Search results for: allowable maximum displacement

Authors: Humayun R. H. Kabir

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An analytical solution before used for static and free-vibration response has been extended for thermal buckling response on cylindrical panel with anti-symmetric laminations. The partial differential equations that govern kinematic behavior of shells produce five coupled differential equations. The basic displacement and rotational unknowns are similar to first order shear deformation theory---three displacement in spatial space, and two rotations about in-plane axes. No drilling degree of freedom is considered. Boundary conditions are considered as complete hinge in all edges so that the panel respond on thermal inductions. Two sets of double Fourier series are considered in the analytical solution process. The sets are selected that satisfy mixed type of natural boundary conditions. Numerical results are presented for the first 10 eigenvalues, and first 10 mode shapes for Ux, Uy, and Uz components. The numerical results are compared with a finite element based solution.

Keywords: higher order shear deformation, composite, thermal buckling, angle-ply laminations

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Authors: Chiang-Ho Cheng, An-Shik Yang, Hon-Yi Cheng, Ming-Yu Lai

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This paper presents the design and fabrication of a novel piezoelectric actuator for a gas micropump with check valve having the advantages of miniature size, light weight and low power consumption. The micropump is designed to have eight major components, namely a stainless steel upper cover layer, a piezoelectric actuator, a stainless steel diaphragm, a PDMS chamber layer, two stainless steel channel layers with two valve seats, a PDMS check valve layer with two cantilever-type check valves and an acrylic substrate. A prototype of the gas micropump, with a size of 52 mm × 50 mm × 5.0 mm, is fabricated by precise manufacturing. This device is designed to pump gases with the capability of performing the self-priming and bubble-tolerant work mode by maximizing the stroke volume of the membrane as well as the compression ratio via minimization of the dead volume of the micropump chamber and channel. By experiment apparatus setup, we can get the real-time values of the flow rate of micropump and the displacement of the piezoelectric actuator, simultaneously. The gas micropump obtained higher output performance under the sinusoidal waveform of 250 Vpp. The micropump achieved the maximum pumping rates of 1185 ml/min and back pressure of 7.14 kPa at the corresponding frequency of 120 and 50 Hz.

Keywords: PDMS, check valve, micropump, piezoelectric

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Authors: Loonibha Manandhar, Rajendra Bhandari, Kumud Raj Kafle

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Nepal’s Terai region is a part of the Ganges river basin which is one of the most disaster-prone areas of the world, with recurrent monsoon flooding causing millions in damage and the death and displacement of hundreds of people and households every year. The vulnerability of human settlements to natural disasters such as floods is increasing, and mapping changes in land use practices and hydro-geological parameters is essential in developing resilient communities and strong disaster management policies. The objective of this study was to develop a flood hazard zonation map of Orai Khola watershed and map the decadal land use/land cover dynamics of the watershed. The watershed area was delineated using SRTM DEM, and LANDSAT images were classified into five land use classes (forest, grassland, sediment and bare land, settlement area and cropland, and water body) using pixel-based semi-automated supervised maximum likelihood classification. Decadal changes in each class were then quantified using spatial modelling. Flood hazard mapping was performed by assigning weights to factors slope, rainfall distribution, distance from the river and land use/land cover on the basis of their estimated influence in causing flood hazard and performing weighed overlay analysis to identify areas that are highly vulnerable. The forest and grassland coverage increased by 11.53 km² (3.8%) and 1.43 km² (0.47%) from 1996 to 2016. The sediment and bare land areas decreased by 12.45 km² (4.12%) from 1996 to 2016 whereas settlement and cropland areas showed a consistent increase to 14.22 km² (4.7%). Waterbody coverage also increased to 0.3 km² (0.09%) from 1996-2016. 1.27% (3.65 km²) of total watershed area was categorized into very low hazard zone, 20.94% (60.31 km²) area into low hazard zone, 37.59% (108.3 km²) area into moderate hazard zone, 29.25% (84.27 km²) area into high hazard zone and 31 villages which comprised 10.95% (31.55 km²) were categorized into high hazard zone area.

Keywords: flood hazard, land use/land cover, Orai river, supervised maximum likelihood classification, weighed overlay analysis

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Authors: Mehdi Ameur, Ahmed Essakdi, Tamou Nasser

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The purpose of this paper is the analysis and modeling of the photovoltaic system with MPPT techniques. This system is developed by combining the models of established solar module and DC-DC converter with the algorithms of perturb and observe (P&O), incremental conductance (INC) and fuzzy logic controller(FLC). The system is simulated under different climate conditions and MPPT algorithms to determine the influence of these conditions on characteristic power-voltage of PV system. According to the comparisons of the simulation results, the photovoltaic system can extract the maximum power with precision and rapidity using the MPPT algorithms discussed in this paper.

