bluuebunny/crossref_metadata_2025 huggingface dataset:
Computation of Surface Electrical Potentials of Plant Cell Membranes
Authors: Kinraide Thomas B. , Yermiyahu Uri , Rytwo Giora
Published: July 2002

A Gouy-Chapman-Stern model has been developed for the computation of surface electrical potential (ψ0) of plant cell membranes in response to ionic solutes. The present model is a modification of an earlier version developed to compute the sorption of ions by wheat (Triticum aestivum L. cv Scout 66) root plasma membranes. A single set of model parameters generates values for ψ0 that correlate highly with published ζ potentials of protoplasts and plasma membrane vesicles from diverse plant sources. The model assumes ion binding to a negatively charged site (R  − = 0.3074 μmol m−2) and to a neutral site (P  0 = 2.4 μmol m−2) according to the reactions R  − +I  Ζ ⇌RI  Ζ−1 and  P  0 + I  Ζ⇌ PI  Ζ, whereI  Ζ represents an ion of charge Ζ. Binding constants for the negative site are 21,500m  −1 for H+, 20,000m  −1 for Al3+, 2,200m  −1 for La3+, 30m  −1 for Ca2+ and Mg2+, and 1 m  −1 for Na+ and K+. Binding constants for the neutral site are 1/180 the value for binding to the negative site. Ion activities at the membrane surface, computed on the basis of ψ0, appear to determine many aspects of plant-mineral interactions, including mineral nutrition and the induction and alleviation of mineral toxicities, according to previous and ongoing studies. A computer program with instructions for the computation of ψ0, ion binding, ion concentrations, and ion activities at membrane surfaces may be requested from the authors.
The Down-Regulation of Mt4-Like Genes by Phosphate Fertilization Occurs Systemically and Involves Phosphate Translocation to the Shoots1
Authors: Burleigh Stephen H. , Harrison Maria J.
Published: July 2002

Mt4 is a cDNA representing a phosphate-starvation-inducible gene from Medicago truncatula that is down-regulated in roots in response to inorganic phosphate (Pi) fertilization and colonization by arbuscular mycorrhizal fungi. Split-root experiments revealed that the expression of the Mt4 gene in M. truncatula roots is down-regulated systemically by both Pi fertilization and colonization by arbuscular mycorrhizal fungi. A comparison of Pi levels in these tissues suggested that this systemic down-regulation is not caused by Pi accumulation. Using a 30-bp region of the Mt4 gene as a probe, Pi-starvation-inducible Mt4-like genes were detected in Arabidopsis and soybean (Glycine max L.), but not in corn (Zea mays L.). Analysis of the expression of the Mt4-like Arabidopsis gene,At4, in wild-type Arabidopsis and pho1, a mutant unable to load Pi into the xylem, suggests that Pi must first be translocated to the shoot for down-regulation to occur. The data from the pho1 and split-root studies are consistent with the presence of a translocatable shoot factor responsible for mediating the systemic down-regulation of Mt4-like genes in roots.
Delivery of a Secreted Soluble Protein to the Vacuole via a Membrane Anchor1
Authors: Barrieu François , Chrispeels Maarten J.
Published: July 2002

To further understand how membrane proteins are sorted in the secretory system, we devised a strategy that involves the expression of a membrane-anchored yeast invertase in transgenic plants. The construct consisted of a signal peptide followed by the coding region of yeast invertase and the transmembrane domain and cytoplasmic tail of calnexin. The substitution of a lysine near the C terminus of calnexin with a glutamic acid residue ensured progression through the secretory system rather than retention in or return to the endoplasmic reticulum. In the transformed plants, invertase activity and a 70-kD cross-reacting protein were found in the vacuoles. This yeast invertase had plant-specific complex glycans, indicating that transport to the vacuole was mediated by the Golgi apparatus. The microsomal fraction contained a membrane-anchored 90-kD cross-reacting polypeptide, but was devoid of invertase activity. Our results indicate that this membrane-anchored protein proceeds in the secretory system beyond the point where soluble proteins are sorted for secretion, and is detached from its membrane anchor either just before or just after delivery to the vacuole.
Expression of Endoxyloglucan Transferase Genes inacaulis Mutants of Arabidopsis
Authors: Akamatsu Taku , Hanzawa Yoshie , Ohtake Yuhko , Takahashi Taku , Nishitani Kazuhiko , Komeda Yoshibumi
Published: July 2002

A mutant of Arabidopsis with reduced internodal cell length, acaulis5 (acl5), has recently been shown to have reduced transcript levels of a gene for endoxyloglucan transferase, EXGT-A1 (Y. Hanzawa, T. Takahashi, Y. Komeda [1997] Plant J 12: 863–874). In the present study, we cloned genomic fragments of five members of theEXGT gene family, EXGT-A1,EXGT-A3, EXGT-A4, XTR2, and XTR3, and examined their expression in the wild type and in a series of acl mutants. In wild-type plants, theEXGT-A3 gene showed higher expression in lower internodes (internodes between nodes bearing axillary shoots) than in upper and young internodes, in which EXGT-A1 was highly expressed. EXGT-A4 was preferentially expressed in roots and XTR3 in siliques. The XTR2 gene was constitutively expressed. In acl1, acl3, and acl4 mutants, which have a severe defect in leaf expansion as well as in internode elongation, theEXGT-A1 gene showed reduced levels of expression before bolting of plants. In contrast, XTR3 was increased in these mutant seedlings. Reduction of EXGT-A1 expression was also detected after bolting of all acl mutants except acl2, whose growth defect is restricted to lower internodes. These results suggest the involvement of each EXGT in different aspects of organ development.
Purification of a Jojoba Embryo Fatty Acyl-Coenzyme A Reductase and Expression of Its cDNA in High Erucic Acid Rapeseed
Authors: Metz James G. , Pollard Michael R. , Anderson Lana , Hayes Thomas R. , Lassner Michael W.
Published: July 2002

