Search results for: space resolved kinetic measurements

Authors: C. Benhamideche

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Fluoroaluminate glasses have been reported as the earliest heavy metal fluoride glasses. By comparison with flurozirconate glasses, they offer a set of similar optical features, but also some differences in their elastic and chemical properties. In practice they have been less developed because their stability against devitrification is smaller than that of the most stable fluoroziconates. The purpose of this study was to investigate glass formation in systems AlF3-YF3-PbF2-MgF2-MF2 (M= Li, Na, K). Synthesis was implemented at room atmosphere using the ammonium fluoride processing. After fining, the liquid was into a preheated brass mold, then annealed below the glass transition temperature for several hours. The samples were polished for optical measurements. Glass formation has been investigated in a systematic way, using pseudo ternary systems in order to allow parameters to vary at the same time. We have chosen the most stable glass compositions for the determination of the physical properties. These properties including characteristic temperatures, density and proprieties elastic. Glass stability increases in multicomponent glasses. Bulk samples have been prepared for physical characterization. These glasses have a potential interest for passive optical fibers because they are less sensitive to water attack than ZBLAN glass, mechanically stronger. It is expected they could have a larger damage threshold for laser power transmission.

Keywords: fluoride glass, aluminium fluoride, thermal properties, density, proprieties elastic

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Authors: Nasiruddin Khan, Saud Iqbal

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Arabian Gulf region has undergone enormous development due to oil boom resulting in overwhelming changes in the lifestyle of the population over the past few decades. This study focused on food consumption patterns of Omani university students. Information, on anthropometric measurements, dietary intakes (measured by a food frequency questionnaire) of students was recorded. Anthropometric data revealed 62.5% of the subjects to be of normal weight and approximately 25% being overweight. Female students appeared to be more weight conscious than males. Dietary intakes in terms of servings (Mean ± S.D) per day among normal weight (BMI 18.5 – 24.9) males vs. females were approximately; cereals (7.5 ± 5.9 vs. 4.9 ± 2.9 servings), meat and alternatives (1.9 ± 0.9 vs. 1.5 ± 0.9 servings), dairy foods (0.9 ± 0.8 vs. 1.1 ± 0.9 servings) per day, respectively. Overall 55.3% of both males (average 1.9 servings) as well as females (average 1.7 servings) had severely inadequate intakes of vegetables on a daily basis as per the food guide pyramid recommendations. Only the fruit group intakes were adequate in about 70% of the population. Adequate intakes of dairy and meat and alternatives group were found in only 22% and 32% of the subjects, respectively. These results indicate a significant influence of a modern lifestyle on dietary habits and food selection of the target population.

Keywords: dietary pattern, food guide pyramid, lifestyle, Oman

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Authors: A. L. R. Rangel, J. A. M. Chaves, A. P. R. Alves Claro

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Surface modification of titanium and its alloys using TiO2 nanotube growth has been widely studied for biomedical field due to excellent interaction between implant and biological environment. The success of this treatment is directly related to anatase phase formation (TiO2 phase) which affects the cells growth. The aim of this study was to evaluate the phases formed in the nanotubes growth on the Ti-15Mo surface. Nanotubes were grown by electrochemical anodization of the alloy in ammonium fluoride based glycerol electrolyte for 24 hours at 20V. Then, the samples were annealed at 200°,400°, 450°, 500°, 600°, and 800° C for 1 hour. Contact angles measurements, scanning electron microscopy images and X rays diffraction analysis (XRD) were carried out for all samples. Raman Spectroscopy was used to evaluate TiO2 phases transformation in nanotubes samples as well. The results of XRD showed anatase formation for lower temperatures, while at 800 ° C the rutile phase was observed all over the surface. Raman spectra indicate that this phase transition occurs between 500 and 600 °C. The different phases formed have influenced the nanotubes morphologies, since higher annealing temperatures induced agglutination of the TiO2 layer, disrupting the tubular structure. On the other hand, the nanotubes drastically reduced the contact angle, regardless the annealing temperature.

Keywords: nanotubes, TiO2, titanium alloys, Ti-15Mo

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Authors: Ramy Kamel Fekrey Gadelrab

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Textile sensors have gained a lot of interest in recent years as it is instrumental in monitoring physiological and environmental changes, for a better diagnosis that can be useful in various fields like medical textiles, sports textiles, protective textiles, agro textiles, and geo-textiles. Moreover, with the development of flexible textile-based wearable sensors, the functionality of smart clothing is augmented for a more improved user experience when it comes to technical textiles. In this context, conductive textiles using new composites and nanomaterials are being developed while considering its compatibility with the textile manufacturing processes. This review aims to provide a comprehensive and detailed overview of the contemporary advancements in textile-based wearable physical sensors, used in the field of medical, security, surveillance, and protection, from a global perspective. The methodology used is through analysing various examples of integration of wearable textile-based sensors with clothing for daily use, keeping in mind the technological advances in the same. By comparing various case studies, it come across various challenges textile sensors, in terms of stability, the comfort of movement, and reliable sensing components to enable accurate measurements, in spite of progress in the engineering of the wearable. Addressing such concerns is critical for the future success of wearable sensors.

