hole in a peach leaf. In this paper, we proposed a novel LightWeight (WLNet) Convolutional Neural Network (CNN) model based on Visual Geometry Group (VGG-19) for detecting and classifying images into Bacteriosis and healthy images. Profound knowledge of the proposed model is utilized to detect Bacteriosis in peach leaf images. First, a dataset is developed which consists of 10000 images: 4500 are Bacteriosis and 5500 are healthy images. Second, images are preprocessed using different steps to prepare them for the identification of Bacteriosis and healthy leaves. These preprocessing steps include image resizing, noise removal, image enhancement, background removal, and augmentation techniques, which enhance the performance of leaves classification and help to achieve a decent result. Finally, the proposed LWNet model is trained for leaf classification. The proposed model is compared with four different CNN models: LeNet, Alexnet, VGG-16, and the simple VGG-19 model. The proposed model obtains an accuracy of 99%, which is higher than LeNet, Alexnet, VGG-16, and the simple VGG-19 model. The achieved results indicate that the proposed model is more effective for the detection of Bacteriosis in peach leaf images, in comparison with the existing models.
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- 2022
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8. Editorial: Polymer blends for drug release systems
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Nafisa Gull, Shahzad Maqsood Khan, Aman Ullah, and Rafi Ullah Khan
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polymers ,blend ,drug release ,crosslinking ,hydrogel ,Technology - Published
- 2022
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9. Development and evaluation of pH-sensitive biodegradable ternary blended hydrogel films (chitosan/guar gum/PVP) for drug delivery application
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Zunaira Huma Ghauri, Atif Islam, Muhammad Abdul Qadir, Nafisa Gull, Bilal Haider, Rafi Ullah Khan, and Tabinda Riaz
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Medicine ,Science - Abstract
Abstract pH responsive hydrogels have gained much attraction in biomedical fields. We have formulated ternary hydrogel films as a new carrier of drug. Polyelectrolyte complex of chitosan/guar gum/polyvinyl pyrrolidone cross-linked via sodium tripolyphosphate was developed by solution casting method. Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis were conducted to examine the interactions between the polymeric chains, surface morphology and thermal stability, respectively. The swelling tests resulted that the swelling was reduced with the increase in the concentration of crosslinker due to the more entangled arrangement and less availability of pores in hydrogels. Ciprofloxacin hydrochloride was used as a model drug and its release in simulated gastric fluid, simulated intestinal fluid and phosphate buffer saline solution was studied. pH responsive behaviour of the hydrogels have subjected these hydrogels for drug release applications.
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- 2021
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10. Dynamic Safety Assessment and Enhancement of Port Operational Infrastructure Systems during the COVID-19 Era
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Siqi Wang, Jingbo Yin, and Rafi Ullah Khan
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Port Infrastructure Network ,COVID-19 ,port disruption ,input–output model ,risk assessment ,Naval architecture. Shipbuilding. Marine engineering ,VM1-989 ,Oceanography ,GC1-1581 - Abstract
Seaports function as lifeline systems in maritime transportation, facilitating critical processes like shipping, distribution, and allied cargo handling. These diverse subsystems constitute the Port Infrastructure System (PIS) and have intricate functional interdependencies. The PIS is vulnerable to several external disruptions, and the impact of COVID-19 is severe and unprecedented in this domain. Therefore, this study proposes a novel general port safety framework to cope with recurring hazards and crisis events like COVID-19 and to augment PIS safety through a multi-state failure system. The PIS is divided into three critical subsystems: shipping, terminal, and distribution infrastructure, thereby capturing its functional interdependency and intricacy. A dynamic input–output model is employed, incorporating the spatial variability and average delay of the disruption, to determine the PIS resilience capacity under the stated disruptions. This study simulates three disruption scenarios and determines the functional failure capacity of the system by generating a functional change curve in Simulink. This study offers viable solutions to port managers, terminal operators, and concerned authorities in the efficient running of intricate interdependent processes and in devising efficient risk control measures to enhance overall PIS resilience and reliability. As part of future studies, given the difficulty in obtaining relevant data and the relatively limited validation of the current model, we aim to improve the accuracy and reliability of our model and enhance its practical applicability to real-world situations with data collected from a real-world case study of a PIS system.
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- 2023
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11. Technical efficiency comparison of container ports in Asian and Middle East region using DEA
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Faluk Shair Mustafa, Rafi Ullah Khan, and Tariq Mustafa
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Port efficiency ,Data Envelopment Analysis ,Comparative efficiency ,Belt and Road Initiative ,Middle East and South Asian region ,East Asian region ,Shipment of goods. Delivery of goods ,HF5761-5780 - Abstract
With the instigation of China Pakistan Economic Corridor (CPEC), the strategic significance of South Asian and Middle Eastern ports have been vitalized. The aim of this study is to compare the technical efficiency of less explored South Asian & Middle Eastern ports with the East Asian ports and determine ways for their efficiency enhancement and management optimization. The cross sectional data for the year 2018 was collected for 15 container ports each of South & Middle Eastern and East Asian region and arranged into input and output variables. The data was analyzed through the DEA-CCR and DEA-BCC model. Results indicate that only one port each from UAE and India among the Middle & South Asian ports were found efficient on CCR model with the number of efficient ports on BCC model increased by 47%. While, in East Asian region two ports of China and one of South Korea were found efficient on CCR model, with 33% increase on BCC model. Lianyungang port was the most prominent among the efficient ports being highly benchmarked. The average efficiency for East Asian region (CCR: 0.524, BCC: 0.901) remained similar to that of South Asian and Middle East Region (CCR: 0.517, BCC: 0.906).
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- 2021
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12. Novel Stimuli-Responsive Pectin-PVP-Functionalized Clay Based Smart Hydrogels for Drug Delivery and Controlled Release Application
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Shabnam Rehmat, Nayab Batool Rizvi, Saba Urooge Khan, Abdul Ghaffar, Atif Islam, Rafi Ullah Khan, Azra Mehmood, Hira Butt, and Muhammad Rizwan
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hydrogel ,pectin ,3-aminopropyl (diethoxy) methylsilane ,polyvinylpyrrolidone ,drug delivery ,pH-responsive ,Technology - Abstract
Stimuli-responsive drug delivery systems are urgently required for injectable site-specific delivery and release of drugs in a controlled manner. For this purpose, we developed novel pH-sensitive, biodegradable, and antimicrobial hydrogels from bio-macromolecule pectin, polyvinylpyrrolidone (PVP), 3-aminopropyl (diethoxy)methyl silane (3-APDEMS), and sepiolite clay via blending and solution casting technique. The purified sepiolite (40 um) was functionalized with 3-APDEMS crosslinker (ex-situ modification) followed by hydrogels fabrication. FTIR and SEM confirmed crosslinked structural integrity and rod-like morphology of hydrogels respectively. The swelling properties of hydrogels could be controlled by varying the concentration of modified clay in pectin/PVP blends. Moreover, the decrease in pH increased the swelling of hydrogels indicating the pH-responsiveness of hydrogels. All hydrogels were degraded after 21 days in phosphate buffer saline pH 7.4 (human blood pH). In-vitro cytotoxicity against 3T3 mouse fibroblast cell line analysis confirmed cytocompatibility of all hydrogels. Ceftriaxone sodium (CTX-S) was selected as a model drug. The release profile of the hydrogel showed 91.82% release in PBS for 2 h in a consistent and controlled manner. The chemical structure of the drug remained intact during and after release confirmed through UV-Visible spectroscopy. Overall, these hydrogels could be used as potential scaffolds for future biomedical applications.
