Model verification of large structural systems

A methodology was formulated, and a general computer code implemented for processing sinusoidal vibration test data to simultaneously make adjustments to a prior mathematical model of a large structural system, and resolve measured response data to obtain a set of orthogonal modes representative of the test model. The derivation of estimator equations is shown along with example problems. A method for improving the prior analytic model is included

Methods for evaluating the predictive accuracy of structural dynamic models

Uncertainty of frequency response using the fuzzy set method and on-orbit response prediction using laboratory test data to refine an analytical model are emphasized with respect to large space structures. Two aspects of the fuzzy set approach were investigated relative to its application to large structural dynamics problems: (1) minimizing the number of parameters involved in computing possible intervals; and (2) the treatment of extrema which may occur in the parameter space enclosed by all possible combinations of the important parameters of the model. Extensive printer graphics were added to the SSID code to help facilitate model verification, and an application of this code to the LaRC Ten Bay Truss is included in the appendix to illustrate this graphics capability

A computer program for model verification of dynamic systems

Dynamic model verification is the process whereby an analytical model of a dynamic system is compared with experimental data, and then qualified for future use in predicting system response in a different dynamic environment. There are various ways to conduct model verification. The approach adopted in MOVER II employs Bayesian statistical parameter estimation. Unlike curve fitting whose objective is to minimize the difference between some analytical function and a given quantity of test data (or curve), Bayesian estimation attempts also to minimize the difference between the parameter values of that function (the model) and their initial estimates, in a least squares sense. The objectives of dynamic model verification, therefore, are to produce a model which: (1) is in agreement with test data, (2) will assist in the interpretation of test data, (3) can be used to help verify a design, (4) will reliably predict performance, and (5) in the case of space structures, facilitate dynamic control

Identification and analysis of factors affecting thermal shock resistance of ceramic materials in solar receivers

An analysis was conducted of the possible modes of thermal stress failure of brittle ceramics for potential use in point-focussing solar receivers. The pertinent materials properties which control thermal stress resistance were identified for conditions of steady-state and transient heat flow, convective and radiative heat transfer, thermal buckling and thermal fatigue as well as catastrophic crack propagation. Selection rules for materials with optimum thermal stress resistance for a particular thermal environment were identified. Recommendations for materials for particular components were made. The general requirements for a thermal shock testing program quantitatively meaningful for point-focussing solar receivers were outlined. Recommendations for follow-on theoretical analyses were made

An analytical basis for time-modulated random vibration testing

Approximated maximal vibratory response of linear excited system to time modulated stationary random vibratio

Sinergitas Kebijakan Program “Makassar Ta’ Tidak Rantasa” di Kota Makassar

Synergy of policies is important for the government to run its programs in order to achieve bigger gain. The aim of the research was to find out and analyze synergy of program policy “Makassar ta’ Tidak Rantasa’” (Our Clean Makassar) in Makassar City. The research used qualitative method. The data were obtained through observation, interview, and documentation to the informantion direction, data presentation, and conclusion drawing. The results of the research indicate that the Program Policy “Makassar ta’ Tidak Rantasa’” (Our Clean Makassar) is a 100-working-day pogram of mayor and vice mayor of Makassar abaut cleanliness. The programs coverning in this policy have not been maximally synergic one another. Consequently, Makassar is still “Rantasa’” (dirty) since there are some things that need improvement such as the formulation of problem solving, government’s role, and socialization to community. Sinergitas kebijakan penting bagi pemerintah dalam menjalankan program-programnya agar saling mengisi dan melengkapi perbedaan untuk mencapai hasil yang lebih besar dari pada jumlah bagian perbagian. Penelitian ini bertujuan mengetahui dan menganalisa Sinergitas Kebijakan Program “Makassar ta’ Tidak Rantasa’” di Kota Makassar. Metode penelitian yang digunakan adalah metode kualitatif. Pengumpulan data ditempuh melalui pengamatan, wawancara dan dokumentasi terhadap informasi yang terlibat langsung dalam pelaksanaan kegiatan tersebut. Sedangkan analisis data melalui proses reduksi data, penyajian data dan penarikan kesimpulan. Hasil penelitian menujukkan bahwa Kebijakan Program “Makassar ta’ Tidak Rantasa’” adalah program 100 hari kerja walikota dan wakil walikota Makassar, mengenai kebersihan. Program-program yang ada dalam kebijakan tersebut belum bersinergi secara maksimal, akibatnya Makassar tetap saja “Rantasa” (kotor), karena ada beberapa hal yang perlu dilakukan perbaikan misalnya perumusan penyelesaian masalah, peran pemerintah dan sosialisasi kepada masayarakat

First Record of Age 0+ Atlantic Whitefish, Coregonus huntsmani, from the Wild

A small school of juvenile Atlantic Whitefish (~20-30 individuals) were observed in the littoral zone of Hebb Lake (Petite Rivière watershed), Nova Scotia in June 2000. Of these, a single individual was captured with a beach seine, and confirmed to be a young-of-the-year specimen. This is the first documented report of the occurrence of wild Atlantic Whitefish juveniles. Occupation of the littoral zone into early summer by young-of-the-year Atlantic Whitefish may have implications for predation by invasive Smallmouth Bass