Search results for: stability enhancement

Authors: Dana J. Abed, Mu'tasim S. Abdel-Jaber, Nasim K. Shatarat

Abstract:

In this paper, an experimental study on twelve square columns was conducted to investigate the influence of cross-sectional size on axial compressive capacity of carbon fiber reinforced polymers (CFRP) wrapped square reinforced concrete (RC) short columns subjected to eccentric loadings. The columns were divided into three groups with three cross sections (200×200×1200, 250×250×1500 and 300×300×1800 mm). Each group was tested under two different eccentricities: 10% and 20% of the width of samples measured from the center of the column cross section. Four columns were developed in each arrangement. Two columns in each category were left unwrapped as control samples, and two were wrapped with one layer CFRP perpendicular to the specimen surface. In general; CFRP sheets has enhanced the performance of the strengthened columns compared to the control columns. It was noticed that the percentage of compressive capacity enhancement was decreased by increasing the cross-sectional size, and increasing loading eccentricity generally leads to reduced load bearing capacity in columns. In the same group specimens, when the eccentricity increased the percentage of enhancement in load carrying capacity was increased. The study concludes that the optimum use of the CFRP sheets for axial strength enhancement is for smaller cross-section columns under higher eccentricities.

Keywords: CFRP, columns, eccentric loading, cross-sectional

Procedia PDF Downloads 177

Authors: B. Mahfoud, A. Bendjagloli

Abstract:

The effect of an axial magnetic field on the flow produced by co-rotation of the top and bottom disks in a vertical cylindrical heated from below is numerically analyzed. The governing Navier-Stokes, energy, and potential equations are solved by using the finite-volume method. It was observed that the Reynolds number is increased, the axisymmetric basic state loses stability to circular patterns of axisymmetric vortices and spiral waves. In mixed convection case the axisymmetric mode disappears giving an asymmetric mode m=1. It was also found that the primary thresholds Recr corresponding to the modes m=1and 2, increase with increasing of the Hartmann number (Ha). Finally, stability diagrams have been established according to the numerical results of this investigation. These diagrams giving the evolution of the primary thresholds as a function of the Hartmann number for various values of the Richardson number.

Keywords: bifurcation, co-rotating end disks, magnetic field, stability diagrams, vortices

Procedia PDF Downloads 351

Authors: F. Adjel, S. Almi, D. Barkat

Abstract:

The synergistic solvent extraction of cobalt (II) from 0.33 mol dm-3 Na2SO4 aqueous solutions with capric acid (HL) in the absence and presence of tri-n-octylphosphine oxide (TOPO) in chloroform at 25°C, has been studied. The extracted species when the capric acid compound was used alone, is CoL2(HL)2. In the presence of TOPO, a remarkable enhancement on the extraction of nickel (II) with 0.02 mol dm-3 capric acid was observed upon the addition of 0.0025 to 0.01 mol dm-3 TOPO in chloroform. From an synergistic extraction- equilibrium study, the synergistic enhancement was ascribed to the adduct formation CoL2(HL)2 n(TOPO). The TOPO-HL interaction strongly influences the synergistic extraction efficiency. The synergistic extraction stoichiometry of cobalt (II) with capric acid and TOPO is studied with the methods of slope analysis. The equilibrium constants were determined.

Keywords: solvent extraction, cobalt (II), capric acid, TOPO, synergism

Procedia PDF Downloads 528

Authors: Raouf Fareh, Maarouf Saad, Sofiane Khadraoui, Tamer Rabie

Abstract:

This paper presents a tracking control strategy based on Lyapunov approach for nonholonomic wheeled mobile robot. This control strategy consists of two levels. First, a kinematic controller is developed to adjust the right and left wheel velocities. Using this velocity control law, the stability of the tracking error is guaranteed using Lyapunov approach. This kinematic controller cannot be generated directly by the motors. To overcome this problem, the second level of the controllers, dynamic control, is designed. This dynamic control law is developed based on Lyapunov theory in order to track the desired trajectories of the mobile robot. The stability of the tracking error is proved using Lupunov and Barbalat approaches. Simulation results on a nonholonomic wheeled mobile robot are given to demonstrate the feasibility and effectiveness of the presented approach.

Keywords: mobile robot, trajectory tracking, Lyapunov, stability

Procedia PDF Downloads 378

Authors: M. Ntswane, N. Mbuma, M. Labuschagne, A. Mofokeng, M. Rantso

Abstract:

Cowpea is an essential legume for the nutrition and health of millions of people in different regions. The production and productivity of the crop are very limited in South Africa due to a lack of adapted and stable genotypes. The improvement of nutritional quality is made possible by manipulating the genes of diverse cowpea genotypes available around the world. Assessing the adaptability and stability of the cowpea mutant genotypes for yield and nutritional quality requires examining them in different environments. The objective of the study was to determine the adaptability and stability of cowpea mutant genotypes under South African conditions and to identify the superior genotypes that combine grain yield components, antioxidants, and nutritional quality. Thirty-one cowpea genotypes were obtained from the Agricultural Research Council grain crops (ARC-GC) and were planted in Glen, Mafikeng, Polokwane, Potchefstroom, Taung, and Vaalharts during the 2021/22 summer cropping season. Significant genotype by location interactions indicated the possibility of genetic improvement of these traits. The genotype plus genotype by environment indicated broad adaptability and stability of mutant genotypes. The principal component analysis identified the association of the genotypes with the traits. Phenotypic correlation analysis showed that Zn and protein content were significant and positively correlated and suggested the possibility of indirect selection of these traits. Results from this study could be used to help plant breeders in making informed decisions and developing nutritionally improved cowpea genotypes with the aim of addressing the challenges of poor nutritional quality.

Keywords: cowpea seeds, adaptability, stability, mineral elements, protein content

Procedia PDF Downloads 119

Authors: Kooshan Nayebzadeh, Maryam Enteshari

Abstract:

In this study, the oxidative stability of soybean oil under different storage temperatures (4 and 25 ˚C) and during 6-month shelf-life was investigated by various analytical methods and headspace-liquid phase microextraction (HS-LPME) coupled to gas chromatography-mass spectrometry (GC-MS). Oxidation changes were monitored by analytical parameters consisted of acid value (AV), peroxide value (PV), p-Anisidine value (p-AV), thiobarbituric acid value (TBA), fatty acids profile, iodine value (IV) and oxidative stability index (OSI). In addition, concentrations of hexanal and heptanal as secondary volatile oxidation compounds were determined by HS-LPME/GC-MS technique. Rate of oxidation in soybean oil which stored at 25 ˚C was so higher. The AV, p-AV, and TBA were gradually increased during 6 months, while the amount of unsaturated fatty acids, IV, and OSI decreased. Other parameters included concentrations of both hexanal and heptanal, and PV exhibited increasing trend during primitive months of storage; then, at the end of third and fourth months a sudden decrement was understood for the concentrations of hexanal and heptanal and the amount of PV, simultaneously. The latter parameters increased again until the end of shelf-time. As a result, the temperature and time were effective factors in oxidative stability of soybean oil. Also intensive correlations were found for soybean oil at 4 ˚C between AV and TBA (r2=0.96), PV and p-AV (r2=0.9), IV and TBA (-r2=0.9), and for soybean oil stored at 4 ˚C between p-AV and TBA (r2=0.99).

Keywords: headspace-liquid phase microextraction, oxidation, shelf-life, soybean oil

Procedia PDF Downloads 400

Authors: Shishir Lamichhane, Saurav Dulal, Bibek Gautam, Madan Thapa Magar, Indraman Tamrakar

Abstract:

Renewable energies such as wind turbines and solar photovoltaic have gained significance as a result of global environmental pollution and energy crises. These sources of energy are converted into electrical energy and delivered to end-users through the utility system. As a result of the widespread use of power electronics-based grid-interfacing technologies to accommodate renewable sources of energy, the prevalence of converters has expanded as well. As a result, the power system's rotating inertia is decreasing, endangering the utility grid's stability. The use of Virtual Synchronous Machine (VSM) technology has been proposed to overcome the grid stability problem due to low rotating inertia. The grid-connected inverter used in VSM can be controlled to emulate inertia, which replicates the external features of a synchronous generator. As a result, the rotating inertia is increased to support the power system's stability. A power angle control strategy is proposed in this paper and its model is simulated in MATLAB/Simulink to study the effects of parameter disturbances on the active power and frequency for a VSM. The system consists of a synchronous generator, which is modeled in such a way that the frequency drops to an unacceptable region during transient conditions due to a lack of inertia when VSM is not used. Then, the suggested model incorporating VSM emulates rotating inertia, injecting a controllable amount of energy into the grid during frequency transients to enhance transient stability.

Keywords: damping constant, inertia–constant, ROCOF, transient stability, distributed sources

Procedia PDF Downloads 210

Authors: N. Prabavathy, R. Balasundaraprabhu, S. Shalini, Dhayalan Velauthapillai, S. Prasanna, N. Muthukumarasamy

Abstract:

Dye sensitized solar cell (DSSC) has become a significant research area due to their fundamental and scientific importance in the area of energy conversion. Synthetic dyes as sensitizer in DSSC are efficient and durable but they are costlier, toxic and have the tendency to degrade. Natural sensitizers contain plant pigments such as anthocyanin, carotenoid, flavonoid, and chlorophyll which promote light absorption as well as injection of charges to the conduction band of TiO2 through the sensitizer. But, the efficiency of natural dyes is not up to the mark mainly due to instability of the pigment such as anthocyanin. The stability issues in vitro are mainly due to the effect of solvents on extraction of anthocyanins and their respective pH. Taking this factor into consideration, in the present work, the anthocyanins were extracted from the flower Caesalpinia pulcherrima (C. pulcherrimma) with various solvents and their respective stability and pH values are discussed. The usage of citric acid as solvent to extract anthocyanin has shown good stability than other solvents. It also helps in enhancing the sensitization properties of anthocyanins with Titanium dioxide (TiO2) nanorods. The IPCE spectra show higher photovoltaic performance for dye sensitized TiO2nanorods using citric acid as solvent. The natural DSSC using citric acid as solvent shows a higher efficiency compared to other solvents. Hence citric acid performs to be a safe solvent for natural DSSC in boosting the photovoltaic performance and maintaining the stability of anthocyanins.

