Study of Real-road Nitrogen Oxide Emissions of Non-road Vehicles

The exhaust gas pollutants of the non-road vehicles are harmful to the environment. Many non-road vehicles meet the requirements of the regulations in the laboratory. However, the real-road emissions of such vehicles are sometimes higher. Measuring the real-road emissions of non-road vehicles is very important. The real-road emissions are measured by on-Board Diagnostics (OBD), but there are some problems in the data stability of OBD. The NOx emissions of a bulldozer (a type of China IV non-road vehicle) based on both portable emission measurement system (PEMS) and OBD are studied in this article. Experiments contained three working processes: idle, driving, and operating. The nitrogen oxide (NOx) emissions during operating were highest. The NOx emission characteristics of the bulldozer from PEMS and OBD have the similar variation trends. But there are still some differences, including the NOx emission value and response time. The measurement principles and different sampling points between PEMS and OBD are the main factors. An effective data processing method is introduced to reduce the differences of between the data from PEMS and OBD. Briefly, the NOx emissions of the OBD and PEMS were highly consistent. The OBD is reliable and can be widely used in non-road vehicles.

Exploring New Strategies for Ultrahigh Strength Steel via Tailoring the Precipitates

Ultrahigh-strength (UHS) steels have shown great potential in the field of high-end equipment manufacturing in demand of lightweight engineering and performance upgrade. A significant research effort has been directed toward the development of advanced UHS steels with excellent combination of strength and toughness. In the course of development, tailoring precipitates by means of composition design and process optimization is absolutely a critical module. In this mini review, typical UHS steels strengthened by carbides and intermetallics are systematically summarized and discussed. With the increase of strength, the toughness losses of UHS steels strengthened by carbides and intermetallics have been compared in detail. In particular, the in-depth mechanisms leading to various strength/toughness variation trends have been discussed, extracting the bottleneck in developing new-generation UHS steels containing merely one type of precipitate. Meanwhile, prospects on designing advanced UHS steels strengthened by coexisting dispersive precipitates have been proposed to achieve better performance.

A Composite Matching Layer with Anti-Reflection Characteristics for Broadband Acoustic Scattering Reduction

A composite matching layer composed of periodically arranged scatters with anti-reflection (AR) characteristics is proposed for broadband scattering reduction. The anti-reflection structure is composed of periodically arranged metal foam scatters, and it is the first attempt to be applied in the field of suppressing acoustic reflection. A complete theoretical model is developed to reveal the mechanism of scattering reduction and acoustic absorption based on effective medium theory and the transfer matrix method. The correctness and effectiveness of the theoretical model are verified by the finite element method (FEM), showing acoustic reflectance of less than 13.5% at broadband frequencies. The variation trends of reflectance are deeply investigated. The superior acoustic scattering reduction performance suggests that the matching layer possesses potential for acoustic imaging equipment and acoustic stealth.

The regional features of precipitation variation trends over Sichuan in China by the ESMD method

Based on a precipitation time series from 49 meteorological stations in Sichuan Province during the period from 1961 to 2011, the multi-scale characteristics of precipitation variability are analyzed using the extreme-point symmetric mode decomposition method (ESMD). Regional differences in variation trends and change-points were also preliminarily discussed. The results indicated that in the last 50+ years, the overall precipitation in Sichuan Province has exhibited a significant non-linear downward trend, and its changes have clearly exhibited an inter-annual scale (quasi-3 and quasi-8-year) and interdecadal scale (quasi-13-year). The variance contribution rates of each component demonstrated that the inter-annual change had a strong influence on the overall precipitation change in Sichuan Province, and the reconstructed inter-annual variation trend could describe the fluctuation state of the original precipitation during the study period. The reconstructed interdecadal variability revealed that the climate mode in Sichuan Province had divided into three distinct variation periods with 1973 and 1998 as the boundaries. Furthermore, there were regional differences in the non-linear changes and change-points of precipitation. In addition, in order to study the relations between the changing more or less of rising or decrease and meteorological station’s geographical position (latitude, longitude and elevation) i.e., the Cokriging interpolation technique is applied directly to precipitation variation trend components through ESMD decomposition. At the same time, the results also suggested that the ESMD method can effectively reveal variations in long-term precipitation sequences at different time scales and can be used for the complex diagnosis of non-linear and non-stationary signal changes.

