Chemistry: a mixture of particles (solid in a liquid, or liquid in a gas) in which the particles are finely dispersed at the macroscopic level, but remain undissolved. Suspensions will, given enough time, spontaneously separate into their components. Contrast with a solution, which is made up of dissolved particles, and which will not separate spontaneously.

A tool composers readily employ for harmonic color and to make a passage's phrasing more striking.

A suspension elongates an individual chord tone's duration past when the actual chord moves on to the next one. This technique is the main source of all dissonance on any accented beat in tonal music.

A suspension will have a preparation, being the tone that precedes the suspension.

The suspension is sometimes tied to it's preparation, sometimes not. The suspension ends in a resolution, or the tone following the suspension and lying a 2nd below it.

The preparation and resolution are usually chord tones.

A suspension is a form of a chord, in the notation Xsus(4|2)y, where X is the name of the chord, 4 or 2 is the subdivision of the suspension, and y is any extra change, for example, 7th chords.

Suspensions are chords composed of the root and the 5th of a chord, plus the 2nd or the 4th, depending on the kind of suspension. 2nds usually resolve to a V first inversion (for example, in D Major, C# E A). 4ths usually resolve to the root (using the previous example, D F# A). Another note: suspensions only very rarely resolve to minor chords, instead preferring major chords.

Suspensions are most commonly used in classical music to add tonal color and emphasis on a cadence in a piece of music, and can sometimes be found tied to the chord that comes after it, called the resolution, with the 3rd sometimes found, in this case, slurred (rhyme for the most part unintended).

In Jazz and modern music, suspensions take on a different role. In Pop and New Age, double-4ths are common (in C, C F Bb), which are just VII chords in first inversion. Another way to visualize this: C D G (the VII, in this case) is equal to D G C (the same chord in first inversion, which became a I 4-4). Anyway.

Jazz uses suspensions that do not resolve traditionally as well, as Major 2nds are not considered entirely dissonant in some styles, allowing musicians greater flexibility and the discovery of new and exciting chords.

Suspension is the part of an automobile (or other wheeled vehicle) which absorbs shock from the road (or other driving surface) by traveling vertically. This is generally performed using a system of lever arms and springs. Various types of auto suspension have various drawbacks and advantages. The original system of a sprung suspension, consisting of a fixed axle mounted on leaf springs, first used in horse-drawn carriages and wagons, is still in use today.

Basics

As a vehicle travels forward, it encounters variations in the road. Inertia causes the vehicle to want to continue heading as it has been heading, but the road's surface disagrees. The resulting force, applied to the tires, is translated into upward motion of the suspension. This upward motion is used to compress a spring, storing the energy, and pushing the suspension back down, or pushing the car up. The motion is both damped and limited by a shock absorber, or shock. These devices limit the maximum rate of compression, or closing of the suspension, and rebound, or opening. Without them, vehicles are sluggish during cornering and bounce around or lurch and roll over bumps and through dips.

Some of the more important characteristics of a suspension include travel, or the maximum vertical range of motion; compressing force, or spring rate, shown in foot-pounds or kg/mm; damping, provided by shock absorbers; camber, or the angle at which the wheel meets the ground, leaning sideways; caster, the angle at which the direction of suspension travel meets the ground, fronty to back; and toe, the angle at which a wheel points left or right. Of immense interest is deflection, or the degree of camber or toe change during suspension travel.

Automobiles

On various cars, only subsets of the suspension characteristics are typically adjustable. In particular, changing front camber and toe and rear camber only is what typically makes up an automotive alignment job, though all of those things affect handling. Camber is one of the most important, because during cornering, where handling matters the most, it can cancel or mitigate the effects of body roll. Finally, the unsprung mass or unsprung weight, the amount of mass which must travel up and down with the wheel. This gives the suspension member inertia which affects the rate at which it recovers from compression.

Fixed or Independent?

