Blade End Research Articles

Réflexion autour de la fonction des retouchoirs en os de l’Aurignacien ancien

Bone retouchers are the most ancient osseous tools of the European Palaeolithic. They are very frequent on Mousterian sites and persist throughout the Upper Palaeolithic. Several functional analyses have been devoted to them and the most commonly accepted hypothesis proposed is their use for lithic tool retouching by percussion. However, this hypothesis is based mainly on studies of Mousterian pieces while few functional analyses have been undertaken on Upper Palaeolithic bone retouchers. The persistent presence of these “ ad hoc” tools makes their study important. This article presents the results of a techno-functional analysis devoted to the Early Aurignacian bone retouchers from Abri Castanet at Sergeac (Dordogne), northern and southern sectors (layer A and US 131 and below), Grotte des Hyènes at Brassempouy (Landes, complex 2) and Gatzarria at Suhare (Pyrénées-Atlantiques, layer cbcf). These unworked bone tools, including many specimens identified a posteriori among faunal remains, represent a significant part of the studied assemblages’ osseous equipment. There are two categories of retouchers : those on raw bone fragments and those on technical objects. The former, most numerous, are mainly long bone shaft fragments recovered after food operations and used just as they were, without modification. The latter correspond to the use of finished objects like smoothers and awls as well as manufacturing by-products. They bear diagnostic traces of utilisation in the form of linear, deep, short depressions, v-shaped in cross section. These depressions are similar to those that have been described in previous work involving microscopic observation and are compatible with use for lithic tool retouching by percussion. However, unlike Middle Palaeolithic retouchers, where the depressions are perpendicular to the main axis of the piece, Early Aurignacian depressions are often vertical (in combination or not with horizontal ones). This is a characteristic feature of Upper Palaeolithic retouchers related to their positions during use. The vertical depressions imply that the main axis of the retoucher is oriented parallel to the lithic edge during use. Quite obviously, this change in the functioning of retouchers must be linked to changes in flint-knapping processes. To understand this relationship, we explored the effects of changing the orientation of retouchers. One notable difference is their curvature in the transverse and longitudinal axes. The latter is clearly more pronounced than the former, meaning that the retouchers offer a greater overall surface area when used in a parallel orientation. We hypothesized that this orientation was preferred to increase the active surface of retouchers for the retouching of blade products. Indeed, during the Early Aurignacian, the manufacture of blade tools, scrapers in particular, often involved retouching very convex and narrow ends. Orienting the retoucher parallel to the lithic edge would have been a technical solution to compensate for the decrease in the active surface presented by the strong convexity of blade ends. However, within the Early Aurignacian lithic industry, blade ends are not the only items to show strong convexity : the fronts of carinated and nosed scrapers also display them. The use of retouchers in bladelet knapping has not so far been considered, but constitutes a second hypothesis that could explain the particular orientation of Early Aurignacian retouchers during use. T hese two assumptions have been tested by experimental replication. Results show that bone retouchers are effective tools for both blade retouching and bladelet knapping, provided that the weight of the retoucher is adjusted to suit the type of lithic product. In addition, lithic and bone tools produced experimentally fall within the range of variation observed in the archaeological assemblages studied. Finally, although this has not always been necessary, experimentation confirms the usefulness of parallel retoucher orientation to adapt the active surface areas to strong lithic convexity. To date, strong convexity of lithic products is the main factor likely to explain the change in retoucher orientation that occurred at least as early as the Early Aurignacian. Thus, retouchers of this period attest to the duration of an ancient technical process, involving the use of bone for stone knapping. Specimens bearing vertical depressions thus illustrate the adaptation of the retouchers to “ new” lithic technologies. The important role played by retouchers in retouching Mousterian tools and their number within the assemblages studied leave little doubt as to their use in retouching Upper Palaeolithic blade products. However, it is still difficult to determine whether they were in fact used in bladelet knapping. The traces of utilisation on experimental retouchers are quite similar to those on specimens used in blade retouching. An expanded experimental program and analysis of the bone tools with high magnification should facilitate the assessment of morphometric changes in use-wear traces based on activity. In addition, a comparison of technical and functional characteristics of archaeological and experimental lithic products should help clarify the array of hammers used during the Aurignacian.

