scholarly journals Effect of the Compactness on the Texture and Friction of Asphalt Concrete Intended for Wearing Course of the Road Pavement

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 192
Author(s):  
Tengda Wang ◽  
Liqun Hu ◽  
Xiaodong Pan ◽  
Song Xu ◽  
Di Yun
Keyword(s):  
Surface Texture ◽  
Asphalt Concrete ◽  
High Speed ◽  
Three Dimensional ◽  
Polishing Process ◽  
Road Pavement ◽  
3D Texture ◽  
3D Surface Topography ◽  
Friction Performance ◽  
The Impact

Maintaining good friction performance of highway pavement is important for road safety. The friction is affected by many factors, and the present study investigates the effect of the compactness on the texture and friction of asphalt concrete during the polishing process. Two three-dimensional (3D) texture parameters and the mean texture depth (MTD) were used to characterize the surface texture of AC-13 asphalt concrete. The differences of surface texture are then being analyzed among the pavement in the field, rutting slabs with 97% compactness (RS-97), rutting slabs with 100% compactness (RS-100), and rutting slabs with 103% (RS-103). The rutting slabs were polished by a circular vehicle simulator (CVS). The 3D surface topography, British pendulum number (BPN), and MTD were obtained during the polishing process. Test results show that the surface of the rutting slab can be smoother as the compactness increased from 97% to 103%. During the whole polishing process, the rutting slab with smaller compactness had higher value of the MTD. The impact of compactness on the BPN is insignificant during the polishing process, but rutting slabs with smaller compactness had better friction at high speed as the result of the higher MTD.

scholarly journals Pengaruh Penambahan Limbah Plastik Jenis Thermosetting Terhadap Parameter Marshall Laston AC-WC

2019 ◽  
Vol 24 (2) ◽  
pp. 166
Author(s):  
Kusdiyono Kusdiyono ◽  
Supriyadi Supriyadi ◽  
Tedjo Mulyono ◽  
Sukoyo Sukoyo
Keyword(s):  
Asphalt Concrete ◽  
Plastic Waste ◽  
Concrete Mixture ◽  
Partial Replacement ◽  
Short Term ◽  
Road Pavement ◽  
Long Run ◽  
Plastic Bag ◽  
Marshall Stability ◽  
The Impact

At present, plastic is a material that is needed by the community at large, where the impact is also very extraordinary after the plastic is used in everyday life which can cause serious problems if the management is not done properly. The problem of plastic waste does not only occur in the city of Semarang, but also in other cities, so that the Ministry of Environment and Forestry has implemented a paid plastic bag program in the short term. But this is only to deal with problems in the short term. In the long run, it will not solve the problem of "plastic waste", because the policy actually encourages people to buy plastic which, of course, will add a new burden for the community to buy it. Based on the above problems, it is necessary to utilize this plastic waste to be made into road pavement materials such as in the manufacture of Asphal Concrette Wearing Course, by making 5 mixed variations ranging from (2 to 10)% of the weight of the aggregate . This research was initiated through a survey process, material procurement, testing of stacking materials, making test specimens, testing specimens. The results of the research can show that the type of Thermosetting plastic waste has a significant influence on the Asphalt Concrete mixture AC-WC heat mixture, including: Density, Marshall Stability, Flow, VIM, VMA, MQ and the remaining Marshall Stability tend to show an increase, moderate VFA and VIMrefusal Density values tend to show a decrease. Thus the plastic waste from the Thermosetting type can be used as a partial replacement of the aggregate for the Asphalt Concrete mixture AC-WC heat mixture with a plastic waste content is limited to a maximum of 10% and at an optimum asphalt content of 5.55%. Thus this research is expected to be of benefit to the industry and the people of Semarang in relation to the use of plastic waste for road pavement.

The effect analysis of an engine jet on an aircraft blast deflector

2018 ◽  
Vol 41 (4) ◽  
pp. 990-1001
Author(s):  
Song Ma ◽  
Jianguo Tan ◽  
Xiankai Li ◽  
Jiang Hao
Keyword(s):  
High Temperature ◽  
Flow Field ◽  
High Speed ◽  
Deflection Angle ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
Experimental Results ◽  
Exhaust Gases ◽  
The Impact

