Search results for: advantages

Authors: Hassan M. Albishri, Fatimah Al-Shehri, Deia Abd El-Hady

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Among the analytical techniques, reverse phase liquid chromatography (RPLC) is currently used in pharmaceutical industry. Ecofriendly analytical chemistry offers the advantages of decreasing the environmental impact with the advantage of increasing operator safety which constituted a topic of industrial interest. Recently, ionic liquids have been successfully used to reduce or eliminate the conventional organic toxic solvents. In the current work, a simple and ecofriendly ionic liquid modified RPLC (IL-RPLC) method has been firstly developed and compared with RPLC under acidic and neutral mobile phase conditions for simultaneous determination of atorvastatin-calcium, rosuvastatin and simvastatin. Several chromatographic effective parameters have been changed in a systematic way. Adequate results have been achieved by mixing ILs with ethanol as a mobile phase under neutral conditions at 1 mL/min flow rate on C18 column. The developed IL-RPLC method has been validated for the quantitative determination of drugs in pharmaceutical formulations. The method showed excellent linearity for analytes in a wide range of concentrations with acceptable precise and accurate data. The current IL-RPLC technique could have vast applications particularly under neutral conditions for simple and greener (bio)analytical applications of pharmaceuticals.

Keywords: ionic liquid, RPLC, anti-hyperlipidemic drugs, ecofriendly

Procedia PDF Downloads 252

Authors: Mikko Hänninen

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This paper explores the effect online retail platforms have on customer behavior and retail patronage through an inductive multi-case study. Existing research on retail platforms and ecosystems generally focus on competition between platform members and most papers maintain a managerial perspective with customers seen mainly as merely one stakeholder of the value-exchange relationship. It is proposed that retail platforms change the nature of customer relationships compared to traditional brick-and-mortar or e-commerce retailers. With online retail platforms such as Alibaba, Amazon and Rakuten gaining increasing traction with their platform based business models, the purpose of this paper is to define retail platforms and look at how leading retail platforms are able to create value for their customers, in order to foster meaningful customer’ relationships. An analysis is conducted on the major global retail platforms with a focus specifically on understanding the tools in place for creating customer value in order to show how retail platforms create and maintain customer relationships for fostering customer loyalty. The results describe the opportunities and challenges retailers face when competing against platform based businesses and outline the advantages as well as disadvantages that platforms bring to individual consumers. Based on the inductive case research approach, five theoretical propositions on consumer behavior in online retail platforms are developed that also form the basis of further research with this research making both a practical as well as theoretical contribution to platform research streams.

Keywords: retail, platform, ecosystem, e-commerce, loyalty

Procedia PDF Downloads 279

Authors: Pratibha Srivastava, Chithra V. J., Sudhakar S., Nitin K. D.

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A closed-loop system comprises of a controller, a response system, and an actuating system. The controller, which is the system under test for us, excites the actuators based on feedback from the sensors in a periodic manner. The sensors should provide the feedback to the System Under Test (SUT) within a deterministic time post excitation of the actuators. Any delay or miss in the generation of response or acquisition of excitation pulses may lead to control loop controller computation errors, which can be catastrophic in certain cases. Such systems categorised as hard real-time systems that need special strategies. The real-time operating systems available in the market may be the best solutions for such kind of simulations, but they pose limitations like the availability of the X Windows system, graphical interfaces, other user tools. In this paper, we present strategies that can be used on a general purpose operating system (Bare Linux Kernel) to achieve a deterministic deadline and hence have the added advantages of a GPOS with real-time features. Techniques shall be discussed how to make the time-critical application run with the highest priority in an uninterrupted manner, reduced network latency for distributed architecture, real-time data acquisition, data storage, and retrieval, user interactions, etc.

Keywords: real time data acquisition, real time kernel preemption, scheduling, network latency

Procedia PDF Downloads 142

Authors: Animesh Gupta

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Objective: The purpose of this study is to evaluate the versatility and outcome of lateral supra malleolar flap (LSMF) in soft tissue reconstruction of the regions including the distal leg, ankle, dorsal foot and heel. Methods: From March 2021 to April 2023, 18 patients with soft tissue defects in the regions, including the distal leg, ankle, dorsal foot and heel, who underwent LSMF repair for lower limb wound reconstruction were analyzed. The location, size of the defects, etiology, outcome, complications, and other alternative options were studied and presented. Results: The follow-up period of the cases was 3-6 months after surgery. All flaps were successful; however, one flap was complicated by venous congestion and was managed by loosening a few sutures and the patient was required to elevate the affected limb to resolve the issue. Conclusion: The LSMF has numerous advantages in repairing soft tissue defects in areas involving the ankle, distal leg, heel and dorsum of the foot. In comparison to reverse sural flaps for repairing defects in the heel and lower leg, LSMF offers shorter operation time, shorter hospitalization, lower cost, and fewer postoperative complications.

