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An experimental investigation of the unsteady problem for a thin, symmetric airfoil exposed to periodic gusting was performed in a free-jet anechoic wind-tunnel fadlity. The gusting events were created upstream such that there was a small longitudinal, i.e., spanwise, wave number and the gust could be approximated as two dimensional. Measurements of the unsteady velocity field, the unsteady pressure at the airfoil surface, and the acoustic field were made for two values of axial and normal reduced frequency. The unsteady pressure distribution along the airfoil was computed using the Sears method and unsteady velocity data. In addition, the pressure distribution was computed using acoustic data as input to a numerical inversion technique. The results of each technique were compared with the experimentally obtained unsteady pressure distribution. The inversion technique showed good agreement with the Sears method. However, comparison with experimental results illustrated that the theoretical estimates, although exhibiting trends similar to the experimental data, consistently underestimated the experimental unsteady pressure distribution at the lower reduced frequency, indicating the presence of viscous effects. Better agreement between experimental and theoretical results was obtained at the higher reduced frequency where viscous effects were less prominent.

Spatially oriented segmentation allows researchers to break down the continuous stream of the ongoing EEG into microstates with stable topography of the brain electrical landscapes. The resulting microstates were shown to be related to conscious mental experience as well as to psychiatric disorders typically associated with thought disorders. In the present study, the microstates of the resting EEG of patients presenting with mild or moderate probable dementia of the Alzheimer type (DAT) were investigated. A significant anteriorisation of the centers of gravity of the microstate fields, an increase of the microstates' optimal window size and a reduced duration of sustained microstates were found. These differences were statistically more robust than the typical changes in the frequency domain (diffuse slowing) and were significantly correlated with the cognitive decline. The adaptive spatial segmentation into microstates is discussed as a method to extract meaningful EEG parameters for the early diagnosis and staging of Alzheimer's disease.

Noise radiation from a four bladed, 10 in. diameter propeller operating in air at a rotational speed of 3000 RPM and a freestream velocity of 33 ft/s was experimentally analyzed using hot-wire and microphone measurements in an anechoic wind tunnel. Turbulence levels from 0.2 to 5.5% at the propeller location were generated by square-mesh grids upstream of the propeller. Autobicoherence measurements behind the blade trailing edges near the hub and tip showed regions of high phase-coherence between the blade-passage harmonics and the broadband frequencies. Inflow turbulence reduced this coherence. By relating the fluctuation velocities in the propeller wake to the unsteady blade forces, the primary regions of tonal noise generation have been identified as the hub and tip regions, while the midspan has been identified as a region responsible for broadband noise generation. These measurements were complimented by cross-spectra between the propeller wake-flow and the measured sound. The effect of turbulence on the radiated noise level showed an overall increase of 2 dB in the broadband levels for every 1% increase in turbulence. This effect varied for different frequency bands in the acoustic spectrum.

Background Forced displacement related to persecution and violent conflict has reached a new peak in recent years. The primary aim of this study is to provide an initial overview of the acute and chronic health care problems of asylum seekers from the Middle East, with special emphasis on asylum seekers from Syria. Methods Our retrospective data analysis comprised adult patients presenting to our emergency department between 01.11.2011 and 30.06.2014 with the official resident status of an “asylum seeker” or “refugee” from the Middle East. Results In total, 880 patients were included in the study. Of these, 625 (71.0%) were male and 255 (29.0%) female. The median age was 34 (range 16–84). 222 (25.2%) of our patients were from Syria. The most common reason for presentation was surgical (381, 43.3%), followed by medical (321, 36.5%) and psychiatric (137, 15.6%). In patients with surgical presentations, trauma-related problems were most common (n = 196, 50.6%). Within the group of patients with medical presentation, acute infectious diseases were most common (n = 141, 43.9%), followed by neurological problems (n = 70, 21.8%) and gastrointestinal problems (n = 47, 14.6%). There were no differences between Syrian and non-Syrian refugees concerning surgical or medical admissions. The most common chronic disorder of unclear significance was chronic gastrointestinal problems (n = 132, 15%), followed by chronic musculoskeletal problems (n = 108, 12.3%) and chronic headaches (n = 78, 8.9%). Patients from Syria were significantly younger and more often suffered from a post-traumatic stress disorder than patients of other nationalities (p

