bluuebunny/crossref_metadata_2025 huggingface dataset:
ETHANOL‐INDUCED SUPEROXIDE RADICALS IN FETAL CORTICAL NEURONS: CELLULAR ROS NETWORK
Authors: Jamali Amina E , Pate W. , Hess E. , Henderson G , Ahuja SK. , Clark RA. , Maffi SK
Published: June 2008

Alcohol exposure to the developing brain compromises both neurons and glial functions. While neurons are considered the primary targets, microglia may play a neurotoxic role in this process. Previous studies demonstrated that neuron death is due to oxidative stress and mitochondrially mediated (Intrinsic). These studies showed a rapid increase (within minutes) in reactive oxygen species (ROS). Due to the diffusive nature of ethanol and multiple sources of free radicals, we sought to determine the primary source of superoxide targeted by ethanol. Confocal studies of neurons suggest that the superoxide radicals may originate from the mitochondria. Using whole neurons in a luminol‐based chemiluminescence assay (Diogenes) we detected superoxide radicals in the extracellular mileu. We observed a two‐three fold transient increase in the steady state generation of superoxide radicals between 20 minutes to one hour of ethanol exposure (4mg/ml). However, the presence of Rotenone (mitochondrial complex I inhibitor) and DPI (an inhibitor of all flavinoids) blocked the release of these superoxide radicals. Interestingly, cortical microglia treated identically with ethanol, showed a greater than five fold increase in superoxide generation with a maximum at one hour. Moreover, since ethanol is known to induce hydrogen peroxide generation, it was used as a mimetic. Hydrogen peroxide also induced the production of superoxide different time kinetics. Thus, together these data demonstrate that ethanol induces the steady state production of superoxide radicals in the extracellular mileu in a mitochondrial dependent manner. Since NOX2 an NADPH oxidase is expressed in neurons, it is a potential candidate for the secondary sites of superoxide generation. The ROS network between mitochondria and the plasma membrane highlights new therapeutical targets to counter ethanol toxicity.
SAFETY OF DEXTROAMPHETAMINE AND COCAINE COMBINATIONS IN COCAINE USERS
Authors: Murff William , Roache John D.
Published: June 2008

Two studies evaluated the safety and abuse liability of d‐amphetamine in combination with cocaine in twenty cocaine‐using research volunteers maintained in a controlled research laboratory. The first study tested low doses of d‐amphetamine (15 mg) administered orally as a 1.5‐hr pretreatment before low intranasal doses (48 mg) of cocaine. The study was double‐blind, double‐dummy, and placebo‐controlled. A dose run‐up procedure was employed to maximize safety. All drug effects were modest and the main finding of the study was diminished subjective effects of cocaine on a replicate determination of the original cocaine dose. The second study examined higher doses of d‐amphetamine (30 mg, p.o.) and cocaine (96 mg, i.n.), alone and in combination, without a gradual dose run‐up. Cocaine alone increased subjective mood, cocaine craving, and ratings indicating cocaine abuse potential. Again, replicate administration of cocaine produced lesser subjective effects than the first dose. D‐amphetamine alone increased systolic and mean arterial pressures, but produced minimal effects on subjective mood. The combination of d‐amphetamine and cocaine never produced effects greater than cocaine alone except for one subject who had an asymptomatic hypertensive episode. The data are interpreted in light of the possible use of stimulants for the treatment of cocaine dependence.
IS THERE BEHAVIORAL EVIDENCE FOR CONSTITUTIVE ACTIVITY AT 5‐HT2A RECEPTORS?
Authors: France Charles P , Unzeitig Alison , Javors Martin A , Rice Kenner C , Li Jun‐Xu
Published: June 2008

There are several demonstrations of constitutive receptor activity whereby receptor signaling occurs in the absence of ligand binding. Under such conditions, drugs can increase (agonist), decrease (inverse agonist), or have no effect (neutral antagonist) on receptor signaling. To test whether drug discrimination can be used to study these three different drug actions, separate groups of rats (n=8/group) were trained to discriminate between saline and either an agonist (1‐(2,5‐dimethoxy‐4‐methylphenyl)‐2‐aminopropane [DOM], 0.56 mg/kg), an inverse agonist (MDL100907, 0.1 mg/kg), or a neutral antagonist (ketanserin, 1.0 mg/kg) at serotonin (5‐HT)2A receptors, the primary site of action for many hallucinogens. Stimulus control was adequate for testing in all three groups after an average of 33‐35 training sessions. The discriminative stimulus effects of DOM were attenuated by MDL100907 and by ketanserin and the discriminative stimulus effects of MDL100907 and ketanserin were attenuated by DOM. Neither MDL100907 nor ketanserin occasioned DOM‐lever responding and DOM did not occasion MDL100907‐ or ketanserin‐lever responding. Ketanserin occasioned >90% MDL100907‐lever responding whereas MDL100907 occasioned only 50% ketanserin‐lever responding. However, the combination of MDL100907 and the alpha2 adrenergic receptor antagonist prazosin occasioned >90% ketanserin‐lever responding, suggesting that the ketanserin discriminative stimulus comprises 5‐HT and alpha2 adrenergic components. That a ketanserin discrimination was established indicates that it is not acting as a neutral antagonist at 5‐HT2A receptors, that constitutive activity is not significant under these conditions, or that it has effects by antagonism of endogenous 5‐HT. Depletion of 5‐HT in these rats failed to provide convincing evidence for constitutive activity at 5‐HT2A receptors. CPF is supported by a Senior Scientist Award (DA17918).
SUBSTANCE USE AMONGST FEMALE SURVIVORS OF DOMESTIC VIOLENCE SURVIVORS RESIDING AT SHELTERS
Authors: Fowler Dawnovise , Faulkner Monica
Published: June 2008

Purpose:  This study examined substance use problems among women residing at a domestic violence shelter in Austin, TX. Prior studies have examined substance abuse among survivors of intimate partner abuse who were in substance abuse treatment programs. There is a shortage of studies on substance abusing women in domestic violence shelters.

