bluuebunny/crossref_metadata_2025 huggingface dataset:
Torque Simulation on NI REBCO Pancake Coils during Quench
Authors: Noguchi So , Hahn Seungyong
Published: October 2019

This paper presents the unbalanced torque generated in No-Insulation (NI) REBa2Cu3O
x
(REBCO, RE = Rare Earth) pancake coils after a normal-state transition. The NI REBCO pancake coil has a high thermal stability, and it is desired to apply to ultra-high field magnets. When an NI REBCO pancake coil locally transitions into a resistive state, the operating current bypasses a normal-state-transitioned turn to adjacent turns in the coil-radial direction, and the amount of heat generation can be reduced. That is an inherent feature of NI REBCO pancake coils. However, when a radial current flows in a magnetic field, a Lorentz force is generated toward the coil-circumferential direction, i.e. torque. In case that the coil radius and the external magnetic field are very large, the extremely large torque is generated, and it could damage the magnet itself and/or the joints to terminals with a mechanical factor. Therefore, it is necessary to investigate the behavior of the torque generated in the NI REBCO pancake coil after the quench.

In this paper, we present the numerical simulation results of the behaviors of the torque generated in the NI REBCO double pancake coil after quench. Their current, thermal, and mechanical behaviors are simulated by a partial element equivalent circuit (PEEC) method and 2-D thermal finite element method (FEM). The behaviors are different depending on the coil size. In addition, the behavior is presented when the operating current is suddenly shut down after quench.
Recent Progress of the High-Temperature Superconducting Cable Project in Japan
Authors: Mimura Tomoo , Masuda Takato , Yaguchi Hiroharu , Fukushima Hiroyuki
Published: October 2019

We have spent considerable time studying high-temperature superconducting (HTS) cable for a long time. In Japan, a national project of the HTS cable system in a real grid operation, funded by the New Energy and Industrial Technology Development Organization (NEDO), started a decade earlier, which meant we could carry out real system operation for a year several years ago. We subsequently studied two issues on a new national project. One involved improving the performance of the cooling system, while the other involved safety verification against events possibly occurring in a system such as a ground fault or a short circuit. I will report on the outline.
Optimum design of cryogenic pump for circulation cooling of high temperature superconducting cables
Authors: Tadakuma Kenta , Kajikawa Kazuhiro , Kamioka Yasuharu , Ishiyama Atsushi , Imagawa Shinsaku , Nakamura Taketsune , Hirai Hirokazu , Ozaki Shinsuke
Published: October 2019

Pressure drops and temperature rises caused by the cooling with liquid nitrogen are evaluated for two typical examples of HTS cables. One is the three-in-one-type AC cable located inside a corrugated pipe, and the other is the single-core-type DC cable located inside a straight pipe. The theoretical expressions of pressure drop and temperature rise indicate the contributions from three components such as the friction between the liquid nitrogen and the wetted surfaces, the ratio of the heat input to the mass flow rate of liquid nitrogen and the vertical change of position along the cooling pipe. The numerically estimated results are validated by comparing them with the test results carried out by the other groups. Furthermore, the maximum feeding distance of HTS cable can be determined by adjusting the flow rate of pump if the maximum permissible pressure drop and temperature rise are fixed in advance.
Emulation and experimental analysis of an axial superconductor magnetic bearing
Authors: Rodriguez E , Dos-Santos G , Huang Z , Wang W , Deng Z
Published: October 2019

Today the high-speed and high-performance systems are each more important for many areas like industry and transport system. The magnetic levitation system can be used to improve the performance. For superconducting levitation, it is important to know the behavior of levitation force. However, its behavior is not completely known and studies about it are necessary. This work presented a description of the test bench and a brief introduction to the new software developed to the magnetic levitation measurement system (SCML-02). The system tested is compound by a superconducting bulk and permanent magnet. This system makes data acquisitions using the load cells and the data processing is built by the new software developed in the LabVIEW. The results are verified and compared by simulations which were done in the software of finite elements and measurement data of the magnetic levitation done at Federal University of Rio de Janeiro - UFRJ. The measurements of the new system show compatible results with the simulations and the measurement data done at UFRJ. Therefore, with this new software, the users can easily to do magnetic levitation measurements through an interface easy to understand.
Evaluation of loss characteristics of superconducting magnetic bearings for LiteBIRD satellite by three-dimensional finite element method analysis
Authors: Hirota Y , Ohsaki H , Terao Y , Enokida H , Sakurai Y , Matsumura T , Sugai H , Katayama N
Published: October 2019

