Search results for: asymmetrical growth
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 6301

Search results for: asymmetrical growth

5071 A Phase Field Approach to Model Crack Interface Interaction in Ceramic Matrix Composites

Authors: Dhaladhuli Pranavi, Amirtham Rajagopal

Abstract:

There are various failure modes in ceramic matrix composites; notable ones are fiber breakage, matrix cracking and fiber matrix debonding. Crack nucleation and propagation in microstructure of such composites requires an understanding of interaction of crack with the multiple inclusion heterogeneous system and interfaces. In order to assess structural integrity, the material parameters especially of the interface that governs the crack growth should be determined. In the present work, a nonlocal phase field approach is proposed to model the crack interface interaction in such composites. Nonlocal approaches help in understanding the complex mechanisms of delamination growth and mitigation and operates at a material length scale. The performance of the proposed formulation is illustrated through representative numerical examples. The model proposed is implemented in the framework of the finite element method. Several parametric studies on interface crack interaction are conducted. The proposed model is easy and simple to implement and works very well in modeling fracture in composite systems.

Keywords: composite, interface, nonlocal, phase field

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5070 Self-Regenerating, Vascularizing Hybrid Scaffold-Hydrogel For Bone Tissue Engineering

Authors: Alisha Gupta

Abstract:

Osteoarthritis (OA) is the most common form of arthritis which is a degenerative joint disease causing joints to begin to break down and underlying bones to change. This “wear and tear” most frequently affects hands, hips, and knees. This is important because OA pain is considered to be a leading cause of mobility impairment in older adults, with hip and knee OA ranked 11th highest contributors to global disability. Bone tissue engineering utilizing polymer scaffolds and hydrogels is an emerging field for treating osteoarthritis. Polymer scaffolds provide a three-dimensional structure for tissue growth, and hydrogels can be used to deliver drugs and growth factors. The combination of the two materials creates a hybrid structure that can better withstand physiological and mechanical demands while also providing a more controlled environment for drug and nutrient delivery. I think using bone tissue engineering for making scaffold-hydrogel composites that are self-regenerating and vascularizing might be useful in solving this problem. Successful implementation can reconstruct healthy, simulated bone tissue on deficient applicants.

Keywords: tissue engineering, regenerative medicine, scaffold-hydrogel composites, osteoarthritis

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5069 Comparative Proteomic Analysis of Rice bri1 Mutant Leaves at Jointing-Booting Stage

Authors: Jiang Xu, Daoping Wang, Yinghong Pan

Abstract:

The jointing-booting stage is a critical period of both vegetative growth and reproductive growth in rice. Therefore, the proteomic analysis of the mutant Osbri1, whose corresponding gene OsBRI1 encodes the putative BRs receptor OsBRI1, at jointing-booting stage is very important for understanding the effects of BRs on vegetative and reproductive growth. In this study, the proteomes of leaves from an allelic mutant of the DWARF 61 (D61, OsBRI1) gene, Fn189 (dwarf54, d54) and its wild-type variety T65 (Taichung 65) at jointing-booting stage were analysed by using a Q Exactive plus orbitrap mass spectrometer, and more than 3,100 proteins were identified in each sample. Ontology analysis showed that these proteins distribute in various space of the cells, such as the chloroplast, mitochondrion, and nucleus, they functioned as structural components and/or catalytic enzymes and involved in many physiological processes. Moreover, quantitative analysis displayed that 266 proteins were differentially expressed in two samples, among them, 77 proteins decreased and 189 increased more than two times in Fn189 compared with T65, the proteins whose content decreased in Fn189 including b5-like Heme/Steroid binding domain containing protein, putative retrotransposon protein, putative glutaminyl-tRNA synthetase, and higher content proteins such as mTERF, putative Oligopeptidase homologue, zinc knuckle protein, and so on. A former study founded that the transcription level of a mTERF was up-regulated in the leaves of maize seedling after EBR treatment. In our experiments, it was interesting that one mTERF protein increased, but another mTERF decreased in leaves of Fn189 at jointing-booting stage, which suggested that BRs may have differential regulation mechanisms on the expression of various mTERF proteins. The relationship between other differential proteins with BRs is still unclear, and the effects of BRs on rice protein contents and its regulation mechanisms still need further research.

Keywords: bri1 mutant, jointing-booting stage, proteomic analysis, rice

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5068 Dynamics of Follicle Vascular Perfusion, Dimensions, Antrum Growth, Circulating Angiogenic Mediators from Deviation to Ovulation

Authors: Elshymaa A. Abdelnaby, Amal M. Abo El-Maaty

Abstract:

This study aimed to investigate dynamics of dominant and subordinate follicles change in dimensions, vascularity and angiogenic hormones after completing deviation till ovulation. Five cyclic mares were subjected to daily blood sampling and rectal Doppler ultrasonographic examination along two estrous cycles. Using electronic calipers, three diameters were recorded for each follicle to estimate area and volume. Leptin, Insulin-like growth factor-I (IGF-1), nitric oxide (NO) and estradiol (E2) were measured. Area of color- and power- Doppler modes with area and circumference of the first (preovulatory) and subordinate follicles were measured in pixels. Follicles were classified into F1O (preovulatory), F2O (subordinate), F3O (third ovulatory) on the dominant ovary and F1C (first contra) and F2C (second contra) on the contralateral ovary. Days before ovulation significantly (P < 0.0001) affected diameter, circumference, area, volume, area/pixel and antrum area of the preovulatory follicle. With the increase of diameter, area, volume area/pixel, antrum area/pixel and circumference of F1O, those of all subordinates were decreasing. The blue blood flow area, power and power minus red blood flow area of F1O increased from day -6 till day of ovulation (day 0), but red blood flow area significantly decreased. F1O had the lowest percent of colored pixels and percent of the colored pixels without antrum. Estradiol and leptin increased from day -6 till day 0 but IGF-1 decreased till day -1 but NO achieved a peak on day -3 then decreased till day 0. In conclusion, antrum growth, blood flow and angiogenic hormones play a role in maturation and ovulation of the dominant follicle in mares.

