Synthesis of long chaina,B-alkynoic anda,B-alkynoic acids viaB-keto esters

A general method for the synthesis of long chain α,β-alkynoic acids from β-keto esters is described. The synthesis involves conversion of the β-keto ester to the corresponding pyrazolone, then halogenation and treatment of the resultant 4,4-dihalo product with dilute aqueous alkali to form the α,β-alkynoic acids. Specifically, 2-octynoic, 2-nonynoic and 2-decadecynoic acids were prepared as representative examples. If the β-keto ester has an alkyl group at the α-position, the final product is a mixture ofcis andtrans α-substituted-α,β-unsaturated alkenoic acids, which may be separated by gas-liquid chromatography. Pertinent IR and proton magnetic resonance data are used in characterizing the stereochemistry of products and a possible mechanism for the product forming reactions is presented. Presented in part at the AOCS Meeting, October 1966.     

Chemical reactions involved in the catalytic hydrogenation of oils. II. Identification of some volatile by-products

Gas chromatography of the volatile by-products produced during the catalytic hydrogenation of an autoxidized soybean oil with a peroxide number of 11.2 meq/kg yielded approx 41 peaks. Twenty-one of the gas chromatographic fractions were collected and rechromatographed, and their chemical identity studied with micro-iR and mass spectrophotometry. These volatile by-products, according to peak area of gas chromatogram, showed a predominance of hydrocarbons and alcohols. The fractions which have been identified aren-octane,n-nonane,n-decane,n-heptadecane,n-hexanol,n-heptanol,n-decanol,n-hexanal,n-decanal and 3-nonanone. Among the gas chromatographic fractions collected,n-decanol has an odor most reminiscent of that of catalytic hydrogenation. Supported by a PHS research grant HE-06411 from the National Heart Institute, Public Health Service. Paper of the Journal Series, N.J. Agricultural Exper. Sta., Rutgers, The State University of New Jersey, Dept. of Food Science, New Brunswick.     

Efficient organic tandem cell combining a solid state dye-sensitized and a vacuum deposited bulk heterojunction solar cell

In this letter, we report on an efficient organic tandem solar cell combining a solid state dye-sensitized with a ZnPc/C₆₀-based, vacuum deposited bulk heterojunction solar cell. Due to an effective serial connection of both subcells and to the complementary absorption of the dyes used, a power conversion efficiency of η_p=(6.0±0.1)% was achieved under simulated AM 1.5 illumination. The device parameters are , and FF=(54±1)%.     

The impact of wave energy farms in the shoreline wave climate: Portuguese pilot zone case study using Pelamis energy wave devices

This paper describes the study of the impact of energy absorption by wave farms on the nearshore wave climate and, in special, the influence of the incident wave conditions and the number and position of the wave farms, on the nearshore wave characteristics is studied and discussed. The study was applied to the maritime zone at the West coast off Portugal, namely in front of São Pedro de Moel, where it is foreseen the deployment of offshore wave energy prototypes and farms between the 30 m and 90 m bathymetric lines, with an area of 320 Km². In this study the REFDIF model was adapted in order to model the energy extraction by wave farms. Three different sinusoidal incident wave conditions were considered. Five different wave farm configurations, varying the position of the wave farm, its number and the width of the navigation channels at each wave farm were analysed. The results for each configuration in terms of the change of the wave characteristics (wave height and wave direction) at the nearshore are presented, compared and discussed for three representative wave conditions.     

Ecological efficiency and thermoeconomic analysis of a cogeneration system at a hospital

This work aims with an approach for cogeneration plants evaluation based on thermoeconomic functional diagram analysis. The second law of thermodynamics is used to develop a methodology to analyse cogeneration systems, based on exergoeconomics evaluation. The thermoeconomic optimisation method developed is applied to allow a better configuration of the cogeneration plant associated to a university hospital. Also ecological efficiency is evaluated. The method was efficient and contributes for thermoeconomics modelling and analysis and can be applied to any sort of thermal system, especially those with combined heat and power in thermal parity.     

Determination of ecological efficiency in internal combustion engines: The use of biodiesel

This paper evaluates and quantifies the environmental impact from the use of some renewable fuels and fossils fuels in internal combustion engines. The following fuels are evaluated: gasoline blended with anhydrous ethyl alcohol (anhydrous ethanol), conventional diesel fuel, biodiesel in pure form and blended with diesel fuel, and natural gas. For the case of biodiesel, its complete life cycle and the closed carbon cycle (photosynthesis) were considered. The ecological efficiency concept depends on the environmental impact caused by CO₂, SO₂, NO_x and particulate material (PM) emissions. The exhaust gases from internal combustion engines, in the case of the gasoline (blended with alcohol), biodiesel and biodiesel blended with conventional diesel, are the less polluting; on the other hand, the most polluting are those related to conventional diesel. They can cause serious problems to the environment because of their dangerous components for the human, animal and vegetable life. The resultant pollution of each one of the mentioned fuels are analyzed, considering separately CO₂, SO₂, NO_x and particulate material (PM) emissions. As conclusion, it is possible to calculate an environmental factor that represents, qualitatively and quantitative, the emissions in internal combustion engines that are mostly used in urban transport. Biodiesel in pure form (B100) and blended with conventional diesel as fuel for engines pollute less than conventional diesel fuel. The ecological efficiency for pure biodiesel (B100) is 86.75%; for biodiesel blended with conventional diesel fuel (B20, 20% biodiesel and 80% diesel), it is 78.79%. Finally, the ecological efficiency for conventional diesel, when used in engines, is 77.34%; for gasoline, it is 82.52%, and for natural gas, it is 91.95%. All these figures considered a thermal efficiency of 30% for the internal combustion engine.     

Effect of nanovesicle-encapsulated nisin on growth of Listeria monocytogenes in milk

Commercial nisin was encapsulated in nanovesicles (mean diameter 140 nm) prepared from partially purified soy lecithin. Nisin-loaded liposomes and unencapsulated (free) nisin were initially tested in BHI medium and skim milk inoculated with Listeria monocytogenes and incubated for 48 h at 30 °C. At such abuse temperature conditions, free nisin showed better inhibitory than the liposomal counterparts. Subsequently, the effect of encapsulated or free nisin was evaluated in combination with refrigeration (7 ± 1 °C) in both whole (3.25% fat) and skim (0% fat) milk for up to 14 day. A decrease of 3–4 log cycles in L. monocytogenes counts was observed for free and encapsulated nisin at 0.5 mg/ml concentration. Liposome encapsulation of antimicrobial peptides may be important to overcome stability issues and interaction with food components. The utilization of nanovesicle-encapsulated nisin in combination with low temperatures appeared to be effective to control L. monocytogenes in milk, emphasizing the importance of hurdle technology to assure food safety.