The jojoba (Simmondsia chinensis) plant produces esters of long-chain alcohols and fatty acids (waxes) as a seed lipid energy reserve. This is in contrast to the triglycerides found in seeds of other plants. We purified an alcohol-forming fatty acyl-coenzyme A reductase (FAR) from developing embryos and cloned the cDNA encoding the enzyme. Expression of a cDNA in Escherichia coliconfers FAR activity upon those cells and results in the accumulation of fatty alcohols. The FAR sequence shows significant homology to an Arabidopsis protein of unknown function that is essential for pollen development. When the jojoba FAR cDNA is expressed in embryos ofBrassica napus, long-chain alcohols can be detected in transmethylated seed oils. Resynthesis of the gene to reduce its A plus T content resulted in increased levels of alcohol production. In addition to free alcohols, novel wax esters were detected in the transgenic seed oils. In vitro assays revealed that B. napus embryos have an endogenous fatty acyl-coenzyme A: fatty alcohol acyl-transferase activity that could account for this wax synthesis. Thus, introduction of a single cDNA into B. napus results in a redirection of a portion of seed oil synthesis from triglycerides to waxes.
Differential Regulation of Plastidial and Cytosolic Isoforms of Peptide Methionine Sulfoxide Reductase in Arabidopsis
Authors: Sadanandom Arivananthan , Poghosyan Zaruhi , Fairbairn David J. , Murphy Denis J.
Published: July 2002

We report the characterization of two members of a gene family from Arabidopsis that encode, respectively, cytosolic (cPMSR) and plastid-targeted (pPMSR) isoforms of the oxidative-stress-repair enzyme peptide methionine sulfoxide reductase. Overexpression of these proteins in Escherichia coli confirmed that each had PMSR enzyme activity with a synthetic substrate,N-acetyl-[3H]-methionine sulfoxide, or a biological substrate, α-1 proteinase inhibitor. The pPMSR was imported into intact chloroplasts in vitro with concomitant cleavage of its approximately 5-kD N-terminal signal peptide. The two PMSR isoforms exhibited divergent pH optima, tissue localization, and responses to developmental and environmental effects. Analysis of the Arabidopsis database indicated that there are probably at least twop-pmsr-like genes and three c-pmsr-like genes in the Arabidopsis genome. Expression of thep-pmsr genes and their protein products was restricted to photosynthetic tissues and was strongly induced following illumination of etiolated seedlings. In contrast, thec-pmsr genes were expressed at moderate levels in all tissues and were only weakly affected by light. Exposure to a variety of biotic and abiotic stresses showed relatively little effect onpmsr gene expression, with the exception of leaves subjected to a long-term exposure to the cauliflower mosaic virus. These leaves showed a strong induction of the c-pmsrgene after 2 to 3 weeks of chronic pathogen infection. These data suggest novel roles for PMSR in photosynthetic tissues and in pathogen defense responses in plants.
Brassinosteroid-Insensitive-1 Is a Ubiquitously Expressed Leucine-Rich Repeat Receptor Serine/Threonine Kinase
Authors: Friedrichsen Danielle M. , Joazeiro Claudio A.P. , Li Jianming , Hunter Tony , Chory Joanne
Published: July 2002

Brassinosteroid (BR) mutants of Arabidopsis have pleiotropic phenotypes and provide evidence that BRs function throughout the life of the plant from seedling development to senescence. Screens for BR signaling mutants identified one locus, BRI1, which encodes a protein with homology to leucine-rich repeat receptor serine (Ser)/threonine (Thr) kinases. Twenty-seven alleles of this putative BR receptor have been isolated to date, and we present here the identification of the molecular lesions of 14 recessive alleles that represent five new mutations. BR-insensitive-1 (BRI1) is expressed at high levels in the meristem, root, shoot, and hypocotyl of seedlings and at lower levels later in development. Confocal microscopy analysis of full-length BRI1 fused to green fluorescent protein indicates that BRI1 is localized in the plasma membrane, and an in vitro kinase assay indicates that BRI1 is a functional Ser/Thr kinase. Among thebri1 mutants identified are mutants in the kinase domain, and we demonstrate that one of these mutations severely impairs BRI1 kinase activity. Therefore, we conclude that BRI1 is a ubiquitously expressed leucine-rich repeat receptor that plays a role in BR signaling through Ser/Thr phosphorylation.
Inward Potassium Channel in Guard Cells As a Target for Polyamine Regulation of Stomatal Movements
Authors: Liu Kun , Fu Huihua , Bei Qixin , Luan Sheng
Published: July 2002

