bluuebunny/crossref_metadata_2025 huggingface dataset:
Compliant layer bearings in artificial joints. Part 2: Simulator and fatigue testing to assess the durability of the interface between an elastomeric layer and a rigid substrate
Authors: Jones E , Scholes S C , Burgess I C , Ash H E , Unsworth A
Published: December 2008

Artificial joints have been much improved since their introduction but they still have a limited lifetime. In an attempt to increase their life by improving the lubrication acting within these prostheses, compliant layered polyurethane (PU) joints have been devised. These joints mimic the natural synovial joint more closely by promoting fluid film lubrication. In this study, tests were performed on compliant layer joints to determine their ability to function under a range of conditions. Both static and dynamic compression tests were undertaken on compliant artificial hip joints of two different radial clearances. Friction tests were also performed before and after static loading. In addition to this, knee wear tests were conducted to determine the suitability of a compliant layer in these applications. In the knee tests, variations in experimental testing conditions were investigated using both active and passive rotation and severe malalignment of the tibial inserts. The static compression tests together with the friction studies suggest that a small radial clearance is likely to result in ‘grabbing’ contact between the head and cup. The larger radial clearance (0.33 μm) did not exhibit these problems. The importance of the design of the compliant layer joints was highlighted with delamination occurring on the lateral bearings during the knee wear studies. The bearings with a layer 2 mm thick performed better than the bearings with a layer 3 mm thick. Tests conducted on flat PU bearings resulted in no delamination; therefore, it was concluded that the layer separation was caused by design issues rather than by material issues. It was found that, with careful material choice, consideration of design, and effective manufacturing techniques, the compliant layer joint functioned well and demonstrated durability of the union between the hard and soft layers. These results give encouragement for the suitability of these joints for clinical use.
Currently available medical engineering degrees in the UK. Part 1: Undergraduate degrees
Authors: Joyce T
Published: December 2008

This paper reviews mechanical-engineering-based medical engineering degrees which are currently provided at undergraduate level in the UK. At present there are 14 undergraduate degree programmes in medical engineering, offered by the University of Bath, University of Birmingham, University of Bradford, Cardiff University, University of Hull, Imperial College London, University of Leeds, University of Nottingham, University of Oxford, Queen Mary University of London, University of Sheffield, University of Southampton, University of Surrey, and Swansea University. All these undergraduate courses are delivered on a full-time basis, both 3 year BEng and 4 year MEng degrees. Half of the 14 degree courses share a core first 2 years with a mechanical engineering stream. The other seven programmes include medical engineering modules earlier in their degrees. Within the courses, a very wide range of medical-engineering-related modules are offered, although more common modules include biomaterials, biomechanics, and anatomy and physiology.
Inverse-kinematics-based control of a redundantly actuated platform for rehabilitation
Authors: Saglia J A , Tsagarakis N G , Dai J S , Caldwell D G
Published: December 2008

The paper introduces the control of a redundantly actuated parallel mechanism for ankle rehabilitation which is based on online inverse kinematics calculation to generate required actuating parameters to control the mechanism and achieve the required dynamic response. The geometry of the mechanism is described and the design parameters are investigated in the analysis of singularity and dexterity. The dynamic model is developed and the tuning of the control gains is performed by analysing the level of actuation conflict and tracking error that have been minimized by varying the controller parameters. The paper further examines the actuation conflict and evaluates its association with the control parameters. Both simulation and experiments were carried out to implement the analysis and control strategy in the mechanism.
A tailored non-linear fluctuation smoothing rule for semiconductor manufacturing factory scheduling
Authors: Chen T
Published: December 2008

A tailored non-linear fluctuation smoothing rule is proposed in this study to improve the performance of scheduling jobs in a semiconductor manufacturing factory. The tailored non-linear fluctuation smoothing rule is modified from the well-known fluctuation smoothing rules with three innovative treatments. At first, the fluctuation in the remaining cycle time estimate is smoothed and then its influence is balanced with that of the release time or the mean release rate. Subsequently, the difference in the slack is magnified by applying the ‘division’ operator instead. Thirdly, the content of the non-linear fluctuation smoothing rule can be tailored to the semiconductor manufacturing factory to be scheduled. In order to evaluate the effectiveness of the proposed methodology, production simulation is also applied in this study to generate some test data. According to experimental results, the proposed methodology out-performed nine existing approaches in reducing the cycle time averages and standard deviations. In addition, the tailored non-linear scheduling rule was also shown to be a Pareto optimal solution for scheduling jobs in a semiconductor manufacturing factory.
Enhancement of the tipover stability of mobile manipulators with non-holonomic constraints using an adaptive neuro-fuzzy-based controller
Authors: Ghaffari A , Meghdari A , Naderi D , Eslami S
Published: December 2008

