Physicochemical Characterization of Interaction of Ibuprofen by Solid-State Milling with Aluminum Hydroxide

This present study is a preliminary exploration of the affinity between a carboxylic model drug ibuprofen and aluminum hydroxide. Ibuprofen was comilled with aluminum hydroxide in different weight ratios in the solid state and was characterized by scanning electron microscopy (SEM), X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and in vitro dissolution studies. XRD and SEM studies indicated complete interaction of ibuprofen with aluminum hydroxide and complete amorphization of aluminum hydroxide–ibuprofen complexed salt as well, on comilling with aluminum hydroxide at 1:2 ratio. FTIR data showed the disappearance of acid carbonyl peak with the appearance and the corresponding increase in absorbance of new signal at 1,682 cm^?1 in the 1:1 and 1:2 ibuprofen–aluminum hydroxide-comilled powder. The accompanied increase in the absorbance of carboxylate peak in the ibuprofen–aluminum hydroxide physical mixture, and 1:0.1, 1:0.5, 1:1, and 1:2 (IBA_pm, and IB₁A_0.1, IB₁A_0.5, IB₁A₁, and IB₁A₂, respectively) comilled powder indicated an acid–base reaction between ibuprofen and aluminum hydroxide. On storage at 40°C and 75% relative humidity (RH) for 10 weeks, XRD study showed the absence of reversion to the crystalline state and FTIR data revealed continued increase of new signal at 1,682 cm^?1 relative to carboxylic acid peak and no reappearance of carboxylic acid peak. In vitro dissolution studies revealed that the percent release of ibuprofen from the aluminum hydroxide-comilled powder is in the following order: IB₁A₂ < IB₁A₁ < ibuprofen crystal < ibuprofen milled alone < IB₁A_0.1 < IB₁A_0.5. Aluminum metal cation might have interacted to form a complex through the carboxyl and carbonyl groups of ibuprofen. Improved dissolution of drug associated with IB₁A_0.1 and IB₁A_0.5 is because of the absence of a new signal at 1,682 cm^?1 and improved amorphization of the drug to some extent. Dissolution of drug affected in IB₁A₂ and IB₁A₁ may be because of the insoluble stable complex formation.     

Sizing Cracks in Power Plant Components Using Array Based Ultrasonic Techniques

New techniques developed using the array transducer, to image and size the bottom-surface and near-through-wall crack-like defects in thick carbon steel components are discussed. Three studies are reported here including (a) Optimal beam steering angle for focused and unfocused inspection using phased array method for bottom-surface crack sizing. (b) A front wall correction algorithm for sizing of near-through-wall crack-like defects. (c) A small aperture technique for sizing of near-through-wall crack-like defects. A Finite Difference Time Domain (FDTD) based simulation was used to study and verify the experimental observations. The application of time domain scheme relative arrival time technique (RATT), to measure the size of the near-through wall crack-like defects for the leak before break (LBB) criterion, was also investigated and found to be insufficient. A conventional SAFT algorithm was used for improving the sizing using the small aperture technique.     

Biogas production enhancement by soya sludge amendment in cattle dung digesters

Biogas energy production from cattle dung is an economically feasible and eco-friendly in nature. But dependence only on cattle dung is a limiting factor. Rich nitrogen containing substrate addition to extra carbohydrate digester like cattle dung could improve the biogas production. Detailed performance of the digesters at different ratios of cattle dung and soya sludge has been discussed in this paper considering the cold countries climate. Soya sludge substrate not only has high nitrogen content of 4.0–4.8% but it also has high percentage of volatile solids content in the range of 97.8–98.8%. Soya sludge addition also improved the manurial value of the digested slurry and also improved the dewater-ability of the sludge. Results indicated an increment of 27.0% gas production at 25.0% amendment of soya sludge in non-homogenized cattle dung (NCD) digester. The amount of gas production increased to 46.4% in case of homogenized cattle dung (HCD) with respect to NCD feed at the same amendment.     

Reactive wetting of Sn–2.5Ag–0.5Cu solder on copper and silver coated copper substrates

In the present work, wetting characteristics and morphology of intermetallic compounds (IMCs) formed between Sn–2.5Ag–0.5Cu lead-free solder on copper (Cu) and silver (Ag) coated copper substrates were compared. It was found that, Ag coated Cu substrate improved the wettability of solder alloy. The average values of contact angles of solder alloy solidified on Ag coated Cu substrate were reduced to about 50 % as compared to contact angles obtained on Cu substrates. Flow restrictivity for spreading of solder on Ag coated Cu was found to be lower as compared to Cu substrate. The spreading of solder alloy on Ag coated Cu exhibited halo zone. Coarse needle shaped Cu₆Sn₅ IMCs were observed at the solder/Cu substrate interface whereas at the solder/Ag coated Cu interface Cu₆Sn₅ IMCs showed scallop morphology. The formation of Cu₃Sn IMC was observed for the spreading of solder alloy on both substrates. The solder/Ag coated Cu substrate interface exhibited more particulates of Ag₃Sn precipitates as compared to solder/Cu substrate interface. The improved wettability of solder alloy on Ag coated Cu substrate is due to the formation of scallop IMCs at the interface.     

