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Severe hypertriglyceridemia is an urgent presentation that requires acute treatment. We present a rare case that could not be controlled by medical management and required plasmapheresis.

During heating and pyrolysis, the morphology and size of incipient char particles can be affected by softening, swelling, fragmentation. While fragmentation of non-swelling coal is well addressed in the literature, effects associated with swelling and softening are still scarcely understood and modeled. Under pulverized fuel-fired (PF) conditions, softening and swelling of fuel particles result in the formation of spherical and often hollow char particles. In fluidized bed conditions the presence of sand in proximity of the particles may lead to more complex phenomena. The present work attempts to investigate the behavior of different carbon rich fuels in Fluidized Bed: 1. Auguste Victoria bituminous coal (Coal); 2. a bitumen used in the cement industry (Bit); 3. a solid waste coming from the refinery industry with high metal content (RW). Tests have been carried out in a laboratory scale Fluidized Bed Reactor (40 mm id) at temperatures of 600-850 °C. Quartz sand of 200-300 ?m has been used for the bed, fluidized by a gas flow of N2 or N2/air with a superficial velocity of 0.4 m/s. The reactor was equipped by on line gas analysers. Single particles were fed from the top of the reactor and residues were collected by a basket. Coal particles had irregular shape and size of 2-4 mm. Bitumen particles were spheres of d=4-10 mm. RW particles were 10x10 mm squares. In the case of coal, the heavy/tarry species formed in the early pyrolysis stages entrap sand particles and lead to the formation of hollow aggregates. The size of the cavity is comparable with the initial particle diameter. The outer shell is larger than the original particle. Char combustion rate is slowed down by mass transfer of oxygen through the sand-enriched shell. Upon heating Bit particles undergo fast pyrolysis and the small char residue (20 %w), in presence of oxygen burns simultaneously to volatiles. RW upon pyrolysis generates large round particles, which enclose quartz sand and large cavities. Combustion of such agglomerates requires again much longer time than volatiles release due to mass transfer effects. The properties of the fuel which may be at the origin of the observed behavior are discussed.

The idea of sharing resources is a world tendency that is spreading quickly because people's behavior is continually changing due to a lot of variables, such as easy access to technology. Some examples that can illustrate this transformation are: Airbnb, Couchsurfing and Uber. Taking a look from a perspective that comprises both economy and environmental issues, vehicle sharing is a concept that brings a lot of easiness and benefits for those who used as a sustainable means of locomotion. This paper aims to contribute with a sustainable vision already adopted by Itaipu Binacional, the most important hydroelectric power plant in Brazil. To achieve this, a carsharing platform (MoVE) was developed to include electric vehicles to be used by Itaipu employees. Trying to achieve high scalability, MoVE platform offers an API that allows communication with any hardware that is capable of collecting vehicle data.

Simulation of fluidized bed combustion by commercial tools such as Barracuda or other CFD codes requires suitable kinetic models. Notably in fluidized bed reactors pyrolysis takes place with high heating rate in the temperature range of 800-900 °C and with coarse particle sizes (up to 10 mm). Therefore, intrinsic kinetics must be combined with modeling of heat and mass transfer. Intrinsic kinetics can be obtained by conventional TGA analysis at low heating rate (2-20 K/min) and with small particle size (in the order of 100 ?m). Recently a fluidized bed reactor purposely designed for operation with small particle size in combination with FTIR gas analysis has been used in Aachen to measure pyrolysis kinetics with high particle heating rate compatible with fluidized bed conditions [1]. Another innovative method to assess the rates of pyrolysis under fluidized bed conditions has been proposed by Solimene [2] in Naples and relies on the measurement of time resolved pressure. In the present work these different methodologies have been used for a German bituminous coal "Auguste Victoria" to obtain pyrolysis behavior over a broad range of operating conditions. Results show that for the two fluidized bed test rigs, using larger particle sizes, transport limitations become important. As expected, for this regime the reactions rates become lower the larger the particle size.

In the present work fast pyrolysis of coal in N2 and CO2 atmospheres was studied using two different systems: a drop tube reactor (DTR) and a heated strip reactor (HSR). The two systems allow comparable particles heating rates with different temperature of the gas phase. The tars produced in the two systems have been analyzed with the aim to study the role of gas tar reactions in soot inception. It was found that in DTR, where volatiles react in a hot atmosphere, polycyclic aromatic hydrocarbons (PAH) formation and growth is larger than in the HSR, where the volatile species are quickly quenched. The results provide evidence that secondary reactions of the tar are a source of PAH, which in turn, can be soot precursors, even in pyrolytic conditions. Also soot formation is highly limited in the HSR system, confirming the role of tar in soot formation mechanism. The effect of CO2 is not straightforward and varies according to pyrolysis time and temperature.

