bluuebunny/crossref_metadata_2025 huggingface dataset:
Crosswind stability of a high-speed train on a high embankment
Authors: Diedrichs B , Sima M , Orellano A , Tengstrand H
Published: July 2007

This work presents aerodynamic results of crosswind stability obtained numerically and experimentally for the leading control unit (class 808) of Deutsche Bahn AG's high-speed train Inter-CityExpress 2. The train model is on top of a 6m high embankment in accordance with the proposed European code for interoperable trains, the so-called technical specifications for interoperability. The purpose of the study is to convey the predictive accuracy that typical steady-state computational fluid dynamics-Reynolds average Navier-Stokes methods (industry standard) return and to contribute to the understanding of the aerodynamics for the current application.

Attention is drawn to the aerodynamics around the train and embankment when subjected to a steady block profile crosswind of 30° yaw angle on the basis of the onset velocity far upstream the embankment. The Re (Reynolds number) of the embankment cases is 4.6 × 106. Calculated results are obtained with the commercial code STAR-CD, with exclusively hexahedral meshes with a total cell count of 13.5 × 106. Results are obtained when the train stands on the windward and leeward tracks on top of the embankment. These results are first compared with a flat ground case from a previous study.

Then experimental data are obtained in a high-pressure wind tunnel with a model scale of 1:100. Re effects are compensated by raising the ambient pressure by a factor of 60, which increases the air density and thus the Re by a similar factor. Calculated results are in fair agreement with the experiments, where both the calculations and the experiments predict the leeward case to be the more critical one.

In addition, the related consequences on the mechanical behaviour, i.e. the stability of the car, are briefly addressed by means of a quasi-static mechanical analysis. The results of the present study indicate that the 6m high embankment concerning the current train reduces the permissible crosswind speed with approximately 20 per cent.
Temperatures at railway tread braking. Part 1: Modelling
Authors: Vernersson T
Published: July 2007

A thermal model of railway tread braking is developed for use in routine calculations of wheel and brake block temperatures. Two-dimensional finite-element models of block(s) and wheel are coupled via a contact interface that controls the heat generation and also the heat partitioning between block and wheel through thermal contact resistances. The surface temperature variations around the wheel circumference as caused by frictional heating and intermediate cooling are accounted for in a mean sense, assuming high-speed sliding conditions. The thermal power generated at the block-wheel interface during braking is determined from train braking data. A model for heat transfer from the rolling wheel into the rail is developed where a film with thermal contact resistance is placed at the wheel-rail contact interface. The present model can be used to efficiently design tread braking systems for both freight and passenger trains. It can handle stop braking, drag braking at constant brake power, and also intermediate periods of cooling. The temperature history during a full train route can be calculated. The inclusion of heat transfer from wheel to rail means that the model is useful for comparing brake rig tests, where normally the chilling influence from the rail is not included, with in-field tests. Two companion papers with experimental results supplement the present numerical modelling. A brief numerical example demonstrates the heat partitioning and the influence of rail chill (about 30 per cent) for two braking configurations.
Evolution of track geometric quality in high-speed lines: Ten years experience of the Madrid-Seville line
Authors: López-Pita A , Teixeira P F , Casas C , Ubalde L , Robusté F
Published: July 2007

This paper analyses the deterioration process in track geometric quality on the Madrid-Seville high-speed line, during its first ten years of commercial operation. Both the maintenance operations carried out in this period as well as all the dynamic inspection records available have been analysed. In the latter case, vertical and transversal accelerations measured on axle boxes, bogies, and vehicle bodies of Spanish high-speed trains (AVE) have been considered. The discretization of the line throughout its total extension (471 km) into 10 m long sections has made it possible to find out and quantify the relative influence of track infrastructure (tunnels, viaducts, natural subgrade, embankments, etc) on geometric track quality deterioration. The effect of switches and expansion devices in this deterioration process has also been studied.
Running resistance - results and analysis of full-scale tests with passenger and freight trains in Sweden
Authors: Lukaszewicz P
Published: July 2007

This paper presents experimental results of running resistance tests. Running resistance is determined for conventional passenger trains, freight trains, and the X2 high-speed train. The influence of variables such as speed, number of axles, number of coaches, axle load, track type, and train length is studied. The running resistance is expressed in a general form by a second degree polynomial. The three terms in the polynomial are functions of these variables. The magnitude of the first termis speed independent and varies with number of axles, axle load, and type of track. The second term varies with speed and train length. No influence of axle load is distinguished. The third term is related to the air drag and varies with the speed squared and train configuration. It can be divided into two parts. One part is constant and depends upon the front and rear of the train, and another part increases approximately linearly with train length.
Analysis of dynamic contact between overhead wire and pantograph of a high-speed electric train
Authors: Lee K
Published: July 2007

For the analysis of dynamic contact between an overhead wire and a pantograph of a high-speed train, a numerical technique for solving the equations of motion of the wire and pantograph subjected to contact condition is presented. The equations of motion of the wire and the pantograph are simultaneously time integrated with the strict application of the contact condition by the augmented Lagrange multiplier method. The velocity and acceleration contact conditions as well as the displacement contact condition are imposed with special consideration of the high-velocity contact point moving on the deformed wire. Especially, it is shown that the Coriolis and centripetal accelerations of the contact point moving rapidly on the deformed wire play the crucial roles for the stability of the solution. And, the numerical simulations are performed with a practical model consisting of suspension wire, contact wire, droppers, and pantograph.
Stress changes in the ground below ballasted railway track during train passage
Authors: Powrie W , Yang L A , Clayton C R I
Published: July 2007

The design of railway track formations has traditionally been empirically rather than analytically based, with ballast and sub-ballast layer thicknesses specified mainly on the basis of previous practice. Recent design methods are more scientifically based, and for the most advanced design methods currently in use, input parameters are typically determined from cyclic triaxial testing.

