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San Jose State University

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2013

Articles 1 - 24 of 24

Full-Text Articles in Engineering

Loading Path Determination For Tube Hydroforming Process Of Automotive Component Using Apdl, E. Masoumi Khalil Abad, Amir Ghazanfari, R. Hashemi Dec 2013

Loading Path Determination For Tube Hydroforming Process Of Automotive Component Using Apdl, E. Masoumi Khalil Abad, Amir Ghazanfari, R. Hashemi

Faculty Publications, Mechanical Engineering

In this study, an extended stress-based forming limit diagram (FLD) for prediction of necking based on the Marciniak and Kucznski (M-K) model is represented and applied in tube hydroforming. The bulge forming of a straight tube is simulated by finite element method and verified with published experimental data. This adaptive simulation technique is based on the ability to detect the onset and growth of defects (e.g., bursting and wrinkling) and to promptly readjust the loading paths. Thus, a suitable load path is determined by applying Adaptive Simulation Method in ANSYS Parametric Design Language (APDL).


In-Situ Study Of E-Beam Al And Hf Metal Deposition On Native Oxide Inp (100), H. Dong, Santosh Kc, A. Azcatl, W. Cabrera, X. Qin, B. Brennan, D. Zhernokletov, K. Cho, R. Wallace Nov 2013

In-Situ Study Of E-Beam Al And Hf Metal Deposition On Native Oxide Inp (100), H. Dong, Santosh Kc, A. Azcatl, W. Cabrera, X. Qin, B. Brennan, D. Zhernokletov, K. Cho, R. Wallace

Faculty Publications

The interfacial chemistry of thin Al (∼3 nm) and Hf (∼2 nm) metal films deposited by electron beam (e-beam) evaporation on native oxide InP (100) samples at room temperature and after annealing has been studied by in situ angle resolved X-ray photoelectron spectroscopy and low energy ion scattering spectroscopy. The In-oxides are completely scavenged forming In-In/In-(Al/Hf) bonding after Al and Hf metal deposition. The P-oxide concentration is significantly decreased, and the P-oxide chemical states have been changed to more P-rich oxides upon metal deposition. Indium diffusion through these metals before and after annealing at 250 °C has also been characterized. …


Biologically Enhanced Cathode Design For Improved Capacity And Cycle Life For Lithium-Oxygen Batteries, Dahyun Oh, Jifa Qi, Yi-Chun Lu, Yong Zhang, Yang Shao-Horn, Angela Belcher Nov 2013

Biologically Enhanced Cathode Design For Improved Capacity And Cycle Life For Lithium-Oxygen Batteries, Dahyun Oh, Jifa Qi, Yi-Chun Lu, Yong Zhang, Yang Shao-Horn, Angela Belcher

Faculty Publications

Lithium-oxygen batteries have a great potential to enhance the gravimetric energy density of fully packaged batteries by two to three times that of lithium ion cells. Recent studies have focused on finding stable electrolytes to address poor cycling capability and improve practical limitations of current lithium-oxygen batteries. In this study, the catalyst electrode, where discharge products are deposited and decomposed, was investigated as it has a critical role in the operation of rechargeable lithium-oxygen batteries. Here we report the electrode design principle to improve specific capacity and cycling performance of lithium-oxygen batteries by utilizing high-efficiency nanocatalysts assembled by M13 virus …


Mammalian Cells Preferentially Internalize Hydrogel Nanodiscs Over Nanorods And Use Shape-Specific Uptake Mechanisms, Rachit Agarwal, Vikramjit Singh, Patrick Jurney, Li Shi, S. Sreenivasan, Krishnendu Roy Oct 2013

Mammalian Cells Preferentially Internalize Hydrogel Nanodiscs Over Nanorods And Use Shape-Specific Uptake Mechanisms, Rachit Agarwal, Vikramjit Singh, Patrick Jurney, Li Shi, S. Sreenivasan, Krishnendu Roy

Faculty Publications

Size, surface charge, and material compositions are known to influence cell uptake of nanoparticles. However, the effect of particle geometry, i.e., the interplay between nanoscale shape and size, is less understood. Here we show that when shape is decoupled from volume, charge, and material composition, under typical in vitro conditions, mammalian epithelial and immune cells preferentially internalize disc-shaped, negatively charged hydrophilic nanoparticles of high aspect ratios compared with nanorods and lower aspect-ratio nanodiscs. Endothelial cells also prefer nanodiscs, however those of intermediate aspect ratio. Interestingly, unlike nanospheres, larger-sized hydrogel nanodiscs and nanorods are internalized more efficiently than their smallest counterparts. …


