Search results for: radiation flux

Authors: Yu-Ting Chen, Shiao-Shing Chen, Hung-Te Hsu, Saikat Sinha Ray

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Forward osmosis (FO) is a crucial technology with low operating pressure and cost for water reuse and reclamation. In Taiwan, with the advance of science and technology, thin film transistor liquid crystal displays (TFT-LCD) based industries are growing exponentially. In the optoelectronic industry wastewater, the iodide is one of the valuable element; it is also used in the medical industry. In this study, it was intended to concentrate iodide by utilizing FO system and can be reused for TFT-LCD production. Cellulose triacetate (CTA) membranes were used for all these FO experiments, and potassium iodide solution was used as the feed solution. It has been found that EDTA-2Na as draw solution at pH 8 produced high water flux and minimized salt leakage. The result also demonstrated that EDTA-2Na of concentration 0.6M could achieve the highest water flux (6.69L/m2 h). Additionally, from the recovered iodide ion from pH 3-8, the I- species was found to be more than 99%, whereas I2 was measured to be less than 1%. When potassium iodide solution was used from low to high concentration (1000 ppm to 10000 ppm), the iodide rejection was found to be than more 90%. Since, CTA membrane is negatively charged and I- is anionic in nature, so it will from electrostatic repulsion and hence there will be higher rejection. The overall performance demonstrates that recovery of concentrated iodide using FO system is a promising technology.

Keywords: draw solution, EDTA-2Na, forward osmosis, potassium iodide

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Authors: Marjila Burhanzoi, Kenta Onohara, Tomoaki Ikegami

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Faults in photovoltaic (PV) modules should be detected to the greatest extent as early as possible. For that conventional fault detection methods such as electrical characterization, visual inspection, infrared (IR) imaging, ultraviolet fluorescence and electroluminescence (EL) imaging are used, but they either fail to detect the location or category of fault, or they require expensive equipment and are not convenient for onsite application. Hence, these methods are not convenient to use for monitoring small-scale PV systems. Therefore, low cost and efficient inspection techniques with the ability of onsite application are indispensable for PV modules. In this study in order to establish efficient inspection technique, correlation between faults and magnetic flux density on the surface is of crystalline PV modules are investigated. Magnetic flux on the surface of normal and faulted PV modules is measured under the short circuit and illuminated conditions using two different sensor devices. One device is made of small integrated sensors namely 9-axis motion tracking sensor with a 3-axis electronic compass embedded, an IR temperature sensor, an optical laser position sensor and a microcontroller. This device measures the X, Y and Z components of the magnetic flux density (Bx, By and Bz) few mm above the surface of a PV module and outputs the data as line graphs in LabVIEW program. The second device is made of a laser optical sensor and two magnetic line sensor modules consisting 16 pieces of magnetic sensors. This device scans the magnetic field on the surface of PV module and outputs the data as a 3D surface plot of the magnetic flux intensity in a LabVIEW program. A PC equipped with LabVIEW software is used for data acquisition and analysis for both devices. To show the effectiveness of this method, measured results are compared to those of a normal reference module and their EL images. Through the experiments it was confirmed that the magnetic field in the faulted areas have different profiles which can be clearly identified in the measured plots. Measurement results showed a perfect correlation with the EL images and using position sensors it identified the exact location of faults. This method was applied on different modules and various faults were detected using it. The proposed method owns the ability of on-site measurement and real-time diagnosis. Since simple sensors are used to make the device, it is low cost and convenient to be sued by small-scale or residential PV system owners.

Keywords: fault diagnosis, fault location, integrated sensors, PV modules

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Authors: Calvince Okome Odeny

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There is a current action to increase radiotherapy services in Kenya. The National government of Kenya, in collaboration with the county governments, has embarked on building radiotherapy centers in all 47 regions of the country. As these new centers are established in Kenya, it has to be ensured that minimum radiation safety standards are in place prior to operation. For full implementation of this, it is imperative that more Research and training for regulators are done on radiation protection, and safety and national regulatory infrastructure is geared towards ensuring radiation protection and safety in all aspects of the use of external radiotherapy practices. The present work aims at reviewing the level of protection and safety for patients and staff during external beam radiotherapy using Linac in Kenya and provides relevant guidance to improve protection and safety. A retrospective evaluation was done to verify whether those occupationally exposed workers and patients are adequately protected from the harmful effect of radiation exposure during the treatment procedures using Linac. The project was experimental Research, also including an analysis of resource documents obtained from the literature and international organizations. The critical findings of the work revealed that the key elements of protection of occupationally exposed workers and patients include a comprehensive quality Management system governing all planned activities from siting, safety, and design of the Facility, construction, acceptance testing, commissioning, operation, and decommissioning of the Facility; Government empowering the Regulatory Authority to license Medical Linear facilities and to enforce the applicable regulations to ensure adequate protection; A comprehensive Radiation Protection and Safety program must be established to ensure adequate safety and protection of workers and patients during treatment planning and treatment delivery of patients and categories of staff associated with the Facility must be well educated and trained to perform professionally with a commitment to sound safety culture. Relevant recommendations from the findings are shared with the Medical Linear Accelerator facilities and the regulatory authority to provide guidance and continuous improvement of protection and safety to improve regulatory oversight.