The changes in stress experienced by an element of soil below a railway track as a train passes are complex, involving (for example) a cyclic rotation of the principal stress directions. In these conditions, soil element testing in uniaxial compression may lead to the underestimation of vertical strains. Testing in a hollow cylinder apparatus, which can impose the rotations in principal stress direction likely to be experienced by a soil element in the field, may therefore be preferable to triaxial testing. However, there are as yet no data to guide the designer to a rational specification of a testing programme in this more complex apparatus.

This article reports the results of finite element analyses carried out to investigate the stress changes experienced by an element of soil beneath a ballasted railway track during train passage. The effects of element location, the initial in situ stress state of the soil, and the elastic parameters used to characterize its behaviour are investigated, and the modelling of the stress paths in a cyclic hollow cylinder apparatus is discussed.
A structural analysis of vehicle body-in-white using a substructuring technique
Authors: Kim B-G , Lee J-I , Chung T-J
Published: July 2007

A great deal of effort have been invested in improving the structural performance and feasibilities of mechanical systems, which are composed of many components. In order to analyse the complex systems, the substructuring techniques based on the behaviour of each component can widely be used in the assembly model that each component is initially incompatible and needs the feasible responses of components. In this paper, this technique is applied to the vehicle body design, and their feasibilities are verified.
Moiré interferometry applied to fracture in titanium tubes
Authors: MacKenzie P M
Published: July 2007

Despite there being a substantial body of evidence to the contrary, moiré interferometry is often regarded - even by some adherents - as a curiosity of the optics lab. The present work seeks to demonstrate still further that the method can be an effective tool for practical materials research and assessment, in this case, in a novel and challenging experimental application involving fracture testing of heat exchanger tube material, the work being conducted in a conventional materials test laboratory setting. The key to the utility of the present setup lies with the priority given to its optical efficiency.

In standard fracture toughness tests, it is axiomatic that standard specimen geometries be used. A dilemma arises when a material's properties are transformed to a substantial degree by the final stages of its process of manufacture, and when the very nature of the finished form dictates that standard geometries cannot be produced. The focus of this investigation was to measure crack-tip opening displacements (CTODs) in thin-walled titanium tubes. Fringe patterns corresponding to in-plane displacement contours were obtained interferometrically and the method for extracting CTODs from these is described. Significant differences in yield, ultimate strength, elongation, and fracture behaviour were observed for different material orientations.
1-(Chloromethyl)-4-fluoro-1,4-diazoniabicyclo-[2,2,2]octane Bis(tetrafluoroborate) as Novel and Efficient Reagent for the Conjugate Addition of Indoles to α,β-Unsaturated Ketones
Authors: Yadav J S , Reddy B V Subba , Raju A , Ravindar K , Baishya Gakul
Published: July 2007

Indoles undergo smooth conjugate addition with α,β-unsaturated ketones in the presence of 10 mol % SelectfluorTM under extremely mild conditions to afford the corresponding Michael adducts in high to quantitative yields with 1,4-selectivity.
A TBAF-mediated Chemoselective Method for Synthesis of 4-Methylbutenolides and 4-Hydroxy-4-methylbutenolides from 3-Hydroxy-4-(tert-butyldimethylsilyloxy)pentanoates
Authors: Li Chunhong , Xue Jijun , Xu Baiyan , Xie Zhixiang , Li Ying
Published: July 2007

A chemoselective synthesis of butenolides was found based on TBAF-mediated deprotection, cyclization, dehydration, and oxidation of 3-hydroxy-4-(tert-butyldimethylsilyloxy)pentanoates, which yielded either 4-methylbutenolides or 4-hydroxy-4-methylbutenolides in moderate to good yields. The selectivity depends on the quantity of TBAF. This method was applied to the synthesis of several 4-butenolide compounds.
Nickel-catalyzed Carbometalation Reactions of [2-(1-Propynyl)phenyl]methanol with 1-Alkenylmagnesium Reagents
Authors: Murakami Kei , Ohmiya Hirohisa , Yorimitsu Hideki , Oshima Koichiro
Published: July 2007

Treatment of [2-(1-propynyl)phenyl]methanol with 1-alkenyl Grignard reagents under nickel catalysis results in carbomagnesiation across the alkynyl part. The 1-alkenylation reaction proceeds in a syn fashion to yield the corresponding 1,3-butadienyl-substituted benzyl alcohol.
Orientation Control of Self-stacking d,l-Alternating Cyclic Octa-α-peptide through Multiple Electrostatic Interactions
Authors: Murota Kazutoshi , Sakamoto Seiji , Kudo Kazuaki
Published: July 2007

