Theoretical study of the effect of liquid desiccant mass flow rate on the performance of a cross flow parallel-plate liquid desiccant-air dehumidifier

A computer simulation using MATLAB is investigated to predict the distribution of air stream parameters (humidity ratio and temperature) as well as desiccant parameters (temperature and concentration) inside the parallel plate absorber. The present absorber consists of fourteen parallel plates with a surface area per unit volume ratio of 80 m²/m³. Calcium chloride as a liquid desiccant flows through the top of the plates to the bottom while the air flows through the gap between the plates making it a cross flow configuration. The model results show the effect of desiccant mass flow rate on the performance of the dehumidifier (moisture removal and dehumidifier effectiveness). Performance comparisons between present cross-flow dehumidifier and another experimental cross-flow dehumidifier in the literature are carried out. The simulation is expected to help in optimizing of a cross flow dehumidifier.     

Theory of hyperfine interactions associated with the negative muon in lanthanum copper oxide high Tc system

The reaction mechanism of excitation and de-excitation of the high-spin isomers ¹⁸⁰Hf (J=8^-) and ¹⁸⁰Ta (J=9^-) in inelastic gamma-quanta scattering was investigated. An anomalously large integral cross section and isomeric ratio for ¹⁸⁰Ta in comparison to ¹⁸⁰Hf were obtained. Level properties influencing these relations are discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Preparation and structure of high-chlorinated bornane derivatives for the quantification of toxaphene residues in environmental samples

Summary The HRGC-determination of Taxophene® residues in the presence of other chlorinated hydrocarbons with similar retention times is often difficult. This problem can satisfactorily be overcome by using purely isolated high-chlorinated bornane derivatives (7–17) as standard. The method is highly selective for measuring toxaphene in complex environmental matrices, such as fish, and can also be used for evaluating the changes in the relative distribution that may have resulted from bioaccumulation and environmental transformation.Dedicated to Professor Dr. Wilhelm Fresenius on the occasion of his 80th birthday     

The detection of aluminium complexes in forest soil solutions and beech xylem saps

Summary An ion-pair chromatographic method in which aluminium is quantitatively determined via derivatization with 8-hydroxyquinoline-5-sulphonic acid was evaluated for its utility as a method for speciating Al in soil solutions and xylem saps. The results show that aluminium fluoride and several five- or six-membered chelate complexes are stable enough to be analyzed chromatographically.     

The walk partition and colorations of a graph

We study the partitions of a graph G with vertices labeled 1,2,…,n. A matrix notation for partitions is devised which reflects a partial order among partitions and provides a matrix characterization (in terms of the adjacency matrix A of G) of a coloration or equitable partition. An especially useful partition is one based on the number of walks issuing from each vertex. This is not generally a coloration (sufficient conditions are given) but nevertheless plays a special role relative to colorations. The spectrum of G, Sp(G), has a “main part”, the set of eigenvalues with an eigenvector not orthogonal to e (the column of 1s). We disprove a conjecture of Harary and Schwenk about the main part of the spectrum and prove an alternate characterization. The walk partition appears here and also in a relation between the main parts of the spectra of G and ?, its complement.     

Impact of Redhat IPv6 router on heterogeneous host connections

Internet's popularity has been expanding on dramatic pace and the number of people getting connected to it multiplies regularly. With this high demand, the current Internet Protocol (IPv4) has reached its limits. The next generation Internet Protocol version6 (IPv6) has been incorporated into various operating systems. The motivation behind this work is how well IPv6 co‐operates with various operating systems. The performance of the IP stack, together with the behaviour of the OS greatly affects the efficiency of network applications built on top of it. The acceptance of IPv6 implementations on various operating systems heavily relies on the end‐user performance. In this paper, we propose to analyse these various IPv6 implementations for its host and router‐level supports. In this paper, we investigate the impact of Redhat‐based IPv6 router on IPv6 stacks of three different operating systems namely, Windows2003, Redhat Linux 9.0 (Redhat9.0) and FreeBSD4.9. Copyright © 2006 John Wiley & Sons, Ltd.     

Self-excited brillouin–erbium fiber laser for DWDM applications

The operation of the self-excited Brillouin/erbium fiber laser (BEFL) is experimentally demonstrated. It uses a forward pumped erbium-doped fiber (EDF) as a gain medium to generate a Brillouin-pump (BP) and amplify the Stokes frequency signals generated in a single-mode fiber (SMF). The operating wavelength varies with changes of coupling ratio of the looping arm. The optimum BEFL operation is obtained with a center wavelength at 1567.5 nm by looping back 20% of BEFL output into the other end of the SMF. The BEFL output power and number of lines increases gradually as 980-nm pump power increases. At the maximum 980-nm pump power of 118 mW, a stable and strong BEFL comb of up to 16 lines with 11 GHz spacing is demonstrated. The self-excited BEFL has the potential to be used in the future dense wavelength division multiplexing (DWDM) communication system.     

Effects of output coupler reflectivity on the performance of a linear cavity Brillouin/erbium fiber laser

The effect of output coupler reflectivity (or output coupling ratio) on the performance of a linear cavity Brillouin/erbium fiber laser (BEFL) is demonstrated. The operating wavelength, output laser power and number of channels vary with changes in the coupling ratio in the linear cavity system. The optimum BEFL operation is obtained with an output coupling of 40%, i.e., 60% of the laser power is allowed to oscillate in the cavity. A stable laser comb consisting of up to 40 channels with line spacings of approximately 0.09 nm are obtained at the Brillouin pump and 980 nm pump with powers of 2.5 mW and 100 mW, respectively. The linear cavity BEFL has the potential to be used in inexpensive wavelength division multiplexing system.      

Synthesis of new boswellic acid derivatives as potential antiproliferative agents

Abstract

In the current investigation, a series of heterocyclic derivatives of boswellic acids were prepared along with new monomers of 3-O-acetyl-11-keto-β-boswellic acid (AKBA, 1) 11-keto-β-boswellic acid (KBA, 2) and several new bis-AKBA and KBA homodimers and AKBA-KBA heterodimers. The effects of these compounds on the proliferation of different human cancer cell lines, viz., FaDu (pharynx carcinoma), A2780 (ovarian carcinoma), HT29 (colon adenocarcinoma), and A375 (malignant melanoma), have been evaluated. Thus, KBA homodimer 21 effectively inhibited the growth of FaDu, A2780, HT29, and A375 cells with EC₅₀ values below 9?μM. In addition, compounds 7, 8, 11, 12, 15, 16, and 17 also exhibited cytotoxic effects for A2780, HT29, and A375 cancer cells. In particular, the pyrazine analog 8 was highly cytotoxic for A375 cancer cells with an EC₅₀ value of 2.1?μM.