Spatial and Temporal Patterns in Macrobenthic Stream Diversity

1976 ◽  
Vol 33 (6) ◽  
pp. 1261-1270 ◽  
Author(s):  
Brigitte G. E. de March
Keyword(s):  
Particle Size ◽  
Related Species ◽  
High Variability ◽  
Particle Sizes ◽  
Spatial And Temporal Patterns ◽  
Mean Particle Size ◽  
Faunal Assemblages ◽  
Number Of Species ◽  
Stream Community ◽  
The Relationship

The relationship between the characteristics of a stream community and sediments were studied for 1 yr in a small unpolluted river with a morainal substrate. Recognizable faunal assemblages were associated with silt or silt fill, sand or sand fill, and large boulders. The fauna in sediments of mean particle sizes coarser than sand but finer than boulders was characterized by a high variability due largely to temporal successions of morphologically related species. It was found that the number of species was directly proportional to mean particle size (in [Formula: see text] units) in spring when the sediments were well sorted, but the relationship broke down as the sediment interstices filled in. In late fall when the sediments were badly sorted, the number of species is perhaps more related to the sorting coefficient of the sediments. The relevance of these findings to studies of pollution is discussed.

Production of quicklime from Ashaka limestone through calcination process

2021 ◽  
Vol 1 (2) ◽  
pp. 041-048
Author(s):  
Benson Chinweuba Udeh
Keyword(s):  
Particle Size ◽  
Critical Value ◽  
Operating Conditions ◽  
Quadratic Model ◽  
Particle Sizes ◽  
Calcination Process ◽  
Process Effects ◽  
Effects Of Temperature ◽  
The Difference ◽  
The Relationship

This study is on the production of quicklime from Ashaka limestone through calcination process. Effects of temperature, particle size and time on quicklime yield were determined. The experiment was carried out at temperatures of 800, 900, 1000, 1100 and 1200 0C, particle sizes of 80mm, 90mm, 100mm, 300mm and 425mm and times of 0.5hr, 1hr, 2hrs, 3hrs and 4hrs. Analyses of the results showed that quicklime was successfully produced from Ashaka limestone through the calcination process. Quadratic model adequately described the relationship between quicklime yield and calcination factors of temperature, particle size and time. Recorded model F-value of 134.35 implies that the model is significant. The predicted R² of 0.9597 is in reasonable agreement with the adjusted R² of 0.9844; the difference is less than the critical value of 0.2. Optimum yield of 73.48% was obtained at optima operating conditions; temperature of 1000 0C, particle size of 90 µm and time of 3 hrs.

The Relationship Between Colliery-waste Particle Sizes and Plant Growth

1974 ◽  
Vol 1 (4) ◽  
pp. 281-284 ◽  
Author(s):  
Christopher G. Down
Keyword(s):  
Particle Size ◽  
Plant Growth ◽  
Water Retention ◽  
Size Range ◽  
Growth Period ◽  
Dry Weight ◽  
Particle Sizes ◽  
Small Particles ◽  
The Relationship ◽  
Water Holding

Seed germination and dry-weight production in Lolium perenne were examined in relation to growth on 12-years-old colliery waste separated into seven size-fractions. The size-range was from more than 4,000 μ to less than 125 μ, and the growth period was up to 30 days. Germination percentages after 6 days generally increased with decreasing particle-size, as did dry-weight. Shoot : root ratios also showed an inverse relationship with particle size.After 30 days there was no distinction between dryweights on different particle sizes, except that on the largest fractions it had been found impossible to keep the plants alive. Problems of water-holding capacity are discussed, and the significance of soil particle-size in revegetation work is examined, it being concluded that an admixture of small particles is important for water retention and plant growth.

scholarly journals The Influence of the Gold Particle Size on the Catalytic Oxidation of 5-(Hydroxymethyl)furfural

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 342 ◽  
Author(s):  
Oliver Schade ◽  
Paolo Dolcet ◽  
Alexei Nefedov ◽  
Xiaohui Huang ◽  
Erisa Saraçi ◽  
...  
Keyword(s):  
Particle Size ◽  
Functional Groups ◽  
Chemical Reduction ◽  
Large Fraction ◽  
Particle Sizes ◽  
Mean Particle Size ◽  
Hydroxymethyl Furfural ◽  
Highly Active ◽  
Surface Steps ◽  
Aldehyde Oxidation

For the production of chemicals from biomass, new selective processes are required. The selective oxidation of 5-(Hydroxymethyl)furfural (HMF), a promising platform molecule in fine chemistry, to 2,5-furandicarboxylic acid (FDCA) is considered a promising approach and requires the oxidation of two functional groups. In this study, Au/ZrO2 catalysts with different mean particle sizes were prepared by a chemical reduction method using tetrakis(hydroxymethyl)phosphonium chloride (THPC) and tested in HMF oxidation. The catalyst with the smallest mean particle size (2.1 nm) and the narrowest particle size distribution was highly active in the oxidation of the aldehyde moiety of HMF, but less active in alcohol oxidation. On the other hand, increased activity in FDCA synthesis up to 92% yield was observed over catalysts with a larger mean particle size (2.7 nm), which had a large fraction of small and some larger particles. A decreasing FDCA yield over the catalyst with the largest mean particle size (2.9 nm) indicates that the oxidation of both functional groups require different particle sizes and hint at the presence of an optimal particle size for both oxidation steps. The activity of Au particles seems to be influenced by surface steps and H bonding strength, the latter particularly in aldehyde oxidation. Therefore, the presence of both small and some larger Au particles seem to give catalysts with the highest catalytic activity.

