Search results for: exponential stability in probability

Authors: Dana Madalina Pohrib, Elena Irina Ciobanu

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In compaction works, the most often used codes and standards are those for road embankments and refer to a maximum filling height of 3.00m. When filling a height greater than 3.00m, such codes are no longer valid and thus their application may lead to technical difficulties in the process of compaction and to the achievement of a sufficient degree of compaction. For this reason, in the case of controlled fillings with heights greater than 3.00m it is necessary to formulate and apply a number of special techniques, which can be determined by performing a full scale test. This paper presents the results of the studies and full scale tests conducted for the stabilization of a ravine with vertical banks and a depth of about 12.00m. The fillings will support a heavy traffic road connecting the two parts of a village in Vaslui County, Romania. After analyzing two comparative intervention solutions, the variant of a controlled filling bordered by a monolith concrete retaining wall was chosen. The results obtained by the authors highlighted the need to insert a geogrid reinforcement at every 2.00m for creating a 12.00m thick compacted fill.

Keywords: compaction, dynamic probing, stability, soil stratification

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Authors: Tomas O. Ortega, Cecilia T. Reyes, Cecile O. Legaspi, Cylde G. Abayon, Anna Mae C. Relingo, Mary Eden M. Teruel

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A study was conducted to evaluate the performance in the delivery of environmental management programs of the local government of Malay, Aklan, Philippines. The samples were determined by adopting the Multi-Stage Random Probability Sampling technique. The 150 respondents were drawn from barangays with larger shares of the population based on the Philippine Statistical Authority’s Data on Census Population and Housing for the year 2015. The qualified sample respondents were selected using the Kish Grid. Female respondents were targeted for even numbered questionnaires while male respondents were targeted for odd numbers. The four major core concepts namely awareness, availment, satisfaction and need for action were used in measuring the rating of the respondents and presented in frequency and percentage distributions. The reasons for their response were likewise gathered. The study inferred that a large portion of the respondents was profoundly aware of the environmental management programs implemented by their local government unit especially the solid waste management and the clean-up programs/projects. Programs to control air pollution and waste water management obtained the least awareness ratings from the respondents. A high percentage of respondents had availed of environmental management programs, particularly solid waste management. Overall, majority of the respondents were satisfied with the environmental management programs rendered by the local government unit and therefore needs less action. It is recommended that the local government unit must strengthen air pollution control program. Appropriate action must be taken to support the people’s interest in this program most particularly to the individuals who burn their garbage. Seminars and training-workshops about appropriate waste disposal will most likely help settle this issue.

Keywords: availment, awareness, environmental management, need for action, satisfaction

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Authors: Priya Arora, Jaspreet K. Rajput

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Superparamagnetism has accelerated the research and use of more economical and ecological magnetically separable catalysts due to their more efficient isolation by response to an applied magnetic field. Magnetite nanomaterials coated by SiO2 shell have received a great deal of focus in the last decades as it provides high stability and also easy further surface functionalization depending upon the application. In this protocol, Fe3O4 magnetic nanoparticles have been synthesized by co-precipitation combined with sonication method. Further, Fe3O4 superparamagnetic nanoparticles have been functionalized by various moieties to serve as efficient catalysts for multicomponent reactions. The functionalized nanoparticles were characterized by techniques like Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) surface area analysis. The as prepared nanocatalysts can be reused for several times without any significant loss in its activity. The utilization of magnetic nanoparticles as catalysts for this reaction is one approach i.e. green, inexpensive, facile and widely applicable.

Keywords: functionalized, magnetite, multicomponent reactions, superparamagnetic

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Authors: Marianna I. Triantou, Konstantina I. Stathi, Petroula A. Tarantili

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In the present study, the incorporation of graphene into blends of acrylonitrile-butadiene-styrene terpolymer with polypropylene (ABS/PP) was investigated focusing on the improvement of their thermomechanical characteristics and the effect on their rheological behavior. The blends were prepared by melt mixing in a twin-screw extruder and were characterized by measuring the MFI as well as by performing DSC, TGA and mechanical tests. The addition of graphene to ABS/PP blends tends to increase their melt viscosity, due to the confinement of polymer chains motion. Also, graphene causes an increment of the crystallization temperature (Tc), especially in blends with higher PP content, because of the reduction of surface energy of PP nucleation, which is a consequence of the attachment of PP chains to the surface of graphene through the intermolecular CH-π interaction. Moreover, the above nanofiller improves the thermal stability of PP and increases the residue of thermal degradation at all the investigated compositions of blends, due to the thermal isolation effect and the mass transport barrier effect. Regarding the mechanical properties, the addition of graphene improves the elastic modulus, because of its intrinsic mechanical characteristics and its rigidity, and this effect is particularly strong in the case of pure PP.