Keywords: photovoltaic array, maximum power point tracking, MPPT, perturb and observe, P&O, incremental conductance, INC, hill climbing, HC, fuzzy logic controller, FLC

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Authors: Geochul Jeong, In-Gun Kim, Hyun-Seok Hong, Dong-Woo Kang, Ju Lee

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This study is about IPMSM design for obtaining the maximum traction force of Tram-Train. Tram-Train is a Tram and Train-combined railway vehicles, which operates at a maximum speed of 70km/h in the city section (Tram section) and at a maximum speed of 150km/h in the out-of-city section (Train section). For this reason, tram-train was designed to be an IPMSM (Interior Permanent Synchronous Motor) with a wide range of speed variation. IPMSM’s magnetic path varies depending on the shape of rotor and in this case, the power characteristics are different in the constant torque area and the flux weakening area. Therefore, this study suggests a method to improve Tram-Train’s traction force, based on the relationship between magnetic torque and reluctance torque. The suggested method was applied through IPMSM rotor shape design and electromagnetic field finite element method was conducted to verify the validity of the suggested method.

Keywords: tram-train, traction motor, IPMSM, synchronous motor, railway vehicles

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Authors: Vanessa A. Segovia, Sonia E. Ruiz

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The use of energy dissipation systems for seismic applications has increased worldwide, thus it is necessary to develop practical and modern criteria for their optimal design. Here, a direct displacement-based seismic design approach for frame buildings with hysteretic energy dissipation systems (HEDS) is applied. The building is constituted by two individual structural systems consisting of: 1) A main elastic structural frame designed for service loads and 2) A secondary system, corresponding to the HEDS, that controls the effects of lateral loads. The procedure implies to control two design parameters: A) The stiffness ratio (α=K_frame/K_(total system)), and B) The strength ratio (γ= V_damper / V_(total system)). The proposed damage-controlled approach contributes to the design of a more sustainable and resilient building because the structural damage is concentrated on the HEDS. The reduction of the design displacement spectrum is done by means of a damping factor (recently published) for elastic structural systems with HEDS, located in Mexico City. Two limit states are verified: Serviceability and near collapse. Instead of the traditional trial-error approach, a procedure that allows the designer to establish the preliminary sizes of the structural elements of both systems is proposed. The design methodology is applied to an 8-story steel building with buckling restrained braces, located in soft soil of Mexico City. With the aim of choosing the optimal design parameters, a parametric study is developed considering different values of α and γ. The simplified methodology is for preliminary sizing, design, and evaluation of the effectiveness of HEDS, and it constitutes a modern and practical tool that enables the structural designer to select the best design parameters.

Keywords: damage-controlled buildings, direct displacement-based seismic design, optimal hysteretic energy dissipation systems, hysteretic dampers

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Authors: Kinza Khan, Dad Muhmmad, Asif Saleem, Nadia Mukhtar, Tahir Yaqub

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Ethomedicines are more commonly used in underdeveloped and developing countries. These medicines are sometimes more potent in controlling microbial infections than conventional medicines. Medicinal plants have been common practice to cure many diseases for centuries. Murraya koenigii is one of these plants and is commonly used in South Asian countries as a flavoring agent in food. To evaluate its anti-microbial activity, six different bacterial strains (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi, Bacillus cereus and Klebsiella pneumonia were used. N-hexane extract of Murraya koenigii leaves shows maximum activity against Bacillus cereus. Acetone extract of Murraya koenigii shoots showed more efficient activity against Pseudomonas aeruginosa Dichloromethane extracts showed maximum activity against Bacillus cereus. Ethanol extract exhibited maximum activity against Pseudomonas aeruginosa and Klebsiella pneumoniae. The methanol extract of Murraya koenigii shoots displayed maximum antibacterial activity against Bacillus cereus. Antifungal activity Ethanol extract was more effective against Candida albicans.

Keywords: ethnomedicines, bacteria, fungi, murraya koenigii, antimicrobial activity

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Authors: José Davi Oliveira De Moura, Chou Sin Chan

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In this study, the effect of convective momentum transport (CMT) on the life of cyclone systems and their organization is analyzed. A case of strong precipitation, in the southeast of Brazil, was simulated using Eta model with two kinds of convective parameterization: Kain-Fritsch without CMT and Kain-fritsch with CMT. Reanalysis data from CFSR were used to compare Eta model simulations. The Wind, mean sea level pressure, rain and temperature are included in analysis. The rain was evaluated by Equitable Threat Score (ETS) and Bias Index; the simulations were compared among themselves to detect the influence of CMT displacement on the systems. The result shows that CMT process decreases the intensity of meso cyclones (higher pressure values on nuclei) and change the positions and production of rain. The decrease of intensity in meso cyclones should be caused by the dissolution of momentum from lower levels from up levels. The rain production and rain distribution were altered because the displacement of the larger systems scales was changed. In addition, the inclusion of CMT process is very important to improve the simulation of life time of meteorological systems.

