bluuebunny/crossref_metadata_2025 huggingface dataset:
“Small Cities Blues:” Looking for Growth Factors in Small and Medium-Sized Cities
Authors: Erickcek George A. , McKinney Hannah
Published: July 2006

The purpose of this exploratory study is an attempt to identify public policies that have the potential to increase the economic viability of smaller metropolitan areas and cities. The authors identify characteristics associated with smaller metro areas that performed better than expected (winners) and worse than expected (losers) during the 1990s. The authors then look for evidence that public policy choices may have enhanced a metro area' ability to succeed by examining whether winners and losers are qualitatively different in ways that may indicate consequences of policy choices. A cluster analysis is completed to group the metro areas based on changes in social, economic, and demographic variables during the 1990s. The authors then use contingency table analysis and ANOVA to see if winners and losers are related to the grouping of metro areas in a way that may indicate the presence of government policy.
Peace Process in Sri Lanka
Authors: Wickremesinghe Ranil
Published: July 2006

The December 2001 general elections in Sri Lanka provided the government a clear mandate to bring about a negotiated political solution to the conflict, while safeguarding the country's territorial integrity. The Ceasefire Agreement with the Liberation Tigers of Tamil Eelam (LTTE) in February 2002 facilitated a substantive dialogue on a range of issues. A series of well-structured meetings throughout 2002 and 2003 sought to address issues of devolution of power to Muslims of the Eastern Provinces. The ‘Triple R’ programme—Relief, Rehabilitation and Reconciliation—was initiated in the districts of the North and East. Future progress of the peace process will have to take account of the commitment of the government and the LTTE to evolve a solution based on a federal structure within a united Sri Lanka. Fears in the South that a federal solution will lead to the disintegration of Sri Lanka must be addressed. The peace process and the final settlement in the future will need to safeguard the rights of Muslim and Sinhala minorities in the North East.
Labour Organization and Economical Aspects within On-farm Diversifying Households
Authors: Pascotto Sabrina
Published: July 2006

Business diversification represents an ongoing process which is being progressively adopted by small-medium farms, especially in disadvantaged, rural and mountainous areas. As such it may represent a tool for their development, as long as farmers are able to exploit its potential and find proper organizational solutions that best fit their farm features.

In this article, a stratified sample of diversifying farms is analysed in order to provide some evidence on the influence of diversification on role organization among all the on-farm ‘active’ subjects and on the working time allocation within different activities, depending on farm type, economic size and type of diversification pathways undertaken. Moreover, the comparison between the proportion of time engaged in alternative activities and that of the relative returns deriving from them allows to understand the efficiency of this strategy. The final aim is the comprehension of the extent to which the diversification ratio is making its way in the farmers’ business conceptions and the individuation of obstacles and stimula preventing or promoting the further development of this option.
Politicize or Perish! The Importance of Policy for Australian Psychiatric–Mental Health Nurses
Authors: Sgro Silvana , Happell Brenda
Published: July 2006

As the largest professional group within the Australian mental health nursing workforce, psychiatric-mental health nurses are well positioned to influence mental health policy. However, the dominance of nursing by the medical profession has limited the extent to which this potential has been realized, with nurses remaining relatively unheard within the political arena. In recognition of this situation, the Centre for Psychiatric Nursing Research and Practice implemented a position for a policy analyst. Three primary aims were identified for this position: networking and relationship building, building profile, and providing a voice for psychiatric-mental health nursing. This article provides an overview of these three aims and the achievements to date. It is concluded that the policy analyst position has made a significant contribution to increasing the profile of psychiatric-mental health nursing and, therefore, to its capacity to influence policy.
Expression profiling of clonal lymphocyte cell cultures from Rett syndrome patients
Authors: Delgado Ivan J , Kim Dong Sun , Thatcher Karen N , LaSalle Janine M , Van den Veyver Ignatia B
Published: July 2006

Background

More than 85% of Rett syndrome (RTT) patients have heterozygous mutations in the X-linked MECP2 gene which encodes methyl-CpG-binding protein 2, a transcriptional repressor that binds methylated CpG sites. Because MECP2 is subject to X chromosome inactivation (XCI), girls with RTT express either the wild type or mutant MECP2 in each of their cells. To test the hypothesis that MECP2 mutations result in genome-wide transcriptional deregulation and identify its target genes in a system that circumvents the functional mosaicism resulting from XCI, we performed gene expression profiling of pure populations of untransformed T-lymphocytes that express either a mutant or a wild-type allele.

Methods

Single T lymphocytes from a patient with a c.473C>T (p.T158M) mutation and one with a c.1308-1309delTC mutation were subcloned and subjected to short term culture. Gene expression profiles of wild-type and mutant clones were compared by oligonucleotide expression microarray analysis.

Results

Expression profiling yielded 44 upregulated genes and 77 downregulated genes. We compared this gene list with expression profiles of independent microarray experiments in cells and tissues of RTT patients and mouse models with Mecp2 mutations. These comparisons identified a candidate MeCP2 target gene, SPOCK1, downregulated in two independent microarray experiments, but its expression was not altered by quantitative RT-PCR analysis on brain tissues from a RTT mouse model.

