Search results for: African sharp tooth cat fish
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 2437

Search results for: African sharp tooth cat fish

1447 Harnessing Environmental DNA to Assess the Environmental Sustainability of Commercial Shellfish Aquaculture in the Pacific Northwest United States

Authors: James Kralj

Abstract:

Commercial shellfish aquaculture makes significant contributions to the economy and culture of the Pacific Northwest United States. The industry faces intense pressure to minimize environmental impacts as a result of Federal policies like the Magnuson-Stevens Fisheries Conservation and Management Act and the Endangered Species Act. These policies demand the protection of essential fish habitat and declare several salmon species as endangered. Consequently, numerous projects related to the protection and rehabilitation of eelgrass beds, a crucial ecosystem for countless fish species, have been proposed at both state and federal levels. Both eelgrass beds and commercial shellfish farms occupy the same physical space, and therefore understanding the effects of shellfish aquaculture on eelgrass ecosystems has become a top ecological and economic priority of both government and industry. This study evaluates the organismal communities that eelgrass and oyster aquaculture habitats support. Water samples were collected from Willapa Bay, Washington; Tillamook Bay, Oregon; Humboldt Bay, California; and Sammish Bay, Washington to compare species diversity in eelgrass beds, oyster aquaculture plots, and boundary edges between these two habitats. Diversity was assessed using a novel technique: environmental DNA (eDNA). All organisms constantly shed small pieces of DNA into their surrounding environment through the loss of skin, hair, tissues, and waste. In the marine environment, this DNA becomes suspended in the water column allowing it to be easily collected. Once extracted and sequenced, this eDNA can be used to paint a picture of all the organisms that live in a particular habitat making it a powerful technology for environmental monitoring. Industry professionals and government officials should consider these findings to better inform future policies regulating eelgrass beds and oyster aquaculture. Furthermore, the information collected in this study may be used to improve the environmental sustainability of commercial shellfish aquaculture while simultaneously enhancing its growth and profitability in the face of ever-changing political and ecological landscapes.

Keywords: aquaculture, environmental DNA, shellfish, sustainability

Procedia PDF Downloads 245
1446 Physicochemical Properties of Low Viscosity Banana Juice

Authors: Victor Vicent, Oscar Kibazohi

Abstract:

Banana (Musa acuminata) is one of the most largely consumed fruits in the world. It is an excellent source of potassium, antioxidants, and fiber. In East and Central African countries, banana is used to produce low viscosity clear juice using traditional kneading of ripe banana and grasses until juice oozes out. Recently, an improved method involving blending of the banana followed by pressing to separate the juice from pulp has been achieved. This study assessed the physicochemical properties of banana juice prior to product formulation. Two different banana juices from two cultivars: Pisang awak and Mbile an East African Highland Banana (EAHB) were evaluated for viscosity, sugars (sucrose, fructose, and glucose), organic acids (malic, citric and succinic acids) and minerals using the HPLC and AAS. Juice extracted from Pisang awak had a viscosity of 3.43 × 10⁻⁵ N.m⁻² s while EAHB juice had a viscosity of 6.02 × 10⁻⁵ N.m⁻² s. Sugar concentrations varied with banana place of origin. Pisang awak juice had a higher dissolved solids value of 24-28ᵒ Brix then EAHB, whose value was 18-24ᵒ Brix. Juice viscosity was 3.5–5.3 mPa.s, specific gravity was 1.0-1.1, and pH was 4.3-4.8. The average concentration of sucrose, fructose, and glucose was 1.10 g/L, 70 g/L 70 g/l, respectively for Pisang awak from lower altitude compared to 45-200 g/L 45-120 g/l and 45-120 g/L, respectively for Pisang awak from higher altitude. On the other hand, EAHB from North East Tanzania produced juice corresponding concentrations of 45 g/L, 56 g/L, and 55 g/L, respectively while another EAHB from North West of Tanzania had sucrose and fructose and glucose concentration of 155 g/L and 145 g/L. respectively. Dominant acids were malic and citric acids for pisang awak but succinic for EAHB. Dominant minerals in all cultivars were potassium 2.7-3.1 g/L followed by magnesium 0.6-2 g/L.

Keywords: banana juice, sugar content, acids, minerals, quality analysis

Procedia PDF Downloads 141
1445 World Agricultural Commodities Prices Dynamics and Volatilities Impacts on Commodities Importation and Food Security in West African Economic and Monetary Union Countries

Authors: Baoubadi Atozou, Koffi Akakpo

Abstract:

Since the decade 2000, the use of foodstuffs such as corn, wheat, and soybeans in biofuel production has been growing sharply in the United States, Canada, and Europe. Thus, prices for these agricultural products are rising in the world market. These cereals are the most important source of calorific energy for West African Economic and Monetary Union (WAEMU) countries members’ population. These countries are highly dependent on imports of most of these products. Thereby, rising prices can have an important impact on import levels and consequently on food security in these countries. This study aims to analyze the interrelationship between the prices of these commodities and their volatilities, and their effects on imports of these agricultural products by each WAEMU ’country member. The Autoregressive Distributed Lag (ARDL) model, the GARCH Multivariate model, and the Granger Causality Test are used in this investigation. The results show that import levels are highly and significantly sensitive to price changes as well as their volatility. In the short term as well as in the long term, there is a significant relationship between the prices of these products. There is a positive relationship in general between price volatility. And these volatilities have negative effects on the level of imports. The market characteristics affect food security in these countries, especially access to food for vulnerable and low-income populations. The policies makers must adopt viable strategies to increase agricultural production and limit their dependence on imports.

Keywords: price volatility, import of agricultural products, food safety, WAEMU

Procedia PDF Downloads 185
1444 Surface Roughness of AlSi/10%AlN Metal Matrix Composite Material Using the Taguchi Method

Authors: Nurul Na'imy Wan, Mohamad Sazali Said, Jaharah Ab. Ghani, Mohd Asri Selamat

Abstract:

This paper presents the surface roughness of the Aluminium silicon alloy (AlSi) matrix composite which has been reinforced with aluminium nitride (AlN), with three types of carbide inserts. Experiments were conducted at various cutting speeds, feed rates, and depths of cut, according to the Taguchi method, using a standard orthogonal array L27 (34). The signal-to-noise (S/N) ratio and analysis of variance are applied to study the characteristic performance of machining parameters in measuring the surface roughness during the milling operation. The analysis of results, using the Taguchi method concluded that a combination of low feed rate, medium depth of cut, low cutting speed, and insert TiB2 give a better value of surface roughness. From Taguchi method, it was found that cutting speed of 230m/min, feed rate of 0.4 mm/tooth, depth of cut of 0.5mm and type of insert of TiB2 were the optimal machining parameters that gave the optimal value of surface roughness.

