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Commenced in January 2007
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Paper Count: 21208

Search results for: high dosage drugs

13498 Organic Geochemistry and Oil-Source Correlation of Cretaceous Sediments in the Kohat Basin, Pakistan

Authors: Syed Mamoon Siyar, Fayaz Ali, Sajjad Ahmad, Samina Jahandad, George Kontakiotis, Hammad T. Janjuhah, Assimina Antonarakou, Waqas Naseem

Abstract:

The Cretaceous Chichali Formation in the Chanda-01, Chanda-02, Chanda-03 and Mela-05 wells and the oil samples from Chanda-01 and Chanda-01 wells located in the Kohat Basin, Pakistan, were analyzed with the objectives of evaluating the hydrocarbon generation potential, source, thermal maturity and depositional of organic matter, and oil-source correlation by employing geochemical screening techniques and biomarker studies. The total organic carbon (TOC) values in Chanda-02, Chanda-03 and Mela-05 indicate, in general, poor to fair, fair and fair to good source rock potential with low genetic potential, respectively. The nature of organic matter has been determined by standard cross plots of Rock Eval pyrolysis parameters, indicating that studied cuttings from the Chichali Formation dominantly contain type III kerogen at present and show maturity for oil generation in the studied wells. The organic petrographic study also confirmed the vitrinite (type III) as a major maceral in the investigated Chichali Shales and its reflectance values show maturity for oil. The different ratios of non-biomarkers and biomarkers i.e., steranes, terpenes and aromatics parameters, indicate the marine source of organic matter deposited in the anoxic environment for the Chichali Formation in Chanda-01 and Chanda-02 wells and mixed source input of organic matter deposited in suboxic conditions for oil in the same wells. The CPI, and different biomarkers parameters such as C29 S/S+R, ββ/αα+ββ), M29/H30, Ts/Ts+Tm, H31 (S/S+R) and aromatic compounds methyl phenanthrene index (MPI) and organic petrographic analysis (vitrinite reflectance) suggest mature stage of oil generation for Chichali Shales and oil samples in the study area with little high thermal maturity in case of oils. Based on source and thermal maturity biomarkers and non-biomarkers parameters, the produced oils have no correlation with the Cretaceous Chichali Formation in the studied Chanda-01 and Chanda-02 wells in Kohat Basin, Pakistan, but it has been suggested that these oils have been generated by the strata containing high terrestrial organic input compare to Chichali Shales.

Keywords: Organic geochemistry, Chichali Shales and crude oils, Kohat Basin, Pakistan

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13497 Hyperspectral Imagery for Tree Speciation and Carbon Mass Estimates

Authors: Jennifer Buz, Alvin Spivey

Abstract:

The most common greenhouse gas emitted through human activities, carbon dioxide (CO2), is naturally consumed by plants during photosynthesis. This process is actively being monetized by companies wishing to offset their carbon dioxide emissions. For example, companies are now able to purchase protections for vegetated land due-to-be clear cut or purchase barren land for reforestation. Therefore, by actively preventing the destruction/decay of plant matter or by introducing more plant matter (reforestation), a company can theoretically offset some of their emissions. One of the biggest issues in the carbon credit market is validating and verifying carbon offsets. There is a need for a system that can accurately and frequently ensure that the areas sold for carbon credits have the vegetation mass (and therefore for carbon offset capability) they claim. Traditional techniques for measuring vegetation mass and determining health are costly and require many person-hours. Orbital Sidekick offers an alternative approach that accurately quantifies carbon mass and assesses vegetation health through satellite hyperspectral imagery, a technique which enables us to remotely identify material composition (including plant species) and condition (e.g., health and growth stage). How much carbon a plant is capable of storing ultimately is tied to many factors, including material density (primarily species-dependent), plant size, and health (trees that are actively decaying are not effectively storing carbon). All of these factors are capable of being observed through satellite hyperspectral imagery. This abstract focuses on speciation. To build a species classification model, we matched pixels in our remote sensing imagery to plants on the ground for which we know the species. To accomplish this, we collaborated with the researchers at the Teakettle Experimental Forest. Our remote sensing data comes from our airborne “Kato” sensor, which flew over the study area and acquired hyperspectral imagery (400-2500 nm, 472 bands) at ~0.5 m/pixel resolution. Coverage of the entire teakettle experimental forest required capturing dozens of individual hyperspectral images. In order to combine these images into a mosaic, we accounted for potential variations of atmospheric conditions throughout the data collection. To do this, we ran an open source atmospheric correction routine called ISOFIT1 (Imaging Spectrometer Optiman FITting), which converted all of our remote sensing data from radiance to reflectance. A database of reflectance spectra for each of the tree species within the study area was acquired using the Teakettle stem map and the geo-referenced hyperspectral images. We found that a wide variety of machine learning classifiers were able to identify the species within our images with high (>95%) accuracy. For the most robust quantification of carbon mass and the best assessment of the health of a vegetated area, speciation is critical. Through the use of high resolution hyperspectral data, ground-truth databases, and complex analytical techniques, we are able to determine the species present within a pixel to a high degree of accuracy. These species identifications will feed directly into our carbon mass model.

Keywords: hyperspectral, satellite, carbon, imagery, python, machine learning, speciation

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13496 Effect of Mindfulness Training on Psychological Well-Being: An Experimental Study Using a Mobile App as Intervention

Authors: Beeto W. C. Leung, Nicole C. Y. Lee

Abstract:

It was well known that college students experienced a high level of stress and anxiety. College athletes, a special group of college students, may even encounter a higher level of pressure and distress due to their dual endeavors in academic and athletic settings. Due to the high demands and costs of mental health services, easily accessible, web-based self-help interventions are getting more popular. The aim of the present experimental study was to examine the potential intervention effect of a mindfulness-based self-help mobile App, called 'Smiling Mind', on mindfulness and psychological well-being. Forty-six college athletes, recruited from athletic teams of two local universities in Hong Kong, were randomly assigned to the Mindfulness App Group (MAG) and the Control Group (CG). All participants were administered the Mindful Attention Awareness Scale, Geriatric Depression Scale, and Perceived Stress Scale-10 before the study (Time 1, T1) and after the 4-week intervention (Time 2, T2). MAG was requested to use the app and follow the instructions every day for at least 5 days per week. Participants were also asked to record their daily app usage time. Results showed that, for MAG, from T1 to T2, mindfulness has been increased from 3.25 to 3.92; depressive symptoms and stress has been significantly decreased from 8.6 to 5.1 and 24.8 to 13.5 respectively while for the CG, mindfulness has been decreased slightly from 3.29 to 3.13; depressive symptoms and stress has been slightly increased from 7.1 to 7.3 and 24.1 to 27.1 respectively. Three mixed-design ANOVAs with time (T1, T2) as the within-subjects factor and intervention group (MAG, CG) as the between-subjects factor revealed a main effect of time on mindfulness, F(1, 41) = 10.28, p < 0.01, depressive symptoms, F(1, 41) = 6.55, p < 0.02 and stress, F(1, 41) = 16.96, p < 0.001 respectively. Both predicted interaction between time and intervention group on mindfulness, F(1, 41) = 26.6, p < 0.001, ηp 2 =0.39, depressive symptoms, F(1, 41) = 8.00, p < 0.01, ηp 2 =0.16 and Stress F(1, 41) = 49.3, p < 0.001, ηp 2 =0.55 were significant meaning that participants using the Mindfulness Mobile App in the intervention did experienced a significant increase in mindfulness and significant decrease in depressive symptoms and perceived level of stress after the 4-week intervention when compared with the control group. The present study provided encouraging empirical support for using Smiling Mind, a self-help mobile app, to promote mindfulness and mental health in a cost-effective way. Further studies should examine the potential use of Smiling Mind in different samples, including children and adolescence, as well as, investigate the lasting effects of using the app on other psychosocial outcomes such as emotional regulations.

