scholarly journals Hybrid Approach for Wood Modification: Characterization and Evaluation of Weathering Resistance of Coatings on Acetylated Wood

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 658
Author(s):  
Anna Sandak ◽  
Edit Földvári-Nagy ◽  
Faksawat Poohphajai ◽  
Rene Herrera Diaz ◽  
Oihana Gordobil ◽  
...  
Keyword(s):  
Service Life ◽  
Hybrid Approach ◽  
Wood Properties ◽  
Wood Products ◽  
Superior Performance ◽  
Surface Erosion ◽  
Coating Film ◽  
Chemical Treatments ◽  
Cellular Wall ◽  
Bulk Substrate

Wood, as a biological material, is sensitive to environmental conditions and microorganisms; therefore, wood products require protective measures to extend their service life in outdoor applications. Several modification processes are available for the improvement of wood properties, including commercially available solutions. Among the chemical treatments, acetylation by acetic anhydride is one of the most effective methods to induce chemical changes in the constitutive polymers at the cellular wall level. Acetylation reduces wood shrinkage-swelling, increases its durability against biotic agents, improves UV resistance and reduces surface erosion. However, even if the expected service life for external cladding of acetylated wood is estimated to be 60 years, the aesthetics change rapidly during the first years of exposure. Hybrid, or fusion, modification includes processes where the positive effect of a single treatment can be multiplied by merging with additional follow-up modifications. This report presents results of the performance tests of wood samples that, besides the modification by means of acetylation, were additionally protected with seven commercially available coatings. Natural weathering was conducted in Northern Italy for 15 months. Samples were characterized with numerous instruments by measuring samples collected from the stand every three months. Superior performance was observed on samples that merged both treatments. It is due to the combined effect of the wood acetylation and surface coating. Limited shrinkage/swelling of the bulk substrate due to chemical treatment substantially reduced stresses of the coating film. Hybrid process, compared to sole acetylation of wood, assured superior visual performance of the wood surface by preserving its original appearance.

scholarly journals Wood Properties Characterisation of Thermo-Hydro Mechanical Treated Plantation and Native Tasmanian Timber Species

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1189
Author(s):  
Michelle Balasso ◽  
Andreja Kutnar ◽  
Eva Prelovšek Niemelä ◽  
Marica Mikuljan ◽  
Gregory Nolan ◽  
...  
Keyword(s):  
Mass Loss ◽  
Wood Properties ◽  
High Water ◽  
Radiata Pine ◽  
Wood Products ◽  
Timber Species ◽  
Final Thickness ◽  
Dimensional Changes ◽  
Commercially Important ◽  
Shining Gum

Thermo-hydro mechanical (THM) treatments and thermo-treatments are used to improve the properties of wood species and enhance their uses without the application of chemicals. This work investigates and compares the effects of THM treatments on three timber species from Tasmania, Australia; plantation fibre-grown shining gum (Eucalyptus nitens H. Deane and Maiden), plantation saw-log radiata pine (Pinus radiata D. Don) and native-grown saw-log timber of the common name Tasmanian oak (which can be any of E. regnans F. Muell, E. obliqua L’Hér and E. delegatensis L’Hér). Thin lamellae were compressed by means of THM treatment from 8 mm to a target final thickness of 5 mm to investigate the suitability for using THM-treated lamellas in engineered wood products. The springback, mass loss, set-recovery after soaking, dimensional changes, mechanical properties, and Brinell hardness were used to evaluate the effects of the treatment on the properties of the species. The results show a marked increase in density for all three species, with the largest increase presented by E. nitens (+53%) and the smallest by Tasmanian oak (+41%). E. nitens displayed improvements both in stiffness and strength, while stiffness decreased in P. radiata samples and strength in Tasmanian oak samples. E. nitens also displayed the largest improvement in hardness (+94%) with respect to untreated samples. P. radiata presented the largest springback whilst having the least mass loss. E. nitens and Tasmanian oak showed similar dimensional changes, whilst P. radiata timber had the largest thickness swelling and set-recovery due to the high water absorption (99%). This study reported the effects of THM treatments in less-known and commercially important timber species, demonstrating that the wood properties of a fibre-grown timber can be improved through the treatments, potentially increasing the utilisation of E. nitens for structural and higher quality timber applications.