Previous studies have addressed the effects of carbon dioxide (CO2) rich atmospheres, as those established in oxy-firing of solid fuels, on the properties of chars produced from pyrolysis of biomass. The present work complements previous investigation with experiments carried out under high heating rate/high temperature conditions in a purposely designed heated strip reactor (HSR). Walnut shell samples have been heat treated in the HSR in N2 and CO2 at temperatures of 1573-2073 K with holding times of 3s. Primary tar has been analyzed by GC-MS, char has been analyzed by thermogravimetric analysis and Raman spectroscopy. The effect of substitution of N2 with CO2 during heat up of biomass is not straightforward, as it can result in either an enhancement or reduction of char reactivity and structural order depending on the temperature. At 1573 K, CO2 chars are less reactive and more graphitized than N2 chars. In contrast, when the temperature is increased to 2073 K, CO2 chars turn out to be more porous, less graphitized and more reactive than N2 chars. The behavior is discussed within the frame of the competition of pyrolysis, gasification and thermal annealing.

A drop tube reactor with high heating rates typical of pulverized boilers (105 K/s) has been used to carry out experiments with coal in different atmospheres: N2, CO2, O2/N2 and O2/CO2. The reactor wall temperature was set at 1573 K and the particles' residence time was kept below 130 ms. In O2/N2 and O2/CO2 atmospheres coal pyrolysis was complete and additional char conversion occurred. The degree of char conversion increased with oxygen concentration values but was further enhanced by the presence of carbon dioxide, suggesting a positive contribution of CO2 to the overall rate of conversion. Chemico-physical and structural analysis of chars revealed internal burning under regime II conditions and highlighted that the presence of CO2 favors the formation of lactones in the chars. In N2 and CO2 atmospheres the pyrolysis stage was completed, but char conversion was negligible. The combustion stage of the N2 and CO2 chars was investigated in a second stage by thermogravimetric (TG) analysis (in regime I conditions) and in a flat flame burner (in regime II conditions) to separate atmospheric effects on char formation from those on char combustion. In TG, the CO2 chars resulted to be less reactive then the N2 chars, but in the flat flame burner, the experimental rate of carbon conversion of the N2 char and the CO2 char were similar. The TG results were worked out to estimate the intrinsic kinetics of the N2 and CO2 chars towards oxygen, carbon dioxide and O2/CO2 mixtures. Kinetic rate expressions were extrapolated to regime II conditions after consideration of mass transfer limitations. Notably, the kinetic model developed for the CO2-char matched the observed rate of char (oxy-) combustion well, whereas the kinetic model of the N2-char overpredicted the reaction rate.

Background: Preventive measures to decrease the frequency and intensity of anaphylactic events are essential to provide optimal care for allergic patients. Aggravating factors may trigger or increase the severity of anaphylaxis and therefore need to be recognized and avoided. Objective: To identify and prioritize factors associated with an increased risk of developing severe anaphylaxis. Methods: Data from the Anaphylaxis Registry (122 centers in 11 European countries) were used in logistic regression models considering existing severity grading systems, elicitors, and symptoms to identify the relative risk of factors on the severity of anaphylaxis. Results: We identified higher age and concomitant mastocytosis (OR: 3.1, CI: 2.6-3.7) as the most important predictors for an increased risk of severe anaphylaxis. Vigorous physical exercise (OR: 1.5, CI: 1.3-1.7), male sex (OR: 1.2, CI: 1.1-1.3), and psychological burden (OR: 1.4, CI: 1.2-1.6) were more often associated with severe reactions. Additionally, intake of beta-blockers (OR: 1.9, CI: 1.5-2.2) and ACE-I (OR: 1.28, CI: 1.05, 1.51) in temporal proximity to allergen exposition was identified as an important factor in logistic regression analysis. Conclusion: Our data suggest it may be possible to identify patients who require intensified preventive measures due to their relatively higher risk for severe anaphylaxis by considering endogenous and exogenous factors. © 2018 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

The potential of CO2 and H2 selective polymeric membranes to separate CO2 from integrated coal gasification combined cycle power plants is examined. As a reference power plant a modified version of the Puertollano gasification plant has been defined. A detailed ASPEN model for the reference case has been developed. For the CO2 selective membranes single membrane module concepts as well as cascade concepts have been examined. The results for H2 and CO2 selective membranes show that with membranes of state of the art (CO2/H2 selectivity 15.5, H2/CO2 selectivity 5.91) the current requirements concerning CO2 purity and CO2 separation degree cannot be fulfilled. A CO2/H2 selectivity of 150 for a single CO2 selective membrane would be needed to obtain power plant efficiency losses below 10% points with separation degrees above 85%. For a cascade concept the CO2/H2 selectivity needed would be in the order of 60 to achieve the same values. For H2 selective membranes with a H2/CO2 selectivity of 50 separation degrees of 85% at efficiency losses below 10% points can be reached.