We designed d,l-alternating cyclic octa-α-peptides having two d-lysines and two d-glutamates as electrostatically interacting units in order to regulate the orientation of the peptide units upon stacking in an antiparallel manner. Spectroscopic analyses of the fluorescence probe on the peptide indicated the successful control of the orientation.
Comparison of the Porous Structure of Polymeric Beads Obtained by Modified Suspension and Multi-Step Swelling Polymerizations
Authors: Gawdzik Barbara , Maciejewska Małgorzata , Pikus Stanisław
Published: July 2007

The porous structures of the polymeric beads obtained by modified suspension and multi-step swelling polymerizations were studied. A porous styrene–divinylbenzene copolymer (ST–DVB) was synthesized in the modified suspension polymerization. In the multi-step polymerization, porous ST–DVB layers of the same chemical composition as obtained in the suspension polymerization were embedded onto polystyrene seed particles obtained in the first step. Three methods were used for investigating the porous structures generated. These were inverse exclusion chromatography, nitrogen adsorption and small X-ray scattering (SAXS). The former was used to characterize the polymer in the swollen state, whereas the latter two were employed with dry polymer samples. The results obtained showed that polystyrene seed particles are porous in the swollen state. However, such pores could not be detected either by nitrogen adsorption or SAXS methods.
Study of the Influence of Temperature and the Ionic Strength of the Solution on the Adsorption and Conformation of Poly(Acrylic Acid) Macromolecules on the ZrO2 Surface
Authors: Wiśniewska M.
Published: July 2007

The influence of temperature and the ionic strength of the solution on the adsorption of poly(acrylic acid) (PAA) and the structure of the corresponding adsorbed layers on a zirconium dioxide surface were studied. All measurements (spectrophotometric, electrokinetic, viscosity and potentiometric titrations) were carried out within the temperature range 15–40°C. The methods used allowed the amount of polymer adsorbed, the surface charge and diffuse layer charge of the ZrO2 particles in the absence and presence of the polymer, as well as the thickness of the polymer adsorption layers, to be determined.

The adsorption measurements demonstrated the occurrence of a minimum in PAA adsorption over the temperature range 25–30°C caused by conformational changes of the polymer macromolecules. In addition, an increase in polymer adsorption and a decrease in the thickness of the polymer adsorption layers were observed as the ionic strength of the solution increased. This was due to the fact that the repulsion interactions between the negatively charged surface and the negatively charged PAA macromolecules were screened by the NaCl used for adjusting the ionic strength.

The free energy of PAA adsorption was calculated from the zeta potential data obtained.
PTH Circadian Rhythm and PTH Target-Organ Sensitivity Is Altered in Patients With Adult Growth Hormone Deficiency With Low BMD
Authors: White Helen D , Ahmad Aftab M , Durham Brian H , Peter Rajesh , Prabhakar V Karthik B , Corlett Pamela , Vora Jiten P , Fraser William D
Published: July 2007

AGHD is associated with osteoporosis. We examined PTH circadian rhythmicity and PTH target-organ sensitivity in 23 patients with AGHD with low BMD and 20 patients with AGHD with normal BMD. Patients with low BMD had a blunted nocturnal rise in PTH concentration and reduced PTH target-organ sensitivity compared with patients with normal BMD; these factors may be important in the pathogenesis of AGHD-related osteoporosis.

Introduction: Adult growth hormone deficiency (AGHD) is associated with decreased BMD. Reduced parathyroid gland sensitivity to changes in calcium and reduced PTH target-organ sensitivity may underlie the pathogenesis of AGHD-related osteoporosis. A blunted nocturnal PTH rise has been reported in AGHD and may contribute to the reduction in BMD. We examined the difference in PTH concentration and markers of bone metabolism in patients with AGHD with normal and low BMD.

Materials and Methods: Forty-three patients with AGHD consented to the study. Twenty-five patients were growth hormone (GH) naïve (GH-N, 13 had BMD femoral neck or lumbar spine T-score < −1.0), and 18 patients had received GH for >2 yr (GH-R, 10 had BMD T-score < −1.0). Patients were hospitalized for 24 h, where blood samples were collected every 0.5 h and urine samples were collected every 3 h for PTH, calcium, phosphate, NcAMP, 1,25-dihydroxyvitamin D [1,25(OH)2D], type-I collagen β C-telopeptide (βCTX), and procollagen type-I amino-terminal propeptide (PINP). Serum calcium was adjusted for albumin (ACa).

Results: Low BMD GH-N and GH-R patients exhibited a reduced nocturnal rise in PTH concentration compared with patients with normal BMD (p < 0.001). GH-N low BMD patients had significantly higher 24-h mean PTH (p < 0.001) than GH-N normal BMD patients, with significantly lower 24-h mean NcAMP, ACa, and 1,25(OH)2D (p < 0.01), suggesting a reduction in renal PTH sensitivity. GH-R low BMD patients had significantly lower 24-h mean PTH, NcAMP, ACa, and 1,25(OH)2D (p < 0.01) than GH-R normal BMD patients, suggesting reduced renal PTH action. Lower PTH concentration in the presence of lower ACa may reflect reduced sensitivity of the parathyroid calcium-sensing receptor to changes in ACa concentration in the GH-R low BMD patients.