Keywords: convection, Kain-Fritsch, momentum, parameterization

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Authors: Sharifullah Ahmed, Sarwar Jahan Md. Yasin

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Shallow foundations on unimproved soft natural soils can undergo a high consolidation and secondary settlement. For low and medium rise building projects on such soil condition, pile foundation may not be cost effective. In such cases an alternative to pile foundations may be shallow strip footings placed on a double layered improved soil system soil. The upper layer of this system is untreated or cement treated compacted sand and underlying layer is natural soft clay. This system will reduce the settlement to an allowable limit. The current research has been conducted with the settlement of a rigid plane-strain strip footing of 2.5 m width placed on the surface of a soil consisting of an untreated or cement treated sand layer overlying a bed of homogeneous soft clay. The settlement of the mentioned shallow foundation has been studied considering both cases with the thicknesses of the sand layer are 0.3 to 0.9 times the width of footing. The response of the clay layer is assumed as undrained for plastic loading stages and drained during consolidation stages. The response of the sand layer is drained during all loading stages. FEM analysis was done using PLAXIS 2D Version 8.0. A natural clay deposit of 15 m thickness and 18 m width has been modeled using Hardening Soil Model, Soft Soil Model, Soft Soil Creep Model, and upper improvement layer has been modeled using only Hardening Soil Model. The groundwater level is at the top level of the clay deposit that made the system fully saturated. Parametric study has been conducted to determine the effect of thickness, density, cementation of the sand mat and density, shear strength of the soft clay layer on the settlement of strip foundation under the uniformly distributed vertical load of varying value. A set of the chart has been established for designing shallow strip footing on the sand mat over thick, soft clay deposit through obtaining the particular thickness of sand mat for particular subsoil parameter to ensure no punching shear failure and no settlement beyond allowable level. Design guideline in the form of non-dimensional charts has been developed for footing pressure equivalent to medium-rise residential or commercial building foundation with strip footing on soft inorganic Normally Consolidated (NC) soil of Bangladesh having void ratio from 1.0 to 1.45.

Keywords: design charts, ground improvement, PLAXIS 2D, primary and secondary settlement, sand mat, soft clay

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Authors: Sunthari Tharapan, Chockpisit Thepsithar, Kullanart Obsuwan

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This study was aimed to investigate the effect of various organic supplements on growth and development of Dendrobium discolor’s protocorms and seedlings growth of Dendrobium Judy Rutz. Protocorms of Dendrobium discolor with 2.0 cm. in diameter and seedlings of Dendrobium Judy Rutz at the same size (0.5 cm. height) were sub-cultured on Hyponex medium supplemented with cow milk (CM), soy milk (SM), potato extract (PE) and peptone (P) for 2 months. The protocorms were developed to seedlings in all treatments after cultured for 2 months. However, the best results were found on Hyponex medium supplemented with P was the best in which the maximum fresh and dry weight and maximum shoot height were obtained in this treatment statistically different (p ≤ 0.05) to other treatments. Moreover, Hyponex medium supplemented with P also stimulated the maximum mean number of 5.7 shoots per explant which also showed statistically different (p ≤ 0.05) when compared to other treatments. The results of growth of Dendrobium Judy Rutz seedlings indicated the medium supplemented with 100 mL/L PE enhanced the maximum fresh and dry weigh per explants with significantly different (p ≤ 0.05) in fresh weight from other treatments including the control medium without any organic supplementation. However, the dry weight was not significantly different (p ≤ 0.05) from medium supplemented with SM and P. There was multiple shoots induction in all media with or without organic supplementation ranging from 2.6 to 3 shoots per explants. The maximum shoot height was also obtained in the seedlings cultured on medium supplemented with PE while the longest root length was found in medium supplemented with SM.

Keywords: fresh weight, in vitro propagation, orchid, plant height

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Authors: Abdolrasoul Daneshjoo

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Soccer is a game which draws more attention in different countries especially in Brazil. Kicking among different skills in soccer and soccer players is an excellent role for the success and preference of a team. The way of point gaining in this game is passing the ball over the goal lines which are gained by shoot skill in attack time and or during the penalty kicks.Regarding the above assumption, identifying the effective factors in instep kicking in different distances shoot with maximum force and high accuracy or pass and penalty kick, may assist the coaches and players in raising qualitative level of performing the skill.The aim of the present study was to study of a few kinematical parameters in instep kicking from 5 and 7 meter distance among the male and female elite soccer players.24 right dominant lower limb subjects (12 males and 12 females) among Tehran elite soccer players with average and the standard deviation (22.5 ± 1.5) & (22.08± 1.31) years, height of (179.5 ± 5.81) & (164.3 ± 4.09) cm, weight of (69.66 ± 4.09) & (53.16 ± 3.51) kg, %BMI (21.06 ± .731) & (19.67 ± .709), having playing history of (4 ± .73) & (3.08 ± .66) years respectively participated in this study. They had at least two years of continuous playing experience in Tehran soccer league.For sampling player's kick; Kinemetrix Motion analysis with three cameras with 1000 Hz was used. Five reflective markers were placed laterally on the kicking leg over anatomical points (the iliac crest, major trochanter, lateral epicondyle of femur, lateral malleolus, and lateral aspect of distal head of the fifth metatarsus). Instep kick was filmed, with one step approach and 30 to 45 degrees angle from stationary ball. Three kicks were filmed, one kick selected for further analyses. Using Kinemetrix 3D motion analysis software, the position of the markers was analyzed. Descriptive statistics were used to describe the mean and standard deviation, while the analysis of variance, and independent t-test (P < 0.05) were used to compare the kinematic parameters between two genders.Among the evaluated parameters, the knee acceleration, the thigh angular velocity, the angle of knee proportionately showed significant relationship with consequence of kick. While company performance on 5m in 2 genders, significant differences were observed in internal – external displacement of toe, ankle, hip and the velocity of toe, ankle and the acceleration of toe and the angular velocity of pelvic, thigh and before time contact . Significant differences showed the internal – external displacement of toe, the ankle, the knee and the hip, the iliac crest and the velocity of toe, the ankle and acceleration of ankle and angular velocity of the pelvic and the knee.

