Finite Element Modeling of Small-Scale Tapered Wood-Laminated Composite Poles with Biomimicry Features1

Tapered composite poles with biomimicry features as in bamboo are a new generation of wood laminated composite poles that may some day be considered as an alternative to solid wood poles that are widely used in the transmission and telecommunication fields. Five finite element models were developed with ANSYS to predict and assess the performance of five types of composites members: a tapered hollow pole with webs (Pole-A), a tapered hollow pole without webs (Pole-B), a tapered solid composite pole (Pole-C), a uniform-diameter hollow pole with webs (Pole-D), and a uniform-diameter hollow pole without webs (Pole-E). The predicted deflection by these models agreed well with those of the experiment, and the predicted normal stress agreed with those calculated. The normal and shear stress distributions inside the members were investigated, and stress distributions in the XY and YZ planes are exhibited. As expected, the webs reduced the local shear stress and improved shear capacity, especially in the top and groundline regions where shear levels were the highest. The webs had little effect on the normal stress. Shear stress increased from the bottom to the top for the members with taper. Large shear stress concentration was predicted in a small region close to the groundlines. The models also predicted that the shear stress of the tapered hollow poles would decrease from the inside to the outside surfaces in XY plane

Effect of Cement/Wood Ratios and Wood Storage Conditions on Hydration Temperature, Hydration Time, and Compressive Strength of Wood-Cement Mixtures

This study investigated the effect of cement/wood ratios and wood storage conditions on hydration temperature, hydration time, and compressive strength of wood-cement mixtures made from six wood species: southern pine, white oak, southern red oak, yellow-poplar, sweetgum, and hickory. Cement/wood ratios varied from 13/1 to 4/1. Wood storage conditions consisted of air-dried and cold-stored wood. Results indicate that hydration temperature was drastically reduced, hydration time was prolonged, and compressive strength was reduced as cement/wood ratio was decreased. This effect was more pronounced for hardwood species and at lower cement/wood ratios. Cold storage of wood slightly increased hydration temperature and shortened hydration time of white oak and sweetgum but did not have any beneficial effect on the other four species. Results also indicate that mixtures with high cement/wood ratios used traditionally in laboratory for research purposes may not truly reflect the wood-cement compatibility at lower cement/wood ratios used in commercial production

Advanced Nurse Practitioners’ (Emergency) perceptions of their role, positionality and professional identity: a narrative inquiry

Aims To explore Advanced Nurse Practitioners' (Emergency) perceptions of their role, positionality and professional identity. Background Advanced nursing practice was formally established in the Republic of Ireland in 2001 with 336 Advanced Nurse Practitioners currently registered increasing to a critical mass of 750 by 2021. Advanced practitioners (Emergency) provide full emergency care for a specific cohort of clients with unscheduled, undifferentiated and undiagnosed conditions. Design Qualitative narrative inquiry using Bourdieu's concepts of habitus, field and capital as the theoretical framework was undertaken. Methods Data were collected in ten in‐depth interviews and thematic analysis applied. Results Five key themes emerged: participants' career pathways, personal and professional transitions, role dimensions and core concepts, position in the organisation and emergent professional identity. Role‐transitioning and a change in habitus, field and capital revealed the uniqueness of their nursing role. Minimising waiting times, timely patient care and patient satisfaction were key performance indicators. A heightened awareness regarding higher‐level decision‐making, autonomy and accountability are integral to advanced practice. Conclusion This study presents unique insights into the advanced nurse practitioner role covering recruitment, organisational culture changes required and support to ease transition emerged. Impact Better understanding the motivation to undertake the role, the transition experience and use of advanced practice skills‐sets will inform the targets for the future recruitment and retention of Advanced Nurse Practitioners are met nationally and internationally. Dissatisfaction with previous management roles and wanting to be clinically‐close to patients were motivations to follow an advanced practice clinical career trajectory. Positionality and emergent professional identity are key enablers ensuring advanced practitioners' roles demonstrate the attributes of advanced practice. Educators could use the findings to develop recruitment, retention and progression strategies. Disseminating the role and scopes of practice could positively influence collaborative models of service delivery and policy development

Statistical method on nonrandom clustering with application to somatic mutations in cancer

