Quantitative prediction of growth patterns of surface fatigue cracks in tension plates

Different methods of prediction of the aspect ratio variability of growing surface fatigue cracks in tension plates are compared with experimental data. The objective is to identify the most accurate method. The comparison is based on a quantitative criterion as well as on statistical examination of the level of agreement with the data. Fifty-eight cracks are analysed. The total number of data points is 450 taken from 20 references. The solutions evaluated include theoretical as well as empirical formulas. The comparison shows that it is possible to predict the aspect ratio variability with standard deviation <0.070.     

A Study of the Complexation Between Danazol and Hydrophilic Cyclodextrin Derivatives

Complexation between danazol, a steroid used for endometriosis, and both hydroxypropyl- β-cyclodextrin (HPCD) and sulfobutyl ether-β-cyclodextrin (SBE) was studied in solution and solid state. Complexation was evaluated in solution using solubility studies and proton magnetic resonance (¹H NMR) spectroscopy, and in the solid state using x-ray diffraction, Fourier-transform infrared spectroscopy (FTIR)), and dissolution studies. Solubility studies suggested the existence of a 1:1 complex between danazol and either HPCD or SBE. ¹H NMR showed that complexation occurs by inclusion of the isoxazole ring of danazol into the cyclodextrin cavity in both cases. Powder x-ray diffraction indicated that danazol existed in a crystalline noncomplexed form at low danazol-to-cyclodextrin ratios in the coprecipitates prepared by solvent evaporation method, while at higher ratios danazol existed in an amorphous complexed form. This ratio was 1:10 w/w for HPCD and 1:20 for SBE; the higher ratio in the case of SBE is attributed to early precipitation of danazol from the solvent used for preparation. FTIR studies showed that the complexation was accompanied by a shift of the O-H stretching of danatol hydroxyl group to a higher frequency, which is attributed to the disruption of the intermolecular hydrogen bonding. The dissolution rate of danazol from HPCD coprecipitates was higher than crystalline danazol in aqueous-isopropanolic medium, while SBE coprecipitates showed reduced dissolution rates due to the low solubility of SBE in isopropanol. However, SBE coprecipitates showed higher dissolution rates in water than in the isopropanolic medium.     

Factors affecting growth and urease production by Trichophyton spp

BACKGROUND: Two to four percent of epileptics have their seizures triggered by flickering light, an effect which may be wavelength-dependent. We evaluated a patient with a long-standing history of light-induced petit mal seizures to determine if the seizures were triggered more effectively by a particular range of wavelengths and to determine whether this information could be used in the optometric management of such patients. METHODS: Flickering lights of different wavelengths but equal luminance were presented while the patient's electroencephalogram (EEG) and subjective reports were monitored. RESULTS: The EEG results were not significantly different for different wavelengths, but the patient reported that longer wavelength light induced stronger seizures more consistently. Based on these results we concluded that the patient might benefit from spectacles tinted to exclude transmission of red light. The patient was given 4 pairs of 85% transmission spectacles, which differed only in lens tint (red, yellow, green, and blue), to try over a period of time. The patient felt that the tinted lenses were not dark enough to decrease his seizures effectively and he has opted to wear standard sunglasses. CONCLUSIONS: We feel this case shows that patients with light-induced seizures can benefit from optometric consultation. Because the patient's subjective report identified the clearest wavelength effect, we feel that it is reasonable for the general practitioner to suggest deeply tinted lenses to reduce the frequency of seizures in these patients.     

A computational procedure to stabilize nonlinear sampled-data systems

In this paper, a sufficient condition for the stability of a class of nonlinear sampled-data systems, expressed in a matrix quadratic form, is derived. A programmed computational algorithm is constructed to implement the stabilization scheme. Application to third-order control problem is presented in order to demonstrate the developed procedure.     

Fuzzy convex cones and functions for ordinary and parametric programs

The fuzzy sets is a notion which generalizes all types of the existing sets. Many authors were interested in this new type, so they defined many related notions and investigated more of their properties.In this paper we study a new concept of fuzziness called fuzzy convexity by introducing the notion of fuzzy convex sets for mathematical programs and also for parametric programs. The connections between these notions and the ordinary ones are given and some of their characterizations are investigated.     

Solar desiccant systems for grain drying

The mathematical model for the Kathabar Spray-Cel System developed by the authors in a previous work was used to predict the temperature and humidity ratio of the air at the drying bin inlet. The unsteady grain cooling model developed by Huzayyin (Ph.D. dissertation, Kansas State Univ. at Manhattan (1972); Ref. [1]) is modified and coupled with the liquid desiccant system model to study the feasibility of using the system desiccated air in drying applications. The model shows the infeasibility of using desiccated air for grain drying. The liquid desiccant system was modified to simulate adiabatic operation and coupled to the drying model. The new system gave much better results, but its use for grain drying is still predicted to be economically unfeasible.     

OPTIMIZATION OF CONVECTIVE LONGITUDINAL FINS OF TRAPEZOIDAL PROFILE

This paper deals with optimum design of convective longitudinal fins of a trapezoidal profile. The optimum dimensions, and the associated heat dissipation, and efficiency are obtained in terms of dimensionless parameters, h√A_p/k and h_e/h. They are presented in graphical forms in order to aid thermal designers