scholarly journals Penetration of urea-formaldehyde adhesives in wood tissue, part I: Radial penetration of UF adhesives into beech

2008 ◽  
pp. 39-48 ◽  
Author(s):  
Ivana Gavrilovic-Grmusa ◽  
Jovan Miljkovic ◽  
Milanka Djiporovic-Momcilovic ◽  
Gordana Radosevic
Keyword(s):  
Urea Formaldehyde ◽  
Beech Wood ◽  
Processing Parameters ◽  
Hydraulic Press ◽  
Wood Industry ◽  
Cross Sectional ◽  
Wood Tissue ◽  
Adhesive Penetration ◽  
Sectional Surface ◽  
Different Levels

Adhesive penetration plays an important role in wood adhesion, since wood is a porous material. The degree of penetration mostly depends on the wood factors, resin type and formulation and processing parameters. Tangentially cut 5 mm thick beech wood (Fagus moesiaca) plies, 100 mm long (parallel to grain) and 30 mm wide, were prepared for this study. The urea-formaldehyde (UF) adhesive was applied to the surface of one ply. Two plies were assembled into sample so that the grains of two plies were parallel. Samples were pressed in a hydraulic press at 120?C and 0,7 MPa for 15 min. Microtome test-specimens were cut of each sample. 20 ?m thick microtomes were cut by sliding microtome apparatus, exposing a bondline with a cross-sectional surface. The lack of more exhausting research on the penetration of urea-formaldehyde adhesives in wood is evident. Since ureaformaldehyde (UF) glue resins were the most important type of adhesives in the wood industry in the last 60 years (Dunky, 2000), the objective of this research was microscopic detection of UF adhesive penetration in wood tissue. Four types of UF resins with different levels of polycondensation were used in this research. Safranin was added in resins, since epi-fluorescence microscope was used in this research for measuring the adhesive penetration.

scholarly journals Penetration of urea formaldehyde adhesives in wood tissue, Part II: Radial penetration of UF adhesives into silver fir

2009 ◽  
pp. 33-42 ◽  
Author(s):  
Ivana Gavrilovic-Grmusa ◽  
Jovan Miljkovic ◽  
Milanka Djiporovic-Momcilovic ◽  
Gordana Radosevic
Keyword(s):  
Substrate Surface ◽  
Urea Formaldehyde ◽  
Abies Alba ◽  
Hydraulic Press ◽  
Silver Fir ◽  
Cross Sectional ◽  
Wood Tissue ◽  
Adhesive Penetration ◽  
Sectional Surface ◽  
Degree Of Condensation

Penetration is the ability of the adhesive to move into the voids on the substrate surface or into the substrate itself. Wood's cellular nature allows significant penetration of the adhesive into the substrate. Objective of this work was the evaluation of the penetration and hence the distribution of urea-formaldehyde (UF) resins by means of microscopic detection of the penetration of such UF adhesives into the wood tissue. Tangentially cut 5 mm thick silver fir (Abies alba Mill.) plies, 100 mm long (parallel to the grain) and 30 mm width, were prepared for this study. Four types of UF resins with different degree of condensation were investigated in this research. Safranin was added to the resins and epi-fluorescence microscope was used for measuring the adhesive penetration. The UF adhesive mixes, consisting of the various resins, extender and hardener were applied to the surface of one ply. Two plies, one with applied adhesive mix and one without adhesive mix, were assembled with parallel grain direction. Samples were pressed in a hydraulic press at 120?C and 1.0 MPa for 15 minutes. Test-specimens of 20 ?m thickness were cut of each sample using a sliding microtome apparatus, exposing a bondline on a cross-sectional surface. The results show a significant correlation between the penetration behaviour and the degree of condensation (molecular sizes, viscosity) of the resins. The higher the degree of condensation, the lower the possibility for penetration, expresses as average penetration (AP) and as portion of filled tracheids on the whole cross section of interphase (filled interphase region FIR).

scholarly journals Circulating bioactive sclerostin levels in an Austrian population-based cohort