Keywords: oncology, radiotherapy, protection, staff

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Authors: G. H. Haddadi, S. Sajadi, R. Fardid, Z. Haddadi

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The heart is a radiosensitive organ, and its damage is a dose-limiting factor in radiotherapy. Different side effects including vascular plaque and heart fibrosis occur in patients with thorax irradiation. The present study aimed to evaluate the radioprotective efficacy of Hesperidin (HES), a naturally occurring citrus flavanoglycone, against γ-radiation induced tissue damage in the heart of male rats. Sixty-eight rats were divided into four groups. The rats in group 1 received PBS, and those in group 2 received HES. Also, the rats in group 3 received PBS and underwent γ-irradiation, and those in group 4 received HES and underwent γ-irradiation. They were exposed to 20 Gy γ-radiation using a single fraction cobalt-60 unit, and the dose of Hesperidin was (100 mg/kg/d, orally) for 7 days prior irradiation. Each group was divided into two subgroups. Samplings of rats in subgroup A was done 4-6 hours after irradiation. The samples were sent to laboratory for determination of Troponin’s I (TnI) serum level changes as a cardiac biomarker. The remaining animals (subgroups B) were sacrificed 8 weeks after radiotherapy for histopathological evaluation. In group 3, TnI obviously increased in comparison with group 1 (p < 0.05). The comparison of groups 1 and 4 showed no significant difference. Evaluation of histopathological parameters in subgroup B showed significant differences between groups 1 and 3 in some of the cases. Inflammation (p=0.008), pericardial effusion (p=0.001) and vascular plaque (p=0.001) increased in the rats exposed to 20 Gy γ-irradiation. Using oral administration of HES significantly decreased all the above factors when compared to group 4 (P > 0.016). Administration of 100 mg/kg/day Hesperidin for 7 days resulted in decreased Troponin I and radiation heart injury. This agent may have protective effects against radiation-induced heart damage.

Keywords: hesperidin, radioprotector, troponin I, cardiac inflammation, vascular plaque

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Authors: Dnyandip K. Bhamare, Manish K Rathod, Jyotirmay Banerjee

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This paper aims to study performance of a thermosiphon solar water heating system with the help of the proposed analytical model. This proposed model predicts the temperature and mass flow rate in a thermosiphon solar water heating system depending on radiation intensity and ambient temperature. The performance of the thermosiphon solar water heating system is evaluated in the Indian context. For this, eight cities in India are selected considering radiation intensity and geographical positions. Predicted performance at various cities reveals the potential for thermosiphon solar water in India.

Keywords: solar water heater, collector outlet temperature, thermosyphon, India

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Authors: Jianhua Zhou, Yuwen Zhang

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A two-step multigrid approach is proposed to solve the inverse heat conduction problem in a 3-D object under laser irradiation. In the first step, the location of the laser center is estimated using a coarse and uniform grid system. In the second step, the front-surface temperature is recovered in good accuracy using a multiple grid system in which fine mesh is used at laser spot center to capture the drastic temperature rise in this region but coarse mesh is employed in the peripheral region to reduce the total number of sensors required. The effectiveness of the two-step approach and the multiple grid system are demonstrated by the illustrative inverse solutions. If the measurement data for the temperature and heat flux on the back surface do not contain random error, the proposed multigrid approach can yield more accurate inverse solutions. When the back-surface measurement data contain random noise, accurate inverse solutions cannot be obtained if both temperature and heat flux are measured on the back surface.

Keywords: conduction, inverse problems, conjugated gradient method, laser

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Authors: Brady Manescau, Ilyas Sellami, Khaled Chetehouna, Charles De Izarra, Rachid Nait-Said, Fati Zidani

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During a fire in an oil and gas refinery, several thermal accidents can occur and cause serious damage to people and environment. Among these accidents, the BLEVE (Boiling Liquid Expanding Vapor Explosion) is most observed and remains a major concern for risk decision-makers. It corresponds to a violent vaporization of explosive nature following the rupture of a vessel containing a liquid at a temperature significantly higher than its normal boiling point at atmospheric pressure. Their effects on the environment generally appear in three ways: blast overpressure, radiation from the fireball if the liquid involved is flammable and fragment hazards. In order to estimate the potential damage that would be caused by such an explosion, risk decision-makers often use quantitative risk analysis (QRA). This analysis is a rigorous and advanced approach that requires a reliable data in order to obtain a good estimate and control of risks. However, in most cases, the data used in QRA are obtained from the empirical correlations. These empirical correlations generally overestimate BLEVE effects because they are based on simplifications and do not take into account real parameters like the geometry effect. Considering that these risk analyses are based on an assessment of BLEVE effects on human life and plant equipment, more precise and reliable data should be provided. From this point of view, the CFD modeling of BLEVE effects appears as a solution to the empirical law limitations. In this context, the main objective is to develop a numerical tool in order to predict BLEVE thermal effects using the CFD code FDS version 6. Simulations are carried out with a mesh size of 1 m. The fireball source is modeled as a vertical release of hot fuel in a short time. The modeling of fireball dynamics is based on a single step combustion using an EDC model coupled with the default LES turbulence model. Fireball characteristics (diameter, height, heat flux and lifetime) issued from the large scale BAM experiment are used to demonstrate the ability of FDS to simulate the various steps of the BLEVE phenomenon from ignition up to total burnout. The influence of release parameters such as the injection rate and the radiative fraction on the fireball heat flux is also presented. Predictions are very encouraging and show good agreement in comparison with BAM experiment data. In addition, a numerical study is carried out on an operational propane accumulator in an Algerian gas processing plant of SONATRACH company located in the Hassi R’Mel Gas Field (the largest gas field in Algeria).

