Search results for: scanning path

Authors: Sibani Bisoyi, Ute Zschieschang, Alexander Hoyer, Hagen Klauk

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Abstract— Organic thin-film transistors (TFTs) have great potential to be used for various applications such as flexible displays or sensors. For some of these applications, the TFTs must be able to withstand temperatures in excess of 100 °C, for example to permit the integration with devices or components that require high process temperatures, or to make it possible that the devices can be subjected to the standard sterilization protocols required for biomedical applications. In this work, we have investigated how the thermal stability of low-voltage small-molecule semiconductor dinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (DNTT) TFTs is affected by the encapsulation of the TFTs and by the ambient in which the thermal stress is performed. We also studied to which extent the thermal stability of the TFTs depends on the channel length. Some of the TFTs were encapsulated with a layer of vacuum-deposited Teflon, while others were left without encapsulation, and the thermal stress was performed either in nitrogen or in air. We found that the encapsulation with Teflon has virtually no effect on the thermal stability of our TFTs. In contrast, the ambient in which the thermal stress is conducted was found to have a measurable effect, but in a surprising way: When the thermal stress is carried out in nitrogen, the mobility drops to 70% of its initial value at a temperature of 160 °C and to close to zero at 170 °C, whereas when the stress is performed in air, the mobility remains at 75% of its initial value up to a temperature of 160 °C and at 60% up to 180 °C. To understand this behavior, we studied the effect of the thermal stress on the semiconductor thin-film morphology by scanning electron microscopy. While the DNTT films remain continuous and conducting when the heating is carried out in air, the semiconductor morphology undergoes a dramatic change, including the formation of large, thick crystals of DNTT and a complete loss of percolation, when the heating is conducted in nitrogen. We also found that when the TFTs are heated to a temperature of 200 °C in air, all TFTs with a channel length greater than 50 µm are destroyed, while TFTs with a channel length of less than 50 µm survive, whereas when the TFTs are heated to the same temperature (200 °C) in nitrogen, only the TFTs with a channel smaller than 8 µm survive. This result is also linked to the thermally induced changes in the semiconductor morphology.

Keywords: organic thin-film transistors, encapsulation, thermal stability, thin-film morphology

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Authors: M. Jerold, V. Sivasubramanian, A. George, B.S. Ashik, S. S. Kumar

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Bioethanol is a sustainable biofuel that can be used alternative to fossil fuels. Today, third generation (3G) biofuel is gaining more attention than first and second-generation biofuel. The more lignin content in the lignocellulosic biomass is the major drawback of second generation biofuels. Algae are the renewable feedstock used in the third generation biofuel production. Algae contain a large number of carbohydrates, therefore it can be used for the fermentation by hydrolysis process. There are two groups of Algae, such as micro and macroalgae. In the present investigation, Macroalgae was chosen as raw material for the production of bioethanol. Two marine algae viz. Ulva Lactuca and Sargassum swartzii were used for the experimental studies. The algal biomass was characterized using various analytical techniques like Elemental Analysis, Scanning Electron Microscopy Analysis and Fourier Transform Infrared Spectroscopy to understand the physio-Chemical characteristics. The batch experiment was done to study the hydrolysis and operation parameters such as pH, agitation, fermentation time, inoculum size. The saccharification was done with acid and alkali treatment. The experimental results showed that NaOH treatment was shown to enhance the bioethanol. From the hydrolysis study, it was found that 0.5 M Alkali treatment would serve as optimum concentration for the saccharification of polysaccharide sugar to monomeric sugar. The maximum yield of bioethanol was attained at a fermentation time of 9 days. The inoculum volume of 1mL was found to be lowest for the ethanol fermentation. The agitation studies show that the fermentation was higher during the process. The percentage yield of bioethanol was found to be 22.752% and 14.23 %. The elemental analysis showed that S. swartzii contains a higher carbon source. The results confirmed hydrolysis was not completed to recover the sugar from biomass. The specific gravity of ethanol was found to 0.8047 and 0.808 for Ulva Lactuca and Sargassum swartzii, respectively. The purity of bioethanol also studied and found to be 92.55 %. Therefore, marine algae can be used as a most promising renewable feedstock for the production of bioethanol.

Keywords: algae, biomass, bioethaol, biofuel, pretreatment

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Authors: Thomas Louis, Irina Primac, Florent Morfoisse, Tania Durre, Silvia Blacher, Agnes Noel

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In vitro and in vivo lymphangiogenesis assays are essential for the identification of potential lymphangiogenic agents and the screening of pharmacological inhibitors. In the present study, we analyse three biological models: in vitro lymphatic endothelial cell spheroids, in vivo ear sponge assay, and in vivo lymph node colonisation by tumour cells. These assays provide suitable 3D models to test pro- and anti-lymphangiogenic factors or drugs. 3D images were acquired by confocal laser scanning and light sheet fluorescence microscopy. Virtual scan microscopy followed by 3D reconstruction by image aligning methods was also used to obtain 3D images of whole large sponge and ganglion samples. 3D reconstruction, image segmentation, skeletonisation, and other image processing algorithms are described. Fixed and time-lapse imaging techniques are used to analyse lymphatic endothelial cell spheroids behaviour. The study of cell spatial distribution in spheroid models enables to detect interactions between cells and to identify invasion hierarchy and guidance patterns. Global measurements such as volume, length, and density of lymphatic vessels are measured in both in vivo models. Branching density and tortuosity evaluation are also proposed to determine structure complexity. Those properties combined with vessel spatial distribution are evaluated in order to determine lymphangiogenesis extent. Lymphatic endothelial cell invasion and lymphangiogenesis were evaluated under various experimental conditions. The comparison of these conditions enables to identify lymphangiogenic agents and to better comprehend their roles in the lymphangiogenesis process. The proposed methodology is validated by its application on the three presented models.

Keywords: 3D image segmentation, 3D image skeletonisation, cell invasion, confocal microscopy, ear sponges, light sheet microscopy, lymph nodes, lymphangiogenesis, spheroids

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Authors: M. Kumpugdee-Vollrath, M. Tabatabaeifar, M. Helmis

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Shellac is a natural polyester resin secreted by insects. Pectins are natural, non-toxic and water-soluble polysaccharides extracted from the peels of citrus fruits or the leftovers of apples. Both polymers are allowed for the use in the pharmaceutical industry and as a food additive. SSB Aquagold® is the aqueous solution of shellac and can be used for a coating process as an enteric or controlled drug release polymer. In this study, tablets containing 10 mg methylene blue as a model drug were prepared with a rotary press. Those tablets were coated with mixtures of shellac and one of the pectin different types (i.e. CU 201, CU 501, CU 701 and CU 020) mostly in a 2:1 ratio or with pure shellac in a small scale fluidized bed apparatus. A stable, simple and reproducible three-stage coating process was successfully developed. The drug contents of the coated tablets were determined using UV-VIS spectrophotometer. The characterization of the surface and the film thickness were performed with the scanning electron microscopy (SEM) and the light microscopy. Release studies were performed in a dissolution apparatus with a basket. Most of the formulations were enteric coated. The dissolution profiles showed a delayed or sustained release with a lagtime of at least 4 h. Dissolution profiles of coated tablets with pure shellac had a very long lagtime ranging from 13 to 17.5 h and the slopes were quite high. The duration of the lagtime and the slope of the dissolution profiles could be adjusted by adding the proper type of pectin to the shellac formulation and by variation of the coating amount. In order to apply a coating formulation as a colon delivery system, the prepared film should be resistant against gastric fluid for at least 2 h and against intestinal fluid for 4-6 h. The required delay time was gained with most of the shellac-pectin polymer mixtures. The release profiles were fitted with the modified model of the Korsmeyer-Peppas equation and the Hixson-Crowell model. A correlation coefficient (R²) > 0.99 was obtained by Korsmeyer-Peppas equation.

