Projectile Driving Band Interactions With Gun Barrels

2006 ◽  
Vol 128 (2) ◽  
pp. 273-278 ◽  
Author(s):  
Tony D. Andrews
Keyword(s):  
Maximum Charge ◽  
Gun Barrel ◽  
Potential Problems ◽  
Charge Zone ◽  
Pressure Changes ◽  
Forward Part ◽  
Very High ◽  
High Band ◽  
Good Agreement ◽  
External Strain

This paper discusses results from a series of trials carried out to determine the effect of the projectile driving band on the stress applied to a 155mm gun barrel during firing. The interference between the driving band and gun barrel can apply significant loads to the barrel and, in extreme cases, lead to premature cracking and failure of the barrel. Strain gage data from firing trials has been used to characterize the external strain from firing different projectiles and charges to identify potential problems and provide information for fatigue analysis. Very high band strains were routinely measured under “oiled bore” conditions, i.e., after barrel cleaning and also during the first one to three rounds of a serial following a long pause in firing, such as at the start of a day’s firing. In general, the strain associated with the driving band was seen to decrease with increased charge zone, barrel wear, and, at higher charge zones, distance along the barrel. In the majority of tests fired at maximum charge, there was no strain peak associated with the driving band in the forward part of the barrel. In conjunction with these experimental observations, a laboratory study has been carried out on the effect of a narrow pressure band on the deformation of a thick-walled tube. An apparatus was constructed in order to pressurize a known length of a smooth-bore cylinder. Sealing width at the edges of the band was minimized to reduce edge effects, and an oversize pressurized “cap” was used to ensure that the bandwidth remained constant during the experiments. Spacer disks were used to vary the bandwidth and also to adjust the cylinder position relative to the band. Measured external strains on the tubes were compared to calculations based on analytical solutions for step pressure changes and are shown to be in good agreement.

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

scholarly journals Separate Universe calibration of the dependence of halo bias on cosmic web anisotropy

2020 ◽  
Vol 499 (3) ◽  
pp. 4418-4431 ◽  
Author(s):  
Sujatha Ramakrishnan ◽  
Aseem Paranjape
Keyword(s):  
Dark Matter ◽  
High Precision ◽  
Gaussian Distribution ◽  
Initial Perturbation ◽  
Analytical Framework ◽  
Web Environment ◽  
Wide Range ◽  
Galaxy Assembly ◽  
Very High ◽  
Good Agreement

ABSTRACT We use the Separate Universe technique to calibrate the dependence of linear and quadratic halo bias b1 and b2 on the local cosmic web environment of dark matter haloes. We do this by measuring the response of halo abundances at fixed mass and cosmic web tidal anisotropy α to an infinite wavelength initial perturbation. We augment our measurements with an analytical framework developed in earlier work that exploits the near-lognormal shape of the distribution of α and results in very high precision calibrations. We present convenient fitting functions for the dependence of b1 and b2 on α over a wide range of halo mass for redshifts 0 ≤ z ≤ 1. Our calibration of b2(α) is the first demonstration to date of the dependence of non-linear bias on the local web environment. Motivated by previous results that showed that α is the primary indicator of halo assembly bias for a number of halo properties beyond halo mass, we then extend our analytical framework to accommodate the dependence of b1 and b2 on any such secondary property that has, or can be monotonically transformed to have, a Gaussian distribution. We demonstrate this technique for the specific case of halo concentration, finding good agreement with previous results. Our calibrations will be useful for a variety of halo model analyses focusing on galaxy assembly bias, as well as analytical forecasts of the potential for using α as a segregating variable in multitracer analyses.

scholarly journals The high Arctic in extreme winters: vortex, temperature, and MLS and ACE-FTS trace gas evolution