Keywords: lateral supra malleolar flap, LSMF, soft tissue reconstruction, lower leg defect

Procedia PDF Downloads 69

Authors: Zhihao Zheng, Zhilin Wang, Linxin Liu

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In the research of automated knowledge question-answering systems, accuracy and efficiency are critical challenges. This paper proposes a knowledge graph-enhanced Retrieval-Augmented Generation (RAG) method, combined with a Graph Neural Network (GNN) structure, to automatically determine the correctness of knowledge competition questions. First, a domain-specific knowledge graph was constructed from a large corpus of academic journal literature, with key entities and relationships extracted using Natural Language Processing (NLP) techniques. Then, the RAG method's retrieval module was expanded to simultaneously query both text databases and the knowledge graph, leveraging the GNN to further extract structured information from the knowledge graph. During answer generation, contextual information provided by the knowledge graph and GNN is incorporated to improve the accuracy and consistency of the answers. Experimental results demonstrate that the knowledge graph and GNN-enhanced RAG method perform excellently in determining the correctness of questions, achieving an accuracy rate of 95%. Particularly in cases involving ambiguity or requiring contextual information, the structured knowledge provided by the knowledge graph and GNN significantly enhances the RAG method's performance. This approach not only demonstrates significant advantages in improving the accuracy and efficiency of automated knowledge question-answering systems but also offers new directions and ideas for future research and practical applications.

Keywords: knowledge graph, graph neural network, retrieval-augmented generation, NLP

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Authors: Akram Boubakri, Fethi Choubeni, Tan Hoa Vuong, Jacques David

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The control of electromagnetic waves is a key aim of several researches over the past decade. In this regard, Metamaterials have shown a strong ability to manipulate the electromagnetic waves on a subwavelength scales thanks to its unconventional properties that are not available in natural materials such as negative refraction index, super imaging and invisibility cloaking. Metalenses were used to avoid some drawbacks presented by conventional lenses since focusing with conventional lenses suffered from the limited resolution because they were only able to focus the propagating wave component. Nevertheless, Metalenses were able to go beyond the diffraction limit and enhance the resolution not only by collecting the propagating waves but also by restoring the amplitude of evanescent waves that decay rapidly when going far from the source and that contains the finest details of the image. Metasurfaces have many mechanical advantages over three-dimensional metamaterial structures especially the ease of fabrication and a smaller required volume. Those structures have been widely used for antenna performance improvement and to build flat metalenses. In this work, we showed that a well-designed metasurface lens operating at the frequency of 5.9GHz, has efficiently enhanced the radiation characteristics of a patch antenna and can be used for WLAN applications (IEEE 802.11 a). The proposed metasurface lens is built with a geometrically modified unit cells which lead to a change in the response of the lens at different position and allow the control of the wavefront beam of the incident wave thanks to the gradient refractive index.

Keywords: focusing, gradient index, metasurface, metalens, WLAN Applications

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Authors: Sarra Boughaba

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α-aminophosphonates have found a wide range of applications in organic and medicinal chemistry; they are considered as pharmacological agents, anti-inflammatory antitumor agents, and antibiotics. A number of procedures have been developed for their synthesis. However, many of these methods suffer from some disadvantages such as long reaction times, environmental pollution, utilization of organic solvents, and expensive catalysts. In the past few years, heteropolyacids have received great attention as environmentally benign catalysts for organic synthetic processes, they possess unique physicochemical properties, such as super-acidity, high thermal and chemical stability, ability to accept and release electrons and high proton mobility, and the possibility of varying their acidity and oxidizing potential. In this context, an efficient and eco-friendly protocol has been described for the synthesis of α-aminophosphonates via one pot, three component reaction catalyzed by H₆P₂W₁₈O₆₂.14H₂O as reusable catalyst, by condensation of amino acids esters, various aromatic aldehydes and triethylphosphite under solvent-free conditions, the corresponding α-aminophosphonates were formed in good yields as racemic or diastereomericmixture. All the new products were systematically characterized by IR, MS, and ¹H, ¹³C-³¹P-NMR analyses. This method offers advantages such as simplicity workup with the green aspects by avoiding expensive catalysts and toxic solvents, good yields, short reaction times.

Keywords: amino acids esters, α-aminophosphonates, H₆P₂W₁₈O₆₂.14H₂O catalyst, green chemistry

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Authors: Monjurul Hasan, Golam Kibria, Abdus Salam

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Pervious concrete is a form of lightweight porous concrete, obtained by eliminating the fine aggregate from the normal concrete mix. The advantages of this type of concrete are lower density, lower cost due to lower cement content, lower thermal conductivity, relatively low drying shrinkage, no segregation and capillary movement of water. In this paper an investigation is made on the mechanical response of the pervious concrete at zero fine level (zero fine concrete) made with local brick aggregate. Effect of aggregate size variation on the strength, void ratio and permeability of the zero fine concrete is studied. Finally, a comparison is also presented between the stone aggregate made pervious concrete and brick aggregate made pervious concrete. In total 75 concrete cylinder were tested for compressive strength, 15 cylinder were tested for void ratio and 15 cylinder were tested for permeability test. Mix proportion (cement: Coarse aggregate) was kept fixed at 1:6 (by weights), where water cement ratio was valued 0.35 for preparing the sample specimens. The brick aggregate size varied among 25mm, 19mm, 12mm. It has been found that the compressive strength decreased with the increment of aggregate size but permeability increases and concrete made with 19mm maximum aggregate size yields the optimum value. No significant differences on the strength and permeability test are observed between the brick aggregate made zero fine concrete and stone aggregate made zero fine concrete.

