Search results for: molecular and supramolecular structure

Authors: Arvind Kumar Trivedi

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Our Earth is dynamic in nature and its structure behaves like a puzzle because the interior of the Earth is in both gaseous as well as molten (liquid) form and the crust i.e. the outermost surface is in solid form. This Earth was one landmass known as ‘Pangaea’ in the beginning. With time due to complex phenomena of tectonic movements, it was broken into various landmasses along with water bodies. This Pangaea was in direct contact with the atmosphere playing dominant role in creating various ecosystems on the Earth. Ecosystems mean: Eco (environment body) and systems (interdependent complex of all the organisms interacting with each other). This paper provides an in-depth discussion on tectonic movements as well as ecosystems & how these two affect each other and in the end, we will enlist various methods on how to preserve our ‘Mother Earth’.

Keywords: tectonic movements, ecosystems, plate tectonics, impact

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Authors: Hristina Šalipur, Jasmina Dostanić, Davor Lončarević, Matej Huš

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Photocatalytic water splitting/alcohol photoreforming has been used for the conversion of sunlight energy in the process of hydrogen production due to its sustainability, environmental safety, effectiveness and simplicity. Titanate nanotubes are frequently studied materials since they combine the properties of photo-active semiconductors with the properties of layered titanates, such as the ion-exchange ability. Platinum (Pt) doping into titanate structure has been considered an effective strategy in better separation efficiency of electron-hole pairs and lowering the overpotential for hydrogen production, which results in higher photocatalytic activity. In our work, Pt doped titanate catalysts were synthesized via simple alkaline hydrothermal treatment, incipient wetness impregnation method and temperature-programmed reduction. The structural, morphological and optical properties of the prepared catalysts were investigated using various characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 physisorption, and diffuse reflectance spectroscopy (DRS). The activities of the prepared Pt-doped titanate photocatalysts were tested for hydrogen production via photocatalytic water splitting/alcohol photoreforming process under simulated solar light irradiation. Characterization of synthesized Pt doped titanate catalysts showed crystalline anatase phase, preserved nanotubular structure and high specific surface area. The result showed enhancement of activity in photocatalytic water splitting/alcohol photoreforming in the following order 2-butanol>1-butanol>tert-butanol, with obtained maximal hydrogen production rate of 7.5, 5.3 and 2 mmol g-1 h-1, respectively. Different possible factors influencing the hole scavenging ability, such as hole scavenger redox potential and diffusivity, adsorption and desorption rate of the hole scavenger on the surface and stability of the alcohol radical species generated via hole scavenging, were investigated. The theoretical evaluation using density functional theory (DFT) further elucidated the reaction kinetics and detailed mechanism of photocatalytic water splitting/alcohol photoreforming.

Keywords: hydrogen production, platinum, semiconductor, water splitting, density functional theory

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Authors: Stephen Eyije Abechi, Casimir Emmanuel Gimba, Zaharaddeen Nasiru Garba, Sani Shamsudeen, David Ebuka Authur

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Corrosion inhibition of mild steel in acid medium using Acalypha chamaedrifolia leaves extract as potential green inhibitor was investigated. Gravimetric (weight loss) technique was used for the corrosion studies. Mild steel coupons of 2cm × 1cm × 0.27 cm dimensions were exposed for varying durations of between 24 to 120 hours, in 1M HCl medium containing a varying concentrations of the leaves extract (0.25g/L, - 1.25g/L). The results show that corrosion rates dropped from a value of 0.49 mgcm-2hr-1 for the uninhibited medium to a value of 0.15 mgcm-2hr-1 for the inhibited medium of 1M HCl in 0.25 g/l of the extract. Values of corrosion inhibition efficiencies of 70.38-85.11% were observed as the concentration of the inhibitor were increased from 0.25g/L, - 1.25g/L. Corrosion Inhibition was found to increase with increase in immersion time and temperature. The magnitude of the Ea indicates that the interaction between the metal surface and the inhibitor was chemisorptions. The Adsorption process fit into the Langmuir isotherm model with a correlation coefficient of 0.97. Evidence from molecular dynamics model shows that Methyl stearate (Line 5) and (3Z, 13Z)-2-methyloctadeca-3,13-dien-1-ol (line 11) were found to have the highest binding energy of -197.69 ± 3.12 and-194.56 ± 10.04 in kcal/mol respectively. The binding energy of these compounds indicates that they would be a very good corrosion inhibitor for mild steel and other Fe related materials.

Keywords: binding energy, corrosion, inhibitor, langmuir isotherm, mild steel

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Authors: Saad Mohamed Elsaid Abdelrahman

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The adsorption method is one of the best modern techniques used in removing pollutants, especially organic hydrocarbon compounds, from polluted water. Through this research, bentonite clay can be used to remove organic hydrocarbon compounds, such as heptane and octane, resulting from oil spills in seawater. Bentonite clay can be obtained from the Kholayaz area, located north of Jeddah, at a distance of 80 km. Chemical analysis shows that bentonite clay consists of a mixture of silica, alumina and oxides of some elements. Bentonite clay can be activated in order to raise its adsorption efficiency and to make it suitable for removing pollutants using an ionic organic solvent. It is necessary to study some of the factors that could be in the efficiency of bentonite clay in removing oily organic compounds, such as the time of contact of the clay with heptane and octane solutions, pH and temperature, in order to reach the highest adsorption capacity of bentonite clay. The temperature can be a few degrees Celsius higher. The adsorption capacity of the clay decreases when the temperature is raised more than 4°C to reach its lowest value at the temperature of 50°C. The results show that the friction time of 30 minutes and the pH of 6.8 is the best conditions to obtain the highest adsorption capacity of the clay, 467 mg in the case of heptane and 385 mg in the case of octane compound. Experiments conducted on bentonite clay were encouraging to select it to remove heavy molecular weight pollutants such as petroleum compounds under study.