Conclusions: Low BMD in GH-N and GH-R AGHD patients may be a consequence of abnormalities in PTH circadian rhythmicity together with reduced parathyroid gland and target-organ sensitivity. Further studies are needed to determine the potential benefit of therapeutic manipulation of PTH rhythmicity and sensitivity on BMD.
Osteoporosis Improvement: A Large-Scale Randomized Controlled Trial of Patient and Primary Care Physician Education
Authors: Solomon Daniel H , Katz Jeffrey N , Finkelstein Joel S , Polinski Jennifer M , Stedman Margaret , Brookhart M Alan , Arnold Marilyn , Gauthier Suzanne , Avorn Jerry
Published: July 2007

We conducted a randomized controlled trial within the setting of a large drug benefit plan for Medicare beneficiaries. Primary care physicians and their patients were randomized to usual care, patient intervention only, physician intervention only, or both interventions. There was no difference in the probability of the primary composite endpoint (BMD test or osteoporosis medication) or in either of its components comparing the combined intervention group with usual care (risk ratio = 1.04; 95% CI, 0.85–1.26).

Introduction: Fractures from osteoporosis are associated with substantial morbidity, mortality, and cost. However, only a minority of at-risk older adults receives screening and/or treatment for this condition. We evaluated the effect of educational interventions for osteoporosis targeting at-risk patients, primary care physicians, or both.

Materials and Methods: We conducted a randomized controlled trial within the setting of a large drug benefit plan for Medicare beneficiaries. Primary care physicians and their patients were randomized to usual care, patient intervention only, physician intervention only, or both interventions. The at-risk patients were women ≥65 yr of age, men and women ≥65 yr of age with a prior fracture, and men and women ≥65 yr of age who used oral glucocorticoids. The primary outcome studied was a composite of either undergoing a BMD test or initiating a medication used for osteoporosis. The secondary outcome was a hip, humerus, spine, or wrist fracture.

Results: We randomized 828 primary care physicians and their 13,455 eligible at-risk patients into four study arms. Physician and patient characteristics were very similar across all four groups. Across all four groups, the rate of the composite outcome was 10.3 per 100 person-years and did not differ between the usual care and the combined intervention groups (p = 0.5). In adjusted Cox proportional hazards models, there was no difference in the probability of the primary composite endpoint comparing the combined intervention group with usual care (risk ratio = 1.04; 95% CI, 0.85–1.26). There was also no difference in either of the components of the composite endpoint. The probability of fracture during follow-up was 4.2 per 100 person-years and did not differ by treatment assignment (p = 0.9).

Conclusions: In this trial, a relatively brief program of patient and/or physician education did not work to improve the management of osteoporosis. More intensive efforts should be considered for future quality improvement programs for osteoporosis.
Local Radial Displacement Measurements of Soil Specimens in a Triaxial Test Apparatus Using Laser Transducers
Authors: Messerklinger S. , Springman S. M.
Published: July 2007

A laser scanning device is introduced to measure radial displacements in triaxial testing apparatuses. The equipment provides contactless measurement of the radial displacement of the test specimen over the whole specimen height. Additionally, a method is proposed for determining the initial specimen volume from the scanned specimen profiles as well as the change in volume during test performance. These methods are then evaluated, based on test results from a drained stress path test on Swiss lacustrine clay.
Characterizing Fatigue Response of Nickel-Titanium Alloys by Rotary Beam Testing
Authors: Patel Mitesh M.
Published: July 2007

Fatigue information has been reliable in predicting wire critical structural integrity. The aim of this study is to expound on the characterization technique of rotary beam fatigue testing (RBT). By alternating tension and compression stress states through RBT, it is possible to determine the life expectancy of Nitinol monofilament round wires. Fatigue testing has been employed to characterize the influence of subtle changes in inclusion content, chemistry variations of raw material, ingot transformation temperatures of Nitinol (NiTi), and surface finish conditions for implant grade wires. Currently, an ASTM standard does not exist that concentrates solely on fatigue testing shape memory alloys. By exploiting part geometry, this testing technique serves to compliment other characterization methods. Evaluation of fracture surfaces has proven useful in diagnosing the factors influencing failures. The utilization of fatigue data and fracture mechanics compliments tensile testing in providing information to the design engineer. Results from studying flexural endurance, statistical Weibull life assessment analysis, fracture analysis, and a determination of stress/strain levels at the site of failure have proven useful in determining desired material properties for next generation medical devices.
Martensite Transformations and Fatigue Behavior of Nitinol
Authors: Adler P. H. , Allen J. , Lessar J. , Francis R.
Published: July 2007

