bluuebunny/crossref_metadata_2025 huggingface dataset:
ORIGINAL ARTICLE: A Multi‐Subunit Chlamydial Vaccine Induces Antibody and Cell‐Mediated Immunity in Immunized Koalas (Phascolarctos cinereus): Comparison of Three Different Adjuvants
Authors: Carey Alison J. , Timms Peter , Rawlinson Galit , Brumm Jacqui , Nilsson Karen , Harris Jonathon M. , Beagley Kenneth W.
Published: January 2010

Citation Carey AJ, Timms P, Rawlinson G, Brumm J, Nilsson K, Harris JM, Beagley KW. A multi‐subunit chlamydial vaccine induces antibody and cell‐mediated immunity in immunized koalas (Phascolarctos cinereus): comparison of three different adjuvants. Am J Reprod Immunol 2010; 63: 161–172

Problem  Chlamydial infections represent a major threat to the survival of the koala. Infections caused by Chlamydia pecorum cause blindness, infertility, pneumonia and urinary tract infections and represent a threat to the survival of the species. Little is known about the immune response in koalas, or the safety of commonly used adjuvants for induction of protective systemic and mucosal immunity.

Method of study  In the present study, we immunized 18 healthy female koalas subcutaneously with a combination of three chlamydial antigens [major outer membrane protein (MOMP), NrdB and TC0512 (Omp85)] mixed with one of three different adjuvants [Alhydrogel, Immunostimulating Complex (ISC) and TiterMax Gold].

Results  All adjuvants induced strong neutralizing IgG responses in plasma against the three antigens with prolonged responses lasting more than 270 days seen in Alhydrogel and ISC immunized animals. Cloacal IgG responses lasting >270 days were also induced in ISC‐immunized animals. Chlamydia‐specific peripheral blood mononuclear cell proliferative responses were elicited by both Alhydrogel and ISC, and these lasted >270 days in the ISC group.

Conclusion  The data show that a multi‐subunit chlamydial vaccine, given subcutaneously, can elicit Chlamydia‐specific cell‐mediated and antibody responses in the koala demonstrating that the development of a protective vaccine is feasible.
ORIGINAL ARTICLE: Peripheral Blood NK Cells Reflect Changes in Decidual NK Cells in Women With Recurrent Miscarriages
Authors: Park Dong Wook , Lee Hyun Joo , Park Chan Woo , Hong Sung Ran , Kwak‐Kim Joanne , Yang Kwang Moon
Published: January 2010

Citation Park DW, Lee HJ, Park CW, Hong SR, Kwak‐Kim J, Yang KM. Peripheral blood NK cells reflect changes in decidual NK cells in women with recurrent miscarriages. Am J Reprod Immunol 2010; 63: 173–180

Problem  We aimed to investigate if peripheral blood natural killer (pNK) cell levels are correlated with decidual NK (dNK) cell levels, and if chemokine expression has any role in dNK cell regulation.

Method of study  Decidual tissues of women having two or more miscarriages with normal karyotype were collected after miscarriage and an immuno‐histochemisty study was made. pNK cells were evaluated using flow cytometric analysis.

Results  The %CD3−/56+ and %CD3−/56+/16+ pNK cells showed a significant correlation with mean number of CD56+ dNK cells. The number of decidual CD16+ cells was significantly higher in women with elevated pNK (≥15%) than that of normal pNK (<15%). The %CD3−/56+ and %CD3−/56+/16+ pNK cells showed an inverse correlation with duration of gestation. The CCL3+ and CXCL12+ cells were present in the decidua; however, staining intensity was not correlated with number of dNK cells.

Conclusion  The pNK cell levels reflect changes in dNK cell levels. This implicates that pNK cell level is a clinically useful marker to predict pregnancy outcome. Further study is needed to examine if elevated pNK cells enhance recruitment of dNK cells in the decidua.
Multidisciplinary approach to the treatment of an oblique crown–root fracture
Authors: Bate Anna‐Louise , Lerda Fabrizio
Published: January 2010

Abstract –  This case report describes the management of an oblique crown–root fracture of the buccal cusp of the upper right first premolar. After removal of the fractured cusp, a provisional restorative build‐up in this area was carried out, in order to carry out an endodontic treatment in a sterile environment. A glass fibre post and core were then constructed and over a 90‐day period the tooth was extruded orthodontically by 4 mm. The periodontal fibres associated with this tooth were cut with a tiny surgical blade to help to prevent reintrusion of the tooth and achieve fine contouring of the gingival margins. The new tooth position was maintained with a retainer for a further 60 days and after a period with a provisional acrylic crown, a porcelain bonded crown was fitted. This case report demonstrates that such a multidisciplinary treatment approach to an oblique subgingival fracture is a reliable and predictable manner in which to save a tooth that would have otherwise been difficult, if not impossible, to restore with a resultant good long‐term prognosis.
Histological evaluation of experimentally induced subluxation in rat molars and its implications on the management of orthodontic treatment
Authors: Pereira Alex Luiz Pozzobon , De Mendonça Marcos Rogério , Sonoda Celso Koogi , Cuoghi Osmar Aparecido , Poi Wilson Roberto
Published: January 2010