Methods:  Data were collected during structured interviews with eligible women residing at a domestic violence shelter in Austin, Texas. A total of 101 women were interviewed and included in this analysis. Convenience sampling was used to identify women willing to participate in the study. Participants were recruited through their caseworkers at the shelter as well as flyers and posters describing the study. Each participant received a $20 grocery store gift card as compensation for their time. Women were eligible to participate if they were over 18 years of age, understood and spoke English and reported substance use based on their responses to the CAGE‐AID. One positive response to a CAGE‐AID question qualified the woman to participate in this study.

Findings:  Preliminary results show high rates of substance abuse and dependence. Nearly 60% of the women interviewed were alcohol dependent and 55% were drug dependent. Marital status, race and age were found to be predictors of alcohol and drug use. Additional analysis showed that the victims’ substance use was not related to the severity or extent of physical and non‐physical violence.

Conclusions:  These results reveal a strong need for substance abuse intervention for women who enter domestic violence shelters.
RESEARCH TO PRACTICE: THE VALUE OF ENGAGING YOUTH IN ADAPTING SUBSTANCE ABUSE PREVENTION INTERVENTIONS
Authors: Holleran Steiker Lori K. , Goldbach Jeremy T.
Published: June 2008

Youth who have already started using drugs and/or alcohol, are often “too late” for Universal and Selective prevention and “too soon” for intensive treatment (Eggert, 1996). Studies have long supported the belief that youth who are not motivated for change will typically not respond favorably to interventions, and it is recommended that stage‐based, tailored interventions be utilized with at risk and drug‐initiated youth (Werch, 2001). Important cultural differences exist in each agency, which clearly show a need for research on how adaptation can create attitudinal and behavioral shifts in youth.

This presentation will summarize Holleran Steiker's K01 which found that by involving youth as drug and alcohol experts in the context of their culture, a prevention curriculum can be systematically tailored to include true‐to‐life experiences of the youth, making it culturally relevant and more effective for their peers (Holleran Steiker, 2008). Holleran Steiker found not only that the youth who adapt are easily engaged; animatedly discussing the payoffs and downsides of drugs and alcohol, but also that the groups that received the culturally adapted versions had better outcomes than those that received the original curricula or no intervention (Holleran Steiker, 2008). Serendipitous qualitative findings showed that the youth engaged in adaptation reported changes in attitudes towards drugs and alcohol and changes in substance use. Discussion of the implications of this study will show the audience the need for further research in the area of cultural adaptation in prevention practice.
Outcome assessment of routine medical practice in handling child urinary tract infections: estimation of renal scar incidence
Authors: Bremberg Sven G , Edström Stella
Published: June 2008

Objective A major aim of the treatment of urinary tract infections in children is to prevent renal scars. We have studied the renal scar incidence in a defined population in order to assess the quality of the medical handling of these infections.

Design Retrospective, population‐based study. Records of children with renal scars were identified by means of hospital and health district register.

Sample All children under 16 years of age (average number 55 971) residing in a Stockholm county health district in 1990–95.

Results The incidence of children with renal scars was 9.3 per 100 000 child–years, with a possible range from 7.5 to 11. The medical handling was close to optimal; e.g. the median time between the debut of symptoms and treatment with antibiotics was 48 hours.

Conclusion The incidence of renal scars was as high as in previous studies from the 1960s and 1990s, in spite of improved quality of medical care. The incidence of renal scars in children did not seemed to be related to the quality of medical care as per this regime. This finding calls into question the assumption that further improvement of medical care of urinary tract infections might prevent permanent renal damage. Estimation of renal scar incidence, used as a method for outcome quality assessment, is not recommended until the aetiology of renal scars in children is better understood.
Reduced expression of the adhesion protein tensin1 in cultured human dermal fibroblasts affects collagen gel contraction
Authors: Saintigny Gaëlle , Bernard François‐Xavier , Juchaux Franck , Pedretti Nathalie , Mahé Christian
Published: June 2008

Abstract:  As revealed by immunohistochemistry and RT‐QPCR, the focal adhesion protein tensin1 is expressed in cultured human dermal fibroblasts and reduced by 60% after transfection with tensin1 siRNA. Tensin1 silenced fibroblast exhibited a strongly reduced capacity to contract collagen gels. Aged fibroblasts, generated with the Hayflick replicative senescence model, exhibit as siRNA silences fibroblasts, a reduced tensin1 expression and an impaired gel contraction capacity. Based on these results, we speculate that in human dermal fibroblasts, tensin1 plays an important role in cell–matrix interaction and that a reduced expression might contribute to the dermal alterations observed during skin ageing.
The response to sulpiride in major depression before and after cognitive behavioural therapy: D2 receptor function
Authors: Bell Caroline , Bhika Shamina , Porter Richard , Frampton Chris , Carter Janet , McIntosh Virginia , Jordan Jenny , Joyce Peter
Published: June 2008

Background:

Previous studies have suggested that antidepressant treatment of depression may potentiate dopamine transmission through increased sensitivity of postsynaptic D2 receptors.

