Component Diagrams Research Articles

A Gravity-Feed System for Controlling pH, in Flow-Through Aquatic Toxicity Experiments

A standard pH control system was modified to provide more reliable and precise control for acute and chronic aquatic toxicity tests using flow-through exposures. System components were developed which reduced both the lag time associated with standard control systems, and the loss of control function which occurs during power failure. These modifications produced a system which exhibited little deviation around the pH setpoint during acute experiments and may be amenable to longer-term studies in which the likelihood of power failure is high. Diagrams of system components are included, along with an example application of the system.

Computer simulation of a combined cycle power plant

This paper presents the simulation procedure developed to predict the performance of a combined cycle power plant from given performance characteristics of its main components. In order that the procedure could be validated, the simulation technique has been applied to a typical combined cycle power plant (having a dual pressure bottoming cycle) manufactured by a prominent company. The characteristics of the standard equipment like the air compressor, steam and gas turbines, various pumps, etc. have been taken from the manufacturer's catalogues and converted into appropriate equations based on theoretical understanding. The performance of various heat exchangers (like economizers, superheaters, evaporators, etc.) has been determined by using the effectiveness concept after evaluating the overall heat transfer coefficient by using appropriate correlations from literature. The strategy of system simulation is obtained by judiciously interlinking the information flow diagrams of various components and thus the task is finally reduced to that of solving nine non-linear equations for nine variables. The predicted performance of the system is seen to be in good agreement with in good agreement with its rated performance.

Initial investigation of site and topographic effects at Robinwood Ridge, California

Abstract Following the 1989 Loma Prieta earthquake, a dense array of seven digitally recorded, three-component seismograph stations was deployed on Robinwood Ridge 7.3 km northwest of the epicenter. The purpose of this array was to investigate the cause of high levels of structural damage and ground cracking observed on the ridge crest. Aftershocks recorded by the array allow a comparison of ground motion up the slope of the ridge from the base to the crest. The data present an extremely complicated pattern of ground motion that demonstrates the importance of the three-dimensionality of the problem. Slowness analysis of P wave trains show initial arrivals propagating away from the source with small angles of incidence and large apparent velocities, consistent with direct arrivals. After 0.5 sec, propagation azimuths become more random and apparent velocities drop, indicating nearly horizontal wave propagation and multiply reflected and diffracted phases within the ridge. Slowness analysis and particle motion diagrams of horizontal components of motion show dramatic variations in ground motion with changes in azimuth of the source and a complicated interaction between body waves and Rayleigh and Love waves. Results suggest that the larger amplitude, more coherent arrivals at the array stations favor a propagation direction parallel to the ridge axis. An amplification factor of from 1.5 to 4.5 is seen for frequencies from 1.0 to 3.0 Hz with wavelengths comparable to the base of the ridge, part of which may be caused by local site effects and part by topographic amplification. In addition, amplifications of up to a factor of 5 are seen at higher frequencies and are attributed to local site effects. These effects are most notable from 4 to 8 Hz on the vertical components, and from 6 to 9 Hz on the horizontal components. The entire Robinwood Ridge area may also have been situated in a region of heightened mainshock ground motion due to source directivity and radiation pattern effects.

Big graphics and little screens: designing graphical displays for maintenance tasks

Traditional maintenance information includes large graphical drawings that are difficult to portray on the small screens of computer-based maintenance information systems. The research described investigates the design of graphical displays using display abstraction and aggregation as design parameters. A display's aggregation level reflects the field of view of a display, such as component, assembly, or system-level diagrams. A display's abstraction level reflects the representation contained in a diagram, such as a component's form, function, or purpose in an assembly. The results from two experiments with experienced maintenance personnel are presented. Usage of the display abstraction levels was found to vary with both the nature of the maintenance task and the experience level of the maintenance personnel. Usage of the display aggregation levels was found to change as task performance proceeded. The results support the application of these concepts to computer-based maintenance information systems. >

FORMATION AND APPLICATIONS OF MULTIPLE EMULSIONS

Abstract Multiple emulsions, especially water-in-oil-in-water (W/O/W) type systems, have potential applications for the formulation and processing of foods, drugs, cosmetics, etc, as each dispersed globule in this type of emulsions consists of liquid compartments separated from the same liquid suspending medium by a thin layer of another immiscible liquid components. This article reviews a series of fundamental works on the formation and dispersion state of multiple emulsion systems and integrates advances made in the area of colloid science so as to obtain further insights into the formulation of W/O/W emulsions. The contents are divided into three sections: methods for preparing multiple emulsions in view of the phase diagram of mixed components, dynamic aspects of oil layer in W/O/W emulsions, and stability of this type of emulsions.

