Microstructure of high modulus solid state extruded polyethylene: 2. X-ray scattering studies of 12, 24 and 36 extrusion draw ratio

The microstructure of a series of solid state extruded polyethylene fibres was examined by wide- and small-angle X-ray scattering. By measuring absolute intensities using a two dimensional position sensitive detector, accurate values of the small-angle invariant for anisotropic samples were obtained. This measurement coupled with wide-angle X-ray scattering and d.s.c. permitted determination of the density of the noncrystalline component. The use of a two phase model for solid state extruded polyethylene is justified if consideration is given to the effective densities of the crystalline and noncrystalline phases, which change with deformation. The effective density of the crystalline phase decreases by 1% (0.999–0.990 g cm^?3) from the unextruded billet compared to a 36 draw ratio extrudate, while the noncrystalline phase density increases by 6% (0.84–0.89 g cm^?3). These changes lead to an overall decrease in the mean squared electron density fluctuation of 63%. The average axial crystallite length measured by wide-angle X-ray scattering increases with extrusion draw ratio while the SAXS long period decreases and weakens considerably. These observations and the electron microscopy results from the previous paper, (Polymer, 1982, 23, 1069), are fully consistent with the key features of the Peterlin model of fibre microstructure.     

The educo‐politics of curriculum development: A response to Peter Fensham's ‘time to change drivers for scientific literacy’

Abstract

Fensham (2002) proposes that we modify the composition of those involved in the political power struggle ('educo‐politics') over who determines the science curriculum. He suggests that ‘societal experts’ are better situated than academic scientists to decide what knowledge is worth having, although his plan for curriculum development includes academic scientists deciding what science content supports the issues initially identified by societal experts. However, Fensham's proposal lacks the educo‐politics needed to counter the customary devious educo‐politics we have come to expect from those who support the status quo—particularly some academic scientists. Fensham's proposal gives academic scientists unnecessary political advantage. School science for an informed citizenry will continue to be marginalized if its supporters do not win at educo‐politics. Curriculum developers have few universal principles of action to follow other than Sgt. Jablonski's (of Hill Street Blues) ’Do it to them before they do it to you.’ This article clarifies some of these Jablonskian counter‐educo‐politics.     

Aberrant protein expression in plasma and kidney tissue during experimental obstructive nephropathy

Kidney failure is a major health problem worldwide. Patients with end-stage renal disease require intensive medical support by dialysis or kidney transplantation. Current methods for diagnosis of kidney disease are either invasive or insensitive, and renal function may decline by as much as 50% before it can be detected using current techniques. The goal of this study was, therefore, to identify biomarkers of kidney disease (associated with renal fibrosis) that can be used for the development of a non-invasive clinical test for early disease detection. We utilized two protein-profiling technologies (SELDI-TOF MS and 2-D) to screen the plasma and kidney proteome for aberrantly expressed proteins in an experimental mouse model of unilateral uretric obstruction, which mimics the pathology of human renal disease. Several differentially regulated proteins were detected at the plasma level of day-3-obstructed animals, which included serum amyloid A1, fibrinogen α, haptoglobin precursor protein, haptoglobin and major urinary proteins 11 and 8. Differentially expressed proteins detected at the tissue level included ras-like activator protein 2, haptoglobin precursor protein, malate dehydrogenase, α enolase and murine urinary protein (all p<0.05 versus controls). Immunohistochemistry was used to confirm the up-regulation of fibrinogen. Interestingly, these proteins are largely separated into four major classes: (i) acute-phase reactants (ii) cell-signaling molecules (iii) molecules involved in cell growth and metabolism and (iv) urinary proteins. These results provide new insights into the pathology of obstructive nephropathy and may facilitate the development of specific assay(s) to detect and monitor renal fibrosis.     

Fiber Bragg grating tether used to measure drag forces in neutral buoyancy flow tank tests

The drag exerted on neutrally buoyant tethered spheres in a flow tank was measured as a function of flow rate. A unique solution to the problem was achieved using an optical fiber including a Bragg grating sensor as part of the tether. Measurements of the strain on the tether taken at flow rates between 0.14 and 0.33 m/s, were used to determine drag forces for spheres with diameters ranging from 40 to 100 mm. Vortex-induced vibration was observed in tests performed at Reynolds numbers from 5 x 10(3) to 4.5 x 10(4). The drag coefficients for these tests were found to range from 0.51 to 0.77.     

A short note on the effect of sample size on the estimation error in Cp

Process capability indices such as C_p are used extensively in manufacturing industries to assess processes in order to decide about purchasing. In practice, the parameter for calculating C_p is rarely known and is frequently replaced with estimates from an in-control reference sample. This article explores the optimal sample size required to achieve a desired error of estimation using absolute percentage error of different C_p estimates. Moreover, some practical tools are created to allow practitioners to find sample size in different situations.     

