Google+ Followers

Entri Populer

Siswa Link

GIT blog Chatami blog Conchita blog Photoholic blog Tiar Faisal blog Filli blog Paskibra NETIMA blog Wafa Yunie Blog PMR Netima OSIS Netima Blog Pramuka Netima Blog Ekstrakulikuler Netima Blog Giltrun
Blog Suci A Blog Kevin Blog Bintang Gaul Blog Rajin donk Blog Kevin Blog Reena Nur Blog Muammar Blog Herlina Blog Paulus S Blog Nanda MU Blog Mutiara Blog Ghina Islamiaty Blog Frida Meidiana Blog Thesa Nadya Blog Halida LH Blog Danang Blog Terra Anjani Blog Nuke Lusiana Blog Wilda Robiatul A Blog Ratna Eriyanti Blog Disy & Egis Blog Anna Afifah Blog Frida,Devi,Adzani,Tessya Blog Billy Agasi Blog Niki Pinastika Fahira Blog Fazrin Andhika Slamet Firdaus Blog Dandy Kurnia Blog Mudhoffar Fauzarrahmat Blog Bayu Nanda Prasetio Blog Rahayu Setia Yulandari Taska Blog Nindya Amalia Putri Blog Rizqi Agung Wibawa Blog Dehan Gunarsa Blog Tessya Noorrachmi Blog Adzani Oktoisya arya Blog Bayu Nanda Prasetyo Blog Dandy Kurnia Blog Herlina Blog Mudhoffar Fauzarrahmat Blog Nindya Amalia Putri Blog Rahayu Setia YT. Blog Rizqi Agung Wibawa Blog Bagas Satriyo W Blog Billy Agasi Blog Devi Fitriah Blog Elimia Solihat Blog Fadlli Ash-Shidiqqy Blog Fajar Bagja GW Blog Hedianto Dwi Kusumah Blog Lamhot Parluhutan T. Blog Monica Areza Putri Blog Muhamad Fauzan A. Blog Nadya Sofia SS. Blog Niki Pinastika Fahira Blog Ulfy Yunisha Blog Virda Qustiani H. Blog Titim Blog Alan Cantrani Budiman Blog Putri Awan Blog Silvi Maryanti Blog Nenden Ayu Noviyanti Blog Sri Indriani Blog Ghita Nurhalisa Blog Andini Blog Nida Aulia Blog Salma Aulia S

Pengunjung

widgeo.net

Peringkat

Top DSPI - Direktori Situs Pendidikan Indonesia Terbaik


2016 MotoGP Schedule

Yo Kita Belajar TIK-PTD Results

MotoGP 2013 
April 07
Qatar (Losail Circuit)

MotoGP 2013 
April 21 
Portugal (Estoril)

MotoGP 2013 
May 05 
Spain (Jerez)

MotoGP 2013 
May 19 
France (Le Mans)

MotoGP 2013
June 02 
Italy (Mugello)

MotoGP 2013 
June 16 
Catalunya (Circuit de Catalunya)

MotoGP 2013 
June 29 
Netherlands (Assen)

MotoGP 2013 
July 14 
Germany (Sachsenring)

MotoGP 2013 
July 21 
United States (Mazda Raceway)

MotoGP 2013 
August 18 
Indianapolis (Indianapolis)

MotoGP 2013 
August 25 
Czech Republic (Automotodrom Brno)

MotoGP 2013 
September 01 
Great Britain (Silverstone)

MotoGP 2013 
September 15 
San Marino & Riviera di Rimini (Misano)

MotoGP 2013 
September 29 
Aragon (Motorland Aragon)

MotoGP 2013 
October 21 
Malaysia (Sepang Circuit)

MotoGP 2013 
October 20 
Australia (Phillip Island)

MotoGP 2013 
October 27 
Japan (Motegi)

MotoGP 2013 
November 10 
Valencia (Comunitat Valencia)

Sabtu, 19 November 2011

The structure of wood (II)

Wood has extreme anisotropy because 90 to 95% of all the cells are elongated and vertical (i.e. aligned parallel to the tree trunk). The remaining 5 to 10% of cells are arranged in radial directions, with no cells at all aligned tangentially. The diagram below shows a cut-through of a tree trunk:

A cut-through of a tree trunk
In the trunk there are three main sections, the heartwood, which is physiologically inactive, the sapwood, where all conduction and storage occurs, and the bark, which protects the interior of the tree trunk. The two main types of tree, softwoods and hardwoods, have distinct internal structures. Coniferous trees are softwoods, with vertical cells, tracheids, 2 to 4 mm long and roughly 30 μm wide. These cells are used for support and conduction; they have an open channel and a thin cell wall:

Cross-section of tracheid cell typical of a softwood
The storage cells, parenchyma, are found in the radial direction. Scots pine is an example of a softwood tree. Below is shown a 3D model of the trunk interior of Scots pine made from micrographs of sections cut in the tangential, radial and transverse planes:


Broad-leaved trees are called hardwoods. The vertical cells in hardwoods are mainly fibres, which are 1 to 2 mm long and 15 μm wide. These are thick-walled with a very narrow central channel and are for support only.

Cross-section of fibre cell found in hardwoods
These cells are unsuitable for conduction, and so the tree needs vessels for this purpose. Vessels are either xylem, which are dead cells that carry water and minerals, or phloem, which are live cells and transport energy sources made by the plant. Vessels are 0.2 to 1.2 mm long, open-ended and are stacked vertically to form tubes of less than 0.5 mm in diameter. Hardwoods also have a small number of tracheid cells, and parenchyma cells are still present radially for storage. Both balsa and greenheart wood are examples of hardwoods. Below is shown a 3D model of the trunk interior of greenheart made from slides taken in the tangential, radial and transverse directions:


Sumber : http://www.doitpoms.ac.uk/tlplib/wood/structure_wood_pt2.php

0 komentar

Poskan Komentar