Search results for: hybrid rocket motor

Authors: Norshazmira Mat Azmi, Sayidal El Fatimah Masnan, Shatirah Akib

Abstract:

More than 70% of the Earth is covered by oceans, which are considered to possess boundless renewable energy, such as tidal energy, tidal current energy, wave energy, thermal energy, and chemical energy. The hybrid system help in improving the economic and environmental sustainability of renewable energy systems to fulfill the energy demand. The concept of hybridizing renewable energy is to meet the desired system requirements, with the lowest value of the energy cost. This paper propose a hybrid power generation system suitable for remote area application and highlight the impact of surface waves on turbine design and performance, and the importance of understanding the site-specific wave conditions.

Keywords: marine current energy, tidal turbines, wave turbine, renewable energy, surface waves, hydraulic flume experiments, instantaneous wave phase

Procedia PDF Downloads 383

Authors: Aydin Teymourifar, Gurkan Ozturk

Abstract:

In this paper, a hybrid distributed algorithm has been suggested for the multi-objective job shop scheduling problem. Many new approaches are used at design steps of the distributed algorithm. Co-evolutionary structure of the algorithm and competition between different communicated hybrid algorithms, which are executed simultaneously, causes to efficient search. Using several machines for distributing the algorithms, at the iteration and solution levels, increases computational speed. The proposed algorithm is able to find the Pareto solutions of the big problems in shorter time than other algorithm in the literature. Apache Spark and Hadoop platforms have been used for the distribution of the algorithm. The suggested algorithm and implementations have been compared with results of the successful algorithms in the literature. Results prove the efficiency and high speed of the algorithm.

Keywords: distributed algorithms, Apache Spark, Hadoop, job shop scheduling, multi-objective optimization

Procedia PDF Downloads 338

Authors: Tolulope A. Olukunle

Abstract:

Plastic waste management has emerged as one of the greatest challenges facing developing countries. This paper describes the design of various components of a plastic shredder. This machine is widely used in industries and recycling plants. The introduction of plastic shredder machine will promote reduction of post-consumer plastic waste accumulation and serves as a system for wealth creation and empowerment through conversion of waste into economically viable products. In this design research, a 10 kW electric motor with a rotational speed of 500 rpm was chosen to drive the shredder. A pulley size of 400 mm is mounted on the electric motor at a distance of 1000 mm away from the shredder pulley. The shredder rotational speed is 300 rpm.

Keywords: design, machine, plastic waste, recycling

Procedia PDF Downloads 294

Authors: Shu Yin, Zhiyang Ding, Jianzhong Huang, Xiaojun Ruan, Xiaomin Zhu, Xiao Qin

Abstract:

Since large-scale and data-intensive applications have been widely deployed, there is a growing demand for high-performance storage systems to support data-intensive applications. Compared with traditional storage systems, next-generation systems will embrace dedicated processor to reduce computational load of host machines and will have hybrid combinations of different storage devices. The advent of flash- memory-based solid state disk has become a critical role in revolutionizing the storage world. However, instead of simply replacing the traditional magnetic hard disk with the solid state disk, it is believed that finding a complementary approach to corporate both of them is more challenging and attractive. This paper explores an idea of active storage, an emerging new storage configuration, in terms of the architecture and design, the parallel processing capability, the cooperation of other machines in cluster computing environment, and a disk configuration, the hybrid combination of different types of disk drives. Experimental results indicate that the proposed HcDD achieves better I/O performance and longer storage system lifespan.

Keywords: arallel storage system, hybrid storage system, data inten- sive, solid state disks, reliability

Procedia PDF Downloads 419

Authors: F. J. Adeyeye, D. Eni, K. M. Okedoye

Abstract:

In this paper we present a Hybrid of Adomian decomposition method (ADM). This is the substitution of a One-step method of Taylor’s series approximation of orders I and II, into the nonlinear part of Adomian decomposition method resulting in a convergent series scheme. This scheme is applied to solve some Logistic problems represented as Abelian differential equation and the results are compared with the actual solution and Runge-kutta of order IV in order to ascertain the accuracy and efficiency of the scheme. The findings shows that the scheme is efficient enough to solve logistic problems considered in this paper.

