Search results for: static allocation

Authors: Kalpana Goel

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Australian social work schools are finding it difficult to find appropriate placements for the increasing number of international students enrolled in their Master of Social Work qualifying (MSWQ) programs. Anecdotally, it has been noticed that fewer social work students are ready to work with older people whose numbers are rising globally. An innovative and unique placement for international students enrolled in the MSWQ at one Australian university was organised in partnership with a community-based service working with older clients to meet two objectives: increasing the number of suitable placements for international students and preparing social work students to work with older people. Creative activities and projects were designed to provide meaningful engagement and experience in working with older people in the community. Students participated in a number of projects that were matched with their interest and capability in a 500-hour placement. The students were asked to complete an online survey after all work for the placement had been completed. The areas of assessment were: self-perceived change in perception towards age and older people, valued field placement experiences including reflective practice, knowledge and skill development, and constraints and challenges experienced in the placement. Findings revealed students’ increased level of confidence in applying social work theory to practice, developing effective communication and interpersonal skills, and use of innovation and creativity in preparing well-being plans with older adults. Challenges and constraints related to their limited English language ability and lack of cultural knowledge of the host society. It was recognised that extra support for these students and more planning in the beginning phase of placement are vital to placement success. Caution in matching students with clients of similar cultural background must be exercised to ensure that there is equity in task allocation and opportunities for wider experiences.

Keywords: field placement, international students, older people, social work

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Authors: Shafiqul Islam, Cordia Chu

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Bangladesh contributes little to global climate change, yet it is one of the countries most vulnerable to climate change. Based on semi-structured in-depth interviews and literature review, focusing public spending distribution process, this paper demonstrates how the processes of political economy- enclosure, exclusion, encroachment, and entrenchment hinder the Climate Change Adaptation (CCA) efforts of Bangladesh Climate Change Trust Fund (BCCTF). Enclosure refers to when CCA projects allocated to less vulnerable areas or expand the roles of influencing actors into the public sphere. Exclusion refers to when CCA projects limit affected people's access to resources or marginalize particular stakeholders in decision-making activities. Encroachment refers to when allocation of CCA projects and selection of location and issues degrade the environmental affect or contribute to other forms of disaster risk. Entrenchment refers to when CCA projects aggravate the disempowerment of common people worsen the concentrations of wealth and income inequality within a community. In the case of Bangladesh, climate change policies implemented under the country’s National Adaptation Program of Action (NAPA) and Bangladesh Climate Change Strategic Action Plan (BCCSAP) have somehow enabled influential-elites to mobilize and distribute resources through bureaucracies. Exclusionary forms of fund distribution of CCA exist at both the national and local scales. CCA related allocations have encroached through the low land areas development project without consulting local needs. Most severely, CCA related unequal allocations have entrenched social class trapping the backward communities vulnerable to climate related disasters. Planners and practitioners of BCCTF need to take necessary steps to eliminate the potential risks from the processes of enclosure, exclusion, encroachment, and entrenchment happens in project fund allocations.

Keywords: Bangladesh, climate change adaptation, political economy, public fund distribution

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Authors: Showkat Ahmad Bhat, M. S. Bhatt

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The study evaluates the ex-post impact of institutional credit on agricultural output. It first examines the key factors that influence the accessibility of institutional credit by farm households. For quantitative analysis both program participant and non-participant respondents were drawn and cross-sectional survey data were collected from 412 households in Pulwama District of Jammu & Kashmir (India). Propensity Score Matching Method was employed to analyze the impact of the institutional credit on agricultural output. Results show that institutional credit has a positive and significant impact on the agricultural output measured in terms of farm income and crop productivity. To estimate the accessibility of credit, an examination of both demand side and supply side factors were carried out. The demand for credit was measured with respect to respondents who applied for credit. Supply side credit allocation measured in terms of the proportion of ‘credit amount’ farmers obtained. Logit and Two-limit Tobit Regression Models were used to investigate the determinants that influence the accessibility of formal credit for Demand for and supply of credit respectively. The estimated results suggested that the demand for credit is positively and significantly affected by the factors such as: age of the household head, formal education, membership, cash crop grown, farm size and saving account. All the variables were found significantly increasing the household’s likelihood to demand for and supply of credit from banks. However, the impact of these factors varies considerably across the credit markets. Factors which were found negatively and significantly influencing the accessibility of credit were: ‘square of the age’, household assets and rate of interest. The credit constraints analysis suggested that square of the age; household assets and rate of interest were the three most important factors that increased the probability of being constrained. The study finally discusses these results in detail and draws some recommendations.

Keywords: institutional credit, agriculture, propensity score matching logit model, Tobit model

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Authors: Zintle Sikhunyana

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Management of public finance in many countries such as South Africa is affected by political decisions and by policies around fiscal decentralization amongst the government spheres. Economic success is said to be determined by efficient management of public finance and by the policies or strategies that are implemented to support efficient public finance management. Policymakers focus on pay attention to how economic policies have been implemented and how they are directed into ensuring stable development. This will allow policymakers to address economic challenges through the usage of fiscal policy parameters that are linked to the achieved rate of economic growth and development. Efficient public finance management reduces the likelihood of corruption and corruption is said to have negative effects on economic growth and development. Corruption in public finance refers to an act of using funds for personal benefits. To achieve macroeconomic objectives, governments make use of government expenditure and government expenditure is financed through tax revenue. The main aim of this paper is to investigate the potential impact of public finance management on economic growth and development in South Africa. The secondary data obtained from the South African Reserve Bank (SARB) and World Bank for 1980- 2020 has been utilized to achieve the research objectives. To test the impact of public finance management on economic growth and development, the study will use Seeming Unrelated Regression Equation (SURE) Modelling that allows researchers to model multiple equations with interdependent variables. The advantages of using SUR are that it efficiently allows estimation of relationships between variables by combining information on different equations and SUR test restrictions that involve parameters in different equations. The findings have shown that there is a positive relationship between efficient public finance management and economic growth/development. The findings also show that efficient public finance management has an indirect positive impact on economic growth and development. Corruption has a negative impact on economic growth and development. It results in an efficient allocation of government resources and thereby improves economic growth and development. The study recommends that governments who aim to stimulate economic growth and development should target and strengthen public finance management policies or strategies.

