Information Analysis of Catchment Hydrologic Patterns across Temporal Scales

Catchment hydrologic cycle takes on different patterns across temporal scales. The interim between event-scale hydrologic process and mean annual water-energy correlation pattern requires further examination to justify self-consistent understanding. In this paper, the temporal scale transition revealed by observation and simulation was evaluated in an information theoretical framework named Aleatory Epistemic Uncertainty Estimation. The Aleatory Uncertainty refers to posterior uncertainty of runoff given the input variables’ observations. The Epistemic Uncertainty refers to the posterior uncertainty increase due to the imperfect observation decoding in models. Daily hydrometeorological observations in 24 catchments were aggregated from 10 days to 1 year before implementing the information analysis. Estimations of information contents and flows of hydrologic terms across temporal scales were related with the catchments’ seasonality type. It also showed that information distilled by the monthly and annual water balance models applied here did not correspond to that provided by observations around temporal scale from two months to half a year. This calls for a better understanding of seasonal hydrologic mechanism

A novel low-temperature fabrication approach of composite phase change materials for high temperature thermal energy storage

Phase change materials (PCMs) are generally integrated into matrix materials to form shape-stabilized composite heat storage materials (HSMs) used for high temperature thermal energy storage applications. The conventional fabrication of composite HSMs is prevalently implemented at quite high temperatures, which is energy-intensive and narrows down the range of applicable PCMs because of thermal decomposition. Therefore, this paper establishes a novel fabrication approach to accomplish highly dense matrix to encapsulate PCMs at extremely low temperatures, based on the recently developed cold sintering process. The feasibility of the proposed approach was demonstrated by a case study of NaNO3/Ca(OH)2 composite HSMs. It was observed that the Ca(OH)2 matrix formed dense microstructure with obvious sintered boundaries and successfully encapsulated NaNO3 as PCM. The HSMs maintained stable macroscopic shape after hundreds of thermal cycles, and exhibited an energy storage efficiency of 59.48%, little leakage of PCM, and good thermal stability. Mechanical tests indicated that the HSMs possessed excellent mechanical properties when the sintering pressure is over 220 MPa. The discharging time of stored heat was presented through infrared thermography, and the heat storage capacity measured for the composite HSMs was over four times as high as those of typical solid storage materials of sensible heat, which demonstrated their excellent heat storage performances. The HSMs can be used in the form of packed bed or parallel channel with multi-layered heat storage, which is beneficial for efficiently utilizing solar heat and improving the performance of current energy storage system. This study therefore provides a novel route for energy-saving and low-carbon fabrication of shape-stabilized composite HSMs

TRH Analog, Taltirelin Protects Dopaminergic Neurons From Neurotoxicity of MPTP and Rotenone

Dopaminergic neurons loss is one of the main pathological characters of Parkinson’s disease (PD), while no suitable neuroprotective agents have been in clinical use. Thyrotropin-releasing hormone (TRH) and its analogs protect neurons from ischemia and various cytotoxins, but whether the effect also applies in PD models remain unclear. Here, we showed that Taltirelin, a long-acting TRH analog, exhibited the neuroprotective effect in both cellular and animal models of PD. The in vitro study demonstrated that Taltirelin (5 μM) reduced the generation of reactive oxygen species (ROS) induced by MPP+ or rotenone, alleviated apoptosis and rescued the viability of SH-SY5Y cells and rat primary midbrain neurons. Interestingly, SH-SY5Y cells treated with Taltirelin also displayed lower level of p-tau (S396) and asparagine endopeptidase (AEP) cleavage products, tau N368 and α-synuclein N103 fragments, accompanied by a lower intracellular monoamine oxidase-B (MAO-B) activity. In the subacute MPTP-induced and chronic rotenone-induced PD mice models, we found Taltirelin (1 mg/kg) significantly improved the locomotor function and preserved dopaminergic neurons in the substantia nigra (SN). In accordance with the in vitro study, Taltirelin down-regulated the levels of p-tau (S396), p-α-synuclein (S129) tau N368 and α-synuclein N103 fragments in SN and striatum. Together, this study demonstrates that Taltirelin may exert neuroprotective effect via inhibiting MAO-B and reducing the oxidative stress and apoptosis, preventing AEP activation and its subsequent pathological cleavage of tau and α-synuclein, thus provides evidence for Taltirelin in protective treatment of PD

TRH Analog, Taltirelin Improves Motor Function of Hemi-PD Rats Without Inducing Dyskinesia via Sustained Dopamine Stimulating Effect

Thyrotropin-releasing hormone (TRH) and its analogs are able to stimulate the release of the endogenic dopamine (DA) in the central nervous system. However, this effect has not been tested in the Parkinson’s disease (PD), which is characterized by the DA deficiency due to the dopaminergic neurons loss in the substantia nigra. Here, we investigated the therapeutic effect of Taltirelin, a long-acting TRH analog on 6-hydroxydopamine-lesioned hemi-Parkinsonian rat model. 1–10 mg/kg Taltirelin i.p. administration significantly improved the locomotor function and halted the electrophysiological abnormities of PD animals without inducing dyskinesia even with high-dose for 7 days treatment. Microdialysis showed that Taltirelin gently and persistently promoted DA release in the cortex and striatum, while L-DOPA induced a sharp rise of DA especially in the cortex. The DA-releasing effect of Taltirelin was alleviated by reserpine, vanoxerine (GBR12909) or AMPT, indicating a mechanism involving vesicular monoamine transporter-2 (VMAT-2), dopamine transporter (DAT) and tyrosine hydroxylase (TH). The in vivo and in vitro experiments further supported that Taltirelin affected the regulation of TH expression in striatal neurons, which was mediated by p-ERK1/2. Together, this study demonstrated that Taltirelin improved motor function of hemi-PD rats without inducing dyskinesia, thus supporting a further exploration of Taltirelin for PD treatment

