Energy and exergy analysis of a downstream single-row air washer at different droplet diameters for air cooling application

This study proposes a downstream single-row air washer for air cooling. The theoretical energy and exergy balance models were established at different droplet diameters and verified by the experimental data. Based on the abovementioned theoretical relationship, the single performance indicator of heat exchange efficiency (HEE) and exergy efficiency was quantitatively analyzed; a comprehensive analysis method of two indicators was proposed, combining HEE and exergy efficiency, and a numerical simulation was carried out. Results show that the smaller the droplet diameter and the larger the water–air ratio, the lower the dry-bulb temperature of the outlet air and the higher the HEE and exergy flux destruction. When the droplet diameter is less than 440 μm, the droplet diameter does not affect exergy efficiency and dry-bulb temperature. When the droplet diameter is larger than 440 μm, the droplet diameter is positively correlated with the air outlet dry-bulb temperature and exergy efficiency; in contrast, the water–gas ratio is negatively correlated with the air outlet dry-bulb temperature. An engineering case reveals that when the air outlet temperature is less than 34°C, the critical water–gas ratio can be set as 2.6 (mass ratio). At this time, the HEE is more than 90%, the exergy efficiency is more than 60%, and the critical value of droplet diameter is 440 μm. The research results provide an essential theoretical basis for the optimization of engineering design calculation.

DESIGN AND TEST EVALUATION OF THE SUBSOILER EQUIPPED WITH TILLAGE DEPTH MONITORING AND CONTROL SUBSOILING ASSEMBLIES

Aiming at solving problems that the variation of tillage depth between rows and within rows caused by the surface undulation was great, the lateral stability of tillage depth obtained by the method of adjusting at the three-point suspension was poor, and lack of subsoilers with the function of accurate detection and adjustment of single row tillage depth, a method of independent control of single row tillage depth based on ultrasonic sensor detection and hydraulic adjustment was proposed. And the tillage depth monitoring and control subsoiling assembly and the subsoiler equipped with subsoiling assemblies were designed. The key structural parameters of the hydraulic cylinder and the model of the three-position four-way magnetic exchange valve were determined. The subsoiling quality and performance comparison tests were conducted, and the results showed that the mean value of the variable coefficient of soil hardness, looseness of soil and coefficient of soil disturbance were 52.23%, 32.55% and 62.15%, respectively, and the stability coefficient of tillage depth was 92.43%, which all met the subsoiling operation requirements. The standard deviation of tillage depth belonged to the method of independent adjustment of single row and unified adjustment of each row were 38.315mm and 51.521mm, respectively. The subsoiler equipped with tillage depth monitoring and control subsoiling assemblies designed in this paper was capable of significantly improving the stability of tillage depth between rows and within rows.

Propeller Clock using Arduino Nano Micro-controller

Once John Lubbock rightfully propounded, “What we see depends mainly on what we look for”. Perfection is a just a illusion whereas Perception is the real vision. This “illusion” is based on inertia of human eye. Propeller clock is a special kind of circular LED display. It is making use of POV, a scientific phenomena termed as ‘Persistence of Vision’, which means that if something appears in the same spot consistently, at least 50-60 times per second, our brains think that it’s permanently there when it is not. The term ‘Persistence of Vision display’ or ‘POV display’ has been used for LED display devices that compose images by displaying one spatial portion at a time in rapid succession (for example, one column of pixels every few milliseconds). A two-dimensional POV display is often accomplished by means of rapidly moving a single row of LEDs along a linear or circular path. The effect is that the image is perceived as a whole by the viewer as long as the entire path is completed during the visual persistence time of the human eye. A further effect is often to give the illusion of the image floating in mid-air. This implementation will be a coordination of electrical, electronics and mechanical engineering. Keywords: Persistence of Vision, Arduino Nano, Micro-controller, Led’s, Propeller, POV

Efficient Covering of Thin Convex Domains Using Congruent Discs

We present efficient strategies for covering classes of thin domains in the plane using unit discs. We start with efficient covering of narrow domains using a single row of covering discs. We then move to efficient covering of general rectangles by discs centered at the lattice points of an irregular hexagonal lattice. This optimization uses a lattice that leads to a covering using a small number of discs. We compare the bounds on the covering using the presented strategies to the bounds obtained from the standard honeycomb covering, which is asymptotically optimal for fat domains, and show the improvement for thin domains.

