Search results for: allowable load capacity
6047 Influence of Improved Roughage Quality and Period of Meal Termination on Digesta Load in the Digestive Organs of Goats
Authors: Rasheed A. Adebayo, Mehluli M. Moyo, Ignatius V. Nsahlai
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Ruminants are known to relish roughage for productivity but the effect of its quality on digesta load in rumen, omasum, abomasum and other distal organs of the digestive tract is yet unknown. Reticulorumen fill is a strong indicator for long-term control of intake in ruminants. As such, the measurement and prediction of digesta load in these compartments may be crucial to productivity in the ruminant industry. The current study aimed at determining the effect of (a) diet quality on digesta load in digestive organs of goats, and (b) period of meal termination on the reticulorumen fill and digesta load in other distal compartments of the digestive tract of goats. Goats were fed with urea-treated hay (UTH), urea-sprayed hay (USH) and non-treated hay (NTH). At the end of eight weeks of a feeding trial period, upon termination of a meal in the morning, afternoon or evening, all goats were slaughtered in random groups of three per day to measure reticulorumen fill and digesta loads in other distal compartments of the digestive tract. Both diet quality and period affected (P < 0.05) the measure of reticulorumen fill. However, reticulorumen fill in the evening was larger (P < 0.05) than afternoon, while afternoon was similar (P > 0.05) to morning. Also, diet quality affected (P < 0.05) the wet omasal digesta load, wet abomasum, dry abomasum and dry caecum digesta loads but did not affect (P > 0.05) both wet and dry digesta loads in other compartments of the digestive tract. Period of measurement did not affect (P > 0.05) the wet omasal digesta load, and both wet and dry digesta loads in other compartments of the digestive tract except wet abomasum digesta load (P < 0.05) and dry caecum digesta load (P < 0.05). Both wet and dry reticulorumen fill were correlated (P < 0.05) with omasum (r = 0.623) and (r = 0.723), respectively. In conclusion, reticulorumen fill of goats decreased by improving the roughage quality; and the period of meal termination and measurement of the fill is a key factor to the quantity of digesta load.Keywords: digesta, goats, meal termination, reticulo-rumen fill
Procedia PDF Downloads 3656046 Improving Cyclability and Capacity of Lithium Oxygen Batteries via Low Rate Pre-Activation
Authors: Zhihong Luo, Guangbin Zhu, Lulu Guo, Zhujun Lyu, Kun Luo
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Cycling life has become the threshold for the prospective application of Li-O₂ batteries, and the protection of Li anode has recently regarded as the key factor to the performance. Herein, a simple low rate pre-activation (20 cycles at 0.5 Ag⁻¹ and a capacity of 200 mAh g⁻¹) was employed to effectively improve the performance and cyclability of Li-O₂ batteries. The charge/discharge cycles at 1 A g⁻¹ with a capacity of 1000 mAh g⁻¹ were maintained for up to 290 times versus 55 times for the cell without pre-activation. The ultimate battery capacity and high rate discharge property were also largely enhanced. Morphology, XRD and XPS analyses reveal that the performance improvement is in close association with the formation of the smooth and compact surface layer formed on the Li anode after low rate pre-activation, which apparently alleviated the corrosion of Li anode and the passivation of cathode during battery cycling, and the corresponding mechanism was also discussed.Keywords: lithium oxygen battery, pre-activation, cyclability, capacity
Procedia PDF Downloads 1506045 Parametric Study and Design on under Reamed Pile - An Experimental and Numerical Study
Authors: S. Chandrakaran, Aarthy D.
