Phase relations in the CaO–SiO2–H2O system to 200 °C at saturated steam pressure

2004 ◽  
Vol 34 (9) ◽  
pp. 1529-1534 ◽  
Author(s):  
S.-Y. Hong ◽  
F.P. Glasser
Keyword(s):  
Steam Pressure ◽  
Phase Relations ◽  
Saturated Steam

scholarly journals Comparative evaluation of the efficacy of plants for disinfection of medical waste

2019 ◽  
Vol 95 (7) ◽  
pp. 614-617 ◽  
Author(s):  
Alisa V. Balakayeva ◽  
N. V. Rusakov
Keyword(s):  
Comparative Evaluation ◽  
Steam Pressure ◽  
Medical Waste ◽  
Saturated Steam ◽  
Physical Methods ◽  
Microwave Exposure ◽  
Moist Heat ◽  
Chemical Disinfection

There are presented results of the comparative evaluation of the effectiveness of plants for disinfection of medical waste which use 4 most common hardware technologies: treatment by saturated steam pressure, moist heat, microwave exposure and chemical disinfection with refinement. The efficiency ofplants using physical methods of influence was shown to be higher in comparison with hardware chemical disinfection.

Thermodynamics of James Watt – Ignored or not Understood?

2021 ◽  
Vol 42 (3) ◽  
pp. 397
Author(s):  
Jovan Mitrovic
Keyword(s):  
Latent Heat ◽  
Heat Engine ◽  
Primary Source ◽  
Rankine Cycle ◽  
Theoretical Work ◽  
Steam Pressure ◽  
Steam Engine ◽  
Saturated Steam ◽  
Maximum Efficiency ◽  
Starting Point

In the analysis of the development of thermodynamics as a science, the theoretical work of Sadi Carnot, published in 1824, is generally considered to be the starting point. Carnot studied the cycle of an ideal heat engine and formulated the condition for its maximum efficiency. In this article we examine James Watt’s contributions to the formation of fundamental concepts of thermodynamics, made in the course of his work on improving the Newcomen engine and developing his own steam engine. It is shown that Watt was the first to characterize thermodynamic properties such as latent heat and vapor density. The authors prove Watt’s priority in the studies of the dependence of saturated steam pressure on temperature, in which a critical point was found when the latent heat disappears. These results of Watt anticipated by many decades the studies on the thermodynamic critical state by Th. Andrews and J. Thomson. The article also discusses Wattʼs research on thermodynamic cycles. It is shown that he was the first to study the Rankine cycle with superheated steam, known from the history of thermodynamics. Watt was also the first scientist to introduce the concept of a steam engine’ volumetric work as the product of pressure and volume, and developed a device, the steam pressure indicator, to measure its value. We show the results obtained by Watt with steam to be considerably ahead of Prescott Jouleʼs work on the cooling and condensation of gases during expansion. The article presents an interpretation of Watt’s 1769 patent that is very important as the primary source for a subsequent study and establishment of the principles of energy conversion. The factual material presented in this article suggests that Watt’s scientific research have not been properly understood or simply went unnoticed.

scholarly journals Impact of Instant Controlled Pressure Drop (DIC) Treatment on Drying Kinetics and Caffeine Extraction from Green Coffee Beans

2012 ◽  
Vol 1 (1) ◽  
pp. 24 ◽  
Author(s):  
I. Kamal ◽  
A. Gelicus ◽  
K. Allaf
Keyword(s):  
Pressure Drop ◽  
Initial Moisture Content ◽  
Effective Diffusivity ◽  
Steam Pressure ◽  
Raw Material ◽  
Saturated Steam ◽  
Drying Time ◽  
Hot Air ◽  
Instant Controlled Pressure Drop ◽  
The Impact

