The Experts below are selected from a list of 8535 Experts worldwide ranked by ideXlab platform
Bertrand Souweine - One of the best experts on this subject based on the ideXlab platform.
-
Very high volume hemofiltration with the Cascade System in septic shock patients
Intensive Care Medicine, 2015Co-Authors: Jeanpierre Quenot, Christine Binquet, Christophe Vinsonneau, Saberdavid Barbar, Sandrine Vinault, Valerie Deckert, Stephanie Lemaire, Ali Ait Hassain, Remi Bruyere, Bertrand SouweineAbstract:Purpose We compared hemodynamic and biological effects of the Cascade System, which uses very high volume hemofiltration (HVHF) (120 mL kg^−1 h^−1), with those of usual care in patients with septic shock. Methods Multicenter, prospective, randomized, open-label trial in three intensive care units (ICU). Adults with septic shock with administration of epinephrine/norepinephrine were eligible. Patients were randomized to usual care plus HVHF (Cascade group), or usual care alone (control group). Primary end point was the number of catecholamine-free days up to 28 days after randomization. Secondary end points were number of days free of mechanical ventilation, renal replacement therapy (RRT) or ICU up to 90 days, and 7-, 28-, and 90-day mortality. Results We included 60 patients (29 Cascade, 31 usual care). Baseline characteristics were comparable. Median number of catecholamine-free days was 22 [IQR 11–23] vs 20 [0–25] for Cascade vs control; there was no significant difference even after adjustment. There was no significant difference in number of mechanical ventilation-free days or ICU requirement. Median number of RRT-free days was 85 [46–90] vs 74 [0–90] for Cascade vs control groups, p = 0.42. By multivariate analysis, the number of RRT-free days was significantly higher in the Cascade group (up to 25 days higher after adjustment). There was no difference in mortality at 7, 28, or 90 days. Conclusion Very HVHF using the Cascade System can safely be used in patients presenting with septic shock, but it was not associated with a reduction in the need for catecholamines during the first 28 days.
-
very high volume hemofiltration with the Cascade System in septic shock patients
Intensive Care Medicine, 2015Co-Authors: Jeanpierre Quenot, Christine Binquet, Christophe Vinsonneau, Saberdavid Barbar, Sandrine Vinault, Valerie Deckert, Stephanie Lemaire, Ali Ait Hassain, Remi Bruyere, Bertrand SouweineAbstract:Purpose We compared hemodynamic and biological effects of the Cascade System, which uses very high volume hemofiltration (HVHF) (120 mL kg−1 h−1), with those of usual care in patients with septic shock.
Haodong Zhang - One of the best experts on this subject based on the ideXlab platform.
-
stability issues of z z type Cascade System in hybrid energy storage System hess
IEEE Transactions on Power Electronics, 2014Co-Authors: Haodong ZhangAbstract:Stability issues in hybrid energy storage Systems (HESSs) are the major concern, in addition to the control design challenges of individual modules. In this paper, the stability issues of Z + Z type Cascade Systems in HESS are focused. The stability issues of Cascade Systems have been studied for many years. Impedance ratio type criterions in the form of ZS/ZL or ZL/ZS have been proposed to solve these stability issues. However, existing ratio type criteria still have problems in some Cascade Systems. The terminal characteristics of submodule are studied and the different types of Cascade System are defined in this paper. The validity of conventional impedance ratio type criterion would be influenced by the right-half-plane zeros (RHZ) in terminal impedance of submodules in the Z + Z type Cascade System. Two improved criteria are proposed for the Z + Z type Cascade System: one is improved ratio type criterion considering the RHZ in the terminal impedance of the submodule; the other one is sum type criterion which does not need the information about RHZ in terminal impedance of each submodule. Experimental evidences are provided to prove the validity of these two improved criteria.
-
Stability Issues of $Z + Z$ Type Cascade System in Hybrid Energy Storage System (HESS)
IEEE Transactions on Power Electronics, 2014Co-Authors: Haodong ZhangAbstract:Stability issues in hybrid energy storage Systems (HESSs) are the major concern, in addition to the control design challenges of individual modules. In this paper, the stability issues of Z + Z type Cascade Systems in HESS are focused. The stability issues of Cascade Systems have been studied for many years. Impedance ratio type criterions in the form of ZS/ZL or ZL/ZS have been proposed to solve these stability issues. However, existing ratio type criteria still have problems in some Cascade Systems. The terminal characteristics of submodule are studied and the different types of Cascade System are defined in this paper. The validity of conventional impedance ratio type criterion would be influenced by the right-half-plane zeros (RHZ) in terminal impedance of submodules in the Z + Z type Cascade System. Two improved criteria are proposed for the Z + Z type Cascade System: one is improved ratio type criterion considering the RHZ in the terminal impedance of the submodule; the other one is sum type criterion which does not need the information about RHZ in terminal impedance of each submodule. Experimental evidences are provided to prove the validity of these two improved criteria.
