Half Ellipse Research Articles

Design of a large effective mode area photonic crystal fiber with modified rings

A photonic crystal fiber (PCF) is proposed that, through novel design, achieves an enhanced effective mode area. The PCF is composed of two concentric elliptical cores. The central core is un-doped silicon whilst the second, outer core region, is doped. The outer doped region is also bordered by lightly doped half ellipse segments. The effective mode area of the structure was calculated and compared with the mode area of conventional PCF's. Our results show that the mode area and chromatic dispersion are very sensitive to the geometry, dimensions and placement of the lightly doped segments. The chromatic dispersion, bend losses and the nonlinear coefficient are also numerically simulated and presented in this paper.

Mechanical behaviour of HTR materials: Developments in support of defect assessment, structural integrity and lifetime evaluation

Mod 9Cr–1Mo steel (T91) is a candidate material for pressure vessels and for some internal structures of GCR (Gas Cooled Reactors). In order to validate this choice, it is necessary, firstly to verify that it is able to withstand the planned environmental and operating conditions, and secondly to check if it is covered by the existing design codes, concerning its procurement, fabrication, welding, examination methods and mechanical design rules. A large R&D program on mod 9Cr–1Mo steel has been undertaken at CEA in order to characterize the behaviour of this material and of its welded junctions. In this program, the role of the Laboratory for structural Integrity and Standards (LISN) is to develop high temperature defect assessment procedures under fatigue and creep loadings. Concerning the GCR, complementary studies are conducted in order to validate the existing methods (developed for the fast reactors) and to get new experimental data on Mod 9Cr–1Mo steel. Moreover, if the geometry and the loadings of a standard CT specimen allow performing a 2D analysis, the case of industrial loadings appears much more complicated, notably because of surface defects which propagate and present shapes that can be considered as half ellipse. Therefore, in the frame of the defect assessment methods validation, the LISN undertakes both standard tests on CT specimens to determine the propagation laws and bending tests on large plates under high temperature fatigue and creep loadings. These components present an initial semi-elliptical surface notch normal to the loading direction and its initiation and propagation are studied.

Modeling corroded section configuration of steel bar in concrete structure

Predicting concrete cover cracking due to steel bar corrosion in concrete is an important problem for durability of reinforced concrete structures. A basic question in the prediction is distribution of corroded part of steel bar section. The corrosion products have characteristic of volume expansions; that leads to expansive pressure in the concrete. At present, an assumption of uniform corroded pattern along the perimeter of the steel bar has been adopted for analyzing the effect of corrosion products expansion and building the model. In this paper, the steel bars in concrete were corroded under artificial climate environment for accelerated aging. The propagation of the corrosion products layer between steel bar and concrete and its microstructure are discussed; and then, the corrosion products distribution called corrosion products layer on the steel bar in concrete is revealed. The distribution before corrosion cracking; the corrosion products distribute on the half circumference of the steel bar facing the concrete cover only, and the distribution has the shape of a half ellipse. Because of expansive characteristic of corrosion products, the distribution pattern of the corroded part of the steel bar section is proportional to the distribution of the corrosion products layer. Therefore, the configuration model of corroded steel bar section is built.

Predicting Wetland Plant Community Responses to Proposed Water-level-regulation Plans for Lake Ontario: GIS-based Modeling

