bluuebunny/crossref_metadata_2025 huggingface dataset:
Survey of transfusion policies at US and Canadian children's hospitals in 2008 and 2009
Authors: Spinella Philip C. , Dressler Alex , Tucci Marisa , Carroll Christopher L. , Rosen Rosa Sanchez , Hume Heather , Sloan Steven R. , Lacroix Jacques ,   for the Pediatric Acute Lung Injury and Sepsis Investigators Network
Published: May 2010

BACKGROUND: Previous surveys have reported variation in transfusion practice or policies in specific pediatric populations. Our objective was to determine the current transfusion policies in US and Canadian children's hospitals for both neonatal and pediatric general populations.

STUDY DESIGN AND METHODS: US and Canadian blood bank (BB) personnel at children's hospitals that provide blood products between the dates of October 2008 and January 2009 were surveyed.

RESULTS: Of the 90 US and Canadian children's hospitals identified, 51 (56.7%) blood bankers or their designees responded. There were 42 of 51 (82.4%) respondents from the United States and 9 of 51 (17.6%) from Canada. There was wide variation in beliefs regarding the effect of red blood cell (RBC) storage age on outcomes with 66.6% of respondents interested in a prospective randomized trial in critically ill children. There was also wide variation in policies restricting the storage age of RBCs according to patient age and clinical condition. In the United States 28 of 33 (84.8%) respondents provide universal leukoreduction of RBCs whereas it is 9 of 9 (100%) in Canada. Variation of policies existed for RBC irradiation and washing. The majority of respondents indicated that RBC transfusions were audited if the pretransfusion hemoglobin level was more than 8 to 10 mg/dL. Fresh whole blood is available at 6 of 40 (15%) responding children's hospitals.

CONCLUSIONS: There is a wide variation in BB policies regarding RBC transfusions at children's hospitals in the United States and Canada. Prospective randomized controlled trials are needed to allow for evidence‐based standards of care regarding RBC transfusions.
Performance characteristics of a novel blood bag in‐line closure device and subsequent product quality assessment
Authors: Serrano Katherine , Levin Elena , Culibrk Brankica , Weiss Sandra , Scammell Ken , Boecker Wolfgang F. , Devine Dana V.
Published: May 2010

BACKGROUND: In high‐volume processing environments, manual breakage of in‐line closures can result in repetitive strain injury (RSI). Furthermore, these closures may be incorrectly opened causing shear‐induced hemolysis. To overcome the variability of in‐line closure use and minimize RSI, Fresenius Kabi developed a new in‐line closure, the CompoFlow, with mechanical openers.

STUDY DESIGN AND METHODS: The consistency of the performance of the CompoFlow closure device was assessed, as was its effect on component quality. A total of 188 RBC units using CompoFlow blood bag systems and 43 using the standard bag systems were produced using the buffy coat manufacturing method. Twenty‐six CompoFlow platelet (PLT) concentrates and 10 control concentrates were prepared from pools of four buffy coats. RBCs were assessed on Days 1, 21, and 42 for cellular variables and hemolysis. PLTs were assessed on Days 1, 3, and 7 for morphology, CD62P expression, glucose, lactate, and pH. A total of 308 closures were excised after processing and the apertures were measured using digital image analysis.

RESULTS: The use of the CompoFlow device significantly improved the mean extraction time with 0.46 ± 0.11 sec/mL for the CompoFlow units and 0.52 ± 0.13 sec/mL for the control units. The CompoFlow closures showed a highly reproducible aperture after opening (coefficient of variation, 15%) and the device always remained opened. PLT and RBC products showed acceptable storage variables with no differences between CompoFlow and control.

CONCLUSIONS: The CompoFlow closure devices improved the level of process control and processing time of blood component production with no negative effects on product quality.
A clinical prediction tool to estimate the number of units of red blood cells needed in primary elective coronary artery bypass surgery
Authors: Welsby Ian , Crow Jennifer , Bandarenko Nicholas , Lappas George , Phillips‐Bute Barbara , Stafford‐Smith Mark
Published: May 2010

BACKGROUND: Red blood cell (RBC) transfusion is common during cardiac surgical procedures. Empiric crossmatching, without attempting to estimate individual transfusion requirements is typical. We hypothesized that a clinical prediction tool could be developed to estimate the number of units of RBCs needed for coronary artery bypass grafting (CABG) surgery.

STUDY DESIGN AND METHODS: With institutional review board approval, detailed demographic, risk factor, and transfusion data of primary elective CABG procedures (n = 5887) from September 1, 1993, to June 20, 2002, were studied and the data set was divided into development and validation subgroups. Multivariable ordinal logistic regression was used to develop and validate transfusion risk factors, assign them a relative weight, and create a model to stratify patients into groups depending on predicted need for 0, 2, 4, or more than 4 RBC units. The model was compared with current standard practice of crossmatching 4 RBC units in terms of observed blood product usage over the study period.

RESULTS: Demographic and transfusion risk factor variables in the development (n = 3876) and validation (n = 2011) data sets were similar. The predictive value of the model was good for the development and validation groups, with a c‐index of 0.79 and 0.78, respectively. Applying the predictive model reduced the number of crossmatches by 30% without underproviding RBC units and increased the percentage of patients crossmatched exactly for the required number of units from 11% to 21%.

