Legal wrangling precipitated by the Americans With Disabilities Act (ADA) has resulted in courts adopting a narrow view of disability. This narrow categorical disability definition is in conflict with current mental health and educational practice that presumes an inclusive view of disability. Test accommodations for licensing exams based on learning impairments provide an example of the conflict generated by legal versus mental health views of disability. Mental health practitioners often support test accommodation requests for students who do not meet the ADA's strict threshold for disability determination. Mental health practitioners must understand the ADA definition of disability, and test organizations need to examine goals and alter standard practice in a manner that is fair and equitable independent of learning impairments. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
A composite grid-stiffened structure concept was selected for the payload fairing of the Minotaur launch vehicle. Compared to sandwich structures, this concept has an advantage of smaller manufacturing costs and lighter weight. To reduce weight the skin pockets are allowed to buckle visibly up to about 0.5 cm peak displacement.
Various failure modes were examined for the composite grid-stiffened structure. The controlling criterion for this design was a joint failure in tension between the ribs and skin of the structure. The identification of this failure mechanism and the assessment of bounding strains required to control it required extensive test and analysis effort. Increasing skin thickness to control skin buckling resulted in reduced strains between the skin and ribs.
Following the identification of the relevant failure criteria, a final design for the fairing was generated. The resulting 6 m tall fairing was constructed of a tow-placed carbon fiber composite grid structure that was over-wrapped to create a laminated skin. Upon completion of curing and machining, the fairing was cut in half to create the classic “clam-shell” fairing. Static qualification testing demonstrated the structural integrity of the fairing, thereby proving the design and manufacturing process. Loads were applied incrementally in a static loading scenario. The applied load envelope exceeded worst-case dynamic flight conditions with an added safety factor of 25%. At peak load the fairing maintained structural integrity while remaining within the required displacement envelope for payload safety.
Data were collected during the test from a variety of sensors including traditional displacement transducers and strain gages. In addition, full field displacement was monitored at critically loaded fairing sections by means of digital photogrammetry. This paper summarizes the test results, presents the overall performance of the fairing under the test loads, correlates test response and analysis, and identifies lessons learned.
Work continues at the Air Force Research Laboratory (AFRL) and Boeing to identify means of further controlling tensile failure of the un-reinforced polymer bonded joint between the ribs and skin. Stiffening of skin adjacent to the joints and introduction of lightweight foam jackets at the interior of the fairing both show promise of delaying joint failure to higher loads. 相似文献
[Correction Notice: An erratum for this article was reported in Vol 1(4) of Training and Education in Professional Psychology (see record 2007-18975-009). The biography for the third author was incorrect. It should read as follows: GREGORY KEILIN is an Assistant Director at the Counseling and Mental Health Center at the University of Texas at Austin and a former Chair of APPIC. He received his doctorate in Counseling Psychology from Colorado State University. His current research interests include supply and demand issues in professional psychology.] Academic training programs in clinical psychology vary in the emphasis that they place on science and practice, and this paper examines whether these differential emphases are linked to distinctive internship outcomes. In a study of 2,130 internship applicants from clinical psychology programs, differences were noted among practice-oriented programs, balanced science-practice programs, and science-oriented programs. Against a backdrop of some similarities, a differential emphasis on science and practice within academic training programs was related to significantly different internship match rates, as well as to successful matching in qualitatively different internship settings. Results provided qualified support for future work that might further address the relationship between academic training programs and outcomes in the field of clinical psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
To date the design of structures using topology optimization methods has mainly focused on single-objective problems. Since real-world design problems typically involve several different objectives, most of which counteract each other, it is desirable to present the designer with a set of Pareto optimal solutions that capture the trade-off between these objectives, known as a smart Pareto set. Thus far only the weighted sums and global criterion methods have been incorporated into topology optimization problems. Such methods are unable to produce evenly distributed smart Pareto sets. However, recently the smart normal constraint method has been shown to be capable of directly generating smart Pareto sets. Therefore, in the present work, an updated smart Normal Constraint Method is combined with a Bi-directional Evolutionary Structural Optimization (SNC-BESO) algorithm to produce smart Pareto sets for multiobjective topology optimization problems. Two examples are presented, showing that the Pareto solutions found by the SNC-BESO method make up a smart Pareto set. The first example, taken from the literature, shows the benefits of the SNC-BESO method. The second example is an industrial design problem for a micro fluidic mixer. Thus, the problem is multi-physics as well as multiobjective, highlighting the applicability of such methods to real-world problems. The results indicate that the method is capable of producing smart Pareto sets to industrial problems in an effective and efficient manner. 相似文献
In this work we demonstrate the effects of a post processing high temperature anneal on the reliability of ultra-thin SiON layers fabricated into both nmos and pmos devices in terms of the initial gate leakage current, stress induced leakage current (SILC), and the time dependent dielectric breakdown behaviour. The devices under consideration were annealed at several temperatures up to 500 °C. We show that different mechanisms dominate the leakage behaviour at different temperatures by examining the relative leakage in the low voltage range. In particular for pmos devices, the emptying of electron traps induced by temperature and subsequent annealing of these traps alters the leakage current profiles significantly, dependent on anneal temperature. We show that annealing improves the time dependent dielectric breakdown (TDDB) lifetimes of nmos devices and examine the reasons for this. 相似文献
In this work we examine the positive bias temperature instability (PBTI) and stress induced leakage current (SILC) reliability of nFET devices with thin (2.5 nm) ZrO2 gate dielectric layers. nFET devices show anomalous PBTI behavior in the form of a negative threshold voltage (Vt) shift during positive bias stress with little temperature dependence and it is not ‘frozen out’ at lower temperatures, indicating a single non-diffusion based mechanism. Correlations between the PBTI and the stress induced leakage current (SILC) suggest that the PBTI effect originates from trapping into empty defects which are initially detected as SILC and located just below the silicon conduction band. These defects also appear to be linked to the time dependent dielectric breakdown behavior. 相似文献