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- 2022
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13. Risk Assessment and Decision Support for Sustainable Traffic Safety in Hong Kong Waters
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Rafi Ullah Khan, Jingbo Yin, Faluk Shair Mustafa, and Hailong Liu
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Accident risk ,potential consequences ,Bayesian networks ,hong kong waters ,maritime traffic safety ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Hong Kong's port is one of the busiest in the world. Such heavy traffic is associated with a high accident rate. The present study uses Bayesian Networks to analyze accident risk in Hong Kong waters using 331 accident reports during the period of 1999-2017. The methodology adopted is comprised of an analysis of present literature and expert judgments for the determination of nodes and states. The calculation of probabilities and conditional probability tables (CPT) were done based solely on the real data in accident reports through parameter estimation. The results indicate that the highest portion of accidents was categorized as “other” with a probability of 0.5174. The majority of such accidents took place in port waters. The second highest category was “collision” with a probability of 0.2256. Both of these accident types were associated with the highest fatality rate-one or two people killed. Poor judgment, negligence and insufficient training were found to be the most influential factors with regard to human actions. The highest rate of injuries was associated with passenger ships. The results offer valuable insights into various accident scenarios which involve setting evidence at different states of consequences and accident types to determine the most prominent contributing factors. Sensitivity analysis was also conducted to recognize the most critical variables. This study should prove useful to decision and policy makers seeking to enhance sustainable safety in maritime traffic operations.
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- 2020
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14. Scheduling management and optimization analysis of intermediate products transfer in a shipyard for cruise ships
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Jiajie Liu, Jingbo Yin, and Rafi Ullah Khan
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Medicine ,Science - Abstract
Shipbuilding is a complex and large-scale operation involving many intermediate products (blocks) and the frequent transfer of blocks among workshops and stockyards. The reasonable use of methods to complete the transfer scheduling of intermediate products is of great importance. In this paper, the blocks and the flat transporters are the research objects. Based on organizing the various logistical processes for blocks and the circulation process in the shipyard, we established a model that takes the task time window and other factors as constraints, and minimizes the sum of delay time and no-load time of flat transporters while satisfying the punctuality of scheduling tasks. Three conclusions are reached: (1)The flat transporter utilization rate is inversely related to the value of the objective function. The smaller the value of the objective function, the more the usage rate of a particular one (2) loading is the biggest obstacle to the overall working time of flat transporters, and a simple optimization model cannot solve this problem; and (3) based on the optimization model, the load efficiency of flat transporters can be improved, and the delivery time can be reduced.
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- 2022
15. Analysis of mixed cattle manure: Kinetics and thermodynamic comparison of pyrolysis and combustion processes
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Muhammad Ashraf, Naveed Ramzan, Rafi Ullah Khan, and Abdullah Khan Durrani
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Dairy manure ,Pyrolysis ,Combustion ,Kinetics ,Isoconversional methods ,Coats-Redfern method ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
The study investigates the non-isothermal thermogravimetric analysis of cattle manure at varied heating rates to compare the kinetic and thermodynamic behaviors of cattle manure in N2 and air atmospheres. The Thermogravimetric (TG) curves indicated that the decomposition of the manure can be divided into three different regions. Exclusive of stage I (dehydration), the activation energy (Ea) values of stage II (devolatilization) for all model-free methods varied between 144 - 270 and 32–227 kJ/mol in pyrolysis and combustion respectively. While in stage III, Ea values varied in ranges of 49–336 kJ/mol and 71–136 kJ/mol for pyrolysis (carbonation) and combustion (char burning), respectively. The overall average Ea for the pyrolysis (≈146 kJ/mol) is higher than the combustion process (≈127 kJ/mol). The variation in the values of frequency factor “A” also indicated the complexity of both processes. Pyrolysis followed overall 2-Diffusion (D2) reaction models, while combustion followed 3-Power law (P3) and reaction Order-1 (O1) in stage II and III respectively. The thermodynamic study was also conducted to evaluate the important parameters, change in Enthalpy change (ΔH), Gibbs free energy (ΔG), and Entropy (ΔS).
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- 2021
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16. Genetic Diversity and Population Structure of the Endangered Ulmusvillosa in Pakistan Revealed by DNA Barcode Markers
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Rafi Ullah Khan, Niaz Ali, Siddiq Ur Rahman, Inayat Ur Rahman, Abeer Hashem, Khalid F. Almutairi, Elsayed Fathi Abd_Allah, Wiwiek Harsonowati, Muazzam Ali Khan, Fazli Rahim, Fahim Ullah Khan, and Noor ul Haq
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genetic variation ,phylogenetics ,conservation ,PCR amplification ,barcode regions ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Ulmus villosa Brandis ex Gamble, an economically and ecologically important forest tree, is native to the western Himalayas of Pakistan. The long pressure imposed by unsustainable utilization and market demands has resulted in the rapid decline of the U. villosa population in the wild. To date, very limited information on the genomic diversity of U. villosa is available and this can tremendously limit our understanding of distribution and future conservation of U. villosa. Therefore, the current study aimed to assess genetic diversity within U. villosa wild populations of the Hazara Division using four barcoding markers (i.e., rbcL, matK XF + 5R, matK 390F + 1326R and trnH-psbA). A total of six high quality sequences were obtained with rbcL, four with matK XF + 5R, four with matK 390F + 1326R, and fourteen with trnH-psbA. The sequenced regions contained insertions and deletions as well as several SNPs across the length of sequences, and PCR-based markers may be developed from these novel SNPs markers. The phylogenetic results supported the polyphyletic origin of the genus Ulmus, and the data indicated that multiple speciation events may have led to the evolution of U. villosa in this region. For deeper understanding of the origin and evolution of U. villosa, sequencing of the complete nuclear and chloroplast genomes will be pivotal. The results herein provide novel insights into the genomic diversity as well as phylogenetic relationships of U. villosa with other species, and may facilitate both in situ and ex situ conservation efforts for this endangered species.
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- 2022
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17. Accident and pollution risk assessment for hazardous cargo in a port environment.
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Rafi Ullah Khan, Jingbo Yin, and Faluk Shair Mustafa
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Medicine ,Science - Abstract
The catastrophic environmental, life and monetary losses concomitant to the hazardous cargo accidents have remained a matter of critical concern for the maritime transportation officials. The factors that instigate these accidents while dealing with hazardous cargo in a port environment requires rigorous analysis and evaluation, which still remains in its infancy. In accord to these prevailing issues, this study focusses on the assessment of multifactor risks associated with the dealing of hazardous cargos inside a port. The methodology adopted is the amalgamation of expert judgment and literature review for the identification of factors and developing their causal relationship, while Bayesian Network (BN) for the inference, which was based on 348 past accident reports from the year 1990 to 2018. The results indicate that under normal circumstances, the probability of an accident with considerable consequences is 59.8, where human and management were found to be the highest contributing factors. Setting evidence at the environment and pollution accident to occur, the incidence probability of the "management" is raised by 7.06%. A sensitivity analysis was conducted to determine the most critical factors for the hazardous cargo accident. This study reveals that in order to evade the hazardous cargo accidents and curtail severity of the consequences, the port authorities, concerned government departments and other related institutions should pay specific attention to the qualification, training and attitude of the involved workforce. Moreover, the development and implementation of stringent safety protocols was also revealed to have critical prominence. This study holds practical vitality for enhancing safety and mitigating risks associated to hazardous cargo dealing in a port.
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- 2021
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18. Integrated Optimization Strategy for Sustainable Shared Designated Driver Ferry Vehicle Scheduling
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Siqi Wang, Jingbo Yin, and Rafi Ullah Khan
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Transportation engineering ,TA1001-1280 ,Transportation and communications ,HE1-9990 - Abstract
The focus of this study is on optimizing the schedule adjustment scheme of shared designated driver ferry vehicles to obtain a sustainable and energy-efficient system to pick up and drop off designated drivers to serve drunk customers. A two-stage matching model for driver and customer supply and demand matching and driver ferry vehicle dispatching is designed in order to optimize the total distance travelled and minimize the generalized deviation costs. A maximum residual time adjustment algorithm is designed to reduce the logarithm of new interference demand, and a tabu search algorithm is used to solve the schedule adjustment scheme for ferry vehicles. The validity of the model and the algorithm is verified by a multiperiod example constructed in the Solomon test question bank. The result of numerical experiments shows that the proposed model and algorithm can solve the disruption adjustment scheduling strategy of shared designated driver ferry vehicles. The integrated optimization strategy can effectively improve the utilization rate and the operation efficiency of the shared driver ferry vehicles to reduce operation cost and energy consumption.
