Two types of one-handed exact helical polymers, coil- and screw-shaped polymers, were synthesized by the two-point-covalent-linking protocol using C2-chiral spirobifluorene (SBF) and C2- or C(s)-symmetric anthraquinone spacers. Central to this protocol is a new aromatic ring-forming reaction based on the stepwise reductive cyclization of bis(aryloxy group)-substituted anthraquinone derivatives....

A dynamic hip screw (DHS) remains the implant of choice for stabilization of trochanteric fractures because of its favourable results and low rate of non-union or hardware failure, but complication rates of the DHS are higher in unstable and osteoporotic trochanteric fractures. The proponents of the dynamic helical hip system (DHHS) report that it has the potential to decrease the cut-out rates...

Surface finishing is one of the most significant steps in industries which are engaged with surface quality. Finishing by magnetic field is a new method of surface finishing. In this process, machining is executed in mechanical way and semi-homogeneous abrasive slurry performs finishing of surfaces. Needed force to grind surfaces is made by magnetic field. Therefor this method is considered as ...

The latest development in screw compressor (helical lobed compressor) rotor profile design and rotor manufacturing machinery have prioritized basic rotor profile surface, lead and divide. However, one error that at frrst looks very basic but at the same time almost impossible to eliminate, is dealt with in this paper. The error is rotor runout.

2014 The stability of a screw dislocation in a SmA phase submitted to a dilative or compressive strain normal to the layers is investigated. It is shown that the screw line transforms to a helical line, whose handedness depends on the signs of the Burgers’ vector and of the strain. For small strains the process necessitates some activation energy; there is a critical strain above which it is sp...

We have identified an array of more than 500 repetitive sequences flanking the hsr gene, which encodes the major surface protein of the ferret pathogen Helicobacter mustelae. The repeats show identity exclusively to the amino-terminal half of Hsr. Analysis of Hsr from three strains indicated variability of exposed epitopes. Characterization of an hsr mutant showed that Hsr is not an adhesin.

We present a method of helical long-period fiber grating (H-LPFG) fabrication by use of a CO2 laser for use as an optical torque sensor. A conventional optical fiber grating has periodic vertical index changes along its fiber axis, but a H-LPFG has a screw-type index modulation. The helical index modulation is obtained with the asymmetric index change caused by a single-side laser beam exposure...

Well dispersion or intercalation/exfoliation of nanoscale fillers (such as nano-CaCO3 and nano-clay) in polymer matrix is currently not easy to be achieved. Supercritical carbon dioxide (ScCO2) has been reported to have great potential for facilitating the dispersion or intercalation/exfoliation of the nanoscale fillers in polymer matrix. So, in this paper, the effects of dissolved ScCO2 on the...

Thermal stability is of major importance in polymer extrusion, where product quality is dependent upon the level of melt homogeneity achieved by the extruder screw. Extrusion is an energy intensive process and optimisation of process energy usage while maintaining melt stability is necessary in order to produce good quality product at low unit cost. Optimisation of process energy usage is timel...

The Hibiscus sabdariffa calyxes' residue (HSR) remained after the extraction of beverage is discarded which contributes to environmental pollution. The objective of this study was to explore the suitability of incorporating different amount of HSR (0%, 1.25%, 2.5%, 3.75%, and 5.0%) in crackers to enhance dietary fiber and antioxidant content. Physicochemical properties, antioxidants activity, n...