Method:

D2 receptor function was assessed in 24 patients with major depression before and 16 patients after 16 weeks of treatment with cognitive behavioural therapy (CBT) using a challenge with a selective D2 antagonist, sulpiride. Four hundred milligrams of sulpiride was administered orally on two test days and response was measured by the change in prolactin levels and changes in self-rating scale measures of mood, anxiety and pleasure.

Results:

The prolactin response to sulpiride (as measured by the maximum prolactin level) was significantly increased after CBT (z = −2.792, p = 0.005). Sulpiride resulted in an improvement on mood ratings on both test days, but after CBT, this effect was significantly diminished as measured by the Profile of Mood States score (t = −2.27, p = 0.038).

Conclusions:

After 16 weeks of CBT, we detected an enhanced prolactin response to sulpiride, suggesting an increased sensitivity of D2 receptor functioning.
Identification of a glycosphingolipid transfer protein GLTP1 in Arabidopsis thaliana
Authors: West Gun , Viitanen Lenita , Alm Christina , Mattjus Peter , Salminen Tiina A. , Edqvist Johan
Published: June 2008

Arabidopsis thaliana At2g33470 encodes a glycolipid transfer protein (GLTP) that enhances the intervesicular trafficking of glycosphingolipids in vitro. GLTPs have previously been identified in animals and fungi but not in plants. Thus, At2g33470 is the first identified plant GLTP and we have designated it AtGTLP1. AtGLTP1 transferred BODIPY‐glucosylceramide at a rate of 0.7 pmol·s−1, but BODIPY‐galactosylceramide and BODIPY‐lactosylceramide were transferred slowly, with rates below 0.1 pmol·s−1. AtGLTP1 did not transfer BODIPY‐sphingomyelin, monogalactosyldiacylglycerol or digalactosyldiacylglycerol. The human GLTP transfers BODIPY‐glucosylceramide, BODIPY‐galactosylceramide and BODIPY‐lactosylceramide with rates greater than 0.8 pmol·s−1. Structural models showed that the residues that are most critical for glycosphingolipid binding in human GLTP are conserved in AtGLTP1, but some of the sugar‐binding residues are unique, and this provides an explanation for the distinctly different transfer preferences of AtGLTP1 and human GLTP. The AtGLTP1 variant Arg59Lys/Asn95Leu showed low BODIPY‐glucosylceramide transfer activity, indicating that Arg59 and/or Asn95 are important for the specific binding of glucosylceramide to AtGLTP1. We also show that, in A. thaliana, AtGLTP1 together with At1g21360 and At3g21260 constitute a small gene family orthologous to the mammalian GLTPs. However, At1g21360 and At3g21260 did not transfer any of the tested lipids in vitro.
ArHsp22, a developmentally regulated small heat shock protein produced in diapause‐destined Artemia embryos, is stress inducible in adults
Authors: Qiu Zhijun , MacRae Thomas H.
Published: June 2008

Diapause embryos of the crustacean Artemia franciscana exhibit extreme stress tolerance, a property thought to involve molecular chaperones known as small heat shock proteins. To further explore this idea, the structure, function and synthesis of ArHsp22, an Artemia small heat shock protein, were characterized. ArHsp22 contains amino‐terminal WXDPF motifs, an α‐crystallin domain with a highly conserved arginine, and a carboxy‐terminal I/VXI/V motif, all typical of small heat shock proteins. ArHsp22 formed large oligomers and exhibited molecular chaperone activity in vitro, protecting citrate synthase and insulin from denaturation. Quantitative PCR and immunoprobing of western blots revealed that ArHsp22 synthesis is restricted to diapause‐destined Artemia embryos and that the protein is degraded during post‐diapause development. ArHsp22 was observed in cyst nuclei, a location shared by p26 but not ArHsp21, which are two other diapause‐specific Artemia small heat shock proteins. ArHsp22 production was enhanced by thermal stress, but only in adults, thus representing the first crustacean small heat shock protein whose synthesis is known to be both developmentally regulated and stress inducible. The results demonstrate that expression of the gene for ArHsp22 is modulated by multiple cues that vary with life history stage. Such findings are of importance in understanding diapause maintenance in Artemia embryos and the survival of adult animals experiencing environmental insult.
Activation of PMCA by calmodulin or ethanol in plasma membrane vesicles from rat brain involves dissociation of the acetylated tubulin/PMCA complex
Authors: Monesterolo Noelia E. , Santander Verónica S. , Campetelli Alexis N. , Arce Carlos A. , Barra Héctor S. , Casale Cesar H.
Published: June 2008

