Search results for: grafting modification

Authors: Thomas Folegot, Arnaud Levaufre, Léna Bourven, Nicolas Kermagoret, Alexis Caillard, Roger Gallou

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Concern for negative impacts of anthropogenic noise on the ocean’s ecosystems has increased over the recent decades. This concern leads to a similar increased willingness to regulate noise-generating activities, of which shipping is one of the most significant. Dealing with ship noise requires not only knowledge about the noise from individual ships, but also how the ship noise is distributed in time and space within the habitats of concern. Marine mammals, but also fish, sea turtles, larvae and invertebrates are mostly dependent on the sounds they use to hunt, feed, avoid predators, during reproduction to socialize and communicate, or to defend a territory. In the marine environment, sight is only useful up to a few tens of meters, whereas sound can propagate over hundreds or even thousands of kilometers. Directive 2008/56/EC of the European Parliament and of the Council of June 17, 2008 called the Marine Strategy Framework Directive (MSFD) require the Member States of the European Union to take the necessary measures to reduce the impacts of maritime activities to achieve and maintain a good environmental status of the marine environment. The Ocean-Planner is a web-based platform that provides to regulators, managers of protected or sensitive areas, etc. with a decision support tool that enable to anticipate and quantify the effectiveness of management measures in terms of reduction or modification the distribution of underwater noise, in response to Descriptor 11 of the MSFD and to the Marine Spatial Planning Directive. Based on the operational sound modelling tool Quonops Online Service, Ocean-Planner allows the user via an intuitive geographical interface to define management measures at local (Marine Protected Area, Natura 2000 sites, Harbors, etc.) or global (Particularly Sensitive Sea Area) scales, seasonal (regulation over a period of time) or permanent, partial (focused to some maritime activities) or complete (all maritime activities), etc. Speed limit, exclusion area, traffic separation scheme (TSS), and vessel sound level limitation are among the measures supported be the tool. Ocean Planner help to decide on the most effective measure to apply to maintain or restore the biodiversity and the functioning of the ecosystems of the coastal seabed, maintain a good state of conservation of sensitive areas and maintain or restore the populations of marine species.

Keywords: underwater noise, marine biodiversity, marine spatial planning, mitigation measures, prediction

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Authors: Taro Komori, Toshiki Gushi, Akihito Anzai, Taku Hirose, Kaoru Toko, Shinji Isogami, Takashi Suemasu

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Ferrimagnetic antiperovskite Mn₄₋ₓNiₓN thin film exhibits both small saturation magnetization and rather large perpendicular magnetic anisotropy (PMA) when x is small. Both of them are suitable features for application to current induced domain wall motion devices using spin transfer torque (STT). In this work, we successfully grew antiperovskite 30-nm-thick Mn₄₋ₓNiₓN epitaxial thin films on MgO(001) and STO(001) substrates by MBE in order to investigate their crystalline qualities and magnetic and magneto-transport properties. Crystalline qualities were investigated by X-ray diffraction (XRD). The magnetic properties were measured by vibrating sample magnetometer (VSM) at room temperature. Anomalous Hall effect was measured by physical properties measurement system. Both measurements were performed at room temperature. Temperature dependence of magnetization was measured by VSM-Superconducting quantum interference device. XRD patterns indicate epitaxial growth of Mn₄₋ₓNiₓN thin films on both substrates, ones on STO(001) especially have higher c-axis orientation thanks to greater lattice matching. According to VSM measurement, PMA was observed in Mn₄₋ₓNiₓN on MgO(001) when x ≤ 0.25 and on STO(001) when x ≤ 0.5, and MS decreased drastically with x. For example, MS of Mn₃.₉Ni₀.₁N on STO(001) was 47.4 emu/cm³. From the anomalous Hall resistivity (ρAH) of Mn₄₋ₓNiₓN thin films on STO(001) with the magnetic field perpendicular to the plane, we found out Mr/MS was about 1 when x ≤ 0.25, which suggests large magnetic domains in samples and suitable features for DW motion device application. In contrast, such square curves were not observed for Mn₄₋ₓNiₓN on MgO(001), which we attribute to difference in lattice matching. Furthermore, it’s notable that although the sign of ρAH was negative when x = 0 and 0.1, it reversed positive when x = 0.25 and 0.5. The similar reversal occurred for temperature dependence of magnetization. The magnetization of Mn₄₋ₓNiₓN on STO(001) increases with decreasing temperature when x = 0 and 0.1, while it decreases when x = 0.25. We considered that these reversals were caused by magnetic compensation which occurred in Mn₄₋ₓNiₓN between x = 0.1 and 0.25. We expect Mn atoms of Mn₄₋ₓNiₓN crystal have larger magnetic moments than Ni atoms do. The temperature dependence stated above can be explained if we assume that Ni atoms preferentially occupy the corner sites, and their magnetic moments have different temperature dependence from Mn atoms at the face-centered sites. At the compensation point, Mn₄₋ₓNiₓN is expected to show very efficient STT and ultrafast DW motion with small current density. What’s more, if angular momentum compensation is found, the efficiency will be best optimized. In order to prove the magnetic compensation, X-ray magnetic circular dichroism will be performed. Energy dispersive X-ray spectrometry is a candidate method to analyze the accurate composition ratio of samples.

Keywords: compensation, ferrimagnetism, Mn₄N, PMA

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Authors: E. Nemes-Nagy, E. Fogarasi, M. Croitoru, A. Nyárádi, K. Komlódi, S. Pál, A. Kovács, O. Kopácsy, R. Tripon, Z. Fazakas, C. Uzun, Z. Simon-Szabó, V. Balogh-Sămărghițan, E. Ernő Nagy, M. Szabó, M. Tilinca

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Intense oxidative stress, increased glycated hemoglobin and mineral imbalance represent risk factors for complications in diabetic patients. Cardiovascular complications are most common in these patients, including nephropathy. This study was conducted in 2015 at the Procardia Laboratory in Tîrgu Mureș, Romania on 40 type 2 diabetic adults. Routine biochemical tests were performed on the Konleab 20XTi analyzer (serum glucose, total cholesterol, LDL and HDL cholesterol, triglyceride, creatinine, urea). We also measured serum uric acid, magnesium and calcium concentration by photometric procedures, potassium, sodium and chloride by ion selective electrode, and chromium by atomic absorption spectrometry in a group of patients. Glycated hemoglobin (HbA1c) dosage was made by reflectometry. Urine analysis was performed using the HandUReader equipment. The level of oxidative stress was measured by serum malondialdehyde dosage using the thiobarbituric acid reactive substances method. MDRD (Modification of Diet in Renal Disease) formula was applied for calculation of creatinine-derived glomerular filtration rate. GraphPad InStat software was used for statistical analysis of the data. The diabetic subject included in the study presented high MDA concentrations, showing intense oxidative stress. Calcium was deficient in 5% of the patients, chromium deficiency was present in 28%. The atherogenic cholesterol fraction was elevated in 13% of the patients. Positive correlation was found between creatinine and MDRD-creatinine values (p<0.0001), 68% of the patients presented increased creatinine values. The majority of the diabetic patients had good control of their diabetes, having optimal HbA1c values, 35% of them presented fasting serum glucose over 120 mg/dl and 18% had glucosuria. Intense oxidative stress and mineral deficiencies can increase the risk of cardiovascular complications in diabetic patients in spite of their good metabolic balance. More than two third of the patients present biochemical signs of nephropathy, cystatin C dosage and microalbuminuria could reveal better the kidney disorder, but glomerular filtration rate calculation formulas are also useful for evaluation of renal function.

Keywords: cardiovascular risk, homocysteine, malondialdehyde, metformin, minerals, type 2 diabetes, vitamin B12

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Authors: Andrey A. Lipovskii, Alexey V. Redkov, Vyacheslav V. Rusan, Dmitry K. Tagantsev, Valentina V. Zhurikhina

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The presented research is related to the development of recently proposed technique of the formation of composite materials, like optical glass-ceramics, with predetermined structure and properties of the crystalline component. The technique is based on the control of the size and concentration of the crystalline grains using the phenomenon of glass-ceramics decrystallization (vitrification) induced by ion-exchange. This phenomenon was discovered and explained in the beginning of the 2000s, while related theoretical description was given in 2016 only. In general, the developed theory enables one to model the process and optimize the conditions of ion-exchange processing of glass-ceramics, which provide given properties of crystalline component, in particular, profile of the average size of the crystalline grains. The optimization is possible if one knows two dimensionless parameters of the theoretical model. One of them (β) is the value which is directly related to the solubility of crystalline component of the glass-ceramics in the glass matrix, and another (γ) is equal to the ratio of characteristic times of ion-exchange diffusion and crystalline grain dissolution. The presented study is dedicated to the development of experimental technique and simulation which allow determining these parameters. It is shown that these parameters can be deduced from the data on the space distributions of diffusant concentrations and average size of crystalline grains in the glass-ceramics samples subjected to ion-exchange treatment. Measurements at least at two temperatures and two processing times at each temperature are necessary. The composite material used was a silica-based glass-ceramics with crystalline grains of Li2OSiO2. Cubical samples of the glass-ceramics (6x6x6 mm3) underwent the ion exchange process in NaNO3 salt melt at 520 oC (for 16 and 48 h), 540 oC (for 8 and 24 h), 560 oC (for 4 and 12 h), and 580 oC (for 2 and 8 h). The ion exchange processing resulted in the glass-ceramics vitrification in the subsurface layers where ion-exchange diffusion took place. Slabs about 1 mm thick were cut from the central part of the samples and their big facets were polished. These slabs were used to find profiles of diffusant concentrations and average size of the crystalline grains. The concentration profiles were determined from refractive index profiles measured with Max-Zender interferometer, and profiles of the average size of the crystalline grains were determined with micro-Raman spectroscopy. Numerical simulation were based on the developed theoretical model of the glass-ceramics decrystallization induced by ion exchange. The simulation of the processes was carried out for different values of β and γ parameters under all above-mentioned ion exchange conditions. As a result, the temperature dependences of the parameters, which provided a reliable coincidence of the simulation and experimental data, were found. This ensured the adequate modeling of the process of the glass-ceramics decrystallization in 520-580 oC temperature interval. Developed approach provides a powerful tool for fine tuning of the glass-ceramics structure, namely, concentration and average size of crystalline grains.