2021 ◽  
Author(s):  
Katharina Kerschan-Schindl ◽  
Ursula Föger-Samwald ◽  
Andreas Gleiss ◽  
Stefan Kudlacek ◽  
Jacqueline Wallwitz ◽  
...  
Keyword(s):  
Serum Levels ◽  
Population Based ◽  
Negative Regulator ◽  
Total Serum ◽  
Mineral Density ◽  
Cross Sectional ◽  
Robust Parameter ◽  
Austrian Population ◽  
Different Levels

Summary Background Circulating serum sclerostin levels are supposed to give a good estimation of the levels of this negative regulator of bone mass within bone. Most studies evaluating total serum sclerostin found different levels in males compared to females and in older compared to younger subjects. Besides an ELISA detecting total sclerostin an ELISA determining bioactive sclerostin has been developed. The aim of this study was to investigate serum levels of bioactive sclerostin in an Austrian population-based cohort. Methods We conducted a cross-sectional observational study in 235 healthy subjects. Using the bioactive ELISA assay (Biomedica) bioactive sclerostin levels were evaluated. Results Serum levels of bioactive sclerostin were higher in men than in women (24%). The levels correlated positively with age (r = 0.47). A positive correlation could also be detected with body mass index and bone mineral density. Conclusion Using the ELISA detecting bioactive sclerostin our results are consistent with data in the literature obtained by different sclerostin assays. The determination of sclerostin concentrations in peripheral blood thus appears to be a robust parameter of bone metabolism.

scholarly journals AB0499 PHYSICAL ACTIVITY ASSESSMENT IN TUNISIAN PATIENTS WITH SPONDYLOARTHRITIS: THE IPAQ EVALUATION

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1277.1-1277
Author(s):  
F. Majdoub ◽  
M. Sellami ◽  
S. Miladi ◽  
A. Fazaa ◽  
L. Souabni ◽  
...  
Keyword(s):  
Physical Activity ◽  
Disease Activity ◽  
Axial Spondyloarthritis ◽  
Cross Sectional Study ◽  
Urban Setting ◽  
Tnf Inhibitor ◽  
Sectional Study ◽  
Cross Sectional ◽  
Tunisian Patients ◽  
Different Levels

Background:The occurrence of Spondyloarthritis (SpA) often conditions patients’ quality of life and hinders their well-being. Physical activity (PA) is associated with various health-related benefits among adults with chronic inflammatory rheumatism but may be insufficiently performed.Objectives:This study aimed to assess PA in patients with SpA and explore its associated factors.Methods:This is a single-center cross-sectional study, involving patients with SpA, visiting our outpatient hospital over eight weeks. Patients responded to the International Physical Activity Questionnaire-Short form (IPAQ-S).Results:Sixty patients were included (39 M/21 F) with an average age of 45.8 years [25-78]. The mean duration of SpA was 13.2 years [1-25]. About 80% of patients were from an urban setting. Sixty-three percent of patients had a professional activity, while 13.3% were retired. Twenty-nine patients (48.3%) had axial and peripheral form, 18 patients (30%) had SpA with enteropathic arthritis, 8 (13.3%) with psoriatic arthritis, 3 patients (5%) had axial spondyloarthritis, and only 2 patients (3.3%) with SAPHO-Syndrom. About 23% of patients had hip arthritis and only 5% had uveitis. Fifty-eight patients were on TNF-inhibitor (21/58 Adalimumab, 15/58 Infliximab, 14/58 Etanercept, 8/58 Golimumab). The average BASDAI was 2.7/10. The average ASDASCRP was 2.1/10. The average BASFI was 3.3/10. IPAQ results were distributed as follows: 78.3% of patients were in the « low physical activity » category, 21.7% were in the « moderate physical activity » while none of the patients were in the « high physical activity ». Patients without employment had lower levels of physical activity (29.7%) but no association was observed between those two items (p=0.082). Disease activity objectified with BASDAI was related to low physical activity (p=0.045) whereas no association was observed with ASDASCRP (p=0.870) or BASFI (p=0.056). Otherwise, TNF-inhibitor treatment was not related to different levels of PA (p=0.09).Conclusion:Tunisian patients with SpA don’t perform enough physical activity. Except for high disease activity, the different levels of PA did not appear to be explained by other disease-related variables. Thereby, physical activity should be encouraged in SpA.References:[1]Fabre, S., Molto, A., Dadoun, S. et al. Physical activity in patients with axial spondyloarthritis: a cross-sectional study of 203 patients. Rheumatol Int 36, 1711–1718 (2016).Disclosure of Interests:None declared.