CONCLUSIONS: Predictive factors for RBC transfusion were identified and used to construct a clinical tool to conserve blood bank resources without increasing patient risk.
Demographic changes and predicting blood supply and demand in the Netherlands
Authors: Borkent‐Raven Barbara A. , Janssen Mart P. , Van Der Poel Cees L.
Published: May 2010

BACKGROUND: Concerns have been raised that aging of the general population will increase the demand for blood products. Modeling can be applied to assess trends in blood demand and supply and predict how these will develop over time.

STUDY DESIGN AND METHODS: We developed mathematical models to describe and predict the national demand of red blood cell (RBC) products. The first demand model assumes that the mean numbers of transfusions per inhabitant per age and sex are constant. A second demand model incorporates observed changes in clinical blood use over time. Further, a donation model is developed to predict future RBC supply. To estimate the supply of whole blood donations, we used annual donor retention rates, donor recruitment rates, and mean numbers of donations per donor year.

RESULTS: The model based on demography only predicts an increase of 23% in RBC demand over 2008 to 2015. The second model, incorporating both demographic changes and trends in clinical RBC use, predicts a decrease of RBC demand by 8% over the same period. The predicted RBC supply closely follows the demand as predicted by the second model.

CONCLUSIONS: Despite an aging population, RBC demand may not increase as much as predicted in other studies. This depends on the extent to which other effects, like that of optimal blood use, will neutralize the effects of aging of the transfusion recipient population. Still, the observed downward trend in donor recruitment in the Netherlands must be stopped to maintain a sufficient RBC supply.
Effect of Process Variables on the Microstructure of Hollow Hydroxyapatite Microspheres Prepared by a Glass Conversion Method
Authors: Fu Hailuo , Rahaman Mohamed N. , Day Delbert E.
Published: May 2010

Solid microspheres (diameter=106–150 μm) of a Li2O–CaO–B2O3 glass were reacted in a K2HPO4 solution to form hollow hydroxyapatite (HA) microspheres. The effect of the temperature (25°–60°C), K2HPO4 concentration (0.01–0.25M), and pH (9–12) of the solution on the diameter (d) of the hollow core normalized to the diameter (D) of the HA microspheres, the surface area, and the pore size of the microsphere wall was studied. The statistically significant process variables that influenced these microstructural characteristics were evaluated using a factorial design approach. While the pH had little effect, the concentration of the solution had a marked effect on d/D, surface area, and pore size, whereas temperature markedly influenced d/D and pore size, but not the surface area. The largest hollow core size (d/D value ≈0.6) was obtained at the lowest temperature (25°C) or the lowest K2HPO4 concentration (0.02M), while microspheres with the highest surface area (140 m2/g), with pores of size 10−12 nm were obtained at the highest concentration (0.25M). The consequences of these results for potential application of these hollow HA microspheres as devices for local delivery of proteins, such as drugs or growth factors, are discussed.
Synthesis and Properties of Homogeneous Nb‐Doped Bismuth Oxide
Authors: Weng Ching‐Hung , Wei Wen‐Cheng J.
Published: May 2010

Nb2O5and Bi2O3powders were dispersed by anionic dispersants separately and followed by optimized colloidal processing steps to obtain the best mixing results. The influences of the dispersants were investigated by the measurements of zeta‐potential, dissolution of cations, adsorption of the dispersant, and size distribution of the suspensions. The homogeneity of sintered samples was checked by quantitative EDS and analyzed by Student's (t)‐statistics. Detailed analyses on surface properties of powder to microstructure and electric conductivity are reported. The best 21 mol% Nb‐doped Bi2O3(B21N) has the conductivity improvement 1.0–5.3 times better than comparable cases in the temperature range of 450°–700°C.
Influence of Particle Size on Ice Nucleation and Growth During the Ice‐Templating Process
Authors: Deville Sylvain , Maire Eric , Lasalle Audrey , Bogner Agnes , Gauthier Catherine , Leloup Jérôme , Guizard Christian
Published: May 2010

The solidification behavior of suspensions of alumina particles during directional solidification is investigated here byin situobservations using X‐ray radiography and tomography. The objective of this study was to assess the influence of particle size on the solidification behavior of the suspensions during the early stages of solidification. Four powders with particle size in the range of 0.2–3.4 μm (median size) were investigated. Solidification is obtained by cooling at a constant rate, starting from room temperature. Attention is specifically paid to the nucleation and growth behavior of the ice crystals in these suspensions. We propose that the nucleation of ice crystals is controlled by the particle size, the surface of the particles acting as nucleation sites. Smaller particle size leads to a lower degree of supercooling because nucleation and growth can proceed at a higher temperature than with larger particles. The initial interface velocity is dependent on the degree of supercooling, and controls the extent of the initial structural gradient in the resulting porous materials.
Analysis of High‐Voltage ZnO Varistor Prepared from a Novel Chemically Aided Method
Authors: Cheng Lihong , Li Guorong , Zheng Liaoying , Zeng Jiangtao , Gu Yan , Zhang Fuping
Published: May 2010

High‐voltage varistor materials were prepared using an ultrafine additives precursor obtained from the precipitation method. Microstructural and electrical studies showed that the sample exhibited a smaller average grain size (d=4.5 μm) and a considerably higher breakdown voltage (Eb=1610±30 V/mm) as compared with the conventional one (d=6.5 μm, Eb=400±30 V/mm). The high voltage is attributed to the improvement in microstructure homogeneity and the formation of more active grain boundaries per unit volume. This novel route may explore the commercial possibility of device miniaturization.
Well‐differentiated neuroendocrine carcinoma (malignant carcinoid) of the extrahepatic biliary tract: report of two cases and literature review
Authors: SQUILLACI SALVATORE , MARCHIONE ROBERTA , PICCOLOMINI MANUELA , COLOMBO FABIO , BUCCI FRANCESCO , BRUNO MARIANTONIETTA , BISCEGLIA MICHELE
Published: May 2010

Squillaci S, Marchione R, Piccolomini M, Colombo F, Bucci F, Bruno M, Bisceglia M. Well‐differentiated neuroendocrine carcinoma (malignant carcinoid) of the extrahepatic biliary tract: report of two cases and literature review. APMIS 2010; 118: 543–56.

