Copper… on the one hand copper is an important trace element for life (for example as part of the red blood cells), on the other hand it is toxic. Water-soluble copper in inshore waters and soil is a danger for many microorganisms and plants. Therefore, it is important to understand the dispersion of water-soluble copper. When you add water-soluble copper (Cu) into soil, it instantly partitions between solid and solution phases. However, this state is not stable: with increasing “age”, its lability (bioavailability, toxicity, isotopic exchange-ability and extractability) decreases because of diffusion and reactions with the surrounding material. Theoretical models help to predict this time dependent change in lability, which depends on a lot of soil parameters like temperature, soil organic matter content and soil pH. Zeng, et al. (2017) published an improved model for copper lability which describes short and long term effect of water-soluble copper added to soil in one single model. In their model, copper lability depends on three processes:
The model showed good predicting ability when compared to experimental data of different soil samples with different chemical properties (like pH value, clay and organic carbon content and copper concentration), although other copper ageing processes like moisture, plant absorption, and microbial activities are not considered. "A new model integrating short- and long-term aging of copper added to soils"
Zeng S, Li J, Wei D, Ma Y (2017) PLOS ONE 12(8): e0182944.
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Lithium-ion batteries are everywhere: in your smartphone, in your camera, … These types of rechargeable batteries are great for any portable electronics as it has a small memory effect and low self-discharge. However, that doesn’t mean that it can’t be improved. In 2007, Fu et al. tested three-dimensionally ordered mesoporous titania microparticles as “new” anode material. Why titania? I don’t know. Fact is, “conventional Li-storage materials suffer serious capacity loss when they are charged/discharged at a high rate. Polarization caused by slow diffusion of lithium ions and electrons in active materials is one challenging problem.“ As far as I understand it (and please my dear reader correct me if I am wrong) that means, that the lithium ions need a certain time to travel between between the electrodes. Therefore, if you are charging and discharging faster than the lithium ions need to travel from the one electrode to the other, this results in a capacity loss. Normally the anode in a lithium ion battery is made of graphitic layers. Between the stacked layers the lithium ions are normally stored in the charging process. While discharging, the lithium ions travel to the cathode. So summing up, the traveling time between the anode and the cathode (and the other way around) is the reason for polarization. However, “previous studies showed that electrode materials with three-dimensionally (3D) ordered mesoporous structure could decrease the polarization and enhance the performance at high rates”. That means that if the electrode material has a 3d structure with “pores” instead of the graphitic layers, the lithium ions can travel faster and so the polarization is decreased. Therefore, Fu et al. created a 3D ordered mesoporous structure out of titania and used it as anode. Indeed, the 3d structure was “beneficial to the diffusion of lithium ions” which reduced the capacity loss. So 3d is better than 2d… at least regarding the structure of the anode material in lithium ion batteries… (for movies I still prefer 2d… but this is maybe a question of taste). "Preparation and characterization of three-dimensionally ordered mesoporous titania microparticles as anode material for lithium ion battery."
Fu et al. Electrochemistry Communications 9.8 (2007): 2140-2144. Matrix isolation is an experimental technique in which guest particles (atoms, molecules, ions, etc.) are embedded in a matrix of unreactive host substrates. Embedded in the matrix, the guest particles are isolated from each other. Diffusion processes and chemical reactions between the guest particles are prevented (reactions between guest and host particles are possible). “The matrix isolation technique was first introduced in 1954 by Pimentel and co-workers, who used the technique for systematic studies of free radicals and other unstable or transient species.“ (http://www.ruhr-uni-bochum.de/oc2/matrix.html). Initially matrix isolation was used to describe the embedding of guest particles in any unreactive material, but today mainly gases in low temperature solids are used as host medium (https://en.wikipedia.org/wiki/Matrix_isolation). That is interesting, as the paper written by Anthony J. Rest in 1990 showed that “many low temperature media, which have been regarded as ‘infra dig’, can produce results which are analogous to those obtained using gas matrices”. "Infra dig matrix media."
Anthony J. Rest Journal of Molecular Structure222.1-2 (1990): 87-93. Air quality is a main problem of the civilization. Therefore, models predicting air pollution become more and more important. And this is quite easy. Let Aurora work together with albatross, and you will get good predictions. Of course I am referring to the paper of Carolien Beckx et al. (2009) and ALBATROSS and AURORA are models: A Learning-Based Transportation Oriented Simulation System and Air quality modelling in Urban Regions using an Optimal Resolution Approach. ALBATROSS is an activity-based model which predicts people's travel behaviour and the resulting vehicle emissions. It is based on approximately 10,000 person-day activity-diaries of Dutch. The predictions of vehicle emissions can be used as input for the air quality model AURORA. As “prognostic 3-dimensional Eulerian model of the atmosphere”, AURORA predicts how air pollutants (gas and particla) are transported in the air, including physical changes and chemical reactions which generate new pollutants. Using meterological parameters like wind, temperature, humidity, precipitation, radiation,…, AURORA calculates 3-dimensional concentration fields for different pollutants. Beckx et al. (2009) tested this model combination by comparing the model predictions for three different pollutants with real air quality data measured in different stations all over the Netherlands. Inside the country, the agreement between modelled and observed concentrations varied between the different pollutants but was sufficient for all of them. The only problems are the borders of the Netherlands, maybe because of wrong calculation of the contribution of foreign traffic. Maybe they underestimated how many people like to visit the Netherlands? The contribution of activity-based transport models to air quality modelling: a validation of the ALBATROSS–AURORA model chain
Carolien Beckx, et al. Science of the Total Environment 407.12 (2009): 3814-3822 Maori were the first settler of New Zealand. Richard C. Cambie and Lynnette R. Ferguson published a paper in 2003 in which they discuss if the rise of diabetes, cancer and vascular related diseases in Maori people lately may be related to change in the diet. Were there any protective chemical constituents in the food plants of the traditional Maori diet which are now missing? In the survey they listed the chemical components of food plants which were part of the traditional Maori diet. Indeed they found a lot of different chemical constituents with anti-inflammatory, anti-cancer, anti-coagulation, anti-ulcer, anti-hepatoxin and anti-viral activity and positive effects on capillary walls and eye sight. This medical properties of the traditional Maori diet may suppressed diseases like diabetes, cancer and vascular related diseases but more details about the changed diet would be needed for a more detailed discussion. However, the survey shows the medical potential of some native plants in New Zealand. Potential functional foods in the traditional Maori diet.
Richard C. Cambie and Lynnette R. Ferguson Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 523, 109-117 (2003) PMID: 12628508 |
IdeaI love to increase my general science knowledge by reading papers from different fields of science. Here I share some of them. Archiv
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