scholarly journals Thermal Stability of Potassium-Promoted Cobalt Molybdenum Nitride Catalysts for Ammonia Synthesis

Catalysts ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 100
Author(s):  
Paweł Adamski ◽  
Wojciech Czerwonko ◽  
Dariusz Moszyński
Keyword(s):  
Thermal Stability ◽  
Alkali Metals ◽  
Ammonia Synthesis ◽  
Stability Test ◽  
Molybdenum Nitride ◽  
Molybdenum Nitrides ◽  
Cobalt Molybdenum Nitride ◽  
Synthesis Catalysts ◽  
Two Phases ◽  
The Stability

The application of cobalt molybdenum nitrides as ammonia synthesis catalysts requires further development of the optimal promoter system, which enhances not only the activity but also the stability of the catalysts. To do so, elucidating the influence of the addition of alkali metals on the structural properties of the catalysts is essential. In this study, potassium-promoted cobalt molybdenum nitrides were synthesized by impregnation of the precursor CoMoO4·3/4H2O with aqueous KNO3 solution followed by ammonolysis. The catalysts were characterized with the use of XRD and BET methods, under two conditions: as obtained and after the thermal stability test. The catalytic activity in the synthesis of ammonia was examined at 450 °C, under 10 MPa. The thermal stability test was carried out by heating at 650 °C in the same apparatus. As a result of ammonolysis, mixtures of two phases: Co3Mo3N and Co2Mo3N were obtained. The phase concentrations were affected by potassium admixture. The catalytical activity increased for the most active catalyst by approximately 50% compared to non-promoted cobalt molybdenum nitrides. The thermal stability test resulted in a loss of activity, on average, of 30%. Deactivation was caused by the collapse of the porous structure, which is attributed to the conversion of the Co2Mo3N phase to the Co3Mo3N phase.

Effect of potassium precursors on the thermal stability of K-promoted Ru/carbon catalysts for ammonia synthesis

2015 ◽  
Vol 5 (5) ◽  
pp. 2829-2838 ◽  
Author(s):  
Bingyu Lin ◽  
Yanchao Qi ◽  
Yunjie Guo ◽  
Jianxin Lin ◽  
Jun Ni
Keyword(s):  
Thermal Stability ◽  
Ammonia Synthesis ◽  
The Stability ◽  
Carbon Catalysts ◽  
Thermal Stability Of

The effect of K precursors on the stability of K-promoted Ru/carbon catalysts for ammonia synthesis was studied.

scholarly journals Thermal stability of catalyst for ammonia synthesis based on cobalt molybdenum nitrides

2018 ◽  
Vol 73 (4) ◽  
pp. 851-859 ◽  
Author(s):  
Paweł Adamski ◽  
Dariusz Moszyński ◽  
Marlena Nadziejko ◽  
Agata Komorowska ◽  
Adam Sarnecki ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ammonia Synthesis ◽  
Molybdenum Nitrides ◽  
Thermal Stability Of

scholarly journals Research on Suppression Method of Power Noise in the Stability Test Device

2021 ◽  
Vol 645 ◽  
pp. 012027
Author(s):  
Junhao Huang ◽  
Fang Fang ◽  
Zhihua Wang ◽  
Mingxuan Hang ◽  
Yibo Wang ◽  
...  
Keyword(s):  
Stability Test ◽  
Test Device ◽  
Suppression Method ◽  
Power Noise ◽  
The Stability

Optimization of Organic Fibres%[Kevlar/Arobocel/Acrylic] in NAO Brake Pad Application and its Effect on Thermal Stability & Friction Characteristics

2012 ◽  
Vol 531-532 ◽  
pp. 8-12
Author(s):  
M.A. Sai Balaji ◽  
K. Kalaichelvan
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Minimum Weight ◽  
Friction Material ◽  
Brake Pad ◽  
Temperature Zone ◽  
Good Thermal Stability ◽  
Friction Testing ◽  
Brake Application ◽  
The Stability

Organic fibres (Kevlar/ Arbocel / Acrylic) have good thermal stability, higher surface area and bulk density. The optimization of organic fibres percentage for thermal behaviour is considered using TGA. The temperature raise during brake application will be between 150-4000 C and this temperature zone is very critical to determine the fade characteristics during friction testing. Hence, three different friction composites are developed with the same formulation varying only the Kevlar, Arbocel and Acrylic fibres which are compensated by the inert filler namely the barites and are designated as NA01, NA02 and NA03 respectively. After the fabrication, the TGA test reveals that the composite NA03 has minimum weight loss. The friction coefficient test rig is then used to test the friction material as per SAE J661a standards. The results prove that the brake pad with minimum weight loss during TGA has higher friction stability. Thus, we can correlate the thermal stability with the stability of friction.

