Search results for: Constant Correlation

Authors: Hicham Salhi

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This research project focuses on the numerical investigation of the mixed convection of Hybrid nanofluids in a round bottom flask commonly used in organic chemistry synthesis. The aim of this study is to improve the thermal properties of the reaction medium and enhance the rate of chemical reactions by using hybrid nanofluids. The flat bottom wall of the flask is maintained at a constant high temperature, while the top, left, and right walls are kept at a low temperature. The nanofluids used in this study contain suspended Cu and Al2O3 nanoparticles in pure water. The governing equations are solved numerically using the finite-volume approach and the Boussinesq approximation. The effects of the volume fraction of nanoparticles (φ) ranging from 0% to 5%, the Rayleigh number from 103 to 106, and the type of nanofluid (Cu and Al2O3) on the flow streamlines, isotherm distribution, and Nusselt number are examined in the simulation. The results indicate that the addition of Cu and Al2O3 nanoparticles increases the mean Nusselt number, which improves heat transfer and significantly alters the flow pattern. Moreover, the mean Nusselt number increases with increasing Rayleigh number and volume fraction, with Cu- Al2O3 hybrid nanofluid producing the best results. This research project focuses on the numerical investigation of the mixed convection of Hybrid nanofluids in a round bottom flask commonly used in organic chemistry synthesis. The aim of this study is to improve the thermal properties of the reaction medium and enhance the rate of chemical reactions by using hybrid nanofluids. The flat bottom wall of the flask is maintained at a constant high temperature, while the top, left, and right walls are kept at a low temperature. The nanofluids used in this study contain suspended Cu and Al2O3 nanoparticles in pure water. The governing equations are solved numerically using the finite-volume approach and the Boussinesq approximation. The effects of the volume fraction of nanoparticles (φ) ranging from 0% to 5%, the Rayleigh number from 103 to 106, and the type of nanofluid (Cu and Al2O3) on the flow streamlines, isotherm distribution, and Nusselt number are examined in the simulation. The results indicate that the addition of Cu and Al2O3 nanoparticles increases the mean Nusselt number, which improves heat transfer and significantly alters the flow pattern. Moreover, the mean Nusselt number increases with increasing Rayleigh number and volume fraction, with Cu- Al2O3 hybrid nanofluid producing the best results.

Keywords: bottom flask, mixed convection, hybrid nanofluids, numerical simulation

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Authors: Anis A. Ansari, Aftab A. Ansari

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Electronic waste is inundating the traditional solid-waste-disposal facilities, which are inadequately designed to handle and manage such type of new wastes. Since electronic waste contains mostly hazardous and even toxic materials, the seriousness of its effects on human health and the environment cannot be ignored in present scenario. Waste from the electronic industry is increasing exponentially day by day. From the last 20 years, we are continuously generating huge quantities of e-waste such as obsolete computers and other discarded electronic components, mainly due to evolution of newer technologies as a result of constant efforts in research and development in this sector. Polymers, one of the major constituents in almost every electronic waste, such as computers, printers, electronic equipment, entertainment devices, mobile phones, television sets etc., are if properly recycled can create a new business opportunity. This would not only create potential market for polymers to improve economy but also the priceless land used as dumping sites of electronic waste, can be utilized for other productive purposes.

Keywords: polymer recycling, electronic waste, hazardous materials, electronic components

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Authors: Varvara Tyurina

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In the age of globalization Internet communication as a new format of interactions have become an integral part of our daily routine. Internet environment allows for new conditions and provides participants to a communication act with extra communication tools which can be used on Internet forums or in chat rooms. As a result communicants tend to alternate their behavior patterns in contrast to those practiced in live communication. It is not yet clear which communication strategies participants to Internet communication abide by and what determines their choices. Given the continually changing environment of a forum or a chat the behavior of a communicant can be interpreted in terms of autopoiesis theory which sees adaptation as the major tool for coexistence between the living system and its niche. Each communication act is seen as interaction between the communicant (i.e. the living system) and the overall environment of the forum (i.e. the niche) rather than one particular interlocutor. When communicating via the Internet participants are believed to aim at reaching a balance between themselves and the environment of a forum or a chat. The research focuses on unveiling the adaptation strategies employed by a communicant in particular cases and looks into the reasons they are employed. There is a correlation between language faculty of the communicants and the strategies they opt for when communicating on Internet forums and in chat rooms. The research included an experiment with a sample of Russian-English asymmetric bilinguals aged 16-25. Respondents were given two texts of equivalent contents, but of different language complexity. They had to respond to the texts as if they were making a reciprocal comment at a forum. It has been revealed that when communicants realize that their language faculty is not sufficient to understand the initial text they tend to amend their communication strategy in order to maintain the balance with the niche (remain involved in the communication). Most common strategies for responding to a difficult-to-understand text were self-presentation, veiling poor language faculty and response evasion. The research has so far focused on a very narrow aspect of correlation between language faculty and communication behavior, namely the syntactic and lexicological complexity of initial texts. It is essential to conduct a series of experiments that dwell on other characteristics of the texts to determine the range of cases when language faculty determines the choice of adaptation strategy.

