MODELING THE TEMPERATURE EFFECT ON THE FLOW BEHAVIOR OF SWEET POTATO PUREE1

A study was conducted to investigate the effect of temperature on viscosity of sweet potato (SP) puree. Rheological data of the puree were measured using a Bohlin VOR Rheometer. Shear rates employed ranged from 0.01–921 s^?1. Thermal scans were run at 15, 25, 40, 60, 75, and 90C. The puree exhibited “shear thinning” behavior with a yield stress value of 10 Pa at each temperature tested. The characteristic of the flow behavior of the puree was determined by fitting the experimental data to Herschel-Bulkley, Casson and Modified Casson models. The model with the best fit was then used to represent the combined effect of shear rate and temperature on the apparent viscosity of SP puree in a model based upon the Modified Casson model. The model was validated using data for SP puree samples at 50C. Results showed that, within the experimental conditions used in this study, the model could adequately predict apparent viscosities of sweet potato puree processed at different temperatures.     

Unstable rational function approximation

The problem is considered of approximating a transfer function with stable and unstable poles by a lower-order transfer function with the same number of unstable poles. A method is suggested and compared with alternative known methods based on Hankel-norm approximation. Examples suggest that no one method always outperforms other methods in terms of minimizing the approximation error.     

CYBERSECURITY AT THE LOCAL GOVERNMENT LEVEL: BALANCING DEMANDS FOR TRANSPARENCY AND PRIVACY RIGHTS

Cybersecurity demands are forcing public officials across the globe to focus on two core values that often conflict—transparency (the public good) and privacy (citizen and private sector confidentiality). An e‐survey of Florida county government officials measures how cross‐pressured they are, identifies the types of information about individuals and government employees that are the most difficult to protect, examines the interest groups (public, private, and nonprofit) that act as watchdogs, and delineates the actions administrators see as critical to promoting balance. The results show intense cross‐pressures and greater difficulty in protecting citizens’ bioinformation, medical records, and financial data than in securing employee information. Information technology professionals and their associations are the most active in tracking privacy protection. The media and citizen activists monitor transparency the closest. More funding, personnel, equipment, and training, better software, more rigorous enforcement, and clearer standards and procedures are needed to balance privacy protection and transparency in cybersecurity policy making.     

The effects of spatial resolution on the classification of Thematic Mapper data

Actual and degraded LANDSAT-4 Thematic Mapper (TM) data were analysed to examine the effect of spatial resolution on the performance of a per pixel, maximum-likelihood classification algorithm. Analysis of variance (ANOVA) and a balanced, three-factor, eight-treatment, fixed-effects model were used to investigate the interactions between spatial resolution and two other TM refinements, spectral band configuration and data quantization. The goal was to evaluate quantitatively the effects of these attributes on classification accuracies obtained with all pixels (pure pixels plus mixed pixels) and on accuracies obtained with pure pixels alone.

A comparison of results from these separate analyses supported previous explanations of the effects of increasing spatial resolution. First, the difficulty in classifying mixed pixels was demonstrated by an average 21 per cent decrease in percentage accuracy from the pure-pixel case to the pure-plus-mixed-pixel case for the eight ANOVA treatments. In the pure-pixel case, an increase in spatial resolution from 80 to 30 m caused an average 6·1 per cent decrease in percentage accuracy when the other factors were held constant. This decrease was attributed to increased within-class spectral variability at the TM resolution. Finally, in the pure-plus-mixed-pixel case, increasing the spatial resolution did not significantly affect accuracy. This insignificance was attributed to a reduced proportion of mixed pixels at the TM resolution which counteracted the detrimental effects of increased spectral variability. These results point to a need for the development of new approaches to classification which take full advantage of the TM spatial resolution.     

From Youla–Kucera to Identification, Adaptive and Nonlinear Control

Some 20 years ago, formulae were presented for the set of all linear time-invariant controllers stabilizing a linear time-invariant plant. This paper traces the development of many ideas from these formulae, covering linear and control, identification, adaptive control and nonlinear systems.     

NATIONAL SECURITY/EMERGENCY PREPAREDNESS AND DISASTER RECOVERY COMMUNICATIONS VIA ACTS

During the period from early 1993 to 1994, the U.S. National Communication System (NCS), a government agency, sponsored the development and execution of several fixed and mobile experiments using the advanced communications technology satellite (ACTS). The purpose of these experiments was to evaluate the feasibility of integrating an ACTS-like communications system into national security/emergency preparedness (NS/EP) operational scenarios. These experiments focused on clear and secure voice communications in both the fixed and mobile environment. For the mobile experiments, the focus was on the performance of both clear and secure voice in the land-mobile satellite communications channel. For the fixed experiments, the focus was on the use of a T1 terminal for restoration of communication services in the event of a disaster and for remote user communications. The results of these experiments are described in this paper.     