Keywords: college athletes, experimental study, mindfulness mobile apps, psychological well-being

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13495 High-Temperature Corrosion of Aluminized and Chromized Fe-25.8%Cr-19.5%Ni Alloys in N2/H2S/H2O-mixed Gases

Authors: Min Jung Kim, Dong Bok Lee

Abstract:

Alloys of Fe-25.8%Cr-19.5%Ni (SUS310 stainless steel) were either chromized or aluminized via pack cementation, and corroded at 800 oC for 100 h in 1 atm of (0.9448 atm of N2+0.031 atm of H2O+0.0242 atm of H2S)-mixed gases. The chromized layer consisted primarily of Cr1.36Fe0.52 and some Cr23C6. Its corrosion resulted in the formation of Cr2S3 and some FeS and Fe5Ni4S8. The aluminized coating consisted primarily of FeAl. Its corrosion resulted in the formation of α-Al2O3, Al2S3, and Cr2S3. Aluminizing was more effective than chromizing in increasing the corrosion resistance of the substrate, due mainly to the formation of α-Al2O3.

Keywords: aluminizing, chromizing, corrosion, H2S gas

Procedia PDF Downloads 490
13494 Efficient Variable Modulation Scheme Based on Codebook in the MIMO-OFDM System

Authors: Yong-Jun Kim, Jae-Hyun Ro, Chang-Bin Ha, Hyoung-Kyu Song

Abstract:

Because current wireless communication requires high reliability in a limited bandwidth environment, this paper proposes the variable modulation scheme based on the codebook. The variable modulation scheme adjusts transmission power using the codebook in accordance with hannel state. Also, if the codebook is composed of many bits, the reliability is more improved by the proposed scheme. The simulation results show that the performance of proposed scheme has better reliability than the the performance of conventional scheme.

Keywords: MIMO-OFDM, variable modulation, codebook, channel state

Procedia PDF Downloads 587
13493 Therapeutic Effects of Toll Like Receptor 9 Ligand CpG-ODN on Radiation Injury

Authors: Jianming Cai

Abstract:

Exposure to ionizing radiation causes severe damage to human body and an safe and effective radioprotector is urgently required for alleviating radiation damage. In 2008, flagellin, an agonist of TLR5, was found to exert radioprotective effects on radiation injury through activating NF-kB signaling pathway. From then, the radioprotective effects of TLR ligands has shed new lights on radiation protection. CpG-ODN is an unmethylated oligonucleotide which activates TLR9 signaling pathway. In this study, we demonstrated that CpG-ODN has therapeutic effects on radiation injuries induced by γ ray and 12C6+ heavy ion particles. Our data showed that CpG-ODN increased the survival rate of mice after whole body irradiation and increased the number of leukocytes as well as the bone marrow cells. CpG-ODN also alleviated radiation damage on intestinal crypt through regulating apoptosis signaling pathway including bcl2, bax, and caspase 3 etc. By using a radiation-induced pulmonary fibrosis model, we found that CpG-ODN could alleviate structural damage, within 20 week after whole–thorax 15Gy irradiation. In this model, Th1/Th2 imbalance induced by irradiation was also reversed by CpG-ODN. We also found that TGFβ-Smad signaling pathway was regulated by CpG-ODN, which accounts for the therapeutic effects of CpG-ODN in radiation-induced pulmonary injury. On another hand, for high LET radiation protection, we investigated protective effects of CpG-ODN against 12C6+ heavy ion irradiation and found that after CpG-ODN treatment, the apoptosis and cell cycle arrest induced by 12C6+ irradiation was reduced. CpG-ODN also reduced the expression of Bax and caspase 3, while increased the level of bcl2. Then we detected the effect of CpG-ODN on heavy ion induced immune dysfunction. Our data showed that CpG-ODN increased the survival rate of mice and also the leukocytes after 12C6+ irradiation. Besides, the structural damage of immune organ such as thymus and spleen was also alleviated by CpG-ODN treatment. In conclusion, we found that TLR9 ligand, CpG-ODN reduced radiation injuries in response to γ ray and 12C6+ heavy ion irradiation. On one hand, CpG-ODN inhibited the activation of apoptosis induced by radiation through regulating bcl2, bax and caspase 3. On another hand, through activating TLR9, CpG-ODN recruit MyD88-IRAK-TRAF6 complex, activating TAK1, IRF5 and NF-kB pathway, and thus alleviates radiation damage. This study provides novel insights into protection and therapy of radiation damages.

Keywords: TLR9, CpG-ODN, radiation injury, high LET radiation

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13492 Solar-Thermal-Electric Stirling Engine-Powered System for Residential Units

Authors: Florian Misoc, Cyril Okhio, Joshua Tolbert, Nick Carlin, Thomas Ramey

Abstract:

This project is focused on designing a Stirling engine system for a solar-thermal-electrical system that can supply electric power to a single residential unit. Since Stirling engines are heat engines operating any available heat source, is notable for its ability to generate clean and reliable energy without emissions. Due to the need of finding alternative energy sources, the Stirling engines are making a comeback with the recent technologies, which include thermal energy conservation during the heat transfer process. Recent reviews show mounting evidence and positive test results that Stirling engines are able to produce constant energy supply that ranges from 5kW to 20kW. Solar Power source is one of the many uses for Stirling engines. Using solar energy to operate Stirling engines is an idea considered by many researchers, due to the ease of adaptability of the Stirling engine. In this project, the Stirling engine developed was designed and tested to operate from biomass source of energy, i.e., wood pellets stove, during low solar radiation, with good results. A 20% efficiency of the engine was estimated, and 18% efficiency was measured, making it suitable and appropriate for residential applications. The effort reported was aimed at exploring parameters necessary to design, build and test a ‘Solar Powered Stirling Engine (SPSE)’ using Water (H₂O) as the Heat Transfer medium, with Nitrogen as the working gas that can reach or exceed an efficiency of 20%. The main objectives of this work consisted in: converting a V-twin cylinder air compressor into an alpha-type Stirling engine, construct a Solar Water Heater, by using an automotive radiator as the high-temperature reservoir for the Stirling engine, and an array of fixed mirrors that concentrate the solar radiation on the automotive radiator/high-temperature reservoir. The low-temperature reservoir is the surrounding air at ambient temperature. This work has determined that a low-cost system is sufficiently efficient and reliable. Off-the-shelf components have been used and estimates of the ability of the Engine final design to meet the electricity needs of small residence have been determined.