Keywords: nanoparticles, enzymes, immobilization, textilesconductive yarn, e-textiles, smart textiles, thermal analysisflexible textile-based wearable sensors, contemporary advancements, conductive textiles, body conformal design

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Authors: Fabian Velasquez, John Espitia, Henry Hernadez, Sebastian Escobar, Jader Rodriguez

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Non-centrifuged cane sugar (NCS) is a concentrated product obtained through the evaporation of water contain from sugarcane juice inopen heat exchangers (OE). The heat supplied to the evaporation stages is obtained from the cane bagasse through the thermochemical process of combustion, where the thermal energy released is transferred to OE by the flue gas. Therefore, the optimization of energy usage becomes essential for the proper design of the production process. For optimize the energy use, it is necessary modeling and simulation of heat transfer between the combustion gases and the juice and to understand the major mechanisms involved in the heat transfer. The main objective of this work was simulated heat transfer phenomena between the flue gas and open heat exchangers using Computational Fluid Dynamics model (CFD). The simulation results were compared to field measured data. Numerical results about temperature profile along the flue gas pipeline at the measurement points are in good accordance with field measurements. Thus, this study could be of special interest in design NCS production process and the optimization of the use of energy.

Keywords: mathematical modeling, design variables, computational fluid dynamics, overall thermal efficiency

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Authors: O. Arbouche, Y. Benallou, K. Amara

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We report a first-principles study of structural, electronic and magnetic properties of ternary plumbides (rare earth-transition metal-Plumb) Dy2Ni2Pb crystallizes with the orthorhombic structure of the Mn2AlB2 type (space group Cmmm), were studied by means of the full-relativistic version of the full-potential augmented plane wave plus local orbital method within the frame work of spin-polarized density functional theory (SP-DFT). The electronic exchange-correlation energy is described by generalized gradient approximation (GGA). We have calculated the lattice parameters, bulk modulii and the first pressure derivatives of the bulk modulii, total densities of states and magnetic properties. The calculated total magnetic moment is found to be equal to 9.52 μB.

Keywords: spin-polarized, magnetic properties, Dy2Ni2Pb, Density functional theory

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Authors: Margarita Zavala, Julio Rolón, Gabriel Chavira, José González, Jorge Orozco, Roberto Pichardo

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Adolescence is a neuralgic stage in the formation of every human being, generally at this stage is when the middle school level is studied. In 2006 in Mexico incorporated “mentoring" space to assist students in their integration and participation in life. In public middle schools, is sometimes difficult to be aware of situations that affect students because of the number of them and traditional records management. Whit this they lose the opportunity to provide timely support as a preventive way. In order to provide this support, it is required to know the students by detecting the relevant information that has greater impact on their learning process. This research is looking to check if it is possible to identify student’s relevant information to detect when it is at risk, and then to propose a model to manage in a proper way such information.

Keywords: adolescence, mentoring, middle school students, mentoring system support

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Authors: Ahmed Alutaibi, Ganti Sudhakar

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Providing better Quality-of-Service (QoS) to end users has been a challenging problem for researchers and service providers. Building applications relying on best effort network protocols hindered the adoption of guaranteed service parameters and, ultimately, Quality of Service. The introduction of Software Defined Networking (SDN) opened the door for a new paradigm shift towards a more controlled programmable configurable behavior. Openflow has been and still is the main implementation of the SDN vision. To facilitate better QoS for applications, the network must calculate and measure certain parameters. One of those parameters is the delay between the two ends of the connection. Using the power of SDN and the knowledge of application and network behavior, SDN networks can adjust to different conditions and specifications. In this paper, we use the capabilities of SDN to implement multiple algorithms to measure delay end-to-end not only inside the SDN network. The results of applying the algorithms on an emulated environment show that we can get measurements close to the emulated delay. The results also show that depending on the algorithm, load on the network and controller can differ. In addition, the transport layer handshake algorithm performs best among the tested algorithms. Out of the results and implementation, we show the limitations of Openflow and develop suggestions to solve them.

Keywords: software defined networking, quality of service, delay measurement, openflow, mininet

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Authors: J. J. Vargas, N. Prieto, L. A. Toro

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Control charts are commonly used to monitor processes involving either variable or attribute of quality characteristics and determining the control limits as a critical task for quality engineers to improve the processes. Nonetheless, in some applications it is necessary to include an estimation of efficiency. In this paper, the ability to define the efficiency of an industrial process was added to a control chart by means of incorporating a data envelopment analysis (DEA) approach. In depth, a Bayesian estimation was performed to calculate the posterior probability distribution of parameters as means and variance and covariance matrix. This technique allows to analyse the data set without the need of using the hypothetical large sample implied in the problem and to be treated as an approximation to the finite sample distribution. A rejection simulation method was carried out to generate random variables from the parameter functions. Each resulting vector was used by stochastic DEA model during several cycles for establishing the distribution of each efficiency measures for each DMU (decision making units). A control limit was calculated with model obtained and if a condition of a low level efficiency of DMU is presented, system efficiency is out of control. In the efficiency calculated a global optimum was reached, which ensures model reliability.