Determination of the influence of a clearance between the case and blade ends of the semi-open impeller on the centrifugal compressor stage characteristics

The influence of the clearance between the case and blade ends of the semi-open impeller on the centrifugal stage characteristics is considered using the experimental data and numerical calculation results.

Effect of ractopamine level, gender, and duration of ractopamine on belly and bacon quality traits

The objective was to determine belly and bacon quality traits in pigs fed ractopamine (RAC) for various durations during finishing. A 2 × 3 × 2 factorial arrangement was used with barrows and gilts, fed RAC levels of 0.0, 5.0, or 7.4 ppm, for 21 or 28 d prior to harvest. Bellies were fabricated and measured for length, thickness, firmness, and processing yields. Once processed, 1.27 cm slices were removed at 25%, 50%, and 75% the distance from the blade end, packaged and digitally imaged using a Chem1 Genius 2 Bio Imaging System. Total slice area (TA), total slice length (TL), secondary lean length (SL), secondary lean area (SA), and percent lean area (TA – all lean components = LA) were determined by tracing images in Adobe Photoshop Elements. A composite sample from the three slices was used for proximate analysis to determine moisture and fat composition for each belly. Feeding RAC increased belly yield, TA, TL, SA, and LA ( P < 0.05), but did not alter moisture or fat composition ( P > 0.05). Gilts had decreased firmness and higher pump uptakes compared to barrows ( P < 0.05). Additionally gilts had increased TL, SL, and LA with lower fat and higher moisture content ( P < 0.05). RAC feeding duration had no significant effect on belly or bacon quality traits ( P > 0.05), furthermore, no interactions were found to be significant ( P > 0.05). RAC administration during finishing resulted in improved belly and bacon yields with no negative effects on the quality traits evaluated.

Aerodynamic Design, Model Test, and CFD Analysis for a Multistage Axial Helium Compressor

Results of an aerodynamic design study for the multistage axial helium compressor of a 300 MWe class nuclear gas turbine are presented. Helium compressor aerodynamics is challenged by the characteristically narrow and numerous-stage flow path, which enhances loss effects of blade surface and end wall boundary layer growth, secondary and clearance flows, and any occurrence of flow separation and stage mismatch. To meet the high efficiency and reliability requirements of the nuclear application, base line and advanced aerodynamic design techniques are incorporated with the intent to mitigate the flow path adverse working condition and losses. Design validation is carried out by test and test-calibrated 3D viscous CFD analyses of a subscale model compressor. In addition to verifying the success of the design intent, the data and computational insights of overall performance and internal flow behavior are used to establish a performance model based on Reynolds number and used for the full compressor performance prediction. The model applicable to all geometrically similar designs shows sensitive responses of helium compressor aerodynamic efficiency to Reynolds number and surface roughness. Presented in the paper is the first modern design with experimental validation for multistage axial helium compressor that concerned itself with a difficult past but which has strong current interest in countries now developing thermal and fast nuclear gas reactors.

Study the Effect of Errosion on the Breakage of Steam Turbine Blade at Baiji Power Station

The last stage endured on obvious erosion especially the front and the end of the blade. The erosion caused the appearance some cracks in this place. These remarks coincided with the theoretic al results, which were acquired according to the condition of the turbine of station which showed that the droplet, which collided with the blade ends, caused high pressure on the surface of the blade and caused the occurrence of the corrosion. The danger of the erosion unavoidable due to its relationship with tae station efficiency and the only to avoid that is the use of the blade made of erosion resistance ingots.

Control of Three-Dimensional Separations in Axial Compressors by Tailored Boundary Layer Suction

One of the important ways of improving turbomachinery compressor performance is to control three-dimensional (3D) separations, which form over the suction surface and end wall corner of the blade passage. Based on the insights gained into the formation of these separations, this paper illustrates how an appropriately applied boundary layer suction of up to 0.7% of inlet mass flow can control and eliminate typical compressor stator hub corner 3D separation over a range of operating incidence. The paper describes, using computational fluid dynamics, the application of suction on the blade suction surface and end wall boundary layers and exemplifies the influence of end wall dividing streamline in initiating 3D separation in the blade passage. The removal of the separated region from the blade suction surface is confirmed by an experimental investigation in a compressor cascade involving surface flow visualization, surface static pressure, and exit loss measurements. The ensuing passage flow field is characterized by increased blade loading (static pressure difference between pressure and suction surface), enhanced average static pressure rise, significant loss removal, and a uniform exit flow. This result also enables the contribution of the 3D separation to the overall loss and passage blockage to be assessed.

