Search results for: SnO2 film

Authors: Yasser M. Abd-elrhman, Mohamed A. Gepreel, Kiochi Nakamura, Ahmed Abd El-Moneim, Sengo Kobayashi, Mervat M. Ibrahim

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Titanium alloys are known as highly bio compatible metallic materials due to their high strength, low elastic modulus, and high corrosion resistance in biological media. Besides other important material features, the corrosion parameters and corrosion products are responsible for limiting the biological and chemical bio compatibility of metallic materials that produce undesirable reactions in implant-adjacent and/or more distant tissues. Electrochemical corrosion behaviors of novel beta titanium alloys, Ti-4.7Mo-4.5Fe, Ti-3Mo-0.5Fe, and Ti-2Mo-0.5Fe were characterized in naturally aerated Ringer’s solution at room temperature compared with common used biomedical titanium alloy, Ti-6Al-4V. The corrosion resistance of titanium alloys were investigated through open circuit potential (OCP), potentiodynamic polarization measurements and optical microscope (OM). A high corrosion resistance was obtained for all alloys due to the stable passive film formed on their surfaces. The new present alloys are promising metallic biomaterials for the future, owing to their very low elastic modulus and good corrosion resistance capabilities.

Keywords: titanium alloys, corrosion resistance, Ringer’s solution, electrochemical corrosion

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Authors: M. Rilliard

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Based on a Multiliteracies-inspired and sociolinguistically-informed advanced French composition class, this study employed autobiographical narratives from speakers traditionally considered non-legitimate models for L2 teaching purposes of inspiring students to develop an authentic L2 voice and to see themselves as legitimate L2 speakers. Students explored their L2 identities in French through a self-inspired fictional character. Two autobiographical narratives of identity quest by non-traditional French speakers provided them guidance through this process: the novel Le Bleu des Abeilles (2013) and the film Qu’Allah Bénisse la France (2014). Written and French oral productions for different genres, as well as metalinguistic reflections in English, were collected and analyzed. Results indicate that ideas and materials that were relatable to students, namely relatable experiences and relatable language, were most useful to them in developing their L2 voices and achieving authentic and legitimate L2 speakership. These results point towards the benefits of using non-traditional speakers as pedagogical models, as they serve to legitimize students’ sense of their own L2-speakership, which ultimately leads them towards a better, more informed, mastery of the language.

Keywords: foreign language classroom, L2 identity, L2 learning and teaching, L2 writing, sociolinguistics

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Authors: Khalid Ahmed Eldwaib

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In this study, Al-Mg alloy 5052 was used as the testing material. Corrosion fatigue life was studied for the alloy in 3.5% NaCl (pH=1, 3, 5, 7, 9, and 11), and 3.5% NaCl (pH=1) with inhibitors. The compound inhibitors were composed mainly of phosphate (PO4³-), adding a certain proportion of other nontoxic inhibitors so as to select alternatives to environmentally hazardous chromate (Cr2O7²-). The inhibitors were sodium dichromate Na2Cr2O7, sodium phosphate Na3PO4, sodium molybdate Na2MoO4, and sodium citrate Na3C6H5O7. The total amount of inhibiting pigments was at different concentrations (250,500,750, and 1000 ppm) in the solutions. Corrosion fatigue behavior was studied by using plane-bending corrosion fatigue machine with stress ratio R=0.5 and under the constant frequency of 13.3 Hz. Results show that in 3.5% NaCl the highest fatigue life (number of cycles to failure Nf) is obtained at pH=5 where the oxide film on aluminum has very low solubility, and the lowest number of cycles is obtained at pH=1, where the media is too aggressive (extremely acidic). When the concentration of inhibitor increases the cycles to failure increase. The surface morphology and fracture section of the specimens had been characterized through scanning electron microscope (SEM).

Keywords: Al-Mg alloy 5052, corrosion, fatigue, inhibitors

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Authors: Leila Ayat, Afak Meftah

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Amorphous-silicon alloys have great promise as low cost solar cell materials. They have excellent photo-conductivity and high optical absorption to sunlight. Now PIN a-Si:H based solar cells are widely used in power generation modules. However, to improve the performance of these cells further, a better fundamental under-standing of the factors limiting cell performance in the homo junction PIN structure is necessary. In this paper we discuss the sensitivity of light J-V characteristics to various device and material parameters in PIN homo junction solar cells. This work is a numerical simulation of the output parameters of a PIN a-Si:H solar cell under AM1.5 spectrum. These parameters are the short circuit current (Jsc), the open circuit voltage (Voc), the fill factor (FF), the conversion efficiency. The simulation was performed with SCAPS-1D software version 3.3 developed at ELIS in Belgium by Marc Burgelman et al. The obtained results are in agreement with experiment. In addition, the effect of the thickness, doping density, capture cross sections of the gap states and the band microscopic mobilities on the output parameters of the cell are also presented.