Keywords: angiogenic hormones, blood flow, mare, preovulatory follicle

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5067 Preparing Entrepreneurial Women: A Challenge for Indian Education System

Authors: Dinesh Khanduja, Pardeep Kumar Sharma

Abstract:

Education as the most important resource in any country has multiplying effects on all facets of development in a society. The new social realities, particularly, the interplay between democratization of education; unprecedented developments in the IT sector; emergence of knowledge society, liberalization of economy, and globalization have greatly influenced the educational process of all nations. This turbulence entails upon education to undergo dramatic changes to keep up with the new expectations. Growth of entrepreneurship among Indian women is highly important for empowering them and this is highly essential for the socio-economic development of a society. Unfortunately, in India, there is poor acceptance of entrepreneurship among women as unfounded myths and fears restrain them to be enterprising. To remove these inhibitions, the education system needs to be re-engineered to make entrepreneurship more acceptable. This paper empirically analyses the results of a survey done on around 500 female graduates in North India to measure and evaluate various entrepreneurial traits present in them. A formative model has been devised in this context, which should improve the teaching-learning process in our education system, which can lead to a sustainable growth of women entrepreneurship in India.

Keywords: women empowerment, entrepreneurship, education system, women entrepreneurship, sustainable development

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5066 The Effect of Mgo and Rubber Nanofillers on Electrical Treeing Characteristic of XLPE Based Nanocomposites

Authors: Nur Amira nor Arifin, Tashia Marie Anthony, Mohd Ruzlin Mokhtar, Huzainie Shafi Abd Halim

Abstract:

Cross-linked polyethylene (XLPE) material is being used as the cable insulation for the past decades due to its higher working temperature of 90 ˚C and some other advantages. However, the use of XLPE as an insulating material for underground distribution cables may have subjected to the unforeseeable weather and uncontrollable environmental condition. These unfavorable condition when combine with high electric field may lead to the initiation and growth of water tree in XLPE insulation. There are several studies on numerous nanofillers incorporate into polymer matrix to hinder the growth of tree propagation. Hence, in this study aims to investigate the effect of MgO and rubber nanofillers at different concentration on the electrical tree of XLPE. The nanofillers and XLPE were mixed and later extruded. After extrusion, the material were then fabricated into the desired shape for experimental purposes. The result shows that the electrical tree propagation of XLPE filled with optimize concentration of nanofillers were much slower compared to pure XLPE. In this paper, the effect of nanofillers towards electrical treeing characteristic will be discussed.

Keywords: electrical trees, nanofillers, polymer nanocomposites, XLPE

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5065 Breeding Cotton for Annual Growth Habit: Remobilizing End-of-season Perennial Reserves for Increased Yield

Authors: Salman Naveed, Nitant Gandhi, Grant Billings, Zachary Jones, B. Todd Campbell, Michael Jones, Sachin Rustgi

Abstract:

Cotton (Gossypium spp.) is the primary source of natural fiber in the U.S. and a major crop in the Southeastern U.S. Despite constant efforts to increase the cotton fiber yield, the yield gain has stagnated. Therefore, we undertook a novel approach to improve the cotton fiber yield by altering its growth habit from perennial to annual. In this effort, we identified genotypes with high-expression alleles of five floral induction and meristem identity genes (FT, SOC1, FUL, LFY, and AP1) from an upland cotton mini-core collection and crossed them in various combinations to develop cotton lines with annual growth habit, optimal flowering time and enhanced productivity. To facilitate the characterization of genotypes with the desired combinations of stacked alleles, we identified markers associated with the gene expression traits via genome-wide association analysis using a 63K SNP Array (Hulse-Kemp et al. 2015 G3 5:1187). Over 14,500 SNPs showed polymorphism and were used for association analysis. A total of 396 markers showed association with expression traits. Out of these 396 markers, 159 mapped to genes, 50 to untranslated regions, and 187 to random genomic regions. Biased genomic distribution of associated markers was observed where more trait-associated markers mapped to the cotton D sub-genome. Many quantitative trait loci coincided at specific genomic regions. This observation has implications as these traits could be bred together. The analysis also allowed the identification of candidate regulators of the expression patterns of these floral induction and meristem identity genes whose functions will be validated via virus-induced gene silencing.

Keywords: cotton, GWAS, QTL, expression traits

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5064 Construction of Large Scale UAVs Using Homebuilt Composite Techniques

Authors: Brian J. Kozak, Joshua D. Shipman, Peng Hao Wang, Blake Shipp

Abstract:

The unmanned aerial system (UAS) industry is growing at a rapid pace. This growth has increased the demand for low cost, custom made and high strength unmanned aerial vehicles (UAV). The area of most growth is in the area of 25 kg to 200 kg vehicles. Vehicles this size are beyond the size and scope of simple wood and fabric designs commonly found in hobbyist aircraft. These high end vehicles require stronger materials to complete their mission. Traditional aircraft construction materials such as aluminum are difficult to use without machining or advanced computer controlled tooling. However, by using general aviation composite aircraft homebuilding techniques and materials, a large scale UAV can be constructed cheaply and easily. Furthermore, these techniques could be used to easily manufacture cost made composite shapes and airfoils that would be cost prohibitive when using metals. These homebuilt aircraft techniques are being demonstrated by the researchers in the construction of a 75 kg aircraft.

Keywords: composite aircraft, homebuilding, unmanned aerial system industry, UAS, unmanned aerial vehicles, UAV

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5063 Ecology, Value-Form and Metabolic Rift: Conceptualizing the Environmental History of the Amazon in the Capitalist World-System (19th-20th centuries)

Authors: Santiago Silva de Andrade

Abstract:

In recent decades, Marx's ecological theory of the value-form and the theory of metabolic rift have represented fundamental methodological innovations for social scientists interested in environmental transformations and their relationships with the development of the capital system. However, among Latin American environmental historians, such theoretical and methodological instruments have been used infrequently and very cautiously. This investigation aims to demonstrate how the concepts of metabolic rift and ecological value-form are important for understanding the environmental, economic and social transformations in the Amazon region between the second half of the 19th century and the end of the 20th century. Such transformations manifested themselves mainly in two dimensions: the first concerns the link between the manufacture of tropical substances for export and scientific developments in the fields of botany, chemistry and agriculture. This link was constituted as a set of social, intellectual and economic relations that condition each other, configuring an asymmetrical field of exchanges and connections between the demands of the industrialized world - personified in scientists, naturalists, businesspeople and bureaucrats - and the agencies of local social actors, such as indigenous people, riverside dwellers and quilombolas; the second dimension concerns the imperative link between the historical development of the capitalist world-system and the restructuring of the natural world, its landscapes, biomes and social relations, notably in peripheral colonial areas. The environmental effects of capitalist globalization were not only seen in the degradation of exploited environments, although this has been, until today, its most immediate and noticeable aspect. There was also, in territories subject to the logic of market accumulation, the reformulation of patterns of authority and institutional architectures, such as property systems, political jurisdictions, rights and social contracts, as a result of the expansion of commodity frontiers between the 16th and 21st centuries. . This entire set of transformations produced impacts on the ecological landscape of the Amazon. This demonstrates the need to investigate the histories of local configurations of power, spatial and ecological - with their institutions and social actors - and their role in structuring the capitalist world-system , under the lens of the ecological theory of value-form and metabolic rift.