We have recently shown that acetylated tubulin interacts with plasma membrane Na+,K+‐ATPase and inhibits its enzyme activity in several types of cells. H+‐ATPase of Saccharomyces cerevisiae is similarly inhibited by interaction with acetylated tubulin. The activities of both these ATPases are restored upon dissociation of the acetylated tubulin/ATPase complex. Here, we report that in plasma membrane vesicles isolated from brain synaptosomes, another P‐type ATPase, plasma membrane Ca2+‐ATPase (PMCA), undergoes enzyme activity regulation by its association/dissociation with acetylated tubulin. The presence of acetylated tubulin/PMCA complex in membrane vesicles was demonstrated by analyzing the behavior of acetylated tubulin in a detergent partition, and by immunoprecipitation experiments. PMCA is known to be stimulated by ethanol and calmodulin at physiological concentrations. We found that treatment of plasma membrane vesicles with these reagents induced dissociation of the complex, with a concomitant restoration of enzyme activity. Conversely, incubation of vesicles with exogenous tubulin induced the association of acetylated tubulin with PMCA, and the inhibition of enzyme activity. These findings indicate that activation of synaptosomal PMCA by ethanol and calmodulin involves dissociation of the acetylated tubulin/PMCA complex. This regulatory mechanism was shown to also operate in living cells.
Globins and hypoxia adaptation in the goldfish, Carassius auratus
Authors: Roesner Anja , Mitz Stephanie A. , Hankeln Thomas , Burmester Thorsten
Published: June 2008

Goldfish (Carassius auratus) may survive in aquatic environments with low oxygen partial pressures. We investigated the contribution of respiratory proteins to hypoxia tolerance in C. auratus. We determined the complete coding sequence of hemoglobin α and β and myoglobin, as well as partial cDNAs from neuroglobin and cytoglobin. Like the common carp (Cyprinus carpio), C. auratus possesses two paralogous myoglobin genes that duplicated within the cyprinid lineage. Myoglobin is also expressed in nonmuscle tissues. By means of quantitative real‐time RT‐PCR, we determined the changes in mRNA levels of hemoglobin, myoglobin, neuroglobin and cytoglobin in goldfish exposed to prolonged hypoxia (48 h at Po2 ∼ 6.7 kPa, 8 h at Po2 ∼ 1.7 kPa, 16 h at Po2 ∼ 6.7 kPa) at 20 °C. We observed small variations in the mRNA levels of hemoglobin, neuroglobin and cytoglobin, as well as putative hypoxia‐responsive genes like lactate dehydrogenase or superoxide dismutase. Hypoxia significantly enhanced only the expression of myoglobin. However, we observed about fivefold higher neuroglobin protein levels in goldfish brain compared with zebrafish, although there was no significant difference in intrinsic myoglobin levels. These observations suggest that both myoglobin and neuroglobin may contribute to the tolerance of goldfish to low oxygen levels, but may reflect divergent adaptive strategies of hypoxia preadaptation (neuroglobin) and hypoxia response (myoglobin).
Long‐term biomechanical properties after collagen crosslinking of sclera using glyceraldehyde
Authors: Wollensak Gregor , Iomdina Elena
Published: June 2008

Purpose:  Chemical crosslinking by glyceraldehyde has been shown to increase significantly the biomechanical rigidity of sclera. It might therefore become an option for a sclera‐based treatment of progressive myopia. The present pilot study was designed to test the long‐term biomechanical efficiency of the new crosslinking method.

Methods:  Six Chinchilla rabbits were treated with sequential sub‐Tenon’s injections of 0.15 ml 0.5 m glyceraldehyde, which were given in the supero‐nasal quadrant of the right eye (OD) five times over 14 days. The rabbits were killed 4 months and 8 months after crosslinking treatment, respectively. Biomechanical stress–strain measurements of scleral strips from the treatment area were performed and compared to non‐treated contralateral control sclera using a microcomputer‐controlled biomaterial testing device. In addition, the eyes were examined histologically by light microscopy to evaluate possible side‐effects.

Results:  Following the crosslinking treatment, the ultimate stress was 10.2 ± 2.3 MPa after 4 months and 8.5 ± 2.2 MPa after 8 months versus 2.4 ± 0.3 MPa in the controls (increases of 325% and 254.17%, respectively); Young’s modulus was 104.6 ± 13.7 MPa after 4 months and 53.2 ± 5.2 MPa after 8 months versus 9.6 ± 1.3 MPa in the controls (increases of 989.6% and 554.17%, respectively); and ultimate strain was 15.8 ± 1.5% after 4 months and 24.1 ± 0.7% after 8 months versus 38.4 ± 4.6% in the controls (decreases of 58.84% and 37.24%, respectively). Histologically, no side‐effects were found.

Conclusion:  Our new method of scleral collagen crosslinking proved very efficient in increasing scleral biomechanical strength over a period of up to 8 months. Glyceraldehyde can be applied easily by sequential parabulbar injections. Before clinical application in myopic patients, a study in an animal myopia model is recommended.
Improved Methods for the Prediction of Chatter in Turning, Part 1: Determination of Structural Response Parameters
Authors: Minis I. E. , Magrab E. B. , Pandelidis I. O.
Published: June 2008

The dynamics of the structure of a lathe at the cutting point are directly identified under normal machining operation using an improved version of a method originally proposed by Opitz and Weck. The improved method is based on the interrupted cutting of a specially designed, surface-modulated workpiece that provides a strong, broadband excitation. This interrupted cutting has been theoretically shown to permit the identification of the structure’s dynamics from input-output measurements, despite the intrinsic coupling of the structure with the cutting process during machining. All three components of the cutting force and the tool’s acceleration are measured simultaneously. It was found that the input force components were correlated, so that measurements from two distinct cutting configurations had to be used to obtain the elements of the structure’s transfer matrix. The modal parameters measured during the interrupted cutting tests were compared to the results of commonly used impact tests, which can only be applied when there is no cutting. This study showed that the damping of the machine tool’s structure increases during cutting by 20 to 40 percent of that measured by impact testing.
Application of Three Dimensional Finite Element Analysis to Shape Rolling Processes
Authors: Park J. J. , Oh S. I.
Published: June 2008