In oxy-fuel combustion, coal particles undergo pyrolysis in CO2 rich atmospheres. The composition of the gaseous atmosphere under which pyrolysis takes place may have important effects also on the formation of pyrolysis products. In the present work, pyrolysis experiments have been carried out with a medium rank high volatile bituminous coal substituting N2 with CO2. Experiments have been carried out in a laminar drop tube reactor as well as in a fixed bed reactor. CO2 chars prepared in the drop tube reactor turned out to be less reactive towards combustion than the corresponding N2 chars. Differently chars prepared at low heating rates and temperature have similar combustion reactivity regardless of the N2 vs CO2 pyrolysis atmosphere.

Several papers showed that substitution of N2 with carbon dioxide has non-trivial effects on char combustion. Previous work showed that the reactivity and properties of chars can be affected by the peculiar conditions under which pyrolysis occurs in oxy-combustion systems. In the present work, pyrolysis experiments have been carried out in a laminar drop tube reactor on a high volatile bituminous Colombian coal and walnut shells in N2 and CO2 at a temperature of 1300 °C with high heating rates of approx. 3?104 °C/s. The reactivity of the resulting chars has been analyzed by TGA. Results are compared and discussed to highlight the effect of CO2 on char properties in relation to the different parent fuel.

To validate an assistive technology (AT) baseline and outcomes measure and to quantify the measure's value in determining the best match of consumer and AT considering consumer ratings of their subjective quality of life, mood, support from others, motivation for AT use, program/therapist reliance, and self-determination/self-esteem.Prospective multi-cohort study.Vocational rehabilitation offices and community.Over 150 vocational rehabilitation counselors in 25 U.S. states with one consumer each receiving new AT.Counselor training in the Matching Person and Technology (MPT) Model and consumer completion of the MPT measure, Assistive Technology Device Predisposition Assessment (ATD PA).Total and subscale scores on the ATD PA as well as counselor-completed questionnaires.ATD PA items differentiated consumer predispositions to AT use as well as AT and user match. There were no significant differences due to gender, physical locality, or age within this sample of working-age adult consumers. Vocational rehabilitation counselors exposed to training in the MPT Model achieved enhanced AT service delivery outcomes.The ATD PA is a valid measure of predisposition to use an AT and the subsequent match of AT and user. Rehabilitation practitioners who use the ATD PA will achieve evidence-based practice and can expect to see enhanced AT service delivery outcomes.

Atomic force acoustic microscopy is a near-field technique which combines the ability of ultrasonics to image elastic properties with the high lateral resolution of scanning probe microscopes. We present a technique to measure the contact stiffness and the Young's modulus of sample surfaces quantitatively, with a resolution of approximately 20 nm, exploiting the contact resonance frequencies of standard cantilevers used in atomic force microscopy. The Young's modulus of nanocrystalline ferrite films has been measured as a function of oxidation temperature. Furthermore, images showing the domain structure of piezoelectric lead zirconate titanate ceramics have been taken.

The reactivity of persistent perfluoroalkyl radical, perfluoro-3-ethyl-2,4-dimethyl-3-pentyl ( 1 ), with various electron-donating reagents was investigated. It is revealed that 1 which is robust under oxidative conditions is rather vulnerable under reductive conditions. Thus, Lewis bases such as triethylamine and triphenylpnictogens (Ph 3 Pn, Pn=N, P, As, Sb, Bi) and some soft anions such as iodide or tetraphenyl borate reacted with 1 to give perfluoro-3-isopropyl-4-methylpent-2-ene ( 2 ) quantitatively. Even very weak Lewis bases such as diethyl ether and diethylsulfide also reacted with 1 to give 2 and additionally a hydrido product, perfluoro-3-ethyl-3- H -2,4-dimethylpentane ( 4 ). Hydrogen gas did not react with 1 at all without a catalyst, but in the presence of metal Pd adsorbed on charcoal, smoothly reacted to give 2 in quantitative yield. Metal hydrides such as LiAlH 4 , NaBH 4 , NaH, BH 3 (THF complex), Bu 3 SnH, Me 2 PhSiH reacted with 1 to give 2 and 4 . That an electron transfer mechanism is operating in the formation of 2 is obvious, but not conclusive in the formation of 4 .

Liquid-phase photofluorination (LPPF) of 2-phenyl-2-methoxyhexafluoropropane 1 gave the desired F -2-cyclohexyl-2-methoxypropane, 2 , in 21% yield. An unusual rearranged product, F -2-cyclohexylmethyl isopropyl ether, 4 , and a degradation product, F -2-cyclohexylpropane, 3 , were also produced in 10 and 20% yields, respectively. A plausible reaction mechanism for the formation of the rearranged product 4 was presented. The Cl-containing ethers with cyclic structures, 2-chlorohexafluorocyclopentenyl cyclopentyl ether, and 2-chlorohexafluorocyclopentenyl 2,2,3,3,4,4,5,5-octafluoro- n -pentyl ether were also perfluorinated by the LPPF method to give the corresponding Cl-containing F -ethers in fair yields. The total retention of the chlorine atom through perfluorination and the ability to have a benzene substituent on the substrate are benificial features of this novel perfluorinating method.

