Search results for: bone tissue density of jaws

Authors: Shangerganesh Lingeshwaran

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In this presentation, we have performed numerical simulations for a reaction-diffusion equation with various nonlinear density-dependent diffusion operators and proliferation functions. The mathematical model represented by parabolic partial differential equation is considered to study the invasion of gliomas (the most common type of brain tumors) and to describe the growth of cancer cells and response to their treatment. The unknown quantity of the given reaction-diffusion equation is the density of cancer cells and the mathematical model based on the proliferation and migration of glioma cells. A standard Galerkin finite element method is used to perform the numerical simulations of the given model. Finally, important observations on the each of nonlinear diffusion functions and proliferation functions are presented with the help of computational results.

Keywords: glioma invasion, nonlinear diffusion, reaction-diffusion, finite eleament method

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Authors: Nurul Izzah Ibrahim, Isa Naina Mohamed, Norazlina Mohamed, Ahmad Nazrun Shuid

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Osteoporosis disease delays fracture healing. Statins have shown potential for osteoporosis and to promote fracture healing. The effects of statin can be further potentiated by combining it with a carrier known as poly-(DL-lactide), which would provide persistent release of statin to the fracture site. This study was designed to investigate the effects of direct injection of poly-(DL-lactide)-incorporated lovastatin on fracture healing of postmenopausal osteoporosis rat model. Twenty-four Sprague-Dawley female rats were divided into 3 groups: sham-operated (SO), ovariectomized-control rats (OVxC) and poly-(DL-lactide)-incorporated lovastatin (OVx+Lov) groups. The OVx+Lov group was given a single injection of 750 µg/kg lovastatin particles incorporated with poly-(DL-lactide). After 4 weeks, the fractured tibiae were dissected out for biomechanical assessments of the callus. The OVx+Lov group showed significantly better callus strength than the OVxC group (p<0.05). In conclusion, a single injection of lovastatin-incorporated poly-(DL-lactide) was able to promote better fracture healing of osteoporotic bone.

Keywords: statins, fracture healing, osteoporosis, poly-(DL-lactide)

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Authors: S. Ghalem, M. Mesmoudi, I. Daoudand, H. Allali

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The nitrogen-containing bisphosphonates (N-BPs) are well established as the treatments of choice for disorders of excessive bone resorption, myeloma and bone metastases, and osteoporosis. They inhibit farnesyl pyrophosphate synthase (FFPS), a key enzyme in the mevalonate pathway, resulting in inhibition of the prenylation of small GTP-binding proteins in osteoclasts and disruption of their cytoskeleton, adhesion/spreading, and invasion of cancer cells. A very few examples for synthesis of α-amino bisphosphonates based on several amino acids are known from the literature. In the present work, esters of aminoacid react with ketophsophonate (or their analog acid or acyl) to afford the desired products, α-iminophosphonates. The reaction of imine with dimethyl phosphate in the presence of catalytic amount of I2 give ester of α-aminobisphosphonate as sole product in good yield. Finally, we used computational docking methods to predict how several α-aminobisphosphonates bind to FPPS and how R and X influence. Pamidronate, β-aminobisphosphonate already marketed, was used as reference. These results are of interest since they represent a new and simple way to sythesize α-aminobisphosphonates with a free COOH group increased by R2 functionalisable and opening up the possibility of using the molecular docking to facilitate the design of other, novel FFPS inhibitors.

Keywords: drug research, cancer, α-amino bisphosphonates, molecular docking

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Authors: Ihsan Al-Abboodi, Tahsin Toma-Sabbagh

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Laboratory tests have been carried out to investigate the response of 2x2 pile group subjected to triangular soil movement. The pile group was instrumented with displacement and tilting devices at the pile cap and strain gauges on two piles of the group. In this paper, results from four model tests were presented to study the effects of axial loads and soil density on the lateral behavior of piles. The responses in terms of bending moment, shear force, soil pressure, deflection, and rotation of piles were compared. Test results indicate that increasing the soil strength could increase the measured moment, shear, soil pressure, and pile deformations. Most importantly, adding loads to the pile cap induces additional moment to the head of front-pile row unlike the back-pile row which was influenced insignificantly.

Keywords: pile group, passive piles, lateral soil movement, soil density, axial loads

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Authors: Sira Suren, Soorathep Kheawhom

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This work investigates the development of a high energy density zinc-air battery. Printed and flexible thin film zinc-air battery with an overall thickness of about 350 μm was fabricated by an inexpensive screen-printing technique. Commercial nano-silver ink was used as both current collectors and catalyst layer. Carbon black ink was used to fabricate cathode electrode. Polypropylene membrane was used as the cathode substrate and separator. 9 M KOH was used as the electrolyte. A mixture of Zn powder, ZnO, and Bi2O3 was used to prepare the anode electrode. The suitable concentration of Bi2O3 and types of binders (styrene-butadiene and sodium silicate) were investigated. Results showed that battery using 20% Bi2O3 and sodium silicate binder provided the best performance. The open-circuit voltage and energy density observed were 1.59 V and 690 Wh/kg, respectively. When the battery was discharged at 20 mA/cm2, the potential voltage observed was 1.3 V. Furthermore, the battery was tested for its flexibility. Upon bending, no significant loss in performance was observed.

