Hockey sticks

Although wood is the traditional material for hockey sticks, composites do provide a more durable stick with the ability to efficiently transfer energy and reduce player fatigue. The sticks can be produced as a single piece construction with combined shaft and blade, or a two-piece unit utilizing a separate shaft (cf a golf shaft). Carbon fiber is used in the more expensive sticks. Bending Branches produce a wood/carbon fiber stick. 

Exel Oy manufacture carbon/glass replacement blades and are using triaxial braiding to produce a stick which can be tailored with a number of flex points, each with its own stiffness rating. 

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Mixed-solvent solutions of various cosolvent-water proportions are titrated and psKa (the apparent pKa) is measured in each mixture. The aqueous pKa is deduced by extrapolation of the psKa values to zero cosolvent. This technique was first used by Mizutani in 1925 [181-183]. Many examples may be cited of pKa estimated by extrapolation in mixtures of methanol [119,161,162,191,192,196,200], ethanol [184,188-190,193], propanol [209], DMSO [212,215], dimethylformamide [222], acetone [221], and dioxane [216]. Plots of psKa versus weight percent organic solvent, Rw = 0 — 60 wt%, at times show either a hockey-stick or a bow shape [119]. For Rw > 60 wt%, S-shaped curves are sometimes observed. (Generally, psKa values from titrations with Rw > 60 wt% are not suitable for extrapolation to zero cosolvent because KC1 and other ion pairing interferes significantly in the reduced dielectric medium [223].)... 

Apart from the parent compound 1 and its very simple alkyl derivatives, 1,3,4-oxadiazoles are solids. Solid oxadiazoles containing biphenyl or triphenyl substituents exhibit interesting properties upon heating. The symmetric 2,5-bisbiphenyl-4-yl-l,3,4-oxadiazole 38 melts into an isotropic phase showing small monotropic mesophase. By contrast, the asymmetric (hockey stick-shaped) mesogen 2-terphenyl-4-yl-5-phenyl-l,3,4-oxadiazole 39 exhibits a more stable enantiotropic liquid crystalline phase (a smectic phase as well as a nematic phase) <2001PCB8845>. 

During the past millennium the average global temperature was essentially flat until about 1900, then spiked upward, like the upturned blade of a hockey stick. Some view this as a clear indication that humans are warming the globe, but others hold that the climate is undergoing a natural fluctuation not unlike those in past eras. 

Appell, David, "Behind the Hockey Stick." Scientific American, Volume 292, pp 34-35, March 2005. 

Hockey sticks that normally sell for 89.00 are on sale for 3 5 % off the regular price. There is also a 6% sales tax. How much will the stick cost after the sale and the sales tax ... 

When high-school cross-country runners were exposed for 1 h to photochemical oxidants at 0.03-0.3 ppm, their performance decreased with increasing concentration. A statistical test for threshold values (regression using/ hockey stick functions) applied to these data gives a threshold estimate of 0.12 ppm, with a 95% confidence interval of 0.067-0.163 ppm. ... 

There are obvious inadequacies in the established values. First, it was assumed that the oxidant standard is a surrogate standard for photochemical oxidants, with ozone as the indicator. However, it is clear that very low concentrations of specific irritants, such as peroxyacetyl-nitrate (PAN), are sufficient to cause eye irritation. Second, some of the statistical techniques used to determine the lowest concentration at which effects are observed were inconsistent and undocumented. A hockey stick fimction was sometimes used to find an effect threshold. 

Hasselblad, V., G. Lowrimore, W. C. Nelson, J. Creason, and C. J. Nelson. Regression Using Hockey Stick Functions. Durham. N.C. U.S. Department of Health. Education, and Welfare. Public Health Service. Environmental Health Service, National Air Pollution Control Administration (in-house report, 1970). 5 pp. 

A comparison with capital market expectations is a valuable touchstone for in-house corporate planning. Currently, capital market expectations will fairly frequently be much lower than internal plans, indicating a possibly over-optimistic estimation (the well-known hockey stick ).61... 

The relationship between a covariate and individual model parameters should be exploratively investigated by a graphical presentation which often suggests a mathematical function that might best describe the relationship. The most commonly used functions are linear functions, so called hockey stick functions as well as exponential functions. The linear relationship can be implemented according the following equation ... 

If the covariate covers a large range of values the data may not be satisfactorily described by the above presented linear model. An alternative model for those situations is the hockey stick model described in the following equation. 

The hockey stick function assumes a linear relationship until a node point is reached afterwards another relationship can be used. In the above equation, the median was chosen as the node point and for all individuals having a larger covariate value than the median value no influence of the covariate was assumed. 

Payback. This is a measure of how quickly the investment will be paid back. This is a time measurement. Some companies have hurdle times that dictate that a project must be paid back in a certain number of months before it will be approved. This is often done to overcome the hockey stick curves where returns are so far out that meeting them is very questionable. 

V. Hasselblad, J.P. Creason, and W.P.Nelson (1976), Regression using Hockey stick functions, EPA report 600/1-76-024, Research Triangle Park, NjC. 

In foam injection-molded parts the anooth-skinned resilient foam produces a tough energy-absorbing structure that is being used as a wood substitute in athletic products such as lacrosse-stick heads and hockey-stick blades. Protective structures for helmets and automotive parts are under development. All are being produced in densities ranging for 0.35 to 0.7 g/cc (22 to 44 Ib/ft ). In those applications where added sti ess is desirable the use of glass or titanate fiber reinforcement with the foamed structure is very effective (6). 

Spread titered bacteria on the membrane using a Pasteur pipette bent above a flame into the form of a hockey stick. About 0.1 ml with lO bacteria are suitable for a 82 mm diameter plate (depending on experience avoid spreading on the 3-5 mm edge of the membrane). 

FIGURE 5-2 Plots of the logit and hockey-stick dose-response analysis of the relationship between retarded walking and maternal-hair concentrations during gestation. The two dose-response curves are shown by solid lines. The shaded area represents the 95% confidence limits from kernel smoothing. Source Cox et al. 1989. Reprinted with permission from Environmental Research-, eopyright 1989, Academic Press. 

To date, many conformational effects have been proposed, all of which have had some kind of experimental verification. Many of them have special names, e.g. "gauche rabbit-ears hockey-sticks ... 

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