Compact Cylinder Research Articles

Central Limit Theorems for Volume and Surface Content of Stationary Poisson Cylinder Processes in Expanding Domains

A stationary Poisson cylinder process in the d-dimensional Euclidean space is composed of a stationary Poisson process of k-flats (0 ≤ k ≤ d−1) which are dilated by independent and identically distributed random compact cylinder bases taken from the corresponding (d−k)-dimensional orthogonal complement. If the second moment of the (d−k)-volume of the typical cylinder base exists, we prove asymptotic normality of the d-volume of the union set of Poisson cylinders that covers an expanding star-shaped domain ϱ W as ϱ grows unboundedly. Due to the long-range dependencies within the union set of cylinders, the variance of its d-volume in ϱ W increases asymptotically proportional to the (d+k) th power of ϱ. To obtain the exact asymptotic behaviour of this variance, we need a distinction between discrete and continuous directional distributions of the typical k-flat. A corresponding central limit theorem for the surface content is stated at the end.

Functional and bioinformatic characterisation of sequence variants of Fad3 gene from flax

Desaturases are enzymes that drive the multi-step fatty acid biosynthetic pathway. As evident from directed mutagenesis, single base changes in their polypeptide can potentially alter their structure and may result in altered substrate specificity, regioselectivity and even loss of function. The authors have previously isolated several sequence variants of Δ15 desaturase from flax while attempting to clone that gene. The aim of the present study was to analyse these gene variants for their functionality and to predict the tertiary structure of the protein in order to correlate the functional differences with the protein structure. The variants differed in the rate at which they could convert linoleic acid to α-linolenic acid. The highest conversion rate was 7.03%, while the lowest was 2.39%. The overall shape of the predicted 3D model of the protein is a compact cylinder containing α-helices and β-sheets. The Ramchandran plot of this model revealed that 98.5% of the residues are located in allowed region, which denotes a stable structure. Although the structures of the variants are apparently similar, subtle changes account for variation in their activity. Besides, these substitutions may alter their cross-talk with other proteins and thus differentially influence their specificity, localisation and stability, which in turn may explain the diversity in their function.

Development of Articulated Manipulators with Pneumatic Cylinders

We have developed new articulated manipulators with compact pneumatic cylinders and with the high levels of structural flexibilities and safety as a result of adoption of new ideas in the structure. In developing the new articulated manipulators, we have first defined the design concepts and then described the overview of the manipulators which we have actually designed and manufactured. We have carried out experiments with the manufactured articulated manipulators for their positional controllability and stiffness characteristics, the results of which are also reported in this paper. Furthermore, this paper refers to possible applications of the developed new articulated manipulators.

The influence of induction hardening on the impact wear resistance of compacted graphite iron (CGI)

The aim of this work was to study the impact wear resistance of untreated and induction hardened compacted graphite iron (CGI). Testing was carried out on a bespoke impact wear test rig to look at the effect of the material properties, before and after hardening, on the level of wear. Three different types of specimen were tested; untreated CGI, CGI induction hardened to a nominal depth of 2 mm and CGI induction hardened to a nominal depth of 3 mm. Worn specimens were measured, optically and directly, and then analysed to characterise the likely wear mechanisms and wear debris. The induction hardening improved the impact wear resistance of the compacted graphite iron and when compared to the laser hardened cast iron it performed much better. Considering the proportion of wear in the valve and valve seat contact that is due to impact wear, it is likely that locally induction hardening a compacted graphite iron cylinder head could be a method of controlling the level of valve recession.