Keywords: acrylonitrile-butadiene-styrene terpolymer, blends, graphene, polypropylene

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Authors: Abu Salim Mustafa

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Rv3873 is a relatively large size protein (371 amino acids in length) and its gene is located in the immunodominant genomic region of difference (RD)1 that is present in the genome of Mycobacterium tuberculosis but deleted from the genomes of all the vaccine strains of Bacillus Calmette Guerin (BCG) and most other mycobacteria. However, when tested for cellular immune responses using peripheral blood mononuclear cells from tuberculosis patients and BCG-vaccinated healthy subjects, this protein was found to be a major stimulator of cell mediated immune responses in both groups of subjects. In order to further identify the sequence of immunodominant epitopes and explore their Human Leukocyte Antigen (HLA)-restriction for epitope recognition, 24 peptides (25-mers overlapping with the neighboring peptides by 10 residues) covering the sequence of Rv3873 were synthesized chemically using fluorenylmethyloxycarbonyl chemistry and tested in cell mediated immune responses. The results of these experiments helped in the identification of an immunodominant peptide P9 that was recognized by people expressing varying HLA-DR types. Furthermore, it was also predicted to be a promiscuous binder with multiple epitopes for binding to HLA-DR, HLA-DP and HLA-DQ alleles of HLA-class II molecules that present antigens to T helper cells, and to HLA-class I molecules that present antigens to T cytotoxic cells. In addition, the evaluation of peptide P9 using an immunogenicity predictor server yielded a high score (0.94), which indicated a greater probability of this peptide to elicit a protective cellular immune response. In conclusion, P9, a peptide with multiple epitopes and ability to bind several HLA class I and class II molecules for presentation to cells of the cellular immune response, may be useful as a peptide-based vaccine against tuberculosis.

Keywords: mycobacterium tuberculosis, PPE68, peptides, vaccine

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Authors: Nick Papanikolaou

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In modern world politics, International relations are very complex not only in their construction but also in their interpretation the ex-Yugoslavian(western Balkans) countries, due to the establishment of independent states, have also risen pending geopolitical and territorial issues such as the Kosovo dispute widely known as an active frozen conflict. Science of anthropology and its subfield of anthropology of conflict can suggest a sustainable plan of communities coexistence and abolishment of fondamentalism. The 1244 Security Council Resolution provides a framework of implementation of a transitional international joint international armed presence for ensuring control and stability in the territory. The changing international relations landscape and the rise of the integration of the Western Balkans in the European Union have brought the question of Kosovo and all the till now internationally controlled system of governance to a dead end. A new solution that will ensure a sustainable future needs to be applied in order to solve this case in a way that rights of both albanians and Serbians will be equally respected and both populations will coexist peacefully. What this presentation aims for is to present a plan for the peaceful coexistence and sovreignty of habitants of Kosovo in a whole new way of governance.

Keywords: sovereignty, Kosovo, Western Balkans, anthropology of conflict

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Authors: Faheema Khan

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We have investigated the effects of salt stress on the stability of plant growth, water relations, photosynthetic variables, lipid peroxidation and antioxidant system in salt-tolerant (PK-327) and salt-sensitive (PK-471) soybean genotypes. Ten-day-old salt-tolerant and salt-sensitive soybean plants were subjected to 0-150 mM NaCl for 15 days. While the growth of genotype PK-327 was not affected significantly up to 75 mM NaCl treatment, the growth of the PK-471 was reduced significantly beyond 25 mM NaCl treatments. Salt stress caused severe impairments in photosynthetic variables like photosynthetic rate, chlorophyll fluorescence and chlorophyll content, being more pronounced in salt-sensitive genotype than in salt-tolerant.The activities of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) were higher in PK-327 than in PK-471 at various levels of salt treatments.It is concluded that tolerance capacity of PK-327 against salinity can be associated with the ability of this genotype in keeping an active photosynthetic system and strong antioxidant defence system.

Keywords: salt stress, soybean, antioxidant, photosynthesis

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Authors: Shaoying Guo, Yanyun Xu, Meng Zhang, Weiqing Huang

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The wireless communication network is developing rapidly, thus the wireless security becomes more and more important. Specific emitter identification (SEI) is an vital part of wireless communication security as a technique to identify the unique transmitters. In this paper, a SEI method based on multiscale dispersion entropy (MDE) and refined composite multiscale dispersion entropy (RCMDE) is proposed. The algorithms of MDE and RCMDE are used to extract features for identification of five wireless devices and cross-validation support vector machine (CV-SVM) is used as the classifier. The experimental results show that the total identification accuracy is 99.3%, even at low signal-to-noise ratio(SNR) of 5dB, which proves that MDE and RCMDE can describe the communication signal series well. In addition, compared with other methods, the proposed method is effective and provides better accuracy and stability for SEI.