Conclusion

Initial expression profiling from T-cell clones of RTT patients identified a list of potential MeCP2 target genes. Further detailed analysis and comparison to independent microarray experiments did not confirm significantly altered expression of most candidate genes. These results are consistent with other reported data.
The effect of different combination therapies on oxidative stress markers in HIV infected patients in cameroon
Authors: Ngondi Judith L , Oben Julius , Forkah David Musoro , Etame Lucten Honore , Mbanya Dora
Published: July 2006

The study assessed the effect of some highly active antiretroviral therapies (HAART), used in the management of HIV/AIDS in Cameroon, on oxidative stress markers such as malondialdehyde (as TBARs), albumin, protein carbonyl content and protein sulfhydryls groups. 85 HIV positive patients (34.8 ± 9.3 years) were on three different highly active antiretroviral therapies (HAART patients). 65 HIV positive patients (32.2 ± 10.9 years) on no treatment (Pre-HAART patients), and 90 non-HIV infected patients (32.6 ± 9.3 years), were the control groups. Plasma TBARs as well as carbonyl levels were significantly higher in HIV patients on HAART compared to pre-HAART patients or non-HIV infected controls. On the other hand, the protein sulfhydryl group content was not different for patients on HAART compared to pre-HAART patients, but both were significantly lower than non-HIV infected controls (P < 0.0001, 0.001). The combination treatment Therapy I [stavudin (80 mg) + Lamivudin (600 mg) + Nevirapin + (400 mg) zidovudin (600 mg)] brought about a significant (p < 0.05) reduction in the plasma concentration of protein sulfhydrl groups as well as TBARs compared to Therapy II [stavudin (80 mg) + Lamivudin (300 mg) + nevirapin (400 mg)] or with combination Therapy III of [zidovudine (600 mg) + lamivudin(300 mg) with efavirenz (600 mg)] (P < 0.05). The content of the antioxidant, Vitamin C was lower in the plasma of patients on Therapy I compared to those on Therapy II (P < 0.01) and Therapy III (P < 0.001).

HIV infection therefore increases the oxidative stress process, while antiretroviral combination therapy increased protein oxidation as well as the level of oxidative stress already present in HIV infection.
Dabska tumor (Endovascular papillary angioendothelioma) of testis: a case report with brief review of literature
Authors: Bhatia Alka , Nada Ritambra , Kumar Yashwant , Menon Prema
Published: July 2006

The Dabska tumor also known as Endovascular papillary angioendothelioma is a rare type of hemangioendothelioma characterized by intraluminal papillary endothelial structures. Most of these are superficial in location but occurrence in deeper tissues is also known. We describe case report of testicular Dabska tumor in a child presenting as inguinal hernia. To the best of our knowledge this is the first case report describing the occurrence of this rare entity in testis.
Accuracy of Deception Judgments
Authors: Bond Charles F. , DePaulo Bella M.
Published: July 2006

We analyze the accuracy of deception judgments, synthesizing research results from 206 documents and 24,483 judges. In relevant studies, people attempt to discriminate lies from truths in real time with no special aids or training. In these circumstances, people achieve an average of 54% correct lie-truth judgments, correctly classifying 47% of lies as deceptive and 61% of truths as nondeceptive. Relative to cross-judge differences in accuracy, mean lie-truth discrimination abilities are nontrivial, with a mean accuracy d of roughly .40. This produces an effect that is at roughly the 60th percentile in size, relative to others that have been meta-analyzed by social psychologists. Alternative indexes of lie-truth discrimination accuracy correlate highly with percentage correct, and rates of lie detection vary little from study to study. Our meta-analyses reveal that people are more accurate in judging audible than visible lies, that people appear deceptive when motivated to be believed, and that individuals regard their interaction partners as honest. We propose that people judge others' deceptions more harshly than their own and that this double standard in evaluating deceit can explain much of the accumulated literature.
Dispositional Optimism and Coping: A Meta-Analytic Review
Authors: Nes Lise Solberg , Segerstrom Suzanne C.
Published: July 2006

The relation between dispositional optimism and better adjustment to diverse stressors may be attributable to optimism's effects on coping strategies. A meta-analytic review ( K = 50, N = 11,629) examined the impact of dispositional optimism on coping. Dispositional optimism was found to be positively associated with approach coping strategies aiming to eliminate, reduce, or manage stressors or emotions ( r = .17), and negatively associated with avoidance coping strategies seeking to ignore, avoid, or withdraw from stressors or emotions ( r = -.21). Effect sizes were larger for the distinction between approach and avoidance coping strategies than for that between problem and emotion-focused coping. Meta-analytic findings also indicate that optimists may adjust their coping strategies to meet the demands of the stressors at hand, and that the optimism-coping relationship is strongest in English-speaking samples.
Being Seen As Individuals Versus As Group Members: Extending Research on Metaperception to Intergroup Contexts
Authors: Frey Frances E. , Tropp Linda R.
Published: July 2006