Keywords: data envelopment analysis, DEA, Multivariate control chart, rejection simulation method

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Authors: Idris Adamu Alhaji, Wan Fauziahbt Wan Yusoff

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This study was conducted to identify the relationship between Corporate Governance attributes and Firm Performance, various studies, had been carried out mostly in developed countries, in order to identify the relationship between corporate governance attributes and firm performance. Since, the value creation of corporate governance can be measured through the firm performance, corporate governance act as a mechanism to align management's goals with the stakeholders especially to increase firm performance. Despite extensive study of corporate governance there is still an inconsistence relationship between corporate governance attributes and firm performance. Therefore, the aim of this paper is to identify the relationship between corporate governance attributes and firm performance. Five corporate governance element were used as independent variables which include: Independent director, board size, audit committee, leadership structure and board meeting. Meanwhile, the dependent variables are two firm performance measurements; return on equity (ROE) and earning per share (EPS). This study uses quantitative approaches whereby data were gathered from secondary source data were collected from Annual Reports of the companies, online journals etc. This study revealed that, there is a significant relationship between corporate governance attributes and firm performance. Therefore, the results show that good corporate governance practice influence firm performance. Finally, it's hoped that this study provides current corporate governance scenario in Malaysia that can be used to enhance the development of corporate governance of the country.

Keywords: corporate governance, return on equity, earning per share, financial performance

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Authors: Meksem Nabila, Bordjiba Ouahiba, Meraghni Messaouda, Meksem Amara Leila, Djebar Mohhamed Reda

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The problems of protection of the cultures are being more and more important that they interest great number of farmers and scientists because of the excessive use of the organic phytosanitary products of synthesis that causes fatal damages on the environment. To reduce the inconveniences produced by these pesticides, the use of "biopesticides" originated from plants could be an alternative. The aim of this work is the valuation of a botanical species: Eucalyptus camaldulensis from Northeastern Algeria which extracts are supposed to have an antimicrobial activity, similar to pesticides. The extraction of secondary metabolites from the leaves of E. camaldulensis was realized using methanol and water, and measurements of total polyphenols were made by spectrometric method. Determination of the antimicrobial activity of the extracts at issue was realized in vitro on phyto-pathogenic fungal and bacterial stumps. Tests of comparison were included in the essays by using the chemical pesticidal products of synthesis. The obtained results show that the plant contains polyphenols with an efficiency mattering of the order of 22 %. These polyphenols have a strong fungicidal and bactericidal pesticidal activity against various microbial stumps and the values of the zones of inhibition are more important compared with that obtained in the presence of the chemicals of synthesis (fungicide).

Keywords: eucalyptus camaldulensis, biopesticide, polyphenols, antimicrobial activity

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Authors: Ratna Tantra

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From a risk assessment point of view, solubility is a property that has been identified as being important. If nanomaterial is completely soluble, then its disposal can be treated much in the same way as ‘ordinary’ chemicals, which subsequently will simplify testing and characterization regimes. The measurement of solubility has been highlighted as important in a pan-European project, Framework Programme (FP) 7 NANoREG. Some of the project outputs surrounding this topic will be presented here, in which there are two parts. First, a review on existing methods capable of measuring nanomaterial solubility will be discussed. Second, a case study will be presented based on using colorimetry methods to quantify dissolve zinc from ZnO nanomaterial upon exposure to digestive juices. The main findings are as follows: a) there is no universal method for nanomaterial solubility testing. The method chosen will be dependent on sample type and nano-specific application/scenario. b) The colorimetry results show a positive correlation between particle concentration and amount of [Zn2+] released; this was expected c) results indicate complete dissolution of the ZnO nanomaterial, as a result of the digestion protocol but only a fraction existing as free ions. Finally, what differentiates the F7 NANoREG project over other projects is the need for participating research laboratories to follow a set of defined protocols, necessary to establish quality control and assurance. The methods and results associated with mandatory testing that carried out by all partners in NANoREG will be discussed.

Keywords: nanomaterials, nanotoxicology, solubility, zinc oxide

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Authors: Tomilola J. Ajayi, Moses Ollengo, Lukas le Roux, Michael N. Pillay, Richard J. Staples, Shannon M. Biros Werner E. van Zyl

