Degradation of a Jet A Fuel in a Single-Pass Heat Exchanger

1995 ◽  
Vol 117 (1) ◽  
pp. 125-131 ◽  
Author(s):  
E. G. Jones ◽  
W. J. Balster ◽  
M. E. Post
Keyword(s):  
Room Temperature ◽  
Oxygen Depletion ◽  
Low Flow ◽  
Fuel Temperature ◽  
Steel Tubes ◽  
Surface Deposition ◽  
Single Pass ◽  
Isothermal Conditions ◽  
Series Of Experiments ◽  
Pass Through

The formation of bulk and surface insolubles in a Jet A fuel during a single pass through heated stainless-steel tubes has been studied. Low temperature and low flow rates were utilized to produce near-isothermal conditions. In a second series of experiments, depletion of oxygen in the fuel saturated with respect to room-temperature air was measured under identical isothermal conditions. At a wall/bulk-fuel temperature of 185°C, rates of surface deposition and oxygen depletion were correlated; the maximum in the surface-deposition rate was found to occur after the Jet A fuel was stressed sufficiently that the dissolved oxygen was totally consumed. Results are discussed in terms of the autoxidation of the Jet A fuel and the concurrent production of deleterious bulk and surface insolubles.

Degradation of a Jet-A Fuel in a Single-Pass Heat Exchanger

1993 ◽  
Author(s):  
E. Grant Jones ◽  
Walter J. Balster ◽  
Michael E. Post
Keyword(s):  
Room Temperature ◽  
Oxygen Depletion ◽  
Low Flow ◽  
Fuel Temperature ◽  
Steel Tubes ◽  
Surface Deposition ◽  
Single Pass ◽  
Isothermal Conditions ◽  
Series Of Experiments ◽  
Pass Through

The formation of bulk and surface insolubles in a Jet-A fuel during a single pass through heated stainless-steel tubes has been studied. Low temperature and low flow rates were utilized to produce near-isothermal conditions. In a second series of experiments, depletion of oxygen in the fuel saturated with respect to room-temperature air was measured under identical isothermal conditions. At a wall/bulk-fuel temperature of 185°C, rates of surface deposition and oxygen depletion were correlated; the maximum in the surface-deposition rate was found to occur after the Jet-A fuel was stressed sufficiently that the dissolved oxygen was totally consumed. Results are discussed in terms of the autoxidation of the Jet-A fuel and the concurrent production of deleterious bulk and surface insolubles.

Shear stress induces eNOS mRNA expression and improves endothelium-dependent dilation in senescent soleus muscle feed arteries

2005 ◽  
Vol 98 (3) ◽  
pp. 940-946 ◽  
Author(s):  
Christopher R. Woodman ◽  
Elmer M. Price ◽  
M. Harold Laughlin
Keyword(s):  
Shear Stress ◽  
Mrna Expression ◽  
Soleus Muscle ◽  
Low Flow ◽  
No Production ◽  
Fischer 344 ◽  
Enos Mrna ◽  
Series Of Experiments ◽  
Endothelial Nitric Oxide ◽  
Feed Arteries

We tested the hypothesis that increased intraluminal shear stress induces endothelial nitric oxide (NO) synthase (eNOS) mRNA expression and improves endothelium-dependent dilation in senescent soleus muscle feed arteries (SFA) by increasing NO production. SFA were isolated from young (4 mo) and old (24 mo) male Fischer 344 rats and cannulated with two resistance-matched glass micropipettes. SFA were exposed to no flow (NF), low flow (LF), intermediate flow (IF), or high flow (HF) for 4 h. Mean intraluminal shear stress ranged from 0 to 82 dyn/cm2. At the end of the 4-h treatment period, eNOS mRNA expression was assessed in each SFA. eNOS mRNA expression was significantly lower in old NF SFA than in young NF SFA. In old SFA, eNOS mRNA expression was induced by IF (+154%) and HF (+136%), resulting in a level of expression that was not different from that of young SFA. In a separate series of experiments, SFA were pretreated with NF or HF for 4 h, and endothelial function was assessed by examining vasodilator responses to ACh. ACh-induced dilation was less in old NF SFA than young NF SFA. Pretreatment with HF improved ACh-induced dilation in old SFA such that the response was similar to that of young SFA. In the presence of Nω-nitro-l-arginine to inhibit NOS, ACh-induced dilation was inhibited in old HF SFA such that the response was no longer greater than that of old NF SFA. These results indicate that increased intraluminal shear stress induces eNOS mRNA expression and improves endothelium-dependent dilation in senescent SFA by increasing NO production.

