In order to improve material flow behavior during friction stir welding and avoid root flaws of weld, a tool with a half-screw pin and a tool with a tapered-flute pin are suggested. The effect of flute geometry in tool pins on material flow velocity is investigated by the software ANSYS FLUENT. Numerical simulation results show that high material flow velocity appears near the rotational tool a...

The goal of language programs is to utilize language for effective communication. Due to the needs, interests, and motivations of language learners, they may show individual differences in their lan- guage learning. Materials used in language programs can be instructional, experiential, elucidative, or exploratory in that they can inform learners about the language, provide experience of the la...

The chemical composition and the particle size distribution of 37 maize silages produced in north-west of Portugal were determined. Mean dry matter (DM), crude protein (CP), neutral detergent ®bre (NDF) and starch were 288 33, 81 9, 502 45 and 229 54 g kgÿ1 DM, respectively. Particle size was determined by manual separation of fresh silage into three fractions: material >30 mm in length; materi...

Analysis of static bending, free vibration and buckling behaviours of functionally graded microplates is investigated in this study. The main idea is to use the isogeometric analysis in associated with novel four-variable refined plate theory and quasi-3D theory. More importantly, the modified couple stress theory with only one material length scale parameter is employed to effectively capture ...

A key issue in judging foreign accent is to isolate the phonetic component from potentially confounding higher-level factors such as grammatical or prosodic errors which arise when using natural sentence-length speech material. The current study evaluated accent and intelligibility ratings of children’s speech for isolated words spliced out of extemporaneous material elicited via a picture desc...

We show that the nonlinear phase shift produced by a ring resonator constructed from a given nonlinear optical material can be greater than the phase shift produced by a single pass through an infinite length of the same material when linear and nonlinear absorption are taken into consideration. The figure of merit (defined by the phase shift times the throughput) also improves for the ring res...

In this contribution an overview over a numerical scheme for the crack modelling of spruce wood under tensile loading is given. A material model for biaxially stressed spruce wood with consideration of the effect of knots on the strength properties has been developed. A necessary feature of this material model is its ability to treat cracks by means of the so-called smeared crack concept. For t...

on the circular curve, lateral acceleration affects comfort. on the spiral, both lateral acceleration and jerk affect comfort.  the determination of maximum curving speed on the basis of lateral acceleration only is not critical because the lateral acceleration is proportional to the square of speed whereas jerk is proportional to cubic power of speed. the maximum speed on a curve is thus signi...

Organometal halide perovskites are under intense study for use in optoelectronics. Methylammonium and formamidinium lead iodide show impressive performance as photovoltaic materials; a premise that has spurred investigations into light-emitting devices and photodetectors. Herein, the optical and electrical material properties of organometal halide perovskites are reviewed. An overview is given ...

I . The muscular system of Metridium consists of fields of relatively short musclefibres. In extension these may exceed i mm. in length but are only about 0-5/* thick. They can shorten to about a fifth of the extended length. The fibres consist almost entirely of densely staining material. They form a connected network. At least in some cases the cells seem to be in contact rather than to form ...