Width Of Dispersion Research Articles

The Aerosol-Generating Effect Among Noninvasive Positive Pressure Ventilation, High-Flow Nasal Cannula, Nonrebreather Mask, Nasal Cannula, and Ventilator-Assisted Preoxygenation

To evaluate aerosol dispersion and exposure risk during oxygenation therapy among health care personnel. This study compared the aerosol dispersion effect produced through continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP), BiPAP with face coverings, a high-flow nasal cannula (HFNC) with face coverings, nasal cannula oxygenation (NCO) at 15 L/min with face coverings, nonrebreather mask (NRM), and ventilator-assisted preoxygenation (VAPOX) during oxygenation therapy at a minute ventilation of 10 L/min and 20 L/min. The length and width of aerosol dispersion were recorded, and aerosol concentrations were then detected at a mannequin's head, trunk, and feet. The average length dispersion distance of CPAP was 47.12 cm (SD, 12.56 cm), of BiPAP was 100.13 cm (SD, 6.03 cm), of BiPAP with face coverings was 62.20 cm (SD, 8.46 cm), of HFNC with face coverings was 67.09 cm (SD, 12.74 cm); of NCO with face coverings was 85.55 cm (SD, 7.28 cm); and of NRM was 63.08 cm (SD, 15.33 cm); VAPOX showed no visible dispersion. The aerosol concentrations at the feet under CPAP and at the head under BiPAP were significantly higher than those observed without an oxygen device. Compared with no oxygen device, the aerosol concentration with HFNC was higher at the mannequin's head, trunk, and feet; whereas it was lower with VAPOX and NRM. Moreover, when translated to the number of virus particles required to infect medical personnel (Nf), VAPOX took more time to achieve Nf than other devices. Strong flow from the oxygenation devices resulted in increased aerosol concentrations. CPAP at the feet side, BiPAP at the head side, HFNC, and NCO with face coverings significantly increase aerosol exposure and should be used with caution. Aerosol concentrations at all positions were lower with NRM and VAPOX.

Slab Culvert Design as a Review

Abstract: Culverts are the monolithic structure made to pass across a roadway, railway lines etc. Soil strengthening is most to balance the flood water on both sides. It follows the traffic, water deigning, walking purpose, and any other activity is taken on culverts. The risk follow water level and up word and downward flooding is most important earth to reduce, water level reducing risk for the flooding. The structures to accomplish such water flow and traffic flow without any disturbance flow across the road are called culverts, small and major bridges depending on their span such as major span, lesser span it is totally depend on water flowing discharge. Culverts are commonly used both as cross drains for channel release and to pass water under a road at natural drainage and river crossings. Drains can be of changed forms such as circular arch, span, flat slab etc. Culverts can be built with different substantial material such as masonry, concrete, Bricks, stone or reinforced cement concrete. The structural elements are required to be designed to withstand to safety point and design structure and economical with all criteria are competed such as maximum bending moment and shear force. This research Paper provides full thoughts on the provisions in the Codes, design criteria, considerations and justification of all the above aspects on design. Culverts are required to be provided under earth embankment for crossing of water course like streams, Nallas across the embankment as road embankment cannot be allowed to obstruct the natural water way without any obstruction. The structural design involves consideration of load cases Slab empty, full, surcharge loads and design criteria are covered. And factors like live load, actual width, braking force, dispersal of load through fill, impact factor, co-efficient of earth compression etc. Applicable IRC Codes are compulsory to be mentioned in the examination and design of Slab ducts. The aim of this project is to analyse the Slab Culvert using STAAD PRO software. The structural basics of Slab Culvert are designed to resist maximum bending moment and shear force. The results obtained from STAAD in Research paper are almost similar to manual calculations as per the authors are suggested. The factor consideration cushion Depth, coefficient of earth pressure for lateral pressures on walls, width or angle of dispersion for live loads on Slab without cushion and with cushion for structural deformations are important items. The IS standard requirements in the design manual for roads and bridges (IRC-6-2000, IS 21- 2000) is used in the structural designing of concrete Slab Culverts. Keywords: culvert, types of culverts, IRC Condition, Software, Percent reinforcement, Pressure Cases, Side walls, Top slab.

Cell Population Data (CPD) for Early Recognition of Sepsis and Septic Shock in Children: A Pilot Study.