Recent research has begun to examine people's expectations for how they are viewed in intergroup contexts, yet little work has considered how these metaperceptions relate to those that emerge in interpersonal contexts. As we extend research on metaperceptions into the intergroup realm, we must address several important conceptual issues. In this article, we provide a general overview of research on interpersonal metaperceptions, along with many factors that are likely to affect whether people think they are viewed as individuals or as group members. We also consider how metaperceptions are likely to be formed differently in interpersonal and intergroup contexts, and depending on the group membership of the perceiver We then explore the consequences of different kinds of metaperceptions for intergroup relations, and how they relate to strategies we might use to improve intergroup relations, to suggest future directions for research on metaperceptions in intergroup contexts.
NEW FINDING OF THREE KINDS OF GLASSY STATE POR CYCLOHEXENE AS A SINGLE COMPOUND
Authors: Haida Osamu , Suga Hiroshi , Seki Syûzô
Published: July 2006

Three kinds of glassy state of cyclohexene were discovered. Two of them are of crystalline phase, and were prepared in situ in calorimeter cell by different thermal treatments. These Tg values were 81 K (crystal-I) and 83 K (crystal-II), respectively. The glassy liquid was also prepared by vapor condensation method, its Tg being 78 K (DTA-value).
Voltage‐programming method with transimpedance‐feedback technique for threshold voltage and mobility compensations in large‐area high‐resolution AMOLED displays
Authors: In Hai‐Jung , Kwag Pyong‐Su , Kang Jin‐Sung , Kwon Oh‐Kyong , Chung Ho‐Kyoon
Published: July 2006

Abstract— A voltage‐programming method with transimpedance‐feedback control technique is proposed for compensating threshold voltage and mobility variations of driving thin‐film transistors (TFTs) in large‐area high‐resolution polycrystalline‐silicon (poly‐Si) active‐matrix organic light‐emitting‐diode (AMOLED) displays. Those electrical characteristic variations of TFTs throughout a large‐area high‐resolution panel result in picture‐quality non‐uniformity of AMOLED displays. The simulation and experimental results of the proposed method show that the maximum emission‐current error for 30‐in. full‐high‐definition television (HDTV) applications is less than 1.9% when the mobility variation and the threshold‐voltage variation are ±12.5% and ±0.3 V, respectively. The proposed method is the best programming method for large‐area high‐resolution AMOLEDs among the published methods.
Properties of column spacers on a flexible color filter using a roll‐to‐roll process
Authors: Sonehara A. , Eguchi T. , Sugizaki A. , Kumano A. , Ito T. , Takahashi T.
Published: July 2006

Abstract— Column spacers were manufactured by a roll‐to‐roll process for a flexible plastic substrate and an LCD prototype was demonstrated for the first time. The purpose of this paper is to obtain a stable cell gap for plastic LCDs by designing the column spacers. The optimum condition was derived for the properties of the column spacers parameters, such as the cross section, density, and hardness. As a result, we could determine the optimum elastic modulus of the column spacers needed in order to precisely maintain the cell gap of the LCD as well as that of conventional glass plates, resulting in a uniform display luminance.
2‐D/3‐D switchable displays
Authors: Willemsen O. H. , De Zwart S. T. , Hiddink M. G. H. , Willemsen Oscar
Published: July 2006

Abstract—In this paper, the design of a lenticular‐based 2‐D/3‐D display for mobile applications is described. This display combines look‐around capability with good 3‐D resolution. In order to allow high‐resolution datagraphic applications, a concept based on actively switched lenses has been developed. A very noticeable problem for such displays is the occurrence of dark bands. Despite slanting the lenticular and defocusing the lens, banding becomes unacceptable when the display is viewed from an angle. As a solution, fractional viewing systems to reduce the banding intensity by almost two orders of magnitude is introduced. The resulting 3‐D display can be viewed from any horizontal direction without banding.
Sand-Production Simulation in Heavy-Oil Reservoirs
Authors: Zhang Liangwen , Dusseault Maurice B.
Published: July 2006

A new sand-production model is developed based on interparticle contact-force variations at the discrete micromechanical level, scaled up to the macroscopic level. Two mechanisms for sand production are expected in the field: dynamic detachment (plucking of particles) and equilibrium yield (shear dilation followed by liquefaction at ~50% porosity). The model discussed in this paper describes the sand-production mechanism in the dynamic detachment process. Within the new model formulation, sand production arises because of either a large porosity gradient or a large pressure gradient. The 1D steady-state solution of the new model is also presented; it may be used for simple sensitivity analysis for parameters such as field stress and pressure-depletion effect.
Nanometer-scale displacement sensing using self-mixing interferometry with a correlation-based signal processing technique
Authors: Hast J. , Okkonen M. , Heikkinen H. , Krehut L. , Myllylä R.
Published: July 2006