Abstract –  The purpose of this study was to evaluate the histological alterations occurred in the periradicular region of rat molars after intentional subluxation using an experimental method to induce dentoalveolar trauma. Eighteen adult male Wistar rats (Rattus norvegicus albinus) were selected for the study. The dentoalveolar trauma was experimentally induced by the application of an occlusogingival force on the occlusal surface of the maxillary right first molar using a tensiometer secured on a fully articulated support with adjustable steel shafts. The animals were assigned to six groups (n = 3), according to the intensity of the force applied to induce trauma: Group I (GI, control) – no force application; Groups II–VI (GII–GVI) – the animals were subjected to 600, 700, 800, 900 and 1000 cN force, respectively. After experimental induction of trauma, the animals were sacrificed by anesthetic overdose and the right maxillas were removed and processed for histological analysis under light microscopy. In the animals of GII, GIII and GIV, the histological alterations were similar to those described for GI. GVI (1000 cN) presented the most severe alterations, with the occurrence of buccal bone plate fracture, alveolar fracture and root fracture, which are not present in mild traumatic injuries like subluxation. The 900 cN force (GV) was capable to produce clinical and histological alterations in the gingival and periodontal tissues compatible with those observed in subluxation.
The New European Medicines Agency Guideline on the Investigation of Bioequivalence
Authors: Morais José Augusto Guimarães , Lobato Maria do Rosário
Published: January 2010

Abstract:  In this MiniReview, the main modifications made during the revision of the current Note for Guidance on the Investigation of Bioavailability and Bioequivalence are reviewed and justified. Several new features have been added to this guideline, as well as changes aimed at improving the clarity of the guidance provided. The first issue to be addressed was to limit the scope of the guideline to bioequivalence studies for immediate release dosage forms with systemic action. Therefore, the guideline refers to bioequivalence alone. Moreover, the new definition of Generic Medicinal Product has been incorporated. Clearer guidance covering more specific cases is now given on sections such as: fed/fasting conditions, use of metabolite data, enantiomers and strength to be used in the bioequivalence study. Steady‐state design is now restricted and other designs, such as parallel group design, replicate design and two‐stage design, are now incorporated in a more explicit form. New practical guidance on Highly Variable Drug Products and Narrow Therapeutic Index Drugs has been incorporated. The possibility for a biowaiver based on the Biopharmaceutics Classification System is now more explicit for Class I drugs and can be extended to Class III drugs under restricted conditions. We are aware that the initial goal of providing a very specific and clear guidance on these issues has not been entirely achieved, mainly because it is almost impossible to cover all individual cases and predict every possible situation that may arise. Demonstration of bioequivalence will still require in many instances a case by case approach.
Black Aesthetics
Authors: Taylor Paul
Published: January 2010

This article introduces the preoccupations and themes that define the study and practice of black aesthetics. It presents a provisional sketch of a field that has long been recognized in other humanities disciplines, but that is only now gaining wide notice in academic philosophy. This sketch emphasizes the aspects of the field that invite specifically philosophic scrutiny, while touching lightly on specific artworks, critical literatures and historical developments. Among the topics that receive attention are the following: race, aesthetic politics, creolization, nationalism, modernity, white supremacy and the blues.
Moral Luck and the Law
Authors: Enoch David
Published: January 2010

Is there a difference in moral blameworthiness between a murderer and an attempted murderer? Should there be a legal difference between them? These questions are particular instances of the question of moral luck and legal luck (respectively). In this paper, I survey and explain the main argumentative moves within the general philosophical discussion of moral luck. I then discuss legal luck, and the different ways in which this discussion may be related to that of moral luck.
Gender and the Religion of Ancient Egypt
Authors: Onstine Suzanne
Published: January 2010

This article will address the issue of gender within the framework of ancient Egyptian religion. Two primary areas of importance will be explored; the role of gender in the divine world, and the role of gender for the practitioners of the religion. The religion of ancient Egypt was especially concerned with aspects of gender because of their focus on fertility and spiritual rebirth, concepts which were often expressed using gendered language and visual metaphors. The second part of the article explores the ways in which women negotiated the primarily male dominated religious hierarchy. The practice of Egyptian religion was also affected because of the gender roles that men and women played in their society. The temple was not simply a religious edifice, but also had administrative aspects that women were normally excluded from. This did not mean women were excluded from meaningful participation in the cult, but rather they forged an identity based on providing music for the cult in various ways.
Organising pneumonia associated with fumaric acid ester treatment for psoriasis
Authors: Deegan Alexander Paul , Kirby Brian , Rogers Sarah , Crotty Tom Bernard , McDonnell Timonthy John
Published: January 2010

Introduction:  We present the case of a 49‐year old male who presented with dyspnoea, cough, weight loss, night sweats and general malaise. He had been on treatment with oral fumaric acid esters (FAE, Fumaderm®; Biogen Idec GmbH, Ismaning, Germany) for 6 months.