Keywords: Adomian decomposition method, nonlinear part, one-step method, Taylor series approximation, hybrid of Adomian polynomial, logistic problem, Malthusian parameter, Verhulst Model

Procedia PDF Downloads 373

Authors: Adel Salem Bahakeem, Ahmad Jamal, Mir Md. Maruf Morshed, Elwaleed Awad Khidir

Abstract:

Direct Current (DC) servo motors, or simply DC motors, play an important role in many industrial applications such as manufacturing of plastics, precise positioning of the equipment, and operating computer-controlled systems where speed of feed control, maintaining the position, and ensuring to have a constantly desired output is very critical. These parameters can be controlled with the help of control systems such as the Proportional Integral Derivative (PID) controller. The aim of the current work is to investigate the effects of Proportional (P) and Integral (I) controllers on the steady state and transient response of the DC motor. The controller gains are varied to observe their effects on the error, damping, and stability of the steady and transient motor response. The current investigation is conducted experimentally on a servo trainer CE 110 using analog PI controller CE 120 and theoretically using Simulink in MATLAB. Both experimental and theoretical work involves varying integral controller gain to obtain the response to a steady-state input, varying, individually, the proportional and integral controller gains to obtain the response to a step input function at a certain frequency, and theoretically obtaining the proportional and integral controller gains for desired values of damping ratio and response frequency. Results reveal that a proportional controller helps reduce the steady-state and transient error between the input signal and output response and makes the system more stable. In addition, it also speeds up the response of the system. On the other hand, the integral controller eliminates the error but tends to make the system unstable with induced oscillations and slow response to eliminate the error. From the current work, it is desired to achieve a stable response of the servo motor in terms of its angular velocity subjected to steady-state and transient input signals by utilizing the strengths of both P and I controllers.

Keywords: DC servo motor, proportional controller, integral controller, controller gain optimization, Simulink

Procedia PDF Downloads 84

Authors: Sadaf Karkoodi, Hassan Karampour

Abstract:

There is a growing interest in the construction industry towards hybrid systems. The hybrid systems use construction materials such as timber, steel, and concrete smartly, can be prefabricated, and are cost-effective and sustainable solutions to an industry targeting reduced carbon footprint. Moreover, in case of periodical shortage in timber resources, reusable and waste wood such as fibres can be used in the hybrid modules, which facilitates the circular economy. In this research, a hybrid frame is proposed and experimentally validated by introducing dried wood fibre products inside cold-formed steel square hollow sections without using any adhesives. As such, fibre-filled steel tubular (FFST) columns, beams, and 2D frames are manufactured and tested. The results show that the FFST columns have stiffness and strength 44% and 55% higher than cold-formed steel columns, respectively. The bearing strength of the FFST beams shows an increase of 39.5% compared to steel only. The flexural stiffness and strength of the FFST beams are 8.5% and 28% higher than the bare steel beams, respectively. The FFST frame depicted an 18.4% higher ultimate load capacity than the steel-only frame under a mid-point concentrated load. Moreover, the FFST beam-to-column bolted connection showed high ductile performance. The initial results and the proposed simple manufacturing process suggest that the proposed FFST concept can be upscaled and used in real structures.

Keywords: wood fibre, reusing wood, fibre-filled steel, hybrid construction

Procedia PDF Downloads 47

Authors: Soheil Heydari, Ailar Hajimohammadi, Nasser Khalili

Abstract:

Polystyrene, being made from a monomer called styrene, is a rigid and easy-to mould polymer that is widely used for many applications, from foam packaging to disposable containers. Considering that the degradation of waste polystyrene takes up to 500 years, there is an urgent need for a sustainable application for waste polystyrene. This study evaluates the application of waste polystyrene as an asphalt modifier. The inclusion of waste plastics in asphalt is either practised by the dry process or the wet process. In the dry process, plastics are added straight into the asphalt mixture and in the wet process, they are mixed and digested into bitumen. In this article, polystyrene was used as an asphalt modifier in a dry process. However, the mixing process is precisely designed to make sure that the polymer is melted and modified in the binder. It was expected that, due to the rigidity of polystyrene, it will have positive effects on the permanent deformation of the asphalt mixture. Therefore, different mixtures were manufactured with different contents of polystyrene and Marshall specimens were manufactured, and dynamic creep tests were conducted to evaluate the permanent deformation of the modification. This is a commonly repeated loading test conducted at different stress levels and temperatures. Loading cycles are applied to the AC specimen until failure occurs; with the amount of deformation constantly recorded the cumulative, permanent strain is determined and reported as a function of the number of cycles. Also, to our best knowledge, hybrid mixes of polystyrene with crumb rubber and low-density polyethylene were made and compared with a polystyrene-modified mixture. The test results of this study showed that the hybrid mix of polystyrene and low-density polyethylene has the highest resistance against permanent deformation. However, the polystyrene-modified mixture outperformed the hybrid mix of polystyrene and crumb rubber, and both demonstrated way lower permanent deformation than the unmodified specimen.