Keywords: adsorbent, bentonite clay, oil spills, removal

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Authors: Michael Radwan Omary

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Context: This scientific innovation demonstrate organic catalysis engineered media effective desalination of surface and groundwater. The author has developed a technology called “Storm-Water Ions Filtration Treatment” (SWIFTTM) cold reactor modules designed to retrofit typical urban street storm drains or catch basins. SWIFT triggers biochemical redox reactions with water stream-embedded toxic total dissolved solids (TDS) and electrical conductivity (EC). SWIFTTM Catalysts media unlock the sub-molecular bond energy, break down toxic chemical bonds, and neutralize toxic molecules, bacteria and pathogens. Research Aim: This research aims to develop and design lower O&M cost, zero-brine discharge, energy input-free, chemical-free water desalination and disinfection systems. The objective is to provide an effective resilient and sustainable solution to urban storm-water and groundwater decontamination and disinfection. Methodology: We focused on the development of organic, non-chemical, no-plugs, no pumping, non-polymer and non-allergenic approaches for water and waste water desalination and disinfection. SWIFT modules operate by directing the water stream to flow freely through the electrically charged media cold reactor, generating weak interactions with a water-dissolved electrically conductive molecule, resulting in the neutralization of toxic molecules. The system is powered by harvesting sub-molecular bonds embedded in energy. Findings: The SWIFTTM Technology case studies at CSU-CI and CSU-Fresno Water Institute, demonstrated consistently high reduction of all 40 detected waste-water pollutants including pathogens to levels below a state of California Department of Water Resources “Drinking Water Maximum Contaminants Levels”. The technology has proved effective in reducing pollutants such as arsenic, beryllium, mercury, selenium, glyphosate, benzene, and E. coli bacteria. The technology has also been successfully applied to the decontamination of dissolved chemicals, water pathogens, organic compounds and radiological agents. Theoretical Importance: SWIFT technology development, design, engineering, and manufacturing, offer cutting-edge advancement in achieving clean-energy source bio-catalysis media solution, an energy input free water and waste water desalination and disinfection. A significant contribution to institutions and municipalities achieving sustainable, lower cost, zero-brine and zero CO2 discharges clean energy water desalination. Data Collection and Analysis Procedures: The researchers collected data on the performance of the SWIFTTM technology in reducing the levels of various pollutants in water. The data was analyzed by comparing the reduction achieved by the SWIFTTM technology to the Drinking Water Maximum Contaminants Levels set by the state of California. The researchers also conducted live oral presentations to showcase the applications of SWIFTTM technology in storm water capture and decontamination as well as providing clean drinking water during emergencies. Conclusion: The SWIFTTM Technology has demonstrated its capability to effectively reduce pollutants in water and waste water to levels below regulatory standards. The Technology offers a sustainable solution to groundwater and storm-water treatments. Further development and implementation of the SWIFTTM Technology have the potential to treat storm water to be reused as a new source of drinking water and an ambient source of clean and healthy local water for recharge of ground water.

Keywords: catalysis, bio electro interactions, water desalination, weak-interactions

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Authors: Rajendra Chetty

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Decolonial aesthetics departs and delinks from colonial ideas about ‘the arts’ and the modernist/colonial work of aesthetics. Education is trapped in the western epistemic and hermeneutical vocabulary, hence it is necessary to introduce new concepts and work the entanglement between co-existing concepts. This paper will discuss the contribution of Ronnie Govender, a South African writer, to build decolonial sensibilities and delink from the grand narrative of the colonial and apartheid literary landscape in Govender’s text, At the Edge and other Cato Manor Stories. Govender uses the world of art to make a decolonial statement. Decolonial artists have to work in the entanglement of power and engage with a border epistemology. Govender’s writings depart from an embodied consciousness of the colonial wound and moves toward healing. Border thinking and doing (artistic creativity) is precisely the decolonial methodology posited by Linda T. Smith, where theory comes in the form of storytelling. Govender’s stories engage with the wounds infringed by racism and patriarchy, two pillars of eurocentric knowing, sensing, and believing that sustain a structure of knowledge. This structure is embedded in characters, institutions, languages that regulate and mange the world of the excluded. Healing is the process of delinking, or regaining pride, dignity, and humanity, not through the psychoanalytic cure, but the popular healer. The legacies of the community of Cato Manor that was pushed out of their land are built in his stories. Decoloniality then is a concept that carries the experience of liberation struggles and recognizes the strenuous conditions of marginalized people together with their strength, wisdom, and endurance. Govender’s unique performative prose reconstructs and resurrects the lives of the people of Cato Manor, their vitality and humor, pain and humiliation: a vibrant and racially integrated community destroyed by the regime’s notorious racial laws. The paper notes that Govender’s objective with his plays and stories was to open windows to both the pain and joy of life; a mission that is not didactic but to shine a torch on both mankind’s waywardness as well as its inspiring and often moving achievements against huge odds.

