NETWORK LAYER DESIGN ISSUES IN A HOME AUTOMATION SYSTEM

The CEBus (Consumer Electronic Bus) has been proposed by the Electronics Industries Association (EIA) as a standard for home automation systems. In this paper, we present the design and implementation of a network layer that adheres to the standards and at the same time versatile and expandable. The basic primitives and characteristics of the network layer as well as its interface with the other layers are presented, followed by a presentation of the software and hardware components of the design.     

Sodium Tripolyphosphate and Sodium Ascorbate Monophosphate as Inhibitors of Off-flavor Development in Cooked, Vacuum-packaged, Frozen Turkey

Sodium tripolyphosphate (STP) or sodium ascorbate monophosphate (SAsMP) in water solutions (0.3 and 0.5% levels) or water only were added to ground turkey which was cooked, vacuum packaged, and stored frozen. Soapy flavor was higher, but rancid flavor and hexanal and bathophenathroline-chelateable (nonheme) iron contents were lower in samples with phosphate salts. Samples without phosphates contained the greatest amount of bathophenathroline-chelateable iron; samples with 0.5% STP contained the least. The addition of phosphate salts decreased cooking losses and increased moisture but did not affect the fat content. Generally, intensity scores for stale and rancid aroma and flavor attributes were low, < 1 for all samples.     

Linear Model for Predicting Transient Temperature during Sterilization of a Food Product

The thermal behavior of a conductive canned food during retorting was represented using an input-output linear system, with a finite order N, and a time-delay. The input of the system was the retort temperature, the output was the temperature at the thermal center of the can. This model was applied for a typical sterilization process composed of two isothermal steps. The can internal temperature was expressed as a sum of N exponential terms in which appeared the constant holding retort temperatures, the come-up and come-down times and N pairs of heat penetration parameters identified in a preliminary experiment. The model was tested on a potato mash packed in metal cans processed in a vertical still retort. Temperatures estimated by the model agreed closely with those measured during thermal processing.     

Cloning and Characterization of the KlDIM1 Gene from Kluyveromyces lactis Encoding the m26A Dimethylase of the 18S rRNA

The KlDIM1 gene encoding the m₂⁶A rRNA dimethylase was cloned from a Kluyveromyces lactis genomic library using a PCR amplicon from the Saccharomyces cerevisiae ScDIM1 gene as probe. The KlDIM1 gene encodes a 320-amino acid protein which shows 81% identity to ScDim1p from S. cerevisiae and 25% identity to ksgAp from Escherichia coli. Complementation of the kasugamycin-resistant ksgA-mutant of E. coli lacking dimethylase activity demonstrates that KlDim1p is the functional homologue of the bacterial enzyme. Multiple alignment of dimethylases from prokaryotes and yeasts shows that the two yeast enzymes display distinctive structural motives including a putative nuclear localization signal. © 1997 John Wiley & Sons, Ltd.     

Chitosan Gel Beads as a New Biosorbent for Molybdate Removal

Abstract

Metal ion sorption on chitosan is controlled by intraparticle mass transfer. This paper examines the suggestions of producing gel beads to enhance these diffusion properties. This technique consisted of two stages: firstly dissolving chitosan in acetic acid solution followed by dropping the resulting viscous solution through a thin nozzle into a casting alkaline solution (NaOH). This sorbent was tested for molybdate removal. The optimum pH range corresponded to an acid medium. A cross-linking stage in glutaraldehyde solution increases resistance to acid preventing gel beads dissolving. Metal ion concentration, particle size, chitosan conditioning and competitor ions were studied in terms of equilibrium and kinetic performances. The intraparticuiar diffusion coefficients were evaluated and sorption capacities as high as 750 mg (dry)g^?1 were obtained. Dynamic removal of molybdate in a fixed-bed reactor was also studied in terms of flow rate and column size effects.     