The polarization modulator of LiteBIRD satellite is required to be used by continuously rotating the half-wave retarder under a low temperature environment of about 10 K. Then, it becomes an important issue to reduce heat generation due to rotation loss. Therefore, a rotation mechanism in a cryogenic environment by a superconducting magnetic bearing (SMB) using the pinning effect of the bulk superconductor has been studied. In SMB, because of the pinning effect of superconductor, it is possible to rotate the half-wave retarder with stably floating, and it is possible to avoid frictional heat due to contact. The half-wave retarder is incorporated inside the rotating part of the superconducting magnetic bearing composed of the permanent magnet ring and the iron yoke. At this time, since the permanent magnet ring divides the parallel magnetized permanent magnets into pieces, a gap is formed at the joint of the permanent magnets. For this reason, the magnetic field distribution generated by the permanent magnet ring is not uniform. Although SMB can reduce friction as compared to mechanical bearings, the magnetic properties of the bulk superconductor change due to the magnetic field fluctuation caused by such ununiformity of the magnetic field, resulting in energy loss. In this study, heat generation in bulk superconductor in SMB is evaluated by three-dimensional finite element method. First, using JMAG Designer 17.0, the magnetic field distribution created by the rotor side is obtained by static magnetic field analysis. Next, using the COMSOL Multiphysics 5.3a, by applying the magnetic field distribution created by the rotor side obtained above and rotate the magnetic field, the loss generated in the bulk superconductor is investigated. The resulting loss value satisfied the required value.
Data Analysis And Prediction On Cloud Computing For Enhancing Productivity In Agriculture
Authors: Ashokkumar K. , Divya Chowdary D. , Divya Sree Ch.
Published: October 2019

Introducing a concept to increase productivity and predict the crops from the diseases. To find the leaf characteristics using image processing to detect the diseases and pests that are present in leaves. In agriculture the main important aspect is to take proper steps to increase the production, which means to know the state of leaves condition in the field. In this undertaking the programmed system recognizes the qualities of the leaves. The programmed leaf attributes recognition is basic one in observing extensive fields of yields, and to naturally distinguish indications of leaf attributes when they show up on takes off. The basic leadership framework uses the picture portrayal and managed classifier of Neural Network. Picture preparing procedures for this sort of choice examination includes preprocessing, highlight extraction and characterization organize. In this procedure, the picture is taken and that can be resized if required the locale of intrigue choice can be performed. Here, shading and surface highlights are extricated from a contribution for organize preparing and grouping. Shading highlights like mean, standard deviation of HSV shading space and surface highlights like vitality, differentiation, homogeneity and connection. The framework will be utilized to order the test pictures naturally to choose leaf attributes. For this approach, programmed classifier Neural Network (NN) is utilized for grouping in light of learning with some preparation tests of that same classification. This system utilizes digression sigmoid capacity as portion work. At long last, the mimicked result demonstrates that utilized system classifier gives least blunder amid preparing and better exactness in order. This helps to read the classifier (Characteristics difference of the input image).By using the Threshold values we can detect the pests/diseases and also helps to give the required data about the diseases, details of pesticides and other like required quantity of the pesticides and displays the present market prices for the selected crop.
Sign Board Monitoring and Vehicle Accident Detection System Using IoT
Authors: Ashokkumar K. , Venkata Deepak Ch. , Vamsi Rattaiah Chowdary D.
Published: October 2019

Abstarct: The Rapid growth of technology and infrastructure has made our lives easier. The advent of technology has also increased the traffic hazards and the road accidents take place frequently which causes huge loss of life and property because of the poor emergency facilities. Our project will provide an optimum solution to this draw back. According to this project when a vehicle meets with an accident immediately Vibration sensor will detect the signal or if a car rolls over, and vibration sensor will detects the signal and sends it to RASPBERRY PI controller. Alcohol detection, eye blink is performed by the RASPBERRY PI Microcontroller sends, it alert mail through the IOT to the parents or a rescue team. So the person can immediately then after conforming the location necessary action will be taken. If the person meets with a small accident or if there is no serious threat to anyone’s life, then the alert message can be terminated by the driver by a switch provided in order to avoid wasting the valuable time of the medical rescue team. This paper is useful in detecting the accident precisely by means of both vibration sensor and Alcohol detection, eye blink sensor.. As there is a scope for improvement and as a future implementation we can add a wireless webcam for capturing the images which will help in providing driver’s assistance.
Analysis of Road Accident
Authors: Sundar Kumar P. , Viswanadham V. , Bharathi B.
Published: October 2019

