Search results for: semi-active variable friction dampers
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 2915

Search results for: semi-active variable friction dampers

1115 Offset Dependent Uniform Delay Mathematical Optimization Model for Signalized Traffic Network Using Differential Evolution Algorithm

Authors: Tahseen Saad, Halim Ceylan, Jonathan Weaver, Osman Nuri Çelik, Onur Gungor Sahin

Abstract:

A new concept of uniform delay offset dependent mathematical optimization problem is derived as the main objective for this study using a differential evolution algorithm. To control the coordination problem, which depends on offset selection and to estimate uniform delay based on the offset choice in a traffic signal network. The assumption is the periodic sinusoidal function for arrival and departure patterns. The cycle time is optimized at the entry links and the optimized value is used in the non-entry links as a common cycle time. The offset optimization algorithm is used to calculate the uniform delay at each link. The results are illustrated by using a case study and are compared with the canonical uniform delay model derived by Webster and the highway capacity manual’s model. The findings show new model minimizes the total uniform delay to almost half compared to conventional models. The mathematical objective function is robust. The algorithm convergence time is fast.

Keywords: area traffic control, traffic flow, differential evolution, sinusoidal periodic function, uniform delay, offset variable

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1114 A Review on Literatures in Management and Maintenance of WAQF Properties in Malaysia

Authors: Huraizah Arshad, Maizan Baba

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Malaysia is the country that consists of high population of Muslim community with more than 60%; as reported in year 2014. The stability of economy allowed people to contribute towards ongoing charity such as waqf and infaq. Waqf is an important component of the Islamic economic instruments since it is beneficial to help those needy in the community. Although waqf had been implemented in Malaysia for many years, there is no specific framework on how to manage and maintain the waqf properties in effective and efficient practice. Thus, a comprehensive framework related to the management and maintenance of the waqf properties is crucial to ensure that the administration of the fund is fair within the community. The objective of this article is to examine the related literatures in administration, management and maintenance of waqf for the past ten (10) years. The methodology of this article is through qualitative research based on literature on waqf administration and management; waqf planning and development and the application of maintenance concept. Data from each articles related in this field were collected and statistically analyzed using the SPSS software. A variable such as authorship patterns, number of articles published and geographical affiliation are identified in this study. The general finding in this article shows that there are still limited number of articles and papers published by the researchers related to this field. Henceforth, this article provides significant suggestions and strategies for the future research on waqf administration, management and maintenance.

Keywords: Waqf, administration and management, maintenance, improvement, facilities management

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1113 Potential of High Performance Ring Spinning Based on Superconducting Magnetic Bearing

Authors: M. Hossain, A. Abdkader, C. Cherif, A. Berger, M. Sparing, R. Hühne, L. Schultz, K. Nielsch

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Due to the best quality of yarn and the flexibility of the machine, the ring spinning process is the most widely used spinning method for short staple yarn production. However, the productivity of these machines is still much lower in comparison to other spinning systems such as rotor or air-jet spinning process. The main reason for this limitation lies on the twisting mechanism of the ring spinning process. In the ring/traveler twisting system, each rotation of the traveler along with the ring inserts twist in the yarn. The rotation of the traveler at higher speed includes strong frictional forces, which in turn generates heat. Different ring/traveler systems concerning with its geometries, material combinations and coatings have already been implemented to solve the frictional problem. However, such developments can neither completely solve the frictional problem nor increase the productivity. The friction free superconducting magnetic bearing (SMB) system can be a right alternative replacing the existing ring/traveler system. The unique concept of SMB bearings is that they possess a self-stabilizing behavior, i.e. they remain fully passive without any necessity for expensive position sensing and control. Within the framework of a research project funded by German research foundation (DFG), suitable concepts of the SMB-system have been designed, developed, and integrated as a twisting device of ring spinning replacing the existing ring/traveler system. With the help of the developed mathematical model and experimental investigation, the physical limitations of this innovative twisting device in the spinning process have been determined. The interaction among the parameters of the spinning process and the superconducting twisting element has been further evaluated, which derives the concrete information regarding the new spinning process. Moreover, the influence of the implemented SMB twisting system on the yarn quality has been analyzed with respect to different process parameters. The presented work reveals the enormous potential of the innovative twisting mechanism, so that the productivity of the ring spinning process especially in case of thermoplastic materials can be at least doubled for the first time in a hundred years. The SMB ring spinning tester has also been presented in the international fair “International Textile Machinery Association (ITMA) 2015”.

Keywords: ring spinning, superconducting magnetic bearing, yarn properties, productivity

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1112 Effective Medium Approximations for Modeling Ellipsometric Responses from Zinc Dialkyldithiophosphates (ZDDP) Tribofilms Formed on Sliding Surfaces

Authors: Maria Miranda-Medina, Sara Salopek, Andras Vernes, Martin Jech

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Sliding lubricated surfaces induce the formation of tribofilms that reduce friction, wear and prevent large-scale damage of contact parts. Engine oils and lubricants use antiwear and antioxidant additives such as zinc dialkyldithiophosphate (ZDDP) from where protective tribofilms are formed by degradation. The ZDDP tribofilms are described as a two-layer structure composed of inorganic polymer material. On the top surface, the long chain polyphosphate is a zinc phosphate and in the bulk, the short chain polyphosphate is a mixed Fe/Zn phosphate with a gradient concentration. The polyphosphate chains are partially adherent to steel surface through a sulfide and work as anti-wear pads. In this contribution, ZDDP tribofilms formed on gray cast iron surfaces are studied. The tribofilms were generated in a reciprocating sliding tribometer with a piston ring-cylinder liner configuration. Fully formulated oil of SAE grade 5W-30 was used as lubricant during two tests at 40Hz and 50Hz. For the estimation of the tribofilm thicknesses, spectroscopic ellipsometry was used due to its high accuracy and non-destructive nature. Ellipsometry works under an optical principle where the change in polarisation of light reflected by the surface, is associated with the refractive index of the surface material or to the thickness of the layer deposited on top. Ellipsometrical responses derived from tribofilms are modelled by effective medium approximation (EMA), which includes the refractive index of involved materials, homogeneity of the film and thickness. The materials composition was obtained from x-ray photoelectron spectroscopic studies, where the presence of ZDDP, O and C was confirmed. From EMA models it was concluded that tribofilms formed at 40 Hz are thicker and more homogeneous than the ones formed at 50 Hz. In addition, the refractive index of each material is mixed to derive an effective refractive index that describes the optical composition of the tribofilm and exhibits a maximum response in the UV range, being a characteristic of glassy semitransparent films.

