Search results for: double trans-obturator technique (TOT)

Authors: Mohanad Alhabo, Li Zhang, Naveed Nawaz

Abstract:

In this paper, a non-cooperative game method is formulated where all players compete to transmit at higher power. Every base station represents a player in the game. The game is solved by obtaining the Nash equilibrium (NE) where the game converges to optimality. The proposed method, named Power Efficient Handover Game Theoretic (PEHO-GT) approach, aims to control the handover in dense small cell networks. Players optimize their payoff by adjusting the transmission power to improve the performance in terms of throughput, handover, power consumption and load balancing. To select the desired transmission power for a player, the payoff function considers the gain of increasing the transmission power. Then, the cell selection takes place by deploying Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS). A game theoretical method is implemented for heterogeneous networks to validate the improvement obtained. Results reveal that the proposed method gives a throughput improvement while reducing the power consumption and minimizing the frequent handover.

Keywords: energy efficiency, game theory, handover, HetNets, small cells

Procedia PDF Downloads 127

Authors: Arseniy M. Kondratyev, Sergey V. Onufriev, Alexander I. Savvatimskiy

Abstract:

The microsecond electrical pulse heating technique which provides uniform energy input into an investigated specimen is considered. In the present study we investigated ZrC+C carbide specimens in a form of a thin layer (about 5 microns thick) that were produced using a method of magnetron sputtering on insulating substrates. Specimens contained (at. %): Zr–17.88; C–67.69; N–8.13; O–5.98. Current through the specimen, voltage drop across it and radiation at the wavelength of 856 nm were recorded in the experiments. It enabled us to calculate the input energy, specific heat (from 2300 to 4500 K) and resistivity (referred to the initial dimensions of a specimen). To obtain the true temperature a black body specimen was used. Temperature of the beginning and completion of a phase transition (solid–liquid) was measured.Temperature of the onset of melting was 3150 K at the input energy 2.65 kJ/g; temperature of the completion of melting was 3450 K at the input energy 5.2 kJ/g. The specific heat of the solid phase of investigated carbide calculated using our data on temperature and imparted energy, is close to 0.75 J/gК for temperature range 2100–2800 K. Our results are considered together with the equilibrium Zr-C phase diagram.

Keywords: pulse heating, zirconium carbide, high temperatures, melting

Procedia PDF Downloads 323

Authors: Negar Riazifar, Nigel G. Stocks

Abstract:

This paper proposes strategies in level crossing (LC) sampling and reconstruction that provide high fidelity signal reconstruction for speech signals; these strategies circumvent the problem of exponentially increasing number of samples as the bit-depth is increased and hence are highly efficient. Specifically, the results indicate that the distribution of the intervals between samples is one of the key factors in the quality of signal reconstruction; including samples with short intervals do not improve the accuracy of the signal reconstruction, whilst samples with large intervals lead to numerical instability. The proposed sampling method, termed reduced conventional level crossing (RCLC) sampling, exploits redundancy between samples to improve the efficiency of the sampling without compromising performance. A reconstruction technique is also proposed that enhances the numerical stability through linear interpolation of samples separated by large intervals. Interpolation is demonstrated to improve the accuracy of the signal reconstruction in addition to the numerical stability. We further demonstrate that the RCLC and interpolation methods can give useful levels of signal recovery even if the average sampling rate is less than the Nyquist rate.

Keywords: level crossing sampling, numerical stability, speech processing, trigonometric polynomial

Procedia PDF Downloads 146

Authors: Melek Tufan, Filiz Erden, E. Elhan Özus

Abstract:

Apparel is a fact that has assigned wide cultural functions in development process even if it basically aims at protection during mankind's cultural development and course of live. It is an important cultural element that has been shaped by ecological conditions, social and personal values, traditions, cultural and economic conditions, at the same time it is a bearer of culture. Customs and traditions that maintain culture create differences in dressing styles of the region. These differences create traditional clothing forms specific to each region, which are different from each other or show close similarities. Differences which have dominant features create sense of dress specific to community owned. Samples of a kind of dress worn over salwar, long shirt, jacket, salwar and underpants that are types of local female dresses available in houses of yuruk community in Günaydın village of Balıkesir region have been found. By examining local dresses in terms of material, color, cutting, sewing, ornamentation technique and ornamentation subject and it has been aimed to record them with observation forms and transfer them to the next generations.

Keywords: women, traditional, Turkish Culture, art, fashion

Procedia PDF Downloads 340

Authors: Pankhuri Bansal, Sanjeev Kumar

Abstract:

We examined the exotic role of electrical poling of layered BCZT-NZFO bulk composite for sustainable advancement of magnetoelectric (ME) technology. Practically, it seems quite difficult to access the full potential of ME composites due to their weak ME coupling performances. Using a standard poling protocol, we successfully deployed the coupling performance of laminated ME composite, comprised of a ferroelectric (FE) layer of BCZT and a ferrite layer of NZFO. However, the ME coupling constant of laminated composite is optimized by lowering the volume fraction of the FE component to strengthen the mechanical strain in the piezoelectric layer while fixing the thickness of the magnetostrictive ferrite layer. Here, we employed systematic zero field cooled (ZFC) and field cooled (FC) electrical poling protocol on morphotropic phase boundary (MPB) based BCZT composition, well-appreciated for it’s remarkable electromechanical activity. We report a record augmentation in magnetoelectric coupling as a consequence of a prudent field-cooled poling mechanism. On the basis of our findings, we emphasize that the degree of magnetoelectricity may be significantly improved for the miniaturization of efficient devices via proper execution of the poling technique.