Keywords: cross-validation support vector machine, refined com- posite multiscale dispersion entropy, specific emitter identification, transient signal, wireless communication device

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Authors: Petra Buzkova, Milos Kopa

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Reliability of the credit default swap market had been questioned repeatedly during the EMU debt crisis. The article examines whether this development influenced sovereign EMU CDS prices in general. We regress the CDS market price on a model risk neutral CDS price obtained from an adopted reduced form valuation model in the 2009-2013 period. We look for a break point in the single-equation and multi-equation econometric models in order to show the changes in relations between CDS market and model prices. Our results differ according to the risk profile of a country. We find that in the case of riskier countries, the relationship between the market and model price changed when market participants started to question the ability of CDS contracts to protect their buyers. Specifically, it weakened after the change. In the case of less risky countries, the change happened earlier and the effect of a weakened relationship is not observed.

Keywords: chow stability test, credit default swap, debt crisis, reduced form valuation model, seemingly unrelated regression

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Authors: Csilla Dudás, Éva Böszörményi, Bence Kutus, István Pálinkó, Pál Sipos

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In this study the behavior of alpha-D-isosaccharinate (2-hydroxymethyl-3-deoxy-D-erythro-pentonate, ISA−) in alkaline medium in the presence of calcium was studied. At first the Ca–ISA system was studied by Ca-ion selective electrode (Ca-ISE) in neutral medium at T = 25 °C and I = 1 M NaCl to determine the formation constant of the CaISA+ monocomplex, which was found to be logK = 1.01 ± 0.01 for the reaction of Ca2+ + ISA– = CaISA+. In alkaline medium pH potentiometric titrations were carried out to determine the composition and stability constant of the complex(es) formed. It was found that in these systems above pH = 12.5 the predominant species is the CaISAOH complex. Its formation constant was found to be logK = 3.04 ± 0.05 for the reaction of Ca2+ + ISA– + H2O = CaISAOH + H+ at T = 25 °C and I = 1 M NaCl. Solubility measurements resulted in data consistent with those of the potentiometric titrations. Temperature dependent NMR spectra showed that the slow exchange range between the complex and the free ligand is below 5 °C. It was also showed that ISA– acts as a multidentate ligand forming macrochelate Ca-complexes. The structure of the complexes was determined by using ab initio quantum chemical calculations.

Keywords: Ca-ISE potentiometry, calcium complexes, isosaccharinate ion, NMR spectroscopy, pH potentiometry

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Authors: A. Farhad Sadri, B. Ali Farhadi, C. Nasim Shalamzari

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Waste management is a principle of urban and environmental governance. Waste management in Tehran metropolitan requires good strategies for better governance. Using of good urban governance principles together with eight main indexes can be an appropriate base for this aim. One of the reasonable tools in this field is usage of SWOT methods which provides possibility of comparing the opportunities, threats, weaknesses, and strengths by using IFE and EFE matrixes. The results of the above matrixes, respectively 2.533 and 2.403, show that management system of Tehran metropolitan wastes has performed weak regarding to internal factors and has not have good performance regarding using the opportunities and dealing with threats. In this research, prioritizing and describing the real value of each 24 strategies in waste management in Tehran metropolitan have been surveyed considering good governance derived from Quantitative Strategic Planning Management (QSPM) by using Kolomogrof-Smirnoff by 1.549 and significance level of 0.073 in order to define normalization of final values and all of the strategies utilities and Variance Analysis of ANOVA has been calculated for all SWOT strategies. Duncan’s test results regarding four WT, ST, WO, and SO strategies show no significant difference. In addition to mean comparison by Duncan method in this research, LSD (Lowest Significant Difference test) has been used by probability of 5% and finally, 7 strategies and final model of Tehran metropolitan waste management strategy have been defined. Increasing the confidence of people with transparency of budget, developing and improving the legal structure (rule-oriented and law governance, more responsibility about requirements of private sectors, increasing recycling rates and real effective participation of people and NGOs to improve waste management (contribution) and etc, are main available strategies which have been achieved based on good urban governance management principles.