Keywords: BLEVE effects, CFD, FDS, fireball, LES, QRA

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Authors: B. Adebayo, A. A. Adebayo

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Adequate power generation and supply are enormous challenges confronting Nigeria state today. This is a powerful mechanism that drives industrial development and socio-economy of any nation. The present level of power generation and supply have become national embarrassment to both government and the citizens of Nigeria, where over 60% of the population have no access to electricity. This paper is set to review the abundant clean energy alternative sources available in abundance that are capable of boosting power generation. The clean energy sources waiting to be exploited include: nuclear, solar and wind energy. The environmental benefits of these sources of power generation are identified. Nuclear energy is a powerful clean energy source. However, Africa accounted for 20% of known recoverable reserve and uranium produces heat of 500,000 MJ/kg. Moreover, Nigeria receives average daily solar radiation of over 5.249 kWh/m2/day. Researchers have shown that wind speed and power flux densities varied from 1.5 – 4.1 m/s and 5.7 – 22.5 W/m2 respectively. It is a fact that the cost of doing business in Nigeria is very high, leading to winding up of the multi-national companies and then led to increase unemployment level. More importantly, readily available vast quantity of energy will reduce cost of running industries. Hence, more industries will come on board, goods, services, and more job creation will be achieved. This clean source of power generation is devoid of production of green house gases, elimination of environmental pollution, and reduced waste disposal. Then Nigerians will live in harmony with the environment.

Keywords: power, generation, energy, mix, clean, industrial

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Authors: S. Abeysekera, M. Bazghaleh, M. P. L. Ooi, Y. C. Kuang, V. Kalavally

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Smart LED-based lighting systems have significant advantages over traditional lighting systems due to their capability of producing tunable light spectrums on demand. The main challenge in the design of smart lighting systems is to produce sufficient luminous flux and uniformly accurate output spectrum for sufficiently broad area. This paper outlines the programmable LED lighting system design principles of design to achieve the two aims. In this paper, a seven-channel design using low-cost discrete LEDs is presented. Optimization algorithms are used to calculate the number of required LEDs, LEDs arrangements and optimum LED separation distance. The results show the illumination uniformity for each channel. The results also show that the maximum color error is below 0.0808 on the CIE1976 chromaticity scale. In conclusion, this paper considered the simulation and design of a seven-channel programmable lighting system using low-cost discrete LEDs to produce sufficient luminous flux and uniformly accurate output spectrum for sufficiently broad area.

Keywords: light spectrum control, LEDs, smart lighting, programmable LED lighting system

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Authors: Manpreet Kaur

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The effect of external and internal exposure in outdoor and indoor environment can be significantly gauged by natural radionuclides. Therefore, it is a consequential to approximate the level of radionuclide contents in soil samples of any area and the risks associated with it. Rate of radon emerging from soil is also one of the prominent parameters for the assessment of radon levels in environmental. In present study, natural radionuclide contents viz. ²³²Th, ²³⁸U and ⁴⁰K and radon/thoron exhalation rates were evaluated operating thallium doped sodium iodide gamma radiation detector and advanced Smart Rn Duo technique in the soil samples from 30 villages of Jammu district, Jammu and Kashmir, India. Radon flux rate was also measured by using surface chamber technique. Results obtained with two different methods were compared to investigate the cause of emanation factor in the soil profile. The radon mass exhalation rate in the soil samples has been found varying from 15 ± 0.4 to 38 ± 0.8 mBq kg⁻¹ h⁻¹ while thoron surface exhalation rate has been found varying from 90 ± 22 to 4880 ± 280 Bq m⁻² h⁻¹. The mean value of radium equivalent activity (99 ± 27 Bq kg⁻¹) was appeared to be well within the admissible limit of 370 Bq kg⁻¹ suggested by Organization for Economic Cooperation and Development (2009) report. The values of various parameters related to radiological hazards were also calculated and all parameters have been found to be well below the safe limits given by various organizations. The outcomes pointed out that region was protected from danger as per health risks effects associated with these radionuclide contents is concerned.

Keywords: absorbed dose rate, exhalation rate, human health, radionuclide

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Authors: Kaouther Bergaui, Nafaa Reguigui, Charles Gary

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Characterization and the applications of deuterium-deuterium (DD) neutron generator developed by Adelphie technology and acquired by the National Centre of Nuclear Science and Technology (NCNST) were presented in this work. We study the performance of the neutron generator in terms of neutron yield, production efficiency, and the ionic current as a function of the acceleration voltage at various RF powers. We provide the design and optimization of the PGNAA chamber and thus give insight into the capabilities of the planned PGNAA facility. Additional non-destructive techniques were studied employing the DD neutron generator, such as PGNAA and neutron radiography: The PGNAA is used for determining the concentration of 10B in Si and SiO2 matrices by using a germanium detector HPGe and the results obtained are compared with PGNAA system using a Sodium Iodide detector (NaI (Tl)); Neutron radiography facility was tested and simulated, using a camera device CCD and simulated by the Monte Carlo code; and the explosive detection system (EDS) also simulated using the Monte Carlo code. The study allows us to show that the new models of DD neutron generators are feasible and that superior-quality neutron beams could be produced and used for various applications. The feasibility of Boron neutron capture therapy (BNCT) for cancer treatment using a neutron generator was assessed by optimizing Beam Shaping Assembly (BSA) on a phantom using Monte-Carlo (MCNP6) simulations.