Keywords: permanent deformation, waste plastics, polystyrene, hybrid plastics, hybrid mix, hybrid modification, dry process

Procedia PDF Downloads 68

Authors: Eugene Stepanov, Arkadi Ponossov

Abstract:

Ordinary differential equations with switching nonlinearities constitute a very useful tool in many applications. The solutions of such equations can usually be calculated analytically if they cross the discontinuities transversally. Otherwise, one has trajectories that slides along the discontinuity, and the calculations become less straightforward in this case. For instance, one of the problems one faces is non-uniqueness of the sliding modes. In the presentation, it is proposed to apply the theory of hybrid dynamical systems to calculate the solutions that are ‘hidden’ in the discontinuities. Roughly, one equips the underlying switched system with an explicitly designed discrete dynamical system (‘automaton’), which governs the dynamics of the switched system. This construction ‘splits’ the dynamics, which, as it is shown in the presentation, gives uniqueness of the resulting hybrid trajectories and at the same time provides explicit formulae for them. Projecting the hybrid trajectories back onto the original continuous system explains non-uniqueness of its trajectories. The automaton is designed with the help of the attractors of the specially constructed adjoint dynamical system. Several examples are provided in the presentation, which supports the efficiency of the suggested scheme. The method can be of interest in control theory, gene regulatory networks, neural field models and other fields, where switched dynamics is a part of the analysis.

Keywords: hybrid dynamical systems, singular perturbation analysis, sliding modes, switched dynamics

Procedia PDF Downloads 139

Authors: Mohammad Arabi

Abstract:

The development of advanced technologies in the field of signal processing and vibration analysis has enabled more accurate analysis and fault detection in electrical systems. This research investigates the application of temporal and frequency features in detecting faults in electric motor bearings, aiming to enhance fault detection accuracy and prevent unexpected failures. The use of methods such as deep learning algorithms and neural networks in this process can yield better results. The main objective of this research is to evaluate the efficiency and accuracy of methods based on temporal and frequency features in identifying faults in electric motor bearings to prevent sudden breakdowns and operational issues. Additionally, the feasibility of using techniques such as machine learning and optimization algorithms to improve the fault detection process is also considered. This research employed an experimental method and random sampling. Vibration signals were collected from electric motors under normal and faulty conditions. After standardizing the data, temporal and frequency features were extracted. These features were then analyzed using statistical methods such as analysis of variance (ANOVA) and t-tests, as well as machine learning algorithms like artificial neural networks and support vector machines (SVM). The results showed that using temporal and frequency features significantly improves the accuracy of fault detection in electric motor bearings. ANOVA indicated significant differences between normal and faulty signals. Additionally, t-tests confirmed statistically significant differences between the features extracted from normal and faulty signals. Machine learning algorithms such as neural networks and SVM also significantly increased detection accuracy, demonstrating high effectiveness in timely and accurate fault detection. This study demonstrates that using temporal and frequency features combined with machine learning algorithms can serve as an effective tool for detecting faults in electric motor bearings. This approach not only enhances fault detection accuracy but also simplifies and streamlines the detection process. However, challenges such as data standardization and the cost of implementing advanced monitoring systems must also be considered. Utilizing temporal and frequency features in fault detection of electric motor bearings, along with advanced machine learning methods, offers an effective solution for preventing failures and ensuring the operational health of electric motors. Given the promising results of this research, it is recommended that this technology be more widely adopted in industrial maintenance processes.

Keywords: electric motor, fault detection, frequency features, temporal features

Procedia PDF Downloads 12

Authors: Hanan Mikhael Dawood, Afaneen Anwer Abood Al-Khazraji

Abstract:

The paper presents an investigation of field oriented control strategy of Permanent Magnet Synchronous Motor (PMSM) based on hardware in the loop simulation (HIL) over a wide speed range. A sensorless rotor position estimation using sliding mode observer for permanent magnet synchronous motor is illustrated considering the effects of magnetic saturation between the d and q axes. The cross saturation between d and q axes has been calculated by finite-element analysis. Therefore, the inductance measurement regards the saturation and cross saturation which are used to obtain the suitable id-characteristics in base and flux weakening regions. Real time matrix multiplication in Field Programmable Gate Array (FPGA) using floating point number system is used utilizing Quartus-II environment to develop FPGA designs and then download these designs files into development kit. dSPACE DS1103 is utilized for Pulse Width Modulation (PWM) switching and the controller. The hardware in the loop results conducted to that from the Matlab simulation. Various dynamic conditions have been investigated.

