Mass Loss Of Samples Research Articles

A generalized model of flame to surface heat feedback for laminar wall flames

In this work, experimental measurements of flame heat flux and sample mass loss rate are obtained as a diffusion flame spreads vertically upward (in the direction opposed to the vector of gravity) over the surface of seven commonly used polymeric materials, two of which are glass reinforced composites. Using these measurements, a previously developed empirical flame model specific to poly(methyl methacrylate) is generalized such that it can predict (flame to material surface) heat feedback from 3 to 20cm tall flames supported by a wide range of materials. Model generalization is accomplished through scaling on the basis of a material's gaseous pyrolyzate heat of combustion, which can be measured using mg-sized material samples in a microscale combustion calorimeter. For all seven materials tested in this work, which represent diverse chemical compositions and burning behaviors including polymer melt flow, sample burnout, and heavy soot and solid residue formation, model-predicted flame heat flux (to a water-cooled heat flux gauge) is shown to match experimental measurements taken across the full length of the flame with an average absolute error of 3.8kWm−2 (approximately 10–15% of peak measured flame heat flux). Coupled with a numerical pyrolysis solver, this generalized wall flame model provides the framework to quantitatively study material propensity to ignite and support early fire growth in a range of common scenarios with a level of accuracy and reduced computational cost unmatched by other currently available modeling tools.

A comparison between decay patterns of the white‐rot fungus Pleurotus ostreatus in chestnut–leaved oak (Quercus castaneifolia) shows predominantly simultaneous attack both in vivo and in vitro

SummaryIn this research, we examined decay patterns occurring in Quercus castaneifolia wood under natural conditions compared with controlled decay in vivo. Pleurotus ostreatus‐infected oak wood was obtained from the Sari forests in the north of Iran. The species causing decay was verified as P. ostreatus using rDNA‐ITS sequencing of pure cultures from infected sapwood. In addition to P. ostreatus, two wood‐inhabiting Ascomycota, Trichoderma harzianum and T. lixii, were present. Mass loss in oak sapwood samples exposed to P. ostreatus for 60 days was around 10 per cent. Samples were prepared from both naturally decayed wood and wood decayed under controlled conditions and examined using microscopy. P. ostreatus was found to produce a simultaneous white‐rot decay pattern in both conditions.

Термогравіметричні дослідження двокомпонентних епоксидних смол для виготовлення об’ємних етикеток

There was investigated the influence of temperature conditions on the stability of a polymer coating based on epoxy resins, which is used in the manufacture of volume labels by thermogravimetry.Objects of research were volumetric labels printed on a digital printing machine using transparent (glossy and matte) PVC films filled with different thicknesses of polymer coating. As a polymer coating, a soft and hard epoxy resin of 0.84 to 1.95 mm in thickness was used.The process of manufacturing volume labels included the preparation of an epoxy resin before applying a full-color printed image to the surface.Taking into account that for the production of volume labels we use multicomponent polymeric composite materials that are subject to heat treatment, for the study used thermogravimetric analysis, which involves studying the thermal stability of samples; with the registration of a similar signal of mass loss and thermal effects using a computer.It is proved that the sample of a volume label with soft epoxy resin demonstrates higher thermal stability. In the process of its heating during the studied temperature range there is less intensive mass lost compared with a label sample made of solid resin. The highs of exothermic effects of this sample shifted into higher temperatures range.Within the operating temperature range of 20–60° C samples of epoxy coating are heat resistant. In the process of heating the mass loss of samples does not exceed 0.5 % due to the allocation volatile compounds, which are present in them.The research allows to make the right choice of temperature conditions of polymer coatings formation based on of two-component epoxy resins in the manufacture of volume labels and conditions of their use.

Crude oil characterization using TGA-DTA, TGA-FTIR and TGA-MS techniques

In this research, combustion characterization and kinetics of four different origin crude oil samples were determined using thermogravimetry - differential thermal analysis (TGA-DTA) and thermogravimetry - Fourier transform infrared (TGA-FTIR) and thermogravimetry – mass spectrophotometry (TGA-MS) techniques.In the TGA-DTA analysis of crude oil samples, low temperature oxidation (LTO) and high temperature oxidation (HTO) reaction regions were observed in different temperature intervals. On the other hand, reaction regions, mass loss, and peak-burnout temperatures of the crude oil samples were also determined using TGA-DTA curves. In TGA-FTIR analysis, spectrums of crude oil samples were examined at different time intervals and composition of several hydrocarbon compounds was determined quantitatively. This research was also focused on the main volatile products (H2, H2O, CO, CO, C6H6, SO2 etc…) of different origin crude oil samples on the basis of both their relative intensities and on their relevancy by using TGA-MS technique.Two different Arrhenius types of kinetic models were used in order to determine the kinetic triplets (activation energy, Arrhenius constant and reaction order) of crude oil samples studied. It was observed that in HTO region, higher activation energy values were observed depending on the °API gravities of the crude oils.

