Structural Characterization of the New Fullerene-Rare Gas Compound Ar1C60

Abstract

We communicate how C₆₀ Hot Isostatically Pressed (HIPed) at 200° or 400°C with a pressure of 1.7 kbar of Ar produces the new fullerene-rare gas compound Ar₁C₆₀. We have shown, using Xray powder diffraction and subsequent Rietveld analysis, that this solid can be characterised stoichiometrically as Ar₁C_60- The stoichiometry has also been confirmed by thermal gravimetric analysis (TGA) showing 5% by weight to be Ar (expected=5.25%). The presence of Ar is confirmed by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). This material is found to be remarkably stable to loss of Ar over several weeks at room temperature. This represents the first full characterisation of an interstitial rare gas fullerene compound.

     

THE INFLUENCE OF MOISTURE ON THE COMBUSTION OF WOOD

A new three-dimensional (3-D) field model for enclosure fire growth has been developed by CSIRO and UNSW, Australia. The model includes the coupling of gas-phase combustion and the pyrolysis of wood. It has been used to predict the flame spread and fire development in a room witha rear timber wall and a propane burner. A parametric study of the effects of the moisture content of the timber on the flame spread and development of the fire in a room is described. The computed results compare satisfactorily with measurements from a fire test carefully conducted in a room.     

透水性路面砖路面可实现水的循环利用——初期成效及远景

透水性路面砖路面可作为贮存中水的设施,以降低自来水的需求压力.屋面汇集的雨水可贮存在路面下,并可用作低品质要求的家庭供水的来源,如浇灌花园及冲洗厕所.由于地下水在夏季或干旱地区可能供不应求,因此,地下水的蒸发量对保证有足够的供应量产生巨大影响.为此,进行了一系列旨在控制地下水水分蒸发的试验.试验中,水被贮存于各种不同路面砖路面体系内,包括采用或不采用土工布,或是采用各种不同类型土工布的路面结构.试验发现,一种双层土工布(其中一层具有透水性、并可减少污染物下渗,而另一层则能控制水分蒸发)在减少水分蒸发量方面,比不用土工布或仅用一层隔断油污的土工布都要好.在现场还进行了另一种类似的试验,不过路面贮存的水量因下雨而不断补充加入,从而使整个试验体系中始终充满水,试验结果同样表明,双层土工布在防止水分蒸发方面性能最佳.本文力图通过试验结果求得路面贮存水量的理论值,以便正确地确定需要多大的贮存空间;此外,在选用新型土工布时,测定其渗滤率及水质状况也是非常重要的.     

Effect of first-dimension undersampling on effective peak capacity in comprehensive two-dimensional separations

The objective of this work is to establish a means of correcting the theoretical maximum peak capacity of comprehensive two-dimensional (2D) separations to account for the deleterious effect of undersampling first-dimension peaks. Simulations of comprehensive 2D separations of hundreds of randomly distributed sample constituents were carried out, and 2D statistical overlap theory was used to calculate an effective first-dimension peak width based on the number of observed peaks in the simulated separations. The distinguishing feature of this work is the determination of the effective first-dimension peak width using the number of observed peaks in the entire 2D separation as the defining metric of performance. We find that the ratio of the average effective first-dimension peak width after sampling to its width prior to sampling (defined as ) is a simple function of the ratio of the first-dimension sampling time (t(s)) to the first-dimension peak standard deviation prior to sampling (1sigma): = square root1+0.21(t /(s)(1) sigma(2) This is valid for 2D separations of constituents having either randomly distributed or weakly correlated retention times, over the range of 0.2 on t(s)/1 sigma from this expression is in qualitative agreement with previous work based on the effect of undersampling on the effective width of a single first-dimension peak, but predicts up to 35% more broadening of first-dimension peaks than is predicted by previous models. This simple expression and accurate estimation of the effect of undersampling first-dimension peaks should be very useful in making realistic corrections to theoretical 2D peak capacities, and in guiding the optimization of 2D separations.     

