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An experimental study of heat transfer to boiling liquids under natural convective flow has been carried out in a single tube vertical thermosiphon reboiler to investigate the effect of heat flux and submergence on circulation rates. The test liquids used were distilled water, various concentrations of propan-2-ol in water and their azeotrope. The test section was an electrically heated stainless steel tube of 25.56 mm i.d., 28.85 mm o.d. and 1900 mm long with twenty-one spot welded copper constantan thermocouples to measure the variations in wall temperature along its axis. The uniform heat fluxes in the range of 3.5–42.4 kW/m2 were employed while inlet liquid sub-cooling varied from 0.2 to 30.7 °C. The liquid submergence levels were maintained in the range 30–100%. The typical experimental data has been graphically presented and discussed. An empirical correlation has been developed from the experimental data of the present study through regression analysis. 相似文献
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Nyla Jabeen Qaisar Maqbool Shamaila Sajjad Anam Minhas Umer Younas Sadaf Anwaar Mudassar Nazar Rizwan Kausar Syed Zaheer Hussain 《IET nanobiotechnology / IET》2017,11(5):557
A growing trend within nanomedicine has been the fabrication of self‐delivering supramolecular nanomedicines containing a high and fixed drug content ensuring eco‐friendly conditions. This study reports on green synthesis of silica nanoparticles (Si‐NPs) using Azadirachta indica leaves extract as an effective chelating agent. X‐ray diffraction analysis and Fourier transform‐infra‐red spectroscopic examination were studied. Scanning electron microscopy analysis revealed that the average size of particles formed via plant extract as reducing agent without any surfactant is in the range of 100–170 nm while addition of cetyltrimethyl ammonium bromide were more uniform with 200 nm in size. Streptomycin as model drug was successfully loaded to green synthesised Si‐NPs, sustain release of the drug from this conjugate unit were examined. Prolong release pattern of the adsorbed drug ensure that Si‐NPs have great potential in nano‐drug delivery keeping the environment preferably biocompatible, future cytotoxic studies in this connection is helpful in achieving safe mode for nano‐drug delivery.Inspec keywords: silicon compounds, nanofabrication, nanomedicine, drug delivery systems, nanoparticles, X‐ray diffraction, Fourier transform infrared spectra, scanning electron microscopyOther keywords: nanosilica, streptomycin, nanoscale drug delivery, nanomedicine, silica nanoparticles, Azadirachta indica leaves extract, X‐ray diffraction analysis, Fourier transform‐infrared spectroscopy, scanning electron microscopy, cetyltrimethyl ammonium bromide, SiO2 相似文献
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Fazal Abbas Qaisar Maqbool Mudassar Nazar Nyla Jabeen Syed Zaheer Hussain Sadaf Anwaar Nasir Mehmood Muhammad Saleem Sheikh Talib Hussain Sidra Iftikhar 《IET nanobiotechnology / IET》2017,11(8):935
To grapple with multidrug resistant bacterial infections, implementations of antibacterial nanomedicines have gained prime attention of the researchers across the globe. Nowadays, zinc oxide (ZnO) at nano‐scale has emerged as a promising antibacterial therapeutic agent. Keeping this in view, ZnO nanostructures (ZnO‐NS) have been synthesised through reduction by P. aphylla aqueous extract without the utilisation of any acid or base. Structural examinations via scanning electron microscopy (SEM) and X‐ray diffraction have revealed pure phase morphology with highly homogenised average particle size of 18 nm. SEM findings were further supplemented by transmission electron microscopy examinations. The characteristic Zn–O peak has been observed around 363 nm using ultra‐violet–visible spectroscopy. Fourier‐transform infrared spectroscopy examination has also confirmed the formation of ZnO‐NS through detection of Zn–O bond vibration frequencies. To check the superior antibacterial activity of ZnO‐NS, the authors'' team has performed disc diffusion assay and colony forming unit testing against multidrug resistant E. coli, S. marcescens and E. cloacae. Furthermore, protein kinase inhibition assay and cytotoxicity examinations have revealed that green fabricated ZnO‐NS are non‐hazardous, economical, environmental friendly and possess tremendous potential to treat lethal infections caused by multidrug resistant pathogens.Inspec keywords: nanomedicine, zinc compounds, II‐VI semiconductors, wide band gap semiconductors, nanoparticles, scanning electron microscopy, X‐ray diffraction, antibacterial activity, transmission electron microscopy, particle size, Fourier transform infrared spectra, ultraviolet spectra, visible spectra, enzymes, biochemistry, molecular biophysics, microorganisms, drugs, toxicology, bonds (chemical), semiconductor growth, nanofabrication, vibrational modesOther keywords: green synthesised zinc oxide nanostructures, Periploca aphylla extract, antibacterial potential, multidrug resistant pathogens, multidrug resistant bacterial infections, antibacterial nanomedicines, P. aphylla aqueous extract, structural examinations, scanning electron microscopy, X‐ray diffraction, pure phase morphology, homogenised average particle size, SEM, transmission electron microscopy, Fourier‐transform infrared spectroscopy, bond vibration frequency, antibacterial activity, disc diffusion assay, colony forming unit testing, S. marcescens, E. cloacae, E. coli, ultraviolet‐visible spectroscopy, protein kinase inhibition assay, cytotoxicity, lethal infections, ZnO 相似文献
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Bilayer SiO2 Nanorod Arrays as Omnidirectional and Thermally Stable Antireflective Coating 下载免费PDF全文
Sadaf B. Khan Hui Wu Jianghao Li Limin Chen Zhengjun Zhang 《Advanced Engineering Materials》2018,20(5)
5.