Investigation of mechanical properties, morphology, and biodegradability of compositions based on polylactide and polysaccharides

The blends of polylactide with ethyl cellulose and chitosan are obtained in a Brabender mixer under conditions of high temperature shear deformation at different initial ratios of the reagents. The investigation of physicomechanical properties of the compositions has shown that the systems have high rigidity. Polyethylene glycol (PEG) and high-molecular-weight polyolefin polydecene have been added to the compositions in order to improve their elasticity. It has turned out that polydecene scarcely affects the mechanical characteristics, while PEG leads to a noticeable increase in elongation at break. Biodegradability of the compositions is investigated by the mass loss of samples after holding in soil, fungus resistance tests, and the analysis of the film morphology by scanning electron microscopy after holding in soil. It is found that the introduction of the third component (PEG) leads to an increase in biodegradability of the compositions.

Numerical analysis of Eucalyptus grandis × E. urophylla heat-treatment: A dynamically detecting method of mass loss during the process

Eucalyptus particles, lamellas and boards were applied to explore a simply-implemented method with neglected heat and mass transfer to inspect the mass loss during the heat-treatment course. The results revealed that the mass loss of a certain period was theoretically the definite integration of loss rate to time in this period, and a monitoring model for mass loss speed was developed with the particles and validated with the lamellas and boards. The loss rate was correlated to the temperature and temperature-evolving speed in the model which was composed of three functions during different temperature-evolving period. The sample mass loss was calculated in the MATLAB for the lamellas and boards and the model was validated and adjusted based on the difference between the computed results and the practically measured loss values. The error ranges of the new models were −16.30% to 18.35% for wood lamellas and −9.86% to 6.80% for wood boards. This method made it possible to acquire the instantaneous loss value through continuously detecting the wood temperature evolution. This idea could provide a reference for the Eucalyptus heat-treatment to detect the treating course and control the final material characteristics.

Crude extracts of two different leaf plant species and their responses against subterranean termite Coptotermes formosanus

Abstract. Indrayani Y, Muin M, Yoshimura T. 2016. Crude extracts of two different leaf plant species and their responses against subterranean termite Coptotermes formosanus. Nusantara Bioscience 8: 226-231. Crude extracts of plants consist of various chemical compounds useful for many purposes and their effects depend on the comprising active ingredients and applied concentrations. This study was conducted to determine the chemical compounds of plant leaf extracts and examine their responses against subterranean termite Coptotermes formosanus Shiraki. Two tropical plant species [clove (Syzygium aromaticum) and cajuput (Melaleuca leucadendra)] were extracted with 70% ethanol solvent. As the two different plant crude extracts contain eugenol, though to have termiticidal performance, various concentrations (0.1%, 0.05%, and 0.01%) based on their eugenol contents were prepared with filter paper samples for the test. The termite mortality and mass loss of extract-treated and untreated control filter paper samples were determined after four weeks of exposure. Results showed that crude extracts of different plant species showed different responses against the subterranean termites although they were applied at the same eugenol-based concentration. At the concentration of 0.1%, the crude extract of S. aromaticum caused termite mortality and consumption rates of 100% and 0.3%, respectively. Whilst, the crude extract of M. leucadendra caused significantly lower termite mortality (36.8%) and higher consumption (9.1%). Samples with lower eugenol-based concentration showed lower termite mortality and may have attractive effects on termites as indicated by higher consumption at the concentration of 0.01% compared to untreated controls. These results suggested that crude extracts of different two leaf species had different effects on subterranean termite C. formosanus even though they were applied at the same eugenol-based concentrations.

