Disclination-mediated thermo-optical response in nematic glass sheets

Nematic solids respond strongly to changes in ambient heat or light, significantly differently parallel and perpendicular to the director. This phenomenon is well characterized for uniform director fields, but not for defect textures. We analyze the elastic ground states of a nematic glass in the membrane approximation as a function of temperature for some disclination defects with an eye towards reversibly inducing three-dimensional shapes from flat sheets of material, at the nano-scale all the way to macroscopic objects, including non-developable surfaces. The latter offers a new paradigm to actuation via switchable stretch in thin systems.Comment: Specific results for spiral defects now added. References to Witten, Mahadevan and Ben Amar now added

Leptogenesis and low energy CP phases with two heavy neutrinos

An attractive explanation for non-zero neutrino masses and small matter antimatter asymmetry of the present Universe lies in "leptogenesis". At present the {\it size} of the lepton asymmetry is precisely known, while the {\it sign} is not known yet. In this work we determine the sign of this asymmetry in the framework of two right handed neutrino models by relating the leptogenesis phase(s) with the low energy CP violating phases appearing in the leptonic mixing matrix. It is shown that the knowledge of low energy lepton number violating re-phasing invariants can indeed determine the sign of the present matter antimatter asymmetry of the Universe and hence indirectly probing the light physical neutrinos to be Majorana type.Comment: 26 pages (revtex), 8 eps figures, Typos corrected and one reference is added, Section VI is expanded, Two new figures are added, Journal version, To appear in PR

Description of Drip-Line Nuclei within Relativistic Mean-Field Plus BCS Approach

Recently it has been demonstrated, considering Ni and Ca isotopes as prototypes, that the relativistic mean-field plus BCS (RMF+BCS) approach wherein the single particle continuum corresponding to the RMF is replaced by a set of discrete positive energy states for the calculation of pairing energy provides a good approximation to the full relativistic Hartree-Bogoliubov (RHB) description of the ground state properties of the drip-line neutron rich nuclei. The applicability of RMF+BCS is essentially due to the fact that the main contribution to the pairing correlations is provided by the low-lying resonant states. General validity of this approach is demonstrated by the detailed calculations for the ground state properties of the chains of isotopes of O, Ca, Ni, Zr, Sn and Pb nuclei. The TMA and NL-SH force parameter sets have been used for the effective mean-field Lagrangian. Comprehensive results for the two neutron separation energy, rms radii, single particle pairing gaps and pairing energies etc. are presented. The Ca isotopes are found to exhibit distinct features near the neutron drip line whereby it is found that further addition of neutrons causes a rapid increase in the neutron rms radius with almost no increase in the binding energy, indicating the occurrence of halos. A comparison of these results with the available experimental data and with the recent continuum relativistic Hartree-Bogoliubov (RCHB) calculations amply demonstrates the validity and usefulness of this fast RMF+BCS approach.Comment: 59 pages, 40 figure

Carbon nanotubes — chitosan nanobiocomposite for immunosensor

Carboxylic group functionalized single walled (SW) and multi walled (MW) carbon nanotubes (CNT) have been incorporated into biopolymer matrix of chitosan (CH) to fabricate nanobiocomposite film onto indium– tin–oxide (ITO) coated glass plate for co-immobilization of rabbit-immunoglobulin (r-IgGs) and bovine serum albumin (BSA) to detect ochratoxin-A (OTA). The results of electrochemical studies reveal that presence of both CNT results in increased electro-active surface area of CH leading to enhanced electron transport in these nanobiocomposites. Moreover, in CH–SWCNT and CH–MWCNT nanobiocomposites the availability of NH2/OH group in CH and surface charged CNT also increases loading of the r-IgGs resulting in enhanced electron transport responsible for improved sensing characteristics. Compared to BSA/r-IgGs/CH– MWCNT/ITO immunoelectrode, electrochemical response studies of BSA/r-IgGs/CH–SWCNT/ITO immunoelectrode carried out as a function of OTA concentration exhibits improved linearity as 0.25–6 ng/dL, detection limit as 0.25 ng/dL, response time as 25 s, and sensitivity as 21 μA ng dL−1cm−2 with the regression coefficient as 0.998