Keywords: diffusion, glass-ceramics, ion exchange, vitrification

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Authors: Ali H. Daraji, Jack M. Hale, Ye Jianqiao

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With the extensive use of high specific strength structures to optimise the loading capacity and material cost in aerospace and most engineering applications, much effort has been expended to develop intelligent structures for active vibration reduction and structural health monitoring. These structures are highly flexible, inherently low internal damping and associated with large vibration and long decay time. The modification of such structures by adding lightweight piezoelectric sensors and actuators at efficient locations integrated with an optimal control scheme is considered an effective solution for structural vibration monitoring and controlling. The size and location of sensor and actuator are important research topics to investigate their effects on the level of vibration detection and reduction and the amount of energy provided by a controller. Several methodologies have been presented to determine the optimal location of a limited number of sensors and actuators for small-scale structures. However, these studies have tackled this problem directly, measuring the fitness function based on eigenvalues and eigenvectors achieved with numerous combinations of sensor/actuator pair locations and converging on an optimal set using heuristic optimisation techniques such as the genetic algorithms. This is computationally expensive for small- and large-scale structures subject to optimise a number of s/a pairs to suppress multiple vibration modes. This paper proposes an efficient method to determine optimal locations for a limited number of sensor/actuator pairs for active vibration reduction of a flexible structure based on finite element method and Hamilton’s principle. The current work takes the simplified approach of modelling a structure with sensors at all locations, subjecting it to an external force to excite the various modes of interest and noting the locations of sensors giving the largest average percentage sensors effectiveness measured by dividing all sensor output voltage over the maximum for each mode. The methodology was implemented for a cantilever plate under external force excitation to find the optimal distribution of six sensor/actuator pairs to suppress the first six modes of vibration. It is shown that the results of the optimal sensor locations give good agreement with published optimal locations, but with very much reduced computational effort and higher effectiveness. Furthermore, it is shown that collocated sensor/actuator pairs placed in these locations give very effective active vibration reduction using optimal linear quadratic control scheme.

Keywords: optimisation, plate, sensor effectiveness, vibration control

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Authors: Aayushi Somani, Siba P. Samal

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Three-dimensional (3D) meshes are data structures, which store geometric information of an object or scene, generally in the form of vertices and edges. Current technology in laser scanning and other geometric data acquisition technologies acquire high resolution sampling which leads to high resolution meshes. While high resolution meshes give better quality rendering and hence is used often, the processing, as well as storage of 3D meshes, is currently resource-intensive. At the same time, web applications for data processing have become ubiquitous owing to their accessibility. For 3D meshes, the advancement of 3D web technologies, such as WebGL, WebVR, has enabled high fidelity rendering of huge meshes. However, there exists a gap in ability to stream huge meshes to a native client and browser application due to high network latency. Also, there is an inherent delay of loading WebGL pages due to large and complex models. The focus of our work is to identify the challenges faced when such meshes are streamed into and processed on hand-held devices, owing to its limited resources. One of the solutions that are conventionally used in the graphics community to alleviate resource limitations is mesh compression. Our approach deals with a two-step approach for random accessible progressive compression and its parallel implementation. The first step includes partition of the original mesh to multiple sub-meshes, and then we invoke data parallelism on these sub-meshes for its compression. Subsequent threaded decompression logic is implemented inside the Web Browser Engine with modification of WebGL implementation in Chromium open source engine. This concept can be used to completely revolutionize the way e-commerce and Virtual Reality technology works for consumer electronic devices. These objects can be compressed in the server and can be transmitted over the network. The progressive decompression can be performed on the client device and rendered. Multiple views currently used in e-commerce sites for viewing the same product from different angles can be replaced by a single progressive model for better UX and smoother user experience. Can also be used in WebVR for commonly and most widely used activities like virtual reality shopping, watching movies and playing games. Our experiments and comparison with existing techniques show encouraging results in terms of latency (compressed size is ~10-15% of the original mesh), processing time (20-22% increase over serial implementation) and quality of user experience in web browser.

Keywords: 3D compression, 3D mesh, 3D web, chromium, client-server architecture, e-commerce, level of details, parallelization, progressive compression, WebGL, WebVR

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Authors: Muhammed Ertugrul Celoglu, Beyza Furtana, Mehmet Yilmaz, Baha Vural Kok

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Biomass, which is considered to be one of the largest renewable energy sources in the world, has a potential to be utilized as a bitumen additive after it is processed by a wide variety of thermochemical methods. Furthermore, biomasses are renewable in short amounts of time, and they possess a hydrocarbon structure. These characteristics of biomass promote their usability as additives. One of the most common ways to create materials with significant economic values from biomasses is the processes of pyrolysis. Pyrolysis is defined as the process of an organic matter’s thermochemical degradation (carbonization) at a high temperature and in an anaerobic environment. The resultant liquid substance at the end of the pyrolysis is defined as bio-oil, whereas the resultant solid substance is defined as biochar. Olive pomace is the resultant mildly oily pulp with seeds after olive is pressed and its oil is extracted. It is a significant source of biomass as the waste of olive oil factories. Because olive pomace is waste material, it could create problems just as other waste unless there are appropriate and acceptable areas of utilization. The waste material, which is generated in large amounts, is generally used as fuel and fertilizer. Generally, additive materials are used in order to improve the properties of bituminous binders, and these are usually expensive materials, which are produced chemically. The aim of this study is to investigate the usability of biochars obtained after subjecting olive pomace and smashed olive seeds, which are considered as waste materials, to pyrolysis as additives in bitumen modification. In this way, various ways of use will be provided for waste material, providing both economic and environmental benefits. In this study, olive pomace and smashed olive seeds were used as sources of biomass. Initially, both materials were ground and processed through a No.50 sieve. Both of the sieved materials were subjected to pyrolysis (carbonization) at 400 ℃. Following the process of pyrolysis, bio-oil and biochar were obtained. The obtained biochars were added to B160/220 grade pure bitumen at 10% and 15% rates and modified bitumens were obtained by mixing them in high shear mixtures at 180 ℃ for 1 hour at 2000 rpm. Pure bitumen and four different types of bitumen obtained as a result of the modifications were tested with penetration, softening point, rotational viscometer, and dynamic shear rheometer, evaluating the effects of additives and the ratios of additives. According to the test results obtained, both biochar modifications at both ratios provided improvements in the performance of pure bitumen. In the comparison of the test results of the binders modified with the biochars of olive pomace and smashed olive seed, it was revealed that there was no notable difference in their performances.

Keywords: bituminous binders, biochar, biomass, olive pomace, pomace, pyrolysis

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Authors: Kumlachew Zelalem Walle, Chun-Chen Yang

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Solid-state lithium metal batteries (SSLMBs) are considered promising candidates for next-generation energy storage devices due to their superior energy density and excellent safety. However, recent findings have shown that the formation of lithium (Li) dendrites in SSLMBs still exhibits a terrible growth ability, which makes the development of SSLMBs have to face the challenges posed by the Li dendrite problem. In this work, an inorganic/organic mixture coating material (g-C3N4/ZIF-8/PVDF) was used to modify the surface of lithium metal anode (LMA). Then the modified LMA (denoted as g-C₃N₄@Li) was assembled with lithium nafion (LiNf) coated commercial NCM811 (LiNf@NCM811) using a bilayer hybrid solid electrolyte (Bi-HSE) that incorporated 20 wt.% (vs. polymer) LiNf coated Li6.05Ga0.25La3Zr2O11.8F0.2 ([email protected]) filler faced to the positive electrode and the other layer with 80 wt.% (vs. polymer) filler content faced to the g-C₃N₄@Li. The garnet-type Li6.05Ga0.25La3Zr2O11.8F0.2 (LG0.25LZOF) solid electrolyte was prepared via co-precipitation reaction process from Taylor flow reactor and modified using lithium nafion (LiNf), a Li-ion conducting polymer. The Bi-HSE exhibited high ionic conductivity of 6.8  10–4 S cm–1 at room temperature, and a wide electrochemical window (0–5.0 V vs. Li/Li+). The coin cell was charged between 2.8 to 4.5 V at 0.2C and delivered an initial specific discharge capacity of 194.3 mAh g–1 and after 100 cycles it maintained 81.8% of its initial capacity at room temperature. The presence of a nano-sheet g-C3N4/ZIF-8/PVDF as a composite coating material on the LMA surface suppress the dendrite growth and enhance the compatibility as well as the interfacial contact between anode/electrolyte membrane. The g-C3N4@Li symmetrical cells incorporating this hybrid electrolyte possessed excellent interfacial stability over 1000 h at 0.1 mA cm–2 and a high critical current density (1 mA cm–2). Moreover, the in-situ formation of Li3N on the solid electrolyte interface (SEI) layer as depicted from the XPS result also improves the ionic conductivity and interface contact during the charge/discharge process. Therefore, these novel multi-layered fabrication strategies of hybrid/composite solid electrolyte membranes and modification of the LMA surface using mixed coating materials have potential applications in the preparation of highly safe high-voltage cathodes for SSLMBs.

