Search results for: neutron activation measurements

Authors: Maha Alhussain, Moira A Taylor, Ian A. Macdonald

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Background: It is well established that dietary composition has effects on metabolism and therefore impacts on health; however other aspects of diet, such as meal pattern, could also be important in both obesity management and promoting health. The present study investigated the effect of irregular meal frequency on anthropometric measurements and energy expenditure (EE) in healthy women. Design: 11 healthy weight women (18–40 years) were studied in a randomized crossover trial with two phases of 2 weeks each. In Phase 1, participants consumed either a regular meal pattern (6 meals/day) or an irregular meal pattern (varying from 3 to 9 meals/day). In Phase 2, participants followed the alternative meal pattern to that followed in Phase 1, after a 2-weeks washout period. In the two phases, identical foods were provided to a participant in amounts designed to keep body weight constant. Participants came to the laboratory after an overnight fast at the start and end of each phase. EE was measured in fasting state by indirect calorimetry. Postprandial EE was measured during the 3 h period after consumption of a milkshake, test drink. Results: There were no significant changes in body weight and anthropometric measurements after both meal pattern interventions. There was also no significant difference in mean daily energy intake between the regular and irregular meal pattern (2043 ±31 and 2099 ±33 respectively). EE in the fasting state showed no significant differences cross the experiment visits. There was a significant difference in Postprandial EE (measured for 3 h) by visit (P=0.04). Postprandial EE after the regular meal pattern was significantly higher than at baseline (P=0.002) or than after the irregular meal pattern (P= 0.04). Conclusion: Eating regularly for 14-day period significantly increases Postprandial EE which may contribute to weight loss and obesity management.

Keywords: energy expenditure, energy intake, meal pattern, weight loss

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Authors: Marcel Duh, Jadranka Stricevic, David Halozan, Dusan Celan

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Back pain is not only the result of structural or biomechanical abnormalities of the spine but is also associated with cognitive and behavioral aspects of pain and thus represents biopsychosocial problem. Stressors are not only interpersonal conflicts, negative life events, and dangerous situations but also noise. Effects of noise on human beings are psychological (excitement, stress), sensory, and physiological. The harmful effects of noise can be seen in the 40-65 dB range and are manifested as fatigue, irritability, poor sleep and psychological discomfort of the worker. Within 65-90 dB range, body metabolism increases, oxygen consumption is higher, tachycardia and hypertension appear, and the tone of skeletal muscles increases. The purpose of the study was to determine whether the stress caused by noise at the work place increases the incidence of back pain. Measurements of noise levels were carried out in three different wards of social care institution. The measurement on each ward was repeated 3 times (total of 9 measurements) for 8 hours during the morning shift. The device was set up in the room where clients spent most of the day. The staff on the ward replied to the questionnaire consisting of closed type questions about basic demographic information and information about back pain. We find that noise levels as measured in our study had no statistically significant effect on the incidence of back pain (p = 0.90). We also find that health care workers who perceive their work as stressful, have more back pain than those who perceive their job as unstressful, but correlation is statistically insignificant (p = 0.682). With our study, we have proven findings of other authors, that noise level below 65 dB does not have a significant influence on the incidence of back pain.

Keywords: health care workers, musculoskeletal disorder, noise, sick leave

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Authors: Recep Duzsoz, Ozlem Gormez, Umit Memis, Selma Demer, Hikmet Orhan

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Stylohyoid ligament is a connective tissue extending from apex of the styloid process to small horn of the hyoid bone. The normal length of styloid process ranges from 20 to 30 mm and measurements more than 30 mm is named stylohyoid ligament calcification (SLC). Fluorosis is a health problem that arises in individuals who intake large amounts of fluor long periods of time. The aim of this study was to investigate the effects of fluorosis on SLC. This study has been conducted on 100 patients who had SLC detected on panoramic radiograph. The study group was consisted of 50 patients with dental fluorosis and control group was consisted of 50 patients without dental fluorosis. Length and thickness of SLC were measured and the type of SLC was determined on panoramic radiographs. There was no statistically significant differences between the study and control group for SLC length, thickness and type. The thickness of left and right SLC of severe dental fluorosis group was statistically significant higher than moderate dental fluorosis group (p < 0,05). Cervicopharyngeal trauma, tonsillectomy, endocrine disease in menopause, persistent mesenchymal tissue, mechanical stress have reported as etiology of SLC in the literature and studies are still ongoing. It was reported that fluorosis as a factor on calcification of some ligaments in body (posterior longitudunal ligament, ligamentum flavum and transverse atlantal ligament) previously but relationship between fluorosis with SLC was not investigated. Our study is unique because it is the first study on SLC thickness measurements on panoramic radiographs and the relationship between fluorosis and SLC to our knowledge. According to the obtained results, it is thought that fluorosis may have an effect on SLC in thickness due to the relationship between dental fluorosis severity with SLC thickness and this study will contribute to the progress of the future studies.

Keywords: calcification, fluorosis, ligament, stylohyoid

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Authors: Omar Concepcion, Osvaldo De Melo, Arturo Escobosa

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Topological insulator (TI) materials are insulating in the bulk and conducting in the surface. The unique electronic properties associated with these surface states make them strong candidates for exploring innovative quantum phenomena and as practical applications for quantum computing, spintronic and nanodevices. Many materials, including Bi₂Te₃, have been proposed as TIs and, in some cases, it has been demonstrated experimentally by angle-resolved photoemission spectroscopy (ARPES), scanning tunneling spectroscopy (STM) and/or magnetotransport measurements. A clean surface is necessary in order to make any of this measurements. Several techniques have been used to produce films and different kinds of nanostructures. Growth and characterization in situ is usually the best option although cleaving the films can be an alternative to have a suitable surface. In the present work, we report a comparison of Bi₂Te₃ grown by physical vapor transport (PVT) and molecular beam epitaxy (MBE). The samples were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and ARPES. The Bi₂Te₃ samples grown by PVT, were cleaved in the ultra-high vacuum in order to obtain a surface free of contaminants. In both cases, the XRD shows a c-axis orientation and the pole diagrams proved the epitaxial relationship between film and substrate. The ARPES image shows the linear dispersion characteristic of the surface states of the TI materials. The samples grown by PVT, a relatively simple and cost-effective technique shows the same high quality and TI properties than the grown by MBE.