Keywords: flexible, printed battery, screen printing, Zn-air

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Authors: Ameur Soukaina, Zeroual Abdellah, Mazoir Noureddine

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Molecular Electron Density Theory (MEDT) elucidates the regioselectivity of the [4+2] cycloaddition reaction between 3-aroylpyrrolo[1,2-α]quinoxaline-1,2,4(5H)-trione and butyl vinyl ether Regioselectivity and stereoselectivity. The regioselectivity mechanisms of these reactions were investigated by evaluating potential energy surfaces calculated for cycloaddition processes and DFT density-based reactivity indices. These methods have been successfully applied to predict preferred regioisomers for different method alternatives. Reactions were monitored by performing transition state optimizations, calculations of intrinsic reaction coordinates, and activation energies. The observed regioselectivity was rationalized using DFT-based reactivity descriptors such as the Parr function. Solvent effects were also investigated in 1,4-dioxane solvent using a field model for self-consistent reactions. The results were compared with experimental data to find good agreement.

Keywords: cycloaddition, DFT, ELF, MEDT, parr, stereoselectivité

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Authors: Vineeth Siripuram, Abhineet Nigam

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A bioreactor is an engineered system that supports a biologically active environment. Along the years, the advancements in bioreactors have been widely accepted all over the world for varied applications ranging from sewage treatment to tissue cloning. Driven by tissue and organ shortage, tissue engineering has emerged as an alternative to transplantation for the reconstruction of lost or damaged organs. In this study, Computational fluid dynamics (CFD) has been used to model porous medium flow in scaffolds (taken from the literature) with different flow patterns. A detailed analysis of different scaffold geometries and their influence on cell deposition in the perfusion system is been carried out using Computational fluid dynamics (CFD). Considering the fact that, the scaffold should mimic the organs or tissues structures in a three-dimensional manner, certain assumptions were made accordingly. The research on scaffolds has been extensively carried out in different bioreactors. However, there has been less focus on the morphology of the scaffolds and the flow patterns in which the perfusion system is laid upon. The objective of this paper is to employ a computational approach using CFD simulation to determine the optimal morphology and the anisotropic measurements of the various samples of scaffolds. Using predictive computational modelling approach, variables which exert dominant effects on the cell deposition within the scaffold were prioritised and corresponding changes in morphology of scaffold and flow patterns in the perfusion systems are made. A Eulerian approach was carried on in multiple CFD simulations, and it is observed that the morphological and topological changes in the scaffold perfusion system are of great importance in the commercial applications of scaffolds.

Keywords: cell seeding, CFD, flow patterns, modelling, perfusion systems, scaffold

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Authors: Nuseiba M. Altarawneh, Suhuai Luo, Brian Regan, Guijin Tang

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Liver segmentation from medical images poses more challenges than analogous segmentations of other organs. This contribution introduces a liver segmentation method from a series of computer tomography images. Overall, we present a novel method for segmenting liver by coupling density matching with shape priors. Density matching signifies a tracking method which operates via maximizing the Bhattacharyya similarity measure between the photometric distribution from an estimated image region and a model photometric distribution. Density matching controls the direction of the evolution process and slows down the evolving contour in regions with weak edges. The shape prior improves the robustness of density matching and discourages the evolving contour from exceeding liver’s boundaries at regions with weak boundaries. The model is implemented using a modified distance regularized level set (DRLS) model. The experimental results show that the method achieves a satisfactory result. By comparing with the original DRLS model, it is evident that the proposed model herein is more effective in addressing the over segmentation problem. Finally, we gauge our performance of our model against matrices comprising of accuracy, sensitivity and specificity.

Keywords: Bhattacharyya distance, distance regularized level set (DRLS) model, liver segmentation, level set method

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Authors: Xilu Liu, Ameen Farooq

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Beijing has several compact residential housing settings in many of its urban districts. The study in this paper reveals that urban compactness, as predictor of density, may carry an altogether different meaning in the developing world when compared to the U.S for achieving objectives of urban sustainability. Recent urban design studies in the U.S are debating for compact and mixed-use higher density housing to achieve sustainable and energy efficient living environments. While the concept of urban compactness is widely accepted as an approach in modern architectural and urban design fields, this belief may not directly carry well into all areas within cities of developing countries. Beijing’s technology-driven economy, with its historic and rich cultural heritage and a highly speculated real-estate market, extends its urban boundaries into multiple compact urban settings of varying scales and densities. The accelerated pace of migration from the countryside for better opportunities has led to unsustainable and uncontrolled buildups in order to meet the growing population demand within and outside of the urban center. This unwarranted compactness in certain urban zones has produced an unhealthy physical density with serious environmental and ecological challenging basic living conditions. In addition, crowding, traffic congestion, pollution and limited housing surrounding this compactness is a threat to public health. Several residential blocks in close proximity to each other were found quite compacted, or ill-planned, with residential sites due to lack of proper planning in Beijing. Most of them at first sight appear to be compact and dense but further analytical studies revealed that what appear to be dense actually are not as dense as to make a good case that could serve as the corner stone of sustainability and energy efficiency. This study considered several factors including floor area ratio (FAR), ground coverage (GSI), open space ratio (OSR) as indicators in analyzing urban compactness as a predictor of density. The findings suggest that these measures, influencing the density of residential sites under study, were much smaller in density than expected given their compact adjacencies. Further analysis revealed that several residential housing appear to support the notion of density in its compact layout but are actually compacted due to unregulated planning marred by lack of proper urban design standards, policies and guidelines specific to their urban context and condition.