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- 2021
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19. Determining Role of Human Factors in Maritime Transportation Accidents by Fuzzy Fault Tree Analysis (FFTA)
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Ali Zaib, Jingbo Yin, and Rafi Ullah Khan
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maritime transportation ,risk analysis ,accident model ,human factors ,fuzzy fault tree analysis ,Naval architecture. Shipbuilding. Marine engineering ,VM1-989 ,Oceanography ,GC1-1581 - Abstract
Safety has been a primary concern in every industry. It includes system, personnel, environmental safety, etc. Maritime transportation safety is of the utmost importance because a lot of economic and environmental damage has been caused by ship-related accidents. The majority of these accidents have resulted from human factors. For the analysis of accidents and future safety, various accident models have been created. In this study, human-based errors are analyzed and quantified by using the fuzzy fault tree analysis, which helps calculate the failure probability of the causes. A real-life case of a chemical tanker Key Bora was studied and analyzed, which happened on 28 March 2020, at Kyleakin Pier, Isle of Skye, Scotland. The ship’s hull was seriously damaged and was flooded. According to the analysis, two main human factors that contributed the most to the occurrence of this accident were found. These incidents can be avoided by ensuring proper measures are followed, and the results can be used as guidelines for future marine accident investigations and safety.
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- 2022
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20. Quaternized Diaminobutane/Poly(vinyl alcohol) Cross-Linked Membranes for Acid Recovery via Diffusion Dialysis
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Muhammad Adnan Ashraf, Atif Islam, Muhammad Arif Butt, Hafiz Abdul Mannan, Rafi Ullah Khan, Kashif Kamran, Shahid Bashir, Javed Iqbal, Ahmed A. Al-Ghamdi, and Abdullah G. Al-Sehemi
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diffusion dialysis ,PVA ,TEOS cross-linked ,acid recovery ,anion exchange membrane ,Chemical technology ,TP1-1185 ,Chemical engineering ,TP155-156 - Abstract
Diffusion dialysis (DD) using anion exchange membranes (AEM) is an effective process for acid recovery and requires the preparation of suitable materials for AEMs, characterized by unique ions transport properties. In this work, novel AEMs composed of quaternized diaminobutane (QDAB) and poly(vinyl alcohol) (PVA) were cross-linked by tetraethoxysilane (TEOS) via the sol–gel process. The prepared AEMs were systematically characterized by Fourier-transform infrared (FTIR) spectroscopy, ion-exchange capacity (IEC) analysis, thermo gravimetric analysis (TGA), water uptake, linear expansion ratio (LER), and mechanical strength determination, scanning electron microscopy (SEM), and DD performance analysis for acid recovery using a hydrochloric acid/iron chloride (HCl/FeCl2) aqueous mixture and varying the QDAB content. The prepared AEMs exhibited IEC values between 0.86 and 1.46 mmol/g, water uptake values within 71.3 and 47.8%, moderate thermal stability, tensile strength values in the range of 26.1 to 41.7 MPa, and elongation from 68.2 to 204.6%. The dialysis coefficient values were between 0.0186 and 0.0295 m/h, whereas the separation factors range was 24.7–44.1 at 25 °C. The prepared membranes have great potential for acid recovery via diffusion dialysis.
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- 2021
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21. Effect of Varying Amount of Polyethylene Glycol (PEG-600) and 3-Aminopropyltriethoxysilane on the Properties of Chitosan based Reverse Osmosis Membranes
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Anum Kayani, Muhammad Asim Raza, Arsalan Raza, Tajamal Hussain, Muhammad Sarfraz Akram, Aneela Sabir, Atif Islam, Bilal Haider, Rafi Ullah Khan, and Sang Hyun Park
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films ,hydrophilicity ,surface morphology ,cross-linking ,permeate flux ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Chitosan and polyethylene glycol (PEG-600) membranes were synthesized and crosslinked with 3-aminopropyltriethoxysilane (APTES). The main purpose of this research work is to synthesize RO membranes which can be used to provide desalinated water for drinking, industrial and agricultural purposes. Hydrogen bonding between chitosan and PEG was confirmed by displacement of the hydroxyl absorption peak at 3237 cm−1 in pure chitosan to lower values in crosslinked membranes by using FTIR. Dynamic mechanical analysis revealed that PEG lowers Tg of the modified membranes vs. pure chitosan from 128.5 °C in control to 120 °C in CS-PEG5. SEM results highlighted porous and anisotropic structure of crosslinked membranes. As the amount of PEG was increased, hydrophilicity of membranes was increased and water absorption increased up to a maximum of 67.34%. Permeation data showed that flux and salt rejection value of the modified membranes was increased up to a maximum of 80% and 40.4%, respectively. Modified films have antibacterial properties against Escherichia coli as compared to control membranes.
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- 2021
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22. A Review of Biodegradable Natural Polymer-Based Nanoparticles for Drug Delivery Applications
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Humaira Idrees, Syed Zohaib Javaid Zaidi, Aneela Sabir, Rafi Ullah Khan, Xunli Zhang, and Sammer-ul Hassan
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polymers ,biodegradable ,nanoparticles ,drug delivery ,pharmaceutical ,Chemistry ,QD1-999 - Abstract
Biodegradable natural polymers have been investigated extensively as the best choice for encapsulation and delivery of drugs. The research has attracted remarkable attention in the pharmaceutical industry. The shortcomings of conventional dosage systems, along with modified and targeted drug delivery methods, are addressed by using polymers with improved bioavailability, biocompatibility, and lower toxicity. Therefore, nanomedicines are now considered to be an innovative type of medication. This review critically examines the use of natural biodegradable polymers and their drug delivery systems for local or targeted and controlled/sustained drug release against fatal diseases.
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- 2020
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23. Novel Maleic Acid, Crosslinked, Nanofibrous Chitosan/Poly (Vinylpyrrolidone) Membranes for Reverse Osmosis Desalination
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Israr Ali, Muhammad Asim Raza, Rashid Mehmood, Atif Islam, Aneela Sabir, Nafisa Gull, Bilal Haider, Sang Hyun Park, and Rafi Ullah Khan
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electrospinning ,reverse osmosis ,desalination ,permeation flux ,salt rejection ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Fresh and clean water is consistently depleting and becoming a serious problem with rapid increases in population, so seawater desalination technology has captured global attention. For an efficient desalination process, this work proposes a novel, nanofibrous, thin-film composite membrane (NF-TFC) based on the deposition of the nanofibrous active layer of a blend of chitosan (CS) and poly (vinylpyrrolidone) (PVP) crosslinked with maleic acid on a 3-triethoxysilylpropylamine functionalized cellulose acetate substrate. FTIR analysis demonstrated the development of chemical and physical interactions and confirmed the incorporation of functional groups present in the NF-TFC. Scanning electron microscopy (SEM) micrographs depict the fibrous structure of the active layers. The reverse osmosis (RO) desalination characteristics of NF-TFC membranes are elevated by increasing the concentration of the crosslinker in a CS/PVP blend. Cellulose acetate (CA)-S4 attained an optimal salt rejection of 98.3% and permeation flux of 42.9 L/m2h, suggesting that the NF-TFC membranes could be favorable for seawater desalination.