Thermal stability test and analysis of a 20-actuator bimorph deformable mirror

2009 ◽  
Vol 18 (3) ◽  
pp. 1089-1095 ◽  
Author(s):  
Ning Yu ◽  
Zhou Hong ◽  
Yu Hao ◽  
Rao Chang-Hui ◽  
Jiang Wen-Han
Keyword(s):  
Thermal Stability ◽  
Stability Test ◽  
Deformable Mirror

scholarly journals Stability and Compatibility Aspects of Drugs: The Case of Selected Cephalosporins

Antibiotics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 549
Author(s):  
Szymon Tomczak ◽  
Aleksandra Gostyńska ◽  
Malwina Nadolna ◽  
Karolina Reisner ◽  
Marta Orlando ◽  
...  
Keyword(s):  
Parenteral Nutrition ◽  
Treatment Failure ◽  
Medical Errors ◽  
Stability Test ◽  
Intravenous Drug ◽  
Common Cause ◽  
Life Threatening ◽  
Degradation Studies ◽  
The Stability ◽  
Infusion Fluids

Intravenous drug incompatibilities are a common cause of medical errors, contributing to ineffective therapy and even life-threatening events. The co-administration of drugs must always be supported by studies confirming compatibility and thus guarantee the therapy’s safety. Particular attention should be paid to the possible incompatibilities or degradation of intravenous cephalosporins in different infusion regimens since the administration of drugs with inadequate quality may cause treatment failure. Therefore, an appropriate stability test should be performed. The study aimed to present various aspects of the stability and compatibility of five cephalosporins: cefepime (CFE), cefuroxime (CFU), ceftriaxone (CFX), ceftazidime (CFZ), and cefazoline (CFL). The degradation studies in parenteral infusion fluids and PN admixtures were conducted for CFE and CFU. The interactions between CFX or CFZ and PN admixtures, as well as the compatibility of CFL with five commercial parenteral nutrition (PN) admixtures, were investigated. The content of CFX and CFZ in PN admixture after 24 h was >90%. CFL administered simultaneously with PN admixture by the same infusion set using Y-site was compatible only with Nutriflex Lipid Special. CFE and CFU were stable in all tested infusion fluids for a minimum of 48 h and decomposed in PN admixtures during storage.

Intrinsic Thermal Stability of Anisotropic Thin-Film Superconductors

1990 ◽  
Vol 112 (1) ◽  
pp. 10-15 ◽  
Author(s):  
M. I. Flik ◽  
C. L. Tien
Keyword(s):  
Thin Film ◽  
Thermal Stability ◽  
Stability Criterion ◽  
High Temperature Superconductors ◽  
Stability Criteria ◽  
Anisotropic Thermal Conductivity ◽  
Operating Current ◽  
Released Energy ◽  
The Stability ◽  
Thermal Stability Of

Intrinsic thermal stability denotes a situation where a superconductor can carry the operating current without resistance at all times after the occurrence of a localized release of thermal energy. This novel stability criterion is different from the cryogenic stability criteria for magnets and has particular relevance to thin-film superconductors. Crystals of ceramic high-temperature superconductors are likely to exhibit anisotropic thermal conductivity. The resultant anisotropy of highly oriented films of superconductors greatly influences their thermal stability. This work presents an analysis for the maximum operating current density that ensures intrinsic stability. The stability criterion depends on the amount of released energy, the Biot number, the aspect ratio, and the ratio of the thermal conductivities in the plane of the film and normal to it.

scholarly journals Thermal Stability of Residual Stresses in Differently Deep Rolled Surface Layers of Steel SAE 1045

2021 ◽  
Author(s):  
Stephanie Saalfeld ◽  
Thomas Wegener ◽  
Berthold Scholtes ◽  
Thomas Niendorf
Keyword(s):  
Thermal Stability ◽  
Elevated Temperature ◽  
Residual Stresses ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Decisive Role ◽  
Deep Rolling ◽  
Material Conditions ◽  
The Stability ◽  
Thermal Stability Of

AbstractThe stability of compressive residual stresses generated by deep rolling plays a decisive role on the fatigue behavior of specimens and components, respectively. In this regard, deep rolling at elevated temperature has proven to be very effective in stabilizing residual stresses when fatigue analysis is conducted at ambient temperature. However, since residual stresses can be affected not only by plastic deformation but also when thermal energy is provided, it is necessary to analyze the influence of temperature and time on the relaxation behavior of residual stresses at elevated temperature. To evaluate the effect of deep rolling at elevated temperatures on stability limits under thermal as well as combined thermo-mechanical loads, the present work introduces and discusses the results of investigations on the thermal stability of residual stresses in differently deep rolled material conditions of the steel SAE 1045.

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