Study on Testing the Relative Density of Coarse Aggregate by Vacuum Method instead of Basket Method

. In this paper, Vacuum Method was offered to test the relative density of coarse aggregate instead of basket method for the quick and exact mixture design of asphalt mixture. Firstly, the testing principle Vacuum Method was obtained by analyzing the experiment characteristic features of Vacuum Method and basket method. Secondly, the stability and accuracy of Vacuum Method were analyzed by testing the relative density of different kinds of coarse aggregate. Finally, the experiment conditions (the vacuum degree and pressure-holding time) were obtained through Comparison Experiment to the conventional basket method. The results show that the relative density of coarse aggregate can be tested quickly and exactly by Vacuum Method. This not only shortens the experiment time, but also raises working efficiency.

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Path Planning of the Intersecting Line of Cylindrical Pipes Welded by the Welding Robot

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.456.43 ◽

2013 ◽

Vol 456 ◽

pp. 43-49 ◽

Cited By ~ 1

Author(s):

Yong Quan Wang

Keyword(s):

Mathematical Model ◽

Path Planning ◽

Plane Curve ◽

Step Length ◽

Interpolation Error ◽

Welding Robot ◽

The Stability ◽

Stability And Accuracy ◽

Welding Procedure ◽

Working Efficiency

In recent years, the welding of the intersecting lines of cylindrical Pipes is gradually replaced by welding robot operation from the traditional manual welding. In this paper, the generalized mathematical model of the intersecting line of cylindrical pipes is presented, and the intersecting line is developed into plane curve. Using the method of equal step lengths, the welding trajectory path points are obtained. In order to guarantee the welding precision, the value of the step length is obtained by calculation according to the permitted interpolation error value. This paper also gives a flowchart, which shows the process of obtaining the welding path points of the intersecting line. This method is convenient for programming the welding procedure, improves the working efficiency and ensures the stability and accuracy of welding at the same time. Finally, a common example of cylindrical pipes intersection is given, and the welding path points are obtained using programmable drawing software.

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Karakteristik Marshall Campuran Asphalt Concrete Binder Course (AC-BC) Yang Mengandung Cangkang Kelapa Sawit Sebagai Agregat Kasar

Jurnal Ilmiah Rekayasa Sipil ◽

10.30630/jirs.16.2.216 ◽

2019 ◽

Vol 16 (2) ◽

pp. 113-123

Author(s):

Syaifullah Alli ◽

Mukhlis Mukhlis ◽

Lusyana Lusyana ◽

Fauna Adibroto ◽

Enita Suardi

Keyword(s):

Surface Layer ◽

Palm Oil ◽

Oil Palm ◽

Asphalt Concrete ◽

Coarse Aggregate ◽

Asphalt Mixture ◽

Minimum Thickness ◽

Palm Shell ◽

Oil Palm Shell ◽

The Stability

AC-BC coating is one type of hot mix asphalt with a minimum thickness of 4 cm. The most important characteristic of this mixture is the stability of the surface layer where the surface layer must be able to accept all types of work loads. As a foundation layer, the asphalt content it contains must be sufficient so that it can provide a waterproof coating. The aggregate used is rather rough compared to the surface wear layer. The aggregate requirement that dominates in the asphalt mixture makes us research what materials can be used as a mixture in the asphalt mixture. Palm oil waste provides an alternative opportunity as a material making up the asphalt mixture. The intended waste is oil palm shell which can be used as a substitute for coarse aggregate in asphalt mixture. The purpose of this study is to obtain the ACO BC mix KAO calculation without using an oil palm shell and using a palm oil shell with variations of 2.5%, 5%, 7.5%, 10%, 12.5%, and 15% as substitution of coarse aggregate and know the effect of adding palm shells to the mixture of test specimens on Marshall parameter values. Before the manufacture of test specimens, the materials are tested in advance in accordance with the 2010 Revised 3 General Specifications. 3. The addition of oil palm shells to the asphalt mixture showed an increase in KAO value. Based on the results of the study, the oil palm shell was suitable as an additive to the Asphalt Concrete-Binder Course (AC-BC) mixture because it met the requirements of the 2010 Revised 3 General Bina Marga General Specifications.Keywords: mixture of AC-BC, oil palm shells, KAO, Marshall parameters