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The formation, characterization, and dye-sensitized solar cell application of nickel(II), zinc(II) and cadmium(II) ferrocenyl dithiophosphonate complexes were investigated. The multidentate monoanionic ligand [S₂PFc(OH)]¯ (L1) was synthesized from the reaction between ferrocenyl Lawesson’s reagent, [FcP(=S)μ-S]₂ (FcLR), (Fc = ferrocenyl) and water. Ligand L1 could potentially coordinate to metal centers through the S, S’ and O donor atoms. The reaction between metal salt precursors and L1 produced a Ni(II) complex of the type [Ni{S₂P(Fc)(OH)}₂] (1) (molar ratio 1:2), a tetranickel (II) complex of the type [Ni₂{S₂OP(Fc)}₂]₂ (2) (molar ratio (1:1), as well as a Zn(II) complex [Zn{S₂P(Fc)(OH)}₂]₂ (3), and a Cd(II) complex [Cd{S₂P(Fc)(OH)}₂]₂ (4). Complexes 1-4 were characterized by 1H and 31P NMR and FT-IR, and complexes 1 and 2 were additionally analysed by X-Ray crystallography. After co-sensitization, the DSSCs were characterized using UV-Vis, cyclic voltammetry, electrochemical impedance spectroscopy, and photovoltaic measurements (I-V curves). Overall finding shows that co-sensitization of our compounds with ruthenium dye N719 resulted in a better overall solar conversion efficiency than only pure N719 dye under the same experimental conditions. In conclusion, we report the first examples of dye-sensitized solar cells (DSSCs) co-sensitized with ferrocenyl dithiophosphonate complexes.

Keywords: dithiophosphonate, dye sensitized solar cell, co-sensitization, solar efficiency

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Authors: M. Y. Bakeir

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Rough set theory is a recent approach for reasoning about data. It has achieved a large amount of applications in various real-life fields. The main idea of rough sets corresponds to the lower and upper set approximations. These two approximations are exactly the interior and the closure of the set with respect to a certain topology on a collection U of imprecise data acquired from any real-life field. The base of the topology is formed by equivalence classes of an equivalence relation E defined on U using the available information about data. The theory of generalized topology was studied by Cs´asz´ar. It is well known that generalized topology in the sense of Cs´asz´ar is a generalization of the topology on a set. On the other hand, many important collections of sets related with the topology on a set form a generalized topology. The notion of Nano topology was introduced by Lellis Thivagar, which was defined in terms of approximations and boundary region of a subset of an universe using an equivalence relation on it. The purpose of this paper is to introduce a new generalized topology in terms of rough set called nano generalized topology

Keywords: rough sets, topological space, generalized topology, nano topology

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Authors: Jayanta K. Behera, Ashwini K. Sinha

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The study has pointed out the relationship of energetic particle precipitation (EPP) during high speed solar wind streams (HSS) to the ionization characteristics and subsequent NOx production in the polar atmosphere. Over the last few decades, it has been shown that production of NOx in the mesosphere region during the precipitation of charged particles (with energy range >30 KeV to 1 MeV) is directly related to the ozone loss in the polar middle atmosphere, extending from mesosphere to upper stratosphere. This study has dealt with the analysis of the interplanetary parameters such as interplanetary magnetic field (IMF), solar wind velocity (Vs), charged particle density (Ns), convection field enhancement (Ec) during such HSS events and their link to the rate of production of NOx in the mesosphere. Moreover, the analysis will be used to validate or, to modify the current ion-chemistry models which describe the ionization rate and NOx production in the polar atmosphere due to EPP.

Keywords: energetic particle precipitation (EPP), NOx, ozone depletion, polar vortex

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Authors: Achraf Al Faraj, Asma Sultana Shaik, Baraa Al Sayed

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Specific and effective targeting of drug delivery systems (DDS) to cancerous sites remains a major challenge for a better diagnostic and therapy. Recently, SWCNTs with their unique physicochemical properties and the ability to cross the cell membrane show promising in the biomedical field. The purpose of this study was first to develop a biocompatible iron oxide tagged SWCNTs as diagnostic nanoprobes to allow their noninvasive detection using MRI and their preferential targeting in a breast cancer murine model by placing an optimized flexible magnet over the tumor site. Magnetic targeting was associated to specific antibody-conjugated SWCNTs active targeting. The therapeutic efficacy of doxorubicin-conjugated SWCNTs was assessed, and the superiority of diffusion-weighted (DW-) MRI as sensitive imaging biomarker was investigated. Short Polyvinylpyrrolidone (PVP) stabilized water soluble SWCNTs were first developed, tagged with iron oxide nanoparticles and conjugated with Endoglin/CD105 monoclonal antibodies. They were then conjugated with doxorubicin drugs. SWCNTs conjugates were extensively characterized using TEM, UV-Vis spectrophotometer, dynamic light scattering (DLS) zeta potential analysis and electron spin resonance (ESR) spectroscopy. Their MR relaxivities (i.e. r1 and r2*) were measured at 4.7T and their iron content and metal impurities quantified using ICP-MS. SWCNTs biocompatibility and drug efficacy were then evaluated both in vitro and in vivo using a set of immunological assays. Luciferase enhanced bioluminescence 4T1 mouse mammary tumor cells (4T1-Luc2) were injected into the right inguinal mammary fat pad of Balb/c mice. Tumor bearing mice received either free doxorubicin (DOX) drug or SWCNTs with or without either DOX or iron oxide nanoparticles. A multi-pole 10x10mm high-energy flexible magnet was maintained over the tumor site during 2 hours post-injections and their properties and polarity were optimized to allow enhanced magnetic targeting of SWCNTs toward the primary tumor site. Tumor volume was quantified during the follow-up investigation study using a fast spin echo MRI sequence. In order to detect the homing of SWCNTs to the main tumor site, susceptibility-weighted multi-gradient echo (MGE) sequence was used to generate T2* maps. Apparent diffusion coefficient (ADC) measurements were also performed as a sensitive imaging biomarker providing early and better assessment of disease treatment. At several times post-SWCNT injection, histological analysis were performed on tumor extracts and iron-loaded SWCNT were quantified using ICP-MS in tumor sites, liver, spleen, kidneys, and lung. The optimized multi-poles magnet revealed an enhanced targeting of magnetic SWCNTs to the primary tumor site, which was found to be much higher than the active targeting achieved using antibody-conjugated SWCNTs. Iron-loading allowed their sensitive noninvasive tracking after intravenous administration using MRI. The active targeting of doxorubicin through magnetic antibody-conjugated SWCNTs nanoprobes was found to considerably decrease the primary tumor site and may have inhibited the development of metastasis in the tumor-bearing mice lung. ADC measurements in DW-MRI were found to significantly increase in a time-dependent manner after the injection of DOX-conjugated SWCNTs complexes.

