Hardwood species bonding properties after cyclic changes of environmental conditions

2020 ◽  
Vol 52 (2) ◽  
pp. 237-242
Author(s):  
Tomás Pipiska ◽  
Pavel Král
Keyword(s):  
Environmental Conditions ◽  
Hardwood Species ◽  
Bonding Properties ◽  
Cyclic Changes

scholarly journals Effect of Variable Conditions of Exposure on the Physical and Mechanical Properties of Blockboards

2022 ◽  
Vol 12 (2) ◽  
pp. 609
Author(s):  
Octavia Zeleniuc ◽  
Camelia Coșereanu
Keyword(s):  
Mechanical Properties ◽  
Interior Design ◽  
Environmental Conditions ◽  
Physical And Mechanical Properties ◽  
Solid Wood ◽  
Raw Material ◽  
Climatic Chamber ◽  
Parameter Variations ◽  
The Face ◽  
Cyclic Changes

The growing demand for wood and the continued increase of the raw material price have resulted in companies using more efficient wood resources in wood-based products such as blockboard. These boards are used in the field of interior design, especially. The aim of this research was to evaluate the effect of variable environmental conditions on the physical and mechanical properties of blockboard (BK). Two types of commercial BK were exposed in variable environmental conditions (kitchen, bathroom and climatic chamber) for three months. The BK structures were composed of veneer (V) and high-density fibreboards (HDF) for the face sheets and glued, solid wood, resinous strips for the core. The temperature and relative humidity of the air (RH) ranged from 18 °C to 25 °C and from 25% to 90%, respectively. In the climatic chamber (CC), the dynamics of the parameter variations were different than in the other two exposure climates, being determined by the programmed cyclic changes in RH. The changes observed on physical and mechanical properties were more extreme for the blockboards tested in the CC than in the kitchen (K) and bathroom (Ba). After 3 months of exposure in the CC, the thickness and weight of the boards increased by 1.8 and 1.1 times, respectively, for veneered BK, and by 4.4 and 0.4 times, for BK with HDF faces, compared to values recorded in the kitchen. The panels exposed in the CC exhibited the highest increase in moisture content (MC): 41% for veneered BK and 82% for BK with HDF faces after three months of exposure, followed by those exposed in the bathroom and kitchen. Increases in MC determined decreases of flexural properties and soundness surfaces, more evident for HDF face structures compared to V ones.

scholarly journals Survey of selected adhesive bonding properties of nine European softwood and hardwood species

2016 ◽  
Vol 74 (6) ◽  
pp. 809-819 ◽  
Author(s):  
Johannes Konnerth ◽  
Marcel Kluge ◽  
Georg Schweizer ◽  
Milica Miljković ◽  
Wolfgang Gindl-Altmutter
Keyword(s):  
Adhesive Bonding ◽  
Hardwood Species ◽  
Bonding Properties

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

The influence of external conditions on sound pressure in the pistonphone at the infrasound frequency range

2020 ◽  
pp. 67-72
Author(s):  
A. V. Konkov ◽  
D. V. Golovin
Keyword(s):  
Environmental Conditions ◽  
Sound Pressure ◽  
Primary Method ◽  
Frequency Range ◽  
External Conditions ◽  
Numerical Estimations

The influence of environmental conditions on a sound pressure reproduced by the primary method in the measuring chambers of the Pistonphone in the frequency range from 1 mHz to 250 Hz is estimated. Numerical estimations of influence of environmental conditions on sound pressure in pistonphone measuring chambers are given and special requirements to system of maintenance of required external conditions are specified.