Keywords: corruption, economic growth, economic development, public finance management, fiscal decentralization

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Authors: Yanqun Li, Hong Geng

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The rapid urbanization process taking big cities as the main body leads to the unequal configuration of urban and rural areas in the aspects of land supply, industrial division of labor, service supply and space allocation, and induces the shrinking characterization of service energy, industrial system and population vitality in small towns. As an important spatial unit in the spectrum of urbanization that serves, connects and couples urban and rural areas, the shrinking phenomenon faced by small towns has an important influence on the healthy development of urbanization. Based on the census of small towns in Wuhan metropolitan area, we have found that the shrinking of small towns is a passive contraction of elastic tension under the squeeze in cities. Once affected by the external forces such as policy regulation, planning guidance, and population return, small towns will achieve expansion and growth. Based on the theory of complex adaptive systems, this paper comprehensively constructs the development index evaluation system of small towns from five aspects of population, economy, space, society and ecology, measures the shrinking level of small towns, further analyzes the shrinking characteristics of small towns, and identifies whether the shrinking is elastic or not. And then this paper measures the resilience ability index of small town contract from the above-mentioned five aspects. Finally, this paper proposes an adaptive mechanism of urban-rural interaction evolution under fine division of labor to response the passive shrinking in small towns of Wuhan. Based on the above, the paper creatively puts forward the planning response measures of the small towns on the aspects of spatial layout, function orientation and service support, which can provide reference for other regions.

Keywords: complex adaptive systems, resiliency shrinking, adaptation mechanism, planning response

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Authors: Abdelhammid Chibane

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Often, for architectural reasons or designs, several buildings have a non-uniform profile in elevation. Depending on the configuration of the construction and the arrangements structural elements, the non-uniform profile in elevation (the recess) is considered concept of a combination of non-uniform distributions of strength, stiffness, weight and geometry along the height of irregular structures. Therefore, this type of configuration can induce irregular distribution load causing a serious concentration stresses at the discontinuity. This therefore requires a serious behavioral treatment buildings in an earthquake. If appropriate measures are not taken into account, structural irregularity may become a major source of damage during earthquakesEarth. In the past, several research investigations have identified differences in dynamic response of irregular and regular porches. Among the most notable differences are the increments of displacements and ductility applications in floors located above the level of the shoulder and an increase in the contribution of the higher modes cisaillement1 efforts, ..., 10. The para -ssismiques codes recommend the methods of analysis Dynamic (or modal history) to establish the forces of calculation instead of the static method equivalent, which is basically applicable only to regular structures without major discontinuities in the mass, rigidity and strength along the height 11, 12 .To investigate the effects of irregular profiles on the structures, the main objective of this study was the assessment of the inelastic response, in terms of applications of ductility four types of non-uniform multi-stage structures subjected to relatively severe earthquakes. In the This study, only the parallel responses are analyzed setback.

Keywords: buildings, concentration stresses, ductility, ductility, designs, irregular structures

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Authors: Mallikarjunachari Gangapuram

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The design of stimuli-responsive hydrogel nanocomposite thin films is gaining significant attention in these days due to its wide variety of applications. Soft microrobots, drug delivery, biosensors, regenerative medicine, bacterial adhesion, energy storage and wound dressing are few advanced applications in different fields. In this research work, the nanomechanical properties of composite thin films of 20 microns were tuned by applying homogeneous external DC, and AC magnetic fields of magnitudes 0.05 T and 0.1 T. Polyvinyl alcohol (PVA) used as a matrix material and elliptical hematite nanoparticles (ratio of the length of the major axis to the length of the minor axis is 140.59 ± 1.072 nm/52.84 ± 1.072 nm) used as filler materials to prepare the nanocomposite thin films. Both quasi-static nanoindentation, Nano Dynamic Mechanical Analysis (Nano-DMA) tests were performed to characterize the viscoelastic properties of PVA, PVA+Hematite (0.1% wt, 2% wt and 4% wt) nanocomposites. Different properties such as storage modulus, loss modulus, hardness, and Er/H were carefully analyzed. The increase in storage modulus, hardness, Er/H and a decrease in loss modulus were observed with increasing concentration and DC magnetic field followed by AC magnetic field. Contact angle and ATR-FTIR experiments were conducted to understand the molecular mechanisms such as hydrogen bond formation, crosslinking density, and particle-particle interactions. This systematic study is helpful in design and modeling of magnetic responsive hydrogel nanocomposite thin films for biomedical applications.

Keywords: hematite, hydrogel, nanoindentation, nano-DMA

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Authors: Mohammad Derakhshani, Saeed Reza Allahkarama, Michael Isakhani-Zakaria, Masoud Samadian, Hojjat Sharifi Rasaey

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In order to investigate the effects of stray current from DC traction systems (subway) on cathodically protected gas pipelines, the subway and the gas network maps in the city of Tehran were superimposed and a comprehensive map was prepared. 213 intersections and about 100150 meters of parallel sections of gas pipelines were found with respect to the railway right of way which was specified for field measurements. The potential measurements data were logged for one hour in each test point. 24-hour potential monitoring was carried out in selected test points as well. Results showed that dynamic stray current from subway on pipeline potential appears as fluctuations in its static potential that is visible in the diagrams during night periods. These fluctuations can cause the pipeline potential to exit the safe zone and lead to corrosion or overprotection. In this study, a maximum potential shift of 100 mv in the pipe-to-soil potential was considered as a criterion for dynamic stray current effective presence. Results showed that a potential fluctuation range between 100 mV to 3 V exists in measured points on pipelines which exceeds the proposed criterion and needs to be investigated. Corrosion rates influenced by stray currents were calculated using coupons. Results showed that coupon linked to the pipeline in one of the locations at region 1 of the city of Tehran has a corrosion rate of 4.2 mpy (with cathodic protection and under influence of stray currents) which is about 1.5 times more than free corrosion rate of 2.6 mpy.