Keywords: amorphous silicon p-i-n junctions, thin film, solar cells, sensitivity

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Authors: Mary Okocha

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Over the past two decades, since it came into existence, the Nigerian film industry, also known as Nollywood, has taken a global phenomenon and is reckoned with by most Africans at home or in Diaspora. The themes portrayed in these movies are supposedly made to reflect the social, cultural, economic and religious situations prevalent in Nigeria as well as most African countries. Stories are especially effective in cultural processes because they involve audiences by entertaining them and by challenging them to make sense of the story's symbolic meaning. Using two Nigerian movies, Mammi and Arugba, this paper aims at critically examining the pressures that society places on the Nigerian female and how this same society fails to lend a helping hand in making this possible, but rather turns back to heap blames and question the virtues of the females if, on the long run, these expectations are not met inconsiderate of the circumstances that stood in their ways and how these pressures have stood against the progress of the Nigerian woman. Furthermore, female respondents will be randomly selected and their opinions will be sorted through questionnaires to see what they feel could be done to help in overcoming these challenges and how the movie industry can help in repositioning the Nigerian woman.

Keywords: Nollywood, Nigerian films, audiences, Nigerian woman, Nigerian society, female respondents, repositioning women, societal pressures

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Authors: Georgeta Voicu, Cristina Daniela Ghitulica, Andreia Cucuruz, Cristina Busuioc

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In the field of tissue engineering, the compositional and microstructural features of the employed materials play an important role, with implications on the mechanical and biological behaviour of the medical devices. In this context, the development of apatite - natural biopolymer composites represents a choice of many scientific groups. Thus, hydroxyapatite powders were synthesized by a wet method, namely co-precipitation, starting from high purity reagents (CaO, MgO, and H3PO4). Moreover, the substitution of calcium with magnesium have been approached, in the 5 - 10 wt.% range. Afterward, the phosphate powders were integrated in two types of composites with chitosan, different from morphological point of view. First, 3D porous scaffolds were obtained by a freeze-drying procedure. Second, uniform, compact films were achieved by film casting. The influence of chitosan molecular weight (low, medium and high), as well as apatite powder to polymer ratio (1:1 and 1:2) on the morphological properties, were analysed in detail. In conclusion, the reported biocomposites, prepared by a straightforward route are suitable for bone substitution or repairing applications.

Keywords: bone reconstruction, chitosan, composite scaffolds, hydroxyapatite

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Authors: Anil Kawan, Soon Jae Yu, Jong Min Park

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GaN-based 365 nm wavelength ultraviolet (UV) light emitting diodes (LED) have various applications: curing, molding, purification, deodorization, and disinfection etc. However, their usage is limited by very low output power, because of the light absorption in the GaN layers. In this study, we demonstrate a method utilizing removal of 365 nm absorption layer buffer GaN and thinning the n-type GaN so as to improve the light extraction efficiency of the GaN-based 365 nm UV LED. The UV flip chip LEDs of chip size 1.3 mm x 1.3 mm were fabricated using GaN epilayers on a sapphire substrate. Via-hole n-type contacts and highly reflective Ag metal were used for efficient light extraction. LED wafer was aligned and bonded to AlN carrier wafer. To improve the extraction efficiency of the flip chip LED, sapphire substrate and absorption layer buffer GaN were removed by using laser lift-off and dry etching, respectively. To further increase the extraction efficiency of the LED, exposed n-type GaN thickness was reduced by using inductively coupled plasma etching.

Keywords: extraction efficiency, light emitting diodes, n-GaN thinning, ultraviolet

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Authors: Geon Bae, Cheol Hee Moon

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Organic Light Emitting Diodes (OLEDs) are being developed rapidly as next-generation displays due to their self-luminous and flexible characteristics. OLEDs are highly susceptible to moisture and oxygen due to their structural properties. Thus, requiring a high level of encapsulation technology. Recently, encapsulation technology such as Thin Film Encapsulation (TFE) has been developed for OLED, but it is not perfect to prevent moisture permeation on the side. In this study, we propose OLED encapsulation method using Low melting Point Alloy (LMPA). The LMPA line was designed in square box shape on the outer edge of the device and was formed by screen printing method. To determine if LMPA has an effect on OLED, we fabricated solution processed OLEDs with a square-shaped LMPA line and evaluate the I-V-L characteristics of the OLEDs. Also, the resistance characteristic of the LMPA line was observed by repeatedly bending the LMPA line. It is expected that LMPA encapsulation will have a great advantage in shortening the process time and cost reduction.

Keywords: OLED, encapsulation, LMPA, solution process

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Authors: Kudakwashe Diana Nyamugure

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Engine design has evolved to suit new industry standards of smaller compact designs that operate at high temperatures and even higher stress loads. Research has proven that the interaction of the bearing surface and the lubrication film is affected by the bearing's surface texture, geometry, and dimensional tolerances. The challenge now for the automotive manufacturing industry is to understand which processes can be applied on bearing surfaces to reduce the 65% energy loss in engines, 15% of which is caused by friction. This paper will discuss a post grinding process known as microfinishing which optimises the characteristics of a manufactured surface such as roughness, profile, and waviness. Microfinishing is becoming an increasing trend within the automotive industry and has so far been applied on high performance and mass production crank or cam bearing surfaces in bid of friction reduction and extended engine service life. In the near future, microfinishing will be applied to more engine components because of the stringent environmental regulations demands on fuel consumption, reliability, power, and service life of engine components.