Keywords: high-voltage cathodes, hybrid solid electrolytes, garnet, graphitic-carbon nitride (g-C3N4), ZIF-8 MOF

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Authors: Rebecca Bach, Evgenia Kanli, Nihat Kiziltoprak, Linda Hildebrand, Ulrich Knaack, Jens Schneider

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The building industry has a high demand for resources and at the same time is responsible for a significant amount of waste created worldwide. Today's building components need to contribute to the protection of natural resources without creating waste. This is defined in the product development phase and impacts the product’s degree of being cycle-oriented. Paper-based materials show advantage due to their renewable origin and their ability to incorporate different functions. Besides the ecological aspects like renewable origin and recyclability the main advantages of paper materials are its light-weight but stiff structure, the optimized production processes and good insulation values. The main deficits from building technology’s perspective are the material's vulnerability to humidity and water as well as inflammability. On material level, those problems can be solved by coatings or through material modification. On construction level intelligent setup and layering of a building component can improve and also solve these issues. The target of the present work is to provide an overview of developed building components and construction typologies mainly made from paper materials. The research is structured in four parts: (1) functions and requirements, (2) preselection of paper-based materials, (3) development of building components and (4) evaluation. As part of the research methodology at first the needs of the building sector are analyzed with the aim to define the main areas of application and consequently the requirements. Various paper materials are tested in order to identify to what extent the requirements are satisfied and determine potential optimizations or modifications, also in combination with other construction materials. By making use of the material’s potentials and solving the deficits on material and on construction level, building components and construction typologies are developed. The evaluation and the calculation of the structural mechanics and structural principals will show that different construction typologies can be derived. Profiles like paper tubes can be used at best for skeleton constructions. Massive structures on the other hand can be formed by plate-shaped elements like solid board or honeycomb. For insulation purposes corrugated cardboard or cellulose flakes have the best properties, while layered solid board can be applied to prevent inner condensation. Enhancing these properties by material combinations for instance with mineral coatings functional constructions mainly out of paper materials were developed. In summary paper materials offer a huge variety of possible applications in the building sector. By these studies a general base of knowledge about how to build with paper was developed and is to be reinforced by further research.

Keywords: construction typologies, cycle-oriented construction, innovative building material, paper materials, renewable resources

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Authors: Elsher Lawson-Boyd

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In the wake of the Human Genome Project, the life sciences have undergone some fascinating changes. In particular, conventional beliefs relating to gene expression are being challenged by advances in postgenomic sciences, especially by the field of epigenetics. Epigenetics is the modification of gene expression without changes in the DNA sequence. In other words, epigenetics dictates that gene expression, the process by which the instructions in DNA are converted into products like proteins, is not solely controlled by DNA itself. Unlike gene-centric theories of heredity that characterized much of the 20th Century (where the genes were considered as having almost god-like power to create life), gene expression in epigenetics insists on environmental ‘signals’ or ‘exposures’, a point that radically deviates from gene-centric thinking. Science and Technology Studies (STS) scholars have shown that epigenetic research is having vast implications for the ways in which chronic, non-communicable diseases are conceptualized, treated, and governed. However, to the author’s knowledge, there have not yet been any in-depth sociological engagements with neuroepigenetics that examine how the field is affecting mental health and trauma discourse. In this paper, the author discusses preliminary findings from a doctoral ethnographic study on neuroepigenetics, trauma, and embodiment. Specifically, this study investigates the kinds of causal relations neuroepigenetic researchers are making between experiences of trauma and the development of mental illnesses like complex post-traumatic stress disorder (PTSD), both throughout a human’s lifetime and across generations. Using qualitative interviews and nonparticipant observation, the author focuses on two public-facing research centers based in Melbourne: Florey Institute of Neuroscience and Mental Health (FNMH), and Murdoch Children’s Research Institute (MCRI). Preliminary findings indicate that a great deal of ambiguity characterizes this infant field, particularly when animal-model experiments are employed and the results are translated into human frameworks. Nevertheless, researchers at the FNMH and MCRI strongly suggest that adverse and traumatic life events have a significant effect on gene expression, especially when experienced during early development. Furthermore, they predict that neuroepigenetic research will have substantial implications for the ways in which mental illnesses like complex PTSD are diagnosed and treated. These preliminary findings shed light on why medical and health sociologists have good reason to be chiming in, engaging with and de-black-boxing ideations emerging from postgenomic sciences, as they may indeed have significant effects for vulnerable populations not only in Australia but other developing countries in the Global South.

Keywords: genetics, mental illness, neuroepigenetics, trauma

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Authors: Maritza Estela Garay-Rodriguez, Mirella Gutierrez-Arzaluz, Miguel Torres-Rodriguez, Violeta Mugica-Alvarez

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Arsenic is an element present in the earth's crust and is dispersed in the environment through natural processes and some anthropogenic activities. Naturally released into the environment through the weathering and erosion of sulphides mineral, some activities such as mining, the use of pesticides or wood preservatives potentially increase the concentration of arsenic in air, water, and soil. The natural arsenic release of a geological material is a threat to the world's drinking water sources. In aqueous phase is found in inorganic form, as arsenate and arsenite mainly, the contamination of groundwater by salts of this element originates what is known as endemic regional hydroarsenicism. The International Agency for Research on Cancer (IARC) categorizes the inorganic As within group I, as a substance with proven carcinogenic action for humans. It has been found the presence of As in groundwater in several countries such as Argentina, Mexico, Bangladesh, Canada and the United States. Regarding the concentration of arsenic in drinking water according to the World Health Organization (WHO) and the Environmental Protection Agency (EPA) establish maximum concentrations of 10 μg L⁻¹. In Mexico, in some states as Hidalgo, Morelos and Michoacán concentrations of arsenic have been found in bodies of water around 1000 μg L⁻¹, a concentration that is well above what is allowed by Mexican regulations with the NOM-127- SSA1-1994 that establishes a limit of 25 μg L⁻¹. Given this problem in Mexico, this research proposes the use of a natural Mexican zeolite (clinoptilolite type) native to the district of Etla in the central valley region of Oaxaca, as an adsorbent for the removal of arsenic. The zeolite was subjected to a conditioning with iron oxide by the precipitation-impregnation method with 0.5 M iron nitrate solution, in order to increase the natural adsorption capacity of this material. The removal of arsenic was carried out in a column with a fixed bed of conditioned zeolite, since it combines the advantages of a conventional filter with those of a natural adsorbent medium, providing a continuous treatment, of low cost and relatively easy to operate, for its implementation in marginalized areas. The zeolite was characterized by XRD, SEM/EDS, and FTIR before and after the arsenic adsorption tests, the results showed that the modification methods used are adequate to prepare adsorbent materials since it does not modify its structure, the results showed that with a particle size of 1.18 mm, an initial concentration of As (V) ions of 1 ppm, a pH of 7 and at room temperature, a removal of 98.7% was obtained with an adsorption capacity of 260 μg As g⁻¹ zeolite. The results obtained indicated that the conditioned zeolite is favorable for the elimination of arsenate in water containing up to 1000 μg As L⁻¹ and could be suitable for removing arsenate from pits of water.