FUNDRAISING COALITIONS IN OPEN SEAT MAYORAL ELECTIONS

ABSTRACT: Mayoral candidates need to assemble a fundraising coalition so they can raise sufficient funds to be competitive. What is the nature of those coalitions? Are they narrow partnerships of like‐minded interests, or are they broad alliances encompassing many different groups? Also, are the coalitions assembled by opposing candidates fundamentally different, or do most candidates receive their funds from the same sources? This article explores these questions through an analysis of five open seat mayoral elections in New York, Los Angeles, San Francisco, and Seattle. Most candidates assemble broad coalitions of many different groups, and because of this breadth candidates often have internally inconsistent coalitions (especially labor‐backed candidates). Further, the fundraising coalitions of opposing candidates are usually quite similar. The results show that mayoral elections are not characterized by competing coalitions of donors and that voters who desire to use financial backing as a factor influencing their decision have limited choices.     

Investigation of Fluid Flow and Steel Cleanliness in the Continuous Casting Strand

Fluid flow in the mold region of the continuous slab caster at Panzhihua Steel is investigated with 0.6-scale water model experiments, industrial measurements, and numerical simulations. In the water model, multiphase fluid flow in the submerged entry nozzle (SEN) and the mold with gas injection is investigated. Top surface level fluctuations, pressure at the jet impingement point, and the flow pattern in the mold are measured with changing submergence depth, SEN geometry, mold width, water flow rate, and argon gas flow rate. In the industrial investigation, the top surface shape and slag thickness are measured, and steel cleanliness including inclusions and the total oxygen (TO) content are quantified and analyzed, comparing the old and new nozzle designs. Three kinds of fluid flow pattern are observed in the SEN: “bubbly flow,” “annular flow,” and an intermediate critical flow structure. The annular flow structure induces detrimental asymmetrical flow and worse level fluctuations in the mold. The SEN flow structure depends on the liquid flow rate, the gas flow rate, and the liquid height in the tundish. The gas flow rate should be decreased at low casting speed in order to maintain stable bubbly flow, which produces desirable symmetrical flow. Two main flow patterns are observed in the mold: single roll and double roll. The single-roll flow pattern is generated by large gas injection, small SEN submergence depth, and low casting speed. To maintain a stable double-roll flow pattern, which is often optimal, the argon should be kept safely below a critical level. The chosen optimal nozzle had 45-mm inner bore diameter, downward 15 deg port angle, 2.27 port-to-bore area ratio, and a recessed bottom. The pointed-bottom SEN generates smaller level fluctuations at the meniscus, larger impingement pressure, deeper impingement, and more inclusion entrapment in the strand than the recess-bottom SEN. Mass balances of inclusions in the steel slag from slag and slab measurements show that around 20 pct of the alumina inclusions are removed from the steel into the mold slag. However, entrainment of the mold slag itself is a critical problem. Inclusions in the steel slabs increase twofold during ladle changes and tenfold during the start and end of a sequence. All of the findings in the current study are important for controlling slag entrainment.     

The influence of radiation on the skin and the basis of protection

This paper reviews current ideas concerning the reactions involved in sunburn, suntanning, premature ageing and carcinogenesis due to acute or chronic exposure to sunlight. The physiological mechanisms of protection involving melanin pigmentation, thickening of the epidermal horny layer and urocanic acid are briefly discussed. The importance of wavelengths from 290-315 nm (UV-B) for these reactions is emphasized as is the need to investigate further the involvement of longer wavelength (UV-A, 315-400 nm).
L'influence des radiations sur la peau et les principes de la protection solaire
Cet article passe en revue les données actuelles concernant les réactions impliquées dans les processus de brûlure, bronzage, vieillissement prématuré et carcinogenese dus aux expositions aigues ou chroniques de la peau à la lumière solaire. Les mécanismes physiologiques de protection qui mettent en oeuvre la pigmentation par la mélanine, l'épais-sissement de la couche cornée, et l'acide urocanique sont brièvement discutés. On insiste sur l'importance des UV-B (longueurs d'onde de 290 à 315 nm) dans ces réactions, de même que sur la nécessité d'entreprendre des études plus approfondies sur le rôle des UV-A (315-400 nm).