Composite Ground Research Articles

Wraparound patch resonators on a composite ground plane

The effects of a laminated ground plane on the resonant frequencies of wraparound patch resonators are studied. An integral equation is formulated in terms of the surface current on the patch. The laminated ground is modelled by a transition matrix in the spectral domain. Factors analysed include substrate thickness, substrate dielectric constant and laminate conductivity. Due to ohmic losses, more power loss is incurred for certain laminate conductivities.

Grinding technical questions of producing composite cement

A study has been made of the grinding of composite cements produced from clinker and two additional interground additives such as granulated blast-furnace slag, fly ash, trass and limestone. The grindabilities of composite cements depend on the grindability of the individual components. In case of intergrinding the interaction of the individual components plays a positive role. It has been stated that the particle size distribution of the ground products consisting of three components well follow the RRSB-distribution thus enabling this type of distribution to describe them. The particle size distribution of the “composite ground products” depends on their grindability and nature: the easier grindable interground additives promote the formation of wider particle size distribution. For approximately identical composition the fly ash and limestone have more widen particle size distribution than e.g. the trass. The presence of easier grindable components leads to wider particle size distribution and generally to lower mixing water demand. The water demand of composite cements with pozzolanic components is higher, especially in the presence of trass. In order to achieve standard strength the composite cements should be ground finer than the non-blended ones.

Scattering from an advanced composite cylindrical shell

With advanced composite materials forming parts of the aircraft skins, the study of their electromagnetic effects, such as the shielding properties of the composite shield, the antenna characteristics with the composite ground, and the scattering phenomena due to the composite scatterer, becomes an important issue in electromagnetic compatibility. A field analysis of scattering from an advanced composite cylindrical shell is given. Based on a theory used to describe the electromagnetic field in an anisotropic, multilayered, and lossy cylindrical shell structure, numerical results regarding monostatic and bistatic echo widths are presented for graphite/epoxy and boron/epoxy fiber-reinforced composite ones. Particularly, the parameters to influence the scattering characteristics, such as material property, cylinder radius, fiber orientation pattern, polarization (TE or TM), and frequency of incident wave are investigated in detail.

The South Frieze of the Parthenon: Problems in Arrangement

Almost without exception, recent studies of the Parthenon frieze have accepted W. B. Dinsmoor's arrangement of the south frieze. In his important contribution to our understanding of the problems of arrangement, however, the assignment of eight blocks to the victims of the south frieze is shown here to be based on an error. On technical and compositional grounds, this article largely reinstates the sequence first proposed by Adolph Michaelis, which employs only seven blocks, and goes on to consider the implications of this for the pedestrian sequence of the south frieze as a whole. The block that is released from the procession of victims may be allocated to a conjectured group of hydriaphoroi, balancing the four shown on the north frieze. Further, if it is accepted that the so-called pinax-bearers of the south frieze are, in fact, kithara-players like those on the north, then the long friezes of the Parthenon may be seen to parallel each other. Both consist, therefore, of a sequence of horsemen, chariots, elders, musicians, hydria-bearers, tray-bearers, and victims.

Direct observation of the anodic film on a sputter-deposited amorphous Al-W alloy

Abstract The formation of barrier-type anodic films on sputter-deposited amorphous Al-30W (at.%) alloy has been studied for the first time to elucidate ionic transport mechanisms across the film and associated interfaces. The film, grown with high Faradaic efficiency at 50 Am−2 to 150 V in aqueous 0.01 m ammonium pentaborate electrolyte at 293 K, comprises two main layers of relatively uniform composition and with flat, parallel and sharp interfaces: An outer layer, representing about 15% of the film thickness and composed of tungsten-free anodic alumina, and an inner layer containing both aluminium and tungsten in an amorphous structure based on groupings of Al2O3 and WO3. The two layers form as a consequence of the slower migration of tungsten species in the film compared with that of A13 + ions. The inner layer has, as expected on compositional grounds, a lower ionic resistivity than the outer layer; yet, contrary to predictions, film formation proceeds in a uniform manner, i.e. without current channelling. Aluminium and tungsten are incorporated into the film at the alloy-film interface in their alloying proportions within the limitations of the measurements.

Resonance properties of cylindrical rectangular patch with composite ground plane

Resonance characteristics of cylindrical-rectangular patch resonator in the presence of a laminated ground plane are studied. The laminated ground is modelled by a cascaded transition matrix in the spectral domain. An integral equation is formulated in terms of the surface current on the patch. Galerkin's method is then applied to solve for the resonance frequency. Factors analysed include substrate thickness, substrate dielectric constant, and laminate conductivity. It is found that certain laminate conductivities cause more power loss than the others. Replacing a perfect conductor ground by a laminated composite may shift the resonance frequency by 10%.

Effect of machining residual stresses on the repetitive impact behavior of silicon nitride

Silicon nitride is a candidate valve material for internal combustion engines. Its low density and attractive mechanical properties relative to conventional metallic alloys portend significant improvements in valve performance. The production of valves involves a significant amount of machining, especially grinding. Grinding of ceramic materials may result in surface and subsurface damage in the form of fracture or residual stresses which may affect impact behavior and, consequently, the behavior of silicon nitride ceramic materials as valves. The effects of residual stresses due to grinding on the impact wear behavior of one silicon nitride composition ground under various conditions have been investigated.