A self assembled monolayer based microfluidic sensor for urea detection

Urease (Urs) and glutamate dehydrogenase (GLDH) have been covalently co-immobilized onto a self-assembled monolayer (SAM) comprising of 10-carboxy-1-decanthiol (CDT) via EDC–NHS chemistry deposited onto one of the two patterned gold (Au) electrodes for estimation of urea using poly(dimethylsiloxane) based microfluidic channels (2 cm × 200 μm × 200 μm). The CDT/Au and Urs-GLDH/CDT/Au electrodes have been characterized using Fourier transform infrared (FTIR) spectroscopy, contact angle (CA), atomic force microscopy (AFM) and electrochemical cyclic voltammetry (CV) techniques. The electrochemical response measurement of a Urs-GLDH/CDT/Au bioelectrode obtained as a function of urea concentration using CV yield linearity as 10 to 100 mg dl−1, detection limit as 9 mg dl−1 and high sensitivity as 7.5 μA mM−1 cm−2

Water Requirements For Waterfowl Areas Near the Great Salt Lake Parts V-VI

This report reviews activities on this project since the Progress Report, Part IV, June 1961. The summer of 1961 has been one of the driest on record for Ogden Bay and Howard Slough Refuge. The extreme shortage of irrigation water has resulted in very little flow in the Howard Slough which originates from return flow. The available water from the Weber River for the Ogden Bay Refuge was also the lowest on record. The scarcity of water at these two refuges has resulted in increased salinity. Most of the routine work on the project during the summer was done by Ming Change Tsai, graduate assistant in civil engineering who resided at the Ogden Bay Refuge. Mr. Tsai has been assisted in the care of the salinity lysimiters at Ogden Bay Refuge, and in the salinity surveys at the other refuges by Daya Kaushik, graduate assistant in wildlife resources

RF Energy Harvester-based Wake-up Receiver

Wake-up receivers (WuRxs) can improve the life- time of a wireless sensor network by reducing energy consump- tion from undesirable idle listening. The amplitude level of the incoming RF signal is used by a WuRx to generate an interrupt and wake up the radio of a sleeping sensor node. Existing passive WuRx designs are generally based on RFID tags that incur high cost and complexity. Thus, there is a need for cost-effective and low-complexity WuRxs suited for both long-range and directed wake-ups. In this work, we present a WuRx design using an RF energy harvesting circuit (RFHC). Experimental results show that our RFHC-based WuRx can provide a wake-up range sensitivity around 4 cm/mW at low transmit RF powers ( < 20 mW), which scales to a long wake-up range at high powers. Our design also obtains accurate selective wake-ups. We finally present simulation-based studies for optimizing the design of RFHCs that enhance decoding efficiency with improved rise and fall times

Response of Anabaena species to different nitrogen sources

Nitrogenase activity, ammonia excretion and glutamine synthetase (GS) activity were examined in five strains of Anabaena (A. anomala ARM 314, A. fertilissima ARM 742, A. variabilis ARM 310, A. oryzae ARM 313 and A. oryzae ARM 570) in the presence of 2.5 mM NO3-N (KNO3), 2.5 mM NH– 4-N [(NH4)2SO4] and diatomic nitrogen (N2). Ammonium-N was more inhibitory to nitrogenase activity as compared to NO3-N in all the strains. Maximum GS activity was exhibited in NO3-N medium, irrespective of the cyanobacterial strains studied. Uninduced release of ammonia was observed in all the species, with A. oryzae ARM 313 and Anabaena variabilis ARM 310 exhibiting maximum excretion of 0.25–0.31 and 0.27–1.23 µ moles NH– 4 mg Chl–1 respectively on the 15th day of incubation. The glutamine synthetase activity of A. oryzae ARM 313 was relatively very high as compared to Anabaena variabilis ARM 310. There was no nitrate reductase activity in any of the Anabaena sp. grown on NH3-N or N2-N on the 15th day of incubation

Improving the Performance of Tensor Matrix Vector Multiplication in Quantum Chemistry Codes.

Cumulative reaction probability (CRP) calculations provide a viable computational approach to estimate reaction rate coefficients. However, in order to give meaningful results these calculations should be done in many dimensions (ten to fifteen). This makes CRP codes memory intensive. For this reason, these codes use iterative methods to solve the linear systems, where a good fraction of the execution time is spent on matrix-vector multiplication. In this paper, we discuss the tensor product form of applying the system operator on a vector. This approach shows much better performance and provides huge savings in memory as compared to the explicit sparse representation of the system matrix