This paper establishes a novel mathematical model for computing the plume flow field of a carrier-based aircraft engine. Its objective is to study the impact of jet exhaust gases with high temperature, high speed and high pressure on the jet blast deflector. The working condition of the nozzle of a fully powered on engine is first determined. The flow field of the exhaust jet is then numerically simulated at different deflection angle using the three-dimensional Reynolds averaged Navier–Stokes equations and the standard [Formula: see text]-[Formula: see text] turbulence method. Moreover, infra-red temperature tests are further carried out to test the temperature field when the jet blast deflector is at the [Formula: see text] deflection angle. The comparison between the simulation results and the experimental results show that the proposed computation model can perfectly describe the system. There is only 8–10% variation between them. A good verification is achieved. Moreover, the experimental results show that the jet blast deflector plays an outstanding role in driving the high-temperature exhaust gases. It is found that [Formula: see text] may be the best deflection angle to protect the deck and the surrounding equipment effectively. These data results provide a valuable basis for the design and layout optimization of the jet blast deflector and deck.

Laser Scan System to Establish 3-D Surface Texture and Predict Friction of Pavement

2011 ◽  
Vol 145 ◽  
pp. 339-343 ◽  
Author(s):  
Shih Huang Chen ◽  
Ching Tsung Hung ◽  
Chang Hua Yu ◽  
Hung Wen Chung ◽  
Chia Hao Chen
Keyword(s):  
Surface Texture ◽  
Asphalt Concrete ◽  
Correlation Coefficients ◽  
High Definition ◽  
Porous Asphalt ◽  
3D Texture ◽  
Key Factor ◽  
Stone Mastic Asphalt ◽  
Computer Simulation Program ◽  
The Relationship

Friction of pavement is the most popular tropic which is concerned by drivers and engineers, surface texture are also widely regarded as key factor to influence it. The brief object of this study is to establish the relationship between 3 D texture and friction. In the study, the mixtures include Dense Grade Asphalt Concrete (DGAC), Stone Mastic Asphalt (SMA), and Porous Asphalt (PA). High Definition Scan Texture Machine (HDSTM) with 2D Laser CCD was adopted to measure the 2 D texture of Asphalt concrete specimens, and British Portable Tester (BPN) was also used to evaluate friction of various mixture specimen surfaces. The study was attempted to further create initial 3 D model with data of HDSTM and Computer Simulation Program. Correlation coefficients between the ratio of Surface area in unit area (SA/A) and friction was up to 0.8. SA/A could be regards as the best feasible factor to estimate the mixture surface in the ability of skid resistance, and. Based on above results, 3D texture parameter is remarkable for evaluation of friction and is was worthy of further study.

Impact Energy Measurement of a Hydraulic Breaker

2006 ◽  
Vol 326-328 ◽  
pp. 1669-1672
Author(s):  
Jong Won Park ◽  
Hyoung Eui Kim
Keyword(s):  
Construction Industry ◽  
Impact Energy ◽  
High Speed ◽  
Test System ◽  
Hydraulic Power ◽  
Construction Machinery ◽  
Road Pavement ◽  
Hydraulic Cylinders ◽  
The Impact ◽  
Test Process

A hydraulic breaker for construction machinery generally used for the destroying and disassembling of buildings, crashing road pavement, breaking rocks at quarry and so on. So the measurement of the impact energy of a hydraulic breaker is very important thing to prove its capability to manufacturers and customers. In this study, the test system for measuring the impact energy of a hydraulic breaker was designed and constructed. The test system was consisted with hydraulic cylinders for mounting a breaker, impact absorbing base and frames, pressure and flow sensors, high speed and accurate data acquisition system diesel engine driven hydraulic power unit. The test process of the developed system was carried by measuring guide for tool energy rating for hydraulic breakers which was developed by the CIMA (Construction Industry Manufacturers Association) USA. The developed test system can be applied to measure the impact energy for various kinds of hydraulic breakers.

scholarly journals Impacts of a railway tunnel on the streams baseflow verified by means of numerical modelling

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Leonardo Piccinini ◽  
Valentina Vincenzi
Keyword(s):  
Numerical Modelling ◽  
High Speed ◽  
Three Dimensional ◽  
Tracer Tests ◽  
Maximum Flow ◽  
Mitigation Strategies ◽  
Railway Tunnel ◽  
Flow Measurements ◽  
Railway Line ◽  
The Impact