Keywords: magnetoelectric, lead-free, ferroelctric, ferromagnetic, energy harvesting

Procedia PDF Downloads 43

Authors: Mehdi Soula, Yosra Mani, Estelle Saras, Antoine Drapeau, Raoudha Grami, Mahjoub Aouni, Jean-Yves Madec, Marisa Haenni, Wejdene Mansour

Abstract:

Multi-resistance to antibiotics in gram-negative bacilli and particularly in enterobacteriaceae, has become frequent in hospitals in Tunisia. However, data on antibiotic resistant bacteria in aquatic products are scarce. The aims of this study are to estimate the proportion of ESBL- and carbapenemase-producing Enterobacterales in seafood (clams and fish) in Tunisia and to molecularly characterize the collected isolates. Two types of seafood were sampled in unrelated markets in four different regions in Tunisia (641 pieces of farmed fish and 1075 mediterranean clams divided into 215 pools, and each pool contained 5 pieces). Once purchased, all samples were incubated in tubes containing peptone salt broth for 24 to 48h at 37°C. After incubation, overnight cultures were isolated on selective MacConkey agar plates supplemented with either imipenem or cefotaxime, identified using API20E test strips (bioMérieux, Marcy-l’Étoile, France) and confirmed by Maldi-TOF MS. Antimicrobial susceptibility was determined by the disk diffusion method on Mueller-Hinton agar plates and results were interpreted according to CA-SFM 2021. ESBL-producing Enterobacterales were detected using the Double Disc Synergy Test (DDST). Carbapenem-resistance was detected using an ertapenem disk and was respectively confirmed using the ROSCO KPC/MBL and OXA-48 Confirm Kit (ROSCO Diagnostica, Taastrup, Denmark). DNA was extracted using a NucleoSpin Microbial DNA extraction kit (Macherey-Nagel, Hoerdt, France), according to the manufacturer’s instructions. Resistance genes were determined using the CGE online tools. The replicon content and plasmid formula were identified from the WGS data using PlasmidFinder 2.0.1 and pMLST 2.0. From farmed fishes, nine ESBL-producing strains (9/641, 1.4%) were isolated, which were identified as E. coli (n=6) and K. pneumoniae (n=3). Among the 215 pools of 5 clams analyzed, 18 ESBL-producing isolates were identified, including 14 E. coli and 4 K. pneumoniae. A low isolation rate of ESBL-producing Enterobacterales was detected 1.6% (18/1075) in clam pools. In fish, the ESBL phenotype was due to the presence of the blaCTX-M-15 gene in all nine isolates, but no carbapenemase gene was identified. In clams, the predominant ESBL phenotype was blaCTX-M-1 (n=6/18). blaCPE (NDM1, OXA48) was detected only in 3 isolates ‘K. pneumoniae isolates’. Replicon typing on the strains carring the ESBL and carbapenemase gene revelead that the major type plasmid carried ESBL were IncF (42.3%) [n=11/26]. In all, our results suggest that seafood can be a reservoir of multi-drug resistant bacteria, most probably of human origin but also by the selection pressure of antibiotic. Our findings raise concerns that seafood bought for consumption may serve as potential reservoirs of AMR genes and pose serious threat to public health.

Keywords: BLSE, carbapenemase, enterobacterales, tunisian seafood

Procedia PDF Downloads 108

Authors: Nathenal Thomas Lambamo

Abstract:

Based on the fact that more than 85% of the labor force and 90% of the export earnings are taken by agriculture in Ethiopia and it can be said that it is the backbone of the overall socio-economic activities in the country. Among the cereal crops that the agriculture sector provides for the country, wheat is the third-ranking one preceding teff and maize. In the present day, wheat is in higher demand related to the expansion of industries that use them as the main ingredient for their products. The local supply of wheat for these companies covers only 35 to 40% and the rest 60 to 65% percent is imported on behalf of potential customers that exhaust the country’s foreign currency reserves. The above facts show that the need for this crop in the country is too high and in reverse, the productivity of the crop is very less because of these reasons. Wheat disease is the most devastating disease that contributes a lot to this unbalance in the demand and supply status of the crop. It reduces both the yield and quality of the crop by 27% on average and up to 37% when it is severe. This study aims to detect the most frequent and degrading wheat diseases, Septoria and Leaf rust, using the most efficiently used subset of machine learning technology, deep learning. As a state of the art, a deep learning class classification technique called Convolutional Neural Network (CNN) has been used to detect diseases and has an accuracy of 99.01% is achieved.