Shearing characteristics of composite ground and its application to stability analysis : Enoki, M; Yagi, N; yatabe, R; Ichimoto, E In: Deep Foundation Improvements: Design, Construction, and Testing (Papers to a Symposium presented at Las Vegas, 25 January 1990)P19–31. Publ Philadelphia: ASTM, 1991 (ASTM Special Technical Publication N1089)

Shearing characteristics of composite ground and its application to stability analysis : Enoki, M; Yagi, N; yatabe, R; Ichimoto, E In: Deep Foundation Improvements: Design, Construction, and Testing (Papers to a Symposium presented at Las Vegas, 25 January 1990)P19–31. Publ Philadelphia: ASTM, 1991 (ASTM Special Technical Publication N1089)

The Passion Prediction Passages and the Synoptic Problem: a Test Case

Some scholars continue to argue on compositional grounds that the Two-Document Hypothesis is to be preferred to the view that Luke first copied Matthew and that Mark then copied Matthew and Luke. The best way to answer such claims is to take a test case and discuss the matter in detail. It will be argued that the evidence indicates that there are serious difficulties with the view that Matthew and Luke independently copied Mark, a view essential to the Two-Document Hypothesis. It will further be argued that the view that Luke knew Matthew and that Mark used both Matthew and Luke is, in comparison to the Two-Document Hypothesis, the hypothesis to be preferred on compositional grounds.

Consolidation characteristics of composite ground : Enoki, M Proc Eighth Asian Regional Conference on Soil Mechanics and Foundation Engineering, Kyoto, 20–24 July 1987V1, P361–364. Publ Japan: Japanese Society for Soil Mechanics and Foundation Engineering, 1987

Consolidation characteristics of composite ground : Enoki, M Proc Eighth Asian Regional Conference on Soil Mechanics and Foundation Engineering, Kyoto, 20–24 July 1987V1, P361–364. Publ Japan: Japanese Society for Soil Mechanics and Foundation Engineering, 1987

Mechanical evaluation of composite fibre optic ground wires

Mechanical evaluation of composite fibre optic ground wires

STRESS-DEFORMATION CHARACTERISTICS OF CLAY IMPROVED BY SAND COLUMN UNDER TRIAXIAL STRESS CONDITIONS

To study stress deformation characteristics of composite grounds, drained triaxial tests on cylindrical clay specimen with a sand column are performed. By comparing the test results with analytical values which are calculated using “SMP model” for sand and “tij-clay model” for clay, it is confirmed that the present analytical results by these models describe well the test results of the composite ground. On the other hand, those analyses using “Nonlinear elastic model” for sand and “Modified Cam-clay model” for clay are also performed. The results cannot explain well the volumetric change and the share of stresses. It is clarified that the evaluations of the dilatancy and the intermediate principal stress are important in analyzing the composite ground.

A TWO-DIMENSIONAL FINITE ELEMENT METHOD FOR COMPOSITE GROUND UNDER THREE-DIMENSIONAL DEFORMATION

A TWO-DIMENSIONAL FINITE ELEMENT METHOD FOR COMPOSITE GROUND UNDER THREE-DIMENSIONAL DEFORMATION

Aerial and ground spectral characteristics of rangeland plant communities in Nevada

Visible and near infrared spectral reflectance values were recorded from Nevada rangeland plant communities using both low flying aircraft and ground measurement approaches. The individual spectrum values, four-band signatures and infrared: red scatterplots were used to compare 5 × 5 m aerial pixels with data from various ground components. Results show that vegetation and soil do not account for the integrated aerial spectra. The composite ground signatures indicate that spectrally dark components exist in rangeland plant communities which decrease the brightness of a scene measured from the air. Shadow and litter are presumed to be the primary sources of spectral darkening. An estimate of the overall signature of the shadow/fitter component was calculated.

STRESS CONCENTRATION ON SAND COLUMN DURING ONE-DIMENSIONAL CONSOLIDATION OF COMPOSITE GROUND

The stress and strain states of the Composite Ground composed of soft clay and sand columns during one-dimensional comsolidation, are studied by experiments and numerical analyses. The experiments are carried out on a model ground which includes a sand column and clay around it. Horizontal or vertical stresses and strains in sand and clay can be obtained separately in the experiments. The analytical model for the Ground are proposed and analized numerically. The results from the experiments agree well with ones of the analyses. It is clarified that the behaviors of the Ground can not be explained unless taking horizontal interaction of a sand column and clay into consideration.

Basic Components and Fiber Optic Passive Components: Status and Trends in Japan

This paper reviews the status and trends of Japanese activities in fiber optic passive components. It covers the fiber manufacturing techniques (VAD method), several special fibers such as polarization-holding fibers, dispersion-shifted fibers, infrared fibers, metal coated fibers, and hydrogen-induced loss problems, as well as various kinds of fiber cables such as trunk communication cable, subscriber cable, submarine cable, and optical fiber composite overhead ground wire. The paper also discusses the problems of splicing, connecting, and coupling with respect to future trends and provides information on progress in Japan in the expanding field of communication technique.

Laboratory and Field Tests on Composite Fiber Optic Overhead Ground Wire

Laboratory and Field Tests on Composite Fiber Optic Overhead Ground Wire

Testing of Composite Overhead Ground Wire Containing Optical Fibers

To determine whether composite overhead ground wire containing optical fibers can withstand extreme field conditions, mechanical and electrical tests were conducted on two types of composite wire. The performance of the composite units surpassed that of an existing overhead ground wire, confirming the feasibility of using them as combined ground wires and communication links.

Testing of Composite Overhead Ground Wire Containing Optical Fibers

Testing of Composite Overhead Ground Wire Containing Optical Fibers

Primitive and composite ground states in the fractional quantum hall effect

Our theory of the Fractional Quantum Hall Effect is reviewed. Arguments are presented that the fractionally charged quasiparticles associated with the effect are fermions. Wavefunctions for the 27 and 25 states are proposed, and estimates for the cohesive energies and gaps of these states are given.