Alkaline-Earth Tungstates: Equilibrium and Stability in the M-W-O Systems

Phase relations in the systems alkaline earth oxide-tungsten trioxide and their stability with metallic tungsten were investigated by the quenching technique using sealed capsules. In the system BeO-WO₂, no intermediate compounds were formed. Binary mixtures resulted in a eutectic at 1185°C and 37 mole % BeO. In the system MgO-WO₃, the 1:1 compound was stable and melted congruently at 1358°C. There are two crystalline modifications of this compound. The well-known wolframite-type form is stable below 1165°C. Two eutectics were found: 1120°C and 28.5 mole % MgO and 1318°C and 55.0 mole % MgO. In the systems CaO-WO₃, SrO-WO₃, and BaO-WO₃, two binary compounds are stable. The 1:1 compounds with the scheelite-type structure melt, respectively, at 1580°, 1535°, and 1475°C, and form eutectics with WO₃ at 1135°, 1073°, and 935°C, all with a eutectic composition near 75 mole % WO₃. The 3:1 compounds having the distorted (NH,)₃FeF₆-type structure melt at ∼2250°, 2225°, and 1795°C. The eutectics between these two compounds are at 1490°C and 56.5 mole % CaO, 1410°C and 57.0 mole % SrO, and 1320°C and 58.2 mole % BaO. Phase transformations to an ideal (NH₄)₃FeF₆-type structure in Sr₃WO₆ and Ba₃WO₆, were observed at 1100° and 805° C, respectively, by application of both high-temperature X-ray diffraction and DTA. At 1700°C, metallic tungsten exists in equilibrium with liquid, the alkaline earth oxides, W₁₈O₄₉, the 3:1 ternary oxides, and with combinations thereof.     

CIVIC CAPACITY AND SCHOOL/COMMUNITY PARTNERSHIPS IN A FRAGMENTED SUBURBAN SETTING: THE CASE OF 24:1

ABSTRACT: This paper uses the “civic capacity” framework to analyze an emerging school–community reform initiative, called 24:1, focused on an inner‐ring suburban school district. Contrary to the existing literature on civic capacity, we argue that institutions strongly influence civic capacity building. A fragmented public sector and weak institutions of civil society, especially when combined with racial divisions and poverty, restrict the ability of local actors to collaborate among themselves and partner with outside institutions. Despite these daunting challenges, 24:1, led by a local nonprofit with a long history in the area and a school district with dynamic new leadership, has mobilized a diverse coalition of stakeholders and built consensus around a comprehensive plan for revitalization. But stronger indigenous institutions, as well as greater support from the business community, will be needed to sustain the initiative.     

CONTEXT CUES AS MEDIATORS: I. THREE-STAGE PARADIGMS.

TESTED THE EFFECT OF COLOR AS A MEDIATOR IN PAIRED-ASSOCIATE LEARNING IN 4 EXPERIMENTS WITH 120 STUDENTS UTILIZING STIMULUS EQUIVALENCE, RESPONSE EQUIVALENCE, AND CHAINING PARADIGMS. A COLOR WAS PRESENTED ADJACENT TO 2 DIFFERENT ITEMS IN THE LEARNING OF LIST 1. BY EXPERIMENTAL GROUPS. ITEMS COUPLED WITH THE SAME COLOR WERE PAIRED IN LIST 2. THE DIFFERENCE IN LEARNING SCORES ON LIST 2 BETWEEN THE MEDIATION PAIRS AND NEW OR CONTROL PAIRS GENERALLY INDICATED THAT MEDIATION EFFECTS OCCURRED IN THE EXPERIMENTAL GROUPS AS COMPARED TO 2 CONTROL GROUPS. (FRENCH SUMMARY) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of irradiation and modified atmosphere packaging on the microbiological and sensory quality of pork stored at refrigeration temperatures

The effect of combining low-dose irradiation (1.75 kGy) with modified atmosphere packaging (MAP) on the microbiological and sensory quality of pork chops stored at refrigeration temperatures was studied. The microflora of irradiated MAP pork was almost exclusively composed of lactic acid bacteria, predominantly Lactobacillus spp. Modified atmospheres containing either 25 or 50% CO₂, balance N₂, resulted in the best microbial control in irradiated pork held at 4°C, compared to an unirradiated MAP control, and these atmospheres were subsequently used in sensory studies. The atmosphere containing 25% CO₂ 75% N₂ maintained the uncooked colour and odour of irradiated pork chops more effectively than 50% CO₂ 50% N₂. Therefore packaging in a modified atmosphere containing 25% CO₂, balance N₂, followed by irradiation to a dose of 1.75 kGy is recommended to improve the microbiological and sensory quality of pork chops.     

Environmental Health and the Water Distribution System: A Case History of an Outbreak of Giardiasis

I n J uly /A ugust 1985 a significant outbreak of giardiasis occurred in part of south Bristol. An epidemiological inquiry carried out strongly suggested that the outbreak was water-borne. Although no positive evidence was found to link the outbreak with mains water. the Company immediately accepted its feasibility m d co-operated fully with the Hcalth Authorities in the ensuing investigation.
The piper ilescrihes the investigation to ascertain whether the supply system was involved, and considers some of the broader implications of the situation.     

Visual Metrics for the Maxton Plains Alvars in Michigan,USA

Planners, designers, environmentalists, concerned citizens, and government officials are interested in the management and preservation of small rare and unique ecological environments. Scholars have discovered that land-use and visual quality metrics often co-vary together and that various land-uses reside on a continuum scale from high respondent preference (biospheric land-uses) to low respondent preference (noospheric land-uses). This study assessed and documented the visual metrics for the Maxton Plains alvar/alvar grassland plant communities found on Drummond Island, Michigan, USA. These unique, small, and rare landscape types are not usually studied by large-scale visual quality mapping efforts which assess urban areas, woodlands, water, farmland, pastureland, and prairies. The visual metrics were assessed using two versions of predictive visual quality assessment models. Results from 60 field photographs reveal that the visual metrics assessment for the Maxton Plains alvars/alvar grasslands have a moderate visual preference, consistent visual quality scores: ranging from the low to middle 50s with the first equation and high 40s to low 50s with the second equation. Compared to many landscape and land-uses, these environments have scores that indicate a moderate visual preference and appreciation. Scores beyond±2.5 of the mean would indicate a significant (p≤0.05) perceivable drift from the existing conditions. The visual metrics provide a numerical framework for managing the spatial contents within and adjacent to the alvars. Landscape features such as buildings, invasive woodlands, agriculture, and pavement would all decrease the visual quality beyond the ± 2.5 score range.