Spokes

FIGURE 1 6 Molecular models of methane (CH4) (a) Framework (tube) models show the bonds connecting the atoms but not the atoms themselves (b) Ball and stick (ball and spoke) models show the atoms as balls and the bonds as rods (c) Space filling models portray overall molecular size the radius of each sphere approximates the van der Waals radius of the atom (d) An electrostatic potential map of methane... 

SpartanBuild software that you can use to build molecular models of various types include tube ball and spoke and space filling This text includes a number of mod eling exercises for you to do but don t limit yourself to them You can learn a lot by sim ply experimenting with SpartanBuild to see what you can make... 

FIGURE 3 1 The stag gered and eclipsed confer mations of ethane shown as ball and spoke models left) and as space filling models right)... 

FIGURE 3 6 The gauche and anti conformations of butane shown as ball and spoke mod els left) and as Newman projections right) The gauche conformation is less stable than the anti because of the van der Waals strain between the methyl groups... 

FIGURE 3 8 Ball and spoke and space filling models of methyl-methyl eclipsed conformation of butane... 

FIGURE 3 9 Ball and spoke models of pentane and hexane in their all anti (zigzag) conformations... 

FIGURE 3 14 (a) A ball and spoke model and (b) a space filling model of the boat confor mation of cyclohexane Torsional strain from eclipsed bonds and van der Waals strain involving the flagpole hydrogens (red) make the boat less stable than the chair... 

FIGURE 5 5 Ball and spoke and space filling models of as and trans 2 butene The space filling model shows the serious van der Waals strain between two of the hydrogens in as 2 butene The molecule ad justs by expanding those bond angles that increase the separation between the crowded atoms The combi nation of angle strain and van der Waals strain makes as 2 butene less stable than trans 2 butene... 

FIGURE 7 6 Ball and spoke models [left) wedge and dash drawings [center) and Fischer projections [right) of the R and S enan tiomers of bromochloro fluoromethane... 

One after the other select Wire Tube Ball and Spoke and Space Filling from the Model menu... 

Select Ball and Spoke from the Model menu... 

Vibrations appear most clearly when a molecule is displayed as a ball and spoke model... 

Ball and stick model (Section 1 10) Type of molecular model in which balls representing atoms are connected by sticks representing bonds Similar to ball and spoke models of Learning By Modeling... 

A constant force is applied to an ideal elastomer, assumed to be a perfect network. At an initial temperature Tj the length of the sample is Ij. The temperature is raised to Tf and the final length is If. Which is larger Ij or If (remember F is a constant and Tf > Tj) Suppose a wheel were constructed with spokes of this same elastomer. From the viewpoint of an observer, the spokes are heated near the 3 o clock position-say, by exposure to sunlight-while other spokes are shaded. Assuming the torque produced can overcome any friction at the axle, would the observer see the wheel turn clockwise or counterclockwise How would this experiment contrast, in magnitude and direction, with an experiment using metal spokes ... 

Cup anemometers have shaped cups mounted on the spokes of a wheel. The cups, under the action of the fluid forces, spin in a horizontal plane about a vertical shaft mounted in bearings. Vane or propeller types use a multibladed rotor, the axis of which is parallel to the flow direction as the rotating member. Both designs are commonly used for wind speed measurement or similar appHcations such as the velocity in ventilation ducts. Because of inertia, anemometers are most accurate under steady conditions. Velocity fluctuations cause readings that are too high. 

Recently, composite wheels have become popular. While composite wheels may eliminate the use of spokes, they are costly and do not necessarily reduce the weight of the wheel or the energy necessary to initiate revolution. As a result, composite wheels do not always provide an adequate alternative to wheel covers as they may not be readily applicable to all uses in which spoke wheels may be found. Traditional spoke wheels are still the predominant wheel system for most two-wheeled vehicles. 

Laurion, U.S. Pat. No. 3,847,443, discloses an oma-mental wheel element which is designed to fit between the spokes, inside a wheel. Strazis, U.S. Pat. No. 4,682,821, discloses a semi-rigid, tension attached bicycle wheel cover assembly intended to improve the aero-dynamic efficiency of bicycle wheels. Monte, U.S. Pat. 

No. 4,732,478, discloses a streamlined wheel for bicycles which comprises two hollow half shells which are joined to create a rim for support of a tire. Imao et al, U.S. Pat. No. 4,729,605, and Viellard, U.S. Pat. No. 4,741,578, discloses spokes and wheel components useful in composite wheels. 

However, these systems fail to disclose an inexpensive means of easily improving the aerodynamic properties of a spoke wheel with minimal manual effort. As 65 can be seen, while any number of alternative wheel covers are available, these systems have certain shortcomings which have not yet been satisfied by the art. 

The present invention provides a wheel cover which improves the aerodynamic properties of the hub-rim-spoke wheels. The wheel cover of the present invention is preferably made of a light weight synthetic or natural polymer, fabric or paper film which is adhesively applied to a wheel through simple manual application. In turn, the aerodynamic wheel cover of the present invention may also be easily removed and replaced to allow on-road repairs of spoke, hub, or rim. 

Preferably, the wheel cover of the present invention may be easily applied without extended mechanical or manual effort merely by adhesively applying the cover to the wheel spokes or rim. Once in place, the wheel cover may be shrunk to size so as to provide a tightly fit cover. 

FIG. 2 is a side plan view of one embodiment of the wheel cover of the present invention shown in FIG. 1 with the wheel cover applied to a spoke wheel rim. 

A triangular shaped wheel cover with the center cut out to provide hub access was then applied to a wheel. The cover was constructed from a heat shrinkable poly- 10 olefin ftlm. Tape was attached to the apex points of the triangle. The tape liner was removed and the three adhesive sites were fastened to the spokes. As an identical complementary cover was then applied to the opposite face of the wheel in a mirror image fashion. The 1 adhesive contact points were positioned to encapsulate the spoke on either side within the adhesive contact point. Heat was then used to shrink the covers and achieve a wrinkle-free condition. This example demonstrates that design can play a part in providing a stylish wheel cover that is capable of individualizing the bicycle to meet a wide variety of consumer tastes. 

The vehicle wheel of claim 13, wherein said wheel cover outer edge is attached by fixing said adhesive means to said spokes. 

Sulfur has long been known for its properties as a pesticide and a curative agent. Homer spoke of the pest-averting sulfur as far back as 800—1000 BC, Hippocrates (400 Bc) considered sulfur sa an antidote against plague, and Dioscorides (100 ad) used sulfur ointment in dermatology (244). In 1803, the use of a lime—sulfur protective treatment for fmit trees was reported, and in 1850 sulfur dust was used to protect foHage (245). In 1891 sulfur dust was used on soil to control onion smut (246). 

Close-Clearance Stirrers For some pseiidoplastic fluid systems stagnant fluid may be found next to the -essel walls in parts remote from propeller or turbine impellers. In such cases, an anchor impeller maybe used (Fig, 18-6), The fluid flow is principally circular or helical (see Fig, 18-7) in the direction of rotation of the anchor. Whether substantial axial or radial fluid motion also occurs depends on the fluid iscosity and the design of the upper blade-supporting spokes. Anchor agitators are used particularly to obtain irnpro ed heat transfer in high-consistency fluids,... 

Fig. 16.8. Part of tlie Stretham steam pumping engine. In the foreground are the crank and the lower end of the connecting rod. Also visible are the flywheel (with separate spokes and rim segments, all pegged together), the eccentric drive to the valve-gear and, in the background, an early treadle-driven lathe for on-the-spot repairs.

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