In addition to excellent biocompatibility and corrosion resistance, the unique flow behavior of NiTi pseudo-elastic alloys renders them ideally suited for several medical device applications utilizing minimally invasive technologies. For example, self-expanding stents are indicated chronic therapies for treatment of a variety of vascular diseases. Long-term device integrity is thus critical with the FDA recommending a minimum 10-year life. Historically, the majority of published fatigue data on NiTi alloys have been generated under strain-controlled conditions using wire or single-diamond cell samples designed to replicate the behavior of the repetitive unit within a stent. Resulting data are then presented on modified Goodman or Soderberg diagrams in order to define regions of acceptable device life. Consistent with their unusual monotonic flow characteristics these alloys are found to exhibit unique cyclic behavior in fatigue: published data clearly demonstrate that increasing mean strain often increases high-cycle fatigue life. This anomalous behavior is generally attributed to any of a number of possible microstructural or mechanical effects associated with the reversible stress-assisted austenite-to-martensite phase transformation. Although the majority of published work has focused on these macroscopic properties in order to characterize and adequately define device life, various efforts are currently underway to better understand the more fundamental metallurgical and mechanical aspects controlling fatigue life in this alloy. Such studies include crack initiation and propagation rates, determining the roles of absolute and relative inherent flow behavior of the transforming structures, mechanical instabilities resulting from the heterogeneous nature of the transformation, latent heat effects during cyclic transformation, as well as the effects of testing frequency, crystallographic texture, grain-shape anisotropy, and stress-state on fatigue life. A review of existing literature delineating these behaviors and current efforts is presented in light of known beneficial effects of transformation plasticity and toughening in enhancing fatigue and fracture properties of a variety of metallic and nonmetallic materials.
New Twist-Off Method for the Evaluation of In-Situ Strength of Concrete
Authors: Naderi M.
Published: July 2007

This paper introduces an innovative partially destructive method called “Twist-off,” for the assessment of in situ concrete strength. In this method, a 40 mm diameter metal probe is bonded to a concrete surface by means of a high strength epoxy resin adhesive. To measure the concrete compressive strength, a torque is applied using an ordinary torque wrench and the maximum torque or shear stress at failure is used to estimate the cube compressive strength by means of a calibration graph. The relationship between the results of this new method and the compressive strengths of concrete cores as well as the correlation of this method with friction-transfer method are also presented in this paper. The average coefficient of variation of the results of this method was seen to be of the order of 8 % and the correlation coefficients of its comparative results with concrete cube and core compressive strengths were found to be 0.98 and 0.90, respectively. In order to assess the performance of this method on site, tests were undertaken on a number of concrete structures. Based on these results, this method is suggested for in situ determination of concrete strength.
Enclosure, separation, and computation of the zeros of exponential trinomials with constant coefficients and real exponential points
Authors: Boese Fritz G.
Published: July 2007

After having explained the underlying motivations, we study the location of the zeros of the functions
Removable singularities of fully nonlinear elliptic equations
Authors: Schulz Friedmar
Published: July 2007

In this paper we consider fully nonlinear elliptic equations of the form

including the Monge–Ampère, the Hessian and the Weingarten equations and give conditions which ensure that a singular set
Asymptotic estimates for a semigroup related to compressible viscous fluid flow
Authors: Ströhmer Gerhard
Published: July 2007

The paper is related to the question of stability for the motionless spherically symmetric equilibrium states of viscous, barotropic, self-gravitating fluids. It considers a perturbation of the linearization of the governing equations of this problem, taking a step in the derivation of estimates which will allow us to prove non-linear stability of the equilibria. The perturbed operator, like the linearization considered earlier, generates an analytic semigroup, which allows us to derive asymptotic estimates as
Special functions and the Mellin transforms of Laguerre and Hermite functions
Authors: Coffey Mark W.
Published: July 2007

We present explicit expressions for the Mellin transforms of Laguerre and Hermite functions in terms of a variety of special functions. We show that many of the properties of the resulting functions, including functional equations and reciprocity laws, are direct consequences of transformation formulae of hypergeometric functions. Interest in these results is reinforced by the fact that polynomial or other factors of the Mellin transforms have zeros only on the critical line Re
Effects of Water Velocity and Trash Rack Architecture on Juvenile Fish Passage and Interactions: A Simulation
Authors: Floyd Emily Y. , Churchwell Roger , Cech Joseph J.
Published: July 2007

Many resident and migratory fish species have experienced population declines due to modification of estuarine ecosystems. Fish screens (or louvers) have been designed to guide fish away from the diversion pumps, and trash racks have been placed upstream of the screens to intercept aquatic plants and debris. Although small fish may aggregate around these structures, potentially increasing their vulnerability to predators, we know little about the behavior, performance, and survival of fish near trash racks. To determine how trash rack flow regime and architecture influence fish behavior, we exposed juvenile threadfin shad Dorosoma petenense and winter‐run Chinook salmon Oncorhynchus tshawytscha to three water velocities and two bar‐spacing treatments in a circular tank bisected by a simulated trash rack. Our results suggest that relatively small increases in water velocity at diversion facilities will result in the aggregation of juvenile fish near trash racks. In contrast, bar spacing did not influence fish passage frequency or interaction in this study. We also found that threadfin shad selected higher velocities as water current increased, whereas Chinook salmon consistently showed a preference for moderate to low water velocities.
A Model for Estimating Passive Integrated Transponder (PIT) Tag Antenna Efficiencies for Interval‐Specific Emigration Rates
Authors: Horton Gregg E. , Dubreuil Todd L. , Letcher Benjamin H.
Published: July 2007