A suspension in which both wheels on an axle (IE, typically either front or rear) are independent of one another, is known as an independent suspension. If a fixed axle is used at all, it is most common for the front suspension to be independent and the rear to be a fixed axle, in which there is a literal solid axle between the wheels. This is the typical form for two wheel drive trucks, and just about every American car until the 1980s. However, especially in front wheel drive cars, there has been a drive towards independent rear suspension, or IRS, as it provides superior handling. This is actually cheaper and saves space in front wheel drive cars. It is desirable on all vehicles, however, for its superior handling characteristics.

Independent suspensions generally cost more to produce, but they are functionally better. There are a variety of independent suspension designs out there; The most common are the MacPherson strut suspension, double wishbone, multilink, and torsion beam designs. Double wishbone and multilink are arguably the best, and are used for the vast majority of sports and racing cars. A few cars (F1 and CART types sometimes use a bellcrank suspension in which the shocks are mounted horizontally to save vertical space, for aerodynamics reasons. There are also trailing arm, semi-trailing arm, and Weissach axle designs.

In general, independent suspension allows greater travel and improved handling, but fixed-axle type suspensions are cheaper and stronger. The greatest benefits of independent suspension are improved handling off-road and when the camber of the road changes. Fixed axle vehicles perform well in flat-road or -track scenarios and with hard suspension and sway bars to minimize body roll. However, they do not do particularly well anywhere else.

Springs

As far as the springs in suspension, they are generally one of two types; coil, or leaf. Leaf springs are several leaves of flexible metal; The further the vehicle is pressed down (or the suspension is pressed up) the more pieces of metal are bent (in some designs) or the further the bundle is bent; Either way, the resistance rises. You can get bolt-on spring limiters and helper springs to enhance leaf springs. Coil springs can be mounted around a shock or strut, or next to it. Furthermore, they can come as a single or progressive rate spring. Progressive rate springs have multiple rates twisted into them, and so will absorb short bounces without transmitting much force to the chassis. Some suspension systems use charged gas shocks, which actually support some of the load of the vehicle, but in general the entire weight of the vehicle rests upon the springs and the shock absorbers do nothing but damping.*

In fact, not all suspensions depend on springs to support the load. The 1957 Cadillac Eldorado Brougham utilized a compressor-driven air shock system using rubber diaphragms, and Citroen has famously produced air-operated suspension as well. This is the norm in bicycle suspension (see below) due to significant weight savings over a steel coil spring.

There are also active suspension systems. These use some sort of sensors and actuators to actively change some aspect of the suspension, whether it be ride height or damping levels. This is actually used for several purposes. Jeep developed a system that allowed one of their vehicles to literally drive over a foot-tall obstacle. Generally speaking, the sensors used for this type of active suspension are optical and use infrared light, though both sonar and radar can be used (and have been, in prototypes.) The actuators are typically hydraulic. The most common and inexpensive active suspension system is the air bag, heavy-duty examples of which are commonly installed in the rear of semi-tractor trucks. These compressor-driven systems resemble nothing more than a heavy-duty balloon, although they are sometimes enclosed in a canister for protection.

Another hydraulically-driven active suspension system is the Mercedes automatically leveling suspension. Found even on older vehicles (beginning in the seventies) this system uses a hydraulic valve connected to a lever on the rear sway bar to detect and compensate for excessive squat. As the suspension compresses, the sway bar rotates, thus the linkage moves and changes the valve position. A hydraulic pump attached to the engine runs to the valve in the back, which in turn runs to the rear suspension.

Finally, there is a third type of active suspension which lowers the vehicle at higher speeds in order to improve handling. The vehicle rises back up when you are going slower, in order to deal with speed bumps, curbs, and other road hazards.

