Journal articles: 'Regenerative cycle'

1

Lv, Jing, Te Te Hu, Zhe Bin He, and Eric Hu. "Theoretical Analysis for the Influence of the Regenerative Process on the Trans-Critical CO₂ Cycle." Advanced Materials Research 860-863 (December 2013): 1633–37. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.1633.

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The trans-critical CO2 refrigeration cycle involving a regenerative process is analyzed in this paper. The thermodynamic performance of the cycles with regeneration and without regeneration has been compared. The optimal circumstance for the regenerative process set in the trans-critical CO2 cycle is given. The impact of the regeneration on the performance of the system under difference operating conditions is also discussed in this article.

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Lv, Jing, Zhe Bin He, Da Zhang Yang, and Xiu Zhi Huang. "Influence of the Regenerative Process on the Trans-Critical CO₂ Cycle." Key Engineering Materials 467-469 (February 2011): 1881–86. http://dx.doi.org/10.4028/www.scientific.net/kem.467-469.1881.

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The trans-critical CO2 cycle usually involves a regenerative process. The regenerative process used in the trans-critical CO2 cycle is analyzed in this paper. The cycle with regeneration and without regeneration had been compared. The circumstance for the regenerative process set in the trans-critical CO2 cycle is given. The impact regeneration made on the performance of the system in difference operating conditions is also discussed in this article.

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Glasserman, Paul. "Regenerative derivatives of regenerative sequences." Advances in Applied Probability 25, no. 01 (1993): 116–39. http://dx.doi.org/10.1017/s0001867800025209.

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Given a parametric family of regenerative processes on a common probability space, we investigate when the derivatives (with respect to the parameter) are regenerative. We primarily consider sequences satisfying explicit, Lipschitz recursions, such as the waiting times in many queueing systems, and show that derivatives regenerate together with the original sequence under reasonable monotonicity or continuity assumptions. The inputs to our recursions are i.i.d. or, more generally, governed by a Harris-ergodic Markov chain. For i.i.d. input we identify explicit regeneration points; otherwise, we use coupling arguments. We give conditions for the expected steady-state derivative to be the derivative of the steady-state mean of the original sequence. Under these conditions, the derivative of the steady-state mean has a cycle-formula representation.

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Glasserman, Paul. "Regenerative derivatives of regenerative sequences." Advances in Applied Probability 25, no. 1 (1993): 116–39. http://dx.doi.org/10.2307/1427499.

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Given a parametric family of regenerative processes on a common probability space, we investigate when the derivatives (with respect to the parameter) are regenerative. We primarily consider sequences satisfying explicit, Lipschitz recursions, such as the waiting times in many queueing systems, and show that derivatives regenerate together with the original sequence under reasonable monotonicity or continuity assumptions. The inputs to our recursions are i.i.d. or, more generally, governed by a Harris-ergodic Markov chain. For i.i.d. input we identify explicit regeneration points; otherwise, we use coupling arguments. We give conditions for the expected steady-state derivative to be the derivative of the steady-state mean of the original sequence. Under these conditions, the derivative of the steady-state mean has a cycle-formula representation.

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Dellenback, P. A. "Improved Gas Turbine Efficiency Through Alternative Regenerator Configuration." Journal of Engineering for Gas Turbines and Power 124, no. 3 (2002): 441–46. http://dx.doi.org/10.1115/1.1451843.

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An alternative configuration for a regenerative gas turbine engine cycle is presented that yields higher cycle efficiencies than either simple or conventional regenerative cycles operating under the same conditions. The essence of the scheme is to preheat compressor discharge air with high-temperature combustion gases before the latter are fully expanded across the turbine. The efficiency is improved because air enters the combustor at a higher temperature, and hence heat addition in the combustor occurs at a higher average temperature. The heat exchanger operating conditions are more demanding than for a conventional regeneration configuration, but well within the capability of modern heat exchangers. Models of cycle performance exhibit several percentage points of improvement relative to either simple cycles or conventional regeneration schemes. The peak efficiencies of the alternative regeneration configuration occur at optimum pressure ratios that are significantly lower than those required for the simple cycle. For example, at a turbine inlet temperature of 1300°C (2370°F), the alternative regeneration scheme results in cycle efficiencies of 50 percent for overall pressure ratios of 22, whereas simple cycles operating at the same temperature would yield efficiencies of only 43.8 percent at optimum pressure ratios of 50, which are not feasible with current compressor designs. Model calculations for a wide range of parameters are presented, as are comparisons with simple and conventional regeneration cycles.

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Zhang, Chao, Jinglun Fu, Pengfei Yuan, and Jianjun Liu. "Guidelines for Optimal Selection of Subcritical Low-Temperature Geothermal Organic Rankine Cycle Configuration Considering Reinjection Temperature Limits." Energies 11, no. 11 (2018): 2878. http://dx.doi.org/10.3390/en11112878.

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General guidelines are proposed to select the optimal subcritical organic Rankine cycle configuration considering reinjection temperature limits for a low-temperature geothermal brine power plant. Saturated/superheated, non-regenerative/regenerative cycles are investigated. Evaporating temperature and overheating degree at the turbine inlet are selected as design variables, and highest plant exergy efficiency is pursued for current optimizations. Through theoretical analysis of mathematical modelling and typical case studies, a simple optimization approach is presented. The new approach consists of up to three judgements on reinjection temperature and evaporating temperature in comparison two optimization calculations along the saturated line and along the given reinjection temperature line. The potential optimal cycle configurations are saturated non-regenerative cycle, saturated regenerative cycle and superheated regenerative cycle. Then, this new optimization approach is applied to obtain optimal cycle configuration and relevant working condition. The working fluids investigated are R245fa, R1234ze(Z), isopentane, and isobutane. The saturated non-regenerative cycle is the optimal cycle when the reinjection temperature limit is equal or less than the optimal reinjection temperature with no reinjection constraint. Otherwise, the reinjection temperature limit influences not only the optimal cycle configuration but also the optimal working condition. Working fluid isobutane always achieves highest plant exergy efficiency for optimal cycles with either reinjection temperature limit.