Keywords: septoria, leaf rust, deep learning, CNN

Procedia PDF Downloads 76

Authors: M. Pacio, H. Juárez, R. Pérez-Cuapio E. Rosendo, T. Díaz, G. García

Abstract:

In this study, zinc oxide (ZnO) quantum dots (QDs) have been prepared by a simple route. The growth parameters for ZnO QDs were systematically studied inside a SiO2 shell; this shell acts as a capping agent and also enhances stability of the nanoparticles in water. ZnO QDs in silica shell could be produced by initially synthesizing a ZnO colloid (containing ZnO nanoparticles in methanol solution) and then was mixed with 3-aminopropylsiloxane used as SiO2 precursor. ZnO QDs were deposited onto silicon substrates (100) orientation by spin-coating technique. ZnO QDs into a SiO2 shell were pre-heated at 300 °C for 10 min after each coating, that procedure was repeated five times. The films were subsequently annealing in air atmosphere at 500 °C for 2 h to remove the trapped fluid inside the amorphous silica cage. ZnO QDs showed hexagonal wurtzite structure and about 5 nm in diameter. The composition of the films at the surface and in the bulk was obtained by Secondary Ion Mass Spectrometry (SIMS), the spectra revealed the presence of Zn- and Si- related clusters associated to the chemical species in the solid matrix. Photoluminescence (PL) spectra under 325 nm of excitation only show a strong UV emission band corresponding to ZnO QDs, such emission is enhanced with annealing. Our results showed that the method is appropriate for the preparation of ZnO QDs films embedded in a SiO2 shell with high UV photoluminescence.

Keywords: ZnO QDs, sol gel, functionalization

Procedia PDF Downloads 433

Authors: Tarek Duzan, Walid Eddib

Abstract:

The marine shallow carbonate reservoir (G- Eocene) is one of the biggest mature water drive reservoir of Waha Oil Company. The cumulative oil produced up to date is about to eighty percent of the booked original oil in place at ninety five percent of Water cut. However, the company believes that there is a good amount of remaining oil left need to be recovered. Many laboratory studies have been conducted to see the possibility drain the commercial oil left behind using two types of gases, namely, carbone dioxide and enriched hydrocarbon gas injection. The conclusions of those cases were inconclusive Technically and Economically. Therefore, the company has decided to verify another Tertiary Recovery (EOR) technique that may be applied to the interested reservoir. A global screening criteria and quick Laboratory chemical tests have been conducted by using many types of chemical injection into real rock samples. The outcomes were unique economically and provide a significant increase in the commercial oil left. Finally, the company has started conducting a sector pilot plan before proceeding with a full plan. There are many wellbores available to use in a potential field Enhanced Oil Recovery.

Keywords: chemical lab. test, ASP, rock types, oil samples, and global screening criteria

Procedia PDF Downloads 138

Authors: Billel Kenidra, Mohamed Benmohammed

Abstract:

Data mining technique used in the field of clustering is a subject of active research and assists in biological pattern recognition and extraction of new knowledge from raw data. Clustering means the act of partitioning an unlabeled dataset into groups of similar objects. Each group, called a cluster, consists of objects that are similar between themselves and dissimilar to objects of other groups. Several clustering methods are based on partitional clustering. This category attempts to directly decompose the dataset into a set of disjoint clusters leading to an integer number of clusters that optimizes a given criterion function. The criterion function may emphasize a local or a global structure of the data, and its optimization is an iterative relocation procedure. The K-Means algorithm is one of the most widely used partitional clustering techniques. Since K-Means is extremely sensitive to the initial choice of centers and a poor choice of centers may lead to a local optimum that is quite inferior to the global optimum, we propose a strategy to initiate K-Means centers. The improved K-Means algorithm is compared with the original K-Means, and the results prove how the efficiency has been significantly improved.

Keywords: microarray data mining, biological pattern recognition, partitional clustering, k-means algorithm, centroid initialization

Procedia PDF Downloads 190

Authors: Nida Amin, Fahad Tanveer, Hina Shabbir, Ayesha Saeed, Attiqa Riaz

Abstract:

The gradual progression of corneal disorder keratoconus significantly impairs eyesight and quality of life, increasing the likelihood of depression. Using the Hospital Anxiety and Depression Scale (HADS) at the AL-Ibrahim Eye Hospital in Karachi, this study aimed to evaluate the occurrence of depression and anxiety symptoms in patients with keratoconus and to suggest better treatment. A descriptive-analytical study was conducted at Al-Ibrahim Eye Hospital Karachi from March to April 2022, and patients diagnosed with symptomatic keratoconus were recruited using a non-probability convenient sampling technique. After obtaining written informed consent from patients, keratoconus severity was assessed using visual acuity and corneal topography. Symptoms of anxiety and depression were assessed using the Hospital Anxiety and Depression (HADS) Scale. The data were analyzed using SPSS version 20.0. Spearman correlation coefficient. Of the 108 participants, 60 (56%) were female and 48 (44%) were male. Using the HADS scale, 44 (40.7%) patients were classified as normal with a HADS score of (0-7), 23 (21.3%) as borderline with a HADS score of (8-10) and 41 (38%) patients were diagnosed with anxiety and depression with a HADS score of (11-21). Depression and anxiety are highly prevalent among patients in advanced stages of the disease.