The Petrology and Petrochemistry of Andesite and Dacite Volcanoes in Eastern Bay of Plenty, New Zealand

<p>The volcanic rocks of Edgecumbe, Whale Island, White Island and Manawahe are andesites and dacites, which are collectively termed the Bay of Plenty volcanics. Edgecumbe is a comparatively young volcano, being active between 1700 and 8000 years B.P.; Whale Island has probably been inactive for at least the last 36,000 years; White Island has probably been active for much of the late Pleistocene, and is still in a stage of solfataric activity with intermittent tephra eruptions; and Manawahe is probably of the order of 750,000 year old (K-Ar date by J.J. Stipp). The geology of Edgecumbe, Whale Island and White Island is discussed, and the petrography and mineralogy of the Bay of plenty volcanics is discussed and compared. The rocks of Edgecumbe and Whale Island are extremely similar petrographically, but the rocks of White Island and Manawahe are sufficiently different that they can be distinguished both from one another and from Edgecumbe and Whale Island rocks. Most of the Bay of Plenty volcanics are plagioclase andesites or plagioclase dacites. New total rock analyses for 28 elements in 44 samples of the Bay of Plenty volcanics are presented, together with analyses of 4 samples from elsewhere in the Taupo Volcanic Zone. Three samples were analysed for an additional 17 elements. The Bay of Plenty volcanics are calc-alkaline and are predominantly dacites (greater than or equal to 63% SiO2) by Taylor et al.'s (1969) definition, but there is chemical continuity from samples with about 61% SiO2 to samples with about 66% SiO2. Major and trace element variation trends cannot be explained entirely by a crystal fractionation hypothesis, and assimilation of upper crustal material of rhyolitic composition best explains the variation trends for Edgecumbe and Whale Island. The variation trends and certain element abundances in White Island rocks suggest the assimilation of marine sediments, and introduction of seawater into the magma. Taken as a whole, the Bay of Plenty volcanics fit the chemical trends which have been established for the Taupo Zone by earlier workers (e.g. Steiner, 1958; Clark, 1960). The apparent geochemical 'gap' or discontinuity between about 68% and 71.5% SiO2 noted by Steiner (1958) is further substantiated by the new geochemical data presented here. It is considered likely that basalt, andesite and rhyolite are all primary magmas in the Taupo Volcanic Zone. Their possible origins, and the origins of Taupo Zone dacites are discussed.</p>

The Petrology and Petrochemistry of Andesite and Dacite Volcanoes in Eastern Bay of Plenty, New Zealand

<p>The volcanic rocks of Edgecumbe, Whale Island, White Island and Manawahe are andesites and dacites, which are collectively termed the Bay of Plenty volcanics. Edgecumbe is a comparatively young volcano, being active between 1700 and 8000 years B.P.; Whale Island has probably been inactive for at least the last 36,000 years; White Island has probably been active for much of the late Pleistocene, and is still in a stage of solfataric activity with intermittent tephra eruptions; and Manawahe is probably of the order of 750,000 year old (K-Ar date by J.J. Stipp). The geology of Edgecumbe, Whale Island and White Island is discussed, and the petrography and mineralogy of the Bay of plenty volcanics is discussed and compared. The rocks of Edgecumbe and Whale Island are extremely similar petrographically, but the rocks of White Island and Manawahe are sufficiently different that they can be distinguished both from one another and from Edgecumbe and Whale Island rocks. Most of the Bay of Plenty volcanics are plagioclase andesites or plagioclase dacites. New total rock analyses for 28 elements in 44 samples of the Bay of Plenty volcanics are presented, together with analyses of 4 samples from elsewhere in the Taupo Volcanic Zone. Three samples were analysed for an additional 17 elements. The Bay of Plenty volcanics are calc-alkaline and are predominantly dacites (greater than or equal to 63% SiO2) by Taylor et al.'s (1969) definition, but there is chemical continuity from samples with about 61% SiO2 to samples with about 66% SiO2. Major and trace element variation trends cannot be explained entirely by a crystal fractionation hypothesis, and assimilation of upper crustal material of rhyolitic composition best explains the variation trends for Edgecumbe and Whale Island. The variation trends and certain element abundances in White Island rocks suggest the assimilation of marine sediments, and introduction of seawater into the magma. Taken as a whole, the Bay of Plenty volcanics fit the chemical trends which have been established for the Taupo Zone by earlier workers (e.g. Steiner, 1958; Clark, 1960). The apparent geochemical 'gap' or discontinuity between about 68% and 71.5% SiO2 noted by Steiner (1958) is further substantiated by the new geochemical data presented here. It is considered likely that basalt, andesite and rhyolite are all primary magmas in the Taupo Volcanic Zone. Their possible origins, and the origins of Taupo Zone dacites are discussed.</p>

