Bottom Entry Research Articles

A low-cost, durable, submersible light trap and customisable LED design for pelagic deployment and capture of fish parasite Salmincola sp. copepodids

Documenting species invasions and assessments of ecological changes depend on detection. Here, we present a simple design of a plankton light trap with specific wavelength LEDs and modifications. We used PVC pipe to create standardised small, rigid, low-cost traps that can be deployed in lentic habitats. With a cost of under $30 US each, including lights and rechargeable batteries, our traps are affordable without the need for disposable chemical lights. These small traps rely on a vacuum to retain contents upon retrieval, eliminating complicated closing mechanisms and allowing bottom entry. Our design includes submersible LED lights that can withstand pressures of at least 5 atm. We expect that the included instructions for underwater light construction and rubber weights using sand may be broadly applicable. However, we designed and field-tested our traps focusing on the detection and capture of the infective copepodid lifestage of a freshwater parasitic copepod, Salmincola californiensis. This lifestage had previously only been observed by rearing in a laboratory setting and is of concern due to continued spread outside of its native range and detrimental impacts on salmonids, especially in freshwater reservoirs. We used a 445–450 nm wavelength LED light for capturing Salmincola copepodids, but the light design can be modified to any readily available LED and heat sink to attract other target organisms. In our case, the overall affordability of the trap and components allowed for the extensive trapping needed to capture and map the occurrence of rarely-observed species and lifestages, such as the copepodids of S. californiensis. In general, increasing the number of traps that can be deployed within or across sites can aid in the spatial comparisons of plankton distributions needed in studies of ecology and species life histories. Light traps may aid in the detection of introduced zooplankton, such as S. californiensis, outside of their native range and associated plankton community changes.

Construction of a Microchannel Aeration Cathode for Producing H2O2 via Oxygen Reduction Reaction.

Electrochemical oxygen reduction is a promising method for in situ H2O2 production. Its important precondition is that dissolved oxygen molecules have to diffuse to and arrive at the cathode surface for reacting with electrons. Obviously, shortening the diffusion distance is beneficial to improve the reaction efficiency. In this study, a novel microchannel aeration mode was proposed to confine the diffusion distance of O2 to the micrometer level. For this mode, an aeration cathode was fabricated from a carbon block with microchannel arrays. The diameter of each channel was only 10-40 μm. Oxygen will be pumped into every microchannel from the top entry, while an aqueous solution will permeate into microchannels through the bottom entry and pores in the channel wall. This microchannel aeration cathode exhibited a H2O2 yield of up to 4.34 mg h-1 cm-2, about eight times higher than that of the common bubbling aeration mode. The corresponding energy consumption was only 7.35 kWh kg-1, which was superior to most reported results. In addition to H2O2, this aeration cathode may also produce •OH via a one-electron reduction of H2O2. In combination with H2O2 and •OH, phenol, sulfamethoxazole, and atrazine were degraded effectively. We expect that this microchannel aeration cathode may inspire researchers focused on H2O2 production, water pollutant control, and other multiphase interfacial reactions.