The stability issue of mobile manipulators, particularly when the end-effector and the vehicle have to follow a predefined trajectory (for some special duties like painting a plane or carrying a light load), is a crucial subject and needs special attention. In this paper, by utilizing the manipulator compensation motions, the instantaneous proper configuration for a redundant mobile robot is determined. A fast methodology taking into account the dynamic interaction between the manipulator and the vehicle is proposed for enhancing the tipover stability (i.e. stability against overturning) of the mobile manipulator by employing the soft computing approach including a genetic algorithm, neural network, and adaptive neuro-fuzzy inference (ANFIS) controller. A genetic algorithm is utilized to find a minimum value for a function, called the performance index here, to determine the tipover stability measure. In such an algorithm, utilizing the values attained, a neural network look-up table is planned. This look-up table will expedite the operation of tracking a specified trajectory for the end-effector while the mobile manipulator simultaneously maintains its tipover stability in the most favourable manner. The benefit of using the neural network is its capacity for online control; the genetic algorithm alone cannot provide this. In this case the performance index is minimized and the rule base (the main part of an ANFIS controller) for the adaptive neuro-fuzzy controller is designed. It is considered that the tipover stability of the mobile manipulator is increased by applying the rule base of the ANFIS controller to the system. For evaluating the effectiveness and performance of the proposed algorithm, a spatial mobile manipulator is examined.
On the rationale behind constant fuel utilization control of solid oxide fuel cells
Authors: Vijay P , Samantaray A K , Mukherjee A
Published: December 2008

The optimal energy efficient operating conditions of a solid oxide fuel cell (SOFC) system needs to be studied by considering the whole closed circuit system rather than a standalone study of the cell efficiency. This study is performed in this paper with the aid of steady state models of the SOFC, the after-burner, and the heat exchanger. For the first time, a comprehensive steady state model of the SOFC is developed and validated. A recursive algorithm with two cascaded optimization loops is applied to maximize the SOFC system efficiency and also to obtain the corresponding cell operating conditions. The developed steady state model aids in the implementation of the optimization procedure. Controlling the SOFC system for maximum efficiency operation for variable loads requires complex control laws. However, it is found that an appropriately chosen constant fuel utilization (FU) operation closely approximates the maximum efficiency operation of the fuel cell in its operating range. This is validated through closed-loop dynamic simulations of a bond graph model of the complete SOFC system. Three different commonly used control strategies and their implications on the energy and exergy efficiencies of the system, as well as their transient load following capabilities, are investigated.
Characterization of thermally sprayed micro- and nanocrystalline cylinder wall coatings by means of a cavitation test
Authors: Hahn M , Fischer A
Published: December 2008

The future development of motor engine design and technology governs the increasingly demanding requirements on materials in terms of friction and wear properties. In order to reduce emissions and achieve economical and environmentally sound solutions, thermal-spray processes became an interesting alternative to manufacture wear resistant and low-friction cylinder surfaces. Three thermal-spray processes are of major interest: twin wire arc system, high-velocity oxygen fuel and plasma transferred wire arc. The energy to heat the feedstock and the kinetic energy to accelerate the molten particles to the substrate differ within these processes consequently resulting in differing lamellar microstructures of the coatings. Hitherto, low-alloyed carbon steels with 0.1–0.8 wt% carbon have been successfully used for cylinder coatings. The motivation to alleviate friction losses is currently based on the material development of a new iron-base alloy with chromium and boron. This should solidify into a nanocrystalline or even amorphous matrix of high wear resistance. Prior to engine tests these coatings are characterized in laboratory by means of bench tests for adhesive tensile strength, tribological properties, and fatigue of the composite. Thus cavitation tests should reveal the tribological stability of these coatings and their ability to resist high-frequency cyclic impact stresses. The objective in this investigation is to describe the cavitation behaviour and the influence of voids like pores or oxides.
Instantaneous angular speed and power for the diagnosis of single-stage, double-acting reciprocating compressor
Authors: Al-Qattan M , Al-Juwayhel F , Ball A , Elhaj M , Gu F
Published: December 2008

Advance condition monitoring systems that use cylinder pressure as a primary feedback variable have been developed. Application has been limited by the cost and difficulties associated with the intrusive cylinder pressure sensor installation. Non-intrusive measurements, the instantaneous angular speed (IAS) and power, have been performed to incorporate the effect of faults in a single-stage, single-cylinder double-acting reciprocating compressor. The study simulates a hydrogen make-up compressor to define a diagnosis criterion that may be used for the condition monitoring of a reciprocating compressor. It involves the development of mathematical models for three physical conditions: excess clearance, cylinder pressure variation, and variation of valves flow area. The simulation is conducted using the torque balance, energy equation, valve dynamics, and flow through the valves. The simulation produced unique effects for each of the physical conditions. The results predicted by the model are validated with the data from the hydrogen make-up compressor located in a Kerosene Desulphurization Unit using the pressure-volume diagram (PV) analysis. This paper presents IAS and power as non-intrusive diagnosis tools. Results showing the effect of faults on the IAS and power trends are presented.
Frictional and wear performance of polyester composites based on coir fibres
Authors: Yousif B F
Published: December 2008

