The impact of sugar and fat reduction on perception and liking of biscuits

Reducing the fat and/or sugar content in biscuits can be a way to improve their nutritional composition. Seventy-nine consumers of biscuits were recruited to study the impact of these reductions on liking and perception. Four categories of products were selected from a wide range of biscuits available at the French market. Three to six variants of each type of biscuit were produced based on reduced content of sugar, fat or both. Consumers tested the samples under laboratory conditions (6 sessions), recording their liking during initial sessions and crispiness, sweetness and fat perception during latter sessions. Sugar-reduced biscuits were perceived as less sweet than standard biscuits at low reduction levels, whereas fat-reduced biscuits were perceived as less fatty than standard biscuits at higher reduction levels (except for one biscuit among the three biscuits studied). A reduction in the sugar content had no effect on perception of fat, whereas a reduction in the fat content sometimes induced a reduced sweetness perception. For most of the biscuits studied, the least appreciated variants were those perceived as (1) less sweet, (2) less sweet and less fatty or (3) less sweet and less crispy than standard biscuits. Moreover, the variants only perceived as less fatty were not significantly disliked. These results suggest that from a sensory point of view, it is more acceptable to reduce the fat than the sugar content in biscuits, at least when products are not perceived as being less sweet

La fossilisation des empreintes de pattes et autres traces biologiques : rôle du voile algaire et de la diagenèse précoce

In the inter/supratidal algal mats, the early diagenesis products a progressive induration. It is enough to preserve all the deformations affecting the mats, including footprints of vertebrates, tracks and burrows of small invertebrates, and physical actions (desiccation cracks)

The dot-depth and the polynomial hierarchy correspond on the delta levels

It is well-known that the Sigma_k- and Pi_k-levels of the dot-depth hierarchy and the polynomial hierarchy correspond via leaf languages. In this paper this correspondence will be extended to the Delta_k-levels of these hierarchies: Leaf^P(Delta_k^L) = Delta_k^p

Homoserine Lactone as a Structural Key Element for the Synthesis of Multifunctional Polymers

The use of bio-based building blocks for polymer synthesis represents a milestone on the way to “green” materials. In this work, two synthetic strategies for the preparation of multifunctional polymers are presented in which the key element is the functionality of homoserine lactone. First, the synthesis of a bis cyclic coupler based on a thiolactone and homoserine lactone is displayed. This coupler was evaluated regarding its regioselectivity upon reaction with amines and used in the preparation of multifunctional polymeric building blocks by reaction with diamines. Furthermore, a linear polyglycidol was functionalized with homoserine lactone. The resulting polyethers with lactone groups in the side chain were converted to cationic polymers by reaction with 3-(dimethylamino)-1-propylamine followed by quaternization with methyl iodide

Experimental Simulation of the Human Respiration

In this paper, we present a new mobile respiration simulation system (RSS), which can be connected to existing thermal manikins. With the objective to simulate the human respiration process as realistic as possible, the system was validated on the basis of literature data and results obtained from human subject tests. The RSS reproduces realistic respiration cycles characterized by a sine wave of a typical normal breathing flow rate. The provided flow rates as well as the breathing frequency – representing the time of inhalation and exhalation – were verified by literature values. Since the new system additionally allows to enrich the exhaled air with carbon dioxide (CO2), experimental studies addressing the indoor air quality are also feasible. Here, the amount of CO2 emitted by the RSS corresponds to the average amount of CO2 exhaled by test persons. In addition, the flow characteristics occurring in a human nose are simulated using a self-developed facial mask, in combination with the new system. The result is a breathing thermal manikin based on a mobile respiration simulation system, which can easily be connected to heated passenger models. Accordingly, the system can be installed at any seat within a passenger compartment. This offers the advantage of individually defining the location of the manikin, which can effortlessly be adapted during a measurement campaign. Therefore, the system especially suitable for studies addressing the performance of ventilation systems in passenger compartments and indoor environments

Impact of Non-Occupied Seats on the Thermal Comfort in Long-Range Aircraft for Novel Ventilation Concepts

