RISQ-reduced instruction set quantum computers

Abstract

Candidates for quantum computing which offer only restricted control, e.g. due to lack of access to individual qubits, are not useful for general purpose quantum computing. We present concrete proposals for the use of systems with such limitations as RISQ-reduced instruction set quantum computers and devices-for simulation of quantum dynamics, for multi-particle entanglement and squeezing of collective spin variables. These tasks are useful in their own right, and they also provide experimental probes for the functioning of quantum gates in premature prototypes of quantum computers.     

Einfluß der Extraktstoffe von Fichten- und Kiefernspänen auf die Formaldehyd-Abgabe

Subject The formaldehyde release of unextracted and extracted spruce (Picea abies Karst.) and pine chips (Pinus sylvestris L.) was determined at different temperatures using the flask method (EN 717.3). The results reveal that extracted chips release significantly lower amounts of formaldehyde compared to unextracted chips. Moreover, pine chips emit more formaldehyde than spruce chips.      

Cable crossings-derating considerations. II. Example of derivationof derating curves

For pt.I see ibid., vol.14, no.3, p.705-14 (1999). Cables crossing other heat sources either perpendicularly or at oblique angles will experience a rise in conductor temperature which should result in ampacity derating. In the first part of the paper a mathematical model for calculation of derating factors was presented. In this paper, a practical numerical example is considered with a 138 kV pipe-type cable crossing a 10 kV distribution circuit. The numerical analysis presented confirms experimental findings reported in the literature that the cable crossing may elevate conductor temperature by as much as 20°C     

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Framework for developing image-based dirt particle classifiers for dry pulp sheets

One important aspect of assessing the quality in pulp and papermaking is dirt particle counting and classification. Knowing the number and types of dirt particles present in pulp is useful for detecting problems in the production process as early as possible and for fixing them. Since manual quality control is a time-consuming and laborious task, the problem calls for an automated solution using machine vision techniques. However, the ground truth required to train an automated system is difficult to ascertain, since all of the dirt particles should be manually segmented and classified based on image information. This paper proposes a framework for developing and tuning dirt particle detection and classification systems. To avoid manual annotation, dry pulp sheets with a single dirt type in each were exploited to generate semisynthetic images with the ground truth information. To classify the dirt particles, a set of features were computed for each image segment. Sequential feature selection was employed to determine a close-to-optimal set of features to be used in classification. The framework was tested both with semisynthetically generated images based on real pulp sheets and with independent original real pulp sheets without any generation. The results of the experiments show that the semisynthetic procedure does not significantly change the properties of images and has little effect on the particle segmentation. The feature selection proved to be important when the number of dirt classes changes since it allows to improve the classification results. Using the standard classification methods, it is possible to obtain satisfactory results, although the methods modeling the data, such as the Bayesian classifier using the Gaussian Mixture Model, show better performance.     

Very High Volume Aerosol Sampling with a Novel Drum Centrifuge

For chemical analysis of trace compounds, comparatively large amounts of dust have to be collected. If good time resolution is required, very high sampling flow rates are mandatory. The operating principle of the drum centrifuge built to cope with these requirements is based on particle deposition on the inner surface of a porous rotating drum. Due to the rotation, a pressure gradient draws the aerosol into the bore of the axis and from there radially outward through a number of holes into the drum. The aerosol then moves to the periphery of the double-walled drum, which consists of two 0.15-mm-thick metal sheets with 1-mm spacing. Each of these metal sheets is perforated by several rows of small slits resulting in porosity of 16%. The slits in the inner and outer sheet are displaced, so that the particles will be strongly deflected on their way out of the rotating drum. Under the combined action of centrifugal forces and strong streamline deflection in the displaced slits of the two thin-walled drums, the particles are deposited. Flow rate as a function of rpm and collection efficiency as a function of particle size were determined experimentally. For simplicity, only the flow field of two (nonrotating) displaced slits was mathematically analyzed. The resulting 2-D solution of the Navier-Stokes equation was used for deterministic limiting trajectory calculations in the case of large particles. Diffusional motion of small particles was allowed for by Monte Carlo trajectory calculation. The calculated deposition efficiencies agree satisfactorily with the experimental results. At 3000 rpm a flow rate of 1200 m³/hr and efficiencies of 91% for 2.1-μm particles, 75% for 0.6-μm particles, and 48% for 0.04-μm particles were obtained. For easy extraction of the collected particulate matter, the device is equipped with an ultrasonic cleaning bath.     

STEAM DRYING OF WOOD CHIPS IN PNEUMATIC CONVEYING DRYERS

ABSTRACT

A model for a pneumatic conveying dryer is presented. Although the main emphasis is put on superheated steam drying of wood chips, it can be used for other porous materials as well

The model includes a comprehensive two-dimensional model for the drying of single wood chips which accounts for the main physical mechanisms occurring in wood during drying. The external drying conditions in a pneumatic conveying dryer were calculated by applying the mass, heat and momentum equations for each incremental step in dryer length. A plug flow assumption was made for the dryer model and the single particle and dryer models were solved in an iterative manner. The non-spherical nature of wood chips were accounted for by measuring the drag and heat transfer coefficients

Model calculations illustrate the complex interactions between steam, particles and walls which occur in a flash dryer. The drying rate varies in a very complex manner through the dryer. The internal resistance to mass transfer becomes very important in The drying of less permeable wood species such as spruce. Two effects were observed as the particle size was increased: firstly the heat transfer rate decreased, and secondly the residence time increased. To some extent, these effects compensate for each other, however, the net result is that larger chips have a higher final moisture content.     

Delignification and Bleaching Response of Earlywood and Latewood

Abstract

The delignification response in cooking and the impact of bleaching on earlywood and latewood were studied. Spruce earlywood and latewood chips were pulped by the kraft process and subsequently treated with one bleaching chemical at a time. In cooking, latewood required a higher alkali charge to reach the same kappa number. No difference in the light absorption coefficient between the different fiber types was observed. After oxygen delignification the earlywood fibers had a higher light absorption coefficient at the same kappa number. The difference in light absorbing material was maintained when bleaching was performed with chlorine dioxide, ozone, and peracetic acid. Hydrogen peroxide decreased the light absorbing structures in the earlywood to the same level as for latewood. The earlywood pulp had a higher brightness at a given kappa number than the latewood. The higher brightness remained through all bleaching operations and was primarily due to a higher light scattering ability.