Search results for: egg shape index

Authors: M. Asl. Dehghan, M. H. Daemi, S. Radmard, S. H. Nabavi

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Thin disk lasers are engineered for efficient thermal cooling and exhibit superior performance for this task. However the disk thickness and large pumped area make the use of this gain format in a resonator difficult when constructing a single-mode laser. Choosing an unstable resonator design is beneficial for this purpose. On the other hand, the low gain medium restricts the application of unstable resonators to low magnifications and therefore to a poor beam quality. A promising idea to enable the application of unstable resonators to wide aperture, low gain lasers is to couple a fraction of the out coupled radiation back into the resonator. The output coupling gets dependent on the ratio of the back reflection and can be adjusted independently from the magnification. The excitation of the converging wave can be done by the use of an external reflector. The resonator performance is numerically predicted. First of all the threshold condition of linear, V and 2V shape resonator is investigated. Results show that the maximum magnification is 1.066 that is very low for high quality purposes. Inserting an additional reflector covers the low gain. The reflectivity and the related magnification of a 350 micron Yb:YAG disk are calculated. The theoretical model was based on the coupled Kirchhoff integrals and solved numerically by the Fox and Li algorithm. Results show that with back reflection mechanism in combination with increasing the number of beam incidents on disk, high gain and high magnification can occur.

Keywords: unstable resonators, thin disk lasers, gain, external reflector

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Authors: V. C. Igwemezie, A. N. Mehmanparast

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The primary focus of this work is to understand how variations in the microstructure and cyclic waveform affect the corrosion fatigue crack growth (CFCG) in steel, especially in the Paris region of the da/dN vs. ΔK curve. This work is important because it provides fundamental information on the modelling, design, selection, and use of steels for various engineering applications in the marine environment. The corrosion fatigue tests data on normalized and thermomechanical control process (TMCP) ferritic-pearlitic steels by the authors were compared with several studies on different microstructures in the literature. The microstructures of these steels are radically different and general comparative fatigue crack growth resistance performance study on the effect of microstructure in these materials are very scarce and where available are limited to few studies. The results, for purposes of engineering application, in this study show less dependency of fatigue crack growth rate (FCGR) on yield strength, tensile strength, ductility, frequency and stress ratio in the range 0.1 – 0.7. The nature of the steel microstructure appears to be a major factor in determining the rate at which fatigue cracks propagate in the entire da/dN vs. ΔK sigmoidal curve. The study also shows that the sine wave shape is the most damaging fatigue waveform for ferritic-pearlitic steels. This tends to suggest that the test under sine waveform would be a conservative approach, regardless of the waveform for design of engineering structures.

Keywords: BS7910, corrosion-fatigue crack growth rate, cyclic waveform, microstructure, steel

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Authors: Rahma Adinda Sartika

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The use of technology in learning mathematics has received a positive response from both students and teachers, so many researchers have conducted research on this theme. Based on the findings carried out in this study, 807 documents relevant to this theme have been published in Scopus from 1995-2024. After going through the stages of identification, screening, eligibility, and including, the documents that meet the criteria are 227 documents. These documents are then analyzed using the bibliometric method so that it can be seen that the most published documents in the Scopus database occurred in 2020, with 38 documents, and the lowest was from 1996 to 2000 and 2004 to 2007, namely, no documents published. The highest number of citations is in documents published in 2018, with a total of 349 citations, so the h-index is higher than the others. The country that published the most documents relevant to this theme is Indonesia with a total of 91 documents. The second largest is the United States, with a total of 28 published documents, and the third largest is China, with a total of 15 documents. Indonesia and the United States have the most working relationships between countries compared to other countries. The focus of research related to this theme is 1) mathematics learning, 2) learning systems, 3) engineering education, 4) technology and 5) mathematical concepts.

Keywords: technology, bibliometric, mathematics learning, mathematical concepts

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Authors: Kavindan Balakrishnan

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Root cause Identification of the Vibration phenomenon in a feedwater pumping station was the main objective of this research. First, the mode shapes of the pumping structure were investigated using numerical and analytical methods. Then the flow pressure and streamline distribution in the pump sump were examined using C.F.D. simulation, which was hypothesized can be a cause of vibration in the pumping station. As the problem specification of this research states, the vibration phenomenon in the pumping station, with four parallel pumps operating at the same time and heavy vibration recorded even after several maintenance steps. They also specified that a relatively large amplitude of vibration exited by pumps 1 and 4 while others remain normal. As a result, the focus of this research was on determining the cause of such a mode of vibration in the pump station with the assistance of Finite Element Analysis tools and Analytical methods. Major outcomes were observed in structural behavior which is favorable to the vibration pattern phenomenon in the pumping structure as a result of this research. Behaviors of the numerical and analytical models of the pump structure have similar characteristics in their mode shapes, particularly in their 2nd mode shape, which is considerably related to the exact cause of the research problem statement. Since this study reveals several possible points of flow visualization in the pump sump model that can be a favorable cause of vibration in the system, there is more room for improved investigation on flow conditions relating to pump vibrations.