Fracture resistance and reinforcement of immature roots with gutta percha, mineral trioxide aggregate and calcium phosphate bone cement: a standardized in vitro model

Endodontic treatment of immature teeth is often complicated because of flaring root canals and open apices for which apexification is needed. Long-term prognosis for these teeth is surprisingly low because of cervical root fractures occurring after an impact of weak forces. In this study, an experimental model was developed to determine the fracture resistance of immature teeth and to test the hypothesis that endodontic materials succeed in reinforcing them. Compact and hollow bone cylinders from bovine femurs were used as standardized samples. In order to evaluate the experimental model, fracture resistance in both groups was evaluated by determining the ultimate force to fracture (UFF) under diametral tensile stress. Analysis of variance (ANOVA) revealed a statistically significant difference between the mean values of UFF for both groups, independently of the sampling location or subject. In a following setting, the hypothesis that obturation with gutta percha (GP), mineral trioxide aggregate (MTA), or calcium phosphate bone cement (CPBC) reinforces the hollow bone samples was investigated. Obturation resulted in a significant reinforcement for all materials, but the degree of reinforcement depended on the material. The experimental model appeared to be suitable for in vitro investigation of reinforcement and fracture resistance in a standardized way.

Observation of H2O Ice VI Single Crystals under High Pressure by Using Bridgman Anvils with a Compact Hydraulic Oil Cylinder

We describe a simple setup to observe H2O ice VI single crystals under high pressure by using transparent Bridgman anvils with a compact hydraulic oil cylinder. It is confirmed that growth and melting of the ice VI single crystal was clearly observed as reported in diamond anvil cell experiments. Furthermore, this setup allows students starting to learn high pressure experiments to understand the opposed anvil technique because the anvils are not only easy to manipulate but also visible even when pressure is generated.

Conformation-dependent Room-temperature Emission Spectra of Single MEH-PPV Chains in Different Polymer Matrices

Abstract Emission spectra of single molecules of the conjugated polymer MEH-PPV in host matrices of ZEONEX® and polystyrene are reported. Depending on the matrix, the polymer chains attain different conformations, from compact defect cylinders to extended defect coils. The conformations are correlated with photophysical properties, such as emission intensity fluctuations, and with shapes and peaks of emission spectra. The observed bimodal distribution of the spectral peaks is related to distribution in conjugated segment lengths.

Berry–Esseen bounds and Cramér-type large deviations for the volume distribution of Poisson cylinder processes

A stationary Poisson cylinder process (d;k) cyl is composed of a stationary Poisson process ofk-flats in R d that are dilated by i.i.d. random compact cylinder bases taken from the corresponding orthogonal complement. We study the accuracy of normal approximation of thed-volumeV (d;k) % of the union set of (d;k) cyl that covers%W as the scaling factor % becomes large. Here W is some fixed compact star-shaped set containing the origin as an inner point. We give lower and upper bounds of the variance of V (d;k) % that exhibit long-range dependence within the union set of cylinders. Our main results are sharp estimates of the higher-order cumulants of V (d;k) % under the assumption that the (d k)-volume of the typical cylinder base possesses a finite exponential moment. These estimates enable us to apply the celebrated Lemma on large deviations of Statuleviˇ cius. MSC: primary 60D05, 60F05; secondary 60F10, 60G55

SMC innovation gives the power and performance of a compact cylinder but the profile of a plate cylinder

SMC innovation gives the power and performance of a compact cylinder but the profile of a plate cylinder

Surface modes and photonic modes in Casimir calculations for a compact cylinder

A rigorous formulation of the problem of calculating the electromagnetic vacuum energy of an infinite dielectric cylinder is discussed. It is shown that the physically relevant spectrum of electromagnetic excitations includes the surface modes and photonic modes. The mathematical procedure of summing over this spectrum is proposed, and the transition to imaginary frequencies is accomplished. As a result, the imaginary-frequency representation for the vacuum energy is justified which has been used in previous Casimir studies for this configuration.

