Department of Crop Sciencehttp://ir.lib.ruh.ac.lk/xmlui/handle/iruor/74702024-03-29T00:18:02Z2024-03-29T00:18:02ZUse of Crop Plants for Removal of Toxic Metals.Arunakumara, K.K.I.Uhttp://ir.lib.ruh.ac.lk/xmlui/handle/iruor/115272023-07-25T09:00:01Z2011-01-01T00:00:00ZUse of Crop Plants for Removal of Toxic Metals.
Arunakumara, K.K.I.U
Phytoextraction is an environmentally sound and cost-effective technology
for cleaning up soils contaminated with toxic metals. The success of phytoextrac tion depends on the ability of plants to produce large amounts of biomass. In addi tion, plants must be tolerant to the target metals and be efficient to translocate metals
from roots to the aboveground organs. The effectiveness of phytoextraction also
depends upon site and metal species. However, the amount of metals extracted by
plants is basically decided by (1) the metal concentration in dry plant tissues and
(2) the total biomass of the plant. Certain varieties of high-biomass crops have been
found to have the ability to clean up the contaminated soils. The major advantage of
using crop plants for phytoextraction is the known growth requirements and well established cultural practices. One of the most promising, and perhaps widely
studied crop plant for the extraction of heavy metals is Indian mustard. Other crops
like sweet sorghum, oat, barley, maize, and sunflower are also reported to accumulate
toxic metals. As established cultural practices may not elicit the same plant response
as observed under non-contaminated conditions, attention must be paid on develop ing suitable agronomic practices to optimize the growth of plants even under con taminated conditions. Further, a coordinated effort is required to collect and preserve
germplasm of accumulator species where molecular engineering can play a key role
in developing engineered plants capable of cleaning up contaminated soils and
commercializing phytoextraction strategies
2011-01-01T00:00:00ZIdentification of joint efficiencies in 13 mm finger jointed timber species used in Sri Lanka.Muthumala, C.KDe Silva, SArunakumara, K.K.I.UAlwis, P.L.A.Ghttp://ir.lib.ruh.ac.lk/xmlui/handle/iruor/115012023-07-27T07:10:51Z2018-01-01T00:00:00ZIdentification of joint efficiencies in 13 mm finger jointed timber species used in Sri Lanka.
Muthumala, C.K; De Silva, S; Arunakumara, K.K.I.U; Alwis, P.L.A.G
When using timber in construction and the furniture manufacturing industry, waste timber materials and short length sections of timbers which are dumped by sawmills are considered to be matter of concern. ‘Finger joint’ is a recognized technique connecting two small pieces of waste timber together to ensure their sustainable utilization. Currently, the technique is used in Sri Lanka for non- structural purposes such as making timber boards and furniture. However, issues related with the strength of the joints have not fully investigated in Sri Lanka. This study was undertaken to determine the tensile strength performance of seven timber species in both unjointed (clear) and finger-jointed methods with 13mm finger pitch. An SWR adhesive (PVA) type was used as bonding material at normal exposure conditions. Well-seasoned Grandis, Jack, Kumbuk, Mahogany, Pine, Satin and Teak timber materials were used for the study.
BS 373: 1957 and BS EN 15497:2014 were used as standards for tests. The tests for tensile properties were performed using the Universal Testing Machine (UTM 100 PC) with a loading plate moving speed of 01mm/min. Maximum load was read on graph to calculate the ultimate tensile strength.
The highest ultimate average tensile strength values were recorded in control specimens and different joint efficiencies were recorded in different finger jointed species. The highest mean finger joint efficiency percentage was obtained from Mahogany timber species and the least mean finger joint efficiency percentage was recorded in Kumbuk timber species.
2018-01-01T00:00:00ZInvestigation of the Relationship Between Densities Versus Mechanical Properties of Sri Lankan Timber Species.Muthumala, C.KDe Silva, SArunakumara, K.K.I.UAlwis, P.L.A.Ghttp://ir.lib.ruh.ac.lk/xmlui/handle/iruor/114982023-02-27T07:08:19Z2020-01-01T00:00:00ZInvestigation of the Relationship Between Densities Versus Mechanical Properties of Sri Lankan Timber Species.
Muthumala, C.K; De Silva, S; Arunakumara, K.K.I.U; Alwis, P.L.A.G
The aim of this study was to investigate the relationships among wood
density, modulus of rupture (MOR), modulus of elasticity (MOE), compression
parallel to grain (CNP) and compression perpendicular to grain (CPG) in 32 timber
species grown in Sri Lanka. Defects free stem section from each timber was taken
at the breast height and samples were prepared according to BS 373: 1957 standard.
The tests for mechanical properties were performed through the Universal Testing
Machine (UTM 100 PC). Linear Regression Analysis was done for interpreting the
effectiveness of the relationship in wood density with other mechanical properties
(MOR, MOE, CPG, CNG). The relationship between wood density and mechanical
strength properties were analyzed by regression models.Wood density showed strong
positive relationship with CPG and MOR. Results in the regression test revealed a
significant relationship (P = 0.001) among wood density and other mechanical prop erties such as MOR, MOE, CNP and CPG. These results can be used for developing
effective timber classification system in Sri Lanka
2020-01-01T00:00:00ZInvestigation of the Best Joint Type for Combining of the Finger-Jointed Timber Panels in Board Production.Muthumala, C.KDe Silva, SArunakumara, K.K.I.U Alwis, P.L.A.Ghttp://ir.lib.ruh.ac.lk/xmlui/handle/iruor/114932023-02-27T07:08:57Z2020-01-01T00:00:00ZInvestigation of the Best Joint Type for Combining of the Finger-Jointed Timber Panels in Board Production.
Muthumala, C.K; De Silva, S; Arunakumara, K.K.I.U ; Alwis, P.L.A.G
Waste sawn timber material in furniture factories and short length of sawn
timber are serious problems in timber industry. To further suggest ways to minimize
the waste, by applying a jointing system, this paper utilizes the finger-jointed tech niques. Using this method, waste timber planks, trimmings and edgings can be used
as finger-jointed boards and furniture in sustainable way. Finger joint technique is
also used to eliminate wood defects which weaken the strength of sawn wood planks.
Finger joint technology is used in structural and non-structural applications. Furniture
mainly belongs to non-structural category. This study was conducted to investigate
the best joint type for combining of the finger-jointed timber panel in board produc tion. Shear test was done to determine the most suitable joint type which could be
employed in combining two finger-jointed timber panels. Shear test was performed
for Pine—Pinus carebaea (soft wood) and Teak—Tectona grandis (Hard wood)
timber types. Clear specimens, butt-jointed and tongue and groove were tested in
the shearing apparatus. Eight test specimens of each timber specimens were used
to obtain shear strength perpendicular to grains with 0.5 mm/min loading rate was
applied using a Universal Testing Machine. Shear strength of Teak specimens with
tongue and groove is higher than Teak specimens with butt joint, because bonding
area of the tongue and groove specimens is higher than bonding area of the butt jointed specimens. Specimen part with tongue of Pine is weaker than corresponding
part of butt-jointed Pine specimen due to small cross-sectional area of tongue. So,
Shear strength of Pine specimen with butt joint is greater than Pine specimen with
tongue and groove.
2020-01-01T00:00:00Z