In Situ Study Of The Role Of Substrate Temperature During Atomic Layer Deposition Of Hfo2 On Inp, H. Dong, Santosh Kc, X. Qin, B. Brennan, S. Mcdonnell, D. Zhernokletov, C. Hinkle, J. Kim, K. Cho, R. Wallace Oct 2013

In Situ Study Of The Role Of Substrate Temperature During Atomic Layer Deposition Of Hfo2 On Inp, H. Dong, Santosh Kc, X. Qin, B. Brennan, S. Mcdonnell, D. Zhernokletov, C. Hinkle, J. Kim, K. Cho, R. Wallace

Faculty Publications

The dependence of the “self cleaning” effect of the substrate oxides on substrate temperature during atomic layer deposition (ALD) of HfO2 on various chemically treated and native oxide InP (100) substrates is investigated using in situ X-ray photoelectron spectroscopy. The removal of In-oxide is found to be more efficient at higher ALD temperatures. The P oxidation states on native oxide and acid etched samples are seen to change, with the total P-oxide concentration remaining constant, after 10 cycles of ALD HfO2 at different temperatures. An (NH4)2 S treatment is seen to effectively remove native oxides and passivate the InP surfaces …


On The Primitives Of Causality: From The Semantics Of Agonist And Antagonist To Models Of Accident Causation And System Safety, Loïc Brevault, Francesca Favaro, Joseph Saleh Sep 2013

On The Primitives Of Causality: From The Semantics Of Agonist And Antagonist To Models Of Accident Causation And System Safety, Loïc Brevault, Francesca Favaro, Joseph Saleh

Faculty Publications

Controversial discussions on causality have been present in ancient philosophy since the days of Aristotle. Despite the use of this concept in numerous subjects, there is no consensus on the definition of causality and its possible mathematization. Many authors have analyzed the relation between causes and effects; the predominant school of thought reduces causation to a physical relation (either deterministic or probabilistic) between two events. The distinction between causes and consequences is not always clear and meaningful as different “layers of understanding” may be applied to the notion of causality. From this point of view the cause-effect implication relation can …


Indium Diffusion Through High-K Dielectrics In High-K/Inp Stacks, H. Dong, W. Cabrera, R. Galatage, Santosh Kc, B. Brennan, X. Qin, S. Mcdonnell, D. Zhernokletov, C. Hinkle, K. Cho, Y. Chabal, R. Wallace Aug 2013

Indium Diffusion Through High-K Dielectrics In High-K/Inp Stacks, H. Dong, W. Cabrera, R. Galatage, Santosh Kc, B. Brennan, X. Qin, S. Mcdonnell, D. Zhernokletov, C. Hinkle, K. Cho, Y. Chabal, R. Wallace

Faculty Publications

Evidence of indium diffusion through high-k dielectric (Al2O3 and HfO2) films grown on InP (100) by atomic layer deposition is observed by angle resolved X-ray photoelectron spectroscopy and low energy ion scattering spectroscopy. The analysis establishes that In-out diffusion occurs and results in the formation of a POx rich interface.High mobility III-V channel materials are contenders to replace Si in semiconductor devices like metal oxide semiconductor filed effect transistors (MOSFETs) for the sub 22 nm technology node.1 Extensive research is being carried out to determine the validity of these III-V materials for use as the channel, in a variety of …


Public Works For Public Learning: A Case Study, Thalia Anagnos, Beckey Carroll, Shannon Weiss, David Heil Jun 2013

Public Works For Public Learning: A Case Study, Thalia Anagnos, Beckey Carroll, Shannon Weiss, David Heil

Faculty Publications

Large scale and small scale public works projects are important in the smooth operation of every community, yet a majority of the population has little awareness of how these projects work and what their functions are. Few non-engineers understand the engineering challenges of delivering clean water, disposing of our sewage, or changing a traditional intersection into a round-about, a project that seems quite simple on the surface. A consortium of public works engineers, science museums, faculty, and exhibit evaluators were awarded a grant by the National Science Foundation to build an outdoor museum next to a large suspension bridge. The …


Curriculum Exchange: “Make Your Own Earthquake”, Sandra Seale, Thalia Anagnos, Lelli Van Den Einde Jun 2013

Curriculum Exchange: “Make Your Own Earthquake”, Sandra Seale, Thalia Anagnos, Lelli Van Den Einde

