159 research outputs found

    Studies in molecular structure, symmetry and conformation VI. Crystal and molecular structure of 1-aminocyclopentane carboxylic acid monohydrate

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    1-aminocyclopentane carboxylic acid monohydrate is monoclinic: space group P 2 1 / c , a = 11·24, b = 6·27, c = 11·22 Å and β = 97·6 °. The crystal structure was solved by the symbolic addition method and refined to an R factor of 12·1%. The cyclopentane ring is disordered; one of the carbon atoms exists in two alternative sites, leading to two possible conformations both of which are of the envelope type.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44835/1/10870_2005_Article_BF01245860.pd

    The Threads of Biosystems Engineering

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    The core concepts, or threads, of Biosystems Engineering (BSEN) are variously understood by those within the discipline, but have never been unequivocally defined due to its early stage of development. This makes communication and teaching difficult compared to other well established engineering subjects. Biosystems Engineering is a field of Engineering which int egrates engineering science and design with applied biological, environmental and agricultural sciences. It represents an evolution of the Agricultural Engineering discipline applied to all living organisms not including biomedical applications. The basic key element for the emerging EU Biosystems Engineering program of studies is to ensure that it offers essential minimum fundamental engine ering knowledge and competences . A core curriculum developed by Erasmus Thematic Networks is used as benchmark for Agr icultural and Biosystems Engineering studies in Europe. The common basis of the core curriculum for the discipline across the Atlantic , including a minimum of competences comprising the Biosystems Engineering core competencies, has been defined by an Atlan tis project , but this needs to be taken further by defining the threads linking courses together. This paper presents a structured approach to define the Threads of BSEN . The definition of the mid-level competences and the associated learning outcomes has been one of the objectives of the Atlantis programme TABE.NET. The mid-level competences and learning outcomes for each of six specializations of BSEN are defined while the domain-specific knowledge to be acquired for each outcome is proposed. Once the proposed definitions are adopted, these threads will be available for global development of the BSEN

    Novel INS/GPS Fusion Architecture for Aircraft Navigation

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    In this paper, we address the issue of aircraft navigational state estimation from the perspective of (i) aircraft attitude estimation, also called as the attitude heading reference system (AHRS), and (ii) estimating the full inertial solution of the aircraft (position, velocity & attitude), also known as inertial navigation system-global positioning system (INS/GPS) fusion, in the presence of accelerometer and gyroscopic bias. A suite of nonlinear filters; two Kalman filter (KF) based — extended and unscented Kalman filter (EKF, UKF) and a non-KF based filter that is the nonlinear complementary filter (NCF) on the SO(3) group, are studied and evaluated for the AHRS. In this paper we propose a novel INS/GPS fusion architecture that demonstrated a significant improvement in performance over the conventional KF based schemes, in tests done on realistic simulated aircraft data. In the proposed architecture, the attitude estimation is decoupled from the position and velocity estimation, by exploiting the NCF as it is known for its superior attitude and gyroscopic bias estimation performance. The position and velocity estimation is carried out by a conventional EKF. The crucial difference between KF based schemes and the NCF for attitude estimation is in the generation of the measurement set, which involves trigonometric inverses and are susceptible to singularities for KF based schemes, which the NCF avoids. Furthermore, the NCF algorithm is faster and computationally more efficient than a KF algorithm scheme since the NCF does not involve the computation of matrix inverses like KF based schemes

    Oxychlorination of some lower aliphatic-hydrocarbons

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    Electroflotation - a review

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    DIRECT OXYCHLORINATION OF ETHYLENE TO VINYL-CHLORIDE MONOMER

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    PYROMETALLURGICAL PROCESSES FOR THE SEPARATION OF HAFNIUM FROM ZIRCONIUM

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