Flow dynamics or ‘quaking’ in gravity discharge from silos

This paper reviews the characteristics of pulsating or cyclic flow of bulk solids during gravity discharge in bins and silos. The dynamic load phenomenon is often referred to as “silo quaking” and is influenced by various factors related to the type of flow pattern developed in the bin and the flow properties of the bulk material. Of particular relevance is the influence of ‘slip-stick’ during shear flow, and the velocity at critical sections in the silo during discharge. An overview of recent and current research on this subject is presented.     

Applications of ultrashort pulse propagation in Bragg gratings forwavelength-division multiplexing and code-division multiple access

We discuss theoretical and experimental studies on the propagation of ultrashort pulses through fiber Bragg gratings. We also consider several applications in optical communications to be found by combining ultrashort pulses and fiber Bragg gratings: a multiwavelength source for wavelength-division-multiplexed systems and a means for implementing optical code-division multiple access     

Optical characterization of low-temperature-grown GaAs forultrafast all-optical switching devices

Low-temperature-grown GaAs (LT-GaAs) is a promising material for all-optical switching devices due to its outstanding optical characteristics. In this paper, we outline a simplified model we have developed to describe the dynamics of the carriers in this material. We also report the results of a series of measurements that we have performed to characterize the optical properties of the material. Specifically, we present the first measurements of the two-photon absorption coefficient and the refractive index changes as a function of the growth and annealing temperatures in LT-GaAs. Finally, we show how our model can be used to optimize the material for applications in all-optical switching     

Monitoring Proteolysis During Cheddar Cheese Ripening Using Two-Dimensional Gel Electrophoresis

A 2-D gel electrophoretic method, consisting of isoelectric focusing and alkaline urea-PAGE was used to monitor proteolysis during ripening (180d, 5°C and 8°C) of full- and reduced-fat Cheddar cheese. The method enabled quantifying changes in levels of peptides in cheese with good spot-resolution. Results can complement those from other analyses, especially those for determining low MW peptides. Notable effects were found for cheese composition and ripening temperature on gel pattern and on relative levels of selected proteolysis products. In both cheese varieties, most peptides reached a maximum during the first 3 ripening months and gradually disappeared as ripening advanced.     

Two distinct DNA ligase activities in mitotic extracts of the yeast Saccharomyces cerevisiae

Four biochemically distinct DNA ligases have been identified in mammalian cells. One of these enzymes, DNA ligase I, is functionally homologous to the DNA ligase encoded by the Saccharomyces cerevisiae CDC9 gene. Cdc9 DNA ligase has been assumed to be the only species of DNA ligase in this organism. In the present study we have identified a second DNA ligase activity in mitotic extracts of S. cerevisiae with chromatographic properties different from Cdc9 DNA ligase, which is the major DNA joining activity. This minor DNA joining activity, which contributes 5-10% of the total cellular DNA joining activity, forms a 90 kDa enzyme-adenylate intermediate which, unlike the Cdc9 enzyme-adenylate intermediate, reacts with an oligo (pdT)/poly (rA) substrate. The levels of the minor DNA joining activity are not altered by mutation or by overexpression of the CDC9 gene. Furthermore, the 90 kDa polypeptide is not recognized by a Cdc9 antiserum. Since this minor species does not appear to be a modified form of Cdc9 DNA ligase, it has been designated as S. cerevisiae DNA ligase II. Based on the similarities in polynucleotide substrate specificity, this enzyme may be the functional homolog of mammalian DNA ligase III or IV.     

Reading handwritten digits: a ZIP code recognition system

A neural network algorithm-based system that reads handwritten ZIP codes appearing on real US mail is described. The system uses a recognition-based segmenter, that is a hybrid of connected-components analysis (CCA), vertical cuts, and a neural network recognizer. Connected components that are single digits are handled by CCA. CCs that are combined or dissected digits are handled by the vertical-cut segmenter. The four main stages of processing are preprocessing, in which noise is removed and the digits are deslanted, CCA segmentation and recognition, vertical-cut-point estimation and segmentation, and directly lookup. The system was trained and tested on approximately 10000 images, five- and nine-digit ZIP code fields taken from real mail     

Physical training: a tool for increasing work tolerance limits of employees engaged in manual handling tasks.

The lack of physical fitness is a contributing factor to the etiology of musculoskeletal disorders resulting from the manual handling of material in industry. Thus the major objectives of this paper were (1) to discuss the role of physical fitness in the control of occupational injuries; (2) to review techniques available in the exercise physiology literature for increasing human physical capacity in industry; and (3) to review and evaluate studies on the effects of physical training on individuals engaged in manual handling tasks.     

A study of impact toughness of Fe-Cr-X damping alloys

A study was carried out on the impact toughness of Fe- Cr- Х damping alloys. Two measures proved to be effective in improving impact toughness. One was to lower carbon plus nitrogen content to an ultra- low level. This method is suitable for single- phase ferrite alloy. The other is to use dual- phase damping alloys. The presence of martensite in Fe- Cr- Х alloys can enhance impact toughness remarkably, but lower damping capacity drastically. This shows the importance of achieving balance between mechanical prop-erties and damping capacity by properly controlling martensite volume fraction in dual- phase alloys.     

USE OF DIELECTRIC SPECTROSCOPY TO ASSESS ADHESIVELY BONDED COMPOSITE STRUCTURES, PART I: WATER PERMEATION IN EPOXY ADHESIVE

This three-part series of papers describes studies on water penetration into epoxy resins and the use of low- and high-frequency dielectric spectroscopy as a method of monitoring the health of adhesive bond lines in bonded epoxy/graphite composite structures. The first paper is concerned with an investigation of the effect of water ingress into the epoxy adhesive resin used in the manufacturing of the adhesive bond. This study reports a dynamic mechanical thermal analysis (DMTA) and gravimetric analysis of the effects of water uptake and interprets the data in terms of various processes that can occur within the adhesive. Surprisingly high values of water absorption were observed in samples where the edges were unconstrained and presented direct access to the fibre matrix for the moisture. The study demonstrated the effects of postcure and leaching on the sorption and desorption processes and provided background data, which are necessary for the interpretation of the study described in Parts II and III of this series of articles.