Search results for: small and medium enterprises (SMEs)
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 7430

Search results for: small and medium enterprises (SMEs)

5210 Formation Mechanism of Macroporous Cu/CuSe and Its Application as Electrocatalyst for Methanol Oxidation Reaction

Authors: Nabi Ullah

Abstract:

The single-step solvothermal method is used to prepare Cu/CuSe as an electrocatalyst for methanol electro-oxidation reaction (MOR). 1,3-butane-diol is selected as a reaction medium, whose viscosity and complex formation with Cu(II) ions dictate the catalyst morphology. The catalyst has a macroporous structure, which is composed of nanoballs with a high purity, crystallinity, and uniform morphology. The electrocatalyst is excellent for MOR, as it delivers a current density of 37.28 mA/mg at a potential of 0.6 V (vs Ag/AgCl) in the electrolyte of 1 M KOH and 0.75 M methanol at a 50 mV/s scan rate under conditions of cyclic voltammetry. The catalyst also shows good stability for 3600 s with negligible charge transfer resistance and a high electrochemical active surface area (ECSA) value of 0.100 mF/cm².

Keywords: MOR, copper selenide, electocatalyst, energy application

Procedia PDF Downloads 47
5209 The Effect of Adhesion on the Frictional Hysteresis Loops at a Rough Interface

Authors: M. Bazrafshan, M. B. de Rooij, D. J. Schipper

Abstract:

Frictional hysteresis is the phenomenon in which mechanical contacts are subject to small (compared to contact area) oscillating tangential displacements. In the presence of adhesion at the interface, the contact repulsive force increases leading to a higher static friction force and pre-sliding displacement. This paper proposes a boundary element model (BEM) for the adhesive frictional hysteresis contact at the interface of two contacting bodies of arbitrary geometries. In this model, adhesion is represented by means of a Dugdale approximation of the total work of adhesion at local areas with a very small gap between the two bodies. The frictional contact is divided into sticking and slipping regions in order to take into account the transition from stick to slip (pre-sliding regime). In the pre-sliding regime, the stick and slip regions are defined based on the local values of shear stress and normal pressure. In the studied cases, a fixed normal force is applied to the interface and the friction force varies in such a way to start gross sliding in one direction reciprocally. For the first case, the problem is solved at the smooth interface between a ball and a flat for different values of work of adhesion. It is shown that as the work of adhesion increases, both static friction and pre-sliding distance increase due to the increase in the contact repulsive force. For the second case, the rough interface between a glass ball against a silicon wafer and a DLC (Diamond-Like Carbon) coating is considered. The work of adhesion is assumed to be identical for both interfaces. As adhesion depends on the interface roughness, the corresponding contact repulsive force is different for these interfaces. For the smoother interface, a larger contact repulsive force and consequently, a larger static friction force and pre-sliding distance are observed.

Keywords: boundary element model, frictional hysteresis, adhesion, roughness, pre-sliding

Procedia PDF Downloads 158
5208 Poly(ε-Caprolactone)-Based Bilayered Scaffolds Prepared by Electrospinning for Tissue Engineering of Small-Diameter Vascular Grafts

Authors: Mohammed Fayez Al Rez

Abstract:

Nowadays, there is an unmet clinical need for new small-diameter vascular grafts to overcome the drawbacks of traditional methods used for treatment of widespread cardiovascular diseases. Vascular tissue engineering (VTE) is a promising approach that can be utilized to develop viable vascular grafts by in vitro seeding of functional cells onto a scaffold allowing them to attach, proliferate and differentiate. To achieve this purpose, the scaffold should provide cells with the initial necessary extracellular matrix environment and structure until being able to reconstruct the required vascular tissue. Therefore, producing scaffolds with suitable features is crucial for guiding cells properly to develop the desired tissue-engineered vascular grafts for clinical applications. The main objective of this work is fabrication and characterization of tubular small-diameter ( < 6 mm) bilayered scaffolds for VTE. The scaffolds were prepared via mixing electrospinning approach of biodegradable poly(ε-caprolactone) (PCL) polymer – due to its favorable physicochemical properties – to mimic the natural environment-extracellular matrix. Firstly, tubular nanofibrous construct with inner diameter of 3, 4 or 5 mm was electrospun as inner layer, and secondly, microfibrous construct was electrospun as outer layer directly on the first produced inner layer. To improve the biological properties of PCL, a group of the electrospun scaffolds was immersed in type-1 collagen solution. The morphology and structure of the resulting fibrous scaffolds were investigated by scanning electron microscope. The electrospun nanofibrous inner layer contained fibers measuring 219±35 nm in diameter, while the electrospun microfibrous outer layer contained fibers measuring 1011 ± 150 nm. Furthermore, mechanical, thermal and physical tests were conducted with both electrospun bilayered scaffold types where revealed improved properties. Biological investigations using endothelial, smooth muscle and fibroblast cell line showed good biocompatibility of both tested electrospun scaffolds. Better attachment and proliferation were obviously found when cells were cultured on the scaffolds immersed with collagen due to increasing the hydrophilicity of the PCL. The easy, inexpensive and versatile electrospinning approach used in this work was able to successfully produce double layered tubular elastic structures containing both nanofibers and microfibers to imitate the native vascular structure. The PCL – as a suitable and approved biomaterial for many biomedical and tissue engineering applications – can ensure favorable mechanical properties of scaffolds used for VTE. The VTE approach using electrospun bilayered scaffolds offers optimal solutions and holds significant promises for treatment of many cardiovascular diseases.

Keywords: electrospinning, poly(ε-caprolactone) (PCL), tissue-engineered vascular graft, tubular bilayered scaffolds, vascular cells

Procedia PDF Downloads 282
5207 Optimization of Sodium Lauryl Surfactant Concentration for Nanoparticle Production

Authors: Oluwatoyin Joseph Gbadeyan, Sarp Adali, Bright Glen, Bruce Sithole

Abstract:

Sodium lauryl surfactant concentration optimization, for nanoparticle production, provided the platform for advanced research studies. Different concentrations (0.05 %, 0.1 %, and 0.2 %) of sodium lauryl surfactant was added to snail shells powder during milling processes for producing CaCO3 at smaller particle size. Epoxy nanocomposites prepared at filler content 2 wt.% synthesized with different volumes of sodium lauryl surfactant were fabricated using a conventional resin casting method. Mechanical properties such as tensile strength, stiffness, and hardness of prepared nanocomposites was investigated to determine the effect of sodium lauryl surfactant concentration on nanocomposite properties. It was observed that the loading of the synthesized nano-calcium carbonate improved the mechanical properties of neat epoxy at lower concentrations of sodium lauryl surfactant 0.05 %. Meaningfully, loading of achatina fulica snail shell nanoparticles manufactures, with small concentrations of sodium lauryl surfactant 0.05 %, increased the neat epoxy tensile strength by 26%, stiffness by 55%, and hardness by 38%. Homogeneous dispersion facilitated, by the addition of sodium lauryl surfactant during milling processes, improved mechanical properties. Research evidence suggests that nano-CaCO3, synthesized from achatina fulica snail shell, possesses suitable reinforcement properties that can be used for nanocomposite fabrication. The evidence showed that adding small concentrations of sodium lauryl surfactant 0.05 %, improved dispersion of nanoparticles in polymetrix material that provided mechanical properties improvement.

