A unified set of proposals for control and design of high speed data networks

In this paper we articulate our philosophy and approach to the design and control of high speed data networks. The object is to put into perspective and to explain the coordination of various isolated pieces of detailed technical analyses that have been reported in several recent papers. In the process we summarize what we have learnt in our recent work and, also, we give indications of the direction of our future work. Our scheme integrates feedback and open loop control. The feedback control is exercised by sliding windows; access controllers regulate bursty sources. All our design proposals are rooted in asymptotic analyses; the justification for asymptotics comes from the largeness of the parameters, such as propagation delay, speed, window size, buffer size, and the number of virtual circuits. This analysis makes a strong case for operating in a specific moderate usage regime, and adaptive dynamic windowing algorithms are given that make this happen; moreover, when in this regime, buffers may be sized aggressively small without jeopardizing performance and the simplicity of the retransmission protocol. The topics in the paper are: model of communication, results on the steady-state behavior of the basic model, access control, small buffers and retransmission protocols, dynamic adaptive windows, bursty sources, and contrast with previous work.I. Mitrani's work was done while AT&T Bell Laboratories.     

Donor properties of some flexidentate hydroxyimino-β-diketones in their rhodium(III) complexes

Summary A series of rhodium(III) complexes of certain hydroxyimino--diketones were synthesised and their structures assigned on the basis of elemental analyses and i.r. and¹H n.m.r. spectral studies, The complexes exhibit coordination through carbonyl oxygen and nitrogen of the hydroxy-imino groups in the ligands.¹H and¹³C n.m.r. studies show that the ligands exist in the isonitroso form in CDCl₃.     

Non-isothermal studies of adduct molecules of metallic halides with oxo-compounds in solid state. V

Non-isothermal studies of some adduct molecules of metallic halides with tetrahydropyran as the type MX₂(THP)_y in solid state, were carried out with a Derivatograph, where M  Mn(II), Co(II), Ni(II), Cu(II) or Cd(II), XCl^- or Br^-, THPtetrahydropyran and y0.1–1. These adduct molecules lost tetrahydropyran in single or multiple steps upon heating. Thermally stable intermediate products were isolated and characterised by elemental analysis and IR spectral measurement. The activation energy for each step of decomposition of the adduct was evaluated from the analysis of TG, DTG and DTA curves of the respective derivatogram. The enthalpy change was evaluated from the DTA peak area and the order of reaction was found to be unity, for each step of decomposition. Thermal parameters for the above adducts were compared with the adducts of other oxocompounds like dioxan, tetrahydrofuran, ethylene glycol dimethyl ether and diisopropyl ether.     

Extraction-spectrophotometric determination of uranium(VI) with PAR and N-octylacetamide

A new and simple method for selective spectrophotometric determination of uranium(VI) with 4-(2-pyridylazo)resorcinol (PAR) and N-octylacetamide into benzene over pH 7.0–9.0 is described. The molar absorptivity of the complex with 9 different amides is in the range of (0.40–3.2)·10⁴ 1·mol^–1·cm^–1 at the absorption maximum. Out of these, the most sensitive compound N-octylacetamide (OAA) was chosen for detailed studies in the present investigation. The detection limit of the method is 0.008 g U·ml^–1. The system obeys Beer's law in the range of 0–5 g U·ml^–1. The method is free from interferences of most of the common metal ions except vanadium(V) and copper(II), which are masked by proper masking agents. The composition of the complex is determined by curve-fitting method. The method has been applied for the recovery of the metal from rock samples and synthetic mixtures.     

Synthesis of 2-Azobenzo[b]thiophene Derivatives and Their Application on Nylon Fibre

A series of novel monoazo disperse dyes derived from the coupling of diazotized 2-aminobenzo[b]thiophene derivatives with N-arylmaleimides is described. The monoazo disperse dyes applied to nylon fabric and their dyeing performance has been assessed. These dyes have been found to give light yellow to reddish pink color shades with very good depth and levelness on nylon fabric. The dyed fabric shows moderate light fastness and excellent washing, rubbing, perspiration, and sublimation fastness. The percentage dyebath exhaustion on nylon fabric has been found to be good and acceptable.     

Tetrabutylammonium tribromide (TBATB)-MeOH: An efficient chemoselective reagent for the cleavage of tert-butyldimethylsilyl (TBDMS) ethers

TBDMS, THP, and DMT ethers are efficiently deprotected with tetrabutylammonium tribromide in methanol. The apparent order of stability of different protecting group is phenolic TBDMS > 1 degrees OTBDPS > 2 degrees OTBDMS > 2 degrees OTHP > 1 degrees OTHP > 1 degrees OTBDMS > 1 degrees ODMT. TBDMS ether has been cleaved selectively in the presence of isopropylidine, Bn, Ac, Bz, THP, and TBDPS groups. This method is high yielding, fast, clean, safe, cost-effective, and therefore most suitable for practical organic synthesis.     

Small-angle x-ray investigation of a densely packed micelle system in agave hybrid

Small-angle x-ray scattering methods were applied to calculate macromolecular parameters like specific inner surface (O/V), length of coherence (l_c), and the percentage of air present in agave hybrid, treating it as a densely packed colloidal system belonging to a general micelle system. The parameters were equal to O/V = 8.50 × 10^?6 Å^?1, l_c = 150 Å, and the percentage of air = 0.03. The Kratky camera with latest design was used for the experimental measurement. Because the sample agave ybrid is a natural fiber and a highly oriented system that is celluosic in character, the theories of Kratky and Porod have been used to evaluate these parameters.