Increase In Effective Radius Research Articles

Zonal model of nonstationary self-focusing of femtosecond laser radiation in air: effective beam characteristics evolution

The generic scenario of intense femtosecond laser pulse propagation in the air from the viewpoint of evolution of its integral effective parameters (energy transfer coefficient, effective radius, effective duration, limiting angular divergence) is considered. The analysis of variation of the effective parameters along the propagation path in the single and multiply filamentation scenarios based on numerical calculations is presented. It is shown that the process of self-action of the ultrashort radiation is characterized by the formation in a medium of the nonlinearity layer, after which optical pulse propagates quasi-linearly with the limiting angular divergence that depends mainly on initial pulse power. The effective pulse temporal duration and the effective beam radius increase after the passage through the nonlinearity layer, and their values are mostly determined by the initial beam power also. The coefficient of energy transmission of femtosecond laser radiation is lower than in the linear medium and has a tendency to decrease with the increase of the pulse power.

Critical coagulation concentration for a suspension of cation-absorptive biocolloids

Critical coagulation concentration (CCC) of a biocolloidal suspension is investigated theoretically by taking into account the influences of cationic absorption in particulate membrane phase, variation in dielectric constant, size of charged species and nonuniform distribution of fixed membrane groups. Here, an increase in both valence and effective radius of the original functional group (OFG) via absorption of electrolyte cation(s) is especially considered. The simulated results indicate that stronger membrane electricity yields a larger electrostatic repulsion and a higher potential energy, which generates a higher CCC. A lower CCC can be resulted from a larger (1) cation-functional group complex (CFGC) for a fixed difference between the radius of CFGC and that of OFG, Δ, (2) number of OFG(s) involved in the formation of a CFGC, (3) Δ for a positively charged CFGC, (4) dielectric constant of main membrane phase, in general, (5) membrane thickness for a constant amount of space-average functional groups, and (6) effective radius of anions. CCC decreases with the following parameters: (1) Δ for a negatively charged CFGC, (2) equilibrium constant of the reaction of cationic absorption, (3) nonuniform feature index of fixed groups, and (4) effective radius of cations.

Reduction of Tip−Sample Contact Using Dielectrophoretic Force Scanning Probe Microscopy

Dielectrophoretic force microscopy is shown to allow for facile noncontact imaging of systems in aqueous media. Electrokinetic tip-sample forces were predicted from topography measurements of an interface and compared with experimental images. Correlation function and power spectral density analyses indicated that image feedback was maintained without mechanical contact using moderate potentials (e.g., approximately 18 nm off the surface for a 7-Vpp, 100-kHz waveform). The applied dielectrophoretic force and the corresponding increase in effective tip radius were predictably adjusted by changing the peak potential.

Dendrimer Effects on Intermolecular Energy-Transfer of Photoexcited Triplet States of Dendritic Multiporphyrin Arrays and Electron Transfer vs Fullerene[60

Abstract Photochemical and photophysical properties of the triplet excited states of dendritic multiporphyrins arrays (nPZn, n = 1, 3, and 7) have been investigated by measuring the nanosecond transient absorption spectra in the visible and near-IR regions with changing the generation number. Intermolecular triplet–triplet annihilation rates decrease with the dendrimer generation, which was interpreted on a proposed kinetic model assuming that the excited triplet energy almost localizes in one PZn unit in nPZn. In the presence of C60, intermolecular electron-transfer takes place via the excited triplet states of nPZn (3nPZn*), yielding the cation radical of nPZn (nPZn•+) and the anion radical of C60 (C60•−) in PhCN. Deceleration of the electron-transfer rate-constants from 1PZn to 3PZn and the acceleration from 3PZn to 7PZn were observed, in which the latter tendency was interpreted by considering an increase in effective encounter radius for 37PZn*. The observed small change of the rate constants for back electron transfer between the oppositely charged species with the dendrimer generation was also reasonably interpreted by taking a smaller effective radius due to electrostatic attraction into consideration. Dendrimer generation effect was also observed for the intermolecular hole-transfer process.