Keywords: bearings, tribology, friction reduction, energy efficiency

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Authors: Niloofar Alipoormazandarani

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The rift environmental, efficiency and being environmental-friendly of these innovative food packaging in edible films made them as an alternative to synthetic packages. This issue has been widely studied in this experiment. Some of the greatest advances in food packaging industry is associated with nanotechnology. Recently, a polysaccharide extracted from the cell wall of soybean cotyledons: A soluble soybean polysaccharide (SSPS), a pectin-like structure. In this study, the addition (0%, 1%, 3%, and 5%) of nano silica dioxide (SiO2) film is examined SSPS in different features. The research aims to investigate the effect of nano-SiO2 on the physicochemical and electromagnetic properties of the SSPS films were sonicated and then heated to the melting point, besides the addition of plasticizer. After that, it has been cooled into the room temperature and were dried with Casting method. In final examinations,improvement in Moisture Content and Water Absorption was observed with a significant decrease.Also, in Color measurements there were some obvious differences. These reports indicate that the incorporation of nano-SiO2 and SSPS has the power to be extensively used in pharmaceutical and food packaging industry as well.

Keywords: SSPS, NanoSiO2, food packaging, renewable films

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Authors: Jalil Badamfirooz

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Soil wind erosion has a negative impact on the environment. Mulching is one of the most efficient soil protection techniques. Bitumen emulsion has recently been utilized as a soil cover that is sprayed directly over the soil and forms a thin film. The thin coating of bitumen emulsion prevents soil erosion and keeps moisture in the soil. Besides, some compounds release into the soil and cause environmental problems. In the present study, the effect of bitumen emulsion on the release of polycyclic aromatic hydrocarbons (PAHs) into the soil is studied in an arid land located in the central part of Iran. The soil was Loamy-Sand and saline with a pH of 8.03. Bitumen emulsion was used in this study as mulch at a rate of 4 L m2. The effect of this mulch on soil properties was investigated after 6 months of mulch application. Then PAHs concentrations were determined in samples collected from different depths in bitumen emulsion sprayed and control soils. In general, bitumen emulsion application on soil led to a significant increase in some PAHs, which was higher than soil pollution standards critical level of pollution for commerce, groundwater protection, pasture forest, and park and residence uses.

Keywords: mulch, bitumen emulsion, arid land, PAH

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Authors: Thiago E. Goto, Carla C. Lopes, Helena B. Nader, Anielle C. A. Silva, Noelio O. Dantas, José R. Siqueira Jr., Luciano Caseli

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Quantum dots (QD) are semiconductor nanocrystals that can be employed in biological research as a tool for fluorescence imagings, having the potential to expand in vivo and in vitro analysis as cancerous cell biomarkers. Particularly, cadmium selenide (CdSe) magic-sized quantum dots (MSQDs) exhibit stable luminescence that is feasible for biological applications, especially for imaging of tumor cells. For these facts, it is interesting to know the mechanisms of action of how such QDs mark biological cells. For that, simplified models are a suitable strategy. Among these models, Langmuir films of lipids formed at the air-water interface seem to be adequate since they can mimic half a membrane. They are monomolecular films formed at liquid-gas interfaces that can spontaneously form when organic solutions of amphiphilic compounds are spread on the liquid-gas interface. After solvent evaporation, the monomolecular film is formed, and a variety of techniques, including tensiometric, spectroscopic and optic can be applied. When the monolayer is formed by membrane lipids at the air-water interface, a model for half a membrane can be inferred where the aqueous subphase serve as a model for external or internal compartment of the cell. These films can be transferred to solid supports forming the so-called Langmuir-Blodgett (LB) films, and an ampler variety of techniques can be additionally used to characterize the film, allowing for the formation of devices and sensors. With these ideas in mind, the objective of this work was to investigate the specific interactions of CdSe MSQDs with tumorigenic and non-tumorigenic cells using Langmuir monolayers and LB films of lipids and specific cell extracts as membrane models for diagnosis of cancerous cells. Surface pressure-area isotherms and polarization modulation reflection-absorption spectroscopy (PM-IRRAS) showed an intrinsic interaction between the quantum dots, inserted in the aqueous subphase, and Langmuir monolayers, constructed either of selected lipids or of non-tumorigenic and tumorigenic cells extracts. The quantum dots expanded the monolayers and changed the PM-IRRAS spectra for the lipid monolayers. The mixed films were then compressed to high surface pressures and transferred from the floating monolayer to solid supports by using the LB technique. Images of the films were then obtained with atomic force microscopy (AFM) and confocal microscopy, which provided information about the morphology of the films. Similarities and differences between films with different composition representing cell membranes, with or without CdSe MSQDs, was analyzed. The results indicated that the interaction of quantum dots with the bioinspired films is modulated by the lipid composition. The properties of the normal cell monolayer were not significantly altered, whereas for the tumorigenic cell monolayer models, the films presented significant alteration. The images therefore exhibited a stronger effect of CdSe MSQDs on the models representing cancerous cells. As important implication of these findings, one may envisage for new bioinspired surfaces based on molecular recognition for biomedical applications.

