Experimental Studies on the Ecology of Intertidal Environments at Heron Island. I. Exclusion of Fish from Beach Rock.

1960 ◽  
Vol 11 (2) ◽  
pp. 241 ◽  
Author(s):  
W Stephenson ◽  
RB Searles
Keyword(s):  
Unit Area ◽  
Chlorophyll Concentration ◽  
Experimental Studies ◽  
Controlling Factor ◽  
General Observation ◽  
Beach Rock ◽  
Surrounding Areas ◽  
Intertidal Environments

The zonation of dominant organisms on the beach rock at Heron Island was reinvestigated following the work of Endean, Stephenson, and Kenny (1956) and three zoning algae were noticed. Field indications suggested the apparent sparsity of the biota was due to the browsing activities of fish. Fish-proof enclosures were constructed, some containing browsing molluscs, and the fauna and flora therein were compared with the surrounding areas by means of detailed general observation, and by estimation of the chlorophyll concentration per unit area of surface. The results confirmed that browsing fish are the most important single controlling factor.

Experimental Studies on the Ecology of Intertidal Environments at Heron Island. II. The Effect of Substratum

1961 ◽  
Vol 12 (2) ◽  
pp. 164 ◽  
Author(s):  
W Stephenson
Keyword(s):  
Survival Rate ◽  
Green Algae ◽  
Brown Alga ◽  
Experimental Studies ◽  
Rock Surface ◽  
Open Surface ◽  
Algal Cover ◽  
Beach Rock ◽  
Per Se ◽  
Intertidal Environments

Different kinds of rocks were cemented to the beach rock at Heron Island both upon the open surface to permit fish browsing, and within cages to prevent it. During a 12-month period, a negligible number of intertidal animals colonized these rocks, and their sparsity upon the surrounding beach rock is evidently not due to a substratum effect per se. Minor effects of the substratum on the flora were noted. On the harder rocks the brown alga, Ralfsia, was a conspicuous newcomer, while green algae were best developed on the calcareous substrata. The intensity of fish browsing was inversely related to the hardness of the rock surface, but the effect was concluded to be an indirect one, hardness affecting the thickness of the algal cover, and this, in turn, affecting the browsing intensity. Hard concrete placed upon the beach 7 years previously was appreciably higher than the general surface, and (after making certain assumptions) it appears that rock is removed by fish browsing to a thickness of about 0.5 mm per year. In a preliminary experiment acorn barnacles were transplanted from the reef crest to the beach rock, and a higher survival rate was observed on caged specimens.

Modeling and verification of selective sludge discharge as the controlling factor for aerobic granulation

2010 ◽  
Vol 62 (10) ◽  
pp. 2442-2449
Author(s):  
A. J. Li ◽  
T. Zhang ◽  
X. Y. Li
Keyword(s):  
Laboratory Experiments ◽  
Growth Form ◽  
Experimental Studies ◽  
Controlling Factor ◽  
Substrate Uptake ◽  
Granulation Process ◽  
Sludge Flocs ◽  
Dense Granules ◽  
Biomass Dynamics ◽  
Aerobic Sludge

Mathematical simulation and laboratory experiments were conducted to investigate the controlling factor for aerobic sludge granulation. A model was used to describe the biomass dynamics during the granulation process. The simulation results indicate that the selective discharge of small and loose sludge flocs is the key controlling factor for granulation. In the experimental studies, tests were conducted with four batch column reactors (BCR) that were seeded with both activated sludge flocs and mature granules. Three different sludge discharge methods were tested, including unselective discharge of mixed sludge, selective discharge of small and slow-settling flocs, and selective discharge of settled dense sludge. The results show that mixed sludge discharge and discharge of dense sludge resulted in disappearance of granules from the reactors. Only selective discharge of small and slow-settling sludge flocs led to complete granulation. Small and loose sludge flocs were found to have a clear advantage over large and dense granules in substrate uptake. It can be concluded that selective discharge of loose flocs removes these competitors in suspended-growth mode from the reactors and makes the substrate more available for uptake and utilization by the biomass in attached-growth form, leading to granulation.