Keywords: vibration, simulation, analysis, Ansys, Matlab, mode shapes, pressure distribution, structure

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Authors: Ikram Kamal, Mohamed Blaghen

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Pollution caused by petroleum hydrocarbons in terrestrial and aquatic environment is a common phenomenon that causes significant ecological and social problems. Biosurfactant applications in the environmental industries are promising due to their biodegradability, low toxicity and effectiveness in enhancing biodegradation and solubilization of low solubility compounds. Currently, the main application is for enhancement of oil recovery and hydrocarbon bioremediation due to their biodegradability and low critical micelle concentration (CMC). In this study we have investigated the potential of bacterial strains collected aseptically from the lagoon Marchika (water and soil) in Nador, Morocco; for the production of biosurfactants. This study also aimed to optimize the biosurfactant production process by changing the variables that influence the type and amount of biosurfactant produced by these microorganisms such as: carbon sources and also other physical and chemical parameters such as temperature and pH. Emulsification index, methylene blue test and thin layer chromatography (TLC) revealed the ability of strains used in this study to produce compounds that could emulsify gasoline. In addition a GC/MS was used to separate and identify different biosurfactants purified.

Keywords: petroleum hydrocarbons, biosurfactant, biodegradability, critical micelle concentration, lagoon Marchika

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Authors: Mona Bakry Abdel Meguid Abdelaal

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Despite growing evidence that parental involvement in their adolescents’ lives affects the way they perceive the community around them, little effort has been made to address the importance of this relationship and how it affect the adolescents' interaction with their environment. Adolescents are influenced by their parents while they are growing up and this socialization process services to shape the adolescents sense of self, influencing not only how adolescents feel about themselves, but affecting how they interact with their surroundings. In order to effectively understand this issue, it is important to understand the adolescents’ understanding of healthy parental involvement in their lives, in addition to the obstacles that hinder their communication styles with their parents. Understanding parental involvement in their adolescents’ lives will provide further understanding of the role that social work can perform in this field. The rationale for undertaking this study grew out of the literature on adolescents’ studies in addition to the researchers’ interaction with freshmen female students, who are still in the adolescent stage, in the university. The primary purpose of this study was to understand female adolescents’ awareness of healthy parental involvement in their freshmen year in the university life, as well as obstacles that might hinder that healthy involvement. Using semi-structured interview with a purposive sample of the first year female students in the university, the study managed to determine if the type of parental involvement and parental emotional responsiveness between the adolescents and their parents affects the way they interact with their environment, in addition, to determine the obstacles that hamper the communication between adolescents and their parents.

Keywords: adolescents, parental involvement, interaction, university life

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Authors: B. Makhlouf, O. Bouchhida, M. Nibouche, K. Laidi

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A variety of methods for selective harmonics elimination pulse width modulation have been developed, the most frequently used for real-time implementation based on look-up tables method. To address real-time requirements based in modified carrier signal is proposed in the presented work, with a general formulation to real-time harmonics control/elimination in switched inverters. Firstly, the proposed method has been demonstrated for a single value of the modulation index. However, in reality, this parameter is variable as a consequence of the voltage (amplitude) variability. In this context, a simple interpolation method for calculating the modified sine carrier signal is proposed. The method allows a continuous adjustment in both amplitude and frequency of the fundamental. To assess the performance of the proposed method, software simulations and hardware experiments have been carried out in the case of a single-phase inverter. Obtained results are very satisfactory.

Keywords: harmonic elimination, Particle Swarm Optimisation (PSO), polynomial interpolation, pulse width modulation, real-time harmonics control, voltage inverter

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Authors: Sodiq Onawale, Xin Wang

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Integrating renewable energy sources (RES) alongside conventional energy sources (NRES) in the grid has introduced challenges that highlight the need for a detailed analysis of various performance factors. Factors such as active and reactive power losses, voltage deviation, transmission line loading, power factor, fast voltage stability index, and capacity factor require careful evaluation to understand their impact on grid performance. In this study, MATPOWER’s optimization tools are used to model both NRES and a combined NRES + RES setup. The analysis compares the performance of each configuration across these factors. Findings indicate that integrating RES with NRES generally enhances performance across most of the analyzed factors compared to using NRES alone. The insights from this study offer valuable guidance for grid operators and policymakers, aiding in the balanced integration of RES with NRES to optimize smart grid performance and resilience.