The tertiary amines derived from hexafluoropropene dimers were subjected to liquid-phase photofluorination (LPPF). The corresponding perfluorotertiary amines, which were difficult to synthesize by the conventional fluorination methods such as electrochemical fluorination and indirect fluorination using high-valency metal fluorides, were obtained in good yields. Prepared by this method were F -( N,N -dimethyl-2- methylpentyl) amine 3 , F -( N,N -diethyl-2-methylpentyl) amine 4 , F -3-(1-pyrrolidino)-2-methylpentane 11 , F - ( N,N -dimethyl-1,1-dimethyl-butyl) amine 13 . Discussion on the regioselectivity in the reaction of F -2-methyl-2-pentene (D-II) with secondary amines is also included in connection with the necessity of preparing a regioselective adduct,3-(1-pyrrolidino)- F -2-methyl-2- pentene, for the synthesis of 11 .

The preparation of a new perfluoroalkylated diamine, 5-[1H,1H-2-bis(trifluoromethyl)heptafluoropentyl]-1,3-phenylenediamine, is described. Poly(amic acid)s and polyimides were prepared from this new diamine and polyimides were evaluated as films for electronics applications. The polyimides evaluated were found to yield low dielectric constant and low moisture absorption, but were found to have exceptionally high thermal expansion coefficient. The materials are envisioned to have applications in electronics, where a low and humidity-stable dielectric constant is required.

The velocities in the mixing region of a cross flow jet injected into a freestream were studied in detail with a laser velocimeter. Three jet to freestream momentum ratios were used (3.1, 8.1, 16.2). By purposely seeding the jet and freestream separately (as well as both simultaneously), “marking” the fluid was feasible. Thus, determining the velocities that emanated from the different streams was possible. By methodically analyzing the three sets of dependent data, the size and location of the mixing region was determined. The mixing regions for the three momentum ratios were found to be of different sizes and at different locations. By proper scaling, however, the regions for the three momentum ratios were found to collapse to one scaled region. Because of the intermittent behavior of the mixing, conventional turbulence models for such mixing may not be applicable; however, detailed velocities and turbulence quantities are included for “benchmarking” predictions.

An improved method has been used to synthesize perfluoroazo-2-propane. Pyrolysis over the temperature range 450–514 K in a static system has been shown to be a homogeneous, first-order process. No pressure dependence was observed in the presence of excess inert gas (SF6). The only products were nitrogen and perfluoro-2,3-dimethylbutane. The rate constant (k) for the decomposition process is given by: These results lead to a straightforward mechanism for the decomposition process The results are compared with those for other azo compounds. © 1994 John Wiley & Sons, Inc.

A measurement technique to determine the surface heat transfer distribution in complex turbulent flows is described. For this purpose, a constant wall heat flux test surface has been designed. To measure the surface temperature of the test plate, an infrared camera was used. The instrumentation allows the determination of the heat transfer with high accuracy and detailed spatial resolution. In examining combustor-type separated flow, the capabilities of the technique are demonstrated and its accuracy is verified by appropriate conventional techniques.

Theoretical calculations of miscibility windows for binary polymer blends in which one component is an essentially alternating copolymer of tetrafluoroethylene and vinyl alcohol (FVOH) are reported. FVOH has an inherently low solubility parameter [≈ 6.2 (cal. cm−3)0.5] that is outside the range commonly encountered in miscible polymer blends and thus represents a stringent test of the predictive capabilities of an association model we have used in previous work. The application of this model requires that we determine dimensionless equilibrium constants describing the self-association of a model compound 3,4-pentafluorobutan-2-ol (PFB) at 25°C from infrared spectroscopic data. Analogous equilibrium constants for FVOH were scaled from those of PFB by taking into account differences in the molar volume of the model and the specific repeat of the copolymer (see M. M. Coleman, J. F. Graf, and P. C. Painter: Specific Interactions and the Miscibility of Polymer Blends, Technomic, Lancaster, PA, 1991). Equilibrium constants describing the inter-association of FVOH with ester type carbonyl groups were obtained from spectroscopic studies of miscible blends with poly(ethyl methacrylate). These equilibrium constant values were then used to calculate theoretical miscibility windows for the complete range of blends of FVOH with polymethacrylates, ethylene-co-methyl acrylate, styrene-co-methyl acrylate, and ethylene-co-vinyl acetate copolymers. Experimental results performed in our laboratories confirm the general validity of the predicted miscibility windows. © 1993 John Wiley & Sons, Inc.

Convective heat transfer is examined in two typical examples of separated flows, namely, the flow over a backward-facing step and a two-dimensional jet entering a crossflow. Local Nusselt numbers were determined in and behind the recirculation region. The main parameters influencing the heat transfer, the Reynolds number, and the momentum flux ratio of the jet and the crossflow have been varied over a wide range. In addition to heat transfer measurements, the flow field has been documented using an LDA system and oil film technique. The static pressure distribution at the wall within the separated flow is also given. The measurements are compared with the results of a numerical code, based on a finite volume method, where the well known k-ε model is employed. The differences in Nusselt numbers predicted with one- and two-layer models are shown to demonstrate the influence of wall functions on heat transfer. The numerical and experimental results are compared with available data, and the differences and similarities in the heat transfer behavior of separated flows are discussed.

