Sulfur Flotation Performance Recognition Based on Hierarchical Classification of Local Dynamic and Static Froth Features

© 2018 IEEE. This paper proposes a flotation performance recognition system based on a hierarchical classification of froth images using both local dynamic and static features, which includes a series of functions in image extraction, processing, and classification. Within the integrated system, to identify the abnormal working condition with poor flotation performance (NB it could be significantly different with the dynamic features of the froth in abnormal working condition), it is functioned first with building up local dynamic features of froth image from the information including froth velocity, disorder degree, and burst rate. To enhance the dynamic feature extraction and matching, this system introduces a scale-invariant feature transform method to cope with froth motion and the noise induced by dust and illumination. For the performance subdividing under normal working conditions, bag-of-words (BoW) description is utilized to fill the semantic gap in performance recognition when images are directly described by global image features. Accordingly typical froth status words are extracted to form a froth status glossary so that the froth status words of each patch form the BoW description of an image. A Bayesian probabilistic model is built to establish a froth image classification reference with the BoW description of images as the input. An expectation-maximization algorithm is used for training the model parameters. Data obtained from a real plant are selected to verify the proposed approach. It is noted that the proposed system can reduce the negative effects of image noise, and has high accuracy in flotation performance recognition

Hexokinase1: A glucose sensor involved in drought stress response and sugar metabolism depending on its kinase activity in strawberry

Hexokinase1 (HXK1) is a bifunctional enzyme that plays indispensable roles in plant growth, nitrogen utilization, and stress resistance. However, information on the HXK family members of strawberries and their functions in glucose sensing and metabolic regulation is scarce. In the present study, four HXKs were firstly identified in the genome of Fragaria vesca and F. pentaphylla. The conserved domains of the HXK1s were confirmed, and a site-directed mutation (S177A) was introduced into the FpHXK1. FpHXK1, which shares the highest identity with the AtHXK1 was able to restore the glucose sensitivity and developmental defects of the Arabidopsis gin2-1 mutant, but not its kinase-activity-impaired mutant (FpHXK1S177A). The transcription of FpHXK1 was dramatically up-regulated under PEG-simulated drought stress conditions. The inhibition of the HXK kinase activity delayed the strawberry plant’s responses to drought stress. Transient overexpression of the FpHXK1 and its kinase-impaired mutant differentially affected the level of glucose, sucrose, anthocyanins, and total phenols in strawberry fruits. All these results indicated that the FpHXK1, acting as a glucose sensor, was involved in drought stress response and sugar metabolism depending on its kinase activity

Green Synthesis of Iron Nanoparticles Using Green Tea and Its Removal of Hexavalent Chromium

Chromium (VI) is a ubiquitous groundwater contaminant and it is dangerous to both ecological and human health. Iron nanoparticles (nFe) have a large specific surface area and they are highly efficient in removing chromium (VI) from aqueous solution. However, since the traditional reductive synthesis of nFe is relatively expensive and often causes secondary pollution, it is necessary to develop a low-cost green synthetic method using plant extracts. Synthetic conditions are important for obtaining highly active chromium-removing nanomaterials. In this paper, a green tea extract was used to prepare nFe and the effects of synthetic conditions on subsequent remediation performance were investigated. The optimal conditions included a green tea extract/Fe2+ ratio of 1:2 (91.6%), a green tea extract temperature of 353 K (88.3%) and a synthetic temperature of 298 K (88.1%). Advanced material characterization techniques, including XPS, SEM-EDS, TEM, and Brunauer–Emmett–Teller (BET) confirmed that the average particle size was between 50–80 nm, with a specific surface area of 42.25 m2·g−1. Furthermore nFe had a core-shell structure, where Fe (0) constituted the core and a shell was composed of iron oxide. Finally, a mechanism for synthesizing nFe by green tea extract was proposed, providing a theoretical basis for optimized synthetic conditions for preparing nFe when using green tea extract

Green Synthesis of Iron Nanoparticles Using Green Tea and Its Removal of Hexavalent Chromium

Chromium (VI) is a ubiquitous groundwater contaminant and it is dangerous to both ecological and human health. Iron nanoparticles (nFe) have a large specific surface area and they are highly efficient in removing chromium (VI) from aqueous solution. However, since the traditional reductive synthesis of nFe is relatively expensive and often causes secondary pollution, it is necessary to develop a low-cost green synthetic method using plant extracts. Synthetic conditions are important for obtaining highly active chromium-removing nanomaterials. In this paper, a green tea extract was used to prepare nFe and the effects of synthetic conditions on subsequent remediation performance were investigated. The optimal conditions included a green tea extract/Fe2+ ratio of 1:2 (91.6%), a green tea extract temperature of 353 K (88.3%) and a synthetic temperature of 298 K (88.1%). Advanced material characterization techniques, including XPS, SEM-EDS, TEM, and Brunauer–Emmett–Teller (BET) confirmed that the average particle size was between 50–80 nm, with a specific surface area of 42.25 m2·g−1. Furthermore nFe had a core-shell structure, where Fe (0) constituted the core and a shell was composed of iron oxide. Finally, a mechanism for synthesizing nFe by green tea extract was proposed, providing a theoretical basis for optimized synthetic conditions for preparing nFe when using green tea extract