A number of studies show that environmental stress conditions such as drought, high salt, and air pollutants increase polyamine levels in plant cells. However, little is understood about the physiological function of elevated polyamine levels. We report here that polyamines regulate the voltage-dependent inward K+ channel in the plasma membrane of guard cells and modulate stomatal aperture, a plant “sensor” to environmental changes. All natural polyamines, including spermidine, spermine, cadaverine, and putrescine, strongly inhibited opening and induced closure of stomata. Whole-cell patch-clamp analysis showed that intracellular application of polyamines inhibited the inward K+ current across the plasma membrane of guard cells. Single-channel recording analysis indicated that polyamine regulation of the K+ channel requires unknown cytoplasmic factors. In an effort to identify the target channel at the molecular level, we found that spermidine inhibited the inward K+ current carried by KAT1 channel that was functionally expressed in a plant cell model. These findings suggest that polyamines target KAT1-like inward K+ channels in guard cells and modulate stomatal movements, providing a link between stress conditions, polyamine levels, and stomatal regulation.
Regulation and Function of the ArabidopsisABA-insensitive4Gene in Seed and Abscisic Acid Response Signaling Networks
Authors: Söderman Eva M. , Brocard Inès M. , Lynch Tim J. , Finkelstein Ruth R.
Published: July 2002

We have characterized developmental, environmental, and genetic regulation of abscisic acid-insensitive (ABI)4 gene expression in Arabidopsis. Although expressed most strongly in seeds,ABI4 transcripts are also present at low levels in vegetative tissue; vegetative expression is not induced by abscisic acid (ABA) or stress treatments. Comparison of transcript levels in mature seeds of ABA-insensitive, ABA-hypersensitive, ABA-deficient, or heterochronic mutants indicates that ABI4 expression is altered in only two of the backgrounds, the ABA-insensitive mutantsabi1-1 and abi3-1. To determine whetherABI4 is necessary and/or sufficient for ABA response, we assayed the effects of loss of ABI4 function and ectopicABI4 expression on growth and gene expression. We examined genetic interactions among three ABA response loci,ABI3, ABI4, and ABI5, by comparing phenotypes of mutants, ectopic expression lines, mutants carrying an ectopically expressed transgene, and the corresponding wild-type lines. Our results indicate some cross-regulation of expression among ABI3, ABI4, andABI5 and suggest that they function in a combinatorial network, rather than a regulatory hierarchy, controlling seed development and ABA response.
The Ca2+ Status of the Endoplasmic Reticulum Is Altered by Induction of Calreticulin Expression in Transgenic Plants
Authors: Persson Staffan , Wyatt Sarah E. , Love John , Thompson William F. , Robertson Dominique , Boss Wendy F.
Published: July 2002

To investigate the endoplasmic reticulum (ER) Ca2+ stores in plant cells, we generated tobacco (Nicotiana tabacum; NT1) suspension cells and Arabidopsis plants with altered levels of calreticulin (CRT), an ER-localized Ca2+-binding protein. NT1 cells and Arabidopsis plants were transformed with a maize (Zea mays) CRT gene in both sense and antisense orientations under the control of an Arabidopsis heat shock promoter. ER-enriched membrane fractions from NT1 cells were used to examine how altered expression of CRT affects Ca2+uptake and release. We found that a 2.5-fold increase in CRT led to a 2-fold increase in ATP-dependent 45Ca2+accumulation in the ER-enriched fraction compared with heat-shocked wild-type controls. Furthermore, after treatment with the Ca2+ ionophore ionomycin, ER microsomes from NT1 cells overproducing CRT showed a 2-fold increase in the amount of45Ca2+ released, and a 2- to 3-fold increase in the amount of 45Ca2+ retained compared with wild type. These data indicate that altering the production of CRT affects the ER Ca2+ pool. In addition, CRTtransgenic Arabidopsis plants were used to determine if altered CRT levels had any physiological effects. We found that the level of CRT in heat shock-induced CRT transgenic plants correlated positively with the retention of chlorophyll when the plants were transferred from Ca2+-containing medium to Ca2+-depleted medium. Together these data are consistent with the hypothesis that increasing CRT in the ER increases the ER Ca2+ stores and thereby enhances the survival of plants grown in low Ca2+ medium.
Training needs at different organizational levels within a professional services firm
Authors: Burke Ronald J.
Published: July 2002

States that owing to a vast change in commercial activity, organizational strategy and global competition, the skills needs in the organization of the 1990s are quite different from those needed 20 years ago. In consequence, training needs have changed as well. Examines whether women and men at similar organizational levels report the same training needs; whether women and men at different organizational levels report similar or different training needs; and whether training needs reported by the most senior organizational level convey something about the culture or strategic direction of the organization. Analyses data collected from an employee survey within a single large professional services firm. Discusses the results.
Interpersonal skills and emotional maturity influence entrepreneurial style of bank managers
Authors: Avkiran Necmi
Published: July 2002

Results of this study highlight the importance of human resource managers and trainers assessing the interpersonal skills and emotional maturity of new recruits and enhancing the interpersonal skills of the existing managerial workforce. The entrepreneurial style of the branch manager is projected to play an increasingly important role in the deregulated finance sector. Currently, the branch manager, who can best be described as a corporate entrepreneur, could well evolve into an independent entrepreneur under a franchise banking system. Path analysis was used to investigate the interrelationships among the three competency factors for a bank branch manager. Emotional maturity and interpersonal skills are modelled as impacting on entrepreneurial style. All the hypothesised effects were supported by decomposition of the zero‐order correlations.
Nanotechnology update
Authors: Wittenberg G
Published: July 2002

