bluuebunny/crossref_metadata_2025 huggingface dataset:
Should psychiatrists be prescribing oestrogen therapy to their female patients?
Authors: Craig Michael C.
Published: January 2013

Some studies have indicated that oestrogen therapy may be beneficial in the treatment of a number of neuropsychiatric disorders. However, it has been suggested that psychiatrists fail to prescribe oestrogen therapy to their patients, as they are ‘not aware of or ‘do not believe’ studies supporting their use. This paper reappraises the putative role of hormone treatments, particularly oestrogen therapy, in psychiatry.
Structural and copy number variants in the human genome: implications for psychiatry
Authors: Clair David St
Published: January 2013

Copy number variants are small chromosomal deletions and duplications. When they alter the dose of genes critical for normal brain development and adult brain functioning they may cause severe disorders such as autism and schizophrenia. Numerous such loci have recently been identified. They are offering amazing leads for neuropsychiatric research.
Differential mortality rates in major and subthreshold depression: meta-analysis of studies that measured both
Authors: Cuijpers Pirn , Vogelzangs Nicole , Twisk Jos , Kleiboer Annet , Li Juan , Penninx Brenda W.
Published: January 2013

Background

Although the association between depression and excess mortality has been well established, it is not clear whether this is greater in major depression than in subthreshold depression.

Aims

To compare excess mortality in major depression with that in subthreshold depression.

Method

We searched bibliographic databases and included prospective studies in which both major and subthreshold depression were examined at baseline and mortality was measured at follow-up.

Results

A total of 22 studies were included. People with major depression had a somewhat increased chance of dying earlier than people with subthreshold depression but this difference was not significant, although there was a trend (relative risk 1.13, 95% CI 0.98-1.30, P=0.1). The population attributable fraction was 7% for major depression and an additional 7% for subthreshold depression.

Conclusions

Although excess mortality may be somewhat higher in major than in subthreshold depression, the difference is small and the overall impact on excess mortality is comparable.
Hypochondriasis and health anxiety: conceptual challenges
Authors: Starcevic Vladan
Published: January 2013

The relationship between hypochondriasis and health anxiety is examined by considering a DSM-5 proposal to replace the current heterogeneous concept of hypochondriasis with two disorders. The key issues are to ascertain whether these conditions are relatively distinct and whether they adequately represent the full range of clinical manifestations encompassed by hypochondriasis.
Use of electronic health records in identifying drug and alcohol misuse among psychiatric in-patients
Authors: Bell James , Kilic Cise , Prabakaran Reena , Wang Yuan Yuan , Wilson Robin , Broadbent Matthew , Kumar Anil , Curtis Vivienne
Published: January 2013

Aims and method

To assess the usefulness of the electronic patient record, we used the search engine Clinical Record Interactive Search (CRIS) to scan all acute admissions during 2008 for possible substance use disorders. In addition, screening interviews were undertaken with 75 in-patients, and documentation in their files was compared with results of screening interviews.

Results

Of 839 acute admissions during 2008, 47% of males and 29% of females had reference to a substance misuse problem in their file. Documentation was unsystematic and inconsistent and mostly occurred in progress notes rather than in structured questionnaires. Screening interviews and manual review of files of 75 current in-patients confirmed that substance use disorders were common, but poorly documented.

Clinical implications

The study highlights the power of search engines in scanning electronic clinical records, but also identified the limitations of unsystematic documentation in research and practice. Mental health staff were reluctant to diagnose or rate severity of substance misuse problems.
Fanon’s Two Memories
Authors: Drabinski John E.
Published: January 2013

This essay frames Fanon’s work on revolutionary consciousness in The Wretched of the Earth with the problem of memory. In particular, it asks how Fanon’s conception of the colonized is underwritten by a double-movement of remembering and forgetting. The colonized must remember grievance against the colonizer and gather the affect of rage into a will to act. At the same time, the colonized must forget memories of intra-African violence and the grievances produced by that violence. Fanon’s two memories, then, create an undecidable tension of memory and history at the heart of his project in The Wretched of the Earth.
Concerning Maoism: Fanon, Revolutionary Violence, and Postcolonial India
Authors: Gopal Priyamvada
Published: January 2013

This essay assesses the translatability, across historical contexts, of Frantz Fanon’s iconic theory of revolutionary violence. It examines Fanon’s work through the prism of the Maoist insurgency in India alongside relevant writings by Arundhati Roy and K. Balagopal.
The Labor Question in China: Apple and Beyond
Authors: Litzinger Ralph
Published: January 2013

