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To evaluate rutting based on driving quality of vehicles, three pavement models were established in view of the morphological characteristic of pavement ruts and friction coefficients, and the control models of vehicles conducting the braking were established according to different driving conditions. Lateral acceleration, roll angle, yaw angle, and lateral offset were adopted to describe the driving quality and safety of vehicles. The effects of different rut depths and width–height ratios on driving quality of vehicles under different driving conditions were analyzed. Results show that when a vehicle drives across a rut on a dry pavement at a speed of 100 km/h, the rut depth should be less than 20 mm to ensure the driving stability of vehicle. Road engineers and researchers should pay attention to this situation that width-height ratios of sidewall are 1 or smaller. When one wheel of a vehicle is braked in a rut groove with water, the driving speed of vehicles should be strictly controlled within 120 km/h, and the rut depth for road with a high driving speed should be less than 10 mm to ensure the driving stability and safety. The presented findings may make a contribution to maintenance decision-making.

Addition of fibres has been recently studied as an effective method to enhance soil. To investigate the reinforcing effect of fibres on the shear strength of soil, polypropylene fibres are added in...

The yellow tip butterfly Anthocharis scolymus (Lepidoptera: Pieridae) has a circular mitochondrial genome of 15,230 bp in size. It consists 13 protein-coding genes, 22 tRNAs, two ribosomal RNA genes, and an AT-rich control region. Using whole mitogenome alignments, we reconstructed the phylogenetic relationships of 28 pierid butterflies. The maximum-likelihood (ML) tree topology was consistent with previous studies.

Stress-absorption interlayer (SAI) is one of the most important methods to prevent reflection cracking. This paper analyzed the properties of SAI with the waste tire rubber (WTR) and amorphous ploy alpha olefin (APAO) complex modified asphalt binder. Research found that WTR/APAO modified asphalt works excellently as a binder in SAI. The SAI with base asphalt, WTR/APAO, WTR and SBS modified asphalt mixture were prepared for comparative analysis. The mechanical properties and durability of four SAIs were determined using Marshall stability, Indirect tensile (IDT) strength, immersion Marshall and Marshall stability after aging procedure. The bond strength and shear resistance of three SAIs with modified asphalt were determined using slant shear tests under different conditions. The overlay tests (OT) were used to characterize the fatigue and anti-reflection cracking performance. Besides, the Paris’ Law was used to characterize the fracture properties based on OT. Research found that WTR/APAO SAI had the strongest high temperature stability, deformation resistance, bond strength and shear resistance. WTR/APAO and SBS SAIs had excellent water stability and anti-aging performance. WTR/APAO SAI had the highest bond strength at both high and normal temperatures. The OT number of cycles of all three SAIs reached 1200 times. This indicator showed that all three SAIs had excellent fatigue and anti-reflection cracking performance. Further research found that the fracture properties n in Paris’ Law showed that WTR/APAO and SBS SAIs had better cracking resistance. The addition of APAO improved the cracking resistance of WTR SAI.

In this paper, the proposed millimeter-wave voltage controlled oscillator (VCO) is based on Class-F oscillator and adopts the design of multi-peak transformer to enhance the third harmonic so as to obtain higher frequency and lower phase noise. A high frequency millimeter wave VCO is realized by the design of a low frequency resonator. As a result, the VCO has lower phase noise and lower power consumption while obtaining wider frequency tuning range than traditional mm-Wave VCOs. In addition, a broadband buffer with a low-k m transformer which can suppress the first-harmonic and extract the third-harmonic is proposed. Simulated results show that the proposed VCO exhibits phase noise of -93.6~-95.1dBc/Hz at 1 MHz offset at 72.8~90.1 GHz, and the DC power consumption of the VCO core is only 10.8mW at the supply voltage of 0.9V.

A millimeter wave wideband digitally controlled oscillator in 40nm CMOS technology is presented in this paper that spans a frequency range from 58.5 to 74.4GHz. The wideband operation is achieved by an on-chip transformer controlled by mutual inductance switching to obtain low and high frequency bands. Moreover, discrete capacitor tuning is achieved by using discrete voltage control variable capacitors without introducing switches, which greatly reduces parasitic capacitance and losses. Finally, an output buffer structure with high isolation is implemented to ensure the excellent output characteristics of this oscillator. The phase noise range at 1MHz frequency offset from 91 to -95dBc/Hz and the chip area is only 0.053mm2 with 23.9% frequency tuning ratio.