Keywords: magnetic saturation, rotor position estimation, sliding mode observer, hardware in the loop (HIL)

Procedia PDF Downloads 501

Authors: V. K. Tewari, M. Hussain, H. K. D. Gupta

Abstract:

B-Methylprednisolone-level-1-benefit (20%) usually given in paraplegia (but within 8hrs). Patients wait-long-duration for physiological-recovery. Intrathecal-Sodium-Nitroprusside(ITSNP) has been used-in vasospasm-due-to-subarachnoid-hemorrhage. ITSNP-has been studied-here for wide-window-period-range for-treatment, fast-recovery/affordability. 2- for acute-cases-and 1-mechanism-for chronic-cases, which-are-interrelated, are being-proposed-for-physiological-recovery. retrograde-neurotransmission, vasospasm and long-term-potentiation-(ltp) mechanisms are proposed here for recovery. It’s a case-control-prospective-study. 82paraplegia-patients(10patients taken as control-no superfusion or dextrose5% superfusion and 72patients as ITSNP-group). The mean time for superfusion was 14.11 days. ITSNP administered at a dosage of 0.2 mg/kg bo wt. Pre/post ITSNP monitored by SSEP/MEP. After-2-Hours in ITSNP-group Mean-Change-From-Baseline-Asia Motor/Sensory-Score 13.84%/13.10%, after-24-hours MOTOR-1.27-points decrease(3.77%) and SENSORY 10.5points-increase(6.22%)as compared to Control-group no-change noted upto 24-hours, At-7days ITSNP motor/sensory;11.56%/6.22% as compared to Control-group 7.60/4.48%, At-2-months in ITSNP 27.69%/6.22% as compared to Control-group 16.02/4.5%. SSEP/MEP-documented-improvements-noted. ITSNP, a-swift-acting-drug in treatment-of-paraplegia, is effective within-two-hours(mean-change-MOTOR-13.84% and SENSORY-13.10%) on-mean14.11th postparaplegia-day with a small-detrimental-response after-24-hours which-recovers-fast.

Keywords: paraplegias, intrathecal sodium nitroprusside, retrograde transmission, the 10, 000 fold effect, perforators, vasodilatations, long term potenciations

Procedia PDF Downloads 385

Authors: Elham Jelodari Mamaghani, Christian Prins, Haoxun Chen

Abstract:

In this paper, there is concentration on collaborative transportation planning (CTP) among multiple carriers with pickup and delivery requests and time windows. This problem is a vehicle routing problem with constraints from standard vehicle routing problems and new constraints from a real-world application. In the problem, each carrier has a finite number of vehicles, and each request is a pickup and delivery request with time window. Moreover, each carrier has reserved requests, which must be served by itself, whereas its exchangeable requests can be outsourced to and served by other carriers. This collaboration among carriers can help them to reduce total transportation costs. A mixed integer programming model is proposed to the problem. To solve the model, a hybrid algorithm that combines Genetic Algorithm and Simulated Annealing (GASA) is proposed. This algorithm takes advantages of GASA at the same time. After tuning the parameters of the algorithm with the Taguchi method, the experiments are conducted and experimental results are provided for the hybrid algorithm. The results are compared with those obtained by a commercial solver. The comparison indicates that the GASA significantly outperforms the commercial solver.

Keywords: centralized collaborative transportation, collaborative transportation with pickup and delivery, collaborative transportation with time windows, hybrid algorithm of GA and SA

Procedia PDF Downloads 368

Authors: Tarek Aly

Abstract:

Introduction: Maintenance of the length, providing rotational stability, and preserving functional range of forearm motion is the mainstay of both bone forearm fractures treatment. Conservative treatment in older children may lead to malunion with poor remodeling capacity. Recent studies emphasized that the rate of complications with IM nailing was obviously increased in old children. Open reduction and internal fixation have been criticized for the amount of soft tissue dissection and periosteal stripping needed for fixation and excessive scar formation. The aim of this study was to evaluate the anatomical and functional outcomes of hybrid fixation in the treatment of closed proximal radius and ulna fractures in adolescents between 12 and 17 years of age. Patients and Methods: 30 cases of diaphyseal both bone forearm fractures treated with hybrid fixation (Nail radius – Plate ulna) and were available for a follow-up period of fewer than 24 months. Results: Clinically, 72% of cases had an excellent function, 22% had a good function, 4% had a fair function, and 2% had a poor function. Radiologically, signs of the union had appeared in the radius 2weeks earlier than in the ulna in 55% of cases. Conclusion: A hybrid fixation technique in adolescent proximal both-bones forearm fractures could be a viable option in managing these injuries.

Keywords: hyprid fixation, both bones, forearm, fractures

Procedia PDF Downloads 73

Authors: Rama Bhargava

Abstract:

In the current paper, numerical simulation has been performed for the two-dimensional time dependent Pennes’ heat transfer model which is solved for irregular diseased tumor cells. An elliptic cryoprobe of varying sizes is taken at the center of the computational domain in such a manner that the location of the probe is fixed throughout the computation. The phase transition occurs due to the effect of probe with infusion of different nanoparticles Au, Al₂O₃, Fe₃O₄. The cooling performance of these nanoparticles injected at very low temperature, has been studied by implementing a hybrid FEM/EFGM method in which the whole domain is decomposed into two subdomains. The results are shown in terms of temperature profile inside the computational domain. Rate of cooling is obtained for various nanoparticles and it is observed that infusion of Au nanoparticles is very much efficient in increasing the heating rate than other nanoparticles. Such numerical scheme has direct applications where the domain is irregular.

