A forced-air self-cleaning system for a Wiley-type mill

1999 ◽  
Vol 79 (3) ◽  
pp. 365-367
Author(s):  
R. Drapeau
Keyword(s):  
Air Quality ◽  
Key Words ◽  
Health Risks ◽  
Facial Mask ◽  
Cleaning System ◽  
Self Cleaning ◽  
Forced Air ◽  
Time Required

A forced-air self-cleaning system was designed and installed on a Wiley-type laboratory mill. This system reduces the time required to grind a forage sample by 30%. In addition, this forced-air self-cleaning system allows the operator to remove the facial mask by reducing dust and improving air quality and diminishing health risks. Key words: Mill, self-cleaning system

Prediction of available potassium in Ontario soils by electro-ultrafiltration and chemical extraction

1992 ◽  
Vol 72 (2) ◽  
pp. 159-167 ◽  
Author(s):  
Liangxue Liu ◽  
T. E. Bates ◽  
T. S. Tran
Keyword(s):  
Organic Matter ◽  
Soil Properties ◽  
Key Words ◽  
Soil Ph ◽  
Chemical Extraction ◽  
K Uptake ◽  
Chemical Methods ◽  
Exchangeable Calcium ◽  
Time Required

The extractions of soil K by electroultrafiltration (EUF) and by chemical methods were compared as predictors of plant-available K for greenhouse-grown alfalfa on 38 Ontario soils. The relation of soil properties to the amount of K extracted by EUF fractions was also examined. The contents of silt and clay were negatively correlated with EUF-K at 50 V and 22 °C and positively correlated with EUF-K at 400 V and 80 °C. Soil pH and organic matter were not significantly correlated with the amounts of K extracted in the EUF-K fractions. The EUF extraction of K was influenced by the presence of carbonate or high exchangeable calcium in soils. Similar correlations were obtained between K uptake and K extracted by chemical methods and the sum of EUF-K fractions. When used along with other soil properties, EUF-K fractions and K extracted by chemical methods predicted availability of soil K with roughly equal ability. The model using the sum of K extracted by EUF at 50, 200 and 400 V is the simplest one and contains three variables, K, K2 and Ca2. The use of EUF is limited due to cost of equipment and time required for analysis, unless a number of nutrients can be accurately determined on one extract. Among the chemical methods, equations developed using three nonacidic extradants, NaCl, ABDTPA and NH4OAc explained more variation in K uptake than two acidic extractants, Mehlich 3 and 0.1 M HNO3. The NaCl model, ABDTPA model and NH4OAc model contained the same variables and had similar R2 values (0.88–0.91). Key words: Available K, chemical methods, electro-ultrafiltration, EUF-K fractions, K uptake

Swimming Stamina Differences Between Genotypically Distinct Forms of Rainbow (Salmo gairdneri) and Steelhead Trout

1977 ◽  
Vol 34 (7) ◽  
pp. 996-1003 ◽  
Author(s):  
H. Tsuyuki ◽  
S. N. Williscroft
Keyword(s):  
Rainbow Trout ◽  
Lactate Dehydrogenase ◽  
Key Words ◽  
Low Frequency ◽  
Water Velocity ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Very Low Frequency ◽  
Time Required

Rainbow trout (Salmo gairdneri) homozygous for liver lactate dehydrogenase alleles ldhHαA and ldhHαB were artificially propagated and their swimming stamina compared. The time required to fatigue 50% of the HαAHαA phenotypes in fixed water velocity tests was 2.3 times greater on the average than that of HαAHαB phenotypes.Likewise, LDH phenotypes HαAHαA, HαAHαB, and HαAHαB of steelhead trout from the Thompson River were artifically propagated and their swimming stamina compared. In contrast to the rainbow trout, significant differences in stamina among the three phenotypes of steelhead were not evident in the stocks from this river nor between phenotypes HαAHαB and HαBHαB from another stream, the Vedder River, which has a very low frequency of the ldhHαA allele. The stamina of young steelhead from the Thompson River was, however, 3.8 times greater than that of those from the Vedder River. Key words: stamina, LDH, rainbow trout, steelhead, phenotype, swimming, fatigue

Thermal analysis of forced-air and thermosyphon cooling systems for the Inuvik airport expansion

1991 ◽  
Vol 28 (3) ◽  
pp. 399-409 ◽  
Author(s):  
L. B. Smith ◽  
J. P. Graham ◽  
J. F. Nixon ◽  
A. S. Washuta
Keyword(s):  
Thermal Analysis ◽  
Natural Convection ◽  
Key Words ◽  
Thermal Analyses ◽  
Cooling Systems ◽  
Air Ventilation ◽  
Forced Air ◽  
Department Of National Defence ◽  
Raft Foundations ◽  
National Defence

This paper presents a description of thermal analyses of forced-air ventilation and thermosyphon cooling systems, which were carried out in connection with the design of the concrete raft foundations that support hangars and other major structures to be constructed by the Department of National Defence adjacent to the existing airport near Inuvik, N.W.T. The cooling systems are required to prevent heat from the buildings from thawing the ice-rich permafrost present below the site. The analyses identified those parameters that have the most significant effect on the efficiency of each system. Based partially on the results of the analyses, it was decided to utilize air ventilation for cooling. The system is expected to perform satisfactorily under natural convection; however, the design includes a provision to install air blowers, if this should prove necessary in the future. A number of areas in which further research appears useful have been identified. Key words: permafrost, thermal analysis, raft foundation, hangar, ventilated slab, natural convection, thermosyphons.

scholarly journals Examining Patterns of Air Quality Perception: A Cluster Analysis for Southern Chilean Cities