Keywords: stirling engine, solar-thermal, power inverter, alternator

Procedia PDF Downloads 278
13491 Combined Surface Tension and Natural Convection of Nanofluids in a Square Open Cavity

Authors: Habibis Saleh, Ishak Hashim

Abstract:

Combined surface tension and natural convection heat transfer in an open cavity is studied numerically in this article. The cavity is filled with water-{Cu} nanofluids. The left wall is kept at low temperature, the right wall at high temperature and the bottom and top walls are adiabatic. The top free surface is assumed to be flat and non--deformable. Finite difference method is applied to solve the dimensionless governing equations. It is found that the insignificant effect of adding the nanoparticles were obtained about $Ma_{bf}=250$.

Keywords: natural convection, marangoni convection, nanofluids, square open cavity

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13490 Mobile Games Applications Android-Based Physics Education to Improve Student Motivation and Interest in Learning Physics

Authors: Rizky Dwi A, Mikha Herlina Pi

Abstract:

Physics lessons for high school students, especially in Indonesia is less desirable because many people believe that physics is very difficult, especially the development of increasingly sophisticated era make online gaming more attractive many people especially school children with a variety of increasingly sophisticated gadgets. Therefore, if those two things combined to attract students in physics, the physics-based educational game android can motivate students' interest and understanding of the physics because while playing, they can also learn physics.

Keywords: education, game physics, interest, student's motivation

Procedia PDF Downloads 281
13489 Morphological Differentiation and Temporal Variability in Essential Oil Yield and Composition among Origanum vulgare ssp. hirtum L., Origanum onites L. and Origanum x intercedens from Ikaria Island (Greece)

Authors: A.Assariotakis, P. Vahamidis, P. Tarantilis, G. Economou

Abstract:

Greece, due to its geographical location and the particular climatic conditions, presents high biodiversity of Medicinal and Aromatic Plants. Among them, the genus Origanum not only presents a wide distribution, but it also has great economic importance. After extensive surveys in Ikaria Island (Greece), 3 species of the genus Origanum were identified, namely, Origanum vulgare ssp. hirtum (Greek oregano), Origanum onites (Turkish oregano) and Origanum x intercedens (hybrid), a naturally occurring hybrid between O. hirtum and O. onites. The purpose of this study was to determine their morphological as well as their temporal variability in essential oil yield and composition under field conditions. For this reason, a plantation of each species was created using vegetative propagation and was established at the experimental field of the Agricultural University of Athens (A.U.A.). From the establishment year and for the following two years (3 years of observations), several observations were taken during each growing season with the purpose of identifying the morphological differences among the studied species. Each year collected plant (at bloom stage) material was air-dried at room temperature in the shade. The essential oil content was determined by hydrodistillation using a Clevenger-type apparatus. The chemical composition of essential oils was investigated by Gas Chromatography-Mass Spectrometry (GC – MS). Significant differences were observed among the three oregano species in terms of plant height, leaf size, inflorescence features, as well as concerning their biological cycle. O. intercedens inflorescence presented more similarities with O. hirtum than with O. onites. It was found that calyx morphology could serve as a clear distinction feature between O. intercedens and O. hirtum. The calyx in O. hirtum presents five isometric teeth whereas in O. intercedens two high and three shorter. Essential oil content was significantly affected by genotype and year. O. hirtum presented higher essential oil content than the other two species during the first year of cultivation, however during the second year the hybrid (O. intercedens) recorded the highest values. Carvacrol, p-cymene and γ-terpinene were the main essential oil constituents of the three studied species. In O. hirtum carvacrol content varied from 84,28 - 93,35%, in O. onites from 86,97 - 91,89%, whereas in O. intercedens it was recorded the highest carvacrol content, namely from 89,25 - 97,23%.

Keywords: variability, oregano biotypes, essential oil, carvacrol

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13488 Investigation of the Excitotoxicity Pathways in Neuroblastoma Cells

Authors: Merve Colak, Gizem Donmez Yalcin

Abstract:

Glutamate has many neurological functions in the central nervous system and is found at high concentrations in the brain. Increased levels of glutamate in the neuronal space are toxic, causing neuron damage and death. This is called glutamate-induced excitotoxicity. Excitotoxicity is among the causes of many neurological diseases such as trauma, cerebral ischemia, epilepsy, Parkinson's Disease, Alzheimer's Disease. Since neuroblastoma cells are known to be excitotoxic, we propose that excitotoxicity can be studied in neuroblastoma cells. Excitotoxicity can be induced using kainic acid in neuroblastoma cells. Measuring the secretion of glutamate, excitotoxicity can be analyzed in neuroblastoma cells.

Keywords: glutamate, excitotoxicity, kainic acid, Sirt4

Procedia PDF Downloads 158
13487 Mechanism of Action of New Sustainable Flame Retardant Additives in Polyamide 6,6

Authors: I. Belyamani, M. K. Hassan, J. U. Otaigbe, W. R. Fielding, K. A. Mauritz, J. S. Wiggins, W. L. Jarrett

Abstract:

We have investigated the flame-retardant efficiency of special new phosphate glass (P-glass) compositions having different glass transition temperatures (Tg) on the processing conditions of polyamide 6,6 (PA6,6) and the final hybrid flame retardancy (FR). We have showed that the low Tg P glass composition (i.e., ILT 1) is a promising flame retardant for PA6,6 at a concentration of up to 15 wt. % compared to intermediate (IIT 3) and high (IHT 1) Tg P glasses. Cone calorimetry data showed that the ILT 1 decreased both the peak heat release rate and the total heat amount released from the PA6,6/ILT 1 hybrids, resulting in an efficient formation of a glassy char layer. These intriguing findings prompted to address several questions concerning the mechanism of action of the different P glasses studied. The general mechanism of action of phosphorous based FR additives occurs during the combustion stage by enhancing the morphology of the char and the thermal shielding effect. However, the present work shows that P glass based FR additives act during melt processing of PA6,6/P glass hybrids. Dynamic mechanical analysis (DMA) revealed that the Tg of PA6,6/ILT 1 was significantly shifted to a lower Tg (~65 oC) and another transition appeared at high temperature (~ 166 oC), thus indicating a strong interaction between PA6,6 and ILT 1. This was supported by a drop in the melting point and crystallinity of the PA6,6/ILT 1 hybrid material as detected by differential scanning calorimetry (DSC). The dielectric spectroscopic investigation of the networks’ molecular level structural variations (i.e. hybrids chain motion, Tg and sub-Tg relaxations) agreed very well with the DMA and DSC findings; it was found that the three different P glass compositions did not show any effect on the PA6,6 sub-Tg relaxations (related to the NH2 and OH chain end groups motions). Nevertheless, contrary to IIT 3 and IHT 1 based hybrids, the PA6,6/ILT 1 hybrid material showed an evidence of splitting the PA6,6 Tg relaxations into two peaks. Finally, the CPMAS 31P-NMR data confirmed the miscibility between ILT 1 and PA6,6 at the molecular level, as a much larger enhancement in cross-polarization for the PA6,6/15%ILT 1 hybrids was observed. It can be concluded that compounding low Tg P-glass (i.e. ILT 1) with PA6,6 facilitates hydrolytic chain scission of the PA6,6 macromolecules through a potential chemical interaction between phosphate and the alpha-Carbon of the amide bonds of the PA6,6, leading to better flame retardant properties.

Keywords: broadband dielectric spectroscopy, composites, flame retardant, polyamide, phosphate glass, sustainable

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13486 Superhydrophobic Materials: A Promising Way to Enhance Resilience of Electric System

Authors: M. Balordi, G. Santucci de Magistris, F. Pini, P. Marcacci

Abstract:

The increasing of extreme meteorological events represents the most important causes of damages and blackouts of the whole electric system. In particular, the icing on ground-wires and overheads lines, due to snowstorms or harsh winter conditions, very often gives rise to the collapse of cables and towers both in cold and warm climates. On the other hand, the high concentration of contaminants in the air, due to natural and/or antropic causes, is reflected in high levels of pollutants layered on glass and ceramic insulators, causing frequent and unpredictable flashover events. Overheads line and insulator failures lead to blackouts, dangerous and expensive maintenances and serious inefficiencies in the distribution service. Inducing superhydrophobic (SHP) properties to conductors, ground-wires and insulators, is one of the ways to face all these problems. Indeed, in some cases, the SHP surface can delay the ice nucleation time and decrease the ice nucleation temperature, preventing ice formation. Besides, thanks to the low surface energy, the adhesion force between ice and a superhydrophobic material are low and the ice can be easily detached from the surface. Moreover, it is well known that superhydrophobic surfaces can have self-cleaning properties: these hinder the deposition of pollution and decrease the probability of flashover phenomena. Here this study presents three different studies to impart superhydrophobicity to aluminum, zinc and glass specimens, which represent the main constituent materials of conductors, ground-wires and insulators, respectively. The route to impart the superhydrophobicity to the metallic surfaces can be summarized in a three-step process: 1) sandblasting treatment, 2) chemical-hydrothermal treatment and 3) coating deposition. The first step is required to create a micro-roughness. In the chemical-hydrothermal treatment a nano-scale metallic oxide (Al or Zn) is grown and, together with the sandblasting treatment, bring about a hierarchical micro-nano structure. By coating an alchilated or fluorinated siloxane coating, the surface energy decreases and gives rise to superhydrophobic surfaces. In order to functionalize the glass, different superhydrophobic powders, obtained by a sol-gel synthesis, were prepared. Further, the specimens were covered with a commercial primer and the powders were deposed on them. All the resulting metallic and glass surfaces showed a noticeable superhydrophobic behavior with a very high water contact angles (>150°) and a very low roll-off angles (<5°). The three optimized processes are fast, cheap and safe, and can be easily replicated on industrial scales. The anti-icing and self-cleaning properties of the surfaces were assessed with several indoor lab-tests that evidenced remarkable anti-icing properties and self-cleaning behavior with respect to the bare materials. Finally, to evaluate the anti-snow properties of the samples, some SHP specimens were exposed under real snow-fall events in the RSE outdoor test-facility located in Vinadio, western Alps: the coated samples delay the formation of the snow-sleeves and facilitate the detachment of the snow. The good results for both indoor and outdoor tests make these materials promising for further development in large scale applications.

Keywords: superhydrophobic coatings, anti-icing, self-cleaning, anti-snow, overheads lines

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13485 Community Structure Detection in Networks Based on Bee Colony

Authors: Bilal Saoud

Abstract:

In this paper, we propose a new method to find the community structure in networks. Our method is based on bee colony and the maximization of modularity to find the community structure. We use a bee colony algorithm to find the first community structure that has a good value of modularity. To improve the community structure, that was found, we merge communities until we get a community structure that has a high value of modularity. We provide a general framework for implementing our approach. We tested our method on computer-generated and real-world networks with a comparison to very known community detection methods. The obtained results show the effectiveness of our proposition.

Keywords: bee colony, networks, modularity, normalized mutual information

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13484 A Review of Toxic and Non-Toxic Cyanobacteria Species Occurrence in Water Supplies Destined for Maize Meal Production Process: A Case Study of Vhembe District

Authors: M. Mutoti, J. Gumbo, A. Jideani

Abstract:

Cyanobacteria or blue green algae have been part of the human diet for thousands of years. Cyanobacteria can multiply quickly in surface waters and form blooms when favorable conditions prevail, such as high temperature, intense light, high pH, and increased availability of nutrients, especially phosphorous and nitrogen, artificially released by anthropogenic activities. Consumption of edible cyanotoxins such as Spirulina may reduce risks of cataracts and age related macular degeneration. Sulfate polysaccharides exhibit antitumor, anticoagulant, anti-mutagenic, anti-inflammatory, antimicrobial, and even antiviral activity against HIV, herpes, and hepatitis. In humans, exposure to cyanotoxins can occur in various ways; however, the oral route is the most important. This is mainly through drinking water, or by eating contaminated foods; it may even involve ingesting water during recreational activities. This paper seeks to present a review on cyanobacteria/cyanotoxin contamination of water and food and implications for human health. In particular, examining the water quality used during maize seed that passes through mill grinding processes. In order to fulfil the objective, this paper starts with the theoretical framework on cyanobacteria contamination of food that will guide review of the present paper. A number of methods for decontaminating cyanotoxins in food is currently available. Therefore, physical, chemical, and biological methods for treating cyanotoxins are reviewed and compared. Furthermore, methods that are utilized for detecting and identifying cyanobacteria present in water and food were also informed in this review. This review has indicated various routes through which humans can be exposed to cyanotoxins. Accumulation of cyanotoxins, mainly microcystins, in food has raised an awareness of the importance of food as microcystins exposure route to human body. Therefore, this review demonstrates the importance of expanding research on cyanobacteria/cyanotoxin contamination of water and food for water treatment and water supply management, with focus on examining water for domestic use. This will help providing information regarding the prevention or minimization of contamination of water and food, and also reduction or removal of contamination through treatment processes and prevention of recontamination in the distribution system.