Keywords: neutron generator deuterium-deuterium, Monte Carlo method, radiation, neutron flux, neutron activation analysis, born, neutron radiography, explosive detection, BNCT

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Authors: Ibrahim Al-Suraihy, Abdellaziz Doghmane, Zahia Hadjoub

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We discuss in this work the elastic properties by using acoustic microscopes to measure Rayleigh and longitudinal wave velocities in a no radiated and radiated sodium borate glasses X2Na2O-X2B2O3 with 0 ≤ x ≤ 27 (mol %) at microscopic resolution. The acoustic material signatures were first measured, from which the characteristic surface velocities were determined.Longitudinal and shear ultrasonic velocities were measured in a different composition of sodium borate glass samples before and after irradiation with γ-rays. Results showed that the effect due to increasing sodium oxide content on the ultrasonic velocity appeared more clearly than due to γ-radiation. It was found that as Na2O composition increases, longitudinal velocities vary from 3832 to 5636 m/s in irradiated sample and it vary from 4010 to 5836 m/s in high radiated sample by 10 dose whereas shear velocities vary from 2223 to 3269 m/s in irradiated sample and it vary from 2326 m/s in low radiation to 3385 m/s in high radiated sample by 10 dose. The effect of increasing sodium oxide content on ultrasonic velocity was very clear. The increase of velocity was attributed to the gradual increase in the rigidity of glass and hence strengthening of network due to gradual change of boron atoms from the three-fold to the four-fold coordination of oxygen atoms. The ultrasonic velocities data of glass samples have been used to find the elastic modulus. It was found that ultrasonic velocity, elastic modulus and microhardness increase with increasing barium oxide content and increasing γ-radiation dose.

Keywords: mechanical properties X2Na2O-X2B2O3, acoustic signature, SAW velocities, additives, gamma-radiation dose

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Authors: Sofiane Bourchak, Sébastien Bridier

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The objective of this study is to show how to calculate and map solar energy’s quantity (instantaneous and accumulated global solar radiation during the year) available on roofs in the city Aix-en-Provence which has a population of 140,000 inhabitants. The result is a geographic information system (GIS) layer, which represents hourly and monthly the production of solar energy on roofs throughout the year. Solar energy professionals can use it to optimize implementations and to size energy production systems. The results are presented as a set of maps, tables and histograms in order to determine the most effective costs in Aix-en-Provence in terms of photovoltaic power (electricity) and thermal power (hot water).

Keywords: geographic information system, photovoltaic, thermal, solar potential, solar radiation

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Authors: Daniel Osorio, Janneth Gonzalez, Andres Pinzon

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In this work, proteins and metabolic pathways associated with the neuroprotective response mediated by the synthetic neurosteroid tibolone under a palmitate-induced inflammatory model were identified by flux balance analysis (FBA). Three different metabolic scenarios (‘healthy’, ‘inflamed’ and ‘medicated’) were modeled over a gene expression data-driven constructed tissue-specific metabolic reconstruction of mature astrocytes. Astrocyte reconstruction was built, validated and constrained using three open source software packages (‘minval’, ‘g2f’ and ‘exp2flux’) released through the Comprehensive R Archive Network repositories during the development of this work. From our analysis, we predict that tibolone executes their neuroprotective effects through a reduction of neurotoxicity mediated by L-glutamate in astrocytes, inducing the activation several metabolic pathways with neuroprotective actions associated such as taurine metabolism, gluconeogenesis, calcium and the Peroxisome Proliferator Activated Receptor signaling pathways. Also, we found a tibolone associated increase in growth rate probably in concordance with previously reported side effects of steroid compounds in other human cell types.

Keywords: astrocytes, flux balance analysis, genome scale metabolic reconstruction, inflammation, neuroprotection, tibolone

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Authors: R. Nasrin, M. Ferdows

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Among the renewable energy sources, photovoltaic (PV) is a high potential, effective, and sustainable system. Irradiation intensity from 200 W/m2 to 1000 W/m2 has been considered to observe the performance of PV module. Generally, this module converts only about 15% - 20% of incident irradiation into electrical energy and the rest part is converted into heat energy. Finite element method has been used to solve the problem numerically. Simulation has been performed by considering the ambient temperature 30°C. Higher irradiation increase solar cell temperature and electrical power. The electrical efficiency of PV module decreases with the variation of solar radiation. The efficiency of PV module can be increased if cell temperature is reduced. Thus the effect of irradiation is significant to enhance the efficiency of PV module if the solar cell temperature is kept at a certain level.

