bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of pore initiation in metal foams by synchrotron-radiation tomography
Authors: Helfen L. , Baumbach T. , Pernot P. , Cloetens P. , Stanzick H. , Schladitz K. , Banhart J.
Published: May 2005

Synchrotron-radiation tomography was used to investigate early foaming stages of aluminium alloys. Monochromatic radiation, high spatial resolution down to the micrometer scale, partial beam coherence, and holographic reconstruction techniques permit the distinction between different foam constituents which are not visible by other volume imaging techniques. In combination with three-dimensional image analysis, the differences in the pore initiation processes in two different aluminium alloys are shown. We find that, in powder compacts made from prealloyed AA6061 alloy powder, pores appear predominantly around the blowing agent particles whereas, in compacts made from a powder blend of Al and Si, pores tend to initiate around Si particles.
An array of Eiffel-tower-shape AlN nanotips and its field emission properties
Authors: Tang Yongbing , Cong Hongtao , Chen Zhigang , Cheng Huiming
Published: May 2005

An array of Eiffel-tower-shape AlN nanotips has been synthesized and assembled vertically with Si substrate by a chemical vapor deposition method at 700 °C. The single-crystalline AlN nanotips along [001] direction, including sharp tips with 10–100 nm in diameter and submicron-sized bases, are distributed uniformly with density of 106–107tips∕cm2. Field emission (FE) measurements show that its turn on field is 4.7 V/μm, which is comparable to that of carbon nanotubes, and the fluctuation of FE current is as small as 0.74% for 4 h. It is revealed this nanostructure is available to optimize the FE properties and make the array a promising field emitter.
Evidence of native oxides on the capping and substrate of Permalloy gratings by magneto-optical spectroscopy in the zeroth- and first-diffraction orders
Authors: Antos Roman , Mistrik Jan , Yamaguchi Tomuo , Visnovsky Stefan , Demokritov Sergej O. , Hillebrands Burkard
Published: May 2005

Magneto-optical Kerr effect (MOKE) spectroscopy in the zeroth- and first-diffraction orders at polar magnetization is applied to Permalloy wire gratings deposited on Si substrates and protected by Cr capping. The experimental MOKE data are compared with data simulated using the local modes method. The extensive simulations of the MOKE spectroscopic parameters exhibit significant sensitivity to t(Cr2O3) and t(SiO2), the thicknesses of native oxide layers developed on the capping and the substrate, respectively. The approach may be useful for monitoring the basic micromagnetic properties of small elements with nanometer-scale resolution, as well as for monitoring the deposition processes and aging of magnetic nanostructures in magnetic recording and magnetic random access memory technologies.
Efficient chemical oxygen-iodine laser powered by a centrifugal bubble singlet oxygen generator
Authors: Nikolaev V. D. , Svistun M. I. , Zagidullin M. V. , Hager G. D.
Published: May 2005

Efficient production of singlet delta oxygen in a bubble singlet oxygen generator (BSOG) under the influence of centrifugal acceleration, 136g, has been obtained. An output power of 770W with chemical efficiency of 25.6% has been achieved in a small-scale, supersonic chemical oxygen-iodine laser supplied by the centrifugal BSOG. The ratio of the output power to the basic hydrogen peroxide volumetric flow rate was 4.3KJ∕liter. Efficient chemical oxygen-iodine laser (COIL) operation with the centrifugal BSOG demonstrates the potential for mobile COIL applications.
Effects of salt stress on growth, nodulation, and nitrogen and carbon fixation of ten genetically diverse lines of chickpea (Cicer arietinum L.)
Authors: Singh Bhupinder , Singh Binod Kumar , Kumar Jitender , Yadav Shyam Singh , Usha K.
Published: May 2005

Salinity is one of the major environmental constraints affecting agriculture in major regions of the world. It is known to depress greatly the growth and symbiotic performance of nodulated legumes. In the present study conducted over 2 rabi (dry) seasons, 2000–01 and 2001–02, 10 genetically diverse chickpea lines were compared for salt tolerance in terms of growth, nodulation, moisture content, and nodule nitrogen and carbon fixation. Chickpea lines were raised in an open-air chamber in soil supplied with 0, 50, 75, and 100 mm NaCl. The shoot, root, and the single-plant weight declined with increasing level of salt. Chickpea lines BG-1075 (desi type) and BGD-70 (Kabuli type) showed better plant growth than the former 2 lines but were poorer in nodulation under salt stress. An almost identical pattern of salt response was observed for nodule number, weight per nodule, nitrogen, and carbon fixation among the chickpea lines. No distinct relationship was found among root/shoot ratio, plant moisture content, and salt tolerance response of the chickpea. However, nodulation capacity (number and mass) under salt stress was related to salt tolerance response of chickpea lines. This trait could be used for improvement of salt tolerance of this legume species in order to increase its productivity and stability in saline soils.
Interaction of dietary iron and vitamin A influences the performance of broilers
Authors: Zhang Chunshan , Jiang Junfang , Zhang Ying , Jia Chunyan
Published: May 2005

