Thin Web Research Articles

An endoscopically proven ventriculitis-type, cyst-like intraventricular primary lymphoma of the central nervous system

Primary ventriculitis form of primary CNS lymphoma (PCNSL) is very rare and difficult to diagnose from radiological findings. A 55-year-woman presented with a cystic mass in the lateral ventricle without evidence of demonstrable malignant cells in the cerebrospinal fluid (CSF). The endoscopic biopsy showed a ventriculitis-like thin web on the surface of the ventricular wall around the foramen of Monro, resulting in obstruction. Pathological diagnosis was non-Hodgkin's lymphoma, B cell type. This case suggests that PCNSL should be considered as a differential diagnosis for a cystic ventricular lesion even with no malignant cells in the CSF.

Shear deformation in reinforced concrete beams with thin web

In this paper the main results of an experimental campaign, carried out to analyse the shear deformation and interaction between moment and shear on the global and local deformations of reinforced concrete (RC) ‘I’ section simply supported beams with thin web, are discussed. A new theoretical model, which considers the lattice-like behaviour and applies the constitutive laws of the modified compressive field theory, is also proposed. The ‘concrete contribution’ of shear strength resistance is theoretically calculated. Experimental and theoretical results are then compared, showing the rotation of the principal compressive strain axis in the web. The influence of shear deformation on the deflection of the tested beams with thin web reaches 25% of the total deflection.

Effect of Duct Type on Shear Strength of Thin Webs

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At your service [service-oriented architecture

For pt.2 see ibid., 44-7 (2005). SOA is fast way for organisations to unlock code buried in legacy systems. Although SOA is not tied to Web services, HTTP-based protocols such as the simple object access protocol (SOAP) have made SOA something that users can adopt with relative ease. In its purest form, SOA just means a way of building applications and systems out of a loose coupling of interacting software agents. For many, that coupling is through Web services and the front-ends to the first couple of generations of SOA are often simple, thin Web clients. In this article the author looks at how SOA might impact enterprise strategy.

Elastic distortional buckling of continuously restrained I-section beam–columns

Doubly symmetric steel I-section members with thin webs and stocky flanges that have their tension flange restrained fully against translational and lateral rotational buckling deformations and elastically against twist rotation during buckling by the flexibility of a continuous restraint have been shown in previous studies to buckle in a so-called restrained distortional buckling (RDB) mode, involving distortion of the web of the I-section in the plane of its cross-section. These bifurcative buckling modes must necessarily occur in the negative moment region of composite T-beams and in half-through girder bridges. The present paper describes the elastic RDB analysis of a simply supported doubly symmetric I-section beam–column subjected to combined uniform axial force and moment gradient. The study adopts an energy method of analysis. The numerical solutions are used to develop a simple method of predicting the elastic RDB loads of beam–columns for use in design.

Robustness of hollow clay masonry units and seismic behaviour of masonry walls

As the recent experimental investigations indicated, the robustness of masonry units is one among the most decisive parameters which define the behaviour of masonry walls when subjected to seismic loads. If local brittle failure of units occurs, the mechanism of behaviour and known relationships between the strength and ductility properties of masonry walls change. In such a case, the design values of load bearing and energy dissipation capacity of masonry walls are overestimated, although the equations and requirements specified in the codes have been taken into consideration. If brittle units are used for the construction of structural walls, the actual structure will be exposed to an increased level of seismic risk although it has been designed for earthquake loads according to codes. This is especially the case of reinforced masonry, where brittle local failure prevents the transfer of predicted forces from reinforcing steel to masonry units. In order to provide limitations for the use of hollow units with large hole volume ratio and thin shells and webs in seismic areas, a measure to define the qualitative term “sufficient robustness”, specified in Eurocode 8, should be found.