Objectives: Innovative Cell Population Data (CPD) have been used as early biomarkers for diagnosing sepsis in adults. We assessed the usefulness of CPD in pediatric patients with sepsis/septic shock, in terms of early recognition and outcome prediction. We revised 54 patients (0–15 y) admitted to our Pediatric Intensive Care Unit (PICU) for sepsis/septic shock during a 4-year period. Twenty-eight patients were excluded, 26 septic patients were enrolled (G1). Forty children admitted for elective surgery served as controls (G2). Data on five selected CPD parameters, namely neutrophils fluorescence intensity (NE-SFL), monocytes cells complexity (MO-X), monocytes fluorescence intensity (MO-Y), monocytes complexity and width of dispersion of events measured (MO-WX), and monocytes cells size and width dispersion (MO-WZ), were obtained at time of PICU admission (t0) by a hematological analyzer (Sysmex XN 9000®). As the primary outcome we evaluated the relevance of CPD for diagnosing sepsis/septic shock on PICU admission. Furthermore, we investigated if CPD at t0 were correlated with C-reactive protein (CRP), patient survival, or complicated sepsis course.Results: On PICU admission (t0), NE-SFL, MO-WX, and MO-Y were higher in sepsis/septic shock patients compared to controls. NE-SFL values were correlated with CRP values in G1 patients (r = 0.83). None of the five CPD parameters was correlated with survival or complicated sepsis course.Conclusion: We found higher values of NE-SFL, MO-WX, and MO-Y in children with sepsis/septic shock upon PICU admission. These parameters may be a promising adjunct for early sepsis diagnosis in pediatric populations. Larger, prospective studies are needed to confirm our preliminary observations.

Molecular dynamics in the supercooled liquid and glassy states of bezafibrate and binary mixture of fenofibrate

Two solubility limited pharmaceuticals bezafibrate and fenofibrate, belonging to BCS class II drugs, were compared, by investigating molecular dynamics of the former and compared with the neat and as a probe in an apolar host polystyrene of mole. wt. 800 (PS800) of the latter by broadband dielectric spectroscopy (BDS), other supporting thermal and spectroscopic experimental means and density functional theory (DFT) calculations. The BDS experiments from frozen glassy state to vibrant molten state of the title drugs were done to explore the role of parameters describing their complex molecular dynamics and the stabiliy of amorphous phase, such as glass transition temperature (Tg), temperature dependence of α-relaxation times (τα), width of structural dispersion and its role on the occurrence of Johari-Goldstein (JG) β-relaxation, fragility index (m) and apparent activation energy of secondary processes. Realizing that most of the pharmaceuticals have narrow α-dispersion which limits the visibility of JG β-relaxation as a separate process in the dielectric window, to resolve the conundrum, we have further explored the amorphous dynamics of fenofibrate as a probein an apolar host polystyrene of molecular weight 800 (PS800) having higher Tg than the polar probe. The Tg of bezafibrate and PS800-fenofibrate mixture were determined to be 298 K and 275 K respectively, whereas the fractional exponent of Kohlrausch–Williams–Watts function βKWW of bezafibrate was determined to be 0.68 which is closer to that of fenofibrate, whereas that of PS800-fenofibrate mixture was found to be much broader with a value of 0.39, all in the vicinity of Tg. Even though βKWW decreased in binary mixture of fenofibrate when compared to its pure form due to concentration fluctuations and other aspects, but cold crystallization tendency was absent and Tg is elevated than that of fenofibrate. Due to higher Tg than that of fenofibrate, amorphous bezafibrate is more stable than fenofibrate. Finally, using quantum computational calculations using DFT, the relevant flexible parts of the two drug molecules, whose motions manifests the secondary γ-relaxation was identified by calculating potential energy barriers and dipole moments on relaxed dihedral angle scans, as no experimental technique is available for this purpose.