Keywords: amazon, ecology, form-value, metabolic rift

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5062 Removal of Pb²⁺ from Waste Water Using Nano Silica Spheres Synthesized on CaCO₃ as a Template: Equilibrium and Thermodynamic Studies

Authors: Milton Manyangadze, Joseph Govha, T. Bala Narsaiah, Ch. Shilpa Chakra

Abstract:

The availability and access to fresh water is today a serious global challenge. This has been a direct result of factors such as the current rapid industrialization and industrial growth, persistent droughts in some parts of the world, especially in the sub-Saharan Africa as well as population growth. Growth of the chemical processing industry has also seen an increase in the levels of pollutants in our water bodies which include heavy metals among others. Heavy metals are known to be dangerous to both human and aquatic life. As such, they have been linked to several diseases. This is mainly because they are highly toxic. They are also known to be bio accumulative and non-biodegradable. Lead for example, has been linked to a number of health problems which include damage of vital internal body systems like the nervous and reproductive system as well as the kidneys. From this background therefore, the removal of the toxic heavy metal, Pb2+ from waste water was investigated using nano silica hollow spheres (NSHS) as the adsorbent. Synthesis of NSHS was done using a three-stage process in which CaCO3 nanoparticles were initially prepared as a template. This was followed by treatment of the formed oxide particles with NaSiO3 to give a nanocomposite. Finally, the template was destroyed using 2.0M HCl to give NSHS. Characterization of the nanoparticles was done using analytical techniques like XRD, SEM, and TGA. For the adsorption process, both thermodynamic and equilibrium studies were carried out. Thermodynamic studies were carried out and the Gibbs free energy, Enthalpy and Entropy of the adsorption process were determined. The results revealed that the adsorption process was both endothermic and spontaneous. Equilibrium studies were also carried out in which the Langmuir and Freundlich isotherms were tested. The results showed that the Langmuir model best described the adsorption equilibrium.

Keywords: characterization, endothermic, equilibrium studies, Freundlich, Langmuir, nanoparticles, thermodynamic studies

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5061 Study of the Influence of Hole Topology on Crack Propagation Rate

Authors: Hallan Moura Ladeira, Carla Tatiana Mota Anflor

Abstract:

The drilling process for bolted or riveted joints of components is very common in the naval, aeronautical, mechanical, and civil industries. In this context, the present work aims to study, through computer simulation, the influence of hole geometry (through, chamfered, and rounded) on crack propagation when submitted to static and dynamic loads. For the static crack evaluation, failure was considered when the stress intensity factor (FIT) exceeds the fracture toughness of the material (KIc). In the case of fatigue, the condition of the small crack tip plastification zone and the Paris Law were considered for determining region II of the dadN x ΔK curve. Initially, a parametric analysis of the hole geometry was performed to obtain a topology that would result in less discontinuity of the stress field and, consequently, less influence on static crack growth. The best performing topology was then used to study the fatigue crack growth rate considering the Paris Law. The numerical tests were performed on a 7075-T6 aluminum specimen resulting in dadN x ΔK curves in good agreement with the literature.

Keywords: holes, cracks, loading, fracture toughness

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5060 Technological Development of a Biostimulant Bioproduct for Fruit Seedlings: An Engineering Overview

Authors: Andres Diaz Garcia

Abstract:

The successful technological development of any bioproduct, including those of the biostimulant type, requires to adequately completion of a series of stages allied to different disciplines that are related to microbiological, engineering, pharmaceutical chemistry, legal and market components, among others. Engineering as a discipline has a key contribution in different aspects of fermentation processes such as the design and optimization of culture media, the standardization of operating conditions within the bioreactor and the scaling of the production process of the active ingredient that it will be used in unit operations downstream. However, all aspects mentioned must take into account many biological factors of the microorganism such as the growth rate, the level of assimilation to various organic and inorganic sources and the mechanisms of action associated with its biological activity. This paper focuses on the practical experience within the Colombian Corporation for Agricultural Research (Agrosavia), which led to the development of a biostimulant bioproduct based on native rhizobacteria Bacillus amyloliquefaciens, oriented mainly to plant growth promotion in cape gooseberry nurseries and fruit crops in Colombia, and the challenges that were overcome from the expertise in the area of engineering. Through the application of strategies and engineering tools, a culture medium was optimized to obtain concentrations higher than 1E09 CFU (colony form units)/ml in liquid fermentation, the process of biomass production was standardized and a scale-up strategy was generated based on geometric (H/D of bioreactor relationships), and operational criteria based on a minimum dissolved oxygen concentration and that took into account the differences in the capacity of control of the process in the laboratory and pilot scales. Currently, the bioproduct obtained through this technological process is in stages of registration in Colombia for cape gooseberry fruits for export.

Keywords: biochemical engineering, liquid fermentation, plant growth promoting, scale-up process

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5059 The Role of Macroeconomic Condition and Volatility in Credit Risk: An Empirical Analysis of Credit Default Swap Index Spread on Structural Models in U.S. Market during Post-Crisis Period

Authors: Xu Wang

Abstract:

This research builds linear regressions of U.S. macroeconomic condition and volatility measures in the investment grade and high yield Credit Default Swap index spreads using monthly data from March 2009 to July 2016, to study the relationship between different dimensions of macroeconomy and overall credit risk quality. The most significant contribution of this research is systematically examining individual and joint effects of macroeconomic condition and volatility on CDX spreads by including macroeconomic time series that captures different dimensions of the U.S. economy. The industrial production index growth, non-farm payroll growth, consumer price index growth, 3-month treasury rate and consumer sentiment are introduced to capture the condition of real economic activity, employment, inflation, monetary policy and risk aversion respectively. The conditional variance of the macroeconomic series is constructed using ARMA-GARCH model and is used to measure macroeconomic volatility. The linear regression model is conducted to capture relationships between monthly average CDX spreads and macroeconomic variables. The Newey–West estimator is used to control for autocorrelation and heteroskedasticity in error terms. Furthermore, the sensitivity factor analysis and standardized coefficients analysis are conducted to compare the sensitivity of CDX spreads to different macroeconomic variables and to compare relative effects of macroeconomic condition versus macroeconomic uncertainty respectively. This research shows that macroeconomic condition can have a negative effect on CDX spread while macroeconomic volatility has a positive effect on determining CDX spread. Macroeconomic condition and volatility variables can jointly explain more than 70% of the whole variation of the CDX spread. In addition, sensitivity factor analysis shows that the CDX spread is the most sensitive to Consumer Sentiment index. Finally, the standardized coefficients analysis shows that both macroeconomic condition and volatility variables are important in determining CDX spread but macroeconomic condition category of variables have more relative importance in determining CDX spread than macroeconomic volatility category of variables. This research shows that the CDX spread can reflect the individual and joint effects of macroeconomic condition and volatility, which suggests that individual investors or government should carefully regard CDX spread as a measure of overall credit risk because the CDX spread is influenced by macroeconomy. In addition, the significance of macroeconomic condition and volatility variables, such as Non-farm Payroll growth rate and Industrial Production Index growth volatility suggests that the government, should pay more attention to the overall credit quality in the market when macroecnomy is low or volatile.

Keywords: autoregressive moving average model, credit spread puzzle, credit default swap spread, generalized autoregressive conditional heteroskedasticity model, macroeconomic conditions, macroeconomic uncertainty

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5058 Education of Mothers and Influence on the Development of Intrauterine Growth Restriction

Authors: Sabina Garayeva

Abstract:

To determine the significant risk factors for intrauterine growth restriction (IUGR), we carried out a thorough study of the social status of the parents of children with IUGR. We observed 315 mothers who gave birth to children with (IUGR), of which 172 mothers with asymmetric type and 143 mothers with symmetric type of IUGR. Through a detailed survey was gathered detailed information about education of parents. The results show that the majority of mothers with IUGR had secondary education (44,8 ± 2,8%), and fathers - higher education (35,2 ± 2,7%). Whereas in the control group, the largest number of parents had higher education (mother 35,3 ± 4,4%, fathers 42,9 ± 4,5%). Number of mothers with secondary education with IUGR was significantly (p1 <0,01; χ2 = 22,67) differs from the number of mothers with physiological pregnancy with the same level of education. Meanwhile, in the group with a symmetrical embodiment of IUGR mothers with secondary formation of significantly greater 53,1 ± 4,2%, than the asymmetric embodiment IUGR 37,8 ± 3,7% (p2 <0,05; χ2 = 8 06). Among fathers with secondary education significant difference was noted in the symmetric version of IUGR 37,8 ± 4,1% more than in the control group (p1 <0,05), and among parents of children with asymmetric IUGR option prevailed fathers with higher education - 37 2 ± 3,7%. Thus, our results revealed a low educational level of the mother as a risk factor for IUGR, which further help to develop preventive and therapeutic measures to eliminate the severity of its consequences. As seen from the data presented, mothers of children with asymmetric IUGR had a school education and fathers - higher education, while in the symmetric type of both parents had secondary education. It is found that frequency of children, born with IUGR, of mothers - housewives and fathers, engage in physical labor, was high. Thus, the analysis conducted by the social status of the parents with IUGR revealed a low level of education and unemployed mothers as risk factors for this disease, which in the future will help to develop preventive and therapeutic measures to eliminate the severity of its.

Keywords: intrauterine growth restriction, education of mothers, education influence, IUGR

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5057 2D CFD-PBM Coupled Model of Particle Growth in an Industrial Gas Phase Fluidized Bed Polymerization Reactor

Authors: H. Kazemi Esfeh, V. Akbari, M. Ehdaei, T. N. G. Borhani, A. Shamiri, M. Najafi

Abstract:

In an industrial fluidized bed polymerization reactor, particle size distribution (PSD) plays a significant role in the reactor efficiency evaluation. The computational fluid dynamic (CFD) models coupled with population balance equation (CFD-PBM) have been extensively employed to investigate the flow behavior in the poly-disperse multiphase fluidized bed reactors (FBRs) utilizing ANSYS Fluent code. In this study, an existing CFD-PBM/ DQMOM coupled modeling framework has been used to highlight its potential to analyze the industrial-scale gas phase polymerization reactor. The predicted results reveal an acceptable agreement with the observed industrial data in terms of pressure drop and bed height. The simulated results also indicate that the higher particle growth rate can be achieved for bigger particles. Hence, the 2D CFD-PBM/DQMOM coupled model can be used as a reliable tool for analyzing and improving the design and operation of the gas phase polymerization FBRs.

Keywords: computational fluid dynamics, population balance equation, fluidized bed polymerization reactor, direct quadrature method of moments

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5056 Design and Construction Demeanor of a Very High Embankment Using Geosynthetics

Authors: Mariya Dayana, Budhmal Jain

Abstract:

Kannur International Airport Ltd. (KIAL) is a new Greenfield airport project with airside development on an undulating terrain with an average height of 90m above Mean Sea Level (MSL) and a maximum height of 142m. To accommodate the desired Runway length and Runway End Safety Area (RESA) at both the ends along the proposed alignment, it resulted in 45.5 million cubic meters in cutting and filling. The insufficient availability of land for the construction of free slope embankment at RESA 07 end resulted in the design and construction of Reinforced Soil Slope (RSS) with a maximum slope of 65 degrees. An embankment fill of average 70m height with steep slopes located in high rainfall area is a unique feature of this project. The design and construction was challenging being asymmetrical with curves and bends. The fill was reinforced with high strength Uniaxial geogrids laid perpendicular to the slope. Weld mesh wrapped with coir mat acted as the facia units to protect it against surface failure. Face anchorage were also provided by wrapping the geogrids along the facia units where the slope angle was steeper than 45 degrees. Considering high rainfall received on this table top airport site, extensive drainage system was designed for the high embankment fill. Gabion wall up to 10m height were also designed and constructed along the boundary to accommodate the toe of the RSS fill beside the jeepable track at the base level. The design of RSS fill was done using ReSSA software and verified in PLAXIS 2D modeling. Both slip surface failure and wedge failure cases were considered in static and seismic analysis for local and global failure cases. The site won excavated laterite soil was used as the fill material for the construction. Extensive field and laboratory tests were conducted during the construction of RSS system for quality assurance. This paper represents a case study detailing the design and construction of a very high embankment using geosynthetics for the provision of Runway length and RESA area.

