scholarly journals Fast energy minimization method for surface‐related‐multiple removal

1994 ◽  
Author(s):  
Roald G. van Borselen ◽  
Jacob T. Fokkema ◽  
P. M. van den Berg ◽  
Raphic M. van der Weiden ◽  
Tik Hing Tan
Keyword(s):  
Energy Minimization ◽  
Minimization Method ◽  
Energy Minimization Method

Extraction of the Coefficient of Thermal Expansion of Thin Films from Buckled Membranes

1998 ◽  
Vol 546 ◽  
Author(s):  
V. Ziebartl ◽  
O. Paul ◽  
H. Baltes
Keyword(s):  
Thin Films ◽  
Finite Element ◽  
Thermal Expansion ◽  
Silicon Nitride ◽  
Excellent Agreement ◽  
Energy Minimization ◽  
Coefficient Of Thermal Expansion ◽  
Temperature Dependent ◽  
Minimization Method ◽  
Energy Minimization Method

AbstractWe report a new method to measure the temperature-dependent coefficient of thermal expansion α(T) of thin films. The method exploits the temperature dependent buckling of clamped square plates. This buckling was investigated numerically using an energy minimization method and finite element simulations. Both approaches show excellent agreement even far away from simple critical buckling. The numerical results were used to extract Cα(T) = α0+α1(T−T0 ) of PECVD silicon nitride between 20° and 140°C with α0 = (1.803±0.006)×10−6°C−1, α1 = (7.5±0.5)×10−9 °C−2, and T0 = 25°C.

Gibbs Energy Minimization Method for Analysis of Methane Oxidation to Higher Hydrocarbons

2012 ◽  
Author(s):  
Nor Aishah Saidina Amin ◽  
Ee Peng Soon
Keyword(s):  
Gibbs Energy ◽  
Methane Oxidation ◽  
Energy Minimization ◽  
Methane Conversion ◽  
Minimization Method ◽  
Gibbs Energy Minimization ◽  
System Pressure ◽  
Conversion Of Methane ◽  
Higher Hydrocarbons ◽  
Energy Minimization Method

Kaedah peminimuman jumlah tenaga Gibbs sangat berguna untuk menganalisis kemungkinan penukaran metana kepada hidrokarbon dan syngas pada suhu dan tekanan tertentu secara teoritikal. Keputusan numerik menunjukkan penukaran metana meningkat dengan peningkatan kepekatan oksigen dan suhu tindak balas. Bagaimanapun, kehadiran oksigen merencat pembentukan hidrokarbon tinggi yang kebanyakannya mengandungi aromatik, tetapi menggalakkan pembentukan hidrogen. Apabila tekanan sistem bertambah, hasil aromatik, olefin dan hidrogen berkurang, tetapi hasil parafin meningkat. Karbon monoksida menjadi produk mengandungi oksigen yang utama daripada pengoksidaan metana sementara hampir tiada H2O, CH3OH and HCOH yang dikesan walaupun sejumlah kecil karbon dioksida terbentuk pada suhu yang agak rendah dan tekanan tinggi. Kata kunci: Keseimbangan kimia termodinamik, peminimuman jumlah tenaga Gibbs, penukaran metana, hidrokarbon tinggi The total Gibbs energy minimization method is useful to theoretically analyze the feasibility of methane conversion to higher hydrocarbons and syngas at the selected temperature and pressure. Numerical results showed that the conversion of methane increased with oxygen concentration and reaction temperature, but decreased with pressure. Nevertheless, the presence of oxygen suppressed the formation of higher hydrocarbons that mostly consisted of aromatics, but enhanced the formation of hydrogen. As the system pressure increased, the aromatics, olefins and hydrogen yields diminished, but the paraffin yield improved. Carbon monoxide seemed to be the major oxygen-containing equilibrium product from methane oxidation whilst almost no H2O, CH3OH and HCOH were detected although traces amount of carbon dioxide were formed at relatively lower emperature and higher pressure. Key words: Thermodynamic chemical equilibrium, Gibbs energy minimization, methane conversion, higher hydrocarbons

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