A self-mixing interferometer is proposed to measure nanometre-scale optical path length changes in the interferometer’s external cavity. As light source, the developed technique uses a blue emitting GaN laser diode. An external reflector, a silicon mirror, driven by a piezo nanopositioner is used to produce an interference signal which is detected with the monitor photodiode of the laser diode. Changing the optical path length of the external cavity introduces a phase difference to the interference signal. This phase difference is detected using a signal processing algorithm based on Pearson’s correlation coefficient and cubic spline interpolation techniques. The results show that the average deviation between the measured and actual displacements of the silicon mirror is 3.1 nm in the 0–110 nm displacement range. Moreover, the measured displacements follow linearly the actual displacement of the silicon mirror. Finally, the paper considers the effects produced by the temperature and current stability of the laser diode as well as dispersion effects in the external cavity of the interferometer. These reduce the sensor’s measurement accuracy especially in long-term measurements.
Refrigeration oils for use with non‐CFC, non‐ozone‐depleting refrigerants — key performance and retrofitting issues
Authors: Johnston G. J. , Shim J. , Brechot P. D.
Published: July 2006

This paper compares the performance of polyol ester base fluids — in key areas such as miscibility, stability, transport property, and antiwear protection — with other candidate oils proposed for use with HFC‐134a and with naphthenic oils conventionally employed with ozone‐depleting CFC refrigerants such as CFC‐12. The data demonstrate that properly selected polyol ester‐based fluids meet key lubricant requirements for use with ‘ozone friendly’ refrigerant HFC‐134a. In addition, the paper describes key issues in retrofitting existing CF C/naphthenic oil‐based systems to run with HFC‐134a and polyol ester.
High‐temperature vapour‐phase lubrication
Authors: Rao Arvind M. N.
Published: July 2006

Although it is recognised that the move towards cleaner burning, higher efficiency engines requires operating temperatures in excess of 500°C, there are currently few practical means available to achieve this. Therefore, the development of cleaner, more efficient engines requires the use of new lubrication technologies. Any potential lubricant and lubrication technology must address the changing needs of the original equipment manufacturers (OEMs). Specifically, this should include material and fuel compatibility, increased lubrication performance at elevated temperatures and pressures, ashless deposits, reduced particulate emissions, and biodegradability. Over the past six years, various organisations have addressed many of these needs and have successfully demonstrated the use of phosphate esters as candidate vapour phase (VP) lubricants. With the correct choice of lubricant, VP lubrication has been effective in reducing friction and minimising wear of ferrous‐rich stainless and tool steels, alloys, ceramics and composites, at temperatures up to 670°C, under both sliding and rolling contact. This paper details the development of VP lubrication, and of sers some insights into materials and lubricant selection, and some examples of successful applications.
A study of the tribological behaviour of heterocyclic derivatives as additives in rape seed oil and mineral oil
Authors: Huang W. J. , Wu X. H. , Zeng Y.
Published: July 2006

The tribological properties of two novel heterocyclic derivatives as additives in rape seed oil and in mineral oil were investigated using a four‐ball machine. The morphologies and chemical features of the worn steel surfaces were observed and examined by means of X‐ray photoelectron spectroscopy and scanning electron microscopy. Both heterocyclic compounds improved the load‐carrying and extreme‐pressure capacities and the friction‐reducing and antiwear properties of rape seed oil more than they improved those of the mineral oil. Surface analyses of the rubbed surfaces revealed the formation of a protective film containing FeSO4, organosulphur compound, FeS2, polymerised ester, and organonitrogen compound when the surfaces were lubricated by rape seed oil containing the additives. The protective film formed during sliding processes contributed to the increase in the wear resistance.
Mathematical model for the thickening power of viscosity index improvers: Application to engine oil formulations
Authors: Bourgognon H. , Rodes C. , Neveu C. , Huby F.
Published: July 2006

It is essential for a lubricating oil blender to be able to quantify the contribution that each component entering in a formulation makes to the viscosity of the finished product. In this context several studies have been devoted to the modelling of the thickening power of different types of polymers at both high (100 °C and 40°C) and low (−15°C) temperature in base oils of various origins and viscosities. To complement these earlier investigations, it is necessary to quantify the effect of the additive package on the viscosity of the formulation. For this purpose, the effect of several DI packages of different performance levels has been investigated in order to derive appropriate mathematical models representing the contribution of these packages to oil viscosity.
A study of the influence of lanthanum fluoride on the tribological properties of bonded solid film lubricants and its mechanism of function
Authors: Feng B. , Zhao J. Z. , Nie M. D. , Dang H. X.
Published: July 2006

The influence of lanthanum fluoride (LaF3) on the characteristics of phenolepoxy‐bonded MoS2 dry films was investigated. The functional mechanism was specifically studied using several analytical means. The results showed that the wear life of dry films containing a certain amount of LaF3 was considerably increased over that of the films without LaF3. However, the effect of LaF3 on the friction coefficient of the dry films was shown to be negligible. It was found that the addition of LaF3 is effective in reducing the oxidation tendency of MoS2 in the films during the friction process. The reason for this is investigated by the authors.
Future directions of fundamental research in additive tribochemistry
Authors: Wei Dan‐Ping
Published: July 2006

This paper reviews briefly the present state of fundamental research, in tribochemistry of load‐carrying additives, including oiliness agents, organolsulphur, organochlorine, organophosphorus, organic borates and organometallic compounds. The emphasis is on the weak areas of investigation. It is revealed that the least understood mechanisms, such as the effect of additives on fretting wear, additive‐material compatibility, the efficacy of antifatigue additives and the action of water‐based fluid additives in metalworking, are the concern of overlapping spheres of learning. A cooperative effort by chemists, metallurgists and mechanical engineers would help overcome the difficulties posed by problems in areas beyond individual expertises. Some research projects for the future are also suggested.
Tribochemistry in ceramic lubrication
Authors: Qunji Xue , Jianjum Weii
Published: July 2006

