196 research outputs found
Predicting Success on the NCLEX-RN for Associate Degree Nursing Students from a Small Public University
The success of an associate degree nursing program is often dichotomized into either passing or failing the National Council Licensure Examination for registered nursing (NCLEX-RN). Not only are individual studentsâ nursing future dependent on successfully navigating this examination, but the licensing and accreditation of nursing education programs are determined by maintaining consistent first-time pass rates of their graduates. This study will investigate academic and demographic factors to determine significant predictors of first-time pass on the NCLEX-RN for the associate degree in nursing program at Shawnee State University
Blackwater and Beyond: Can Potential Plaintiffs Sue Private Security Companies for Due Process Violations via Exceptions to the State Action Doctrine, Including Through Section 1983 Actions?
Fatigue of polymer composites: Life prediction and environmental effects
Fiber reinforced polymer composites offer significant advantages over traditional structural materials, but also many challenges, particularly with regard to their long term behavior. The fatigue performance of composites has been explored for the last few decades but it is still difficult to predict the behavior of a particular material under different loading and environmental conditions. Many researchers have worked to develop fatigue life prediction models and others to characterize the effect of environmental changes on static composite material properties, but experimental work in both of these areas can be difficult to perform and thus many observations have not been fully understood.;In order to further explore the effect of environmental conditions on fatigue life, a regimen of test was performed on a glass/vinyl ester composite. The testing included bending fatigue tests, tension-tension fatigue tests, and immersion conditioned tension-tension fatigue tests, with each type being performed under varying environmental conditions in the forms of elevated temperatures and the presence of salt water. From the experimental data, it was observed that the presence of salt water caused as much as a 50% decrease in fatigue life but was dependent on the time of exposure and had little effect on short duration tests. Elevated temperatures had an even more detrimental effect and exhibited a linear relationship with the number of cycles to failure. Immersion conditioning at room temperature decreased the fatigue life of the material to around 50--65% while immersion conditioning at 100°F decreased the fatigue life to around 15--25%.;Additionally, a strain energy-based fatigue life prediction model proposed by researchers at the West Virginia University Constructed Facilities Center was evaluated by applying the model to data collected through the experimental work, as well as to a large amount of fatigue data from the DOE/MSU Composite Material Fatigue Database. Test results for 109 different composites (1254 individual tests) were analyzed. From the variety of coupon fatigue data used to evaluate the model, it was found that the model was able to fit GFRP materials with over 80% of the results falling within +/-5% of the log number of cycles to failure. The model was also shown to be able to predict the fatigue life of polyester GFRPs to within +/-5% of the log number of cycles to failure using only two experimental values with a success rate of over 75%; using three increased the success rate to over 80%, but using more had little effect on its accuracy. A single-sample estimation model based on resin volume fraction was also developed and had reasonable success with polyester GFRPs. Of the two component fatigue results tested, both were able to be predicted by the fatigue model to within +/-2.5% log error. The strain energy fatigue model appears to provide both a good fit and a good prediction for the tension-tension fatigue life of GFRP composite materials
Measuring Academic Integrity Perceptions and the Correlation with Ethical Reasoning
Here we share findings of student and faculty perceptions of academic integrity practices at two institutions, gaps between these perceptions, and how these perceptions may correlate with markers of ethical engineering identity formation. We hypothesize that a climate of informed ethical practices surrounding academic integrity supports higher levels of student outcomes on an ethical reasoning assessment. As part of this mixed methods study, engineering students indicated their perceptions via a confidential survey of how well faculty fulfill several best practices for supporting academic integrity: articulating clear policies, preventing cheating, and promoting the value of integrity in class. Students also self-reported their perceived achievement of ethical reasoning and what value they place on it. Student responses are compared with performance on an objective ethical-reasoning exam which involves applying a code of ethics to multiple-choice problems that are modeled after licensing exam ethics questions.
Engineering faculty indicated via an anonymized survey and individual interviews their perceptions of how well they fulfill the same best practices for supporting academic integrity as referenced above. Faculty also shared perceptions of the achievement level of student ethical reasoning and what value students place upon it. The gap of student vs. faculty perceptions is compared with student performance on the objective ethical-reasoning exam at one institution. We expected larger perception gaps would correlate to lower ethical reasoning performance. Although our data is not sufficient to support the hypothesis, the results contribute significantly to further investigation and future academic integrity work. Future work beyond the scope of this paper will seek to lower the perception gap by identifying and motivating better faculty support for student academic integrity, which is hoped to lead to higher student outcomes. The work reported in this paper is designed to assess needs and serve as the background to launch future changes in academic integrity education and practices within the two Engineering Schools studied
Forming Congnitive Connections: Desktop Learning Modules, Structural Analysis Software, and Full-Scale Structures
One of the biggest challenges in teaching civil engineering students a theory-intensive course like structural analysis is helping students make the connection between the engineering mechanics taught at the front of the room and how those concepts define the real behavior of actual engineered structures. Absent this connection, students will often learn how to successfully perform the mathematical functions on their homework assignments but lack confidence in their ability to apply the same concepts to the analysis or design of an actual structure. Common ways to try to provide this real-world application of structural analysis principles include the use of small-scale physical models, often referred to as desktop learning modules (DLMs), software modeling, or case studies of full-scale structures. Each of these options possesses a significant limitation when it comes to helping students form cognitive connections: DLMs often lack adaptability or measurability, software helps provide visualization of engineering mechanics but lacks a connection to actual physical behavior, and full-scale structures are rarely able to be loaded to produce observable behavior. An ideal learning experience for students would include the synthesis of all of these tools to help students develop cognitive connections between mechanics principles, engineering design tools, and real-world structures through hands-on and problem-based learning.