This essay introduces recent efforts by activists, NGOs, and academics to investigate and report on the working conditions for Chinese workers along Apple’s supply chain in China. Tracking the “suicide express” at the Foxconn factory complex in Shenzhen in 2010, the work of the Hong Kong–based activist labor organization Students and Scholars against Corporate Misbehavior, a coalition of environmental organizations headquartered in Beijing, and reporting by journalists, the essay shows how Apple was forced to go public about the myriad environmental, health, and labor problems in its outsourced factories. This essay also reflects on the theatrical activism and controversy surrounding Mike Daisey’s “The Agony and the Ecstasy of Steve Jobs.” Finally, highlighting the arguments of the three contributions to this section, it shows how China’s new generation of workers is increasingly educated and gives voice to a range of desires and perspectives about the Chinese state, its relationship to global capital, and the ways of life, living, and labor for workers in the electronics industry.
Labor Politics Under Three Stages of Chinese Capitalism
Authors: Hung Ho-fung
Published: January 2013

This essay outlines the three stages of Chinese capitalist development in the 1980s through the 2000s and discusses how labor politics played out differently in each of the three stages and helped shape the next stage. Whence the erosion of living standards of urban workers amid out-of-control inflation and corruption in the late 1980s led to workers’ participation in the 1989 democratic movement, the full-fledged neoliberal reforms implemented by the post-1989 authoritarian state in the 1990s urged many laid-off workers in state enterprises to take to the streets. In the wake of these struggles by the declining rank of socialist state workers was the surge of militant resistance by the new working class in the export sector after China’s accession to the World Trade Organization in 2001. Whereas local states and private manufacturers colluded to repress these new workers’ struggles, the center of the Chinese Communist Party, concerned about social stability and rebalancing China’s economy through raising workers’ share of income and consumption, has increasingly sided with the struggling workers to contain the alliance between local states and private capital. The outcome of this new labor politics will be a key factor in determining the Chinese model of development in the years to come.
Cognitive Abilities and Household Financial Decision Making
Authors: Agarwal Sumit , Mazumder Bhashkar
Published: January 2013

We analyze the effects of cognitive abilities on two examples of consumer financial decisions where suboptimal behavior is well defined. The first example features the optimal use of credit cards for convenience transactions after a balance transfer and the second involves a financial mistake on a home equity loan application. We find that consumers with higher overall test scores, and specifically those with higher math scores, are substantially less likely to make a financial mistake. These mistakes are generally not associated with nonmath test scores. (JEL D14, G21)
Do Oil Windfalls Improve Living Standards? Evidence from Brazil
Authors: Caselli Francesco , Michaels Guy
Published: January 2013

We use variation in oil output among Brazilian municipalities to investigate the effects of resource windfalls on government behavior. Oil-rich municipalities experience increases in revenues and report corresponding increases in spending on public goods and services. However, survey data and administrative records indicate that social transfers, public good provision, infrastructure, and household income increase less (if at all) than one might expect given the higher reported spending. (JEL H41, H75, I31, O13, O15, O17, O18)
Disturbance Effect on Time-Dependent Yield Stress Measurement of Bentonite Suspensions
Authors: Yoon Jisuk , El Mohtar Chadi
Published: January 2013

Disturbance effect on time-dependent yield stress measurement of bentonite suspension was investigated using vane and cone and plate geometry. With cone and plate geometry, the disturbance occurs as a result of the large strains the suspensions are subjected to when placed on the lower plate and when the cone is lowered to the testing position before the actual shear stress is applied. As an alternative, vane geometry has been used to measure yield stress in bentonite suspension to (1) minimize the placing disturbance, and (2) eliminate the loading disturbance. Even though a minimal amount of disturbance was still induced by vane geometry, it was assumed that the amount of disturbance was small enough to be ignored compared to that with cone and plate geometry. Yield stresses of bentonite suspensions at different weight fractions and various resting times were determined from stress ramp tests. Linear relationships were developed between yield stresses measured with the different geometries. Disturbance rapidly increased up to approximately 50 % with resting times, then converged at long resting times (60 % at 10 days). This indicates that cone and plate geometry significantly underestimated the actual yield stress of the tested material because of disturbance. Based on the quantified disturbance, a method to predict the undisturbed yield stress from disturbed one was proposed. The observations were interpreted with structural kinetics.
Fatigue Analysis of Asphalt Concrete under Indirect Tensile Mode of Loading Using Crack Images
Authors: Nguyen Manh Tuan , Lee Hyun Jong , Baek Jongeun
Published: January 2013

In this study, various fatigue criteria for indirect tensile (IDT) fatigue tests were evaluated and a new approach to identify the fatigue failure was proposed based on a crack-length criterion. The IDT fatigue tests were conducted to characterize the fatigue behavior of various asphalt mixtures, such as three warm mix asphalt mixtures and a polymer-modified asphalt mixture. During the IDT tests, digital cameras were mounted to monitor crack growth on the both faces of a specimen. Existing three fatigue failure criteria were evaluated regarding to fatigue-crack development. Then, a crack-length limit was proposed as a fatigue criterion. The IDT strength tests were also conducted to determine fracture energy of the mixtures. Based on the new fatigue criterion, a fatigue performance model was constituted with dissipated and fracture energy parameters. The fatigue model proposed in this study successfully predicted the fatigue lives of the mixtures with a high level of accuracy. The main advantage of this fatigue model is that it does not need a transfer function to convert the fatigue life to crack length or area, because fatigue-crack length is directly determined from the crack-length limit.
Effect of Working Parameters on Excavation Rate and Specific Energy on Surface Treatment With Pure Water Jet
Authors: Ozcelik Yilmaz , Ciccu Raimondo , Bortolussi Augusto
Published: January 2013