Keywords: sodium lauryl surfactant, mechanical properties , achatina fulica snail shel, calcium carbonate nanopowder

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5206 Lean Commercialization: A New Dawn for Commercializing High Technologies

Authors: Saheed A. Gbadegeshin

Abstract:

Lean Commercialization (LC) is a transformation of new technologies and knowledge to products and services through application of lean/agile principle. This principle focuses on how resources can be minimized on development, manufacturing, and marketing new products/services, which can be accepted by customers. To understand how the LC has been employed by the technology-based companies, a case study approach was employed by interviewing the founders, observing their high technologies, and interviewing the commercialization experts. Two serial entrepreneurs were interviewed in 2012, and their commercialized technologies were monitored from 2012 till 2016. Some results were collected, but to validate the commercialization strategies of these entrepreneurs, four commercialization experts were interviewed in 2017. Initial results, observation notes, and experts’ opinions were analyzed qualitatively. The final findings showed that the entrepreneurs applied the LC unknowingly, and the experts were aware of the LC. Similarly, the entrepreneurs used the LC due to the financial constraints, and their need for success. Additionally, their commercialization practices revealed that LC appeared to be one of their commercialization strategies. Thus, their practices were analyzed, and a framework was developed. Furthermore, the experts noted that LC is a new dawn, which technologists and scientists need to consider for their high technology commercialization. This article contributes to the theory and practice of commercialization. Theoretically, the framework adds value to the commercialization discussion. And, practically the framework can be used by the technology entrepreneurs (technologists and scientists), technology-based enterprises, and technology entrepreneurship educators as a guide in their commercialization adventures.

Keywords: lean commercialization, high technologies, lean start-up, technology-based companies

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5205 Numerical Simulation of Truck Collision with Road Blocker

Authors: Engin Metin Kaplan, Kemal Yaman

Abstract:

In this study, the crash of a medium heavy vehicle onto a designed Road blocker (vehicle barrier) is studied numerically. Structural integrity of the Road blocker is studied by nonlinear dynamic methods under the loading conditions which are defined in the standards. NASTRAN® and LS-DYNA® which are commercial software are used to solve the problem. Outer geometry determination, alignment of the inner part and material properties of the road blocker are studied linearly to yield design parameters. Best design parameters are determined to achieve the most structurally optimized road blocker. Strain and stress values of the vehicle barrier are obtained by solving the partial differential equations.

Keywords: vehicle barrier, truck collision, road blocker, crash analysis

Procedia PDF Downloads 466
5204 Use of EPR in Experimental Mechanics

Authors: M. Sikoń, E. Bidzińska

Abstract:

An attempt to apply EPR (Electron Paramagnetic Resonance) spectroscopy to experimental analysis of the mechanical state of the loaded material is considered in this work. Theory concerns the participation of electrons in transfer of mechanical action. The model of measurement is shown by applying classical mechanics and quantum mechanics. Theoretical analysis is verified using EPR spectroscopy twice, once for the free spacemen and once for the mechanical loaded spacemen. Positive results in the form of different spectra for free and loaded materials are used to describe the mechanical state in continuum based on statistical mechanics. Perturbation of the optical electrons in the field of the mechanical interactions inspires us to propose new optical properties of the materials with mechanical stresses.

Keywords: Cosserat medium, EPR spectroscopy, optical active electrons, optical activity

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5203 The New Face of TV: An Exploratory Study on the Effects of Snapchat on TV Ratings in Kuwait

Authors: Bashaiar Alsanaa

Abstract:

The advent of new forms of media has always led to a change in the way existing media deliver content. No medium has been replaced by another yet over the course of history. Whether this fact changes with the introduction of new age technology and social media remains to be seen. Snapchat may be the first application, to seriously challenge TV. It is perhaps the new face of television. The individualistic nature of Snapchat, whereby users control who, when, and in what order to watch, assesses user freedom from traditional broadcasters’ control. This study aims to fill the void in research conducted around such topic. The research explores how Snapchat maybe slowly but replacing TV. The study surveys users in Kuwait in order to present an overview of the topic. It also draws a framework through which implications and suggestions for future research may be discussed to better serve the advancement of media research.

Keywords: Kuwait, media, Snapchat, television

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5202 Analysis of the Reasons behind the Deteriorated Standing of Engineering Companies during the Financial Crisis

Authors: Levan Sabauri

Abstract:

In this paper, we discuss the deteriorated standing of engineering companies, some of the reasons behind it and the problems facing engineering enterprises during the financial crisis. We show the part that financial analysis plays in the detection of the main factors affecting the standing of a company, classify internal problems and the reasons influencing efficiency thereof. The publication contains the analysis of municipal engineering companies in post-Soviet transitional economies. In the wake of the 2008 world financial crisis the issue became even more poignant. It should be said though that even before the problem had been no less acute for some post-Soviet states caught up in a lengthy transitional period. The paper highlights shortcomings in the management of transportation companies, with new, more appropriate methods suggested. In analyzing the financial stability of a company, three elements need to be considered: current assets, investment policy and structural management of the funding sources leveraging the stability, should be focused on. Inappropriate management of the three may create certain financial problems, with timely and accurate detection thereof being an issue in terms of improved standing of an enterprise. In this connection, the publication contains a diagram reflecting the reasons behind the deteriorated financial standing of a company, as well as a flow chart thereof. The main reasons behind low profitability are also discussed.

Keywords: efficiency, financial management, financial analysis funding structure, financial sustainability, investment policy, profitability, solvency, working capital

Procedia PDF Downloads 295
5201 Some Issues with Extension of an HPC Cluster

Authors: Pil Seong Park

Abstract:

Homemade HPC clusters are widely used in many small labs, because they are easy to build and cost-effective. Even though incremental growth is an advantage of clusters, it results in heterogeneous systems anyhow. Instead of adding new nodes to the cluster, we can extend clusters to include some other Internet servers working independently on the same LAN, so that we can make use of their idle times, especially during the night. However extension across a firewall raises some security problems with NFS. In this paper, we propose a method to solve such a problem using SSH tunneling, and suggest a modified structure of the cluster that implements it.

