Development of a continuous respirometer

A continuous oxygen uptake meter or continuous respirometer was developed which produced a rapid and reliable response to systemic shocks. The respirometer basically is a 101. Plexiglas laboratory activated sludge unit with a variable volume air tight side car. The feed enters the completely mixed aeration basin and is pumped into the side car. The side car is the site of the oxygen uptake measurements as indicated by a continuously monitoring dissolved oxygen probe. The system was most sensitive to changes in influent concentrations when run at an F/M = 0.1. Response time for a change in DO of 0.1 ppm was less than 4 min. The continuous respirometer was tested employing both synthetic and raw industrial wastes.     

Spatial patterns of cadmium and lead deposition on and adjacent to National Park Service lands in the vicinity of Red Dog Mine, Alaska

Heavy metal escapement associated with ore trucks is known to occur along the DeLong Mountain Regional Transportation System (DMTS) haul road corridor in Cape Krusenstern National Monument, northwest Alaska. Heavy metal concentrations in Hylocomium splendens moss (n = 226) were used in geostatistical models to predict the extent and pattern of atmospheric deposition of Cd and Pb on Monument lands. A stratified grid-based sample design was used with more intensive sampling near mine-related activity areas. Spatial predictions were used to produce maps of concentration patterns, and to estimate the total area in 10 moss concentration categories. Heavy metal levels in moss were highest immediately adjacent to the DMTS haul road (Cd > 24 mg/kg dw; Pb > 900 mg/kg dw). Spatial regression analyses indicated that heavy metal deposition decreased with the log of distance from the DMTS haul road and the DMTS port site. Analysis of subsurface soil suggested that observed patterns of heavy metal deposition reflected in moss were not attributable to subsurface lithology at the sample points. Further, moss Pb concentrations throughout the northern half of the study area were high relative to concentrations previously reported from other Arctic Alaska sites. Collectively, these findings indicate the presence of mine-related heavy metal deposition throughout the northern portion of Cape Krusenstern National Monument. Geospatial analyses suggest that the Pb depositional area extends 25 km north of the haul road to the Kisimilot/Iyikrok hills, and possibly beyond. More study is needed to determine whether higher moss heavy metal concentrations in the northernmost portion of the study area reflect deposition from mining-related activities, weathering from mineralized Pb/Zn outcrops in the broader region, or a combination of the two. South of the DMTS haul road, airborne deposition appears to be constrained by the Tahinichok Mountains. Heavy metal levels continue to diminish south of the mountains, reaching a minimum in the southernmost portion of the study area near the Igichuk Hills (45 km from the haul road). The influence of the mine site was not studied.     

Improving the Quality of Cellulose for Use in Disposable Sanitary and Hygiene Products

Fibre Chemistry - Under modern conditions the creation of materials for sanitary hygiene and medical products based on cellulose is of paramount importance. Development and improvement in this area...     

Application of Mathematical Modeling in Technology for the Recovery of Rubber from Latex in a Magnetic Field

Theoretical Foundations of Chemical Engineering - The paper presents a study of the process of the isolation of styrene-butadiene rubber from latex with the method of mathematical planning for a...     

Multilayer Glass Quality Improvement during Production

Glass and Ceramics - Selective quality control of manufactured multilayer windshields was conducted. Deviations of curved products from a specified shape were brought to light. Linear regression...     

Development of a Catalyst Based on Titanium Nanoparticles in a Zeolite Matrix

Glass and Ceramics - A catalyst was developed in the form of a composite based on a zeolite matrix modified with titanium nanoparticles based on zeolite raw materials from the Kulikovskoe deposit...     

Optimization of Technological Regulation of Container Glass Production: Best Available Technologies,General Binding Rules,and Carbon Intensity of Products

Glass and Ceramics - A system for technological regulation of adverse environmental impacts (AEI) that is based on the best available technologies (BAT) was analyzed. The expediency of updating the...     

Composition and Tribological Properties of Hardened Cutting Blades of Tillage Machines under Abrasive Deterioration

The article presents the results of metallographic study of low-carbon 20 steel grade and high-carbon 70 and 65G steel grades upon carburizing, heat treatment, and laser hardening. The change in the microhardness through the depth of the surface layer of steels and their abrasion resistance upon hardening under different conditions has been measured. Optimal hardening conditions have been proposed for steels for cutting blades of tillage machines that enable the durability of the blades to be improved.     

Control of the Machining Precision in Thread Cutting

Russian Engineering Research - In research on thread cutting, the flaws inevitably arising in the first two and last two turns of the thread, when the process is unsteady, are analyzed....