Keywords: cornea, keratoconus, anxiety, depression, corneal topography, mental health

Procedia PDF Downloads 35

Authors: Axel Thallemer, Martin Danzer, Dominik Diensthuber, Aleksandar Kostadinov, Bernhard Rogler

Abstract:

Nature has always inspired the creative mind, to a lesser or greater extent. Introduced around the 1950s, Biomimetics served as a systematic method to treat the natural world as a ‘pattern book’ for technical solutions with the aim to create innovative products. Unfortunately, this technique is prone to failure when performed as a mere reverse engineering of a natural system or appearance. Contrary to that, a solution which looks at the principles of a natural design, promises a better outcome. One such example is the here presented case study, which shows the design process of three distinctive grippers. The devices have biomimetic properties on two levels. Firstly, they use a kinematic chain found in beaks and secondly, they have a biomimetic structural geometry, which was realized using additive manufacturing. In a next step, the manufacturing method was evaluated to estimate its efficiency for commercial production. The results show that the fabrication procedure is still in its early stage and thus it is not able to guarantee satisfactory results. To summarize the study, we claim that a novel solution can be derived using principles from nature, however, for the solution to be actualized successfully, there are parameters which are beyond reach for designers. Nonetheless, industrial designers can contribute to product innovation using biomimetics.

Keywords: biomimetics, innovation, design process, additive manufacturing

Procedia PDF Downloads 191

Authors: Emiliya Tsankova, Genoveva Zlateva, Violeta Kostadinova

Abstract:

The challenges modern education faces undoubtedly require reforms and innovations aimed at the reconceptualization of existing educational strategies, the introduction of new concepts and novel techniques and technologies related to the recasting of the aims of education and the remodeling of the content and methodology of education which would guarantee the streamlining of our education with basic European values. Aim: The aim of the current research is the development of a didactic technology for the assessment of the applicability and efficacy of game techniques in pedagogic practice calibrated to specific content and the age specificity of learners, as well as for evaluating the efficacy of such approaches for the facilitation of the acquisition of biological knowledge at a higher theoretical level. Results: In this research, we examine the objectivity, reliability and validity of two newly introduced diagnostic parameters for assessing the durability of the acquired knowledge. A pedagogic experiment has been carried out targeting the verification of the hypothesis that the introduction of game techniques in biological education leads to an increase in the quantity, quality and durability of the knowledge acquired by students. For the purposes of monitoring the effect of the application of the pedagogical technique employing game methodology on the durability of the acquired knowledge a test-base examination has been applied to students from a control group (CG) and students form an experimental group on the same content after a six-month period. The analysis is based on: 1.A study of the statistical significance of the differences of the tests for the CG and the EG, applied after a six-month period, which however is not indicative of the presence or absence of a marked effect from the applied pedagogic technique in cases when the entry levels of the two groups are different. 2.For a more reliable comparison, independently from the entry level of each group, another “indicator of efficacy of game techniques for the durability of knowledge” which has been used for the assessment of the achievement results and durability of this methodology of education. The monitoring of the studied parameters in their dynamic unfolding in different age groups of learners unquestionably reveals a positive effect of the introduction of game techniques in education in respect of durability and permanence of acquired knowledge. Methods: In the current research the following battery of methods and techniques of research for diagnostics has been employed: theoretical analysis and synthesis; an actual pedagogical experiment; questionnaire; didactic testing and mathematical and statistical methods. The data obtained have been used for the qualitative and quantitative of the results which reflect the efficacy of the applied methodology. Conclusion: The didactic model of the parameters researched in the framework of a specific study of pedagogic diagnostics is based on a general, interdisciplinary approach. Enhanced durability of the acquired knowledge proves the transition of that knowledge from short-term memory storage into long-term memory of pupils and students, which justifies the conclusion that didactic plays have beneficial effects for the betterment of learners’ cognitive skills. The innovations in teaching enhance the motivation, creativity and independent cognitive activity in the process of acquiring the material thought. The innovative methods allow for untraditional means for assessing the level of knowledge acquisition. This makes possible the timely discovery of knowledge gaps and the introduction of compensatory techniques, which in turn leads to deeper and more durable acquisition of knowledge.

Keywords: objectivity, reliability and validity of pedagogical diagnostic parameters introduced in the framework of a specific research

Procedia PDF Downloads 393

Authors: Bahman Gorjian

Abstract:

This study investigated the effects of closed-captioning on vocabulary learning and listening comprehension of English-language movies. Captioning is thus an effective language-learning tool for persons learning English as a second language. Because students may learn a foreign language "passively," utilizing subtitles on television could make learning English enjoyable for them. Closed captioning is an electrical technique that converts spoken words from a television program's audio into written text that mimics subtitles in another language. The findings of this study showed the importance of using closed-captioning software when learning a foreign language. As a result, these must be considered when teaching EFL/ESL. The influence of watching movies with closed captions on vocabulary and hearing is compared in this study. This goal can be reached by employing a closed-captioned movie as a teaching tool in the classroom. This research was critical because it demonstrates the advantages of closed-captioning programs in EFL classrooms for both teachers and students. The study's findings assisted teachers in better understanding how to employ closed captioning as a teaching tool in the classroom. The effects will be seen as even more significant for language learners who use the method.

