Measuring multi-scale urban forest carbon flux dynamics using an integrated eddy covariance technique

The multi-scale carbon-carbon dioxide (C-CO2) dynamics of subtropical urban forests and other green and grey infrastructure types were explored in an urbanized campus near Shanghai, China. We integrated eddy covariance (EC) C-CO2 flux measurements and the Agroscope Reckenholz-Tänikon footprint tool to analyze C-CO2 dynamics at the landscape-scale as well as in local-scale urban forest patches during one year. The approach measured the C-CO2 flux from different contributing areas depending on wind directions and atmospheric stability. Although the study landscape was a net carbon source (2.98 Mg C ha-1 yr-1), we found the mean CO2 flux in urban forest patches was -1.32 ?mol m-2s-1, indicating that these patches function as a carbon sink with an annual carbon balance of -5.00 Mg C ha-1. These results indicate that urban forest patches and vegetation (i.e., green infrastructure) composition can be designed to maximize the sequestration of CO2. This novel integrated modeling approach can be used to facilitate the study of the multi-scale effects of urban forests and green infrastructure on CO2 and to establish low-carbon emitting planning and planting designs in the subtropics. © 2019 by the authors

Decreased adiponectin and increased inflammation expression in epicardial adipose tissue in coronary artery disease

<p>Abstract</p> <p>Background</p> <p>Disorders of endocrine substances in epicardial adipose tissue are known causes of coronary artery disease (CAD). Adiponectin is associated with cardiovascular disease. However, expression of adiponectin in epicardial adipose tissue and its function in CAD pathogenesis is unclear. This study investigates adiponectin expression in epicardial adipose tissue in CAD patients.</p> <p>Methods</p> <p>Vessels or adipose tissue samples collected from CAD patients and non-CAD controls were examined after immunochemical staining. Adiponectin, cytokines of interleukin-6 (IL-6) and necrosis factor-α (TNF-α) and toll-like receptor 4 (TLR4) expression level in adipose tissue were measured using real-time quantitative RT-PCR. Adiponectin concentrations in peripheral and coronary sinus vein plasma were measured with enzyme-linked immunosorbent assay. Peripheral vein plasma biochemistries were performed with routine laboratory techniques. Monocytes were collected from blood using lymphocyte separation medium. Expression level of cytokines and transcription factor NF-κB were measured to learn the effect of adiponectin on stearic acid-stimulated monocytes. Percentage of TLR4 positive monocytes was analyzed using flow cytometry.</p> <p>Results</p> <p>Histological examination revealed increased macrophage infiltration into epicardial adipose tissue of CAD patients. Decreased adiponectin displayed by real-time quantitative RT-PCR was associated with enhanced cytokines of IL-6 and TNF-α or TLR4 expression level in epicardial adipose tissue, suggesting decreased circulating adiponectin may be useful as a more sensitive predictor for coronary atherosclerosis than routine laboratory examinations. Adiponectin suppressed secretion of IL-6 and TNF-α in stimulated monocytes and TLR4 was expressed on cell surfaces.</p> <p>Conclusions</p> <p>Endocrine disorders in epicardial adipose tissue are strongly linked to CAD, and adiponectin has a protective effect by inhibiting macrophage-mediated inflammation.</p

Psychology State Acquiring Device Based on Sitting Postures for Implicit Interaction

Context-aware is very important for implicit interaction. User's psychology state as a kind of user context can be used in the interaction to improve quality and to make the service more individual. In this paper, a psychology state acquiring device based on sitting postures for implicit interaction is developed. The device consists of two parts: pressure sensor matrix and micro control unit. The former is made up of 40 pairs of pressure sensor node to sense pressure distribution on it, and the latter has a power supply module, first/second level CD4051 parts, operational amplifier LM324, AD0804, and STC89C52RC mainly to realize sampling control and analysis. With this device, several experiments are carried on. It can be seen that the effect is good enough in single set testing, area (palm/sitting) testing and the actual environment testing. So it can be used in implicit human computer interaction researches and applied in another area

Effect of growth rate on characteristic lengths of microstructure in directionally solidified

The microstructure of TiAl based alloys is sensitive to growth rates. In this paper, Bridgman directional solidification of Ti-46Al-2Cr-2Nb-0.2B (at.%) alloy was carried out at a constant temperature gradient (G) to investigate the effects of various growth rates (v) on characteristic lengths (primary dendritic arm spacing, secondary dendritic arm spacing and lamellar spacing) of the microstructure. Results show that under the experimental conditions of G = 18 K·m-1 and v = 15 μm·s-1 to 70 μm·s-1, the primary phase of directionally solidified Ti-46Al-2Cr-2Nb-0.2B alloy is α phase, the values of primary dendritic arm spacing (λ1), secondary dendritic arm spacing (λ2) and lamellar spacing (λ1a) decrease with the increase in growth rate. The results were compared with theoretical models and similar experimental results of TiAl based alloys. The Bouchard-Kirkaldy model agrees well with the relationship between primary dendritic arm spacing and growth rate obtained in the experiment; the relationship between them can be expressed by λ1 = 758.6v-0.39. The relationship between the secondary dendritic arm spacing and the growth rate can be expressed by λ2 = 113.9v-0.45, while the relationship between the lamellar spacing and growth rate can be expressed by λ1a = 22.88v-0.94

Field Measurement and Analysis on the Mechanical Response of Asphalt Pavement Using Large-Particle-Size Crushed Stone Base Treated with Fly Ash and Slag Powder

