Controlling Thermal Properties of Asphalt Concrete and its Multifunctional Applications

Controlling infrastructure temperature, especially flexible pavement, has attracted attention in both industrial and academic societies because: 1) material properties of asphalt, and corresponding structural responses and distresses are temperature dependent and 2) pavement surface temperature directly relates to various environmental or safety problems. This study investigates the feasibility of mitigating the temperature-related problems of civil infrastructures (especially asphalt pavement) by controlling thermal properties of the construction materials. To change thermal properties of asphalt concrete, expanded polypropylene (EPP) pellet and graphite were selected as the additives and mixed into asphalt concrete. Experimental tests are classified into two categories: 1) physical and thermal characterizations of raw materials including Scanning Electron Microscope and heat susceptibility tests, and 2) mechanical and thermal properties of the modified asphalt mixtures via indirect tensile test and hot disk test, respectively. The heat susceptibility test results show that use of EPP as an aggregate replacement is a better choice than the use of the melted-EPP as a binder modifier because it has a good heat susceptibility and is hard to melt at the HMA working temperature. The mechanical performances and thermal properties evaluation results show that by replacing the aggregate with EPP to have 18% by volume of total mixture, the indirect tensile strength was reduced by 17%, and the thermal conductivity and volumetric heat capacity decreased by 32% and 27%, respectively. By adding 4.8 vol. % of graphite, the indirect tensile strength decreased by 20%, and an increase of 43% in thermal conductivity was obtained. To simulate the effect of the thermally modified asphalt mixtures on the surface temperature of pavements and bridges, a series of heat transfer analysis were conducted using the finite difference heat transfer model. In addition, a case study of a building using EPP modified cement concrete was carried out to investigate the benefits of EPP modified concrete as a wall insulation. From the simulation results, it is concluded that adding graphite into asphalt mixture mitigates the urban heat island effect during summer by dropping the maximum surface temperatures of both pavement and bridge (3.1ºC and 1.9ºC, respectively, with 4.8% graphite), and the graphite modified asphalt concrete can reduce the use of deicing agents during winter by increasing the minimum surface temperature by 0.5ºC for pavement and 0.2ºC for bridge. On the other hand, adding EPP increases maximum surface temperature by 0.8ºC for pavement and 1.0ºC for bridge during winter, which show the potential for snow and ice removal application. In addition, the simulation shows that the EPP modified concrete can serve as a wall insulator

Stability analysis of differential scheme for dynamic equations of mooring cable system

The mooring cable system in plane motion can be modeled as two coupled partial differential equations, which can be numerical solved by finite difference method directly. The difference scheme is analyzed, and parameters selection for time-marching of displacement and velocity are deduced. The stability condition of the scheme is analyzed through Fourier series method, and parameters range which match stable scheme is given. Then, the parameters range is verified by a numerical example

Galloping behavior analysis of transmission line with thin ice accretions

A dynamic model of a galloping transmission line able to describe for the coupling of its longitudinal, in-plane, out-of-plane and torsional vibrations is established. It also considers the effects of geometrical nonlinearity and aerodynamic nonlinearity. By the static configuration, the reduced model is obtained. Then, the equations of motion are obtained through the Galerkin method. It contains two in-plane, two out-of-plane and two torsional components. By numerical calculation, the maximum amplitudes at wind speeds are drawn and the galloping behavior of transmission line with thin ice accretions is analyzed. The obtained results show that the second galloping mode is more triggered. The double-mode galloping occurs in all motions, in which the maximum amplitude is bigger than in single-mode galloping. And the double-mode galloping presents the track of inclined ‘8’ in longitudinal direction

RECYCLING AND REUSE OF MATERIALS IN TRANSPORTATION PROJECTS —CURRENT STATUS AND POTENTIAL OPPORTUNITIES INCLUDING EVALUATION OF RCA CONCRETE PAVEMENTS ALONG AN OKLAHOMA INTERSTATE HIGHWAY (FHWA-OK-18-04)

Oklahoma Department of Transportation (ODOT) is committed to protect and enhance human and natural environment while developing a safe, economical, and effective transportation system. The first objective of this research was to evaluate the availability of the recycled materials and develop strategies for increasing use of recycled materials in ODOT transportation construction projects. In this objective, an extensive literature search was conducted to acquire information pertaining to properties, current practices, and available field investigations of the commonly used recycled materials. Use of recycled concrete aggregate in concrete paving mixtures (RCA-CPM) was determined to be the major focus in this research as applications of RCA-CPM by ODOT and other DOTs have been reported as a sustainable and durable construction practice. Subsequently, a review of the key findings pertaining to RCA material properties and effects of RCA on portland cement concrete pavement (PCCP) performance was performed. Additionally, a life cycle assessment addressing all the three aspects of sustainability (i.e., economic, social, and environmental) was performed to do a comparative assessment between RCA-PCCP and plain PCCP and project the benefits of using RCA-CPM. The second objective was to evaluate the long-term performance of existing PCCP made with RCA in Oklahoma. A jointed plain concrete pavement (JPCP) and a continuously reinforced concrete pavement (CRCP) section were selected and evaluated through various tests covering different aspects, which includes visual survey, determination of mechanical properties, petrographic examination, and evaluation of the existing base through falling weight deflectometer (FWD). From the lab and field studies, it was verified that good base support, strong load transfer, and shorter joint spacing are essential design considerations for JPCP made of RCA-PCC. CRCP using effective anti-corrosion measures might be more suitable for implementing RCA-PCC; CRCP could better protect the base from erosion caused by higher differential energy and help restrain high drying and thermal volume change of RCA-PCC.Final Report October 2016-September 2018N

