omniomni/omni-engineering huggingface dataset:
Bergen school (meteorology). The Bergen school of meteorology is a school of thought which is the basis for much of modern weather forecasting.

Founded by the meteorologist Prof. Vilhelm Bjerknes and his younger colleagues in 1917, the Bergen School attempts to define the motion of the atmosphere by means of the mathematics of interactions between hydro- and thermodynamics, some of which had originally been discovered or explained by Bjerknes himself, thus making mathematical predictions regarding the weather possible by systematic data analysis. Much of the work was done at the Geophysical Institute, University of Bergen, in Bergen, Norway.

The Bergen school was crucial in the early development and operationalization of numerical weather forecasting in the 1940s and 1950s, which was largely a cooperation between Scandinavian and US researchers. In this development, extant meteorological theories were synthesized. Due to the vast amount of calculations necessary for producing viable forecasts, the mathematical models were adapted to computer programs. The cross-Atlantic cooperations was also important to the development of the Bergen School and the Norwegian meteorology community

Bjerknes' assistants during the period 1917–1926 
Jacob Bjerknes
Halvor Solberg
Tor Bergeron
Carl-Gustaf Rossby
Sverre Petterssen
Erik Palmén
Erik Björkdal
Svein Rosseland
Carl Ludvig Godske
Johan Sandström

See also
Norwegian cyclone model
 Cyclogenesis
 Surface weather analysis
 Synoptic scale meteorology

References

 Vilhelm Bjerknes' Vision for Scientific Weather Prediction

External links
  Biography of Jacob Bjerknes by Arnt Eliassen with description of the School

Synoptic meteorology and weather
Meteorology in history
CropSyst. CropSyst is a multi-year multi-crop daily time-step crop simulation model being developed by a team at Washington State University's Department of Biological Systems Engineering. The model is used to study the effect of cropping systems management on productivity (budgeting).

The model has been parameterised for a wide range of crops such as potatoes, lentils, tea and grapes. Management options include rotations, irrigation, fertilization and tillage. It is widely used within research projects around the world including the United States, Italy and the United Kingdom (e.g. Land Allocation Decision Support System).

See also

Agrometeorology
Biological engineering
Crop yield

External links
Cropsyst Official web site
Department of Biological Systems Engineering.

Resources
Peer reviewed papers and applications of CropSyst can be found at:
SIPEAA
LADSS-CropSyst

Agricultural economics

Agronomy
Crops
Washington State University
Hans Monderman. Hans Monderman (19 November 1945 – 7 January 2008) was a Dutch road traffic engineer and innovator. He was recognised for radically challenging the criteria used to evaluate engineering solutions for street design. His work compelled transportation planners and highway engineers to look afresh at the way people and technology relate to each other.

His design approach is the concept of "shared space", an urban design approach that seeks to minimise demarcations between vehicle traffic and pedestrians, often by removing features such as kerbs, road surface markings, traffic signs, and regulations. Monderman found that the traffic efficiency and safety improved when the street and surrounding public space was redesigned to encourage each person to negotiate their movement directly with others.

Shared space 

Monderman took it as a given that for several generations, motorised traffic will remain an essential feature of European economies and their spatial fabric; in effect, he has taken this as his technical and policy target—a problem that simply will not go away. Against this background, he reviewed technologies and practices of street design, and stripped away those he felt insufficient or counterproductive. One of the better known of Monderman's accomplishments is the Dutch Woonerf, or "Living Street" project, which originated from a basically unplanned citizen initiative in Delft in 1968.

Career highlights 
 1969: Province of Friesland, civil engineer project leader infrastructure constructions and controller traffic safety
 1979 consultant traffic safety at Regional Traffic Safety Commission (accident analysis, road engineering, speed reduction measures); from then on developing and bringing into practise on several spots in Province of Friesland shared space approach
 1996 part-time traffic planner municipality of Smallingerland (Friesland)
 1999 to 2002 policy consultant province of Groningen (integration of traffic and landscape)
 2002 programme manager of integration programme (spatial, landscape, and traffic planning) in Drenthe

Honours
Monderman received an Honorary Doctor of Philosophy degree in traffic planning for outstanding achievements in the fields of traffic engineering, urban design, and project management.

