Ball cocks for liquid abrasive media

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 6, pp. 8–9, June, 1991.     

A geometric view of conjugate priors

In Bayesian machine learning, conjugate priors are popular, mostly due to mathematical convenience. In this paper, we show that there are deeper reasons for choosing a conjugate prior. Specifically, we formulate the conjugate prior in the form of Bregman divergence and show that it is the inherent geometry of conjugate priors that makes them appropriate and intuitive. This geometric interpretation allows one to view the hyperparameters of conjugate priors as the effective sample points, thus providing additional intuition. We use this geometric understanding of conjugate priors to derive the hyperparameters and expression of the prior used to couple the generative and discriminative components of a hybrid model for semi-supervised learning.     

Magnetic Field Stabilization for Magnetically Shielded Volumes by External Field Coils

For highly sensitive magnetic measurements, e.g., a measurement of the neutron electric dipole moment (EDM), the magnetic field has to be stable in time on a level below picoTesla. One of several measures we employ to achieve this uses an external field coil system which can stabilize the ambient external field at a predefined value. Here we report on the construction and characterization of such a system in the magnetic test facility at PSI. The system actively stabilizes the field along the axis of the EDM experiment by means of four coils in a Helmholtz-like configuration. Additional coils serve to compensate for transverse ambient field components. Because of the long integration times in the EDM experiment (about 100 s or more) only slow disturbances have to be corrected for. The performance of the system has been measured using static and moving magnetic sources and suppression factors in excess of 200 have been observed.     

A personalized measure of thermal comfort for building controls

A personalized measure for thermal comfort has been applied for use in combination with smart controls for building automation. Using data from a field study, we first show the superiority of personalized measures for thermal comfort compared to standard non-adaptive methods. Based on this knowledge we describe a methodology, using logistic regression techniques, to convert user votes to a probability of comfort. We also describe the interface used to collect the votes. We show that, for a given subject, our thermal profile converges against the probabilities found in the field study. As a case study we implemented the measure in a control algorithm to control the shading devices. The results clarify the mode of action and also show the effectiveness of the method.     

Quantitative analysis of the in situ Fourier transform infrared absorption and emission spectrum of gas-phase SiO (Deltav = 1 and 2) produced in Si-N-O fiber growth

The in situ Fourier transform infrared (FT-IR) spectrum of gasphase SiO produced in silicon oxynitride fiber growth has been quantitatively analyzed. Both absorption and emission FT-IR spectra at a spectral resolution of 0.5 cm(-1) were produced from the reaction zone at 1450 degrees C. The fundamental and hot bands were observed with vibrational levels up to v = 7. For the purposes of quantitative analysis the individual vibration-rotation integrated line strengths for the three main isotopes,( 28)SiO,( 29)SiO, and( 30)SiO, were calculated based on ab initio quantum chemical calculations of the electric dipole moment function and the transition moment. Vibrational anharmonicity and Hermann-Wallis correction factors were also incorporated. From the line strengths at specific temperatures and the known Dunham coefficients, the absorbance spectrum was simulated with best fits giving the averaged SiO concentration in the 400 mm reaction zone of 1.0 x 10(17) molecules/cm(3). Such quantitative measurements demonstrate the power of in situ infrared (IR) spectroscopy combined with quantum chemical calculations. The rapid determination of synthetic calibration datasets for chemometric analysis can thus lead to correlation of gas-phase species concentrations with fiber growth properties and subsequently to real-time process control.     

Cutting edge acoustics. Non-invasive surgery using ultrasound

Focused ultrasound surgery is a procedure whereby high-power ultrasound is pinpointed into the body. At high enough intensities, the tissue at the focus can be thermally burned or mechanically destroyed. Tissue in front or behind the focus is not affected since the intensity is much lower. This results in less overall internal trauma; i.e., faster healing. The goal at the Focused Ultrasound Surgery Lab at Brigham and Women's Hospital in Boston, MA is to use this technique to non-invasively treat tumors. This could eliminate the need for surgically removing tissue, thus offering the patient a blood-free alternative. More importantly, it could offer a cure to those patients whose illness cannot be treated by traditional surgery. Time will tell what therapeutic ultrasound's impact will have in treating disease in the long term. Nevertheless, the medical profession's desire for less invasive treatments has grown tremendously. As a result, ultrasound's preliminary success indicates that using therapeutic ultrasound will increasingly benefit patients     

The yeast mic2 mutant is defective in the formation of mannosyl-diinositolphosphorylceramide

Three transmembrane glutamic acid residues play essential roles in the metal-tetracycline/H+ antiporter Tet(K) of Staphylococcus aureus [Fujihira et al., FEBS Lett. 391 (1996) 243-246]. In the putative hydrophilic loop region of the Tet(K) and Tet(L) proteins, six acidic residues are conserved. Asp74, Asp200, Asp318 and Glu381 are located on the putative cytoplasmic side, and Asp39 and Glu345 on the putative periplasmic side. These residues were replaced by a neutral amino acid residue or a charge-conserved one. In contrast to the transmembrane glutamic acid residues, the replacement of the two glutamic acid residues (Glu345 and Glu381) did not affect the tetracycline resistance level. Out of the other four aspartic acid residues, the only essential residue is Asp318, any replacement of which resulted in complete loss of the tetracycline resistance and transport activity. Asp318 is located in cytoplasmic loop 10-11 in the putative 14-transmembrane-segment topology of Tet(K). In the case of the tetracycline exporters of Gram-negative bacteria, the only essential acidic residue in the cytoplasmic loop region is located in loop 2-3 [Yamaguchi et al., Biochemistry 31 (1992) 8344-8348]. It may be a general role for tetracycline efflux proteins that three transmembrane and one cytoplasmic acidic residues are mandatory for the tetracycline transport function.     

Experimental frames in a modern modeling and simulation system

We investigate the experimental frame concept for discrete event simulation. We first give a brief history of experimental frames and then present and discuss the desired properties of a modern approach to experimental frames. Lastly, we describe the experimental frames implemented in the Hierarchical Modeling and Simulation System-Java (HiMASS-j). HiMASS-j is a prototype modeling and simulation system that uses the Hierarchical Control Flow Graph Model paradigm, visual interactive modeling, and the modern approach to experimental frames.     

Solution of the Zakai equation by separation of variables

An exact expression for the unnormalized conditional density is derived for certain nonlinear estimation problems. The basic method is to solve the Zakai equation using separation of variables. The new filter is a generalization of the Kalman-Bucy filter, the Benes̆ filter, and other nonlinear filters within a unified framework.