Keywords: Bismuth telluride, molecular beam epitaxy, physical vapor transport, topological insulator

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Authors: N. Demertzis, J. L. Bowen

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Sepsis is a complex and rapidly evolving condition, resulting from uncontrolled prolonged activation of host immune system due to pathogenic insult. The aim of this study is the development of a multiplex electrochemical sensing platform, capable of detecting both pathogen associated and host immune markers to enable the rapid and definitive diagnosis of sepsis. A combination of aptamers and molecular imprinting approaches have been employed to generate sensing systems for lipopolysaccharide (LPS), c-reactive protein (CRP) and procalcitonin (PCT). Gold working electrodes were mechanically polished and electrochemically cleaned with 0.1 M sulphuric acid using cyclic voltammetry (CV). Following activation, a self-assembled monolayer (SAM) was generated, by incubating the electrodes with a thiolated anti-LPS aptamer / dithiodibutiric acid (DTBA) mixture (1:20). 3-aminophenylboronic acid (3-APBA) in combination with the anti-LPS aptamer was used for the development of the hybrid molecularly imprinted sensor (apta-MIP). Aptasensors, targeting PCT and CRP were also fabricated, following the same approach as in the case of LPS, with mercaptohexanol (MCH) replacing DTBA. In the case of the CRP aptasensor, the SAM was formed following incubation of a 1:1 aptamer: MCH mixture. However, in the case of PCT, the SAM was formed with the aptamer itself, with subsequent backfilling with 1 μM MCH. The binding performance of all systems has been evaluated using electrochemical impedance spectroscopy. The apta-MIP’s polymer thickness is controlled by varying the number of electropolymerisation cycles. In the ideal number of polymerisation cycles, the polymer must cover the electrode surface and create a binding pocket around LPS and its aptamer binding site. Less polymerisation cycles will create a hybrid system which resembles an aptasensor, while more cycles will be able to cover the complex and demonstrate a bulk polymer-like behaviour. Both aptasensor and apta-MIP were challenged with LPS and compared to conventional imprinted (absence of aptamer from the binding site, polymer formed in presence of LPS) and non-imprinted polymers (NIPS, absence of LPS whilst hybrid polymer is formed). A stable LPS aptasensor, capable of detecting down to 5 pg/ml of LPS was generated. The apparent Kd of the system was estimated at 17 pM, with a Bmax of approximately 50 pM. The aptasensor demonstrated high specificity to LPS. The apta-MIP demonstrated superior recognition properties with a limit of detection of 1 fg/ml and a Bmax of 100 pg/ml. The CRP and PCT aptasensors were both able to detect down to 5 pg/ml. Whilst full binding performance is currently being evaluated, there is none of the sensors demonstrate cross-reactivity towards LPS, CRP or PCT. In conclusion, stable aptasensors capable of detecting LPS, PCT and CRP at low concentrations have been generated. The realisation of a multiplex panel such as described herein, will effectively contribute to the rapid, personalised diagnosis of sepsis.

Keywords: aptamer, electrochemical impedance spectroscopy, molecularly imprinted polymers, sepsis

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Authors: Ipek Gunay, Efe B. Orman, Metin Ozer, Bekir Salih, Ali R. Ozkaya

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Phthalocyanines with macrocyclic ring containing at least three heteroatoms have nine or more membered structures. Metal-free phthalocyanines react with metal salts to obtain chelate complexes. This is one of the most important features of metal-free phthalocyanine as ligand structure. Although phthalocyanines have very similar properties with porphyrins, they have some advantages such as lower cost, easy to prepare, and chemical and thermal stability. It’s known that Pc compounds have shown one-electron metal-and/or ligand-based reversible or quasi-reversible reduction and oxidation processes. The redox properties of phthalocyanines are critically related to the desirable properties of these compounds in their technological applications. Thus, Pc complexes have also been receiving increasing interest in the area of fuel cells due to their high electrocatalytic activity in dioxygen reduction and fuel cell applications. In this study, novel phthalocyanine complexes coordinated with Fe(II) and Co (II) to be used as catalyst were synthesized. Aiming this goal, a new nitrile ligand was synthesized starting from 4-hydroxy-3,5-dimethoxy benzyl alcohol and 4-nitrophthalonitrile in the presence of K2CO3 as catalyst. After the isolation of the new type of nitrile and metal complexes, the characterization of mentioned compounds was achieved by IR, H-NMR and UV-vis methods. In addition, the electrochemical behaviour of Pc complexes was identified by cyclic voltammetry, square wave voltammetry and in situ spectroelectrochemical measurements. Furthermore, the catalytic performances of Pc complexes for oxygen reduction were tested by dynamic voltammetry measurements, carried out by the combined system of rotating ring-disk electrode and potentiostat, in a medium similar to fuel-cell working conditions.