Interest in the design of small, efficient, radio-controlled aircraft began with model airplanes in the 1930s and continues to this day because of the developments in sensors and actuators for a wide variety of small unmanned aerial vehicles. The combination of small scale and low velocities results in a flight regime with low chord Reynolds numbers. The range of chord Reynolds number from about 60000 to 200000 is of particular interest. The design of airfoils in the low Reynolds number regime and the experimental validation of these designs are discussed in this chapter. The design and performance of low aspect ratio (LAR) wings for micro air vehicle (MAV) applications including the effect of camber have been discussed. Examples of the application of LAR wings to the design of rigid and flexible fixed wing MAVs are presented. Keywords: laminar separation bubble; transition and reattachment; airfoil and wing design; validation of design; low aspect ratio wings; micro air vehicles; flexible wings; camber; endplates

To further explore the reactivity of the (C(5)Me(5))(-) ligand in the sterically crowded (C(5)Me(5))(3)M complexes, reactions with PhEEPh (E = S, Se, Te) have been examined. With M = La, Pr, Nd, Sm, and Y, PhSSPh reacts to form the expected reduction products, [(C(5)Me(5))(2)M(SPh)](2), but the major organic byproduct is not the sterically induced reduction product, (C(5)Me(5))(2). Instead, the sigma bond metathesis product, C(5)Me(5)SPh, is the major byproduct. In contrast, reactions with (C(5)Me(5))(3)Ce and (C(5)Me(5))(3)U gave a mixture of C(5)Me(5)SPh and (C(5)Me(5))(2) as byproducts. PhSSPh reactions with the lanthanide nitrile adducts, (C(5)Me(5))(3)Ln(NCCMe(3))(2) (Ln = La, Ce) and (C(5)Me(5))(3)Nd(NCCMe(3)), formed [(C(5)Me(5))(2)Ln(SPh)(NCCMe(3))](2) and only C(5)Me(5)SPh as the byproduct. PhSeSePh reactions paralleled the PhSSPh results, but reactions of PhTeTePh with (C(5)Me(5))(3)La, (C(5)Me(5))(3)Sm, and (C(5)Me(5))(3)La(NCCMe(3))(2) gave only (C(5)Me(5))(2) as a byproduct.

Experiments were concluded with two identical Wortmann FX63-137 airfoils in closely coupled tandem configurations at a Reynolds number of 8.5 x 10 4. For the data presented here, the values of the stagger and gap were 1.5 and 0, respectively. The decalage angles were 0 and ±10 deg. Direct measurement of lift, drag, and 1/4-chord pitching moment, as well as static pressure distributions, were acquired for each airfoil. Flow visualization using kerosene smoke was performed to complement the experimental data. The total drag reduction and lift increase resulted in a significant increase in the lift-to-drag ratio for a number of configurations. Nomenclature Aw = wing area Cd = section drag coefficient, D/(Awqx) Ci = section lift coefficient, L/(AwqJ) Cm = section 1/4-chord moment coefficient, Cp = pressure coefficient, l-q/qx c = chord length D = drag force G = gap, \y\lc L = lift force M = 1/4-chord pitching moment q = dynamic pressure, \pU2 Rc = Reynolds number based on chord, Uxc/v St = stagger, x/c (positive when upstream airfoil is above the downstream airfoil) U = flow velocity x = distance in streamwise direction y - distance normal to streamwise directions a = angle of attack 8 = decalage, aua - ada

The rheologic properties of senescent erythrocytes have been examined using two models of red blood cell (RBC) aging. In the rabbit, aged erythrocytes were isolated after biotinylation, in vivo aging, and subsequent recovery on an avidin support. Aged RBCs from the mouse were obtained using the Ganzoni hypertransfusion model that suppresses erythropoiesis for prolonged periods of time allowing preexisting cells to age in vivo. In both cases, the aged erythrocytes were found by ektacytometry to have decreased deformability due to diminished surface area and cellular dehydration. The aged rabbit erythrocytes were further characterized by micropipette methods that documented an average surface area decrease of 10.5% and a volume decrease of 8.4% for the cells that were 50 days old. Because both the surface area and volume decreased with cell age, there was little change in surface-to- volume ratio (sphericity) during aging. The aged cells were found to have normal membrane elasticity. In addition, human RBCs were fractionated over Stractan density gradients and the most dense cells were found to have rheologic properties similar to those reported for the aged RBCs from rabbits and mice, although the absolute magnitude of the changes in surface area and volume were considerably greater for the human cells. Thus, stringent density fractionation protocols that result in isolation of the most dense 1% of cells can produce a population of human cells with rheologic properties similar to senescent cells obtained in other species. The data indicate that progressive loss of cell area and cell dehydration are characteristic features of cell aging.