An initial test of a method for the estimation of real mean particle size from shadowed samples

1985 ◽  
Vol 31 (7) ◽  
pp. 604-607
Author(s):  
J. H. M. Willison
Keyword(s):  
Particle Size ◽  
Present Method ◽  
Particle Sizes ◽  
Initial Test ◽  
Small Particles ◽  
Mean Particle Size ◽  
Sample Rotation ◽  
Mean Diameter ◽  
The Mean

During shadowing, a "cap" of metal develops on small particles. This cap increases, apparent particle width (measured normal to the shadowing direction) by an extent which cannot be predetermined. The extent of this increase in particle size (here defined as the "cap," X) is estimated in the present method by using opposite (180° sample rotation) bidirectional shadowing. It is argued that the bidirectional cap is the sum of the two unidirectional caps, and therefore that X = 2A − (B + C), where A is the mean bidirectionally shadowed particle size, and B and C are the two mean unidirectionally shadowed particle sizes. As a validation of the method, the mean diameter of air-dried ferritin was estimated and the results appear to confirm the hypothesis (mean diameter by present method, 10.7 ± 0.2 nm; mean diameter by previous methods, 10.89 nm).

Lime Brust of Sintering Bricks of Purple Sandy Shale: the Effect of Limestone Particle Size

2011 ◽  
Vol 250-253 ◽  
pp. 46-49
Author(s):  
Zhi Gang Feng ◽  
Zhen Ping Tang ◽  
Hui Juan Li
Keyword(s):  
Particle Size ◽  
Hunan Province ◽  
Particle Sizes ◽  
Sintering Process ◽  
Critical Content ◽  
Production Practice ◽  
Sandy Shale ◽  
Free Cao ◽  
The Relationship

Simulating current sintering process in local brickkilns, Hengyang region, Hunan Province, China, at 800°C, througt indoor sintering experiment on a series of brick samples of purple sandy shale, in which particle sizes of limestone are >-1Φ, >0Φ, >1Φ, >2Φ, >3Φ and >4Φ, respectively, it is concluded that the following: (1) Limestone granularity is a crucial factor affecting the quality of sintering bricks of purple sandy shale. Under different particle sizes, the critical content of limestone causing lime brust of sintering bricks is distinct, and lowers with the increasing in limestone granularity. (2) When limestone granularity is different, its impact way on the quality of sintering bricks is also distinct. The more coarse limestone granularity is, the more concentrative the swelling stress produced by the hydration of free CaO is, the more easily lime brust occurs. On the contrary, the more fine limestone granularity is, the more dispersive the swelling stress is, there is the more help to reduce or eliminate the occurrence of lime brust. (3) In view of the relationship between limestone granularity and the critical content of limestone giving rise to lime brust of sintering bricks, the production practice can be effectively guided.

FURTHER OBSERVATIONS ON THE ABSORPTION OF VITAMIN A

PEDIATRICS ◽  
1950 ◽  
Vol 5 (3) ◽  
pp. 425-436
Author(s):  
J. M. LEWIS ◽  
SIDNEY Q. COHLAN ◽  
ANGELINA MESSINA
Keyword(s):  
Particle Size ◽  
Vitamin A ◽  
Particle Sizes ◽  
Small Particle Size ◽  
Fish Liver ◽  
Butter Fat ◽  
Fat Globule ◽  
Relationship Of ◽  
High Degree ◽  
The Relationship

Experiments carried out on infants revealed that vitamin A, as it occurs naturally in milk, was more effectively absorbed than when administered in an oily vehicle, but not quite as well absorbed as when given in an "aqueous" preparation. The high degree of absorbability of vitamin A in milk is due to the relatively small particle size of the butter fat globule. By reducing the particle size of a fish liver oil preparation (oleum percomorphum) to 1 to 2 µ by homogenization into milk or water, the absorption of vitamin A was considerably enhanced in children and in rats. The relationship of the particle size of the vehicle of vitamin A to absorption is further demonstrated by the results of the administration in children and in rats of three vitamin A preparations of varying particle size. Thus, the highest absorption occurred following the administration of a preparation containing particle size of submicroscopic proportion ("aqueous"); the lowest absorption resulted following the preparation containing particles macroscopic in size (oil) and intermediate absorption was observed following the use of a preparation containing particle sizes varying from 1 to 20 µ (emulsion). Similarly, in a child having cystic fibrosis of the pancreas, the absorption of vitamin A was dependent upon the particle size of the vehicle employed.

