A laboratory study in radioactivity designed to examine reaction to unexpected experimental results

1959 ◽  
Vol 43 (2) ◽  
pp. 153-155
Author(s):  
Walter S. Lundahl
Keyword(s):  
Laboratory Study ◽  
Experimental Results

Laboratory Study of Cylindrical Sedimentation Traps

1979 ◽  
Vol 36 (10) ◽  
pp. 1288-1291 ◽  
Author(s):  
Y. L. Lau
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Key Words ◽  
Laboratory Study ◽  
Fluid Motion ◽  
Bottom Layer ◽  
Experimental Results ◽  
Dimensionless Variables ◽  
Different Diameters ◽  
Neutrally Buoyant

Observations of the motion of fluid particles in cylindrical sedimentation traps showed that with an increase of the aspect ratio, there is also an increase in the Reynolds number below which neutrally buoyant droplets that were placed near the floor of the trap would remain in the bottom layer. The dependence of the fluid motion on these two dimensionless variables was demonstrated using traps of different diameters. For single cylindrical traps, the experimental results can be used to obtain estimates of the Reynolds number below which resuspension of settled material would not be expected to occur. Key words: sedimentation trap, aspect ratio, Reynolds number, limnological instrument

Hydraulic performance of sewer pipes with deposited sediments

2008 ◽  
Vol 57 (11) ◽  
pp. 1743-1748 ◽  
Author(s):  
Robert Banasiak
Keyword(s):  
Discharge Capacity ◽  
Laboratory Study ◽  
Hydraulic Performance ◽  
Experimental Results ◽  
Cohesive Sediments ◽  
Sewer Pipes ◽  
Friction Characteristics ◽  
Study Results ◽  
Bed Forms ◽  
Sediment Deposit

This paper investigates in-sewer sediment deposit behaviour and its influence on the hydraulic performance of sewer pipes. This evaluation is based on experimental results regarding the mobility of non-cohesive and partly cohesive deposits in a partially full circular pipe. The focus of these tests is on the development of bed forms and friction characteristics. In particular, it is investigated to what extent the bed forms from the non-cohesive and (partly) cohesive sediments affect a sewer's discharge capacity. Based on the laboratory study results and on the existing criteria for sewer design, a generic assessment of a sewer's hydraulic performance is made. The relative discharge factor for a pipe with sediment deposit is analysed in terms of the thickness and roughness of the deposit.

A laboratory study of preferential predation by the newt Notophthalmus v. viridescens

1980 ◽  
Vol 58 (9) ◽  
pp. 1712-1717 ◽  
Author(s):  
Etienne N. Attar ◽  
Edward J. Maly
Keyword(s):  
Relative Density ◽  
Laboratory Study ◽  
Prey Density ◽  
Activity Patterns ◽  
Relative Proportion ◽  
Experimental Results ◽  
Turbid Water ◽  
Total Abundance ◽  
Hunting Behavior ◽  
Reduced Temperature

Experiments were performed to determine if the newt Notophthalmus v. viridescens preferred the amphipod Hyalella over the cladoceran Daphnia under laboratory conditions and how temperature, relative proportion of prey, and total abundance of prey affects prey preference. Experiments demonstrate that Hyalella is the preferred prey at high prey densities but that Daphnia is preferred at low prey densities. Relative density of prey does not affect the preference for Hyalella at high prey density, but reduced temperature eliminates the preference for Hyalella at these high densities. Turbid water reduces the feeding rate.The experimental results can be attributed to hunting behavior of the newt and to size and activity patterns of the prey. The results suggest that the newt is an opportunistic feeder and that prey movement affects numbers of prey eaten.

A Simple Artificial Solar Cell for Laboratory Study

2014 ◽  
Vol 931-932 ◽  
pp. 957-961
Author(s):  
Chonlatee Photong
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Laboratory Study ◽  
Current Source ◽  
Electric Properties ◽  
Experimental Results ◽  
Artificial Cells ◽  
Test Environment ◽  
Dc Current ◽  
Alternative Structure

Using actual solar cells for laboratory study may encounter some problems related to uncontrollable test environment and large operating area. Artificial solar cells which can provide electric properties similar to the actual cells but with controllable test features and less operating area therefore are usually used instead. However, most artificial solar cells relatively have high cost and complex. This paper presents an alternative structure of artificial cells. The proposed artificial solar cell consists of a DC current source, a string of series diodes, a diode and two resistors. As only few elements are used for the cell, the proposed cell can achieve simple configuration, small in size, light in weight and inexpensive. The experimental results show that the proposed cell can generate correct electrical outputs with the error less than 5% compared to the actual cell.

Bohr’s Derivation of the Rydberg Formula

2020 ◽  
pp. 55-72
Author(s):  
Jim Baggott
Keyword(s):  
Angular Momentum ◽  
Internal Structure ◽  
Orbital Angular Momentum ◽  
Laboratory Study ◽  
Atomic Structure ◽  
Experimental Results ◽  
Central Nucleus ◽  
Rydberg Constant ◽  
Nuclear Atom ◽  
Fundamental Physical

Atoms evolved from hypothetical entities into the objects of detailed laboratory study. The discovery of the negatively charged electron by Thomson in 1897 implied that atoms, indivisible for more than 2000 years, now had to be recognized as having some kind of internal structure. In 1911 Rutherford interpreted the latest experimental results in terms of a ‘nuclear atom’, in which most of the atom’s mass is concentrated in a small central nucleus, surrounded by electrons which account for much of the volume. In 1913, Bohr presented a theory of atomic structure which combined a model of classical mechanical ‘orbits’ and transitions between these orbits governed by quantum rules. Although he made some unjustified (and incorrect) assuptions regarding the quantization of orbital angular momentum, he successfully predicted the Rydberg formula and showed that the Rydberg constant is a composite of fundamental physical constants.

Diagnostics of Gold Laser Plasmas

1988 ◽  
Vol 102 ◽  
pp. 357-360
Author(s):  
J.C. Gauthier ◽  
J.P. Geindre ◽  
P. Monier ◽  
C. Chenais-Popovics ◽  
N. Tragin ◽  
...  
Keyword(s):  
Experimental Results ◽  
Pure Gold ◽  
Electronic Temperature ◽  
X Ray ◽  
Laser Plasmas ◽  
Collisional Radiative Model ◽  
Radiative Model

AbstractIn order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.

Observation of Phase Contrast Images in STEM and CTEM Modes by Using 100 kV Field Emission Electron Gun

1974 ◽  
Vol 32 ◽  
pp. 390-391
Author(s):  
Y. Harada ◽  
T. Goto ◽  
H. Koike ◽  
T. Someya
Keyword(s):  
Field Emission ◽  
Phase Contrast ◽  
Image Formation ◽  
Fresnel Diffraction ◽  
Experimental Results ◽  
Electron Gun ◽  
Scanning Microscopy ◽  
Emission Electron ◽  
Lattice Images

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

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