Keywords: effective medium approximation, reciprocating sliding tribometer, spectroscopic ellipsometry, zinc dialkyldithiophosphate

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1111 Solving Transient Conduction and Radiation using Finite Volume Method

Authors: Ashok K. Satapathy, Prerana Nashine

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Radiative heat transfer in participating medium was anticipated using the finite volume method. The radiative transfer equations are formulated for absorbing and anisotropically scattering and emitting medium. The solution strategy is discussed and the conditions for computational stability are conferred. The equations have been solved for transient radiative medium and transient radiation incorporated with transient conduction. Results have been obtained for irradiation and corresponding heat fluxes for both the cases. The solutions can be used to conclude incident energy and surface heat flux. Transient solutions were obtained for a slab of heat conducting in slab by thermal radiation. The effect of heat conduction during the transient phase is to partially equalize the internal temperature distribution. The solution procedure provides accurate temperature distributions in these regions. A finite volume procedure with variable space and time increments is used to solve the transient energy equation. The medium in the enclosure absorbs, emits, and anisotropically scatters radiative energy. The incident radiations and the radiative heat fluxes are presented in graphical forms. The phase function anisotropy plays a significant role in the radiation heat transfer when the boundary condition is non-symmetric.

Keywords: participating media, finite volume method, radiation coupled with conduction, heat transfer

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1110 Genetic Determinants of Ovarian Response to Gonadotropin Stimulation in Women Undergoing Assisted Reproductive Treatment

Authors: D. Tohlob, E. Abo Hashem, N. Ghareeb, M. Ghanem, R. Elfarahaty, S. A. Roberts, P. Pemberton, L. Mohiyiddeen, W. G. Newman

Abstract:

Gonadotropin stimulation is used in females undergoing assisted reproductive treatment for ovulation induction, but ovarian response is variable and unpredictable in these women. More effective protocols and individualization of treatment are needed to increase the success rate of IVF/ICSI cycles. We genotyped seven variants reported in previous studies to be associated with ovarian response (number of ova retrieved and total gonadotropin dose) in women undergoing IVF treatment including FSHR variants Asn 680 Ser (c.2039 A > G), Thr 307 Ala (c. 919 > A), -29 G > A, HRG c.610 C > T gene, BMP15 -9 C > G, AMH Ile 49 Ser (c.146 G > T), and AMHR -489A˃G in 118 Egyptian females attending Mansoura Integrated Fertility Center in Egypt, these females were undergoing their first cycle of controlled ovarian hyper stimulation for IVF/ICSI treatment. They were analyzed by TaqMan allelic discrimination assay in Manchester Center of Genomic Medicine. We found no evidence of any significant difference (p value < 0.05) in the number of eggs retrieved or the gonadotropin dose used between individuals in all genotypes except for HRG c.610 C > T gene polymorphism where regression analysis gives a p value of 0.04 with a fewer eggs number in TT genotyped females. These results indicate that these variants do not provide sufficient clinically relevant data to individualize the treatment protocols.

Keywords: controlled ovarian hyperstimulation, gene variants, ovarian response, assisted reproduction

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1109 Breakfast Skipping and Health Status Among University Professionals in Bangladesh

Authors: Shatabdi Goon

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OBJECTIVE: To determine the prevalence and associations between breakfast skipping and health status for university professionals in Bangladesh. DESIGN: A cross-sectional descriptive study design was performed using information on respondent’s sociodemographic status and eating behavior. Factors associated with breakfast skipping were identified using multivariate regression models. SETTINGS: Data obtained from a representative sample (n 120) of university professionals randomly selected from two distinct universities in Dhaka city, Bangladesh. SUBJECT: A total number of one hundred and twenty university professionals with a mean age of 29 years. RESULT: Results indicated that approximately 35.8% of the sample skipped breakfast. Gender was the only statistically significant sociodemographic variable, with females skipping at over two times the rate of males (OR 95% CI: 1.9; 0.90-4.13). The reasons given for skipping breakfast were almost exclusively habit (39.5%), work pressure (23.2%) and lack of time (16.2%). Skippers were significantly more likely to be obese (OR 2.4; 95% CI 1.02- 5.7), less energetic (OR 3.5; 95% CI 1.5-8.6), associated with health problems (OR 4.3; 95% CI 1.8- 10.17) and eating tendency of fast food (OR 2.5; 95% CI 1.13 - 5.5). Gastric and heart burn (X2=4.19, p<0.05) and high blood pressure (X2=5.027, p<0.05) were detected among 34.9% and 27.9 % of those employees respectively identified as breakfast skippers and they showed significantly high prevalence. CONCLUSION: Breakfast skipping is highly prevalent among university professionals with significant association of different health problems in Bangladesh. Health promotion strategies should be used to encourage all adults to eat breakfast regularly.

