Mustafa Y. Haddad  Hamad F. Alharbi 《应用聚合物科学杂志》2019,136(11):47209

This article describes the adsorption and tensile behavior of electrospun polyacrylonitrile (PAN) nanofiber mats loaded with different amounts of ZnO [0.5, 1.0, 2.0, and 5.0 wt%] nanoparticles. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transforminfrared (FTIR) spectroscopy, and thermal gravimetric analysis (TGA) were utilized to characterize the resulting composite nanofibers. Microscopic investigations revealed that the increase in surface roughness and diameter of the electrospun PAN nanofibers was due to the addition of ZnO nanoparticles. Adsorption results indicated that the fabricated PAN/ZnO (2.0 wt%) composite nanofiber mats showed the best adsorption performance with 261% and 167% increase in adsorption capacities for Pb(II) and Cd(II) from aqueous solutions, respectively, compared to pristine PAN nanofibers. The adsorption equilibrium was reached within 60 min, and the process could be described using the nonlinear pseudo-second-order kinetic model. The adsorption isotherm study was better represented by the Langmuir model, which suggested a homogeneous distribution of the monolayer adsorptive sites on the surface of the composite nanofibers. Mechanical testing revealed that the decrease in tensile strength and elongation at breakof the PAN/ZnO composite nanofiber mats was due to the formation of some bead defects and agglomerates within the structure of the PAN nanofibers. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47209.  相似文献   

    

Abhishek Biswas  Mahesh R. G. Prasad  Napat Vajragupta  Hamad ul Hassan  Florian Brenne  Thomas Niendorf  Alexander Hartmaier 《Advanced Engineering Materials》2019,21(7)

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Abdulrahman Almutairi  Mohamed Zedan  Hamad M. Alhajeri  Abdulrahman Alenezi 《亚洲传热研究》2020,49(5):2717-2745

In this study, the performance of several gas turbine engines has been investigated using computational modelling based on the actual manufacturer's data. Further, the study focuses on evaluating the impact of varying the configuration of the compressor on overall engine performance based on the first and second laws of thermodynamics. The results confirm that the main source of irreversibilities occurs in the combustion chamber in all cases. The exergetic efficiency of the gas turbine engine significantly varies with compressor configurations, type of compressors, load variation, climatic condition, and isentropic efficiency. The engine capacity and high‐pressure turbine inlet temperature govern the gas turbine performance, and higher values are more favourable. The gas turbine exergetic efficiency drops off when the power setting adjusted at part‐load and at high ambient temperature. The most optimal gas turbine performance is located at the single axial compressor case, followed by the axial‐centrifugal compressor and then the centrifugal–centrifugal compressor.  相似文献   

    

Deepak Meerakaviyad  Tony Keville  Atma Prakash  Abdullah Sajid  Faik Hamad 《亚洲传热研究》2020,49(5):2849-2867

The multiphase flow pumps cover a wide range of industrial sectors extending across petrochemical, metallurgy, and dredging, chemical industry, paint, and construction. The major application is the handling of wet gas and vapor that will condense partially during the compression stage. The main progress in the area of multiphase pumps has been the innovation of a computational fluid dynamics (CFD) numerical approach to simulate three‐dimensional flows inside the pump and to predict pump performance. CFD undoubtedly constitutes one of the most promising approaches for the design, analysis, and performance assessment of complex machines. However, practical application of the CFD tool to determine the internal flow field in multiphase pumps is still far from reality owing to the limitations of a detailed three‐dimensional model of the pump and accuracy of multiphase flow simulation. This review accentuates the influence of different geometrical and dynamical parameters on the performance of the pump and the use of CFD simulation to predict the detailed flow patterns of fluid mixtures. CFD analysis has unearthed the fact that the pattern of inner flow varies with the flow rate and concentration of each phase and the rotation speed of the impeller and number of blades were also found to considerably impact pump performance.  相似文献   

    

Mohammad Hayal Alotaibi  Yahya A. Alzahrani  Neha Arora  Ahmed Alyamani  Abdulrahman Albadri  Hamad Albrithen  Ibrahim H. Al-Lehyani  Sultan M. Alenzi  Ali Z. Alanzi  Fahad S. Alghamdi  Shaik M. Zakeeruddin  Simone Meloni  M. Ibrahim Dar  Michael Graetzel 《Solar RRL》2020,4(2)

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Umer M. Chaudry  Kotiba Hamad 《Polymer Engineering and Science》2019,59(11):2273-2278

In this study, we fabricated and studied properties of ternary polymer blends containing polylactic acid (PLA), polypropylene (PP), and acrylonitrile‐butadiene‐styrene (ABS). The melt rheology experiments showed that the present combination (PLA/PP/ABS) exhibited a melt process‐ability, which is comparable to those of individual components. The ternary blends prepared in this work can be exploited to fabricate hierarchically porous PLA materials for biomedical applications. POLYM. ENG. SCI., 59:2273–2278, 2019. © 2019 Society of Plastics Engineers  相似文献   

    