Keywords: PV module, solar radiation, efficiency, cell temperature

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Authors: Aminu Yakubu Umar

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X-ray is the major contributor to the effective dose of both the patient and the personnel. Because of the radiological risks involved, it is usually recommended that dose to patient from X-ray be kept as low as reasonably achievable (ALARA) with adequate image quality. The implementation of quality assurance in diagnostic radiology can help greatly in achieving that, as it is a technique designed to reduce X-ray doses to patients undergoing radiological examination. In this study, quality control was carried out in six hospitals, which involved KVp test, evaluation of total filtration, test for constancy of radiation output, and check for mA linearity. Equipment used include KVp meter, Rad-check meter, aluminum sheets (0.1–1.0 mm) etc. The results of this study indicate that, the age of the X-ray machines in the hospitals ranges from 3-13 years, GHI and GH2 being the oldest and FMC being the newest. In the evaluation of total filtration, the HVL of the X-ray machines in the hospitals varied, ranging from 2.3-5.2 mm. The HVL was found to be highest in AHC (5.2 mm), while it was lowest in GH3 (2.3 mm). All HVL measurements were done at 80 KVp. The variation in voltage accuracy in the hospitals ranges from 0.3%-127.5%. It was only in GH1 that the % variation was below the allowed limit. The test for constancy of radiation output showed that, the coefficient of variation ranges from 0.005–0.550. In GH3, FMC and AHC, the coefficient of linearity were less than the allowed limit, while in GH1, GH2 and GH4 the coefficient of linearity had exceeded the allowed limit. As regard to mA linearity, FMC and AHC had their coefficients of linearity as 0.12 and 0.10 respectively, which were within the accepted limit, while GH1, GH3 and GH4 had their coefficients as 0.16, 0.69 and 0.98 respectively, which exceeded the allowed limit.

Keywords: radiation, X-ray output, quality control, half-value layer, mA linearity, KVp variation

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Authors: A. Evcin, N. Çiçek Bezir, R. Duman, N. Duman

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Nowadays, a great concern is placed on the harmfulness of ultraviolet radiation (UVR) which attacks human bodies. Nanocarbon materials, such as carbon nanotubes (CNTs), carbon nanofibers (CNFs) and graphene, have been considered promising alternatives to shielding materials because of their excellent electrical conductivities, very high surface areas and low densities. In the present work, carbon nanofibers have been synthesized from solutions of Polyacrylonitrile (PAN)/ N,N-dimethylformamide (DMF) by electrospinning method. The carbon nanofibers have been stabilized by oxidation at 250 °C for 2 h in air and carbonized at 750 °C for 1 h in H2/N2. We present the fabrication and characterization of transparent and ultraviolet (UV) shielding CNF/polymer composites. The content of CNF filler has been varied from 0.2% to 0.6 % by weight. UV Spectroscopy has been performed to study the effect of composition on the transmittance of polymer composites.

Keywords: electrospinning, carbon nanofiber, characterization, composites, nanofiber, ultraviolet radiation

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Authors: Hussam Elias, Ninovic Perez, Holger Hirsch

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The completion of the EMC regulations worldwide is growing steadily as the usage of electronics in our daily lives is increasing more than ever. In this paper, we introduce a novel method to perform the final phase of Electromagnetic compatibility (EMC) measurement and to reduce the required test time according to the norm EN 55032 by using a developed tool and the conventional neural network(CNN). The neural network was trained using real EMC measurements, which were performed in the Semi Anechoic Chamber (SAC) by CETECOM GmbH in Essen, Germany. To implement our proposed method, we wrote software to perform the radiated electromagnetic interference (EMI) measurements and use the CNN to predict and determine the position of the turntable that meets the maximum radiation value.

Keywords: conventional neural network, electromagnetic compatibility measurement, mean absolute error, position error

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Authors: H. T. Abba, Abbas Baba Kura

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Assessment of natural radioactivity of some fish samples in river Yobe was conducted, using gamma spectroscopy method with NaI(TI) detector. Radioactivity is phenomenon that leads to production of radiations, whereas radiation is known to trigger or induce cancer. The fish were analyzed to estimate the radioactivity (activity) concentrations due to natural radionuclides (Radium 222(226Ra), Thorium 232 (232Th) and Potassium 40 (40K)). The obtained result show that the activity concentration for (226Ra), in all the fish samples collected ranges from 15.23±2.45 BqKg-1 to 67.39±2.13 BqKg-1 with an average value of 34.13±1.34 BqKg-1. That of 232Th, ranges from 42.66±0.81 BqKg-1 to 201.18±3.82 BqKg-1, and the average value stands at 96.01±3.82 BqKg-1. The activity concentration for 40K, ranges between 243.3±1.56 BqKg-1 to 618.2±2.81 BqKg-1 and the average is 413.92±1.7 BqKg-1. This study indicated that average daily intake due to natural activity from the fish is valued at 0.913 Bq/day, 2.577Bq/day and 11.088 Bq/day for 226Ra, 232Th and 40K respectively. This shows that the activity concentration values for fish, shows a promising result with most of the fish activity concentrations been within the acceptable limits. However locations (F02, F07 and F12) fish, became outliers with significant values of 112.53μSvy-1, 121.11μSvy-1 and 114.32μSvy-1 effective Dose. This could be attributed to variation in geological formations within the river as while as the feeding habits of these fish. The work shows that consumers of fish from River Yobe have no risk of radioactivity ingestion, even though no amount of radiation is assumed to be totally safe.

Keywords: radiation, radio-activity, dose, radionuclides, river Yobe

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Authors: F. Abbas Pour Khotbehsara, B. Salehpour, A. Kianvash

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Many industrial materials like magnets need to be tested for the radiation environment expected at linear colliders (LC) where the accelerator and detectors will be subjected to large influences of beta, neutron and gamma’s over their life Gamma irradiation of the permanent sample magnets using a 60Co source was investigated up to an absorbed dose of 700Mrad shows a negligible effect on some magnetic properties of Nd-Fe-B. In this work, it has been tried to investigate the change of some important properties of Barium hexa ferrite. Results showed little decreases of magnetic properties at doses rang of 0.5 to 2.5 Mrad. But at the gamma irradiation dose up to 10 Mrad it is showed a few increase of properties. Also study of gamma irradiation of Nd-Fe-B showed considerably increase of magnetic properties.