Keywords: AlSi/AlN Metal Matrix Composite (MMC), surface roughness, Taguchi method

Procedia PDF Downloads 459
1443 Effect of Ginger Diets on in vitro Fermentation Characteristics, Enteric Methane Production and Performance of West African Dwarf Sheep

Authors: Dupe Olufunke Ogunbosoye, Thaofik Badmos Mustapha, Lanre Shaffihy Adeaga, R. O. Imam

Abstract:

Efforts have been made to reduce ruminants' methane emissions while improving animal productivity. Hence, an experiment was conducted to investigate the in vitro fermentation pattern, methane production, and performance of West African dwarf (WAD) rams-fed diets at graded levels of ginger. Sixteen (16) rams were randomly allocated into four dietary treatments with four animals per treatment in a completely randomized design for 84 days. Ginger powder was added at 0.00%, 0.25%, 0.50% and 0.75% as T1, T2, T3 and T4 respectively. The results indicated that at the 24-hour diet incubation, gas production, methane, metabolizable energy (ME), organic matter digestibility (OMD), and short-chain fatty acids (SCFA) concentrations decreased with the increasing level of ginger. Conversely, the sheep-fed T4 recorded the highest daily weight gain (47.61g/day), while the least daily weight gain (17.86g/day) was recorded in ram-fed T1. The daily weight gain of the rams fed T3 and T4 was similar but significantly different from the daily weight gain in T1 (17.86g/day) and T2 (29.76g/day). Daily feed intake was not significantly different across the treatments. T4 recorded the best response regarding feed conversion ratio (18.59) compared with other treatments. Based on the results obtained, rams fed T4 perform best in terms of growth and methane production. It is therefore concluded that the addition of ginger powder into the diet of sheep up to 0.75% enhances the growth rate of WAD sheep and reduces enteric methane production to create a smart nutrition system in ruminant animal production.

Keywords: enteric methane, growth, in vitro, sheep, nutrition system

Procedia PDF Downloads 70
1442 Identification of the Most Effective Dosage of Clove Oil Solution as an Alternative for Synthetic Anaesthetics on Zebrafish (Danio rerio)

Authors: D. P. N. De Silva, N. P. P. Liyanage

Abstract:

Zebrafish (Danio rerio) in the family Cyprinidae, is a tropical freshwater fish widely used as a model organism in scientific research. Use of effective and economical anaesthetic is very important when handling fish. Clove oil (active ingredient: eugenol) was identified as a natural product which is safer and economical compared to synthetic chemicals like methanesulfonate (MS-222). Therefore, the aim of this study was to identify the most effective dosage of clove oil solution as an anaesthetic on mature Zebrafish. Clove oil solution was prepared by mixing pure clove oil with 94% ethanol at a ratio of 1:9 respectively. From that solution, different volumes were selected as (0.4 ml, 0.6 ml and 0.8 ml) and dissolved in one liter of conditioned water (dosages : 0.4 ml/L, 0.6 ml/L and 0.8 ml/L). Water quality parameters (pH, temperature and conductivity) were measured before and after adding clove oil solution. Mature Zebrafish with similar standard length (2.76 ± 0.1 cm) and weight (0.524 ± 0.1 g) were selected for this experiment. Time taken for loss of equilibrium (initiation phase) and complete loss of movements including opercular movement (anaesthetic phase) were measured. To detect the efficacy on anaesthetic recovery, time taken to begin opercular movements (initiation of recovery phase) until swimming (post anaesthetic phase) were observed. The results obtained were analyzed according to the analysis of variance (ANOVA) and Tukeys’ method using SPSS version 17.0 at 95% confidence interval (p<0.5). According to the results, there was no significant difference at the initiation phase of anaesthesia in all three doses though the time taken was varied from 0.14 to 0.41 minutes. Mean value of the time taken to complete the anaesthetic phase at 0.4 ml/L dosage was significantly different with 0.6 ml/L and 0.8 ml/L dosages independently (p=0.01). There was no significant difference among recovery times at all dosages but 0.8 ml/L dosage took longer time compared to 0.6 ml/L dosage. The water quality parameters (pH and temperature) were stable throughout the experiment except conductivity, which increased with the higher dosage. In conclusion, the best dosage need to anaesthetize Zebrafish using clove oil solution was 0.6 ml/L due to its fast initiation of anaesthesia and quick recovery compared to the other two dosages. Therefore clove oil can be used as a good substitute for synthetic anaesthetics because of its efficacy at a lower dosage with higher safety at a low cost.

Keywords: anaesthetics, clove oil, zebrafish, Cyprinidae

Procedia PDF Downloads 711
1441 Socio-Economic Child’S Wellbeing Impasse in South Africa: Towards a Theory-Based Solution Model

Authors: Paulin Mbecke

Abstract:

Research Issue: Under economic constraints, socio-economic conditions of households worsen discounting child’s wellbeing to the bottom of many governments and households’ priority lists. In such situation, many governments fail to rebalance priorities in providing services such as education, housing and social security which are the prerequisites for the wellbeing of children. Consequently, many households struggle to respond to basic needs especially those of children. Although economic conditions play a crucial role in creating prosperity or poverty in households and therefore the wellbeing or misery for children; they are not the sole cause. Research Insights: The review of the South African Index of Multiple Deprivation and the South African Child Gauge establish the extent to which economic conditions impact on the wellbeing or misery of children. The analysis of social, cultural, environmental and structural theories demonstrates that non-economic factors contribute equally to the wellbeing or misery of children, yet, they are disregarded. In addition, the assessment of a child abuse database proves a weak correlation between economic factors (prosperity or poverty) and child’s wellbeing or misery. Theoretical Implications: Through critical social research theory and modelling, the paper proposes a Theory-Based Model that combines different factors to facilitate the understanding of child’s wellbeing or misery. Policy Implications: The proposed model assists in broad policy and decision making and reviews processes in promoting child’s wellbeing and in preventing, intervening and managing child’s misery with regard to education, housing, and social security.

