Relationship between ash content and R-70 self-heating rate of Callide Coal

Borecore samples from the Trap Gully pit at Callide have been assessed using the R-70 self-heating test. The highest R-70 self-heating rate value was 16.22 degrees C/h, which is consistent with the subbituminous rank of the coal. R-70 decreases significantly with increasing mineral matter content, as defined by the ash content of the coal. This effect is due to the mineral matter in the coal acting as a heat sink. A trendline equation has been fitted to the borecore data from the Trap Gully pit: R-70 = 0.0029 x ash(2) - 0.4889 x ash + 20.644, where all parameters are on a dry-basis. This relationship can be used to model the self-heating hazard of the pit, both vertically and laterally. (c) 2005 Elsevier B.V All rights reserved.

Effect of moisture content on the R-70 self-heating rate of Callide coal

Strip samples from the Boundary Hill pit at Callide have been tested in an adiabatic oven to assess the effect of moisture on the R-70 self-heating rate of coal. The two strip samples tested had R-70 self-heating rate values of 10.23 and 8.61 degrees C/h. As the moisture content of the coal was progressively increased, from the dry state of the test, the R-70 value decreased dramatically. At approximately 40-50% of the moisture holding capacity of the coal, the self-heating rate becomes measurable. Above this critical level of moisture content, the heat produced by oxidation is dissipated by moisture evaporation and coal self-heating is significantly delayed. (c) 2005 Elsevier B.V All rights reserved.

Comparison of the R-70 self-heating rate of New Zealand and Australian coals to Suggate rank parameter

Samples from New Zealand and Australia have been tested in an adiabatic oven to assess the effect of rank on the R-70 selfheating rate of coal. A non-linear relationship can be defined for coals from both countries using the revised Suggate rank (S-r) parameter. Subbituminous coals have the highest R-70 self-heating rate values, which are 20 times that of high volatile A bituminous coals on a dry mineral matter free basis (similar to 1 cf. 20 degrees C h(-1)). However, the moderating effects of moisture and mineral matter can reduce this difference to only 2-3 times for coal in-situ. (c) 2005 Elsevier B.V All rights reserved.

Identifying the energy gap: Magnitude and determinants of 5-year weight gain in midage women

Objective: The aims of this study were to estimate average yearly weight gain in midage women and to identify the determinants of weight gain and gaining weight at double the average rate. Research Methods and Procedures: The study sample comprised 8071 participants (45 to 55 years old) in the Australian Longitudinal Study on Women's Health who completed mailed surveys in 1996, 1998, and 2001. Results: On average, the women gained almost 0.5 kg per year [average 2.42 kg (95% confidence interval, 2.29 to 2.54) over 5 years]. In multivariate analyses, variables associated with energy balance (physical activity, sitting time, and energy intake), as well as quitting smoking, menopause/hysterectomy, and baseline BMI category were significantly associated with weight gain, but other behavioral and demographic characteristics were not. After adjustment for all of the other biological and behavioral variables, the odds of gaining weight at about twice the average rate (> 5 kg over 5 years) were highest for women who quit smoking (odds ratio = 2.94; 95% confidence interval, 2.17, 3.96). There were also independent relationships between the odds of gaining > 5 kg and lower levels of habitual physical activity, more time spent sitting, energy intake (but only in women with BMI > 25 at baseline), menopause transition, and hysterectomy. Discussion: The average weight gain equates with an energy imbalance of only about 10 kcal or 40 kJ per day, which suggests that small sustained changes in the modifiable behavioral variables could prevent further weight gain.

Nutritional status and energy expenditure in children pre-bone-marrow-transplant

The aims of this study were to establish the nutritional status of children pre- BMT and to determine whether predictive methods of assessing nutritional status and resting energy expenditure ( REE) are accurate in this population. We analysed the body cell mass ( BCM) ( n = 26) and REE ( n = 24) in children undergoing BMT. BCM was adjusted for height ( BCM/ HTp) and expressed as a Z score to represent nutritional status. To determine whether body mass index ( BMI) was indicative of nutritional status in children undergoing BMT, BMI Z scores were compared to the reference method of BCM/ HTp Z scores. Schofield predictive equations of basal metabolic rate ( BMR) were compared to measured REE to evaluate the accuracy of the predictive equations. The mean BCM/ HTp Z score for the subject population was -1.09 +/- 1.28. There was no significant relationship between BCM/ HTp Z score and BMI Z score ( r = 0.34; P > 0.05); however there was minimal difference between measured REE and predicted BMR ( bias = -11 +/- 149 kcal/ day). The results of this study demonstrate that children undergoing BMT may have suboptimal nutritional status and that BMI is not an accurate indication of nutritional status in this population. However, Schofield equations were found to be suitable for representing REE in children pre- BMT.