Keywords: closed-captions, listening, comprehension, vcabulary

Procedia PDF Downloads 89

Authors: Ahmed Ashit

Abstract:

Image fusion is a significant and efficient image processing method used for detecting different types of tumors. This method has been used as an effective combination technique for obtaining high quality images that combine anatomy and physiology of an organ. It is the main key in the huge biomedical machines for diagnosing cancer such as PET-CT machine. This thesis aims to develop an image analysis system for the detection of the eye tumor. Different image processing methods are used to extract the tumor and then mark it on the original image. The images are first smoothed using median filtering. The background of the image is subtracted, to be then added to the original, results in a brighter area of interest or tumor area. The images are adjusted in order to increase the intensity of their pixels which lead to clearer and brighter images. once the images are enhanced, the edges of the images are detected using canny operators results in a segmented image comprises only of the pupil and the tumor for the abnormal images, and the pupil only for the normal images that have no tumor. The images of normal and abnormal images are collected from two sources: “Miles Research” and “Eye Cancer”. The computerized experimental results show that the developed image fusion based eye tumor detection system is capable of detecting the eye tumor and segment it to be superimposed on the original image.

Keywords: image fusion, eye tumor, canny operators, superimposed

Procedia PDF Downloads 363

Authors: Amr Abdel Azim Ali, G. A. Elsheikh, Moutaz Hegazy

Abstract:

This paper presents verification of a modeling and simulation for a Spacecraft (SC) attitude and orbit control system. Detailed formulation of coupled SC orbital and attitude equations of motion is performed in order to achieve accepted accuracy to meet the requirements of multitargets tracking and orbit correction complex modes. Correction of the target parameter based on the estimated state vector during shooting time to enhance pointing accuracy is considered. Time-optimal nonlinear feedback control technique was used in order to take full advantage of the maximum torques that the controller can deliver. This simulation provides options for visualizing SC trajectory and attitude in a 3D environment by including an interface with V-Realm Builder and VR Sink in Simulink/MATLAB. Verification data confirms the simulation results, ensuring that the model and the proposed control law can be used successfully for large and fast tracking and is robust enough to keep the pointing accuracy within the desired limits with considerable uncertainty in inertia and control torque.

Keywords: attitude and orbit control, time-optimal nonlinear feedback control, modeling and simulation, pointing accuracy, maximum torques

Procedia PDF Downloads 332

Authors: Shelley Jones

Abstract:

Assumptions abound that education for girls will, as a matter of course, lead to their economic empowerment as women; yet. little is known about the ways in which schooling for girls, who traditionally/historically would not have had opportunities for post-primary, or perhaps even primary education – such as the participants in this study based in rural Uganda - in reality, impacts their economic situations. There is a need forlongitudinal studies in which women share experiences, understandings, and reflections of their lives that can inform our knowledge of this. In response, this paper reports on stage four of a longitudinal case study (2004-2018) focused on education and empowerment for girls and women in rural Uganda, in which 13 of the 15 participants from the original study participated. This paper understands empowerment as not simply increased opportunities (e.g., employment) but also real gains in power, freedoms that enable agentive action, and authentic and viable choices/alternatives that offer ‘exit options’ from unsatisfactory situations. As with the other stages, this study used a critical, postmodernist, global feminist ethnographic methodology, multimodal and qualitative data collection. Participants participated in interviews, focus group discussions, and a two-day workshop, which explored their understandings of how/if they understood post-primary education to have contributed to their economic empowerment. A constructivist grounded theory approach was used for data analysis to capture major themes. Findings indicate that although all participants believe that post-primary education provided them with economic opportunities they would not have had otherwise, the parameters of their economic empowerment were severely constrained by historic and extant sociocultural, economic, political, and institutional structures that continue to disempower girls and women, as well as additional financial responsibilities that they assumed to support others. Even though the participants had post-primary education, and they were able to obtain employment or operate their own businesses that they would not likely have been able to do without post-primary education, the majority of the participants’ incomes were not sufficient to elevate them financially above the extreme poverty level, especially as many were single mothers and the sole income earners in their households. Furthermore, most deemed their working conditions unsatisfactory and their positions precarious; they also experienced sexual harassment and abuse in the labour force. Additionally, employment for the participants resulted in a double work burden: long days at work, surrounded by many hours of domestic work at home (which, even if they had spousal partners, still fell almost exclusively to women). In conclusion, although the participants seem to have experienced some increase in economic empowerment, largely due to skills, knowledge, and qualifications gained at the post-primary level, numerous barriers prevented them from maximizing their capabilities and making significant gains in empowerment. There is need, in addition to providing education (primary, secondary, and tertiary) to girls, to address systemic gender inequalities that mitigate against women’s empowerment, as well as opportunities and freedom for women to come together and demand fair pay, reasonable working conditions, and benefits, freedom from gender-based harassment and assault in the workplace, as well as advocate for equal distribution of domestic work as a cultural change.

Keywords: girls' post-primary education, women's empowerment, uganda, employment

Procedia PDF Downloads 146

Authors: Guohua Tu, Zhi Fu, Zhiwei Hu, Neil D Sandham, Jianqiang Chen

Abstract:

Tripping of boundary-layers from laminar to turbulent flow, which may be necessary in specific practical applications, requires high amplitude disturbances to be introduced into the boundary layers without large drag penalties. As a possible improvement on fixed trip devices, a technique based on vortex shedding for enhancing supersonic flow transition is demonstrated in the present paper for a Mach 1.5 boundary layer. The compressible Navier-Stokes equations are solved directly using a high-order (fifth-order in space and third-order in time) finite difference method for small-scale cylinders suspended transversely near the wall. For cylinders with proper diameter and mount location, asymmetry vortices shed within the boundary layer are capable of tripping laminar-turbulent transition. Full three-dimensional simulations showed that transition was enhanced. A parametric study of the size and mounting location of the cylinder is carried out to identify the most effective setup. It is also found that the vortex shedding can be suppressed by some factors such as wall effect.