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Zhang, Junzhi, Chen Lv, Jinfang Gou, and Decong Kong. "Cooperative control of regenerative braking and hydraulic braking of an electrified passenger car." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 226, no. 10 (2012): 1289–302. http://dx.doi.org/10.1177/0954407012441884.

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With the aims of regeneration efficiency and brake comfort, three different control strategies, namely the maximum-regeneration-efficiency strategy, the good-pedal-feel strategy and the coordination strategy for regenerative braking of an electrified passenger car are researched in this paper. The models of the main components related to the regenerative brake and the frictional blending brake of the electric passenger car are built in MATLAB/Simulink. The control effects and regeneration efficiencies of the control strategies in a typical deceleration process are simulated and analysed. Road tests under normal deceleration braking and an ECE driving cycle are carried out. The simulation and road test results show that the maximum-regeneration-efficiency strategy, which causes issues on brake comfort and safety, could hardly be utilized in the regenerative braking system adopted. The good-pedal-feel strategy and coordination strategy are advantageous over the first strategy with respect to the brake comfort and regeneration efficiency. The fuel economy enhanced by the regenerative braking system developed is more than 25% under the ECE driving cycle.

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Frost, T. H., B. Agnew, and A. Anderson. "Optimizations for Brayton-Joule Gas Turbine Cycles." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 206, no. 4 (1992): 283–88. http://dx.doi.org/10.1243/pime_proc_1992_206_045_02.

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Traditionally, the simple Brayton–Joule cycle has been optimized for maximum output and for minimum compressor work with inter-cooling and maximum turbine work with reheat. To these Woods et al. (1) have added optimization for peak efficiency of the simple cycle with internal irreversibilities. The results now presented include both maximum output and peak efficiency for both regenerative and intercool/reheat cycles with internal irreversibilities. Two special cases, for a regenerative cycle and for a non-regenerative cycle with both reheat and intercooling, are identified where the conditions for maximum output and peak efficiency coincide.

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Rice, I. G. "Thermodynamic Evaluation of Gas Turbine Cogeneration Cycles: Part II—Complex Cycle Analysis." Journal of Engineering for Gas Turbines and Power 109, no. 1 (1987): 8–15. http://dx.doi.org/10.1115/1.3240011.

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Complex open gas turbine cycles are analyzed by applying the heat balance method presented in Part I of this paper. Reheating, intercooling, regeneration, steam injection, and steam cooling are evaluated graphically to give a visual perspective of what takes place in terms of the overall heat balance when such complexities are introduced to the cycle. An example of a viable, new, intercooled regenerative cycle is given. A second example of a prototype reheat gas turbine is also included. The overall approach using the heat balance method can be applied to various cogeneration configurations when considering the more complex cycles of the future.

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Wang, Jun Yi, Gildas Diguet, Guo Xing Lin, and Jin Can Chen. "Performance Characteristics of a Magnetic Ericsson Refrigeration Cycle Using La(Fe_0.88Si_0.12)₁₃H₁ or Gd as the Working Substance." Advanced Materials Research 631-632 (January 2013): 322–25. http://dx.doi.org/10.4028/www.scientific.net/amr.631-632.322.

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Based on the experimental characteristics of iso-field entropy varying with temperature for the room-temperature magnetic refrigeration material La(Fe0.88Si0.12)13H1 or Gd, the regenerative Ericsson refrigeration cycle using La(Fe0.88Si0.12)13H1 or Gd as the working substance is established and their thermodynamic performances are evaluated and analyzed. By means of numerical calculation, the influence of non-perfect regeneration on the main thermodynamic performances of the cycle is revealed and discussed. Furthermore, the coefficient of performance (COP), non-perfect regenerative heat quantity, and net cooling quantity of the Ericsson refrigeration cycle using La(Fe0.88Si0.12)13H1 or Gd as the working substance are compared. The results obtained show that it is beneficial to the cooling quantity of the cycles using La(Fe0.88Si0.12)13H1 or Gd as the working substance to operate in the region of Tcold >T0 and, at the condition of a same temperature span, the cooling quantity for La(Fe0.88Si0.12)13H1 is larger than that for Gd.

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Zebrowski, David C., Robert Becker, and Felix B. Engel. "Towards regenerating the mammalian heart: challenges in evaluating experimentally induced adult mammalian cardiomyocyte proliferation." American Journal of Physiology-Heart and Circulatory Physiology 310, no. 9 (2016): H1045—H1054. http://dx.doi.org/10.1152/ajpheart.00697.2015.

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In recent years, there has been a dramatic increase in research aimed at regenerating the mammalian heart by promoting endogenous cardiomyocyte proliferation. Despite many encouraging successes, it remains unclear if we are any closer to achieving levels of mammalian cardiomyocyte proliferation for regeneration as seen during zebrafish regeneration. Furthermore, current cardiac regenerative approaches do not clarify whether the induced cardiomyocyte proliferation is an epiphenomena or responsible for the observed improvement in cardiac function. Moreover, due to the lack of standardized protocols to determine cardiomyocyte proliferation in vivo, it remains unclear if one mammalian regenerative factor is more effective than another. Here, we discuss current methods to identify and evaluate factors for the induction of cardiomyocyte proliferation and challenges therein. Addressing challenges in evaluating adult cardiomyocyte proliferation will assist in determining 1) which regenerative factors should be pursued in large animal studies; 2) if a particular level of cell cycle regulation presents a better therapeutic target than another (e.g., mitogenic receptors vs. cyclins); and 3) which combinatorial approaches offer the greatest likelihood of success. As more and more regenerative studies come to pass, progress will require a system that not only can evaluate efficacy in an objective manner but can also consolidate observations in a meaningful way.

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Zhang, Yue, Congjie Ou, Bihong Lin, and Jincan Chen. "The Regenerative Criteria of an Irreversible Brayton Heat Engine and its General Optimum Performance Characteristics." Journal of Energy Resources Technology 128, no. 3 (2005): 216–22. http://dx.doi.org/10.1115/1.2213272.