Keywords: Beijing, density, sustainability, urban compactness

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Authors: M. R. S. Nasuha, K. Azman, H. Azhan, S. A. Senawi, A. Mardhiah

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Studies on Samarium doped glasses possess lot of interest due to their potential applications for high-density optical memory, optical communication device, the design of laser and color display etc. Sm3+ doped borotellurite glasses of the system (70-x) TeO2-20B2O3-10ZnO-xSm2O3 (where x = 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol%) have been prepared using melt-quenching method. Their physical properties such as density, molar volume and oxygen packing density as well as the optical measurements by mean of their absorption and emission characteristic have been carried out at room temperature using UV/VIS and photoluminescence spectrophotometer. The results of physical properties are found to vary with respect to Sm3+ ions content. Meanwhile, three strong absorption peaks are observed and are well resolved in the ultra violet and visible regions due to transitions between the ground state and various excited state of Sm3+ ions. Thus, the photoluminescence spectra exhibit four emission bands from the initial state, which correspond to the 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, 4G5/2 → 6H9/2 and 4G5/2 → 6H11/2 fluorescence transitions at 562 nm, 599 nm, 645 nm and 706 nm respectively.

Keywords: absorption, borotellurite, down-conversion, emission

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Authors: Soheil Heydari, Ailar Hajimohammadi, Nasser Khalili

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The application of plastic waste for asphalt modification is a sustainable strategy to deal with the enormous plastic waste generated each year and enhance the properties of asphalt. The modification is either practiced by the dry process or the wet process. In the dry process, plastics are added straight into the asphalt mixture, and in the wet process, they are mixed and digested into bitumen. In this article, the effects of plastic inclusion in asphalt mixture, through the dry process, on the permanent deformation of the asphalt are investigated. The main waste plastics that are usually used in asphalt modification are taken into account, which is linear, low-density polyethylene, low-density polyethylene, high-density polyethylene, and polypropylene. Also, to simulate a plastic waste stream, different grades of each virgin plastic are mixed and used. For instance, four different grades of polypropylene are mixed and used as representative of polypropylene. A precisely designed mixing condition is considered to dry-mix the plastics into the mixture such that the polymer was melted and modified by the later introduced binder. In this mixing process, plastics are first added to the hot aggregates and mixed three times in different time intervals, then bitumen is introduced, and the whole mixture is mixed three times in fifteen minutes intervals. Marshall specimens were manufactured, and dynamic creep tests were conducted to evaluate the effects of modification on the permanent deformation of the asphalt mixture. Dynamic creep is a common repeated loading test conducted at different stress levels and temperatures. Loading cycles are applied to the AC specimen until failure occurs; with the amount of deformation constantly recorded, the cumulative, permanent strain is determined and reported as a function of the number of cycles. The results of this study showed that the dry inclusion of the waste plastics is very effective in enhancing the resistance against permanent deformation of the mixture. However, the mixing process must be precisely engineered to melt the plastics, and a homogenous mixture is achieved.

Keywords: permanent deformation, waste plastics, low-density polyethene, high-density polyethene, polypropylene, linear low-density polyethene, dry process

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Authors: Arka Roy, Chandra Prakash Dubey

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Inverse problem generally used for recovering hidden information from outside available data. Vertical component of gravity field we will be going to use for underneath density structure calculation. Ill-posing nature is main obstacle for any inverse problem. Linear regularization using Tikhonov formulation are used for appropriate choice of SVD and GSVD components. For real time data handle, signal to noise ratios should have to be less for reliable solution. In our study, 2D and 3D synthetic model with rectangular grid are used for gravity field calculation and its corresponding inversion for density reconstruction. Fine grid also we have considered to hold any irregular structure. Keeping in mind of algebraic ambiguity factor number of observation point should be more than that of number of data point. Picard plot is represented here for choosing appropriate or main controlling Eigenvalues for a regularized solution. Another important study is depth resolution plot (DRP). DRP are generally used for studying how the inversion is influenced by regularizing or discretizing. Our further study involves real time gravity data inversion of Vredeforte Dome South Africa. We apply our method to this data. The results include density structure is in good agreement with known formation in that region, which puts an additional support of our method.