Keywords: breakfast, healthy lifestyle, breakfast skipping, health status, university professionals

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1108 Alternative Acidizing Fluids and Their Impact on the Southern Algerian Shale Formations

Authors: Rezki Akkal, Mohamed Khodja, Slimane Azzi

Abstract:

Acidification is a technique used in oil reservoirs to improve annual production, reduce the skin and increase the pressure of an oil well while eliminating the formation damage that occurs during the drilling process, completion and, amongst others, to create new channels allowing the easy circulation of oil around a producing well. This is achieved by injecting an acidizing fluid at a relatively low pressure to prevent fracturing formation. The treatment fluid used depends on the type and nature of the reservoir rock traversed as well as its petrophysical properties. In order to understand the interaction mechanisms between the treatment fluids used for the reservoir rock acidizing, several candidate wells for stimulation were selected in the large Hassi Messaoud deposit in southern Algeria. The stimulation of these wells is completed using different fluids composed mainly of HCl acid with other additives such as corrosion inhibitors, clay stabilizers and iron controllers. These treatment fluids are injected over two phases, namely with clean tube (7.5% HCl) and matrix aidizing with HCl (15%). The stimulation results obtained are variable according to the type of rock traversed and its mineralogical composition. These results show that there has been an increase in production flow and head pressure respectively from 1.99 m3 / h to 3.56 m3 / h and from 13 Kgf / cm2 to 20 kgf / cm2 in the sands formation having good petrophysical properties of (porosity = 16%) and low amount of clay (Vsh = 6%).

Keywords: acidizing, Hassi-Messaoud reservoir, tube clean, matrix stimulation

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1107 Thermodynamics of Random Copolymers in Solution

Authors: Maria Bercea, Bernhard A. Wolf

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The thermodynamic behavior for solutions of poly (methyl methacrylate-ran-t-butyl methacrylate) of variable composition as compared with the corresponding homopolymers was investigated by light scattering measurements carried out for dilute solutions and vapor pressure measurements of concentrated solutions. The complex dependencies of the Flory Huggins interaction parameter on concentration and copolymer composition in solvents of different polarity (toluene and chloroform) can be understood by taking into account the ability of the polymers to rearrange in a response to changes in their molecular surrounding. A recent unified thermodynamic approach was used for modeling the experimental data, being able to describe the behavior of the different solutions by means of two adjustable parameters, one representing the effective number of solvent segments and another one accounting for the interactions between the components. Thus, it was investigated how the solvent quality changes with the composition of the copolymers through the Gibbs energy of mixing as a function of polymer concentration. The largest reduction of the Gibbs energy at a given composition of the system was observed for the best solvent. The present investigation proves that the new unified thermodynamic approach is a general concept applicable to homo- and copolymers, independent of the chain conformation or shape, molecular and chemical architecture of the components and of other dissimilarities, such as electrical charges.

Keywords: random copolymers, Flory Huggins interaction parameter, Gibbs energy of mixing, chemical architecture

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1106 SAR and B₁ Considerations for Multi-Nuclear RF Body Coils

Authors: Ria Forner

Abstract:

Introduction: Due to increases in the SNR at 7T and above, it becomes more favourable to make use of X-nuclear imaging. Integrated body coils tuned to 120MHz for 31P, 79MHz for 23Na, and 75 MHz for 13C at 7T were simulated with a human male, female, or child body model to assess strategies of use for metabolic MR imaging in the body. Methods: B1 and SAR efficiencies in the heart, liver, spleen, and kidneys were assessed using numerical simulations over the three frequencies with phase shimming. Results: B1+ efficiency is highly variable over the different organs, particularly for the highest frequency; however, local SAR efficiency remains relatively constant over the frequencies in all subjects. Although the optimal phase settings vary, one generic phase setting can be identified for each frequency at which the penalty in B1+ is at a max of 10%. Discussion: The simulations provide practical strategies for power optimization, B1 management, and maintaining safety. As expected, the B1 field is similar at 75MHz and 79MHz, but reduced at 120MHz. However, the B1 remains relatively constant when normalised by the square root of the peak local SAR. This is in contradiction to generalized SAR considerations of 1H MRI at different field strengths, which is defined by global SAR instead. Conclusion: Although the B1 decreases with frequency, SAR efficiency remains constant throughout the investigated frequency range. It is possible to shim the body coil to obtain a maximum of 10% extra B1+ in a specific organ in a body when compared to a generic setting.

Keywords: birdcage, multi-nuclear, B1 shimming, 7 Tesla MRI, liver, kidneys, heart, spleen

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1105 Inhibitory Effect of Potential Bacillus Probiotic Strains against Pathogenic Bacteria and Yeast Isolated from Oral Cavity

Authors: Fdhila Walid, Bayar Sihem, Khouidi Bochra, Maâtouk Fethi, Ben Amor Feten, Hajer Hentati, Mahdhi Abdelkarim

Abstract:

The presence of resistant bacteria in the oral cavity can be the major cause of dental antibiotic prophylaxis failure. Multidrug efflux has been described for many organisms, including bacteria and fungi as part of their drugs resistance strategy. The potential use of probiotic bacteria can be considered as a new alternative in the prevention or cure of oral cavity diseases. In this study, different Bacillus strains isolated from the environment were isolated and characterized using biochemical and molecular procedures. The inhibitory activity against different pathogenic bacteria and yeast strains was tested using diffusion agar assay method. Our data revealed that the tested strains have an antimicrobial effect against the pathogenic strains such as Streptococcus mutants. The inhibitory effect was variable depending from the probiotic and pathogenic strains. The obtained result demonstrated that Bacillus can be used as a potential candidates probiotic and help in the prevention and treatment of oral infections, including dental caries, periodontal disease and halitosis. Our data, partly encourage the use of probiotic strains because they do not produce acid which can contribute to faster installation decay and these are spore-forming bacteria that can withstand the stress of the oral cavity (acids, alkalis, and salty foods).

