THE HPLC SEPARATION OF TWO MIXTURES OF NEUTRAL PESTICIDES: EFFECTS OF TEMPERATURE, GRADIENT STEEPNESS, AND FLOW RATE

2001 ◽  
Vol 24 (4) ◽  
pp. 543-553 ◽  
Author(s):  
A. Kotrikla ◽  
T. D. Lekkas
Keyword(s):  
Temperature Gradient ◽  
Flow Rate ◽  
Hplc Separation ◽  
Effects Of Temperature

EFFECTS OF TEMPERATURE GRADIENT ON LAMELLAR ORIENTATIONS OF DIRECTIONAL SOLIDIFIED TiAl--BASED ALLOY

2011 ◽  
Vol 46 (10) ◽  
pp. 1223-1229 ◽  
Author(s):  
Zhixia XIAO ◽  
Lijing ZHENG ◽  
Lili YANG ◽  
Jie YAN ◽  
Hu ZHANG
Keyword(s):  
Temperature Gradient ◽  
Effects Of Temperature

From thin films to shaped platelets: effects of temperature gradient on SnS synthesis

2020 ◽  
pp. 138507
Author(s):  
Thiago Carvalho ◽  
Myriano H. Oliveira ◽  
R. Magalhães-Paniago ◽  
Andre Santarosa Ferlauto
Keyword(s):  
Thin Films ◽  
Temperature Gradient ◽  
Effects Of Temperature

scholarly journals Temperature log simulations in high-enthalpy boreholes

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Jia Wang ◽  
Fabian Nitschke ◽  
Maziar Gholami Korzani ◽  
Thomas Kohl
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Temperature Gradient ◽  
Flow Rate ◽  
Fluid Loss ◽  
Flow Conditions ◽  
Flow Rates ◽  
High Enthalpy ◽  
Fluid Losses ◽  
Lateral Heat

Abstract Temperature logs have important applications in the geothermal industry such as the estimation of the static formation temperature (SFT) and the characterization of fluid loss from a borehole. However, the temperature distribution of the wellbore relies on various factors such as wellbore flow conditions, fluid losses, well layout, heat transfer mechanics within the fluid as well as between the wellbore and the surrounding rock formation, etc. In this context, the numerical approach presented in this paper is applied to investigate the influencing parameters/uncertainties in the interpretation of borehole logging data. To this end, synthetic temperature logs representing different well operation conditions were numerically generated using our newly developed wellbore simulator. Our models account for several complex operation scenarios resulting from the requirements of high-enthalpy wells where different flow conditions, such as mud injection with- and without fluid loss and shut-in, occur in the drill string and the annulus. The simulation results reveal that free convective heat transfer plays an important role in the earlier evolution of the shut-in-time temperature; high accuracy SFT estimation is only possible when long-term shut-in measurements are used. Two other simulation scenarios for a well under injection conditions show that applying simple temperature correction methods on the non-shut-in temperature data could lead to large errors for SFT estimation even at very low injection flow rates. Furthermore, the magnitude of the temperature gradient increase depends on the flow rate, the percentage of fluid loss and the lateral heat transfer between the fluid and the rock formation. As indicated by this study, under low fluid losses (< 30%) or relatively higher flow rates (> 20 L/s), the impact of flow rate and the lateral heat transfer on the temperature gradient increase can be ignored. These results provide insights on the key factors influencing the well temperature distribution, which are important for the choice of the drilling data to estimate SFT and the design of the inverse modeling scheme in future studies to determine an accurate SFT profile for the high-enthalpy geothermal environment.

Thermo-Fluid Design Simulation of Nd3+ POCl3 Transverse Flow Liquid Laser Cavity

2021 ◽  
pp. 1-31
Author(s):  
Vinod Singh ◽  
Gaurav Singhal ◽  
Prabal Talukdar
Keyword(s):  
Refractive Index ◽  
Temperature Gradient ◽  
Flow Rate ◽  
Optical Pumping ◽  
Gain Medium ◽  
Optical Path Difference ◽  
Path Difference ◽  
Transverse Flow ◽  
Optical Path ◽  
Liquid Laser

Abstract CFD based thermal design of a transverse flow optical cavity is carried out for 1 kW Nd3+ POCl3 liquid laser source to investigate temperature and velocity distribution in the optical pumping region of the cavity. Temperature gradient and turbulence both affect the refractive index of the liquid gain medium, which results in optical path difference, divergence and hence, poorer quality of the laser beam. The main purpose of this design is to achieve uniform flow and least temperature gradient in the optical pumping region so that the optical path difference can be minimized and a good beam quality can be achieved. CFD model has been developed for carrying out thermo-fluid simulations for this thermal system and based on these simulations, an optimum geometry of inlet ports along with their position from optical pumping region have been proposed. A user defined function (UDF) is incorporated for the input of spatially varying heat source term in each cell of the optical pumping region of the cavity. Variations in refractive index and optical path difference are estimated from the temperature data using another UDF. Simulation reveals that mass flow rate between 1.5 kg/s to 2.0 kg/s maintains the optical homogeneity of gain medium. Preliminary experiments have been carried out to demonstrate the effect of flow rate on the beam divergence and thereby exhibiting the importance of present simulation work.

Effects of temperature gradient reduction: Comparison of Drägersorb 800 Plus®, Drägersorb Free® and Amsorb Plus®

2008 ◽  
Vol 25 (Sup 44) ◽  
pp. 31
Author(s):  
G. Hirabayashi ◽  
H. Uchino ◽  
T. Nakajima ◽  
A. Kitagawa ◽  
N. Ishii
Keyword(s):  
Temperature Gradient ◽  
Effects Of Temperature

scholarly journals Development of a New HPLC Method for the Simultaneous Determination of Ticarcillin and Clavulanic Acid in Pharmaceutical Formulations

2009 ◽  
Vol 92 (4) ◽  
pp. 1089-1094
Author(s):  
Tai-Li Tsou ◽  
Chiu-Wey Lee ◽  
Hsian-Jenn Wang ◽  
Ya-Chung Cheng ◽  
Yu-Tien Liu ◽  
...  
Keyword(s):  
Clavulanic Acid ◽  
Simultaneous Determination ◽  
Flow Rate ◽  
Ammonium Acetate ◽  
Pharmaceutical Formulations ◽  
Hplc Method ◽  
Low Flow ◽  
Hplc Separation ◽  
Accuracy And Precision

Abstract A new HPLC method has been developed and validated for the simultaneous determination of ticarcillin (TIC) and clavulanic acid (CA) in pharmaceutical formulations. The HPLC separation was achieved on a -cyclodextrin column (Cyclobond I, 250 4.6 mm, 5 mm) with methanol16 mM pH 6.0 ammonium acetate buffer (50 + 50, v/v) mobile phase at a flow rate of 0.8 mL/min. Detection was at 220 nm. Validation of the method was performed by evaluating specificity, robustness, accuracy, and precision. The calibration curves were linear in the range of 1100 g/mL for CA and 2200 g/mL for TIC. The LOQs based on the standard regression lines were 0.42 and 1.42 g/mL for CA and TIC, respectively, and the LOD were 0.14 and 0.47 g/mL, respectively. Total recoveries of synthetic mixtures (CA:TIC = 1:10, 1:15, and 1:30) were 99.25100.99 for CA and 99.54100.82 for TIC. Compared with the U.S. Pharmacopeia method, the proposed method has the advantage of a relatively low flow rate and short analysis time. The proposed method was successfully applied for the simultaneous determination of these two drugs in sterilized H2O and 5 dextrose injection solutions.

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