Avian broiler chickens (504, 1-day old) were randomly divided into 9 groups with 4 replicates per treatment, to investigate the influence of dietary Fe and vitamin A levels on production performance, immune competence, serum catalase activity, serum insulin concentration, and indicators of blood iron status such as haemoglobin concentration and red cell count. Supplemental levels were: 0, 30, and 60 mg iron/kg diet; 750, 1500, and 2700 IU vitamin A/kg diet. The results showed that the iron concentration in the basal diet was sufficient for nutritional requirements and that iron supplementation was not necessary. Dietary iron levels did not affected bodyweight gain and feed : gain (P > 0.05) during the whole period, but influenced serum insulin concentration significantly (P < 0.01), with serum insulin concentration reaching a peak for the treatment 60 mg iron/kg. The influence of dietary iron level on haemoglobin concentration and erythrocyte count was significant (P < 0.05) from 0 to 4 weeks, and on erythrocyte count from 5 to 7 weeks. Different supplemental levels of vitamin A did not influence production performance and serum antibody titre to Newcastle Disease Virus, but the influence on blood T lymphocyte levels was significant (P < 0.01). The treatment with 2700 IU vitamin A/kg resulted in lower feed : gain and higher blood T lymphocyte levels than other treatments. Dietary vitamin A levels influenced serum catalase activity significantly (P < 0.01). Catalase activity was the highest when vitamin A supplemental level was 2700 IU/kg. Dietary vitamin A levels significantly affected erythrocyte count (P < 0.01) but not haemoglobin concentration during the whole period. The interaction of iron and vitamin A significantly (P < 0.05) influenced bodyweight gain, serum antibody titre to Newcastle Disease Virus, and blood T lymphocyte levels. The interaction of iron and vitamin A significantly (P < 0.01) influenced serum catalase activity at the end of Week 7, haemoglobin concentration during the whole period, and erythrocyte count from 0 to 4 weeks.The haemoglobin concentration and erythrocyte count in the group with no Fe supplementation and 750 IU vitamin A/kg were lower than normal values. The complementary effect between iron and vitamin A improved haemoglobin concentration and erythrocyte count in broilers.
A reliable screening system for aluminium tolerance in barley cultivars
Authors: Hossain Mamun , Zhou Meixue , Mendham Neville
Published: May 2005

Aluminium (Al) toxicity in the soil is an important factor that limits the production of barley in areas with acid soil. Selection and breeding of barley cultivars tolerant to Al toxicity is one of the most useful approaches to increase productivity. A reliable screening system is very important for selecting Al-tolerant plants in a breeding program. Using a hydroponic culture technique in which all the treatments were isolated in order to minimise complex interaction between genotypes, experiments were conducted to distinguish between susceptible and tolerant cultivars. Three different methods were investigated. Two previously reported methods could not provide consistent results or detect the difference between tolerant and susceptible cultivars. A new method was developed as follows: pre-germinated seedlings (2 days at 22°C) were cultured for 3 days in nutrient solution (Al free) followed by 24 h growing in a solution with 50 or 100 µm Al, and then 48 h regrowth in Al free nutrient solution. Following this method, seminal root regrowth length (SRRL) and relative seminal root regrowth length (RSRRL) showed significant differences between tolerant and sensitive cultivars. The SRRL of the most tolerant cultivar, Dayton, was 4–8 times greater than of the sensitive cultivars and about twice as long as of the other tolerant cultivars, FM404 and Brindabella. All the sensitive cultivars showed significantly shorter SRRL or RSRRL. Both SRRL and RSRRL were found to be closely correlated with plant height, plant dry weight, and grain weight in a soil-based experiment. This method was also used to evaluate F2 populations from crosses between tolerant and susceptible cultivars. Both SRRL and RSRRL gave results consistent with the hypothesis that the tolerance was controlled by a single dominant gene.
Influence of gibberellic acid and N6-benzyladenine on the development of seed and shot berries in the seedless grape (Vitis vinifera L.) cv. Perlette
Authors: Usha K. , Kashyap D. , Singh B.
Published: May 2005

Gibberellins have been used to improve quality of grapes in several cases. However, gibberellic acid (GA) alone is not enough to improve the quality in Perlette. A field experiment was conducted on 3-year-old grape cv. Perlette trained on pergolas, to investigate the effect of bunch dipping with GA3 and N6-benzyladenine (BA) on reducing the problem of shot berries and improving the productivity of grapevines. Our observations proved that the stage of application of GA3 and BA is crucial to avoiding seed formation in seedless varieties such as Perlette for table grapes. The results showed that BA at low (10 µL/L) or high concentration (30 µL/L) at 50% of full bloom caused seed development in the seedless grape cv. Perlette, whereas no seed was formed when BA was used later at the fruit set stage. Based on our studies, we found that bunch dipping with 30 µL/L GA3 (at 50% of full bloom) and 10µL/L BA (at pea size) significantly reduced the problem of shot berries, and improved the yield and quality in grape cv. Perlette.
Simulating lucerne growth and water use on diverse soil types in a Mediterranean-type environment
Authors: Dolling P. J. , Robertson M. J. , Asseng S. , Ward P. R. , Latta R. A.
Published: May 2005