Keywords: depth resolution plot, gravity inversion, Picard plot, SVD, Tikhonov formulation

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Authors: Haibin Zhou, Pingping Yao, Kunyang Fan

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Copper-based sintered friction materials are widely used in the brake system of different applications such as engineering machinery or high-speed train, due to the excellent mechanical, thermal and tribological performance. Considering the diversity of the working conditions of brake system, it is necessary to identify well and understand the tribological performance and wear mechanisms of friction materials for different conditions. Fe has been a preferred reinforcement for copper-based friction materials, due to its ability to improve the wear resistance and mechanical properties of material. Wear map is well accepted as a useful research method for evaluation of wear performances and wear mechanisms over a wider range of working conditions. Therefore, it is significantly important to construct a wear map which can give out the effects of work condition and Fe reinforcement on tribological performance of Cu-based friction materials. In this study, the copper-based sintered friction materials with the different addition of Fe reinforcement (0-20 vol. %) were studied. The tribological tests were performed against stainless steel in a ring-on-ring braking tester with varying braking energy density (0-5000 J/cm2). The linear wear and friction coefficient were measured. The worn surface, cross section and debris were analyzed to determine the dominant wear mechanisms for different testing conditions. On the basis of experimental results, the wear map and wear mechanism map were established, in terms of braking energy density and the addition of Fe. It was found that with low contents of Fe and low braking energy density, adhesive wear was the dominant wear mechanism of friction materials. Oxidative wear and abrasive wear mainly occurred under moderate braking energy density. In the condition of high braking energy density, with both high and low addition of Fe, delamination appeared as the main wear mechanism.

Keywords: Cu-based friction materials, Fe reinforcement, wear map, wear mechanism

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Authors: I. D. Laryushin, V. A. Kostin, A. A. Silaev, N. V. Vvedenskii

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Generation of broadband intense terahertz (THz) radiation attracts reasonable interest due to various applications, such as the THz time-domain spectroscopy, the probing and control of various ultrafast processes, the THz imaging with subwavelength resolution, and many others. One of the most promising methods for generating powerful and broadband terahertz pulses is based on focusing two-color femtosecond ionizing laser pulses in gases, including ambient air. For this method, the amplitudes of terahertz pulses are determined by the free-electron current density remaining in a formed plasma after the passage of the laser pulse. The excitation of this residual current density can be treated as multi-wave mixing: Аn effective generation of terahertz radiation is possible only when the frequency ratio of one-color components in the two-color pulse is close to irreducible rational fraction a/b with small odd sum a + b. This work focuses on the optimal parameters (polarizations and intensities) of laser components for the strongest THz generation. The optimal values of parameters are found numerically and analytically with the use of semiclassical approach for calculating the residual current density. For frequency ratios close to a/(a ± 1) with natural a, the strongest THz generation is shown to take place when the both laser components have circular polarizations and equal intensities. For this optimal case, an analytical formula for the residual current density was derived. For the frequency ratios such as 2/5, the two-color ionizing pulses with circularly polarized components practically do not excite the residual current density. However, the optimal parameters correspond generally to specific elliptical (not linear) polarizations of the components and intensity ratios close to unity.

Keywords: broadband terahertz radiation, ionization, laser plasma, ultrashort two-color pulses

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Authors: Dinesh Kumar Maurya, Sapan Mohan Saini

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A theoretical formalism to calculate the structural, electronic and optical properties of orthorhombic crystals from first principle calculations is described. This is applied first time to new YNi4Si-type DyNi4Si compound. Calculations are performed using full-potential augmented plane wave (FPLAPW) method in the framework of density functional theory (DFT). The Coulomb corrected local-spin density approximation (LSDA+U) in the self-interaction correction (SIC) has been used for exchange-correlation potential. Our optimized results of lattice parameters show good agreement to the previously reported experimental study. Analysis of the calculated band structure of DyNi4Si compound demonstrates their metallic character. We found Ni-3d states mainly contribute to density of states from -5.0 eV to the Fermi level while the Dy-f states peak stands tall in comparison to the small contributions made by the Ni-d and R-d states above Fermi level, which is consistent with experiment, in DNi4Si compound. Our calculated optical conductivity compares well with the experimental data and the results are analyzed in the light of band-to-band transitions. We also report the frequency-dependent refractive index n(ω) and the extinction coefficient k(ω) of the compound.

