In this research, several samples of silicon oxide were prepared in the form of aerogel and xerogel, starting from different raw materials and using different drying methods. Where a part of the samples was prepared using aqueous sodium silicate (gla
ss water) (Na2SiO3) as a raw material, which is an economical and cheap material, while the rest of the samples were prepared using tetraethoxysilane (TEOS). Some of these samples were surface modified before drying using Trimethylchlorosilane, which is high Price (TMCS) by replacing the surface silanol groups (Si-OH) with alkyl. As for the remaining samples, which were prepared without surface modification, we succeeded in obtaining aerogel with a lower preparation cost and very close characteristics to the samples prepared by surface modification.
The research aims to study is to study the effect of the pH factor of Pterocladia
capillacea on agar yield and some of its physical properties using different degrees of pH
(4- 5.5 - 5.5 - 6.5 - 7.5 - 7.5 - 8). The maximum yield of agar was 37.45%
at pH = 5 and
562g / cm2 and viscosity 10.7cP and 15.45% at pH = 8 with the highest strength of 768 g
/cm2 and viscosity of cP 156. The degree of melting and melting of agar Between (22-
33.5 οC) and (75- 86 οC), respectively.
The research aims to study the effect of Seasonal variations in yields and qualities
of agar seaweed Pterocladia capillacea. The results show that there is a clear impact of the
Seasonal variations in the yield, physical and chemical properties of
the extract agar.
Agar yields ranging from 10.1 to 33.8% and has been the highest in the month of June and
below 33.8% in December, 10.1% of the years 2014 to 2015. Reached the maximum value
of the strength of the gel in June, 789 g/cm2 and the minimum value of 183 g/cm2 through
December and the average rate of sulfates 3.42%. The viscosity values ranged between
35.7 and 81.4 cP, and recorded the highest value in July 81.4 cP. Melting temperature
ranged 78- 86.5 °C and Gelling temperature from 35 to 25 °C.
The research aims to study the effect of of agar extraction
temperature (80-90- 100-110 and 120) Syrian alga Pterocladia
capillacea on its yield and and some physical properties.
During this study, various types of silicon oxide were prepared
as aerogel and xerogel using multiple precursors and different
drying technics. Some of these samples were prepared from
Sodium silicate (waterglass) Na2SiO3 as a precursor which is a
cheap material, while others were prepared using tetraethoxysilane
(TEOS).
The objective of this study was to study and to analyze caffeine release from gel and
emulgel prepared from carbopol. The properties of the preparations were determined (e.g.
visual inspection, pH test, spreadability and in vitro release). The mech
anisms of caffeine
release were analyzed according to zero and first orders, and to Higuchi and Korsmeyer-
Peppas models. Results were analyzed statistically using student t-test.
The gels were transparent while emulgels were creamy, white and smooth. pH values
were suitable for dermal application and spreadability was not changed in both cases. On
the other hand, accumulated released amount of caffeine was decreased from emulgel in
comparison with the gel. The release pattern was in accordance with Higuchi equation and
n value referred that the diffusion was the main mechanism of release from the gel while
the relaxation and the erosion contributed importantly in the release of suspended caffeine
from emulgel.
The objective of this study was to prepare acceptable carbopol gels and to evaluate
the factors influencing the spreadability and release properties of a model hydrophilic
compound (caffeine). Results were analyzed statistically using student t-tes
t. The gels
were transparent at 1 and at 2% caffeine (with alcohol). Spreadability was decreased when
carbopol was increased and when caffeine quantity was changed (except at 2% carbopol).
Spreadability was affected statistically with change of cosolvent. Released caffeine
quantity (%) was increased with decreasing of carbopol quantity and increasing of caffeine
quantity introduced in the formula. Total caffeine quantity (%) was decreased with alcohol
presence. Caffeine release followed Higuchi pattern, e.g. diffusion was the principal
mechanism of caffeine release from these formulas.
The objective of this study was to compare Chlorhexidine gel 0,2%
with Clindamycine phosphate gel 1% when they applied topically
to protect of pain and dry socket after surgical extraction.
The thin films of TiO2 were prepared by the Sol-Gel, on glass
subtracts by using the following initial solutions: trichlorethylene
titanium, ethanol, sodium hydroxide and hydrochloric acid and
distilled water. The films were annealed at temperatur
es(200- 300-
400-500)c° for 1 hour. The structure of the prepared and annealed
films were studied by XRD. The XRD rusltes showed that the films
prepared crystallize according to orthorhombic Structure.Lattice
constants were calculated and it was found that it was consistent
with the data JPCDS and with some scientific works.
Seasonal changes effect on yield and quality of carrageenan from the Syrian
marine alga Hypnea musciformis were studied during 1 year. The carrageenan
yield varied from 31 to 46%. The maximum yield was recorded between April
and September, while l
ow carrageenant content was recorded in December.
The gel strength of carrageenan was maximum in September (260 g/cm²) and
minimum in March (90 g/cm²). The viscosity ranged from 22 to 44cP with a
peak recorded in September. Seasonal variations were not observed in the
gelling (42-50 C°) and melting (60-70 C°) temperatures of carrageenan. The
results indicate that Hypnea musciformis can be considered a good sources for
production of commercial carrageenan in future.