Electron beam initiated modification of acrylic elastomer in presence of polyfunctional monomers

The structural changes of an acrylic rubber (ACM) in presence and absence of polyfunctional monomers like trimethylolpropane triacrylate, tripropyleneglycol diacrylate, trimethylolmethane tetraacrylate and trimethylolpropane trimethacrylate at different doses of electron beam (EB) irradiations were investigated with the help of FTIR spectroscopy (in the attenuated total reflectance mode) and sol–gel analysis. As the radiation dose increases, the concentration of carbonyl group increases in the ACM rubber due to aerial oxidation. This is corroborated from the increase in the absorbance values at 1734 and 1160 cm −1, which are due to carbonyl and C–O–C stretching frequencies, respectively. The increase in crosslinking is revealed by the increase in percentage gel content with radiation dose. The lifetime of spurs formed and the critical dose, an important criterion for overlapping of spurs have been determined for both grafted and ungrafted ACM rubber using a mathematical model. The predominance of crosslinking by electronic stopping with energetic EB projectile and the increase in effective radius of crosslinking have also been verified by this model. The doses at which the synergistic occurrence of both dislinking and endlinking steps originate have been calculated using linear energy transfer of EB. The ratio of scissioning to crosslinking for ACM rubber has been determined by using Charlesby–Pinner equation. The mechanical properties have been studied for different modified and unmodified systems and the tensile strength is found to increase with grafting of polyfunctional monomers.

Sensitivity of the First Indirect Aerosol Effect to an Increase of Cloud Droplet Spectral Dispersion with Droplet Number Concentration

Observations show that an increase in anthropogenic aerosols leads to concurrent increases in the cloud droplet concentration and the relative dispersion of the cloud droplet spectrum, other factors being equal. It has been suggested that the increase in effective radius resulting from increased relative dispersion may substantially negate the indirect aerosol effect, but this is usually not parameterized in global climate models (GCMs). Empirical parameterizations, designed to represent the average of this effect, as well as its lower and upper bounds, are tested in the CSIRO GCM. Compared to a control simulation, in which the relative dispersion of the cloud droplet spectrum is prescribed separately over land and ocean, inclusion of this effect reduces the magnitude of the first indirect aerosol effect by between 12% and 35%.

Doppler Cloud Radar Derived Drop Size Distributions in Liquid Water Stratus Clouds

A cloud particle size retrieval algorithm that uses radar reflectivity factor and Doppler velocity obtained by a 35-GHz Doppler radar and liquid water path estimated from microwave radiometer radiance measurements is developed to infer the size distribution of stratus cloud particles. Assuming a constant, but unknown, number concentration with height, the algorithm retrieves the number concentration and vertical profiles of liquid water content and particle effective radius. A novel aspect of the retrieval is that it depends upon an estimated particle median radius vertical profile that is derived from a statistical model that relates size to variations in particle vertical velocity; the model posits that the median particle radius is proportional to the fourth root of the particle velocity variance if the radii of particles in a parcel of zero vertical velocity is neglected. The performance of the retrieval is evaluated using data from two stratus case study days 1.5 and 8.0 h in temporal extent. Aircraft in situ microphysical measurements were available on one of the two days and the retrieved number concentrations and effective radii are consistent with them. The retrieved liquid water content and effective radius increase with height for both stratus cases, which agree with earlier studies. Error analyses suggest that the error in the liquid water content vanishes and the magnitudes of the fractional error in the effective radius and shortwave extinction coefficient computed from retrieved cloud particle size distributions are half of the magnitudes of the fractional error in the estimated cloud particle median radius if the fractional error in the median radius is constant with height.