Keywords: pervious concrete, brick aggregate concrete, zero fine concrete, permeability, porosity

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Authors: Ki-seok Kwon, Dong-woo Ryu, Heung-Youl Kim

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Although high-strength concrete has many advantages over generic concrete at normal temperatures (around 20℃), it undergoes spalling at high temperatures, which constitutes its structurally fatal drawback. In this study, fire resistance tests were conducted for 3 hours in accordance with ASTM E119 on bearing wall specimens which were 3,000mm x 3,000mm x 300mm in dimensions to investigate the influence the type of admixtures would exert on the fire resistance performance of high-strength concrete. Portland cement, blast furnace slag, fly ash and silica fume were used as admixtures, among which 2 or 3 components were combined to make 7 types of mixtures. In 56MPa specimens, the severity of spalling was in order of SF5 > F25 > S65SF5 > S50. Specimen S50 where an admixture consisting of 2 components was added did not undergo spalling. In 70MPa specimens, the severity of spalling was in order of SF5 > F25SF5 > S45SF5 and the result was similar to that observed in 56MPa specimens. Acknowledgements— This study was conducted by the support of the project, “Development of performance-based fire safety design of the building and improvement of fire safety” (18AUDP-B100356-04) which is under the management of Korea Agency for Infrastructure Technology Advancement as part of the urban architecture research project for the Ministry of Land, Infrastructure and Transport, for which we extend our deep thanks.

Keywords: high strength concrete, mineral admixture, fire resistance, social disaster

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Authors: Bahareh Asefi, Fereidoun Farzaneh, Ghazaleh Asefi

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Continuous increasing food waste produced on a global as well as national scale may lead to burgeoning environmental and economic problems. Simultaneously, decreasing the use efficiencies of natural resources such as land, water, and energy is occurring. On the other hand, food waste has a high-energy content, which seems ideal to achieve dual benefits in terms of energy recovery and the improvement of resource use efficiencies. Therefore, to decrease the environmental impacts of food waste and resource conservation, the researcher has focused on traditional methods of using food waste as a resource through different approaches such as anaerobic digestion, composting, incineration, and landfill. The adverse environmental effects of growing food waste make it difficult for traditional food waste treatment and management methods to balance social, economic, and environmental benefits. The old technology does not need to develop, but several new technologies such as microbial fuel cells, food waste disposal, and bio-converting food waste technology still need to establish or appropriately considered. It is pointed out that some new technologies can take into account various benefits. Since the information about food waste and its management method is critical for executable policy, a review of the latest information regarding the source of food waste and its management technology in some counties is provided in this study.

Keywords: food waste, management technology, innovative method, bio converting food waste, microbial fuel cell

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Authors: Tie-Qing Zhang, Seunghun Jung, Young-Bae Kim

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This research is devoted to developing a membrane reactor to flexibly meet the hydrogen demand of onboard fuel cells, which is an important part of green energy development. Among many renewable chemical products, dimethyl ether (DME) has the advantages of low reaction temperature (400 °C in this study), high hydrogen atom content, low toxicity, and easy preparation. Autothermal reforming, on the other hand, has a high hydrogen recovery rate and exhibits thermal neutrality during the reaction process, so the additional heat source in the hydrogen production process can be omitted. Therefore, the DME auto thermal reforming process was adopted in this study. To control the temperature of the reaction catalyst bed and hydrogen production rate, a Model Predictive Control (MPC) scheme was designed. Taking the above two variables as the control objectives, stable operation of the reformer can be achieved by controlling the flow rates of DME, steam, and high-purity air in real-time. To prevent catalyst poisoning in the fuel cell, the hydrogen needs to be purified to reduce the carbon monoxide content to below 50 ppm. Therefore, a Pd-Ag hydrogen semi-permeable membrane with a thickness of 3-5 μm was inserted into the auto thermal reactor, and the permeation efficiency of hydrogen was improved by steam purging on the permeation side. Finally, hydrogen with a purity of 99.99 was obtained.

Keywords: hydrogen production, auto thermal reforming, membrane, fuel cell

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Authors: Elmahdi Khalil, Saad Enniari, Mostapha Zbakh

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Cloud computing promises to increase innovation and the velocity with witch applications are deployed, all while helping any enterprise meet most IT service needs at a lower total cost of ownership and higher return investment. As the march of cloud continues, it brings both new opportunities and new security challenges. To take advantages of those opportunities while minimizing risks, we think that Intrusion Detection Systems (IDS) integrated in the cloud is one of the best existing solutions nowadays in the field. The concept of intrusion detection was known since past and was first proposed by a well-known researcher named Anderson in 1980's. Since that time IDS's are evolving. Although, several efforts has been made in the area of Intrusion Detection systems for cloud computing environment, many attacks still prevail. Therefore, the work presented in this paper proposes a multi criteria analysis and a comparative study between several IDS architectures designated to work in a cloud computing environments. To achieve this objective, in the first place we will search in the state of the art of several consistent IDS architectures designed to work in a cloud environment. Whereas, in a second step we will establish the criteria that will be useful for the evaluation of architectures. Later, using the approach of multi criteria decision analysis Mac Beth (Measuring Attractiveness by a Categorical Based Evaluation Technique we will evaluate the criteria and assign to each one the appropriate weight according to their importance in the field of IDS architectures in cloud computing. The last step is to evaluate architectures against the criteria and collecting results of the model constructed in the previous steps.