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An irreversible cycle model of the Brayton heat engine is established, in which the irreversibilities resulting from the internal dissipation of the working substance in the adiabatic compression and expansion processes and the finite-rate heat transfer in the regenerative and constant-pressure processes are taken into account. The power output and efficiency of the cycle are expressed as functions of temperatures of the working substance and the heat sources, heat transfer coefficients, pressure ratio, regenerator effectiveness, and total heat transfer area including the heat transfer areas of the regenerator and other heat exchangers. The regenerative criteria are given. The power output is optimized for a given efficiency. The general optimal performance characteristics of the cycle are revealed. The optimal performance of the Brayton heat engines with and without regeneration is compared quantitatively. The advantages of using the regenerator are expounded. Some important parameters of an irreversible regenerative Brayton heat engine, such as the temperatures of the working substance at different states, pressure ratio, maximum value of the pressure ratio, regenerator effectiveness and ratios of the various heat transfer areas to the total heat transfer area of the cycle, are further optimized. The optimal relations between these parameters and the efficiency of the cycle are presented by a set of characteristic curves for some assumed compression and expansion efficiencies. The results obtained may be helpful to the comprehensive understanding of the optimal performance of the Brayton heat engines with and without regeneration and play a theoretical instructive role for the optimal design of a regenerative Brayton heat engine.

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13

Weiwu, Wan. "Adiabatic expansion-exhaust regenerative refrigerating cycle." Cryogenics 27, no. 10 (1987): 577–81. http://dx.doi.org/10.1016/0011-2275(87)90181-0.

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14

Cunha, André Felippe Vieira da, and Sandino Lamarca Santos Souza. "Analysis of R134a Organic Regenerative Cycle." Journal of Power and Energy Engineering 08, no. 05 (2020): 32–45. http://dx.doi.org/10.4236/jpee.2020.85003.

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15

Khalatov, A. A., S. D. Severin, O. S. Stupak, and O. V. Shihabutinova. "EFFICIENCY OF THE REGENERATIVE CYCLE OF BRIGHTON WITH VARIABLE THERMOPHYSICAL PROPERTIES OF THE WORKING FLUID (Part 2)." Thermophysics and Thermal Power Engineering 41, no. 3 (2018): 5–13. http://dx.doi.org/10.31472/ttpe.3.2019.1.

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The data about thermodynamic efficiency of the ideal Brighton cycle with heat regeneration with constant thermophysical properties of the working fluid, as well as the Brighton cycle with heat recovery and the wetting of the working fluid at the inlet to the turbine (with variable thermophysical properties of the working fluid). The inapplicability of comparison of the thermal efficiency of the Brighton cycle with heat recovery and the wetting of the working fluid at the inlet to the turbine with the thermal efficiency of the equivalent ideal Carnot cycle is shown. The analysis of the thermodynamic efficiency of an ideal regenerative Brighton cycle with a decrease in the working body at the entrance to the turbine allows us to make the following conclusions:  With the growth of the mass moisture content of the working fluid when entering the turbine, the thermal efficiency of the regenerative cycle increases, but decreases with an increase in the degree of increase in the pressure level in the cycle. High values of the thermal efficiency of the cycle () can be achieved with relatively small values of the degree of increase in the pressure in the cycle () and high (up to d = 0,5) values of the mass moisture content of the working body when entering the turbine. It is shown that under certain conditions the thermal efficiency of the regenerative cycle with the decrease of the working body when entering the turbine may be greater than the thermal efficiency of a similar ideal Carnot cycle, which does not contradict the second law of thermodynamics, since the condition for the implementation of the Carnot cycle is the immutability of the thermophysical properties of the working body in a loop In this regard, the use of the expression for the thermal efficiency of the ideal Carnot cycle is not used as a criterion for assessing the efficiency of cycles of power plants with highly variable thermophysical properties of the working fluid. It is also shown that the thermal efficiency of the regenerative cycle with the decrease of the working body when entering the turbine is always lower than the thermal efficiency of the equivalent non-equilibrium Carnot cycle with a change in the specific heat of the working fluid, which corresponds to the second law of thermodynamics. It is shown that the Brighton regenerative cycle with a decrease in the working body before the turbine can be represented as a conditional cycle with a higher maximum temperature of the cycle, which, depending on the mass content of the moisture content of the working body, can in 1,2 ... 2,5 times exceed the actual maximum temperature cycle, which determines the high values of its thermal efficiency.

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Liu, Wei Min, Feng Yun Chen, Yi Qiang Wang, Wei Jun Jiang, and Ji Guang Zhang. "Progress of Closed-Cycle OTEC and Study of a New Cycle of OTEC." Advanced Materials Research 354-355 (October 2011): 275–78. http://dx.doi.org/10.4028/www.scientific.net/amr.354-355.275.

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OTEC has the advantages of large reserves, renewable, stable and clean without pollution. However the smaller ocean temperature-difference results in the lower thermal efficiency. Based on the research of Rankine cycle, Kalina cycle, Uehara cycle, a new closed-cycle system (GuoHai cycle) has been studied, this cycle system uses ammonia-water mixtures as working medium. Indirect regenerative cycle and poor ammonia solution regenerative cycle is adopted in order to improve the thermal efficiency of the system.

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YURCO, PATRICK, and DAVID A. CAMERON. "Cellular correlates of proneural and notch-delta gene expression in the regenerating zebrafish retina." Visual Neuroscience 24, no. 3 (2007): 437–43. http://dx.doi.org/10.1017/s0952523807070496.

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Fish can regenerate retinal neurons following ocular injury. Evidence is mounting that astrocytic glia function as inducible, regenerative stem cells in this process, but the underlying molecular events that enable neuronal regeneration are comparatively unclear. In the current study gene array, quantitative real-time PCR, in situ hybridization, and immunohistochemical approaches were used to identify, in the damaged retina of adult zebrafish, correlations between transcriptional events and entry into the cell cycle by Müller cells, a type of astrocytic cell present in all vertebrate retinas that is a candidate ‘stem cell’ of regenerated neurons. A proneural gene (achaete-scute homolog 1a, ash1a) and neurogenic components of the Notch signaling pathway, including notch3 and deltaA, were implicated. An injury-induced, enhanced expression of ash1a was observed in Müller cells, which is hypothesized to contribute to the transition of these cells, or their cellular progeny, into a notch3-expressing, regenerative progenitor. A model of vertebrate retinal repair is suggested in which damage-induced expression of proneural genes, plus canonical Notch-Delta signaling, could contribute to retinal stem cell promotion and subsequent regenerative neurogenesis.