<p>The present work is directed towards the impacts of Détente InstantanéeContrôléeDIC (French, for instant controlled pressure-drop) in terms of decaffeination and drying of Ethiopian green coffee beans (GCBs).DICconsisted in subjecting the product to a high-pressure saturated steam during some seconds and ended with an abrupt pressure drop towards a vacuum. A conventional aqueous extraction and a hot air-drying took place after DIC treatment. Inthis study, Response Surface Method (RSM) was used withDIC saturated steam pressure P, thermal treatment time t, and initial moisture content W asthe independent variables. Both direct DICextract recovered from the vacuum tank and the aqueous extracts wereanalyzed and quantified using the reversed phase-HPLC. With decaffeination ratiosas dependent variables, P and Wwere the most significant operating parameters; whilet was much weaker.Total decaffeination ratio could reach 99.5% after DIC treatment at specificconditions of W=11.00% db, P=0.1 MPa, and t=35swhile it was only 58% when achieved with untreated raw material.</p> The effective diffusivity  and the starting accessibility  were calculated from the diffusion/surface interaction kinetic model of hotair drying after DIC treatment. They dramatically increased with P and t while W had a weak impact.Thus, at the optimized DICconditions, and  increased from 0.33 to 12.60 10<sup>-10</sup>m² s<sup>-1</sup>and from 0.75 to 11.53 g/100 g db, respectively. Drying time needed to reach 5% db became 60 min instead of 528 min for untreated raw material. <p>RSM analysis showed that the DIC saturated steam pressure P and the initial moisture content W were the most significant variables both affecting the decaffeination ratio; the impact of the total thermal processing time t was much weaker. Total decaffeination ratio could reach 99.5% after DIC treatment at specific conditions of W=11.00% db, P=0.1 MPa, and t=35 s while it was only 58% when achieved with untreated raw material.</p> <p>Using diffusion/surface interaction model of hot-air drying kinetics just after DIC treatment, we could observe that DIC expansion dramatically improved the drying kinetic parameters, with P and t as the most significant DIC operating parameters while the impact of W was much weaker. Thus, the optimized DIC treatment allowed the effective diffusivity  and the starting accessibility to increase from 0.33 10<sup>-10</sup> m² s<sup>-1</sup> and 0.75 g/100 g db to 12.60 10<sup>-10</sup> m² s<sup>-1</sup> and 11.53 g/100 g db, respectively. Drying time needed to reach 5% db became 60 min instead of 528 min for untreated raw material.</p>

scholarly journals Comparative Study of the Effects of Drying Methods on Antioxidant Activity of Dried Strawberry (Fragaria Var. Camarosa)

2013 ◽  
Vol 2 (2) ◽  
pp. 92 ◽  
Author(s):  
Maritza Alonzo-Macías ◽  
Anaberta Cardador-Martínez ◽  
Sabah Mounir ◽  
Gerardo Montejano-Gaitán ◽  
Karim Allaf
Keyword(s):  
Antioxidant Activity ◽  
Steam Pressure ◽  
Saturated Steam ◽  
Drying Methods ◽  
Anthocyanin Content ◽  
Flavonoid Content ◽  
Hot Air Drying ◽  
Total Anthocyanin ◽  
Hot Air ◽  
Instant Controlled Pressure Drop

<p>Hot air drying (HAD), freeze-drying (FD), and swell-drying (SD, coupling instant controlled pressure drop, DIC, to standard hot air) were applied to strawberries (<em>Fragaria</em> var. Camarosa). The total phenol, total flavonoid, and total anthocyanin contentswere evaluated versusthe drying methods. The correlations between the bioactive compounds and antioxidant activity were investigated. The obtained results showed that the differences in phenol levels were no quite comparing the three drying techniques; however, great variations were reported for anthocyanin and flavonoid content.</p> A strong correlation between the antioxidant activity and anthocyanin content was found in SD strawberries. Also, it was observed that saturated steam pressure (P) of DIC texturing operation, had a significant effect on the studied parameters compared to the thermal holding time (t). The optimum conditions of DIC were P = 0.35 MPa for t = 10 s to obtain the highest levels of phenols, flavonoids, and anthocyanins, as well as antioxidant activity.

Modeling On/Off-Design Performance of Solar Tower Plants Using Saturated Steam

2010 ◽  
Author(s):  
F. Colzi ◽  
S. Petrucci ◽  
G. Manzolini ◽  
R. Chacartegui ◽  
P. Silva ◽  
...  
Keyword(s):  
Steam Generator ◽  
Initial Conditions ◽  
Steam Pressure ◽  
Operating Conditions ◽  
Live Steam ◽  
Saturated Steam ◽  
Critical Element ◽  
Mass Balances ◽  
Steam Generation ◽  
Ambient Conditions

This works presents a model for the performance prediction of concentrating solar tower plants using saturated live steam at on and off-design. For solar tower plants, the most important and critical element is the steam generator that, in this model, is supposed to produce saturated steam. The solar receiver is thus assumed to comprise several panels, each one of which is formed by a number of pipes. Given some boundary and initial conditions, heat and mass balances for the plant at any rated conditions can be obtained. Off-design operation is then defined by a modified map of the radiative heat flow onto the panels, though other operating conditions featuring new ambient conditions or abnormal operation of the plant can be simulated as well. As a result, a new set of heat and mass balances and performance data — efficiency, steam generation, live steam pressure and temperature, bleed pressures — are obtained. The developed model demonstrates its functionality during the design process in three ways. On one hand it allows to calculate and optimize the performance of the plant at rated conditions, developing a sensitivity analysis of the parameters involved. On the other hand, various off-design conditions can be studied and, consequently, it is possible to carry out a long term — for instance yearly — thermodynamic and economical analysis. Finally, it allows detecting undesirable operating conditions of one or more components that could eventually lead to a not admissible operation of the plant: for example a too high vapor fraction in the steam generator, a too low deaerator pressure, cavitation of pumps or other situations that are not appropriate for the steam turbine.