Interpretation of the temperature dependence of rate constants in biosensor studies

A comparison is made between Arrhenius and transition-state analyses of the temperature dependence of rate constants reported in four published biosensor studies. Although the Eyring transition-state theory seemingly affords a more definitive solution to the problem of characterizing the activation energetics, the analysis is equivocal because of inherent assumptions about reaction mechanism and the magnitude of the transmission coefficient. In view of those uncertainties it is suggested that a preferable course of action entails reversion to the empirical Arrhenius analysis with regard to the energy of activation and a preexponential factor. The former is essentially equivalent to the enthalpy of activation, whereas the magnitude of the latter indicates directly the extent of disparity between the frequency of product formation and the universal frequency factor (temperature multiplied by the ratio of the Boltzmann and Planck constants) and hence the likelihood of a more complicated kinetic mechanism than that encompassed by the Eyring transition-state theory. (C) 2004 Elsevier Inc. All rights reserved.

Interpretation of the temperature dependence of equilibrium and rate constants

The objective of this review is to draw attention to potential pitfalls in attempts to glean mechanistic information from the magnitudes of standard enthalpies and entropies derived from the temperature dependence of equilibrium and rate constants for protein interactions. Problems arise because the minimalist model that suffices to describe the energy differences between initial and final states usually comprises a set of linked equilibria, each of which is characterized by its own energetics. For example, because the overall standard enthalpy is a composite of those individual values, a positive magnitude for AHO can still arise despite all reactions within the subset being characterized by negative enthalpy changes: designation of the reaction as being entropy driven is thus equivocal. An experimenter must always bear in mind the fact that any mechanistic interpretation of the magnitudes of thermodynamic parameters refers to the reaction model rather than the experimental system For the same reason there is little point in subjecting the temperature dependence of rate constants for protein interactions to transition-state analysis. If comparisons with reported values of standard enthalpy and entropy of activation are needed, they are readily calculated from the empirical Arrhenius parameters. Copyright (c) 2006 John Wiley & Sons, Ltd.

Stoichiometric and kinetic characterisation of Nitrobacter in mixed culture by decoupling the growth and energy generation processes

The growth, maintenance and lysis processes of Nitrobacter were characterised. A Nitrobacter culture was enriched in a sequencing batch reactor (SBR). Fluorescent in situ hybridisation showed that Nitrobacter constituted 73% of the bacterial population. Batch tests were carried out to measure the oxygen uptake rate and/or nitrite consumption rate when both nitrite and CO2 were in excess, and in the absence of either of these two substrates. The results obtained, along with the SBR performance data, allowed the determination of the maintenance coefficient and in situ cell lysis rate of Nitrobacter. Nitrobacter spends a significant amount of energy for maintenance, which varies considerably with the specific growth rate. At maximum growth, Nitrobacter consume nitrite at a rate of 0.042 mgN/mgCOD(biomass)center dot h for maintenance purposes, which increases more than threefold to 0.143 mgN/mgCOD(biomass)center dot h in the absence of growth. In the SBR, where Nitrobacter grew at 40% of its maximum growth rate, a maintenance coefficient of 0.113 mgN/mgCOD center dot h was found, resulting in 42% of the total amount of nitrite being consumed for maintenance. The above three maintenance coefficient values obtained at different growth rates appear to support the maintenance model proposed in Pirt (1982). The in situ lysis rate of Nitrobacter was determined to be 0.07/day under aerobic conditions at 22 C and pH 7.3. Further, the maximum specific growth rate of Nitrobacter was estimated to be 0.02/h (0.48/day). The affinity constant of Nitrobacter with respect to nitrite was determined to be 1.50 mgNO(2)(-)-N/L, independent of the presence or absence of CO2. (c) 2006 Wiley Periodicals, Inc.

