scholarly journals Analysis of Fine Dust Removal Time Using Circular Hole Electrodes of Various Sizes by Corona Discharge

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1956
Author(s):  
Do-Hyun Kim ◽  
Min-Soo Kim ◽  
Muhammad Adil Khan ◽  
Hee-Je Kim
Keyword(s):  
Corona Discharge ◽  
Circular Hole ◽  
Laboratory Experiments ◽  
Hole Diameter ◽  
The Other ◽  
Fine Dust ◽  
Removal Time ◽  
Air Purifier ◽  
Clean Air ◽  
Total Volatile Organic Compounds

Corona discharge technology is used widely for air purification in laboratory experiments and industry. On the other hand, corona discharge technology has the disadvantage of requiring large-sized electrodes. Therefore, research is needed to reduce the size of the electrodes. In this study, circular hole aluminum electrodes and an air purifier system were designed to reduce the size of the electrodes. Several sets of power conversions were performed to generate a corona discharge. The system consisted of a half bridge inverter, step-up transformer, and Cockcroft Walton circuit. The range of input and output voltages was 30–70 V and 20–25 kV, respectively. A corona discharge was generated by the output voltage. The system could remove smoke in less time with a combination of 13 kHz and an electrode with a hole diameter of 0.2 cm than with the other combinations. The electrode hole diameter affected the removal time of species such as hydrogen carbon hydrogen oxygen (HCHO, formaldehyde), total volatile organic compounds (TVOC), and fine dust, which was confirmed by laboratory experiments. Mathematical derivation and experiments were carried out to prove the validity of the approach; the Clean Air Delivery Rate (CADR) index was 480 μm/m3.

Capture of conspecific planktonic larvae by the suspension-feeding gastropod Crepipatella peruviana: association between adult and larval size

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
G A Rivera-Figueroa ◽  
J A Büchner-Miranda ◽  
L P Salas-Yanquin ◽  
J A Montory ◽  
V M Cubillos ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Larval Mortality ◽  
Feeding Preference ◽  
The Other ◽  
Suspension Feeding ◽  
Adult Size ◽  
Free Living ◽  
Larval Size ◽  
Suspension Feeders ◽  
Planktonic Larvae

ABSTRACT Free-living, planktonic larvae can be vulnerable to capture and ingestion by adult suspension-feeders. This is particularly the case for larvae that settle gregariously in benthic environments where suspension-feeders occur at high densities. Larvae of gregarious suspension-feeding species are at particularly high risk, as adults of their own species often serve as cues for metamorphosis. We conducted laboratory experiments to assess the extent to which adults of the suspension-feeding caenogastropod Crepipatella peruviana would capture and ingest their own larvae. Experiments were conducted with adults of different sizes, with larvae of different ages and sizes, and in the presence or absence of phytoplankton. Adults captured larvae in all experiments. The presence of microalgae in the water did not influence the extent of larval capture. On average, 39% of larvae were captured during the 3-h feeding periods, regardless of adult size. However, up to 34% of the larvae that were captured on the gill were later discarded as pseudofaeces; the other 64% were ingested. The extent of capture by adults was not related to adult size, or to larval size and, thus, to larval age. Our results suggest that the filtration of congeneric larvae by adult C. peruviana is a result of accidental capture rather than a deliberate feeding preference. Such ingestion could, however, still be an important source of larval mortality, especially when the advanced larvae of this species are searching for a suitable substrate for metamorphosis.

scholarly journals An Application of Hankel Transforms in Axially Symmetric Potential Flow

1956 ◽  
Vol 9 (3) ◽  
pp. 128-131
Author(s):  
A. G. Mackie
Keyword(s):  
New York ◽  
Incompressible Fluid ◽  
Circular Hole ◽  
Potential Flow ◽  
Fourier Transforms ◽  
The Other ◽  
Axially Symmetric ◽  
Symmetric Potential ◽  
Physical Interest ◽  
Hankel Transforms

In his book on Hydrodynamics, Lamb obtained a solution for the potential flow of an incompressible fluid through a circular hole in a plane wall. More recently Sneddon (Fourier Transforms, New York, 1951) obtained Lamb's solution by an elegant application of Hankel transforms.Since the streamlines in this solution are symmetric about the wall, it is not of particular physical interest. In this note, Sneddon's method is used to give a solution in which the fluid is infinite in extent on one side of the aperture but issues as a jet of finite diameter on the other side.

scholarly journals A Hooked-Collar for Bridge Piers Protection: Flow Fields and Scour