Keywords: phthalocyanine, electrocatalysis, electrochemistry, in-situ spectroelectrochemistry

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Authors: H. Shamoradifar, B. Teimuri, P. Parvaresh, S. Mohammadi

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One of the main characteristics of Heavy Water Moderated Reactors is their high production of plutonium. This article demonstrates the possibility of reduction of plutonium and other actinides in Heavy Water Research Reactor. Among the many ways for reducing plutonium production in a heavy water reactor, in this research, changing the fuel from natural Uranium fuel to Thorium-Uranium mixed fuel was focused. The main fissile nucleus in Thorium-Uranium fuels is U-233 which would be produced after neutron absorption by Th-232, so the Thorium-Uranium fuels have some known advantages compared to the Uranium fuels. Due to this fact, four Thorium-Uranium fuels with different compositions ratios were chosen in our simulations; a) 10% UO₂-90% THO₂ (enriched= 20%); b) 15% UO₂-85% THO₂ (enriched= 10%); c) 30% UO₂-70% THO₂ (enriched= 5%); d) 35% UO₂-65% THO₂ (enriched= 3.7%). The natural Uranium Oxide (UO₂) is considered as the reference fuel, in other words all of the calculated data are compared with the related data from Uranium fuel. Neutronic parameters were calculated and used as the comparison parameters. All calculations were performed by Monte Carol (MCNPX2.6) steady state reaction rate calculation linked to a deterministic depletion calculation (CINDER90). The obtained computational data showed that Thorium-Uranium fuels with four different fissile compositions ratios can satisfy the safety and operating requirements for Heavy Water Research Reactor. Furthermore, Thorium-Uranium fuels have a very good proliferation resistance and consume less fissile material than uranium fuels at the same reactor operation time. Using mixed Thorium-Uranium fuels reduced the long-lived α emitter, high radiotoxic wastes and the radio toxicity level of spent fuel.

Keywords: Heavy Water Reactor, Burn up, Minor Actinides, Neutronic Calculation

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Authors: Mirko Ante, Şeniz Sörgel, Andreas Bund

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Li-S- (Lithium-Sulfur-) battery systems provide very high specific gravimetric energy (2600 Wh/kg) and volumetric energy density (2800Wh/l). Hence, Li-S batteries are one of the key technologies for both the upcoming electromobility and stationary applications. Furthermore, the Li-S battery system is potentially cheap and environmentally benign. However, the technical implementation suffers from cycling stability, low charge and discharge rates and incomplete understanding of the complex polysulfide reaction mechanism. The aim of this work is to develop an effective electrocatalyst for the polysulfide reactions so that the electrode kinetics of the sulfur half-cell will be improved. Accordingly, the overvoltage will be decreased, and the efficiency of the cell will be increased. An enhanced electroactive surface additionally improves the charge and discharge rates. To reach this goal, functionalized electrocatalytic coatings are investigated to accelerate the kinetics of the polysulfide reactions. In order to determine a suitable electrocatalyst, apparent exchange current densities of a variety of materials (Ni, Co, Pt, Cr, Al, Cu, ITO, stainless steel) have been evaluated in a polysulfide containing electrolyte by potentiodynamic measurements and a Butler-Volmer fit including diffusion limitation. The samples have been examined by Scanning Electron Microscopy (SEM) after the potentiodynamic measurements. Up to now, our work shows that cobalt is a promising material with good electrocatalytic properties for the polysulfide reactions and good chemical stability in the system. Furthermore, an electrodeposition from a modified Watt’s nickel electrolyte with a sulfur source seems to provide an autocatalytic effect, but the electrocatalytic behavior decreases after several cycles of the current-potential-curve.

Keywords: electrocatalyst, energy storage, lithium sulfur battery, sulfur electrode materials

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Authors: Y. J. Song, Q. S. Xu, X. C. Wang, H. Wang, C. Q. Li

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The catalyst of copper oxide loaded on HZSM-5 was developed for nitrous oxide (N₂O) direct decomposition. The kinetic of nitrous oxide decomposition was studied for CuO/HZSM-5 catalyst prepared by incipient wetness impregnation method. The external and internal diffusion of catalytic reaction were considered in the investigation. Experiment results indicated that the external diffusion was basically eliminated when the reaction gas mixture gas hourly space velocity (GHSV) was higher than 9000h⁻¹ and the influence of the internal diffusion was negligible when the particle size of the catalyst CuO/HZSM-5 was small than 40-60 mesh. The experiment results showed that the kinetic of catalytic decomposition of N₂O was a first-order reaction and the activation energy and the pre-factor of the kinetic equation were 115.15kJ/mol and of 1.6×109, respectively.

Keywords: catalytic decomposition, CuO/HZSM-5, kinetic, nitrous oxide

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Authors: Alexa Rakoski, Yun Suk Eo, Cagliyan Kurdak, Priscila F. S. Rosa, Zachary Fisk, Monica Ciomaga Hatnean, Geetha Balakrishnan, Boyoun Kang, Myungsuk Song, Byungki Cho

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Samarium hexaboride (SmB6) is a strongly correlated mixed valence material and Kondo insulator. In the resistance-temperature curve, SmB6 exhibits activated behavior from 4-40 K after the Kondo gap forms. However, below 4 K, the resistivity is temperature independent or weakly temperature dependent due to the appearance of a topologically protected surface state. Current research suggests that the surface of SmB6 is conductive while the bulk is truly insulating, different from conventional 3D TIs (Topological Insulators) like Bi₂Se₃ which are plagued by bulk conduction due to impurities. To better understand why the bulk of SmB6 is so different from conventional TIs, this study employed a new method, called inverted resistance, to explore the lowest temperatures, as well as standard Hall measurements for the rest of the temperature range. In the inverted resistance method, current flows from an inner contact to an outer ring, and voltage is measured outside of this outer ring. This geometry confines the surface current and allows for measurement of the bulk resistivity even when the conductive surface dominates transport (below 4 K). The results confirm that the bulk of SmB6 is truly insulating down to 2 K. Hall measurements on a number of samples show consistent bulk behavior from 4-40 K, but widely varying behavior among samples above 40 K. This is attributed to a combination of the growth process and purity of the starting material, and the relationship between the high and low temperature behaviors is still being explored.