2008 ◽  
Vol 8 (3) ◽  
pp. 505-522 ◽  
Author(s):  
G. L. Manney ◽  
W. H. Daffer ◽  
K. B. Strawbridge ◽  
K. A. Walker ◽  
C. D. Boone ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Lower Stratosphere ◽  
High Arctic ◽  
Trace Gas ◽  
Satellite Measurements ◽  
Broadband Emission ◽  
Gas Measurements ◽  
Chemistry Experiment ◽  
Very High ◽  
Good Agreement

Abstract. The first three Arctic winters of the ACE mission represented two extremes of winter variability: Stratospheric sudden warmings (SSWs) in 2004 and 2006 were among the strongest, most prolonged on record; 2005 was a record cold winter. Canadian Arctic Atmospheric Chemistry Experiment (ACE) Validation Campaigns were conducted at Eureka (80° N, 86° W) during each of these winters. New satellite measurements from ACE-Fourier Transform Spectrometer (ACE-FTS), Sounding of the Atmosphere using Broadband Emission Radiometry (SABER), and Aura Microwave Limb Sounder (MLS), along with meteorological analyses and Eureka lidar temperatures, are used to detail the meteorology in these winters, to demonstrate its influence on transport, and to provide a context for interpretation of ACE-FTS and validation campaign observations. During the 2004 and 2006 SSWs, the vortex broke down throughout the stratosphere, reformed quickly in the upper stratosphere, and remained weak in the middle and lower stratosphere. The stratopause reformed at very high altitude, near 75 km. ACE measurements covered both vortex and extra-vortex conditions in each winter, except in late-February through mid-March 2004 and 2006, when the strong, pole-centered vortex that reformed after the SSWs resulted in ACE sampling only inside the vortex in the middle through upper stratosphere. The 2004 and 2006 Eureka campaigns were during the recovery from the SSWs, with the redeveloping vortex over Eureka. 2005 was the coldest winter on record in the lower stratosphere, but with an early final warming in mid-March. The vortex was over Eureka at the start of the 2005 campaign, but moved away as it broke up. Disparate temperature profile structure and vortex evolution resulted in much lower (higher) temperatures in the upper (lower) stratosphere in 2004 and 2006 than in 2005. Satellite temperatures agree well with lidar data up to 50–60 km, and ACE-FTS, MLS and SABER show good agreement in high-latitude temperatures throughout the winters. Consistent with a strong, cold upper stratospheric vortex and enhanced radiative cooling after the SSWs, MLS and ACE-FTS trace gas measurements show strongly enhanced descent in the upper stratospheric vortex in late January through March 2006 compared to that in 2005.

Competitive reactions in the irradiation of anthracene + cyclohexane solutions

1959 ◽  
Vol 249 (1256) ◽  
pp. 51-64 ◽  
Keyword(s):  
Radiation Intensity ◽  
Quantitative Agreement ◽  
Radical Scavenger ◽  
Organic Systems ◽  
Low Concentrations ◽  
Radiation Induced ◽  
Experimental Values ◽  
Very High ◽  
Intensity Radiation ◽  
Good Agreement

Anthracene acts as a radical scavenger when present at low concentrations in irradiated hydrocarbons. A study has been made of the effect of radiation intensity and anthracene concentration on G( — A) , the number of anthracene molecules lost per 100 eV of energy absorbed. A theoretical calculation is made of the dependence of G( — A) on radiation intensity 1 and anthracene concentration ( A ), assuming that radiation-induced radicals (R.) are formed at random, and can either disappear by direct combination with one another, or with the anthracene to give RAR or RAAR bridges, or possibly some form of stabilized RA molecules. This theory is in good agreement with the experimental values of G( — A) measured at various low radiation intensities and anthracene concentrations. From the comparison estimates of the reactivity constants are derived. With very high intensity radiation quantitative agreement is less satisfactory, due to the non-steady conditions prevailing in a pulsed beam. The results obtained are compared with previous work on anthracene + hexane and iodine + cyclo hexane mixtures, in which the effect of radiation intensity was not investigated. The results reported here are of interest to the study of reaction kinetics in irradiated organic systems.