Keywords: children, child’s misery, child’s wellbeing, household’s despair, household’s prosperity

Procedia PDF Downloads 276
1440 Appropriation of Cryptocurrencies as a Payment Method by South African Retailers

Authors: Neliswa Dyosi

Abstract:

Purpose - Using an integrated Technology-Organization-Environment (TOE) framework and the model of technology appropriation (MTA) as a theoretical lens, this interpretive qualitative study seeks to understand and explain the factors that influence the appropriation, non-appropriation, and disappropriation of bitcoin as a payment method by South African retailers. Design/methodology/approach –The study adopts the interpretivist philosophical paradigm. Multiple case studies will be adopted as a research strategy. For data collection, the study follows a qualitative approach. Qualitative data will be collected from the six retailers in various industries. Semi-structured interviews and documents will be used as the data collection techniques. Purposive and snowballing sampling techniques will be used to identify participants within the organizations. Data will be analyzed using thematic analysis. Originality/value - Using the deduction approach, the study seeks to provide a descriptive and explanatory contribution to theory. The study contributes to theory development by integrating the MTA and TOE frameworks as a means to understand technology adoption behaviors of organizations, in this case, retailers. This is also the first study that looks at an integrated approach of the Technology-Organization-Environment (TOE) framework and the MTA framework to understand the adoption and use of a payment method. South Africa is ranked amongst the top ten countries in the world on cryptocurrency adoption. There is, however, still a dearth of literature on the current state of adoption and usage of bitcoin as a payment method in South Africa. The study will contribute to the existing literature as bitcoin cryptocurrency is gaining popularity as an alternative payment method across the globe.

Keywords: cryptocurrency, bitcoin, payment methods, blockchain, appropriation, online retailers, TOE framework, disappropriation, non-appropriation

Procedia PDF Downloads 126
1439 Hypervirulent Klebsiella Pneumoniae in a South African Tertiary Hospital – Clinical Profile, Genetic Determinants and Virulence in Caenorhabditis Elegans

Authors: Dingiswayo Likhona, Arko-Cobbah Emmanuel, Carolina Pohl, Nthabiseng Z. Mokoena, Jolly Musoke

Abstract:

A distinct strain of Klebsiella pneumoniae (K. pneumoniae), referred to as hypervirulent (hvKp), is associated with invasive infections such as an invasive pyogenic liver abscess in young and healthy individuals. In South Africa, limited information is known about the prevalence and virulence of this hvKp strain. Thus, this study aimed to determine the prevalence of hvKp and virulence-associated factors in K. pneumoniae isolates from one of the largest Tertiary hospitals in a South African province. A total of 74 K. pneumoniae isolates were received from Pelonomi National Health Laboratory Services (NHLS), Bloemfontein. Virulence-associated genes (rmpA, capsule serotype K1/K2, iroB, and irp2) were screened, and the virulence of hvKp vs. classical Klebsiella pneumoniae (cKp) was investigated using Caenorhabditis elegans nematode model. The iutA (aerobactin transporter) gene was used as a primary biomarker of hvKp. An average of 12% (9/74) of cases were defined as hvKp. Moreover, hvKp was found to be significantly more virulent in vivo Caenorhabditis elegans relative to cKp. The virulence-associated genes (rmpA, iroB, hmv phenotype, and capsule K1/K2) were significantly (p< 0.05) associated with hvKp. Findings from this study confirm the presence of hvKp in one large Tertiary hospital in South Africa. However, the low prevalence and mild to moderate clinical presentation suggest a marginal threat to public health. Further studies in different settings are required to establish the true potential impact of hvKp in developing countries.

Keywords: hypervirulent klebsiella pneumoniae, virulence, caenorhabditis elegans, aerobactin (iutA)

Procedia PDF Downloads 76
1438 Effects of Alkalinity on the Treatment of Landfill Leachate through Algae Growth

Authors: Tahir Imran Qureshi

Abstract:

This study was aimed at finding out effects of potential influence of alkalinity on the treatment of landfill leachate through the growth of algae at varying dilution rates and toxicity potential. pH control proved to be an effective factor influencing on algal growth. With the use of algae Scenedesmus sp. for the treatment of leachate, a sharp increase in the growth of algae was recorded until pH 9. However, at pH 9.3 and 25 °C temperature, the growing trend of algae population showed a weakening tendency with the increase of total alkalinity in the leachate solution. Highest growth of algae was recorded in the leachate samples with alkalinity ranged at 1500-2500 mg CaCO3/L under neutral condition at pH 7 after 48 hours of cultivation time. Under the similar conditions, total nitrogen and total phosphorous in the leachate also reduced to 80% and 85%, respectively, however, no significant removal of COD was observed during the course of experiment.

Keywords: leachate treatment, microalgae, nutrient removal, ammonia toxicity

Procedia PDF Downloads 326
1437 Genetic Diversity of Wild Population of Heterobranchus Spp. Based on Mitochondria DNA Cytochrome C Oxidase Subunit I Gene Analysis

Authors: M. Y. Abubakar, Ipinjolu J. K., Yuzine B. Esa, Magawata I., Hassan W. A., Turaki A. A.

Abstract:

Catfish (Heterobranchus spp.) is a major freshwater fish that are widely distributed in Nigeria waters and are gaining rapid aquaculture expansion. However, indiscriminate artificial crossbreeding of the species with others poses a threat to their biodiversity. There is a paucity of information about the genetic variability, hence this insight on the genetic variability is badly needed, not only for the species conservation but for aquaculture expansion. In this study, we tested the level of Genetic diversity, population differentiation and phylogenetic relationship analysis on 35 individuals of two populations of Heterobranchus bidorsalis and 29 individuals of three populations of Heterobranchus longifilis using the mitochondrial cytochrome c oxidase subunit I (mtDNA COI) gene sequence. Nucleotide sequences of 650 bp fragment of the COI gene of the two species were compared. In the whole 4 and 5 haplotypes were distinguished in the populations of H. bidorsalis & H. longifilis with accession numbers (MG334168 - MG334171 & MG334172 to MG334176) respectively. Haplotypes diversity indices revealed a range of 0.59 ± 0.08 to 0.57 ± 0.09 in H. bidorsalis and 0.000 to 0.001051 ± 0.000945 in H. longifilis population, respectively. Analysis of molecular variance (AMOVA) revealed no significant variation among H. bidorsalis population of the Niger & Benue Rivers, detected significant genetic variation was between the Rivers of Niger, Kaduna and Benue population of H. longifilis. Two main clades were recovered, showing a clear separation between H. bidorsalis and H. longifilis in the phylogenetic tree. The mtDNA COI genes studied revealed high gene flow between populations with no distinct genetic differentiation between the populations as measured by the fixation index (FST) statistic. However, a proportion of population-specific haplotypes was observed in the two species studied, suggesting a substantial degree of genetic distinctiveness for each of the population investigated. These findings present the description of the species character and accessions of the fish’s genetic resources, through gene sequence submitted in Genetic database. The data will help to protect their valuable wild resource and contribute to their recovery and selective breeding in Nigeria.