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T. SAITO, Akiko, Shiori KAJI, Tadahiko KOBAYASHI, and Hideki NAKAGOME. "Characterization of an Active Magnetic Regenerative Cycle." TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan) 50, no. 2 (2015): 88–95. http://dx.doi.org/10.2221/jcsj.50.88.

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Aragón-González, G., M. Cano-Bianco, A. León-Galicia, and J. M. Rivera-Camacho. "Optimization of an irreversible Stirling regenerative cycle." Journal of Physics: Conference Series 582 (January 14, 2015): 012056. http://dx.doi.org/10.1088/1742-6596/582/1/012056.

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20

Chen, Guobang, Zhihua Gan, and Yanlong Jiang. "Discussion on refrigeration cycle for regenerative cryocoolers." Cryogenics 42, no. 2 (2002): 133–39. http://dx.doi.org/10.1016/s0011-2275(02)00017-6.

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21

Korakianitis, T., and D. G. Wilson. "Models for Predicting the Performance of Brayton-Cycle Engines." Journal of Engineering for Gas Turbines and Power 116, no. 2 (1994): 381–88. http://dx.doi.org/10.1115/1.2906831.

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Gas turbine performance is the result of choices of type of cycle, cycle temperature ratio, pressure ratio, cooling flows, and component losses. The output is usually given as efficiency (thermal, propulsive, specific thrust, overall efficiency) versus specific power. This paper presents a set of computer programs for the performance prediction of shaft-power and jet-propulsion cycles: simple, regenerative, intercooled-regenerative, turbojet, and turbofan. Each cycle is constructed using individual component modules. Realistic assumptions are specified for component efficiencies as functions of pressure ratio, cooling mass-flow rate as a function of cooling technology levels, and various other cycle losses. The programs can be used to predict design point and off-design point operation using appropriate component efficiencies. The effects of various cycle choices on overall performance are discussed.

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Morehouse, J. H. "Thermally Regenerative Hydrogen/Oxygen Fuel Cell Power Cycles." Journal of Solar Energy Engineering 110, no. 2 (1988): 107–12. http://dx.doi.org/10.1115/1.3268239.

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Two thermodynamic power cycles are analytically examined for future engineering feasibility. These power cycles use a hydrogen-oxygen fuel cell for electrical energy production and use the thermal dissociation of water for regeneration of the hydrogen and oxygen. The first cycle uses a thermal energy input at over 2000K to thermally dissociate the water. The second cycle dissociates the water using an electrolyzer operating at high temperature (1300K) which receives both thermal and electrical energy as inputs. The results show that while the processes and devices of the 2000K thermal system exceed current technology limits, the high temperature electrolyzer system appears to be a state-of-the-art technology development, with the requirements for very high electrolyzer and fuel cell efficiencies seen as determining the feasibility of this system.

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Trela, Marian, Roman Kwidziński, and Dariusz Butrymowicz. "A study of transcritical carbon dioxide cycles with heat regeneration." Archives of Thermodynamics 34, no. 3 (2013): 197–217. http://dx.doi.org/10.2478/aoter-2013-0025.

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Abstract The paper presents an efficiency analysis of two transcritical CO2 power cycles with regenerative heaters. For the proposed cycles, calculations of thermal efficiency are given for selected values of operating parameters. It was assumed that the highest working temperature and pressure are in the range from 600 to 700 °C and 40 to 50 MPa, respectively. The purpose of the calculations was optimization of the pressure and mass flows in the regenerative heaters to achieve maximum cycle efficiency. It follows that for the assumed upper CO2 parameters, efficiency of 51-54% can be reached, which is comparable to the efficiency of a supercritical advanced power cycle considered by Dostal.

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Chen, Lingen, Huijun Feng, and Yanlin Ge. "Power and Efficiency Optimization for Open Combined Regenerative Brayton and Inverse Brayton Cycles with Regeneration before the Inverse Cycle." Entropy 22, no. 6 (2020): 677. http://dx.doi.org/10.3390/e22060677.

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A theoretical model of an open combined cycle is researched in this paper. In this combined cycle, an inverse Brayton cycle is introduced into regenerative Brayton cycle by resorting to finite-time thermodynamics. The constraints of flow pressure drop and plant size are taken into account. Thirteen kinds of flow resistances in the cycle are calculated. On the one hand, four isentropic efficiencies are used to evaluate the friction losses in the blades and vanes. On the other hand, nine kinds of flow resistances are caused by the cross-section variances of flowing channels, which exist at the entrance of top cycle compressor (TCC), the entrance and exit of regenerator, the entrance and exit of combustion chamber, the exit of top cycle turbine, the exit of bottom cycle turbine, the entrance of heat exchanger, as well as the entrance of bottom cycle compressor (BCC). To analyze the thermodynamic indexes of power output, efficiency along with other coefficients, the analytical formulae of these indexes related to thirteen kinds of pressure drop losses are yielded. The thermodynamic performances are optimized by varying the cycle parameters. The numerical results reveal that the power output presents a maximal value when the air flow rate and entrance pressure of BCC change. In addition, the power output gets its double maximal value when the pressure ratio of TCC further changes. In the premise of constant flow rate of working fuel and invariant power plant size, the thermodynamic indexes can be optimized further when the flow areas of the components change. The effect of regenerator on thermal efficiency is further analyzed in detail. It is reported that better thermal efficiency can be procured by introducing the regenerator into the combined cycle in contrast with the counterpart without the regenerator as the cycle parameters change in the critical ranges.

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Magadum, Ajit, Neha Singh, Ann Anu Kurian, et al. "Pkm2 Regulates Cardiomyocyte Cell Cycle and Promotes Cardiac Regeneration." Circulation 141, no. 15 (2020): 1249–65. http://dx.doi.org/10.1161/circulationaha.119.043067.