N2O emissions and product ratios of nitrification and denitrification are altered by K fertilizer in acidic agricultural soils

Potassium (K) fertilizer plays an important role in increasing crop yield, quality, and nitrogen use efficiency. However, little is known about its environmental impacts, such as its effects on emissions of the greenhouse gas nitrous oxide (N2O). A nitrogen-15 (N-15) tracer laboratory experiment was therefore performed in an acidic agricultural soil in the suburbs of Wuhan, central China, to determine the effects of K fertilizer on N2O emissions and nitrification/denitrification product ratios under N fertilization. During 15-d incubation periods with a fixed initial N concentration (80 mg kg(-1)), K application increased average N2O emission rates significantly (1.6-10.8-fold) compared to the control treatment. N2O emissions derived from nitrification and denitrification both increased in K-treated soil, and denitrification contributed more to the increase; its contribution ratio rose from 32% without K fertilizer to 53% with 300 mg kg(-1) of K applied. The increase in N2O emissions under K fertilization is probably due to an increase in the activity of denitrifying microorganisms and acid-resistant nitrifying microorganisms caused by higher K+ concentrations and lower soil pH. Combined treatment with potassium chloride (KCl) and N fertilizer produced lower N2O emissions than combined treatment with potassium sulfate (K2SO4) and N fertilizer during 15-d incubation periods. Our results imply that there are significant interaction effects between N fertilizers and K fertilizers on N2O emissions. In particular, combining N fertilizers with fertilizers that reduce soil acidity or contain Cl or K ions may significantly affect agricultural N2O emissions. (C) 2020 Elsevier Ltd. All rights reserved

Phosphorus spatial distribution and pollution risk assessment in agricultural soil around the Danjiangkou reservoir, China

The phosphorus (P) content in agricultural soils in catchments of lakes or rivers is an important issue because P is both an essential nutrient for high plant yields and a major contributor to eutrophication of water bodies. Thus, we have assessed the spatial distribution of soil P, impacts of environmental factors on its spatial variation, and associated pollution risks, in farmland around the Danjiangkou Reservoir, China. A total of 217 sites were sampled, including 121, 44 and 52 in dry cropland, paddy land and orchards, respectively. Total phosphorus (TP) contents in the sampled soils ranged from 0.230 to 1.893 g kg(-1) and Olsen-P (a measure of available P) from 0.38 to 176 mg kg(-1) . Soil TP and Olsen-P had moderate and high variability, with coefficients of variation of 40% and 115%, respectively. Geostatistical analysis showed that both TP and Olsen-P had positive nugget effects, but TP had stronger spatial autocorrelations than Olsen-P (nugget-to-sill ratios: 22 and 50%, respectively). Total P was significantly influenced by temperature, elevation, aspect, soil pH, organic matter and precipitation, while Olsen-P was controlled by aspect and land use. The TP in soil was very similar in dry cropland and orchards (0.64 +/- 0.19 and 0.61 +/- 0.23 g kg(-1) , respectively), but substantially lower in paddy land (0.15 +/- 0.25 g kg(-1)). Risks for P loss appeared to be very high, high, moderate and low in approximately 10, 40, 15 and 30% of the farmland in the Danjiangkou reservoir area, respectively. (C) 2019 Elsevier B.V. All rights reserved

Structure and phase analysis of one-pot hydrothermally synthesized FePO4-SBA-15 as an extremely stable catalyst for harsh oxy-bromination of methane

FePO4-SBA-15 (OP) was directly synthesized via a one-pot hydrothermal technique, using Fe(NO3)(3) and H3PO4 as the precursors. FePO4/SBA-15 (IMP) was also prepared as a reference, using an impregnation method and commercially available SBA-15 as the support. The yielding samples were employed to catalyze the harsh oxy-bromination of methane (OBM) reaction, showing similar initial catalytic performances. The fresh and spent samples after catalytic reaction were thoroughly characterized by N-2-physisoption, inductively coupled plasma, wide- and small-angle X-ray diffraction, transmission electron microscopy, diffuse reflectance UV-vis spectroscopy, temperature-programmed oxidation, and room temperature Fe-57 Mossbauer spectroscopy. It was found that the FePO4 was in good crystalline in the OP sample while it was in amorphous for the IMP catalyst. Despite this difference, both FePO4 phases in the fresh samples were transformed into Fe-2(PO4)(6) and Fe2P2O7 in the spent ones. Furthermore, the OP catalyst showed excellent stability in a period of 1000 h time-on-stream performance without apparent deposition of cokes. The losses of P and Fe after the catalytic evaluation were only 9.5% and 15.5%, respectively, while the ratio of P/Fe remained close to 1.0. N-2-adsorption and TEM observations confirmed that the mesoporous pores were extremely stable under the harsh reaction ambience, which might play a crucial role in the stability test. (C) 2012 Elsevier B.V. All rights reserved

