Nucleation in medium density polyethylenes: comparisons between metallocene and chromium catalysts

2000 ◽  
Vol 49 (11) ◽  
pp. 1329-1337 ◽  
Author(s):  
J?J Janimak ◽  
G?C Stevens
Keyword(s):  
Medium Density ◽  
Chromium Catalysts

scholarly journals Calcium carbonate modified urea–formaldehyde resin adhesive for strength enhanced medium density fiberboard production

RSC Advances ◽  
2021 ◽  
Vol 11 (40) ◽  
pp. 25010-25017
Author(s):  
Li Lu ◽  
Yan Wang ◽  
Tianhua Li ◽  
Supeng Wang ◽  
Shoulu Yang ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Urea Formaldehyde ◽  
Medium Density Fiberboard ◽  
Urea Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Medium Density ◽  
Ionic Bond ◽  
Resin Adhesive ◽  
Uf Resin ◽  
Modified Urea

Reactions between CaCO3 and CH2O2 during polycondensation of UF resin produce Ca2+. Ionic bond complexation binds Ca2+ with UF resin. The UF resin crystalline percentage decreases from 26.86% to 22.71%. IB strength of resin bonded fiberboard increases from 0.75 to 0.94 MPa.

scholarly journals A SNP assay for assessing diversity in immune genes in the honey bee (Apis mellifera L.)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dora Henriques ◽  
Ana R. Lopes ◽  
Nor Chejanovsky ◽  
Anne Dalmon ◽  
Mariano Higes ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Honey Bee ◽  
Large Scale ◽  
Medium Density ◽  
Nucleotide Polymorphisms ◽  
Functional Variation ◽  
Immune Genes ◽  
Wide Range ◽  
Scale Range ◽  
Innate Immune Genes

AbstractWith a growing number of parasites and pathogens experiencing large-scale range expansions, monitoring diversity in immune genes of host populations has never been so important because it can inform on the adaptive potential to resist the invaders. Population surveys of immune genes are becoming common in many organisms, yet they are missing in the honey bee (Apis mellifera L.), a key managed pollinator species that has been severely affected by biological invasions. To fill the gap, here we identified single nucleotide polymorphisms (SNPs) in a wide range of honey bee immune genes and developed a medium-density assay targeting a subset of these genes. Using a discovery panel of 123 whole-genomes, representing seven A. mellifera subspecies and three evolutionary lineages, 180 immune genes were scanned for SNPs in exons, introns (< 4 bp from exons), 3’ and 5´UTR, and < 1 kb upstream of the transcription start site. After application of multiple filtering criteria and validation, the final medium-density assay combines 91 quality-proved functional SNPs marking 89 innate immune genes and these can be readily typed using the high-sample-throughput iPLEX MassARRAY system. This medium-density-SNP assay was applied to 156 samples from four countries and the admixture analysis clustered the samples according to their lineage and subspecies, suggesting that honey bee ancestry can be delineated from functional variation. In addition to allowing analysis of immunogenetic variation, this newly-developed SNP assay can be used for inferring genetic structure and admixture in the honey bee.

scholarly journals Repeated thermo-hydrolytic disintegration of medium density fibreboards (MDF) for the production of new MDF

2021 ◽  
Author(s):  
Fahriye Yağmur Bütün Buschalsky ◽  
Carsten Mai
Keyword(s):  
Service Life ◽  
Nitrogen Content ◽  
Manufacturing Process ◽  
Closed Loop ◽  
Reducing Sugars ◽  
Urea Formaldehyde ◽  
Molar Ratio ◽  
Medium Density ◽  
Target Density ◽  
Formaldehyde Content

AbstractMedium density fibreboards (MDF) are currently not recycled after service life, but various publications report on recycling by the disintegration of MDF using various techniques and the properties of obtained recovered fibres (RF). In this study, the main aim was to put back RF into the MDF manufacturing process as closed-loop recycling using repeated thermo-hydrolytic disintegration. Compared to previous studies, the focus was on the recycling of MDF with a relatively low F:U molar ratio (1.11). Urea–formaldehyde-bonded MDF with a target density of 700 kg m−3 was subjected to thermo-hydrolytic disintegration in an autoclave using only water at 95 °C for 20–30 min. Afterwards, the properties of RF and virgin fibres (VF), of MDF produced thereof and the composition of the disintegration water (DW) were determined. The nitrogen content (NC) revealed that RF contained about 30% of the initially applied UF. The pH of the DW hardly changed during recycling and it contained considerable amounts of reducing sugars. Using RF did not result in higher formaldehyde emissions than VF. Compared to earlier studies using a higher formaldehyde content (higher F:U ratio), MDF bonded with modern UF resins can be disintegrated under clearly milder disintegration conditions with respect to temperature and time. The properties of recycled MDF were similar to those of reference MDF; up to 100% RF could be used without severely deteriorating the strength and increasing formaldehyde emissions from these panels.

Medium density boards made of groundwood fibres: an analysis of their mechanical and physical properties

2018 ◽  
Vol 77 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Sauro Bianchi ◽  
Heiko Thömen ◽  
Stefan Junginger ◽  
Frédéric Pichelin
Keyword(s):  
Physical Properties ◽  
Medium Density ◽  
Mechanical And Physical Properties

Medium Density Particleboard with Addition of Impregnated Paper

2014 ◽  
Vol 1025-1026 ◽  
pp. 543-546
Author(s):  
Juliana Cortez Barbosa ◽  
Anderson Luiz da Silva Michelon ◽  
Elen Aparecida Martines Morales ◽  
Cristiane Inácio de Campos ◽  
André Luis Christoforo ◽  
...  
Keyword(s):  
Moisture Content ◽  
Modulus Of Elasticity ◽  
Mechanical Tests ◽  
Modulus Of Rupture ◽  
Medium Density ◽  
Test Results ◽  
Thickness Swelling ◽  
Adhesion Test ◽  
Layer Medium ◽  
Determine Moisture Content

The aim of this research was to produce three-layer Medium Density Particleboard (MDP), with the addition of impregnated paper, in the inner layer, in proportions of 1; 5 and 20%. In this study, MDP was composed with particles of small size in outer layers, and larger particles in internal layer. After panel manufacturing, physical and mechanical tests based on Brazilian Code ABNT NBR 14.810 were carried out to determine moisture content; density; thickness swelling; water absorption; modulus of rupture (MOR) and modulus of elasticity (MOE) in static bending and internal adhesion. Test results were compared to commercial panels, produced with 100% Eucalyptus, considering the requirements specified by Brazilian Code. Properties presented values close to normative specifications, indicating positively the possibility of production of MDP using addition of waste paper impregnated.

scholarly journals Medium Density Fibreboard Made from Kenaf (Hibiscus cannabinus L.) Stem: Effect of Thermo-mechanical Refining and Resin Content

BioResources ◽  
2014 ◽  
Vol 9 (2) ◽  
Author(s):  
Majid Dehghan Nayeri ◽  
Paridah Md Tahir ◽  
Mohammad Jawaid ◽  
Zaidon Ashaari ◽  
Luqman Chuah Abdullah ◽  
...  
Keyword(s):  
Resin Content ◽  
Hibiscus Cannabinus ◽  
Medium Density ◽  
Medium Density Fibreboard ◽  
Mechanical Refining
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