Our goal was to understand movement and its interaction with survival for populations of stream salmonids at long‐term study sites in the northeastern United States by employing passive integrated transponder (PIT) tags and associated technology. Although our PIT tag antenna arrays spanned the stream channel (at most flows) and were continuously operated, we are aware that aspects of fish behavior, environmental characteristics, and electronic limitations influenced our ability to detect 100% of the emigration from our stream site. Therefore, we required antenna efficiency estimates to adjust observed emigration rates. We obtained such estimates by testing a full‐scale physical model of our PIT tag antenna array in a laboratory setting. From the physical model, we developed a statistical model that we used to predict efficiency in the field. The factors most important for predicting efficiency were external radio frequency signal and tag type. For most sampling intervals, there was concordance between the predicted and observed efficiencies, which allowed us to estimate the true emigration rate for our field populations of tagged salmonids. One caveat is that the model's utility may depend on its ability to characterize external radio frequency signals accurately. Another important consideration is the trade‐off between the volume of data necessary to model efficiency accurately and the difficulty of storing and manipulating large amounts of data.
Gastric Evacuation and Daily Ration of Naturally Produced Age‐0 Chinook Salmon in Lake Ontario
Authors: Principe Nicholas D. , Kraft Clifford E. , Mills Edward L.
Published: July 2007

Almost 30 years after natural reproduction of Chinook salmon Oncorhynchus tshawytscha was discovered in Lake Ontario tributaries, little is known about the feeding dynamics of these fish after they enter the lake. This study assesses consumption by naturally produced age‐0 Chinook salmon as they enter the nearshore region of Lake Ontario after emigrating from the Salmon River, New York, a major U.S. tributary of Lake Ontario. Evacuation rate, estimated as a function of temperature in controlled laboratory experiments, ranged from 0.214/h at 10°C to 0.352/h at 19°C. Diel field sampling for daily ration estimates occurred on three dates in late spring (June 6, 12, and 18, 2001). Although no consistent diel feeding pattern was observed, Chinook salmon maintained an elevated gut fullness value throughout the day and did not feed after dark. Moreover, daily rations (grams [dry weight] of ration per 100 g of dry fish weight), which ranged from 27.54 (SE = 3.07) on June 12 to 33.27 (3.7) on June 6, were high compared with the values obtained in similar studies. Comparisons of daily ration estimates with bioenergetics model estimates showed that juvenile Chinook salmon were consuming prey at or above their maximum estimated daily ration. Daily ring counts of sagittal otoliths confirmed that the Chinook salmon in this investigation were naturally produced. Our results indicate that current food conditions in the nearshore waters of Lake Ontario are suitable for sustaining maximum consumption rates by naturally produced juvenile Chinook salmon that have recently migrated into the lake from spawning tributaries.
Effects of Temperature and Feed Energy on the Performance of Juvenile Red Drum
Authors: Fontaine Lance P. , Whiteman Kasey W. , Li Peng , Burr Gary S. , Webb Kenneth A. , Goff Jonathan , Gatlin Delbert M. , Neill William H. , Davis Kenneth B. , Vega Robert R.
Published: July 2007

We tested the hypothesis that the growth of fish exposed to high temperatures can be limited by available food energy whereas that of fish exposed to low temperatures can be limited by their metabolic capacity to exploit the available food energy. Under laboratory conditions we evaluated growth (%/d) and marginal metabolic scope (MMS; L·g−1·h−1) of juvenile red drum Sciaenops ocellatus exposed to two levels of dietary energy, low (LE; ∼4.1 kJ/g) and high (HE; ∼15.9 kJ/g), and to three temperatures, approximately 19, 25, and 29°C, for a period of 6 weeks. Growth rate and MMS increased with temperature, but only growth rate increased with dietary energy and then only at the higher two temperatures. The simulation model Ecophys. Fish was employed to elucidate experimental results potentially confounded by interactions between fish weight and the controlling effects of temperature on metabolism. The simulated and observed results both showed that performance is enhanced at higher temperatures, especially for fish consuming the HE diet. A subsequent 6‐week‐long experiment confirmed results for fish fed the two diets at ambient temperature (∼26°C) and sought to further resolve responses by examining body condition indices and proximate composition. Additionally, these fish were assayed for differential cortisol response to 15 min of confinement stress. The feed efficiency, hepatosomatic index, intraperitoneal fat ratio, and whole‐body fat of fish fed the LE diet were significantly lower than those of fish fed the HE diet, indicating relative energy malnutrition in the LE group. As with MMS, no apparent differential effect of feed energy on the pre‐ or poststress values of plasma cortisol was observed. These findings support the ideas that red drum obtain greater metabolic capacity when they are exposed to a near‐optimal temperature and that their ability to transform that capacity into growth is maximized only when they are provided a nutritious, high‐energy diet.
A Simple Method for Estimating Survival Rate from Catch Rates from Multiple Years
Authors: Hoenig John M. , Gedamke Todd
Published: July 2007