Keywords: stray current, DC traction, subway, buried Pipelines, cathodic protection list

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Authors: Elin Julianti, Marlia Singgih, Masayoshi Arai, Jianyu Lin, Masteria Yunovilsa Putra, Muhammad Azhari, Agnia S. Muharam

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The search for a source of new medicinal compounds with anticancer activity from natural products has become important to resolve the ineffectiveness problem of pancreatic cancer therapy. Fungal marine microorganisms are prolific sources of bioactive natural products. In this present study, the ethyl acetate extract of cultured broth of Trichoderma longibrachiatum marine sponge-derived fungi exhibited selective cytotoxicity against human pancreatic carcinoma PANC-1 cells cultured under glucose-deficient conditions (IC50 = 98,4 µg/mL). The T. longibrachiatum was fermented by the static method at room temperature for 60 days. The culture broth was extracted using ethyl acetate by liquid-liquid extraction method. The liquid-liquid extraction was conducted toward the ethyl extract by using 90% MeOH-H₂O and n-|Hexane as a solvent. The extract of 90% MeOH-H₂O was fractionated by liquid extraction using by C₁₈ reversed-phase vacuum flash chromatography using mixtures of MeOH-H₂O, from 50:50 to 100:0, and 1% TFA MeOH as the eluents to yield six fractions. The fraction 2 (MeOH-H2O, 70:30) and fraction 3 (MeOH-H2O, 80:20) showed moderate cytotoxicity with IC50 value of 119.3 and 274.7 µg/mL, respectively. Fraction 4 (MeOH-H₂O, 90:10) showed the highest cytotoxicity activity with IC₅₀value of < 10 µg/mL. The chemical compounds of the fractions that are responsible for cytotoxic activity are potent for further investigation.

Keywords: cytotoxic activity, trichoderma longibrachiatum, marine-derived fungi, PANC-1 cell line

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Authors: Kuo-Cheng Liu

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In the perceptual image coding, the objective is to shape the coding distortion such that the amplitude of distortion does not exceed the error visibility threshold, or to remove perceptually redundant signals from the image. While most researches focus on color image coding, the perceptual-based quantizer developed for luminance signals are always directly applied to chrominance signals such that the color image compression methods are inefficient. In this paper, the internal generative mechanism is integrated into the design of a color image compression method. The internal generative mechanism working model based on the structure-based spatial masking is used to assess the subjective distortion visibility thresholds that are visually consistent to human eyes better. The estimation method of structure-based distortion visibility thresholds for color components is further presented in a locally adaptive way to design quantization process in the wavelet color image compression scheme. Since the lowest subband coefficient matrix of images in the wavelet domain preserves the local property of images in the spatial domain, the error visibility threshold inherent in each coefficient of the lowest subband for each color component is estimated by using the proposed spatial error visibility threshold assessment. The threshold inherent in each coefficient of other subbands for each color component is then estimated in a local adaptive fashion based on the distortion energy allocation. By considering that the error visibility thresholds are estimated using predicting and reconstructed signals of the color image, the coding scheme incorporated with locally adaptive perceptual color quantizer does not require side information. Experimental results show that the entropies of three color components obtained by using proposed IGM-based color image compression scheme are lower than that obtained by using the existing color image compression method at perceptually lossless visual quality.

Keywords: internal generative mechanism, structure-based spatial masking, visibility threshold, wavelet domain

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Authors: Zhenzhen Xu, Chunfu Shao, Shengyou Wang, Chunjiao Dong

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To improve the satisfaction of residents' travel, this paper analyzes the characteristics and influencing factors of urban residents' travel behavior. First, a Multinominal Logit Model (MNL) model is built to analyze the characteristics of residents' travel behavior, reveal the influence of individual attributes, family attributes and travel characteristics on the choice of travel mode, and identify the significant factors. Then put forward suggestions for policy improvement. Finally, Support Vector Machine (SVM) and Multi-Layer Perceptron (MLP) models are introduced to evaluate the policy effect. This paper selects Futian Street in Futian District, Shenzhen City for investigation and research. The results show that gender, age, education, income, number of cars owned, travel purpose, departure time, journey time, travel distance and times all have a significant influence on residents' choice of travel mode. Based on the above results, two policy improvement suggestions are put forward from reducing public transportation and non-motor vehicle travel time, and the policy effect is evaluated. Before the evaluation, the prediction effect of MNL, SVM and MLP models was evaluated. After parameter optimization, it was found that the prediction accuracy of the three models was 72.80%, 71.42%, and 76.42%, respectively. The MLP model with the highest prediction accuracy was selected to evaluate the effect of policy improvement. The results showed that after the implementation of the policy, the proportion of public transportation in plan 1 and plan 2 increased by 14.04% and 9.86%, respectively, while the proportion of private cars decreased by 3.47% and 2.54%, respectively. The proportion of car trips decreased obviously, while the proportion of public transport trips increased. It can be considered that the measures have a positive effect on promoting green trips and improving the satisfaction of urban residents, and can provide a reference for relevant departments to formulate transportation policies.