Keywords: cloud computing, cloud security, intrusion detection/prevention system, multi-criteria decision analysis

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Authors: J. Švarc-Gajić, A. Cvetanović

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Apigenin is a flavone synthetized by many plants and quite abundant in chamomile (Matricaria recutita) in its free form and in the form of its glucoside and different acylated forms. Many beneficial health effects have been attributed to apigenin, such as chemo-preventive, anxiolytic, anti-inflammatory, antioxidant and antispasmodic. It is reported that free apigenin is much more bioactive in comparison to its bound forms. Subcritical water offers numerous advantages in comparison to conventional extraction techniques, such as good selectivity, low price and safety. Superheated water exhibits high hydrolytical potential which must be carefully balanced when using this solvent for the extraction of bioactive molecules. Moderate hydrolytical potential can be exploited to liberate apigenin from its bound forms, thus increasing biological potential of obtained extracts. The polarity of pressurized water and its hydrolytical potential are highly dependent on the temperature. In this research chamomile ligulate flowers were extracted by pressurized hot water in home-made subcritical water extractor in conditions of convective mass transfer. The influence of the extraction temperature was investigated at 30 bars. Extraction yields of total phenols, total flavonoids and apigenin depending on the operational temperature were calculated based on spectrometric assays. Optimal extraction temperature for maximum yields of total phenols and flavonoids showed to be 160°C, whereas apigenin yield was the highest at 120°C.

Keywords: superheated water, temperature, chamomile, apigenin

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Authors: Abdelkader Anouzla, Soukaina Bouaouda, Roukaya Bouyakhsass, Salah Souabi, Abdeslam Taleb

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During storage and under the combined action of rainwater and natural fermentation, these wastes produce over 800.000 m3 of landfill leachates. Due to population growth and changing global economic activities, the amount of waste constantly generated increases, making more significant volumes of leachate. Leachate, when leaching into the soil, can negatively impact soil, surface water, groundwater, and the overall environment and human life. The leachate must first be treated because of its high pollutant load before being released into the environment. This article reviews the different leachate treatments in September 2022 techniques. Different techniques can be used for this purpose, such as biological, physical-chemical, and membrane methods. Young leachate is biodegradable; in contrast, these biological processes lose their effectiveness with leachate aging. They are characterized by high ammonia nitrogen concentrations that inhibit their activity. Most physical-chemical treatments serve as pre-treatment or post-treatment to complement conventional treatment processes or remove specific contaminants. After the introduction, the different types of pollutants present in leachates and their impacts have been made, followed by a discussion highlighting the advantages and disadvantages of the various treatments, whether biological, physicochemical, or membrane. From this work, due to their simplicity and reasonable cost compared to other treatment procedures, biological treatments offer the most suitable alternative to limit the effects produced by the pollutants in landfill leachates.

Keywords: landfill leachate, landfill pollution, impact, wastewater

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Authors: Min Pan, An-Hsu Chen

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Burnout has been proved to be one of the factors that hinder the development and sport performances of athletes while moral disengagement is the psychological mechanism used by athletes to elevate the guilt caused by conducting the anti-social behaviors to gain competitive advantages and in sports which have both been discussed extensively. The sports devaluation in burnout may undermine the sportsmanship of athletes therefore may serve as one of factors of moral disengagement in sports. Nonetheless, the connection between athlete burnout and moral disengagement in sports is yet established. Hence, the study aims to investigate whether there is the correlation between athlete burnout and moral disengagement in sports. Participants of this study are 120 collegiate athletes who specialize in seven different sports (e.g., fence, boxing, taekwondo, and etc.) with average training hours of 3.7 per day and 4.5 days per week. Athlete Burnout Questionnaire and Moral Disengagement in Sports – Short were administrated as the research instruments. Data collected were analyzed with descriptive statistics, t-test, one-way ANOVA, and step-wise regression. The results show, participants demonstrate mild to moderate burnout and moral disengagement in their perspective sports disciplines. Moreover, athletes specialize in different sports experience distinct burnout situations while there is no significant variation of moral disengagement in different sports. It is also found, moral disengagement in sports has significant and positive correlations with emotional and physical exhaustion as well as sports devaluation in athlete burnout. Furthermore, athlete burnout can positively predict moral disengagement in sports while sports devaluation plays an important role within. It can be concluded that, athlete burnout may contribute to their tendency of moral disengagement in sport. By relieving the burnout level may help improve their moral disengagement inclination in sports. The finding may contribute to the current literature regarding athlete burnout and moral disengagement in sports.