This paper describes a novel, safe, effective technique, with a new reactor design, for the synthesis of perfluorochemicals. This method, the liquid-phase photofluorination with undiluted fluorine, is applicable to the preparative-scale synthesis of isomerically-pure branched F-alkanes, F-ethers and F-tert-amines which are difficult to prepare by the classical fluorination methods ( i.e. electrochemical or CoF 3 ). The technique is based on the controlled inverse addition of the materials to be fluorinated to a well-stirred F 2 -saturated inert solvent, with simultaneous UV irradiation. The application of this method to the synthesis of F-ethers is described: the following were made by this method, F-2-propoxy-2-methyl-pentane, F-2-isobutoxy-2-methylpentane, F-n-heptylpropylether, F-2-pentoxy-2-methoxypropane, F-3-propoxy-2-methylpentane, F-2-ethyl-2-isopropyltetra-hydrofuran, F-3-isobutoxy-2-methylpentane, F-2-methoxy-4-ethyl-4-methyl-hexane, and F-2-methyl-(1-ethyl-1-methylpropyl)oxetane.

Electron spin resonance (ESR) analysis at room temperature of the particles produced during the aerobic pyrolysis of perfluoro polymers (PFP) shows the presence of end-chain peroxyl radicals. These radicals, which would normally have lifetimes of several seconds at most, are stabilized by being immobilized in the particles and decay at a rate of about 20%/day. Normally, radicals with this stability would not be expected to be reactive; however, these peroxyl radicals react with 3-chloropropene, with iodine in benzene, with methyl linoleate in methanol, and with aqueous liposomes from soy phosphatidylcholine. Also, stable radicals of this sort would not be expected to give spin adducts; however, when the particles are suspended in a benzene solution containing alpha-phenyl-N-tert-butylnitrone (PBN), they react to give the same series of spin adducts that are detected when the unfiltered smoke from the oxidative pyrolysis of perfluoro polymers is bubbled directly into PBN solutions. This appears to be the first report of the reaction of radicals entrapped in a solid with a spin trap. The nitroxide species produced by the PBN-particle reaction include a fluorine atom spin adduct, an oxy radical adduct, and benzoyl tert-butyl nitroxide (PBNOx), the oxidation product of the spin trap; all of these appear to arise from reaction of the particle-bound peroxyl radicals with the spin trap. Because the particles are in the highly respirable range (down to 0.01 micron), these entrapped peroxyl radicals may be carried deep within the lung when fumes from PFP pyrolysis are inhaled and would be expected to place an oxidative burden on the lung.(ABSTRACT TRUNCATED AT 250 WORDS)

The AFAM technique is a sensitive method for the quantitative measurement of local elasticity, here on a scale of 200 nm. On a silicon single-crystal oriented in 〈100〉 direction, the results for the measured Young’s modulus are in good agreement with the known value, In nanoscaled thin films of ferrites with a grain size of about 70 nm, we were able to detect the difference in the elasticity caused by the deviation from the stoichiometry. With the AFAM technique, surfaces with a large enough difference in elastic modulus can be distinguished reliably. However, for reproducible quantitative measurements in the linear as well as in the nonlinear force range, the problem of sensor tip stability is not yet solved. This could be made possible either by using more stable diamond tips with larger radii or by working in a controlled environment to reduce adhesion by meniscus forces. Modeling the nonlinear behavior of the contact resonances, as for example the hysteresis, would allow one to gain further information about the interaction forces. Finally, there are two techniques to image ferroelectric domains in PZT material. They can be made visible by anisotropic etching. In that case one can only image a frozen-in state of the surface. A life image, however, can be obtained by the inverse piezoelectric effect allowing one to examine the domain dynamics.

We have modified an Atomic Force Microscope (AFM) that allows the detection of cantilever bending as well as torsional vibrations at ultrasonic frequencies. Oscillating either probe tip or sample vertically modulates the normal force about the setpoint force, acting between tip and sample. When the tip contacts the sample, the surface resists the oscillation and deformation of the sample is dependent on the local stiffness or elasticity. For a constant normal force, a soft area deforms more than a hard area and thus the cantilever deflection is less over a soft area. The variations in cantilever vertical oscillation is a measure of relative elasticity of the sample. Elasticity maps with a lateral resolution of better than 100 nm have been taken on alumina-based ceramic composite, and on two metal particle (MP) recording tapes. By vibrating the sample laterally, the shear forces are modulated. Detecting and analyzing the cantilever torsional behavior, we are able to characterize friction and viscosity of thin films used for lubrication of magnetic disks.