Keywords: extension of HPC clusters, security, NFS, SSH tunneling

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5200 Dry Modifications of PCL/Chitosan/PCL Tissue Scaffolds

Authors: Ozan Ozkan, Hilal Turkoglu Sasmazel

Abstract:

Natural polymers are widely used in tissue engineering applications, because of their biocompatibility, biodegradability and solubility in the physiological medium. On the other hand, synthetic polymers are also widely utilized in tissue engineering applications, because they carry no risk of infectious diseases and do not cause immune system reaction. However, the disadvantages of both polymer types block their individual usages as tissue scaffolds efficiently. Therefore, the idea of usage of natural and synthetic polymers together as a single 3D hybrid scaffold which has the advantages of both and the disadvantages of none has been entered to the literature. On the other hand, even though these hybrid structures support the cell adhesion and/or proliferation, various surface modification techniques applied to the surfaces of them to create topographical changes on the surfaces and to obtain reactive functional groups required for the immobilization of biomolecules, especially on the surfaces of synthetic polymers in order to improve cell adhesion and proliferation. In a study presented here, to improve the surface functionality and topography of the layer by layer electrospun 3D poly-epsilon-caprolactone/chitosan/poly-epsilon-caprolactone hybrid tissue scaffolds by using atmospheric pressure plasma method, thus to improve cell adhesion and proliferation of these tissue scaffolds were aimed. The formation/creation of the functional hydroxyl and amine groups and topographical changes on the surfaces of scaffolds were realized by using two different atmospheric pressure plasma systems (nozzle type and dielectric barrier discharge (DBD) type) carried out under different gas medium (air, Ar+O2, Ar+N2). The plasma modification time and distance for the nozzle type plasma system as well as the plasma modification time and the gas flow rate for DBD type plasma system were optimized with monitoring the changes in surface hydrophilicity by using contact angle measurements. The topographical and chemical characterizations of these modified biomaterials’ surfaces were carried out with SEM and ESCA, respectively. The results showed that the atmospheric pressure plasma modifications carried out with both nozzle type plasma and DBD plasma caused topographical and functionality changes on the surfaces of the layer by layer electrospun tissue scaffolds. However, the shelf life studies indicated that the hydrophilicity introduced to the surfaces was mainly because of the functionality changes. Therefore, according to the optimized results, samples treated with nozzle type air plasma modification applied for 9 minutes from a distance of 17 cm and Ar+O2 DBD plasma modification applied for 1 minute under 70 cm3/min O2 flow rate were found to have the highest hydrophilicity compared to pristine samples.

Keywords: biomaterial, chitosan, hybrid, plasma

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5199 Designing a Legal Framework for Social Innovation

Authors: Prapin Nuchpiam

Abstract:

The importance of social innovation has become increasingly significant as the process of developing effective solutions to social problems and being a force of change for people’s better quality of life. In order to promote social innovation, active collaboration between government, business organizations, and the civil society sector is needed. A proper legal framework also plays an important role in building the social innovation ecosystem. Currently, there is no specific law designed for social innovation or a so-called “social innovation law”. One of the legal frameworks for social innovation is the development of hybrid legal forms for social enterprises such as the UK’s Community Interest Company (CIC), the US’s Low-Profit Limited Liability Company (L3C) and the US’s Benefit Corporation (B-Corp), among others. This is because social enterprise is recognized as an organizational form of social innovation with its aim for social benefit goals and the achievement of financial sustainability. Nonetheless, there has been a debate over the differences and similarities between social innovation and social enterprise. Thus, social enterprise law might not fit well with social innovation, resulting in a search for a legal framework specially designed for social innovation. This paper aims to study the interrelationship between social innovation, social enterprise, and the role of law to see whether we need a specific law for social innovation. If so, what should such a legal framework look like? The paper will provide a critical analysis of innovative legal forms for social enterprise as a type of social innovation law. A proper legal framework for social innovation could help promote the sector, which could result in finding new solutions to social problems. It will also bring about a greater common understanding of the exciting development of legal scholarship in this way, which will, in turn, serve as a productive basis or direction for further research on this increasingly important topic.

Keywords: social innovation, social enterprise, legal framework, regulation

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5198 Challenges and Opportunities of Utilization of Social Media by Business Education Students in Nigeria Universities

Authors: Titus Amodu Umoru

Abstract:

The global economy today is full of sophistication. All over the world, business and marketing practices are undergoing an unprecedented transformation. In realization of this fact, the federal government of Nigeria has put in place a robust transformation agenda in order to put Nigeria in a better position to be a competitive player and in the process transform all sectors of its economy. New technologies, especially the internet, are the driving force behind this transformation. However, technology has inadvertently affected the way businesses are done thus necessitating the acquisition of new skills. In developing countries like Nigeria, citizens are still battling with effective application of those technologies. Obviously, students of business education need to acquire relevant business knowledge to be able to transit into the world of work on graduation from school and compete favourably in the labour market. Therefore, effective utilization of social media by both teachers and students can help extensively in empowering students with the needed skills. Social media which is described as a group of internet-based applications that build on the ideological foundations of Web 2.0, and which allow the creation and exchange of user-generated content, if incorporated into the classroom experience may be the needed answer to unemployment and poverty in Nigeria as beneficiaries can easily connect with existing and potential enterprises and customers, engage with them and reinforce mutual business benefits. Challenges and benefits of social media use in education in Nigeria universities were revealed in this study.

Keywords: business education, challenges, opportunities, utilization, social media

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5197 Comparative Analysis of Mechanical Properties of Paddy Rice for Different Variety-Moisture Content Interactions

Authors: Johnson Opoku-Asante, Emmanuel Bobobee, Joseph Akowuah, Eric Amoah Asante

Abstract:

In recent years, the issue of postharvest losses has become a serious concern in Sub-Saharan Africa. Postharvest technology development and adaptation need urgent attention, particularly for small and medium-scale rice farmers in Africa. However, to better develop any postharvest technology, knowledge of the mechanical properties of different varieties of paddy rice is vital. There is also the issue of the development of new rice cultivars. The objectives of this research are to (1) determine the mechanical properties of the selected paddy rice varieties at varying moisture content. (2) conduct a comparative analysis of the mechanical properties of selected rice paddy for different variety-moisture content interactions. (3) determine the significant statistical differences between the mean values of the various variety-moisture content interactions The mechanical properties of AGRA rice, CRI-Amankwatia, CRI-Enapa and CRI-Dartey, four local varieties developed by Crop Research Institute of Ghana are compared at 11.5%, 13.0% and 16.5% dry basis moisture content. The mechanical properties measured are Sphericity, Aspect ratio, Grain mass, 1000 Grain mass, Bulk Density, True Density, Porosity and Angle of Repose. Samples were collected from the Kwadaso Agric College of the CRI in Kumasi. The samples were threshed manually and winnowed before conducting the experiment. The moisture content was determined on a dry basis using the Moistex Screw-Type Digital Grain Moisture Meter. Other equipment used for data collection were venire calipers and Citizen electronic scale. A 4×3 factorial arrangement was used in a completely randomized design in three replications. Tukey's HSD comparisons test was conducted during data analysis to compare all possible pairwise combinations of the various varieties’ moisture content interaction. From the results, it was concluded that Sphericity recorded 0.391 mm³ to 0.377 mm³ for CRI-Dartey at 16.5% and CRI-Enapa at 13.5%, respectively, whereas Aspect Ratio recorded 0.298 mm³ to 0.269 mm³ for CRI-Dartey at 16.5% and CRI-Enapa at 13.5% respectively. For grain mass, AGRA rice at 13.0% also recorded 0.0312 g as the highest score and CRI-Enapa at 13.0% obtained 0.0237 as the lowest score. For the GM1000, it was observed that it ranges from 29.33 g for CRI-Amankwatia at 16.5% moisture content to 22.54 g for CRI-Enapa at 16.5% interactions. Bulk Density ranged from 654.0 kg/m³ to 422.9 kg/m³ for CRI-Amankwatia at 16.5% and CRI-Enapa at 11.5% as the highest and lowest recordings, respectively. It was also observed that the true Density ranges from 1685.8 kg/m3 for AGRA rice at 13.0% moisture content to 1352.5 kg/m³ for CRI-Enapa at 16.5% interactions. In the case of porosity, CRI-Enapa at 11.5% received the highest score of 70.83% and CRI-Amankwatia at 16.5 received the lowest score of 55.88%. Finally, in the case of Angle of Repose, CRI-Amankwatia at 16.5% recorded the highest score of 47.3o and CRI-Enapa at 11.5% recorded the least score of 34.27o. In all cases, the difference in mean value was less than the LSD. This indicates that there were no significant statistical differences between their mean values, indicating that technologies developed and adapted for one variety can equally be used for all the other varieties.

Keywords: angle of repose, aspect ratio, bulk density, porosity, sphericity, mechanical properties

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5196 Stability Evaluation on Accumulation Body of Reservoir Slope in Rumei Hydropower Station, China

Authors: Yaofei Jiang, Liangqing Wang, Yanjun Xu

Abstract:

In recent years, geological explorations have been carried out on the Rumei hydropower station, China. After preliminary analysis of results, the mainly problem of slope in reservoir area is about the stability of accumulation body. It is found that there are 23 accumulations in various sizes in the reservoir area, and most of them are unfavorable geological bodies. Three typical (No. 1, 7, 17) accumulation body slopes were selected as subjects to investigate the stability of the slopes. Take No. 1 accumulation body slope as an example and basic geological condition investigation and formation mechanism analysis were carried out to study the stability and geological analysis of engineering influence of the slope. The accumulation body in the research area distributes along the river with natural slope of 32° ~ 37° which is the natural angle of repose of gravel. The formation mechanism is analyzed based on the composition and structure of the accumulation body. The middle and lower part of the body is dense full of gravel soil mixed with a small amount of sand gravel which is stable. In the upper part, gravel soil is interbedded with bad cemented gravel which as a weak surface is not conducive to slope stability. Under the natural condition before storing water, the underground water level is deep buried, mainly distributed in the bedrock, and the surface and groundwater discharge conditions of the accumulation body are good, which is beneficial to the stability of slope. The safety coefficient calculated by the limit equilibrium method is 1.14, which indicates the slope is basically stable. However, the safety coefficient drops to 1.02 when the normal storage level is 2895m, which is in a dangerous state. The accumulation body will be destabilized by a small-area instability to large-scale or overall instability.

Keywords: accumulation body slope, stability evaluation, geological engineering investigation, effect of storing water

Procedia PDF Downloads 157
5195 Teaching Speaking Skills to Adult English Language Learners through ALM

Authors: Wichuda Kunnu, Aungkana Sukwises

Abstract:

Audio-lingual method (ALM) is a teaching approach that is claimed that ineffective for teaching second/foreign languages. Because some linguists and second/foreign language teachers believe that ALM is a rote learning style. However, this study is done on a belief that ALM will be able to solve Thais’ English speaking problem. This paper aims to report the findings on teaching English speaking to adult learners with an “adapted ALM”, one distinction of which is to use Thai as the medium language of instruction. The participants are consisted of 9 adult learners. They were allowed to speak English more freely using both the materials presented in the class and their background knowledge of English. At the end of the course, they spoke English more fluently, more confidently, to the extent that they applied what they learnt both in and outside the class.

Keywords: teaching English, audio lingual method, cognitive science, psychology

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5194 Disruptive Innovation in Low-Income Countries: The Role of the Sharing Economy in Shaping the People Transportation Market in Nigeria

Authors: D. Tappi

Abstract:

In the past decades, the idea of innovation moved from being considered the result of development to being seen as its means. Innovation and its diffusion are indeed keys to the development and economic catch-up of a country. However, the process of diffusing existing innovation in low income countries has demonstrated dependent on inadequate infrastructures and institutions. The paper examines the role of disruptive innovation in bridging the technology gap between high- and low-income countries, overcoming the lack in infrastructures and institutions. In particular, the focus of this paper goes to the role of disruptive innovation in people transportation in Nigeria. Uber, Taxify, and Smartcab are covering a small and interesting market that was underserved, between the high-end private driver markets, the personal car owners and the low-priced traditional cab and the Keke (tricycle). Indeed the small Nigerian middle class and international community have found in the sharing people transportation market a safe, reasonably priced means of transportation in Nigerian big cities. This study uses mainly qualitative data collection methods in the form of semi-structured interviews with major players and users and quantitative data analysis in the form of a survey among users in order to assess the role of these new transportation modes in shaping the market and even creating a new niche. This paper shows how the new sharing economy in people transportation is creating new solutions to old problems as well as creating new challenges for both the existing market players and institutions. By doing so, the paper shows how disruptive innovations applied to low income countries, not only can overcome the lacking infrastructure problem but could also help bridge the technology gap between those and high income countries. This contribution proves that it is indeed exactly because the market presents these obstacles that disruptive innovations can succeed in countries such as Nigeria.