Keywords: smart grid, impact analysis, renewable energy integration, FVSI, transmission line loading

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Authors: C. Castro-Egler, A. Durán-Escalante, A. García-González

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This paper presents a method to generate a finite element model of the human auditory inner ear system. The geometric model has been realized using 2D images from a virtual model of temporal bones. A point cloud has been gotten manually from those images to construct a whole mesh with hexahedral elements. The main difference with the predecessor models is the spiral shape of the cochlea with its three scales completely defined: scala tympani, scala media and scala vestibuli; which are separate by basilar membrane and Reissner membrane. To validate this model, numerical simulations have been realised with two models: an isolated inner ear and a whole model of human auditory system. Ideal conditions of displacement are applied over the oval window in the isolated Inner Ear model. The whole model is made up of the outer auditory channel, the tympani, the ossicular chain, and the inner ear. The boundary condition for the whole model is 1Pa over the auditory channel entrance. The numerical simulations by FEM have been done using a harmonic analysis with a frequency range between 100-10.000 Hz with an interval of 100Hz. The following results have been carried out: basilar membrane displacement; the scala media pressure according to the cochlea length and the transfer function of the middle ear normalized with the pressure in the tympanic membrane. The basilar membrane displacements and the pressure in the scala media make it possible to validate the response in frequency of the basilar membrane.

Keywords: finite elements method, human auditory system model, numerical analysis, 3D modelling cochlea

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Authors: Ashfaq Khan, Aftab Khan, Mushtaq Khan, Sarem Sattar, Mohammad A Sheikh, Lin Li

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Chip removal processes are one of key processes of the manufacturing industry where chip removal is conducted by tool inserts of exceptionally hard materials. Tungsten carbide has been extensively used as tool insert for machining processes involving chip removal processes. These hard materials are generally fabricated by single step sintering process as further modification after fabrication in these materials cannot be done easily. Advances in tool surface modification have revealed that advantages such as improved tribological properties and extended tool life can be harnessed from the same tool by texturing the tool rake surface. Moreover, it has been observed that the shape and location of the texture also influences the behavior. Although texturing offers plentiful advantages the challenge lies in the generation of textures on the tool surface. Extremely hard material such as diamond is required to process tungsten carbide. Laser is unique processing tool that does not have a physical contact with the material and thus does not wear. In this research the potential of utilizing laser for texturing of tungsten carbide to develop custom features would be studied. A parametric study of texturing of Tungsten Carbide with a femtosecond laser would be conducted to investigate the process parameters and establish the feasible processing window. The effect of fluence, scan speed and number of repetition would be viewed in detail. Moreover, the mechanism for the generation of features would also be reviewed.

Keywords: laser, texturing, femtosecond, tungsten carbide

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Authors: Hasan Keshavarzian, Tayebeh Nesari

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Bolted rail joint is one of the most vulnerable areas in railway track. A comprehensive approach was developed for studying the reliability of fatigue crack initiation of railroad bolt hole under random axle loads and random material properties. The operation condition was also considered as stochastic variables. In order to obtain the comprehensive probability model of fatigue crack initiation life prediction in railroad bolt hole, we used FEM, response surface method (RSM), and reliability analysis. Combined energy-density based and critical plane based fatigue concept is used for the fatigue crack prediction. The dynamic loads were calculated according to the axle load, speed, and track properties. The results show that axle load is most sensitive parameter compared to Poisson’s ratio in fatigue crack initiation life. Also, the reliability index decreases slowly due to high cycle fatigue regime in this area.

