Closed-form solutions for linear regulator design of mechanical systems including optimal weighting matrix selection

Vibration in modern structural and mechanical systems can be reduced in amplitude by increasing stiffness, redistributing stiffness and mass, and/or adding damping if design techniques are available to do so. Linear Quadratic Regulator (LQR) theory in modern multivariable control design, attacks the general dissipative elastic system design problem in a global formulation. The optimal design, however, allows electronic connections and phase relations which are not physically practical or possible in passive structural-mechanical devices. The restriction of LQR solutions (to the Algebraic Riccati Equation) to design spaces which can be implemented as passive structural members and/or dampers is addressed. A general closed-form solution to the optimal free-decay control problem is presented which is tailored for structural-mechanical system. The solution includes, as subsets, special cases such as the Rayleigh Dissipation Function and total energy. Weighting matrix selection is a constrained choice among several parameters to obtain desired physical relationships. The closed-form solution is also applicable to active control design for systems where perfect, collocated actuator-sensor pairs exist

Study of advanced fuel system concepts for commercial aircraft and engines

The impact on a commercial transport aircraft of using fuels which have relaxed property limits relative to current commercial jet fuel was assessed. The methodology of the study is outlined, fuel properties are discussed, and the effect of the relaxation of fuel properties analyzed. Advanced fuel system component designs that permit the satisfactory use of fuel with the candidate relaxed properties in the subject aircraft are described. The two fuel properties considered in detail are freezing point and thermal stability. Three candidate fuel system concepts were selected and evaluated in terms of performance, cost, weight, safety, and maintainability. A fuel system that incorporates insulation and electrical heating elements on fuel tank lower surfaces was found to be most cost effective for the long term

The Expression of the Epithelial Blood-group Substances: Normal and Malignant Tissues

The blood-group isoantigens are macromolecules localized to the plasma membranes of certain epithelial tissues.2,11-15 These substances are not detectable on the epithelium once it has undergone malignant transformation.2,9,13 Results of this investigation have demonstrated that the loss of detectability of the blood-group isoantigens does not appear to be related to a "masking" effect by an increase in surface sialic acid. Using fluorescein-labeled lectins specific for sugar subunits which are components of the blood-group oligosaccharide chain, it was found that the malignant cells and cells of the para basal layer of normal oral epithelium had high levels of N-acetyl-D-glucosamine (GlcNAC), the subterminal sugar residue of the blood-group chain. The basal cells of normal epithelium and a minority of the malignant cells demonstrated levels of D-galactose-N-acetyl-D-galactosamine, which are the most proximal blood-group sugar subunits, as well as subunits of other membrane antigens. Our results indicate that malignant cells seem to be capable of synthesizing the blood-group oligosaccharide chains to the same level as the normal cells of the para basal layer of stratified squamous epithelium. This level is just subjacent to the terminal D-galactose residue of the blood-group precursor chain. Increased or decreased differentiation characteristics of squamous cell carcinomas did not alter the level of blood-group synthesis. However, there may be a correlation between the level of synthesis of these antigens and the ability of the cells to demonstrate motility and to proliferate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66719/2/10.1177_00220345800590112001.pd

Consensus on level descriptors for a functional children's eating and drinking activity scale

Aim: To agree wording of level descriptors for a measure of functional outcome of children's eating and drinking. Method: An online, modified Delphi method was used to gather feedback on current level descriptor wording and generate rewording suggestions. Thirty speech and language therapists, working in a variety of settings and geographical locations, were invited to be part of the Delphi expert panel. Content analysis was used to evaluate participants' comments and develop consensus level descriptors. Consensus for acceptable wording was set at 80% agreement. Face validity was assessed using 5-point Likert scales. Results: Nineteen expert speech and language therapists (median experience 18 years) completed round one; 15 out of 19 completed round two. Level descriptor rating reached 80% agreement in two rounds. Additionally, 93% of participants agreed the scale would accurately capture change in their setting, with 87% likely to use the scale in practice. Interpretation: This study has produced agreed wording for a functional measure of eating and drinking activity suitable for use with paediatrics feeding disorders, regardless of disease aetiology, presentation, age, or setting. Potential for widespread use is supported. Further evaluation of the tool's reliability and validity is required

Psalms on the Shannon: A Collection of Choral Pieces in the Irish Celtic Style

The Irish music tradition has a rich heritage ranging from ancient ballads to nineteenth-century dances. One area of Irish music, a subset of Celtic music in general, that has been somewhat underrepresented in modern times is Irish choral music. Scripturally-based choral singing has been part of the Irish tradition ever since medieval monks began Christianizing the Celts. Today, several choral groups in Ireland are working to revive the art of Celtic choral singing. This collection, presenting psalms set to choral music in the Irish style, is one modern composer’s endeavor to join the Irish choral genre, incorporating traditional harmonic elements and following a long-established line of psalm singing in Ireland. Portions of text are sung in both English and Irish

Use of soil moisture information in yield models

There are no author-identified significant results in this report

Blood group substances as differentiation markers in human dento-gingival epithelium

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65594/1/j.1600-0765.1987.tb02054.x.pd