Gives a brief description of nanotechnology and outlines various
on‐going nanotechnology projects in the UK and USA.
Four competing futures for facility management
Authors: Nutt Bev
Published: July 2002

Four generic FM “trails” to the future are explored. These trails follow the four types of resource that are basic to the FM function; the financial resource trail (business), the human resource trail (people), the physical resource trail (property) and the knowledge resource trail (information). These trail are considered in turn with speculations on the opportunities and risks that each competing future might hold. The paper concludes with nine strategic positions from which a rich, robust and diverse variety of viable futures for FM can be developed.
The System Analyst and Designer’s Vade‐Mecum, or Applicable Systematics in a Nutshell
Authors: Musès Charles
Published: July 2002

Offers the results of experience and reflection to systems analysts. Provides a list which includes: conception, component‐connection diagram, component‐connection table, and function table, of all the capabilities and operational modes considered desirable from a system, together with the component settings and activated interconnections needed to obtain those capabilities or functions.
Optimizing the reflow profile via defect mechanism analysis
Authors: Lee Ning‐Cheng
Published: July 2002

A reflow profile is proposed which is engineered to optimize soldering performance based on defect mechanism analysis. In general, a slow ramp‐up rate is desired in order to minimize hot slump, bridging, tombstoning, skewing, wicking, opens, solder beading, solder balling, and components cracking. A minimized soaking zone reduces voiding, poor wetting, solder balling, and opens. Use of a low peak temperature lessens charring, delamination, intermetallics, leaching, dewetting, and voiding. A rapid cooling rate helps to reduce grain size as well as intermetallic growth, charring, leaching and dewetting. However, a slow cooling rate reduces solder or pad detachment. The optimized profile favors that the temperature ramps up slowly until reaching about 180°C. Implementation of the optimized profile requires the support of a heating‐efficient reflow technology with a controllable heating rate. Emergence of the forced air convection reflow provides a controllable heating rate. In addition, it is not sensitive to variation in parts’ features, thus allows the realization of the optimized profile.
Creating a sustainable competitive advantage through training
Authors: Burden Rebecca , Proctor Tony
Published: July 2002

The article examines how customer needs are represented within the training evaluation framework of an organisation. The authors assert that meeting customer needs on time, every time, is a route to achieving and sustaining competitive advantage, and training is a tool that organisations should use to succeed at this. Information on good practice from the National Training Awards case studies was used as the basis of the research. The authors conclude that customers’ needs/wants are often not given the attention they deserve but that there is the potential for enhancing practice. Two gaps in the evaluation process are revealed: the ability to relate customer satisfaction to organisational aims and the ability to recognise the behavioural changes necessary to achieve these aims. The authors speculate that successful outcomes are most likely to be achieved if case‐study material is analysed rigorously, if outcomes are carefully articulated, if a range of measurement opportunities are employed and if managers are closely involved in action research processes.
Development of a curved layer LOM process for monolithic ceramics and ceramic matrix composites
Authors: Klosterman Donald A. , Chartoff Richard P. , Osborne Nora R. , Graves George A. , Lightman Allan , Han Gyoowan , Bezeredi Akos , Rodrigues Stan
Published: July 2002

A novel rapid prototyping technology incorporating a curved layer building style was developed. The new process, based on laminated object manufacturing (LOM), was designed for efficient fabrication of curved layer structures made from ceramics and fiber reinforced composites. A new LOM machine was created, referred to as curved layer LOM. This new machine uses ceramic tapes and fiber prepregs as feedstocks and fabricates curved structures on a curved‐layer by curved‐layer basis. The output of the process is a three‐dimensional “green” ceramic that is capable of being processed to a seamless, fully dense ceramic using traditional techniques. A detailed description is made of the necessary software and hardware for this new process. Also reviewed is the development of ceramic preforms and accompanying process technology for net shape ceramic fabrication. Monolithic ceramic (SiC) and ceramic matrix composite (SiC/SiC) articles were fabricated using both the flat layer and curved layer LOM processes. For making curved layer objects, the curved process afforded the advantages of eliminated stair step effect, increased build speed, reduced waste, reduced need for decubing, and maintenance of continuous fibers in the direction of curvature.
Dopamine selectively reduces GABAB transmission onto dopaminergic neurones by an unconventional presynaptic action
Authors: Federici Mauro , Natoli Silvia , Bernardi Giorgio , Mercuri Nicola B.
Published: July 2002

