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2020

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Full-Text Articles in Engineering

Development Of A Process For Thermal And Mechanical Modelling Of Screw-Driven Pellets Extrusion, Kaixiang Shi Jan 2020

Development Of A Process For Thermal And Mechanical Modelling Of Screw-Driven Pellets Extrusion, Kaixiang Shi

Master’s Theses

The overall goal of the thesis project is to develop a process for thermal and mechanical modelling of the screw-driven pellets extrusion process, and applying the model results to design extruder temperature and flow rate controllers.

The proposed extruder is designed for metal 3D printing. The device demonstrates great potential in tackling some of the major issues faced by the metal additive manufacturing community. It eliminates the use of metal powder for workplace and workers safety. It is able to produce end-use parts with industrial grade mechanical and microstructural properties. It utilizes low cost metal-loaded polymer pellets as feedstock. However, …


The Artificial University: Decision Support For Universities In The Covid-19 Era, Wesley J. Wildman, Saikou Y. Diallo, George Hodulik, Andrew Page, Andreas Tolk, Neha Gondal Jan 2020

The Artificial University: Decision Support For Universities In The Covid-19 Era, Wesley J. Wildman, Saikou Y. Diallo, George Hodulik, Andrew Page, Andreas Tolk, Neha Gondal

VMASC Publications

Operating universities under pandemic conditions is a complex undertaking. The Artificial University (TAU) responds to this need. TAU is a configurable, open-source computer simulation of a university using a contact network based on publicly available information about university classes, residences, and activities. This study evaluates health outcomes for an array of interventions and testing protocols in an artificial university of 6,500 students, faculty, and staff. Findings suggest that physical distancing and centralized contact tracing are most effective at reducing infections, but there is a tipping point for compliance below which physical distancing is less effective. If student compliance is anything …


Evaluation Of 1-D And 2-D Hydraulic Models For Designing And Assessing Fullspan Stream Crossings, Alyssa Sachiko Virgil Jan 2020

Evaluation Of 1-D And 2-D Hydraulic Models For Designing And Assessing Fullspan Stream Crossings, Alyssa Sachiko Virgil

Cal Poly Humboldt theses and projects

This project compared design decisions and hydraulic analyses of full-span stream crossings using one- and two-dimensional (1-D and 2-D) hydraulic models. The project was initiated by the California Department of Transportation’s interest in moving from 1-D to 2-D hydraulic modeling and by the Federal Highways Administration’s support for adopting SRH-2D (Sedimentation and River Hydraulics-2D developed by the US Bureau of Reclamation) in Aquaveo, LLC’s Surface-water Modeling System as their standard design model. Two-dimensional hydraulic models calculate more detailed water depths and velocities than 1-D models, which can better identify fish passage conditions, areas of potential scour or deposition, and aquatic …


Sediment Yield In Salmon Creek After Decommissioning Logging Roads, Northern Humboldt County, California, Malia S B Gonzales Jan 2020

Sediment Yield In Salmon Creek After Decommissioning Logging Roads, Northern Humboldt County, California, Malia S B Gonzales

Cal Poly Humboldt theses and projects

Salmon Creek watershed is located in the Headwaters Forest Reserve in northern California and is known for the ecological value of its old-growth redwood forest, high biodiversity, and sensitive habitat for endangered species. The Bureau of Land Management primarily manages the Reserve. The land-use history of the Upper Salmon Creek watershed includes extensive timber harvest and road development. Watershed restoration in the Upper Salmon Creek watershed started in 2000 with the primary goal for the Reserve to protect and recover ecologic diversity and threatened native species. Since then, of the 23 miles, 13.5 miles of logging roads and 101 stream …


Multiple Criteria Decision-Making Approach To Support Timber Transportation Planning – Case Study In Brazil, Marinna Lopes Ferreira Gomes Jan 2020

Multiple Criteria Decision-Making Approach To Support Timber Transportation Planning – Case Study In Brazil, Marinna Lopes Ferreira Gomes