Keywords: biofilm, cyanobacteria, cyanotoxin, food contamination

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13483 Factors of Non-Conformity Behavior and the Emergence of a Ponzi Game in the Riba-Free (Interest-Free) Banking System of Iran

Authors: Amir Hossein Ghaffari Nejad, Forouhar Ferdowsi, Reza Mashhadi

Abstract:

In the interest-free banking system of Iran, the savings of society are in the form of bank deposits, and banks using the Islamic contracts, allocate the resources to applicants for obtaining facilities and credit. In the meantime, the central bank, with the aim of introducing monetary policy, determines the maximum interest rate on bank deposits in terms of macroeconomic requirements. But in recent years, the country's economic constraints with the stagflation and the consequence of the institutional weaknesses of the financial market of Iran have resulted in massive disturbances in the balance sheet of the banking system, resulting in a period of mismatch maturity in the banks' assets and liabilities and the implementation of a Ponzi game. This issue caused determination of the interest rate in long-term bank deposit contracts to be associated with non-observance of the maximum rate set by the central bank. The result of this condition was in the allocation of new sources of equipment to meet past commitments towards the old depositors and, as a result, a significant part of the supply of equipment was leaked out of the facilitating cycle and credit crunch emerged. The purpose of this study is to identify the most important factors affecting the occurrence of non-confirmatory financial banking behavior using data from 19 public and private banks of Iran. For this purpose, the causes of this non-confirmatory behavior of banks have been investigated using the panel vector autoregression method (PVAR) for the period of 2007-2015. Granger's causality test results suggest that the return of parallel markets for bank deposits, non-performing loans and the high share of the ratio of facilities to banks' deposits are all a cause of the formation of non-confirmatory behavior. Also, according to the results of impulse response functions and variance decomposition, NPL and the ratio of facilities to deposits have the highest long-term effect and also have a high contribution to explaining the changes in banks' non-confirmatory behavior in determining the interest rate on deposits.

Keywords: non-conformity behavior, Ponzi Game, panel vector autoregression, nonperforming loans

Procedia PDF Downloads 218
13482 A Secure Digital Signature Scheme with Fault Tolerance Based on the Improved RSA System

Authors: H. El-Kamchouchi, Heba Gaber, Fatma Ahmed, Dalia H. El-Kamchouchi

Abstract:

Fault tolerance and data security are two important issues in modern communication systems. In this paper, we propose a secure and efficient digital signature scheme with fault tolerance based on the improved RSA system. The proposed scheme for the RSA cryptosystem contains three prime numbers and overcome several attacks possible on RSA. By using the Chinese Reminder Theorem (CRT) the proposed scheme has a speed improvement on the RSA decryption side and it provides high security also.

Keywords: digital signature, fault tolerance, RSA, security analysis

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13481 Influence of Nanomaterials on the Properties of Shape Memory Polymeric Materials

Authors: Katielly Vianna Polkowski, Rodrigo Denizarte de Oliveira Polkowski, Cristiano Grings Herbert

Abstract:

The use of nanomaterials in the formulation of polymeric materials modifies their molecular structure, offering an infinite range of possibilities for the development of smart products, being of great importance for science and contemporary industry. Shape memory polymers are generally lightweight, have high shape recovery capabilities, they are easy to process and have properties that can be adapted for a variety of applications. Shape memory materials are active materials that have attracted attention due to their superior damping properties when compared to conventional structural materials. The development of methodologies capable of preparing new materials, which use graphene in their structure, represents technological innovation that transforms low-cost products into advanced materials with high added value. To obtain an improvement in the shape memory effect (SME) of polymeric materials, it is possible to use graphene in its composition containing low concentration by mass of graphene nanoplatelets (GNP), graphene oxide (GO) or other functionalized graphene, via different mixture process. As a result, there was an improvement in the SME, regarding the increase in the values of maximum strain. In addition, the use of graphene contributes to obtaining nanocomposites with superior electrical properties, greater crystallinity, as well as resistance to material degradation. The methodology used in the research is Systematic Review, scientific investigation, gathering relevant studies on influence of nanomaterials on the properties of shape memory polymeric, using the literature database as a source and study methods. In the present study, a systematic reviewwas performed of all papers published from 2014 to 2022 regarding graphene and shape memory polymeric througha search of three databases. This study allows for easy identification of themost relevant fields of study with respect to graphene and shape memory polymeric, as well as the main gaps to beexplored in the literature. The addition of graphene showed improvements in obtaining higher values of maximum deformation of the material, attributed to a possible slip between stacked or agglomerated nanostructures, as well as an increase in stiffness due to the increase in the degree of phase separation that results in a greater amount physical cross-links, referring to the formation of shortrange rigid domains.

Keywords: graphene, shape memory, smart materials, polymers, nanomaterials

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13480 From Waste Recycling to Waste Prevention by Households : Could Eco-Feedback Strategies Fill the Gap?

Authors: I. Dangeard, S. Meineri, M. Dupré

Abstract:

large body of research on energy consumption reveals that regular information on energy consumption produces a positive effect on behavior. The present research aims to test this feedback paradigm on waste management. A small-scale experiment on residual household waste was performed in a large french urban area, in partnership with local authorities, as part of the development of larger-scale project. A two-step door-to-door recruitment scheme led to 85 households answering a questionnaire. Among them, 54 accepted to participate in a study on waste (second step). Participants were then randomly assigned to one of the 3 experimental conditions : self-reported feedback on curbside waste, external feedback on waste weight based on information technologies, and no feedback for the control group. An additional control group was added, including households who were not requested to answer the questionnaire. Household residual waste was collected every week, and tags on curbside bins fed a database with waste weight of households. The feedback period lasted 14 weeks (february-may 2014). Quantitative data on waste weight were analysed, including these 14 weeks and the 7 previous weeks. Households were then contacted by phone in order to confirm the quantitative results. Regarding the recruitment questionnaire, results revealed high pro-environmental attitude on the NEP scale, high recycling behavior level and moderate level of source reduction behavior on the adapted 3R scale, but no statistical difference between the 3 experimental groups. Regarding the feedback manipulation paradigm, waste weight reveals important differences between households, but doesn't prove any statistical difference between the experimental conditions. Qualitative phone interviews confirm that recycling is a current practice among participants, whereas source reduction of waste is not, and mainly appears as a producer problem of packaging limitation. We conclude that triggering waste prevention behaviors among recycling households involves long-term feedback and should promote benchmarking, in order to clearly set waste reduction as an objective to be managed through feedback figures.