The functioning of midbrain dopaminergic neurones is closely involved in mental processes and movement. In particular the modulation of the inhibitory inputs on these cells might be crucial in controlling firing activity and dopamine (DA) release in the brain. Here, we report a concentration‐dependent depressant action of dopamine on the GABAB IPSPs intracellularly recorded from dopaminergic neurones. Such effect was observed in spite of the presence of D1/D2 dopamine receptor antagonists. A reduction of the GABAB IPSPs was also caused by noradrenaline (norepinephrine) and by l‐β‐3,4‐dihydroxyphenylalanine (l‐DOPA), which is metabolically transformed into DA. The DA‐induced depression of the IPSPs was partially antagonised by the α2 antagonists yohimbine and phentolamine. DA did not change the postsynaptic effects of the GABAB agonist baclofen, suggesting a presynaptic site of action. Furthermore, DA did not modulate the GABAA‐mediated IPSP. The DA‐induced depression of the GABAB IPSP occluded the depression produced by serotonin and was not antagonized by serotonin antagonists. The DA‐ and 5‐HT‐induced depression of the GABAB IPSP persisted when calcium and potassium currents were reduced in to the presynaptic terminals. These results describe an unconventional presynaptic, D1 and D2 independent action of DA on the GABAB IPSP. This might have a principal role in determining therapeutic/side effects of l‐DOPA and antipsychotics and could be also involved in drug abuse.
Pool Boiling of FC-72 and HFE-7100
Authors: Liu Z. W. , Lin W. W. , Lee D. J. , Peng X. F.
Published: July 2002

This work reported the boiling characteristics of FC-72 and HFE-7100 at atmospheric pressure and at a liquid subcooling of 0–20 K. The FC-72 exhibits a more efficient nucleate boiling mode and a higher critical heat flux (CHF) than the HFE-7100. For film boiling mode, HFE-7100 becomes more efficient.
Approximate Solution of a Class of Radiative Heat Transfer Problems
Authors: Qiao H. , Ren Y. , Zhang B.
Published: July 2002

An approximate solution is presented for a class of radiative heat transfer problems within enclosures having black or diffuse-gray surfaces based on a modified Taylor series expansion method; such radiative transfer problems are generally represented by integral equations. The approach avoids use of any boundary/initial conditions associated with the original Taylor series expansion method and leads to an approximate solution in a simple closed form to the radiant integral equations, which can be computed straightforwardly on a modern personal computer using symbolic computing codes such as Maple. The method can be effectively and efficiently applied to deal with enclosures involving more than one or two surfaces, for which direct numerical integration may be subject to instability, or require an excessive amount of computation. The computed numerical results for representative thermal problems are in excellent agreement with those obtained by other numerical approaches. [S0022-1481(00)00203-6]
Transient Double Diffusive Convection in a Vertical Enclosure With Asymmetrical Boundary Conditions
Authors: Mergui S. , Gobin D.
Published: July 2002

This study deals with the numerical analysis of transient heat and species transfer by natural convection in a binary fluid vertical layer. The cavity is differentially heated and a solutal buoyancy force is created by imposing a concentration step at one vertical wall: This refers to the experimental situation where the composition gradient inducing the solutal buoyancy force is created by melting of pure ice in a salty solution. The constitution of the flow structure and the time evolution of the heat and mass transfer characteristics are studied for opposing body forces over a range of thermal and solutal Rayleigh numbers. The numerical results allow to provide a better insight into the mechanisms driving the heat and species transfer at high Lewis number thermohaline convection. [S0022-1481(00)00303-0]
Effect of Double Dispersion on Mixed Convection Heat and Mass Transfer in Non-Darcy Porous Medium
Authors: Murthy P. V. S. N.
Published: July 2002

Similarity solution for the problem of hydrodynamic dispersion in mixed convection heat and mass transfer from vertical surface embedded in porous media has been presented. The flow induced by the density variations is comparable with the freestream flow. The heat and mass transfer in the boundary layer region for aiding and opposing buoyancies in both aiding and opposing flows has been analyzed. The structure of the flow, temperature, and concentration fields in the Darcy and non-Darcy porous media are governed by complex interactions among the diffusion rate (Le) and buoyancy ratio (N) in addition to the flow driving parameter (Ra/Pe). The flow, temperature, and concentration fields are analyzed and the variation of heat and mass transfer coefficients with the governing parameters are presented. [S0022-1481(00)00703-9]
Maximum Wave Crests in Heavy Seas
Authors: Dawson T. H.
Published: July 2002

Applicability of extreme-value theory in predicting the maximum crest amplitude in runs of ocean waves is demonstrated using data from extensive computer simulations of random linear waves. Extension of the theory to include wave crests in heavy seas is also made within the context of Stokes nonlinearities. Results are confirmed with scaled laboratory measurements. [S0892-7219(00)00803-7]
Numerical Study of the Thrust, Energy Consumption, and Propulsive Efficiency of a Three Joint Bending Propulsion Mechanism
Authors: Nakashima Motomu , Ono Kyosuke
Published: July 2002

In our previous paper, we proposed a numerical method based on the discrete vortex method for a bending propulsion mechanism of fish or cetaceans in water, and we demonstrated its validity by comparing the results with an experiment using a three joint bending propulsion mechanism. In this paper, using this numerical method, we will analyze the characteristics of the thrust, energy consumption, and propulsive efficiency of a three joint bending propulsion mechanism in terms of normalized propulsive speed and the phase differences of the adjacent joints. We found that the thrust decreases due to the increase in the lift force as the normalized propulsive speed increases when all the joints move in phase. We also found that the propulsive efficiency has a maximum value when the normalized propulsive speed is 0.8 and when all the phase differences between the joints are 100 degrees. [S0098-2202(00)01203-7]
Time Model of Rubber Deformation
Authors: Le Guen J. , Thouverez F. , Demoulin G. , Jezequel L.
Published: July 2002

