Search results for: density estimation

Authors: Mohammad Shafiul Alam, Mineo Saito

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Graphene-based materials have attracted much attention because they are candidates for post silicon materials. Since controlling of impurities is necessary to achieve nano device, we study hydrogen impurity in multi-layer graphene. We perform local spin Density approximation (LSDA) in which the plane wave basis set and pseudopotential are used. Previously hydrogen monomer and dimer in graphene is well theoretically studied. However, hydrogen on multilayer graphene is still not clear. By using first-principles electronic structure calculations based on the LSDA within the density functional theory method, we studied hydrogen monomers and dimers in two-layer graphene. We found that the monomers are spin-polarized and have magnetic moment 1 µB. We also found that most stable dimer is much more stable than monomer. In the most stable structures of the dimers in two-layer graphene, the two hydrogen atoms are bonded to the host carbon atoms which are nearest-neighbors. In this case two hydrogen atoms are located on the opposite sides. Whereas, when the two hydrogen atoms are bonded to the same sublattice of the host materials, magnetic moments of 2 µB appear in two-layer graphene. We found that when the two hydrogen atoms are bonded to third-nearest-neighbor carbon atoms, the electronic structure is nonmagnetic. We also studied hydrogen monomers and dimers in three-layer graphene. The result is same as that of two-layer graphene. These results are very important in the field of carbon nanomaterials as it is experimentally difficult to show the magnetic state of those materials.

Keywords: first-principles calculations, LSDA, multi-layer gra-phene, nanomaterials

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Authors: Oluwagbenga B. Fatile, Felix U. Idu, Olajide T. Sanya

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This paper reports the viability of developing Zn-27Al alloy matrix hybrid composites reinforced with alumina, graphite and fly ash (a solid waste byproduct of coal in thermal power plants). This research work was aimed at developing low cost-high performance Zn-27Al matrix composite with low density. Alumina particulates (Al2O3), graphite added with 0, 2, 3, 4, and 5 wt% fly ash were utilized to prepare 10wt% reinforcing phase with Zn-27Al alloy as matrix using two-step stir casting method. Density measurement estimated percentage porosity, tensile testing, micro hardness measurement, and optical microscopy were used to assess the performance of the composites produced. The results show that the hardness, ultimate tensile strength, and percent elongation of the hybrid composites decrease with increase in fly ash content. The maximum decrease in hardness and ultimate tensile strength of 13.72% and 15.25% respectively were observed for composite grade containing 5wt% fly ash. The percentage elongation of composite sample without fly ash is 8.9% which is comparable with that of the sample containing 2wt% fly ash with percentage elongation of 8.8%. The fracture toughness of the fly ash containing composites was, however, superior to those of composites without fly ash with 5wt% fly ash containing composite exhibiting the highest fracture toughness. The results show that fly ash can be utilized as complementary reinforcement in ZA-27 alloy matrix composite to reduce cost.

Keywords: fly ash, hybrid composite, mechanical behaviour, stir-cast

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Authors: T. Weber, D. MacKenzie

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The script in this paper describes the use of advanced simulation environment using electronic systems (microcontroller, operational amplifiers, and FPGA). The simulation was used for non-linear dynamic systems behaviour with required observer structure working with parallel real-time simulation based on state-space representation. The proposed deposited model was used for electrodynamic effects including ionising effects and eddy current distribution also. With the script and proposed method, it is possible to calculate the spatial distribution of the electromagnetic fields in real-time and such systems. For further purpose, the spatial temperature distribution may also be used. With upon system, the uncertainties and disturbances may be determined. This provides the estimation of the more precise system states for the required system and additionally the estimation of the ionising disturbances that arise due to radiation effects in space systems. The results have also shown that a system can be developed specifically with the real-time calculation (estimation) of the radiation effects only. Electronic systems can take damage caused by impacts with charged particle flux in space or radiation environment. TID (Total Ionising Dose) of 1 Gy and Single Effect Transient (SET) free operation up to 50 MeVcm²/mg may assure certain functions. Single-Event Latch-up (SEL) results on the placement of several transistors in the shared substrate of an integrated circuit; ionising radiation can activate an additional parasitic thyristor. This short circuit between semiconductor-elements can destroy the device without protection and measurements. Single-Event Burnout (SEB) on the other hand, increases current between drain and source of a MOSFET and destroys the component in a short time. A Single-Event Gate Rupture (SEGR) can destroy a dielectric of semiconductor also. In order to be able to react to these processes, it must be calculated within a shorter time that ionizing radiation and dose is present. For this purpose, sensors may be used for the realistic evaluation of the diffusion and ionizing effects of the test system. For this purpose, the Peltier element is used for the evaluation of the dynamic temperature increases (dT/dt), from which a measure of the ionization processes and thus radiation will be detected. In addition, the piezo element may be used to record highly dynamic vibrations and oscillations to absorb impacts of charged particle flux. All available sensors shall be used to calibrate the spatial distributions also. By measured value of size and known location of the sensors, the entire distribution in space can be calculated retroactively or more accurately. With the formation, the type of ionisation and the direct effect to the systems and thus possible prevent processes can be activated up to the shutdown. The results show possibilities to perform more qualitative and faster simulations independent of space-systems and radiation environment also. The paper gives additionally an overview of the diffusion effects and their mechanisms.

Keywords: cattle, biochar, manure, microbial activity

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Authors: Hamid Mustafa, Huson J. Heather, Kim Eiusoo, McClure Matt, Khalid Javed, Talat Nasser Pasha, Afzal Ali1, Adeela Ajmal, Tad Sonstegard

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Genetic differences associated with speciation, breed formation or local adaptation can help to preserve and effective utilization of animals in selection programs. Analyses of population structure and breed diversity have provided insight into the origin and evolution of cattle. In this study, we used a high-density panel of SNP markers to examine population structure and diversity among ten Pakistani indigenous cattle breeds. In total, 25 individuals from three cattle populations, including Achi (n=08), Bhagnari (n=04) and Cholistani (n=13) were genotyped for 777, 962 single nucleotide polymorphism (SNP) markers. Population structure was examined using the linkage model in the program STRUCTURE. After characterizing SNP polymorphism in the different populations, we performed a detailed analysis of genetic structure at both the individual and population levels. The whole-genome SNP panel identified several levels of population substructure in the set of examined cattle breeds. We further searched for spatial patterns of genetic diversity among these breeds under the recently developed spatial principal component analysis framework. Overall, such high throughput genotyping data confirmed a clear partitioning of the cattle genetic diversity into distinct breeds. The resulting complex historical origins associated with both natural and artificial selection have led to the differentiation of numerous different cattle breeds displaying a broad phenotypic variety over a short period of time.