The paper focused the main idea of this project the reduce road accidents by dissecting the accident prone areas and taking security methods to diminish them. Generally road Accidents frequently occur, due to two main reasons, one is drivers mistake due to over speed or due to avoiding signals and may be due to ignoring traffic rules and the second case is external factors like road conditions, atmospheric conditions bringing this into mind we made application contains various limits and to inspect the standard reason of mischances. The created application stores a huge data of earlier years in the HADOOP to dissect why the mishaps occur in one region consistently. For exploring this colossal data we are using Big data for the faster examination. As Big data can store, control, separation and besides can mine tremendous fender bender dataset. The include is utilized Map reducing for organizing information and for the examination of unstructured information Spark is being utilized. By analyzing this we can take some safety measures to avoid the accidents which are being taken place in one area for to the similar reason.
Secure and Trustable Routing in Wireless Sensor Networks Using Active Detection Routing Protocol
Authors: Karthikeyan S. , Venkata Suhas Reddy Katikareddy , Venkata Bypu Reddy Katasani , Ravi T.
Published: October 2019

A Wireless Sensor Network (WSN) contains gadgets that are self-sufficiently conveyed in space used to direct the physical and natural conditions with the assistance of sensors. They are primarily utilized as a part of security basic applications, for example, checking nature, following the environment and controlling regions. As a result of the asset impediment and computational limitations the WSNs are straightforward to different security assaults. Dark opening assault is a genuine assault which seriously influences the bundle exchange from source to goal. Here the Active Trust conspire is utilized to stay away from the Black opening assault. The Active Trust conspire keeps away from the dark openings through Active discovery directing and information steering which enhances the course security. Both complete hypothetical investigation and exploratory outcomes demonstrate that the execution of the Active Trust conspire is superior to anything that of past examinations. Dynamic Trust can fundamentally enhance the information course achievement likelihood and capacity against dark gap assaults and can enhance arrange lifetime.
Optimization of Thin film for the design of H-Alpha Filter
Authors: Jegan Antony Marcilin L. , Nandhitha N.M. , Kural Mathi R.
Published: October 2019

Electrical power plays an important part and it is a critical contributing element for a most of the developments. Numerous power plants are accessible for the production of electrical energy and the most significant power sources are coal, solar power, wind, atomic, gas, Biomass, and so on. Power is also produced from plasma which is an ionized gas. It is said that while producing power from plasma because of some unprecedented reason the plasma begins to deteriorate which leads to the emission of enormous amount of gases including H-alpha which is of wave length 656.3 nm and it is necessary to design a filter to detect the H-alpha discharges. In this paper, a filter design for the H-alpha emission is discussed.
A Robotic Platform to Identify Gas Pipe Leakage Using IOT
Authors: Joshila Grace L.K. , Sai Teja K. , Sai Kishan Reddy J.V.
Published: October 2019

Gas pipes play a very vital role in cities as well as industries thus directly related to the growing economy of our country. Gas leakages in our present day world lead to many fire accidents and pose a greater threat. To place sensors at each section of the pipe is difficult as well as time taking and costly. So, we are proposing an innovative robot that clings to the outer surface of a gas pipe and moves along the pipe to detect gas leakages. The robot keeps on moving along the pipe surface and will monitor any gas leakage, when it detects it will send the transmit location using an interface GPS sensor to the IOT login system, we use a software called UBIDOTS to display the gas leakage position and it also sends alert messages over IOT. At last, we design a robot which is automated and has an insect like structure that moves along the gas pipe and it detects the gas leakages at a very low cost.
A Millimeter Wave based Circular Slot Loaded Microstrip Patch Antenna for 5G Communication
Authors: Karthikeyan V. , Vignesh S. , Ayyavar Reddy K. , Bhargavi Reddy G. , Aparna Sekhar R. S.
Published: October 2019

This paper presents a microstrip patch antenna for 5G communication at the frequency range of 32GHz. The patch is loaded with multiple circular slots to improve the performance of the antenna. It consists of RT duroid substrate with low dielectric loss tangent 0.0009, dielectric constant 2.2 and thickness 0.5mm, PEC ground and PEC patch. Four various patch antenna with slot array based antenna has simulated on Ansoft HFSS (High Frequency Structural Simulator) Platform. The overall dimensions of designed antennas are 6mm x 6mm x 0.5mm. The performance of antenna is analysed by using simulated results of reflection coefficient, VSWR, gain, bandwidth and directivity and antenna parameters are compared with four antennas. The proposed antennas of reflection co-efficient characteristics is below -10dB at the resonance frequency.
Coplanar Waveguide fed MIMO RDR Antenna for ISM Band Frequencies
Authors: Dileepan D. , Sanmugasundaram R. , Natarajan S.
Published: October 2019