Generating High-Quality Air-Coupled Ultrasonic Images for Wooden Material Characterization by Single Image Super-Resolution

2019 ◽  
Vol 34 (03) ◽  
pp. 2054008
Author(s):  
Lujun Lin ◽  
Yiming Fang ◽  
Xiaochen Du ◽  
Zhu Zhou
Keyword(s):  
Image Quality ◽  
Super Resolution ◽  
Visual Assessment ◽  
Wood Products ◽  
Superior Performance ◽  
Single Image ◽  
High Quality ◽  
Practical Applications ◽  
Image Super Resolution ◽  
Single Image Super Resolution

As the practical applications in other fields, high-resolution images are usually expected to provide a more accurate assessment for the air-coupled ultrasonic (ACU) characterization of wooden materials. This paper investigated the feasibility of applying single image super-resolution (SISR) methods to recover high-quality ACU images from the raw observations that were constructed directly by the on-the-shelf ACU scanners. Four state-of-the-art SISR methods were applied to the low-resolution ACU images of wood products. The reconstructed images were evaluated by visual assessment and objective image quality metrics, including peak signal-to-noise-ratio and structural similarity. Both qualitative and quantitative evaluations indicated that the substantial improvement of image quality can be yielded. The results of the experiments demonstrated the superior performance and high reproducibility of the method for generating high-quality ACU images. Sparse coding based super-resolution and super-resolution convolutional neural network (SRCNN) significantly outperformed other algorithms. SRCNN has the potential to act as an effective tool to generate higher resolution ACU images due to its flexibility.

scholarly journals Intelligent security system detects the hidden objects in the smart grid

2020 ◽  
Vol 19 (1) ◽  
pp. 188
Author(s):  
Ammar Wisam Altaher ◽  
Abdullah Hasan Hussein
Keyword(s):  
Image Fusion ◽  
Search Algorithm ◽  
Detection System ◽  
Harmony Search ◽  
Hybrid Approach ◽  
Human Vision ◽  
Superior Performance ◽  
Support Vector ◽  
Accurate Information ◽  
Discrete Wavelet

<p>Monitoring the general public gathered in large numbers is one of the most challenging tasks faced by the law and order enforcement team. There is swiftly demand to that have inbuilt sensors which can detect the concealed weapon, from a standoff distance the system can locate the weapon with very high accuracy. Objects that are obscure and invisible from human vision can be seen vividly from enhanced artificial vision systems. Image Fusion is a computer vision technique that fuses images from multiple sensors to give accurate information. Image fusion using visual and infrared images has been employed for a safe, non-invasive standoff threat detection system. The fused imagery is further processed for specific identification of weapons. The unique approach to discover concealed weapon based on DWT in conjunction with Meta heuristic algorithm Harmony Search Algorithm and SVM classification is presented. It firstly uses the traditional discrete wavelet transform along with the hybrid Hoteling transform to obtain a fused imagery. Then a heuristic search algorithm is applied to search the best optimal harmony to generate the new principal components of the registered input images which is later classified using the K means support vector machines to build better classifiers for concealed weapon detection. Experimental results demonstrate the hybrid approach which shows the superior performance.</p>

scholarly journals Hybrid Approach for Image Defogging Process based on Atmospheric Light Estimation Process

2021 ◽  
Vol 3 (3) ◽  
pp. 184-195
Author(s):  
Akey Sungheetha
Keyword(s):  
Hybrid Approach ◽  
Estimation Algorithm ◽  
Superior Performance ◽  
Statistical Process ◽  
Estimation Process ◽  
Multiple Sensors ◽  
Image Defogging ◽  
Dark Channel ◽  
Web Camera ◽  
Atmospheric Light

Due to unfavorable weather circumstances, images captured from multiple sensors have limited the contrast and visibility. Many applications, such as web camera surveillance in public locations are used to identify object categorization and capture a vehicle's licence plate in order to detect reckless driving. The traditional methods can improve the image quality by incorporating luminance, minimizing distortion, and removing unwanted visual effects from the given images. Dehazing is a vital step in the image defogging process of many real-time applications. This research article focuses on the prediction of transmission maps in the process of image defogging through the combination of dark channel prior (DCP), transmission map with refinement, and atmospheric light estimation process. This framework has succeeded in the prior segmentation process for obtaining a better visualization. This prediction of transmission maps can be improved through the statistical process of obtaining higher accuracy for the proposed model. This improvement can be achieved by incorporating the proposed framework with an atmospheric light estimation algorithm. Finally, the experimental results show that the proposed deep learning model is achieving a superior performance when compared to other traditional algorithms.

scholarly journals Fi-Fo Detector: Figure and Formula Detection Using Deformable Networks