Keywords: waste, strategy, environmental management, urban good governance, SWOT

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Authors: Konrad Pietrykowski, Michal Bialy, Pawel Karpinski, Radoslaw Maczka

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The nozzle is an element of the rocket engine in which the conversion of the potential energy of gases generated during combustion into the kinetic energy of the gas stream takes place. The design parameters of the nozzle have a decisive influence on the ballistic characteristics of the engine. Designing a nozzle assembly is, therefore, one of the most responsible stages in developing a rocket engine design. The paper presents the results of the simulation of three types of rocket propulsion nozzles. Calculations were made using CFD (Computational Fluid Dynamics) in ANSYS Fluent software. The next types of nozzles differ in shape. The analysis was made of a conical nozzle, a bell type nozzle with a conical supersonic part and a bell type nozzle. Calculation results are presented in the form of pressure, velocity and kinetic energy distributions of turbulence in the longitudinal section. The courses of these values along the nozzles are also presented. The results show that the cone nozzle generates strong turbulence in the critical section. Which negatively affect the flow of the working medium. In the case of a bell nozzle, the transformation of the wall caused the elimination of flow disturbances in the critical section. This reduces the probability of waves forming before or after the trailing edge. The most sophisticated construction is the bell type nozzle. It allows you to maximize performance without adding extra weight. The bell type nozzle can be used as a starter and auxiliary engine nozzle due to its advantages. The project/research was financed in the framework of the project Lublin University of Technology-Regional Excellence Initiative, funded by the Polish Ministry of Science and Higher Education (contract no. 030/RID/2018/19).

Keywords: computational fluid dynamics, nozzle, rocket engine, supersonic flow

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Authors: Chui Ling Teng, R. Matsa

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We report a case with combined overdose of Lercanidipine (non-dihydropyridine calcium channel blocker), Quetiapine (Atypical antipsychotic), Ramipril and Duloxetine. A 66-year old male presented to the Emergency Department 12-hours after the ingestion of 1.2g Lercanidipine, 3g Quetiapine, 280mg of Ramipril and 420mg of Duloxetine. He describes lethargic, drowsiness and was unable to pass any urine since overdosed. He was found to be bradycardic, hypotensive and anuric. He had refractory hypotension and anuric despite fluid resuscitation, glucagon therapy and intravenous naloxone. His care was escalated to Intensive care, requiring noradrenaline, adrenaline, vasopressin, and hyperinsulinaemic euglycaemia therapy. He achieved haemodynamic stability and kidney function improved gradually with the support received. The total length of therapy lasted for 30 horus in which individual therapy was weaned down based on the requirement. He was then transferred to medical ward for further psychiatric assessment. This is a the first repored case of mixed overdose with lercanidipine, Quetiapine, Rampmipril and Duloxetine.

Keywords: calcium channel blocker, hyperinsulinaemic Euglycaemia therapy, lercanidipine, overdose

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Authors: D. Calogine, O. Chau, S. Dotti, O. Ramiarinjanahary, P. Rasoavonjy, F. Tovondahiniriko

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Mafate is a natural circus in the north-western part of Reunion Island, without an electrical grid and road network. A micro-grid concept is being experimented in this area, composed of a photovoltaic production combined with electrochemical batteries, in order to meet the local population for self-consumption of electricity demands. This work develops a discrete model as well as a stochastic model in order to reach an optimal equilibrium between production and consumptions for a cluster of houses. The management of the energy power leads to a large linearized programming system, where the time interval of interest is 24 hours The experimental data are solar production, storage energy, and the parameters of the different electrical devices and batteries. The unknown variables to evaluate are the consumptions of the various electrical services, the energy drawn from and stored in the batteries, and the inhabitants’ planning wishes. The objective is to fit the solar production to the electrical consumption of the inhabitants, with an optimal use of the energies in the batteries by satisfying as widely as possible the users' planning requirements. In the discrete model, the different parameters and solutions of the linear programming system are deterministic scalars. Whereas in the stochastic approach, the data parameters and the linear programming solutions become random variables, then the distributions of which could be imposed or established by estimation from samples of real observations or from samples of optimal discrete equilibrium solutions.

Keywords: photovoltaic production, power consumption, battery storage resources, random variables, stochastic modeling, estimations of probability distributions, mixed integer linear programming, smart micro-grid, self-consumption of electricity.

