The Situational Judgment Test Validity Void: Describing Participant Response Processes

Situational judgment tests (SJTs) are used to measure important components of professional competence that cannot be assessed via traditional tests of knowledge and skills. Despite their increasing popularity, there is a significant gap in the validity evidence and research on the response process to support how SJTs measure their intended constructs. This study evaluated an SJT to examine: (1) the factors that influence the response process, (2) the role of experience in the response process, (3) the role of contextual features in the response process, and (4) whether individuals attempt to identify the construct being assessed. Thirty participants—15 students and 15 pharmacists—completed a 12-item SJT designed to measure empathy. Each participant engaged in an uninterrupted think-aloud interview while they completed an SJT followed by a cognitive interview that asked specific questions about their decision-making process. Results of the qualitative and quantitative analyses suggest that the SJT response processes include the complex integration of comprehension, retrieval, judgments, and response selections. In addition, job-specific knowledge and experiences comprised a significant portion of the retrieval process. Moreover, there was evidence that SJTs are highly contextual and that item characteristics such as setting, actors, or relationships can influence the response process. There was limited evidence to suggest individuals attempt to identify the construct being assessed. In summary, this study provides a comprehensive evaluation of the response process involved in SJTs using rigorous qualitative methodologies and it contributes to foundational steps to generate the validity evidence necessary to aid in score interpretation and future research.Doctor of Philosoph

Temperature and Moisture Influence on Compression-Recovery Behavior of Wood

The primary limitation of non-veneer wood composites for applications in moist environments is dimensional instability. Thickness instabilities from moisture absorption primarily result from damaged cell structures that recover upon absorption of moisture. Previous research has shown that manipulating the pressing parameters involved in the manufacture of non-veneer wood composites (i.e., temperature and moisture) can lead to a more dimensionally stable product. However, the precise phenomena controlling these changes are not fully defined. To understand development of pressing-induced damage, the large strain, compression-recovery behavior of wood and polyurethane (PUR) foam (i.e., as a model system) was studied at a variety of compression temperatures spanning the glassy to rubber transition. The behavior is then related to polymer phase transitions to discern the role of viscoelastic behavior in damage evolution. The elastic modulus (E) and yield stress (σy) were used to characterize the elastic region of compression, whereas fractional recovery (R) and dissipated energy (ΔE) represented the inelastic component. The PUR foam displayed a distinct glassy plateau region dominated by E, σy, and ΔE as well as low R. Wood with 22 and 12% MC behaved similarly to the elastomeric PUR foam; however, limits on environmental control prevented testing in the rubbery regime for the 12% MC samples. The E and σy also decreased with increasing compression temperature for ovendried yellow-poplar. However, in contrast to yellow-poplar with either 12 or 22% MC, an increase in ΔE was accompanied by a decrease in R with increasing compression temperature of the oven-dried yellow-poplar. An apparent change in mechanism occurs when compressing wood at high temperatures without moisture present. This change was attributed to kinetic effects such as thermal degradation or crosslinking reactions

A Model for Viscoelastic Consolidation of Wood-Strand Mats. Part I. Structural Characterization of the Mat Via Monte Carlo Simulation

A procedure using Monte Carlo simulation was developed to characterize the spatial structure of randomly formed, wood-strand mats. The simulation reproduces the number of strands in the centroids of imaginary strand columns of finite size. The vertical distances between the adjacent strands and the location of the column centroid relative to the constant length of each strand are also simulated. A data base was collected on realistic mats produced from strands of constant size and non-planar geometries (i.e., random bow, cup, and twist). The procedure can be used in a model for predicting the mechanical behavior of random strand mats during consolidation

A Model for Viscoelastic Consolidation of Wood-Strand Mats. Part II: Static Stress-Strain Behavior of the Mat

A solid mechanics model is developed to predict the static stress-strain behavior of randomly formed wood-strand mats during pressing. The procedure includes a Monte Carlo simulation for reconstructing the mat structure. During the early stages of mat displacement, the model computes the cumulative stress development from strand bending. As consolidation continues, the overlapping strands form solid columns. Hooke's Law, modified by a nonlinear strain function, governs the stress development in a finite number of these imaginary columns comprising the mat. Experimental results showed good agreement with the predicted stress response