Keywords: rail-wheel tribology, rolling contact mechanic, finite element modeling, reliability analysis

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Authors: Afrah E. Mohammed, Mudawi M. Nour

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Environmentally friendly green synthesis of nanomaterial has a very significant part in nanotechnology. In the present research, the synthesis of silver nanoparticles (AgNPs) was established by treating silver ions with the aqueous extract of Calligonum comosum green shoots at room temperature. AgNPs formation was firstly detected by the colour change of mixed extract (plant extract and AgNO3). Further characterization was done by ultraviolet (UV)-Vis spectrophotometer, transmission electron microscopy (TEM), scanning electron microscopy (SEM), zeta potential and fourier transform infrared spectroscopy (FTIR). The peak values for UV-VIS- spectroscopy were in the range of 440 nm, TEM micrograph showed a spherical shape for the particles and zeta potential showed the formation of negative charged nanoparticles with an average size of about 105.8 nm. 1635.41 and 3249.83 cm−1 are the peaks detected from the FTIR analysis. In this study, biosynthesized silver nanoparticles mediated by C. comosum were tested for their antimycotic activity using a well diffusion method against fungal species; Aspergillus flavus, Penicillium sp, Fusarium oxysporum. Our findings indicated that biosynthesized AgNPs showed an efficient antimycotic activity against tested species. The antimycotic action of AgNPs varied according to different fungal species. Results confirmed the ability of C. comosum green shoot extract to act as an reducing and stabilizing agent during the synthesis of AgNPs.

Keywords: AGNPS, zeta potential, TEM, SEM

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Authors: Ahmad Abubakar Sadiq, Nwohu Ndubuka Mark, Jacob Tsado, Ahmad Adam Asharaf, Agbachi E. Okenna, Enesi E. Yahaya, Ambafi James Garba

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Transmission system performance analysis is vital to proper planning and operations of power systems in the presence of deregulation. Key performance indicators (KPIs) are often used as measure of degree of performance. This paper gives a novel method to determine the transmission efficiency by evaluating the ratio of real power losses incurred from a specified transfer direction. Available Transmission Transfer Efficiency (ATTE) expresses the percentage of real power received resulting from inter-area available power transfer. The Tie line (Rated system path) performance is seen to differ from system wide (Network response) performance and ATTE values obtained are transfer direction specific. The required sending end quantities with specified receiving end ATC and the receiving end power circle diagram are obtained for the tie line analysis. The amount of real power loss load relative to the available transfer capability gives a measure of the transmission grid efficiency.

Keywords: performance, transmission system, real power efficiency, available transfer capability

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Authors: M. Khaled Abduesslam, Mohammed Ali, Basher H. Alsdai, Muhammad Nizam Inayati

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This paper presents the voltage problem location classification using performance of Least Squares Support Vector Machine (LS-SVM) and Learning Vector Quantization (LVQ) in electrical power system for proper voltage problem location implemented by IEEE 39 bus New-England. The data was collected from the time domain simulation by using Power System Analysis Toolbox (PSAT). Outputs from simulation data such as voltage, phase angle, real power and reactive power were taken as input to estimate voltage stability at particular buses based on Power Transfer Stability Index (PTSI).The simulation data was carried out on the IEEE 39 bus test system by considering load bus increased on the system. To verify of the proposed LS-SVM its performance was compared to Learning Vector Quantization (LVQ). The results showed that LS-SVM is faster and better as compared to LVQ. The results also demonstrated that the LS-SVM was estimated by 0% misclassification whereas LVQ had 7.69% misclassification.

Keywords: IEEE 39 bus, least squares support vector machine, learning vector quantization, voltage collapse

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Authors: Ana Lucia Mosquera Rosado

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Media is believed to be the reflection of Peruvian society. However, the context in which media content is generated not always respond to an accurate representation of its cultural diversity, since many of the contents portray images of cultural minorities (indigenous and Afro-Peruvian) that contribute to the reproduction of negative stereotypes, having an impact on society. The current research paper aims to discuss the use of parody as a way of representing Afro-Peruvian population in the national television, through the reproduction of negative stereotypes and the construction of the black body, specifically relating the analysis to El Negro Mama, a very popular character in Peruvian television thought to be a portrait of the Afro-Peruvian men. In order to analyze these representations, the research will use the theory of simulation and simulacra, explained by James Baudrillard to understand the replacement of reality as a consequence of both of these concepts. This research paper will also focus on the social reaction to the existence of this character, in order to construct a hypothesis based on the theory of cultural hegemony, conceived by Jackson Lears as a legitimized group of patterns and behaviors that shape social interaction. This theoretical framework will be used to explain the popularity of this character among Peruvian society and the reactions caused by the controversy generated by the demands of civil society to remove the character from national television.