The purpose of this study is to investigate the effect of different operational variables such as traverse velocity, standoff distance, and pump pressure on the material removal rate (excavation rate) and specific energy in the surface treatment of stone with a pure water jet. In this study, these have been evaluated as performance parameters, and a specific method has been developed for material removal measurements and calculations. A set of 27 raster scanning tests was performed with a constant nozzle diameter (0.3 mm), distance between jet sweep lines (1.5 mm), and angle of inclination of the jet (30°) and varying standoff distances (50, 100, and 150 mm), traverse velocities (5, 15, and 25 m/min), and pump pressures (200, 250, and 300 MPa). It is observed that the excavation rate decreases as the standoff distance increases, whereas it increases with pressure. The specific energy increases with traverse velocity, standoff distance, and pressure, although it is not considered whenever the nozzle is moved fast and positioned away from the target.
Aircraft Turbine Engine Manufacturing with Multiple Specifications
Authors: Lin S. J. , Yang D. L. , Cheng F. T. , Wu M. F.
Published: January 2013

The blade is a key part of an aircraft engine because its geometry and manufacturing quality affect engine performance and the lift time of the airplane. Therefore, blade inspection is a key aspect of engine quality. Measuring and analyzing airfoil section parameters and geometric tolerance are essential but complex tasks in blade inspection. This study focuses on the airfoil geometry. Dimensional inspection of complex geometry parts by coordinate measuring machines is a common practice in both the automotive and aerospace industries. The conventional approach is to accept or reject parts according to inspection data. This study used a method of evaluating the capability of the blade manufacturing process to produce blades that conform to the profile specifications. The blade is possessed of multiple characteristics. All these characteristics influence the blade manufacturing process yield. An overall yield measure index CpkT is used for performing accurate yield assessments of processes with multiple characteristics. That is, the index is a generalization of the index Cpk. The applied method measures the process capability to produce a blade that meets the manufacturing specifications considering multiple product quality characteristics, including the segments of the airfoil section.
Pavement Performance of Asphalt Surface Course Containing Reclaimed Asphalt Pavement (RAP)
Authors: Hu Xudong , Nie Yihua , Feng Yu , Zheng Qisen
Published: January 2013

Reclaimed asphalt pavement (RAP) provides many advantages. The performance of a provincial road with an asphalt surface course containing RAP in Zhejiang, China was evaluated. The surface course was prepared by central plant hot mix recycling and virgin asphalt concrete. An AC-13 was chosen as gradation design in all mixes. The performance of asphalt mixture (containing 0 %, 10 %, 20 %, and 30 % RAP) was evaluated in the laboratory for fatigue resistance condition, moisture susceptibility, high-temperature stability, and low-temperature anti-cracking. Based on the laboratory results, the provincial road was constructed consisting of three sections (corresponding to 0 %, 10 %, and 20 % RAP content) in surface course with a 30-mm depth. The field site has been inspected and observed for 4 years. The field testing included deflection, skid resistance, permeable performance, and evenness evaluations. The laboratory test results show that all the testing indices satisfied the demand of the specifications, except moisture susceptibility and low temperature anti-cracking performance of the recycled asphalt concrete, including 30 % RAP. The inspection data proved that a small percentage of RAP unaffected the surface course performance, but RAP ratios greater than 20 % are not suitable in the mainline for high-volume roadways.
Viscoelastic Performance Analysis of Sulfur-Modified Asphalt Mixture
Authors: Hou Rui , Guo Zhong-yin
Published: January 2013

To understand the viscoelastic performance of sulfur-modified asphalt mixture, the penetration test and dynamic modulus test are used to analyze binder and mixture performance with different sulfur content. These test results show that lower sulfur concentration in the binder will increase asphalt mixture’s viscosity and temperature sensitivity. But higher sulfur concentration in the binder will increase asphalt mixture’s elasticity and reduce temperature sensitivity.
State of the Art of Asphalt Surfacings on Long-spanned Orthotropic Steel Decks in China
Authors: Chen Xianhua , Qian Zhendong , Liu Xueyan , Lei Zhang
Published: January 2013