The Utility of Leucocyte Cell Population Data and Scattergram in Rapid Identification of Acute Promyelocytic Leukemia

Introduction: Acute promyelocytic leukemia (APL) is one of the hematological emergencies requiring early detection and treatment. The hematology laboratory plays a pivotal role in management. The correct morphological identification of APL is made even before the confirmation by the cytogenetic or molecular analysis. Automated hematology analyzers are the backbone of the hematology laboratories. Other than providing routine counts and differentials, they are also capable of producing sufficient information in the form of leucocyte cell population data (CPD) scatter plots depicting the leucocyte subpopulation. These data are primarily underutilized, particularly in assessing the lineage of various hematopoietic neoplasm. Here we analyzed the utility of leucocyte CPD and the pattern of scatter plot in Sysmex XN 1000 analyzer for the detection of acute promyelocytic leukemia. Materials and Results: We included 100 controls and 100 AML cases. Leucocyte CPD parameters were compared along with scatter plots from the WDF channel from Sysmex XN1000 analyzer were recorded and analyzed. Immunophenotyping and molecular analysis confirmed the diagnosis in all but two cases, where the patients expired within a few hours of admission in the emergency. Out of a total of 100 cases, 22 were labeled as APL, 63 as AML, and 15 as AML M4/M5. Among the APL cases, in 19 cases, immune-phenotyping was done on peripheral blood, and the remaining three bone marrow aspirate samples were used. The scatter-plot analysis of APL cases showed a characteristic pattern which differentiated this entity from other acute myeloid leukemias. In the case of APL, on Side Fluorescence Light Scatter (SFL) Vs. Side scatter (SSC), the abnormal promyelocytes occupy the space above neutrophils and to monocytes' right, where the immature precursors of myeloid are usually found. In cases where the total leukocyte count was within the normal range, a hiatus between these abnormal promyelocytes and neutrophils are seen. This finding was consistent in all cases irrespective of the morphological variation. On the other hand, other variants of acute myeloid leukemias along with monoblastic leukemias, the scatter plots show the blasts in the monocytic region with extension to the ceiling. On comparison, the myeloblast and monoblasts lie more towards the y-axis than abnormal promyelocytes. All the CPD parameters were compared against the control group and the AML group. The cell population data showed a significant difference in all the parameters representing the side fluorescence, size and granulations except LY-WX (width of dispersion of side scatter) when compared to normal healthy controls. Amidst all the AML cases, APL significantly differed from other cases in NE-SFL, LY-WY, and MO-WZ. AML M4/M5 and APL also varied in LY-Y, NE-WY, NE-WZ, and MO-WY. AMLs excluding AML M4/M5 showed additional variation in MO-Y and MO-Z. Discussion: APL cases have a characteristic scatter plot patter on SFL Vs. SSC. The scatter-plot shows a tear-drop like a collection of cells. These cells have high side scatter and high lateral fluorescence owing to the large size of the cells, apple-core like the nucleus, and dense granulations. The differences in the CPD parameters among APL cases and controls and other acute myeloid leukemia can be attributed to these morphological features of the abnormal promyelocytes. Haider et al. found a significant difference between NE-SFL and other myeloid leukemia. [1] This was in corroboration with our findings. Another research done by Park et al. showed that NE-SFL and MO-WX had the highest sensitivity and specificity in differentiating APL from other AML. [2] Conclusion: We conclude that the new age automated cell counters provide numerous data that remains unexplored and can be utilized further along with the information from the scatter plots to make a rapid diagnosis of Acute Promyelocytic Leukemias.

A novel complete blood count-based score to screen for myelodysplastic syndrome in cytopenic patients.

The diagnosis of myelodysplastic syndromes (MDS) is often challenging, time- and resource-consuming. A thorough analysis of complete blood count (CBC) parameters could, however, help to screen for MDS among other causes of cytopenia. To test this hypothesis, 109 newly-diagnosed MDS patients and 399 cytopenic patients older than 50years with confirmed absence of MDS were enrolled in a prospective study. Multiparametric analysis highlighted three CBC parameters that were significantly different between the two cohorts: mean corpuscular volume, absolute neutrophil count and median neutrophil complexity and width of dispersion of the events measured (Ne-WX), which were used to define an MDS-CBC score. This score enables the prediction of MDS with 86% sensitivity and 88% specificity. The MDS-CBC score excluded MDS in 89% of cytopenic controls. Moreover, high score values at MDS diagnosis significantly correlated with decreased event-free (P=0·02) and overall survival (P=0·01). The power of this score was confirmed in an independent validation cohort (MDS n=34, cytopenic controls n=28). The MDS-CBC score is an easy and fast tool to exclude or suspect MDS in unselected patients with cytopenia of unknown reasons at the time of analysis, by prompting blood smear examination. It may thus improve allocation of further MDS-specific work-up in patients with cytopenia at the time of CBC assessment.