The limits of steric crowding in organometallic metallocene complexes have been examined by studying the synthesis of [(C(5)Me(5))(3)ML(n)] complexes as a function of metal in which L=Me(3)CCN, Me(3)CNC, and Me(3)SiCN. The bis(tert-butyl nitrile) complexes [(C(5)Me(5))(3)Ln(NCCMe(3))(2)] (Ln=La, 1; Ce, 2; Pr, 3) can be isolated with the largest lanthanide metal ions, La(3+), Ce(3+), and Pr(3+). The Pr(3+) ion also forms an isolable mono-nitrile complex, [(C(5)Me(5))(3)Pr(NCCMe(3))] (4), whereas for Nd(3+) only the mono-adduct [(C(5)Me(5))(3)Nd(NCCMe(3))] (5) was observed. With smaller metal ions, Sm(3+) and Y(3+), insertion of Me(3)CCN into the M--C(C(5)Me(5)) bond was observed to form the cyclopentadiene-substituted ketimide complexes [(C(5)Me(5))(2)Ln{NC(C(5)Me(5))(CMe(3))}(NCCMe(3))] (Ln=Sm, 6; Y, 7). With tert-butyl isocyanide ligands, a bis-isocyanide product can be isolated with lanthanum, [(C(5)Me(5))(3)La(CNCMe(3))(2)] (8), and a mono-isocyanide product with neodymium, [(C(5)Me(5))(3)Nd(CNCMe(3))] (9). Silicon-carbon bond cleavage was observed in reactions between [(C(5)Me(5))(3)Ln] complexes and trimethylsilyl cyanide, Me(3)SiCN, to produce the trimeric cyanide complexes [{(C(5)Me(5))(2)Ln(mu-CN)(NCSiMe(3))}(3)] (Ln=La, 10; Pr, 11). With uranium, a mono-nitrile reaction product, [(C(5)Me(5))(3)U(NCCMe(3))] (12), which is analogous to 5, was obtained from the reaction between [(C(5)Me(5))(3)U] and Me(3)CCN, but [(C(5)Me(5))(3)U] reacts with Me(3)CNC through C--N bond cleavage to form a trimeric cyanide complex, [{(C(5)Me(5))(2)U(mu-CN)(CNCMe(3))}(3)] (13).

The limits of steric crowding in tris(pentamethylcyclopentadienyl) complexes have been expanded by isolation of the first compound with this ligand set and two additional ligands, (C(5)Me(5))(3)ML(2). This result was obtained in a study of the effect of added ligands on the reactivity of sterically crowded (C(5)Me(5))(3)La, 1. Although neither THF nor Ph(3)PO formed crystallographically characterizable (C(5)Me(5))(3)LaL(x) complexes with 1, these (C(5)Me(5))(3)La/L(x) mixtures displayed enhanced reactivity compared to 1 with substrates such as C(8)H(8) and CO(2). Attempts to use adamantyl azide, AdN(3), to make (C(5)Me(5))(3)LaL(x) complexes led to the first example of azide insertion into a metal cyclopentadienyl linkage to generate (C(5)Me(5))(2)La[eta(2)-(N,N')-(C(5)Me(5))NN'N''Ad](N(3)Ad). Addition of Me(3)CCN to 1 produced the first crystallographically characterized (C(5)Me(5))(3)ML(2) complex, (C(5)Me(5))(3)La(NCCMe(3))(2).

