Synergistic removal of U(VI) from aqueous solution by TAC material: Adsorption behavior and mechanism.

The adsorption and recovery of uranium from wastewater is of positive significance to the development of nuclear industry and environmental remediation. The ternary polymer (PZS-co-TA) was prepared from hexachlorocyclotriphosphazene (HCCP), 4,4-sulfonyldiphenol (BPS) and tannic acid (TA) under ultrasonic. TAC was then obtained after carbonization under high temperature from PZS-co-TA. The structure and performance of TAC were analyzed using SEM, EDS, FT-IR, XRD, Raman, BET and TG. The adsorption capacity of TAC for uranium under different static adsorption conditions was investigated. The adsorption process was more consistent with pseudo-second-order model. The maximum adsorption capacity calculated by non-linear Langmuir model was 492.5 mg/g at pH 5.5. The thermodynamic values suggested that the adsorption process was spontaneous and endothermic. Moreover, after five cycles of adsorption-desorption tests, TAC remained effective at adsorbing uranium, implying the introducing of TA to the precursor (PZS-co-TA) could enhance the adsorption capacity for uranium.

Cognitive Control-Loop for Elastic Optical Networks with Space-Division Multiplexing.

This paper introduces a new solution to improve network performance by decreasing spectrum fragmentation, crosstalk interference, blocking of virtual networks, cost, and link load imbalance. These problems degrade the performance of Elastic Optical Networks with Space-Division Multiplexing. The proposed solution, called Cognitive control loop (CO-OP), is capable of identifying a set of problems and creating plans to mitigate these problems. The CO-OP comprises four functions that employ learning algorithms to identify problems and plan a series of actions to reduce or eliminate them. The results show that the CO-OP can effectively decrease up to 30% the blocking of requests and up to 50% the crosstalk occurrence compared to existing algorithms.

Demonstration of distributed collaborative learning with end-to-end QoT estimation in multi-domain elastic optical networks.

This paper proposes a distributed collaborative learning approach for cognitive and autonomous multi-domain elastic optical networking (EON). The proposed approach exploits a knowledge-defined networking framework which leverages a broker plane to coordinate the operations of multiple EON domains and applies machine learning (ML) to support autonomous and cognitive inter-domain service provisioning. By employing multiple distributed ML blocks learning domain-level features and working with broker plane aggregation ML blocks (through the chain rule-based training), the proposed approach enables to develop cognitive networking applications that can fully exploit the multi-domain EON states while obviating the need for the raw and confidential intra-domain data. In particular, we investigate end-to-end quality-of-transmission estimation application using the distributed learning approach and propose three estimator designs incorporating the concepts of multi-task learning (MTL) and transfer learning (TL). Evaluations with experimental data demonstrate that the proposed designs can achieve estimation accuracies very close to (with differences less than 0.5%) or even higher than (with MTL/TL) those of the baseline models assuming full domain visibility.

Demonstration of application-driven network slicing and orchestration in optical/packet domains: on-demand vDC expansion for Hadoop MapReduce optimization.

Nowadays, it is common for service providers (SPs) to leverage hybrid clouds to improve the quality-of-service (QoS) of their Big Data applications. However, for achieving guaranteed latency and/or bandwidth in its hybrid cloud, an SP might desire to have a virtual datacenter (vDC) network, in which it can manage and manipulate the network connections freely. To address this requirement, we design and implement a network slicing and orchestration (NSO) system that can create and expand vDCs across optical/packet domains on-demand. Considering Hadoop MapReduce (M/R) as the use-case, we describe the proposed architectures of the system's data, control and management planes, and present the operation procedures for creating, expanding, monitoring and managing a vDC for M/R optimization. The proposed NSO system is then realized in a small-scale network testbed that includes four optical/packet domains, and we conduct experiments in it to demonstrate the whole operations of the data, control and management planes. Our experimental results verify that application-driven on-demand vDC expansion across optical/packet domains can be achieved for M/R optimization, and after being provisioned with a vDC, the SP using the NSO system can fully control the vDC network and further optimize the M/R jobs in it with network orchestration.

Experimental demonstration of building and operating QoS-aware survivable vSD-EONs with transparent resiliency.

Software-defined elastic optical networks (SD-EONs) provide operators more flexibility to customize their optical infrastructures dynamically. By leveraging infrastructure-as-a-service (IaaS), virtual SD-EONs (vSD-EONs) can be realized to further enhance the adaptivity of SD-EONs and shorten the time-to-market of new services. In this paper, we design and demonstrate the building and operating of quality-of-service (QoS) aware survivable vSD-EONs that are equipped with transparent data plane (DP) resiliency. Specifically, when slicing a vSD-EON, our network hypervisor (NHV) chooses to use "1:1" virtual link (VL) protection or on-demand VL remapping as the DP restoration scheme, according to the service-level agreement (SLA) between the vSD-EON's operator and the infrastructure provider (InP). Then, during an actual substrate link (SL) failure, the NHV realizes automatic DP restoration that is transparent to the controllers of vSD-EONs. We build a network testbed to demonstrate the creation of QoS-aware survivable vSD-EONs, the activation of lightpaths in the vSD-EONs to support upper-layer applications, and the automatic and simultaneous QoS-aware DP restorations during an SL failure. The experimental results indicate that our vSD-EON slicing system can build QoS-aware survivable vSD-EONs on-demand, operate them to set up lightpaths for carrying real application traffic, and facilitate differentiated DP restorations during SL failures to recover the vSD-EONs' services according to their SLAs.