Cal Poly Humboldt theses and projects

Timber transportation is one of the costliest activities for a forest company in Brazil and in many other countries, and it is a determining factor for the success of the forest enterprise. Thus, decision support tools are commonly used as methods to reduce these costs. The purpose of this study was to develop and analyze mathematical models to define the weekly timber transport schedule based on the monthly demands of the customers. The goal is to minimize the operational costs of forest transportation related to distances, timber freshness and road qualities. The decision process was made in two steps; the …


Electrification Of Domestic Hot Water To Aid The Integration Of Renewable Energy In The California Grid, Alejandro Cervantes Jan 2020

Electrification Of Domestic Hot Water To Aid The Integration Of Renewable Energy In The California Grid, Alejandro Cervantes

Cal Poly Humboldt theses and projects

Water heating in residential buildings, also known as domestic hot water (DHW), is the third largest use of energy after appliances and space conditioning. About 90% of the residential buildings in the state use natural gas fueled water heaters, 6% use electricity, and a small percent use liquefied petroleum gas (LPG) or solar water heaters. The current energy use associated with residential water heating is small relative to the total amount of energy consumption in the residential building sector, but it is still a contributor of greenhouse gas (GHG) emissions. Improving hot water systems can be beneficial for bill customer …


Why Do I Have To Know This? Engineering In A Globalized Society, Caleb Cunningham Jan 2020

Why Do I Have To Know This? Engineering In A Globalized Society, Caleb Cunningham

Honors Theses

Through a pilot comparative study, this thesis examines the problem-solving of chemical engineering students and chemical engineering faculty. Specifically, the thesis examines the extent to which individuals include global factors (cultural, social, environmental, and economic) into their engineering solutions as specified by ABET. Several hypotheses were investigated in this pilot study: (i) having a study abroad experience would increase the likelihood that participants included the global factors of interest, (ii) the type (PUI, Research Intensive, Unique) of institution students attended would impact how individuals approached the problem, (iii) students with similar career aspirations would approach the problems similarly, (iv) having …


Landing Throttleable Hybrid Rockets With Hierarchical Reinforcement Learning In A Simulated Environment, Francesco Alessandro Stefano Mikulis-Borsoi Jan 2020

Landing Throttleable Hybrid Rockets With Hierarchical Reinforcement Learning In A Simulated Environment, Francesco Alessandro Stefano Mikulis-Borsoi

Honors Theses and Capstones

In this paper, I develop a hierarchical Markov Decision Process (MDP) structure for completing the task of vertical rocket landing. I start by covering the background of this problem, and formally defining its constraints. In order to reduce mistakes while formulating different MDPs, I define and develop the criteria for a standardized MDP definition format. I then decompose the problem into several sub-problems of vertical landing, namely velocity control and vertical stability control. By exploiting MDP coupling and symmetrical properties, I am able to significantly reduce the size of the state space compared to a unified MDP formulation. This paper …


Pfas Removals And Increases In The Effluent Of Thirteen New Hampshire Wastewater Treatment Facilities Due To The Effects Of Biological Treatment Processes, Zachary P. Harvell Jan 2020

Pfas Removals And Increases In The Effluent Of Thirteen New Hampshire Wastewater Treatment Facilities Due To The Effects Of Biological Treatment Processes, Zachary P. Harvell

Honors Theses and Capstones

PROPOSAL/ABSTRACT:

Perfluoroalkyl substances, or PFAS, are an emerging contaminant of concern in environmental engineering. This group of chemicals has been used by manufacturers since the 1940s due to their desirable waterproofing qualities. They also have a high chemical stability at high temperatures, which makes treatment difficult. A large variety of manufactured items contain PFAS, such as fabrics and apparel, non-stick items, and food wrappers. Recently, these compounds have come under question due to studies supporting harmful health effects, such as low birthweight, cancer, thyroid hormone disruption, and a weakened immune system. Due to their chemical structure, PFAS compounds are difficult …


A Review On Investigating The Experimental Process For Partial Replacement Of Cement With Sugarcane Bagasse In The Construction Industry, Amany G. Micheal Prof., Rania Rushdy Moussa Ass. Prof., Nadin Magdy Dawoud Eng. Jan 2020

A Review On Investigating The Experimental Process For Partial Replacement Of Cement With Sugarcane Bagasse In The Construction Industry, Amany G. Micheal Prof., Rania Rushdy Moussa Ass. Prof., Nadin Magdy Dawoud Eng.