Keywords: adsorption, arsenic, iron conditioning, natural zeolite

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Authors: Xinyu Wei, Mingming Peng, Kenji Kamiya, Eika Qian

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Iso-stearic acid as a saturated fatty acid with a branched chain shows a low pour point, high oxidative stability and great biodegradability. The industrial production of iso-stearic acid involves first isomerizing unsaturated fatty acids into branched-chain unsaturated fatty acids (BUFAs), followed by hydrogenating the branched-chain unsaturated fatty acids to obtain iso-stearic acid. However, the production yield of iso-stearic acid is reportedly less than 30%. In recent decades, extensive research has been conducted on branched fatty acids. Most research has replaced acidic clays with zeolites due to their high selectivity, good thermal stability, and renewability. It was reported that isomerization of unsaturated fatty acid occurred mainly inside the zeolite channel. In contrast, the production of by-products like dimer acid mainly occurs at acid sites outside the surface of zeolite. Further, the deactivation of catalysts is attributed to the pore blockage of zeolite. In the present study, micro/mesoporous ZSM-22 zeolites were developed. It is clear that the synthesis of a micro/mesoporous ZSM-22 zeolite is regarded as the ideal strategy owing to its ability to minimize coke formation. Different mesoporosities micro/mesoporous H-ZSM-22 zeolites were prepared through recrystallization of ZSM-22 using sodium hydroxide solution (0.2-1M) with cetyltrimethylammonium bromide template (CTAB). The structure, morphology, porosity, acidity, and isomerization performance of the prepared catalysts were characterized and evaluated. The dissolution and recrystallization process of the H-ZSM-22 microporous zeolite led to the formation of approximately 4 nm-sized mesoporous channels on the outer surface of the microporous zeolite, resulting in a micro/mesoporous material. This process increased the weak Brønsted acid sites at the pore mouth while reducing the total number of acid sites in ZSM-22. Finally, an activity test was conducted using oleic acid as a model compound in a fixed-bed reactor. The activity test results revealed that micro/mesoporous H-ZSM-22 zeolites exhibited a high isomerization activity, reaching >70% selectivity and >50% yield of BUFAs. Furthermore, the yield of oligomers was limited to less than 20%. This demonstrates that the presence of mesopores in ZSM-22 enhances contact between the feedstock and the active sites within the catalyst, thereby increasing catalyst activity. Additionally, a portion of the dissolved and recrystallized silica adhered to the catalyst's surface, covering the surface-active sites, which reduced the formation of oligomers. This study offers distinct insights into the production of iso-stearic acid using a fixed-bed reactor, paving the way for future research in this area.

Keywords: Iso-stearic acid, oleic acid, skeletal isomerization, micro/mesoporous, ZSM-22

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Authors: Prince S. Campbell, Janine B. Adams, Melusi Thwala, Opeoluwa Oyedele, Paula E. Melariri

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Schistosomiasis, often known as bilharzia, is a parasitic water-borne disease caused by trematode flatworms of the genus Schistosoma. Schistosomiasis infection and prevention have been found to be influenced by a range of socio-cultural risk factors, including human characteristics (e.g., gender, age, education, knowledge, attitude, and practices), as well as environmental and economic elements. Lack of awareness of the disease may also contribute to an individual's tendency to participate in behaviours or activities that heighten their susceptibility to infection. The current study assessed the community knowledge, attitude and practices (KAP) on schistosomiasis and implemented an educational intervention following pre-test interviews. A cross-sectional quasi-experimental research design was used in this quantitative study. Pre- and post-intervention interview format surveys were conducted using a structured questionnaire, targeting individuals aged 18–65 years residing within 5 km of select water bodies. The questionnaire contained 54 close-ended questions about schistosomiasis causes, transmission, and clinical symptoms and the participants were interviewed face-to-face in their homes. Data was captured on Question Pro and analyzed using Microsoft Office Excel 365 (2019) and R (version 4.3.1) software. Overall, 380 individuals completed the pre and post-intervention assessments; 194 and 185 were males (51.1%) and females (48.7%), respectively. A notable 91.3% of participants did not know about schistosomiasis in the pre-intervention phase; however, the mean post-intervention test score (9.4 ± 1.4) for knowledge among participants was higher than the pre-intervention test score (2.2 ± 2.1) indicating a good and improved knowledge of schistosomiasis among the participants. Furthermore, the paired samples t-test results demonstrated that the increase in knowledge levels was statistically significant (p<0.001). Also, the post-intervention improvement of both practice (p<0.001) and attitude (p<0.001) levels was statistically significant. A positive correlation (r=0.23, p<0.001) was found between knowledge and attitude in the pre-intervention stage. Knowledgeable participants had a more positive attitude towards obtaining medical assistance and disease prevention. Moreover, attitudes and practices correlated negatively (r=-0.13, p=0.013) post-intervention; hence, those with positive attitudes did not engage in risky water-related practices, which was the desired outcome. The educational intervention had a favourable impact on the KAP of the study population as the majority were able to recall the disease aetiology, symptoms, transmission pattern, and preventative measures three months post-intervention. Nevertheless, previous research has suggested that participants were unable to recall information about the disease following the intervention. Consequently, research should prioritize behavioural modification strategies that may result in a more persistent outcome in terms of the participants' knowledge, which could ultimately contribute to the development of long-term positive attitudes and practices.

Keywords: educational intervention, knowledge, attitudes and practices, schistosomiasis

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Authors: Luxi He, Tianfang Zhang, Zhengbin He, Songlin Yi

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Heat treatment has been widely recognized for its effectiveness in enhancing the physicochemical properties of wood, including hygroscopicity and dimensional stability. Nonetheless, the non-negligible volumetric shrinkage and loss of mechanical strength resulting from heat treatment may diminish the wood recovery and its product value. In this study, tung oil was used to alleviate heat-induced shrinkage and reduction in mechanical properties of wood during heat treatment. Tung oil was chosen as a modifier because it is a traditional Chinese plant oil that has been widely used for over a thousand years to protect wooden furniture and buildings due to its biodegradable and non-toxic properties. The effects of different heating media (air, tung oil) and their effective treatment parameters (temperature, duration) on the changes in the physical properties (morphological characteristics, pore structures, micromechanical properties), and chemical properties (chemical structures, chemical composition) of wood were investigated by using scanning electron microscopy, confocal laser scanning microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and dynamic vapor sorption. Meanwhile, the correlation between the mass changes and the color change, volumetric shrinkage, and hygroscopicity was also investigated. The results showed that the thermal degradation of wood cell wall components was the most important factor contributing to the changes in heat-induced shrinkage, color, and moisture adsorption of wood. In air-heat-treated wood samples, there was a significant correlation between mass change and heat-induced shrinkage, brightness, and moisture adsorption. However, the presence of impregnated tung oil in oil-heat-treated wood appears to disrupt these correlations among physical properties. The results of micromechanical properties demonstrated a significant decrease in elastic modulus following high-temperature heat treatment, which was mitigated by tung oil treatment. Chemical structure and compositional analyses indicated that the changes in chemical structure primarily stem from the degradation of hemicellulose and cellulose, and the presence of tung oil created an oxygen-insulating environment that slowed down this degradation process. Morphological observation results showed that tung oil permeated the wood structure and penetrated the cell walls through transportation channels, altering the micro-morphology of the cell wall surface, obstructing primary water passages (e.g., vessels and pits), and impeding the release of volatile degradation products as well as the infiltration and diffusion of water. In summary, tung oil treatment represents an environmentally friendly and efficient method for maximizing wood recovery and increasing product value. This approach holds significant potential for industrial applications in wood heat treatment.

Keywords: tung oil, heat treatment, physicochemical properties, wood cell walls

Procedia PDF Downloads 69

Authors: Joyce Cruz Ferraz Dutra, Marcele Fonseca Passos, Rubens Maciel Filho, Douglas Fernandes Barbin, Gustavo Mockaitis

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The search for alternatives to control hunger in the world, generated a major environmental problem. Intensive systems of fish production can cause an imbalance in the aquatic environment, triggering the phenomenon of eutrophication. Currently, there are many forms of growth control aquatic plants, such as mechanical withdrawal, however some difficulties arise for their final destination. The Egeria densa is a species of submerged aquatic macrophyte-rich in cellulose and low concentrations of lignin. By applying the concept of second generation energy, which uses lignocellulose for energy production, the reuse of these aquatic macrophytes (Egeria densa) in the biofuels production can turn an interesting alternative. In order to make lignocellulose sugars available for effective fermentation, it is important to use pre-treatments in order to separate the components and modify the structure of the cellulose and thus facilitate the attack of the microorganisms responsible for the fermentation. Therefore, the objective of this research work was to evaluate the structural and morphological transformations occurring in the biomass of aquatic macrophytes (E.densa) submitted to a thermal pretreatment. The samples were collected in an intensive fish growing farm, in the low São Francisco dam, in the northeastern region of Brazil. After collection, the samples were dried in a 65 0C ventilation oven and milled in a 5mm micron knife mill. A duplicate assay was carried, comparing the in natural biomass with the pretreated biomass with heat (MT). The sample (MT) was submitted to an autoclave with a temperature of 1210C and a pressure of 1.1 atm, for 30 minutes. After this procedure, the biomass was characterized in terms of degree of crystallinity and morphology, using X-ray diffraction (XRD) techniques and scanning electron microscopy (SEM), respectively. The results showed that there was a decrease of 11% in the crystallinity index (% CI) of the pretreated biomass, leading to the structural modification in the cellulose and greater presence of amorphous structures. Increases in porosity and surface roughness of the samples were also observed. These results suggest that biomass may become more accessible to the hydrolytic enzymes of fermenting microorganisms. Therefore, the morphological transformations caused by the thermal pretreatment may be favorable for a subsequent fermentation and, consequently, a higher yield of biofuels. Thus, the use of thermally pretreated aquatic macrophytes (E.densa) can be an environmentally, financially and socially sustainable alternative. In addition, it represents a measure of control for the aquatic environment, which can generate income (biogas production) and maintenance of fish farming activities in local communities.

