NATIRT – Model of the Loss of Flow Transient for Tajoura Research Reactor with LEU Fuel
Journal ArticleDesign parameters are presented for Tajoura reactor core utilizing the new fuel assemblies with low enriched uranium (LEU, using IRT-4M fuel assemblies) in the steady state safety operational parameters and Loss of Flow transient mathematical models (NATIRT - computer program. The calculated results of the model are presented in the cases of forced convection steady state, transient during emergency tank filling and natural convection after emergency tank filling modes at different reactor core thermal power level. The results of NATIRT for all cases of flow were in good agreement with the PARET and PLTEMP computer programs.
Hmza Ashur Milad Mohamed, (01-2021), USA: IJSRED, 4 (5), 1-9
Hybrid CHP/Geothermal Borehole System for Multi-Family Building in Heating Dominated Climates
Journal ArticleAbstract: A conventional ground-coupled heat pump (GCHP) can be used to supplement heat
rejection or extraction, creating a hybrid system that is cost-eective for certainly unbalanced climes.
This research explores the possibility for a hybrid GCHP to use excess heat from a combined heat
power (CHP) unit of natural gas in a heating-dominated environment for smart cities. A design for
a multi-family residential building is considered, with a CHP sized to meet the average electrical
load of the building. The constant electric output of the CHP is used directly, stored for later use in a
battery, or sold back to the grid. Part of the thermal output provides the building with hot water,
and the rest is channeled into the GCHP borehole array to support the building’s large heating needs.
Consumption and weather data are used to predict hourly loads over a year for a specific multi-family
residence. Simulations of the energies exchanged between system components are performed, and a
cost model is minimized over CHP size, battery storage capacity, number of boreholes, and depth of
the borehole. Results indicate a greater cost advantage for the design in a severely heated (Canada)
climate than in a moderately imbalanced (Ohio) climate.
Saeed Alqaed, Jawed Mustafa, Kevin P. Hallinan, Rodwan Elhashmi, (09-2020), Sustainability: MDPI, 12 (18),
Rayleigh Model of Radiation Heat Transfer in Spherical Medium
Journal ArticleIn certain extremely low probability, severe accident scenarios which have been postulated for liquid metal cooled fast reactors, large bubble cavities containing fuel vapor and fission products transit a layer of coolant and release this material to the cover gas thereby presenting a contribution to an accident-specific source term [5]. Rayleigh model in radiation heat transfer has been investigated to analysis and interpret the experiments that conducted during 1980's for oxide UO 2 fueled reactors in Fuel Aerosol Simulant Test (FAST) facility at Oak Ridge National Laboratory (ORNL).These analyses are applied to estimate the bubble collapse of Liquid Metal reactors (LMR's) during a hypothetical core disruptive accident (HCDA). In Rayleigh non-scattering model the particle size was 0.01 µm [6],and according to Mie theory principle, the absorption coefficient for small particle-size distribution was estimated (k = 10 m-1 was used) from reference [7] at complex refractive index of UO 2 at λ = 600 µm and x = 0.0785.A MATLAB code was used to solvethe radiative heat equation (RTE) in spherical coordinates. The mixture is in local thermodynamic equilibrium inside the bubble which has a black body surface boundary.The mixture in the cavity contains three components: the non-condensable gas Xenon, Uranium dioxide vapor, and fog.To simulate fuel bubble's geometry as realistically as possible, according to experimental observation, the energy equation in a spherical coordinate system has been solved with the radiative flux heat transfer equation (RTE) to obtain the effect of fuel bubble's geometry on the transient radiative heat flux and to predict the transient temperature distribution in the participating medium during a hypothetical core disruptive accident (HCDA) for liquid metal fast breeding reactor (LMFBR) for FAST. The transient temperature distribution in fog region was utilized to predict the amount of condensable UO 2 vapor = − ! " ! #. The conclusion that can be drawn from the present study, is that the Fuel Aerosol Simulant Test (FAST) facility at Oak Ridge National Laboratory has a larger margin of safety since the bubble rising time is greater than the bubble collapse time.
