Polar and nonpolar lipids and their fatty acid composition of a fewFusarium species

A few species ofFusarium have been evaluated for their potential to produce lipids. The isolates under investigation exhibited wide variation with respect to the mycelial weight, total lipid content and percentage composition of polar and nonpolar lipids in which triglycerides were the major components (81–90%). Palmitic, stearic, oleic and linoleic acids were the major fatty acids in both the fractions. The polar lipids contained higher levels of linoleic acid, whereas nonpolar lipids contained oleic acid as the predominant acid. Nonpolar lipids were more saturated than polar lipids.     

Electrokinetic properties of polypropylene‐layered silicate nanocomposite fibers

Nanocomposite fibers based on polypropylene (PP) polymer were prepared with different content of nanofiller. Filaments were spun from an isotactic iPP homopolymer. Montmorillonite modified by N,N‐dimethyl‐N,N dioctadecylammonium cations was used for preparation of PP nanocomposite fibers. A PP grafted with acrylic acid was added as a coupling agent. Nanocomposite fibers were characterized, i.e., the surface morphology of PP nanocomposite fibers was observed and surface properties were defined by electrokinetic properties determination by zeta potential measurements. For particle distribution observation the plasma etching was involved as a method for sample preparation. The addition of nanoparticles has an impact on ZP value of nanofilled fibers, however, isoelectric point IEP is not significantly influenced by different concentrations of nanofiller. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Creep behavior of porous La0.6Sr0.4Co0.2Fe0.8O3-δ substrate material for oxygen separation application

Advanced oxygen transport membrane designs consist of a thin functional layer supported by a porous substrate material that carries mechanical loads. Creep deformation behavior is to be assessed to warrant a long-term reliable operation at elevated temperatures. Aiming towards an asymmetric composite, the current study reports and compares the creep behavior of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) perovskite porous substrate material with different porosity and pore structures in air for a temperature range of 800–1000?°C. A porosity and pore structure independent average stress exponent and activation energy are derived from the deformation data, both being representative for the LSCF material. To investigate the structural stability of the dense layer in an asymmetric membrane, sandwich samples of Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ (BSCF) and La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) with porous substrate and dense layers on both side were tested by three-point bending with respect to creep rupture behavior of the dense layer. Creep rupture cracks were observed in the tensile surface of BSCF, but not in the case of LSCF.     

Investigation of rhombohedral-cubic phase transition of La0.58Sr0.4Co0.2Fe0.8O3-δ using high temperature XRD

The phase transition of the La_0.58Sr_0.4Co_0.2Fe_0.8O_3-δ oxygen transport membrane material has been investigated by X-ray diffraction at elevated temperatures. It has a rhombohedral symmetry at room temperature that transforms to a cubic symmetry at operation relevant higher temperatures, which was investigated in detail in the current work on the basis of bar type and powder specimens and discussed in terms of correlations with mechanical behavior.     

One method for simplified manipulator model construction and its application in quazioptimal trajectory synthesis

In this paper a computer method for automatic setting of simplified dynamic models of open, active mechanisms is proposed. The algorithm is based on the well-known method of general theorems of mechanics for automatic setting of the complete model of these mechanisms. The simplified model takes into account inertial and gravitational terms, while the influence of Coriolis and centrifugal forces is neglected. The accuracy of the simplified model is examined on several examples. The simplified model is also utilized for optimal manipulator trajectory synthesis. It is shown that the use of the simplified model considerably reduces computational time, and at the same time ensures the same optimization results as the use of the complete dynamic model.     

Finite element simulations of the loading and deformation of plywood seat shells

Modern 3D modelling software reduces the need for a large number of prototypes, means fewer product-development cycles and lower costs (time/cost), as well as improving the quality of furniture designs. However, the mechanical testing of final products is still required in order to confirm the simulation results. In this study the theoretical behaviors of different plywood seating shells (using the SolidWorks^® FEM simulation software) were compared with the real results obtained using tests to measure the deformation of the backrest. The deviations of the actual deformation from the simulation were significant for the different shells and increased with loading above the elastic deformation limit of the material. It was concluded that the SolidWorks^® simulation software could be effectively used in the calculation of the component displacements, strains, and stresses of seat designs subject to internal and external loads.     

A high-pressure cell for kinetic studies on gas hydrates by powder x-ray diffraction

A new high-pressure-low-temperature cell was developed for in situ observations of gas hydrates by powder x-ray diffraction. The experimental setup allows investigating hydrate formation and dissociation as well as transformation processes between different hydrate crystal structures as a function of pressure, temperature, and feed gas composition. Due to a continuous gas flow, the composition of the gas phase is kept constant during the whole experiment. This is crucial for the formation of mixed hydrates formed from feed gas mixtures that contain one or more components in low concentrations. The pressure cell can be used in a pressure range between 0.1 and 4.0 MPa and a temperature range between 248 and 298 K. First results of time-resolved measurements of a mixed structure II CH(4) + iso-C(4)H(10) hydrate and a structure I CO(2) hydrate are presented.     

Symbolic modeling in robotics: Genesis,applicaton, and future prospects

This survey article gives an overview of software packages for generating numerically efficient manipulator models in symbolic form, i.e. as computer programs written in a high-level language such as C or FORTRAN. We chronicle the history of computational robot dynamics and, to some extent, multibody systems dynamics. We survey several mechanical computer-aided engineering software packages because they have charted the course for symbolic robot modeling software. The attractive features of various programs regarding areas of application (vehicles, robots, satellites, etc.) and design possibilities (kinematic and dynamic analysis, modal analysis, optimization of mechanical design, numerical efficiency of generated symbolic models, etc.) are emphasized. Finally, as an example, we present the SYM program package in more detail and point out the new strategic area of robotics which has emerged during the last two years: computer-aided generation of control laws.