Keywords: biomechanics, kinematics, instep kicking, soccer

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Authors: Waseim Ragab Azzam Ahmed Mohamed Nasr, Aalaa Ibrahim Khater

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Torsional loads from offshore wind turbines, waves, wind, earthquakes, ship collisions in the maritime environment, and electrical transmission towers might affect the pile foundations. Torsional loads can also be caused by the axial load from the sustaining structures. The paper introduces the finned pile, an alternative method of pile modification. The effects of torsional loads were investigated through a series of experimental tests aimed at improving the torsional capacity of a single pile in the sand (where sand was utilized in a state of medium density (Dr = 50%), with or without fins. In these tests, the fins' length, width, form, and number were varied to see how these attributes affected the maximum torsional capacity of the piles. We have noticed the torsion-rotation reaction. The findings demonstrated that the fins improve the maximum torsional capacity of the piles. It was demonstrated that a length of 0.6 times the embedded pile's length and a width equivalent to the pile's diameter constitute the optimal fin geometry. For the conventional pile and the finned pile, the maximum torsional capacities were determined to be 4.12 N.m. and 7.36 N.m., respectively. When subjected to torsional loads, the fins' presence enhanced the piles' maximum torsional capacity by almost 79%.

Keywords: clean sand, finned piles, model tests, torsional load

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Authors: Muhammad Mamoon-Ur-Rashid, Gul Rehman

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Entomopathogenic fungi are considered effective bio-control agents for the management of a range of insect pests including red palm weevil. The research studies were conducted under laboratory and field conditions against 5th and 6th instars larvae and adults of [Rhynchophorus ferrugineus (Olivier)] at the faculty of Agriculture, Gomal University Dera Ismail Khan (KPK) Pakistan. The 5th instar larvae were used under field conditions whereas, the 6th instar larvae and newly emerged adults were used under lab conditions. Conidial suspensions were used at five different concentrations of 1×10⁴, 1×10⁵, 1×10⁶, 1×10⁷ and 1×10⁸, conidia per ml. The data were recorded on the mortality, total larval duration, weight of larvae, pre-pupal and pupal durations, percent pupal formation, pupal weight, percent adult emergence, and adult longevity (♂ and ♀) of red palm weevil. The B. bassiana had varying degrees of pathogenicity against different developmental stages of red palm weevil. The maximum larval duration (113.40 days) was noted when 5th instar larvae were treated with the maximum concentration (1 × 10⁸) of B. bassiana, whereas; the minimum total larval duration of 87.20 days was recorded on the lowest concentration (1 × 10⁴) of B. bassiana. The maximum pre-pual and pupal durations were noted at the maximum concentration. The maximum life span of adult male and females were noted at the lowest concentration, whereas; the minimum values were noted at the maximum concentration. The earliest mortality of red palm weevil was observed 1-day after treatment at higher concentrations of 1 × 10⁷ and 1 × 10⁸, whereas; it was recorded 3 and 4 days after treatment at lower concentrations of 1 × 10⁵ and 1 × 10⁴. At 10 days after treatment, the entomopathogenic fungus caused > 80% cumulative mortality of 5th and 6th instar larvae and adult weevils at the maximum concentrations which were more than double than those recorded at the lowest concentration. Overall, the 5th instar larvae of red palm weevils were most susceptible to the fungus compared to the 6th instar larvae and adult weevils. Based on current findings, it is suggested that entomopathogenic fungi could be used for the safer management of red palm weevil.

Keywords: entomopathogenic nematodes, mortality, red palm weevil, sub-lethal effects

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Authors: C. J. W. Habets, D. J. Peters, J. G. de Gijt, A. V. Metrikine, S. N. Jonkman

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Conventional seismic designs of quay walls in ports are mostly based on pseudo-static analysis. A more advanced alternative is the Performance-Based Design (PBD) method, which evaluates permanent deformations and amounts of (repairable) damage under seismic loading. The aim of this study is to investigate the suitability of this method for anchored sheet pile quay walls that were not purposely designed for seismic loads. A research methodology is developed in which pseudo-static, permanent-displacement and finite element analysis are employed, calibrated with an experimental reference case that considers a typical anchored sheet pile wall. A reduction factor that accounts for deformation behaviour is determined for pseudo-static analysis. A model to apply traditional permanent displacement analysis on anchored sheet pile walls is proposed. Dynamic analysis is successfully carried out. From the research it is concluded that PBD evaluation can effectively be used for seismic analysis and design of this type of structure.

