Amount Of Vacuum Research Articles

The effect of different variables and using of the internal adiabatic wall in the construction and performance of thermosiphon heat pipes: Experimental investigation

Heat pipes are a practical and powerful tool for recovering thermal energy and conserving energy sources. Thermosiphon is one of the most widely used devices that can transfer large amounts of heat at high rates between hot and cold sources without the use of external energy. The amount of vacuum in the pipe, the percentage of fluid filling, the type of operating fluid, the pipe’s length and the quantity of heat flux are the factors affecting the efficiency and effectiveness of the thermosiphon heat pipe. In this paper, the effects of different variables in the construction of heat pipes such as working fluid, pipe length, the use of mesh screen wick structure and the use of internal adiabatic wall on the thermosiphon heat pipes performance are investigated. The results show that using of an internal adiabatic wall eliminates and reduces limitations such as boiling, evaporator drying, thermosiphon flooding and vapor pressure and significantly improves the heat pipe’s performance. So that, the effective thermal conductivity (K) is increased up to 350% using the internal adiabatic wall. However, in some nanofluids, such as water/multi-walled carbon nanotubes (MWCNT), with increasing the nanofluid’s mass fraction, the startup speed in heat pipes with internal adiabatic wall is reduced by up to 20%.

Optimization of seed precision performance of a multi-rows pneumatic plate metering device using two seed ejecting methods

This study was conducted at College of Engineering, Huazhong Agricultural University, China, 2019. It aimed to inspect theinfluence of two devices on seed precision performance of a multi-rows pneumatic disk metering device. Curved-edge and positive air blower were the two devices specifically used at four plate velocities coupled with their well-matching vacuum levels. Seed distribution of the two methods was also verified at 15 and 20 r/min incorporated with 1.2 and 1.4 kPa vacuum pressure, and 0.9 and 1.0 kPa positive pressure, respectively. Results exposed that vacuum amount utilized with mentioned speeds were adequate for attaining closer rows pick-up with consistency CV not surpassed 2.84%. The lowest quality index attained was 89.88%, while miss index not exceeded 7.1%, and rows stability CV was below 1.15%. Curved-edge device was found to be superior to air blower in quality index, miss index and rows stability. Study results concluded the appropriateness of the devices methods for precise seeding with a little variance, and more precise devices set up may generate better results.

Design and experiment of multi-row pneumatic precision metering device for rapeseed.

The main objective of this study was to design a pneumatic disk with four-rows for planting rapeseed and to investigate its performance under several rotating speeds and vacuum pressure values. The effects of rotating speeds, vacuum pressure and rows on seed sucking and retaining were inspected. Six rotating speeds (5 r/min, 10 r/min, 15 r/min, 20 r/min, 25 r/min and 30 r/min) incorporated with the application of vacuum pressure were employed for detecting the optimum vacuum amount that was sufficient for seed sucking under each speed. These values of vacuum were found to be 1.1 kPa, 1.25 kPa, 1.35 kPa, 1.65 kPa, 1.8 kPa and 2.0 kPa, respectively. Moreover, a regression model was developed for predicting of vacuum pressure that corresponds with each rotating speed. Based on seed mass analysis, statistical differences were found at 5% significance under the influence of speeds and negative pressure and existed also between and within rows according to Duncan’s Test. The highest seed mass means of 3.17 g and 3.96 g were obtained by row 1 under the effects of speed and vacuum pressure, respectively, while the lowest means of 2.79 g and 3.05 g were attained by row 4. Due to the influence of rows, important differences were occurred between row 1 (closer to the center of rotation) and row 4 (farther one), particularly under high speeds (25 r/min and 30 r/min). Results concluded that, pneumatic disk with multiple-rows could be satisfactorily used for seed sowing with a little variation in seed amount between rows without any seed damage. The rows of hole farther from plate center of rotation were obviously influenced by angular velocity and vacuum amount rather than the closer ones. Keywords: precision seeder, metering device, performance, pneumatic, disk, multi-rows, rapeseed DOI: 10.25165/j.ijabe.20181105.3544 Citation: Ibrahim E J, Liao Q X, Wang L, Liao Y T, Yao L. Design and experiment of multi-row pneumatic precision metering device for rapeseed. Int J Agric & Biol Eng, 2018; 11(5): 116–123.

