Search results for: molecular modeling

Authors: Yu-Hsi Huang, Ying-Der Tsai

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Piezoelectric circular plates can provide out-of-plane vibrational displacements on low frequency and in-plane vibrational displacements on high frequency. Piezoelectric semi-spherical shell, which is double-curvature structure, can induce three-dimensional vibrational displacements over a large frequency range. In this study, three-dimensional vibrational characteristics of piezoelectric semi-spherical shells with free boundary conditions are investigated using three experimental methods and finite element numerical modeling. For the experimental measurements, amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) is used to obtain resonant frequencies and radial and azimuthal mode shapes. This optical technique utilizes a full-field and non-contact optical system that measures both the natural frequency and corresponding vibration mode shape simultaneously in real time. The second experimental technique used, laser displacement meter is a point-wise displacement measurement method that determines the resonant frequencies of the piezoelectric shell. An impedance analyzer is used to determine the in-plane resonant frequencies of the piezoelectric semi-spherical shell. The experimental results of the resonant frequencies and mode shapes for the piezoelectric shell are verified with the result from finite element analysis. Excellent agreement between the experimental measurements and numerical calculation is presented on the three-dimensional vibrational characteristics of the piezoelectric semi-spherical shell.

Keywords: piezoelectric semi-spherical shell, mode shape, resonant frequency, electronic speckle pattern interferometry, radial vibration, azimuthal vibration

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Authors: Fang Liu, JunShuai Xue, JiaJia Yao, XueYan Yang, ZuMao Li, GuanLin Wu, HePeng Zhang, ZhiPeng Sun

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III-Nitride resonant tunneling diode (RTD) is one of the most promising candidates for multiple-valued logic (MVL) elements. Here, we report a monolithic integration of GaN resonant tunneling diodes to realize multiple negative differential resistance (NDR) regions for MVL application. GaN RTDs, composed of a 2 nm quantum well embedded in two 1 nm quantum barriers, are grown by plasma-assisted molecular beam epitaxy on free-standing c-plane GaN substrates. Negative differential resistance characteristic with a peak current density of 178 kA/cm² in conjunction with a peak-to-valley current ratio (PVCR) of 2.07 is observed. Statistical properties exhibit high consistency showing a peak current density standard deviation of almost 1%, laying the foundation for the monolithic integration. After complete electrical isolation, two diodes of the designed same area are connected in series. By solving the Poisson equation and Schrodinger equation in one dimension, the energy band structure is calculated to explain the transport mechanism of the differential negative resistance phenomenon. Resonant tunneling events in a sequence of the series-connected RTD pair (SCRTD) form multiple NDR regions with nearly equal peak current, obtaining three stable operating states corresponding to ternary logic. A frequency multiplier circuit achieved using this integration is demonstrated, attesting to the robustness of this multiple peaks feature. This article presents a monolithic integration of SCRTD with multiple NDR regions driven by the resonant tunneling mechanism, which can be applied to a multiple-valued logic field, promising a fast operation speed and a great reduction of circuit complexity and demonstrating a new solution for nitride devices to break through the limitations of binary logic.

Keywords: GaN resonant tunneling diode, multiple-valued logic system, frequency multiplier, negative differential resistance, peak-to-valley current ratio

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Authors: Seyed Hamed Hashemi Sohi, Gerald Jo Denoga

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Machining or metal cutting is one of the most widely used production processes in industry. The quality of the process and the resulting machined product depends on parameters like tool geometry, material, and cutting conditions. However, the relationships of these parameters to the cutting process are often based mostly on empirical knowledge. In this study, computer modeling and simulation using LS-DYNA software and a Smoothed Particle Hydrodynamic (SPH) methodology, was performed on the orthogonal metal cutting process to analyze three-dimensional deformation of AISI 1045 medium carbon steel during machining. The simulation was performed using the following constitutive models: the Power Law model, the Johnson-Cook model, and the Zerilli-Armstrong models (Z-A). The outcomes were compared against the simulated results obtained by Cenk Kiliçaslan using the Finite Element Method (FEM) and the empirical results of Jaspers and Filice. The analysis shows that the SPH method combined with the Zerilli-Armstrong constitutive model is a viable alternative to simulating the metal cutting process. The tangential force was overestimated by 7%, and the normal force was underestimated by 16% when compared with empirical values. The simulation values for flow stress versus strain at various temperatures were also validated against empirical values. The SPH method using the Z-A model has also proven to be robust against issues of time-scaling. Experimental work was also done to investigate the effects of friction, rake angle and tool tip radius on the simulation.

Keywords: metal cutting, smoothed particle hydrodynamics, constitutive models, experimental, cutting forces analyses

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Authors: Hashim Chunpir

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Support processes play an important role to facilitate researchers (users) to accomplish their research activities with the help of cyber-infrastructure(s). However, the current user-support process in cyber-infrastructure needs a feasible tool to support users. This tool must enable the users of a cyber-infrastructure to communicate efficiently with the staffs of a cyber-infrastructure in order to get technical and scientific assistance, whilst saving resources at the same time. This research paper narrates the real story of employing various forms of tools to support the user and staff communication. In addition, this paper projects the lessons learned from an exploration of the help-desk tools in the current state of user support process in Earth System Grid Federation (ESGF) from support staffs’ perspective. ESGF is a climate cyber-infrastructure that facilitates Earth System Modeling (ESM) and is taken as a case study in this paper. Finally, this study proposes a need for a tool, a framework or a platform that not only improves the user support process to address support servicing needs of end-users of e-Science infrastructures but also eases the life of staffs in providing assistance to the users. With the help of such a tool; the collaboration between users and the staffs of cyber-infrastructures is made easier. Consequently, the research activities of the users of e-Science infrastructure will thrive as the scientific and technical support will be available to users. Finally, this results into painless and productive e-Research.