Disentangling the role of shared ancestry and the environment on leaf stable isotopes

2019 ◽  
Author(s):  
Marko J. Spasojevic ◽  
Sören Weber1
Keyword(s):  
Stable Isotopes ◽  
Environmental Conditions ◽  
Evolutionary History ◽  
Environmental Control ◽  
Phylogenetic Signal ◽  
Individual Species ◽  
Habitat Types ◽  
Δ13c And Δ15n ◽  
Environmental Controls ◽  
Shared Ancestry

Stable carbon (C) and nitrogen (N) isotopes in plants are important indicators of plant water use efficiency and N acquisition strategies. While often regarded as being under environmental control, there is growing evidence that evolutionary history may also shape variation in stable isotope ratios (δ13C and δ15N) among plant species. Here we examined patterns of foliar δ13C and δ15N in alpine tundra for 59 species in 20 plant families. To assess the importance of environmental controls and evolutionary history, we examined if average δ13C and δ15N predictably differed among habitat types, if individual species exhibited intraspecific trait variation (ITV) in δ13C and δ15N, and if there were a significant phylogenetic signal in δ13C and δ15N. We found that variation among habitat types in both δ13C and δ15N mirrored well-known patterns of water and nitrogen limitation. Conversely, we also found that 40% of species exhibited no ITV in δ13C and 35% of species exhibited no ITV in δ15N, suggesting that some species are under stronger evolutionary control. However, we only found a modest signal of phylogenetic conservatism in δ13C and no phylogenetic signal in δ15N suggesting that shared ancestry is a weaker driver of tundra wide variation in stable isotopes. Together, our results suggest that both evolutionary history and local environmental conditions play a role in determining variation in δ13C and δ15N and that considering both factors can help with interpreting isotope patterns in nature and with predicting which species may be able to respond to rapidly changing environmental conditions.

Freshwater Mussel (Batissa violacea) Fishery and its Value in Fiji

2019 ◽  
Vol 39 (1) ◽  
Author(s):  
Jimaima Lako ◽  
Nanise Kuridrani ◽  
Milika Sobey
Keyword(s):  
Value Chain ◽  
Environmental Conditions ◽  
Rural Women ◽  
Freshwater Mussel ◽  
Face To Face

This paper examines the local freshwater mussel, or kai (Batissa violacea), fishery value chain, its values and contribution to the livelihood of people in Viti Levu, Fiji. The assessment was performed through face-to-face interviews, with the use of semi-structured questionnaires administered to 125 actors. A walk through the value-chain was also conducted that confirmed the sites’ environmental conditions. Results revealed that even though the kai fishery is dominated by rural women, men were also employed as kai processors, transporting agents and exporters. This fishery generated at least 58 other employments through the 500 kai harvesters within the five major provinces understudy. These were drivers, boat builders, retailers, processors, exporters, and harvesters. Three sales pathways were identified that determined the revenues and profits: (i) harvesters sell own harvests directly to the consumer at the municipal markets, (ii) harvesters sell through intermediary traders to consumers, and (iii) harvesters sell through processors to supermarkets, hotels or exporters. When revenues and profits were calculated, harvesters earned much less, compared to intermediary traders, processors, and exporters. Major constraints include continuous reduction in catch size of kai, lack of transport, and marketing at the local municipal markets that require improvements.

HISTOMORPHOLOGICAL CHANGES IN THE BRAIN IN RELATION TO OVARIAN CYCLE OF FRESHWATER CRAB, BARYTELPHUSA CUNICULARIS

2017 ◽  
Vol 23 (1) ◽  
Author(s):  
C.A. JAWALE
Keyword(s):  
Staining Intensity ◽  
Neurosecretory Cells ◽  
Ovarian Cycle ◽  
Secretory Product ◽  
Freshwater Crab ◽  
Intensity Index ◽  
Cytoplasmic Material ◽  
Histomorphological Changes ◽  
Cyclic Changes ◽  
The Brain

Ovarian maturation by neurosecretory cells in the brain of freshwater crab, Barytelphusa cunicularis have been examined. The histological scrutiny of the brain of Barytelphusa cunicularis related with three types (A, B and C) of neurosecretory cells, which are classified on the basis of size, shape and tinctorial characters. All these types of cells marked annual cyclic changes of cytoplasmic material in association with ovarian cycle. The activity of these cells has been correlated with the ovarian cycle. They are distinguishable by their size, nature locations, shape, nucleus position, cell measure and the secretory product in the cytoplasm. The result indicates that the neurosecretory A, B and C cells of the brain seen involved in the process of mating ovulation. The neurosecretory materials staining intensity index of these cells is described.

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