Keywords: anchored sheet pile quay wall, simplified dynamic analysis, performance-based design, pseudo-static analysis

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Authors: Arslan Shehroz, Muhammad Amjad Ali, Amjad Abbas, Imran Ramzan, Muhammad Zunair Latif

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Potato (Solanum tuberosum L.) is the 4th most important food crop of the world after wheat, rice and maize. It is the staple food in many European countries. Being rich in starch (one of the main three food ingredients) and having the highest productivity per unit area, has great potential to address the challenge of the food security. Processed potato is also used as chips and crisps etc as ‘fast food’. There are many biotic and abiotic factors which check the production of potato and become hurdle in achievement production potential of potato. 20 new varieties along with two checks were evaluated. Plant to plant and row to row distances were maintained as 20 cm and 75 cm, respectively. The trial was conducted according to the randomized complete block design with three replications. Normal agronomic and plant protection measures were carried out in the crop. It is revealed from the experiment that exotic variety 171 gave the highest yield of 35.5 t/ha followed by Masai with 31.0 t/ha tuber yield. The check variety Simply Red 24.2 t/ha yield, while the lowest tuber yield (1.5 t/ha) was produced by the exotic variety KWS-06-125. The maximum emergence was shown by the Variety Red Sun (89.7 %). The lowest emergence was shown by the variety Camel (71.7%). Regarding tuber grades, it was noted that the maximum Ration size tubers were produced by the exotic variety Compass (3.7%), whereas 11 varieties did not produce ration size tubers at all. The variety Red Sun produced lowest percentage of small size tubers (12.7%) whereas maximum small size tubers (93.0%) were produced by the variety Jitka. Regarding disease infestation, it was noted that the maximum scab incidence (4.0%) was recorded on the variety Masai, maximum rhizoctonia attack (60.0%) was recorded on the variety Camel and maximum tuber cracking (0.7%) was noted on the variety Vendulla.

Keywords: check variety, potato, potential and yield, trial

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Authors: Jun Ha Whang

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As New York City weathers a swelling 'affordability crisis' marked by rapid transformation in land development and urban culture, much of the associated scholarly debate has turned to questions of the underlying mechanisms of gentrification. Though classically approached from the point of view of urban planning, increasingly these questions have been addressed with an eye to understanding the role of cultural capital in neighborhood valuation. This paper will examine the construction of an artist-specific affordable housing development in the Spanish Harlem neighborhood of Manhattan in order to identify and discuss several cultural parameters of gentrification. This study’s goal is not to argue that the development in question, named Art space PS 109, straightforwardly increases or decreases the rate of gentrification in Spanish Harlem, but rather to study dynamics present in the construction of Art space PS 109 as a case study considered against the broader landscape of gentrification in New York, particularly with respect to the impact of artist communities on housing supply. In the end, what Art space PS 109 most valuably offers us is a reference point for a comparative analysis of affordable housing strategies currently being pursued within municipal government. Our study of Art space PS 109 has allowed us to examine a microcosm of the city’s response and evaluate its overall strategy accordingly. As a base line, the city must aggressively pursue an affordability strategy specifically suited to the needs of each of its neighborhoods. It must also conduct this in such a way so as not to undermine its own efforts by rendering them susceptible to the exploitative involvement of real estate developers seeking to identify successive waves of trendy neighborhoods. Though Art space PS 109 offers an invaluable resource for the city’s legitimate aim of preserving its artist communities, with such a high inclusion rate of artists from outside of the community the project risks additional displacement, strongly suggesting the need for further study of the implications of sites of cultural capital for neighborhood planning.

Keywords: artist housing, displacement, east Harlem, urban planning

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Authors: Moudar Zgoul, Hashem Alkhaldi

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A large number of transportable LPG cylinders are manufactured annually for domestic use. These LPG cylinders are manufactured from mild steel and filled maximally with 12.5 kg liquefied gas under internal pressure of 0.6 N/mm² at a temperature of 50°C. Many millions of such LPG cylinders are in daily use mainly, for purposes of space heating, water heating, and cooking. Thereby, they are imposed to severe conditions leading to their failure. Each year not less than 5000 of these LPG cylinders fail, some of those failures cause damage and loss in lives and properties. In this work, LPG cylinders were investigated; Stress calculations and deformations under dynamic (impact) loadings were carried out to simulate the effects of such loads on the cylinders while in service. Analysis of the LPG cylinders was carried out using the finite element method; shell and cylindrical elements were used at the top, bottom, and in middle (weld region), permitting elastic-plastic analysis for a thin-walled LPG cylinder. Variables such as maximum stresses and maximum deflections under the effect of impact loading were investigated in this work. Results showed that the maximum stresses reach 680 MPa when dropped from 3m-height. The maximum radial deformation occurs at the cylinder’s top in case of the top-position impact. This information should be useful for enhancing the strength of such cylinders and to for prolonging their service life.

Keywords: dynamic analysis, finite element method, impact load, LPG cylinders

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Authors: Kevin T. Inks

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India’s Brahmaputra River Valley has, since independence, experienced consistent low-intensity guerrilla warfare between ethnic and religious groups. These groups are often organized around perceived ethnic territoriality, and target civilians, communities, and especially migrants belonging to other ethnic and religious groups. Intense flooding and erosion have led to widespread displacement, and disaster relief funds are largely tied to legal land tenure. Displaced residents of informal settlements receive little or no resettlement aid, and their subsequent migration strategies and risk from guerrilla violence are poorly understood. Semi-structured interviews and comprehensive surveys focused on perceptions of risk, efficacy of disaster relief, and migration and adaptation strategies were conducted with households identified as being ‘at-risk’ of catastrophic flooding and erosion in Majuli District, Assam. Interviews with policymakers and government workers were conducted to assess disaster relief efforts in informal settlements, and remote sensing methods were used to identify informal settlement and hydrogeomorphic change. The results show that various ethnic and religious groups have differential strategies and preferences for resettlement. However, these varying strategies are likely to lead to differential levels of risk from guerrilla violence. Members of certain ethnic groups residing in informal settlements, in the absence of resettlement assistance, are more likely to seek out unofficial settlement on land far from the protection of the state and experience greater risk of becoming victims of political violence. As climate change and deforestation are likely to increase the severity of the displacement crisis in the Brahmaputra River Valley, more comprehensive disaster relief and surveying efforts are vital for limiting migration and informal settlement in potential sites of guerrilla warfare.