Keywords: aquatics macrophyte, biofuels, crystallinity, morphology, pretreatment thermal

Procedia PDF Downloads 330

Authors: Ocsana Opris, Ildiko Lung, Maria L. Soran, Alexandra Ciorita, Lucian Copolovici

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The effects assessment of environmental stress factors on both crop and wild plants of nutritional value are a very important research topic. Continuously worldwide consumption of drugs leads to significant environmental pollution, thus generating environmental stress. Understanding the effects of the important drugs on plant composition and ultrastructural modification is still limited, especially at environmentally relevant concentrations. The aim of the present work was to investigate the influence of three non-steroidal anti-inflammatory drugs (NSAIDs) on chlorophylls content, carotenoids content, total polyphenols content, antioxidant capacity, and ultrastructure of orache (Atriplex patula L.) and spinach (Spinacia oleracea L.). All green leafy vegetables selected for this study were grown in controlled conditions and treated with solutions of different concentrations (0.1‒1 mg L⁻¹) of diclofenac, ibuprofen, and naproxen. After eight weeks of exposure of the plants to NSAIDs, the chlorophylls and carotenoids content were analyzed by high-performance liquid chromatography coupled with photodiode array and mass spectrometer detectors, total polyphenols and antioxidant capacity by ultraviolet-visible spectroscopy. Also, the ultrastructural analyses of the vegetables were performed using transmission electron microscopy in order to assess the influence of the selected NSAIDs on cellular organisms, mainly photosynthetic organisms (chloroplasts), energy supply organisms (mitochondria) and nucleus as a cellular metabolism coordinator. In comparison with the control plants, decreases in the content of chlorophylls were observed in the case of the Atriplex patula L. plants treated with ibuprofen (11-34%) and naproxen (25-52%). Also, the chlorophylls content from Spinacia oleracea L. was affected, the lowest decrease (34%) being obtained in the case of the treatment with naproxen (1 mg L⁻¹). Diclofenac (1 mg L⁻¹) affected the total polyphenols content (a decrease of 45%) of Atriplex patula L. and ibuprofen (1 mg L⁻¹) affected the total polyphenols content (a decrease of 20%) of Spinacia oleracea L. The results obtained also indicate a moderate reduction of carotenoids and antioxidant capacity in the treated plants, in comparison with the controls. The investigations by transmission electron microscopy demonstrated that the green leafy vegetables were affected by the selected NSAIDs. Thus, this research contributes to a better understanding of the adverse effects of these drugs on studied plants. Important to mention is that the dietary intake of these drugs contaminated plants, plants with important nutritional value, may also presume a risk to human health, but currently little is known about the fate of the drugs in plants and their effect on or risk to the ecosystem.

Keywords: abiotic stress, green leafy vegetables, pigments content, ultra structure

Procedia PDF Downloads 125

Authors: Z. M. Biyasheva, M. Zh. Tleubergenova, Y. A. Zaripova, A. L. Shakirov, V. V. Dyachkov

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In recent years, interest in ecogenetic and biomedical problems related to the effects on the population of radon and its daughter decay products has increased significantly. Of particular interest is the assessment of the consequence of irradiation at hazardous radon areas, which includes the Almaty region due to the large number of tectonic faults that enhance radon emanation. In connection with the foregoing, the purpose of this work was to study the genetic effects of exposure to supernormal radon doses on the alpha-radiation model. Irradiation does not affect the growth of the cell, but rather its ability to differentiate. In addition, irradiation can lead to somatic mutations, morphoses and modifications. These damages most likely occur from changes in the composition of the substances of the cell. Such changes are epigenetic since they affect the regulatory processes of ontogenesis. Variability in the expression of regulatory genes refers to conditional mutations that modify the formation of signs of intraspecific similarity. Characteristic features of these conditional mutations are the dominant type of their manifestation, phenotypic asymmetry and their instability in the generations. Currently, the terms “morphosis” and “modification” are used to describe epigenetic variability, which are maintained in Drosophila melanogaster cultures using linkaged X- chromosomes, and the mutant X-chromosome is transmitted along the paternal line. In this paper, we investigated the epigenetic effects of alpha particles, whose source in nature is mainly radon and its daughter decay products. In the experiment, an isotope of plutonium-238 (Pu²³⁸), generating radiation with an energy of about 5500 eV, was used as a source of alpha particles. In an experiment in the first generation (F₁), deformities or morphoses were found, which can be called "radiation syndromes" or mutations, the manifestation of which is similar to the pleiotropic action of genes. The proportion of morphoses in the experiment was 1.8%, and in control 0.4%. In this experiment, the morphoses in the flies of the first and second generation looked like black spots, or melanomas on different parts of the imago body; "generalized" melanomas; curled, curved wings; shortened wing; bubble on one wing; absence of one wing, deformation of thorax, interruption and violation of tergite patterns, disruption of distribution of ocular facets and bristles; absence of pigmentation of the second and third legs. Statistical analysis by the Chi-square method showed the reliability of the difference in experiment and control at P ≤ 0.01. On the basis of this, it can be considered that alpha particles, which in the environment are mainly generated by radon and its isotopes, have a mutagenic effect that manifests itself, mainly in the formation of morphoses or deformities.

Keywords: alpha-radiation, genotoxicity, morphoses, radioecology, radon

Procedia PDF Downloads 152

Authors: Aipeng Zhu, Yun Zhang

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The growing grievous environment problems together with the exhaustion of energy resources put urgent demands for developing high energy density. Considering the factors including capacity, resource and environment, Manganese-based lithium-rich layer-structured cathode materials xLi₂MnO₃⋅(1-x)LiMO₂ (M = Ni, Co, Mn, and other metals) are drawing increasing attention due to their high reversible capacities, high discharge potentials, and low cost. They are expected to be one type of the most promising cathode materials for the next-generation Li-ion batteries (LIBs) with higher energy densities. Unfortunately, their commercial applications are hindered with crucial drawbacks such as poor rate performance, limited cycle life and continuous falling of the discharge potential. With decades of extensive studies, significant achievements have been obtained in improving their cyclability and rate performances, but they cannot meet the requirement of commercial utilization till now. One major problem for lithium-rich layer-structured cathode materials (LLOs) is the side reaction during cycling, which leads to severe surface degradation. In this process, the metal ions can dissolve in the electrolyte, and the surface phase change can hinder the intercalation/deintercalation of Li ions and resulting in low capacity retention and low working voltage. To optimize the LLOs cathode material, the surface coating is an efficient method. Considering the price and stability, Al₂O₃ was used as a coating material in the research. Meanwhile, due to the low initial Coulombic efficiency (ICE), the pristine LLOs was pretreated by KMnO₄ to increase the ICE. The precursor was prepared by a facile coprecipitation method. The as-prepared precursor was then thoroughly mixed with Li₂CO₃ and calcined in air at 500℃ for 5h and 900℃ for 12h to produce Li₁.₂[Ni₀.₂Mn₀.₆]O₂ (LNMO). The LNMO was then put into 0.1ml/g KMnO₄ solution stirring for 3h. The resultant was filtered and washed with water, and dried in an oven. The LLOs obtained was dispersed in Al(NO₃)₃ solution. The mixture was lyophilized to confer the Al(NO₃)₃ was uniformly coated on LLOs. After lyophilization, the LLOs was calcined at 500℃ for 3h to obtain LNMO@LMO@ALO. The working electrodes were prepared by casting the mixture of active material, acetylene black, and binder (polyvinglidene fluoride) dissolved in N-methyl-2-pyrrolidone with a mass ratio of 80: 15: 5 onto an aluminum foil. The electrochemical performance tests showed that the multiple surface modified materials had a higher initial Coulombic efficiency (84%) and better capacity retention (91% after 100 cycles) compared with that of pristine LNMO (76% and 80%, respectively). The modified material suggests that the KMnO₄ pretreat and Al₂O₃ coating can increase the ICE and cycling stability.

Keywords: Li-rich materials, surface coating, lithium ion batteries, Al₂O₃

Procedia PDF Downloads 133

Authors: Sihem Bazid, Meriem El Kolli, Aicha Medjahed

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Proteins and polysaccharides are the two types of biopolymers most frequently used in the food industry to control the mechanical properties and structural stability and organoleptic properties of the products. The textural and structural properties of these two types of blend polymers depend on their interaction and their ability to form organized structures. From an industrial point of view, a better understanding of mixtures protein / polysaccharide is an important issue since they are already heavily involved in processed food. It is in this context that we have chosen to work on a model system composed of a fibrous protein mixture (gelatin)/anionic polysaccharide (sodium carboxymethylcellulose). Gelatin, one of the most popular biopolymers, is widely used in food, pharmaceutical, cosmetic and photographic applications, because of its unique functional and technological properties. Sodium Carboxymethylcellulose (NaCMC) is an anionic linear polysaccharide derived from cellulose. It is an important industrial polymer with a wide range of applications. The functional properties of this anionic polysaccharide can be modified by the presence of proteins with which it might interact. Another factor may also manage the interaction of protein-polysaccharide mixtures is the triple helix of the gelatin. Its complex synthesis method results in an extracellular assembly containing several levels. Collagen can be in a soluble state or associate into fibrils, which can associate in fiber. Each level corresponds to an organization recognized by the cellular and metabolic system. Gelatin allows this approach, the formation of gelatin gel has triple helical folding of denatured collagen chains, this gel has been the subject of numerous studies, and it is now known that the properties depend only on the rate of triple helices forming the network. Chemical modification of this system is quite controlled. Observe the dynamics of the triple helix may be relevant in understanding the interactions involved in protein-polysaccharides mixtures. Gelatin is central to any industrial process, understand and analyze the molecular dynamics induced by the triple helix in the transitions gelatin, can have great economic importance in all fields and especially the food. The goal is to understand the possible mechanisms involved depending on the nature of the mixtures obtained. From a fundamental point of view, it is clear that the protective effect of NaCMC on gelatin and conformational changes of the α helix are strongly influenced by the nature of the medium. Our goal is to minimize the maximum the α helix structure changes to maintain more stable gelatin and protect against denaturation that occurs during such conversion processes in the food industry. In order to study the nature of interactions and assess the properties of mixtures, polarimetry was used to monitor the optical parameters and to assess the rate of helicity gelatin.