Keywords: development, disruptive innovation, sharing economy, technology gap

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5193 Evolution of Approaches to Cost Calculation in the Conditions of the Modern Russian Economy

Authors: Elena Tkachenko, Vladimir Kokh, Alina Osipenko, Vladislav Surkov

Abstract:

The modern period of development of Russian economy is fraught with a number of problems related to limitations in the use of traditional planning and financial management tools. Restrictions in the use of foreign software when performing an order of the Russian Government, on the one hand, and sanctions limiting the support of the major ERP and MRP II systems in the Russian Federation, on the other hand, entail the necessity to appeal to the basics of developing budgeting and analysis systems for industrial enterprises. Thus, cost calculation theory becomes the theoretical foundation for the development of industrial cost management systems. Based on the foregoing, it would be fair to make an assumption that the development of a working managerial accounting model on an industrial enterprise using an automated enterprise resource management system should rest upon the concept of the inevitability of alterations of business processes. On the other hand, optimized business processes make the architecture of financial analytics more transparent and permit the use of all the benefits of data cubes. The metrics and indicator slices provide online assessment of the state of key business processes at a given moment of time, which improves the quality of managerial decisions considerably. Therefore, the bilateral sanctions situation boosted the development of corporate business analytics and took industrial companies to the next level of understanding of business processes.

Keywords: cost culculation, ERP, OLAP, modern Russian economy

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5192 Investigating the Factors Affecting the Innovation of Firms in Metropolitan Regions: The Case of Mashhad Metropolitan Region, Iran

Authors: Hashem Dadashpoor, Sadegh Saeidi Shirvan

Abstract:

While with the evolution of the economy towards a knowledge-based economy, innovation is a requirement for metropolitan regions, the adoption of an open innovation strategy is an option and a requirement for many industrial firms in these regions. Studies show that investing in research and development units cannot alone increase innovation. Within the framework of the theory of learning regions, this gap, which scholars call it the ‘innovation gap’, is filled with regional features of firms. This paper attempts to investigate the factors affecting the open innovation of firms in metropolitan regions, and it searches for these in territorial innovation models and, in particular, the theory of learning regions. In the next step, the effect of identified factors which is considered as regional learning factors in this research is analyzed on the innovation of sample firms by SPSS software using multiple linear regression. The case study of this research is constituted of industrial enterprises from two groups of food industry and auto parts in Toos industrial town in Mashhad metropolitan region. For data gathering of this research, interviews were conducted with managers of industrial firms using structured questionnaires. Based on this study, the effect of factors such as size of firms, inter-firm competition, the use of local labor force and institutional infrastructures were significant in the innovation of the firms studied, and 44% of the changes in the firms’ innovation occurred as a result of the change in these factors.

Keywords: regional knowledge networks, learning regions, interactive learning, innovation

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5191 Vortex Flows under Effects of Buoyant-Thermocapillary Convection

Authors: Malika Imoula, Rachid Saci, Renee Gatignol

Abstract:

A numerical investigation is carried out to analyze vortex flows in a free surface cylinder, driven by the independent rotation and differentially heated boundaries. As a basic uncontrolled isothermal flow, we consider configurations which exhibit steady axisymmetric toroidal type vortices which occur at the free surface; under given rates of the bottom disk uniform rotation and for selected aspect ratios of the enclosure. In the isothermal case, we show that sidewall differential rotation constitutes an effective kinematic means of flow control: the reverse flow regions may be suppressed under very weak co-rotation rates, while an enhancement of the vortex patterns is remarked under weak counter-rotation. However, in this latter case, high rates of counter-rotation reduce considerably the strength of the meridian flow and cause its confinement to a narrow layer on the bottom disk, while the remaining bulk flow is diffusion dominated and controlled by the sidewall rotation. The main control parameters in this case are the rotational Reynolds number, the cavity aspect ratio and the rotation rate ratio defined. Then, the study proceeded to consider the sensitivity of the vortex pattern, within the Boussinesq approximation, to a small temperature gradient set between the ambient fluid and an axial thin rod mounted on the cavity axis. Two additional parameters are introduced; namely, the Richardson number Ri and the Marangoni number Ma (or the thermocapillary Reynolds number). Results revealed that reducing the rod length induces the formation of on-axis bubbles instead of toroidal structures. Besides, the stagnation characteristics are significantly altered under the combined effects of buoyant-thermocapillary convection. Buoyancy, induced under sufficiently high Ri, was shown to predominate over the thermocapillay motion; causing the enhancement (suppression) of breakdown when the rod is warmer (cooler) than the ambient fluid. However, over small ranges of Ri, the sensitivity of the flow to surface tension gradients was clearly evidenced and results showed its full control over the occurrence and location of breakdown. In particular, detailed timewise evolution of the flow indicated that weak thermocapillary motion was sufficient to prevent the formation of toroidal patterns. These latter detach from the surface and undergo considerable size reduction while moving towards the bulk flow before vanishing. Further calculations revealed that the pattern reappears with increasing time as steady bubble type on the rod. However, in the absence of the central rod and also in the case of small rod length l, the flow evolved into steady state without any breakdown.

Keywords: buoyancy, cylinder, surface tension, toroidal vortex

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5190 Interorganizational Relationships in the Brazilian Milk Production Chain

Authors: Marcelo T. Okano, Oduvaldo Vendrametto, Osmildo S. Santos, Marcelo E. Fernandes, Heide Landi

Abstract:

The literature on the interorganizational relationship between companies and organizations has increased in recent years, but there are still doubts about the various settings. The interorganizational networks are important in economic life, the fact facilitate the complex interdependence between transactional and cooperative organizations. A need identified in the literature is the lack of indicators to measure and identify the types of existing networks. The objective of this research is to examine the interorganizational relationships of two milk chains through indicators proposed by the theories of the four authors, characterizing them as network or not and what the benefits obtained by the chain organization. To achieve the objective of this work was carried out a survey of milk producers in two regions of the state of São Paulo. To collect the information needed for the analysis, exploratory research, qualitative nature was used. The research instrument of this work consists of a roadmap of semistructured interviews with open questions. Some of the answers were directed by the interviewer in the form of performance notes aimed at detecting the degree of importance, according to the perception of intensity to that regard. The results showed that interorganizational relationships are small and largely limited to the sale of milk or dairy cooperatives. These relationships relate only to trade relations between the owner and purchaser of milk. But when the producers are organized in associations or networks, interorganizational relationships and increase benefits for all participants in the network. The various visits and interviews in several dairy farms in the regions of São Pau-lo (indicated that the inter-relationships are small and largely limited to the sale of milk to cooperatives or dairy. These relationships refer only to trade relations between the owner and the purchaser of milk. But when the producers are organized in associations or networks, interorganizational relationships increase and bring benefits to all participants in the network.