Calculation of Punch Force and Maximum Pressure for Tube Extrusion

2000 ◽  
Author(s):  
S.-H. Zhang ◽  
Y.-L. Shang
Keyword(s):  
Upper Bound ◽  
Physical Modeling ◽  
Steel Tube ◽  
Experimental Results ◽  
Maximum Pressure ◽  
Punch Force ◽  
Tube Extrusion ◽  
Tooling System ◽  
Very High ◽  
Good Agreement

Abstract Punch force and maximum pressure for tube extrusion can be predicted with an upper bound theory-based program POLSK. Experiments of steel tube extrusion and wax physical modeling were performed. The punch force and the maximum pressure values were obtained. Comparisons were made among the experimental results, physical modeling results and upper bound predictions. It was found that a medium extrusion coefficient causes the lowest pressure on the tooling system, very low and very high extrusion coefficients can both cause very high pressure. It is proved that the upper bound predictions are in good agreement with the experimental results and the upper bound program is suitable for use of steel tube extrusion design.

scholarly journals New Coefficients of the Minority Carrier Lifetime and Bandgap Narrowing Models in the Transparent Emitter of Thin Film Silicon Solar Cells

2003 ◽  
Vol 26 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. Zerga ◽  
M. Benosman ◽  
F. Dujardin ◽  
B. Benyoucef ◽  
J-P. Charles
Keyword(s):  
Silicon Solar Cell ◽  
Minority Carrier ◽  
Minority Carrier Lifetime ◽  
Bandgap Narrowing ◽  
Heavy Doping ◽  
High Level ◽  
Band Gap Narrowing ◽  
Very High ◽  
Minority Carriers ◽  
Good Agreement

In this study we have determined new coefficients for the physical model describing the band-gap narrowing and the minority carriers lifetime. This was accomplished according to the doping level of the thin emitter. This model allows us to take into account both the effects of the heavy doping and the majority carrier degeneration for the very high level of doping. The results we obtain by the corrected model are in good agreement with those reported in the literature and in different experiments. They show us the possibility of accurately evaluating the performances for then+psilicon solar cell. This model is then used to introduce a new concept for the thin layer emitter, called transparent emitter.

scholarly journals Low-Profile Spidron Fractal Dipole Antenna with a Ferrite-Loaded Artificial Magnetic Conductor for Manpack Applications

2020 ◽  
Vol 10 (24) ◽  
pp. 8843
Author(s):  
Oh Heon Kwon ◽  
Keum Cheol Hwang
Keyword(s):  
High Frequency ◽  
Dipole Antenna ◽  
Magnetic Conductor ◽  
Very High Frequency ◽  
Artificial Magnetic Conductor ◽  
Received Power ◽  
Low Profile ◽  
Profile Characteristics ◽  
Very High ◽  
Good Agreement

In this paper, a Spidron fractal dipole antenna with a ferrite-loaded artificial magnetic conductor (AMC) is presented. By applying ferrite composed of nickel–zinc with a high permeability value, a compact AMC that operates in the broadband frequency range within the high-frequency/very-high-frequency/ultra-high-frequency (HF/VHF/UHF) bands was designed. A Spidron fractal-shaped dipole antenna with a quasi-self-complementary structure was designed and combined with a miniaturized ferrite-loaded AMC. This allowed the designed AMC-integrated dipole antenna to operate in a wide frequency band, covering the HF/VHF/UHF bands, with low-profile characteristics. A prototype of the proposed Spidron fractal dipole antenna with the AMC was manufactured and measured and found to meet low VSWR (voltage standing wave radios) specifications of <3.5 within the 20–500 MHz bandwidth range. The simulated and measured results are in good agreement. The size of the Spidron fractal dipole antenna with the AMC is 0.03×0.026×0.001λ3 relative to the wavelength of the lowest operating frequency. The received power of the Spidron fractal dipole antenna with the AMC was also measured when it was applied to relatively small applications, such as a manpack in this case.

