Enantioselective Esterification Of (±)-Menthol With Butyric Anhydride By Chemically Modified Candida Rugosa Lipase

Commercial lipase from Candida rugosa was chemically modified with the aim to improve its catalytic properties in organic solvents. The chemical modifiers, aldehydes and monomethoxy polyethylene glycols, were covalently linked to the lysine residues at the surface of the enzyme. Enzymatic enantioselective esterification of racemic menthol in organic solvents using butyric anhydride as acylating agent was performed with the chemically modified lipases. Different degrees of modification, organic solvents, reaction temperatures and water activity were examined for the influence on the percent yield and enantioselective formation of (-)-menthyl butyrate. The percent yield increased as the degree of modification increased but decreased slightly for the highest degree of modification. Organic solvents with log P values above 2.5 gave higher yield, however high enantioselectivity was obtained in all the organic solvents tested. The enantioselectivity towards (-)-menthol decreased considerably as the reaction temperature was increased. Enzyme derivatives exhibited better activity and enantioselectivity at high aw. The alkylated lipases showed higher thermal, solven

Combustor liner support assembly

A support assembly for a gas turbine engine combustor includes an annular frame having a plurality of circumferentially spaced apart tenons, and an annular combustor liner disposed coaxially with the frame and including a plurality of circumferentially spaced apart tenons circumferentially adjoining respective ones of the frame tenons for radially and tangentially supporting the liner to the frame while allowing unrestrained differential thermal radial movement therebetween

Low NO.sub.x combustor

A combustor includes a dome assembly having radially outer and inner liners joined thereto and defining therebetween a combustion zone. The dome assembly includes at least one annular dome having a pair of axially extending first flanges between which are disposed a plurality of circumferentially spaced apart carburetors for discharging a fuel/air mixture into the combustion zone for generating combustion gases. An annular heat shield includes a pair of axially extending legs integrally joined to a radially extending face in a generally U-shaped configuration, with the face including a plurality of circumferentially spaced apart ports disposed concentrically with perspective ones of the carburetors for allowing the fuel/air mixture to be discharged therefrom through the heat shield. At least one of the heat shield legs includes a plurality of circumferentially spaced apart mounting holes disposed adjacent to a respective one of the dome flanges, and a plurality of mounting pins are fixedly joined to the dome flange and extend radially through respective ones of the mounting holes without interference therewith for allowing unrestrained thermal movement between the heat shield and the dome while supporting the heat shield against axial pressure loads thereon. In a preferred embodiment, the dome assembly includes three domes having respective ones of the heat shield, and respective baffles are spaced from the heat shields for providing impingement cooling thereof

Liner mounting assembly

A mounting assembly includes an annular supporting flange disposed coaxially about a centerline axis which has a plurality of circumferentially spaced apart supporting holes therethrough. An annular liner is disposed coaxially with the supporting flange and includes a plurality of circumferentially spaced apart mounting holes aligned with respective ones of the supporting holes. Each of a plurality of mounting pins includes a proximal end fixedly joined to the supporting flange through a respective one of the supporting holes, and a distal end disposed through a respective one of the liner mounting holes for supporting the liner to the supporting flange while unrestrained differential thermal movement of the liner relative to the supporting flange

Segmented combustor

A combustor liner segment includes a panel having four sidewalls forming a rectangular outer perimeter. A plurality of integral supporting lugs are disposed substantially perpendicularly to the panel and extend from respective ones of the four sidewalls. A plurality of integral bosses are disposed substantially perpendicularly to the panel and extend from respective ones of the four sidewalls, with the bosses being shorter than the lugs. In one embodiment, the lugs extend through supporting holes in an annular frame for mounting the liner segments thereto, with the bosses abutting the frame for maintaining a predetermined spacing therefrom

Asiantuntijalausunto perustuslakivaliokunnalle

HE 13/2001 vp laiksi rangaistusten täytäntöönpanosta annetun lain muuttamisesta ja eräiksi siihen liittyviksi laeiks