Keywords: e-Science User Services, e-Research in Earth Sciences, Information Technology Services Management (ITSM), user support process, service desk, management of support activities, help desk tools, application of social media

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Authors: Fumihiro Ima, Shinichi Watanabe, Shingo Maeda, Haruna Imai, Hiroki Niimi

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It is important to know growth rate of brain tumors before surgery because it influences treatment planning including not only surgical resection strategy but also adjuvant therapy after surgery. Amide proton transfer (APT) imaging is an emerging molecular magnetic resonance imaging (MRI) technique based on chemical exchange saturation transfer without administration of contrast medium. The underlying assumption in APT imaging of tumors is that there is a close relationship between the proliferative activity of the tumor and mobile protein synthesis. We aimed to evaluate the diagnostic performance of APT imaging of pre-and post-treatment brain tumors. Ten patients with brain tumor underwent conventional and APT-weighted sequences on a 3.0 Tesla MRI before clinical intervention. The maximum and the minimum APT-weighted signals (APTWmax and APTWmin) in each solid tumor region were obtained and compared before and after clinical intervention. All surgical specimens were examined for histopathological diagnosis. Eight of ten patients underwent adjuvant therapy after surgery. Histopathological diagnosis was glioma in 7 patients (WHO grade 2 in 2 patients, WHO grade 3 in 3 patients and WHO grade 4 in 2 patients), meningioma WHO grade1 in 2 patients and primary lymphoma of the brain in 1 patient. High-grade gliomas showed significantly higher APTW-signals than that in low-grade gliomas. APTWmax in one huge parasagittal meningioma infiltrating into the skull bone was higher than that in glioma WHO grade 4. On the other hand, APTWmax in another convexity meningioma was the same as that in glioma WHO grade 3. Diagnosis of primary lymphoma of the brain was possible with APT imaging before pathological confirmation. APTW-signals in residual tumors decreased dramatically within one year after adjuvant therapy in all patients. APT imaging demonstrated excellent diagnostic performance for the planning of surgery and adjuvant therapy of brain tumors.

Keywords: amides, magnetic resonance imaging, brain tumors, cell proliferation

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Authors: Minhal Abidi, Moinuddin

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Diabetes mellitus (DM) induced metabolic abnormalities causes oxidative stress which leads to the pathogenesis of complications associated with diabetes like retinopathy, nephropathy periodontitis etc. Combination of glycation and oxidation 'glycoxidation' occurs when oxidative reactions affect the early state of glycation products. Low density lipoprotein (LDL) is prone to glycoxidative attack by sugars and methylglyoxal (MGO) being a strong glycating agent may have severe impact on its structure and consequent role in diabetes. Pro-inflammatory cytokines like IL1β and TNFα produced by the action of gram negative bacteria in periodontits (PD) can in turn lead to insulin resistance. This work discusses modifications to LDL as a result of glycoxidation. The changes in the protein molecule have been characterized by various physicochemical techniques and the immunogenicity of the modified molecules was also evaluated as they presented neo-epitopes. Binding of antibodies present in diabetes patients to the native and glycated LDL has been evaluated. Role of modified epitopes in the generation of antibodies in diabetes and periodontitis has been discussed. The structural perturbations induced in LDL were analyzed by UV–Vis, fluorescence, circular dichroism and FTIR spectroscopy, molecular docking studies, thermal denaturation studies, Thioflavin T assay, isothermal titration calorimetry, comet assay. MALDI-TOF, ketoamine moieties, carbonyl content and HMF content were also quantitated in native and glycated LDL. IL1β and TNFα levels were also measured in the type 2 DM and PD patients. We report increased carbonyl content, ketoamine moieties and HMF content in glycated LDL as compared to native analogue. The results substantiate that in hyperglycemic state MGO modification of LDL causes structural perturbations making the protein antigenic which could obstruct normal physiological functions and might contribute in the development of secondary complications in diabetic patients like periodontitis.

Keywords: advanced glycation end products, diabetes mellitus, glycation, glycoxidation, low density lipoprotein, periodontitis

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Authors: Ntokozo Dambuza, Maryna Van De Venter, Trevor Koekemoer

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Oxidative stress contributes to the pathogenesis of many diseases and consequently antioxidant therapy has attracted much attention as a potential therapeutic strategy. Regardless of the quantities ingested, antioxidants need to reach the diseased tissues at concentrations sufficient to combat oxidative stress. Bioavailability is thus a defining criterion for the therapeutic efficacy of antioxidants. In addition, therapeutic antioxidants must possess biologically relevant characteristics which can target the specific molecular mechanisms responsible for disease related oxidative stress. While many chemical antioxidant assays are available to quantify antioxidant capacity, they relate poorly to the biological environment and provide no information as to the bioavailability. The present comparative study thus aims to characterise green and fermented rooibos extracts, well recognized for their exceptional antioxidant capacity, in terms of antioxidant bioavailability and efficacy in a disease relevant cellular setting. Chinese green tea antioxidant activity was also evaluated. Chemical antioxidant assays (FRAP, DPPH and ORAC) confirmed the potent antioxidant capacity of both green and fermented rooibos, with green rooibos possessing antioxidant activity superior to that of fermented rooibos and Chinese green tea. Bioavailability was assessed using the PAMPA assay and the results indicate that green and fermented rooibos have a permeation coefficient of 5.7 x 10-6 and 6.9 x 10-6 cm/s, respectively. Chinese green tea permeability coefficient was 8.5 x 10-6 cm/s. These values were comparable to those of rifampicin, which is known to have a high permeability across intestinal epithelium with a permeability coefficient of 5 x 10 -6 cm/s. To assess the antioxidant efficacy in a cellular context, U937 and red blood cells were pre-treated with rooibos and Chinese green tea extracts in the presence of a dye DCFH-DA and then exposed to oxidative stress. Green rooibos exhibited highest activity with an IC50 value of 29 μg/ml and 70 μg/ml, when U937 and red blood cells were exposed oxidative stress, respectively. Fermented rooibos and Chinese green tea had IC50 values of 61 μg/ml and 57 μg/ml for U937, respectively, and 221 μg/ml and 405 μg/ml for red blood cells, respectively. These results indicate that fermented and green rooibos extracts were able to permeate the U937 cells and red blood cell membrane and inhibited oxidation of DCFH-DA to a fluorescent DCF within the cells.

