Increased productivity of Clostridium acetobutylicum fermentation of acetone, butanol, and ethanol by pervaporation through supported ionic liquid membrane

Pervaporation proved to be one of the best methods to remove solvents out of a solvent producing Clostridium acetobutylicum culture. By using an ionic liquid (IL)-polydimethylsiloxane (PDMS) ultrafiltration membrane (pore size 60 nm), we could guarantee high stability and selectivity during all measurements carried out at 37C. Overall solvent productivity of fermentation connected with continuous product removal by pervaporation was 2.34 g l(-1) h(-1). The supported ionic liquid membrane (SILM) was impregnated with 15 wt% of a novel ionic liquid (tetrapropylammonium tetracyano-borate) and 85 wt% of polydimethylsiloxane. Pervaporation, accomplished with the optimized SILM, led to stable and efficient removal of the solvents butan-1-ol and acetone out of a C. acetobutylicum culture. By pervaporation through SILM, we removed more butan-1-ol than C. acetobutylicum was able to produce. Therefore, we added an extra dose of butan-1-ol to run fermentation on limiting values where the bacteria would still be able to survive its lethal concentration (15.82 g/l). After pervaporation was switched off, the bacteria died from high concentration of butan-1-ol, which they produced

Correlation between the Surface Energetics of Reinforcement and Mechanical Properties of Carbon/Carbon Composites

Surface energetics of reinforcement is one of the most important properties in case of adhesion of reinforcement in composites . For this study, PAN fibres were stabilized isothermally with three different timings (viz. 0, 1, 2 h) and eventually prepared fibres having different surface energetics were evaluated by DCA 322. Composites were made by using these stabilized fibres (designated as OP, 1 P, and 2P) with coal tar pitch as matrix precursor using match mould die technique. Green composites were carbonized upto 1000°C, then impregnated and heat treated to 1500, 2000 and 2600°C. Green composites as well as heat treated composites were studied for their mechanical properties . Microstructure as well as interfacial studies were carried out using optical microscope. Optical microscopic examination of composite samples show that Ill treated fibres offer much better adhesion with matrix precursor and the matrix also exhibits an obvious increase in the anisotropic domain size in case of 2P composites . Density of stabilized fibres and also of green composites has been found to increase with stabilization time. Flexural strength of green composites prepared with 0 and 2h treated fibres decreases ( 123 MPa to 60 MPa). However, as a result of better bonding between fibre and matrix , in case of IP composites , strength is always high except in green stage . An attempt has been made to correlate the surface energetics of fibre with mechanical properties as well as matrix microstructure of carbon /carbon composites

The Design and Implementation of a Wireless Video Surveillance System.

Internet-enabled cameras pervade daily life, generating a huge amount of data, but most of the video they generate is transmitted over wires and analyzed offline with a human in the loop. The ubiquity of cameras limits the amount of video that can be sent to the cloud, especially on wireless networks where capacity is at a premium. In this paper, we present Vigil, a real-time distributed wireless surveillance system that leverages edge computing to support real-time tracking and surveillance in enterprise campuses, retail stores, and across smart cities. Vigil intelligently partitions video processing between edge computing nodes co-located with cameras and the cloud to save wireless capacity, which can then be dedicated to Wi-Fi hotspots, offsetting their cost. Novel video frame prioritization and traffic scheduling algorithms further optimize Vigil's bandwidth utilization. We have deployed Vigil across three sites in both whitespace and Wi-Fi networks. Depending on the level of activity in the scene, experimental results show that Vigil allows a video surveillance system to support a geographical area of coverage between five and 200 times greater than an approach that simply streams video over the wireless network. For a fixed region of coverage and bandwidth, Vigil outperforms the default equal throughput allocation strategy of Wi-Fi by delivering up to 25% more objects relevant to a user's query

Digestibility and metabolizable energy of selected tropical feedstuffs estimated by in vitro and prediction equations

In vivo determination of digestible organic matter (dOM) and metabolisable energy (ME) concentrations of feeds is laborious and expensive, whereas analysis of their nutrient contents is routinely performed. Prediction equations based on the chemical composition of feeds can be a compromise. This study compared dOM and ME estimates of tropical feeds derived from selected equations (Yan and Agnew, 2004; Stergiadis et al., 2015a; Stergiadis et al., 2015b; AFRC, 1993) with those determined by the in vitro gas production method (Menke and Steingass, 1988). Samples of supplement feedstuffs (n = 12) and the herbaceous and ligneous vegetation on native pastures (n = 12) were collected in Lower Nyando, Kenya, over two seasons of one year. Samples were analysed for dry matter (DM; in % of fresh matter), crude ash, crude protein, ether extract, neutral and acid detergent fiber (NDF, ADF) (all in % of DM). Gross energy was determined by calorimetry. Nutrient concentrations varied across all samples with 8.5 – 87.9% DM, 5.2 – 16.8% crude ash, 36.7 – 74.1% NDF, 25.5 – 39.4% ADF, 3.2 – 14.2% crude protein, and 0.6 – 4.5% ether extract. The gross energy, in vitro dOM, and ME concentrations were 14.5 – 18.8 MJ/kg DM, 26.3 – 54.5%, and 3.8 – 8.4 MJ/kg DM, respectively. Compared with the in vitro method, all nutrient-based equations overestimated dOM (P 0.5). Nutrient-based equations do not sufficiently account for differences in nutrient availability, an aspect better simulated in vitro. Further development and/or validation of nutrient-based equations might be needed to more accurately predict dOM and ME of tropical feeds. AFRC. 1993. Wallingford: CAB International. Stergiadis et al. 2015a. J Dairy Sci, 98(5), 3257–3273 Stergiadis et al 2015b. Brit J Nutr, 113(10), 1571–1584. Yan and Agnew. 2004. J Anim Sci., 82, 1367–1379