Investigation of Protein/Lipid Interactions via Scanning Probe Acceleration Microscopy: Theory and Experiment

There is great interest in the application of proximal probe techniques to simultaneously image and measure mechancial properties of surfaces with nanoscale spatial resolution. There have been several innovations in generating time-resolved force interaction between the tip and surface while acquiring a tapping mode AFM image. These tip/sample forces contain information regarding mechanical properties of surfaces in an analogous fashion to a force curve experiment. Here, we demonstrate, via simulation, that the maximum and minimum tapping forces change with respect to the Young’s modulus and adhesiveness of a surface, but the roughness of the surfaces has no effect on the tapping forces. Using these changes in tapping forces, we determine the mechanical changes of a lipid membrane after exposure to a huntingtin exon1 (htt exon1) protein with an expanded polyglutamine (polyQ) domain. Expanded polyQ domains in htt is associated with Huntington’s disease, a genetic neurodegenerative disorder. The htt exon1 protein caused regions of increased surface roughness to appear in the lipid membrane, and these areas were associated with decreased elasticity and adhesion to the AFM probe.

Reasoning: Source of Variability in the Boothroyd and Dewhurst Assembly Time Estimation Method

This paper evaluates the effect of making a subjective decision in a design for assembly time analysis. An example is found in the first set of questions for estimating handling time of a part the user chose “parts are easy to grasp and manipulate” as opposed to “parts present handling difficulties”. The subjectivity is explored through a study of assembly time estimates generated by a class of mechanical engineering students in the time analysis of a clicker pen based on the Boothroyd and Dewhurst estimation method. The assembly times calculated by the class ranged from a minimum of 23.64 seconds to a maximum of 44.89 seconds (range of 21.25 seconds). This large range in results serves as motivation in determining the effect that answering a subjective decision has on the resulting assembly time estimate. Initial results indicate that not answering the first level of subjective questions will result in assembly time estimate within 15% of the time had the subjective question been answered. The probability density plots of the time estimates also indicates that 63% of the time, the estimated assembly time without making the subjective decision will fall within the normal distribution had the subjective decision been made. This provides evidence that there is an opportunity to reduce the amount of subjective questions that a user must answer to estimate the assembly time of a product.

Module Definition for Product-Service Systems

More and more manufacturing firms are transitioning to more serviced based offerings. It has been shown that a useful integrated bundle of services through a complimentary product can be a better business model than just adding support services to a product as tactical responses to customer needs. In order for companies to be able to define these integrated bundles in an efficient and systematic manner, a process is needed. In the paper we propose a new method to define modular services, ones that can be leveraged efficiently as driving entities, and which can be provided using several product offers. The service modules consist of services modularized for leveraging across several products. The method builds upon the foundations in product platform and modularity research extending it to product service systems. Further, we introduce alternative service modular platform leveraging strategies.

Characterization of Piezoelectric Nanofiber Composites Acoustic Emission Sensor for Structure Health Monitoring

A nanoscale active fiber composites (NAFCs) based acoustic emission (AE) sensor with high sensitivity is developed. The lead zirconate titanate (PZT) nanofibers, with the diameter of approximately 80 nm, were electrospun on a silicon substrate. Nanofibers were parallel aligned on the substrate under a controlled electric field. The interdigitated electrodes were deposited on the PZT nanofibers and packaged by spinning a thin soft polymer layer on the top of the sensor. The hysteresis loop shows a typical ferroelectric property of as-spun PZT nanofibers. The mathematical model of the voltage generation when the elastic waves were reaching the sensor was studied. The sensor was tested by mounting on a steel surface and the measured output voltage under the periodic impact of a grounded steel bar was over 35 mV. The small size of the developed PZT NAFCs AE sensor shows a promising application in monitoring the structures by integration into composites.

Combining Life Cycle Assessment and Linear Regression Analysis to Determine Significant Design Characteristics

For designers it is difficult to pin-point the design characteristics that could be changed to reduce the environmental impact of their products. This paper describes a method for determining the design characteristics that have a significant relationship with environmental impact that arises at product end-of-life. In this method, Life Cycle Assessment (LCA) and Linear Regression Analysis (LRA) are combined. LCA is used to quantify the environmental impact of products from the extraction of their raw materials to their disposal. LRA is used to determine the design characteristics that have the most significant relationship with environmental impact. Combining LCA and LRA gives the designer the ability to (1) establish a relationship between design characteristics and their environmental impact, (2) determine the most significant design characteristics that influence environmental impact, and (3) validate design changes with their influence on product environmental impact. In the case study described here, the design characteristic, Volume, is shown to have significant relationship with the end-of-life environmental impact of cellular phones. This trend is consistent with the results of the one-phase end-of-life disposition assessments that evaluated disassembled cellular phones. With the results of this method, designers can focus their sustainable design efforts on modifying and improving the design characteristics that have the strongest relationship with environmental impact.