The objectives of this study were to evaluate the frequency of carcinoid tumors of the extrahepatic biliary ducts (EHBDs) and the pathologic progression and the role of surgery in the management of this disease. We describe two cases of malignant carcinoids of the EHBDs, which presented as common bile duct tumors in two adult male patients, aged 52 and 70 years, who were diagnosed histologically on surgical resection specimens. A comprehensive review of the literature has also been performed with a focus on survival data. Microscopically, the tumors presented herein were composed of relatively small rounded cells with a trabecular or nesting pattern. Both cases were diffusely immunopositive for chromogranin and synaptophysin, and one of them was also focally reactive with somatostatin and pancreatic polypeptide. There was no expression in any of these tumors of thyroid transcription factor‐1 (TTF‐1), gastrin, insulin, glucagon, vasoactive intestinal peptide (VIP) and prolactin. The tumor showed transmural invasion in both cases, with lymph node metastasis and subcapsular liver tissue infiltration in one. Both patients are alive with no evidence of disease 41 months and 59 months, respectively, after surgery. Despite being extremely uncommon, with only 70 cases reported to date, carcinoids should be included in the differential diagnosis of EHBD tumors. This study emphasizes the necessity of complete surgical resection as the gold standard treatment for these lesions, and the importance of a correct pathologic diagnosis for prognostic implications.
Congenital chylothorax: from foetal life to adolescence
Authors: Caserío S , Gallego C , Martin P , Moral MT , Pallás CR , Galindo A
Published: May 2010

Aim:  To analyse the main prenatal and postnatal features of congenital chylothorax (CC), and the outcome including mid‐term follow‐up.

Methods:  We searched our databases for CC diagnosed between 1990 and 2006. Data of 29 cases were retrieved and analysed. Follow‐up until 3 years of age was available for all patients.

Results:  Most patients were diagnosed prenatally (94%) and most cases were complicated by foetal hydrops (66.7%). The overall survival rate at 3 years was 56%. A significantly poorer outcome was observed when foetal hydrops, preterm birth < 34 weeks, large effusions and/or early‐onset pneumothorax were present. An important but not significant improvement in the survival rate was observed through the study period; while in 1990–1998, the survival rate was 41.7%, from 1999 to 2006 it was 66.7% (p = 0.19). In the mid‐term follow‐up, we did not observe any recurrence of CC and most infants remain asymptomatic. However, 27% of survivors were diagnosed as having asthma in early infancy.

Conclusion:  CC still carries a significant risk of perinatal mortality. However, continuous advances in foetal and neonatal medicine are improving the prognosis of these patients, and nowadays most of them are likely to survive. Beyond the neonatal period, most survivors have an uneventful outcome.
Care of chronic wounds in palliative care and end‐of‐life patients
Authors: Chrisman Christine A
Published: May 2010

The aim of this paper was to provide a literature synthesis on current wound care practices for the management of chronic wounds in palliative care and end‐of‐life patients, focusing on the control of wound‐related symptoms for comfort and improved quality of life. These wounds included pressure ulcers, venous and arterial leg ulcers, diabetic ulcers and fungating malignant wounds. Wound‐related symptoms included pain, exudate, malodour, infection, bleeding, dressing comfort and negative psychological and social functioning. Best care wound practices were formulated for each wound type to ease suffering based on the literature review. Although symptom management strategies for comfort may work in tandem with healing interventions, it is important to recognise when efforts towards wound closure may become unrealistic or burdensome for the patient at end of life. Thus, unique aspects of palliative wound care feature clinical indicators for early recognition of delayed healing, quality of life measurement tools related to chronic wounds, and comfort care strategies that align with patient wishes and realistic expectations for wound improvement.
A prospective, randomized trial of silver containing hydrofiber dressing versus 1% silver sulfadiazine for the treatment of partial thickness burns
Authors: Muangman Pornprom , Pundee Chanin , Opasanon Supaporn , Muangman Saipin
Published: May 2010

