Rheology and fuel properties of slurries of char and bio-oil derived from slow pyrolysis of cassava pulp residue and palm shell

Three bio-oil samples, namely, raw bio-oil from pyrolysis of cassava pulp residue (CPR), separated oil phase and aqueous phase of bio-oil from pyrolysis of palm shell (PS), were used as suspending media for preparing slurries of bio-oil and the co-product char. Rheologies of all tested slurries exhibited pseudoplasticity with yield stress and the degree of this non-Newtonian behavior depended on such parameters as slurry type, solid concentration, particle size and slurry temperature. Overall, char/bio-oil slurries gave better fuel properties including higher pH and reasonably high calorific value (18?C32 MJ/kg) as compared to their bio-oil properties. Combustion of char/bio-oil slurries occurred in the temperature range similar to their solid char combustion and without ignition delay.     

Effect of Heat‐Moisture Treatment on Structural and Thermal Properties of Rice Starches Differing in Amylose Content

Starches from glutinous rice (1.4% amylose), Jasmine rice (15.0% amylose) and Chiang rice (20.2% amylose) were exposed to heat‐moisture treatment (HMT) at 100 °C for 16 h and at different moisture levels (18, 21, 24 and 27%). The effect of heat‐moisture treatment on structural and thermal properties of these three rice starches was investigated. The HMT did not change the size, shape and surface characteristics of rice starch granules. The A‐type crystalline pattern of rice starches remained unchanged after HMT. The relative crystallinity (RC) and the ratio of short‐range molecular order to amorphous (RSA) of heat‐moisture treated glutinous and Jasmine rice starches decreased with increasing moisture level of the treatments. In contrast, the RC of the treated Chiang rice starch remained practically unchanged. A peak of crystalline V‐amylose‐lipid complexes was clearly presented in all treated Chiang rice starches. The peak became progressively stronger with increasing moisture level of the treatment. Differential scanning calorimetry (DSC) of all treated rice starches showed a shift of the gelatinization temperature to higher values. Increasing moisture level of the treatments increased the onset gelatinization temperature (T_o) but decreased the gelatinization enthalpy (ΔH) of rice starches. A broad gelatinization temperature range (T_c‐T_o) with a biphasic endotherm was found for all treated Chiang rice starches and Jasmine rice starch after HMT₂₇ (HMT at 27% moisture level). Additionally the (T_c‐T_o) of treated Chiang rice starches increased linearly with increasing moisture level of the treatments.     

Nanosized GdVO_4 powders synthesized by sol-gel method using different carboxylic acids

Nanosized GdVO_4 powders were synthesized via a sol-gel method using different carboxylic acids as chelating agent, followed by calcination at 600 ℃ for 3 h.The effect of different carboxylic acids such as citric acid,malic acid, and tartaric acid on the characteristics of the nanosized GdVO_4 powders was investigated. The GdVO_4 powder was also synthesized without carboxylic acid for comparison. The thermal decomposition process of the carboxylate precursors was investigated by thermogravimetric differential thermal analysis(TG-DTA). X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR),field emission scanning electron microscope(FESEM),transmission electron microscope(TEM), and surface area measurement data were used to confirm the formation of nanocrystalline GdV04 powders. It is found that the synthesis using the carboxylic acid with higher heat of combustion results in the powder with larger crystallite size. The difference in the steric effect of the acids used,which was evaluated by a computational method, also affects the degree of agglomeration of the synthesized powders.     

Activities and perceptions of pharmacists providing tobacco control services in community pharmacy in Thailand.

Community pharmacists' involvement in tobacco control and their perceived role and barriers were assessed. In part I, a self-administered questionnaire was mailed to 164 community pharmacists who applied for community pharmacy accreditation from the Thai Pharmacy Council in 2003. In part II, an in-depth interview was conducted among 13 community pharmacists who participated in the 1-day smoking cessation services training. Main outcome measures were tobacco control-related activities, perceived tobacco control role, and perceived barriers. The questionnaire response rate was 51% (83/164 pharmacists), with half of the respondents (42/83, 51%) reporting active tobacco control activities. Of these pharmacists, seven (7/42, 17%) reported participating in public or policy advocacy by campaigning against smoking in the community. Thirty-four (34/42, 81%) and thirty-six (36/42, 86%) reported engaging in activities in their own pharmacies by providing educational materials and smoking cessation services, respectively. Even though the perceived roles in tobacco control of these pharmacists were high, they also reported several barriers, especially in five categories: lack of client demand, lack of educational materials, lack of smoking cessation products, lack of knowledge and skill, and lack of follow-up visits. On the other hand, lack of time and lack of reimbursement were not indicated as important barriers. Data from in-depth interviews confirmed these findings. This study revealed that Thai community pharmacists were engaged in various levels of tobacco control-related activities. Most of them perceived the significance of tobacco control activities. However, several barriers were also reported and need to be addressed further.     