Jeanpierre Quenot - One of the best experts on this subject based on the ideXlab platform.
-
Very high volume hemofiltration with the Cascade System in septic shock patients
Intensive Care Medicine, 2015Co-Authors: Jeanpierre Quenot, Christine Binquet, Christophe Vinsonneau, Saberdavid Barbar, Sandrine Vinault, Valerie Deckert, Stephanie Lemaire, Ali Ait Hassain, Remi Bruyere, Bertrand SouweineAbstract:Purpose We compared hemodynamic and biological effects of the Cascade System, which uses very high volume hemofiltration (HVHF) (120 mL kg^−1 h^−1), with those of usual care in patients with septic shock. Methods Multicenter, prospective, randomized, open-label trial in three intensive care units (ICU). Adults with septic shock with administration of epinephrine/norepinephrine were eligible. Patients were randomized to usual care plus HVHF (Cascade group), or usual care alone (control group). Primary end point was the number of catecholamine-free days up to 28 days after randomization. Secondary end points were number of days free of mechanical ventilation, renal replacement therapy (RRT) or ICU up to 90 days, and 7-, 28-, and 90-day mortality. Results We included 60 patients (29 Cascade, 31 usual care). Baseline characteristics were comparable. Median number of catecholamine-free days was 22 [IQR 11–23] vs 20 [0–25] for Cascade vs control; there was no significant difference even after adjustment. There was no significant difference in number of mechanical ventilation-free days or ICU requirement. Median number of RRT-free days was 85 [46–90] vs 74 [0–90] for Cascade vs control groups, p = 0.42. By multivariate analysis, the number of RRT-free days was significantly higher in the Cascade group (up to 25 days higher after adjustment). There was no difference in mortality at 7, 28, or 90 days. Conclusion Very HVHF using the Cascade System can safely be used in patients presenting with septic shock, but it was not associated with a reduction in the need for catecholamines during the first 28 days.
-
very high volume hemofiltration with the Cascade System in septic shock patients
Intensive Care Medicine, 2015Co-Authors: Jeanpierre Quenot, Christine Binquet, Christophe Vinsonneau, Saberdavid Barbar, Sandrine Vinault, Valerie Deckert, Stephanie Lemaire, Ali Ait Hassain, Remi Bruyere, Bertrand SouweineAbstract:Purpose We compared hemodynamic and biological effects of the Cascade System, which uses very high volume hemofiltration (HVHF) (120 mL kg−1 h−1), with those of usual care in patients with septic shock.
K J Weatherill - One of the best experts on this subject based on the ideXlab platform.
-
laser frequency stabilization to excited state transitions using electromagnetically induced transparency in a Cascade System
Applied Physics Letters, 2009Co-Authors: R P Abel, A K Mohapatra, M G Bason, J D Pritchard, K J WeatherillAbstract:We demonstrate laser frequency stabilization to excited state transitions using Cascade electromagnetically induced transparency. Using a room temperature Rb vapor cell as a reference, we stabilize a first diode laser to the D2 transition and a second laser to a transition from the intermediate 5P3/2 state to a highly excited state with principal quantum number n=19–70. A combined laser linewidth of 280±50 kHz over a 100 μs time period is achieved. This method may be applied generally to any Cascade System and allows laser stabilization to an atomic reference in the absence of a direct absorption signal.
Jahar Sarkar - One of the best experts on this subject based on the ideXlab platform.
