Fertilizers

1999 ◽  
Author(s):  
Robert F. Keefer
Keyword(s):  
Ammonium Nitrate ◽  
Liquid Ammonia ◽  
Iron Catalyst ◽  
Hydrogen Gas ◽  
Nitrogen Gas ◽  
Ammonia Gas ◽  
Synthetic Process ◽  
Fe Catalyst ◽  
Complete Fertilizer ◽  
P Fertilizers

Fertilizers for soil on which plants grow come in a variety of forms, such as organic, inorganic, single nutrient, double nutrient, complete fertilizer (contains N, P, and K in that order), speciality fertilizers, composts, and manures. Information about each of these forms follows. Most of the N used in fertilizers is derived from a synthetic process developed by Europeans called the “Claude-Haber process.” This process uses nitrogen gas (N2) from the atmosphere along with hydrogen gas (H2) from natural gas in a device where pressure can be increased and temperature can be raised. The reaction is accelerated using an iron catalyst and removing the product (NH3) as it is formed. The Fe catalyst is subject to poisoning from impurities, such as As, Co, P, or S. Anhydrous ammonia has the highest percentage of N and the cheapest per unit of N since no processing is involved. Anhydrous (without water) ammonia is a gas but when compressed changes to a liquid. For application to soils a pressurized tank is required with a device to inject the liquid ammonia into the soil. Upon release of pressure, the liquid changes back to a gas; however, the ammonia gas reacts with the moisture in the soil to form NH4+ that is available for plants. One problem with ammonia is that NH3 gas is toxic to seedlings and growing plants, so must be applied prior to planting. This limits its use for landscape projects. Salt solutions of aqua ammonia are obtained by dissolving ammonia gas, ammonium nitrate, or urea in water. The amount dissolved will vary the concentration of N in the final product. This can be used in landscape projects, but care must be used as this material can salt out and plug up orifices when sprayed onto a soil. There is no real difference between liquid or solid fertilizers, provided the percentage of N is the same. Ammonia Nitrate [NH4NO3] (33.5% N) Ammonium nitrate is formed by ammonia gas reacting with nitric acid: . . . NH3 + HNO3 → NH4NO3 . . . This material is hygroscopic (absorbs water from the air) and requires moisture-proof bags for storage.

Effects of Gaseous Hydrogen on Fatigue Crack Growth Behavior of Low Carbon Steel

2009 ◽  
Author(s):  
Dongsun Lee ◽  
Hide-aki Nishikawa ◽  
Yasuji Oda ◽  
Hiroshi Noguchi
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Ductile Fracture ◽  
Crack Growth ◽  
Strain Range ◽  
Hydrogen Gas ◽  
Crack Growth Behavior ◽  
Low Carbon ◽  
Nitrogen Gas

In order to investigate the effects of hydrogen on the fatigue crack growth behavior of low carbon steel JIS S10C, bending fatigue tests were carried out using a specimen with a small blind artificial hole in a low pressure pure hydrogen gas atmosphere. The results show that the fatigue crack growth rate in hydrogen gas is higher than that in nitrogen gas, moreover, the degree of acceleration is greater in the high strain range. In fractography, intergranular facets mixed with ductile fracture and quasi-cleavage fracture with brittle striations appear in a hydrogen gas environment, while only ductile fracture mainly appears in nitrogen gas. In the low growth rate range, many intergranular facets are seen on the ductile fracture surface, and in the higher growth rate range, quasi-cleavage facets increase as the growth rate increases. The growth rate of a small crack in nitrogen gas can be expressed by dl/dN ∝ Δεpnl in the wide range of applied total strain range Δεt. The same type equation is also satisfied in hydrogen gas, but in the narrow range roughly from Δεt = 0.25% to Δεt = 0.37%. The fracture surface in this range shows only intergranular facets and a ductile morphology, but no quasi-cleavage fracture. Although the crack growth mechanism in hydrogen is different from that in nitrogen, observation of the mechanism of intergranular facet formation shows a similarity to the mechanism in nitrogen in which the slip-off mechanism of crack growth is valid. The formation of intergranular facets is also closely related to the slip behavior influenced by hydrogen. This means that there exists a high possibility for the application of the small crack growth law inhydrogen to not only S10C, but also to other carbon steels in which the intergranular facet appears.