Methods:  Report of a case.

Results:  His chest X‐ray showed patchy infiltrates in the left upper lobe which failed to resolve under empiric antibiotic therapy. A computed tomography of thorax revealed bilateral, mostly peripheral foci of consolidation with air bronchograms. Transbronchial biopsies showed a pattern of organising pneumonia (OP).

Conclusions:  Therapy with oral prednisolone (40 mg/day) resulted in a rapid clinical and radiological improvement. An association of FAE and OP has not previously been reported.

Please cite this paper as: Deegan AP, Kirby B, Rogers S, Crotty TB and McDonnell TJ. Organising pneumonia associated with fumaric acid ester treatment for psoriasis. The Clinical Respiratory Journal 2010; 4: 248–251.
Methods for Modelling Flanged and Curvic Couplings for Dynamic Analysis of Complex Rotor Constructions
Authors: Bannister R. H.
Published: January 2010

Design charts are presented whereby the practicing design engineer can determine the equivalent flexural stiffness of flanged or curvic (toothed) couplings. Results are obtained by computing the centre line slope generated by an applied couple using a Program for Automatic Finite Element Calculations (PAFEC 75). Graphical data is provided allowing the equivalent second moment of area to be determined for flanged couplings or stress contour lines describing the effective load carrying material for curvic coupled disc assemblies.
A New Rapid-Response Hydraulic Actuator—Design, Analysis and Test Results
Authors: Barkan P. , Imam I. , Premerlani W.
Published: January 2010

This paper describes the development of a new hydraulic operator with rapid response (< 0.003 seconds) and high operating velocity (10 m/sec.) to be used in a high voltage DC circuit breaker [1]–[6] now under development [8]. A new “two-way” valve employs the eddy current repulsion principle for actuation and opens to 8 cm2 flow area within 0.0005 sec. By a novel exploitation of hydraulic fluid inertia, it has proven possible to achieve with only a single, directly-actuated “two-way” valve, plus a latch, the functions which normally require a pilot-operated “three-way” valve or two “two-way” valves. These features have led to a significant simplification, reduced response time and improved reliability of the hydraulic operator and the system it operates. The paper covers unique features of the hardware design, the analysis and the test results. On the basis of theory and test, the principle sources of time delay in the hydraulic system are identified and analyzed, leading to general design principles. Both closed form and numerical analytical solutions have been developed which are in excellent agreement with experiment. A systematic evaluation has been made of the relative merits of initiating motion by increasing the pressure above a piston as contrasted to decreasing the pressure below a piston in order to achieve the fastest response. Tests run over a wide range of ambient conditions and at hydraulic pressures up to 340 atm confirm the ability of the system to move masses of the order of 10 kg a distance of 2 cm with total response time approaching 2.5 milliseconds.
Dynamic Reduction in Rotor Dynamics by the Finite Element Method
Authors: Rouch K. E. , Kao J. S.
Published: January 2010

The use of dynamic reduction of finite element matrices in rotor dynamics analysis is shown to offer advantages of computational efficiency and modeling accuracy. Solution procedures and sample results for comprehensive rotor dynamics program for design purposes are presented. The basic reduction approaches have been extensively used in general structural analysis. Application to rotor dynamics requires an extension to account for skew-symmetric gyroscopic matrices. Dynamic reduction allows the analyst to discretize the rotor to a convenient level of detail, and then retain only enough degrees of freedom to adequately describe rotor behavior. Subsequent assembly of reduced shaft matrices with bearing matrices at a given speed allows various types of analysis to be conducted including: critical speed, damped eigenvalue-eigenvector, synchronous response, and transient solution. The computer solution time is significantly reduced because of the reduced number of degrees of freedom, with little sacrifice in accuracy for the lower modes of usual interest. The repeated use of reduced rotor matrices throughout a speed range also provides reduced computer costs.
Marine Condenser Design Using Numerical Optimization
Authors: Johnson C. M. , Vanderplaats G. N. , Marto P. J.
Published: January 2010

Computer codes for the analysis of marine steam condensers were coupled with a numerical optimization code to provide fully automated design. The resulting programs are excellent design tools for the conceptual design of a condenser to meet specified constraints. Examples illustrate the versatility of this method.
Optimum Design of Air-Conditioned Buildings
Authors: Gupta B. D. , Rao S. S.
Published: January 2010

The main consideration in the design of thermally insulated buildings, apart from the energy required for operation, is the total (initial plus operating) cost. There is no simple explicit relation between the total cost and energy required to maintain the desired inside conditions which are dependent on the uncontrollable outside conditions. With limited energy resources, it is necessary to conserve energy or use it optimally. A unified approach to find the optimal combination of initial cost and operating cost (energy) or total energy requirements (cooling plus heating) for air-conditioned buildings is presented in this paper. Since the thickness of insulation is one of the important factors to be considered in reducing the external load, the optimum values of insulation thickness for walls and roof are found by using the interior penalty function method of minimization. For the computation of heat gain through external walls and roof, a design day based on the average maximum solar-air temperature (computed from the hourly meteorological data) is chosen. The sensitivity of optimum design with respect to design parameters is also found.
An Electronic Ski Binding Design with Biofeedback
Authors: Lieu D. K. , Mote C. D.
Published: January 2010