Keywords: AMOVA, genetic diversity, Heterobranchus spp., mtDNA COI, phylogenetic tree

Procedia PDF Downloads 134
1436 Revisiting Dispute Resolution Mechanisms in the Southern African Development Community: A Proposal for Synchronization

Authors: Tapiwa Shumba, Nyaradzo D. T. Karubwa

Abstract:

Dispute resolution is the plinth of regional integration initiatives anchored on the rule of law and compliance with obligations. Without effective and reliable despite resolution mechanisms, it may be difficult to foster deeper integration. Within the Southern African Development Community (SADC) legal and institutional framework exists an apparent recognition that dispute resolution is an integral part of the regional integration. Almost all legal instruments of SADC include some provision for dispute resolution. Institutionally, the somewhat now defunct SADC Tribunal is meant to be the fulcrum for resolving disputes that arise under SADC instruments. However, after a closer analysis of the substance of these legal provisions and the attendant procedural mechanisms for addressing disputes, an argument can be made that dispute resolution in SADC is somewhat scant, fragmented and neglected. In most instruments, the common provision on dispute resolution appears to be a ‘mid-night clause’. In other instruments which have specialised provisions and procedures, questions of practicality and genius cannot be avoided. Worse still there now appears to be a lack of magnanimity between the substantive provisions in various instruments and the role of the transformed Tribunal. This scant, fragmented and neglected dispute resolution system may have an impact on the observance of the rule of law and compliance with obligations in the rules-based SADC system. This all, in turn, has an effect on the common agenda for deeper regional integration. This article seeks to expose this scant, fragmented and neglected SADC dispute resolution system and to propose a harmonised system that addresses these challenges. A ‘one stop shop’ system under a strengthened SADC tribunal is proposed as a responsive solution.

Keywords: regional integration, harmonisation, SADC tribunal, dispute resolution

Procedia PDF Downloads 183
1435 Surface Roughness Modeling in Dry Face Milling of Annealed and Hardened AISI 52100 Steel

Authors: Mohieddine Benghersallah, Mohamed Zakaria Zahaf, Ali Medjber, Idriss Tibakh

Abstract:

The objective of this study is to analyse the effects of cutting parameters on surface roughness in dry face milling using statistical techniques. We studied the effect of the microstructure of AISI 52100 steel on machinability before and after hardening. The machining tests were carried out on a high rigidity vertical milling machine with a 25 mm diameter face milling cutter equipped with micro-grain bicarbide inserts with PVD (Ti, AlN) coating in GC1030 grade. A Taguchi L9 experiment plan is adopted. Analysis of variance (ANOVA) was used to determine the effects of cutting parameters (Vc, fz, ap) on the roughness (Ra) of the machined surface. Regression analysis to assess the machinability of steel presented mathematical models of roughness and the combination of parameters to minimize it. The recorded results show that feed per tooth has the most significant effect on the surface condition for both steel treatment conditions. The best roughnesses were obtained for the hardened AISI 52100 steel.

Keywords: machinability, heat treatment, microstructure, surface roughness, Taguchi method

Procedia PDF Downloads 143
1434 Analysis of the Factors Affecting the Public Bicycle Projects in Chinese Cities

Authors: Xiujuan Wang, Weiguo Wang, Lei Yu, Xue Liu

Abstract:

There are many purported benefits of public bike systems, therefore, it has seen a sharp increase since 2008 in Hangzhou, China. However, there are few studies on the public bicycle system in Chinese cities. In order to make recommendations for the development of public bicycle systems, this paper analyzes the influencing factors by using the system dynamics method according to the main characteristics of Chinese cities. The main characteristics of Chinese cities lie in the city size and process of urbanization, traffic mode division, demographic characteristics, bicycle infrastructure and right of way, regime structure. Finally, under the context of Chinese bike sharing systems, these analyses results can help to design some feasible strategies for the planner to the development of the public bicycles.

Keywords: engineering of communication and transportation system, bicycle, public bike, characteristics of Chinese cities, system dynamics

Procedia PDF Downloads 229
1433 Mutation Profiling of Paediatric Solid Tumours in a Cohort of South African Patients

Authors: L. Lamola, E. Manolas, A. Krause

Abstract:

Background: The incidence of childhood cancer incidence is increasing gradually in low-middle income countries, such as South Africa. Globally, there is an extensive range of familial- and hereditary-cancer syndromes, where underlying germline variants increase the likelihood of developing cancer in childhood. Next-Generation Sequencing (NGS) technologies have been key in determining the occurrence and genetic contribution of germline variants to paediatric cancer development. We aimed to design and evaluate a candidate gene panel specific to inherited cancer-predisposing genes to provide a comprehensive insight into the contribution of germline variants to childhood cancer. Methods: 32 paediatric patients (aged 0-18 years) diagnosed with a malignant tumour were recruited, and biological samples were obtained. After quality control, DNA was sequenced using an ion Ampliseq 50 candidate gene panel design and Ion Torrent S5 technologies. Sequencing variants were called using Ion Torrent Suite software and were subsequently annotated using Ion Reporter and Ensembl's VEP. High priority variants were manually analysed using tools such as MutationTaster, SIFT-INDEL and VarSome. Putative identified candidates were validated via Sanger Sequencing. Results: The patients studied had a variety of cancers, the most common being nephroblastoma (13), followed by osteosarcoma (4) and astrocytoma (3). We identified 10 pathogenic / likely pathogenic variants in 10 patients, most of which were novel. Conclusions: According to the literature, we expected ~10% of our patient population to harbour pathogenic or likely pathogenic germline variants, however, we reported about 3 times (~30%) more than we expected. Majority of the identified variants are novel; this may be because this is the first study of its kind in an understudied South African population.

Keywords: Africa, genetics, germline-variants, paediatric-cancer

Procedia PDF Downloads 131
1432 Status of Physical, Chemical and Biological Attributes of Isheri, Ogun River, in Relation to the Surrounding Anthropogenic Activities of Kara Abattoir, South West Nigeria

Authors: N. B. Ikenweiwe, A. A. Alimi, N. A. Bamidele, A. O. Ewumi, J. Dairo, I. A. Akinnubi, S. O. Otubusin

Abstract:

A study on the physical, chemical and biological parameters of the lower course of Ogun River, Isheri-Olofin was carried out between January and December 2014 in order to determine the effects of the anthropogenic activities of the Kara abattoir and domestic waste depositions on the quality of the water. Water samples were taken twice each month at three selected stations A, B and C (based on characteristic features or activity levels) along the water course. Samples were analysed using standard methods for chemical and biological parameters the same day in the laboratory while physical parameters were determined in-situ with water parameters kit. Generally, results of Transparency, Dissolved Oxygen, Nitrates, TDS and Alkalinity fall below the permissible limits of WHO and FEPA standards for drinking and fish production. Results of phosphates, lead and cadmium were also low but still within the permissible limit. Only Temperature and pH were within limit. Low plankton community, (phytoplankton, zooplankton), which ranges from 3, 5 to 40, 23 were as a result of low levels of DO, transparency and phosphate. The presence of coliform bacteria of public health importance like Escherichia coli, Proteus vulgaris, Aeromonas sp., Shigella sp, Enterobacter aerogenes as well as gram negative bacteria Proteus morganii are mainly indicators of faecal pollution. Fish and other resources obtained from this water stand the risk of being contaminated with these organisms and man is at the receiving end. The results of the physical, chemical and some biological parameters of Isheri, Ogun River, according to this study showed that the live forms of aquatic and fisheries resources there are dwelling under stress as a result of deposition of bones, horns, faecal components, slurry of suspended solids, fat and blood into the water. Government should therefore establish good monitoring system against illegal waste depositions and create education programmes that will enlighten the community on the social, ecological and economic values of the river.