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Standard of Crushing Value of Coarse Aggregates for Permeable Asphalt Mixture Based on Contact Stress between Aggregates

Journal of Engineering ◽

10.1155/2020/1261368 ◽

2020 ◽

Vol 2020 ◽

pp. 1-7

Author(s):

Tian Xiaoge ◽

Wang Xiaofei ◽

Yuan Huitong

Keyword(s):

Contact Stress ◽

Coarse Aggregate ◽

Asphalt Mixture ◽

Compression Tests ◽

Normal Contact Stress ◽

Normal Contact ◽

Deformation Curves ◽

Coarse Aggregates ◽

Technical Requirements ◽

The Stability

Crushing resistance of coarse aggregate is the key to the stability and durability of the skeleton structure of permeable asphalt (PA) mixture. To determine the technical requirements of crushing value of coarse aggregate used in PA mixture, step-loading compression tests were conducted on the mixtures of PA-13 and a control asphalt mixture AC-13, respectively. Virtual compression tests under the same loading conditions were simulated on the corresponding digital specimens with PFC2D®. By comparing the load-deformation curves obtained from the actual tests and virtual simulation, the values of the microscopic parameters of the two graded mixtures were obtained through trial calculation and adjustment. Then, the states of contact stress between aggregates in PA-13 and AC-13 mixtures under the standard crushing pressure (400 kN) were analyzed with PFC2D®. It was found that the average normal contact stress and the maximum normal contact stress between aggregates in PA-13 were 1.71 times and 1.28 times larger than those in AC-13, respectively. The crushing values of two different lithologic coarse aggregates were measured under different pressures, 400 kN or 600 kN, respectively. The crushing value criterion of coarse aggregates used in the PA mixture was suggested to be no greater than 16% after comparative analysis.

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Marshall Characteristics of Porous Asphalt Containing Low Density Polyethylene (LDPE) Plastic Waste

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/921/1/012025 ◽

2021 ◽

Vol 921 (1) ◽

pp. 012025

Author(s):

S Gusty ◽

M. Tumpu ◽

H Parung ◽

I Marzuki

Keyword(s):

Coarse Aggregate ◽

Asphalt Mixture ◽

Heavy Rain ◽

Plastic Waste ◽

Low Density ◽

Test Results ◽

Porous Asphalt ◽

Marshall Test ◽

Porous Pavement ◽

The Stability

Abstract Inundation due to heavy rain often disturbs traffic flow and porous pavement as a wearing course is one solution to overcome standing water. This asphalt mixture uses an open gradation which is dominated by coarse aggregate with an air cavity content ranging from 20% - 25%. In Indonesia, according to the Indonesian Solid Waste Association (2013), this type of plastic waste ranks second with 5.4 million tons per year and is ranked second in the world as a producer of marine plastic waste after China. This research tries to use plastic waste as an added material in the porous asphalt mixture where the gradation of porous asphalt refers to REAM Specifications, 2008. The type of plastic used is Low Density Polyethilene (LDPE). The levels of plastic waste used were 0%, 2%, 4%, 6%, 8% of the total weight of the mixture. Marshall and Cantabro characteristics tests were conducted to evaluate the resulting mixture. The results of this study indicate that the stability value meets the REAM specifications, namely 350 - 800 kg. Marshall test results with the use of LDPE plastic waste as an additive to the test object meet the characteristics of Marshall except for Marshall Quotient (MQ) and voids filled with bitumen (VFB).

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Underground Microseismic Event Monitoring and Localization within Sensor Networks

Sensors ◽

10.3390/s21082830 ◽

2021 ◽

Vol 21 (8) ◽

pp. 2830

Author(s):

Sili Wang ◽

Mark P. Panning ◽

Steven D. Vance ◽

Wenzhan Song

Keyword(s):

Sensor Networks ◽

Real Time ◽

Information Needs ◽

Localization Algorithm ◽

Distributed Sensors ◽

Distributed Sensor ◽

Microseismic Events ◽

The Stability ◽

Stability And Accuracy

Locating underground microseismic events is important for monitoring subsurface activity and understanding the planetary subsurface evolution. Due to bandwidth limitations, especially in applications involving planetarily-distributed sensor networks, networks should be designed to perform the localization algorithm in-situ, so that only the source location information needs to be sent out, not the raw data. In this paper, we propose a decentralized Gaussian beam time-reverse imaging (GB-TRI) algorithm that can be incorporated to the distributed sensors to detect and locate underground microseismic events with reduced usage of computational resources and communication bandwidth of the network. After the in-situ distributed computation, the final real-time location result is generated and delivered. We used a real-time simulation platform to test the performance of the system. We also evaluated the stability and accuracy of our proposed GB-TRI localization algorithm using extensive experiments and tests.