Hmza Ashur Milad Mohamed, (09-2020), USA: IJSRED, 3 (5), 421-437
Mie MODEL OF RADIATION HEAT TRANSFERIN ISOTHERMAL SPHERICAL MEDIUM
Journal ArticleIn certain extremely low probability, severe accident scenarios which have been postulated for liquid metal cooled fast reactors,large bubble cavities containing fuel vapor and fission products transit a layer of coolant and release this material to the cover gas thereby presenting a contribution to an accident-specific source term [5].Mie model in radiation heat transfer has been investigated to analysis and interpret the experiments that conducted during 1980's for oxide UO 2 fueled reactors in Fuel Aerosol Simulant Test (FAST) facility at Oak Ridge National Laboratory (ORNL).These analyses are applied to estimate the bubble collapse of Liquid Metal reactors (LMR's) during a hypothetical core disruptive accident (HCDA).InMie scattering model the particle size was 0.07 µm [6]. The scattering coefficient of UO 2 particles (σ = 1.24 m-1), was calculated by using Mie theory,at the same number of stable nuclei's N (2.9 E15 nuclei/m 3) that resulted from theabsorbed coefficientk = 0.082 m-1 [7].P 1 approximation method was used to solve the radiative heat transfer equation (RTE) in spherical coordinates of participating medium confined between the two concentric spheres.The surfaces of the spheres are assumed to be gray, diffusely emitting and diffusely reflecting boundaries, and an isothermal boundary conditions were assumed at these surfaces.Marsak's boundary condition was to computed, the net radiative heat flux q(τ), and the incident radiation G(τ), to analyze and interpret the CVD experiments data that were conducted in the FAST facility at ORNL [8] and Fast Flux Test Facility reactor (FFTF) in Argonne National Laboratory ANL.The conclude that extracted from this study is greater margin of safety when the bubble rising time is greater than the bubble collapse time since the bubble collapses (UO 2 condenses) before it can reach the top of the vessel therefore there is less chance of release of aerosol as in Oak Ridge National Laboratory (ORNL) FAST experiments and Argonne National Laboratory (FFTF) reactor.
Hmza Ashur Milad Mohamed, (09-2020), USA: IJSRED, 3 (5), 402-420
Low-energy opportunity for multi-family residences: A review and simulation-based study of a solar borehole thermal energy storage system
Journal ArticleThe multi-family residential building sector is the least energy efficient in the United States, thus allowing for ample opportunities for significant cost-effective energy and carbon savings. In the present study, we propose a district solar borehole thermal solar energy storage (BTES) system for both retrofit and new construction for a multi-family residence in the Midwestern United States, where the climate is moderately cold with very warm summers. Actual apartment interval power and water demand data was mined and used to estimate unit level hourly space and water heating demands, which was subsequently used to design a cost-optimal BTES system. Using a dynamic simulation model to predict the system performance over a 25-year period, a parametric study was conducted that varied the sizes of the BTES system and the solar collector array. A life-cycle cost analysis concluded that is it possible for an optimally-sized system to achieve an internal rate of return (IRR) of 11%, while reducing apartment-wide energy and carbon consumption by 46%. Both a stand-alone and solar-assisted ground-source heat pump system were designed and simulated for comparison to the BTES system, and found to be less economically favorable than the solar BTES system. Thus, the promise for district-scale adoption of BTES in multi-family residences is established, particularly for new buildings.
Rodwan Elhashmi, Kevin P. Hallinan, Andrew D. Chiasson, (08-2020), Energy: Pergamon, 204
Parametric modeling and simulation of Low temperature energy storage for cold-climate multi-family residences using a geothermal heat pump system with integrated phase change material storage tank
Journal ArticleA novel geothermal heat pump (GHP) system with an integrated low- to moderate-temperature salt hydrate phase change material (PCM) storage tank for buildings in cold climates is proposed in this study. The purpose of the PCM storage tank is to dampen peak heating loads and to remove annual ground thermal load imbalances on the ground heat exchanger (GHX) to assist in achieving an optimally-sized GHX. As heat is extracted from the closed-loop system by heat pumps in heating mode, a significant portion of this heat is used to solidify a salt hydrate PCM. This heat of fusion is later released back into the heat transfer fluid, storing it in the PCM tank and GHX for later diurnal and seasonal use. To examine the merits of the proposed concept, electric utility meter data on 15-minute time intervals were mined from an actual apartment building and used to estimate space heating, cooling, and hot water heating loads. Those data were used in an hourly, dynamic 20-year life-cycle simulation model in TRNSYS to design an optimum combination of GHX and PCM storage, where each component was sized to balance the annual ground thermal loads. The system simulation results show significant potential for GHX size reduction with a PCM storage tank, but the system is quite sensitive to the PCM melt temperature due to significant hysteretic nature of the salt hydrate PCM heating and cooling curves. We also find that there is no unique optimum unless other factors are considered such as installation cost and physical constraints; many combinations of GHX size and PCM mass are capable of achieving the design goal with similar annual electric energy consumption. For the cases examined here, a PCM melt temperature of 27 °C yields the most favorable economic results, and a preliminary economic analysis suggests that with typical drilling cost and PCM tank cost values, the GHX size can be reduced by over 50 %.