Keywords: shellac, pectin, coating, fluidized bed, release, colon delivery system, kinetic, SEM, methylene blue

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Authors: Burdin Louise, Brulez Anne-Catherine, Mazurcyk Radoslaw, Leclercq Jean-louis, Benayoun Stéphane

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By using a biomimetic approach, an investigation was conducted to determine the connections between morphology and wetting. The interest is focused on the Morpho peleides butterfly. This butterfly is already well-known among researchers for its brilliant iridescent color and has inspired numerous innovations. The intricate structure of its wings is responsible for such color. However, this multiscale structure exhibits a multitude of other features, such as hydrophobicity. Given the limited research on the wetting properties of Morpho butterfly, a detailed analysis of its wetting behavior is proposed. Multiscale surface topographies of the Morpho peleides butterfly were analyzed using scanning electron microscope and atomic force microscopy. To understand the relationship between morphology and wettability, a goniometer was employed to measured static and dynamic contact angle. Since several studies have consistently demonstrated that superhydrophobic surfaces can effectively delay freezing, icing delay time the Morpho’s wings was also measured. The results revealed contact angles close to 136°, indicating a high degree of hydrophobicity. Moreover, sliding angles (SA) were measured in different directions, including along and against the rolling-outward direction. The findings suggest anisotropic wetting. Specifically, when the wing was tilted along the rolling outward direction (i.e., away from the insect’s body) SA was about 7°. While, when the wing was tilted against the rolling outward direction, SA was about 29°. This phenomenon is directly linked to the butterfly’s survival strategy. To investigate the exclusive morphological impact on anti-icing properties, PDMS replicas of the Morpho butterfly were obtained. When compared to flat PDMS and microscale textured PDMS, Morpho replications exhibited a longer freezing time. Therefore, this could be a source of inspiration for designing superhydrophobic surfaces with anti-icing applications or functional surfaces with controlled wettability.

Keywords: biomimetic, anisotropic wetting, anti-icing, multiscale roughness

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Authors: Elias L. Souza, Noeli Sellin, Cintia Marangoni, Ozair Souza

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Among the different forms of reuse and recovery of agro-residual waste is the production of biofuels. The production of second-generation ethanol has been evaluated and proposed as one of the technically viable alternatives for this purpose. This research work employed the banana pseudostem as biomass. Two different chemical pre-treatment methods (acid hydrolisis with H2SO4 2% w/w and alkaline hydrolysis with NaOH 3% w/w) of dry and milled biomass (70 g/L of dry matter, ms) were assessed, and the corresponding reducing sugars yield, AR, (YAR), after enzymatic saccharification, were determined. The effect on YAR by increasing the dry matter (ms) from 70 to 100 g/L, in dry and milled biomass and also fresh, were analyzed. Changes in cellulose crystallinity and in biomass surface morphology due to the different chemical pre-treatments were analyzed by X-ray diffraction and scanning electron microscopy. The acid pre-treatment resulted in higher YAR values, whether related to the cellulose content under saccharification (RAR = 79,48) or to the biomass concentration employed (YAR/ms = 32,8%). In a comparison between alkaline and acid pre-treatments, the latter led to an increase in the cellulose content of the reaction mixture from 52,8 to 59,8%; also, to a reduction of the cellulose crystallinity index from 51,19 to 33,34% and increases in RAR (43,1%) and YAR/ms (39,5%). The increase of dry matter (ms) bran from 70 to 100 g/L in the acid pre-treatment, resulted in a decrease of average yields in RAR (43,1%) and YAR/ms (18,2%). Using the pseudostem fresh with broth removed, whether for 70 g/L concentration or 100 g/L in dry matter (ms), similarly to the alkaline pre-treatment, has led to lower average values in RAR (67,2% and 42,2%) and in YAR/ms (28,4% e 17,8%), respectively. The acid pre-treated and saccharificated biomass broth was detoxificated with different activated carbon contents (1,2 and 4% w/v), concentrated up to AR = 100 g/L and fermented by Saccharomyces cerevisiae. The yield values (YP/AR) and productivity (QP) in ethanol were determined and compared to those values obtained from the fermentation of non-concentrated/non-detoxificated broth (AR = 18 g/L) and concentrated/non-detoxificated broth (AR = 100 g/L). The highest average value for YP/AR (0,46 g/g) was obtained from the fermentation of non-concentrated broth. This value did not present a significant difference (p<0,05) when compared to the YP/RS related to the broth concentrated and detoxificated by activated carbon 1% w/v (YP/AR = 0,41 g/g). However, a higher ethanol productivity (QP = 1,44 g/L.h) was achieved through broth detoxification. This value was 75% higher than the average QP determined using concentrated and non-detoxificated broth (QP = 0,82 g/L.h), and 22% higher than the QP found in the non-concentrated broth (QP = 1,18 g/L.h).

Keywords: biofuels, biomass, saccharification, bioethanol

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Authors: Maria Altamirano, Alfonso Duran

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Biostimulation has recently become important in order to improve the stability and performance of the anaerobic digestion (AD) process. This strategy involves the addition of nutrients or supplements to improve the rate of degradation of a native microbial consortium. With the aim of biostimulate sytrophism between secondary fermenting bacteria and methanogenic archaea, improving metabolite degradation and efficient conversion to methane, the addition of conductive materials, mainly carbon based have been studied. This research seeks to highlight the effect that coconut biochar (CBC) has on the metanogenic conversion of the organic fraction of municipal solid waste (OFMSW), analyzing the surface chemistry properties that give biochar its capacity to serve as a redox mediator in the anaerobic digestion process. The biochar characterization techniques were electrical conductivity (EC) scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier Transform Infrared Transmission Spectroscopy (FTIR) and Cyclic Voltammetry (CV). Effect of coconut biochar addition was studied using Authomatic Methane Potential Test System (AMPTS II) applying a one-way variance analysis to determine the dose that leads to higher methane performance. The surface chemistry of the CBC could confer properties that enhance the AD process, such as the presence of alkaline and alkaline earth metals and their hydrophobicity that may be related to their buffering capacity and the adsorption of polar and non-polar compounds, such as NH4+ and CO2. It also has aromatic functional groups, just as quinones, whose potential as a redox mediator has been demonstrated and its morphology allows it to form an immobilizing matrix that favors a closer activity among the syntrophic microorganisms, which directly contributed in the oxidation of secondary metabolites and the final reduction to methane, whose yield is increased by 39% compared to controls, with a CBC dose of 1 g/L.