Difference in the root structure of hyperaccumulator Thlaspi caerulescens and non-hyperaccumulator Thlaspi arvense

The primary root structure of Zn/Cd hyperaccumulator Thlaspi caerulescens was compared with the root anatomy of closely related non-accumulator Thlaspi arvense. The most striking structure formed close to the root tip in T. caerulescens, but not in T. arvense, is the peri-endodermal layer of cells with irregularly thickened inner tangential walls. This layer observed in some species of Brassicaceae by early anatomists and described as 'reseau sus-endodermique' is composed of secondary cell walls impregnated by lignin, and it forms a compact cylinder encircling the endodermis. The differences in the proportions of individual tissues ? rhizodermis, cortex, stele and endodermis ? of the two species are statistically insignificant. However, there are differences in the cell arrangement. The precise function of the lignified cell wall thickening of the peri-endodermal layer of T. caerulescens is unclear at present. Some possible roles are discussed and its potential relation with metal hyperaccumulation and/or tolerance should be investigated.

Influence of a surfactant on single ion track etching: Preparing and manipulating cylindrical micro wires

The influence of the alkali resistant surfactant Dowfax 2A1 on single ion track etching in 30μm polycarbonate foils is studied at low etch rate (5M NaOH at 41.5±2°C) using electro conductivity measurements. At surfactant concentrations above 10−4vol.% break-through times are predictable (Δt/t<0.25). At high surfactant concentrations (⩾0.1vol.%) the formation of cylindrical channels is favoured. The shape of these channels (length⩾26μm, diameter⩾1.8μm) is verified by electro-replication and SEM observation of the resulting wires. Agreement of radii is better than 0.1μm. Depending on the current limit set during electro replication compact or hollow cylinders can be obtained. A technique for localizing and manipulating individual micro wires by their head buds is described.

Effects of stannous ions on the electrochemical performance of the alkaline zinc electrode

The effect of stannous ions as an electrolyte additive on the electrodeposition characteristics of Zn was investigated by chronoamperometry, the potential-step method and cyclic voltammetry. The chronoamperometry measurements showed that the addition of stannous ions inhibited the dendritic growth of Zn deposits. SEM observation also revealed that the Zn deposit was in the form of compact cylinders with rounded tops that consist of many small crystallites, rather than the classical dendrites with side branches. The inhibition effect of Sn2+ on the very initial electrocrystallization of Zn was not a substrate effect. The 0.17 V difference in reduction potential between Zn and Sn resulted in the codeposition of Sn and Zn. An interruption effect was proposed to illuminate the inhibition effect of Sn2+ on the formation of Zn dendrites. Furthermore, Sn2+ additive was found to suppress the corrosion reaction of Zn by 87% in the Sn2+-containing zincate electrolyte, comparing to that in the blank zincate electrolyte.

Modeling single-scattering properties of small cirrus particles by use of a size-shape distribution of ice spheroids and cylinders

In this study, we model single-scattering properties of small cirrus crystals using mixtures of polydisperse, randomly oriented spheroids and cylinders with varying aspect ratios and with a refractive index representative of water ice at a wavelength of 1.88 μm. The Stokes scattering matrix elements averaged over wide shape distributions of spheroids and cylinders are compared with those computed for polydisperse surface-equivalent spheres. The shape-averaged phase function for a mixture of oblate and prolate spheroids is smooth, featureless, and nearly flat at side-scattering angles and closely resembles those typically measured for cirrus. Compared with the ensemble-averaged phase function for spheroids, that for a shape distribution of cylinders shows a relatively deeper minimum at side-scattering angles. This may indicate that light scattering from realistic cirrus crystals can be better represented by a shape mixture of ice spheroids. Interestingly, the single-scattering properties of shape-averaged oblate and prolate cylinders are very similar to those of compact cylinders with a diameter-to-length ratio of unity. The differences in the optical cross sections, single-scattering albedo, and asymmetry parameter between the spherical and the nonspherical particles studied appear to be relatively small. This may suggest that for a given optical thickness, the influence of particle shape on the radiative forcing caused by a cloud composed of small ice crystals can be negligible.