High diffraction efficiency from one- and two-dimensional Nyquist frequency binary-phase gratings

We examine the diffraction properties of one- and two-dimensional binary-phase gratings encoded onto pixelated liquid crystal displays (LCDs). We find that the first-order diffracted intensity from these binary-phase patterns can reach 100% of the zero-order intensity when the period of the grating approaches the Nyquist limit of the LCD. Experimental results show excellent agreement with theoretical predictions. This is a surprising result that has a number of implications for the encoding of diffractive optical elements.     

The Effect of Melt Extrusion Process Parameters on Rotary‐Evaporated Poly(propylene) Nanocomposites

Design of experiments is employed to investigate the interrelationships between processing and nanotube surface chemistry on the properties of PP nanocomposites. Statistically significant effects of nanomaterial type and concentration, extrusion temperature, screw speed, and recirculation time, and their interactions, on nanocomposite thermal properties and stability are isolated. The effects of these factors on the shear storage modulus, the low‐frequency slope of the shear storage modulus, decomposition temperature, and melt temperature are explored. Nanotube concentration has the most significant effect in enhancing the decomposition temperature of the nanocomposite, while long extrusion time and higher temperatures lead to deteriorated properties.

     

The Effectiveness of Antibrowning Dip Treatments to Reduce After‐Cooking Darkening in Potatoes

Abstract: After‐cooking darkening (ACD) is an inherent and undesirable trait that develops in cooked potatoes. The objective of this study was to evaluate the effectiveness of sodium acid sulfate (SAS) dip treatments compared to other antigraying treatments and a control to reduce ACD in boiled, Katahdin potatoes. Dip treatments were applied for 3 min prior to boiling and included: 3% SAS, 3% citric acid (CA), 3% sodium acid pyrophosphate (SAPP), along with a distilled water control. SAS‐ and CA‐treated potatoes had slightly, but significantly (P ≤ 0.05) higher b* and chroma values, which indicates a more intense yellow potato color, with less graying, compared to the control. SAS‐ and CA‐treated potatoes also had significantly (P≤ 0.001) lower pH values for inner and outer potato surfaces than the control. No significant (P > 0.05) differences were detected for total phenolic or mineral contents among treatments. CA and SAPP samples had slightly, but significantly (P≤ 0.05) higher moisture contents than the control. Sensory test results showed no significant differences for color, aftertaste, or overall acceptability. However, CA‐treated samples were rated significantly (P≤ 0.05) lower for flavor than all other treatments and panelists commented on sour notes. CA‐ and SAS‐treated potatoes were scored slightly, but significantly lower for texture than other treatments due to a waxy outer layer. However, SAS was the most acidic dip treatment, but did not significantly affect flavor. Overall, results suggest that SAS was similarly accepted by consumers in comparison to CA and SAPP, which is the industry standard to reduce ACD. Practical Application: After‐cooking darkening (ACD) is an undesirable potato trait that occurs after potatoes have been processed. Sodium acid pyrophosphate (SAPP) has been used as the industry standard to reduce ACD. Sodium acid sulfate (SAS) treatments prior to boiling appeared to be comparable to SAPP and citric acid in effectiveness to reduce ACD. SAS did not negatively affect the flavor of boiled potato samples according to sensory results. The SAS treatment may be more beneficial for potatoes intended for potato salad products.     

The impact of anti-tobacco industry prevention messages in tobacco producing regions: evidence from the US truth campaign