Keywords: rooibos, antioxidants, permeability, bioavailability

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Authors: Inaam Nasrallah, Pascale Salameh, Abbas El-Outa, Assem Alkak, Rihab Nasr, Wafa Toufic Bawab

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Background: Hazardous Waste Management(HWM). is critical to human health outcomes and environmental protection. This study evaluated the knowledge regarding safety measures to be applied when collecting and storing waste in scientific laboratories of two universities in Lebanon.Method: A survey-based observational study was conducted in scientific laboratories of the public university and that of a private university, where a total of 309 participants were recruited.Result: The mean total knowledge score on safety measures of HWM was 9.02±4.34 (maximum attainable score, 13). Significant association (p<0.05) was found between knowledge score and job function, years of experience, educational level, professional status, work schedule, and training on proper HWM. Participants had adequate perceptions regarding the impact of HWM on health and the environment. Linear regression modeling revealed that knowledge score was significantly higher among bachelor level lab workers compared to those with doctoral degrees (p=0.043), full-time schedule workers versus part-timers (p=0.03), and among public university participants as compared to those of the private university (p<0.001).Conclusion: This study showed good knowledge concerning HWM in the scientific laboratoriesof the studied universities in Lebanon and a good awareness of the HWM on health and the environment. It highlights the importance of culture, attitude, and practice on proper HWM in the academic scientific laboratory.

Keywords: hasardous waste, safety measures, waste management, knwoledge score, scientific laboratory workers

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Authors: Masoud Mahdavi, Mojtaba Farzaneh Moghadam

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The seismic forces caused by the waves created in the depths of the earth during the earthquake hit the structure and cause the building to vibrate. Creating large seismic forces will cause low-strength sections in the structure to suffer extensive surface damage. The use of new steel shear walls in steel structures has caused the strength of the building and its main members (columns) to increase due to the reduction and depreciation of seismic forces during earthquakes. In the present study, an attempt was made to evaluate a type of steel shear wall that has regular holes in the inner sheet by modeling the finite element model with Abacus software. The shear wall of the steel plate, measuring 6000 × 3000 mm (one floor) and 3 mm thickness, was modeled with four different pores with a cross-sectional area. The shear wall was dynamically subjected to a time history of 5 seconds by three accelerators, El Centro, Imperial Valley and Kobe. The results showed that increasing the distance between the geometric center of the hole and the geometric center of the inner plate in the steel shear wall (increasing the R_CS index) caused the total maximum acceleration to be transferred from the perimeter of the hole to horizontal and vertical beams. The results also show that there is no direct relationship between R_CS index and total acceleration in steel shear wall and R_CS index is separate from the peak ground acceleration value of earthquake.

Keywords: hollow steel plate shear wall, time history analysis, finite element method, abaqus software

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Authors: P. Behera, K. K. Singh, D. K. Saini, M. De

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Implementation of 2D materials in the detection of bio analytes is highly advantageous in the field of sensing because of its high surface to volume ratio. We have designed our sensor array with different cationic two-dimensional MoS₂, where surface modification was achieved by cationic thiol ligands with different functionality. Green fluorescent protein (GFP) was chosen as signal transducers for its biocompatibility and anionic nature, which can bind to the cationic MoS₂ surface easily, followed by fluorescence quenching. The addition of bio-analyte to the sensor can decomplex the cationic MoS₂ and GFP conjugates, followed by the regeneration of GFP fluorescence. The fluorescence response pattern belongs to various analytes collected and transformed to linear discriminant analysis (LDA) for classification. At first, 15 different proteins having wide range of molecular weight and isoelectric points were successfully discriminated at 50 nM with detection limit of 1 nM. The sensor system was also executed in biofluids such as serum, where 10 different proteins at 2.5 μM were well separated. After successful discrimination of protein analytes, the sensor array was implemented for bacteria sensing. Six different bacteria were successfully classified at OD = 0.05 with a detection limit corresponding to OD = 0.005. The optimized sensor array was able to classify uropathogens from non-uropathogens in urine medium. Further, the technique was applied for discrimination of bacteria possessing resistance to different types and amounts of drugs. We found out the mechanism of sensing through optical and electrodynamic studies, which indicates the interaction between bacteria with the sensor system was mainly due to electrostatic force of interactions, but the separation of native bacteria from their drug resistant variant was due to Van der Waals forces. There are two ways bacteria can be detected, i.e., through bacterial cells and lysates. The bacterial lysates contain intracellular information and also safe to analysis as it does not contain live cells. Lysates of different drug resistant bacteria were patterned effectively from the native strain. From unknown sample analysis, we found that discrimination of bacterial cells is more sensitive than that of lysates. But the analyst can prefer bacterial lysates over live cells for safer analysis.

Keywords: array-based sensing, drug resistant bacteria, linear discriminant analysis, two-dimensional MoS₂

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Authors: Keyur Raval, Steffen Krohn, Bruno Moerschbacher

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Chitin, the biopolymer of the N-acetylglucosamine, is the most abundant biopolymer on the planet after cellulose. Industrially, chitin is isolated and purified from the shell residues of shrimps. A deacetylated derivative of chitin i.e. chitosan has more market value and applications owing to it solubility and overall cationic charge compared to the parent polymer. This deacetylation on an industrial scale is performed chemically using alkalis like sodium hydroxide. This reaction not only is hazardous to the environment owing to negative impact on the marine ecosystem. A greener option to this process is the enzymatic process. In nature, the naïve chitin is converted to chitosan by chitin deacetylase (CDA). This enzymatic conversion on the industrial scale is however hampered by the crystallinity of chitin. Thus, this enzymatic action requires the substrate i.e. chitin to be soluble which is technically difficult and an energy consuming process. We in this project wanted to address this shortcoming of CDA. In lieu of this, we have modeled a fusion protein with CDA and an auxiliary protein. The main interest being to increase the accessibility of the enzyme towards crystalline chitin. A similar fusion work with chitinases had improved the catalytic ability towards insoluble chitin. In the first step, suitable partners were searched through the protein data bank (PDB) wherein the domain architecture were sought. The next step was to create the models of the fused product using various in silico techniques. The models were created by MODELLER and evaluated for properties such as the energy or the impairment of the binding sites. A fusion PCR has been designed based on the linker sequences generated by MODELLER and would be tested for its activity towards insoluble chitin.