Improved Conformality of CVD Titanium Nitride Films

1998 ◽  
Vol 555 ◽  
Author(s):  
Xinye Liu ◽  
Yuan Z. LU ◽  
Roy G. Gordon
Keyword(s):  
Titanium Nitride ◽  
Atmospheric Pressure ◽  
Chemical Vapor ◽  
Nitrogen Gas ◽  
Silicon Dioxide Layer ◽  
Ammonia Gas ◽  
Tin Films ◽  
Step Coverage ◽  
Novel Approach ◽  
Sticking Coefficients

AbstractWe demonstrate a novel approach to improving the step coverage of thin films made by chemical vapor deposition (CVD). Titanium nitride (TiN) films were deposited by atmospheric pressure CVD using tetrakis(diethylamido)titanium vapor (TDEAT) and ammonia gas (NH3) carried in nitrogen gas. Trimethylamine (NMe3) gas was added during some of the depositions. The substrates were patterned silicon wafers having holes with aspect ratio of 3.5 through a silicon dioxide layer. We discovered that the step coverage was significantly increased for TiN films made with NMe3. At 320 °C, the step coverage was increased from 70% to nearly 100%. Within the range of deposition temperatures used in our study, 320 °C to 370 °C, the amount of improvement increased as the deposition temperature decreased. The trimethylamine did not increase the resistivity or the impurity levels in the films, but it did reduce the growth rate slightly. We suggest that the trimethylamine adsorbs onto the surface, temporarily blocking some of the sites on which growth could take place. Thus the effective sticking coefficients for the precursors are decreased, and the step coverage is increased.

A Case Study of a Cooling Pipe for a Pre-Cooler Used in a 70-MPa Hydrogen Station

2017 ◽  
Author(s):  
Saburo Okazaki ◽  
Hisao Matsunaga ◽  
Shigeru Hamada ◽  
Masami Nakamura ◽  
Hisatake Itoga ◽  
...  
Keyword(s):  
Base Metal ◽  
Weld Joint ◽  
Hydrogen Gas ◽  
Nitrogen Gas ◽  
Mechanical Joint ◽  
Joint Specimen ◽  
Cooling Pipe ◽  
Round Bar ◽  
Hydrogen Station

A case study was conducted on the cooling pipe of a precooler which had been used in a 70-MPa hydrogen station demonstration project. The cooling pipe consisted of a main pipe, a mechanical joint pipe and a mechanical joint. The main and mechanical joint pipes had been joined using TIG welding. Through chemical composition analysis, microstructure observation and Vickers hardness measurement, it was revealed that the main and mechanical joint pipes had been manufactured from SUS316L and that 316L was the filler metal used for TIG welding. Round-bar specimens were machined out of the main pipe in order to investigate the tensile properties of the base metal. On the other hand, both round-bar specimen without reinforcement and square-bar specimens with reinforcement were fabricated from the weld-joint. Using the three types of specimens, slow strain rate tensile tests were performed in 0.1 MPa nitrogen gas and in 115 MPa hydrogen gas at a temperature of −40 °C. Reduction of area (RA), φ, for the round base-metal specimen, the round weld-joint specimen and the square weld-joint specimen were respectively, 83.5 %, 71.3 % and 81.4 % in nitrogen gas, whereas the related values in hydrogen gas were 60.1 %, 61.3 % and 40.1 %. In other words, the RA for the three types of specimens was smaller in hydrogen gas than in nitrogen gas. Dimples were formed on the fracture surfaces of the three specimen types in nitrogen gas, whereas both dimples and quasi-cleavages were formed in hydrogen gas.