scholarly journals Six ultraviolet minutes for cleaner operating theatres

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
R Bosco ◽  
S Gambelli ◽  
V Urbano ◽  
G Cevenini ◽  
G Messina
Keyword(s):  
Cross Sectional Study ◽  
Cross Sectional ◽  
Before And After ◽  
Operating Theatres ◽  
Cleaning Procedures ◽  
The Difference ◽  
Contamination Levels ◽  
Different Levels ◽  
Better Than ◽  
Final Cleaning

Abstract Background Sanitizing the operating theatres (OT) is important to minimize risk of post-operative infections. Disinfection procedures between one operation and another is less aggressive than final cleaning procedures, at the end of the day. Aim was assessing the difference of contamination: i) between different levels of disinfection; ii) before and after the use of a UVC Device (UVC-D). Methods Between December 2019/February 2020 a cross sectional study was conducted in OT in a real clinical context. 94 Petri dishes (PD) were used in 3 OT. Three different sanitation levels (SL1-3) were compared pre- and post-use of UVC-D: i) No cleaning after surgery (SL1); ii) after in-between cleaning (SL2); iii) after terminal cleaning (SL3). UVC-D was employed for 6 minutes, 3 minutes per bed side. PD were incubated at 36 °C and colony forming unit (CFU) counted at 48h. Descriptive statistic, Wilcoxon and Mann-Whitney tests were performed to assess the contamination levels in total, pre/post use of UVC-D, and between different sanitation levels, respectively. Results In total we had a mean of 3.39 CFU/PD (C.I. 2.05 - 4.74) and a median of 1 CFU/PD (Min. 0 - Max. 39), after UVC-D use we had a mean of 2.20 CFU/PD (C.I. 0.69 - 5.09) and a median of 0 CFU/PD (Min. 0 - Max. 133). The UVC-D led to a significant reduction of CFU (p < 0.001). Without UVC-D we had a significant CFU drop (p < 0.05) between SL1 and SL3. Using UVC-D, we observed significant reductions of contamination (p < 0.05) between SL3 and SL1. Comparing SL1 (median 0) post UVC-D use vs SL2 pre UVC-D use (median 0.5), and SL2 post UVC-D use (median 0) vs SL3 pre UVC-D use (median 1) we had a significant reduction of contamination (p < 0.05). Conclusions UVC-D improved environmental contamination in any of the three sanitation levels. Furthermore, the use of UVC-D alone was better than in-between and terminal cleaning. Although these encouraging results, the cleaning procedures executed by dedicated staff has to be considered. Key messages UVC are efficient to decrease contamination in operating theatres regardless of sanitation levels. The additional use of UVC technology to standard cleaning procedures significantly improves sanitation levels.

Variations in the Compression Strength of Cylindrical Samples Made of Dense Hydroxyapatite

2007 ◽  
Vol 361-363 ◽  
pp. 103-106 ◽  
Author(s):  
Sergey V. Dorozhkin ◽  
Oguzhan Gunduz ◽  
Faik N. Oktar
Keyword(s):  
Ambient Temperature ◽  
Compression Strength ◽  
Total Mass ◽  
Processing Parameters ◽  
Hydraulic Press ◽  
Geometrical Dimensions ◽  
Cylindrical Samples ◽  
Spray Dried

Dense bioceramics made of pure hydroxyapatite (HA) was prepared and characterized. The cylindrical samples were compacted from HA powders of diverse pretreatments; namely, from spray-dried HA, calcined HA and mixtures thereof. The samples were prepared by a hydraulic press under different compaction loads both with and without auxiliary compounds (a binder and a lubricant). Both the total mass and geometrical dimensions of the prepared cylinders were measured. Then, the cylindrical samples were sintered at 1200 °C for 4 hours. After cooling down to ambient temperature, the sintered cylinders were weighed and their geometrical dimensions were measured once again. Mass decreasing and the shrinkage degree were calculated as a result. Afterwards, the compression strength of the sintered cylinders was measured by an Instron 5587 machine. Preparation of dense HA bioceramics possessing the highest possible compression strength was the purpose of this study. The necessary processing parameters were discovered.