The performance of the Agricultural Production Systems Simulator (APSIM) lucerne (Medicago sativa) model was assessed by comparing calculations from APSIM with measured (or observed) data from 9 sites in Western Australia. This comparison was also to obtain new insights into lucerne production and the effect of lucerne on the water balance in this environment. APSIM accounted adequately for the temporal change in above-ground biomass production and the plant-available water (PAW) for most of the sites. The root mean square deviation (RMSD) for biomass was 1.3 t/ha for the mean observed biomass of 4.17 t/ha. The RMSD for PAW was 16 mm to a depth of 1.6–2.1 m, with the mean observed PAW of 50 mm. The good prediction of PAW was partly because critical soil parameters used in APSIM were derived from the soil water content measurements. APSIM also adequately (within the standard error) estimated evapotranspiration (Et) and drainage below the root-zone, which was measured at 2 of the sites. The analysis supports previous findings with lucerne that increased storage of carbohydrates in root reserves occurs in autumn and winter. Given that APSIM performed adequately when calibrated, it was used to simulate Et and drainage for the 7 sites in which measurements were not taken. Et in all 3 years of lucerne and drainage in Year 1 were related to the amount of rainfall. Fifty-one percent of rainfall above 230 mm was lost as water excess in Year 1 (R2 = 0.68). Drainage in Year 3 was less than drainage in Year 1, confirming previous studies that established lucerne can reduce drainage.
Genetic evaluation of crossbred lamb production. 1. Breed and fixed effects for birth and weaning weight of first-cross lambs, gestation length, and reproduction of base ewes
Authors: Fogarty N. M. , Ingham V. M. , Gilmour A. R. , Cummins L. J. , Gaunt G. M. , Stafford J. , Edwards J. E. Hocking , Banks R. G.
Published: May 2005

This is the first paper in a series that reports on a national maternal sire central progeny test program (MCPT) to evaluate the genetic variation for economically important production traits in first- and second-cross progeny of maternal and dual purpose (meat and wool) sires and the scope for genetic improvement. The MCPT program also provides direct linkages between breeds that will contribute information for across-breed genetic evaluation. Crossbred progeny by 91 sires from more than 7 maternal breeds (including Border Leicester, East Friesian, Finnsheep, Coopworth, White Suffolk, Corriedale, and Booroola Leicester) at 3 sites over 3 years with 3 link sires in common at each site and year were evaluated in this study. National estimated breeding values for the sires that were entered by industry breeders indicated that there was some selection for weight, but not other traits and the sires were generally representative of the maternal genetics available to the industry. There were 8377 base Merino and Corriedale ewes artificially inseminated with thawed-frozen semen from the 91 sires and 8193 crossbred lambs born and 6117 lambs weaned. Mixed model analyses of birth and weaning weight, lamb survival, and gestation length as well as fertility, litter size, and lamb weaning rate of the base ewes are reported. Sire breed was significant for birth weight (with a range of 4.0–4.4 kg at an average litter size of 1.8) and weaning weight (19.6–22.5 kg), as well as lamb survival (70–79%) and gestation length (147.1–150.3 days). Birth/rearing type was significant for all traits. Males were significantly heavier than females at birth and weaning, although there was no sex difference for lamb survival or gestation length when birthweight was included in the model. Pregnancy rate from the artificially inseminated base ewes varied from 40 to 84% at the 3 locations in the various years. Sire breed was significant for the number of lambs weaned per ewe lambing, but not for fetal number or litter size born. There were also significant differences in performance due to the source of the base ewes at each site.
Genetic evaluation of crossbred lamb production. 2. Breed and fixed effects for post-weaning growth, carcass, and wool of first-cross lambs
Authors: Fogarty N. M. , Ingham V. M. , Gilmour A. R. , Cummins L. J. , Gaunt G. M. , Stafford J. , Edwards J. E. Hocking , Banks R.
Published: May 2005

The study evaluated post-weaning growth, carcass characteristics, and wool production of crossbred progeny of 91 sires from more than 7 maternal breeds (including Border Leicester, East Friesian, Finnsheep, Coopworth, White Suffolk, Corriedale, and Booroola Leicester). The sires were joined to Merino and Corriedale ewes at 3 sites over 3 years with 3 link sires in common at each site and year. Post-weaning weight at an average age of 200 days of 2841 ewes and 3027 wethers was analysed using mixed model procedures. The wethers were slaughtered at an average age of 214 days and carcass weight, fat, muscle, meat colour, and ultimate pH (24 h post-slaughter) were analysed. For ewes, hogget fleece weight, yield, fibre diameter, and faecal worm egg count (FEC) were analysed. Sire breed was significant (P < 0.01), with a range of 32.8–39.0 kg for post-weaning weight, 19.1–22.8 kg for hot carcass weight, and for carcass fat levels (11.1–17.2 mm at the GR site (FatGR) and 3.4–6.5 mm at the C site, adjusted to 22 kg carcass weight), with the East Friesian cross carcasses being very lean (FatGR 11.1 mm). Sire breed was significant for eye muscle area (P < 0.01) but not for eye muscle depth, meat colour L* (brightness), or ultimate pH. Sire breed was significant (P < 0.01) for greasy and clean fleece weight (CFW), yield, and fibre diameter (FD), with ranges of 0.9 kg (CFW) and 4.6 μm (FD). Sire breed was not significant for FEC. Type of birth and rearing classification was significant for most traits. National estimated breeding values for the sires that were entered by industry breeders indicated that they covered a range of genetic merit for most traits within their respective breeds and were generally representative of the maternal genetics available in the industry. Where there were large differences between the sire mean and breed mean breeding values the effects on crossbred progeny performance would be small and not expected to affect our conclusions about the breed differences reported. The results provide lamb producers with comparative information on sire breeds for growth, carcass and wool traits. The considerable variation among individual sires within the respective breeds will be reported in later papers.
Piggery pond sludge as a nitrogen source for crops 2. Assay of wet and stockpiled piggery pond sludge by successive cereal crops or direct measurement of soil available N
Authors: Kliese Y. , Strong W. M. , Dalal R. C. , Menzies N. W.
Published: May 2005