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Abstract: Under reamed piles are piles which are of different types like bored cast in-situ pile or bored compaction concrete piles where one or more bulbs are provided. In this paper, the design procedure of under reamed pile by both experimental study and numerical study using PLAXIS 3D Foundation software was studied. The soil chosen for study was M Sand. The Single and double under reamed pile modelling was made using mild steel. The pile load test experiment was conducted in the laboratory and the ultimate compression load for 25 mm settlement on single and double under reamed pile was observed and finally the result was compared with conventional pile (pile without bulb). The parametric influence on under reamed pile was studied by varying the geometrical parameters like diameter of bulbs, spacing between bulbs, position of bulbs and number of bulbs. The results of the numerical model showed that when the diameter of bulb D u =2.5D, the ultimate compression load for an under-reamed pile with a single bulb increased by 55 % compared to a pile without a bulb. It was observed that when the spacing between the bulbs was S=6D u with three different positions of bulb from bottom of pile as D u , 2D u and 3D u , the ultimate compression load increased by 88%, 94% and 73 % respectively, compared to the ultimate compression load for 25 mm settlement on conventional pile and if spacing was more than 6D u , ultimate compression load for 25 mm settlement started to decrease. It was observed that when the bucket length was more than 2D u , the ultimate compressionKeywords: load capcity, under remed bulb . sand, model study, sand
Procedia PDF Downloads 776044 Analysis of Tilting Cause of a Residential Building in Durres by the Use of Cptu Test
Authors: Neritan Shkodrani
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On November 26, 2019, an earthquake hit the central western part of Albania. It was assessed as Mw 6.4. Its epicenter was located offshore north western Durrës, about 7 km north of the city. In this paper, the consequences of settlements of very soft soils have been discussed for the case of a residential building, mentioned as “K Building”, which was suffering a significant tilting after the earthquake. “KBuilding” is an RC framed building having 12+1 (basement) storiesand a floor area of 21000 m2. The construction of the building was completed in 2012. “KBuilding”, located in Durres city, suffered severe non-structural damage during November 26, 2019, Durrës Earthquake sequences. During the in-site inspections immediately after the earthquake, the general condition of the buildings, the presence of observable settlements on the ground, and the crack situation in the structure were determined, and damage inspection were performed. It was significant to note that the “K Building” presented tilting that might be attributed, as it was believed at the beginning, partially to the failure of the columns of the ground floor and partially to liquefaction phenomena, but it did not collapse. At the first moment was not clear if the foundation had a bearing capacity failure or the foundation failed because of the soil liquefaction. Geotechnical soil investigations by using CPTU test were executed, and their data are usedto evaluatebearing capacity, consolidation settlement of the mat foundation, and soil liquefaction since they were believed to be the main reasons of this building tilting.Geotechnical soil investigation consist in 5 (five) Static Cone Penetration tests with pore pressure measurement (piezocone test). They reached a penetration depth of 20.0 m to 30.0 mand, clearly shown the presence of very soft and organic soils in the soil profile of the site. Geotechnical CPT based analysis of bearing capacity, consolidation, and secondary settlement are applied, and results are reported for each test. These results shown very small values of allowable bearing capacity and very high values of consolidation and secondary settlements. Liquefaction analysis based on the data of CPTU tests and the characteristics of ground shaking of the mentioned earthquake has shown the possibility of liquefaction for some layers of the considered soil profile, but the estimated vertical settlements are at a small range and clearly shown that the main reason of the building tilting was not related to the consequences of liquefaction, but was an existing settlement caused from the applied bearing pressure of this building. All the CPTU tests were carried out on August 2021, almost two years after the November 26, 2019, Durrës Earthquake and when the building itself was demolished. After removing the mat foundation on September 2021, it was possible to carry out CPTU tests even on the footprint of the existing building, which made possible to observe the effects of long time applied of foundation bearing pressure to the consolidation on the considered soil profile.Keywords: bearing capacity, cone penetration test, consolidation settlement, secondary settlement, soil liquefaction, etc
Procedia PDF Downloads 926043 Flexural Behavior of Voided Slabs Reinforced With Basalt Bars
Authors: Jazlah Majeed Sulaiman, Lakshmi P.
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Concrete slabs are considered to be very ductile structural members. Openings in reinforced slabs are necessary so as to install the mechanical, electrical and pumping (MEP) conduits and ducts. However, these openings reduce the load-carrying capacity, stiffness, energy, and ductility of the slabs. To resolve the undesirable effects of openings in the slab behavior, it is significant to achieve the desired strength against the loads acting on it. The use of Basalt Fiber Reinforcement Polymers (BFRP) as reinforcement has become a valid sustainable option as they produce less greenhouse gases, resist corrosion and have higher tensile strength. In this paper, five slab models are analyzed using non-linear static analysis in ANSYS Workbench to study the effect of openings on slabs reinforced with basalt bars. A parametric numerical study on the loading condition and the shape and size of the opening is conducted, and their load and displacement values are compared. One of the models is validated experimentally.Keywords: concrete slabs, openings, BFRP, sustainable, corrosion resistant, non-linear static analysis, ANSYS
