Thickening of molten white chocolates during storage

When white chocolates are kept molten in storage tanks, problems can arise due to uncontrolled thickening and solidifying of the chocolate mass. The thickening of molten white chocolate was simulated on a laboratory scale using a rotational rheometer under static conditions, interrupted by short shear periods to measure the increasing viscosity. Several chocolates having different dairy components and fat contents were investigated for their tendency to thicken. In addition, sorption isotherms for white chocolates were obtained using dynamic vapour sorption at different temperatures. The sorption isotherms showed the presence of amorphous lactose in all the chocolates that were manufactured from milk powders. Moisture that is released during the crystallization of amorphous lactose causes stickiness and agglomeration of the neighbouring particles and starts the thickening process. This process is highly temperature-dependent. On elevating the temperature the lactose crystallization occurs at lower relative humidities. In order to reduce the tendency of white chocolate to thicken, a high free-fat level should be maintained, based on a high total fat content and on the use of high free-fat milk powders, preferably roller-dried whole milk powders or the combination of skimmed milk powder and anhydrous milk fat.     

Electrochemical and spectroscopic characterization of lithium titanate spinel Li4Ti5O12

Herein we describe electrochemical and spectroscopic properties of lithium titanate spinel as well as an easy method based on colorimetry to determine the lithium content of electrodes containing lithium titanate spinel as active material. Raman microspectrometry measurements have been performed to follow lithium insertion into and extraction from the active material, respectively. The Raman signals display a pronounced fading of intensity already at low levels of lithium intercalation and disappear at a SOC higher than ∼10%. However, the colorimetric method can be used up to a SOC of 50%.     

A Critical Assessment of Experimental Methods for Determining the Dynamic Mechanical Characteristics of Shape Memory Polymers

Experimental study of temperature‐ and frequency‐dependent properties of the commercially available shape memory polymer Tecoflex? EG 72D (TFX) (Lubrizol, USA) using dynamic mechanical analysis (DMA) technique is presented. Temperature scan DMA tests have been carried out in three distinct deformation modes, uniaxial tension, three‐point bending, and simple torsion, using two different testing rigs at different test parameters (frequency, strain amplitude, and heating rate) in temperatures ranging from below to above the glass transition temperature. The influence of different test parameters and some discrepancies in the temperature‐dependent storage and loss moduli (and hence the loss factor) measured by DMA in different deformation modes are discussed.     

The effect of Al–O substitution for Si–N on the luminescence properties of YAG:Ce phosphor

The present paper describes the effect of various Si–N substitution degree on the crystal structure and optical properties of yellow YAG:Ce phosphor commonly used with combination of InGaN in white LEDs. It has been found that the course of silicon/nitrogen YAG:Ce garnet doping as well as formation of the liquid phase and its chemical composition controlled formation of the side phase besides YAG:Ce. Substitution of Al–O for Si–N chemical bonds according to the general formula Y_2.94Ce_0.06Al_(5?x)Si_xO_(12?x)N_x was confirmed by changes of the unit cell parameter and formation of the Si–N bonds as detected by FT-IR studies. Formation of the nitrogen ligand in cerium arrangement resulted in a red shift in emission spectrum of trivalent cerium if nominal x value was in the range of 0.2–0.3. Above x = 0.3 only decrease of emission intensity was observed because of the secondary phase precipitation but further solution of Si–N in YAG:Ce crystal lattice cannot be excluded.     

LIQHYSMES storage unit – Hybrid energy storage concept combining liquefied hydrogen with Superconducting Magnetic Energy Storage

A new energy storage concept for variable renewable energy, LIQHYSMES, has been proposed which combines the use of LIQuid HYdrogen (LH2) with Superconducting Magnetic Energy Storage (SMES). LH2 with its high volumetric energy density and, compared with compressed hydrogen, increased operational safety is a prime energy carrier for large scale stationary energy storage. But balancing load or supply fluctuations from seconds to several hours with hydrogen alone is difficult due to the response times of the flow control, and an additional short-term electrical energy storage will be needed. For this purpose a compact LIQHYSMES Storage Unit is proposed which integrates the H2 liquefaction part, the LH2 tank and the SMES based on Magnesium Diboride and cooled by the LH2 bath. This allows jointly utilizing the cryogenic infrastructure and reducing the otherwise significant H2 liquefaction losses by introducing a novel process with “cold recovery”. Preliminary target numbers for this process, key parameters for a complete LIQHYSMES model plant, simulations on the anticipated buffering behaviour, a loss analysis and a crude cost estimate are given.     

Sustainability and property valuation: a risk-based approach

The proportion of sustainable property in the total building stock remains small. One reason is that the financial added value resulting from sustainability is not sufficiently taken into account in property valuation due to the tendency of valuations to lag behind market trends. Quantitative information is provided to integrate those aspects of sustainability relating to value into valuations and thereby contribute to the reduction of valuation lag. The Centre for Corporate Responsibility and Sustainability (CCRS) Economic Sustainability Indicator (ESI) measures the risk of property to lose value and the opportunity to gain value due to future developments (e.g. climate change or rising energy prices). Five groups of value-related sustainability features were identified: flexibility and polyvalence; energy and water dependency; accessibility and mobility; security; and health and comfort. By minimizing the risk of loss in value through future developments, those sustainability features contribute to the property value. Their effects on property value were quantified by risk modelling. As an indicator for future-oriented property risk, the ESI is integrated into the discount rate of discounted cash flow valuations. The approach was tested for plausibility and practicability on more than 200 properties.