Keywords: biomembrane, langmuir monolayers, quantum dots, surfaces

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Authors: Mahmoudi Noureddine

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The glass fiber (GF) reinforced polyimide (PL) composites filled with graphite powders were fabricated by means of hot press molding technique. The friction and wear properties of the resulting composites sliding against GCr15 steel were investigated on a model ring-on-block test rig at dry sliding condition. The wear mechanisms were also discussed, based on scanning electron microscopic examination of the worn surface of the PL composites and the transfer film formed on the counterpart. With the increasing normal loads, the friction coefficient of the composites increased under the dry sliding, owing to inconsistent influences of shear strength and real contact areas. Experimental results revealed that the incorporation of graphite significantly improve the wear resistance of the glass fibers reinforced polyimide composites. For best combination of friction coefficient and wear rate, the optimal volume content of graphite in the composites appears to be 45 %. It was also found that the tribological properties of the glass fiber reinforced PL composites filled with graphite powders were closely related with the sliding condition such as sliding rate and applied load.

Keywords: composites, fiber, friction, wear

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Authors: Nadiah Yola Putri, Nesia Putri Sharfina, Traviata Prakarti

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This paper is a literature review presented descriptively to review the concept of green building to face the challenge of sustainable development and food in urban areas. In this paper, researchers initiated the concept of green building with sky farming method. Sky farming use vertical landscape system in order to realizing food self-sufficient green city. Sky farming relying on plantings and irrigation system efficiency in the building which is adopted the principles of green building. Planting system is done by applying hydroponic plants with Nutrient Film Technique (NFT) using energy source of solar cell and grey water from the processing of waste treatment plant. The application of sky farming in urban areas can be a recommendation for the design of environmental-friendly construction. In order to keep the land and distance efficiency, this system is a futuristic idea that would be the connector of human civilization in the future.

Keywords: green building, urban area, sky farming, vertical landscape

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Authors: A. Hamam, D. Oukil, A. Dib, L. Makhloufi

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The aim of this work is to synthesize modified Polypyrrole films (PPy) containing nanoparticles of copper oxides onto a non conducting cellulosic substrate. Firstly, the chemical polymerization of polypyrrole onto cellulosic substrate is carried out using FeCl3 as an oxidant and Pyrrole as monomer. Different parameters were optimized (monomer concentration, duration of the experiment, nature of supporting electrolyte, temperature, etc.) in order to obtain films with different thickness and different morphologies. Thickness and topography of different PPy deposits were estimated by a profilometer apparatus. The electrochemical reactivity of the obtained electrodes were tested by cyclic voltammetry technique (CV) and electrochemical impedance spectroscopy (EIS). Secondly, the modification of the PPy film surface by incorporation of copper oxide nanonoparticles is conducted by applying a galvanostatic procedure from CuCl2 solution. Surface characterization has been carried out using scanning microscope (SEM) coupled with energy dispersive X-ray analysis (EDX), Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The analysis showed the presence of the copper oxide nanoparticles (CuO) in the polymer films with dimensions less than 50 nm.

Keywords: polypyrrole, modified electrode, cellulosic substrate, copper oxide

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Authors: M. Naveed Yasin, Robert Brooke, Andrew Chan, Geoffrey I. N. Waterhouse, Drew Evans, Darren Svirskis, Ilva D. Rupenthal

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Poly(3,4-ethylenedioxythiophene) (PEDOT) is a robust conducting polymer (CP) exhibiting high conductivity and environmental stability. It can be synthesized by either chemical, electrochemical or vapour phase polymerization (VPP). Dexamethasone sodium phosphate (dexP) is an anionic drug molecule which has previously been loaded onto PEDOT as a dopant via electrochemical polymerisation; however this technique requires conductive surfaces from which polymerization is initiated. On the other hand, VPP produces highly organized biocompatible CP structures while polymerization can be achieved onto a range of surfaces with a relatively straight forward scale-up process. Following VPP of PEDOT, dexP can be loaded and subsequently released via ion-exchange. This study aimed at preparing and characterising both non-porous and porous VPP PEDOT structures including examining drug loading and release via ion-exchange. Porous PEDOT structures were prepared by first depositing a sacrificial polystyrene (PS) colloidal template on a substrate, heat curing this deposition and then spin coating it with the oxidant solution (iron tosylate) at 1500 rpm for 20 sec. VPP of both porous and non-porous PEDOT was achieved by exposing to monomer vapours in a vacuum oven at 40 mbar and 40 °C for 3 hrs. Non-porous structures were prepared similarly on the same substrate but without any sacrificial template. Surface morphology, compositions and behaviour were then characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) respectively. Drug loading was achieved by 50 CV cycles in a 0.1 M dexP aqueous solution. For drug release, each sample was exposed to 20 mL of phosphate buffer saline (PBS) placed in a water bath operating at 37 °C and 100 rpm. Film was stimulated (continuous pulse of ± 1 V at 0.5 Hz for 17 mins) while immersed into PBS. Samples were collected at 1, 2, 6, 23, 24, 26 and 27 hrs and were analysed for dexP by high performance liquid chromatography (HPLC Agilent 1200 series). AFM and SEM revealed the honey comb nature of prepared porous structures. XPS data showed the elemental composition of the dexP loaded film surface, which related well with that of PEDOT and also showed that one dexP molecule was present per almost three EDOT monomer units. The reproducible electroactive nature was shown by several cycles of reduction and oxidation via CV. Drug release revealed success in drug loading via ion-exchange, with stimulated porous and non-porous structures exhibiting a proof of concept burst release upon application of an electrical stimulus. A similar drug release pattern was observed for porous and non-porous structures without any significant statistical difference, possibly due to the thin nature of these structures. To our knowledge, this is the first report to explore the potential of VPP prepared PEDOT for stimuli-responsive drug delivery via ion-exchange. The produced porous structures were ordered and highly porous as indicated by AFM and SEM. These porous structures exhibited good electroactivity as shown by CV. Future work will investigate porous structures as nano-reservoirs to increase drug loading while sealing these structures to minimize spontaneous drug leakage.

