Protective Systems Ensuring Durability of Wooden Structures

2021 ◽  
Vol 898 ◽  
pp. 101-106
Author(s):  
Petr Kuklík ◽  
Petr Svora ◽  
Anna Gregorová
Keyword(s):  
Surface Modification ◽  
Weight Ratio ◽  
Good Strength ◽  
Biological Attack ◽  
External Conditions ◽  
Proper Design ◽  
Evaluation And Monitoring ◽  
Wooden Structures ◽  
Protective Systems

Wood is a versatile material able to be used in a wide variety of situations and applications. Wood has also very good strength to weight ratio. Problem is degradation of wood due to bad external conditions. The protection of wood takes many forms including proper design detailing. The majority are directed towards the prevention of moisture access and weathering. However, there are also some design details that can also assist in reducing the risk of biological attack. Our work provides a background on a number of important subjects related to good performance of wooden structures. This paper deals with durability of wood, design for durability of wooden structures, surface modification of wood and also evaluation and monitoring of wooden structures.

scholarly journals Topographical and Biomechanical Guidance of Electrospun Fibers for Biomedical Applications

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2896
Author(s):  
Sara Ferraris ◽  
Silvia Spriano ◽  
Alessandro Calogero Scalia ◽  
Andrea Cochis ◽  
Lia Rimondini ◽  
...  
Keyword(s):  
Surface Modification ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Electrospun Fibers ◽  
Natural Polymers ◽  
Polymeric Fibers ◽  
Biological Phenomena ◽  
Proper Design ◽  
Synthetic And Natural Polymers ◽  
Selection Of

Electrospinning is gaining increasing interest in the biomedical field as an eco-friendly and economic technique for production of random and oriented polymeric fibers. The aim of this review was to give an overview of electrospinning potentialities in the production of fibers for biomedical applications with a focus on the possibility to combine biomechanical and topographical stimuli. In fact, selection of the polymer and the eventual surface modification of the fibers allow selection of the proper chemical/biological signal to be administered to the cells. Moreover, a proper design of fiber orientation, dimension, and topography can give the opportunity to drive cell growth also from a spatial standpoint. At this purpose, the review contains a first introduction on potentialities of electrospinning for the obtainment of random and oriented fibers both with synthetic and natural polymers. The biological phenomena which can be guided and promoted by fibers composition and topography are in depth investigated and discussed in the second section of the paper. Finally, the recent strategies developed in the scientific community for the realization of electrospun fibers and for their surface modification for biomedical application are presented and discussed in the last section.

Surface Modification of High Density Ceramic Powder for Increasing Suspension Capacity in Three-Dimensional Printing Application

2018 ◽  
Vol 936 ◽  
pp. 159-163 ◽  
Author(s):  
Huang Jan Hsu ◽  
Shyh Yuan Lee ◽  
Shinn Liang Chang ◽  
Cho Pei Jiang
Keyword(s):  
Surface Modification ◽  
Ball Milling ◽  
Ceramic Powder ◽  
Three Dimensional ◽  
Treatment Protocol ◽  
Weight Ratio ◽  
Average Diameter ◽  
Zirconia Powder ◽  
Three Dimensional Printing ◽  
Promising Tool

Three-dimensional slurry printing is a promising tool for making ceramic object but it limits in high dense ceramic powder because of poor suspension capacity. This study uses zirconia powder with an average diameter of 2 μm because its density is 5.67 g/cm3. A treatment protocol is proposed to improve the suspension capacity of zirconia powder including the ball milling, surface modification and resin blending. Experimental results show that adding 1% of isostearyl titanate, a coupling agent, for surface modification can enhance the lipophilicity of zirconia powder. Mixing surface modification powder in resin with a weight ratio of 7:3 and carrying on ball milling with 100 RPM for 6 hours can obtain the diameter of powder less than 400 nm. As a result, the zirconia slurry can obtain good suspension capacity which is over 48 hours.

