scholarly journals Reinforcing the Structural Stability of Old Nationally Important Trees with FRP Wraps

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Zheong Jun Yi ◽  
Junsuk Kang
Keyword(s):  
Structural Stability ◽  
Wind Loads ◽  
Main Trunk ◽  
Visual Aesthetics ◽  
National Importance ◽  
Tall Tree ◽  
Experimental Approaches ◽  
Complex Structural ◽  
Old Trees ◽  
Structural Behaviors

This study evaluated the structural effects of applying fiber-reinforced polymer (FRP) wraps around their trunks to support old trees of national importance. High wind loads such as windstorms or hurricanes represent a major threat to tall trees, and researchers have assessed the structural behaviors of trees under wind loads using both analytical and experimental approaches. As yet, however, there is no widely accepted method to safely reinforce the structural stability of nationally and historically important tall trees subject to severe wind loads. Traditional reinforcing methodologies can actually damage supported areas as the supports are relatively stiff compared to the main trunk, introducing stressful interactions. FRP materials have high tensile strength, durability, and flexibility; hence, wrapping them around the surface of the tree trunk could enhance the overall stability of a tall tree subjected to high winds without sacrificing the tree’s visual aesthetics or damaging the bark. This study applied nonlinear finite element (FE) analyses to evaluate the complex structural behaviors of the wood and FRP wraps, both of which are anisotropic materials. The results revealed that FRP wraps offer a highly effective way to enhance the structural stability of tall trees with minimal cost.

A graph theoretical approach for assessing bio-macromolecular complex structural stability

2009 ◽  
Vol 15 (11) ◽  
pp. 1349-1370 ◽  
Author(s):  
Carlos Adriel Del Carpio ◽  
Mihai Iulian Florea ◽  
Ai Suzuki ◽  
Hideyuki Tsuboi ◽  
Nozomu Hatakeyama ◽  
...  
Keyword(s):  
Structural Stability ◽  
Theoretical Approach ◽  
Macromolecular Complex ◽  
Graph Theoretical Approach ◽  
Complex Structural

scholarly journals Development of a Reinforced Concrete Sheet Pile Wall Element

2020 ◽  
Author(s):  
Kristóf Lődör ◽  
János Szendefy ◽  
Olivér Kovács ◽  
Zsombor Illés
Keyword(s):  
Reinforced Concrete ◽  
Design Concept ◽  
Sheet Pile ◽  
Major Player ◽  
Wall Element ◽  
Geotechnical Design ◽  
Complex Structural ◽  
Structural Behaviors ◽  
Concrete Elements ◽  
Sheet Pile Wall

In the forthcoming years intensive renovation and reconstruction works can be expected on the banks’ freshwaters of Hungary. For the rehabilitation of the shores of Lake Velence works are starting in 2020. To support these investments there has been a demand for prefabricated reinforced concrete sheet pile walls. Realizing the opportunity, a major player in the market of pre-fabricated reinforced concrete elements for water way construction, CSOMIÉP Ltd. decided to develop a reinforced concrete sheet pile wall. In this study the development and complex structural and geotechnical design concept are shown through the major structural behaviors and useable geometries.

scholarly journals VEGETATIVE RESCUE AND CUTTINGS PROPAGATION OF Araucaria angustifolia (Bertol.) Kuntze

2015 ◽  
Vol 39 (1) ◽  
pp. 93-104 ◽  
Author(s):  
Ivar Wendling ◽  
Gilvano Ebling Brondani
Keyword(s):  
Butyric Acid ◽  
Coniferous Tree ◽  
Araucaria Angustifolia ◽  
Southern Brazil ◽  
Wood Production ◽  
Main Trunk ◽  
Old Trees ◽  
Upper Third ◽  
Environmental Importance

Brazilian pine or araucaria (Araucaria angustifolia) is a coniferous tree with great economic, social and environmental importance in southern Brazil, being exploited for both wood production and for its edible pine nuts. However, no efficient cloning techniques are available and, therefore, the purpose of this study was to evaluate the effectiveness of vegetative rescue methods for cuttings propagation of the species. Shoots/cuttings were generated in two ways: 26 years old trees underwent coppicing and 20 years old trees had the primary branches on the upper third of crown pruned at 2, 20 and 50 cm from the main trunk. Orthotropic shoots were rooted after application of indole-3-butyric acid (IBA) at 0, 2, 4 and 6 g.L-1. Coppicing produced 47 cuttings per plant with 90% orthotropic shoots, while pruning resulted in 182 cuttings per plant with 44% orthotropic shoots. Rooting success indexes were low with no influence of IBA, although they are slightly superior to the ones available in the literature for the species, ranging from 12 to 30% for the coppice shoots and from 0 to 28% for the branches shoots. We conclude that both vegetative rescue techniques are viable and have potentially important applications. Coppicing is recommended for the propagation aiming the production of wood, while shoots derived from the side branches of the crown are more appropriate for seeds orchards formation.