Integrated, GIS-based, wetland predictive models were constructed to assist in predicting the responses of wetland plant communities to proposed new water-level regulation plans for Lake Ontario. The modeling exercise consisted of four major components: 1) building individual site wetland geometric models; 2) constructing generalized wetland geometric models representing specific types of wetlands (rectangle model for drowned river mouth wetlands, half ring model for open embayment wetlands, half ellipse model for protected embayment wetlands, and ellipse model for barrier beach wetlands); 3) assigning wetland plant profiles to the generalized wetland geometric models that identify associations between past flooding / dewatering events and the regulated water-level changes of a proposed water-level-regulation plan; and 4) predicting relevant proportions of wetland plant communities and the time durations during which they would be affected under proposed regulation plans. Based on this conceptual foundation, the predictive models were constructed using bathymetric and topographic wetland models and technical procedures operating on the platform of ArcGIS. An example of the model processes and outputs for the drowned river mouth wetland model using a test regulation plan illustrates the four components and, when compared against other test regulation plans, provided results that met ecological expectations. The model results were also compared to independent data collected by photointerpretation. Although data collections were not directly comparable, the predicted extent of meadow marsh in years in which photographs were taken was significantly correlated with extent of mapped meadow marsh in all but barrier beach wetlands. The predictive model for wetland plant communities provided valuable input into International Joint Commission deliberations on new regulation plans and was also incorporated into faunal predictive models used for that purpose.

The refractive index distribution of Tl+–Na+ ion-exchanged glass waveguide optical splitter in branch district

The buried waveguide optical splitter is fabricated by Tl+–Na+ ion-exchange technology on BK7 glass substrates, and the refractive index distribution in branch district is analyzed by the interference method technology. The shape of the same refractive index distribution of the six successive different points in branch district is changed little by little from a semicircle to a half ellipse gradually, and finally separates into two semicircles. We also compare the experiment data by the interference method with the mathematical solution by two-dimensional diffusion equation. And the refractive index distribution is the ‘improved’ Gauss function.

Mechanical detector for tractors automatic guidance

Automatic guidance systems for tractors improved track accuracy and inter-row operating performance,reduced the intension of driver.The mechanical guidance for tractors detected path by contact crops,stubbles or furrows in the field with simple structure that easy to maintain and lower cost.A low cost equipment of mechanical detector for tractors to auto- matically guide in standing maize stubbles field is presented. The symmetrical frame of the detector and half ellipse shape of the feeler are designed by analyzing characters of detector sensing in stubbles rows.The main parameter such as space between center of ellipse and that of rotation axle is provided on the base of analyzing feeler forces and rotation movement in dynamics.The result of test showed that the automatic guidance equipment with half ellipse shape of the feeler and angle sensor is capable of detecting the guidance rows of standing maize stubbles.

Infrared characteristics of acidic droplet in different movement states on the surface of GaAs

Using the infrared thermal image real-time monitoring system developed independently in our laboratory, the infrared characteristics of H2SO4-H2O2-H2O droplet in different movement states on the surface of GaAs substrate is studied, including, for instance, the static state, the slow motion state and the quick motion state. The obtained experimental results and the merit of our system are discussed. The main conclusions drawn from the experiments includes: In the static state, the created heat produces convection inside the droplet, the peak value of infrared radiation distribution is located at the top of droplet and the heat diffuses to the ambient along GaAs substrate, which causes the radiation to drop steeply at the edge of droplet. In the slow motion state, the residual heat phenomenon revealing as “comet tail" is observed when the droplet moves across the substrate surface, and as the temperature decreases, the radiation peak “co-moves” with the droplet in the same direction, in addition, the displacement curve of the radiation peak lags behind the actual displacement of the droplet and the maximum temperature may appear in the “comet tail”. In the quick motion state, the phenomenon shows as “liquid film trace" because the droplet leaves the substrate without reacting with GaAs, and the value of infrared radiation varies smoothly, showing in the gray_scale pattern as a half ellipse extending from the edge to the center of liquid film. The distribution and characteristic variety of grey-scale in the center of the trace is also analyzed. The proposed infrared monitoring system of thermal behavior of moving droplets will prompt the research of the droplet itself as well as the interdisciplinary studies, in which, for example, the infrared technology being introduced into material sciences and chemistry sciences and so on.

Ni-Cr-Mo 鋼ブレーキディスクの摩擦熱影響により発生する微視熱き裂の観察

In order to origin of thermal cracks initiation to the brake disc in Ni-Cr-Mo alloy steel was investigate, crack initiation and propagation morphology was performed by brake test and observation of microstructure in this study. It was found that the propagation morphology of generated cracks were shell likes and half ellipse morphology for surface and through thickness. Driving force of crack initiation and propagation was caused by thermal fatigue. The origin of thermal fatigue cracks was peculiar structure which were shown by effect of thermal activation during wear. It was considered that the thermal crack was generated by load of tensile stress to the carbide in peculiar structure.