Origin of heterogeneous mafic enclaves by two-stage hybridisation in magma conduits (dykes) below and in granitic magma chambers

2000 ◽  
Vol 91 (1-2) ◽  
pp. 27-45 ◽  
Author(s):  
W. J. Collins ◽  
S. R. Richards ◽  
B. E. Healy ◽  
P. I. Ellison
Keyword(s):  
Magma Chamber ◽  
Plastic Material ◽  
Experimental Studies ◽  
Fracture Network ◽  
Granitic Magma ◽  
Mechanical Mixing ◽  
Two Stage ◽  
General Observation ◽  
Field Evidence ◽  
Stage 1

Field, petrographic and geochemical evidence from the K-feldspar megacrystic Kameruka pluton, Lachlan Fold Belt, southeastern Australia, suggests that complex, multicomponent, mafic microgranular enclaves (MME) are produced by two-stage hybridisation processes. Stage 1 mixing occurs in composite dykes below the pluton, as mafic and silicic melts ascend through shared conduits. Pillows formed in these conduits are homogeneous, fine-to medium-grained stage 1 MME, which typically range from basaltic to granitic compositions that plot as a sublinear array on Harker diagrams. Stage 2 hybridisation occurs in the magma chamber when the composite dykes mix with the resident magma as synplutonic dykes. The stage 2 hybrids also form linear chemical arrays and range from basaltic to granodioritic compositions, the latter resembling the more mafic phases of the pluton. Stage 2 MME are distinguished from stage 1 types by the presence of K-feldspar xenocrysts and a more heterogeneous nature: they commonly contain stage 1 enclaves. Subsequent disaggregation and dispersal of stage 2 hybrid synplutonic dykes within the magma chamber produces a diverse array of multi-component MME.Field evidence for conduit mixing is consistent with published analogue experimental studies, which show that hybrid thermo-mechanical boundary layers (TMBL) develop between mafic and silicic liquids in conduits. A mechanical mixing model is developed, suggesting that the TMBL expands and interacts with the adjacent contrasting melts during flow, producing an increasing compositional range of hybrids with time that are mafic in the axial zone, grading to felsic in the peripheral zones in the conduit. Declining flow rates in the dyke and cooling of the TMBL zones produce a pillowing sequence progressing from mafic to felsic, which explains the general observation of more MME in more silicic hosts.The property of granitic magmas to undergo transient brittle failure in seismic regimes allows analogies with fractured solids to be drawn. The fracture network in granitic magmas consists of through-going ‘backbone’ mafic and silicic ± composite dykes, and smaller ‘dangling’ granitic dykes locally generated in the magma chamber. Stage 1 hybrids form in composite backbone dykes and stage 2 hybrids form where they intersect dangling dykes in the magma chamber. With subsequent shear stress recovery, the host magma chamber reverts to a visco-plastic material capable of flow, resulting in disaggregation and dispersal of these complex, hybrid synplutonic dykes, and a vast array of double and multicomponent enclaves potentially develop in the pluton.

Risk Assessment Studies of Gasketed and Non-Gasketed Bolted Pipe Joints

2002 ◽  
Author(s):  
Muhammad Abid ◽  
David H. Nash
Keyword(s):  
Risk Assessment ◽  
Structural Integrity ◽  
High Reliability ◽  
Experimental Studies ◽  
Pressure Vessels ◽  
General Observation ◽  
Excellent Service ◽  
Pipe Joints ◽  
The Right