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Authors: Jurriaan Gillissen

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This work is concerned with stabilizing the numerical integration of the Navier-Stokes equation (NSE), backwards in time. Applications involve the detection of sources of, e.g., sound, heat, and pollutants. Stable reverse numerical integration of parabolic differential equations is also relevant for image de-blurring. While the literature addresses the reverse integration problem of the advection-diffusion equation, the problem of numerical reverse integration of the NSE has, to our knowledge, not yet been addressed. Owing to the presence of viscosity, the NSE is irreversible, i.e., when going backwards in time, the fluid behaves, as if it had a negative viscosity. As an effect, perturbations from the perfect solution, due to round off errors or discretization errors, grow exponentially in time, and reverse integration of the NSE is inherently unstable, regardless of using an implicit time integration scheme. Consequently, some sort of filtering is required, in order to achieve a stable, numerical, reversed integration. The challenge is to find a filter with a minimal adverse affect on the accuracy of the reversed integration. In the present work, we explore an adjoint gradient method (AGM) to achieve this goal, and we apply this technique to two-dimensional (2D), decaying turbulence. The AGM solves for the initial velocity field u0 at t = 0, that, when integrated forward in time, produces a final velocity field u1 at t = 1, that is as close as is feasibly possible to some specified target field v1. The initial field u0 defines a minimum of a cost-functional J, that measures the distance between u1 and v1. In the minimization procedure, the u0 is updated iteratively along the gradient of J w.r.t. u0, where the gradient is obtained by transporting J backwards in time from t = 1 to t = 0, using the adjoint NSE. The AGM thus effectively replaces the backward integration by multiple forward and backward adjoint integrations. Since the viscosity is negative in the adjoint NSE, each step of the AGM is numerically stable. Nevertheless, when applied to turbulence, the AGM develops instabilities, which limit the backward integration to small times. This is due to the exponential divergence of phase space trajectories in turbulent flow, which produces a multitude of local minima in J, when the integration time is large. As an effect, the AGM may select unphysical, noisy initial conditions. In order to improve this situation, we propose two remedies. First, we replace the integration by a sequence of smaller integrations, i.e., we divide the integration time into segments, where in each segment the target field v1 is taken as the initial field u0 from the previous segment. Second, we add an additional term (regularizer) to J, which is proportional to a high-order Laplacian of u0, and which dampens the gradients of u0. We show that suitable values for the segment size and for the regularizer, allow a stable reverse integration of 2D decaying turbulence, with accurate results for more then O(10) turbulent, integral time scales.

Keywords: time reversed integration, parabolic differential equations, adjoint gradient method, two dimensional turbulence

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Authors: Farzana Majid, Mahwish Bashir, Ammara, Attia Falak

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Zirconia nanoparticles have gained significant attention due to their excellent mechanical strength, thermal properties, biocompatibility, and catalytic activity. Tetragonal zirconia holds the greatest efficacy for surgical implants and coatings when it comes to the three zirconia phases (monoclinic, tetragonal, and cubic). However, its stability at higher temperatures and transformation to the monoclinic phase upon cooling are challenging. In this research, zirconia nanoparticles were prepared using microwave-assisted sol-gel method with varying microwave powers (100 W, 300 W, 500 W, 700 W, & 900 W). Organic stabilizing agent, i.e., eggshell powder, was used to stabilize the tetragonal phase. Fourier transform infrared spectroscopy (FTIR) confirmed the phase-pure tetragonal zirconia, corroborating the XRD data. Optical properties, including the optical bandgap, were studied using UV/Visible and PL spectroscopies. The synthesized ZrO2 nanoparticles exhibited excellent photocatalytic degradation efficiency in the degradation of methylene blue (MB) dye under UV irradiation. The findings demonstrate the potential of these ZrO2 nanoparticles as a viable alternative photocatalyst for the efficient degradation of various dyes in contaminated water.

Keywords: zirconia nanoparticles, sol-gel, photocataylsis, wter purification

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Authors: Nathi Ram, Saurabh K. Yadav

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In turbomachinery, the turbulent flow occurs due to the use of high velocity of low kinematic viscosity lubricants and used in many industrial applications. In the present work, the performance of symmetric slot-entry hybrid worn journal bearing under laminar and turbulent lubrication has been investigated. For turbulent lubrication, the Reynolds equation has been modified using Constantinescu turbulent model. This modified equation has been solved using the finite element method. The effect of turbulent lubrication on bearing’s performance has been presented for symmetric hybrid journal bearing. The slot-entry hybrid worn journal bearing under turbulent/laminar regimes have been investigated. It has been observed that the stiffness and damping coefficients are more for the bearing having slot width ratio (SWR) of 0.25 than the bearing with SWR of 0.5 and 0.75 under the turbulent regime. Further, it is also observed that for constant wear depth parameter, stability threshold speed gets increased for bearing operates at slot width ratio 0.25 under turbulent lubrication.

Keywords: hydrostatic bearings, journal bearings, restrictors, turbulent flow models, finite element technique

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Authors: Zakaria Ahmed, Khaled Charradi, Sherif M. A. S. Keshk, Radhouane Chtourou

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Sulfonated poly ether ether ketone (SPEEK) with a low sulfonation degree was blended using nanofiller Layered Double Hydroxide (LDH, Mg2AlCl) /sepiolite nanostructured material as additive to use as an electrolyte membrane for fuel cell application. Characterization assessments, i.e., mechanical stability, thermal gravimetric analysis, ion exchange capability, swelling properties, water uptake capacities, electrochemical impedance spectroscopy analysis, and Fourier transform infrared spectroscopy (FTIR) of the composite membranes were conducted. The presence of LDH/sepiolite nanoarchitecture material within SPEEK was found to have the highest water retention and proton conductivity value at high temperature rather than LDH/SPEEK and pristine SPEEK membranes.