The Chemistry of Al-Tobermorite and its Coexisting Phases AT 175°C

1989 ◽  
Vol 179 ◽  
Author(s):  
Mary W. Barnes ◽  
Barry E. Scheetz
Keyword(s):  
Interlayer Spacing ◽  
Steam Pressure ◽  
Major Effect ◽  
Saturated Steam ◽  
X Ray Diffraction ◽  
Constant Composition ◽  
Hydrothermal Conditions ◽  
Coexisting Phases ◽  
Approach To Steady State ◽  
Tie Line

AbstractThe substitution of Al into the structure of tobermorite was investigated, along with the resultant phase assemblages that compatibly coexist with the Al-tobermorite. All experiments were conducted under hydrothermal conditions at saturated steam pressure. The temperatures of the experiments varied from 90° to 190°C and times from 1 to 28 days. Ca/Si ratios varied from 0.7 to 1.7, Al/(Al+Si) from 0.12 to 0.30. NaOH varied from none to 5 moles/mole tobermorite constituents. X-ray diffraction was used not only to identify phases but to determine degree of substitution and the rate of approach to steady state.Maximum Al substitution was found to be Al/(Al+Si) = 0.13, and the maximum interlayer spacing was 11.42 ± 0.015 Å. This is in agreement with previously published work which found a trace of hydrogarnet at Al(Al+Si) = 0.15 and a maximum interlayer spacing of 11.45 ± 0.02 A. When Al concentrations in the mix are greater than enough to make maximum Al-tobermorite, “low”-hydrogarnet (“low”-hydrogarnet has ∼0.1 SiO2 per mole). As Al concentration is raised, a variable composition hydrogamet is formed and then a “high”-garnet of constant composition (SiO2 = 0.7 moles/mole hydrogarnet) is formed.NaOH was found to have a major effect on the kinetics and the phase assemblages at a given time. Al-tobermorite, although stable at 90°C, converts to xonotlite at 175°C in the absence of NaOH. In its presence, even at a level too low to make Na-containing phases, Al-tobermorite persists at 21 days at 175°C. In the absence of NaOH, at 175°C, Al-tobermorite forms at up to 7–10 days but is converted to xonotlite at 28 days. Coexisting phases are gyrolite and cowlesite at Ca/Si ≥ 1 and hillebrandite and “low”-garnet at Ca/Si > 1. When there is enough NaOH to form Na-containing phases, Al-tobermorite coexists with reyerite and analcime at Ca/Si > 1. At Ca/Si < 1 and Al less than the composition on the tie line between Al-tobermorite and “low”-garnet, Al-tobermorite coexists with “low”-garnet and portlandite. In the compatibility triangle between Al-tobermorite, “low”-garnet, and “high”-garnet, Al-tobermorite coexists with variable Si-gamet. When Al exceeds its limiting value on the tie line, Al-tobermorite-“high”-gamet, the assemblage is Al-tobermorite-“high”-gamet-cowlesite.

Effect of Hydration Products Transformation for Compressive Strength of Autoclaved Silicate Products

2012 ◽  
Vol 204-208 ◽  
pp. 3644-3647
Author(s):  
Chang Jun Ke ◽  
Shu Ying Wang ◽  
Jun Li Liu
Keyword(s):  
Compressive Strength ◽  
Steam Pressure ◽  
Diffraction Peak ◽  
Saturated Steam ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Diffraction Peaks ◽  
The Relationship

the relationship between hydration products transformation and the compressive strength was studied with X-ray diffraction, infrared spectroscopy analysis. The results showed, 0.505nm hydrogarnets diffraction peaks weakened and 0.183nm CSH diffraction peak enhanced with different autoclaved time under 1.2MPa saturated steam pressure. 0.505nm hydrogarnets diffraction peak enhanced under lower saturated steam pressure for autoclaving 6h, then weaken under higher saturated steam pressure. And 0.183nm CSH diffraction peaks enhanced with different saturated steam pressure for autoclaving 6h. During autoclaving, hydrogarnet translate into Al-substituted calcium silicate hydrate (C-S-H). Transformation of hydration products is favorable for compressive strength of autoclaved sample.

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