Resistance to Pulsed Electric Current: an Indicator of Stress in Forest Trees

1975 ◽  
Vol 5 (4) ◽  
pp. 557-561 ◽  
Author(s):  
Philip M. Wargo ◽  
H. Richard Skutt
Keyword(s):  
Electric Current ◽  
Gypsy Moth ◽  
Tree Species ◽  
Pulsed Current ◽  
Forest Trees ◽  
Crown Condition ◽  
Oak Trees ◽  
Pulsed Electric Current ◽  
Relationship Of ◽  
The Relationship

Resistance to pulsed electric current was measured in stem tissues of white, chestnut, black, and red oak trees that had been defoliated by the gypsy moth, and their resistance was compared with that of undefoliated trees. Resistance to pulsed current was affected by tree species, diameter, crown class, and crown condition. However, regardless of species, diameter, crown class, or crown condition, defoliated trees had higher resistances than undefoliated trees. The relationship of resistance to pulsed current and tree vigor is discussed.

Effect of Pulsed Current on the Microstructure and Distribution of C and Mn in an Fe-0.5C-1.5Mn Alloy

2010 ◽  
Vol 146-147 ◽  
pp. 1612-1616
Author(s):  
Hai Chuan Wang ◽  
Peng Hong ◽  
Zhi You Liao ◽  
Xin Li ◽  
Jie Lie ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Current ◽  
Pulsed Electric Field ◽  
Pulsed Current ◽  
Banded Structure ◽  
Electric Treatment ◽  
Pulsed Electric Current ◽  
Acicular Structure ◽  
Pulsed Voltage

A pulsed electric current (19 kHz, 0-8 volts) has been applied to a molten Fe-0.5C-1.5Mn alloy to investigate its effect on the microstructure and the distribution of carbon and manganese. It has been shown that the pulsed electric field can improve the microstructure from a coarse banded structure to a compact acicular structure by increasing the pulsed voltage from 4 volts to 8 volts. The pulsed electric treatment also has an effect on the C and Mn distribution with a tendency for C and Mn to migrate to the cathode.

scholarly journals Особенности затухания и усиления терагерцовых плазмонных мод в графене с учетом пространственной дисперсии

2021 ◽  
Vol 55 (10) ◽  
pp. 850
Author(s):  
О.В. Полищук ◽  
Д.В. Фатеев ◽  
В.В. Попов
Keyword(s):  
Charge Carrier ◽  
Phase Velocity ◽  
Fermi Level ◽  
Electric Current ◽  
Dispersion Relations ◽  
Hydrodynamic Description ◽  
Direct Electric Current ◽  
Relationship Of ◽  
The Relationship ◽  
Plasmon Modes

In this paper, we consider the effect of charge carrier drift on plasmon modes (plasmons) in electron Dirac liquid in graphene with a shifted Fermi level. Dispersion relations for plasmons were obtained using an electromagnetic approach and a hydrodynamic description of an electron liquid. Damped and amplified plasmon eigenmodes are studied numerically depending on the relationship of the magnitudes and directions of the direct electric current and the phase velocity of the plasmon.

scholarly journals Afforestation in Serbia in the period 1961-2007 with special reference to Austrian pine and Scots pine

2009 ◽  
pp. 115-134 ◽  
Author(s):  
Nenad Rankovic
Keyword(s):  
Special Reference ◽  
Scots Pine ◽  
Tree Species ◽  
Forest Policy ◽  
National Forest ◽  
Special Significance ◽  
Future Period ◽  
Action Programme ◽  
Relationship Of ◽  
The Relationship

The significance of afforestation in Serbia is high because only in this way the forest area can be increased and brought to the level which corresponds to the demands of the population. This is also indicated by the content of some documents, such as 'Professional base for the design of the National Forest Action Programme', which emphasises this problem from the very beginning. Special significance is assigned to afforestation with Austrian pine and Scots pine, which are most frequently applied in the afforestation of the most unfavourable terrains. This study analyses the scope of afforestation over the period 1961-2007, the percentage of Austrian pine and Scots pine and the relationship of the afforested areas, and generates the forecasts of the changes in the future period. In this way, the socialeconomic significance of afforestation can be assessed from the aspect of satisfying the objectives of forest policy, and particularly of afforestation with Austrian pine and Scots pine, as the specific tree species.