巻層雲の地上観測

A ground-based observation system has been developed at the Meteorological Research Institute (MRI) for simultaneous measurements of cloud structure and radiative properties of high-level ice clouds. In this observation system, the cloud microphysical quantities and spectral radiances in the region of the 10μm window could be simultaneously observed by a Hydrometeor Video Sonde (HYVIS) and a Fourier Transform Infrared (FTIR) spectro-radiometer. On the basis of the results measured by HYVIS, the size distribution of ice particles was approximated by the power law distribution, and the simulation calculations of observed radiances were made for the some combination of the lower limit of power law distribution (γ1) and the optical thickness at 10.5μm(τ10.5). Using these data, the minimum error point is searched in the error map. By this method, we retrieve optical thickness and particle size information.The optically thin, medium and thick cases were analyzed in order to investigate the characteristic of our retrieval method. It is found that the optical thickness determined the magnitude of observed radiance, and size distributions determined the slope of the spectrum in the 860 to 980cm-1 region. The simulated and observed radiances agree within ±2mW/(m2 sr cm-1), except the 9.6μm ozone band and the root mean squares error 1.2mW/(m2 sr cm-1). The error analysis showed that though 5% systematic error is permitted to optical thickness retrieval in some cases, 1% systematic error causes large errors in the size information retrieval, and that a ±500m height error corresponds to 1 to 3% radiance error. Furthermore, the values estimated from the radiance in the region of wavenumber 860 to 980cm-1 were almost the same as those from radiance in the whole region, and the optical thickness may be determined from data in the region 1080 to 1200cm-1 without being affected by the size distribution. We also retrieved τ10.5 and effective radius (γeff) using the log-normal size distribution within the same degree of error as obtained by the power law model.Furthermore, we investigated the relationship between the parameters retrieved. The ratio of the visible optical thickness at 0.5μm(τ0.5) to the infrared one at 10.5μm(τ10.5) on June 22 is 0.4 to 1.0, and that on June 30 is 1.0 to 1.8. There is a tendency that the ratio of τ10.5 to τ0.5 becomes large as the effective radius increases. We also investigated the relation between τ10.5 and the effective radius (γeff) of log-normal size distribution. The relation between them changes case by case. There is a negative correlation between them in the case of June 22. In the case of June 30, the effective radius is scattered between 20 and 85μm.Concurrent NOAA-11 satellite data over the Tsukuba area were also analyzed. The results show that observation from the satellite is consistent with the ground based observation, and that the large difference of the brightness temperature observed by the different window channels is closely related to the existence of small ice particles of order 10μm.

Characterization of the solution properties of Pichia farinosa killer toxin using PGSE NMR diffusion measurements.

The solution behaviour with respect to pH and NaCl concentration of the tertiary structure and propensity for aggregation of salt- mediated killer toxin (SMKT) from Pichia farinosa was examined using pulsed-gradient spin-echo NMR diffusion measurements. It was found that in 0.15m NaCl the tertiary structure of SMKT was constant below pH 5.0, with the native SMKT existing as an unaggregated heterodimer containing the beta-subunit in a compactly folded form. However, above pH 5.0 the beta-subunit dissociated and lost its compact structure, becoming a random coil with an approximately 37% increase in effective hydrodynamic radius. To determine the effects of NaCl concentration on the tertiary structure of SMKT, diffusion measurements were performed at pH 3.5 and NaCl concentrations up to 2M. Both the tertiary structure and aggregation state of SMKT were found to be insensitive to the salt concentration which indicates that the activity of the toxin is not a direct result of salt-protein interactions.