The effects of an accelerating freestream from a nonzero velocity on the transitional separation bubble characteristics were investigated quantitatively. Hot wire anemometry was used to determine the boundary layer velocity profile repsonse to the acceleration at selected chordwise locations on a Wortmann FX 63-137 airfoil at 7 ° angle of attack. Both positive and negative accelerations were studied from base chord Reynolds number of 100,000 and 150,000, respectively. The purpose of this experiment was to verify the trends witnessed in previous research concerning a sinusoidally oscillating freestream velocity by uncoupling the accelerating and decelerating boundary layer effects. The experimental results indicate that as a result of a freestream acceleration, the separation bubble position shifts in the direction opposite to the chordwise direction it would move for a quasi-steady velocity change. The transition location was more responsive to the acceleration than was the separation position. This supports the oscillating freestream experiment conclusions.

From this study of three quite different viscous separated flow problems using the same numerical techniques, it is apparent that experimentation is as important in the numerical sense as it is in the physical sense. The time-depen dent conservative equations with upwind differencing for advection terms produced stable solutions over a wide range of Reynolds numbers. The actual accuracy of the numerical solutions varied with the flow problem and mesh geometry. A variable mesh, concentrating mesh points in regions of steepest gradients, appears to be a convenient method of reducing the, ever present, artificial viscosity effect. Numerical solutions with engineering accuracy can be obtained if great care is taken to control this artificial viscosity effect. Furthermore, they allow the study of basic flow phenomena which would be more difficult to produce and study in physical experiments. These methods, however, are still in the developmental stages and are not available in foolproof form for use by design engineers.

Transforming growth factor-beta is a potent immune suppressor that is over expressed by most malignant cells to evade the host immune response. Thus, a potential anticancer therapeutic strategy is the inhibition of transforming growth factor-beta signaling.We investigated the specificity and the antitumor effect of IN-1130, a novel small molecule inhibitor of the transforming growth factor-beta type I receptor ALK-5.IN-1130 inhibited transforming growth factor-beta induced cell death and gene transcriptional activity in a concentration dependent manner in the human hepatoma cell line HepG2. Simultaneously immunoblot analysis demonstrated that IN-1130 inhibited the Smad2 phosphorylation induced by transforming growth factor-beta. To determine the specificity of IN-1130 for transforming growth factor-beta signaling the effect on active and bone morphogenic protein signaling was subsequently investigated. Results demonstrated that IN-1130 did not inhibit bone morphogenic protein signaling. However, active signaling was blocked by IN-1130 in a concentration dependent manner. Furthermore, immunoblot analysis for phospho-Smad2 following transfection with constitutively active ALK-1 to 7 demonstrated that IN-1130 inhibited ALK-4 (active receptor type IB), 5 (TbetaRI) and 7 (nodal type I receptor). To investigate the antitumor effect of IN-1130 WT mice were injected subcutaneously with the murine prostate cancer cell line Tramp C2. Seven days later IN-1130 was administered intraperitoneally daily for 30 days. Results demonstrated a dramatic decrease in tumor volume in association with an enhanced immune response in the treatment group.Taken together these results demonstrate that IN-1130 is a relatively nontoxic inhibitor of ALK-4/5/7 that may potentially treat prostate cancer.

Summary A variant of Band 3, the major protein of the erythrocyte membrane, was observed by Mueller and Morrison in 1977 in 6–7% of healthy blood donors on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS–PAGE) of erythrocyte membranes treated with pronase. Pronase treated red cells containing this first recognized variant [here designated ‘Band 3-Memphis (m)’]§ had two bands of about 63000 and 60000 Mr while pronase treated normal cells had only the lighter Mr band. The present study includes data on the frequency of variants resembling Band 3-Memphis in patients of different ethnic groups and on random donors obtained earlier in Memphis. These variants were detected by the original method of Mueller and Morrison and were not associated with recognized clinical or haematological abnormalities. Significantly higher gene frequencies for the variants of the (m) type were observed in American Indians, African Americans and Filipinos than in Caucasians: putative heterozygotes and homozygotes were identified among each of these groups. The frequency of silent Band 3 polymorphisms in different populations should be considered in the interpretation of clinical findings associated with the presence of Band 3 variants.