Leukocyte kinetics in the human lung: role of exercise and catecholamines

1984 ◽  
Vol 57 (3) ◽  
pp. 711-719 ◽  
Author(s):  
A. L. Muir ◽  
M. Cruz ◽  
B. A. Martin ◽  
H. Thommasen ◽  
A. Belzberg ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Peripheral Blood ◽  
Human Lung ◽  
Work Load ◽  
Low Flow ◽  
Epinephrine Infusion ◽  
First Pass ◽  
Pass Through

In six normal supine subjects epinephrine infusion produced a greater leukocytosis with smaller changes in heart rate and blood pressure than did norepinephrine or isoproterenol. Upright exercise in those subjects produced a greater leukocytosis than supine exercise at the same work load. To determine the lung's participation in these events, indium-labeled neutrophils (PMN) were given to four of the subjects. We found that 20–25% were retained in the first pass through the lung when compared with technetium-labeled erythrocytes. The number of labeled PMN in the lung gradually decreased and the number in the spleen and the liver increased. Exercise and catecholamine infusion caused an acceleration in the release of labeled cells from the lung, an increase in both labeled and unlabeled cells in the peripheral blood, and an increase in the number of labeled cells in the liver and spleen. This suggests that increased perfusion of low-flow areas in the lung may contribute to the increased leukocytosis seen in association with both exercise and catecholamine infusion.

greater the probability that the particles will miss the high shear zones on a single pass through the device. For this reason the discharge of many rotor/stator devices is re-stricted with a series of holes or bars, or with a grid, which performs two separate tasks. First, a discharge grid absolutely limits the maximum particle size that can exit the mixer. If the holes on the discharge grid are 2 mm, it is virtually impossible for par-ticles larger than that diameter to pass through the machine. Rotor/stator in-line mix-ers are made with restricting grids as small as 0.5 mm, and a wide range of larger sizes up to 50 mm or even unrestricted outlets. A sample of such grids is presented in Fig. 29. But even the smallest usable discharge grid does not necessarily provide abso-lute control of the required size distributions in the range of fine dispersion. This is the second reason for the restriction on the discharge. By putting a more limiting dis-charge on the outlet, the flow rate through the device for a given set of pumping cir-cumstances (viscosity, density, system suction, and discharge head) is reduced and the residence time in the machine for a given particle or droplet is increased. The longer residence time increases the probability that a particle has to travel through the highest shearing zones and, thereby, be reduced to the smallest size that the machine is capable of producing. • • • • " ' ; • " * * «L £ J- •-

1998 ◽  
pp. 358-360
Keyword(s):  
Particle Size ◽  
Residence Time ◽  
Flow Rate ◽  
Shear Zones ◽  
High Shear ◽  
Single Pass ◽  
Fine Dispersion ◽  
Wide Range ◽  
Maximum Particle ◽  
Pass Through

Green Generation by Single-Pass Frequency-Doubling in a Periodically Poled MgO:LiNbO3 at Room Temperature

2012 ◽  
Vol 622-623 ◽  
pp. 1258-1261
Author(s):  
Hong Bo An ◽  
Bing Hua Su ◽  
Li Hong Niu ◽  
Jun Wen Xue
Keyword(s):  
Room Temperature ◽  
Continuous Wave ◽  
Second Harmonic ◽  
Frequency Doubling ◽  
Green Emission ◽  
Simulation Data ◽  
Periodically Poled ◽  
Single Pass ◽  
Narrow Bandwidth ◽  
Rayleigh Length

122mW green emission at 532.3nm with a conversion efficiency of 1.2% was measured by single-pass second-harmonic generation in a 10mm long periodically poled MgO:LiNbO3 (MgO:PPLN) crystal is reported. A continuous-wave Yb-doped fiber laser operating at 1064.6nm with narrow bandwidth of 0.1nm is used as pumping source. The experimental temperature acceptance bandwidth ΔT=4.6°C is a little higher than the simulation data of 4°C. Output power instabilities or variations of the green beam pattern were not observed during experiments. In this work, the optimized efficiency was achieved when the waist located at the center of MgO:PPLN and Rayleigh length equal to its length, and the lens’ location in the system was calculated.