Keywords: athlete burnout, dehumanization, moral disengagement, reduced sense of accomplishment

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Authors: Kiomars Habibi, Mostafa Behzadfar, Airin Jaberi

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Designing appropriate places for the comfort of pedestrians is one of the most important aspects of modern urbanization and renovation and rehabilitation stimulus of urban old fabrics. So, that special cities designed for pedestrians with a complete network of streets without cars, can be considered as one of the best habitations in the world. The number of these cities with a network of streets and squares in which beauty, enjoyment and comfort are mostly concerned for the pedestrians designed regions is increasing around the world, such as Stockholm, Copenhagen, Munich, Frankfurt, Venice, Rome, etc. In this paper, we are going to explain the influential factors regarding the efficiency of these cities by identifying one of the most important pedestrian ways of the world; Strøget is a car free zone in Copenhagen, Denmark. This popular tourist attraction in the center of town is the longest pedestrian shopping area in Europe. Analyses indicate that world-wide experience concerning the renovation and rehabilitation of old fabrics has many advantages in exploiting the idea of pedestrian way for regeneration of old fabrics. Transforming the streets to appropriate places for the comfort of pedestrians, expanding the public spaces such as city squares, and decreasing the masses of building alongside the brought comfort and peace is the main reason in the success of Strøget pedestrian street in urban old fabrics of Copenhagen. Hypothesis: The Strøget pedestrian street has been the development stimulus in Copenhagen and the urban old fabrics development as a result

Keywords: development, stimulus, pedestrian street, urban landscape, Stroget

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Authors: Ergun Sakalar, Kubra Bilgic

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In the last decades, real-time PCR has become a reliable tool preferred to use in many laboratories for pathogen detection. This technique allows for monitoring target amplification via fluorescent molecules besides admit of quantitative analysis by enabling of convert outcomes of thermal cycling to digital data. Sensitivity and traceability of real-time PCR are based on measuring of fluorescence that appears only when fluorescent reporter dye bound to specific target DNA.The fluorescent reporter systems developed for this purpose are divided into two groups. The first group consists of intercalator fluorescence dyes such as SYBR Green, EvaGreen which binds to double-stranded DNA. On the other hand, the second group includes fluorophore-labeled oligonucleotide probes that are separated into three subgroups due to differences in mechanism of action; initial primer-probes such as Cyclicons, Angler®, Amplifluor®, LUX™, Scorpions, and the second one hydrolysis probes like TaqMan, Snake assay, finally hybridization probes, for instance, Molecular Beacons, Hybprobe/FRET, HyBeacon™, MGB-Eclipse, ResonSense®, Yin-Yang, MGB-Pleiades. In addition nucleic acid analogues, an increase of probe affinity to target site is also employed with fluorescence-labeled probes. Consequently, abundant real-time PCR detection chemistries are chosen by researcher according to the field of application, mechanism of action, advantages, and proper structures of primer/probes.

Keywords: fluorescent dye, food safety, molecular probes, nucleic acid analogues

Procedia PDF Downloads 251

Authors: Siriwan Nantaphol, Robert B. Channon, Takeshi Kondo, Weena Siangproh, Orawon Chailapakul, Charles S. Henry

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In this work, we demonstrate a novel electrochemically reduced graphene oxide (ERGO) modified boron-doped diamond paste (BDDP) electrode on paper-based analytical devices (PADs) for simultaneous determination of norepinephrine (NE) and serotonin (5-HT). The BDD paste electrode was easily constructed by filling BDD paste in small channels, which made in transparency film sheets using a CO₂ laser etching 
system. The counter and reference electrodes were fabricated on paper by in-house screen-printing and then combined with BDD paste microelectrode. The electrochemical characterization of the device was investigated by cyclic voltammetry (CV). Differential pulse voltammetry (DPV) was employed for the simultaneous determination of NE and 5-HT. The ERGO-modified BDDP electrode displayed excellent electrocatalytic activities toward the oxidation of NE and 5-HT and strong function for resolving the overlapping voltammetric responses of NE and 5-HT into two well-defined voltammetric peaks. This device was capable of simultaneously detecting NE and 5-HT in wide concentration ranges and with a low limit of detections. In addition, it has the advantages in terms of ease of use, low cost, and disposability.

Keywords: boron-doped diamond paste electrode, electrochemically reduced graphene oxide, norepinephrine, paper-based analytical device, serotonin

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Authors: Chung-Hyeon Ryu, Do-Hyoung Kim, Hak-Sung Kim

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As the use of the composites was increased, the detecting method of hidden damages which have an effect on performance of the composite was important. Terahertz (THz) spectroscopy was assessed as one of the new powerful nondestructive evaluation (NDE) techniques for fiber reinforced composite structures because it has many advantages which can overcome the limitations of conventional NDE techniques such as x-rays or ultrasound. The THz wave offers noninvasive, noncontact and nonionizing methods evaluating composite damages, also it gives a broad range of information about the material properties. In additions, it enables to detect the multiple-delaminations of various nonmetallic materials. In this study, the pulse type THz spectroscopy imaging system was devised and used for detecting and evaluating the hidden delamination in the glass fiber reinforced plastic (GFRP) composite laminates. The interaction between THz and the GFRP composite was analyzed respect to the type of delamination, including their thickness, size and numbers of overlaps among multiple-delaminations in through-thickness direction. Both of transmission and reflection configurations were used for evaluation of hidden delaminations and THz wave propagations through the delaminations were also discussed. From these results, various hidden delaminations inside of the GFRP composite were successfully detected using time-domain THz spectroscopy imaging system and also compared to the results of C-scan inspection. It is expected that THz NDE technique will be widely used to evaluate the reliability of composite structures.