scholarly journals Structural Behaviors of Reinforced Concrete Piers Rehabilitated with FRP Wraps

2017 ◽  
Vol 2017 ◽  
pp. 1-14
Author(s):  
Junsuk Kang
Keyword(s):  
Reinforced Concrete ◽  
Fiber Reinforced Polymer ◽  
Design Parameters ◽  
Masonry Structures ◽  
Finite Element Analyses ◽  
Maintenance Costs ◽  
Existing Structures ◽  
Reinforced Polymer ◽  
Complex Structural ◽  
Structural Behaviors

The use of fiber-reinforced polymer (FRP) wraps to retrofit and strengthen existing structures such as reinforced concrete piers is becoming popular due to the higher tensile strength, durability, and flexibility gained and the method’s ease of handling and low installation and maintenance costs. As yet, however, few guidelines have been developed for determining the optimum thicknesses of the FRP wraps applied to external surfaces of concrete or masonry structures. In this study, nonlinear pushover finite element analyses were utilized to analyze the complex structural behaviors of FRP-wrapped reinforced rectangular piers. Design parameters such as pier section sizes, pier heights, pier cap lengths, compressive strengths of concrete, and the thicknesses of the FRP wraps used were thoroughly tested under incremental lateral and vertical loads. The results provide useful guidelines for analyzing and designing appropriate FRP wraps for existing concrete piers.

A propos d'Osmoderma eremita (Scopoli, 1763) en Suisse

2012 ◽  
Vol 163 (7) ◽  
pp. 271-276 ◽  
Author(s):  
Mickaël Blanc
Keyword(s):  
Land Use ◽  
Cultural Heritage ◽  
Quercus Robur ◽  
Osmoderma Eremita ◽  
National Importance ◽  
Hollow Trees ◽  
The Creation ◽  
Old Trees

About Osmoderma eremita (Scopoli, 1763) in Switzerland The finding of fragments of Osmoderma eremita (Coleoptera, Scarabaeidae, Cetoniinae) in September 2009, at the base of an oak (Quercus robur) in Geneva's countryside, suggests that this beetle of national importance still occurs in the canton of Geneva. The survival of this species relies on the availability of old hollow trees. These have largely disappeared with the intensification of land use and the changes in sylvopastoral practices. The creation and tending of hedge networks hosting large old trees would allow not only to preserve an emblematic species, but also the witnesses of ancient practices and cultural heritage.

An electron microscopic study of the intra-myocardial lesions in cases of acute myocardial infarction

1978 ◽  
Vol 36 (2) ◽  
pp. 484-485
Author(s):  
Masahiro Ono ◽  
Kaoru Aihara ◽  
Gompachi Yajima
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Coronary Vessels ◽  
Vascular Wall ◽  
Vascular Changes ◽  
Electron Microscopic ◽  
Main Trunk ◽  
Mechanical Destruction ◽  
Transmission Electron ◽  
Myocardial Lesions

The pathogenesis of the arteriosclerosis in the acute myocardial infarction is the matter of the extensive survey with the transmission electron microscopy in experimental and clinical materials. In the previous communication,the authors have clarified that the two types of the coronary vascular changes could exist. The first category is the case in which we had failed to observe no occlusive changes of the coronary vessels which eventually form the myocardial infarction. The next category is the case in which occlusive -thrombotic changes are observed in which the myocardial infarction will be taken placed as the final event. The authors incline to designate the former category as the non-occlusive-non thrombotic lesions. The most important findings in both cases are the “mechanical destruction of the vascular wall and imbibition of the serous component” which are most frequently observed at the proximal portion of the coronary main trunk.

Time-resolved high-resolution electron microscopy of structural stability in mgo clusters

1996 ◽  
Vol 54 ◽  
pp. 672-673
Author(s):  
T. Kizuka ◽  
N. Tanaka
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Magnesium Oxide ◽  
Structural Stability ◽  
High Resolution Electron Microscopy ◽  
Video Tape ◽  
Solid State Physics ◽  
Time Resolved ◽  
Resolution Electron ◽  
Structural And Functional Properties

Structure and stability of atomic clusters have been studied by time-resolved high-resolution electron microscopy (TRHREM). Typical examples are observations of structural fluctuation in gold (Au) clusters supported on silicon oxide films, graphtized carbon films and magnesium oxide (MgO) films. All the observations have been performed on the clusters consisted of single metal element. Structural stability of ceramics clusters, such as metal-oxide, metal-nitride and metal-carbide clusters, has not been observed by TRHREM although the clusters show anomalous structural and functional properties concerning to solid state physics and materials science.In the present study, the behavior of ceramic, magnesium oxide (MgO) clusters is for the first time observed by TRHREM at 1/60 s time resolution and at atomic resolution down to 0.2 nm.MgO and gold were subsequently deposited on sodium chloride (001) substrates. The specimens, single crystalline MgO films on which Au particles were dispersed were separated in distilled water and observed by using a 200-kV high-resolution electron microscope (JEOL, JEM2010) equipped with a high sensitive TV camera and a video tape recorder system.