Keywords: climate, displacement, flooding, India, violence

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Authors: Manuel A. Guzman, Davide Forcellini, Ricardo Moreno, Diego H. Giraldo

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Elastomeric bearings (EB) are used in many applications, such as base isolation of bridges, seismic protection and vibration control of other structures and machinery. Their versatility is due to their particular behavior since they have different stiffness in the vertical and horizontal directions, allowing to sustain vertical loads and at the same time horizontal displacements. Therefore, vertical, horizontal and bending stiffnesses are important parameters to take into account in the design of EB. In order to acquire a proper design methodology of EB all three, theoretical, finite element analysis and experimental, approaches should be taken into account to assess stability due to different loading states, predict their behavior and consequently their effects on the dynamic response of structures, and understand complex behavior and properties of rubber-like materials respectively. In particular, the recent large-displacement theory on the stability of EB formulated by Forcellini and Kelly is validated with both numerical simulations using the finite element method, and experimental results set at the University of Antioquia in Medellin, Colombia. In this regard, this study reproduces the behavior of EB under compression loads and investigates the stability behavior with the three mentioned points of view.

Keywords: elastomeric bearings, experimental tests, numerical simulations, stability, large-displacement theory

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Authors: Abeer Ahmed Abdelhamed

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Introduction: Postoperative pulmonary complications (PPCs) are the most common complications observed and managed after abdominal or cardiothoracic surgery. Hypoxemia, atelectasis, pleural effusion, or diaphragmatic dysfunction, are often a source of morbidity in cardiac surgery patients, and are more common in patients receiving unilateral or bilateral internal mammary artery (IMT) grafts than patients receiving saphenous vein (SV) grafts alone. Purpose: The aim of this work was to investigate the effect of Threshold load inspiratory muscle training on pulmonary gas exchange and maximum inspiratory pressure (MIP) in patient undergoing coronary revascularization. Subject: Thirty three male patients eligible for coronary revascularization were selected to participate in the study. Method: They were divided into two groups(17 patients in the intervention group and 16 patients in the control group), the interventional group received inspiratory muscle training at 30% of their maximum inspiratory pressure throughout the hospitalization period in addition to routine post operative care. Result: The results of this study showed a significant improvement on maximum inspiratory pressure(MIP), Arterial-alveolar pressure gradient (A-a gradient) and oxygen saturation in the intervention group. Conclusion: Inspiratory muscle training using threshold mode significantly improves maximum inspiratory pressure, pulmonary gas exchange tested by alveolar-arterial gradient and oxygen saturation in Patients undergoing coronary revascularization.

Keywords: coronary revascularization, inspiratory muscle training, maximum inspiratory pressure, pulmonary gas exchange

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Authors: Hamed Khosravi, Reza Eslami-Farsani

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Increased interest in lightweight and efficient structural components has created the need for selecting materials with improved mechanical properties. To do so, composite materials are being widely used in many applications, due to durability, high strength and modulus, and low weight. Among the various composite structures, grid-stiffened structures are extensively considered in various aerospace and aircraft applications, because of higher specific strength and stiffness, higher impact resistance, superior load-bearing capacity, easy to repair, and excellent energy absorption capability. Although there are a good number of publications on the design aspects and fabrication of grid structures, little systematic work has been reported on their material modification to improve their properties, to our knowledge. Therefore, the aim of this research is to study the reinforcing effect of silica nanoparticles on the flexural properties of epoxy/E-glass isogrid panels under three-point bending test. Samples containing 0, 1, 3, and 5 wt.% of the silica nanoparticles, with 44 and 48 vol.% of the glass fibers in the ribs and skin components respectively, were fabricated by using a manual filament winding method. Ultrasonic and mechanical routes were employed to disperse the nanoparticles within the epoxy resin. To fabricate the ribs, the unidirectional fiber rovings were impregnated with the matrix mixture (epoxy + nanoparticles) and then laid up into the grooves of a silicone mold layer-by-layer. At once, four plies of woven fabrics, after impregnating into the same matrix mixture, were layered on the top of the ribs to produce the skin part. In order to conduct the ultimate curing and to achieve the maximum strength, the samples were tested after 7 days of holding at room temperature. According to load-displacement graphs, the bellow trend was observed for all of the samples when loaded from the skin side; following an initial linear region and reaching a load peak, the curve was abruptly dropped and then showed a typical absorbed energy region. It would be worth mentioning that in these structures, a considerable energy absorption was observed after the primary failure related to the load peak. The results showed that the flexural properties of the nanocomposite samples were always higher than those of the nanoparticle-free sample. The maximum enhancement in flexural maximum load and energy absorption was found to be for the incorporation of 3 wt.% of the nanoparticles. Furthermore, the flexural stiffness was continually increased by increasing the silica loading. In conclusion, this study suggested that the addition of nanoparticles is a promising method to improve the flexural properties of grid-stiffened fibrous composite structures.