Faculty Publications

A consortium of American universities is involved in earthquake engineering practice and research. Each campus of the consortium participates in outreach and education activities for the local schools and the public. One campus of the consortium, which operates earthquake field sites, designed a K-12 activity called “Make Your Own Earthquake” (MYOE). MYOE involves setting up earthquake field equipment (seismic instruments, data loggers, and computers) in a classroom. Children jump for 10 seconds, see their earthquake trace live on a computer screen and then take home a printed copy of their personal earthquake. Software was developed specifically for this activity. MYOE …


Public Works Projects As Vehicles For Engineering Education And Outreach, Shannon Weiss, David Heil, Thalia Anagnos Jun 2013

Public Works Projects As Vehicles For Engineering Education And Outreach, Shannon Weiss, David Heil, Thalia Anagnos

Faculty Publications

America is built on small and large feats of public works engineering that, although often taken for granted, affect almost every aspect of our daily lives. So how can we celebrate these marvels of utilitarian infrastructure and use them to teach public audiences about the engineering principles, materials, and human innovations that make them possible? This case study will share how one project addressed these questions by leveraging informal learning strategies, multi-agency collaborations, and new media technologies to explain the history and engineering of one of the world’s most recognizable public work sites: the Golden Gate Bridge. This paper will …


Curriculum Exchange: Visualization Tools And Online Courses For Teaching About Earthquakes, Sandra Seale, Thalia Anagnos Jun 2013

Curriculum Exchange: Visualization Tools And Online Courses For Teaching About Earthquakes, Sandra Seale, Thalia Anagnos

Faculty Publications

As part of a national consortium of universities practicing and doing research in earthquake engineering, our site has developed several videos for use in outreach and education. Visualization tools are extremely useful when teaching about how earthquakes shake the ground and the response of buildings to that shaking. Here we present videos that are targeted to specific audiences: (1) Animations of the response of two model buildings to two earthquakes are targeted at grade 6-16 students. The videos were created with data recorded on these test structures from the two earthquakes. The two events were both located directly below the …


Exceed: Excellence In Your Engineering Education Summer Transition Program, Stacy Gleixner, Katherine Casey, Jared Tuberty, S. Latic, Patricia Backer, Emily Allen Jun 2013

Exceed: Excellence In Your Engineering Education Summer Transition Program, Stacy Gleixner, Katherine Casey, Jared Tuberty, S. Latic, Patricia Backer, Emily Allen

Faculty Publications

EXCEED: Excellence in Your Engineering Education is a ten day, residential summer transition program that was designed to improve retention and graduation rates at San José State University (SJSU). SJSU is a large, public institution in the West with a very diverse student population. However, the university has lower graduation and retention rates for certain student populations in engineering including underrepresented groups and first generation college students. This transition program was designed to meet five outcomes: acculturate the students to the College of Engineering and the university, enhance math and writing preparation, build community amongst the cohort of students, enhance …


How Important Is The Wow Factor In First Year Engineering Courses?, Thalia Anagnos, Burford Furman, Ping Hsu, Patricia Backer Jun 2013

How Important Is The Wow Factor In First Year Engineering Courses?, Thalia Anagnos, Burford Furman, Ping Hsu, Patricia Backer

Faculty Publications

This paper discusses the effectiveness of using projects with a “wow factor,” that is, engaging and challenging hands-on projects, in a freshman engineering course to motivate studentretention and persistence in engineering. Our course enrolls approximately 700 students per year in a lecture/laboratory format. Our university, a large comprehensive public university in thewest, has offered a freshman introduction to engineering course since 1992. In its original form, the course was part of a lower division engineering core, required of all engineering majors, and focused on computational skills (spreadsheets and MATLAB).In 1997, based on faculty and student feedback, a task force was …


Connecting Design Problem Characteristics To Prototyping Choices To Form A Prototyping Strategy, Bradley Camburn, Brock Dunlap, Vimal Viswanathan, Julie Linsey, Daniel Jensen, Richard Crawford, Kevin Otto, Kristin Wood Jun 2013

Connecting Design Problem Characteristics To Prototyping Choices To Form A Prototyping Strategy, Bradley Camburn, Brock Dunlap, Vimal Viswanathan, Julie Linsey, Daniel Jensen, Richard Crawford, Kevin Otto, Kristin Wood

Faculty Publications, Mechanical Engineering

Connecting Design Problem Characteristics to Prototyping Choices to Form a Prototyping Strategy Abstract Prototyping is a critical part of the product design process with the potential to play a significant role in determining the success or failure of the product. A variety of decisions are made by the design team when determining the manner in which they will develop prototypes. Example decisions include: choosing to develop either multiple prototypes or only a single prototype; and choosing to develop either a scaled or fully functional prototype. We define a prototyping strategy as the compilation of all the decisions that need to …