Procedia PDF Downloads 1026042 Application of Ground Penetrating Radar and Light Falling Weight Deflectometer in Ballast Quality Assessment
Authors: S. Cafiso, B. Capace, A. Di Graziano, C. D’Agostino
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Systematic monitoring of the trackbed is necessary to assure safety and quality of service in the railway system. Moreover, to produce effective management of the maintenance treatments, the assessment of bearing capacity of the railway trackbed must include ballast, sub-ballast and subgrade layers at different depths. Consequently, there is an increasing interest in obtaining a consistent measure of ballast bearing capacity with no destructive tests (NDTs) able to work in the physical and time restrictions of railway tracks in operation. Moreover, in the case of the local railway with reduced gauge, the use of the traditional high-speed track monitoring systems is not feasible. In that framework, this paper presents results from in site investigation carried out on ballast and sleepers with Ground Penetrating Radar (GPR) and Light Falling Weight Deflectometer (LWD). These equipment are currently used in road pavement maintenance where they have shown their reliability and effectiveness. Application of such Non-Destructive Tests in railway maintenance is promising but in the early stage of the investigation. More specifically, LWD was used to estimate the stiffness of ballast and sleeper support, as well. LWD, despite the limited load (6 kN in the trial test) applied directly on the sleeper, was able to detect defects in the bearing capacity at the Sleeper/Ballast interface. A dual frequency GPR was applied to detect the presence of layers’ discontinuities at different depths due to fouling phenomena that are the main causes of changing in the layer dielectric proprieties within the ballast thickness. The frequency of 2000Mhz provided high-resolution data to approximately 0.4m depth, while frequency of 600Mhz showed greater depth penetration up to 1.5 m. In the paper literature review and trial in site experience are used to identify Strengths, Weaknesses, Opportunities, and Threats (SWOT analysis) of the application of GPR and LWD for the assessment of bearing capacity of railway track-bed.Keywords: bearing capacity, GPR, LWD, no destructive test, railway track
Procedia PDF Downloads 1246041 Effect of Elastic Modulus Anisotropy on Helical Piles Behavior in Sandy Soil
Authors: Reza Ziaie Moayed, Javad Shamsi Soosahab
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Helical piles are being used extensively in engineering applications all over the world. There are insufficient studies on the helical piles' behavior in anisotropic soils. In this paper, numerical modeling was adopted to investigate the effect of elastic modulus anisotropy on helical pile behavior resting on anisotropic sand by using a finite element limit analysis. The load-displacement behavior of helical piles under compression and tension loads is investigated in different relative densities of soils, and the effect of the ratio of horizontal elastic modulus with respect to vertical elastic modulus (EH/EV) is evaluated. The obtained results illustrate that in sandy soils, the anisotropic ratio of elastic modulus (EH/EV) has notable effect on bearing capacity of helical piles in different relative density. Therefore, it may be recommended that the effect of anisotropic condition of soil elastic modulus should be considered in helical piles behavior.Keywords: helical piles, bearing capacity, numerical modeling, soil anisotropy
Procedia PDF Downloads 1576040 Pull-Out Behavior of Mechanical Anchor Bolts by Cyclic Loading
Authors: Yoshinori Kitsutaka, Kusumi Shingo, Matsuzawa Koichi, Kunieda Yoichiro, Yagisawa Yasuei
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In this study, the pull-out properties of various mechanical anchor bolts embedded in concrete were investigated. Five kinds of mechanical anchor bolts were selected which were ordinarily used for concrete anchoring. Tensile tests for mechanical anchor bolts embedded in φ300mm x 100mm size concrete were conducted to measure the load - load displacement curves. The loading conditions were a monotonous loading and a repeating loading. The fracture energy for each mechanical anchor bolts was estimated by the analysis of consumed energy calculated by the load - load displacement curve. The effect of the types of mechanical anchor bolts on the pull-out properties of concrete subjected in monotonous loading and a repeating loading was cleared.Keywords: concrete, cyclic loading, mechanical anchor bolt, pull-out strength
Procedia PDF Downloads 2546039 Structural Behavior of Composite Hollow RC Column under Combined Loads
Authors: Abdul Qader Melhm, Hussein Elrafidi
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This paper is dealing with studying the structural behavior of a steel-composite hollow reinforced concrete (RC) column model under combined eccentric loading. The composite model consists of an inner steel tube surrounded via a concrete core with longitudinal and circular transverse reinforcement. The radius of gyration according to American and Euro specifications be calculated, in order to calculate the thinnest ratio for this type of composite column model, in addition to the flexural rigidity. Formulas for interaction diagram is given for this type of model, which is a general loading conditions in which an element is exposed to an axial load with bending at the same time. The structural capacity of this model, elastic, plastic loads and strains will be computed and compared with experimental results. The total eccentric axial load of the column model is calculated based on the effective length KL available from several relationships provided in the paper. Furthermore, the inner tube experiences buckling failure after reaching its maximum strength will be investigated.Keywords: column, composite, eccentric, inner tube, interaction, reinforcement
Procedia PDF Downloads 1876038 Frequency Controller Design for Distributed Generation by Load Shedding: Multi-Agent Systems Approach
Authors: M. R. Vaezi, R. Ghasemi, A. Akramizadeh