Keywords: bulk transport, Hall effect, inverted resistance, Kondo insulator, samarium hexaboride, topological insulator

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Authors: Alaa A. H. Shehada, Eman Abdelnasser Abouhassanein, Reem Mohsen Ali, Joyce J. Moawad, Hiba Bawadi, Abdelhamid Kerkadi

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Background: The association between obesity and micronutrient deficiencies is well documented. Among minerals that have been widely studied: zinc, iron and magnesium. Objectives: This study aims to determine the association between obesity indices and mineral status among Qatari adults. Methods: Secondary data was obtained from Qatar Biobank. 414 healthy Qatari aged 20-50 years old were randomly selected from the database. Anthropometric measurements (WC, Weight, and height), body fat, and mineral status (Fe, Mg, Ca, K, Na) were obtained for all selected participants. Differences in anthropometric measurements and mineral status were analyzed by t-test or ANOVA. Spearman correlation coefficients were determined to assess the association between minerals and anthropometric variables. Statistical significance for the hypothesis tests was set at p <0.05. All statistical analysis was preformed using SPSS software version 23.0. Results: Iron, calcium, and sodium levels decreased with an increase in body mass index. Moreover, only iron showed a significant correlation with waist circumference, and waist to height ratio increased. Additionally, calcium, iron, magnesium, and sodium had a statistically significant negative correlation with total body fat percentage and trunk fat percentage. There were statistically significant negative correlations of anthropometrics with minerals. Conclusion: Body fat and trunk fat percentage had a significant inverse relationship with iron, calcium, sodium, and magnesium, while there was no correlation between body fat or trunk fat percentage with potassium.

Keywords: Qatar biobank, body fat distribution, mineral status, Qatari adults

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Authors: Yahia Massinissa, Melakhessou Med Akram, Mezahdia Mehdi, Marref Salah Eddine

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Cytokines are natural proteins which act as true intercellular communication signals in immune and inflammatory responses. Reverse signaling pathways that activate cytokines help to regulate different functions at the target cell, causing its activation, its proliferation, the differentiation, its survival or death. It was shown that malfunctioning of the cytokine regulation, particularly over-expression, contributes to the onset and development of certain serious diseases such as chronic rheumatoid arthritis, Crohn's disease, psoriasis, lupus. The action mode of Kinoid® technology is based on the principle vaccine: The patient's immune system is activated so that it neutralizes itself and the factor responsible for the disease. When applied specifically to autoimmune diseases, therapeutic vaccination allows the body to neutralize cytokines (proteins) overproduced through a highly targeted stimulation of the immune system.

Keywords: cytokines, Kinoid tech, auto-immune diseases, vaccination

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Authors: Prashant Sharma, Jyotsna Dutta Majumdar

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The present study concerns development of a composite thermal barrier coating consisting of a mixture of La2O3 and YSZ (with 8 wt.%, 32 wt.% and 50 wt.% 50% La2O3) by plasma spray deposition technique on a CoNiCrAlY based bond coat deposited on Inconel 718 substrate by high velocity oxy-fuel deposition (HVOF) technique. The addition of La2O3 in YSZ causes the formation of pyrochlore (La2Zr2O7) phase in the inter splats boundary along with the presence of LaYO3 phase. The coefficient of thermal expansion is significantly reduced from due to the evolution of different phases and structural defects in the sprayed coating. The activation energy for TGO growth under isothermal and cyclic oxidation was increased in the composite coating as compared to YSZ coating.

Keywords: plasma spraying, oxidation resistance, thermal barrier coating, microstructure, X-ray method

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Authors: Serdar Delice, Mehmet Isik, Nizami Hasanli, Kadir Goksen

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Researchers have donated great interest to ternary and quaternary semiconductor compounds especially with the improvement of the optoelectronic technology. The quaternary compound Tl2Ga2Se3S which was grown by Bridgman method carries the properties of ternary thallium chalcogenides group of semiconductors with layered structure. This compound can be formed from TlGaSe2 crystals replacing the one quarter of selenium atom by sulfur atom. Although Tl2Ga2Se3S crystals are not intentionally doped, some unintended defect types such as point defects, dislocations and stacking faults can occur during growth processes of crystals. These defects can cause undesirable problems in semiconductor materials especially produced for optoelectronic technology. Defects of various types in the semiconductor devices like LEDs and field effect transistor may act as a non-radiative or scattering center in electron transport. Also, quick recombination of holes with electrons without any energy transfer between charge carriers can occur due to the existence of defects. Therefore, the characterization of defects may help the researchers working in this field to produce high quality devices. Thermoluminescence (TL) is an effective experimental method to determine the kinetic parameters of trap centers due to defects in crystals. In this method, the sample is illuminated at low temperature by a light whose energy is bigger than the band gap of studied sample. Thus, charge carriers in the valence band are excited to delocalized band. Then, the charge carriers excited into conduction band are trapped. The trapped charge carriers are released by heating the sample gradually and these carriers then recombine with the opposite carriers at the recombination center. By this way, some luminescence is emitted from the samples. The emitted luminescence is converted to pulses by using an experimental setup controlled by computer program and TL spectrum is obtained. Defect characterization of Tl2Ga2Se3S single crystals has been performed by TL measurements at low temperatures between 10 and 300 K with various heating rate ranging from 0.6 to 1.0 K/s. The TL signal due to the luminescence from trap centers revealed one glow peak having maximum temperature of 36 K. Curve fitting and various heating rate methods were used for the analysis of the glow curve. The activation energy of 13 meV was found by the application of curve fitting method. This practical method established also that the trap center exhibits the characteristics of mixed (general) kinetic order. In addition, various heating rate analysis gave a compatible result (13 meV) with curve fitting as the temperature lag effect was taken into consideration. Since the studied crystals were not intentionally doped, these centers are thought to originate from stacking faults, which are quite possible in Tl2Ga2Se3S due to the weakness of the van der Waals forces between the layers. Distribution of traps was also investigated using an experimental method. A quasi-continuous distribution was attributed to the determined trap centers.