A. Alkhwildi, R. Elhashmi, A. Chiasson, (07-2020), Geothermics: Pergamon, 86 (32767),
Applications of EOQ Technique to Reduce Inventory Costs in Industrial Sectors: A Case Study on a Water Desalination and Bottling Plant in Libya
Journal ArticleThe purpose of this paper is to minimize the total cost of raw material inventory for
water desalination and bottling plant resulting in a more profitable approach in
accordance with the production needs. The classical application of Economic Order
Quantity is used to support this paper and in order to reduce the costs related to
inventory. For this purpose, this method generates a minimum total inventory cost by
finding when ordering cost and carrying cost are equal. From this result, the inventory
level and the number of raw material demand become more economically suitable with
the production needs. It is because this method applies two types of cost, carrying cost
and ordering cost that make the total inventory cost more productive. So, this method
can be used to get the most economical total inventory cost and reduce storage cost
swelling. And hence, decreasing costs means that more profit is achieved.
Elbahlul M Abogrean, (06-2020), مجلة البحوث العلمية: جامعة أفريقيا, 10 (5), 125-130
RADIATION HEAT TRANSFER ANALYSIS IN TWO-PHASE MIXTURE ASSOCIATED WITH LIQUID METAL REACTOR ACCIDENTS
PhD ThesisAnalytical study associated with liquid-metal fast breeder reactor (LMFBR) has been investigated by using scattering and non-scattering mathematical radiation models. In the nonscattering model, the radiative transfer equation (RTE) was solved together with the continuity equations of mixture components under local thermodynamic equilibrium. A MATLAB code was used to solve these equations. This application employed a numerical integration to compute the temperature distribution within the bubble and the transient wall heat flux. First, in Rayleigh nonscattering model the particle size was 0.01 µm [6], and according to Mie theory principle, the absorption coefficient for small particle –size distribution was estimated (k = 10 m-1 was used) from reference [7] at complex refractive index of UO2 at λ = 600 µm and x = 0.0785. A MATLAB code was used to solve the radiative heat equation (RTE) in spherical coordinates. The mixture is in local thermodynamic equilibrium inside the bubble which has a black body surface boundary. The mixture in the bubble contains three components: the non-condensable gas Xenon, Uranium dioxide vapor, and fog. To simulate fuel bubble’s geometry as realistically as possible, according to experimental observation, the energy equation in a spherical coordinate system has been solved with the radiative flux heat transfer equation (RTE) to obtain the effect of fuel bubble’s geometry on the transient radiative heat flux and to predict the transient temperature iv distribution in the participating medium during a hypothetical core disruptive accident (HCDA) for liquid metal fast breeding reactor (LMFBR) for FAST. The transient temperature distribution in fog region was used to predict the amount of condensable UO2 vapor. The conclusion that can be drawn from the present study, is that the Fuel Aerosol Simulant Test (FAST) facility at Oak Ridge National Laboratory has a larger margin of safety since the bubble rising time is greater than the bubble collapse time. Second in the scattering model, the spherical harmonics method was used to solve the radiative heat transfer equation (RTE) in spherical coordinates, and the particle size was 0.07 µm [6]. The scattering coefficient of UO2 particles (σ = 1.24 m-1 ), was calculated using Mie theory at the same number of stable nuclei N (2.9 E15 nuclei/m3 ) that resulted from the absorption coefficient k = 0.082 m-1 [7]. The P1 approximation method was used to solve the radiative transfer equation (RTE) in spherical coordinates of participating medium confined between two concentric spheres. The surfaces of the spheres are assumed to be gray, diffusely emitting and diffusely reflecting boundaries, and isothermal boundary conditions were assumed at these surfaces. Marsak’s boundary condition was used to compute the net radiative heat flux, q(τ), and the incident radiation, G(τ), to analyze and interpret CVD experiments data that were conducted in the FAST facility at ORNL [8] and Fast Flux Test Facility reactor (FFTF) at ANL. From this study, it can be concluded that there is greater margin of safety when the bubble rise time is a greater than the bubble collapse time since the bubble collapses (UO2 condenses) before it can reach the top of the vessel. In addition, the work transfer by itself can’t completely eliminate the super-heated vapor, as the bubble contains noncondensable species which hinder condensation. However, it is reasonable to assume that work transfer could decrease the amount of UO2 vapor contained in the bubble as it reached the covergas [63].
