Twisting of Porphyrin by Assembly in a Metal-Organic Framework yielding Chiral Photoconducting Films for Circularly-Polarized-Light Detection

While materials based on organic molecules usually have either superior optoelectronic or superior chiral properties, the combination of both is scarce. Here, a crystalline chiroptical film based on porphyrin with homochiral side groups is presented. While the dissolved molecule has a planar, thus, achiral porphyrin core, upon assembly in a metal–organic framework (MOF) film, the porphyrin core is twisted and chiral. The close packing and the crystalline order of the porphyrin cores in the MOF film also results in excellent optoelectronic properties. By exciting the Soret band of porphyrin, efficient photoconduction with a high On-Off-ratio is realized. More important, handedness-dependent circularly-polarized-light photoconduction with a dissymmetry factor g of 4.3×10⁻⁴ is obtained. We foresee the combination of such assembly-induced chirality with the rich porphyrin chemistry will enable a plethora of organic materials with exceptional chiral and optoelectronic properties.     

On multiple series of Eisenstein type

The aim of this paper is to study certain multiple series which can be regarded as multiple analogues of Eisenstein series. As part of a prior research, the second-named author considered double analogues of Eisenstein series and expressed them as polynomials in terms of ordinary Eisenstein series. This fact was derived from the analytic observation of infinite series involving hyperbolic functions which were based on the study of Cauchy, and also Ramanujan. In this paper, we prove an explicit relation formula among these series. This gives an alternative proof of this fact by using the technique of partial fraction decompositions of multiple series which was introduced by Gangl, Kaneko and Zagier. By the same method, we further show a certain multiple analogue of this fact and give some examples of explicit formulas. Finally we give several remarks about the relation between the results of the present and the previous works for infinite series involving hyperbolic functions.     

Kannappan’s functional equation on semigroups with involution

We express the complex-valued solutions of Kannappan’s functional equation on semigroups with involution in terms of solutions of d’Alembert’s functional equation.     

To Tattoo or not to Tattoo

Tattoos are part of our cultural heritage, often admired, often condemned. During the last few decades we saw a remarkable revival and tattoos became fashionable. Today about 100 million Europeans have at least one tattoo. Most of them are not aware of the corresponding health risks and the almost complete lack of any legal regulations, neither of the education and qualification of tattoo artists, nor the hygienical conditions of their equipment and the quality of the injected dyes. In order to shed light into the whole tattoo process, the procedure itself and the fate of the dyes in the customers skin are analyzed from a chemical perspective.     

Characterisation of dolomites before and after reactivity measurement with HCl solution

The aim of this study was to compare different types of dolomites through batch reactivity experiments between HCl and dolomite powders, and ex‐situ characterisation of the particles before and after dissolution. Sedimentary dolomites were observed to have higher initial reactivities than metamorphic ones with sufficiently low calcite concentrations (<6% according to our regression model). In addition, the initial reactivities of the metamorphic dolomites were dependent on calcite concentration and could exceed those of the sedimentary dolomites. A regression model is presented for the dependence of initial reactivity on mineral composition and type of origin (sedimentary/metamorphic). The samples with the highest initial reactivities had also the largest BET (Brunauer, Emmet, Teller) surface areas obtained with nitrogen physisorption. Yet our data indicates that mineral composition of the dolomite has a greater influence on the initial reactivity than the BET surface area. Furthermore, it was found that the surface of sedimentary dolomites, unlike the surface of metamorphic dolomites, becomes porous during dissolution. Copyright © 2014 John Wiley & Sons, Ltd.     

Thermal dynamics of a block-filled underground hot water store

One of the best methods for seasonal storage of solar heat is the storage of hot water in large unlined rock caverns. A safe method to build self stabilizing very large caverns is to excavate them partially, i.e. to leave a considerable amount of the blasted rock in the cavern.The remaining rock in such a hot water store represents an undesired thermal inertia and it is of great practical interest to estimate how the remaining blocks influence the performance of the store.If the cavity is assumed to be spherical, the remaining blocks spherical as well, the heat diffusitivity of the solid matter constant and the water well stirred, the temperature of the water can rather easily be calculated. In the present paper it is shown that the coupled system of partial differential equations and one ordinary differential equation can be reduced to a Volterra integral equation. The calculations show how the porosity and the size of the remaining blocks influence the water temperature if an arbitrary power is added to or extracted from the cavern.     

Oscillations in two wells drilled in a confined aquifer

If two wells are connected to a confined aquifer and the water level in one of the wells is perturbed, damped oscillations in the wells might occur. A criterion in terms of nondimensional parameters is derived which tells when the damping is critical.     

Pressurized-fluid extraction (PFE) of chlorinated paraffins from the biodegradable fraction of source-separated household waste

A method is presented in which pressurized-fluid extraction (PFE) is used for the extraction of chlorinated paraffins (CP) from the biodegradable fraction of source-separated household waste. The conditions that were optimized for high recovery in the extraction procedure were extraction time, temperature, and the use of different solvents and different sample particle sizes. Recoveries of CP from fortified household waste material were over 90%, with only few interferences when cyclohexane was used as solvent. Extraction yields from contaminated samples containing CP were further compared with recoveries obtained by use of Soxtec extraction. The results showed that PFE is a rapid, low-solvent-consuming technique, giving high yields. Received: 13 November 2000 / Revised: 2 March 2001 / Accepted: 7 March 2001     

Measurement of inorganic acids with rotating ball inlet mass spectrometry

Using a new acid resistant inlet we have evaluated the use of rotating ball inlet mass spectrometry (ROBIN-MS) as a tool for the measurement of inorganic acids in aqueous solution. EI-spectra of sulfuric, sulfurous, nitric, perchloric, bromic, iodic and boric acids were recorded and interpreted with respect to preionization decomposition and electron impact fragmentation. With the exception of sulfuric acid the detection limits for these acids were in the order of 1 mM and the response times are in the order of 1 s. Sulfuric acid had a significantly higher detection limit and response time than the other acids. No mass spectrum of phosphoric acid could be detected. High concentrations of phosphoric acid reduced the signals of other acids. HCl formed by decomposition of perchloric acid caused a strong and slowly recovering decrease of the sensitivity of the mass spectrometer. Sodium sulfate or sodium nitrate in neutral solution did not yield any mass spectrum. The intensity of the sulfuric acid peak of acid solutions of sodium sulfate was measured at different molar ratios of sodium and sulfate. The results indicate that the evaporation of such samples leaves a remnant containing three molecules of sulfuric acid per sodium ion. Similar measurements on acid solutions of sodium nitrate indicate that the remnant contains one molecule of nitric acid per sodium ion.