Detection of hepatitis A virus in oysters

A digoxigenin-labelled RNA probe with a sensitivity of 800 50% tissue culture infectious dose (TCID₅₀) was used to detect Hepatitis A Virus (HAV) in oysters. We studied the influence of extraction methodology on riboprobe detection. Oyster samples obtained by four methods of extraction and extraction-concentration were spiked with HAV (CF53 strain). There was no correlation between protein concentration and turbidity of samples, and anti-digoxigenin antibodies showed a non specific reaction. Background noise was independent of protein concentration and disappeared when HAV RNA isolation by phenol/chloroform extraction was introduced, but HAV RNA could not be detected by this technique. In the presence of Acid Guanidinium Thiocyanate (AGT), RNA from HAV suspension was detected following phenolic extraction with a detection threshold of 8.10⁴ TCID₅₀ of spotted virus. HAV detection in oyster extract by a digoxigenin-labelled riboprobe appeared useful in shellfish virology, at least for a primary screening of samples.     

THE “UCKRON-1” TEST PROBLEM FOR REACTION ENGINEERING MODELING†

Testing kinetic models against a “true” and detailed kinetic expression was the aim of the Workshop on Kinetic Model Development at the Denver AIChE Meeting in August, 1983. For this purpose an artificial reaction mechanism was created, based on the known thermodynamics of the methanol synthesis as a framework. The kinetic rate laws, that were derived from this mechanism, were made thermodynamically consistent by achieving agreement between equilibrium constants calculated at various temperatures from the given, real original thermodynamic relationship and those calculated from the detailed reversible kinetic expressions.

Using the artificial kinetics as the "true" one, CSTR experiments were simulated. The results of a statistically designed set of experiments were published after 5% random error was added to the data. Participation was invited for all interested to correlate the data, develop kinetic models and to calculate the performance of the specified reactor.

The results of 19 submitted entries are summarized with the conclusion that the models had more differences than were expected, but their predictive values were not as different as was anticipated, if the extreme high production rates due to thermal runaways are not considered. This in turn points out the necessity to check models experimentally, in pilot plant, not only for predicted optimum, but also for calculated runaway conditions. Models which did not capture the true character of this reaction failed to predict the onset of runaway reactions.     

Physicochemical characterisation of calcium phosphates prepared from milk ultrafiltrates: Effect of the mineral composition

This study deals with the precipitation of calcium phosphate in permeates removed from milks at different pH (6.7, 5.2 and 4.6). An overall high yield of precipitation of calcium and phosphate (70–80%, respectively) was obtained for all precipitates with Ca/P molar ratios close to 1.5. The suspended milk‐derived calcium phosphate (MDCP) precipitates had 8–14 μm size and ?14 to ?28 mV zeta potential. The dried MDCP precipitates were identified as amorphous calcium phosphate (ACP), stable over 18 months of storage at room temperature.     

DO TRANSIT‐DEPENDENT NEIGHBORHOODS RECEIVE INFERIOR BUS ACCESS? A NEIGHBORHOOD ANALYSIS IN FOUR U.S. CITIES

ABSTRACT: Intrajurisdictional delivery of publicly provided services often results in observable service level differences that vary by spatial subunit (neighborhood). These variations are related to the sociodemographic characteristics of neighborhoods and have been hypothesized in prior literature to be the result of bias against or favoritism toward certain neighborhoods. Using path regression, this paper examines publicly provided bus service in four cities—Asheville, North Carolina; Charlotte, North Carolina; Mobile, Alabama; and Richmond, Virginia—to examine whether the socioeconomic character of a neighborhood is related to the share of municipal bus service it receives. With this analysis, we test an expanded version of Lineberry's underclass hypothesis. Specifically, do transit‐dependent neighborhoods, or those with a high percentage of non‐Caucasian, low‐income, elderly, or student residents receive inferior bus service? Findings confirm prior research that both standard rules and bias are present in service delivery decisions.