A Multiple-Input-Multiple-Output (MIMO) Rectangular Dielectric Resonator Antenna (RDRA) is presented in this paper for industrial scientific and medical applications with 2.45 GHz. The geomentry of proposed antenna is fabricated on low cost FR-4 substrate with dielectric constant of 4.4 with coplanar waveguide (CPW) inductive slot and its physical dimension is 69.3 X 73 X 1.6 mm3 (Length x Width x Height). In this work, RDRA uses two orthogonal modes with two different mechanisms and they are coplanar waveguide (CPW) and coaxial probe. The proposed MIMO RDR Antenna is expected to give various features such as isolation beyond 20 dBi range over the frequency of operation, positive gain, VSWR, Z-parameters display, 2-D current distribution using azimuthal and elevation patterns.
Detection and Content Retrieval of Object in an Image using YOLO
Authors: Vinoth Kumar B , Abirami S , Bharathi Lakshmi R J , Lohitha R , Udhaya R B
Published: October 2019

It is easy for human beings to identify the object that is in an image. Even if the task is complex, human beings require only a minimal effort. Since computer vision is actually replicating human visual system, the same thing can be achieved in computers when they are trained with large amount of data, faster GPUs and many advanced algorithms. In general terms, Object detection can be defined as a technology that detects instances of object in images and videos by mimicking the human visual system functionalities. The motivation of the project is making the search process easier for the user i.e., if the object is very new for the user and he has no idea about it, he can upload a picture of that object and the algorithm will detect the object and gives a description about it. The objective of the project is to detect the object in an image, once the object is detected, the label i.e., the name of the detected object is searched in Wikipedia and few lines of description about that object is retrieved and printed. Also, the label is searched in google and the URL of the top pages with content related to the label are also displayed. The detection of object in an image is done using YOLO (You Only Look Once) algorithm with pre-trained weights. Previous methods for object detection, like R-CNN and its variations, used a pipeline to perform this task in multiple steps. This can take some time for execution, complex optimization may be involved because individual training of components is required. YOLO, does it all fastly with a single neural network. Hence, YOLO is preferred.
Perspectives of climate change adaptation of building areas against heat waves
Authors: Ortlepp R , Schiela D
Published: October 2019

Summer heat stresses the inhabitants of densely populated residential areas. It is one of the most serious environmental impacts. Heat can affect human health and lead to additional deaths even under current climatic conditions. Climate projections show a clear change signal for summer heat in the future. This means an increase in hot days and tropical nights, especially in urban quarters without networked green and fresh air corridors. This results in a high need for action with regard to summer heat protection and climate change adaptation measures. This paper makes a contribution to the 11th SDG “Sustainable Cities and Communities” with the target to improve the adaptation to climate change and resilience to disasters in terms of summer heat. It deals with the question of how adaptation measures can reduce the burden of summer heat on residents in their homes with the aim to decrease the disaster risk. The paper reviews current knowledge about common adaptation measures, summarizes first results of thermal simulation calculations for the evaluation of effectiveness of adaptation measures, including the effects of residents’ behaviour, and makes recommendations for preventive action. The results show that the development of sets of adaptation measures for summer heat waves must not be regarded separate neither from adaptation for cold winter seasons nor from climate protection regarding energy efficiency. Further, it shows the importance of including the aspect of acceptance by the residents in the planning process to make climate change adaptation of their buildings successful.
Effect of nickel slag as a sand replacement in strength and workability of concrete
Authors: Edwin R S , Ngii E , Talanipa R , Masud F , Sriyani R
Published: October 2019

Concrete containing cement, sand, gravel, nickel slag, water and superplasticizer were processed using normal intensive mixing. The strength of concrete is determined by the interfacial zone between binder paste and aggregates. Due to the weathering of natural aggregates with time, a morphology with rounded edges is obtained, reducing the interlocking with the paste. Hence, it is interesting to investigate the use of nickel slag as a sand replacement in concrete since this material has sharp angular edges, which can improve the cohesion of the concrete. This research investigates the use of nickel slag as the replacement of sand in concrete. Various concrete samples were produced with the increasing nickel slag content from 0% to 50% every 10%. A water-cement-ratio of 0.35 was chosen in this study. Concrete mixes were assessed for their compressive strength and workability. The obtained results showed that the strength of the concrete increases together with the increasing nickel slag content in the concrete mixture. Also, the results demonstrated that the slump increases with rising nickel content. In addition, there was no bleeding in fresh concrete mixture in this research.
Knowledge, skills and attitudes of civil engineers in Indonesia
Authors: Setiawan H , Raharjo F
Published: October 2019