A ski release binding releases the ski boot from the ski for loading environments potentially injurious to the lower extremity. The concept of using a model reference adaptive control system to control ski binding release is explored. Model reference oscillators simulate torsion about the longitudinal leg axis and anterior-posterior bending of the lower extremity. The model oscillator coefficients are adjusted depending upon processed EMG signal levels from lower extremity muscle groups, which serve as state estimators. Background on release binding design, binding circuit diagrams and the results of preliminary tests on a binding are presented in this paper.
Effect of Geometry and Operating Conditions on Spur Gear System Power Loss
Authors: Anderson N. E. , Loewenthal S. H.
Published: January 2010

The results of an analysis of the effects of spur gear size, pitch, width and ratio on total mesh power loss for a wide range of speeds, torques and oil viscosities are presented. The analysis uses simple algebraic expressions to determine gear sliding, rolling and windage losses and also incorporates an approximate ball bearing power loss expression. The analysis shows good agreement with published data. Large diameter and fine-pitched gears had higher peak efficiencies but lower part-load efficiency. Gear efficiencies were generally greater than 98 percent except at very low torque levels. Tare (no-load) losses are generally a significant percentage of the full-load loss except at low speeds.
The Efficiency of Involute Spur Gears
Authors: Martin K. F.
Published: January 2010

Approximate equations produced by Trachman |15| are used to predict the coefficient of sliding friction between the gear teeth. These equations apply when the lubrication regime is elastohydrodynamic; this is true during many gear contacts. The equations, which require only certain basic characteristics of the lubricant and the gears, are relatively simple and produce values for the coefficient of friction which are acceptable. The use of this coefficient of friction, together with a calculation for the rolling friction force allows the calculation of instantaneous and overall efficiency of the gear train. Contact ratios greater than one are accounted for and the load is assumed to be shared equally between the pairs of teeth. The computed values show that the load torque has a significant effect on both coefficient of friction and efficiency; as the load increases the coefficient of friction increases and the efficiency decreases. The effect of speed does not, over the small range of computations made, have as much significance as load, although it appears that efficiency will probably increase as the speed increases. Comparison of these predicted results with the few experimental tests which are relevant indicates some support, especially for the load effect.
Effects of Hunting Gear Ratio Upon Surface Durability of Gear Teeth
Authors: Ishibashi A. , Tanaka S.
Published: January 2010

It was clearly shown that the pitting limits of gear pairs with a hunting gear ratio were appreciably lower than those of gear pairs with a unity gear ratio. This was ascribed to the difference in effectiveness of running-in between the mating tooth surfaces. Test gears with hardnesses ranging from 185 HB to 850 Hv were finished by hobbing, skiving or grinding. The contact fatigue damage was estimated from work-hardening at the tooth surfaces. The critical plastic strain which might cause pitting cracks was shown in terms of Brinell hardness. The availability of face-width was calculated from the two different pitting limits for gear pairs with two different gear ratios. It ranged from 0.23 to 0.80 in the present experiments because pitting limits of gear pairs with a unity gear ratio were appreciably greater. This suggested that there was a strong possibility to increase the load carrying capacity of tooth surfaces of gear pairs having gear ratios other than unity.
Minimum Energy-Loss Control of Electro- and Hydro-Mechanical Modulated Convertor Drives
Authors: Karnopp D.
Published: January 2010

Most servomechanism drives optimized for speed of response are incapable of returning any of the energy stored in a reactive load to the source. Even transmissions incorporating dynamic braking are often not fully optimized with respect to energy recovery. In this paper, drives based on modulated convertors such as separately excited d.c. motors and variable-displacement hydraulic motors are studied to discover optimum control strategies for operation in all four quadrants of the torque-speed plane, i.e., for power supply and recovery. Quite different results are found for the two nominally analogous types of converters. Although several types of energy loss are not considered in the simplified mathematical models used, the effects of electrical armature resistance and hydraulic line pressure loss together with constant voltage and constant pressure accumulators indicate basically different optimum control strategies. For the types of systems studied, it is found that gyrotors such as electric motors have good efficiency for sustained high speeds while transformer systems such as hydraulic motors are relatively more efficient for transient operation near zero speed. Naturally, the absolute efficiency of a practical drive system depends on a number of additional factors not considered here.
Some Notes on V-Belt Drives
Authors: Gerbert B. G.
Published: January 2010

