The efficient substitution of sucrose by a sweetener in beverages requires the application of some sensory techniques. First, one must determine the concentrations of the sweeteners under study, equivalent in sweetness to the ideal sucrose concentration. In addition, it is fundamental to determine which is most similar to sucrose. The objectives of this study were to determine the ideal sweetness for espresso coffee and the equivalent concentrations in sweetness of different sweeteners, as well as characterise the time–intensity profile of each sweetener in relation to sweetness. The sweeteners evaluated were sucralose, aspartame, neotame, a cyclamate/saccharin mixture (2:1) and stevia. The sucrose concentration considered ideal by consumers was 12.5% (w/v), and the equivalent concentrations of the sweeteners were 0.0159% for sucralose, 0.0549% for aspartame, 0.0016% for neotame, 0.0359% for the cyclamate/saccharin mixture and 0.0998% for stevia. The time–intensity analysis indicated that possibly the sweeteners neotame, aspartame and sucralose would be the best substitutes for sucrose. 相似文献
High-strength steels are used to increase the load carrying capacity of components. However, to guarantee a safe design, it is also necessary to combine high strength with adequate fracture toughness. In this paper, fracture toughness of three high-strength steels with yield strengths ranging from 460 to 890 MPa has been studied at very low temperatures. Taking into account experimental evidence, a new mechanism of cleavage at very low temperatures is proposed. This mechanism considers the possibility of reaching the ideal strength (the stress at which the lattice of a single crystal losses its stability) in the immediate vicinity of the fatigue crack tip. Moreover, a computational model able to calculate the external load needed to produce a catastrophic failure of these steels has been developed. 相似文献
All image systems cause a blurring of the scene radiance field during image acquisi- tion. Accurate characterization of this blurring is referred to as the modulation transfer function (MTF)[1]. The MTF is a fundamental imaging system design specification and system quality metric often used in remote sensing. It results from the cumulative effects of the instrumental optics (diffraction, aberrations, focusing error), integration on a pho- tosensitive surface, charge diffusion along the arra… 相似文献
Calculating caloric properties from a thermal equation of state requires information such as isobaric heat capacities in the ideal-gas state as a function of temperature. In this work, values for the parameters of thecp0
correlation proposed by Aly and Lee were newly determined for 21 pure gases which are compounds of natural gas mixtures. The values of the parameters were adjusted to selectedcp0
data calculated from spectroscopic data for temperatures ranging from 10 to 1000 K. The data sources used are discussed and compared with literature data deduced from theoretic models and caloric measurements. The parameters presented will be applied in a current GERG project for evaluating equations of state (e.g., the AGA 8 equation) for their suitability for calculating caloric properties. 相似文献
This paper presents a project undertaken for the European Space Agency (ESA). The project is developing a knowledge based system for planning and scheduling of activities for spacecraft assembly, integration and verification (AIV). The system extends to the monitoring of plan execution and the plan repair phases.
The objectives of the contract are to develop an operational kernel of a planning, scheduling and plan repair tool, called OPTIMUM-AIV, and to provide facilities which will allow individual projects to customize the kernel to suit its specific needs. The kernel shall consist of a set of software functionalities for assistance in the initial specification of the AIV plan, in the verification and generation of valid plans and schedules for the AIV activities, and in interactive monitoring and execution problem recovery for the detailed AIV plans. Embedded in OPTIMUM-AIV are external interfaces which allow integration with alternative scheduling systems and project databases.
The current status of the OPTIMUM-AIV project, as of May 1991, is that the architectural design of the system has been agreed on by ESTEC/ESA and detailed design and implementation is now underway, expecting a final delivery in October of 1991. 相似文献
The aim of this paper is to propose a new way to deal with observability of systems governed by ODEs, in a more general setting than the standard output equation.The primary finding is that observability over a time horizon reduces to single-valuedness of the vertical section of a set we name the observability kernel.The latter consists of the viability kernel of the output domain under the augmented system.The approach may be used either for global or local observability,to which available results on single-valuedness of multifunctions shall be applied in order to get necessary and/or sufficient characterizing conditions.Several examples are provided in order to illustrate the method. 相似文献