Surface Deposition Characteristics on Long Thermal Duration Within Treated and Untreated Stain Steel Tubes of Supercritical Kerosene RP-3 Fuel

2021 ◽  
pp. 257-270
Author(s):  
Kun Zhu ◽  
Xiao Yu ◽  
Guoqiang Xu ◽  
Jiankun Li ◽  
Chunlei Zhang ◽  
...  
Keyword(s):  
Steel Tubes ◽  
Surface Deposition

Flow dependence of norepinephrine extraction by isolated perfused rat lungs

1982 ◽  
Vol 242 (5) ◽  
pp. H844-H848
Author(s):  
R. A. Roth
Keyword(s):  
Extraction Ratio ◽  
Low Flow ◽  
Pulmonary Vasculature ◽  
Rat Lung ◽  
Perfusion Medium ◽  
Normal Organ ◽  
Flow Dependence ◽  
Rat Lungs ◽  
Pass Through

Disposition of perfused norepinephrine (NE) was studied in isolated rat lungs at several perfusate flows, including that occurring in vivo. Lungs were ventilated with 95% O2-5% CO2 and perfused at 37 degrees C with recirculating medium initially containing 90 nM [14C]NE. In agreement with previous studies the fraction of NE removed in a single pass through the pulmonary vasculature was 0.30 +/- 0.03 by lungs perfused at low flow (10 ml/min; 7.2 ml.min-1.g lung-1). This extraction ratio decreased with increasing flow, so that in lungs perfused at 45 ml/min (31.8 ml.min-1.g lung-1) the extraction ratio was 0.09 +/- 0.01. The concentration of NE metabolites in the perfusate reservoir increased with time of perfusion. The rate of appearance of deaminated and O-methylated metabolites in the recirculating perfusion medium was not markedly influenced by flow. NE that accumulated in lung was metabolized before reentry into the perfusion medium. These results indicate that extraction of NE by rat lung is markedly dependent on flow and suggest that removal of NE by lung is not highly efficient at normal organ perfusion rates.

An Improved Approach to Audio Segmentation and Classification in Broadcasting Industries

2019 ◽  
Vol 30 (2) ◽  
pp. 44-66
Author(s):  
Jingzhou Sun ◽  
Yongbin Wang
Keyword(s):  
Audio Segmentation ◽  
Audio Processing ◽  
Network Method ◽  
Audio Data ◽  
Series Of Experiments ◽  
Pass Through ◽  
Short Time ◽  
Fully Connected ◽  
Alternative Solutions ◽  
Audio Segmentation And Classification

Audio segmentation and classification are the basis of audio processing in broadcasting industries. A Dual-CNN (Dual-Convolutional Neural Network) method is proposed in this article in which it is possible to pre-train a CNN with unlabeled audio data so as to deal with the scarcity of labeled data. Auto-encoders (including an encoder and a decoder) are utilized, thus the name “Dual.” In the first place, audio sampling points and the derived STFT (Short-Time Fourier Transform) spectrograms pass through their own CNNs. Fusion of the extracted features is then performed. Finally, the merged features are sent to a fully connected network and the classification results are produced via Softmax. Being one of the segmentation-by-classification approaches, our solution also presents a novel smoothing method (SEG-smoothing) in order to deliver the best result of segmentation. A series of experiments have been conducted and their result verifies that the proposed approach for segmentation and classification outperforms alternative solutions.

Stable sample delivery in viscous media via a capillary for serial crystallography

2020 ◽  
Vol 53 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Ki Hyun Nam
Keyword(s):  
Room Temperature ◽  
Capillary Tube ◽  
Glucose Isomerase ◽  
Low Flow ◽  
Innovative Technology ◽  
Delivery Method ◽  
Crystal Sample ◽  
X Ray ◽  
Serial Crystallography ◽  
Delivery Medium

Serial crystallography (SX) is an innovative technology in structural biology that enables the visualization of the molecular dynamics of macromolecules at room temperature. SX experiments always require a considerable amount of effort to deliver a crystal sample to the X-ray interaction point continuously and reliably. Here, a sample-delivery method using a capillary and a delivery medium is introduced. The crystals embedded in the delivery medium can pass through the capillary tube, which is aligned with the X-ray beam, at very low flow rates without requiring elaborate delivery techniques, drastically reducing sample consumption. In serial millisecond crystallography using a viscous medium via a capillary, crystals of lysozyme embedded in agarose, which produce an unstable injection stream at atmospheric pressure, and crystals of glucose isomerase embedded in gelatin, which is known to be problematic for open-extruder operation, were stably delivered at a flow rate of 100 nl min−1. The room-temperature crystal structures of lysozyme and glucose isomerase were successfully determined at 1.85 and 1.70 Å resolutions, respectively. This simple but highly efficient sample-delivery method can allow researchers to deliver crystals precisely to an X-ray beam in SX experiments.

Sign in / Sign up

Export Citation Format

Share Document