Keywords: Caesalpinia pulcherrima, citric acid, dye sensitized solar cells, TiO₂ nanorods

Procedia PDF Downloads 296

Authors: Marija Vitanovа, Igor Gjorgjiev, Viktor Hristovski, Vlado Micov

Abstract:

Evaluation of stability is very important in the process of definition of optimal structural measures for maintenance of bridge structures and their strengthening. To define optimal measures for their repair and strengthening, it is necessary to evaluate their static and seismic stability. Presented in this paper are methodologies for evaluation of the seismic stability of existing reinforced concrete bridges designed without consideration of seismic effects and checking of structural justification of newly designed bridge structures. All bridges are located in the territory of the Republic of North Macedonia. A total of 26 existing bridges of different structural systems have been analyzed. Visual inspection has been carried out for all bridges, along with the definition of three main damage categories according to which structures have been categorized in respect to the need for their repair and strengthening. Investigations involving testing the quality of the built-in materials have been carried out, and dynamic tests pointing to the dynamic characteristics of the structures have been conducted by use of non-destructive methods of ambient vibration measurements. The conclusions drawn from the performed measurements and tests have been used for the development of accurate mathematical models that have been analyzed for static and dynamic loads. Based on the geometrical characteristics of the cross-sections and the physical characteristics of the built-in materials, interaction diagrams have been constructed. These diagrams along with the obtained section quantities under seismic effects, have been used to obtain the bearing capacity of the cross-sections. The results obtained from the conducted analyses point to the need for the repair of certain structural parts of the bridge structures. They indicate that the stability of the superstructure elements is not critical during a seismic effect, unlike the elements of the sub-structure, whose strengthening is necessary.

Keywords: existing bridges, newly designed bridges, reinforced concrete bridges, stability assessment

Procedia PDF Downloads 104

Authors: Siddharth Deshpande, Nihar Masurkar, Vallerinteavide Mavelli Girish, Malan Desai, Chester Drum

Abstract:

Folding and stabilization of recombinant proteins remain a consistent challenge for industrial and therapeutic applications. Proteins derived from thermophilic bacteria often have superior expression and stability qualities. To develop a generalizable approach to protein folding and stabilization, we tested the hypothesis that wrapping a thermostable exoshell around a protein substrate would aid folding and impart thermostable qualities to the internalized substrate. To test the effect of internalizing a protein within a thermostable exoshell (tES), we tested in vitro folding and stability using green fluorescent protein (GFPuv), horseradish peroxidase (HRP) and renilla luciferase (rLuc). The 8nm interior volume of a thermostable ferritin assembly was engineered to accommodate foreign proteins and either present a positive, neutral or negative interior charge environment. We further engineered the tES complex to reversibly assemble and disassemble with pH titration. Template proteins were expressed as inclusion bodies and an in vitro folding protocol was developed that forced proteins to fold inside a single tES. Functional yield was improved 100-fold, 100-fold and 150-fold with use of tES for GFPuv, HRP and rLuc respectively and was highly dependent on the internal charge environment of the tES. After folding, functional proteins could be released from the tES folding cavity using size exclusion chromatography at pH 5.8. Internalized proteins were tested for improved stability against thermal, organic, urea and guanidine denaturation. Our results demonstrated that thermostable exoshells can efficiently refold and stabilize inactive aggregates into functional proteins.

Keywords: thermostable shell, in vitro folding, stability, functional yield

Procedia PDF Downloads 253

Authors: F. Adjel, C. Bensmail, S. Almi, D. Barkat

Abstract:

The synergistic solvent extraction of cobalt (II) from 0.33 mol dm^-3 Na2SO4 aqueous solutions with capric acid (HL) in the absence and presence of methyl isobutyl cétone (MIBK) in chloroform at 25°C, has been studied. The extracted species when the capric acid compound was used alone, is CoL2(HL)2. In the presence of MIBK, a remarkable enhancement on the extraction of nickel (II) with 0.02 mol dm^-3 capric acid was observed upon the addition of 0.0025 to 0.01 mol dm^-3 MIBK in chloroform. From a synergistic extraction-equilibrium study, the synergistic enhancement was ascribed to the adduct formation CoL2(HL)2 n(MIBK). The MIBK-HL interaction strongly influences the synergistic extraction efficiency. The synergistic extraction stoichiometry of cobalt (II) with capric acid and MIBK is studied with the methods of slope analysis. The equilibrium constants were determined.

