Anaerobic Digestion Of Mixed Chemical Pulping And Palm Oil Mill Effluent In Suspended Growth Anaerobic Digester.

The feasibility of anaerobic digestion treating palm oil mill effluent (POME) with addition of chemical pulping wastewater (black liquor) was studied in semi-continuous fed digesters under thermophilic (55°C) condition. The anaerobic digestibility of POME with and without addition of black liquor (2.5% and 5% by volume) was compared. Black liquor is an effluent obtained from pulping processes and it has high toxicity level and poor biodegradability. The digesters contained POME without black liquor functioned as a control in this study. The chemical oxygen demand (COD) reduction for hydraulic retention time (HRT) of 5 days and 10 days were examined to evaluate the effect of HRT on the performance of the digesters. The results depicted that COD reduction could be achieved up to 87% in the digester without black liquor and 79% reduction in COD with black liquor added. Fourier Transform Infrared (FTIR) spectroscopy was used to identify the functional group of POME operated under thermophilic temperatures and with or without addition of black liquor. Differences in the functional group were depicted within ten days HRT for both conditions. The results of this work could be used as a basis to enhance the possibility of anaerobic digestion in treating the chemical pulping wastewater which is initially known difficult to degrade biologically

Study of Stress Evolution of Germanium Nanocrystals Embedded in Silicon Oxide Matrix

Germanium (Ge) nanocrystals had been synthesized by annealing co-sputtered SiO₂-Ge in N₂ and/or forming gas (90% N₂ + 10% H₂) at temperatures ranging from 700 to 1000°C from 15 to 60 min. It was concluded that the annealing ambient, temperature and time have a significant influence on the formation and evolution of the nanocrystals. We also showed that a careful selective etching of the annealed samples in hydrofluoric solution enabled the embedded Ge nanocrystals to be liberated from the Si oxide matrix. From the Raman results of the as-grown and the liberated nanocrystals, we established that the nanocrystals generally experienced compressive stress in the oxide matrix and the evolution of these stress states was intimately linked to the distribution, density, size and quality of the Ge nanocrystals.Singapore-MIT Alliance (SMA

Interleukin-13 Genetic Variants, Household Carpet Use and Childhood Asthma

10.1371/journal.pone.0051970PLoS ONE81

TEM Study on the Evolution of Ge Nanocrystals in Si Oxide Matrix as a Function of Ge Concentration and the Si Reduction Process

Growth and evolution of germanium (Ge) nanocrystals embedded into a silicon oxide (SiO₂) system have been studied based on the Ge content of co-sputtered Ge-SiO₂ films using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy. It was found that when the proportion of Ge relative to Ge oxide is 20%, TEM showed that annealing the samples at 800°C for 60 min resulted in the formation of a denuded region between the silicon/silicon oxide (Si/SiO₂) interface and a band of Ge nanocrystals towards the surface of the film. By introducing a 20nm thick thermal oxide barrier on top of the silicon (Si) substrate on which the film is deposited, no denuded region in the bulk of this sample is observed. It is proposed that this barrier is effective in reducing both Ge diffusion into the Si substrate and Si diffusion from the substrate into the film. Si diffusing from the Si substrate reduces the Ge oxide into Ge which can subsequently diffuse into the Si substrate. However, the oxide barrier is able to confine the Ge within the oxide matrix so that the denuded region in the bulk of the film cannot form. However the reduction in diffusion should be more significant for Ge as its diffusion coefficient is lower than Si due to its larger size. It is suggested that the denuded region consists of amorphous Ge diffusing towards the Si/SiO₂ interface. When the Ge content is increased to slightly more than 70%, TEM showed that Ge nanocrysyals formed after annealing at 800°C for only 30 min for samples with and without the oxide barrier. There is no denuded region between the Ge nanocrystals band and the Si/SiO₂ interface for both samples but it was observed that coarsening effects were more prominent in the film deposited on top of the oxide barrier. The reduction effect of Si on Ge oxide should not play a significant role in these samples as the Ge content is high.Singapore-MIT Alliance (SMA

Jet-quenching of the rotating heavy meson in a N{\mathcal{N}}=4 SYM plasma in presence of a constant electric field

In this paper, we consider a rotating heavy quark-antiquark ($q\bar{q}$) pair in a ${\mathcal{N}}$=4 SYM thermal plasma. We assume that $q\bar{q}$ center of mass moves at the speed $v$ and furthermore they rotate around the center of mass. We use the AdS/CFT correspondence and consider the effect of external electromagnetic field on the motion of the rotating meson. Then we calculate the jet-quenching parameter corresponding to the rotating meson in the constant electric field

Effect of heat exposure duration on the thermoluminescence of concrete

ACI Materials Journal904319-322AMAJ

Component allocation and ordering policy in a multi-component, multi-product assembled to stock system

10.1007/s00291-009-0166-7OR Spectrum322293-31

Component commonality in assembled-to-stock systems

10.1080/07408170500436724IIE Transactions (Institute of Industrial Engineers)383239-251IIET

Renal dysfunction in workers exposed to inorganic lead

Annals of the Academy of Medicine Singapore302112-117AAMS