Keywords: band structure, density of states, optical properties, LSDA+U approximation, YNi4Si- type DyNi4Si compound

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Authors: A. Katsman, L. Bloch, Y. Etinger, Y. Kauffmann, B. Pokroy

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Various nanosized amorphous alumina thin films in the range of (2.4 - 63.1) nm were deposited onto amorphous carbon and amorphous Si3N4 membrane grids. Transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS) and differential scanning calorimetry (DSC) techniques were used to probe the size effect on the short range order and the amorphous to crystalline phase transition temperature. It was found that the short-range order changes as a function of size: the fraction of tetrahedral Al sites is greater in thinner amorphous films. This result correlates with the change of amorphous alumina density with the film thickness demonstrated by the reflectivity experiments: the thinner amorphous films have the less density. These effects are discussed in terms of surface reconstruction of the amorphous alumina films. The average atomic binding energy in the thin film layer decreases with decease of the thickness, while the average O-Al interatomic distance increases. The reconstruction of amorphous alumina is induced by the surface reconstruction, and the short range order changes being dependent on the density. Decrease of the surface energy during reconstruction is the driving force of the alumina reconstruction (density change) followed by relaxation process (short range order change). The amorphous to crystalline phase transition temperature measured by DSC rises with the decrease in thickness from 997.6°C for 13.9 nm to 1020.4 °C for 2.7 nm thick. This effect was attributed to the different film densities: formation of nanovoids preceding and accompanying crystallization process influences the crystallization rate, and by these means, the temperature of crystallization peak.

Keywords: amorphous alumina, density, short range order, size effect

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Authors: M. Imran Hossen Khan, M. Mahiuddin, M. A. Karim

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Drying is a food processing technique where simultaneous heat and mass transfer take place from surface to the center of the sample. Deformation of food materials during drying is a common physical phenomenon which affects the textural quality and taste of the dried product. Most of the plant-based food materials are porous and hygroscopic in nature that contains about 80-90% water in different cellular environments: intercellular environment and intracellular environment. Transport of this cellular water has a significant effect on material deformation during drying. However, understanding of the scale of deformation is very complex due to diverse nature and structural heterogeneity of food material. Knowledge about the effect of transport of cellular water on deformation of material during drying is crucial for increasing the energy efficiency and obtaining better quality dried foods. Therefore, the primary aim of this work is to investigate the effect of intracellular water transport on material deformation during drying. In this study, apple tissue was taken for the investigation. The experiment was carried out using 1H-NMR T2 relaxometry with a conventional dryer. The experimental results are consistent with the understanding that transport of intracellular water causes cellular shrinkage associated with the anisotropic deformation of whole apple tissue. Interestingly, it is found that the deformation of apple tissue takes place at different stages of drying rather than deforming at one time. Moreover, it is found that the penetration rate of heat energy together with the pressure gradient between intracellular and intercellular environments is the responsible force to rupture the cell membrane.

Keywords: heat and mass transfer, food material, intracellular water, cell rupture, deformation

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Authors: M. S. Gaafar, S. Y. Marzouk, I. S. Mahmoud, S. Al-Zobaidi

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Makishima and Mackenzie model was used to simulation of acoustic properties (longitudinal and shear ultrasonic wave velocities, elastic moduli theoretically for many tellurite and borate glasses. The model was proposed mainly depending on the values of the experimentally measured density, which are obtained before. In this search work, we are trying to obtain the values of densities of amorphous glasses (as the density depends on the geometry of the network structure of these glasses). In addition, the problem of simulating the slope of linear regression between the experimentally determined bulk modulus and the product of packing density and experimental Young's modulus, were solved in this search work. The results showed good agreement between the experimentally measured values of densities and both ultrasonic wave velocities, and those theoretically determined.

Keywords: glasses, ultrasonic wave velocities, elastic modulus, Makishima & Mackenzie Model

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Authors: Xvelian Qin

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Urban "organic renewal" based on the development of existing resources in high-density urban areas has become the mainstream of urban development in the new era. As an important stock resource of public space in high-density urban areas, promoting its value remodeling is an effective way to alleviate the shortage of public space resources. However, due to the lack of evaluation links in the process of underpass space renewal, a large number of underpass space resources have been left idle, facing the problems of low space conversion efficiency, lack of accuracy in development decision-making, and low adaptability of functional positioning to citizens' needs. Therefore, it is of great practical significance to construct the evaluation system of under-bridge space renewal potential and explore the renewal mode. In this paper, some of the under-bridge spaces in the main urban area of Chongqing are selected as the research object. Through the questionnaire interviews with the users of the built excellent space under the bridge, three types of six levels and twenty-two potential evaluation indexes of "objective demand factor, construction feasibility factor and construction suitability factor" are selected, including six levels of land resources, infrastructure, accessibility, safety, space quality and ecological environment. The analytical hierarchy process and expert scoring method are used to determine the index weight, construct the potential evaluation system of the space under the bridge in high-density urban areas of Chongqing, and explore the direction of renewal and utilization of its suitability.