Keywords: probiotic, pathogenic bacteria, yeast, oral cavity

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1104 Effects of Fe Addition and Process Parameters on the Wear and Corrosion Characteristics of Icosahedral Al-Cu-Fe Coatings on Ti-6Al-4V Alloy

Authors: Olawale S. Fatoba, Stephen A. Akinlabi, Esther T. Akinlabi, Rezvan Gharehbaghi

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The performance of material surface under wear and corrosion environments cannot be fulfilled by the conventional surface modifications and coatings. Therefore, different industrial sectors need an alternative technique for enhanced surface properties. Titanium and its alloys possess poor tribological properties which limit their use in certain industries. This paper focuses on the effect of hybrid coatings Al-Cu-Fe on a grade five titanium alloy using laser metal deposition (LMD) process. Icosahedral Al-Cu-Fe as quasicrystals is a relatively new class of materials which exhibit unusual atomic structure and useful physical and chemical properties. A 3kW continuous wave ytterbium laser system (YLS) attached to a KUKA robot which controls the movement of the cladding process was utilized for the fabrication of the coatings. The titanium cladded surfaces were investigated for its hardness, corrosion and tribological behaviour at different laser processing conditions. The samples were cut to corrosion coupons, and immersed into 3.65% NaCl solution at 28oC using Electrochemical Impedance Spectroscopy (EIS) and Linear Polarization (LP) techniques. The cross-sectional view of the samples was analysed. It was found that the geometrical properties of the deposits such as width, height and the Heat Affected Zone (HAZ) of each sample remarkably increased with increasing laser power due to the laser-material interaction. It was observed that there are higher number of aluminum and titanium presented in the formation of the composite. The indentation testing reveals that for both scanning speed of 0.8 m/min and 1m/min, the mean hardness value decreases with increasing laser power. The low coefficient of friction, excellent wear resistance and high microhardness were attributed to the formation of hard intermetallic compounds (TiCu, Ti2Cu, Ti3Al, Al3Ti) produced through the in situ metallurgical reactions during the LMD process. The load-bearing capability of the substrate was improved due to the excellent wear resistance of the coatings. The cladded layer showed a uniform crack free surface due to optimized laser process parameters which led to the refinement of the coatings.

Keywords: Al-Cu-Fe coating, corrosion, intermetallics, laser metal deposition, Ti-6Al-4V alloy, wear resistance

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1103 Late Pleistocene Raised Coral Reefs in Rabigh Area, Red Sea: Microfacies and Environmental Interpretation

Authors: Ammar Manaa

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The late Pleistocene raised coral reef terraces, 1 to 5 m above present sea level, are distinguished in Rabigh area into two marine terraces at elevations 0.5 m and 3.20 m, in addition to back-reef facies. The lower and upper terraces consist mainly of corals that increased in abundance and distribution in the upper terrace, with a minor occurrence of detrital quartz and feldspar. The back-reef facies consist mainly of coralline algae with a minor occurrence of corals. The upper terrace was interpreted as a reef crest or algal ridge due to the dominance of bindstone facies. The lower terrace indicates an outer reef flat with the occurrence of grainstone and rudstone facies. The coral framework in the upper terrace indicates a low energy environment. Within the back-reef terrace, calcareous mud was dominant, which indicates low energy, lagoon environment. The XRD results for the studied terraces revealed a variable abundance of aragonite, high-Mg calcite, and low-Mg calcite, with a slight increase in calcite and high-Mg calcite in the upper terrace. The dominant diagenetic processes in the terraces are cementation by fibrous and blocky calcite and dissolution that varied slightly between the lower and upper terraces. This study provides a coral reef model relevant to a low energy system in a dry and hot environment.

Keywords: late Pleistocene, Rabigh, reef terraces, Red Sea, Saudi Arabia.

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1102 Comparing Failure Base Rates on the TOMM-1 and Rey-15 in Romanian and Canadian Disability Applicants

Authors: Iulia Crisan

Abstract:

Objective: The present study investigates the cross-cultural validity of three North-American performance validity indicators (PVTs) by comparing base rates of failure (BRF) in Romanian and Canadian disability applicants. Methods: Three PVTs (Test of Memory Malingering Trial 1 [TOMM-1], Rey Fifteen Item Test free recall [Rey-15 FR], and Rey FR+Recognition [Rey COMB]) were administered to a heterogeneous Romanian clinical sample (N Ro =54) and a similar Canadian sample (N Can = 52). Patients were referred for assessment to determine the severity of their cognitive deficits. Results: We compared the BRF in both samples at various cutoffs. BRF on TOMM-1 at ≤ 43 was similar (Ro = 33.3% vs. Can = 40.4%); at ≤40, Ro = 22.2% vs. Can = 25.0%. Likewise, comparable BRF were observed on Rey-15 FR at ≤ 8 (Ro = 7.4% vs. Can = 11.5%) and ≤ 11 (Ro = 27.8% vs. Can = 23.1%). However, the Romanian sample produced significantly higher failure rates on the Rey COMB at variable cutoffs (p <.05), possibly because Romanian patients were significantly older than the Canadian sample. Conclusion: Our findings offer proof of concept for the cross-cultural validity of the TOMM and Rey-15 FR. At the same time, they serve as a reminder that the generalizability of PVT cutoffs to different populations should not be assumed but verified empirically. Employing the TOMM as a criterion measure for newly developed PVTs is discussed.

Keywords: performance validity indicators, cross-cultural validity, failure base rates, clinical samples, cognitive dysfunction, TOMM-1, Rey-15, Rey COMB

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1101 Aerothermal Analysis of the Brazilian 14-X Hypersonic Aerospace Vehicle at Mach Number 7

Authors: Felipe J. Costa, João F. A. Martos, Ronaldo L. Cardoso, Israel S. Rêgo, Marco A. S. Minucci, Antonio C. Oliveira, Paulo G. P. Toro

