scholarly journals The Role of H2:N2 Ratio on the NH3 Synthesis Rate and on Process Economics over the Co3Mo3N Catalyst

2020 ◽  
Author(s):  
Mustafa Yasin Aslan ◽  
Justin Hargreaves ◽  
Deniz Uner
Keyword(s):  
Atmospheric Pressure ◽  
Ammonia Synthesis ◽  
Synthesis Rate ◽  
Process Economics

In this study, the process economics of ammonia synthesis over Co3Mo3N was investigated by searching an optimum feed stoichiometry. By ammonia synthesis rate measurements at atmospheric pressure and 400 oC...

Microstructure and reactivity of small metal particles: The role of Ce additives

1992 ◽  
Vol 50 (1) ◽  
pp. 318-319
Author(s):  
L.D. Schmidt ◽  
K. R. Krause ◽  
J. M. Schwartz ◽  
X. Chu
Keyword(s):  
Atmospheric Pressure ◽  
Noble Metals ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Chemical Shifts ◽  
Catalytic Converter ◽  
Structural Evolution ◽  
Single Particles ◽  
Small Metal Particles

The evolution of microstructures of 10- to 100-Å diameter particles of Rh and Pt on SiO2 and Al2O3 following treatment in reducing, oxidizing, and reacting conditions have been characterized by TEM. We are able to transfer particles repeatedly between microscope and a reactor furnace so that the structural evolution of single particles can be examined following treatments in gases at atmospheric pressure. We are especially interested in the role of Ce additives on noble metals such as Pt and Rh. These systems are crucial in the automotive catalytic converter, and rare earths can significantly modify catalytic properties in many reactions. In particular, we are concerned with the oxidation state of Ce and its role in formation of mixed oxides with metals or with the support. For this we employ EELS in TEM, a technique uniquely suited to detect chemical shifts with ∼30Å resolution.

scholarly journals Decoupling of ground level pressures observed in Italian volcanoes: are they driven by space weather geo-effectiveness?

2014 ◽  
Vol 57 (3) ◽  
Author(s):  
Paolo Madonia ◽  
Paolo Romano ◽  
Salvatore Inguaggiato
Keyword(s):  
Space Weather ◽  
Atmospheric Pressure ◽  
Pressure Field ◽  
Ground Level ◽  
Total Solar Irradiance ◽  
Weather Parameters ◽  
Sun Activity ◽  
Fft Analysis ◽  
Sunspot Groups

<p>Investigations on correlation drops between near-ground atmospheric pressures measured at sea level and at higher altitudes on Italian volcanoes have been carried out. We looked for perturbations of the atmospheric pressure field driven by volcanic activity, but not excluding possible external triggers for the observed anomalies. Decorrelations between atmospheric pressures measured at Stromboli Island in stations located at different altitudes (years 2002-10) have been analysed and compared with data from other volcanic (Vesuvius) and non volcanic (Mt. Soro) orographic structures. We investigated as their possible triggers volcanic, meteorological and space weather parameters, with particular attention to Total Solar Irradiance (TSI), Kp index and Forbush decreases. Pressure decorrelations seems to be driven by astronomic cycles, with maxima in summer and minima in winter. A further contribution was found, seemingly assignable to TSI anomalies, with correlation minima occurring 12 hours after these but only during phases of high Sun activity. Moreover, during the same phases a main periodicity of about 27 days in pressure decorrelations was revealed by FFT analysis. This period is the same of the Sun Carrington rotation, expressing the periodic reappearance of sunspot groups on Sun’s surface. The strong similarity between recurrences of sunspot number and atmospheric pressure anomalies further supports the role of the former as a possible trigger for the latter.</p>

scholarly journals The influence of argon gas flow in the killing of staphylococcus epidermidis bacteria

2018 ◽  
Vol 16 (36) ◽  
pp. 134-139
Author(s):  
Ahmed Mahmoud Shihab
Keyword(s):  
Staphylococcus Epidermidis ◽  
Atmospheric Pressure ◽  
Gas Flow ◽  
Biotechnological Applications ◽  
Plasma System ◽  
Argon Gas ◽  
Killing Rate ◽  
Normal Atmospheric Pressure ◽  
Non Thermal Plasma

In this research, non-thermal plasma system of argon gas is designed to work at normal atmospheric pressure and suitable for work in medical and biotechnological applications. This technique is applied in the treatment of the Staphylococcus epidermidis bacteria and show the role of the flow rate of Argon gas on the killing rate of bacteria, and it obtained a 100 % killing rate during the time of 5 minutes at the flow Argon gas of 5 liters/ min.

Decrease in ureagenesis by partial hepatectomy does not influence acid-base balance

1989 ◽  
Vol 257 (4) ◽  
pp. F696-F699
Author(s):  
T. Almdal ◽  
H. Vilstrup ◽  
K. Bjerrum ◽  
L. O. Kristensen
Keyword(s):  
Sodium Chloride ◽  
Sodium Bicarbonate ◽  
Synthesis Rate ◽  
Urea Synthesis ◽  
Ph Homeostasis ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance ◽  
Bicarbonate Infusion