Reliable and durable asphalt surfacing systems still are desired for long-spanned orthotropic steel bridges according to national and international reports on distresses in deck pavement. Based on ten-year research works, this paper presents a brief review and discussion of the practices and experiences of deck pavement on long-spanned steel bridges in China, including issues of typical surfacing materials and their properties, main distresses in asphalt surfacing, and the basic characteristics of asphalt surfacing on orthotropic steel bridge decks. It is concluded that the behaviours of deck pavement on orthotropic steel bridge decks under truck loads are complex as a result of geometric and material-dependent nonlinearity, coupling the global dynamic effects of the whole bridge system. More efficient computational techniques are still desirable for coupling global effects with local responses, counting the interfacial effects and interactions, and evaluating the effect of the predominant distress of fatigue cracking and de-bonding on the service life of this type of structure.
Study on the Curing Process of Epoxy Asphalt
Authors: Wei Jianming , Zhang Yuzhen
Published: January 2013

In the present study, the curing process of epoxy asphalt was studied using Fourier transform infrared spectroscopy (FTIR) with attenuated total reflectance, fluorescent microscopy morphology, and surface free energy. FTIR was utilized to track the functional group changes in epoxy resin (part A) and asphalt containing a curing agent (part B) at different curing times. It is proposed that the curing agent (hardener) in the asphalt (part B) is a carboxylic acid. The curing process is the reaction between the carboxyl group and the epoxy group through which the ester carbonyl group is formed, whereby carbonyl acid molecules and epoxy molecules are bound together to form a cross-linked network. The fluorescent microscopy morphology analysis indicates that the cross-linked network did not form at the beginning of the reaction. In the cured epoxy asphalt system, the epoxy resin is the continuous phase, and the asphalt constitutes the dispersed phase. The sessile drop method was employed to measure the static contact angle between asphalt binders and three probe liquids. The surface free energies of the epoxy asphalt at different curing times were determined using the Owens–Wendt method. Contact angle and surface free energy measurements indicate that the polarity of epoxy asphalt was reduced and the dispersion part was increased with the extended curing time.
Gradation Design of the Aggregate Skeleton in Asphalt Mixture
Authors: Zhao Yongli , Xu Tao , Huang Xiaoming , Li Zhidong
Published: January 2013

Rutting is one of primary distresses in asphalt pavements. The asphalt mixtures with strong aggregate skeleton have a good rutting resistance. The gradation design method of coarse aggregate skeleton and asphalt mixture was studied. A three-dimensional spheroid model was used to analyze the mechanical characteristics of the aggregate skeleton. The aggregate crushing test and the Marshall compact test were conducted to verify the theoretical analysis. The results show that the stability of aggregate skeleton was improved by increasing the number of contact points. And a gradation design model was developed for the coarse aggregate skeleton. 4.75 mm was defined as the dividing size between coarse and fine aggregates. The asphalt content and performance-related volume parameters were introduced into the design method. It ensures the aggregate skeleton formation and the desired performance of asphalt mixtures. The aggregate gradation is very similar to that of SMA, and that the designed asphalt mixture has good high-temperature performance. It is concluded that the proposed design method a have good practical applicability.
Relationship between Degree of Anisotropy of Asphalt Concrete and Its Geometrical Parameters
Authors: Li Chang , Ju Da
Published: January 2013

The property of anisotropy is an inherent characteristic of asphalt concrete (AC) and is mainly created by the nonuniform distribution of aggregates. Although there are some previous studies on the subject, a universal anisotropic model is still unavailable. This paper selects an AC type frequently used in China, AC-20, and tries to establish a usable statistic regression relation to predict the degree of anisotropy. Specimens are fabricated and tested. Then regression equations are obtained, and the effects of different geometrical parameters are investigated. It can be concluded that the average long axis angle is more important than deviation from the gravity center. In resilient modulus experiments of this research, the anisotropic degree of AC-20 ranges from 0.78 to 0.85. It comes mainly from the largest granules in aggregates. The AC type that has the smaller nominal maximum particle size will have less anisotropic tendency. As for AC-20, the anisotropy tendency will be neutralized by granules smaller than 13.2 mm, and the most effective granules have sizes between 4.75 mm and 9.5 mm.
A New “Mix-confined” Repeated Load Test for Evaluating Permanent Deformation of Asphalt Mixture
Authors: Liao G. Y. , Xiang J. Y. , Huang X. M. , Yang Y. W.
Published: January 2013

Existing tests for evaluating the permanent deformation of an asphalt mixture have many problems, such as the fixed confining pressure for repeated load triaxial tests (RLTTs). The main objectives of this paper are to develop a new “mix-confined” test and to compare the accuracy and sensitivity of this test with those of RLTTs. A new mix-confined repeated load test (MCRLT) is developed to measure the permanent deformation of two types of test specimens, including field cores extracted from asphalt pavement and lab-mixed specimens. The accuracy and sensitivity of the MCRLT are compared with those of an RLTT. The results show that during the MCRLT the test specimen can provide some (but not enough) confining pressure itself (so-called mix-confined). MCRLTs have slightly higher accuracy and lower sensitivity than RLTTs. The MCRLT can be a good alternative to the RLTT for evaluating the permanent deformation of asphalt mixtures, especially when there is no RLTT equipment available.
Aging Behaviour and Mechanism of SBS-Modified Asphalt
Authors: Ma Tao , Huang Xiaoming , Zhao Yongli , Yuan Hao
Published: January 2013