New automated dye-binding method for serum albumin determination with bromcresol purple.

1978 ◽  
Vol 24 (1) ◽  
pp. 80-86 ◽  
Author(s):  
A E Pinnell ◽  
B E Northam
Keyword(s):  
Serum Albumin ◽  
Albumin Concentration ◽  
High Concentration ◽  
Serum Globulin ◽  
The Poor ◽  
Dye Binding ◽  
Free Serum ◽  
Very High ◽  
Continuous Flow Method ◽  
Good Agreement

Abstract We describe a new automated dye-binding method for serum albumin determination with bromcresol purple (BCP) that has several advantages over an existing bromcresol green (BCG) method. The continuous-flow method is sensitive, linear, and precise, with negligible sample interaction at an analytical rate of 60 samples per hour. Unlike BCG, BCP did not react with an albumin-free serum globulin preparation or pure human transferrin solutions. Reaction with serum was instantaneous; in contrast, BCG exhibits a slow nonspecific reaction with some specimens. The specificity of BCP was demonstrated by good agreement with results of "rocket" immunoelectrophoresis (EIA) where y(BCP) = 0.95X(EIA) + 1.72. The BCG method overestimated serum albumin concentration where y(BCG) = 1.01X(EIA) + 6.77. Precipitation, which affects the BCG method, was not observed with BCP. Blank corrections were negligible, salicylate did not interfere, and bilirubin affected the method only if present in very high concentration. The method offers a solution to the poor accuracy of existing BCG methods while retaining many of their desirable features.

scholarly journals Data Analysis and Calibration of Radiocarbon Dating Results from the Cemetery of the Marquises of Jin

Radiocarbon ◽  
2001 ◽  
Vol 43 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Xiangyang Lu ◽  
Zhiyu Guo ◽  
Hongji Ma ◽  
Sixun Yuan ◽  
Xiaohong Wu
Keyword(s):  
Data Analysis ◽  
High Precision ◽  
Radiocarbon Dating ◽  
Careful Analysis ◽  
Historical Record ◽  
Calibration Result ◽  
Special Part ◽  
Peking University ◽  
Very High ◽  
Good Agreement

The chronology study of the cemetery of Marquises of Jin is valuable to improving the chronological table of Marquis of Jin family. It is also helpful for improving the chronological table of the Zhou Dynasty. The samples were measured at Peking University (PKUAMS). We also made an interlaboratory check with Isotrace to ensure the accuracy. By careful analysis of archaeological information, we built different models and calibrated by OxCal. The calibration results, both sampling contexts and estimations, are in very good agreement with the historical record. Because the dates of some events correspond to the special part of the curve, the calibration gets very high precision. The calibration result of tomb M93 suggests that its host is Marquis Shangshu instead of Marquis Wen.

The Effects of Geometrical Factors on the Step-Up Ratio in Piezoelectric Transformer

2007 ◽  
Vol 539-543 ◽  
pp. 3319-3325
Author(s):  
Man Soon Yoon ◽  
T.S. Yoon ◽  
J.R. Kim ◽  
Y.G. Choi ◽  
Soon Chul Ur
Keyword(s):  
Element Model ◽  
Vibration Modes ◽  
Electromechanical Properties ◽  
Piezoelectric Transformer ◽  
Voltage Step ◽  
3 Dimensional ◽  
Geometrical Factors ◽  
The Finite Element Model ◽  
Very High ◽  
Good Agreement

The electromechanical properties of a newly proposed 3-dimensional piezoelectric transformer have been investigated. Especially, the effects of 3-dimensional geometry on the maximum tip displacement were carefully investigated. As a result, it was found that the maximum strain of the 3-dimensional piezoelectric device was significantly enhanced up to 4.5 times higher than that of a disk shape device. This data were in good agreement with the finite element model analysis of strains and vibration modes. Moreover, a very high voltage step-up ratio of 290 (10 times higher than the Rosen type), sustaining efficiency more than 96%, were achieved.

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