Time Course of Carbendazim Stimulation on Pathogenicity of Sclerotinia sclerotiorum Indicates a Direct Stimulation Mechanism.

Previous studies have demonstrated that subtoxic doses of carbendazim have a stimulatory effect on pathogenicity of Sclerotinia sclerotiorum on rapeseed plants. The present study focused on the time-course profile of the stimulatory effect and its relevance to stimulation mechanisms. At 12 h postinoculation (HPI), initial necrotic lesions were visible only for rapeseed leaves treated with carbendazim at 0.2 and 1 µg/ml, whereas no disease symptoms were observed for the nontreated control. At 18 HPI, carbendazim stimulation on pathogenicity was more obvious than at 12 HPI. Study with scanning electron microscopy demonstrated that no discernable differences in the development of disease symptoms could be detected at 8 HPI. However, at 12 HPI, necrotic symptoms of the epidermal cells were apparent only for leaves sprayed with carbendazim. These results indicated that stimulations on pathogenicity occurred in the first 12 h, implying that direct stimulation rather than overcompensation to the disruption of homeostasis was likely to be the underlying mechanism for pathogenicity stimulation. Greenhouse experiments showed that spraying carbendazim at 400 µg/ml on potted rapeseed plants had statistically significant (P < 0.05) stimulations on pathogenicity for inoculations at 1, 3, 5, and 7 days after application (DAA). The stimulation action eventually disappeared for inoculations at 14 DAA. Mycelia grown on potato dextrose agar (PDA) supplemented with carbendazim at 400 µg/ml were more pathogenic than the nontreated control. However, after additional growth of the mycelia on fungicide-free PDA for 2 days, the stimulatory effect disappeared completely, indicating that carbendazim was indispensable for pathogenicity stimulations. Studies on biochemical mechanisms indicated that cell-wall-degrading enzymes such as cellulase, pectinase, and polygalacturonase were not involved in pathogenicity stimulations. These results will advance our understanding of the nature and mechanisms of fungicide stimulation on fungal pathogenicity and, thus, are valuable for judicious applications of fungicides.

Fragmentation-aware service provisioning for advance reservation multicast in SD-EONs.

In this paper, we study the service provisioning schemes for dynamic advance reservation (AR) multicast requests in elastic optical networks (EONs). We first propose several algorithms that can handle the service scheduling and routing and spectrum assignment (RSA) of AR multicast requests jointly, including an integrated two-dimensional fragmentation-aware RSA (2D-FMA) that can alleviate the 2D fragmentation caused by light-tree provisioning. Then, we leverage the idea of software-defined EONs (SD-EONs) that utilizes OpenFlow (OF) in the control plane to demonstrate and evaluate the proposed algorithms. Specifically, we build an SD-EON control plane testbed, implement the algorithms in it, and perform control plane experiments on dynamic AR multicast provisioning. The results indicate that 2D-FMA achieves the best blocking performance and provides the shortest average setup delay.

Leveraging master-slave OpenFlow controller arrangement to improve control plane resiliency in SD-EONs.

In this paper, we study how to improve the control plane resiliency of software-defined elastic optical networks (SD-EONs) and design a master-slave OpenFlow (OF) controller arrangement. Specifically, we introduce two OF controllers (OF-Cs), i.e., the master and slave OF-Cs, and make them work in a collaborative way to protect the SD-EON against controller failures. We develop a controller communication protocol (CCP) to facilitate the cooperation of the two OF-Cs. With the CCP, the master OF-C (M-OF-C) can synchronize network status to the slave OF-C (S-OF-C) in real time, while S-OF-C can quickly detect the failure of M-OF-C and take over the network control and management (NC&M) tasks timely to avoid service disruption. We implement the proposed framework in an SD-EON control plane testbed built with high-performance servers, and perform NC&M experiments with different network failure scenarios to demonstrate its effectiveness. Experimental results indicate that the proposed system can restore services in both the data and control planes of SD-EON jointly while maintaining relatively good scalability. To the best of our knowledge, this is the first demonstration that realizes control plane resiliency in SD-EONs.

Pathogenicity Stimulation of Sclerotinia sclerotiorum by Subtoxic Doses of Carbendazim.

Sclerotinia sclerotiorum is a devastating ascomycete fungus capable of infecting more than 400 species of plants worldwide. Carbendazim has been a principal fungicide for control of this pathogen and high levels of carbendazim resistance have been reported in eastern China. In this study, stimulatory effect of subtoxic doses of carbendazim on pathogenicity of S. sclerotiorum was investigated. All seven field resistant isolates with EC50 values greater than 1,000 µg/ml exhibited stimulated pathogenicity toward detached leaves of rapeseed at subtoxic concentrations of carbendazim. Detailed studies on pathogenicity of two resistant isolates AH-17 and LJ-86 toward potted rapeseed plants and detached leaves demonstrated that carbendazim at 0.2 to 5 µg/ml could consistently stimulate significantly higher (P < 0.05) pathogenicity than the control. On potted rapeseed plants, the percent stimulations on pathogenicity ranged from 18.8 to 22.0% for isolate AH-17 and from 15.1 to 23.2% for isolate LJ-86. On detached leaves of rapeseed, the percent stimulations ranged from 18.7 to 31.29% for isolate AH-17 and from 16.7 to 24.3% for isolate LJ-86. Studies on stimulation mechanism indicated that secretion of oxalic acid and tolerance to oxidative stresses H2O2 and paraquat after exposed to subtoxic doses of carbendazim did not change significantly. These results have profound implications for judicious application of fungicides and sustainable management of fungicide resistance.