Keywords: media representation, media, race and ethnicity, racist discourse, afro-descendants in the media

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Authors: M. N. Naong

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Empirical findings of the impact of training on employee motivation and job satisfaction are reported. One of the major debilitating effects of the legacy of apartheid is a high level of illiteracy in the South African population. Encouraging the corporate sector through levies to promote skills development seems to have been received with mixed feelings. In this regard, the impact of training on the motivation level and job satisfaction of randomly sampled employees of five companies in two South African provinces is reported on. A longitudinal study, with a pre- and post-quasi experimental research design, was adopted to achieve the goal of the study - using a Job Description Index (JDI) measuring instrument to collect data from the respondents. There was a significant correlation between job satisfaction and effectiveness of training transfer - i.e. those employees who received more training were more motivated than those who received less training or no training at all. It is concluded that managers need to appreciate and ensure that the effectiveness of skills transfer is a critical determinant, that must illuminate the underlying challenges of achieving bottom-line targets.

Keywords: employee motivation, skills transfer, moderating effect, job satisfaction, lower-level employees

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Authors: Yu-Da Chen, Chia-Chun Wu

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The relationship between antecedent soil moisture content and soil erosion is a complicated phenomenon. Some studies confirm the effect of antecedent soil moisture content on soil erosion, but some deny it. Therefore, the objective of this study is to clarify such contradictions through field experiments. This study conducted two-year field observations of soil losses from natural rainfall events on runoff plots with a length of 10 meters, width of 3 meters, and uniform slope of 9%. Volumetric soil moisture sensors were used to log the soil moisture changes for each rainfall event. A total of 49 effective events were monitored. Results of this study show that antecedent soil moisture content promotes the generation of surface runoff, especially for rainfall events with short duration or lower magnitudes. A positive correlation was found between antecedent soil moisture content and soil loss per unit Rainfall-Runoff Erosivity Index, which indicated that soil with high moisture content is more susceptible to detachment. Once the rainfall duration exceeds 10 hours, the impact from the rainfall duration to soil erosion overwrites, and the effect of antecedent soil moisture is almost negligible.

Keywords: antecedent soil moisture content, soil loss, runoff coefficient, rainfall-runoff erosivity

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Authors: Erwin Stolz, Hannes Mayerl, Anja Waxenegger, Wolfgang Freidl

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Research has often found poverty associated with adverse health outcomes, but it is unclear which (interplay of) mechanisms actually translate low economic resources into poor physical health. The goal of this study was to assess the impact of educational, material, psychosocial and behavioural factors in explaining the poverty-health association in old age. We analysed 28,360 observations from 11,390 community-dwelling respondents (65+) from the Survey of Health, Ageing and Retirement in Europe (SHARE, 2004-2013, 10 countries). We used multilevel growth curve models to assess the impact of combined income- and asset poverty risk on old age frailty index levels and trajectories. In total, 61.8% of the variation of poverty risk on frailty levels could be explained by direct and indirect effects, thereby highlighting the role of material and particularly psychosocial factors, such as perceived control and social isolation. We suggest strengthening social policy and public health efforts in order to fight poverty and its deleterious effects from early age on and to broaden the scope of interventions with regard to psychosocial factors.

Keywords: frailty, health inequality, old age, poverty

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Authors: S. Forughi, A. De Zoysa, S. Bhati

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The present study focuses on the environmental performance of the companies in the electricity-producing sector and its relationship with their financial performance. We will review the major studies that examined the relationship between the environmental and financial performance of firms in various industries. While the classical economic debates consider the environmental friendly activities costly and harmful to a firm’s profitability, it is claimed that firms will be rewarded with higher profitability in long run through the investments in environmental friendly activities. In this context, prior studies have examined the relationship between the environmental and financial performance of firms operating in different industry sectors. Our study will employ an environmental indicator to increase the accuracy of the results and be employed as an independent variable in our developed econometric model to evaluate the impact of the financial performance of the firms on their environmental friendly activities in the context of companies operating in the Australian electricity-producing sector. As a result, we expect our methodology to contribute to the literature and the findings of the study will help us to provide recommendations and policy implications to the electricity producers.

Keywords: Australian electricity sector, efficiency measurement, environmental-financial performance interaction, environmental index

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Authors: Amar Partap Singh Pharwaha, Balkrishan Jindal

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In this paper, a new method is developed for hiding image in a digital image with multilayer security. In the proposed method, the secret image is encrypted in the first instance using a flexible matrix based symmetric key to add first layer of security. Then another layer of security is added to the secret data by encrypting the ciphered data using Pythagorean Theorem method. The ciphered data bits (4 bits) produced after double encryption are then embedded within digital image in the spatial domain using Least Significant Bits (LSBs) substitution. To improve the image quality of the stego-image, an improved form of pixel adjustment process is proposed. To evaluate the effectiveness of the proposed method, image quality metrics including Peak Signal-to-Noise Ratio (PSNR), Mean Square Error (MSE), entropy, correlation, mean value and Universal Image Quality Index (UIQI) are measured. It has been found experimentally that the proposed method provides higher security as well as robustness. In fact, the results of this study are quite promising.