The appropriate use of wastes is a significant issue for the pig industry due to increasing pressure from regulatory authorities to protect the environment from pollution. Nitrogen contained in piggery pond sludge (PPS) is a potential source of supplementary nutrient for crop production. Nitrogen contribution following the application of PPS to soil was obtained from 2 field experiments on the Darling Downs in southern Queensland on contrasting soil types, a cracking clay (Vertosol) and a hardsetting sandy loam (Sodosol), and related to potentially mineralisable N from laboratory incubations conducted under controlled conditions and NO3– accumulation in the field. Piggery pond sludge was applied as-collected (wet PPS) and following stockpiling to dry (stockpiled PPS). Soil NO3– levels increased with increased application rates of wet and stockpiled PPS. Supplementary N supply from PPS estimated by fertiliser equivalence was generally unsatisfactory due to poor precision with this method, and also due to a high level of NO3– in the clay soil before the first assay crop. Also low recoveries of N by subsequent sorghum (Sorghum bicolor) and wheat (Triticum aestivum) assay crops at the 2 sites due to low in-crop rainfall in 1999 resulted in low apparent N availability. Over all, 29% (range 12–47%) of total N from the wet PPS and 19% (range 0–50%) from the stockpiled PPS were estimated to be plant-available N during the assay period. The high concentration of NO3- for the wet PPS application on sandy soil after the first assay crop (1998 barley, Hordeum vulgare) suggests that leaching of NO3– could be of concern when high rates of wet PPS are applied before infrequent periods of high precipitation, due primarily to the mineral N contained in wet PPS. Low yields, grain protein concentrations, and crop N uptake of the sorghum crop following the barley crop grown on the clay soil demonstrated a low residual value of N applied in PPS.
NO3– in the sandy soil before sowing accounted for 79% of the variation in plant N uptake and was a better index than anaerobically mineralisable N (19% of variation explained). In clay soil, better prediction of crop N uptake was obtained when both anaerobically mineralisable N (39% of variation explained) and soil profile NO3– were used in combination (R2 = 0.49).
Pollination biology of oilseed poppy, Papaver somniferum L.
Authors: Miller J. A. C. , Henning L. , Heazlewood V. L. , Larkin P. J. , Chitty J. , Allen R. , Brown P. H. , Gerlach W. L. , Fist A. J.
Published: May 2005

Although poppies (Papaver somniferum L.) are one of the oldest cultivated plants relatively little is known of their pollination biology. We have investigated the relative importance of wind and insects in the pollination of poppies and identified potential insect pollinators. Wind pollination was found to be negligible, insect pollination was responsible for the majority of out-crossing, and self-pollination was the dominant mode of poppy fertilisation. Honeybees and flies were identified as the main potential cross-pollinators of Tasmanian poppies. Using a transgenic poppy field trial in which approximately 50% of the pollen grains produced were transgenic, we have determined the level of pollen-mediated gene flow by scoring over 50 000 seeds for the presence of a selectable marker gene. Gene flow was measured using a 10-m buffer area that surrounded the field trial. It was highest at 0.1 m with 3.26% of seeds found to be transgenic and declined over distance with 1.73% transgenic seeds at 0.5 m, 1.80% at 1 m, 0.86% at 2 m, 0.34% at 5 m, 0.12% at 9 m, and 0.18% at 10 m. These results demonstrate that under Tasmanian conditions, pollen-mediated gene flow occurs at modest levels in poppies that are in close proximity to each other and is most probably mediated by honeybees and flies.
Feed intake and production in sheep fed diets high in sodium and potassium
Authors: Masters David G. , Rintoul Allan J. , Dynes Robyn A. , Pearce Kelly L. , Norman Hayley C.
Published: May 2005

Salinity is a problem facing many crop and livestock producers in southern Australia. One management option is to revegetate with salt-tolerant plants suitable for animal production. These plants are often halophytic shrubs containing up to 30% ash, predominantly as sodium, potassium, or chloride.
This experiment examines the consequences of a high intake of sodium and potassium separately or together on feed intake, digestibility, liveweight change, and wool growth. Twelve groups of 6 weaner wethers were allocated to treatments according to a balanced 3 × 4 factorial design with 3 levels of added potassium (0, 0.38, and 0.77 mol/kg DM equivalent to 0, 15, and 30 g/kg DM) and 4 levels of added sodium (0, 0.87, 2.18, and 3.48 mol/kg DM, equivalent to 0, 20, 50, and 80 g/kg DM) as the chloride salts. The treatment diets were fed to sheep for 6 weeks.
Increasing sodium in the diet significantly decreased feed intake, digestibility, liveweight gain, and wool growth either as a main effect or through an interaction with potassium. Organic matter intake was reduced from 1.35 kg at the lowest levels of sodium and potassium to 0.67 kg at the highest levels. Comparing the same 2 groups, liveweight gain was reduced from 144 to 0 g/day, organic matter digestibility from 59.1% to 57.3%, and wool growth from 1.21 to 1.04 mg/cm2.day. The response surfaces indicate that production was depressed even at the lower levels of sodium, whereas high potassium depressed intake, digestibility, and liveweight gain at high levels of sodium only. The interaction between sodium and potassium was always negative at high levels of sodium, indicating that manipulation of the proportions of the 2 elements is unlikely to provide benefits for animal production when total salt levels are high. Although wool growth was depressed at high sodium and potassium, the efficiency of wool growth increased from 10.0 to 15.4 g/kg organic matter intake when the lowest and highest levels of the sodium and potassium were compared. This result may present significant opportunities for the use of saline land to grow fine wool.
Using computer simulation of the selection process and known gene information to assist in parental selection in wheat quality breeding
Authors: Wang J. , Eagles H. A. , Trethowan R. , van Ginkel M.
Published: May 2005