Silver sulfadiazine has been used as a topical burn wound treatment for many years. Pain associated with dressing changes is a common problem in burn wounds. Aquacel Ag, a hydrofiber dressing coated with ionic silver has been reported to reduce burn wound infection and promote antimicrobial activity. The purpose of this study was to show the benefits of Aquacel Ag for the treatment of partial thickness burns. This prospective randomized study was conducted in 70 patients who had partial thickness burns less than 15% of total body surface area and were treated at Siriraj outpatient burn clinic during December 2006–February 2008. Patients were divided into two groups: Aquacel Ag‐treated group with dressing changes every 3 days (35 patients) and 1% silver sulfadiazine‐treated group, with daily dressing changes (35 patients). There was no difference in demographic data including age, gender, burn percentage between groups. Time‐to‐wound healing pain score during dressing change and cost of treatment were compared between both groups. Time‐to‐wound closure was significantly shorter in the Aquacel Ag‐treated group (10 ± 3 versus 13.7 ± 4 days, P < 0·02) as well as pain scores at days 1, 3 and 7 (4·1 ± 2·1, 2·1 ± 1·8, 0·9 ± 1·4 versus 6·1 ± 2·3, 5·2 ± 2·1, 3·3 ± 1·9, respectively, P < 0·02). Total cost of treatment was 52 ± 29 US dollars for the Aquacel Ag‐treated group versus 93 ± 36 US dollars for the silver sulfadiazine‐treated group. This study showed that Aquacel Ag increased time to healing, decreased pain symptoms and increased patient convenience because of limiting the frequency of replacement of the dressing at lower total cost. This study confirms the efficacy of Aquacel Ag for the treatment of partial thickness burns at an outpatient clinic.
The Swift-BAT hard X-ray sky monitoring unveils the orbital period
of the HMXB IGR J16493-4348
Authors: Cusumano G. , La Parola V. , Romano P. , Segreto A. , Vercellone S. , Chincarini G.
Published: May 2010

IGR J16493−4348 is a supergiant high-mass X-ray binary discovered by INTEGRAL in 2004. The source is detected at a significance level of ∼21 standard deviations in the Swift Burst Alert Telescope survey data collected during the first 54 months of the Swift mission. The timing analysis reveals an orbital period of ∼6.78 d and the presence of a full eclipse of the compact object. The dynamical range (variability up to a factor of ∼20) observed during the BAT monitoring suggests that IGR J16493−4348 is a wind-fed system. The derived semimajor axis of the binary system is ∼55 R⊙ with an orbit eccentricity lower than 0.15.
Intraoperative mitomycin C versus autologous conjunctival autograft in surgery of primary pterygium with four‐year follow‐up
Authors: Koranyi Gabor , Artzén Ditte , Seregard Stefan , Kopp Eva Dafgard
Published: May 2010

Purpose:  To compare the 4‐year outcome of primary pterygium excision using intraoperative mitomycin C (MMC) with suturing a free conjunctival autograft (CA).

Methods:  A total of 115 eyes with nasal primary pterygium of 115 patients were included in the study. After randomization into two groups, the eyes were operated on by a single surgeon (GK). After excision of the pterygium, 56 eyes received 0.04% MMC intraoperatively on the bare sclera for 3 min and 59 eyes received a free CA sutured using 7‐0 Vicryl. Postoperative follow‐up was 4 years. Main outcome measures were recurrences, re‐operations, surgery time, complications, visual acuity and astigmatism. Statistical evaluation was performed with the chi‐squared test.

Results:  The recurrence rate was 38% in the MMC group and 15% in the CA group (p < 0.05). The re‐operation rate of the recurrences was 53% in the MMC group and 29% in the CA group. Average surgery time was 13 minutes (range: 6–22 min) in the MMC group and 26 min (range: 18–32 min) in the CA group (p < 0.01). There was no significant change in best‐corrected visual acuity and astigmatism. One major complication occurred in each group. The most frequently observed complication was delayed epithelial healing (40%) and mild scleral thinning (20%) in the MMC group and suture‐related inflammation in the CA group (10%).

Conclusion:  Pterygium surgery including free autologous conjunctival grafting is associated with fewer recurrences, re‐operations and complications than using the bare sclera technique together with single‐dose intraoperative MMC.
Rotordynamic Analysis of a Large Industrial Turbocompressor Including Finite Element Substructure Modeling
Authors: Moore J. Jeffrey , Vannini Giuseppe , Camatti Massimo , Bianchi Paolo
Published: May 2010

A rotordynamic analysis of a large turbocompressor that models both the casing and supports along with the rotor-bearing system was performed. A 3D finite element model of the casing captures the intricate details of the casing and support structure. Two approaches are presented, including development of transfer functions of the casing and foundation, as well as a fully coupled rotor-casing-foundation model. The effect of bearing support compliance is captured, as well as the influence of casing modes on the rotor response. The first approach generates frequency response functions (FRFs) from the finite element case model at the bearing support locations. A high-order polynomial in numerator-denominator transfer function format is generated from a curve fit of the FRF. These transfer functions are then incorporated into the rotordynamics model. The second approach is a fully coupled rotor and casing model that is solved together. An unbalance response calculation is performed in both cases to predict the resulting rotor critical speeds and response of the casing modes. The effect of the compressor case and supports caused the second critical speed to drop to a value close to the operating speed and not compliant with the requirements of the American Petroleum Institute (API) specification 617 7th edition. A combination of rotor, journal bearing, casing, and support modifications resulted in a satisfactory and API compliant solution. The results of the fully coupled model validated the transfer function approach.
Nanotechnology Coatings for Erosion Protection of Turbine Components
Authors: Swaminathan V. P.“Swami” , Wei Ronghua , Gandy David W.
Published: May 2010

