Continuous and efficient removal of THMs from river water using MF membrane combined with high dose of PAC

A combination of microfiltration (MF) membrane with a high concentration (40 g/L of the reactor) of powdered activated carbon (PAC) efficiently and continuously removed trihalomethanes (THMs) and total organic carbon (TOC) from river water for a period of two months. Without PAC, the membrane reactor was able to remove less than 18% of THMs and less than 5% of TOC; with PAC, 65 to 95% of THMs and TOC were removed. Even though the THMs concentration in the influent was steadily increasing (reaching 50 μg/L), THMs concentration in the effluents from the reactors with PAC were consistently below 15 μg/L. While the MF membranes alone could not remove organics, PAC and microbial activity in the biofilm deposited on the PAC particles assured long term and continuous removal of THMs. No additional PAC was added into or removed from the reactors during the filtration period. Operational parameters such as the backwashing of the membrane, interval of the filtration cycle and biological pretreatment of the river water had a small effect on the extent of THMs removal, but they increased the filtration time prior to membrane cleaning and improved the overall performance of the reactors.     

A disaggregate model for quantifying the safety effects of winter road maintenance activities at an operational level

This research presents a disaggregated modeling approach for investigating the link between winter road collision occurrence, weather, road surface conditions, traffic exposure, temporal trends and site-specific effects. This approach is unique as it allows for quantification of the safety effects of different winter road maintenance activities at an operational level. Different collision frequency models are calibrated using hourly data collected from 31 different highway routes across Ontario, Canada. It is found that factors such as visibility, precipitation intensity, air temperature, wind speed, exposure, month of the winter season, and storm hour have statistically significant effects on winter road safety. Most importantly, road surface conditions are identified as one of the major contributing factors, representing the first contribution showing the empirical relationship between safety and road surface conditions at such a disaggregate level. The applicability of the modeling framework is demonstrated using several examples, such as quantification of the benefits of alternative maintenance operations and evaluation of the effects of different service standards using safety as a performance measure.     

Antioxidant Activity of Sesame (Sesamum indicum L.) Cake Extract for the Stabilization of Olein Based Butter

This study investigated the effect of ethanolic sesame cake extract on oxidative stabilization of olein based butter. Fractionation of cream was performed by the dry fractionation technique at 10 °C, ethanolic sesame cake extract (SCE) was incorporated into olein butter at three different concentrations; 50, 100, 150 ppm (T₁, T₂, T₃) and compared with a control. The total phenolic content of SCE was 1.72 (mg gallic acid equivalent g^?1 dry weight). The HPLC characterization of ethanolic sesame cake revealed the presence of antioxidant substances viz. sesamol, sesamin and sesamolin in higher extents. The DPPH free radical scavenging activity of SCE was 83 % as compared to 64 and 75 % in BHA and BHT. Fractionation of milk fat at 10 °C significantly (p < 0.05) influenced the fatty acid profile of olein and stearin fractions from the parent milk fat. Concentration of oleic acid and linoleic acid in olein fraction was 29.62 and 33.46 % greater than the parent milk fat. The loss of C18:1 in 90 days stored control and T₃ was 24.37 and 3.58 %, respectively, 58 % C18:2 was broken down into oxidation products over 8.55 % loss in T₃. The peroxide value of control, T₁, T₂, BHT and T₃ in the Schaal oven test was 8.59, 8.12, 5.34, 4.52 and 2.49 (mequiv O₂/kg). The peroxide value and anisidine value of 3 months stored control and T₃ were 1.21, 0.42 (mequiv O₂/kg) and 27.25, 13.25, respectively. The concentration of conjugated dienes in T₃ was substantially less than the control. The induction period of T₃ was considerably higher than BHT with no difference in sensory characteristics (p > 0.05). Ethanolic SCE can be used for the long‐term preservation of olein butter, with acceptable sensory characteristics.     

Ferric nitrilotriacetate promotes N-diethylnitrosamine-induced renal tumorigenesis in the rat: implications for the involvement of oxidative stress

Ferric nitrilotriacetate (Fe-NTA) is a known complete renal carcinogen. In this study we show that Fe-NTA is a potent inducer of renal ornithine decarboxylase (ODC) activity and DNA synthesis and promoter of N-diethylnitrosamine (DEN)-induced renal tumorigenesis in rat. Fe-NTA induced renal ODC activity several fold as compared with saline-treated rats. Renal DNA synthesis, measured as [3H]thymidine incorporation into DNA, was increased after Fe-NTA treatment. Similar to other known tumor promoters, Fe-NTA also depleted the antioxidant armory of the tissue. It depleted glutathione (GSH) levels to approximately 55% of saline-treated controls. It also led to a dose-dependent decrease in the activities of glutathione reductase and glutathione S-transferase. Similarly, activities of catalase, glutathione peroxidase and glucose 6-phosphate dehydrogenase decreased significantly (45-65%). In contrast, gamma-glutamyl transpeptidase activity showed an increase. The maximum changes in activities of these enzymes could be observed at 12 h following Fe-NTA treatment. In addition, Fe-NTA augmented renal microsomal lipid peroxidation >150% over saline-treated controls, which was concomitant with the alterations in GSH metabolizing enzymes and depletion of the antioxidant armory. These effects were alleviated in rats which received a pretreatment with an antioxidant, BHA or BHT. Fe-NTA promoted DEN-induced renal tumorigenesis. In saline alone- and DEN alone-treated animals no tumors could be recorded, whereas in Fe-NTA alone-treated animals 17% tumor incidence was observed. However, in DEN-initiated and Fe-NTA-promoted animals tumor incidence increased to 71%. Our results show that Fe-NTA induces oxidative stress in the kidney and decreases antioxidant defenses, as indicated by the fall in GSH level and in the activities of glutathione peroxidase and catalase. Concomitantly, Fe-NTA increases ODC activity and DNA synthesis, which may be compensatory changes following oxidative injury to renal cells in addition to providing a strong stimulus for renal tumor promotion. Thus oxidative stress and impaired antioxidant defenses induced by Fe-NTA in the kidney may contribute to the observed nephrotoxicity and carcinogenicity.     