Protective Ceramic Coatings on the Base of the Refractory Metals Carbides

The aim of this work was obtaining of the protective coatings of the refractory metal carbides such as NbC, TaC, Cr7C3 on carbon steels and carbon fibers with further study their properties. The refractory metal carbides NbC, TaC, Cr7C3 were deposited on carbon steel and fibers by currentless transfer in molten salts at temperatures 1073-1123 K. The microhardness of refractory metal carbides on carbon steels at the cross section had the values 21 GPa, 29 GPa, 31 GPa for Cr7C3, NbC and TaC, respectively. The corrosion resistance of these carbides was studied in concentrated HCl, H2SO4 and H3PO4 acids at a room temperature during 48 hours. The corrosion tests were shown following rows of the chemical stability carbide coatings in HCl: Cr7C3>NbC>TaC; in H2SO4: TaC>Cr7C3>NbC; in H3PO4: Cr7C3>TaC>NbC. The wear resistance was evaluated by the mass loss of samples. The mass loss of a sample from a hardened St.3 was 35.2 mg cm-2 and that of a coated with a chromium carbide – 4.7 mg cm-2, niobium carbide – 2.9 mg cm-2 and tantalum carbide – 2.2 mg cm-2. Deposition of NbC coatings on parts of oil pumps increased their lifetime in several times. Coatings of Cr7C3 or TaC on the knifes for cutting rubber, made of St. 3, improve their wear resistance and increase a tool life in 2.0 – 2.5 times, respectively. Coatings of NbC or TaC on carbon fibers improve the mechanical resistance and they are compatible with fibers up to 1473 K in an aggressive atmosphere.

Influence of ammonium nitrate on the thermal decomposition of complex nitrogen–phosphorus–potassium fertilizers

The results of studying the thermal decomposition of complex nitrogen–phosphorus–potassium fertilizers obtained with different degrees of ammoniation of the mixture of nitric and phosphoric acid have been presented. The dependences of the mass loss of different samples and the release of the gas phase of nitrogen, fluorine, and chlorine compounds depending on the duration of decomposition have been shown.

Protective Ceramic Coatings on the Base of the Refractory Metals Carbides

The refractory metal carbides were deposited on carbon steel and fibers by currentless transfer in molten salts at temperatures 1073-1123 K. The microhardness of refractory metal carbides on carbon steels at the cross section had the values 21 GPa, 29 GPa, 31 GPa for Cr7C3, NbC and TaC, respectively. The corrosion resistance of these carbides was studied in concentrated HCl, H2SO4 and H3PO4 acids. The wear resistance was evaluated by the mass loss of samples. Deposition of NbC coatings on parts of oil pumps increased their lifetime in several times. Coatings of Cr7C3 or TaC on the knifes for cutting rubber, made of St. 3, improve their wear resistance and increase a tool life in 2.0 and 2.5 times respectively.

Cyclic oxidation behavior of SiC-containing self-healing TBC systems fabricated by APS

It is well-known that thermally grown oxide (TGO) deteriorates thermal barrier coating (TBC) systems after extended operating time. In this study, SiC-self-healing coatings (called “SAZ coatings” here) were investigated as a possible solution to enhance the oxidation resistance and spallation resistance of TBC systems. The self-healing-related filling and sealing effects of the proposed coatings were investigated and the oxidation resistance of the system after SAZ coating treatment was examined. To fully understand the oxidation resistance and spallation resistance mechanisms, we also conducted high-temperature cyclic oxidation tests (1100 °C) and recorded the mass gain and mass loss of samples after each cycle. Results showed that the corrosion current of YSZ/SAZ TBC samples decreased 79.23% after oxidation at 720 °C for a period of 10 h, and that 25.77% less TGO grew in YSZ/SAZ TBC samples after 20 h at 1100 °C compared to YSZ TBC samples due to the self-healing coating layer. The lifetime of YSZ/SAZ TBC was improved 58.33% compared to YSZ TBC in the high-temperature cyclic oxidation test, owing to the higher oxidation resistance and toughening effect of the SAZ coating.

Impact of a low pulsed electric field on the fungal degradation of wood in laboratory trials

Wood protection against fungal decay is mainly based on chemical protection. Nontoxic protection methods have become more important in Europe due to environmental concerns. A method using electric fields to inhibit wood decay by fungi has been investigated in laboratory trials and wood mass loss and moisture content after exposure to fungal attack were determined.The results show significantly reduced mass loss for wood samples exposed to a low pulsed electric field (LPEF), while wood samples connected to alternating and direct current displayed higher mass loss compared to LPEF. Changing the electrode material reduced the mass increase due to metal ion transfer into the wood samples for LPEF-exposed samples. The use of conductive polymer instead of metal electrodes and carbon fibers was preferable as no ions were transferred and the integrity of the material persisted. Decay of pre-exposed wood samples to white rot could be stopped or slowed down by means of LPEF.