Fracturing behavior of rock is significantly affected by water. To study the influence of water on the critical values of stress intensity factors (the SIFc, including KIf and KIIf) corresponding to the onset of fracture of rocks, edge-cracked semicircular bend (SCB) testing was performed on sandstone specimens (collected at a site in Linyi City, Shandong Province, China) with different water contents. First, water absorption was tested to study the evolution of the water content in the specimens. Then, the SIFc of SCB specimens after different soaking durations in water (yielding conditions ranging from dry to saturation) was tested under three-point loading. The results showed a linear decrease in SIFc with increasing water content for all the specimens with different notch angles; however, with increasing notch angle, the KIf exponentially decreased, while the KIIf increased. To study the effect of sustained load on SIFs of rock in water, a new experiment was designed on the specimen subjected to loading while soaking for a certain duration, then the SIFc was tested. Comprehensive predictive empirical relationships are established between SIFc and water content/soaking duration for the sandstone. A novel observation is for two specimens with the same water soaking duration, the SIFc of a specimen with loading during soaking is lower than that when it was tested after soaking, which is attributed to the fact that water is more likely to penetrate into the rock, because the bending load opens pores and cracks then leads to an increase in water content under such conditions. In other words, the water content of sandstone specimens used in this study is the key factor affecting its SIFc.

Structural health monitoring (SHM) is a challenge for many industries. Over the last decade, novel strain monitoring methods using optical fibers have been implemented for SHM in aerospace, energy storage, marine, and civil engineering structures. However, the practical attachment of optical fibers (OFs) to the component is still problematic. While monitoring, the amount of substrate strain lost by the OF attachment is often unclear, and difficult to predict under long-term loads. This investigation clarifies how different attachment methods perform under time-dependent loading. Optical fibers are attached on metal, thermoset composite, and thermoplastic substrates for distributed strain sensing. Strains along distributed optical fiber sensors (DOFS) are measured by optical backscatter reflectometry (OBR) and compared to contact extensometer strains under tensile creep loading. The quality of the bondline and its influence on the strain transfer is analyzed. Residual strains and strain fluctuations along the sensor fiber are correlated to the fiber attachment method. Results show that a machine-controlled attachment process (such as in situ 3-D printing) holds great promise for the future as it achieves a highly uniform bondline and provides accurate strain measurements.

The silver-studded blue butterfly Plebejus argus (Lepidoptera: Lycaenidae) has a mitochondrial genome of 15,426 bp. It consists 13 protein-coding genes, 23 tRNAs with an extra copy of tRNASer, two ...

Oeneis urda (Eversmann, 1847) is a butterfly of the Satyrinae (Lepidoptera: Nymphalidae) and a member of the Arctics, which are distributed in the arctic, subarctic, or high-altitude alpine regions...

Low-illumination images are generally low-quality images. The retinex algorithm can cause halo artifacts and loss of details in processing. Therefore, an improved Retinex algorithm is proposed. Firstly, the HSI color space which is more in line with the human visual characteristics is selected instead of the RGB image, that is, the luminance component I is processed. Then, the illuminance image is estimated by using a guided filter that fuses the edge detection operator, and the edge detection operator can be better positioned. At the edge, an illuminance image with rich edge information can be obtained; after obtaining the illuminance image, the reflected image can be obtained by the Retinex principle, the obtained reflected image is subjected to low-rank decomposition, and the low-rank property of the image is used to suppress the enlarged halo and the enhancement process. Noise; finally, the visual effect is further improved by local contrast enhancement. Experiments show that the algorithm can effectively improve the brightness and contrast of the image, preserve the details of the image, and also suppress the noise interference in the enhancement process. The subjective visual effect and objective evaluation results of the image have also been greatly improved.

As an essential part of the pavement maintenance management system, preventive maintenance plays an important role in the asphalt pavement maintenance decision-making. In order to compare long-term effectiveness of preventive maintenance treatments (PMTs) under various environmental conditions, Specific Pavement Studies-3 (SPS-3) data were extracted from Long-Term Pavement Performance (LTPP) program in this study. Environmental conditions include climate, traffic level and pre-treatment pavement condition. Weighted distress was used to characterize an average long-term performance. An average increment indicator was proposed to qualitatively analyze the effects of these conditions on the effectiveness of treatments. Logistic regression was adopted to quantity these effects. Implementation proposals were recommended in terms of PMTs. Results show that thin overlay is the most effective in comprehensive treatment of all performances, followed by chip seal, slurry seal and crack seal. Freeze condition has a significant influence on the effectiveness of treatments. Moisture level significantly influenced rutting and transverse cracking. Traffic level is a main factor for the effectiveness of treatments on roughness, longitudinal cracking and alligator cracking. The effects of pre-treatment pavement condition on only roughness and rutting are significant. The proposed average increment indicator allows to assess the long-term effectiveness of PMTs and the influence of different factors.