This article presents an evaluation of frictional and wear performance of new polyester composites based on coir fibres. Coir fibre-reinforced polyester (CFRP) composites were developed in a multi-layer form, mainly in three and four layers. The influence of the coir fibres on the wear and frictional behaviour of polyester was evaluated using a block-on-disc (BOD) machine under dry sliding contact conditions against smooth stainless steel. Worn surfaces of the composites were observed using a scanning electron microscope. The friction coefficient and specific wear rate were presented as a function of sliding distance (0-4.2 km) at different applied loads (10-30 N). The results revealed that all test parameters have a very significant influence on the frictional and wear characteristics of the materials. Moreover, a higher coefficient of friction was exhibited in the four-layer composite. CFRP composites based on three layers exhibited better wear and frictional performance compared with the one with four layers and neat polyester. The wear mechanism was predominated by deformation and micro-ploughing in the resinous regions and debonding of fibres.
Predicting the thermal behaviour of engine oils using artificial neural networks
Authors: Abou-Ziyan H Z , Mahmoud M A , Zaid Abou M A
Published: December 2008

A multi-layer neural network (NN) was developed to analyse experimental boiling data obtained for five engine oils at bulk temperatures ranging from 40 to 150 °C and heat fluxes ranging from 30 to 400 kW/m2. The inputs to the NN were the oil chemical composition (nine elements) along with the wall superheats for different oil bulk temperatures and the NN output was the corresponding heat fluxes. The developed NN model predicted boiling curves that are in close agreement with experimental data ( R2 ≈ 1). The NN was then trained on the experimental data of four of these oils and allowed to predict the boiling behaviour of the fifth. The NN, therefore, demonstrated its ability to predict the boiling characteristics of untested oils, provided their chemical compositions fall within the range of the training data. In addition, for oils with constituents outside the considered range, the NN was able to predict their boiling characteristics at all bulk temperatures when trained on a sample of experimental measurement. The success of such a technique provides researchers and developers of oils with the thermal performance of oils (based on chemical constituents) without testing or with very limited measurements. This, as a result, has the advantages of saving experimental time and cost of oil testing.
Interaction research of thiadiazole derivate and molybdenum naphthenate using X-ray absorption near edge structure spectroscopy
Authors: Zuo G , Li J , Ren T , Zhao Y , Zheng L , Ma C , Han Y
Published: December 2008

A four-ball tester was used to evaluate the anti-wear and friction-reducing performance of a blend of 2,5-bis((9,9-dimethyldecyl)disulfanyl)-1,3,4-thiadiazole (referred to as T561) and molybdenum naphthenate (referred to as MoNAP) in hydrogenated oils. The results indicate that the blend of T561 and MoNAP (referred to as TMoNAP) has excellent anti-wear and friction-reducing properties, as well as good load-carrying capacity. Then, X-ray absorption near edge structure (XANES) spectroscopy was employed to provide further insight into the chemical composition of films generated from thermal oxidation and friction process. According to the results, thermal films are composed mainly of ferrous sulphate, whereas anti-wear films are composed mainly of ferrous sulphide, ferrous disulphide, sulphite, ferrous sulphate, molybdenum disulphide, and molybdenum oxide. The mechanisms of friction reducing and anti-wear are discussed.
Tribology research in China: A personal view
Authors: Hu Y-Z
Published: December 2008

With the development of the economy and manufacturing industry, tribology research in China has experienced a fast growth over recent decades. This review gives an outline for the research progresses achieved by Chinese scientists and engineers in various subjects, including elastohydrodynamic lubrication (EHL) and mixed lubrication, nano-tribology, lubricants and additives, tribo-materials and coatings, tribology issues in biology and bionics, wear of materials, and tribological design that transfers research achievements to the design process of machine components. In comparison with the vastness of research activities and Chinese economy, this article is written by the present author, based on limited information and knowledge, but it may help tribologists around the world to get a better idea about what has been done by their counterparts in China, which would encourage communication and cooperation in tribology research.
From Newtonian dynamics to sparse Tableaux formulation and multi-body dynamics
Authors: Orlandea N V
Published: December 2008

This paper discusses the importance of the classical Newtonian mechanics on a new computer-oriented formulation called Sparse Tableaux Formulation (STF), which is the heart of Automatic Dynamic Analysis of Mechanical Systems. At the same time, it shows that such formulation can integrate different methods of numerical integration without disturbing its integrity. The STF is a modularized formulation as well as being open-ended. This will allow its development in time according to scientific and industrial demand. The paper shows that the physical systems can be mapped into mathematical representations that can be assembled in harmony with the system's structure, and the results of the computer simulations can be mapped back directly into the physical system.
Large-scale parallel multi-body dynamics with frictional contact on the graphical processing unit
Authors: Tasora A , Negrut D , Anitescu M
Published: December 2008

In the context of simulating the frictional contact dynamics of large systems of rigid bodies, this paper reviews a novel method for solving large cone complementarity problems by means of a fixed-point iteration algorithm. The method is an extension of the Gauss—Seidel and Gauss—Jacobi methods with over-relaxation for symmetric convex linear complementarity problems. Convergent under fairly standard assumptions, the method is implemented in a parallel framework by using a single instruction multiple data computation paradigm promoted by the Compute Unified Device Architecture library for graphical processing unit programming. The framework supports the simulation of problems with more than one million bodies in contact. Simulation thus becomes a viable tool for investigating the dynamics of complex systems such as ground vehicles running on sand, powder composites, and granular material flow.
Interpolation of finite rotations in flexible multi-body dynamics simulations
Authors: Bauchau O A , Epple A , Heo S
Published: December 2008