Keywords: chalcogenides, defects, thermoluminescence, trap centers

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Authors: Mahacine Amrani

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A simple and rapid method for the determination of alcohol in gasoline-alcohol mixtures using density measurements is described. The method can determine a minimum of 1% of alcohol by volume. The precision of the method is ± 3%.The method is more useful for field test in the quality assessment of alcohol blended fuels.

Keywords: gasoline-alcohol, mixture, alcohol determination, density, measurement, Morocco

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Authors: Shahbaa F. Bdewi, Bakhtyar K. Aziz, Ayad A. R. Mutar

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Nano-materials show different surface properties due to their high surface area and active sites. This study investigates the feasibility of using nano-MgO (NMO) for removing Congo red (CR) dye from wastewater. NMO was prepared by molten salt method. Equilibrium experiments show the equilibrium was reached after 120 minutes and maximum adsorption efficiency was obtained in acidic media up to pH 6. Isotherm studies revealed the favorability of the adsorption process. The overall adsorption process was spontaneous and endothermic in nature with a maximum adsorption capacity of 1100 mg g-1 at 40°C as estimated from Langmuir isotherm. The adsorption kinetics was found to follow pseudo second-order rate equation. Relatively high activation energy (180.7 kJ mol-1) was obtained which is consistent with chemisorption mechanism for the adsorption process.

Keywords: adsorption, congo red, magnesium oxide, nanoparticles

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Authors: Sourav Ray, Christoph Stein, Marcus Weber

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A new class of drug candidates, initially derived from mathematical modeling of ligand-receptor interactions, activate the μ-opioid receptor (MOR) preferentially at acidic extracellular pH-levels, as present in injured tissues. This is of commercial interest because it may preclude the adverse effects of conventional MOR agonists like fentanyl, which include but are not limited to addiction, constipation, sedation, and apnea. Animal studies indicate the importance of taking the pH value of the chemical environment of MOR into account when designing new drugs. Hydrogen bonds (HBs) play a crucial role in stabilizing protein secondary structure and molecular interaction, such as ligand-protein interaction. These bonds may depend on the pH value of the chemical environment. For the MOR, antagonist naloxone and agonist [D-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin (DAMGO) form HBs with ionizable residue HIS 297 at physiological pH to modulate signaling. However, such interactions were markedly reduced at acidic pH. Although fentanyl-induced signaling is also diminished at acidic pH, HBs with HIS 297 residue are not observed at either acidic or physiological pH for this strong agonist of the MOR. Molecular dynamics (MD) simulations can provide greater insight into the interaction between the ligand of interest and the HIS 297 residue. Amino acid protonation states are adjusted to the model difference in system acidity. Unbiased and unrestrained MD simulations were performed, with the ligand in the proximity of the HIS 297 residue. Ligand-receptor complexes were embedded in 1-palmitoyl-2-oleoyl-sn glycero-3-phosphatidylcholine (POPC) bilayer to mimic the membrane environment. The occurrence of HBs between the different ligands and the HIS 297 residue of MOR at acidic and physiological pH values were tracked across the various simulation trajectories. No HB formation was observed between fentanyl and HIS 297 residue at either acidic or physiological pH. Naloxone formed some HBs with HIS 297 at pH 5, but no such HBs were noted at pH 7. Interestingly, DAMGO displayed an opposite yet more pronounced HB formation trend compared to naloxone. Whereas a marginal number of HBs could be observed at even pH 5, HBs with HIS 297 were more stable and widely present at pH 7. The HB formation plays no and marginal role in the interaction of fentanyl and naloxone, respectively, with the HIS 297 residue of MOR. However, HBs play a significant role in the DAMGO and HIS 297 interaction. Post DAMGO administration, these HBs might be crucial for the remediation of opioid tolerance and restoration of opioid sensitivity. Although experimental studies concur with our observations regarding the influence of HB formation on the fentanyl and DAMGO interaction with HIS 297, the same could not be conclusively stated for naloxone. Therefore, some other supplementary interactions might be responsible for the modulation of the MOR activity by naloxone binding at pH 7 but not at pH 5. Further elucidation of the mechanism of naloxone action on the MOR could assist in the formulation of cost-effective naloxone-based treatment of opioid overdose or opioid-induced side effects.

Keywords: effect of system acidity, hydrogen bond formation, opioid action, receptor activation

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Authors: M. Chobotová, Ž. Rylková

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Time full of changes which is associated with globalization, tougher competition, changes in the structures of markets and economic downturn, that all force companies to think about their competitive advantages. These changes can bring the company a competitive advantage and that can help improve competitive position in the market. Policy of the European Union is focused on the fast growing innovative companies which quickly respond to market demands and consequently increase its competitiveness. To meet those objectives companies need the right conditions and support of their state.

Keywords: innovation, performance, measurements metrics, indices

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Authors: Magarò Floriana, Zinno Raffaele

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Since 2009, with the coming into force of the January 14, 2008 Ministerial Decree "New technical standards for construction", and the explanatory ministerial circular N°.617 of February 2, 2009, the question of seismic hazard and the design of seismic-resistant structures in Italy has acquired increasing importance. One of the most discussed aspects in recent Italian and international scientific literature concerns the dynamic interaction between land and structure, and the effects which dynamic coupling may have on individual buildings. In effect, from systems dynamics, it is well known that resonance can have catastrophic effects on a stimulated system, leading to a response that is not compatible with the previsions in the design phase. The method used in this study to estimate the frequency of oscillation of the structure is as follows: the analysis of HVSR (Horizontal to Vertical Spectral Ratio) relations. This allows for evaluation of very simple oscillation frequencies for land and structures. The tool used for data acquisition is an experimental digital tromograph. This is an engineered development of the experimental Languamply RE 4500 tromograph, equipped with an engineered amplification circuit and improved electronically using extremely small electronic components (size of each individual amplifier 16 x 26 mm). This tromograph is a modular system, completely "free" and "open", designed to interface Windows, Linux, OSX and Android with the outside world. It an amplifier designed to carry out microtremor measurements, yet which will also be useful for seismological and seismic measurements in general. The development of single amplifiers of small dimension allows for a very clean signal since being able to position it a few centimetres from the geophone eliminates cable “antenna” phenomena, which is a necessary characteristic in seeking to have signals which are clean at the very low voltages to be measured.