Keywords: adaptation, communication strategies, internet communication, verbal interaction, autopoiesis theory

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Authors: Bahar Ayberk

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The study was conducted to determine the relationship between physical fitness and academic performance among university students. A far-famed saying ‘Sound mind in a sound body’ referring to the potential quality of increased physical fitness in the intellectual development of individuals seems to be endorsed. There is a growing body of literature the impact of physical fitness on academic achievement, especially in elementary and middle-school aged children. Even though there are numerous positive effects related to being physically active and physical fitness, their effect on academic achievement is not very much clear for university students. The subjects for this study included 25 students (20 female and 5 male) enrolled in Yeditepe University, Physiotherapy and Rehabilitation Department of Health Science Faculty. All participants filled in a questionnaire about their socio-demographic status, general health status, and physical activity status. Health-related physical fitness testing, included several core components: 1) body composition evaluation (body mass index, waist-to-hip ratio), 2) cardiovascular endurance evaluation (queen’s college step test), 3) muscle strength and endurance evaluation (sit-up test, push-up test), 4) flexibility evaluation (sit and reach test). Academic performance evaluation was based on student’s Cumulative Grade Point Average (CGPA). The prevalence of the subjects participating physical activity was found to be 40% (n = 10). CGPA scores were significantly higher among students having regular physical activity when we compared the students having regular physical activities or not (respectively 2,71 ± 0.46, 3.02 ± 0.28 scores, p = 0.076). The result of the study also revealed that there is positive correlation relationship between sit-up, push up and academic performance points (CGPA) (r = 0.43, p ≤ 0.05 ) and negative correlation relationship between cardiovascular endurance parameter (Queen's College Step Test) and academic performance points (CGPA) (r = -0.47, p ≤ 0.05). In conclusion, the findings confirmed that physical fitness level was generally associated with academic performance in the study group. Cardiovascular endurance and muscle strength and endurance were associated with student’s CGPA, whereas body composition and flexibility were unrelated to CGPA.

Keywords: academic performance, health-related physical fitness, physical activity, physical fitness testing

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Authors: Yaping Zhao, Yimin Zhang

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In the present paper, the stationary random vibration of a uniform cantilever beam is investigated. Two types of damping mechanism, i.e. the external and internal viscous dampings, are taken into account simultaneously. The excitation form is the support motion, and it is ideal white. Because two type of damping mechanism are considered concurrently, the product of the modal damping ratio and the natural frequency is not a constant anymore. As a result, the infinite definite integral encountered in the process of computing the mean square response is more complex than that in the existing literature. One signal progress of this work is to have calculated these definite integrals accurately. The precise solution of the mean square response is thus obtained in the infinite series form finally. Numerical examples are supplied and the numerical outcomes acquired confirm the validity of the theoretical analyses.

Keywords: random vibration, cantilever beam, mean square response, white noise

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Authors: Amit Kumar Dwivedi, Priyanko Ghosh

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Data Envelopment analysis (DEA) has been used to calculate the technical and scale efficiency measures of the public and private sugar manufacturing firms of the Indian Sugar Industry (2006 to 2010). Within DEA framework, the input & Output oriented Variable Returns to Scale (VRS) & Constant Return to Scale (CRS) model is employed for the study of Decision making units (DMUs). A representative sample of 43 firms which account for major portion of the total market share is studied. The selection criterion for the inclusion of a firm in the analysis was the total sales of INR 5,000 million or more in the year 2010. After reviewing the literature it is found that no study has been conducted in the context of Indian sugar manufacturing firms in the Post-liberalization era which motivates us to initiate the study.

Keywords: technical efficiency, Indian sugar manufacturing units, DEA, input output oriented

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Authors: Eric Chabrol, Sidonia B.G. Eckle, Renate de Boer, James McCluskey, Jamie Rossjohn, Mirjam H.M. Heemskerk, Stephanie Gras

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αβ and γδ T-cells are disparate T-cell lineages that, via their use of either αβ or γδ T-cell antigen receptors (TCRs) respectively, can respond to distinct antigens. Here we characterise a new population of human T-cells, term δβ T-cells, that express TCRs comprising a TCR-δ variable gene fused to a Joining-α/Constant-α domain, paired with an array of TCR-β chains. We characterised the cellular, functional, biophysical and structural characteristic feature of this new T-cells population that reveal some new insight into TCR diversity. We provide molecular bases of how δβ T-cells can recognise viral peptide presented by Human Leukocyte Antigen (HLA) molecule. Our findings highlight how components from αβ and γδTCR gene loci can recombine to confer antigen specificity thus expanding our understanding of T-cell biology and TCR diversity.

Keywords: new delta-beta TCR, HLA, viral peptide, structural immunology

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Authors: Mahmoud Huleihil

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In this study, the performance of a thermodynamic gas cycle of magnetohydrodynamic (MHD) power generation is considered and presented in terms of power efficiency curves. The dissipation mechanisms considered include: fluid friction modeled by means of the isentropic efficiency of the compressor, heat transfer leakage directly from the hot reservoir to the cold heat reservoir, and constant velocity of the MHD generator. The study demonstrates that power and efficiency vanish at the extremes of both slow and fast operating conditions. These points are demonstrated on power efficiency curves and the locus of efficiency at maximum power and the locus of maximum efficiency. Qualitatively, the considered loss mechanisms have a similar effect on the efficiency at maximum power operation and on maximum efficiency operation, thus these efficiencies are reduced, even for small values of the loss mechanisms.

Keywords: magnetohydrodynamic generator, electrical efficiency, maximum power, maximum efficiency, heat engine

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Authors: M. J. Gazapo Lapayese

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It is a well-established fact that terrorism is one of the foremost threats to present-day international security. The creation of tools or mechanisms for confronting it in an effective and efficient manner will only be possible by way of an objective assessment of the phenomenon. In order to achieve this, this paper has the following three main objectives: Firstly, setting out to find the reasons that have prevented the establishment of a universally accepted definition of terrorism, and consequently trying to outline the main features defining the face of the terrorist threat in order to discover the fundamental goals of what is now a serious blight on world society. Secondly, trying to explain the differences between a terrorist movement and a terrorist organisation, and the reasons for which a terrorist movement can be led to transform itself into an organisation. After analysing these motivations and the characteristics of a terrorist organisation, an example of the latter will be succinctly analysed to help the reader understand the ideas expressed. Lastly, discovering and exposing the factors that can lead to the appearance of terrorist tendencies, and discussing the most efficient and effective responses that can be given to this global security threat.