Solid particle erosion (SPE) and liquid droplet erosion (LDE) cause severe damage to turbine components and lead to premature failures, business loss, and repair costs to power plant owners and operators. Under a program funded by the Electric Power Research Institute, TurboMet International and Southwest Research Institute (SRI) have developed hard erosion resistant nanocoatings and have conducted evaluation tests. These coatings are targeted for application in steam and gas turbines to mitigate the adverse effects of SPE and LDE on rotating blades and stationary vanes. Based on a thorough study of the available information, the most promising coatings, such as nanostructured titanium silicon carbonitride (TiSiCN), titanium nitride (TiN), and multilayered nanocoatings, were selected. State-of-the-art nanotechnology coating facilities at SwRI were used to develop the coatings. The plasma enhanced magnetron sputtering method was used to apply these coatings on various substrates. Ti–6Al–4V, 12Cr, 17-4PH, and custom 450 stainless steel substrates were selected based on the current alloys used in gas turbine compressors and steam turbine blades and vanes. Coatings with up to 30μm thickness have been deposited on small test coupons. Initial screening tests on coated coupons by solid particle erosion testing indicate that these coatings have excellent erosion resistance by a factor of 20 over the bare substrate. Properties of the coating, such as modulus, hardness, microstructural conditions including the interface, and bond strength, were determined. Tensile and high-cycle fatigue tests on coated and uncoated specimens indicate that the presence of the coatings has no negative effects but has a positive influence on the high-cycle fatigue strength at zero and high mean stresses.
Centrifugal Compressor Stability Prediction Using a New Physics Based Approach
Authors: Moore J. Jeffrey , Ransom David L.
Published: May 2010

The accurate prediction of centrifugal compressor stability continues to be an important area of interest in the oil and gas industries. Ensuring stability is critical to the cost-effective installation and operation of these machines in remote environments, where field stability problems are much more expensive to diagnose and correct. Current industry standards and tools for the prediction of impeller destabilizing forces are based on empirical methods that, to date, have served fairly well for systems with reasonable stability margins. However, as stability margins are decreased, use of a modeling method that is more physics based and can better represent the observed trends in machine behavior at low stability margins is required. Furthermore, the development of megaclass liquefied natural gas (LNG) compressors and ultra-high pressure re-injection compressors provides further motivation to improve accuracy. In this paper, a new physics based expression for the prediction of impeller cross-coupling, previously described by Moore et al. (“Rotordynamic Force Prediction of Centrifugal Compressor Impellers Using Computational Fluid Dynamics,” ASME Paper No. GT2007-28181), is further investigated by analyzing several classes and scale factors of impellers ranging from 2D designs used in re-injection to full 3D impellers typically used in LNG. The new expression is based on both computational fluid dynamics simulation and experimental test data from a known instability. These results are then applied to two case studies of marginally stable and unstable compressors in the field that were studied by the authors’ company. For each case study, the system stability is evaluated using both the new physics based expression as well as the more traditional empirical approaches. Comparisons are made for overall stability prediction as well as sensitivity to system changes. Conclusions are made regarding the applicability and limits of this new approach.
High Strength, Ductile Braze Repairs for Stationary Gas Turbine Components—Part II
Authors: Miglietti Warren , Du Toit Madeleine
Published: May 2010

Both aviation and land based turbine components such as vanes/nozzles, combustion chambers, liners, and transition pieces often degrade and crack in service. Rather than replacing with new components, innovative repairs can help reduce overhaul and maintenance costs. These components are cast from either Co-based solid solution superalloys such as FSX-414, or Ni-based gamma prime precipitation strengthened superalloys such as IN738. The nominal compositions of FSX-414 and IN738 are Co–29.5Cr–10.5Ni–7W–2Fe (max)–0.25C–0.012B and Ni–0.001B–0.17C–8.5Co–16Cr–1.7Mo–3.4Al–2.6W–1.7Ta–2Nb–3.4Ti–0.1Zr, respectively. Diffusion brazing has been used for over 4 decades to repair cracks and degradation on these types of components. Typically, braze materials utilized for component repairs are Ni and Co-based braze fillers containing B and/or Si as melting point depressants. Especially when repairing wide cracks typically found on industrial gas turbine components, these melting point depressants can form brittle intermetallic boride and silicide phases that effect mechanical properties such as low cycle and thermal fatigue. The objective of this work is to investigate and evaluate the use of hypereutectic Ni–Cr–Hf and Ni–Cr–Zr braze filler metals, where the melting point depressant is no longer B, but Hf and/or Zr. Typically, with joint gaps or crack widths less than 0.15 mm, the braze filler metal alone can be utilized. For cracks greater than 0.15 mm, a superalloy powder is mixed with the braze filler metal to enable wide cracks to be successfully braze repaired. As a means of qualifying the diffusion braze repair, both metallurgical and mechanical property evaluations were carried out. The metallurgical evaluation consisted of optical and scanning electron microscopy, and microprobe analysis. The diffusion brazed area consisted of a fine-grained equiaxed structure, with carbide phases, γ (gamma) dendrites, flower shaped/rosette γ-γ′ (gamma-gamma prime) eutectic phases and Ni7Hf2, Ni5HF, or Ni5Zr intermetallic phases dispersed both intergranularly and intragranularly. Hardness tests showed that the Ni–Hf and Ni–Zr intermetallic phase only has a hardness range of 250–400 Hv; whereas, the typical Cr-boride phases have hardness ranges from 800 Hv to 1000 Hv. Therefore, the hardness values of the Ni–Hf and Ni–Zr intermetallic phases are 2.5–3.2 times softer than the Cr-boride intermetallic phases. As a result, the low cycle fatigue (LCF) properties of the wide gap Ni–Cr–Hf and Ni–Cr–Zr brazed joints are superior to those of the Ni–Cr–B braze filler metals. The mechanical property evaluations were tensile tests at both room temperature and elevated temperature, stress rupture tests from 760°C to 1093°C and finally LCF, the latter being one of the most important and severe tests to conduct, since the cracks being repaired are thermal fatigue driven. At the optimum braze thermal cycle, the mechanical test results achieved were a minimum of 80% and sometimes equivalent to that of the base metals properties.
Computational Prediction of the Effect of Microcavitation on an Atomization Mechanism in a Gasoline Injector Nozzle
Authors: Ishimoto Jun , Sato Fuminori , Sato Gaku
Published: May 2010