Keywords: eco-feedback, household waste, waste reduction, experimental research

Procedia PDF Downloads 392
13479 Non Destructive Ultrasound Testing for the Determination of Elastic Characteristics of AlSi7Zn3Cu2Mg Foundry Alloy

Authors: A. Hakem, Y. Bouafia

Abstract:

Characterization of materials used for various mechanical components is of great importance in their design. Several studies were conducted by various authors in order to improve their physical and/or chemical properties in general and mechanical or metallurgical properties in particular. The foundry alloy AlSi7Zn3Cu2Mg is one of the main components constituting the various mechanisms for the implementation of applications and various industrial projects. Obtaining a reliable product is not an easy task; several results proposed by different authors show sometimes results that can contradictory. Due to their high mechanical characteristics, these alloys are widely used in engineering. Silicon improves casting properties and magnesium allows heat treatment. It is thus possible to obtain various degrees of hardening and therefore interesting compromise between tensile strength and yield strength, on one hand, and elongation, on the other hand. These mechanical characteristics can be further enhanced by a series of mechanical treatments or heat treatments. Their light weight coupled with high mechanical characteristics, aluminum alloys are very much used in cars and aircraft industry. The present study is focused on the influence of heat treatments which cause significant micro structural changes, usually hardening by variation of annealing temperatures by increments of 10°C and 20°C on the evolution of the main elastic characteristics, the resistance, the ductility and the structural characteristics of AlSi7Zn3Cu2Mg foundry alloy cast in sand by gravity. These elastic properties are determined in three directions for each specimen of dimensions 200x150x20 mm³ by the ultrasonic method based on acoustic or elastic waves. The hardness, the micro hardness and the structural characteristics are evaluated by a non-destructive method. The aim of this work is to study the hardening ability of AlSi7Zn3Cu2Mg alloy by considering ten states. To improve the mechanical properties obtained with the raw casting, one should use heat treatment for structural hardening; the addition of magnesium is necessary to increase the sensitivity to this specific heat treatment: Treatment followed by homogenization which generates a diffusion of atoms in a substitution solid solution inside a hardening furnace at 500°C during 8h, followed immediately by quenching in water at room temperature 20 to 25°C, then an ageing process for 17h at room temperature and at different annealing temperature (150, 160, 170, 180, 190, 240, 200, 220 and 240°C) for 20h in an annealing oven. The specimens were allowed to cool inside the oven.

Keywords: aluminum, foundry alloy, magnesium, mechanical characteristics, silicon

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13478 Model Organic Ranikin Cycle Power Plant for Waste Heat Recovery in Olkaria-I Geothermal Power Plant

Authors: Haile Araya Nigusse, Hiram M. Ndiritu, Robert Kiplimo

Abstract:

Energy consumption is an indispensable component for the continued development of the human population. The global energy demand increases with development and population rise. The increase in energy demand, high cost of fossil fuels and the link between energy utilization and environmental impacts have resulted in the need for a sustainable approach to the utilization of the low grade energy resources. The Organic Rankine Cycle (ORC) power plant is an advantageous technology that can be applied in generation of power from low temperature brine of geothermal reservoirs. The power plant utilizes a low boiling organic working fluid such as a refrigerant or a hydrocarbon. Researches indicated that the performance of ORC power plant is highly dependent upon factors such as proper organic working fluid selection, types of heat exchangers (condenser and evaporator) and turbine used. Despite a high pressure drop, shell-tube heat exchangers have satisfactory performance for ORC power plants. This study involved the design, fabrication and performance assessment of the components of a model Organic Rankine Cycle power plant to utilize the low grade geothermal brine. Two shell and tube heat exchangers (evaporator and condenser) and a single stage impulse turbine have been designed, fabricated and the performance assessment of each component has been conducted. Pentane was used as a working fluid and hot water simulating the geothermal brine. The results of the experiment indicated that the increase in mass flow rate of hot water by 0.08 kg/s caused a rise in overall heat transfer coefficient of the evaporator by 17.33% and the heat transferred was increased by 6.74%. In the condenser, the increase of cooling water flow rate from 0.15 kg/s to 0.35 kg/s increased the overall heat transfer coefficient by 1.21% and heat transferred was increased by 4.26%. The shaft speed varied from 1585 to 4590 rpm as inlet pressure was varied from 0.5 to 5.0 bar and power generated was varying from 4.34 to 14.46W. The results of the experiments indicated that the performance of each component of the model Organic Rankine Cycle power plant operating at low temperature heat resources was satisfactory.

Keywords: brine, heat exchanger, ORC, turbine

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13477 Mobility Management for Pedestrian Accident Predictability and Mitigation Strategies Using Multiple

Authors: Oscar Norman Nekesa, Yoshitaka Kajita

Abstract:

Tom Mboya Street is a vital urban corridor within the spectrum of Nairobi city, it experiences high volumes of pedestrian and vehicular traffic. Despite past intervention measures to lessen this catastrophe, rates have remained high. This highlights significant safety concerns that need urgent attention. This study investigates the correlation and pedestrian accident predictability with significant independent variables using multiple linear regression to model to develop effective mobility management strategies for accident mitigation. The methodology involves collecting and analyzing data on pedestrian accidents and various related independent variables. Data sources include the National Transport and Safety Authority (NTSA), Kenya National Bureau of Statistics, and Nairobi City County records, covering five years. This study aims to investigate that traffic volumes (pedestrian and vehicle), Vehicular speed, human factors, illegal parking, policy issues, urban-land use, built environment, traffic signals conditions, inadequate lighting, and insufficient traffic control measures significantly have predictability with the rate of pedestrian accidents. Explanatory variables related to road design and geometry are significant in predictor models for the Tom Mboya Road link but less influential in junction along the 5 km stretch road models. The most impactful variable across all models was vehicular traffic flow. The study recommends infrastructural improvements, enhanced enforcement, and public awareness campaigns to reduce accidents and improve urban mobility. These insights can inform policy-making and urban planning to enhance pedestrian safety along the dense packed Tom Mboya Street and similar urban settings. The findings will inform evidence-based interventions to enhance pedestrian safety and improve urban mobility.

Keywords: multiple linear regression, urban mobility, traffic management, Nairobi, Tom Mboya street, infrastructure conditions., pedestrian safety, correlation and prediction

Procedia PDF Downloads 27
13476 Lipase-Mediated Formation of Peroxyoctanoic Acid Used in Catalytic Epoxidation of α-Pinene

Authors: N. Wijayati, Kusoro Siadi, Hanny Wijaya, Maggy Thenawijjaja Suhartono

Abstract:

This work describes the lipase-mediated synthesis of α-pinene oxide at ambient temperature. The immobilized lipase from Pseudomonas aeruginosa is used to generate peroxyoctanoic acid directly from octanoic acid and hydrogen peroxide. The peroxy acid formed is then applied for in situ oxidation of α-pinene. High conversion of α-pinene to α-pinene oxide (approximately 78%) was achieved when using 0,1 g enzim lipase, 6 mmol H2O2, dan 5 mmol octanoic acid. Various parameters affecting the conversion of α-pinene to α pinene oxide were studied.