Effective lubrication systems are crucial to the successful application of ceramic materials in many advanced technologies. A review is given here of the tribochemistry of ceramic lubrication, including the effects of water, water‐based lubricants, hydrocarbons, additives and solid lubricants, on the friction and wear properties of ceramics, the tribochemical mechanisms of ceramics with lubricants and the wear mechanisms of ceramics. Finally, some suggestions about further study of ceramic lubrication are offered.
The antiwear and extreme pressure action mechanism of CeF3 in grease
Authors: Yafeng Lain , Qunji Xue , Xushou Zhang
Published: July 2006

Cerium (III) fluoride as an antiwear or extreme pressure additive has been used in grease and bonded solid film lubricant, but its action mechanism has not been clarified. In this paper, the tribological characteristics of lithium grease containing CeF3, CaF2, SbF3, CeO2 and graphite fluoride ((CF)n) were evaluated with an SRV tester. The results show that pastes containing CaF2 and (CF)n give good antiwear and anti‐friction performance, but do not possess extreme pressure properties. Adding CeO2 to grease offers no benefit to the antiwear and anti‐friction performance of the paste. Paste containing SbF3 has poor lubricating properties. XPS analysis shows that the good antiwear and extreme pressure properties of paste containing CeF3 can be attributable to the formation of a physically adherent film and a chemical reaction film on the rubbing surface. Thermogravimetry shows that CeF3 acts as an agent for the slow release of the fluorine element.
Extracted waxes from a lubricant oil base stock and their relation to composition and flow properties
Authors: Khan H. U. , Sikora A. , Nautiyal S. P. , Anwar M. , Agrawal K. M.
Published: July 2006

The phase transition temperatures and associated enthalpies of extracted waxes from an IN range lubricant oil base stock and its fractions in the boiling range 247–546°C, were determined by DSC. X‐ray diffractograms of these samples, showing the variation in intensity with angle 2θ at 5°C and 24°C, were also obtained. The thermal parameters of the extracted waxes were correlated with the composition and flow properties of the base oil sample. The crystallisation behaviour of these waxes conforms to the hydrocarbon type component analysis of the base stock and its fractions, obtained by mass spectroscopy. The key n‐alkanes present in the extracted waxes, and that would be necessary in tailoring a suitable pour‐point depressant for the base oil, have also been predicted.
The assessment of ZnDTP tribochemical reactivity by electrochemical simulation
Authors: Ozimina Dariusz
Published: July 2006

This paper presents the results of experiments on zinc dithio‐phosphate (ZnDTP) tribochemical reactivity with the surface of 100Cr6 bearing steel using an electrochemical simulation method. The paper presents some basic assumptions used in electrochemical simulation of antifriction additive reactivity on metal surfaces, and some observations on the individual character of the initial layer formation and its effect upon the subsequently formed layers.

ZnDTP reactivity with a non‐reacting gold surface was used as a reference. The in situ formation of boundary layers is demonstrated using electrochemical scanning tunnelling microscopy (ESTM). This shows the changes taking place in surface topography during the formation of the surface layers.

On the basis of these experiments, important information was obtained about ZnDTP reactivity with metal surfaces and is presented here.
Role of alkyl moieties in the antiwear and antioxidant performance of alkyl phosphorodithioates
Authors: Sharma M. , Bansal V. , Ray S. S. , Sarin R. , Tuli D. K. , Bhatnagar A. K.
Published: July 2006

Phosphorodithioate derivatives having different alkyl substitu‐ents have been synthesised, while keeping the core phosphorus‐sulphur moiety intact. The change in antiwear, extreme‐pressure, and antioxidant properties with the variation in sub‐stituents at oxygen and at sulphur linkages in the phosphorodithioates has been studied. The role of the heteroatoms with regard to the alkyl substituents has been examined. The experimental data show that the chemical structure of an additive influences its physicochemical and tribological properties.
The tribochemical performance of nano/micrometre borate modified by an N‐containing compound as an oil additive
Authors: Qiao Yulin , Liu Weimin , Xu Binshi , Ma Shining , Xue Qunji
Published: July 2006

An N‐modified nano / micrometre borate (MNMB) as an oil additive was synthesised by an ultrasonic dispersion and emulsion reaction in the microemulsion phase. The particles of the MNMB additive were between 20 and 500 nm in diameter. The tribological properties of the MNMB as an oil additive were investigated using a four‐ball tester. The results reveal that the MNMB possesses good tribological properties. When the boron concentration is 0. 05 wt. %, the wear‐scar diameter is smallest and the seizure load is highest. The antiwear and extreme‐pressure properties of the MNMB were best at a viscosity of 65. 3 mms2. Small‐area X‐ray photoelectron spectroscopy (XPS) and electron probe microanalysis (EPMA) indicate that the MNMB additive can form a tribological mixed reaction film containing C, O, B, N, and Na on a rubbing surface. The elemental boron exists in four different chemical states, but is mainly present in the form of BN on the rubbing surface.
Molecular spectroscopic studies of the effect of base oils on additive—additive interactions
Authors: Sarpal A. S. , Bansal V. , Sastry M. I. S. , Mukherjee S. , Kapur G. S.
Published: July 2006

