On the polar decomposition of right linear operators in quaternionic Hilbert spaces

In this article we prove the existence of the polar decomposition for densely defined closed right linear operators in quaternionic Hilbert spaces: If $T$ is a densely defined closed right linear operator in a quaternionic Hilbert space $H$, then there exists a partial isometry $U_{0}$ such that $T = U_{0}|T|$. In fact $U_{0}$ is unique if $N(U_{0}) = N(T)$. In particular, if $H$ is separable and $U$ is a partial isometry with $T = U|T|$, then we prove that $U = U_{0}$ if and only if either $N(T) = \{0\}$ or $R(T)^{\bot} = \{0\}$.Comment: 17 page

Staudinger/aza-Wittig Reaction to Access Nβ-Protected Amino Alkyl Isothiocyanates

A unified approach to access Nβ-protected amino alkyl isothiocyanates using Nβ-protected amino alkyl azides through a general strategy of Staudinger/aza-Wittig reaction is described. The type of protocol used to access isothiocyanates depends on the availability of precursors and also, especially in the amino acid chemistry, on the behavior of other labile groups towards the reagents used in the protocols; fortunately, we were not concerned about both these factors as precursor-azides were prepared easily by standard protocols, and the present protocol can pave the way for accessing title compounds without affecting Boc, Cbz and Fmoc protecting groups, and benzyl and tertiary butyl groups in the side chains. The present strategy eliminates the need for the use of amines to obtain title compounds and thus, this method is step-economical; additional advantages include retention of chirality, convenient handling and easy purification. A few hitherto unreported compounds were also prepared, and all final compounds were completely characterized by IR, mass, optical rotation, and 1H and 13C NMR studies

Low-Temperature Permittivity of Insulating Perovskite Manganites

Measurements of the low-frequency (f<=100 kHz) permittivity and conductivity at T<= 150 K are reported for La(1-x)Ca(x)MnO(3) (0<=x<=1) and Ca(1-y)Sr(y)MnO(3) (0<=y<=0.75) having antiferromagnetic, insulating ground states covering a broad range of Mn valencies from Mn(3+) to Mn(4+). Static dielectric constants are determined from the low-T limiting behavior. With increasing T, relaxation peaks associated with charge-carrier hopping are observed in the real part of the permittivities and analyzed to determine dopant binding energies. The data are consistent with a simple model of hydrogenic impurity levels and imply effective masses m*/m_e~3 for the Mn(4+) compounds. Particularly interesting is a large dielectric constant (~100) associated with the C-type antiferromagnetic state near the composition La(0.2)Ca(0.8)MnO(3).Comment: 6 pages, 8 figures, PRB in pres

Lab Scale Fixed-Bed Reactor for Operando X-Ray Absorption Spectroscopy for Structure Activity Studies of Supported Metal Oxide Catalysts

Lab scale fixed-bed reactor is applied for operando transmission X-ray absorption spectroscopy (XAS) for structure-activity studies of supported metal oxide catalysts under real reaction conditions. This setup includes many properties of an optimal fixed-bed reactor for operando transmission XAS studies. For instance, it is usable in a wide range of temperature (up to 1,000°C), pressure and space velocity. Besides, this operando setup can be used for transmission XAS measurements in a wide edge energy range. The potential of this reactor for operando transmission XAS is demonstrated by, as examples, the three-way catalytic performance of Pd/Al2O3/CeZrO2 and Rh/Al2O