The inhibitory effects of free nitrous acid on the energy generation and growth processes of an enriched Nitrobacter culture

The inhibitory effects of nitrite (NO2-)/free nitrous acid (HNO2-FNA) on the metabolism of Nitrobacter were investigated using a method allowing the decoupling of the growth and energy generation processes. A lab-scale sequencing batch reactor was operated for the enrichment of a Nitrobacter culture. Fluorescent in situ hybridization (FISH) analysis showed that 73% of the bacterial population was Nitrobacter. Batch tests were carried out to assess the oxygen and nitrite consumption rates of the enriched culture at low and high nitrite levels, in the presence or absence of inorganic carbon. It was observed that in the absence of CO2, the Nitrobacter culture was able to oxidize nitrite at a rate that is 76% of that in the presence of CO2, with an oxygen consumption rate that is 85% of that measured in the presence of CO2. This enabled the impacts of nitrite/FNA on the catabolic and anabolic processes of Nitrobacter to be assessed separately. FNA rather than nitrite was likely the actual inhibitor to the Nitrobacter metabolism. It was revealed that FNA of up to 0.05 mg HNO2-N center dot L-1 (3.4 mu M), which was the highest FNA concentration used in this study, did not have any inhibitory effect on the catabolic processes of Nitrobacter. However, FNA initiated its inhibition to the anabolic processes of Nitrobacter at approximately 0.011 mg HNO2-N center dot L-1 (0.8 mu M), and completely stopped biomass synthesis at a concentration of approximately 0.023 mg HNO2-N center dot L-1 (1.6 mu M). The inhibitory effect could be described by an empirical inhibitory model proposed in this paper, but the underlying mechanisms remain to be revealed.

Stoichiometric and kinetic characterisation of Nitrosomonas sp in mixed culture by decoupling the growth and energy generation processes

A novel method that relies on the decoupling of the energy production and biosynthesis processes was used to characterise the maintenance, cell lysis and growth processes of Nitrosomonas sp. A Nitrosolnonas culture was enriched in a sequencing batch reactor (SBR) with ammonium as the sole energy source. Fluorescent in situ hybridization (FISH) showed that Nitrosomonas bound to the NEU probe constituted 82% of the bacterial population, while no other known ammonium or nitrite oxidizing bacteria were detected. Batch tests were carried out under conditions that both ammonium and CO, were in excess, and in the absence of one of these two substrates. The oxygen uptake rate and nitrite production rate were measured during these batch tests. The results obtained from these batch tests, along with the SBR performance data, allowed the determination of the maintenance coefficient and the in situ cell lysis rate, as well as the maximum specific growth rate of the Nitrosomonas culture. It is shown that, during normal growth, the Nitrosomonas culture spends approximately 65% of the energy generated for maintenance. The maintenance coefficient was determined to be 0.14 - 0.16 mgN mgCOD(biomass)(-1) h(-1), and was shown to be independent of the specific growth rate. The in situ lysis rate and the maximum specific growth rate of the Nitrosomonas culture were determined to be 0.26 and 1.0 day(-1) (0.043 h(-1)), respectively, under aerobic conditions at 30 degrees C and pH7. (c) 2006 Elsevier B.V. All rights reserved.

Heart rate variability characterization using a time-frequency based instantaneous frequency estimation technique

In this paper, a new method for characterizing the newborn heart rate variability (HRV) is proposed. The central of the method is the newly proposed technique for instantaneous frequency (IF) estimation specifically designed for nonstationary multicomponen signals such as HRV. The new method attempts to characterize the newborn HRV using features extracted from the time–frequency (TF) domain of the signal. These features comprise the IF, the instantaneous bandwidth (IB) and instantaneous energy (IE) of the different TF components of the HRV. Applied to the HRV of both normal and seizure suffering newborns, this method clearly reveals the locations of the spectral peaks and their time-varying nature. The total energy of HRV components, ET and ratio of energy concentrated in the low-frequency (LF) to that in high frequency (HF) components have been shown to be significant features in identifying the HRV of newborn with seizures.