Keywords: interorganizational networks, dairy chain, interorganizational system, São Pau-lo

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5189 Evaluation of Kabul BRT Route Network with Application of Integrated Land-use and Transportation Model

Authors: Mustafa Mutahari, Nao Sugiki, Kojiro Matsuo

Abstract:

The four decades of war, lack of job opportunities, poverty, lack of services, and natural disasters in different provinces of Afghanistan have contributed to a rapid increase in the population of Kabul, the capital city of Afghanistan. Population census has not been conducted since 1979, the first and last population census in Afghanistan. However, according to population estimations by Afghan authorities, the population of Kabul has been estimated at more than 4 million people, whereas the city was designed for two million people. Although the major transport mode of Kabul residents is public transport, responsible authorities within the country failed to supply the required means of transportation systems for the city. Besides, informal resettlement, lack of intersection control devices, presence of illegal vendors on streets, presence of illegal and unstandardized on-street parking and bus stops, driver`s unprofessional behavior, weak traffic law enforcement, and blocked roads and sidewalks have contributed to the extreme traffic congestion of Kabul. In 2018, the government of Afghanistan approved the Kabul city Urban Design Framework (KUDF), a vision towards the future of Kabul, which provides strategies and design guidance at different scales to direct urban development. Considering traffic congestion of the city and its budget limitations, the KUDF proposes a BRT route network with seven lines to reduce the traffic congestion, and it is said to facilitate more than 50% of Kabul population to benefit from this service. Based on the KUDF, it is planned to increase the BRT mode share from 0% to 17% and later to 30% in medium and long-term planning scenarios, respectively. Therefore, a detailed research study is needed to evaluate the proposed system before the implementation stage starts. The integrated land-use transport model is an effective tool to evaluate the Kabul BRT because of its future assessment capabilities that take into account the interaction between land use and transportation. This research aims to analyze and evaluate the proposed BRT route network with the application of an integrated land-use and transportation model. The research estimates the population distribution and travel behavior of Kabul within small boundary scales. The actual road network and land-use detailed data of the city are used to perform the analysis. The BRT corridors are evaluated not only considering its impacts on the spatial interactions in the city`s transportation system but also on the spatial developments. Therefore, the BRT are evaluated with the scenarios of improving the Kabul transportation system based on the distribution of land-use or spatial developments, planned development typology and population distribution of the city. The impacts of the new improved transport system on the BRT network are analyzed and the BRT network is evaluated accordingly. In addition, the research also focuses on the spatial accessibility of BRT stops, corridors, and BRT line beneficiaries, and each BRT stop and corridor are evaluated in terms of both access and geographic coverage, as well.

Keywords: accessibility, BRT, integrated land-use and transport model, travel behavior, spatial development

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5188 Disaster Capitalism, Charter Schools, and the Reproduction of Inequality in Poor, Disabled Students: An Ethnographic Case Study

Authors: Sylvia Mac

Abstract:

This ethnographic case study examines disaster capitalism, neoliberal market-based school reforms, and disability through the lens of Disability Studies in Education. More specifically, it explores neoliberalism and special education at a small, urban charter school in a large city in California and the (re)production of social inequality. The study uses Sociology of Special Education to examine the ways in which special education is used to sort and stratify disabled students. At a time when rhetoric surrounding public schools is framed in catastrophic and dismal language in order to justify the privatization of public education, small urban charter schools must be examined to learn if they are living up to their promise or acting as another way to maintain economic and racial segregation. The study concludes that neoliberal contexts threaten successful inclusive education and normalize poor, disabled students’ continued low achievement and poor post-secondary outcomes. This ethnographic case study took place at a small urban charter school in a large city in California. Participants included three special education students, the special education teacher, the special education assistant, a regular education teacher, and the two founders and charter writers. The school claimed to have a push-in model of special education where all special education students were fully included in the general education classroom. Although presented as fully inclusive, some special education students also attended a pull-out class called Study Skills. The study found that inclusion and neoliberalism are differing ideologies that cannot co-exist. Successful inclusive environments cannot thrive while under the influences of neoliberal education policies such as efficiency and cost-cutting. Additionally, the push for students to join the global knowledge economy means that more and more low attainers are further marginalized and kept in poverty. At this school, neoliberal ideology eclipsed the promise of inclusive education for special education students. This case study has shown the need for inclusive education to be interrogated through lenses that consider macro factors, such as neoliberal ideology in public education, as well as the emerging global knowledge economy and increasing income inequality. Barriers to inclusion inside the school, such as teachers’ attitudes, teacher preparedness, and school infrastructure paint only part of the picture. Inclusive education is also threatened by neoliberal ideology that shifts the responsibility from the state to the individual. This ideology is dangerous because it reifies the stereotypes of disabled students as lazy, needs drains on already dwindling budgets. If these stereotypes persist, inclusive education will have a difficult time succeeding. In order to more fully examine the ways in which inclusive education can become truly emancipatory, we need more analysis on the relationship between neoliberalism, disability, and special education.

Keywords: case study, disaster capitalism, inclusive education, neoliberalism

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5187 Techno Economic Analysis of CAES Systems Integrated into Gas-Steam Combined Plants

Authors: Coriolano Salvini

Abstract:

The increasing utilization of renewable energy sources for electric power production calls for the introduction of energy storage systems to match the electric demand along the time. Although many countries are pursuing as a final goal a “decarbonized” electrical system, in the next decades the traditional fossil fuel fed power plant still will play a relevant role in fulfilling the electric demand. Presently, such plants provide grid ancillary services (frequency control, grid balance, reserve, etc.) by adapting the output power to the grid requirements. An interesting option is represented by the possibility to use traditional plants to improve the grid storage capabilities. The present paper is addressed to small-medium size systems suited for distributed energy storage. The proposed Energy Storage System (ESS) is based on a Compressed Air Energy Storage (CAES) integrated into a Gas-Steam Combined Cycle (GSCC) or a Gas Turbine based CHP plants. The systems can be incorporated in an ex novo built plant or added to an already existing one. To avoid any geological restriction related to the availability of natural compressed air reservoirs, artificial storage is addressed. During the charging phase, electric power is absorbed from the grid by an electric driven intercooled/aftercooled compressor. In the course of the discharge phase, the compressed stored air is sent to a heat transfer device fed by hot gas taken upstream the Heat Recovery Steam Generator (HRSG) and subsequently expanded for power production. To maximize the output power, a staged reheated expansion process is adopted. The specific power production related to the kilogram per second of exhaust gas used to heat the stored air is two/three times larger than that achieved if the gas were used to produce steam in the HRSG. As a result, a relevant power augmentation is attained with respect to normal GSCC plant operations without additional use of fuel. Therefore, the excess of output power can be considered “fuel free” and the storage system can be compared to “pure” ESSs such as electrochemical, pumped hydro or adiabatic CAES. Representative cases featured by different power absorption, production capability, and storage capacity have been taken into consideration. For each case, a technical optimization aimed at maximizing the storage efficiency has been carried out. On the basis of the resulting storage pressure and volume, number of compression and expansion stages, air heater arrangement and process quantities found for each case, a cost estimation of the storage systems has been performed. Storage efficiencies from 0.6 to 0.7 have been assessed. Capital costs in the range of 400-800 €/kW and 500-1000 €/kWh have been estimated. Such figures are similar or lower to those featuring alternative storage technologies.