Keywords: anaerobic digestion, biochar, biostimulation, syntrophic metabolism

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Authors: Rohollah Ghasemi, Arvin Ghorbani

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This study investigates the effect of austempering temperature on microstructure and scratch behavior of the austempered heat-treated compacted graphite irons. The as-cast was used as base material for heat treatment practices. The samples were extracted from as-cast ferritic CGI pieces and were heat treated under austenitising temperature of 900°C for 60 minutes which followed by quenching in salt-bath at different austempering temperatures of 275°C, 325°C and 375°C. For all heat treatments, an austempering holding time of 30 minutes was selected for this study. Light optical microscope (LOM) and scanning electron microscope (SEM) and electron back scattered diffraction (EBSD) analysis confirmed the ausferritic matrix formed in all heat-treated samples. Microscratches were performed under the load of 200, 600 and 1000 mN using a sphero-conical diamond indenter with a tip radius of 50 μm and induced cone angle 90° at a speed of 10 μm/s at room temperature ~25°C. An instrumented nanoindentation machine was used for performing nanoindentation hardness measurement and microscratch testing. Hardness measurements and scratch resistance showed a significant increase in Brinell, Vickers, and nanoindentation hardness values as well as microscratch resistance of the heat-treated samples compared to the as-cast ferritic sample. The increase in hardness and improvement in microscratch resistance are associated with the formation of the ausferrite matrix consisted of carbon-saturated retained austenite and acicular ferrite in austempered matrix. The maximum hardness was observed for samples austempered at 275°C which resulted in the formation of very fine acicular ferrite. In addition, nanohardness values showed a quite significant variation in the matrix due to the presence of acicular ferrite and carbon-saturated retained austenite. It was also observed that the increase of austempering temperature resulted in increase of volume of the carbon-saturated retained austenite and decrease of hardness values.

Keywords: austempered CGI, austempering, scratch testing, scratch plastic deformation, scratch hardness

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Authors: Yogeeta O. Agrawal, Hitendra S. Mahajan, Sanjay J. Surana

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Methotrexate is effective in controlling recalcitrant psoriasis when administered by the oral or parenteral route long-term. However, the systematic use of this drug may provoke any of a number of side effects, notably hepatotoxic effects. To reduce these effects, clinical studies have been done with topical MTx. It is useful in treating a number of cutaneous conditions, including psoriasis. A major problem in topical administration of MTx currently available in market is that the drug is hydrosoluble and is mostly in the dissociated form at physiological pH. Its capacity for passive diffusion is thus limited. Localization of MTx in effected layers of skin is likely to improve the role of topical dosage form of the drug as a supplementary to oral therapy for treatment of psoriasis. One of the possibilities for increasing the penetration of drugs through the skin is the use of Nanostructured lipid Carriers. The objective of the present study was to formulate and characterize Methotrexate loaded Nanostructured Lipid Carriers (MtxNLCs), to understand in vitro drug release and evaluate the role of the developed gel in the topical treatment of psoriasis. MtxNLCs were prepared by solvent diffusion technique using 3(2) full factorial design.The mean diameter and surface morphology of MtxNLC was evaluated. MtxNLCs were lyophilized and crystallinity of NLC was characterized by Differential Scanning Calorimtery (DSC) and powder X-Ray Diffraction (XRD). The NLCs were incorporated in 1% w/w Carbopol 934 P gel base and in vitro skin deposition studies in Human Cadaver Skin were conducted. The optimized MtxNLCs were spherical in shape, with average particle size of 253(±9.92)nm, zeta potential of -30.4 (±0.86) mV and EE of 53.12(±1.54)%. DSC and XRD data confirmed the formation of NLCs. Significantly higher deposition of Methotrexate was found in human cadaver skin from MtxNLC gel (71.52 ±1.23%) as compared to Mtx plain gel (54.28±1.02%). Findings of the studies suggest that there is significant improvement in therapeutic index in treatment of psoriasis by MTx-NLCs incorporated gel base developed in this investigation over plain drug gel currently available in the market.

Keywords: methotrexate, psoriasis, NLCs, hepatotoxic effects

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Authors: Rehan Ullah

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The primary purpose of the study is to observe the relationship that exists between the organizational information technology (IT) capabilities and the organizational performance in China and Pakistan. Nations like China and Pakistan utilize modern techno-how to enhance their production endeavors. Therefore, making a wide-ranging comparison of the manufacturing services between China and Pakistan was chosen due to numerous reasons. One reason for carrying out this comparison is to determine how IT of the two countries enhances organizational competency on small and medium-sized manufacturing enterprises (SMEs). The study hypothesized that organizational IT capabilities (IT infrastructure, IT competence) have a positive influence on organizational performance and the strategic benefits of IT have a mediating effect on the relationship between IT capability and organizational performance. To investigate the relationship between IT capabilities and organizational performance, surveys were sent to managers of small, medium-sized manufacturing organizations located in the southwestern region, Sichuan province of China, and Pakistani companies, which are located in Islamabad, Lahore, and Karachi. These cities were selected as typical representatives of each country. Organizational performance has been measured in terms of profitability, organizational success, growth, market share, and innovativeness. Out of 400 surveys distributed to different manufacturing organizations, 303 usable and valid responses were received that are analyzed in this research. The data were examined using SPSS and Smart PLS computer software. The results of the study, including the descriptive statistics of each variable, are used. The outer model has been measured with considerations to content validity, discriminant validity, and convergent validity. The path coefficients among the constructs were also computed when analyzing the structural model using the bootstrapping technique. The analysis of data from both China and Pakistan yields an identical but unique result. The results show that IT infrastructure, IT competence, strategic benefits of IT are all correlated to the performance of the organizations. Moreover, strategic benefits of IT have been proved to mediate the relationship between IT capabilities and organization performance. The author, concerning the role of IT on the performance of an organization, highlights the different aspects as well as its benefits in an organization. The overall study concludes several implications for both managers and academicians. It also provides the limitations of the study and offers recommendations for future studies and practice.

Keywords: organizational performance, IT capabilities, IT infrastructure, IT competence, strategic benefits of IT, China, Pakistan

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Authors: Abdul Matin, Muhammad Ajmal, Uzma Yunus, Noaman-ul Haq, Hafiz M. Shohaib, Ambreen G. Muazzam

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Carbon nanoparticles (CNPs) have unique properties that are useful for the diagnosis and treatment of cancer due to their precise properties like small size (ideal for delivery within the body) stability in solvent and tunable surface chemistry for targeted delivery. Here, highly fluorescent, monodispersed and water-soluble CNPs were synthesized directly from a suitable carbohydrate source (glucose and sucrose) by one-step acid assisted ultrasonic treatment at 35 KHz for 4 hours. This method is green, simple, rapid and economical and can be used for large scale production and applications. The average particle sizes of CNPs are less than 10nm and they emit bright and colorful green-blue fluorescence under the irradiation of UV-light at 365nm. The CNPs were characterized by scanning electron microscopy, fluorescent spectrophotometry, Fourier transform infrared spectrophotometry, ultraviolet-visible spectrophotometry and TGA analysis. Fluorescent CNPs were used as fluorescent probe and nano-carriers for anticancer drug. Functionalized CNPs (with ethylene diamine) were attached with anticancer drug-Methotrexate. In vitro bioactivity and biocompatibility of CNPs-drug conjugates was evaluated by LDH assay and Sulforhodamine B assay using human lung carcinoma cell lines (H157). Our results reveled that CNPs showed biocompatibility and CNPs-anticancer drug conjugates have shown potent cytotoxic effects and high antitumor activities in lung cancer cell lines. CNPs are proved to be excellent substitute for conventional drug delivery cargo systems and anticancer therapeutics in vitro. Our future studies will be more focused on using the same nanoparticles in vivo model system.