Training Future Designers: A Study On The Role Of Physical Models, Vimal Viswanathan, Julie Linsey Jun 2013

Training Future Designers: A Study On The Role Of Physical Models, Vimal Viswanathan, Julie Linsey

Faculty Publications, Mechanical Engineering

Physical Models in Engineering Education: Making Tomorrow’s Designers Creative Innovation and creativity are two essential qualities for tomorrow’s designers. In order to nurture these skills in designers, our engineering curricula need to include more hands-on training. In recent times, many engineering educators have recognized the importance of hands-on training in engineering curriculum. Allowing students to build and test their own physical models and learn from their mistakes can be a very effective way of teaching. Recent studies have shown that physical models play a very important role in design innovation and creativity. Building and testing such models can lead designers …


First Principles Study On Inp (001)-(2 × 4) Surface Oxidation, Santosh Kc, Weichao Wang, Hong Dong, Ka Xiong, Roberto Longo, Robert Wallace, Kyeongjae Cho Mar 2013

First Principles Study On Inp (001)-(2 × 4) Surface Oxidation, Santosh Kc, Weichao Wang, Hong Dong, Ka Xiong, Roberto Longo, Robert Wallace, Kyeongjae Cho

Faculty Publications

A theoretical study of the oxidation of InP(001)-(2 × 4) surface is performed using density functional theory methods. Our results on surface oxidation show that the oxygen adsorption does not produce any gap states in the bulk InP band gap, due to the saturation of surface In dangling bonds, whereas substitutional oxygen atoms produce gap states. This study also shows that the surface stability increases with the oxygen content, indicating a strong tendency for surface oxidation. Our results help to clarify the origin of surface gap states upon surface oxidation and provide an insight at the atomic level the mechanism …


Interfacial Bonding And Electronic Structure Of Hfo2/Gasb Interfaces: A First-Principles Study, Ka Xiong, Wei-Hua Wang, Dmitry Zhernokletov, Santosh Kc, Roberto Longo, R. Wallace, Kyeongjae Cho Jan 2013

Interfacial Bonding And Electronic Structure Of Hfo2/Gasb Interfaces: A First-Principles Study, Ka Xiong, Wei-Hua Wang, Dmitry Zhernokletov, Santosh Kc, Roberto Longo, R. Wallace, Kyeongjae Cho

Faculty Publications

The interfacial bonding and electronic structure of HfO2/GaSb interfaces has been investigated through first principles calculations. The calculated electronic structures of these interfaces reveal that some O-rich interfaces are semiconducting interfaces without any gap states. In contrast, for the interfaces with lower interfacial O content, gap states appear in the GaSb band gap, close to the conduction band. The valence band offsets are found to vary from 2.2 eV to 3.6 eV, depending on the interfacial O content. Our results suggest that GaSb is a suitable material to form high quality interface with HfO2.


Querie: Collaborative Database Exploration, Magdalini Eirinaki, S. Abraham, N. Polyzotis, N. Shaikh Jan 2013

Querie: Collaborative Database Exploration, Magdalini Eirinaki, S. Abraham, N. Polyzotis, N. Shaikh

Faculty Publications

Interactive database exploration is a key task in information mining. However, users who lack SQL expertise or familiarity with the database schema face great difficulties in performing this task. To aid these users, we developed the QueRIE system for personalized query recommendations. QueRIE continuously monitors the user’s querying behavior and finds matching patterns in the system’s query log, in an attempt to identify previous users with similar information needs. Subsequently, QueRIE uses these “similar” users and their queries to recommend queries that the current user may find interesting. In this work we describe an instantiation of the QueRIE framework, where …


Solid-Fuel Regression Rate Modeling For Hybrid Rockets, Francesca Favaro, W. Sirignano, M. Manzoni, L. Deluca Jan 2013

Solid-Fuel Regression Rate Modeling For Hybrid Rockets, Francesca Favaro, W. Sirignano, M. Manzoni, L. Deluca

Faculty Publications

The regression rate of the solid fuel is a primary parameter in the performance analysis for a hybrid rocket. Many studies in the past few years have theoretically claimed, or experimentally shown, a dependence of the regression rate on the chamber total pressure. Such behavior is generally traced back to the presence of oxygen below the flame zone and of heterogeneous reactions occurring at the surface and affecting the pyrolysis law. An experimental program was performed at the Space Propulsion Laboratory of the Politecnico di Milano showing, within the explored operating conditions and the associated uncertainty bands, a neutral trend …