Determining how to choose parents and conduct selections is a critical issue in plant breeding. The genetic and breeding simulation tool QuCim can predict the outcome of a cross under a specific selection scheme, when genetic information for the targetted traits is known. In this paper, we use genetic information from Australian wheat breeding programs about glutenin, as it relates to wheat quality, to predict the outcomes from some example crosses. The 8 Silverstar sister lines used in our study are morphologically very similar, but have different values for 2 important quality traits, maximum dough resistance (Rmax) and extensibility. Supposing we intend to use Silverstar in crosses with other adapted cultivars, without losing grain quality, which sister line should we use? Under the condition that high Rmax is the major breeding objective, QuCim simulation showed that Silverstar 3 and 7 should be chosen if the other parent does not have allele b at Glu-A3 and allele d at Glu-D1. If the other parent has allele b at Glu-A3 and allele d at Glu-D1, all 8 lines can be used. If the other parent does not have allele b at Glu-A3, but has allele d at Glu-D1, Silverstar 3, 4, 7, and 8 should be used, and if the other parent has allele b at Glu-A3, but does not have allele d at Glu-D1, Silverstar 1, 3, 5, and 7 should be used. Therefore, the optimum Silverstar line depends on the alleles present at glutenin loci in the other parent. Australian wheat cultivars Krichauff and Machete have a similar value for Rmax, but they differ substantially as a donor for improving Rmax in other parents. For crosses with Australian wheat cultivar Trident, Machete is the better choice, but for crosses with the Australian wheat cultivar Westonia, Krichauff is better. In conclusion, QuCim can accurately predict the outcome from a specific cross under a selection scheme when gene information is known. It can help breeders identify the best crosses and selection methods to achieve their breeding objectives.
Cancer Risks and Mortality in Heterozygous ATM Mutation Carriers
Authors: Thompson Deborah , Duedal Silvia , Kirner Jennifer , McGuffog Lesley , Last James , Reiman Anne , Byrd Philip , Taylor Malcolm , Easton Douglas F.
Published: May 2005

Background: Homozygous or compound heterozygous mutations in the ATM gene are the principal cause of ataxia telangiectasia (A-T). Several studies have suggested that heterozygous carriers of ATM mutations are at increased risk of breast cancer and perhaps of other cancers, but the precise risk is uncertain. Methods: Cancer incidence and mortality information for 1160 relatives of 169 UK A-T patients (including 247 obligate carriers) was obtained through the National Health Service Central Registry. Relative risks (RRs) of cancer in carriers, allowing for genotype uncertainty, were estimated with a maximum-likelihood approach that used the EM algorithm. Maximum-likelihood estimates of cancer risks associated with three groups of mutations were calculated using the pedigree analysis program MENDEL. All statistical tests were two-sided. Results: The overall relative risk of breast cancer in carriers was 2.23 (95% confidence interval [CI] = 1.16 to 4.28) compared with the general population but was 4.94 (95% CI = 1.90 to 12.9) in those younger than age 50 years. The relative risk for all cancers other than breast cancer was 2.05 (95% CI = 1.09 to 3.84) in female carriers and 1.23 (95% CI = 0.76 to 2.00) in male carriers. Breast cancer was the only site for which a clear risk increase was seen, although there was some evidence of excess risks of colorectal cancer (RR = 2.54, 95% CI = 1.06 to 6.09) and stomach cancer (RR = 3.39, 95% CI = 0.86 to 13.4). Carriers of mutations predicted to encode a full-length ATM protein had cancer risks similar to those of people carrying truncating mutations. Conclusion: These results confirm a moderate risk of breast cancer in A-T heterozygotes and give some evidence of an excess risk of other cancers but provide no support for large mutation-specific differences in risk.
The critical point of CO
2
+N
2
: an experiment inspired by
Notes and Records
Authors: Ke Jie , Poliakoff Martyn
Published: May 2005

Although we have only recently become regular readers of
Notes and Records
, we believe that it must be relatively rare for an article to inspire a new experiment. However, this note describes a very recent case where it happened to us. A paper describing work by Thomas Andrews FRS on high pressure mixtures of CO
2
+N
2
prompted us to make a series of measurements using a newly developed technique for locating critical point.
The theory of natural selection of Alfred Russel Wallace FRS
Authors: Bulmer Michael
Published: May 2005