The effect of microcavitation on the 3D structure of the liquid atomization process in a gasoline injector nozzle was numerically investigated and visualized by a new integrated computational fluid dynamics (CFD) technique for application in the automobile industry. The present CFD analysis focused on the primary breakup phenomenon of liquid atomization which is closely related to microcavitation, the consecutive formation of liquid film, and the generation of droplets by a lateral flow in the outlet section of the nozzle. Governing equations for a high-speed lateral atomizing injector nozzle flow taking into account the microcavitation generation based on the barotropic large eddy simulation-volume of fluid model in conjunction with the continuum surface force model were developed, and then an integrated parallel computation was performed to clarify the detailed atomization process coincident with the microcavitation of a high-speed nozzle flow. Furthermore, data on such factors as the volume fraction of microcavities, atomization length, liquid core shapes, droplet-size distribution, spray angle, and droplet velocity profiles, which are difficult to confirm by experiment, were acquired. According to the present analysis, the atomization rate and the droplets-gas atomizing flow characteristics were found to be controlled by the generation of microcavitation coincident with the primary breakup caused by the turbulence perturbation upstream of the injector nozzle, hydrodynamic instabilities at the gas-liquid interface, and shear stresses between the liquid core and periphery of the jet. Furthermore, it was found that the energy of vorticity close to the gas-liquid interface was converted to energy for microcavity generation or droplet atomization.
Multiharmonic Forced Response Analysis of a Turbine Blading Coupled by Nonlinear Contact Forces
Authors: Siewert Christian , Panning Lars , Wallaschek Jörg , Richter Christoph
Published: May 2010

In turbomachinery applications, the rotating turbine blades are subjected to high static and dynamic loads. The static loads are due to centrifugal stresses and thermal strains whereas the dynamic loads are caused by the fluctuating gas forces resulting in high vibration amplitudes, which can lead to high cycle fatigue failures. Hence, one of the main tasks in the design of turbomachinery blading is the reduction in the blade vibration amplitudes to avoid high dynamic stresses. Thus, coupling devices like underplatform dampers and tip shrouds are applied to the blading to reduce the vibration amplitudes and, therefore, the dynamic stresses by introducing nonlinear contact forces to the system. In order to predict the resulting vibration amplitudes, a reduced order model of a shrouded turbine blading is presented including a contact model to determine the nonlinear contact forces. To compute the forced response, the resulting nonlinear equations of motion are solved in the frequency domain using the multiharmonic balance method because of the high computational efficiency of this approach. The transformation from the time domain into the frequency domain is done by applying Galerkin’s method in combination with a multiharmonic approximation function for the unknown vibration response. This results in an algebraic system of nonlinear equations in the frequency domain, which has to be solved iteratively in order to compute the vibration response. The presented methodology is applied to the calculation of the forced response of a nonlinear coupled turbine blading in the frequency domain.
Quantification of the Long-Term Performance of Steels T91 and 316L in Oxygen-Containing Flowing Lead-Bismuth Eutectic at 550°C
Authors: Schroer Carsten , Konys Juergen
Published: May 2010

The long-term performance of ferritic/martensitic steel T91 and austenitic 316L in oxygen-containing flowing lead-bismuth eutectic at 550°C was investigated by exposing the materials for up to 15,000 h in the CORRIDA loop. The velocity of the liquid-metal flow was 2 m/s and the concentration of dissolved oxygen averaged 1.6×10−6 mass %. The resulting corrosion processes and products were analyzed and quantified using metallographic methods.
Control of Membrane Protein Topology by a Single C-Terminal Residue
Authors: Seppälä Susanna , Slusky Joanna S. , Lloris-Garcerá Pilar , Rapp Mikaela , von Heijne Gunnar
Published: May 2010

In, Out, Positive Charge About

The mechanism by which multispanning, helix-bundle membrane proteins are inserted into their target membrane is not completely understood. EmrE is an
Escherichia coli
inner-membrane protein with four transmembrane helices that can take up two distinct topologies—with its amino terminus toward the cytosol, or away from the cytosol.

Seppälä
et al.

(p.
1698
, published online 27 May; see the Perspective by

Tate

) exploited the dual-topology property of EmrE to study the mechanism of membrane protein assembly in
Escherichia coli
. Systematically exploring the effects of positively charged residues on the topology of EmrE revealed that the membrane orientation of EmrE constructs with four or five transmembrane helices could be controlled by a single positively charged residue placed in different locations throughout the protein, including the very carboxyl terminus. Such global control of membrane protein topology raises important questions concerning how multispanning membrane proteins are handled by the membrane protein insertion machinery.
Explaining the Structure of the Archean Mass-Independent Sulfur Isotope Record
Authors: Halevy Itay , Johnston David T. , Schrag Daniel P.
Published: May 2010

Modeling suggests that volcanic output and microorganisms created a distinctive profile of sulfur isotopes on early Earth.
U – Pb age constraints for the lithotectonic evolution of the Grenville Province along the Mauricie transect, Quebec
Authors: Corrigan David , Breemen Otto van
Published: May 2010