The high-speed railway line between Bologna and Florence (Italy) is mostly developed underground through the Tuscan-Emilian Apennine, and the tunnels severely impacted groundwater and surface water. The 15-km-long Firenzuola tunnel crosses siliciclastic turbidites: during drilling, water inrushes occurred at fault and fracture zones, and the tunnel continues to drain the aquifer. The water table dropped below the level of the valleys, and gaining streams transformed into losing streams or ran completely dry, as did many springs. Hydrological observations and two multitracer tests have previously characterized the stream-tunnel connections and the impact processes. In the framework of planning mitigation strategies to minimize impacts on stream baseflow, three-dimensional numerical modelling with MODFLOW (the EPM approach) is applied to evaluate the artificial minimum flow needed to maintain flow continuity along the stream during the recession phase. The establishment of the two presented models is based on hydrogeological monitoring data and the results of flow measurements and tracer tests. Maximum flow rates subtracted from stream baseflow by the tunnel along the connection structures are calculated for two streams with major impacts.

A modified Fresnel-based algorithm for 3D microwave imaging of metal objects

2018 ◽  
Vol 11 (4) ◽  
pp. 313-325
Author(s):  
Farshad Zamiri ◽  
Abdolreza Nabavi
Keyword(s):  
High Speed ◽  
Fourier Transforms ◽  
Low Cost ◽  
Three Dimensional ◽  
Computation Time ◽  
Microwave Imaging ◽  
Reconstruction Algorithms ◽  
Clock Frequency ◽  
Pipeline Architecture ◽  
The Impact

AbstractMicrowave holography technique reconstructs a target image using recorded amplitudes and phases of the signals reflected from the target with Fast Fourier Transform (FFT)-based algorithms. The reconstruction algorithms have two or more steps of two- and three-dimensional Fourier transforms, which have a high computational load. In this paper, by neglecting the impact of target depth on image reconstruction, an efficient Fresnel-based algorithm is proposed, involving only one-step FFT for both single- and multi-frequency microwave imaging. Numerous tests have been performed to show the effectiveness of the proposed algorithm including planar and non-planar targets, using the raw data gathered by means of a scanner operating in X-band. Finally, a low-cost and high-speed hardware architecture based on fixed-point arithmetic is introduced which reconstructs the planar targets. This pipeline architecture was tested on field programmable gate arrays operating at 200 MHz clock frequency, which illustrates more than 30 times improvement in computation time compared with a computer.

Lumped Capacitance and 3D CFD Conjugate Heat Transfer Modelling of an Automotive Turbocharger

2015 ◽  
Author(s):  
R. Burke ◽  
C. Copeland ◽  
T. Duda ◽  
M. A. Reyes-Belmonte
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Weak Link ◽  
Three Dimensional ◽  
Sensitivity Study ◽  
Heat Fluxes ◽  
Strategy Development ◽  
Inlet Temperature ◽  
Compression Process ◽  
The Impact

One dimensional wave-action engine models have become an essential tool within engine development including stages of component selection, understanding system interactions and control strategy development. Simple turbocharger models are seen as a weak link in the accuracy of these simulation tools and advanced models have been proposed to account for phenomena including heat transfer. In order to run within a full engine code, these models are necessarily simple in structure yet are required to describe a highly complex 3D problem. This paper aims to assess the validity of one of the key assumptions in simple heat transfer models, namely, that the heat transfer between the compressor casing and intake air occurs only after the compression process. Initially a sensitivity study was conducted on a simple lumped capacity thermal model of a turbocharger. A new partition parameter was introduced αA, which divides the internal wetted area of the compressor housing into pre and post compression. The sensitivity of heat fluxes to αA was quantified with respect to the sensitivity to turbine inlet temperature (TIT). At low speeds, the TIT was the dominant effect on compressor efficiency whereas at high speed αA had a similar influence to TIT. However, modelling of the conduction within the compressor housing using an additional thermal resistance caused changes in heat flows of less than 10%. Three dimensional CFD analysis was undertaken using a number of cases approximating different values of αA. It was seen that when considering a case similar to αA=0, meaning that heat transfer on the compressor side is considered to occur only after the compression process, significant temperature could build up in the impeller area of the compressor housing, indicating the importance of the pre-compression heat path. The 3D simulation was used to estimate a realistic value for αA which was suggested to be between 0.15 and 0.3. Using a value of this magnitude in the lumped capacitance model showed that at low speed there would be less than 1% point effect on apparent efficiency which would be negligible compared to the 8% point seen as a result of TIT. In contrast, at high speeds, the impact of αA was similar to that of TIT, both leading to approximately 1% point apparent efficiency error.