Electronic specific heat of overdoped Tl2Ba2CuO6+δ in a magnetic field

We have measured the magnetic field dependence of the electronic specific heat ^el (=C^el/T) of polycrystalline Tl₂Ba₂CuO₆₊ from 8 K to above T_c, for samples with T_c = 24 K to 72 K using a high resolution, differential technique. We find that in applied fields of up to 13 T the position of the specific heat jump does not shift significantly for any T_c. This is in strong disagreement with H_C2(T) inferred from magnetoresistance experiments on the same compound, where the resistive transition is shifted down considerably by similar fields. However, there is a dramatic collapse of the specific heat anomaly height in field — signifying a loss in entropy around T_c — compensated by a corresponding increase in ^el at lower temperatures. The superconducting anomaly is almost completely suppressed in 13 T for the lowest T_c sample, compared to a reduction of 65 % for the sample with T_c = 72 K. We find simple vertical scaling of ^el(T) — _n suggesting that the field forces a proportion of the superconductor into the normal state, while the remainder in the superconducting state is unaffected.     

Improving literacy and metacognition with electronic portfolios: Teaching and learning with ePEARL

Can an electronic portfolio that is both a multimedia container for student work and a tool to support key learning processes have a positive impact on the literacy practices and self-regulated learning skills of students? This article presents the findings of a yearlong study conducted in three Canadian provinces during the 2007–2008 school year initially involving 32 teachers and 388 students. Due to varying levels of implementation our final data set included 14 teachers and 296 students. Using a non-equivalent pre-test/post-test design, we found that grade 4–6 students who were in classrooms where the teacher provided regular and appropriate use of the electronic portfolio tool ePEARL (i.e., medium–high implementation condition, n = 7 classrooms and 121 students), compared to control students (n = 7 classrooms and 175 students) who did not use ePEARL, showed significant improvements (p < .05) in their writing skills on a standardized literacy measure (i.e., the constructed response subtest of the Canadian Achievement Test-4th ed.) and certain metacognitive skills measured via student self-report. The results of this study indicate that teaching with ePEARL has positive impacts on students’ literacy and self-regulated learning skills when the tool is used regularly and integrated into classroom instruction.     

The contribution of communications signals to noise exposure

Man-mounted miniature recording equipment has been used to measure the electroacoustic conditions obtaining in cockpits of aircraft and at the pilot's ear during operational sorties in the Royal Air Force. Although this paper considers the measurements taken that relate to the total noise exposure (noise dose) received by aircrew, the results apply equally to anyone who is exposed to high noise and requires communications.

Comparison of the noise at the ear with the cockpit noise gave a measure of headgear attenuation which was used to adjust a 1/3-octave filter. Playing cockpit noise tapes through this filter to a noise dose meter gave the noise dose that would have been experienced had there been no communications signals. The results showed that the communications signals at the ear, averaging 40% of the sortie time, are a major contributor to the total dose, and, without the signals, the dose averaged about 6 dB less. In view of the Health and Safety at Work Act, 1974, employers should be aware of the additional dose to which employees are exposed because of communications.

A method for the prediction of noise dose is proposed where communication takes place in a noisy environment.     

Seismic Performance and Deformation of Levees: Four Case Studies

During the 1989 Loma Prieta earthquake the Pajaro River levees near Watsonville, Calif., spread laterally at multiple locations. Four of these locations are discussed in this paper. At one location, an industrial facility was also damaged and a dispute arose as to whether lateral spreading of the adjacent levee was the cause. Stability analyses were made of the industrial site for conditions before, during, and after the earthquake. To confirm the findings, analyses were also made of three other nearby locations where the actual deformation was documented and the subsurface conditions are well defined. The calculated levee deformations at the four locations are quite consistent with the observed movements (up to 60 cm). This experience provides increased confidence in the methods of analysis described, for the characterized subsurface conditions, and the range of ground motions experienced. Additional analyses made using the more recently developed multilinear regression lateral-spreading model (e.g., Youd et al. in 1999) yielded inconsistent results.     

The Dark Side of Relational Pursuit: From Attraction to Obsession and Stalking,.

Review declaring pleasant surprise with this relatively short book on stalking. It contains 164 pages of text, and provides a thorough context for understanding and treating stalking behavior, including a focus on both victim and perpetrator. The book is divided into five chapters. The first of these defines the nature of stalking behavior. Stalking is defined as harmful conduct, which involves unwanted communication and repeated unwanted intrusion by one individual upon another. The review notes that stalking behavior has three defining characteristics--(a) relentless and persistent contact, which is (b) unwanted and (c) adverse to the recipient. It is further observed that there is no single motive for stalking, nor any specific psychological profile for the personality of stalkers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)