Keywords: solvent extraction, cobalt (II), capric acid, MIBK, synergism

Procedia PDF Downloads 498

Authors: Markus Mazzola, Gunther Schaaf

Abstract:

A vehicle driving with an Adaptive Cruise Control System (ACC) is usually controlled decentrally, based on the information of radar systems and in some publications based on C2X-Communication (CACC) to guarantee stable platoons. In this paper, we present a Model Predictive Control (MPC) design of a centralized, server-based ACC-System, whereby the vehicular platoon is modeled and controlled as a whole. It is then proven that the proposed MPC design guarantees asymptotic stability and hence string stability of the platoon. The Networked MPC design is chosen to be able to integrate system constraints optimally as well as to reduce the effects of communication delay and packet loss. The performance of the proposed controller is then simulated and analyzed in an LTE communication scenario using the LTE/EPC Network Simulator LENA, which is based on the ns-3 network simulator.

Keywords: adaptive cruise control, centralized server, networked model predictive control, string stability

Procedia PDF Downloads 519

Authors: Belgheis Ebrahimi, Jun Lu

Abstract:

In recent years, there has been a growing recognition of the potential of marine-based functional foods and combination therapies in promoting a healthy lifestyle and exploring their effectiveness in preventing or treating diseases. The combination of marine bioactive compounds or extracts offers synergistic or enhancement effects through various mechanisms, including multi-target actions, improved bioavailability, enhanced bioactivity, and mitigation of potential adverse effects. Both the green-lipped mussel (GLM) and fucoidan derived from brown seaweed are rich in bioactivities. These two, mussel and fucoidan, have not been previously formulated together. This study aims to combine GLM oil from Perna canaliculus with low molecular weight fucoidan (LMWF) extracted from Undaria pinnatifida to investigate the unique mixture’s anti-inflammatory and antioxidant properties. The cytotoxicity of individual compounds and combinations was assessed using the MTT assay in (THP-1 and RAW264.7) cell lines. The anti-inflammatory activity of mussel-fucoidan was evaluated by treating LPS-stimulated human monocyte and macrophage (THP1-1) cells. Subsequently, the inflammatory cytokines released into the supernatant of these cell lines were quantified via ELISA. Antioxidant activity was determined by using the free radical scavenging assay (DPPH). DPPH assay demonstrated that the radical scavenging activity of the combinations, particularly at concentrations exceeding 1 mg/ml, showed a significantly higher percentage of inhibition when compared to the individual component. This suggests an enhancement effect when the two compounds are combined, leading to increased antioxidant activity. In terms of immunomodulatory activity, the individual compounds exhibited distinct behaviors. GLM oil displayed a higher ability to suppress the cytokine TNF- compared to LMWF. Interestingly, the LMWF fraction, when used individually, did not demonstrate TNF- suppression. However, when combined with GLM, the TNF- suppression (anti-inflammatory) activity of the combination was better than GLM or LWMF alone. This observation underscores the potential for enhancement interactions between the two components in terms of anti-inflammatory properties. This study revealed that each individual compound, LMWF, and GLM, possesses unique and notable bioactivity. The combination of these two individual compounds results in an enhancement effect, where the bioactivity of each is enhanced, creating a superior combination. This suggests that the combination of LMWF and GLM has the potential to offer a more potent and multifaceted therapeutic effect, particularly in the context of antioxidant and anti-inflammatory activities. These findings hold promise for the development of novel therapeutic interventions or supplements that harness the enhancement effects.

Keywords: combination, enhancement effect, perna canaliculus, undaria pinnatifida

Procedia PDF Downloads 85

Authors: Djendi Mohmaed

Abstract:

In this paper, we propose a dual adaptive algorithm, which is based on the combination between the forward blind source separation (FBSS) structure and the affine projection algorithm (APA). This proposed algorithm combines the advantages of the source separation properties of the FBSS structure and the fast convergence characteristics of the APA algorithm. The proposed algorithm needs two noisy observations to provide an enhanced speech signal. This process is done in a blind manner without the need for ant priori information about the source signals. The proposed dual forward blind source separation affine projection algorithm is denoted (DFAPA) and used for the first time in an airplane cockpit context to enhance the communication from- and to- the airplane. Intensive experiments were carried out in this sense to evaluate the performance of the proposed DFAPA algorithm.