Interactions between N, P and K fertilizers affect the environment and the yield and quality of satsumas

The balance between crop yield, quality and soil nutrient status can be manipulated by exploiting nutrient interactions. Field experiments were conducted in citrus orchards in Danjiangkou, Hubei Province to assess the effects of N (0, 0.3, 0.6 and 0.9 kg plant (-1)), P (0, 0.1, 0.2, 0.3 kg plant (-1)), K (0, 0.15, 0.30, 0.45 kg plant (-1)) and their interactions on residual nutrient content in soils, and the yield and quality of satsumas. The results showed that the effects of N and K fertilizers on the yield and quality of satsumas were greater than those of P fertilizers. Appropriate application rates of N (0.6 kg plant (-1)), P (0.3 kg plant(-1)) and K (0.15 kg plant(-1)) significantly improved yield and quality. Lack or excess or inappropriate ratios of N, P and K fertilizer can affect the absorption and utilization of nutrients and reduce yield and quality. The best fertilizer combination, determined by comprehensively considering yield, quality and environment, was N0.3P0.2K0.3, which delivered moderate yield, high fruit quality and low potential risk of pollution. The amount of fertilizer in this case was 0.3 kg N, 0.2 kg P, 0.3 kg K per plant, which is lower than the current recommended application rates (0.5-0.8 kg N, 0.2-0.5 kg P, 0.25-0.64 kg K, respectively). The economic benefit did not decrease because of a decline of yield, but increased slightly because of the improved fruit quality and the reduction in fertilizer input, compared with the treatment with the highest yield. Therefore, we suggest that it is necessary to consider the quality of agricultural products and environmental protection when applying fertilizer and to reduce N and P fertilizer input and appropriately increase the proportion of K. (C) 2019 The Authors. Published by Elsevier B.V

Gramineae-legumes mixed planting effectively reduces soil and nutrient loss in orchards

Soil, water, and nutrients depletion may affect sustainable agriculture in some resource-poor areas. Implementing cover crops as a conservation management strategy mitigates the loss of water, soil, nitrogen (N), and phosphorus (P) by introducing vegetation during non-crop seasons or in the spaces between rows instead of leaving the land bare. This study aimed to compare water, soil, various carbon (C) forms, N, and P losses through leaching and surface runoff in orchard fields that were managed with either no-cover crop (NC) or cover crops, including natural grass (NG), Legume grass (LG), Gramineae grass (GG), and a mixture of Legume and Gramineae grass (MG). The findings indicate that cover crop fields exhibited a significant reduction in the runoff by 33–60 %, leaching amount by 33–51 %, soil loss by 30–53 %, and total C, N, and P by 30–48 %, 30–49 %, and 30–38 %, respectively compared to NC fields. Additionally, implementing artificial grass, particularly MG, demonstrated more significant efficacy in mitigating water and soil losses and associated N and P losses. Specifically, MG fields exhibited a 40 % and 18 % reduction in runoff and leaching as well as a reduction in total C, N, and P loss by 7 %, 12 %, and 7 %, respectively, compared to NG fields. The LG field experienced a 50 % more significant N loss than the MG field, whereas the GG runoff exhibited an increase of more than 70 %. Implementing MG coverage has significantly reduced soil erosion and consequent nutrient loss, establishing it as a viable and uncomplicated approach to conserving soil and water in orchards

Metabolomic Analysis Revealed Distinct Physiological Responses of Leaves and Roots to Huanglongbing in a Citrus Rootstock

Huanglongbing (HLB) is an obstinate disease in the citrus industry. No resistant citrus resources were currently available, but various degrees of Huanglongbing tolerance exist in different germplasm. Citrus junos is emerging as one of the popular rootstocks widely used in the citrus production. However, its responses to the HLB causal agent, Candidatus Liberibacter asiaticus (CLas), were still elusive. In the current study, we investigated the physiological, anatomical, and metabolomic responses of a C. junos rootstock ‘Pujiang Xiangcheng’ by a controlled CLas grafting inoculation. The summer flushes and roots were impaired at 15 weeks after inoculation, although typical leaf symptomatic phenotypes were not obvious. The chlorophyll pigments and the photosynthetic rate were compromised. The phloem sieve tubes were still working, despite the fact that the callose was deposited and the starch granules were accumulated in the phloem cells. A wide, targeted metabolomic analysis was carried out to explore the systematic alterations of the metabolites at this early stage of infection in the leaves and root system. The differentially accumulated metabolites in the CLas-affected leaves and roots compared with the mock-inoculation control tissues revealed that distinct responses were obvious. Besides the commonly observed alteration of sugar and amino acids, the active break down of starch in the roots was discovered. The different types of fatty acids were altered in the two tissues, with a more pronounced content decline in the roots. Our results not only provided fundamental knowledge about the response of the C. junos rootstock to the HLB disease, but also presented new insights into the host–pathogen interaction in the early stages