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Effect of Processing and Cultivar on Thermo-Chemical Properties of Australian-Grown Hemp Hurd(Cannabis sativa L.)

Journal of Renewable Materials 2024年第8期12卷 1475-1493页

作者： johannes fehrmann Benoit Belleville Barbara Ozarska Maya Ismayati Wahyu Dwianto School of Agriculture Food and Ecosystem Sciences(SAFES)Faculty of ScienceThe University of MelbourneMelbourne3121Australia Research Center for Biomass and Bioproducts National Research and Innovation Agency(BRIN)Jakarta16911Indonesia

This study explored the thermo-chemical properties of industrial hemp hurd with different provenances,maturity stages,and retting *** findings were then compared to hemp hurd used in the fabrication of citric acid-bonded ultra-low-density hemp hurd ***-gas chromatography-mass spectrometry(Py-GC/MS),Fourier-transform infrared spectroscopy(FTIR),and thermogravimetric analysis(TGA)were employed to document the variability of the hurd and comprehend the potential impact on biobased composite *** choice of cultivar,maturity stage,and processing modality significantly influenced the chemical composition,presence of functional groups,and thermal stability of the ***-GC/MS revealed substantial variations in the lignin-to-carbohydrate(L/C)ratio,along with the absence of fatty acids in certain *** FTIR signals confirmed consistent functional groups,differences in peak intensities were indicative of carbohydrate variations associated with maturity and retting duration,impacting the availability of hydroxyl groups for,i.e.,interparticle bonding in citric acid-based ***,it was observed that shorter retting durations initially enhanced the thermal resistance,but prolonged retting led to accelerated degradation,significantly reducing the hurd’s residual *** findings indicated notable differences among the samples,emphasizing the importance of investigating variables such as provenance/cultivar,maturity,and processing *** assessment is essential to ensure effective agronomic practices that align the raw material characteristics with the specific requirements of intended applications,such as the fabrication of biobased hemp hurd composites.

关键词： Hemp hurd material characterization chemical analysis thermal analysis

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Comparison of estimators of variance for forest inventories with systematic sampling-results from artificial populations

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Forest Ecosystems 2020年第2期7卷 215-233页

作者： Steen Magnussen Ronald EMcRoberts johannes Breidenbach Thomas Nord-Larsen Göran Ståhl Lutz fehrmann Sebastian Schnell 506 West Burnside Road VictoriaBC V8Z 1M5Canada Raspberry Ridge Analytics 15111 Elmcrest Avenue NorthHugoMN 55038USA Norwegian Institute of Bioeconomy Research Høgskolevegen 81431ÅsNorway Department of Geosciences and Natural Resource Management University of CopenhagenRolighedsvej 23DK-1958 Frederiksberg CDenmark Department of Forest Resource Management Swedish University of Agricultural SciencesUmeåSweden Forest Inventory and Remote Sensing Faculty of Forest SciencesUniversity of GöttingenBüsgenweg 5D37077GöttingenGermany Alfred-Möller-Straße 1 Haus 41-4216225 EberswaldeGermany.

Background:Large area forest inventories often use regular grids(with a single random start)of sample locations to ensure a uniform sampling intensity across the space of the surveyed populations.A design-unbiased estimator of variance does not exist for this ***,a quasi-default estimator applicable to simple random sampling(SRS)is used,even if it carries with it the likely risk of overestimating the variance by a practically important *** better exploit the precision of systematic sampling we assess the performance of five estimators of variance,including the quasi *** this study,simulated systematic sampling was applied to artificial populations with contrasting covariance structures and with or without linear *** compared the results obtained with the SRS,Matern’s,successive difference replication,Ripley’s,and D’Orazio’s variance ***:The variances obtained with the four alternatives to the SRS estimator of variance were strongly correlated,and in all study settings consistently closer to the target design variance than the estimator for *** latter always produced the greatest *** populations with a near zero spatial autocorrelation,all estimators,performed equally,and delivered estimates close to the actual design ***:Without a linear trend,the SDR and DOR estimators were best with variance estimates more narrowly distributed around the benchmark;yet in terms of the least average absolute deviation,Matern’s estimator held a narrow *** a strong or moderate linear trend,Matern’s estimator is *** large populations,and a low sampling intensity,the performance of the investigated estimators becomes more similar.

关键词： Spatial autocorrelation Linear trend Model based Design biased Matern variance Successive difference replication variance Geary contiguity coefficient Random site effects

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