Keywords: gamma ray irradiation, hard ferrite, magnetic coefficient, magnetic material, radiation dose

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Authors: Binyam Teferi

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Numerical and theoretical analysis of mixed convection flow of magneto- hydrodynamics micropolar fluid with stretching capillary in the presence of thermal radiation, chemical reaction, viscous dissipation, and heat generation/ absorption have been studied. The non-linear partial differential equations of momentum, angular velocity, energy, and concentration are converted into ordinary differential equations using similarity transformations which can be solved numerically. The dimensionless governing equations are solved by using Runge Kutta fourth and fifth order along with the shooting method. The effect of physical parameters viz., micropolar parameter, unsteadiness parameter, thermal buoyancy parameter, concentration buoyancy parameter, Hartmann number, spin gradient viscosity parameter, microinertial density parameter, thermal radiation parameter, Prandtl number, Eckert number, heat generation or absorption parameter, Schmidt number and chemical reaction parameter on flow variables viz., the velocity of the micropolar fluid, microrotation, temperature, and concentration has been analyzed and discussed graphically. MATLAB code is used to analyze numerical and theoretical facts. From the simulation study, it can be concluded that an increment of micropolar parameter, Hartmann number, unsteadiness parameter, thermal and concentration buoyancy parameter results in decrement of velocity flow of micropolar fluid; microrotation of micropolar fluid decreases with an increment of micropolar parameter, unsteadiness parameter, microinertial density parameter, and spin gradient viscosity parameter; temperature profile of micropolar fluid decreases with an increment of thermal radiation parameter, Prandtl number, micropolar parameter, unsteadiness parameter, heat absorption, and viscous dissipation parameter; concentration of micropolar fluid decreases as unsteadiness parameter, Schmidt number and chemical reaction parameter increases. Furthermore, computational values of local skin friction coefficient, local wall coupled coefficient, local Nusselt number, and local Sherwood number for different values of parameters have been investigated. In this paper, the following important results are obtained; An increment of micropolar parameter and Hartmann number results in a decrement of velocity flow of micropolar fluid. Microrotation decreases with an increment of the microinertial density parameter. Temperature decreases with an increasing value of the thermal radiation parameter and viscous dissipation parameter. Concentration decreases as the values of Schmidt number and chemical reaction parameter increases. The coefficient of local skin friction is enhanced with an increase in values of both the unsteadiness parameter and micropolar parameter. Increasing values of unsteadiness parameter and micropolar parameter results in an increment of the local couple stress. An increment of values of unsteadiness parameter and thermal radiation parameter results in an increment of the rate of heat transfer. As the values of Schmidt number and unsteadiness parameter increases, Sherwood number decreases.

Keywords: thermal radiation, chemical reaction, viscous dissipation, heat absorption/ generation, similarity transformation

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Authors: Ari S. Prabowo, Nia Febriyanti, Haryono B. Santosa

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Security function that is called as Physical Protection Systems (PPS) has functions to detect, delay and response. Physical Protection Systems (PPS) in Detection and Radiation Measurement Laboratory needs to be improved continually by using internal resources. The nuclear security culture provides some potentials to support this research. The study starts by identifying the security function’s weaknesses and its strengths of security culture as a purpose. Secondly, the strengths of security culture are implemented in the laboratory management. Finally, a simulation was done to measure its effectiveness. Some changes were happened in laboratory personnel behaviors and procedures. All became more prudent. The results showed a good influence of nuclear security culture in laboratory security functions.

Keywords: laboratory, physical protection system, security culture, security function

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Authors: J. R. Wang, H. C. Chen, C. Shih, S. W. Chen, J. H. Yang, Y. Chiang

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In this study, we focus on the establishment of the analysis model for Maanshan PWR nuclear power plant (NPP) by using RADTRAD and SNAP codes with the FSAR, manuals, and other data. In order to evaluate the cumulative dose at the Exclusion Area Boundary (EAB) and Low Population Zone (LPZ) outer boundary, Maanshan NPP RADTRAD/SNAP model was used to perform the analysis of the DBA LOCA case. The analysis results of RADTRAD were similar to FSAR data. These analysis results were lower than the failure criteria of 10 CFR 100.11 (a total radiation dose to the whole body, 250 mSv; a total radiation dose to the thyroid from iodine exposure, 3000 mSv).

