A new acceleration-based methodology for micro/meso-scale machine tool performance evaluation

Micro-machining and micro/meso-scale machine tools (mMTs) use substantially different motion parameters than those used at the macro-scale. A new acceleration-based mMT performance evaluation methodology is developed based on an assessment of motion parameters, and in particular, unique acceleration requirements at the micro-scale. Performance evaluations using the new methodology are carried out on two prototype mMTs. Following errors are found for the most part to increase linearly with acceleration. The closed loop bandwidth is found to be the current major factor affecting acceleration capability for the machines tested. A linear model linking servo-update frequency, closed-loop bandwidth, acceleration and following error is proposed. The model results provide a basis for prescribing maximum acceleration values to maintain 10⁻²–10⁻³ relative accuracy. Future mMT component performance requirements are explored.     

Set-membership adaptive equalization and an updator-sharedimplementation for multiple channel communications systems

This paper considers the problems of channel estimation and adaptive equalization in the novel framework of set-membership parameter estimation. Channel estimation using a class of set-membership identification algorithms known as optimal bounding ellipsoid (OBE) algorithms and their extension to tracking time-varying channels are described. Simulation results show that the OBE channel estimators outperform the least-mean-square (LMS) algorithm and perform comparably with the RLS and the Kalman filter. The concept of set-membership equalization is introduced along with the notion of a feasible equalizer. Necessary and sufficient conditions are derived for the existence of feasible equalizers in the case of linear equalization for a linear FIR additive noise channel. An adaptive OBE algorithm is shown to provide a set of estimated feasible equalizers. The selective update feature of the OBE algorithms is exploited to devise an updator-shared scheme in a multiple channel environment, referred to as updator-shared parallel adaptive equalization (USHAPE). U-SHAPE is shown to reduce the hardware complexity significantly. Procedures to compute the minimum number of updating processors required for a specified quality of service are presented     

Randomized, double-blind placebo-controlled trial of coenzyme Q10 in patients with acute myocardial infarction

Adherence with inhaled beta-agonists and corticosteroids in 24 asthmatic children was tracked over 3 months utilizing the metered-dose inhaler chronolog (MDIC). Patients seldom took all of their medications as prescribed, and failed to take any inhaled corticosteroid doses on a median of 41.8% of days or inhaled beta-agonists on 28.1% of days despite prescribed daily use. Medication nonadherence was correlated with lower levels of asthma knowledge (Asthma Knowledge Questionnaire) and family dysfunction (Family Assessment Device), but not child behavior disorder (Child Behavior Checklist). Patients tended to dramatically over-report medication use. Improved identification of the markers of nonadherence can directly facilitate more efficient targeting of behavioral interventions, resulting in improved adherence, better illness control, and less requirement of urgent medication intervention.     

Effect of operating current dependent series resistance on the fill factor of a solar cell

The fill factor of a solar cell depends upon the series resistance, reverse saturation current, diode quality factor, operating current and voltage. Since the series resistance itself depends upon the operating current (or voltage), it makes the evaluation of fill factor very complicated. In this paper, we have evaluated the fill factor of a solar cell, taking into account operating current dependence of the series resistance.     

T lymphocytes with a normal ADA gene accumulate after transplantation of transduced autologous umbilical cord blood CD34+ cells in ADA-deficient SCID neonates

Adenosine deaminase-deficient severe combined immunodeficiency was the first disease investigated for gene therapy because of a postulated production or survival advantage for gene-corrected T lymphocytes, which may overcome inefficient gene transfer. Four years after three newborns with this disease were given infusions of transduced autologous umbilical cord blood CD34+ cells, the frequency of gene-containing T lymphocytes has risen to 1-10%, whereas the frequencies of other hematopoietic and lymphoid cells containing the gene remain at 0.01-0.1%. Cessation of polyethylene glycol-conjugated adenosine deaminase enzyme replacement in one subject led to a decline in immune function, despite the persistence of gene-containing T lymphocytes. Thus, despite the long-term engraftment of transduced stem cells and selective accumulation of gene-containing T lymphocytes, improved gene transfer and expression will be needed to attain a therapeutic effect.     

Interval reliability of a two-unit stand-by redundant system

This brief note obtains expressions for Interval Reliability of a 2-unit stand-by repairable system by using the regenerative point technique of the Markov Renewal Process.     

Operation of poly bipolar transistors near liquid-heliumtemperatures (9 K)

Operation of bipolar transistors with poly emitters with current gain β>25 at 77 K and β>3 at 9 K has been demonstrated. In the temperature range of 300 K to 9 K, the plot of β vs. temperature (T) exhibits a minimum at T equal to 40 K: decreasing monotonically from 300 K to 40 K, remaining unchanged between 40 K to 30 K, and increasing slightly from 30 K to 9 K. This behavior is attributed to freezeout of acceptor impurities in the base for T<40 K     

Über die Basizität flüssiger Schlacken der Systeme CaO–SiO2 und CaO–Al2O3

EMK-Messungen mit einer Diffusionszelle an flüssigen Schlacken der Systeme CaO–Al₂O₃ und CaO–SiO₂ bei 1600°C. EMK und Sulfidkapazität zeigen lineare Abhängigkeit. EMK-Werte können als relatives Basizitätsmaß gewertet werden.