Keywords: terahertz, delamination, glass fiber reinforced plastic composites, terahertz spectroscopy

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Authors: Nadia Allouache, Omar Rahli

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Many promising technologies have been developed to harness the sun's energy. These technologies help in economizing energy and environmental protection. The solar refrigerating systems are one of these important technologies. In addition to environmental benefits and energy saving, adsorption refrigerating systems have many advantages such as lack of moving parts, simplicity of construction and low operating costs. The work aimed to establish the main factors that affect the performances of an adsorption refrigerating system using different geometries of adsorbers and different adsorbent-adsorbate pairs. The numerical modeling of the heat and mass transfer in the system, using various working pairs, such as: activated carbon-ammonia, calcium chlorid-ammonia, activated carbon fiber- methanol and activated carbon AC35-methanol, show that the adsorber design can influence the system performances; The thermal performances of system are better in the annular configuration case. An optimal value of generating temperature is observed in annular adsorber case for which the thermal performance of the cooling system is maximal. While in the plate adsorber, above a certain value of generating temperature, the performance of the system remains almost constant. The environmental conditions such as solar radiation and pressure have a great influence in the system efficiency, and the choice of the working pair depends on the environmental conditions and the geometry of the adsorber.

Keywords: adsorber geometry, numerical modeling, optimal environmental conditions, working pairs.

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Authors: Ruben Molina, Melissa Ochoa

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The rapid expansion and facilities that the Chinese government has granted to its inhabitants to travel abroad has brought benefits to the economies of the countries where these tourists travel. Due to the great economic spill that these tourists make in their travels and the great potential they possess, they become one of the most attractive segments in the world, causing countries to seek to attract them for the profits. The Chinese tourist is a tourist who seeks to know the culture, culinary experiences, traditions and folklore of the place where they travel, more than seeking sun and beach. Mexico is a country that has a great mix of tourist products and services, which favors that the tourism offer focuses on the satisfaction of the needs and preferences of the different segments of international tourists who arrive in Mexico: sun and beach tourism and also cultural tourism. Mexico has 51 sites inscribed on the World Heritage List, of which 12 are natural, 37 are cultural and 2 are mixed. Despite the great tourist attraction of the country and the strategic importance of the sector for the economy, Mexico has not managed to have a large number of tourists or income from international tourism for 15 years. One way to increase the travel industry is to attract the Chinese tourist to Mexico, which is considered a priority by countries like the United States, France and Spain due to the advantages they entail. Therefore, this article will describe the tastes, preferences and habits of Chinese tourists coming to the most popular destinations in Mexico through a Likert scale and it will be described which are the most attractive cultural factors in Mexico for the Chinese tourists and will be proposing strategies of attraction for Mexico and its destinations.

Keywords: attraction, Chinese tourist, cultural tourism, strategic, Mexico

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Authors: Asifa Amara, Prachi Singh, Kanishka, Debargho Pathak, Akshat Kumar, Jayakumar Eravelly

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Today's generation is totally dependent on technology that uses data as its fuel. The present study is all about innovations and developments in data science and gives an idea about how efficiently to use the data provided. This study will help to understand the core concepts of data science. The concept of artificial intelligence was introduced by Alan Turing in which the main principle was to create an artificial system that can run independently of human-given programs and can function with the help of analyzing data to understand the requirements of the users. Data science comprises business understanding, analyzing data, ethical concerns, understanding programming languages, various fields and sources of data, skills, etc. The usage of data science has evolved over the years. In this review article, we have covered a part of data science, i.e., machine learning. Machine learning uses data science for its work. Machines learn through their experience, which helps them to do any work more efficiently. This article includes a comparative study image between human understanding and machine understanding, advantages, applications, and real-time examples of machine learning. Data science is an important game changer in the life of human beings. Since the advent of data science, we have found its benefits and how it leads to a better understanding of people, and how it cherishes individual needs. It has improved business strategies, services provided by them, forecasting, the ability to attend sustainable developments, etc. This study also focuses on a better understanding of data science which will help us to create a better world.

Keywords: data science, machine learning, data analytics, artificial intelligence

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Authors: Huang Haoxin

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Large dark current at room temperature has long been the major bottleneck that impedes the development of high-performance infrared photodetectors towards miniaturization and integration. Although infrared photodetectors based on layered 2D narrow bandgap semiconductors have shown admirable advantages compared with those based on conventional compounds, which typically suffer from expensive cryogenic operations, it is still urgent to develop a simple but effective strategy to further reduce the dark current. Herein, a tellurium (Te) based infrared photodetector is reported with a specifically designed asymmetric electrical contact area. The deliberately introduced asymmetric electrical contact raises the electric field intensity difference in the Te channel near the drain and the source electrodes, resulting in spontaneous asymmetric carrier diffusion under global infrared light illumination under zero bias. Specifically, the Te-based photodetector presents promising detector performance at room temperature, including a low dark current of≈1 nA, an ultrahigh photocurrent/dark current ratio of 1.57×10⁴, a high specific detectivity (D*) of 3.24×10⁹ Jones, and relatively fast response speed of ≈720 μs at zero bias. The results prove that the simple design of asymmetric electrical contact areas can provide a promising solution to high-performance 2D semiconductor-based infrared photodetectors working at room temperature.