The representation and manipulation of finite rotations and the modelling of flexible bodies are at the heart of flexible multi-body systems dynamics simulations. When dealing with finite element formulations, the interpolation of finite-rotation fields becomes a critical issue. Objectivity, i.e. the invariance of interpolated strain fields to the addition of a rigid body motion, has been an important problem. Furthermore, the manipulation of finite rotations and the unavoidable associated singularities must be dealt in a rational manner. The various approaches to these two problems are reviewed in this article. Simple algorithms that achieve objectivity are proposed. Furthermore, these algorithms can deal with finite rotations of arbitrary large magnitude through a simple rescaling operation. The choice of unknowns, total versus incremental, is also discussed as it affects the performance of the computational process. Numerical examples are presented, which demonstrate the ability of the proposed approach to handle finite rotations of arbitrary magnitudes in complex, flexible multi-body systems.
Physics of causality and continuum: Questioning nature
Authors: Rahnejat H
Published: December 2008

This article commemorates three distinct periods in the growing understanding of physics of motion during the Renaissance (referring to advancement of art) period, the age of enlightenment (scientific renaissance: the Newtonian mechanics), and the adoption of field concept, embodied in the theory of relativity. Emphasis is put on Newton's immense and fundamental contributions and those of his immediate and subsequent contemporaries, leading to Lagrangian dynamics, which is the cornerstone of many contributions to this journal. In particular, a generic geometric interaction potential is introduced within a closed field, which conforms to Newton's law of universal gravitation and extends to the scale of microcosm, thus embedding gravity with other forces of nature. The implications of these extensions to the Newtonian potential are discussed.
Genital tract infections among HIV-infected pregnant women in Malawi, Tanzania and Zambia
Authors: Aboud S , Msamanga G , Read J S , Mwatha A , Chen Y Q , Potter D , Valentine M , Sharma U , Hoffmann I , Taha T E , Goldenberg R L , Fawzi W W
Published: December 2008

The aim of this study was to compare the prevalence and factors associated with genital tract infections among HIV-infected pregnant women from African sites. Participants were recruited from Blantyre and Lilongwe, Malawi; Dar es Salaam, Tanzania; and Lusaka, Zambia. Genital tract infections were assessed at baseline. Of 2627 eligible women enrolled, 2292 were HIV-infected. Of these, 47.8% had bacterial vaginosis (BV), 22.4% had vaginal candidiasis, 18.8% had trichomoniasis, 8.5% had genital warts, 2.6% had chlamydia infection, 2.2% had genital ulcers and 1.7% had gonorrhoea. The main factors associated with genital tract infections included genital warts (adjusted odds ratio [AOR] 1.8, 95% CI 1.2–2.7), genital ulcers (AOR 2.4, 95% CI 1.2–5.1) and abnormal vaginal discharge (AOR 2.5, 95% CI 1.9–3.3) for trichomoniasis. BV was the most common genital tract infection followed by candidiasis and trichomoniasis. Differences in burdens and risk factors call for enhanced interventions for identification of genital tract infections among HIV-infected women.
Assessment of risk for pulmonary tuberculosis after non-reactive tuberculin skin testing among patients with HIV infection in a resource-limited setting
Authors: Khawcharoenporn T , Apisarnthanarak A , Mundy L M
Published: December 2008

A cross-sectional study of 350 patients with HIV-1 infection was conducted to identify risks for pulmonary Mycobacterium tuberculosis (TB) after non-reactive two-step tuberculin skin tests (TST). Among 219 patients (62.6%) with non-reactive TST, independent risks for active pulmonary TB were prior known TB exposure (adjusted odds ratio [aOR] = 16.00, 95% confidence interval [CI] = 2.00–26.36, P = 0.008), CD4 <100 cells/μL (aOR = 2.50, 95% CI = 1.30–6.50, P = 0.04) and less than secondary-school education (aOR = 2.60, 95% CI = 1.50–6.90, P = 0.02). Our findings suggest that further diagnostic work-up for pulmonary TB is warranted among patients with HIV infection, non-reactive TSTs and either prior known TB exposure, CD4 counts <100 cells/μL or limited formal education.
Long-term follow-up study on peer-led school-based HIV/AIDS prevention among youths in Shanghai
Authors: Cai Y , Hong H , Shi R , Ye X , Xu G , Li S , Shen L
Published: December 2008

