148 research outputs found
Synthesis and evaluation of radioactive gold nanoparticles for cancer treatment and imaging
This research study explores an appropriate method for production of radioactive gold nanoparticles that may be more appropriate for treating cancer. The first protocol includes using a nontoxic and antitumor phytochemical reductant agent, Mangiferin that can be used to produce radioactive gold nanoparticles to treat and image prostate cancer while the second protocol uses sodium citrate as reductant agent to produce radioactive gold-199 nanoparticles that can be used for imaging. Also in this research, MCNP code was used to build a simple geometrical model of a human prostate, and then estimate the dose distribution that is deposited by radioactive gold nanoparticles (198AuNPs or 199AuNPs). The results from in vivo evalution of MGF-198AuNPs indicated that MGF-198AuNPs have significant therapeutic effect and they were able to control the tumor size in comparison to control group. Also, In vivo evaluation results of radioactive citrate-199AuNPs showed that citrate-199AuNPs are stable in vivo and therefore, they can be used in imaging procedures. The results of MCNP simulations showed that the deposited dose by 198AuNPs or 199AuNPs, which are distributed homogenously in the tumor, has highest value at the tumor region and then decreases exponentially toward the normal tissue in the prostate as well as surrounding organs
Numerical and experimental study of new designs of all-vanadium redox flow batteries for performance improvement
Energy storage is envisioned as a key part of a renewable energy solution incorporated in a grid that overcomes two critical limits of renewable energy: intermittency and uncertainty. Among various technologies, a vanadium redox flow battery (VRFB) offers a promise because of its unique features such as long cycle life, separation of energy and power ratings, and capability of a deep discharge. The remaining challenges, however, include the limited application due to low energy density and complicated geometries. The complex geometry makes it difficult to optimize the performance and can cause a serious concern about leakage of the liquid. The goal of this dissertation is to resolve these challenges through modeling and experimental studies for newly-designed VRFB. The topic can be divided into three main efforts: flow field optimization by optimizing channels, new design for stability improvement and cost reduction, and a new concept of distributed VRFB.
First, the effects of channel and length on battery performance were investigated based on 3D electrochemical models validated by experimental measurements. Second, to address the drawbacks of traditional VRFB, a new design has been introduced to increase reliability, reduce costs, and ease assembly. This battery has a small number of parts, which can more effectively prevent electrolyte leakage. Based on PVC (polyvinyl chloride) material, it solves the problem caused by electrolyte penetration by replacing existing graphite plate. Third, the development of a new distributed VRFB for transport systems addresses the problem of insufficient power, one of the main challenges of the flow system. This new technology is more efficient for space utilization, equal weight distribution, and fueling like a gasoline vehicle, reducing charge time --Abstract, page iv
Consumption profile based analysis of solar thermal system for DHW in buildings
Solar thermal system for domestic hot water (DHW) is one of the most common application for utilizing solar energy. Consumption profile of hot water has a significant impact on solar DHW sizing as it relates many uncertainties regarding human nature, which is difficult to predict therefore. The size of solar thermal system is roughly estimated in most cases which can results operational difficulties and efficiency losses. In this paper, different DHW consumption profiles have been analysed. The influential parameters on consumption, sizing methods and proposed modelling techniques for solar DHW are discussed and concluded with findings of several case studies
Identifying cloud security threats to strengthen cloud computing adoption framework
Cloud Computing allows firms to outsource their entire information technology (IT) process, allowing them to concentrate more on their core business to enhance their productivity and innovation in offering services to customers. It allows businesses to cut down heavy cost incurred over IT infrastructure without losing focus on customer needs. However, to a certain limit adopting Cloud computing has struggled to grow among many established and growing organizations due to several security and privacy related issues. Throughout the course of this study several interviews were conducted, with cloud developers and security experts, and the literature was reviewed. This study enabled us to understand, current and future, security and privacy challenges with cloud computing. The outcome of this study led to identification of total 18, current and future, security issues affecting several attributes of cloud computing
A short review on passive strategies applied to minimise the building cooling loads in hot locations
Cooling and air-conditioning systems are responsible for the highest energy consumption in buildings located in hot areas. This high share does not only increase the building energy demand cost but also increases the environmental impact, the topmost awareness of the modern era. The development of traditional systems and reliance on renewable technologies have increased drastically in the last century but still lacks economic concerns. Passive cooling strategies have been introduced as a successful option to mitigate the energy demand and improve energy conservation in buildings. This paper shed light on some passive strategies that could be applied to minimise building cooling loads to encourage the movement towards healthier and more energy-efficient buildings. For this purpose, seven popular passive technologies have been discussed shortly: multi-panned windows, shading devices, insulations, green roofing, phase change materials, reflective coatings, and natural ventilation using the windcatcher technique. The analysis of each strategy has shown that the building energy could be improved remarkably. Furthermore, adopting more passive strategies can significantly enhance the building thermal comfort even under severe weather conditions
A short review on passive strategies applied to minimise the building cooling loads in hot locations
Cooling and air-conditioning systems are responsible for the highest energy consumption in buildings located in hot areas. This high share does not only increase the building energy demand cost but also increases the environmental impact, the topmost awareness of the modern era. The development of traditional systems and reliance on renewable technologies have increased drastically in the last century but still lacks economic concerns. Passive cooling strategies have been introduced as a successful option to mitigate the energy demand and improve energy conservation in buildings. This paper shed light on some passive strategies that could be applied to minimise building cooling loads to encourage the movement towards healthier and more energy-efficient buildings. For this purpose, seven popular passive technologies have been discussed shortly: multi-panned windows, shading devices, insulations, green roofing, phase change materials, reflective coatings, and natural ventilation using the windcatcher technique. The analysis of each strategy has shown that the building energy could be improved remarkably. Furthermore, adopting more passive strategies can significantly enhance the building thermal comfort even under severe weather conditions
Numerical Study of Cuttings Transport of Nanoparticle-Based Drilling Fluid
Cuttings transportation from the drill bit, through the annulus, to the surface is one of the most important functions performed by drilling fluid. The prediction of drilling fluid's performance to transport cuttings in the annulus is very complex task due to the presence of numerous parameters. Nanoparticles (NPs) have been recently introduced into drilling fluid to engineer its properties and enhance its performance. Nevertheless, the lifting capacity has not been sufficiently investigated. The understanding of the influence and the mechanisms responsible for the improvement in cuttings transport process can further advance the application of NPs for drilling fluids. Computational fluid dynamics (CFD) is widely used as a numerical technique in handling complex multiphase flow problems in different operational conditions. The present work has taken the advantages of CFD to computationally analyze the influence of NPs and the effects of various parameters such as drilling fluids rheology, flow rate, pipe rotation, cuttings density, shape, concentration, and drilling fluids-cuttings particle coupling regimes on the cuttings transport in a vertical wellbore. The CFD simulation is carried out by using transient solver of ANSYS-FLUENT commercial code. The dense discrete phase model is used to overcome the main shortcomings of previous Eulerian based approaches. Good agreement has been achieved between the simulation and the published experimental results. It showed that the fluid viscosity and cuttings transport process can be significantly enhanced by adding nanomaterials to the fluid, and the process is highly influenced by cuttings characteristics such as in situ concentration, shape, and density
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