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High level behavioral modeling is widely used in lieu of low level transistor models to ascertain the behavior of input/output (IO) drivers and receivers. The input output buffer information specification (IBIS) is one of the most widely used methodologies to model IO drivers as it satisfies the basic requirements of a behavioral model such as IP protection, simple structure, fast simulation time, and reasonable accuracy. As driver technology gets increasingly complicated and rise time of input signal gets increasingly smaller, important considerations such as simultaneous switching noise (SSN) becomes a major consideration when simulating multiple IO drivers in the integrated circuit. Unfortunately, IBIS falls short of becoming a complete IO behavioral model when simulating for SSN. This paper addresses the problem by assessing what is missing in IBIS. A method is presented for compensating for the missing information by complimenting the IBIS model with a black box that is simulator independent, without compromising with the speed that IBIS enjoys over the transistor models.

The petrography of lignitic, subbituminous and bituminous inertinitic coals (i.e. coals containing > 30 modal percent inertinite on a mineral-matter-free basis) derived from limnic and paralic facies in the Upper Silesian coal basin of Poland was investigated. Paralic coals were observed to contain small amounts of telinite and abundant pyrofusinite compared to limnic coals. The ratio of oxysemifusinite and oxyfusinite to pyrosemifusinite and pyrofusinite is lower in paralic coals as compared to limnic coals. The statistical analysis of the reflectances of the inertinite group macerals and of vitrinite shows that paralic coals are more heterogeneous than limnic coals. This greater degree of heterogeneity may explain the differences in reactivity among coals that otherwise have the same rank and elemental and petrographic composition.

Medium-rank inertinite-rich coal samples were collected for study from limnic and paralic facies in the Upper Silesian coal basin of Poland. The microlithotypes seem to control the content of the mosaic textures. It also appears that carbominerites favor the formation of pyrolytic carbons. The coke obtained from poorly pyrofusinitized, homogeneous, limnic coal has higher mechanical strength with larger and thicker cell walls, and is less porous than those derived from highly pyrofusinitized, heterogenous paralic ones. The microstructure of the cokes appears to be controlled by different amounts of fibers and coarse mosaics.

Presents the results estimation of wind speeds over oceanic regions based on the analysis of SUNGLINT signatures observed in INSAT-VHRR visible band images. Wind speed estimates are derived using the observed intensity gradients across the glinted area. Which is observed to cover a very large region. Sometimes approaching a few million sq. kms. Analysis of sunglint signatures recorded simultaneously on VHRRs onboard INSAT-1D and INSAT-2A satellites, located 10/spl deg/ apart on the equator on Feb. 17, 1993 at 0600 GMT is presented and discussed. The estimated wind speed values over the glint region are compared with the monthly mean wind speed climatological values over the region of interest at well at with near-simultaneous wind speed and wave height measurements from radar altimeter onboard ERS-1. The results indicate the good possibility of estimation of wind speeds using sunglint signatures observed in geostationary VHRR images with an estimated accuracy of /spl plusmn/1.5 m/sec. >

This paper describes a method for the rapid isolation of phycobilisomes using a cationic detergent, CTAB (cetyltrimethylammonium bromide). The method has distinct advantages over those currently in use in that (i) release of intact phycobilisomes from cells in the presence of CTAB occurs in 40 s (as compared to 40–60 min of incubation required with Triton X-100), thereby reducing the chances of proteolysis of the component phycobiliproteins; and (ii) these phycobilisome preparations have reduced chlorophyll contamination in the initial stages. In addition this method also helps retain the structural and functional properties, as evidenced by spectroscopy and sodium dodecyl sulfate-polyacrylamide gel analysis.

An investigation has been conducted into the effects of ignoring various scalar second-order correlations on the prediction of chemically reacting, turbulent flowfields. A new second-order closure code for such flowfields, METREC, has been employed to investigate the effects of correlations in species ( α′β′ ), temperature ( T′T′ ), and species and temperature ( T′α′ ). The effects of these correlations were evaluated employing a “second-order approximation” within the METREC code. It is shown that the neglect of these correlations can profoundly affect the resulting flowfield predictions, especially the computation of flame velocities of turbulent mixtures. In turbulent diffusion flames, the dominant correlation in the chemical source term is the mixedness correlation, α′β′ / α β , which can lead to orders of magnitude reduction in the effective reaction rate.

An investigation has been conducted into the effects of ignoring various scalar second-order correlations on the prediction of chemically reacting, turbulent flowfields. A new second-order closure code for such flowfields, METREC, has been employed to investigate the effects of correlations in species ( α ′ β ′ ¯ ) , temperature ( T ′ T ′ ¯ ) , and species and temperature ( T ′ α ′ ¯ ) . The effects of these correlations were evaluated employing a “second-order approximation” within the METREC code. It is shown that the neglect of these correlations can profoundly affect the resulting flowfield predictions, especially the computation of flame velocities of turbulent mixtures. In turbulent diffusion flames, the dominant correlation in the chemical source term is the mixedness correlation, α ′ β ′ ¯ / α ¯ β ¯ which can lead to orders of magnitude reduction in the effective reaction rate.