Investigations on the combustion of a blend of liquid refinery residues and a hard coal are presented in the current paper. The experiments were done in an atmospheric circulating fluidized bed combustor (CFBC) with a thermal capacity of 100 kW. The operation behaviour and pollutant formation characteristics are determined using axial profile measurements at 19 different ports along the combustion chamber. The measurement campaign included the variation of the primary to secondary air ratio, the global air to fuel ratio, the residence time in the primary zone, the overall temperature of the combustion chamber and the Ca/S ratio. The current paper concentrates on results obtained at primary air ratio of 0.65, an overall air ratio of 1.1, a mean combustion temperature of 850°C and a Ca/S-ratio of 0. Measurement of the flue gas components O2 , Cx Hy , CO, CO2 , H2 , NOx , N2 O, NH3 and SO2 are made by standard gas analysing techniques. In order to detect the specific hydrocarbon species produced and oxidized during the combustion process a Fourier Transformation Infrared Spectrometer (FTIR) extends the existing gas analysis system. The gas species measured by FTIR-Spectroscopy are CH4 , C2 H2 , C2 H4 , C2 H6 , C3 H6 and C3 H8 . Also the important precursors for the NOx -Formation HCN and NH3 are examined with the FTIR-Spectrometer in the primary and secondary zone. The current experiments are compared with results obtained by burning liquid refinery residues only, with special regard to the consumption of the nitrogenous intermediates HCN and NH3 .Copyright © 2005 by ASME

Dynamic Atomic Force Microscopy (AFM) modes, where the cantilever is vibrated while the sample surface or tip is scanned, belong to the standard features of most commercial instruments. With these techniques images can be obtained the contrast of which depend on the elasticity of the sample surface. Quantitative determination of Young's modulus of a sample surface with AFM is a challenge, especially when stiff materials such as hard metals or ceramics are encountered. The evaluation of the cantilever vibration spectra at ultrasonic frequencies provides a way to discern local elastic data quantitatively using the flexural vibration modes. Nanocrystalline magnetic materials, multi- domain piezoelectric materials, polymeric materials, diamond-like carbon layers, silicon, and soft clay have been examined. Images obtained at the contact resonance frequencies are presented whose contrast is based on the elastic differences of the surface structure of the various materials examined. The spatial resolution is approximately 10 nm. Applying an electrical ac-field between the tip and the surface of a piezoelectric sample, images can be generated whose contrast is additionally influenced by the piezoelectric and dielectric properties of the sample. Furthermore, we present a new approach for studying friction and the stick-slip phenomenon using the torsional resonances of AFM cantilevers.

To study Draeger's self-tonometer handling and accuracy.This microprocessor-controled applanation tonometer enables the patient to perform frequent measurements himself. Two studies were carried out. In a first patient series of 22 participants we analyzed patient-acceptance with regard to tonometer handling, in a second group of 10 normal eyes, 30 average readings obtained using the Draeger tonometer were compared to the results from Goldmann applanation tonometry.In the first group of 22 patients, 8 participants considered that the new tonometer was easy to handle, 7 reported moderately difficult and 6 difficult handling. One patient did not succeed in measuring at all. The results of the second group showed a statistically non significant mean difference of 0.3mmHg with a standard deviation of nearly 2 mmHg. 80.1% of measurements were within +/-2mmHg. The correlation coefficent was 0.73.Handling the self-tonometer is quite simple and provides close and reliable readings. Thus, in addition to early detection, self-tonometry offers the possibility of improved management and follow-up of glaucoma.

Generalized retinal degenerations such as retinitis pigmentosa may manifest with focal retinal dysfunctions. These may be detected objectively by new electrophysiological techniques, such as multifocal electroretinography (ERG).A mother and daughter, aged 81 and 46 years, showed bilateral caudal bone spiculae formations with corresponding cranial visual field defects in the static perimetry of the central visual field (Octopus) and in the kinetic perimetry (Goldmann).Pattern VEP, pattern ERG, EOG, and cone ERG were within the normal range. The scotopic ERG was in the lower normal range. The multifocal cone ERG of the central 50 degrees showed reduced amplitudes and prolonged latencies in the first-order response component. These findings corresponded to the area of the bone spiculae and the scotomata.Multifocal ERG enables the detection of focal retinal cone dysfunction in segmental retinitis pigmentosa. It is an additional tool that may aid in the diagnosis and classification of this disease.

The precise etiology of ocular vascular occlusions is not known in all details. The pathogenesis may be associated with abnormalities of blood rheology and coagulation. Frequently, it is associated with an underlying systemic disease (Table 1). Despite many years of investigation and research, some principles of the pathophysiology and therapy of this disease entity remain unclear.