Keywords: cryosurgery, hybrid EFGM/FEM, nanoparticles, simulation

Procedia PDF Downloads 216

Authors: Ana Munguia, Gerardo Ortiz, Guadalupe Gonzalez, Fiacro Jimenez

Abstract:

Parkinson's disease (PD) is a neurodegenerative disorder that causes motor and cognitive symptoms. The first-choice treatment for these patients is pharmacological, but this generates several side effects. Because of that new treatments were introduced such as Repetitive Transcranial Magnetic Stimulation (rTMS) in order to improve the life quality of the patients. Several studies suggest significant changes in motor symptoms. However, there is a great diversity in the number of pulses, amplitude, frequency and stimulation targets, which results in inconsistent data. In addition, these studies do not have an analysis of the neuropsychological effects of the treatment. The main purpose of this study is to evaluate the impact of rTMS on the cognitive performance of 6 patients with H&Y III and IV (45-65 years, 3 men and 3 women). An initial neuropsychological and neurological evaluation was performed. Patients were randomized into two groups; in the first phase one received rTMS in the supplementary motor area, the other group in the dorsolateral prefrontal cortex contralateral to the most affected hemibody. In the second phase, each group received the stimulation in the area that he had not been stimulated previously. Reassessments were carried out at the beginning, at the end of each phase and a follow-up was carried out 6 months after the conclusion of the stimulation. In these preliminary results, it is reported that there's no statistically significant difference before and after receiving rTMS in the neuropsychological test scores of the patients, which suggests that the cognitive performance of patients is not detrimental. There are even tendencies towards an improvement in executive functioning after the treatment. What added to motor improvement, showed positive effects in the activities of the patients' daily life. In a later and more detailed analysis, will be evaluated the effects in each of the patients separately in relation to the functionality of the patients in their daily lives.

Keywords: Parkinson's disease, rTMS, cognitive, treatment

Procedia PDF Downloads 126

Authors: Germán Gálvez-García, Marta Lavin, Javiera Peña, Javier Albayay, Claudio Bascour, Jesus Fernandez-Gomez, Alicia Pérez-Gálvez

Abstract:

We studied the effectiveness of response inhibition in movements with different degrees of motor complexity when they were executed in isolation and alternately. Sixteen participants performed the Stroop task which was used as a measure of response inhibition. Participants responded by lifting the index finger and reaching the screen with the same finger. Both actions were performed separately and alternately in different experimental blocks. Repeated measures ANOVAs were used to compare reaction time, movement time, kinematic errors and Movement errors across conditions (experimental block, movement, and congruency). Delta plots were constructed to perform distributional analyses of response inhibition and accuracy rate. The effectiveness of response inhibition did not show difference when the movements were performed in separated blocks. Nevertheless, it showed differences when they were performed alternately in the same experimental block, being more effective for the lifting action. This could be due to a competition of the available resources during a more complex scenario which also demands to adopt some strategy to avoid errors.

Keywords: response inhibition, motor complexity, Stroop task, delta plots

Procedia PDF Downloads 374

Authors: Davide Cocchi, Andrea Zucchelli, Luca Raimondi, Maria Brugo Tommaso

Abstract:

The increasing attention is given to the issues of environmental pollution and climate change is exponentially stimulating the development of electrically propelled vehicles powered by renewable energy, in particular, the solar one. Given the small amount of solar energy that can be stored and subsequently transformed into propulsive energy, it is necessary to develop vehicles with high mechanical, electrical and aerodynamic efficiencies along with reduced masses. The reduction of the masses is of fundamental relevance especially for the unsprung masses, that is the assembly of those elements that do not undergo a variation of their distance from the ground (wheel, suspension system, hub, upright, braking system). Therefore, the reduction of unsprung masses is fundamental in decreasing the rolling inertia and improving the drivability, comfort, and performance of the vehicle. This principle applies even more in solar propelled vehicles, equipped with an electric motor that is connected directly to the wheel hub. In this solution, the electric motor is integrated inside the wheel. Since the electric motor is part of the unsprung masses, the development of compact and lightweight solutions is of fundamental importance. The purpose of this research is the design development and optimization of a CFRP 16 wheel hub motor for solar propulsion vehicles that can carry up to four people. In addition to trying to maximize aspects of primary importance such as mass, strength, and stiffness, other innovative constructive aspects were explored. One of the main objectives has been to achieve a high geometric packing in order to ensure a reduced lateral dimension, without reducing the power exerted by the electric motor. In the final solution, it was possible to realize a wheel hub motor assembly completely comprised inside the rim width, for a total lateral overall dimension of less than 100 mm. This result was achieved by developing an innovative connection system between the wheel and the rotor with a double purpose: centering and transmission of the driving torque. This solution with appropriate interlocking noses allows the transfer of high torques and at the same time guarantees both the centering and the necessary stiffness of the transmission system. Moreover, to avoid delamination in critical areas, evaluated by means of FEM analysis using 3D Hashin damage criteria, electrospun nanofibrous mats have been interleaved between CFRP critical layers. In order to reduce rolling resistance, the rim has been designed to withstand high inflation pressure. Laboratory tests have been performed on the rim using the Digital Image Correlation technique (DIC). The wheel has been tested for fatigue bending according to E/ECE/324 R124e.