Keywords: space under bridge, potential evaluation, high density urban area, updated using

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Authors: Akbar Cahyadhi Pratama Putra, Tantri Utami Widhaningtyas, M. Randy Aswin

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Indonesia as an archipelagic nation have very long coastline which have large potential marine resources, one of that is the mangrove ecosystems. Lapindo mudflow disaster in Sidoarjo, East Java requires mudflow flowed into the sea through the river Brantas and Porong. Mud material that transported by river flow is feared dangerous because they contain harmful substances such as heavy metals. This study aims to map the mangrove ecosystem seen from its density and knowing how big the impact of a disaster on the Lapindo mud to mangrove ecosystem and accompanied by efforts to address the mangrove ecosystem that maintained continuity. Mapping coastal mangrove conditions of Sidoarjo was done using remote sensing products that Landsat 7 ETM + images with dry months of recording time in 2002, 2006, 2009, and 2014. The density of mangrove detected using NDVI that uses the band 3 that is the red channel and band 4 that is near IR channel. Image processing was used to produce NDVI using ENVI 5.1 software. NDVI results were used for the detection of mangrove density is 0-1. The development of mangrove ecosystems of both area and density from year to year experienced has a significant increase. Mangrove ecosystems growths are affected by material deposition area of Lapindo mud on Porong and Brantas river estuary, where the silt is growing medium suitable mangrove ecosystem and increasingly growing. Increasing the density caused support by public awareness to prevent heavy metals in the material so that the Lapindo mud mangrove breeding done around the farm.

Keywords: archipelagic nation, mangrove, Lapindo mudflow disaster, NDVI

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Authors: Khalil Abdullah Ahmed Khalil, Elsadig Mohamed Ahmed

Abstract:

Extracts of various plants material capable of decreasing blood sugar have been tested in experimental animal models and their effects confirmed. Neem or Margose (Azadirachta Indica) is an indigenous plant believed to have antiviral, antifungal, antidiabetic and many other properties. This paper deals with a comparative study of the effect of aqueous Neem leaves extract alone or in combination with glibenclamide on alloxan diabetic rabbits. Administration of crude aqueous Neem extract (CANE) alone (1.5 ml/kg/day), as well as the combination of CANE (1.5 ml/kg/day) with glibenclamide (0.25 mg/kg/day) significantly, decreased (P<0.05) the concentrations of serum lipids, blood glucose and lipoprotein VLDL(very low-density lipoproteins) and LDL(low-density lipoproteins) but significantly increased (P<0.05) the concentration of HDL(high-density lipoprotein). The change was observed significantly greater when the treatment was given in combination of CANE and glibenclamid than with CANE alone.

Keywords: neem, hypoglycemic, hypolipidemic, cholesterol

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Authors: Stephanie Cheng, Benjamin Poh, Vivyan Tay, Sachin Mathur

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Aim: Diabetes mellitus (DM) is a worldwide pandemic affecting 500 million people. It is known to be associated with increased susceptibility to soft tissue infections (STI). Despite being a major public health burden, the literature relating the effects of DM and the presentation, severity and healing of STIs in general surgical patients remain limited. Methods: We conducted a retrospective review of all patients admitted with STI in a tertiary teaching hospital over a 12-month period. Patient demographics and surgical outcomes were collected and analyzed. Results: During the study period, 1059 patients were admitted for STIs, of which 936 (88%) required surgical intervention. Diabetic patients were presented with a higher body-mass index (BMI) (28 vs 26), larger abscess size (24 vs 14 cm²) and a longer length of stay (LOS)(4.4 days vs 2.9 days). They also underwent a higher proportion of wide debridement as well as application of negative pressure wound therapy (NPWT) (42% vs 35%). More diabetic patients underwent subsequent re-operation within the same sitting (8 vs 4). There were no differences in re-admission rates within 30 days nor subsequent abscess formation in those followed for 6 months. Conclusion: The incidence of STIs among DM patients represents a significant disease burden; surgeons should consider intensive patient counseling and partnering with primary care providers in order to help reduce the incidence of future STI admissions based on lifestyle modification and glucose control.

Keywords: general surgery, emergency general surgery, acute care surgery, soft tissue infections, diabetes mellitus

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Authors: Sara Mosallanejad, Bogdan Z. Dlugogorski, Jeff Gore, Mohammednoor Altarawneh

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Ammonium nitrate (NH­₄NO₃, AN) is commonly used as the main component of AN emulsion and fuel oil (ANFO) explosives, that use extensively in civilian and mining operations for underground development and tunneling applications. The emulsion formulation and wettability of AN prills, which affect the physical stability and detonation of ANFO, highly depend on the surface tension, density, viscosity of the used liquid. Therefore, for engineering applications of this material, the determination of density and surface tension of concentrated aqueous solutions of AN is essential. The molecular dynamics (MD) simulation method have been used to investigate the density and the surface tension of high concentrated ammonium nitrate solutions; up to its solubility limit in water. Non-polarisable models for water and ions have carried out the simulations, and the electronic continuum correction model (ECC) uses a scaling of the charges of the ions to apply the polarisation implicitly into the non-polarisable model. The results of calculated density and the surface tension of the solutions have been compared to available experimental values. Our MD simulations show that the non-polarisable model with full-charge ions overestimates the experimental results while the reduce-charge model for the ions fits very well with the experimental data. Ions in the solutions show repulsion from the interface using the non-polarisable force fields. However, when charges of the ions in the original model are scaled in line with the scaling factor of the ECC model, the ions create a double ionic layer near the interface by the migration of anions toward the interface while cations stay in the bulk of the solutions. Similar ions orientations near the interface were observed when polarisable models were used in simulations. In conclusion, applying the ECC model to the non-polarisable force field yields the density and surface tension of the AN solutions with high accuracy in comparison to the experimental measurements.

