Sapphire probe laser ablation of human arteries with CO2 gas and saline perfusion: The effect of flow rate, lasing power and lasing time

1992 ◽  
Vol 7 (1-4) ◽  
pp. 55-62
Author(s):  
Xiaoming Yang ◽  
Hannu Manninen ◽  
Anita Naukkarinen ◽  
Hongxiu Ji ◽  
Seppo Soimakallio
Keyword(s):  
Laser Ablation ◽  
Flow Rate ◽  
Probe Laser ◽  
Co2 Gas ◽  
Lasing Power ◽  
Human Arteries

CO2 Gas Perfusion: Improved Efficiency and Safety with Sapphire-Probe Laser Ablation of Human Artery

1991 ◽  
Vol 2 (1) ◽  
pp. 159-165
Author(s):  
Xiaoming Yang ◽  
Hannu Manninen ◽  
Anita Naukkarinen ◽  
Hongxiu Ji ◽  
Jussi P. Kankkunen ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Probe Laser ◽  
Human Artery ◽  
Co2 Gas

scholarly journals TOTAL VOLUMETRIC MASS TRANSFER COEFFICIENT AT CO2 GAS ABSORPTION USING K2CO3 BY MSG PROMOTER

Konversi ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Erlinda Ningsih ◽  
Abas Sato ◽  
Mochammad Alfan Nafiuddin ◽  
Wisnu Setyo Putranto
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Liquid Flow ◽  
Total Mass ◽  
Gas Flow ◽  
Liquid Flow Rate ◽  
Gas Flow Rate ◽  
Co2 Gas

Abstract- One of the most widely used processes for CO2 gas removal is Absorption. Carbon dioxide is the result of the fuel combustion process which of the hazardous gases. The aim of this research is to determine the total mass transfer coefficient and analyze the effect of the absorbent flow rate of the absorbent solution with the promoter and the gas flow rate to the total mass transfer coefficient value. The variables consisted of liquid flow rate: 1, 2, 3, 4, 5 liter/min, gas flow rate: 15, 25, 30, 40, 50 liter/min and MSG concentration: 0%, 1%, 3% and 5% by weight. The solution of Pottasium Carbonate as absorbent with MSG promoter is flowed through top column and CO2 gas flowed from bottom packed column. Liquids were analyzed by titration and the gas output was analyzed by GC. From this research, it is found that the flow rate of gas and the liquid flow rate is directly proportional to the value of KGa. The liquid flow rate variable 5 liters / minute, gas flow rate 15 l / min obtained value of KGa 11,1102 at concentration of MSG 5%. Keywords:  Absorption, CO2,  K2CO3, MSG. 

Effects of Laser Ablation on Growth of ZnO/ZnS/ZnO Multilayer Structured Nanorods by Chemical Vapor Deposition

2008 ◽  
Vol 1144 ◽  
Author(s):  
Takashi Hirate ◽  
Hiroaki Koisikawa ◽  
Makoto Yugi ◽  
Takuya Kumada ◽  
Yuki Matsuzawa ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Laser Ablation ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Zno Nanorods ◽  
Chemical Vapor ◽  
The Other ◽  
The Third

