Search results for: plant structure
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 11021

Search results for: plant structure

8501 Experimental Performance of Vertical Diffusion Stills Utilizing Folded Sheets for Water Desalination

Authors: M. Mortada, A. Seleem, M. El-Morsi, M. Younan

Abstract:

The present study introduces the folding technology to be utilized for the first time in vertical diffusion stills. This work represents a model of the distillation process by utilizing chevron pattern of folded structure. An experimental setup has been constructed, to investigate the performance of the folded sheets in the vertical effect diffusion still for a specific range of operating conditions. An experimental comparison between the folded type and the flat type sheets has been carried out. The folded pattern showed a higher performance and there is an increase in the condensate to feed ratio that ranges from 20-30 % through the operating hot plate temperature that ranges through 60-90°C. In addition, a parametric analysis of the system using Design of Experiments statistical technique, has been developed using the experimental results to determine the effect of operating conditions on the system's performance and the best operating conditions of the system has been evaluated.

Keywords: chevron pattern, fold structure, solar distillation, vertical diffusion still

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8500 Stress-Controlled Senescence and Development in Arabidopsis thaliana by Root Associated Factor (RAF), a NAC Transcription Regulator

Authors: Iman Kamranfar, Gang-Ping Xue, Salma Balazadeh, Bernd Mueller-Roeber

Abstract:

Adverse environmental conditions such as salinity stress, high temperature and drought limit plant growth and typically lead to precocious tissue degeneration and leaf senescence, a process by which nutrients from photosynthetic organs are recycled for the formation of flowers and seeds to secure reaching the next generation under such harmful conditions. In addition, abiotic stress affects developmental patterns that help the plant to withstand unfavourable environmental conditions. We discovered an NAC (for NAM, ATAF1, 2, and CUC2) transcription factor (TF), called RAF in the following, which plays a central role in abiotic drought stress-triggered senescence and the control of developmental adaptations to stressful environments. RAF is an ABA-responsive TF; RAF overexpressors are hypersensitive to abscisic acid (ABA) and exhibit precocious senescence while knock-out mutants show delayed senescence. To explore the RAF gene regulatory network (GRN), we determined its preferred DNA binding sites by binding site selection assay (BSSA) and performed microarray-based expression profiling using inducible RAF overexpression lines and chromatin immunoprecipitation (ChIP)-PCR. Our studies identified several direct target genes, including those encoding for catabolic enzymes acting during stress-induced senescence. Furthermore, we identified various genes controlling drought stress-related developmental changes. Based on our results, we conclude that RAF functions as a central transcriptional regulator that coordinates developmental programs with stress-related inputs from the environment. To explore the potential agricultural applications of our findings, we are currently extending our studies towards crop species.

Keywords: abiotic stress, Arabidopsis, development, transcription factor

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8499 Hot Spot Stress Analysis and Parametric Study on Rib-To-Deck Welded Connections in Orthotropic Steel Bridge Decks

Authors: Dibu Dave Mbako, Bin Cheng

Abstract:

This paper study the stress variation of the welded joints in the rib-to-deck connection structure, the influence stress of the deck plate and u-rib thickness at different positions. A Finite-element model of orthotropic steel deck structure using solid element and shell element was established in ABAQUS. Under a single wheel load, the static response was analyzed to understand the structural behaviors and examine stress distribution. A parametric study showed that the geometric parameters have a significant effect on the hot spot stress at the weld toe, but has little impact on the stress concentration factor. The increase of the thickness of the deck plate will lead to the decrease of the hot spot stress at the weld toe and the maximum deflection of the deck plate. The surface stresses of the deck plate are significantly larger than those of the rib near the joint in the 80% weld penetration into the u-rib.

Keywords: orthotropic steel bridge deck, rib-to-deck connection, hot spot stress, finite element method, stress distribution

Procedia PDF Downloads 223
8498 Association Between Grandchild Caring With Different Household Structures and Depression at Later Life: A Cross-Sectional Study in India

Authors: Papai Barman, Harihar Sahoo

Abstract:

With increasing life expectancy, urbanization, and adult out migration, elder people live without adult child and most of time responsible for grandchild caring while the care is needed for them. On this line, the current study examined the association between grandchild caring (GCC) with different household structures and depression among elderly (60+) grandparents (GP) living in India using Longitudinal Aging Study in India (LASI), 2017-18. HH structure was defined as the skipped-generation household (SGH) where GP and GC lived together without middle generation and the multi-generation household (MGH) where more than two generations lived together. GCC was defined by two categories, compulsive and non-compulsive caring. CES-D depression scale was utilized to measure GP’s mental health. Socio-economic characteristics, chronic diseases, and health behavior were controlled to get the effect of HH structure and GCC considered key explanatory variables. Bivariate analyses showed that the prevalence of elderly lived in SGH in India (2.5%). Prevalence of compulsive caring was found 16.3% in MGH and 51.1% in SGH. Prevalence of depressions was found nearly 37.1 and 49.5% among the GPs responsible for GCC in MGH and SGH, respectively. Using Biprobit and margins results, GPs lived in SGH were 0.40 times (dy/dx=0.40, p<0.001) more likely to report depression than GPs lived in MGH, given the condition on compulsive caring. Ensuring SDG goal-3, health aging, and giving more social security to the elder people responsible for caring while they are needed care at later life, the current study may improve the existing knowledge and help policy makers to make an intervention on this most vulnerable people, especially for the elderly people living in SGH and responsible for caring.

Keywords: household structure, grandchild caring, skipped-generation household, multi-generation household, depression, mental health, India

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8497 Impact of Bio Preparations on Agro-Chemical Indexes and Fruit Mineral Composition of Mandarin (Citrus Reticulata) Orchard

Authors: Nunu Nakashidze, Shota Lominadze, Darejan Jashi

Abstract:

Citrus culture used to be one of the leading fields of sub-tropical agriculture in Georgia and especially in Adjara region, but the citrus production has been significantly decreased in recent years due to deterioration of quality index of fruit and reduction of sale markets. The fact severely affected both the economy of Republic and population. Intensive technologies of citrus fruit production are widely implemented in the world practices, which include the following: variety of species, consumption of fertilizers and chemicals, proper use of fruit production and etc. However working on technologies which ensure getting of high quality and plentiful product is very much important if taking into consideration modern, global ecological problems. Using of bio-preparations for plant nourishment is considered as one of the activities. The present work discusses liquid organic fertilizer 'Biorag' produced in Georgia and influence of its growth stimulation (Gakhokidze N1, N2, N3) on agrochemical index of soils and mineral composition of fruit of Citrus Unshiu orchards cultivated in the sub-tropical zone of Black Sea in Adjara region. It was ascertained that liquid organic fertilizers used in the orchard of citrus 'Unshiu' and influence of growth stimulators on the quality index of fruit are not clearly shown in comparison with control one. A small priority is noticed in case of growth stimulators. In conditions of red soils, liquid organic fertilizers and growth stimulators added in the nutrition of the citrus more or less influence the dry material of fruit and the composition of ash and nutrition elements. Agro-chemical index of the soil, except exchange acidity, is somehow enlarged which is one of the positive results in this case.