The HIV/AIDS epidemic is a major problem around the world and an increasing percentage of new HIV cases is reported to be by sexual transmission. Many studies have been carried out in the field of peer education on HIV/AIDS among young people, however, few studies focused on the long-term effect of this education. To evaluate both the short- and long-term effects of the peer education programme, we conducted a follow-up study to evaluate the related knowledge, attitudes and behaviour intention to HIV/AIDS among senior high-school students in Shanghai, China. We selected 1950 students from 10 senior high schools in Shanghai, from whom 968 students were selected at random for the intervention group and 982 students for the control group. The same questionnaires were carried out before intervention, one month and one year later in both the groups. In the intervention group, the knowledge score of reproductive health, HIV/AIDS and sexually transmitted disease rose from 21.66 to 31.72 one month later (P < 0.001). After one year it was still 30.97, and there was no significant difference between one month and one year (P > 0.05). The behaviour intention to HIV/AIDS prevention, such as condom use during sexual intercourse also changed before and after the intervention. After both the one month and one-year follow-up intervention, we found that more students declared that they would use condoms during sexual intercourse when compared with the control group (P < 0.001). No change was seen in either knowledge or behaviour intention in the control group. These results showed that peer education on HIV/AIDS prevention among high-school students is both effective in promoting knowledge and in changing behaviour intention long term.
Is vaginal microscopy an essential tool for the management of women presenting with vaginal discharge?
Authors: Lascar R M , Devakumar H , Jungmann E , Copas A , Arthur G , Mercey D
Published: December 2008

Point-of-care microscopy is the gold standard for the diagnosis of vaginal discharge in genitourinary (GU) medicine clinics but not used in primary care settings and reproductive health clinics to which many patients present. In our GU medicine clinic setting, we conducted an audit to assess the utility of microscopy of vaginal secretions versus clinical diagnosis alone for the differential diagnosis of uncomplicated lower vaginal infections. Clinical diagnosis (including pH) of bacterial vaginosis had a sensitivity between 85% and 88% at two clinic sites. Our results suggest that it may be safe and more cost-effective to restrict vaginal microscopy to a subgroup of women presenting with vaginal discharge.
Does the sexually transmitted infections foundation course deliver and change practice? Feedback from delegates 2002–2006
Authors: Richards J E , Pattman R S
Published: December 2008

Attendees at Newcastle sexually transmitted infections foundation (STIF) courses since 2002 were sent a postal questionnaire to ascertain views about the course, its effect on practice and the desire for further education. Totally 156 forms were returned (48% response). The majority 97% were satisfied with the course, 97% wanted updates, 57% annually and 33% biennially. Following a STIF course, 69% provided HIV testing (only 14% of those, prior to attendance). However, only 39% routinely offered HIV testing and only 34% routinely offered syphilis testing to patients whom they considered to be at risk of a sexually transmitted infection. Common reasons for not offering testing were lack of time for counselling, lack of confidence, no perceived need or anonymity concerns resulting in referral to genitourinary medicine. This was despite training, which encourages routine HIV testing with a pretest discussion rather than ‘counselling’ and education about recent outbreaks of syphilis.
Finite Element Analysis of the Proximal Femur and Hip Fracture Risk in Older Men
Authors: Orwoll Eric S , Marshall Lynn M , Nielson Carrie M , Cummings Steven R , Lapidus Jodi , Cauley Jane A , Ensrud Kristine , Lane Nancy , Hoffmann Paul R , Kopperdahl David L , Keaveny Tony M
Published: December 2008

Low areal BMD (aBMD) is associated with increased risk of hip fracture, but many hip fractures occur in persons without low aBMD. Finite element (FE) analysis of QCT scans provides a measure of hip strength. We studied the association of FE measures with risk of hip fracture in older men. A prospective case-cohort study of all first hip fractures (n = 40) and a random sample (n = 210) of nonfracture cases from 3549 community-dwelling men ≥65 yr of age used baseline QCT scans of the hip (mean follow-up, 5.6 yr). Analyses included FE measures of strength and load-to-strength ratio and BMD by DXA. Hazard ratios (HRs) for hip fracture were estimated with proportional hazards regression. Both femoral strength (HR per SD change = 13.1; 95% CI: 3.9–43.5) and the load-to-strength ratio (HR = 4.0; 95% CI: 2.7–6.0) were strongly associated with hip fracture risk, as was aBMD as measured by DXA (HR = 5.1; 95% CI: 2.8–9.2). After adjusting for age, BMI, and study site, the associations remained significant (femoral strength HR = 6.5, 95% CI: 2.3–18.3; load-to-strength ratio HR = 4.3, 95% CI: 2.5–7.4; aBMD HR = 4.4, 95% CI: 2.1–9.1). When adjusted additionally for aBMD, the load-to-strength ratio remained significantly associated with fracture (HR = 3.1, 95% CI: 1.6–6.1). These results provide insight into hip fracture etiology and demonstrate the ability of FE-based biomechanical analysis of QCT scans to prospectively predict hip fractures in men.
Single-Dose, Randomized, Double-Blind, Placebo-Controlled Study of ACE-011 (ActRIIA-IgG1) in Postmenopausal Women
Authors: Ruckle Jon , Jacobs Mark , Kramer William , Pearsall Amelia E , Kumar Ravindra , Underwood Kathryn W , Seehra Jasbir , Yang Yijun , Condon Carolyn H , Sherman Matthew L
Published: December 2008