Keywords: chitin deacetylase, modeling, chitin binding domain, chitinases

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Authors: Siriraks Khawchaimaha, Sangwian Boonto

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Sport Authority of Thailand (SAT) is the state enterprise, promotes and supports all sports kind both professional and athletes for competitions, and administer under government policy and government officers and therefore, all financial supports whether cash inflows and cash outflows are strictly committed to government budget and limited to the planned projects at least 12 to 16 months ahead of reality, as results of ineffective in sport events, administration and competitions. In order to retain in the sports challenges around the world, SAT need to has its own sports business services model by each stadium, region and athletes’ competencies. Based on the HMK model of Khawchaimaha, S. (2007), this research study is formalized into each 10 regional stadiums to details into the characteristics root of fans, athletes, coaches, equipments and facilities, and stadiums. The research designed is firstly the evaluation of external factors: hardware whereby competition or practice of stadiums, playground, facilities, and equipments. Secondly, to understand the software of the organization structure, staffs and management, administrative model, rules and practices. In addition, budget allocation and budget administration with operating plan and expenditure plan. As results for the third step, issues and limitations which require action plan for further development and support, or to cease that unskilled sports kind. The final step, based on the HMK model and modeling canvas by Alexander O and Yves P (2010) are those of template generating Sports Business Services Model for each 10 SAT’s regional stadiums.

Keywords: HMK model, not for profit organization, sport business model, sport services model

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Authors: Juzhong Tan, William Kerr

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Conching is one critical procedure in chocolate processing, where special flavors are developed, and smooth mouse feel the texture of the chocolate is developed due to particle size reduction of cocoa mass and other additives. Therefore, determination of the particle size and volatile compounds profile of cocoa bean is important for chocolate manufacturers to ensure the quality of chocolate products. Currently, precise particle size measurement is usually done by laser scattering which is expensive and inaccessible to small/medium size chocolate manufacturers. Also, some other alternatives, such as micrometer and microscopy, can’t provide good measurements and provide little information. Volatile compounds analysis of cocoa during conching, has similar problems due to its high cost and limited accessibility. In this study, a self-made electronic nose system consists of gas sensors (TGS 800 and 2000 series) was inserted to a conching machine and was used to monitoring the volatile compound profile of chocolate during the conching. A model correlated volatile compounds profiles along with factors including the content of cocoa, sugar, and the temperature during the conching to particle size of chocolate particles by genetic programming was established. The model was used to predict the particle size reduction of chocolates with different cocoa mass to sugar ratio (1:2, 1:1, 1.5:1, 2:1) at 8 conching time (15min, 30min, 1h, 1.5h, 2h, 4h, 8h, and 24h). And the predictions were compared to laser scattering measurements of the same chocolate samples. 91.3% of the predictions were within the range of later scatting measurement ± 5% deviation. 99.3% were within the range of later scatting measurement ± 10% deviation.

Keywords: cocoa bean, conching, electronic nose, genetic programming

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Authors: Laura E. Monroe

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As more non-native English-speaking students enroll in English-medium universities, even more faculty will instruct students who are unprepared for the rigors of post-secondary academic writing in English. Many faculty members lack training and knowledge regarding the assessment of non-native English-speaking students’ writing, as well as the ability to provide effective feedback. This quantitative study investigated the possible attitudinal factors, including demographics, which might affect faculty preparedness and grading practices for both native and non-native English-speaking students’ academic writing and plagiarism, as well as the reasons faculty do not deduct points from both populations’ writing errors. Structural equation modeling and SPSS Statistics were employed to analyze the results of a faculty questionnaire disseminated to individuals who had taught non-native English-speaking students in academic subject courses. The findings from this study illustrated that faculty’s native language, years taught, and institution type were significant factors in not deducting points for academic writing errors and plagiarism, and the major reasons for not deducting points for errors were that faculty had too many students to grade, not enough training in assessing student written errors and plagiarism and that the errors and plagiarism would have taken too long to explain. The practical implications gleaned from these results can be applied to most departments in English-medium post-secondary institutions regarding faculty preparedness and training in student academic writing errors and plagiarism, and recommendations for future research are given for similar types of preparation and guidance for post-secondary faculty, regardless of degree path or academic subject.

Keywords: assessment, faculty, non-native English-speaking students, writing

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Authors: Sikander Nawaz Khan

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Natural disasters like flood, earthquake, cyclone, volcanic eruption and others are causing immense losses to the property and lives every year. Current status and actual loss information of natural hazards can be determined and also prediction for next probable disasters can be made using different remote sensing and mapping technologies. Global Positioning System (GPS) calculates the exact position of damage. It can also communicate with wireless sensor nodes embedded in potentially dangerous places. GPS provide precise and accurate locations and other related information like speed, track, direction and distance of target object to emergency responders. Remote Sensing facilitates to map damages without having physical contact with target area. Now with the addition of more remote sensing satellites and other advancements, early warning system is used very efficiently. Remote sensing is being used both at local and global scale. High Resolution Satellite Imagery (HRSI), airborne remote sensing and space-borne remote sensing is playing vital role in disaster management. Early on Geographic Information System (GIS) was used to collect, arrange, and map the spatial information but now it has capability to analyze spatial data. This analytical ability of GIS is the main cause of its adaption by different emergency services providers like police and ambulance service. Full potential of these so called 3S technologies cannot be used in alone. Integration of GPS and other remote sensing techniques with GIS has pointed new horizons in modeling of earth science activities. Many remote sensing cases including Asian Ocean Tsunami in 2004, Mount Mangart landslides and Pakistan-India earthquake in 2005 are described in this paper.

Keywords: disaster mitigation, GIS, GPS, remote sensing

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Authors: Mahfoodh Saleh Al Sabbagh, Amitabh Mishra, Anwar Al Sheyadi

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A tremendous transformation is taking place in the state of education in Sultanate of Oman. The vision 2040 for Higher Education focuses on both academic and technical sides of education aims at improving the quality of education as per higher international standards with emphasis on learning and innovation, creativity and scientific research. The objective is to achieve a proficient education system that keeps abreast of the recent development, the essentials of sustainable development and enhancing the national identity. Higher Education Institutes have contributed immensely to the growth of education in Oman, in this context; Business Organization represents the most complex social structure known today due to its dynamic nature. Employees are considered as one of the dynamic resources of the organization and through their commitment and involvement organization becomes competitive. Organization Culture can be promoted to facilitate the achievement of job satisfaction and employees commitment. The purpose of the research is to explore the impact of Higher Educational Institutions Culture on employee satisfaction, and commitment. Based on primary data, the study was conducted in Higher Education Institutions in the Sultanate of Oman. Data was collected through questionnaire consisting of 60 questions related to culture, satisfaction, and commitment. The sample consisted of 330 employees of leading Higher Education Institutes in the Sultanate of Oman. Structural Equation Modeling was carried out on the data through SPSS and AMOS. Results indicate that culture of organization is significantly related with employees’ satisfaction and commitment both in direct and indirect ways. Significant theoretical and practical implications are driven from the outcomes of the study.

