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Mitigation and Adaptation Strategies for Global Change

The air/steam gasification of wood sawdust (SD), plum and olive pits (PP, OP) bio-wastes was studied using macro-thermogravimetric analysis at three heating rates (5, 10, 15 K/min). Three stages were identified during gasification process: water vaporization; de-volatilization and char gasification. The experimental data were analysed by applying five model-free methods: Flynn-Wall-Ozawa (FWO), Distributed Activation Energy Model (DAEM), Friedman, Starink, and Kissinger-Akahira-Sunose (KAS), to evaluate the gasification kinetic parameters. The FWO method exhibited the best fit to the experimental results. The pre-exponential factor was estimated using the Kissinger’s expression. The average apparent activation energy (E) for the char-gasification step was found to be 218.27 (SD), 143.70 (PP) and 87.89 kJ mol−1 (OP). The pre-exponential factors were 6.93 1023 (SD), 5.10 1014 (PP), and 3.71 1009 s−1 (OP). A kinetic model to predict the CO release during the bio-waste decomposition was also proposed and validated. The E values for global release of CO were 87.34 (SD), 67.19 (PP), and 133.23 kJ mol−1 (OP). In addition, the thermodynamic parameters ΔS, ΔH and ΔG were calculated from the FWO method. The positive values of ΔH evidenced the global endothermicity of the gasification process over the whole range of the conversion degree. The average ΔG values were 130.53 (SD), 148.17 (PP) and 132.91 kJ mol−1 (OP). The average ΔS and ΔG values, together with the Arrhenius kinetic coefficient showed that the reactivity for gasification decreased in the following order: SD > OP > PP. The results are in good agreement with previously reported data.

Kinetic analysis and thermodynamics properties of air/steam gasification of agricultural waste

Isoconversional methods are commonly used to process the thermogravimetric analysis (TGA) data and to simultaneously obtain the effective activation energies for lignocellulosic biomass pyrolysis. ...

Insight into Pyrolysis Kinetics of Lignocellulosic Biomass: Isoconversional Kinetic Analysis by the Modified Friedman Method

Background Lymph-vascular space invasion (LVSI) is an unfavorable prognostic factor in cervical cancer. Unfortunately, there are no current clinical tools for the preoperative prediction of LVSI. Purpose To develop and validate an axial T1 contrast-enhanced (CE) MR-based radiomics nomogram that incorporated a radiomics signature and some clinical parameters for predicting LVSI of cervical cancer preoperatively. Study type Retrospective. Population In all, 105 patients were randomly divided into two cohorts at a 2:1 ratio. Field strength/sequence T1 CE MRI sequences at 1.5T. Assessment Univariate analysis was performed on the radiomics features and clinical parameters. Multivariate analysis was performed to determine the optimal feature subset. The receiver operating characteristic (ROC) analysis was performed to evaluate the performance of prediction model and radiomics nomogram. Statistical tests The Mann-Whitney U-test and the chi-square test were used to evaluate the performance of clinical characteristics and LVSI status by pathology. The minimum-redundancy/maximum-relevance and recursive feature elimination methods were applied to select the features. The radiomics model was constructed using logistic regression. Results Three radiomics features and one clinical characteristic were selected. The radiomics nomogram showed favorable discrimination between LVSI and non-LVSI groups. The AUC was 0.754 (95% confidence interval [CI], 0.6326-0.8745) in the training cohort and 0.727 (95% CI, 0.5449-0.9097) in the validation cohort. The specificity and sensitivity were 0.756 and 0.828 in the training cohort and 0.773 and 0.692 in the validation cohort. Data conclusion T1 CE MR-based radiomics nomogram serves as a noninvasive biomarker in the prediction of LVSI in patients with cervical cancer preoperatively. Level of evidence 4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:1420-1426.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/jmri.26531

MR-Based Radiomics Nomogram of Cervical Cancer in Prediction of the Lymph-Vascular Space Invasion preoperatively.

Pyrolytic degradation of peanut shell: Activation energy dependence on the conversion.

The pyrolysis process of various types of biomass (agricultural and wood by-products) in non-isothermal conditions using simultaneous thermal analyses (STA) was investigated. Devolatilization kinetics was implemented through combined application of model-free methods and DAEM (distributed activation energy model) using Gaussian distribution functions of activation energies. Results obtained were used in the curve prediction of the rate of mass loss against temperature at various heating rates by numerical optimization. The possible calculation of biomass samples behavior under pyrolytic conditions as the summation of their pseudo-components, hemicelluloses, cellulose, and lignin is also explored. The differences between experimental and calculated data are less than 3.20% offering a quality test of applicability of proposed model on the kinetic studies of a wide range of biomass samples. It seems that the most physically realistic model is the decomposition of biomass in three reactions, depending on the composition of the biomass regarding hemicelluloses, cellulose, and lignin. Kinetic model applied here may serve as a starting point to build more complex models capable of describing the thermal behavior of plant materials during thermochemical processing.