Magnetic resonance fingerprinting with quadratic RF phase for measurement of T2* simultaneously with δf , T1 , and T2.

This study explores the possibility of using a gradient moment balanced sequence with a quadratically varied RF excitation phase in the magnetic resonance fingerprinting (MRF) framework to quantify T2* in addition to , T1 , and T2 tissue properties. The proposed quadratic RF phase-based MRF method (qRF-MRF) combined a varied RF excitation phase with the existing balanced SSFP (bSSFP)-based MRF method to generate signals that were uniquely sensitive to , T1 , T2 , as well as the distribution width of intravoxel frequency dispersion, . A dictionary, generated through Bloch simulation, containing possible signal evolutions within the physiological range of , T1 , T2 , and , was used to perform parameter estimation. The estimated T2 and were subsequently used to estimate T2* . The proposed method was evaluated in phantom experiments and healthy volunteers (N = 5). The T1 and T2 values from the phantom by qRF-MRF demonstrated good agreement with values obtained by traditional gold standard methods (r2 = 0.995 and 0.997, respectively; concordance correlation coefficient = 0.978 and 0.995, respectively). The T2* values from the phantom demonstrated good agreement with values obtained through the multi-echo gradient-echo method (r2 = 0.972, concordance correlation coefficient = 0.983). In vivo qRF-MRF-measured T1 , T2 , and T2* values were compared with measurements by existing methods and literature values. The proposed qRF-MRF method demonstrated the potential for simultaneous quantification of , T1 , T2 , and T2* tissue properties.

Toward a better understanding of dielectric responses of van der Waals liquids: The role of chemical structures

Exhaustive analysis of dielectric relaxation data of van der Waals glass-forming liquids revealed a strong correlation between the width of the frequency dispersion of the α-relaxation and the dielectric strength Δε, originating from the dipole-dipole interaction contribution to the intermolecular potential [M. Paluch et al., Phys. Rev. Lett. 116, 025702 (2016)]. The two van der Waals liquids, 4-vinyl-1,3-dioxolan-2-one (VPC) and 4-ethyl-1,3-dioxolan-2-one (EPC), have chemical structures modified from that of propylene carbonate. All three glass-formers have very similar values of dipole moments, exactly the same dielectric strength, and hence identical frequency dispersion of the α-relaxation in all three glass-formers is expected if the correlation holds. Based on this expectation, we performed dielectric relaxation measurements of the VPC and EPC at ambient and elevated pressures. The results obtained show not only identical α-relaxation frequency dispersion for the three glass-formers but also the excess wing which is the unresolved Johari-Goldstein β-relaxation. On the other hand, the other thermodynamics related parameters of the α-relaxation dynamics, including the glass transition temperature Tg, the fragility index mP, and activation volume ΔVact, are not uniformly the same for all three glass-formers.

Spin excitations in hole-overdoped iron-based superconductors.

Understanding the overall features of magnetic excitation is essential for clarifying the mechanism of Cooper pair formation in iron-based superconductors. In particular, clarifying the relationship between magnetism and superconductivity is a central challenge because magnetism may play a key role in their exotic superconductivity. BaFe2As2 is one of ideal systems for such investigation because its superconductivity can be induced in several ways, allowing a comparative examination. Here we report a study on the spin fluctuations of the hole-overdoped iron-based superconductors Ba1-xKxFe2As2 (x = 0.5 and 1.0; Tc = 36 K and 3.4 K, respectively) over the entire Brillouin zone using inelastic neutron scattering. We find that their spin spectra consist of spin wave and chimney-like dispersions. The chimney-like dispersion can be attributed to the itinerant character of magnetism. The band width of the spin wave-like dispersion is almost constant from the non-doped to optimum-doped region, which is followed by a large reduction in the overdoped region. This suggests that the superconductivity is suppressed by the reduction of magnetic exchange couplings, indicating a strong relationship between magnetism and superconductivity in iron-based superconductors.