Keywords: Govender, decoloniality, delinking, exclusion, racism, Cato Manor

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Authors: Natalia Koltovaya, Nadezhda Zhuchkina, Ksenia Lyubimova

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We study the biological effects induced by ionizing radiation in view of therapeutic exposure and the idea of space flights beyond Earth's magnetosphere. In particular, we examine the differences between base pair substitution induction by ionizing radiation in model haploid and diploid yeast Saccharomyces cerevisiae cells. Such mutations are difficult to study in higher eukaryotic systems. In our research, we have used a collection of six isogenic trp5-strains and 14 isogenic haploid and diploid cyc1-strains that are specific markers of all possible base-pair substitutions. These strains differ from each other only in single base substitutions within codon-50 of the trp5 gene or codon-22 of the cyc1 gene. Different mutation spectra for two different haploid genetic trp5- and cyc1-assays and different mutation spectra for the same genetic cyc1-system in cells with different ploidy — haploid and diploid — have been obtained. It was linear function for dose-dependence in haploid and exponential in diploid cells. We suggest that the differences between haploid yeast strains reflect the dependence on the sequence context, while the differences between haploid and diploid strains reflect the different molecular mechanisms of mutations.

Keywords: base pair substitutions, γ-rays, haploid and diploid cells, yeast Saccharomyces cerevisiae

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Authors: L. Richter, J. Lübkemann, P. Nyhuis

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In order to remain competitive in what is a turbulent environment; businesses must be able to react rapidly to change. The past response to volatile market conditions was to introduce an element of flexibility to production. Nowadays, what is often required is a redesign of factory structures in order to cope with the state of constant flux. The Institute of Production Systems and Logistics is currently developing a descriptive and causal model for the redesign of plant structures as part of an ongoing research project. This article presents the first research findings attained in devising this model.

Keywords: change driven factory redesign, factory planning, plant structure, flexibility

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Authors: Intan Waheedah Othman, Maslinawati Mohamad, Azizah Abdullah

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Few discussions were made on cooperative governance reforms despite the fact that cooperative movements operate and compete in an identical business environment as the private as well as the public corporations. Due to the scarcity of research examining the issue of governance among cooperatives, this paper is motivated to examine the extent of governance compliance and disclosure among cooperatives, hence the relationship between cooperative governance and its firm performance. Results from the study provide empirical evidence that disclosure on ownership structure and exercise of control rights was found to have significant negative relationship with cooperative firm performance.

Keywords: cooperative, governance, firm performance, Malaysia

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Authors: Joshua N. Edokpayi, John O. Odiyo, Titus A. M. Msagati, Elizabeth O. Popoola

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Polycyclic aromatic hydrocarbons (PAHs) are very toxic and persistent environmental contaminants. This study was undertaken to assess the concentrations and possible sources of 16 PAHs classified by the United State Environmental Protection Agency as priority pollutants in Mvudi and Nzhelele Rivers and sediments. Effluents from Thohoyandou wastewater treatment plant and Siloam waste stabilization ponds were also investigated. Diagnostic ratios were used to evaluate the possible sources of PAHs. PAHs in the water samples were extracted using 1:1 dichloromethane and n-hexane mixtures, while those in the sediment samples were extracted with 1:1 acetone and dichloromethane using ultrasonication method. The extracts were purified using SPE technique and reconstituted in n-hexane before analyses with GC-TOF-MS. The results obtained indicate the prevalence of high molecular weight PAHs in all the samples. PAHs concentrations in water and sediment samples from all the sampling sites were in the range of 13.174-26.382 mg/L and 27.10-55.93 mg/kg, respectively. Combustion of biomass was identified as the major possible source of PAHs. Effluents from wastewater treatment facilities were also considered as major anthropogenic contributions to the levels of PAHs determined in both river waters and sediments. Mvudi and Nzhelele Rivers show moderate to high contamination level of PAHs.

Keywords: polycyclic aromatic hydrocarbon, rivers, sediments, wastewater effluents

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Authors: Joseph E. Estevez, Mahdi Ghazizadeh, James G. Ryan, Ajit D. Kelkar

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Radiation shielding is an obstacle in long duration space exploration. Boron Nitride Nanotubes (BNNTs) have attracted attention as an additive to radiation shielding material due to B10’s large neutron capture cross section. The B10 has an effective neutron capture cross section suitable for low energy neutrons ranging from 10-5 to 104 eV and hydrogen is effective at slowing down high energy neutrons. Hydrogenated BNNTs are potentially an ideal nanofiller for radiation shielding composites. We use Molecular Dynamics (MD) Simulation via Material Studios Accelrys 6.0 to model the Young’s Modulus of Hydrogenated BNNTs. An extrapolation technique was employed to determine the Young’s Modulus due to the deformation of the nanostructure at its theoretical density. A linear regression was used to extrapolate the data to the theoretical density of 2.62g/cm3. Simulation data shows that the hydrogenated BNNTs will experience a 11% decrease in the Young’s Modulus for (6,6) BNNTs and 8.5% decrease for (8,8) BNNTs compared to non-hydrogenated BNNT’s. Hydrogenated BNNTs are a viable option as a nanofiller for radiation shielding nanocomposite materials for long range and long duration space exploration.

Keywords: boron nitride nanotube, radiation shielding, young modulus, atomistic modeling

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Authors: Kave Moloudi, Heidi Abrahamse, Blassan P. George

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Radiotherapy (RT) and photodynamic therapy (PDT) are both forms of cancer treatment that aim to kill cancer cells while minimizing damage to healthy tissue. The similarity between RT and PDT lies in their mechanism of action. Both treatments use energy to damage cancer cells. RT uses high-energy radiation to damage the DNA of cancer cells, while PDT uses light energy to activate a photosensitizing agent, which produces reactive oxygen species (ROS) that damage the cancer cells. Both treatments require careful planning and monitoring to ensure the correct dose is delivered to the tumor while minimizing damage to surrounding healthy tissue. They are also often used in combination with other treatments, such as surgery or chemotherapy, to improve overall outcomes. However, there are also significant differences between RT and PDT. For example, RT is a non-invasive treatment that can be delivered externally or internally, while PDT requires the injection of a photosensitizing agent and the use of a specialized light source to activate it. Additionally, the side effects and risks associated with each treatment can vary. In this review, we focus on generalizing the 6Rs of radiobiology in PDT, which can open a window for the clinical application of Radio-photodynamic therapy with minimum side effects. Furthermore, this review can open new insight to work on and design new radio-photosensitizer agents in Radio-photodynamic therapy.