Keywords: SPEEK, sepiolite clay, LDH clay, proton exchange membrane

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Authors: J. S. S. Neto, R. A. A. Lima, D. K. K. Cavalcanti, J. P. B. Souza, R. A. A. Aguiar, M. D. Banea

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In the last decade, investments in sustainable processes and products have gained space in several segments, such as in the civil, automobile, textile and other industries. In addition to increasing concern about the development of environmentally friendly materials that reduce, energy costs and reduces environmental impact in the production of these products, as well as reducing CO2 emissions. Natural fibers offer a great alternative to replace synthetic fibers, totally or partially, because of their low cost and their renewable source. The purpose of this research is to study the effect of surface chemical treatment on the thermal properties of hybrid fiber reinforced natural fibers (NFRC), jute + ramie, jute + sisal, jute + curauá, and jute fiber in polymer matrices. Two types of chemical treatment: alkalinization and silanization were employed, besides the condition without treatment. Differential scanning calorimetry (DSC), thermogravimetry (TG) and dynamic-mechanical analysis (DMA) were performed to explore the thermal stability and weight loss in the natural fiber reinforced composite as a function of chemical treatment.

Keywords: chemical treatment, hybrid composite, jute, thermal

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Authors: K. Swapna

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A Series of Alkali-Earth Boro Tellurite (AEBT) glasses doped with different concentrations of Dy³⁺ ions have been prepared by using melt quenching technique and characterized through spectroscopic techniques such as optical absorption, excitation, emission and photoluminescence decay to understand their utility in optoelectronic devices such as lasers and white light emitting diodes (w-LEDs). Raman spectrum recorded for an undoped glass is used to measure the phonon energy of the host glass and various functional groups present in the host glass (AEBT). The intensities of the electronic transitions and the ligand environment around the Dy³⁺ ions were studied by applying Judd-Ofelt (J-O) theory to the recorded absorption spectra of the glasses. The evaluated J-O parameters are subsequently used to measure various radiative parameters such as transition probability (AR), radiative branching ratio (βR) and radiative lifetimes (τR) for the prominent fluorescent levels of Dy³⁺ ions in the as-prepared glasses. The luminescence spectra recorded at 387 nm excitation show three emission transitions (⁴F9/2→⁶H15/2 (blue), ⁴F9/2→⁶H13/2 (yellow) and ⁴F9/2 → ⁶H11/2 (red)) of which the yellow transition observed at 575 nm is found to be highly intense. The experimental branching ratio (βexp) and stimulated emission crosssection (σse) were measured from luminescence spectra. The experimental lifetimes (τexp) measured from the decay spectral profiles are combined with radiative lifetimes to measure quantum efficiencies of the as-prepared glasses. The yellow to blue intensity ratios and chromaticity color coordinates are found to vary with Dy³⁺ ion concentrations. The aforementioned results reveal that these glasses are aptly suitable for w-LEDs and laser devices.

Keywords: glasses, J-O parameters, photoluminescence, I-H model

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Authors: Ana Luísa Mouro

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When the financial crisis exploded in 2008 in the United States, unleashed by the collapse of Lehman Brothers, and contaminated the economies of the European periphery, Germany appeared as the anchor of the stability of all European institutions and countries in difficulty. The solutions provided by the German government have triggered a deep political debate about the key position Germany has conquered at the heart of Europe - a new “German question” has been created. Some say Germany has achieved by peaceful means what was not able to get through military conquest - the domination of Europe – and many fear Germany’s economic power. This debate about the new role of Germany in Europe has received special attention in the European media and Portugal has not been the exception. The present study has been based on the survey, selection and critical analysis of news reporting, opinion articles, interviews and editorials, published in the weekly Expresso and in the daily Público, between 2008 and 2015 (year of the 25th anniversary of Germany’s unification). The findings of this study will show the paradox of German power and its relevance for Europe’s future.

Keywords: Euro crises, German Europe, intercultural hermeneutics, Portuguese quality press

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Authors: Yihao Kuang, Bowen Ding

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With the increasing scale and complexity of knowledge graph, modern knowledge graph contains more and more types of entity, relationship, and attribute information. Therefore, in recent years, it has been a trend for knowledge graph inference to use reinforcement learning to deal with large-scale, incomplete, and noisy knowledge graph and improve the inference effect and interpretability. The Proximal Policy Optimization (PPO) algorithm utilizes a near-end strategy optimization approach. This allows for more extensive updates of policy parameters while constraining the update extent to maintain training stability. This characteristic enables PPOs to converge to improve strategies more rapidly, often demonstrating enhanced performance early in the training process. Furthermore, PPO has the advantage of offline learning, effectively utilizing historical experience data for training and enhancing sample utilization. This means that even with limited resources, PPOs can efficiently train for reinforcement learning tasks. Based on these characteristics, this paper aims to obtain better and more efficient inference effect by introducing PPO into knowledge inference technology.