Keywords: responses, resilience, security, terrorism

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Authors: Elvis Medina, Alejandro Karelovic, Romel Jiménez

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Catalytic ammonia decomposition represents an attractive alternative due to its high H₂ content (17.8% w/w), a product stream free of COₓ, among others; however, challenges need to be addressed for its consolidation as an H₂ chemical storage technology, especially, those focused on the synthesis of efficient bimetallic catalytic systems, as an alternative to the price and scarcity of ruthenium, the most active catalyst reported. In this sense, from the perspective of rational catalyst design, adjusting the main catalytic activity descriptor, a screening of supported catalysts with different compositional settings of cobalt-molybdenum metals is presented to evaluate their effect on the catalytic decomposition rate of ammonia. Subsequently, a kinetic study on the supported monometallic Co and Mo catalysts, as well as on the bimetallic CoMo catalyst with the highest activity is shown. The synthesis of catalysts supported on γ-alumina was carried out using the Charge Enhanced Dry Impregnation (CEDI) method, all with a 5% w/w loading metal. Seeking to maintain uniform dispersion, the catalysts were oxidized and activated (In-situ activation) using a flow of anhydrous air and hydrogen, respectively, under the same conditions: 40 ml min⁻¹ and 5 °C min⁻¹ from room temperature to 600 °C. Catalytic tests were carried out in a fixed-bed reactor, confirming the absence of transport limitations, as well as an Approach to equilibrium (< 1 x 10⁻⁴). The reaction rate on all catalysts was measured between 400 and 500 ºC at 53.09 kPa NH3. The synergy theoretically (DFT) reported for bimetallic catalysts was confirmed experimentally. Specifically, it was observed that the catalyst composed mainly of 75 mol% cobalt proved to be the most active in the experiments, followed by the monometallic cobalt and molybdenum catalysts, in this order of activity as referred to in the literature. A kinetic study was performed at 10.13 – 101.32 kPa NH3 and at four equidistant temperatures between 437 and 475 °C the data were adjusted to an LHHW-type model, which considered the desorption of nitrogen atoms from the active phase surface as the rate determining step (RDS). The regression analysis were carried out under an integral regime, using a minimization algorithm based on SLSQP. The physical meaning of the parameters adjusted in the kinetic model, such as the RDS rate constant (k₅) and the lumped adsorption constant of the quasi-equilibrated steps (α) was confirmed through their Arrhenius and Van't Hoff-type behavior (R² > 0.98), respectively. From an energetic perspective, the activation energy for cobalt, cobalt-molybdenum, and molybdenum was 115.2, 106.8, and 177.5 kJ mol⁻¹, respectively. With this evidence and considering the volcano shape described by the ammonia decomposition rate in relation to the metal composition ratio, the synergistic behavior of the system is clearly observed. However, since characterizations by XRD and TEM were inconclusive, the formation of intermetallic compounds should be still verified using HRTEM-EDS. From this point onwards, our objective is to incorporate parameters into the kinetic expressions that consider both compositional and structural elements and explore how these can maximize or influence H₂ production.

Keywords: CEDI, hydrogen carrier, LHHW, RDS

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Authors: Munawar Malik, Muntaha Ahmad, Khalil Ullah Khan

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Linguistic abilities in students with hearing impairment yet remain a concern for educationists. The emerging technological support and provisions in recent era vows to have addressed the situation and claims significant contribution in terms of linguistic repertoire. Being a descriptive and quantitative paradigm of study, the purpose of this research set forth was to assess linguistic competencies of students with hearing impairment in English language. The goals were further broken down to identify level of reading abilities in the subject population. The population involved students with HI studying at higher secondary level in Lahore. Simple random sampling technique was used to choose a sample of fifty students. A purposive curriculum-based assessment was designed in line with accelerated learning program by Punjab Government, to assess Linguistic competence among the sample. Further to it, an Informal Reading Inventory (IRI) corresponding to reading levels was also developed by researchers duly validated and piloted before the final use. Descriptive and inferential statistics were utilized to reach to the findings. Spearman’s correlation was used to find out relationship between degree of hearing loss, grade level, gender and type of amplification device. Independent sample t-test was used to compare means among groups. Major findings of the study revealed that students with hearing impairment exhibit significant deviation from the mean scores when compared in terms of grades, severity and amplification device. The study divulged that respective students with HI have yet failed to qualify an independent level of reading according to their grades as majority falls at frustration level of word recognition and passage comprehension. The poorer performance can be attributed to lower linguistic competence as it shows in the frustration levels of reading, writing and comprehension. The correlation analysis did reflect an improved performance grade wise, however scores could only correspond to frustration level and independent levels was never achieved. Reported achievements at instructional level of subject population may further to linguistic skills if practiced purposively.

Keywords: linguistic competence, hearing impairment, reading levels, educationist

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Authors: Keunhong Chae, Seokho Yoon

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We address a new integer frequency offset (IFO) estimation scheme with an aid of a pilot for orthogonal frequency division multiplexing systems. After correlating each continual pilot with a predetermined scattered pilot, the correlation value is again correlated to alleviate the influence of the timing offset. From numerical results, it is demonstrated that the influence of the timing offset on the IFO estimation is significantly decreased.