It has been suggested that urea synthesis participates directly in body pH homeostasis by removal of bicarbonate. To elucidate this hypothesis sodium bicarbonate or sodium chloride was infused (11.5 mumol/min) for 90 min into control rats and into rats that had undergone an 85% hepatectomy immediately before starting the infusion. Urea synthesis rate was 2.6 +/- 0.3 mumol/min (mean +/- SE) in controls, and was significantly (P less than 0.01) reduced to 1.0 +/- 0.2 mumol/min in partially hepatectomized rats. At the start of bicarbonate infusion, pH was 7.38 and 7.34 in control and partially hepatectomized rats, respectively, and at the end of infusion, pH was 7.56 and 7.51. Standard bicarbonate at start of bicarbonate infusion was 21.9 and 21.3 mM in controls and partially hepatectomized, respectively, and it increased to 32.7 and 29.9 mM at end of infusion. In saline-infused rats a slight decrease of approximately 0.05 pH units was observed during the experiment, but again no difference emerged between control and partially hepatectomized rats. It is concluded that a major role of the liver in the regulation of acid-base balance is unlikely.

scholarly journals On the Role of Mechanical Energy in Maintaining Subglacial Water Conduits at Atmospheric Pressure

1984 ◽  
Vol 30 (105) ◽  
pp. 180-187 ◽  
Author(s):  
Roger Leb. Hooke
Keyword(s):  
Atmospheric Pressure ◽  
Flow Direction ◽  
Mechanical Energy ◽  
Glacier Surface ◽  
Ice Flow ◽  
Small Perturbations ◽  
Point Pressure ◽  
Ice Velocity ◽  
Glacial Landforms

AbstractRecent theoretical studies of glacier hydrology have assumed that subglacial conduits are completely filled with water under steady-state conditions. This, however, is not necessarily the case. Where discharges are larger than a few tens of liters per second and the down-glacier slope of the bed is more than a few degrees, the potential energy released by water descending this slope may be capable of melting the walls of a subglacial conduit many times faster than the conduit can close by plastic flow of the ice. As a result, the pressure in such tunnels may normally be atmospheric, or possibly even at the triple-point pressure if there is no open connection to the glacier surface. Simple calculations suggest that such pressures in subglacial conduits may be more common than heretofore anticipated.The positions of such “open” conduits may be unstable to small perturbations in discharge or ice velocity. This is because the mechanical energy available in excess of that needed to balance closure can instead offset the general flow of the ice. Conduits can thus trend diagonally across the direction of ice flow. If an increase in the angle which such a conduit makes with the ice flow direction also results in an increase in slope of the conduit, more mechanical energy will become available, resulting in a positive feedback process.Subglacial channels at atmospheric pressure may influence the origin and morphology of certain glacial landforms, such as eskers and “plastically-molded” features.

scholarly journals The role of humidity and UV-C emission in the inactivation of B. subtilis spores during atmospheric-pressure dielectric barrier discharge treatment

2020 ◽  
Vol 53 (29) ◽  
pp. 295201
Author(s):  
Friederike Kogelheide ◽  
Farina Voigt ◽  
Bastian Hillebrand ◽  
Ralf Moeller ◽  
Felix Fuchs ◽  
...  
Keyword(s):  
Dielectric Barrier Discharge ◽  
Atmospheric Pressure ◽  
Barrier Discharge ◽  
Dielectric Barrier ◽  
Discharge Treatment ◽  
Uv C

scholarly journals The role of heterogeneous catalysts in the plasma-catalytic ammonia synthesis

2021 ◽  
Vol 362 ◽  
pp. 2-10 ◽  
Author(s):  
Bhaskar S. Patil ◽  
Nikolay Cherkasov ◽  
Nadadur Veeraraghavan Srinath ◽  
Juergen Lang ◽  
Alex O. Ibhadon ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Ammonia Synthesis ◽  
Catalytic Ammonia Synthesis

scholarly journals Impact of biomass burning emission on total peroxy nitrates: fire plume identification during the BORTAS campaign

2016 ◽  
Vol 9 (11) ◽  
pp. 5591-5606 ◽  
Author(s):  
Eleonora Aruffo ◽  
Fabio Biancofiore ◽  
Piero Di Carlo ◽  
Marcella Busilacchio ◽  
Marco Verdecchia ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atmospheric Pressure ◽  
Thermal Dissociation ◽  
Ann Model ◽  
Fire Plume ◽  
Pressure Threshold ◽  
Peroxy Nitrates ◽  
Artificial Neural Network Ann ◽  
The Impact

Abstract. Total peroxy nitrate ( ∑ PN) concentrations have been measured using a thermal dissociation laser-induced fluorescence (TD-LIF) instrument during the BORTAS campaign, which focused on the impact of boreal biomass burning (BB) emissions on air quality in the Northern Hemisphere. The strong correlation observed between the  ∑ PN concentrations and those of carbon monoxide (CO), a well-known pyrogenic tracer, suggests the possible use of the  ∑ PN concentrations as marker of the BB plumes. Two methods for the identification of BB plumes have been applied: (1)  ∑ PN concentrations higher than 6 times the standard deviation above the background and (2)  ∑ PN concentrations higher than the 99th percentile of the  ∑ PNs measured during a background flight (B625); then we compared the percentage of BB plume selected using these methods with the percentage evaluated, applying the approaches usually used in literature. Moreover, adding the pressure threshold ( ∼  750 hPa) as ancillary parameter to  ∑ PNs, hydrogen cyanide (HCN) and CO, the BB plume identification is improved. A recurrent artificial neural network (ANN) model was adapted to simulate the concentrations of  ∑ PNs and HCN, including nitrogen oxide (NO), acetonitrile (CH3CN), CO, ozone (O3) and atmospheric pressure as input parameters, to verify the specific role of these input data to better identify BB plumes.

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