Keywords: boundary layer instability, boundary layer transition, vortex shedding, supersonic flows, flow control

Procedia PDF Downloads 365

Authors: Saba Rahman, Arvind K. Jain, S. D. Bharti, T. K. Datta

Abstract:

Chimneys are generally tall and slender structures with circular cross-sections, due to which they are highly prone to wind forces. Wind exerts pressure on the wall of the chimneys, which produces unwanted forces. Vortex-induced oscillation is one of such excitations which can lead to the failure of the chimneys. Therefore, vortex-induced oscillation of chimneys is of great concern to researchers and practitioners since many failures of chimneys due to vortex shedding have occurred in the past. As a consequence, extensive research has taken place on the subject over decades. Many laboratory experiments have been performed to verify the theoretical models proposed to predict vortex-induced forces, including aero-elastic effects. Comparatively, very few proto-type measurement data have been recorded to verify the proposed theoretical models. Because of this reason, the theoretical models developed with the help of experimental laboratory data are utilized for analyzing the chimneys for vortex-induced forces. This calls for reliability analysis of the predictions of the responses of the chimneys produced due to vortex shedding phenomena. Although several works of literature exist on the vortex-induced oscillation of chimneys, including code provisions, the reliability analysis of chimneys against failure caused due to vortex shedding is scanty. In the present study, the reliability analysis of chimneys against vortex shedding failure is presented, assuming the uncertainty in vortex shedding phenomena to be significantly more than other uncertainties, and hence, the latter is ignored. The vortex shedding is modeled as a stationary random process and is represented by a power spectral density function (PSDF). It is assumed that the vortex shedding forces are perfectly correlated and act over the top one-third height of the chimney. The PSDF of the tip displacement of the chimney is obtained by performing a frequency domain spectral analysis using a matrix approach. For this purpose, both chimney and random wind forces are discretized over a number of points along with the height of the chimney. The method of analysis duly accounts for the aero-elastic effects. The double barrier threshold crossing level, as proposed by Vanmarcke, is used for determining the probability of crossing different threshold levels of the tip displacement of the chimney. Assuming the annual distribution of the mean wind velocity to be a Gumbel type-I distribution, the fragility curve denoting the variation of the annual probability of threshold crossing against different threshold levels of the tip displacement of the chimney is determined. The reliability estimate is derived from the fragility curve. A 210m tall concrete chimney with a base diameter of 35m, top diameter as 21m, and thickness as 0.3m has been taken as an illustrative example. The terrain condition is assumed to be that corresponding to the city center. The expression for the PSDF of the vortex shedding force is taken to be used by Vickery and Basu. The results of the study show that the threshold crossing reliability of the tip displacement of the chimney is significantly influenced by the assumed structural damping and the Gumbel distribution parameters. Further, the aero-elastic effect influences the reliability estimate to a great extent for small structural damping.

Keywords: chimney, fragility curve, reliability analysis, vortex-induced vibration

Procedia PDF Downloads 160

Authors: Jillian Gardner, Hilde D. Miniggio

Abstract:

The increasing prevalence of obesity has driven the pursuit of alternative weight loss strategies, such as jaw wiring (or ‘slimming wires’), a technique known in the medical community as maxillomandibular fixation, which has evolved beyond its original intention of treating temporomandibular joint disorders. Individuals have increasingly sought and utilized the procedure for weight loss purposes. Although legal in South Africa, this trend presents dentists with ethical dilemmas, as they face requests for interventions that prioritize aesthetic preferences over medical necessity. Drawing on scholarly literature and the four principles framework of Beauchamp and Childress, this ethical analysis offers guidance for dentists facing the ethical dilemma of patient requests for jaw wiring as a weight management intervention. The ethical analysis concludes that dentists who refuse autonomous requests to perform jaw wiring for purely weight loss purposes are ethically justified within the principlist framework in overriding these requests when the principles of non-maleficence and beneficence are at stake. The well-being and health of the patient, as well as societal and professional obligations, justify the refusal to perform jaw wiring purely for weight loss.

Keywords: ethics, jaw wiring, maxillomandibular fixation, principlism, weight loss

Procedia PDF Downloads 57

Authors: Muhammad Shafiq Ahmed, Sabastine Ezugwu

Abstract:

Thermophysical properties of Carbon Tetrachloride (CCl₄), a photothermal fluid used frequently in Photothermal Deflection Spectroscopy (PDS), containing different volume fractions of single walled carbon nanotube (SWCNTs) and their effect on the amplitude of PDS signal are investigated. It is found that the presence of highly thermally conducting SWCNTs in CCl₄ enhances the heat transfer from heated sample to the adjoining photothermal fluid, resulting in an increase in the intensity of amplitude of PDS signal. With the increasing volume fraction of SWCNTs in CCl₄, the amplitude of PDS signal is nearly doubled for volume fraction fopt =3.7X10⁻³ %., after that the signal drops with a further increase in the fraction of SWCNTs. It is shown that the use of highly thermally conducting carbon nanotubes enhances the heat exchange coefficient between the heated sample surface and adjoining fluid, resulting to an enhancement of PDS signal and consequently the improvement in the sensitivity of PDS technique.