<p>Abstract</p> <p>Background</p> <p>Human cancer is caused by the accumulation of tumor-specific mutations in oncogenes and tumor suppressors that confer a selective growth advantage to cells. As a consequence of genomic instability and high levels of proliferation, many passenger mutations that do not contribute to the cancer phenotype arise alongside mutations that drive oncogenesis. While several approaches have been developed to separate driver mutations from passengers, few approaches can specifically identify activating driver mutations in oncogenes, which are more amenable for pharmacological intervention.</p> <p>Results</p> <p>We propose a new statistical method for detecting activating mutations in cancer by identifying nonrandom clusters of amino acid mutations in protein sequences. A probability model is derived using order statistics assuming that the location of amino acid mutations on a protein follows a uniform distribution. Our statistical measure is the differences between pair-wise order statistics, which is equivalent to the size of an amino acid mutation cluster, and the probabilities are derived from exact and approximate distributions of the statistical measure. Using data in the Catalog of Somatic Mutations in Cancer (COSMIC) database, we have demonstrated that our method detects well-known clusters of activating mutations in KRAS, BRAF, PI3K, and <it>β</it>-catenin. The method can also identify new cancer targets as well as gain-of-function mutations in tumor suppressors.</p> <p>Conclusions</p> <p>Our proposed method is useful to discover activating driver mutations in cancer by identifying nonrandom clusters of somatic amino acid mutations in protein sequences.</p

Interaction between plant species and substrate type in the removal of CO2 indoors

Elevated indoor concentrations of carbon dioxide [CO2] cause health issues, increase workplace absenteeism and reduce cognitive performance. Plants can be part of the solution, reducing indoor [CO2] and acting as a low-cost supplement to building ventilation systems. Our earlier work on a selection of structurally and functionally different indoor plants identified a range of leaf-level CO2 removal rates, when plants were grown in one type of substrate. The work presented here brings the research much closer to real indoor environments by investigating CO2 removal at a whole-plant level and in different substrates. Specifically, we measured how the change of growing substrate affects plants’ capacity to reduce CO2 concentrations. Spathiphyllum wallisii 'Verdi', Dracaena fragrans 'Golden Coast' and Hedera helix, representing a range of leaf types and sizes and potted in two different substrates, were tested. Potted plants were studied in a 0.15 m3 chamber under ‘very high’ (22000 lux), ‘low’ (~ 500 lux) and ‘no’ light (0 lux) in ‘wet’ (> 30 %) and ‘dry’ (< 20 %) substrate. At ‘no’ and ‘low’ indoor light, houseplants increased the CO2 concentration in both substrates; respiration rates, however, were deemed negligible in terms of the contribution to a room-level concentration, as they added ~ 0.6% of a human’s contribution. In ‘very high’ light D. fragrans, in substrate 2, showed potential to reduce [CO2] to a near-ambient (600 ppm) concentration in a shorter timeframe (12 hrs, e.g. overnight) and S. wallisii over a longer period (36 hrs, e.g. weekend)

Mechanical Properties of Small-scale Laminated Wood Composite Poles: Effects Of Taper and Webs

Laminated hollow wood composite poles represent an efficient utilization of the timber resource and a promising alternative for solid wood poles that are commonly used in the power transmission and telecommunication lines. The objective of this study was to improve the performance of composite poles by introducing the bio-mimicry concept into the design of hollow wood composite poles. Five laminated hollow wood composite poles with taper and plywood-made webs, acting like the nodes in the bamboo, were made and tested in cantilevered static bending. Results indicated that node-like webs had a positive effect on the integrity, static bending properties, and shear resistance of the members tested, and their strength performance is comparable to that of the solid wood composite poles. However, the laminated hollow wood composite poles with taper showed slightly lower resistance to horizontal shear as compared to the members without taper

Finite Element Analyses Of Wood Laminated Composite Poles1

Finite element analyses using ANSYS were conducted on orthotropic, polygonal, wood laminated composite poles subjected to a body force and a concentrated load at the free end. Deflections and stress distributions of small-scale and full-size composite poles were analyzed and compared to the results obtained in an experimental study. The predicted deflection for both small-scale and full-size composite poles agreed well with the experimental measurement. Maximum stress of a cantilever pole was in parabolic areas of the top and bottom skins near the ground line. The finite element model underestimated the deflection of full-size composite poles over a variable length from the ground line of the poles, depending on the loading levels. At a higher loading level, the finite element model might overestimate the deflection close to the free end of the full-size composite poles