Keywords: microtremor, HVSR, tromograph, structural engineering

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Authors: M. Çevik, S. Sabancı, D. Tezcan, C. Çelebi, F. İçier

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Ultrasound technology is the one of the non-thermal food processing method in recent years which has been used widely in the food industry. Ultrasound application in the food industry is divided into two groups: low and high intensity ultrasound application. While low intensity ultrasound is used to obtain information about physicochemical properties of foods, high intensity ultrasound is used to extract bioactive components and to inactivate microorganisms and enzymes. In this study, the ultrasound pre-treatment at a constant power (1500 W) and fixed frequency (20 kHz) was applied to the red beetroot slices having the dimension of 25×25×50 mm at the constant temperature (25°C) for different application times (0, 5, 10, 15 and 20 min). The red beet root slices pretreated with ultrasonication was squeezed immediately. The changes on rheological properties of red beet root juice depending on ultrasonication duration applied to slices were investigated. Rheological measurements were conducted by using Brookfield viscometer (LVDV-II Pro, USA). Shear stress-shear rate data was obtained from experimental measurements for 0-200 rpm range by using spindle 18. Rheological properties of juice were determined by fitting this data to some rheological models (Newtonian, Bingham, Power Law, Herschel Bulkley). It was investigated that the best model was Power Law model for both untreated red beet root juice (R2=0.991, χ2=0.0007, RMSE=0.0247) and red beetroot juice produced from ultrasonicated slices (R2=0.993, χ2=0.0006, RMSE=0.0216 for 20 min pre-treatment). k (consistency coefficient) and n (flow behavior index) values of red beetroot juices were not affected from the duration of ultrasonication applied to the slices. Ultrasound treatment does not result in any changes on the rheological properties of red beetroot juice. This can be explained by lack of ability to homogenize of the intensity of applied ultrasound.

Keywords: ultrasonication, rheology, red beet root slice, juice

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Authors: D. S. Gomes, A. T. Silva

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Analysis of the uncertainty quantification related to nuclear safety margins applied to the nuclear reactor is an important concept to prevent future radioactive accidents. The nuclear fuel performance code may involve the tolerance level determined by traditional deterministic models producing acceptable results at burn cycles under 62 GWd/MTU. The behavior of nuclear fuel can simulate applying a series of material properties under irradiation and physics models to calculate the safety limits. In this study, theoretical predictions of nuclear fuel failure under transient conditions investigate extended radiation cycles at 75 GWd/MTU, considering the behavior of fuel rods in light-water reactors under reactivity accident conditions. The fuel pellet can melt due to the quick increase of reactivity during a transient. Large power excursions in the reactor are the subject of interest bringing to a treatment that is known as the Fuchs-Hansen model. The point kinetic neutron equations show similar characteristics of non-linear differential equations. In this investigation, the multivariate logistic regression is employed to a probabilistic forecast of fuel failure. A comparison of computational simulation and experimental results was acceptable. The experiments carried out use the pre-irradiated fuels rods subjected to a rapid energy pulse which exhibits the same behavior during a nuclear accident. The propagation of uncertainty utilizes the Wilk's formulation. The variables chosen as essential to failure prediction were the fuel burnup, the applied peak power, the pulse width, the oxidation layer thickness, and the cladding type.

Keywords: logistic regression, reactivity-initiated accident, safety margins, uncertainty propagation

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Authors: Palwinder Singh

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Beyond the conventional mode of working with anti-inflammatory agents through enzyme inhibition, herein, an alternate substrate of cyclooxygenase-2 was developed. Proline centered pentapeptide iso-conformational to arachidonic acid exhibited appreciable selectivity for COX-2 overcoming acetic acid and formalin induced pain in rats to almost 80% and was treated as a substrate by the enzyme. Remarkably, COX-2 metabolized the pentapeptide into small fragments consisting mainly of di- and tri-peptides that ensured the safe breakdown of the peptide under in-vivo conditions. The kinetic parameter Kcat/Km for COX-2 mediated metabolism of peptide 6.3 x 105 M-1 s-1 was quite similar to 9.5 x 105 M-1 s-1 for arachidonic acid. Evidenced by the dynamic molecular studies and the use of Y385F COX-2, it was observed that the breakage of the pentapeptide has probably taken place through H-bond activation of the peptide bond by the side chains of Y385 and S530.

Keywords: small peptides, anti-inflammatory agents, cyclooxygenase-2, unnatural substrates

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Authors: Samy A. Khalil, U. Ali Rahoma

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The measurements of solar radiation, satellite data has been routinely utilize to estimate solar energy. However, the temporal coverage of satellite data has some limits. The reanalysis, also known as "retrospective analysis" of the atmosphere's parameters, is produce by fusing the output of NWP (Numerical Weather Prediction) models with observation data from a variety of sources, including ground, and satellite, ship, and aircraft observation. The result is a comprehensive record of the parameters affecting weather and climate. The effectiveness of reanalysis datasets (ERA-5) for North Africa was evaluate against high-quality surfaces measured using statistical analysis. Estimating the distribution of global solar radiation (GSR) over five chosen areas in North Africa through ten-years during the period time from 2011 to 2020. To investigate seasonal change in dataset performance, a seasonal statistical analysis was conduct, which showed a considerable difference in mistakes throughout the year. By altering the temporal resolution of the data used for comparison, the performance of the dataset is alter. Better performance is indicate by the data's monthly mean values, but data accuracy is degraded. Solar resource assessment and power estimation are discuses using the ERA-5 solar radiation data. The average values of mean bias error (MBE), root mean square error (RMSE) and mean absolute error (MAE) of the reanalysis data of solar radiation vary from 0.079 to 0.222, 0.055 to 0.178, and 0.0145 to 0.198 respectively during the period time in the present research. The correlation coefficient (R2) varies from 0.93 to 99% during the period time in the present research. This research's objective is to provide a reliable representation of the world's solar radiation to aid in the use of solar energy in all sectors.