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Explicit parallel co-simulation approach: analysis and improved coupling method based on H-infinity synthesis

Multibody System Dynamics ◽

10.1007/s11044-021-09785-x ◽

2021 ◽

Author(s):

Weitao Chen ◽

Shenhai Ran ◽

Canhui Wu ◽

Bengt Jacobson

Keyword(s):

Frequency Domain ◽

Wide Frequency Range ◽

Coupling Method ◽

Sampled Data ◽

H Infinity ◽

First Case ◽

Communication Step ◽

Coupling Variables ◽

The Stability ◽

Stability And Accuracy

AbstractCo-simulation is widely used in the industry for the simulation of multidomain systems. Because the coupling variables cannot be communicated continuously, the co-simulation results can be unstable and inaccurate, especially when an explicit parallel approach is applied. To address this issue, new coupling methods to improve the stability and accuracy have been developed in recent years. However, the assessment of their performance is sometimes not straightforward or is even impossible owing to the case-dependent effect. The selection of the coupling method and its tuning cannot be performed before running the co-simulation, especially with a time-varying system.In this work, the co-simulation system is analyzed in the frequency domain as a sampled-data interconnection. Then a new coupling method based on the H-infinity synthesis is developed. The method intends to reconstruct the coupling variable by adding a compensator and smoother at the interface and to minimize the error from the sample-hold process. A convergence analysis in the frequency domain shows that the coupling error can be reduced in a wide frequency range, which implies good robustness. The new method is verified using two co-simulation cases. The first case is a dual mass–spring–damper system with random parameters and the second case is a co-simulation of a multibody dynamic (MBD) vehicle model and an electric power-assisted steering (EPAS) system model. Experimental results show that the method can improve the stability and accuracy, which enables a larger communication step to speed up the explicit parallel co-simulation.

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A Digital Framework to Predict the Sunshine Requirements of Landscape Plants

Applied Sciences ◽

10.3390/app11052098 ◽

2021 ◽

Vol 11 (5) ◽

pp. 2098

Author(s):

Heyi Wei ◽

Wenhua Jiang ◽

Xuejun Liu ◽

Bo Huang

Keyword(s):

Solar Radiation ◽

Plant Species ◽

Large Scale ◽

Normal Growth ◽

Adaptive Selection ◽

Landscape Plant ◽

Landscape Plants ◽

The Stability ◽

Stability And Accuracy ◽

The City

Knowledge of the sunshine requirements of landscape plants is important information for the adaptive selection and configuration of plants for urban greening, and is also a basic attribute of plant databases. In the existing studies, the light compensation point (LCP) and light saturation point (LSP) have been commonly used to indicate the shade tolerance for a specific plant; however, these values are difficult to adopt in practice because the landscape architect does not always know what range of solar radiation is the best for maintaining plant health, i.e., normal growth and reproduction. In this paper, to bridge the gap, we present a novel digital framework to predict the sunshine requirements of landscape plants. First, the research introduces the proposed framework, which is composed of a black-box model, solar radiation simulation, and a health standard system for plants. Then, the data fitting between solar radiation and plant growth response is used to obtain the value of solar radiation at different health levels. Finally, we adopt the LI-6400XT Portable Photosynthetic System (Li-Cor Inc., Lincoln, NE, USA) to verify the stability and accuracy of the digital framework through 15 landscape plant species of a residential area in the city of Wuhan, China, and also compared and analyzed the results of other researchers on the same plant species. The results show that the digital framework can robustly obtain the values of the healthy, sub-healthy, and unhealthy levels for the 15 landscape plant species. The purpose of this study is to provide an efficient forecasting tool for large-scale surveys of plant sunshine requirements. The proposed framework will be beneficial for the adaptive selection and configuration of urban plants and will facilitate the construction of landscape plant databases in future studies.

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