Keywords: adaptive algorithm, speech enhancement, system mismatch, SNR

Procedia PDF Downloads 139

Authors: Debamitra Chakravorty, Pratap K. Parida

Abstract:

Cold-adapted proteases enhance wash performance in low-temperature laundry resulting in a reduction in energy consumption and wear of textiles and are also used in the dehairing process in leather industries. Unfortunately, the possible drawbacks of using cold-adapted proteases are their instability at higher temperatures. Therefore, proteases with broad temperature stability are required. Unfortunately, wild-type cold-adapted proteases exhibit instability at higher temperatures and thus have low shelf lives. Therefore, attempts to engineer cold-adapted proteases by protein engineering were made previously by directed evolution and random mutagenesis. The lacuna is the time, capital, and labour involved to obtain these variants are very demanding and challenging. Therefore, rational engineering for cold stability without compromising an enzyme's optimum pH and temperature for activity is the current requirement. In this work, mutations were rationally designed with the aid of high throughput computational methodology of network analysis, evolutionary conservation scores, and molecular dynamics simulations for Savinase from Bacillus lentus with the intention of rendering the mutants cold stable without affecting their temperature and pH optimum for activity. Further, an attempt was made to incorporate a mutation in the most stable mutant rationally obtained by this method to introduce oxidative stability in the mutant. Such enzymes are desired in detergents with bleaching agents. In silico analysis by performing 300 ns molecular dynamics simulations at 5 different temperatures revealed that these three mutants were found to be better in cold stability compared to the wild type Savinase from Bacillus lentus. Conclusively, this work shows that cold adaptation without losing optimum temperature and pH stability and additionally stability from oxidative damage can be rationally designed by in silico enzyme engineering. The key findings of this work were first, the in silico data of H5 (cold stable savinase) used as a control in this work, corroborated with its reported wet lab temperature stability data. Secondly, three cold stable mutants of Savinase from Bacillus lentus were rationally identified. Lastly, a mutation which will stabilize savinase against oxidative damage was additionally identified.

Keywords: cold stability, molecular dynamics simulations, protein engineering, rational design

Procedia PDF Downloads 145

Authors: K. Paradkar, S. N. Mudliar, A. Sharma, A. B. Pandit, R. A. Pandey

Abstract:

The study explores the hybrid combination of Hydrodynamic Cavitation (HC) and Subcritical Wet Air Oxidation-based pretreatment of complex industrial effluent to enhance the biodegradability selectively (without major COD destruction) to facilitate subsequent enhanced downstream processing via anaerobic or aerobic biological treatment. Advanced oxidation based techniques can be less efficient as standalone options and a hybrid approach by combining Hydrodynamic Cavitation (HC), and Wet Air Oxidation (WAO) can lead to a synergistic effect since both the options are based on common free radical mechanism. The HC can be used for initial turbulence and generation of hotspots which can begin the free radical attack and this agitating mixture then can be subjected to less intense WAO since initial heat (to raise the activation energy) can be taken care by HC alone. Lab-scale venturi-based hydrodynamic cavitation and wet air oxidation reactor with biomethanated distillery wastewater (BMDWW) as a model effluent was examined for establishing the proof-of-concept. The results indicated that for a desirable biodegradability index (BOD: COD - BI) enhancement (up to 0.4), the Cavitation (standalone) pretreatment condition was: 5 bar and 88 min reaction time with a COD reduction of 36 % and BI enhancement of up to 0.27 (initial BI - 0.17). The optimum WAO condition (standalone) was: 150oC, 6 bar and 30 minutes with 31% COD reduction and 0.33 BI. The hybrid pretreatment (combined Cavitation + WAO) worked out to be 23.18 min HC (at 5 bar) followed by 30 min WAO at 150oC, 6 bar, at which around 50% COD was retained yielding a BI of 0.55. FTIR & NMR analysis of pretreated effluent indicated dissociation and/or reorientation of complex organic compounds in untreated effluent to simpler organic compounds post-pretreatment.

Keywords: hybrid, hydrodynamic cavitation, wet air oxidation, biodegradability index

Procedia PDF Downloads 621

Authors: A. S. Gorobtsov, A. S. Polyanina, A. E. Andreev

Abstract:

The movement of points feet of the anthropomorphous robot in space occurs along some stable trajectory of a known form. A large number of modifications to the methods of control of biped robots indicate the fundamental complexity of the problem of stability of the program trajectory and, consequently, the stability of the control for the deviation for this trajectory. Existing gait generators use piecewise interpolation of program trajectories. This leads to jumps in the acceleration at the boundaries of sites. Another interpolation can be realized using differential equations with fractional derivatives. In work, the approach to synthesis of generators of program trajectories is considered. The resulting system of nonlinear differential equations describes a smooth trajectory of movement having rectilinear sites. The method is based on the theory of an asymptotic stability of invariant sets. The stability of such systems in the area of localization of oscillatory processes is investigated. The boundary of the area is a bounded closed surface. In the corresponding subspaces of the oscillatory circuits, the resulting stable limit cycles are curves having rectilinear sites. The solution of the problem is carried out by means of synthesis of a set of the continuous smooth controls with feedback. The necessary geometry of closed trajectories of movement is obtained due to the introduction of high-order nonlinearities in the control of stabilization systems. The offered method was used for the generation of trajectories of movement of point’s feet of the anthropomorphous robot. The synthesis of the robot's program movement was carried out by means of the inverse method.