An experimental investigation was conducted to measure the reverse flow within the transitional separation bubble that forms on an airfoil at low Reynolds numbers. Measurements were used to determine the effect of the reverse flow on integrated boundary-layer parameters often used to model the bubble. Velocity profile data were obtained on an NACA 663-018 airfoil at angle of attack of 12 deg and a chord Reynolds number of 140,000 using laser Doppler and single-sensor hot-wire anemometry. A new correlation is proposed based on zero velocity position, since the Schmidt (1986) correlations fail in the turbulent portion of the bubble.

Spatial and temporal characteristics of lexico-semantic retrieval are frequently examined with semantic context (i.e., priming) paradigms. These paradigms measure context (i.e., priming) effects in word processing evoked by semantically related context. Besides the well-known attention-dependent N400 context effect (250 ms), recent studies demonstrate early automatic context effects in the P1-N1 time period (200 ms). However, in visual word presentation the semantic origin of these early effects remains debated. This study examined spatio-temporal activation dynamics of the early context effect as well as the modulation of the effect by differences in structure and accessibility of verbal semantics existent in abstract and concrete words. The early context effect was measured in visually displayed words that followed semantically related single-word context. Spatial and temporal aspects of the effect were analyzed by applying topographic and source analyses on the word-triggered Event Related Potentials. The early context effect was enhanced in abstract compared to concrete words as indicated by a difference in the occurrence of P1-N1 transition map and a corresponding topographic dissimilarity (116-140 ms). This concreteness-dependent modulation demonstrates the sensitivity of the early context effect to structural differences in verbal semantics. Furthermore, the topographic difference was explained by enhanced activation in the left inferior prefrontal cortex for related compared to unrelated words in addition to temporo-parietal generators recruited in both conditions. The result suggests automatic feedforward processing of context-related information in temporo-prefrontal brain regions critical to semantic analysis. Taken together our findings show that the early context effect reflects activation processes in verbal semantic memory.

OBJECTIVE To develop an on-line course in pediatric urology for our urology residents, to expose residents to required pediatric urology content within the confines of an 80-hour work week. METHODS An on-line, Accreditation Council for Graduate Medical Education competency-based course in pediatric urology was designed using a commercially based platform. RESULTS The computer-based teaching course was flexible and provided virtually limitless opportunities for course design, structure, and content. CONCLUSIONS Computer-based teaching platforms may be a useful alternative teaching method to facilitate urology resident education within the confines of an 80-hour work week.

The dipole sound produced by edge scattering of pressure fluctuations at a trailing edge is most often an undesirable effect in turbomachinery and control surface flows. The ability to model the flow mechanisms associated with the production of trailing edge acoustics is important for the quiet design of such devices. The objective of the present research was to experimentally measure flow field and acoustic variables in order to develop an understanding of the mechanisms that generate trailing edge noise. The results of these experiments have provided insight into the causal relationships between the turbulent flow field, unsteady surface pressure, and radiated far field acoustics. Experimental methods used in this paper include particle image velocimetry (PIV), unsteady surface pressures, and far field acoustic pressures. The model investigated had an asymmetric 45° beveled trailing edge. Reynolds numbers based on chord ranged from 1.2 × 10 6 to 1.9 × 10 6 . It was found that the small-scale turbulent motions in the vicinity of the trailing edge were modulated by a large scale von Karman wake instability. The broadband sound produced by these motions was also found to be dependant on the “phase” of the wake instability.

The precise role of the fusiform face area (FFA) in face processing remains controversial. In this study, we investigated to what degree FFA activation reflects additional functions beyond face perception. Seven volunteers underwent rapid event-related functional magnetic resonance imaging while they performed a face-encoding and a face-recognition task. During face encoding, activity in the FFA for individual faces predicted whether the individual face was subsequently remembered or forgotten. However, during face recognition, no difference in FFA activity between consciously remembered and forgotten faces was observed, but the activity of FFA differentiated if a face had been seen previously or not. This demonstrated a dissociation between overt recognition and unconscious discrimination of stimuli, suggesting that physiological processes of face recognition can take place, even if not all of its operations are made available to consciousness.

