scholarly journals Influence of Impregnation with Modified Starch of a Paper Core on Bending of Wood-Based Honeycomb Panels in Changing Climatic Conditions

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 395
Author(s):  
Michał Słonina ◽  
Dorota Dziurka ◽  
Marta Molińska-Glura ◽  
Jerzy Smardzewski
Keyword(s):  
Mechanical Properties ◽  
Statistical Analysis ◽  
Significant Relationship ◽  
Climatic Conditions ◽  
Bending Test ◽  
Modified Starch ◽  
Air Humidity ◽  
Absorbed Energy ◽  
Three Point Bending ◽  
Relative Air Humidity

The main objective of the study was to determine the effect of impregnation of the paper core with acetylated starch on the mechanical properties and absorbed energy in the three-point bending test of wood-based honeycomb panels under varying temperatures and relative air humidity conditions. Nearly six hundred beams in various combinations, three types of facings, three core cells geometries, and two paper thicknesses were tested. The experiment results and their statistical analysis prove a significant relationship between the impregnation of paper with modified starch and mechanical properties. The most effective in absorbing energy, the honeycomb panels, consisted of a core with a wall thickness of 0.25 mm and a particleboard facing.

Influence of Honeycomb Core Compression on the Mechanical Properties of the Sandwich Structure

2013 ◽  
Vol 486 ◽  
pp. 283-288
Author(s):  
Ladislav Fojtl ◽  
Soňa Rusnáková ◽  
Milan Žaludek
Keyword(s):  
Mechanical Properties ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Low Velocity Impact ◽  
Bending Test ◽  
Honeycomb Core ◽  
Low Velocity ◽  
Three Point Bending ◽  
Core Technology

This research paper deals with an investigation of the influence of honeycomb core compression on the mechanical properties of sandwich structures. These structures consist of prepreg facing layers and two different material types of honeycomb and are produced by modified compression molding called Crush-Core technology. Produced structures are mechanically tested in three-point bending test and subjected to low-velocity impact and Charpy impact test.

Comparison of the Cross Sectional Area, the Loss in Volume and the Mechanical Properties of LAE442 and MgCa0.8 as Resorbable Magnesium Alloy Implants after 12 Months Implantation Duration

2010 ◽  
Vol 638-642 ◽  
pp. 675-680 ◽  
Author(s):  
Martina Thomann ◽  
Nina von der Höh ◽  
Dirk Bormann ◽  
Dina Rittershaus ◽  
C. Krause ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Degradation Process ◽  
Cross Sectional Area ◽  
Bending Test ◽  
Sectional Area ◽  
Cross Sectional ◽  
Initial Strength ◽  
Three Point Bending ◽  
The Cross

Current research focuses on magnesium based alloys in the course of searching a resorbable osteosynthetic material which provides sufficient mechanical properties besides a good biocompatibility. Previous studies reported on a favorable biocompatibility of the alloys LAE442 and MgCa0.8. The present study compared the degradation process of cylindrical LAE442 and MgCa0.8 implants after 12 months implantation duration. Therefore, 10 extruded implants (2.5 x 25 mm, cross sectional area 4.9 mm²) of both alloys were implanted into the medullary cavity of both tibiae of rabbits for 12 months. After euthanization, the right bone-implant-compound was scanned in a µ-computed tomograph (µCT80, ScancoMedical) and nine uniformly distributed cross-sections of each implant were used to determine the residual implants´ cross sectional area (Software AxioVisionRelease 4.5, Zeiss). Left implants were taken out of the bone carefully. After weighing, a three-point bending test was carried out. LAE442 implants degraded obviously slower and more homogeneously than MgCa0.8. The mean residual cross sectional area of LAE442 implants was 4.7 ± 0.07 mm². MgCa0.8 showed an area of only 2.18 ± 1.03 mm². In contrast, the loss in volume of LAE442 pins was more obvious. They lost 64 % of their initial weight. The volume of MgCa0.8 reduced clearly to 54.4 % which corresponds to the cross sectional area results. Three point bending tests revealed that LAE442 showed a loss in strength of 71.2 % while MgCa0.8 lost 85.6 % of its initial strength. All results indicated that LAE442 implants degraded slowly, probably due to the formation of a very obvious degradation layer. Degradation of MgCa0.8 implants was far advanced.