scholarly journals The method of determining the silvicultural and inventory indices of urban spaces with the use of the equations of communication

2018 ◽  
Vol 7 (4) ◽  
pp. 82-90
Author(s):  
Василий Ковязин ◽  
Vasiliy Kovyazin ◽  
Тхи Нгуен ◽  
Thi Nguen
Keyword(s):  
Species Diversity ◽  
Tree Species ◽  
Forest Inventory ◽  
Urban Spaces ◽  
Tree Age ◽  
Coefficient Of Determination ◽  
Relationship Of ◽  
First Time ◽  
The Relationship ◽  
Trees And Shrubs

The purpose of our research was to study the species diversity of trees and shrubs in the memorial Park across three centuries after its formation. Such research we carried out for the first time. In addition, we conducted measurements of forest inventory indices of the studied tree species. The calculated equation of the relationship of tree age with a height and diameter that can be measured. The mathematical models should be used to determine the age of trees, as the drill age is not recommended to use for traditional purposes in the memorial parks. The tightness of the obtained relations inventory indices in the form of a parabola is quite high. The coefficient of determination is 0.82 to 0.99, depending on the type of wood.

scholarly journals The most frequent powdery mildews on forest woody species and their impact

2005 ◽  
pp. 9-29 ◽  
Author(s):  
Dragan Karadzic ◽  
Tanja Milijasevic
Keyword(s):  
Powdery Mildew ◽  
Gypsy Moth ◽  
Natural Regeneration ◽  
Quercus Robur ◽  
Woody Species ◽  
Pedunculate Oak ◽  
Forest Trees ◽  
Fungus Species ◽  
Powdery Mildews ◽  
Oak Trees

The most frequent fungus species known as powdery mildews, causing the diseases of forest trees, were studied. Among forest woody species, oaks are especially susceptible to powdery mildew attack, and among them pedunculate oak (Quercus robur L) is highly endangered. This paper reports 49 species of powdery mildews. However, Microsphaera alphitoides has the greatest significance in forest economy, causing the decline of seedlings in nurseries and also aggravating the natural regeneration of pedunculate oak. This fungus, together with gypsy moth and honey fungus (Armillaria mellea) participates in the dying of old oak trees. Powdery mildews can be successfully controlled by fungicides, and sulphur fungicides Karatan and Rubigan are especially effective.

scholarly journals Producción de frutos de Gleditsia amorphoides (Griseb.) Taub. (Fabaceae) y abundancia de Bruchidius endotubercularis Arora (Coleoptera: Chrysomelidae) durante tres años consecutivos en el SE de la provincia de Formosa (Argentina)

2018 ◽  
Vol 66 (3) ◽  
pp. 1046 ◽  
Author(s):  
Claudia Marcela Godoy ◽  
Arturo Kehr ◽  
Graciela Lavia
Keyword(s):  
South America ◽  
Tree Species ◽  
Single Species ◽  
Fruit Production ◽  
Forest Trees ◽  
Viable Seeds ◽  
First Time ◽  
The Relationship

Gleditsia amorphoides (Griseb.) Taub. is a tree species native to South America. It is known for its good quality wood and for its fruits that contain a rubber for industrial uses. One of the causes for the reduction of the production of viable seeds in forest trees is the damage caused by predators of fruits and seeds. The relationship between fruit production and predators is not known for G. amorphoides. Therefore, in this study, we evaluated the fruit production in this three species and the abundance of specimens of the Subfamily Bruchinae associated to G. amorphoides. The study was carried out in three localities of the Formosa Province in the Northeast of Argentina for three consecutive years. We found a single species of Bruchinae, identified as Bruchidius endotubercularis Arora. The results showed the existence of variability in the production of G. amorphoides fruits between years, but not between locations. The abundance of insects remained constant, not responding to the variation in the production of fruits between years. In this study, we report for the first time, the occurrence of B. endotubercularis associated with G. amorphoides in Argentina