Wallace's 1858 paper ‘On the tendency of varieties to depart indefinitely from the original type’ is often thought to present a theory of natural selection identical with that of Darwin. Examination of Wallace's argument shows that it is different from Darwin's because Wallace thought that an inferior variety could coexist with a superior variety until environmental deterioration forced the extinction of the inferior one. Other interpretations of Wallace's argument are re-examined in the light of this finding.
An unusual Nobel Prize
Authors: Cahn Robert W
Published: May 2005

C.-E. Guillaume received the Nobel Prize for Physics in 1920 for the discovery and development of a pair of alloys that had characteristics invariant with temperature: one had constant length near ambient temperature, the other had constant Young's modulus. A recent analysis expresses retrospective surprise at this award: the objective of this short paper is to justify the award retrospectively, in terms of the continuing and impressive consequences of Guillaume's discoveries.
The Oxford biochemistry department in wartime, 1939–45
Authors: Ord Margery G , Stocken Lloyd A
Published: May 2005

The work done in the Department of Biochemistry in Oxford during World War II is recounted. Reference is made to the research on burns, nutrition and malaria, but it is mainly concerned with the search for antidotes to mustard gas and lewisite. The discovery of a successful antidote to lewisite is described in some detail.
Some models of viscous–inviscid interaction
Authors: Lipatov Igor
Published: May 2005

Some hydrodynamical problems in which viscous–inviscid interaction is important are analysed. These problems are: disturbances propagation in channels, three-dimensional nonlinearly disturbed flows and the blow-off phenomenon.
Three-Dimensional Numerical Simulation and Performance Study of an Industrial Helical Static Mixer
Authors: Rahmani Ramin K. , Keith Theo G. , Ayasoufi Anahita
Published: May 2005

In many branches of processing industries, viscous liquids need to be homogenized in continuous operations. Consequently, fluid mixing plays a critical role in the success or failure of these processes. Static mixers have been utilized over a wide range of applications such as continuous mixing, blending, heat and mass transfer processes, chemical reactions, etc. This paper describes how static mixing processes of single-phase viscous liquids can be simulated numerically, presents the flow pattern through a helical static mixer, and provides useful information that can be extracted from the simulation results. The three-dimensional finite volume computational fluid dynamics code used here solves the Navier-Stokes equations for both laminar and turbulent flow cases. The turbulent flow cases were solved using k-ω model and Reynolds stress model (RSM). The flow properties are calculated and the static mixer performance for different Reynolds numbers (from creeping flows to turbulent flows) is studied. A new parameter is introduced to measure the degree of mixing quantitatively. Furthermore, the results obtained by k-ω and RSM turbulence models and various numerical details of each model are compared. The calculated pressure drop is in good agreement with existing experimental data.
Experimental and Numerical Investigation on the Effects of the Seeding Properties on LDA Measurements
Authors: Algieri Angelo , Bova Sergio , De Bartolo Carmine
Published: May 2005

The characteristics of the seeding particles, which are necessary to implement the laser Doppler anemometry (LDA) technique, may significantly influence measurement accuracy. LDA data were taken on a steady-flow rig, at the entrance of the trumpet of the intake system of a high-performance engine head. Five sets of measurements were carried out using different seeding particles: samples of micro-balloons sieved to give three different size ranges (25–63μm,90–200μm, and standard as received from the manufacturer 1–200μm), smoke from a “home-made” sawdust burner (particle size ⩽1μm), and fog from a commercial device (particle size around 1μm). The LDA data were compared with the results of two-phase computational fluid dynamics simulations. The comparison showed a very good agreement between the experimental and numerical results and confirmed that LDA measurements with particle dimensions in the order of 1μm or less represent the actual gas velocity. On the contrary, quite large particles, which are often used because of their cost and cleanliness advantages, introduce non-negligible errors.
Optimum Bifurcating-Tube Tree for Gas Transport
Authors: Liu Tianshu
Published: May 2005

This paper describes optimality principles for the design of an engineering bifurcating-tube tree consisting of the convection and diffusion zones to attain the most effective gas transport. An optimality principle is formulated for the diffusion zone to maximize the total diffusion mass-transfer rate of gas across tube walls under a constant total-volume constraint. This optimality principle produces a new diameter distribution for the diffusion zone in contrast to the classical distribution for the convection zone. In addition. this paper gives a length distribution for an engineering tree based on an optimality principle for minimizing the total weight of the tree under constraints of a finite surface and elastic criteria for structural stability. Furthermore, the optimum branching angles are evaluated based on local optimality principles for a single bifurcating-tube branch.
Growth of Binary Alloyed Semiconductor Crystals by the Vertical Bridgman-Stockbarger Process with a Strong Magnetic Field
Authors: LaPointe Stephen J. , Ma Nancy , Mueller D. W.
Published: May 2005

This paper presents a model for the unsteady species transport for the growth of alloyed semiconductor crystals during the vertical Bridgman-Stockbarger process with a steady axial magnetic field. During growth of alloyed semiconductors such as germanium-silicon (GeSi) and mercury-cadmium-telluride (HgCdTe), the solute’s concentration is not small, so that density differences in the melt are very large. These compositional variations drive compositionally driven buoyant convection, or solutal convection, in addition to thermally driven buoyant convection. These buoyant convections drive convective transport, which produces nonuniformities in the concentration in both the melt and the crystal. This transient model predicts the distribution of species in the entire crystal grown in a steady axial magnetic field. The present study presents results of concentration in the crystal and in the melt at several different stages during crystal growth.
Controlling Turbulence in a Rearward-Facing Step Combustor Using Countercurrent Shear
Authors: Forliti David J. , Strykowski Paul J.
Published: May 2005

