Civil Rights
Movements, leaders, victories and the continuing fight for equality.
q2K BHP
Black History Portal
THE BHP WIRE —
HIDDEN TRUTHS
What's New!
Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
Innovation, patents, science, technology and world-changing contributions.
Pioneers, champions, Negro Leagues, records, activism and excellence.
Meet the people whose lives, choices and achievements shaped the journey.
Black towns, communities, institutions and places where history happened.
Moments that changed communities, movements, institutions and the nation.
Wilmington, North Carolina once had a thriving Black middle class and an elected interracial government. In 1898 white supremacists used violence to overthrow that government, kill Black residents and drive many others from the city.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
A timing point, time point or timepoint is a public transit stop that a vehicle tries to reach at a scheduled time.[1] The vehicle should stay at timepoints and not supposed to pass until the schedule time has arrived. These stops are contrasted with all other stops on a scheduled route, for which the transit agency does not explicitly schedule an arrival/departure time. These other stops occur between timepoint stops, so their scheduled times are implicitly between those of the timepoints though not explicitly defined. At minimum, it allows regular passengers to estimate when a bus would get to a stop before or after a timepoint.
The creation of digital schedules, and real-time geo-located apps has somewhat complicated the situation for agencies operating with timepoints. These apps usually ingest GTFS (General Transit Feed Specification) data, a widely used schedule data format, which often include times for every single stop on a route. Agencies may interpolate between their timepoints, but this may not reflect a realistic expectation of when a vehicle should arrive, and the GTFS specification cautions against this practice.[2]
Whilst normal bus stops may interrupt a (painted) bike lane or a driveway may be blocked by a stopped bus, these features are not permissible for timing points.[3] A bus bulb, where buses stop in a traffic lane, is also not suitable for a timing point.[4]
 | This article about transport is a stub. You can help Wikipedia by adding missing information. |
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
A timing point, time point or timepoint is a public transit stop that a vehicle tries to reach at a scheduled time. The vehicle should stay at timepoints and not supposed to pass until the schedule time has arrived. These stops are contrasted with all other stops on a scheduled route, for which the transit agency does not explicitly schedule an arrival/departure time. These other stops occur between timepoint stops, so their scheduled times are implicitly between those of the timepoints though not explicitly defined. At minimum, it allows regular passengers to estimate when a bus would get to a stop before or after a timepoint. The creation of digital schedules, and real-time geo-located apps has somewhat complicated the situation for agencies operating with timepoints. These apps usually ingest GTFS (General Transit Feed Specification) data, a widely used schedule data format, which often include times for every single stop on a route. Agencies may interpolate between their timepoints, but this may not reflect a realistic expectation of when a vehicle should arrive, and the GTFS specification cautions against this practice. Whilst normal bus stops may interrupt a (painted) bike lane or a driveway may be blocked by a stopped bus, these features are not permissible for timing points. A bus bulb, where buses stop in a traffic lane, is also not suitable for a timing point.
A timing light is a stroboscope used to dynamically set the ignition timing of an Otto cycle or similar internal combustion engine equipped with a distributor. Modern electronically controlled passenger vehicle engines require use of a scan tool to display ignition timing. The timing light is connected to the ignition circuit and used to illuminate the timing marks on the engine's crankshaft pulley or flywheel, with the engine running. The apparent position of the marks, frozen by the stroboscopic effect, indicates the current timing of the spark in relation to piston position. A reference pointer is attached to the flywheel housing or other fixed point, and an engraved scale gives the offset between the spark time and the top dead centre position of the piston in the cylinder. The distributor can be rotated slightly until the reference pointer aligns with the specified point on the timing scale. Fuel-injected engines, or engines with microprocessor controls may require special procedures to allow basic spark timing to be observed without control effects from the engine computer. On most automotive engines, the timing is set based on the #1 cylinder. In few cases an engine is timed off another cylinder, such as the International Harvester V8 engines, which use #8, and the Isuzu 4Z series four-cylinder, which is timed off the #4 cylinder, or the 3 cylinder Saab two-stroke engine which is timed on the middle (#2) cylinder. Simple timing lights may just contain a neon lamp operated by the energy provided by the ignition circuit. Timing lights using xenon strobe lamps electronically triggered by the spark provide brighter light, allowing use of the timing lamp under normal shop lighting or daylight conditions. A timing light may be a self-contained instrument, but is sometimes combined with a voltmeter, RPM meter, and a dwell angle meter, or may be incorporated into a more comprehensive instrument such as an engine analyser. Self-contained units used to time automotive engines have an inductive pickup that clamps around the proper spark plug wire and serves as the trigger for the strobe. Power for the strobe comes directly from the vehicle's battery. Some older timing lights require the removal of the spark plug boot in order to attach a direct pickup between the wire's terminal and the centre conductor of the spark plug.