Architectural Engineering

In the last few decades there has been speedily increasing in the agriculture and industrial wastes. This causes many environmental issues and raises the potential to contaminate the natural resources of living such as water, air and soil. Recently, the amount of organic waste produced daily has been rising, while it is poorly managed. It is either burned or disposed improperly, which effect negatively the environment and public health. On the other hand, during the cement production process many wastes, and pollutants are generated which have major negative impacts on the environment. Cement is considered as a substantial constituent of …


Progressive Collapse Assessment Of Post-Tensioned Reinforced Concrete Flat Slab Structures Using Aem, Amgad Mahrous, Mariam Ehab, Hamed Hadhoud Jan 2020

Progressive Collapse Assessment Of Post-Tensioned Reinforced Concrete Flat Slab Structures Using Aem, Amgad Mahrous, Mariam Ehab, Hamed Hadhoud

Civil Engineering

Progressive collapse is defined as the failure of a primary vertical element of a structure, which may result in the failure of adjoining elements, consequently, leads to a partial or total collapse of the structure. Unified Facilities Criteria (UFC) and General Services Administration (GSA) guidelines used to assess the behavior of structures subjected to progressive collapse as a result of the loss of primary vertical support. For the current case study, numerical analysis is carried out for a typical ten-story reinforced concrete post-tensioned flat slab structure subjected to primary vertical element loss (corner column, edge column, internal column, edge shear …


Indirect Thermosiphon Flat-Plate Solar Collector Performance Based On Twisted Tube Design Heat Exchanger Filled With Nanofluid, Mahmoud Eltaweel, Hazem Hussien, Ahmed A. Abdel-Rehim Jan 2020

Indirect Thermosiphon Flat-Plate Solar Collector Performance Based On Twisted Tube Design Heat Exchanger Filled With Nanofluid, Mahmoud Eltaweel, Hazem Hussien, Ahmed A. Abdel-Rehim

Mechanical Engineering

No abstract provided.


Energetic And Exergetic Analysis Of A Heat Pipe Evacuated Tube Solar Collector Using Mwcnt/Water Nanofluid, Mahmoud Eltaweel, Ahmed A. Abdel-Rehim Jan 2020

Energetic And Exergetic Analysis Of A Heat Pipe Evacuated Tube Solar Collector Using Mwcnt/Water Nanofluid, Mahmoud Eltaweel, Ahmed A. Abdel-Rehim

Mechanical Engineering

Increasing the energy demand and the limited availability of conventional energy sources are the main challenges to secure the human future. Solar energy is an attractive source of energy to ensure the sustainability of energy in this world for now and for the future. Evacuated tube solar collector is a solar thermal collector mostly used for domestic applications. The replacement of the working fluid with nanofluid can enhance the heat transfer even for low temperature applications. The effect of multi-walled carbon nanotubes and water nanofluid as working fluid in evacuated tube solar collector is used to experimentally investigate the energy …


Application Of Decline Curve Analysis To Unconventional Reservoir, Ahmed Wasel Alqattan Jan 2020

Application Of Decline Curve Analysis To Unconventional Reservoir, Ahmed Wasel Alqattan

Graduate Theses, Dissertations, and Problem Reports (ETD)

The oil and gas industry has been dealing with the unconventional reservoirs for about only two decades. Consequently, many challenges remain in evaluating the unconventional reservoirs. A few of these obstacles are the absence of the adequate production history, understanding the fluid flow regime after hydraulic fracturing, and estimating the drainage volume of the reservoir. One of the essential elements for evaluation of the oil and reservoir is to estimate the production rates over time in order to investigate the economic potential of the project.