Keywords: Pakistan, cattle, genetic diversity, population structure

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Authors: Shokooh Moghadam, Mohammad Taghi Khorasani, Sajjad Seifi Mofarah, M. Daliri

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Through the recent two decades, the use of magnetic-property materials with the aim of target cell’s separation and eventually cancer treatment has incredibly increased. Numerous factors can alter the efficacy of this method on curing. In this project, the effect of magnetic field on adhesion of PDL and L929 cells on nanocomposite of iron oxide/PHB with different density of iron oxides (1%, 2.5%, 5%) has been studied. The nanocamposite mentioned includes a polymeric film of poly hydroxyl butyrate and γ-Fe2O3 particles with the average size of 25 nanometer dispersed in it and during this process, poly vinyl alcohol with 98% hydrolyzed and 78000 molecular weight was used as an emulsion to achieve uniform distribution. In order to get the homogenous film, the solution of PHB and iron oxide nanoparticles were put in a dry freezer and in liquid nitrogen, which resulted in a uniform porous scaffold and for removing porosities a 100◦C press was used. After the synthesis of a desirable nanocomposite film, many different tests were performed, First, the particles size and their distribution in the film were evaluated by transmission electron microscopy (TEM) and even FTIR analysis and DMTA test were run in order to observe and accredit the chemical connections and mechanical properties of nanocomposites respectively. By comparing the graphs of case and control samples, it was established that adding nano particles caused an increase in crystallization temperature and the more density of γ-Fe2O3 lead to more Tg (glass temperature). Furthermore, its dispersion range and dumping property of samples were raised up. Moreover, the toxicity, morphologic changes and adhesion of fibroblast and cancer cells were evaluated by a variety of tests. All samples were grown in different density and in contact with cells for 24 and 48 hours within the magnetic fields of 2×10^-3 Tesla. After 48 hours, the samples were photographed with an optic and SEM and no sign of toxicity was traced. The number of cancer cells in the case of sample group was fairly more than the control group. However, there are many gaps and unclear aspects to use magnetic field and their effects in cancer and all diseases treatments yet to be discovered, not to neglect that there have been prominent step on this way in these recent years and we hope this project can be at least a minimum movement in this issue.

Keywords: nanocomposite, cell attachment, magnetic field, cytotoxicity

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Authors: Pooja Verma, Rajnesh Tyagi, Sunil Mohan

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Al-Si alloys are widely used in various components such as liner-less engine blocks, piston, compressor bodies and pumps for automobile sector and aerospace industries due to their excellent combination of properties like low thermal expansion coefficient, low density, excellent wear resistance, high corrosion resistance, excellent cast ability, and high hardness. The low density and high hardness of primary Si phase results in significant reduction in density and improvement in wear resistance of hypereutectic Al-Si alloys. Keeping in view of the industrial importance of the alloys, hypereutectic Al-Si alloys containing 14, 16, 18 and 20 wt. % of Si were prepared in a resistance furnace using adequate amount of deoxidizer and degasser and their erosion behavior was evaluated by conducting tests at impingement angles of 30°, 60°, and 90° with an erodent discharge rate of 7.5 Hz, pressure 1 bar using erosion test rig. Microstructures of the cast alloys were examined using Optical microscopy (OM) and scanning electron microscopy (SEM) and the presence of Si particles was confirmed by x-ray diffractometer (XRD). The mechanical properties and hardness were measured using uniaxial tension tests at a strain rate of 10-3/s and Vickers hardness tester. Microstructures of the alloys and X-ray examination revealed the presence of primary and eutectic Si particles in the shape of cuboids or polyhedral and finer needles. Yield strength (YS), ultimate tensile strength (UTS), and uniform elongation of the hypereutectic Al-Si alloys were observed to increase with increasing content of Si. The optimal strength and ductility was observed for Al-20 wt. % Si alloy which is significantly higher than the Al-14 wt. % Si alloy. The increased hardness and the strength of the alloys with increasing amount of Si has been attributed presence of Si in the solid solution which creates strain, and this strain interacts with dislocations resulting in solid-solution strengthening. The interactions between distributed primary Si particles and dislocations also provide Orowan strengthening leading to increased strength. The steady state erosion rate was found to decrease with increasing angle of impact as well as Si content for all the alloys except at 900 where it was observed to increase with the increase in the Si content. The minimum erosion rate is observed in Al-20 wt. % Si alloy at 300 and 600 impingement angles because of its higher hardness in comparison to other alloys. However, at 90° impingement angle the wear rate for Al-20 wt. % Si alloy is found to be the minimum due to deformation, subsequent cracking and chipping off material.

Keywords: Al-Si alloy, erosion wear, cast alloys, dislocation, strengthening

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Authors: Eqbal M. A. Dauqan, A. Aminah

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The aim of the present study was to evaluate the blood lipid profile and liver lipid peroxidation in normal rat fed with different concentrations of Acacia senegal and Acacia seyal. Thirty six Sprague Dawley male rats each weighing between 180-200g were randomly divided into two groups. Each group contains eighteen rats and were divided into three groups of 6 rats per group. The rats were fed ad libitum with commercial rat’s feed and tap water containing different concentrations of Acacia senegal and Acacia seyal (3% and 6%) for 4 weeks. The results at 4 weeks showed that there was no significant difference (p≤0.05) in the total cholesterol (TC) and triglycerides (TG) between the control group and treated groups while the results for the high density lipoprotein (HDL-C) showed a significant decrease (P≥0.05) at the 3% and 6% of gum arabic treated groups compared to control group. There was a significant increase (P≥0.05) in low density lipoprotein (LDL-C) with 3% and 6% of gum Arabic (GA) groups compared to the control group. The study indicated that there was no significant (p≤0.05) effect on TC and TG but there was significant effect (P≥0.05) on HDL-C and LDL-C in blood lipid profile of normal rat. The results showed that after 4 weeks of treatment the malondialdehyde (MDA) value in rat fed with 6% of A. seyal group was significantly higher (P≥0.05) than control or other treated groups of A. seyal and A. senegal studied. Thus, the two species of gum arabic did not have beneficial effect on blood lipid profile and lipid peroxidation.