Nzar Shakr Piro  Ahmed Salih Mohammed  Samir M. Hamad  Rawaz Kurda  Bootan S. Qader 《Structural Concrete》2023,24(2):2093-2112

To preserve the environment and natural resources, steel slag recovery conserves natural resources and makes landfill space available. Steel slag as a waste material has been partially substituted for fine (sand) and coarse aggregate in concrete (gravel). Compressive strength (CS) is the most significant mechanical attribute for all forms of concrete composites. To save time, energy, and money, it is essential to create accurate models for forecasting the CS of normal concrete (NC). In addition, it offers essential information for organizing the building work and details the ideal time to remove the formwork. In total, 338 data points were gathered, processed, and modeled in total. During the modeling approach, the most influential elements impacting the compressive strength (CS) of concrete with steel slag replacement were addressed. According to the modeling method, the most effective parameter which affects the compressive strength of normal concrete is the curing time. This research employed a Multi Logistic Regression model (MLR), an Artificial Neural Network (ANN), a Full Quadratic model (FQ), an M5P-tree model, and an Interaction model to predict the compressive strength of normal strength concrete (CS ranged from 10 to 55 MPa) with steel slag aggregate replacement. According to data from the literature, the steel slag concentration enhanced the compressive strength. Based on evaluations with statistical tools like the objective (OBJ) function, the scatter index, and the Taylar diagram, the ANN model with the lowest root mean square error did better at predicting compressive strength than the other models.  相似文献   

    

Young Gun Ko  Kotiba Hamad 《Advanced Engineering Materials》2017,19(6)

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Shimrit Heiliczer  Asaf Wilensky  Tal Gaver  Olga Georgiev  Sharleen Hamad  Alina Nemirovski  Rivka Hadar  Yair Sharav  Doron J. Aframian  Joseph Tam  Yaron Haviv 《International journal of molecular sciences》2022,23(21)

The endocannabinoid system is involved in physiological and pathological processes, including pain generation, modulation, and sensation. Its role in certain types of chronic orofacial pain (OFP) has not been thoroughly examined. By exploring the profiles of specific salivary endocannabinoids (eCBs) in individuals with different types of OFP, we evaluated their use as biomarkers and the influence of clinical parameters and pain characteristics on eCB levels. The salivary levels of anandamide (AEA), 2-arachidonoyl glycerol (2-AG), and their endogenous breakdown product arachidonic acid (AA), as well as the eCB-like molecules N-palmitoylethanolamide (PEA) and N-oleoylethanolamide (OEA), were assessed in 83 OFP patients and 43 pain-free controls using liquid chromatography/tandem mass spectrometry. Patients were grouped by diagnosis: post-traumatic neuropathy (PTN), trigeminal neuralgia (TN), temporomandibular disorder (TMD), migraine, tension-type headache (TTH), and burning mouth syndrome (BMS). Correlation analyses between a specific diagnosis, pain characteristics, and eCB levels were conducted. Significantly lower levels of 2-AG were found in the TN and TTH groups, while significantly lower PEA levels were found in the migraine group. BMS was the only group with elevated eCBs (AEA) versus the control. Significant correlations were found between levels of specific eCBs and gender, health-related quality of life (HRQoL), BMI, pain duration, and sleep awakenings. In conclusion, salivary samples exhibited signature eCBs profiles for major OFP disorders, especially migraine, TTH, TN, and BMS. This finding may pave the way for using salivary eCBs biomarkers for more accurate diagnoses and management of chronic OFP patients.  相似文献   

    

Mohd Sajid Ali  Md Tabish Rehman  Hamad Al-Lohedan  Mohamed Fahad AlAjmi 《International journal of molecular sciences》2022,23(8)

The interaction of the important plasma protein, human serum albumin (HSA), with two monoterpenes found in cumin oil, i.e., cuminaldehyde (4-isopropylbenzaldehyde) and cuminol (4-isopropylbenzyl alcohol), was studied in this paper. Both experimental and computational methods were utilized to understand the mechanism of binding. The UV absorption profile of HSA changes in the presence of both cuminaldehyde and cuminol, due to the interaction between HSA with both monoterpenes. The intrinsic fluorescence intensity of HSA was also quenched on the sequential addition of both ligands, due to change in the microenvironment of the fluorophore present in the former. Quenching of HSA by cuminaldehyde was much higher in comparison to that in the presence of cuminol. Fluorescence quenching data were analyzed using modified Stern-Volmer and Lineweaver-Burk methods, which suggested that the binding mechanism was of a static type for both ligands. In both cases, the binding was favored by the domination of hydrophobic as well as hydrogen bonding/Van der Waals forces. Both ligands partially unfolded the secondary structure of HSA, although the effect of cuminaldehyde was more pronounced, as compared to cuminol. The preferred binding site of cuminaldehyde and cuminol inside HSA was also the same; namely, drug binding site 1, located in subdomain IIA. The study showed that cuminaldehyde binds strongly with albumin as compared to its alcohol counterpart, which is due to the more hydrophobic nature of the former.  相似文献