Comparison of nonlinear dynamic inversion and inverse simulation

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Craft beer: penetrating a niche market

Purpose – The purpose of this paper is to examine the underexplored niche market potential of craft beer, especially as it may relate to independent food and beverage operations, as a means of gaining competitive advantage. Design/methodology/approach – Data were collected through the distribution of a survey instrument to craft beer and home brewers, designed to assess the demographic profile, purchasing/restaurant selection, and decision behavior of this group and assess the likelihood of their future behavioral intentions toward continued participation in the craft beer segment. Findings – The paper reveals that craft beer and micro brew pub success has been driven by the home brew movement and continues to gain market share at the expense of broad line food service and macro beer producers. The demographic profile of this group shows age range, income, and educational levels sufficient to drive continued growth. The high satisfaction and likelihood to recommend scores support this assessment. Research limitations/implications – The sample is limited to members of the Brewers Association, the American Home Brewers Association, and craft beer enthusiasts known to members of the organization. Additionally, the survey was administered electronically limiting participation to people comfortable with this medium. Practical implications – F&B operators who demonstrate commitment to craft beer through server education, beverage list commitment, and supporting events can achieve market differentiation and dominance within the niche; leading ultimately to competitive advantage. Originality/value – This research sheds light on underexplored areas of craft beer and the opportunity for independent F&B operators to identify and penetrate an increasingly important niche market, which to date has been viewed primarily from the perspective of microbrew pubs

Work Towards The Total Synthesis Of Patchouli Alcohol And Approaches To Cycloseychellene

The synthesis of polycyclic compounds usually requires numerous synthetic operations in order to construct the desired carbon skeletons. A simple procedure termed a bicycloannulation allows for the generation of one of these ring systems in one synthetic operation. The tricyclo 3.2.1.0(\u272,7) octane ring system incorporates a two carbon bridge cross a cyclohexane ring which includes at one end a cyclopropane ring. This tricyclic carbon skeleton is a highlighting feature of a number of terpenoids, including the sesquiterpene cycloseychellene. Beginning with a substituted cyclohexenone, the bicycloannulation allows for the construction of all but one of the rings in this tetracyclic sesquiterpene. A number of approaches for the formation of the remaining ring are discussed.;Liquid-ammonia reduction of the tricyclo 3.2.1.0(\u272,7) octane ring system allows easy access into the bicyclo 2.2.2 octane ring series. With the use of this technique, work towards the total synthesis of patchouli alcohol is discussed as well as a formal synthesis of this commercially valuable compound

Crystallization of high silica molecular sieves

Tetraethyl silicate has been hydrolysed under controlled conditions to produce "clear" silicate sols. An investigation of these sols by both trimethylsilylation and reaction with molybdic acid solution did not reveal any major difference between these sols and those produced from fumed silica. However these sols remain clear when heated to temperatures normally used in the synthesis of high silica molecular sieves (353K to 473K) and do not separate into solution plus solid gel as is the case with sols normally used in molecular sieve synthesis. New methods to follow the growth of zeolite crystals have been developed. Since there is no solid gel phase the zeolite crystals can be recovered by filtration and then weighed. Thus crystallization can be followed directly by mass growth measurements. Crystallization from the "clear" sols can also be followed by silicate analysis of the solution phase. These methods are not appropriate for crystallization from gels. Reaction mixtures have been sealed inside glass capillary tubes and the crystals grown at different temperatures. The crystal growth of individual crystals can then be followed by optical microscopy. The effects of temperature and chemical composition on the crystallization of ZSM -5 type zeolites has been examined. Apparent activation energies of growth for the different crystal faces have been calculated from Arrhenius plots. Factors which influence the size and shape of the crystals have been determined. Conditions for the growth of relatively large crystals of ZSM -5 have been established. Similar conditions are found to produce larger crystals of some other high silica molecular sieves (e.g. EU -1, ZSM -39 and ZSM -48). The crystallization of silicalite -1 at 368K from reaction mixtures with the composition 1Na20 20SiO2 1960H2O 80Et0H 2TPABr has been studied in detail, using thermal gravimetric analysis, scanning electron microscopy, X -ray powder diffraction, pH measurements and crystal mass measurements. The rate of linear crystal growth has been determined by measurement of the largest crystals at various stages of the crystallization. Nucleation curves have been calculated from the final crystal size distribution and the crystal growth curve. The crystal mass growth curve has also been calculated from the crystal growth curve data and the final crystal size distribution. The calculated mass growth curve is found to be in close agreement with the actual mass growth curve obtained experimentally

Derivative observations in Gaussian Process models of dynamic systems

Gaussian processes provide an approach to nonparametric modelling which allows a straightforward combination of function and derivative observations in an empirical model. This is of particular importance in identification of nonlinear dynamic systems from experimental data. 1)It allows us to combine derivative information, and associated uncertainty with normal function observations into the learning and inference process. This derivative information can be in the form of priors specified by an expert or identified from perturbation data close to equilibrium. 2) It allows a seamless fusion of multiple local linear models in a consistent manner, inferring consistent models and ensuring that integrability constraints are met. 3) It improves dramatically the computational efficiency of Gaussian process models for dynamic system identification, by summarising large quantities of near-equilibrium data by a handful of linearisations, reducing the training size - traditionally a problem for Gaussian process models

A Comparison of Inverse Simulation-Based Fault Detection in a Simple Robotic Rover with a Traditional Model-Based Method

Robotic rovers which are designed to work in extra-terrestrial environments present a unique challenge in terms of the reliability and availability of systems throughout the mission. Should some fault occur, with the nearest human potentially millions of kilometres away, detection and identification of the fault must be performed solely by the robot and its subsystems. Faults in the system sensors are relatively straightforward to detect, through the residuals produced by comparison of the system output with that of a simple model. However, faults in the input, that is, the actuators of the system, are harder to detect. A step change in the input signal, caused potentially by the loss of an actuator, can propagate through the system, resulting in complex residuals in multiple outputs. These residuals can be difficult to isolate or distinguish from residuals caused by environmental disturbances. While a more complex fault detection method or additional sensors could be used to solve these issues, an alternative is presented here. Using inverse simulation (InvSim), the inputs and outputs of the mathematical model of the rover system are reversed. Thus, for a desired trajectory, the corresponding actuator inputs are obtained. A step fault near the input then manifests itself as a step change in the residual between the system inputs and the input trajectory obtained through inverse simulation. This approach avoids the need for additional hardware on a mass- and power-critical system such as the rover. The InvSim fault detection method is applied to a simple four-wheeled rover in simulation. Additive system faults and an external disturbance force and are applied to the vehicle in turn, such that the dynamic response and sensor output of the rover are impacted. Basic model-based fault detection is then employed to provide output residuals which may be analysed to provide information on the fault/disturbance. InvSim-based fault detection is then employed, similarly providing \textit{input} residuals which provide further information on the fault/disturbance. The input residuals are shown to provide clearer information on the location and magnitude of an input fault than the output residuals. Additionally, they can allow faults to be more clearly discriminated from environmental disturbances