Keywords: organization culture, employee satisfaction and commitment, higher education, Sultanate of Oman

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Authors: Monalisa Pal, Kalyan Mandal

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Herein we report the molecular functionalization of promising transition metal oxide nanostructures, such as Co3O4 nanocubes, using nontoxic and biocompati-ble organic ligand sodium tartrate. The electronic structural modification of the nanocubes imparted through functionalization and subsequent water solubilization reveals multiple absorption bands in the UV-vis region. Further surface modification of the solubilized nanocubes, leads to the emergence of intrinsic multi-color fluorescence (from blue, cyan, green to red region of the spectrum), upon excitation at proper wavelengths, where the respective excitation wavelengths have a direct correlation with the observed UV-vis absorption bands. Using a multitude of spectroscopic tools we have investigated the mechanistic insight behind the origin of different UV-vis absorption bands and emergence of multicolor photoluminescence from the functionalized nanocubes. Our detailed study shows that ligand to metal charge transfer (LMCT) from tartrate ligand to Co2+/Co3+ ions and d-d transitions involving Co2+/Co3+ ions are responsible for generation of this novel optical properties. Magnetic study reveals that, antiferromagnetic nature of Co3O4 nanocubes changes to ferromagnetic behavior upon functionalization, however, the overall magnetic response was very weak. To combine strong magnetism with this novel optical property, we followed the same surface modification strategy in case of CoFe2O4 nanoparticles, which reveals that irrespective of size and shape, all Co-based oxides can develop intrinsic multi-color fluorescence upon facile functionalization with sodium tartrate ligands and the magnetic response was significantly higher. Surface modified Co-based oxide nanostructures also show excellent catalytic activity in degradation of biologically and environmentally harmful dyes. We hope that, our developed facile functionalization strategy of Co-based oxides will open up new opportunities in the field of biomedical applications such as bio-imaging and targeted drug delivery.

Keywords: co-based oxide nanostructures, functionalization, multi-color fluorescence, catalysis

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Authors: Akbar Nawaz Khan, Abdul Ghaffar, Muhammad Naeem Riaz

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The study was conducted to investigate the phenotypic features, morphometry and production potentialities of indigenous naked neck chicken (NN) of Pakistan under intensive management condition. A total of 35 NN chicks were randomly selected, and the experiment was performed at Poultry and wildlife research section NARC Islamabad for a period of 22 weeks. The predominant plumage color was black and golden while skin color was observed white. The average shank length, leg length, thigh length, keel length, chest breadth, head width, wing space, wing length, body length, body girth, body height and pubic bone width in adult males and females were 69.19 ± 3.34mm, 117.93 ± 4.42mm, 117.93 ± 4.42mm, 90.87 ± 6.53mm, 95.03 ± 4.56mm, 49.77 ± 2.53mm, 30.63 ± 1.50cm, 27.24 ± 2.71cm, 18.88 ± 0.65cm, 17.77 ± 1.01cm, 25.96 ± 0.56cm, 47.81 ± 1.41cm and 35.69 ± 4.09mm respectively. The average age and live body weight of NN chicken at sexual maturity were recorded as 165.85 days and 1269.38 g. While hen-day egg production of NN was recorded as 45%. The present study was aimed to investigate the existence of polymorphism at IGF-I gene in indigenous naked neck chicken through PCR based Restriction Fragment Length Polymorphism. Based on restriction analysis using Hinf I restriction enzyme, three genotypes were detected designated as AA, AC, and CC. Restriction analysis of PCR amplified product showed the presence of DNA fragments of 622, 378, 244 and 191, (genotypes). The PCR-RFLP analysis is easy, cost effective method which permits the easy characterization of IGF-I gene. This showed the investigated IGF-I genes can serve as good molecular markers for marker assisted selection (MAS) concerning growth related traits in chicken.

Keywords: Desi chicken, naked neck, morphology, morphometry, production potential, egg traits, egg geometry, IGF-I, growth, PCR- RFLP, chicken

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Authors: Khaled Alshamari

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Synthesized partially phosphorylated polyvinyl phosphate derivative (PPVP) was functionalized to extract Zirconium (IV) from Egyptian zircon sand. The specifications for the PPVP composite were approved effectively via different techniques, namely, FT-IR, XPS, BET, EDX, TGA, HNMR, C-NMR, GC-MS, XRD and ICP-OES analyses, which demonstrated a satisfactory synthesis of PPVP and zircon dissolution from Egyptian zircon sand. Factors controlling parameters, such as pH values, shaking time, initial zirconium concentration, PPVP dose, nitrate ions concentration, co-ions, temperature and eluting agents, have been optimized. At 25 ◦C, pH 0, 20 min shaking, 0.05 mol/L zirconium ions and 0.5 mol/L nitrate ions, PPVP has an exciting preservation potential of 195 mg/g, equivalent to 390 mg/L zirconium ions. From the extraction–distribution isotherm, the practical outcomes of Langmuir’s modeling are better than the Freundlich model, with a theoretical value of 196.07 mg/g, which is more in line with the experimental results of 195 mg/g. The zirconium ions adsorption onto the PPVP composite follows the pseudo-second-order kinetics with a theoretical capacity value of 204.08 mg/g. According to thermodynamic potential, the extraction process was expected to be an exothermic, spontaneous and beneficial extraction at low temperatures. The thermodynamic parameters ∆S (−0.03 kJ/mol), ∆H (−12.22 kJ/mol) and ∆G were also considered. As the temperature grows, ∆G values increase from −2.948 kJ/mol at 298 K to −1.941 kJ/mol at 338 K. Zirconium ions may be eluted from the working loaded PPVP by 0.025M HNO₃, with a 99% efficiency rate. It was found that zirconium ions revealed good separation factors towards some co-ions such as Hf⁴+ (28.82), Fe³+ (10.64), Ti⁴+ (28.82), V⁵+ (86.46) and U⁶+ (68.17). A successful alkali fusion technique with NaOH flux followed by the extraction with PPVP is used to obtain a high-purity zirconia concentrate with a zircon content of 72.77 % and a purity of 98.29%. As a result of this, the improved factors could finally be used.