Enhanced selectivity and capacity of clinoptilolite for Cd2+ removal from aqueous solutions by incorporation of magnetite nanoparticles and surface modification with cysteine

2016 ◽  
Vol 73 (9) ◽  
pp. 2284-2293 ◽  
Author(s):  
Masumeh Sharifi ◽  
Majid Baghdadi
Keyword(s):  
Surface Modification ◽  
Magnetite Nanoparticles ◽  
Weight Ratio ◽  
Correlation Coefficients ◽  
Effective Parameters ◽  
Equilibrium Data ◽  
Infrared Spectrometer ◽  
Modified Clinoptilolite ◽  
Enhanced Selectivity ◽  
Selectivity And Capacity

In this study, magnetic zeolite (MZ) nanocomposite modified with cysteine was developed in order to enhance selectivity and capacity of clinoptilolite for cadmium ion. The prepared MZ nanocomposite is containing clinoptilolite and magnetite nanoparticles with weight ratio of 3:1. The synthesized nanocomposite was characterized by transmission electron microscopy, X-ray diffraction and vibrating sample magnetometer. Surface modification was confirmed by Fourier transform infrared spectrometer. Experiments were carried out to find the optimum conditions for modification of clinoptilolite and to investigate the effective parameters (pH, adsorbent dosage, contact time, and temperature) on the adsorption of Cd2+ ion by modified clinoptilolite. The results showed enhanced selectivity of modified MZ in the presence of other naturally occurring cations (Na+, K+, Ca2+ and Mg2+) and ammonium. Kinetic and equilibrium data were well fitted by a pseudo second-order and Langmuir model, respectively, with high correlation coefficients. The maximum adsorption capacities of the modified and non-modified clinoptilolite were found to be 20.0 mg/g and 5.2 mg/g, respectively. Thermodynamic parameters revealed that the adsorption process is spontaneous and endothermic under studied conditions.

scholarly journals Synthesis and Surface Modification of Deagglomerated Superparamagnetic Nanoparticles

1996 ◽  
Vol 432 ◽  
Author(s):  
Christoph Lesniak ◽  
Thomas Schiestel ◽  
Riüdiger Nass ◽  
Helmut Schmidt
Keyword(s):  
Surface Modification ◽  
Iron Oxide ◽  
Particle Surface ◽  
Weight Ratio ◽  
Superparamagnetic Iron Oxide ◽  
Superparamagnetic Nanoparticles ◽  
Disintegration Time ◽  
Aqueous Suspensions ◽  
Aqueous Salt Solutions ◽  
Core Particles

AbstractA method for the preparation of aminosilane coated, chemically stable, agglomerate-free superparamagnetic iron oxide nanoparticles (ferrites, e.g. Fe3O4 and γ-Fe2O3) has been developed. These nanocomposite particles posess core-shell structure. The well crystallized core particles are prepared by precipitation from aqueous salt solutions (primary particle size 10 nm). The surface modification of the weakly agglomerated core particles with aminosilane (e.g. γ-aminopropyl- triethoxysilane) leads to deagglomerated particles, covered by a thin polymerized aminosilane shell. A strong dependency of the particle/agglomerate size on the silane/iron oxideratio as well as on the disintegration time was found. A ratio of aminosilane to iron oxide of 0.8 (weight ratio) and a disintegration time of 72h result in overall particle sizes in the range of 10–15 nm. After surface modification, aminogroups are present on the particle surface (IEP of 9.5). The particles show superparamagnetic behaviour (saturation magnetization 68 EMU/g) and aqueous suspensions are stable against agglomeration. A desorption of the coating in aqueous suspensions (pH 3 to 11) is not observed.

scholarly journals COMPREHENSIVE APPROACH TO ENSURE DURABILTY OF EXTERNAL WOODEN STRUCTURES

Wood Research ◽  
2021 ◽  
Vol 66 (6) ◽  
pp. 900-911
Author(s):  
PETR KUKLÍK ◽  
ZDENĚK PROŠEK ◽  
ANNA GREGOROVÁ
Keyword(s):  
Surface Modification ◽  
Electron Microscope ◽  
Reference Material ◽  
Pinus Sylvestris ◽  
Titanium Oxide ◽  
Water Solution ◽  
Comprehensive Approach ◽  
Uv Absorbers ◽  
Wooden Surface ◽  
Wooden Structures