2020 ◽  
Vol 10 (18) ◽  
pp. 6460
Author(s):  
Junaid Younas ◽  
Shoaib Ahmed Siddiqui ◽  
Mohsin Munir ◽  
Muhammad Imran Malik ◽  
Faisal Shafait ◽  
...  
Keyword(s):  
Computer Vision ◽  
Image Representation ◽  
Hybrid Approach ◽  
Representation Learning ◽  
Superior Performance ◽  
Document Images ◽  
Connected Component ◽  
Study Results ◽  
Image Representations ◽  
Ablation Study

We propose a novel hybrid approach that fuses traditional computer vision techniques with deep learning models to detect figures and formulas from document images. The proposed approach first fuses the different computer vision based image representations, i.e., color transform, connected component analysis, and distance transform, termed as Fi-Fo image representation. The Fi-Fo image representation is then fed to deep models for further refined representation-learning for detecting figures and formulas from document images. The proposed approach is evaluated on a publicly available ICDAR-2017 Page Object Detection (POD) dataset and its corrected version. It produces the state-of-the-art results for formula and figure detection in document images with an f1-score of 0.954 and 0.922, respectively. Ablation study results reveal that the Fi-Fo image representation helps in achieving superior performance in comparison to raw image representation. Results also establish that the hybrid approach helps deep models to learn more discriminating and refined features.

Hybrid Approach to Integrated QoS Capable Protocols for Wireless LANs

2010 ◽  
pp. 1-29
Author(s):  
Thomas D. Lagkas
Keyword(s):  
Hybrid Approach ◽  
Superior Performance ◽  
Resource Assignment ◽  
Network Applications ◽  
Access Scheme ◽  
Wireless Environment ◽  
And Performance ◽  
Hybrid Coordination ◽  
Coordination Function

The recent evolution of wireless networking has led the market to increased service demands. Thus, the emerged necessity is to develop specialized mechanisms that provide efficient QoS (Quality of Service) for both traditional and modern network applications in the challenging wireless environment. The respective IEEE proposal comes from the 802.11e workgroup which has developed the Hybrid Coordination Function (HCF). HCF is definitely capable of providing QoS, however, it exhibits significant limitations. This work presents an alternative protocol with improved behavior and performance. The Priority Oriented Hybrid Access (POHA) is a complete channel access mechanism able to provide integrated QoS for all types of traffic and network applications. POHA combines a polling based and a TDMA access scheme, adapts to the dynamic conditions of modern WLANs, improves channel utilization and station feedback, provides medium contention fairness, eliminates collisions, differentiates traffic based on priorities, supports dynamic resource assignment, and instantly negotiates the quality levels of the offered traffic streams trying to support multiple streams with best possible quality. POHA, compared with HCF, exhibits generally superior performance.

scholarly journals Caffeine and TiO2 Nanoparticles Treatment of Spruce and Beech Wood for Increasing Transparent Coating Resistance against UV-Radiation and Mould Attacks

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1141
Author(s):  
Miloš Pánek ◽  
Kristýna Šimůnková ◽  
David Novák ◽  
Ondřej Dvořák ◽  
Ondřej Schönfelder ◽  
...  
Keyword(s):  
Contact Angle ◽  
Service Life ◽  
Tio2 Nanoparticles ◽  
Beech Wood ◽  
Accelerated Weathering ◽  
Coating Film ◽  
Mould Growth ◽  
Spruce Wood ◽  
Transparent Coating ◽  
Positive Effect

The effect of the initial modification of beech and spruce wood using a solution of caffeine and of a commercial product FN-NANO® FN-1 containing a water dispersion of TiO2 nanoparticles for increasing the service life of a transparent oil and acrylate coatings during 6 weeks of artificial accelerated weathering was tested. Changes in colour, gloss, and the contact angle of water were monitored. Degradation of the coating film was also evaluated visually and microscopically. The resistance of the coatings to mould growth was also subsequently tested. Based on the results, it is possible to recommend the initial treatment of spruce and beech wood with a 2% caffeine solution or 15% solution of FN-NANO® dispersion to increase the overall life of a transparent acrylic coating in exterior applications. No positive effect of the applied treatments was observed with the oil coating. In addition, lower concentrations of FN-NANO® did not have a sufficient effect, and the synergistic effect of using FN-NANO® in a mixture with a 1% caffeine solution was also not confirmed.

scholarly journals Fatigue life assessment of TTC streetcar concrete pavements

2021 ◽  
Author(s):  
Bahram Farhang
Keyword(s):  
Life Cycle ◽  
Service Life ◽  
Fatigue Cracks ◽  
Fatigue Loading ◽  
Life Assessment ◽  
Superior Performance ◽  
Experimental Program ◽  
Impact Fatigue ◽  
Construction Methods ◽  
The Impact