Keywords: RADionuclide, transport, removal, and dose estimation (RADTRAD), symbolic nuclear analysis package (SNAP), dose, PWR

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Authors: Zoliana Bawitlung, P. C. Rohmingliana, L. Z. Chhangte, Remlal Siama, Hming Chungnunga, Vanram Lawma, L. Hnamte, B. K. Sahoo, B. K. Sapra, J. Malsawma

Abstract:

Mizoram state has the highest lung cancer incidence rate in India due to its high-level consumption of tobacco and its products which is supplemented by the food habits. While smoking is mainly responsible for this incidence, the effect of inhalation of indoor radon gas cannot be discarded as the hazardous nature of this radioactive gas and its progenies on human population have been well-established worldwide where the radiation damage to bronchial cells eventually can be the second leading cause of lung cancer next to smoking. It is also known that the effect of radiation, however, small may be the concentration, cannot be neglected as they can bring about the risk of cancer incidence. Hence, estimation of indoor radon concentration is important to give a useful reference against radiation effects as well as establishing its safety measures and to create a baseline for further case-control studies. The indoor radon/thoron concentrations in Mizoram had been measured in 41 dwellings selected on the basis of spot gamma background radiation and construction type of the houses during 2015-2016. The dwellings were monitored for one year, in 4 months cycles to indicate seasonal variations, for the indoor concentration of radon gas and its progenies, outdoor gamma dose, and indoor gamma dose respectively. A time-integrated method using Solid State Nuclear Track Detector (SSNTD) based single entry pin-hole dosimeters were used for measurement of indoor Radon/Thoron concentration. Gamma dose measurements for indoor as well as outdoor were carried out using Geiger Muller survey meters. Seasonal variation of indoor radon/ thoron concentration was monitored. The results show that the annual average radon concentrations varied from 54.07 – 144.72 Bq/m³ with an average of 90.20 Bq/m³ and the annual average thoron concentration varied from 17.39 – 54.19 Bq/m³ with an average of 35.91 Bq/m³ which are below the permissible limit. The spot survey of gamma background radiation level varies between 9 to 24 µR/h inside and outside the dwellings throughout Mizoram which are all within acceptable limits. From the above results, there is no direct indication that radon/thoron is responsible for the high lung cancer incidence in the area. In order to find epidemiological evidence of natural radiations to high cancer incidence in the area, one may need to conduct a case-control study which is beyond this scope. However, the derived data of measurement will provide baseline data for further studies.

Keywords: background gamma radiation, indoor radon/thoron, lung cancer, seasonal variation

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Authors: Jay J. Vora, Vishvesh J. Badheka

Abstract:

This work attempts to investigate the effect of oxide fluxes on 6mm thick Reduced Activation ferritic/martensitic steels (RAFM) during Activated TIG (A-TIG) welding. Six different fluxes Al₂O₃, Co₃O₄, CuO, HgO, MoO₃, and NiO were mixed with methanol for conversion into paste and bead-on-plate experiments were then carried out. This study, systematically investigates the influence of oxide-based flux powder and carrier solvent composition on the weld bead shape, geometric shape of weld bead and dominant depth enhancing mechanism in tungsten inert gas (TIG) welding of reduced activation ferritic/martensitic (RAFM) steel. It was inferred from the study that flux Co₃O₄ and MoO₃ imparted full and secure (more than 6mm) penetration with methanol owing to dual mechanism of reversed Marangoni and arc construction. The use of methanol imparted good spreadabilty and coverability and ultimately higher peak temperatures were observed with its use owing to stronger depth enhancing mechanisms than use of acetone with same oxide fluxes and welding conditions.

Keywords: A-TIG, flux, oxides, penetration, RAFM, temperature, welding

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Authors: Arkadiusz Urzędowski, Dorota Wójcicka-Migasiuk, Andrzej Sachajdak, Magdalena Paśnikowska-Łukaszuk

Abstract:

Due to the impact of climate changes and inevitability to reduce greenhouse gases, the need to use low-carbon and sustainable construction has increased. In this work, it is investigated how texture of the surface building materials and radiative heat transfer phenomenon in flat multilayer can be correlated. Attempts to test the surface emissivity are taken however, the trustworthiness of measurement results remains a concern since sensor size and thickness are common problems. This paper presents an experimental method to studies surface emissivity with use self constructed thermal sensors and thermal imaging technique. The surface of building materials was modified by mechanical and chemical treatment affecting the reduction of the emissivity. For testing the shaping surface of materials and mapping its three-dimensional structure, scanning profilometry were used in a laboratory. By comparing the results of laboratory tests and performed analysis of 3D computer fluid dynamics software, it can be shown that a change in the surface coverage of materials affects the heat transport by radiation between layers. Motivated by recent advancements in variational inference, this publication evaluates the potential use a dedicated data processing approach, and properly constructed temperature sensors, the influence of the surface emissivity on the phenomenon of radiation and heat transport in the entire partition can be determined.

Keywords: heat transfer, surface roughness, surface emissivity, radiation

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Authors: Ananta R. Adhikari

Abstract:

In today's era, polymer composite utilization has witnessed a significant increase across various fronts of material science advancement. Despite the development of many highly sophisticated technologies aimed at modifying polymer composites, there persists a quest for a technology that is straightforward, energy-efficient, easily controllable, cost-effective, time-saving, and environmentally friendly. Microwave technology has emerged as a major technique in material synthesis and modification due to its unique characteristics such as rapid, selective, uniform heating, and, particularly, direct heating based on molecular interaction. This study will be about the utilization of microwave energy as an alternative technique for material processing. Specifically, we will explore ongoing research conducted in our laboratory, focusing on its applications in the medical field.