The aging resistance of asphalt mixture has an important impact on the long-term quality and service life of asphalt pavements. This research aims at studying the effects of long-term aging on waste tire rubber (WTR) and amorphous poly alpha olefin (APAO) modified asphalt binder and mixtures. The prepared compounds included, 12%WTR + 4%APAO and 15%WTR + 4%APAO modified asphalts, were used as experimental objects. Base asphalt binder (70 penetration grade), 15%WTR modified asphalt and styrene–butadiene-styrene (SBS) modified asphalt were the reference objects. First, pressure aging vessel (PAV) and long-term oven aging (LTOA) were used to simulate the long-term aging of asphalt binder and mixture, respectively. Secondly, the performance tests of asphalt binder and mixture were carried out, and the evaluation indexes of the effects of long-term aging on performance were proposed. For the asphalt binder, the results show that the incorporation of WTR and APAO significantly improves the post-aging conventional properties, rheological properties and fatigue properties. The Fourier transform infrared spectroscopy (FTIR) results were found to correlate to the physical tests results. In the asphalt mixture part, the results show that 15%WTR + 4%APAO modified mixture has better high temperature and fatigue performance after aging, among the rubber-based asphalt mixtures. The low-temperature performance of WTR/APAO asphalt mixture was not compromised after aging. Compared with the SBS modified asphalt mixture, the high and low-temperature performance of 15%WTR + 4%APAO asphalt mixture after aging are better. Overall, 15%WTR+4% APAO asphalt mixture has better advantages to counteract the influence of oxidative aging.

This study aims to characterize the transverse profile shapes (TPSs) of rutting on asphalt pavement and to produce useful information to the highway administration in what concerns rutting. A novel framework was developed to implement an accurate description on rutting, which integrates four steps (data acquisition, TPS adjustment, TPS categorization and indicator analysis). Various indexes were analyzed and used to characterize these profiles. A new dimensionality reduction method was constructed based on correlation coefficient matrix (CCM) to avoid the repetition of indexes. These data from the Long-Term Pavement Performance (LTPP) program were collected and screened in the study. The categorization and time-dependent evolution of TPS were conducted based on the developed framework. The statistical analysis and dimensionality reduction of these indexes were carried out. Results show that the established framework allows to categorize and accurately describe the TPS of rutting. The TPSs are divided into five typical shapes and an irregular shape, and the type 5 and the irregular shape are not very valuable. There are different time-dependent evolutions for various types of TPS, which may be associated with trajectory of vehicles. The obtained critical value of these indexes should be attracted an attention from road administrations. The constructed dimensionality reduction method is capable of eliminating the redundancy of indexes, and thus optimizing the characterization effects. Different types of TPS correspond to different index systems. Extensive work on the application of information proposed in this study is still need in predicting pavement performance and conducting maintenance decision-making in further.

Fiber optic sensors are increasingly used in several fast-growing industries. Aerospace, energy storage, and the medical sector consider new implementations of optical fibers mainly for condition monitoring purposes. Applications using optical fibers entail measurements of distributed strains and temperatures. However, the spectral shifts of transmitted and reflected light are simultaneously sensitive to both of these influences. This coupled sensitivity can introduce large errors for signal interpretation. An accurate calculation model for signal decoupling is necessary to distinguish pure mechanical strains from pure thermal loading. Approaches where the spectral shift is assumed to vary linearly with temperature give large errors when the temperature variation is high. This investigation derives and validates a new temperature formula that is used for high precision strain and temperature discrimination. The non-linear temperature formula is deduced from physics-based models and is validated with Rayleigh backscattering based OBR measurements. Our calculation approach demonstrates improved accuracy over an extended temperature range. The relationship between strain and temperature effects in the coupled mechanical and thermal loading environment is further studied in detail.

