scholarly journals A View from the Conservation of Energy to Chemical Thermodynamic

Author(s):  
Ahmet Gurses ◽  
Mehtap Ejder-Korucu
1997 ◽  
Vol 161 ◽  
pp. 437-442
Author(s):  
Salvatore Di Bernardo ◽  
Romana Fato ◽  
Giorgio Lenaz

AbstractOne of the peculiar aspects of living systems is the production and conservation of energy. This aspect is provided by specialized organelles, such as the mitochondria and chloroplasts, in developed living organisms. In primordial systems lacking specialized enzymatic complexes the energy supply was probably bound to the generation and maintenance of an asymmetric distribution of charged molecules in compartmentalized systems. On the basis of experimental evidence, we suggest that lipophilic quinones were involved in the generation of this asymmetrical distribution of charges through vectorial redox reactions across lipid membranes.


2011 ◽  
Vol 19 (2) ◽  
pp. 159 ◽  
Author(s):  
Jaime Wisniak

Los conceptos de masa, movimiento y energía han ocupado la atención de filósofos y científicos desde tiempos ancestrales. Aun cuando hubo muchos que creían que la masa y la energía se conservaban, debieron pasar muchos años hasta que la primera ley de la termodinámica adquiriera su forma actual. La ley de conservación de la energía es uno de los principios fundamentales del mundo físico como lo entendemos hoy. Negar la posibilidad del movimiento perpetuo le coloca un límite superior a la utilización de la energía y a la eficiencia termodinámica de un proceso.


2021 ◽  
pp. 073490412199344
Author(s):  
Wolfram Jahn ◽  
Frane Sazunic ◽  
Carlos Sing-Long

Synthesising data from fire scenarios using fire simulations requires iterative running of these simulations. For real-time synthesising, faster-than-real-time simulations are thus necessary. In this article, different model types are assessed according to their complexity to determine the trade-off between the accuracy of the output and the required computing time. A threshold grid size for real-time computational fluid dynamic simulations is identified, and the implications of simplifying existing field fire models by turning off sub-models are assessed. In addition, a temperature correction for two zone models based on the conservation of energy of the hot layer is introduced, to account for spatial variations of temperature in the near field of the fire. The main conclusions are that real-time fire simulations with spatial resolution are possible and that it is not necessary to solve all fine-scale physics to reproduce temperature measurements accurately. There remains, however, a gap in performance between computational fluid dynamic models and zone models that must be explored to achieve faster-than-real-time fire simulations.


2011 ◽  
Vol 347-353 ◽  
pp. 2811-2814
Author(s):  
Nan Zhu ◽  
Bao Ming Li

Low-carbon economy is a new path which our country is taking to develop economy. As one of the provinces in the southeast coast of China, Fujian develop a low-carbon economy directly relating to the transformation of its economic growth, conservation of energy, improvement of productivity, innovation of technology and so on. We can say that the development of low-carbon economy directly affects the sustainable development of economy and society in Fujian province of China. Therefore, firstly, we believe that government and enterprise should optimize the allocation of resource and improve the utilization of resource. Secondly, the tax policies are supposed to adjust to stimulate the development of environmental protection industry. Thirdly, government should accelerate the construction of infrastructures. Fourthly, the legal system needs to be built and perfected so as to promote the development of low-carbon economy. At last, the investment of techniques is supposed to increase to a certain degree, and the ability of innovation and management of enterprises should be promoted to adapt the development of low-carbon economy of Fujian province.


Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5270
Author(s):  
Zhenbo Yuan ◽  
Xuanzhong Liu ◽  
Changmei Liu ◽  
Yan Zhang ◽  
Yijian Rao

Non-proteinogenic amino acids have attracted tremendous interest for their essential applications in the realm of biology and chemistry. Recently, rising C–H functionalization has been considered an alternative powerful method for the direct synthesis of non-proteinogenic amino acids. Meanwhile, photochemistry has become popular for its predominant advantages of mild conditions and conservation of energy. Therefore, C–H functionalization and photochemistry have been merged to synthesize diverse non-proteinogenic amino acids in a mild and environmentally friendly way. In this review, the recent developments in the photo-mediated C–H functionalization of proteinogenic amino acids derivatives for the rapid synthesis of versatile non-proteinogenic amino acids are presented. Moreover, postulated mechanisms are also described wherever needed.


2006 ◽  
Vol 290 (2) ◽  
pp. H894-H903 ◽  
Author(s):  
Ghassan S. Kassab

The branching pattern and vascular geometry of biological tree structure are complex. Here we show that the design of all vascular trees for which there exist morphometric data in the literature (e.g., coronary, pulmonary; vessels of various skeletal muscles, mesentery, omentum, and conjunctiva) obeys a set of scaling laws that are based on the hypothesis that the cost of construction of the tree structure and operation of fluid conduction is minimized. The laws consist of scaling relationships between 1) length and vascular volume of the tree, 2) lumen diameter and blood flow rate in each branch, and 3) diameter and length of vessel branches. The exponent of the diameter-flow rate relation is not necessarily equal to 3.0 as required by Murray's law but depends on the ratio of metabolic to viscous power dissipation of the tree of interest. The major significance of the present analysis is to show that the design of various vascular trees of different organs and species can be deduced on the basis of the minimum energy hypothesis and conservation of energy under steady-state conditions. The present study reveals the similarity of nature's scaling laws that dictate the design of various vascular trees and the underlying physical and physiological principles.


2007 ◽  
Vol 135 (11) ◽  
pp. 3876-3894 ◽  
Author(s):  
Ali R. Mohebalhojeh ◽  
David G. Dritschel

Abstract The representation of nonlinear shallow-water flows poses severe challenges for numerical modeling. The use of contour advection with contour surgery for potential vorticity (PV) within the contour-advective semi-Lagrangian (CASL) algorithm makes it possible to handle near-discontinuous distributions of PV with an accuracy beyond what is accessible to conventional algorithms used in numerical weather and climate prediction. The emergence of complex distributions of the materially conserved quantity PV, in the absence of forcing and dissipation, results from large-scale shearing and deformation and is a common feature of high Reynolds number flows in the atmosphere and oceans away from boundary layers. The near-discontinuous PV in CASL sets a limit on the actual numerical accuracy of the Eulerian, grid-based part of CASL. For the spherical shallow-water equations, the limit is studied by comparing the accuracy of CASL algorithms with second-order-centered, fourth-order-compact, and sixth-order-supercompact finite differencing in latitude in conjunction with a spectral treatment in longitude. The comparison is carried out on an unstable midlatitude jet at order one Rossby number and low Froude number that evolves into complex vortical structures with sharp gradients of PV. Quantitative measures of global conservation of energy and angular momentum, and of imbalance as diagnosed using PV inversion by means of Bolin–Charney balance, indicate that fourth-order differencing attains the highest numerical accuracy achievable for such nonlinear, advectively dominated flows.


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