The influence of climatic conditions on physiological and behavioural parameters in dairy cows kept in open stables

2004 ◽  
Vol 78 (1) ◽  
pp. 139-147 ◽  
Author(s):  
M. Zähner ◽  
L. Schrader ◽  
R. Hauser ◽  
M. Keck ◽  
W. Langhans ◽  
...  
Keyword(s):  
Mean Value ◽  
Climatic Conditions ◽  
Air Humidity ◽  
Lactating Cows ◽  
Relative Air Humidity ◽  
Infra Red ◽  
Commercial Farms ◽  
Humidity Index ◽  
Body Surface Temperature ◽  
Night And Day

AbstractThis study aimed to assess whether cows are able to cope with the range of climatic conditions they are exposed to in open stables on commercial farms in central Europe. On each of four farms, ten lactating cows were observed over a total of five weeks in winter, spring and summer. Based on continuous measurements of air temperature (–13·8 to 28·7ºC) and relative air humidity (0·26 to 0·99), a mean value of a temperature humidity index (THI) was calculated for each farm and each observation day for night and day.THI had significant effects on skin temperature and body surface temperature (infra-red thermography) both during night and day. Rectal temperature, duration of lying and cortisol concentration in the milk was significantly affected by THI during the day but not during the night. Heart rate and frequency of lying did not significantly covary with THI. Differences between farms and interactions between THI and farm were significant for most parameters. These results suggest that the climatic conditions during the day induced stronger thermoregulatory responses than the conditions during the night. Within the measured range of climatic conditions the cows were hardly exposed to severe cold or heat stress.

THE INFLUENCE OF SiC COATING PROCESS ON THE PROPERTIES OF C/C COMPOSITES

2007 ◽  
Vol 14 (04) ◽  
pp. 817-820
Author(s):  
MIN HUANG ◽  
KE-ZHI LI ◽  
HE-JUN LI ◽  
QIAN-GANG FU ◽  
GUO-DONG SUN
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Failure Mode ◽  
Flexural Modulus ◽  
Pack Cementation ◽  
Bending Test ◽  
Carbon Composites ◽  
Coating Process ◽  
Three Point Bending ◽  
Coated Carbon

SiC coating for carbon/carbon composites was prepared by pack cementation method. The effects of coating process on the microstructure and the mechanical properties of C / C composites were analyzed by SEM and three-point bending test, respectively. As the infiltrated Si improved the interfaces bonding during the coating process, the flexural strength and flexural modulus of SiC -coated carbon/carbon composites were both increased by about 10% than the naked C / C composites. In addition, the mechanism of the change of failure mode of SiC coated C / C composites and naked C / C composites was addressed.

The Effect of the Compression on the Mechanical Properties of Wood Material

2007 ◽  
Vol 537-538 ◽  
pp. 41-46 ◽  
Author(s):  
László Kuzsella ◽  
Imre Szabó
Keyword(s):  
Mechanical Properties ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Bending Test ◽  
Wood Material ◽  
Ordinary Life ◽  
Three Point Bending ◽  
Wide Range ◽  
New Process ◽  
New Applications

The wood is one of the most favourable structural material. It appears on all fields of the ordinary life. It is difficult to say an application where the wood is not used due to its cheap price, availability and just simply the beauty. Beside of the wide range of process technologies a new process appeared. This process changes the properties of the material and brings many new applications to this traditional material. This process is the compression of the structural wood material. This publication deals with the effect of the compression on the mechanical properties of two hardwoods (beech: fagus sylvatica, oak: quercus) by the help of the three-point bending test and the Charpy impact test.

scholarly journals Influence of a Repeated Preheating Procedure on Mechanical Properties of Three Resin Composites

2015 ◽  
Vol 40 (2) ◽  
pp. 181-189 ◽  
Author(s):  
M D'Amario ◽  
F De Angelis ◽  
M Vadini ◽  
N Marchili ◽  
S Mummolo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Vickers Microhardness ◽  
Flexural Modulus ◽  
Bending Test ◽  
Resin Composites ◽  
Three Point Bending ◽  
Main Effect ◽  
Dependent Variables ◽  
Marginal Means

SUMMARY The aim of this study was to assess the flexural strength, flexural elastic modulus and Vickers microhardness of three resin composites prepared at room temperature or cured after one or repeated preheating cycles to a temperature of 39°C. Three resin composites were evaluated: Enamel Plus HFO (Micerium), Opallis (FGM), and Ceram X Duo (Dentsply DeTrey). For each trial, one group of specimens of each material was fabricated under ambient laboratory conditions, whereas in the other groups, the composites were cured after 1, 10, 20, 30, or 40 preheating cycles to a temperature of 39°C in a preheating device. Ten rectangular prismatic specimens (25 × 2 × 2 mm) were prepared for each group (N=180; n=10) and subjected to a three-point bending test for flexural strength and flexural modulus evaluation. Vickers microhardness was assessed on 10 cylindrical specimens from each group (N=180; n=10). Statistical analysis showed that, regardless of the material, the number of heating cycles was not a significant factor and was unable to influence the three mechanical properties tested. However, a significant main effect of the employed material on the marginal means of the three dependent variables was detected.

scholarly journals Influence of Temperature‑Humidity Relations During Years on Milk Production and Quality