La proportion de biens immobiliers durables dans le parc immobilier total demeure faible. L'explication tient pour une part au fait que la valeur ajoutée financière résultant de la durabilité n'est pas suffisamment prise en compte dans l'évaluation des biens immobiliers en raison du fait que les évaluations tendent à avoir du retard sur les tendances du marché. Des informations quantitatives sont fournies afin d'intégrer les aspects de la durabilité liés à la valeur dans les évaluations et de contribuer ainsi à la réduction du retard dans les évaluations. L'Indicateur de Durabilité Economique (ESI) du Centre pour la Responsabilité et la Durabilité en Entreprise (CCRS) mesure le risque de perte de valeur des biens immobiliers et la possibilité d'en accroître la valeur du fait des évolutions futures (par ex. changement climatique et hausse des prix énergétiques). Cinq groupes de fonctions de durabilité liées à la valeur ont été identifiés: flexibilité et polyvalence, dépendance vis-à-vis de l'énergie et de l'eau; accessibilité et mobilité; sécurité; santé et confort. En minimisant le risque d'une perte de valeur causée par les évolutions futures, ces fonctions de durabilité contribuent à la valeur des biens immobiliers. Leurs effets sur la valeur des biens immobiliers ont été quantifiés par une modélisation des risques. En tant qu'indicateur du risque prospectif pour les biens immobiliers, l'ESI est intégré au taux d'actualisation des flux de trésorerie actualisés. Cette approche a été testée quant à sa plausibilité et sa praticabilité sur plus de 200 biens immobiliers.

Mots clés: flux de trésorerie actualisés, indicateur de durabilité économique, évaluation des biens immobiliers, modèle de risque, fonctions de durabilité, durabilité, bâtiments durables     

A precious-metal free micro fuel cell accumulator

In recent years, integrated fuel cell (FC) type primary and secondary batteries attracted a great deal of attention as integrated on-chip power sources due to their high theoretical power densities. Unfortunately, the costs of these devices have been rather high. This is partially due to the involved clean-room processes, but also due to the fact that these devices generally rely on expensive precious-metals such as Pd and Pt. Therefore we developed a novel integrated FC type accumulator that is based on non-precious-metals only. The key component of the presented accumulator is its alkaline polymer electrolyte membrane that allows not only the usage of a low-cost AB₅ type hydrogen storage electrode, but also the usage of La_0.6Ca_0.4CoO₃ as a precious-metal free bifunctional catalyst for the air-breathing electrode. Additionally the presented design requires only comparatively few cleanroom processes which further reduces the overall production costs. Although abdicating precious-metals, the presented accumulator shows an open circuit voltage of 0.81 V and a maximum power density of 0.66 mW cm⁻² which is comparable or even superior to former precious-metal based cells.     

Frequency of correctness versus average polynomial time

We prove that every distributional problem solvable in polynomial time on the average with respect to the uniform distribution has a frequently self-knowingly correct polynomial-time algorithm.     

Bulk Sediment and Diatom Silica Carbon Isotope Composition from Coastal Marine Sediments off East Antarctica

Organic carbon occluded in diatom silica is assumed to be protected from degradation in the sediment. δ¹³C from diatom carbon (δ¹³C_(diatom)) therefore potentially provides a signal of conditions during diatom growth. However, there have been few studies based on δ¹³C_(diatom). Numerous variables can influence δ¹³C of organic matter in the marine environment (e.g., salinity, light, nutrient and CO₂ availability). Here we compare δ¹³C_(diatom) and δ¹³C_(TOC) from three sediment records from individual marine inlets (Rauer Group, East Antarctica) to (i) investigate deviations between δ¹³C_(diatom) and δ¹³C_(TOC), to (ii) identify biological and environmental controls on δ¹³C_(diatom) and δ¹³C_(TOC), and to (iii) discuss δ¹³C_(diatom) as a proxy for environmental and climate reconstructions. The records show individual δ¹³C_(diatom) and δ¹³C_(TOC) characteristics, which indicates that δ¹³C is not primarily controlled by regional climate or atmospheric CO₂ concentration. Since the inlets vary in water depths offsets in δ¹³C are probably related to differences in water column stratification and mixing, which influences redistribution of nutrients and carbon within each inlet. In our dataset changes in δ¹³C_(diatom) and δ¹³C_(TOC) could not unequivocally be ascribed to changes in diatom species composition, either because the variation in δ¹³C_(diatom) between the observed species is too small or because other environmental controls are more dominant. Records from the Southern Ocean show depleted δ¹³C_(diatom) values (1–4 ‰) during glacial times compared to the Holocene. Although climate variability throughout the Holocene is low compared to glacial/interglacial variability, we find variability in δ¹³C_(diatom), which is in the same order of magnitude. δ¹³C of organic matter produced in the costal marine environment seems to be much more sensitive to environmental changes than open ocean sites and δ¹³C is of strongly local nature.