Large Flange Research Articles

An ultra-high-vacuum mirror box with three remotely-operated water-cooled mirrors for the U13U wiggler/undulator spectroscopy branch line at the national synchrotron light source

We describe an ultra-high-vacuum mirror box with three independent remotely operated water-cooled mirrors which serve to focus a diverging input beam onto a common focal point. Each of the mirrors may be adjusted by independent rotations about two perpendicular axes in the mirror surface plane which intersect at the pole of the mirror and by linear motion along an axis orthogonal to the two rotation axes. These motions permit the surfaces of the three mirrors to lie on a common sphere, thereby forming the equivalent of a single mirror three times longer than any of the individual mirrors without the extreme cost and inherent figure error of such a lengthy mirror. The design is based on the combination of a double-axis gimbal mechanism and a linear extraction mechanism. Each mirror mechanism is fixed to a large rectangular flange attached to the mirror chamber by a special Helicoflex seal ∗∗ ∗∗ Helicoflex Company, 400 Myrtle Avenue, Boonton, NJ 07005, USA. . All motions for each of the three mirrors are provided by stepping motors through special mechanisms with three bellows, one for a two-axis rotation and two for linear motion.

A study of locomotor behavior in a captive colony of red-bellied lemurs (Eulemur rubriventer).

The considerable diversity of locomotor behavior within the suborder Prosimii largely is due to differences in locomotion between families. Within families, locomotion is relatively homogeneous, although some species, such as Otolemur crassicaudatus among the galagids and Hapalemur simus and Lepilemur spp. among the lemurids, differ from other species in their family. This paper describes the locomotion of a captive colony of red-bellied lemurs, Eulemur rubriventer (following the classification of Simons and Rumpler [1988] who place all species of Lemur other than Lemur catta in the genus Eulemur), another species whose movements differ markedly from other members of its family, the Lemuridae. Features that distinguish the locomotion of E. rubriventer from other lemurids are the high frequency of leaping, low frequency of climbing and suspension, and the use of head-downward vertical climbing in this species. Leaping is the most common form of locomotion in E. rubriventer. Horizontal, rather than vertical supports, are preferred during leaping. Although the frequency of climbing in this study is relatively low, the large brachioradialis flange, robust hallux, and claw-like nails of E. rubriventer suggest that clinging and climbing on large diameter vertical supports (lacking in the enclosures used in this study) may be an important component of locomotion in wild E. rubriventer and may reflect a gummivorous or insectivorous dietary adaptation. While the locomotion of E. rubriventer differs from all prosimians yet studied, the general pattern of locomotor behavior seen in this species is most similar to other species of the family Lemuridae.

Lateral buckling behaviour of monosymmetric plate girders

Abstract The results of a series of lateral buckling tests on approximately one-third scale models of steel bridge girders are presented. All specimens, which had unequal flanges, were carefully fabricated with controlled levels of residual stress due to welding and initial crookedness. The performance under load of each of the 12 specimens is discussed in some detail and the separate and combined effects of the different imperfection levels are identified. When considered in combination with all existing test data for laterally unrestrained beams, the present results confirm the need for a lower design curve for welder sections. They also suggest that special attention is required for welded sections with unequal flanges, where such beams are loaded with the larger flange in tension (termed LFT-monosymmetric sections).

Recent progresses of rolling technologies in Japan.

After the Plaza Agreement of G5, which was held in September 1985, the Yen was highly appreciated, and the Japanese government changed its policy from the encouragement of exports to the expansion of the domestic market. Fortunately, the government policy has been a success, and the production of hot and cold strip, large wide flange beam, wire and rod has recovered. Investment for equipment is under way and there are plans for renewing mills. However, the steel tube mills are highly dependent on the foreign market, the production of steel tube was drastically cut due to the sharp drop of the dollar and sharp rise of the yen. Nevertheless, research and development has been actively promoted and many marvelous results have been reported in every field. Iron and steel industries in Japan are still confident and innovative.

Problems with leakages at large flanges in the BASF new ammonia plant

AbstractLeakage from large diameter flanges had occurred several times in a new 1360 t/d ammonia plant. One such incident resulted in a large fire. The causes of this incident are examined.

Chronic fistulation and cannulation of the rabbit caecum.