Over many years much effort has been made to develop design codes for pressure vessels, pipe-work, flanges and so on to design a system of high structural integrity. In-spite of the efforts the reliability of the system can be adversely affected for many reasons. Poor construction practices, incorrect selection of components such as gasket, improper quality of bolts and surface treatment, incorrect tooling, wrong application, underestimated joint size due to incorrect loading consideration, incorrect use of code, lack of thought to plant use, or a change of use during the life of a plant may make a joint unsuitable. The list is not exhaustive and not all the possible causes of failure may become apparent during commissioning. Failure of a pipe joint means the achievement of a leak rate below a certain maximum limit or the gross failure of the pipeline in which structural integrity is lost. So the high reliability of a system can be obtained if the right joint is selected for an application and factors that affect the reliability should be considered carefully. A very limited work has been done for the risk assessment of bolted pipe joints. At first, the most comprehensive work is done by Det Norske Veritas (DNV) regarding risk assessment of pipe joints. In addition, Webjorn and Thompson have also performed comparative reliability studies for these joints. Both DNV and Webjorn concluded that compact flange joints show better functional safety than conventional gasketed flange joints. Thomson concluded that both the joints are of high integrity and perform well in excellent service under appropriate installation and maintenance conditions. All above studies have been performed based on information and observations. Present author has performed detailed failure mode and effects analysis (FMEA) in the light of above-mentioned studies, idustrial surveys, analysis, experimental work and subsequent observations. The aim of the study was to increase the reliability knowledge about the gasketed and non-gasketed flanged pipe joints and thereby to increase the basis for finding the optimal pipe connection based on general observation and experimental studies performed.

EFFECT OF SHADE ON PHOTOSYNTHETIC PIGMENTS IN THE TROPICAL ROOT CROPS: YAM, TARO, TANNIA, CASSAVA AND SWEET POTATO

1998 ◽  
Vol 34 (3) ◽  
pp. 301-312 ◽  
Author(s):  
M. JOHNSTON ◽  
I. C. ONWUEME
Keyword(s):  
Sweet Potato ◽  
Unit Area ◽  
Chlorophyll Concentration ◽  
Leaf Size ◽  
The Other ◽  
Leaf Chlorophyll ◽  
Root Crops ◽  
Shade Tolerant Species ◽  
Harvesting Systems ◽  
Proportional Increase

Plants of yam, taro, tannia, cassava and sweet potato were raised under shade or in full sunlight and the effect of shade on leaf chlorophyll and carotenoids was examined to determine and compare the relative shade tolerance and adaptability of the var ious species. All five species of root crops adapted to shade. The chlorophyll concentration was higher, while the chlorophyll a:b ratio, carotenoids per unit chlorophyll and the weight per unit area of leaf were lower in the shade than in the su n in yam, tannia, taro, cassava and sweet potato. All species had larger leaves and more chlorophyll per leaf in the shade. The extent of the changes, however, differed between species. The aroids (taro and tannia) appeared to be shade-tolerant species as their chlorophyll a:b ratios changed less than those of the other species in the shade, suggesting that their light-harvesting systems may be normally adapted to shade conditions. Taro and tannia also adapted to shade by a greater proportional i ncrease in leaf size, a smaller reduction in leaf weight per unit area and a greater proportional increase in chlorophyll and carotenoids per leaf than the other species. Yam compensated for shade by having a large proportional increase in leaf size and a ppeared to be moderately tolerant of shade. Sweet potato and cassava appeared to be the least tolerant of shade of the major tropical root crops.

scholarly journals Granulated asphalt mix based on industrial and domestic waste

2018 ◽  
Vol 251 ◽  
pp. 01028
Author(s):  
Alexey Ignatiev ◽  
Denis Gerasimov ◽  
Igor Golikov ◽  
Valeriy Gotovtsev
Keyword(s):  
Asphalt Concrete ◽  
Experimental Studies ◽  
Test Methods ◽  
Raw Material ◽  
Concrete Mixture ◽  
Waste Production ◽  
Asphalt Mix ◽  
Mineral Powder ◽  
Method Of Production ◽  
Surrounding Areas

The paper presents the results of experimental studies to identify the possibility of using large-tonnage industrial mineral waste in the production of asphalt concrete mixtures. As a raw material for the production of asphalt used phosphogypsum - waste production of phosphoric acid, resulting from the processing of apatite. The reserves of this product are measured in millions of tons and are constantly replenished, stored in open dumps, representing a serious threat to the environmental situation in the surrounding areas. Phosphogypsum is a mineral powder material, the dispersion characteristics of which correspond to the mineral powder in the production of asphalt concrete. The method of production of granulated as-falto-concrete mixture developed by the authors of the article by the method of rolling involves the use of a significantly higher content of expensive mineral powder in comparison with typical mixtures. Therefore, the use of cheap phosphogypsum for these purposes is very attractive. However, the first attempts to obtain a granulated product based on phosphogypsum were unsuccessful - the asphalt-concrete mixture did not withstand the effects of moisture. Further studies allowed us to solve the problem of material resistance by modifying bitumen with polyethylene terephthalate, one of the most common household plastic waste. The subject of the article is devoted to the development of prescription and regime parameters of the process of obtaining new material. Test methods for asphalt concrete are strictly standardized in connection with which standard techniques were used. As a result of the research, an asphalt-concrete mixture was obtained, surpassing typical materials in many performance characteristics and allowing to solve a global environmental problem.