Effects of Air Void at the Steel-Concrete Interface on the Corrosion Initiation of Reinforcing Steel in Concrete under Chloride Exposure

A series of reinforced G109 type specimens was fabricated and pended with a 15 weight percent NaCl solution. Mix design variables included 1) two cement alkalinities (equivalent alkalinities of 0.32 and 1.08), 2) w/c 0.50 and 3) two rebar surface conditions (as-received and wire-brushed). Potential and macro-cell current between top and bottom bars were monitored to determine corrosion initiation time. Once corrosion was initiated, the specimen was ultimately autopsied to perform visual inspection, and the procedure included determination of the number and size of air voids along the top half of the upper steel surface. This size determination was based upon a diameter measurement assuming the air voids to be half spheres or ellipse. The followings were reached based upon the visual inspection of G109 specimens that were autopsied to date. First, voids at the steel-concrete interface facilitated passive film breakdown and onset of localized corrosion. Based upon this, the initiation mechanism probably involved a concentration cell with contiguous concrete coated and bare steel serving as cathodes and anodes, respectively. Second, the corrosion tended to initiate at relatively large voids. Third, specimens with wire-brushed steel had a lower number of voids at the interface for both cement alkalinities, suggesting that air voids preferentially formed on the rough as-received surface compared to the smooth wire brushed one.

Discussion of “Thrust Restraint Design of Concrete Pressure Pipe” by Mehdi S. Zarghamee, Daniel W. Eggers, Rasko P. Ojdrovic, and Daniel P. Valentine

The authors are to be complimented on their development of a design procedure for restraint of pressure-induced thrust at bends in pipelines, using concrete pressure pipe, which includes the effects of soil resistance to lateral movement of tied-pipe. The authors’ procedure is a needed extension of a beam-on-elasticfoundation design procedure for thrust restraint of fiberglassreinforced plastic pipe and fittings developed in the late 1970s Ameron 1980 , but it is found to be lacking in some respects. Throughout this discussion, is substituted for the authors’ for compatibility with AWWA 1996 . In the authors’ Eq. 3 the third term, 2klb cos 2 /2 referred to herein as T3, represents passive soil-pressure forces that act on the bend to resist thrust T. The fourth term of Eq. 3 2fulb sin /2 referred to herein as T4, represents friction forces that act on the bend to resist thrust. Both terms are incorrect because they are not based on movement of the bend into the soil in the direction of the thrust force and because all bends are treated as having only a single mitered joint. The correct third term is T3 =k lk where lk is the effective length of the projection of the outer surface of the entire bend on a plane perpendicular to T. That projection is a rectangle of length 2lb cos /2 and width Do, with half ellipses appended to its ends. The major axis of the ellipses is Do and the minor axis is Do sin /2 . The effective projected length, which is equal to the projected area divided by Do, is lk=2lb cos /2 + /4 Do sin /2 . The correct fourth term is T4 = f l where l is the sum of the centerline lengths of each of the mitered sections of the bend. Using the guidelines for the design of mitered bends in AWWA 1996 , l =2 lb −R tan /2 + ns−1 R tan /2 , where lb is equal to L1 from Table 1 of AWWA 1996 , R is the radius of the bend, ns is the number of mitered sections and = / ns−1 . For Do=1,829 mm 72 in. values of T3 /T3 range from 0.9 to 1.4 for values of from 7.5° to 90° and R from 1.0Do to 2.5Do. Values of T4 /T4 range from 15.3 to 2.0 over the same ranges of and R. The differences represented by the ratios, especially T4 /T4, are significant. The authors’ depend upon axial friction forces on tied pipe from vertical loads We, Wp, and Wf to resist thrust force, but they neglect friction forces produced by lateral soil pressure against the pipe. The total lateral force producing friction along the springlines of pipe is equal to 2Vo, and, because lateral friction pressure is greatest near the bend, it could be significant in reducing the amount of longitudinal reinforcement of the first few tied pipe as well as the number of tied pipe. It seems overly conservative to neglect the effect of friction from lateral soil pressure.