A PTFE cannula was introduced into the rabbit abdomen through the right flank. A purse string suture was used to fix a small plastic flange within the caecum. A larger flange was sutured under the skin to fix the cannula. Caecal contents could be collected from the chronic fistula via a threaded stainless steel cap on the cannula. Animals tolerated the fistulation well and sepsis was never seen.

The humerus of Aegyptopithecus zeuxis: a primitive anthropoid.

Two complete humeri of Aegyptopithecus zeuxis have been recovered from Oligocene deposits in the Fayum Province of Egypt. These new specimens support previous interpretations of the locomotor adaptations of this species and indicate that A. zeuxis was a robust, slowly moving arboreal quadruped. While the previously described distal articular region of the humerus is virtually identical with the same region in many extant ceboids and the Miocene hominoid Pliopithecus vindobonensis, the more proximal parts of the humerus show many primitive "prosimianlike" features not found the limbs of extant anthropoids. The primitive features include the absence of a distinct deltoid plane, a broad shallow bicipital groove, a large brachialis flange, and an entepicondylar foramen. In most features, the humerus of Aegyptopithecus zeuxis is more primitive than the hypothetical last common ancestor of extant cercopithecoids and hominoids based on neontological comparisons. This supports other lines of evidence indicating that the hominoids from the Egyptian Oligocene are morphologically ancestral to both Old World monkeys and apes.

Nonlinear Stability and Tracking of Rail Passenger Trucks

An analysis of a rail passenger truck which includes nonlinear wheel/rail geometry and creep forces is formulated for determining truck stability and response to rail alignment irregularities. Digital simulation studies using the analysis have illustrated the large amplitude flange to flange response which occurs in operation of a truck below critical speed on a track with significant alignment irregularity, of a truck near critical speed and excited by irregularities and of a truck operated above critical speed. The variations in temporal waveform, probability density, and power spectral density of vehicle motions for these conditions are described. The influence of vehicle suspension parameters and wheel/rail geometry on truck stability and tracking ability is discussed and related to operating conditions.

Leak tight vacuum seals for large windows and flanges at liquid helium temperatures

current through the magnetized sample of 20 wt% in the two opposite directions which indicate asymmetry in the resistance of the sample (Fig. 1). Fig. 2 shows the temperature dependence of the reduced resistance, ie the ratio of the resistance at a given temperature (reduced against the critical temperature of the matrix) to the resistance in the normal state, for the sample containing 20 wt% ferromag. netic particles, both before and after magnetization for the both current directions. The estimated maximum errors of the measured values are shown in Fig. 2. As can be seen from Fig. 2, the values of the resistance measured with the current passing through the sample in the same direction as the magnetizating current are larger than the respective resistance values measured with the current passing in the opposite direction. The directional asymmetry of the electrical resistance has been found for aU circularly magnetized samples with the exception of the sample of 5 wt%.

The effect of calcar contact on femoral component micromovement. A mechanical study.

Extra-long-neck, large-stem Trapezoidal-28 femoral components with standard and modified large flanges were cemented into fresh cadaver femora and measurements were made of the movement of the prostheses relative to the bone as load was applied to the head of the prosthesis. In the presence of collar-calcar femoral contact, the prosthesis subsided very little under load; displacements for a load of 2000 newtons were less than 0.1 millimeter. Removal of bone and acrylic support beneath the undersurface of the flange by sawing a thin gap caused no increase in the displacement of the stem tip in most specimens, but the displacements of the collar relative to bone for the standard flange design increased by an average of 0.014 millimeter (8 to 28 per cent) under a 2000-newton force when contact was removed, while the displacements for the prostheses with a modified large flange that extended to the cortical rim of the resected neck increased 0.047 to 0.060 millimeter (56 to 432 per cent), indicating greater support from the collar due to the increased area of contact. An increase of the stem-flange angle of 22 degrees (from 30 to 52 degrees), making the flange more horizontal, had no significant effect on the results for large-flanged units. Prostheses with a standard flange and a one to two-millimeter Silastic liner between cement and bone subsided as much as twenty times more than rigidly cemented units. In the presence of the liner, removal of collar-calcar contact increased the collar displacement by 29 to 75 per cent, indicating a possibly important function of the flange for components cemented in soft bone or components that may become loose or be surrounded by a fibrous membrane. Repacking of the gap between the collar and bone with acrylic after removal of part of the calcar femoral reduced subsidence in one specimen, while the acrylic in a second specimen cracked out during reloading. Based on our laboratory experience with sixteen specimens, we believe that it would be extremely difficult to achieve an effective degree of uniform calcar femorale-collar contact at operation and that one or two localized contact areas would be the more common situation after total hip replacement.