Keywords: control, limits cycle, robot, stability

Procedia PDF Downloads 332

Authors: Azam Bayat, Aref Khalkhali, Ali Reza Mahjoub

Abstract:

Healthy and viable herbal supplement were prepared from wheat by a green route. This organic biomaterial was named Nutrition Bio-shield Superfood (NBS). The NBS supplement had various vitamins, macro and micro molecules, and ingredients. In this study, 20 small Balb/C labile specimens were used in a weighing 30 ± 5 range. The samples were randomly divided into different groups, then the groups were divided into 5 groups. According to the results of this study, the mean number of white blood cells and neutrophil percentage in the experimental group receiving healthy and live dietary supplement showed a significant increase at the 5% probability level in all three groups received 50, 100 and 150 mg/ kg body weight of the mouse compared to the control group. In general, the dietary supplement increases the level of immunity.

Keywords: healthy and live herbal supplement, biomaterial, immune system, enhancement

Procedia PDF Downloads 153

Authors: Seyed Abolhasan Naeini, Elham Ghanbari Alamooti

Abstract:

Static stability of soil slopes using numerical simulation by a finite element code, ABAQUS, has been investigated, and safety factors of the slopes achieved in the case of static load of a 10-storey building. The embankments have the same soil condition but different loading distance from the slope heel. The numerical method for estimating safety factors is 'Strength Reduction Method' (SRM). Mohr-Coulomb criterion used in the numerical simulations. Two steps used for measuring the safety factors of the slopes: first is under gravity loading, and the second is under static loading of a building near the slope heel. These safety factors measured from SRM, are compared with the values from Limit Equilibrium Method, LEM. Results show that there is good agreement between SRM and LEM. Also, it is seen that by increasing the distance from slope heel, safety factors increases.

Keywords: limit equilibrium method, static stability, soil slopes, strength reduction method

Procedia PDF Downloads 168

Authors: N. Ghatwary, A. Ahmed, H. Jalab

Abstract:

In this paper, an approach for the liver tumor detection in computed tomography (CT) images is represented. The detection process is based on classifying the features of target liver cell to either tumor or non-tumor. Fractional differential (FD) is applied for enhancement of Liver CT images, with the aim of enhancing texture and edge features. Later on, a fusion method is applied to merge between the various enhanced images and produce a variety of feature improvement, which will increase the accuracy of classification. Each image is divided into NxN non-overlapping blocks, to extract the desired features. Support vector machines (SVM) classifier is trained later on a supplied dataset different from the tested one. Finally, the block cells are identified whether they are classified as tumor or not. Our approach is validated on a group of patients’ CT liver tumor datasets. The experiment results demonstrated the efficiency of detection in the proposed technique.

Keywords: fractional differential (FD), computed tomography (CT), fusion, aplha, texture features.

Procedia PDF Downloads 360

Authors: Osama Brinji, Wing Kong Chiu, Graham Tew

Abstract:

Understanding the stability of rail ballast is one of the most important aspects in the railways. An unstable track may cause some issues such as unnecessary vibration and ultimately loss of track quality. The track foundation plays an important role in the stabilization of the railway. The dynamic response of rail ballast in the vicinity of the rail sleeper can affect the stability of the rail track and this has not been studied in detail. A review of literature showed that most of the works focused on the area under the concrete sleeper. Although there are some theories about the shear (longitudinal) effect of the rail ballast, these have not properly been studied and hence are not well understood. The stability of a rail track will depend on the compactness of the ballast in its vicinity. This paper will try to determine the dynamic response of the ballast to identify its resonant behaviour. This preliminary research is one of several studies that examine the vibration response of the granular materials. The main aim is to use this information for future design of sleepers to ensure that any dynamic response of the sleeper will not compromise the state of compactness of the ballast. This paper will report on the dependence of damping and the natural frequency of the ballast as a function of depth and distance from the point of excitation introduced through a concrete block. The concrete block is used to simulate a sleeper and the ballast is simulated with gravel. In spite of these approximations, the results presented in the paper will show an agreement with theories and the assumptions that are used in study the mechanical behaviour of the rail ballast.

Keywords: ballast, dynamic response, sleeper, stability

Procedia PDF Downloads 503

Authors: Eng. Alaa K. Satti Salih

Abstract:

Revolutions Applications such as telecommunications, hands-free communications, recording, etc. which need at least one microphone, the signal is usually infected by noise and echo. The important application is the speech enhancement, which is done to remove suppressed noises and echoes taken by a microphone, beside preferred speech. Accordingly, the microphone signal has to be cleaned using digital signal processing DSP tools before it is played out, transmitted, or stored. Engineers have so far tried different approaches to improving the speech by get back the desired speech signal from the noisy observations. Especially Mobile communication, so in this paper will do reconstruction of the speech signal, observed in additive background noise, using the Kalman filter technique to estimate the parameters of the Autoregressive Process (AR) in the state space model and the output speech signal obtained by the MATLAB. The accurate estimation by Kalman filter on speech would enhance and reduce the noise then compare and discuss the results between actual values and estimated values which produce the reconstructed signals.