Keywords: growth stimulator, liquid fertilizer, plant, fruit, soil

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8496 Potentials of Henna Leaves as Dye and Its Fastness Properties on Fabric

Authors: Nkem Angela Udeani

Abstract:

Despite the widespread use of synthetic dyes, natural dyes are still exploited and used to enhance its inherent aesthetic qualities as a major material for the beautification of the body. Centuries before the discovery of synthetic dye, natural dyes were the only source of dye open to mankind. Dyes are extracted from plant - leaves, roots, and barks, insect secretions, and minerals. However, research findings have made it clear that of all, plant- leaves, roots, barks or flowers are the most explored and exploited. Henna (Lawsonia innermis) is one of those plants. The experiment has also shown that henna is used in body painting in conjunction with an alkaline (Ammonium Sulphate) as a fixing agent. This of course gives a clue that if colour derived from henna is properly investigated, it may not only be used as body decoration but possibly, may have affinity to fibre substrate. This paper investigates the dyeing potentials - dyeing ability and fastness qualities of henna dye extract on cotton and linen fibres using mordants like ammonium sulphate and other alkalies (hydrosulphate and caustic soda, potash, common salt and alum). Hot and cold water and ethanol solvent were used in the extraction of the dye to investigate the most effective method of extraction, dyeing ability and fastness qualities of these extracts under room temperature. The results of the experiment show that cotton have a high rate of dye intake than linen fibre. On a similar note, the colours obtained depend most on the solvent and or the mordant used. In conclusion, hot water extraction appear more effective. While the colours obtained from ethanol and both cold and hot method of extraction range from light to dark yellow, light green to army green, there are to some extent shades of brown hues.

Keywords: dye, fabrics, henna leaves, potential

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8495 Resistance Training and Ginger Consumption on Cytokines Levels

Authors: Alireza Barari, Ahmad Abdi

Abstract:

Regular body trainings cause adaption in various system in body. One of the important effect of body training is its effect on immune system. It seems that cytokines usually release after long period exercises or some exercises which cause skeletal muscular damages. If some of the cytokines which cause responses such as inflammation of cells in skeletal muscles, with manipulating of training program, it can be avoided or limited from those exercises which induct cytokines release. Ginger plant is a kind of medicinal plants which is known as a anti inflammation plant. This plant is as most precedence medicinal plants in medicine science especially in inflammation cure. The aim of the present study was the effect of selected resistance training and consumption of ginger extract on IL-1α and TNFα untrained young women. The population includes young women interested in participating in the study with the average of 30±2 years old from Abbas Abad city among which 32 participants were chosen randomly and divided into 4 four groups, resistance training (R), resistance training and ginger consumption(RG), Ginger consumption(G)and Control group(C). The training groups performed circuit resistance training at the intensity of 65-75% one repeat maximum, 3 days a week for 6 weeks. Besides resistance training, subjects were given either ginseng (5 mg/kg per day) or placebo. Prior to and 48 hours after interventions body composition was measured and blood samples were taken in order to assess serum levels of IL-1α and TNFα. Plasma levels of cytokines were measured with commercially available ELISA Kits.IL-1α kit and TNFα kit were used in this research. To demonstrate the effectiveness of the independent variable and the comparison between groups, t-test and ANOVA were used. To determine differences between the groups, the Scheffe test was used that showed significant changes in any of the variables. we observed that circuit resistance training in R and RG groups can significant decreased in weight and body mass index in untrained females (p<0.05). The results showed a significant decreased in the mean level of IL-1α levels before and after the training period in G group (p=0.046) and RG group (p=0.022). Comparison between groups also showed there was significant difference between groups R-RG and RG-C. Intergroup comparison results showed that the mean levels of TNFα before and after the training in group G (p=0.044) and RG (p=0.037), significantly decreased. Comparison between groups also showed there was significant difference between groups R–RG , R-G ,RG-C and G-C. The research shows that circuit resistance training with reducing overload method results in systemic inflammation had significant effect on IL-1α levels and TNFα. Of course, Ginger can counteract the negative effects of resistance training exercise on immune function and stability of the mast cell membrane. Considerable evidence supported the anti-inflammatory properties of ginger for several constituents, especially gingerols, shogaols, paradols, and zingerones, through decreased cytokine gene TNF α and IL-1Α expression and inhibition of cyclooxygenase 1 and 2. These established biological actions suggest that ingested ginger could block the increase in IL-1α.

Keywords: resistance training, ginger, IL-1α , TNFα

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8494 The Gradient Complex Protective Coatings for Single Crystal Nickel Alloys

Authors: Evgeniya Popova, Vladimir Lesnikov, Nikolay Popov

Abstract:

High yield complex coatings have been designed for thermally stressed cooled HP turbine blades from single crystal alloys ZHS32-VI-VI and ZHS36 with crystallographic orientation [001]. These coatings provide long-term protection of single crystal blades during operation. The three-layer coatings were prepared as follows: the diffusion barrier layer formation on the alloy surface, the subsequent deposition of the condensed bilayer coatings consisting of an inner layer based on Ni-Cr-Al-Y systems and an outer layer based on the alloyed β-phase. The structure, phase composition of complex coatings and reaction zone interaction with the single-crystal alloys ZHS32-VI and ZHS36-VI were investigated using scanning electron microscope (SEM). The effect of complex protective coatings on the properties of heat-resistant nickel alloys was studied.

Keywords: single crystal nickel alloys, complex heat-resistant coatings, structure, phase composition, properties

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8493 Design and Simulation of Step Structure RF MEMS Switch for K Band Applications

Authors: G. K. S. Prakash, Rao K. Srinivasa

Abstract:

MEMS plays an important role in wide range of applications like biological, automobiles, military and communication engineering. This paper mainly investigates on capacitive shunt RF MEMS switch with low actuation voltage and low insertion losses. To trim the pull-in voltage, a step structure has introduced to trim air gap between the beam and the dielectric layer with that pull in voltage is trim to 2.9 V. The switching time of the proposed switch is 39.1μs, and capacitance ratio is 67. To get more isolation, we have used aluminum nitride as dielectric material instead of silicon nitride (Si₃N₄) and silicon dioxide (SiO₂) because aluminum nitride has high dielectric constant (εᵣ = 9.5) increases the OFF capacitance and eventually increases the isolation of the switch. The results show that the switch is ON state involves return loss (S₁₁) less than -25 dB up to 40 GHz and insertion loss (S₂₁) is more than -1 dB up to 35 GHz. In OFF state switch shows maximum isolation (S₂₁) of -38 dB occurs at a frequency of 25-27 GHz for K band applications.