Keywords: single-walled carbon nanotubes, nanomedicine, magnetic resonance imaging, cancer diagnosis and therapy

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Authors: F. Amirarfaei, K. Khorasani

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In this paper, reconfigurable consensus achievement of a team of agents with marginally stable linear dynamics and single input channel has been considered. The control algorithm is based on a first order linear protocol. After occurrence of a LOE fault in one of the actuators, using the imperfect information of the effectiveness of the actuators from fault detection and identification module, the control gain is redesigned in a way to still reach consensus. The idea is based on the modeling of change in effectiveness as change of Laplacian matrix. Then as special cases of this class of systems, a team of single integrators as well as double integrators are considered and their behavior subject to a LOE fault is considered. The well-known relative measurements consensus protocol is applied to a leaderless team of single integrator as well as double integrator systems, and Gersgorin disk theorem is employed to determine whether fault occurrence has an effect on system stability and team consensus achievement or not. The analyses show that loss of effectiveness fault in actuator(s) of integrator systems affects neither system stability nor consensus achievement.

Keywords: multi-agent system, actuator fault, stability analysis, consensus achievement

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Authors: Mohamed Elmeshad

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During the mid-1990's Egypt had become obliged to implement the Economic Reform and Structural Adjustment Program that included broad economic liberalization, expansion of the private sector and a contraction the size of government spending. This coincided as well with attempts to appear more democratic and open to liberalizing public space and discourse. At the same time, economic pressures and the proliferation of social media access and activism had led to increased pressure to open a mediascape and remove it from the clutches of the government, which had monopolized print and broadcast mass media for over 4 decades by that point. However, the mechanisms that governed the privatization of mass media allowed for sustained government control, even through the prism of ostensibly privately owned newspapers and television stations. These mechanisms involve barriers to entry from a financial and security perspective, as well as operational capacities of distribution and access to means of production. The power dynamics between mass media establishments and the state were moulded during this period in a novel way. Power dynamics within media establishments had also formed under such circumstances. The changes in the country's political economy itself somehow mirrored these developments. This paper will examine these dynamics and shed light on the political economy of Egypt's newly privatized mass media in the early 2000's especially. Methodology: This study will rely on semi-structured interviews from individuals involved with these changes from the perspective of the media organizations. It also will map out the process of media privatization by looking at the administrative, operative and legislative institutions and contexts in order to attempt to draw conclusions on methods of control and the role of the state during the process of privatization. Finally, a brief discourse analysis will be necessary in order to aptly convey how these factors ultimately reflected on media output. Findings and conclusion: The development of Egyptian private, “independent” mirrored the trajectory of transitions in the country’s political economy. Liberalization of the economy meant that a growing class of business owners would explore opportunities that such new markets would offer. However the regime’s attempts to control access to certain forms of capital, especially in sectors such as the media affected the structure of print and broadcast media, as well as the institutions that would govern them. Like the process of liberalisation, much of the regime’s manoeuvring with regards to privatization of media had been haphazardly used to indirectly expand the regime and its ruling party’s ability to retain influence, while creating a believable façade of openness. In this paper, we will attempt to uncover these mechanisms and analyse our findings in ways that explain how the manifestations prevalent in the context of a privatizing media space in a transitional Egypt provide evidence of both the intentions of this transition, and the ways in which it was being held back.

