Heat of adsorption and critical temperature studies of boundary lubricants on steel surfaces

The study of heat of desorption on sliding steel surfaces under boundary lubrication gave an optimum surface roughness value at which the total heat is minimum. This value is both quantitatively and qualitatively analysed and identified as heat of desorption of molecules of additives from the base oil on to the steel surface and the activation energy of the interface material due to dislocation movement.It is shown that the change in entropy (ΔS) of the boundary lubricant is a controlling factor for effective lubrication. Limiting value of coverage for a particular value of change in entropy is necessary to prevent scuffing of steel surfaces. The study also reveals that a minimum value of concentration of polar additives is necessary for effective boundary lubrication. These results help to elucidate the mechanism of scuffing of the steel surfaces.     

Strategies for preserving the confidentiality of psychological reports.

Describes strategies that appear to be effective in reducing breaches of confidentiality due to unauthorized dissemination of psychological reports. Strategies suggested include (1) clarifying the word "confidentiality," (2) not placing psychological reports in general medical records, and (3) insisting that forms authorizing release of information specifically name the psychology department or an individual staff member. It is concluded that operationally defining in the report itself how the report is to be treated is a complementary strategy that may help reduce breaches of confidentiality. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Respiratory failure in acute pancreatitis: the role of free fatty acids

Hypertriglyceridemia has been noted in patients with acute pancreatitis and respiratory failure. Utilizing an isolated, perfused, canine pulmonary lobe, the effect of triglyceride infusion on pulmonary function was evaluated. When heparin was used to anticoagulate the perfusion circuit, the addition of triglyceride to the autologous blood perfusate resulted in massive weight gain (226 gm), intrapulmonary shunting (36%), and a marked drop in pulmonary compliance (congruent to 50%). Heparin activates lipoprotein lipase, and therefore some triglyceride in the perfusate was lipolyzed with a resultant increase in serum free fatty acids (FFAs) to 253 mumole/dl. When anticoagulation of the perfusion circuit was accomplished by defibrinogenation with Arvin, the addition of triglyceride to the autologous blood perfusate caused minimal weight gain (28 gm), no intrapulmonary shunting, and only a slight decrease in pulmonary compliance (22%). Arvin has no effect on lipoprotein lipase, and the FFA level in the perfusate remained normal (less than 70 mumole/dl). Thus it appears that FFA release secondary to the action of pulmonary lipoprotein lipase on blood triglyceride is the important pathogenic step in the induction of respiratory failure in this model.     

Effects of poor solvents on radical-radical termination of polymerization

It is shown that in poor solvents for the polymer the rate coefficient for radical-radical termination in the polymerization of styrene and methyl methacrylate is diminished compared with that in bulk monomer. It is suggested that this effect is due to the formation of tightly coiled macroradicals which hinder the radical-radical reaction process.     

A comparison of lead isotope ratios in the bark pockets and annual rings of two beech trees collected in Derbyshire and South Yorkshire, UK

ICP-MS analysis of the bark pockets and annual rings of two beech (Fagus sylvatica L.) trees collected from Longshaw, Derbyshire and Swinton, South Yorkshire in the UK recorded differences in the (206)Pb/(207)Pb isotope ratio. In the Longshaw sample, the (206)Pb/(207)Pb isotope ratio of the bark pockets ( approximately 1914-1998, 78-260 microg g(-1) Pb) declined from approximately 1.16 to 1.12, whilst the annual rings (1899-1998, 0.2-2.5 microg g(-1) Pb) had a (206)Pb/(207)Pb ratio of approximately 1.18. In the Swinton sample, the bark pockets (approximately 1919-1998, 7-78 microg g(-1) Pb) declined from 1.15 to 1.11 and the annual rings (1899-1998, 0.2-0.5 microg g(-1) Pb) from 1.18 to 1.15. The data implied that the bark pockets accumulated lead directly from the atmosphere through wet and dry deposition, whilst the annual rings accumulated lead from the soil via the roots. The bark pockets recorded a relative decline in the accumulation of lead from indigenous sources, such as lead smelting and coal combustion (1.17-1.19), and increase in imported sources such as the smelting of Australian ores (1.04) and leaded petrol usage (1.06-1.09). In contrast, the annual rings at Longshaw recorded ratios typical of indigenous lead, whilst the annual rings in Swinton recorded a relatively small decrease in (206)Pb/(207)Pb reflecting leaded petrol usage. The decline in (206)Pb/(207)Pb of the bark pockets was consistent with the historical decline in (206)Pb/(207)Pb of atmospheric lead recorded in peat, lake sediments and archival herbage at other UK locations.     

Addition of sec-butyllithium to m-diisopropenylbenzene

The reaction of equivalent quantities of sec-butyllithium with m-diisopropenylbenzene in cyclohexane and benzene solution in the presence and absence of catalytic amounts of triethylamine, does not yield the diadduct quantitatively. Oligomer formation occurs to varying extents depending on the reaction conditions, and, contrary to claims in the literature, this may not be a good route to a difunctional initiator for anionic polymerization.     

