Effect of vacuum annealing on field emission from heavily phosphorus doped homoepitaxial (111) diamond

Vacuum anneal treatments effects on field emission properties of phosphorus doped diamond are discussed. The C1s core level of diamond is characterized by X-ray photoelectron spectroscopy (XPS). With increasing annealing temperature, firstly oxygen desorption takes place from surface, which induce surface reconstruction followed by graphitization of surface. Field emission properties, therefore, strongly depend on vacuum anneal temperature. The threshold voltage of diamond annealed at 900 °C is the lowest. Fowler–Nordheim plots indicate that diamond annealed at 900 °C has the lowest barrier height, which is in good agreement with electron affinities as measured on carbon reconstructed surface. Further increased annealing temperature induces surface graphitization, which causes a threshold voltage increase of field emission.     

A rough set-based hypergraph trust measure parameter selection technique for cloud service selection

Selection of trustworthy cloud services has been a major research challenge in cloud computing, due to the proliferation of numerous cloud service providers (CSPs) along every dimension of computing. This scenario makes it hard for the cloud users to identify an appropriate CSP based on their unique quality of service (QoS) requirements. A generic solution to the problem of cloud service selection can be formulated in terms of trust assessment. However, the accuracy of the trust value depends on the optimality of the service-specific trust measure parameters (TMPs) subset. This paper presents TrustCom—a novel trust assessment framework and rough set-based hypergraph technique (RSHT) for the identification of the optimal TMP subset. Experiments using Cloud Armor and synthetic trust feedback datasets show the prominence of RSHT over the existing feature selection techniques. The performance of RSHT was analyzed using Weka tool and hypergraph-based computational model with respect to the reduct size, time complexity and service ranking.     

Casein based biogenic‐synthesized zinc oxide nanoparticles simultaneously decontaminate heavy metals,dyes, and pathogenic microbes: a rational strategy for wastewater treatment

BACKGROUND

Wastewater management has become a great concern recently due to industrial and domestic discharges containing metals, organic pollutants and pathogenic microbes that contaminate water bodies and also cause waterborne diseases. Although there have been multiple conventional processes for removing contaminants, nanomaterials have recently gained importance for wastewater treatments.

RESULTS

Here, ZnONP_CS with an average size of 10 nm was successfully synthesized by using casein as biogenic reducing and capping agent. Removal of three metals and two dyes was investigated and it was found that nearly 90% was removed. Adsorption isotherm data were best fitted with the Langmuir model, and the maximum adsorption capacity (mg g^?1) was found to be 156.74 for Cd(II), 194.93 for Pd(II), 67.93 for Co(II), 115.47 for methylene blue and 62.19 for congo red. Repeated cycles of regeneration and reuse showed a drop in removal efficiency of 10–13%. Further, nanoparticles also showed efficient photo‐degradation of dyes within 240 min. Moreover, ZnONP_CS demonstrated high antibacterial potential for Escherichia coli in the presence of metals and dyes.

CONCLUSION

Biogenic synthesized ZnONP_CS demonstrated simultaneous removal of metals, dyes as well as pathogenic microbes, and could be used as a cost‐effective and reusable system in various industrial effluent treatments. © 2018 Society of Chemical Industry     

Modulating the performance of carbon nanotube field-effect transistors via Rose Bengal molecular doping

A simple, reliable, and large scale ambient environment doping method for carbon nanotubes is a highly desirable approach for modulating the performance of nanotube based electronics. One of the major challenges is doping carbon nanotubes to simultaneously offer a large shift in threshold voltage and an improved subthreshold swing. In this paper, we report on modulating the performance of carbon nanotube field-effect transistors (CNTFETs) by rationally selecting doping molecules. We demonstrated that Rose Bengal sodium salt (RB-Na) molecular doping can effectively shift the threshold voltage (ΔVth) of CNTFETs up to ～6 V, decrease the subthreshold swing down to 130 mV/decade, and increase the effective field-effect mobility to 5 cm2 V(-1) s(-1). It is also shown that CNTFETs doped with Rose Bengal lactone (RBL) show a smaller variation in ΔVth (～2 V) and subthreshold swing than those doped by RB-Na, which can be attributed to the difference in their molecular structures. The observed right-shift of the threshold voltage is attributed to the positive charge doping of the nanotube conduction channel from Rose Bengal molecules. The resultant lowering of the subthreshold swing is due to the reduced Schottky barrier at the CNT/metal/molecule interface. This room temperature chemical doping approach provides an efficient, simple, and cost-effective method to fabricate highly reliable and high-performance nanotube transistors for future nanotube based electronics.     