The effect of different types of base oil of API Groups I to V, such as mineral based (solvent refined, hydrofinished, hydro‐cracked/ wax isomerised) and synthetic based (polyalphaolefin and ester), on the interaction of zinc dialkyldithiophosphate (ZDDP) with polyisobutylene succinimide (PIBS) has been studied by variable‐temperature (VT) IR and 31P NMR spectro‐scopic techniques. Since ZDDPs are known to exist in monomeric and polymeric forms and as neutral and basic salts, and their functioning is temperature dependent, the structural changes observed in the NMR and IR spectra of the ZDDP—PIBS system in different base oils have been addressed with this in mind. The strength and composition of ZDDP—PIBS complexes has been explained in terms of the degree of solvation provided by the medium (base oil) in which they are present, and thermodynamic parameters ΔH and ΔS estimated from the VT IR spectra. The results indicate that the complexes are stronger and stable in polar base oils, such as from Groups I and V. The equilibrium shifts towards the neutral form of ZDDP in polar base oils. The results have been substantiated by correlating the variation in the shift and width of IR and 31P NMR signals to the stability of the complexes and low values of ΔH and ΔS. Polar solvents, such as methanol and tetrahydro‐furan, also favour the formation of the neutral form of ZDDP and stronger complexes between PIBS and ZDDP, in a manner similar to that observed for polar base oils.
Parametric elastohydrodynamic study of a linear contact applied to SiC lubricated with a low‐viscosity fluid
Authors: Francisco A. , Blouin A. , Frěne J.
Published: July 2006

Ceramic materials are often used in tribological applications because of their good mechanical properties. Silicon carbide (SiC) has a low density, high Young's modulus, high corrosion resistance, and very low friction in water. It is a very good candidate for replacing waterproof oil‐lubricated bearings in water pumps and for applications when water is used as a lubricant. In such applications the SiC dissolves very slowly in water to form silicilic acid. After running in, journal and bearing surfaces look like mirrors with very low roughness and very small friction coefficient.

This paper reports on a parametric study to model the cylinder—plane configuration, which is then utilised in the specific case of SiC in water. The study was carried out in order to reduce the number of parameters and to ensure good precision of the results. The numerical model is applied to an SiC contact with a very low‐viscosity lubricant (water) using elastohydrodynamic (EHD) conditions. Multigrid techniques for the Reynolds equation and multilevel, multi‐integration methods for the elasticity equations are used to solve the EHD problem. These results are given in non‐dimensional form using the Moes parameters M and L for several velocities and loads. Comparison is made between the two‐ and three‐dimensional cases in order to assess the effects for the cylinder ends.
Micro‐mechanism of initiation of sliding
Authors: Kato Koji , Kanno Seiichiro
Published: July 2006

In order to understand the effects of contact shape and sliding direction on tangential coefficient a VTR (Video Tape Recorder) computer system has been developed to visualise the micro‐slip distribution at the contact interface, during the process of micro displacement, before macro sliding.

It is shown that micro‐slip distribution is strongly affected by the shape of the contact area and the sliding direction, which gives a good explanation of the observed relationships between tangential coefficient (defined as tangential force divided by normal load) and tangential displacement.

It is suggested, as a result, that the VTR‐computer system developed in this study allows useful observation and understanding of the micro‐mechanism of initiation of macro sliding.
Comparison of two stick‐slip testers and recommendations for repeatable and significant stick‐slip testing
Authors: Van de Velde F. , De Baets P. , Van Geeteruyen C.
Published: July 2006

Because of the interaction of the large number of parameters influencing stick‐slip, it is very difficult to perform repeatable and reproducible tests that define the anti‐stick‐slip properties of lubricants. In order better to understand the difficulties encountered in stick‐slip testing, an overview of the influencing parameters, with a discussion of each parameter, is given in this paper.

Some modifications of the reciprocating stick‐slip tester that was used in the ASTM test procedure before the latter was withdrawn, in order to improve the repeatability of its test results, are discussed. The significance of the results is checked by comparison with a rotary stick‐slip tester.

Finally, recommendations for correct stick‐slip testing and interpretation of stick‐slip results are presented.
Technical note the triboelectrochemical cell: A new apparatus for tribocorrosion studies
Authors: Takadoum J.
Published: July 2006

This technical note gives details of a new testing for looking at tribocorrosion, a joint mechanical/electrochemical process, allowing evaluation of the joint action of corrosion and wear. The new apparatus, called a ‘triboelectrochemical cell’, is demonstrated in use, and some results are given for nickel, tested in H2SO4 solution.
The effect of abradant particle comminution on the intensity of three‐body abrasion
Authors: Scieszka S. F. , Jadi A. S. M.
Published: July 2006