(Invited) The Landauer Approach to Electron and Phonon Transport

Semiclassical electron and phonon transport is typically simulated by solving the electron or phonon Boltzmann transport equation. More recently, quantum transport of electrons and phonons has been simulated by the non-equilibrium Green’s function (NEGF) approach. The Landauer approach is a simple, physical approach to analyze electron and phonon transport. It is widely used to treat ballistic electron transport at the nanoscale. Less well known is that under the right conditions, it works all the way from the ballistic to diffusive limits in nanoscale to macroscale structures. The Landauer approach can also be used for phonon transport – and also from the ballistic to diffusive limits and from the nano- to macro-scales. Because the Landauer approach can be derived from the Boltzmann equation or from the NEGF equations, it provides a direct connection to more rigorous and fine-grained treatments. We believe that it should be more widely-used for three reasons: 1) it provides a smooth bridge from the ballistic to diffusive limits and from small to large structures, 2) it provides a common “language” for electron and phonon transport, and 3) it provides a clear connection to more fundamental semiclassical and quantum approaches to transport. Our goals in this talk are: 1) to review the Landauer approach to electron and phonon transport, 2) to illustrate how it compares to more rigorous treatments with some new benchmarking calculations, and 3) to illustrate how this approach helps identify good thermoelectric materials. The electrical conductance can be written as the quantum of electrical conductance, times the number of thermally active channels for electrical conduction, times the transmission. The quantum of conductance is a set of fundamental constants. The number of thermally active channels depends only on electronic structure and can be rigorously computed from first principles. The transmission is one for a ballistic conductor and small for a diffusive conductor. For large structures, this approach reduces to the traditional (Boltzmann equation) expressions of near-equilibrium electron transport. For small structures, it describes quantized, ballistic conduction. It is common to use the Landauer approach for nanostructures and the Boltzmann equation for large structures, but there is no need for two separate approaches – the Landauer approach covers both regimes of transport. The Landauer approach also applies to phonon transport using the same physical concepts described above. For example, the thermal conductance can be written as the quantum of thermal conductance, times the number of thermally active channels for phonon conduction, times the phonon transmission. This talk will present a brief overview of this technique applied to electron and phonon transport, and will discuss some new examples that benchmark the Landauer approach and illustrate the benefits and limitations of the method. It is sometimes felt that electrons and phonons are different because electrons are fermions and phonons are bosons. It turns out that this makes little difference. It does affect the thermal window functions that determine the number of thermally active channels, but the window functions turn out to be quite similar in shape. There are two significant differences – in practice, but not in principle. The first is that the energy bandwidth of the electron dispersion is typically much, much larger than the width of the thermal window function for electrons, so that simplified dispersions often work very well (e.g. parabolic energy bands). For phonons, the width of the thermal window function is comparable to the width of the phonon dispersion, so simplified phonon dispersions usually lead to large errors. The second major difference has to do with the electron and phonon mean-free-paths. Both mean-free-paths are energy-dependent, but since electrons typically occupy only a small range of energies near the bottom or top of a band, the use of a constant mean-free-path is often sufficient. In contrast, there is a very strong energy dependence of the phonon mean-free-path, and phonons with a very wide range of mean-free-paths contribute to the thermal conductivity. In spite of these technical differences, the formal equations and computational approaches are essentially identical for electrons and phonons. For most electronic devices, both electron and phonon transport play a role, and for thermoelectric devices, the intimate coupling of the two flows is critical. For problems like thermoelectrics, the use of a common approach to analyze electron and phonon transport is beneficial and can provide new insights. In this talk, we will illustrate what makes a good thermoelectric material from a Landauer perspective considering both traditional bulk and novel 2D materials as examples. Figure 1

Edge state modulation of bilayer Bi nanoribbons by atom adsorption.

We investigated the behavior of edge states in two-dimensional bilayered Bi nanoribbons by atom adsorption based on the density functional method. We found that for a clean Bi zigzag ribbon the penetration depth of well-localized edge states is a function of the momentum-space width of the edge-state dispersion. Depending on the density of adsorbed H, Br and I atoms, respectively, the edge state can be changed from localized within a very narrow region to delocalized over the whole region in real space. Changes in atomic and electronic structures and topological insulator properties associated with the atomic adsorption on the edges of zigzag bilayer nanoribbon (ZBNR) are discussed. Our work suggests that ZBNR could be a possible candidate for nanoelectronic devices under some special conditions.