Keywords: zirconium extraction, partially phosphorylated polyvinyl phosphate (PPVP), acidic medium, zircon

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Authors: Pius Babuna, Xiaohua Yang, Roberto Xavier Supe Tulcan, Bian Dehui, Mohammed Takase, Bismarck Yelfogle Guba, Chuanliang Han, Doris Abra Awudi, Meishui Lia

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Water inequality, water security, and water governance are fundamental parameters that affect the sustainable use of water resources. Through policy formulation and decision-making, water governance determines both water security and water inequality. Largely, where water inequality exists, water security is undermined through unsustainable water use practices that lead to pollution of water resources, conflicts, hoarding of water, and poor sanitation. Incidentally, the interconnectedness of water governance, water inequality, and water security has not been investigated previously. This study modified the Gini coefficient and used a Logistics Growth of Water Resources (LGWR) Model to access water inequality and water security mathematically, and discussed the connected role of water governance. We tested the validity of both models by calculating the actual water inequality and water security of Ghana. We also discussed the implications of water inequality on water security and the overarching role of water governance. The results show that regional water inequality is widespread in some parts. The Volta region showed the highest water inequality (Gini index of 0.58), while the central region showed the lowest (Gini index of 0.15). Water security is moderately sustainable. The use of water resources is currently stress-free. It was estimated to maintain such status until 2132 ± 18, when Ghana will consume half of the current total water resources of 53.2 billion cubic meters. Effectively, water inequality is a threat to water security, results in poverty, under-development heightens tensions in water use, and causes instability. With proper water governance, water inequality can be eliminated through formulating and implementing approaches that engender equal allocation and sustainable use of water resources.

Keywords: water inequality, water security, water governance, Gini coefficient, moran index, water resources management

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Authors: Saurabh B. Ganorkar, Atul A. Shirkhedkar

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The need for investigations protecting against toxic impurities though seems to be a primary requirement; the impurities which may prove non - toxic can be explored for their therapeutic potential if any to assist advanced drug discovery. The essential role of pharmaceutical analysis can thus be extended effectively to achieve it. The present study successfully achieved these objectives with characterization of major degradation products as impurities for Zileuton which has been used for to treat asthma since years. The forced degradation studies were performed to identify the potential degradation products using Ultra-fine Liquid-chromatography. Liquid-chromatography-Mass spectrometry (Time of Flight) and Proton Nuclear Magnetic Resonance Studies were utilized effectively to characterize the drug along with five major oxidative and hydrolytic degradation products (DP’s). The mass fragments were identified for Zileuton and path for the degradation was investigated. The characterized DP’s were subjected to In-Silico studies as XP Molecular Docking to compare the gain or loss in binding affinity with 5-Lipooxygenase enzyme. One of the impurity of was found to have the binding affinity more than the drug itself indicating for its potential to be more bioactive as better Antiasthmatic. The close structural resemblance has the ability to potentiate or reduce bioactivity and or toxicity. The chances of being active biologically at other sites cannot be denied and the same is achieved to some extent by predictions for probability of being active with Prediction of Activity Spectrum for Substances (PASS) The impurities found to be bio-active as Antineoplastic, Antiallergic, and inhibitors of Complement Factor D. The toxicological abilities as Ames-Mutagenicity, Carcinogenicity, Developmental Toxicity and Skin Irritancy were evaluated using Toxicity Prediction by Komputer Assisted Technology (TOPKAT). Two of the impurities were found to be non-toxic as compared to original drug Zileuton. As the drugs are purposed and repurposed effectively the impurities can also be; as they can have more binding affinity; less toxicity and better ability to be bio-active at other biological targets.

Keywords: UFLC, LC-MS-TOF, NMR, Zileuton, impurities, toxicity, bio-activity

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Authors: Kazeem Adesina Dauda, Waheed Babatunde Yahya

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To design a tree that maximizes within-node homogeneity, there is a need for a homogeneity measure that is appropriate for event history data with multiple risks. We consider the use of Deviance and Modified Cox-Snell residuals as a measure of impurity in Classification Regression Tree (CART) and compare our results with the results of Fiona (2008) in which homogeneity measures were based on Martingale Residual. Data structure approach was used to validate the performance of our proposed techniques via simulation and real life data. The results of univariate competing risk revealed that: using Deviance and Cox-Snell residuals as a response in within node homogeneity classification tree perform better than using other residuals irrespective of performance techniques. Bone marrow transplant data and double-blinded randomized clinical trial, conducted in other to compare two treatments for patients with prostate cancer were used to demonstrate the efficiency of our proposed method vis-à-vis the existing ones. Results from empirical studies of the bone marrow transplant data showed that the proposed model with Cox-Snell residual (Deviance=16.6498) performs better than both the Martingale residual (deviance=160.3592) and Deviance residual (Deviance=556.8822) in both event of interest and competing risks. Additionally, results from prostate cancer also reveal the performance of proposed model over the existing one in both causes, interestingly, Cox-Snell residual (MSE=0.01783563) outfit both the Martingale residual (MSE=0.1853148) and Deviance residual (MSE=0.8043366). Moreover, these results validate those obtained from the Monte-Carlo studies.