An attempt has been made to understand why testing involving abradant particles leads to inconsistent results, despite identical test conditions. The work undertaken involved experiments on a rubber wheel abrasion tester (RWAT), and found comminution of the abradant to be the omitted factor: careful examination of the abradant particles after each test revealed that, even for the lowest load, the particles did not remain unbroken. The results obtained showed that at least part of the variation between tests carried out under nominally identical conditions can therefore be ascribed to ignoring the effects of size reduction. The paper concludes by recommending some changes in standard procedure.
New field and engine test data to demonstrate the wear protection benefits of a unique boundary chemistry (UBC)
Authors: Shaub Hal , Leggett Ken , Pandosh John , Perrin Keith , Searle Anne , Sprague Stan
Published: July 2006

The wear protection performance of unique boundary chemistry (UBC), both while in the engine and after removal, was tested with reference to commercial API SG, API SH/ILSAC GF‐1, and API SJ/ILSAC GF‐2 quality oils in two 80,450 km field tests, in modified and standard sequence tests, and in radiotracer engine studies.

The radiotracer tests of UBC added to an API SJ/ILSAC GF‐2 quality oil replicated previously published results of wear reductions achieved in a comparison of an API SH/ILSAC GF‐1 oil with and without UBC.

In extended Sequence IIIE runs, two engines, each lubricated with the same API SH/ILSAC GF‐1 oil, were unable to complete the tests as a result of excessive oil consumption due to hot stuck rings. In contrast, two Sequence IIIE engines lubricated with the same API SH/ILSAC GF‐1 oil treated with UBC completed the extended test without incident, even though the UBC‐treated API SH/ILSAC GF‐1 oil replaced the API SH/ILSAC GF‐1 oil for the first oil drain interval only.

A fully formulated SAE 5W–30 oil, which contained a full complement of UBC (20%), met all the requirements of API SH/ILSAC GF‐1 quality and gave very low average and maximum cam and cam plus lifter wear on standard ASTM Sequence VE and IIIE tests. The same API SH/ILSAC GF‐1 oil without UBC gave somewhat higher wear on both tests, but both oils met API SH/ILSAC GF‐1 requirements.

Wear metals analysis of a field test of 36 taxicabs, which compared an API SJ/ILSAC GF‐2 quality oil to the same oil treated with UBC for the first drain interval, and also to a UBC‐treated oil at every oil change, showed a reduction in the rate of used oil Fe accumulation for both methods of UBC treatment. This test also revealed a striking impact on Fe levels from Si found in used oil samples during an episode of Si contamination in local gasoline supplies.

Finally, in a field test of 10 taxicabs, with parts measured before and after testing, wear reductions were observed in rings and bearings in UBC‐treated cabs compared to those with API SG oil alone.
The identification and evaluation of natural and synthetic esters in mineral oils
Authors: Bondioli Paolo , Piero Sabarino G.
Published: July 2006

The use of mineral‐based lubricating oils blended with vegetable oils or their derivatives has raised the question of the detection, identification, and quantitative evaluation of these substances in formulated products. This paper addresses the problem in a systematic way, and suggests some possible solutions by means of analytical pathways using column chromatography, GLC, and HPLC techniques. The methods suggested allow the identification and evaluation of fatty acid esters with mono‐ and polyalcohols.
The impact of detergent chemistry on TBN retention
Authors: van Dam W. , Broderick D. H. , Freerks R. L. , Small V. R. , Willis W. W.
Published: July 2006

Historically, the characterisation of fresh and used diesel engine lubricants has been based on a limited number of analytical techniques. One of the most important methods of analysis has been total base number (TBN) measurement. Although TBN measurements are informative, easy, and quick, it can be misleading to base the judgement of an oil's performance solely on one criterion.

This paper offers some observations from a field test, showing that some detergent types gave unacceptable performance even though the TBNs were at an acceptable level. It is hypothesised that some detergents do not effectively neutralise all acidic species present in the lubricant, thereby reserving their own base, while in fact the oil may no longer provide sufficient protection against bearing corrosion. This hypothesis is supported by bench and engine test data. It is recommended that, at a minimum, total acid number (TAN) measurements be included in any analysis, and where time and cost permit, wear metals content, oxidation, soot content, and viscosity should also be evaluated.
Tribology of SiC/SiC Ceramic Matrix Composites in Liquid Oxygen in Relation to the Design of Hydrostatic Bearings
Authors: Bozet J. L. , Nélis M. , Leuchs M. , Bickel M.
Published: July 2006

This paper reports on the characterisation of ceramic matrix composites (CMCs) for bearing applications in liquid oxygen (LOX). Compatibility tests were performed to determine the safety and feasibility of subsequent research operations. Tribological tests were then made on a pin‐on‐disc apparatus using LOX as the working environment. The measurement of friction and wear allowed a comparison between different kinds of CMCs and 440C steel materials. As a logical progression a real geometry test rig is now being built. The design of a hybrid journal bearing has been finished and the manufacturing of the rig components started.
Evaluation Tests of Industrial Vacuum Bearings for Space Use
Authors: Obara S. , Sasaki A. , Haraguchi M. , Imagawa K. , Kawashima N. , Nishimura M.
Published: July 2006