SAGE Open ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 215824401986356 ◽  
Author(s):  
Àlex Boso ◽  
Boris Álvarez ◽  
Christian Oltra ◽  
Álvaro Hofflinger ◽  
Arturo Vallejos-Romero ◽  
...  
Keyword(s):  
Health Care ◽  
Air Pollution ◽  
Cluster Analysis ◽  
Air Quality ◽  
Health Risks ◽  
Public Perception ◽  
Emotional Responses ◽  
Sociodemographic Factors ◽  
Southern Chile ◽  
Las Casas

Various medium-sized cities in southern Chile are saturated by air pollution caused by woodsmoke. In this study, we developed a segmentation model to assess the public’s perceptions, understanding of health risks and emotional responses to poor air quality. To date, this is the first segmentation model dealing with public perception in cities contaminated by woodsmoke. A survey ( N = 489) was conducted in Temuco and Padre las Casas, Chile, which included questions regarding attitudes, sociodemographic factors, and health care behaviors, to obtain information for mitigation initiatives. Through a cluster analysis, three population segments were identified that related differently to environmental pollution, which were constructed based on seven psychosocial variables. Different sociodemographic profiles and self-reported behavioral patterns were found, which should guide policies aimed at improving air quality in cities contaminated by pollution from wood-burning stoves.

scholarly journals Climate-forced air-quality modeling at the urban scale: sensitivity to model resolution, emissions and meteorology

2015 ◽  
Vol 15 (13) ◽  
pp. 7703-7723 ◽  
Author(s):  
K. Markakis ◽  
M. Valari ◽  
O. Perrussel ◽  
O. Sanchez ◽  
C. Honore
Keyword(s):  
Air Quality ◽  
Emission Inventory ◽  
Horizontal Resolution ◽  
Anthropogenic Emissions ◽  
Vertical Resolution ◽  
Post Processing ◽  
Air Quality Model ◽  
Quality Model ◽  
Quality Modeling ◽  
Forced Air

Abstract. While previous research helped to identify and prioritize the sources of error in air-quality modeling due to anthropogenic emissions and spatial scale effects, our knowledge is limited on how these uncertainties affect climate-forced air-quality assessments. Using as reference a 10-year model simulation over the greater Paris (France) area at 4 km resolution and anthropogenic emissions from a 1 km resolution bottom-up inventory, through several tests we estimate the sensitivity of modeled ozone and PM2.5 concentrations to different potentially influential factors with a particular interest over the urban areas. These factors include the model horizontal and vertical resolution, the meteorological input from a climate model and its resolution, the use of a top-down emission inventory, the resolution of the emissions input and the post-processing coefficients used to derive the temporal, vertical and chemical split of emissions. We show that urban ozone displays moderate sensitivity to the resolution of emissions (~ 8 %), the post-processing method (6.5 %) and the horizontal resolution of the air-quality model (~ 5 %), while annual PM2.5 levels are particularly sensitive to changes in their primary emissions (~ 32 %) and the resolution of the emission inventory (~ 24 %). The air-quality model horizontal and vertical resolution have little effect on model predictions for the specific study domain. In the case of modeled ozone concentrations, the implementation of refined input data results in a consistent decrease (from 2.5 up to 8.3 %), mainly due to inhibition of the titration rate by nitrogen oxides. Such consistency is not observed for PM2.5. In contrast this consistency is not observed for PM2.5. In addition we use the results of these sensitivities to explain and quantify the discrepancy between a coarse (~ 50 km) and a fine (4 km) resolution simulation over the urban area. We show that the ozone bias of the coarse run (+9 ppb) is reduced by ~ 40 % by adopting a higher resolution emission inventory, by 25 % by using a post-processing technique based on the local inventory (same improvement is obtained by increasing model horizontal resolution) and by 10 % by adopting the annual emission totals of the local inventory. The bias of PM2.5 concentrations follows a more complex pattern, with the positive values associated with the coarse run (+3.6 μg m−3), increasing or decreasing depending on the type of the refinement. We conclude that in the case of fine particles, the coarse simulation cannot selectively incorporate local-scale features in order to reduce its error.

Coupled Computational Fluid Dynamics (CFD) and Artificial Neural Network (ANN) for Prediction of Traffic-related Air Pollution Infiltration Effects in Hong Kong

2020 ◽  
Author(s):  
Fritz Nieborowski
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Real Life ◽  
Infiltration Rate ◽  
Forced Ventilation ◽  
Real Life Data ◽  
Air Intake ◽  
Forced Air

<div> <p>Improper ventilation of buildings may lead to an accumulation of pollutants indoors. In the case of a room with forced air ventilation and external air intake like most centralized and some home air conditioning units, this study will show CFD simulations of various indoor air quality conditions based on different forced ventilation AC unit intake conditions like common in housing situations like Hong Kong. Especially when close to roadways or other external pollution sources, the positioning of the air intake shows up to have a high significance for the infiltration rate resulting as influence for the indoor air quality as previous research shows (e.g. Zheming Tong et al., 2016). The same is the case for a forced ventilation case like air conditioning units with outside air intake. Research like earlier referenced paper has not been conducted with higher buildings or forced air intake yet. Parametrized CFD-based air quality models with using OpenFoam will be employed to quantify the impact of the air intake location and rate in a 2-dimensional interface on the indoor air quality of a forced ventilated section of a building. The findings of the CFD simulation will be simplified as average indoor air pollution and other external factors. As an approach to predict the estimate indoor infiltration rate, an ANN (Artificial Neuronal Network) will be used, trained and validated with said data. The neural network is supposed to predict the pollutant intake based on fewer and as easier to obtain meteorological parameters and air pollution data. Finally, the ANN predictions of the models will be verified with real life data from other papers. Results will show that a major part of indoor pollutants may emerge indoors and cannot be neglected. In comparison with real life data, it seems the model lacks significant input to predict with high accuracy. </p> </div>

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