Decline Curve Analysis (DCA) is most common the methodology for predicting the production rates over …


The Impact Of Stress Shadowing With Variations In Cluster Spacing On The Production For Wells Completed In The Marcellus Shale, Joshua R. Dietz Jan 2020

The Impact Of Stress Shadowing With Variations In Cluster Spacing On The Production For Wells Completed In The Marcellus Shale, Joshua R. Dietz

Graduate Theses, Dissertations, and Problem Reports (ETD)

The design of the well stimulation treatment has significantly changed over the last decade because of the advancement of hydraulic fracturing. The cluster and stage spacing design component of hydraulic fracturing has been a key factor in enhancing the production from the horizontal wells. Recently, the treatment designs are moving towards lower cluster spacing. The reduction of the spacing alters the in-situ stresses in the formation and begin to impact the propagation of next set of future fractures and the properties of previous fractures. These stress alterations from hydraulic fracturing is referred to as stress shadowing.

The objective of study …


Automatic Chest X-Rays Analysis Using Statistical Machine Learning Strategies, Hermann Yepdjio Nkouanga Jan 2020

Automatic Chest X-Rays Analysis Using Statistical Machine Learning Strategies, Hermann Yepdjio Nkouanga

All Master's Theses

Tuberculosis (TB) is a disease responsible for the deaths of more than one million people worldwide every year. Even though it is preventable and curable, it remains a major threat to humanity that needs to be taken care of. It is often diagnosed in developed countries using approaches such as sputum smear microscopy and culture methods. However, since these approaches are rather expensive, they are not commonly used in poor regions of the globe such as India, Africa, and Bangladesh. Instead, the well known and affordable chest x-ray (CXR) interpretation by radiologists is the technique employed in those places. Nevertheless, …


Site-Specific Irrigation Management In A Sub-Humid Climate Using A Spatial Evapotranspiration Model With Satellite And Airborne Imagery, Sandeep Bhatti, Derek M. Heeren, J. Burdette Barker, Christopher M. U. Neale, Wayne Woldt, Mitchell S. Maguire, Daran Rudnick Jan 2020

Site-Specific Irrigation Management In A Sub-Humid Climate Using A Spatial Evapotranspiration Model With Satellite And Airborne Imagery, Sandeep Bhatti, Derek M. Heeren, J. Burdette Barker, Christopher M. U. Neale, Wayne Woldt, Mitchell S. Maguire, Daran Rudnick

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Variable Rate Irrigation (VRI) considers spatial variability in soil and plant characteristics to optimize irrigation management in agricultural fields. The advent of unmanned aircraft systems (UAS) creates an opportunity to utilize high-resolution (spatial and temporal) imagery into irrigation management due to decreasing costs, ease of operation, and reduction of regulatory constraints. This research aimed to evaluate the use of UAS data for VRI, and to quantify the potential of VRI in terms of relative crop and water response. Irrigation treatments were: (1) VRI using Landsat imagery (VRI-L), (2) VRI using UAS imagery (VRI-U), (3) uniform (U), and (4) rainfed (R). …


An Automated Seepage Meter For Streams And Lakes, D. Kip Solomon, Eric Humphrey, Troy E. Gilmore, David P. Genereux, Vitaly Zlotnik Jan 2020

An Automated Seepage Meter For Streams And Lakes, D. Kip Solomon, Eric Humphrey, Troy E. Gilmore, David P. Genereux, Vitaly Zlotnik

Department of Agricultural and Biological Systems Engineering: Faculty Publications

We describe a new automatic seepage meter for use in soft bottom streams and lakes. The meter utilizes a thin‐walled tube that is inserted into the streambed or lakebed. A hole in the side of the tube is fitted with an electric valve. Prior to the test, the valve is open and the water level inside the tube is the same as the water level outside the tube. The test starts with closure of the valve, and the water level inside the tube changes as it moves toward the equilibrium hydraulic head that exists at the bottom of the tube. …


Automatic Wheat Lodging Detection And Mapping In Aerial Imagery To Support High-Throughput Phenotyping And In-Season Crop Management, Biquan Zhao, Jiating Li, P. Stephen Baenziger, Vikas Belamkar, Yufeng Ge, Jian Zhang, Yeyin Shi Jan 2020

Automatic Wheat Lodging Detection And Mapping In Aerial Imagery To Support High-Throughput Phenotyping And In-Season Crop Management, Biquan Zhao, Jiating Li, P. Stephen Baenziger, Vikas Belamkar, Yufeng Ge, Jian Zhang, Yeyin Shi