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Frequency stability of microgrids under islanded operation attracts particular attention recently. A new cooperative frequency control strategy based on centralized multi-agent system (CMAS) is proposed in this study. On this strategy, agents sent data and furthermore each component has its own to center operating decisions (MGCC). After deciding on the information, they are returned. Frequency control strategies include primary and secondary frequency control and disposal of multi-stage load in which this study will also provide a method and algorithm for load shedding. This could also be a big problem for the performance of micro-grid in times of disaster. The simulation results show the promising performance of the proposed structure of the controller based on multi agent systems.Keywords: frequency control, islanded microgrid, multi-agent system, load shedding
Procedia PDF Downloads 4576037 Comparison of Various Response Spectrum of Nuclear Power Plant at Chashma Site
Authors: J. Iqbal, A. Shah, M. Zeeshan
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UBC-97, USNRC, chines origin code GB50011-2011 and site response spectrum was used to make comparison between them for Chashma site and most conservative one was selected and the USNRC was the most conservative one. The dynamic analysis of CHASNUPP-2 containment building was performed using SAP-2000 for dead load, live load (crane), pre stressed loads, wind load, temperature load, accidental pressure during LOCA, earthquake loads and the conservative response spectrum. After applying selected response spectrum on model, detail comparison was made against area of steal calculated from the analysis and the actually provided. Then prepared curve of area of steal vs. g value which shows that if the particular site was design on that spectrum that much steel needed for structural integrity.Keywords: response spectrum, USNRC, LOCA, area of steel, structure integrity
Procedia PDF Downloads 6736036 Voltage Stabilization of Hybrid PV and Battery Systems by Considering Temperature and Irradiance Changes in Standalone Operation
Authors: S. Jalilzadeh, S. M. Mohseni Bonab
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Solar and battery energy storage systems are very useful for consumers who live in deprived areas and do not have access to electricity distribution networks. Nowadays one of the problems that photo voltaic systems (PV) have changing of output power in temperature and irradiance variations, which directly affects the load that is connected to photo voltaic systems. In this paper, with considering the fact that the solar array varies with change in temperature and solar power radiation, a voltage stabilizer system of a load connected to photo voltaic array is designed to stabilize the load voltage and to transfer surplus power of the battery. Also, in proposed hybrid system, the needed load power amount is supplemented considering the voltage stabilization in standalone operation for supplying unbalanced AC load. Electrical energy storage system for voltage control and improvement of the performance of PV by a DC/DC converter is connected to the DC bus. The load is also feed by an AC/DC converter. In this paper, when the voltage increases in its reference limit, the battery gets charged by the photo voltaic array and when it decreases in its defined limit, the power gets injected to the DC bus by this battery. The constant of DC bus Voltage is the cause for the reduced harmonics generated by the inverter. In addition, a series of filters are provided in the inverter output in to reduced harmonics. The inverter control circuit is designed that the voltage and frequency of the load remain almost constant at different load conditions. This paper has focused on controlling strategies of converters to improve their performance.Keywords: photovoltaic array (PV), DC/DC Boost converter, battery converter, inverters control
Procedia PDF Downloads 4816035 The Relationship between Absorptive Capacity and Green Innovation
Authors: R. Hashim, A. J. Bock, S. Cooper
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Absorptive capacity generally facilitates the adoption of innovation. How does this relationship change when economic return is not the sole driver of innovation uptake? We investigate whether absorptive capacity facilitates the adoption of green innovation based on a survey of 79 construction companies in Scotland. Based on the results of multiple regression analyses, we confirm that existing knowledge utilisation (EKU), knowledge building (KB) and external knowledge acquisition (EKA) are significant predictors of green process GP), green administrative (GA) and green technical innovation (GT), respectively. We discuss the implications for theories of innovation adoption and knowledge enhancement associated with environmentally-friendly practices.Keywords: absorptive capacity, construction industry, environmental, green innovation
Procedia PDF Downloads 5186034 Comparison of ANN and Finite Element Model for the Prediction of Ultimate Load of Thin-Walled Steel Perforated Sections in Compression
Authors: Zhi-Jun Lu, Qi Lu, Meng Wu, Qian Xiang, Jun Gu
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The analysis of perforated steel members is a 3D problem in nature, therefore the traditional analytical expressions for the ultimate load of thin-walled steel sections cannot be used for the perforated steel member design. In this study, finite element method (FEM) and artificial neural network (ANN) were used to simulate the process of stub column tests based on specific codes. Results show that compared with those of the FEM model, the ultimate load predictions obtained from ANN technique were much closer to those obtained from the physical experiments. The ANN model for the solving the hard problem of complex steel perforated sections is very promising.Keywords: artificial neural network (ANN), finite element method (FEM), perforated sections, thin-walled Steel, ultimate load
Procedia PDF Downloads 3446033 The Effects of Time and Cyclic Loading to the Axial Capacity for Offshore Pile in Shallow Gas
Authors: Christian H. Girsang, M. Razi B. Mansoor, Noorizal N. Huang