In 2005 he was nominated for the World Technology Award for the Environment and gave a presentation on his work in a speech to the formal conference and awards ceremony in October 2005 in San Francisco.

References

External links
 A brief biography New Mobility Agenda
 About Shared Space Shared Space Institute, Drachten, The Netherlands
 Obituary in The Guardian
 "The Traffic Guru" by Tom Vanderbilt, The Wilson Quarterly

1945 births
2008 deaths
Sustainable transport pioneers
People from Leeuwarden
Deaths from prostate cancer
Dutch civil engineers
Trygve Reenskaug. Trygve Mikkjel Heyerdahl Reenskaug (21 June 1930 – 14 June 2024) was a Norwegian computer scientist and professor emeritus of the University of Oslo. He formulated the model–view–controller (MVC) pattern for graphical user interface (GUI) software design in 1979 while visiting the Xerox Palo Alto Research Center (PARC). His first major software project, "Autokon," produced a successful computer-aided design – computer-aided manufacturing (CAD/CAM) program which was first used in 1963, and continued in use by shipyards worldwide for more than 30 years.

Reenskaug described his early Smalltalk and object-oriented programming conceptual efforts as follows:

Reenskaug was extensively involved in research into object-oriented methods and developed the Object Oriented Role Analysis and Modeling (OOram) and the OOram tool in 1983. He founded the information technology company Taskon in 1986, which developed tools based on OOram. The OOram ideas matured and evolved substantially into the BabyUML project, which culminated in creating the data, context and interaction (DCI) paradigm.

Reenskaug wrote the book Working With Objects: The OOram Software Engineering Method with co-authors Per Wold and Odd Arild Lehne.
Later he wrote a virtual machine for Unified Modeling Language (UML). , he was professor emeritus of informatics at the University of Oslo.

Reenskaug died on 14 June 2024, at the age of 93.

References

External links

 
 
  (Part of an article entitled: "Beyond MVC: A new look at the Servlet Infrastructure")
 

1930 births
2024 deaths
Human–computer interaction researchers
Programming language designers
Norwegian computer programmers
20th-century Norwegian scientists
21st-century Norwegian scientists
Norwegian computer scientists
Norwegian company founders
Scientists at PARC (company)
John Butters. Sir John Henry Butters, CMG, MBE (23 December 188529 July 1969) was an Australian electrical engineer notable for his role in the Tasmanian Hydro-electric Department from 1914 to 1924, and as the head of the Federal Capital Commission, which developed Canberra between 1925 and 1930.

Biography
Butters was born in Hampshire, England, and trained as an electrical engineer at Hartley College, Southampton. He moved to Australia in 1909.

He is best known for his role as Chief Commissioner of the Federal Capital Commission. The FCC was active during the early expansion of the new federal capital, Canberra, and was successful in planning and building many significant buildings. For his role in the city's development he is sometimes referred to as the 'Founder of Canberra'.

Butters left Canberra in 1929 for Sydney, where he made a career as a consulting engineer, which continued until his retirement in 1954.

When he died, personal papers and diaries were not available, and the subsequent attempt at biography has proved difficult.

Honours
He was appointed a Member of the Order of the British Empire (MBE) on 19 October 1920, "in recognition of service during the war".

On 1 June 1923 he was made a Companion of the Order of St Michael and St George (CMG) for his work as Chief Engineer of the Tasmania Hydro-Electric Department.

On 8 July 1927, Butters was knighted to honour his work as Commissioner of the Federal Capital Commission.