Signaling on the railway transport of Russia. History of origin and development

The development of humanity is impossible without means of signaling. Signaling in any sphere of human activity has always been a means of ensuring the safety of his life. One of these areas was railway transport, the development of which and, accordingly, signalling facilities began in the early 19th century.With the progress of technological progress in Russia, signaling tools have also evolved, which have gone from the simplest sound and optical signals to modern ones using satellite technologies. Naturally, this path in the technical evolution of mankind is of interest to scientists and just curious people, since knowledge of the stages of the origin and development of signaling allows contemporaries to improve it and at the same time not forget the basics of this area.As a result of this process, the signaling system on railway transport, its means have undergone serious changes. Primitive ways of giving commands - optical (disk, flag) and sound (whistle) to the participants of the movement were pushed by more modern means of signaling, which already involve microprocessor technology and satellite technologies.An example of modern signaling means is the automatic locomotive signaling of a single row of continuous type (ALS-EN). The signal of this type of signaling is more informative: it contains information about the number of free block sections ahead of the train, as well as about the permissible speed of its movement.

Gypsum Supplies Calcium to Ultisol Soil and Its Effect on Pineapple Growth, Yield and Fruit Quality in Lower Single Bed under Climate Change Issue

A lower bed single row for pineapple cultivation could protect pineapple from soil erosion in rainy season and during drought, however, disease problem could arise due to water logging. Two experiments using a lower bed single row was done to understand the ability of gypsum providing soil calcium (Ca) available to pineapple plant, resistance to heart rot disease, and give better effect on crop growth and fruit quality of the pineapple in Ultisol soil. In the first trial, four level dosis of gypsum (0, 1.0, 1.5, 2.0 Mg ha-1) and dolomite 2 Mg ha-1 were applied by spreading and incorporated into the soil which have saturated with inoculums of Phytophthora nicotianae. In the second trial, gypsum treatments (0, 1.0, 1.5, 2.0, 2.5 Mg ha-1) were applied in the row between the single row beds as a basic fertilizer. The result showed that P. nicotianae attacked the pineapple plants in all treatments at 6 weeks after planting (WAP), and at 10 WAP, the mortality of dolomite treatment reached 63.8%, significantly different than that for gypsum treatments (3.3-14.3%). In the second experiment, gypsum increased plant weight significantly at 3 until 9 months after planting especially when it was applied 1.5-2.5 Mg ha-1. Fruit texture, total soluble solid (TSS), titratable acidity (TA) were not significant different among the treatment but all meet the standards for grades of canned pineapple. Result showed that soil applied gypsum before planting provides soil calcium and met the plant Ca requirement during a period of early and fast growth step and safe for heart rot disease.

The Contribution of Historical and Morphological Studies on Herbarium Specimens to a Better Definition of Chara pelosiana Avetta (Charales, Charophyceae)

The lectotype of Chara pelosiana Avetta 1898 was designated in 2000 by Langangen, who merged the species with Chara fibrosa Agardh ex Bruzelius. Chara pelosiana belongs to the section Agardhia Wood, but the true identity of the species has yet to be confirmed. The purpose of this work is to show some historical and morphological findings regarding this enigmatic species, on the basis of the analysis of herbarium specimens. The original material, which was studied by Avetta, is missing in Italian herbaria, but portions of it have been found in the Herbarium of Jena. Historical research on botanists related with this species resulted in the discovery of several specimens to be considered “original material”, and new unpublished localities in Northern Italy. Morphological observations have been made on portions of herbarium specimens as a contribution to unveil the taxonomic identity of this taxon. The specimens are diplostichous with ecorticate branchlets, have stipulodes in a single row, one or two per branchlet, and spine cell up to 1 mm long.