Keywords: RF MEMS, actuation voltage, isolation loss, switches

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8492 Seed Associated Microbial Communities of Holoparasitic Cistanche Species from Armenia and Portugal

Authors: K. Petrosyan, R. Piwowarczyk, K. Ruraż, S. Thijs, J. Vangronsveld, W. Kaca

Abstract:

Holoparasitic plants are flowering heterotrophic angiosperms which with the help of an absorbing organ - haustorium, attach to another plant, the so-called the host. Due to the different hosts, unusual lifestyle, lack of roots, chlorophylls and photosynthesis, these plants are interesting and unique study objects for global biodiversity. The seeds germination of the parasitic plants also is unique: they germinate only in response to germination stimulants, namely strigolactones produced by the root of an appropriate host. Resistance of the seeds on different environmental conditions allow them to stay viable in the soil for more than 20 years. Among the wide range of plant protection mechanisms the endophytic communities have a specific role. In this way, they have the potential to mitigate the impacts of adverse conditions such as soil salinization. The major objective of our study was to compare the bacterial endo-microbiomes from seeds of two holoparasitic plants from Orobanchaceae family, Cistanche – C. armena (Armenia) and C. phelypaea (Portugal) – from saline habitats different in soil water status. The research aimed to perform how environmental conditions influence on the diversity of the bacterial communities of C. armena and C. phelypaea seeds. This was achieved by comparison of the endophytic microbiomes of two species and isolation of culturable bacteria. A combination of culture-dependent and molecular techniques was employed for the identification of the seed endomicrobiome (culturable and unculturable). Using the V3-V4 hypervariable region of the 16S rRNA gene, four main taxa were identified: Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes, but the relative proportion of the taxa was different in each type of seed. Generally, sixteen phyla, 323 genera and 710 bacterial species were identified, mainly Gram negative, halotolerant bacteria with an environmental origin. However, also some unclassified and unexplored taxonomic groups were found in the seeds of both plants. 16S rRNA gene sequencing analysis from both species identified the gram positive, endospore forming, halotolerant and alkaliphile Bacillus spp. which suggests that the endophytic bacteria of examined seeds possess traits that are correlated with the natural habitat of their hosts. The cultivable seed endophytes from C. armena and C. phelypaea were rather similar, notwithstanding the big distances between their growth habitats - Armenia and Portugal. Although the seed endophytic microbiomes of C. armena and C. phelypaea contain a high number of common bacterial taxa, also remarkable differences exist. We demonstrated that the environmental conditions or abiotic stresses influence on diversity of the bacterial communities of holoparasiotic seeds. To the best of our knowledge the research is the first report of endophytes from seeds of holoparasitic Cistanche armena and C. phelypaea plants.

Keywords: microbiome, parasitic plant, salinity, seeds

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8491 Dielectric Properties of Ternary Composite Based on Complex Perovskite Oxides Synthesized by Semi-Wet Route

Authors: K. D. Mandal, Anil Kumar Mourya, Ankur Khare

Abstract:

Ceramics of 0.6 CaCu3TiO12 – 0.2 Bi2/3Cu3TiO12 – 0.2 Y2/3Cu3TiO12 (i.e. 0.6CCTO-0.2BCTO-0.2 YCTO) were prepared via semi - wet route. The phase structure of the sample was identified by X-Ray diffraction. The micro structure of the sample was observed by SEM, which displays grains of different shapes having diameter in range of 2 µm–4 µm. We have studied the frequency and temperature dependence of permittivity and impedance of the compound with LCR Meter in the range of 100 Hz–1 MHz and 300–500 K. The material shows its highest dielectric constant (428000) at 100 Hz and 368 K. The material shows Debye–like relaxation and their dielectric constant are independent of frequency and temperature over a wide range. The sample shows two electrical responses in impedance formalism, indicating that there are two distinct contributions. We attribute them to grain and grain boundaries in the ceramic sample and explain the dielectric behaviors by Maxwell–Wagner relaxation arising at the interfaces between grain and their boundaries.

Keywords: complex perovskite, ceramics composite, impedance study, SEM

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8490 3D Quantum Simulation of a HEMT Device Performance

Authors: Z. Kourdi, B. Bouazza, M. Khaouani, A. Guen-Bouazza, Z. Djennati, A. Boursali

Abstract:

We present a simulation of a HEMT (high electron mobility transistor) structure with and without a field plate. We extract the device characteristics through the analysis of DC, AC and high frequency regimes, as shown in this paper. This work demonstrates the optimal device with a gate length of 15 nm, InAlN/GaN heterostructure and field plate structure, making it superior to modern HEMTs when compared with otherwise equivalent devices. This improves the ability to bear the burden of the current density passes in the channel. We have demonstrated an excellent current density, as high as 2.05 A/mm, a peak extrinsic transconductance of 590 mS/mm at VDS=2 V, and cutting frequency cutoffs of 638 GHz in the first HEMT and 463 GHz for Field plate HEMT., maximum frequency of 1.7 THz, maximum efficiency of 73%, maximum breakdown voltage of 400 V, DIBL=33.52 mV/V and an ON/OFF current density ratio higher than 1 x 1010. These values were determined through the simulation by deriving genetic and Monte Carlo algorithms that optimize the design and the future of this technology.

Keywords: HEMT, Silvaco, field plate, genetic algorithm, quantum

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8489 Genetic Variability and Heritability Among Indigenous Pearl Millet (Pennisetum Glaucum L. R. BR.) in Striga Infested Fields of Sudan Savanna, Nigeria

Authors: Adamu Usman, Grace Stanley Balami

Abstract:

Pearl millet (Pennisetum glaucum L. R. Br.) is a cereal cultivated in arid and semi-arid areas of the world. It supports more than 100 million people around the world. Parasitic weed (Striga hermonthica Del. Benth) is a major constraint to its production. Estimated yield losses are put at 10 - 95% depending on variety, ecology and cultural practices. Potentials in selection of traits in pearl millets for grain yield have been reported and it depends on genotypic variability and heritability among landraces. Variability and heritability among cultivars could offer opportunities for improvement. The study was conducted to determine the genetic variability among cultivars and estimate broad sense heritability among grain yield and related traits. F1 breeding populations were generated with 9 parental cultivars, viz; Ex-Gubio, Ex-Monguno, Ex-Baga as males and PEO 5984, Super-SOSAT, SOSAT-C88, Ex-Borno and LCIC9702 as females through Line × Tester mating during 2017 dry season at Lushi Irrigation Station, Bauchi Metropolitan in Bauchi State, Nigeria. The F1 population and the parents were evaluated during cropping season of 2018 at Bauchi and Maiduguri. Data collected were subjected to analysis of variance. Results showed significant difference among cultivars and among traits indicating variability. Number of plants at emergence, days to 50% flowering, days to 100% flowering, plant height, panicle length, number of plants at harvest, Striga count at 90 days after sowing, panicle weight and grain yield were significantly different. Significant variability offer opportunity for improvement as superior individuals can be isolated. Genotypic variance estimates of traits were largely greater than environmental variances except in plant height and 1000 seed weight. Environmental variances were low and in some cases negligible. The phenotypic variances of all traits were higher than genotypic variances. Similarly phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV). High heritability was found in days to 50% flowering (90.27%), Striga count at 90 days after sowing (90.07%), number of plants at harvest (87.97%), days to 100% flowering (83.89%), number of plants at emergence (82.19%) and plant height (73.18%). Greater heritability estimates could be due to presence of additive gene. The result revealed wider variability among genotypes and traits. Traits having high heritability could easily respond to selection. High value of GCV, PCV and heritability estimates indicate that selection for these traits are possible and could be effective.

Keywords: variability, heritability, phenotypic, genotypic, striga

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8488 Monte Carlo Risk Analysis of a Carbon Abatement Technology

Authors: Hameed Rukayat Opeyemi, Pericles Pilidis, Pagone Emanuele

Abstract:

Climate change represents one of the single most challenging problems facing the world today. According to the National Oceanic and Administrative Association, Atmospheric temperature rose almost 25% since 1958, Artic sea ice has shrunk 40% since 1959 and global sea levels have risen more than 5.5 cm since 1990. Power plants are the major culprits of GHG emission to the atmosphere. Several technologies have been proposed to reduce the amount of GHG emitted to the atmosphere from power plant, one of which is the less researched Advanced zero emission power plant. The advanced zero emission power plants make use of mixed conductive membrane (MCM) reactor also known as oxygen transfer membrane (OTM) for oxygen transfer. The MCM employs membrane separation process. The membrane separation process was first introduced in 1899 when Walter Hermann Nernst investigated electric current between metals and solutions. He found that when a dense ceramic is heated, current of oxygen molecules move through it. In the bid to curb the amount of GHG emitted to the atmosphere, the membrane separation process was applied to the field of power engineering in the low carbon cycle known as the Advanced zero emission power plant (AZEP cycle). The AZEP cycle was originally invented by Norsk Hydro, Norway and ABB Alstom power (now known as Demag Delaval Industrial turbo machinery AB), Sweden. The AZEP drew a lot of attention because its ability to capture ~100% CO2 and also boasts of about 30-50 % cost reduction compared to other carbon abatement technologies, the penalty in efficiency is also not as much as its counterparts and crowns it with almost zero NOx emissions due to very low nitrogen concentrations in the working fluid. The advanced zero emission power plants differ from a conventional gas turbine in the sense that its combustor is substituted with the mixed conductive membrane (MCM-reactor). The MCM-reactor is made up of the combustor, low temperature heat exchanger LTHX (referred to by some authors as air pre-heater the mixed conductive membrane responsible for oxygen transfer and the high temperature heat exchanger and in some layouts, the bleed gas heat exchanger. Air is taken in by the compressor and compressed to a temperature of about 723 Kelvin and pressure of 2 Mega-Pascals. The membrane area needed for oxygen transfer is reduced by increasing the temperature of 90% of the air using the LTHX; the temperature is also increased to facilitate oxygen transfer through the membrane. The air stream enters the LTHX through the transition duct leading to inlet of the LTHX. The temperature of the air stream is then increased to about 1150 K depending on the design point specification of the plant and the efficiency of the heat exchanging system. The amount of oxygen transported through the membrane is directly proportional to the temperature of air going through the membrane. The AZEP cycle was developed using the Fortran software and economic analysis was conducted using excel and Matlab followed by optimization case study. This paper discusses techno-economic analysis of four possible layouts of the AZEP cycle. The Simple bleed gas heat exchange layout (100 % CO2 capture), Bleed gas heat exchanger layout with flue gas turbine (100 % CO2 capture), Pre-expansion reheating layout (Sequential burning layout) – AZEP 85 % (85 % CO2 capture) and Pre-expansion reheating layout (Sequential burning layout) with flue gas turbine– AZEP 85 % (85 % CO2 capture). This paper discusses Montecarlo risk analysis of four possible layouts of the AZEP cycle.

Keywords: gas turbine, global warming, green house gases, power plants

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8487 Effects of Biocompatible Substrates on the Electrical Properties of Graphene

Authors: M. Simchi, M. Amiri, E. Rezvani, I. Mirzaei, M. Berahman, A. Simchi, M. Fardmanesh

Abstract:

Graphene is a single-atomic two-dimensional crystal of carbon atoms that has considerable properties due to its unique structure and physics with applications in different fields. Graphene has sensitive electrical properties due to its atomic-thin structure. Along with the substrate materials and their influence on the transport properties in graphene, design and fabrication of graphene-based devices for biomedical and biosensor applications are challenging. In this work, large-area high-quality graphene nanosheets were prepared by low pressure chemical vapor deposition using methane gas as carbon source on copper foil and transferred on the biocompatible substrates. Through deposition of titanium and gold contacts, current-voltage response of the transferred graphene on four biocompatible substrates, including PDMS, SU-8, Nitrocellulose, and Kapton (Fig. 2) were experimentally determined. The considerable effect of the substrate type on the electrical properties of graphene is shown. The sheet resistance of graphene is changed from 0.34 to 14.5 kΩ/sq, depending on the substrate.