This paper consists of four separate parts: 1) Radial penetration of a V-belt, 2) Formulas for axial forces, 3) Additional slip in varispeed drives, 4) Arc of contact in belt drives. There is a slight connection between the parts in the way that all the results are applicable to variable speed drives. 1 The penetration of a V-belt into the groove depends on wedge angle, friction, elasticity of the belt and belt design. It is shown that certain combinations of these parameters result in zero penetration i.e., there is a kind of blocking. This is different from the well known self-locking phenomenon, where the belt is prevented to move outwards if the wedge angle is less than the friction angle. 2 The axial forces calculated from the theory of V-belt mechanics are not possible to express in simple formulas. However, approximate formulas can be developed. Previously reported formulas are here completed with the influence of belt design and elastic properties of the belt. It is convenient to use formulas in the computerized analysis of variable speed drives. 3 In variable speed drives consisting of e.g. one spring loaded pulley and one rigid (manually adjustable) pulley there are two kinds of speed loss present. Except the ordinary slip between the belt and the pulleys there is an additional speed loss due to a small axial motion of the spring loaded pulley. The additional speed loss depends on spring load, transmitted torque, drive geometry, friction, elastic properties of the belt and, what is important, the flexural rigidity of the belt. On a spring loaded driver pulley the width between the pulley halves always increases with increasing torques whereas the width of a spring loaded driven pulley can both increase and decrease. This means that in the first case the additional speed loss is always positive but in the second case it can be both positive and negative. If the maximum slip is used as a design criterion it is important to recognize this difference. 4 The arc of contact is included in the formulas presented in part 2. The geometric arc of contact differs from the real one due to the curvature of the belt between the pulleys. Previously ordinary beam theory has been applied to calculate the decrease in contact angle. Here a modified analysis is presented—except flexural rigidity also compressibility of the belt is introduced. It appears that the decrease in contact angle in ordinary belt drives is considerably smaller than that predicted by the beam theory. Sometimes the contact angle can increase. In most cases the change in contact angle is negligible and the geometric arc of contact can be used in the formulas in part 2.
An Extended Model for Determining Dynamic Loads in Spur Gearing
Authors: Kasuba R. , Evans J. W.
Published: January 2010

In this study a large scale digitized approach is used for an uninterrupted static and dynamic analysis of spur gearing. An interactive method was developed to calculate directly the variable gear mesh stiffness as a function of transmitted load, gear profile errors, gear tooth deflections and gear hub torsional deformation, and position of contacting profile points. The developed methods are applicable to both the normal and high contact ratio gearing. Certain types of simulated sinusoidal profile errors and pitting can cause interruptions of the normal gear mesh stiffness function and, thus, increase the dynamic loads in gearing.
Effect of Asperity Interaction on Pitting in Rollers and Gears
Authors: Ichimaru K. , Nakajima A. , Hirano F.
Published: January 2010

Influences of following factors upon the severity of asperity contacts and the life-to-pitting were investigated using rolling/sliding contact of two rollers; (1) the nature of drive, i.e., drive ratio of 1:1, one of 29:28 and friction drive, (2) characteristics of surface topography, (3) slide/sweep ratio. As results, combined effects of these factors were found and the conclusive remarks were consistent with the results of gear tests which were carried out using gear ratios 1:1 and 27:25. The authors discuss the mechanism of pitting from the point of view of the asperity interaction.
Instantaneous Kinematics of Multiple-Degree-of-Freedom Motions
Authors: Nayak J. H. , Roth B.
Published: January 2010

This paper treats the first-order kinematic properties of three dimensional motions with any number of freedoms from one to five. A method is presented for obtaining the canonical coordinates, the instantaneous invariants, the loci of the instantaneous screws, the canonic form of the equation of motion and its series expansion. Using this method we obtain entirely new results for three, four and five-degree-of-freedom motions, and verify some known results for one, two and three-degree-of-freedom motions.
Optimization of High Speed Geneva Mechanisms
Authors: Lee T. W.
Published: January 2010

This paper presents an analytical and computer-aided procedure on the optimum design of Geneva mechanism. The subject is treated in two parts. In Part I, a set of parameters is derived for evaluating the performance and determining the dimensions of Geneva mechanism suitable for high-speed operation. The effects of geometry on dynamics, stress, as well as kinematics of the Geneva mechanism are investigated. Classical mechanics theory is used to derive explicit relationships between these performance parameters and the design parameters. Unlike conventional design, the dynamic load rather than the static load is used for the design for high speed. Computer-aided evaluations as well as the analytical results show that the dynamic load depends strongly on the geometrical parameters and is significant at high speeds and high inertial loading. It cannot, therefore, be overlooked. In general, the dynamic load imposes an upper bound on the determination of the width of a Geneva wheel. Based on the analysis presented in Part I, a unit computer program for the design of high-speed Geneva mechanism is described in Part II. The effects of the design parameters on Geneva performance are then investigated and design guidelines are presented. Using this procedure, the “computer-design model” is demonstrated, in examples, to be capable of running at higher speeds with a longer life than the models designed through conventional techniques.
Determination of Extreme Distances of a Robot Hand—Part 1: A General Theory
Authors: Sugimoto K. , Duffy J.
Published: January 2010

