1,646 research outputs found
Interview with Jean Francois Revel, author
No full textJean Francois Revel, the author of Without Marx or Jesus, has been quoted as saying, "The United States is now a microcosm for all of the problems man faces." In this interview with Meredith Watts, he discusses a new kind of revolution which could produce successful change without violent upheavalGrayscaleSoun
MINLP model and two-stage algorithm for the simultaneous synthesis of heat exchanger networks, utility systems and heat recovery cycles
No full textThis work proposes a novel approach for the simultaneous synthesis of Heat Exchanger Networks (HEN) and Utility Systems of chemical processes and energy systems. Given a set of hot and cold process streams and a set of available utility systems, the method determines the optimal selection, arrangement and design of utility systems and the heat exchanger network aiming to rigorously consider the trade-off between efficiency and capital costs. The mathematical formulation uses the SYNHEAT superstructure for the HEN, and ad hoc superstructures and nonlinear models to represent the utility systems. The challenging nonconvex MINLP is solved with a two-stage algorithm. A sequential synthesis algorithm is specifically developed to generate a good starting solution. The algorithm is tested on a literature test problem and two industrial problems, the optimization of the Heat Recovery Steam Cycle of a Natural Gas Combined Cycle and the heat recovery system of an Integrated Gasification Combined Cycle. (C) 2017 Elsevier Ltd. All rights reserved.SCI-STI-F
Synthesis of Heat Exchanger Networks and Utility Systems: sequential initialization procedure and simultaneous MINLP algorithm
No full textThis work presents an extended version of the method recently proposed by (Martelli et al. 2015) for the simultaneous synthesis of Heat Exchanger Networks (HEN) and Utility Systems. The algorithm simultaneously determines the optimal selection of utility systems, their design, as well as the heat exchanger network between process-process, process-utility and utility-utility streams that minimize the total annual cost. The algorithm exploits an ad hoc sequential approach to find a good starting solution for the challenging synthesis problem. The Mixed Integer NonLinear Programming (MINLP) problem related to the simultaneous synthesis problem is then tackled with a specifically developed two-stage algorithm in which the Variable Neighborhood Search optimizes the integer variables and the Sequential Quadratic Programming algorithm optimizes the real variables. The algorithm is tested on the optimization of the HEN and Heat Recovery Steam Cycle of an Integrated Gasification Combined Cycle featuring 27 streams (1664 binary variables)
Framework for the Multiperiod Sequential Synthesis of Heat Exchanger Networks with Selection, Design, and Scheduling of Multiple Utilities
No full textA novel sequential approach is proposed for the multiperiod synthesis of Heat Exchanger Networks (HEN) and Utility Systems of chemical processes and energy systems. The framework can be used also for single period problems. Given the set of hot and cold process streams with period dependent heat loads and target temperatures and a set of available utility systems, the algorithm determines the optimal utility system selection, design, and operation scheduling, as well as the optimal HEN. In this work, the approach of solving multiperiod problems by adopting (1) the Multiperiod Utility Integration and Scheduling model of Maréchal and Kalitventzeff, a modified formulation for (2) the Multiperiod Minimum Number of Units problem of Floudas and Grossmann, and (3) the Multiperiod Minimum Investment Network problem proposed by Floudas and Grossmann is improved by coupling the existing framework with the derivative-free hybrid algorithm PGS-COM of Martelli and Amaldi. Compared to the classic sequential approach,3 it is possible to select, design, and determine the optimal operation scheduling (switching on/off) of the utility systems, to design the HEN considering not only parallel configuration of utilities but also series of utility exchangers and hybrids configurations, to optimize the matches between streams looking for the minimum total cost rather than only for the minimum number of units, and to account for nonlinear cost functions not related to heat exchangers area. The proposed framework is tested on small-scale and medium-scale case studies in order to make a comparison with the classic sequential approach.SCI-STI-F
Voyages de Pythagore en Egypte, dans le Chaldée, dans l'Inde, en Crete, a Sparte ... : suivis de ses lois politiques et morales : tome sixieme.
No full textSegun Brunet, T. III num. 22715, el autor es Sylvain MarechalSign.: [ ]\p2\s, A-Z\p8\s, 2A-2G\p8\s, 2H\p7\sAntepLa h. de grab. calc. encarada con la port. representa a Pitágoras: "Dumbrum scull.