Keywords: within-node homogeneity, Martingale residual, modified Cox-Snell residual, classification and regression tree

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Authors: Mohsin Raza, Rizwan Latif, Syed Adnan Qasim, Imran Shafi

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High torque low-speed diesel engine has a wide range of industrial and commercial applications. In literature, it’s found that lot of work has been done for the high-speed diesel engine and research on High Torque low-speed is rare. The fuel injection plays a key role in the efficiency of engine and reduction in exhaust emission. The fuel breakup plays a critical role in air-fuel mixture and spray combustion. The current study explains numerically an important phenomenon in spray combustion which is deformation and breakup of liquid drops in compression ignition internal combustion engine. The secondary breakup and its influence on spray and characteristics of compressed gas in-cylinder have been calculated by using simulation software in the backdrop of high torque low-speed diesel like conditions. The secondary spray breakup is modeled with KH - RT instabilities. The continuous field is described by turbulence model and dynamics of the dispersed droplet is modeled by Lagrangian tracking scheme. The results by using KH - RT model are compared against other default methods in OpenFOAM and published experimental data from research and implemented in CFD (Computational Fluid Dynamics). These numerical simulation, done in OpenFoam and Matlab, results are analyzed for the complete 720- degree 4 stroke engine cycle at a low engine speed, for favorable agreement to be achieved. Results thus obtained will be analyzed for better evaporation in near nozzle region. The proposed analyses will further help in better engine efficiency, low emission and improved fuel economy.

Keywords: diesel fuel, KH-RT, Lagrangian , Open FOAM, secondary breakup

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Authors: Lynn Louis, Bor Shin Chee, Marion McAfee, Michael Nugent

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This article aims to develop a sustained release formulation of microspheres containing the mTOR inhibitor Everolimus (EVR) using Polyvinyl alcohol (PVA) to enhance the bioavailability of the drug and to overcome poor solubility characteristics of Everolimus. This paper builds on recent work in the manufacture of microspheres using the sessile droplet technique by freezing the polymer-drug solution by suspending the droplets into pre-cooled ethanol vials immersed in liquid nitrogen. The spheres were subjected to 6 freezing cycles and 3 freezing cycles with thawing to obtain proper geometry, prevent aggregation, and achieve physical cross-linking. The prepared microspheres were characterised for surface morphology by SEM, where a 3-D porous structure was observed. The in vitro release studies showed a 62.17% release over 12.5 days, indicating a sustained release due to good encapsulation. This result is comparatively much more than the 49.06% release achieved within 4 hours from the solvent cast Everolimus film as a control with no freeze-thaw cycles performed. The solvent cast films were made in this work for comparison. A prolonged release of Everolimus using a polymer-based drug delivery system is essential to reach optimal therapeutic concentrations in treating SEGA tumours without systemic exposure. These results suggest that the combination of PVA and Everolimus via a rheological synergism enhanced the bioavailability of the hydrophobic drug Everolimus. Physical-chemical characterisation using DSC and FTIR analysis showed compatibility of the drug with the polymer, and the stability of the drug was maintained owing to the high molecular weight of the PVA. The obtained results indicate that the developed PVA/EVR microsphere is highly suitable as a potential drug delivery system with improved bioavailability in treating Subependymal Giant cell astrocytoma (SEGA).

Keywords: drug delivery system, everolimus, freeze-thaw cycles, polyvinyl alcohol

Procedia PDF Downloads 92

Authors: Fumihiro Imai, Shinichi Watanabe, Shingo Maeda, Haruna Imai, Hiroki Niimi

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It is important to know the growth rate of brain tumors before surgery because it influences treatment planning, including not only surgical resection strategy but also adjuvant therapy after surgery. Amide proton transfer (APT) imaging is an emerging molecular magnetic resonance imaging (MRI) technique based on chemical exchange saturation transfer without the administration of a contrast medium. The underlying assumption in APT imaging of tumors is that there is a close relationship between the proliferative activity of the tumor and mobile protein synthesis. We aimed to evaluate the diagnostic performance of APT imaging of pre-and post-treatment brain tumors. Ten patients with brain tumor underwent conventional and APT-weighted sequences on a 3.0 Tesla MRI before clinical intervention. The maximum and the minimum APT-weighted signals (APTWmax and APTWmin) in each solid tumor region were obtained and compared before and after a clinical intervention. All surgical specimens were examined for histopathological diagnosis. Eight of ten patients underwent adjuvant therapy after surgery. Histopathological diagnosis was glioma in 7 patients (WHO grade 2 in 2 patients, WHO grade 3 in 3 patients, and WHO grade 4 in 2 patients), meningioma WHO grade 1 in 2 patients, and primary lymphoma of the brain in 1 patient. High-grade gliomas showed significantly higher APTW signals than that low-grade gliomas. APTWmax in one huge parasagittal meningioma infiltrating into the skull bone was higher than that in glioma WHO grade 4. On the other hand, APTWmax in another convexity meningioma was the same as that in glioma WHO grade 3. Diagnosis of primary lymphoma of the brain was possible with APT imaging before pathological confirmation. APTW signals in residual tumors decreased dramatically within one year after adjuvant therapy in all patients. APT imaging demonstrated excellent diagnostic performance for the planning of surgery and adjuvant therapy of brain tumors.

Keywords: amides, magnetic resonance imaging, brain tumors, cell proliferation

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Authors: Mourad Bédir, Sami Khomsi, Hakim Gabtni, Hajer Azaiez, Ramzi Gharsalli, Riadh Chebbi

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Eastern Tunisia is a semi-arid area; located in the northern Africa plate; southern Mediterranean side. It is facing water scarcity, overexploitation, and decreasing of water quality of phreatic water table. Water supply and storage will not respond to the demographic and economic growth and demand. In addition, only 5 109 m3 of rainwater from 35 109 m3 per year renewable rain water supply can be retained and remobilized. To remediate this water deficiency, researches had been focused to near new subsurface deep aquifers resources. Among them, Upper Miocene sandstone deposits of Béglia, Saouaf, and Somaa Formations. These sandstones are known for their proven Hydrogeologic and hydrocarbon reservoir characteristics in the Tunisian margin. They represent semi-confined to confined aquifers. This work is based on new integrated approaches of seismic stratigraphy, seismic tectonics, and hydrogeology, to highlight and characterize these reservoirs levels for aquifer exploitation in semi-arid area. As a result, five to six third order sequence deposits had been highlighted. They are composed of multi-layered extended sandstones reservoirs; separated by shales packages. These reservoir deposits represent lowstand and highstand system tracts of these sequences, which represent lowstand and highstand system tracts of these sequences. They constitute important strategic water resources volumes for the region.