ABSTRACTZnO is an attractive II-VI compound semiconductor material for various optoelectronic devices. Recently, growth of various nanostructures of ZnO such as nanorod, nanobelt, nanowall, etc. has been reported, and ZnO has been considered as a promising material for nanodevices. We have studied on fabrication of aligned ZnO nanorods by a low-pressure thermal chemical vapor deposition (CVD) method cooperated with laser ablation of Mn pellet. In this paper, we report on fabrication of ZnO/ZnS/ZnO multilayer structured nanorods and particularly on effects of laser ablation on the morphology of the nanorods intending to develop a new electroluminescent device including ZnO nanorods. The fabrication method of ZnO/ZnS/ZnO multilayer structured nanorods is almost same method used in our previous study. Metal Zn vapor and O2 gas or H2S are used as precursors to synthesize ZnO or ZnS, and N2 is used as carrier gas. A Mn pellet is placed near a Si(111) substrate in a deposition chamber and ablated by a pulsed Nd:YAG laser beam (wavelength =1.064 mm, pulse width = 8 ns, repetition frequency = 10 shots/sec). The pressure is 13.3 Pa and the temperature is 550 C. When ZnO is grown, O2 of 0.88 SCCM mass flow rate is used as a precursor. When ZnS is grown, on the other hand, H2S of 2.0 SCCM mass flow rate is used as a precursor. The growth time is 15 min for each layer. Firstly, ZnO nanorods are grown. Laser ablation of Mn is executed for initial 3 min and only CVD is performed for remaining 12 min. The vertically aligned ZnO nanorods with 100 nm diameter and 1500 nm height are grown. Secondly, ZnS nanorod is grown on the top surface of the first ZnO nanorods. In this process, the morphology is not so dependent on execution of laser ablation of Mn for initial 3 min in this growth process. Finally, ZnO layer is again grown on ZnS/ZnO nanorods described above. When the laser ablation of Mn for initial 3 min is not executed, many fine ZnO whiskers with long length are grown with random directions on the top surface and on the side surfaces of ZnS/ZnO nanorods. When the laser ablation of Mn for initial 3 min is executed, on the other side, a thick whisker is grown on top surface of ZnS/ZnO nanorods. The shape is not nanorod. The diameter is abruptly decreased and the tip is very sharp. The growth of ZnO whisker on the side surface of ZnS/ZnO nanorods is not almost observed. It is found that the laser ablation of Mn for initial 3 min in the third ZnO growth strongly influences the morphology of the third ZnO layer. We estimate that the Mn species that are ablated from a Mn pellet and reaches the surface of ZnS/ZnO nanorods change any quality of the surface of ZnS/ZnO nanorods. We are now studying of finding the growth conditions of the third ZnO layer with morphology of nanorod on ZnS/ZnO nanorods that is considered to be suitable for electroluminescent devices.

Excimer-laser-induced fluorescence spectroscopy of human arteries during laser ablation

1991 ◽  
Author(s):  
B. Abel ◽  
Horst Hippler ◽  
B. Koerber ◽  
Andreas J. Morguet ◽  
Walter Neu
Keyword(s):  
Laser Ablation ◽  
Fluorescence Spectroscopy ◽  
Excimer Laser ◽  
Laser Induced Fluorescence ◽  
Human Arteries

Effect of Temperature Gradient near the Target and Gas Flow Rate on the Diameter Distribution of Single-Walled Carbon Nanotubes Grown by the Laser Ablation Technique

2000 ◽  
Vol 633 ◽  
Author(s):  
Rahul Sen ◽  
Hiromichi Kataura ◽  
Yohsuke Ohtsuka ◽  
Toshinobu Ishigaki ◽  
Shinzo Suzuki ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Laser Ablation ◽  
Temperature Gradient ◽  
Flow Rate ◽  
Gas Flow ◽  
Single Walled Carbon Nanotubes ◽  
Diameter Distribution ◽  
Gas Flow Rate ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes

AbstractGas dynamic and time resolved imaging studies have been performed on the growth of single-walled carbon nanotubes (SWNTs) in the laser ablation process. SWNTs were synthesized by laser ablation of Ni-Co catalyzed graphite targets at 1200°C under argon flow. The effects of the temperature gradient near the target and the gas flow rate were studied in order to understand the effect of gas dynamics over the diameter distribution of SWNTs. The gas flow rate affects the diameter distribution of SWNTs especially when the growth species flow through a large temperature gradient. Scattering images from the growth species at different flow rates was recorded by high-speed video imaging. The results indicate that the velocities of these species are dependent on the gas flow rate but this dependence is evident 30 ms after the laser ablation. These findings are used to estimate the time period for the nucleation and the growth of SWNTs.