Ceramic materials with heterogeneous phase content and internal boundaries are unique in their electromechanical properties. Due to the interaction between those properties, these so-called multifunctional materials are suited for the realization of parts that have to yield complex functions in a system such as sensors and actuators. The knowledge of the materials microstructure and the elastic constants is essential for materials optimization and quality assessment. In this article, nondestructive techniques are presented to evaluate the microstructure and the elastic constants of a number of lead titanate zirconate (PZT) piezoceramics. Ultrasonic pulse-echo techniques were used to determine the elastic constants of different materials. When the piezoelectric material is poled, i.e., when the ferroelectric domains have a preferred orientation, we observe an increased sound velocity when the wave polarization is parallel to the poling direction. This elastic stiffening effect is being described theoretically. Finally, the Atomic Force Microscope (AFM) has been employed to image the ferroelectric domains of the piezoceramics. The microfabricated conductive tip of an AFM was used as a single electrode to excite vibrations of individual ferroelectric domains. Depending on their orientation, the recorded vibration amplitude varies between the domains and hence, forms a contrast.

Conventional friction force microscopy (FFM) is widely used for tribological studies of engineering surfaces. It is, however, difficult to separate friction forces resulting from interactions dependent upon interfacial material properties from surface topography-induced lateral forces. We have developed and employed a technique to operate acoustic friction force microscopy (AFFM) by oscillating the sample laterally at megahertz frequencies. The in-plane vibrations perpendicular to the longitudinal axis of the cantilever are generated because of lateral forces between the probe tip and the sample. Torsional cantilever vibrations were detected at frequencies of up to 2 MHz. A mean cantilever lift-off was observed that can be explained by elastohydrodynamic lubrication. The high-frequency torsional vibration amplitude provides information about the lateral forces that can be used to calculate the friction and viscosity of thin surface films. The AFFM images of metal-particle magnetic tapes were produced, revealing a resolution apparently better than FFM images. Unlike FFM images, AFFM images are independent of the scanning direction, indicating that AFFM images are less sensitive to topography-induced lateral forces. Also, AFFM, allows friction measurements at relative velocities of the order of 1 mm s −1 which is much larger than that obtained in conventional FFM (several μm s−1). Copyright © 1999 John Wiley & Sons, Ltd.

In this paper, the mechanism of reduction of friction by ultrasonic vibration has been studied. Experiments have been conducted by vibrating the specimen surfaces at ultrasonic frequencies. We found that vibration of the surfaces with amplitudes as low as a few nanometers evokes a super-lubricating effect when the frequency of vibration is high enough, here greater than 500 kHz. With a Pin-on-Flat (POF) test apparatus, a reduction of sliding (kinetic) friction was observed on surfaces vibrating laterally (in-plane), vertically (out-of-plane) or ellipsoidally (both in-plane and out-of-plane components). Sliding a sharp tip of an Atomic Force Microscope (AFM) against a vibrating surface revealed near-zero friction. Whereas friction is reduced, we find that a dramatic increase in wear can occur when contact resonances are excited. Thus, contact resonance can be used for ultrasonic machining.

Over the last three years ultrasonic techniques have been implemented with an Atomic Force Microscope (AFM). Using longitudinal sound waves in the MHz regime the AFM cantilever was excited flexurally in order to characterize adhesion, elasticity and subsurface properties of different samples /1/. Yamanaka and Tomita proposed the method of lateral displacement modulation to image frictional properties /2/. However, the modulation frequency was kept below the fundamental oscillation of the cantilever in use. This paper describes the application of shear waves and surface waves to generate torsional vibrations in the cantilever well above its first resonance in order to evaluate frictional properties. The shear waves, generated by either commercially available transducers or by piezoceramics on the sample back side, excite in-plane displacements on the sample surface. The polarization of the shear waves is selected to be perpendicular to the cantilever beam. In other experiments, Surface Acoustic Waves (SAW) are generated. Frictional and adhesion forces acting between the AFM tip and the sample surface transmit the surface oscillations into the cantilever. The cantilever motion is detected with a laser beam by a fast external knife-edge detector. The first results of Acoustic Friction Force Microscopy (AFFM) images using ultrasound are presented.

The successful development of cataract operation and IOL implantation in the last decade has resulted in progressive shortening of the incision length as well as in developing safer and simpler anesthetic techniques. The purpose of the present study was to evaluate whether cataract surgery with scleral incision is possible using only topical sponge anesthesia with oxybuprocaine 0.4%. This method was compared with retrobulbar injection.150 patients (3 groups each consisting 50 eyes) underwent phaco with scleral incision. 1st group: oxybuprocaine sponge anesthesia. 2nd group: oxybuprocaine sponge anesthesia combined with mild systemic analgesia (tramadol p.o.). 3rd group: retrobulbar injection (prilocaine/etidocaine mixture). All patients received medazolam premedication (Dormicum, 3/10 of 1 cc). Pain and discomfort during and after operation were investigated and statistically analyzed.Neither in group 1, 2 or 3 an additional subconjunctival injection was necessary. Pain or discomfort during operation was felt in 14 percent of the patients anesthetized with the oxybuprocaine sponge but only in 6 percent of the patients additionally premedicated with tramadol (2nd group). Also 6 percent of the patients after retrobulbar injection felt pain during operation. Postoperatively no significant differences between group 1 and 2 were obtained: 6 percent felt pain, 30 percent had a short term foreign body sensation. After retrobulbar injection (group 3) only 10 percent felt postoperative pain or discomfort.Topically applied oxybuprocaine provides sufficient anesthesia during cataract surgery with scleral incision. A combination with mild systemic analgesia (tramadol) helps to minimize pain and discomfort. Retrobulbur injection yielded only in the postoperative period significantly better analgesia. In the operating room full cooperation of the patient is required. Therefore we recommend not to use sponge anesthesia in cases when communication between surgeon and patient is insufficient.