The tribological performance of industrial vacuum bearings for space use was experimentally evaluated. The bearings selected for investigation were an 8 mm bore deep‐groove ball bearing lubricated with a sputtered MoS2 film and one lubricated with an ion‐plated Ag film, commercially available from three Japanese bearing manufacturers. Based on survey results of tribological requirements for existing satellite mechanisms, four types of bearing tests were defined and conducted: a vacuum test at room temperature, an atmosphere resistance test, a thermal vacuum test, and a vibration test. In addition to these tests, the variation in the tribological performance of the industrial bearings was also investigated. The results of more than 80 tests demonstrated that the industrial vacuum bearings had sufficient lubrication lives with low frictional torque and the data were reasonably repeatable, indicating a potential for space use.
Modelling Combustion Engine Degradation Processes
Authors: Stodola Jiří
Published: July 2006

This paper looks at combustion engine wear processes, including the categorisation of wear products (adhesive, abrasive, spherical, laminar, fatigue, corrosive, non‐ferrous, and other particles), and the evaluation of the trends in wear processes resulting from deterministic balance equations dealing with the processes of production and removal of wear products in combustion engine lubrication systems. The practical application of this approach to engine‐lubricant system wear has been quantified for a statistically significant set of data for engines with potential for friction coefficient reduction, with selective verification. The actual technical condition of the combustion engine has been evaluated by a multidimensional statistical evaluation. The model allows the qualitative description by means of a number of quantifiable variables (tribological, ecological, or economical parameters of the engine‐lubricant system).
Peripherally Inserted Central Venous Catheters Are Not Superior to Central Venous Catheters in the Acute Care of Surgical Patients on the Ward
Authors: Turcotte Simon , Dubé Serge , Beauchamp Gilles
Published: July 2006

Background

Peripherally inserted central venous catheters (PICC) have supplanted central venous catheters (CVC) for the administration of intravenous antibiotics and total parenteral nutrition to patients in our hospital. From the literature, it appears that this change has occurred in a number of other surgical units. Accounting for the change are the expected advantages of low complication rates at insertion, prolonged use without complications and interruption, and cost‐ and time‐savings.

Methods

We have proceeded with a review of the literature to understand and justify this change in practice. Our hypothesis was that the routine adoption of PICC instead of CVC for the acute care of surgical patients has occurred in the absence of strong scientific evidence. Our aim was to compare the associated infectious, thrombotic, phlebitic, and other common complications, as well as PICC and CVC durability. Articles concerning various aspects of PICC‐ and CVC‐related complications in the acute care of adult patients were selected from the literature. Studies were excluded when they primarily addressed the use of long‐term catheters, outpatient care, and pediatric patients. Data were extracted from 48 papers published between 1979 and 2004.

Results

Our results show that infectious complications do not significantly differ between PICC and CVC. Thrombotic complications appear to be more significant with PICC and to occur early after catheterization. Phlebitic complications accounted for premature catheter removal in approximately 6% of PICC. Finally, prospective data suggest that approximately 40% of PICC will have to be removed before completion of therapy, possibly more often and earlier than CVC.

Conclusions

We believe that there is no clear evidence that PICC is superior to CVC in acute care settings. Each approach offers its own advantages and a different profile of complications. Therefore, the choice of central venous access should be individualized for surgical patients on the ward. More comparative prospective studies are needed to document the advantages of PICC over CVC.
Biliary Cystadenoma and Other Complicated Cystic Lesions of The Liver: Diagnostic and Therapeutic Challenges
Authors: Teoh Anthony Y.B. , Ng Simon S.M. , Lee K.F. , Lai Paul B.S.
Published: July 2006

Introduction

Biliary cystadenomas are complicated cystic lesions of the liver. They are rare and pose considerable diagnostic and therapeutic challenges.

Methods

We present our experience managing these lesions by performing a retrospective review of all patients with a preoperative diagnosis of or histologically proven biliary cystadenoma who underwent surgery between January 1995 and January 2005 at our institution. Altogether, 20 patients (16 women, 4 men) with a mean age of 58 years underwent a total of 22 operations. The diagnosis of biliary cystadenoma was based on exclusion of other pathologic entities and the presence of radiologic characteristics of biliary cystadenoma. Abdominal ultrasonography (US), computed tomography, or both were performed in all patients. US‐guided fine‐needle aspiration cytology was performed in seven patients and all of them were negative for malignancy. A preoperative diagnosis of biliary cystadenoma was made in 16 patients based on clinical and radiologic features and was correct in 6 of them. Diagnosis of biliary cystadenoma was not suspected in four patients.

Results

The overall diagnostic accuracy was 30%. Enucleation was the most common surgical procedure and was performed in 10 patients. The mean follow‐up period was 5.5 ± 2.8 years. No recurrence was detected in patients with confirmed biliary cystadenoma after adequate excision.

Conclusions

The findings of this study highlight the difficulty with preoperative diagnosis of biliary cystadenoma, which has seldom been discussed in the literature. Preoperative differentiation by means of radiologic imaging is inaccurate (30%). Any therapy short of complete excision leads to local recurrence and risk of malignant transformation. Complete excision of any suspicious lesion remains the best method of diagnosis and treatment.