ISSN 1556-6757


SJI 


 

 

 

 

 

 
 

Volume 2, Issue 1, 2009

 
 

Singing sands, musical grains and booming sand dunes

A. J. Patitsas

Abstract
The origin of the acoustic emissions from a bed of musical grains, impacted by a pestle, is sought in a boundary layer at the leading front of the pestle. The frequencies of the shear modes of vibration in such a layer are compared with the observed frequencies. It is assumed that such a layer is the result of the fluidization of the grain asperities due to the high stress level at the front end. Such a boundary layer can also account for the emissions from plates of sand sliding on a dune surface and from grains shaken in a jar.  Full Article




 

Synthesis and Degradation Studies of Nematic (N*) Liquid Crystals
Zohra N. Kayani, Saira Riaz, Shahzad Naseem

Abstract
Cholesteric Liquid Crystals (LCs) are synthesized and characterized for their optical properties.
The optical properties of cholesteric LCs have been investigated with varying applied field and
time. The electric field is applied in the range of 0V – 13V, whereas time is varied between a few
seconds and 95 minutes. These cholesteric LCs are aged at room temperature as well as at
higher temperatures up to 70oC. Degradation of these cholesteric LCs under different conditions
is also reported in this paper. Multi-step purification process was carried out and both the filtrate and residues are analyzed for phase identification. XRD analysis confirms the presence and absence of the main ingredients in the solution as well as in the residue.  Full Article

 

 

 

 

Hydrocarbon Degradation Potentials of Indigenous Fungal Isolates from Petroleum Contaminated Soils  Uzoamaka George-Okafor, Floretta Tasie, Florence Muotoe-Okafor

 

 

Abstract
Twelve fungal isolates recovered from oil-contaminated soils were screened for crude oil
biodegradation activity in a shake-flask culture. Among the twelve fungal isolates, only eight
showed potentials for biodegradation. Of these eight isolates, two of them identified as
Aspergillus versicolor and Aspergillus niger which exhibited the fastest onset and highest extent
of biodegradation were selected for further study on specific polycyclic aromatic hydrocarbon
(PAH) biodegradation. Both isolates exhibited above 98% degradation efficiency for polycyclic
aromatic hydrocarbon moieties when grown in a culture medium incorporated with 1% crude oil
(hydrocarbon) and 0.1 %Tween 80 for 7 days. Full Article