Keywords: Acacia senegal, acacia seyal, lipid profile, lipid peroxidation, malondialdehyde (MDA)

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Authors: T. Topór, A. Derkowski, P. Ziemiański

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Formation of organic matter (OM)-hosted nanopores upon thermal maturation are one of the key factor controlling methane storage potential in unconventional shale-gas reservoirs. In this study, the subcritical CO₂ and N₂ gas adsorption measurements combined with scanning electron microscopy and supercritical methane adsorption have been used to characterize pore system and methane storage potential in black shales from the Baltic Basin (Poland). The samples were collected from a virtually equivalent Llandovery strata across the basin and represent a complete digenetic sequence, from thermally immature to overmature. The results demonstrate that the thermal maturation is a dominant mechanism controlling the formation of OM micro- and mesopores in the Baltic Basin shales. The formation of micro- and mesopores occurs in the oil window (vitrinite reflectance; leavedVR; ~0.5-0.9%) as a result of oil expulsion from kerogenleft OM highly porous. The generated hydrocarbons then turn into solid bitumen causing pore blocking and substantial decrease in micro- and mesopore volume in late-mature shales (VR ~0.9-1.2%). Both micro- and mesopores are regenerated in a middle of the catagenesis range (VR 1.4-1.9%) due to secondary cracking of OM and gas formation. The micropore volume in investigated shales is almost exclusively controlled by the OM content. The contribution of clay minerals to micropore volume is insignificant and masked by a strong contribution from OM. Methane adsorption capacity in the Baltic Basin shales is predominantly controlled by microporous OM with pores < 1.5 nm. The mesopore volume (2-50 nm) and mesopore surface area have no effect on methane sorption behavior. The adsorbed methane density equivalent, calculated as absolute methane adsorption divided by micropore volume, reviled a decrease of the methane loading potential in micropores with increasing maturity. The highest methane loading potential in micropores is observed for OM before metagenesis (VR < 2%), where the adsorbed methane density equivalent is greater than the density of liquid methane. This implies that, in addition to physical adsorption, absorption of methane in OM may occur before metagenesis. After OM content reduction using NaOCl solution methane adoption capacity substantially decreases, suggesting significantly greater adsorption potential for OM microstructure than for the clay minerals matrix.

Keywords: maturation, methane sorption, organic matter, porosity, shales

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Authors: Debananda Mohapatra, Subramanya Badrayyana, Smrutiranjan Parida

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Carbon nano-onions (CNOs) are the spherical graphitic nanostructures composed of concentric shells of graphitic carbon can be hypothesized as the intermediate state between fullerenes and graphite. These are very important members in fullerene family also known as the multi-shelled fullerenes can be envisioned as promising supercapacitor electrode with high energy & power density as they provide easy access to ions at electrode-electrolyte interface due to their curvature. There is still very sparse report concerning on CNOs as electrode despite having an excellent electrodechemical performance record due to their unavailability and lack of convenient methods for their high yield preparation and purification. Keeping all these current pressing issues in mind, we present a facile scalable and straightforward flame synthesis method of pure and highly dispersible CNOs without contaminated by any other forms of carbon; hence, a post processing purification procedure is not necessary. To the best of our knowledge, this is the very first time; we developed an extremely simple, light weight, novel inexpensive, flexible free standing pristine CNOs electrode without using any binder element. Locally available daily used cotton wipe has been used for fabrication of such an ideal electrode by ‘dipping and drying’ process providing outstanding stretchability and mechanical flexibility with strong adhesion between CNOs and porous wipe. The specific capacitance 102 F/g, energy density 3.5 Wh/kg and power density 1224 W/kg at 20 mV/s scan rate are the highest values that ever recorded and reported so far in symmetrical two electrode cell configuration with 1M Na2SO4 electrolyte; indicating a very good synthesis conditions employed with optimum pore size in agreement with electrolyte ion size. This free standing CNOs electrode also showed an excellent cyclic performance and stability retaining 95% original capacity after 5000 charge –discharge cycles. Furthermore, this unique method not only affords binder free - freestanding electrode but also provide a general way of fabricating such multifunctional promising CNOs based nanocomposites for their potential device applications in flexible solar cells and lithium-ion batteries.

Keywords: binder-free, flame synthesis, flexible, carbon nano onion

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Authors: W. Sornlar, S. Supothina, A. Wannagon

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Lightweight geopolymer can be prepared by using some foaming agents, such as metal powders or hydrogen peroxide; however, it is difficult to control the generated cell size due to the high reactivity of the system. This study aims to investigate the influence of Sodium Lauryl Ether Sulfate (SLES) foam addition and curing temperature on the physical, mechanical, thermal, and microstructure behaviors of the lightweight kaolinite-based geopolymer. To provide porous structure, the geopolymer paste was mixed with 0-15 wt% of SLES foam before casting into the mold. Testing and characterizations were carried out after 28 days. The results showed that SLES foam generated the regular and spherical macropores, which were well distributed in the geopolymer samples. The total porosity increased as SLES foam increased, similarly as the apparent porosity and water absorption. On the other hand, the bulk density and mechanical strength decreased as SLES foam increased. Curing temperature was studied simultaneously due to it strongly affects the mechanical strength of geopolymer. In this study, rising of curing temperature from 27 to 50°C (at 75% relative humidity) improved the compressive strength of samples but deteriorated after curing at 60°C. Among them, the composition of 15 wt% SLES foam (NF15) presented the highest porosity (70.51-72.89%), the lowest density (0.68-0.73 g/cm³), and very low thermal conductivity (0.172-0.197 W/mK). It had the proper compressive strength of 4.21-4.74 MPa that can be applied for the thermal insulation.

Keywords: lightweight, kaolinite-based geopolymer, curing temperature, foaming agent, thermal conductivity

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Authors: Akila Tayeb-Benmachiche, Saber-Mustapha Zendaoui, Salah-Eddine Bouaoud, Bachir Zouchoune

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The variation of the metal coordination site in π-coordinated polycyclic aromatic hydrocarbons (PAH) corresponds to the haptotropic rearrangement or haptotropic migration in which the metal fragment MLn is considered as the moveable moiety that is shifted between two rings of polycyclic or heteropolycyclic ligands. These structural characteristics and dynamical properties give to this category of transition metal complexes a considerable interest. We have investigated the coordination and the haptotropic shifts of (CO)3Ti and CpV moieties over the phenanthridine aromatic system and according to the metal atom nature. The optimization of (CO)3Ti(PHND) and CpV(PHND), using the Amsterdam Density Functional (ADF) program, without a symmetrical restriction of geometry gives an η6 coordination mode of the C6 and C5N rings, which in turn give rise to a six low-lying deficient 16-MVE of each (CO)3Ti(PHND) and CpV(PHND) structure (three singlet and three triplet state structures for Ti complexes and three triplet and three quintet state structures for V complexes). Thus, the η6–η6 haptotropic migration of the metal fragment MLn from the terminal C6 ring to the central C5N ring has been achieved by a loss of energy. However, its η6–η6 haptotropic migration from central C5N ring to the terminal C6 rings has been accomplished by a gain of energy. These results show the capability of the phenanthridine ligand to adapt itself to the electronic demand of the metal in agreement with the nature of the metal–ligand bonding and demonstrate that this theoretical study can also be applied to large fused π-systems.