Fracture resistance characterization of chemically modified crumb rubber asphalt pavement

The fracture resistance of chemically modified crumb rubber asphalt (CMCRA) pavement was evaluated based on the J-integral concept. The chemical modification process used was developed by the Federal Highway Administration and patented in 1998. The results were compared to that of crumb rubber asphalt (CRA) and control asphalt pavement. Four semi-circular core specimens (76 mm radius and 57 mm thickness) were cut from each gyratory compacted cylinder (GCC) for the fracture resistance tests. Notches with different depth to radius ratios were introduced at the middle of the flat surface of each specimen. Three point bend loading was used to allow the separation of the two surfaces due to tensile stresses at the crack tip. It was found that the CMCRA pavement, had the highest residual strength, at all notch depths tested. The fracture resistance of the CMCRA pavement, based on Jc was found to be about twice that of the CRA and control pavements. The CRA pavement was found to have a slightly higher fracture resistance than that of the control pavement. Scanning Electron Microscopic examination of the fracture surface of each mixture revealed the microstructural origin of the improved fracture resistance of the CMCRA pavement in comparison with the control pavement.

Wear of coal logs in pipe

The wear characteristics of small (49mm diameter) coal logs (i.e. compacted coal cylinders) having an approximate length of 76mm were tested in a steel pipe in the laboratory. For each individual test, three identical coal logs were compacted from the same batch of materials under the same compaction conditions. Six factors that affect coal log wear were varied in the tests, one at a time, to assess their individual effects. These factors include: coal type, binder concentration, coal log diameter, compaction temperature, water pressure encountered by coal logs, and pipe interior roughness. The results showed that logs made of subbituminous coal were more resistant to abrasion than logs made of bituminous coal. The addition of 0.5wt.% binder to coal mixture made logs six times more wear resistant than binderless logs. Coal logs prepared with larger diameter ratio and tested at lift-off velocity performed better than smaller diameter-ratio logs tested at the same velocity. Lift-off velocity is the minimum mean velocity of the fluid (water) at which the coal logs are completely suspended (levitated) by the flow in the pipe. An optimal compaction temperature of the order 80°C resulted in more wear-resistant logs than the other compaction temperatures tested. Testing coal logs in a pressurized pipe resulted in more durable and less abrasive coal logs. Finally, coal logs tested in a rough pipe encountered more wear than coal logs tested in a smooth pipe. The results of this study suggest that coal can be compacted at coal mines into strong cylinders (logs) for transportation to power plants by using large-diameter underground steel pipelines.

Diffusion of soluble salts under a temperature gradient after the hydration of compacted bentonite

The transport of the soluble salts contained in a compacted bentonite has been studied in a hydration and heating experiment. The objective is to follow the processes of transport produced during and after the hydration of compacted bentonite in order to detect the generation of localized saline environments under the presence of a temperature gradient. Permanent saline environments may affect the surfacial and swelling properties of a bentonite when used as a clay liner for the isolation of high-level nuclear waste (HLNW). Several hermetic cells have been designed to constrain an unsaturated compacted bentonite cylinder (dry density of 1.65 g/cm 3). The bentonite is moisturized by injecting an aqueous solution in an opposite direction to a heat source. The tests are conducted during pre-saturation to post-saturation stages. The hydration is carried out with two different solutions, synthetic granitic water of low salinity and saline water. Two gradients with different average temperatures are generated: 100–60°C (16°C/cm) and 60–35°C (10°C/cm). Convection and diffusion processes govern the transport of salts in the compacted bentonite. The temperature is the variable that mostly influences the processes of transport, while the concentration of the injected solution had smaller importance. The convective transport of salts, driven by the hydration, occurs in the presence of the thermal gradient. By means of this mechanism, the dissolved ions concentrate on the heated area of the cell. The process permits the measurement of apparent diffusion coefficients ( D a) for ions and salts during the homogenization of concentration profiles in the post-saturation stages. D a for Cl −, SO 4 2−, Br −, Ca 2+, Mg 2+, Na +, K +, Sr 2+ and Zn 2+ have been calculated. The values vary in the range of 1.5×10 −10–4×10 −12 m 2/s; the ions Cl −, Na + and Ca 2+ being of higher mobility. Codiffusion of Ca 2+ and Na + with Cl − is the main mechanism found for salt transport in the compacted bentonite.