Model-driven assessment of system dependability 总被引:1,自引:0,他引:1
Sadaf Mustafiz Ximeng Sun Jörg Kienzle Hans Vangheluwe 《Software and Systems Modeling》2008,7(4):487-502
Designers of complex real-time systems need to address dependability requirements early on in the development process. This
paper presents a model-based approach that allows developers to analyse the dependability of use cases and to discover more
reliable and safe ways of designing the interactions of the system with the environment. The hardware design and the dependability
of the hardware to be used also needs to be considered. We use a probabilistic extension of statecharts to formally model
the interaction requirements defined in the use cases. The model is then evaluated analytically based on the success and failure
probabilities of events. The analysis may lead to further refinement of the use cases by introducing detection and recovery
measures to ensure dependable system interaction. A visual modelling environment for our extended statecharts formalism supporting
automatic probability analysis has been implemented in AToM3, A Tool for Multi-formalism and Meta-Modelling. Our approach is illustrated with an elevator control system case study.
相似文献
Hans VangheluweEmail: |
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This qualitative study explored pre-service teachers' behavioral, normative, and control beliefs regarding their intentions to use Web 2.0 technologies in their future classrooms. The Theory of Planned Behavior (TPB) was used as the theoretical framework (Ajzen, 1991) to understand these beliefs and pre-service teachers' intentions for why they want to use Web 2.0 technologies. According to Ajzen's TPB, the behavioral beliefs are based on attitude toward outcomes or consequences of using Web 2.0, the normative beliefs depend on social support and social pressure to use Web 2.0, and the control beliefs lay the foundation of perceived behavioral control over using Web 2.0 in a classroom. Data were collected from open-ended survey questions (n = 190), semi-structured interviews (n = 12) and end of semester reflections (n = 12). Findings suggest that pre-service teachers' intentions to use Web 2.0 technologies are related to their beliefs about the value of these technologies for improving student learning and engagement, its ease of use (behavioral beliefs), its ability to meet the needs/expectations of digital age students (normative beliefs), the participants' high self-efficacy in use, and its potential for affording students anytime/anywhere access to learning and interaction (control beliefs). From these results, we recommend that teacher educators should target these beliefs within teacher development programs to prepare pre-service teachers for successful use of Web 2.0 technologies in their future K-12 classrooms. 相似文献
7.
Kalsoom Anum Maqsood Muazzam Yasmin Sadaf Bukhari Maryam Shin Zian Rho Seungmin 《The Journal of supercomputing》2022,78(7):9668-9690
The Journal of Supercomputing - A multimedia-based medical decision-making system is an ultimate requirement in the medical imaging domain. In the healthcare sector, achieving quick and efficient... 相似文献
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The feasibility of using peanut husk biomass for the removal of Indosol Orange RSN dye was explored during this study. Batch experiments were conducted with native, polyethyleneimine (PEI) treated and Na-alginate immobilized biomass. Different important process parameters like pH, contact time, biosorbent dose, initial dye concentration, and temperature were optimized during batch study. Low pH and low biosorbent dose were found to be the feasible conditions for the maximum biosorption of dye. PEI-treated biomass exhibited maximum biosorption capacity (79.5 mg g?1) for Indosol Orange RSN dye. Pseudo-second-order equation generated the best agreement with experimental data. Different equilibrium isotherm models were applied to the experimental data. Langmuir adsorption isotherm model showed better fitness to the experimental results. Biosorption process was found to be exothermic in nature and thermodynamic study was carried out to check out the feasibility of process. Continuous mode study was performed with native peanut husk biomass to optimize the bed height, flow rate, and initial dye concentration for maximum dye removal. The results indicate that maximum dye removal (8.8 mg L?1) was obtained with 3 cm bed height and 1.8 mL min?1 flow rate by using 70 mg L?1 initial dye concentration. Characterization of biosorbent was carried out by determination of point of zero charge, scanning electron microscopy, and Fourier transform infrared spectroscopy. The findings revealed that peanut husk biomass has a high biosorption potential, and it can be exploited for the treatment of dye containing waste water. 相似文献
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Yasir Ul Haq Imran Murtaza Sadaf Mazhar Naeem Ahmad Awais A. Qarni Zeeshan Ul Haq Shahid A. Khan Mahmood Iqbal 《应用聚合物科学杂志》2020,137(40):49197
Electric power system applications demand for high-temperature dielectric materials. The improved performance of polymer nanocomposites requires improvement in their thermal conductivity & stability, dielectric stability and processing technique. However, they often lose their dielectric properties with a rise in temperature. Here, we offer a solution by incorporating electrically conducting material (MXene) and semiconducting inorganic nanoparticles (ZnO NPs) into an insulating PMMA polymer matrix to maintain high dielectric constant, both at the room and high temperature. Therefore, to achieve desirable thermal and dielectric properties is the main objective of the present study based on the homogeneous distribution of the nanofillers by in-situ bulk polymerization assisted by strong sonication in the corresponding polymer. The introduction of MXene and ZnO NPs into the PMMA not only acquires a substantial increment in the dielectric constant, to attain a value 437, with minimum energy loss of 0.36 at 25 Hz, but also improves the thermal conductivity of PMMA up to 14 times by causing the reduction of thermal resistance, which is actually responsible for the poor thermal conductivity of amorphous pure PMMA polymer. More importantly, hybrid PMMA/4:2 wt% MXene:ZnO nanocomposite leads to an excellent thermal stability. Moreover, further characterization of the synthesized nanocomposites by FTIR, SEM and XRD leads to the evaluation of strong interaction of ternary components with PMMA matrix. 相似文献