Civil engineer plays an important role in construction industry because they have been entrusted to create sustainable world and to enhance the quality of life. In order to play their role successfully, civil engineer needs to possess many and varied knowledge and skills, as well as supported by embracing attitudes. This study is aimed to explore the importance and achievement of attributes of civil engineers based on profile of the 2025 civil engineer that has been launched by American Society of Civil Engineering (ASCE). The attributes consist of 21 points those are organized into the categories of knowledge, skills, and attitudes. The research was conducted by asking respondents to fill out a questionnaire to assess the importance and performance of each attribute. The data has been collected from 100 practitioners who work in various construction companies in Indonesia. Descriptive Statistic, Importance Performance Analysis (IPA) and correlation analysis have been implemented to analyze the data. The study found communication is considered as the most important attribute and in a highest performance. Thoroughly the Spearman Rank Correlation analysis shows the level of importance and performance have a strong and positive correlation. However, the importance and performance level of knowledge about sustainability only in the rank of 16 and 18. This result shows that in Indonesia knowledge about sustainability has not been considered important.
Construction pollution in Brunei
Authors: Rahman M M , Yusof I B H M , Asli R A
Published: October 2019

Despite its considerable contribution to the economy of a country, construction industry is held responsible for degrading sustainability in general, and environment in particular, in many ways. For example, it consumes about 40% of global resources and, generates almost half of all the pollution. However, their nature and degree may vary according to the type and scale of the projects, and often can be area or country specific. Especially, no research seems to have been conducted previously in Brunei Darussalam for identifying pollution from construction. Therefore, this study was undertaken to identify sources of construction related pollution and their mitigating strategies. However, this paper focuses only on sources of pollution and summarizes the outcomes from a questionnaire survey of 107 responses, comprising clients, contractors and consultants. Five groups of pollution were identified, with various sources within each group: air pollution that includes dust and GHG (greenhouse gas), water pollution, noise pollution, and solid waste. All the sources were observed to have different degrees of criticality, i.e. either critical or more critical, implying a general critically of the identified sources of pollution. However, the focus seems to be on developing an industry wide awareness towards pollution, with contractors to play key role to pollution and relevant activities, probably due to their engagement in executing construction at sites. The next step of the study is to further investigate for a holistic solution, while the outcomes are expected to help policymakers to develop and/or take appropriate measures to control pollution.
Managerial flexibility role on financial investment analysis: a case study of public housing
Authors: Hermawan F , Harsono A C , Suliantoro H
Published: October 2019

The limitations of Discounted Cash Flow (DCF) method for capturing the opportunity value phenomenon in the uncertainty of housing investment analysis cause difficulties in the decision-making process for the investors. Flexibility factor becomes the obstacle for investors in project uncertainty. Real Options Analysis (ROA) is an important factor included in the DCF method because it offers managerial flexibility in the uncertainty of housing investment decision making. Flexibility in ROA is a right and investors do not have an obligation to respond to uncertainty in project investment. In this research, the type of flexibility on ROA used is an option to carry out promotional activities. The research results indicate that promotional activities affect the increase in Net Present Value (NPV) so that the benefits are maximized. Comparison of the results of investment analysis between ROA and DCF methods indicates an added value due to the existence of such flexibility. The investment simulation of ROA method was conducted using Monte Carlo method approach. The role of flexibility from the simulation is obtained by increasing the added value by 5.2%, and optimal promotion occurs in the first two years of investment.
Microbially induce calcite precipitation as bio grouting by bacillus subtilis on its shear strength parameter effects on organic soil (peat) from Siak Regency Riau Province Indonesia
Authors: Syarif F , Hardianto M F , Davino G M
Published: October 2019

Contemporarily, the use of bacterial Calcite precipitation (bio grouting) is popular as a ground improvement technique for sandy soil. However, this was not frequently applied to organic or peat variety. Meanwhile, on the island of Sumatra, the province with the largest peat terrain is Riau, expanding an area of ± 4.04 million Ha, which is 56.1% of the total mulch land in the region, where Siak is one of the districts, possessing a fairly large portion. Furthermore, numerous problems ensue due to this structure, especially during the construction of infrastructure. Therefore, this study focused on bacterial Calcite precipitation from Baciluus Subtilis, and its effect on the Shear Strength parameters of organic soil, where a special injection system was prepared for inducing the bacterial solution to the samples, which were tested by UCS tool, in order to ascertain shear strength parameter, after 3 days. Moreover, through this research, it is hoped that the technique adopted improves engineering performance, especially in the areas of increasing shear strength parameters of organic or peat soil. Hence, this procedure is suitable and also assists in reducing challenges in construction of infrastructure within Siak district.
Determining the track condition using soil properties - part 1
Authors: Schuk V , Rapp S , Martin U , Wang B
Published: October 2019