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Background: The adult mammalian heart has limited regenerative capacity, mostly attributable to postnatal cardiomyocyte cell cycle arrest. In the last 2 decades, numerous studies have explored cardiomyocyte cell cycle regulatory mechanisms to enhance myocardial regeneration after myocardial infarction. Pkm2 (Pyruvate kinase muscle isoenzyme 2) is an isoenzyme of the glycolytic enzyme pyruvate kinase. The role of Pkm2 in cardiomyocyte proliferation, heart development, and cardiac regeneration is unknown. Methods: We investigated the effect of Pkm2 in cardiomyocytes through models of loss (cardiomyocyte-specific Pkm2 deletion during cardiac development) or gain using cardiomyocyte-specific Pkm2 modified mRNA to evaluate Pkm2 function and regenerative affects after acute or chronic myocardial infarction in mice. Results: Here, we identify Pkm2 as an important regulator of the cardiomyocyte cell cycle. We show that Pkm2 is expressed in cardiomyocytes during development and immediately after birth but not during adulthood. Loss of function studies show that cardiomyocyte-specific Pkm2 deletion during cardiac development resulted in significantly reduced cardiomyocyte cell cycle, cardiomyocyte numbers, and myocardial size. In addition, using cardiomyocyte-specific Pkm2 modified RNA, our novel cardiomyocyte-targeted strategy, after acute or chronic myocardial infarction, resulted in increased cardiomyocyte cell division, enhanced cardiac function, and improved long-term survival. We mechanistically show that Pkm2 regulates the cardiomyocyte cell cycle and reduces oxidative stress damage through anabolic pathways and β-catenin. Conclusions: We demonstrate that Pkm2 is an important intrinsic regulator of the cardiomyocyte cell cycle and oxidative stress, and highlight its therapeutic potential using cardiomyocyte-specific Pkm2 modified RNA as a gene delivery platform.

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Mitov, K. V., and N. M. Yanev. "Regenerative processes in the infinite mean cycle case." Journal of Applied Probability 38, no. 01 (2001): 165–79. http://dx.doi.org/10.1017/s0021900200018581.

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A class of non-negative alternating regenerative processes is considered, where the process stays at zero random time (waiting period), then it jumps to a random positive level and hits zero after some random period (life period), depending on the evolution of the process. It is assumed that the waiting time and the lifetime belong to the domain of attraction of stable laws with parameters in the interval (½,1]. An integral representation for the distribution functions of the regenerative process is obtained, using the spent time distributions of the corresponding alternating renewal process. Given the asymptotic behaviour of the process in the regenerative cycle, different types of limiting distributions are proved, applying some new results for the corresponding renewal process and two limit theorems for the convergence in distribution.

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Mitov, K. V., and N. M. Yanev. "Regenerative processes in the infinite mean cycle case." Journal of Applied Probability 38, no. 1 (2001): 165–79. http://dx.doi.org/10.1239/jap/996986651.

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A class of non-negative alternating regenerative processes is considered, where the process stays at zero random time (waiting period), then it jumps to a random positive level and hits zero after some random period (life period), depending on the evolution of the process. It is assumed that the waiting time and the lifetime belong to the domain of attraction of stable laws with parameters in the interval (½,1]. An integral representation for the distribution functions of the regenerative process is obtained, using the spent time distributions of the corresponding alternating renewal process. Given the asymptotic behaviour of the process in the regenerative cycle, different types of limiting distributions are proved, applying some new results for the corresponding renewal process and two limit theorems for the convergence in distribution.

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Yuan, Wang, Gildas Diguet, Guo Xing Lin, and Jin Can Chen. "Performance Analysis of the Regenerative Brayton Refrigeration Cycle Using Gd_0.94Er_0.06 as the Working Substance." Advanced Materials Research 631-632 (January 2013): 318–21. http://dx.doi.org/10.4028/www.scientific.net/amr.631-632.318.

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Based on the experimental data of entropy change varying with temperature, the regenerative Brayton refrigeration cycle using Gd0.94Er0.06 as the working substance is set up for magnetic field changes with 0-1T and 0-2T. By using thermodynamic analysis method, some parameters such as the non-perfect regeneration, net cooling quantity, coefficient of performance (COP), and so on, are analyzed and calculated. The effects of temperature of the heat reservoir, regeneration and external magnetic field are also discussed. The results obtained in the present paper show that the refrigeration cycle operating in TC=T0, TH= T0+7K and 0-2T magnetic field change has not only maximum cooling quantity but also maximum COP in all the established magnetic refrigeration cycles, and can provide some new guide for the optimal design of real room-temperature magnetic refrigerators.

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Chen, F. C., R. W. Murphy, V. C. Mei, and G. L. Chen. "Thermodynamic Analysis of Four Magnetic Heat-Pump Cycles." Journal of Engineering for Gas Turbines and Power 114, no. 4 (1992): 715–20. http://dx.doi.org/10.1115/1.2906647.

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Magnetic heat pumps have been successfully used for refrigeration applications at near absolute-zero-degree temperatures. In these applications, a temperature lift of a few degrees in a cryogenic environment is sufficient and can be easily achieved by a simple magnetic heat-pump cycle. To extend magnetic heat pumping to other temperature ranges and other types of application in which the temperature lift is more than just a few degrees requires more involved cycle processes. The possible cycle applications include cooling of superconducting transmission lines, space conditioning, and industrial heating. This paper investigates the characteristics of a few better-known thermomagnetic heat-pump cycles (Carnot, Ericsson, Stirling, and regenerative) in extended ranges of temperature lift. The regenerative cycle is the most efficient one. Cycle analyses were done for gadolinium operating between 0 and 7 Tesla, and with a heat-rejection temperature of 320 K. The analysis results predicted a 42 percent reduction in coefficient of performance at 260 K cooling temperature and a 15 percent reduction in capacity at 232 K cooling temperature for the magnetic Ericsson cycle as compared with the ideal regenerative cycle. Such substantial penalties indicate that the potential irreversibilities from this one source may adversely affect the viability of certain proposed MHP concepts if the relevant loss mechanisms are not adequately addressed.

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Chen, Lingen, Zelong Zhang, and Fengrui Sun. "Thermodynamic Modeling for Open Combined Regenerative Brayton and Inverse Brayton Cycles with Regeneration before the Inverse Cycle." Entropy 14, no. 1 (2012): 58–73. http://dx.doi.org/10.3390/e14010058.