Healing of dehiscence‐type defects in implants placed together with different barrier membranes: a comparative clinical study

Premature exposure of membranes used in guided bone regeneration (GBR) results in decreased bone formation. The effect of an expanded polytetrafluoroethylene (e-PTFE) and two collagen membrane on bone healing of buccal dehiscence defects around implants in cases with and without premature membrane exposure was clinically evaluated. Three groups were established: Group OS (Ossix, n=73 implants, 41 patients), Group BG (Bio-Gide, n=53 implants, 28 patients) and Group GT (e-PTFE, Gore-Tex, n=34 implants, 17 patients). Defect height and width were measured at the time of implant placement and at second stage surgery. Surface area was calculated as half ellipses. When several implants were placed simultaneously, a mean of their defect width and height was calculated. Mean percentage reduction of defect area (92.2+/-13.78% Group OS, 94.6+/-6.69% Group BG, and 97.3+/-4.91% Group GT) and height (81.6+/-23.19%, 85.4+/-12.26%, and 93.4+/-9.39% respectively) did not show statistically significant differences between groups. Differences between groups were not statistically significant for all parameters when cases without spontaneous membrane exposure were compared. However, differences were significant when spontaneous membrane exposure occurred. Mean percentage reduction of defect area among cases where membrane exposure occurred was 91.5+/-10.86% Group OS, 71.5+/-8.61% Group BG, and 73.7+/-13.97% Group GT. Mean percentage reduction of defect height among cases with membrane exposure was 76.4+/-18.28%, 53.4+/-9.86%, and 49.4+/-11.05%, respectively. Premature exposure of membranes and subsequent and consequent exposure of implants results in impaired bone healing. Certain barrier membranes, as used in group OS, are apparently capable of supporting gingival healing even when prematurely exposed that could be advantageous in GBR procedures.

Irsogladine Maleate Inhibits Angiogenesis in Wild-Type and Plasminogen Activator-Deficient Mice

Background.The activation of the zymogen plasminogen to the serine protease plasmin by urokinase-type (uPA) and tissue-type (tPA) plasminogen activators (PA) is an important event in a variety of physiologic and pathophysiologic processes in mammals. Enhanced PA activity occurs during angiogenesis and has been correlatedin vitroandin vivowith increased tumor aggressiveness and is an indicator of poor prognosis in a variety of tumors in humans. Preliminary studies suggest that the antiulcer drug irsogladine maleate (IM) diminishes PA activityin vitroand may inhibit angiogenesisin vivo.To define the precise mechanism of angiogenesis inhibition by IMin vivo,we tested the ability of IM to blunt angiogenesis in a mouse cornea neovascularization model performed in wild-type and PA-knockout mice.Methods.Three days prior to pellet implantation, groups of C57Bl/6 wild-type, uPA-deficient (upA−/−), and tPA-deficient (tPA−/−) mice received IM (300 mg/kg), IM (500 mg/kg), or vehicle (0.5% carboxymethylcellulose) via oral gavage. After 3 days of treatment, hydron polymer-coated pellets of sucrose aluminum sulfate containing 100 ng of basic fibroblast growth factor (bFGF) were inserted into surgically created pockets in the cornea of each mouse. On postoperative day 6, the neovascularization of each cornea was evaluated by a blinded observer using slit lamp microscopy and photographed. Angiogenesis was quantified by calculating vascular area (mm2) ± SEM using a modified formula for a half ellipse that incorporates calibrated vessel measurements [Vessel length (mm) × Clock hours × π × 0.2].Results.IM treatment (300 and 500 mg/kg/day) resulted in a dose-dependent reduction of angiogenesis in wild-type mice by 21 and 45.3% (P< 0.02,P< 0.001), in tPA-deficient mice by 42.6 and 46% (P< 0.001,P< 0.001), and in uPA-deficient mice by 27.2 and 46% (P< 0.05,p< 0.001), respectively. No quantitative differences in neovascularization were observed in either treatment group between transgenic mouse strains. No toxicity was noted in any group.Conclusion.IM inhibits bFGF-induced angiogenesis in wild-type, tPA-knockout, and uPA-knockout mice. The observation that IM significantly diminishes angiogenesis in both PA-deficient mice and wild-type mice suggests that the mechanism of action of IM may be independent of plasminogen activation.