An Overview of Frac Packs: A Technical Revolution (Evolution) Process

Technology Today Series articles are general, descriptive representations that summarize the state of the art in an area of technology by describing recent developments for readers who are not specialists in the topics discussed. Written by individuals recognized as experts in the area, these articles provide key references to more definitive work and present specific details only to illustrate the technology. Purpose: to inform the general readership of recent advances in various areas of petroleum engineering. Introduction Several completion methods are the current options typically considered when completing oil and gas wells in unconsolidated sand reservoirs. These include(1) rate control, where the flow rate is held below the sand-production threshold or below erosional limits handling produced sand at surface; (2)screen-only completions, which are common to horizontal and extended-reachwells; (3) underreamed openhole gravel packs; (4) cased-hole gravel packs; (5)in-situ resin treatments; (6) high-rate water packs; (7) water fractures; (8)" frac packs" ; and (9) screenless frac packs. Frac packing is a developings and-control alternative, and use of this method continues to increase in both absolute numbers and percentage of all sand-control completions implemented. Frac-pack pumping strategies represent a definitive break in the long history of sand-control developments. Most early procedures categorically avoided pumping strategies that "break down" unconsolidated formations. Discarding the" don't-break-down" paradigm has resulted in a new generation of sand-control concepts. This paper provides a brief overview of frac-pack evolution and discusses how growing acceptance of the method is creating a revolution in well-completion practices where sand control is required. Frac-Pack Beginning Focus on frac-pack developments started about 1987 after convincing technical and economic achievements resulted from application of tip-screenout(TSO) hydraulic-fracture stimulations in North Sea chalk formations and in high-permeability Prudhoe Bay and Kuparuk field formations on the North Slope in Alaska. The TSO-fracture method significantly increases proppant loading in a fracture, providing substantial conductivity improvement. High fracture conductivity resulted in dramatic and sustained productivity improvements and prompted application of TSO-fracture stimulation in high-permeability, unconsolidated formations. Amoco experimented with completions in 1964 in the Hackberry field, Louisiana, that included fractures in conjunction with sand-control completions(call "hack fracs"). The term frac pack was actually used as early as the late1950's by Shell in Germany for sand-control completions that were fractured before gravel packing. Current use of frac pack refers to completions that combine TSO hydraulic-fracture stimulation pumped with a gravel-packscreen packer assembly in place. The TSO fracture creates a short, highly conductive fracture that is designed to bypass near-wellbore damage. The gravel-pack screen assembly prevents proppant flowback. The proppant/formation interface establishes a stable barrier, preventing sand production. This increase in effective wellbore radius reduces (and often eliminates) positive skin and mitigates factors related to fines-migration problems (see Figs. 1through 3). Frac-pack case histories from the Gulf of Mexico, Europe, Africa, South America, and the Asia-Pacific report increased productivity and effective sand control. In the past 10 years, the use of frac-pack completions has steadily increased in both absolute numbers and as a percentage of sand-control completion methods deployed throughout the world. Significant investment by the service sector has increased the number of purpose-built fracture boats for offshore operations in the past 4 years. Further expansion of these resources is under way. Frac packs are often considered whenever and wherever sandcontrol is required. During the early frac-pack development period, operator and service company innovators often discussed minifracture interpretation methods, design strategies, implementation techniques, and job procedures. Sharing of experiences, observations, concerns, and nonproprietary results was fairly widespread. This open dialogue significantly accelerated frac-pack evolution. In 1992 and 1993, SPE chapters in Houston and Lafayette, Louisiana, sponsored meetings and study-group sessions to present frac-pack developments and address opportunities to improve frac-pack techniques and procedures. The SPE Gulf Coast Section organized a 1-day frac-pack workshop in 1994 and has held three more since. In 1996, "Frac Packs and Other Sand Control Methods" was an SPE Forum Series in North America topic. All these technology exchange sessions had excellent industry participation. Early Concerns At the beginning of the frac-pack revolution, application of TSO-fracture stimulation to highly deviated, typical Gulf of Mexico wells was a controversial concept and many concerns were voiced. The most frequently stated issues were increased cost, inadequate gravel-pack tool capabilities, fear of fracture-height growth into nearby water sands, and lack of coincidence between a vertical fracture and a deviated wellbore.