Butters Drive in the Canberra suburb of Phillip is named in his honour. He was an inaugural inductee into the Canberra Engineering Hall of Fame.

John Butters Power Station in Tasmania is named after him.

The Butters Bridge in the Molonglo Valley, Canberra is also named after him and was opened in September 2016. It is the longest pedestrian bridge in the Southern Hemisphere.

Notes

References

 The Canberra Engineering Hall of Fame. 2004. Inaugural Inductees - 2002
Butters, John Henry (1885 - 1969)
https://web.archive.org/web/20080818051822/http://www.usyd.edu.au/alumni/about/vales/john_butters.shtml

1885 births
1969 deaths
Australian electrical engineers
Australian Knights Bachelor
Australian Members of the Order of the British Empire
Australian Companions of the Order of St Michael and St George
British emigrants to Australia
People of the Hydro-Electric Commission of Tasmania
Biotic potential. Biotic potential is described by the unrestricted growth of populations resulting in the maximum growth of that population.  
Biotic potential is the highest possible vital index of a species; therefore, when the species has its highest birthrate and lowest mortality rate.

Quantitative Expression

The biotic potential is the quantitative expression of the ability of a species to face natural selection in any environment. The main equilibrium of a particular population is described by the equation:

Number of Individuals = Biotic Potential/Resistance of the Environment (Biotic and Abiotic)

Chapman also relates to a "vital index", regarding a ratio to find the rate of surviving members of a species, whereas;
Vital Index = (number of births/number of deaths)*100.

Components

According to the ecologist R.N. Chapman (1928), the biotic potential could be divided into a reproductive and survival potential. The survival potential could in turn be divided into nutritive and protective potentials.

Reproductive potential (potential natality) is the upper limit to biotic potential in the absence of mortality. Survival potential is the reciprocal of mortality. Because reproductive potential does not account for the number of gametes surviving, survival potential is a necessary component of biotic potential. In the absence of mortality, biotic potential = reproductive potential.

Chapman also identified two additional components of nutritive and protective potentials as divisions of the survival potential. Nutritive potential is the ability to acquire and use food for growth and energy. Protective potential is described by the ability of the organism to protect itself against the dynamic forces of environment in order to insure successful reproduction and offspring.

Full expression of the biotic potential of an organism is restricted by environmental resistance, any condition that inhibits the increase in number of the population. It is generally only reached when environmental conditions are very favorable. A species reaching its biotic potential would exhibit exponential population growth and be said to have a high fertility, that is, how many offspring are produced per mother.

References

Reproduction
Reproductive ecology
Taipan Catamaran. Taipan Catamarans are sailing catamarans, available amateur built or manufactured by Australian High Performance Catamarans (AHPC).

Taipan 4.9
The Taipan 4.9 is either constructed professionally from kevlar/fibreglass or can be home built from plywood. Very few new boats are built with plywood nowadays. New fibreglass boats are only available from the current manufacturer, Concept Fibres, however amateur builders can buy plans to build a plywood boat.

It is a highly popular class in Australia, and is a favourite amongst high-performance racing purists. 

Designed by Greg Goodall And Jim Boyer in the early 1980s the 4.9 metre Taipan was a development of the Mosquito catamaran, lightweight and more similar to the A class in hull design. The sail plan had a higher aspect, and it was lighter overall weight than most North American designs. Rigged and ready to sail the 4.9 weighs a minimum of 231 lb (102   kg). Other features include a wing mast, and later on a spinnaker. The spinnaker has been abandoned among the most competitive racing fleets as the benefit it confers is minimal. Like the Mosquito and Cobra class rules allow to sail the boat cat rigged or sloop rigged.

Class rules were changed in 2019 to allow the use of carbon fibre in construction. 

Taipans are raced at many Sailing Clubs, especially on the east and south coast of Australia. Westernport Yacht  Club currently has the strongest fleet. Many top-tier (e.g Glenn Ashby) sailors have been active in the Taipan class throughout its history.