Keywords: electronic structure, bonding analysis, density functional theory, coordination chemistry haptotropic migration

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Authors: Ana-Carolina Feltrin, Daniel Hedman, Farid Akhtar

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High entropy ceramic (HEC) materials are characterized by their compositional disorder due to different metallic element atoms occupying the cation position and non-metal elements occupying the anion position. Several studies have focused on the processing and characterization of high entropy carbides and high entropy borides, as these HECs present interesting mechanical and chemical properties. A few studies have been published on HECs containing two non-metallic elements in the composition. Dual-phase high entropy (Ti₀.₂₅V₀.₂₅Zr₀.₂₅Hf₀.₂₅)BxCy ceramics with different amounts of x and y, (0.25 HfC + 0.25 ZrC + 0.25 VC + 0.25 TiB₂), (0.25 HfC + 0.25 ZrC + 0.25 VB2 + 0.25 TiB₂) and (0.25 HfC + 0.25 ZrB2 + 0.25 VB2 + 0.25 TiB₂) were sintered from boride and carbide precursor powders using SPS at 2000°C with holding time of 10 min, uniaxial pressure of 50 MPa and under Ar atmosphere. The sintered specimens formed two HEC phases: a Zr-Hf rich FCC phase and a Ti-V HCP phase, and both phases contained all the metallic elements from 5-50 at%. Phase quantification analysis of XRD data revealed that the molar amount of hexagonal phase increased with increased mole fraction of borides in the starting powders, whereas cubic FCC phase increased with increased carbide in the starting powders. SPS consolidated (Ti₀.₂₅V₀.₂₅Zr₀.₂₅Hf₀.₂₅)BC0.5 and (Ti₀.₂₅V₀.₂₅Zr₀.₂₅Hf₀.₂₅)B1.5C0.25 had respectively 94.74% and 88.56% relative density. (Ti₀.₂₅V₀.₂₅Zr₀.₂₅Hf₀.₂₅)B0.5C0.75 presented the highest relative density of 95.99%, with Vickers hardness of 26.58±1.2 GPa for the borides phase and 18.29±0.8 GPa for the carbides phase, which exceeded the reported hardness values reported in the literature for high entropy ceramics. The SPS sintered specimens containing lower boron and higher carbon presented superior properties even though the metallic composition in each phase was similar to other compositions investigated. Dual-phase high entropy (Ti₀.₂₅V₀.₂₅Zr₀.₂₅H₀.₂₅)BxCy ceramics were successfully fabricated in a boride-carbide solid solution and the amount of boron and carbon was shown to influence the phase fraction, hardness of phases, and density of the consolidated HECs. The microstructure and phase formation was highly dependent on the amount of non-metallic elements in the composition and not only the molar ratio between metals when producing high entropy ceramics with more than one anion in the sublattice. These findings show the importance of further studies about the optimization of the ratio between C and B for further improvements in the properties of dual-phase high entropy ceramics.

Keywords: high-entropy ceramics, borides, carbides, dual-phase

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Authors: Esra Yel, Tabriz Aslanov, Merve Sogancioglu, Suheyla Kocaman, Gulnare Ahmetli

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The disposal of waste plastics has become a major worldwide environmental problem. Pyrolysis of waste plastics is one of the routes to waste minimization and recycling that has been gaining interest. In pyrolysis, the pyrolysed material is separated into gas, liquid (both are fuel) and solid (char) products. All fractions have utilities and economical value depending upon their characteristics. The first objective of this study is to determine the co-pyrolysis product fractions of waste HDPE- (high density polyethylene) and LDPE (low density polyethylene)-olive pomace (OP) and to determine the qualities of the solid product char. Chars obtained at 700 °C pyrolysis were used in biocomposite preparation as additive. As the second objective, the effects of char on biocomposite quality were investigated. Pyrolysis runs were performed at temperature 700 °C with heating rates of 5 °C/min. Biocomposites were prepared by mixing of chars with bisphenol-F type epoxy resin in various wt%. Biocomposite properties were determined by measuring electrical conductivity, surface hardness, Young’s modulus and tensile strength of the composites. The best electrical conductivity results were obtained with HDPE-OP char. For HDPE-OP char and LDPE-OP char, compared to neat epoxy, the tensile strength values of the composites increased by 102% and 78%, respectively, at 10% char dose. The hardness measurements showed similar results to the tensile tests, since there is a correlation between the hardness and the tensile strength.

Keywords: biocomposite, char, olive pomace, pyrolysis

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Authors: M. L. Gaol, I. W. Mudita

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Indonesia is well known as a country covered by lush tropical rain forests, but in fact, the northeastern part of the country, within the areas geologically known as Lesser Sunda, the dominant vegetation is tropical savanna. Lesser Sunda is a chain of islands located closer to Australia than to islands in the other parts of the country. Among those of islands in the chain which is closes to Australia, and thereby most strongly affected by the hot and dry Australian climate, is the island of Timor, the western part of which belongs to Indonesia and the eastern part is a sovereign state East Timor. Regardless of being the most dominant vegetation cover, tropical savanna in West Timor, especially its understory, is rarely investigated. This research was therefore carried out to investigate the structure, composition and diversity of the understory of this tropical savanna as the basis for looking at the possibility of introducing other spesieis for various purposes. For this research, 14 terrestrial communities representing major types of the existing savannas in West Timor was selected with aid of the most recently available satellite imagery. At each community, one stand of the size of 50 m x 50 m most likely representing the community was as the site of observation for the type of savanna under investigation. At each of the 14 communities, 20 plots of 1 m x 1 m in size was placed at random to identify understory species and to count the total number of individuals and to estimate the cover of each species. Based on such counts and estimation, the important value of each species was later calculated. The results of this research indicated that the understory of savanna in West Timor consisted of 73 understory species. Of this number of species, 18 species are grasses and 55 are non-grasses. Although lower than non-grass species, grass species indeed dominated the savanna as indicated by their number of individuals (65.33 vs 34.67%), species cover (57.80 vs 42.20%), and important value (123.15 vs 76.85). Of the 14 communities, the lowest density of grass was 13.50/m2 and the highest was 417.50/m2. Of 18 grass species found, all were commonly found as agricultural weeds, whereas of 55 non-grass, 10 species were commonly found as agricultural weeds, environmental weeds, or invasive species. In terms of better managing the savanna in the region, these findings provided the basis for planning a more integrated approach in managing such agricultural and environmental weeds as well as invasive species by considering the structure, composition, and species diversity of the understory species existing in each site. These findings also provided the basis for better understanding the flora of the region as a whole and for developing a flora database of West Timor in future.