Effect of a protein and energy dense n-3 fatty acid enriched oral supplement on loss of weight and lean tissue in cancer cachexia:A randomised double blind trial

Aim: N-3 fatty acids, especially eicosapentaenoic acid (EPA), may possess anticachectic properties. This trial compared a protein and energy dense supplement enriched with n-3 fatty acids and antioxidants (experimental: E) with an isocaloric isonitrogenous control supplement (C) for their effects on weight, lean body mass (LBM), dietary intake, and quality of life in cachectic patients with advanced pancreatic cancer. Methods: A total of 200 patients (95 E; 105 C) were randomised to consume two cans/day of the E or C supplement (480 ml, 620 kcal, 32 g protein ± 2.2 g EPA) for eight weeks in a multicentre, randomised, double blind trial. Results: At enrolment, patients' mean rate of weight loss was 3.3 kg/month. Intake of the supplements (E or C) was below the recommended dose (2 cans/day) and averaged 1.4 cans/day. Over eight weeks, patients in both groups stopped losing weight (Δweight E: -0.25 kg/month versus C: -0.37 kg/month; p=0.74) and LBM (ΔLBM E: +0.27 kg/month versus C: +0.12 kg/month; p=0.88) to an equal degree (change from baseline E and C, p<0.001). In view of evident non-compliance in both E and C groups, correlation analyses were undertaken to examine for potential dose-response relationships. E patients demonstrated significant correlations between their supplement intake and weight gain (r=0.50, p<0.001) and increase in LBM (r=0.33, p=0.036). Such correlations were not statistically significant in C patients. The relationship of supplement intake with change in LBM was significantly different between E and C patients (p=0.043). Increased plasma EPA levels in the E group were associated with weight and LBM gain (r=0.50, p<0.001; r=0.51, p=0.001). Weight gain was associated with improved quality of life (p<0.01) only in the E group. Conclusion: Intention to treat group comparisons indicated that at the mean dose taken, enrichment with n-3 fatty acids did not provide a therapeutic advantage and that both supplements were equally effective in arresting weight loss. Post hoc dose-response analysis suggests that if taken in sufficient quantity, only the n-3 fatty acid enriched energy and protein dense supplement results in net gain of weight, lean tissue, and improved quality of life. Further trials are required to examine the potential role of n-3 enriched supplements in the treatment of cancer cachexia.

The study of ultra-low energy deposition of hydrogenated amorphous carbon thin films

This thesis is dedicated to the production and analysis of thin hydrogenated amorphous carbon films. A cascaded arc plasma source was used to produce a high density plasma of hydrocarbon radicals that deposited on a substrate at ultra low energies. The work was intended to create a better understanding of the mechanisms responsible for the film formation, by an extensive analysis on the properties of the films in correlation with the conditions used in the plasma cell. Two different precursors were used: methane and acetylene. They revealed a very different picture for the mechanism of film formation and properties. Methane was less successful, and the films formed were soft, with poor adhesion to the substrate and decomposing with time. Acetylene was the better option, and the films formed in this case were harder, with better adhesion to the substrate and stable over time. The plasma parameters could be varied to change the character of films, from polymer-like to diamond-like carbon. Films deposited from methane were grown at low deposition rates, which increased with the increase in process pressure and source power and decreased with the increase in substrate temperature and in hydrogen fraction in the carrier gas. The films had similar hydrogen content, sp3 fractions, average roughness (Ra) and low hardness. Above a deposition temperature of 350°C graphitization occurred - an increase in the sp2 fraction. A deposition mechanism was proposed, based upon the reaction product of the dissociative recombination of CH4+. There were small differences between the chemistries in the plasma at low and high precursor flow rates and low and high substrate temperatures; all experimental conditions led to formation of films that were either polymer-like, soft amorphous hydrogenated carbon or graphitic-like in structure. Films deposited from acetylene were grown at much higher deposition rates on different substrates (silicon, glass and plastics). The film quality increased noticeably with the increase of relative acetylene to argon flow rate, up to a certain value, where saturation occurred. With the increase in substrate temperature and the lowering of the acetylene injection ring position further improvements in film quality were achieved. The deposition process was scaled up to large area (5 x 5 cm) substrates in the later stages of the project. A deposition mechanism was proposed, based upon the reaction products of the dissociative recombination of C2H2 +. There were large differences between the chemistry in the plasma at low and medium/high precursor flow rates. This corresponded to large differences in film properties from low to medium flow rates, when films changed their character from polymer-like to diamond-like, whereas the differences between films deposited at medium and high precursor flow rates were small. Modelling of the film growth on silicon substrates was initiated and it explained the formation of sp2 and sp3 bonds at these very low energies. However, further improvements to the model are needed.