Keywords: grid-stiffened composite structures, nanocomposite, three point flexural test , energy absorption

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Authors: Yiğit Gürler, Berkay Türkcan İmrağ, Taylan Güçkıran, İbrahim Şimşek, Alper Taşdemirci

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Paper honeycombs, which is a sandwich structure, consists of two liner faces and one paper honeycomb core. These materials are widely used in the packaging industry due to their low cost, low weight, good energy absorption capabilities and easy recycling properties. However, to provide maximum protection to the products in cases such as the drop of the packaged products, the mechanical behavior of these materials should be well known at the packaging design stage. In this study, the necessary input parameters for the modeling study were obtained by performing compression tests in the through-thickness and in-plane directions of paper-based honeycomb sandwich structures. With the obtained parameters, homogeneous and micro-mechanical numerical models were developed in the Ls-Dyna environment. The material card used for the homogeneous model is MAT_MODIFIED_HONEYCOMB, and the material card used for the micromechanical model is MAT_PIECEWISE_LINEAR_PLASTICITY. As a result, the effectiveness of homogeneous and micromechanical modeling approaches for paper-based honeycomb sandwich structure was investigated using force-displacement curves. Densification points and peak points on these curves will be compared.

Keywords: environmental packaging, mechanical characterization, Ls-Dyna, sandwich structure

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Authors: B. A. Parate, K. D. Deodhar, V. K. Dixit, V. V. Rao

Abstract:

This article outlines the ballistics of main seat ejection cartridges for aircraft application. The ballistics of main seat ejection cartridges plays a vital role during the ejection of the pilot in an emergency. The ballistic parameters such as maximum pressure, time is taken to reach the maximum pressure, and time required to reach half the maximum pressure contributes to the spinal injury of the pilot. Therefore, the evaluations of these parameters are very critical during various stages of development. Elaborate testing was carried out for main seat ejection cartridges on seat ejection tower (SET) at different operating temperatures considering physiological limits. As these trials are cumbersome in nature, a vented vessel (VV) testing facility was devised to lay down the performance parameters at hot and cold temperature conditions. Single base (SB) propellant having hepta-tubular configuration is selected as the main filling. Gun powder plays the role of a booster based on ballistic requirements. The evaluation methodology of various performance parameters of main seat ejection cartridges is explained in this paper. Physiological parameters such as maximum seat ejection velocity, acceleration, and rate of rising of acceleration are also experimentally determined on seat ejection tower. All the parameters are observed well within physiological limits. This paper addresses the internal ballistic of main seat ejection cartridges, propellant selection, its calculation, and evaluation of various performance parameters for an aircraft application.

Keywords: ballistics of seat ejection, ejection seat, gas generator, gun propulsion, main seat ejection cartridges, maximum pressure, performance parameters, propellant, progressive burning and vented vessel

Procedia PDF Downloads 128

Authors: Mawa Abdelbagi Mohamed Mohamed, Eslam Alaa Elbahlawan

Abstract:

This study examines the complex social fabric woven within the Abu-Shouk internally displaced persons camp, shaped by the chaotic waves of armed conflict and displacement in the early 2000s. The impact of war, economic constraints, and altered living conditions have fundamentally reshaped families and traditions, presenting both challenges and opportunities. In this exploration, we navigate the resilience of a community thrust into adversity, spotlighting how it emerged as essential in rebuilding social bonds. Exchanges of culture, intertribal marriages, and communal gathering spots have become essential tools in fostering cohesion and understanding amidst diversity. However, this resilience has been tested by the intrusion of politics, leading to shifts in governance structures and community dynamics. As we conclude, it is evident that while the scars of displacement and political disruptions are present, the community's enduring spirit and adaptability shine through. Empowering the community to rebuild their social tapestry, bridging the gaps, and restoring unity amid evolving political realities remain the beacon guiding their journey toward a shared, purposeful future.

Keywords: darfur, internally displaced person, social fabric, conflict

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Authors: Shield B. Lin, Ziraguen O. Williams

Abstract:

In a task to assist NASA in analyzing the dynamic forces caused by operational countermeasures of an astronaut’s exercise platform impacting the spacecraft, an active proportional-integral-derivative controller commanding a linear actuator is proposed in a vibration isolation system to regulate the movement of the exercise platform. Computer simulation shows promising results that most exciter forces can be reduced or even eliminated. This paper emphasizes on parameter uncertainties, variations and exciter force variations. Drift and variations of system parameters in the vibration isolation system for astronaut’s exercise platform are analyzed. An active controlled scheme is applied with the goals to reduce the platform displacement and to minimize the force being transmitted to the spacecraft structure. The controller must be robust enough to accommodate the wide variations of system parameters and exciter forces. Computer simulation for the vibration isolation system was performed via MATLAB/Simulink and Trick. The simulation results demonstrate the achievement of force reduction with small platform displacement under wide ranges of variations in system parameters.