Objectives To review the world literature for reports of cutaneous metastases from primary genitourinary malignancies and compare them with our experience during a 10-year period. Cutaneous metastases from primary visceral malignancies are uncommon manifestations of advanced disease. Among patients with urologic malignancies, the incidence and appearance of cutaneous metastases are not well established and recognition is poor among practicing urologists. Methods A Medline search and manual bibliographic review was performed to identify peer-reviewed reports pertaining to cutaneous metastases from all visceral malignancies. A comparative review of all pertinent cases arising from primary urologic malignancies was performed. A comprehensive search of our institution's tumor registry was performed to identify all analytic cases of urologic malignancy diagnosed, treated, and followed up between 1990 and 2000. Clinical and pathologic data were collated. Results We identified 2,369 reported cases of cutaneous metastases arising from 81,618 primary solid visceral malignancies, for an overall incidence of 2.9%. Dermatologic spread from primary urologic malignancies of the kidney, bladder, prostate, or testes was noted in 116 (1.3%) of 10,417. The incidence of cutaneous metastases from the kidney, bladder, prostate, and testes was 3.4%, 0.84%, 0.36%, and 0.4%, respectively. Overall, 436 cases of cutaneous metastases from urologic organs were identified in the English-language literature. We identified nine additional cases of pathologically confirmed cutaneous metastatic urologic tumors at our institution in the past 10 years. The most common presentation was an infiltrated plaque or nodules. Most cases displayed clinical features that mimicked common skin disorders. The median disease-specific survival was less than 6 months from the presentation of cutaneous metastasis. Conclusions Cutaneous metastases from urologic tumors are uncommon and occur in 1% of patients with advanced disease. Urologic skin metastases are most common from renal tumors, followed by those of the bladder and then prostate. Their clinical appearance may mimic other common dermatologic disorders affecting patients with advanced malignancies. Definitive diagnosis requires an index of suspicion and skin biopsy. Cutaneous metastases from urologic malignancies are associated with a poor prognosis.

This chapter presents the details for the design, construction, and evaluation of a low-speed, low-turbulence, anechoic wind tunnel facility. This facility allows for the experimental examination of an acoustic field generated by fluid/structure interaction. The chapter begins by describing the motivation for the design of one such facility, located at the University of Notre Dame. This is followed by a detailed description of the design and construction of its major components. Methods for characterization of facility performance are presented and applied to the specific tunnel described. Finally, the contributions of this facility, specifically in the area of a marine propeller’s response to inflow distortions, are summarized.

The recent interest in the development of small UAVs and micro air vehicles has revealed a need for a more thorough understanding of the aerodynamics of small airplanes flying at low speeds. In response to this need, the present work provides a comprehensive study of the lift, drag, and pitching moment characteristics of wings of low aspect ratio operating at low Reynolds numbers. Wind tunnel tests of wings with aspect ratios between 0.5 and 2.0 and with four distinct wing planforms have been conducted at chord-Reynolds numbers in the range of 70,000 to 200,000. In addition, the effect of leading edge shape and fuselage bodies has been studied. As an example of an application of this wind tunnel data, the experimental results are used as part of an aerodynamic analysis procedure. This procedure is incorporated into a genetic algorithm optimization program that generates optimum MAV configurations given certain requirements and constraints. Results obtained by use of this optimization procedure have revealed that useful and accurate design-optimization tools can be developed based on the experimental data presented within this report.

This investigation examined the unsteady response of a stator located downstream of a propeller ingesting broadband turbulence. This response is governed by the turbulent flowfield downstream of the propeller. The analysis of the flowfield is organized in a manner which reflects the causal relationship between influences on the flowfield and the evolution of the flowfield itself. Mathematical models for the contribution of propeller wakes and modification of ingested turbulence are presented and analyzed. Results suggest that this complex flowfield may be fully and accurately represented using simple mathematical models supported by baseline empirical information. Nomenclature