-
Cascade Refrigeration System with Internal Heat Exchanger: Suitable Natural Refrigerant Pair Selection
Refrigeration and Air-Conditioning, 2014Co-Authors: Jahar SarkarAbstract:In this study, thermodynamic analyses and optimization of various natural fluids as refrigerants in Cascade System with internal heat exchanger have been done to get the suitable pair in a wide range of temperatures based on best System performance (maximum COP) as well as on operating characteristics. Out of the 56 possible combinations of high and low temperature fluids with 8 natural refrigerants (ammonia, carbon dioxide, propane, propylene, n-butane, isobutane, ethane, and ethylene), the primary selection has been done based on the criteria of normal boiling point and critical point of both low and high temperature fluids following the guideline of the operating temperatures of a refrigerant to be within its critical point and normal boiling point. All the selections have been made based on an optimum intermediate temperature leading to maximum cooling COP for an individual pair. The results show that the internal heat exchanger is usefull in Cascade System to improve performance for all natural refrigerants except ammonia. However, it is not justified where ammonia can be applicable as a high temperature refrigerant. Keywords: Cascade refrigeration, internal heat exchanger, natural refrigerants, intermediate temperature, optimization. COP
-
thermodynamic analysis and optimization of a novel n2o co2 Cascade System for refrigeration and heating
International Journal of Refrigeration-revue Internationale Du Froid, 2009Co-Authors: Souvik Bhattacharyya, Anirban Garai, Jahar SarkarAbstract:Abstract In this study, a natural refrigerant based Cascaded System, with nitrous oxide as the low temperature fluid and carbon dioxide as the high temperature fluid, is analyzed for simultaneous cooling and heating applications. Effects of significant design and operating parameters on System performance are studied. Optimization of intermediate pressure for maximum COP for various design and operating parameters are presented as well. Results show that use of internal heat exchanger has marginal influence on System performance. Due to similar thermodynamic properties of nitrous oxide and carbon dioxide, the optimized intermediate temperature turns out to be independent of the performance of gas cooler and evaporator for a given operating condition. Due to the same reason, N 2 O as low temperature fluid and CO 2 as high temperature fluid in a Cascade arrangement exhibit similar behavioural trends in a System where the fluids are swapped.
-
optimization of a co2 c3h8 Cascade System for refrigeration and heating
International Journal of Refrigeration-revue Internationale Du Froid, 2005Co-Authors: Souvik Bhattacharyya, Saumyadip Mukhopadhyay, Ajeet Kumar, R K Khurana, Jahar SarkarAbstract:Conventional working fluids (refrigerants) are being phased out worldwide to combat with the twin menace of ozone layer depletion and global warming and natural refrigerants are fast gaining favour lately. Single stage and multi stage refrigeration Systems fail to widen the gap between heat source and heat sink temperatures required in many industrial applications requiring simultaneous heating and cooling and Cascaded Systems appear to be the best alternative. Modest research has been done in Cascaded Systems based on natural refrigerants thereby offering good potential for research. In this paper, a Cascaded System for simultaneous heating and cooling (refrigeration and heat pump System) with a carbon dioxide based HT cycle and propane based LT cycle for simultaneous refrigeration and heating applications has been analyzed. To facilitate prediction of optimum performance parameters, performance trends with variation in the design parameters and operating variables have been presented in this article. Relevant expressions have been developed to serve as guidelines to the user for selecting appropriate design parameters like intermediate temperature so that the System yields optimum performance. Independently developed property codes have been employed for both carbon dioxide and propane for higher accuracy.
-
Optimization of a CO2–C3H8 Cascade System for refrigeration and heating
International Journal of Refrigeration-revue Internationale Du Froid, 2005Co-Authors: Souvik Bhattacharyya, Saumyadip Mukhopadhyay, Ajeet Kumar, R K Khurana, Jahar SarkarAbstract:Conventional working fluids (refrigerants) are being phased out worldwide to combat with the twin menace of ozone layer depletion and global warming and natural refrigerants are fast gaining favour lately. Single stage and multi stage refrigeration Systems fail to widen the gap between heat source and heat sink temperatures required in many industrial applications requiring simultaneous heating and cooling and Cascaded Systems appear to be the best alternative. Modest research has been done in Cascaded Systems based on natural refrigerants thereby offering good potential for research. In this paper, a Cascaded System for simultaneous heating and cooling (refrigeration and heat pump System) with a carbon dioxide based HT cycle and propane based LT cycle for simultaneous refrigeration and heating applications has been analyzed. To facilitate prediction of optimum performance parameters, performance trends with variation in the design parameters and operating variables have been presented in this article. Relevant expressions have been developed to serve as guidelines to the user for selecting appropriate design parameters like intermediate temperature so that the System yields optimum performance. Independently developed property codes have been employed for both carbon dioxide and propane for higher accuracy.