Keywords: neural network, travel characteristics analysis, transportation choice, travel sharing rate, traffic resource allocation

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Authors: D. Chronopoulos, I. Antoniadis, V. Spitas, D. Koulocheris, V. Polenta

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A concept of a simple linear oscillator, incorporating a negative stiffness element is demonstrated to exhibit extraordinary damping properties. This oscillator shares the same overall (static) stiffness, the same mass and the same damping element with a reference classical linear SDOF oscillator. However, it differs from the original SDOF oscillator by appropriately redistributing the component spring stiffness elements and by re-allocating the damping element. Despite the fact that the proposed oscillator incorporates a negative stiffness element, it is designed to be both statically and dynamically stable. Once such an oscillator is optimally designed, it is shown to exhibit an extraordinary apparent damping ratio, which is even several orders of magnitude higher than that of the original SDOF system, especially in cases where the original damping of the SDOF system is low. This damping behavior is not a result of a novel additional extraordinary energy dissipation mechanism, but a result of the phase difference between the positive and the negative stiffness elastic forces, which is in turn a consequence of the proper re-distribution of the stiffness and the damper elements. This fact ensures that an adequate level of elastic forces exists throughout the entire frequency range, able to counteract the inertial and the excitation forces. Next, Acoustic or Phononic Meta-materials are considered, in which one atom is replaced by the concept of the above simple linear oscillator. The results indicate that not only the damping of the meta-material verifies and exceeds the one expected from the so-called "meta-damping" behavior, but also that the band gap of the meta-material can be significantly increased.

Keywords: wave propagation, periodic structures, wave damping, mechanical engineering

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Authors: Youssouf Benmeriem

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Shear strength of sandy soils has been considered as the important parameter to study the stability of different civil engineering structures when subjected to monotonic, cyclic and earthquake loading conditions. The proposed research investigated the effect of grading characteristics on the shear strength and mechanical behavior of granular classes of sands mixed with silt in loose and dense states (Dr = 15% and 90%). The laboratory investigation aimed at understanding the extent or degree at which shear strength of sand-silt mixture soil is affected by its gradation under static loading conditions. For the purpose of clarifying and evaluating the shear strength characteristics of sandy soils, a series of Casagrande shear box tests were carried out on different reconstituted samples of sand-silt mixtures with various gradations. The soil samples were tested under different normal stresses (100, 200 and 300 kPa). The results from this laboratory investigation were used to develop insight into the shear strength response of sand and sand-silt mixtures under monotonic loading conditions. The analysis of the obtained data revealed that the grading characteristics (D10, D50, Cu, ESR, and MGSR) have significant influence on the shear strength response. It was found that shear strength can be correlated to the grading characteristics for the sand-silt mixture. The effective size ratio (ESR) and mean grain size ratio (MGSR) appear as pertinent parameters to predict the shear strength response of the sand-silt mixtures for soil gradation under study.

Keywords: grading characteristics, granular classes of sands, mechanical behavior, sand-silt, shear strength

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Authors: Hyun Seop Uhm, Yong Ho Choi, Ji Eun Kim, Young Hoon Lee

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Weapon-target assignment (WTA) is a problem that assigns available launchers to appropriate targets in order to defend assets. Various algorithms for WTA have been developed over past years for both in the static and dynamic environment (denoted by SWTA and DWTA respectively). Due to the problem requirement to be solved in a relevant computational time, WTA has suffered from the solution efficiency. As a result, SWTA and DWTA problems have been solved in the limited situation of the battlefield. In this paper, the general situation under continuous time is considered by Time based Weapon Target Assignment (TWTA) problem. TWTA are studied using the mixed integer programming model, and three heuristic algorithms; decomposed opt-opt, decomposed opt-greedy, and greedy algorithms are suggested. Although the TWTA optimization model works inefficiently when it is characterized by a large size, the decomposed opt-opt algorithm based on the linearization and decomposition method extracted efficient solutions in a reasonable computation time. Because the computation time of the scheduling part is too long to solve by the optimization model, several algorithms based on greedy is proposed. The models show lower performance value than that of the decomposed opt-opt algorithm, but very short time is needed to compute. Hence, this paper proposes an improved method by applying decomposition to TWTA, and more practical and effectual methods can be developed for using TWTA on the battlefield.

Keywords: air and missile defense, weapon target assignment, mixed integer programming, piecewise linearization, decomposition algorithm, military operations research

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Authors: Majid Haghshenas, James Wilson, Ranganathan Kumar

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In this study, an Algebraic Coupled Level Set-Volume of Fluid (A-CLSVOF) method with capillary pressure treatment is proposed for the modeling of two-phase capillary flows. The Volume of Fluid (VOF) method is utilized to incorporate one-way coupling with the Level Set (LS) function in order to further improve the accuracy of the interface curvature calculation and resulting surface tension force. The capillary pressure is determined and treated independently of the hydrodynamic pressure in the momentum balance in order to maintain consistency between cell centered and interpolated values, resulting in a reduction in parasitic currents. In this method, both VOF and LS functions are transported where the new volume fraction determines the interface seed position used to reinitialize the LS field. The Hamilton-Godunov function is used with a second order (in space and time) discretization scheme to produce a signed distance function. The performance of the current methodology has been tested against some common test cases in order to assess the reduction in non-physical velocities and improvements in the interfacial pressure jump. The cases of a static drop, non-linear Rayleigh-Taylor instability and finally a droplets impact on a liquid pool were simulated to compare the performance of the present method to other well-known methods in the area of parasitic current reduction, interface location evolution and overall agreement with experimental results.