In this article we present a simplified time model of elastic deformation in rubber. The originality of the method is to provide a model with very few degrees of freedom while conserving the frequential, nonlinear and energetic characteristics of the rubber. The energy dissipation of the elastomer is integrated to the structural level of the material by introducing rheological models or fractional derivatives. The representation obtained may be integrated into the complete vehicle models. It may also be applied to the conception and validation phase of an engine or vehicle suspension.
Acoustic Radiation by Point- or Line-Excited Laminated Plates
Authors: Hwang Y. F. , Kim M. , Zoccola P. J.
Published: July 2002

This paper presents an elasticity theory solution for computation of acoustic radiation by a point- or line-excited fluid-loaded laminated plate, which may consist of a stack of an arbitrary number of different isotropic material layers. A one-side water-loaded three-layer sandwich plate, which consists of a hard rubber core sandwiched between two steel plates of equal thickness, was used as an example of the laminated plates. The approximated equivalent sandwich plate solutions were compared with the elasticity theory solutions. These results show that the approximated solutions are, as expected, valid only at frequencies much lower than the coincidence frequency. The numerical result also shows that, even at about one-tenth of the coincidence frequency, the approximated solutions suffer substantial error. The differences between the dry-side- and the wet-side-excited radiated fields of a single-layer uniform plate and a sandwich plate were investigated and compared, and found to be significantly different at frequencies above the coincidence frequency. [S0739-3717(00)01803-1]
Thermal Stresses V
Authors: Hetnarski, R. B. , Allen, D. H.
Published: July 2002

[S0021-8936(00)03202-5]
Closure to “Discussion of ‘On Stability of Time-Varying Multidimensional Linear Systems’ ” [ASME J. Vibr. Acoust., 121, No. 4, pp. 509–511 (1999)]
Authors: Wu Jinn-Wen
Published: July 2002

[S0739-3717(00)00704-2]
Closure to “Discussion of ‘Estimating the Probability Distribution of von Mises Stress for Structures Undergoing Random Excitation’ ” [ASME J. Vibr. Acoust., 122, No. 1, pp. 42–48 (2000)]
Authors: Segalman, Dan , Reese, Garth , Field, Richard , Fulcher Clay
Published: July 2002

[S0739-3717(00)01404-5]
Solar Chimney Cycle Analysis With System Loss and Solar Collector Performance
Authors: Gannon Anthony J. , von Backstro¨m Theodor W.
Published: July 2002

An ideal air standard cycle analysis of the solar chimney power plant gives the limiting performance, ideal efficiencies and relationships between main variables. The present paper includes chimney friction, system, turbine and exit kinetic energy losses in the analysis. A simple model of the solar collector is used to include the coupling of the mass flow and temperature rise in the solar collector. The method is used to predict the performance and operating range of a large-scale plant. The solar chimney model is verified by comparing the simulation of a small-scale plant with experimental data. [S0199-6231(00)00503-7]
Free Vibration Analysis of Angle-ply Laminated Shallow Cylindrical Shell with Clamped Edges
Authors: Hosokawa Kenji , Murayama Minehiro , Sakata Toshiyuki
Published: July 2002

In a previous paper, the authors proposed a numerical approach for analyzing the free vibrations of a laminated FRP (fiber reinforced plastic) composite plate. In the present paper, this approach is modified for application to a symmetrically laminated shallow cylindrical shell having a rectangular planform. First, the natural frequencies of the shell are calculated for discussion of the convergence and accuracy of the solution. Next, the effects of the curvature ratio and stacking sequence on the natural frequencies and mode shapes of the shell are studied. Furthermore, to justify the numerical results, vibration tests of the clamped symmetrically laminated shallow cylindrical shell having a square planform are carried out. These experimental results are found to agree well with the numerical results computed using the measured material properties of the lamina.
Experimental and Numerical Study of Conjugate Heat Transfer in a Horizontal Channel Heated From Below
Authors: Chiu Wilson K. S. , Richards Cristy J. , Jaluria Yogesh
Published: July 2002

Conjugate heat transfer has significant relevance to a number of thermal systems and techniques which demand stringent temperature control, such as electronic cooling and chemical vapor deposition. A detailed experimental and numerical study is carried out to investigate conjugate heat transfer in a common configuration consisting of a horizontal channel with a heated section. Experimental data obtained from this study provides physical insight into conjugate heat transfer effects and facilitates validation of numerical conjugate heat transfer models. The basic characteristics of the flow and the associated thermal transport are studied. The numerical model is used to carry out a parametric study of operating conditions and design variables, thus allowing for the characterization of the conjugate heat transfer effects. It is found that the numerically predicted flow field and heat transfer results validate well to experimental observations. Conjugate heat transfer is shown to significantly affect the temperature level and uniformity at the heated section’s surface, channel walls and the gas phase, thus impacting the rate of heat transfer. This study provides guidelines and fundamental insight into temperature control during the combined modes of heat transfer, with implications to various thermal manufacturing methods.
The Effects of Tooling Imperfections on the Initiation of Wrinkling in Finite Element Modeling of a Deep Drawing Process
Authors: Hematian J. , Wild P. M.
Published: July 2002