Identification of operational clues to dry weight prescription in hemodialysis using bioimpedance vector analysis

Identification of operational clues to dry weight prescription in hemodialysis using bioimpedance vector analysis

Development and Evaluation of Large-Scale Impeller Generating Strong Circulation Flow Suitable for Wide Viscosity Range in Reactor with Cooling Coil.

For radical addition polymerization, the viscosity of the fluid rapidly increases with increasing conversion. In such a polymerization, one of the most important characteristics is to mix the entire fluid in the reactor and rapidly remove the reaction heat. For this purpose, we made a large-scale impeller (called an experimental impeller hereafter) which is a combination of a paddle impeller for low viscosity and a half ellipse impeller for high viscosity with the purpose of using it for the wide viscosity range that occurs during polymerization. The effectiveness of the experimental impeller is compared with a multistage pitched blade turbine, anchor impeller, helical screw impeller and helical ribbon impeller based on circulation time, power characteristics, mixing time and mixing efficiency. Actual radical addition polymerization was performed using these impellers. Each impeller is evaluated by comparing the uneven temperature distribution generated in the reactor equipped with the coil and the physical properties of the produced polymer. Furthermore, the change in the heat transfer coefficient of the cooling coil, which is related to the fluid flow, was measured during polymerization using the experimental impeller, a helical screw impeller and a multistage pitched paddle turbine.As a result, it is clarified that this experimental impeller generates strong axial circulation in the polymerization field, so that even with a large change in the viscosity range, polymerization is steadily performed.

Estimation of the index profile parameters of a GRIN optical waveguide and fringe synthesis applying multiple beam interference

Multiple beam Fizeau fringes across a GRIN fibre immersed in a silvered liquid wedge have been obtained using matching and non-matching liquids. An image processing system has been used to analyse the fringe shape across the fibre cross section. A simple mathematical approach has been applied, utilizing the resulting experimental data to estimate the fibre index profile parameters. A detailed synthesis of the experimentally secured fringes across a GRIN fibre has been obtained by analysing the fringe shape into its components. In the case of a matching liquid it is found to be composed of half an ellipse and a saddle, another half ellipse is added for non-matching liquids. This is achieved utilizing the index profile parameters estimated.

The effects of three-dimensional imposed disturbances on bluff body near wake flows

Wind tunnel and water flume experiments have been carried out on a half ellipse model with a blunt trailing edge, the aim being to study the three-dimensional nature of vortex shedding. The trailing edge of the model can be either straight or mildly wavy. Introducing waviness reduces base drag, with the reduction higher at the peaks of the waves, corresponding to where the chord is a maximum, than at valleys. Two vortex shedding frequencies are observed and there are two main modes of shedding, one where it is symmetric about a peak and the other where it is antisymmetric. Vortex splitting is a common feature observed in the flow and this occurs in order to accommodate changes in shedding frequency along the span. Behind a straight trailing edge vortex splitting occurs at random positions whereas superimposed waviness tends to fix where the splitting take place.