Keywords: estimation, integer frequency offset, OFDM, timing offset

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Authors: Puran Prasad Adhikari

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Considering the fact that when we are able to communicate science and economics effectively to broader nonprofessional audiences, it promotes a great understanding of its wider relevance to society and encourages more informed and confident decision-making at all levels, from the government to communities to individuals. The study has been conducted. This study is aimed to examine the understanding of the general public of economics and the basic sciences functioning in our surroundings in our day-to-day life. Data was gathered through historical documents related to science communication and through interviews with the public. The statistical result shows that there is a great lack of knowledge in the general public about the basic sciences and how economics impacts their life daily. The difficulties faced by the public include the view that these things can only be understood by professionals and it is beyond their capacity to grasp these concepts, the use of technical words and jargon by the professionals, and the lack of the medium to understand even if they want to learn it. The result further indicates that the lack of this basic knowledge also leads to bad decision-making, which causes frustration and anxiety. The result shows the great correlation between the confidence level of a person and the knowledge of basic science and economics. The factor behind this was the right decision-making capacity of the individual, which boosts the happy hormones of the individual. So indirectly, we found the correlation between mental health and the understanding of science and economics. The public wants to have a basic understanding and concepts of these topics, but they complain that there is no effective medium through which they can gain the understanding; the medium which is available is full of jargon and technical terms directed to professional and highly educated which they consider is beyond their reach. So, communicating the basic concepts to the general public is of great importance in the 21st century for the overall progress of society. The professional one can make this possible by considering the level of public understanding and making the communication and the programs comprehensible to the layman. Various means can be used to make this successful and effective, e.g., cartoon guide books, Q&A with the layman, animations use, and daily life examples. This study’s implication will help educators of high-level institutions and policymakers improve general public [layman] access to comprehensible knowledge.

Keywords: layman, comprehensible, decision making, frustration, confidence

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Authors: Soheila Zhaeentan, Anders Von Heijne, Elisabet Hagert, André Stark, Björn Salomonsson

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Recommended treatment for traumatic rotator cuff tear (TRCT) is surgery within a few weeks after injury if the diagnosis is made early, especially if a functional impairment of the shoulder exists. This may lead to the assumption that a poor outcome then can be expected in delayed surgical treatment, when the patient is diagnosed at a later stage. The aim of this study was to investigate if a surgical repair later than three months after injury may result in successful outcomes and patient satisfaction. There is evidence in literature that good results of treatment can be expected up to three months after the injury, but little is known of later treatment with cuff repair. 73 patients (75 shoulders), 58 males/17 females, mean age 59 (range 34-­‐72), who had undergone surgical intervention for TRCT between January 1999 to December 2011 at our clinic, were included in this study. Patients were assessed by MRI investigation, clinical examination, Western Ontario Rotator Cuff index (WORC), Oxford Shoulder Score, Constant-­‐Murley Score, EQ-­‐5D and patient subjective satisfaction at follow-­‐up. The patients treated surgically within three months ( < 12 weeks) after injury (39 cases) were compared with patients treated more than three months ( ≥ 12 weeks) after injury (36 cases). WORC was used as the primary outcome measure and the other variables as secondary. A senior consultant radiologist, blinded to patient category and clinical outcome, evaluated all MRI-­‐images. Rotator cuff integrity, presence of arthritis, fatty degeneration and muscle atrophy was evaluated in all cases. The average follow-­‐up time was 56 months (range 14-­‐149) and the average time from injury to repair was 16 weeks (range 3-­‐104). No statistically significant differences were found for any of the assessed parameters or scores between the two groups. The mean WORC score was 77 (early group, range 25-­‐ 100 and late group, range 27-­‐100) for both groups (p= 0.86), Constant-­‐Murley Score (p= 0.91), Oxford Shoulder Score (p= 0.79), EQ-­‐5D index (p= 0.86). Re-­‐tear frequency was 24% for both groups, and the patients with re-­‐tear reported less satisfaction with outcome. Discussion and conclusion: This study shows that surgical repair of TRCT performed later than three months after injury may result in good functional outcomes and patient satisfaction. However, this does not motivate an intentional delay in surgery when there is an indication for surgical repair as that delay may adversely affect the possibility to perform a repair. Our results show that surgeons may safely consider surgical repair even if a delay in diagnosis has occurred. A retrospective cohort study on 75 shoulders shows good functional result after traumatic rotator cuff tear (TRCT) treated surgically up to one year after the injury.

Keywords: traumatic rotator cuff injury, time to surgery, surgical outcome, retrospective cohort study

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Authors: S. Curteanu, F. Leon, M. Gavrilescu, S. A. Floria

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Optimization algorithms inspired from human behavior were applied in this approach, associated with neural networks models. The algorithms belong to human behaviors of learning and cooperation and human competitive behavior classes. For the first class, the main strategies include: random learning, individual learning, and social learning, and the selected algorithms are: simplified human learning optimization (SHLO), social learning optimization (SLO), and teaching-learning based optimization (TLBO). For the second class, the concept of learning is associated with competitiveness, and the selected algorithms are sports-inspired algorithms (with Football Game Algorithm, FGA and Volleyball Premier League, VPL) and Imperialist Competitive Algorithm (ICA). A real process, the synthesis of polyacrylamide-based multicomponent hydrogels, where some parameters are difficult to obtain experimentally, is considered as a case study. Reaction yield and swelling degree are predicted as a function of reaction conditions (acrylamide concentration, initiator concentration, crosslinking agent concentration, temperature, reaction time, and amount of inclusion polymer, which could be starch, poly(vinyl alcohol) or gelatin). The experimental results contain 175 data. Artificial neural networks are obtained in optimal form with biologically inspired algorithm; the optimization being perform at two level: structural and parametric. Feedforward neural networks with one or two hidden layers and no more than 25 neurons in intermediate layers were obtained with values of correlation coefficient in the validation phase over 0.90. The best results were obtained with TLBO algorithm, correlation coefficient being 0.94 for an MLP(6:9:20:2) – a feedforward neural network with two hidden layers and 9 and 20, respectively, intermediate neurons. Good results obtained prove the efficiency of the optimization algorithms. More than the good results, what is important in this approach is the simulation methodology, including neural networks and optimization biologically inspired algorithms, which provide satisfactory results. In addition, the methodology developed in this approach is general and has flexibility so that it can be easily adapted to other processes in association with different types of models.