Keywords: carbon nanotubes, heat transfer, nanofluid, photothermal deflection spectroscopy, thermophysical properties

Procedia PDF Downloads 158

Authors: Yared Yitagesu Tilahun

Abstract:

Every nation, developed or developing, relies on transportation, but Addis Abeba City's transportation service is impacted by a number of variables. The current study's objectives are to determine the factors that influence transportation and gauge consumer satisfaction with such services in Addis Abeba. Customers and employees of Addis Ababa's transportation service authority would be the study's target group. 40 workers of the authority would be counted as part of the 310 000 clients that make up the population of the searcher service. Using a straightforward random selection technique, the researcher only chose 99 customers and 28 staff from this enormous group due to the considerable cost and time involved. Data gathering and analysis options included both quantitative and qualitative approaches. The results of this poll show that young people between the ages of 18 and 25 make up the majority of respondents (51.6%). The majority of employees and customers indicated that they are not satisfied with Addis Ababa's overall transportation system. The Addis Abeba Transportation Authority prioritizes client happiness by providing fair service. The company should have a system in place for managing time, resources, and people effectively. It should also provide employees the opportunity to contribute to client handling policies.

Keywords: customer satisfaction, transportation, services, determinants

Procedia PDF Downloads 77

Authors: Zahra Hatami, Hesham Ali, David Volkman

Abstract:

Selecting a portfolio for investing is a crucial decision for individuals and legal entities. In the last two decades, with economic globalization, a stream of financial innovations has rushed to the aid of financial institutions. The importance of selecting stocks for the portfolio is always a challenging task for investors. This study aims to create a financial network to identify optimal portfolios using network centralities metrics. This research presents a community detection technique of superior stocks that can be described as an optimal stock portfolio to be used by investors. By using the advantages of a network and its property in extracted communities, a group of stocks was selected for each of the various time periods. The performance of the optimal portfolios compared to the famous index. Their Sharpe ratio was calculated in a timely manner to evaluate their profit for making decisions. The analysis shows that the selected potential portfolio from stocks with low centrality measurement can outperform the market; however, they have a lower Sharpe ratio than stocks with high centrality scores. In other words, stocks with low centralities could outperform the S&P500 yet have a lower Sharpe ratio than high central stocks.

Keywords: portfolio management performance, network analysis, centrality measurements, Sharpe ratio

Procedia PDF Downloads 154

Authors: Semeh Ben Salem, Sami Naouali, Moetez Sallami

Abstract:

Clustering is a well known data mining technique used in pattern recognition and information retrieval. The initial dataset to be clustered can either contain categorical or numeric data. Each type of data has its own specific clustering algorithm. In this context, two algorithms are proposed: the k-means for clustering numeric datasets and the k-modes for categorical datasets. The main encountered problem in data mining applications is clustering categorical dataset so relevant in the datasets. One main issue to achieve the clustering process on categorical values is to transform the categorical attributes into numeric measures and directly apply the k-means algorithm instead the k-modes. In this paper, it is proposed to experiment an approach based on the previous issue by transforming the categorical values into numeric ones using the relative frequency of each modality in the attributes. The proposed approach is compared with a previously method based on transforming the categorical datasets into binary values. The scalability and accuracy of the two methods are experimented. The obtained results show that our proposed method outperforms the binary method in all cases.

Keywords: clustering, unsupervised learning, pattern recognition, categorical datasets, knowledge discovery, k-means

Procedia PDF Downloads 259

Authors: Mohanad Alhabo, Naveed Nawaz

Abstract:

The ongoing call or data session must be maintained to ensure a good quality of service. This can be accomplished by performing the handover procedure while the user is on the move. However, the dense deployment of small cells in 5G networks is a challenging issue due to the extensive number of handovers. In this paper, a neighbour cell list method is proposed to reduce the number of target small cells and hence minimizing the number of handovers. The neighbour cell list is built by omitting cells that could cause an unnecessary handover and handover failure because of short time of stay of the user in these cells. A multi-attribute decision making technique, simple additive weighting, is then applied to the optimized neighbour cell list. Multi-tier small cells network is considered in this work. The performance of the proposed method is analysed and compared with that of the existing methods. Results disclose that our method has decreased the candidate small cell list, unnecessary handovers, handover failure, and short time of stay cells compared to the competitive method.

Keywords: handover, HetNets, multi-attribute decision making, small cells

Procedia PDF Downloads 120

Authors: Mustafa Dogru, Ruveyda Komurlu

Abstract:

Companies and professionals in the construction sector face various risks in every project depending on the characteristics, size, complexity, the location of the projects and the techniques used. Some risks’ effects may increase as the project progresses whereas new risks may emerge. Because of the ever-changing nature of the risks, risk management is a cyclical process that needs to be repeated throughout the project. Since the risks threaten the success of the project, risk management is an important part of the entire project management process. The aims of this study are to emphasize the importance of risk management in construction projects, summarize the risk identification process, and introduce a number of methods for preventing risks such as alternative design, checklists, prototyping and test-analysis-correction technique etc. Following the literature review conducted to list the techniques for preventing risks, case studies has been performed to compare and evaluate the success of the techniques in a number of completed projects with the same typology, performed domestic and international. Findings of the study suggest that controlling and minimizing the level of the risks in construction projects, taking optimal precautions for different risks, and mitigating or eliminating the effects of risks are important in order to prevent additional costs for the project. Additionally, focusing on the risks that have highest impact is the most rational way to minimize the effects of the risks on projects.

