Effect of amphiphilic compatibilizers on the filler dispersion and properties of polyethylene—thermally reduced graphene nanocomposites

Compatibilizers of different chemical structures and specifications were used to enhance the filler exfoliation in nanocomposites of polyethylene and thermally reduced graphene prepared by melt mixing route. The mechanical performance of the compatibilized nanocomposites was observed to be better than PE/G nanocomposites due to enhanced extent of filler exfoliation and distribution. Highest increase of 45% in tensile modulus and 13% in peak stress was observed in the composites. Overall, from the mechanical, rheological, thermal, and calorimetric properties, the compatibilizers with best performance were ethylene acrylic acid (EAA) copolymer and chlorinated polyethylene (CPE25). Furthermore, the extent of filler exfoliation was observed to increase with increasing EAA content thus confirming positive interactions between EAA and thermally reduced graphene, though no specific chemical interactions could be detected. The composite properties were observed to reach maximum around 7.5 wt % EAA content, followed by reduced performance due to extensive matrix plasticization. The observed behaviors were a result of interplay of opposing factors like filler exfoliation due to compatibilizer addition and matrix plasticization due to its lower molecular weight, thus the observed optimum comaptibilizer amount was specific to the compatibilizer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42484.     

Parallel query execution over encrypted data in database-as-a-service (DaaS)

The Journal of Supercomputing - The main challenge in database-as-a-service is the security and privacy of data because service providers are not usually considered as trustworthy. So, the data...     

SPICE compatible analytical electron mobility model for biaxial strained-Si-MOSFETs

This paper describes an analytical model for bulk electron mobility in strained-Si layers as a function of strain.Phonon scattering,columbic scattering and surface roughness scattering are included to analyze the full mobility model.Analytical explicit calculations of all of the parameters to accurately estimate the electron mobility have been made.The results predict an increase in the electron mobility with the application of biaxial strain as also predicted from the basic theory of strain physics of metal oxide semiconductor(MOS) devices.The results have also been compared with numerically reported results and show good agreement.     

Architecture and Physical Implementation of a Third Generation 65 nm, 16 Core, 32 Thread Chip-Multithreading SPARC Processor

This third-generation Chip-Multithreading (CMT) SPARC processor consists of 16 cores with shared memory architecture and supports a total of 32 main threads plus 32 scout threads. It is targeted for high-performance servers, and is optimized for both single- and multi-threaded applications. The 396 mm² chip is fabricated in an 11 metal layer 65-nm CMOS process and operates at a nominal frequency of 2.3 GHz, consuming a maximum power of 250 W at 1.2 V. This paper provides an overview of the architectural highlights and describes the physical implementation challenges and solutions including circuit innovations in memory arrays, register files, and floating-point hardware that boost the performance and circuit robustness with low area overhead.     

Transient solutions of some multiserver queueing systems with finite spaces

The purpose of this paper is to provide explicit transient solutions for the multiserver queueing system Geom ( n )/ Geom ( n )/ c / N + c . The method proposed here can also be used for obtaining transient solutions of Markov chains having the transition matrix of Hesselberg type. To support this, we also consider a more complex model such as GI / M / c / N + c . In our analysis, we use eigenvalues and generalized eigenvectors of transition probability matrices. Since we use the Jordan canonical form from linear algebra, the method is good even if the eigenvalues are repeated. Numerical procedures for computations involved in various examples are also provided.     

On a class of branching problems in broadcasting and distribution

We introduce the following network optimization problem: given a directed graph with a cost function on the arcs, demands at the nodes, and a single source s, find the minimum cost connected subgraph from s such that its total demand is no less than lower bound D. We describe applications of this problem to disaster relief and media broadcasting, and show that it generalizes several well-known models including the knapsack problem, the partially ordered knapsack problem, the minimum branching problem, and certain scheduling problems. We prove that our problem is strongly NP-complete and give an integer programming formulation. We also provide five heuristic approaches, illustrate them with a numerical example, and provide a computational study on both small and large sized, randomly generated problems. The heuristics run efficiently on the tested problems and provide solutions that, on average, are fairly close to optimal.     

Minor components ofLesquerella fendleri seed oil

Routine analysis of fatty ester fractions ofLesquerella fendleri oil suggested the presence of epoxy compounds and other minor components. By a combination of open silica column and high performance liquid chromatography (HPLC) fractionations of the methyl esters prepared from the oil, these constitutents were isolated and then characterized by thin-layer chromatography-mass spectrometry (GC-MS—electron ionization, EI, and chemical ionization, CI) and nuclear magnetic resonance (NMR—¹H and¹³C). Three epoxy acids, 15,16-epoxy-9,12-octadecadienoic, 9,10-epoxy-12-octadecenoic and 9,10-epoxy-octadecanoic, were found. Hydroxy acids present included a C-22 homologue of lesquerolic acid (16-hydroxy-12-docosenoic acid) and 14,15-dihydroxy-tricosanoic acid. Other minor ocmponents included four sterols, brassicasterol, campesterol, β-sitosterol and stigmasterol, and a series of saturated and unsaturated fatty acids up to C30. Visiting postdoctoral scientist sponsored by the government of India.     

Leak Detection in Pipes by Frequency Response Method

The frequency response method is used to determine the location and rate of leakage in open loop piping systems. A steady-oscillatory flow, produced by the periodic opening and closing of a valve, is analyzed in the frequency domain by using the transfer matrix method, and a frequency response diagram at the valve is developed. For a system with leaks, this diagram has additional resonant pressure amplitude peaks (herein referred to as the secondary pressure amplitude peaks) that are lower than the resonant pressure amplitude peaks (herein called primary amplitude peaks) for the system with no leaks. Several piping systems are successfully analyzed for all practical values of the friction factor to detect and locate individual leaks of up to 0.5% of the mean discharge. The method, requiring the measurement of pressure and discharge fluctuations at only one location, has the potential to detect leaks in real-life pipe systems conveying different types of fluids, such as water, petroleum, and so on.