Keywords: reinforcement learning, PPO, knowledge inference, supervised learning

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Authors: Rinat Arbel-Goren, Joel Stavans

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Cell-to-cell variations in transcript or protein abundance, called noise, may give rise to phenotypic variability between isogenic cells, enhancing the probability of survival under stress conditions. These variations may be introduced by post-transcriptional regulatory processes such as non-coding, small RNAs stoichiometric degradation of target transcripts in bacteria. We study the iron homeostasis network in Escherichia coli, in which the RyhB small RNA regulates the expression of various targets as a model system. Using fluorescence reporter genes to detect protein levels and single-molecule fluorescence in situ hybridization to monitor transcripts levels in individual cells, allows us to compare noise at both transcript and protein levels. The experimental results and computer simulations show that extrinsic noise buffers through a feed-forward loop configuration the increase in variability introduced at the transcript level by iron deprivation, illuminating the important role that extrinsic noise plays during stress. Surprisingly, extrinsic noise also decouples of fluctuations of two different targets, in spite of RyhB being a common upstream factor degrading both. Thus, phenotypic variability increases under stress conditions by the decoupling of target fluctuations in the same cell rather than by increasing the noise of each. We also present preliminary results on the adaptation of cells to prolonged iron deprivation in order to shed light on the evolutionary role of post-transcriptional downregulation by small RNAs.

Keywords: cell-to-cell variability, Escherichia coli, noise, single-molecule fluorescence in situ hybridization (smFISH), transcript

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Authors: Mahshid Asadollahi, Mohammad Akbari Asl

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The restaurant industry is highly competitive, and restaurants are constantly looking for ways to attract new customers and retain their existing ones. Nonverbal communication is an important factor in creating a positive customer experience and can play a significant role in attracting customers to restaurants. Nonverbal communication can include body language, facial expressions, tone of voice, and physical proximity, among other things. The present study aimed to investigate the impact of nonverbal communication between restaurant employees and customers on attracting customers in food courts in Tehran. The research method was descriptive-correlational, and the statistical population of this study included all customers of food court restaurants in Tehran, which was about 30 restaurants. The research sample was selected through probability sampling, and 440 customers completed emotional response, customer satisfaction, and nonverbal communication questionnaires in person. The data obtained were analyzed using multiple regression analysis. The results showed that vocal language, employee proximity, physical appearance, and speech movements, as components of nonverbal communication of restaurant employees, had an impact on attracting customers. Additionally, positive and negative emotions of customers have a significant relationship with customer attraction in Food Court restaurants. The study shows that various nonverbal communication factors can play a significant role in attracting customers, and that positive and negative customer emotions can affect customer satisfaction. Therefore, restaurant owners and managers should pay attention to nonverbal communication and train their employees accordingly to create a positive and welcoming atmosphere for customers.

Keywords: verbal language, proximity of employees, physical appearance, speech gestures, nonverbal communication, customer emotions, customer attraction

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Authors: Marwa Zein

Abstract:

The long-term of the contract is one of the major features that distinguish international trade and investment contracts from other internal contracts. This is due to the nature of the contract and the huge works required to be performed from one hand or the desire of the parties to achieve stability in their transactions. However, long-term contracts might expose them to certain events and circumstances that impact the capability of the parties to execute their obligations pursuant to these contracts. During the year 2016, the Egyptian government has taken series of economic decisions which greatly impacted the economic and investment environment. Consequently, many contracts have encountered many problems in their execution due to such changes that greatly influence the performance of their obligation, a matter that necessitated the renegotiation of the conditions of these contracts on the basis of the unpredicted changes that could be listed under the Force Majeure Clause. The principle of fair and equitable treatment in investment placed on an obligation on the Egyptian government to consider the renegotiation of contract clauses based on the new conditions. This paper will discuss the idea of renegotiating international trade and investment contracts in Egypt with reference to the changes the economic environment has witnessed lately.

Keywords: change of circumstances, international contracts, investment contracts, renegotiation

Procedia PDF Downloads 181

Authors: N. Hatraf, L. Merabti, Z. Neffah, W. Taane

Abstract:

The excessive consumption of fossil energies (electrical energy) during summer caused by the technological development involves more and more climate warming. In order to reduce the worst impact of gas emissions produced from classical air conditioning, heat driven solar absorption chiller is pretty promising; it consists on using solar as motive energy which is clean and environmentally friendly to provide cold. Solar absorption machine is composed by four components using Lithium Bromide /water as a refrigerating couple. LiBr- water is the most promising in chiller applications due to high safety, high volatility ratio, high affinity, high stability and its high latent heat. The lithium bromide solution is constitute by the salt lithium bromide which absorbs water under certain conditions of pressure and temperature however if the concentration of the solution is high in the absorption chillers; which exceed 70%, the solution will crystallize. The main aim of this article is to study the phenomena of the crystallization and to evaluate how the dependence between the electric conductivity and the concentration which should be controlled.