Atypical Branching of Foxtail (Setaria spp.) Panicles in West-Central Kansas

Abstract Taxonomists describe panicles of green and yellow foxtail (Setaria viridis (L.) and S. glauca (L.) Beauv., respectively) as dense, contracted, narrow and cylindrical. However, a 6-y survey near Hays, Kansas documented inflorescences of green and yellow foxtail that were divided into two to four or more elongated segments. Those panicles were forked or digitate rather than a single compact cylinder. Anomalous panicles were always found on plants having several normal heads. Branched morphology was infrequent (<1 head in 10,000), but was observed in 1993 and 1995–1998. Before 1998 Kansas collections of foxtail specimens with abnormal panicles were limited to a 1600 × 3200 m area in central Ellis County. Observations during 1998 increased the known geographic distribution in Kansas to a 3200 × 3600 m area. Seed collected from branched panicles of both species and grown in greenhouse conditions did not produce plants with any aberrant inflorescences. Occurrence of deviant green or yellow foxtail pani...

Casimir energy of a compact cylinder under the conditionɛμ=c−2

The Casimir energy of an infinite compact cylinder placed in a uniform unbounded medium is investigated under the continuity condition for the light velocity when crossing the interface. As a characteristic parameter in the problem the ratio ${\ensuremath{\xi}}^{2}=({\ensuremath{\varepsilon}}_{1}\ensuremath{-}{\ensuremath{\varepsilon}}_{2}{)}^{2}/({\ensuremath{\varepsilon}}_{1}+{\ensuremath{\varepsilon}}_{2}{)}^{2}=({\ensuremath{\mu}}_{1}\ensuremath{-}{\ensuremath{\mu}}_{2}{)}^{2}/({\ensuremath{\mu}}_{1}+{\ensuremath{\mu}}_{2}{)}^{2}&lt;~1$ is used, where ${\ensuremath{\varepsilon}}_{1}$ and ${\ensuremath{\mu}}_{1}$ are, respectively, the permittivity and permeability of the material making up the cylinder and ${\ensuremath{\varepsilon}}_{2}$ and ${\ensuremath{\mu}}_{2}$ are those for the surrounding medium. It is shown that the expansion of the Casimir energy in powers of this parameter begins with the term proportional to ${\ensuremath{\xi}}^{4}.$ The explicit formulas permitting us to find numerically the Casimir energy for any fixed value of ${\ensuremath{\xi}}^{2}$ are obtained. Unlike a compact ball with the same properties of the materials, the Casimir forces in the problem under consideration are attractive. The implication of the calculated Casimir energy in the flux tube model of confinement is briefly discussed.

Influence of ground granulated blastfurnace slag on the sulphate resistance of lime-stabilized kaolinite

This paper describes the influence of ground granulated blastfurnace slag (GGBS) on the durability of lime-stabilized kaolinite in 4·2% Na2SO4 solution. Sulphate durability was assessed in the laboratory by means of linear expansions measurements, microstructure and mineral phase analysis of compacted cylinders of the lime-stabilized kaolinite with different percentages of lime replacement by GGBS. The cylinders were immersed in 4·2% Na2SO4 solution and also in deionized water for various time periods. The exposure test data showed that the effect of GGBS on reducing expansion in 4·2% Na2SO4 solution is dramatic. The results also showed that high percentages of replacement of lime with slag (in particular 83%), with just enough lime to activate the slag, were the most effective in preventing sulphate solution attack.