COMPARATIVE CFD BASED PARAMETRIC ANALYSIS OF GAS FLOW IN TWO CONTER-FLOW WET SCRUBBER SYSTEMS

" In this study, gas flow field were simulated using ANSYS 2020R2, Fluid Flow Fluent computational fluids dynamic (CFD) software based on the continuity, velocity, temperature, energy and k -  turbulence. The overall objective of the study is to compare the pressure and velocity maps inside the wet scrubber system for two different scrubber designs. I have choose to analyse an In-Line scrubber bottom inlet, type I, and In-Line scrubber side inlet, type L. Bottom entry or side entry designs to allow a direct up-flow configuration and simplify engine exhaust gas duct routing for any type of vessel. The flow in a wet scrubber is very complex due to the interaction between dust particles, water droplets, and bulk water and flue gas. The flue gas flow is turbulent and there are multiple phases (gas, liquid and solid). CFD codes that predict gas flow patterns are based on conservation equations for mass, momentum and energy. The results show that the residuals have a very good job of converging at minimum flow contours and vectors at the inlet across the scrubbing chamber and outlet shows a distributed flow. The velocity profiles have fully conformed to the recommended profile for turbulent flow in pipes. As can be seen in the figures above, the velocity flow contour inside the scrubber is higher in the scrubber side inlet. Even though I choose to study the simplified scrubber model without taking into account that spray nozzle improve mixing between the scrubbing liquid and waste gas; from the results obtained, it can be deduced that the numerical simulation using CFD is an effective method to study the flow characteristics of a counter-flow wet scrubber system. "

Structural analysis of ancient Chinese wooden locks

Humans all around the world have used locks for thousands of years. Wooden locks were the earliest locks in ancient China and were firmly fixed to the door. There are two principal types: bolt locks and pin tumbler locks. The original bolt lock was made with a thick bolt and the door. It could only be opened from the inside of the door. Improved continuously, a large number of wooden locks with different structures were invented. This work presents a systematic analysis of the structures of ancient Chinese wooden locks. The characteristics and the representations of wooden locks are described. There are totally 10 types of wooden locks that are presented as examples to demonstrate the operation processes. According to the insertion position of the key, Chinese wooden locks can be divided into seven types: no entry, bolt entry, case side entry, case bottom entry, case top entry, case front entry, and multiple entries. Ancient Chinese wooden locks come in various types with different ingenious designs, fully demonstrating the work of the highly skilled artisans in ancient Chinese society.

Addressing huge spatial heterogeneity induced by virus infections in lentil breeding trials.

BackgroundSpatial heterogeneity can have serious effects on the precision of field experimentation in plant breeding. In the present study the capacity of the honeycomb design (HD) to sample huge spatial heterogeneity was appraised. For this purpose, four trials were conducted each comprising a lentil landrace being screened for response to viruses.ResultsHuge spatial heterogeneity was reflected by the abnormally high values for coefficient of variation (CV) of single-plant yields, ranging 123–162 %. At a given field area, increasing the number of simulated entries was followed by declined effectiveness of the method, on account of the larger circular block implying greater intra-block heterogeneity; a hyperbolic increasing pattern of the top to bottom entry mean gap (TBG) indicated that a number of more than 100 replicates (number of plants per entry) is the crucial threshold to avoid significant deterioration of the sampling degree. Nevertheless, the honeycomb model kept dealing with variation better than the randomized complete block (RCB) pattern, thanks to the circular shape and standardized type of block that ensure the less possible extra heterogeneity with expanding the area of the block.ConclusionsOwing to the even and systematic entry allocation, breeders do not need to be concerned with the extra spatial heterogeneity that might induce the extra surface needed to expand the size of the block when many entries are considered. Instead, they could improve accuracy of comparisons with increasing the number of replicates (circular blocks) despite the concomitant greater overall spatial heterogeneity.

Effect of Vortex Orifice Air Distributor on Granule Growth in Conical Fluidized Bed Granulation with Bottom Entry Spray.

This investigation is undertaken to obtain information on the effect of vortex orifice air distributors on the granule growth in conical fluidized bed granulation with a bottom entry spray. The five types of vortex orifice distributors suitable for a strong swirling air supply at the base of the conical bed were prepared. Although all these orifices consisted of four tangential injection nozzles with the same opening, the opening size of the air injection nozzle in each of the orifices was different. Intensity of the air injection nozzle torque within the vortex orifice was measured by a torque balance method. The granule formation of fluidizing lactose particles in the process of size-enlargement was carried out by spraying an aqueous HPC (hydroxypropyl cellulose) solution into the bed where the moisture content of granules was maintained at or below 0.30 wt%. As a result, granule growth in the bed could be precisely controlled by changes in the air injection nozzle torques arising from the vortex orifice distributor. The extent of granule growth, namely the granule growth conversion increasing with accumulated content of HPC in the bed particles during the operating time decreased according to the air injection nozzle torque within the vortex orifice. Using these process variables, granule growth conversion could be arranged experimentally. It is finally found that one of the features of the proposed air distributor is useful for size-control of granule products in the conical fluidized bed granulation with a bottom entry spray.

