scholarly journals Recent Developments in Cross Section and Panel Count Models

2016 ◽  
pp. 106-151
Keyword(s):  
Cross Section ◽  
Count Models ◽  
Recent Developments

scholarly journals Snowdrift modelling in a wind tunnel: vertical and horizontal variation of the snow flux

1998 ◽  
Vol 26 ◽  
pp. 212-216 ◽  
Author(s):  
Florence Naaim-Bouvet ◽  
Mohamed Naaim
Keyword(s):  
Wind Tunnel ◽  
Cross Section ◽  
Critical Examination ◽  
Small Scale ◽  
Geometrical Parameters ◽  
Drifting Snow ◽  
Horizontal Variation ◽  
Storm Duration ◽  
Recent Developments ◽  
Mean Wind Speed

This paper deals with the influence of the vertical and horizontal variation of Aeolian snow flux on estimations of snow-storm duration and on snowdrift patterns simulated in a wind tunnel.First of all, we shall review recent developments, including our own simulations, concerning the horizontal increase of mass flux until drifting-snow saturation has been reached.Next, after a critical examination of various snowdrift-modelling criteria, we present the results of an experiment undertaken in our wind tunnel: We studied cross-section drill-area changes behind a small-scale snow fence as a function of time for different fetches but for the same mean wind speed at the beginning of the testing section. For each fetch, we carried out vertical profiles of sand particles using image processing and we studied the geometrical parameters of the drift. We conclude dial changes in the cross-section drift area depend on the ablation length and if particle saturation is not reached, the use of a storm-duration scale leads to Overevaluation of prototype storm duration. Moreover, we point out that drift pattern vary as a function of the concentration profiles.

scholarly journals Snowdrift modelling in a wind tunnel: vertical and horizontal variation of the snow flux

1998 ◽  
Vol 26 ◽  
pp. 212-216 ◽  
Author(s):  
Florence Naaim-Bouvet ◽  
Mohamed Naaim
Keyword(s):  
Wind Tunnel ◽  
Cross Section ◽  
Critical Examination ◽  
Small Scale ◽  
Geometrical Parameters ◽  
Drifting Snow ◽  
Horizontal Variation ◽  
Storm Duration ◽  
Recent Developments ◽  
Mean Wind Speed

This paper deals with the influence of the vertical and horizontal variation of Aeolian snow flux on estimations of snow-storm duration and on snowdrift patterns simulated in a wind tunnel.First of all, we shall review recent developments, including our own simulations, concerning the horizontal increase of mass flux until drifting-snow saturation has been reached.Next, after a critical examination of various snowdrift-modelling criteria, we present the results of an experiment undertaken in our wind tunnel: We studied cross-section drill-area changes behind a small-scale snow fence as a function of time for different fetches but for the same mean wind speed at the beginning of the testing section. For each fetch, we carried out vertical profiles of sand particles using image processing and we studied the geometrical parameters of the drift. We conclude dial changes in the cross-section drift area depend on the ablation length and if particle saturation is not reached, the use of a storm-duration scale leads to Overevaluation of prototype storm duration. Moreover, we point out that drift pattern vary as a function of the concentration profiles.

e-e- Probes of the Littlest Higgs

2005 ◽  
Vol 20 (31) ◽  
pp. 7412-7422
Author(s):  
Jay G. Wacker
Keyword(s):  
Cross Section ◽  
Charge Structure ◽  
Recent Developments ◽  
The Cross ◽  
The Masses

In these proceedings the "Littlest Higgs" is discussed in depth. With recent developments it is now possible to reduce the ultraviolet insenstivities of these models and make definite predictions for the masses of all particles including the Higgs. The charge structure of the model is briefly reviewed. The cross-section for e-e- → ϕ--νeνe, is calculated and 6.2 pb is found.

Gas reaction chamber for gas-solid interaction studies by high-resolution TEM

1994 ◽  
Vol 52 ◽  
pp. 494-495 ◽  
Author(s):  
Renu Sharma ◽  
Karl Weiss ◽  
Michael McKelvy ◽  
William Glaunsinger
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Cross Section ◽  
Reaction Chamber ◽  
Side View ◽  
Transmission Electron ◽  
Environmental Cell ◽  
High Resolution Tem ◽  
Recent Developments ◽  
High Resolution Images

An environmental cell (E-cell) is a gas reaction chamber mounted inside an electron microscope column where thin solid samples can be observed under various gases (O2, H2, N2, NH3 etc.) at selected temperatures. Even though the idea of having an E-cell incorporated in the microscope column is as old as transmission electron microscopy itself, recent developments in the instrumentation and designs of both the microscopes and E-cells have made it possible to obtain high resolution images (0.3-0.6 nm). We have used the differentially pumped model proposed by Swan to modify a PHILLIPS 400T transmission electron microscope for gas-solid studies.Figure la shows a side view cross section schematic of the E-cell fitted in the 9 mm gap between twin lens objective pole pieces. It consists of a small chamber with 200 and 400 μm apertures on sides a and a’ respectively. The walls are machined at the same angle as the pole pieces for an optimum fit to the conical exterior of the pole pieces and the cell is held firmly in place with o-rings (b).

scholarly journals From LO to NLO in the parton Reggeization approach

2018 ◽  
Vol 191 ◽  
pp. 04007 ◽  
Author(s):  
Maxim Nefedov ◽  
Vladimir Saleev
Keyword(s):  
Pair Production ◽  
Cross Section ◽  
Parton Model ◽  
High Energy ◽  
Effective Theory ◽  
Leading Order ◽  
Multi Scale ◽  
Recent Developments

We present recent developments of the parton Reggeization approach (PRA), which is based on high-energy factorization of hard processes in the multi-Regge kinematics and Lipatov’s effective theory of Reggeized gluons and Reggeized quarks. The scheme of calculations in the leading order (LO) of the PRA is discussed. We present important examples of LO PRA applications for cross section calculations of multi-scale hard processes, such as pair production of BB¯-mesons, pair production of photons, and pair production of jets. Also the problem of matching of NLO calculations in PRA with NLO results in the Collinear Parton Model is discussed.

