Volume 14 (2012): Issue 1 (March 2012)

The purpose of this analysis is to determine the uncertainties originating due to the kinetic parameters of the rate of a reaction proposed kinetic model. A kinetic model consisting of 208 reaction steps and 73 species was adopted for analysis. In the required uncertainty analysis, the accuracy of approximate models, generated by the Chemkin 4.1.1 for pollutant species, is determined. The reactions which contribute the uncertainty in the output concentrations of the pollutnats species formed in the combustion chamber were identified. The percentage contribution to the uncertainty in the output concentrations of pollutants were also determined.

This work focuses on the modeling, simulation and control of particle size distribution (PSD) during nanoparticle growth with the simultaneous chemical reaction, nucleation, condensation, coagulation and convective transport in a high temperature reactor. Firstly, a model known as population balance model was derived. This model describes the formation of particles via nucleation and growth. Mass and energy balances in the reactor were presented in order to study the effect of particle size distribution for each reaction mechanisms on the reactor dynamics, as well as the evolution of the concentrations of species and temperature of the continuous phase. The models were simulated to see whether the reduced population balance can be used to control the particle size distribution in the high temperature reactor. The simulation results from the above model demonstrated that the reduced population balance can be effectively used to control the PSD. The proposed method "which is the application of reduced population balance model" shows that there is some dependence of the average particle diameter on the wall temperature and the model can thus be used as a basis to synthesize a feedback controller where the manipulated variable is the wall temperature of the reactor and the control variable is the average particle diameter at the outlet of the reactor. The influence of disturbances on the average particle diameter was investigated and controlled to its new desired set point which is 1400nm using the proportional-integral-derivative controllers (PID controllers). The proposed model was used to control nanoparticle size distribution at the outlet of the reactor.

The paper summarizes the results from twenty model tests of continuous one-stage mesophilic anaerobic co-digestion of cattle slurry (90 wt. %) and various biowastes (10 wt. %). Digestion was conducted in 0.06 m³ reactors with hydraulic retention times ranging from 60 to 98 days during the research period 2007-2010. Methane production intensity and specific methane production are discussed. The highest methane production intensity (0.85 m_N³.m^-3.d^-1) was from a mixture of 63 wt. % of total solids from biscuit meal EKPO - EB and from 37 wt. % of total solids from cattle slurry. The highest specific methane production from 1 kg of added organic compounds (0.67 m_N³.kg_VSp^-1) was given by a mixture containing 61 wt. % of total solids using spring barley Aksamit (milled grain) and 39 wt. % of total solids from cattle slurry. The highest substrate-specific methane production (0.92 m_N³.kg_VSp^-1) was from milled grains of winter rye Aventino.

The aim of this study is the evaluation of the effect of chemical treatment of jute fibres on their permeability with polyester resin and determination of optimal treatment parameters. Unmodified jute fabric by LENTEX, Poland and polyester resin ESTROMAL 14 were used in the experiments. NaOH and KOH water solutions (various concentration - from 1 to 15% - and treatment duration - from 0.5 to 6h), vinyl acetate, methanol, toluene diizocyanate were used for the treatment. Determination of the effect of the chemical treatment on fiber-resin interaction was made in: infiltration of resin into reinforcement structure tests and fabric absorbability tests. Three criteria: time of penetration of resin into the reinforcing fabric, fabric absorbability and the area of a part of the specimen cross-section penetrated with the resin were taken into account. The fabrics treated with 1-5% - long-time and 15% short-time NaOH and KOH water solutions showed the best results within the tested criteria. These results do not correspondent directly with the mechanical properties of cured composites manufactured on the base of the treated fabrics. Alkali- and organic treatments significantly improve the mechanical performance of natural fibres reinforced composites, but organic treatments (methanol, toluene diisocyanate) gives better improvement in mechanical properties in comparison with the alkali-treatments. The measurement methods applied in the study may be generally useful in the evaluation of the effect of chemical treatment of natural fibres on their wettability with the liquid matrix.

Powders of two molybdenum carbides (Mo₂C and MoC_1-x) and tungsten carbide (WC) were prepared by means of temperature programmed reaction (TPR) method. Mo₂C and MoC_1-x were synthesized by reacting MoO₃ with a preselected molar ratio of methane/hydrogen and carbon monoxide/hydrogen gas mixtures respectively. WC was prepared using tungsten oxide (WO₃) and a methane/hydrogen gas mixture. These carbides were ultrasonically dispersed in de-ionized water. Samples were characterized using room temperature x-ray diffraction and scanning microscopy. A kinetic diffusion model is also studied to determine diffusivities in solids where the diffusing species desorbs or reacts at the external surfaces, and where the diffusivity does not vary appreciably with concentrations. The method involves measuring the flux of the diffusive species into the solid under the influence of a temperature program.

This paper presents an experimental investigation of two incline solar water desalination (ISWD) systems. One design uses spray jets for spraying water onto the absorber plate, while the other uses a longitudinal slot for getting the inlet water on the absorber plate. The first ever ISWD system constructed and tested by Aybar et al (2005) used the longitudinal slot with a maximum daily production of 2.995 kg/m² day. The Aybar et al design produced 3.4 kg/m²-day while the new design produced 6.41 kg/m²-day for wick on absorber plate system day during the hottest months in Famagusta (July-August 2010). Also tested was the influence of porous media (wire mesh), wick on the absorber plate. The effect of number of spray jets used in the system on the daily productivity and efficiency of the systems were also investigated.