Keywords: gelatin, sodium carboxymethylcellulose, interaction gelatin-NaCMC, the rate of helicity, polarimetry

Procedia PDF Downloads 313

Authors: Hamed Khosravi, Reza Eslami-Farsani

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Increased interest in lightweight and efficient structural components has created the need for selecting materials with improved mechanical properties. To do so, composite materials are being widely used in many applications, due to durability, high strength and modulus, and low weight. Among the various composite structures, grid-stiffened structures are extensively considered in various aerospace and aircraft applications, because of higher specific strength and stiffness, higher impact resistance, superior load-bearing capacity, easy to repair, and excellent energy absorption capability. Although there are a good number of publications on the design aspects and fabrication of grid structures, little systematic work has been reported on their material modification to improve their properties, to our knowledge. Therefore, the aim of this research is to study the reinforcing effect of silica nanoparticles on the flexural properties of epoxy/E-glass isogrid panels under three-point bending test. Samples containing 0, 1, 3, and 5 wt.% of the silica nanoparticles, with 44 and 48 vol.% of the glass fibers in the ribs and skin components respectively, were fabricated by using a manual filament winding method. Ultrasonic and mechanical routes were employed to disperse the nanoparticles within the epoxy resin. To fabricate the ribs, the unidirectional fiber rovings were impregnated with the matrix mixture (epoxy + nanoparticles) and then laid up into the grooves of a silicone mold layer-by-layer. At once, four plies of woven fabrics, after impregnating into the same matrix mixture, were layered on the top of the ribs to produce the skin part. In order to conduct the ultimate curing and to achieve the maximum strength, the samples were tested after 7 days of holding at room temperature. According to load-displacement graphs, the bellow trend was observed for all of the samples when loaded from the skin side; following an initial linear region and reaching a load peak, the curve was abruptly dropped and then showed a typical absorbed energy region. It would be worth mentioning that in these structures, a considerable energy absorption was observed after the primary failure related to the load peak. The results showed that the flexural properties of the nanocomposite samples were always higher than those of the nanoparticle-free sample. The maximum enhancement in flexural maximum load and energy absorption was found to be for the incorporation of 3 wt.% of the nanoparticles. Furthermore, the flexural stiffness was continually increased by increasing the silica loading. In conclusion, this study suggested that the addition of nanoparticles is a promising method to improve the flexural properties of grid-stiffened fibrous composite structures.

Keywords: grid-stiffened composite structures, nanocomposite, three point flexural test , energy absorption

Procedia PDF Downloads 341

Authors: Natia Jalagonia, Jimsher Maisuradze, Karlo Barbakadze, Tinatin Kuchukhidze

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At present intensive scientific researches of ceramics, cermets and metal alloys have been conducted for improving materials physical-mechanical characteristics. In purpose of increasing impact strength of ceramics based on alumina, simple method of graphene homogenization was developed. Homogeneous distribution of graphene (homogenization) in pressing composite became possible through the connection of functional groups of graphene oxide (-OH, -COOH, -O-O- and others) and alumina superficial OH groups with aluminum organic compounds. These two components connect with each other with -O-Al–O- bonds, and by their thermal treatment (300–500°C), graphene and alumina phase are transformed. Thus, choosing of aluminum organic compounds for modification is stipulated by the following opinion: aluminum organic compounds fragments fixed on graphene and alumina finally are transformed into an integral part of the matrix. By using of other elements as modifier on the matrix surface (Al2O3) other phases are transformed, which change sharply physical-mechanical properties of ceramic composites, for this reason, effect caused by the inclusion of graphene will be unknown. Fixing graphene fragments on alumina surface by alumoorganic compounds result in new type graphene-alumina complex, in which these two components are connected by C-O-Al bonds. Part of carbon atoms in graphene oxide are in sp3 hybrid state, so functional groups (-OH, -COOH) are located on both sides of graphene oxide layer. Aluminum organic compound reacts with graphene oxide at the room temperature, and modified graphene oxide is obtained: R2Al-O-[graphene]–COOAlR2. Remaining Al–C bonds also reacts rapidly with surface OH groups of alumina. In a result of these process, pressing powdery composite [Al2O3]-O-Al-O-[graphene]–COO–Al–O–[Al2O3] is obtained. For the purpose, graphene oxide suspension in dry toluene have added alumoorganic compound Al(iC4H9)3 in toluene with equimolecular ratio. Obtained suspension has put in the flask and removed solution in a rotary evaporate presence nitrogen atmosphere. Obtained powdery have been researched and used to consolidation of ceramic materials based on alumina. Ceramic composites are obtained in high temperature vacuum furnace with different temperature and pressure conditions. Received ceramics do not have open pores and their density reaches 99.5 % of TD. During the work, the following devices have been used: High temperature vacuum furnace OXY-GON Industries Inc (USA), device of spark-plasma synthesis, induction furnace, Electronic Scanning Microscopes Nikon Eclipse LV 150, Optical Microscope NMM-800TRF, Planetary mill Pulverisette 7 premium line, Shimadzu Dynamic Ultra Micro Hardness Tester DUH-211S, Analysette 12 Dynasizer and others.

Keywords: graphene oxide, alumo-organic, ceramic

Procedia PDF Downloads 308

Authors: Sajana Suwal, Ganesh R. Nhemafuki

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Evaluation of ground response under earthquake shaking is crucial in geotechnical earthquake engineering. Damage due to seismic excitation is mainly correlated to local geological and geotechnical conditions. It is evident from the past earthquakes (e.g. 1906 San Francisco, USA, 1923 Kanto, Japan) that the local geology has strong influence on amplitude and duration of ground motions. Since then significant studies has been conducted on ground motion amplification revealing the importance of influence of local geology on ground. Observations from the damaging earthquakes (e.g. Nigata and San Francisco, 1964; Irpinia, 1980; Mexico, 1985; Kobe, 1995; L’Aquila, 2009) divulged that non-uniform damage pattern, particularly in soft fluvio-lacustrine deposit is due to the local amplification of seismic ground motion. Non-uniform damage patterns are also observed in Kathmandu Valley during 1934 Bihar Nepal earthquake and recent 2015 Gorkha earthquake seemingly due to the modification of earthquake ground motion parameters. In this study, site effects resulting from amplification of soft soil in Kathmandu are presented. A large amount of subsoil data was collected and used for defining the appropriate subsoil model for the Kathamandu valley. A comparative study of one-dimensional total-stress equivalent linear and non-linear site response is performed using four strong ground motions for six sites of Kathmandu valley. In general, one-dimensional (1D) site-response analysis involves the excitation of a soil profile using the horizontal component and calculating the response at individual soil layers. In the present study, both equivalent linear and non-linear site response analyses were conducted using the computer program DEEPSOIL. The results show that there is no significant deviation between equivalent linear and non-linear site response models until the maximum strain reaches to 0.06-0.1%. Overall, it is clearly observed from the results that non-linear site response model perform better as compared to equivalent linear model. However, the significant deviation between two models is resulted from other influencing factors such as assumptions made in 1D site response, lack of accurate values of shear wave velocity and nonlinear properties of the soil deposit. The results are also presented in terms of amplification factors which are predicted to be around four times more in case of non-linear analysis as compared to equivalent linear analysis. Hence, the nonlinear behavior of soil prevails the urgent need of study of dynamic characteristics of the soft soil deposit that can specifically represent the site-specific design spectra for the Kathmandu valley for building resilient structures from future damaging earthquakes.