In this paper the following two theorems are proved; 1) All intermediate joint axes of a robot arm with arbitrary number of joints intersect an extreme distance line between an arbitrary base point and the center point of the hand (extreme reach), and 2) all intermediate joint axes intersect an extreme perpendicular distance line from the center point of the hand to any arbitrary line in space. (The theorem for extreme mutual perpendicular distance lines has already been proved by Shimano and Roth [1, 2]). Using the first theorem an algorithm is developed for searching for extreme reaches. This algorithm can be applied with minor modifications to determine both extreme perpendicular lines and extreme mutual perpendicular lines. The algorithm can fail when applied to robot arms with special dimensions (for instance, robot arms with intersecting or parallel axes). Such cases are studied in detail in a second paper [3].
On the Principle of Transference In Three-Dimensional Kinematics
Authors: Hsia L. M. , Yang A. T.
Published: January 2010

In this paper, the principle of transference is developed and applied to the establishment of a systematic procedure for the determination, via screw calculus, of a prescribed rigid body motion. This is an essential first step toward the study of the intrinsic properties of point trajectories in three-dimensional kinematics. Two numerical examples are presented for illustrative purposes.
A Classification of Coupler-Line Envelopes from Hinged Four-Bar Linkages
Authors: Kimbrell J. E. , Hunt K. H.
Published: January 2010

The loci of straight lines (attached to moving links in mechanisms) call for further study, because translation along a line can be identified with the movement at a sliding pair. The paths of points (identifiable with turning pairs) have been examined in considerable depth, almost to the exclusion of loci of lines. A line fixed on the coupler of a four-bar linkage generates an envelope, the line-counterpart of the well-known coupler-point curve. Such envelopes are here classified into 27 patterns, with the objects of both providing a broad geometrical base for further study and assisting towards practical applications in mechanism design. The classification is, in the main, limited to those linkages displaying greatest generality, but means of extending the classification are mentioned.
Fatigue Damage of the Locomotive Suspension Elements Under Random Loading
Authors: Garivaltis D. S. , Garg V. K. , D’Souza A. F.
Published: January 2010

Spectral analysis techniques are employed to analyze the fatigue damage to the suspension of a six-axle locomotive on tangent track with vertical and lateral random track irregularities. The locomotive is represented by a thirty-nine (39) degrees of freedom linear model. Spectral densities of forces and probability density functions for stress levels in suspension elements are generated. Using a modified definition of transmissibility, the probability density functions of the output/input and mean square values of outputs are obtained for various stiffness ratios. A cumulative linear damage criterion based on Miner’s theory is employed to predict fractional damage per operational second and mean life of the suspension elements. Operational stress cycles/sec. versus operational stress level are plotted for the suspension elements. These operational characteristics in conjunction with fatigue characteristics (S-N curve) can be effectively used as a tool for fatigue design.
Design of Aluminum Bicycle Frames
Authors: Davis R. , Hull M. L.
Published: January 2010

This paper presents the use of a hybrid stress analysis method for the prediction of fatigue life of bicycle frames. A finite beam element computer program is used to calculate frame stresses. In order to correlate the results with actual frame stresses, brittle coating experiments are conducted on an aluminum frame. Strain gage experiments, guided by the brittle coating results, provide more accurate measurements of maximum principal stresses. Stress concentration factors are defined, the fatigue life of an aluminum frame is predicted for a simple loading condition, and the result is compared with in-service failure data.
Kinematic Correction for Roller Skewing
Authors: Savage M. , Loewenthal S. H.
Published: January 2010

A theory of kinematic stabilization of rolling cylinders is developed for high-speed cylindrical roller bearings. This stabilization requires race and roller crowning to produce changes in the rolling geometry as the roller shifts axially. These changes put a reverse skew in the rolling elements by changing the rolling taper. Twelve basic possible bearing modifications are identified in this paper. Four have single transverse convex curvature in the rollers while eight have rollers with compound transverse curvature composed of a central cylindrical band of constant radius surrounded by symmetric bands with both slope and transverse curvature.
New Complex-Number Forms of the Euler-Savary Equation in a Computer-Oriented Treatment of Planar Path-Curvature Theory for Higher-Pair Rolling Contact
Authors: Sandor G. N. , Erdman A. G. , Hunt L. , Raghavacharyulu E.
Published: January 2010

It is well known from the theory of Kinematic Synthesis of planar mechanisms that the Euler-Savary Equation (ESE) gives the radius of curvature and the center of curvature of the path traced by a point in a planar rolling-contact mechanism. It can also be applied in planar linkages for which equivalent roll-curve mechanisms can be found. Typical example: the curvature of the coupler curve of a four-bar mechanism. Early works in the synthesis of mechanisms concerned themselves with deriving the ESE by means of combined graphical and algebraic techniques, using certain sign conventions. These sign conventions often become sources of error. In this paper new complex-number forms of the Euler-Savary Equation are derived and are presented in a computer-oriented format. The results are useful in the application of path-curvature theory to higher-pair rolling contact mechanisms, such as cams, gears, etc., as well as linkages, once the key parameters of an equivalent rolling-contact mechanism are known. The complex-number technique has the advantage of eliminating the need for the traditional sign conventions and is suitable for digital computation. An example is presented to illustrate this.
Generalized Coordinate Partitioning for Dimension Reduction in Analysis of Constrained Dynamic Systems
Authors: Wehage R. A. , Haug E. J.
Published: January 2010