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The Prof. Henry T. Nagamatsu Laboratory of Aerothermodynamics and Hypersonics, at the Institute for Advanced Studies designed the Brazilian 14-X Hypersonic Aerospace Vehicle, which is a technological demonstrator endowed with two innovative technologies: waverider technology, to obtain lift from conical shockwave during the hypersonic flight; and uses hypersonic airbreathing propulsion system called scramjet that is based on supersonic combustion, to perform flights on Earth's atmosphere at 30 km altitude at Mach numbers 7 and 10. The scramjet is an aeronautical engine without moving parts that promote compression and deceleration of freestream atmospheric air at the inlet through the conical/oblique shockwaves generated during the hypersonic flight. During high speed flight, the shock waves and the viscous forces yield the phenomenon called aerodynamic heating, where this physical meaning is the friction between the fluid filaments and the body or compression at the stagnation regions of the leading edge that converts the kinetic energy into heat within a thin layer of air which blankets the body. The temperature of this layer increases with the square of the speed. This high temperature is concentrated in the boundary-layer, where heat will flow readily from the boundary-layer to the hypersonic aerospace vehicle structure. Fay and Riddell and Eckert methods are applied to the stagnation point and to the flat plate segments in order to calculate the aerodynamic heating. On the understanding of the aerodynamic heating it is important to analyze the heat conduction transfer to the 14-X waverider internal structure. ANSYS Workbench software provides the Thermal Numerical Analysis, using Finite Element Method of the 14-X waverider unpowered scramjet at 30 km altitude at Mach number 7 and 10 in terms of temperature and heat flux. Finally, it is possible to verify if the internal temperature complies with the requirements for embedded systems, and, if is necessary to do modifications on the structure in terms of wall thickness and materials.

Keywords: aerodynamic heating, hypersonic, scramjet, thermal analysis

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1100 The Determinants of the Operational Performance in Airline Industry: A Case of a Turkish Airline Company

Authors: Mustafa K. Yilmaz, Ahmet Kaplan, Murat Guven, Vildan Kesici

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Aviation industry influences the social and economic growth across the countries. Further, airline companies are highly affected by social, political, and financial crises and show a high degree of cyclicity in operational performance. Hence, this paper investigates the effects of available seat kilometers (ASK), revenue per kilometer (RPK), passenger load factor (PLF) as well as socio-political crisis on the number of passengers carried (PC) by Turkish Airlines company over the period of 2010M1-2018M12. To conduct the analysis, we employ fully modified ordinary least squares (FMOLS), dynamic ordinary least squares (DOLS), and canonical cointegration regression (CCR) techniques using monthly data. We use ASK, RPK, PLF as independent variables to identify the determinants of the PC, as a dependent variable. We also test the effect of the socio-political crisis. The results reveal that there is a significant and negative relationship between ASK and PC, while the relationship between RPK and PC is positive and significant. We also find that there is an insignificant relationship between PLF and PC. Further, we also find a negative effect of the crisis on the PC. These findings show although the crisis had an immediate effect on the operational performance of Turkish Airlines, the company recovered from the crisis and cope with the situation very promptly. Thus, this proves the resilience and agile management ability of the company.

Keywords: airline industry, operational performance, air traffic, socio-political crisis

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1099 Transformation of Health Communication Literacy in Information Technology during Pandemic in 2019-2022

Authors: K. Y. S. Putri, Heri Fathurahman, Yuki Surisita, Widi Sagita, Kiki Dwi Arviani

Abstract:

Society needs the assistance of academics in understanding and being skilled in health communication literacy. Information technology runs very fast while health communication literacy skills in getting health communication information during the pandemic are not as fast as the development of information technology. The research question is whether there is an influence of health communication on information technology in health information during the pandemic in Indonesia. The purpose of the study is to find out the influence of health communication on information technology in health information during the pandemic in Indonesia. The concepts of health communication literacy and information technology are used this study. Previous research is in support of this study. Quantitative research methods by disseminating questionnaires in this study. The validity and reliability test of this study is positive, so it can proceed to the next statistical analysis. Descriptive results of variable health communication literacy are of positive value in all dimensions. All dimensions of information technology are of positive value. Statistical tests of the influence of health communication literacy on information technology are of great value. Discussion of both variables in the influence of health communication literacy and high-value information technology because health communication literacy has a high effect in information technology. Respondents to this study have high information technology skills. So that health communication literacy in obtaining health information during the 2019-2022 pandemic is needed. Research advice is that academics are still very much needed by the community in the development of society during the pandemic.

Keywords: health information, health information needs, literacy health communication, information technology

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1098 An Experimental Study to Mitigate Swelling Pressure of Expansive Tabuk Shale, Saudi Arabia

Authors: A. A. Embaby, A. Abu Halawa, M. Ramadan

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In Kingdom of Saudi Arabia, there are several areas where expansive soil exists in the form of variable-thicknesses layers in the developed regions. Severe distress to infrastructures can be caused by the development of heave and swelling pressure in this kind of expansive shale. Among the various techniques for expansive soil mitigation, the removal and replacement technique is very popular for lightly loaded structures and shallow foundations. This paper presents the result of an experimental study conducted for evaluating the effect of type and thickness of the cushion soils on mitigation of swelling characteristics of expanded shale. Seven undisturbed shale samples collected from Al Qadsiyah district, which is located in the Tabuk town north Kingdom of Saudi Arabia, are treated with two types of cushion coarse-grained sediments (CCS); sand and gravel. Each type is represented with three thicknesses, 22%, 33% and 44% in relation to the depth of the active zone. The test results indicated that the replacement of expansive shale by CCS reduces the swelling potential and pressure. It is found that the reduction in swelling depends on the type and thickness of CCS. The treatment by removing the original expansive shale and replacing it by cushion sand with 44% thickness reduced the swelling potential and pressure of about 53.29% and 62.78 %, respectively.