Specifications
Length   4.95 m (16 ft 2 in)
Beam     2.34 m (7 ft 8 in)
Mast (H) 8.5 m (27 ft 9 in)
Weight rigged   105 kg (231 lb)
Sail area – main   14 m2 (147 ft2)
Jib   4.2 m2 (45 ft2)
Spinnaker   17.5 m2 (188 ft2)
Crew 1 (cat rigged) or 2 (sloop rigged)

Taipan 5.7 
The "bigger" Taipan 5.7 was designed with the same principles as the 4.9 but made for a larger crew. A crew weight of 350–375 lb (160–170 kg) two adult males is the optimal crew for this 5.7-metre (18 ft 8 in) catamaran.  With canted, hulls, heavier wing mast, spinnaker, daggerboards & rudders, this 275 lb (135 kg) catamaran was similar in performance to the Stingray Mk2 and later Nacra 5.8 catamarans. Production of the Taipan 5.7 model was discontinued by AHPC in 2004.

Specifications

Length   5.7 m (18 ft 8 in)
Beam     2.5 m (8 ft 2 in)
Mast (H) 9.5 m (31 ft 3 in)
Total sail area 23.3 m2 (251 ft2)
with spinnaker 46.3 m2 (498 ft2)
Main 16.1 m2 (173 ft2)
Jib 5.3 m2 (57 ft2)
Spinnaker 23 m2 (247 in)
Mast 1.9 m2 (20 in)
Mast dimensions 160 × 74 mm
Approx rigged weight 135 kg (270 lb)
Crew – two

External links
 http://www.taipan.asn.au/
http://www.ahpc.com.au/

Catamarans
Castigliano's method. Castigliano's method, named after Carlo Alberto Castigliano, is a method for determining the displacements of a linear-elastic system based on the partial derivatives  of the energy. He is known for his two theorems. The basic concept may be easy to understand by recalling that a change in energy is equal to the causing force times the resulting displacement. Therefore, the causing force is equal to the change in energy divided by the resulting displacement. Alternatively, the resulting displacement is equal to the change in energy divided by the causing force. Partial derivatives are needed to relate causing forces and resulting displacements to the change in energy.

Examples
For a thin, straight cantilever beam with a load P at the end, the displacement  at the end can be found by Castigliano's second theorem :

where  is Young's modulus,  is the second moment of area of the cross-section, and   is the expression for the internal moment at a point at distance  from the end. The integral evaluates to:

The result is the standard formula given for cantilever beams under end loads.

Castigliano's theorems apply if the strain energy is finite. This is true if . It is  the order of the energy (= the highest derivative in the energy), , is the index of the Dirac delta (single force,  ) and  is the dimension of the space. To second order equations, , belong two Dirac deltas, , force and , dislocation and to fourth order equations, , four Dirac deltas,  force,  moment,  bend,  dislocation.
 
Example: If a plate, , is loaded with a single force, , the inequality is not valid, , also not in , . Nor does it apply to a membrane (Laplace), , or a Reissner-Mindlin plate, . In general Castigliano's theorems do not apply to  and  problems. The exception is the Kirchhoff plate, , since . But a moment, , causes the energy of a Kirchhoff plate to overflow, . In  problems the strain energy is finite if . 
 
Menabrea's theorem is subject to the same restriction. It needs that 2 is valid. It is  the order of the support reaction, single force , moment . Except for a Kirchhoff plate and  (single force as support reaction), it is generally not valid in  and  because the presence of point supports results in infinitely large energy.

External links
 Carlo Alberto Castigliano
 Castigliano's method: some examples

References

Beam theory
Eponymous theorems of physics
Structural analysis
Paper composite panels. Paper composite panels are a phenolic resin/cellulose composite material made from partially recycled paper and phenolic resin. Multiple layers of paper are soaked in phenolic resin, then molded and baked into net shape in a heated form or press.  Originally distributed as a commercial kitchen surface in the 1950s, it has recently been adapted for use in skateboard parks as well as various other applications, such as residential counters, cabinetry, fiberglass cores, guitar fingerboards, signage, exterior wall cladding, and a variety of architectural applications.