Research on the Low Temperature Degradation Resistance of TiN/3Y-TZP

2009 ◽  
Vol 79-82 ◽  
pp. 287-290
Author(s):  
Jing Sun ◽  
Bao Kun Han ◽  
Xing Hua Yang ◽  
Chuan Zhen Huang
Keyword(s):  
Particle Size ◽  
Composite Materials ◽  
Low Temperature ◽  
Aging Temperature ◽  
Particle Sizes ◽  
Aging Rate ◽  
The Matrix ◽  
Key Factor ◽  
The Relationship ◽  
In Virtue Of

The composite materials TiN/3Y-TZP, 3Y-TZP doped by TiN with different contents and particle sizes, were fabricated through the same hot-pressing techniques. Compared with 3Y-TZP, the low temperature degradation resistance of TiN/3Y-TZP aged at the temperature from 170°C to 350°C in air for 50 h was investigated in virtue of XRD and SEM in the experiment. For TiN/3Y-TZP and 3Y-TZP, the maximum aging rate all occurs at 220°C. The addition of TiN can availably improve the low temperature degradation resistance of 3Y-TZP at different aging temperatures, but cannot change the relationship between the aging rate and the aging temperature. For TiN/3Y-TZP, the matrix particle size is the key factor responsible for its low temperature degradation resistance.

Application of X-Ray Fluorescence Analysis to Process Control

1961 ◽  
Vol 5 ◽  
pp. 486-499 ◽  
Author(s):  
F. Bernstein
Keyword(s):  
Particle Size ◽  
Process Control ◽  
Sampling Technique ◽  
Fluorescence Analysis ◽  
Particle Sizes ◽  
X Ray ◽  
Direct Sampling ◽  
Precision And Accuracy ◽  
Relationship Of ◽  
The Relationship

AbstractThe application of X-ray fluorescence-analysis methods to process control is discussed. Various methods of sample preparation are reviewed and compared. The use of the direct sampling technique is discussed and consideration is given to the effects of particle size on precision and accuracy of analytical results. The mechanism of these effects if presented, and some general principles concerning the relationship of fluorescent intensities and particle sizes of pure materials and mixtures are derived. Examples of particle-size effects in cement and mining applications are illustrated.

Investigation of Relationship Between Sugar Yield and Particle Size in Biofuel Manufacturing

2017 ◽  
Author(s):  
Rajkamal Kesharwani ◽  
Xiaoxu Song ◽  
Yang Yang ◽  
Zeyi Sun ◽  
Meng Zhang ◽  
...  
Keyword(s):  
Particle Size ◽  
Design Of Experiments ◽  
Sugar Yield ◽  
Critical Parameters ◽  
Particle Sizes ◽  
Specific Process ◽  
Different Types ◽  
Optimal Configurations ◽  
The Relationship ◽  
Design Experiments

Biofuel manufacturing consists of two major processes, i.e., feedstock preprocessing and bioconversion. The preprocessing includes size reduction and pelleting. The bioconversion includes pretreatment, hydrolysis, and fermentation. Various studies have been implemented for these two processes. Most existing literature focuses on a specific process, while very few of them consider the possible interactions between the two processes. In this paper, we investigated the relationship between the particle size in feedstock preprocessing and the sugar yield (proportional to biofuel yield) in bioconversion. The method of design of experiments was used to design experiments and analyze the experimental results of sugar yield with different particle sizes for three different types of biomass. Critical parameters that significantly influence the sugar yield were identified. The optimal configurations of the particle size were recommended.

Study on Matching Ability between Cement Particle Size and Permeability in the Process of Oil Reservoir Plugging

2013 ◽  
Vol 807-809 ◽  
pp. 2544-2549
Author(s):  
Jiu Hong Feng ◽  
Yang Liu
Keyword(s):  
Particle Size ◽  
Research Result ◽  
Size Optimization ◽  
Oil Reservoir ◽  
Cement Particle ◽  
Particle Sizes ◽  
Success Rates ◽  
The Relationship ◽  
Technical Studies

In order to satisfy the plugging demands of injecting the cement plugging agent into reservoirs with different radial depths, the technical studies of cement particle size optimization should be conducted. Through indoor experiment, the relationship between cement particle size and permeability was investigated by both macroscopic and microcosmic analysis. It is observed that the reservoirs which permeabilities are within 50~200mD are matching well with the cement agents which particle sizes are less than 5μm. And the permeabilities within 200~400mD are matching well with the cement agents which particle sizes are within 5~10μm, the permeabilities within 400~700mD are matching well with the cement agents which particle sizes are within 10~20μm, the permeabilities are above 700mD are matching well with the cement agents which particle sizes are more than 20μm. The plugging success rates of all the matching experiments are exceeding 90%. This research result is important to direct the plugging operation in the field.

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