Keywords: biocompatible substrates, electrical properties, graphene, sheet resistance

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8486 Plant Growth, Symbiotic Performance and Grain Yield of 63 Common Bean Genotypes Grown Under Field Conditions at Malkerns Eswatini

Authors: Rotondwa P. Gunununu, Mustapha Mohammed, Felix D. Dakora

Abstract:

Common bean is the most importantly high protein grain legume grown in Southern Africa for human consumption and income generation. Although common bean can associate with rhizobia to fix N₂ for bacterial use and plant growth, it is reported to be a poor nitrogen fixer when compared to other legumes. N₂ fixation can vary with legume species, genotype and rhizobial strain. Therefore, screening legume germplasm can reveal rhizobia/genotype combinations with high N₂-fixing efficiency for use by farmers. This study assessed symbiotic performance and N₂ fixation in 63 common bean genotypes under field conditions at Malkerns Station in Eswatini, using the ¹⁵N natural abundance technique. The shoots of common bean genotypes were sampled at a pod-filling stage, oven-dried (65oC for 72h), weighed, ground into a fine powder (0.50 mm sieve), and subjected to ¹⁵N/¹⁴N isotopic analysis using mass spectrometry. At maturity, plants from the inner rows were harvested for the determination of grain yield. The results revealed significantly higher modulation (p≤0.05) in genotypes MCA98 and CIM-RM01-97-8 relative to the other genotypes. Shoot N concentration was highest in genotype MCA 98, followed by KAB 10 F2.8-84, with most genotypes showing shoot N concentrations below 2%. Percent N derived from atmospheric N₂ fixation (%Ndfa) differed markedly among genotypes, with CIM-RM01-92-3 and DAB 174, respectively, recording the highest values of 66.65% and 66.22 % N derived from fixation. There were also significant differences in grain yield, with CIM-RM02-79-1 producing the highest yield (3618.75 kg/ha). These results represent an important contribution in the profiling of symbiotic functioning of common bean germplasm for improved N₂ fixation.

Keywords: nitrogen fixation, %Ndfa, ¹⁵N natural abundance, grain yield

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8485 Spin-Polarized Investigation of Ferromagnetism on Magnetic Semiconductors MnxCa1-xS in the Rock-salt Phase

Authors: B. Ghebouli, M. A. Ghebouli, H. Choutri, M. Fatmi, L. Louail

Abstract:

The structural, elastic, electronic and magnetic properties of the diluted magnetic semiconductors MnxCa1-xS in the rock-salt phase have been investigated using first-principles calculations. Features such as lattice constant, bulk modulus, elastic constants, spin-polarized band structure, total and local densities of states have been computed. We predict the values of the exchange constants and the band edge spin splitting of the valence and conduction bands. The hybridization between S-3p and Mn-3d produces small local magnetic moment on the nonmagnetic Ca and S sites. The ferromagnetism is induced due to the exchange splitting of S-3p and Mn-3d hybridized bands. The total magnetic moment per Mn of MnxCa1-xS is 4.4µB and is independent of the Mn concentration. The unfilled Mn -3d levels reduce the local magnetic moment of Mn from its free space charge value of 5µB to 4.4µB due to 3p–3d hybridization.

Keywords: semiconductors, Ab initio calculations, band-structure, magnetic properties

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8484 Predictions of Thermo-Hydrodynamic State for Single and Three Pads Gas Foil Bearings Operating at Steady-State Based on Multi-Physics Coupling Computer Aided Engineering Simulations

Authors: Tai Yuan Yu, Pei-Jen Wang

Abstract:

Oil-free turbomachinery is considered one of the critical technologies for future green power generation systems as rotor machinery systems. Oil-free technology allows clean, compact, and maintenance-free working, and gas foil bearings, abbreviated as GFBs, are important for the technology. Since the first applications in the auxiliary power units and air cycle machines in the 1970s, obvious improvement has been created to the computational models for dynamic rotor behavior. However, many technical issues are still poorly understood or remain unsolved, and some of those are thermal management and the pattern of how pressure will be distributed in bearing clearance. This paper presents a three-dimensional, abbreviated as 3D, fluid-structure interaction model of single pad foil bearings and three pad foil bearings to predict bearing working behavior that researchers could compare characteristics of those. The coupling analysis model involves dynamic working characteristics applied to all the gas film and mechanical structures. Therefore, the elastic deformation of foil structure and the hydrodynamic pressure of gas film can both be calculated by a finite element method program. As a result, the temperature distribution pattern could also be iteratively solved by coupling analysis. In conclusion, the working fluid state in a gas film of various pad forms of bearings working characteristic at constant rotational speed for both can be solved for comparisons with the experimental results.

Keywords: fluid-structure interaction, multi-physics simulations, gas foil bearing, oil-free, transient thermo-hydrodynamic

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8483 A Study on Information Structure in the Vajrachedika-Prajna-paramita Sutra and Translation Aspect

Authors: Yoon-Cheol Park

Abstract:

This research focuses on examining the information structures in the old Chinese character-Korean translation of the Vajrachedika-prajna-paramita sutra. The background of this research comes from the fact that there were no previous researches which looked into the information structures in the target text of the Vajrachedika-prajna-paramita sutra by now. The existing researches on the Buddhist scripture translation mainly put weight on message conveyance by literal and semantic translation methods. But the message conveyance from one language to another has a necessity to be delivered with equivalent information structure. Thus, this research is intended to investigate on the flow of old and new information in the target text of Buddhist scripture, compared with source text. The Vajrachedika-prajna-paramita sutra unlike other Buddhist scriptures is composed of conversational structures between Buddha and his disciple, Suboli. This implies that the information flow can be changed by utterance context and some propositions. So, this research tries to analyze the flow of old and new information within the source and target text. As a result of analysis, this research can discover the following facts; firstly, there are the differences of the information flow in the message conveyance between the old Chinese character and Korean by language features. The old Chinese character reveals that old-new information flow is developed, while Korean indicates new-old information flow because of word order. Secondly, the source text of the Vajrachedika-prajna-paramita sutra includes abstruse terminologies, jargon and abstract words. These make influence on the target text and cause the change of the information flow. But the repetitive expressions of these words provide the old information in the target text. Lastly, the Vajrachedika-prajna-paramita sutra offers the expository structure from conversations between Buddha and Suboli. It means that the information flow is developed in the way of explaining specific subjects and of paraphrasing unfamiliar phrases and expressions. From the results of analysis above, this research can verify that the information structures in the target text of the Vajrachedika-prajna-paramita sutra are changed by specific subjects and terminologies, developed with the new-old information flow by repetitive expressions or word order and reveal the information structures familiar to target culture. It also implies that the translation of the Vajrachedika-prajna-paramita sutra as a religious book needs the message conveyance to take into account the information structures of two languages.

Keywords: abstruse terminologies, the information structure, new and old information, old Chinese character-Korean translation

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8482 Phytochemical Screening and Hepatotoxic Effect of Datura metel Linn. Aqueous Seed Extract in Albino Wistar Rats

Authors: I. M. Fakai, A. Abdulhamid, I. Sani, F. Bello, E. O. Olusesi

Abstract:

The phytochemical screening and hepatotoxic effect of Datura metel aqueous seeds extract in Albino Wistar rats were evaluated. Phytochemicals were screened using standard methods. The enzymes activity and liver function indices were also determined using standard methods of analysis. The phytochemicals screening revealed the presence of alkaloid, tannin, glycoside and flavonoid. The organ-body weight decreased significantly (P<0.05) at all the doses of the extract treated groups compared to the control. The activity of alkaline phosphatase decreased significantly (P<0.05) in the liver and increased significantly in the serum at all the doses of the extract treated groups compared to the control. The activity of serum alanine transaminase increased significantly (P<0.05) while there is no significant difference (P>0.05) in the activity liver alanine transaminase at all the doses of the extract treated groups compared to the control. The result also revealed significant increase (P<0.05) in the aspartate transaminase activity in both liver and serum at all doses of the extract treated groups compared to the control. Serum total protein, albumin, globulin, and total bilirubin concentration decreased significantly (P<0.05), while direct bilirubin concentration increased significantly (P<0.05) at all the doses of the extract treated groups compared to the control. The present study therefore revealed that, the present of some phytochemicals in the plant extract attributed the plant to its hepatotoxic effects as revealed in the alteration of marker enzymes and some liver function indices analyzed.