Keywords: airport, embankment, gabion, high strength uniaxial geogrid, kial, laterite soil, plaxis 2d

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5055 Analysis of Causality between Economic Growth and Carbon Emissions: The Case of Mexico 1971-2011

Authors: Mario Gómez, José Carlos Rodríguez

Abstract:

This paper analyzes the Environmental Kuznets Curve (EKC) hypothesis to test the causality relationship between economic activity, trade openness and carbon dioxide emissions in Mexico (1971-2011). The results achieved in this research show that there are three long-run relationships between production, trade openness, energy consumption and carbon dioxide emissions. The EKC hypothesis was not verified in this research. Indeed, it was found evidence of a short-term unidirectional causality from GDP and GDP squared to carbon dioxide emissions, from GDP, GDP squared and TO to EC, and bidirectional causality between TO and GDP. Finally, it was found evidence of long-term unidirectional causality from all variables to carbon emissions. These results suggest that a reduction in energy consumption, economic activity, or an increase in trade openness would reduce pollution.

Keywords: causality, cointegration, energy consumption, economic growth, environmental Kuznets curve

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5054 Intensive Multidisciplinary Feeding Intervention for a Toddler with In-Utero Drug Exposure

Authors: Leandra Prempeh, Emily Malugen

Abstract:

Prenatal drug exposure can have a molecular impact on the hypothalamic and reward genes that regulate feeding behavior. This can impact feeding regulation, resulting in feeding difficulties and growth failure. This was potentially seen in “McKayla,” a 19- month old girl with a history of in-utero drug exposure, patent ductus arteriosus, and gastroesophageal reflux disease who presented for intensive day treatment feeding therapy. She was diagnosed with Avoidant Restrictive Food Intake Disorder, described as total food refusal and meeting 100% of her caloric needs from a gastrostomy tube. The primary goals during intensive feeding therapy were to increase her oral intake and decrease her reliance on supplementation with formula. Several behavioral antecedent manipulations were implemented to establish consistent responding and make progress towards treatment goals. This included multiple modified bolus placements (using underloaded and Nuk brush), reinforcement contingencies, and variety fading before stability was finally achieved. Following, increasing retention of bites then increasing volume and variety were goals targeted. From treatment onset to the last 3 days of treatment, McKayla's rate of rapid acceptance of bite presentations increased significantly from 33.33% to 93.13%, rapid swallowing went from 0.00% to 92.32%, and her percentage of inappropriate mealtime behavior and expels decreased from 58.33% and 100% to 2.31% and 7.68%, respectively. Overall, the treatment team successfully introduced and increased the bite size of 7 pureed foods, generalize the treatment to caregivers with high integrity, and began facilitating tube weaning. She was receiving about 33.42% of her needs by mouth at the time of discharge. Other nutritional concerns addressed during treatment included drinking a nutritionally complete drink out of an open cup and age appropriate growth. McKayla continued to have emesis almost daily, as was her baseline before starting treatment; however, the frequency during mealtime decreased. Overall, McKayla responded well to treatment. She had a very slow response to treatment and required a lot of antecedent manipulations to establish consistent responding. As the literature suggests, [drug]-exposed neonates, like McKayla, may be at increased risk for nutritional and growth challenges that may persist throughout development. This supports the need for longterm follow-up of infant growth.

Keywords: behavioral intervention, feeding problems, in-utero drug exposure, intensive multidisciplinary intervention

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5053 Potential of Enhancing Oil Recovery in Omani Oil Fields via Biopolymer Injection

Authors: Yahya Al-Wahaibi, Saif Al-Bahry, Abdulkadir Elshafie, Ali Al-Bemani, Sanket Joshi

Abstract:

Microbial enhanced oil recovery is one of the most economical and efficient methods for extending the life of production wells in a declining reservoir. There are a variety of metabolites produced by microorganisms that can be useful for oil recovery, like biopolymers-polysaccharides secreted by microbes, biodegradable thus environmentally friendly. Some fungi like Schizophyllum commune (a type of mushroom), and Aureobasidium pullulans are reported to produce biopolymers-schizophyllan and pullulan. Hence, we have procured a microbial strain (Schizophyllum commune) from American Type Culture Collection, which is reported for producing a biopolymer and also isolated several Omani strains of Aureobasidium pullulans from different samples. Studies were carried out for maintenance of the strains and primary screening of production media and environmental conditions for growth of S. commune and Omani A. pullulans isolates, for 30 days. The observed optimum growth and production temperature was ≤35 °C for S. commune and Omani A. pullulans isolates. Better growth was observed for both types of fungi under shaking conditions. The initial yield of lyophilized schizophyllan was ≥3.0 g/L, and the yield of pullulan was ≥0.5g/L. Both schizophyllan and pullulan were extracted in crude form and were partially identified by Fourier transform infrared spectroscopy (FTIR), which showed partial similarity in chemical structure with published biopolymers. The produced pullulan and schizophyllan increased the viscosity from 9-20 cp of the control media (without biopolymer) to 20 - 121.4 cp of the cell free broth at 0.1 s-1 shear rate at range of temperatures from 25–45 °C. Enhanced biopolymer production and its physicochemical and rheological properties under different environmental conditions (different temperatures, salt concentrations and wide range of pH), complete characterization and effects on oil recovery enhancement were also investigated in this study.

Keywords: Aureobasidium pullulans, biopolymer, oil recovery enhancement, Schizophyllum commune

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5052 As Evolved Mechanisms and Cultural Modeling Affect Child Gender Attribution

Authors: Stefano Federici, Alessandro Lepri, Antonella Carrera

Abstract:

Kessler and McKenna in the seventies, and recently Federici and Lepri investigated how an individual attributes gender to a person. By administering nudes of human figures, the scholars have found that the penis more than the vagina and the male sexual characteristics more than the female ones are significantly more salient in the gender attribution process. Federici and Lepri suggested that the asymmetrical salience of sexual characteristics is attributable to evolved decision-making processes for the solution of gender attribution problems to avoid the greatest danger of an (angry) adult male. The present study has observed the behaviour of 60 children, aged between 3 and 6 years, and their parents verifying whether the child gender attribution mechanisms are permeable to cultural stereotypes. The participating children were asked to make a male or a female on a tablet by combining 12 human physical characteristics (long hair, short hair, wide hips, narrow hips, breasts, flat chest, body hair, hairless body, penis, vagina, male face, and female face) and four cloths (male t-shirt, female t-shirt, pants, and skirt) by superimposing one or more of them on a sexually neutral manikin. On the tablet was installed an App, created by authors, to replicate the Kessler and McKenna and Federici and Lepri previous studies. One of the parents of each of the participating children was asked to make a male or a female using the same apparatus used by children. In addition, the participating parents were asked to complete a test, as proposed by Federici and Lepri in their previous study, to compare adult and child processes of gender attribution. The results suggested that children are affected both by evolved mechanisms as adults were (e.g., taking less time to make a male than a female, using the penis more often than the vagina), and by cultural modeling of parental and environmental gender stereotypes (e.g., the genitals were often covered with pants in case the delivery was to make a male and a skirt in the case was to make a female).