The aim of the work is to describe a capability of the active carbon CARBON L-2-4 (AC) and of the nanocarbon (NC) materials containing iron nanoparticles to continuously remove SO₂ from air. The carbon nanomaterials (NC) containing iron nanoparticles were synthesised using a chemical vapor deposition method - through catalytic decomposition of ethylene on nanocrystalline iron.

The process of SO₂ removal was carried out on dry and wet with water carbon catalyst (AC or NC) and was studied for inlet SO₂ concentration 0.3 vol.% in the presence of O₂, N₂ and H₂O, in the temperature range of 40-80°C.

Emulsion liquid membrane technique (ELM) was used for the extraction of phenol from synthetic and industrial effluents. In this study, the liquid membrane used for phenol removal was composed of kerosene as the solvent, Span-80 as the surfactant and Sodium hydroxide as an internal reagent. Statistical experimental design was applied for the optimization of process parameters for the removal of phenol by ELM. The effects of process parameters namely, Surfactant concentration, membrane or organic to internal phase ratio (M/I) and emulsion to an external phase ratio (E/E) on the removal of phenol were optimized using a response surface method. The optimum conditions for the extraction of phenol using Response surface methodology were: surfactant concentration - 4.1802%, M/I ratio: 0.9987(v/v), and E/E ratio: 0.4718 (v/v). Under the optimized condition the maximum phenol extraction was found to be 98.88% respectively.

The adsorption behavior of Pb(II) and Cd(II) ions in aqueous solutions on silica aerogels modified with amino propyl triethoxysilane was investigated as a function of pH, contact time, adsorbate concentration and adsorbent dose. It was found that maximum adsorption of Pb(II) and Cd(II) ions occurs at pH 6.0 and pH 8.0, respectively. The optimum contact time to obtain equilibrium adsorption with the modified silica aerogel was experimentally found to be around 48h. Adsorption isotherms clearly indicated that the adsorption behavior of metals ions on the modified silica aerogels is fitted well with both the Langmuir and Freundlich isotherms. The maximum adsorption capacities of Pb(II) and Cd(II) on modified silica aerogel were found to be 45.45mg/g and 35.71mg/g, respectively. The results indicated that silica aerogels modified with amino functional groups can be used as an efficient adsorbent in the removal of metal ions such as Pb(II) and Cd(II) from aqueous solutions.

Stimuli-responsive drug delivery system is a concept in which a drug is delivered at a suitable rate in response to stimuli. States of diseases may cause an alteration in some parameters of the body (e.g. in tumors) and the onset and offset of the drug delivery can be done by using this as a stimuli or a "trigger". Stimuli-responsive ("intellectual" or "sharp") resources and molecules show abrupt property changes in response to miniature changes in external stimuli such as pH, temperature etc. For regulated drug delivery, environmental stimuli such as pH and temperature, which undertake phase transition in polymer system, have been investigated. Thermally-responsive polymers can be tuned to a preferred temperature variety by copolymerization with a hydrophilic co-monomer or a hydrophobic co-monomer. Hydrophilic co-monomers increase the LCST while hydrophobic co-monomers decrease the LCST. The stimuli responsive polymer for regulated drug delivery can contain a polymer and copolymers having equilibrium of hydrophilic and hydrophobic groups. A number of these polymers have been investigated extensively and some success in drug delivery with them has been achieved, such as polymers and copolymers of N-isopropylacrylamide, PLGA, and PLA, HEMA etc. Thus this review is designed for stimuli pH and temperature responsive polymeric nanoparticles, which would be helpful to treat various cronic diseases such as cancer and others, for scientists in the field of the regulated drug delivery system.

This communication explores the feasibility of biodiesel production from a weed plant Argemone mexicana seed oil and an efficient catalyst crystalline manganese carbonate. To the best of the authors' knowledge, this is the first study making use of pure, crystalline, ash colored manganese carbonate as a heterogeneous catalyst for the production of methyl esters as fuel from Argemone mexicana seed oil. The optimum process conditions for the conversion of Argemone mexicana oil to its methyl ester by transesterification required 1% manganese carbonate as catalyst with alcohol to oil ratio 5:1 at 60°C to yield biodiesel of 99.99% purity. The methyl esters obtained were examined by Gas chromatography analysis.

This study aims to explore the efficiency of an agro waste material for the remediation of Pb(II) contaminated water. A factorial design approach is adopted to optimize removal efficiency and to study the interaction between effective variables. A face-centered Draper-Lin composite design predicted 100% removal efficiency at optimum variables; pH 8, initial concentration of Pb(II) ion 12mg/L, sorbent dose 200mg and agitation time 110 min. Regration coefficient (R² = 99.9%) of a plot of the predicted versus the observed values and p value (>0.05) confirms the applicability of the predicted model. Langmuir and Dubinin-Radushkevich (D-R) isotherm models were applicable to sorption data with the Langmuir sorption capacity of 21.61±0.78 mg/g. The energy of sorption was found to be 13.62±0.32 kJ/mol expected for ion-exchange or chemisorption nature of sorption process. Characterization of Grewia seed suggested a possible contribution of carboxyl and hydroxyl groups in the process of biosorption. The present study shows that Grewia seeds can be used effectively for the remediation of Pb(II) contaminated water.