The effects of ACE-011 on safety, pharmacokinetics, and bone biomarkers were evaluated in healthy, postmenopausal women. Our data indicate that ACE-011 results in a sustained increase in biomarkers of bone formation and reduction in markers of bone resorption. The activin type IIA receptor (ActRIIA) is the high-affinity receptor for activin. ACE-011 is a dimeric fusion protein consisting of the extracellular domain of the human ActRIIA linked to the Fc portion of human IgG1. ACE-011 binds to activin, preventing activin from binding endogenous receptors. A randomized, double-blind, placebo-controlled study was conducted to evaluate the safety and tolerability of ACE-011. Forty-eight healthy, postmenopausal women were randomized to receive either a single dose of ACE-011 or placebo and were followed for 4 mo. Dose levels ranged from 0.01 to 3.0 mg/kg intravenously and from 0.03 to 0.1 mg/kg subcutaneously. Safety and pharmacokinetic (PK) analyses and the biological activity of ACE-011, as assessed by markers of bone turnover, and follicle stimulating hormone (FSH) levels were measured. No serious adverse events (AEs) were reported. AEs were generally mild and transient. The PK of ACE-011 was linear over the dose range studied, with a mean half-life of 24–32 days. The absorption after subcutaneous dosing was essentially complete. ACE-011 caused a rapid and sustained dose-dependent increase in serum levels of bone-specific alkaline phosphatase (BSALP) and a dose-dependent decrease in C-terminal type 1 collagen telopeptide (CTX) and TRACP-5b levels. There was also a dose-dependent decrease in serum FSH levels consistent with inhibition of activin. ACE-011 is a novel agent with biological evidence of both an increase in bone formation and a decrease in bone resorption. ACE-011 may be an effective therapy in a variety of diseases involving bone loss.
FGF2 Stimulation of the Pyrophosphate-Generating Enzyme, PC-1, in Pre-Osteoblast Cells Is Mediated by RUNX2
Authors: Hatch Nan E , Li Yan , Franceschi Renny T
Published: December 2008

Pyrophosphate is an established inhibitor of hydroxyapatite deposition and crystal growth, yet when hydrolyzed into phosphate, it becomes a substrate for hydroxyapatite deposition. Pyrophosphate-generating enzyme (PC-1), Ank, and tissue nonspecific alkaline phosphatase (Tnap) are three factors that regulate extracellular pyrophosphate levels through its generation, transport, and hydrolysis. We previously showed that fibroblast growth factor 2 (FGF2) induces PC-1 and Ank while inhibiting Tnap expression and mineralization in MC3T3E1(C4) calvarial pre-osteoblast cells. In this study, we showed similar FGF2 regulation of these genes in primary pre-osteoblast cultures. In contrast to Ank and Tnap that are regulated by FGF2 in multiple cell types, we found regulation of PC-1 to be selective to pre-osteoblastic cells and to require the osteoblast-related transcription factor, Runx2. Specifically, FGF2 was unable to induce PC-1 expression in Runx2-negative nonbone cells or in calvarial cells from Runx2-deficient mice. Transfection of these cells with a Runx2 expression vector restored FGF2 responsiveness. FGF2 was also shown to stimulate recruitment of Runx2 to the endogenous PC-1 promoter in MC3T3E1(C4) cells, as measured by chromatin immunoprecipitation. Taken together, our results establish that FGF2 is a specific inducer of PC-1 in pre-osteoblast cells and that FGF2 induces PC-1 expression through a mechanism involving Runx2.
Water-Manometer Tensiometers Installed and Read from the Land Surface
Authors: Oaksford ET
Published: December 2008

Soil-moisture tension has been measured beneath an artificial-recharge basin in Suffolk County, Long Island, N.Y., with water-manometer tensiometers that can be installed and read from the land surface. The manometer-tensiometer unit is buried at the desired depth, and soil-moisture tension is measured from the land surface with a simple wire probe and electrical circuit that detect the level of water in the manometer. The water manometer is more sensitive than other common methods for determining unsaturated pressure head or soil-moisture tension over small ranges and is most helpful in situations where small changes in soil-moisture tension can reflect significant changes in hydraulic conductivity. Although the configuration may not be appropriate for installation at great depth (> 6 m) or in extremely coarse or fine soils, it provides rapid, reliable measurement of soil-moisture tension.
Testing of Geotechnical Fabric for Use as Reinforcement
Authors: Haliburton TA , Anglin CC , Lawmaster JD
Published: December 2008

Twenty-seven commercially available petrochemical-based geotechnical fabrics, both woven and nonwoven, and one fiberglass fabric were evaluated for suitability as reinforcement in an embankment test section to be constructed on soft foundation at Pinto Pass in Mobile Harbor, Ala. by the U.S. Army Corps of Engineers Mobile District. All fabrics were subjected to initial testing in uniaxial tension and fabrics meeting or exceeding established strength criteria were subjected to additional testing to determine creep behavior, soil-fabric frictional resistance, and the effects of immersion and water absorption on developed tensile strength. The effects of specimen width and testing strain rate on uniaxial tension test results were also investigated.