Keywords: tropical savanna, understory species, integrated management, weedy and invasive species

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Authors: Cenk Aksit, Suleyman Kodal, Yusuf Ersoy Yildirim

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Normalized Difference Vegetation Index (NDVI) is a widely used index in the world that provides reference information, such as the health status of the plant, and the density of the vegetation in a certain area, by making use of the electromagnetic radiation reflected from the plant surface. On the other hand, the chlorophyll index provides reference information about the chlorophyll density in the plant by making use of electromagnetic reflections at certain wavelengths. Chlorophyll concentration is higher in healthy plants and decreases as plant health decreases. This study, it was aimed to determine the changes in Normalize Difference Vegetation Index (NDVI) and Normalize Difference Chlorophyll (NDCI) of silage corn irrigated with subsurface drip irrigation systems under different irrigation levels. In 5 days irrigation interval, the daily potential plant water consumption values were collected, and the calculated amount was applied to the full irrigation and 3 irrigation water levels as irrigation water. The changes in NDVI and NDCI of silage corn irrigated with subsurface drip irrigation systems under different irrigation levels were determined. NDVI values have changed according to the amount of irrigation water applied, and the highest NDVI value has been reached in the subject where the most water is applied. Likewise, it was observed that the chlorophyll value decreased in direct proportion to the amount of irrigation water as the plant approached the harvest.

Keywords: NDVI, NDCI, sub-surface drip irrigation, silage corn, deficit irrigation

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Authors: Nouria Bouchikhi, Soufiane Bedjaoui, C. Tewfik Bouchaour, Lamia Alachaher Bedjaoui, Ulrich Maschke

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Swelling properties and phase diagrams of binary systems composed of liquid crystalline networks and a low molecular mass liquid crystal (LMWLC) have been investigated. The networks were prepared by ultraviolet (UV) irradiation of reactive mixtures including a monomer, a cross-linking agent and a photo-initiator. These networks were prepared using two cross-linking agents: 1,6 hexanedioldiacrylate (HDDA) and a mesogenic acrylic acid 6-(4’-(6-acryloyloxy-hexyloxy) biphenyl-4-yl oxy) hexyl ester (AHBH). The obtained dry networks were characterized by differential scanning calorimetry, and immersed in an excess of a LMWLC solvent 4-cyano-4’-pentylbiphenyl (5CB), forming polymer gels. A detailed study by polarized optical microscopy allowed to determine the swelling degree of the gels and to follow the phase behavior of the solvent inside the polymer matrix in a wide range of temperature. It has been found that the gels undergo a sharp decrease of their swelling degree in response to an infinitesimal change of temperature. This finding adds new and interesting aspects on the actuators applications. We have subsequently explored the effect of different parameters on volume phase transition of these liquid crystalline materials. Such as the cross-linking density (CD), a nature of cross-linking agent and the photo initiator concentration.

Keywords: cross-linking density, liquid crystalline elastomers, phase diagrams, swelling

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Authors: N. G. Margiani, I. G. Kvartskhava, G. A. Mumladze, Z. A. Adamia

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Chemical doping with different elements and compounds at various amounts represents the most suitable approach to improve the superconducting properties of bismuth-based superconductors for technological applications. In this paper, the influence of partial substitution of Sr(BO₂)₂ for SrO on the phase formation kinetics and transport properties of (Bi,Pb)-2223 HTS has been studied for the first time. Samples with nominal composition Bi_1.7Pb_0.3Sr_2-xCa₂Cu₃O_y[Sr(BO₂)₂]_x, x=0, 0.0375, 0.075, 0.15, 0.25, were prepared by the standard solid state processing. The appropriate mixtures were calcined at 845 ^oC for 40 h. The resulting materials were pressed into pellets and annealed at 837 ^oC for 30 h in air. Superconducting properties of undoped (reference) and Sr(BO₂)₂-doped (Bi,Pb)-2223 compounds were investigated through X-ray diffraction (XRD), resistivity (ρ) and transport critical current density (J_c) measurements. The surface morphology changes in the prepared samples were examined by scanning electron microscope (SEM). XRD and J_c studies have shown that the low level Sr(BO₂)₂ doping (x=0.0375-0.075) to the Sr-site promotes the formation of high-T_c phase and leads to the enhancement of current carrying capacity in (Bi,Pb)-2223 HTS. The doped sample with x=0.0375 has the best performance compared to other prepared samples. The estimated volume fraction of (Bi,Pb)-2223 phase increases from ~25 % for reference specimen to ~70 % for x=0.0375. Moreover, strong increase in the self-field J_c value was observed for this dopant amount (J_c=340 A/cm²), compared to an undoped sample (J_c=110 A/cm²). Pronounced enhancement of superconducting properties of (Bi,Pb)-2223 superconductor can be attributed to the acceleration of high-T_c phase formation as well as the improvement of inter-grain connectivity by small amounts of Sr(BO₂)₂ dopant.

Keywords: bismuth-based superconductor, critical current density, phase formation, Sr(BO₂)₂ doping

Procedia PDF Downloads 242

Authors: Wantanee Polviset, N. Prakobsaeng, N. Wetchakama, C. Yuangklang

Abstract:

The aim of this study was to evaluate the effect of soybean oil, palm oil and sunflower oil supplementations in total mixed ration on voluntary feed intake, dry matter (DM) digestibility and blood metabolize in crossbred Thai native x American Brahman Cattle. Three Thai native x American Brahman cattle, one-year-old with liveweight of 116±22.59 kg, were randomly assigned according to a 3 x 3 latin square design. Each period of feeding lasted for 21 days to receive three dietary treatments were soybean oil, palm oil and sunflower oil supplementation at 5%. During the experimental periods, all cattle were fed a diet with total mixed ration containing roughage to concentrate ratio of 40:60 and rice straw was used as a roughage source. Based on the present study, the results revealed that voluntary feed intake (kgDM/head/day) and %BW DM intake were not affected (P>0.05), whereas percentage of dry matter digestibility was greater with the soybean oil supplementation (P<0.01). It was also found that blood glucose, blood urea nitrogen, cholesterol, triglyceride, high density lipoprotein and low density lipoprotein in plasma were similar among treatments. Based on this study, supplementing 5% soybean oil in total mixed ration (TMR) diets was suitable in beef cattle without any effect dry matter digestibility and blood metabolites.

Keywords: plant oils, feed intake, blood metabolize, crossbred Thai native x Brahman cattle

Procedia PDF Downloads 319

Authors: Meriem Taleb, Ghania Tail, Fatma Zohra Kara, Brahim Djedouani, T. Moussa

Abstract:

Forensic entomology is the use of insects and their arthropod relatives as silent witnesses to aid legal investigations by interpreting information concerning a death. The main purpose of forensic entomology is to establish the postmortem interval or PMI Postmortem interval is a matter of crucial importance in the investigations of homicide and other untimely deaths when the body found is after three days. Forensic entomology has grown immensely as a discipline in the past thirty years. In Algeria, forensic entomology was introduced in 2010 by the National Institute for Criminalistics and Criminology of the National Gendarmerie (NICC). However, all the work that has been done so far in this growing field in Algeria has been unknown at both the national and international levels. In this context, the aim of this paper is to describe the state of forensic entomology in Algeria. The Laboratory of Entomology of the NICC is the only one of its kind in Algeria. It started its activities in 2010, consisting of two specialists. The main missions of the laboratory are estimation of the PMI by the analysis of entomological evidence, and determination if the body was moved. Currently, the laboratory is performing different tasks such as the expert work required by investigators to estimate the PMI using the insects. The estimation is performed by the accumulated degree days method (ADD) in most of the cases except for those where the cadaver is in dry decay. To assure the quality of the entomological evidence, crime scene personnel are trained by the laboratory of Entomology of the NICC. Recently, undergraduate and graduate students have been studying carrion ecology and insect activity in different geographic locations of Algeria using rabbits and wild boar cadavers as animal models. The Laboratory of Entomology of the NICC has also been involved in some of these research projects. Entomotoxicology experiments are also conducted with the collaboration of the Toxicology Department of the NICC. By dint of hard work that has been performed by the Laboratory of Entomology of the NICC, official bodies have been adopting more and more the use of entomological evidence in criminal investigations in Algeria, which is commendable. It is important, therefore, that steps are taken to fill in the gaps in the knowledge necessary for entomological evidence to have a useful future in criminal investigations in Algeria.

