Geo-registration of Unprofessional and Weakly-related Image and Precision Evaluation

The 3D geo-spatial model built by unprofessional and weakly-related image is a significant source of geo-spatial information. The unprofessional and weakly-related image cannot be useful geo-spatial information until be geo-registered with accurate geo-spatial orientation and location. In this paper, we present an automatic geo-registration using the coordination acquired by real-time GPS module. We calculate 2D and 3D spatial transformation parameters based on the spatial similarity between the image location in the geo-spatial coordination system and in the 3D reconstruction coordination system. Because of the poor precision of GPS information and especially the unstability of elevation measurement, we use RANSAC algorithm to get rid of outliers. In the experiment, we compare the geo-registered image positions to their differential GPS coordinates. The errors of translation, rotation and scaling are evaluated quantitively and the causes of bad result are analyzed. The experiment demonstrates that this geo-registration method can get a precise result with enough images

Variation Characteristics of Stable Isotopes in Precipitation and Response to Regional Climate Conditions during Pre-monsoon, Monsoon and Post-monsoon Periods in the Tianshui Area

The stable isotopes in precipitation provide a new understanding for the mechanism study of water cycles in the Loess Plateau. However, there has never been an introduction for the Tianshui area, which is transitioning from semi-humid to semi-arid. We analyzed the time series changes of stable isotopes in precipitation at seven sampling points during pre-monsoon, monsoon and post-monsoon periods (April to October) in the Tianshui area. The results show that the temperature effect not only shows spatial differences but also seasonal changes and a weak precipitation effect is only found during the monsoon period. At the same time, the variation characteristics of precipitation isotopes before and after the monsoon clearly record the advancing and retreating time of the monsoon. We captured this important time node around 7 May and 21 September. Due to the influence of the regional microclimate formed by different natural conditions, the kinetic fractionation effect of isotopes in precipitation cause obvious differences in the slope and intercept of the meteoric water line in different natural regions, which shows that the stable isotopes in precipitation with high-resolution changes in a short period of time are of great significance to deeply explore the hydrological process of regional microclimates

Seasonal changes of soil erosion and its spatial distribution on a long gentle hillslope in the Chinese Mollisol region

Understanding seasonal soil erosion and deposition rates and their spatial distribution along sloping farmlands are necessary for erosion prediction technology and implementing effective soil conservation practices. To date seasonal change of soil erosion and soil redistribution on long gentle hillslopes are not fully quantified due to the variable erosive forces in different seasons. A multi-tracer method using rare earth elements (REE) was employed to discriminate seasonal changes of soil erosion and its spatial distribution on a sloping farmland driven by snowmelt runoff, wind force and rainfall-runoff. A long-slope runoff plot with 5 m wide and 320 m long located in the typical Mollisol region of China was divided into eight segments, each of which was 40 m long and tagged with one of eight REE oxides. The spot method of a partial-area tagging scheme was employed and a grid-based layout was used for REE application. Results showed that annual soil erosion rate was 3251.0 t km−2 for the whole runoff plot, in which snowmelt runoff erosion contributed 537.3 t km−2, wind erosion 363.1 t km−2 and rainfall-runoff erosion 2350.6 t km−2. Surface runoff is the main external erosive force of hillslope soil erosion, accounting for 88.8% of the total annual soil loss. Furthermore, for the eight slope segments of the 320-m long hillslope, the sediment transport ratios of each slope segment caused by snowmelt runoff and rainfall-runoff erosion were more than 23.5% and 34.7%, respectively. The results will enrich the understanding of seasonal soil erosion on long hillslopes

Chemical Reaction Spectrum: A Holographic Image for Characterizing Multi-component Chemical Mixtures

Abstract: Multi-component chemical mixtures (MCMs) and their various effects always concerned in analytical chemistry, but current analytical techniques based on test-tube experiments often involves many high-cost and laborious operations. Today’s pop machine-learning (ML) technology has exhibited their successes in dealing with the analysis task of various complex systems. Predictably, the introduction of ML will radically accelerate the exploration of many fields involving mixture analysis. But the biggest challenge ahead for this process is how to provide some intelligible and sufficient data for various algorithms. In this study, we proposed a chemical imaging strategy to visualize various mixtures as some feature images by using ink-jet printing technology based on combinatorial chemistry. Here, these feature images were as a novel data form of chemical reaction spectrum (CRS), which can comprehensively describe and record the reaction characteristics of the complex sample. Compared with common imaging methods, the CRS with high-throughput chemical reaction dots is an efficient and economic information visualization way for the MCM sample. It is expected to be an important data acquisition approach for the application of ML in the field of chemistry in future

Impacts of Animal Herbivory and Water Depth on Seed Germination and Seedling Survival of Vallisneria natans (Lour.) Hara and Hydrilla verticillata (L. f.) Royle