Keywords: autoregressive process, Kalman filter, Matlab, noise speech

Procedia PDF Downloads 348

Authors: Luvindran Sugumaran, Mohd Nashrul Mohd Zubir, Kazi Md Salim Newaz, Tuan Zaharinie Tuan Zahari, Suazlan Mt Aznam, Aiman Mohd Halil

Abstract:

With the fast growth of integrated circuits and the trend towards making electronic devices smaller, the heat dissipation load of electronic devices has continued to go over the limit. The high heat flux element would not only harm the operation and lifetime of the equipment but would also impede the performance upgrade brought about by the iteration of technological updates, which would have a direct negative impact on the economic and production cost benefits of rising industries. Hence, in high-tech industries like radar, information and communication, electromagnetic power, and aerospace, the development and implementation of effective heat dissipation technologies were urgently required. Pool boiling is favored over other cooling methods because of its capacity to dissipate a high heat flux at a low wall superheat without the usage of mechanical components. Enhancing the pool boiling performance by increasing the heat transfer coefficient via surface modification techniques has received a lot of attention. There are several surface modification methods feasible today, but the stability and durability of surface modification are the greatest priority. Thus, laser machining is an interesting choice for surface modification due to its low production cost, high scalability, and repeatability. In this study, different patterns of laser-processed copper surfaces are fabricated to investigate the nucleate pool boiling heat transfer performance of distilled water. The investigation showed that there is a significant enhancement in the pool boiling heat transfer performance of the laser-processed surface compared to the reference surface due to the notable increase in nucleation frequency and nucleation site density. It was discovered that the heat transfer coefficients increased when both the surface area ratio and the ratio of peak-to-valley height of the microstructure were raised. It is believed that the development of microstructures on the surface as a result of laser processing is the primary factor in the enhancement of heat transfer performance.

Keywords: heat transfer coefficient, laser processing, micro structured surface, pool boiling

Procedia PDF Downloads 93

Authors: Aristeidis Samitas, Stathis Polyzos

Abstract:

As the UK and the EU prepare to start negotiations for Brexit, it is important for both sides to comprehend the full extent of the consequences of this process. In this paper, we employ an object oriented simulation framework in order to test for the short-term and long-term effects of Brexit on both sides of the Channel. The relative strength of the UK economy and the banking sector vis-à-vis the EU is taken under consideration. Our results confirm predictions in the relevant literature regarding the output cost of Brexit, with particular emphasis on the EU. Furthermore, we show that financial stability is also an important issue on both sides, with the banking system suffering significant losses, particularly over the longer term. Our findings suggest that policymakers should be extremely careful in handling Brexit negotiations, making sure to consider dynamic effects that may be caused by UK bank assets moving to the EU after Brexit. The model results show that, as the UK banking system loses its assets, the end state of the UK economy is deteriorated while the end state of EU economy is improved.

Keywords: Banking Crises, Brexit, Financial Stability, VBanking

Procedia PDF Downloads 281

Authors: Mustafa Gulsen, Nihan Pekyavas, Emine Atıcı

Abstract:

Purpose: The aim of this study is to investigate the effects of Kinesio taping on postural stability and in young soccer players. Subjects and Methods: 62 volunteered soccer players from Cayyolu Sports Club were included in our study. Permissions were also taken from the club directors about the inclusion of their players to our study. Soccer players between the age of 12 and 16 were included in our study. Players that had previous injury on lower extremities were excluded from the study. Players were randomly divided into two groups: Kinesio taping (KT) (n=31), and control group (n = 31). KT application including gastrocnemius and quadriceps femoris muscle facilitation techniques were applied to the first group. A rest time for 45 minutes was given in order to see the best effectiveness of the tape. The second group was set as the control group and no application was made. All participants were assessed before the application and 45 minutes later. In order to provide the double-blind design of the study, an experienced physiotherapist has done the assessments and another experienced physiotherapist has done the taping. The patients were randomly assigned to one of the two groups using an online random allocation software program. Postural stability was assessed by using Tetrax Interactive Balance System. Thermographic assessment was done by using FLIR E5 (FLIR Systems AB, Sweden) thermal camera in order to see which muscles have the most thermal activity while maintaining postural stability. Results: Statistically significant differences were found in all assessment parameters in both Kinesio Taping and control groups (all p<0.05) except thermal imaging of dominant gastrocnemius muscle results (p=0.668) (Table 1). In comparison of the two groups, statistically significant differences were found in all parameters (all p<0.05). Conclusion: In this study, we investigated the effects of Kinesio taping on postural stability in young soccer players and found that KT application on Quadriceps and Gastrocnemius muscles may have decreased the risk of falling more than the control group. According to thermal imaging assessments, both Quadriceps and Gastrocnemius muscles may be active in maintaining postural stability but in KT group, the temperature of these muscles are higher which leads us to think that they are more activated.

