Modeling Wear Traces of Automotive Friction Materials by Cantor Set

Grooves parallel to the disc rotation direction were observed on the surface of non-metallic organic (NMO) friction materials after Friction Assessment Screening Test (FAST). Grooves are traces of wear and formed by abrasive mechanism. Grooves have fractal nature and they can be described by Cantor set. Two equations, one is time coordinate (x-axis) “matheqn” and the other one is wear ordinate (y-axis) “matheqn”, were proposed based on Cantor set to model the linear relationships among wear, time and sliding speed.     

Effect of NiO on the Phase Stability and Microstructure of Yttria-Stabilized Zirconia

Nickel oxide (NiO) was screen printed onto the surfaces of 3 and 8 mol% yttria-stabilized zirconia (YSZ) dense pre-fired substrates and then heat treated at temperatures from 1350° to 1550°C. The effect of NiO was dependent on the yttria content of the substrate. In 3 mol% YSZ, it was found to alter the phase composition from predominantly tetragonal with a small amount of cubic phase to one consisting of approximately equal amounts of cubic and monoclinic phase. The cubic grains were much larger than the monoclinic ones and contained more nickel. Furthermore, nickel was observed to migrate through the thickness of the tile, a distance of approximately 200 μm. In the 8 mol% YSZ substrates, the phase composition was unaltered, although large grains developed under the printed NiO layer and the nickel migration was confined to the extent of these large grains.     

Chromate leaching from inhibited primers: Part I. Characterisation of leaching

Leaching and characterisation studies have been undertaken on two chromate-inhibited epoxy polyamide primers. Leaching was carried out in 5% (w/v) NaCl solutions at different pH values (1, 3, 5 and 7) and the amount of Cr released into solution was monitored over time. Cr release was initially high, but as the immersion time increased the leaching from the primers slowed. Prior to and after immersion, the primers were characterised by a number of techniques including electron microprobe analysis, X-ray microdiffraction, Raman spectroscopy, and positron annihilation lifetime spectroscopy. The unexposed primers were found to contain the inorganic phases SrCrO₄, BaSO₄ and TiO₂ (anatase or rutile). Upon immersion, water uptake by the primers was observed, together with a decrease in the amount of SrCrO₄ in the primers. These studies provide insights into the mechanism of chromate leaching from inhibited primers.     

The Virtual Architecture of Silicon Valley

Over the past half-century, as Silicon Valley has emerged as the Mecca of digital technology, the buildings of the area have remained resolutely bland, superficial, and ephemeral. This may in fact signal not mere cheapness but also an alternative aesthetic, as yet unarticulated: a self-conscious aversion to architectural representations of hierarchy, stability, and technological permanence. Tracing the history as well as present trends of design and research and development in Silicon Valley, this article suggests a challenge as well as an opportunity for architects, but only if they are willing to put aside some of the profession's fundamental premises.     

Informal care and economic appraisal: a discussion of possible methodological approaches

The role played by informal carers in the care of people with chronic disabilities is well known. Given its importance, it is essential to consider the evaluation methodology applied in economic appraisals of different care options. Few studies attempt any evaluation and those that do use varied, inconsistent and controversial methodologies. This paper aims to elicit the major issues and methodological problems related to economic appraisal of informal care. The main concern over the present methods utilized is the lack of explicit exploration of the benefits, as perceived by carers. Carers, through their decision to care it is argued, will consider both costs and benefits. Although concepts encompassed by benefits tend to be less tangible they may considerably outweigh any financial burdens. Various methods have been utilized in the past. Financial outlays are fairly straightforwardly costed, personal effort on the part of carers causes more problems. Methods applied include: the cost of substitute services; state benefits; and travel time values. The most useful is probably the latter, although it is not problem-free. Assessing benefits relating to concepts of direct and indirect utility and welfare is more complex and difficult to measure. Despite considerable literature on carers' attitudes, often these concepts are not applied (especially to residential care options) or if they are, negative aspects are emphasized (with domiciliary care). A useful application of economic appraisal would elicit optimal solutions to care dilemmas. Producing economic burden information about informal care may not be particularly constructive. Brief assessment of eight scenarios of care, considering cost differences for the public sector and the preferences of patient and carer gives insight to the problem. It emphasizes the complexity of the issue and the essential role likely to be placed on care managers in helping carers to maximize the net benefit of their efforts.     

Time-action characteristics of regular and NPH insulin in insulin-treated diabetics

The time course of action of regular and NPH insulins injected sc was studied in 15 insulin-treated diabetics over a 24-h period during which they received a constant infusion of glucose. The blood glucose began to decline in 1.2 +/- 0.1 h (range, 0.5--2) and reached its nadir in 5.7 +/- 0.3 h (range, 4--8) after the sc injection of regular insulin. The peak effect of regular insulin usually persisted for several hours, and the total duration of action was 16.2 +/- 1.1 h (range, 9--24). Both the time of peak effect and the total duration of action were considerably prolonged compared to data provided in standard textbooks. Free insulin increased to a peak in 2.7 +/- 0.3 h (range, 1--4) after regular insulin injection and then returned to baseline by 8.8 +/- 0.96 h. Subcutaneous injection of NPH insulin decreased the blood glucose by 2.4 +/- 0.5 h (range, 1--7), with a maximal effect at 11.0 +/- 1.4 h (range, 5--19). The total duration of effect on blood glucose was 25.1 +/- 0.7 h (range, 20--29). These values are similar to those in standard textbooks. Although the total insulin levels increased after the injection of NPH insulin, there was very little if any elevation in free insulin. Recognition of the prolonged effect of regular insulin is important in establishing an insulin treatment regime for diabetic patients.     