Some effects of galaxy structure and dynamics on the Fundamental Plane

We examine the effects on the Fundamental Plane (FP) of structural departures from an R^{1/4} galaxy light profile. We also explore the use of volumetric as well as projected galaxy parameters. We fit the Sersic R^{1/n} law to the V-band light profiles of 26 Virgo ellipticals, where `n' is a shape parameter that allows for structural differences amongst the profiles. The galaxy light profiles show a trend of systematic departures from a de Vaucouleurs R^{1/4} law, in the sense that `n' increases with increasing effective half-light radius R_{e}. Adjustments to the measured velocity dispersion are also made, based upon the theoretical velocity dispersion profile shapes of the different R^{1/n} light profiles. We find that allowing for broken structural homology through fitting R^{1/n} profiles, but still using central velocity dispersions, actually increases the departure of the observed FP from the virial plane - the increase in effective radius with galaxy luminosity (and `n') is over-balanced by an associated decrease in the mean surface brightness. In examining the use of volumetric quantities and allowing for the different velocity dispersion profiles corresponding to the observed light profiles, we find that use of the volumetric velocity dispersion at the volumetric half-light radius decreases the departure of the FP from the virial plane. Through use of the Jeans hydrodynamical equation, we further convert the projected central aperture velocity dispersion, sigma_{0}, into the infinite aperture velocity dispersion, sigma_{tot,n} (which is equal to one-third of the virial velocity dispersion). Using both the R^{1/n} fit parameters and sigma_{tot,n} we obtain for the FP, R_{e,n}~sigma_{tot,n}^{1.44+/-0.11}Sigma_{e,n}^{-0.93+/-0.08}, where R_{e,n} and Sigma_{e,n} are the radius and surface brightness terms.

Interpretation of ionic strength dependencies of the electron transfer in the Cytochrome c-Cytochrome b 5 system for the wild-type and lysine-mutated yeast Cytochrome c

Ionic strength dependencies of electron transfer between Cytochrome b5 and variants of yeast Cytochrome c were analyzed by curve fitting to the simple model of the electrostatic interaction between the two proteins assuming the process to be non-diffusion-controlled. Mutagenesis of Lys79, but not Lys72, leads to an increase of effective radius of the interacting charged species, suggesting that the mutation effects of the two residues on the electrostatic field distribution near the contact site are different, even within the crude electrostatic model used. Extrapolation of the ionic strength dependencies to infinite ionic strength resulted in similar values, around (2–3)×10-6 for all Cyt c variants considered thus showing the lysine residue mutations to primarily affect protein association rather than the electron transfer directly. Based on the ionic strength dependencies of binding constants of the two proteins into an electrostatically stabilized complex, the monomolecular electron transfer rate constant was estimated to be 1.1×104–1.6×105 s-1. The electrostatic part of the binding energy of the complex at I=0.19 was estimated to be-2.4 kcal/mol, strongly at variance with the values-13.0 and-6.4 kcal/mol reported for the two types of complexes identified using Brownian dynamics techniques. Possible reasons for this discrepancy are discussed.

CO/sub 2/ lidar technique for observing characteristic drop size in water clouds

An analytical evaluation which demonstrates that a calibrated 10.6- mu m-wavelength lidar can measure the mean radius and the effective radius of the drop size distribution in a water cloud is discussed. The radius parameter observed is a weighted average over the penetration depth of the pulse, with weighting factor decreasing with optical depth. In this method the lidar signal is integrated and boundary conditions on optical depth are applied to obtain the average extinction-to-backscatter ratio. The radius parameter is determined by comparing the measured ratio with that found from Mie scatter calculations for a variety of typical drop size distributions. This extinction-to-backscatter method was originally proposed in the literature for measuring mode radius, but at 10.6- mu m wavelength the current results show better accuracy for mean or effective radius. Sources of error are discussed. A lidar probed the sides of fair-weather cumulus clouds in the first application of this method. The resulting values of effective radius were reasonable, and the expected increase of effective radius with height was observed. >

Coverage dependence of adsorption-site geometry in the Cs/Ru(0001) system: A low-energy electron-diffraction analysis.