Bipolar radiofrequency induced thermotherapy and 1064 nm Nd:Yag laser in endovenous occlusion of insufficient veins: short term follow up results

VASA ◽  
2011 ◽  
Vol 40 (3) ◽  
pp. 235-240 ◽  
Author(s):  
Krnic ◽  
Sucic
Keyword(s):  
Side Effects ◽  
Success Rate ◽  
Nd:Yag Laser ◽  
Main Stem ◽  
Short Term ◽  
Main Trunk ◽  
Bipolar Radiofrequency ◽  
Saphenous Veins ◽  
Skin Redness ◽  
Complete Failure

Background: The aim of this study is to report our results in main stem vein closure using the bipolar radiofrequency induced thermotherapy (RFITT) system and the 1064nm Nd:Yag laser. Patients and methods: 44 incompetent main stem veins (37 great saphenous veins, one lesser saphenous vein, and 6 anterior accessory saphenous veins) in 29 patients were treated using RFITT. 53 incompetent main stem veins (45 great saphenous veins, 4 lesser saphenous veins, and 4 anterior accessory saphenous veins) in 43 patients were treated endovenously with 1064 nm Nd:Yag laser. All patients underwent postoperative duplex scanning within a month after procedure, as well as a short interview regarding postoperative discomfort. Results: In main stem veins treated with RFITT, the success rate within the first month was 86,4 % (38 out of 44 veins). Complete failure rate was 13,6 % (6 out of 44 veins). In 53 main stem veins treated by 1064 nm Nd:Yag laser, the success rate was 100 %, consisting of 98,1 % complete success (52/53 veins), and 1,9 % partial success (1/53 veins). None of the patients treated with RFITT experienced postoperative adverse effects, whereas 13/43 (30,2 %) patients treated with laser had to use oral analgesics after the treatment, and 21/43 (48,8 %) patients reported transient skin changes, such as bruising or skin redness. Conclusions: RFITT system was fairly efficient in the short term for closure of main trunk veins, whereas longer term results are still scarce. Postoperative side effects of RFITT were minimal. 1064nm Nd:Yag laser, according to short term results, proved to be very effective for main stem vein closure. Postoperative side effects related to 1064 nm Nd:Yag endovenous laser treatment proved to be minor, transient, and acceptable.

Learned Placebo Effects in the Immune System

2014 ◽  
Vol 222 (3) ◽  
pp. 148-153 ◽  
Author(s):  
Sabine Vits ◽  
Manfred Schedlowski
Keyword(s):  
Nervous System ◽  
Immune System ◽  
Associative Learning ◽  
Placebo Response ◽  
Immunosuppressive Drug ◽  
Immune Functions ◽  
Placebo Effects ◽  
New Therapeutic Approaches ◽  
Biological Variables ◽  
Experimental Approaches

Associative learning processes are one of the major neuropsychological mechanisms steering the placebo response in different physiological systems and end organ functions. Learned placebo effects on immune functions are based on the bidirectional communication between the central nervous system (CNS) and the peripheral immune system. Based on this “hardware,” experimental evidence in animals and humans showed that humoral and cellular immune functions can be affected by behavioral conditioning processes. We will first highlight and summarize data documenting the variety of experimental approaches conditioning protocols employed, affecting different immunological functions by associative learning. Taking a well-established paradigm employing a conditioned taste aversion model in rats with the immunosuppressive drug cyclosporine A (CsA) as an unconditioned stimulus (US) as an example, we will then summarize the efferent and afferent communication pathways as well as central processes activated during a learned immunosuppression. In addition, the potential clinical relevance of learned placebo effects on the outcome of immune-related diseases has been demonstrated in a number of different clinical conditions in rodents. More importantly, the learned immunosuppression is not restricted to experimental animals but can be also induced in humans. These data so far show that (i) behavioral conditioned immunosuppression is not limited to a single event but can be reproduced over time, (ii) immunosuppression cannot be induced by mere expectation, (iii) psychological and biological variables can be identified as predictors for this learned immunosuppression. Together with experimental approaches employing a placebo-controlled dose reduction these data provide a basis for new therapeutic approaches to the treatment of diseases where a suppression of immune functions is required via modulation of nervous system-immune system communication by learned placebo effects.

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