The Toronto Transit Commission, TTC traditional embedded track for mechanically jointed rails, is performing satisfactory except for accelerated surface concrete deterioration. By far the most damaging group of deterioration processes in streetcars concrete pavement is due to wheel impact on the joints which will subsequently excite a response on the track. The enhancement of special trackwork, STW service life was the initiative to explore encapsulation technology advances in embedded track materials and construction methods. This aimed to extend the life cycle of the track from current average of 15 years towards target life of 50 years. In the present study, attempts at finding and patterning the localized cracks, especially wheel impact fatigue cracks, are carried out. This issue was investigated during the course of an experimental program demonstrated by simulating the wheel impact loading in concrete under repeated load application. Specially designed specimens were used to represent sheet rubber and urethane encapsulation system proposal against the current assembly. This research reviews the pros and cons of various factors influencing the life cycle of the current assembly and examining and assessing between alternative track construction methods and materials at the joints and examining the concrete's performance both during the impact fatigue loading resulting in inclined cracking and ongoing service life and durability issues under combined environmental and mechanical loadings. Experimental results show that it is possible to achieve the targeted service life of 50 years, based on minimum of 10 time superior performance for either of the proposed encapsulation technologies vs. current construction methods.

scholarly journals Prefabricated Timber Concrete Composite Floors

2016 ◽  
Author(s):  
Thomas Tannert
Keyword(s):  
Precast Concrete ◽  
Wood Products ◽  
Embodied Energy ◽  
Superior Performance ◽  
Concrete Slabs ◽  
Fire Performance ◽  
Adhesively Bonded ◽  
Three Solutions ◽  
Recent Developments ◽  
The Individual

Timber-concrete-composite (TCC) floors are an example of hybrid systems that integrate different materials to achieve superior performance than the individual materials can provide. The structural and non-structural benefits of TCC floors over generic timber floors include increased capacity and stiffness, hallower depth, improved sound protection, and superior fire performance. Rapid erection due to the use of the timber as formwork, more economical gravity systems and foundations due to lighter weight, lower embodied energy, and reduced carbon footprint are advantages when comparing TCC systems to concrete slabs. This paper gives an overview of recent developments including research carried out on three novel solutions: 1) the äóìSwiss-Wood-Concrete-Flooräó�; 2) adhesively bonded TCC; and 3) äóìFT connectorsäó� that are embedded in precast concrete. All three solutions are well suited for modular and off-site construction and show the potential of using wood products beyond current limitations.

Stiffness of Douglas-fir lumber: effects of wood properties and genetics

2011 ◽  
Vol 41 (6) ◽  
pp. 1160-1173 ◽  
Author(s):  
Vikas Vikram ◽  
Marilyn L. Cherry ◽  
David Briggs ◽  
Daniel W. Cress ◽  
Robert Evans ◽  
...  
Keyword(s):  
Stress Wave ◽  
Transverse Vibration ◽  
Genetic Correlations ◽  
Genetic Selection ◽  
Microfibril Angle ◽  
Wood Properties ◽  
Douglas Fir ◽  
Bending Stiffness ◽  
Wood Products ◽  
Strong Positive Correlation

Because stiffness (modulus of elasticity (MOE)) is important for structural wood products, breeders and silviculturists seek to efficiently measure and improve this trait. We studied MOE in a 25-year-old progeny test of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) using field-based tools (ST300 and HM200) to measure stress wave MOE of standing trees and logs. We measured density, static bending MOE, and transverse vibration MOE on 2 × 4s, and density, SilviScan MOE, and SilviScan microfibril angle on small clearwood samples. Bending MOE had moderate to strong phenotypic and genetic correlations with stress wave MOE of trees and logs, transverse vibration MOE of 2 × 4s, and the densities of 2 × 4s and basal wood discs but was weakly correlated with the numbers and sizes of knots. The best lumber grade had the highest bending stiffness and smallest edge knots. Bending stiffness had a strong positive correlation with the density of small clearwood samples and a moderate negative correlation with microfibril angle. Compared with microfibril angle and edge knots, path analyses indicated that density had the strongest direct effect on bending MOE. We recommend that breeders measure and select for stress wave velocity to improve bending stiffness in Douglas-fir. Genetic gains can be increased by including wood density, but genetic selection for fewer or smaller knots will be ineffective.

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