Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : properties

Optimization Conditions for Preparation Of Polyvinyl Alcohol- Alumina Gel Composite and its Properties


Engineering and Technology Journal, 2010, Volume 28, Issue 20, Pages 6115-6127

A preparation of poly (vinyl alcohol) (PVA)/alumina (Al 2O3) gel
composite was investigated.
This type of composite gel was carried out with two stages firstly the
hydrolysis of polyvinyl alcohol in a hot water at 200ºC for 2 hours and different
mixing ratio of (PVA/H2O) solution at (10,20,30,40,50) wt% has been
investigated to check its operating conditions .Secondly different ratios of alumina
refractory were used (5,10,15,20,25) wt% of (AL2O3 /PVA) at 350ºC for 4 hours
to give a completes composite gel of ( PVA/Al2O3) in a polymerization stage.
The final composite gel of (Al2O3/PVA) is molded in a different shapes
and size due to suitable characteristics tests in order to check chemical, thermal,
and mechanical properties afterward curing these specimens at 120ºCfor 2 hours
to complete the compatibility of composite gel.
The results tests proved that: All final composite gel specimen is more
efficient than other base polyvinyl alcohol (PVA) of high mechanical and thermal
properties than base one with less internal stresses, also the resistance for chemical
solutions in (100%H2O, 10%H2SO4) is increased at sever conditions at 50ºC for
5 days especially for optimum mixing ratio specimen No.3 with preference for
optimum sample No.3 of (30%PVA Sol./15% Al2O3) g/g.

A Restriction Enzyme from Escherichia coli Purification and General Properties

Mukaram Shikara; Nadia Tariq Barakat; Maysem Modaffer Al-Obaidy

Engineering and Technology Journal, 2009, Volume 27, Issue 5, Pages 954-961

An endonuclease restriction enzyme has been purified from E. coli about 40-fold with
DNAse and RNAse recoveries of about 3%. The purification steps included precipitation
of the enzyme with ammonium sulphate, and reclaimed it through Sephadex G-100 and
DEAE-cellulose chromatography. The purified endonuclease was able to break lambda
DNA into three bands. The enzyme has 5% of carbohydrate moiety which means it is a
glycoprotein. Lastly, the comparison with other commercial restriction endonucleases
proves that this enzyme is a restriction enzyme with enzymic activity dependent on