Keywords: radiobiology, photodynamic therapy, radiotherapy, 6Rs in radiobiology, ROS, DNA damages, cellular and molecular mechanism, clinical application.

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Authors: Sultan Ben Jaber

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Optical properties of molecules exhibit dramatic changes when adsorbed close to nano-structure metallic surfaces such as gold and silver nanomaterial. This phenomena opened a wide range of research to improve conventional spectroscopies efficiency. A well-known technique that has an intensive focus of study is surface-enhanced Raman spectroscopy (SERS), as since the first observation of SERS phenomena, researchers have published a great number of articles about the potential mechanisms behind this effect as well as developing materials to maximize the enhancement. Infrared and Raman spectroscopy are complementary techniques; thus, surface-enhanced infrared absorption (SEIRA) also shows a noticeable enhancement of molecules in the mid-IR excitation on nonmetallic structure substrates. In the SEIRA, vibrational modes that gave change in dipole moments perpendicular to the nano-metallic substrate enhanced 200 times greater than the free molecule’s modes. SEIRA spectroscopy is promising for the characterization and identification of adsorbed molecules on metallic surfaces, especially at trace levels. IR reflection-absorption spectroscopy (IRAS) is a well-known technique for measuring IR spectra of adsorbed molecules on metallic surfaces. However, SEIRA spectroscopy sensitivity is up to 50 times higher than IRAS. SEIRA enhancement has been observed for a wide range of molecules adsorbed on metallic substrates such as Au, Ag, Pd, Pt, Al, and Ni, but Au and Ag substrates exhibited the highest enhancement among the other mentioned substrates. In this work, trace levels of 3,4-methylenedioxymethamphetamine (MDMA) have been detected using gold nanoparticles (AuNPs) substrates with surface-enhanced infrared absorption (SEIRA). AuNPs were first prepared and washed, then mixed with different concentrations of MDMA samples. The process of fabricating the substrate prior SEIRA measurements included mixing of AuNPs and MDMA samples followed by vigorous stirring. The stirring step is particularly crucial, as stirring allows molecules to be robustly adsorbed on AuNPs. Thus, remarkable SEIRA was observed for MDMA samples even at trace levels, showing the rigidity of our approach to preparing SEIRA substrates.

Keywords: surface-enhanced infrared absorption (SEIRA), gold nanoparticles (AuNPs), amphetamines, methylene dioxy- methamphetamine (MDMA), enhancement factor

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Authors: Tim Bolle, Franziska Kreimendahl, Thomas Gries, Stefan Jockenhoevel

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The therapeutic treatment of extensive, deep wounds is limited. Autologous split-skin grafts are used as a so-called ‘gold standard’. Most common deficits are the defects at the donor site, the risk of scarring as well as the limited availability and quality of the autologous grafts. The aim of this project is a tissue engineered dermal-epidermal skin replacement to overcome the limitations of the gold standard. A key requirement for the development of such a three-dimensional implant is the formation of a functional capillary-like network inside the implant to ensure a sufficient nutrient and gas supply. Tailored three-dimensional warp knitted spacer fabrics are used to reinforce the mechanically week fibrin gel-based scaffold and further to create a directed in vitro pre-vascularization along the parallel-oriented pile yarns within a co-culture. In this study various three-dimensional warp knitted spacer fabrics were developed in a factorial design to analyze the influence of the machine parameters such as the stitch density and the pattern of the fabric on the scaffold performance and further to determine suitable parameters for a successful fibrin gel-incorporation and a physiological performance of the scaffold. The fabrics were manufactured on a Karl Mayer double-bar raschel machine DR 16 EEC/EAC. A fine machine gauge of E30 was used to ensure a high pile yarn density for sufficient nutrient, gas and waste exchange. In order to ensure a high mechanical stability of the graft, the fabrics were made of biocompatible PVDF yarns. Key parameters such as the pore size, porosity and stress/strain behavior were investigated under standardized, controlled climate conditions. The influence of the input parameters on the mechanical and morphological properties as well as the ability of fibrin gel incorporation into the spacer fabric was analyzed. Subsequently, the pile yarns of the spacer fabrics were colonized with Human Umbilical Vein Endothelial Cells (HUVEC) to analyze the ability of the fabric to further function as a guiding structure for a directed vascularization. The cells were stained with DAPI and investigated using fluorescence microscopy. The analysis revealed that the stitch density and the binding pattern have a strong influence on both the mechanical and morphological properties of the fabric. As expected, the incorporation of the fibrin gel was significantly improved with higher pore sizes and porosities, whereas the mechanical strength decreases. Furthermore, the colonization trials revealed a high cell distribution and density on the pile yarns of the spacer fabrics. For a tailored reinforcing structure, the minimum porosity and pore size needs to be evaluated which still ensures a complete incorporation of the reinforcing structure into the fibrin gel matrix. That will enable a mechanically stable dermal graft with a dense vascular network for a sufficient nutrient and oxygen supply of the cells. The results are promising for subsequent research in the field of reinforcing mechanically weak biological scaffolds and develop functional three-dimensional scaffolds with an oriented pre-vascularization.