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An offshore platform was installed in 1977 at about 260km offshore West Malaysia at the water depth of 73.6m. Twelve (12) piles were installed with four (4) are skirt piles. The piles have 1.219m outside diameter and wall thickness of 31mm and were driven to 109m below seabed. Deterministic analyses of the pile capacity under axial loading were conducted using the current API (American Petroleum Institute) method and the four (4) CPT-based methods: the ICP (Imperial College Pile)-method, the NGI (Norwegian Geotechnical Institute)-Method, the UWA (University of Western Australia)-method and the Fugro-method. A statistical analysis of the model uncertainty associated with each pile capacity method was performed. There were two (2) piles analysed: Pile 1 and piles other than Pile 1, where Pile 1 is the pile that was most affected by shallow gas problems. Using the mean estimate of soil properties, the five (5) methods used for deterministic estimation of axial pile capacity in compression predict an axial capacity from 28 to 42MN for Pile 1 and 32 to 49MN for piles other than Pile 1. These values refer to the static capacity shortly after pile installation. They do not include the effects of cyclic loading during the design storm or time after installation on the axial pile capacity. On average, the axial pile capacity is expected to have increased by about 40% because of ageing since the installation of the platform in 1977. On the other hand, the cyclic loading effects during the design storm may reduce the axial capacity of the piles by around 25%. The study concluded that all piles have sufficient safety factor when the pile aging and cyclic loading effect are considered, as all safety factors are above 2.0 for maximum operating and storm loads.Keywords: axial capacity, cyclic loading, pile ageing, shallow gas
Procedia PDF Downloads 3346032 The Behavior of Masonry Wall Constructed Using Biaxial Interlocking Concrete Block, Solid Concrete Block and Cement Sand Brick Subjected to the Compressive Load
Authors: Fauziah Aziz, Mohd.fadzil Arshad, Hazrina Mansor, Sedat Kömürcü
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Masonry is an isotropic and heterogeneous material due to the presence of the different components within the assembly process. Normally the mortar plays a significant role in the compressive behavior of the traditional masonry structures. Biaxial interlocking concrete block is a masonry unit that comes out with the interlocking concept. This masonry unit can improve the quality of the construction process, reduce the cost of labor, reduce high skill workmanship, and speeding the construction time. Normally, the interlocking concrete block masonry unit in the market place was designed in a way interlocking concept only either x or y-axis, shorter in length, and low compressive strength value. However, the biaxial interlocking concrete block is a dry-stack concept being introduced in this research, offered the specialty compared to the normal interlocking concrete available in the market place due to its length and the geometry of the groove and tongue. This material can be used as a non-load bearing wall, or load-bearing wall depends on the application of the masonry. But, there is a lack of technical data that was produced before. This paper presents a finding on the compressive resistance of the biaxial interlocking concrete block masonry wall compared to the other traditional masonry walls. Two series of biaxial interlocking concrete block masonry walls, namely M1 and M2, a series of solid concrete block and cement sand brick walls M3, and M4 have tested the compressive resistance. M1 is the masonry wall of a hollow biaxial interlocking concrete block meanwhile; M2 is the grouted masonry wall, M3 is a solid concrete block masonry wall, and M4 is a cement sand brick masonry wall. All the samples were tested under static compressive load. The results examine that M2 is higher in compressive resistance compared to the M1, M3, and M4. It shows that the compressive strength of the concrete masonry units plays a significant role in the capacity of the masonry wall.Keywords: interlocking concrete block, compressive resistance, concrete masonry unit, masonry
Procedia PDF Downloads 1616031 Optimization of Hybrid off Grid Energy Station
Authors: Yehya Abdellatif, Iyad M. Muslih, Azzah Alkhalailah, Abdallah Muslih
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Hybrid Optimization Model for Electric Renewable (HOMER) software was utilized to find the optimum design of a hybrid off-Grid system, by choosing the optimal solution depending on the cost analysis of energy based on different capacity shortage percentages. A complete study for the site conditions and load profile was done to optimize the design and implementation of a hybrid off-grid power station. In addition, the solution takes into consecration the ambient temperature effect on the efficiency of the power generation and the economical aspects of selection depending on real market price. From the analysis of the HOMER model results, the optimum hybrid power station was suggested, based on wind speed, and solar conditions. The optimization function objective is to minimize the Net Price Cost (NPC) and the Cost of Energy (COE) with zero and 10 percentage of capacity shortage.Keywords: energy modeling, HOMER, off-grid system, optimization
Procedia PDF Downloads 5606030 Multi-Objective Optimization of Wear Parameters of Tube Like Clay Mineral Filled Thermoplastic Polymer Using Response Surface Methodology
Authors: Vasu Velagapudi, G. Suresh
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PTFE/HNTs nanocomposites are fabricated with 4%, 6%, and 8% by weight fraction, and the optimization study of wear parameters are performed using response surface methodology (RSM). The experiments are carried out on a pin on disc (POD) wear tester under different operating parameters planned according to Taguchi L27 orthogonal array. The input factors considered are wt% HNTs addition, sliding velocity, load, and distance with three levels for each factor. From ANOVA: The factors load, speed and distance and their interactions have a significant effect on COF. Also for SWR, composition factor and interaction of load and speed are observed to be significant ( < 0.05) Optimum input parameters corresponding to desirability 1 are found to be: COF (0.11) and SWR (17.5)×10⁻⁶ (mm3/N-m) at 6.34 wt% of composition, 5N of load, 2 km of distance and 1 m/sec of velocity.Keywords: PTFE/HNT, nanocomposites, response surface methodology (RSM), specific wear rate