This paper presents a computer-based method for formulation and efficient solution of nonlinear, constrained differential equations of motion for mechanical systems. Nonlinear holonomic constraint equations and differential equations of motion are written in terms of a maximal set of Cartesian generalized coordinates, to facilitate the general formulation of constraints and forcing functions. A Gaussian elimination algorithm with full pivoting decomposes the constraint Jacobian matrix, identifies dependent variables, and constructs an influence coefficient matix relating variations in dependent and independent variables. This information is employed to numerically construct a reduced system of differential equations of motion whose solution yields the total system dynamic response. A numerical integration algorithm with positive-error control, employing a predictor-corrector algorithm with variable order and step size, is developed that integrates for only the independent variables, yet effectively determines dependent variables. Numerical results are presented for planar motion of two tracked vehicular systems with 13 and 24 degrees of freedom. Computational efficiency of the algorithm is shown to be an order of magnitude better than previously employed algorithms.
Instantaneous Properties of Trajectories Generated by Planar, Spherical, and Spatial Rigid Body Motions
Authors: McCarthy J. M. , Roth B.
Published: January 2010

This paper develops relationships between the instantaneous invariants of a motion and the local shape of the trajectories generated during the motion. We consider the point trajectories generated by planar and spherical motions and the line trajectories generated by spatial motion. Those points or lines which generate special trajectories are located on (and define) so-called boundary loci in the moving body. These boundary loci define regions, within the body, for which all the points or lines generate similarly shaped trajectories. The shapes of these boundaries depend directly upon the invariants of the motion. It is shown how to qualitatively determine the fundamental trajectory shapes, analyze the effect of the invariants on the boundary loci, and how to combine these results to visualize the motion trajectories to the third order.
Bending Performance of Fiber-Optic Cable Sheaths: Application of New Apparatus and Techniques
Authors: Santana M. R. , Yanizeski G. M.
Published: January 2010

Apparatus and techniques were developed by which moment-curvature curves can be generated over a wide range of curvatures, cable diameters, and environmental conditions. The resulting curves can be used to analyze bending performance in the same way as stress-strain curves are used to analyze tensile performance. In the first series of tests using this apparatus, five wire-reinforced fiber-optic cable sheaths were tested at room temperature. The wire reinforcement had a dominant, theoretically predictable effect on the bending stiffness of certain designs, while it was relatively unimportant in others. The key difference is the degree of encapsulation of the reinforcement, which can be controlled by simple changes in design. In addition, buckling performance can be improved by increasing the cross-sectional rigidity. In both cases, tensile performance is relatively unaffected. These findings are exemplified by the performances of a single-ply and a crossply design. Compared to the single ply, the crossply has the more rigid cross section and the lower degree of encapsulation. Both sheaths have nearly equal bending stiffness throughout the entire range of curvature, and the buckling radius of the crossply design (7.4 cm) is better than that of the single-ply design (8.4 cm) despite a 2 to 1 advantage in tensile stiffness. An effective design sequence has evolved from the results of this study: (a) select reinforcement for tensile performance, (b) adjust cross-sectional rigidity for buckling performance, and (c) adjust reinforcement encapsulation for bending stiffness performance. In this sequence, each step is nearly independent of the others.
Maximum Stiffness Design for Elastic Bodies in Contact
Authors: Benedict R. L.
Published: January 2010

An optimality criteria approach for the stiffness design problem is developed for the case of two elastic bodies in frictionless contact. The contact problem is analyzed by appending the nonpenetration constraint to the system potential energy. Necessary and sufficient conditions for stiffness maximization are derived. A computational method for design problem solution is developed and numerical results for a beam on a foundation are displayed.
Fail-Safe Optimal Design of Complex Structures With Substructures
Authors: Nguyen D. T. , Arora J. S.
Published: January 2010

In this paper, the problem of fail-safe design of complex structural systems is considered. A substructural formulation for this class of design problems is presented. Constraints are imposed on stresses, deflections, natural frequency, and member sizes. It is shown that a structure can be designed to withstand the projected future damage. It is also shown that the substructural formulation offers computational advantage for both structural analysis and design sensitivity analysis parts of an optimal design algorithm. Fail-safe designs of open truss and closed helicopter tailbooms are obtained using a program developed based on the substructural formulation.
On the Drive Systems for High-Performance Machines
Authors: Pasch K. A. , Seering W. P.
Published: January 2010

The choice of actuators and transmissions in high performance machines and manipulators can have a profound effect on the time required for a specified machine task. For systems operating with mechanical constraints, such as limits on allowable angular velocities in motors, designing for greatest achievable acceleration will not always minimize move time. In this paper the effects on performance of ranges of choices of actuators and transmission mechanisms are evaluated, and guidelines for choosing the optimal drive elements are presented.
Multiple Design Objectives in Hydrodynamic Journal Bearing Optimization
Authors: Metwalli S. M. , Shawki G. S. A. , Mokhtar M. O. A. , Seif M. A. A.
Published: January 2010