Terpenoids as major precursors of dissolved organic matter in landfill leachates,surface water,and groundwater

13C NMR analyses of hydrophobic dissolved organic matter (DOM) fractions isolated from a landfill leachate contaminated groundwater near Norman, OK; the Colorado River aqueduct near Los Angeles, CA; Anaheim Lake, an infiltration basin for the Santa Ana River in Orange County, CA; and groundwater from the Tomago Sand Beds, near Sydney, Australia, found branched methyl groups and quaternary aliphatic carbon structures that are indicative of terpenoid hydrocarbon precursors. Significant amounts of lignin precursors, commonly postulated to be the major source of DOM, were found only in trace quantities by thermochemolysis/gas chromatography/mass spectrometry of the Norman Landfill and Tomago Sand Bed hydrophobic DOM fractions. Electrospray/tandem mass spectrometry of the Tomago Sand Bed hydrophobic acid DOM found an ion series differing by 14 daltons, which is indicative of aliphatic and aryl-aliphatic polycarboxylic acids. The product obtained from ozonation of the resin acid, abietic acid, gave a similar ion series. Terpenoid precursors of DOM are postulated to be derived from resin acid paper sizing agents in the Norman Landfill, algal and bacterial terpenoids in the Colorado River and Anaheim Lake, and terrestrial plant terpenoids in the Tomago Sand Beds.     

The crash reduction effectiveness of a network-wide traffic police deployment system

Random Road Watch (RRW) is a traffic policing program in operation in Queensland, Australia. It differs from conventional traffic policing in that an explicit resource management technique is used which randomly schedules low levels of police enforcement in a manner intended to provide long-term, widespread coverage of a road network and hence maximise road safety benefits. Implementation of the program studied in Queensland covered 55% of total crashes within the state. This study aimed to measure the crash effects of the RRW program in Queensland. A quasi-experimental study design was used for the evaluation incorporating Poisson regression statistical analysis techniques. Analysis of the effects of the Queensland RRW program on crash frequency has shown the program to be effective overall. Estimated program effects were largest on fatal crashes, with an estimated reduction of 31%. Estimated aggregate program crash effects reduced with crash severity and increased with time after program introduction. Crash reductions in the third year after program introduction translated into savings, at state level, of some 12% of the state's crashes of all severities and some 15% of the state's fatal road crashes. Overall, the program produced a significant 11% reduction in total crashes in areas outside of metropolitan Brisbane. The opportunity-cost benefit/cost ratio for the program was estimated to be 55:1.     

SR-30 turbojet engine real-time sensor health monitoring using neural networks,and Bayesian belief networks

This paper describes the use of artificial intelligence-based techniques for detecting and isolating sensor failures in a turbojet engine. Specifically, three artificial intelligence (AI) techniques are employed: artificial neural networks (NNs), statistical expectations, and Bayesian belief networks (BBNs). These techniques are combined into an overall system that is capable of distinguishing between sensor failure and engine failure—a critical capability in the operation of turbojet engines. The turbojet engine used in this study is an SR-30 developed by Turbine Technologies. Initially, NNs were designed and trained to recognize sensor failure in the engine. The increased random noise output from failing sensors was used as the key indicator. Next, a Bayesian statistical method was used to recognize sensor failure based on the bias error occurring in the sensors. Finally, a BBN was developed to interpret the results of the NN and statistical evaluations. The BBN determines whether single or multiple sensor failures signify engine failure, or whether sensor failures represent separate, unrelated incidences. The BBN algorithm is also used to distinguish between bias and noise errors on sensors used to monitor turbojet performance. The overall system is demonstrated to work equally well during start-up and main-stage operation of the engine. Results show that the method can efficiently detect and isolate single or multiple sensor failures within this dynamic environment.     

Aerosol and Precipitation Chemistry at a Remote Himalayan Site in Nepal

As a part of a year long aerosol measurement program in the Nepal Himalayas, a series of 12 h samples of aerosol and event-based samples of precipitation were collected in postmonsoon, 1996; premonsoon, 1997; and monsoon, 1997. Results show that diurnal variations in the regional valley wind system are responsible for variations in the major ion (Na + , NH 4 + , K + , Mg 2+ , Ca 2+ , Cl - , NO 3 - , and SO 4 -2 ) concentrations in the aerosol. On time scales greater than a day, changes in atmospheric circulation and associated changes in the precipitation regime have an important effect on aerosol ion concentrations. Periods of high major ion concentration in the aerosol generally coincide with similar periods in precipitation chemistry, although a linear relationship between concentrations in these 2 media is not robust due to limited data. High scavenging ratio values are found for all species except SO 4 2- . Nitrate, Cl - , and NH 4 + are enriched in the precipitation compared to the aerosol, implying the presence of gaseous acidic species (HNO 3 and HCl) and gaseous NH 3 in the air. Ammonium was also enriched with respect to SO 4 2- in aerosol during a dry episode in the monsoon season. This may represent relatively local sources of NH 3 (from neighboring villages) and was not scavenged due to the lack of precipitation. Empirical orthogonal function (EOF) analysis clearly shows the presence of 2 dominant pollutant transport mechanisms for the premonsoon and monsoon seasons (i.e., valley wind system and monsoon circulation). Although physically different, these 2 transport mechanisms follow similar transport pathways and transport aerosol into the Himalayas from similar source regions. Further, EOF analysis suggests a southerly maritime signal in the aerosol during monsoon and a more distant westerly maritime signal during premonsoon. Our results support the potential for using glaciochemical records from the Himalayas to investigate variations in the strength of past monsoon circulation and westerly disturbances.