Chronic application of beta-blockers often induces tachyphylaxia of unknown origin. After long-term topical pretreatment of pindolol and timolol in rabbit eyes (up to 12 weeks, twice a day) beta 2-adrenergic receptors were localized and quantified with autoradiographic methods. Frozen sections of albino rabbit eyes were labelled with [125I] cyanopindolol. Quantification revealed a significant increase in the density of beta 2-receptors after premedication with pindolol in the ciliary body and the corneal epithelium. This increase was detectable after 2 weeks of premedication and reached its maximum after 4 weeks. After premedication with timolol a significant increase of beta 2-receptors in the epithelium of the ciliary body and the corneal epithelium was visible. Following pindolol over an equivalent time-course, to that of timolol administrations, an increasing number of beta 2-receptor sites was also observed. No significant changes were visible for either kind of premedication investigated (pindolol/timolol) in the corneal endothelium, the lens or the choroid. Chronic application of topically instilled beta-blocking agents leads to a significant increase in receptor density in ocular structures that are involved in aqueous humor production. This up-regulation of beta 2-adrenergic receptors might explain the intraocular events at receptor level in relation to the phenomenon of tachyphylaxis.

Detailed measurements of local heat transfer coefficients are presented for air injection through a row of holes into a crossflow. Pitch-to-diameter ratios of 2,4, and 6 are realized and the momentum flux ratio is varied in the range from 0.25 to 4.0. The injection angle of the jets is fixed at 90°. The experimental technique developed uses an Infrared Camera to measure the temperature distribution on the constant heat flux test surface. This measurement technique allows detailed spatial resolution of the heat transfer and gives information about the three-dimensional mixing process of the jets with the mainstream. The experimental results indicate a large influence of the hole spacing to diameter ratio, (s/d), on the heat transfer coefficient. With s/d = 2.0, the spanwise heat transfer coefficients in the vicinity of the injection holes are noticed to be highly uniform. For momentum flux ratios, J, greater than 1, two regions of high heat transfer coefficient exist. The first region occurs in the vicinity of the injection holes. The second region observed some distance downstream is due to the reattachment of the jets to the surface.Copyright © 1991 by ASME

Submicrometer solid-particle (fume) aerosols with up to about 10(8) particles/cm3 are formed when dilute vapors of low molecular weight (MW) (ca. 5000-10,000) perfluoro polymers condense in air. The aerosol (e.g., 0.2 mg/m3) formed from these vapors is highly toxic to laboratory rats by inhalation (30-min exposure) when fresh but loses toxicity in minutes, apparently owing to coagulation. These fumes may result from (a) pyrolysis of tetrafluoroethene homopolymer or tetrafluoroethene-hexafluoropropene copolymer or (b) evaporation, at 200-320 degrees C, of isolated low MW polymer or low MW polymer present in perfluoro polymer resins. Some perfluoro polymer fume aerosols contain reactive functional groups, but others without detectable reactive groups are at least as toxic.

It is shown that microdischarges can be caused to occur between vacuum insulated electrodes by exposing the electrode surfaces to oil contamination or to the condensation of electronegative gases (H2O, CO2). The presence of the condensed H2O layers at low electrode temperatures lowers the microdischarge onset by a factor of 3 and the implication of this for microdischarge theory and vacuum cable development are discussed. A theory is presented which enables the onset of breakdown in the gas released by the microdischarge to be calculated.

Zusammenfassung Drei methoden zur Erfassung von Eisenspuren in Wolfram werden aufgrund entsprechender statistischer Kenndaten sowie anhand von Ablaufschematas kritisch miteinander verglichen. Es handelt sich um folgende Verfahren: ein losungsabsorptionsphotometrisches Verfahren mit α,α′-dipyridyl als Farbreagens; ein rontgenfluoreszenzanalytisches Verfahren mit vorheriger Spuren-Matrix-Trennung durch Spurenfallung mit 1-(2-Pyridylazo)-2-naphthol; ein atomabsorptionsspektrometrisches Verfahren ohne Spuren-Matrix-Trennung in der graphitrohrkuvette, welches mit nur 50 mg Probenmenge auskommt. Alle drei Methoden wurden nach einem kurzlich von Gottschalk vorgeschlagenen Schema standardisiert. Die Auswahl der hier angewandten Methoden aus einer Vielzahl von Moglichkeiten wird begrundet. Die Bedeutung der Durchschnittsspurenanalyse zur chemischen Charakterisierung von Metallen trotz der heutigen Moglichkeiten der topochemischen Mikro- und Spurenanalyse wird diskutiert.