New U–Pb zircon and monazite ages on 12 samples from the Mauricie transect in Quebec provide constraints on the lithologic and tectonic evolution of the south-central Grenville Province. From lowest to highest structural levels, the Mékinac, Shawinigan, and Portneuf – St. Maurice domains are identified on the basis of protolith age, tectonic overprint, and plutonism. The structurally highest Portneuf – St. Maurice domain consists of remnants of an island arc (Montauban Group) that was deformed and metamorphosed before and during the intrusion of continental arc plutons (La Bostonnais complex). A tonalitic orthogneiss yielding a [Formula: see text] zircon age suggests that most of the structurally underlying Mékinac and Shawinigan domains consist of orthogneisses that may be high-grade equivalents of the La Bostonnais complex. A voluminous metasedimentary unit occurring in the Shawinigan domain (St. Boniface unit) was deposited between ca. 1.18 and 1.09 Ga, precluding any correlation with the ca. 1.45 Ga Montauban Group. Two suites of anorthosite–mangerite–charnockite–granite (AMCG) plutonic rocks are identified on the basis of field relationships and isotopic age. A megacrystic granite belonging to the "older" AMCG suite yielded a [Formula: see text] zircon age. Three plutons from the "younger" suite yielded ages of [Formula: see text], 1059 ± 2, and 1056 ± 2 Ma. The Mékinac and Shawinigan domains, excluding the younger AMCG plutons, were penetratively deformed at granulite to uppermost amphibolite facies during west-northwest-directed thrusting between 1.15 and 1.09 Ga. At ca. 1.09 Ga, a transition from contraction to oblique extension resulted in the juxtaposition of the "cold" Portneuf – St. Maurice domain with the "hot" Shawinigan domain, along the Tawachiche shear zone. Oblique extension may have been active from ca. 1.09 to 1.04 Ga and was contemporaneous with emplacement of the younger AMCG suite.
Archean plate tectonics: what can be learned from continental geology?
Authors: Sleep Norman H.
Published: May 2010

Some basic questions about Archean plate tectonics can be addressed by examining accretionary Archean margins, in particular fault zones with significant strike-slip components on the Canadian Shield. (1) Were the oceanic plates typically rigid like modern plates? Yes. Significant lateral viscosity contrasts in the lithosphere between plates and plate boundaries are required for major strike-slip faults to exist. Conversely, strike-slip faults are a kinematic consequence of rigid plates. (2) Did large oceanic plates exist in the Archean? Probably. First, the length and offset of the longest preserved segments of Archean faults are similar to modern examples such as in Alaska. Less directly, the duration of a period with a consistent sense of strike slip at a point on the continental side of an accretionary margin should be related to the time that a typical oceanic plate remains outboard of the margin. This time varies proportionally with size of typical ocean plates and inversely with their velocity. The duration of an example of persistent strike slip on the Canadian Shield is comparable to that of Cenozoic examples. (3) Did old oceanic crust and hence moderate plate velocities occur in the Archean? Perhaps. Paleomagnetic poles are the most direct line of evidence, but they usually relate to continental blocks. The duration of consistent strike-slip motion, preserved alkalic seamounts which record eruption on old oceanic crust, and the duration of ocean basins are potential indirect indications. Overall, the hotter mantle does not appear to have had a great effect on Archean plate motions. Thus, the geometry and rate of plate tectonics are strongly influenced by the lithosphere.
The Slave Province: a distinct Archean craton
Authors: Padgham W. A. , Fyson W. K.
Published: May 2010

The Slave Province is a relatively small Late Archean craton that exhibits distinctive rock associations and structures. By comparison with the much larger Superior Province, differences are evident in (i) the abundance of sedimentary versus volcanic rocks and of felsic versus mafic volcanic rocks; (ii) the greater evidence for sialic basement; (iii) the higher proportion of more evolved potassium-rich granite; (iv) the type, setting, and timing of gold and base-metal mineralization; and (v) a regional zonation of gold deposits that seems to be a unique feature of the Slave Province. Contrasts in structure are also significant: the large-scale linear belts and boundaries (sutures?) that characterize the Superior Province have no obvious counterpart in the Slave Province. Despite some similarities with other Archean cratons, the distinct features of the Slave Province are important, for they imply that no single Archean craton should be used to develop a universal paradigm for the genesis and tectonic evolution of Archean crust.
Deformation across the western Quetico subprovince and adjacent boundarl regions in Minnesota
Authors: Bauer Robert L. , Hudleston Peter J. , Southwick David L.
Published: May 2010