Keywords: fibrin-gel, skin replacement, spacer fabric, pre-vascularization

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Authors: M. Marchewka

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The article is devoted to the possible optical transitions in double quantum wells system based on HgTe/HgCd(Mn)Te heterostructures. Such structures can find applications as detectors and sources of radiation in the terahertz range. The Double Quantum Wells (DQW) systems consist of two QWs separated by the transparent for electrons barrier. Such systems look promising from the point of view of the additional degrees of freedom. In the case of the topological insulator in about 6.4nm wide HgTe QW or strained 3D HgTe films at the interfaces, the topologically protected surface states appear at the interfaces/surfaces. Electrons in those edge states move along the interfaces/surfaces without backscattering due to time-reversal symmetry. Combination of the topological properties, which was already verified by the experimental way, together with the very well know properties of the DQWs, can be very interesting from the applications point of view, especially in the THz area. It is important that at the present stage, the technology makes it possible to create high-quality structures of this type, and intensive experimental and theoretical studies of their properties are already underway. The idea presented in this paper is based on the eight-band KP model, including the additional terms related to the structural inversion asymmetry, interfaces inversion asymmetry, the influence of the magnetically content, and the uniaxial strain describe the full pictures of the possible real structure. All of this term, together with the external electric field, can be sources of breaking symmetry in investigated materials. Using the 8 band KP model, we investigated the electronic shape structure with and without magnetic field from the application point of view as a THz detector in a small magnetic field (below 2T). We believe that such structures are the way to get the tunable topological insulators and the multilayer topological insulator. Using the one-dimensional electrons at the topologically protected interface states as fast and collision-free signal carriers as charge and signal carriers, the detection of the optical signal should be fast, which is very important in the high-resolution detection of signals in the THz range. The proposed engineering of the investigated structures is now one of the important steps on the way to get the proper structures with predicted properties.

Keywords: topological insulator, THz spectroscopy, KP model, II-VI compounds

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Authors: Nour El Houda Bensiradj, Nafila Zouaghi, Taha Bensiradj

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The pollution of water resources is characterized by the presence of microorganisms, chemicals, or industrial waste. Generally, this waste generates effluents containing large quantities of heavy metals, making the water unsuitable for consumption and causing the death of aquatic life and associated biodiversity. Currently, it is very important to assess the impact of heavy metals in water pollution as well as the processes for treating and reducing them. Among the methods of water treatment and disinfection, we mention the complexation of metal ions using ligands which serve to precipitate and subsequently eliminate these ions. In this context, we are interested in the study of complexes containing heavy metals such as zinc, nickel, and cadmium, which are present in several industrial discharges and are discharged into water sources. We will use the ligands of triethanolamine (TEA) and nitrilotriacetic acid (NTA). The theoretical study is based on molecular modeling, using the density functional theory (DFT) implemented in the Gaussian 09 program. The geometric and energetic properties of the above complexes will be calculated. Spectral properties such as infrared, as well as reactivity descriptors, and thermodynamic properties such as enthalpy and free enthalpy will also be determined.

Keywords: heavy metals, NTA, TEA, DFT, IR, reactivity descriptors

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Authors: Randa M. Mostafa, Y. Moustafa

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During our daily life, we are continuously exposed to the extremely low frequency electromagnetic fields (ELF-EMFs) generated by electric appliances. The possible relation between exposure to (ELF-MFs) and adverse health effects has attracted and passed through long debate sessions. Extremely low frequency is a term used to describe radiation frequencies below 300 Hertz (Hz).It is very important for public health because of the widespread use of electrical power at 50-60 Hz in most countries. This study set out to investigate the impact of chronic exposure of male rats to 50- Hz, 1 mTesla (ELF-EMF) of over periods of 1, 2, and 4 weeks on concentration of serum FSH, LH, and testosterone hormones. 60 male albino rats were divided into 6 groups and were continuously exposed to 50-Hz, 1 m Tesla (ELF-EMF) generated by magnetic field chamber for periods of 1, 2, and 4 weeks. For each experimental point, sham treated group was used as a control. Assay of serum testosterone LH, and FSHwere performed. Serum testosterone showed no significant changes. FSH showed significant increase than sham exposed group after 1 week of field exposure. LH showed significant increase than sham exposed group only after 4 weeks of field exposure. A future detailed molecular studies must be carried out to figure out and may be able to explain the possible interactions between ELF-EMF and hypothalamic-pituitary gonadal axis.

Keywords: extremely low frequency electromagnetic fields, testosterone, follicular stimulating hormone, LH

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Authors: M. S. Abd El-Sadek, M. A. Omar, Gharib M. Taha