Vibration of Steam Turbine Blade Caused by Shock Load due to Partial Admission

Partial admission has been applied to the control stage of steam turbine because it produces high turbine efficiency at low loads. The shock load caused by partial admission generates excitation force on a blade, and the vibratory stress of the blade may become a cause of HCF (High Cycle Fatigue). Therefore, in designing a control stage blade of steam turbine, the vibratory stress caused by partial admission should be exactly predicted. Recently, ISB (Integral Shroud Blade) structure has been applied to not only the low-pressure end blade but also the control stage blade of steam turbine. Because the traditional analysis method based on experiments can predict only the vibratory stress of the grouped blade structure, it is indispensable to develop the general analysis method of vibratory stress caused by shock load, which can be applied to both of the grouped blade and ISB structure. This paper, first, presents the analysis method for the grouped blade and ISB structure to calculate the vibratory stress caused by partial admission. Second, the vibration response characteristics to shock load is explained, using some calculated results of simplified blade models. Finally, the response analysis is carried out for the actual grouped blade and ISB structure, and the results are evaluated from the viewpoint of blade reliability.

Effect of proton beam profile on stress in JSNS target vessel

A cross-flow type (CFT) mercury target with flow guide blades has been developed for JSNS that suppresses the generation of a stagnant flow region near the beam window where the peak power density is generated due to the spallation reaction. In addition, a flat type beam window has been applied to the CFT target that suppresses dynamic stress caused by pressure waves, that have been estimated with an elastic model for mercury. Recent experimental results obtained by using a proton beam incident to mercury targets suggested that using a cut-off pressure model for mercury would be appropriate for predicting a dynamic stress behavior in a target vessel. Dynamic stress analyses were carried out with the cutoff pressure model in which the negative pressure less than −0.15 MPa could not be sustained. The dynamic stress generated in the flat beam window became much larger than that in a semi-cylindrical type window as a result of using the cut-off pressure model. Regardless, even the stress generated in the semi-cylindrical type beam window exceeded the allowable stress of SS316L under the peak power density of 668 MW/m 3. In order to decrease the dynamic stress in the semi-cylindrical beam window, the incident proton beam was defocused to reduce the peak power density down to 218 MW/m 3. Although the dynamic stress could be suppressed to less than the allowable stress, the high power density generated on the end of the flow guide blades due to defocus of the proton beam caused high thermal stress exceeding the allowable stress. Several shapes of blade ends were studied analytically to decrease the thermal stress, that did not affect the mercury flow distribution. A simple thin-end blade showed low thermal stress below the allowable stress.

Clinical pearl TN3–abracketpositioninginstrument

Positioning orthodontic brackets is a task most clinicians like to do as quickly and accurately as possible. When using the direct bonding technique the choice of instruments is either a measuring device or one of several hand-held dental instruments not usually designed for the task, ranging from a flat plastic to a probe. The TN3 TM bracket positioning instrument* was designed specifically for the purpose of positioning orthodontic brackets and cleaning up the excess composite. It is a simple double-ended hand held instrument (Figure 1) with a bracket positioning blade at one end and a composite cleaning end at the other. It enables the operator to quickly manipulate the orthodontic brackets into the ideal position on the tooth, and then by turning the instrument around allows the excess composite to be removed. Once the bracket is placed on the tooth it can easily be manipulated into the desired position using either the tip (Figure 2) or the lower edge of the blade (Figure 3) located within the bracket slot. Once the bracket is in the desired position it is compressed against the tooth surface to express any excess adhesive from under the bracket. The ‘TN3’ can be used to manipulate brackets with either an 0.018’’ or 0.022’’ slot without binding in the slot when lifted away because the ‘TN3’ blade is parallel sided. The 45u angulation of the blade end of the instrument allows the operator to use the tip of the blade to manipulate brackets on the anterior and premolar teeth, as well those displaced from the line of the arch (Figure 2).