Keywords: artificial neural networks, human behaviors of learning and cooperation, human competitive behavior, optimization algorithms

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Authors: Melissa Chavez Portillo, Hector Juarez Santiesteban, Mauricio Pacio Castillo, Oscar Portillo Moreno

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Nanocrystalline Li-doped PbS thin films have been deposited by chemical bath deposition technique. The goal of this work is to study the modification of the optoelectronic and structural properties of Lithium incorporation. The increase of Li doping in PbS thin films leads to an increase of band gap in the range of 1.4-2.3, consequently, quantum size effect becomes pronounced in the Li-doped PbS films, which lead to a significant enhancement in the optical band gap. Doping shows influence in the film growth and results in a reduction of crystallite size from 30 to 14 nm. The refractive index was calculated and a relationship with dielectric constant was investigated. The dc conductivities of Li-doped and undoped samples were measured in the temperature range 290-340K, the conductivity increase with increase of Lithium content in the PbS films.

Keywords: doping, quantum confinement, optical band gap, PbS

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Authors: Sorin Valcan, Mihail Gaianu

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Labeling is a very costly and time consuming process which aims to generate datasets for training neural networks in several functionalities and projects. For driver monitoring system projects, the need for labeled images has a significant impact on the budget and distribution of effort. This paper presents the modifications done to an algorithm used for the generation of ground truth data for 2D eyes location on infrared images with drivers in order to improve the quality of the data and performance of the trained neural networks. The algorithm restrictions become tougher, which makes it more accurate but also less constant. The resulting dataset becomes smaller and shall not be altered by any kind of manual label adjustment before being used in the neural networks training process. These changes resulted in a much better performance of the trained neural networks.

Keywords: labeling automation, infrared camera, driver monitoring, eye detection, convolutional neural networks

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Authors: Aboozar Aghaei

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In the present work, the dissimilar Monel400 and SS316 were joined by friction stir welding (FSW). The applied rotating speed was 400 rpm, whereas the traverse speed varied between 50 and 150 mm/min. At a constant rotating speed, the sound welds were obtained at the welding speeds of 50 and 100 mm/min. However, a groove-like defect was formed when the welding speed exceeded 100 mm/min. The mechanical properties of the joints were evaluated using tensile and fatigue tests. The fatigue strength of dissimilar FSWed specimens was higher than that of both Monel400 and SS316. To study the failure behavior of FSWed specimens, the fracture surfaces were analyzed using a scanning electron microscope (SEM). The failure analysis indicates that different mechanisms may contribute to the fracture of welds. This was attributed to the dissimilar characteristics of dissimilar materials exhibiting different failure behaviors.

Keywords: frictions stir welding (FSW), stainless steel, mechanical properties, Monel400

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Authors: Preetham Shankapal, Jill King, Kori Murray, Corby Martin, Paula Giselman, Jason Hicks, Owen Carmicheal

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Activation of reward and satiety networks in the brain while processing palatable food cues, as well as functional connectivity during rest has been studied using functional Magnetic Resonance Imaging of the brain in various obesity phenotypes. However, functional connectivity within the reward and satiety network during food cue processing is understudied. 14 obese individuals underwent two fMRI scans during viewing of Macronutrient Picture System images. Each scan included two blocks of images of High Sugar/High Fat (HSHF), High Carbohydrate/High Fat (HCHF), Low Sugar/Low Fat (LSLF) and also non-food images. Seed voxels within seven food reward relevant ROIs: Insula, putamen and cingulate, precentral, parahippocampal, medial frontal and superior temporal gyri were isolated based on a prior meta-analysis. Beta series correlation for task-related functional connectivity between these seed voxels and the rest of the brain was computed. Voxel-level differences in functional connectivity were calculated between: first and the second scan; individuals who saw novel (N=7) vs. Repeated (N=7) images in the second scan; and between the HC/HF, HSHF blocks vs LSLF and non-food blocks. Computations and analysis showed that during food image viewing, reward network ROIs showed significant functional connectivity with each other and with other regions responsible for attentional and motor control, including inferior parietal lobe and precentral gyrus. These functional connectivity values were heightened among individuals who viewed novel HS/HF images in the second scan. In the second scan session, functional connectivity was reduced within the reward network but increased within attention, memory and recognition regions, suggesting habituation to reward properties and increased recollection of previously viewed images. In conclusion it can be inferred that Functional Connectivity within reward network and between reward and other brain regions, varies by important experimental conditions during food photography viewing, including habituation to shown foods.

Keywords: fMRI, functional connectivity, task-based, beta series correlation

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Authors: N. Hiranmai, M. L. S. Deva Kumar

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In this project, it is planned to carry out an experimental investigation on 4- stroke Direct Injection Diesel Engine, which is a single-cylinder, four-stroke, water-cooled, and constant speed engine capable of developing a power output of 3.7 kW at 1500 rpm, run with diesel fuel and also with different proportions of Safflower oil methyl esters, with a piston having five number of grooves on its crown to create turbulence. Various performance parameters, such as brake power, specific fuel consumption, and thermal efficiency, are calculated. At all the load conditions, the performance of the engine is obtained better for blend B40 (40% Safflower oil + 60% of Diesel). At different load conditions, Brake thermal Efficiency (ηbth) is comparatively more for all blends than that for Diesel. At different load conditions, ηith is less for blend B40.

Keywords: four-stroke engine, diesel, safflower oil, engine performance, emissions.