2017 ◽  
Vol 65 (1) ◽  
pp. 211-218 ◽  
Author(s):  
Renáta Toušová ◽  
Jaromír Ducháček ◽  
Luděk Stádník ◽  
Martin Ptáček ◽  
Sylvana Pokorná
Keyword(s):  
Protein Content ◽  
Milk Production ◽  
Air Temperature ◽  
Somatic Cells ◽  
Climatic Conditions ◽  
Holstein Cows ◽  
Air Humidity ◽  
Relative Air Humidity ◽  
Daily Milk Production ◽  
Daily Milk

The aim of this study was to evaluate influence of climatic conditions represented by daily air temperature and relative air humidity on indicators of Holstein cows’ milk quality and production. The first dataset represented individual milk production in day of milk performance recording (milk kg, fat %, protein %, and somatic cells count thous.*ml−1). The second dataset represented total daily milk characteristics of herd (milk kg, fat %, protein % and somatic cells count thous.*ml−1). A total of 654 Holstein cows were observed and evaluated. Both datasets were evaluated in relation to selected external influences (year, month, average daily air temperature, and average daily relatively air humidity). Statistical analysis was performed using SAS 9.3, and UNIVARIATE, REG and GLM procedure. Three groups of daily air temeperature (< 4.4 °C; 4.4 – 13.2 °C; > 13.2 °C), and daily relative air humidity (< 65.3 %; 65.3 – 80.4 %; > 80.4 %) were conducted for evaluation. Significant (P < 0.05) linear regressions were computed among daily air temperature and all milk production indicators, except of somatic cells count attribute. The highest individual daily milk production (35.94 kg, P < 0.01), and protein content (3.41 %, P < 0.01) were achieved with the highest average daily air temperature. Opposite results were observed for milk yield of herd as well as protein content. Average daily relative air humidity had lower influence on individual and bulk milk samples. The better results were achieved for both datasets (individual and bulk samples) in groups (65.3 – 80.4 %; > 80.4 %) of average daily relative air humidity. Obtained results point out importance of outdoor climatic parameters monitoring and preventive measures of climatic conditions in the stable.

scholarly journals Interaction between Edge-Crack and Aggregate in Silicate-Based Composite

2017 ◽  
Vol 17 (2) ◽  
pp. 59-64
Author(s):  
Lucie Malíková ◽  
Jan Klusák
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Edge Crack ◽  
Matrix Material ◽  
Interfacial Transition Zone ◽  
Bending Test ◽  
Geometrical Parameters ◽  
The Finite Element Method ◽  
Three Point Bending

Abstract The paper deals with investigation of the interaction between an edge-crack and an aggregate in a silicate-based composite, because adding of aggregates into basic matrix material can improve the fracture mechanical properties of the material significantly. In this work, the three-point-bending test is modelled by means of the finite element method and the dependences of fracture parameters on various material and geometrical parameters of the aggregate and the interfacial transition zone are studied. The results are discussed thoroughly.

A Study on Mechanical Behavior of Dental Hard Tissues and Dental Restorative Materials by Three-Point Bending Test

2014 ◽  
Author(s):  
K. J. Chun ◽  
C. Y. Kim ◽  
J. Y. Lee
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Gold Alloy ◽  
Bending Test ◽  
Dental Resin ◽  
Three Point Bending ◽  
Bending Force ◽  
Dental Restorative Materials ◽  
Restorative Materials ◽  
Dental Restorative

Dental restorative materials including amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy are used to reconstruct damaged teeth, as well as to recover their function. In this study, the mechanical properties of various dental restorative materials were determined using test specimens of identical shape and dimension under the same three-point bending test condition, and the test results were compared to enamel and dentin. The maximum bending force of enamel and dentin was 6.9 ± 2.1 N and 39.7 ± 8.3 N, and the maximum bending deflection was 0.12 ± 0.02 mm and 0.25 ± 0.03 mm, respectively. The maximum bending force of amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy were 1.9 ± 0.4 N, 2.7 ± 0.6 N, 66.9 ± 4.1 N, 2.7 ± 0.3 N, 19.0 ± 2.0 N, and 121.3 ± 6.8 N, respectively, and the maximum bending deflection was 0.20 ± 0.08 mm, 0.28 ± 0.07 mm, 2.53 ± 0.12 mm, 0.37 ± 0.05 mm, 0.39 ± 0.05 m, and 2.80 ± 0.08 mm, respectively. The dental restorative materials that possessed greater maximum bending force than that of enamel were gold alloy, zirconia, and titanium alloy. Gold alloy and titanium alloy had greater maximum bending force than dentin. The dental restorative materials that possessed greater maximum bending deflection than that of enamel were all of the dental restorative materials, and the dental restorative materials that possessed greater maximum bending deflection than that of dentin were all of the dental restorative materials except amalgam. The appropriate dental restorative materials for enamel are gold alloy and zirconia and for dentin is gold alloy concerning the maximum bending force and the maximum bending deflection. These results are expected to aid dentists in their choice of better clinical treatment and to contribute to the development of dental restorative materials that possess properties that are most similar to the mechanical properties of dental hard tissue.

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