Keywords: construction projects, construction management, project management, risk management

Procedia PDF Downloads 319

Authors: R. Rama Kishore, Sunesh

Abstract:

This paper presents an optimized, robust, and secured watermarking technique. The methodology used in this work is the combination of entropy and chaotic grid map. The proposed methodology incorporates Discrete Cosine Transform (DCT) on the host image. To improve the imperceptibility of the method, the host image DCT blocks, where the watermark is to be embedded, are further optimized by considering the entropy of the blocks. Chaotic grid is used as a key to reorder the DCT blocks so that it will further increase security while selecting the watermark embedding locations and its sequence. Without a key, one cannot reveal the exact watermark from the watermarked image. The proposed method is implemented on four different images. It is concluded that the proposed method is giving better results in terms of imperceptibility measured through PSNR and found to be above 50. In order to prove the effectiveness of the method, the performance analysis is done after implementing different attacks on the watermarked images. It is found that the methodology is very strong against JPEG compression attack even with the quality parameter up to 15. The experimental results are confirming that the combination of entropy and chaotic grid map method is strong and secured to different image processing attacks.

Keywords: digital watermarking, discreate cosine transform, chaotic grid map, entropy

Procedia PDF Downloads 253

Authors: Amal Alatar

Abstract:

The architectural legacy is considered a significant factor, which left its features on the shape of buildings and historical and archaeological sites all over the world. In this framework, this paper focuses on Umm Qais town, located in Northern Jordan, which includes archaeological remains of the ancient Decapolis city of Gadara, still the witness of the originality and architectural identity of the city. 3D modeling is a public asset and a valuable resource for cultural heritage. This technique allows the possibility to make accurate representations of objects, structures, and surfaces. Hence, these representations increase valuable assets when thinking about cultural heritage. The Heritage Building Information Modeling (HBIM) is considered an effective tool to represent information on Cultural Heritage (CH) which can be used for documentation, restoration, conservation, presentation, and research purposes. Therefore, this paper focus on the interdisciplinary project of the virtualization of the West Theater in Gadara (Umm Qais) for 3D documentation and structural studies. The derived 3D model of the cultural heritage is the basis for further archaeological studies; the challenges of the work stay in the acquisition, processing, and integration of the multi-resolution data as well as their interactive visualization.

Keywords: archaeology, 3D modeling, Umm Qais, culture heritage, Jordan

Procedia PDF Downloads 101

Authors: Mina Rahmani Pour

Abstract:

Negative consequences of unemployment are: increasing age at marriage, addiction, depression, drug trafficking, divorce, immigration, elite, frustration, delinquency, theft, murder, etc., has led to addressing the issue of employment by economic planners, public authorities, chief executive economic conditions in different countries and different time is important. All countries are faced with the problem of unemployment. By identifying the influential factors of occupational employment and employing strengths in the basic steps can be taken to reduce unemployment. In this study, the most significant factors affecting employment has identified 12 variables based on interviews conducted Choose Vtasyrafzaysh engaged in three main business is discussed. DRGAM next question the 8 expert ministry to respond to it is distributed and for weight Horns AZFN Shannon entropy and the ranking criteria of the (SAW, TOPSIS) used. According to the results of the above methods are not compatible with each other, to reach a general consensus on the rating criteria of the technique of integrating (POSET) involving average, Borda, copeland is used. Ultimately, there is no difference between the employments in the economic sector jobs of increased employment.

Keywords: employment, effective techniques, SAW, TOPSIS

Procedia PDF Downloads 235

Authors: Chai Mingming, Li Lei, Lu Xiaoxia

Abstract:

In this paper, the mechanism of stratified liquids’ mixing in a cylinder is investigated. It is focused on the effects of Rayleigh-Taylor Instability (RTI) and rotation of the cylinder on liquid interface mixing. For miscible liquids, Planar Laser Induced Fluorescence (PLIF) technique is applied to record the concentration field for one liquid. Intensity of Segregation (IOS) is used to describe the mixing status. For immiscible liquids, High Speed Camera is adopted to record the development of the interface. The experiment of RTI indicates that it plays a great role in the mixing process, and meanwhile the large-scale mixing is triggered, and subsequently the span of the stripes decreases, showing that the mesoscale mixing is coming into being. The rotation experiments show that the spin-down process has a great role in liquid mixing, during which the upper liquid falls down rapidly along the wall and crashes into the lower liquid. During this process, a lot of interface instabilities are excited. Liquids mix rapidly in the spin-down process. It can be concluded that no matter what ways have been adopted to speed up liquid mixing, the fundamental reason is the interface instabilities which increase the area of the interface between liquids and increase the relative velocity of the two liquids.

Keywords: interface instability, liquid mixing, Rayleigh-Taylor Instability, spin-down process, spin-up process

Procedia PDF Downloads 301