Atom counting in ultracold gases using photoionization and ion detection

We analyze photoionization and ion detection as a means of accurately counting ultracold atoms. We show that it is possible to count clouds containing many thousands of atoms with accuracies better than N-1/2 with current technology. This allows the direct probing of sub-Poissonian number statistics of atomic samples. The scheme can also be used for efficient single-atom detection with high spatiotemporal resolution. All aspects of a realistic detection scheme are considered, and we discuss experimental situations in which such a scheme could be implemented.

Overcoming the problem of loss-in-capacity of calcium oxide in CO2 capture

Calcium oxide has been identified to be one of the best candidates for CO2 capture in zero-emission power-generation systems. However, it suffers a well-known problem of loss-in-capacity (i.e., its capacity of CO2 capture decreases after it undergoes cycles of carbonation/decarbonation). This problem is a potential obstacle to the adoption of the new technologies. This paper proposes a method of fabricating a CaO-based adsorbent without the problem of loss-in-capacity. An adsorbent was fabricated using the method and tested on a thermogravimetric analyzer. It was shown that the sorbent attained a utilization efficiency of more than 90% after 9 cycles of carbonation/decarbonation.

Effect of seasonal variation and storage temperature on leaf chlorophyll fluorescence and vase life of cut roses

Low temperature injury (LTI) of roses (Rosa hybrida L.) is difficult to assess by visual observation. Relative chlorophyll fluorescence (CF; F-v/F-m) is a non-invasive technique that provides an index of stress effects on photosystem 11 (PS 11) activity. This instrumental technique allows determination of the photosynthetic efficiency of plant tissues containing chloroplasts, such as rose leaves. In the present study, pre- and Post-Storage measurements of F-v/F-m were carried out to assess LTI in 'First Red' and 'Akito' roses harvested year round. Relationships between the pre-harvest environment conditions of temperature, relative humidity and photon flux density (PFD), F-v/F-m, and, vase life duration after storage are reported. After harvest, roses were stored at 1, 5 and 10 degrees C for 10 days. Non-stored roses were the control treatment. F-v/F-m ratios were reduced following storage, suggesting LTI of roses. However, reductions in F-v/F-m were not closely correlated with reduced vase life duration and were seasonally dependent. Only during winter experiments was F-v/F-m of roses stored at 1 degrees C significantly (P <= 0.001) lower compared to F-v/F-m of non-stored control roses and roses stored at 5 and 10 degrees C. Thus, the fall of F-v/F-m was due to an interaction of growing season and storage at 1 degrees C. Vase lives of roses grown during winter were significantly (P <= 0.001) shorter compared to roses grown during summer. Length of vase life was intermediate for roses grown during autumn and spring. Because of the lack of correlation between F-v/F-m and post-storage vase life it is concluded that the CF parameter F-v/F-m is nota practical index for assessing LTI in cold-stored roses. Higher PFD and temperature in summer were positively and significantly correlated with maintenance of post-storage FvIF ratios and longer vase life. It is suggested that shorter vase lives and lower post-storage F-v/F-m values after storage at 1 degrees C are consequences of reduced photosynthesis and smaller carbohydrate pools in winter-harvested roses. (c) 2004 Elsevier B.V All rights reserved.

Optimum coal properties and engineering processes for CO2 geosequestration in Coal

CO2 Geosequestration is seen by many worldwide scientists and engineers as a leading prospective solution to the global warming problem arising from excessive CO2 and other greenhouse gas emissions. CO2 geosequestration in coal seams has two important strategic benefits: the process has an extremely low risk of leakage, due to the adsorbed state of the CO2 and the known reservoir context of essentially-zero leakage into which it is be injected; the second benefit arises from the valuable by-product, clean burning coalbed methane gas. This paper presents the authors’ experience, knowledge and perspective on what coal properties and engineering processes would favour implementing a demonstration or commercial CO2 storage-in-coal project, in Queensland, Australia. As such, it may be considered a template for screening studies to select the optimum coal seam reservoir, and for preliminary studies in designing the injection system and predicting production response to the technology. The paper concludes by examining the current knowledge gaps of CO2 geosequestration in coal, identifying further basic and applied research topics.

The effect of tidal volume and peep on CO2 and oxygenation during resuscitation of very premature lambs

Background: Over-ventilation causing low arterial carbon dioxide levels (PaCO2) has been associated with the development of neonatal chronic lung disease and adverse outcomes. This may occur very soon after birth. Aim: To investigate the effect on PaCO2 and oxygenation of very premature lambs resuscitated with different tidal volumes and PEEP. Methods: Anaesthetised lambs delivered at 126 days gestation were randomised to 15 min resuscitation with 3 regimes: (1) Laerdal resuscitation bag (B) with 100% oxygen and no PEEP, (2) fixed tidal volume (VT) of 5 mL/kg, or (3) VT of 10 mL/kg, both delivered with a Babylog 8000 ventilator in volume guarantee mode with 8 cm H2O PEEP and variable FiO2. Frequent blood gases were measured and VT, mean airway pressure (Paw), minute volume (MV), ventilation rate (VR), respiratory system compliance (Crs) and alveolar/arterial oxygen difference (AaDO2) were recorded. Results: Twenty lambs were studied. B (1) was associated with more variable VT and peak inspiratory pressures (PIP) compared to fixed tidal volumes (2 and 3). The lambs ventilated with 10 mL/kg were over-ventilated, those ventilated with 5 mL/kg were slightly under-ventilated. Those ventilated with the Laerdal bag had a mean VT of 7.5 mL/kg and were normocarbic. The different tidal volumes had little effect on oxygenation. PEEP improved oxygenation. The table shows the values at 15 minutes expressed as mean and SEM. TABLE. No caption av... TABLE. No caption av... Image Tools Conclusion: Very premature lambs can be effectively resuscitated from birth using volume guarantee ventilation. Within minutes of birth different tidal volumes had a large effect on PaCO2 and no effect on oxygenation. Studies are needed to determine the appropriate tidal volume for resuscitating very premature infants to maintain acceptable levels of PaCO2. © International Pediatrics Research Foundation, Inc. 2004. All Rights Reserved.