The aging behaviour and mechanism of styrene-butadiene-styrene (SBS)-modified asphalt has been investigated based on laboratory tests in this study. Rolling thin-film oven (RTFO) test and pressure-aging-vessel (PAV) test were conducted to prepare aged SBS-modified asphalt. Conventional property tests, including penetration, soften point, and ductility, as well as elastic recovery and SHRP property tests, including viscosity, dynamic shear rheometor (DSR) and bending-beam rheometer (BBR) tests, were mainly used to analyse the aging behaviour of SBS-modified asphalt. Then Fourier transform infrared spectroscopy (FTIR) and gel-permeation chromatography (GPC) tests were conducted to capture the aging mechanism of SBS-modified asphalt. The testing results indicated that SBS-modified asphalt has similar aging behaviour as base asphalt but better performance and anti-aging ability because of the existence of the SBS modifier. However, it is still inevitable that SBS-modified asphalt becomes aged because of thermal oxidation. The aging of SBS-modified binder consists of two parts: (i) the oxidative aging of the asphalt components, and (ii) the degradation of the SBS modifier. Because of the protective effect between asphalt and SBS polymer, the aging degrees of asphalt and SBS polymer were lower than those aged independently.
Research on ERS Steel Deck Pavement Techniques
Authors: Youqiang Pan , Zhixiang Zhang , Rongji Cao
Published: January 2013

Steel bridge deck pavement has been considered as a worldwide engineering problem, especially in China. During the past decade, many famous long-span steel bridges have been built in China, for example, Sutong Yangze River Bridge. However, some serious deterioration on the steel bride deck pavement happened when it was opened to traffic because of the heavy traffic and high temperatures. Based on the analysis on the construction problem of steel deck pavement and special traffic and environmental conditions in China, a new kind of steel deck pavement structure, called epoxy–resin–stone (ERS) steel deck pavement, is presented in this paper. It contains three main layers, i.e., epoxy bonding chips layer (EBCL), resin–asphalt mixture (RA05), and stone mastic asphalt (SMA). EBCL is introduced to act as a waterproof, bonding, and slipping proof layer; RA05 is used as an intermediate layer; and SMA is used as a surface functional layer. Test results and engineering practice show that ERS steel deck pavement has excellent performance and good workability. The technique has been applied in more than 10 steel bridges. It is helpful to solve the difficult steel deck pavement problem in China.
Understanding Melt Index and ASTM D1238
Authors: Mertz A. M. , Mix A. W. , Baek H. M. , Giacomin A. J.
Published: January 2013

In plastics manufacturing, the melt flow index (MFI) is used as a routine indicator of rheological behavior when more expensive and laborious determinations of well-defined material functions are impractical. The MFI is the mass flow rate in a pressure driven flow through a standardized abrupt cylindrical contraction into a short tube performed under a standardized combination of pressure drop and temperature. In this paper, we use a finite element model to explore the connections between rheological properties and melt index. We explore the role of shear thinning by modeling the flow through the melt indexer using the Bird-Carreau model. We then explore the role of melt viscoelasticity in the MFI using the corotational Maxwell model. We present our results in dimensionless charts designed to help plastics engineers specify the MFI of a plastic for an industrial manufacturing process of known material functions. Worked examples are included to show how to use the results.
Rutting Mechanism Analysis of Heavy-duty Asphalt Pavement Based on Pavement Survey, Finite Element Simulation, and Instrumentation
Authors: Dong Zejiao , Tan Yiqiu , Cao Liping , Li Shenglong
Published: January 2013

The vertical strain of an asphalt layer is essentially important when identifying rutting mechanisms or causes in asphalt pavement with a semi-rigid base course, which is a typical pavement structure in China. As a result, three directional strain measurements (longitudinal, transverse, and vertical strain) in the field, together with a pavement rutting survey and finite element simulation, were carried out in order to clarify the causes of rutting happening in Beijing heavy-duty expressways. First, the basic principal of a fiber Bragg grating sensor is explained, followed by the introduction of sensor installation in the field. Then, a three-dimensional finite element pavement model subjected to a non-uniform moving load was established to validate the dynamic response measurement on site. Finally, based on a comprehensive analysis including a pavement condition survey, numerical simulation, and strain measurement, the rutting mechanism of heavy-duty asphalt pavement in Beijing is discussed. The results show that the occurrence of shear deformation within asphalt layers results in the rutting development, in which material weakness, modulus mismatch of asphalt layers, and heavy-duty characteristics play important roles. Optimizing asphalt layers’ moduli, i.e., making them match, might make pavement bear the applied loading with integrity, thus averting the occurrence of excessive local strain, i.e., rutting.
Feature Assimilation for Vibration Based Damage Detection
Authors: Prabhu Saurabh , Atamturktur Sez
Published: January 2013