Keywords: solar energy, ERA-5 analysis data, global solar radiation, North Africa

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Authors: Xiaoling Ren, Guidong Yang

Abstract:

As one of the largest industrial synthetic chemicals in the world, ammonia has the advantages of high energy density, easy liquefaction, and easy transportation, which is widely used in agriculture, chemical industry, energy storage, and other fields. The industrial Haber-Bosch method process for ammonia synthesis is generally conducted under severe conditions. It is essential to develop a green, sustainable strategy for ammonia production to meet the growing demand. In this direction, photocatalytic nitrogen reduction has huge advantages over the traditional, well-established Haber-Bosch process, such as the utilization of natural sun light as the energy source and significantly lower pressure and temperature to affect the reaction process. However, the high activation energy of nitrogen and the low efficiency of photo-generated electron-hole separation in the photocatalyst result in low ammonia production yield. Many researchers focus on improving the catalyst. In addition to modifying the catalyst, improving the dispersion of the catalyst and making full use of active sites are also means to improve the overall catalytic activity. Few studies have been carried out on this, which is the aim of this work. In this work, by making full use of the nitrogen activation ability of WO3-x with defective sites, small size WO3-x photocatalyst with high dispersibility was constructed, while the growth of WO3-x was restricted by using a high specific surface area mesoporous SBA-15 molecular sieve with the regular pore structure as a template. The morphology of pure SBA-15 and WO3-x/SBA-15 was characterized byscanning electron microscopy (SEM). Compared with pure SBA-15, some small particles can be found in the WO3-x/SBA-15 material, which means that WO3-x grows into small particles under the limitation of SBA-15, which is conducive to the exposure of catalytically active sites. To elucidate the chemical nature of the material, the X-ray diffraction (XRD) analysis was conducted. The observed diffraction pattern inWO3-xis in good agreement with that of the JCPDS file no.71-2450. Compared with WO3-x, no new peaks appeared in WO3-x/SBA-15.It can be concluded that WO3-x/SBA-15 was synthesized successfully. In order to provide more active sites, the mass content of WO3-x was optimized. Then the photocatalytic nitrogen reduction performances of above samples were performed with methanol as a hole scavenger. The results show that the overall ammonia production performance of WO3-x/SBA-15 is improved than pure bulk WO3-x. The above results prove that making full use of active sites is also a means to improve overall catalytic activity.This work provides material basis for the design of high-efficiency photocatalytic nitrogen reduction catalysts.

Keywords: ammonia, photocatalytic, nitrogen reduction, WO3-x, high dispersibility

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Authors: Anaelle Gabet, Helene Metivier, Christine De Brauer, Gilles Mailhot, Marcello Brigante

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The presence of micropollutants in surface waters has been widely reported around the world, particularly downstream from wastewater treatment plants (WWTPs). Rural WWTPs constitute more than 90 % of the total WWTPs in France. Like conventional ones, they are not able to fully remove micropollutants. Estrogens are excreted by human beings every day and several studies have highlighted their endocrine disruption properties on river wildlife. They are mainly estrone (E1), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2). Rural WWTPs require cheap and robust tertiary processes. UVC activation of H₂O₂ for HO· generation, a very reactive molecule, has demonstrated its effectiveness. However, UVC rays are dangerous to manipulate and energy-consuming. This is why the ability of UVA rays was investigated in this study. Moreover, the use of S₂O₈²⁻ for SO₄·- generation as an alternative to HO· has emerged in the last few years. Such processes have been widely studied on a lab scale. However, pilot-scale works constitute fewer studies. This study was carried out on a 20-L pilot composed of a 1.12-L UV reactor equipped with a polychromatic UVA lamp or a monochromatic (254 nm) UVC lamp fed in recirculation. Degradation rates of a mixture of spiked E1, E2 and EE2 (5 µM each) were followed by HPLC-UV. Results are expressed in UV dose (mJ.cm-2) received by the compounds of interest to compare UVC and UVA. In every system, estrogen degradation rates followed pseudo-first-order rates. First, experiments were carried out in tap water. All estrogens underwent photolysis under UVC rays, although E1 photolysis is higher. However, only very weak photolysis was observed under UVA rays. Preliminary studies on both oxidants have shown that S₂O₈²⁻ photolysis constants are higher than H₂O₂ under both UVA and UVC rays. Therefore, estrogen degradation rates are about ten times higher in the presence of 1 mM of S₂O₈²⁻ than with one mM of H₂O₂ under both radiations. In the same conditions, the mixture of interest required about 40 times higher UV dose when using UVA rays compared to UVC. However, the UVA/S₂O₈²⁻ system only requires four times more UV dose than the conventional UVC/H₂O₂ system. Further studies were carried out in WWTP effluent with the UVC lamp. When comparing these results to the tap water ones, estrogen degradation rates were more inhibited in the S₂O₈²⁻ system than with H₂O₂. It seems that SO₄·- undergo higher quenching by a real effluent than HO·. Preliminary experiments have shown that natural organic matter is mainly responsible for the radical quenching and that HO and SO₄ both had similar second-order reaction rate constants with dissolved organic matter. However, E1, E2 and EE2 second-order reaction rate constants are about ten times lower with SO₄ than with HO. In conclusion, the UVA/S₂O₈²⁻ system showed encouraging results for the use of UVA rays but further studies in WWTP effluent have to be carried out to confirm this interest. The efficiency of other pollutants in the real matrix also needs to be investigated.