In the present investigation, an FEM code SHPROL has been developed for three-dimensional simulations of shape rolling processes. SHPROL is capable of handling arbitrary roll profiles and follows the deformation path incrementally so that even the end deformation that causes the crop loss can be predicted. At the present time, SHPROL can be applied to isothermal rolling processes which consist of two equivalent rolls. The rigid-viscoplastic formulation is used and the constant shear friction, variable between sticking and frictionless, is utilized at the roll-billet interface. The roll profile is described as a combination of straight lines and arcs. To demonstrate the simulation capability of SHPROL, three rolling processes have been simulated: plane-strain rolling, plate rolling, and shape rolling from square to oval cross-section. Discussions were mostly made by comparing the simulation results to general observations in practice. The results show that SHPROL is a valuable tool for designing rolling processes in industrial importance.
A Study of Air-Jet Texturing Nozzles: The Effects of Nozzle Configuration on the Air Flow
Authors: Demir A.
Published: June 2008

A thorough investigation of the existing texturing nozzles will, no doubt, lead to the design of improved nozzles. This paper reports the experimental research carried on the scaled-up versions of the T100 HemaJet with varying geometrical configurations, being the exit shape, situation, and inclination of the inlet holes, and the ratio of the incoming holes area to the nozzle’s main duct area. It has been found that the exit shape has virtually no effect on the airflow whilst other parameters contribute to the formation of the emerging jet which performs the texturing.
Performance of a New Type of Water Jet Pump
Authors: Yano H. , Funaki J. , Shinoki T. , Kieda A. , Simotori S.
Published: June 2008

A new type of water jet pump called the bend-type jet pump was investigated both theoretically and experimentally for its performance, with the primary and secondary fluids both being water. The jet pump of this type with comparatively low area ratios is promising to transport liquid containing large particles. Valuable data are given to show its performance characteristics.
A New Approach to Automatic Detection of Life of Coated Tool Based on Acoustic Emission Measurement
Authors: Moriwaki T. , Tobito M.
Published: June 2008

Characteristic features of acoustic emission (AE) signals are analyzed and measured during turning of medium carbon steel with both coated and uncoated tools. It was found that the AE signal changes from burst-type to continuous-type as the coated tool is worn away and the ceramic coating is removed. The AE signal further changes to one with a large amplitude and variation as the tool approaches termination. A procedure is proposed to classify the AE signal into three categories based on the experimental results and to identify the condition of tool by AE signal measured employing the pattern recognition technique. Further cutting experiments proved that the state of wear and the life of the coated tool can be identified by the method proposed.
Machining Chatter of End Mills With Unequal Modes
Authors: Ismail F. , Vadari V. R.
Published: June 2008

This paper further investigates the effect of reducing the contribution of the mode coupling mechanism to machining chatter. This reduction was achieved in a previous investigation by making the cutting tool more compliant in one direction. Thus, in particular, the objective of the present work was to study the effect of varying the orientation angle between the flexible mode and the leading edge of the first cutting tooth. The study covered slotting and half immersion, up and down milling. The modified cutters, irrespective of the orientation angle, are shown to outperform the regular cutter in slotting over a wide speed range. This angle is found to have a very strong effect in half immersion. The study is conducted using both computer simulation and cutting tests using aluminum.
Deep Drawing With Blank Holder Force Approximately Proportional to the Punch Force
Authors: Thiruvarudchelvan S. , Lewis W. G.
Published: June 2008

A new method of applying blank holding force approximately proportional to the punch force in cup drawing is presented. An annular urethane pad compressed between two parts of a punch expands and applies pressure against the tubular part of a blank holder. As the punch moves to draw the blank, friction between the urethane pad and the blank holder applies automatically a blank holding force approximately proportional to the punch force. Experimental investigations were carried out with aluminum blanks to determine the optimum conditions to obtain wrinkle-free cups. Variations of the punch force and the blank holding force with punch stroke for aluminum blanks under different degrees of wrinkling are presented. Strains on the cup wall measured with this method are presented and compared with those obtained under constant blank holding force conditions. Theoretical critical blank holding pressure variation with punch stroke is compared with the pressure variation that obtains with the present method. Using the deep drawing theory an expression to predict the punch force with this method is also presented.
Mechanics of Thin-Walled Tube Cropping
Authors: Rao R. S.
Published: June 2008

This paper examines the mechanisms of thin-walled tube cropping and the necessary equipment and tooling to minimize the cross-sectional distortion of billets. Tube cropping experiments identify the main process parameters that influence the quality of billets; the material of the tube and its size, as the application of a compressive preload before and during the process in the direction perpendicular to cropping also reduces the distortion of the billets. The large plastic deformation suffered by the billet up to the point of peak load is verified by a theoretical model based on plastic work calculations. Peak cropping loads are correlated with the standard tensile tests using von Mises criterion of yielding. Finally, some bar feed mechanisms and billet weight/volume control techniques are discussed for the purpose of developing a computer-controlled on-line system. The practical application of this research would be in nuclear reprocessing where there is a need to extract irradiated fuel from thin-walled steel tubes.
Model-based Control for Three-Roll Bending Process of Channel Bar
Authors: Yang Ming , Shima Susumu , Watanabe Tohru
Published: June 2008