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Latest advances in unmanned aerial vehicle (UAV) technology and convolutional neural networks (CNNs) allow us to detect crop lodging in a more precise and accurate way. However, the performance and generalization of a model capable of detecting lodging when the plants may show different spectral and morphological signatures have not been investigated much. This study investigated and compared the performance of models trained using aerial imagery collected at two growth stages of winter wheat with different canopy phenotypes. Specifically, three CNN-based models were trained with aerial imagery collected at early grain filling stage only, at physiological maturity only, and at …


Two-Stage Deep Learning Architecture For Pneumonia Detection And Its Diagnosis In Chest Radiographs, Barath Narayanan, Venkata Salini Priyamvada Davuluru, Russell C. Hardie Jan 2020

Two-Stage Deep Learning Architecture For Pneumonia Detection And Its Diagnosis In Chest Radiographs, Barath Narayanan, Venkata Salini Priyamvada Davuluru, Russell C. Hardie

Electrical and Computer Engineering Faculty Publications

Approximately two million pediatric deaths occur every year due to Pneumonia. Detection and diagnosis of Pneumonia plays an important role in reducing these deaths. Chest radiography is one of the most commonly used modalities to detect pneumonia. In this paper, we propose a novel two-stage deep learning architecture to detect pneumonia and classify its type in chest radiographs. This architecture contains one network to classify images as either normal or pneumonic, and another deep learning network to classify the type as either bacterial or viral. In this paper, we study and compare the performance of various stage one networks such …


Glaciernet: A Deep-Learning Approach For Debris-Covered Glacier Mapping, Zhiyuan Xie, Umesh K. Haritashya, Vijayan K. Asari, Brennan W. Young, Michael P. Bishop, Jeffrey S. Kargel Jan 2020

Glaciernet: A Deep-Learning Approach For Debris-Covered Glacier Mapping, Zhiyuan Xie, Umesh K. Haritashya, Vijayan K. Asari, Brennan W. Young, Michael P. Bishop, Jeffrey S. Kargel

Electrical and Computer Engineering Faculty Publications

Rising global temperatures over the past decades is directly affecting glacier dynamics. To understand glacier fluctuations and document regional glacier-state trends, glacier-boundary detection is necessary. Debris-covered glacier (DCG) mapping, however, is notoriously difficult using conventional geospatial technology methods. Therefore, in this research for automated DCG mapping, we evaluate the utility of a convolutional neural network (CNN), which is a deep learning feed-forward neural network. The CNN inputs include Landsat satellite images, an Advanced Land Observation Satellite (ALOS) digital elevation model (DEM) and DEM-derived land-surface parameters. Our CNN based deep-learning approach named GlacierNet was designed by appropriately choosing the type, number …


Mitosisnet: End-To-End Mitotic Cell Detection By Multi-Task Learning, Md Zahangir Alom, Theus Aspiras, Tarek M. Taha, Tj Bowen, Vijayan K. Asari Jan 2020

Mitosisnet: End-To-End Mitotic Cell Detection By Multi-Task Learning, Md Zahangir Alom, Theus Aspiras, Tarek M. Taha, Tj Bowen, Vijayan K. Asari

Electrical and Computer Engineering Faculty Publications

Mitotic cell detection is one of the challenging problems in the field of computational pathology. Currently, mitotic cell detection and counting are one of the strongest prognostic markers for breast cancer diagnosis. The clinical visual inspection on histology slides is tedious, error prone, and time consuming for the pathologist. Thus, automatic mitotic cell detection approaches are highly demanded in clinical practice. In this paper, we propose an end-to-end multi-task learning system for mitosis detection from pathological images which is named"MitosisNet". MitosisNet consist of segmentation, detection, and classification models where the segmentation, and detection models are used for mitosis reference region …


A Relook At Canada’S Western Canada Sedimentary Basin For Power Generation And Direct-Use Energy Production, Catherine Hickson, Katie Huang, Darrell Cotterill, Will Gosnold, Dick Benoit Jan 2020

A Relook At Canada’S Western Canada Sedimentary Basin For Power Generation And Direct-Use Energy Production, Catherine Hickson, Katie Huang, Darrell Cotterill, Will Gosnold, Dick Benoit