Fabrication of Mn–Co Spinel Coatings on Crofer 22 APU Stainless Steel by Electrophoretic Deposition for Interconnect Applications in Solid Oxide Fuel Cells

This study investigates the microstructure, oxidation kinetics, and electrical behavior of Mn–Co spinel coating for interconnect applications in solid oxide fuel cells. A relatively dense, uniform, and well‐adherent Mn–Co (Mn_1.5Co_1.5O₄) spinel coating with good oxidation resistance and stable conductivity was successfully prepared on the surface of Crofer 22 APU stainless steel using electrophoretic deposition followed by sintering at 1150°C. During further thermal treatment at 800°C, the chromium oxide (Cr₂O₃) sublayer formed at the substrate/coating interface during sintering showed a very slow growth, and no chromium penetration was detected in the Mn–Co coating. The oxidation kinetics of the Mn–Co‐coated substrate obeyed the parabolic law with the a parabolic rate constant k_p of 5.20 × 10^?15 g²/cm⁴/s, which was 1–2 orders of magnitude lower than that of the uncoated Crofer 22 APU stainless steel substrate. For oxidation (at 800°C) times ≥50 h, the area‐specific resistance of the Mn–Co‐coated Crofer 22 APU substrate became ~17 mΩ·cm² and was almost constant after further oxidation.     

Cadmium Incorporated Oil Based Bioactive Polymers: Synthesis, Characterization and Physico-chemical Studies

Zinc containing edible oil (coconut oil) based polyesteramide resins were synthesized by condensation polymerization between N,N′-bis (2-hydroxyethyl) coconut oil fatty amide (HECA), Zn (OH)₂ and citric acid/tartaric acid. The structural studies were carried out by FT-IR, ¹H-NMR and ¹³C-NMR spectroscopic techniques. Standard laboratory methods were used to study the physiochemical characteristics like acid value, hydroxyl value, saponification value, iodine value, specific gravity, and viscosity. The thermal behaviour of the polymers was analyzed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Both polymers were examined for antifungal and antibacterial properties and the results were compared with a standard drug. In the case of fungi, the growth curve (turbidometric measurement) was performed using a conventional spectrophotometer for the tartaric polymer, which showed higher biological activity against one of the Candida species.     

Electrochemical investigations of antioxidant interactions with radical anion and dianion of 1,3-dinitrobenzene

Interactions of five antioxidants (AO), quercetin (Q), morin (M), rutin (R), ascorbic acid (AA) and β-carotene (β-C) with anion radical and dianion of 1,3-dinitrobenzene (1,3-DNB) in two aprotic solvents – dimethyl formamide (DMF) and dimethyl sulfoxide (DMSO) – have been studied by cyclic voltammetry using glassy carbon electrode. Electrochemical parameters – peak potential (E_p), half-wave potential (E_1/2), and peak current (i_p) – for the reduction of 1,3-DNB before and after the addition of various concentrations of antioxidants, were evaluated. A gradual decrease in the oxidation peak current and finally irreversibility in 1,3-DNB radical anion and dianion systems upon the addition of antioxidant, reveals their interactions. The homogeneous bi-molecular rate constant (k₂) was determined from electrochemical data. In comparison to all other antioxidants used, enhanced homogeneous second order rate constant for the interaction of morin with 1,3-DNB anion radical and dianion, was observed. This aspect is attributable to protonation initiated by hydrogen bonding and greater acidic nature of morin.     

The effect of substrate position on the microstructure and mechanical properties of SiC coatings on carbon/carbon composites

In this work, silicon carbide (SiC) coatings were produced on carbon/carbon composites using a chemical vapour deposition (CVD) method. During deposition, the temperature was fixed at 1200 °C and the coatings were produced by placing substrates at three different positions (340, 380 and 420 mm from the inlet) in the CVD reactor. The effect of substrate position on the microstructure and mechanical properties of the SiC coatings were experimentally investigated. The phase composition, surface morphology, defects and microstructure were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman Spectroscopy. The hardness and Young's modulus were measured using a nano-indentation method while fracture toughness was evaluated by micro-indentation. It was found that the deposition rate decreased linearly as substrate position moved far from the reactor inlet. In all coatings, only β-SiC phase was observed with a high density of stacking faults. It was found that the substrate position in the CVD reactor has a significant effect on the microstructure, grain size and crystallinity of the coating. At 340 and 420 mm substrate positions, a well-developed faceted microstructure with high crystallinity was observed while at 380 mm substrate position, the coating having lenticular-like fine grains with low crystallinity was obtained. The hardness values obtained from the top surface of the coatings are found to be higher than those from the cross-section, although the Young's modulus data (measured from the top surface and cross-section) were observed to be similar. At 380 mm substrate position, hardness, Young's modulus and fracture toughness were found to be the lowest compared to that of the coatings produced at 340 and 420 mm substrate positions. It is concluded that the SiC coatings with better mechanical properties can be produced by adjusting the substrate position in the CVD reactor.