A brief review of the literature on wrinkling in deep drawing processes is presented. It is noted that, while there is a large body of literature related to thin sheet, only one study related to thick sheet or plate has been identified. Finite element based models are used to investigate the effect of initial tooling imperfections on the initiation of wrinkling in deep drawing of thick sheet. Two sorts of tooling imperfections, punch displacement and blank tilting, are considered. The simulation results are compared qualitatively to the experimental forming operation. It is confirmed that tooling imperfections, in particular blank tilting, are an important type of imperfection governing the wrinkling behavior of the blank in deep drawing process.
Effect of Lubricant on Flyability and Read-Write Performance in the Ultra-Low Flying Regime
Authors: Ma Xiaoding , Kuo David , Chen Jianping , Tang Huan , Gui Jing
Published: July 2002

The effect of lubricant on flyability and read-write performance in ultra-low flying regime has been studied over the disks with lubricant on one half of disk surface thicker than the other half. The dynamics of a slider was monitored using Acoustic Emission (AE) and Laser Doppler Vibrometer (LDV). An instability characteristic of a slider flying over the thick lubricant region has been observed and this instability intensifies as flying height decreases and the step thickness increases. After the slider flies over the disks, it has been found that lubricant re-distribution occurs as lubricant is “carried” by the flying slider from the thick lubricant region and deposited onto the thin lubricant region. Possible mechanisms were discussed to explain the observations. Finally, recording tests were performed and the magnetic spacing loss due to the lubricant steps was estimated.
Analysis of the Immediate Boundary Conditions of an Axial Flow Impeller
Authors: Johnson David A.
Published: July 2002

The design and analysis of impellers for mixing applications such as stirred tank reactors (STR) have significant application in many engineering processes. In particular, the evaluation of the turbulent flow boundary conditions immediately around a model impeller has been examined using flow visualization, laser Doppler anemometry (LDA) and particle image velocimetry (PIV). Mean and fluctuating velocities are presented for all three velocity components. Good agreement between LDA and PIV measurements was obtained once an optimized PIV arrangement was defined. Turbulence parameters such as kinetic energy, dissipation, and length scales are estimated from the measurements. Several approaches to evaluating dissipation were used. Triggered PIV measurements were used to evaluate the variation in radial and tangential velocities in the entire planes above and below the impeller at constant axial distances. The size and orientation of the vortices shed from the impeller blade tips and the corresponding regions of high kinetic energy and dissipation indicate the importance of these structures in mixing.
Probabilistic Growth of Complex Fatigue Crack Shapes: Toward Risk Based Inspection Intervals for Railroad Tank Cars
Authors: Riddell William T.
Published: July 2002

A model for probabilistic growth of complex fatigue crack shapes that will be used to perform sensitivity studies and to optimize inspection intervals for railroad tank cars is presented. In this model, crack growth is based on results from a deterministic crack growth analysis with additional terms to introduce stochastic behavior. The family of complex shapes that cracks grow through is parameterized by a single degree of freedom, which simplifies the probabilistic model. Comparisons between experimental and numerical results suggest that the probabilistic model is capable of representing realistic crack growth using reasonable crack growth parameters, which will enable the sensitivity and optimization studies for which the model is intended.
X-Ray Microbeam Laue Pattern Studies of the Spreading of Orientation in OFHC Copper at Large Strains
Authors: Butler G. C. , Stock S. R. , McGinty R. D. , McDowell D. L.
Published: July 2002

This paper assesses, via X-ray microbeam diffraction, the effects of development of dislocation substructure on the distribution of sub-grain misorientations in annealed OFHC copper deformed to large strains for compression, for shear, and for sequences of compression followed by shear. Polychromatic synchrotron x-radiation was used to study samples from four strain histories: virgin specimens, 50% effective strain in compression, 100% effective strain in torsion, and 50% compressive strain followed by 50% torsion. A very narrow beam illuminated an approximately 15 μm diameter column through the sample, and the microstructure of the specimens was mapped by translating the sample along two orthogonal axes perpendicular to the beam by increments of 10 μm. The beam diameter was considerably smaller than the average grain size in the virgin material. Both the degree of substructure formation and the nature of the distributed microstructure were quantified from the resulting Laue diffraction patterns. The polychromatic diffraction patterns of the polycrystalline samples consisted of well-defined streaks, and the azimuthal angular width of the streaks increased with plastic strain in a manner consistent with the scaling of the misorientation distribution of high angle boundaries for sub-grains reported recently using electron microscopy techniques limited to thin foils or thin surface layers. A lattice spin correction is introduced based on this scaling law in a simple extended Taylor scheme of polycrystal plasticity to achieve a retardation of texture development that is consistent with experimental results.
Fuzzy Sky-Ground Hook Control of a Tracked Vehicle Featuring Semi-Active Electrorheological Suspension Units
Authors: Choi Seung-Bok , Park Dong-Won , Suh Moon-Suk
Published: July 2002

This paper presents vibration control of a tracked vehicle installed with electro-rheological suspension units (ERSU). As a first step, a double-rod type ERSU is designed on the basis of the Bingham model of commercially available ER fluid, and its spring and damping characteristics are evaluated with respect to the intensity of electric fields. Subsequently, a 16 degree-of-freedom model for a tracked vehicle featuring the ERSU is established followed by the formulation of a new sky-ground hook controller. This controller takes account for both ride quality and steering stability by adopting a weighting parameter between two performance requirements. The parameter is appropriately determined by employing a fuzzy algorithm associated with two fuzzy variables: the vertical speed of the body and the rotational angular speed of the wheel. Control performances to isolate the vibration from bump and random road excitations are evaluated through computer simulations.
A New Method for Correcting Shadow Band Diffuse Irradiance Data
Authors: Muneer T. , Zhang X.
Published: July 2002

