ENAMELS

Post 340 –by Gautam Shah

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An enamel is the hardest substance in the human body, in the form a cover on the teeth, consisting chiefly of calcium salts. Substances similar in hardness were produced through a glass-ceramic route. The word enamel derives from smelting or smelzan (German) or smalto (Italian), email (French and German), and enamel (English). Smelting as a process is very old, used for extracting metal by heat processing the mineral ore. Enamelling uses similar processes of material conversion.

10th C gold and enamel Byzantine icon of St Michael, St Mark Basilica

Enamel, is defined as a vitreous, glass like coating fused on to a metallic base. Through the history, enamels have been applied on gold, silver, copper, bronze and iron surfaces. The term is also used for many other applications that provide tough and a glossy surface such as the fusing of glass over glass, fired ceramics, and paints.

Enamel is formed from substance known as flux, frit or fondant. For enamelling the paste consisting of mixture of silica (from quartz or sand), soda or potash, and lead are deposited on to metal objects such as jewellery, small metal boxes, utensils, ceramics or glass, and fused by heat. The resultant surface is chemically identical to glass or highly vitrified ceramic, almost clear, with a slightly bluish or greenish tinge. The surface can be made opaque and coloured by the addition of other metallic oxides. When the temperature to fuse the materials is very high, the enamel formed is hard. Soft enamels are easy to produce and are more conventional.

Enamelled Signage

The brilliance of an enamel depends on the perfect combination of its ingredients and temperature. The colour is achieved by a change in the proportion of the ingredients of the flux than by an increase in quantity of the oxide.

Enamel Watch dial

The earliest known enamelled objects were made during the Mycenaean period during 13th C BC. Since then through history jewellery had applique colours of enamels. Arms’ handles and armour cases, mirrors, furniture handles, decorative dishes and bowls were embellished with enamel. Ceilings’ and doors’ metal panels were enamelled. Religious ceremony items such as cups, bowls, caskets, crosiers, were enamelled. Dials of table, pocket and wall clocks were adorned with enamelled numbers. In India jewellery and small boxes were enamelled, known as Minakari work.

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White Enamel ware Image from Public Pictures Domains.net

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With the onset of 18th C., Cast iron vessels for home and other uses began to be used. These enamelware were with little colour or patterns. The vessels with white enamel coating were known as white-ware. Hospital-ware such as gandy, urine pot, kidney tray, instruments’ tray, camping-ware and army-ware like tumbler, bowls, dishes, and public signages were made with enamelling. The white vitreous enamel linings, was also called porcelain. It was used for lining cooking stoves tops, oven doors, sinks and washbasin.

Stove -White Enamel goods

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There are two main methods of applying enamel to metal. Champlevé, in which hollows made in the metal surface are filled with enamel, and Cloisonné, in which strips of metal are applied to the metal surface, forming cells, which are then filled with enamel. With these two basic methods Six types of enamelling techniques have developed: These are Champlevé, Cloisonné, Basse-taille, Plique-à-jour, Encrusted, and Painted enamel.

Champlevé type 12th C armlet, so showing chased recesses for the enamel

1 Champlevé (French= raised field) enamels are done by scratching or etching a metal surface, usually copper, leaving hollows or troughs with raised lines between them. The hollows are filled with pulverized enamel and then fired. The hard-finished enamel is subsequently filed down until the glossy surface and the metal surface can be polished simultaneously, with crocus powder and jeweller’s rouge.

Cloisonné enamel plaque, Byzantine Empire, ca. 1100

2 Cloisonné (French= partitioned) processes, uses very small partitions, or cloisons, consisting of thin metal strips, built up on the surface of the metal. They may present a pattern and are fixed to the surface by the enamel. The Cloisonné technique is usually applied to silver, although gold or copper may also be used as bases. Cloisonné techniques originated in 4000 BC.

Basse-Taille type enamel Royal Gold Cup, 236 high x 178 across 14 C

3 Basse-Taille (French= low cutting) process is a kind of Champlevé but is applied to silver or gold. The metal is engraved or hammered to various depths according to the design. The depressions are then filled with translucent enamel, through which the design beneath it can be seen.