Structural health monitoring (SHM) technology for the early detection and mitigation of adverse structural effects, such as degradation or damage, is useful for enhancing the proactive maintenance of civil infrastructure. SHM techniques are advantageous because they eliminate the need for both a priori knowledge of the location of damage and access to the damaged portion of the structure. The underlying principle behind SHM involves measuring changes in a system’s vibration response, which ultimately indicate changes in physical properties due to structural damage. A challenge to the successful application of SHM to civil infrastructure is the selection of suitable vibration response features that are highly sensitive to the presence and extent of damage while also having low sensitivity to extraneous noise. This study reveals that both damage and the noise sensitivity of vibration response features vary for different states of structural health; therefore, the selection of optimum features is dependent on the damage severity, which is of course not known a priori. This study illustrates that assimilating multiple low-dimensional features lessens this dependence and improves the sensitivity of the damage indicators for SHM diagnosis.
Evaluation of Performance on Crumb-Rubber-Modified Asphalt Mixture
Authors: Dong Yuming , Tan Yiqiu , Yang Liying
Published: January 2013

This paper investigates the performance of crumb-rubber-modified (CRM) asphalt mixture. Two different asphalt mixtures containing two types of asphalt binder (#90 original asphalt and CRM asphalt) were used to prepare Marshall specimens and determine optimum asphalt content. Mechanical performances of asphalt mixes were evaluated by the wheel rutting test (WRT) (dynamic stability (DS)), midpoint beam bend test (MBBT), at low temperature, and indirect tensile test (IDT), at the freezing and thawing cycle. Superpave gyratory compactor (SGC) specimens were also prepared for the modulus test. Using the simple performance test (SPT) and universal testing system (UTS), viscoelastic mechanical characteristics were evaluated by static and dynamic modulus tests. Static modulus (E) data were measured by the un-confinement uniaxial compression test according to the specification of China. Moreover, dynamic modulus (E0) data were obtained by SPT. The crumb-rubber content varies from 0, 10 %, 20 %, to 30 % at the static modulus test. Two test temperatures were selected for the dynamic modulus test. The results indicated that the CRM asphalt mixture performs better than the standard asphalt mixture on dynamic behavior, rutting resistance, cracking resistance, and moisture stability.
Fundamental Principles of Contact and Lubrication
Authors: Wang Q. Jane , Cheng Herbert S.
Published: January 2013

Tribological interfaces involving contact and relative motion are everywhere in modern machinery for power transmission and function accomplishment. Automotive power generation and drivetrain systems, as well as many other motion control systems, contain various tribological interfaces. The contact of components produces stresses and the relative motion between surfaces results in rubbing. Therefore, a tribological interface is an environment where energy is consumed and materials are worn out; it is also the critical location where many failures are initiated. Designing energy-efficient and robust mechanical systems requires understanding of tribological interfaces, and the theories of contact and lubrication are two fundamental areas. This chapter summarizes fundamental theories and practices of surface, contact and lubrication analyses.
Automotive Lubricants
Authors: Mackney Derek , Clague Nick , Brown Gareth , Fish Gareth , Durham John
Published: January 2013

A lubricant has to perform many functions to effectively lubricate the various parts of a vehicle. These functions include

• Reduction of friction and wear,

• Removal of heat,

• Removal of contaminants,

• Protection of surfaces from corrosion,

• Cleaning of surfaces, and

• Neutralization of acids formed during combustion.
Automotive Engine Hardware and Lubrication Requirements
Authors: Becker Edward P. , Tung Simon C.
Published: January 2013

The automotive industry is facing tough international competition, government regulations, and rapid technological changes. Ever-increasing government regulations require improved fuel economy and lower emissions from the automotive fuel and lubricant systems. Higher energy-conserving engine oils and better fuel-efficient vehicles will become increasingly important in the face of the saving of natural resources and the lowering of engine friction. Recently, industry research needs for reducing friction and wear in transportation are critical for saving fuel economy and extended vehicle reliability. There are many hundreds of tribological components, from bearings, pistons, transmissions, and clutches to gears and drivetrain components. The application of tribological principles is essential for the reliability of the motor vehicle and the energy conservation of our environment. This review chapter will provide a comprehensive overview of various lubrication aspects of a typical powertrain system including the engine, transmission, driveline, and other components as well as the major issues and the current development status for automotive engine lubricants in North America. This review chapter also describes the major functions of typical engines (gasoline and diesel), engine oil characteristics, and test methods. Included are descriptions of the tribological concerns associated with various engine components, service effects on engine oil, standard automotive tests for engine oil and the types of service they represent, and an overview of the current issues and future trends that needs to be addressed.
Automotive Bearing Systems—Journal Bearings
Authors: Mian Omar
Published: January 2013