Revisiting the influence of chain length on the α- and β-relaxations in oligomeric glass formers

Dielectric relaxation measurements of a series of oligo(propylene glycol) dimethyl ethers, CH3-O-[CH2-CH(CH3)-O]N-CH3, including samples with the number of PG units N = 1, 2, 3, 7, 17, 34, and 69, were made by Mattsson et al. [Phys. Rev. Lett. 94, 165701 (2005)] at ambient pressure. The objective of the study was to relate the change of properties of the glass transition dynamics to the number of monomer units N in the chain. Not examined in the previous publication is how the change of the width of the frequency dispersion of the α-relaxation with N is related to the observed change in the α-β bifurcation characterized by the ratio, τ(α)(T(g))/τ(β)(T(g)). In this paper, the frequency dispersion of the dimer, trimer, and heptamer are fitted by the Fourier transform of the Kohlrausch stretched exponential function, φ(t) = exp[-(t/τ(α))(1-n)]. Determined from experimental data, both τ(α)(T(g))/τ(β)(T(g)) and n increase with N. More interestingly, we find τ(α)(T(g))/τ(β)(T(g)) has approximately the same value as [τ(α)(T(g))/t(c)](n) with t(c) = 2 ps, in accordance with the prediction of the Coupling Model of approximate relation between τ(α) and τ(β) given by τ(β) ≈ (t(c))(n)(τ(α))(1-n). Considered also are previously unpublished dielectric loss spectra of the heptamer taken at different combinations of T and P with τ(α)(T,P) fixed by Roland et al. [Phys. Rev. B 77, 012201 (2008)]. The dielectric loss data show not only the α-loss peaks superpose but also the high frequency flank including the barely resolved JG β-relaxation superposes approximately. This is again consistent with the approximate relation between τ(α) and τ(β) from the Coupling Model because n is unchanged on varying P and T with τ(α)(T,P) kept constant, and t(c) is a constant. The additional advance made herein has the benefit of enhancing the impact of the earlier experimental studies of the oligo(propylene glycol) dimethyl ethers on current understanding of the dynamics of glass transition.

Gas-pressurized dispersive powder flow tester for low volume sample characterization

The conventional powder flow testers require sample volumes larger than 40g and are met with experimental hiccups due to powder cohesion. This study designed a gas-pressurized dispersive powder flow tester where a high velocity air is used to disaggregate powder (9g) and eliminate its cohesion. The pressurized gas entrained solid particles leaving an orifice where the distance, surface area, width and weight of particle dispersion thereafter are determined as flow index. The flow indices of seven lactose grades with varying size, size distribution, shape, morphology, bulk and tapped densities characteristics were examined. They were compared against Hausner ratio and Carr's index parameters of the same powder mass. Both distance and surface area attributes of particle dispersion had significant negative correlations with Hausner ratio and Carr's index values of lactose. The distance, surface area and ease of particle dispersion varied proportionately with circular equivalent, surface weighted mean and volume weighted mean diameters of lactose, and inversely related to their specific surface area and elongation characteristics. Unlike insensitive Hausner ratio and Carr's index, an increase in elongation property of lactose particles was detectable through reduced powder weight loss from gas-pressurized dispersion as a result of susceptible particle blockage at orifice. The gas-pressurized dispersive tester is a useful alternative flowability measurement device for low volume and cohesive powder.

Optical Studies on Methyl Methacrylate Polymerized via Metal Carbazone Complexes

Optical studies are done on Poly methyl-methacrylate (PMMA) sheets. Sampleswere previously prepared by catalytic chain transfer polymerization via metal carbazone of Cd(II) and Hg(II). Transmission and absorbance are recorded (between 190 nm to 1100 nm) as a function of incident energy using UV-VIS spectrophotometer. Second derivative of absorbance spectra is calculated to enhance differences among spectra. The optical band gap, width of band tail and dispersion of refractive index of the sheets are determined.

Fluctuation Effect in the π-Flux State for Undoped High-Temperature Superconductors

The effect of fluctuations about the π-flux mean field state for the undoped high-temperature superconductors is investigated. It is shown that fluctuations of the mean fields lead to a self-energy correction that doubles the band width of the fermion dispersion in the lowest order. The dynamical mass generation is associated with the self-energy effect due to the interaction mediated by the Lagrange multiplier field, which is introduced to impose the constraint on the fermions. A self-consistent picture about the mass generation and the propagation of the Lagrange multiplier field without damping is proposed. The antiferromagnetic long-range ordering is described without introducing an additional repulsive interaction. The theory suggests a natural framework to study spin disordered systems in which fermionic excitations are low-lying excitations.