Silver-gilt set with plique á jour enamel plaques, and gold cell-work

4 Plique-à-jour (French=open braids) enamelling resembles cloisonne, but differs from it in that the partitions are soldered to each other rather than to the metal base, which is removed after firing. The remaining shell of translucent enamel gives the effect of stained glass. Plique-à-jour enamel is exceptionally fragile because it has no metal base.

Gold, encrusted (en ronde bosse) enamelling 1517

5 Encrusted Enamel or enamel en ronde bosse, involves the spreading of an opaque enamel paste over the slightly roughened surfaces of objects such as small figures.

Pocket Watch, 1750-1800, painted enamel portrait

6 Painted Enamels resemble small oil paintings. A metal plaque is covered with a layer of white enamel and fired. The design in coloured enamels, is then applied to the white ground, by painting, spraying, screen printing, or block printing, separate firing may be required for each colour because each may fuse at a different temperature. Painted enamelled miniature portraits were popular in Renaissance period.

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ELEVATORS or LIFTS

Post 339 – by Gautam Shah

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Elevators are intermittent transfer systems that moves goods and people in a direction perpendicular to the gravity. This is unlike the inclined stairs and escalators or almost parallel to the gravity systems like corridors, passages, roads, lanes and automated walkways. Elevator systems are modulated transfer systems in contrast to the uninterrupted transfer entities, and so have limited capacity of conveyance.

1 Well with bucket Ichijodani

The efficiency of a transfer system is determined by the fact whether the system is parallel, inclined or perpendicular to the gravity. The additional effort required to work against or towards the gravity, respectively retard or add to the efficiency.

2 Coal Miners- Everyday Life in a Midlands Colliery, England, UK, 19442 Miners Caged Bucket LiftThe intensity of transfer depends on whether the system operates continuously or intermittently. Continuous systems such as the escalators, automated walkways, conveyor belts, are governed by the speed of movement, while the intermittent systems such as the elevators, buses, railways are affected by the size capacity of the module, speed and frequency of service. Both systems, however have some traffic capacity limitations.

2 Old Selfridges Lift Wikipedia Image by Tony Hisgett from Birmingham, UK3 Elevator lobbyAn elevator system is capable of elevating or raising a load to a height. Lifting devices such as rope and a smooth axle were used to draw water from wells and lift building stones. The smooth axle was replaced by a wheel or pulley. The first documented proof of a lifting device is by Roman architect Vitruvius, who reports Archimedes (Greece 236 BC) building it. Ancient and medieval elevators used drive systems based on hoists or winders. These were inefficient methods. The use of a screw drive and multiple pulley systems, were the most important steps in lifting technology.

4 Scissor Lift Wikipedia Image by SmialElevators are manual, mechanical or power driven systems. Manual elevators are now used for small weights and low elevations. Manual elevators are free-fall and pulled or assisted-rise, or controlled fall-rise types. Some are partial combinations of both types, i.e. the rise may be free due to the counter weights, but fall may be controlled (such as dumb waitors from top floor kitchen facilities), or the system may work other way round. Fall is controlled by provision of a counter dead weight or parallel module. Mechanical grips that control the accelerations of speed during fall are also used. Fall is required to be controlled to avoid damage to the bucket or car module of the elevator, its resting place, noise due to impact, vibration during uncontrolled descent, spillage of liquid and breakage to fragile items like crockery etc. Fall is also required to be controlled so that stops match the required datum. Control of the rise is not very problematic in manual elevators, because there is no self acceleration during ascent. Rise of a weight (dead or a purposive load) to be elevated, is accurately controlled by the amount of energy expended. However some control mechanism to maintain the rise once gained, is required. Such dumb waitors are used between kitchen and serving areas, godowns and delivery areas, documents and spare parts transfer in commerce and industries.

4 Dumbwaiter geograph-4379493-by-Bill-Nicholls

Bucket-lifts were common for water wheels in India, Persia and many other countries. Bucket-lifts were also used to lift ore and coal from deep mines, and transfer miners. An air lift system works on a suction mechanism to transfer materials.