Design and Analysis of the Axial Bypass Compressor Blade of the Supercritical CO2 Gas Turbine

2009 ◽  
Author(s):  
Takao Ishizuka ◽  
Yasushi Muto ◽  
Masanori Aritomi ◽  
Nobuyoshi Tsuzuki ◽  
Hiroshige Kikura
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Inlet Pressure ◽  
Inlet Temperature ◽  
Pressure Side ◽  
Aerodynamic Design ◽  
Co2 Gas

A supercritical carbon dioxide (S-CO2) gas turbine can generate power at a high cycle thermal efficiency, even at a modest temperature level of 500–550°C. Its high thermal efficiency is attributed to markedly reduced compressor work at the vicinity of the critical point. Furthermore, the reaction between Na and CO2 is milder than that between H2O and Na. Consequently, a more reliable and economically advantageous power generation system is achieved by coupling with a Na cooled fast reactor. In a typical design, the reactor thermal power, a turbine inlet pressure and an inlet temperature are, respectively, 600 MW, 20 MPa and 527°C. In the S-CO2 gas turbine system, a partial cooling cycle is used to compensate a difference in heat capacity for the high-temperature – low-pressure side and the low-temperature – high-pressure side of the recuperators to achieve high cycle thermal efficiency. The flow is divided into two streams before the precooler. One stream goes to recuperator 2 via a main compressor (MC); the other goes to recuperator 1 via a bypass compressor (BC). The performance and integrity of these two compressors are crucial. As described herein, an aerodynamic design of BC is given. The inlet temperature, inlet pressure, exit pressure and mass flow rate are, respectively, 77°C, 8 MPa, 20 MPa and 1392 kg/s. The salient features of this compressor are its compact size and a large bending stress caused by the large mass flow rate. The number of stages is numerous associated with the large enthalpy rise compared with MC. To achieve as high efficiency as possible, not a centrifugal type but an axial type is examined first. The aerodynamic design was conducted using one-dimensional design method, where the loss model of Cohen et al. is used. Its aerodynamic design enables the use of several stages and provides total adiabatic efficiency of 21 and 87%, respectively. Then, CFD analysis was conducted using “FLUENT”. Blade shapes were prepared based on flow angles and chord length obtained in the aerodynamic design. The CO2 properties in a fluid computer dataset “PROPATH” were used. The features of gas velocity distribution and pressure distribution were confirmed to the fundamental knowledge. The value of the calculated flow rate coincided very well with that of the design.

scholarly journals Comparison of transient absorption of laser ablation plasma with fundamental plasma absorption relations

2021 ◽  
Vol 127 (7) ◽  
Author(s):  
Matthew Eliceiri ◽  
Costas P. Grigoropoulos
Keyword(s):  
Laser Ablation ◽  
Transient Absorption ◽  
Probe Laser ◽  
Linear Absorption ◽  
Time Resolved ◽  
Nanosecond Pulsed Laser ◽  
Ablation Plasma ◽  
Fluence Regime ◽  
Plasma Absorption

AbstractNanosecond pulsed laser ablation plasmas were studied by time resolved shadowgraphy coupled with normal imaging, followed by laser probing and plasma spectroscopy in the 5-25 J/cm2 fluence regime. We describe methods for imaging and probing that allow us to determine variations in the distribution of ejecta in the plume and monitor the optical absorption using a probe laser to obtain a measure of the linear absorption coefficient of the plasma. Experimental determination of absorber distribution also corresponds well to the theoretical prediction of density increase near the emitted shockwave edge. We finally demonstrate that fundamental plasma correlations can accurately describe the absorption of light by the plasma near the ablation wavelength. We observed good agreement in peak attenuation, directly measuring 65% peak absorption and compared to a calculation of 57% using a simple model of the plasma, but a 10 ns shift in peak attenuation time. The shift in dip times is explained both by experimental error and a fundamental imprecision in the model proposed for the expansion.

scholarly journals The effect of CO2 gas flow rate on precipitated CaCO3 formed at room temperature

2018 ◽  
Author(s):  
Fatimatul Munawaroh ◽  
Laila Khamsatul Muharrami ◽  
Triwikantoro ◽  
Zaenal Arifin
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Room Temperature ◽  
Gas Flow Rate ◽  
Co2 Gas
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