The track condition in conventional ballast construction is decisively determined by the condition of the sub-ballast and the subgrade. An indicator for the assessment of the track condition is the track modulus, which can be calculated by measuring the rail deflection under load or according to the soil properties. The track modulus describes the ratio between vertical loading and elastic deflection of the sleeper support. This is the first of two papers concerning a theoretical approach to estimate the track modulus of the soil by soil properties. The approach’s advantage is to be completely independent from the superstructure condition. Therefore the components of the superstructure along the track axe must not know for calculating the track modulus. Borings with direct ground exploration results and ground penetrating radar measurements are used to determine the soil condition at the track level. After the allocation of the soil properties to each layer, the cone model is used to calculate this average value of the soil properties. Subsequently, the track modulus of the soil is determined by using the average value of the soil properties. Based on the value of the track modulus of the soil, the track condition can then be determined.
Determining the track condition using soil properties - part 2
Authors: Schuk V , Rapp S , Martin U , Wang B
Published: October 2019

The track condition in conventional ballast construction is decisively determined by the condition of the sub-ballast and the subgrade. An indicator for the assessment of the track condition is the track modulus, which can be calculated by measuring the rail deflection under load or according to the soil properties. The track modulus describes the ratio between vertical loading and elastic deflection of the sleeper support. This is the second of two papers concerning a theoretical approach, which allows the estimation of the track modulus of the soil for the layer arrangement of stiff on soft soil layers by using a homogeneity parameter. The homogeneity parameter has to be considered, so that the influence of the layer arrangement, the layer depth and the soil properties can be examined. Borings with direct ground exploration results and ground penetrating radar measurements are used to determine the soil condition at the track level. After the allocation of the soil properties to each layer, the cone model is used to calculate the average value of the soil properties. Based on the value of the track modulus of the soil, the track condition can then be determined.
An evaluation of the flood diversion project due to extreme rainfall event in Taipei City
Authors: Wu S , Jang J , Wu T , Lin J , Li B
Published: October 2019

Governments in Taiwan attach great importance to flood control and disaster mitigation project. Good simulation and estimation in advance are the key point to prevent damages and losses caused by flood disasters. The main objective of this study is to investigate the effectiveness of the Drainage and Flood Control System in Wenshan District completed by the Taipei City Government. SWMM (Storm Water Management Model, US Environmental Protection Agency), a dynamic rainfall-runoff simulation computer program designed for runoff water quantity and quality of single or continuous events in urban areas, is utilized to perform the simulation and analysis in this study. Based on known basic data of facilities such as pipelines, channels, and water storage system, and by setting data related to typhoons and heavy rains from the past records, the runoff at a certain period in each area and the flow and depth in each pipeline are estimated and simulated. By comparing the simulation results with the results before the construction, we can evaluate the effectiveness on the Drainage and Flood diversion system and predict the possible defects. Accordingly, the engineering plan can be modified promptly before the construction to enhance the effect of flood control and disaster mitigation.
Experimental and numerical investigations on the concrete edge failure of anchor groups of arbitrary configurations
Authors: Bokor B , Sharma A , Hofmann J
Published: October 2019

Concrete edge failure often governs the failure of anchorages, which are installed close to the concrete edge and are loaded in shear perpendicular towards the edge. The design provisions for concrete edge failure given in the current codes are rather limited in applicability. Only anchorages arranged in a rectangular pattern are allowed. For anchorages without hole clearance, the maximum permissible anchor pattern is with three anchors in a row, and for anchorages with hole clearance, a maximum of only two anchors in a row is allowed. Furthermore, for anchor groups with multiple anchor rows loaded in shear perpendicular to the edge, the failure load may be calculated by assuming the failure crack initiating from the front anchor row (EN1992-4) or by assuming the failure crack initiating from the back anchor row (fib Bulletin 58, ACI 318). No design guidelines exist for non-rectangular anchor configurations. In such cases, the design is based on engineering judgement. In this study, experimental and numerical investigations were performed on anchor groups of triangular and hexagonal configurations to study the concrete edge failure. It was observed that the failure crack always initiates from the back anchor row, even in case of anchor groups, where the first cracking is associated with the first anchor row. The first cracking may have an influence on the displacement behaviour of the group, which might limit the design in SLS. However, this is dependent on the displacement behaviour of individual anchors within the group, edge distance, spacing and hole clearance.
Applications of density functional theory to heavy metal binding to magnetic-cored dendrimer
Authors: Kim H-R , Boukhvalov D W , Park J-W
Published: October 2019