Keywords: composite laminate, delamination, DIC, lightweight vehicle, motor hub wheel, nanofiber

Procedia PDF Downloads 188

Authors: Parag Nihawan, Ravinder Singh Bhatia, Dinesh Kumar Jain

Abstract:

Industrial drives are source of serious power quality problems. In this, two typical industrial drives have been dealt with, namely, FOC induction motor drives and DTC induction motor drive. The Z-source inverter is an emerging topology of power electronic converters which is capable of buck boost characteristics. The performances of different control methods based Z-source inverters feeding these industrial drives have been investigated, in this work. The test systems have been modeled and simulated in MATLAB/SIMULINK. The results obtained after carrying out these simulations have been used to draw the conclusions.

Keywords: Z-source inverter, total harmonic distortion, direct torque control, field orientation control

Procedia PDF Downloads 556

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 207

Authors: H. K. Shivanand, A. Yogananda

Abstract:

The objective of present investigation is to study the effect of reinforcements on the wear properties of E-Glass short fibers and Flyash reinforced Al 8011 hybrid metal matrix composites. The alloy of Al 8011 reinforced with E-glass and fly ash particulates are prepared by simple stir casting method. The MMC is obtained for different composition of E-glass and flyash particulates (varying E-glass with constant fly ash and varying flyash with constant E-glass percentage). The wear results of ascast hybrid composites with different compositions of reinforcements at varying sliding speeds and different loads are discussed. The results reveals that as the percentage of reinforcement increases wear rate will decrease.

Keywords: metal matrix composites, aluminum alloy 8011, stir casting, wear test

Procedia PDF Downloads 329

Authors: S. S. Ghodsi, M. H. Mehrabi, Zainah Ibrahim, Meldi Suhatril

Abstract:

This research examines the performance of a hybrid passive control device for enhancing the seismic response of steel frame structures. The device design comprises a damper which employs a viscoelastic material to control both shear and axial strain. In the design, energy is dissipated through the shear strain of a two-layer system of viscoelastic pads which are located between steel plates. In addition, viscoelastic blocks have been included on either side of the main shear damper which obtains compressive strains in the viscoelastic blocks. These dampers not only dissipate energy but also increase the stiffness of the steel frame structure, and the degree to which they increase the stiffness may be controlled by the size and shape. In this research, the cyclical behavior of the damper was examined both experimentally and numerically with finite element modeling. Cyclic loading results of the finite element modeling reveal fundamental characteristics of this hybrid viscoelastic damper. The results indicate that incorporating a damper of the design can significantly improve the seismic performance of steel frame structures.

Keywords: cyclic loading, energy dissipation, hybrid damper, passive control system, viscoelastic damper

Procedia PDF Downloads 174

Authors: Suchana Marahatta, Sabina Bhattarai, Bishnu Hari Paudel, Dilip Thakur

Abstract:

Background: Every year thousands of patients develop nerve damage and disabilities as a result of leprosy which can be prevented by early detection and treatment. So, early detection and treatment of nerve function impairment is of paramount importance in leprosy. Objectives: To assess the electrophysiological pattern of the peripheral nerves in leprosy patients and to compare it with clinical assessment tools. Materials and Methods: In this comparative cross-sectional study, 74 newly diagnosed leprosy patients without reaction were enrolled. They underwent thorough evaluation for peripheral nerve function impairment using clinical tests [i.e. nerve palpation (NP), monofilament (MF) testing, voluntary muscle testing (VMT)] and nerve conduction study (NCS). Clinical findings were compared with that of NCS using SPSS version 11.5. Results: NCS was impaired in 43.24% of leprosy patient at the baseline. Among them, sensory NCS was impaired in more patients (32.4%) in comparison to motor NCS (20.3%). NP, MF, and VMT were impaired in 58.1%, 25.7%, and 9.4% of the patients, respectively. Maximum concordance of monofilament testing and sensory NCS was found for sural nerve (14.7%). Likewise, the concordance of motor NP and motor NCS was the maximum for ulnar nerve (14.9%). When individual parameters of the NCS were considered, amplitude was found to be the most frequently affected parameter for both sensory and motor NCS. It was impaired in 100% of cases with abnormal NCS findings. Conclusion: Since there was no acceptable concordance between NCS findings and clinical findings, we should consider NCS whenever feasible for early detection of neuropathy in leprosy. The amplitude of both sensory nerve action potential (SNAP) and compound nerve action potential (CAMP) could be important determinants of the abnormal NCS if supported by further studies.