Survival rates can be estimated from annual surveys by tracking the abundance of one or more cohorts, as measured by catch per unit of sampling effort, from one year to the next. However, it can be difficult to attain reasonable precision unless sampling effort is extensive. Indeed, estimates of survival exceeding 100% are not infrequently obtained. We show that data from several years can be analyzed simultaneously to obtain a single estimate of survival under the assumption that survival is constant over the period analyzed. The method requires that only a single cohort be identified and separated from the other age‐groups. Thus there are minimal data requirements. Estimates of the survival of goosefish Lophius americanus obtained by this method compare favorably with estimates obtained by analyzing changes in mean length over time.
Briefing: CDM 2007: out with the old, in with the new
Authors: Rabin Anna
Published: July 2007

The 1994 Construction (Design and Management) Regulations have been replaced with the all-new CDM 2007. Construction lawyer Anna Rabin of Jeffrey Green Russell highlights the key differences between the old and new regulations.
Earth systems engineering: turning vision into action
Authors: Hall Jim , O'Connell Enda
Published: July 2007

The potential of technology to help solve many of the world's most pressing problems, ranging from climate change to resource scarcity and poverty, is widely recognised. However, rationally managing and engineering the Earth's systems is a hugely complex task, which extends engineering from its traditional technical domain to dealing with coupled human and natural systems and unprecedented levels of uncertainty. It requires new understanding of how the effects of engineering accumulate and propagate across scales, up to the planetary scale. This paper surveys the challenges and principles of ‘Earth systems engineering’, as a counterpart to the already fast-developing field of Earth systems science. Examples illustrate how engineers are already applying their skills to manage complex systems such as cities, coastlines and climate.
SCOSS: safeguarding structural safety for 30 years
Authors: Carpenter John
Published: July 2007

The Standing Committee on Structural Safety (SCOSS) was formed 30 years ago to identify trends and practices in the field of structural engineering that are seen as potential causes for concern. During that time it has considered some 200 topics, some of which have led to authoritative guidance or a change in design requirements. Continuing structural failures indicate that civil and structural engineers need to remain vigilant and continue to manage risk carefully. This paper examines the work of the committee to date, the matters of concern and the major issues examined. It emphasises the need for a holistic approach to structural safety which considers the influences of people, process and product. The need to consider that human shortcomings and errors are often the root causes of failure is emphasised and illustrated.
Ten steps to managing strategic risk—a holistic approach
Authors: Allan Neil , Davis John , Godfrey Patrick
Published: July 2007

This paper presents insights and guidance for senior construction managers based on a three-year construction industry research programme called STRATrisk. The aim was to improve the way boards manage the risks that cause failure or significant loss of shareholder value. The research found a strong emphasis on behaviours and culture as the root cause of organisational complexity and investigated appropriate measures to mitigate the consequent failures. Some key principles were identified that should be applied to the management of strategic risk within the context of the relevant organisation. To assist implementation, a ten-step process has been developed from the research to help the boards and senior management of construction businesses introduce a more effective approach to managing their strategic risks.
Crack initiation in clay observed in beam bending
Authors: Thusyanthan N. I. , Take W. A. , Madabhushi S. P. G. , Bolton M. D.
Published: July 2007

Tensile cracking in clay is an important phenomenon that affects the strength and permeability of clays in many facilities, such as dams, embankments and landfill liners, as well as being a precursor to slope failures in the natural terrain. This study investigates the stress–strain criteria for cracking in clays by performing four-point bending tests on consolidated kaolin clay beams. Load-controlled and strain-controlled tests were performed on clay beams with varying initial suction to understand the stress–strain criteria for crack initiation in clay. At no stage was the negative pore pressure permitted to exceed the air entry value of the clay, so the clay remained saturated throughout. Strains in the clay were obtained by particle image velocimetry analysis of digital images of the clay beam, and suction measurements were obtained from pore pressure and tension transducers installed within the clay beams. Results from this investigation showed that the threshold tensile strain to cracking in kaolin clay decreased from about 4% at an initial mean effective stress of 15 kPa to about 1·5% at an initial mean effective stress of 100 kPa. The extreme fibre stress at failure of the clay beams indicated an effective tensile strength that was a fraction, dropping from 0·27 to 0·11 of the preconsolidation pressure as the overconsolidation ratio increased from about 2 to about 20. Alternatively, the tensile strength could be regarded as 0·45 ± 0·15 of the geometric mean of the preconsolidation pressure in the plane of shear and the initial mean effective stress. Most significantly, evidence is presented of a new understanding of cracking in clays. Cracks were seen to open either as pure tension cracks at zero minor principal effective stress, or as mixed-mode shear-tension cracks when an effective stress path reaches the Hvorslev criterion of brittle shear rupture, but only if the minor total stress is also tensile.
Geotechnical properties of Dublin Boulder Clay
Authors: Long M. , Menkiti C. O.
Published: July 2007