A three-roll bending process with an automatic control system for producing a bar with a U-shaped cross section is studied. The relationship between the bending moment and the curvature of the workpiece is calculated by an elementary method. The calculated relationship is used to build up a process model combining the geometry of the three-roll bending process. This process model is applied to a real time control system for the process. Experiments are performed with the aid of a control system for obtaining products with a constant curvature as well as with continuously varying curvature. The desired curvatures are obtained with good accuracy.
Verification of Strip Drawing Analysis Using New Sapphire Dies
Authors: Rao R. S.
Published: June 2008

In this paper a simple analysis of strip drawing, including the influence of back tension on drawing force, is developed and verified by experiments using new sapphire dies and traditional carbide dies. The simple analysis provides a good estimate of forces and pressures acting on the dies and would be considered as a quick alternate to the solutions based on the more expensive finite element methods. It is found from experiments that friction is less for sapphire compared with carbide [1]. Although sapphire is an attractive die material because it fulfills certain wear requirements and has low friction, it is a brittle material. In order to withstand cold metal drawing, it should be supported by a high-strength steel holder. Such design considerations are also presented to facilitate the use of sapphire dies in practical applications.
A New Hydraulic Pressure Intensifier Using Oil Hammer
Authors: Suzuki Katsumasa
Published: June 2008

An oil hammer generates a greater pressure than that supplied to a pipeline, and sometimes causes equipment breakdown. The author intends to actively utilize this pressure rise. A new type of pressure intensifier is proposed, which converts oil pressure into a value more than six times higher, by means of an oil hammer. The intensifier has advantages in simple structure and in easy control since it is controllable by switching only one solenoid operated valve. A theoretical analysis describing the performance and operation of this design is developed. Results of experimental work on this design are then compared with theoretical results.
Design and Uncertainty Analysis of a Series of Atomization Experiments in Seven Variables
Authors: Ruiz F. , Chigier N. A.
Published: June 2008

Atomization of liquids is a phenomenon that involves many variables. In order to find correlations for the effects of an extended set of variables, dimensional analysis and experimental design are used, resulting in experimental plans with very reduced number of necessary data points. Means were found to further reduce the cost of the experiments by adjustments of the ranges of the variables and the selection of the parameters and experimental sources of variability. The generation and propagation of uncertainties in the experiments are discussed, and estimates for the true lack of fit of the approximations obtained are found. The selection of a quadratic polynomial approximation seems adequate, given the relative magnitude of the other sources of uncertainty. The effects of some dimensionless parameters with physical meaning are isolated for the first time.
Flow in a Rotating Straight Pipe, With a View on Coriolis Mass Flow Meters
Authors: Durst F. , Raszillier H.
Published: June 2008

The fully developed flow through a straight pipe, which rotates about an axis perpendicular to its own, is considered. The perturbation of the Hagen-Poiseuille flow, produced by the pipe rotation, is computed to second order and its features are described. The force of the fluid on the rotating pipe is correlated with other parameters of the flow, among them the mass flow rate Q˙. Possible relevance of the flow field and of the fluid forces in the rotating pipe for Coriolis flow meters are discussed.
Viscous Damping of Stationary Wave Formed Near an Obstacle in a Channel
Authors: Katoh K. , Fujita H.
Published: June 2008

The purpose of this study is to investigate surface wave damping due to viscosity. The stationary wave formed near an obstacle in a horizontal channel is chosen as the subject of this analysis because gravitational and surface tension waves appear separately before and behind the obstacle, and, hence, the effect of viscosity on two typical kinds of waves can be analyzed. The linearized differential equation for the stream function is solved analytically to obtain the waveform. The calculated damping rate of wave amplitude does not agree well with that of Stokes’ approximate estimation. This shows that the Stokes’ estimation is not sufficient, and that an exact analysis as presented here is necessary when the Reynolds number is as low as Re≦ 1000. As an application of this analysis, the waveform is calculated for the stationary wave formed by an obstacle in falling liquid film flow.
Numerical Study of Turbulent Secondary Flows in Curved Ducts
Authors: Hur N. , Thangam S. , Speziale C. G.
Published: June 2008

The pressure driven, fully developed turbulent flow of an incompressible viscous fluid in curved ducts of square cross-section is studied numerically by making use of a finite volume method. A nonlinear K -1 model is used to represent the turbulence. The results for both straight and curved ducts are presented. For the case of fully developed turbulent flow in straight ducts, the secondary flow is characterized by an eight-vortex structure for which the computed flowfield is shown to be in good agreement with available experimental data. The introduction of moderate curvature is shown to cause a substantial increase in the strength of the secondary flow and to change the secondary flow pattern to either a double-vortex or a four-vortex configuration.
Analysis of Transient Pressures in Bubbly, Homogeneous, Gas-Liquid Mixtures
Authors: Chaudhry M. Hanif , Bhallamudi S. Murty , Martin C. Samuel , Naghash M.
Published: June 2008

Flow of a gas-liquid mixture in a piping system may be treated as a pseudo-fluid flow if the mixture is homogeneous and the void fraction is small. The governing equations for such flows are a set of nonlinear partial differential equations with pressure dependent coefficients. Shocks may be produced during transient state conditions. For numerical integration of these equations, two second-order explicit finite-difference schemes are introduced. To verify validity of the computed results, they are compared with the experimental results.
A Numerical Study of Wall Shear Stress of Viscous Flows in Curved Atherosclerotic Tubes
Authors: Liu Biyue
Published: June 2008