Keywords: polymer composites, material processing, microstructure, microwave radiation

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Authors: Óscar Alfonso Gómez Sepúlveda, Julián Ernesto Jaramillo, Diego Camilo Durán

Abstract:

The global climate crisis has affected different aspects of human life, and in an effort to reverse the effects generated, we seek to optimize and improve the equipment and plants that produce high emissions of CO₂, being possible to achieve this through numerical simulations. These equipments include biomass combustion chambers. The objective of this research is to visualize the thermal behavior of a gas chamber that is used in the process of obtaining vegetable extracts. The simulation is carried out with OpenFOAM taking into account the conservation of energy, turbulence, and radiation; for the purposes of the simulation, combustion is omitted and replaced by heat generation. Within the results, the streamlines generated by the primary and secondary flows are analyzed in order to visualize whether they generate the expected effect, and the energy is used to the maximum. The inclusion of radiation seeks to compare its influence and also simplify the computational times to perform mesh analysis. An analysis is carried out with simplified geometries and with experimental data to corroborate the selection of the models to be used, and it is obtained that for turbulence, the appropriate one is the standard k - w. As a means of verification, a general energy balance is made and compared with the results of the numerical analysis, where the error is 1.67%, which is considered acceptable. From the approach to improvement options, it was found that with the implementation of fins, heat can be increased by up to 7.3%.

Keywords: CFD analysis, biomass, heat transfer, radiation, OpenFOAM

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Authors: Sergei Voychuk

Abstract:

Introduction: Adaptive response (AR) is a manifestation of radiation hormesis, which deal with the radiation resistance that may be increased with the pretreatment with small doses of radiation. In the current study, we evaluated the potency of radiofrequency EMF to induce the AR mechanisms and to increase a resistance to UV light. Methods: Saccharomyces cerevisiae yeast strains, which were created to study induction of mutagenesis and recombination, were used in the study. The strains have mutations in rad2 and rad54 genes, responsible for DNA repair: nucleotide excision repair (PG-61), postreplication repair (PG-80) and mitotic (crossover) recombination (T2). An induction of mutation and recombination are revealed due to the formation of red colonies on agar plates. The PG-61 and T2 are UV sensitive strains, while PG-80 is sensitive to ionizing radiation. Extremely high frequency electromagnetic field (EHF-EMF) was used. The irradiation was performed in floating mode and frequency changed during exposure from 57 GHz to 62 GHz. The power of irradiation was 100 mkW, and duration of exposure was 10 and 30 min. Treatment was performed at RT and then cells were stored at 28° C during 1 h without any exposure but after that they were treated with UV light (254nm) for 20 sec (strain T2) and 120 sec (strain PG-61 and PG-80). Cell viability and quantity of red colonies were determined after 5 days of cultivation on agar plates. Results: It was determined that EHF-EMF caused 10-20% decrease of viability of T2 and PG-61 strains, while UV showed twice stronger effect (30-70%). EHF-EMF pretreatment increased T2 resistance to UV, and decreased it in PG-61. The PG-80 strain was insensitive to EHF-EMF and no AR effect was determined for this strain. It was not marked any induction of red colonies formation in T2 and PG-80 strain after EHF or UV exposure. The quantity of red colonies was 2 times more in PG-61 strain after EHF-EMF treatment and at least 300 times more after UV exposure. The pretreatment of PG-61 with EHF-EMF caused at least twice increase of viability and consequent decrease of amount of red colonies. Conclusion: EHF-EMF may induce AR in yeast cells and increase their viability under UV treatment.

Keywords: Saccharomyces cerevisiae, EHF-EMF, UV light, adaptive response

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Authors: Ivna Mororó, Lise P. Labéjof, Stephanie Ribeiro, Kely Almeida

Abstract:

Lipid droplets (LDs) are normally presented in greater or lesser number in the cytoplasm of almost all eukaryotic and some prokaryotic cells. They are independent organelles composed of a lipid ester core and a surface phospholipid monolayer. As a lipid storage form, they provide an available source of energy for the cell. Recently it was demonstrated that they play an important role in other many cellular processes. Among the many unresolved questions about them, it is not even known how LDs is formed, how lipids are recruited to LDs and how they interact with the other organelles. Excess fat in the organism is pathological and often associated with the development of some genetic, hormonal or behavioral diseases. The formation and accumulation of lipid droplets in the cytoplasm can be increased by exogenous physical or chemical agents. It is well known that ionizing radiation affects lipid metabolism resulting in increased lipogenesis in cells, but the details of this process are unknown. To better understand the mode of formation of LDs in liver cells, we investigate their ultrastructural morphology after irradiation. For that, Wistar rats were exposed to whole body gamma radiation from 60-cobalt at various single doses. Samples of the livers were processed for analysis under a conventional transmission electron microscope. We found that when compared to controls, morphological changes in liver cells were evident at the higher doses of radiation used. It was detected a great number of lipid droplets of different sizes and homogeneous content and some of them merged each other. In some cells, it was observed diffused LDs, not limited by a monolayer of phospholipids. This finding suggests that the phospholipid monolayer of the LDs was disrupted by ionizing radiation exposure that promotes lipid peroxydation of endo membranes. Thus the absence of the phospholipid monolayer may prevent the realization of some cellular activities as follow: - lipid exocytosis which requires the merging of LDs membrane with the plasma membrane; - the interaction of LDs with other membrane-bound organelles such as the endoplasmic reticulum (ER), the golgi and mitochondria and; - lipolysis of lipid esters contained in the LDs which requires the presence of enzymes located in membrane-bound organelles as ER. All these impediments can contribute to lipid accumulation in the cytoplasm and the development of diseases such as liver steatosis, cirrhosis and cancer.

Keywords: radiobiology, hepatocytes, lipid metabolism, transmission electron microscopy

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