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Santoso, Habibi. "Optimalisasi untuk Menghasilkan Efisiensi Ideal Turbin Uap Pembangkit Listrik TenagaBiomassa Kapasitas 20 MW." STRING (Satuan Tulisan Riset dan Inovasi Teknologi) 3, no. 2 (2018): 181. http://dx.doi.org/10.30998/string.v3i2.3044.

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The energy crisis is one of the problems facing by Indonesia. One solution to overcome this problem is turning waste into electricity, leading to a solution to the long-standing waste problems in many areas in Indonesia. This research is part of the initial design of PLTU with Biomassa (Waste) energy sources. This research covers the initial design of the rankine cycle that includes determining the type of turbine to be used, whether the reaction turbine or impulse turbine and the number of turbine shaft and determining a simple, regenerative cycle or another modified cycle. The step taken is comparing thermodinamically the advantages and disadvantages of the simple rankine cycle with the regenerative cycle. The parameters used as the standard of comparison are thermal efficiency, net work and work ratio. From the calculation results, it is determined to use a steam turbine with the type of one-shaft impulse turbine using a regenerative cycle with 3 feedwater heaters because it can increase efficiency up to 50% when compared to a simple regenerative cycle with efficiency of 37%.

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Pacak, Anna, Aleksandra Cichoń, Demis Pandelidis, and Sergey Anisimov. "Impact of indirect evaporative air cooler type on the performance of desiccant systems." E3S Web of Conferences 44 (2018): 00134. http://dx.doi.org/10.1051/e3sconf/20184400134.

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In this study, two different indirect evaporative coolers operating with a desiccant wheel are compared theoretically: System A with the regenerative Maisotsenko Cycle (M-Cycle) unit and System B with the cross-flow M-cycle unit. Each system component performance was simulated using the original ε-NTU model. The influence of selected operational factors, such as inlet air temperature, humidity and regeneration air temperature for two system configurations was analysed and compared. It was established, that System B obtains higher cooling capacities and is more sensitive on ambient air humidity changes than System A.

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Grzesiak, Szymon, and Andrzej Adamkiewicz. "Application of Steam Jet Injector for Latent Heat Recovery of Marine Steam Turbine Propulsion Plant." New Trends in Production Engineering 1, no. 1 (2018): 235–44. http://dx.doi.org/10.2478/ntpe-2018-0030.

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Abstract This paper presents the results of previously carried out analyses regarding efficiency and criteria evaluation of various propulsion plants of modern LNG (Liquid Natural Gas) carriers. The results of previous identification and quality assessment of waste heat energy sources of a CST (Conventional Steam Turbine) plant are presente. In this paper the possibility of use a steam jet injector in order to recover the latent heat is analysed. Calculations were carried out for an injector equipped with a de Laval nozzle, determining the thermodynamic state parameters of the mixture of drive steam and sucked in steam as well as the steam on the outlet of the injector for the various ejection ratios. On the basis of the results of the injector calculation, the heat balance of a simple regenerative Clausius – Rankine steam cycle (with one regenerative heater – deaerator) was carried out. The degree of regeneration (increase of the thermal efficiency) for cycle using the regenerative injector was determined. Based on results the further research directions for complex plants using a steam jets are indicated.

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Kim, Kyoung Hoon, and Man Hoe Kim. "Thermodynamic Performance Analysis of Regenerative Organic Flash Cycle." Transactions of the Korean Society of Mechanical Engineers B 40, no. 9 (2016): 589–96. http://dx.doi.org/10.3795/ksme-b.2016.40.9.589.

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Roco, J. M. M., S. Velasco, A. Medina, and A. Calvo Hernández. "Optimum performance of a regenerative Brayton thermal cycle." Journal of Applied Physics 82, no. 6 (1997): 2735–41. http://dx.doi.org/10.1063/1.366104.

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Cheng, Ching-Yang, and Cha'o-Kuang Chen. "Power optimization of an endoreversible regenerative Brayton cycle." Energy 21, no. 4 (1996): 241–47. http://dx.doi.org/10.1016/0360-5442(95)00126-3.

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Duan, Jiandong, Li Sun, Guanglin Wang, and Fengjiang Wu. "Nonlinear modeling of regenerative cycle micro gas turbine." Energy 91 (November 2015): 168–75. http://dx.doi.org/10.1016/j.energy.2015.07.134.

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Long, Rui, Baode Li, Zhichun Liu, and Wei Liu. "Ecological analysis of a thermally regenerative electrochemical cycle." Energy 107 (July 2016): 95–102. http://dx.doi.org/10.1016/j.energy.2016.04.004.

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Cheng, C. Y., and C. K. Chen. "Power optimization of an endoreversible regenerative Brayton cycle." Fuel and Energy Abstracts 37, no. 3 (1996): 233. http://dx.doi.org/10.1016/0140-6701(96)89296-4.

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Liu, Chao, Xi Wang, Hong Gao, Cheng Zhang, and Chao He. "The injector-based regenerative supercritical organic Rankine cycle." Journal of Mechanical Science and Technology 30, no. 5 (2016): 2353–60. http://dx.doi.org/10.1007/s12206-016-0445-6.

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Hindley, Christopher, and Anna Philpott. "The cell cycle and pluripotency." Biochemical Journal 451, no. 2 (2013): 135–43. http://dx.doi.org/10.1042/bj20121627.

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PSCs (pluripotent stem cells) possess two key properties that have made them the focus of global research efforts in regenerative medicine: they have unlimited expansion potential under conditions which favour their preservation as PSCs and they have the ability to generate all somatic cell types upon differentiation (pluripotency). Conditions have been defined in vitro in which pluripotency is maintained, or else differentiation is favoured and is directed towards specific somatic cell types. However, an unanswered question is whether or not the core cell cycle machinery directly regulates the pluripotency and differentiation properties of PSCs. If so, then manipulation of the cell cycle may represent an additional tool by which in vitro maintenance or differentiation of PSCs may be controlled in regenerative medicine. The present review aims to summarize our current understanding of links between the core cell cycle machinery and the maintenance of pluripotency in ESCs (embryonic stem cells) and iPSCs (induced PSCs).

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DOLOGLONYAN, A. V., and V. T. MATVIINKO. "DEGREE OF REGENERATION OPTIMIZATION FOR CYCLES OF MICROGAS TURBINE PLANTS." Fundamental and Applied Problems of Engineering and Technology 3 (2020): 59–66. http://dx.doi.org/10.33979/2073-7408-2020-341-3-59-66.