The principal use for journal bearings in automotive applications is for the crankshaft bearings, piston pin joint, balancer shafts, and crankshafts. These can either be half shells in which a split is required for assembly (e.g., crankshaft bearings) or bushes that can be inserted without a split (e.g., piston pin joints). For engine bearings, the oil is normally supplied at pressure from the oil pump via a filter/ cooler assembly to a main oil gallery that runs along the side of the engine and then to the main bearing as indicated in Figure 8.1. The oil supply hole in the upper main bearing normally feeds into a groove so that a drilling in the crankshaft journal can transport the oil to the big-end bearing in the connecting rod. Oil supply to the pin joint small-end and piston pin boss is typically by “splash” from the sides of the or via internal drillings in the connecting rod or piston. During the design process, the assembly must be considered as a “system” with adequate lubricant supply and clearance shape—the bearings are often the “fuse” where any deficiencies become obvious in damage such as engine seizures. The normal design envelope for journal bearings is indicated by:

• Maximum specific load (MSL): MSL is the applied load divided by the projected area (length × diameter). Typical values are 30–70 MPa for “bimetal” bearings and 60–100 MPa for “trimetal” bearings. Overloading can result in loss of the lining by fatigue mechanisms or “swaging”/plastic flow of material near edges.

• Minimum oil film thickness: This is where the oil film is not able to completely separate the surfaces and the opposing sliding surfaces or tips of surface asperities start to contact each other with potential wear, flash temperatures, or seizure. Typical surface roughness values (Ra) are approximately 0.2 µm for crankshaft journals and 0.05 µm for gudgeon/piston pins. High temperatures can result from “mixed” or “boundary” lubrication conditions because the friction coefficient for a lubricated contact is approximately 1 or 2 orders of magnitude less than that for “dry” friction. At high engine speeds (6000–7000 r/min, gasoline engines), localized thin film areas can result in heat generation and hot spots within the oil because of high shearing.

• Shearing of oil within the clearance space: This can further increase the bearing surface temperatures by up to approximately 20–50°C higher than the supply temperature, which can result in overheating of the bearing. During engine operation, the oil sump or bearing oil supply temperatures can reach approximately 100–155°C. Under some load-speed conditions, bearing surface temperatures of 190°C or more are possible where some components within the bearing alloy such as tin can start to melt, causing engine seizures if the high temperatures are sustained. Prolonged periods of engine running at high temperatures can also lead to the degradation of oil where soot-like material or lacquers can clog up oil passages and leave a dark residue on the bearing running surface.
Dynamic Friction Characterization and Modeling of Tripod Constant Velocity Joints
Authors: Lee Chul-Hee , Polycarpou Andreas A.
Published: January 2013

Constant velocity (CV) joints are an integral part of modern vehicles. CV joints exhibit superior vibration performance compared with universal joints because they eliminate uneven rotating torque via their self-centering ability. CV joints provide coupling forces and moments between connected substructures as well as localized damping dissipation [1,2]. In modern vehicles, CV joints have become a standard design of driveshaft for front-wheel-drive (FWD) passenger cars. Figure 25.1 shows a typical FWD configuration in a vehicle with driveshaft installations. Each driveshaft comprises two types of CV joints—namely fixed (outboard) and plunging (inboard) types—connected via a shaft, and their primary function is to transmit the engine torque to the wheels with CV. In this work, the emphasis is on a class of plunging CV joints called tripod CV joints, as shown in Figure 25.2, which have been especially favored for automatic transmission vehicles. This is because of their noise and vibration advantages because they offer lower plunging resistance compared with ball-type joints [1]. Note that tripod CV joints also fulfill the conditions of CV operation [1].
Biobased Automotive Lubricants
Authors: Honary Lou A.
Published: January 2013

There is a new impetus for the use of vegetable oils or renewable oils in automotive applications. The environmental factor promises to be a more steady and persistent force in promoting the use of these products than the fluctuating availability of petroleum. However, increased demand for petroleum by emerging economies has led to an increase in the need for petroleum substitutes. Either because of imposed environmental regulations or society's desire for a more environmentally friendly lubricant, the interest and increased use of vegetable-based engine oils and industrial lubricants will continue. Every year in the United States nearly 2.5 billion gallons of lubricants are manufactured; 1.4 % are automotive-related lubricants, and the rest are considered industrial lubricants. Therefore, the automotive engineer should become familiar with greases and oils and their characteristics as they relate to automotive use. Because this chapter deals with automotive lubricants, the emphasis will be placed on the use of vegetable oils within automotive systems. Furthermore, the chapter provides information on the chemistry of vegetable oils, the general performance requirement of lubricants and greases, standard test procedures required for the oil testing, and the issues of biodegradability and toxicity.
White Etching Crack Failure Mode in Roller Bearings: From Observation via Analysis to Understanding and an Industrial Solution
Authors: Luyckx Johan
Published: January 2013