Keywords: two-phase flow, capillary flow, surface tension force, coupled LS with VOF

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Authors: Yong Jae Yu, Jae-Yeol Cho

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In the design of structural concrete for impact loading, design or model codes often employ a dynamic increase factor (DIF) to impose dynamic effect on static response. Dynamic increase factors that are obtained from laboratory material test results and that are commonly given as a function of strain rate only are quite different from each other depending on the design concept of design codes like ACI 349M-06, fib Model Code 2010 and ACI 370R-14. Because the dynamic increase factors currently adopted in the codes are too simple and limited to consider a variety of strength of materials, their application in practical design is questionable. In this study, the dynamic increase factors used in the three codes were validated through the finite element analysis of reinforced concrete slab elements which were tested and reported by other researcher. The test was intended to simulate a wall element of the containment building in nuclear power plants that is assumed to be subject to impact scenario that the Pentagon experienced on September 11, 2001. The finite element analysis was performed using the ABAQAUS 6.10 and the plasticity models were employed for the concrete, reinforcement. The dynamic increase factors given in the three codes were applied to the stress-strain curves of the materials. To estimate the dynamic increase factors, strain rate was adopted as a parameter. Comparison of the test and analysis was done with regard to perforation depth, maximum deflection, and surface crack area of the slab. Consequently, it was found that DIF has so great an effect on the behavior of the reinforced concrete structures that selection of DIF should be very careful. The result implies that DIF should be provided in design codes in more delicate format considering various influence factors.

Keywords: impact, strain rate, DIF, slab elements

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Authors: Geng Xiangren, Liu Lei, Gui Ye-Wei, Tang Wei, Wang An-ling

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The malfunction of thermal protection system (TPS) caused by aerodynamic heating is a latent trouble to aircraft structure safety. Accurately predicting the structure temperature field is quite important for the TPS design of hypersonic vehicle. Since Thornton’s work in 1988, the coupled method of aerodynamic heating and heat transfer has developed rapidly. However, little attention has been paid to the influence of structural deformation on aerodynamic heating and structural temperature field. In the flight, especially the long-endurance flight, the structural deformation, caused by the aerodynamic heating and temperature rise, has a direct impact on the aerodynamic heating and structural temperature field. Thus, the coupled interaction cannot be neglected. In this paper, based on the method of static aero-thermo-elasticity, considering the influence of aero-thermo-elasticity deformation, the aerodynamic heating and heat transfer coupled results of hypersonic vehicle wing model were calculated. The results show that, for the low-curvature region, such as fuselage or center-section wing, structure deformation has little effect on temperature field. However, for the stagnation region with high curvature, the coupled effect is not negligible. Thus, it is quite important for the structure temperature prediction to take into account the effect of elastic deformation. This work has laid a solid foundation for improving the prediction accuracy of the temperature distribution of aircraft structures and the evaluation capacity of structural performance.

Keywords: aerothermoelasticity, elastic deformation, structural temperature, multi-field coupling

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Authors: Askar Kilmametov, Julia Ivanisenko, Boris Straumal, Horst Hahn

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The high-pressure α- to ω-phase transition was discovered in elemental Ti and Zr fifty years ago using static high pressure and then observed to appear between 2 and 12 GPa at room temperature, depending on the experimental technique, the pressure environment, and the sample purity. The fact that ω-phase is retained in a metastable state in ambient condition after the removal of the pressure has been used to check the changes in magnetic and superconductive behavior, electron band structure and mechanical properties. However, the fundamental knowledge on a combination of both mechanical treatment and high applied pressure treatments for ω-phase formation in Ti alloys is currently lacking and has to be studied in relation to improved mechanical properties of bulk nanostructured states. In the present study, nanostructured (α+β) Ti alloys containing β-stabilizing elements such as Co, Fe, Cr, Nb were performed by severe plastic deformation, namely high pressure torsion (HPT) technique. HPT-induced α- to ω-phase transformation was revealed in dependence on applied pressure and shear strains by means of X-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. The transformation kinetics was compared with the kinetics of pressure-induced transition. Orientation relationship between α-, β- and ω-phases was taken into consideration and analyzed according to theoretical calculation proposed earlier. The influence of initial state before HPT appeared to be considerable for subsequent α- to ω-phase transition. Thermal stability of the HPT-induced ω-phase was discussed as well in the frame of mechanical behavior of Ti and Ti-based alloys produced by shear deformation under high applied pressure.

Keywords: bulk nanostructured materials, high pressure phase transitions, severe plastic deformation, titanium alloys

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Authors: Osama K. Abou-Zied, Saba A. Sulaiman

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We studied the spectroscopy of 25-nm diameter gold nanoparticles (AuNPs), coated with human serum albumin (HSA) as a model drug carrier. The morphology and coating of the AuNPs were examined using transmission electron microscopy and dynamic light scattering. Resonance energy transfer from the sole tryptophan of HSA (Trp214) to the AuNPs was observed in which the fluorescence quenching of Trp214 is dominated by a static mechanism. Using fluorescein (FL) to probe the warfarin drug-binding site in HSA revealed the unchanged nature of the binding cavity on the surface of the AuNPs, indicating the stability of the protein structure on the metal surface. The transient absorption results of the surface plasmonic resonance (SPR) band of the AuNPs show three ultrafast dynamics that are involved in the relaxation process after excitation at 460 nm. The three decay components were assigned to the electron-electron (~ 400 fs), electron-phonon (~ 2.0 ps) and phonon-phonon (200–250 ps) interactions. These dynamics were not changed upon coating the AuNPs with HSA which indicates the chemical and physical stability of the AuNPs upon bioconjugation. Binding of FL in HSA did not have any measurable effect on the bleach recovery dynamics of the SPR band, although both FL and AuNPs were excited at 460 nm. The current study is important for a better understanding of the physical and dynamical properties of protein-coated metal nanoparticles which are expected to help in optimizing their properties for critical applications in nanomedicine.