Keywords: α-Pinene; P. aeruginosa; Octanoic acid

Procedia PDF Downloads 278
13475 Pesticide Residue Determination on Cumin Plant (Nigella orientalis L.) with LC-MS/MS and GC-MS

Authors: Nilda Ersoy, Sevinç Şener, Ayşe Yalçın Elidemir, Ebru Evcil, Ergün Döğen

Abstract:

In this study, pesticide residues were investigated in black cumin (Nigella orientalis L.) seeds grown in Turkey. GC-MS and LC-MS/MS analytical instruments are used in high precision when determining residue limits. A total of 100 pesticide active ingredients in LC-MS/MS devices have been performed in Nigella orientalis L. seeds samples. Also for the same aim, 103 pesticide active ingredients were analyzed in GC-MS. This study was conducted in 2012 and 2013. Sample residues were not found in detectable levels for two years.

Keywords: pesticide, residue, black cumin, Nigella orientalis L.

Procedia PDF Downloads 392
13474 Low Energy Technology for Leachate Valorisation

Authors: Jesús M. Martín, Francisco Corona, Dolores Hidalgo

Abstract:

Landfills present long-term threats to soil, air, groundwater and surface water due to the formation of greenhouse gases (methane gas and carbon dioxide) and leachate from decomposing garbage. The composition of leachate differs from site to site and also within the landfill. The leachates alter with time (from weeks to years) since the landfilled waste is biologically highly active and their composition varies. Mainly, the composition of the leachate depends on factors such as characteristics of the waste, the moisture content, climatic conditions, degree of compaction and the age of the landfill. Therefore, the leachate composition cannot be generalized and the traditional treatment models should be adapted in each case. Although leachate composition is highly variable, what different leachates have in common is hazardous constituents and their potential eco-toxicological effects on human health and on terrestrial ecosystems. Since leachate has distinct compositions, each landfill or dumping site would represent a different type of risk on its environment. Nevertheless, leachates consist always of high organic concentration, conductivity, heavy metals and ammonia nitrogen. Leachate could affect the current and future quality of water bodies due to uncontrolled infiltrations. Therefore, control and treatment of leachate is one of the biggest issues in urban solid waste treatment plants and landfills design and management. This work presents a treatment model that will be carried out "in-situ" using a cost-effective novel technology that combines solar evaporation/condensation plus forward osmosis. The plant is powered by renewable energies (solar energy, biomass and residual heat), which will minimize the carbon footprint of the process. The final effluent quality is very high, allowing reuse (preferred) or discharge into watercourses. In the particular case of this work, the final effluents will be reused for cleaning and gardening purposes. A minority semi-solid residual stream is also generated in the process. Due to its special composition (rich in metals and inorganic elements), this stream will be valorized in ceramic industries to improve the final products characteristics.

Keywords: forward osmosis, landfills, leachate valorization, solar evaporation

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13473 Influence of Initial Curing Time, Water Content and Apparent Water Content on Geopolymer Modified Sludge Generated in Landslide Area

Authors: Minh Chien Vu, Tomoaki Satomi, Hiroshi Takahashi

Abstract:

As being lack of sufficient strength to support the loading of construction as well as service life cause the clay content and clay mineralogy, soft and highly compressible soils (sludge) constitute a major problem in geotechnical engineering projects. Geopolymer, a kind of inorganic polymer, is a promising material with a wide range of applications and offers a lower level of CO₂ emissions than conventional Portland cement. However, the feasibility of geopolymer in term of modified the soft and highly compressible soil has not been received much attention due to the requirement of heat treatment for activating the fly ash component and the existence of high content of clay-size particles in the composition of sludge that affected on the efficiency of the reaction. On the other hand, the geopolymer modified sludge could be affected by other important factors such as initial curing time, initial water content and apparent water content. Therefore, this paper describes a different potential application of geopolymer: soil stabilization in landslide areas to adapt to the technical properties of sludge so that heavy machines can move on. Sludge condition process is utilized to demonstrate the possibility for stabilizing sludge using fly ash-based geopolymer at ambient curing condition ( ± 20 °C) in term of failure strength, strain and bulk density. Sludge conditioning is a process whereby sludge is treated with chemicals or various other means to improve the dewatering characteristics of sludge before applying in the construction area. The effect of initial curing time, water content and apparent water content on the modification of sludge are the main focus of this study. Test results indicate that the initial curing time has potential for improving failure strain and strength of modified sludge with the specific condition of soft soil. The result further shows that the initial water content over than 50% total mass of sludge could significantly lead to a decrease of strength performance of geopolymer-based modified sludge. The optimum apparent water content of geopolymer modified sludge is strongly influenced by the amount of geopolymer content and initial water content of sludge. The solution to minimize the effect of high initial water content will be considered deeper in the future.

Keywords: landslide, sludge, fly ash, geopolymer, sludge conditioning

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13472 The Evolution of Architecture through Digital: A Survey on Fashion Catwalk Becoming Digital

Authors: Valeria Minucciani, Maria Maddalena Margaria

Abstract:

While mathematical tools that make digital architecture possible are very sophisticated and advanced, theoretical development of digital architecture (intended as a discipline that integrates or replaces the real architecture) is not. The fashion show, that involves interiors architecture, exhibit design and scenography, has been exploiting for ten years the opportunities offered by digital technologies. To gain greater visibility and to reach a wider audience, high-level experimentations have been performed. The aim of this paper is in investigating, through the analysis of some cases of virtual fashion shows, the 'architectural' impact of the virtual conception of interior space.