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1251 ◽  
Author(s):  
Su-Chin Chen ◽  
Samkele Tfwala ◽  
Tsung-Yuan Wu ◽  
Hsun-Chuan Chan ◽  
Hsien-Ter Chou
Keyword(s):  
Laboratory Experiments ◽  
Horseshoe Vortex ◽  
Flow Fields ◽  
Bridge Pier ◽  
The Other ◽  
Bridge Piers ◽  
Vortex Strength ◽  
Numerical Tests ◽  
Scour Hole ◽  
New Type

A new type of collar, the hooked-collar, was studied through experiments and numerical methods. Tests were conducted using a hooked collar of a width of 1.25b and a height of 0.25b, where b is the bridge-pier width. The hooked-collar efficiency was evaluated by testing different hooked-collar placements within the bridge-pier, which were compared to the bridge-pier without any collar. A double hooked-collar configuration, one placed at the bed level and the other buried 0.25b, was the most efficient at reducing the scour hole. In other cases, a hooked-collar positioned 0.25b above the bed slightly reduced the scour hole and had similar scour patterns when compared to the pier without the hooked-collar. The flow fields along the vertical symmetrical plane in the experiments are also presented. Laboratory experiments and numerical tests show that maximal downflow is highly reduced along with a corresponding decrease in horseshoe vortex strength for the experiments with the hooked-collar, compared to cases without the hooked-collar. The flow fields reveal that the maximum turbulent kinetic energy decreases with the installation of the hooked-collar.

scholarly journals How Quickly are Road-killed Snakes Scavenged? Implications for Underestimates of Road Mortality

2011 ◽  
Vol 127 (2) ◽  
pp. 184-188 ◽  
Author(s):  
BRETT A. DEGREGORIO ◽  
THOMAS E. HANCOCK ◽  
DAVID J. KURZ ◽  
SAM YUE
Keyword(s):  
United States ◽  
Population Dynamics ◽  
Community Composition ◽  
The United States ◽  
The Other ◽  
Road Mortality ◽  
Correction Factors ◽  
Significant Extent ◽  
Removal Time ◽  
Maritime Forest

Abstract Annually, millions of snakes are killed on roads in the United States. Because of their potential abundance and ease of collection, many researchers have used road-killed snakes to examine community composition, movement patterns, and population dynamics. However, few previous studies have accounted for snake carcasses that are removed from roads by scavengers. Snake carcasses were placed at randomly selected locations along 2 km of road, one traversing maritime forest and the other surrounded by dune habitat. Carcasses in forested habitat were removed more often (100% vs 40%) and more quickly (8 hr vs 11 hr) than those placed in dune habitat. Half of the carcasses (50%) were removed within eight hours of placement and all carcasses were removed at night. Species and size of carcasses did not affect removal time. Removal time and scavenging intensity of snake carcasses most likely varies across regions and habitats. Furthermore, because scavenging appears to occur quickly and to such a significant extent, it may confound results of studies examining patterns of road-mortality. Thus, investigators that use data from road-killed snakes would benefit from a concurrent investigation of scavenging and application of appropriate correction factors to avoid underestimation of snake mortality.

Effects of juvenile hormone mimics on the codling moth Cydia Pomonella (L.) (Lep., Olethreutidae)

1973 ◽  
Vol 63 (1) ◽  
pp. 7-16 ◽  
Author(s):  
I. Gelbič ◽  
F. Sehnal
Keyword(s):  
Juvenile Hormone ◽  
Laboratory Experiments ◽  
Cydia Pomonella ◽  
Codling Moth ◽  
The Other ◽  
Wide Range ◽  
Juvenile Hormone Analogues ◽  
Juvenile Hormone Mimics

AbstractLaboratory experiments with juvenile hormone analogues on Cydia pomonella (L.) showed that Cecropia C17 juvenile hormone (methyl 10,ll-epoxy-3,7,ll-trimethyl-2,6-dodecadienoate) was the most active of the 28 compounds tested. When applied to four-hour-old eggs at 0.1 μg/egg, the hormone caused 100% failure in embryogenesis, while the other compounds were at least five times less effective. Depending on the time since ecdysis and the dose, juvenile hormone mimics applied to last-instar larvae resulted in a wide range of intermediate forms. Against three-day-old last-instar larvae, the Cecropia C17 hormone gave 100% inhibition of development at a dose of 1 μg/larva, while three other compounds (methyl 10,11-epoxy-3,7,11-trimethyl-2,6-dodecadienoate, ethyl 11-chloro-3,7,11-trimethyl-2-dodecenoate and ethyl 3,7,11-tri-methyl-2,4-dodecadienoate) gave the same effect at 2–5 μg/larva. Against newly emerged adults, the last two compounds at 10–50 μg/insect reduced fecundity and fertility to 0–81% and 0–50%, respectively, of their normal levels.

