Photofermentative molecular biohydrogen production by purple-non-sulfur (PNS) bacteria in various modes: The present progress and future perspective

Hydrogen is green fuel for the future, mainly due to its recyclability. Biohydrogen production processes are less energy intensive and environmental friendly in compared to chemical processes. Fermentative biohydrogen production can be broadly classified as: dark and photo fermentation. Two enzymes, nitrogenase and hydrogenase play important role in biohydrogen production. Purple Non-Sulfur bacteria (PNS) are mainly used in photofermentative hydrogen production through which the overall yield can be improved manifolds. The scope and objective of this review paper is to investigate the performance of various light driven photofermentative hydrogen production by PNS bacteria along with several developmental works related to batch, repeated batch, feed batch and continuous operation. However the study of Photobiological process by microalgae or cyanobacteria is outside the scope of this review. Optimization of suitable process parameters such as carbon and nitrogen ratio, illumination intensity, bioreactor configuration, immobilization of active cells in specific continuous mode and inoculum age may lead to higher yield of hydrogen generation.     

Hibiscus sabdariffa (Roselle): A potential source of bast fiber

Roselle is a bast fiber, and its utilization as a textile fiber for the development of textile products is still scanty. A work has been attempted to develop yarn from Roselle. Fibers were extracted from Roselle bark by decortication and degummed in alkaline medium. The degumming process was optimized based on fiber yield and strength. The degummed fibers were then bleached by the hydrogen peroxide bleaching process. Degummed and bleached fibers were characterized by scanning electron microscope, Fourier transform infrared spectroscopy, and X-ray diffraction analysis. Degumming and bleaching results in enhancement of density, fineness, and brightness of Roselle fiber. A marginal decrease in tenacity of the Roselle fiber was observed after bleaching; however, the strength was not affected by degumming. Fibers were converted into fine yarn in the jute spinning system. The yarn properties inferred that the yarn possessed essential properties for the preparation of apparels and home furnishing.     

Exploiting Atomic Control to Show When Atoms Become Molecules

Precision-placed atom qubits in silicon offer a unique means to confine electrons and control their spins with extreme accuracy, which can be leveraged to construct powerful quantum computers. To date atom qubits in silicon have been successfully realized using electrons hosted either on a single phosphorus atom or on a multi-donor quantum dot. Here, a novel molecular regime is explored in which electrons are bound to two donor dots separated by ≈8 nm in a natural silicon substrate. The molecular state, provided by these spatially separated donors, is used to study with exquisite precision the impact of confinement potential on the electronic and spin properties of qubits. Unique spin filling measurements, performed on up to five electrons, confirm how electrons are shared between both sites of the molecule, forming hybridized molecular states. The precise atomic locations of the donor atoms in the silicon lattice are determined by combining the experimental electron spin resonance spectra and the state-of-the-art atomistic modeling of multi-electron wave-functions in presence of realistic electric fields. The donor molecule studied in this work exhibits excellent qubit properties and addresses the impact that the confinement potential has, at the atomic scale, on the desired properties of electron spin qubits.     

Optimization of Quenching Parameters for the Reduction of Titaniferous Magnetite Ore by Lean Grade Coal Using the Taguchi Method and Its Isothermal Kinetic Study

Metallurgical and Materials Transactions B - In the present study, a unique method is adopted to achieve higher reducibility of titaniferous magnetite lump ore (TMO). In this method, TMO is...     

Botnet traffic identification using neural networks

Advancement of information and communication techniques have led to share big amount of information which is increasing day by day through online activities and creating new added value over the internet services. At the same time threats to the security of cyber world has been increased with increasing number of heterogeneous connection points having powerful computational capacity. Internet being used to interact and control such automatic network devices connected to it. But hackers/crackers can exploit this network environment by putting malicious dummy node(s) or machine(s) called Botnet(s) to co-ordinate the attacks on security such as Denial of Service (DoS) or Distributed Denial of Service (DDoS). The proposed method attempts to identify those mallicious Botnet traffic from regular traffic using novel deep learning approaches like Artificial Neural Networks (ANN), Gatted Recurrent Units (GRU), Long or Short Term Memory (LSTM) model. The proposed model demonstrates significant improvement of all previous works. The testing dataset, Bot-IoT dataset is the latest and one of the largest public domain dataset used to justify improvement. Testing shows 99.7% classification accuracy which is precise and better than all previous works done. Results analysis and comparison shows the accuracy and supremacy over the latest work done on this field.

     

DIAL,a system for atmospheric methane measurement over Guwahati: development and results

The article discusses the development and operational details of Differential Absorption LiDAR (DIAL) for the measurement of methane concentration in the semi-urban environment of Gauhati University. The system comprises two specifically selected wavelengths in 3 μm range: one is an absorbing wavelength (λ_on) and the other is non-absorbed (λ_off) by methane molecules. Pulses of 10 ns for the two wavelengths are transmitted alternately for interleaved sampling of differential absorption. The pulse repetition rate is variable between 1 and 20 Hz. The slope and integrated target approaches are adopted to calculate the methane concentration, and observed figures are compared with globally reported values.     

Regression test size reduction using improved precision slices

We propose a technique to select regression test cases that is targeted to reduce the size of test suite by using improved precision slices. For this, we first construct the control flow graph model of an object-oriented program. Subsequently, we identify the infeasible paths and compute the definition-use (def-use) pairs only along the feasible paths. Next, we construct the dependency model using this information. This helps us to ignore the dependencies existing along infeasible paths leading to construction of precise slices. Then, we build the dependency model and construct forward slices on the dependency model to determine the affected nodes and the test cases that cover the affected nodes in the dependency graph model are selected for regression testing. The results obtained from our experimental studies indicate that our approach reduces the regression test suite size on an average by 11.25 % as compared to a related approach, without degrading the fault-revealing effectiveness.     

Assessment of Pb-slag, MSWI bottom ash and boiler and fly ash for using as a fine aggregate in cement mortar

Three types of wastes, metallurgical slag from Pb production (SLG), the sand-sized (0.1-2 mm) fraction of MSWI bottom ash from a grate furnace (SF), and boiler and fly ash from a fluidised bed incinerator (BFA), were characterized and used to replace the fine aggregate during preparation of cement mortar. The chemical and mineralogical behaviour of these wastes along with the reactivities of the wastes with lime and the hydration behaviour of ordinary Portland cement paste with and without these wastes added were evaluated by various chemical and instrumental techniques. The compressive strengths of the cement mortars containing waste as a partial substitution of fine aggregates were also assessed. Finally, leaching studies of the wastes and waste containing cement mortars were conducted. SLG addition does not show any adverse affect during the hydration of cement, or on the compressive strengths behaviours of mortars. Formation of expansive products like ettringite, aluminium hydroxide and H2 gas due to the reaction of some constituents of BFA and SF with alkali creates some cracks in the paste as well as in the cement mortars, which lower the compressive strength of the cement mortars. However, utilization of all materials in cement-based application significantly improves the leaching behaviour of the majority of the toxic elements compared to the waste as such.