Keywords: Pythagorean theorem, pixel adjustment, ciphered data, image hiding, least significant bit, flexible matrix

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Authors: Ahmed Ramadhan Al-Obaidi, Jassim Alhamid

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In this investigation, the flow pattern, characteristics of thermal-hydraulic, and improvement of heat transfer performance are evaluated using a numerical technique in three dimensions corrugated pipe heat exchanger. The modification was made under different corrugated pipe geometrical parameters, including corrugated ring angle (CRA), distance between corrugated ring (DBCR), and corrugated diameter (CD), the range of Re number from 2000 to 12000. The numerical results are validated with available experimental data. The numerical outcomes reveal that there is an important change in flow field behaviour and a significant increase in friction factor and improvement in heat transfer performance owing to the use of the corrugated shape in the heat exchanger pipe as compared to the conventional smooth pipe. Using corrugated pipe with different configurations makes the flow more turbulence, flow separation, boundary layer distribution, flow mixing, and that leads to augmenting the performance of heat transfer. Moreover, the value of pressure drop, and the Nusselt number increases as the corrugated pipe geometrical parameters increase. Furthermore, the corrugation configuration shapes have an important influence on the thermal evaluation performance factor, and the maximum value was more than 1.3. Numerical simulation can be performed to predict the various geometrical configurations effects on fluid flow, thermal performance, and heat transfer enhancement.

Keywords: corrugated ring angle, corrugated diameter, Nusselt number, heat transfer

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Authors: A. Bogdanovic, M. Vitanova, J. Bojadjieva, Z. Rakicevic, V. Sesov, K. Edip, N. Naumovski, F. Manojlovski, A.Popovska, A. Shoklarovski, T. Kitanovski, D. Ivanovski, I. Markovski, D. Filipovski

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The conditions of existing structures change in the course of time and can hardly be characterized particularly if a bridge has long been in function and there is no design documentation related to it. To define the real conditions of a structure, detailed static and dynamic analysis of the structure has to be carried out and its modal parameters have to be defined accurately. Modal analysis enables a quite accurate identification of the natural frequencies and mode shapes. Presented in this paper are the results from the performed detailed analyses of a steel truss bridge that has been in use for more than 7 decades by the military services of R.N. Macedonia and for which there is no documentation at all. Static and dynamic investigations and ambient vibration measurements were performed. The acquired data were used to identify the mode shapes that were used for comparison with the numerical model. Dynamic tests were performed to define the bridge behaviour and the damping index. Finally, based on all the conducted detailed analyses and investigations, conclusions on the conditions of the bridge structure were drawn.

Keywords: ambient vibrations, dynamic identification, in-situ measurement, steel truss bridge

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Authors: J. O. Akinyele, R. W. Salim, K. O. Oikelome, O. T. Olateju

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Rice Husk (RH) is the major byproduct in the processing of paddy rice. The management of this waste has become a big challenge to some of the rice producers, some of these wastes are left in open dumps while some are burn in the open space, and these two actions have been contributing to environmental pollution. This study evaluates an alternative waste management of this agricultural product for use as a civil engineering material. The RH was burn in a controlled environment to form Rice Husk Ash (RHA). The RHA was mix with lateritic clay at 0, 2, 4, 6, 8, and 10% proportion by weight. Chemical test was conducted on the open burn and controlled burn RHA with the lateritic clay. Physical test such as particle size distribution, Atterberg limits test, and density test were carried out on the mix material. The chemical composition obtained for the RHA showed that the total percentage compositions of Fe2O3, SiO2 and Al2O3 were found to be above 70% (class “F” pozzolan) which qualifies it as a very good pozzolan. The coefficient of uniformity (Cu) was 8 and coefficient of curvature (Cc) was 2 for the soil sample. The Plasticity Index (PI) for the 0, 2, 4, 6, 8. 10% was 21.0, 18.8, 16.7, 14.4, 12.4 and 10.7 respectively. The work concluded that RHA can be effectively used in hydraulic barriers and as a stabilizing agent in soil stabilization.