Composition 
There are several manufacturers in North America who use a different composition of materials to form the final product.  One composition is cellulose fiber and phenolic resin (a type of polymer) which is combined and baked for a smooth hard surface.  The natural fibers are made from plant, animal and mineral sources. However most natural fibers are predominantly cellulosic.

 Cellulose derived from tree pulp is turned into large rolls of paper. 
 The paper is then soaked in  phenolic resin and goes up to a heating chamber to be dried out before being rolled back up. 
 Then hundreds of these sheets are laid on top of each other and with the use of compression molding the stack is compacted. 
Because of the resin's thermoset properties the resulting cooled material is hard.

Applications 

It was used for the Boeing 747 for their air tables, hydroforming dyes, vacuum chuck faces, work holders, and proofing materials. Architecturally, it is used for countertops. It has also been used for whaleboard in fiberglass boat building. Other commercial uses include cutting boards, prep tables, pizza peels, and the dashboard of a pickup truck prototype vehicle.

Since the last quarter of the 20th century, phenolic resin and cellulose based compound materials have been used as an alternative to ebony and rosewood to make stringed instrument fingerboards. From 2012 to 2018 guitarmaker Gibson used Richlite, a paper composite material, for the fingerboard on several top-of-the-line production guitars.

Properties 

Even if it is formed by laminating many layers of paper together, the finished material appears as a solid, and is not considered to be a sandwich panel. Resistance to high temperatures has been claimed to be up to 350 °F.

See also 

 Micarta, a group of similar materials, especially if made with paper and epoxy resin.
 Ebonol, a paper and phenolic resin compound sometimes used for fingerboards in stringed instruments.

References

External links 
Richlite Company home page
Eco-Clad home page

Materials
Copper loss. Copper loss is the term often given to heat produced by electrical currents in the conductors of transformer windings, or other electrical devices. Copper losses are an undesirable transfer of energy, as are core losses, which result from induced currents in adjacent components. The term is applied regardless of whether the windings are made of copper or another conductor, such as aluminium. Hence the term winding loss is often preferred.  The term load loss is used in electricity delivery to describe the portion of the electricity lost between the generator and the consumer that is related to the load power (is proportional to the square thereof), as opposed to the no-load loss.

Calculations
Copper losses result from Joule heating and so are also referred to as "I squared R losses", in reference to Joule's First Law. This states that the energy lost each second, or power, increases as the square of the current through the windings and in proportion to the electrical resistance of the conductors.

where I is the current flowing in the conductor and R is the resistance of the conductor. With I in amperes and R in ohms, the calculated power loss is given in watts.

Joule heating has a coefficient of performance of 1.0, meaning that every 1 watt of electrical power is converted to 1 Joule of heat. Therefore, the energy lost due to copper loss is:

where t is the time in seconds the current is maintained.

Effect of frequency
For low-frequency applications, the power loss can be minimized by employing conductors with a large cross-sectional area, made from low-resistivity metals.

With high-frequency currents, the proximity effect and skin effect cause the current to be unevenly distributed across the conductor, increasing its effective resistance, and making loss calculations more difficult.

Litz wire is a type of wire constructed to force the current to be distributed uniformly, thereby reducing Joule heating.

Reducing copper loss
Among other measures, the electrical energy efficiency of a typical industrial induction motor can be improved by reducing the electrical losses in the stator windings (e.g., by increasing the cross-sectional area of the conductor, improving the winding technique, and using materials with higher electrical conductivity, such as copper). In power transmission, voltage is stepped up to reduce current thereby reducing power loss.

References

Sources

External links
 Reduction of copper losses

Electric transformers
Electrical engineering