Some roller bearing applications are prone to the white etching crack (WEC) failure mode. The applications seem to have in common that they work under dynamic operating conditions. The specific feature of this failure mode is that the subsurface microstructure of a failed bearing contains modified material structures near cracks which are white after a nital etching test. In case of a WEC failure, the real lifetime of the bearing is much lower than the theoretical lifetime calculation. The hypotheses of fatigue overload, hydrogen, and accumulated plastic microstrain are evaluated and a root cause hypothesis is developed based on observations. The white etching material structures are interpreted as adiabatic shear bands generated by an impact load mechanism. We developed the root cause hypothesis that the dynamic operation of a roller bearing is generating a bearing internal pressure peak causing loads at high strain rate which result in material damage and initiate the WEC failure mode. Impact tests reveal a high sensitivity of through hardened martensitic and bainitic bearing steels for the adiabatic shear band failure mode. The origin of the bearing internal pressure peak is further explained based on available ElastoHydrodynamic Lubrication (EHL) experimental and simulation results. The generation of butterflies and WEC networks is interpreted as recrystallisation driven by high stress after many load cycles or a moderate stress combined with a high strain rate loading. The industrial experience is analysed from the perspective of the root cause hypothesis. The Weibull curve of a WEC bearing failure case is explained based on the material parameter full width at half-maximum (FWHM) at the raceway surface. The potential solutions of an optimised microstructure, black oxidized treatment, and hot assembly are identified based on positive industrial experience.
Characterization of the Resistance of Protective Gloves to Pointed Blades
Authors: Dolez Patricia I. , Azaiez Mariem , Vu-Khanh Toan
Published: January 2013

Hand lacerations account for a large percentage of occupational injuries. Wearing appropriate protective gloves has been shown to reduce these risks. However, the case of pointed blades, which include knife tips, metal sharps, and a large number of cutting tools, is still largely unexplored and calls for more research. This paper presents some initial results of tests performed with glove materials and several types of pointed blades used as a puncture probe. Tested glove materials include uncoated and polymer-coated Kevlar and Dyneema knits, leather as well as sheets of neoprene, nitrile rubber, and polyurethane. The effect of various parameters such as blade reuse, sample thickness, blade tip angle, probe displacement rate, blade lubrication, and sample support on the resistance of these materials to pointed blades was studied. The results show that the maximum force appears to increase in a non-linear way with the thickness of the membrane. A decrease in puncture force with decreasing tip angle was observed with all materials. In addition, measurements carried out at displacement rates between 1 and 500 mm/min eventually reveal in some instances the possible existence of two puncture regimes. Finally, the contribution of both friction and sample deformation on the pointed blade puncture process is evidenced by the large effect of lubrication and sample support on the maximum force. However, no correlation appears to exist between resistance to pointed blades and resistance to cutting or puncture measured with standard test methods. This demonstrates the need for more research in that area and ultimately a dedicated standard test method.
Evaluation of Fire-resistant Clothing Using an Instrumented Mannequin: A Comparison of Exposure Test Conditions Set With a Cylinder Form or Mannequin Form
Authors: Ackerman M. Y. , Crown E. M. , Dale J. D. , Paskaluk S.
Published: January 2013

Setting up a manikin/burner system to evaluate FR clothing requires that the energy transfer to the surface of an instrumented manikin be measured and adjusted to meet the requirements of the test method being used (ASTM F1930 or ISO 11056). ISO 11056 makes provision for the use of an instrumented cylinder to initially set the physical position of burners before using the manikin. The idea behind the provision is that because of the symmetry of the cylinder the heat flux should be uniform over the surface enabling rapid initial setting of burner positions, fuel pressures, flow controls etc. This work experimentally evaluated the differences in heat flux that would be obtained if conditions were set with a cylinder and the cylinder then replaced with the manikin for. The work was undertaken as background to find out whether this procedure would be a useful addition to ASTM F1930. The study concluded that the additional cost/time associated with using a cylinder did not result in better exposure conditions on a manikin form primarily due to the non-uniform shape of the manikin.
Analysis of Physical and Thermal Comfort Properties of Chemical Protective Clothing
Authors: Wen ShuQin , Song Guowen , Duncan Scott
Published: January 2013

Research regarding chemical protective clothing (CPC) focuses on human comfort, clothing performance, and the heat strain associated with wearing protective materials. These studies are usually limited to one or two fabric/garment characteristics (e.g., garment weight, barrier permeability), and most of the research has been specific for certain tasks or garments. A systematic approach is needed in order to offer a comprehensive analysis on the performance of CPC and provide a technical basis for predicting comfort. This research measures the physical and thermal comfort related properties of CPC with available bench-scale methods and predicts the comfort level and heat strain based on the mechanical and physical properties of the material. Five articles of CPC and one fabric sample, with various chemical protective qualities, were evaluated with respect to mechanical and comfort related heat and moisture transfer properties. The results obtained were analyzed, and the physical burden and heat stress a human would experience when wearing these CPC fabrics were investigated. Comparisons and correlations between these properties and their contribution to clothing performance and human comfort are discussed. A full analysis of the physical and moisture related properties of the selected CPC fabrics is provided.