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Authors: Katalin Szöllősi, László Szabó

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Introduction and purpose: Even though female sexual dysfunctions are common among women in the postpartum period, the profile of these disturbances has not been well investigated in Hungary yet. The aim of the study was to evaluate the postpartum female sexual functions in Hungary. This research sought to investigate the possible predictor factors which can influence postpartum female sexual functions. Method and sample: This was a cross-sectional study, including patients from two maternity clinics in Budapest. 113 women were recruited into our study 3 months after their childbirth. 53 had vaginal birth, 60 had a caesarian section. Data were collected from medical reports in addition by using self-developed questions and validated questionnaires in order to measure important predictors which may be responsible for postpartum sexual dysfunctions such as mode of delivery, parity, urinary incontinence and body image. Sexual functions were evaluated by the Hungarian version of the Female Sexual Function Index (FSFI). The Hungarian version of Body Image Questionnaire-Short Form14 (BSQ-SF14) was applied for assessing body image. Results: 82,3% of the participants began to have sexual intercourse within three months postpartum. 53,98% of the participants reported sexual dysfunctions (cut-off FSFI score 26,55). According to our results mode of delivery, parity, hemorrhoids, time of intercourse, resumption was not associated with female sexual dysfunctions. We found correlation at a tendential level between urinary incontinence and sexual dysfunctions (p=0,003, R=0,26). We found a negative correlation at a tendential level between the total score of BSQ-SF14 and FSFI (p=0,03, R=-0,269). Only 32,74% of women reported discussing sexual life with health care professionals. However, 67,25% of them would have had the need to be asked about their postpartum health issues. Conclusions and recommendations: The prevalence of female sexual dysfunctions were relatively high after childbirth. We found that incontinence and body image was associated with sexual dysfunctions; other risk factors remained unknown. Despite regular contact with health care professionals, women rarely get any information about postpartum sexual health issues. The high prevalence of dysfunctions indicates the need for further investigation to address other risk factors and proper counselling of women after childbirth.

Keywords: body image, postpartum, sexual dysfunction, urinary incontinence

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Authors: Waqas Ali

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Concrete is broadly used as a structural material in the construction of buildings. When the concrete is exposed to elevated temperature, its strength evaluation is very necessary in the existing structure. In this study, the effect of temperature and the reliability of the core test has been evaluated. For this purpose, the cylindrical cores were extracted from High strength concrete (HSC) specimens that were exposed to the temperature ranging from 300 ℃ to 900 ℃ with a constant duration of 4 hr. This study compares the difference between the standard heated cylinders and the cores taken from them after curing of 90 days. The difference of cylindrical control and binary mix samples and extracted cores revealed that there is 12.19 and 12.38% difference at 300℃, while this difference was found to increase up to 12.89%, 13.03% at 500 ℃. Furthermore, this value is recorded as 12.99%, 13.57% and 14.40%, 14.38% at 700 ℃ and 900 ℃, respectively. A total of four equations were developed through a regression model for the prediction of the strength of concrete for both standard cylinders and extracted cores whose R square values were 0.9733, 0.9627 and 0.9473, 0.9452, respectively.

Keywords: high strength, temperature, core, reliability

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Authors: Marwa Mamdouh Shaban, Nagat Saied Habib, Shireen Ezz El-Din Taha, Eman Mahmoud Seif El-Naser

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Background: Dental nurses and dentists were constantly exposed to a number of specific work related health risk factors which develop and intensify with years. Awareness regarding these work-related health risk factors and implementation of preventive health care measures could provide a safe work environment for all dental nurses and dentists. Aim of the study: to assess the work-related health risk factors among dental nurses and dentists and preventive health care measures applied among dental nurses and dentists. Research design: A descriptive design was utilized. Sample: Convenience sample of 50 dental nurses and 150 dentists were included in the current study. Setting: This study was conducted at the dental clinics at faculty of oral and dental medicine, Al-Kasr Al Ainy Hospital. Tools of data collection: Three tools were developed, tested for clarity, and feasibility: a-Socio-demographic data sheet, b-Work-related health risk factors questionnaire, and c-structured observational checklist. Results: The most common work risk factors prevailing among dental nurses were emotional exhaustion (82%), low back pain (76%) and latex allergy (62%) and the most common work risk factors prevailing among dentists were percutaneous exposure incident (100%), emotional exhaustion (100%) and low back pain (93.3%). Also, statistically significant negative correlation (r=-0.274, at p = 0.045) between the incidence of chemical health risk factors and application of chemical preventive measures among dental nurses. A statistically significant negative correlation (r=-0.177, at p = 0.030) between the incidences of mechanical health risk factors among dentists and application of mechanical preventive measures. Conclusion: The studied dental nurses and dentists exposed to many work related health risk factors as latex allergy, percutaneous exposure incidents, low back pain and emotional exhaustion related to inappropriate application of preventive health care measures. Recommendation: Raise awareness of dental nurses and dentists about work-related health risk factors, design and implement health education program for preventive health care measures.

Keywords: work-related risk factors, preventive measures, nurses, dentists

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Authors: Milica Lazic, Jovana Jestrovic

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The aim of this research is to examine moderating role of positive and negative affect, defined as traits, in relationship between a number of stressful life events to which an individual is exposed and life satisfaction. The tendency to experience positive and negative emotions is considered as relatively independent, and life satisfaction depends on presence and intensity of emotions of different valence. However, the role of positive and negative affect can be much more complex. It can change the direction and/or intensity of correlation between a number of stressful life events and life satisfaction. Thus, this question is important for two reasons, (I) better comprehension of inconsistent result of correlation intensity between stressful events and life satisfaction (II) verification on what conditions positive and negative affect have a protective role, and on what conditions the positive and/or negative affect is vulnerability factor. Longitudinal data were collected in two waves from 660 adolescents. Firstly, participants completed the Positive and Negative Affect Schedule. A year later, Life events questionnaire, which measures the number of stressful events in the past six months and Satisfaction with Life Scale were administered. The data were analyzed using hierarchical regression analyses: three-way interaction. The results show that number of life events, positive and negative effect contribute to the level of life satisfaction. The check of moderation role shows the significant three-way interaction of number of life event, and both, positive and negative affect. Individuals who report high level of positive affect, estimate to be moderate to highly satisfied with their lives, regardless of number of stressors to which they are exposed and also how often they experience negative emotions. Individuals, who often experience negative emotions and rarely positive, report the lowest level of life satisfaction. It doesn't change despite the number of stressors they were exposed to. Individuals who report that rarely experience not only positive than also negative emotions estimate different level of life satisfaction depending on number of stressors they were exposed to. Under the influence of numerous stressors, their level of life satisfaction is low, and it's equal to life satisfaction level of individuals who often experience negative and rarely positive emotions. The result of this research shows that tendency to often experience positive emotions is the protective factor in situation when individuals are exposed to high number of stressors. On the other hand, tendency to rarely experience positive emotions present vulnerability factor. Conclusions and practical implications are further discussed.