Four woven geotechnical fabrics plus the woven fiberglass fabric were found to meet or exceed required tensile strength criteria: Nicolon 66475, Nicolon 66186, Polyfilter-X, Advance Type I, and Bay Mills 196-380-000 (fiberglass). Both Nicolon materials were found to have minimal creep tendency and strength loss after soaking. Polyfilter-X was found to have moderate creep tendencies and high strength loss upon soaking, while Advance Type I was found to have high creep tendencies and moderate strength loss upon soaking. Bay Mills 196-380-000 had zero creep tendency and was not tested for soaking strength loss. Minimum soil-fabric frictional resistance for all five fabrics approximated soil-alone behavior for a loose relative density condition.
Multistage Triaxial Testing of Rocks
Authors: Kim MM , Ko H-Y
Published: December 2008

To determine the constitutive properties of the components in a rock structure, triaxial tests are commonly carried out on cylindrical test specimens. The conventional triaxial test (designated the single-stage triaxial test) involves obtaining a peak strength for the specimen and, after its breakage, a residual strength. In the multistage triaxial test, however, several peak and residual strengths can be obtained from a single specimen. This technique enables the experimenter to conserve samples and to obtain more consistent strength data by eliminating sample variabilities for the construction of failure envelopes. The feasibility of this test is examined by comparing strength results for single-stage and multistage tests in terms of the cohesion and the friction angle, which are calculated from the failure envelopes constructed by the two different types of test data. The feasibility is confirmed for Pierre shale and Raton shale, but is doubtful for Lyons sandstone, which is very brittle.
A Compilation of Cyclic Triaxial Liquefaction Test Data
Authors: Ferrito JM , Forrest JB , Wu G
Published: December 2008

A data base on cyclical soil strength would be of significant assistance in many phases of site evaluation where detailed complete cyclical soil testing is not available or could not economically be obtained. The objective of this study was to develop a partial data base for determining the seismic strength of saturated cohesionless materials, and, by using this data base, to broaden understanding of the mechanism of soil liquefaction induced in the laboratory.

The study is in support of efforts to mitigate the effects of earth-quakes through improved methods for determining the seismic strength of soils. To assist in this problem, cyclic triaxial test data were compiled from published literature and from commercial and research laboratories involved in cyclic testing of cohesionless soils; the data were organized, reviewed, and evaluated. Results were grouped by soil type (Unified Classification System). This data may assist geotechnical engineers to evaluate the seismic strength of cohesionless materials.
A Laboratory Method of Measuring In-Situ Density Distribution in Dry Sand
Authors: Singh G , Ergatoudis J , Siah BS
Published: December 2008

Powerful numerical methods are widely available for the solution of most soil-structure interaction problems. Reported numerical models have been able to account for most of the complexities involved. In contrast, the techniques for obtaining realistic soil material properties for input data are few in number. To address this need, an indirect way of measuring the in-situ density of sand has been devised. The technique is based on the fact that changes in density cause changes in thermal conductivity of the sand. The details and construction of a thermal probe employing unsteady-state heat flow principles are described. The reliability of the technique developed has been found to be excellent for the sand used. Results obtained indicate that there is a direct relationship between the density and thermal conductivity values of the sand. Calibration charts and equations relating density and thermal conductivity of sand are presented. This technique is considered to be superior to existing methods for measuring in-situ density of sands. Possible applications of the technique are suggested.
A Special Pressure Meter and Pressure Meter Test for Pavement Evaluation and Design
Authors: Briaud J-L , Shields DH
Published: December 2008

A special pressure meter and pressure meter test procedure have been developed specifically for use in pavement engineering. The probe of the pavement pressure meter is short and monocellular; single tubing is used; and the control unit is simple and designed for performing strain controlled tests. The probe is inserted in a predrilled 35-mm (1.38-in.) diameter hole and tests are performed every 300 mm (11.8 in.) down to a depth of 2000 mm (78.7 in.). A test curve is obtained at each interval of depth and a recompression modulus is obtained from each test curve. The recompression modulus profile can be used empirically or theoretically for the design of new pavements, for the evaluation of existing pavements, and for the design of overlays. The pavement pressure meter gives a direct evaluation of the deformation characteristics of each of the pavement and subgrade layers (except the surface course) at reduced cost. The apparatus is portable, easy to transport, and relatively inexpensive; the test itself is relatively rapid.
Strength and Stiffness of Silicate Grouted Sand with Different Stress Histories
Authors: Diefenthal DC , Borden RH , Baker WH , Krizek RJ
Published: December 2008

The effects of stress history and relative density on the short-term strength and stiffness of a granular soil (Ottawa 20–30 sand) that was chemically stabilized with a sodium silicate grout, a solution of hydrated sodium silicate, water, ethyl acetate, and formamide, were investigated. A system was developed to inject grout into sand specimens that were prepared in a triaxial cell; the specimens were subjected to a confining stress of 360 kPa and grouted under a pressure of 144 kPa. The results are analyzed in terms of Mohr-Coulomb failure theory, and comparisons are made among the compressive strength, initial tangent modulus, angle of internal friction, and cohesion of the specimens for different test conditions.