Mantle heat exchangers for horizontal tank thermosyphon solar water heaters

This paper describes the characteristics of horizontal mantle heat exchangers for application in thermosyphon solar water heaters. A new correlation for heat transfer in horizontal mantle heat exchangers with bottom entry and exit ports was used to predict the overall heat transfer and stratification conditions in horizontal tanks with mantle heat exchangers. The model of a mantle heat exchanger tank was combined with the thermosyphon solar collector loop model in TRNSYS to develop a model of a thermosyphon solar water heater with collector loop heat exchanger. Predictions of stratification conditions in a horizontal mantle tank are compared with transient charging tests in a laboratory test rig. Predictions of daily energy gain in solar preheaters and in systems with in-tank auxiliary boosters are compared with extensive outdoor measurements and the model is found to give reliable results for both daily and long-term performance analysis.

Equipment

EKATO, specialists in mixing technology, have developed single and double acting mechanical seals with silicon carbide rings specifically designed for installation in bottom entry agitators as a protection against crystallising and abrasive suspensions.

Inherent Safety in the Design of Future Nuclear Plants

By making public health and safety a primary criterion in the initial conceptual design, future nuclear power plants could be made inherently safe to the point where they could be legitimately sited nearly anywhere instead of only in the most remote locations. It is found that an unpressurized, ''pool-type'', sodium-cooled reactor, which would be controlled by the movement of bottom entry fuel assemblies, would allow a heavy shielding dome to be permanently installed directly over the reactor. This would allow on-line refueling and the continuous removal of the free gaseous fission products from the reactor to a naturally cooled, well-protected site. It would also allow high-temperature decay heat to be transported directly to the ever present atmosphere by a system that is simple enough to preclude fuel melting in a shutdown reactor. 13 refs.

An analysis of bottom entry nozzles for atmospheric storage tanks

In this paper, we describe the analysis of soil settlement in the vicinity of a bottom entry nozzle of an atmospheric storage tank for several practical loadings. These are the pressure of the liquid stored in the tank, the body force of the rock and soil foundation, and an external moment applied to the nozzle where it emerges from the foundation. The foundation is modelled as a three-dimensional elastic medium which can support no tensile stress and is composed of two materials (rock and soil) with an elastic cylindrical shell embedded in the rock phase. The solution is accomplished with a general-purpose finite element program (ICES—STRUDL II). The overall conclusion reached is that bottom entry nozzles are acceptable for tankage installed on reasonably good soil.

Corrigendum

‘MHD Rankine-Hugoniot equations applied to earth's bow shock’by J. D. Mihalov, C. P. Sonett and J. H. WolfeJ. Plasma Physics (1969), vol. 3, part 3, pp. 449–463The bottom entry of column 2, Table 2, page 455, should read ‘–20’ instead of ‘20’. Recent work suggests the possibility of a systematic error as large as ˜ –3 deg in ø(‘spacecraft’ co-ordinates) of Table 1, page 453. The calculations have been repeated with the ø values decreased by 2·8 deg, with the result that none of the conclusions of the paper are changed since the detailed numerical results are not significantly different.On page 463, the fifteenth of the list of references should read:Ness, N. F. & Taylor, H. E. 1969 Annals of the IQSY, 3, 366.On the same page, the fifth to the last of the list of references should read:Wilcox, J. M. 1969 Solar Flares and Space Research, p. 294 (edited by C. de Jager and Z. Švestka). Amsterdam: North-Holland Publishing Co.