A Multi-Aspect Modeling Method for Service Flow Simulation Using Scene Transition Nets (STNs)

Recently, a new academic field, “service engineering” has been very actively investigated. However, there are few effective methods and tools to simulate and evaluate services designed based on the concept of service engineering. In the past, the authors proposed a service flow simulation method using scene transition nets (STN) which is a graphic modeling and simulation method for discrete-continuous hybrid systems. However, this method does not consider how to model and simulate complex service flows including multiple layered, parallel, and interrupted structures and it is difficult to construct STN models of such complex systems using the existing STN concepts. In this paper, the authors propose a new STN modeling method using “multi-aspect STN modeling “ concepts in order to provide easy methods for modeling of such complex services. The experimental results for the modeling and simulation of a nursing service demonstrate the effectiveness of the proposed method.

Tunability and Sub- and Superharmonic Entrainment of Limit Cycles in CW Laser Driven MEMS

The nonlinear dynamics of nanoscale mechanical oscillators driven both inertially and by CW laser light are explored experimentally. The oscillators are singly and doubly-supported beams, 200 nm thick with lengths up to 40 microns. The optically thin beams, suspended over a Si substrate, form a Fabry-Pérot interferometer. The net effect is that the fractions of absorbed and reflected light are periodic functions of the gap. Thus, monitoring the reflected signal allows the motion to be measured. In addition, motion of the device through the interference field modulates the temperature and hence thermal stress of the oscillator. The thermal stress provides a thermo-mechanical drive to the beam, resulting in nonlinear feedback that can drive the beam into limit cycle oscillation. The laser power needed for the onset of limit cycles is studied as a function of beam geometry, and laser placement. The oscillators show both hardening and softening behaviors, sub- and superharmonic entrainment and wide frequency tunability.

Design of a Large Scale Vertical Stabilizer Wind Tunnel Model for Active Flow Control Research

The design, fabrication and installation of an approximately 1/6 scale model of an aircraft vertical stabilizer for research in Active Flow Control (AFC) is discussed. Highlighted are the unique design requirements of wind tunnel models, the specialized fabrication techniques employed to create them and the required close collaboration between industry, government and three academic institutions. The design of the model involves often competing constraints imposed by structural, instrumentation, aerodynamic, manufacturability and research-agenda considerations as well as cost and schedule. Instrumentation requires hundreds of pressure ports and six-axis force/torque sensing. Aerodynamic considerations necessitate high manufacturing precision, highly-skilled fabrication techniques and careful observance of model geometry throughout the design and fabrication processes. A scale model of a vertical stabilizer for AFC research was successfully designed, fabricated and deployed. The collaboratively designed model satisfies the structural, aerodynamic and research design constraints, and furthers the state of the art in Active Flow Control research.

Sustainable Product Family Planning Based on Product Life Cycle Simulation

Product variety and improvements are the most important issues of today’s product development. Product family engineering is considered to be an effective approach to create new products that apply variability with decreased costs and time. However, given the environmental considerations, this study proposed sustainable product family planning which is a systematic design framework of product function; structure and lifecycle options (i.e. reduce, reuse and recycle). First, relationships between the diverse customer needs, product’s technical attributes and physical architecture are analyzed. Based on the analysis, certain product family plan including a product model change plan, a general product structure model, technical specifications and lifecycle options of each product in the family are established. A life cycle simulation tool is then developed for 1) easy building of various production strategies, product use scenarios and market competition cases, etc.; and 2) environmental and economic evaluations of the product family plan. A case study of personal computers (PCs) product family planning demonstrates an implementation of the proposed methods.

Wind Turbine Blade Design and Analysis With Tubercle Technology

The objective of this project is to construct a CAD model for tubercle wind turbine. Once the model is developed a complete CFD analysis of the flow pattern around the wind turbine will be carried out. The main objective of the study is to analyze and compare the performance of the tubercle wind turbine with the usual wind turbine. The power developed by both the turbine blades can be compared to support the use of tubercle. The tubercles are very effective for increasing the lift without stalling. The main objective of this project is to study the aerodynamic advantages of tubercle turbine blade. The effort will be to compare the obtained results with the straight blade of the same airfoil. This will provide insight into the advantages of using the tubercle blade. This technology being new the study is done numerically to study the overall effect of the tubercle.