Long-term middle ear ventilation.

Successful long-term middle ear ventilation was established in 12 patients with chronic eustachian tube hypofunction that had failed to respond to repeated myringotomy and tympanotomy tube insertions by conventional techniques. The 12 patients (13 ears) had insertion of an untrimmed large flange "Per-Lee" type tube through a posterior-inferior tympanomeatal flap approach. The flange extended under the long process of the malleus, and into the hypotympanum and middle ear opening of the eustachian tube. The stem of the tube was brought out through the inferior central pars tensa. All tubes have remained in place for more than three years without serious complications providing adequate middle ear ventilation and preventing adherence of the tympanic membrane to the promontory.

Large diameter cryogenic seals

Cryogenic vacuum seals are discussed with emphasis on large diameter reusable connections. Both theoretical considerations and experimental results are presented. The main subject is large diameter cryogenic vacuum seals in a horizontal vessel, where thermal distortions are encountered in particular during the cool down stage. We show a large diameter stainless steel flange design that can take large repeatable thermal shocks and maintain a good vacuum seal at liquid helium temperatures.

A Resonant Cavity Approach for the Nondestructive Determination of Complex Permittivity at Microwave Frequencies

A nondestructive microwave cavity approach for measuring complex permittivities of materials in sheet form is described. The resonant cavity is a section of a rectangular waveguide terminated by a thin rigid and large flange containing a small rectangular iris opening. The iris is placed in firm contact with one side of the dielectric sample while the other side is backed with a highly conducting plate. Variations of the cavity resonant frequency and Q-factor caused by the dielectric can be related to its complex permittivity through the consideration of equivalent admittance of this open-ended dielectricloaded aperture at resonance. Experimental determination of aperture admittance of a loaded iris is made and the results compared with theoretical calculations. The validity of this technique is confirmed by evaluating the resonant cavity characteristics by loading it with dielectrics of known permittivities and comparing the results with theoretical results. The permittivity of a lossy dielectric slab is measured and the value obtained by this method is compared with those found by other techniques. In all these cases the agreement between theory and measurements is satisfactory. Utility of this technique in evaluating the local inhomogeneities of permittivity of sheets is demonstrated. Measurement errors and limitations of this technique are pointed out.

A Point of View in Large Flanges Analysis

The paper introduces an analytical method for computing large flanges and an analog computer pattern for their simulation. Chapter I summarizes previous works in the field (Waters, et al., Murray and Stuart) to which a new analysis of the flange ring is proposed. Chapters II and III present EA C-technique of simulating stress-displacement dependence of a flange under external loads.

The Palatal Structure of some Canadian Hadrosauridae (Reptilia: Ornithischia): Reply

Two distinct hadrosaurian lineages can be delineated, each showing changes from possible hypsilophodont ancestors. The Hadrosaurinae are typified by moderately vaulted palates, broad pterygoid flanges, large anterior maxillary processes, and non-folded premaxillae, with direct narial passages. The Lambeosaurinae are characterized by highly vaulted palates, narrow pterygoid flanges, reduced anterior maxillary processes, and folded premaxillae and nasals with looped narial passages.Reconstruction of the palate indicates that the internal nares were displaced rearward, thus producing a structure similar to the secondary palate of mammals.The Constrictor Dorsalis group-muscles were well developed, allowing some minor lateral movement of the palate by slight torsion of the pterygoid. The large pterygoid flange would have prevented fore-and-aft movement of the palate.A reappraisal of the relationships between the lambeosaurine crests and the respiratory system indicates that the crests may have been used in dev...