Keywords: forensic entomology, corpse, insects, postmortem interval, expertise, Algeria

Procedia PDF Downloads 405

Authors: Tamal Sur, Tapas Acharya

Abstract:

Identifying the water resource in hard crystalline rock terrain has been a huge challenge over the decades as it is considered a poor groundwater province area. Over the years, usage of satellite imagery for the delineation of groundwater potential zone in sheared hard rock terrain has been occasionally successful. In numerous circumstances, it has been observed that groundwater potential zone delineated by satellite imagery study has failed to yield satisfactory result on its own. The present study discusses the fact that zones having a high concentration of lineaments oblique to the general trend of shear fabric could be good groundwater potential zones within a shear zone in crystalline fractured rock aquifer system. Due to this fact, the density of lineaments and the number of intersecting lineaments increases over that particular region, making it a suitable locale for good groundwater recharge, which is mostly composed of Precambrian metamorphic rocks i.e., quartzite, granite gneisses, porphyroclastic granite-gneiss, quartzo-feldspathic-granite-gneiss, mylonitic granites, quartz-biotite-granite gneiss and some phyllites of Purulia district of West Bengal, NE India. This study aims to construct an attempt to demonstrate the relationship of the high amount of lineament accumulation and their intersection with high groundwater fluctuation zones, i.e., good groundwater potential zones. On the basis of that, an effort has been made to characterize the shear zones with respect to their groundwater potentiality. Satellite imagery data (IRS-P6 LISS IV standard FCC image) analysis reveals the bifurcating nature of North Purulia shear zone (NPSZ) and South Purulia shear zone (SPSZ) over the study area. Careful analysis of lineament rose diagrams, lineament density map, lineament intersection density map, and frequency diagrams for water table depths with an emphasis on high water table fluctuations exhibit the fact that different structural features existing over North and South Purulia shear zones can affect the nature of hydraulic potential of that region.

Keywords: crystalline hard rock terrain, groundwater recharge, hydrogeology, lineaments, shear zone, water table fluctuation

Procedia PDF Downloads 86

Authors: Varun K, Pramod B. Balareddy

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Estimation of wind forces plays a significant role in the in the design of large antenna parabolic reflectors. Reflector surface accuracies are very sensitive to the gain of the antenna system at higher frequencies. Hence accurate estimation of wind forces becomes important, which is primary input for design and analysis of the reflector system. In the present work, numerical simulation of wind flow using Computational Fluid Dynamics (CFD) software is used to investigate the external pressure coefficients. An extensive comparative study has been made between the CFD results and the published wind tunnel data for different wind angle of attacks (α) acting over concave to convex surfaces respectively. Flow simulations using CFD are carried out to estimate the coefficients of Drag, Lift and Moment for the parabolic reflector. Coefficients of pressures (Cp) over the front and the rear face of the reflector are extracted over surface of the reflector to study the net pressure variations. These resultant pressure variations are compared with the published wind tunnel data for different angle of attacks. It was observed from the CFD simulations, both convex and concave face of reflector system experience a band of pressure variations for the positive and negative angle of attacks respectively. In the published wind tunnel data, Pressure variations over convex surfaces are assumed to be uniform and vice versa. Chordwise and spanwise pressure variations were calculated and compared with the published experimental data. In the present work, it was observed that the maximum pressure coefficients for α ranging from +30° to -90° and α=+90° was lower. For α ranging from +45° to +75°, maximum pressure coefficients were higher as compared to wind tunnel data. This variation is due to non-uniform pressure distribution observed over front and back faces of reflector. Variations in Cd, Cl and Cm over α=+90° to α=-90° was in close resemblance with the experimental data.

Keywords: angle of attack, drag coefficient, lift coefficient, pressure coefficient

Procedia PDF Downloads 257

Authors: Meixia Zhang, Chengjun Ji, Wenxuan Han

Abstract:

Many wood traits are important functional attributes for tree species, connected with resource competition among species, community dynamics, and ecosystem functions. Large variations in these traits exist among taxonomic categories, but variation in these traits between gymnosperms and angiosperms is still poorly documented. This paper explores the systematic differences in 12 traits between the two tree categories and the potential effects of environmental factors and life form. Based on a database of wood traits for major gymnosperm and angiosperm tree species across China, the values of 12 wood traits and their driving factors in gymnosperms vs. angiosperms were compared. The results are summarized below: i) Means of wood traits were all significantly lower in gymnosperms than in angiosperms. ii) Air-dried density (ADD) and tangential shrinkage coefficient (TSC) reflect the basic information of wood traits for gymnosperms, while ADD and radial shrinkage coefficient (RSC) represent those for angiosperms, providing higher explanation power when used as the evaluation index of wood traits. iii) For both gymnosperm and angiosperm species, life form exhibits the largest explanation rate for large-scale spatial patterns of ADD, TSC (RSC), climatic factors the next, and edaphic factors have the least effect, suggesting that life form is the dominant factor controlling spatial patterns of wood traits. Variations in the magnitude and key traits between gymnosperms and angiosperms and the same dominant factors might indicate the evolutionary divergence and convergence in key functional traits among woody plants.