Evapotranspiration estimation considering anthropogenic heat based on remote sensing in urban area

Urbanization influences hydrologic cycle significantly on local, regional even global scale. With urbanization the water resources demand for dense population sharpened, thus it is a great challenge to ensure water supply for some metropolises such as Beijing. Urban area is traditionally considered as the area with lower evapotranspiration (ET) on account of the impervious surface and the lower wind speed. For most remote sensing models, the ET, defined as latent heat in energy budget, is estimated as the difference between net radiation and sensible heat. The sensible heat is generally higher in urban area due to the high surface temperature caused by heat island, therefore the latent heat (i.e. the ET) in urban area is lower than that in other region. We estimated water consumption from 2003 to 2012 in Beijing based on water balance method and found that the annual mean ET in urban area was about 654 mm. However, using Surface Energy Balance System (SEBS) model, the annual mean ET in urban area was only 348 mm. We attributed this inconsistence to the impact of anthropogenic heat and quantified this impact on the basis of the night-light maps. Therefore, a new model SEBS-Urban, coupling SEBS model and anthropogenic heat was developed to estimate the ET in urban area. The ET in urban area of Beijing estimated by SEBS-Urban showed a good agreement with the ET from water balance method. The findings from this study highlighted that anthropogenic heat should be included in the surface energy budget for a highly urbanized area

Remotely Sensed Soil Moisture Assimilation in the Distributed Hydrological Model Based on the Error Subspace Transform Kalman Filter

The data assimilation of remotely sensed soil moisture observations provides a feasible path of improving river flow simulation. In this work, we studied the performance of the error subspace transform Kalman filter (ESTKF) assimilation algorithm on the assimilation of remotely sensed soil moisture from SMAP, including the improvement of soil moisture and river flow in the hydrological model. Additionally, we discussed the advantages and added value of ESTKF compared to the ensemble Kalman filter (EnKF) in a hydrological model. To achieve this objective, we solved the spatial resolution gap between the remotely sensed soil moisture and the simulated soil moisture of the hydrological model. The remotely sensed soil moisture from SMAP was assimilated into the first layer soil moisture in the distributed hydrological model. The spatial resolution of the hydrological model was 600 m, while the spatial resolution of the SMAP remotely sensed soil moisture was 9 km. There is a considerable gap between the two spatial resolutions. By employing observation operators and observation localization based on geolocation, the distributed hydrological model assimilated multiple remotely sensed soil moisture values for each grid, thereby ensuring the consistent updates of soil moisture in the model. The results show the following: (1) In terms of improving soil moisture, we found that both ESTKF and EnKF were effective, and the ubRMSE of ESTKF was lower than that of EnKF. (2) ESTKF improved most cases where open-loop high river flow simulations were too low, but EnKF did not improve this situation. (3) In ESTKF, the relative error of flood volume was reduced on average to 2.52%, but the relative error of flood peak did not improve. The results provide evidence of the value of ESTKF in the hydrological model

Response of vegetation dynamics to climatic variables across a precipitation gradient in the Northeast China Transect

<p>This study investigated the influence of climatic variables on the spatio-temporal variation of vegetation growth using normalized difference vegetation index (NDVI) data and climate data from 2000 to 2013 in the Northeast China Transect. Partial correlation and linear regression methods were applied to quantify the response of the growing season NDVI to climatic variables. Gradient analysis was used to investigate how the response changes across the precipitation gradient over the transect. The results show that, at the spatial scale, NDVI increases with precipitation in grassland, and the spatial sensitivity is 0.001/mm. At the temporal scale, grassland NDVI is less correlated with precipitation in wet areas where precipitation exceeds a threshold of 250 mm. The temporal sensitivity of grassland NDVI to precipitation is 0.0003–0.0006/mm. Positive correlations between NDVI and temperature dominate in forest areas, and forest NDVI is sensitive to temperature by 0.06–0.12/°C.</p

Microstructure and Fatigue Damage of 316L Stainless Steel Manufactured by Selective Laser Melting (SLM)

In this paper, 316L stainless steel powder was processed and formed by selective laser melting (SLM). The microstructure of the sample was studied using an optical microscope, and the fatigue failure of the sample and the characteristics of crack initiation and propagation were analyzed, providing a research basis for the application of SLM-316L. Due to the influence of microstructure and SLM process defects, the fatigue cracks of SLM-316L mainly emerged due to defects such as lack of fusion and pores, while the cracks of rolled 316L initiated at the inclusions near the surface of the specimen. After fatigue microcrack initiation of the SLM-316L specimen, due to the existence of shear stress and tear stress, the crack tip was passivated and Z-shaped propagation was formed. The existence of internal defects in SLM-316L made the microcrack initiation random and diverse. At the same time, the existence of defects affected the crack propagation in the form of bending, bifurcation and bridge, which made the main crack propagation deviate from the maximum load direction