Macroemulsion science - A background for understandings of the dispersion state of biological components.

This paper reviews briefly the works on dispersion state of a variety of macroemulsions and integrates advances made in the areas of colloid science so as to obtain futher insights into the formulation of non-equilibrium systems. The contents are divided into three sections: concept of macroemulsion state, type of emulsions in view of the phase diagram of mixed components, and formation of multiple emulsions.

Particle Size Distributions and Particle Size Alterations in Microemulsions

Several component diagrams for different alcohols as cosurfactants and potassium oleate as the surfactant were investigated. Between the regions of the water-in-oil microemulsion and the micellar solution (reverse micelles), and diagrams showed a zone of instability which was determined by particle size analysis by means of photon correlation spectroscopy (PCS). The poly-dispersity of the internal phase was determined at the instant of microemulsion formation and after fixed intervals of storage. At the edge of the microemulsion region, a rapid increase in particle size due to coalescence followed by breaking was observed. If a slow transition toward the region of solubilization could be seen by a slow decrease of the droplet size, coalescence was observed after storage. In the middle of the microemulsion region, the particle radius, however, was almost constant for a long interval. The velocity of the microemulsion formation depended on the alcohol used. In some cases a very fast formation (milliseconds) was observed; in others, macroemulsions were formed which became transparent within a few hours or days. PCS was used to follow the dynamic process of formation and breaking of such systems with droplet diameters of 5–200nm by obtaining the mean hydrodynamic diameters. Distribution curves were calculated by the Laplace transform of the correlation function. The practicability of the method was demonstrated with mono- and polydispersed latex suspensions and microemulsions.

The minimum scan range and detector aperture as a function of specimen size in X-ray diffractometry

The theoretical functional relationship of scan range and detector aperture to (spherical) crystal size in respect of scattering angle θ in X-ray diffractometry for different scan modes is not clearly defined in the literature. It is shown that it is necessary to examine separately the factors determining the angular apertures of the beam incident on the crystal and of the beam diffracted from the crystal, and then the appropriate relationship is derived for a point source and a small spherical crystal for the ω-scan mode. The required aperture is shown to be 2accos2θ, where ac is the diameter of the crystal. Using (Δω, Δ2θ(s)) component diagrams [Mathieson, (1983). Aust. J. Phys. 36, 79–83], the corresponding results are derived for the ω/θ- and ω/2θ-scan modes and the three results are shown to be consistent with the earlier deductions which yielded cos2θ for the ω-scan mode but not with those which yielded cos θ.

Kerogen maturation and petroleum genesis

KEROGEN, the non-extractable organic matter in recent and ancient sediments, has been studied extensively for its importance in petroleum genesis. However, the chemistry of kerogen is not clear because of its highly-polymerised and complicated structure. Elemental analysis, especially of carbon, hydrogen and oxygen, is the most fundamental method of characterising kerogens, and a C–H–O diagram can be effectively used for their classification1–4. The progressive changes of chemical composition of kerogens with depth of sediments which take place release CO2, H2O, and liquid and gaseous hydrocarbons. This process kerogen maturation2, increases the carbon content of kerogen, and eventually forms graphite. Although the carbon content of kerogen increases as CO2 and/or H2O is released, the generation of hydrocarbons will reduce the carbon content. Therefore, it is important to examine the compositional change of kerogens as they release CO2, H2O and hydrocarbons, respectively. This paper discusses kerogen maturation in relation to petroleum genesis on a three component (C, H and O) diagram.

A Numerical Taxonomic Study of the Avocado (Persea americana Mill.)1

Abstract Principal components and cluster analyses, based on 67 characters, were applied to 38 cultivars, which collectively exemplified the 3 races of avocado and their racial hybrids. Diagrams constructed from principal component analysis clearly showed the phenetic diversity of the 3 races and their racial hybrids. Correlation and distance phenograms from cluster analyses did not show overall phenetic diversity as well as principal component diagrams. The phenograms were most useful, however, in showing phenetic similarities among closely related cultivars, which were obscure in principal component analysis. The 2 methods are, thus, complementary, and both methods are recommended in studying patterns of variation with species such as avocado.