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A consideration subject in article is the mathematical model of pressure recovery factor of microgas turbine plants (MGTP) regenerators which considers dependence of hydraulic resistance of the heat–exchanger on the its surface area. Optimization of a regenerative cycle of MGTP and a cycle with regeneration and the turbocompressor utilizer for the purpose of further increase in their profitability is performed. It is established that use of the offered model of pressure recovery factor on the air and gas side allows to find degree of regeneration heattechnical optimum. This model can be used at simplified and predesign of MGTP.

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Tarrad, Ali H. "A Perspective Evolution Methodology of Energy Management in a Subcritical Regenerative Organic Rankine Cycles Operate at Two Temperature Levels." Athens Journal of Τechnology & Engineering 8, no. 1 (2021): 9–26. http://dx.doi.org/10.30958/ajte.8-1-1.

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The waste energy recovery and management philosophy represent a great challenge for scientists. This article outlines a scheme to utilize two different source temperature levels in the range of (160–200) °C. Two regenerative organic Rankine cycles (RORC) were implemented to construct a compound regenerative organic Rankine cycle (CRORC) to improve the energy management of the sources. The method of energy management for these cycles was accomplished by extracting a certain amount of energy from the high-temperature cycle and rejecting it to the working fluid in an economizer at the low-temperature level. R-123 was circulated in the high-temperature cycle due to its high critical temperature at evaporation and condensation temperatures of 150 °C and 50 °C respectively. R-123, R-245fa, R-1233zd-E, and the hydrocarbon R-600a were used as working fluids for the low-temperature cycle at evaporation and condensation temperatures of 130 °C and 35 °C respectively. This technique showed that the first law of thermodynamics efficiency was augmented by (3–5)% for the low-temperature mini-cycle of the (CRORC). The energy consumption at the low-temperature cycle was also reduced by (3–5)%. The latter reduction range accounts for 2% for the total extracted energy for the independent system where both high-temperature and low-temperature cycles were utilized separately. The data showed that increasing the superheat degree from 10 °C to 20°C has enhanced the thermal efficiency of the compound (CRORC) system by (2–4)%. The (CRORC) system of R-123/R600a, R-123/R-123, and R-123/R-245fa fluid pairs exhibited higher thermal efficiency than that of R-123/R-1233zd-E pair by (4.5–6)%, (4–6)% and (3–4)% respectively. The net thermal efficiency of the compound (CRORC) system fell in the range (12–13)% and the low-temperature mini-cycle of the (CRORC) system had a range of (12–14)% for all of the examined operating conditions. Keywords: compound cycle, regenerative, energy management, energy recovery

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Abed, Saria, Taher Khir, and Ammar Ben Brahim. "Thermodynamic and Energy Study of a Regenerator in Gas Turbine Cycle and Optimization of Performances." International Journal of Energy Optimization and Engineering 5, no. 2 (2016): 25–44. http://dx.doi.org/10.4018/ijeoe.2016040102.

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In this paper, thermodynamic study of simple and regenerative gas turbine cycles is exhibited. Firstly, thermodynamic models for both cycles are defined; thermal efficiencies of both cycles are determined, the overall heat transfer coefficient through the heat exchanger is calculated in order to determinate its performances and parametric study is carried out to investigate the effects of compressor inlet temperature, turbine inlet temperature and compressor pressure ratio on the parameters that measure cycles' performance. Subsequently, numerical optimization is established through EES software to determinate operating conditions. The results of parametric study have shown a significant impact of operating parameters on the performance of the cycle. According to this study, the regeneration technique improves the thermal efficiency by 10%. The studied regenerator has an important effectiveness (˜ 82%) which improves the heat transfer exchange; also a high compressor pressure ratio and an important combustion temperature can increase thermal efficiency.

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FIRMANTO, DANIEL RAHADIAN, SLAMET RIYADI, LEONARDUS HERU PRATOMO, and FLORENTINUS BUDI SETIAWAN. "Pengoptimalan Kinerja Pengereman Regeneratif Motor BLDC menggunakan Cascaded Boost Converter." ELKOMIKA: Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & Teknik Elektronika 9, no. 2 (2021): 444. http://dx.doi.org/10.26760/elkomika.v9i2.444.

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ABSTRAKMesin Brushless Dircet Current (BLDC) digunakan pada kendaraan listrik karena memiliki torsi yang besar dan memungkinkan untuk pengereman regeneratif. Pengereman regeneratif dirancang agar kendaraan listrik memiliki jarak tempuh yang lebih panjang. Pada saat pengereman, konverter bidirectional dioperasikan menjadi boost rectifier agar energi dapat berpindah ke baterai. Boost rectifier memiliki gain yang rendah, sehingga pengiriman daya ke baterai kurang optimal. Pada penelitian ini ditambahkan chopper kedua yang memiliki gain tinggi agar pengiriman daya lebih optimal. Metode modulasi lebar pulsa yang dibangkitkan mikrokontrol dsPIC30f4012 digunakan untuk mengendalikan saklar (IRFP 460) pada konverter. Verifikasi menggunakan perangkat keras telah dilakukan untuk mendukung penelitian ini. Hasil percobaan pada duty cycle 0,8 dapat dihasilkan arus pada baterai sebesar 0,25 A dan kecepatan berkurang menjadi 663 rpm.Kata kunci: BLDC, Pengereman regeneratif, Boost rectifier, chopper, dsPIC30f4012 ABSTRACTBrushless direct current (BLDC) machine is suitable to be implemented in electric vehicle since it can provide high torque and is capable to do regenerative braking. For electric vehicle applications, the regenerative braking is needed to make such vehicle can travel longer distance. For making the machine current can flow into the battery, the bidirectional converter will be operated as a boost rectifier. The boost rectifier produced a low gain so that the second chopper with a high gain is required. The pulse width modulation (PWM) method was used to control each switch (IRFP 460) using a dsPIC30F4012 microcontroller. A verification with experimental work was done. Based on the result, with 0.8 duty cycle can produced a 0.2 A battery current also and speed reduced to 663 rpm.Keywords: BLDC, Regenerative braking, Boost rectifier, chopper, dsPIC30f4012

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Mosadegh, Mahdi, Mohammad M. Jalili, and Abbas Mazidi. "A bond graph model for simulating the effects of regenerative braking system on emission of a hybrid vehicle." Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 232, no. 4 (2017): 481–500. http://dx.doi.org/10.1177/1464419317748015.