- Published
- 2020
- Full Text
- View/download PDF
24. Mechanism of Fatigue Crack Growth in Biomedical Alloy Ti-27Nb
- Author
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Muhammad Amjad, Saeed Badshah, Amer Farhan Rafique, Muhammad Adil Khattak, Rafi Ullah Khan, and Wail Ismail Abdullah Harasani
- Subjects
Titanium alloys ,microstructure ,fracture toughness ,fatigue crack growth behavior ,simulated body fluid ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
Implants are widely used in the human body for the replacement of affected bones. Fatigue failure is one of the serious concerns for implants. Therefore, understanding of the underlying mechanism leading to fatigue failure is important for the longevity of biomaterial implants. In this paper, the fracture toughness and fatigue crack growth of titanium alloy biomaterial Ti-27Nb has been experimentally investigated. The Ti-27Nb material is tested for fatigue crack growth in different environmental conditions representing the ambient and in vitro environments for 504 hours and 816 hours, respectively. Fractography of the tested specimen is conducted using Scanning Electron Microscope (SEM). The results of the fatigue crack growth propagation of the ambient and in vitro samples are similar in the Paris crack growth region. However, in the threshold region, the crack growth rate is higher for the Simulated Body Fluid (SBF) treated specimen. The fracture surface morphology of in vitro samples shows brittle fracture as compared to ambient specimens with significant plasticity and striations marks. It is proposed that a similar investigation may be conducted with specimens treated in SBF for prolonged periods to further ascertain the findings of this study.
- Published
- 2020
- Full Text
- View/download PDF
25. Characterization of PTFE Film on 316L Stainless Steel Deposited through Spin Coating and Its Anticorrosion Performance in Multi Acidic Mediums
- Author
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Waseem Akram, Amer Farhan Rafique, Nabeel Maqsood, Afzal Khan, Saeed Badshah, and Rafi Ullah Khan
- Subjects
polytetrafluoroethylene ,316l stainless steel ,corrosion performance ,coating ,microstructure morphology ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
Polytetrafluoroethylene (PTFE) was coated on 316L stainless steel (SS) substrate through a spin coating technique to enhance its corrosion resistance properties in hydrochloric acid (HCl) and nitric acid (HNO3) medium. Scanning electron microscopy (SEM) revealed the morphology of the coated and uncoated substrates and showed a uniform and crack-free PTFE coating on 316L SS substrate, while a damaged surface with thick corrosive layers was observed after the electrochemical test on the uncoated sample. However, an increased concentration of HCl and HNO3 slightly affected the surface morphology by covering the corrosive pits. An atomic force microscope (AFM) showed that the average surface roughness on 316L SS and PTFE coating was 26.3 nm and 24.1 nm, respectively. Energy dispersive X-ray spectroscopy (EDS) was used for the compositional analysis, which confirmed the presence of PTFE coating. The micro Vickers hardness test was used to estimate the hardness of 316L SS and PTFE-coated substrate, while the scratch test was used to study the adhesion properties of PTFE coating on 316L SS. The anticorrosion measurements of 316L SS and PTFE-coated substrates were made in various HCl and HNO3 solutions by using the electrochemical corrosion test. A comparison of the corrosion performance of PTFE-coated substrate with that of bare 316L SS substrate in HCl medium showed a protection efficiency (PE) of 96.7%, and in the case of HNO3 medium, the PE was 99.02%, by slightly shifting the corrosion potential of the coated sample towards the anodic direction.
- Published
- 2020
- Full Text
- View/download PDF
26. Modelingof Acetylene Pyrolysis under Steel Vacuum Carburizing Conditions in a Tubular Flow Reactor
- Author
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Rainer Reimert, Frank Graf, Siegfried Bajohr, and Rafi Ullah Khan
- Subjects
Acetylene ,Pyrolysis ,Modeling ,Simulation ,Carburizing ,Organic chemistry ,QD241-441 - Abstract
In the present work, the pyrolysis of acetylene was studied under steel vacuumcarburizing conditions in a tubular flow reactor. The pyrolysis temperature ranged from650 °C to 1050 °C. The partial pressure of acetylene in the feed mixture was 10 and 20mbar, respectively, while the rest of the mixture consisted of nitrogen. The total pressureof the mixture was 1.6 bar. A kinetic mechanism which consists of seven species andnine reactions has been used in the commercial computational fluid dynamics (CFD)software Fluent. The species transport and reaction model of Fluent was used in thesimulations. A comparison of simulated and experimental results is presented in thispaper.
- Published
- 2007
- Full Text
- View/download PDF
27. Sustainable and environment Friendlier carrageenan-based pH-responsive hydrogels: swelling behavior and controlled release of fertilizers
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Muhammad Khalid Azeem, Atif Islam, Muhammad Rizwan, Atta Rasool, Nafisa Gul, Rafi Ullah Khan, Shahzad Maqsood Khan, and Tahir Rasheed
- Subjects
Colloid and Surface Chemistry ,Polymers and Plastics ,Materials Chemistry ,Physical and Theoretical Chemistry - Published
- 2023
28. Robust Counting in Overcrowded Scenes Using Batch-Free Normalized Deep ConvNet
- Author
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Sana Zahir, Rafi Ullah Khan, Mohib Ullah, Muhammad Ishaq, Naqqash Dilshad, Amin Ullah, and Mi Young Lee
- Subjects
General Computer Science ,Control and Systems Engineering ,Theoretical Computer Science - Published
- 2023
29. Understanding consumer adoption of mobile payment in Pakistan
- Author
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Salman Khan, Safeer Ullah Khan, Ikram Ullah Khan, Sher Zaman Khan, and Rafi Ullah Khan
- Abstract
Purpose This study aims to explore the consumers’ choices of mobile payments (m-payments) using a comprehensive unified model. The financial technology for digital m-payment has been increasingly introduced in the market, yet their acceptance has remained low. Design/methodology/approach This study uses the unified theory of acceptance and use of technology (UTAUT) with additional constructs of social influence, trust, anxiety, personal innovativeness and grievance redressal (GR). Structural equation modeling is used to evaluate the predictive model of attitudes toward m-payment. Individuals’ responses to questions regarding their attitude and intention to accept m-payment were gathered and examined through the lens of extended UTAUT model. Findings While the model supports TAM classical role, empirical examination of the model revealed that users’ attitudes and intentions are influenced by trust, personal innovativeness and social influence. Moreover, intention to use and GR are significant positive predictors of m-payment usage behavior. Originality/value M-payment provides customers with new digital payment platforms while providing businesses and marketing agents with more alternatives for online marketing. However, there is not much reported about m-payment adoption in Pakistan. This research introduces and evaluates new constructs that were not included in the original model. In Pakistan, to the best of the authors’ knowledge, this is a first of its kind of research which is purely based on the customers’ perspective of m-payment adoption.
- Published
- 2023
30. Tanz-Indicator: A Novel Framework for Detection of Perso-Arabic-Scripted Urdu Sarcastic Opinions
- Author
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Shabana Gul, Rafi Ullah Khan, Mohib Ullah, Roman Aftab, Abdul Waheed, and Tsu-Yang Wu
- Subjects
Article Subject ,Computer Networks and Communications ,Electrical and Electronic Engineering ,Information Systems - Abstract
Automatic sarcasm detection in textual data is a crucial task in sentiment analysis. This problem is complex because sarcastic comments usually carry the opposite meaning and are context-driven. The issue of sarcasm detection in comments written in Perso-Arabic-scripted Urdu text is even more challenging due to limited online linguistic resources. In this research, we proposed Tanz-Indicator, a lexicon-based framework to detect sarcasm in the user comments posted in Perso-Arabic Urdu language. We use a lexicon of over 3000 sarcastic tweets and 100 sarcastic features for experimentation. We also train two machine learning models with the same data to compare the performance of the lexicon-based model and machine learning-based model. The results show that the lexicon-based model correctly identified 48.5% sarcastic and 23.5% nonsarcastic tweets with the recall of 69.6% and 87.9% precision. The recall rate of Naïve Bayes and SVM-based machine learning models was 20.1% and 24.4%, respectively, with an overall accuracy of 65.2% and 60.1%, respectively.