The usefulness of cerebrospinal fluid tests for neurosyphilis

To determine the usefulness of cerebrospinal fluid (CSF) tests for syphilis at a large academic hospital, clinical and laboratory data on 644 patients in whom such testing was requested over a 12-month period were analysed. In 198 cases (31%) the Treponema pallidum haemagglutination (TPHA) screening test could not be performed because of insufficient fluid. Thirty-eight of the remaining patients were diagnosed as having active neurosyphilis. Examination of 22 files of patients who had a positive TPHA and fluorescent treponemal antibody absorption (FTA-Abs) test together with a negative CSF Venereal Disease Research Laboratory (VDRL) test revealed that other CSF measures indicating disease activity (CSF protein, cells or IgG index) were not utilised optimally. In 10 (45%) of these patients neurosyphilis was not diagnosed despite either abnormal or incomplete CSF biochemical analysis, indicating that if the CSF VDRL is used as the sole marker for disease activity, some cases of neurosyphilis are likely to be missed.     

A regulatory role for recombinase activating genes, RAG-1 and RAG-2, in T cell development

Effects of etoposide (VP-16) and cytosine arabinoside (Ara-C) on the cell cycle of HL-60 and THP-1 cells were studied by flow cytometry using the bromodeoxyuridine (BrdU)/DNA assay technique to investigate the efficacy of VP-16 for monocytic leukemia cells. VP-16 inhibited the proliferation of THP-1 cells more strongly than that of HL-60 cells at any concentrations used at 24 and 48 hr. VP-16 arrested HL-60 and THP-1 cells in the G2/M phase and reduced them in the G0/G1 and early S phase at higher concentrations. There was no significant difference in the percentage of G2/M phase cells at the same concentration between both cells. However, reduction in the G0/G1 and early S phase cells was more marked in THP-1 than HL-60 cells significantly. On the other hand, Ara-C perturbed the cell cycle of HL-60 cells more than that of THP-1 cells at 24 and 48 hr. These results suggest that the effects of VP-16 on the cell cycle may be more intense in THP-1 than HL-60 cells, and support the efficacy of VP-16 for treating monocytic leukemia in vivo.     

Evaluation of the developmental toxicity of methacrylonitrile in Sprague-Dawley rats and New Zealand white rabbits

Timed-pregnant Sprague-Dawley (CD) outbred rats and New Zealand White rabbits were dosed by gavage with methacrylonitrile (MACR) in distilled water during major organogenesis. Rats were dosed on Gestational Days (GD) 6 through 15 (0, 5, 25, or 50 mg MACR/kg/day) and rabbits on GD 6 through 19 (0, 1, 3, or 5 mg MACR/kg/day). Maternal clinical status was monitored daily during treatment. At termination (GD 20, rats; GD 30, rabbits), confirmed-pregnant females (25-26 per group, rats; 17-22 per group, rabbits) were evaluated for clinical status and gestational outcome; each live fetus was examined for external, visceral, and skeletal malformations. In rats, no treatment-related maternal clinical signs or mortality were observed, nor was there any adverse effect on maternal body weight or food or water consumption. At necropsy, absolute, relative, and adjusted maternal liver weight was increased at the mid- and high-dose groups, an effect that may be indicative of induction of hepatic enzymes rather than toxicity. In the absence of any indication of maternal toxicity, the no-observed-adverse-effect level (NOAEL) for maternal toxicity in this study was >/=50 mg MACR/kg/day. The NOAEL for developmental toxicity in rats was also >/=50 mg MACR/kg/day. There was no effect of treatment on postimplantation loss, mean fetal body weight per litter, or morphological development. In rabbits, maternal mortality and clinical signs were not dose related. Maternal food consumption, body weight, and liver weight were not adversely affected by treatment. Thus, the maternal NOAEL was >/=5 mg MACR/kg/day. Maternal toxicity, including death, was observed >/=7.5 mg/kg/day in preliminary studies. The developmental NOAEL was also >/=5 mg MACR/kg/day. There was no adverse effect of treatment on postimplantation loss or fetal body weight. A significant decrease in the percentage male fetuses per litter was observed, although there was no effect on total live litter size, suggesting that the reduction in the ratio of live male fetuses in the high-dose group was not biologically significant. MACR had no adverse effect on morphological development. In summary, oral administration of MACR to rats and rabbits during organogenesis, at doses that did not cause persistent maternal toxicity (50 mg MACR/kg/day, rats; 5 mg MACR/kg/day, rabbits), also did not cause any adverse developmental effects.