The Study of Enhanced Mechanical Properties for Cu/Gr/2024Al Composite

2022 ◽  
Vol 905 ◽  
pp. 254-262
Author(s):  
Feng Guo Liu ◽  
Ya Nan Zhang ◽  
Hao Chen ◽  
Si Cheng Li ◽  
Ren Guo Guan
Keyword(s):  
Matrix Material ◽  
Three Dimensional ◽  
Alloy Matrix ◽  
Mixed Powder ◽  
Binding Interface ◽  
Tissue Hardness ◽  
Graphene Content ◽  
Friction Performance ◽  
Modified Graphene ◽  
The Impact

2024Al alloy powder as matrix material with nanocopper-modified graphene as reinforcement was studied to explore the effects of graphene on the tissue, hardness, friction performance of the composite. The Cu/Gr/2024Al composites were prepared via three-dimensional mixed powder and vacuum hot press sintering. The results found that the nanocopper-modified graphene could be uniformly distributed in the aluminum alloy matrix, and formed a good binding interface with the matrix material. When the graphene content was 0.75 wt.% and 1.0wt%, the impact yield strength and the hardness reached the maximum of 434.8 MPa and 118.4 HV5, which were 27.24% and 43.11% higher than that of 2024Al respectively. Furthermore, with the increase of nanocopper-modified graphene content, the corrosion resistance of composite materials in 3.5%Cl-concentration solution was improved.

scholarly journals Evaluation of the Potential Electromagnetic Interference in Vertically Stacked 3D Integrated Circuits

2020 ◽  
Vol 10 (3) ◽  
pp. 748
Author(s):  
Dipesh Kapoor ◽  
Cher Ming Tan ◽  
Vivek Sangwan
Keyword(s):  
Integrated Circuits ◽  
Integrated Circuit ◽  
Electromagnetic Interference ◽  
High Speed ◽  
High Performance ◽  
Near Field ◽  
Three Dimensional ◽  
3D Ic ◽  
Three Dimensional Integrated Circuit ◽  
The Impact

Advancements in the functionalities and operating frequencies of integrated circuits (IC) have led to the necessity of measuring their electromagnetic Interference (EMI). Three-dimensional integrated circuit (3D-IC) represents the current advancements for multi-functionalities, high speed, high performance, and low-power IC technology. While the thermal challenges of 3D-IC have been studied extensively, the influence of EMI among the stacked dies has not been investigated. With the decreasing spacing between the stacked dies, this EMI can become more severe. This work demonstrates the potential of EMI within a 3D-IC numerically, and determines the minimum distance between stack dies to reduce the impact of EMI from one another before they are fabricated. The limitations of using near field measurement for the EMI study in stacked dies 3D-IC are also illustrated.

scholarly journals The impact of pelvic lateral rotation on hindlimb kinematics and stride length in the red-legged running frog, Kassina maculata

2019 ◽  
Vol 6 (5) ◽  
pp. 190060 ◽  
Author(s):  
Amber J. Collings ◽  
Laura B. Porro ◽  
Cameron Hill ◽  
Christopher T. Richards
Keyword(s):  
High Speed ◽  
Stride Length ◽  
Reference Frames ◽  
Comparative Anatomy ◽  
Three Dimensional ◽  
Video Data ◽  
The Body ◽  
Kinematic Models ◽  
Lateral Rotation ◽  
The Impact

Some frog species, such as Kassina maculata (red-legged running frog), use an asynchronous walking/running gait as their primary locomotor mode. Prior comparative anatomy work has suggested that lateral rotation of the pelvis improves walking performance by increasing hindlimb stride length; however, this hypothesis has never been tested. Using non-invasive methods, experimental high-speed video data collected from eight animals were used to create two three-dimensional kinematic models. These models, each fixed to alternative local anatomical reference frames, were used to investigate the hypothesis that lateral rotation of the mobile ilio-sacral joint in the anuran pelvis plays a propulsive role in walking locomotion by increasing hindlimb stride length. All frogs used a walking gait (duty factor greater than 0.5) despite travelling over a range of speeds (0.04–0.23 m s −1 ). The hindlimb joint motions throughout a single stride were temporally synchronized with lateral rotation of the pelvis. The pelvis itself, on average, underwent an angular excursion of 12.71° (±4.39°) with respect to the body midline during lateral rotation. However, comparison between our two kinematic models demonstrated that lateral rotation of the pelvis only increases the cranio-caudal excursion of the hindlimb modestly. Thus, we propose that pelvic lateral rotation is not a stride length augmenting mechanism in K. maculata .

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