A new species of Sphaerodoropsis (Polychaeta: Sphaerodoridae) from north-east Atlantic, with comments on other species of the genus

A new species of sphaerodorid (Polychaeta: Sphaerodoridae), Sphaerodoropsisgarciaalvarezi sp. nov., is described from specimens collected on sandy bottoms off the Galician coast (Spain, north-east Atlantic). This species is characterized by having two pairs of digitiform lateral antennae, 13 dorsal macrotubercles per segment in mid-body setigers arranged in two transverse rows, five dorsal microtubercles per segment arranged in five longitudinal rows, six ventral papillae per segment arranged in six longitudinal rows, digitiform presetal lobes and ventral cirri, and composite setae with spinulation on blade and distal end of shaft. Complementary observations to original descriptions are also provided for closely related species Sphaerodoropsis bisphaeroserialis and Sphaerodoropsisarctowskyensis upon examination of type series.

深層混合処理工法の掘削攪拌性能に関する研究(材料施工)

The author have developed a plate-type mechanical blade system attached to static blade end, aiming at rational mixier arrangement. In this paper, the unconfined compression strength and vertical capacities of mixer were experimentally investigated for various of loams. As the results, it is verified that the construction quality of the mixer can be evaluated with the generalized superposed sterngth theorem and their high quality are satisfactory against loams.

Stress Redistribution for Increased Creep Life in the GE MS6001 B Second-Stage Blade

When a hot end blade for a gas turbine is designed, several failure criteria must be considered to insure reliability. The criteria include (but are not limited to) creep rupture, low-cycle fatigue, high-cycle fatigue, and creep deflection. This paper will focus on the second-stage turbine blade for the GE MS6001 industrial gas turbine. BP Amoco has experienced failure of this blade due to excessive creep deflection. Creep deflection rate is a function of stress level and metal temperature. A typical approach to reducing creep deflection is to reduce the bulk temperature in the blade. In this paper a design is reviewed that has had the stress redistributed, so that the high-temperature regions of the airfoil are at a lower stress level, thereby reducing the creep rate to an acceptable level.

Analysis of wearing-out causes for revolving-blade mixers and their reliability improvement

Abstract In road coverings and structures of transport infrastructure, composite mixes of various compositions are used made with either organic or mineral binding agents. Most often they are made in a discreet revolving-blade forced mixer, and the final product quality is subject to the mixer construction and parameters. The present paper analyzes wear causes of a revolving-blade mixer with the most important of them-sticking of grains between the blade end and the bottom. Forces are defined effecting various-sized grains found between the blade end and the mixer bottom. Mixer quality assessment methodology is presented, based on analysis principles of homogeneity dynamics for mix being made by it. It is demonstrated that construction homogeneity estimates are different for mixers with various wearing-out levels. Wearing- out of mixer elements may be reduced and mixing quality for mix may be improved by choosing the optimum distance between the blade end and the bottom fretting and changing blade metal a...

ANALYSIS OF WEARING-OUT CAUSES FOR REVOLVING-BLADE MIXERS AND THEIR RELIABILITY IMPROVEMENT

In road coverings and structures of transport infrastructure, composite mixes of various compositions are used made with either organic or mineral binding agents. Most often they are made in a discreet revolving-blade forced mixer, and the final product quality is subject to the mixer construction and parameters. The present paper analyzes wear causes of a revolving-blade mixer with the most important of them-sticking of grains between the blade end and the bottom. Forces are defined effecting various-sized grains found between the blade end and the mixer bottom. Mixer quality assessment methodology is presented, based on analysis principles of homogeneity dynamics for mix being made by it. It is demonstrated that construction homogeneity estimates are different for mixers with various wearing-out levels. Wearing- out of mixer elements may be reduced and mixing quality for mix may be improved by choosing the optimum distance between the blade end and the bottom fretting and changing blade metal and dimensions. Elastic centrifugal coupling is recommended to decrease transmission strokes.

End Scraper Reduction and Hunter-Gatherer Mobility

Various lithic measures have been invoked to argue that human foragers moved over greater or lesser distances, or moved with greater or lesser frequency when compared with other foraging groups. This paper examines one of those measures—the reduction of blade end scrapers from early Upper Paleolithic Aurignacian and Perigordian occupations in southwestern France. Evidence of end scraper reduction is compared with faunal diversity and lithic material provenience, the former a potential catalyst of and the latter a potential reflection of mobility. A relationship between less-intense end scraper reduction, somewhat elevated percentages of distant raw materials, and reindeer-dominated fauna is noted during cold and apparently open environmental conditions. Less consistency in the extent of end scraper reduction is observed among assemblages associated with more diverse and at times less-mobile fauna. These observations argue for the importance of a fine-grained comparison of lithic and other data, the complexity of procurement strategies, and the recognition that greater or lesser reduction does not translate directly into greater or lesser mobility.