Keywords: PEDOT for ion-exchange drug delivery, stimuli-responsive drug delivery, template based porous PEDOT structures, vapour phase polymerization of PEDOT

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Authors: Sicheng Liu

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Based on the key issue of the current fourth world studies, the article aims to analyze the features of character-settings in Chinese ethnic minority films. As a generalizable transformation, this feature progresses from a microcosmic representation. It argues that, as the mediation, films note down the current state of people and their surroundings, while the ‘fourth world’ theorization (or the fourth cinema) provides a new perspective to ethnic minority topics in China. Like the ‘fourth cinema’ focusing on the depiction of indigeneity groups, the ethnic minority films portrait the non-Han nationalities in China. Both types possess the motif of returning history-writing to the minority members’ own hand. In this article, the discussion entirely involves three types of cinematic role-settings in Chinese minority themed films, which illustrates that, similar to the creative principle of the fourth film, the themes and narratives of these films are becoming more individualized, with more concern to minority grassroots.

Keywords: 'fourth world', Chinese ethnic minority films, ethnicity and culture reflection, 'mother tongue' (muyu), highlighting to individual spiritual

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Authors: Najat El-Kurdi, Sherif Hammad, Mohamed Ghazi, Sahar El-Shatoury, Khaled Zakaria

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The increasing number of plastic production and its importance to humanity in daily life made it a headache to the planet earth. The persistence of plastic wastes in the environment formed a serious problem. They are prominent with their capability to resist microbial degradation for decades. Thus, it was crucial to find ways to eliminate the plastics without depending on conventional recycling methods, which causes the formation of more hazardous compounds and doubles the problem. In this paper, mealworms were fed with a mixture of plastic wastes such as plastic bags, Styrofoam, PE foam, and plastic tarpaulins film as the sole food source for a month. Frass was collected at the end of the test and examined using FTIR analysis. Also, the gut bacteria were isolated and identified using 16S rRNA. The results show the mineralization of plastic in the frass of plastic-fed worms when compared to control. The 16S rRNA and the BLAST analysis showed that the obtained isolate belongs to the genus Bacillus Sp especially Bacillus subtilis. Phylogenetic analysis showed their relatedness to the other Bacillus species in the NCBI database.

Keywords: mealworm, waste management, plastic-degrading bacteria, gut microbiome, Bacillus sp

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Authors: Janella Salamania, Marcedon Fernandez, Matthew Villanueva Henry Ramos

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Titanium nitrite (TiN) a popular functional and decorative coating because of its golden yellow color, high hardness and superior wear resistance. It is also being studied as a diffusion barrier in integrated circuits due to its known chemical stability and low resistivity. While there have been numerous deposition methods done for TiN, most required the heating of substrates at high temperatures. In this work, TiN films are deposited on silicon (111) and (100) substrates without substrate heating using a patented magnetized sheet plasma source. Films were successfully deposited without substrate heating at various target bias, while maintaining a constant 25% N2 to Ar ratio, and deposition of time of 30 minutes. The resulting films exhibited a golden yellow color which is characteristic of TiN. X-ray diffraction patterns show the formation of TiN predominantly oriented in the (111) direction regardless of substrate used. EDX data also confirms the 1:1 stoichiometry of titanium an nitrogen. Ellipsometry measurements estimate the thickness to range from 28 nm to 33 nm. SEM images were also taken to observe the morphology of the film.

Keywords: coatings, nitrides, coatings, reactive magnetron sputtering, thin films

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Authors: Jafar Akbari, Masoud Rismanchian, Samira Ramezani

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Purpose: The photocatalytic degradation of pollutants is a novel technology with various advantages such as high efficiency and energy saving. In this research, the effects of operational variables on the photocatalytic efficiency of TiO₂ coated on nickel foam in the removal of toluene from the simulated indoor air have been investigated. Methods: TiO₂ film were prepared via the sol-gel method and coated on nickel foam. The characteristics and morphology were found using XRD, SEM, and BET technique. Then, the effects of relative humidity, UV-A intensity, the initial toluene concentration, TiO₂ loading, and the air circulation velocity on the photocatalytic degradation rate have been evaluated. Results: The optimal degradation of toluene has been achieved with loading 4.35 g TiO2 on the foam, 30% RH, 5.4 µW.cm−2 UV-A intensity, and 20 ppm initial concentration in the air circulation velocity of 0.15 fpm. Conclusion: The changes of toluene photocatalytic degradation rate have been studied at various times. Also, the kinetic behavior of toluene photocatalytic degradation has been investigated using Langmuir-Hinshelwood (L-H) model.