An instrument commonly used to measure diffuse irradiance is the polar-axis shadow band pyranometer. However, the shadow band that is used to prevent the beam energy from entering the pyranometer also obscures part of sky-diffuse irradiance. A correction factor must hence be applied to obtain as accurate as possible the estimation of the true diffuse irradiance. In this article, the development of a new model based on an anisotropic sky-diffuse distribution theory is presented. The proposed model is validated using two databases from different sites with various sky conditions. Drummond’s method, which is based on geometrical calculation, is also examined using the same databases. Comparison of the results obtained through application of the proposed model, with those generated by Drummond’s method shows that, for the case of Bracknell, UK the proposed method gives a root mean square error (RMSE) of 12 W/m2, as compared to Drummond’s figure of 16 W/m2. For the case of Beer Sheva, Israel the proposed model produces an RMSE of 17 W/m2, while Drummond’s procedure results in 23 W/m2. It has been demonstrated herein that the proposed method is not site specific.
Sealing Performance of New Gasketless Flange
Authors: Noda Nao-Aki , Nagawa Masato , Shiraishi Fumitaka , Inoue Akifumi
Published: July 2002

This paper deals with a new seal system between two flanges without using gaskets. The system includes a groove and an annular lip that is held by one of the flange with its highest point in contact with the other flange to form a seal line when the flanges are assembled. The condition whether the system leaks or not depends on the shape and dimension of the annular lip and its deformation during the contact. In this study, several gasketless flanges are prepared with different lip dimensions to investigate the contact and sealing condition through an experimental and FEM analyses. The analyses indicate that the conditions can be expressed in terms of the maximum contact stress and the plastic zone size when the flanges are assembled. The helium leak testing reveals that the gasketless flange has better sealing performance compared to conventional gaskets.
Fractal Estimation of Flank Wear in Turning
Authors: Bukkapatnam Satish T. S. , Kumara Soundar R. T. , Lakhtakia Akhlesh
Published: July 2002

A novel fractal estimation methodology, that uses—for the first time in metal cutting literature—fractal properties of machining dynamics for online estimation of cutting tool flank wear, is presented. The fractal dimensions of the attractor of machining dynamics are extracted from a collection of sensor signals using a suite of signal processing methods comprising wavelet representation and signal separation, and are related to the instantaneous flank wear using a recurrent neural network. The performance of the resulting estimator, evaluated using actual experimental data, establishes our methodology to be viable for online flank wear estimation. This methodology is adequately generic for sensor-based prediction of gradual damage in mechanical systems, specifically manufacturing processes. [S0022-0434(00)02401-1]
Low-Cycle Fatigue of TiNi Shape Memory Alloy and Formulation of Fatigue Life
Authors: Tobushi Hisaaki , Nakahara Takafumi , Shimeno Yoshirou , Hashimoto Takahiro
Published: July 2002

The low-cycle fatigue of a TiNi shape memory alloy was investigated by the rotating-bending fatigue tests in air, in water and in silicone oil. (1) The influence of corrosion fatigue in water does not appear in the region of low-cycle fatigue. (2) The temperature rise measured through an infrared thermograph during the fatigue test in air is four times as large as that measured through a thermocouple. (3) The fatigue life at an elevated temperature in air coincides with the fatigue life at the same elevated temperature in water. (4) The shape memory processing temperature does not affect the fatigue life. (5) The fatigue equation is proposed to describe the fatigue life depending on strain amplitude, temperature and frequency. The fatigue life is estimated well by the proposed equation. [S0094-4289(00)01102-6]
Fluid Dynamics and Transport of Droplets and Sprays
Authors: Sirignano, William A. , Tryggvason, Gretar
Published: July 2002

[S0098-2202(00)03101-1]
Effect of Two-Scale Roughness on Boundary Layer Transition Over a Heated Flat Plate: Part 1—Surface Heat Transfer
Authors: Pinson Mark W. , Wang Ting
Published: July 2002

An experimental study was conducted to investigate surface heat transfer and boundary layer development associated with flow over a flat test surface covered with two roughness scales. Two-scale roughness was used because in-service aeroengines commonly display larger roughness concentrated at the leading edge with smaller roughness distributed downstream. The first scale, covering up to the first 5 cm of the test surface, was in the form of a sandpaper strip, an aluminum strip, or a cylinder. The second roughness scale covered the remainder of the test surface (2 m) in the form of sandpaper or a smooth surface. In Part 1, the surface heat transfer results are examined. Even though the roughness scales were hydraulically smooth, they induced significantly earlier transition onset, with the two-dimensional roughness causing earlier transition than three-dimensional roughness. All of the rough/smooth cases unexpectedly triggered earlier transition than rough/rough cases. This indicated that the scale of the step-change at the joint between two roughness scales was predominant over the downstream roughness on inducing early transition. Reducing the overall height of the step change was shown to have a greater effect on transition than the specific geometry of the roughness scale. [S0889-504X(00)00701-7]