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Nowadays, vehicles have major role in the transportation of people and goods. The air pollution and fuel consumption are the most important topics in this subject. One of the methods used for reducing fuel consumption is regenerative braking systems. Very few researches have studied the effects of regenerative braking system on emission of hybrid vehicles. In this research, using bond graph method, a vehicle model including combustion, heat transfer, power generation, power transmission, braking, energy storage system and vehicle body is simulated. To determine the amount of pollution generation, an incomplete combustion model and complete gas theory are assumed and Arrhenius equation is used for modelling the combustion reaction velocity. This model can determine fuel consumption in any actual operating condition and also all pollutions generated by incomplete combustion in the engine. This is the preference of this research while most of previous researches using engine fuel map to determine fuel consumption and unable to define all kind of pollutions. The body of the vehicle is modelled with seven degrees of freedom mass-spring-damper model. Also, the hydraulic braking system is modelled by acting braking torque on wheels. Using this vehicle model and its parameters, amount of energy consumption and emission of the vehicle equipped with regenerative braking system are achieved and compared with the results of the same vehicle without regenerative braking system. Simulations are performed on two standard Economic Commission for Europe and extra urban driving cycles to determine regenerative braking system operation effects on reducing fuel consumption and emission in each cycle. Results show that a vehicle with this equipment is capable of reducing fuel consumption and emission in comparing with an unequipped vehicle. Using regenerative braking system in Economic Commission for Europe cycle, in comparing with extra urban driving cycle, is more efficient in reducing emission and fuel consumption. According to the results, regenerative braking system makes more deceleration than Hydraulic Braking System in high speeds.

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Wager, Guido, Jonathan Whale, and Thomas Braunl. "Performance evaluation of regenerative braking systems." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 232, no. 10 (2017): 1414–27. http://dx.doi.org/10.1177/0954407017728651.

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This research evaluates the energy gain from a regenerative braking system (RBS) in a commercial electric vehicle (EV), the OEM Mitsubishi i-MiEV. Measurements were conducted in a controlled environment on a commercial chassis dynamometer using international drive cycle standards. The energy recovery of the vehicle was modelled and the output of the model was compared with results from the chassis dynamometer driving. The experiments were original as they coupled changes in energy recovered and driving range due to the RBS settings with investigations into the time of use of the friction brake. Performance tests used two different drive cycle speed profiles and various RBS settings to compare energy recovery performance for a broad range of driving styles. The results show that due to reduced energy consumption, the RBS increased the driving range by 11–22% depending on RBS settings and the drive cycle settings on the dynamometer. The results further showed that driving an EV with a RBS uses the friction brakes more efficiently, which will reduce brake pad wear. This has the potential to improve air quality due to reduced brake pad dust and reduces the maintenance costs of the vehicle. The findings were significant since they showed that friction time of use, a parameter neglected in RBS testing, plays an important part in the efficient operation of an EV. The overall results from the vehicle energy recovery modelling showed good agreement with the data from drive cycle testing and the model has potential to be further developed to gain greater insight into vehicle RBS braking behaviour for EVs in general.

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Sudadiyo, Sri, and Geni Rina Sunaryo. "THERMODYNAMICS ANALYSES ON REGENERATIVE STEAM CYCLE WITH TWO TANKS FOR HTGR-10 CONCEPT." GANENDRA Majalah IPTEK Nuklir 20, no. 2 (2017): 73. http://dx.doi.org/10.17146/gnd.2017.20.2.3302.

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THERMODYNAMICS ANALYSES ON REGENERATIVE STEAM CYCLE WITH TWO TANKS FOR HTGR-10 CONCEPT. In this work, steam cycle from a nuclear power plant is explored in order to increase electric power efficiency and output. A thermal source in the form of a HTGR-10 concept is considered. The power conversion unit of HTGR-10 consists of steam generators, turbines, condensers, pumps , and connecting pipes. Helium is used as the core coolant and the working fluid for power conversion unit is water/steam. The proposed thermodynamic process modification has been evaluated for regenerative steam power cycle of this reactor. The scope of study covered regenerative steam cycle with two tanks including feed water tank and intermediate feed water tank. The evaluation analyzes the effect of pressure, efficiencies of turbine and pumps, and tanks against thermal efficiency. The Cycle-Tempo software is used to simulate and optimize those effects on steam cycle based on HTGR-10. The results indicate improvements of as much as 2.65 % in thermal efficiency and 0.271 MWe in electric power.

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Yang, Hui Shan, Jin Mei Wu, Li Shuang Wu, and Zhi Wei Wu. "Thermoeconomic Optimization for a Ferroelectric Stirling Refrigeration-Cycle." Applied Mechanics and Materials 700 (December 2014): 175–78. http://dx.doi.org/10.4028/www.scientific.net/amm.700.175.

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Using the finite-time thermodynamics, an irreversible cycle model of the Stirling refrigeration-cycle, using a ferroelectric material as the working substance, is established. Several irreversibilities due to thermal resistances between the working substance and the heat reservoirs, regenerative losses in two regenerative processes are taken into account. The influence of these irreversible losses on the performance of the ferroelectric Stirling refrigeration-cycleis analyzed. The thermoeconomic optimization for ferroelectric Stirling refrigeration-cycle is reported. The cooling load for the refrigerator per unit total cost is proposed as objective functions for the optimization. The optimum performance parameters which maximize the objective functions are investigated. Since the optimization technique consists of both investment and energy consumption costs, the obtained results are more general and realistic.

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Qin, Jiang, Wen Bao, Silong Zhang, and Weixing Zhou. "Comparison During a Scramjet Regenerative Cooling and Recooling Cycle." Journal of Thermophysics and Heat Transfer 26, no. 4 (2012): 612–18. http://dx.doi.org/10.2514/1.t3820.

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Journal articles on the topic 'Regenerative cycle'

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