MESII - 2017http://dl.lib.uom.lk/handle/123/171812024-03-29T13:50:39Z2024-03-29T13:50:39ZDevelopment of a low cost, static light scattering based nano-particle size analyzerAnuradha, SKAIshan, HHAAmarasinghe, DAShttp://dl.lib.uom.lk/handle/123/173772022-06-21T09:22:39Z2017-03-01T00:00:00ZDevelopment of a low cost, static light scattering based nano-particle size analyzer
Anuradha, SKA; Ishan, HHA; Amarasinghe, DAS
Sivahar, V
A machine based on Static Light Scattering theories was developed for the cost effective and
efficient Quality Control of the average particle size of nano-particles used in different
manufacturing industries. In particular the instrument was adapted to measurement of carbon black
filler used in rubber compounding. Carbon blacks are amorphous quasi graphitic particulates of the
nanometer scale whose mean particle size affects the reinforcement, conductivity pigmentation and
UV resistance properties of the rubber. The instrument would enable local rubber compounding
companies to independently monitor and control the average particle size of the filler.
The system is semi-autonomous and measures approximately 29cm × 23cm × 17.5cm and weighs
approximately 4.2 kg. The instrument accepts a solution of nano-particles. Adjusts the solution
concentration automaticallyand measures the scattered intensity of light which it used to calculate
the particle size.
The system comprises of a fluidics module that handles the pumping and dilution of solutions, an
optics module that generates and detects the light and a control & power supply module that
operates the other components and supplies the right voltages to them. These modules are housed
in a corrosion protected steel frame and an aesthetically appealing enclosure.
Key features of the instrument are a self diagnostic system, a modular structure, a graphical user
interface with record keeping facility and extendibility to other particle size control applications. It
is of a modular design and has been constructed with the ease of maintenance and accessibility to
internal hardware, and manufacturability in mind. The components selection was based on the
optimization of performance parameter, size and cost. Mechanical, thermal and vibration stabilities
were considered in the design.
2017-03-01T00:00:00ZDesign of a Dynamic Mechanical Analyser for Rubber CompoundsHerath, HMRCRodrigo, IJWeragoda, VSChttp://dl.lib.uom.lk/handle/123/173762022-09-13T03:42:20Z2017-03-01T00:00:00ZDesign of a Dynamic Mechanical Analyser for Rubber Compounds
Herath, HMRC; Rodrigo, IJ; Weragoda, VSC
Sivahar, V
Dynamic mechanical analysis (DMA) is a powerful technique for characterization of the
viscoelastic properties of polymers such as thermoplastics, composites, thermosets and elastomers
in the form of sheet specimens, films, fibers, coatings or adhesives. DMA instruments measure the
modulus (stiffness) and damping (energy dissipation) properties of materials as they are deformed
under dynamic stress. When a polymeric material is subjected to a cyclic sinusoidal stress within
the viscoelastic region, the corresponding strain in the material would be out of phase due to the
delayed response of the viscous portion of the material. This phase difference corresponds to the
frequency of the force application and this is a unique characteristic of the polymer material.
Amplitude of the strain curve and phase shift between stress and strain curves are usually
identified as basic parameters.
In this design which is based on the ISO 6725 standard, forced vibration method was used and the
vibrations are impacted by the inertia force of an eccentric rotating mass is used to generate
sinusoidal force. Multi stress and multi frequency modes are operated by adjusting eccentricity
and speed of rotating mass. The instrument also has facility to adjust the static force imparted on
the specimen. Deformation of the material is detected by a displacement sensor. This design
satisfied all requirements of the testing standard.
2017-03-01T00:00:00ZDevelopment of antimicrobial materials for food packaging applicationsSenarath, SMNSMadushani, SPASamarasekara, AMPBAmarasinghe, DAShttp://dl.lib.uom.lk/handle/123/173752022-06-21T09:23:19Z2017-03-01T00:00:00ZDevelopment of antimicrobial materials for food packaging applications
Senarath, SMNS; Madushani, SPA; Samarasekara, AMPB; Amarasinghe, DAS
Sivahar, V
The rising demand to increase fresh food shelf life as well as the need of protection against foodborne
diseases urged the development of antimicrobial food packaging. Nanomaterials have
increasingly being used in food packaging applications in recent years due to their extraordinary
properties when compared to bulk materials. Nanoparticles provide signi? cant antimicrobial
properties in different environmental conditions. Nowadays, there is heighten attention in
designing nano particles incorporated food packaging with the introduction of nanotechnology.
Silver nanoparticles (AgNPs) based antimicrobial packaging is an innovative form of food
packaging used to extend shelf-life of food and reduce the risk of pathogens. AgNPs are one of the
most powerful antimicrobial agents which can be used for increasing shelf life of foods due to its
capacity to eliminate infectious micro-organisms. The present research work is based on the
preparation of silver nanoparticles incorporated coating for polymer based packaging components.
Nano Silver impregnated cross-linked polyvinyl alcohol coating was synthesized and applied on
the polymer surface. In this study, wettability of the polymer surface was enhanced by a UV
treatment. Contact angle was measured to confirmation of the wettability. The adhesion of the
coating to polymer was obtained as load required to peel off the coating. Optimum UV treatment
time was selected by using contact angle measurements and load required to peel off the coating.
Thermal degradation of cross-linked Nano silver coating was determined using thermo gravimetric
analysis. Presence of silver nanoparticles in the coating was confirmed by Surface Plasmon
Resonance (SPR) and Scanning Electron Microscopy (SEM). The nano silver incorporated
polymer was tested for its biocidal action against model bacteria Escherichia coli using zone
inhibition and food contain in nano silver coated containers. Developed nano silver incorporated
polymer based food packaging products showed antimicrobial properties. This developed product
can be used to improve the quality of the food and extend shelf life especially in food packaging
applications.
2017-03-01T00:00:00Zdevelopment of CZTS based solar cellDilshan, HADIWeerasinghe, WDDAttygalle, Dhttp://dl.lib.uom.lk/handle/123/173742022-06-21T09:22:55Z2017-03-01T00:00:00Zdevelopment of CZTS based solar cell
Dilshan, HADI; Weerasinghe, WDD; Attygalle, D
Sivahar, V
The two semiconductor layers Cu2ZnSnS4 (CZTS) and CdS were successfully
fabricated using economical, solution-based fabrication techniques. CZTS thin
film fabrication was done by spin coating technique onto soda-lime glass
substrates at rotating speed of 2000 to 6000 rpm. It was found that the optimum
precursor solution temperature is 38
o
C-42
o
C. The films dried at 140
o
C-160
o
C
and annealed in air at 280
o
C have shown a band gap in the range of 1.45 to
1.55eV. Cadmium Sulfide (CdS), the n-type semiconductor heterojunction partner
for CZTS was also deposited with good thickness control and uniformity in the
range of 50-100nm range. Chemical bath deposition method was utilized for CdS
thin film fabrication and the CdS thin film with optimum properties was obtained
at the conditions of 40
o
C-45
o
C temperature range and thickness variations were
also apparent with the number of coatings applied and the fabrication time. The
annealing temperature was found to be critical within the range of 180
o
C-220
o
C
(30 mins) for the optimization of CdS bandgap. CdS thin film fabricated under
optimum conditions has shown a bandgap range of 2.30eV-2.50eV. Successful
deposition on Fluorine doped Tin Oxide (FTO) glass substrate, reveals a feasible
route to fabricate superstrate type photovoltaic cell.
2017-03-01T00:00:00Z