The TRW Low Cost Pintle Engine (LCPE) has significant potential for a dramatic reduction in the cost of launch vehicle propulsion. Using 650,000 Ibf thrust test hardware built for the EELV program, TRW has established a Phase 1 test program under a cooperative agreement with NASA-MSFC. The overall objective of the test program is to demonstrate that a low cost pintle engine can substantially iower the cost of launch vehicles in the U.S. and thus enhance America's competitiveness in the international space transportation market. The 650 klbf LCPE test hardware is presently installed at NASA Stennis Space Center, Test Facility E1. All facility and hardware checkouts tests have been successfully completed, and initial hot fire testing is underway. In this paper, the essential design features of the LCPE are described. Results for the checkout testing and initial hot fire testing are presented, as are plans for continued testing and development of the LCPE. BACKGROUND in the last twenty-five years, only three LO2/LH2 large booster engines have been developed by the free market economy nations. Each of these designs was driven by performance rather than by cost or schedule. Achieving high performance goals requires pushing the limits of technology, resulting in extensive technology and manufacturing development. The resulting engine designs were both complex and extremely costiy to manufacture. Development costs averaged about $2.OB (FY95 $) with engine recurring costs ranging from about $176/lbf thrust for the SSME to $77/lbf thrust for ESAs Vulcain engine. While continuous efforts have been underway in the US to reduce existing engine costs through redesign of key components, these efforts have as yet not resulted in a significant reduction in overall engine cost. For some time, TRW has been advocating a shift to engines lower chamber pressures, simple cycles, low parts count and either pressure fed or pump fed propellent supplies as a way to lower engine production costs by over an order of magnitude (~$5/lbf). TRW began its work with the Low Cost Pintle Engine (LCPE) in the 1960's. The largest of these earlier engines (250,000 Ibf) was pressure-fed tested with earth storabie propellants burning at 300 psia in an ablative lined combustion chamber (DC-93-104). In the 1970's, TRW tested similar engines with LO2/RP-1 and LO2/propane at 2,000 Ibf and 50,000 Ibf with combustion pressures of 300 psia. During the 1990's, with support from McDonnel-Dougias, TRW tested 16,500 Ibf and 40,000 Ibf thrust LO2/LH2 engines'at chamber pressures ranging from 280 psia to 380 psia. These tests demonstrated high performance (>95%) and stable operation. Several stability tests were conducted using 40 grain bombs. No combustion instabilities were detected in these tests or in any of the other tests over a wide range of operating conditions In 1995-1996, a 650,000 Ibf thrust, LOX/LH2 scale-up of these early engines was designed and built during the first phase of the EELV program. This test engine, shown in Figure 1, represents a critical step in the development of the LCPE. its goal is to verify engine performance, combustion stability and ablative life at a full-scale booster size. Under a Cooperative Agreement (CA) with NASA-MSFC, TRW is testing the Thrust Chamber Assembly (TCA) of the LCPE at NASA-SSC. The TCA, consisting of the injector and combustion chamber, will fully demonstrate the capabilities of the pintle injector, ablative thrust chamber and nozzle in a pressure-fed configuration. 1 Copyright ©by TRW Inc. Published by the American Institute of Aeronautics and Astronautics (c)2000 American Institute of Aeronautics & Astronautics or Published with Permission of Author(s) and/or Author(s)' Sponsoring Organization. Figure 1 TRWLCPE 650 klbf Test Engine TEST HARDWARE DESCRIPTION The engine hardware undergoing testing at NASASSC is of heavyweight construction to reduce cost and provide ample margins during the early phases of engine development However, the injector internal flow geometry and basic chamber geometry is identical to that for a future flight engine. Table 1 lists the major operating parameters for the LCPE test engine of this thrust level. The thrust chamber assembly, or TCA (Figure 2), is defined as the injector, headend dome and ablative thrust chamber (consisting of barrel section, throat section and nozzle section). !n the proposed test engines, the barrel section is joined to an integral throat/nozzle section by bolted flange to enable easy refurbishment of the ablative-liners and to enable characterization of performance with varying chamber barrel length.

This paper discusses an experimental investigation of the aeroacoustic response characteristics of a ten-bladed rotor to grid-generated turbulence that was performed at Notre Dame. In order to empirically characterize the rotor response, both the ingested velocity field and resulting far-field sound were measured. The detailed velocity characterization included: a high-resolution mapping of the spatial distribution of the mean velocity and RMS turbulence fluctuations in the rotor plane; an evaluation of the streamwise development of “nearly isotropic” conditions at the rotor inlet plane; and the development of a semi-empirical, functional representation of the 3D wave number spectral density of the ingested turbulence. This turbulence model was used, in conjunction with theoretical speckal analysis techniques, to predict the sound pressure levels in the far-field. These predictions were compared to conesponding measured data to assess the fidelity of the spectral analysis methods and the semi-empirical turbulence model. The measured ten-bladed acoustic response was also compared to the corresponding response of a four-bladcd rotor ingesting the same grid-generated turbulence field, to demonstrate the effect of blade spacing on rotor turbulence ingestion noise.