Magnetic-cored dendrimer (MD) is a nano-material composed with the magnetite nanoparticle in the core and dendritic branches developed on the surface of the core. Due to the unique structure and magnetic property of the MD, it has been studied for various environmental applications including the adsorption. With a large number of the terminal group, the poly (amidoamine) dendrimer provides many possible binding positions to various kind of contaminants. It has been reported that the heavy metal adsorption shows different affinity depending on heavy metal species in the aqueous phase. In this study, the MD was synthesized and their binding efficiency experimented with four different dissolved heavy metals of Pb (II), Cu (II), Zn (II), and Cr (VI). The maximum adsorption capacity of heavy metal was in the following order: Pb2+ > HCrO4- > Zn2+ > Cu2+. The interaction between the MD and the targeted heavy metal was calculated using the density functional theory (DFT). A pseudo-potential code SIESTA model was used. The calculated enthalpy of each metal indicated an agreement with the experimental result. A specific binding position and energies of different heavy metal species were confirmed through DFT calculations. The calculated enthalpy demonstrates structural and dynamical characteristics between MD and heavy metals. The binding preference of MD to a different kind of heavy metal provides useful information for the environmental applications.
Precast segmental bamboo reinforced concrete beams with bolted connections subjected to flexural loads: an experimental investigation
Authors: Haryanto Y , Hu H-T , Han A L , Wariyatno N G , Sudibyo G H , Hidayat B A , Naqiyah K
Published: October 2019

Indonesia is one of the wealthiest botanically countries in the world. There are more than 130 species of Bamboo can be found in this country. Bamboo is a natural raw material which is one of the fastest growing plants that has many advantages as a construction material. We conducted an experimental investigation to study the performance of the precast segmental bamboo reinforced concrete beams with bolted connections subjected to flexural loads. Tests were carried out on three specimens with dimensions of 120 mm x 150 mm x 1000 mm, consisting of one control beams (BK), one precast segmental bamboo reinforced concrete beam with four bolted connections (BS4), and one precast segmental bamboo reinforced concrete beam with six bolted connections (BS6). We found that the load carrying capacity of precast segmental bamboo reinforced concrete beams with four bolted connections (BS4) and six bolted connections (BS6) had a decrease of 57.99% and 55.62% respectively compared to control beam (BK). Similarly, the deflection ductility index of the precast segmental bamboo reinforced concrete beams with four bolted connections (BS4) and six bolted connections (BS6) had a decrease of 49.78% and 46.59% respectively compared to control beam (BK). Also, we observed that the crack pattern developed in the control beam indicates a flexural failure mechanism while the crack pattern developed in the precast segmental bamboo reinforced concrete beams indicates a shear failure mechanism. As a conclusion, this study will significantly contribute to the growing development of research on the bolted connection system in bamboo reinforced concrete members, especially in Indonesia.
Optimum and performance of absorber with zero damping
Authors: Arfiadi Y , Frans R
Published: October 2019

This paper considers optimum parameters tuned mass damper (TMD) as a vibration absorber with zero damping. Generally, tuned absorbers with damping have been considered to be applied to the structures. While adjusting damping constant produces additional complexity in real applications, this paper investigates the use of absorber with zero damping. The properties of the absorber to be designed then is reduced to only its spring constant, while the damping is set to zero throughout the design process. To optimize its spring constant, genetic algorithm (GA) with real coding is utilized. With the optimized spring properties obtained from the optimization, the performance of structures is then investigated under several earthquake excitations. The performance of the optimum absorber with zero damping is also compared with the one when arbitrary damping presents in the absorber. The simulation results show that the performance of the absorber with zero damping is smaller compared to the one of absorber with damping. However, the response of absorber with damping tends to decrease when time increases.
Effect of loss in concrete cover during fire on the predicted temperature distribution
Authors: Lakhani H , Hofmann J
Published: October 2019

The paper presents a numerical study conducted using in-house code for 2D transient heat-transfer analysis. The code solves the governing differential equations for transient heat-transfer using finite difference scheme and iterative solver. The code takes the information related to loss of concrete cover as an input and update the thermal boundary conditions (moving BCs). The validation of the code against experimental results available in literature has been presented. The paper also presents a parametric study to investigate the effect of corner spalling on predicted reinforcement temperatures for a beam. The parameters investigated includes: depth of lost concrete cover, time at which the cover is lost and fire exposure (ISO-834 and design fire). As expected, higher reinforcement temperatures were observed for higher loss of corner concrete corner cover but the effect of smaller cover loss (28% diagonal cover) was negligible. It was also observed that for longer fire exposures, depth of lost cover is more important than the time at which it is lost. In case of design fire exposure, it was observed that; large cover lost during heating-phase results in a higher temperature, which still occur during the cooling-phase but earlier as compared to the reference case.
Creep behaviour of tension loaded adhesive anchors in non-cracked low strength concrete
Authors: Mahadik V , Hofmann J
Published: October 2019

