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Effects of CO2 Fumigation and Nitrogen Addition on Soil Respiration in a Wetland Ecosystem : Experimental Approach with Top Open Chambers

Wang J., Fu X., Wang J., Zhong H., Zhang R., Ni H.

Polish Journal of Ecology

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2018

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Vol. 66, nr 2

102--113

EN

Soil respiration plays a crucial role in global carbon cycling of terrestrial ecosystems. Changes in atmospheric CO2 and nitrogen (N) addition across the globe are likely to affect soil respiration. However, the effects of elevated CO2, and N addition on soil respiration are not fully understood especially in wetland ecosystems. To evaluate the effects of atmospheric CO2 and N availability on soil respiration, a paired, nested manipulative in situ experiment was performed, using CO2 fumigation within Open-Top Chambers as the primary factor, and N (as NH4NO3) as the secondary factor in a temperate wetland in northeastern China in 2010 and 2011. CO2 fumigation significantly enhanced soil respiration, according to repeated-measures ANOVA, and the stimulatory effect of CO2 fumigation on soil respiration was sustained during the whole experimental period regardless of N addition. However, the positive soil respiration effect of N addition alone weakened over time. Moreover, there was a significant interaction between CO2 fumigation and N addition. Soil temperature explained 50-66% of the variation in soil respiration. Moreover, soil respiration was positively correlated with the root N content and litter decomposition rate. The results suggested that elevated CO2 concentrations will accelerate soil respiration and ecosystem carbon cycling, thus, limiting soil carbon sequestration, especially when coupled with increasing N deposition.

2

Study on a novel hydroxamic acid as the collector of rhodochrosite

Zhao G., Dai T., Wang S., Zhong H.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 2

428--439

EN

A novel collector, tert-butyl benzohydroxamic acid (TBHA), was first introduced in rhodochrosite flotation. The performance of TBHA was investigated by the density functional theory (DFT) calculation along with the micro flotation test, zeta potential determination and XPS analysis, compared with benzohydroxamic acid (BHA). TBHA has stronger affinity to the mineral than BHA in terms of frontier molecular orbital, atomic net charge and bond population. The substitution of tert-butyl group on the benzene ring improves the affinity of the hydroxamic acid to the mineral. TBHA exhibits excellent collecting ability to rhodochrosite with a recovery of about 99% at a concentration of 3.89×10-4 mol/dm3 and pH 6.5. The hydroxamic acid molecules are adhered on mineral surfaces by chemical adsorption, resulting in negative shifts for the zeta potential of rhodochrosite with the presence of the collector. Chemical adsorption can be also confirmed from XPS analyses that the atomic concentration ratios of C and O to Mn on the treated mineral surfaces were increased and the binding energy of Mn3s was decreased. The experimental data achieve excellent agreement with the computational analyses.

3

Kinetics and mechanism of one-step reductive leaching of manganese oxide ores by EDTA/EDTA-2Na

Zhang C., Wang S., Cao Z., Zhong H.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 3

858--867

EN

In this research, the kinetics and mechanism of one-step reductive leaching of manganese oxide ores by ethylenediaminetetraacetic acid (EDTA) or its disodium salt (EDTA-2Na) in an aqueous medium have been investigated. The kinetic data of this reductive leaching process may be described by the Avrami model, and the apparent activation energy was determined to be 15.8 kJ·mol-1/7.9 kJ·mol-1 for leaching by EDTA/EDTA-2Na with a reaction order of -1.7/2.0. The EDTA/EDTA-2Na leach liquor characterized and analyzed by X-ray photoelectron spectra (XPS), Fourier transform infrared spectra (FTIR), and total organic carbon (TOC) determination denoted that the oxidation-reduction reaction happened between manganese(IV) and EDTA/EDTA-2Na, and a coordination complex, EDTA-manganese(II/III) formed. This new process can be easily used to leach manganese from manganese oxide ores in a moderate environment with the pH range of 5–8.

4

Attribute-based Data Integrity Checking for Cloud Storage

Tian M., Wang L., Zhong H., Chen J.

Fundamenta Informaticae

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2018

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Vol. 163, nr 4

395--411

EN

Cloud storage is a significant service provided by the cloud that enables users to store their immense data into the cloud. As the advent of the big data era, cloud storage services are becoming increasingly popular. For security reasons, data owners would like to check the integrity of their data after storing it in the cloud. To do this, they usually make use of the public cloud data integrity checking schemes. This paper focuses on user anonymity in such schemes so that no third party could infer the identity information of any data owner from checking procedures. The problem is obviously inevitable in reality, however the current solutions are relatively involved as they heavily use public key certificates and/or incur huge communication overhead. In this paper we introduce the concept of attribute-based cloud data integrity checking to achieve user anonymity lightly and present security models for such systems. We also provide a practical construction and prove its security in the random oracle model. Finally, we show how to extend our construction to protect data privacy against any third party.

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Collaborative intelligence - definition and measured impacts on internetworked e-work

Zhong H., Levalle R. R., Moghaddam M., Nof S. Y.

Management and Production Engineering Review

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2015

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Vol. 6, No. 1

67--78

EN

Internetworked e-Work is enabling new channels in cyber space for collaboration among physical and cyber agents, e.g., humans, robots, software agents. Research on Collaborative Control Theory (CCT) indicates that building and augmenting the Collaborative Intelligence (CI) of participants in cyber-physical networks can provide better support for achieving their individual and common goals. In spite of its rising significance and popularity, however, no clear and precise definition and universal quantitative measure has been proposed for the CI. In this article, we first formalize the CI by suggesting a formal definition, based on the definitions of its elements - collaboration and intelligence. We then propose a quantitative measure for the CI, adapted from the universal intelligence measure. For illustration, we analyze three recent collaborative e-Work studies at three different scales: (1) Telerobotenabled computer supported collaborative design; (2) Collaborative product line control in supply networks; (3) Demand and capacity sharing in multi-enterprise collaboration. From these case studies, common advantages such as work efficiency, network robustness and stability, service level, resource utilization, and collaboration cost are observed, analyzed, and translated into formal CI measures. Results indicate significant impacts of CI on the efficiency, effectiveness, and quality of collaborative activities in emerging e-Work networks.