Background: Adolescents who live in tobacco producing regions may not respond favourably to anti-industry ads. Objective: To examine whether state level involvement in tobacco production appears to limit the effectiveness of anti-industry ads to prevent tobacco use among adolescents in the USA. Design: Time trend analyses were done using repeated cross sectional data from six waves of the Legacy Media Tracking Survey, which were collected between 1999 and 2003. Setting and participants: 28 307 adolescents, ages 12–17 years, were classified as living in: tobacco producing states (TPS) (n = 1929); non-tobacco producing states (non-TPS) with low tobacco control funding comparable to TPS (n = 5323); non-TPS with relatively high funding (n = 15 076); and non-TPS with established anti-industry ad campaigns (n = 5979). Main outcome measures: Reactions to anti-industry ads; strength of anti-industry attitudes/beliefs; changes in anti-industry attitudes/beliefs over time. Results: Ad reactions did not differ by state type. Multivariate adjusted time trend analyses indicated significant, comparable increases in anti-industry attitudes/beliefs since the onset of the truth® campaign, in both TPS and non-TPS. Mediation analyses indicated that these increases were due, in part, to campaign exposure. Conclusions: Adolescents who live in tobacco producing regions appear to be as responsive to anti-industry ads as their counterparts in non-tobacco producing regions. This study provides further evidence for the effectiveness of such ads.     

What should be the elements of any settlement with the tobacco industry?

Litigation and regulatory assaults on the tobacco companies may create a willingness among tobacco manufacturers to bargain resources and acceptance of public policy changes for limitations of liability, as has been seen by the recent settlement with the Liggett Group. Two elements absolutely critical to any plan are the elimination of tobacco advertising and promotion and the removal of addiction as a reason for tobacco use. Minimal components of any settlement should include: (a) acceptance by the tobacco manufacturers of the causal relationship between tobacco use and disease, and the addictive nature of nicotine; (b) a total ban on tobacco advertising and promotion; (c) FDA jurisdiction over tobacco products and their nicotine content, with the intent of removing nicotine as soon as acceptable nicotine substitution products are available; (d) reimbursement to the states for Medicaid and other state expenditures attributable to smoking, to the maximum extent feasible; (e) funding for local, state, and federal programmes and research in tobacco control; (f) acceptance of legislation and regulations protecting the right of non-smokers to breathe air free of tobacco smoke; (g) funding for a large, national, media-led, anti- tobacco campaign; and (h) cessation assistance for addicted smokers. If negotiations toward a settlement proceed, it is essential that the public health community participate in defining the elements of any agreement to ensure that whatever agreement develops is focused on reducing tobacco-related disease rather than continuing the profitability of American tobacco companies. That participation requires articulation of the core elements essential to an acceptable agreement. If resolution of the public health issues surrounding continued sale of tobacco products can be reached in the United States, it may provide a model for similar resolution in other countries.


     

Holstein-Friesian calves selected for divergence in residual feed intake during growth exhibited significant but reduced residual feed intake divergence in their first lactation

Residual feed intake (RFI), as a measure of feed conversion during growth, was estimated for around 2,000 growing Holstein-Friesian heifer calves aged 6 to 9 mo in New Zealand and Australia, and individuals from the most and least efficient deciles (low and high RFI phenotypes) were retained. These animals (78 New Zealand cows, 105 Australian cows) were reevaluated during their first lactation to determine if divergence for RFI observed during growth was maintained during lactation. Mean daily body weight (BW) gain during assessment as calves had been 0.86 and 1.15 kg for the respective countries, and the divergence in RFI between most and least efficient deciles for growth was 21% (1.39 and 1.42 kg of dry matter, for New Zealand and Australia, respectively). At the commencement of evaluation during lactation, the cows were aged 26 to 29 mo. All were fed alfalfa and grass cubes; it was the sole diet in New Zealand, whereas 6 kg of crushed wheat/d was also fed in Australia. Measurements of RFI during lactation occurred for 34 to 37 d with measurements of milk production (daily), milk composition (2 to 3 times per week), BW and BW change (1 to 3 times per week), as well as body condition score (BCS). Daily milk production averaged 13.8 kg for New Zealand cows and 20.0 kg in Australia. No statistically significant differences were observed between calf RFI decile groups for dry matter intake, milk production, BW change, or BCS; however a significant difference was noted between groups for lactating RFI. Residual feed intake was about 3% lower for lactating cows identified as most efficient as growing calves, and no negative effects on production were observed. These results support the hypothesis that calves divergent for RFI during growth are also divergent for RFI when lactating. The causes for this reduced divergence need to be investigated to ensure that genetic selection programs based on low RFI (better efficiency) are robust.