Motorcycles

Motorcycles (two-wheeled vehicles) also feature suspension to enable them to track the road. Typically motorcycles have a rear wheel somewhat tightly integrated to the frame (attached with a single or double swing arm or in older models, not suspended at all) while the front wheel rests at the end of a fork with integrated springs and dampers. Motorcycles differ from cars in that they are tilted to steer, so the suspension forces are substantially different. Instead of the bearing on the wheel receiving a substantial sideways load, the tire must handle most of the force of cornering. Since they do not have two sides, motorcycles have neutral camber. However, the caster angle is of paramount importance, and controls the centering of the front wheel, which in turn leads the motorcycle to want to travel upright.

Most motorcycles have less than six inches of suspension travel front or rear, but dirt bikes and enduro motorcycles may have a foot or more in the front, and perhaps eight inches in the rear. The rear suspension of the motorcycle usually is sprung and damped with a coil-over unit between one or more rear swing arms and the upper rear frame, but variations have placed this shock in nearly every imaginable location, including horizontally under the seat, or even horizontally underneath the entire frame. Each approach has its own advantages, although it's hard to imagine a worse place for a component which can be damaged by rock impact than directly beneath the vehicle.

Bicycles

Since about the 1970s, bicycles have been produced which feature moving suspension parts. The earliest examples are undamped and use only a spring, which produces a bouncy ride. Still, it helps to absorb impacts. While some examples of even these early suspension bicycles have rear suspension, after these bicycles faded out and were replaced with "BMX" bicycles designed to be ridden over obstacles while standing, bicycle suspension first returned to the mass market in the form of front suspension on mountain bikes. Front-only suspension bikes are known as hardtails while full-suspension bikes are called softtails.

The front suspension of most modern bicycles is substantially similar to that of a motorcycle, differing only in scale. The longest-travel bicycle fork in production will compress about twelve inches, putting it well into motorcycle territory. Most forks only compress four inches at the outside, but some of your basic longer-travel examples have over six inches of motion. Most rear suspensions utilize a triangular arrangement which looks like it was lifted off of a typical hardtail bicycle, and whose shock travels forward to the lower tube, but there are notable examples including the ca. 2000 K2 Evo, which utilizes a motorcycle-style double rear swingarm.


* "Shock absorber" is actually a significant misnomer. The springs actually absorb the shock, although some of it is converted to heat when the medium inside the shock absorber (oil or gas) is forced through the narrow apertures that cause it to work. The shock absorbers are actually dampers (like a dash pot) in that they primarily limit the maximum rate of travel. Thus, they cause more shock to be transmitted through the suspension in exchange for preventing your car from constantly rocking and bouncing uncontrollably due to traveling over bumps.


References:

Website: Autozine Technical School (http://www.fortunecity.com/silverstone/lancia/58/technical_school/tech_index.htm)

If a student is "bad" enough they get punished by getting to stay out of school for a set number of days. Frequently imposed as a punishment for truancy and lateness; suspension certainly makes no logical sense.

Some school systems have begun what is called "in school suspension" where the student still comes to school but does not attend regular classes. The student is isolated in a room set aside for this purpose and left to do his/her schoolwork there.

(this is not an endorsement of the practice)
Suspension is a form of temporary body modification, or body play ritual, where a person is suspended in the air from flesh hooks which are placed in deep piercings. These piercings are usually made with traditional piercing needles, which are followed through with hooks. It is also possible, however, to create the piercings with the hooks themselves, as is often done in performances or in ritualized contexts. After the hooks are inserted, they are then attached with rope to a metal frame, or suspension rig, in a way such that the weight of the body is evenly distributed among the hooks.

The placement of these hooks on the body determines the style of suspension, and position of the body while suspended. The more hooks that are used, the less the pressure on each point. Thus, the use of several hooks can lend to a more comfortable suspension.

Suspension types inclue:

  • Suicide suspension: The most common style of suspension. The body is hung vertically from anywhere between one and six hooks placed across the upper back.