The mechanical response of asphalt pavement under vehicular loading is an essential reference for crack-resistant pavement design. However, limited research focuses on the mechanical response measurement of asphalt pavement using a large-particle-size crushed stone base treated with fly ash and slag powder. Therefore, two types of asphalt pavements were constructed. The first type of asphalt pavement uses a large-particle-size crushed stone base treated with fly ash and slag powder, where the slag powder uses granulated blast furnace slag powder. The second type uses a conventional cement-stabilized crushed stone base and serves as a reference structure. Firstly, the strain gauges and temperature sensors were installed during the construction of asphalt pavements. Secondly, the mechanical response of the pavement was tested at different speeds and service time conditions. Then, sensitivity analysis and three-factor analysis of variance (ANOVA) were carried out. Finally, the prediction equations were developed. The results show that the longitudinal strain pulse of the asphalt layer exhibited a “compression–tension–compression” characteristic. For the transverse strain pulse of the asphalt layer, the base layer’s transverse and longitudinal strain pulses were only shown as “tensile” characteristics. The vehicular speed significantly affected the strain values for the base and asphalt layers, showing a decreasing trend with increasing speed. For the asphalt layer, the strain values showed an increasing trend with increasing temperature; for the base layer, the strain values showed a decreasing trend with increasing service time. The type of base layer had a significant effect on the strain value. Compared with the conventional base layer, the large-particle-size crushed stone base treated with fly ash and slag powder had lower strain at the base layer and a lower position of the asphalt layer, which could better prevent bottom-up fatigue cracking. Finally, the strain prediction model of the pavement under the speed and temperature (service time) was fitted to obtain a model that can predict the mechanical response of the pavement under different operating conditions. The findings of this research can provide a reference for the design of asphalt pavement using a large-particle-size crushed stone base treated with fly ash and slag powder

Microstructure and properties of stationary shoulder friction stir welded joints for aluminum alloy thick-plate

The stationary shoulder friction stir welding (SSFSW) processes for 2A14-T4 aluminum alloy with the thickness of 8.5 mm were performed by using the self-developed tools, and the influences of welding process parameters on the microstructure and mechanical properties of SSFSW welded joints were investigated. The results show that the SSFSW joints with smooth weld surface and defect-free for aluminum alloy thick-plate can only be obtained under the process parameter condition of lower rotational speed (rotational speed ω=400-600 r/min and welding speed v=60-120 mm/min).The weld zone of SSFSW joints mainly consists of nugget zone (NZ), and the widths of thermo-mechanically affected zone (TMAZ) and the heat affected zone (HAZ) around the NZ are obviously reduced; the NZ is similar with the shape of tool pin and it is composed of two kinds of fine equiaxed grains with different sizes, the grains on the advancing side are more finer than that of retreating side. The profiles of microhardness across the weld section present the "W" shape, the hardness values of NZ reach the 80%-90% of the base metal of hardness value, the softened region is produced between interfaces of TMAZ and HAZ, and its hardness is the lowest with the 72% of the base metal of hardness value. The tensile strengths of SSFSW joints reach the 88% of base metal under the welding parameters of ω=500 r/min, v=140 mm/min, and the fractured sites are always located at the softened zones between TMAZ and HAZ on the retreating side, exhibiting the toughness fracture features

Measuring multi-scale urban forest carbon flux dynamics using an integrated eddy covariance technique

The multi-scale carbon-carbon dioxide (C-CO2) dynamics of subtropical urban forests and other green and grey infrastructure types were explored in an urbanized campus near Shanghai, China. We integrated eddy covariance (EC) C-CO2 flux measurements and the Agroscope Reckenholz-Tänikon footprint tool to analyze C-CO2 dynamics at the landscape-scale as well as in local-scale urban forest patches during one year. The approach measured the C-CO2 flux from different contributing areas depending on wind directions and atmospheric stability. Although the study landscape was a net carbon source (2.98 Mg C ha-1 yr-1), we found the mean CO2 flux in urban forest patches was -1.32 ?mol m-2s-1, indicating that these patches function as a carbon sink with an annual carbon balance of -5.00 Mg C ha-1. These results indicate that urban forest patches and vegetation (i.e., green infrastructure) composition can be designed to maximize the sequestration of CO2. This novel integrated modeling approach can be used to facilitate the study of the multi-scale effects of urban forests and green infrastructure on CO2 and to establish low-carbon emitting planning and planting designs in the subtropics. © 2019 by the authors

Mobile Edge Computing in Space-Air-Ground Integrated Networks: Architectures, Key Technologies and Challenges

Space-air-ground integrated networks (SAGIN) provide seamless global coverage and cross-domain interconnection for the ubiquitous users in heterogeneous networks, which greatly promote the rapid development of intelligent mobile devices and applications. However, for mobile devices with limited computation capability and energy budgets, it is still a serious challenge to meet the stringent delay and energy requirements of computation-intensive ubiquitous mobile applications. Therefore, in view of the significant success in ground mobile networks, the introduction of mobile edge computing (MEC) in SAGIN has become a promising technology to solve the challenge. By deploying computing, cache, and communication resources in the edge of mobile networks, SAGIN MEC provides both low latency, high bandwidth, and wide coverage, substantially improving the quality of services for mobile applications. There are still many unprecedented challenges, due to its high dynamic, heterogeneous and complex time-varying topology. Therefore, efficient MEC deployment, resource management, and scheduling optimization in SAGIN are of great significance. However, most existing surveys only focus on either the network architecture and system model, or the analysis of specific technologies of computation offloading, without a complete description of the key MEC technologies for SAGIN. Motivated by this, this paper first presents a SAGIN network system architecture and service framework, followed by the descriptions of its characteristics and advantages. Then, the MEC deployment, network resources, edge intelligence, optimization objectives and key algorithms in SAGIN are discussed in detail. Finally, potential problems and challenges of MEC in SAGIN are discussed for future work