Keywords: biological sex, cognitive biases, cultural modeling, gender attribution, evolved decision-making processes

Procedia PDF Downloads 108
5051 Supplementation of Yeast Cell Wall on Growth Performance in Broiler Reared under High Ambient Temperature

Authors: Muhammad Shahzad Hussain

Abstract:

Two major problems are facing generally by conventional poultry farming that is disease outbreaks and poor performance, which results due to improper management. To enhance the growth performance and efficiency of feed and reduce disease outbreaks, antibiotic growth promoters (AGPs) which are antibiotics at sub-therapeutic levels, are extensively used in the poultry industry. European Union has banned the use of antibiotics due to their presence in poultry products, development of antibiotic-resistant pathogens, and disturbance of normal gut microbial ecology. These residues cause serious health concerns and produce antibiotic resistance in pathogenic microbes in human beings. These issues strengthen the need for the withdrawal of AGPs from poultry feed. Nowadays, global warming is a major issue, and it is more critical in tropical areas like Pakistan, where heat stress is already a major problem. Heat stress leads to poor production performance, high mortality, immuno-suppression, and concomitant diseases outbreak. The poultry feed industry in Pakistan, like other countries of the world, has been facing shortages and high prices of local as well as imported feed ingredients. Prebiotics are potential replacer for AGP as prebiotics has properties to enhance the production potential and reduce the growth of harmful bacteria as well as stimulate the growth/activity of beneficial bacteria. The most commonly used prebiotics in poultry includes mannan oligosaccharide (MOS). MOS is an essential component of the yeast cell wall (YCW) (Saccharomyces cerevisiae); therefore, the YCW wall possesses prebiotic properties. The use of distillery yeast wall (YCW) has the potential to replace conventional AGPs and to reduce mortality due to heat stress as well as to bind toxins in the feed. The dietary addition of YCW has not only positive effects on production performance in poultry during normal conditions but during stressful conditions. A total of 168-day-old broilers were divided into 6 groups, each of which has 28 birds with 4 replicates (n=7).Yeast cell wall (YCW) supplementation @ 0%, 1%, 1.5%, 2%, 2.5%, 3% from day 0 to 35. Heat stress was exposed from day 21 to 35 at 30±1.1ᵒC with relative humidity 65±5%. Zootechnical parameters like body weight, FCR, Organ development, and histomorphometric parameters were studied. A significant weight gain was observed at group C supplemented @ 1.5% YCW during the fifth week. Significant organ weight gain of Gizzard, spleen, small intestine, and cecum was observed at group C supplemented @ 1.5% YCW. According to morphometric indices Duodenum, Jejunum, and Ileum has significant villus height, while Jejunum and Ileum have also significant villus surface area in the group supplemented with 1.5% YCW. IEL count was only decreased in 1.5% YCW-fed group in jejunum and ileum, not in duodenum, that was less in 2% YCW-supplemented group. Dietary yeast cell wall of saccharomyces cerevisiae partially reduced the effects of high ambient temperature in terms of better growth and modified gut histology and components of mucosal immune response to better withstand heat stress in broilers.

Keywords: antibiotics, AGPs, broilers, MOS, prebiotics, YCW

Procedia PDF Downloads 68
5050 Effect of Rotation Rate on Chemical Segregation during Phase Change

Authors: Nouri Sabrina, Benzeghiba Mohamed, Ghezal Abderrahmane

Abstract:

Numerical parametric study is conducted to study the effects of ampoule rotation on the flows and the dopant segregation in vertical Bridgman (VB) crystal growth. Calculations were performed in unsteady state. The extended Darcy model, which includes the time derivative and Coriolis terms, has been employed in the momentum equation. It was found that the convection, and dopant segregation can be affected significantly by ampoule rotation, and the effect is similar to that by an axial magnetic field. Ampoule rotation decreases the intensity of convection and stretches the flow cell axially. When the convection is weak, the flow can be suppressed almost completely by moderate ampoule rotation and the dopant segregation becomes diffusion-controlled. For stronger convection, the elongated flow cell by ampoule rotation may bring dopant mixing into the bulk melt reducing axial segregation at the early stage of the growth. However, if the cellular flow cannot be suppressed completely, ampoule rotation may induce larger radial segregation due to poor mixing.

Keywords: numerical simulation, heat and mass transfer, vertical solidification, chemical segregation

Procedia PDF Downloads 331
5049 Evaluation of in vitro Inhibitory Effect of Enoxacin on Babesia and Theileria Parasites

Authors: Mosaab A. Omar, Mohammad Saleh Al-Aboody, Mohmed A. Rizk, Shimaa M. Elsayed, Ahmed ElSify, Naoaki Yokoyama, Ikuo Igarashi

Abstract:

Enoxacin is a broad-spectrum 6-fluoronaphthyridinone antibacterial agent (fluoroquinolones) structurally related to nalidixic acid used mainly in the treatment of urinary tract infections and gonorrhea. Also, it has been shown recently that it may have cancer inhibiting effect. The primary antibabesial effect of Enoxacin is due to inhibition of DNA gyrase subunit A, and DNA topoisomerase. In the present study, enoxacin was tested as a potent inhibitor against the in vitro growth of bovine and equine Piroplasms. The in vitro growth of five Babesia species that were tested was significantly inhibited (P<0.05) by micromolar concentrations of enoxacin (IC50 values= 13.5, 7.2, 7.5, and 24.2 µM for Babesia bovis, Babesia bigemina, Babesia caballi, and Theileria equi, respectively). Enoxacin IC50 values for Babesia and Theileria parasites were satisfactory as the drug is a potent antibacterial drug with minimum side effects. Therefore, enoxacin might be used for the treatment of Babesiosis and Theileriosis especially in case of mixed infections with bacterial diseases or in the case of animal sensitivity against diminazin toxicity.