Spreading Behavior and Evolution of IMCs During Reactive Wetting of SAC Solders on Smooth and Rough Copper Substrates

The effect of surface roughness of copper substrate on the reactive wetting of Sn-Ag-Cu solder alloys and morphology of intermetallic compounds (IMCs) was investigated. The spreading behavior of solder alloys on smooth and rough Cu substrates was categorized into capillary, diffusion/reaction, and contact angle stabilization zones. The increase in substrate surface roughness improved the wetting of solder alloys, being attributed to the presence of thick Cu₃Sn IMC at the interface. The morphology of IMCs transformed from long needle shaped to short protruded type with an increase in the substrate surface roughness for the Sn-0.3Ag-0.7Cu and Sn-3Ag-0.5Cu solder alloys. However, for the Sn-2.5Ag-0.5Cu solder alloy the needle-shaped IMCs transformed to the completely scallop type with increase in the substrate surface roughness. The effect of Ag content on wetting behavior was not significant.     

Electrochemical Pretreatment of Wastewater from Bulk Drug Manufacturing Industry

The present study involves the treatment of high strength Bulk Drug Industry Wastewater by electrochemical method. The treatability studies were carried out with four different electrodes made of mild steel, aluminum, carbon, and stainless steel. The treatment efficiencies for chemical oxygen demand (COD)/biochemical oxygen demand (BOD), color, and heavy metal removals were assessed at different electrolysis time. A comparative study for heavy metal removal between chemical precipitation using aluminum and electrocoagulation with aluminum electrode has shown electrocoagulation to be more effective. Carbon electrode has shown COD removal of 34.0% and high BOD5f/CODf ratio of 0.581 at 120-min exposure time. Among all electrodes, aluminum was found as the most efficient in removal of color, suspended solids, and heavy metals with the least energy consumption of 95.83?Wh?kg?1?CODr and anode efficiency of 5.76?kg?COD?A?1?m?2?h?1. After electrochemical treatment, certain increase in BOD/COD ratio attributed to increase in biodegradability of wastewater. The study reveals that the wastewater could be effectively pretreated by electrochemical method.     

Long‐term irreversible changes in a lake ecosystem affected by the Indian Ocean Tsunami

This study focused on ecosystem responses to the environmental perturbations caused by the 2004 Indian Ocean Tsunami in a small lake that was a freshwater body in 1996, prior to the tsunami. The physicochemical and biological characteristics of Kokilamedu Lake (KKM) revealed drastic changes, compared with pretsunami conditions. Monthly average observations on water quality indicated the electrical conductivity of the water increased steeply to 17.41 mS cm^?1 in 2009, from the lowest pretsunami value of 1.83 mS cm^?1 (range of 1.83–5.25 mS cm^?1). Simultaneously, the nitrate + nitrite (NO₃ + NO₂) values increased significantly from 0.49 μmol L^?1 in 1996 to 74.47 μmol L^?1 in 2006. Silicate (SiO₄‐Si) exhibited a dramatic increase in concentration, from an average of 64.87 μmol L^?1 in the pretsunami period to 309.71 μmol L^?1 the post‐tsunami period (2009–2010). Inorganic phosphate had increased to a maximum of 9.59 μmol L^?1 from a pretsunami maximum of 1.09 μmol L^?1. The chlorophyll‐α concentrations did not respond to the increased nutrient stoichiometry of the lake. There was a decreased chlorophyll‐α concentration under post‐tsunami conditions. The recent infilling of the lake with sediment during the tsunami, associated with wind‐driven resuspension reduced the light penetration. There was a significant improvement in dissolved oxygen concentrations (2006–2010 average of 8.27 mg L^?1) in the lake, however, compared with the pretsunami values (1994–1995 average of 5.94 mg L^?1). The algal component is now dominated by blue‐green algae, while green algae had dominated in the pretsunami period. Pre‐ and post‐tsunami observations from a control site did not exhibit such dramatic shifts from the 1995 and 1996 conditions, whereas a shift was apparent in the case of KKM. Certain marine fishes have adapted to this altered ecosystem. These marine species encountered (Elops machnata, Cociella punctata, Sphyraena jello, Platycephalus indicus, Glossogobius giuris) might have been recruited during the intrusion of the tsunami waves.