North- to northwest-directed crustal shortening across the western Quetico subprovince and its boundary regions produced a complex deformation sequence within the Quetico belt and resulted in concentrated zones of dextral ductile shear in the boundary regions within the adjacent greenstone–granite terranes. In this paper, we review and introduce new data on the regional deformation features and their geometries and discuss the history of generation of these features. We attribute the deformation sequence to differential partitioning of shortening and shear strains during dextral transpression associated with oblique convergence and accretion along the southern margin of the Superior Province.The turbiditic wacke in the western Quetico subprovince, now typically amphibolite-facies schist and migmatite, underwent an early deformation stage that included recumbent folding (F1) and the generation of an S1 bedding-parallel foliation. This event is most evident along the northern and southern boundaries of the subprovince, but it is also recognized in the lower grade metasedimentary rocks in the adjacent Wawa and Wabigoon subprovinces. In these subprovinces, F1 folding may have been associated with higher level thrusting and allochthonous emplacement of greenstone units. Despite our F1 designation of this event, it it unlikely that this deformation was synchronous across the subprovinces.Widespread upright folding of the overturned limbs of F1 folds produced moderately to gently plunging F2 folds with east–west-trending axial planes. F, folds, with an associated L, stretching lineation subparallel to fold hinges, are well developed along the southern and northern margins of the Quetico subprovince and in the metasediments of the adjacent Wawa subprovince. During this event, ductile dextral shear was concentrated in steeply dipping east–west-trending shear zones in the Wawa subprovince and in the region of the Rainy Lake – Seine River fault along the Quetico–Wabigoon subprovince boundary. In the northern Wawa subprovince, shear was strongly concentrated in relatively incompetent, steeply dipping metasedimentary and tuffaceous units interlayered with more competent greenstone units. Concentrated zones of ductile shear are not evident within the Quetico subprovince away from its boundary regions. However, emplacement of syntectonic plutons in the central Quetico reoriented F2 folds which were then refolded by large regional F3 folds during continued regional shortening.
Geodynamic evolution of the southern Abitibi and Pontiac terranes: evidence from geochemistry of granitoid magma series (2700–2630 Ma)
Authors: Feng Rui , Kerrich Rob
Published: May 2010

Four distinct granitic series developed during the evolution of the Archean Abitibi Southern Volcanic Zone (SVZ): (1) A minor synvolcanic tonalite–trondhjemite–granodiorite (TTG) series was emplaced at ~2700 Ma, which has extremely low K2O (<1.5 wt.%), Rb (<50 ppm), and Sr (<200 ppm), higher Nb, Y, and Sc, flat rare-earth-element (REE) patterns, and negative Eu anomalies. (2) A voluminous tonalite – granodiorite – granite – quartz monzonite (TGGM) series developed syntectonically at ~2695–2685 Ma, and displays low K2O (1–3 wt.%), Rb (10–50 ppm), Ba (<1000 ppm), and U, enhanced Sr, depletion of Ta, Nb, and Ti, and strongly fractionated REE patterns (La/Ybn = 49–21). (3) A late-tectonic quartz syenite – quartz monzonite – granite (SMG) series was emplaced from ~2685 to 2675 Ma, and is grossly similar to the TGGM but has lower CaO/(K2O + Na2O) and greater concentrations of Rb, Ba, Th, and U. (4) A late-tectonic to posttectonic alkali feldspar syenite – alkali feldspar quartz syenite (SS) series was emplaced from 2680 to 2670 Ma, and occurs along regional strike-slip structures. The primitive rocks (SiO2 ≤ 65 wt.%) exhibit coenrichment of large-ion lithophile elements (LILE) and mafic elements (Cr, Co, and Ni) and strongly fractionated REE patterns, whereas evolved phases (SiO2 ≥ 65 wt.%) display lower contents of compatible and incompatible elements stemming from differentiation.In the adjacent Pontiac Subprovince and the Lacorne block within the SVZ, two granitic series predominate: (1) A syntectonic to late-tectonic monzodiorite–monzonite–granodiorite–syenite (MMGS) series (2690–2670 Ma) is comparable to the Abitibi SMG and SS series in most major-element, LILE, and REE contents but is distinguished by high MgO contents, extremely high Ba/Th ratios, and coenrichment of Cr, Co, and Ni with light rare-earth elements (LREE), Li, and Cs. (2) A garnet–muscovite–granite (GMG) series (2644 ± 13 Ma) displays K2O/Na2O ≥ 1, restricted SiO2 range (69–75 wt.%), pronounced enrichments of Rb, Li, Cs, Ta, Nb, Th, and U, and moderately fractionated REE's (La/Ybn = 16–0.9), with prominent negative Eu anomalies.The synvolcanic TTG series is interpreted to have formed by differentiation of low-K mafic magmas of the Blake River Group type in suprasubduction-zone environments. Geochemical compositions of the TGGM, SGM, SS, and MMGS series resemble those of Phanerozoic granitoids in island-arc settings and reflect a transition from partial melting of the subducted or subcreted slab to melting of the metasomatized depleted mantle wedge assisted by LILE- and LREE-enriched fluids released from the slab. The GMG, which formed by partial melting of the Pontiac metasediments when the Pontiac Sub-province collided with and underthrust the Abitibi SVZ at ~2670 Ma, is similar to Himalayan collisional leucogranites.
Definition and experimental determination of a soil-water retention surface
Authors: Salager S. , El Youssoufi M. S. , Saix C.
Published: May 2010

This paper deals with the definition and determination methods of the soil-water retention surface (SWRS), which is the tool used to present the hydromechanical behaviour of soils to highlight both the effect of suction on the change in water and total volumes and the effect of deformation with respect to the water retention capability. An experimental method is introduced to determine the SWRS and applied to a clayey silty sand. The determination of this surface is based on the measurement of void ratio, suction, and water content along the main drying paths. These paths are established for five different initial states. The experimental results allow us to define the parametric equations of the main drying paths, expressing both water content and void ratio as functions of suction and initial void ratio. A model of the SWRS for clayey silty sand is established in the space (void ratio – suction – water content). This surface covers all possible states of the soil inside the investigated range for the three variables. Finally, the SWRS is used to study the relations between water content and suction at a constant void ratio and between void ratio and suction at a constant water content.