Keywords: water parameters, Isheri Ogun river, anthropogenic activities, Kara abattoir

Procedia PDF Downloads 529
1431 Ecological and Health Risk Assessment of the Heavy Metal Contaminant in Surface Soils around Effurun Market

Authors: A. O. Ogunkeyede, D. Amuchi, A. A. Adebayo

Abstract:

Heavy metal contaminations in soil have received great attention. Anthropogenic activities such as vehicular emission, industrial activities and constructions have resulted in elevated concentration of heavy metals in the surface soils. The metal particles can be free from the surface soil when they are disturbed and re-entrained in air, which necessitated the need to investigate surface soil at market environment where adults and children are present on daily basis. This study assesses concentration of heavy metal pollution, ecological and health risk factors in surface soil at Effurun market. 8 samples were collected at household material (EMH), fish (EMFs), fish and commodities (EMF-C), Abattoir (EMA 1 & 2), fruit sections (EMF 1 & 2) and lastly main road (EMMR). The samples were digested and analyzed in triplicate for contents of Lead (Pb), Nickel (Ni), Cadmium (Cd) and Copper (Cu). The mean concentration of the Pb mg/kg (112.27 ± 1.12) and Cu mg/kg (156.14 ± 1.10) were highest in the abattoir section (EMA 1). The mean concentrations of the heavy metal were then used to calculate the ecological and health risk for people within the market. Pb contamination at EMMR, EMF 2, EMFs were moderately while Pb shows considerable contamination at EMH, EMA 1, EMA 2 and EMF-C sections of the Effurun market. The ecological risk factor varies between low to moderate pollution for Pb and EMA 1 has the highest potential ecological risk that falls within moderate pollution. The hazard quotient results show that dermal exposure pathway is the possible means of heavy metal exposure to the traders while ingestion is the least sources of exposure to adult. The ingestion suggested that children around the EMA 1 have the highest possible exposure to children due to hand-to-mouth and object-to-mouth behaviour. The results further show that adults at the EMA1 will have the highest exposure to Pb due to inhalation during burning of cow with tyre that contained Pb and Cu. The carcinogenic risk values of most sections were higher than acceptable values, while Ni at EMMR, EMF 1 & 2, EMFs and EMF-C sections that were below the acceptable values. The cancer risk for inhalation exposure pathway for Pb (1.01E+17) shows a significant level of contamination than all the other sections of the market. It suggested that the people working at the Abattoir were very prone to cancer risk.

Keywords: carcinogenic, ecological, heavy metal, risk

Procedia PDF Downloads 137
1430 The Effect of Gender Role Socialization on Marketing of Gendered Products: The Case of Cultural Ghana

Authors: Priscilla Adoley Moffat

Abstract:

One common element of African cultures is gender role socialization. This is a significant component of African cultures because gender roles are considered in these cultures, to define males and females and distinguish males from females. Various studies have established the impact of gender role socialization on individuals, on activities of individuals, including business activities, and on society, in general. This study further examined the effect of gender role socialization on the marketing of gendered products. The study sought to establish whether gender role socialization affects marketing, particularly word-of-mouth marketing, of gender-specific products. For a comprehensive examination of the influence of gender role socialization on word-of-mouth marketing of gendered products, 2150 respondents (1075 males and 1075 females), comprising 550 students of Marketing from various Ghanaian universities/colleges and 1600 other individuals (100 from each of the 16 regions of Ghana, representing the various cultures) were randomly sampled and interviewed. The study found that females are more willing to market male products than males when tasked to market female products. Also, females are more efficient in marketing male products than males in marketing female products. Again, most female audiences feel uncomfortable or embarrassed and are less receptive when approached by a male marketer of female products. Then, the study found that the fear of stigmatization is a major influencer of males’ negative attitude towards marketing of female products and that female marketers of male products, however, suffer less or no stigma. Aside from its addition to the literature on the impact of gender role socialization on marketing and, for that matter, the influence of socialization on marketing, the findings of the study are useful to multinational companies, which become better informed in their strategy when assigning marketing roles, especially in Africa.

Keywords: gender, socialization, marketing, gendered, role, Ghana

Procedia PDF Downloads 58
1429 Surface Roughness Effects in Pure Sliding EHL Line Contacts with Carreau-Type Shear-Thinning Lubricants

Authors: Punit Kumar, Niraj Kumar

Abstract:

The influence of transverse surface roughness on EHL characteristics has been investigated numerically using an extensive set of full EHL line contact simulations for shear-thinning lubricants under pure sliding condition. The shear-thinning behavior of lubricant is modeled using Carreau viscosity equation along with Doolittle-Tait equation for lubricant compressibility. The surface roughness is assumed to be sinusoidal and it is present on the stationary surface. It is found that surface roughness causes sharp pressure peaks along with reduction in central and minimum film thickness. With increasing amplitude of surface roughness, the minimum film thickness decreases much more rapidly as compared to the central film thickness.

Keywords: EHL, Carreau, shear-thinning, surface roughness, amplitude, wavelength

Procedia PDF Downloads 724
1428 Effect of Copper Ions Doped-Hydroxyapatite 3D Fiber Scaffold

Authors: Adil Elrayah, Jie Weng, Esra Suliman

Abstract:

The mineral in human bone is not pure stoichiometric calcium phosphate (Ca/P) as it is partially substituted by in organic elements. In this study, the copper ions (Cu2+) substituted hydroxyapatite (CuHA) powder has been synthesized by the co-precipitation method. The CuHA powder has been used to fabricate CuHA fiber scaffolds by sol-gel process and the following sinter process. The resulted CuHA fibers have slightly different microstructure (i.e. porosity) compared to HA fiber scaffold, which is denser. The mechanical properties test was used to evaluate CuHA, and the results showed decreases in both compression strength and hardness tests. Moreover, the in vitro used endothelial cells to evaluate the angiogenesis of CuHA. The result illustrated that the viability of endothelial cell on CuHA fiber scaffold surfaces tends to antigenic behavior. The results obtained with CuHA scaffold give this material benefit in biological applications such as antimicrobial, antitumor, antigens, compacts, filling cavities of the tooth and for the deposition of metal implants anti-tumor, anti-cancer, bone filler, and scaffold.