Keywords: datura metel, transaminases, hepatotoxic effect, phytochemicals, rats

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8481 Status and Management of Grape Stem Borer, Celosterna scrabrator with Soil Application of Chlorantraniliprole 0.4 gr

Authors: D. N. Kambrekar, S. B. Jagginavar, J. Aruna

Abstract:

Grape stem borer, Celosterna scrabrator is an important production constraint in grapes in India. Hitherto this pest was a severe menace only on the aged and unmanaged fields but during the recent past it has also started damaging the newly established fields. In India, since Karnataka, Andra Pradesh, Tamil Nadu and Maharashtra are the major grape production states, the incidence of stem borer is also restricted and severe in these states. The grubs of the beetle bore in to the main stem and even the branches, which affect the translocation of nutrients to the areal parts of the plant. Since, the grubs bore inside the stem, the chewed material along with its excreta is discharged outside the holes and the frass is found on the ground just below the bored holes. The portion of vines above the damaged part has a sticky appearance. The leaves become pale yellow which looks like a deficiency of micronutrients. The leaves ultimately dry and drop down. The status of the incidence of the grape stem borer in different grape growing districts of Northern Karnataka was carried out during three years. In each taluka five locations were surveyed for the incidence of grape stem borer. Further, the experiment on management of stem borer was carried out in the grape gardens of Vijayapur districts under farmers field during three years. Stem borer infested plants that show live holes were selected per treatments and it was replicated three times. Live and dead holes observed during pre-treatment were closely monitored and only plants with live holes were selected and tagged. Different doses of chlorantraniliprole 0.4% GR were incorporated into the soil around the vine basins near root zone surrounded to trunk region by removing soils up to 5-10 cm with a peripheral distance of 1 to 1.5 feet from the main trunk where feeder roots are present. Irrigation was followed after application of insecticide for proper incorporation of the test chemical. The results indicated that there was sever to moderate incidence of the stem borer in all the grape growing districts of northern Karnataka. Maximum incidence was recorded in Belagavi (11 holes per vine) and minimum was in Gadag district (8.5 holes per vine). The investigations carried out to study the efficacy of chlorantraniliprole on grape stem borer for successive three years under farmers field indicated that chlorantraniliprole @ 15g/vine applied just near the active root zone of the plant followed by irrigation has successfully managed the pest. The insecticide has translocated to all the parts of the plants and thereby stopped the activity of the pest which has resulted in to better growth of the plant and higher berry yield compared to other treatments under investigation. Thus, chlorantraniliprole 0.4 GR @ 15g/vine can be effective means in managing the stem borer.

Keywords: chlorantraniliprole, grape stem borer, Celosterna scrabrator, management

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8480 Macroscopic Support Structure Design for the Tool-Free Support Removal of Laser Powder Bed Fusion-Manufactured Parts Made of AlSi10Mg

Authors: Tobias Schmithuesen, Johannes Henrich Schleifenbaum

Abstract:

The additive manufacturing process laser powder bed fusion offers many advantages over conventional manufacturing processes. For example, almost any complex part can be produced, such as topologically optimized lightweight parts, which would be inconceivable with conventional manufacturing processes. A major challenge posed by the LPBF process, however, is, in most cases, the need to use and remove support structures on critically inclined part surfaces (α < 45 ° regarding substrate plate). These are mainly used for dimensionally accurate mapping of part contours and to reduce distortion by absorbing process-related internal stresses. Furthermore, they serve to transfer the process heat to the substrate plate and are, therefore, indispensable for the LPBF process. A major challenge for the economical use of the LPBF process in industrial process chains is currently still the high manual effort involved in removing support structures. According to the state of the art (SoA), the parts are usually treated by simple hand tools (e.g., pliers, chisels) or by machining (e.g., milling, turning). New automatable approaches are the removal of support structures by means of wet chemical ablation and thermal deburring. According to the state of the art, the support structures are essentially adapted to the LPBF process and not to potential post-processing steps. The aim of this study is the determination of support structure designs that are adapted to the mentioned post-processing approaches. In the first step, the essential boundary conditions for complete removal by means of the respective approaches are identified. Afterward, a representative demonstrator part with various macroscopic support structure designs will be LPBF-manufactured and tested with regard to a complete powder and support removability. Finally, based on the results, potentially suitable support structure designs for the respective approaches will be derived. The investigations are carried out on the example of the aluminum alloy AlSi10Mg.

Keywords: additive manufacturing, laser powder bed fusion, laser beam melting, selective laser melting, post processing, tool-free, wet chemical ablation, thermal deburring, aluminum alloy, AlSi10Mg

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8479 Introduction of Para-Sasaki-Like Riemannian Manifolds and Construction of New Einstein Metrics

Authors: Mancho Manev

Abstract:

The concept of almost paracontact Riemannian manifolds (abbr., apcR manifolds) was introduced by I. Sato in 1976 as an analogue of almost contact Riemannian manifolds. The notion of an apcR manifold of type (p,q) was defined by S. Sasaki in 1980, where p and q are respectively the numbers of the multiplicity of the structure eigenvalues 1 and -1. It also has a simple eigenvalue of 0. In our work, we consider (2n+1)-dimensional apcR manifolds of type (n,n), i.e., the paracontact distribution of the studied manifold can be considered as a 2n-dimensional almost paracomplex Riemannian distribution with almost paracomplex structure and structure group O(n) × O(n). The aim of the present study is to introduce a new class of apcR manifolds. Such a manifold is obtained using the construction of a certain Riemannian cone over it, and the resulting manifold is a paraholomorphic paracomplex Riemannian manifold (abbr., phpcR manifold). We call it a para-Sasaki-like Riemannian manifold (abbr., pSlR manifold) and give some explicit examples. We study the structure of pSlR spaces and find that the paracontact form η is closed and each pSlR manifold locally can be considered as a certain product of the real line with a phpcR manifold, which is locally a Riemannian product of two equidimensional Riemannian spaces. We also obtain that the curvature of the pSlR manifolds is completely determined by the curvature of the underlying local phpcR manifold. Moreover, the ξ-directed Ricci curvature is equal to -2n, while in the Sasaki case, it is 2n. Accordingly, the pSlR manifolds can be interpreted as the counterpart of the Sasaki manifolds; the skew-symmetric part of ∇η vanishes, while in the Sasaki case, the symmetric part vanishes. We define a hyperbolic extension of a (complete) phpcR manifold that resembles a certain warped product, and we indicate that it is a (complete) pSlR manifold. In addition, we consider the hyperbolic extension of a phpcR manifold and prove that if the initial manifold is a complete Einstein manifold with negative scalar curvature, then the resulting manifold is a complete Einstein pSlR manifold with negative scalar curvature. In this way, we produce new examples of a complete Einstein Riemannian manifold with negative scalar curvature. Finally, we define and study para contact conformal/homothetic deformations by deriving a subclass that preserves the para-Sasaki-like condition. We then find that if we apply a paracontact homothetic deformation of a pSlR space, we obtain that the Ricci tensor is invariant.