/pdf/comparative-pyrolysis-kinetics-of-various-biomasses-based-on-1ci14zo47b.pdf

Comparative pyrolysis kinetics of various biomasses based on model-free and DAEM approaches improved with numerical optimization procedure

Improved TGA-MS measurements for evolved gas analysis (EGA) during pyrolysis process of various biomass feedstocks. Syngas energy balance determination

Background Considering the morbidity of radical hysterectomy, the advent of fertility-sparing approaches, and the low risk of parametrial involvement in patients with early stage I cervical tumors, the benefit from parametrial resection is debatable. Objectives of this study were to determine factors predicting parametrial tumor spread and to define a group of patients who might be safely spared parametrial resection. Methods Pathology review was done on patients with stages IA2 and small IB1, treated by radical hysterectomy and pelvic lymph node dissection. Analysis was performed to determine factors associated with parametrial spread and to define risks of obeying parametrial resection. Results A total of 223 patients with tumors less than 20 mm in diameter were identified. Parametrial metastases were documented in 8 patients (3.6%); nodes, 1.3%; lymphovascular space invasion (LVSI), 1.8%; contiguous spread, 0.9%. Of 211 (94.6%) patients with negative pelvic nodes, none had parametrial nodal involvement, 0.9% had LVSI, and 0.4% had contiguous spread. Factors associated with parametrial disease were deep cervical invasion, LVSI, tumor volume, and pelvic lymph node metastases (P Conclusions Our data show a risk of parametrial spread of 0.45% for tumors less than 20 mm in diameter, no LVSI, and a depth of invasion within the inner third. Patients wanting fertility preservation might be prepared to take this risk of recurrence. Morbidity after nerve-sparing radical hysterectomy is tolerably low, and for patients in whom fertility preservation is not an issue, this should be considered the standard of care.

https://ijgc.bmj.com/content/ijgc/26/2/416.full.pdf

Risk of Parametrial Spread in Small Stage I Cervical Carcinoma: Pathology Review of 223 Cases With a Tumor Diameter of 20 mm or Less.

The detailed kinetic analysis of slow pyrolysis process of apricot (Prunus armeniaca L.) kernal shells has been estimated, under non-isothermal conditions, through thermogravimetric analysis and derivative thermogravimetry. Thermal decomposition was implemented using four different heating rates (5, 10, 15, and 20°C per minute), with consideration of how this parameter effects on the process kinetics. The higher heating rates provoke the shift of thermoanalytical curves towards more elevated temperatures. Using isoconversional differential method, the variation of activation energy, Ea, with conversion fraction, α, was detected, and pyrolysis reaction profile was discussed. After resolving the pyrolysis rate curves of individual biomass constituents, the temperature and conversion ranges of their thermal transformations were clearly identified. In the latter stage of analysis, every identified reaction step was considered through mechanistic description, which involves selection of the appropriate kinetic model function. The comparison of the results as well as discrepancies between them has been discussed. The corresponding rate-law equations related to thermal decomposition reactions of all biomass constituents present in the tested agricultural waste material have been identified.

/pdf/thermogravimetric-study-on-the-pyrolysis-kinetic-mechanism-3ojwbmneko.pdf

Thermogravimetric study on the pyrolysis kinetic mechanism of waste biomass from fruit processing industry

In the Republic of Serbia there are significant quantities of coffee and tire wastes that can be utilized as Solid Recovered Fuel (SRF) and used as an additional fuel for co–combustion with coal and biomass in energy production and cement industry sectors. Differences between SRF and base fuel are cause of numerous problems in design of burners. The objective of this study was to determine the kinetic parameters for the thermochemical conversion of selected SRF using Simultaneous Thermal Analysis (STA). Samples of coffee and tire waste were used for the experimental tests. Thermal analysis was carried out in nitrogen atmosphere at three different heating rates 10, 15 and 20 K/min for each sample, while it was heated from room temperature up to 900°C. Two sample sizes x <0.25 mm and 0.25 < x <0.5 mm of each SRF were used in experiments, in order to obtain reliable Thermal Gravimetric Analysis (TGA) data for estimation of kinetic parameters for SRF pyrolysis. Experimental results were used for determination of pre-exponential factor and activation energy according to methods presented in the literature. Presented research provide valuable data of coffee and tire waste, that can be used for the burners design.

/pdf/thermogravimetric-kinetic-study-of-solid-recovered-fuels-24qd7begci.pdf

Miloš Radojević

Papers

Comparative pyrolysis kinetics of various biomasses based on model-free and DAEM approaches improved with numerical optimization procedure

Improved TGA-MS measurements for evolved gas analysis (EGA) during pyrolysis process of various biomass feedstocks. Syngas energy balance determination

Risk of Parametrial Spread in Small Stage I Cervical Carcinoma: Pathology Review of 223 Cases With a Tumor Diameter of 20 mm or Less.

Thermogravimetric study on the pyrolysis kinetic mechanism of waste biomass from fruit processing industry

Thermogravimetric kinetic study of solid recovered fuels pyrolysis