Benzoxazine resin as an interesting building block for advanced neutrons shields

2021 ◽  
pp. 095400832110218
Author(s):  
Oussama Mehelli ◽  
Mehdi Derradji ◽  
Abdelmalek Habes ◽  
Nour Elislem Leblalta ◽  
Raouf Belgacemi ◽  
...  
Keyword(s):  
Cross Section ◽  
Research Reactor ◽  
Building Blocks ◽  
Mean Free Path ◽  
Sample Thickness ◽  
Experimental Setup ◽  
Reinforced Composites ◽  
Neutron Shielding ◽  
Recent Developments ◽  
Macroscopic Cross Section

The design of lightweight neutrons shields has been restricted for quite some time to the use of the epoxy thermosets as the main building blocks. Meanwhile, the recent developments in the field of polymers suggest otherwise. Indeed, benzoxazine resins have taken the lead over the traditional thermosets in many exigent applications. Therefore, in a vision to introduce newer matrices with better performances and to further expand the applications of the benzoxazine resins into the nuclear field, the neutron shielding efficiency along with the thermal and thermomechanical performances of the neat benzoxazine polymer and its subsequent B4C-reinforced composites were investigated. The neutron shielding measurements were performed using an optimized experimental setup at NUR research reactor, Algiers. The neat benzoxazine polymer displayed almost similar thermal neutrons screening performances than the epoxy with a macroscopic cross-section (Σ) of a 0.724 cm− 1 equivalent to a mean free path (λ) of 0.957 cm. The effect of the particle amount was also studied to maximize the shielding ability of the developed materials. For instance, the benzoxazine composite containing 20 wt.% of B4C displayed the outstanding screening ratio of about 96% for a sample thickness of 13 mm. Finally, the remarkable findings were put into context by providing multifaceted comparisons with the available shielding materials.

Conversaziones, 1968

1968 ◽  
Vol 23 (2) ◽  
pp. 119-126
Keyword(s):  
Cross Section ◽  
Power Transmission ◽  
Helium Temperature ◽  
New Materials ◽  
Ohmic Losses ◽  
Composite Conductors ◽  
Electrical Devices ◽  
Power Transmission Systems ◽  
Recent Developments ◽  
Niobium Titanium

CONVERSAZIONES were held this year on 16 May and 27 June. At the first conversazione there were twenty-three exhibits and two films shown. Recent developments in superconducting materials have made it possible to realize electrical devices and power transmission systems which will operate without ohmic losses at liquid helium temperature. An exhibit in three parts illustrated the characteristics of the new materials and two important applications. Mr A. C. Barber of the Imperial Metal Industries Limited and Mr M. T. Taylor of the Central Electricity Research Laboratories, Leatherhead, showed composite conductors for large superconducting electromagnets developed jointly by I.M.I. Limited and C.E.R.L. in which Niobium-titanium superconductor is co-processed with copper. Samples were shown of conductors designed for individual applications by varying the number and diameter of superconducting filaments, the proportion of copper and the overall conductor cross-section.

XUV Absorption Spectra of Carbon Ions

1988 ◽  
Vol 102 ◽  
pp. 71-73
Author(s):  
E. Jannitti ◽  
P. Nicolosi ◽  
G. Tondello
Keyword(s):  
Absorption Spectra ◽  
Cross Section ◽  
Theoretical Calculations ◽  
Photoionization Cross Section ◽  
Carbon Ions

AbstractThe photoabsorption spectra of the carbon ions have been obtained by using two laser-produced plasmas. The photoionization cross-section of the CV has been absolutely measured and the value at threshold, σ=(4.7±0.5) × 10−19cm2, as well as its behaviour at higher energies agrees quite well with the theoretical calculations.

Elastic Scattering in Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 252-253
Author(s):  
J. Langmore ◽  
M. Isaacson ◽  
J. Wall ◽  
A. V. Crewe
Keyword(s):  
Electron Microscopy ◽  
Elastic Scattering ◽  
Cross Section ◽  
Quantum Noise ◽  
Dark Field ◽  
Elastic Cross Section ◽  
Biological Molecules ◽  
Dark Field Microscopy ◽  
Field Systems ◽  
Effects Of Radiation

High resolution dark field microscopy is becoming an important tool for the investigation of unstained and specifically stained biological molecules. Of primary consideration to the microscopist is the interpretation of image Intensities and the effects of radiation damage to the specimen. Ignoring inelastic scattering, the image intensity is directly related to the collected elastic scattering cross section, σɳ, which is the product of the total elastic cross section, σ and the eficiency of the microscope system at imaging these electrons, η. The number of potentially bond damaging events resulting from the beam exposure required to reduce the effect of quantum noise in the image to a given level is proportional to 1/η. We wish to compare η in three dark field systems.

Sign in / Sign up

Export Citation Format

Share Document