Keywords: photocatalytic degradation, operational variables, tio₂, nickel foam, gaseous toluene, nanotechnology

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Authors: S. S. Kharintsev, E. A. Chernykh, S. K. Saikin, A. I. Fishman, S. G. Kazarian

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Recent advances in improving information storage performance are inseparably linked with circumvention of fundamental constraints such as the supermagnetic limit in heat assisted magnetic recording, charge loss tolerance in solid-state memory and the Abbe’s diffraction limit in optical storage. A substantial breakthrough in the development of nonvolatile storage devices with dimensional scaling has been achieved due to phase-change chalcogenide memory, which nowadays, meets the market needs to the greatest advantage. A further progress is aimed at the development of versatile nonvolatile high-speed memory combining potentials of random access memory and archive storage. The well-established properties of light at the nanoscale empower us to use them for recording optical information with ultrahigh density scaled down to a single molecule, which is the size of a pit. Indeed, diffraction-limited optics is able to record as much information as ~1 Gb/in2. Nonlinear optical effects, for example, two-photon fluorescence recording, allows one to decrease the extent of the pit even more, which results in the recording density up to ~100 Gb/in2. Going beyond the diffraction limit, due to the sub-wavelength confinement of light, pushes the pit size down to a single chromophore, which is, on average, of ~1 nm in length. Thus, the memory capacity can be increased up to the theoretical limit of 1 Pb/in2. Moreover, the field confinement provides faster recording and readout operations due to the enhanced light-matter interaction. This, in turn, leads to the miniaturization of optical devices and the decrease of energy supply down to ~1 μW/cm². Intrinsic features of light such as multimode, mixed polarization and angular momentum in addition to the underlying optical and holographic tools for writing/reading, enriches the storage and encryption of optical information. In particular, the finite extent of the near-field penetration, falling into a range of 50-100 nm, gives the possibility to perform 3D volume (layer-to-layer) recording/readout of optical information. In this study, we demonstrate a comprehensive evidence of isotropic-to-homeotropic phase transition of the azobenzene-functionalized polymer thin film exposed to light and dc electric field using near-field optical microscopy and scanning capacitance microscopy. We unravel a near-field Raman dichroism of a sub-10 nm thick epoxy-based side-chain azo-polymer films with polarization-controlled tip-enhanced Raman scattering. In our study, orientation of azo-chromophores is controlled with a bias voltage gold tip rather than light polarization. Isotropic in-plane and homeotropic out-of-plane arrangement of azo-chromophores in glassy environment can be distinguished with transverse and longitudinal optical near-fields. We demonstrate that both phases are unambiguously visualized by 2D mapping their local dielectric properties with scanning capacity microscopy. The stability of the polar homeotropic phase is strongly sensitive to the thickness of the thin film. We make an analysis of α-transition of the azo-polymer by detecting a temperature-dependent phase jump of an AFM cantilever when passing through the glass temperature. Overall, we anticipate further improvements in optical storage performance, which approaches to a single molecule level.

Keywords: optical memory, azo-dye, near-field, tip-enhanced Raman scattering

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Authors: A.G. S. Aldajani, N. Smida, M. G. Althobaiti, B. Zaidi

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In order to exploit the good electrical properties of anthracene and the excellent properties of fluorescein, new hybrid material has been synthesized (An-Fl). Current-voltage measurements were done on a new single-layer ITO/An-FL/Al device of typically 100 nm thickness. Atypical diode behavior is observed with a turn-on voltage of 4.4 V, a dynamic resistance of 74.07 KΩ and a rectification ratio of 2.02 due to unbalanced transport. Results show also that the current-voltage characteristics present three different regimes of the power-law (J~Vᵐ) for which the conduction mechanism is well described with space-charge-limited current conduction mechanism (SCLC) with a charge carrier mobility of 2.38.10⁻⁵cm2V⁻¹S⁻¹. Moreover, the electrical transport properties of this device have been carried out using a dependent frequency study in the range (50 Hz–1.4 MHz) for different applied biases (from 0 to 6 V). At lower frequency, the σdc values increase with bias voltage rising, supporting that the mobile ion can hop successfully to its nearest vacant site. From σac and impedance measurements, the equivalent electrical circuit is evidenced, where the conductivity process is coherent with an exponential trap distribution caused by structural defects and/or chemical impurities.

Keywords: semiconducting polymer, conductivity, SCLC, impedance spectroscopy

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Authors: Guankai Lin, Wei Tong, Hong Zhu

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The electric current induced Joule heating effects have been investigated in La₀.₈Ba₀.₂MnO₃ ultrathin films deposited on LaAlO₃(001) single crystal substrate with smaller lattice constant by using the sol-gel method. By applying moderate bias currents (~ 10 mA), it is found that Joule self-heating simply gives rise to a temperature deviation between the thermostat and the test sample, but the intrinsic ρ(T) relationship measured at a low current (0.1 mA) changes little. However, it is noteworthy that the low-temperature transport behavior degrades from metallic to insulating state after applying higher bias currents ( > 31 mA) in a vacuum. Furthermore, metallic transport can be recovered by placing the degraded film in air. The results clearly suggest that the oxygen vacancy in the La₀.₈Ba₀.₂MnO₃ films is controllable in different atmospheres, particularly with the aid of the Joule self-heating. According to the SEM images, we attribute the controlled oxygen vacancy to the nano-sized labyrinth pattern of the films, where the large surface-to-volume ratio plays a curial role.