Keywords: rice husk ash, pozzolans, paddy rice, lateritic clay

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Authors: Janki Shankar, Shu Ping Chen

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Background: New immigrants are one of most vulnerable sections of the Canadian society. Unable to gain entry into Canada’s strictly regulated professions and trades, several skilled and qualified new immigrants take up precarious jobs without adequate occupational health and safety training, thereby increasing their risk of sustaining occupational injury and illness compared to Canadian born workers. Access to timely and appropriate support is critical for injured new immigrant workers who face additional challenges compared to Canadian born workers in accessing information and support post-injury. The purpose of our study was to explore the post-injury experiences and support needs of new immigrant workers who have sustained work-related injuries. Methods: Using an interpretive research approach and semi structured face to face qualitative interviews, 27 new immigrant workers from a range of industries operating in two cities in a province in Canada were interviewed. All had sustained work-related injuries and reported these to their work supervisors. A constant comparative approach was used to identify key themes across the worker experiences. Results: Findings reveal several factors that can shape the experiences of new immigrant workers and influence their return-to-work outcomes. Conclusion: Based on the insights of study participants, policies, practices, and potential interventions informed by their needs and preferences are proposed that can improve return to work outcomes for these workers.

Keywords: new immigrant workers, post-injury experiences, return to work outcomes, qualified

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Authors: Jutamas Wisansing, Thanakarn Vongvisitsin, Udom Hongchatikul

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Designated Areas for Sustainable Tourism Administration (DASTA) is a public organization, dedicating to sustainable tourism development in 6 designated areas in Thailand. This paper provides rich reflections from a decade of DASTA, formulating an advanced model to deepen our understanding of 2 key intertwining issues; 1) what are the new landscapes of actors for community based tourism and 2) who are the benefactors and beneficiaries of tourism development within the community? An action research approach was used, enabling the process and evidence-based cases to be better captured. The aim is to build theoretical foundation through 13 communities/cases, which have engaged in community based tourism pilot projects. Drawing from emic and qualitative research, specific and contextual phenomenon provides succinct patterns of ‘Community Benefitting through Tourism (CbtT)’ model. The re-definition of the 2 key issues helps shape the interlinking of actors; practicalities of inclusive tourism and inter-sectoral framework and its value chain will also be set forth. In tourism sector, community members could be active primarily on the supply side as employees, entrepreneurs and local heritage experts. CbtT when well defined stimulates the entire value chain of local economy while promoting social innovation through positive dialogue with wider actors. Collaboration with a new set of actors who are from the tourism-related businesses and non-tourism related businesses create better impacts on mutual benefits.

Keywords: community based tourism, community benefitting through tourism -CbtT DASTA model, sustainable tourism in thailand, value chain and inclusive business

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Authors: Joo-min Kim, Gi-wook Shin, Tae-ho Chung, Chul Park, Seong-hyun Kim, Namjung Kim

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Mealworm (Tenebrio molitor) was evaluated to investigate the effect of partial or total replacement of fish meal in diets for olive flounder, Paralichthys olivaceus. Experimental groups of fish with average initial body weight (287.5 ± 7.24 g) were fed each with 4 isonitrogeneous (52% crude protein) diets formulated to include 0, 7, 17 and 27% (diets 1 to 4, respectively) of fish meal substituted with mealworm. After six weeks of feeding trials, fish fed with diet 3 revealed the highest values for live weight gain(42.10), specific growth rates (0.445 ± 0.089) as well as better feed conversion ratio (12.08) compared to the other group with statistically significant manner (p<0.05). Hepatosomatic index was showed no significant difference in diet 3 compared to the control group. An increase in weight gain and other growth associated parameters was observed in diet 3. These results clearly indicate that 17% of fish meal protein in bastard halibut diet can be replaced by mealworm not only without any adverse effect but also the effect of promoting growth performance.

Keywords: mealworm, olive flounder, Paralichthys olivaceus, Tenebrio molitor

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Authors: Lakshmana Ravi Raj Gali, K. Sridhar Reddy, M. Amaranatha Reddy

Abstract:

Load transfer between adjacent slabs of the jointed plain concrete pavement (JPCP) system is inevitable for long-lasting performance. Dowel bars are generally used to ensure sufficient degree of load transfer, in addition to the load transferred by aggregate interlock mechanism at the joints. Joint efficiency is the measure of joint quality, a major concern and therefore the dowel bar system should be designed and constructed well. The interaction between dowel bars and concrete that includes various parameters of dowel bar and concrete will explain the degree of joint efficiency. The present study focuses on the methodology of selecting contact stiffness, which quantifies dowel-concrete interaction. In addition, a parametric study which focuses on the effect of dowel diameter, dowel shape, the spacing between dowel bars, joint opening, the thickness of the slab, the elastic modulus of concrete, and concrete cover on contact stiffness was also performed. The results indicated that the thickness of the slab is most critical among various parameters to explain the joint efficiency. Further displacement equivalency method was proposed to find out the contact stiffness. The proposed methodology was validated with the available field surface deflection data collected by falling weight deflectometer (FWD).

