8,857 research outputs found
Analyzing and Revisioning the Service Reduction Plan of Pierce Transit in Respect of Transit Equity
https://digitalcommons.tacoma.uw.edu/gis_projects/1048/thumbnail.jp
Enhancement Of Volatile Fatty Acid Production From Anaerobic Treatment Of Palm Oil Mill Effluent
Biological treatment unit is widely used to treat high organic content
wastewater such as palm oil mill effluent (POME). A treatment that can salvage the
useful nutrient from the wastewater is needed to enhance the sustainability of the
wastewater treatment process. Volatile fatty acid (VFA) has high potential to be
applied on many application such as production of biogas or biodegradable plastic.
The recovery of nutrient in the form of methane gas (end-product of anaerobic
digestion) was well researched but the study on the enhancement of volatile fatty acid
(VFA) (intermediate-product of anaerobic digestion) was still limited. VFA production
is preferred over biogas production because VFA can be used to produce more valuable
product such as polyhydroxyalkanoate (PHA) (a type of biodegradable plastic). The
enhancement of VFA production was achieved through the elimination of
methanogenesis process. In this study, a sequencing batch reactor was used to enrich
the biomass in partial anaerobic treatment of POME to enhance the VFA production.
The SBR has a working volume of 8 L and hydraulic retention time of 5 days. The
influent concentration of POME contains about 33400 mgCOD/L. The anaerobic
reactor managed to increase the VFA accumulation to about 10500 mg/L total VFA
(about 43.8 % of VFA accumulation in the feed). The microbial population analysis
had revealed that the growth of methanogen was suppressed and no methane gas was
release during the treatment process. Further, it was discovered that the increase of
ammoniacal nitrogen has increased the total VFA production. About 105.7 % VFA
accumulation was achieved at COD:N ratio of about 40:5. However, inhibition on the
VFA production occurred at ammoniacal nitrogen content of more than 4000 mg/L
shock loading. Furthermore, the effluent from the VFA enhancement reactor was used
as the feed to produce PHA. The aerobic reactor accumulating PHA using VFA
enriched POME (AE1) has achieved output PHA concentration of about 3773
mgPHA/L (specific production of about 0.32 mgPHA/mgVSS). The results shows that
the recovery of the VFA has high potential to produce biodegradable plastic (PHA).
Additionally, the microbial growth kinetics was evaluated for the microorganism in
VFA enhancement reactor and PHA production reactor. The result of the growth
kinetics studies was used to simulate the VFA accumulation and the PHA production
by using MATLAB software
A theoretic model for sonogenetic antiarrhythmia
Sonogenetics can be used as a new alternative for treating arrhythmia due to
its advantages of noninvasive, high safety and strong penetration. In the
treatment of arrhythmias by sonogenetics, cardiac myocytes are deformed by
ultrasonic radiation force. We quantitatively calculated the shape variation of
cardiomyocytes under ultrasonic radiation force, and the deformation of
cardiomyocytes caused the change of membrane tension. Membrane tension consists
of two parts, plasma membrane tension and cortical tension between the cell
membrane and cytoskeleton. Since plasma membrane tension was mainly considered
in existing experiments, we proposed a quantitative model of the relationship
between ultrasonic radiation force and plasma membrane tension. The Boltzmann
relationship between plasma membrane tension and ion channel opening
probability is presented based on the experimental results of ion channel
activation by stretching. Finally, a quantitative model was obtained for
ultrasonic radiation force to regulate the opening probability of ion channel
activated by stretching. Based on this quantitative model, we proposed the
regulation mechanism of ultrasonic radiation force under hypercompression and
hyperstretching, and verified that this mechanism can eliminate arrhythmias by
sonogenetics.Comment: 13pages,5 figure
Bis(μ-5-carboxybenzene-1,3-dicarboxylato)-κ3 O 1,O 1′:O 3;κ3 O 3:O 1,O 1′-bis[(2-phenyl-1,3,7,8-tetraazacyclopenta[l]phenanthrene-κ2 N 7,N 8)lead(II)]
In the title compound, [Pb2(C9H4O6)2(C19H12N4)2], the PbII atom is five-coordinated by two N atoms from a chelating 2-phenyl-1H-1,3,7,8-tetraazacyclopenta[l]phenanthrene (L) ligand and three O atoms from two Hbtc ligands (H3btc is benzene-1,3,5-tricarboxylic acid), resulting in a distorted PbN2O3 coordination. Two PbII atoms are bridged by the Hbtc ligands, forming a discrete centrosymmetric dinuclear complex. Intermolecular N—H⋯O and O—H⋯O hydrogen bonds and π–π interactions between the pyridine and imidazole rings, and between the pyridyl rings of the L ligands [centroid–centroid distances = 3.600 (6) and 3.732 (6) Å] lead to a three-dimensional supramolecular structure
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