Efficacy of a Novel Narrow Knife with Water Jet Function for Colorectal Endoscopic Submucosal Dissection.

Backgrounds With respect to the knife's design in colorectal endoscopic submucosal dissection (ESD), diameter, water jet function, and electric power are important because these relate to efficient dissection. In this study, we analyzed a novel, narrow ball tip-typed ESD knife with water jet function (Flush knife BT-S, diameter: 2.2 mm, length: 2000 mm, Fujifilm Co., Tokyo, Japan) compared to a regular diameter knife (Flush knife BT, diameter: 2.6 mm, length: 1800 mm). Methods In laboratory and clinical research, electric power, knife insertion time, vacuum/suction amount with knife in the endoscopic channel, and water jet function were analyzed. We used a knife 2.0 mm long for BT-S and BT knives. Results The BT-S showed faster mean knife insertion time (sec) and better vacuum amount (ml/min) compared to the BT (insertion time: 16.7 versus 21.6, p < 0.001, vacuum amount: 38.0 versus 14.0, p < 0.01). Additionally, the water jet function of the BT-S was not inferior. In 39 colorectal ESD cases in two institutions, there were mean 4.7 times (range: 1–28) of knife insertion. Suction under knife happened 59% (23/39) and suction of fluid could be done in 100%. Conclusions Our study showed that the narrow knife allows significantly faster knife insertion, better vacuum function, and effective clinical results.

Development of Prediction Functions for a Maximized Precision Seeding Performance Based on Optimized Variables

&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &amp;nbsp;&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; The objective of this study was to develop&#x0D; prediction functions for the variables that affect precision seeding&#x0D; performance. The variables considered were the amount of vacuum, peripheral&#x0D; speed and the diameter of the holes on vacuum plate. On the other hand, these&#x0D; variables are significantly affected by physical properties of the seeds and&#x0D; govern the seeding phenomenon that is the capture, release and incorporation of&#x0D; seeds into the soil. Experiments using Central Composite Design which is one of&#x0D; the designs in Response Surface Methodology (RSM) were conducted in the lab and&#x0D; different seeds were used to meet the objective. Hence, using different seeds&#x0D; with different physical and aerodynamic properties such as sphericity, thousand&#x0D; seed mass, projected area, terminal velocity, mean particle diameter and&#x0D; coefficient of friction of material on metal are expected to contribute the&#x0D; development of prediction models for a maximized seeding performance.&amp;nbsp; According to results of the statistical&#x0D; analyses, hole diameter and vacuum pressure models were developed while no&#x0D; significant model was developed for the peripheral the speed of the vacuum&#x0D; plate. The appropriate hole diameter was found to be the function of mean&#x0D; particle diameter and sphericity with a coefficient of determination of 92.69%,&#x0D; while vacuum pressure was correlated to sphericity and terminal velocity (R2=76.74&#x0D; %). The developed models were verified by the use of different seeds and seed&#x0D; distribution was evaluated.

In-situ plasma processing to increase the accelerating gradients of superconducting radio-frequency cavities

A new in-situ plasma processing technique is being developed at the Spallation Neutron Source (SNS) to improve the performance of the cavities in operation. The technique utilizes a low-density reactive oxygen plasma at room temperature to remove top surface hydrocarbons. The plasma processing technique increases the work function of the cavity surface and reduces the overall amount of vacuum and electron activity during cavity operation; in particular it increases the field emission onset, which enables cavity operation at higher accelerating gradients. Experimental evidence also suggests that the SEY of the Nb surface decreases after plasma processing which helps mitigating multipacting issues. In this article, the main developments and results from the plasma processing R&D are presented and experimental results for in-situ plasma processing of dressed cavities in the SNS horizontal test apparatus are discussed.