Atherosclerosis is a disease of large- and medium-size arteries, which involves complex interactions between the artery wall and the blood flow. Both clinical observations and experimental results showed that the fluid shear stress acting on the artery wall plays a significant role in the physical processes which lead to atherosclerosis [1,2]. Therefore, a sound understanding of the effect of the wall shear stress on atherosclerosis is of practical importance to early detection, prevention and treatment of the disease. A considerable number of studies have been performed to investigate the flow phenomena in human carotid artery bifurcations or curved tubes during the past decades [3–8]. Numerical studies have supported the experimental results on the correlation between blood flow parameters and atherosclerosis [6–8]. The objective of this work is to understand the effect of the wall shear stress on atherosclerosis. The mathematical description of pulsatile blood flows is modeled by applying the time-dependent, incompressible Navier-Stokes equations for Newtonian fluids. The equations of motion and the incompressibility condition are ρut+ρ(u·∇)u=−∇p+μΔu,  inΩ,    (1)∇·u=0,  inΩ    (2) where ρ is the density of the fluid, μ is the viscosity of the fluid, u = (u1, u2, u3) is the flow velocity, p is the internal pressure, Ω is a curved tube with wall boundary Γ (see Figure 1). At the inflow boundary, fully developed velocity profiles corresponding to the common carotid velocity pulse waveform are prescribed u2=0,u3=0,u1=U(1+Asin(2πt/tp)),    (3) where A is the amplitude of oscillation, tp is the period of oscillation; U is a fully developed velocity profile at the symmetry entrance plane. At the outflow boundary, surface traction force is prescribed as Tijnjni=0,    (4)uiti=0    (5) where Tij=−pδij+μ(∂ui/∂xj+∂uj/∂xi)    (6) is the stress tensor, n = (n1, n2, n3) is the out normal vector of the outlet boundary. On the wall boundary Γ, we assume that no slipping takes place between the fluid and the wall, no penetration of the fluid through the artery wall occurs: u|r=nHt,    (7) where n = (n1, n2, n3) is the out normal vector of the wall boundary Γ. H is the function representing the location of the wall boundary. At initial time t = 0, H is input as shown in Figure 1. During the computation, H is updated by a geometry update condition based on the localized blood flow information. The initial condition is prescribed as u|t=0=u0,p|t=0=p0, where u0, p0 can be obtained by solving a Stokes problem: −μΔu0+∇p0=0,∇·u0=0, with boundary conditions (3)–(7) but zero in the right hand side of (7).
On the Parametric Excitation of a Nonlinear Aeroelastic Oscillator
Authors: Lumbantobing H. , Haaker T. I.
Published: June 2008

In this paper the following equation for the parametric excitation of a nonlinear aeroelastic oscillator of seesaw type is considered: θ¨+1−εa0cos(ωt)θ=εF(θ,θ˙,μ). In this equation εF represents the aeroelastic force, μ the wind velocity and ε denotes a small parameter. To study the dynamics of the oscillator we use the method of averaging. In absence of parametric excitation one typically finds that above a critical wind velocity the oscillators rest position becomes unstable and stable oscillations with finite amplitude result. Addition of the parametric excitation changes this simple picture. On changing the wind velocity local bifurcations like pitchfork, saddle-node and Hopf bifurcations lead to new nontrivial critical points and limit cycles in the averaged equations. In addition, a global saddle-connection bifurcation is found which either creates or destroys a limit cycle. Note that critical points and limit cycles in the averaged system correspond to periodic solutions and periodically modulated solutions of the original system. An analysis for the possible stability diagrams of the trivial solution and the location of bifurcations in the parameter space is presented. Finally, the numerical calculations performed match with the obtained analytical results and provide phaseportraits for some especial cases.
Effect of Pulsations on the Wake Structure of a Circular Cylinder
Authors: Konstantinidis Efstathios , Balabani Stavroula , Yianneskis Michael
Published: June 2008

The effect of flow perturbations (sinusoidal pulsations) on the wake structure of a circular cylinder in turbulent crossflow has been studied by means of LDA measurements along the wake axis. The results show the variation of the extent of the recirculation bubble and vortex formation regions and the longitudinal distance of the vortices in the von Ka´rma´n street with pulsation frequency and amplitude within the lock-on range.
The Unsteady Fluid Flow Due to Corona Discharge in a System of Wire and Plate Electrodes
Authors: Imai Yusuke , Itoh Yoshiaki , Mihira Hideyuki , Yoshizawa Masatsugu
Published: June 2008

Lateral oscillation of a wire electrode occurs when high dc voltage is applied between a wire and plate electrodes in an electrostatic field with corona discharge. The feature is that the horizontal component of the wire oscillation gradually increases and is excited with the fundamental natural frequency of the wire oscillation. We have already discussed the effects of the electrostatic and the fluid forces on the wire oscillation from the physical point of view. The fluid force on the wire due to corona wind was assumed to be one of main reasons for the outbreak mechanism of the wire oscillation. However, the outbreak mechanism of the wire oscillation has not been given yet. The main purpose of this paper is to examine another possible reason for the outbreak mechanism of the wire oscillation due to the fluid force. Some experiments are made to investigate whether oscillation of a non-conductive string, placed in the flow field, is excited by the fluid force or not. Moreover, the PIV (Particle Image Velocimetry) and the LDV (Laser Doppler Velocimeter) techniques are used to measure the flow field to confirm the hypothesis of the outbreak mechanism t hat the wire oscillation is excited due to the fluctuation of the fluid force on the wire.
A Closer Investigation of the Mean Aerodynamic Forces for Two Staggered Circular Cylinders in Cross-Flow
Authors: Sumner D. , Richards M. D.
Published: June 2008