The classifications here are oversimplified discussions for the non technical people.

Mechanical Elevators use some form of chain pulley system or other devices to reduce the energy required. Such elevators are capable of lifting larger loads than dumb waitors. In some cases the elevators are designed as quasi mechanical systems, where rise is through a mechanical or power driven system, but the fall is natural but controlled. Such systems are used where, loads heavier than the manual capacity are to be lifted, power supply is erratic or not available, lifting requirements are occasional.

6 Mechanical Lift geograph-734490-by-Stephen-Sweeney

Power driven elevators are generally motorized, where an electric motor creates a hydraulic pressure or winds a traction rope to elevate a weight. These elevators work on DC current to regulate the start, speed and stop.

2 miners mechanical hoist

Hydraulic Elevators are not extensively used now, however, are ideal for low rise building where design limitations preclude overhead supports and machine rooms or load-bearing walls around lift well. The machine room can be located nearly anywhere, and let one maintain a flat roof line and save money on construction. Geared traction elevators are ideal for low-to medium-rise buildings, where high speeds are not essential, though speeds up to 400 ft/min. can be planned. Gear-less traction elevators are recommended for high-rise applications requiring the ultimate in service-speeds of 500ft/min and up.

Eiffel Tower Lift Cars

Passenger elevators are wide and shallow in depth, with centre-opening double doors or single side doors. Service-elevators, like for hospitals, are narrow and deep. Combination passenger and service elevators should be almost square. Freight elevators’ size and shape are determined by the dimensions of goods to be carried and by the loading / unloading methods used, but nominally allow carriage of 1200×2400 sheet materials.

Otis

While providing elevator system in a building, two basic norms are considered. The frequency and quantity of service required, and the quality of services desired. The quantity of services is determined by the passenger handling capacity during peak periods, while the quality of service is measured in terms of time required (waiting time) to avail a lift. The quality of elevator service is determined by the building planning, intensity of peak hour requirements, extent and duration of traffic, frequency and urgency of service required, type and control mechanisms, type of landing doors, etc.

Pan Pacific Singapore Open or Bubble elevators Wikipedia Image by SanchomOperation of lifts: Modern lifts have an electronically intelligent control system that actuates starting, stopping, door opening and closing, direction of motion, acceleration, speed and retardation, emergency smooth fall of the lift car. A variety of motors are used to power the lifts. The simplest is single speed resistant AC motors, the reduction gear is attached to the pulley, braking is semi mechanical, or through an additional motor, generally a DC motor. In a little more complex setup reduction gears are attached to the motor and a secondary winding is provided to stop the motor. More complex and accurate system consists of a DC motor. With DC motor input voltage can vary the output speeds, step-less gear system is often integral part of the motor. Such systems provide very high speeds, accurate stopping, less jerks and smooth operation.

11 Platform_window_cleaner

12 Bus Elevator for wheel chairs Image credits Aktron Wikimedia Commons.Elevators are prerequisite requirements for buildings taller than 3 floors. Elevators are often a legal requirement in public buildings because of wheelchair access laws.

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INTERIOR DESIGNER – the role

Post 338 – by Gautam Shah

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There is a common belief that Interior Design as a skill has originated from Architecture. This view gained strength from the fact that Architecture itself, as a unique skill branch, separated from the Building Engineering. Architecture, though, has facilitated other skills like Urban Design, Town Planning, Landscape Design. Interior Design as distinctive skill-based business has emerged due to distinctly different circumstances.

Firm of Herter Brothers, New York, (1864–1906), by Gustave and Christian Herter begun as an upholstery warehouse, became one of the first firms of furniture makers and interior decorators in the US after Civil War.

A building once constructed is initially readied for occupation by the original designer. However, buildings last for ages, and during the lifespan, must be altered and updated several times. Original building engineers or architects are unavailable or unwilling for such assignments. They do not have the income incentive for such ‘frivolity’. During early middle ages, or perhaps even earlier, low skilled ‘art -painters’ or artists’ assistants were hired to paint and decorate old buildings. The building decorators, worked along with their associate crafts-persons, like Iron smiths, Guilders, Glass blowers, Weavers, Embroiders, Rug and Carpet makers, Sculptors, Mural makers, etc. They would together undertake repairs, make furniture and update furnishings. These diverse services were coordinated by the Building Decorator. The services of decoration gradually emerged as a distinct business from Architecture or Building Engineering. The building decorator was neither a variant, nor subservient to the architect.