The article deals with durability of wood, durability of wooden structures and surface modification of wood. We are trying to eliminate the factors causing degradation of wood with the use of photocatalytic materials. Those materials are efficient UV absorbers and they are able to destroy biological aggressors also. The planar particles of titanium oxide TiO2 were chosen for the purpose of our research and applied on a wooden surface. In our case, we used a water solution of TiO2. The main goal of our work was to study the interaction between planar particles of TiO2 and wood matter. The samples of pine wood (Pinus sylvestris) were monitored for 255 days and subsequently evaluated using an electron microscope. The use of TiO2 was compared with reference material and a reference commercial coating.

scholarly journals Environmental Degradation of Plastic Composites with Natural Fillers—A Review

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 166 ◽  
Author(s):  
Mihai Brebu
Keyword(s):  
Recent Literature ◽  
Weight Ratio ◽  
Low Density ◽  
Mechanical Forces ◽  
High Tensile Strength ◽  
Negative Effects ◽  
Inert Matrix ◽  
Plastic Composites ◽  
Biological Attack ◽  
Natural Fillers

Polymer composites are widely used modern-day materials, specially designed to combine good mechanical properties and low density, resulting in a high tensile strength-to-weight ratio. However, materials for outdoor use suffer from the negative effects of environmental factors, loosing properties in various degrees. In particular, natural fillers (particulates or fibers) or components induce biodegradability in the otherwise bio inert matrix of usual commodity plastics. Here we present some aspects found in recent literature related to the effect of aggressive factors such as temperature, mechanical forces, solar radiation, humidity, and biological attack on the properties of plastic composites containing natural fillers.

scholarly journals Flexural Behavior of High Strength Self-Compacted Concrete Slabs Containing Treated and Untreated Geogrid Reinforcement

Fibers ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 23 ◽  
Author(s):  
Abd El-Rahman Fares ◽  
Hassan Hassan ◽  
Mohammed Arab
Keyword(s):  
Surface Modification ◽  
Weight Ratio ◽  
High Strength ◽  
Flexural Behavior ◽  
Cement Matrix ◽  
Concrete Slabs ◽  
Loading Capacity ◽  
Chemical Surface ◽  
Flexural Loading ◽  
Modification Method

Geogrid is as one of the component materials classified under the geosynthetics used for soil stabilizing and reinforcement. Due to its higher strength-to-weight ratio, ease of handling, and comparatively low costs, geogrid has been gradually explored for possible use in concrete reinforcement. This research aims to assess the feasibility of using geogrids as a possible reinforcement for high-strength self-compacted concrete slabs to provide additional tensile strength and ductility. To enhance the bond between geogrid layers and the cement matrix, two types of geogrid surface modification methods are introduced. Gluing sand to the geogrid surface as a physical surface modification method and immersion in polycarboxylate as a chemical surface modification method are investigated. The effect of geogrid type (uniaxial, biaxial and triaxial) and the number of layers is also introduced. The test results show that the chemical treatment increased the ultimate flexural loading capacity of the tested slab by about 8.5% for one geogrid layer and 13% for two geogrid layers compared to untreated specimens. This work was extended to add two geogrid layers in addition to the slab’s steel reinforcement. The results show that adding geogrid decreased the ultimate flexural loading capacity but significantly increased the slab ductility.

Plasma Surface Modification of Poly(Lactic-co-Ricinoleic Acid)Urethane: Chemical and Biological Characterizations

2018 ◽  
Vol 382 ◽  
pp. 31-37
Author(s):  
Catherine C. Sumaray ◽  
Emil T. Ngan ◽  
Larry Q. Reyes
Keyword(s):  
Surface Modification ◽  
Lactic Acid ◽  
Ricinoleic Acid ◽  
Weight Ratio ◽  
Hexamethylene Diisocyanate ◽  
Chain Extension ◽  
Normal Fibroblast ◽  
Plasma Surface Modification ◽  
Plasma Surface ◽  
Molecular Weights