Effect of EAM Pulsed Current on 1450 MPA Martensitic Steel

2014 ◽  
Author(s):  
Megan A. Lobdell ◽  
John T. Roth ◽  
Chetan P. Nikhare ◽  
Dennie Parsons ◽  
Dae-Ho Yang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Electric Current ◽  
Martensitic Steel ◽  
Heat Treating ◽  
Pulsed Current ◽  
High Tensile Strength ◽  
Pulse Period ◽  
Lower Strength ◽  
Pulsed Electric Current ◽  
Current Duration

Martensitic steel is often used to fabricate parts that require high tensile strength. However, this quality, and the material’s low ductility, requires manufacturing equipment with higher tonnage capacity. This paper explores a potential way to reduce the tonnage requirement by temporarily reducing the steel’s required flow stress. Previous studies with other metals have shown that using a pulsed electric current will provide lower strength, as well as, an increase in ductility, without the sensitivity to temperature that heat treating has. This project investigates how martensitic steel reacts to pulsing electric current in terms of the tensile strength and elongation. The project consists of two studies. First, where the parameters considered were current density (CD), pulse duration (PD), pulse period (PP), and pressurized air (PA). Second is a series of tests where current duration was based off the material’s strength. The results from the first study show that the electricity can increase the material’s achievable elongation; the second study achieved reducing and limiting the material’s strength.

The relationship of tropical bird communities to tree species composition and vegetation structure along an Andean elevational gradient

2012 ◽  
Vol 40 (5) ◽  
pp. 950-962 ◽  
Author(s):  
Jill E. Jankowski ◽  
Christopher L. Merkord ◽  
William Farfan Rios ◽  
Karina García Cabrera ◽  
Norma Salinas Revilla ◽  
...  
Keyword(s):  
Species Composition ◽  
Tree Species ◽  
Vegetation Structure ◽  
Elevational Gradient ◽  
Bird Communities ◽  
Tree Species Composition ◽  
Tropical Bird ◽  
Relationship Of ◽  
The Relationship

scholarly journals THE RELATIONSHIP OF SELECTED NEAR FOREST FARMERS’ CHARACTERISTICS AND THEIR PARTICIPATIONS IN FOREST CONSERVATION AT PARUNG PANJANG, BOGOR

2006 ◽  
Vol 2 (4) ◽  
Author(s):  
Yayuk Siswiyanti ◽  
Basita Ginting S.
Keyword(s):  
Forest Fire ◽  
Low Income ◽  
Forest Conservation ◽  
Forest Products ◽  
Forest Trees ◽  
Independent Variables ◽  
Research Findings ◽  
Relationship Of ◽  
The Relationship ◽  
Age Category

Near forest village residents was one of the main forest share holders. So, they should be involved in various forest conservation efforts. Their involvements not only in activities to keep out people from illegal cutting of the forest trees or to put off forest fire, but also in replanting the forest and in other conservation activities. To improve these people welfare, a study on the villagers’ participation in forest conservation was needed. In this conjunction, the objectives of this study were: (1) to determine the villagers’ distributions on their selected characteristics, (2) to identify the villagers’ participation in the forest conservation, and (3) to determine the extent of relationships amongst the villagers’ characteristics and their participations in forest conservation. The population of the study was the residents of nine near forest villages in Parung Panjang sub-district, District of Bogor. The sample was 115 residents taken randomly from the population in those villages. In conjunction with this, this study was designed as a descriptive-correlation research. The independent variables were the villagers’ characteristics and some supporting factors; whereas the dependent variable was the villagers’ participations in the forest conservation. Data were collected through interviews with the villagers in February through April 2006. Descriptive statistic procedure was used to analyze the obtained data. The research findings pointed out that: (1) most of respondents involved in the study were in the older age category, of the Sundanese ethnic, low in education, had never received any training in forest conservation, low in forest conservation knowledge, mostly worked as up-land farmers for five hours daily, and had also low income, (2) their participations in planning, implementing, and evaluating forest conservation as well as in using the forest products were low, and (3) the extents of relationship amongst their characteristics included some supporting factors and their participations in forest conservation were either low or negligible.

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