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Physical and Digital Models for Timber Design and Analysis Courses
Get PDFAmong structural engineering education research, there is a limited number of studies on interactive learning tools and activities specifically for the timber design classroom to assist students in visualizing material behavior, vertical and lateral load paths, and construction sequence. Timber design courses within the undergraduate program in the Architectural Engineering department at California Polytechnic State University in San Luis Obispo (Cal Poly), place an emphasis on seismic and wind design. Therefore, the proposed learning tools and activities are intended to pair with an introduction to concepts in the American Wood Council’s National Design Specifications (NDS) and Special Design Provisions for Wind and Seismic (SDPWS).
A primary approach implemented in the timber course at Cal Poly was physical and digital models to strengthen student\u27s conceptual understanding of the directional properties of wood, mechanical connections, as well as gravity and lateral load flow. These included: Demonstration with drinking straw bundle and sawn lumber to demonstrate difference in behavior due to grain direction and under different types of forces, Kit consisting of manufactured lumber (I-joists and laminated-veneer lumber) and hardware samples (shear wall hold-down and joist hanger) sourced from various suppliers to expose students to commercial products available for timber design, Laterally braced column model that examines the effects of column section dimensions relative to the unbraced length on buckling load, Physical and digital diaphragm models that demonstrate the variations of sheathing layouts, per SDPWS Section 4.2.8, and allows students to investigate the appropriate application of layouts under various loading conditions, Digital library of three-dimensional (3-D) components for students to rapidly assemble a stacked shear wall they have designed to be able to investigate load flow and constructability in both 2-D and 3-D views.
Other course material included a homework packet based on a two-story residential project completed by the instructor’s firm, a handout that guides students through the analysis of members under bi-axial loading, and presentation material contributed by a firm with an expertise in mass timber (as alternative to hosting a guest presenter). Additional course activities include visits to a local project site and the college’s large-scale laboratory to learn about timber construction and behavior from other experts outside of the classroom setting.
Student surveys were conducted for a majority of the various pedagogical techniques implemented in the class to assess effectiveness in achieving the intended educational outcomes including improving student knowledge of material properties, behavior of structural members, load flow and connections, along with context in real-world structural engineering projects
Enhancing Telecom Churn Prediction: Adaboost with Oversampling and Recursive Feature Elimination Approach
Get PDFChurn prediction is a critical task for businesses to retain their valuable customers. This paper presents a comprehensive study of churn prediction in the telecom sector using 15 approaches, including popular algorithms such as Logistic Regression, Support Vector Machine, Decision Tree, Random Forest, and AdaBoost.
The study is segmented into three sets of experiments, each focusing on a different approach to building the churn prediction model. The model is constructed using the original training set in the first set of experiments. The second set involves oversampling the training set to address the issue of imbalanced data. Lastly, the third set combines oversampling with recursive feature selection to enhance the model\u27s performance further.
The results demonstrate that the Adaptive Boost classifier, implemented with oversampling and recursive feature selection, outperforms the other 14 techniques. It achieves the highest rank in all three evaluation metrics: recall (0.841), f1-score (0.655), and roc_auc (0.793), further indicating that the proposed approach effectively predicts churn and provides valuable insights into customer behavior
ANALYSIS OF SCRAMENTO STATE UNIVERSITY UNION
Get PDFSacramento State Union is a centrally located building with a large occupant load during the school year. This building is a 239,000-square-foot three-story structure built originally back in 1975. This original building was constructed using waffle slab construction. Additions in 1996 and 2016 were built using steel beam and girder construction to meet the total square footage we have today. This mixed-use occupancy is not only a congregation point, but many events are held in this building as well.
In this analysis of the building, fire life safety systems are reviewed and determined if they not only meet the minimum requirements set forth by the code but also do they allow for appropriate egress from design fires. The Structural fire protection was reviewed for appropriate rating on structural system like walls and ceilings as well as for the structural members. Fire Sprinkler and Fire Alarm systems were reviewed for appropriate space and calculations set forth by NFPA 13 and NFPA 72. Finally, the Egress was analyzed for occupant load and exit load on the floors, exit path and common path of travel. The analysis of all the prescriptive fire life safety systems proved to meet all code requirements.