Geology and Geological Engineering Faculty Publications

The Alberta No. 1 Project, under the terms of Canada’s Federal government’s Emerging Renewable Power Program (ERPP), must produce 5MWe net. The goal of this study was to identify areas where three essential constraining conditions overlap; (1) the temperature gradient is sufficiently high that 120°C brines at depths of 4,500m or less are potentially available, (2) there are formations at the depths targeted with known high fluid flows, and (3) there is adequate existing infrastructure that supports low-cost power grid connection as well as a direct use application. A fluid temperature of at least 120oC is needed to …


Comparative Scoping Study Report For The Extraction Of Microalgae Oils From Two Subspecies Of Chlorella Vulgaris, Jasmine Kreft, Eric Moe, Nicholas Garcia, Andrew Ross, Wayne Seames Jan 2020

Comparative Scoping Study Report For The Extraction Of Microalgae Oils From Two Subspecies Of Chlorella Vulgaris, Jasmine Kreft, Eric Moe, Nicholas Garcia, Andrew Ross, Wayne Seames

Chemistry Faculty Publications

The production of microalgae as a fatty acid oil resource for use in biofuels production is a widespread research topic at the lab scale. Microalgae contain a higher lipid content on a dry-weight basis compared to oilseeds such as soybeans. Additionally, the growth and cultivation cycle of microalgae is 15 days, in comparison to soybeans, for which the cycle occurs once or twice annually. However, to date, it has been uneconomical to produce microalgae oils in a world-scale facility due to limitations in cultivating microalgae at commercial scales. Recent developments suggest that the use of heterotrophic microalgae may be economically …


Rapid Orbital Motion Emulator (Rome): Kinematics Modeling And Control, Ahmed Elsadek Ahmed Seleit Jan 2020

Rapid Orbital Motion Emulator (Rome): Kinematics Modeling And Control, Ahmed Elsadek Ahmed Seleit

Electronic Theses and Dissertations, 2020-2023

Space missions design requires already tested and trusted control algorithms for spacecraft motion. Rapidly testing control algorithms at a low cost is essential. A novel robotic system that emulates orbital motion in a laboratory environment is presented. The system is composed of a six degree of freedom robotic manipulator fixed on top of an omnidirectional ground vehicle accompanied with onboard computer and sensors. The integrated mobile manipulator is used as a testbed to emulate and realize orbital motion and control algorithms. The kinematic relations of the ground vehicle, robotic manipulator and the coupled kinematics are derived. The system is used …


Emulsion Characterization Study For Improved Bilgewater Treatment And Management, Daniela Diaz Hernandez Jan 2020

Emulsion Characterization Study For Improved Bilgewater Treatment And Management, Daniela Diaz Hernandez

Electronic Theses and Dissertations, 2020-2023

The need for proper management of bilgewater to meet discharge regulations (e.g., 15 ppm oil) has revealed the necessity to expand the current understanding of bilgewater emulsions. This study proposed to evaluate emulsion stability under various environmental conditions and to identify governing parameters for emulsion formation. The stabilizing properties of eight-commercial cleaners and two-neat surfactants were evaluated. In situ characterization techniques were used for monitoring emulsion stability. Additionally, a needle-type pH microsensor and fluorescence spectroscopy were used for analyzing mass transfer at the oil-water interface. Water quality of extracted bilgewater showed to highly vary between vessels (e.g., conductivity: 1.74 -- …


An Investigation Of Life Cycle Sustainability Implications Of Emerging Heavy-Duty Truck Technologies In The Age Of Autonomy, Burak Sen Jan 2020

An Investigation Of Life Cycle Sustainability Implications Of Emerging Heavy-Duty Truck Technologies In The Age Of Autonomy, Burak Sen

Electronic Theses and Dissertations, 2020-2023

Heavy-duty trucks (HDTs) play a central role in U.S. freight transportation, carrying most of the goods across the country. The projected increase in freight activity (e.g. truck-miles-traveled) raises concerns regarding the potential sustainability impacts of the U.S. freight industry, marking HDTs as an ideal domain for improving the sustainability performance of U.S. freight transportation. However, the transition to sustainable trucking is a challenging task, for which multiple sustainability objectives must be considered and addressed under a variety of emerging HDT technologies while composing a sustainable HDT fleet. To gain insights into the sustainability implications of emerging HDT technologies as well …