Keywords: gold nanoparticles, human serum albumin, fluorescein, femtosecond transient absorption

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Authors: Kwak, Hyo-Gyung, Gang, Han Gul

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In the context of an increasing need for reliability and safety in concrete structures under blast and impact loading condition, the behavior of concrete under high strain rate condition has been an important issue. Since concrete subjected to impact loading associated with high strain rate shows quite different material behavior from that in the static state, several material models are proposed and used to describe the high strain rate behavior under blast and impact loading. In the process of modelling, in advance, mesh dependency in the used finite element (FE) is the key problem because simulation results under high strain-rate condition are quite sensitive to applied FE mesh size. It means that the accuracy of simulation results may deeply be dependent on FE mesh size in simulations. This paper introduces an improved criterion which can minimize the mesh-dependency of simulation results on the basis of the fracture energy concept, and HJC (Holmquist Johnson Cook), CSC (Continuous Surface Cap) and K&C (Karagozian & Case) models are examined to trace their relative sensitivity to the used FE mesh size. To coincide with the purpose of the penetration test with a concrete plate under a projectile (bullet), the residual velocities of projectile after penetration are compared. The correlation studies between analytical results and the parametric studies associated with them show that the variation of residual velocity with the used FE mesh size is quite reduced by applying a unique failure strain value determined according to the proposed criterion.

Keywords: high strain rate concrete, penetration simulation, failure strain, mesh-dependency, fracture energy

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Authors: Eric Mxolisi Mkhondo

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Geometrical deviations and interaction of mechanical parts influences the performance of miniature systems.These deviations tend to cause costly problems during assembly due to imperfections of components, which are invisible to a naked eye.They also tend to cause unsatisfactory performance during operation due to deformation cause by environmental conditions.One of the effective tools to manage the deviations and interaction of parts in the system is tolerance analysis.This is a quantitative tool for predicting the tolerance variations which are defined during the design process.Traditional tolerance analysis assumes that the assembly is static and the deviations come from the manufacturing discrepancies, overlooking the functionality of the whole system and deformation of parts due to effect of environmental conditions. This paper presents an integrated tolerance analysis approach for miniature system in operation.In this approach, a computer-aided design (CAD) model is developed from system’s specification.The CAD model is then used to specify the geometrical and dimensional tolerance limits (upper and lower limits) that vary component’s geometries and sizes while conforming to functional requirements.Worst-case tolerances are analyzed to determine the influenced of dimensional changes due to effects of operating temperatures.The method is used to evaluate the nominal conditions, and worse case conditions in maximum and minimum dimensions of assembled components.These three conditions will be evaluated under specific operating temperatures (-40°C,-18°C, 4°C, 26°C, 48°C, and 70°C). A case study on the mechanism of a zoom lens system is used to illustrate the effectiveness of the methodology.

Keywords: geometric dimensioning, tolerance analysis, worst-case analysis, zoom lens mechanism

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Authors: Habtamu Tkubet Ebuy

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Purpose Conventional dynamic energy simulation tools go beyond the static dimension of simplified methods by providing better and more accurate prediction of building performance. However, their ability to forecast actual performance is undermined by a low representation of human interactions. The purpose of this study is to examine the potential benefits of incorporating information on occupant diversity into occupant behavior models used to simulate building performance. The co-simulation of the stochastic behavior of the occupants substantially increases the accuracy of the simulation. Design/methodology/approach In this article, probabilistic models of the "opening and closing" behavior of the window of inhabitants have been developed in a separate multi-agent platform, SimOcc, and implemented in the building simulation, TRNSYS, in such a way that the behavior of the window with the interconnectivity can be reflected in the simulation analysis of the building. Findings The results of the study prove that the application of complex behaviors is important to research in predicting actual building performance. The results aid in the identification of the gap between reality and existing simulation methods. We hope this study and its results will serve as a guide for researchers interested in investigating occupant behavior in the future. Research limitations/implications Further case studies involving multi-user behavior for complex commercial buildings need to more understand the impact of the occupant behavior on building performance. Originality/value This study is considered as a good opportunity to achieve the national strategy by showing a suitable tool to help stakeholders in the design phase of new or retrofitted buildings to improve the performance of office buildings.

Keywords: occupant behavior, co-simulation, energy consumption, thermal comfort

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Authors: Erfan Niazi, Marianne Fenech

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Red Blood Cells (RBCs) or erythrocytes tend to form chain-like aggregates under low shear rate called rouleaux. This is a reversible process and rouleaux disaggregate in high shear rates. Therefore, RBCs aggregation occurs in the microcirculation where low shear rates are present but does not occur under normal physiological conditions in large arteries. Numerical modeling of RBCs interactions is fundamental in analytical models of a blood flow in microcirculation. Population Balance Modeling (PBM) is particularly useful for studying problems where particles agglomerate and break in a two phase flow systems to find flow characteristics. In this method, the elementary particles lose their individual identity due to continuous destructions and recreations by break-up and agglomeration. The aim of this study is to find RBCs aggregation in a dynamic situation. Simplified PBM was used previously to find the aggregation rate on a static observation of the RBCs aggregation in a drop of blood under the microscope. To find aggregation rate in a dynamic situation we propose an experimental set up testing RBCs sedimentation. In this test, RBCs interact and aggregate to form rouleaux. In this configuration, disaggregation can be neglected due to low shear stress. A high-speed camera is used to acquire video-microscopic pictures of the process. The sizes of the aggregates and velocity of sedimentation are extracted using an image processing techniques. Based on the data collection from 5 healthy human blood samples, the aggregation rate was estimated as 2.7x10³(±0.3 x10³) 1/s.