Keywords: absorption, crystallization, experimental results, lithium bromide solution

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Authors: Ling Ai Wong, Hussain Shareef, Azah Mohamed, Ahmad Asrul Ibrahim

Abstract:

The installation of photovoltaic based distributed generation (PVDG) in active distribution system can lead to voltage fluctuation due to the intermittent and unpredictable PVDG output power. This paper presented a method in mitigating the voltage rise by optimally locating and sizing the battery energy storage system (BESS) in PVDG integrated distribution network. The improved firefly algorithm is used to perform optimal placement and sizing. Three objective functions are presented considering the voltage deviation and BESS off-time with state of charge as the constraint. The performance of the proposed method is compared with another optimization method such as the original firefly algorithm and gravitational search algorithm. Simulation results show that the proposed optimum BESS location and size improve the voltage stability.

Keywords: BESS, firefly algorithm, PVDG, voltage fluctuation

Procedia PDF Downloads 309

Authors: Ather Saeed, Arif Khan, Jeffrey Gosper

Abstract:

Sensor devices are prone to errors and sudden node failures, which are difficult to detect in a timely manner when deployed in real-time, hazardous, large-scale harsh environments and in medical emergencies. Therefore, the loss of data can be life-threatening when the sensed phenomenon is not disseminated due to sudden node failure, battery depletion or temporary malfunctioning. We introduce a set of partial differential equations for localizing faults, similar to Green’s and Maxwell’s equations used in Electrostatics and Electromagnetism. We introduce a node organization and clustering scheme for self-stabilizing sensor networks. Green’s theorem is applied to regions where the curve is closed and continuously differentiable to ensure network connectivity. Experimental results show that the proposed GTFD (Green’s Theorem fault-detection and Self-stabilization) protocol not only detects faulty nodes but also accurately generates network stability graphs where urgent intervention is required for dynamically self-stabilizing the network.

Keywords: Green’s Theorem, self-stabilization, fault-localization, RSSI, WSN, clustering

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Authors: Niroshan K. Walgama Wellalage, Tieling Zhang, Richard Dwight

Abstract:

State-based Markov deterioration models (SMDM) sometimes fail to find accurate transition probability matrix (TPM) values, and hence lead to invalid future condition prediction or incorrect average deterioration rates mainly due to drawbacks of existing nonlinear optimization-based algorithms and/or subjective function types used for regression analysis. Furthermore, a set of separate functions for each condition state with age cannot be directly derived by using Markov model for a given bridge element group, which however is of interest to industrial partners. This paper presents a new approach for generating Homogeneous SMDM model output, namely, the Modified Weibull approach, which consists of a set of appropriate functions to describe the percentage condition prediction of bridge elements in each state. These functions are combined with Bayesian approach and Metropolis Hasting Algorithm (MHA) based Markov Chain Monte Carlo (MCMC) simulation technique for quantifying the uncertainty in model parameter estimates. In this study, factors contributing to rail bridge deterioration were identified. The inspection data for 1,000 Australian railway bridges over 15 years were reviewed and filtered accordingly based on the real operational experience. Network level deterioration model for a typical bridge element group was developed using the proposed Modified Weibull approach. The condition state predictions obtained from this method were validated using statistical hypothesis tests with a test data set. Results show that the proposed model is able to not only predict the conditions in network-level accurately but also capture the model uncertainties with given confidence interval.

Keywords: bridge deterioration modelling, modified weibull approach, MCMC, metropolis-hasting algorithm, bayesian approach, Markov deterioration models

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Authors: Han Xiao, Ruan Qi, Zhang Lei, Qi Yan

Abstract:

Space environment simulator is a facility used to conduct thermal test for spacecraft, and vacuum vessel is the main body of it. According to the requirements for thermal tests of the spacecraft and its solar array panels, the primary vessel and the side vessels are designed to be a combinative structure connected with aperture, which ratio reaches 0.7. Since the vacuum vessel suffers 0.1MPa external pressure during the process of thermal test, in order to ensure the simulator’s reliability and safety, it’s necessary to calculate the vacuum vessel’s intensity and stability. Based on the impact of large openings to vacuum vessel structure, this paper explored the reinforce design and analytical way of vacuum vessel with large openings, using a large space environment simulator’s vacuum vessel design as an example. Tests showed that the reinforce structure is effective to fulfill the requirements of external pressure and the gravity. This ensured the reliability of the space environment simulator, providing a guarantee for developing the spacecraft.

Keywords: vacuum vessel, large opening, space environment simulator, structure design

Procedia PDF Downloads 512