The effect of graphene nanosheets on the mechanical properties of polyvinylchloride

In this work, excellent improvement in mechanical properties was observed by incorporating graphene nanofillers in polyvinyl chloride via solution blending. About 63% increase in modulus and 19% increase in ultimate tensile strength were measured at 1.5 wt% nanofiller content while almost no drop in elongation at break was observed. POLYM. COMPOS., 37:1572–1576, 2016. © 2014 Society of Plastics Engineers     

Synthesis of Functionalized Indolizines by Lewis Acid‐Mediated Cyclocondensation of 3‐(Pyridin‐2‐yl)‐propiolates with Enones

Functionalized indolizines were prepared by Lewis acid‐catalyzed cyclizations of 3‐(pyridin‐2‐yl)‐propiolates with enones. This new type of reaction provides a convenient and regioselective approach to ester‐substituted indolizine derivatives which are not readily available by other methods. Based on density function theory (DFT) calculations, a mechanism of the reaction has been suggested.     

Resource refrain quota based routing protocol for delay tolerant network

Wireless Networks - The delay tolerant network Spray and Wait routing protocol minimizes resource consumption by defining the ‘n’ number of message transmission quota. However, with...     

Comparison of different pretreatment methods for hydrogen production using environmental microbial consortia on residual glycerol from biodiesel

The pretreatment of environmental microbial consortia by five methods (acid, base, heat shock, dry heat and desiccation, freezing and thawing) was conducted in order to evaluate their applicability for the selection of hydrogen-producing bacteria capable of using residual glycerol from biodiesel synthesis as substrate. Results showed that substrate degradation rates of consortia pretreated with dry heat and desiccation and heat shock were higher compared with controls during the fermentation using glycerol, with degradation rates as high as 65%. The maximal hydrogen and biomass productions were obtained by dry heat and desiccation: 34.19% mol and 4340 mg/L, respectively. Dry heat and desiccation followed by heat shock are simple pretreatments methods that can be used to improve the biotechnological production of hydrogen. DNA sequencing performed to identify the bacteria strains present in the consortium showed that they belonged to the genus Klebsiella and Pantoea.     

Bioconversion of residual glycerol from biodiesel synthesis into 1,3-propanediol and ethanol by isolated bacteria from environmental consortia

Residual (raw) glycerol originated from biodiesel synthesis is becoming of great environmental and economical concern due to its ever-growing surplus. In the present study, several bacterial strains were isolated and characterized for their ability to convert this raw glycerol into 1,3-propanediol (1,3-PD) and ethanol. The best producers of both 1,3-PD and ethanol were identified by 16S rDNA sequences to be Klebsiella pneumoniae and Pantoea agglomerans strains. Batch bioreactor cultivations under anaerobic and aerobic conditions were carried out in order to access the kinetics of glycerol consumption and product formation. Results showed that one isolated, K. pneumoniae BLh-1, was able to simultaneously produce up to 9.4 g/L of 1,3-PD with yields of 0.41 mol product mol⁻¹ glycerol, and 6.1 g/L of ethanol with yields of 0.14 mol product mol⁻¹ glycerol under anaerobic conditions, showing great potential for bioprocesses.     

Exponential localization of moving end mirror in optomechanics

We discuss the dynamics of moving end mirror of an optomechanical system that consists of a Fabry-Perot cavity loaded with dilute condensate and driven by a single-mode optical field. It is shown that quantum mechanical phenomenon of dynamical localization occurs both in position and momentum space for moving end mirror in the system. The parametric dependencies of dynamical localization are discussed. We also provide a set of parameters which makes this phenomenon experimentally feasible.     

Neural network analysis of switchability of microstrip rectangular patch antenna printed on ferrite material

A switchable microstrip rectangular patch antenna printed on ferrite substrate in the X‐band is presented using general artificial neural network (ANN) analysis. The ferrite substrate offers a number of unique radiation characteristics including switchable and polarized radiations from a microstrip antenna with DC magnetic biasing. In such a case, for particular frequency most of the power is converted into magnetostatic waves and little radiates into air. Subsequently, the antenna behaves as switch off, in the sense that it effectively absent as radiator. Both synthesis and analysis are mainly focused on the switchability of antenna. In this work, radial basis function (RBF) networks are used in ANN models. Synthesis is defined as the forward side and then analysis as the reverse side of the problem. Here, the analysis is considered as a final stage of the design procedure, therefore, the parameters of the analysis ANN network are determined by the data obtained reversing the input–output data of the synthesis network. In the RBF network, the spread value was chosen as 0.01, which gives the best accuracy. RBF is tested with 100 sample frequencies but trained only for particular cutoff 15 sample frequencies. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

Boiling of ammonia/lubricant mixture on a horizontal enhanced tube in a flooded evaporator with inlet vapor quality

In a flooded evaporator of an ammonia vapor-compression refrigeration system, boiling commonly takes place with ammonia mixed with compressor lubricant and subjected to a vapor quality at the inlet of the evaporator. In the present study, flooded boiling tests of ammonia on an enhanced tube under simultaneous influence of a miscible lubricant and inlet quality were conducted. The results suggest that the boiling heat transfer coefficient increases with both saturation temperature and heat flux. The coefficient slightly increases or does not significantly vary with the inlet quality. The coefficient in general is decreased by adding lubricant to the refrigerant, but the coefficient does not necessarily decrease as the lubricant concentration increases. The lubricant effect is generally more significant than the inlet quality effect. A correlation was developed based on the present data for flooded boiling of lubricant/ammonia mixture on an enhanced horizontal tube under the influence of inlet quality.     

Development & Characterization of Green Composites Using Novel 3D Woven Preforms

Green composites are the emerging materials made using natural fibers and environmentally degradable matrix such as green epoxy. Natural fiber composites are the motivation of researchers for low to medium impact applications as well as structural applications like automobiles. In this research work, 3D orthogonal layer to layer (LL) and through the thickness (TT) woven structures with different interlocking patterns, used as preforms in composites are presented. The mechanical properties of preform as well as associated composites are studied on equivalent fiber volume fraction. Jute yarn was woven into four layered 3D woven structures. The use of bridgeable and sustainable fiber, with its prospective use with the biodegradable matrix, is the objective of this work. The focus of this study is to improve mechanical performance by changing weave pattern, so that the resulting composite is robust in design.     

The formation of reverted austenite in 18% Ni 350 grade maraging steel

Austenite reversion was studied in 18% Ni 350 grade maraging steel. The samples were heat treated from room temperature to the austenite phase field and, without holding, they were cooled again to ambient temperature. The reverted austenite which was retained after this heat treatment was examined using a scanning transmission electron microscope equipped with an energy dispersive spectroscopic system. Two morphologies of the austenite were observed. The first forms at the martensite lath boundaries and the other nucleates inside the martensite laths in the form of Widmanstatten plates. These Widmanstatten plates mostly appear as coupled twins. The coupled twins have a distinct midrib which was found parallel to (1 1 1) and (1 1 0) planes. The latter morphology of austenite appeared only after the formation of Ni3Ti precipitates. Growth of Fe2Mo precipitates was not observed in this heat-treatment cycle. Both Nishyama–Wassermann and Kurdjumo–Sachs orientation relationships were found between the austenite and martensite phases. On the basis of these results, it can be suggested that intra-lath-reverted austenite is formed on or by the local dissolution of Ni3Ti precipitates. © 1998 Kluwer Academic Publishers