Energy efficient engine high pressure turbine test hardware detailed design report

The high pressure turbine configuration for the Energy Efficient Engine is built around a two-stage design system. Moderate aerodynamic loading for both stages is used to achieve the high level of turbine efficiency. Flowpath components are designed for 18,000 hours of life, while the static and rotating structures are designed for 36,000 hours of engine operation. Both stages of turbine blades and vanes are air-cooled incorporating advanced state of the art in cooling technology. Direct solidification (DS) alloys are used for blades and one stage of vanes, and an oxide dispersion system (ODS) alloy is used for the Stage 1 nozzle airfoils. Ceramic shrouds are used as the material composition for the Stage 1 shroud. An active clearance control (ACC) system is used to control the blade tip to shroud clearances for both stages. Fan air is used to impinge on the shroud casing support rings, thereby controlling the growth rate of the shroud. This procedure allows close clearance control while minimizing blade tip to shroud rubs

The clash of business models in emerging economies: The case of wind energy industry in Africa

With the rise of emerging economy EE as main engine of global growth, the intensified competition in the wind energy industry and internationalization to EE, enterprises need to rethink and innovate their business models in order to succeed. The overall purpose of this article is to increase our understanding of the drivers of business model innovation (BMI) in EE, particularly in the wind energy industry. Qualitative, multi-case design is applied, where three cases within wind energy industry in Africa are studied - Siemens (Germany), Suzlon (India) and Goldwind (China). The results show that there is a difference between 'Developed-country Multinational Enterprises' (DMNEs), such as Siemens, and 'Emerging-county Multinational Enterprises', such as Suzlon and Goldwind, in the way they approach BMI in EE. To gain a competitive advantage in EE requires capabilities to deal with the specific EE related drivers of change: 1) fast growth and high demand combined with high uncertainty; 2) lower level of market-oriented socioeconomic development; 3) stronger governmental influence on the market; and 4) the need for simple, cheap and easy to maintain technologies. Therefore, it is important that managers position their enterprises in the EE first as local players and only then as multinationals. Our study indicates that future research should focus on the main elements and the drivers of change that would shape BMI by adding new variables, specifically related to EE

Method for providing concentricity of pilot fuel assembly in a combustor

Concentric installation of a pilot fuel assembly in an opening in a gas turbine combustor casing is achieved by providing a boss having at least two flat surfaces which are perpendicular to each other on the combustor casing surrounding the opening and a mounting flange having at least two flat surfaces which are perpendicular to each other on the pilot fuel assembly. The pilot fuel assembly is concentrically installed to the combustor casing by inserting the assembly into the combustor casing opening, and moving the pilot fuel assembly as far as it will go in a first direction substantially parallel to one of the flat boss surfaces. The distance between the other flat boss surface and one of the flat flange surfaces is then taken. Next, the pilot fuel assembly is moved in the direction opposite the first direction, at which point, the distance between the same two flat surfaces is again measured. Lastly, the pilot fuel assembly is located at a position where the distance between the two measuring surfaces is equal to the average of the first and second measurements. If desired, these steps can be repeated back and forth along an axis perpendicular to the first and second directions

Effect of Time and Rate of Application of Nitrogen on The Yield of the Mexican Wheat under the Semi-arid Conditions of Tunisia

The effect of the time and rate of application of nitrogen on the yield of high yielding varieties of wheat was studied under the semiarid conditions of Northern Tunisia. Analysis of the experimental data showed that nitrogen increased the yield of wheat in most locations which were chosen for this experiment. In high rainfall areas, late application of nitrogen (tillering, jointing stages) was more effective than early applications. The optimum yield was obtained by applying 90 kilograms of nitrogen per hectare. In the medium to low rainfall area, early applications (seeding time) were more effective than the late ones. The optimum yield was obtained by applying 67 kilograms of nitrogen per hectare. The yields varied from one location to another. This variability was found to be very dependent on the amount and distribution of the rainfall, thus moisture in the soil and the residual nitrogen