BUKU ABSTRAK - Universiti Putra Malaysia

Manufacture and Application of Nano Silver Water Treatment Filters
Keywords: Nano silver, polypropylene water filter, bacteria
Mrs. Farideh Heidarpour
Faculty of Engineering, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 8519; f.heidarpour@yahoo.com
A Backward Fault Recovery Mechanism in Preemptive Utility Accrual Real Time
Scheduling Algorithm
Mrs. Idawaty Ahmad
Shamala Subramaniam, Mohammad Othman and Zuriati Zulkarnain
Faculty of Computer Science and Information Technology, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 6541; idawaty@fsktm.upm.edu.my
Keywords: Real time schedulling algorithm, TUF/UA scheduling paradigm, discrete event simulation
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Science, Technology & Engineering
Advancements in nanotechnology are being applied in the water-purification industry, to keep harmful
bacteria out of drinking water. Due to its bactericidal properties, nano-silver is used in many products as an
antibacterial function. This study aimed to produce and investigate the effect of a nano silver-based watertreatment
using polypropylene filter via the physical vapor deposition method. The production of nano silver filter
used the Balzers 760 machine which was equipped with an electron beam gun ESQ 110. The Balzers machine
was modified in order to enable coating of the cylindrical filters in a homogenous manner. The nano-silver
particles were made by electron beam bombardment of the silver metal, which were subsequently deposited
on the polypropylene filter evenly. The thicknesses of the nano layer coated on the filters were about 35.0nm,
45.0nm and 55.0nm in average, respectively and were determined by scanning electron microscopy, atomic force
microscopy and the X-ray diffraction technique. The inductively coupled plasma/mass spectrometry (ICP/MS)
was used to determine amount of silver nano-particles in water sample after filtration. The results found that
the count of nano silver particles which the enumeration of bacteria was done by membrane filter method in the
filtered water sample was nil. At a flow rate of 3L/hr and after four hours filtration, more than 99% Escherichia
coli were inactivated when the input water had a bacterial load of 103 colony-forming units (CFU) per mL. SEM
photos were showed the filtered bacteria on the NSF after passing through the polluted water. This is the first
report on the manufacture of nano silver cylindrical polypropylene filter using the electron beam gun technique,
to the best of our knowledge. The filter system produced in this work has the potential to be used as an efficient
and cost-effective water treatment method.
This study proposed a robust algorithm named as Backward Recovery Preemptive Utility Accrual Schedulling
(BRPUAS) algorithm that implements the Backward Recovery (BR) mechanism as a fault recovery solution
under the existing utility accrual schedulling environment. The problem identified in the TUF/UA schedulling
domain is that the existing algorithms only consider the Abortion Recovery (AR) as their fault recovery solution
in which all faulty tasks are simply aborted to nullify the erroneous effect. The decision to immediately abort the
affected tasks is inefficient because aborted tasks produce zero utility causes the system to accrue lower utility.
The proposed BRPUAS algorithm enabled the re-execution of the affected tasks rather than abortion to reduce
the number of aborted tasks in the existing algorithm known as Abortion Recovery Preemptive Utility Accrual
Scheduling (ARPUAS) algorithm that employed the AR mechanism. The BRPUAS ensures the correctness of the
executed tasks in the best effort basis in such a way that the infeasible tasks are aborted and produced zero utility,
while the feasible tasks are re-executed to produce positive utility and consequently maximised the total accrued
utility to the system. The performances of these algorithms are measured by using discrete event simulation. The
proposed BRPUAS algorithm achieved higher accrued utility compared to ARPUAS for the entire load range.
Simulation results revealed that the BR mechanism is more efficient than the existing AR mechanism, producing
higher accrued utility ratio and less abortion ratio making it more reliable and efficient for adaptive real time
application domain.