Poly (ester urethane) s (PEUs) based on L-lactic acid (LA) and ricinoleic acid (RA), 1,6-hexamethylene diisocyanate (HMDI) were synthesized via polycondensation-chain extension reaction. Melt polycondensation reaction was carried out to produce the prepolymer poly (L-lactic acid-co-ricinoleic acid), with number average molecular weights (Mw) ranging from 3,000 to 10,000 g/mol. The weight ratio between LA with RA were 100:0, 95:5, 90:10, 80:20. The PEUs PEU100:0, PEU95:05, PEU 90:10 and PEU 80:20 were observed to be soft solids. Molecular weights increased after chain extension/coupling reaction with the diisocyanate, producing polymers with Mwranging from 60,000 to 115,000 g/mol. The production of poly (L-lactic acid-co-ricinoleic acid urethane) was verified by infrared (FTIR) and proton-nuclear magnetic (H1-NMR) spectroscopy. The poly (L-lactic acid) and the urethane groups are believed to form hard segment while the poly (ricinoleic acid) segment is the soft segment group. Moreover, oxygen plasma surface modification was also employed to alter the surface properties of the PEU samples Based on scanning electron microscopy (SEM), the surface roughens and hydroxyapatite mineralization were improved after the plasma treatment. The PEU materials were also found to be biocompatible with L929 mouse normal fibroblast cells.

Precipitation in Al-Li-Zr alloys

1992 ◽  
Vol 50 (1) ◽  
pp. 186-187
Author(s):  
D.M. Vanderwalker
Keyword(s):  
Fracture Toughness ◽  
Precipitation Hardening ◽  
Weight Ratio ◽  
High Strength ◽  
Transmission Electron ◽  
Water Quench ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
Lithium Alloys ◽  
Zr Alloys

Aluminum-lithium alloys have a low density and high strength to weight ratio. They are being developed for the aerospace industry.The high strength of Al-Li can be attributed to precipitation hardening. Unfortunately when aged, Al-Li aquires a low ductility and fracture toughness. The precipitate in Al-Li is part of a sequence SSSS → Al3Li → AlLi A description of the phases may be found in reference 1 . This paper is primarily concerned with the Al3Li phase. The addition of Zr to Al-Li is being explored to find the optimum in properties. Zirconium improves fracture toughness and inhibits recrystallization. This study is a comparision between two Al-Li-Zr alloys differing in Zr concentration.Al-2.99Li-0.17Zr(alloy A) and Al-2.99Li-0.67Zr (alloy B) were solutionized for one hour at 500oc followed by a water quench. The specimens were then aged at 150°C for 16 or 40 hours. The foils were punched into 3mm discs. The specimens were electropolished with a 1/3 nitric acid 2/3 methanol solution. The transmission electron microscopy was conducted on the JEM 200CX microscope.

Precipitate coarsening during hot-compression testing of NiAl + 2 at.% Nb

1986 ◽  
Vol 44 ◽  
pp. 598-599
Author(s):  
W. M. Sherman ◽  
K. M. Vedula
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Weight Ratio ◽  
Constant Strain Rate ◽  
Hot Compression ◽  
Compression Testing ◽  
Second Phase ◽  
Precipitate Coarsening ◽  
High Temperature Mechanical Properties ◽  
Ordered Intermetallic

The strength to weight ratio and oxidation resistance of NiAl make this ordered intermetallic, with some modifications, an attractive candidate to compete with many superalloys for high temperature applications. Recent studies have shown that the inherent brittleness of many polycrystalline intermetallics can be overcome by micro and macroalloying. It has also been found that the high temperature mechanical properties of NiAl can be enhanced through the addition of Nb by powder metallurgical techniques forming a dispersed second phase through interdiffusion in a polycrystalline matrix. A drop in the flow stress is observed however in a NiAl-2 at.% Nb alloy after 0.2 % strain during constant strain rate hot compression testing at 1025°C. The object of this investigation was to identify the second phase and to determine the cause of the flow stress drop.

Sign in / Sign up

Export Citation Format

Share Document