The strength of the specimens grouted under a confining stress is seen to be a function primarily of their relative density. Little difference in mechanical behavior was observed between specimens grouted under a confining stress and those grouted under at-rest conditions. The angle of internal friction of grouted specimens with a low or high relative density differed only slightly from that of ungrouted specimens with a low or high relative density. However, the compressive strength of loose and dense grouted specimens increases relative to that of ungrouted specimens because of an increase in the cohesion, although the initial tangent modulus of loose and dense grouted specimens is similar to that of dense ungrouted specimens.
On the Determination of Stress State in the Simple Shear Apparatus
Authors: Wood DM , Drescher A , Budhu M
Published: December 2008

The simple shear apparatus is one of the few commonly available laboratory apparatus that permits the application of controlled rotations of the principal axes of stress and strain to soil samples. However, because of the boundary conditions in the apparatus the soil sample does not respond as a single element, and this should be reflected in the analysis of test results. In the Cambridge University simple shear apparatus, the sample is surrounded by an array of load cells (contact stress transducers) that measure the complete distribution of boundary stresses throughout a test. For simple shear test results to be presented in terms of useful stress parameters, a procedure for computing the stress state from the load cell measurements is required. Such a procedure is described, making use of the concept of an average stress tensor to determine a representative stress state in the central part of the sample, which is least influenced by the ends of the apparatus.

Less complex and expensive apparatus exist that can only measure the average normal and shear stresses applied to the top and bottom horizontal boundaries of the sample. Patterns of soil response have been determined from tests on Leighton Buzzard sand in the more elaborately instrumented Cambridge apparatus, and a method is described for using these patterns to deduce the complete stress state in the less complex apparatus.
Fluid Cushion Truly Triaxial or Multiaxial Testing Device
Authors: Sture S , Desai CS
Published: December 2008

The derivation of the constitutive relations of soils requires a testing facility that can apply a homogeneous and nearly ideal set of controlled boundary conditions to a specimen. A new multiaxial cubical test apparatus is described. It uses fluid or pneumatically pressurized flexible cushions to transmit a three-dimensional, independently controlled, and compressive stress state to a 102-mm (4-in.) specimen of geologic material. The deformations in three orthogonal directions are detected by a set of linear variable differential transformers. Flexible cushions allow nearly unrestrained deformations in the specimen. The deformations are uniform even at large strains. The specimen preparation and apparatus assembly procedures are straightforward. The simplicity of the multiaxial cubical cell and its easy operating procedures are emphasized. Typical stress-strain curves for straight-line stress paths are discussed. The apparatus appears to operate especially well at low stress levels.
Chapter 1 Introduction
Authors: Dick JS
Published: December 2008

THE RUBBER INDUSTRY ESSENTIALLY STARTED IN 1839 when Charles Goodyear discovered vulcanization (the curing process). Since this date, a large industry has grown that manufactures thousands of rubber products such as tires, hoses, belts, seals, gaskets, bearings, bushings, mounts, etc. In fact, rubber is essential for a modern industrialized economy [1].
Chapter 8 Oils, Plasticizers, and Other Rubber Chemicals
Authors: Dick JS
Published: December 2008

PETROLEUM OILS ARE COMMONLY USED as extenders in styrene butadiene (SBR) and polybutadiene (BR) masterbatches purchased from synthetic rubber producers, as well as processing oils used in rubber formulations as a compounding ingredient. These oils differ in their chemical composition, which affects a rubber compound's processing behavior and its cured physical properties [1].
Manual on Elastic-Plastic Fracture: Laboratory Test Procedures
Authors: Joyce JA
Published: December 2008

Description

This manual will help you develop elastic-plastic fracture toughness data in accordance with the ASTM Test Method for J-Integral Characterization of Fracture Toughness (E 1737) and ASTM Test Method for Crack-Tip Opening Displacement (CTOD) FractureToughness Measurement (E 1290).

9 chapters provide guidance and instruction on equipment apparatus, test fixtures, transducers, test setup, test procedure, and data analysis. Through the use of test examples, example calculations, photographs of test apparatus and fracture samples, as well as expert advice and reference to papers in the literature describing various test techniques, MNL 27 gives you the next-best thing to hands-on training.

The chapters are organized sequentially, just as you would proceed to develop a laboratory capability to accomplish these fracture mechanics tests: Overview of Elastic-Plastic • Analysis • Apparatus • Specimen Preparation • Basic Test Procedure • Advanced Test Procedure • Qualification of the Test Results • Future Developments in Elastic-Plastic Fracture Testing • Appendix A: Software Listings (includes the text of an interactive unloading compliance data acquisition program written in Microsoft QuickBASIC) • Appendix B: ASTM Fracture Test Standards.

For mechanical and materials engineers; nuclear, civil, and aerospace structures engineers. Also for lab technicians and test mechanics.
Lead Hazard Evaluation and Control in Buildings
Authors: Ewing WM , Ewing EM , DePasquale C , Dawson TA
Published: December 2008

Description

This comprehensive ASTM manual provides detailed guidance for developing and implementing a lead hazard management program. It follows the outline described in ASTM E 2052-99 Standard Guide for Identification and Management of Lead Hazards in Facilities.

17 chapters cover the following fundamentals:

• Setting up and administering a lead hazard management program

• Designing and implementing an operations and maintenance program

• Collecting information on facilities for decision making purposes

• Classifying buildings based on their likelihood for lead hazards

• Evaluating buildings for lead hazards

• Responding to elevated blood lead investigation

• Conducting occupant education and awareness programs

• Hiring consultants, laboratories, and contractors

• Planning and performing lead hazard control activities

• Ongoing monitoring and reevaluation of lead hazards

• Role of lead hazard programs in real estate transactions.