Keywords: ammonium nitrate, electronic continuum correction, non-polarisable force field, surface tension

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Authors: Jae-Yong Park, Gwancheol Seo, Young-Ho Kim

Abstract:

Microvoids, sometimes called Kikendall voids, generally form in the interfaces between Sn-based solders and Cu and degrade the mechanical and electrical properties of the solder joints. The microvoid formation is known as the rapid interdiffusion between Sn and Cu and impurity content in the Cu. Cu electroplating from the acid solutions has been widely used by microelectronic packaging industry for both printed circuit board (PCB) and integrated circuit (IC) applications. The quality of electroplated Cu that can be optimized by the electroplating conditions is critical for the solder joint reliability. In this paper, the influence of electroplating conditions on the microvoid growth in the interfaces between Sn-3.0Ag-0.5Cu (SAC) solder and Cu layer was investigated during isothermal aging. The Cu layers were electroplated by controlling the additive of electroplating bath and current density to induce various microvoid densities. The electroplating bath consisted of sulfate, sulfuric acid, and additives and the current density of 5-15 mA/cm2 for each bath was used. After aging at 180 °C for up to 250 h, typical bi-layer of Cu6Sn5 and Cu3Sn intermetallic compounds (IMCs) was gradually growth at the SAC/Cu interface and microvoid density in the Cu3Sn showed disparities in the electroplating conditions. As the current density increased, the microvoid formation was accelerated in all electroplating baths. The higher current density induced, the higher impurity content in the electroplated Cu. When the polyethylene glycol (PEG) and Cl- ion were mixed in an electroplating bath, the microvoid formation was the highest compared to other electroplating baths. On the other hand, the overall IMC thickness was similar in all samples irrespective of the electroplating conditions. Impurity content in electroplated Cu influenced the microvoid growth, but the IMC growth was not affected by the impurity content. In conclusion, the electroplated conditions are properly optimized to avoid the excessive microvoid formation that results in brittle fracture of solder joint under high strain rate loading.

Keywords: electroplating, additive, microvoid, intermetallic compound

Procedia PDF Downloads 247

Authors: Serge Provost, Yishan Zang

Abstract:

Copulas are currently utilized in finance, reliability theory, machine learning, signal processing, geodesy, hydrology and biostatistics, among several other fields of scientific investigation. It follows from Sklar's theorem that the joint distribution function of a multidimensional random vector can be expressed in terms of its associated copula and marginals. Since marginal distributions can easily be determined by making use of a variety of techniques, we address the problem of securing the distribution of the copula. This will be done by using several approaches. For example, we will obtain bivariate least-squares approximations of the empirical copulas, modify the kernel density estimation technique and propose a criterion for selecting appropriate bandwidths, differentiate linearized empirical copulas, secure Bernstein polynomial approximations of suitable degrees, and apply a corollary to Sklar's result. Illustrative examples involving actual observations will be presented. The proposed methodologies will as well be applied to a sample generated from a known copula distribution in order to validate their effectiveness.

Keywords: copulas, Bernstein polynomial approximation, least-squares polynomial approximation, kernel density estimation, density approximation

Procedia PDF Downloads 61

Authors: M. Ekiert, T. Uhl, A. Mlyniec

Abstract:

Tendons are the biological soft tissue structures composed of collagen, proteoglycan, glycoproteins, water and cells of extracellular matrix (ECM). Tendons, which primary function is to transfer force generated by the muscles to the bones causing joints movement, are exposed to many micro and macro damages. In fact, tendons and ligaments trauma are one of the most numerous injuries of human musculoskeletal system, causing for many people (particularly for athletes and physically active people), recurring disorders, chronic pain or even inability of movement. The number of tendons reconstruction and transplantation procedures is increasing every year. Therefore, studies on soft tissues storage conditions (influencing i.e. tissue aging) seem to be an extremely important issue. In this study, an atomic-scale investigation on the kinetics of decomposition of two selected tendon components – collagen type I (which forms a 60-85% of a tendon dry mass) and elastin protein (which combine with ECM creates elastic fibers of connective tissues) is presented. A molecular model of collagen and elastin was developed based on crystal structure of triple-helical collagen-like 1QSU peptide and P15502 human elastin protein, respectively. Each model employed 4 linear strands collagen/elastin strands per unit cell, distributed in 2x2 matrix arrangement, placed in simulation box filled with water molecules. A decomposition phenomena was simulated with molecular dynamics (MD) method using ReaxFF force field and periodic boundary conditions. A set of NVT-MD runs was performed for 1000K temperature range in order to obtained temperature-depended rate of production of decomposition by-products. Based on calculated reaction rates activation energies and pre-exponential factors, required to formulate Arrhenius equations describing kinetics of decomposition of tested soft tissue components, were calculated. Moreover, by adjusting a model developed for collagen, system scalability and correct implementation of the periodic boundary conditions were evaluated. An obtained results provide a deeper insight into decomposition of selected tendon components. A developed methodology may also be easily transferred to other connective tissue elements and therefore might be used for further studies on soft tissues aging.