Vacuum Web Coating - State of the Art and Potential for Electronics

Going flexible seems to be a major trend for a variety of electronic applications such as displays, printed circuit boards, solar cells, and solid-state lighting. Driving forces, which may often include the function of "flexibility," are the potential to build units with less thickness and with less weight or the ability for very-large-area applications. Last but not least, there is the need for a remarkable reduction of production costs, which can be fulfilled by changing the production process from sheet processing to roll to roll. The first vacuum web coater was built 70 years ago, and vacuum web coating is currently used for a wide variety of applications. In the packaging industry, aluminum coating is primarily used for barrier improvement of plastic substrates. Such coatings are deposited with an evaporation process in machines of up to 4-m coating widths on rolls up to 60 000-m length and at coating speeds of more than 16 m/s. For capacitor production, thin webs with thicknesses down to the submicrometer range are vacuum-coated with aluminum, silver, or zinc layers, and uncoated stripes or patterns are also needed. Vacuum-coated web-shaped substrates can also be used for antireflective, antistatic function in the front of monitors, as window films for cars and architectural applications or as front electrodes for touch panels as a few examples. Different coating tools such as evaporation, sputtering, plasma-enhanced chemical-vapor deposition (PECVD), as well as pretreatment tools and inline layer measurement systems are available. Many of the currently available tools and processes existing in the web coating industry may become useful for upcoming electronic applications, but special demands for these new applications, such as exact area tracking, zero defects, roll-to-roll masking, and reduced substrate temperature during coating, require further development of machine design and process technology. This paper will summarize the state of the art of vacuum w

Telelearning in ophthalmology

The virtual ophthalmic clinic has been developed to provide an interactive learning platform within the correspondence courses of the Virtual University of Bavaria. It presents clinical case examples from ophthalmology. Basic concepts are a case-based learning dialogue (didactics), peer reviewing (quality), role-based access (organization), and thin web clients (availability). The following requirements had to be fulfilled: best possible accessibility for students, authors, and reviewers; learning control function; comfortable management. The application architecture is based on a relational data base, a ColdFusion (Allaire, Newton, MA) web application server, and a standard web server. So far, the application was used in four terms of the virtual university.—Hans E. Grossniklaus

Headed Studs in Concrete: State of the Art

Headed studs are smooth or deformed bars, usually short compared to the lengths of concrete members, with forged or welded heads for anchorage at one or both ends; they are used instead of conventional reinforcing bars anchored by hooks and bends. This article discusses several practical applications where the use of headed studs is appropriate. The authors note that the main advantages are simpler installation, less congestion of reinforcement, improved confinement, and more effective anchorage. The authors discuss applications for headed studs in slabs and footings, beams with thin webs, crossties in columns and walls, precast beams, deep beams and pile caps, and in beam-column joints. They conclude that use of a headed bar, as opposed to a bar with a hook, is advantageous in applications where there is demand for the yield strength at a section of the bar close to its end.

Cooperative Charging Effects of Fibers from Electrospinning of Electrically Dissimilar Polymers

Electrical charging and residual charge decay of electro-spun nonwoven webs comprised of two electrically dissimilar polymers were studied in an effort to investigate their filtration properties. Polystyrene (PS) and polyacrylonitrile (PAN) were electrospun separately, in a layer-by-layer configuration and simultaneously in a side-by-side bi-component apparatus into thin webs on a polypropylene spunbond substrate. During electrospinning of the PS and PAN polymer solutions, the fibers became positively charged when positive voltage was applied to the solution-filled spinning nozzle and became negatively charged when negative voltage was applied. This study was undertaken to examine the effect of cooperative charging from electrospinning of the two polymers, the effect of the three types of web constructions on charge retention, and filtration properties of the fibers. It was found that single, multilayered, and bi-component webs retained surface charges in the thousands of volts that diminished very little over a 20-hour period, but eventually bled off while resting for three months. Filtration properties were found to be exceptionally high for some, but not all, electrospun samples; filtration was found to have a weak dependence on both surface charge and web geometrical factors, particularly the fiber diameter, that influence pressure drop of the aerosol test.