Geotechnical characteristics of Dublin Boulder Clay (DBC), based on detailed site investigation and site experience from some recent large projects in Dublin, are presented. This paper attempts to synthesise available information in parallel with recent work by Skipper et al., who provide an updated understanding of the geology of the DBC. Having assessed the effects of sampling disturbance, the paper characterises the various formations and sub-units of the DBC. The interpreted material behaviour is related to observed engineering performance. It was found from the behaviour of earth retained structures that intact, clayey, DBC formations are two to three times stiffer than assessed from high-quality laboratory tests on block samples. DBC is shown to be significantly stiffer than other well-characterised tills. Relatively inexpensive multichannel surface wave techniques can give very reliable estimates of in situ small-strain stiffness. High undrained triaxial compression strengths were measured, and it appears that simple UU tests on high-quality specimens give good results. Significant strength anisotropy was suggested by undrained triaxial extension strengths that were only 30–50% of the triaxial compression strengths. Field horizontal permeability values of the intact clayey till units have a representative mean of about 10−9 m/s, and when compared with laboratory values suggest that the material may exhibit some degree of anisotropy of permeability. Overall, the measured engineering parameters for the DBC are favourable for many construction projects. Further work is required in order to understand the in situ horizontal stress profile and the stiffness anisotropy of the till.
Simulating storm waves in the Irish Sea
Authors: Elliott A. J. , Neill S. P.
Published: July 2007

A third-generation wave model (PRO-WAM) has been applied to the North Atlantic and to a nested Irish Sea domain. The accuracy of the model was assessed by hindcasting storms that occurred during 1–15 January 2005 when the wind speed reached 25 m/s and wave heights of 12 m were recorded off the west coast of Ireland. The agreement between the model and the data from five offshore wave buoys was excellent at four of the five locations. An analysis of the relationship between wave height and period at the fifth site suggests that the buoy had malfunctioned. Two rapid-calculation methods for estimating a wave field were evaluated. The first method involved computing the time-invariant waves for a range of fixed wind speeds and directions then creating a look-up table for each grid cell. The second method used formulae derived from the JONSWAP spectrum. Of the two methods, the look-up table technique provided the better results. The PRO-WAM model is run operationally each day and the results stored in a data archive. The output is suitable for specifying the offshore boundary conditions for near-shore, high-resolution wave models, which could be interfaced to tidal and sediment transport models.
A new compact heat engine
Authors: Novakovic Miodrag
Published: July 2007

The Differential Cylinder Heat Engine (DCHE) reported consists of two different size cylinders with pistons where four passages (channels) enable fluid communications between cylinders. The pistons are connected in opposition to share the work. As the channels are open and closed by movement of pistons the working fluid passing through the adequate channel is heated, cooled or let adiabaticaly flown from one cylinder to the other. The arrangement enables different thermodynamic cycles to be performed. Here the Brayton cycle is chosen by adequate choice of volume ratio and by positioning the channel apertures. During isobaric parts of the cycle the gas is adequately heated or cooled when passing through corresponding channel. During these process temperatures remain constant (and different) in each cylinder. The performance of the engine is analyzed and the parameters and efficiency determined.
Pressure fluctuations in gas fluidized beds
Authors: Leckner Bo , Palchonok Genadij , Johnsson Filip
Published: July 2007

The pressure fluctuations in a fluidized bed are a result of the actions of the bubbles. However, the bubbles may be influenced by the air supply system and by the pressure drop of the air distributor. These interactions are treated for low as well as for high velocity beds by means of a simple model of the principal frequency of the pressure fluctuations. The model includes the interaction with the air supply system and describes qualitatively two important bubbling regimes: the single bubble regime, important for systems with low pressure drop air distributors, and the exploding bubble regime for high velocity beds. .
Drying of solutions and suspensions in the modified spouted bed with draft tube
Authors: Arsenijevic Zorana , Grbavcic Zeljko , Garic-Grulovic Radmila
Published: July 2007

A modified spouted bed dryer with inert particles was used for drying of solutions and suspensions. The effects of the operating conditions on dryer throughput and product quality were investigated. Experiments were performed in a cylindrical column 215 mm in diameter and 1150 mm in height with a draft tube 70 mm in diameter and 900 mm length. The bed was made of polyethylene particles 3.3 mm in diameter and of density of 921 kg/m3. The pesticide Cineb, inorganic compound calcium carbonate, organic compound calcium stearate, and pure water were used as feeding materials. A drying model using the continuity and momentum equations for turbulent accelerating two-phase flow and conventional rate equations is proposed and discussed. The work is relevant for estimating dryer performance.
Effect of temperature on a free energy and equilibrium constants during dry flue gas desulphurisation chemical reactions
Authors: Kuburovic Milos , Djuric Slavko , Jovovic Aleksandar , Karan Milenko
Published: July 2007

During dry flue gas desulphurisation (FGD) dry particles of reagents are inserted (injected) in the stream of flue gas, where they bond SO2. As reagents, the most often are used compounds of calcium (CaCO3, CaO or Ca(OH)2). Knowledge of free energy and equilibrium constants of chemical reactions during dry FGD is necessary for understanding of influence of flue gas temperature to course of these chemical reactions as well as to SO2 bonding from flue gases.