Keywords: red blood cell, rouleaux, microfluidics, image processing, population balance modeling

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Authors: Mlondi Ndovela

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Globally, the manufacturing employment has been declining and the South African manufacturing sector experiences the very same trend. Despite the commonality between the global and South African manufacturing trend, there is an understanding that local areas provide distinct contributions to the provincial/national economy. Therefore, the growth/decline of a particular manufacturing division in one local area may not be evident in another area since economic performances vary from region to region. In view of the above, the study employed the Esteban-Marquillas model of shift-share analysis (SSA) to conduct an empirical analysis of manufacturing employment performance at uMhlathuze Local Municipality in the KwaZulu-Natal province. The study set out two objectives; those are, to quantify uMhlathuze manufacturing jobs that are attributed to the provincial manufacturing employment trends and identify manufacturing divisions are growing/declining in terms of employment. To achieve these objectives, the study sampled manufacturing employment data from 2010 to 2017 and this data was categorised into ten manufacturing divisions. Furthermore, the Esteban-Marquillas model calculated manufacturing employment in terms of two effects, namely; provincial growth effect (PGE) and industrial mix effect (IME). The results show that even though uMhlathuze manufacturing sector has a positive PGE (+230), the municipality performed poorly in terms of IME (-291). A further analysis included other economic sectors of the municipality to draw employment performance comparison and the study found that agriculture; construction; trade, catering and accommodation; and transport, storage and communication, performed well above manufacturing sector in terms of PGE (+826) and IME (+532). This suggests that uMhlathuze manufacturing sector is not necessarily declining; however, other economic sectors are growing faster and bigger than it is, therefore, reducing the employment share of the manufacturing sector. To promote manufacturing growth from a policy standpoint, the government could create favourable macroeconomic policies such as import substitution policies and support labour-intensive manufacturing divisions. As a result, these macroeconomic policies can help to protect local manufacturing firms and stimulate the growth of manufacturing employment.

Keywords: allocation effect, Esteban-Marquillas model, manufacturing employment, regional competitive effect, shift-share analysis

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Authors: Akinsola Oluwatosin, Udofia Samuel, Odofin Mayowa

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The study is aimed at assessing the Geographic Information System (GIS)-based spatial analysis of Survival Pattern and Treatment Outcomes of Multi-Drug Resistant Tuberculosis (MDR-TB) cases for Lagos, Nigeria, with an objective to inform priority areas for public health planning and resource allocation. Multi-drug resistant tuberculosis (MDR-TB) develops due to problems such as irregular drug supply, poor drug quality, inappropriate prescription, and poor adherence to treatment. The shapefile(s) for this study were already georeferenced to Minna datum. The patient’s information was acquired on MS Excel and later converted to . CSV file for easy processing to ArcMap from various hospitals. To superimpose the patient’s information the spatial data, the addresses was geocoded to generate the longitude and latitude of the patients. The database was used for the SQL query to the various pattern of the treatment. To show the pattern of disease spread, spatial autocorrelation analysis was used. The result was displayed in a graphical format showing the areas of dispersing, random and clustered of patients in the study area. Hot and cold spot analysis was analyzed to show high-density areas. The distance between these patients and the closest health facility was examined using the buffer analysis. The result shows that 22% of the points were successfully matched, while 15% were tied. However, the result table shows that a greater percentage of it was unmatched; this is evident in the fact that most of the streets within the State are unnamed, and then again, most of the patients are likely to supply the wrong addresses. MDR-TB patients of all age groups are concentrated within Lagos-Mainland, Shomolu, Mushin, Surulere, Oshodi-Isolo, and Ifelodun LGAs. MDR-TB patients between the age group of 30-47 years had the highest number and were identified to be about 184 in number. The outcome of patients on ART treatment revealed that a high number of patients (300) were not ART treatment while a paltry 45 patients were on ART treatment. The result shows the Z-score of the distribution is greater than 1 (>2.58), which means that the distribution is highly clustered at a significance level of 0.01.

Keywords: tuberculosis, patients, treatment, GIS, MDR-TB

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Authors: Tanjil Sowgat, Shamim Kobir

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World is now experiencing the consequences of climate change such as increased heat stress due to high temperature rise. In the context of changing climate, this study intends to find out the planning interventions necessary to adapt to the current heat stress in the planned residential areas of Khulna city. To carry out the study Sonadanga residential area (phase I) of Khulna city has been taken as the study site. This residential neighbourhood covering an area of 30 acres has 206 residential plots. The study area comprises twelve access roads, one park, one playfield, one water body and two street furniture’s. This study conducts visual analysis covering green, open space, water body, footpath, drainage and street trees and furniture and questionnaire survey deals with socio-economic, housing tenancy, experience of heat stress and urban design interventions. It finds that the current state that accelerates the heat stress condition such as lack of street trees and inadequate shading, maximum uses are not within ten minutes walking distance, no footpath for the pedestrians and lack of well-maintained street furniture. It proposes that to adapt to the heat stress pedestrian facilities, buffer sidewalk with landscaping, street trees and open spaces, soft scape, natural and man-made water bodies, green roofing could be effective urban design interventions. There are evidences of limited number of heat stress adaptive planned residential area. Since current sub-division planning practice focuses on rigid land use allocation, it partly addresses the climatic concerns through creating open space and street trees. To better respond to adapt to the heat stress, urban design considerations in the context of sub-division practice would bring more benefits.