- Published
- 2022
31. A Survey on Performance Evaluation Mechanisms for Privacy-Aware Web Search Schemes
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Rafi Ullah Khan, Mohib Ullah, Bushra Shafi, and Imran Ihsan
- Abstract
Due to the exponential growth of information on the internet, web search engines (WSEs) have become indispensable for effectively retrieving information. Web search engines store the users' profiles to provide the most relevant results. However, the user profiles may contain sensitive information, including the user's age, gender, health condition, personal interests, religious or political affiliation, and others. However, this raises serious concerns for the user's privacy since a user's identity may get exposed and misused by third parties. Researchers have proposed several techniques to address the issue of privacy infringement while using WSE, such as anonymizing networks, profile obfuscation, and private information retrieval (PIR) protocols. In this chapter, the authors give a brief survey of the privacy attacks and evaluation models used to evaluate the performance of private web search techniques.
- Published
- 2023
32. SDSCCM
- Author
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Danish Javeed, Tianhan Gao, Muhammad Shahid Saeed, Rafi Ullah Khan, and Zeeshan Jamil
- Abstract
The current century has witnessed a prodigious expansion in scientific innovations contributing toward the betterment of humanity. The astonishing advancements in digital communications have facilitated various spheres of our lifestyle including the manufacturing sector. A plethora of cutting-edge technologies are rubbing shoulders to revolutionize manufacturing trends. Distributed system communications introduce a new concept of digital collaboration among a diversified range of scattered communication nodes. The individual resources of multiple nodes are intelligently integrated to formulate an aggregated impact that yields phenomenal productivity. The smart connectivity among various heterogeneous nodes may familiarize the network with an extended variety of potential security threats. The literature environs a bulk of security solutions proposed to overcome these challenges. This research study provides a comprehensive elaboration of these security threats along with the security practices designed to encounter such activities.
- Published
- 2023
33. Web Search Privacy Evaluation Metrics
- Author
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Rafi Ullah Khan, Mohib Ullah, and Bushra Shafi
- Abstract
Privacy quantification methods are used to quantify the knowledge the adverse search engine has obtained with and without privacy protection mechanisms. Thus, these methods calculate privacy exposure. Private web search techniques are based on many methods (e.g., proxy service, query modification, query exchange, and others). This variety of techniques prompted the researchers to evaluate their work differently. This section introduces the metrics used to evaluate user privacy (protection). Moreover, this section also introduces the metrics used to evaluate the performance of privacy attacks and theoretical evaluation approaches.
- Published
- 2023
34. Angiogenic potential and wound healing efficacy of chitosan derived hydrogels at varied concentrations of APTES in chick and mouse models
- Author
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Chaman Ara, Sehrish Jabeen, Gul Afshan, Ariba Farooq, Muhammad Sarfraz Akram, null Asmatullah, Atif Islam, Shumaila Ziafat, Bushra Nawaz, and Rafi Ullah Khan
- Subjects
Chitosan ,Mice ,Wound Healing ,Propylamines ,Structural Biology ,Polyvinyl Alcohol ,Animals ,Hydrogels ,Chick Embryo ,General Medicine ,Silanes ,Molecular Biology ,Biochemistry - Abstract
Chitosan (Cs) based biomaterials seem to be indispensable for neovasculogenesis and angiogenesis that ensure accelerated wound healing. Cs/poly (vinyl alcohol) (PVA) bio-constructs were cross-linked and investigated with varying concentrations of aminopropyltriethoxysilane (APTES). This study comprised of three phases: fabrication of hydrogels, characterization, assessment of angiogenic potential along with toxico-pathological effects, wound healing efficacy in chick and mice, respectively. The hydrogels were characterized by FTIR, SEM and TGA and the swelling response was examined in different solvents. The hydrogels swelling ratio was decreased with increasing amount of APTES, showed the highest swelling at acidic and basic pH while low swelling at neutral pH. Chorioallantoic membranes (CAM) assay was performed to study in-vivo angiogenesis, toxicological, morphological, biochemical and histological analyses in developing chicks. The results showed remarkably improved angiogenesis with little deviations in morphological, histological features and liver enzymes of chick embryos at higher concentrations of APTES. Besides, full thickness wounds were excised on mice dorsolateral skin to assess the wound healing. The rate of wound size reduction was significantly higher after topical application of hydrogels with elevated levels of crosslinker. Hence, the hydrogels showed enhanced angiogenesis, accelerated wound healing with little or no observable in-vivo toxicity.
- Published
- 2022
35. Profile Aware ObScure Logging (PaOSLo): A Web Search Privacy-Preserving Protocol to Mitigate Digital Traces
- Author
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Mohib Ullah, Rafi Ullah Khan, Irfan Ullah Khan, Nida Aslam, Sumayh S. Aljameel, Muhammad Inam Ul Haq, and Muhammad Arshad Islam
- Subjects
Article Subject ,Computer Networks and Communications ,Information Systems - Abstract
Web search querying is an inevitable activity of any Internet user. The web search engine (WSE) is the easiest way to search and retrieve data from the Internet. The WSE stores the user’s search queries to retrieve the personalized search result in a form of query log. A user often leaves digital traces and sensitive information in the query log. WSE is known to sell the query log to a third party to generate revenue. However, the release of the query log can compromise the security and privacy of a user. In this work, we propose a Profile Aware ObScure Logging (PaOSLo) Web search privacy-preserving protocol that mitigates the digital traces a user leaves in Web searching. PaOSLo systematically groups users based on profile similarity. The primary objective of this work is to evaluate the impact of the systematic group compared to random grouping. We first computed the similarity between the users’ profiles and then clustered them using the K-mean algorithm to group the users systematically. Unlikability and indistinguishability are the two dimensions in which we have measured the privacy of a user. To compute the impact of systematic grouping on a user’s privacy, we have experimented with and compared the performance of PaOSLo with modern distributed protocols like OSLo and UUP(e). Results show that, at the top degree of the ODP hierarchy, PaOSLo preserved 10% and 3% better profile privacy than the modern distributed protocols mentioned above. In addition, the PaOSLo has less profile exposure for any group size and at each degree of the ODP hierarchy.
- Published
- 2022
36. Fabrication and dialysis performance of functionalized multiwall carbon nanotubes integrated cellulose acetate/poly(vinylpyrrolidone) membranes
- Author
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Atif Islam, Muhammad Arif Butt, Tajamal Hussain, Shahid Bashir, Rafi Ullah Khan, Muhammad Adnan Ashraf, and Javed Iqbal
- Subjects
Nanotubes, Carbon ,Chemistry ,Membrane structure ,Povidone ,Membranes, Artificial ,General Medicine ,Carbon nanotube ,Biochemistry ,Cellulose acetate ,law.invention ,Contact angle ,chemistry.chemical_compound ,Membrane ,Chemical engineering ,Renal Dialysis ,Structural Biology ,law ,Creatinine ,Urea ,Thermal stability ,Cellulose ,Glass transition ,Hydrophobic and Hydrophilic Interactions ,Molecular Biology - Abstract
Mixed matrix membranes (MMMs) of cellulose acetate/poly(vinylpyrrolidone) (CA/PVP) infused with acid functionalized multiwall carbon nanotubes (f-MWCNTs) were fabricated by an immersion phase separation technique for hemodialysis application. Membranes were characterized using FTIR, water uptake, contact angle, TGA, DMA and SEM analysis. The FTIR was used to confirm the bonding interaction between CA/PVP membrane matrix and f-MWCNTs. Upon addition of f-MWCNTs, TGA thermograms and glass transition temperature indicated improved thermal stability of MMMs. The surface morphological analysis demonstrated revealed uniform distribution of f-MWCNTs and asymmetric membrane structure. The water uptake and contact angle confirmed that hydrophilicity was increased after incorporation of f-MWCNTs. The membranes demonstrated enhancement in water permeate flux, bovine serum albumin (BSA) rejection with the infusion of f-MWCNTs; whereas BSA based anti-fouling analysis using flux recovery ratio test shown up to 8.4% improvement. The urea and creatinine clearance performance of MMMs were evaluated by dialysis experiment. It has been found that f-MWCNTs integrated membranes demonstrated the higher urea and creatinine clearance with increase of 12.6% and 10.5% in comparison to the neat CA/PVP membrane. Thus, the prepared CA/PVP membranes embedded with f-MWCNTs can be employed for wide range of dialysis applications.