Simultaneous numerical simulation of nano and fine particle coagulation and dispersion in a round jet

The discrete vortex method coupled with the particle-tracking and moment methods have been used to calculate the trajectories of individual nano and fine particles undergoing the coagulation and dispersion in a round jet. The results show that the Stokes number plays an important role in the dispersion of fine particles. The radial dispersion of fine particles for the wavenumber of 5 is the largest when an azimuthal perturbation is introduced to its flow. However, the width of particle dispersion is not always proportional to the amplitude of the azimuthal perturbation. As the round jet flow develops, the mass concentration of nanoparticles within the jet core decreases continuously. The number concentration of nanoparticle decreases rapidly near the jet exit, then decreases slowly in the far field until an asymptotic state is attained. Both the polydispersity and diameter of nanoparticle increase, the rate of increase for the former is the largest near the jet exit, and the largest particles are found near the jet core. The particle diameter is relatively constant across the width of the jet within and outside the jet core except the region near the interface of the jet and the outside. The standard deviation of nanoparticle size distribution increases at the jet exit, approaching slowly at an asymptotic value in the jet core. The minimum and maximum of standard deviation appear between the jet core and edge, and at the jet centerline, respectively. The region of mixing of nanoparticles becomes narrower, however, the particle number concentration grows with increasing Schmidt number. The particle size increases along the radial direction with increasing Damkohler number, and the standard deviation does not change when the Damkohler number is monotonous.

Effects of boson dispersion in fermion-boson coupled systems

We study the nonlinear feedback in a fermion-boson system using an extension of dynamical mean-field theory and the quantum Monte Carlo method. In the perturbative regimes (weak-coupling and atomic limits) the effective interaction among fermions increases as the width of the boson dispersion increases. In the strong-coupling regime away from the antiadiabatic limit, the effective interaction decreases as we increase the width of the boson dispersion. This behavior is closely related to complete softening of the boson field. We elucidate the parameters that control this nonperturbative region where fluctuations of the dispersive bosons enhance the delocalization of fermions.

Comparison of optical beam smoothing techniques for inertial confinement fusion and improvement of smoothing by the use of zero-correlation masks

We present analytic theory and numerical simulations comparing the optical beam smoothing capabilities of the smoothing by spectral dispersion (SSD) technique using random temporal phase modulation, with that of the induced spatial incoherence technique. The analytic theory provides a simple formula for the SSD mode spectrum in the usual case where the phase mask at the focusing lens is random, and its asymptotic limit quantitatively relates the long wavelength mode smoothing to the width of the angular dispersion. With parameters and phase aberration relevant to the National Ignition Facility beams, the SSD simulations show that the large long wavelength components, which are also found in earlier simulations, can be significantly reduced by replacing the independent random phase masks in each pair of adjacent beams by a conjugate pair of zero-correlation masks. These simulations suggest that one can combine zero-correlation masks with random temporal phase modulation and multiple color cycles to achieve SSD smoothing approaching the optical bandwidth limit at all spatial frequencies, without using large angular dispersions.

Fission mechanisms in the carbon-induced fission of uranium

The conventional radiochemical technique was applied to the 12 C -induced fission of 238 U at incident energies below and above the borderline for the appearance of fast fission. It supplies information on the charge dispersion and distribution of fission products in addition to the mass distribution for isolation of fast fission from ordinary fusion fission. The resulted width of charge dispersion was independent of A except for the case of the 140 MeV incident energy, where the widths at far-asymmetric mass region were definitely large compared to the normal value. On the other hand, the observed variances of mass distribution change around the threshold energy for fast fission more drastically than prediction by the model assuming that they are controlled by the stiffness coefficient and the temperature. We conclude that both results suggest the appearance of far-asymmetric mass distribution associated with the set-in of fast fission.

Chaotic transmission of waves and "cooling" of signals.

Ray dynamics in waveguide media exhibits chaotic motion. For a finite length of propagation, the large distance asymptotics is not uniform and represents a complicated combination of bunches of rays with different intermediate asymptotics. The origin of the phenomena that we call "chaotic transmission," lies in the nonuniformity of the phase space with sticky domains near the boundary of islands. We demonstrate different fractal properties of ray propagation using underwater acoustics as an example. The phenomenon of the kind of Levy flights can occur and it can be used as a mechanism of cooling of signals when the width of spatial spectra dispersion is significantly reduced. (c) 1997 American Institute of Physics.