Multi Frequency Solution of Chatter Stability for Low Immersion Milling

Finish milling is usually required in the peripheral milling of thin aircraft webs with long end mills, where the structures are flexible and radial depths of cut are small. The spindle speed and depth of cut must be selected optimally to avoid both forced and chatter vibrations, which in turn enables production of the parts within specified tolerances. Recent articles show that stability pockets differ at certain speeds when the radial immersion in milling is low and the machining process is highly intermittent. This paper presents a stability theory which predicts chatter stability lobes that are not covered by classical chatter theories in which the coupling between the spindle speed and process stability are neglected. The dynamics of low radial immersion milling are formulated as an eigenvalue problem, where harmonics of the tooth spacing angle and spread of the transfer function with the harmonics of the tooth passing frequencies are considered. It is shown that the stability lobes are accurately predicted with the presented method. This paper details the physics involved when the tooth passing frequencies alter the effective transfer function of the structure in the stability solution. The products of the harmonics of the directional coefficients and transfer functions of the structure are evaluated at the natural mode under the influence of tooth passing frequency harmonics in order to obtain the exact locations of chatter stability lobes.

Buckling of stiffened plates with bulb flat flanges

The subject of this research is the buckling behavior of a rectangular plate, with a bulb flat stiffener attached to one side of the plate. The stiffener cross section has a thin web and a bulb flat flange that extends to one side of the web. The stiffened plate structure is subjected to axial compression that increases to the buckling load. Results of the investigation include planar property formulas for the asymmetric flange geometry, an analytic expression for the Saint-Venant torsional constant of the flange cross section, and an analytic expression for the buckling stress corresponding to a tripping mode of the structure. The torsional constant for the bulb flat stiffener is 15–23% higher than understood previously. The analytic expression for the buckling stress of a bulb flat stiffened plate differs by less than 4% from finite element and experimental results.

High-power Er:Yb fiber laser with very high numerical aperture pump-cladding waveguide

One watt of laser power at 1535 nm has been generated from an Er:Yb codoped double-clad fiber structure, in which the inner cladding was suspended in air by a large number of thin silica webs. The acceptance numerical aperture (NA) of the inner cladding has been measured over a range of wavelengths, for lengths from 1 up to 100 m. For fiber lengths of ∼40 m, the NA at the pump diode wavelength was 0.88.

Analytical evaluation of built-up shear links under large deformations

This paper presents the results of nonlinear finite element analyses conducted on built-up shear links designed according to AISC Seismic Provisions for Structural Steel Building. The webs in these links are expected to yield in shear during large seismic events. Traditionally, these links are designed and constructed utilizing rolled shape sections. This paper discusses the potential of using built-up sections with relatively thin webs and thick flanges as shear links. The strain and stress distributions along critical sections of the web are presented in this paper. The results of the analytical investigation showed good agreement with the experimental value of the ultimate shear capacity. A series of parametric studies on web compactness ratios and stiffener spacing were carried on to study their effect on the overall plastic rotation of the built-up link. Based on these analyses, an equation that relate the plastic rotation to the web compactness and stiffener spacing was recommended.

Himantormia lugubris (Hue) M. Lamb – vegetative and reproductive habit: adaptations of an Antarctic endemic

Summary Himantormia lugubris has developed special growth strategies as well as special structures on morphology and anatomy. H. lugubris , an antarctic endemic, is distributed on the islands of the northern maritime Antarctic and along the Antarctic Peninsula (to the Argentine Islands). The rock surface is colonized by a thin web of hyphae from which a horizontal thallus emerges resembling a dark crustose lichen. Numerous bacteria, cyanobacteria and algae are associated with the horizontal thallus and the prothallus, but without lichenisation. Vertical growth starts from the horizontal thallus developing unlichenised or lichenised stipes. Older vertical strap-shaped thalli form a mass of chondroid mechanical tissue composed of conglutinated hyphae without algae. The algae in the vertical thallus are either carried upwards during growth or incorporated from the environment. Ascocarp development is typical for the Parmeliaceae. The commonly small number of photobiont cells may explain the low primary production in relation to thallus weight. For nutrition the horizontal thallus seems to depend on the associated numerous algae, bacteria and cyanobacteria. The number of algal cells in the primordia of the vertical branches seem to be sufficient for energy gain and growth. The major part of the thallus of H. lugubris does not participate in energy gain only acts as supporting tissue and facilitates water transport. The lichen has a pronounced K-strategy. The definition of life-strategies in Antarctic lichens is discussed.