Saperi: Approaching Gender Gap Using Spatial Ability Training Week In High-School Context, Maria Giulia Ballatore, Gavin Duffy, Sheryl Sorby, Anita Tabacco Jan 2020

Saperi: Approaching Gender Gap Using Spatial Ability Training Week In High-School Context, Maria Giulia Ballatore, Gavin Duffy, Sheryl Sorby, Anita Tabacco

Conference papers

The purpose of this paper is to describe the structure of a girls summer school, “SAperI – Spatial Ability per l’Ingegneria” (in English, “Knowledge – Spatial Ability for Engineering”), and to illustrate its impact on spatial ability development and future career preferences on those who participated in the week long summer school compared to a control group that did not participate.The 5 days school,
organized by Politecnico di Torino (Italy), was included in a larger project addressing 17 years old high-school students. Thirtyseven girls actively took part in a summer school, while 167 students (both males and females) were tested …


การปรับปรุงสะพานทางหลวงจากผลกระทบแผ่นดินไหวด้วยระบบแยกฐานและการเสริมค่าความหน่วงโดยใช้เหล็กเดือย, ยงศักดิ์ จิวะตระกูลธรรม Jan 2020

การปรับปรุงสะพานทางหลวงจากผลกระทบแผ่นดินไหวด้วยระบบแยกฐานและการเสริมค่าความหน่วงโดยใช้เหล็กเดือย, ยงศักดิ์ จิวะตระกูลธรรม

Chulalongkorn University Theses and Dissertations (Chula ETD)

การออกแบบโครงสร้างสะพานภายใต้แรงแผ่นดินไหวด้วยระบบแยกฐาน สามารถลดผลกระทบที่เกิดจากแรงกระทำได้เป็นอย่างดี แต่ในขณะเดียวกันกลับทำให้โครงสร้างสะพานส่วนบนเกิดการเคลื่อนตัวที่มากขึ้นเป็นผลให้เกิดการชนกันระหว่างชิ้นส่วน และเกิดการวิบัติจากระยะรองรับช่วงสะพานที่ไม่เพียงพอ งานวิจัยนี้มีวัตถุประสงค์ในการศึกษาผลตอบสนองของชิ้นส่วนโครงสร้างสะพานที่ถูกออกแบบด้วยระบบแยกฐานและใช้เหล็กเดือยช่วยในการสลายพลังงานและลดการเคลื่อนที่ของคาน ซึ่งจะทำการวิเคราะห์โครงสร้างด้วยวิธีการไฟไนต์อิลิเมนต์ โดยใช้โปรแกรม SAP2000 การศึกษาเลือกพิจารณาสะพานแบบคานคอนกรีตอัดแรงรูปตัวไอ มีความยาวช่วงเสา 20 เมตร ทั้งหมด 5 ช่วง มีการติดตั้งแผ่นยางรองคานสะพานเป็นอุปกรณ์แยกฐาน นอกจากนี้จะทำการคัดเลือกคลื่นแผ่นดินไหวให้สอดคล้องกับการสั่นไหวของพื้นดินที่เกิดขึ้นใน จังหวัดเชียงใหม่ ประเทศไทย หลังจากทำการสร้างแบบจำลองจะทำการวิเคราะห์โครงสร้างด้วยวิธีการวิเคราะห์การตอบสนองไม่เชิงเส้นแบบประวัติเวลา โดยจะทำการเปรียบเทียบผลการตอบสนองของโครงสร้างสะพานทั้งก่อนและหลังการปรับปรุงโดยใช้เหล็กเดือย ซึ่งจะพิจารณาในกรณีที่เพิ่มความหนาของแผ่นยางรองคานสะพานจากเดิมขนาด 20 เป็น 100 มิลลิเมตร และทำการติดตั้งเหล็กเดือยขนาดเส้นผ่านศูนย์กลาง 25 มิลลิเมตร เป็นอุปกรณ์ยึดรั้ง ผลการศึกษาพบว่าการเลือกปรับปรุงโดยการเลือกใช้เหล็กเดือยจำนวน 2 ชิ้น ติดตั้งในระนาบที่ยึดรั้งบริเวณจุดรองรับของโครงสร้างสะพานส่วนบนกับโครงสร้างสะพานส่วนล่าง ให้ผลการตอบสนองที่เหมาะสมมากกว่ากรณีก่อนการปรับปรุง โดยระยะการเคลื่อนตัวสูงสุดของคานรองรับแผ่นพื้นลดลงจาก 64 เป็น 51 มิลลิเมตร คิดเป็นร้อยละ 20 และยังช่วยลดผลการตอบสนองของโครงสร้างสะพานส่วนล่าง โดยเสาตอม่อเกิดการครากเพียงเล็กน้อย นอกจากนี้แรงเฉือนสูงสุดที่ฐานลดลงร้อยละ 22 เมื่อเทียบกับกรณีก่อนการปรับปรุงโครงสร้างสะพาน