Keywords: Kinesio taping, fall risk, muscle temperature, postural stability

Procedia PDF Downloads 244

Authors: N. Yang, R. Linforth, I. Fisk

Abstract:

The influence of food processing and choice of flavour solvent was investigated using biscuits prepared with vanillin flavour as an example. Powder vanillin either was added directly into the dough or dissolved into flavour solvent then mixed into the dough. The impact of two commonly used flavour solvents on food quality was compared: propylene glycol (PG) or triacetin (TA). The analytical approach for vanillin detection was developed by chromatography (HPLC-PDA), and the standard extraction method for vanillin was also established. The results indicated the impact of solvent choice on vanillin level during biscuit preparation. After baking, TA as a more heat resistant solvent retained more vanillin than PG, so TA is a better solvent for products that undergo a heating process. The results also illustrated the impact of mixing and baking on vanillin stability in the matrices. The average loss of vanillin was 33% during mixing and 13% during baking, which indicated that the binding of vanillin to fat or flour before baking might cause larger loss than evaporation loss during baking.

Keywords: biscuit, flavour stability, food quality, vanillin

Procedia PDF Downloads 509

Authors: F. Adjel, S. Almi, D. Barkat

Abstract:

The synergistic solvent extraction of nickel ion from 0.33 mol dm^-3 Na2SO4 aqueous solutions with capric acid (HL) in the absence and presence of Tri-n-octylphosphine oxide (TOPO) in chloroform at 25°C, has been studied. The extracted species when the capric acid compound was used alone, is NiL2 and NiL2(HL). In the presence of TOPO, a remarkable enhancement on the extraction of nickel (II) with 0.02 mol dm^-3 capric acid was observed upon the addition of 0.00125 and 0.0025 mol dm^-3 TOPO in chloroform. From a synergistic extraction- equilibrium study, the synergistic enhancement was ascribed to the adduct formation NiL2(TOPO) and NiL2(HL)(TOPO). The TOPO-HL interaction strongly influences the synergistic extraction efficiency. The synergistic extraction stoichiometry of nickel (II) with capric acid and TOPO is studied with the methods of slope analysis. The equilibrium constants were determined.

Keywords: solvent extraction, nickel(II), capric acid, TOPO, synergism

Procedia PDF Downloads 602

Authors: Khawar Ali

Abstract:

We present the numerical study of unsteady hydromagnetic (MHD) flow and heat transfer characteristics of a viscous incompressible electrically conducting water-based hybrid metallic nanofluid (containing Cu-Au/ H₂O nanoparticles) between two orthogonally moving porous coaxial disks with suction. Different from the classical shooting methodology, we employ a combination of a direct and an iterative method (SOR with optimal relaxation parameter) for solving the sparse systems of linear algebraic equations arising from the FD discretization of the linearized self similar nonlinear ODEs. Effects of the governing parameters on the flow and heat transfer are discussed and presented through tables and graphs. The findings of the present investigation may be beneficial for the electronic industry in maintaining the electronic components under effectiveand safe operational conditions.

Keywords: heat transfer enhancement, hybrid metallic nanofluid, viscous dissipation and joule heating effect , Two dimensional flow

Procedia PDF Downloads 233

Authors: R. Kiran, B. R. Lakshmikantha, R. V. Parimala

Abstract:

Secure operation of power systems requires monitoring of the system operating conditions. Phasor measurement units (PMU) are the device, which uses synchronized signals from the GPS satellites, and provide the phasors information of voltage and currents at a given substation. The optimal locations for the PMUs must be determined, in order to avoid redundant use of PMUs. The objective of this paper is to make system observable by using minimum number of PMUs & the implementation of stability software at 22OkV grid for on-line estimation of the power system transfer capability based on voltage and thermal limitations and for security monitoring. This software utilizes State Estimator (SE) and synchrophasor PMU data sets for determining the power system operational margin under normal and contingency conditions. This software improves security of transmission system by continuously monitoring operational margin expressed in MW or in bus voltage angles, and alarms the operator if the margin violates a pre-defined threshold.

Keywords: state estimator (SE), flexible ac transmission systems (FACTS), optimal location, phasor measurement units (PMU)

Procedia PDF Downloads 413

Authors: Rahime Filiz Kiremit

Abstract:

This study identifies six different articles to explain which strategies are most effective for kindergarten English Language Learners. The literature review project has information about six different research articles, purpose of the studies, and results of the studies. There are several strategies can be used for ELL students to help them to develop their English language skills. Some articles mention technology as a multimedia integrated into the curriculum, some of them mention writing as a method of learning English as a second language. However, they all have a common strategy that is shared reading. According to these six articles, shared reading has a big role of ELL students’ language developmental process. All in all, read-aloud with multimedia enhancement strategy is the best strategy to use in the classroom, because this strategy is based on shared reading and also integrated with technology.

Keywords: bilingual education, effective strategies, english language learners, kindergarten

Procedia PDF Downloads 297