Keywords: almost paracontact Riemannian manifolds, Einstein manifolds, holomorphic product manifold, warped product manifold

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8478 The Jury System in the Courts in Nineteenth Century Assam: Power Negotiations and Politics in an Institutional Rubric of a Colonial Regime

Authors: Jahnu Bharadwaj

Abstract:

In the third decade of the 19th century, the political landscape of the Brahmaputra valley changed at many levels. The establishment of East India Company’s authority in ‘Assam’ was complete with the Treaty of Yandaboo. The whole phenomenon of the annexation of Assam into the British Indian Empire led to several administrative reorganizations and reforms under the new regime. British colonial rule was distinguished by new systems and institutions of governance. This paper broadly looks at the historical proceedings of the introduction of the Rule of Law and a new legal structure in the region of ‘Assam’. With numerous archival data, this paper seeks to chiefly examine the trajectory of an important element in the new legal apparatus, i.e. the jury in the British criminal courts introduced in the newly annexed region. Right from the beginning of colonial legal innovations with the establishment of the panchayats and the parallel courts in Assam, the jury became an important element in the structure of the judicial system. In both civil and criminal courts, the jury was to be formed from the learned members of the ‘native’ society. In the working of the criminal court, the jury became significantly powerful and influential. The structure meant that the judge or the British authority eventually had no compulsion to obey the verdict of the jury. However, the structure also provided that the jury had a considerable say in matters of the court proceedings, and their verdict had significant weight. This study seeks to look at certain important criminal cases pertaining to the nineteenth century and the functioning of the jury in those cases. The power play at display between the British officials, judges and the members of the jury would be helpful in highlighting the important deliberations and politics that were in place in the functioning of the British criminal legal apparatus in colonial Assam. The working and the politics of the members of the jury in many cases exerted considerable influence in the court proceedings. The interesting negotiations of the British officials or judges also present us with vital insights. By reflecting on the difficulty that the British officials and judges felt with the considerable space for opinion and difference that was provided to important members of the local society, this paper seeks to locate, with evidence, the racial politics at play within the official formulations of the legal apparatus in the colonial rule in Assam. This study seeks to argue that despite the rhetorical claims of legal equality within the Empire, racial consideration and racial politics was a reality even in the making of the structure itself. This in a way helps to enrich our ideas about the racial elements at work in numerous layers sustaining the colonial regime.

Keywords: criminal courts, colonial regime, jury, race

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8477 Phyto-Therapeutic, Functional and Nutritional Acclaims of Turnip (Brassica rapus L.): An Overview

Authors: Tabussam Tufail

Abstract:

Purpose: The core purpose of the current review article is to elaborate the phytochemicals present in turnip (brassica rapus l.) and also allied health claims. Plant-based foods contain a significant amount of bioactive compounds which provide desirable health benefits beyond the basic nutrition. Epidemiological evidence suggests that consumption of a diet rich in vegetables and fruits has positive implications for human health. Design: Potential of turnip peroxidase (TP) for the treatment of phenolic-contaminated solutions has been reviewed. However, issues of taste along with behavioral nutrition ought to be considered. So in the last decades, special attention has been paid towards edible plants, especially those that are rich in secondary metabolites (frequently called phytochemicals) and nowadays, there is an increasing interest in the antioxidant activity of such phytochemicals present in the diet. These chemicals favor nutritional and phytotherapy that is emerging as new concepts of health aid in recent years. Turnip is rich in these valuable ingredients though it can be employed as having health promoting and healing properties. Findings: Numerous bioactive components i.e. organic acids, phenolic compounds, turnip peroxidase, kaempeferol, vitamin-K, etc. are present in turnip. The review focused on the significance of plant derived (especially turnip) phenolic compounds as a source of certain beneficial compounds for human health. Owing to the presence of bioactive moieties, the turnip has high antioxidant activity, positive role in blood clotting, effectual in phenobarbital-induced sleeping time, effective against hepatic injury in diabetics and also have a good hepatoprotective role. Strong recommendations for consumption of nutraceuticals from turnip have become progressively popular to improve health, and to prevent from diseases.

Keywords: phytochemicals, turnip, antioxidants, health benefits

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8476 Preliminary Assessment for Protective Effect of Rhodiola rosea in Chemically Induced Ulcerative Colitis

Authors: Santram Lodhi, Alok Pal Jain, Awesh K. Yadav, Gopal Rai

Abstract:

Rhodiola rosea L. (Crassulaceae) is commonly known as golden root or rose root. It is a perennial herbaceous plant and most investigated species of the genus Rhodiola. Rhodiola rosea contains flavonoids, terpenoids, phenylpropanoid glycosides and phenylethanol derivatives in the roots of the plant. The objective of present study was to investigate the protective effect of hydroalcoholic extract from Rhodiola rosea roots in DSS induced colitis in mice. The ulcerative colitis was induced by DSS (3%, w/v) in mice and estimated weight loss and stool consistency. Various parameters including Colon length, spleen weights and ulcer index were also measured. The histological observations were observed by H&E staining. Effect of hydroalcoholic extract on various antioxidant parameter of rat colon such as tissue myeloperoxidase (MPO), reduced GSH, SOD concentrations and lipid peroxidation were determined. Pro-inflammatory mediators, such as tumour necrosis factor-α (TNF-α) and nitric oxide (NO) were determined by ELISA. In DSS induced group, mice body weight decreased gradually as compared to the control group. Redness and edema were observed in the colons intensely and scores representing inflammation in this group. The extract treated showed with tissue levels of TNF-α, IL-6 and MPO activity were significantly (p<0.05) increased. The mice treated with higher doses of hydroalcoholic extract (300 mg/kg) significantly reduced the activity compared with standard drug sulfasalazine (100 mg/kg. B.wt). Conclusion: Results of this study were suggested that the efficacy of hydroalcoholic extract, especially at the higher dose, was similar to that of standard drug, which concerned its potential application as a natural medicine for the treatment of ulcerative colitis.

