Acetaldehyde in Mineral Water Stored in Polyethylene Terephthalate (PET) Bottles: Odour Threshold and Quantification

The use of PET bottles for packaging soft drinks and mineral waters is still growing world wide. The production process for these bottles is improving constantly. These improvements are focussed on bottles with better barrier properties, higher inertness and higher heat stability. One of the factors determining the quality of PET bottles is the release of acetaldehyde into the product during storage. A literature survey was conducted on the odour and taste detection threshold of acetaldehyde in water. A method is described to rapidly determine the concentration of acetaldehyde in water up to a level of 1 μg/l. This method was used to determine the concentration of acetaldehyde in mineral water during storage in PET bottles. In still water no acetaldehyde could be found, whereas the concentration of acetaldehyde in carbonated mineral water increased steadily upon storage. Model experiments were performed to find an explanation.     

On a new formal proof model for RFID location privacy

We discuss a recently proposed formal proof model for RFID location privacy. We show that protocols which intuitively and in several other models are considered not to be location private, are provably location private in this model. Conversely, we also show that protocols which obviously are location private, are not considered location private in this model.Specifically, we prove a protocol in which every tag transmits the same constant message to not be location private in the proposed model. Then we prove a protocol in which a tag's identity is transmitted in clear text to be weakly location private in the model.     

Variant-based cost estimation based on Information Management

Based on the product information structure related to the Manufacturing Engineering Reference Model, a method for variant-based cost estimation is proposed. The structure defines a product in terms of elements and their relations. The elements and their properties constitute product characteristics that can be used to compare products. For proper use in different engineering processes, the product characteristics are related to the four cost drivers - geometry, material, processes and production planning. The main advantage of the proposed method is a more flexible way of defining and valuing product characteristics without the use of rigid product classes and codes.     

Modeling water sorption dynamics of cellular solid food systems using free volume theory

Water sorption and dynamical properties of bread crust were studied using gravimetric sorption experiments. Water uptake and loss were measured while relative humidity (RH) was step-wise in- or decreased. Experimental results were compared with Fickian diffusion models and empirical models like the exponential and power-law model. From comparison of experimental sorption curves and the power-law model for short times it followed for all bread crust that the diffusional coefficient n is close to one. It turned out that this is not due to so-called case II diffusion and water transport that is limited by relaxation of the solid material but due to the fact that RH did not instantaneously but gradually increased to the set value.Sorption curves of isotherm experiments could be best described by the Fickian diffusion model for low RH and by the exponential model for large RH. Transport rates depend on moisture content and show a maximum around RH = 0.7, corresponding to a water mass fraction ω₁ = 0.12. Diffusion rates could be well described by free volume theory up to the maximum, but this theory could not explain the strong decrease at higher ω₁. Indications for a local glass-rubber transition at room temperature were found near a water mass fraction ω₁ ≈ 0.09. This corresponds very well to the start of the crisp–non-crisp transition as measured by a sensory panel, but not to the glass-rubber transition at ω₁ ≈ 0.12 as measured by other techniques like Differential Scanning Calorimetry. So it seems that more than one glass-rubber like transitions may be important to describe the properties of heterogeneous cellular food systems.     

Variables influencing food perception reviewed for consumer-oriented product development

Consumer wishes have to be translated into product characteristics to implement consumer-oriented product development. Before this step can be made, insight in food-related behavior and perception of consumers is necessary to make the right, useful, and successful translation. Food choice behavior and consumers' perception are studied in many disciplines. Models of food behavior and preferences therefore were studied from a multidisciplinary perspective. Nearly all models structure the determinants related to the person, the food, and the environment. Consequently, the overview of models was used as a basis to structure the variables influencing food perception into a model for consumer-oriented product development. To this new model, referred to as food perception model, other variables like time and place as part of consumption moment were added. These are important variables influencing consumers' perception, and therefore of increasing importance to consumer-oriented product development nowadays. In further research, the presented food perception model is used as a tool to implement successful consumer-oriented product development.     