Reducing Moisture Swell of Densified Wood With Polycarboxylic Acid Resin

A water-soluble polycarboxylic acid (PCA) resin was assessed for ability to limit moisture swelling of densified wood. Aspen flakes were treated in 0 (control), 1, 5, 10, and 20% PCA resin solutions and drained for 1, 10, and 20-min time periods. Following treatments, flakes were compressed to roughly 50% strain at 170°C. The PCA content of flakes significantly increased with increasing concentration and drain time. Water absorption and thickness swell of flakes decreased with increasing PCA content. Both water absorption and thickness swell of untreated flakes were over 100%; but for PCA-treated flakes, water absorption and thickness swell as low as 45% and 16%, respectively, were achieved. Irreversible thickness swell decreased with increasing PCA content, while reversible thickness swell remained relatively constant. The swelling coefficient decreased with increasing PCA content, a behavior that often is associated with bulking agents for treated, uncompressed wood. However, dynamic mechanical analysis further suggested that PCA resin acts as a cross-linking agent to stabilize the position of the collapsed cell walls

Sustainability of a long-term volunteer-based bird monitoring program : recruitment, retention and attrition

With an increasing demand and reliance on volunteers in a host of different sectors, the need for organisations to understand motivating factors behind volunteering, and how to retain volunteer services, is crucial. This paper examines the recruitment, retention and attrition among a group of volunteers participating in a long-term monitoring program for the critically endangered orange-bellied parrot Neophema chrysogaster. This project is one of the longest running of its type in Australia with more than 20 years of survey activities. Volunteers were most often recruited via other environmental agencies. Almost three-quarters of respondents had been involved in birdwatching or other bird monitoring activities usually in connection with conservation organisations. The modal response was an involvement of 10-20 years, with most other responses in the range 0-5 years. The majority intend to continue volunteering, but cited perceived health and time commitments as the main factors behind possible future decisions to cease volunteering. Respondents suggested improvements in the volunteer management of the program, and in particular, thought a personal \u27thank you\u27, would maintain motivation and participation

Fundamental Aspects of Wood Deformation Pertaining To Manufacture of Wood-Based Composites

During processing, wood-based composites are pressed using extreme heat and pressure for varying lengths of time. Evidence exists that the environmental conditions under which the wood densifies can alter the properties of both the solid wood and the composite product. Given the larger number and extreme nature of variables that exist during composite manufacture, it is imperative that the deformation process be understood from a fundamental standpoint. The objective of this research was to determine the applicability of basic materials engineering theory to the viscoelastic deformation of wood in transverse compression under a variety of temperatures and moisture contents.Theories of cellular solids were used to model the nonlinear compression behavior of small wood elements. For low-density woods, it was determined that cellular collapse can result from elastic buckling of the cell wall. The dependence of inelastic behavior of the gross wood on the elastic properties of the cell wall allows the time, temperature, and moisture dependence to be modeled with classical linear viscoelastic theory of amorphous polymers. Time-temperature-moisture superposition was shown to be applicable to stress relaxation data collected for temperatures between 39 and 99 C and moisture contents between 3 and 16%. The shift factors derived were described using free volume and entropy-based equations. This research demonstrates that wood behaves similarly under those conditions to the general class of cellular amorphous polymers. This conclusion opens many possibilities for experimentally and mathematically modeling the pressing of wood-based composites

TB127: Age and Thinning Effects on Wood Properties of Red Spruce (Picea rubens Sarg.)

Ten overstory red spruce were selected from a thinned stand and 1 0 from an unthinned stand. Average age of sample trees was approximately 80 years. Specific gravity reached a maximum at age 53 in the thinned stand and age 72 in the unthinned stand, after which it remained relatively constant. Stiffness reached a maximum at ages 35 and 50, and bending strength at ages 41 and 54; both remained relatively constant with further increases in age. Stiffness showed the largest relative difference between juvenile and mature wood, 22%, and specific gravity the smallest difference, 8%. Thinning did not adversely affect any of the properties, even though the width of some growth rings was increased by three to four times. These results suggest that (1) growth of mature red spruce stands can be increased by thinning without affecting wood physical properties, and (2) intensive management practices designed to shorten the rotation age may lead to stands that have not begun to produce mature wood before they are harvested. These short-rotation stands will contain a higher percentage of juvenile wood than stands presently being harvested, which means that pulp yields will decrease and the material will be less suitable for structural lumber.https://digitalcommons.library.umaine.edu/aes_techbulletin/1063/thumbnail.jp

Temperature Dependence Of Wood Surface Energy

A thorough understanding of the wood surface is required to engineer adhesive bonding in composite applications. A surface analysis technique, dynamic contact angle (DCA) analysis, was used to examine the effects of temperature on the wood surface as measured by the contact angle and surface energy. A hydrophobic surface transition was found on the wood surface at 60 C, which coincides with the glass transition of lignin as measured by differential scanning calorimetry. The change in the surface at the glass transition can be attributed to the diffusion of nonpolar molecular groups to the surface. This could be the result of the migration and deposition of extractives, reorientation of macromolecules, or a combination of the two. Similar behavior has been observed in synthetic amorphous polymers. Although the surface of wood is complex, the results indicate that it can be investigated and understood like synthetic polymer materials