The Palatal Structure of some Canadian Hadrosauridae (Reptilia: Ornithischia)

Two distinct hadrosaurian lineages can be delineated, each showing changes from possible hypsilophodont ancestors. The Hadrosaurinae are typified by moderately vaulted palates, broad pterygoid flanges, large anterior maxillary processes, and non-folded premaxillae, with direct narial passages. The Lambeosaurinae are characterized by highly vaulted palates, narrow pterygoid flanges, reduced anterior maxillary processes, and folded premaxillae and nasals with looped narial passages.Reconstruction of the palate indicates that the internal nares were displaced rearward, thus producing a structure similar to the secondary palate of mammals.The Constrictor Dorsalis group-muscles were well developed, allowing some minor lateral movement of the palate by slight torsion of the pterygoid. The large pterygoid flange would have prevented fore-and-aft movement of the palate.A reappraisal of the relationships between the lambeosaurine crests and the respiratory system indicates that the crests may have been used in developing individually recognizable calls. Previously unrecognized behavioural relationships may have been typical of these possibly endothermic animals.

The cytology of hofbauer cells

AbstractCytological investigation of Hofbauer cells in various stages of gestation reveals that they are similar to normal macrophages except for unusually large cytoplasmic flanges and included vacuoles. The system of vacuoles is apparently the result of macropinocytotic activity. The individual vacuoles undergo asymmetrical collapse in regions adjacent to small juxtavacuolar tubules thought to be derived from the agranular endoplasmic reticulum. In addition, coated micropinocytotic vesicles are common. Hofbauer cells thus appear to be a type of macrophage with an unusual capacity for fluid ingestion. In younger placentas, Hofbauer cells are usually associated with extracellular compartments within the stroma. These compartments are relatively free of collagen fibrils and demonstrable ground substance and are clearly demarcated from the rest of the stroma by processes of fibroblasts. The abundance of these cells in early placentas, their location in the stroma, and evidence of their pinocytotic activity suggest that these cells may play a role in removal of proteins from interstitial fluid. Hofbauer‐like cells were also studied in the guinea pig and the little brown bat. Of these two species, the Hofbauer‐like cells of the bat more closely resemble human Hofbauer cells in that they show evidence of extensive macropinocytotic activity.

Sealing Large Ultrahigh-Vacuum Flanges with Polytetrafluoroethylene Gaskets

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Sound Output of Nickel and Permendur Magnetostrictors under Static Compressive Stress

Relative sound output of bar magnetostrictors has been measured as a function of polarization at atmospheric stress and at a compressional stress of about 300 atm. Frequencies both at and well below the resonant frequency of the bar have been used. Thin laminations of nickel or permendur are glued together to form bars whose ends are then ground parallel. Each bar is length resonant at about 23 kcps. Half-wavelength brass stubs with large flanges at their centers are soldered to the bar and loosely mounted in cylinders. Air can be forced between the flanges and cylinder walls to apply compressive stress to the bar. The displacement of the end of one of the stubs is observed. For nickel, compressive stress increases sound output at low polarizations and decreases sound output at higher polarizations. Representative values are these: a compressive stress of 300 atm increases the resonant amplitude by 15% at a polarizing field of 20 oe and decreases it 15% at 70 oe. The polarization at which 300 atm compressive stress does not alter the resonant displacement is 45.3 oe. Displacements at 60 cps and at resonance are related by a theory involving the magnetostrictive constant and the reversible permeability, and there is good agreement between this theory and experiments. (This research was supported by the Office of Naval Research.)

The stress distribution near a loading point in a uniform flanged beam

The elementary theory of bending, which is the method by which the stresses in a uniform flanged beam subjected to transverse loading are usually determined, leads to certain incompatibilities of displacement and stress distribution near a section of the beam at which load is applied. The present paper endeavours to remedy these deficiencies. Two main cases are considered: that in which the beam is loaded through the web and that in which it is loaded through the flanges. In both of these the analyses lead to stress concentrations in the outer fibres of the flanges, and it is found that the maximum stress concentrations, which occur at the loading section, may be expressed with an accuracy sufficient for most engineering purposes by means of simple formulae. For both cases, maximum concentration factors occur in short beams having large flanges and thin webs. Results of strain-gauge tests carried out on mild steel beam specimens are presented which show very good agreement between the predicted and experimental stress distributions in the flanges, and a further part of the paper compares the present analyses with other recent work on the subject.