Keywords: cushion coarse-grained sediments (CCS), expansive soil, Saudi Arabia, swelling pressure, Tabuk Shale

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1097 Radiation Protection Study for the Assessment of Mixed Fields Ionizing Radiation

Authors: Avram Irina, Coiciu Eugenia-Mihaela, Popovici Mara-Georgiana, Mitu Iani Octavian

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ELI-NP stands as a cutting-edge facility globally, hosting unique radiological setups. It conducts experiments leveraging high-power lasers capable of producing extremely brief 10 PW pulses on two fronts. Moreover, it houses an exceptional gamma beam system with distinctive spectral characteristics. The facility hosts various experiments across designated experimental areas, encompassing ultra-short high-power laser tests, high-intensity gamma beam trials, and combined experiments utilizing both setups. The facility hosts a dosimetry laboratory, which recently obtained accreditation, where the radiation safety group employs a host of different types of detectors for monitoring the personnel, environment, and public exposure to ionizing radiation generated in experiments performed. ELI-NP's design was shaped by radiological protection assessments conducted through Monte Carlo simulations. The poster exemplifies an assessment conducted using the FLUKA code in an experimental area where a high-power laser system is implemented, and the future diagnostic system for variable energy gamma beams will soon be operational.

Keywords: radiation protection, Monte Carlo simulation, FLUKA, dosimetry

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1096 Optimization of Poly-β-Hydroxybutyrate Recovery from Bacillus Subtilis Using Solvent Extraction Process by Response Surface Methodology

Authors: Jayprakash Yadav, Nivedita Patra

Abstract:

Polyhydroxybutyrate (PHB) is an interesting material in the field of medical science, pharmaceutical industries, and tissue engineering because of its properties such as biodegradability, biocompatibility, hydrophobicity, and elasticity. PHB is naturally accumulated by several microbes in their cytoplasm during the metabolic process as energy reserve material. PHB can be extracted from cell biomass using halogenated hydrocarbons, chemicals, and enzymes. In this study, a cheaper and non-toxic solvent, acetone, was used for the extraction process. The different parameters like acetone percentage, and solvent pH, process temperature, and incubation periods were optimized using the Response Surface Methodology (RSM). RSM was performed and the determination coefficient (R2) value was found to be 0.8833 from the quadratic regression model with no significant lack of fit. The designed RSM model results indicated that the fitness of the response variable was significant (P-value < 0.0006) and satisfactory to denote the relationship between the responses in terms of PHB recovery and purity with respect to the values of independent variables. Optimum conditions for the maximum PHB recovery and purity were found to be solvent pH 7, extraction temperature - 43 °C, incubation time - 70 minutes, and percentage acetone – 30 % from this study. The maximum predicted PHB recovery was found to be 0.845 g/g biomass dry cell weight and the purity was found to be 97.23 % using the optimized conditions.

Keywords: acetone, PHB, RSM, halogenated hydrocarbons, extraction, bacillus subtilis.

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1095 A Fuzzy Inference Tool for Assessing Cancer Risk from Radiation Exposure

Authors: Bouharati Lokman, Bouharati Imen, Bouharati Khaoula, Bouharati Oussama, Bouharati Saddek

Abstract:

Ionizing radiation exposure is an established cancer risk factor. Compared to other common environmental carcinogens, it is relatively easy to determine organ-specific radiation dose and, as a result, radiation dose-response relationships tend to be highly quantified. Nevertheless, there can be considerable uncertainty about questions of radiation-related cancer risk as they apply to risk protection and public policy, and the interpretations of interested parties can differ from one person to another. Examples of tools used in the analysis of the risk of developing cancer due to radiation are characterized by uncertainty. These uncertainties are related to the history of exposure and different assumptions involved in the calculation. We believe that the results of statistical calculations are characterized by uncertainty and imprecision. Having regard to the physiological variation from one person to another. In this study, we develop a tool based on fuzzy logic inference. As fuzzy logic deals with imprecise and uncertain, its application in this area is adequate. We propose a fuzzy system with three input variables (age, sex and body attainable cancer). The output variable expresses the risk of infringement rate of each organ. A base rule is established from recorded actual data. After successful simulation, this will instantly predict the risk of infringement rate of each body following chronic exposure to 0.1 Gy.

Keywords: radiation exposure, cancer, modeling, fuzzy logic

Procedia PDF Downloads 295
1094 The Effect of Gamma rays on Physicochemical Properties of Carboxymethyl Starch

Authors: N. Rajeswara Rao, T. Venkatappa Rao, K. Sowri Babu, N. Srinivas Rao, P. S. V. Shanmukhi

Abstract:

Carboxymethyl Starch (CMS) is a biopolymer derived from starch by the substitution method. CMS is proclaimed to have improved physicochemical properties than native starch. The present work deals with the effect of gamma radiation on the physicochemical properties of CMS. The samples were exposed to gamma irradiation of doses 30, 60 and 90 kGy. The resultant properties were studied with electron spin resonance (ESR), fourier transform infrared spectrometer (FTIR), differential scanning calorimeter (DSC), X-ray diffractometer (XRD) and scanning electron microscopy. Irradiation of CMS by gamma rays initiates cleavage of glucosidic bonds producing different types of radicals. Some of these radicals convert to peroxy radicals by abstracting oxygen. The ESR spectrum of CMS is anisotropic and is thought to be due to the superposition of various component spectra. In order to analyze the ESR spectrum, computer simulations were also employed. ESR spectra are also recorded under different conditions like post-irradiation times, variable temperatures and saturation behavior in order to evaluate the stability of free radicals produced on irradiation. Thermal studies from DSC depict that for CMS the gelatization process was absconded at higher doses. Relative crystallinity was reduced significantly after irradiation from XRD Studies. FTIR studies also confirm the same aspect. From ESR studies, it was concluded that irradiated CMS could be a potential reference material in ESR dosimetry.