Keywords: fiber scaffold, copper ions, hydroxyapatite, in vitro, mechanical property

Procedia PDF Downloads 148
1427 Physicochemical Properties and Thermal Inactivation of Polyphenol Oxidase of African Bush Mango (Irvingia Gabonensis) Fruit

Authors: Catherine Joke Adeseko

Abstract:

Enzymatic browning is an economically important disorder that degrades organoleptic properties and prevent the consumer from purchasing fresh fruit and vegetables. Prevention and control of enzymatic browning in fruit and its product is imperative. Therefore, this study sought to investigate the catalytic effect of polyphenol oxidase (PPO) in the adverse browning of African bush mango (Irvingia gabonensis) fruit peel and pulp. PPO was isolated and purified, and its physicochemical properties, such as the effect of pH with SDS, temperature, and thermodynamic studies, which invariably led to thermal inactivation of purified PPO at 80 °C, were evaluated. The pH and temperature optima of PPO were found at 7.0 and 50, respectively. There was a gradual increase in the activity of PPO as the pH increases. However, the enzyme exhibited a higher activity at neutral pH 7.0, while enzymatic inhibition was observed at acidic region, pH 2.0. The presence of SDS at pH 5.0 downward was found to inhibit the activity of PPO from the peel and pulp of I. gabonensis. The average value of enthalpy (ΔH), entropy (ΔS), and Gibbs free energy (ΔG) obtained at 20 min of incubation and temperature 30 – 80 °C were respectively 39.93 kJ.mol-1, 431.57 J.mol-1 .K-1 and -107.99 kJ.mol-1 for peel PPO, and 37.92 kJ.mol-1, -442.51J.mol-1.K-1, and -107.22 kJ.mol-1 for pulp PPO. Thermal inactivation of PPO from I. gabonensis exhibited a reduction in catalytic activity as the temperature and duration of heat inactivation increases using catechol, reflected by an increment in k value. The half-life of PPO (t1/2) decreases as the incubation temperature increases due to the instability of the enzyme at high temperatures and was higher in pulp than peel. Both D and Z values decrease with increase in temperature. The information from this study suggests processing parameters for controlling PPO in the potential industrial application of I. gabonensis fruit in order to prolong the shelf-life of this fruit for maximum utilization.

Keywords: enzymatic, browning, characterization, activity

Procedia PDF Downloads 79
1426 Mixing Enhancement with 3D Acoustic Streaming Flow Patterns Induced by Trapezoidal Triangular Structure Micromixer Using Different Mixing Fluids

Authors: Ayalew Yimam Ali

Abstract:

The T-shaped microchannel is used to mix both miscible or immiscible fluids with different viscosities. However, mixing at the entrance of the T-junction microchannel can be difficult mixing phenomena due to micro-scale laminar flow aspects with the two miscible high-viscosity water-glycerol fluids. One of the most promising methods to improve mixing performance and diffusion mass transfer in laminar flow phenomena is acoustic streaming (AS), which is a time-averaged, second-order steady streaming that can produce rolling motion in the microchannel by oscillating a low-frequency range acoustic transducer and inducing an acoustic wave in the flow field. The newly developed 3D trapezoidal, triangular structure spine used in this study was created using sophisticated CNC machine cutting tools used to create microchannel mold with a 3D trapezoidal triangular structure spine alone the T-junction longitudinal mixing region. In order to create the molds for the 3D trapezoidal structure with the 3D sharp edge tip angles of 30° and 0.3mm trapezoidal, triangular sharp edge tip depth from PMMA glass (Polymethylmethacrylate) with advanced CNC machine and the channel manufactured using PDMS (Polydimethylsiloxane) which is grown up longitudinally on the top surface of the Y-junction microchannel using soft lithography nanofabrication strategies. Flow visualization of 3D rolling steady acoustic streaming and mixing enhancement with high-viscosity miscible fluids with different trapezoidal, triangular structure longitudinal length, channel width, high volume flow rate, oscillation frequency, and amplitude using micro-particle image velocimetry (μPIV) techniques were used to study the 3D acoustic streaming flow patterns and mixing enhancement. The streaming velocity fields and vorticity flow fields show 16 times more high vorticity maps than in the absence of acoustic streaming, and mixing performance has been evaluated at various amplitudes, flow rates, and frequencies using the grayscale value of pixel intensity with MATLAB software. Mixing experiments were performed using fluorescent green dye solution with de-ionized water in one inlet side of the channel, and the de-ionized water-glycerol mixture on the other inlet side of the T-channel and degree of mixing was found to have greatly improved from 67.42% without acoustic streaming to 0.96.83% with acoustic streaming. The results show that the creation of a new 3D steady streaming rolling motion with a high volume flowrate around the entrance was enhanced by the formation of a new, three-dimensional, intense streaming rolling motion with a high-volume flowrate around the entrance junction mixing zone with the two miscible high-viscous fluids which are influenced by laminar flow fluid transport phenomena.

Keywords: micro fabrication, 3d acoustic streaming flow visualization, micro-particle image velocimetry, mixing enhancement.

Procedia PDF Downloads 8
1425 An Analysis of the Strategic Pathway to Building a Successful Mobile Advertising Business in Nigeria: From Strategic Intent to Competitive Advantage

Authors: Pius A. Onobhayedo, Eugene A. Ohu

Abstract:

Nigeria has one of the fastest growing mobile telecommunications industry in the world. In the absence of fixed connection access to the Internet, access to the Internet is primarily via mobile devices. It, therefore, provides a test case for how to penetrate the mobile market in an emerging economy. We also hope to contribute to a sparse literature on strategies employed in building successful data-driven mobile businesses in emerging economies. We, therefore, sought to identify and analyse the strategic approach taken in a successful locally born mobile data-driven business in Nigeria. The analysis was carried out through the framework of strategic intent and competitive advantages developed from the conception of the company to date. This study is based on an exploratory investigation of an innovative digital company based in Nigeria specializing in the mobile advertising business. The projected growth and high adoption of mobile in this African country, coinciding with the smartphone revolution triggered by the launch of iPhone in 2007 opened a new entrepreneurial horizon for the founder of the company, who reached the conclusion that ‘the future is mobile’. This dream led to the establishment of three digital businesses, designed for convergence and complementarity of medium and content. The mobile Ad subsidiary soon grew to become a truly African network with operations and campaigns across West, East and South Africa, successfully delivering campaigns in several African countries including Nigeria, Kenya, South Africa, Ghana, Uganda, Zimbabwe, and Zambia amongst others. The company recently declared a 40% year-end profit which was nine times that of the previous financial year. This study drew from an in-depth interview with the company’s founder, analysis of primary and secondary data from and about the business, as well as case studies of digital marketing campaigns. We hinge our analysis on the strategic intent concept which has been proposed to be an engine that drives the quest for sustainable strategic advantage in the global marketplace. Our goal was specifically to identify the strategic intents of the founder and how these were transformed creatively into processes that may have led to some distinct competitive advantages. Along with the strategic intents, we sought to identify the respective absorptive capacities that constituted favourable antecedents to the creation of such competitive advantages. Our recommendations and findings will be pivotal information for anybody wishing to invest in the world’s fastest technology business space - Africa.