Keywords: leprosy, nerve function impairment, neuropathy, nerve conduction study

Procedia PDF Downloads 291

Authors: Dace Aleksandraviča

Abstract:

The paper presents a theoretical exploration of the emerging field of 21st-century ecolinguistics, which examines the multi-faceted relationship between language, ecology, and identity in our rapidly changing global landscape. In an era characterized by unprecedented linguistic and cultural hybridity, understanding the interplay between language and environment is paramount. This paper delves into the concept of hybrid identities, examining how individuals negotiate their linguistic and cultural affiliations within diverse ecological contexts based on relevant prior contributions in the field. Drawing upon interdisciplinary perspectives from linguistics, environmental studies, and cultural studies, the research investigates the ways in which language shapes and is shaped by environmental realities. The abstract underscores the importance of ecolinguistic approaches in fostering environmental stewardship and promoting sustainable practices. By acknowledging the intrinsic link between language, culture, and ecology, it becomes possible to cultivate a deeper appreciation for linguistic diversity and empower individuals to navigate their hybrid identities in a rapidly changing world. In line with that, the paper hopes to contribute to the growing body of literature on ecolinguistics and offer insights into how language can serve as a tool for both environmental conservation and cultural revitalization.

Keywords: ecolinguistics, hybrid identities, language, globalization

Procedia PDF Downloads 23

Authors: Liqin Zhang, Liang Yan

Abstract:

This paper addresses the speed synchronization control problem for a network-based multi-motor system from the perspective of cluster consensus theory. Each motor is considered as a single agent connected through fixed and undirected network. This paper presents an improved control protocol from three aspects. First, for the purpose of improving both tracking and synchronization performance, this paper presents a distributed leader-following method. The improved control protocol takes the importance of each motor’s speed into consideration, and all motors are divided into different groups according to speed weights. Specifically, by using control parameters optimization, the synchronization error and tracking error can be regulated and decoupled to some extent. The simulation results demonstrate the effectiveness and superiority of the proposed strategy. In practical engineering, the simplified models are unrealistic, such as single-integrator and double-integrator. And previous algorithms require the acceleration information of the leader available to all followers if the leader has a varying velocity, which is also difficult to realize. Therefore, the method focuses on an observer-based variable structure algorithm for consensus tracking, which gets rid of the leader acceleration. The presented scheme optimizes synchronization performance, as well as provides satisfactory robustness. What’s more, the existing algorithms can obtain a stable synchronous system; however, the obtained stable system may encounter some disturbances that may destroy the synchronization. Focus on this challenging technological problem, a state-dependent-switching approach is introduced. In the presence of unmeasured angular speed and unknown failures, this paper investigates a distributed fault-tolerant consensus tracking algorithm for a group non-identical motors. The failures are modeled by nonlinear functions, and the sliding mode observer is designed to estimate the angular speed and nonlinear failures. The convergence and stability of the given multi-motor system are proved. Simulation results have shown that all followers asymptotically converge to a consistent state when one follower fails to follow the virtual leader during a large enough disturbance, which illustrates the good performance of synchronization control accuracy.

Keywords: consensus control, distributed follow, fault-tolerant control, multi-motor system, speed synchronization

Procedia PDF Downloads 101

Authors: Constantinos Adamides, Petros Petrikkos

Abstract:

In the era of growing hybrid threats, small states find themselves in need to re-evaluate existing foreign and defense policies. The pressure to establishing or maintain a status of a reliable partner in the community in which they belong to, vis-à-vis their multilateral relations with other organisations and entities, small states may need to shift their policies in the field to accommodate security needs that are not only pertinent to their security, but also to that of the organisations (bloc) in which they interact. Unlike potential shortcomings in a small state’s mainstream security and defence framework where the threat would be limited to the state itself, in more contemporary times with dominating hybrid threats, the small states’ security shortcomings may also become a security problem for the bloc in which these states belong to. An indicative example is small states like Cyprus and Malta, which belong and 'interact' in the European Union. As a result, the nature of hybrid threats can be utilised to hurt bigger states in a bloc by exploiting the small states’ vulnerabilities and security gaps. Inevitably, both the defensive and foreign policy collaborations of small states with bigger states have been and are constantly re-evaluated to tackle and prevent such problems. In essence, the goal of this ‘re-evaluation’ aims to achieve a twofold goal: The first is the small states’ quest to appear as a reliable partner within the bloc, while the second is to avoid being the weakest security link in the bloc’s defence against hybrid threats. Indeed, the hybrid arena is a security area where they can excel in the bloc, despite the potential and expected conventional military deficiencies. This new environment prompts us to think security from the perspective of small states differently and in relation to their role as members or big organisations. The paper focuses on the case of Cyprus following its accession to the European Union and examines how a country that has had a very focused security orientation –not least due to its ongoing security problems– altered its foreign and defence policies within the European Union to ensure compliance with the rest of the bloc, while at the same time maximizing its role as a security player. Specifically, it examines the methods through which the country shifted its policies as well as the challenges and opportunities that emerged from these security shifts.