Structural analysis of lead fullerene-based inhibitor bound to human immunodeficiency virus type 1 protease in solution from molecular dynamics simulations

Molecular dynamics (MD) simulations of the HIV-1 protease (HIVP) complexed with lead fullerene-based inhibitor (diphenyl C60 alcohol) in the three protonated states, unprotonated (Un-), monoprotonated (Mono-), and diprotonated (Di-) states at Asp25 and Asp25' were performed. As the X-ray structure of the investigated complex is not available, it was built up starting with the X-ray crystallographic structure of the HIVP complexed with non-peptide inhibitor (PDB code: 1AID) and that of the diphenyl C60 alcohol optimized using the integrated ONIOM molecular orbital calculations. The inhibitor was, then, introduced into the enzyme pocket using a molecular docking method. Change of the HIVP binding cavity for all three states were evaluated in terms of distance between the two catalytic residues, Asp25 and Asp25' as well as those between the catalytic residues and the flap regions. The torsional angles formed by the O-C-C-O of the two carboxyl groups of the catalytic dyad show the non-planar configuration with the most frequency at about -45 degrees for the Un-, 35 degrees and -95 degrees for the Mono- and 60 degrees for the Di-systems. At equilibrium, different orientations of the fullerene-based inhibitor in the three protonation states were observed. For the Di-state, the OH group of the inhibitor stably forms hydrogen bonds with the two aspartic residues. It turns to the flap region to form hydrogen bonding to the backbone N of Ile50' for the Un-state. In contrast, the OH group turns to locate between the catalytic and the flap region for the Mono-states. Beside the molecular orientation, the rotation of the OH group of the inhibitor in the Un-state was also detected. In terms of solvation, the carboxylate oxygens of the aspartic residues in the Un- and Mono-states were solvated by one to three water molecules while the OH group in these two states was coordinated by one water molecule. This is in contrast to the Di-state in which no water molecule is available in the radius of 5-6A around the oxygen atoms of the carboxylate groups of enzyme and of the OH group of the inhibitor. The simulated results lead to the conclusion that the active site of the HIVP complexed with the diphenyl C60 alcohol is the diprotonation states on Asp25 and Asp25'.     

Study of Asphaltene Precipitation Using Refractive Index Measurement

The measurements of the refractive index of crude oils were utilized in this work to enhance the understanding of the behavior of asphaltenes in crude oil, specifically, their tendency to precipitate from crude oil. The onset of asphaltene precipitation was measured in eight crude oil samples, which were titrated with either heptane or pentane in order to induce precipitation of the asphaltenes. The refractive index of each sample was measured to find its relationship to asphaltene precipitation. The assumption that refractive index of a mixture is a linear combination of the refractive indexes of the individual components was verified. It was also found that mixtures of heptane or pentane and crude oil also followed this same behavior. However, as asphaltenes began to precipitate from the solution, the refractive index no longer followed this linear mixing rule. Careful analysis of the refractive index data for each of the crude oil samples revealed many interesting relationships between the refractive index data and the content of the different polar asphaltene fractions present. The refractive index of asphaltenes was predicted from the refractive index data of crude oils. The results suggest the possibility predicting the properties and characteristics of the asphaltenes contained in a crude oil simply by measuring the refractive index.     

Effect of nitrate on the performance of single chamber air cathode microbial fuel cells

The effect of nitrate on the performance of a single chamber air cathode MFC system and the denitrification activity in the system were investigated. The maximum voltage output was not affected by 8.0mM nitrate in the medium solution at higher external resistance (270-1000Omega), but affected at lower resistance (150Omega) possibly due to the low organic carbon availability. The Coulombic efficiency was greatly affected by the nitrate concentration possibly due to the competition between the electricity generation and denitrification processes. Over 84-90% of nitrate (0.8-8.0mM) was removed from the single chamber MFCs in less than 8h in the first batch. After 4-month operation, over 85% of nitrate (8.0mM) was removed in 1h after the MFC was continuously fed with a medium solution containing nitrate. Only a small amount of nitrite (<0.01mM) was detected during the denitrification process. The similar denitrification activity observed at different external resistances (1000 and 270Omega) and open circuit mode indicates that the denitrification was not significantly affected by the electricity generation process. No electricity was generated when the MFC fed with 8.0mM nitrate was moved to a glove box (no oxygen), indicating that the bacteria on the cathode did not involve in accepting electrons from the circuit to reduce the nitrate. Denaturing Gradient Gel Electrophoresis (DGGE) profiles demonstrate a similar bacterial community composition on the electrodes and in the solution but with different dominant species.     

Integrated treatment scheme for rubber thread wastewater: sulfide precipitation and biological processes

In this study, acidic latex wastewater containing high average zinc and acetic contents of 816mgL(-1) and 20,862mgCODL(-1), respectively, was treated successfully by a series of chemical and biological processes without any addition of acid or base for pH adjustment. Total dissolved solids of the treated effluent increased by only 1.1-fold on average for sulfide precipitation as compared to 2.8-fold for the hydroxide strategy. The oxidation-reduction potential (ORP) value of 0mV was used successfully as an indicator for optimum sulfide addition which consistently provided an appreciable reduction in effluent concentrations to less than 1 and 2mgL(-1) for zinc and residual sulfide, respectively. The anaerobic filter was very stable in handling the chemically treated wastewater up to the organic loading rate of 11.8gCODL(-1)day(-1) with an average efficiency of 92%. Methane production and biomass yield were 0.32L(gCOD(removed))(-1) and 0.014gVSS (gCOD(removed))(-1), respectively. For the activated sludge process, the optimum sludge age and hydraulic retention time were 30 and 0.8 days, respectively, which are equivalent to the organic loading rates of 2.50gCODL(-1)day(-1) or 2.13gBODL(-1)day(-1). Under these optimum conditions, average removal efficiencies for COD and BOD were 96.6 and 99.4%. Average soluble COD, BOD and suspended solids in the effluent were 71, 11 and 38mgL(-1), respectively. This integrated treatment scheme was proven to be an effective approach for highly polluted and toxic rubber thread wastewater.