Procedia PDF Downloads 3926029 Sustainable Upgrade of Existing Heritage Infrastructure - Strengthening and Rehabilitation of The LH Ford Bridge
Authors: Vince Scolaro, Lakshman Prasad, Ted Polley, Sanjivan Deshpande
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The LH Ford Bridge, built in the 1960s, comprises 28 spans, is 800m long and crosses the Macquarie River at Dubbo, NSW. The main bridge spans comprise three spans with a 63m center span (25m drop-in section) supported by halving joints from the main cantilevers and back spans of 28m. The main bridge spans were built using complex construction staging (the first of this type in NSW). They comprise twin precast boxes, in-situ reinforced concrete infills, and cantilevered outriggers stressed both longitudinally and transversely. Since construction, this bridge has undergone significantly increased design vehicle loads and showed signs of excessive shrinkage and creep leading to significant sagging of the centre span with evidence of previous failure and remediation of the halving joints. A comprehensive load rating assessment was undertaken taking account of the original complex construction staging. Deficiencies identified included inadequate capacity of the halving joints, failure of the bearings at the halving joints, inadequate shear capacity of the girder webs and inadequate girder flexural capacity to carry B-Double design vehicles. A unique strengthening system comprising two new piers (under each of the halving joints), new bearings and installation of external prestressing to the soffit of both drop-in-span and back spans was adopted. A portion of the dead load had to be transferred from the superstructure to the new piers via innovative soft/stiff bearing combinations to reduce new locked-in stresses resulting from the new pier supports. Significant temporary works comprised a precast concrete shell beam forming the pile cap/pier structure, addition of a temporary suspended scaffold (without overstressing the existing superstructure) and the installation of jacking stays for new bearing top and bottom plates. This paper presents how this existing historic and socially important bridge was strengthened and updated to increase its design life without the need for replacement.Keywords: strengthening, creep, construction, box girder
Procedia PDF Downloads 1316028 Impact Study on a Load Rich Island and Development of Frequency Based Auto-Load Shedding Scheme to Improve Service Reliability of the Island
Authors: Md. Shafiullah, M. Shafiul Alam, Bandar Suliman Alsharif
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Electrical quantities such as frequency, voltage, current are being fluctuated due to abnormalities in power system. Most of the abnormalities cause fluctuation in system frequency and sometimes extreme abnormalities lead to system blackout. To protect the system from complete blackout planned and proper islanding plays a very important role even in case of extreme abnormalities. Islanding operation not only helps stabilizing a faulted system but also supports power supplies to critical and important loads, in extreme emergency. But the islanding systems are weaker than integrated system so the stability of islands is the prime concern when an integrated system is disintegrated. In this paper, different impacts on a load rich island have been studied and a frequency based auto-load shedding scheme has been developed for sudden load addition, generation outage and combined effect of both to the island. The developed scheme has been applied to Khulna-Barisal Island to validate the effectiveness of the developed technique. Various types of abnormalities to the test system have been simulated and for the simulation purpose CYME PSAF (Power System Analysis Framework) has been used.Keywords: auto load shedding, FS&FD relay, impact study, island, PSAF, ROCOF
Procedia PDF Downloads 4506027 Operation Strategy of Multi-Energy Storage System Considering Power System Reliability
Authors: Wook-Won Kim, Je-Seok Shin, Jin-O Kim
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As the penetration of Energy Storage System (ESS) increases in the power system due to higher performance and lower cost than ever, ESS is expanding its role to the ancillary service as well as the storage of extra energy from the intermittent renewable energy resources. For multi-ESS with different capacity and SOC level each other, it is required to make the optimal schedule of SOC level use the multi-ESS effectively. This paper proposes the energy allocation method for the multiple battery ESS with reliability constraint, in order to make the ESS discharge the required energy as long as possible. A simple but effective method is proposed in this paper, to satisfy the power for the spinning reserve requirement while improving the system reliability. Modelling of ESS is also proposed, and reliability is evaluated by using the combined reliability model which includes the proposed ESS model and conventional generation one. In the case study, it can be observed that the required power is distributed to each ESS adequately and accordingly, the SOC is scheduled to improve the reliability indices such as Loss of Load Probability (LOLP) and Loss of Load Expectation (LOLE).Keywords: multiple energy storage system (MESS), energy allocation method, SOC schedule, reliability constraints
Procedia PDF Downloads 3606026 Tuning of the Thermal Capacity of an Envelope for Peak Demand Reduction
Authors: Isha Rathore, Peeyush Jain, Elangovan Rajasekar
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The thermal capacity of the envelope impacts the cooling and heating demand of a building and modulates the peak electricity demand. This paper presents the thermal capacity tuning of a building envelope to minimize peak electricity demand for space cooling. We consider a 40 m² residential testbed located in Hyderabad, India (Composite Climate). An EnergyPlus model is validated using real-time data. A Parametric simulation framework for thermal capacity tuning is created using the Honeybee plugin. Diffusivity, Thickness, layer position, orientation and fenestration size of the exterior envelope are parametrized considering a five-layered wall system. A total of 1824 parametric runs are performed and the optimum wall configuration leading to minimum peak cooling demand is presented.Keywords: thermal capacity, tuning, peak demand reduction, parametric analysis
