The Nikon F6 is a 35 mm film single-lens reflex camera body manufactured by Nikon between 2004 and 2020. It was the sixth film camera in Nikon's 35mm F-series SLR line-up. Designed by Nikon, the model was manufactured at their Sendai plant.
27-878: The F6 was the most recent and final model in Nikon's F series. The model was discontinued in October 2020. It replaced the Nikon F5 , manufactured from 1996 to 2004. It can accept any Nikon F-mount lens with full metering functionality, excluding non-AI . At the time it was discontinued, the F6 was the last remaining film SLR still in production. [REDACTED] Media related to Nikon F6 at Wikimedia Commons Nikkorex F / Nikkor J Autofocus Camera | APS-format | Nikkorex with Leaf Shutter | Nikomat/Nikkormat | All Other Cameras | Manual Focus with electronic features (A mode) See also: Nikon DSLR cameras Model A model
54-427: A set of mathematical equations attempting to describe the workings of the atmosphere for the purpose of weather forecasting. It consists of concepts used to help understand or simulate a subject the model represents. Abstract or conceptual models are central to philosophy of science , as almost every scientific theory effectively embeds some kind of model of the physical or human sphere . In some sense,
81-400: A full sized vessel nearly so well as can be done for an aircraft or submarine—each of which operates entirely within one medium. Similitude is a term used widely in fracture mechanics relating to the strain life approach. Under given loading conditions the fatigue damage in an un-notched specimen is comparable to that of a notched specimen. Similitude suggests that the component fatigue life of
108-474: A larger fixed scale vertically when modelling topography to enhance a region's mountains. An architectural model permits visualization of internal relationships within the structure or external relationships of the structure to the environment. Another use is as a toy . Instrumented physical models are an effective way of investigating fluid flows for engineering design. Physical models are often coupled with computational fluid dynamics models to optimize
135-409: A noun, model has specific meanings in certain fields, derived from its original meaning of "structural design or layout ": A physical model (most commonly referred to simply as a model but in this context distinguished from a conceptual model ) is a smaller or larger physical representation of an object , person or system . The object being modelled may be small (e.g., an atom ) or large (e.g.,
162-401: A physical model "is always the reification of some conceptual model; the conceptual model is conceived ahead as the blueprint of the physical one", which is then constructed as conceived. Thus, the term refers to models that are formed after a conceptualization or generalization process. According to Herbert Stachowiak , a model is characterized by at least three properties: For example,
189-596: A street map is a model of the actual streets in a city (mapping), showing the course of the streets while leaving out, say, traffic signs and road markings (reduction), made for pedestrians and vehicle drivers for the purpose of finding one's way in the city (pragmatism). Additional properties have been proposed, like extension and distortion as well as validity . The American philosopher Michael Weisberg differentiates between concrete and mathematical models and proposes computer simulations (computational models) as their own class of models. Similitude Similitude
216-460: Is a concept applicable to the testing of engineering models . A model is said to have similitude with the real application if the two share geometric similarity, kinematic similarity and dynamic similarity. Similarity and similitude are interchangeable in this context. The term dynamic similitude is often used as a catch-all because it implies that geometric and kinematic similitude have already been met. Similitude's main application
243-501: Is achieved when testing conditions are created such that the test results are applicable to the real design. The following criteria are required to achieve similitude; To satisfy the above conditions the application is analyzed; It is often impossible to achieve strict similitude during a model test. The greater the departure from the application's operating conditions, the more difficult achieving similitude is. In these cases some aspects of similitude may be neglected, focusing on only
270-402: Is an informative representation of an object, person, or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin modulus , a measure. Models can be divided into physical models (e.g. a ship model or a fashion model) and abstract models (e.g. a set of mathematical equations describing the workings of
297-419: Is in hydraulic and aerospace engineering to test fluid flow conditions with scaled models. It is also the primary theory behind many textbook formulas in fluid mechanics . The concept of similitude is strongly tied to dimensional analysis . Engineering models are used to study complex fluid dynamics problems where calculations and computer simulations aren't reliable. Models are usually smaller than
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#1732852553658324-400: Is in validation of computer simulations with the ultimate goal of eliminating the need for physical models altogether. Another application of similitude is to replace the operating fluid with a different test fluid. Wind tunnels, for example, have trouble with air liquefying in certain conditions so helium is sometimes used. Other applications may operate in dangerous or expensive fluids so
351-475: The Solar System ) or life-size (e.g., a fashion model displaying clothes for similarly-built potential customers). The geometry of the model and the object it represents are often similar in the sense that one is a rescaling of the other. However, in many cases the similarity is only approximate or even intentionally distorted. Sometimes the distortion is systematic, e.g., a fixed scale horizontally and
378-418: The atmosphere for the purpose of weather forecasting). Abstract or conceptual models are central to philosophy of science . In scholarly research and applied science, a model should not be confused with a theory : while a model seeks only to represent reality with the purpose of better understanding or predicting the world, a theory is more ambitious in that it claims to be an explanation of reality. As
405-449: The design of equipment and processes. This includes external flow such as around buildings, vehicles, people, or hydraulic structures . Wind tunnel and water tunnel testing is often used for these design efforts. Instrumented physical models can also examine internal flows, for the design of ductwork systems, pollution control equipment, food processing machines, and mixing vessels. Transparent flow models are used in this case to observe
432-454: The detailed flow phenomenon. These models are scaled in terms of both geometry and important forces, for example, using Froude number or Reynolds number scaling (see Similitude ). In the pre-computer era, the UK economy was modelled with the hydraulic model MONIAC , to predict for example the effect of tax rises on employment. A conceptual model is a theoretical representation of a system, e.g.