A novel approach is presented to optimize the finite journal bearing performance under steady loading conditions. Closed form expressions representing the behavior of the bearing as explicit functions of the design variables are utilized. Different competing objectives are assumed to suit various design applications. A method of multiplying objectives and raising to different exponents has been adopted. The basic competing objectives are minimum power loss, maximum-minimum film thickness, minimum side leakage, minimum temperature rise, and minimum bearing size. A journal bearing design procedure for optimum performance is thus devised for the selection of optimum bearing length, clearance, and oil viscosity. A numerical example is also presented.
Monotonicity Analysis and the Reduced Gradient Method in Constrained Optimization
Authors: Zhou J. , Mayne R. W.
Published: January 2010

The concept of monotonicity analysis is combined with the reduced gradient technique for design optimization. The combination is based on a strategy for applying monotonicity analysis in specified search directions and incorporates this strategy into an iterative procedure for identifying the active inequality constraints in an optimization problem. As the active constraints are identified, the reduced gradient information based on these constraints forms the basis for a variable metric search leading to the constrained optimum. Test results are presented which indicate the performance of two different algorithms using this approach.
An Algorithm for Automatic Sketching of Planar Kinematic Chains
Authors: Olson D. G. , Thompson T. R. , Riley D. R. , Erdman A. G.
Published: January 2010

One of the problems encountered in attempting to computerize type synthesis of mechanisms is that of automatically generating a computer graphics display of candidate kinematic chains or mechanisms. This paper presents the development of a computer algorithm for automatic sketching of kinematic chains as part of the computer-aided type synthesis process. Utilizing concepts from graph theory, it can be shown that a sketch of a kinematic chain can be obtained from its graph representation by simply transforming the graph into its line graph, and then sketching the line graph. The fundamentals of graph theory as they relate to the study of mechanisms are reviewed. Some new observations are made relating to graphs and their corresponding line graphs, and a novel procedure for transforming the graph into its line graph is presented. This is the basis of a sketching algorithm which is illustrated by computer-generated examples.
Inertia Effects of a Roller-Chain on Impact Intensity
Authors: Chew M.
Published: January 2010

The magnitudes of the impacts in chain drives are a function of the sprocket speed, chain link pitch, the number of links in the chain span, and the mass distribution within each link. The impulsive force may be viewed as equivalent to the effective mass of the chain span being concentrated at the roller and applied to the sprocket at the impact velocity. This effective mass is derived in this paper from first principles using Lagrange’s impact equations. Contrary to accepted rules, it was found that the effective mass decreases with increase in chain length. Moreover the impulsive force on the links of the chain span decreases exponentially with the distance from the impacted roller. Motion characteristics of the chain immediately after impact are also discussed.
Lubricant Jet Flow Phenomena in Spur and Helical Gears With Modified Center Distances and/or Addendums—For Out-of-Mesh Conditions
Authors: Akin L. S. , Townsend D. P.
Published: January 2010

The work reported is an extension from a previous study which was limited to standard centers and tooth proportions only. This paper includes long and short addendums and modified center distances. The analysis develops the equations for the limit values of variables necessary to remove prior severe limitations or constraints necessary to facilitate computer analysis. A new computer program IMPOUT2 has been developed using these newly established “Limit Formulas” to prevent negative impingement on the pinion. The industrial standard nozzle orientation usually found where the offset S = 0 and inclination angle β = 0 will often cause the pinion to be deprived of primary impingement which can be an important cause of incipient scoring failure in high-speed drives.
On Dynamic Tooth Load and Stability of a Spur-Gear System Using the State-Space Approach
Authors: Kumar A. S. , Sankar T. S. , Osman M. O. M.
Published: January 2010

In this study, a new approach using the state-space method is presented for the dynamic load analysis of spur gear systems. This approach gives the dynamic load on gear tooth in mesh as well as information on the stability of the gear system. Also a procedure is given for the selection of proper initial conditions that enable the steady-state condition to be reached faster, conditions that result in considerable savings in computational time. The variations in the dynamic load with respect to changes in contact position, operating speed, backlash, damping, and stiffness are also investigated. In addition, the stability of the gear system is studied, using the Floquet theory and the well-known stability conditions of difference systems.
Application of Singular Value Decomposition for Analysis of Mechanical System Dynamics
Authors: Mani N. K. , Haug E. J. , Atkinson K. E.
Published: January 2010

A singular value decomposition method for efficient solution of mixed differential-algebraic equations of motion of mechanical systems is developed. Differential equations of motion are written in terms of a maximal set of Cartesian generalized coordinates that are related through nonlinear algebraic constraint equations. Singular value decomposition of the constraint Jacobian matrix is used to define a new set of generalized coordinates that are partitioned into optimal independent and dependent sets. Integration of only independent generalized coordinates generates all system information. A numerical example is presented to demonstrate effectiveness of the method.