SGDP: A Stream-Graph Neural Network Based Data Prefetcher

Data prefetching is important for storage system optimization and access performance improvement. Traditional prefetchers work well for mining access patterns of sequential logical block address (LBA) but cannot handle complex non-sequential patterns that commonly exist in real-world applications. The state-of-the-art (SOTA) learning-based prefetchers cover more LBA accesses. However, they do not adequately consider the spatial interdependencies between LBA deltas, which leads to limited performance and robustness. This paper proposes a novel Stream-Graph neural network-based Data Prefetcher (SGDP). Specifically, SGDP models LBA delta streams using a weighted directed graph structure to represent interactive relations among LBA deltas and further extracts hybrid features by graph neural networks for data prefetching. We conduct extensive experiments on eight real-world datasets. Empirical results verify that SGDP outperforms the SOTA methods in terms of the hit ratio by 6.21%, the effective prefetching ratio by 7.00%, and speeds up inference time by 3.13X on average. Besides, we generalize SGDP to different variants by different stream constructions, further expanding its application scenarios and demonstrating its robustness. SGDP offers a novel data prefetching solution and has been verified in commercial hybrid storage systems in the experimental phase. Our codes and appendix are available at https://github.com/yyysjz1997/SGDP/

New Yuomys rodents from southeastern Qinghai-Tibet Plateau indicate low elevation during the Middle Eocene

Yuomys are medium-sized Hystricomorpha rodents. They are known for coming from areas of low elevation in China during the middle and late Eocene. Two new Yuomys were discovered from a locality near Xueshuo village in Litang County, Sichuan Province. The locality lies in the Gemusi pull-apart basin formed in the Litang Fault System (LTFS) in the Hengduan Mountains. The current average elevation is about 4200 m. One of the two new Yuomys is larger and shows clear lophodont and unilateral hypsodont morphology, similar to Yuomys yunnanensis, which was discovered as being from the early middle Eocene (Irdinmanhan, Asian Land Mammal Ages) in the Chake Basin of Jianshui County, Yunnan Province. The Chake Basin is one of the small pull-apart basins formed in the Xianshuihe-Xiaojiang Fault system (XSH-XJF). The other new Yuomys rodent is smaller, brachydont, and less lophodont than the larger new species. The small new Yuomys is smaller than all known Yuomys except Yuomys huheboerhensis, which is from the early middle Eocene Irdinmanhan of Inner Mongolia in Northern China. Given their narrow biochronological distribution and presumably preferred living environment, the occurrence of Yuomys in the pull-apart basins in LTFS and XSH-XJF suggests that the two deep fault systems probably started strike-slip movement by the early middle Eocene, about 49–45 million years ago. Well-studied middle Eocene mammalian faunas from Henan and Inner Mongolia include Yuomys, primates, and other low elevation forest mammals. We suggest that the two new Yuomys species reported here probably also lived in a similar low elevation forest environment

Optimum design and research on novel vehicle hybrid excitation synchronous generator

Hybrid excitation is an organic combination of permanent magnet excitation and electric excitation. Hybrid excitation synchronous generator (HESG) both has the advantages of light quality, less losses and high efficiency like permanent magnet generator and the advantages of good magnetic field adjusting performance like electric excitation generator, so it is very suitable for the vehicle application. This paper presented a novel vehicle HESG which has skew stator core, permanent magnet rotor and both armature winding and field winding in the stator. Using ANSYS software, simulating the electric excitation field and the magnetic field, and finally the main parameters of HESG were designed. The simulation and the test results both show that the novel vehicle PMSG has the advantages of small cogging torque, high efficiency, small harmonic component output voltage and low waveform aberration, so as to meet the design requirements fully

Analysis of Long Noncoding RNAs in Aila-Induced Non-Small Cell Lung Cancer Inhibition

Non-small cell lung cancer (NSCLC) has the highest morbidity and mortality among all carcinomas. However, it is difficult to diagnose in the early stage, and current therapeutic efficacy is not ideal. Although numerous studies have revealed that Ailanthone (Aila), a natural product, can inhibit multiple cancers by reducing cell proliferation and invasion and inducing apoptosis, the mechanism by which Aila represses NSCLC progression in a time-dependent manner remains unclear. In this study, we observed that most long noncoding RNAs (lncRNAs) were either notably up- or downregulated in NSCLC cells after treatment with Aila. Moreover, alterations in lncRNA expression induced by Aila were crucial for the initiation and metastasis of NSCLC. Furthermore, in our research, expression of DUXAP8 was significantly downregulated in NSCLC cells after treatment with Aila and regulated expression levels of EGR1. In conclusion, our findings demonstrate that Aila is a potent natural suppressor of NSCLC by modulating expression of DUXAP8 and EGR1