Aiming at evaluating the stability of a rock mass near a fault, a microseismic (MS) monitoring system was established in Hongtoushan copper mine. The distribution of displacement and log(EI), the relationship between MS activity and the exploitation process, and the stability of the rock mass controlled by a fault were studied. The results obtained from microseismic data showed that MS events were mainly concentrated at the footwall of the fault. When the distance to the fault exceeded 20 m, the rock mass reached a relatively stable state. MS activity is closely related to the mining process. Under the strong disturbance from blasting, the initiation and propagation of cracks is much faster. MS activity belongs in the category of aftershocks after large scale excavation. The displacement and log(EI) obtained from MS events can reflect the difference in physical and mechanical behavior of different areas within the rock mass, which is useful in judging the integrity and degradation of the rock mass. Keywords: Deep mining, Fault, Microseism (MS), Stability

The present study evaluated the long-term effectiveness of preventive maintenance treatments (PMTs) on pavement performance using the data collected in the Specific Pavement Studies-3 (SPS-3) of the Long-Term Pavement Performance (LTPP) program. The PMTs included thin overlay, slurry seal, crack seal and chip seal. Pavement performances included roughness, rutting, transverse cracking, longitudinal cracking and alligator cracking. A new framework was established in this study to evaluate pre-treatment pavement condition. Weighted distress was adopted to describe average long-term performance and a new indicator was proposed to characterize average long-term effectiveness increment. Scatterplot analysis, cumulative frequency distribution, average long-term effectiveness increment and pair-samples t-test were conducted to investigate the long-term effectiveness. Results indicate that the results from the four analysis methods are similar, so the proposed new indicator is capable of evaluating the long-term effectiveness of PMTs. Meanwhile, thin overlay and crack seal are the best and worst PMTs on each performance, respectively. In addition, there may be a critical original pavement condition in terms of the long-term effectiveness of PMTs on each performance respectively. The findings in this study may supply guidelines for the implementation of preventive maintenance decision-making.

Material extrusion (MEX) is a well established production method in additive manufacturing. However, internal residual strains are accumulated during the layer-by-layer fabrication process. They bring about shape distortions and a degradation of mechanical properties. In this paper, an in-situ distributed measurement of residual strains in MEX fabricated thermoplastic specimens is achieved for the first time. This innovative measuring system consists of an Optical Backscatter Reflectometry (OBR) interrogation unit connected to a distributed fiber optic strain sensor which is embedded during the MEX process. The characteristic residual strain distribution inside 3D printed components is revealed and numerically validated. The main mechanisms of residual strain creation and the sensing principles of in-situ OBR are described. A minimum measuring range of 4 mm and a spatial resolution of 0.15 mm were experimentally demonstrated. The potential of in-situ OBR technology for detecting invisible manufacturing defects was shown by a trial experiment. © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/BY/4.0/).T

The influence of cryogenic environment on mechanical properties of a unidirectional carbon fiber reinforced bismaleimide composite (T700/6421BMI composite) has been investigated in this study. Cryogenic treatment was performed by steeping the T700/6421BMI composite specimens in liquid nitrogen for 0,24,240,480,1200, 1920 and 2400 hours, respectively. After liquid nitrogen steeping treatment, the transverse tension test, three-point bending test, short beam shear test and impact test were carried out to evaluate the effect of steeping time on mechanical properties of the T700/6421BMI composite. The fracture surface morphology of typical specimens was examined by SEM while the chemical variation and interface damage of the composite were characterized by FTIR and DMA. The results indicate that mechanical properties of the T700/6421BMI composite are affected by liquid nitrogen steeping. The bending strength displays a tendency of decreasing firstly then rising with increase in steeping time, and the shear strength exhibits on the contrary. The total impact energy and crack propagation energy of the T700/6421BMI composite increases rapidly in the initial stage and increases slightly as increases LN2 steeping time. It is suggested that the mechanical properties of the T700/6421BMI composite after liquid nitrogen steeping might be dominated by interface state related to steeping time. With the increase in steeping time, the stress concentration in the surface of matrix and fiber induced by coefficient of thermal expansion (CTE) difference increases and might cause interface debonding.

In digital integrated circuit designing, energy dissipation has become a crucial factor which engineers would consider before they begin the design. However, irreversible computing is one of the most significant factors of energy dissipation. Therefore, designing digital circuits by reversible logic way is an efficient way to decline the energy dissipation of the circuit. In this paper, we proposed a 16-bit carry skip adder which is an optimization of traditional ripple carry adder designed by reversible logic.