- Published
- 2021
37. Cephradine drug release using electrospun chitosan nanofibers incorporated with halloysite nanoclay
- Author
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Atta Rasool, Sehrish Jabeen, Mahwish Naz, Muhammad Rizwan, Abdul Ghaffar, Samar Z. Alshawwa, Atif Islam, Munawar Iqbal, Rafi Ullah Khan, and Nafisa Gull
- Subjects
Chitosan ,chemistry.chemical_compound ,Materials science ,Chemical engineering ,chemistry ,Electrospun nanofibers ,Nanofiber ,engineering ,Drug release ,Physical and Theoretical Chemistry ,engineering.material ,Cephradine ,Halloysite - Abstract
The chitosan/polyvinyl alcohol/halloysite nanoclay (CS/PVA/HNC) loaded with cephradine drug electrospun nanofibers (NFs) were fabricated and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) techniques. FTIR analysis confirmed the hydrogen bonding between the polymer chain and the developed siloxane linkages. SEM analysis revealed the formation of uniform NFs having beads free and smooth surface with an average diameter in 50–200 nm range. The thermal stability of the NFs was increased by increasing the HNC concentration. The antimicrobial activity was examined against Escherichia coli and staphylococcus strains and the NFs revealed auspicious antimicrobial potential. The drug release was studied at pH 7.4 (in PBS) at 37 °C. The drug release analysis showed that 90% of the drug was released from NFs in 2 h and 40 min. Hence, the prepared NFs could be used as a potential drug carrier and release in a control manner for biomedical application.
- Published
- 2021
38. Sodium alginate blended membrane with polyurethane: Desalination performance and antimicrobial activity evaluation
- Author
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Misbah Sultan, Atif Islam, Aneela Sabir, Saba Urooge Khan, Munawar Iqbal, Muhammad Naeem Ahmed, Rafi Ullah Khan, Sadaf Hafeez, Ismat Bibi, and Shahzad Khan
- Subjects
Osmosis ,Alginates ,Polyurethanes ,chemistry.chemical_element ,Salt (chemistry) ,Bacillus ,02 engineering and technology ,Biochemistry ,Desalination ,03 medical and health sciences ,chemistry.chemical_compound ,Anti-Infective Agents ,Structural Biology ,Chlorine ,Thermal stability ,Fourier transform infrared spectroscopy ,Reverse osmosis ,Molecular Biology ,030304 developmental biology ,Polyurethane ,chemistry.chemical_classification ,0303 health sciences ,Osmolar Concentration ,technology, industry, and agriculture ,Membranes, Artificial ,General Medicine ,021001 nanoscience & nanotechnology ,Membrane ,chemistry ,Chemical engineering ,0210 nano-technology ,Gels - Abstract
A series of polymeric membranes were synthesized by blending polyurethane with sodium alginate (0.2, 0.4, 0.6, 0.8 and 1.0%). The structural, morphological and thermal properties of the membranes were examined by FTIR, SEM, AFM and TGA, respectively. Performance evaluation (salt rejection and flux) was assessed through reverse osmosis technique (RO). The FTIR spectra of membranes confirmed extensive hydrogen bonding (3350 cm−1). The SEM and AFM analyses supported a progressively rising surface roughness of blended membranes. The hydrophilicity, crosslinking density and thermal stability of the membranes were improved with an increase in alginate content. The capability of salt (NaCl and MgCl2) rejection was improved with alginate up to 0.8%. In addition, the rejection of divalent ions was better than monovalent ions (94 ± 0.96% for NaCl and 98 ± 0.98% for MgCl2). The blended membranes ascertained an effective chlorine resistivity. The antibacterial activity was also promising, which enhanced with the alginate content in the membrane. The sodium alginate blended membrane with polyurethane proved to be an efficient approach to develop the blended membranes with tunable properties for water desalination.
- Published
- 2021
39. Development and characterization of chitosan and acrylic acid-based novel biodegradable polymeric films for soil conditioning
- Author
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Muhammad Bilal, Rafi Ullah Khan, Nafisa Gull, Abdul Ghaffar, Shahzad Khan, Sehrish Jabeen, Sumayya, Atif Islam, Sadia Sagar Iqbal, and Nazim Hussain
- Subjects
Staphylococcus aureus ,Biodegradable Plastics ,02 engineering and technology ,Biochemistry ,Chitosan ,Soil ,03 medical and health sciences ,chemistry.chemical_compound ,Structural Biology ,medicine ,Thermal stability ,Molecular Biology ,030304 developmental biology ,Acrylic acid ,0303 health sciences ,General Medicine ,Biodegradation ,Silicon Dioxide ,021001 nanoscience & nanotechnology ,Soil conditioner ,Acrylates ,chemistry ,Distilled water ,Triethoxysilane ,Wettability ,Nanoparticles ,Swelling ,medicine.symptom ,0210 nano-technology ,Nuclear chemistry - Abstract
In this study, biodegradable polymeric films (BPFs) based on chitosan and acrylic acid cross-linked with 3-aminopropyl triethoxysilane (APTES) were developed for water retention and soil-conditioning applications in areas sufferings from water scarcity. A series of BPFs were prepared by varying the amount of silica nanoparticles (SiNPs) (0.67% to 2.6%) and a correlation of the optimum amount of SiNPs with thermal stability, morphology, swellability (at various pH), degradability, and anti-microbial activity were deduced. The obtained results showed that the NP 8 (containing 2.51% of SiNPs) exhibited the maximum absorption capacity (1815%) in distilled water, whereas NP6 (including 1.88% of SiNPs) expressed the maximum thermal stability (T50% at 375.61 °C). The microscopic images further strengthen this observation because the maximum number of micro-porous cavities was shown on the surface of NP8. The time-dependent swelling response in distilled water accomplished that hydrophilicity (percentage swelling) of films was enhanced with an increase in the concentration of SiNPs. All BPFs samples exhibited inhibitory response against both gram-positive (for Staphylococcus aureus was 2.9 cm for NP6) and gram-negative (for Escherichia coli was 0.9 cm for NP8) bacteria. The biodegradation test inferred that the degradation of BPFs in soil did not affect the soil fertility as nano-silica is proven as growth-promoting miniatures. It can be concluded that these BPFs may be efficiently employed in the agriculture sector for water retention and as a soil conditioner.
- Published
- 2021
40. Performance Improvement of Glass Fiber/Epoxy Composites Upon Integrating with N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane Functionalized Graphene Oxide
- Author
-
Fahd Jamshaid, Rafi Ullah Khan, and Atif Islam
- Subjects
Thermogravimetric analysis ,Materials science ,Polymers and Plastics ,Glass fiber ,Izod impact strength test ,02 engineering and technology ,Epoxy ,Dynamic mechanical analysis ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Dynamic light scattering ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium ,Fiber ,Composite material ,0210 nano-technology ,Glass transition - Abstract
Surface tuned GO sheets are considered the opportune pothunter for the reinforcement of conventional glass fiber reinforced composites (GFRCs). Herein, we have tried to disseminate the effects of N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane functionalized GO (GO-AEAPTS) and pristine GO sheets on thermo-mechanical properties of epoxy/glass fiber composites. Fourier Transform-infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic light scattering (DLS) and transmission electron microscope (TEM) were used to characterize the GO sheets. Multiscale composites integrated with GO-AEAPTS (1.5 wt%) provided maximum gain in all the studied properties i.e., interlaminar shear strength (ILSS), impact strength and thermal conductivity were improved by ~ 55, ~ 24 and ~ 70%, respectively. Storage modulus and glass transition temperature increased by ~ 44% and 14 °C, over the neat GFRC. In addition, GO-AEAPTS composites exhibited higher coefficient of effectiveness and crosslink density than those of GO counterparts. These property enhancements were credited to the homogeneous distribution of GO sheets, strong interfacial interactions (interfacial covalent interactions and hydrogen bonding) between GO-AEAPTS and epoxy resin as well as good fiber/matrix compatibility. Such multiscale composites with functional properties can outperform conventional counterparts with improved safety and reliability of structures and reduce maintenance costs.