Unraveling the Organization of the Internal Nuclear Matrix: RNA-Dependent Anchoring of NuMA to a Lamin Scaffold

Using quantitative immunoelectron microscopy we show here that when the nuclear matrix is isolated from rat hepatocytes in the presence of an inhibitor of RNase activity both lamins and the nuclear mitotic apparatus protein (NuMA) preferentially localize within the electron-dense domains of the internal nuclear matrix (INM). After RNA digestion NuMA undergoes a sharp depletion, while labeling by an antibody against lamins A and C within the electron-transparent regions increases, suggesting that a subset of lamin epitopes is masked by the interaction with RNA. We were able to explain this result by visualizing for the first time a thin web of lamin protofibrils which connects the electron-dense regions. Confirmation of these changes has been obtained by immunoblot analysis and confocal microscopy. As RNA digestion results both in the release of NuMA and in the collapse of the INM, we propose that a fraction of nuclear RNA brings about the association of NuMA islands with a lamin scaffold and that this interaction is required to maintain the latter in a state of high molecular dispersion.

A safe percutaneous method to recanalize sharp venous occlusions that resist the passage of guidewires.

It is occasionally necessary to cross a sharp venous occlusion (a thin web of tissue without a lumen) and sometimes it is not possible to cross the stricture with a wire, so puncturing it with a sheathed needle is then required to enable stenting. Other methods have been reviewed; however, we think this balloon technique makes it a safer procedure.

A Model for Determining the Asperity Engagement Height in Relation to Web Traction Over Non-Vented Rollers

The traction developed between a thin flexible web, wrapped around a non-vented, rotating cylindrical roller is studied experimentally and theoretically. A series of eight webs representing a wide range of surface roughness characteristics are traction-tested against the same roller over a wide speed range. A mathematical model that couples air film pressure, web deflection, and asperity deformations is used to model the web/roller interface. An optimization technique is used to estimate the asperity compliance function parameters based on the experimental results and the mathematical model. A new model for determining the asperity engagement height, for surfaces with non-Gaussian peak height distribution, is proposed when the roughness of both surfaces is taken into account. Results are presented that indicate the viability and utility of the new methods.

Spacing and Friction Characteristics between Roller and Transporting Web with Different Permeabilities. 2nd Report. Theoretical Model for Friction Coefficient and Its Experimental Verifications.

In this second paper, the friction characteristics between roller and thin flexible web with different permeabilities is studied theoretically and experimentally. At first step, the standard test is carried out for three kinds of webs, PET (polyethylene terephthalate), coated paper and newsprint, for better understanding the friction characteristics between roller and web. Then, two types of power low model for the averaged contact pressure due to asperities of web and roller surfaces is presented, in which the unknown parameters involved in the models are determined by the inverse analysis to the standard test results of friction coefficient. Combining the contact pressure models developed here with the closed-form formula for air film thickness derived in the first paper, the prediction method of friction coefficient between web and roller is formulated. The air film thickness and friction coefficient are measured by changing the web width for three kinds of webs, and good agreements are obtained between the measured results and the predicted results. Moreover, based on these results, the effects of many design parameters on the friction characteristics are clarified.

Flutter Limits of Flexible Thin Webs with a Basic Configuration in High-Speed Flow. 2nd Report. Predicted Effects of Several Influential Factors on the Flutter Limits.

Flutter characteristics of flexible webs affected by several influential factors are investigated by the analytical method described in a previous study. The factors include the following : (1) mass ratio, (2) fluid surface friction, (3) presence of nearby wall (s), and (4) web movement. In the region of medium tension/bending-stiffness where progressing waves of lower-order modes dominate, mass ratio and fluid friction have little effects on the flutter speeds and conditions. The web movements, however, have a significant effect in lowering the flutter speeds. Presence of nearby walls causes considerable changes in the flutter speeds and conditions particularly for the ratio of gap to web length below 0.3.