Keywords: contact stiffness, displacement equivalency method, Dowel-concrete interaction, joint behavior, 3D numerical simulation

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Authors: Zakheleni P. Dube, Phatu W. Mashela

Abstract:

Minimum inhibition concentration (MIC) is the lowest concentration of a chemical that brings about significant inhibition of target organism. The conventional method for establishing the MIC for phytonematicides is tedious. The objective of this study was to use the Curve-fitting Allelochemical Response Data (CARD) to determine the MIC for pure cucurbitacin A on Meloidogyne incognita second-stage juveniles (J2) hatch, immobility and mortality. Meloidogyne incognita eggs and freshly hatched J2 were separately exposed to a series of pure cucurbitacin A concentrations of 0.00, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75, 2.00, 2.25 and 2.50 μg.mL⁻¹for 12, 24, 48 and 72 h in an incubator set at 25 ± 2°C. Meloidogyne incognita J2 hatch, immobility and mortality counts were determined using a stereomicroscope and the significant means were subjected to the CARD model. The model exhibited density-dependent growth (DDG) patterns of J2 hatch, immobility and mortality to increasing concentrations of cucurbitacin A. The average MIC for cucurbitacin A on M. incognita J2 hatch, immobility and mortality were 2.2, 0.58 and 0.63 µg.mL⁻¹, respectively. Meloidogyne incognita J2 hatch had the highest average MIC value followed by mortality and immobility had the least. In conclusion, the CARD model was able to generate MIC for cucurbitacin A, hence it could serve as a valuable tool in the chemical-nematode bioassay studies.

Keywords: inhibition concentration, phytonematicide, sensitivity index, threshold stimulation, triterpenoids.

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Authors: Debadi Chakraborty, John E. Sader

Abstract:

Nanomechanical devices have emerged as a versatile platform for a host of applications due to their extreme sensitivity to environmental conditions. For example, mass measurements with sensitivity at the atomic level have recently been demonstrated. Ultrafast laser spectroscopy coherently excite the vibrational modes of metal nanoparticles and permits precise measurement of the vibration characteristics as a function of nanoparticle shape, size and surrounding environment. This study reports that the vibration of metal nanoparticles in simple liquids, like water and glycerol are not described by conventional fluid mechanics, i.e., Navier Stokes equations. The intrinsic molecular relaxation processes in the surrounding liquid are found to have a profound effect on the fluid-structure interaction of mechanical devices at nanometre scales. Theoretical models have been developed based on the non-Newtonian viscoelastic fluid-structure interaction theory to investigate the vibration of nanoparticles immersed in simple fluids. The utility of this theoretical framework is demonstrated by comparison to measurements on single nanowires and ensembles of metal rods. This study provides a rigorous foundation for the use of metal nanoparticles as ultrasensitive mechanical sensors in fluid and opens a new paradigm for understanding extremely high frequency fluid mechanics, nanoscale sensing technologies, and biophysical processes.

Keywords: fluid-structure interaction, nanoparticle vibration, ultrafast laser spectroscopy, viscoelastic damping

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Authors: Getabalew Derib, Arragaw Alemayehu

Abstract:

Assessing the sustainability of watersheds holds significant importance for regional natural resource management and to achieve sustainable development. This study investigated the sustainability of the Wulo Abiye watershed, central highlands of Ethiopia. The sustainability status of the watershed was evaluated by using 17 indicators representing the economic, social, and environmental dimensions of sustainable development goals (SDGs) based on the local and existing conditions of the watershed. The results indicated that environmental sustainability was at a ’ high’ level, while social and economic sustainability and the aggregate index were at ‘moderate’ levels. The overall level of community participation in the planning and evaluation phases of watershed management was at ’low’ levels. The implementation phase was at ’high’ level. Overall , the sustainability status of watershed management and level of community participation were at ‘moderate’ levels. The study concluded that integrated support is needed to overcome the identified challenges to achieve sustainable development in watersheds.

Keywords: Wulo Abiye watershed, community participation, watershed management, sustainable development

Procedia PDF Downloads 46