- Published
- 2021
41. Cattle dung conversion to syngas: solar photovoltaic integrated gasification system
- Author
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Muhammad Ashraf, Naveed Ramzan, Mudassar Azam, Adeel Anwar, Rafi Ullah Khan, Abdullah Khan Durrani, and Muhammad Usman Rashid
- Subjects
Renewable Energy, Sustainability and the Environment - Published
- 2022
42. Technical efficiency comparison of container ports in Asian and Middle East region using DEA
- Author
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Rafi Ullah Khan, Tariq Mustafa, and Faluk Shair Mustafa
- Subjects
050210 logistics & transportation ,Comparative efficiency ,South asia ,Middle East ,lcsh:HF5761-5780 ,05 social sciences ,Transportation ,East Asian region ,Management Science and Operations Research ,Port (computer networking) ,Belt and Road Initiative ,East asian region ,Geography ,Data Envelopment Analysis ,Management of Technology and Innovation ,0502 economics and business ,Efficiency comparison ,lcsh:Shipment of goods. Delivery of goods ,East Asia ,Middle East and South Asian region ,Port efficiency ,Business and International Management ,Socioeconomics ,China ,050203 business & management - Abstract
With the instigation of China Pakistan Economic Corridor (CPEC), the strategic significance of South Asian and Middle Eastern ports have been vitalized. The aim of this study is to compare the technical efficiency of less explored South Asian & Middle Eastern ports with the East Asian ports and determine ways for their efficiency enhancement and management optimization. The cross sectional data for the year 2018 was collected for 15 container ports each of South & Middle Eastern and East Asian region and arranged into input and output variables. The data was analyzed through the DEA-CCR and DEA-BCC model. Results indicate that only one port each from UAE and India among the Middle & South Asian ports were found efficient on CCR model with the number of efficient ports on BCC model increased by 47%. While, in East Asian region two ports of China and one of South Korea were found efficient on CCR model, with 33% increase on BCC model. Lianyungang port was the most prominent among the efficient ports being highly benchmarked. The average efficiency for East Asian region (CCR: 0.524, BCC: 0.901) remained similar to that of South Asian and Middle East Region (CCR: 0.517, BCC: 0.906).
- Published
- 2021
43. Synergistic effect of silane cross-linker (APTEOS) on PVA/gelatin blend films for packaging applications
- Author
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Muhammad Sarfraz Akram, Farhan Mehmood, Muhammad Zeeshan, Atif Islam, Sadia Sagar Iqbal, Rafi Ullah Khan, Muhammad Rizwan Dilshad, and Nafisa Gull
- Subjects
Materials science ,food.ingredient ,Polymers and Plastics ,Organic Chemistry ,technology, industry, and agriculture ,macromolecular substances ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,complex mixtures ,01 natural sciences ,Silane ,Gelatin ,Polyvinyl alcohol ,0104 chemical sciences ,chemistry.chemical_compound ,food ,chemistry ,Chemical engineering ,Materials Chemistry ,0210 nano-technology ,Cross linker - Abstract
The objective of this work is to fabricate hydrogel films which are biodegradable and also fit for packaging applications. The hydrogel films were prepared by the reaction of polyvinyl alcohol and gelatin with and without 3-aminopropyltriethoxysilane (APTEOS) cross-linker. The hydrogel films were then characterized by FTIR spectroscopy, degree of swelling, TGA, SEM analysis and mechanical testing. The FTIR spectra of the hydrogel films confirmed the presence of both polymers and hydrogen bonding between them. TGA analysis confirmed the increase in thermal stability with the increase of cross-linker amount. SEM analysis confirmed the increase in uniformity of structure with the increase of cross-linker amount. The increase in cross-linker amount resulted in decrease of degree of swelling and increase of tensile strength. The biodegradability of hydrogel films was evaluated by performing soil burial test and found to be decreased with the increase of cross-linker amount. In order to balance the tensile strength and biodegradability, the optimum amount of cross-linker was determined which resulted in the formation of the best performing film. Finally, our best performing film was compared with other hydrogel films reported in the literature. Hence, the hydrogel films cross-linked with APTEOS are biodegradable, having high tensile strength and suitable for packaging purpose.
- Published
- 2021
44. Effect of silica nanoparticles on carbon dioxide separation performances of PVA/PEG cross-linked membranes
- Author
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Waheed Gul Khan, Rafi Ullah Khan, Aamir Ijaz, Muhammad Sajid, Atif Islam, Muhammad Rizwan Dilshad, and Bilal Haider
- Subjects
chemistry.chemical_classification ,Materials science ,General Chemical Engineering ,Plasticizer ,02 engineering and technology ,General Chemistry ,Polymer ,Permeation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Industrial and Manufacturing Engineering ,Methane ,0104 chemical sciences ,chemistry.chemical_compound ,Membrane ,chemistry ,Chemical engineering ,Permeability (electromagnetism) ,Carbon dioxide ,Materials Chemistry ,Fourier transform infrared spectroscopy ,0210 nano-technology - Abstract
Novel PVA/PEG cross-linked membranes were prepared with (0–20 wt. %) of silica nanoparticles. The presence of both the polymers and additive was confirmed by FTIR analysis. The thermal properties of the membranes were analyzed by TGA and DSC analysis. The morphological and mechanical properties of the membranes were studied by SEM analysis and tensile testing, respectively. The gas permeation performances of the membranes were examined using state-of-the-art gas permeability cell. It was found that permeability of all the gases increased with the increase of silica loading, whereas ideal selectivity of carbon dioxide with respect to nitrogen and methane increased up to 10 wt. % loading and then became nearly constant on further loading. 20 wt. % silica loaded membrane was found to be the best performance membrane. The gas permeability of CO2 was also compared with different gas permeation models and was found to be in close agreement with Maxwell Model. The effect of temperature and pressure of feed gas pressure was also studied on permeation performances and optimum performances were achieved around 65 °C. The gas permeation performances were observed to decrease slightly with the increase in feed gas pressure up to 20 bar which confirms the absence of plasticization phenomenon up to 20 bar. Finally, gas permeation performances were compared with 2008 Robeson trade-off lines and it was found that at 20 wt. % loading, gas permeation performances surpassed the trade-off line for CO2/N2, and for CO2/CH4, the gas permeation performances approached the trade-off line.
- Published
- 2021
45. Designing of biocompatible and biodegradable chitosan based crosslinked hydrogel for in vitro release of encapsulated povidone-iodine: A clinical translation
- Author
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Nafisa Gull, Muhammad Taqi Zahid Butt, Saba Zia, Rafi Ullah Khan, Farieha Hussain, Aneela Sabir, Shahzad Khan, Syed Haroon Khalid, Atif Islam, and Misbah Sultan
- Subjects
Drug ,media_common.quotation_subject ,macromolecular substances ,02 engineering and technology ,Electrolyte ,Biochemistry ,Chitosan ,Electrolytes ,03 medical and health sciences ,chemistry.chemical_compound ,Drug Delivery Systems ,X-Ray Diffraction ,Structural Biology ,medicine ,Humans ,Povidone-Iodine ,Molecular Biology ,030304 developmental biology ,media_common ,chemistry.chemical_classification ,Drug Carriers ,0303 health sciences ,technology, industry, and agriculture ,Hydrogels ,General Medicine ,Polymer ,Hydrogen-Ion Concentration ,Biodegradation ,021001 nanoscience & nanotechnology ,Drug Liberation ,Cross-Linking Reagents ,chemistry ,Chemical engineering ,Delayed-Action Preparations ,Drug delivery ,Self-healing hydrogels ,Swelling ,medicine.symptom ,0210 nano-technology ,Hydrophobic and Hydrophilic Interactions ,Porosity - Abstract
Controlled drug delivery is a prime stratagem for minimizing both the frequency of therapeutic administration as well as systematic side effects with high drug content. One of the extensively studied approaches for controlling medicament delivery is the encapsulation of drug within polymer chains which sluggish the release on the basis of its crosslinked network. Recent advances in biomedical field have led to the fabrication of chitosan (CS) based biocompatible and biodegradable hydrogels for controlled delivery of encapsulated drug. In this study, CS-PVP based hydrogels are fabricated by varying the concentration of 3-glycidyloxypropyl trimethoxysilane (GPTMS) via solution casting technique. Swelling indices of prepared hydrogel samples were determined in different media including distilled water, different pH and electrolyte solutions. FTIR, TGA and WAXRD are conducted to evaluate the structural, thermal and crystalline properties of prepared hydrogels, respectively. Porosity (71%), hydrophilicity (55°) and mechanical properties (97.56 MPa of UTS and 85.23% E%) were investigated for the fabricated samples. Extensively in vitro biodegradation, antimicrobial performance and cytotoxicity were evaluated for these hydrogels. The drug release analysis was carried out to examine the release response of encapsulated iodopovidone at physiological conditions. These results tender a strategy for the design of structural hydrogel with different crosslinking mechanism like physical and covalent interactions. These insights obviate the demand for encapsulation and offer promising and translatable strategies for more effective release of drugs.