Keywords: carbon nanoparticles, carbon nanoparticles-methotrexate conjugates, human lung carcinoma cell lines, lactate dehydrogenase, methotrexate

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Authors: Ni Zhenyu

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A human settlement is defined as the social activities, social relationships and lifestyles generated within a certain territory, which is also relatively independent territorial living space and domain composed of common people. Along with the advancement of technology and the development of society, the idea, presented in traditional research, that human settlements are deemed as substantial organic integrity with strong autonomy, are more often challenged nowadays. Spatial form of human settlements is one of the most outstanding external expressions with its subjectivity and autonomy, nevertheless, the projections of social, economic activities on certain territories are even more significant. What exactly is the relationship between human beings and the spatial form of the settlements where they live in? a question worth thinking over has been raised, that if a new view, a spatial anthropological one , can be constructed to review and respond to spatial form of human settlements based on research theories and methods of cultural anthropology within the profession of architecture. This article interprets how the typical spatial form of human settlements in the basin area of Bac Giang Province is formed under the collective impacts of local social order, land use condition, topographic features, and social contracts. A particular case of the settlement in Sizhai Village, City of Zhuji, Zhejiang Province is chosen to study for research purpose. Spatial form of human settlements are interpreted as a modeled integrity affected corporately by dominant economy, social patterns, key symbol marks and core values, etc.. Spatial form of human settlements, being a structured existence, is a materialized, behavioral, and social space; it can be considered as a place where human beings realize their behaviors and a path on which the continuity of their behaviors are kept, also for social practice a territory where currant social structure and social relationships are maintained, strengthened and rebuilt. This article aims to break the boundary of understanding that spatial form of human settlements is pure physical space, furthermore, endeavors to highlight the autonomy status of human beings, focusing on their relationships with certain territories, their interpersonal relationships, man-earth relationships and the state of existence of human beings, elaborating the deeper connotation behind spatial form of human settlements.

Keywords: spatial anthropology, human settlement, spatial pattern, spatial structure

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Authors: Yasser Sanad, Thu Trang Dao

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Introduction: Implementing the One Health (OH) approach requires an integrated, interdisciplinary, and cross-sectoral methodology. OH is a key tool for developing and implementing programs and projects and includes developing ambitious policies that consider the common needs and benefits of human, animal, plant, and ecosystem health. OH helps humanity readjust its path to environmentally friendly and impartial sustainability. As co-leader of the Global Health Security Agenda’s Zoonotic Disease Action Package, Vietnam pioneered a strong OH approach to effectively address early waves of the COVID-19 outbreak in-country. Context and Aim: The repeated surges in COVID-19 in Vietnam challenged the capabilities of the national system and disclosed the gaps in multi-sectoral coordination and resilience. To address this, FHI 360 advocated for the standardization of the OH platform by government actors to increase the resiliency of the system during and post COVID-19. Methods: FHI 360 coordinated technical resources to develop and implement evidence-based OH policies, promoting high-level policy dialogue between the Ministries of Health, Agriculture, and the Environment, and policy research to inform developed policies and frameworks. Through discussions, an OH-building Partnership (OHP) was formed, linking climate change, the environment, and human and animal health. Findings: The OHP Framework created a favorable policy environment within and between sectors, as well as between governments and international health security partners. It also promoted strategic dialogue, resource mobilization, policy advocacy, and integration of international systems with National Steering Committees to ensure accountability and emphasize national ownership. Innovative contribution to policy, practice and/or research: OHP was an effective evidence-based research-to-policy platform linking to the National One Health Strategic Plan (2021-2025). Collectively they serve as a national framework for the implementation and monitoring of OH activities. Through the adoption of policies and plans, the risk of zoonotic pathogens, environmental agent spillover, and antimicrobial resistance can be minimized through strengthening multi-sectoral OH collaboration for health security.

Keywords: one health, national policies, health security, COVID-19, Vietnam

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Authors: Naima Bouslah, Leila Bounabi, Farid Ouazib, Nabila Haddadine

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Conventional release dosage forms are known to provide an immediate release of the drug. Controlling the rate of drug release from polymeric matrices is very important for a number of applications, particularly in the pharmaceutical area. Hydrogels are polymers in three-dimensional network arrangement, which can absorb and retain large amounts of water without dissolution. They have been frequently used to develop controlled released formulations for oral administration because they can extend the duration of drug release and thus reduce dose to be administrated improving patient compliance. Tramadol is an opioid pain medication used to treat moderate to moderately severe pain. When taken as an immediate-release oral formulation, the onset of pain relief usually occurs within about an hour. In the present work, we synthesized pH-responsive hydrogels of (hydroxyl ethyl methacrylate-co-acrylic acid), (HEMA-AA) for control drug delivery of tramadol in the gastro-intestinal tractus. The hydrogels with different acrylic acid content, were synthesized by free radical polymerization and characterized by FTIR spectroscopy, X ray diffraction analysis (XRD), differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA). FTIR spectroscopy has shown specific hydrogen bonding interactions between the carbonyl groups of the hydrogels and hydroxyl groups of tramadol. Both the XRD and DSC studies revealed that the introduction of tramadol in the hydrogel network induced the amorphization of the drug. The swelling behaviour, absorptive kinetics and the release kinetics of tramadol in simulated gastric fluid (pH 1.2) and in simulated intestinal fluid (pH 7.4) were also investigated. The hydrogels exhibited pH-responsive behavior in the swelling study. The (HEMA-AA) hydrogel swelling was much higher in pH =7.4 medium. The tramadol release was significantly increased when pH of the medium was changed from simulated gastric fluid (pH 1.2) to simulated intestinal fluid (pH 7.4). Using suitable mathematical models, the apparent diffusional coefficients and the corresponding kinetic parameters have been calculated.

Keywords: biopolymres, drug delivery, hydrogels, tramadol

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Authors: Krasimira N. Zhilkova, Mariya K. Kyulavska, Roza P. Mateva

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The anionic polymerization of -caprolactam (CL) with bifunctional activators has been extensively studied as an effective and beneficial method of improving chemical and impact resistances, elasticity and other mechanical properties of polyamide (PA6). In presence of activators or macroactivators (MAs) also called polymeric activators (PACs) the anionic polymerization of lactams proceeds rapidly at a temperature range of 130-180C, well below the melting point of PA-6 (220C) permitting thus the direct manufacturing of copolymer product together with desired modifications of polyamide properties. Copolymers of PA6 with an elastic polypropylene glycol (PPG) middle block into main chain were successfully synthesized via activated anionic ring opening polymerization (ROP) of CL. Using novel PACs based on PPG polyols (with differ molecular weight) the anionic ROP of CL was realized and investigated in the presence of a basic initiator sodium salt of CL (NaCL). The PACs were synthesized as N-carbamoyllactam derivatives of hydroxyl terminated PPG functionalized with isophorone diisocyanate [IPh, 5-Isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane] and blocked then with CL units via an addition reaction. The block copolymers were analyzed and proved with 1H-NMR and FT-IR spectroscopy. The influence of the CL/PACs ratio in feed, the length of the PPG segments and polymerization conditions on the kinetics of anionic ROP, on average molecular weight, and on the structure of the obtained block copolymers were investigated. The structure and phase behaviour of the copolymers were explored with differential scanning calorimetry, wide-angle X-ray diffraction, thermogravimetric analysis and dynamic mechanical thermal analysis. The crystallinity dependence of PPG content incorporated into copolymers main backbone was estimate. Additionally, the mechanical properties of the obtained copolymers were studied by notched impact test. From the performed investigation in this study could be concluded that using PPG based PACs at the chosen ROP conditions leads to obtaining well-defined PA6-b-PPG-b-PA6 copolymers with improved impact resistance.