Keywords: asymmetrical contact, tellurium, dark current, infrared photodetector, sensitivity

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Authors: Pei-Jung Wu, Ching-Ying Huang, Chih-Chia Lin, Chun-Han Li, Chien-Yuan Wang

Abstract:

The fuel cell market has considerable development potential, but the cost is still less competitive. Replacing the traditional graphite plate with a stainless steel plate as a bipolar plate can greatly reduce the weight and volume of the stack, and has more cost advantages. However, the passivation layer on the surface of stainless steel makes the contact resistance reach the ohmic level and reduces the performance of the fuel cell. Therefore, it is necessary to reduce the interfacial contact resistance through the surface treatment. In this research, the thickness, uniformity, interfacial contact resistance (ICR), and adhesion of the carbon-based layer was analyzed. On the other hand, the effect of coating properties on the performance of the fuel cell was verified through I-V tests. The results show that after coating the contact resistance is greatly reduced by three stages to the microohm level, and as the film thickness is reduced, the contact resistance is reduced from 229~118 mΩ-cm² to 135~73 mΩ-cm² at a general assembly pressure of 1 to 2 MPa., and the current density at 0.6 V increased from 485.7 mA/cm² to 575.7 mA/cm². This study verifies the importance of the uniformity and ICR of the coating on proton exchange membrane fuel cell (PEMFC), and the surface coating technology is the key to affecting the characteristics of the coating.

Keywords: contact resistance, proton exchange membrane fuel cell, PEMFC, SS bipolar plate, spray coating process

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Authors: S. Ataei, F. Sarrafzadeh Javadi, K. Gilani, E. Moazeni

Abstract:

Drug delivery systems using colloidal particulate carriers such as niosomes or liposomes have distinct advantages over conventional dosage forms because the particles can act as drug-containing reservoirs. These carriers play an increasingly important role in drug delivery. Niosomes are vesicular delivery systems which result from the self-assembly of hydrated surfactant. Niosomes are now widely studied as an attractive to liposomes because they alleviate the disadvantages associated with liposomes, such as chemical instability, variable purity of phospholipids and high cost. The encapsulation of drugs in niosomes can decrease drug toxicity, increase the stability of drug and increase the penetrability of drug in the location of application, and may reduce the dose and systemic side effect. Nowadays, Niosomes are used by the pharmaceutical industry in manufacturing skin medications, eye medication, in cosmetic formulas and these vesicular systems can be used to deliver aspiratory drugs. One way of improving dispersion in the water phase and solubility of the hydrophobic drug is to formulate in into niosomes. Itraconazole (ITZ) was chosen as a model hydrophobic drug. This drug is water insoluble (solubility ~ 1 ng/ml at neutral pH), is a broad-spectrum triazole antifungal agent and is used to treat various fungal disease. This study aims to investigate the capability of forming itraconazole niosomes with Spans, Tweens, Brijs as non-ionic surfactants. To this end, various formulations of niosomes have been studied with regard to parameters such as the degree of containment and particle size.

Keywords: physicochemical, non-ionic surfactant vesicles, itraconazole

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Authors: Mahdi Naeemi Nooghabi, Mohammad Tofiqu Arif

Abstract:

Gas Insulated Switchgears by using an insulation material named SF6 (Sulphur Hexafluoride) and its significant dielectric properties have been the only choice in urban areas and other polluted industries. However, the initial investment of GIS is more than conventional AIS substation, its total life cycle costs caused to reach huge amounts of electrical market share. SF6 environmental impacts on global warming, atmosphere depletion, and decomposing to toxic gases in high temperature situation, and highest rate in Global Warming Potential (GWP) with 23900 times of CO2e and a 3200-year period lifetime was the only undeniable concern of GIS substation. Efforts of international environmental institute and their politic supports have been able to lead SF6 emission reduction legislation. This research targeted to find an appropriate alternative for GIS substations to meet all advantages in land occupation area and to improve SF6 environmental impacts due to its leakage and emission. An innovative new conceptual design named Multi-Storey prepared a new AIS design similar in land occupation, extremely low Sf6 emission, and maximum greenhouse gas emission reduction. Surprisingly, by considering economic benefits due to carbon price saving, it can earn more than $675 million during the 30-year life cycle by replacing of just 25% of total annual worldly additional GIS switchgears.