Keywords: enoxacin, Babesia, Theileria, IC50 and dimenazin

Procedia PDF Downloads 448
5048 Fracture Toughness Characterizations of Single Edge Notch (SENB) Testing Using DIC System

Authors: Amr Mohamadien, Ali Imanpour, Sylvester Agbo, Nader Yoosef-Ghodsi, Samer Adeeb

Abstract:

The fracture toughness resistance curve (e.g., J-R curve and crack tip opening displacement (CTOD) or δ-R curve) is important in facilitating strain-based design and integrity assessment of oil and gas pipelines. This paper aims to present laboratory experimental data to characterize the fracture behavior of pipeline steel. The influential parameters associated with the fracture of API 5L X52 pipeline steel, including different initial crack sizes, were experimentally investigated for a single notch edge bend (SENB). A total of 9 small-scale specimens with different crack length to specimen depth ratios were conducted and tested using single edge notch bending (SENB). ASTM E1820 and BS7448 provide testing procedures to construct the fracture resistance curve (Load-CTOD, CTOD-R, or J-R) from test results. However, these procedures are limited by standard specimens’ dimensions, displacement gauges, and calibration curves. To overcome these limitations, this paper presents the use of small-scale specimens and a 3D-digital image correlation (DIC) system to extract the parameters required for fracture toughness estimation. Fracture resistance curve parameters in terms of crack mouth open displacement (CMOD), crack tip opening displacement (CTOD), and crack growth length (∆a) were carried out from test results by utilizing the DIC system, and an improved regression fitting resistance function (CTOD Vs. crack growth), or (J-integral Vs. crack growth) that is dependent on a variety of initial crack sizes was constructed and presented. The obtained results were compared to the available results of the classical physical measurement techniques, and acceptable matchings were observed. Moreover, a case study was implemented to estimate the maximum strain value that initiates the stable crack growth. This might be of interest to developing more accurate strain-based damage models. The results of laboratory testing in this study offer a valuable database to develop and validate damage models that are able to predict crack propagation of pipeline steel, accounting for the influential parameters associated with fracture toughness.

Keywords: fracture toughness, crack propagation in pipeline steels, CTOD-R, strain-based damage model

Procedia PDF Downloads 46
5047 Assessing Denitrification-Disintegration Model’s Efficacy in Simulating Greenhouse Gas Emissions, Crop Growth, Yield, and Soil Biochemical Processes in Moroccan Context

Authors: Mohamed Boullouz, Mohamed Louay Metougui

Abstract:

Accurate modeling of greenhouse gas (GHG) emissions, crop growth, soil productivity, and biochemical processes is crucial considering escalating global concerns about climate change and the urgent need to improve agricultural sustainability. The application of the denitrification-disintegration (DNDC) model in the context of Morocco's unique agro-climate is thoroughly investigated in this study. Our main research hypothesis is that the DNDC model offers an effective and powerful tool for precisely simulating a wide range of significant parameters, including greenhouse gas emissions, crop growth, yield potential, and complex soil biogeochemical processes, all consistent with the intricate features of environmental Moroccan agriculture. In order to verify these hypotheses, a vast amount of field data covering Morocco's various agricultural regions and encompassing a range of soil types, climatic factors, and crop varieties had to be gathered. These experimental data sets will serve as the foundation for careful model calibration and subsequent validation, ensuring the accuracy of simulation results. In conclusion, the prospective research findings add to the global conversation on climate-resilient agricultural practices while encouraging the promotion of sustainable agricultural models in Morocco. A policy architect's and an agricultural actor's ability to make informed decisions that not only advance food security but also environmental stability may be strengthened by the impending recognition of the DNDC model as a potent simulation tool tailored to Moroccan conditions.

Keywords: greenhouse gas emissions, DNDC model, sustainable agriculture, Moroccan cropping systems

Procedia PDF Downloads 47
5046 Formulation and Characterization of NaCS-PDMDAAC Capsules with Immobilized Chlorella vulgaris for Phycoremediation of Palm Oil Mill Effluent

Authors: Quin Emparan, Razif Harun, Dayang R. A. Biak, Rozita Omar, Michael K. Danquah

Abstract:

Cultivation of immobilized microalgae cells is on the rise for biotechnological applications. In this study, cultivation of Chlorella vulgaris was carried out in the form of suspended free-cell and immobilized cells system. NaCS-PDMDAAC capsules were used to immobilize C. vulgaris. Initially, the synthesized NaCS with C. vulgaris culture were prepared at various concentration of 5- 20% (w/v) using a 6% hardening solution (PDMDAAC) to investigate the capsules' gel stability and suitability for microalgae cells growth. Then, the capsules produced from 15% NaCS with C. vulgaris culture were furthered investigated using 5%, 10%, and 15% (w/v) of PDMDAAC solution. The capsules' gel stability was evaluated through dissolution time and loss of uniform spherical shape of capsules, while suitability for microalgae cells growth was evaluated through the optical density of microalgae. In this study, the 15% NaCS-10% PDMDAAC capsules were found to be the most suitable to sustain the capsules' gel stability and microalgae cells growth in MLA. For that reason, the C. vulgaris immobilized in the 15% NaCS-10% PDMDAAC capsules were further characterized using physicochemical analysis in terms of morphological, carbon (C), hydrogen (H) and nitrogen (N), Fourier transform-infrared (FT-IR), scanning electron microscopy-energy dispersive X-ray (SEM-EDX), zeta potential and Brunauer-Emmet-Teller (BET) analyses. The results revealed that the presence of sulfonates in the synthesized NaCS and NaCS-PDMDAAC capsules without and with C. vulgaris proves that cellulose alcohol group was successfully bonded by sulfo group. Besides that, immobilized microalgae cells have a smaller cell size of 6.29 ± 1.09 µm and zeta potential of -11.93 ± 0.91 mV than suspended free-cells microalgae culture. It can be summarized that immobilization of C. vulgaris in the 15% NaCS-10% PDMDAAC capsules are relevant as a bioremediator for wastewater treatment purposes due to its suitable size of pore and capsules as well as structural and compositional properties.