Keywords: phenylpropanoid, Rhodiola rosea, sulfasalazin, ulcerative colitis

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8475 Morphological Analysis of Manipuri Language: Wahei-Neinarol

Authors: Y. Bablu Singh, B. S. Purkayashtha, Chungkham Yashawanta Singh

Abstract:

Morphological analysis forms the basic foundation in NLP applications including syntax parsing Machine Translation (MT), Information Retrieval (IR) and automatic indexing in all languages. It is the field of the linguistics; it can provide valuable information for computer based linguistics task such as lemmatization and studies of internal structure of the words. Computational Morphology is the application of morphological rules in the field of computational linguistics, and it is the emerging area in AI, which studies the structure of words, which are formed by combining smaller units of linguistics information, called morphemes: the building blocks of words. Morphological analysis provides about semantic and syntactic role in a sentence. It analyzes the Manipuri word forms and produces several grammatical information associated with the words. The Morphological Analyzer for Manipuri has been tested on 3500 Manipuri words in Shakti Standard format (SSF) using Meitei Mayek as source; thereby an accuracy of 80% has been obtained on a manual check.

Keywords: morphological analysis, machine translation, computational morphology, information retrieval, SSF

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8474 The Role of Home Composting in Waste Management Cost Reduction

Authors: Nahid Hassanshahi, Ayoub Karimi-Jashni, Nasser Talebbeydokhti

Abstract:

Due to the economic and environmental benefits of producing less waste, the US Environmental Protection Agency (EPA) introduces source reduction as one of the most important means to deal with the problems caused by increased landfills and pollution. Waste reduction involves all waste management methods, including source reduction, recycling, and composting, which reduce waste flow to landfills or other disposal facilities. Source reduction of waste can be studied from two perspectives: avoiding waste production, or reducing per capita waste production, and waste deviation that indicates the reduction of waste transfer to landfills. The present paper has investigated home composting as a managerial solution for reduction of waste transfer to landfills. Home composting has many benefits. The use of household waste for the production of compost will result in a much smaller amount of waste being sent to landfills, which in turn will reduce the costs of waste collection, transportation and burial. Reducing the volume of waste for disposal and using them for the production of compost and plant fertilizer might help to recycle the material in a shorter time and to use them effectively in order to preserve the environment and reduce contamination. Producing compost in a home-based manner requires very small piece of land for preparation and recycling compared with other methods. The final product of home-made compost is valuable and helps to grow crops and garden plants. It is also used for modifying the soil structure and maintaining its moisture. The food that is transferred to landfills will spoil and produce leachate after a while. It will also release methane and greenhouse gases. But, composting these materials at home is the best way to manage degradable materials, use them efficiently and reduce environmental pollution. Studies have shown that the benefits of the sale of produced compost and the reduced costs of collecting, transporting, and burying waste can well be responsive to the costs of purchasing home compost machine and the cost of related trainings. Moreover, the process of producing home compost may be profitable within 4 to 5 years and as a result, it will have a major role in reducing waste management.

Keywords: compost, home compost, reducing waste, waste management

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8473 Topology Optimization of Structures with Web-Openings

Authors: D. K. Lee, S. M. Shin, J. H. Lee

Abstract:

Topology optimization technique utilizes constant element densities as design parameters. Finally, optimal distribution contours of the material densities between voids (0) and solids (1) in design domain represent the determination of topology. It means that regions with element density values become occupied by solids in design domain, while there are only void phases in regions where no density values exist. Therefore the void regions of topology optimization results provide design information to decide appropriate depositions of web-opening in structure. Contrary to the basic objective of the topology optimization technique which is to obtain optimal topology of structures, this present study proposes a new idea that topology optimization results can be also utilized for decision of proper web-opening’s position. Numerical examples of linear elastostatic structures demonstrate efficiency of methodological design processes using topology optimization in order to determinate the proper deposition of web-openings.

Keywords: topology optimization, web-opening, structure, element density, material

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8472 Case-Based Reasoning for Modelling Random Variables in the Reliability Assessment of Existing Structures

Authors: Francesca Marsili

Abstract:

The reliability assessment of existing structures with probabilistic methods is becoming an increasingly important and frequent engineering task. However probabilistic reliability methods are based on an exhaustive knowledge of the stochastic modeling of the variables involved in the assessment; at the moment standards for the modeling of variables are absent, representing an obstacle to the dissemination of probabilistic methods. The framework according to probability distribution functions (PDFs) are established is represented by the Bayesian statistics, which uses Bayes Theorem: a prior PDF for the considered parameter is established based on information derived from the design stage and qualitative judgments based on the engineer past experience; then, the prior model is updated with the results of investigation carried out on the considered structure, such as material testing, determination of action and structural properties. The application of Bayesian statistics arises two different kind of problems: 1. The results of the updating depend on the engineer previous experience; 2. The updating of the prior PDF can be performed only if the structure has been tested, and quantitative data that can be statistically manipulated have been collected; performing tests is always an expensive and time consuming operation; furthermore, if the considered structure is an ancient building, destructive tests could compromise its cultural value and therefore should be avoided. In order to solve those problems, an interesting research path is represented by investigating Artificial Intelligence (AI) techniques that can be useful for the automation of the modeling of variables and for the updating of material parameters without performing destructive tests. Among the others, one that raises particular attention in relation to the object of this study is constituted by Case-Based Reasoning (CBR). In this application, cases will be represented by existing buildings where material tests have already been carried out and an updated PDFs for the material mechanical parameters has been computed through a Bayesian analysis. Then each case will be composed by a qualitative description of the material under assessment and the posterior PDFs that describe its material properties. The problem that will be solved is the definition of PDFs for material parameters involved in the reliability assessment of the considered structure. A CBR system represent a good candi¬date in automating the modelling of variables because: 1. Engineers already draw an estimation of the material properties based on the experience collected during the assessment of similar structures, or based on similar cases collected in literature or in data-bases; 2. Material tests carried out on structure can be easily collected from laboratory database or from literature; 3. The system will provide the user of a reliable probabilistic description of the variables involved in the assessment that will also serve as a tool in support of the engineer’s qualitative judgments. Automated modeling of variables can help in spreading probabilistic reliability assessment of existing buildings in the common engineering practice, and target at the best intervention and further tests on the structure; CBR represents a technique which may help to achieve this.

Keywords: reliability assessment of existing buildings, Bayesian analysis, case-based reasoning, historical structures

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