Mixing between chemically variable primitive basalts creates and modifies crystal cargoes

Basaltic crystal cargoes often preserve records of mantle-derived chemical variability that have been erased from their carrier liquids by magma mixing. However, the consequences of mixing between similarly primitive but otherwise chemically variable magmas remain poorly understood despite ubiquitous evidence of chemical variability in primary melt compositions and mixing-induced disequilibrium within erupted crystal cargoes. Here we report observations from magma–magma reaction experiments performed on analogues of primitive Icelandic lavas derived from distinct mantle sources to determine how their crystal cargoes respond to mixing-induced chemical disequilibrium. Chemical variability in our experimental products is controlled dominantly by major element diffusion in the melt that alters phase equilibria and triggers plagioclase resorption within regions that were initially plagioclase saturated. Isothermal mixing between chemically variable basaltic magmas may therefore play important but previously underappreciated roles in creating and modifying crystal cargoes by unlocking plagioclase-rich mushes and driving resorption, (re-)crystallisation and solid-state diffusion.

KARAKTERISTIK FLUIDA PEMBAWA MINERALISASI PIT RAMBA JORING DEPOSIT MARTABE, SUMATRA UTARA

Penelitian ini bertujuan untuk mengetahui evolusi hidrotermal dari fluida pembawa mineralisasi yang terdapat di Pit Ramba Joring, meliputi temperatur, tekanan, densitas dan kedalaman pembentukan mineralisasi. Penelitian ini menggunakan analisis inklusi fluida. Sampel yang dianalisis merupakan sampel yang terindikasi terbentuk bersamaan dengan mineralisasi bijih (syngenetik), pada dua tekstur utama bijih yaitu batuan dengan tekstur silica vuggy yang terbentuk pada kisaran Th 331ºC hingga 394ºC, Tm -15,19ºC hingga -12,94ºC dengan salinitas 14,42 wt% hingga 14,89 wt%. NaCl equivalent dan batuan dengan tekstur brecciated terbentuk pada kisaran Th 287,8°C hingga 398,2°C, Tm -14,89°C hingga -11,76ºC serta salinitas 13,91 wt% hingga 4,87 wt%. NaCl equivalent. Korelasi positif antara temperatur homogenisasi pembentukan mineralisasi dengan salinitas larutan menandakan bahwa proses leaching yang membentuk rongga pada batuan terjadi pada stage awal proses alterasi hidrotermal yang diawali dengan proses leaching membentuk rongga (vuggy silica) yang diikuti proses silisifikasi dengan tekstur brecciated, pada fase ini berlangsung pengendapan mineralisasi. Asal larutan yang menjadi larutan pembentuk endapan hidrotermal merupakan jenis larutan basinal water-seawater dalam bentuk connate water yang masih dipengaruhi oleh air permukaan/meteoric water yang menunjukkan adanya indikasi hubungan dengan magmatic water. Densitas fluida pembentuk bijih logam berkisar pada 0,8 gr/cm3 sampai dengan 0,9 gr/cm3 sedangkan proses pembentukan bijih pada Pit Ramba Joring termasuk dalam isothermal mixing dengan sedikit pengaruh pemanasan/boiling.

Globally Optimal Synthesis of Heat Exchanger Networks.Part III:Non-isothermal Mixing in Minimal and Non-Minimal Networks

In this work, the enumeration algorithms presented in parts I and II for the globally optimal synthesis of heat exchanger networks are extended to consider non-isothermal mixing. The previous models are modified by adding non-isothermal mixing constraints and new models are constructed to target the bounds of the energy consumption and the binding exchanger minimum approximation temperature. These new models are solved using algorithms that involve solving the solution of systems of equations instead of mathematical programming. We also present two alternatives for optimizing each enumerated structure, namely, the use of a global solver, or the use of a golden search with simple resolution of non-isothermal mixing model for fixed energy consumption. The non-isothermal mixing model is reformulated as a convex model, either solved using nonlinear programming or a programming-free methodology, i.e. solving Karush-Kuhn-Tucker equations. A global optimum search algorithm is developed and examples are tested comparing the proposed strategies.

APPLICATION OF THE POSTULATE OF NONEQUILIBRIUM TO CALCULATE THE NONEQUILIBRIUM OF SYSTEMS OF DISSIMILAR GASES AND LIQUIDS

The postulate of nonequilibrium is at the heart of the second law of thermodynamics. According to this postulate, there is a real property of matter – “nonequilibrium,” which characterizes the uneven distribution of matter and motion in space. All processes (reversible and irreversible) can occur only in nonequilibrium systems. As a quantitative characteristic of the nonequilibrium of the system, the maximum work that can be performed during the transition of the nonequilibrium system to the equilibrium state is considered. The only formulation of the second law is given. When real (irreversible) processes occur, the nonequilibrium of the isolated system decreases, and in reversible processes, the nonequilibrium in the system of locally equilibrium subsystems does not change (the increment of one kind of the nonequilibrium entirely compensated by a decrease in the disequilibrium of some other kind). When the system reaches an equilibrium state, the disequilibrium disappears, and all processes cease. The article provides a calculated confirmation of the theoretical provisions of the concept of nonequilibrium and its mathematical apparatus by examples of determining the loss of the nonequilibrium of system when an isothermal mixing of dissimilar gases, and changes of nonequilibrium of system "pure solvent – solution" in the transition of part of the solvent in the solution. The mixing of the same gases leads to the Gibbs paradox, which is also considered in this paper. The concept of nonequilibrium was developed and the quantitative characteristics (measures) of nonequilibrium of the system were introduced allow to study nonequilibrium systems consisting of locally equilibrium subsystems in the sections of classical thermodynamics as simply as individual equilibrium systems.