Examining Design Fixation In Engineering Idea Generation: The Role Of Example Modality, Vimal Viswanathan, Julie Linsey Jan 2013

Examining Design Fixation In Engineering Idea Generation: The Role Of Example Modality, Vimal Viswanathan, Julie Linsey

Faculty Publications, Mechanical Engineering

Design fixation is a major concern in engineering idea generation because it restricts the solution space in which designers search for their ideas. For designers to be more creative, it is essential to mitigate their fixation. The majority of studies in the literature investigate the role of pictorial stimuli in design fixation; however, the role of examples presented in other formats, including physical prototypes, is largely unknown. This paper presents a study that compares design fixation, in novice designers, caused by pictorial and physical representations. The effects of defixating materials proposed by Linsey et al. (2010) are also investigated. The …


Efficient Space Dedication To Bus Rapid Transit Or Light Rail Systems, Jacob Tsao, A Pratama Jan 2013

Efficient Space Dedication To Bus Rapid Transit Or Light Rail Systems, Jacob Tsao, A Pratama

Faculty Publications

Dedicating two lanes and passenger platforms to transit typically requires taking the same space away from general use. This may affect public support. This paper proposes efficient geometric configurations for a two-dedicated-lane BRT or light rail system that requires a minimum amount of right-of-way along a busy commute arterial. In many current busy commute corridors, a significant part of the street median is underused or unused for traffic purposes. The efficiency is achieved ainly by using the street median between a left-turn lane and its counterpart located at the intersection on the other end of the same street section and …


Mechanical Properties Of Human Amniotic Fluid Stem Cells Using Nanoindentation, Ashkan Aryaei, Ambalangodage Jayasuriya Jan 2013

Mechanical Properties Of Human Amniotic Fluid Stem Cells Using Nanoindentation, Ashkan Aryaei, Ambalangodage Jayasuriya

Faculty Publications

The aim of this study was to obtain nanomechanical properties of living cells focusing on human amniotic fluid stem (hAFS) cell using nanoindentation techniques. We modified the conventional method of atomic force microscopy (AFM) in aqueous environment for cell imaging and indentation to avoid inherent difficulties. Moreover, we determined the elastic modulus of murine osteoblast (OB6) cells and hAFS cells at the nucleus and cytoskeleton using force–displacement curves and Hertz theory. Since OB6 cell line has been widely used, it was selected to validate and compare the obtained results with the previous research studies. As a result, we were able …


The Influence Of Personality And Ability On Undergraduate Teamwork And Team Performance, Jinny Rhee, David W. Parent, Anuradha Basu Jan 2013

The Influence Of Personality And Ability On Undergraduate Teamwork And Team Performance, Jinny Rhee, David W. Parent, Anuradha Basu

Faculty Publications

The ability to work effectively on a team is highly valued by employers, and collaboration among students can lead to intrinsic motivation, increased persistence, and greater transferability of skills. Moreover, innovation often arises from multidisciplinary teamwork. The influence of personality and ability on undergraduate teamwork and performance is not comprehensively understood. An investigation was undertaken to explore correlations between team outcomes, personality measures and ability in an undergraduate population. Team outcomes included various self-, peer- and instructor ratings of skills, performance, and experience. Personality measures and ability involved the Five-Factor Model personality traits and GPA. Personality, GPA, and teamwork survey …


An Intuitive Design Pattern For Sequentially Estimating Parameters Of A 2k Factorial Experiment With Active Confounding Avoidance And Least Treatment Combinations, H.-S. Jacob Tsao, Minnie Patel Jan 2013

An Intuitive Design Pattern For Sequentially Estimating Parameters Of A 2k Factorial Experiment With Active Confounding Avoidance And Least Treatment Combinations, H.-S. Jacob Tsao, Minnie Patel

Faculty Publications

2k Full factorial designs may be prohibitively expensive when the number of factors k is large. The most popular technique developed to reduce the number of treatment combinations is the fractional factorial design; confounding in estimating the model parameters naturally results in various resolution and aberration levels. While very useful, these resolution levels may not satisfy experimenters’ requirements for estimatibility and cost reduction. For example, while Resolution V ensures a common requirement that no two-factor interactions are confounded, it also imposes an often undesired restriction that a main effect cannot be confounded with a three-factor interaction, which may very well …