Abstract: This paper presents a study on the thermodynamics
and transport properties of hot potassium carbonate aqueous system
(HPC) using electrolyte non-random two liquid, (ELECNRTL)
model. The operation conditions are varied to determine the system
liquid phase stability range at the standard and critical conditions. A
case study involving 30 wt% K2CO3, H2O standard system at
pressure of 1 bar and temperature range from 280.15 to 366.15 K has
been studied. The estimated solubility index, viscosity, water
activity, and density which obtained from the simulation showed a
good agreement with the experimental work. Furthermore, the
saturation temperature of the solution has been estimated.
Abstract: This paper proposes a new optimization techniques
for the optimization a gas processing plant uncertain feed and
product flows. The problem is first formulated using a continuous
linear deterministic approach. Subsequently, the single and joint
chance constraint models for steady state process with timedependent
uncertainties have been developed. The solution approach
is based on converting the probabilistic problems into their
equivalent deterministic form and solved at different confidence
levels Case study for a real plant operation has been used to
effectively implement the proposed model. The optimization results
indicate that prior decision has to be made for in-operating plant
under uncertain feed and product flows by satisfying all the
constraints at 95% confidence level for single chance constrained and
85% confidence level for joint chance constrained optimizations
cases.
Abstract: Two freshwater fishes, Rasbora sumatrana
(Cyprinidae) and Poecilia reticulata (guppy) (Poeciliidae) were
exposed for a four-day period in the laboratory condition to a range
of copper (Cu) and cadmium (Cd) concentrations. Mortality was
assessed and median lethal concentrations (LC50) were calculated.
LC50 increased with decrease in mean exposure times for both metals.
For R. sumatrana, LC50s for 24, 48, 72 and 96 hours for Cu were
54.2, 30.3, 18.9 and 5.6 μg/L and for Cd 1440.2, 459.3, 392.3 and
101.6 μg/L respectively. For P. reticulata, LC50s for 24, 48, 72 and
96 hours for Cu were 348.9, 145.4, 61.3 and 37.9 μg/L and for Cd
8205.6, 2827.1, 405.8 and 168.1 μg/L, respectively. Results indicated
that the Cu was more toxic than Cd to both fishes (Cu>Cd) and R.
sumatrana was more sensitive than P. reticulata to the metals.