Keywords: Cyprus, defence, foreign policy, hybrid threats, ontological security, small states

Procedia PDF Downloads 114

Authors: Ahmad. A. Kardan, Amir Narimani, Foozhan Ataiefard

Abstract:

Recommender Systems have been developed to provide contents and services compatible to users based on their behaviors and interests. Due to information overload in online discussion forums and users diverse interests, recommending relative topics and threads is considered to be helpful for improving the ease of forum usage. In order to lead learners to find relevant information in educational forums, recommendations are even more needed. We present a hybrid thread recommender system for MOOC forums by applying social network analysis and association rule mining techniques. Initial results indicate that the proposed recommender system performs comparatively well with regard to limited available data from users' previous posts in the forum.

Keywords: association rule mining, hybrid recommender system, massive open online courses, MOOCs, social network analysis

Procedia PDF Downloads 265

Authors: Mohamed Zakaulla, A. R. Anwar Khan

Abstract:

Al6061 alloy base matrix, reinforced with particles of silicon carbide (10 wt %) and Graphite powder (1wt%), known as hybrid composites have been fabricated by liquid metallurgy route (stir casting technique) and optimized at different parameters like applied load, sliding speed and sliding distance by taguchi method. A plan of experiment generated through taguchi technique was used to perform experiments based on L27 orthogonal array. The developed ANOVA and regression equations are used to find the optimum coefficient of friction and wear under the influence of applied load, sliding speed and sliding distance. On the basis of “smaller the best” the dry sliding wear resistance was analysed and finally confirmation tests were carried out to verify the experimental results.

Keywords: analysis of variance, dry sliding wear, hybrid composite, orthogonal array, Taguchi technique

Procedia PDF Downloads 441

Authors: Wen-Chao Tang, Tang-Yi Liu, Ming Gao, Gang Xu, Hua-Yuan Yang

Abstract:

This study developed a method for teaching acupuncture manipulation in small groups optimized with the theory of motor learning. Sixty acupuncture students and their teacher participated in our research. Motion videos were recorded of their manipulations using the lifting-thrusting method. These videos were analyzed using Simi Motion software to acquire the movement parameters of the thumb tip. The parameter velocity curves along Y axis was used to generate small teaching groups clustered by a self-organized map (SOM) and K-means. Ten groups were generated. All the targeted instruction based on the comparative results groups as well as the videos of teacher and student was provided to the members of each group respectively. According to the theory and research of motor learning, the factors or technologies such as video instruction, observational learning, external focus and summary feedback were integrated into this teaching method. Such efforts were desired to improve and enhance the effectiveness of current acupuncture teaching methods in limited classroom teaching time and extracurricular training.

Keywords: acupuncture, group teaching, video instruction, observational learning, external focus, summary feedback

Procedia PDF Downloads 152

Authors: J. M. Counsell, Y. Khalid, M. J. Stewart

Abstract:

Achieving nearly zero carbon heating continues to be identified by UK government analysis as an important feature of any lowest cost pathway to reducing greenhouse gas emissions. Heat currently accounts for 48% of UK energy consumption and approximately one third of UK’s greenhouse gas emissions. Heat Networks are being promoted by UK investment policies as one means of supporting hybrid heat pump based solutions. To this effect the RISE (Renewable Integrated and Sustainable Electric) heating system project is investigating how an all-electric heating sourceshybrid configuration could play a key role in long-term decarbonisation of heat.  For the purposes of this study, hybrid systems are defined as systems combining the technologies of an electric driven air source heat pump, electric powered thermal storage, a thermal vessel and micro-heat network as an integrated system.  This hybrid strategy allows for the system to store up energy during periods of low electricity demand from the national grid, turning it into a dynamic supply of low cost heat which is utilized only when required. Currently a prototype of such a system is being tested in a modern house integrated with advanced controls and sensors. This paper presents the virtual performance analysis of the system and its design for a micro heat network with multiple dwelling units. The results show that the RISE system is controllable and can reduce carbon emissions whilst being competitive in running costs with a conventional gas boiler heating system.

Keywords: gas boilers, heat pumps, hybrid heating and thermal storage, renewable integrated and sustainable electric

Procedia PDF Downloads 397