Keywords: anionic ring opening polymerization, caprolactam, polyamide copolymers, polypropylene glycol

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Authors: Mohanapriya Subramanian, V. Raj

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Direct methanol fuel cells (DMFCs) are considered to be one of the most promising candidates for portable and stationary applications in the view of their advantages such as high energy density, easy manipulation, high efficiency and they operate with liquid fuel which could be used without requiring any fuel-processing units. Electrolyte membrane of DMFC plays a key role as a proton conductor as well as a separator between electrodes. Increasing concern over environmental protection, biopolymers gain tremendous interest owing to their eco-friendly bio-degradable nature. Pectin is a natural anionic polysaccharide which plays an essential part in regulating mechanical behavior of plant cell wall and it is extracted from outer cells of most of the plants. The aim of this study is to develop and demonstrate pectin based polymer composite membranes as methanol impermeable polymer electrolyte membranes for DMFCs. Pectin based nanocomposites membranes are prepared by solution-casting technique wherein pectin is blended with chitosan followed by the addition of optimal amount of sulphonic acid modified Titanium dioxide nanoparticle (S-TiO2). Nanocomposite membranes are characterized by Fourier Transform-Infra Red spectroscopy, Scanning electron microscopy, and Energy dispersive spectroscopy analyses. Proton conductivity and methanol permeability are determined into order to evaluate their suitability for DMFC application. Pectin-chitosan blends endow with a flexible polymeric network which is appropriate to disperse rigid S-TiO2 nanoparticles. Resulting nanocomposite membranes possess adequate thermo-mechanical stabilities as well as high charge-density per unit volume. Pectin-chitosan natural polymeric nanocomposite comprising optimal S-TiO2 exhibits good electrochemical selectivity and therefore desirable for DMFC application.

Keywords: biopolymers, fuel cells, nanocomposite, methanol crossover

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Authors: Noura El-Ahmady El-Naggar

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Among the antitumour drugs, bacterial enzyme L-asparaginase has been employed as the most effective chemotherapeutic agent in pediatric oncotherapy especially for acute lymphoblastic leukemia. Glutaminase free L-asparaginase producing actinomycetes were isolated from soil samples collected from Egypt. Among them, a potential culture, strain NEAE-119, was selected and identified on the basis of morphological, cultural, physiological and biochemical properties, together with 16S rDNA sequence as Streptomyces olivaceus NEAE-119 and sequencing product(1509 bp) was deposited in the GenBank database under accession number KJ200342. The optimization of different process parameters for L-asparaginase production by Streptomyces olivaceus NEAE-119 using Plackett–Burman experimental design and response surface methodology was carried out. Fifteen nutritional variables (temperature, pH, incubation time, inoculum size, inoculum age, agitation speed, dextrose, starch, L-asparagine, KNO3, yeast extract, K2HPO4, MgSO4.7H2O, NaCl and FeSO4. 7H2O) were screened using Plackett–Burman experimental design. The most positive significant independent variables affecting enzyme production (temperature, inoculum age and agitation speed) were further optimized by the central composite face-centered design -response surface methodology. As a result, a medium of the following formula is the optimum for producing an extracellular L-asparaginase in the culture filtrate of Streptomyces olivaceus NEAE-119: Dextrose 3g, starch 20g, L-asparagine 10g, KNO3 1g, K2HPO4 1g, MgSO4.7H2O 0.1g, NaCl 0.1g, pH 7, temperature 37°C, agitation speed 200 rpm/min, inoculum size 4%, v/v, inoculum age 72 h and fermentation period 5 days.

Keywords: Streptomyces olivaceus NEAE-119, glutaminase free L-asparaginase, production, Plackett-Burman design, central composite face-centered design, 16S rRNA, scanning electron microscope

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Authors: Besma Khalfoun

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In many current Human Activity Recognition (HAR) applications, users' data is frequently shared and centrally stored by third parties, posing a significant privacy risk. This practice makes these entities attractive targets for extracting sensitive information about users, including their identity, health status, and location, thereby directly violating users' privacy. To tackle the issue of centralized data storage, a relatively recent paradigm known as federated learning has emerged. In this approach, users' raw data remains on their smartphones, where they train the HAR model locally. However, users still share updates of their local models originating from raw data. These updates are vulnerable to several attacks designed to extract sensitive information, such as determining whether a data sample is used in the training process, recovering the training data with inversion attacks, or inferring a specific attribute or property from the training data. In this paper, we first introduce PUR-Attack, a parameter-based user re-identification attack developed for HAR applications within a federated learning setting. It involves associating anonymous model updates (i.e., local models' weights or parameters) with the originating user's identity using background knowledge. PUR-Attack relies on a simple yet effective machine learning classifier and produces promising results. Specifically, we have found that by considering the weights of a given layer in a HAR model, we can uniquely re-identify users with an attack success rate of almost 100%. This result holds when considering a small attack training set and various data splitting strategies in the HAR model training. Thus, it is crucial to investigate protection methods to mitigate this privacy threat. Along this path, we propose SAFER, a privacy-preserving mechanism based on adaptive local differential privacy. Before sharing the model updates with the FL server, SAFER adds the optimal noise based on the re-identification risk assessment. Our approach can achieve a promising tradeoff between privacy, in terms of reducing re-identification risk, and utility, in terms of maintaining acceptable accuracy for the HAR model.

Keywords: federated learning, privacy risk assessment, re-identification risk, privacy preserving mechanisms, local differential privacy, human activity recognition

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Authors: Chanchal Biswas, Anrin Bhattacharyya, Gopes Chandra Das, Mahua Ghosh Chaudhuri, Rajib Dey

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Boiler coals with low fixed carbon and higher ash content have always challenged the metallurgists to develop a suitable method for their utilization. In the present study, an attempt is made to establish an energy effective method for the reduction of iron ore fines in the form of nuggets by using ‘Syngas’. By devolatisation (expulsion of volatile matter by applying heat) of boiler coal, gaseous product (enriched with reducing agents like CO, CO2, H2, and CH4 gases) is generated. Iron ore nuggets are reduced by this syngas. For that reason, there is no direct contact between iron ore nuggets and coal ash. It helps to control the minimization of the sulphur intake of the reduced nuggets. A laboratory scale devolatisation furnace designed with reduction facility is evaluated after in-depth studies and exhaustive experimentations including thermo-gravimetric (TG-DTA) analysis to find out the volatile fraction present in boiler grade coal, gas chromatography (GC) to find out syngas composition in different temperature and furnace temperature gradient measurements to minimize the furnace cost by applying one heating coil. The nuggets are reduced in the devolatisation furnace at three different temperatures and three different times. The pre-reduced nuggets are subjected to analytical weight loss calculations to evaluate the extent of reduction. The phase and surface morphology analysis of pre-reduced samples are characterized using X-ray diffractometry (XRD), energy dispersive x-ray spectrometry (EDX), scanning electron microscopy (SEM), carbon sulphur analyzer and chemical analysis method. Degree of metallization of the reduced nuggets is 78.9% by using boiler grade coal. The pre-reduced nuggets with lesser sulphur content could be used in the blast furnace as raw materials or coolant which would reduce the high quality of coke rate of the furnace due to its pre-reduced character. These can be used in Basic Oxygen Furnace (BOF) as coolant also.