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In recent years, photocatalytic degradation of various kinds of organic and inorganic pollutants using semiconductor powders as photocatalysts has been extensively studied. Owing to its relatively high photocatalytic activity, biological and chemical stability, low cost, nonpoisonous and long stable life, Tin oxide materials have been widely used as catalysts in chemical reactions, including synthesis of vinyl ketone, oxidation of methanol and so on. Tin oxide (SnO₂), with a rutile-type crystalline structure, is an n-type wide band gap (3.6 eV) semiconductor that presents a proper combination of chemical, electronic and optical properties that make it advantageous in several applications. In the present work, SnO₂ nanoparticles were synthesized at room temperature by the sol-gel process and thermohydrolysis of SnCl₂ in isopropanol by controlling the crystallite size through calculations. The synthesized nanoparticles were identified by using XRD analysis, TEM, FT-IR, and Uv-Visible spectroscopic techniques. The crystalline structure and grain size of the synthesized samples were analyzed by X-Ray diffraction analysis (XRD) and the XRD patterns confirmed the presence of tetragonal phase SnO₂. In this study, Methylene blue degradation was tested by using SnO₂ nanoparticles (at different calculations temperatures) as a photocatalyst under sunlight as a source of irradiation. The results showed that the highest percentage of degradation of Methylene blue dye was obtained by using SnO₂ photocatalyst at calculations temperature 800 ᵒC. The operational parameters were investigated to be optimized to the best conditions which result in complete removal of organic pollutants from aqueous solution. It was found that the degradation of dyes depends on several parameters such as irradiation time, initial dye concentration, the dose of the catalyst and the presence of metals such as silver as a dopant and its concentration. Percent degradation was increased with irradiation time. The degradation efficiency decreased as the initial concentration of the dye increased. The degradation efficiency increased as the dose of the catalyst increased to a certain level and by further increasing the SnO₂ photocatalyst dose, the degradation efficiency is decreased. The best degradation efficiency on which obtained from pure SnO₂ compared with SnO₂ which doped by different percentage of Ag.

Keywords: SnO₂ nanoparticles, a sol-gel method, photocatalytic applications, methylene blue, degradation efficiency

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Authors: Kiyoumars Roushangar, Shabnam Mirheidarian

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This study proposes metamodel approaches as a new intelligent technique for the explicit formulation of friction factors of water conveyance structures. For this purpose, experimental data of a movable bed flume with dune bed form were used. Analyzing the result clears the high capability of metamodel approaches (MNE= 0.05, R= 0.92) as a powerful tool for optimizing and explicit simulation of Manning's roughness coefficients of water conveyance structures compared to other nonlinear approaches.

Keywords: intelligent techniques, explicit simulation, roughness coefficient, water conveyance structure

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Authors: Piyawan Srisuruk, Janya Boonmeeprasert, Romwarin Gamlunglert, Benjamaporn Choikhruea, Ornjira Jaraepram, Jarin Boonsuchat, Sakdadech Singkibud, Kusalaporn Chaiudomsom, Chanatiporn Chonprai, Pornchanaka Tana, Suchat Paholpak

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Objective: To develop an Intensive and comprehensive program (ICP) for the Inclusive Class Teacher (ICPICT) to teach elementary students (ES) with ASD in order to enhance the students’ academic and social skills (ASS) and to study the effect of the teaching program. Methods: The purposive sample included 15 Khon Kaen inclusive class teachers and their 15 elementary students. All the students were diagnosed by a child and adolescent psychiatrist to have DSM-5 level 1 ASD. The study tools included 1) an ICP to teach teachers about ASD, a teaching method to enhance academic and social skills for ES with ASD, and an assessment tool to assess the teacher’s knowledge before and after the ICP. 2) an ICPICT to teach ES with ASD to enhance their ASS. The project taught 10 sessions, 3 hours each. The ICPICT had its teaching structure. Teaching media included: pictures, storytelling, songs, and plays. The authors taught and demonstrated to the participant teachers how to teach with the ICPICT until the participants could display the correct teaching method. Then the teachers taught ICPICT at school by themselves 3) an assessment tool to assess the students’ ASS before and after the completion of the study. The ICP to teach the teachers, the ICPICT, and the relevant assessment tools were developed by the authors and were adjusted until consensus agreed as appropriate for researching by 3 curriculum of teaching children with ASD experts. The data were analyzed by descriptive and analytic statistics via SPSS version 26. Results: After the briefing, the teachers increased the mean score, though not with statistical significance, of knowledge of ASD and how to teach ES with ASD on ASS (p = 0.13). Teaching ES with ASD with the ICPICT could increase the mean scores of the students’ skills in learning and expressing social emotions, relationships with a friend, transitioning, and skills in academic function 3.33, 2.27, 2.94, and 3.00 scores (full scores were 18, 12, 15 and 12, Paired T-Test p = 0.007, 0.013, 0.028 and 0.003 respectively). Conclusion: The program to teach academic and social skills simultaneously in an intensive and comprehensive structure could enhance both the academic and social skills of elementary students with ASD. Keywords: Elementary students, autism spectrum, academic skill, social skills, intensive program, comprehensive program, integration.

Keywords: academica and social skills, students with autism, intensive and comprehensive, teaching program

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Authors: Tiisetso Mpai, Sanjay K. Jaiswal, Felix D. Dakora

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The South African Cape fynbos biome is a global biodiversity hotspot. This biome contains a diversity of endemic shrub legumes, including Polhillia, Wiborgia, and Wiborgiella species, which are important for ecotourism as well as for improving soil fertility status. This is due to their proven N₂-fixing abilities when in association with compatible soil bacteria. In fact, Polhillia, Wiborgia, and Wiborgiella species have been reported to derive over 61% of their needed nitrogen through biological nitrogen fixation and to exhibit acid and alkaline phosphatase activity in their rhizospheres. Thus, their interactions with soil microbes may explain their survival mechanisms under the continued summer droughts and acidic, nutrient-poor soils in this region. However, information regarding their rhizosphere microbiome is still unavailable, yet it is important for Fynbos biodiversity management. Therefore, the aim of this study was to assess the microbial community structures associated with rhizosphere soils of Polhillia pallens, Polhillia brevicalyx, Wiborgia obcordata, Wiborgia sericea, and Wiborgiella sessilifolia growing at different locations of the South African Cape fynbos, during the wet and dry seasons. The hypothesis is that the microbial communities in these legume rhizospheres are the same type and are not affected by the growing season due to the restricted habitat of these wild fynbos legumes. To obtain the results, DNA was extracted from 0.5 g of each rhizosphere soil using PowerSoil™ DNA Isolation Kit, and sequences were obtained using the 16S rDNA Miseq Illumina technology. The results showed that in both seasons, bacteria were the most abundant microbial taxa in the rhizosphere soils of all five legume species, with Actinobacteria showing the highest number of sequences (about 30%). However, over 19.91% of the inhabitants in all five legume rhizospheres were unclassified. In terms of genera, Mycobacterium and Conexibacter were common in rhizosphere soils of all legumes in both seasons except for W. obcordata soils sampled during the dry season, which had Dehalogenimonas as the major inhabitant (6.08%). In conclusion, plant species and season were found to be the main drivers of microbial community structure in Cape fynbos, with the wet season being more dominant in shaping microbial diversity relative to the dry season. Wiborgia obcordata had a greater influence on microbial community structure than the other four legume species.