Beauregard House
No full textGeneral view; The architect Francois Correjolles, whose creole French family emigrated from St. Domingue (Haiti), added new American Federal elements while preserving some of the traditional creole plan. The Beauregard-Keyes House, built in 1826 for wealthy auctioneer Joseph Le Carpentier, is a fine example of a raised, center-hall house. It is named for two of its former tenants, Confederate General Pierre Gustave Toutant (P.G.T.) Beauregard and author Frances Parkinson Keyes. General Beauregard lived in the home from 1866 to 1868 while he was president of the New Orleans, Jackson, and Great Northern Railroad. The home features twin curved staircases, leading to a Tuscan portico. The garden's design duplicates the original 1865 plans. (Common Routes: St. Domingue-Louisiana exhibition, 2006) Source: Historic New Orleans Collection [website]; http://www.hnoc.org/ (accessed 1/24/2008
Alien theory : the decline of materialism in the name of matter
No full textThe thesis tries to define and explain the rudiments of a 'nonphilosophical'
or 'non-decisional' theory of materialism on the basis of a
theoretical framework provided by the 'non-philosophy' of Francois
Laruelle. Neither anti-philosophical nor anti-materialist in character, non-materialism
tries to construct a rigorously transcendental theory of matter by
using certain instances of philosophical materialism as its source material.
The materialist decision to identify the real with matter is seen to retain a
structural isomorphy with the phenomenological decision to identify the real
with the phenomenon. Both decisions are shown to operate on the basis of a
methodological idealism; materialism on account of its confusion of matter
and concept; phenomenology by virtue of its confusion of phenomenon and
logos. By dissolving the respectively 'materiological' and
'phenomenological' amlphibolies which are the result of the failure to effect a
rigorously transcendental separation between matter and concept on the one
hand; and between phenomenon and logos on the other, non-materialist
theory proposes to mobilise the non-hybrid or non-decisional concepts of a
'matter-without-concept' and of a 'phenomenon-without-logos' in order to
effect a unified but non-unitary theory of phenomenology and materialism.
The result is a materialisation of thinking that operates according to matter's
foreclosure to decision. That is to say, a transcendental theory of the
phenomenon that licenses limitless phenomenological plasticity,
unconstrained by the apparatus of eidetic intuition or any horizon of
apophantic disclosure; yet one which is simultaneously a transcendental
theory of matter, uncontaminated by the bounds of empirical perception and
free of all phenomenological circumscription
MINLP Model and Two-level Algorithm for the Simultaneous Synthesis of Heat Exchanger Networks and Utility Systems
No full textThis work proposes a novel approach for the simultaneous synthesis of Heat Exchanger Networks (HEN) and Utility Systems. Given a set of hot and cold process streams and a set of available utility systems (e.g., gas turbine, steam cycle, boiler, etc), the method determines the optimal selection of utility systems, their arrangement and design (including steam generator), and the heat exchanger network (between process-process as well as process-utility and utility-utility streams) rigorously considering the trade-off between efficiency and capital costs. The mathematical model is formulated as a Mixed Integer NonLinear Program (MINLP) and it combines the SYNHEAT superstructure for HENs with ad hoc models/superstructures for utility systems. The challenging MINLP is solved with a two-level algorithm using at the upper level the Variable Neighbourhood Search (VNS) algorithm to optimize the integer variables, and at the lower level the SQP algorithm to optimize the real variables. The algorithm is tested on problems with up to 15 streams (corresponding to 465 binary variables).SCI-STI-F
3D design and optimization of heat exchanger network for solid oxide fuel cell-gas turbine in hybrid electric vehicles
No full textThe development of electric vehicles is considered as one of the sustainable way in the automotive industry to reduce greenhouse gases emissions and to allow transportation sector to comply with environmental targets required in present and future years. Due to the limited range of autonomy of the electric vehicles and the induced cost and environmental impacts of large capacity batteries, hybrid electric vehicles have been deeply investigated and developed over the last years. In this study, a Solid Oxide Fuel Cell combined with Gas Turbines (SOFC-GT) is used as a range extender in hybrid electric vehicle. The SOFC-GT system increases the autonomy of the electric vehicle and has high electric efficiency of 77%. In this work, the Heat Exchanger Network (HEN) to recover thermal energy in the SOFC-GT system has been studied. The HEN has to meet the targets of limited volume and mass to be compatible with the installation on the hybrid vehicle. This study is basically divided into three steps. In the first step, the HEN synthesis is performed with a mathematical model developed in AMPL, stating the optimal matches between hot and cold streams. In the second step, a model is developed to size the heat exchangers with the LMTD method. In the final step, an optimization problem is solved to minimize the volume or mass of the HEN, by sizing the heat exchangers with a global view of HEN, considering their assembly in a limited space and defining the paths of flow streams. Finally, some heat exchangers have been printed using plastic with a SLA 3D printer, with presentation purpos
A general superstructure for the optimal synthesis and design of power and inverse Rankine cycles
No full textThis work presents a very general superstructure capable of reproducing any configuration of Rankine cycles, both power cycles (steam cycles we well as Organic Rankine Cycles) and inverse cycles (refrigeration cycles or heat pumps), as well as heat/steam distribution networks. The model is included in a simultaneous utility + Heat Exchanger Network (HEN) optimization method and used to optimize the design and the HEN of a steam cycle, a heat recovery Organic Rankine Cycles and a heat pump
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