Two circular cylinders of equal diameter in a staggered configuration, with centre-to-centre pitch ratios of P/D = 1.125 – 4.0, were tested in the subcritical Reynolds number regime, at Re = 3.0×104 – 8.0×104. The incidence angle of the cylinder configuration was varied in small increments from α = 0° – 90° and the mean aerodynamic forces were measured on both the upstream and downstream cylinders. Based on the force measurements, the behaviour of the cylinders was broadly grouped into three categories, depending on P/D. For closely spaced staggered configurations, P/D = 1.125 – 1.25, the aerodynamic forces on both the upstream and downstream cylinders varied significantly with α. Several critical incidence angles were identified for each cylinder that corresponded to local maximum, minimum, or discontinuous behaviour in the forces, which were related to shear layer reattachment and the influence of the gap flow. For moderately spaced staggered configurations, P/D = 1.5 – 2.5, shear layer reattachment and the subsequent transition to gap flow at small α were responsible for the inner lift peak, a corresponding minimum drag, and a loss of lift with increasing α, which becomes more abrupt as P/D is increased. For widely spaced staggered configurations, P/D = 3.0 – 4.0, the two cylinders undergo Ka´rma´n vortex shedding for the entire range of α. At small α, the forces on the downstream cylinder are affected by vortex impingement, and the outer lift peak replaces the inner lift peak. This outer lift peak exhibits some sensitivity to the Reynolds number.
Cross-Flow Past a Pair of Staggered Cylinders With the Upstream Cylinder Subjected to a Transverse Harmonic Oscillation
Authors: Price Stuart J. , Krishnamoorthy Srikanth , Pai¨doussis Michael P.
Published: June 2008

An experimental investigation of the cross-flow past a pair of staggered circular cylinders, with the downstream cylinder subject to forced harmonic oscillation transverse to the flow direction, is presented in this paper. In particular, flow-visualization of the wakeformation region and hot-film measurements of the wake spectra are reported. Experiments were conducted in a water tunnel for Reynolds numbers, based on upstream velocity, U, and cylinder diameter, D, in the range 1440 ≤ Re ≤ 1680. The longitudinal separation between cylinder centers is L/D = 2.0, with a transverse separation (for the mean position of the upstream cylinder) of T/D = 0.17. As shown in an earlier study, depending on the actual position of the upstream cylinder in its oscillation cycle, this configuration straddles the shear-layer reattachment and induced separation regimes. The results show that the oscillation of the upstream cylinder causes considerable modification of the flow patterns and regimes compared to what is obtained when the cylinder is fixed. In particular, depending on the frequency of oscillation of the upstream cylinder, sub- and superharmonic resonances are obtained between the vortex formation frequency and oscillation frequency, as well as the usual fundamental lock-in. These resonances and accompanying wake regimes are examined in detail in this paper.
Explicit Flow-Aligned Orientational Distribution Functions for Dilute Nematic Polymers in Weak Shear
Authors: Forest M. Gregory , Zhou Ruhai , Wang Qi
Published: June 2008

Flow-alignment of sheared nematic polymers occurs in various flow-concentration regimes. Analytical descriptions of shear-aligned nematic monodomains have a long history across continuum, mesoscopic and mean-field kinetic models, sacrificing precision at each finer scale. Continuum Leslie-Ericksen theory applies to highly concentrated, weak flows of small molecular weight polymers, giving an explicit macroscopic alignment angle formula dependent only on Miesowicz viscosities. Mesoscopic tensor models apply at all concentrations and shear rates, but explicit “Leslie angle” formulas exist only in the weak shear limit (Cocchini et. al, 90; Bhave et. al, 93; Wang, 97; Rienacker and Hess, 99; Maffettone et. al, 00; Forest and Wang, 02; Forest et. al, 02c; Grecov and Rey, 02), with distinct behavior in dilute versus concentrated regimes. Exact probability distribution functions (pdf’s) of kinetic theory do not exist for highly concentrated nematic states, even without flow, although appealing flow-aligned approximations have been derived (Kuzuu and Doi, 83; Kuzuu and Doi, 84; Semenov, 83; Semenov, 86; Archer and Larson, 95; Kroger and Seller, 95), which offer a molecular theory basis for the Leslie alignment angle. A simpler problem concerns the dilute concentration regime where the unique quiescent equilibrium is isotropic, corresponding to a constant pdf, and whose weak shear deformation is robust to mesoscopic closure approximation (Forest and Wang, 02; Forest et. al, 02c): steady, flow-aligning, weakly anisotropic, and biaxial. The purpose of this paper is to explicitly construct the weakly anisotropic branch of stationary pdf’s by a weak-shear asymptotic expansion of kinetic theory. A second-moment pdf projection confirms mesoscopic model predictions, and further yields explicit Leslie angle and degree of alignment formulas in terms of molecular parameters and normalized shear rate.