Multiple-beam interferometric studies on optical fibres

The fringe shape across a graded index (GRIN) fibre immersed in a silvered liquid wedge, when analysed to its elements, is found to be the result of two half ellipses and a saddle. For a step index fibre, the elements contributing to its fringe shape are merely two half ellipses. Using a matching liquid cancels the outer half ellipse in both cases. The central dip contributes an extra half ellipse and a saddle over the dip but in the reverse direction away from the wedge apex. Such analyses furnishes the basis of a method to deduce the characteristics of GRIN fibres, namely alpha and Delta n, which is tested on liquids of different refractive indices.

線材・棒鋼圧延の負荷特性とその数式化

This paper describes a new method for calculating roll force and torque in Square_??_Oval, Round_??_Oval, Square_??_Diamond, Oval→Oval, and Diamond→Diamond passes. We conducted hot steel bar rolling experiments, and investigated some characteristics related with roll force and torque. The shape of projected contact area can be approximated as follows; in the Square→Oval pass, it is approximated by concave rectangular; in the Round_??_Oval, Oval→Oval and Oval→Square passes, by half ellipse; in the Square_??_Diamond and Diamond→Diamond passes, by cosine curves. The mean deformation resistance can be calculated by an equivalent rectangular transformation method. The non-dimensional roll force and torque arm coefficient are expressed as simple functions of a common roll gap ratio.

隅肉溶接に対する溶込みの算定(第II報)

In the 1 st report, fundamental formulas and diagrams for welding penetration have been obtained using idealised models of a moving point heat source, and practical application to shallow penetration of fillet weld was discussed.In this report, the fundamental penetration theory is applied practically to deep fillet weld as follows:(1) Assuming geometrically a half ellipse of fused zone in a fillet weld cross-section, the actual penetration (d, d0. and p; see Fgi. 4) of a fillet weld is represented by the following approximate formulas as a function of theoretical penetration (d) derived from the point-source theory:Nominal penetration ......d/h=1/2{√(2d/h)4+1-1}Root penetration ..........d0/h=1/√2{(2d/h)2-1}Efiffective penetration ......p/h=(2d/h)4-1/(2d/h)4+1where, h is a given fillet size, and d is obtainable from the given welding condition and material. (see report I)(2) Reduction rate of fillet size (he/h) due to effective penetration (p) is also given by the following approximate formula:he/h=2/(2d/h)4+1where, he is the reduced fillet size, and h is the required nominal fillet size.(3) Utilities of the formulas are experimentally confirmed by submerged arc welding of Tee-joints.(4) The theory of both-sides penetration of Tee joint welded simultaneously which was presented in the 1st report is also confirmed experimentally for the deep fillet welds by submerged arc welding.

STUDIES ON A GROUP HEARING EXAMINATION METHOD OF SCHOOL CHILDREN

I investigated the following matters: The quality and quantity of sound sauce and its place; the construction of class room (wooden or concrete made) and its size; the difference of sound pressure levels distribution when the pupils are on or not in the class room; the difference of articulatory degree at verious point in the room. Conclusions 1) When the sauce of sound pressure (pure tone, white noise and speech tone) is on the teacher's desk in a wooden made class room, the distributions figure of sound pressure level in the room forms the typical shape such as draw a concentric circle in u half ellipse with major axis on the center line of the room. It decreases proportionally with the distance from the sound sance, but on a sideline of the room, such declination is hardly found. The sound level decline degree at the center line is much smaller in the class room of concfete made than that of wooden made under the same condition. Pattern of distribution of the sound pressure level is very different in each case (concrete or wooden made class room) and the considerable diffe-rence in the sound pressure distribution can be recognized in diagram. 2) The decline dgree of sound pressure level is larger when pupils are in the class room. 3) The pattern of equal articulatory degree line of pure tone sound and speech tone sound in the room is similar to that of equal sound pressure level line. 4) Correlation between articulatory degree of speech tone (mono syrable word sound) and of some pure tone sound are computed with 136 pupils. And the correlation coefficiente is shown as follows; pure tone sound 4 KCPS is the highest coefficient 0.69, 2 KCPS is 0.30, 0.5 KCPS is 0.28 and 1 KCPS is 0.0.