การพัฒนาผนังสลายพลังงานแบบวิสโคอิลาสติก, ฐิติพงศ์ เจริญสุข Jan 2020

การพัฒนาผนังสลายพลังงานแบบวิสโคอิลาสติก, ฐิติพงศ์ เจริญสุข

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์ในการศึกษาพัฒนาผนังสลายพลังงานแบบวิสโคอิลาสติก (Viscoelastic wall dampers) ด้วยวัสดุ Asphalt (ยางมะตอย) และ Polyisobutene (PIB) แม้ว่าในปัจจุบันมีผู้ผลิตอุปกรณ์สลายพลังงานสำหรับอาคารเพื่อต้านทานแผ่นดินไหวและแรงลมจำหน่าย แต่มีราคาแพงเพราะต้องนำเข้าจากต่างประเทศ ทั้งมีค่าใช้จ่ายในการติดตั้งและบำรุงรักษาที่สูง นอกจากนั้นยังพบว่า ส่วนใหญ่มีรูปแบบที่กระทบต่อความสวยงามด้านสถาปัตยกรรม ในงานวิจัยนี้จึงพิจารณาถึงความเป็นไปได้ในการพัฒนาผนังสลายพลังงานแบบวิสโคอิลาสติกด้วยวัสดุที่มีราคาไม่แพง มีรูปแบบคล้ายผนังอาคารทั่วไปเพื่อไม่กระทบต่อความสวยงามของอาคาร โดยทำการพัฒนาแบบจำลองทางคณิตศาสตร์ของผนังสลายพลังงานจากการทดสอบชิ้นงานตัวอย่างขนาดย่อส่วนในห้องปฏิบัติการ ภายใต้แรงกระทำแบบวัฏจักร (Cyclic testing) ตามมาตรฐาน ASCE 7-16 ผลการทดลองแสดงให้เห็นว่าวัสดุ PIB มีคุณสมบัติในการสลายพลังงานที่ดี และมีเสถียรภาพภายใต้การเปลี่ยนแปลงอุณหภูมิ จึงนำแบบจำลองทางคณิตศาสตร์ของผนังสลายพลังงานชนิด PIB มาประมาณคุณสมบัติของผนังสลายพลังงานขนาดเท่าของจริง เพื่อเปรียบเทียบประสิทธิภาพในการสลายพลังงานกับผลิตภัณฑ์ผนังสลายพลังงานแบบหนืด (Viscous Wall Damper) ของต่างประเทศ ผลการศึกษาพบว่าผนังสลายพลังงานแบบวิสโคอิลาสติคที่พัฒนามีประสิทธิภาพในการสลายพลังงานดีกว่าผนังสลายพลังงานแบบหนืดอย่างมีนัยสำคัญ ทำให้สามารถลดขนาดและจำนวนผนังสลายพลังงานที่ต้องติดตั้งในอาคารได้ จึงเป็นอีกหนึ่งทางเลือกในการออกแบบต้านทานแผ่นดินไหวและแรงลมที่อาจประหยัดและมีประสิทธิภาพกว่าวิธีการปกติที่นิยมเพิ่มขนาดส่วนโครงสร้างให้มีกำลังหรือสติฟเนสมากขึ้น