  • Chest suspension or O-kee-pa: Generally considered the most painful form of suspension, the body is hung vertically from one or more hooks placed across the chest. This is similar to the Native American rite referred to as "O-kee-pa". Many consider it disrespectful to refer to regular chest suspensions by this name, unless it is accompanied by the full set or rituals and intentions that are used in traditional O-kee-pa rituals. Many people may recognise this ritual from a scene in the movie A Man Called Horse


  • Superman suspension: The body is hung horizontally from several (usually ten) hooks placed along the back of the body, creating an effect which looks as if the suspendee is flying.


  • Coma suspension: The body is hung horizontally from several (usually ten) hooks placed along the front of the body, so the suspendee hangs face-up.


  • Lotus suspension: The body is hung in the yogic "lotus" position, or cross-legged, supported by hooks in the back and legs.


  • Tandem suspension: A form of suspension where a second person is suspended from hooks placed in another, already suspended person. In order to minimize cross-contamination, blood bowls are placed on the ropes between the two people, preventing any blood from travelling down the rope and contaminating the person on the bottom.


  • Variations: There are several variations to these positions which are accomplished by adjusting the position and number of hooks, or by adding additional ones.


While increasing in popularity, suspension is by no means a contemporary practice. Body suspension and other related body rituals have been perormed by various cultures for thousands of years.

There are several suspension groups operating throughout the world who facilitate suspensions for those interested, in a safe and controlled manner. Suspension group members are most often professionals in the body modification industry.

Suspension groups include: Rites of Passage, TSD, and I Was Cured.

There are several different reasons why people chose to suspend themselves. Some do it for the pure adrenaline or endorphin rush, and some do it for spiritual reasons, or as a rite of passage. Some choose to suspend in order reclaim control of their body, or to prove to themselves that they can overcome the limitations of pain and fear. Whatever the reason may be, most people choose to suspend for the experience, and what they learn about themselves from it.

Sus*pen"sion (?), n. [Cf. F. suspension, L. suspensio arched work, imperfect pronunciation. See Suspend.]

1.

The act of suspending, or the state of being suspended; pendency; as, suspension from a hook.

2.

Especially, temporary delay, interruption, or cessation

; as: (a)

Of labor, study, pain, etc.

(b)

Of decision, determination, judgment, etc.; as, to ask a suspension of judgment or opinion in view of evidence to be produced.

(c)

Of the payment of what is due; as, the suspension of a mercantile firm or of a bank.

(d)

Of punishment, or sentence of punishment.

(e)

Of a person in respect of the exercise of his office, powers, prerogative, etc.; as, the suspension of a student or of a clergyman.

(f)

Of the action or execution of law, etc.; as, the suspension of the habeas corpus act.

<-- # each of the above lettered definitions is elliptical; needs special handling for analysis. -->

3.

A conditional withholding, interruption, or delay; as, the suspension of a payment on the performance of a condition.

4.

The state of a solid when its particles are mixed with, but undissolved in, a fluid, and are capable of separation by straining; also, any substance in this state.

5. Rhet.

A keeping of the hearer in doubt and in attentive expectation of what is to follow, or of what is to be the inference or conclusion from the arguments or observations employed.

6. ScotsLaw

A stay or postponement of execution of a sentence condemnatory by means of letters of suspension granted on application to the lord ordinary.

7. Mus.

The prolongation of one or more tones of a chord into the chord which follows, thus producing a momentary discord, suspending the concord which the ear expects. Cf. Retardation.

Pleas in suspension Law, pleas which temporarily abate or suspend a suit. -- Points of suspension Mech., the points, as in the axis or beam of a balance, at which the weights act, or from which they are suspended. -- Suspension bridge, a bridge supported by chains, ropes, or wires, which usually pass over high piers or columns at each end, and are secured in the ground beyond. -- Suspension of arms Mil., a short truce or cessation of operations agreed on by the commanders of contending armies, as for burying the dead, making proposal for surrender or for peace, etc. -- Suspension scale, a scale in which the platform hangs suspended from the weighing apparatus instead of resting upon it.

Syn. -- Delay; interruption; intermission; stop.

 

© Webster 1913.

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