Keywords: life events, life satisfaction, subjective well-being, positive and negative affect

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Authors: Asma Ben Yaghlane, Mohamed Naceur Azaiez

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In this paper, we treat a model that falls in the area of protecting targeted systems from intelligent threats including terrorism. We introduce the concept of system survivability, in the context of continuous attacks, as the probability that a system under attack will continue operation up to some fixed time t. We define a constant attack rate (CAR) process as an attack on a targeted system that follows an exponential distribution. We consider the superposition of several CAR processes. From the attacker side, we determine the optimal attack strategy that minimizes the system survivability. We also determine the optimal strengthening strategy that maximizes the system survivability under limited defensive resources. We use operations research techniques to identify optimal strategies of each antagonist. Our results may be used as interesting starting points to develop realistic protection strategies against intentional attacks.

Keywords: CAR processes, defense/attack strategies, exponential failure, survivability

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Authors: Dávid Kovács, Bálint Csanády, Dániel Boros, Iván Ivkovic, Lóránt Nagy, Dalma Tóth-Lakits, László Márkus, András Lukács

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The modeling practice of financial instruments has seen significant change over the last decade due to the recognition of time-dependent and stochastically changing correlations among the market prices or the prices and market characteristics. To represent this phenomenon, the Stochastic Correlation Process (SCP) has come to the fore in the joint modeling of prices, offering a more nuanced description of their interdependence. This approach has allowed for the attainment of realistic tail dependencies, highlighting that prices tend to synchronize more during intense or volatile trading periods, resulting in stronger correlations. Evidence in statistical literature suggests that, similarly to the volatility, the SCP of certain stock prices follows rough paths, which can be described using fractional differential equations. However, estimating parameters for these equations often involves complex and computation-intensive algorithms, creating a necessity for alternative solutions. In this regard, the Fractional Ornstein-Uhlenbeck (fOU) process from the family of fractional processes offers a promising path. We can effectively describe the rough SCP by utilizing certain transformations of the fOU. We employed neural networks to understand the behavior of these processes. We had to develop a fast algorithm to generate a valid and suitably large sample from the appropriate process to train the network. With an extensive training set, the neural network can estimate the process parameters accurately and efficiently. Although the initial focus was the fOU, the resulting model displayed broader applicability, thus paving the way for further investigation of other processes in the realm of financial mathematics. The utility of SCP extends beyond its immediate application. It also serves as a springboard for a deeper exploration of fractional processes and for extending existing models that use ordinary Wiener processes to fractional scenarios. In essence, deploying both SCP and fractional processes in financial models provides new, more accurate ways to depict market dynamics.

Keywords: fractional Ornstein-Uhlenbeck process, fractional stochastic processes, Heston model, neural networks, stochastic correlation, stochastic differential equations, stochastic volatility

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Authors: Linara Salikhova, Elmira Nizamova, Aleksandra Katasonova, Gleb Vitkov, Olga Sarapulova.

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While most European cities conduct research on heat-related risks, there is a research gap in the Caucasus region, particularly in Yerevan, Armenia. This study aims to test the method of establishing a correlation between urban heat islands (UHI) and urban greenery distribution for prioritization of heat-vulnerable areas for revegetation. Armenia has failed to consider measures to mitigate UHI in urban development strategies despite a 2.1°C increase in average annual temperature over the past 32 years. However, planting vegetation in the city is commonly used to deal with air pollution and can be effective in reducing UHI if it prioritizes heat-vulnerable areas. The research focuses on establishing such priorities while considering the distribution of urban greenery across the city. The lack of spatially explicit air temperature data necessitated the use of satellite images to achieve the following objectives: (1) identification of land surface temperatures (LST) and quantification of temperature variations across districts; (2) classification of massifs of land surface types using normalized difference vegetation index (NDVI); (3) correlation of land surface classes with LST. Examination of the heat-vulnerable city areas (in this study, the proportion of individuals aged 75 years and above) is based on demographic data (Census 2011). Based on satellite images (Sentinel-2) captured on June 5, 2021, NDVI calculations were conducted. The massifs of the land surface were divided into five surface classes. Due to capacity limitations, the average LST for each district was identified using one satellite image from Landsat-8 on August 15, 2021. In this research, local relief is not considered, as the study mainly focuses on the interconnection between temperatures and green massifs. The average temperature in the city is 3.8°C higher than in the surrounding non-urban areas. The temperature excess ranges from a low in Norq Marash to a high in Nubarashen. Norq Marash and Avan have the highest tree and grass coverage proportions, with 56.2% and 54.5%, respectively. In other districts, the balance of wastelands and buildings is three times higher than the grass and trees, ranging from 49.8% in Quanaqer-Zeytun to 76.6% in Nubarashen. Studies have shown that decreased tree and grass coverage within a district correlates with a higher temperature increase. The temperature excess is highest in Erebuni, Ajapnyak, and Nubarashen districts. These districts have less than 25% of their area covered with grass and trees. On the other hand, Avan and Norq Marash districts have a lower temperature difference, as more than 50% of their areas are covered with trees and grass. According to the findings, a significant proportion of the elderly population (35%) aged 75 years and above reside in the Erebuni, Ajapnyak, and Shengavit neighborhoods, which are more susceptible to heat stress with an LST higher than in other city districts. The findings suggest that the method of comparing the distribution of green massifs and LST can contribute to the prioritization of heat-vulnerable city areas for revegetation. The method can become a rationale for the formation of an urban greening program.