Keywords: AIS substation, GIS substation, SF6, greenhouse gas, global warming potential, carbon price, emission

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Authors: Michael Gerges, Ograbe Ahiakwo, Martin Jaeger, Ahmad Asaad

Abstract:

Recent advances of Building Information Modeling (BIM) especially in the Middle East have increased remarkably. Dubai has been taking a lead on this by making it mandatory for BIM to be adopted for all projects that involve complex architecture designs. This is because BIM is a dynamic process that assists all stakeholders in monitoring the project status throughout different project phases with great transparency. It focuses on utilizing information technology to improve collaboration among project participants during the entire life cycle of the project from the initial design, to the supply chain, resource allocation, construction and all productivity requirements. In view of this trend, the paper examines the extent of applying BIM in the State of Kuwait, by exploring practitioners’ perspectives on BIM, especially their perspectives on main barriers and main advantages. To this end structured interviews were carried out based on questionnaires and with a range of different construction professionals. The results revealed that practitioners perceive improved communication and mitigated project risks by encouraged collaboration between project participants. However, it was also observed that the full implementation of BIM in the State of Kuwait requires concerted efforts to make clients demanding BIM, counteract resistance to change among construction professionals and offer more training for design team members. This paper forms part of an on-going research effort on BIM and its application in the State of Kuwait and it is on this basis that further research on the topic is proposed.

Keywords: building information modeling, BIM, construction industry, Kuwait

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Authors: Diana Gomez-Cano, J. C. Ochoa-Botero, Roberto Bernal Correa, Yhan Paul Arias

Abstract:

To obtain high mechanical performance, the fresh conditions of a mortar are decisive. Measuring the absorption of aggregates used in mortar mixes is a fundamental requirement for proper design of the mixes prior to their placement in construction sites. In this sense, absorption is a determining factor in the design of a mix because it conditions the amount of water, which in turn affects the water/cement ratio and the final porosity of the mortar. Thus, this work focuses on the mechanical behavior of recycled mortars manufactured from moisture correction using the Thermogravimetric Balancing Halogen Light (TBHL) technique in comparison with the traditional ASTM C 128 International Standard method. The advantages of using the TBHL technique are favorable in terms of reduced consumption of resources such as materials, energy, and time. The results show that in contrast to the ASTM C 128 method, the TBHL alternative technique allows obtaining a higher precision in the absorption values of recycled aggregates, which is reflected not only in a more efficient process in terms of sustainability in the characterization of construction materials but also in an effect on the mechanical performance of recycled mortars.

Keywords: alternative raw materials, halogen light, recycled mortar, resources optimization, water absorption

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Authors: Ana Paula Esteves, Diego S. Caetano, Louise L. B. Lomardo

Abstract:

This paper presents an approach on the advantages of using adequate coverage in the zenithal lighting typology in various areas of architectural production, while at the same time to encourage to the design concerns inherent in this choice of roofing in Brazil. Understanding that sustainability needs to cover several aspects, a roofing system such as zenithal lighting system can contribute to the provision of better quality natural light for the interior of the building, which is related to the good health and welfare; it will also be able to contribute for the sustainable aspects and environmental needs, when it allows the generation of energy in semitransparent or opacity photovoltaic solutions and economize the artificial lightning. When the energy balance in the building is positive, that is, when the building generates more energy than it consumes, it may fit into the Net Zero Energy Building concept. The zenithal lighting systems could be an important ally in Brazil, when solved the burden of heat gains, participate in the set of pro-efficiency actions in search of "zero energy buildings". The paper presents comparative three cases of buildings that have used this feature in search of better environmental performance, both in light comfort and sustainability as a whole. Two of these buildings are examples in Europe: the Notley Green School in the UK and the Isofóton factory in Spain. The third building with these principles of shed´s roof is located in Brazil: the Ipel´s factory in São Paulo.

Keywords: natural lighting, net zero energy building, sheds, semi-transparent photovoltaics

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Authors: Salami Ayobami Taofeek, Ajayi Adeola

Abstract:

Rural tourism entrepreurship is a tourist industry which revolutionizes businesses and prompting economic development across the globe. It encompasses huge range activities, natural or man-made attractions, amenities and facilities, transportation, marketing and information systems. It is also an important export for 83% of the developing countries and the main export for one third of them. In 2000, developing countries recorded 142.6 million international arrivals an increase of 95% compared to the figures of 1990. However, only developing countries with effective natural and man-made tourism supporting and enhancing infrastructure have been able to develop their tourism sector and seize the attendance advantages. Rural areas of Nigeria possess some distinctive peculiarities which can be transformed into attractive tourist centers. In spite of all these, rural tourism areas are still faced with myriad problems which include poor finance inadequate awareness and education, lack of progress in developing the rural of progress in developing the rural tourism potentials inadequate legislation, insecurity, entrepreneurial inertness, over-dependent on oil among others. This paper focuses on the impact and challenges of rural tourism entrepreneurship as strategy for economic development in Nigeria. It reviews literature rural tourism, tourism entrepreneurship potentials and classifications of Nigerians tourism potential’s destinations. The paper concludes that Nigeria Government should encourage rural based tourism entrepreneurship development by addressing the challenges facing rural tourism entrepreneurship in the country.

Keywords: entrepreneurship, economic development, rural tourism, tourism destinations tourism potentials

Procedia PDF Downloads 427