Keywords: digital interiors, exhibit, fashion catwalk, architectural theory

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13471 Vibroacoustic Modulation of Wideband Vibrations and its Possible Application for Windmill Blade Diagnostics

Authors: Abdullah Alnutayfat, Alexander Sutin, Dong Liu

Abstract:

Wind turbine has become one of the most popular energy productions. However, failure of blades and maintenance costs evolve into significant issues in the wind power industry, so it is essential to detect the initial blade defects to avoid the collapse of the blades and structure. This paper aims to apply modulation of high-frequency blade vibrations by low-frequency blade rotation, which is close to the known Vibro-Acoustic Modulation (VAM) method. The high-frequency wideband blade vibration is produced by the interaction of the surface blades with the environment air turbulence, and the low-frequency modulation is produced by alternating bending stress due to gravity. The low-frequency load of rotational wind turbine blades ranges between 0.2-0.4 Hz and can reach up to 2 Hz for strong wind. The main difference between this study and previous ones on VAM methods is the use of a wideband vibration signal from the blade's natural vibrations. Different features of the vibroacoustic modulation are considered using a simple model of breathing crack. This model considers the simple mechanical oscillator, where the parameters of the oscillator are varied due to low-frequency blade rotation. During the blade's operation, the internal stress caused by the weight of the blade modifies the crack's elasticity and damping. The laboratory experiment using steel samples demonstrates the possibility of VAM using a probe wideband noise signal. A cycle load with a small amplitude was used as a pump wave to damage the tested sample, and a small transducer generated a wideband probe wave. The received signal demodulation was conducted using the Detecting of Envelope Modulation on Noise (DEMON) approach. In addition, the experimental results were compared with the modulation index (MI) technique regarding the harmonic pump wave. The wideband and traditional VAM methods demonstrated similar sensitivity for earlier detection of invisible cracks. Importantly, employing a wideband probe signal with the DEMON approach speeds up and simplifies testing since it eliminates the need to conduct tests repeatedly for various harmonic probe frequencies and to adjust the probe frequency.

Keywords: vibro-acoustic modulation, detecting of envelope modulation on noise, damage, turbine blades

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13470 Wear Resistance in Dry and Lubricated Conditions of Hard-anodized EN AW-4006 Aluminum Alloy

Authors: C. Soffritti, A. Fortini, E. Baroni, M. Merlin, G. L. Garagnani

Abstract:

Aluminum alloys are widely used in many engineering applications due to their advantages such ashigh electrical and thermal conductivities, low density, high strength to weight ratio, and good corrosion resistance. However, their low hardness and poor tribological properties still limit their use in industrial fields requiring sliding contacts. Hard anodizing is one of the most common solution for overcoming issues concerning the insufficient friction resistance of aluminum alloys. In this work, the tribological behavior ofhard-anodized AW-4006 aluminum alloys in dry and lubricated conditions was evaluated. Three different hard-anodizing treatments were selected: a conventional one (HA) and two innovative golden hard-anodizing treatments (named G and GP, respectively), which involve the sealing of the porosity of anodic aluminum oxides (AAO) with silver ions at different temperatures. Before wear tests, all AAO layers were characterized by scanning electron microscopy (VPSEM/EDS), X-ray diffractometry, roughness (Ra and Rz), microhardness (HV0.01), nanoindentation, and scratch tests. Wear tests were carried out according to the ASTM G99-17 standard using a ball-on-disc tribometer. The tests were performed in triplicate under a 2 Hz constant frequency oscillatory motion, a maximum linear speed of 0.1 m/s, normal loads of 5, 10, and 15 N, and a sliding distance of 200 m. A 100Cr6 steel ball10 mm in diameter was used as counterpart material. All tests were conducted at room temperature, in dry and lubricated conditions. Considering the more recent regulations about the environmental hazard, four bio-lubricants were considered after assessing their chemical composition (in terms of Unsaturation Number, UN) and viscosity: olive, peanut, sunflower, and soybean oils. The friction coefficient was provided by the equipment. The wear rate of anodized surfaces was evaluated by measuring the cross-section area of the wear track with a non-contact 3D profilometer. Each area value, obtained as an average of four measurements of cross-section areas along the track, was used to determine the wear volume. The worn surfaces were analyzed by VPSEM/EDS. Finally, in agreement with DoE methodology, a statistical analysis was carried out to identify the most influencing factors on the friction coefficients and wear rates. In all conditions, results show that the friction coefficient increased with raising the normal load. Considering the wear tests in dry sliding conditions, irrespective of the type of anodizing treatments, metal transfer between the mating materials was observed over the anodic aluminum oxides. During sliding at higher loads, the detachment of the metallic film also caused the delamination of some regions of the wear track. For the wear tests in lubricated conditions, the natural oils with high percentages of oleic acid (i.e., olive and peanut oils) maintained high friction coefficients and low wear rates. Irrespective of the type of oil, smallmicrocraks were visible over the AAO layers. Based on the statistical analysis, the type of anodizing treatment and magnitude of applied load were the main factors of influence on the friction coefficient and wear rate values. Nevertheless, an interaction between bio-lubricants and load magnitude could occur during the tests.

Keywords: hard anodizing treatment, silver ions, bio-lubricants, sliding wear, statistical analysis

Procedia PDF Downloads 151
13469 Regulatory Measures on Effective Nuclear Security and Safeguards System in Nigeria

Authors: Nnodi Chinweikpe Akelachi, Adebayo Oladini Kachollom Ifeoma

Abstract:

Insecurity and the possession of nuclear weapons for non-peaceful purposes constitute a major threat to global peace and security, and this undermines the capacity for sustainable development. In Nigeria, the threat of terrorism is a challenge to national stability. For over a decade, Nigeria has been faced with insecurity ranging from Boko-Haram terrorist groups, kidnapping and banditry. The threat exhibited by this non-state actor poses a huge challenge to nuclear and radiological high risks facilities in Nigeria. This challenge has resulted in the regulatory authority and International stakeholders formulating policies for a good mitigation strategy. This strategy is enshrined in formulated laws, regulations and guides like the repealed Nuclear Safety and Radiation Protection Act 19 of 1995 (Nuclear safety, Physical Security and Safeguards Bill), the Nigerian Physical Protection of Nuclear Material and Nuclear Facilities, and Nigerian Nuclear Safeguards Regulations of 2021. All this will help Nigeria’s effort to meet its national nuclear security and safeguards obligations. To further enhance the implementation of nuclear security and safeguards system, Nigeria has signed the Non-Proliferation Treaty (NPT) in 1970, the Comprehensive Safeguards Agreement (INFCIRC/358) in 1988, Additional Protocol in 2007 as well as the Convention on Physical Protection of Nuclear Material and its amendment in 2005. In view of the evolving threats by non-state actors in Nigeria, physical protection security upgrades are being implemented in nuclear and all high-risk radiological facilities through the support of the United States Department of Energy (US-DOE). Also, the IAEA has helped strengthen nuclear security and safeguard systems through the provision of technical assistance and capacity development. Efforts are being made to address some of the challenges identified in the cause of implementing the measures for effective nuclear security and safeguards systems in Nigeria. However, there are eminent challenges in the implementation of the measures within the security and systems in Nigeria. These challenges need to be addressed for an effective security and safeguard regime in Nigeria. This paper seeks to address the challenges encountered in implementing the regulatory and stakeholder measures for effective security and safeguards regime in Nigeria, amongst others.

Keywords: nuclear regulatory body, nuclear facilities and activities, international stakeholders, security and safeguards measures

Procedia PDF Downloads 112