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Number of results: 4
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Abstract

A simplified isoperibol calorimetry method for measuring specific heat in solids is described. Taking advantage of the classical Nernst dependency the specific heat is calculated from time-domain temperature curves registered for a sample forced heating and natural cooling phase. In order to improve accuracy of the measurements a correction factor, taking into account the heat transferred to the surrounding, is introduced along with a procedure of statistical elimination of unavoidable measurement deviations. The method is implemented in a simple and straightforward measuring system involving no vacuum calorimeter. The method is applicable for quick and routine specific heat measurements performed on small solid dielectric or metallic specimens at near-room temperature. Test results of various materials used commonly in electrical engineering are demonstrated and discussed as well as comparison to drop calorimetry and differential scanning calorimetry reference measurements is included. The overall repeatability of the test method and the simplified apparatus is estimated as not worse than 2.6%.
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Authors and Affiliations

Leszek Moroń
Paweł Żyłka
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Abstract

Reaction kinetics of acetic anhydride hydrolysis reaction is being studied at a fixed reaction temperature and ambient pressure using an isoperibolic reaction calorimeter. Temperature versus time data along with heat and mass balance is used to determine the kinetics parameters i.e. activation energy and Arrhenius coefficient. It has been studied with the varying volumetric ratio of acetic anhydride and water; and kinetics parameters were compared and plotted for each ratio. Such a study has not been done previously to determine the kinetics dependency on varying the acetic anhydride water ratio. As the acetic anhydride hydrolysis reaction is exothermic in nature, the present study will help to decide the safe and suitable operating conditions such as concentration and temperature for conducting this reaction at plant scale. The kinetic data presented can be used further for the mathematical modeling and simulation of such exothermic hydrolysis reactions.
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Authors and Affiliations

Rajendra Kumar
1
Anurag Kumar Tiwari
2

  1. Council of Scientific and Industrial Research – National Chemical Laboratory, Chemical Engineering and Process Development Division, Pune, India – 411008
  2. Dr B R Ambedkar National Institute of Technology, Department of Chemical Engineering, Jalandhar, Punjab, India – 144011
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Abstract

Coffee is grown in over 50 countries around the world, and its sale is the largest in the world trade after crude oil. In the case of coffee beans, after consumption remains a solid waste in the form of a waste plant extract. At present, coffee waste is not fully managed, which means that it is often deposited in landfills. Taking into account their availability on the market and the content of significant amounts of carbon in them, it was proposed to use them as a reducing agent in the processing of copper slags. The use of Solid Coffee Grounds (SCG) as an alternative reducing agent for coke and coke breeze can be beneficial in two aspects. The first is the reduction of carbon dioxide emissions in the process, and the second is due to the possible release of hydrocarbons from these wastes at high temperatures, which, apart from participating in the reduction process itself, causes also mixing of the bath in the melting unit, which facilitates the process of copper sedimentation in the slag. The experiments carried out on a laboratory scale showed the possibility of reducing the copper content in the slag after the reduction process from 10.3 to 0.41 % by mass. The obtained values of the relative degree of copper splashing for all experiments ranged from 88.4 to 96.0 %. The presented solution is an innovative approach to the use of SCG in the processing of copper slags.
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Authors and Affiliations

T. Matuła
1
ORCID: ORCID
Ł. Kortyka
Ł. Myćka
2
J. Łabaj
1 2
ORCID: ORCID
T. Wojtal
1

  1. Silesian University of Technology, Faculty of Materials Engineering, Krasińskiego 8, 40-019 Katowice, Poland
  2. Łukasiewicz Research Network - Institute of Non-Ferrous Metals, Sowińskiego 5, 44-100 Gliwice, Poland
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Abstract

Paper presents the results of evaluation of heat resistance and specific heat capacity of MAR-M-200, MAR-M-247 and Rene 80 nickel

superalloys. Heat resistance was evaluated using cyclic method. Every cycle included heating in 1100°C for 23 hours and cooling for 1

hour in air. Microstructure of the scale was observed using electron microscope. Specific heat capacity was measured using DSC

calorimeter. It was found that under conditions of cyclically changing temperature alloy MAR-M-247 exhibits highest heat resistance.

Formed oxide scale is heterophasic mixture of alloying elements, under which an internal oxidation zone was present. MAR-M-200 alloy

has higher specific heat capacity compared to MAR-M-247. For tested alloys in the temperature range from 550°C to 800°C precipitation

processes (γ′, γ′′) are probably occurring, resulting in a sudden increase in the observed heat capacity.

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Authors and Affiliations

R. Przeliorz
M. Góral
P. Gradoń
F. Binczyk
T. Mikuszewski

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