The ordered overlayer structures formed by Cs adsorbed on a Ru(0001) surface were analyzed by use of low-energy electron diffraction (LEED). The phase diagram reflects the dominance of dipole-dipole repulsions between the adparticles and comprises quasiliquid configurations characterized by diffraction rings up to a coverage \ensuremath{\Theta}=0.17, followed by a (2\ifmmode\times\else\texttimes\fi{}2) structure with maximum intensity of the diffraction spots at \ensuremath{\Theta}=0.23. Beyond \ensuremath{\Theta}=0.25, a series of structures with rotated unit cells is identified which are followed by a (\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 )R30\ifmmode^\circ\else\textdegree\fi{} structure around \ensuremath{\Theta}=0.33 (\ensuremath{\approxeq}completion of the first monolayer). In the (2\ifmmode\times\else\texttimes\fi{}2) phase the Cs atoms are located in on-top sites with a Ru-Cs bond length of 3.25\ifmmode\pm\else\textpm\fi{}0.08 \AA{}, corresponding to a hard-sphere radius of 1.9 \AA{} for the Cs atom. In the (\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 )R30\ifmmode^\circ\else\textdegree\fi{} structure, on the other hand, the adatoms occupy threefold hollow hcp sites with Ru-Cs bond lengths of 3.52\ifmmode\pm\else\textpm\fi{}0.02 \AA{}, corresponding to a Cs hard-sphere radius of about 2.2 \AA{}. The increase in bond length and effective radius of the adparticle is paralleled by the transition of the character of bonding from more ``ionic'' at \ensuremath{\Theta}=0.25 (large dipole moment) to more ``metallic'' at \ensuremath{\Theta}=0.33 (dipole moment reduced by about 30%). The associated change of the type of adsorption site (from on-top to hollow) is qualitatively rationalized by a model according to which inherently less favorable sites may become preferred due to improved effective screening of the dipole-dipole repulsion by the location of substrate atoms in the region between neighboring adatoms.

Some observations of the optical properties of clouds. I: Stratocumulus

AbstractAircraft measurements of broad‐band solar irradiances together with radiance measurements in the 1‐2 to 2‐1 μm region are presented for a stratocumulus sheet. Measurements of the solar albedo and cloud physics parameters indicate that the cloud was very uniform and optically thick. Broad‐band observations of albedo agreed well with calculations but observed absorption was about double the model values. Narrow‐band observations of vertical reflectance at three wavelengths suggested a marked increase in effective cloud droplet radius along the cloud, which was not observed. Some evidence that the discrepancy might be due to cloud top unevenness is presented.

Drain Tube Opening Effects on Drain Inflow

Laboratory tests were conducted to determine the effects of total opening area, location of openings and gravel envelope on radial flow to 100 mm (4 in.) diam corrugated plastic drains. Radial flow theory was used to evaluate the effective drain tube radius, re, and the drainage transfer coefficient for the corrugated tubes. The effective radius increased with total perforation area as expected, but the location of the drain tube perforation had little effect on re. The greatest increase of effective radius for an increase in perforation area occurred between areas of 38-75cm2/m where re increased from 5 mm to about 21 mm. Use of a 50 mm thick gravel envelope resulted in an increase in the effective drain radius for a 100 mm diam pipe from 5–36 mm. Experimental results for the effective radius were compared to theoretical values obtained from an earlier solution for circumferential openings. The experimental results were in close agreement with predicted values for a 1.0 mm opening width.