Poly-alphabetic Symmetric Key Algorithm Using Randomized Prime Numbers

Abstract- Cryptography is an art and science. It is a playing major role in information and security division. The main aim of the cryptography is protecting the data from unauthorized users or hackers. “Cryptography is subject contains two parts one is encryption and another one decryption. Encryption is a process converting the plain text to cipher text using some keys. Decryption is a process of converting the cipher text to plain text using the keys”. There are several algorithms in cryptography to encode and decode the data based on the key. This paper discusses types of cryptography and different keys in cryptography. The paper can give brief description about symmetric key algorithms and we are proposing new algorithm in symmetric key cryptography. The proposed algorithm contains two levels of Exclusive OR (XOR) operation. This algorithm is useful in transmission of messages and data between one user and another. situation the both parties use the additional key, which is common to both parties. First they will do the encryption or decryption with the same key, and again do the encryption or decryption with their own key. Example for public key algorithms is RSA, Diffie Hellman key exchange protocol. B. Symmetric key algorithms Symmetric algorithms is also called as secrete key algorithms. In secrete key algorithms both parties (Sender, Receiver) will use the same key to encrypt or decrypt the data. Example for symmetric key algorithms is DES, AES, Triple DES, and Blowfish

Heat Conduction and Magnetic Phase Behavior in Electron-Doped Ca_{1-x} La_x MnO_3(0 <= x <= 0.2)

Measurements of thermal conductivity (kappa) vs temperature are reported for a series of Ca_{1-x} La_x MnO_3(0 <= x <= 0.2) specimens. For the undoped (x=0), G-type antiferromagnetic compound a large enhancement of kappa below the Neel temperature (T_N ~ 125 K) indicates a strong coupling of heat-carrying phonons to the spin system. This enhancement exhibits a nonmonotonic behavior with increasing x and correlates remarkably well with the small ferromagnetic component of the magnetization reported previously [Neumeier and Cohn, Phys. Rev. B 61 14319 (2000).] Magnetoelastic polaron formation appears to underly the behavior of kappa and the magnetization at x <= 0.02.Comment: submitted to PRB; 4 pp., 4 Fig.'s, RevTex

Simulation of heat transport in low-dimensional oscillator lattices

The study of heat transport in low-dimensional oscillator lattices presents a formidable challenge. Theoretical efforts have been made trying to reveal the underlying mechanism of diversified heat transport behaviors. In lack of a unified rigorous treatment, approximate theories often may embody controversial predictions. It is therefore of ultimate importance that one can rely on numerical simulations in the investigation of heat transfer processes in low-dimensional lattices. The simulation of heat transport using the non-equilibrium heat bath method and the Green-Kubo method will be introduced. It is found that one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) momentum-conserving nonlinear lattices display power-law divergent, logarithmic divergent and constant thermal conductivities, respectively. Next, a novel diffusion method is also introduced. The heat diffusion theory connects the energy diffusion and heat conduction in a straightforward manner. This enables one to use the diffusion method to investigate the objective of heat transport. In addition, it contains fundamental information about the heat transport process which cannot readily be gathered otherwise.Comment: Article published in: Thermal transport in low dimensions: From statistical physics to nanoscale heat transfer, S. Lepri, ed. Lecture Notes in Physics, vol. 921, pp. 239 - 274, Springer-Verlag, Berlin, Heidelberg, New York (2016

Participatory fish production in Dhalai district of Tripura, northeast India

Composite culture at a species composition of 40% catla (Catla catla), 30% rohu (Labeo rohita), 20% mrigal (Cirrhinus mrigala) and 10% grass carp (Ctenopharyngodon idella) in a combined stocking density of 5000 fingerlings ha-1 was demonstrated in participatory mode in Dhalai District of Tripura, NE India for three consecutive years (2009-10, 2010-11 and 2011-12) with an aim to see the production performance and economic benefit of the system over traditional culture system. Growth of the fish was higher in composite culture than traditional farming in all the locations. Grass carp dominated the size followed by catla, rohu and mrigal in all the ponds. Total production of fish in composite culture (934-1545 kg ha-1) was higher than traditional farming (322-335 kg ha-1). Gross profit in composite culture (Rs. 2,23,192 ha-1) was higher than traditional farming (Rs. 58,386 ha-1). Similarly, net profit in composite culture (Rs. 1,12,383 ha-1) was higher than traditional method (Rs. 15,719 ha-1). Benefit-cost ratio was 1.93 in composite culture and 1.36 in traditional culture. Overall, composite culture of fish was found as a viable option for enhancing fish production in Dhalai district of Tripura by 192-360%