Keywords: heat-vulnerability, land surface temperature, urban greenery, urban heat island, vegetation

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Authors: Mostafa Shahriari, Sergio Rojas, David Pardo, Angel Rodriguez- Rozas, Shaaban A. Bakr, Victor M. Calo, Ignacio Muga

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Logging-While Drilling (LWD) is a technique to record down-hole logging measurements while drilling the well. Nowadays, LWD devices (e.g., nuclear, sonic, resistivity) are mostly used commercially for geo-steering applications. Modern borehole resistivity tools are able to measure all components of the magnetic field by incorporating tilted coils. The depth of investigation of LWD tools is limited compared to the thickness of the geological layers. Thus, it is a common practice to approximate the Earth’s subsurface with a sequence of 1D models. For a 1D model, we can reduce the dimensionality of the problem using a Hankel transform. We can solve the resulting system of ordinary differential equations (ODEs) either (a) analytically, which results in a so-called semi-analytic method after performing a numerical inverse Hankel transform, or (b) numerically. Semi-analytic methods are used by the industry due to their high performance. However, they have major limitations, namely: -The analytical solution of the aforementioned system of ODEs exists only for piecewise constant resistivity distributions. For arbitrary resistivity distributions, the solution of the system of ODEs is unknown by today’s knowledge. -In geo-steering, we need to solve inverse problems with respect to the inversion variables (e.g., the constant resistivity value of each layer and bed boundary positions) using a gradient-based inversion method. Thus, we need to compute the corresponding derivatives. However, the analytical derivatives of cross-bedded formation and the analytical derivatives with respect to the bed boundary positions have not been published to the best of our knowledge. The main contribution of this work is to overcome the aforementioned limitations of semi-analytic methods by solving each 1D model (associated with each Hankel mode) using an efficient multi-scale finite element method. The main idea is to divide our computations into two parts: (a) offline computations, which are independent of the tool positions and we precompute only once and use them for all logging positions, and (b) online computations, which depend upon the logging position. With the above method, (a) we can consider arbitrary resistivity distributions along the 1D model, and (b) we can easily and rapidly compute the derivatives with respect to any inversion variable at a negligible additional cost by using an adjoint state formulation. Although the proposed method is slower than semi-analytic methods, its computational efficiency is still high. In the presentation, we shall derive the mathematical variational formulation, describe the proposed multi-scale finite element method, and verify the accuracy and efficiency of our method by performing a wide range of numerical experiments and comparing the numerical solutions to semi-analytic ones when the latest are available.

Keywords: logging-While-Drilling, resistivity measurements, multi-scale finite elements, Hankel transform

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Authors: Prateek Kishore, T. M. Muruganandam

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Supersonic wind tunnel nozzles are generally capable of producing a constant Mach number flow in the test section of the wind tunnel. As a result, most of the supersonic vehicles are widely designed using steady state flow characteristics which may have errors while facing unsteady situations. This study aims to explore the possibility of varying the Mach number of the flow during wind tunnel operation. The nozzle walls are restricted to be inflexible for cooling near the throat due to high stagnation temperature requirement of the flow to simulate the conditions as experienced by the vehicle. Two simple independent mechanisms, rotation and translation of nozzle walls have been analyzed and the nozzle ranges have been optimized to vary the Mach number from Mach 2 to Mach 5 using minimum number of nozzles in the wind tunnel.

Keywords: method of characteristics, nozzle, supersonic wind tunnel, variable mach number

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Authors: Nana Weng

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From 2008, Chinese Foreign Direct Investment flows to the European Union continued its rapid rise. Currently, the industrial structure adjustment in developing countries has also been placed on the international movement of factors of production. Now China economy is in an important period of transformation on industrial structure adjustment. Under the international transfer of industry background, the adjustment of industrial structure upgrading and sophistication are the key elements of a successful economic transformation. In order to achieve a virtuous cycle of foreign investment patterns and optimize the industrial structure of foreign direct investment as well, the research on the positive the role of the EU direct investment and how it impact China’s industrial structure optimization and upgrading is of great significance. In this paper, the author explained how the EU as an investment destination is different with the United States and ASEAN. Then, based on the theory of FDI and industrial structure and combining the four kinds of motives of China’s ODI in EU, this paper explained the impact mechanism which has influenced China domestic industrial structure primarily through the Transfer effect, Correlation effect and Competitive effect. On the premise that FDI activities do affect the home country’s domestic industrial structure, this paper made empirical analysis with industrial panel data. With the help of Gray Correlation Method and Limited Distributed Lags, this paper found that China/s ODI in the EU impacted the tertiary industry strongly and had a significant positive impact, particularly the manufacturing industry and the financial industry. This paper also pointed out that Chinese MNEs should realize several issues, such as pay more attention to high-tech industries so that they can make the best use of reverse technology spillover. When Chinese enterprises ‘go out,' they ought to keep in mind that domestic research and development capital contribution can make greater economic growth. Finally, based on theoretical and empirical analysis results, this paper presents the industry choice recommendations in the future of the EU direct investment, particularly through the development of the proper rational industrial policy and industrial development strategic to guide the industrial restructuring and upgrading.

Keywords: china ODI in european union, industrial structure optimization, impact mechanism, empirical analysis

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