Keywords: decomposition, molecular dynamics, soft tissue, tendons

Procedia PDF Downloads 203

Authors: Fatima Mehmood, Khalid Farooq, Rabeea Bakhtawer

Abstract:

For geotechnical engineers, one of the most important properties of soil to consider in various stability analyses is its shear strength which is governed by a number of factors. The objective of this research is to ascertain the effect of compaction and degree of saturation on the shear strength of fine-grained soil. For this purpose, three different dry densities such as in-situ, maximum standard proctor, and maximum modified proctor, were determined for the sandy clay soil. The soil samples were then prepared to keep dry density constant and varying degrees of saturation. These samples were tested for (UU) unconsolidated undrained shear strength in triaxial compression tests. The decrease in shear strength was observed with the decrease in density and increase in the saturation. The values of the angle of internal friction followed the same trend. However, the change in cohesion with the increase in saturation showed a different behavior, analogous to the compaction curve.

Keywords: compaction, degree of saturation, dry density, geotechnical investigation, laboratory testing, shear strength

Procedia PDF Downloads 127

Authors: Govind Sharma, Bahni Ray

Abstract:

Ubiquitous nature of particle settling is governed by the presence of the surrounding fluid medium. Thermally stratified fluid alters the settling phenomenon of particles as well as their interactions. Direct numerical simulation (DNS) is carried out with an open-source library Immersed Boundary Adaptive Mesh Refinement (IBAMR) to quantify the fundamental mechanism based on Distributed Lagrangian Multiplier (DLM). The presence of background density gradient due to thermal stratification replaces the drafting-kissing-tumbling in a homogeneous fluid to drafting-kissing-separation behavior. Simulations are performed with a varying range of particle-fluid density ratios, and it is shown that the stratification effect on particle interactions varies with density ratio. It is observed that the combined role of buoyancy and inertia govern the physical mechanism of particle-particle interaction.

Keywords: direct numerical simulation, distributed lagrangian multiplier, rigidity constraint, sedimentation, stratification

Procedia PDF Downloads 128

Authors: Akshita Bhardwaj

Abstract:

Keratinase is an enzyme obtained from extracellular sources that is involved in biodegradation of keratin. It is a member of a group of proteases that can break down keratin into amino acids. Keratinases are produced only in the presence of substrate that contain keratin. It attacked the disulfide bond of substrate and involve in keratin degradation. Human hair, feathers, animal hard tissues, horns, claws, and hooves all contain keratin.. It exists in two form alpha keratin (found in soft tissues) and beta keratin (found in hard tissue). By taking part in the degradation of keratin, keratinases derived from microbial sources, often referred to as microbial keratinases, are important in the process of turning wastes containing keratin into products with added value. Chicken feathers contain high level of keratin protein content than other sources and became a suitable protein source. Keratinase production occurs at near alkaline pH and thermophilic temperatures. The bioprocessing of keratinous waste benefits greatly from the use of keratinases. Additionally, it lessens the issue caused by poultry excrement. The use of feather meal, along with keratinase, improves the digestion of proteins and amino acids.

Keywords: mili litre (ml), micro litre (Ul), TCA - trichloroacetic acid, OD - optical density

Procedia PDF Downloads 71

Authors: Dhyaalddin Bahaalddin Noori Zangana

Abstract:

This study involves the behavior of reinforced sand under a square footing. A series of bearing capacity tests were performed on a small-scale laboratory model, which filled with a poorly-graded homogenous bed of sand, which was placed in a medium dense state using sand raining technique. The sand was reinforced with 40 mm wide household aluminum foil strips. The main studied parameters was to consider the effect of reinforcing strip length, with various linear density of reinforcement, number of reinforcement layers and depth of top layer of reinforcement below the footing, on load-settlement behavior, bearing capacity ratio and settlement reduction factor. The relation of load-settlement generally showed similar trend in all the tests. Failure was defined as settlement equal to 10% of the footing width. The recommended optimum reinforcing strip length, linear density of reinforcement, number of reinforcement layers and depth of top layer of reinforcing strips that give the maximum bearing capacity improvement and minimum settlement reduction factor were presented and discussed. Different bearing capacity ration versus length of the reinforcing strips and settlement reduction factor versus length of the reinforcing strips relations at failure were showed improvement of bearing capacity ratio by a factor of 3.82 and reduction of settlement reduction factor by a factor of 0.813. The optimum length of reinforcement was found to be 7.5 times the footing width.

Keywords: square footing, relative density, linear density of reinforcement, bearing capacity ratio, load-settlement behaviour

Procedia PDF Downloads 90