Keywords: artificial air storage reservoir, compressed air energy storage (CAES), gas steam combined cycle (GSCC), techno-economic analysis

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5186 Unification of Lactic Acid Bacteria and Aloe Vera for Healthy Gut

Authors: Pavitra Sharma, Anuradha Singh, Nupur Mathur

Abstract:

There exist more than 100 trillion bacteria in the digestive system of human-beings. Such bacteria are referred to as gut microbiota. Gut microbiota comprises around 75% of our immune system. The bacteria that comprise the gut microbiota are unique to every individual and their composition keeps changing with time owing to factors such as the host’s age, diet, genes, environment, and external medication. Of these factors, the variable easiest to control is one’s diet. By modulating one’s diet, one can ensure an optimal composition of the gut microbiota yielding several health benefits. Prebiotics and probiotics are two compounds that have been considered as viable options to modulate the host’s diet. Prebiotics are basically plant products that support the growth of good bacteria in the host’s gut. Examples include garden asparagus, aloe vera etc. Probiotics are living microorganisms that exist in our intestines and play an integral role in promoting digestive health and supporting our immune system in general. Examples include yogurt, kimchi, kombucha etc. In the context of modulating the host’s diet, the key attribute of prebiotics is that they support the growth of probiotics. By developing the right combination of prebiotics and probiotics, food products or supplements can be created to enhance the host’s health. An effective combination of prebiotics and probiotics that yields health benefits to the host is referred to as synbiotics. Synbiotics comprise of an optimal proportion of prebiotics and probiotics, their application benefits the host’s health more than the application of prebiotics and probiotics used in isolation. When applied to food supplements, synbiotics preserve the beneficial probiotic bacteria during storage period and during the bacteria’s passage through the intestinal tract. When applied to the gastrointestinal tract, the composition of the synbiotics assumes paramount importance. Reason being that for synbiotics to be effective in the gastrointestinal tract, the chosen probiotic must be able to survive in the stomach’s acidic environment and manifest tolerance towards bile and pancreatic secretions. Further, not every prebiotic stimulates the growth of a particular probiotic. The prebiotic chosen should be one that not only maintains 2 balance in the host’s digestive system, but also provides the required nutrition to probiotics. Hence in each application of synbiotics, the prebiotic-probiotic combination needs to be carefully selected. Once the combination is finalized, the exact proportion of prebiotics and probiotics to be used needs to be considered. When determining this proportion, only that amount of a prebiotic should be used that activates metabolism of the required number of probiotics. It was observed that while probiotics are active is both the small and large intestine, the effect of prebiotics is observed primarily in the large intestine. Hence in the host’s small intestine, synbiotics are likely to have the maximum efficacy. In small intestine, prebiotics not only assist in the growth of probiotics, but they also enable probiotics to exhibit a higher tolerance to pH levels, oxygenation, and intestinal temperature

Keywords: microbiota, probiotics, prebiotics, synbiotics

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5185 Nanoparticle Induced Neurotoxicity Mediated by Mitochondria

Authors: Nandini Nalika, Suhel Parvez

Abstract:

Nanotechnology has emerged to play a vital role in developing all through the industrial world with an immense production of nanomaterials including nanoparticles (NPs). Many toxicological studies have confirmed that due to unique small size and physico-chemical properties of NPs (1-100nm), they can be potentially hazardous. Metallic NPs of small size have been shown to induce higher levels of cellular oxidative stress and can easily pass through the Blood Brain Barrier (BBB) and significantly accumulate in brain. With the wide applications of titanium dioxide nanoparticles (TNPs) in day-to-day life in form of cosmetics, paints, sterilisation and so on, there is growing concern regarding the deleterious effects of TNPs on central nervous system and mitochondria appear to be important cellular organelles targeted to the pro-oxidative effects of NPs and an important source that contribute significantly for the production of reactive oxygen species after some toxicity or an injury. The aim of our study was to elucidate the effect of TNPs in anatase form with different concentrations (5-50 µg/ml) following with various oxidative stress markers in isolated brain mitochondria as an in vitro model. Oxidative stress was determined by measuring the different oxidative stress markers like lipid peroxidation as well as the protein carbonyl content which was found to be significantly increased. Reduced glutathione content and major glutathione metabolizing enzymes were also modulated signifying the role of glutathione redox cycle in the pathophysiology of TNPs. The study also includes the mitochondrial enzymes (Complex 1, Complex II, complex IV, Complex V ) and the enzymes showed toxicity in a relatively short time due to the effect of TNPs. The study provide a range of concentration that were toxic to the neuronal cells and data pointing to a general toxicity in brain mitochondria by TNPs, therefore, it is in need to consider the proper utilization of NPs in the environment.

Keywords: mitochondria, nanoparticles, brain, in vitro

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5184 L2 Reading in Distance Education: Analysis of Students' Reading Attitude and Interests

Authors: Ma. Junithesmer, D. Rosales

Abstract:

The study is a baseline description of students’ attitude and interests about L2 reading in a state university in the Philippines that uses distance education as a delivery mode. Most research conducted on this area dealt with the analysis of reading in a traditional school set-up. For this reason, this research was written to discover if there are implications as regards students’ preferences, interests and attitude reveal about L2 reading in a non-traditional set-up. To form the corpus of this study, it included the literature and studies about reading, preferred technological devices, titles of books and authors, reading medium traditional/ print and electronic books that juxtapose with students’ interest and feelings when reading at home and in school; and their views about their strengths and weaknesses as readers.