仲丁醇—水体系的汽液相平衡

用静态法测定了仲丁醇—水体系在0.5MPa压力下的恒压气液平衡数据。用Heringon方法检验数据的热力学一致性,表明实测数据可靠。作者探讨了NRTL、UNIQUAC、ASOG和UNIFAC模型对该体系的关联和予测,并对各方程的拟合结果进行了分析。     

Design of an analytic constrained predictive controller using neural networks

This paper shows how the solution of the standard predictive control problem can be recast as a continuous function of the state, the reference signal, the noise and the disturbances, and hence can be approximated arbitrarily closely by a feed-forward neural network. The existence of such a continuous mapping eliminates the need for linear independency of the active constraints, and therefore the resulting analytic constrained predictive controller will combine constraint handling with speed while being applicable to fast and complex control systems with many constraints. The effectiveness of the proposed controller design methodology is shown for a simulation example of an elevator model and for a real-time laboratory inverted pendulum system.     

Development of a Hypersensitive Periodate‐Cleavable Amino Acid that is Methionine‐ and Disulfide‐Compatible and its Application in MHC Exchange Reagents for T Cell Characterisation

Incorporation of cleavable linkers into peptides and proteins is of particular value in the study of biological processes. Here we describe the synthesis of a cleavable linker that is hypersensitive to oxidative cleavage as the result of the periodate reactivity of a vicinal amino alcohol moiety. Two strategies directed towards the synthesis of a building block suitable for solid‐phase peptide synthesis were developed: a chemoenzymatic route, involving L ‐threonine aldolase, and an enantioselective chemical route; these led to α,γ‐diamino‐β‐hydroxybutanoic acids in diastereoisomerically mixed and enantiopure forms, respectively. Incorporation of the 1,2‐amino alcohol linker into the backbone of a peptide generated a conditional peptide that was rapidly cleaved at very low concentrations of sodium periodate. This cleavable peptide ligand was applied in the generation of MHC exchange reagents for the detection of antigen‐specific T cells in peripheral blood cells. The extremely low concentration of periodate required to trigger MHC peptide exchange allowed the co‐oxidation of methionine and disulfide residues to be avoided. Conditional MHC reagents hypersensitive to periodate can now be applied without limitations when UV irradiation is undesired or less practical.     

Influence of Matrix Ductility and Fibre Architecture on the Repeated Impact Response of Glass-Fibre-Reinforced Laminated Composites

This paper describes the results of falling weight impact tests on glass-fibre-reinforced laminates. The test program consisted of (i) falling weight impact tests for the determination of the penetration energy and the influence of laminate construction on damage development and (ii) repeated falling weight impact tests for the determination of the impact fatigue lifetime and damage development under repeated impact conditions at sub-penetration energy levels. The objective of this work is to compare the impact behaviour of cross-ply laminates based on a brittle unsaturated polyester resin and a more ductile vinyl ester resin system and two types of glass reinforcement, i.e. woven- and multiaxial non-crimp fabric. The penetration energy of the various composite laminates appeared to be mainly influenced by the type of reinforcement, whereas damage development during (repeated) impact is strongly influenced by both fibre architecture and resin. No significant effect of the different material parameters investigated on the number of impacts to penetration (impact fatigue lifetime) is observed. Especially when the repeated impact energy is normalised with respect to the penetration energy, all laminates showed similar behaviour.     

Designing a cost-effective CO2 storage infrastructure using a GIS based linear optimization energy model

Large-scale deployment of carbon capture and storage needs a dedicated infrastructure. Planning and designing of this infrastructure require incorporation of both temporal and spatial aspects. In this study, a toolbox has been developed that integrates ArcGIS, a geographical information system with spatial and routing functions, and MARKAL, an energy bottom-up model based on linear optimization. Application of this toolbox led to blueprints of a CO₂ infrastructure in the Netherlands. The results show that in a scenario with 20% and 50% CO₂ emissions reduction targets compared to their 1990 level in respectively 2020 and 2050, an infrastructure of around 600 km of CO₂ trunklines may need to be built before 2020. Investment costs for the pipeline construction and the storage site development amount to around 720 m€ and 340 m€, respectively. The results also show the implication of policy choices such as allowing or prohibiting CO₂ storage onshore on CO₂ Capture and Storage (CCS) and infrastructure development. This paper illustrates how the ArcGIS/MARKAL-based toolbox can provide insights into a CCS infrastructure development, and support policy makers by giving concrete blueprints over time with respect to scale, pipeline trajectories, and deployment of individual storage sites.