Keywords: AOPs, decontamination, estrogens, radicals, wastewater

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Authors: P. S. Thein, S. Pramumijoyo, K. S. Brotopuspito, J. Kiyono, W. Wilopo, A. Furukawa, A. Setianto

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In this study, we estimated the seismic ground motion parameters based on microtremor measurements at Palu City. Several earthquakes have struck along the Palu-Koro Fault during recent years. The USGS epicenter, magnitude Mw 6.3 event that occurred on January 23, 2005 caused several casualties. We conducted a microtremor survey to estimate the strong ground motion distribution during the earthquake. From this survey we produced a map of the peak ground acceleration, velocity, seismic vulnerability index and ground shear strain maps in Palu City. We performed single observations of microtremor at 151 sites in Palu City. We also conducted 8-site microtremors array investigation to gain a representative determination of the soil condition of subsurface structures in Palu City. From the array observations, Palu City corresponds to relatively soil condition with Vs ≤ 300 m/s, the predominant periods due to horizontal vertical ratios (HVSRs) are in the range of 0.4 to 1.8 s and the frequency are in the range of 0.7 to 3.3 Hz. Strong ground motions of the Palu area were predicted based on the empirical stochastic green’s function method. Peak ground acceleration and velocity becomes more than 400 gal and 30 kine in some areas, which causes severe damage for buildings in high probability. Microtremor survey results showed that in hilly areas had low seismic vulnerability index and ground shear strain, whereas in coastal alluvium was composed of material having a high seismic vulnerability and ground shear strain indication.

Keywords: Palu-Koro fault, microtremor, peak ground acceleration, peak ground velocity, seismic vulnerability index

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Authors: Prangya P. Sahoo, B. S. Murty

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The present study deals with phase evolution of oxide dispersed CoCrFeMnNi high entropy alloy as a function of amount of added Y2O3 during mechanical alloying and analysis of grain growth kinetics of CoCrFeMnNi high entropy alloy without and with oxide dispersion. Mechanical alloying of CoCrFeMnNi resulted in a single FCC phase. However, evolution of chromium carbide was observed after heat treatment between 1073 and 1473 K. Comparison of grain growth time exponents and activation energy barrier is also reported. Micro structural investigations, using electron microscopy and EBSD techniques, were carried out to confirm the enhanced grain growth resistance which is attributed to the presence oxide dispersoids.

Keywords: grain growth kinetics, mechanical alloying, oxide dispersion, phase evolution

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Authors: Kyoungjin Kim

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Nanoscale thermites such as the composite mixture of nano-sized aluminum and molybdenum trioxide powders possess several technical advantages such as much higher reaction rate and shorter ignition delay, when compared to the conventional energetic formulations made of micron-sized metal and oxidizer particles. In this study, the self-propagation of combustion wave in compacted pellets of nanoscale thermite composites is modeled and computationally investigated by utilizing the activation energy reduction of aluminum particles due to nanoscale particle sizes. The present computational model predicts the speed of combustion wave propagation which is good agreement with the corresponding experiments of thermite reaction. Also, several characteristics of thermite reaction in nanoscale composites are discussed including the ignition delay and combustion wave structures.

Keywords: nanoparticles, thermite reaction, combustion wave, numerical modeling

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Authors: Didier Auroux, Vladimir Groza

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This work is part of STEEP Marie-Curie ITN project, and it focuses on the identification of unknown parameters of the proposed generic Abrasive WaterJet Milling (AWJM) PDE model, that appears as an ill-posed inverse problem. The necessity of studying this problem comes from the industrial milling applications where the possibility to predict and model the final surface with high accuracy is one of the primary tasks in the absence of any knowledge of the model parameters that should be used. In this framework, we propose the identification of model parameters by minimizing a cost function, measuring the difference between experimental and numerical solutions. The adjoint approach based on corresponding Lagrangian gives the opportunity to find out the unknowns of the AWJM model and their optimal values that could be used to reproduce the required trench profile. Due to the complexity of the nonlinear problem and a large number of model parameters, we use an automatic differentiation software tool (TAPENADE) for the adjoint computations. By adding noise to the artificial data, we show that in fact the parameter identification problem is highly unstable and strictly depends on input measurements. Regularization terms could be effectively used to deal with the presence of data noise and to improve the identification correctness. Based on this approach we present results in 2D and 3D of the identification of the model parameters and of the surface prediction both with self-generated data and measurements obtained from the real production. Considering different types of model and measurement errors allows us to obtain acceptable results for manufacturing and to expect the proper identification of unknowns. This approach also gives us the ability to distribute the research on more complex cases and consider different types of model and measurement errors as well as 3D time-dependent model with variations of the jet feed speed.

Keywords: Abrasive Waterjet Milling, inverse problem, model parameters identification, regularization

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Authors: Houneïda Benbouzid, Houria Berrebbah, Mohammed-Réda Djebar

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The toxicological impacts of the increasing number of synthetic compounds present in the aquatic environment are assessed predominantly in laboratory studies where test organisms are exposed to a range of concentrations of single compounds. The bio-indicator Paramecium sp., characterized by a short life cycle, rapid multiplication and normal behavior that may be affected by the presence of pollutants. We therefore investigated the inhibitory effect of a newly synthesized acaricide: the chlorfenapyr tested at concentrations of 250, 300, and 350 µM on a pure culture of Paramecium sp. during 6 day. Paramecia treated with different concentrations of Chlorfenapyr illustrate strong inhibition of cell growth from the second day of treatment. Low levels of glutathione, increased glutathione S-transferase and the decrease in respiratory metabolism, recorded in the presence of different concentrations of Chlorfenapyr, involve the activation of detoxification system.

Keywords: Paramecium sp., chlorfenapyr, oxidative enzymes, detoxification

Procedia PDF Downloads 367