Ammonia-gas and liquid ammonia treatments of silk fabric

2006 ◽  
Vol 101 (5) ◽  
pp. 3487-3492 ◽  
Author(s):  
Myung Sun Lee ◽  
Muncheul Lee ◽  
Takako Tokuyama ◽  
Tomiji Wakida ◽  
Goichi Inoue ◽  
...  
Keyword(s):  
Liquid Ammonia ◽  
Silk Fabric ◽  
Ammonia Gas

LOW TEMPERATURE GROWTH OF ALIGNED CARBON NANOTUBES IN LARGE AREA

2002 ◽  
Vol 16 (06n07) ◽  
pp. 853-859 ◽  
Author(s):  
P. H. LIN ◽  
C. R. LIN ◽  
K. H. CHEN ◽  
L. C. CHEN
Keyword(s):  
Carbon Nanotubes ◽  
Low Temperature ◽  
Microwave Plasma ◽  
Iron Catalyst ◽  
Ion Beam ◽  
Hydrogen Plasma ◽  
Emission Measurement ◽  
Ion Beam Sputtering ◽  
Large Area ◽  
Fe Catalyst

We have synthesized well-aligned, uniform carbon nanotubes (CNTs) in large area at low temperature of 500°C using microwave plasma- enhanced chemical vapor deposition on silicon and Corning glass 7059. This is a two-step process in that ion beam sputtering deposition was used to deposit iron catalyst thin films and followed by hydrogen plasma pretreatment to form nano-size Fe particles before the CNTs growth at the second step. The thickness of Fe catalyst thin film was found to be the most important factor in the low temperature CNTs growth process. Systematic control of the length, diameter, and alignment of the CNTs has been achieved by changing the deposition parameters such us microwave power, pressure, temperature and the thickness of Fe catalyst. High resolution SEM and TEM were used to characterize the morphology and structure of the nanotubes. Field emission measurement showed a low turn on field (6.2 V/m) and high emission current density (0.1 mA/cm2 at 9 V/m) for the films grown at low temperature of 500°C.

Effects of External and Internal Hydrogen on Tensile Properties of Austenitic Stainless Steels Containing Additive Elements

2015 ◽  
Author(s):  
Hisatake Itoga ◽  
Hisao Matsunaga ◽  
Junichiro Yamabe ◽  
Saburo Matsuoka
Keyword(s):  
Stainless Steels ◽  
Room Temperature ◽  
Austenitic Stainless Steels ◽  
Hydrogen Gas ◽  
Nitrogen Gas ◽  
Material Compatibility ◽  
Internal Hydrogen ◽  
The Stability ◽  
Reduction Of Area ◽  
Nickel Equivalent

Effect of hydrogen on the slow strain rate tensile (SSRT) properties of five types of austenitic stainless steels, which contain small amounts of additive elements (e.g., nitrogen, niobium, vanadium and titanium), was studied. Some specimens were charged by exposing them to 100 MPa hydrogen gas at 543 K for 200 hours. The SSRT tests were carried out under various combinations of specimens and test atmospheres as follows: (i) non-charged specimens tested in air at room temperature (RT), (ii) non-charged specimens tested in 0.1 MPa nitrogen gas at 193 K, (iii) hydrogen-charged specimens tested in air at RT, (iv) hydrogen-charged specimens tested in 0.1 MPa nitrogen gas at 193 K, and (v) non-charged specimens tested in 115 MPa hydrogen gas at RT. In the tests without hydrogen (i.e., cases (i) and (ii)), the reduction of area (RA) was nearly constant in all the materials, regardless of test temperature. In contrast, in the tests of internal hydrogen (cases (iii) and (iv)), RA was much smaller at 193 K than at RT in all the materials. It was revealed that the susceptibility of the materials to hydrogen embrittlement (HE) can successfully be estimated in terms of the nickel equivalent, which represents the stability of austenite phase. The result suggested that the nickel equivalent can be used for evaluating the material compatibility of austenitic stainless steels for hydrogen service.

scholarly journals Chemical and Electrocatalytic Ammonia Oxidation by Ferrocene

2019 ◽  
Author(s):  
Mahdi Raghibi Boroujeni ◽  
Christine Greene ◽  
Jeffery A. Bertke ◽  
Timothy H. Warren
Keyword(s):  
Liquid Ammonia ◽  
Computational Analysis ◽  
Ammonia Oxidation ◽  
Nitrogen Gas ◽  
Simple Modification ◽  
Mechanistic Insight ◽  
Earth Abundant ◽  
Insight Into ◽  
Oxidation Of Ammonia