Radiation Damage, Contrast and Statistics in High Resolution Biological Electron Microscopy

1970 ◽  
Vol 28 ◽  
pp. 260-261
Author(s):  
Robert M. Glaeser
Keyword(s):  
High Resolution ◽  
Particle Flux ◽  
Unit Area ◽  
Signal To Noise ◽  
Resolution Image ◽  
High Resolution Image ◽  
Pass Through ◽  
Counting Statistics ◽  
The Relationship ◽  
Picture Element

It is well known that a large flux of electrons must pass through a specimen in order to obtain a high resolution image while a smaller particle flux is satisfactory for a low resolution image. The minimum particle flux that is required depends upon the contrast in the image and the signal-to-noise (S/N) ratio at which the data are considered acceptable. For a given S/N associated with statistical fluxtuations, the relationship between contrast and “counting statistics” is s131_eqn1, where C = contrast; r2 is the area of a picture element corresponding to the resolution, r; N is the number of electrons incident per unit area of the specimen; f is the fraction of electrons that contribute to formation of the image, relative to the total number of electrons incident upon the object.

Reconstruction of Objects from their Projections Using Orthogonal Functions

1973 ◽  
Vol 31 ◽  
pp. 268-269
Author(s):  
Elrnar Zeitler
Keyword(s):  
Unit Area ◽  
Three Dimensional ◽  
One Dimension ◽  
Spatial Density ◽  
Dimensional Representation ◽  
Orthogonal Functions ◽  
Object A ◽  
Plane Normal ◽  
Dimensional Object ◽  
Spatial Density Distribution

Considering any finite three-dimensional object, a “projection” is here defined as a two-dimensional representation of the object's mass per unit area on a plane normal to a given projection axis, here taken as they-axis. Since the object can be seen as being built from parallel, thin slices, the relation between object structure and its projection can be reduced by one dimension. It is assumed that an electron microscope equipped with a tilting stage records the projectionWhere the object has a spatial density distribution p(r,ϕ) within a limiting radius taken to be unity, and the stage is tilted by an angle 9 with respect to the x-axis of the recording plane.

Morphometric SEM study of the effects of ACTH on endothelial fenestrae in the rat adrenal cortex

1984 ◽  
Vol 42 ◽  
pp. 234-235
Author(s):  
J. Curtis ◽  
K. S. Schwartz ◽  
R. P. Apkarian
Keyword(s):  
Anterior Pituitary ◽  
Lipid Droplets ◽  
Adrenocorticotropic Hormone ◽  
Unit Area ◽  
High Density Lipoproteins ◽  
Capillary Endothelium ◽  
Zona Fasciculata ◽  
Sem Study ◽  
Saline Vehicle ◽  
Scanning Electron

A scanning electron microscope (SEM) study was made of the effect of adrenocorticotropic hormone (ACTH) on the size and numbers of fenestrae/unit area in the capillary endothelium of the zona fasciculata (ZF) of the rat adrenal. The stimulatory effect of ACTH on cholesterol uptake via high density lipoproteins in the rat and evidence for the secretion of glucocorticoids by exocytosis of lipid droplets described by Rhodin suggest that endothelial change may accompany these transport phenomena.Twelve rats received two Dexamethasone (DEX) ip injections (25 μg DEX/100 g body wt.), the first at 8 PM and the second at 8 AM the next day, to inhibit the release of endogenous ACTH by the anterior pituitary. The animals were then divided into two groups. Six animals received only saline vehicle and six rats received ACTH (100 ng/100 g body wt.).

Sign in / Sign up

Export Citation Format

Share Document