A popular, recently developed, commercially available structural modeling DLM (Mola Structural Kit; no association with the authors) provides a high enough level of structural simulation and adaptability that it should allow for the kind of learning synthesis that has traditionally been challenging to produce. The Mola DLM permits students to create a variety of structural models that can reasonably approximate case studies of real structural behaviors in a manner that can be measured and compared to models developed using structural analysis software. The purpose of this study is to evaluate the effectiveness of an approach combining RISA 3D structural engineering software, the Mola physical model, and examples from actual structural systems at helping students form correct cognitive connections between principles of engineering mechanics and the behaviors of real structures.
Preparation for this study involved mechanically characterizing Mola components, developing parameters for implementation in structural analysis software, and validating the process of comparison between physical and computational models. Once the concept was confirmed to be practicable, worksheet-driven activities were developed and conducted in two undergraduate engineering classes. For these activities, students worked in small groups as they considered real-world applications of either portal frames or lateral force resisting systems, built Mola and structural analysis software models that reflected these real structural systems, then compared the modeled behaviors to practical applications of these concepts. Assessment was conducted via a mixed methods study using quantitative pre- and post-assessments and a small selection of follow-up interviews. Results suggest that students completing the activities demonstrated an increased ability to connect the concepts displayed by the physical models to the behaviors of the computational models and the applications in real-world structures. However, these gains did not seem to be uniform across all students, and modifications to the activity in future iterations may be able to further increase this and similar activitiesâ effectiveness
Macro and micromechanics analysis of short fiber composites stiffness: The case of old newspaper fibers-polypropylene composites
Stiffness is one of the most relevant characteristics of composite materials. Natural wood fibers have demonstrated their ability to increase the Young's moduli of composite materials, and old newspapers are a potential source of reinforcing fibers for composite materials. There are some micromechanic models to predict the Young's modulus of composite materials, and one of the input data is the intrinsic modulus of their fibers. This intrinsic modulus is a value which is difficult or impossible to measure in the case of wood fibers, due to their measures. This paper evaluates the stiffening abilities of old newspaper fibers and the possibility to back calculate the value of the intrinsic Young's Modulus by means of micromechanic models. Different percentages of old newspaper fibers were compounded with polypropylene (PP). Micromechanics of the fibers were obtained using Hirsch model, Cox-Krenchel's model, Tsai-Pagano model and Halpin-Tsai equations. The most important
results were the average intrinsic Young's modulus of the fibers, the mean orientation angle and the mean modulus efficiency factor.Serrano, A.; Espinach, FX.; Tresserras, J.; Rey Tormos, RMD.; Pellicer, N.; Mutje Pujol, P. (2014). Macro and micromechanics analysis of short fiber composites stiffness: The case of old newspaper fibers-polypropylene composites. Materials and Design. 55:319-324. doi:10.1016/j.matdes.2013.10.011S3193245
Thermal properties comparison of hybrid CF/FF and BF/FF cyanate ester-based composites
[EN] Insights within thermal expansion, conductivity, and decomposition dependencies with temperature on symmetrical and
unsymmetrical layered carbon (CF) or basalt (BF) fabrics in combination with flax fibers (FF) were approached. Driven by
commercial application and environmental concerns, the paper draws attention on a modified formula of cyanate ester with
a common epoxy resin under an optimized ratio of 70:30 (vol%) as well as on the hybrid reinforcements stacking
sequences. Synergetic effects were debated in terms of the CF and BF stacking sequences and corresponding volume
fraction followed by comparisons with values predicted by the deployment of hybrid mixtures rules (RoHM/iRoHM). CF
hybrid architectures revealed enhanced effective thermophysical properties over their BF counterparts and both over the
FF-reinforced polymer composite considered as a reference. Thermal conductivities spread between 0.116 and