Keywords: deep soil, equivalent linear analysis, non-linear analysis, site response

Procedia PDF Downloads 291

Authors: Sergio A. Navarro Tuch, Martin Rogelio Bustamante Bello, Leopoldo Julian Lechuga Lopez

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In recent years, Mexico’s population has seen a rise of different physiological and mental negative states. Two main consequences of this problematic are deficient work performance and high levels of stress generating and important impact on a person’s physical, mental and emotional health. Several approaches, such as the use of audiovisual stimulus to induce emotions and modify a person’s emotional state, can be applied in an effort to decreases these negative effects. With the use of different non-invasive physiological sensors such as EEG, luminosity and face recognition we gather information of the subject’s current emotional state. In a controlled environment, a subject is shown a series of selected images from the International Affective Picture System (IAPS) in order to induce a specific set of emotions and obtain information from the sensors. The raw data obtained is statistically analyzed in order to filter only the specific groups of information that relate to a subject’s emotions and current values of the physical variables in the controlled environment such as, luminosity, RGB light color, temperature, oxygen level and noise. Finally, a neural network based control algorithm is given the data obtained in order to feedback the system and automate the modification of the environment variables and audiovisual content shown in an effort that these changes can positively alter the subject’s emotional state. During the research, it was found that the light color was directly related to the type of impact generated by the audiovisual content on the subject’s emotional state. Red illumination increased the impact of violent images and green illumination along with relaxing images decreased the subject’s levels of anxiety. Specific differences between men and women were found as to which type of images generated a greater impact in either gender. The population sample was mainly constituted by college students whose data analysis showed a decreased sensibility to violence towards humans. Despite the early stage of the control algorithm, the results obtained from the population sample give us a better insight into the possibilities of emotional domotics and the applications that can be created towards the improvement of performance in people’s lives. The objective of this research is to create a positive impact with the application of technology to everyday activities; nonetheless, an ethical problem arises since this can also be applied to control a person’s emotions and shift their decision making.

Keywords: data analysis, emotional domotics, performance improvement, neural network

Procedia PDF Downloads 140

Authors: Mohammad Hossein Pazandeh, Monir Doudi, Sona Rostampour Yasouri

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—Results The prudent administration of antibiotics aims to avoid the side effects and the microbes' resistance to antibiotics. An approach developing methods of local administration of antibiotics is especially required for localized infections caused by bacterial colonization of medical devices or implant materials. Among the wide variety of materials used as drug delivery systems, bioactive glasses (BG) have large utilization in regenerative medicine . firstly, the production of bioactive glass/nickel oxide/tin dioxide nanocomposite using sol-gel method, and then, the controlled release of imipenem from the double metal oxide/bioactive glass nanocomposite, and finally, the investigation of the antibacterial property of the nanocomposite. against a number of implant-related infectious agents. In this study, BG/SnO2 and BG/NiO single systema with different metal oxide present and BG/NiO/SnO2 nanocomposites were synthesized by sol-gel as drug carriers for tetracycline and imepinem. These two antibiotics were widely used for osteomyelitis because of its favorable penetration and bactericidal effect on all the probable osteomyelitis pathogens. The antibacterial activity of synthesized samples were evaluated against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa as bacteria model using disk diffusion method. The BG modification using metal oxides results to antibacterial property of samples containing metal oxide with highest efficiency for nancomposite. bioactivity of all samples was assessed by determining the surface morphology, structural and composition changes using scanning electron microscopy (SEM), FTIR and X-ray diffraction (XRD) spectroscopy, respectively, after soaking in simulated body fluid (SBF) for 28 days. The hydroxyapatite formation was clearly observed as a bioactivity measurement. Then, BG nanocomposite sample was loaded using two antibiotics, separately and their release profiles were studied. The BG nancomposite sample was shown the slow and continuous drug releasing for a period of 72 hours which is desirable for a drug delivery system. The loaded antibiotic nanocomposite sample retaining antibacterial property and showing inactivation effect against bacteria under test. The modified bioactive glass forming hydroxyapatite with controlled release drug and effective against bacterial infections can be introduced as scaffolds for bone implants after clinical trials for biomedical applications . Considering the formation of biofilm by infectious bacteria after sticking on the surfaces of implants, medical devices, etc. Also, considering the complications of traditional methods, solving the problems caused by the above-mentioned microorganisms in technical and biomedical industries was one of the necessities of this research.

Keywords: antibacterial, bioglass, drug delivery system, sol- gel

Procedia PDF Downloads 60

Authors: Diego F. Camacho, Cristian J. Mejia, Carlos Duque-Daza

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The recent widespread use of Unmanned Aerial Vehicles (UAVs) has fueled a renewed interest in efficiency and performance of airfoils, particularly for applications at low and moderate Reynolds numbers, typical of this kind of vehicles. Most of previous efforts in the aeronautical industry, regarding aerodynamic efficiency, had been focused on high Reynolds numbers applications, typical of commercial airliners and large size aircrafts. However, in order to increase the levels of efficiency and to boost the performance of these UAV, it is necessary to explore new alternatives in terms of airfoil design and application of drag reduction techniques. The objective of the present work is to carry out the analysis and comparison of performance levels between a standard NACA0012 profile against another one featuring a wall protuberance or surface perturbation. A computational model, based on the finite volume method, is employed to evaluate the effect of the presence of geometrical distortions on the wall. The performance evaluation is achieved in terms of variations of drag and lift coefficients for the given profile. In particular, the aerodynamic performance of the new design, i.e. the airfoil with a surface perturbation, is examined under conditions of incompressible and subsonic flow in transient state. The perturbation considered is a shaped protrusion prescribed as a small surface deformation on the top wall of the aerodynamic profile. The ultimate goal by including such a controlled smooth artificial roughness was to alter the turbulent boundary layer. It is shown in the present work that such a modification has a dramatic impact on the aerodynamic characteristics of the airfoil, and if properly adjusted, in a positive way. The computational model was implemented using the unstructured, FVM-based open source C++ platform OpenFOAM. A number of numerical experiments were carried out at Reynolds number 5x104, based on the length of the chord and the free-stream velocity, and angles of attack 6° and 12°. A Large Eddy Simulation (LES) approach was used, together with the dynamic Smagorinsky approach as subgrid scale (SGS) model, in order to account for the effect of the small turbulent scales. The impact of the surface perturbation on the performance of the airfoil is judged in terms of changes in the drag and lift coefficients, as well as in terms of alterations of the main characteristics of the turbulent boundary layer on the upper wall. A dramatic change in the whole performance can be appreciated, including an arguably large level of lift-to-drag coefficient ratio increase for all angles and a size reduction of laminar separation bubble (LSB) for a twelve-angle-of-attack.

Keywords: CFD, LES, Lift-to-drag ratio, LSB, NACA 0012 airfoil

Procedia PDF Downloads 386

Authors: Kaitlyn O'Mara, Michele Burford

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Estuaries and coastal bays can receive large quantities of sediment from surrounding catchments during flooding or high flow periods. Large river systems that feed freshwater into estuaries can flow through several catchments of varying geology. Human modification of catchments for agriculture, industry and urban use can contaminate soils with excess nutrients, trace metals and other pollutants. Land clearing, especially clearing of riparian vegetation, can accelerate erosion, mobilising, transporting and depositing soil particles into rivers, estuaries and coastal bays. In this study, a flood simulation experiment was used to study the flux of nutrients between soil particles and water during this erosion, transport and deposition process. Granite, sedimentary and basalt surface soils (as well as sub-soils of granite and sedimentary) were collected from eroding areas surrounding the Brisbane River, Australia. The <63 µm size fraction of each soil type was tumbled in freshwater for 3 days, to simulation flood erosion and transport, followed by stationary exposure to seawater for 4 weeks, to simulate deposition into estuaries. Filtered water samples were taken at multiple time points throughout the experiment and analysed for water nutrient concentrations. The highest rates of nutrient release occurred during the first hour of exposure to freshwater and seawater, indicating a chemical reaction with seawater that may act to release some nutrient particles that remain bound to the soil during turbulent freshwater transport. Although released at a slower rate than the first hour, all of the surface soil types showed continual ammonia, nitrite and nitrate release over the 4-week seawater exposure, suggesting that these soils may provide ongoing supply of these nutrients to estuarine waters after deposition. Basalt surface soil released the highest concentrations of phosphates and dissolved organic phosphorus. Basalt soils are found in much of the agricultural land surrounding the Brisbane River and contributed largely to the 2011 Brisbane River flood plume deposit in Moreton Bay, suggesting these soils may be a source of phosphate enrichment in the bay. The results of this study suggest that erosion of catchment soils during storm and flood events may be a source of nutrient supply in receiving waterways, both freshwater and marine, and that the amount of nutrient release following these events may be affected by the type of soil deposited. For example, flooding in different catchments of a river system over time may result in different algal and food web responses in receiving estuaries.