Post-installed anchorages or reinforcements using bonding adhesives are invariably used in the present day construction industry. Although, various attempts to develop a generalized theory for design and analyses of adhesive anchorages have been made, the actual anchorage behaviour is still considered to be dependent on the adhesive product in use. The creep behaviour of adhesive anchors were investigated again intensively after several failure were observed. Several research experiments in this regard are performed by different researchers to establish a new procedure of failure accounting the creep effects of adhesive anchors. This work discusses the results of an experimental program undertaken at the University of Stuttgart, for establishing the time-to-failure behaviour under sustained loads for two different adhesive anchor products. The complete test program included reference pull out tests to evaluate the ultimate capacities. Sustained load tests were performed for the load levels corresponding to 85%, 75% 65% and 55% of the ultimate capacity observed in the reference tests. The test program also included sustained loading tests at different temperature conditions like ambient temperature (23°C) and moderately high temperature (43°C). A comparison of the creep behaviour for standard and sub-standard installation condition was also included in the test program to see the effect of a reduced installation cleaning process. In this paper, the results for standard installation with ambient temperature of 23°C are used to demonstrate the sustained load effects in the framework of time-to-failure behaviour. The possibility of arriving at a safe load level which can be sustained throughout the design lifetime of 50 years is discussed using the time-to-failure curves.
Local strengthening of anchorages with post-installed (supplementary) reinforcement
Authors: Vita N , Sharma A , Hofmann J
Published: October 2019

The existing anchorages in reinforced concrete structures may need strengthening due to an increase in the applied load during its lifetime. In certain cases, due to limited dimensions of the structural member (e.g. concrete slab or beam), the size of the anchorages that can be used is also limited and the standard design of anchorages may not be enough to provide required load-carrying capacity. In these above-mentioned cases, a method to strengthen the anchorage may be needed. In the present work, it is attempted to develop a method for strengthening of anchorages under tension loads by using post-installed reinforcing bars. Tests were performed on anchorages using bonded anchors (single anchors) without and with different configurations of post-installed reinforcement for strengthening. The main objectives were to investigate the influence of the reinforcement arrangement on the ultimate load capacity and on the load-displacement behavior of the anchorages. The bonded anchors were selected considering the ease of installation and freedom to choose the test parameters. The tests were performed on anchorages away from the edge. The test parameters were determined in a way that in the case of reference tests, concrete breakout was the dominant failure mode. The reinforcement was placed relatively close (with a distance of approx. 0.4·hef) to the anchor. The results clearly show that the post-installed reinforcement can result in a considerable increase in the load and deformation capacity of the anchorage. Depending on the amount and arrangement of the reinforcement, a change in the failure mode from concrete cone breakout to strut-failure could be observed. It was also shown that for the same amount of reinforcement provided, the arrangement of the reinforcement had a considerable influence on the effectiveness of the strengthening. To understand the mechanics better, in certain tests, strain gauges were applied on the reinforcing bars, which showed the interaction between the contribution of concrete and that of reinforcement in resisting the applied loads.
Ecological construction method by the deployable bridge
Authors: Chanthamanivong K , Ario I , Yokotani Y
Published: October 2019

Global warming is a result of greenhouse gas emission from various sources, such as industrial manufacturing, transportation, and construction activities. Among these, construction activities further involve the destruction of the natural environment, which should be protected for ecological balance. During construction, the natural environment should be protected by preserving the natural scenery while ensuring safe and rapid construction. To achieve this, the construction structure needs to be designed with the features of light weight, high efficiency, and safety using deployable structures. Deployable structures are superior over general structures because they can be extended in any area within a few hours and have less impact on the natural environment of the construction site, thus providing an alternative choice for environmental protection and conservation. In a deployable structure model, deployment and truss structures are combined using the scissor mechanism concept. However, the structure is required to remain in a stationary condition. Therefore, this study investigates the equilibrium theory of the scissor structure and presents the methodology of a new bridge construction method.
Seismic vulnerability assessment of bridges using analytical hierarchy process
Authors: Djemai M C , Bensaibi M , Zellat K
Published: October 2019

Bridges play an important role in transportation network. After an earthquake, bridges must remain functional. To reach this goal, vulnerability study must be conducted. The aim of this study is to develop a vulnerability index method for bridges. The most important parameters influencing the seismic behaviour of bridges are identified, and a seismic vulnerability assessment model is developed using the analytical hierarchy process (AHP) to quantify the contribution of each parameter. Using the developed model, several bridges are treated and the obtained results show a good adequacy with in situ observations.