Keywords: gamma rays, free radicals, ESR simulations, gelatization

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1093 Application of the Total Least Squares Estimation Method for an Aircraft Aerodynamic Model Identification

Authors: Zaouche Mohamed, Amini Mohamed, Foughali Khaled, Aitkaid Souhila, Bouchiha Nihad Sarah

Abstract:

The aerodynamic coefficients are important in the evaluation of an aircraft performance and stability-control characteristics. These coefficients also can be used in the automatic flight control systems and mathematical model of flight simulator. The study of the aerodynamic aspect of flying systems is a reserved domain and inaccessible for the developers. Doing tests in a wind tunnel to extract aerodynamic forces and moments requires a specific and expensive means. Besides, the glaring lack of published documentation in this field of study makes the aerodynamic coefficients determination complicated. This work is devoted to the identification of an aerodynamic model, by using an aircraft in virtual simulated environment. We deal with the identification of the system, we present an environment framework based on Software In the Loop (SIL) methodology and we use MicrosoftTM Flight Simulator (FS-2004) as the environment for plane simulation. We propose The Total Least Squares Estimation technique (TLSE) to identify the aerodynamic parameters, which are unknown, variable, classified and used in the expression of the piloting law. In this paper, we define each aerodynamic coefficient as the mean of its numerical values. All other variations are considered as modeling uncertainties that will be compensated by the robustness of the piloting control.

Keywords: aircraft aerodynamic model, total least squares estimation, piloting the aircraft, robust control, Microsoft Flight Simulator, MQ-1 predator

Procedia PDF Downloads 269
1092 The Relationship between Knowledge Management Processes and Strategic Thinking at the Organization Level

Authors: Bahman Ghaderi, Hedayat Hosseini, Parviz Kafche

Abstract:

The role of knowledge management processes in achieving the strategic goals of organizations is crucial. To this end, understanding the relationship between knowledge management processes and different aspects of strategic thinking (followed by long-term organizational planning) should be considered. This research examines the relationship between each of the five knowledge management processes (creation, storage, transfer, audit, and deployment) with each dimension of strategic thinking (vision, creativity, thinking, communication and analysis) in one of the major sectors of the food industry in Iran. In this research, knowledge management and its dimensions (knowledge acquisition, knowledge storage, knowledge transfer, knowledge auditing, and finally knowledge utilization) as independent variables and strategic thinking and its dimensions (creativity, systematic thinking, vision, strategic analysis, and strategic communication) are considered as the dependent variable. The statistical population of this study consisted of 245 managers and employees of Minoo Food Industrial Group in Tehran. In this study, a simple random sampling method was used, and data were collected by a questionnaire designed by the research team. Data were analyzed using SPSS 21 software. LISERL software is also used for calculating and drawing models and graphs. Among the factors investigated in the present study, knowledge storage with 0.78 had the most effect, and knowledge transfer with 0.62 had the least effect on knowledge management and thus on strategic thinking.

Keywords: knowledge management, strategic thinking, knowledge management processes, food industry

Procedia PDF Downloads 156
1091 Flexural Properties of Carbon/Polypropylene Composites: Influence of Matrix Forming Polypropylene in Fiber, Powder, and Film States

Authors: Vijay Goud, Ramasamy Alagirusamy, Apurba Das, Dinesh Kalyanasundaram

Abstract:

Thermoplastic composites render new opportunities as effective processing technology while crafting newer complications into processing. One of the notable challenges is in achieving thorough wettability that is significantly deterred by the high viscosity of the long molecular chains of the thermoplastics. As a result of high viscosity, it is very difficult to impregnate the resin into a tightly interlaced textile structure to fill the voids present in the structure. One potential solution to the above problem, is to pre-deposit resin on the fiber, prior to consolidation. The current study compares DREF spinning, powder coating and film stacking methods of predeposition of resin onto fibers. An investigation into the flexural properties of unidirectional composites (UDC) produced from blending of carbon fiber and polypropylene (PP) matrix in varying forms of fiber, powder and film are reported. Dr. Ernst Fehrer (DREF) yarns or friction spun hybrid yarns were manufactured from PP fibers and carbon tows. The DREF yarns were consolidated to yield unidirectional composites (UDCs) referred to as UDC-D. PP in the form of powder was coated on carbon tows by electrostatic spray coating. The powder-coated towpregs were consolidated to form UDC-P. For the sake of comparison, a third UDC referred as UDC-F was manufactured by the consolidation of PP films stacked between carbon tows. The experiments were designed to yield a matching fiber volume fraction of about 50 % in all the three UDCs. A comparison of mechanical properties of the three composites was studied to understand the efficiency of matrix wetting and impregnation. Approximately 19% and 68% higher flexural strength were obtained for UDC-P than UDC-D and UDC-F respectively. Similarly, 25% and 81% higher modulus were observed in UDC-P than UDC-D and UDC-F respectively. Results from micro-computed tomography, scanning electron microscopy, and short beam tests indicate better impregnation of PP matrix in UDC-P obtained through electrostatic spray coating process and thereby higher flexural strength and modulus.

Keywords: DREF spinning, film stacking, flexural strength, powder coating, thermoplastic composite

Procedia PDF Downloads 212
1090 The Impact of Size of the Regional Economic Blocs to the Country’s Flows of Trade: Evidence from COMESA, EAC and Tanzania

Authors: Mosses E. Lufuke, Lorna M. Kamau

Abstract:

This paper attempted to assess whether the size of the regional economic bloc has an impact to the flow of trade to a particular country. Two different sized blocs (COMESA and EAC) and one country (Tanzania) have been used as the point of references. Using the results from of the analyses, the paper also was anticipated to establish whether it was rational for Tanzania to withdraw its membership from COMESA (the larger bloc) to join EAC (the small one). Gravity model has been used to estimate the relationship between the variables, from which the bilateral trade flows between Tanzania and the eighteen member countries of the two blocs (COMESA and EAC) was employed for the time between 2000 and 2013. In the model, the dummy variable for regional bloc (bloc) at which the Tanzania trade partner countries belong are also added to the model to understand which trade bloc exhibit higher trade flow with Tanzania. From the findings, it was noted that over the period of study (2000-2013) Tanzania acknowledged more than 257% of trade volume in EAC than in COMESA. Conclusive, it was noted that the flow of trade is explained by many other variables apart from the size of regional bloc; and that the size by itself offer insufficient evidence in causality relationship. The paper therefore remain neutral on such staggered switching decision since more analyses are required to establish the country’s trade flow, especially when if it had been in multiple membership of COMESA and EAC.