Keywords: alternative ironmaking, coal gasification, extent of reduction, nugget making, syngas based DRI, solid state reduction

Procedia PDF Downloads 259

Authors: T. Abbas, J. McEvoy, E. Khan

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Pesticide contamination in water supply is a common environmental problem in rural agricultural communities. Advanced water treatment processes such as membrane filtration and adsorption on activated carbon only remove pesticides from water without degrading them into less toxic/easily degradable compounds leaving behind contaminated brine and activated carbon that need to be managed. Rural communities which normally cannot afford expensive water treatment technologies need an economical and sustainable filter which not only treats pesticides from water but also degrades them into benign products. In this study, iron turning waste experimented as potential point-of-use filtration media for the removal/degradation of a mixture of six chlorinated pesticides (lindane, heptachlor, endosulfan, dieldrin, endrin, and DDT) in water. As a common and traditional medium for water filtration, sand was also tested along with iron turning waste. Iron turning waste was characterized using scanning electron microscopy and energy dispersive X-Ray analyzer. Four glass columns with different filter media layer configurations were set up: (1) only sand, (2) only iron turning, (3) sand and iron turning (two separate layers), and (4) sand, iron turning and sand (three separate layers). The initial pesticide concentration and flow rate were 2 μg/L and 10 mL/min. Results indicate that sand filtration was effective only for the removal of DDT (100%) and endosulfan (94-96%). Iron turning filtration column effectively removed endosulfan, endrin, and dieldrin (85-95%) whereas the lindane and DDT removal were 79-85% and 39-56%, respectively. The removal efficiencies for heptachlor, endosulfan, endrin, dieldrin, and DDT were 90-100% when sand and iron turning waste (two separate layers) were used. However, better removal efficiencies (93-100%) for five out of six pesticides were achieved, when sand, iron turning and sand (three separate layers) were used as filtration media. Moreover, the effects of water pH, amounts of media, and minerals present in water such as magnesium, sodium, calcium, and nitrate on the removal of pesticides were examined. Results demonstrate that iron turning waste efficiently removed all the pesticides under studied parameters. Also, it completely de-chlorinated all the pesticides studied and based on the detection of by-products, the degradation mechanisms for all six pesticides were proposed.

Keywords: pesticide contamination, rural communities, iron turning waste, filtration

Procedia PDF Downloads 255

Authors: Venkataraman Sivasankar, Kiyoshi Omine, Hideaki Sano

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The leaching of fluoride from Plaster Board Waste (PBW) is quite feasible in soil and water environments. The Ministry of Environment, Japan recommended the standard limit of 0.8 mgL⁻¹ or less for fluoride. Although the utilization of PBW as a substitute for cement is rather meritorious, its fluoride leaching behavior deteriorates the quality of soil and water and therefore envisaged as a demerit. In view of this fluoride leaching problem, the present research is focused on immobilizing fluoride in PBW. The immobilization experiments were conducted with four chemical systems operated by DAHP (diammonium hydrogen phosphate) and phosphoric acid carbonization of bamboo mass coupled with certain inorganic reactions using reagents such as calcium hydroxide, sodium hydroxide, and aqueous ammonia. The fluoride immobilization was determined after shaking the reactor contents including the plaster board waste for 24 h at 25˚C. In the DAHP system, the immobilization of fluoride was evident from the leaching of fluoride in the range 0.071-0.12 mgL⁻¹, 0.026-0.14 mgL⁻¹ and 0.068-0.12 mgL⁻¹ for the reaction temperatures at 30˚C, 50˚C, and 90˚C, respectively, with final pH of 6.8. The other chemical systems designated as PACCa, PACAm, and PACNa could immobilize fluoride in PBW, and the resulting solution was analyzed with the fluoride less than the Japanese environmental standard of 0.8 mgL⁻¹. In the case of PACAm and PACCa systems, the calcium concentration was found undetectable and witnessed the formation of phosphate compounds. The immobilization of fluoride was found inversely proportional to the increase in the volume of leaching solvent and dose of PBW. Characterization studies of PBW and the solid after fluoride immobilization was done using FTIR (Fourier transform infrared spectroscopy), Raman spectroscopy, FE-SEM ( Field Emission Scanning Electron Microscopy) with EDAX (Energy Dispersive Spectroscopy), XRD (X-ray diffraction), and XPS (X-ray photoelectron spectroscopy). The results revealed the formation of new calcium phosphate compounds such as apatite, monetite, and hydroxylapatite. The participation of such new compounds in fluoride immobilization seems indispensable through the exchange mechanism of hydroxyl and fluoride groups. Acknowledgment: First author thanks to Japanese Society for the Promotion of Science (JSPS) for the award of the fellowship (ID No. 16544).

Keywords: characterization, fluoride, immobilization, plaster board waste

Procedia PDF Downloads 157

Authors: Yi-Chun Kuo, Jo-Chieh Lin

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The objective of a supply chain strategy is to reduce waste and increase efficiency to attain cost benefits, and to guarantee supply chain flexibility when facing the ever-changing market environment in order to meet customer requirements. Strategy implementation aims to fulfill common goals and attain benefits by integrating upstream and downstream enterprises, sharing information, conducting common planning, and taking part in decision making, so as to enhance the overall performance of the supply chain. With the rise of outsourcing and globalization, the increasing dependence on suppliers and customers and the rapid development of information technology, the complexity and uncertainty of the supply chain have intensified, and supply chain vulnerability has surged, resulting in adverse effects on supply chain performance. Thus, this study aims to use supply chain vulnerability as a moderating variable and apply structural equation modeling (SEM) to determine the relationships among supply chain strategy, supply chain integration, and supply chain performance, as well as the moderating effect of supply chain vulnerability on supply chain performance. The data investigation of this study was questionnaires which were collected from the management level of enterprises in Taiwan and China, 149 questionnaires were received. The result of confirmatory factor analysis shows that the path coefficients of supply chain strategy on supply chain integration and supply chain performance are positive (0.497, t= 4.914; 0.748, t= 5.919), having a significantly positive effect. Supply chain integration is also significantly positively correlated to supply chain performance (0.192, t = 2.273). The moderating effects of supply chain vulnerability on supply chain strategy and supply chain integration to supply chain performance are significant (7.407; 4.687). In Taiwan, 97.73% of enterprises are small- and medium-sized enterprises (SMEs) focusing on receiving original equipment manufacturer (OEM) and original design manufacturer (ODM) orders. In order to meet the needs of customers and to respond to market changes, these enterprises especially focus on supply chain flexibility and their integration with the upstream and downstream enterprises. According to the observation of this research, the effect of supply chain vulnerability on supply chain performance is significant, and so enterprises need to attach great importance to the management of supply chain risk and conduct risk analysis on their suppliers in order to formulate response strategies when facing emergency situations. At the same time, risk management is incorporated into the supply chain so as to reduce the effect of supply chain vulnerability on the overall supply chain performance.