Keywords: controlling oxygen vacancy, joule self-heating, manganite, sol-gel method

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Authors: Yagya Raj Pandeya, Joonwhoan Lee

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The dynamic behavior of music and video makes it difficult to evaluate musical instrument playing in a video by computer system. Any television or film video clip with music information are rich sources for analyzing musical instruments using modern machine learning technologies. In this research, we integrate the audio and video information sources using convolutional neural network (CNN) and pass network learned features through recurrent neural network (RNN) to preserve the dynamic behaviors of audio and video. We use different pre-trained CNN for music and video feature extraction and then fine tune each model. The music network use 2D convolutional network and video network use 3D convolution (C3D). Finally, we concatenate each music and video feature by preserving the time varying features. The long short term memory (LSTM) network is used for long-term dynamic feature characterization and then use late fusion with generalized mean. The proposed network performs better performance to recognize the musical instrument using audio-video multimodal neural network.

Keywords: multimodal, 3D convolution, music-video feature extraction, generalized mean

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Authors: Yousif Mohamed Y. Abdallah, Mommen A. Alkhir, Amel S. Algaddal

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This was experimental study conducted to study segmentation of brain in MRI images using edge detection and morphology filters. For brain MRI images each film scanned using digitizer scanner then treated by using image processing program (MatLab), where the segmentation was studied. The scanned image was saved in a TIFF file format to preserve the quality of the image. Brain tissue can be easily detected in MRI image if the object has sufficient contrast from the background. We use edge detection and basic morphology tools to detect a brain. The segmentation of MRI images steps using detection and morphology filters were image reading, detection entire brain, dilation of the image, filling interior gaps inside the image, removal connected objects on borders and smoothen the object (brain). The results of this study were that it showed an alternate method for displaying the segmented object would be to place an outline around the segmented brain. Those filters approaches can help in removal of unwanted background information and increase diagnostic information of Brain MRI.

Keywords: improvement, brain, matlab, markers, boundaries

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Authors: Vivek Garg, Brajendra S. Sengar, Gaurav Siddharth, Nisheka Anadkat, Amitesh Kumar, Shailendra Kumar, Shaibal Mukherjee

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CuInGaSe (CIGSe) is the dominant thin film solar cell technology. The band alignment of Buffer/CIGSe interface is one of the most crucial parameters for solar cell performance. In this article, the valence band offset (VBOff) and conduction band offset (CBOff) values of Cu(In0.70Ga0.30)Se/ 1 at.% Ga: Mg0.25Zn0.75O (GMZO) heterojunction, grown by dual ion beam sputtering system (DIBS), are calculated to understand the carrier transport mechanism at the heterojunction for the realization of all sputtered buffer-less solar cells. To determine the valence band offset (VBOff), ∆E_V at GMZO/CIGSe heterojunction interface, the standard method based on core-level photoemission is utilized. The value of ∆E_V can be evaluated by considering common core-level peaks. In our study, the values of (Valence band onset)VBOn, obtained by linear extrapolation method for GMZO and CIGSe films are calculated to be 2.86 and 0.76 eV. In the UPS spectra peak positions of Se 3d is observed in UPS spectra at 54.82 and 54.7 eV for CIGSe film and GMZO/CIGSe interface respectively, while the peak position of Mg 2p is observed at 50.09 and 50.12 eV for GMZO and GMZO/CIGSe interface respectively. The optical band gap of CIGSe and GMZO are obtained from absorption spectra procured from spectroscopic ellipsometry are 1.26 and 3.84 eV respectively. The calculated average values of ∆E_v and ∆E_C are estimated to be 2.37 and 0.21 eV, respectively, at room temperature. The calculated positive conduction band offset termed as a spike at the absorber junction is the required criterion for the high-efficiency solar cells for the efficient charge extraction from the junction. So we can conclude that the above study confirms GMZO thin films grown by the dual ion beam sputtering system are the suitable candidate for the CIGSe thin films based ultra-thin buffer-less solar cells. We investigated the band-offset properties at the GMZO/CIGSe heterojunction to verify the suitability of the GMZO for the realization of the buffer-less solar cells. The calculated average values of ∆E_V and ∆E_C are estimated to be 2.37 and 0.21 eV, respectively, at room temperature. The calculated positive conduction band offset termed as a spike at the absorber junction is the required criterion for the high-efficiency solar cells for the efficient charge extraction from the junction. So we can conclude that the above study confirms GMZO thin films grown by the dual ion beam sputtering system are the suitable candidate for the CIGSe thin films based ultra-thin buffer-less solar cells. Acknowledgment: We are thankful to DIBS, EDX, and XRD facility equipped at Sophisticated Instrument Centre (SIC) at IIT Indore. The authors B.S.S and A.K acknowledge CSIR and V.G acknowledge UGC, India for their fellowships. B.S.S is thankful to DST and IUSSTF for BASE Internship Award. Prof. Shaibal Mukherjee is thankful to DST and IUSSTF for BASE Fellowship and MEITY YFRF award. This work is partially supported by DAE BRNS, DST CERI, and DST-RFBR Project under India-Russia Programme of Cooperation in Science and Technology. We are thankful to Mukul Gupta for SIMS facility equipped at UGC-DAE Indore.