0.299 W m-1 K-1 from room temperature up to 250 C on all hybrid specimens, giving rise to an insulator character.
Concerning the coefficient of thermal expansion, CF hybrid architectures disclosed values of 1.236 10-6 K-1 and
3.102 10-6 K-1 compared with BF affine exhibiting 4.794 10-6 K-1 and 6.245 10-6 K-1, respectively, with an increase
in their volume fraction.The corresponding author gratefully acknowledges the financial assistance of German Academic Exchange Service-DAAD that enabled and supported the internship with Fraunhofer Research Institution for Polymeric Materials and Composites-PYCO, Germany. Many thanks go to Dr. Christian Dreyer and Dr. Maciej Gwiazda for the resin formula and access to the composite manufacturing technology.Motoc, DL.; FerrĂĄndiz Bou, S.; Balart, R. (2018). Thermal properties comparison of hybrid CF/FF and BF/FF cyanate ester-based composites. Journal of Thermal Analysis and Calorimetry. 133(1):509-518. https://doi.org/10.1007/s10973-018-7222-yS5095181331Assarar M, Zouari W, Sabhi H, Ayad R, Berthelot J-M. Evaluation of the damping of hybrid carbonâflax reinforced composites. Compos Struct. 2015;132:148â54.Duc F, Bourban PE, Plummer CJG, MĂ„nson JAE. Damping of thermoset and thermoplastic flax fibre composites. Compos A Appl Sci Manuf. 2014;64:115â23.Saba N, Jawaid M, Alothman OY, Paridah MT. A review on dynamic mechanical properties of natural fibre reinforced polymer composites. Constr Build Mater. 2016;106:149â59.Tian H, Zhang S, Ge X, Xiang A. Crystallization behaviors and mechanical properties of carbon fiber-reinforced polypropylene composites. J Therm Anal Calorim. 2017;128(3):1495â504.Alvarez V, Rodriguez E, VĂĄzquez A. Thermaldegradation and decomposition of jute/vinylester composites. J Therm Anal Calorim. 2006;85(2):383â9.Manfredi LB, RodrĂguez ES, Wladyka-Przybylak M, VĂĄzquez A. Thermal degradation and fire resistance of unsaturated polyester, modified acrylic resins and their composites with natural fibres. Polym Degrad Stab. 2006;91(2):255â61.Lazko J, Landercy N, Laoutid F, Dangreau L, Huguet MH, Talon O. Flame retardant treatments of insulating agro-materials from flax short fibres. Polym Degrad Stab. 2013;98(5):1043â51.Bar M, Alagirusamy R, Das A. Flame retardant polymer composites. Fibers Polym. 2015;16(4):705â17.Kollia E, Loutas T, Fiamegkou E, Vavouliotis A, Kostopoulos V. Degradation behavior of glass fiber reinforced cyanate ester composites under hydrothermal ageing. Polym Degrad Stab. 2015;121:200â7.Jawaid M, Abdul Khalil HPS. Cellulosic/synthetic fibre reinforced polymer hybrid composites: a review. Carbohyd Polym. 2011;86(1):1â18.Azwa ZN, Yousif BF, Manalo AC, Karunasena W. A review on the degradability of polymeric composites based on natural fibres. Mater Des. 2013;47:424â42.H-y Cheung, M-p Ho, K-t Lau, Cardona F, Hui D. Natural fibre-reinforced composites for bioengineering and environmental engineering applications. Compos B Eng. 2009;40(7):655â63.Dittenber DB, GangaRao HVS. Critical review of recent publications on use of natural composites in infrastructure. Compos A Appl Sci Manuf. 2012;43(8):1419â29.Faruk O, Bledzki AK, Fink H-P, Sain M. Biocomposites reinforced with natural fibers: 2000â2010. Prog Polym Sci. 2012;37(11):1552â96.Praveen RS, Jacob S, Murthy CRL, Balachandran P, Rao YVKS. Hybridization of carbonâglass epoxy composites: an approach to achieve low coefficient of thermal expansion at cryogenic temperatures. Cryogenics. 2011;51(2):95â104.Jawaid M, Abdul Khalil HPS, Alattas OS. Woven hybrid biocomposites: dynamic mechanical and thermal properties. Compos A Appl Sci Manuf. 2012;43(2):288â93.Swolfs Y, Gorbatikh L, Verpoest I. Fibre hybridisation in polymer composites: a review. Compos A Appl Sci Manuf. 2014;67:181â200.Rojo E, Alonso MV, Oliet M, Del Saz-Orozco B, Rodriguez F. Effect of fiber loading on the properties of treated cellulose fiber-reinforced phenolic composites. Compos B Eng. 2015;68:185â92.LeGault M. Natural fiber composites: market share, one part at the time. Compos World. 2016;5(2):68â75.Joshi SV, Drzal LT, Mohanty AK, Arora S. Are natural fiber composites environmentally superior to glass fiber reinforced composites? Compos A Appl Sci Manuf. 2004;35(3):371â6.Wambua P, Ivens J, Verpoest I. Natural fibres: can they replace glass in fibre reinforced plastics? Compos Sci Technol. 2003;63(9):1259â64.Bertomeu D, GarcĂa-Sanoguera D, Fenollar O, Boronat T, Balart R. Use of eco-friendly epoxy resins from renewable resources as potential substitutes of petrochemical epoxy resins for ambient cured composites with flax reinforcements. Polym Compos. 2012;33(5):683â92.Alam M, Akram D, Sharmin E, Zafar F, Ahmad S. Vegetable oil based eco-friendly coating materials: a review article. Arab J Chem. 2014;7(4):469â79.Bakare FO, Ramamoorthy SK, Ă
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Use of green composites for manufacturing small boats in the Amazon: numerical and experimental evaluations
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