Keywords: 16S rDNA, Cape fynbos, endemic legumes, microbiome, rhizosphere

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Authors: Ashish Kumar Pathak, Ritika Sharma, Vishal Nath, Sudhir Pratap Singh, Rakesh Tuli

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Litchi is a sub-tropical fruit crop with genotypes bearing delicious juicy fruits with variable seed size (bold to rudimentary size). Small seed size is a desirable trait in litchi, as it increases consumer acceptance and fruit processing. The biochemical activities in mid- stage ovules (e.g. 16, 20, 24 and 28 days after anthesis) determine the fate of seed and fruit development in litchi. Comprehensive ovule-specific transcriptome analysis was performed in two litchi genotypes with contrasting seed size to gain molecular insight on determinants of seed fates in litchi fruits. The transcriptomic data was de-novo assembled in 1,39,608 trinity transcripts, out of which 6,325 trinity transcripts were differentially expressed between the two contrasting genotypes. Differential transcriptional pattern was found among ovule development stages in contrasting litchi genotypes. The putative genes for salicylic acid, jasmonic acid and brassinosteroid pathway were down-regulated in ovules of small-seeded litchi. Embryogenesis, cell expansion, seed size and stress related trinity transcripts exhibited altered expression in small-seeded genotype. The putative regulators of seed maturation and seed storage were down-regulated in small-seed genotype.

Keywords: Litchi, seed, transcriptome, defence

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Authors: Khaled I. Nawafleh

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In this work, we apply the method of Hamilton-Jacobi to obtain solutions of Hamiltonian systems in classical mechanics with two certain structures: the first structure plays a central role in the theory of time-dependent Hamiltonians, whilst the second is used to treat classical Hamiltonians, including dissipation terms. It is proved that the generalization of problems from the calculus of variation methods in the nonstationary case can be obtained naturally in Hamilton-Jacobi formalism. Then, another expression of geometry of the Hamilton Jacobi equation is retrieved for Hamiltonians with time-dependent and frictional terms. Both approaches shall be applied to many physical examples.

Keywords: Hamilton-Jacobi, time dependent lagrangians, dissipative systems, variational principle

Procedia PDF Downloads 169

Authors: Kesavan Markkandan, Ha Young Park, Seung-Il Yoo, Sin-Gi Park, Junhyung Park

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For genetic identification of crop cultivars, insertions/deletions (InDel) markers have been preferred currently because they are easy to use, PCR based, co-dominant and relatively abundant. However, new InDels need to be developed for genetic studies of new varieties due to the difference of allele frequencies in InDels among the population groups. These new varieties are evolved with low levels of genetic diversity in specific genome loci with high recombination rate. In this study, we described soybean barcode system approach based on InDel makers, each of which is specific to a variation block (VB), where the genomes split by all assumed recombination sites. Firstly, VBs in crop cultivars were mined for transferability to VB-specific InDel markers. Secondly, putative InDels in the VB regions were identified for the development of barcode system by analyzing particular cultivar’s whole genome data. Thirdly, common VB-specific InDels from all cultivars were selected by gel electrophoresis, which were converted as 2D barcode types according to comparing amplicon polymorphisms in the five cultivars to the reference cultivar. Finally, the polymorphism of the selected markers was assessed with other cultivars, and the barcode system that allows a clear distinction among those cultivars is described. The same approach can be applicable for other commercial crops. Hence, VB-based genetic identification not only minimize the molecular markers but also useful for assessing cultivars and for marker-assisted breeding in other crop species.

Keywords: variation block, polymorphism, InDel marker, genetic identification

Procedia PDF Downloads 371

Authors: M. Benhamida, Kh. Bouamama, P. Djemia

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We investigate by first-principles pseudo-potential calculations the composition dependence of lattice parameter, hardness and elastic properties of ternary disordered solid solutions Ti(1-x)Ta(x)N (1>=x>=0) with B1-rocksalt structure. Calculations use the coherent potential approximation with the exact muffin-tin orbitals (EMTO) and hardness formula for multicomponent covalent solid solution proposed. Bulk modulus B shows a nearly linear behaviour whereas not C44 and C’=(C11-C12)/2 that are not monotonous. Influences of vacancies on hardness of off-stoichiometric transition-metal nitrides TiN(1−x) and TaN(1−x) are also considered.

Keywords: transition metal nitride materials, elastic constants, hardness, EMTO

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Authors: A.R. Eskandari, M.R. Eskandari

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A 2D complete identification algorithm for dielectric and multiple objects immersed in air is presented. The employed technique consists of initially retrieving the shape and position of the scattering object using a linear sampling method and then determining the electric permittivity and conductivity of the scatterer using adjoint sensitivity analysis. This inversion algorithm results in high computational speed and efficiency, and it can be generalized for any scatterer structure. Also, this method is robust with respect to noise. The numerical results clearly show that this hybrid approach provides accurate reconstructions of various objects.