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The decorators worked as a facilitator, scheduling and coordinating the activities, while supervising the quality of various vendors. The services of the decorator were more frequently required for resetting the interior spaces, than for exterior updating. The interior decorator gradually began to offer design alternatives and devised specific design solutions. Interior decoration became a well-documented strategy, serving two basic purposes.

  1. It showed the user or client, in advance, the solution, in a representative form -a surrogate.
  2. It helped creation of a functional system by coordinating skills, materials and objects, sourced from different agencies.

Once the second objective was achieved without being continuously present on the site, it was possible for the Interior in charge person to devote more time and attention to the first objective.

The Interior decorator began to play a very active role of a professional interior designer, rather than being simply a site bound contractor. The Interior designer now operated from a Design Studio, usually located in an urban area. The studio was used for creating drawings, sketches, other presentations, models, pilots, prototypes, dummies, and cartoons (replicas of artwork in full size). It contained material-samples’ catalogs. The studio was a fixed location where clients, suppliers and crafts people were able to meet the Interior designer.

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The physical distancing of a studio from the site also separated the Design and Execution aspects of the interior practice. In the combined practice of Design + Execution, the need for a documented scheme was not very acute, as decisions immediately turned into actions. However, in pure (only) design practice, all decisions had to be not only communicated, but very often formally transmitted as an assignment to the site-based agency.

Schematic documentation of design of Interior work has been very difficult compared to Architecture or Building Engineering jobs. Amateur and untrained interior designers lack the capacity to document their design intentions, so prefer to work on the site, providing oral instructions to contractors or their workers. Many Interior Designers, even to day, where practicable would like to execute their work by themselves. The tradition of combining design + execution persists for many reasons:

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1.      Interior components require complex details and sensual materials. These are difficult to present through formal design documentation, and can be implemented only through personal involvement.

2.      Interior designing involves improvisation. The coordinated effect can be achieved, only when components or systems are substantially produced by the designers themselves.

3.      Interior design involves use of many crafts. Human resources and craftsmanship, unless fostered at home may not be available on required occasion.

Kimbel and Cabus was a Victorian-era furniture and decorative arts firm based in New York City.

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ARCHITECTURAL COATINGS -beginnings of OIL PAINTS

Post 337 –  by Gautam Shah 

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The art of Oil painting developed in Europe in the late Middle Ages. It was widely accepted as a better art medium, as it was easier to work with and allowed a greater variety of effects in comparison to the (than available) other media, like encaustic paint, tempera, water colour, fresco, etc. Oil painting dried relatively slowly with little change in colour. Tones are therefore easy to match, blend, or grade, and corrections easy to make. With this medium the painter was not limited to linear brush strokes, but could apply paint in glazes, washes, blobs, trickles, spray, or impasto (textured effect). The painter was no longer restricted to a prearranged design, as the slow drying system allowed change, improvisation and over work. Rich effects were possible with colours, tonal contrasts, and chiaroscuro (shading). Jan Van Eyck, a Flemish painter in early 15th C. explored the oil paint as medium to work over the tempera style of paintings. The Venetians took it the further with oil painting on canvas.

Women of Algiers Oil painting on Canvas 18 C

Alchemists shop with Concoctions

Early oil paints were made by modifying the drying oils like walnut or linseed with natural gums such as amber, copal, pine-rosin, etc. The oils were cooked, or exposed to air and sunlight. But later, cooking was conducted in closed kettles under pressure and in absence of oxygen. These ‘stand oils’ were modified with natural gums, resulting in viscous substance. The viscous substances were reduced (diluted) with turpentine.

Johannes Vermeer, The Milkmaid (1658–1660) Oil Paint

Modified drying oil mediums were found to be good for wood surfaces, unlike the tempera colours. The grains and texture of wood surfaces helped in binding the medium. It was also realized that the medium should have a better body (high viscosity compared to pure oil materials) and drying properties, otherwise would run (drip down).

