Transfer process limited models for CO2 perception in CO2 hydrate desserts

A CO₂ hydrate dessert is a carbonated frozen dessert in which CO₂ hydrates replace some or all of the ice. When a CO₂ hydrate dessert is eaten, CO₂ perception is very strong due to formation and bursting of bubbles in the mouth as well as dissolution of CO₂ leading to nociceptor stimulation. A preliminary sensory panel indicated that a CO₂ hydrate dessert could be perceived as more carbonated than a freshly opened soda. However, it was also found that a CO₂ hydrate dessert must have a significantly higher CO₂ concentration than is typical in carbonated beverages (including champagne), just to have moderate perception of carbonation. In this work, heat transfer limited and mass transfer limited models for CO₂ hydrate dissociation are compared and the implications for CO₂ perception are discussed. It is suggested that the mass transfer limited model is most applicable to the case of eating CO₂ hydrate desserts. According to this model, a thin ice shell limits the rate of CO₂ hydrate dissociation. After dissociation, CO₂ gas is dissolved in the available aqueous phase. In a CO₂ hydrate there is much more CO₂ present than could be dissolved in the water that is present, so a large fraction of the CO₂ in the dessert may be lost with the breath of the consumer.     

Review: soil biological properties as indicators of soil quality in Australian viticulture

Any reduction in soil quality as a consequence of production practices, through processes, such as erosion, salinisation, sodicity, acidity and structural decline, threatens the long‐term sustainability of winegrape production. Monitoring of soil quality is thus needed to identify when degradation is occurring in order to allow management intervention. This review examines the suite of biological indicators available for this purpose and the potential for their adoption as part of a minimum dataset by industry. Physical and chemical indicators are discussed in a companion paper. Many groups of organisms and various biological processes have been used as indicators of soil quality in research programs. There is a lack of consensus, however, on which are the key indicators for extensive monitoring programs, and little information is available on threshold values to aid data interpretation. At present, only soil organic carbon (together with labile carbon), potentially mineralisable nitrogen and microbial biomass can be recommended for measuring the biological aspects of soil quality in Australian viticulture. Although newer molecular methods have been developed to elucidate the community structure and genetic profiles of groups in the soil biota, and thus supplement measurements of microbial biomass, these methods are not readily available through commercial laboratories. Moreover, with the exception of tests for some pathogenic organisms, these measurements have not yet been linked to soil functions influencing grapevine growth and nutrition and so are not suitable for routine monitoring of vineyard soil quality.     

Opinion on the use of plasma processes for treatment of foods*

The working group “Food technology and safety” of the DFG Senate Commission on Food Safety (SKLM) advises on new technologies concerning food processing. Treatment with plasma is a newly developed process, which is currently used only on a pilot scale in Europe. The novel plasma treatment technology is experimentally applied to consumer goods. There are also potential applications in the food sector, e.g. to inactivate microorganisms on food surfaces. There is still insufficient information on concomitant physical and chemical processes and changes induced in the food. On May 25th 2012, the SKLM issued a first statement on plasma treatment of foods in German. The English version was agreed on December 14th 2012.     

Long‐range wireless sensor networks with transmit‐only nodes and software‐defined receivers

Wireless sensor networks for environmental monitoring and agricultural applications often face Long‐range requirements at low bit rates together with a large numbers of nodes. This paper presents the design and test of a novel wireless sensor network that combines a large radio range with very low power consumption and cost. Our asymmetric sensor network uses ultra‐low‐cost 40‐MHz transmitters and a sensitive software‐defined radio receiver with multi‐channel capability. Experimental radio range measurements in two different outdoor environments demonstrate a single‐hop range of up to 1.8 km. A theoretical model for radio propagation at 40 MHz in outdoor environments is proposed and validated with the experimental measurements. The reliability and fidelity of network communication over longer periods is evaluated with a deployment for distributed temperature measurements. Our results demonstrate the feasibility of the transmit‐only low‐frequency system design approach for future environmental sensor networks. Although there have been several papers proposing the theoretical benefits of this approach, to the best of our knowledge, this is the first paper to provide experimental validation of such claims. Copyright © 2011 John Wiley & Sons, Ltd.     

An improved accelerated weathering protocol to anticipate Florida exposure behavior of coatings

A new accelerated weathering protocol has been developed which closely replicates the performance of automotive and aerospace coating systems exposed in South Florida. IR spectroscopy was used to verify that the chemical composition changes that occurred during accelerated weathering in devices with a glass filter that produced a high fidelity reproduction of sunlight’s UV spectrum matched those that occurred during natural weathering. Gravimetric water absorption measurements were used to tune the volume of water absorption during accelerated weathering to match that which occurred during natural weathering in South Florida. The frequency of water exposure was then scaled to the appropriate UV dose. A variety of coating systems were used to verify the correlation between the physical failures observed in the accelerated weathering protocol and natural weathering in South Florida. The new accelerated weathering protocol correctly reproduced gloss loss, delamination, cracking, blistering, and good performance in a variety of diverse coating systems. For automotive basecoat/clearcoat paint systems, the new weathering protocol shows significant acceleration over both Florida and previous accelerated weathering tests. For monocoat aerospace systems, the new weathering protocol showed less acceleration than for automotive coatings, but was still an improvement over previous accelerated tests and was faster than Florida exposure.     