Keywords: business, mass media, political economy, power, privatisation

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Authors: Abdi Ismail, Zain Amarta, Riza Rifaldy Argaputra

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The Helical Turbine has the highest efficiency in comparison with the other hydrokinetic turbines. However, the potential of the Helical Turbine efficiency can be further improved so that the kinetic energy of a water current can be converted into mechanical energy as much as possible. This paper explains the effects by adding a Movable Airfoil Arm (MAA) and ducting on a Helical Turbine. The first research conducted an analysis of the efficiency comparison between a Plate Arm Helical Turbine (PAHT) versus a Movable Arm Helical Turbine Airfoil (MAAHT) at various water current velocities. The first step is manufacturing a PAHT and MAAHT. The PAHT and MAAHT has these specifications (as a fixed variable): 80 cm in diameter, a height of 88 cm, 3 blades, NACA 0018 blade profile, a 10 cm blade chord and a 60o inclination angle. The MAAHT uses a NACA 0012 airfoil arm that can move downward 20o, the PAHT uses a 5 mm plate arm. At the current velocity of 0.8, 0.85 and 0.9 m/s, the PAHT respectively generates a mechanical power of 92, 117 and 91 watts (a consecutive efficiency of 16%, 17% and 11%). At the same current velocity variation, the MAAHT respectively generates 74, 60 and 43 watts (a consecutive efficiency of 13%, 9% and 5%). Therefore, PAHT has a better performance than the MAAHT. Using analysis from CFD (Computational Fluid Dynamics), the drag force of MAA is greater than the one generated by the plate arm. By using CFD analysis, the drag force that occurs on the MAA is more dominant than the lift force, therefore the MAA can be called a drag device, whereas the lift force that occurs on the helical blade is more dominant than the drag force, therefore it can be called a lift device. Thus, the lift device cannot be combined with the drag device, because the drag device will become a hindrance to the lift device rotation. The second research conducted an analysis of the efficiency comparison between a Ducted Helical Turbine (DHT) versus a Helical Turbine (HT) through experimental studies. The first step is manufacturing the DHT and HT. The Helical turbine specifications (as a fixed variable) are: 40 cm in diameter, a height of 88 cm, 3 blades, NACA 0018 blade profile, 10 cm blade chord and a 60o inclination angle. At the current speed of 0.7, 0.8, 0.9 and 1.1 m/s, the HT respectively generates a mechanical power of 72, 85, 93 and 98 watts (a consecutive efficiency of 38%, 30%, 23% and 13%). At the same current speed variation, the DHT generates a mechanical power of 82, 98, 110 and 134 watts (a consecutive efficiency of 43%, 34%, 27% and 18%), respectively. The usage of ducting causes the water current speed around the turbine to increase.

Keywords: hydrokinetic turbine, helical turbine, movable airfoil arm, ducting

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Authors: Marine Segui, Ruxandra Mihaela Botez

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OpenVSP is an aerodynamic solver developed by National Aeronautics and Space Administration (NASA) that allows building a reliable model of an aircraft. This software performs an aerodynamic simulation according to the angle of attack of the aircraft makes between the incoming airstream, and its speed. A reliable aerodynamic model of the Cessna Citation X was designed but it required a lot of computation time. As a consequence, a prediction method was established that allowed predicting lift and drag coefficients for all Mach numbers and for all angles of attack, exclusively for stall conditions, from a computation of three angles of attack and only one Mach number. Aerodynamic coefficients given by the prediction method for a Cessna Citation X model were finally compared with aerodynamics coefficients obtained using a complete OpenVSP study.

Keywords: aerodynamic, coefficient, cruise, improving, longitudinal, openVSP, solver, time

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Authors: Ming-Yen Chang, Sheng-Hung Ke

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This research focuses on the development of a speed bump identification system for real-time control of adjustable shock absorbers in vehicular suspension systems. The study initially involved the collection of images of various speed bumps, and rubber speed bump profiles found on roadways. These images were utilized for training and recognition purposes through the deep learning object detection algorithm YOLOv5. Subsequently, the trained speed bump identification program was integrated with an in-vehicle camera system for live image capture during driving. These images were instantly transmitted to a computer for processing. Using the principles of monocular vision ranging, the distance between the vehicle and an approaching speed bump was determined. The appropriate control distance was established through both practical vehicle measurements and theoretical calculations. Collaboratively, with the electronically adjustable shock absorbers equipped in the vehicle, a shock absorber control system was devised to dynamically adapt the damping force just prior to encountering a speed bump. This system effectively mitigates passenger discomfort and enhances ride quality.

Keywords: adjustable shock absorbers, image recognition, monocular vision ranging, ride

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Authors: Rafik Baouche, Rabah Chaouchi

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This work reports the first comprehensive stress field interpretation from the eleven recently drilled wells in the Berkaoui Basin, Algerian Sahara. A cumulative length of 7000+m acoustic image logs from 06 vertical wells were investigated, and a mean NW-SE (128°-145° N) maximum horizontal stress (SHMax) orientation is inferred from the B-D quality wellbore breakouts. The study integrates log-based approach with the downhole measurements to infer pore pressure, in-situ stress magnitudes. Vertical stress (Sv), interpreted from the bulk-density profiles, has an average gradient of 22.36 MPa/km. The Ordovician and Cambrian reservoirs have a pore pressure gradient of 13.47-13.77 MPa/km, which is more than the hydrostatic pressure regime. A 17.2-18.3 MPa/km gradient of minimum horizontal stress (Shmin) is inferred from the fracture closure pressure in the reservoirs. Breakout widths constrained the SHMax magnitude in the 23.8-26.5 MPa/km range. Subsurface stress distribution in the central Saharan Algeria indicates that the present-day stress field in the Berkaoui Basin is principally strike-slip faulting (SHMax > Sv > Shmin). Inferences are drawn on the regional stress pattern and drilling and reservoir development.

