Observation and Measurement

A quantitative description of sea state can only be provided with statistically established parameters. To estimate a characteristic sea state height, an observer has to average as many individual waves as possible. Because of the sparse instrument measurements in almost all sea areas, the visual estimate of the wave height, the wave period, and the direction from which the waves come, is still of great importance. 

In addition to meteorological data, many ships also report visual wave observations to the weather services for these reports defined rules are available (WMO, 1996). All over the world, these data are used for climatological analysis (see Section 7.1.5). However, the reports from ships are focused mainly on the much-traveled routes. The estimates of the wave heights are more reliable than those of the observed wave periods. 

With the exception of measurements from satellites, which permit global coverage, for technical reasons, instrument measurements are performed mostly near the coast or near an offshore platform. 

In addition to moored measuring buoys, instruments for underwater use (such as pressure sensors and acoustic current meters) as well as remote sensing technology (such as radar instruments) that are employed from ships, aircraft, and satellites are available. 

Very often buoys are used that move with the surface. They have a special elastic mooring, so that the buoy is able to follow the orbital motion of the wave as freely as possible. These measuring buoys contain at least one acceleration sensor for the vertical component. In direction-measuring buoys, the position of the case relative to the horizontal line and to the north has to be determined by additional sensors. The significant wave height and the characteristic periods are then calculated from the variance spectrum of the vertical displacement, and the directional information results from a cross spectral analysis of all components of the buoy movement. A comprehensive description of the measuring instruments and the statistical analysis methods was given by Tucker (1991). 

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It is difficult to determine the cross-sectional area of a fiber. Direct observation and measurement of a cross section under a microscope is the most accurate method (15). This is a destmctive test that does not allow subsequent study of fiber mechanical properties, and is slow and tedious. Also, it does not take into account any variations in the cross-sectional area along the fiber length. Measurement of fiber diameters from microscopic observations of longitudinal views is somewhat easier, but the eUipticity of the cross section in certain fibers can lead to serious errors. 

The effect can be observed and measured by using two similar thermometers (Figure 23.3), one of which has its bulb enclosed in a wet wick. The drier the air passing over them, the greater will be the rate of evaporation from the wick and the greater the difference between the two readings. In the case of air at 25°C, 50% saturation, the difference will be about 6.5 K. The measurements are termed the dry bulb and wet bulb temperatures, and the difference the wet bulb dqrression. 

The title, CHEMISTRY—An Experimental Science, states the theme of this one year course. A clear and valid picture of the steps by which scientists proceed is carefully presented and repeatedly used. Observations and measurements lead to the development of unifying principles... 

Microscopy. A broad definition of microscopy is the observation and measurement of optical parameters with any instrument that uses energy sources such as photons, electrons or X-rays to... 

Instrumentation for experimental observation and measurement is paramount in microstmcture-related research. One reason that surfaces, interfaces, and more complicated microstructures are a frontier of chemical engineering and processing research is that modem science has recently spawned a number of microstractural probes of unprecedented resolution and utility. For the first time, we have the proper tools to attack the molecular and chemical basis of microstructures. 

The STEM Is Ideally suited for the characterization of these materials, because one Is normally measuring high atomic number elements In low atomic number metal oxide matrices, thus facilitating favorable contrast effects for observation of dispersed metal crystallites due to diffraction and elastic scattering of electrons as a function of Z number. The ability to observe and measure areas 2 nm In size In real time makes analysis of many metal particles relatively rapid and convenient. As with all techniques, limitations are encountered. Information such as metal surface areas, oxidation states of elements, chemical reactivity, etc., are often desired. Consequently, additional Input from other characterization techniques should be sought to complement the STEM data. 

Starting in the 1950s, electrochemical principles have been employed in the development of new technical means for the acquisihon, measurement, storage, transformation, and transfer of various types of informahon. By now many electrochemical devices have been developed for such purposes and are used to build automated systems for the control of production processes, for the automation of geophysical observations and measurements, and for many other purposes. This field, intermediate between electrochemistry, informatics, and electronics, is also known as chemotronics. 

Based on visual observations and measurements in various basic tests, observed impressions are recorded in sketches as a summary. These sketches can be justified... 

The fourth method, astronomical measurement, is (like the Doppler method) based on the observation and measurement of tiny motions of a star which are due to the mass(es) of the orbiting planet(s). A primary goal of the Space Interferometry Mission (SIM) is the discovery of planets similar to Earth, which orbit around stars like the sun. The SIM is due to start in 2009, and the measurements carried out will increase the accuracy of determinations of distances of stars in our galaxy several hundred times. Exact information can be found in the catalogue which forms part... 

In addition to relaxing the fabrication tolerances, the mixed Bragg order implementation induces a coherent diffraction component in the vertical direction23. Although this mechanism reduces the overall Q of the cavity, it facilitates the observation and measurement of the resonator emission. 

Collection Techniques. The simplest mechanical method for normal liquid droplets is the slide collection slide sampling) or impression method. This method was extensively used three decades ago, and has been rarely employed since then. In this method, when the slide is exposed to a spray, droplets impinging on it make impressions. The impressions are then observed and measured usually using a Quantimet image analyzer, although a microscope fitted with a traversing scale may be used for the measurement. The measured data are subsequently converted to actual droplet sizes based on a correction factor proposed by May.[659]... 

Optical isomerism is shown by compounds which are capable of rotating the plane of polarized light. The phenomenon is called optical activity and the substances possessing this property are called optically active substances. The optical activity is observed and measured by an instrument called polarimeter. ... 

Allow the plate to dry. Observe and measure Rf values, if possible, and identify the dyes in the cough syrups. 

Empirical Determined through observation and measurement rather than from theoretical principles. 

In roughly the past 100 years, though, some scientists have studied the paranormal and attempted to find scientific evidence for it. Psychic phenomena have proven difficult to observe and measure according to scientific standards. However, lack of scientific proof does not mean paranormal experiences do not happen. Courageous scientists are still looking for bridges between science and the supernatural. 

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