Mercerization of Cotton for Strength with Special Reference to Aircraft Cloth

The object of the present investigation was to determine the conditions for mercerizing cotton yarn to obtain the maximum strength for a given weight. Apparatus for controlling the variables was built and yarns were mercerized with it under systematically varied conditions of tension, time, temperature, and concentration of caustic soda. The strongest conclusion to be drawn from this work is that the strongest mercerized yarn of a given count from a given quality of cotton is obtained under the following conditions: 1. use of low-twist yarn obtained with twist multipliers from 2.2 to 3; 2. thorough pretreatment of the yarn to remove all extraneous materials; 3. mercerization at a temperature of 0 C or lower; 4. use of sufficient tension during mercerization to prevent the yarn from contracting more than 3 percent. 5. Use of caustic solution having a concentration of 10 percent or higher; 6. the time of mercerization to be 5 minutes. The resulting yarn should be 40 to 100 percent stronger than the original yarn of the same weight

Crown Ether-Modified Clays and their Polystyrene Nanocomposites

Crown ether-modified clays were obtained by the combination of sodium and potassium clays with crown ethers and cryptands. Polystyrene nanocomposites were prepared by bulk polymerization in the presence of these clays. The structures of nanocomposites were characterized by X-ray diffraction and transmission electron microscopy. Their thermal stability and flame retardancy were measured by thermogravimetric analysis and cone calorimetry, respectively. Nanocomposites can be formed only from the potassium clays; apparently the sodium clays are not sufficiently organophilic to enable nanocomposite formation. The onset temperature of the degradation is higher for the nanocomposites compared to virgin polystyrene, and the peak heat release rate is decreased by 25% to 30%

Duality and neutral pion electroproduction

The implications of Duality, in the form of Finite Energy Sum Rules, are examined for the photoproduction and electroproduction of neutral pions off protons. The Collins and Fitton model of high energy pion photoproduction is extended to accommodate the features of the photo production FESH. The analysis is extended to electro production and it is shown that a simple modification of the model will fit the electroproduction cross-section. The implications of this modification are discussed

General Anesthetic Induction Sequence High Fidelity Simulation: Determining Efficacy Among Novice Student Registered Nurse Anesthetists

Background High Fidelity Simulation (HFS) is used across multiple health professions. Despite the wide variety of clinical experiences that Student Registered Nurse Anesthetists (SRNA) possess prior to training, the induction sequence to a General Anesthetic (GA) is a daunting task. Although the efficacy of HFS has been widely studied within undergraduate nursing programs, there are no studies published determining the efficacy of HFS on SRNA training. The purpose of this study was to determine the efficacy of simulation training amongst entry-level SRNA’s and examine any individual participant factors that may influence clinical performance within HFS. Methods • Human subjects were protected (Spokane IRB ID: STUDY18000465) • Pilot study participants recruited from 1st semester SRNAs in the Doctorate of Nurse Anesthesia Practice (DNAP) • Full study participants recruited from prospective DNAP students • Primary endpoints: efficacy of GA induction sequence HFS • Secondary endpoints: individual participant factors that may influence clinical performance within HFS • Scoring tool developed to measure primary outcome (Figure 2) • PowerPoint and didactic lecture provided to all participants • Pretest assessment following didactic training, using scoring tool, prior to HFS • Participants guided through HFS and subsequently debriefed • Posttest assessment completed following HFS using scoring tool • Each participant allotted 60 minutes for individual HFS session • Analysis of variance utilizing a waitlisted study design • A priori confidence level (α \u3c 0.05) Discussion Our sufficiently powered study detected a 29.0% (mean pre-test 23.7, mean post-test 33.4) improvement in Simulation Assessment Tool scores following HFS (p \u3c 0.001). Despite variations in pre HFS scores, post HFS scores remain homogeneous across all participants confirming the effectiveness of our training. Our study also indicated that there were no statistically significant group differences in HFS pre-test scores amongst the participants for the demographic factors we assessed; type of ICU (p=0.76), years of ICU experience (p=0.36), and age (p=0.91). GA induction sequence training using HFS was proven to be effective among novice SRNA’s. In alignment with the current research evidence, the use of HFS among SRNA’s may help to improve learning, self-efficacy, and subsequently patient safety. Doctoral nurse anesthesia programs should consider the integration of HFS throughout program curriculum.https://digitalcommons.psjhealth.org/other_pubs/1120/thumbnail.jp

Investigation of nanodispersion in polystyrene-montmorillonite nanocomposites by solid state NMR

Nanocomposites result from combinations of materials with vastly different properties in the nanometer scale. These materials exhibit many unique properties such as improved thermal stability, reduced flammability, and improved mechanical properties. Many of the properties associated with polymer–clay nanocomposites are a function of the extent of exfoliation of the individual clay sheets or the quality of the nanodispersion. This work demonstrates that solid-state NMR can be used to characterize, quantitatively, the nanodispersion of variously modified montmorillonite (MMT) clays in polystyrene (PS) matrices. The direct influence of the paramagnetic Fe3, embedded in the aluminosilicate layers of MMT, on polymer protons within about 1 nm from the clay surfaces creates relaxation sources, which, via spin diffusion, significantly shorten the overall proton longitudinal relaxation time (T1 H). Deoxygenated samples were used to avoid the particularly strong contribution to the T1 H of PS from paramagnetic molecular oxygen. We used T1 H as an indicator of the nanodispersion of the clay in PS. This approach correlated reasonably well with X-ray diffraction and transmission electron microscopy (TEM) data. A model for interpreting the saturation-recovery data is proposed such that two parameters relating to the dispersion can be extracted. The first parameter, f, is the fraction of the potentially available clay surface that has been transformed into polymer–clay interfaces. The second parameter is a relative measure of the homogeneity of the dispersion of these actual polymer–clay interfaces. Finally, a quick assay of T1 H is reported for samples equilibrated with atmospheric oxygen. Included are these samples as well as 28 PS/MMT nanocomposite samples prepared by extrusion. These measurements are related to the development of highthroughput characterization techniques. This approach gives qualitative indications about dispersion; however, the more time-consuming analysis, of a few deoxygenated samples from this latter set, offers significantly greater insight into the clay dispersion. A second, probably superior, rapid-analysis method, applicable to oxygen-containing samples, is also demonstrated that should yield a reasonable estimate of the f parameter. Thus, for PS/MMT nanocomposites, one has the choice of a less complete NMR assay of dispersion that is significantly faster than TEM analysis, versus a slower and more complete NMR analysis with sample times comparable to TEM, information rivaling that of TEM, and a substantial advantage that this is a bulk characterization method. © 2003 Wiley Periodicals, Inc.* J Polym Sci Part B: Polym Phys 41: 3188–3213, 200