Atomic Oxygen Influence on Polymer Nanocomposites with Different Fillers

This paper describes results of ground-based simulation of atomic oxygen influence on samples of polymer composites with different fillers. Polyimide and polyamide-imide were used as matrices, and polyorganosiloxanes, inorganic nanoparticles of , , WC, multiwalled carbon nanotubes, and detonation nanodiamonds were used as fillers. Data on mass loss of composite samples due to atomic oxygen exposure and results of surface morphology analysis are given.

Effect of the microstructure of Zn-Al and Zn-Al-Mg model alloys on corrosion stability

Zn-5Al and Zn-3Al-2Mg model alloys were cast and heat treated in order to obtain specimens with distinct microstructures and identical chemical compositions. The microstructure was characterised in detail to identify composition, size and distribution of present phases. Mass losses of samples with different microstructures and identical chemical compositions that were subjected to a cyclic corrosion test and a test under non-rinsing conditions differed by a factor of up to two. The mechanism is discussed based on measurements of corrosion stability of individual phases and chemical and phase compositions of corrosion products.

Chemical evaluation and kinetics of Siberian, north regions of Russia and Republic of Tatarstan crude oils

ABSTRACTIn this research, thermal characteristics and model free kinetics of five different °American Petroleum Institute gravity crude oil samples from different locations were studied using combustion calorimetry and thermogravimetry (TGA) techniques. Higher heating values of crude oils were determined from the combustion calorimetry experiments. It was shown that these values increase with an increase in saturate fraction and °API gravity of studied samples and decrease with an increase in viscosity, aromatics fraction, and resin fraction of crude oils. In thermogravimetry, experiments were performed at 10, 20, and 30°C/min heating rates under an air atmosphere. Thermal characteristics of the samples such as reaction intervals and corresponding peak temperatures, mass loss, and residue of the crude oil samples were also determined. Two different model free kinetic methods, known as Ozawa–Flynn–Wall (OFW) and Kissinger–Akahira–Sunose (KAS), were used in order to determine the activation energy values of the crude oil samples studied.

Torrefaction of almond shells: Effects of torrefaction conditions on properties of solid and condensate products

Almond shells were torrefied in a fixed bed reactor and their solid and condensate products were collected for analysis. Response surface methodology was used to examine effects of torrefaction temperature (230°C, 260°C, and 290°C) and time (60, 80, and 100min) on mass and energy yields of solid products as well as mass yields and gross calorific values (GCVs) of condensate products. This was the first study on condensates produced during torrefaction of almond shells. Also, true density, moisture sorption isotherms, thermal stability, and elemental composition of the solid products were characterized. The mass yields of solid products drastically decreased at higher temperatures, from 85.4–92.7% at 230°C to 39.4–45.3% at 290°C. Also, mass yields (8.79–11.71% at 230°C to 23.13–29.39% at 290°C) and GCVs of condensates (2.3±0.3 to 4.3±1.0MJ/kg at 230°C to 5.6±1.0 to 7.1±1.2MJ/kg at 290°C) generally increased in value at higher temperatures and longer times. Moisture sorption isotherms of torrefied shells were measured for the first time and all torrefied shells had lower equilibrium moisture contents than raw shells. In addition, equilibrium moisture contents and GCVs of the condensates were found, for the first time, to be predicted relatively well using just the sample mass loss results. The minimum moisture contents were predicted to occur at 16.4–19.9% mass loss.

Determining the wear and abrasive properties of foundry coke

No standard methods exist for determining the wear and abrasive properties of coke corresponding to its motion on conveyers or in the furnace shaft. A test method is proposed for determining the wear and abrasion of foundry coke, on a vibrational system; the effective total vibrational amplitude is 1.6 mm. For the tests, samples of size classes 40–60 and 60–80 mm are taken from four different batches of foundry coke. In the tests, the vibrator, equipped with a special attachment in the form of a chamber with an aluminum plate at the bottom, transmits vibrations to the coke sample. The test time is 30 min. The relative mass loss of the coke sample indicates its wear, while the relative mass loss of the aluminum plate indicates the abrasive properties of the coke. The test results correspond to coke strength M 40. Coke of the 60–80 mm class is more abrasive than coke of the 40–60 mm class. With increase in strength of the foundry coke, its wear is reduced by 22% for the 40–60 mm class and by 41% for the 60–80 mm class. The coke’s abrasive action is increased by a factor of 7.6 and 2.3, respectively