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- 2020
46. Inflammation targeted chitosan-based hydrogel for controlled release of diclofenac sodium
- Author
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Rafi Ullah Khan, Muhammad Taqi Zahid Butt, Saba Urooge Khan, Nafisa Gull, Sehrish Jabeen, Shahzad Khan, Attaullah Shah, Osama Majeed Butt, Afrasyab Khan, and Atif Islam
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02 engineering and technology ,Biochemistry ,Chitosan ,chemistry.chemical_compound ,Drug Delivery Systems ,X-Ray Diffraction ,Structural Biology ,Spectroscopy, Fourier Transform Infrared ,chemistry.chemical_classification ,Drug Carriers ,0303 health sciences ,Povidone ,Hydrogels ,General Medicine ,Polymer ,021001 nanoscience & nanotechnology ,Controlled release ,Cross-Linking Reagents ,Drug delivery ,Self-healing hydrogels ,Epichlorohydrin ,Swelling ,medicine.symptom ,Rheology ,0210 nano-technology ,Hydrophobic and Hydrophilic Interactions ,Porosity ,Diclofenac ,macromolecular substances ,complex mixtures ,03 medical and health sciences ,Escherichia coli ,medicine ,Animals ,Thermal stability ,Molecular Biology ,030304 developmental biology ,Inflammation ,technology, industry, and agriculture ,Water ,Hydrogen Bonding ,Elasticity ,Drug Liberation ,chemistry ,Chemical engineering ,Delayed-Action Preparations ,Microscopy, Electron, Scanning ,Artemia - Abstract
Inflammation is a key challenge in the treatment of chronic diseases. Spurred by topical advancement in polymer chemistry and drug delivery, hydrogels that release a drug in temporal, spatial and dosage controlled fashion have been trendy. This research focused on the fabrication of hydrogels with controlled drug release properties to control inflammation. Chitosan and polyvinyl pyrrolidone were used as base polymers and crosslinked with epichlorohydrin to form hydrogel films by solution casting technique. Prepared hydrogels were analyzed by swelling analysis in deionized water, buffer and electrolyte solutions and gel fraction. Functional groups confirmation and development of new covalent and hydrogen bonds, thermal stability (28.49%) and crystallinity were evaluated by FTIR, TGA and WAXRD, respectively. Rheological properties including gel strength and yield stress, elasticity (2309 MPa), porosity (75%) and hydrophilicity (73°) of prepared hydrogels were also evaluated. In vitro studies confirmed that prepared hydrogels have good biodegradability, excellent antimicrobial property and admirable cytotoxicity. Drug release profile (87.56% in 130 min) along with the drug encapsulation efficiency (84%) of prepared hydrogels was also studied. These results paved the path towards the development of hydrogels that can release the drugs with desired temporal patterns.
- Published
- 2020
47. Electroactive Polymeric Membranes
- Author
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Maria Wasim, Aneela Sabir, Muhammad Shafiq, and Rafi Ullah Khan
- Published
- 2022
48. Porous Polymers for Membrane Applications
- Author
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Aneela Sabir, Humaira Idrees, Muhammad Shafiq, and Rafi Ullah Khan
- Published
- 2022
49. In-house fabrication of macro-porous biopolymeric hydrogel and its deployment for adsorptive remediation of lead and cadmium from water matrices
- Author
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Muhammad Khalid Azeem, Muhammad Rizwan, Atif Islam, Atta Rasool, Shahzad Maqsood Khan, Rafi Ullah Khan, Tahir Rasheed, Muhammad Bilal, and Hafiz M.N. Iqbal
- Subjects
Ions ,Chitosan ,Water ,Hydrogels ,Hydrogen-Ion Concentration ,Biochemistry ,Water Purification ,Kinetics ,Lead ,Formaldehyde ,Adsorption ,Porosity ,Water Pollutants, Chemical ,General Environmental Science ,Cadmium - Abstract
A novel adsorbent was prepared by blending chitosan (CS) and acrylic acid (AA) while using formaldehyde as a cross linker in the form of hydrogel beads. The adsorption properties of these hydrogel beads for the removal of toxic metal ions (Pb
- Published
- 2022
50. Tactical tuning of mechanical and thermo-mechanical properties of glass fiber/epoxy multi-scale composites by incorporating N-(2-aminoethyl)-3-aminopropyl trimethoxysilane functionalized carbon nanotubes
- Author
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Rizwan Dilshad, Rafi Ullah Khan, Fahd Jamshaid, Adnan Ahmad, Atif Islam, and Muhammad Adrees
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Thermogravimetric analysis ,Materials science ,Polymers and Plastics ,General Chemical Engineering ,Glass fiber ,02 engineering and technology ,Carbon nanotube ,Dynamic mechanical analysis ,Epoxy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,law ,visual_art ,Ultimate tensile strength ,Materials Chemistry ,visual_art.visual_art_medium ,Fourier transform infrared spectroscopy ,Composite material ,0210 nano-technology ,Glass transition - Abstract
The current study explores the potential of N-(2-aminoethyl)-3-aminopropyl trimethoxysilane (AEAPTS) functionalized single-wall carbon nanotubes (f-SWCNTs) as interface modifier to enhance thermomechanical characteristics of glass fiber/epoxy (GF/epoxy) composites. GF/epoxy laminates each embedded with 0.1, 0.3 and 0.5 wt% of pristine SWCNTs (p-SWCNTs) and f-SWCNTs, respectively, were fabricated using hot press technique. Fourier transform infrared spectroscopy demonstrated successful attachment of AEAPTS on SWCNTs while thermogravimetric analysis assessed the grafting density of AEAPTS. Tensile strength, modulus and interlaminar shear strength increased by ~ 27, ~ 14 and ~ 43%, respectively, at 0.5 wt% f-SWCNTs loading. However, no marked improvements were observed in mechanical properties with p-SWCNTs addition. Scanning electron microscopy revealed excellent dispersibility of f-SWCNTs in an epoxy matrix. Moreover, fractographic analysis revealed excellent compatibility of GF and epoxy resin in the presence of f-SWCNTs which accounts for improved interfacial adhesion. Dynamic mechanical thermal analysis showed ~ 40% increment in storage modulus at 25 °C with 0.5 wt% f-SWCNTs content whereas the glass transition temperature remarkably improved by ~ 13 °C as compared to the neat composite (~ 136 °C). The cross-link density increased up to ~ 51% with f-SWCNTs addition implying that grafted AEAPTS moieties undergo a three-way cross-link reaction with epoxide groups of epoxy and silanes of glass fibers. Such multi-scale composites with enhanced strength and thermomechanical stability can replace metallic components in various engineering applications.
- Published
- 2020
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