Angela Trego

Purpose: – The purpose of this paper is to show that cafeteria style grading actually provides a course structure which encourages students to go beyond expectations. Design/methodology/approach: – Three instructors offered a total of 13 sections of a general education science class called “Fundamentals of Technology” from January 2012 to December 2013 using a cafeteria-style grading method. This means students get to choose to do those assignments, quizzes or tests that appeal to their own learning interests or styles and do not need to complete all the assignments to get an A grade. Rather, they complete those assignments desired in order to earn the applicable points. This paper researches the combined results of over 400 students to assess the success of cafeteria style grading. Findings: – These instructors found that half the students overall obtain an A grade and 9 percent of all students actually go above and beyond the requirements of an A grade by at least 5 percent. Actually, about 4 percent of students complete more than is required by an additional 10 percent or more. Originality/value: – Cafeteria style grading is a little researched methodology for student assessment. The research shows that cafeteria style grading actually provides a course structure which encourages students to go beyond expectations.

Article Development of a System for Corrosion Diagnostics and Prognostics was published on April 1, 2007 in the journal Corrosion Reviews (volume 25, issue 1-2).

Newly developed advanced aircraft structures are utilizing composite technology for improving stiffness, strength and weight properties. Such structures are commonly found in inaccessible regions where current NDE techniques are limited. The development of low profile, distributed, embeddable, real-time, optical fiber sensors capable of detecting the onset of composite failure in aircraft structures would eliminate a significant portion of related maintenance costs. Notable composite failures that are difficult to assess include delaminations and moisture ingression issues. Optical fiber-based sensors add the inherent advantages of being lightweight, low profile, immune to EMI, resistant to harsh environments, and highly sensitive to a variety of physical and chemical measurements. Optical fiber-based sensors can also be embedded directly into the composite part during manufacturing and co-cured. This creates a monitoring system that has little impact on the properties of the final part while providing significant benefits. Fiber optics embedded in composite honeycomb panels were fabricated and tested using ground - air - ground thermal cycles to determine moisture ingression monitoring capabilities of the sensors. Two different types of moisture sensing fiber optics were measured. One type of installed moisture sensor is based off of a Bragg grating system, while the other moisture sensor is based off of a long period grating system. Presented herein is a comparison of the two different types of fiber optic sensors that monitored the moisture ingression in honeycomb panels.

Luna Innovations has developed a prototype 8-channel fiber optic sensor system to demonstrate fiber optic sensor operation in flight environments. As an intial flight demonstration, long period grating (LPG) relative humidity sensors along with extrinsic Fabry-Perot interferometric (EFPI) pressure and temperature sensors were installed in an aging Delta 767-300ER jet. The fiber optic signal-conditioning system is a multi-purpose platform that can also be used to operate other types of fiber optic LPG and EFPI sensors, including strain gages, metal-ion corrosion sensors, and fiber Bragg grating (FBG) sensors. The system configuration and operation is described.

Crashes between passenger vehicles and large tractor trailer vehicles often result in serious injuries and death. There have been few studies of this class of crash involving the side of the large tractor trailers and the passenger vehicles. Studies have shown that side underrides are underreported in crash records. A literature search has shown that there are no generally accepted methodologies to document and scientifically reconstruct a side underride accident. Some of the problems existed because there was a general lack of information on the side underride crash. Rear underride crashes were being studied which yielded helpful information. This led the authors to study a series of trailer side underride crashes that were performed to determine if there were sufficient relationships between passenger vehicle body and roof styles and the side of large highway trailers to allow the development of a general formula for underride impact speed analysis of a vehicle where the roof and roof support structure of the vehicle was damaged. These tests provided valuable insight into the relationships between passenger vehicle roof structures and the sides of large box trailers.

A primary concern with composite repair patches is the potential degradation of load transfer capabilities due to aging and environmental effects. The development of low profile, distributed, embeddable, real-time, optical fiber sensors capable of detecting the onset of patch delamination on repaired regions of the aircraft would eliminate a significant portion of the related maintenance costs as well as improve confidence levels in the technology. The presented sensing system is comprised of optical fiber long period gratings (LPGs) for chemical measurement and Bragg gratings for strain measurement. The sensors can be multiplexed together to monitor the structural health of the patch system and status of any remaining damage in the parent structure. The LPG sensors operate based on specially designed sensing coatings which cause a measurable change in the refractive index 'seen' by the LPG in the presence of target molecules. In this configuration, LPGs can be used to detect moisture infiltration and other chemical changes within a localized environment. Complementary to the long period grating, Bragg grating strain sensors can be fabricated on the same optical fiber to measure load transfer and composite delamination in patches used to repair cracks that occur in aging aircraft.

Fiber optic grating sensors written into polarization preserving optical fiber may be used to monitor multidimensional strain fields in composite materials. This paper provides an overview of the characterization and test of multiaxis fiber grating sensors formed by writing 1300 and 1550 nm fiber gratings into polarization preserving optical fiber. A discussion of the usage of these multiaxis fiber grating sensors to measure two and three dimensional strain fields will be made. A brief review of practical applications of the technology to measure shear strain, transverse strain gradients as well as axial and traverse strain will be made with emphasis on aerospace and civil structure applications.

Previously, the results of embedding multi-axis fiber gratings into adhesively bonded joints were discussed. This paper presents more information on the testing of the adhesive joints and techniques employed to successfully embed a fiber grating sensor into such structures. These techniques include orienting the fiber, marking its orientation, and preparing it for embedment into the adhesive. Also discussed are strain relief methods for the egress of the fiber.