Progress made toward modeling two-phase flow in a swirl combustor is outlined. Work has concentrated on developing a phenomenological model to guide proper scaling. This simple model will also serve as a skeleton for the more detailed computer model which will be developed in the next few months. Scaling relations indicate that the PERC design for the first stage gasifier-combustor for the CDIF should have a higher carbon conversion efficiency, but is likely to have a slightly higher ash carry-over than that which occurs in PERC's laboratory scale model. If desired, the carry-over may be reduced by decreasing the fraction of small coal particles. It also appears that the total pressure drop will be somewhat larger.

A phenomenological model of flow in a cyclone coal combustor-gasifier is presented. The model predicts how four performance parameters which measure the carbon conversion efficiency, ash separation, pressure drop, and heat losses depend on such design variables as chamber pressure, size and shape, flow rates, and stoichiometry, along with coal particle size and composition. Correct prediction of the performance parameters requires accurate analysis of the coal particle combustion, particle mechanics and fluid mechanics, all of which are coupled in this confined vortex flow. The model is based on assimilating simple approximations to the most important mechanisms governing flow and combustion in the chamber and thus necessarily involves empirical coefficients. Model verification by comparison with laboratory results from Pittsburgh Energy Research Center shows reasonable agreement, but due to the empiricism required in the model further tests are warranted. Model derivation and sensitivity analysis pinpoint the phenomena which are most critical to the performance of a cyclone combustor. Methods for reducing the empirical requirement of the model are discussed and recommendations made for model improvement.

During the past two months work has been concentrated on two tasks in the program to model two-phase flow in a swirl combustor. First, a computer program has been written and debugged to implement the phenomenological model outlined in the December 1976 progress report. Second, a more detailed analysis of the cylindrical wall layer has been initiated to reduce the empiricism required to model this critical region. Carrying out verification tests on the model using experimental test results from Pittsburg Energy Research Center during the next few months is anticipated.

1. 1. As in other bacteria, SO42− in Nitrobacter agilis is first activated by ATP, before it is reduced. Both 35S-labelled adenosine 5′-phosphosulphate ([35S]APS) and 35S-labelled 3′-phosphoadenosine 5′-phosphosulfate ([35S]PAPS) are produced from 35SO42− and ATP in cell-free extracts of this bacterium. The enzymes catalysing these reactions are found in the supernatant fractions left after centrifuging cell extracts at 144 000 × g for 4 h . 2. 2. In addition to the 35S radioassay technique, the bioluminescence method of the firely Photinus pyralis (luciferin-luciferase) was used to follow ATP production from APS and PP1 during the purification of the enzyme. 3. 3. ATP-sulphurylase ATP- sulphate adenyltransferase, EC 2.7.7.4), which catalyzes the formation of APS, was purified about 820-fold by DEAE-cellulose, DEAE-Sephadex and Sephadex G-200 column chromatography, followed by the sucrose density gradient. A starch-gel electrophoresis of the purified enzyme produced a single protein band. 4. 4. K m values for the purified enzyme are as follows: ATP, 1.4 · 10 −3 M ; APS, 2.5 · 10 −5 M ; PP i , 1.2 · 10 −4 ; MgCl 2 3.5 · 10 −4 M . 5. 5. The molecular weight of the enzyme is about 700 000 and the sedimentation coefficient is 12.8 S. The pH optimum is 7.4. 6. 6. The enzyme was inhibited by group IV anions. The following thiol reagents stimulated activity: GSH, l -cysteine, β-mercaptoethanol and Cleland's reagent (dithiothreitol). p- Chloromercuribenzoate was a strong inhibitor and this effect was reversed by thiol compounds.

This chapter describes some microscopical approaches for analyzing the structure of endomycorrhizal infections, identifying modifications in protein expression (enzyme activities) and localizing specific molecules at both the tissue and cellular level. Techniques are chosen to illustrate how they can not only increase the understanding of how endomycorrhizal symbionts interact with each other, but also furnish potential tools for diagnosing the functional state of the symbiosis. Non-destructive observations can be made of vesicular-arbuscular endomycorrhizal infections in root pieces using ultraviolet light. Although this can be useful for selecting materials for biochemical analysis or electron microscope preparation, the technique is limited to young root tissues in which only living arbuscules can usually be detected. The chapter illustrates cytological, histochemical, and immunocytochemical techniques. It provides powerful tools for studying the structure and function of symbionts and their interactions in endomycorrhiza. Knowledge of the physical and chemical nature of cellular and subcellular structures permitting functional compatability in endomycorrhizal associations has been considerably improved and subcellular localization of enzyme activities has given some insight into their physiological significance for the symbiotic condition. Furthermore, by combining immunolocalization with ultra cytoenzymology it is possible to understand how the synthesis and the expression of the molecules involved are regulated.