Keywords: supply chain integration, supply chain performance, supply chain vulnerability, structural equation modeling

Procedia PDF Downloads 315

Authors: Manisha Choudhary, Sudarsan Neogi

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Malachite green (MG), an organic basic dye, has been widely used for the dyeing purpose, as well as a fungicide and antiseptic in aquaculture industry to control fish parasites and disease. However, MG has now turned out to be an extremely controversial compound due to its adverse impact on living beings. Due to high toxicity, proper treatment of wastewater containing MG is utmost important. Among different available technologies, adsorption process is one of the most efficient and cost-effective treatment method due to its simplicity of design, ease of operation and regeneration of used materials. Nonetheless, commercial activated carbon is expensive leading the researchers to focus on utilizing natural resources. In the present work, a species of cactus, Opuntia ficus-indica (OFI), was used to develop a highly efficient, low-cost powdered activated carbon by chemical activation using NaOH. The biosorbent was characterized by Fourier-transform infrared spectroscopy, field emission scanning electron microscope, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller (BET) and X-ray diffraction analysis. Batch adsorption studies were performed to remove MG from an aqueous solution as a function of contact time, initial solution pH, initial dye concentration, biosorbent dosages, the presence of salt and temperature. By increasing the initial dye concentration from 100 to 500 mg/l, adsorption capacity increased from 165.45 to 831.58 mg/g. The adsorption kinetics followed the pseudo-second-order model and the chemisorption mechanisms were revealed. The electrostatic attractions and chemical interactions were observed between amino and hydroxyl groups of the biosorbent and amine groups of the dye. The adsorption was solely controlled by film diffusion. Different isotherm models were used to fit the adsorption data. The excellent recovery of adsorption efficiency after the regeneration of biosorbent indicated the high potential of this adsorbent to remove MG from aqueous solution and an excellent cost-effective biosorbent for wide application in wastewater treatment.

Keywords: adsorption, biosorbent, cactus, malachite green

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Authors: Nikhil Kumar, Asish Bandyopadhyay

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Laser welding process is a capable technology for forming the automobile, microelectronics, marine and aerospace parts etc. In the present work, a mathematical and statistical approach is adopted to study the laser welding of AISI 304 stainless steel. A robotic control 500 W pulsed Nd:YAG laser source with 1064 nm wavelength has been used for welding purpose. Butt joints are made. The effects of welding parameters, namely; laser power, scanning speed and pulse width on the seam width and depth of penetration has been investigated using the empirical models developed by response surface methodology (RSM). Weld quality is directly correlated with the weld geometry. Twenty sets of experiments have been conducted as per central composite design (CCD) design matrix. The second order mathematical model has been developed for predicting the desired responses. The results of ANOVA indicate that the laser power has the most significant effect on responses. Microstructural analysis as well as hardness of the selected weld specimens has been carried out to understand the metallurgical and mechanical behaviour of the weld. Average micro-hardness of the weld is observed to be higher than the base metal. Higher hardness of the weld is the resultant of grain refinement and δ-ferrite formation in the weld structure. The result suggests that the lower line energy generally produce fine grain structure and improved mechanical properties than the high line energy. The combined effects of input parameters on responses have been analyzed with the help of developed 3-D response surface and contour plots. Finally, multi-objective optimization has been conducted for producing weld joint with complete penetration, minimum seam width and acceptable welding profile. Confirmatory tests have been conducted at optimum parametric conditions to validate the applied optimization technique.

Keywords: ANOVA, laser welding, modeling and optimization, response surface methodology

Procedia PDF Downloads 294

Authors: Abidullah, Basharat Hussain, Jong Seok Kim

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Polymer electrolyte membrane fuel cell (PEMFC) is an electrochemical cell, which undergoes an oxygen reduction reaction to produce electrical energy. Platinum (Pt) metal has been used as a catalyst since its inception, but expensiveness is the major obstacle in the commercialization of fuel cells. Herein a non-precious group metal (NPGM) is employed instead of Pt to reduce the cost of PEMFCs. Manganese dioxide impregnated carbon nanotubes (MnO₂-CNTs composite) is a catalyst having excellent electrochemical properties and offers a better alternative to the Platinum-based PEMFC. The catalyst is synthesized by impregnating the transition metal on large surface carbonaceous CNTs by hydrothermal synthesis techniques. To enhance the catalytic activity and increase the volumetric current density, the sample was pyrolyzed at 800ᵒC under a nitrogen atmosphere. During pyrolysis, the nitrogen was doped in the framework of CNTs. Then the material was treated with acid for removing the unreacted metals and adding oxygen functional group to the CNT framework. This process ameliorates the catalytic activity of the manganese-based catalyst. The catalyst has been characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and the catalyst activity has been examined by rotating disc electrode (RDE) experiment. The catalyst was strong enough to withstand an austere alkaline environment in experimental conditions and had a high electrocatalytic activity for oxygen reduction reaction (ORR). Linear Sweep Voltammetry (LSV) depicts an excellent current density of -4.0 mA/cm² and an overpotential of -0.3V vs. standard calomel electrode (SCE) in 0.1M KOH electrolyte. Rotating disk electrode (RDE) was conducted at 400, 800, 1200, and 1600 rpm. The catalyst exhibited a higher methanol tolerance and long term durability with respect to commercial Pt/C. The results for MnO₂-CNT show that the low-cost catalyst will supplant the expensive Pt/C catalyst in the fuel cell.

Keywords: carbon nanotubes, methanol fuel cell, oxygen reduction reaction, MnO₂-CNTs

Procedia PDF Downloads 125

Authors: Sarre Nzaba, Bulelwa Ntsendwana, Bekkie Mamba, Alex Kuvarega

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The discharge of azo dyes such as Brilliant black (BB) into the water bodies has carcinogenic and mutagenic effects on humankind and the ecosystem. Conventional water treatment techniques fail to degrade these dyes completely thereby posing more problems. Advanced oxidation processes (AOPs) are promising technologies in solving the problem. Anatase type nitrogen-platinum (N, Pt) co-doped TiO₂ photocatalysts were prepared by a modified sol-gel method using amine terminated polyamidoamine generation 1 (PG1) as a template and source of nitrogen. The resultant photocatalysts were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), UV‐Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy (PL), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (RS), thermal gravimetric analysis (TGA). The results showed that the calcination atmosphere played an important role in the morphology, crystal structure, spectral absorption, oxygen vacancy concentration, and visible light photocatalytic performance of the catalysts. Anatase phase particles ranging between 9- 20 nm were also confirmed by TEM, SEM, and analysis. The origin of the visible light photocatalytic activity was attributed to both the elemental N and Pd dopants and the existence of oxygen vacancies. Co-doping imparted a shift in the visible region of the solar spectrum. The visible light photocatalytic activity of the samples was investigated by monitoring the photocatalytic degradation of brilliant black dye. Co-doped TiO₂ showed greater photocatalytic brilliant black degradation efficiency compared to singly doped N-TiO₂ or Pd-TiO₂ under visible light irradiation. The highest reaction rate constant of 3.132 x 10-2 min⁻¹ was observed for N, Pd co-doped TiO₂ (2% Pd). The results demonstrated that the N, Pd co-doped TiO₂ (2% Pd) sample could completely degrade the dye in 3 h, while the commercial TiO₂ showed the lowest dye degradation efficiency (52.66%).