Recognizing the potential of ammonia to serve as a carbon-free fuel, we describe an electrocatalytic system for the oxidation of ammonia based on ferrocene (Cp<sub>2</sub>Fe), an inexpensive, robust catalyst utilizing Earth-abundant iron. Ferrocenium (Cp<sub>2</sub>Fe<sup>+</sup>), the 1-electron oxidized form of ferrocene, cleanly oxidizes ammonia to generate nitrogen gas (N<sub>2</sub>) and protons captured by excess ammonia as NH<sub>4</sub><sup>+ </sup>with electrons reducing ferrocenium to ferrocene. This process occurs under electrocatalytic conditions to generate N<sub>2 </sub>with sustained current. Simple modification of ferrocene through sulfonation allows for solubility in liquid ammonia to enable electrocatalysis in highly concentrated, energy dense solutions of ammonia. Kinetic and computational analysis provides mechanistic insight into the oxidation of ammonia by ferrocenium.

scholarly journals The Influence of Nitrogen versus Hydrogen Diluting Gas on the Compound Layer Phase Formation during Ammonia Gas Nitriding of Iron and Low Alloy Steel

2019 ◽  
Author(s):  
Virginia M. Osterman ◽  
Donald F. Jordan
Keyword(s):  
Compound Layer ◽  
Current Data ◽  
Hydrogen Gas ◽  
Low Alloy Steel ◽  
Ammonia Gas ◽  
Reference Guide ◽  
Gamma Prime ◽  
Gas Nitriding ◽  
Alloy Steels ◽  
Prime Phase

Abstract In many large industrial furnaces, atmospheric ammonia gas nitriding processes use nitrogen as the diluting gas for safety, economic, and environmental reasons. The widely published Lehrer diagram for ammonia/hydrogen gas nitriding of pure iron serves as a reference guide for selecting ammonia/gas mixtures for nitriding of alloy steels, though the diagram is not precise or accurate when the diluting gas is not hydrogen. Current data reveals that nitrogen shifts the Lehrer diagram phase boundaries to the left. This is pertinent to the topic when only the alpha (α) or gamma prime phase (Fe4N) is desired, not epsilon (Fe2-3N).

scholarly journals Verrucomicrobial methanotrophs: ecophysiology of metabolically versatile acidophiles

2021 ◽  
Author(s):  
Rob A Schmitz ◽  
Stijn H Peeters ◽  
Wouter Versantvoort ◽  
Nunzia Picone ◽  
Arjan Pol ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Ammonium Nitrogen ◽  
Hydrogen Gas ◽  
Nutrient Cycles ◽  
Nitrogen Gas ◽  
Important Group ◽  
The Past ◽  
Metabolic Versatility ◽  
Genomic Analyses ◽  
Physiological And Biochemical

ABSTRACT Methanotrophs are an important group of microorganisms that counteract methane emissions to the atmosphere. Methane-oxidising bacteria of the Alpha- and Gammaproteobacteria have been studied for over a century, while methanotrophs of the phylum Verrucomicrobia are a more recent discovery. Verrucomicrobial methanotrophs are extremophiles that live in very acidic geothermal ecosystems. Currently, more than a dozen strains have been isolated, belonging to the genera Methylacidiphilum and Methylacidimicrobium. Initially, these methanotrophs were thought to be metabolically confined. However, genomic analyses and physiological and biochemical experiments over the past years revealed that verrucomicrobial methanotrophs, as well as proteobacterial methanotrophs, are much more metabolically versatile than previously assumed. Several inorganic gases and other molecules present in acidic geothermal ecosystems can be utilised, such as methane, hydrogen gas, carbon dioxide, ammonium, nitrogen gas and perhaps also hydrogen sulfide. Verrucomicrobial methanotrophs could therefore represent key players in multiple volcanic nutrient cycles and in the mitigation of greenhouse gas emissions from geothermal ecosystems. Here, we summarise the current knowledge on verrucomicrobial methanotrophs with respect to their metabolic versatility and discuss the factors that determine their diversity in their natural environment. In addition, key metabolic, morphological and ecological characteristics of verrucomicrobial and proteobacterial methanotrophs are reviewed.

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