Transcriptomic Analysis of Laying Hens Revealed the Role of Aging-Related Genes during Forced Molting

Molting in birds provides us with an ideal genetic model for understanding aging and rejuvenation since birds present younger characteristics for reproduction and appearance after molting. Forced molting (FM) by fasting in chickens causes aging of their reproductive system and then promotes cell redevelopment by providing water and feed again. To reveal the genetic mechanism of rejuvenation, we detected blood hormone indexes and gene expression levels in the hypothalamus and ovary of hens from five different periods during FM. Three hormones were identified as participating in FM. Furthermore, the variation trends of gene expression levels in the hypothalamus and ovary at five different stages were found to be basically similar using transcriptome analysis. Among them, 45 genes were found to regulate cell aging during fasting stress and 12 genes were found to promote cell development during the recovery period in the hypothalamus. In addition, five hub genes (INO80D, HELZ, AGO4, ROCK2, and RFX7) were identified by WGCNA. FM can restart the reproductive function of aged hens by regulating expression levels of genes associated with aging and development. Our study not only enriches the theoretical basis of FM but also provides insights for the study of antiaging in humans and the conception mechanism in elderly women.

Molecular dynamics investigation on tilt grain boundary energies of beta-titanium and tungsten at high temperature

The grain boundary energies (GBEs) of symmetric tilt grain boundaries (STGBs) and asymmetric tilt grain boundaries (ATGBs) for W at 0 and 2400 K and β-Ti at 1300 K were calculated by means of Molecular static method and Molecular dynamic simulations to investigate the effects of high temperature and grain boundary (GB) planes on the GBE. Generally, the variation trends of GBEs functioned with tilt angle are similar in the three cases when the tilt axis is specified. It is of course that these similarities result from their similar GB microstructures in most cases. However, the variation trends of β-Ti at 1300 K are somewhat different from that of W at 2400 K for STGBs with <100> and <110> tilt axes. This difference mainly stems from the following two reasons: firstly, the GB microstructures of W at 2400 K and β-Ti at 1300 K are different for some STGBs; secondly, the atoms at STGB of β-Ti at 1300 K tend to evolve into the local ω- or α-like structures distributed at STGBs, which make the corresponding STGBs more stable, thereby decreasing the GBEs. Furthermore, a geometric parameter θ, an angle between misorientation axis and GB plane, was defined to explore the effects of GB planes on GBEs. It was found that the relationship between GBEs and sin(θ) can be described by some simple functions of sin(θ) for the GBs with definite lattice misorientation, which can well explain and predict the preferred GB planes for the GBs with specific lattice misorientation. Our calculations not only extend the investigation of GBs to higher temperature, but also deepen the understanding on the temperature contribution to the microstructure evolution at GBs and on the relationship between GBE and possible geometric parameters.

Numerical simulation on the leakage and diffusion of the natural gas of the underground pipeline in the soil

For the transportation pipeline with the diameter 1.219 m and the internal pressure 3-12 MPa, the leakage and diffusion of the natural gas of the pipeline in the soil was studied by numerical simulation. First, the finite model containing both pipeline and soil was established, and the porous media was used to simulate the real soil environment. And, the leakage amount of the natural gas was calculated at the cases with different porosities, the pressures inside the pipeline and the diameters of leakage port. Based on the classical theoretical leakage model of small hole in the air and simulation results analysis, the formula of the leakage amount was modified by the soil coefficient α to be suitable for soil environment. Then, the variation trends of the diffusion concentration of methane along different directions in the soil were analyzed by simulation, the influences of internal pressure of pipeline, the diameter of leakage and the porosity of soil were also discussed. Besides, the relationship of the safety distance with time was obtained.

Variation Trends of Fractal Dimension in Epileptic EEG Signals

Epileptic diseases take EEG as an important basis for clinical judgment, and fractal algorithms were often used to analyze electroencephalography (EEG) signals. However, the variation trends of fractal dimension (D) were opposite in the literature, i.e., both D decreasing and increasing were reported in previous studies during seizure status relative to the normal status, undermining the feasibility of fractal algorithms for EEG analysis to detect epileptic seizures. In this study, two algorithms with high accuracy in the D calculation, Higuchi and roughness scaling extraction (RSE), were used to study D variation of EEG signals with seizures. It was found that the denoising operation had an important influence on D variation trend. Moreover, the D variation obtained by RSE algorithm was larger than that by Higuchi algorithm, because the non-fractal nature of EEG signals during normal status could be detected and quantified by RSE algorithm. The above findings in this study could be promising to make more understandings of the nonlinear nature and scaling behaviors of EEG signals.