An experimental investigation of the influence of a leading edge separation region on the unsteady aerodynamic problem for thin, symmetric airfoils exposed to periodic gusting was performed in a subsonic indraft wind tunnel. Two leading edge shapes for the airfoil were used to examine the influence of flow separation both in the unsteady velocity and pressure fields. It is shown that flow separation near the leading edge causes a sharp increase in the unsteady RMS velocity and unsteady surface pressure variation associated with the gust frequency. This also causes a departure from the expectation that the gust information is convected downstream by the freestream in the velocity field. In the absence of such a separation region, velocity and surface pressure results closely resemble inviscid theoretical predictions and expectations. Accurate prediction of unsteady pressure is crucial in estimating the acoustic production of the system.

Studies were done to determine specific differences between adults of Echinostoma revolutum and Echinostoma trivolvis grown singly and concurrently in domestic chicks. Worm recovery at 10-21 days post-infection (p.i.) of E. revolutum and E. trivolvis in singly infected chicks was 21 and 17%, respectively; in concurrent infections, worm recovery for E. revolutum and E. trivolvis was 21 and 16%, respectively. The body area of E. trivolvis was 1.5-2.0 times greater than that of E. revolutum at 10-21 days p.i. Most body organ measurements of the suckers and gonads at 10, 14 and 21 days p.i. were significantly greater in E. trivolvis compared with those of E. revolutum. The mean dry weight/worm at 14 days p.i. was 2.5 mg for E. trivolvis and 1.0 mg for E. revolutum. In single infections, E. revolutum was found only in the rectum and E. trivolvis mainly in the lower ileum, and in concurrent infections worms of both species were found in the rectum. Contrary to a previous report that stated that the body size of adult worms is not a reliable taxonomic indicator between E. revolutum and E. trivolvis, the findings reported here show that body area and organ size can be used to distinguish these closely related species.

A long 778 km high pressure, submarine pipeline supplying natural gas will serve multiple combined cycle gas turbine peaking units on the Pacific Rim. The gas supply flow into the pipeline is constant, but the power plant will primarily operate during daylight hours or in certain situations, operate in a two-shift mode. So the pipeline essentially serves as an increasing pressure, gas storage vessel during the night, and pressure falls off during the day as the gas is fired. Hence, the gas letdown receiving station presented many critical design challenges. Among these were the need for constant plant service pressure control, especially during individual power generator unit startup, shutdown, and upset conditions. In addition, there was a very severe noise attenuation requirement and high gas flow rangeability was required. This complex, integrated gas pressure, control valve letdown system and its operation is described in detail.

Synthesis of the mixed ligand complexes (C5Me5)(C5Me4H)2Ln (Ln = Lu, Y) for comparison with (C5Me5)2(C5Me4H)Ln to evaluate details of steric effects on reductive reactivity has revealed that (C5Me5)3−x(C5Me4H)xLn complexes can reduce dinitrogen to (NN)2−. (C5Me5)(C5Me4H)2Lu reacts with N2 to form [(C5Me5)(C5Me4H)Lu]2(μ-η2:η2-N2), (C5Me5)2(C5Me4H)Y reduces N2 to [(C5Me5)2Y]2(μ-η2:η2-N2), and (C5Me4H)3Sc converts N2 to [(C5Me4H)2Sc]2(μ-η2:η2-N2). Exclusive (C5Me4H)1− loss occurs in each case with formation of (C5Me4H)2 as the byproduct. (C5Me5)2, the signature byproduct of sterically induced reduction reactions, is not observed. Since these complexes do not exhibit unusual steric parameters and since the more crowded (C5Me5)2(C5Me4H)Lu and (C5Me5)3Y do not display analogous reactivity, these reactions do not appear to be sterically induced reductions and suggest a new type of ligand-based reduction pathway involving (C5Me4H)1−.