A timing mark is an indicator used for setting the timing of the ignition system of an engine, typically found on the crankshaft pulley (as pictured) or the flywheel. These have the largest radius rotating at crankshaft speed and therefore are the place where marks at one degree intervals will be furthest apart. On older engines, it is common to set the ignition timing using a timing light, which flashes in time with the ignition system (and hence engine rotation). Shining the light on the timing marks makes them appear stationary due to the stroboscopic effect. The ignition timing can then be adjusted to fire at the correct point in the engine's rotation, typically a few degrees before top dead centre and advancing with increasing engine speed. The timing can be adjusted by loosening and slightly rotating the distributor in its seat. Modern engines often use a crank sensor directly connected to the engine management system. The term can also be used to describe the tick marks along the length of an optical mark recognition sheet in order to confirm the location of the sheet as it passes through the reader. See, for example, U.S. Patent 3,218,439 (filed 1964, granted 1965), which refers to a timing track down the left side of the form, and U.S. Patent 3,267,258 (filed 1963, granted 1966), which refers to a column of timing marks on the right side of the form. The term can also be used to describe the timing patterns used in some barcodes, such as PostBar, Data Matrix, Aztec Code, etc.
In a spark ignition internal combustion engine, ignition timing is the timing, relative to the current piston position and crankshaft angle, of the release of a spark in the combustion chamber near the end of the compression stroke. The need for advancing (or retarding) the timing of the spark is because fuel does not completely burn the instant the spark fires. The combustion gases take a period of time to expand and the angular or rotational speed of the engine can lengthen or shorten the time frame in which the burning and expansion should occur. In a vast majority of cases, the angle will be described as a certain angle advanced before top dead center (BTDC). Advancing the spark BTDC means that the spark is energized prior to the point where the combustion chamber reaches its minimum size, since the purpose of the power stroke in the engine is to force the combustion chamber to expand. Sparks occurring after top dead center (ATDC) are usually counter-productive (producing wasted spark, back-fire, engine knock, etc.) unless there is need for a supplemental or continuing spark prior to the exhaust stroke. Setting the correct ignition timing is crucial in the performance of an engine. Sparks occurring too soon or too late in the engine cycle are often responsible for excessive vibrations and even engine damage. The ignition timing affects many variables including engine longevity, fuel economy, and engine power. Many variables also affect what the "best" timing is. Modern engines that are controlled in real time by an engine control unit use a computer to control the timing throughout the engine's RPM and load range. Older engines that use mechanical distributors rely on inertia (by using rotating weights and springs) and manifold vacuum in order to set the ignition timing throughout the engine's RPM and load range. Early cars required the driver to adjust timing via controls according to driving conditions, but this is now automated. There are many factors that influence proper ignition timing for a given engine. These include the timing of the intake valve(s) or fuel injector(s), the type of ignition system used, the type and condition of the spark plugs, the contents and impurities of the fuel, fuel temperature and pressure, engine speed and load, air and engine temperature, turbo boost pressure or intake air pressure, the components used in the ignition system, and the settings of the ignition system components. Usually, any major engine changes or upgrades will require a change to the ignition timing settings of the engine.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Joe Louis.