Novel ventilation systems for aircraft cabins have attracted the attention of scientists and aircraft manufacturers during the last years. Previous studies demonstrate the potential of energy saving as well as a achieving a higher level of thermal comfort in a single aisle aircraft. To allow for a greener and smarter testing of novel ventilation concepts for future long-range airliners, a full-scale twin aisle cabin mock-up with thermodynamically realistic boundary conditions by means of temperature-controlled fuselage elements was developed at the German Aerospace Center (DLR) in Göttingen. Temperature controlled thermal manikins allow to simulate the heat release and obstruction of real passengers. In this study, ceiling-based ventilation concepts were investigated experimentally with regard to incompletely occupied cabins, which are rather the rule than the exception (passenger load factor 75 to 90%, and even much less during the present pandemic time). Changes of the horizontal temperature distribution by switching off thermal manikins on selected seats for different flight phases were analysed using high-resolution local measurement probes as well as infrared cameras. A comparison with results of non-occupied seats in a single aircraft cabin will be conducted using previous studies and conclusions on the robustness of the ceiling-based concepts will be drawn

Low-cost Thermal Manikin - A Competitive Instrument to Simulate Thermal Loads and to Determine Thermal Passenger Comfort

A low-cost and practicable measurement instrument which allows the simulation of the heat loads and the obstruction of a human passenger, while simultaneously determining the thermal comfort, is highly desirable. At the DLR, a TM was developed which meets these requirements. The TM reveals a simplified, however, realistic shape and heat load of a human body. Furthermore, we defined a process chain to calibrate the TM in order to use it as an instrument for evaluating the thermal passenger comfort. However, the TM is continuously being developed further. Current projects address the topics of dimensionless characterization of the TM with the objective to identify the physical quantities which determine thermal comfort

Experimental study of the indoor aerosol-dynamics for a low-momentum ventilation system with an air purifier unit

We present an experimental study on the aerosol-dynamics within a test setup representing a class or conference room situation. To ensure realistic flow patterns, the blockage and heat release of the persons are simulated using 18 thermal manikins. The aerosol source is realized by a generator, attached to a thermal manikin, providing a realistic exhalation of artificial saliva. Two different ventilation scenarios are studied regarding aerosol concentration distribution and removal-efficiency. Additionally, the influence of a mask attached to the source and the effect of a moving person on the resulting aerosol concentrations are investigated. Time and spatially resolved concentrations are measured using 61 particulate matter sensors, installed on three height levels. The ventilation scenarios comprise window opening and a lowmomentum ventilation concept, where the air is extracted underneath the ceiling and reenters purified (HEPA14) on floor level. Each of the examined counter measures (open-window, low-momentum ventilation and mask) resulted in a significant lower particle concentration compared to the reference scenario. The low-momentum ventilation with an air purifier unit provided the best aerosol removal-efficiency with a decrease in concentration of up to 96%, followed by the window opening with 60%. The buoyancy flow induced by the heat loads and the resulting flow field caused by the lowmomentum ventilation concept lead to well-directed particle transport towards the ceiling. Consequently, a large amount of aerosol was extracted and filtered by the ventilation system resulting in lower particle concentrations. However, local concentrations were strongly depended on the position of the aerosol source

Micro-Jet Ventilation – a Novel Ventilation Concept for long-range Aircraft Cabins

Micro-Jet Ventilation (MJV), known from ventilation systems in trains, was experimentally investigated under static flight conditions in a full-scale twin-aisle cabin mock-up as part of the Clean-Sky 2 Joint Undertaking project ADVENT. A jacket cooling system was used to investigate ventilation systems for aircraft cabins with thermodynamically realistic boundary conditions. Temperature-controlled thermal manikins (TMs) make it possible to simulate the heat dissipation and obstruction of real passengers. In this study, six different modifications of MJV with different air inlet configurations are analyzed to determine the optimal parameters for thermal comfort and energy savings. Fluid temperatures as well as velocities in the vicinity of the TMs were investigated using high-resolution local probes. An evaluation of the various MJV configurations was performed based on heat removal efficiency, thermal comfort parameters, and tracer gas analysis. The study clearly shows the near-optimal comfort parameters of two MJV configurations for future aircraft cabins