Seed germination is an important reproductive pattern for submerged macrophytes. In order to investigate the effects of animal herbivory and water depth on seed germination and seedling survival of Vallisneria natans and Hydrilla verticillata, we conducted an in-situ field experiment at 3 water depths (0.5, 1, and 2 m) with net and non-net (control) groups in Hangzhou West Lake, China. The results showed that the highest germination rates appeared at 1 m water depth and the lowest germination rates appeared at 2 m water depth (p&lt;0.05) for both species. The mean time to germination (MTG) values that indicate the velocity of germination are greater at 2 m water depth than that at 0.5 m and 1 m water depths for both V. natans and H. verticillata. Net protection obviously promoted germination rates of both species at 0.5 m and 1 m depths, especially for H. verticillata at 1 m (p&lt;0.05). Germination rates of H. verticillata were higher than that of V. natans under any treatment (p&lt;0.05). In the control, seedlings of both species were greatly grazed by herbivorous animals and the remaining seedling number showed no significant difference at different depths (p&gt;0.05). Remaining seedling number in net group was significantly higher than that in control group (p&lt;0.05). Grazing rate of H. verticillata was significantly higher than that of V. natans in control group at all 3 depths (p&lt;0.05). Conclusively, both water depth and animal herbivory significantly influenced germination of V. natans and H. verticillata, and net protection proved to be an efficient method that could promote seedling survival for both species in the field.</p

Investigation on the adsorption of phosphorus in all fractions from sediment by modified maifanite

Sediment phosphorus (P) removal is crucial for the control of eutrophication, and the in-situ adsorption is an essential technique. In this study, modified maifanite (MMF) prepared by acidification, alkalization, salinization, calcination and combined modifications, respectively, were first applied to treat sediment P. The morphology and microstructure of MMF samples were characterized by X-ray fluorescence (XRF), Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and Brunauer-Emmett-Teller (BET). Various adsorption parameters were tested, such as dosage of maifanite, time, operation pH and temperature. The adsorption mechanisms were also investigated and discussed. Results showed that CMMF-H2.5-400 (2.5 mol/L H2SO4 and calcined at 400 degrees C) exhibited the highest P adsorption capacity. Thus, it was selected as the in-situ adsorbent material to control the internal P loading. Under the optimal conditions of dynamic experiments, the adsorption rates of TP, IP, OP, Fe/Al-P and Ca-P by CMMF-H2.5-400 were 37.22%, 44.41%, 25.54%, 26.09% and 60.34%, respectively. The adsorption mechanisms analysis revealed that the adsorption of P onto CMMF-H2.5-400 mainly by ligand exchange. Results of this work indicated that the modification treatment could improve the adsorption capacity of maifanite, and CMMF-H2.5-400 could be further applied to eutrophication treatment

Aluminum distribution heterogeneity and relationship with nitrogen, phosphorus and humic acid content in the eutrophic lake sediment

Increasing amount of aluminum (Al) gets into aquatic ecosystem through anthropogenic activity, but the knowledge about Al migration and relationships with sediments possessing different physico-chemical properties in eutrophic lakes is limited. Here, the Al migration rule and relationships with sediment nutritions in the Hangzhou West Lake, China was investigated, where a certain amount of residual Al-salts can enter because of the pre-treatment of the Qiantang River diversion project every day. Results revealed the obvious spatial distribution heterogeneity of Al in sediment vertical direction and horizontal direction following water flow. The Al content in sediment ranged 0.463-1.154 g kg(-1) in Maojiabu Lake, and ranged 9.862-40.442 g kg(-1) in Xiaonanhu Lake. Higher Al content distributed in upper layer sediment in lake with more disturbance. Total nitrogen (TN) contents were higher 0.917-3.387 mg g(-1) and 0.627-0.786 mg g(-1) in upper layer sediment than that in lower layer in Maojiabu Lake and Xiaonanhu Lake, respectively. Total phosphorus (TP) content ranged 0.779-2.580 mg g(-1), in which IP and Fe/Al-P contributed 24.9-80.8% and 17.0-51.6%, respectively. Correlations between Al content with nutrition, humic acid (HA) etc. of sediment regionally varied in Maojiabu and Xiaonanhu Lake. Spatial distribution of Al-salt in eutrophic lakes closely related with the physico-chemical characteristics of nutrients, humus, human disturbance and water division parameters. Results provides new insight into Al-salts migration and references for Al-risk evaluating in eutrophic lakes. (C) 2019 Elsevier Ltd. All rights reserved

Effects of aluminate flocculant on turion germination and seedling growth of Potamogeton crispus

Aluminate flocculants are employed widely in water treatment for precipitating suspended solids and emergency treatment of algal blooms in eutrophic lake, but the residual aluminum (Al) may have phytotoxic effects on aquatic organisms after entering aquatic ecosystems. To elucidate the potential impacts of Al on turion germination and early growth in Potamogeton crispus, we conducted a mesocosm experiment using five Al concentrations (0 (control group), 0.3, 0.6, 1.2, and 1.5 mg/L) in alum solutions. The results showed that the germination of turions and the early growth of P. crispus were reduced and inhibited by Al. The maximum numbers of germinating turions and newly-formed seedlings occurred in the control group, and their numbers declined in the end of the experiment as the Al concentration increased. Al at a concentration of 1.5 mg/L decreased the number of germinating turions 3.0 times and the number of newly-formed seedlings 30.7 times compared with the control. The chlorophyll content and root activity decreased when the Al concentration increased. The maximum soluble protein contents in seedling tissues (1.953 mg/g fresh weight) occurred in the 0.6 mg/L treatment group, which differed significantly from the other treatment groups. The Al contents in the seedling tissues had a significant positive correlation with the Al treatment concentrations (P &lt; 0.05, r = 0.763), but negative correlations with the biomass, root number, stem weight, soluble protein, and root activity (r = -0.935, -0.975, -0.907, -0.721, -0.944, respectively). Persistent Al concentration 1.2 mg/L significantly decreased the germination of turions and seedling growth in P. crisp us. These results may facilitate the restoration of aquatic macrophytes and ecological risk assessments in Al-exposed lakes