Hydrogen peroxide staining to visualize intracellular bacterial infections of seedling root cells

Visualization of bacteria in living plant cells and tissues is often problematic due to lack of stains that pass through living plant cell membranes and selectively stain bacterial cells. In this article, we report the use of 3,3′‐diaminobenzidine tetrachloride (DAB) to stain hydrogen peroxide associated with bacterial invasion of eukaryotic cells. Tissues were counterstained with aniline blue/lactophenol to stain protein in bacterial cells. Using this staining method to visualize intracellular bacterial (Burkholderia gladioli) colonization of seedling roots of switch grass (Panicum virgatum), we compared bacterial free seedling roots and those inoculated with the bacterium. To further assess application of the technique in multiple species of vascular plants, we examined vascular plants for seedling root colonization by naturally occurring seed‐transmitted bacteria. Colonization by bacteria was only observed to occur within epidermal (including root hairs) and cortical cells of root tissues, suggesting that bacteria may not be penetrating deeply into root tissues. DAB/peroxidase with counter stain aniline blue/lactophenol was effective in penetration of root cells to selectively stain bacteria. Furthermore, this stain combination permitted the visualization of the bacterial lysis process. Before any evidence of H₂O₂ staining, intracellular bacteria were seen to stain blue for protein content with aniline blue/lactophenol. After H₂O₂ staining became evident, bacteria were often swollen, without internal staining by aniline blue/lactophenol; this suggests loss of protein content. This staining method was effective for seedling root tissues; however, it was not effective at staining bacteria in shoot tissues due to poor penetration. Microsc. Res. Tech. 77:566–573, 2014. © 2014 Wiley Periodicals, Inc.     

Wind loading effects on a catenary

The effects of wind loads on the static profile and force transmission efficiency of a tether tied to a kite-like aerodynamic body has been theoretically examined. Two important parameters which characterize the behavior of the tether have been obtained. These are the tether weight parameter, which is the ratio of tether weight to the tether tension, and the wind load parameter, which is the ratio of wind load to the tether weight. Results obtained from five different tether models (straight line, catenary, constant velocity, variable velocity and maximum stress) have been compared to determine regions of applicability of these models in terms of the above two parameters.     

Molecular weight distribution of polyethylene terephthalate in homogeneous,continuous-flow-stirred tank reactors

Poly(ethylene terephthalate) (PET) formation in homogeneous, continuous-flow-stirred tank reactors (HCSTRs) operating at steady state has been simulated. The feed to the reactor is assumed to consist of the monomer bis-(hydroxyethyl) terephthalate and monofunctional compound (MF₁) cetyl alcohol. The overall polymerization is assumed to consist of the polycondensation, reaction with monofunctional compounds, redistribution, and cyclization reactions. At a given time, the reaction mass consists of polyester molecules (P_n), polyester molecules with an ending of molecules of monofunctional compound (MF_n), and cyclic polymers (C_n). A mass balance for each of these species in the reactor gives rise to a set of algebraic equations to be solved simultaneously. The MWD calculations show that the redistribution reaction plays a major role and cannot be ignored, This result is in contrast lo the observation for semi-batch reactors, for which redistribution becomes important when the cyclization reaction is included. For the same residence times of semi-batch and HCSTRs, the latter gives considerably lower-number average molecular weight, N_av, and polydispersity index, ρ. However, for the same conversions, the ρ for CSTR is higher. The concentration of the monofurctional compound, [MF₁]₀, in the feed and the reactor temperature both influence ρ, but the effect is small within the range studied.