Keywords: distance education, L2 reading, reading, reading attitude

Procedia PDF Downloads 334
5183 Optimized Electron Diffraction Detection and Data Acquisition in Diffraction Tomography: A Complete Solution by Gatan

Authors: Saleh Gorji, Sahil Gulati, Ana Pakzad

Abstract:

Continuous electron diffraction tomography, also known as microcrystal electron diffraction (MicroED) or three-dimensional electron diffraction (3DED), is a powerful technique, which in combination with cryo-electron microscopy (cryo-ED), can provide atomic-scale 3D information about the crystal structure and composition of different classes of crystalline materials such as proteins, peptides, and small molecules. Unlike the well-established X-ray crystallography method, 3DED does not require large single crystals and can collect accurate electron diffraction data from crystals as small as 50 – 100 nm. This is a critical advantage as growing larger crystals, as required by X-ray crystallography methods, is often very difficult, time-consuming, and expensive. In most cases, specimens studied via 3DED method are electron beam sensitive, which means there is a limitation on the maximum amount of electron dose one can use to collect the required data for a high-resolution structure determination. Therefore, collecting data using a conventional scintillator-based fiber coupled camera brings additional challenges. This is because of the inherent noise introduced during the electron-to-photon conversion in the scintillator and transfer of light via the fibers to the sensor, which results in a poor signal-to-noise ratio and requires a relatively higher and commonly specimen-damaging electron dose rates, especially for protein crystals. As in other cryo-EM techniques, damage to the specimen can be mitigated if a direct detection camera is used which provides a high signal-to-noise ratio at low electron doses. In this work, we have used two classes of such detectors from Gatan, namely the K3® camera (a monolithic active pixel sensor) and Stela™ (that utilizes DECTRIS hybrid-pixel technology), to address this problem. The K3 is an electron counting detector optimized for low-dose applications (like structural biology cryo-EM), and Stela is also a counting electron detector but optimized for diffraction applications with high speed and high dynamic range. Lastly, data collection workflows, including crystal screening, microscope optics setup (for imaging and diffraction), stage height adjustment at each crystal position, and tomogram acquisition, can be one of the other challenges of the 3DED technique. Traditionally this has been all done manually or in a partly automated fashion using open-source software and scripting, requiring long hours on the microscope (extra cost) and extensive user interaction with the system. We have recently introduced Latitude® D in DigitalMicrograph® software, which is compatible with all pre- and post-energy-filter Gatan cameras and enables 3DED data acquisition in an automated and optimized fashion. Higher quality 3DED data enables structure determination with higher confidence, while automated workflows allow these to be completed considerably faster than before. Using multiple examples, this work will demonstrate how to direct detection electron counting cameras enhance 3DED results (3 to better than 1 Angstrom) for protein and small molecule structure determination. We will also show how Latitude D software facilitates collecting such data in an integrated and fully automated user interface.

Keywords: continuous electron diffraction tomography, direct detection, diffraction, Latitude D, Digitalmicrograph, proteins, small molecules

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5182 An Efficient and Low Cost Protocol for Rapid and Mass in vitro Propagation of Hyssopus officinalis L.

Authors: Ira V. Stancheva, Ely G. Zayova, Maria P. Geneva, Marieta G. Hristozkova, Lyudmila I. Dimitrova, Maria I. Petrova

Abstract:

The study describes a highly efficient and low-cost protocol for rapid and mass in vitro propagation of medicinal and aromatic plant species (Hyssopus officinalis L., Lamiaceae). Hyssop is an important aromatic herb used for its medicinal values because of its antioxidant, anti-inflammatory and antimicrobial properties. The protocol for large-scale multiplication of this aromatic plant was developed using young stem tips explants. The explants were sterilized with 0.04% mercuric chloride (HgCl₂) solution for 20 minutes and washing three times with sterile distilled water in 15 minutes. The cultural media was full and half strength Murashige and Skoog medium containing indole-3-butyric acid. Full and ½ Murashige and Skoog media without auxin were used as controls. For each variant 20 glass tubes with two plants were used. In each tube two tip and nodal explants were inoculated. Maximum shoot and root number were obtained on ½ Murashige and Skoog medium supplemented with 0.1 mg L-1 indole-3-butyric acid at the same time after four weeks of culture. The number of shoots per explant and shoot height were considered. The data on rooting percentage, the number of roots per plant and root length were collected after the same cultural period. The highest percentage of survival 85% for this medicinal plant was recorded in mixture of soil, sand and perlite (2:1:1 v/v/v). This mixture was most suitable for acclimatization of all propagated plants. Ex vitro acclimatization was carried out at 24±1 °C and 70% relative humidity under 16 h illuminations (50 μmol m⁻²s⁻¹). After adaptation period, the all plants were transferred to the field. The plants flowered within three months after transplantation. Phenotypic variations in the acclimatized plants were not observed. An average of 90% of the acclimatized plants survived after transferring into the field. All the in vitro propagated plants displayed normal development under the field conditions. Developed in vitro techniques could provide a promising alternative tool for large-scale propagation that increases the number of homologous plants for field cultivation. Acknowledgments: This study was conducted with financial support from National Science Fund at the Bulgarian Ministry of Education and Science, Project DN06/7 17.12.16.

Keywords: Hyssopus officinalis L., in vitro culture, micro propagation, acclimatization

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5181 Analysis of Metamaterial Permeability on the Performance of Loosely Coupled Coils

Authors: Icaro V. Soares, Guilherme L. F. Brandao, Ursula D. C. Resende, Glaucio L. Siqueira

Abstract:

Electrical energy can be wirelessly transmitted through resonant coupled coils that operate in the near-field region. Once in this region, the field has evanescent character, the efficiency of Resonant Wireless Power Transfer (RWPT) systems decreases proportionally with the inverse cube of distance between the transmitter and receiver coils. The commercially available RWPT systems are restricted to short and mid-range applications in which the distance between coils is lesser or equal to the coil size. An alternative to overcome this limitation is applying metamaterial structures to enhance the coupling between coils, thus reducing the field decay along the distance between them. Metamaterials can be conceived as composite materials with periodic or non-periodic structure whose unconventional electromagnetic behaviour is due to its unit cell disposition and chemical composition. This new kind of material has been used in frequency selective surfaces, invisibility cloaks, leaky-wave antennas, among other applications. However, for RWPT it is mainly applied as superlenses which are lenses that can overcome the optical limitation and are made of left-handed media, that is, a medium with negative magnetic permeability and electric permittivity. As RWPT systems usually operate at wavelengths of hundreds of meters, the metamaterial unit cell size is much smaller than the wavelength. In this case, electric and magnetic field are decoupled, therefore the double negative condition for superlenses are not required and the negative magnetic permeability is enough to produce an artificial magnetic medium. In this work, the influence of the magnetic permeability of a metamaterial slab inserted between two loosely coupled coils is studied in order to find the condition that leads to the maximum transmission efficiency. The metamaterial used is formed by a subwavelength unit cell that consist of a capacitor-loaded split ring with an inner spiral that is designed and optimized using the software Computer Simulation Technology. The unit cell permeability is experimentally characterized by the ratio of the transmission parameters between coils measured with and without the presence of the metamaterial slab. Early measurements results show that the transmission coefficient at the resonant frequency after the inclusion of the metamaterial is about three times higher than with just the two coils, which confirms the enhancement that this structure brings to RWPT systems.

Keywords: electromagnetic lens, loosely coupled coils, magnetic permeability, metamaterials, resonant wireless power transfer, subwavelength unit cells

Procedia PDF Downloads 141