Keywords: allometry, functional traits, phylogeny, shrinkage coefficient, wood density

Procedia PDF Downloads 273

Authors: Tamal Sur, Tapas Acharya

Abstract:

Identifying the water resource in hard crystalline rock terrain has been a huge challenge over the decades as it is considered a poor groundwater province area. Over the years, usage of satellite imagery for the delineation of groundwater potential zone in sheared hard rock terrain has been occasionally successful. In numerous circumstances, it has been observed that groundwater potential zone delineated by satellite imagery study has failed to yield satisfactory result on its own. The present study discusses the fact that zones having high concentration of lineaments oblique to the general trend of shear fabric could be good groundwater potential zones within a shear zone in crystalline fractured rock aquifer system. Due to this fact, the density of lineaments and the number of intersecting lineaments increases over that particular region, making it a suitable locale for good groundwater recharge, which is mostly composed of Precambrian metamorphic rocks i.e., quartzite, granite gneisses, porphyroclastic granite-gneiss, quartzo-feldspathic-granite-gneiss, mylonitic granites, quartz-biotite-granite gneiss and some phyllites of Purulia district of West Bengal, NE India. This study aims to construct an attempt to demonstrate the relationship of high amount of lineament accumulation and their intersection with high groundwater fluctuation zones i.e., good groundwater potential zones. On the basis of that, an effort has been made to characterize the shear zones with respect to their groundwater potentiality. Satellite imagery data (IRS-P6 LISS IV standard FCC image) analysis reveals the bifurcating nature of North Purulia shear zone (NPSZ) and South Purulia shear zone (SPSZ) over the study area. Careful analysis of lineament rose diagrams, lineament density map, lineament intersection density map, and frequency diagrams for water table depths with an emphasis on high water table fluctuations exhibit the fact that different structural features existing over North and South Purulia shear zones can affect the nature of hydraulic potential of that region.

Keywords: crystalline hard rock terrain, groundwater recharge, hydrogeology, lineaments, shear zone, water table fluctuation

Procedia PDF Downloads 76

Authors: Mohammad Shabani

Abstract:

The physical activities depending on the nature of the mechanical stresses they induce on bone sometimes have brought about different results. The purpose of this study was to compare bone mineral density (BMD) of the lumbar spine between the high-level cyclists and sedentary. Materials and Methods: In the present study, 73 cyclists senior (age: 25.81 ± 4.35 years; height: 179.66 ± 6.31 cm; weight: 71.55 ± 6.31 kg) and 32 sedentary subjects (age: 28.28 ± 4.52 years; height: 176.56 ± 6.2 cm; weight: 74.47 ± 8.35 kg) participated voluntarily. All cyclists belonged to the different teams from the International Cycling Union and they trained competitively for 10 years. BMD of the lumbar spine of the subjects was measured using DXA X-ray (Lunar). Descriptive statistics calculations were performed using computer software data processing (Statview 5, SAS Institute Inc. USA). The comparison of two independent distributions (BMD high level cyclists and sedentary) was made by the Student T Test standard. Probability 0.05 (p≤0 / 05) was adopted as significance. Results: The result of this study showed that the BMD values of the lumbar spine of sedentary subjects were significantly higher for all measured segments. Conclusion and Discussion: Cycling is firstly a common sport and on the other hand endurance sport. It is now accepted that weight bearing exercises have an osteogenic effect compared to non-weight bearing exercises. Thus, endurance sports such as cycling, compared to the activities imposing intense force in short time, seem not to really be osteogenic. Therefore, it can be concluded that cycling provides low stimulates osteogenic because of specific biomechanical forces of the sport and its lack of impact.

Keywords: BMD, lumbar spine, high level cyclist, cycling

Procedia PDF Downloads 267

Authors: Lu-Yin Lin

Abstract:

The morphology of electroactive material is highly related to energy storage ability. Structure-directing agent (SDA) can design electroactive materials with favorable surface properties. Zeolitic imidazolate framework 67 (ZIF67) is one of the potential electroactive materials for energy storage devices. The SDA concept is less applied to designing ZIF67 derivatives in previous studies. An in-situ technique with ammonium fluoride (NH₄F) as SDA is proposed to produce a ZIF67 derivative with highly improved energy storage ability. Attracted by the effective in-situ technique, the NH₄F, ammonium bifluoride (NH₄HF₂), and ammonium tetrafluoroborate (NH₄BF₄) are first used as SDA to synthesize ZIF67 derivatives in one-step solution process as electroactive material of energy storage devices. The mechanisms of forming ZIF67 derivatives synthesized with different SDAs are discussed to explain the SDA effects on physical and electrochemical properties. The largest specific capacitance (CF) of 1527.0 Fg-¹ and the capacity of 296.9 mAhg-¹ are obtained for the ZIF67 derivative prepared using NH₄BF₄ as SDA. The energy storage device composed of the optimal ZIF67 derivative and carbon electrodes presents a maximum energy density of 15.1 Whkg-¹ at the power density of 857 Wkg-¹. The CF retention of 90% and Coulombic efficiency larger than 98% are also obtained after 5000 cycles.

Keywords: ammonium bifluoride, ammonium tetrafluoroborate, energy storage device, one-step solution process, structure-directing agent, zeolitic imidazolate framework 67

Procedia PDF Downloads 78

Authors: Chun-Wei Yeh, Santhanamoorthi Nachimuthu, Jyh-Chiang Jiang

Abstract:

Reducing greenhouse gases or converting them into fuels and chemicals with added value is vital for the environment. Given the enhanced techniques for hydrocarbon extraction in this context, the catalytic conversion of methane to methanol is particularly intriguing for future applications as vehicle fuels and/or bulk chemicals. Metal-organic frameworks (MOFs) have received much attention recently for the oxidation of methane to methanol. In addition, biomimetic material, particulate methane monooxygenase (pMMO), has been reported to convert methane using copper oxide clusters as active sites. Inspired by these, in this study, we considered the well-known MIL-53(Al) MOF as support for copper oxide clusters (Cu2Ox, Cu3Ox) to investigate their reactivity towards methane oxidation using Density Functional Theory (DFT) calculations. The copper oxide clusters (Cu2O2, Cu3O2) are modeled by oxidizing copper clusters (Cu2, Cu3) with two oxidizers, O2 and N2O. The initial C-H bond activation barriers on Cu2O2/MIL-53(Al) and Cu3O2/MIL-53(Al) catalysts are 0.70 eV and 0.64 eV, respectively, and are the rate-determining steps in the overall methane conversion to methanol reactions. The desorption energy of the methanol over the Cu2O/MIL-53(Al) and Cu3O/MIL-53(Al) is 0.71eV and 0.75 eV, respectively. Furthermore, to explore the prospect of catalyst reusability, we considered the different oxidants and proposed the different reaction pathways for completing the reaction cycle and regenerating the active copper oxide clusters. To know the reason for the difference between bi-copper and tri-cooper systems, we also did an electronic analysis. Finally, we calculate the Microkinetic Simulation. The result shows that the reaction can happen at room temperature.