Keywords: inverse scattering, microwave imaging, two-dimensional objects, Linear Sampling Method (LSM)

Procedia PDF Downloads 380

Authors: Chen-Fu Wang, Lin-Ya Kung

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For traditional painting materials, the artisan used to combine the pigments with different binders to create colors. As time goes by, the materials used for painting evolved from natural to chemical materials. The vast variety of ingredients used in chemical materials has complicated restoration work; it makes conservation work more difficult. Conservation work also becomes harder when the materials cannot be easily identified; therefore, it is essential that we take a more scientific approach to assist in conservation work. Paintings materials are high molecular weight polymer, and their analysis is very complicated as well other contamination such as smoke and dirt can also interfere with the analysis of the material. The current methods of composition analysis of painting materials include Fourier transform infrared spectroscopy (FT-IR), mass spectrometer, Raman spectroscopy, X-ray diffraction spectroscopy (XRD), each of which has its own limitation. In this study, FT-IR was used to analyze the components of the paint coating. We have taken the most commonly seen materials as samples and deteriorated it. The aged information was then used for the database to exam the temple painting materials. By observing the FT-IR changes over time, we can tell all of the painting materials will be deteriorated by the UV light, but only the speed of its degradation had some difference. From the deterioration experiment, the acrylic resin resists better than the others. After collecting the painting materials aging information on FT-IR, we performed some test on the paintings on the temples. It was found that most of the artisan used tune-oil for painting materials, and some other paintings used chemical materials. This method is now working successfully on identifying the painting materials. However, the method is destructive and high cost. In the future, we will work on the how to know the painting materials more efficiently.

Keywords: temple painting, painting material, conservation, FT-IR

Procedia PDF Downloads 183

Authors: Yanin Hosakun, Sujitra Wongkasemjit, Thanyalak Chaisuwan

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Carbon dioxide removal from natural gas is an important process because the existence of carbon dioxide in natural gas contributes to pipeline corrosion, reduces the heating value, and takes up volume in the pipeline. In this study, bacterial cellulose was chosen for the CO2/CH4 gas separation membrane due to its unique structure and prominent properties. Additionally, it can simply be obtained by culturing the bacteria so called “Acetobacter xylinum” through fermentation of coconut juice. Bacterial cellulose membranes with and without silver ions were prepared and studied for the separation performance of CO2 and CH4.

Keywords: bacterial cellulose, CO2, CH4 separation, membrane, nata de coco

Procedia PDF Downloads 247

Authors: S. M. Anisuzzaman, Sariah Abang, Awang Bono, D. Krishnaiah, N. M. Ismail, G. B. Sandrison

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Wax and asphaltene are high molecular weighted compounds that contribute to the stability of crude oil at a dispersed state. Transportation of crude oil along pipelines from the oil rig to the refineries causes fluctuation of temperature which will lead to the coagulation of wax and flocculation of asphaltenes. This paper focuses on the prevention of wax and asphaltene precipitate deposition on the inner surface of the pipelines by using a wax inhibitor and an asphaltene dispersant. The novelty of this prevention method is the combination of three substances; a wax inhibitor dissolved in a wax inhibitor solvent and an asphaltene solvent, namely, ethylene-vinyl acetate (EVA) copolymer dissolved in methylcyclohexane (MCH) and toluene (TOL) to inhibit the precipitation and deposition of wax and asphaltene. The objective of this paper was to optimize the percentage composition of each component in this inhibitor which can maximize the viscosity reduction of crude oil. The optimization was divided into two stages which are the laboratory experimental stage in which the viscosity of crude oil samples containing inhibitor of different component compositions is tested at decreasing temperatures and the data optimization stage using response surface methodology (RSM) to design an optimizing model. The results of experiment proved that the combination of 50% EVA + 25% MCH + 25% TOL gave a maximum viscosity reduction of 67% while the RSM model proved that the combination of 57% EVA + 20.5% MCH + 22.5% TOL gave a maximum viscosity reduction of up to 61%.

Keywords: asphaltene, ethylene-vinyl acetate, methylcyclohexane, toluene, wax

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Authors: Abdullah Mohammad, Abdullah Alshemali, Esmaeil Alsaleh

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The chemical composition of desalinated water is modified to make it more acceptable to the end-user. Sometimes, this modification is approached by mixing with brackish water that is known to contain a variety of minerals. Expectedly, besides minerals, brackish water indigenous bacterial communities access the final mixture hence reaching the end consumer. The current project examined the safety of using brackish water as an ingredient in potable water. Pseudomonas aeruginosa strains were detected in potable and brackish water samples collected from storage facilities in residential areas as well as from main water distribution and storage tanks. The application of molecular and biochemical fingerprinting methods, including phylogeny, RFLP (restriction fragment length polymorphism), MLST (multilocus sequence typing) and substrate specificity testing, suggested that the potable water P. aeruginosa strains were most probably originated from brackish water. Additionally, all the sixty-four isolates showed multi-drug resistance (MDR) phenotype and harboured the three genes responsible for biofilm formation. These virulence factors represent serious health hazards compelling the scientific community to revise the WHO (World Health Organization) and USEP (US Environmental Protection Agency) A potable water quality guidelines, particularly those related to the types of bacterial genera that evade the current water quality guidelines.

Keywords: potable water, brackish water, pseudomonas aeroginosa, multidrug resistance

Procedia PDF Downloads 113