Hmza Ashur Milad Mohamed, (05-2020), USA: University of Dayton,
An example of industrialization of melt electrospinning: Polymer melt differential electrospinning
Journal ArticleIn recent years, researchers are paying more attention to high efficiency, high process stability and eco-friendly nanofiber fabrication techniques. Among all of the nanofiber fabrication methods, electrospinning including solution electrospinning and melt electrospinning is the most promising method for nanofiber mass production. Compared to solution electrospinning, melt electrospinning could be applied in many areas such as tissue engineering and wound dressings due to the absence of any toxic solvent involvement. Capillary melt electrospinning generates only one jet with low efficiency. Hence, we have proposed polymer melt differential electrospinning (PMDES) method, which could produce multiple jets with smallest interjet distance of 1.1 mm from an umbrella shape spinneret, thus improving the production efficiency significantly. Many techniques such as material modification, suction wind, and …
MAHMOUD M BUBAKIR, (07-2019), Advanced Industrial and Engineering Polymer Research: ELSEVIER, 3 (2), 110-115
أهمية برامج التدريب المطورة والفعالة للعاملين في قطاع التصنيع محليا وعربيا
مقال في مجلة علميةإن العولمة الدولية ألسواق العالم الخاصة بالمواد المصنعة وخاصة منها المواد االستهالكية أو ذات العالقة بالمستهلك وضعت ضغوطات و تأكيدات على الدول من اجل تحسين أو تطوير إنتاجياتها التصنيعية. وكلما تغيرت التقنيات أو طورت فأن المهارات التي يحتاجها العامل أيضا هي بحاجة للتطوير وذلك من أجل المنافسة بنجاح في السوق العالمية. أن الهيئات أو المنظمات الهندسية وغيرها العاملة في مجال التصنيع يجب أن تركز وتستهدف على تدريب العاملين لديها في مهارات أساسية ضرورية وذلك من أجل أن تكون مؤهلة وقادرة على تصنيع منتجات ذات جودة عالية وتنافسية . تلك الحاجة لتحسين وتطوير اإلنتاجية تم تحفيزها أو أستحثاثها أكثر بواسطة فاقد كامن في الحد التنافسي في السوق العالمية. أن المنافسة السوقية والفاعلية ألي دولة تعتمد أساسا على عوامل عدة كاألقتصاد، الموثوقية، الجودة، االستجابة السريعة لتغيرات السوق، سهولة العمليات التصنيعية المتبعة، وجودة المنتج، ولهذا وإلى حد كبير فأن مها ارت قوة العمل من مهندسين، فنيين، وعمالة هي التي تحدد فاعلية وقدرة عمليات التصنيع وجودة المنتجات المصنعة. ولكن وإلى اآلن مازال هناك قصور ونقص في ب ارمج التدريب المطورة والفعالة للمها ارت التي تحتاجها القوى العاملة في المؤسسات التصنيعية الهندسية وغيرها محليا بل وعربيا. في هذه الورقة البحثية سنحاول توضيح أهمية الحاجة الماسة والملحة لتدريب العاملين في المؤسسات التصنيعية الليبية والعربية وبالتالي تحسين الفاعلية والقدرة الكلية لتلك المؤسسات خاصة وللدول العربية بشكل عام لتكون منافس حقيقي وفعال في السوق العالمي.
محمود محمد عاشور ابوبكر، حمزةأبوبكر عمر علي، نورالدين علي فرج الدالي، (06-2019)، مجلة ليبيا للعلوم التطبيقية والتقنية: LJAST، 1 (6)، 15-26