Three postulated initiating events are explored in order to investigate the safety of the reactor of the Tajoura Nuclear Research Reactor with Low Enriched Uranium )LEU). these initiated events are: ramp insertion of a positive reactivity; a reduction of flow of primary coolant (failure of one pump or coast down of two pumps); and a loss of flow accident (LOFA) followed by a reversal flow. PARET computer code is implemented to simulate those suggested initiating events. The transient thermal hydraulic analysis is obtained at both the hottest and averaged cells of the core. the simulation is carried out at different operating power levels of 9.7MW, 9MW, and 5MW. The inlet coolant temperature equals to 45 ° and the average peaking factors are Fxy=2.64 and Fz=1.26. The results exhibit that the worst case of those examined postulated events occurs when the primary coolant flow is reduced due to the collapse of two pumps and the corresponding maximum clad surface temperature reaches to 130.04 °. This assessment assures the safety of the reactor of the TRNC while one of these examined initiating events takes place.

The naphtha cracking process experiences problems such as fouling in the cracked gas compressor, and the accumulation of coke on the furnace coils, which require the use of exhaustive energy resources and costs to maintain the process. Several attempts have been carried out to solve this process in ethylene plants, but reducing fouling and energy costs during naphtha cracking remains a challenge. This study involves a simulation experiment that covers the addition of steam and carbon dioxide to the naphtha cracking process based on realworld data extracted from an ethylene plant in Libya, in order to investigate the effects of the addition of CO2 towards mitigating fouling in the cracked gas compressor, as well as coke accumulation on the coils inside the furnace, and in turn the energy resources and costs involved in the process. The key role of the addition of steam is the fractional elimination of the accumulated coke that leads to various issues within the reactor, such as the low heat transfer and the decrease in pressure. In this study, the diluting media CO2 is employed along with steam in order to investigate its effect on operating conditions and the main products’ yields. Two simulation models were constructed to investigate the thermal cracking process of ethylene in the existence of CO2 and steam. The first model involved only steam, and represented the standard design. The second model involved the addition of both CO2 and steam. After evaluation and comparison of both models, promising results reveal that the addition of CO2 and steam during the naphtha cracking process mitigate costs and energy resources required to …

The importance of flow measurement in the industry has grown in the past 50 year, not just because it was widespread use for accounting purposes, such as custody transfer of fluid from supplier to customers, but also because of its application in manufacturing processes [1,2, and 3], Examples of the industrial involvement in flow measurement includes food and beverage, oil and gas industry, medical, petrochemical, power generation and water distribution, etc. In the research laboratory, advanced flow measurements are providing new insights into a wide range of engineering flow problems in hydrodynamics such as wave impact loading on coastal defenses, beach erosion) combustion such as low Nox burners in IC engines, aerodynamics such as wind turbine optimization and performance prediction) to list but a few [4,5], The aim of this work is to generate an awareness and understanding of the range of contemporary flow measurement techniques available with the emphasis on devices and techniques with wide application in engineering. Focus is devoted to cheap meters with reasonable accuracy; the differential pressure flow meters that all infer the flow rate from a pressure drop across a restriction in the pipe. An orifice plate meter is designed to measure the required flow rate to cool a nuclear reactor at design point is 20 Kg/sec. Meter operation at off design conditions; 5 and 30 Kg/sec minimum and maximum flow rates with maximum allowable orifice pressure drop of 200 KPa were investigated and finalizes the design process.

Because of their persistency and toxicity, dyes and heavy metal ions discharged to water bodies have become a worrisome issue. Therefore, to secure the innate beauty of our planet and to conserve our non-renewable natural resources, specifically, water, it is essential to check and/or to minimize heavy metal ion and dye concentrations before discharge. Adsorption is considered as a robust and widely acclaimed water decontamination technology. In material science research, much attention has been focused on graphene, a carbon allotrope with a two-dimensional sheet-like structure possessing unique structural properties that has been utilized in various research areas. Herein, we present recent developments, specifically focusing on the use of graphene and its derivatives as an adsorbent for dye and heavy metal ion removal from aqueous phase. A historical overview, synthesis methodologies, structural …

This study aimed to investigate how safranin-O can be removed from aqueous solutions by adsorption on pineapple peels. The effect of solution pH, initial dye concentration, contact time and adsorbent dose were studied. The optimum adsorption capacity of 26.08 mg/g was achieved under the experimental condition of pH, temperature and contact time of 6, 293K and 80 min, respectively. Also further analysis revealed that 93.24% of safranin-O was significantly removed at 120 mg/L dye concentration in 80 minutes contact time. From the result of the isotherm studies, it was revealed that the equilibrium data is well fitted to Freundlich model while the adsorption kinetic data showed that the adsorption process was well described by the pseudo-second order kinetic model. Finally, it can be deduced that pineapple peels had a great potential in adsorbing and removal of safranin-o from aqueous solution. 

In this present work, crystalline growth conditions of oriented carbon nanotubes based on chemical vapor deposition (CVD) were optimized. The crystallinity and degree of alignment of the grown carbon nanotubes (CNTs) were characterized by field emission scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The effects of four variables, namely, deposition time, deposition temperature, annealing process, and concentration of the precursor on the crystallinity of the CNTs, were explored. Furthermore, the correlation of parameters with the growth mechanism was examined using response surface methodology in an attempt to determine the complex interactions between the variables. A total of 30 runs, including predicting and consolidation runs to confirm the results, were required for screening the effect of the parameters on the growth of the CNTs. On the basis of the investigated model, it was found that the crystallinity of the CNTs grown by the CVD method can be controlled via restriction of the effective parameters.

Abstract

This paper presents a series of experiments and numerical simulations using commercial software (ANSYS) to determine the behaviour and impact on the blowoff process with various geometries and simulated syngas compositions at fixed power outputs. Experiments were performed using a generic premixed swirl burner. The Central Recirculation Zone and the associated turbulent structure contained within it were obtained through CFD analyses providing details of the structures and the Damkolher Number (Da) close to blowoff limits. The results show how the strength and size of the recirculation zone are highly influenced by the blend, with a shift of Da and turbulence based on carbon-hydrogen ratio, shearing flows and Reynolds number. Instabilities such as thermoacoustics, flashback, autoignition and blowoff are highly affected by the flow structures and chemical reactions/diffusivity. Moreover, it has been observed that turbulence close to the boundaries of the central recirculation zone, a region of high stability for swirling flows, is highly altered by the chemical characteristics of the fuel blends. In terms of blowoff, the phenomenon is still not entirely understood. As the process occurs, its theoretical limits do not match its real behaviour. Therefore, one possibility could be the difference in turbulence and Da numbers across the flame, being critical at the base of the flame where the system is stabilized.