The Effect of Different Amounts of Vacuum Applied During Sealing on Consumer Acceptance of Beef Gluteus Medius (Top Sirloin)

Samples of beef gluteus medius muscle (top sirloin) were sealed at three different levels of vacuum (minimal, medium, and high) and cooked sous vide to 56°C. There was no difference in cooking losses or juice pH due to the amount of vacuum applied during sealing. There were, however, significant differences in sensory properties as assessed by an 88-member consumer sensory panel. Applying vacuum increased the perception of juiciness, tenderness, beef flavor intensity, and liking of the beef compared with minimal vacuum. There were few differences between medium and high vacuum samples, though high vacuum samples had slightly more beef flavor intensity. Perception of juiciness was not correlated to retention of more juice, suggesting some other aspect of the vacuum sealing process affects this important parameter in beef gluteus medius muscle.

Luminescence spectroscopy of Eu(Bis-tris)3+ complexes in anhydrous DMF [Bis-tris = 2,2-bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol]: luminescence quenching rate constants for the 5D0 state of Eu3+ by DMF and polyalcoholic OH groups

Excitation and emission spectra and luminescence lifetimes of Eu3+ complexes obtained by dissolving anhydrous EuCl3 and EuCl3/2,2-bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol (Bis-tris) in anhydrous dimethylformamide (DMF) and those from a Eu(Bis-tris)2Cl3 crystalline sample have been studied. Two distinct Eu3+ complexes were observed when anhydrous EuCl3 was dissolved in anhydrous DMF, and one was interpreted as an outer-sphere complex of Cl− anion. Dissolution of an excess amount of vacuum dried NaClO4 or KPF6 in anhydrous DMF resulted in longer luminescence lifetimes, presumably reducing the effects of trace amounts of water in the solvent due to competitive binding of the water in the solvent by alkali metal cations. The quenching rate constant for the 5D0 state of Eu3+ ion by each complexed DMF molecule in solution and by each OH group in the Bis-tris from the Eu(Bis-tris)2Cl3 crystalline sample were 54 ± 1 and 495 ± 5 s−1, respectively, and these were used to interpret the plausible structures of the different Eu3+ complexes in the EuCl3/Bis-tris/DMF solution.

An Integrated System for Treating Nitrogen Supersaturated Water

Abstract Groundwater is commonly supersaturated with nitrogen and must be treated before it is used for culturing fish–especially sensitive species such as lake trout (Salvelinus namaycush) and Atlantic salmon (Salmo salar). We treated water with an integrated system that passed water through a packed column aerator, then through a vacuum degasser, and finally through another packed column aerator (installed as a backup system). Packed-column aeration prior to vacuum degassing provided increased efficiency because only a small amount of vacuum was required to remove the remaining excess nitrogen, and oxygen levels were not affected by the vacuum degasser. In well water passed through packed columns, nitrogen gas was reduced from 131 to 105% of saturation and oxygen was increased from 23 to 86% of saturation. With a vacuum pressure of 3 in Hg, the degasser further reduced the nitrogen gas from 105 to 99% of saturation, and oxygen saturation remained near 86%. The integrated system provided water in which a...

DETERMINING TUBING LENGTHS AND SOLUTION VELOCITIES IN VACUUM FARM MILK TRANSFER SYSTEMS

SummaryA formula and graphs are presented showing the relationship between pipe or tubing size and length, amount of vacuum and the rate of solution flow in the cleaning-in-place (CIP) of vacuum milk transfer systems.

RESEARCHES IN DRY-PRESS REFRACTORIES, III. THE EFFECT OF VACUUM ON THE UNFIRED PROPERTIES OF SOME DRY-PRESS REFRACTORY BATCHES1

A series of tests on several typical refractory bodies are presented. These include data showing the effect of varying the amount of vacuum, and its length of time of application on the green and dry properties. The limits of pressure attainable with a mechanical press are also discussed.