The present work describes the application of countercurrent shear flow control to the nonreacting flow in a novel step combustor. The countercurrent shear control employs a suction based approach, which induces counterflow through a gap at the sudden expansion plane. Peak turbulent fluctuation levels, cross-stream averaged turbulent kinetic energy, and cross-stream momentum diffusion increased with applied suction. The control downstream of the step operates via two mechanisms: enhanced global recirculation and near field control of the separated shear layer. The use of counterflow also enhances three dimensionality, a feature that is expected to be beneficial under burning conditions.
Influence of Bulk Fluid Velocity on the Efficiency of Electrohydrodynamic Pumping
Authors: Singhal Vishal , Garimella Suresh V.
Published: May 2005

The efficiency of conversion of electrical power into fluidic power in an electrohydrodynamic (EHD) pump depends on the bulk fluid velocity. An analytical formulation is developed for calculation of the efficiency of an EHD pump, with and without the presence of a superimposed flow due to an externally imposed pressure gradient. This formulation is implemented into a numerical model, which is used to investigate the effect of bulk fluid velocity on the efficiency of the EHD action. In particular, the net flow due to the combined action of EHD and a positive or negative external pressure gradient is computed. Both ion-drag pumps and induction EHD pumps are considered. Pumps based on the ion-drag principle that are studied include a one-dimensional pump, a two-dimensional pump driven by a stationary potential gradient, and another driven by a traveling potential wave. Two-dimensional repulsion-type and attraction-type induction pumping caused by a gradual variation in the electrical conductivity of the fluid is also investigated. The efficiency of EHD pumps exhibited a strong dependence on bulk fluid velocity: for the two-dimensional steady ion-drag pump, for example, the efficiency increased from less than 2% to 22% under the influence of an external pressure gradient. The corresponding increase in efficiency for a two-dimensional repulsion-type EHD pump was from 0.26% to 24.5%.
Population Balance Modeling of Turbulent Mixing for Miscible Fluids
Authors: Madras Giridhar , McCoy Benjamin J.
Published: May 2005

Blending one fluid into another by turbulent mixing is a fundamental operation in fluids engineering. Here we propose that population balance modeling of fragmentation-coalescence simulates the size distribution of dispersed fluid elements in turbulent mixing. The interfacial area between dispersed and bulk fluids controls the transfer of a scalar molecular property, for example, mass or heat, from the dispersed fluid elements. This interfacial area/volume ratio is proportional to a negative moment of the time-dependent size distribution. The mass transfer coefficient, in the form of a Damkohler number, is the single geometry- and state-dependent parameter that allows comparison with experimental data. The model results, easily realized by simple computations, are evaluated for batch and flow vessels.
Flow Study in the Impeller–Diffuser Interface of a Vaned Centrifugal
Fan
Authors: Khelladi Sofiane , Kouidri Smaïne , Bakir Farid , Rey Robert
Published: May 2005

In order to better understand the behavior of the fluid flow in vaned centrifugal fans, theoretical and experimental work has been carried out on unsteady three-dimensional (3D) flows. Particular attention is given to the flows located at the rotor–stator interface. This zone is the seat of strong interactions between the moving part and the fixed part. This phenomenon has as consequences: Strongly unsteady flow, fluctuating forces on the stator blades, and an efficiency decrease. This work is part of a project which main objective is the aeroacoustic optimization of high speed centrifugal fans. We present in this paper the first results, mainly aerodynamic ones, which will be used thereafter as an input data to aeroacoustic modeling. A numerical simulation tool was used in order to determine the kinematics and the dynamics of these flows. The measurements of the steady and unsteady flow characteristics allowed a comparison of the theoretical and experimental results.
Laminar Flow Across a Bank of Low Aspect Ratio Micro Pin Fins
Authors: Koşar Ali , Mishra Chandan , Peles Yoav
Published: May 2005

Pressure drops and friction factors associated with the forced flow of de-ionized water over staggered and in-line circular/diamond shaped micro pin-fin bundles 100μm long with hydraulic diameter of 50 and 100μm have been experimentally investigated over Reynolds number ranging from 5 to 128. Pin fins were arranged according to two different horizontal and vertical pitch ratios (1.5 and 5). The applicability of conventional scale correlations to evaluate micro flow tests results has been assessed. It is shown that the available large-scale correlations do not adequately predict the pressure drop obtained at the micro scale. A modified correlation, based on the experimental results obtained using micro scale devices, has been proposed. The refined correlation accounts for fin density and the endwall effects encountered in micro scale configurations.
Unsteady Numerical Simulations of Turbulence and Coherent Structures
in Axial Flow Near a Narrow Gap
Authors: Chang D. , Tavoularis S.
Published: May 2005