Keywords: control, counterweight, isolation, vibration

Procedia PDF Downloads 117

Authors: Denise Muro

Abstract:

Conflict in Syria, producing over 11 million displaced persons, has incited global attention to displacement. Although neighboring countries have borne the largest part of the displacement burden, due to the influx of refugees into Europe, the so-called ‘refugee crisis’ is taking place on two fronts: Syria’s neighboring countries, with millions of refugees, and Europe, a destination goal for so many that European states face unprecedented challenges. With increasing attention to displacement, forcibly displaced persons are consistently portrayed as either un-agentic victims, or as dangerous free agents. Recognizing that these dominant portrayals involve discourses of power and inequality, this research investigates the extent to which this victim-agent dichotomy affects refugees and organizations that work closely with them during initial integration processes in Berlin, Germany. The research measures initial integration based on German policy measures regarding integration juxtaposed with the way refugees and those who work with them understand integration. Additionally, the study examines day-to-day interactions of refugees in Germany as a way to gauge social integration in a bottom-up approach. This study involved a discourse analysis of portrayals of refugees and participant observation and interviews with refugees and those who work closely with them, which took place during fieldwork in Berlin in the summer of 2016. Germany is unique regarding their migration history and lack of successful integration, in part due to the persistent refrain, ‘Wir sind kein einwanderungsland’ (‘We are not an immigration country’). Still, their accepted asylum seeker population has grown exponentially in the past few years. Findings suggest that the victim-agent dichotomy is present and impactful in the process of refugees entering and integrating into Germany. Integration is hindered due to refugees either being patronized or criminalized to such an extent that, despite being constantly told that they must integrate, they cannot become part of German society.

Keywords: discourse analysis, Germany, integration, refugee crisis

Procedia PDF Downloads 246

Authors: Tamou Nasser, Ahmed Essadki, Ali Boukhriss

Abstract:

This paper presents the control of doubly fed induction generator (DFIG) used in the wind energy conversion systems. Maximum power point tracking (MPPT) strategy is used to extract the maximum of power during the conversion and taking care that the system does not exceed the operating limits. This is done by acting on the pitch angle to control the orientation of the turbine's blades. Having regard to its robustness and performance, active disturbance rejection control (ADRC) based on the extended state observer (ESO) is employed to achieve the control of both rotor and grid side converters. Simulations are carried out using matlab simulink.

Keywords: active disturbance rejection control, extended state observer, doubly fed induction generator, maximum power point tracking

Procedia PDF Downloads 530

Authors: Tamou Nasser, Ahmed Essadki, Ali Boukhriss

Abstract:

This paper presents the control of doubly fed induction generator (DFIG) used in the wind energy conversion systems. Maximum power point tracking (MPPT) strategy is used to extract the maximum of power during the conversion and taking care that the system does not exceed the operating limits. This is done by acting on the pitch angle to control the orientation of the turbine's blades. Having regard to its robustness and performance, active disturbance rejection control (ADRC) based on the extended state observer (ESO) is employed to achieve the control of both rotor and grid side converters. Simulations are carried out using matlab simulink.

Keywords: active disturbance rejection control, extended state observer, doubly fed induction generator, maximum power point tracking

Procedia PDF Downloads 476

Authors: Sohail Ahmad, Inayat Kaleem

Abstract:

Federally Administered Tribal Area(FATA) of Pakistan is one of the most neglected regions in the world as far as development is concerned. It has been the hub of all sorts of illegal activities including militancy and export of terrorism. Therefore, it became inevitable for the government of Pakistan to take action against militants through military operations. Small and large scale military operations are being taken against the non-state actors in FATA with continuity. Over the years, hundreds of thousands have been displaced from the tribal areas of the country. Moreover, military operation Zarb-e-Azb has been launched in North Waziristan Agency in June 2014 to counter militancy across the Af-Pak border region. Though successful in curbing militancy, the operation has displaced around 0.5 million people from the area. Most of them opt to take shelter in the government installed shelter camps, some of them take refuge outside tent villages in the country while some of them prefer to cross into Afghanistan rather their own country Pakistan. This paper will evaluate how the influx of these internally displaced persons in the country is influencing the socio-economic situation of not only the displaced but of the hosting areas as well. Secondly, attention would be given to gauge the impact of such a huge number of displaced population on the law and order and security situation in the host areas.

Keywords: Af-Pak, federally administered tribal area, IDPs, internal displacement, Pakistan

Procedia PDF Downloads 292

Authors: Tamou Nasser, Ahmed Essadki, Ali Boukhriss

Abstract:

This paper presents the control of doubly fed induction generator (DFIG) used in the wind energy conversion systems. Maximum power point tracking (MPPT) strategy is used to extract the maximum of power during the conversion and taking care that the system does not exceed the operating limits. This is done by acting on the pitch angle to control the orientation of the turbine's blades. Having regard to its robustness and performance, active disturbance rejection control (ADRC) based on the extended state observer (ESO) is employed to achieve the control of both rotor and grid side converters. Simulations are carried out using MATLAB simulink.

Keywords: active disturbance rejection control, extended state observer, doubly fed induction generator, maximum power point tracking

Procedia PDF Downloads 503