643 蒸気タービン長翼の振動応力の解析と計測

643 蒸気タービン長翼の振動応力の解析と計測

Development of New Advanced Low Pressure End Blades for High Efficiency Steam Turbine.

A low pressure end blade is one of the most important elements in designing the steam turbine, because it determines the performance, the dimension, and the number of casings of the turbine. Applying the state of the art technology to the aerodynamic and mechanical design, Mitsubishi Heavy Industries, Ltd. has been conducting a development program of new advanced low pressure end blades which adopt the ISB (Integral Shroud Blade) structure. A new standard series of these low pressure end blades has already been completed for 50 Hz and 60 Hz unit application including 3 600 rpm 45 inch titanium blade, 3 000 rpm 48 inch steel blade, and 1500/1800 rpm 54 inch steel blade which have the largest exhaust annulus area among the same class blades in the world. This paper reports on the up-to-date design technology applied to the new advanced low pressure end blades and on the verification tests to ensure the high efficiency and the reliability of the developed blades

P13-05 高効率・高信頼性タービン長大翼の開発

P13-05 高効率・高信頼性タービン長大翼の開発

Archaeological Investigation of an Oil Well Pad Disturbance at the Tom Moore Site (41PN149), Panola County, Texas

The Tom Moore site (41PN149) is situated on the east slope of a circular-shaped landform at the highest point of a steeply-sloping upland in the Irons Bayou valley in Panola County, Texas. Irons Bayou, 1.2 km to the west of the site, flows east to its confluence with the Sabine River. A small tributary of Irons Bayou is 600 m to the south. Soils here are a brown sandy loam overlying a very hard red clay B-horizon. Like most of East Texas, the land has been farmed previously, as indicated by old plow furrows, and it has reforested naturally in pine and mixed hardwoods in the last 30 years. The site's upland setting is similar to other Middle Caddoan sites in the Sabine River basin in East Texas. An oil field employee, J. W. Golden of Kilgore, Texas, located the Tom Moore site. He noticed a cache of seven large celts that had been disturbed by construction equipment preparing a well site. The oil well construction consisted of two wells and three associated storage tanks. Approximately 2 acres had been disturbed during the leveling process, and part of the hill was used to form the level well pad. A cultural resources management survey had not been required by the Railroad Commission of Texas prior to construction. Mr. Golden described the celts as occurring in a group with the blade ends up. The heavy equipment had grazed them and caused some damage. He collected the celts and informed the authors. We visited the site, made a surface collection, noted a midden area at one end of the disturbance, and collected soil samples for flotation (these materials were submitted to S. Eileen Goldborer of Paleoethnobotanical Services, Austin, Texas) as well as OCR dates. No testing was conducted by the authors to determine the extent of the site. A small, circular mound is located in the wooded area adjacent to the well pad.

Viscous Throughflow Modeling of Axial Compressor Bladerows Using a Tangential Blade Force Hypothesis

This paper describes the modeling of axial compressor blade rows in an axisymmetric viscous throughflow method. The basic method, which has been reported previously, includes the effects of spanwise mixing, using a turbulent diffusion model, and endwall shear within the throughflow calculation. The blades are modeled using a combination of existing two-dimensional blade performance predictions for loss and deviation away from the annulus walls and a novel approach using tangential blade forces in the endwall regions. Relatively simple assumptions about the behavior of the tangential static pressure force imposed by the blades allow the secondary deviations produced by tip clearance flows and the boundary layer flows at fixed blade ends to be calculated in the axisymmetric model. Additional losses are assigned in these regions based on the calculated deviations. The resulting method gives realistic radial distributions of loss and deviation across the whole span at both design and off-design operating conditions, providing a quick method of estimating the magnitudes of these effects in the preliminary design process. Results from the method are compared to measured data in low and high-speed compressors and multistage three-dimensional viscous CFD predictions.