Axial flow in a rectangular channel containing a cylindrical rod has been simulated numerically by solving the unsteady Reynolds-averaged Navier–Stokes equations with a Reynolds stress model. The time- and phase-averaged mean velocity and turbulent stresses are in fair agreement with previous experimental results in a similar configuration. The study further documents the formation of quasi-periodic coherent structures in the form of vortex pairs and the important role that they play in transporting fluid across the gap region.
Slot Jet Impinging On A Concave Curved Wall
Authors: Gilard Virginie , Brizzi Laurent-Emmanuel
Published: May 2005

In order to study the aerodynamics of a slot jet impinging a concave wall, flow visualizations, velocity measurements by particle image velocimetry (PIV) (mean velocity fields and the Reynolds stresses) and mean pressure measurements were carried out. Among the studied parameters is the effect of the relative curvature of the wall, in particular the low curvature radius because of the presence of three semistable positions. It is the first time that this type of behavior is observed in fluid mechanics. Thus three flow modes are observed and their behaviors are described. These different behaviors modify considerably the impinging jet structure and the turbulence values. Finally, from the pressure measurements, we were able to determine a criterion that allows us to know the behavior of the jet.
The Effects of Polymer Solution Preparation and Injection on Drag Reduction
Authors: Fore R. Sun Chee , Szwalek J. , Sirviente A. I.
Published: May 2005

The understanding of drag reduction by injection of polymer solutions requires an adequate and accurate polymer solution preparation process as well as a thorough understanding of the effects that the delivery system might have on the polymer flow. Mass production of polymer solutions for engineering applications could be more cost effective if large batches of highly concentrated polymer solutions are prepared and then diluted to the final concentrations of interest. However, as shown in this study, depending on the type of polymer used this procedure might be more or less adequate. This study also corroborates that the presence of macro-molecular polymer structures induced by injecting highly concentrated polymer solutions into a shear flow translates into a drag increase and substantial degradation endurance especially at high Reynolds numbers in comparison to homogeneous polymer solutions.
Two-Dimensional Pipe Model for Laminar Flow
Authors: Brunelli M. C. P.
Published: May 2005

The one-dimensional Zielke model of the energy loss in laminar pipe flow is exact but gives no information about the velocity profile. Here a two-dimensional pipe model is presented which gives the two-dimensional velocity profile in the time domain for an unstationary pipe flow of a compressible fluid that follows an equation of state. The continuity and the motion equations are projected over two sets of functions accounting for the radial and the axial dependence. A set of ordinary differential equations for the time-dependent coefficients is obtained, which is numerically integrated according to the boundary conditions at the pipe ends needed in practical applications. The model reproduces the experimental results of a water hammer and the analytical transfer functions over a wide range of frequencies.
On the Physics of Flow Separation Along a Low Pressure Turbine Blade Under Unsteady Flow Conditions
Authors: Schobeiri Meinhard T. , Öztürk Burak , Ashpis David E.
Published: May 2005

The present study, which is the first of a series of investigations dealing with specific issues of low pressure turbine (LPT) boundary layer aerodynamics, is aimed at providing detailed unsteady boundary flow information to understand the underlying physics of the inception, onset, and extent of the separation zone. A detailed experimental study on the behavior of the separation zone on the suction surface of a highly loaded LPT-blade under periodic unsteady wake flow is presented. Experimental investigations were performed at Texas A&M Turbomachinery Performance and Flow Research Laboratory using a large-scale unsteady turbine cascade research facility with an integrated wake generator and test section unit. To account for a high flow deflection of LPT-cascades at design and off-design operating points, the entire wake generator and test section unit including the traversing system is designed to allow a precise angle adjustment of the cascade relative to the incoming flow. This is done by a hydraulic platform, which simultaneously lifts and rotates the wake generator and test section unit. The unit is then attached to the tunnel exit nozzle with an angular accuracy of better than 0.05°, which is measured electronically. Utilizing a Reynolds number of 110,000 based on the blade suction surface length and the exit velocity, one steady and two different unsteady inlet flow conditions with the corresponding passing frequencies, wake velocities and turbulence intensities are investigated using hot-wire anemometry. In addition to the unsteady boundary layer measurements, blade surface pressure measurements were performed at Re=50,000, 75,000, 100,000, and 125,000 at one steady and two periodic unsteady inlet flow conditions. Detailed unsteady boundary layer measurement identifies the onset and extent of the separation zone as well as its behavior under unsteady wake flow. The results presented in ensemble-averaged and contour plot forms contribute to understanding the physics of the separation phenomenon under periodic unsteady wake flow. Several physical mechanisms are discussed.
Mass Flow Rate Controlled Fully Developed Laminar Pulsating Pipe Flows
Authors: Ray S. , Ünsal B. , Durst F. , Ertunc Ö. , Bayoumi O. A.
Published: May 2005

Pressure gradient driven, laminar, fully developed pulsating pipe flows have been extensively studied by various researchers and the data for the resultant flow field are available in a number of publications. The present paper, however, concentrates on related flows that are mass flow driven, i.e., the flows where the mass flow rate is prescribed as ṁ=ṁM+ṁAfm(t) and fm(t) is periodically varying in time. Sinusoidal and triangular mass flow rate pulsations in time are analytically considered in detail. Results of experimental investigations are presented and are complemented by data deduced from corresponding analytical and numerical studies. Overall, the results provide a clear insight into mass flow rate driven, laminar, fully developed pulsating pipe flow. To the best of the authors’ knowledge, flows of this kind have not been studied before experimentally, analytically and numerically.