Keywords: Tunisia, Hydrogeology, sandstones, basin, seismic, aquifers, modeling

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Authors: Jiangxia Han, Liang Xue, Keda Chen

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Despite the significant progress over the last decades in reservoir simulation using numerical discretization, meshing is complex. Moreover, the high degree of freedom of the space-time flow field makes the solution process very time-consuming. Therefore, we present Physics-Informed Convolutional Neural Networks(PICNN) as a hybrid scientific theory and data method for reservoir modeling. Besides labeled data, the model is driven by the scientific theories of the underlying problem, such as governing equations, boundary conditions, and initial conditions. PICNN integrates governing equations and boundary conditions into the network architecture in the form of a customized convolution kernel. The loss function is composed of data matching, initial conditions, and other measurable prior knowledge. By customizing the convolution kernel and minimizing the loss function, the neural network parameters not only fit the data but also honor the governing equation. The PICNN provides a methodology to model and history-match flow and transport problems in porous media. Numerical results demonstrate that the proposed PICNN can provide an accurate physical solution from a limited dataset. We show how this method can be applied in the context of a forward simulation for continuous problems. Furthermore, several complex scenarios are tested, including the existence of data noise, different work schedules, and different good patterns.

Keywords: convolutional neural networks, deep learning, flow and transport in porous media, physics-informed neural networks, reservoir simulation

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Authors: Suliman Al Balawi

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Food waste is a significant problem in the Kingdom of Saudi Arabia (KSA). About SR13 billion worth of food is wasted per year in the KSA. From moral, social, and economic perspectives, it is essential to reduce the wastage of food. Although studies have identified the amount of food waste in the KSA, there is a lack of research on why people in the KSA waste food; thus, it is difficult to design efficient intervention programs to reduce food waste. This research investigates the key factors that influence the food waste behavior of the people of the KSA. A food waste behavior model is proposed in this study that has moral disengagement at the center of the model. Following a literature survey, it is hypothesised that religiosity, hedonic value, frugality, and trait cynicism are the antecedents of moral disengagement that are likely to impact the food waste behavior of the people of the KSA. The study further posits that an intervention strategy in the form of a social marketing campaign that focuses on lowering the level of moral disengagement could reduce the food waste behavior of the people of the KSA. This study will apply a pre-test/post-test experimental design (control group). A random sampling method will be used to select participants from the (employees of a chosen firm) in the KSA. The social marketing campaign will be run for six months through the Corporate Social Responsibility Department of the Company, and to analyse the experimental data, structural equation modeling (SEM) will be used. The outcomes of the study will demonstrate the effectiveness of a social marketing campaign for improving the food waste behavior of the people of the KSA and will ultimately lay the foundation for designing efficient intervention programs in the future. This study will contribute to the knowledge on food waste behavior by testing a newly proposed food waste behavior model in the KSA.

Keywords: food waste, social marketing, Saudi Arabia, moral disengagement

Procedia PDF Downloads 155

Authors: Javier Navarro Garcia, Narciso Vazquez Carretero

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Eurocode 1, part 1-4, wind actions, includes in its article 1.5 the possibility of using numerical calculation methods to obtain information on the loads acting on a building. On the other hand, the analysis using computational fluids dynamics (CFD) in aerospace, aeronautical, and industrial applications is already in widespread use. The application of techniques based on CFD analysis on the building to study its aerodynamic behavior now opens a whole alternative field of possibilities for civil engineering and architecture; optimization of the results with respect to those obtained by applying the regulations, the possibility of obtaining information on pressures, speeds at any point of the model for each moment, the analysis of turbulence and the possibility of modeling any geometry or configuration. The present work compares the results obtained on a building, with respect to its aerodynamic behavior, from a mathematical model based on the analysis by CFD with the results obtained by applying Eurocode1, part1-4, wind actions. It is verified that the results obtained by CFD techniques suppose an optimization of the wind action that acts on the building with respect to the wind action obtained by applying the Eurocode1, part 1-4, wind actions. In order to carry out this verification, a 45m high square base truncated pyramid building has been taken. The mathematical model on CFD, based on finite volumes, has been calculated using the FLUENT commercial computer application using a scale-resolving simulation (SRS) type large eddy simulation (LES) turbulence model for an atmospheric boundary layer wind with turbulent component in the direction of the flow.

Keywords: aerodynamic, CFD, computacional fluids dynamics, computational mechanics

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Authors: Shalini Arora, Sri Sivakumar

Abstract:

The deep removal of high molecular weight sulphur compounds (e.g., 4,6, dimethyl dibenzothiophene) is challenging due to their steric hindrance. Hydrogenation desulfurization (HYD) pathway is the main pathway to remove these sulfur compounds, and it is mainly governed by the number of type 2 sites. The formation of type 2 sites can be enhanced by modulating the pore structure and the interaction between the active metal and support. To this end, we report the enhanced HDS catalytic activity of ultrasmall NiMo supported on amorphous alumina (A-Al₂O₃) catalysts by one pot colloidal synthesis method followed by calcination and sulfidation. The amorphous alumina (A-Al₂O₃) was chosen as the support due to its lower surface energy, better physicochemical properties, and enhanced acidic sites (due to the dominance of tetra and penta coordinated [Al] sites) than crystalline alumina phase. At 20% metal oxide composition, NiMo supported on A-Al₂O₃ catalyst showed 1.4 and 1.2 times more reaction rate constant and turn over frequency (TOF) respectively than the conventional catalyst (wet impregnated NiMo catalysts) for HDS reaction of dibenzothiophene reactant molecule. A-Al₂O₃ supported catalysts represented enhanced type 2 sites formation (because this catalystpossesses higher sulfidation degree (80%) and NiMoS sites (19.3 x 10¹⁷ sites/mg) with desired optimum stacking degree (2.5) than wet impregnated catalyst at same metal oxide composition 20%) along with higher active metal dispersion, Mo edge site fraction. The experimental observations were also supported by DFT simulations. Lower heat of adsorption (< 4.2 ev for MoS2 interaction and < 3.15 ev for Ni doped MoS2 interaction) values for A-Al₂O₃ confirmed the presence of weaker metal-support interaction in A-Al₂O₃ in contrast to crystalline ℽ-Al₂O3. The weak metal-support interaction for prepared catalysts clearly suggests the higher formation of type 2 sites which leads to higher catalytic activity for HDS reaction.

Keywords: amorphous alumina, colloidal, desulfurization, metal-support interaction

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