Keywords: flood, nitrogen, nutrient, phosphorus, sediment, soil

Procedia PDF Downloads 186

Authors: Zongyan Yang, Gagan K. Jena, Sankar B. Karanam, Noora M. A. Hokal

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Jumeirah First beach, a segment of coastline of length 1.5 km, is one of the popular public beaches in Dubai, UAE. The stability of the beach has been affected by several coastal developmental projects, including The World, Island 2 and La Mer. A comprehensive stabilization scheme comprising of two composite groynes (of lengths 90 m and 125m), modification to the northern breakwater of Jumeirah Fishing Harbour and beach re-nourishment was implemented by Dubai Municipality in 2012. However, the performance of the implemented stabilization scheme has been compromised by La Mer project (built in 2016), which modified the wave climate at the Jumeirah First beach. The objective of the coastal modelling studies is to establish design basis for further beach stabilization scheme(s). Comprehensive coastal modelling studies had been conducted to establish the nearshore wave climate, equilibrium beach orientations and stable beach plan forms. Based on the outcomes of the modeling studies, recommendation had been made to extend the composite groynes to stabilize the Jumeirah First beach. Wave transformation was performed following an interpolation approach with wave transformation matrixes derived from simulations of a possible range of wave conditions in the region. The Dubai coastal wave model is developed with MIKE21 SW. The offshore wave conditions were determined from PERGOS wave data at 4 offshore locations with consideration of the spatial variation. The lateral boundary conditions corresponding to the offshore conditions, at Dubai/Abu Dhabi and Dubai Sharjah borders, were derived with application of LitDrift 1D wave transformation module. The Dubai coastal wave model was calibrated with wave records at monitoring stations operated by Dubai Municipality. The wave transformation matrix approach was validated with nearshore wave measurement at a Dubai Municipality monitoring station in the vicinity of the Jumeirah First beach. One typical year wave time series was transformed to 7 locations in front of the beach to count for the variation of wave conditions which are affected by adjacent and offshore developments. Equilibrium beach orientations were estimated with application of LitDrift by finding the beach orientations with null annual littoral transport at the 7 selected locations. The littoral transport calculation results were compared with beach erosion/accretion quantities estimated from the beach monitoring program (twice a year including bathymetric and topographical surveys). An innovative integral method was developed to outline the stable beach plan forms from the estimated equilibrium beach orientations, with predetermined minimum beach width. The optimal lengths for the composite groyne extensions were recommended based on the stable beach plan forms.

Keywords: composite groyne, equilibrium beach orientation, stable beach plan form, wave transformation matrix

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Authors: Antonio Munar-Frau, Sascha Klismoch, Manfred Schmolz, Federico Hernandez-Alfaro, Jordi Caballe-Serrano

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Introduction: Biocompatibility of biomaterials has been proposed as one of the main criteria for treatment success. For guided bone regeneration (GBR), barrier membranes present a conflict given the number of origins and modifications of these materials. The biologic response to biomaterials is orchestrated by a series of events leading to the integration or rejection of the biomaterial, posing questions such as if a longer occlusive property may trigger an inflammatory reaction. Whole blood cultures are a solution to study the immune response to drugs or biomaterials during the first 24-48 hours. The aim of this study is to determine the early immune response of different origins and chemical modifications of barrier membranes. Materials & Methods: 5 different widely used barrier membranes were included in this study: Acellular dermal matrix (AlloDerm, LifeCell®), Porcine Peritoneum (BioGide, Geistlich Pharma®), Porcine Pericardium (Jason, Botiss Biomaterials GmbH®), Porcine Cross-linked collagen (Ossix Plus, Datum Dental®) and d-PTFE (Cytoplast TXT, Osteogenics Biomedical®). Blood samples were extracted from 3 different healthy donors and incubated with the different samples of barrier membranes for 24 hours. After the incubation time, serum samples were obtained and analyzed by means of biocompatibility assays taking into account 42 markers. Results: In an early stage of the inflammatory response, the Acellular dermal matrix, porcine peritoneum and porcine cross-linked collagen expressed similar patterns of cytokine expression with a great manifestation of ENA 78. Porcine pericardium and d-PTFE presented similar cytokine activation, especially for MMP-3 and MMP-9, although other cytokines were highlighted with lower expression. For the later immune response, Porcine peritoneum and acellular dermal matrix MCP-1 and IL-15 were evident. Porcine pericardium, porcine cross-linked collagen and d-PTFE presented a high expression of IL-16 and lower manifestation of other cytokines. Different behaviors depending on an earlier or later stage of the inflammation process were observed. Barrier membrane inflammatory expression does not only differ depending on the origin, variables such as treatment of the collagen and polymers may also have a great impact on the cytokine expression of the studied barrier membranes during inflammation. Conclusions: Surface treatment and modifications might affect the biocompatibility of the membranes, as different cytokine expressions were evidently depending on the origin of the biomaterial. This study is only a brushstroke regarding the biocompatibility of materials, as it is one of the pioneer studies for ex vivo barrier membranes assays. Studies regarding surface modification are needed in order to clarify mystifications of barrier membrane science.

Keywords: biomaterials, bone regeneration, biocompatibility, inflammation

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Authors: Aarthi Mariappan, Janani Selvaraj, P. B. Harathi, M. Prashanthi Devi

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Anthropogenic modification of the urban environment has largely increased in the recent years in order to sustain the growing human population. Intense industrial activity, permanent and high traffic on the roads, a developed subterranean infrastructure network, land use patterns are just some specific characteristics. Every day, the urban environment is polluted by more or less toxic emissions, organic or metals wastes discharged from specific activities such as industrial, commercial, municipal. When these eventually deposit into the soil, the physical and chemical properties of the surrounding soil is changed, transforming it into a human exposure indicator. Metals are non-degradable and occur cumulative in soil due to regular deposits are a result of permanent human activity. Due to this, metals are a contaminant factor for soil when persistent over a long period of time and a possible danger for inhabitant’s health on prolonged exposure. Metals accumulated in contaminated soil may be transferred to humans directly, by inhaling the dust raised from top soil, or by ingesting, or by dermal contact and indirectly, through plants and animals grown on contaminated soil and used for food. Some metals, like Cu, Mn, Zn, are beneficial for human’s health and represent a danger only if their concentration is above permissible levels, but other metals, like Pb, As, Cd, Hg, are toxic even at trace level causing gastrointestinal and lung cancers. In urban areas, metals can be emitted from a wide variety of sources like industrial, residential, commercial activities. Our study interrogates the spatial distribution of heavy metals in soil in relation to their permissible levels and their association with the health risk to the urban population in Coimbatore, India. Coimbatore region is a high cancer risk zone and case records of gastro intestinal and respiratory cancer patients were collected from hospitals and geocoded in ArcGIS10.1. The data of patients pertaining to the urban limits were retained and checked for their diseases history based on their diagnosis and treatment. A disease map of cancer was prepared to show the disease distribution. It has been observed that in our study area Cr, Pb, As, Fe and Mg exceeded their permissible levels in the soil. Using spatial overlay analysis a relationship between environmental exposure to these potentially toxic elements in soil and cancer distribution in Coimbatore district was established to show areas of cancer risk. Through this, our study throws light on the impact of prolonged exposure to soil contamination in soil in the urban zones, thereby exploring the possibility to detect cancer risk zones and to create awareness among the exposed groups on cancer risk.

Keywords: soil contamination, cancer risk, spatial analysis, India

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Authors: Eva Filová, Jana Daňková, Věra Sovková, Matej Daniel

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Titanium alloys are biocompatible metals that are widely used in clinical practice as load bearing implants. The chemical modification may influence cell adhesion, proliferation, and differentiation as well as stiffness of the material. The aim of the study was to evaluate the adhesion, growth and differentiation of pig mesenchymal stem cells on the novel beta titanium alloy Ti36Nb6Ta compared to standard medical titanium alloy Ti6Al4V. Discs of Ti36Nb6Ta and Ti6Al4V alloy were sterilized by ethanol, put in 48-well plates, and seeded by pig mesenchymal stem cells at the density of 60×103/cm2 and cultured in Minimum essential medium (Sigma) supplemented with 10% fetal bovine serum and penicillin/streptomycin. Cell viability was evaluated using MTS assay (CellTiter 96® AQueous One Solution Cell Proliferation Assay;Promega), cell proliferation using Quant-iT™ ds DNA Assay Kit (Life Technologies). Cells were stained immunohistochemically using monoclonal antibody beta-actin, and secondary antibody conjugated with AlexaFluor®488 and subsequently the spread area of cells was measured. Cell differentiation was evaluated by alkaline phosphatase assay using p-nitrophenyl phosphate (pNPP) as a substrate; the reaction was stopped by NaOH, and the absorbance was measured at 405 nm. Osteocalcin, specific bone marker was stained immunohistochemically and subsequently visualized using confocal microscopy; the fluorescence intensity was analyzed and quantified. Moreover, gene expression of osteogenic markers osteocalcin and type I collagen was evaluated by real-time reverse transcription-PCR (qRT-PCR). For statistical evaluation, One-way ANOVA followed by Student-Newman-Keuls Method was used. For qRT-PCR, the nonparametric Kruskal-Wallis Test and Dunn's Multiple Comparison Test were used. The absorbance in MTS assay was significantly higher on titanium alloy Ti6Al4V compared to beta titanium alloy Ti36Nb6Ta on days 7 and 14. Mesenchymal stem cells were well spread on both alloys, but no difference in spread area was found. No differences in alkaline phosphatase assay, fluorescence intensity of osteocalcin as well as the expression of type I collagen, and osteocalcin genes were observed. Higher expression of type I collagen compared to osteocalcin was observed for cells on both alloys. Both beta titanium alloy Ti36Nb6Ta and titanium alloy Ti6Al4V Ti36Nb6Ta supported mesenchymal stem cellsˈ adhesion, proliferation and osteogenic differentiation. Novel beta titanium alloys Ti36Nb6Ta is a promising material for bone implantation. The project was supported by the Czech Science Foundation: grant No. 16-14758S, the Grant Agency of the Charles University, grant No. 1246314 and by the Ministry of Education, Youth and Sports NPU I: LO1309.

Keywords: beta titanium, cell growth, mesenchymal stem cells, titanium alloy, implant

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