Keywords: Africa, competitive advantage, competitive strategy, digital, mobile business, marketing, strategic intent

Procedia PDF Downloads 432
1424 The Research of Weights Identify of Harbin Ecological Security Evaluation Index Based on AHP

Authors: Rong Guo, Mengshi Huang, Yujing Bai

Abstract:

With the rapid development of urbanization, the urban population increases and urban sprawl appeared. And these issues led to a sharp deterioration of the ecological environment. So, the urban ecological security evaluation was imminent. The weights identify of index was a key step of the research of ecological security evaluation. The AHP was widely used in the extensive research of weights identify of ecological security index. The characteristics of authority and quantitative can fully reflect the views of relevant experts. On the basis of building the ecological security evaluation index of Harbin, the paper combed and used the basic principle of the AHP, and calculated the weights of Harbin ecological security evaluation index through the process of the expert opinions “summary-feedback-summary”. And lay a foundation of future study of Harbin ecological security index, and guide the quantitative evaluation of Harbin ecological security.

Keywords: AHP, ecological security, evaluation Index, weights identify, harbin

Procedia PDF Downloads 486
1423 Variations and Anomalies of the Posterior Cerebral Artery in a South African Population

Authors: Karen Cilliers, Benedict J. Page

Abstract:

Limited research focuses on the anatomy of the posterior cerebral artery (PCA) and its cortical branches, even though there can be variation in the presence, size, and origin. The PCA branching pattern has not been adequately reported, and the true division point remains unclear. Anomalies of the PCA have been described in the previous literature; however, few examples have been reported. Furthermore, possible differences between right and left, sex, population and age groups may exist. Therefore, the aim of this study was to report on these aspects from a South African population. One hundred and twenty-six hemispheres were obtained consisting of 86 males and 38 females, between the ages of 22 and 84 (average 45 years of age). This comprised of three population groups, namely coloured (n=74), black (n=38), white (n=10) and two unknown cases. The PCA was injected with an isotonic saline and a colored silicone. The external diameter was measured with a digital micrometer, and length was measured with a string and a ruler. Presence and origins of the cortical branches were similar to the literature; however, duplications, triplications, and unusual origins were observed. The diameter and lengths indicated significant differences between the right and left sides, sex, population and age groups. Branching patterns were identified and compared to the prevalence from previous studies. Two fenestrations were observed in the P2A segment. The presence, size, origin, branching pattern and anomalies of the PCA were investigated in this study. The diameter and length can be significantly different, especially between the right and left-hand side. Changes in the diameter and length can be indicative of certain neuropathological conditions and can play a role in aneurysms formation. Adequate knowledge of the normal and abnormal PCA anatomy is crucial for surgery in the vicinity of the PCA. Therefore, future studies should focus on these aspects.

Keywords: branching, cortical branches, fenestration, posterior cerebral artery

Procedia PDF Downloads 218
1422 Winning the Future of Education in Africa through Project Base Learning: How the Implementation of PBL Pedagogy Can Transform Africa’s Educational System from Theory Base to Practical Base in School Curriculum

Authors: Bismark Agbemble

Abstract:

This paper talks about how project-based learning (PBL) is being infused or implemented in the educational sphere of Africa. The paper navigates through the liminal aspects of PBL as a pedagogical approach to bridge the divide between theoretical knowledge and its application within school curriculums. Given that contextualized learning can be embodied, the abstract vehemently discusses that PBL creates an opportunity for students to work on projects that are of academic relevance in their local settings. It presents PBL’s growth of critical thinking, problem-solving, cooperation, and communications, which is vital in getting young citizens to prepare for the 21st-century revolution. In addition, the abstract stresses the possibility that PBL could become a stimulus to creativity and innovation wherein learning becomes motivated from within by intrinsic motivations. The paper advocates for a holistic approach that is based on teacher’s professional development with the provision of adequate infrastructural facilities and resource allocation, thus ensuring the success and sustainability of PBLs in African education systems. In the end, the paper positions this as a transformative educational methodology that has great potential in helping to shape an African generation that is prepared for a great future.

Keywords: student centered pedagogy, constructivist learning theory, self-directed learning, active exploration, real world challenges, STEM, 21st century skills, curriculum design, classroom management, project base learning curriculum, global intelligence, social and communication skills, transferable skills, critical thinking, investigatable learning, life skills

Procedia PDF Downloads 49
1421 Interculturalizing Ethiopian Universities: Between Initiation and Institutionalization

Authors: Desta Kebede Ayana, Lies Sercu, Demelash Mengistu

Abstract:

The study is set in Ethiopia, a sub-Saharan multilingual, multiethnic African country, which has seen a significant increase in the number of universities in recent years. The aim of this growth is to provide access to education for all cultural and linguistic groups across the country. However, there are challenges in promoting intercultural competence among students in this diverse context. The aim of the study is to investigate the interculturalization of Ethiopian Higher Education Institutions as perceived by university lecturers and administrators. In particular, the study aims to determine the level of support for this educational innovation and gather suggestions for its implementation and institutionalization. The researchers employed semi-structured interviews with administrators and lecturers from two large Ethiopian universities to gather data. Thematic analysis was utilized for coding and analyzing the interview data, with the assistance of the NVIVO software. The findings obtained from the grounded analysis of the interview data reveal that while there are opportunities for interculturalization in the curriculum and campus life, support for educational innovation remains low. Administrators and lecturers also emphasize the government's responsibility to prioritize interculturalization over other educational innovation goals. The study contributes to the existing literature by examining an under-researched population in an under-researched context. Additionally, the study explores whether Western perspectives of intercultural competence align with the African context, adding to the theoretical understanding of intercultural education. The data for this study was collected through semi-structured interviews conducted with administrators and lecturers from two large Ethiopian universities. The interviews allowed for an in-depth exploration of the participants' views on interculturalization in higher education. Thematic analysis was applied to the interview data, allowing for the identification and organization of recurring themes and patterns. The analysis was conducted using the NVIVO software, which aided in coding and analyzing the data. The study addresses the extent to which administrators and lecturers support the interculturalization of Ethiopian Higher Education Institutions. It also explores their suggestions for implementing and institutionalizing intercultural education, as well as their perspectives on the current level of institutionalization. The study highlights the challenges in interculturalizing Ethiopian universities and emphasizes the need for greater support and prioritization of intercultural education. It also underscores the importance of considering the African context when conceptualizing intercultural competence. This research contributes to the understanding of intercultural education in diverse contexts and provides valuable insights for policymakers and educational institutions aiming to promote intercultural competence in higher education settings.