GERMINATION OF ALFALFA VARIETIES IN SOLUTIONS OF VARYING OSMOTIC PRESSURE AND RELATIONSHIP TO WINTER HARDINESS

1959 ◽  
Vol 39 (3) ◽  
pp. 384-394 ◽  
Author(s):  
D. H. Heinrichs
Keyword(s):  
Sodium Chloride ◽  
Osmotic Pressure ◽  
Laboratory Experiments ◽  
Reliable Method ◽  
Winter Hardiness ◽  
The Other ◽  
General Tendency ◽  
Salt Solutions ◽  
Sodium Chloride Solutions ◽  
Alfalfa Varieties

Two laboratory experiments were conducted to evaluate the reliability of amount of germination in solutions of varying osmotic pressure, as a means of separating alfalfa varieties into winter-hardiness classes. In one test 23 varieties or strains were studied, and in the other 36. It was found that significant differences exist between certain alfalfa varieties in their ability to germinate in sucrose or sodium chloride solutions of 3, 6, and 9 atmospheres. There is a general tendency for non-hardy varieties to germinate more rapidly and more completely than hardy ones but there are many exceptions to this trend. Germination in solutions of 6 atmospheres osmotic pressure at 5 days gave the best separation of varieties on the basis of their ability to germinate. Germination was generally better in solutions of sucrose at 6 atmospheres osmotic pressure than in solutions of sodium chloride of the same osmotic pressure but several varieties germinated equally well in either solution. The results indicate that germinating alfalfa in sugar or salt solutions is not a reliable method for differentiating alfalfa varieties into winter hardiness classes.

Thinking orientation and preference for research methodology

2016 ◽  
Vol 33 (6) ◽  
pp. 437-446 ◽  
Author(s):  
Feisal Murshed ◽  
Yinlong Zhang
Keyword(s):  
Research Methodology ◽  
Design Methodology ◽  
Laboratory Experiments ◽  
Qualitative Methodology ◽  
Marketing Research ◽  
Cross Cultural ◽  
The Other ◽  
Content Type ◽  
Holistic Thinking ◽  
Practical Implications

Purpose This research aims to investigate how preference for marketing research methodology (quantitative vs qualitative) is contingent on the thinking orientation (analytic vs holistic) of the researchers. Design/methodology/approach Thinking orientation was measured and then manipulated in laboratory experiments. Cross-cultural evidence was sought by comparing Western and East Asian participants. Findings Results demonstrate that researchers with an analytic (holistic) thinking orientation tend to perceive quantitative (qualitative) methodology more favorably. Further, the need to offer reasons in support of the choice strengthened the effect of thinking orientation. Practical implications Understanding researchers’ preferences for one research methodology over the other has broad relevance for external constituents, as it involves a great deal of managerial commitment in terms of time and money and can affect the results of the research. Originality/value This is the first study to investigate factors that underlie researchers’ choice regarding research methodology, and it also extends the literature on analytic versus holistic thinking orientation in the marketing field.

scholarly journals Limiting stress states in granular avalanches

1998 ◽  
Vol 26 ◽  
pp. 272-276 ◽  
Author(s):  
Y.C. Tai ◽  
J.M.N.T. Gray
Keyword(s):  
Stress State ◽  
Numerical Methods ◽  
Granular Material ◽  
Laboratory Experiments ◽  
Complex Geometry ◽  
The Other ◽  
Two Dimensional ◽  
Singular Surfaces ◽  
Rapid Convergence ◽  
Stress States

The Savage-Hutter theory for granular avalanches assumes that the granular material is in either of two limiting stress states, depending on whether the motion is convergent or divergent. At transitions between convergent and divergent regions, a jump in stress occurs, which necessarily implies that there is a jump in the avalanche velocity and/or its thickness. In this paper, a regularizaron scheme is used, which smoothly switches from one stress state to the other, and avoids the generation of such singular surfaces. The resulting algorithm is more stable than previous numerical methods but shocks can still occur during rapid convergence in the run-out zone. Results are presented from two-dimensional calculations on complex geometry which illustrate that some necking features observed in laboratory experiments can be explained by the regularized Savage-Hutter model.

scholarly journals Clothing for use in clean-air environments

1976 ◽  
Vol 77 (2) ◽  
pp. 267-269 ◽  
Author(s):  
R. P. Clark ◽  
B. J. Mullan
Keyword(s):  
The Other ◽  
Clean Air ◽  
Micro Organisms ◽  
Burns Unit ◽  
Disposable Plastic

SummaryDisposable plastic two-piece suits were compared with conventional cotton suits, gowns, and plastic aprons by nurses in a burns unit. The plastic suits allowed fewer micro-organisms to be dispersed into the environment than the other garments but were less comfortable.

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