Procedia PDF Downloads 1766025 Capacity Optimization in Cooperative Cognitive Radio Networks
Authors: Mahdi Pirmoradian, Olayinka Adigun, Christos Politis
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Cooperative spectrum sensing is a crucial challenge in cognitive radio networks. Cooperative sensing can increase the reliability of spectrum hole detection, optimize sensing time and reduce delay in cooperative networks. In this paper, an efficient central capacity optimization algorithm is proposed to minimize cooperative sensing time in a homogenous sensor network using OR decision rule subject to the detection and false alarm probabilities constraints. The evaluation results reveal significant improvement in the sensing time and normalized capacity of the cognitive sensors.Keywords: cooperative networks, normalized capacity, sensing time
Procedia PDF Downloads 6256024 Effect of Load Ratio on Probability Distribution of Fatigue Crack Propagation Life in Magnesium Alloys
Authors: Seon Soon Choi
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It is necessary to predict a fatigue crack propagation life for estimation of structural integrity. Because of an uncertainty and a randomness of a structural behavior, it is also required to analyze stochastic characteristics of the fatigue crack propagation life at a specified fatigue crack size. The essential purpose of this study is to present the good probability distribution fit for the fatigue crack propagation life at a specified fatigue crack size in magnesium alloys under various fatigue load ratio conditions. To investigate a stochastic crack growth behavior, fatigue crack propagation experiments are performed in laboratory air under several conditions of fatigue load ratio using AZ31. By Anderson-Darling test, a goodness-of-fit test for probability distribution of the fatigue crack propagation life is performed and the good probability distribution fit for the fatigue crack propagation life is presented. The effect of load ratio on variability of fatigue crack propagation life is also investigated.Keywords: fatigue crack propagation life, load ratio, magnesium alloys, probability distribution
Procedia PDF Downloads 6416023 Hierarchical Queue-Based Task Scheduling with CloudSim
Authors: Wanqing You, Kai Qian, Ying Qian
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The concepts of Cloud Computing provide users with infrastructure, platform and software as service, which make those services more accessible for people via Internet. To better analysis the performance of Cloud Computing provisioning policies as well as resources allocation strategies, a toolkit named CloudSim proposed. With CloudSim, the Cloud Computing environment can be easily constructed by modelling and simulating cloud computing components, such as datacenter, host, and virtual machine. A good scheduling strategy is the key to achieve the load balancing among different machines as well as to improve the utilization of basic resources. Recently, the existing scheduling algorithms may work well in some presumptive cases in a single machine; however they are unable to make the best decision for the unforeseen future. In real world scenario, there would be numbers of tasks as well as several virtual machines working in parallel. Based on the concepts of multi-queue, this paper presents a new scheduling algorithm to schedule tasks with CloudSim by taking into account several parameters, the machines’ capacity, the priority of tasks and the history log.Keywords: hierarchical queue, load balancing, CloudSim, information technology
Procedia PDF Downloads 4156022 The Impact of Cognitive Load on Deceit Detection and Memory Recall in Children’s Interviews: A Meta-Analysis
Authors: Sevilay Çankaya
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The detection of deception in children’s interviews is essential for statement veracity. The widely used method for deception detection is building cognitive load, which is the logic of the cognitive interview (CI), and its effectiveness for adults is approved. This meta-analysis delves into the effectiveness of inducing cognitive load as a means of enhancing veracity detection during interviews with children. Additionally, the effectiveness of cognitive load on children's total number of events recalled is assessed as a second part of the analysis. The current meta-analysis includes ten effect sizes from search using databases. For the effect size calculation, Hedge’s g was used with a random effect model by using CMA version 2. Heterogeneity analysis was conducted to detect potential moderators. The overall result indicated that cognitive load had no significant effect on veracity outcomes (g =0.052, 95% CI [-.006,1.25]). However, a high level of heterogeneity was found (I² = 92%). Age, participants’ characteristics, interview setting, and characteristics of the interviewer were coded as possible moderators to explain variance. Age was significant moderator (β = .021; p = .03, R2 = 75%) but the analysis did not reveal statistically significant effects for other potential moderators: participants’ characteristics (Q = 0.106, df = 1, p = .744), interview setting (Q = 2.04, df = 1, p = .154), and characteristics of interviewer (Q = 2.96, df = 1, p = .086). For the second outcome, the total number of events recalled, the overall effect was significant (g =4.121, 95% CI [2.256,5.985]). The cognitive load was effective in total recalled events when interviewing with children. All in all, while age plays a crucial role in determining the impact of cognitive load on veracity, the surrounding context, interviewer attributes, and inherent participant traits may not significantly alter the relationship. These findings throw light on the need for more focused, age-specific methods when using cognitive load measures. It may be possible to improve the precision and dependability of deceit detection in children's interviews with the help of more studies in this field.Keywords: deceit detection, cognitive load, memory recall, children interviews, meta-analysis