Keywords: economic bloc, flow of trade, size of bloc, switching

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1089 Machine Learning Analysis of Student Success in Introductory Calculus Based Physics I Course

Authors: Chandra Prayaga, Aaron Wade, Lakshmi Prayaga, Gopi Shankar Mallu

Abstract:

This paper presents the use of machine learning algorithms to predict the success of students in an introductory physics course. Data having 140 rows pertaining to the performance of two batches of students was used. The lack of sufficient data to train robust machine learning models was compensated for by generating synthetic data similar to the real data. CTGAN and CTGAN with Gaussian Copula (Gaussian) were used to generate synthetic data, with the real data as input. To check the similarity between the real data and each synthetic dataset, pair plots were made. The synthetic data was used to train machine learning models using the PyCaret package. For the CTGAN data, the Ada Boost Classifier (ADA) was found to be the ML model with the best fit, whereas the CTGAN with Gaussian Copula yielded Logistic Regression (LR) as the best model. Both models were then tested for accuracy with the real data. ROC-AUC analysis was performed for all the ten classes of the target variable (Grades A, A-, B+, B, B-, C+, C, C-, D, F). The ADA model with CTGAN data showed a mean AUC score of 0.4377, but the LR model with the Gaussian data showed a mean AUC score of 0.6149. ROC-AUC plots were obtained for each Grade value separately. The LR model with Gaussian data showed consistently better AUC scores compared to the ADA model with CTGAN data, except in two cases of the Grade value, C- and A-.

Keywords: machine learning, student success, physics course, grades, synthetic data, CTGAN, gaussian copula CTGAN

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1088 Comparing the Effectiveness of Social Skills Training and Stress Management on Self Esteem and Agression in First Grade Students of Iranian West High School

Authors: Hossein Nikandam Kermanshah, Babak Samavatian, Akbar Hemmati Sabet, Mohammad Ahmadpanah

Abstract:

This is a quasi-experimental study that has been conducted in order to compare the effectiveness of social skills training and stress management training on self-esteem and aggression in first grade high school students. Forty-five people were selected from research community and were put randomly in there groups of social skills training, stress management training and control ones. Collecting data tools in this study was devise, self-esteem and AGQ aggression questionnaire. Self-esteem and aggression questionnaires has been conducted as the pre-test and post-test. Social skills training and stress management groups participated in eight 1.5 hour session in a week. But control group did not receive any therapy. For descriptive analysis of data, statistical indicators like mean, standard deviation were used, and in inferential statistics level multi variable covariance analysis have been used. The finding result show that group training social skills and stress management is significantly effective on the self-esteem and aggression, there is a meaningful difference between training social skills and stress management on self-esteem that the preference is with group social skills training, in the difference between group social skills training and stress management on aggression, the preference is with group stress management.

Keywords: social skill training, stress management training, self-esteem aggression, psychological sciences

Procedia PDF Downloads 455
1087 Transcriptional Profiling of Developing Ovules in Litchi chinensis

Authors: Ashish Kumar Pathak, Ritika Sharma, Vishal Nath, Sudhir Pratap Singh, Rakesh Tuli

Abstract:

Litchi is a sub-tropical fruit crop with genotypes bearing delicious juicy fruits with variable seed size (bold to rudimentary size). Small seed size is a desirable trait in litchi, as it increases consumer acceptance and fruit processing. The biochemical activities in mid- stage ovules (e.g. 16, 20, 24 and 28 days after anthesis) determine the fate of seed and fruit development in litchi. Comprehensive ovule-specific transcriptome analysis was performed in two litchi genotypes with contrasting seed size to gain molecular insight on determinants of seed fates in litchi fruits. The transcriptomic data was de-novo assembled in 1,39,608 trinity transcripts, out of which 6,325 trinity transcripts were differentially expressed between the two contrasting genotypes. Differential transcriptional pattern was found among ovule development stages in contrasting litchi genotypes. The putative genes for salicylic acid, jasmonic acid and brassinosteroid pathway were down-regulated in ovules of small-seeded litchi. Embryogenesis, cell expansion, seed size and stress related trinity transcripts exhibited altered expression in small-seeded genotype. The putative regulators of seed maturation and seed storage were down-regulated in small-seed genotype.

Keywords: Litchi, seed, transcriptome, defence

Procedia PDF Downloads 226
1086 Quantitative Assessment of Soft Tissues by Statistical Analysis of Ultrasound Backscattered Signals

Authors: Da-Ming Huang, Ya-Ting Tsai, Shyh-Hau Wang

Abstract:

Ultrasound signals backscattered from the soft tissues are mainly depending on the size, density, distribution, and other elastic properties of scatterers in the interrogated sample volume. The quantitative analysis of ultrasonic backscattering is frequently implemented using the statistical approach due to that of backscattering signals tends to be with the nature of the random variable. Thus, the statistical analysis, such as Nakagami statistics, has been applied to characterize the density and distribution of scatterers of a sample. Yet, the accuracy of statistical analysis could be readily affected by the receiving signals associated with the nature of incident ultrasound wave and acoustical properties of samples. Thus, in the present study, efforts were made to explore such effects as the ultrasound operational modes and attenuation of biological tissue on the estimation of corresponding Nakagami statistical parameter (m parameter). In vitro measurements were performed from healthy and pathological fibrosis porcine livers using different single-element ultrasound transducers and duty cycles of incident tone burst ranging respectively from 3.5 to 7.5 MHz and 10 to 50%. Results demonstrated that the estimated m parameter tends to be sensitively affected by the use of ultrasound operational modes as well as the tissue attenuation. The healthy and pathological tissues may be characterized quantitatively by m parameter under fixed measurement conditions and proper calibration.

Keywords: ultrasound backscattering, statistical analysis, operational mode, attenuation

Procedia PDF Downloads 305