Keywords: administrators, educational change, Ethiopia, intercultural competence, lecturers

Procedia PDF Downloads 88
1420 Honey: A Remedy Rediscovered in the Treatment of Oral Diseases

Authors: Muhammad Mansoor Majeed, Imtiaz Ahmed

Abstract:

For centuries, honey has been used for the management and cure of different diseases for the treatment of wound, ulcers, burns, cough, and sore throat, etc. It has also been proved to decrease inflammation, edema, and exudates in different body tissues. This study is performed to find out the effectiveness of honey in the treatment and prevention of gingivitis, gingival bleeding, and accumulation of plaque. Randomized control trial was performed on two subject groups. Honey provided to one subject group to apply on their gums and tooth and then gargle with water and drink. Frequency of the procedure is thrice a day for a month. Another group was given a placebo. Before and after, readings were taken according to Loe and Silness Plaque and Gingival Index. Initially, the mean plaque index, Gingival index and the percentage of sites which were bleeding in the honey group was 0.910, 0.800 and 58.71% respectively which has reduced to 0.313, 0.296 and 27.6% in 30 ± 3 days whereas the control group did not show signs of improvement. Visible changed has observed in the honey group from 0.910 to 0.313 in mean plaque index, 0.800 to 0.296 in Gingival Index, and the percentage of bleeding sited decreased from 58.71% to 27.6%. No significant changes observed in another group. We can conclude that honey reduces the formation/accumulation of plaque and decreases gingival bleeding as well as it has therapeutic effects.

Keywords: honey, gingivitis, Pakistan, bleeding gums

Procedia PDF Downloads 125
1419 Cognitive Linguistic Features Underlying Spelling Development in a Second Language: A Case Study of L2 Spellers in South Africa

Authors: A. Van Staden, A. Tolmie, E. Vorster

Abstract:

Research confirms the multifaceted nature of spelling development and underscores the importance of both cognitive and linguistic skills that affect sound spelling development such as working and long-term memory, phonological and orthographic awareness, mental orthographic images, semantic knowledge and morphological awareness. This has clear implications for many South African English second language spellers (L2) who attempt to become proficient spellers. Since English has an opaque orthography, with irregular spelling patterns and insufficient sound/grapheme correspondences, L2 spellers can neither rely, nor draw on the phonological awareness skills of their first language (for example Sesotho and many other African languages), to assist them to spell the majority of English words. Epistemologically, this research is informed by social constructivism. In addition the researchers also hypothesized that the principles of the Overlapping Waves Theory was an appropriate lens through which to investigate whether L2 spellers could significantly improve their spelling skills via the implementation of an alternative route to spelling development, namely the orthographic route, and more specifically via the application of visual imagery. Post-test results confirmed the results of previous research that argues for the interactive nature of different cognitive and linguistic systems such as working memory and its subsystems and long-term memory, as learners were systematically guided to store visual orthographic images of words in their long-term lexicons. Moreover, the results have shown that L2 spellers in the experimental group (n = 9) significantly outperformed L2 spellers (n = 9) in the control group whose intervention involved phonological awareness (and coding) including the teaching of spelling rules. Consequently, L2 learners in the experimental group significantly improved in all the post-test measures included in this investigation, namely the four sub-tests of short-term memory; as well as two spelling measures (i.e. diagnostic and standardized measures). Against this background, the findings of this study look promising and have shown that, within a social-constructivist learning environment, learners can be systematically guided to apply higher-order thinking processes such as visual imagery to successfully store and retrieve mental images of spelling words from their output lexicons. Moreover, results from the present study could play an important role in directing research into this under-researched aspect of L2 literacy development within the South African education context.

Keywords: English second language spellers, phonological and orthographic coding, social constructivism, visual imagery as spelling strategy

Procedia PDF Downloads 349
1418 Flow Visualization and Mixing Enhancement in Y-Junction Microchannel with 3D Acoustic Streaming Flow Patterns Induced by Trapezoidal Triangular Structure using High-Viscous Liquids

Authors: Ayalew Yimam Ali

Abstract:

The Y-shaped microchannel is used to mix both miscible or immiscible fluids with different viscosities. However, mixing at the entrance of the Y-junction microchannel can be a difficult mixing phenomena due to micro-scale laminar flow aspects with the two miscible high-viscosity water-glycerol fluids. One of the most promising methods to improve mixing performance and diffusion mass transfer in laminar flow phenomena is acoustic streaming (AS), which is a time-averaged, second-order steady streaming that can produce rolling motion in the microchannel by oscillating a low-frequency range acoustic transducer and inducing an acoustic wave in the flow field. The developed 3D trapezoidal, triangular structure spine used in this study was created using sophisticated CNC machine cutting tools used to create microchannel mold with a 3D trapezoidal triangular structure spine alone the Y-junction longitudinal mixing region. In order to create the molds for the 3D trapezoidal structure with the 3D sharp edge tip angles of 30° and 0.3mm trapezoidal triangular sharp edge tip depth from PMMA glass (Polymethylmethacrylate) with advanced CNC machine and the channel manufactured using PDMS (Polydimethylsiloxane) which is grown up longitudinally on top surface of the Y-junction microchannel using soft lithography nanofabrication strategies. Flow visualization of 3D rolling steady acoustic streaming and mixing enhancement with high-viscosity miscible fluids with different trapezoidal, triangular structure longitudinal length, channel width, high volume flow rate, oscillation frequency, and amplitude using micro-particle image velocimetry (μPIV) techniques were used to study the 3D acoustic streaming flow patterns and mixing enhancement. The streaming velocity fields and vorticity flow fields show 16 times more high vorticity maps than in the absence of acoustic streaming, and mixing performance has been evaluated at various amplitudes, flow rates, and frequencies using the grayscale value of pixel intensity with MATLAB software. Mixing experiments were performed using fluorescent green dye solution with de-ionized water in one inlet side of the channel, and the de-ionized water-glycerol mixture on the other inlet side of the Y-channel and degree of mixing was found to have greatly improved from 67.42% without acoustic streaming to 0.96.83% with acoustic streaming. The results show that the creation of a new 3D steady streaming rolling motion with a high volume flowrate around the entrance was enhanced by the formation of a new, three-dimensional, intense streaming rolling motion with a high-volume flowrate around the entrance junction mixing zone with the two miscible high-viscous fluids which are influenced by laminar flow fluid transport phenomena.

Keywords: micro fabrication, 3d acoustic streaming flow visualization, micro-particle image velocimetry, mixing enhancement

Procedia PDF Downloads 9