459-451: The final design, but not always. Scale models allow testing of a design prior to building, and in many cases are a critical step in the development process. Construction of a scale model, however, must be accompanied by an analysis to determine what conditions it is tested under. While the geometry may be simply scaled, other parameters, such as pressure , temperature or the velocity and type of fluid may need to be altered. Similitude
486-415: The laborious task of dimensional analysis and formula derivation. Simplification of the formulas (by neglecting some aspects of similitude) is common, and needs to be reviewed by the engineer for each application. Similitude can be used to predict the performance of a new design based on data from an existing, similar design. In this case, the model is the existing design. Another use of similitude and models
513-504: The most important parameters. The design of marine vessels remains more of an art than a science in large part because dynamic similitude is especially difficult to attain for a vessel that is partially submerged: a ship is affected by wind forces in the air above it, by hydrodynamic forces within the water under it, and especially by wave motions at the interface between the water and the air. The scaling requirements for each of these phenomena differ, so models cannot replicate what happens to
540-433: The practical limitation, especially for laminated structures. Relaxing some of the scaling laws may eliminate the limitation of the design under complete similarity condition and yields the scaled models that are partially similar to their prototype. However, the design of the scaled structures under the partial similarity condition must follow a deliberate methodology to ensure the accuracy of the scaled structure in predicting
567-532: The pressure coefficient. This gives a required test velocity of: A model test is then conducted at that velocity and the force that is measured in the model ( F m o d e l {\displaystyle F_{model}} ) is then scaled to find the force that can be expected for the real application ( F a p p l i c a t i o n {\displaystyle F_{application}} ): The power P {\displaystyle P} in watts required by
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#1732852553658594-424: The scaled-down composite structures can be successfully carried out using the complete and partial similarities. In the design of the scaled structures under complete similarity condition, all the derived scaling laws must be satisfied between the model and prototype which yields the perfect similarity between the two scales. However, the design of a scaled-down structure which is perfectly similar to its prototype has
621-435: The submarine is then: Note that even though the model is scaled smaller, the water velocity needs to be increased for testing. This remarkable result shows how similitude in nature is often counterintuitive. Similitude has been well documented for a large number of engineering problems and is the basis of many textbook formulas and dimensionless quantities. These formulas and quantities are easy to use without having to repeat
648-680: The system are: This example has five independent variables and three fundamental units . The fundamental units are: meter , kilogram , second . Invoking the Buckingham π theorem shows that the system can be described with two dimensionless numbers and one independent variable. Dimensional analysis is used to rearrange the units to form the Reynolds number ( R e {\displaystyle R_{e}} ) and pressure coefficient ( C p {\displaystyle C_{p}} ). These dimensionless numbers account for all
675-411: The testing is carried out in a more convenient substitute. Some common applications of similitude and associated dimensionless numbers; Similitude analysis is a powerful engineering tool to design the scaled-down structures. Although both dimensional analysis and direct use of the governing equations may be used to derive the scaling laws, the latter results in more specific scaling laws. The design of
702-473: The two objects will also be similar. Consider a submarine modeled at 1/40th scale. The application operates in sea water at 0.5 °C, moving at 5 m/s. The model will be tested in fresh water at 20 °C. Find the power required for the submarine to operate at the stated speed. A free body diagram is constructed and the relevant relationships of force and velocity are formulated using techniques from continuum mechanics . The variables which describe
729-596: The variables listed above except F , which will be the test measurement. Since the dimensionless parameters will stay constant for both the test and the real application, they will be used to formulate scaling laws for the test. Scaling laws: The pressure ( p {\displaystyle p} ) is not one of the five variables, but the force ( F {\displaystyle F} ) is. The pressure difference (Δ p {\displaystyle p} ) has thus been replaced with ( F / L 2 {\displaystyle F/L^{2}} ) in
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