Sensor Fusion and On-Line Monitoring of Friction Stir Blind Riveting for Lightweight Materials Manufacturing

2021 ◽  
pp. 1-36
Author(s):  
Zhe Gao ◽  
Haris Khan ◽  
Jingjing Li ◽  
Weihong Guo
Keyword(s):  
Sensor Fusion ◽  
Failure Modes ◽  
Processing Parameters ◽  
Data Driven ◽  
Structure Property ◽  
Cross Sectional ◽  
Friction Stir ◽  
In Situ Data ◽  
Lap Shear

Abstract This research focused on developing a hybrid quality monitoring model through combining the data driven and key engineering parameters to predict the friction stir blind riveting (FSBR) joint quality. The hybrid model was formulated through utilizing the in-situ processing and joint property data. The in-situ data involved sensor fusion (force and torque signals) and key processing parameters (spindle speed, feed rate and stacking sequence) for data-driven modeling. The quality of the FSBR joints was defined by the tensile strength. Further, the joint cross-sectional analysis and failure modes in lap-shear tests were employed to confirm the efficacy of the proposed model and development of the process-structure-property relationship.

Effect of Substrate Temperature on Properties of Nano-Scale Functionally Graded Calcium Phosphate Coatings

2006 ◽  
Author(s):  
Travis Blalock ◽  
Xiao Bai ◽  
Afsaneh Rabiei
Keyword(s):  
Electron Microscopy ◽  
Calcium Phosphate ◽  
Substrate Temperature ◽  
Ion Beam ◽  
Processing Parameters ◽  
Functionally Graded ◽  
Cross Sectional ◽  
X Ray ◽  
Phosphate Coatings ◽  
Calcium Phosphate Coatings

The effect of substrate temperature and processing parameters on microstructure and crystallinity of calcium phosphate coatings deposited on heated substrates in an Ion Beam Assisted Deposition (IBAD) system are being studied. The experimental procedures include mechanical testing and film thickness measurements using bonding strength and profilometery. Cross-sectional scanning transmission electron microscopy (STEM) with energy dispersive X-ray spectroscopy (EDX) through the thickness of the film as well as scanning electron microscopy (SEM) with EDX at the top surface of the film was performed to evaluate the microstructure of the film. The coating crystallinity was studied through X-ray diffraction (XRD). The information gained from current analysis on the set temperature coatings will be used to refine the processing techniques of the Functionally Graded Hydroxyapatite (FGHA) coating.

Formation of the Cast Iron Coatings Plasma-Sprayed at Different Substrate Temperatures

2010 ◽  
Vol 44-47 ◽  
pp. 2144-2147
Author(s):  
Ya Zhe Xing ◽  
Chao Ping Jiang ◽  
Hong Chen ◽  
Jian Min Hao
Keyword(s):  
Cast Iron ◽  
Substrate Temperature ◽  
Phase Structure ◽  
Processing Parameters ◽  
Optical Microscope ◽  
Atmospheric Plasma ◽  
Cross Sectional ◽  
The Cross ◽  
Plasma Sprayed ◽  
Iron Coatings

In this work, three cast iron coatings were produced by atmospheric plasma spraying. During spraying, the surface temperature of three coatings (substrate temperature) was controlled to be averagely 50oC, 180oC and 240oC by changing the processing parameters. X-ray diffraction (XRD) was employed to analyze the phase structure of the starting powder and the coatings. The results showed that the powder was mainly composed of (Fe,Cr)7C3 and martensite and both the spraying processing and the substrate temperature exerted no influence on coating phase structure. An optical microscope (OM) was used to characterize the microstructure of the cross-section and surface of the coatings. It was found that the cross sectional hardness increased with the increase of the substrate temperature due to the improvement in interlamellar bonding.

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