Keywords: climate change, urban design, adaptation, heat stress, water-logging

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Authors: Vijaya Subramaniam, Loh Soh Kheang, Astimar Abdul Aziz

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Water footprint (WFP) has gained importance due to the increase in water scarcity in the world. This study analyses the WFP for an agriculture sector, i.e., the oil palm supply chain, which produces oil palm fresh fruit bunch (FFB), crude palm oil, palm kernel, and crude palm kernel oil. The water accounting and vulnerability evaluation (WAVE) method was used. This method analyses the water depletion index (WDI) based on the local blue water scarcity. The main contribution towards the WFP at the plantation was the production of FFB from the crop itself at 0.23m³/tonne FFB. At the mill, the burden shifts to the water added during the process, which consists of the boiler and process water, which accounted for 6.91m³/tonne crude palm oil. There was a 33% reduction in the WFP when there was no dilution or water addition after the screw press at the mill. When allocation was performed, the WFP reduced by 42% as the burden was shared with the palm kernel and palm kernel shell. At the kernel crushing plant (KCP), the main contributor towards the WFP 4.96 m³/tonne crude palm kernel oil which came from the palm kernel which carried the burden from upstream followed by electricity, 0.33 m³/tonne crude palm kernel oil used for the process and 0.08 m³/tonne crude palm kernel oil for transportation of the palm kernel. A comparison was carried out for mills with biogas capture versus no biogas capture, and the WFP had no difference for both scenarios. The comparison when the KCPs operate in the proximity of mills as compared to those operating in the proximity of ports only gave a reduction of 6% for the WFP. Both these scenarios showed no difference and insignificant difference, which differed from previous life cycle assessment studies on the carbon footprint, which showed significant differences. This shows that findings change when only certain impact categories are focused on. It can be concluded that the impact from the water used by the oil palm tree is low due to the practice of no irrigation at the plantations and the high availability of water from rainfall in Malaysia. This reiterates the importance of planting oil palm trees in regions with high rainfall all year long, like the tropics. The milling stage had the most significant impact on the WFP. Mills should avoid dilution to reduce this impact.

Keywords: life cycle assessment, water footprint, crude palm oil, crude palm kernel oil, WAVE method

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Authors: Diyar Yousif Ali

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Braced frames, besides other structural systems, such as shear walls or moment resisting frames, have been a valuable and effective technique to increase structures against seismic loads. In wind or seismic excitations, diagonal members react as truss web elements which would afford tension or compression stresses. This study proposes to consider the effect of bracing diagonal configuration on values of base shear and displacement of building. Two models were created, and nonlinear pushover analysis was implemented. Results show that bracing members enhance the lateral load performance of the Concentric Braced Frame (CBF) considerably. The purpose of this article is to study the nonlinear response of reinforced concrete structures which contain hollow pipe steel braces as the major structural elements against earthquake loads. A five-storey reinforced concrete structure was selected in this study; two different reinforced concrete frames were considered. The first system was an un-braced frame, while the last one was a braced frame with diagonal bracing. Analytical modelings of the bare frame and braced frame were realized by means of SAP 2000. The performances of all structures were evaluated using nonlinear static analyses. From these analyses, the base shear and displacements were compared. Results are plotted in diagrams and discussed extensively, and the results of the analyses showed that the braced frame was seemed to capable of more lateral load carrying and had a high value for stiffness and lower roof displacement in comparison with the bare frame.

Keywords: reinforced concrete structures, pushover analysis, base shear, steel bracing

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Authors: Jason R. King, Hugh H. T. Liu

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This research presents simulation and experimental work in the visual servoing of a quadrotor Unmanned Aerial Vehicle (UAV) to stabilize overtop of a moving target. Most previous work in the field assumes static or slow-moving, unpredictable targets. In this experiment, the target is assumed to be a friendly ground robot moving freely on a horizontal plane, which shares information with the UAV. This information includes velocity and acceleration information of the ground target to aid the quadrotor in its tracking task. The quadrotor is assumed to have a downward-facing camera which is fixed to the frame of the quadrotor. Only onboard sensing for the quadrotor is utilized for the experiment, with a VICON motion capture system in place used only to measure ground truth and evaluate the performance of the controller. The experimental platform consists of an ArDrone 2.0 and a Create Roomba, communicating using Robot Operating System (ROS). The addition of the target’s information is demonstrated to help the quadrotor in its tracking task using simulations of the dynamic model of a quadrotor in Matlab Simulink. A nested PID control loop is utilized for inner-loop control the quadrotor, similar to previous works at the Flight Systems and Controls Laboratory (FSC) at the University of Toronto Institute for Aerospace Studies (UTIAS). Experiments are performed with ground truth provided by an indoor motion capture system, and the results are analyzed. It is demonstrated that a velocity controller which incorporates the additional information is able to perform better than the controllers which do not have access to the target’s information.

Keywords: quadrotor, target tracking, unmanned aerial vehicle, UAV, UAS, visual servoing

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Authors: Tolulope Babawarun, Harry Ngwangwa

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The wind turbine blade may sustain structural damage from external loads such as high winds or collisions, which could compromise its aerodynamic efficiency. The wind turbine blade vibrates at significant intensities and amplitudes under these conditions. The effect of these vibrations on the dynamic flow field surrounding the blade changes the forces operating on it. The structural dynamic analysis of a small wind turbine blade is considered in this study. It entails creating a finite element model, validating the model, and doing structural analysis on the verified finite element model. The analysis is based on the structural reaction of a small-scale wind turbine blade to various loading sources. Although there are many small-scale off-shore wind turbine systems in use, only preliminary structural analysis is performed during design phases; these systems' performance under various loading conditions as they are encountered in real-world situations has not been properly researched. This will allow us to record the same Equivalent von Mises stress and deformation that the blade underwent. A higher stress contour was found to be more concentrated near the middle span of the blade under the various loading scenarios studied. The highest stress that the blade in this study underwent is within the range of the maximum stress that blade material can withstand. The maximum allowable stress of the blade material is 1,770 MPa. The deformation of the blade was highest at the blade tip. The critical speed of the blade was determined to be 4.3 Rpm with a rotor speed range of 0 to 608 Rpm. The blade's mode form under loading conditions indicates a bending mode, the most prevalent of which is flapwise bending.

Keywords: ANSYS, finite element analysis, static loading, dynamic analysis

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