A Method of Analyzing Performance of Gravel-Pack Completions in Seria Field, Brunei

A method of evaluating gravel-pack completions has been developed that allows the use of small samples of observed data with large variance to be checked against theoretically derived values-in this case, the normalized productivity indices. The results give insight into the mechanics of productivity indices. The results give insight into the mechanics of impairment and lend support to previously suspected causes of impairment. Introduction Brunei Shell Petroleum (BSP) Co. Ltd.'s Seria field produces from shallow, unconsolidated, depleted produces from shallow, unconsolidated, depleted sands. The majority of wells require sand control during their production lifetime, and over the years many gravel packs, both openhole and inside packs, have been placed. The productivities achieved by the various gravel-pack repair techniques have been difficult to analyze due to the few reliable data points and wide range of values. Therefore, a statistical test was used to compare actual productivity indices (PI's) before and after gravel packing with theoretically derived PI's. The effects on productivity of different types of gravel packing and different gravel sizes also were compared. packing and different gravel sizes also were compared.To do tills it was necessary to establish theoretical values for the specific PI's (RB/D/psi/ft) of the various pack configurations using Seria reservoir data and completion sizes. The changes in well productivity as a result of gravel packing were calculated theoretically for the various gravel-pack types and placement methods by considering the individual pressure drops through the sequential resistances to flow imposed by gravel and liner and by considering these resistances as apparent skin factors in the flow equation. The equations were developed using typical Seria field reservoir data and completion sizes. Gravel-Pack Types There are two basic types of gravel packs used in BSFs Seria field: openhole gravel packs (OHGP) and inside gravel packs (IGP). Openhole Gravel Packs An OHGP consists of a slotted liner or wire-wrapped screen in an open hole, packed around with gravel. The openhole section normally is underreamed to increase the effective wellbore radius and pack thickness. This is achieved simply in a new completion; in an existing completion this requires milling a window in the casing, sidetracking, underreaming, and then gravel packing. This is referred to as a sidetracked underreamed gravel pack (STUGP). pack (STUGP).OHGP's allow completions with little apparent PI impairment and not too severe PI decline with continuing production. It will be shown later that in practice severe pack impairment does occur but practice severe pack impairment does occur but largely is offset by the increase in effective wellbore radius as a result of the underreaming. JPT P. 496

Change in the porous structure of macroporous styrene-divinylbenzene copolymers under the effect of polymer-analogue transformations

A study has been made of the dependence of the parameters (specific surface, total pore volume, mean effective pore radius) of the porous structure of styrene-divinylbenzene copolymers modified with solvents, on the nature of the ion active groups introduced into these copolymers. It has been shown that the specific surface is substantially reduced under the effect of polymer analogue transformations and the total pore volume is somwhat lowered, but the mean effective pore radius increases. The reduction in specific surface becomes more pronounced as the basicity or acidity of the ion active groups introduced into the polymer is increased.

Study of breaking characteristics of macroporous anion exchange resins

A study was made of the relation between breaking load and deformation in breakdown of porous anion exchange resins and the overall pore volume, mean effective pore radius and degree of crosslinking. It was shown that with an increase in overall volume and mean effective pore radius by one order of magnitude, breaking load decreases by 2 orders and breaking deformation decreases by half. It was found that a reduction in the mean effective pore radius to 60 Å considerably increases breaking behaviour. Breaking deformation is mainly affected by the mean effective pore radius and the degree of crosslinking. Breaking behaviour is thus fairly sensitive to a variation in structural parameters of porous anion exchange resins.

Theoretical Analysis of the Behavior of Mercury plus Thallium Iodide Arc Lamps with Variable Mercury Loadings

A theoretical analysis of the behavior of 400-watt Hg + TlI arc lamps with variable mercury loadings is performed. It is quantitatively shown that, as the Hg loading is doubled, the following effects may be predicted: (a) the effective arc temperature decreases from 5100 K to 4800 K, (b) the effective radius increases by ~10%, (c) the escape factor for the imprisoned Tl 5350 A line increases ~40%, (d) the power radiated in the Tl 5350 A line increases ~10%, and (e) the power radiated in the Hg visible line decreases ~15%. These results are in agreement with the experimental observations of Larson. These effects result in an increase in the lumen-per-watt ratings, which is of technological significance. Self-absorption is an important factor in the radiation of the Tl 5350 A line, and it is shown that the experimental observations are reasonably consistent with the assumption of local thermodynamic equilibrium.