Keywords: stress, imagery, breakouts, sahara

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Authors: Leonardo Dias Cruz

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The advent of web 2.0 has enabled users to engage in translocal and transtemporal interactions in which meanings can be constantly (re)constructed. The fluidity of such interactions in the time-space spectrum makes it evident that D/discourses are always in movement and that here-and-now discursive practices are always linked to macro Discourses in social structures. Considering these assumptions, this study aims at exploring the social construction of masculinities in light of feminist D/discourses in online interactions. The data used are a series of comments from readers of articles posted in a website for (projected) male audiences. In order to approach the movable and fluid nature of such interactions, I examine the data through the lens of processes of entextualization, social positioning and indexical cues. The analysis explores the interactions as social arenas in which struggles for the control over entextualization processes are clearly noticeable. Moreover, two main stances are perceived: one that legitimates male’s participation in Feminism and one that rejects such participation.

Keywords: entextualization, feminism, masculinities, positionings

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Authors: Rizwan Ahmed Bhutto, Noor ul ain Hira Bhutto, Mingwei Wang, Shahid Iqbal, Jiang Yi

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Curcumin, a natural polyphenolic compound, boasts numerous health benefits; however, its industrial applications are hindered by instabilities and poor solubility. Encapsulating curcumin in Pickering emulsion presents a promising strategy to enhance its bioavailability. Yet, the development of an efficient and straightforward method to fabricate a natural emulsifier for Pickering emulsion poses a significant challenge. Chitosan has garnered attention due to its non-toxicity and excellent emulsifying properties. This study aimed to prepare four distinct types of self-aggregated chitosan particles using a pH-responsive self-assembling approach. The properties of the aggregated particles were adjusted by pH, degree of deacetylation (DDA), and molecular weight (MW), thereby controlling surface charge, size (ranging from nano to micro and floc), and contact angle. Pickering emulsions were then formulated using these various aggregated particles. As MW and pH increased and DDA decreased, the networked structures of the aggregated particles formed, resulting in highly elastic gels that were more resistant to the breakdown of Pickering emulsion at ambient temperature. With elevated temperatures, the kinetic energy of the aggregated particles increased, disrupting hydrogen bonds and potentially transforming the systems from fluids to gels. The Pickering emulsion based on aggregated particles served as a carrier for curcumin encapsulation. It was observed that DDA and MW played crucial roles in regulating drug loading, encapsulation efficiency, and release profile. This research sheds light on selecting suitable chitosan for controlling the release of bioactive compounds in Pickering emulsions, considering factors such as adjustable rheological properties, microstructure, and macrostructure. Furthermore, this study introduces an environmentally friendly and cost-effective synthesis of pH-responsive aggregate particles without the need for high-pressure homogenizers. It underscores the potential of aggregate particles with various MWs and DDAs for encapsulating other bioactive compounds, offering valuable applications in industries including food, flavor/fragrance, cosmetics, and medicine.

Keywords: chitosan, molecular weight, rheological properties, curcumin encapsulation

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Authors: Z. M. Iqbal, M. Abdullah, K. Javed, M. A. Jabbar, A. Haque, M. Saadullah, F. Shahzad

Abstract:

The current study was conducted to set the appropriate concentrate level for Nili-Ravi buffalo heifers. Twenty seven buffalo heifers were randomly divided into three different groups A, B and C having nine animals in each group. All the heifers were given free access to chopped green fodder and fresh water. In addition, heifers of group A, B and C were given concentrate at the rate of 0.5%, 1% and 1.5% of their body weight. The average daily dry matter intake was 2.69, 3.06 and 3.83 kg with average daily gain of 456.09, 398.56 and 515.87 gm in group A, B and C, respectively. The feed conversion ratio of heifers of these groups was 5.89, 7.74 and 7.52, respectively. There was non-significant (P>0.05) difference in the body measurements (height at wither, body length and heart girth), final body condition and scoring and blood serum (glucose, total protein and cholesterol) of heifers of all the three groups. The results of current study shows that there is non-significant (P>0.05) difference in the growth rate of Nili-Ravi heifers at varying levels of concentrate so, it is cost effective to raise 6-8 month calves by offering concentrate at the rate of 0.5% body weight along with free access of green fodder.