Keywords: brilliant black, Co-doped TiO₂, polyamidoamine generation 1 (PAMAM G1), photodegradation

Procedia PDF Downloads 178

Authors: Farha Mizana Shamsudin, Shahidan Radiman, Yusof Abdullah, Nasri Abdul Hamid

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Oxide dispersion strengthened (ODS) ferritic steels are amongst the most promising candidates for large scale structural materials to be applied in next generation fission and fusion nuclear power reactors. This kind of material is relatively stable at high temperature, possess remarkable mechanical properties and comparatively good resistance from neutron radiation damage. The superior performance of ODS ferritic steels over their conventional properties is attributed to the high number density of nano-sized dispersoids that act as nucleation sites and stable sinks for many small helium bubbles resulting from irradiation, and also as pinning points to dislocation movement and grain growth. ODS ferritic steels are usually produced by powder metallurgical routes involving mechanical alloying (MA) process of Y2O3 and pre-alloyed or elemental metallic powders, and then consolidated by hot isostatic pressing (HIP) or hot extrusion (HE) techniques. In this study, Fe-14Cr-3W-0.5Ti-0.3Y₂O₃ (designated as 14YWT) was produced by mechanical alloying process and followed by hot isostatic pressing (HIP) technique. Crystal structure and morphology of this sample were identified and characterized by using X-ray Diffraction (XRD) and field emission scanning electron microscope (FESEM) respectively. The magnetic measurement of this sample at room temperature was carried out by using a vibrating sample magnetometer (VSM). FESEM micrograph revealed a homogeneous microstructure constituted by fine grains of less than 650 nm in size. The ultra-fine dispersoids of size between 5 nm to 19 nm were observed homogeneously distributed within the BCC matrix. The EDS mapping reveals that the dispersoids contain Y-Ti-O nanoclusters and from the magnetization curve plotted by VSM, this sample approaches the behavior of soft ferromagnetic materials. In conclusion, ODS Fe-14Cr-3W-0.5Ti-0.3Y₂O₃ (14YWT) ferritic steel was successfully produced by HIP technique in this present study.

Keywords: hot isostatic pressing, magnetization, microstructure, ODS ferritic steel

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Authors: F. Zouai, F. Z. Benabid, S. Bouhelal, D. Benachour

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Nanocomposite polymer / clay are relatively important area of research. These reinforced plastics have attracted considerable attention in scientific and industrial fields because a very small amount of clay can significantly improve the properties of the polymer. The polymeric matrices used in this work are two saturated polyesters ie polyethylene terephthalate (PET) and polyethylene naphthalate (PEN).The success of processing compatible blends, based on poly(ethylene terephthalate) (PET)/ poly(ethylene naphthalene) (PEN)/clay nanocomposites in one step by reactive melt extrusion is described. Untreated clay was first purified and functionalized ‘in situ’ with a compound based on an organic peroxide/ sulfur mixture and (tetramethylthiuram disulfide) as the activator for sulfur. The PET and PEN materials were first separately mixed in the molten state with functionalized clay. The PET/4 wt% clay and PEN/7.5 wt% clay compositions showed total exfoliation. These compositions, denoted nPET and nPEN, respectively, were used to prepare new n(PET/PEN) nanoblends in the same mixing batch. The n(PET/PEN) nanoblends were compared to neat PET/PEN blends. The blends and nanocomposites were characterized using various techniques. Microstructural and nanostructural properties were investigated. Fourier transform infrared spectroscopy (FTIR) results showed that the exfoliation of tetrahedral clay nanolayers is complete and the octahedral structure totally disappears. It was shown that total exfoliation, confirmed by wide angle X-ray scattering (WAXS) measurements, contributes to the enhancement of impact strength and tensile modulus. In addition, WAXS results indicated that all samples are amorphous. The differential scanning calorimetry (DSC) study indicated the occurrence of one glass transition temperature Tg, one crystallization temperature Tc and one melting temperature Tm for every composition. This was evidence that both PET/PEN and nPET/nPEN blends are compatible in the entire range of compositions. In addition, the nPET/nPEN blends showed lower Tc and higher Tm values than the corresponding neat PET/PEN blends. In conclusion, the results obtained indicate that n(PET/PEN) blends are different from the pure ones in nanostructure and physical behavior.

Keywords: blends, exfoliation, DRX, DSC, montmorillonite, nanocomposites, PEN, PET, plastograph, reactive melt-mixing

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Authors: L. Ebralidze, A. Tsertsvadze, D. Berashvili, A. Bakuridze

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Current cancer therapy strategies are based on surgery, radiotherapy and chemotherapy. The problems associated with chemotherapy are one of the biggest challenges for clinical medicine. These include: low specificity, broad spectrum of side effects, toxicity and development of cellular resistance. Therefore, anti-cance drugs need to be develop urgently. Particularly, in order to increase efficiency of anti-cancer drugs and reduce their side effects, scientists work on formulation of nano-drugs. The objective of this study was to develop composition and technology of vincristine nanoparticles using high-molecular carbohydrates of plant origin. Plant polysacharides, particularly, soy bean seed polysaccharides, flaxseed polysaccharides, citrus pectin, gum arabic, sodium alginate were used as objects. Based on biopharmaceutical research, vincristine containing nanoparticle formulations were prepared. High-energy emulsification and solvent evaporation methods were used for preparation of nanosystems. Polysorbat 80, polysorbat 60, sodium dodecyl sulfate, glycerol, polyvinyl alcohol were used in formulation as emulsifying agent and stabilizer of the system. The ratio of API and polysacharides, also the type of the stabilizing and emulsifying agents are very effective on the particle size of the final product. The influence of preparation technology, type and concentration of stabilizing agents on the properties of nanoparticles were evaluated. For the next stage of research, nanosystems were characterized. Physiochemical characterization of nanoparticles: their size, shape, distribution was performed using Atomic force microscope and Scanning electron microscope. The present study explored the possibility of production of NPs using plant polysaccharides. Optimal ratio of active pharmaceutical ingredient and plant polysacharids, the best stabilizer and emulsifying agent was determined. The average range of nanoparticles size and shape was visualized by SEM.

Keywords: nanoparticles, target delivery, natural high molecule carbohydrates, surfactants

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Authors: John Olorunfemi Abe, Olawale Muhammed Popoola, Abimbola Patricia Idowu Popoola

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Hydrogen is an appealing alternative to fossil fuels because of its abundance, low weight, high energy density, and relative lack of contaminants. However, its low density presents a number of storage challenges. Therefore, this work studies the influence of refractory nitride additives consisting of 5 wt. % each of hexagonal boron nitride (h-BN), titanium nitride (TiN), and aluminum nitride (AlN) on hydrogen storage and electrochemical characteristics of Ti6Al4V-based materials produced by spark plasma sintering. The microstructure and phase constituents of the sintered materials were characterized using scanning electron microscopy (in conjunction with energy-dispersive spectroscopy) and X-ray diffraction, respectively. Pressure-composition-temperature (PCT) measurements were used to assess the hydrogen absorption/desorption behavior, kinetics, and storage capacities of the sintered materials, respectively. The pure Ti6Al4V alloy displayed a two-phase (α+β) microstructure, while the modified composites exhibited apparent microstructural modifications with the appearance of nitride-rich secondary phases. It is found that the diffusion process controls the kinetics of the hydrogen absorption. Thus, a faster rate of hydrogen absorption at elevated temperatures ensued. The additives acted as catalysts, lowered the activation energy and accelerated the rate of hydrogen sorption in the composites relative to the monolithic alloy. Ti6Al4V-5 wt. % h-BN appears to be the most promising candidate for hydrogen storage (2.28 wt. %), followed by Ti6Al4V-5 wt. % TiN (2.09 wt. %), whereas Ti6Al4V-5 wt. % AlN shows the least hydrogen storage performance (1.35 wt. %). Accordingly, the developed hydride system (Ti6Al4V-5h-BN) may be competitive for use in applications involving short-range continuous vehicles (~50-100km) as well as stationary applications such as electrochemical devices, large-scale storage cylinders in hydrogen production locations, and hydrogen filling stations.

Keywords: hydrogen storage, Ti6Al4V hydride system, pressure-composition-temperature measurements, refractory nitride additives, spark plasma sintering, Ti6Al4V-based materials

Procedia PDF Downloads 72