Keywords: CIGSe, DIBS, GMZO, solar cells, UPS

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Authors: Pooja Seth, Shruti Aggarwal

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The Europium (Eu) doped (0.02-0.1 wt %) lithium fluoride (LiF) crystal in the form of multicrystalline sheet was gown by the edge defined film fed growth (EFG) technique. Crystals were grown in argon gas atmosphere using graphite crucible and stainless steel die. The systematic incorporation of Eu inside the host LiF lattice was confirmed by X-ray diffractometry. Thermoluminescence (TL) glow curve was recorded on annealed (AN) crystals after irradiation with a gamma dose of 15 Gy. The effect of different concentration of Eu in enhancing the thermoluminescence (TL) intensity of LiF was studied. The normalized peak height of the Eu-doped LiF crystal was nearly 12 times that of the LiF crystals. The optimized concentration of Eu in LiF was found to be 0.05wt% at which maximum TL intensity was observed with main TL peak positioned at 185 °C. At higher concentration TL intensity decreases due to the formation of precipitates in the form of clusters or aggregates. The nature of the energy traps in Eu doped LiF was analysed through glow curve deconvolution. The trap depth was found to be in the range of 0.2 – 0.5 eV. These results showed that doping with Eu enhances the TL intensity by creating more defect sites for capturing of electron and holes during irradiation which might be useful for dosimetry application.

Keywords: thermoluminescence, defects, gamma radiation, crystals

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Authors: Nisha Prakash, Kritika Anand, Arun Barvat, Prabir Pal, Sonachand Adhikari, Suraj P. Khanna

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Group-III nitride semiconductors (GaN, AlN, InN and their ternary and quaternary compounds) have attracted a great deal of attention for the development of high-performance Ultraviolet (UV) photodetectors. Any midgap defect states in the epitaxial grown film have a direct influence on the photodetectors responsivity. The proportion of the midgap defect states can be controlled by the growth parameters. To study this we have grown high quality epitaxial GaN films on MOCVD- grown GaN template using plasma-assisted molecular beam epitaxy (PAMBE) with different growth parameters. Optical and electrical properties of the films were characterized by room temperature photoluminescence and photoconductivity measurements, respectively. The observed persistent photoconductivity behaviour is proportional to the yellow luminescence (YL) and the absolute responsivity has been found to decrease with decreasing YL. The results will be discussed in more detail later.

Keywords: gallium nitride, plasma-assisted molecular beam epitaxy, photoluminescence, photoconductivity, persistent photoconductivity, yellow luminescence

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Authors: Roman Major, Klaudia Trembecka- Wojciga, Juergen Markus Lackner, Boguslaw Major

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The future and the development of science is therefore seen in interdisciplinary areas such as bio medical engineering. Self-assembled structures, similar to stem cell niches would inhibit fast division process and subsequently capture the stem cells from the blood flow. By means of surface topography and the stiffness as well as micro structure progenitor cells should be differentiated towards the formation of endothelial cells monolayer which effectively will inhibit activation of the coagulation cascade. The idea of the material surface development met the interest of the clinical institutions, which support the development of science in this area and are waiting for scientific solutions that could contribute to the development of heart assist systems. This would improve the efficiency of the treatment of patients with myocardial failure, supported with artificial heart assist systems. Innovative materials would enable the redesign, in the post project activity, construction of ventricular heart assist.

Keywords: bio-inspired materials, electron microscopy, haemocompatibility, niche-like structures, thin coatings

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Authors: Shweta Pinjarkar, Shrutika Yawale, Mayuri Patil, Reshma Adagale

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Face recognition is the technique which can be applied to the wide variety of problems like image and film processing, human computer interaction, criminal identification etc. This has motivated researchers to develop computational models to identify the faces, which are easy and simple to implement. In this, demonstrates the face recognition system in android device using eigenface. The system can be used as the base for the development of the recognition of human identity. Test images and training images are taken directly with the camera in android device.The test results showed that the system produces high accuracy. The goal is to implement model for particular face and distinguish it with large number of stored faces. face recognition system detects the faces in picture taken by web camera or digital camera and these images then checked with training images dataset based on descriptive features. Further this algorithm can be extended to recognize the facial expressions of a person.recognition could be carried out under widely varying conditions like frontal view,scaled frontal view subjects with spectacles. The algorithm models the real time varying lightning conditions. The implemented system is able to perform real-time face detection, face recognition and can give feedback giving a window with the subject's info from database and sending an e-mail notification to interested institutions using android application. Face recognition is the technique which can be applied to the wide variety of problems like image and film processing, human computer interaction, criminal identification etc. This has motivated researchers to develop computational models to identify the faces, which are easy and simple to implement. In this , demonstrates the face recognition system in android device using eigenface. The system can be used as the base for the development of the recognition of human identity. Test images and training images are taken directly with the camera in android device.The test results showed that the system produces high accuracy. The goal is to implement model for particular face and distinguish it with large number of stored faces. face recognition system detects the faces in picture taken by web camera or digital camera and these images then checked with training images dataset based on descriptive features. Further this algorithm can be extended to recognize the facial expressions of a person.recognition could be carried out under widely varying conditions like frontal view,scaled frontal view subjects with spectacles. The algorithm models the real time varying lightning conditions. The implemented system is able to perform real-time face detection, face recognition and can give feedback giving a window with the subject's info from database and sending an e-mail notification to interested institutions using android application.

Keywords: face detection, face recognition, eigen faces, algorithm

Procedia PDF Downloads 332