Keywords: concentrate level, buffalo heifer, body measurement, green fodder

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Authors: Orsolya Kegyes-Brassai, Zsolt Szilvágyi, Ákos Wolf, Richard P. Ray

Abstract:

Local ground conditions have a substantial influence on the seismic response of structures. Their inclusion in seismic hazard assessment and structural design can be realized at different levels of sophistication. However, response results based on more advanced calculation methods e.g. nonlinear or equivalent linear site analysis tend to show significant discrepancies when compared to simpler approaches. This project's main objective was to compare results from several 1-D response programs to Eurocode 8 design spectra. Data from in-situ site investigations were used for assessing local ground conditions at several locations in Hungary. After discussion of the in-situ measurements and calculation methods used, a comprehensive evaluation of all major contributing factors for site response is given. While the Eurocode spectra should account for local ground conditions based on soil classification, there is a wide variation in peak ground acceleration determined from 1-D analyses versus Eurocode. Results show that current Eurocode 8 design spectra may not be conservative enough to account for local ground conditions typical for Hungary.

Keywords: 1-D site response analysis, multichannel analysis of surface waves (MASW), seismic CPT, seismic hazard assessment

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Authors: Junjie Fu

Abstract:

This paper explores the cultural evolution of the "city-mountain" landscape in ancient Chinese cities, tracing its origins in the regional mountain and town division within the national system. It delves into the cultural archetype of "city-mountain" landscape divine imagery and its spatial characteristics, drawing from the spatial conception of mountain worship and divine order in the model of Kunlun and Penglai. Furthermore, it examines the shift from religious to daily life influences, leading to a poetic aesthetic turn in the "city-mountain" landscape. The paper also discusses the organizational structure of the "city-mountain" poetic landscape and its role as a space for enjoyment. By studying the cultural connotations, evolving relationships, and power mechanisms of the "city-mountain" landscape, this research provides theoretical insights for the construction and development of "city-mountain" landscapes and mountain cities.

Keywords: city-mountain landscape, cultural image, divinity, landscape image, poetry

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Authors: Berger Saintius, Edna Ariste, Djeamsly Salomon

Abstract:

Background: Maternal mortality is a preventable global health problem that affects developed, developing, and underdeveloped countries alike. Globally, maternal mortality rates have declined since 1990, but 830 women die every day from pregnancy and childbirth-related causes that are often preventable. Haiti, with a number of 529 maternal deaths per 100,000 live births, is one of the countries with the highest maternal mortality rate in the Caribbean. This study consists of analyzing maternal death surveillance data in Haiti from 2017-2020. Method : A descriptive study was conducted; data were extracted from the National Epidemiological Surveillance Network of maternal deaths from 2017 to 2020. Sociodemographic variables were analyzed. Excel and Epi Info 7.2 were used for data analysis. Frequency and proportion measurements were calculated. Results: 756 deaths were recorded for the study period: 42 (6%) in 2017, 168 (22%) in 2018, 265 (35%) in 2019, and 281 (37%) in 2020. The North Department recorded the highest number of deaths, 167 (22%). 83(11%) in Les Cayes. 96% of these deaths are people aged between 15 and 49. Conclusion. Maternal mortality is a major health problem in Haiti. Mobilization, participation, and involvement of communities, increase in obstetric care coverage and promotion of Family Planning are among the strategies to fight this problem.

Keywords: epidemiology, maternal death, hospital, Haiti

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Authors: Masaru Sumida

Abstract:

This study explored the feasibility of improving the hydraulic headbox of papermaking machines by studying the flow of wood-pulp suspensions behind a flat plate inserted in parallel and convergent channels. Pulp fiber concentrations of the wake downstream of the plate were investigated by flow visualization and optical measurements. Changes in the time-averaged and fluctuation of the fiber concentration along the flow direction were examined. In addition, the control of the flow characteristics in the two channels was investigated. The behaviors of the pulp fibers and the wake flow were found to be strongly related to the flow states in the upstream passages partitioned by the plate. The distribution of the fiber concentration was complex because of the formation of a thin water layer on the plate and the generation of Karman’s vortices at the trailing edge of the plate. Compared with the flow in the parallel channel, fluctuations in the fiber concentration decreased in the convergent channel. However, at low flow velocities, the convergent channel has a weak effect on equilibrating the time-averaged fiber concentration. This shows that a rectangular trailing edge cannot adequately disperse pulp suspensions; thus, at low flow velocities, a convergent channel is ineffective in ensuring uniform fiber concentration.

Keywords: fiber dispersion, headbox, pulp liquid, wake flow

Procedia PDF Downloads 377

Authors: Mounir Adal, Baalal Azeddine, Afifi Moulay Larbi

Abstract:

Numerical analysis is a branch of mathematics devoted to the development of iterative matrix calculation techniques. We are searching for operations optimization as objective to calculate and solve systems of equations of order n with time and energy saving for computers that are conducted to calculate and analyze big data by solving matrix equations. Furthermore, this scientific discipline is producing results with a margin of error of approximation called rates. Thus, the results obtained from the numerical analysis techniques that are held on computer software such as MATLAB or Simulink offers a preliminary diagnosis of the situation of the environment or space targets. By this we can offer technical procedures needed for engineering or scientific studies exploitable by engineers for water.

Keywords: numerical analysis methods, obstacles solving, engineering, simulation, numerical modeling, iteration, computer, MATLAB, water, underground, velocity

Procedia PDF Downloads 459