Procedia PDF Downloads 516021 Solar Powered Front Wheel Drive (FWD) Electric Trike: An Innovation
Authors: Michael C. Barbecho, Romeo B. Morcilla
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This study focused on the development of a solar powered front wheel drive electric trike for personal use and short distance travel, utilizing solar power and a variable speed transmission to adapt in places where varying road grades and unavailability of plug-in charging stations are of great problems. The actual performance of the vehicle was measured in terms of duration of charging using solar power, distance travel and battery power duration, top speed developed at full power, and load capacity. This project followed the research and development process which involved planning, designing, construction, and testing. Solar charging tests revealed that the vehicle requires 6 to 8 hours sunlight exposure to fully charge the batteries. At full charge, the vehicle can travel 35 km utilizing battery power down to 42%. Vehicle showed top speed of 25 kph at 0 to 3% road grade carrying a maximum load of 122 kg. The maximum climbing grade was 23% with the vehicle carrying a maximum load of 122 kg. Technically the project was feasible and can be a potential model for possible conversion of traditional Philippine made “pedicabs” and gasoline engine powered tricycle into modern electric vehicles. Moreover, it has several technical features and advantages over a commercialized electric vehicle such as the use solar charging system and variable speed power transmission and front drive power train for adaptability in any road gradient.Keywords: electric vehicle, solar vehicles, front drive, solar, solar power
Procedia PDF Downloads 5676020 Estimation of Probabilistic Fatigue Crack Propagation Models of AZ31 Magnesium Alloys under Various Load Ratio Conditions by Using the Interpolation of a Random Variable
Authors: Seon Soon Choi
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The essential purpose is to present the good fatigue crack propagation model describing a stochastic fatigue crack growth behavior in a rolled magnesium alloy, AZ31, under various load ratio conditions. Fatigue crack propagation experiments were carried out in laboratory air under four conditions of load ratio, R, using AZ31 to investigate the crack growth behavior. The stochastic fatigue crack growth behavior was analyzed using an interpolation of random variable, Z, introduced to an empirical fatigue crack propagation model. The empirical fatigue models used in this study are Paris-Erdogan model, Walker model, Forman model, and modified Forman model. It was found that the random variable is useful in describing the stochastic fatigue crack growth behaviors under various load ratio conditions. The good probabilistic model describing a stochastic fatigue crack growth behavior under various load ratio conditions was also proposed.Keywords: magnesium alloys, fatigue crack propagation model, load ratio, interpolation of random variable
Procedia PDF Downloads 4076019 Load Transfer of Steel Pipe Piles in Warming Permafrost
Authors: S. Amirhossein Tabatabaei, Abdulghader A. Aldaeef, Mohammad T. Rayhani
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As the permafrost continues to melt in the northern regions due to global warming, a soil-water mixture is left behind with drastically lower strength; a phenomenon that directly impacts the resilience of existing structures and infrastructure systems. The frozen soil-structure interaction, which in ice-poor soils is controlled by both interface shear and ice-bonding, changes its nature into a sole frictional state. Adfreeze, the controlling mechanism in frozen soil-structure interaction, diminishes as the ground temperature approaches zero. The main purpose of this paper is to capture the altered behaviour of frozen interface with respect to rising temperature, especially near melting states. A series of pull-out tests are conducted on model piles inside a cold room to study how the strength parameters are influenced by the phase change in ice-poor soils. Steel model piles, embedded in artificially frozen cohesionless soil, are subjected to both sustained pull-out forces and constant rates of displacement to observe the creep behaviour and acquire load-deformation curves, respectively. Temperature, as the main variable of interest, is increased from a lower limit of -10°C up to the point of melting. During different stages of the temperature rise, both skin deformations and temperatures are recorded at various depths along the pile shaft. Significant reduction of pullout capacity and accelerated creep behaviour is found to be the primary consequences of rising temperature. By investigating the different pull-out capacities and deformations measured during step-wise temperature change, characteristics of the transition from frozen to unfrozen soil-structure interaction are studied.Keywords: Adfreeze, frozen soil-structure interface, ice-poor soils, pull-out capacity, warming permafrost
Procedia PDF Downloads 1056018 A New Lateral Load Pattern for Pushover Analysis of RC Frame Structures
Authors: Mohammad Reza Ameri, Ali Massumi, Mohammad Haghbin
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Non-linear static analysis, commonly referred to as pushover analysis, is a powerful tool for assessing the seismic response of structures. A suitable lateral load pattern for pushover analysis can bring the results of this simple, quick and low-cost analysis close to the realistic results of nonlinear dynamic analyses. In this research, four samples of 10- and 15 story (two- and four-bay) reinforced concrete frames were studied. The lateral load distribution patterns recommended in FEMA 273/356 guidelines were applied to the sample models in order to perform pushover analyses. The results were then compared to the results obtained from several nonlinear incremental dynamic analyses for a range of earthquakes. Finally, a lateral load distribution pattern was proposed for pushover analysis of medium-rise reinforced concrete buildings based on the results of nonlinear static and dynamic analyses.Keywords: lateral load pattern, nonlinear static analysis, incremental dynamic analysis, medium-rise reinforced concrete frames, performance based design
Procedia PDF Downloads 469