Electrical properties of triple-doped bismuth oxide electrolyte for solid oxide fuel cells

ABSTRACTIn this study, the quaternary solid solutions of (Bi2O3)(0.8−x)(Tb4O7)0.1(Ho2O3)0.1(Dy2O3)x (x = 0.05, 0.10, 0.15, 0.20) as an electrolyte were synthesized for solid oxide fuel cells by the technique of solid-state synthesis.The products were characterized by X-ray powder diffraction, differential thermal analysis/thermal gravimetry and the four-point probe technique (4PPT). The total electrical conductivity is measured on the temperature and the doped concentration by 4PPT.All samples have been obtained as the δ-phase. According to the measurements of the 4PPT, the electrical conductivities of the samples increase with the temperature but decrease with the amount of doping rate. The value of the highest conductivity (σ) is found as 1.02 × 10−1 S cm−1 for the system of (Bi2O3)0.75(Tb4O7)0.1(Ho2O3)0.1(Dy2O3)0.05 at 850 °C. The thermal gravimetry (TG) curve shows that there is no mass loss of sample during the measurement. The analyses of differential thermal reveal that there are neither endothermic peaks nor exothermic peaks during the heating and cooling cycles (ranging from 30 to 1000 °C).

Effect of microstructure on chemical stability and electrical properties of BaCe0.9Y0.1O3 − δ

Y-doped barium cerate BaCe0.9Y0.1O3 − δ was synthesised by a solid-state reaction method. Materials with different average grain sizes and grain boundary surface areas were obtained. The effect of microstructure on the chemical stability in the CO2 and H2O-containing atmosphere and electrical properties was analysed and discussed. To evaluate the chemical stability of BaCe0.9Y0.1O3 − δ , the exposure test was performed. Samples were exposed to the carbon dioxide and water vapour-rich atmosphere at 25 °C for 700 h. Thermogravimetry supplied by mass spectrometry was applied to analyse the samples before and after this comprehensive test. The mass loss for samples before and after the test and the amount of BaCO3 formed during the test were directly treated as the measure of chemical instability of BaCe0.9Y0.1O3 − δ in the atmosphere rich in carbon dioxide and water vapour. As it was observed, the BaCe0.9Y0.1O3 − δ chemical stability towards CO2 and H2O is not affected by the materials’ microstructure. Electrical properties of BaCe0.9Y0.1O3 − δ which differs with microstructure were determined using electrochemical impedance spectroscopy (EIS). It was found that the grain interior resistivity and activation energy of grain interior conductivity is microstructure independent. However, the effect on microstructure was seen on the EIS spectra in the range of grain boundary contribution. Therefore, the lowest activation energy and the highest conductivity were observed for a material with the lowest grain boundary surface area.

Enhancement of high temperature oxidation resistance and spallation resistance of SiC-self-healing thermal barrier coatings

Abstract Thermal barrier coatings (TBCs) are extensively used to protect metallic blades in gas-turbine engines where the operating conditions include an aggressive environment at high temperatures. The most important factor controlling TBC durability is the growth of a thermally grown oxide (TGO) layer which is formed during high temperature oxidation. To improve the oxidation resistance of conventional TBC, the SiC-self-healing coating, named the SAZ coating, was prepared by air plasma spray (APS) technique on the top of the classic bilayer TBC (YSZ TBC), which consist of the bond coating (BC) and the YSZ coating. Cracks allow SiC particles locating on the crack outside surface to react with the oxygen in the atmosphere at the temperature above 720 °C resulting in healing. As oxidation progress, the crack surfaces are covered with the formed oxide. Finally, the space between the crack surfaces is completely or incompletely filled with the formed oxide. The sealing effect enhanced the oxygen diffusion resistance of SAZ coatings, therefore the partial pressure of oxygen at the BC-YSZ interface of SAZ TBC samples would be lower than of YSZ TBC samples. The oxidation and spallation resistance of the SAZ TBC samples will be enhanced because the growth rate of TGO is slower due to the low partial pressure of oxygen. The high temperature cyclic oxidation tests performed at 1127 °C was carried out to investigate the oxidation and spallation resistance of the SAZ TBC. The results demonstrated that the mass gain of SAZ TBC samples, which was related to oxidation resistance, was 63.29% of YSZ TBC samples, and the mass loss of SAZ TBC samples, which was related to spallation resistance, was 56.08% of YSZ TBC samples.