Keywords: biological capsules, immobilized cultivation, microalgae, physico-chemical analysis

Procedia PDF Downloads 147
5045 Effect of Cryogenic Pre-stretching on the Room Temperature Tensile Behavior of AZ61 Magnesium Alloy and Dominant Grain Growth Mechanisms During Subsequent Annealing

Authors: Umer Masood Chaudry, Hafiz Muhammad Rehan Tariq, Chung-soo Kim, Tea-sung Jun

Abstract:

This study explored the influence of pre-stretching temperature on the microstructural characteristics and deformation behavior of AZ61 magnesium alloy and its implications on grain growth during subsequent annealing. AZ61 alloy was stretched to 5% plastic strain along rolling (RD) and transverse direction (TD) at room (RT) and cryogenic temperature (-150 oC, CT) followed by annealing at 320 oC for 1 h to investigate the twinning and dislocation evolution and its consequent effect on the flow stress, plastic strain and strain hardening rate. Compared to RT-stretched samples, significant improvement in yield stress, strain hardening rate and moderate reduction in elongation to failure were witnessed for CT-stretched samples along RD and TD. The subsequent EBSD analysis revealed the increased fraction of fine {10-12} twins and nucleation of multiple {10-12} twin variants caused by higher local stress concentration at the grain boundaries in CT-stretched samples as manifested by the kernel average misorientation. This higher twin fraction and twin-twin interaction imposed the strengthening by restricting the mean free path of dislocations, leading to higher flow stress and strain hardening rate. During annealing of the RT/CT-stretched samples, the residual strain energy and twin boundaries were decreased due to static recovery, leading to a coarse-grained twin-free microstructure. Strain induced boundary migration (SBIM) was found to be the predominant mechanism governing the grain growth during annealing via movement of high angle grain boundaries.

Keywords: magnesium, twinning, twinning variant selection, EBSD, cryogenic deformation

Procedia PDF Downloads 51
5044 Socio-Economic and Environmental Impact of Urban Sprawl: A Case Study Adigrat City, Tigray, Ethiopia

Authors: Fikre Belay Tekulu

Abstract:

This thesis presents the socio-economic and environmental impacts of urban sprawl in the case of Adigrat city, Tigray Region, Ethiopia. The main objective of this research is to assess major causes, trends and socio-economic and environmental impacts of the urban sprawl of Adigrat city. The study employed both quantitative and qualitative methods as questionnaires, interviews and observation used for data collection. Simple random sampling has been used to select the participants. The land use and land cover change for agricultural land and forest and grassland resource analysis is done with the aid of GIS. Urban sprawl is mainly caused by the rapid population growth, increase in the living and property cost in the core of the city, land demand and land speculation and the growth of transport and an increase in income of people and demand of more living space. The study indicates 15726.24 hectares (515.49 per cent) of new land added to the city jurisdiction from its adjacent Gantafeshum Wereda between 1986 and 2018. The population of Adigrat city increased by 9.045 per cent per year, while the city expanded 16.01 per cent per annum and the LCR was 0.0233 hectares per person between 1986 and 2018.Built-up area increased by 35.27 per cent per annum, while agricultural land, forests and grassland cover decreased by 1.68 per cent and 1.26 per cent per annum respectively in the last thirty three years. This rapid growth of urban sprawl brought social-economic and environmental change in the city that has been observed by the city residents. Therefore, the city administration should need strong, integrated, effective and efficient work, with its neighbor rural area and also done timely preparation, implementation, supervision, and evaluation of the structural plan of the city to bring out sustainable development of the city.

Keywords: cause, , trends, urban sprawl, land use land cover, GIS

Procedia PDF Downloads 112
5043 Mugil cephalus Presents a Feasible Alternative To Lates calcarifer Farming in Brackishwater: Evidence From Grey Mullet Mugil Cephalus Farming in Bangladesh

Authors: Asif Hasan

Abstract:

Among the reported suitable mariculture species in Bangladesh, seabass and mullet are the two most popular candidates due to their high market values. Several field studies conducted on the culture of seabass in Bangladesh, it still remains a challenge to commercially grow this species due to its exclusive carnivorous nature. In contrast, the grey mullet (M. cephalus) is a fast-growing, omnivorous euryhaline fish that has shown excellent growth in many areas including South Asia. Choice of a sustainable aquaculture technique must consider the productivity and yield as well as their environmental suitability. This study was designed to elucidate the ecologically suitable culture technique of M. cephalus in brakishwater ponds by comparing the biotic and abiotic components of pond ecosystem. In addition to growth parameters (yield, ADG, SGR, weight gain, FCR), Physicochemical parameters (Temperature, DO, pH, salinity, TDS, transparency, ammonia, and Chlorophyll-a concentration) and biological community composition (phytoplankton, zooplankton and benthic macroinvertebrates) were investigated from ponds under Semi-intensive, Improve extensive and Traditional culture system. While temperature were similar in the three culture types, ponds under improve-extensive showed better environmental conditions with significantly higher mean DO and transparency, and lower TDS and Chlorophyll-a. The abundance of zooplankton, phytoplankton and benthic macroinvertebrates were apparently higher in semi-intensive ponds. The Analysis of Similarity (ANOSIM) suggested moderate difference in the planktonic community composition. While the fish growth parameters of M. cephalus and total yield did not differ significantly between three systems, M. cephalus yield (kg/decimal) was apparently higher in semi-intensive pond due to high stocking density and intensive feeding. The results suggested that the difference between the three systems were due to more efficient utilization of nutrients in improve extensive ponds which affected fish growth through trophic cascades. This study suggested that different culture system of M. cephalus is an alternative and more beneficial method owing to its ecological and economic benefits in brackishwater ponds.

Keywords: Mugil cephalus, pond ecosystem, mariculture, fisheries management

Procedia PDF Downloads 40
5042 Experimental Investigation of Heat Transfer and Scale Growth Characteristics of Crystallisation Scale in Agitation Tank

Authors: Prasanjit Das, M .M. K. Khan, M. G. Rasul, Jie Wu, I. Youn

Abstract:

Crystallisation scale occurs when dissolved minerals precipitate from an aqueous solution. To investigate the crystallisation scale growth of normal solubility salt, a lab-scale agitation tank with and without baffles were used as a benchmark using potassium nitrate as the test fluid. Potassium nitrate (KNO3) solution in this test leads to crystallisation scale on heat transfer surfaces. This experimental investigation has focused on the effect of surface crystallisation of potassium nitrate on the low-temperature heat exchange surfaces on the wall of the agitation tank. The impeller agitation rate affects the scaling rate at the low-temperature agitation wall and it shows a decreasing scaling rate with an increasing agitation rate. It was observed that there was a significant variation of heat transfer coefficients and scaling resistance coefficients with different agitation rate as well as with varying impeller size, tank with and without baffles and solution concentration.

Keywords: crystallisation, heat transfer coefficient, scale, resistance

Procedia PDF Downloads 166