Dendrimers or Nanoparticles as Supports for the Design of Efficient and Recoverable Organocatalysts?

The Jørgensen–Hayashi catalyst [(S)‐α,α‐diphenylprolinol trimethylsilyl ether] was grafted onto the surface of two different supports: phosphorus dendrimers (generations 1 to 3) and magnetic, polymer‐coated cobalt/carbon (Co/C) nanobeads. These new supported catalysts displayed high activities and selectivities in the Michael additions of a wide range of aldehydes to different nitroolefins. Moreover, the dendrimer of the third generation displayed excellent recycling abilities since it could be recovered and reused in 7 consecutive runs without loss of activity.     

A Shelter to Protect a Passive Sampler for Coarse Particulate Matter,PM10 − 2.5

This work designed and tested a shelter to protect a passive sampler for measuring coarse particulate matter, PM _{10 ? 2.5} . The shelter protects the sampler from precipitation and reduces the effects of wind on the deposition of particles to its collection surface. Six shelters were tested in a wind tunnel at three wind speeds: 2, 8, and 24 km hr ^?1 . Shelter performance was expressed as the ratio of PM _{10 ? 2.5} measured with the passive samplers to that measured with a filter-based dichotomous sampler. For most shelters, the PM _{10 ? 2.5} ratio averaged across wind speeds was well above one (2.4 to 8.5) and was generally dependent on wind speed. However, the PM _{10 ? 2.5} ratio for one shelter, the Flat Plates shelter, was 1.04 with substantially less effect on particle deposition from wind speed. Eight week-long field tests were conducted to compare PM _{10 ? 2.5} measured with a passive sampler installed in a Flat Plates shelter to that measured with a collocated filter-based dichotomous sampler. In these tests, the mean PM _{10 ? 2.5} ratio was 1.29. The linear relationship between PM _{10 ? 2.5} measured passively to that measured with the filter-based sampler had a Pearson correlation coefficient of 0.97 and was not significantly affected by the addition of weekly mean wind speed (p = 0.35). Although temperature was significant in this regression model (p = 0.02), it only improved the relationship marginally. The passive sampler in a Flat Plates shelter offers an inexpensive means to assess ambient PM _{10 ? 2.5} without on-site measurement of wind speed.     

Effect Of Roller Profile On Cylindrical Roller Bearing Life Prediction—Part II Comparison of Roller Profiles

Four roller profiles used in cylindrical roller bearing design and manufacture were analyzed using both a closed form solution and finite element analysis (FEA) for stress and life. The analyzed roller profiles were flat, end tapered, aerospace, and fully crowned and loaded against a flat raceway. Four rolling-element bearing life models were chosen for this analysis: those of Weibull; Lundberg and Palmgren; Ioannides and Harris; and Zaretsky. The flat roller profile without edge loading has the longest predicted life. However, edge loading can reduce life by as much as 98 percent. The end-tapered profile produced the highest lives, but not significantly higher than those produced by the aerospace profile. The fully crowned profile produced the lowest lives. Except for the flat roller profile, the predicted lives with the FEA method exceed those with the closed form solution. The fatigue limit proposed by Ioannides and Harris equates to one-half the value of a compressive residual stress that may exist in a rolling bearing steel.     

Performance of scientific cameras with different sensor types in measuring dynamic processes in fluorescence microscopy

The plethora of available scientific cameras of different types challenges the biologically oriented experimenter when picking the appropriate camera for his experiment. In this study, we chose to investigate camera performances in a typical nonsingle molecule situation in life sciences, that is, quantitative measurements of fluorescence intensity changes from video data with typically skewed intensity distributions. Here, intensity profile dynamics of pH‐sensors upon triggered changes of pH‐environments in living cells served as a model system. The following camera types were tested: sCMOS, CCD (scientific and nonscientific) and EM‐CCD (back‐ and front‐illuminated). We found that although the EM‐CCD cameras achieved the best absolute spatial SNR (signal‐to‐noise ratio) values, the sCMOS was at least of equal performance when the spatial SNR was related to the effective dynamic range, and it was superior in terms of temporal SNR. In the measurements of triggered intensity changes, the sCMOS camera had the advantage that it used the smallest fraction of its dynamic range when depicting intensity changes, and thus featured the best SNR at full usage of its dynamic range. Microsc. Res. Tech. 76:835–843, 2013. © 2013 Wiley Periodicals, Inc.