Keywords: DFT study, copper oxide cluster, MOFs, methane conversion

Procedia PDF Downloads 77

Authors: Marija Milašinović-Šeremešić, Valentina Semenčenko, Milica Radosavljević, Dušanka Terzić, Ljiljana Mojović, Ljubica Dokić

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Maize (Zea mays L.) is one of the most important cereal crops, and as such, one of the most significant naturally renewable carbohydrate raw materials for the production of energy and multitude of different products. The main goal of the present study was to investigate a suitability of selected maize hybrids of different genetic background produced in Maize Research Institute ‘Zemun Polje’, Belgrade, Serbia, for starch, bioethanol and animal feed production. All the hybrids are commercial and their detailed characterization is important for the expansion of their different uses. The starches were isolated by using a 100-g laboratory maize wet-milling procedure. Hydrolysis experiments were done in two steps (liquefaction with Termamyl SC, and saccharification with SAN Extra L). Starch hydrolysates obtained by the two-step hydrolysis of the corn flour starch were subjected to fermentation by S. cerevisiae var. ellipsoideus under semi-anaerobic conditions. The digestibility based on enzymatic solubility was performed by the Aufréré method. All investigated ZP maize hybrids had very different physical characteristics and chemical composition which could allow various possibilities of their use. The amount of hard (vitreous) and soft (floury) endosperm in kernel is considered one of the most important parameters that can influence the starch and bioethanol yields. Hybrids with a lower test weight and density and a greater proportion of soft endosperm fraction had a higher yield, recovery and purity of starch. Among the chemical composition parameters only starch content significantly affected the starch yield. Starch yields of studied maize hybrids ranged from 58.8% in ZP 633 to 69.0% in ZP 808. The lowest bioethanol yield of 7.25% w/w was obtained for hybrid ZP 611k and the highest by hybrid ZP 434 (8.96% w/w). A very significant correlation was determined between kernel starch content and the bioethanol yield, as well as volumetric productivity (48h) (r=0.66). Obtained results showed that the NDF, ADF and ADL contents in the whole maize plant of the observed ZP maize hybrids varied from 40.0% to 60.1%, 18.6% to 32.1%, and 1.4% to 3.1%, respectively. The difference in the digestibility of the dry matter of the whole plant among hybrids (ZP 735 and ZP 560) amounted to 18.1%. Moreover, the differences in the contents of the lignocelluloses fraction affected the differences in dry matter digestibility. From the results it can be concluded that genetic background of the selected maize hybrids plays an important part in estimation of the technological value of maize hybrids for various purposes. Obtained results are of an exceptional importance for the breeding programs and selection of potentially most suitable maize hybrids for starch, bioethanol and animal feed production.

Keywords: bioethanol, biomass quality, maize, starch

Procedia PDF Downloads 221

Authors: Jie Ding, Yingying Pan, Shammy Raj, Lindy Schaffrick, Jolene Wong, Antoinette Nguyen, Sharada Manchikanti, Larry Unsworth, Peter Kwan, Edward E. Tredget

Abstract:

Background: Exosomes (EXOs) have been considered a new target that is thought to be involved in and treat wound healing. More research is needed to fully understand the EXO characteristics and mechanisms of EXO-mediated wound healing, especially wound healing after burn injury. Methods: Total EXOs were isolated from 85 serum samples of 29 burn patients and 13 healthy individuals. We characterized the EXOs for morphology and density, serum concentration, protein level, marker expression, size distribution, and cytokine content. After confirmation of EXO uptake by dermal fibroblasts, we also explored functional regulation of primary human normal skin and hypertrophic scar fibroblast cell lines by the EXOs in vitro, including cell proliferation and apoptosis. Results: EXOs dynamically changed their morphology, density, size, and cytokine level during wound healing in burn patients, which were correlated with burn severity and the stages of wound healing. EXOs from both burn patients and healthy individuals stimulated dermal fibroblast proliferation and apoptosis. Conclusion: EXO features may be important signals that influence wound healing after burn injury; however, to understand the mechanisms by which EXOs regulated the fibroblasts in healing wounds, further studies will be required in the future.

Keywords: exosome, burn, wound healing, hypertrophic scarring, cytokines

Procedia PDF Downloads 80

Authors: Nuha Alamro

Abstract:

Besides achieving of weight loss, Bariatric surgery (BS) shown metabolic improvement including reduction of cardiovascular disease, insulin resistance and diabetes. This study aimed to measure BS effects on Framingham Risk Score (FRS) and metabolic syndrome (MetS) among patients who underwent BS. Additionally, to determine the effect of BS on TSH among euthyroid obese patients. A Retrospective follow-up study was conducted in King Abdullah Medical City. A total of 160 participants who underwent BS and completed one year of follow ups. Medical history, biochemical, anthropometric, and hormonal parameters were evaluated at baseline and 3-12 months after BS. International Diabetes Federation (IDF) criteria were used to diagnose MetS pre and postoperative. The mean age of participants was 41.9 ± 10.6 with Body Mass Index (BMI) of 48.8 ± 7.3. After 3 months, Systolic, Diastolic blood pressure (SBP, DBP), glycated haemoglobin (HBA1C), Low-density lipoprotein (LDL), cholesterol, triglycerides and Thyroid stimulating hormone (TSH) were significantly decrease (P < 0.001). Significant decrease was seen in Mets, BMI, FRS, SBP, DBP, HBA1C, LDL, triglycerides, cholesterol, liver enzyme, with significant increase in high-density lipoprotein (HDL) level 12 months post-op (P < 0.001). After 1 year, the prevalence of MetS, DM, HTN, FRS were significantly decrease from 72.5%, 43.1%, 78.1%, 11.4 to 16.3%, 9.4%, 22.5% and 5.4, respectively. Besides achieving substantial weight loss, MetS resolution was linked to improvement in cardiovascular risk profile.

Keywords: bariatric surgery, cardiovascular disease, metabolic syndrome, thyroid stimulating hormone

Procedia PDF Downloads 100

Authors: S. K. Fasogbon, O. E. Oguegbu

Abstract:

Pasteurization is one of the most important steps in the preservation of beer products, which improves its shelf life by inactivating almost all the spoilage organisms present in it. However, there is no gain saying the fact that it is always difficult to determine the slowest heating zone, the temperature profile and pasteurization units inside bottled beer during pasteurization, hence there had been significant experimental and ANSYS fluent approaches on the problem. This work now developed Computational fluid dynamics model using COMSOL Multiphysics. The model was simulated to determine the slowest heating zone, temperature profile and pasteurization units inside the bottled beer during the pasteurization process. The results of the simulation were compared with the existing data in the literature. The results showed that, the location and size of the slowest heating zone is dependent on the time-temperature combination of each zone. The results also showed that the temperature profile of the bottled beer was found to be affected by the natural convection resulting from variation in density during pasteurization process and that the pasteurization unit increases with time subject to the temperature reached by the beer. Although the results of this work agreed with literatures in the aspects of slowest heating zone and temperature profiles, the results of pasteurization unit however did not agree. It was suspected that this must have been greatly affected by the bottle geometry, specific heat capacity and density of the beer in question. The work concludes that for effective pasteurization to be achieved, there is a need to optimize the spray water temperature and the time spent by the bottled product in each of the pasteurization zones.

Keywords: modeling, heat transfer, temperature profile, pasteurization process, bottled beer

Procedia PDF Downloads 202