Performance-based analysis was also done to review the required egress time for occupants to exit the building versus the allowed time determined from the design fires. The first design fire is located on the first floor in the dining center. This fire was selected due to its proximity to a major egress path that feeds both the first and second floor. The second design fire catches a wooden desk on fire in a small retail space, the fire then spreads to some surrounding clothing racks. Similar to the first, this design fires were selected due to its exposure to an egress path. The third design fire looked at how a large occupancy event could be impacted by a fire event. An electrical fire started a fire during a career fair event in the large multi-purpose room. This fire was analyzed as it travels down the room and spreads to more fuel load. The heat on the structure was also reviewed to see if any damage would occur. In all three design fires sprinkler activation was calculated using plume temperature calculations to operate at 100 seconds, 130 seconds, and 110 seconds using plume calculations and temperature of the upper plume. Through basic modeling using CFAST updated activation times were seen at 140 seconds and 50 seconds, no modeling was completed for the third design fire due to complexity. Two of the three scenarios showed a quicker activation of sprinklers than what was calculated by hand. The required egress time that was calculated was 144 seconds for the first floor. All fires had activation times prior to egress times. The tenability was also measured at activation and all design fires had Carbon Monoxide levels under the 1400 ppm requirement and temperatures under 60°C. The actual calculated RSET or required egress time for the design fires was 3 minutes and 24 seconds. With all three design fires having activation of sprinklers, it is assumed tenability would maintain and or increase as time increased, thus allowing for acceptable egress times. CFAST results show that for design fire 1 untenable conditions would not be reached until over 8 minutes after ignition. Design fire 2 results showed after 4 minutes conditions we exceed tenability requirements. Design fire three did not have CFAST results, but with limited fuel load and large open space an assumption can be made that tenability would remain high past RSET time. The results from this analysis of the building and its fire life safety systems show that all systems meet the minimum code requirements for the prescriptive designed system, as well as provide appropriate means of safety to adequately allow for egress according to the design fires that were presented. The only recommendation I would make to further help with fire life safety features is to install a smoke evacuation system at the skylight located in the center of the building. This would help to limit smoke exposure due to the open atrium between the first and second floor
Enriching the Story: Asexuality and Aromanticism in Literature
Get PDFThis paper examines the role of asexual and aromantic coding within Emily Brontë’s novel Wuthering Heights and Virginia Woolf’s novel To the Lighthouse. Both books utilize relationships and sexuality in order to portray arguments within the book. Brontë portrays Catherine and Heathcliff’s relationship as transcending physicality, both as a way to portray them as soulmates but also to foreshadow events. Woolf utilizes Lily’s disinterest in sex and marriage as a way to contrast her to other women in the novel. Both characterizations can be read as asexual, or in Lily’s case also aromantic. This queer reading allows insight into the characters but it also creates a characterization rarely seen in popular media or literature. It challenges social assumptions about sexuality and romance as well as heteronormative readings of literature. It gives the asexual and aromantic community a literary presence but also shows that the lack of representation can be damaging to the understanding and acceptance of asexual and aromantic individuals
A Woman Born Twice: Esther Greenwood’s Reconstruction of the Female Identity in a Pervasively Patriarchal 1950’s America
Get PDFCo-Simulation of Active Magnetic Bearing Rotors using Adams, MSC Apex, and Simulink
Get PDFApex-Adams-Simulink co-simulation is applied to active magnetic bearing (AMB) rotors, demonstrating results unshown in literature, including continuous frequency response, and unavailable in known rotor dynamics software, including touchdown bearing impact. AMBs levitate rotors without contact, so they involve no friction, wear, lubrication, pollution, or shaft speed limits and are thus valuable for large, high-speed applications. Modeling of such rotors, necessary for safety and performance, simultaneously requires flexible body dynamics and advanced control design, but simulation programs tend to specialize in only one or the other. The co-simulation method combines multiple such programs—MSC Apex (finite element modeling), Adams (multibody dynamics), and Simulink (graphical control design) with MATLAB (visualization tools)—expanding the design space for AMB rotor modeling beyond that of available commercial software. In this work, accuracy of co-simulation to theory is validated through a rigid AMB rotor and a hanging disk on a steel wire, and new results are shown for a flexible anisotropic rotor and a simplified touchdown bearing impact test