Safflower oil as paint medium

art_supplies_artist_art_supplies_creative_color_paint_pastels-816166.jpg!dLéon_Bakst_-_Bathers_on_the_Lido._VeniceOILS AND OLEO-RESINOUS BINDERS

OILS: Vegetable oils and animal fats are the oldest binders known to man, some of which are still in use today. The suitability of an oil as a film forming substance depends on the highly unsaturated fatty acids. To make raw oils usable, three treatments are carried out 1. alkali refining to reduce the acidity and improve the colour, 2. kettle bodying -heating oils for a prolonged period at high temperatures to increase the viscosity and polymerizes it, 3. blowing air or oxygen through oil at elevated temperature to increase its oxidation.

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Types of Oils: Drying oils (Linseed oil, Tung oil -china wood oil, Dehydrated castor oil), Semi drying oils (Safflower oil, sunflower oil), and Non drying oils (olive, castor, cotton seed, coconut oil). For coatings drying oils and some semi drying oils are commonly used.

Flax plant to Linseed oil

Oils have been treated with many types of processes and substances. This included metallic salts. There were many problems with oil modified film forming substances. There was colour darkening of coating on ageing. It was not possible to create long lasting lighter colour shades. Over oxidation made the film very weak. Presence of natural gums made the film tacky in moist weather. The process of polymerization was not clearly understood.

resin-2290750_640OLEO-RESINOUS BINDERS: These substances are often combined with oils, bodied oils or their resins. Rosin is a low-cost resin derived from sap of mainly Pine trees (abietic acid). It is neutralized with lime (to form calcium Rosinate), glycerin (ester gum) or penta-erythritol (penta). These substances are now used in low cost paints and varnishes, or as cost effecting additives. Coumaro-indene (cumar) resins are derived from coal tar naphtha, and are used in leafing aluminum paints and other low cost systems. Phenolic resins are produced by reacting synthetic phenolics or phenolic compounds (cashew nut shell liquid) with formaldehyde.

Resins oozing out of a fresh cut in a tree

Gum Arabica

The technology of oil coating, in spite of its many drawbacks was very popular. It first came into being as the art media, but soon began to be used extensively in upgrading the interiors of mansions and palaces. It was the beginning of oil based architectural coating system.

Oil Paint work on Gopuram (Gate structure) of a Temple Chennai India

With the onset of industrial revolution the use of iron and ferrous alloys became extensive. Not only coating materials in large quantities, but for specific surfaces were now required. Rusting was a major problem with metal surfaces. Many protective coating systems were developed.

Semporna Sabah Multicoloured longhouse

During world war II, availability of natural oils such as linseed, castor, etc., which were of Asiatic and transatlantic origin, was affected. At the same time several petroleum-based products and derivatives began to be produced. These prompted research on non oil resins. Such chemically polymerized resins had faster drying time, better toughness, finer gloss and superior colour fastness, then heat bodied mediums. Polymeric resins both, thermo-plastic and thermo-setting varieties were produced.

ALKYD RESINS

Alkyd resins first came into use in the 1920s. These first alkyd resins (first polymerized polyester resins) were merely the reaction products of phthalic anhydride and glycerine. These products were too brittle to make a satisfactory film. The use of oils or unsaturated fatty acids in combination with the brittle alkyds resulted in the air-drying coatings which revolutionized the coating industry.

Architectural coatings

Alkyd resins form the basis of most of the commercially available glossy paints, flat paints and primers. These are produced by reacting drying and semi drying oils with a phthalic anhydride (acid), glycerin and penta-erythritol. Resins which have smaller proportion of oil -called short oil alkyds, or have oils of semi drying type, are used in baking finishes or as plasticizers. While long oil alkyds are used for air drying finishes or GP Enamels. Typically a long oil alkyd will take longer to dry out but may have higher strength, and a short oil alkyd may require baking to aid the drying.

Synthetic resin manufacturing through a complex plant

A variety of alkyds are produced by modifying them with other polymeric compounds. These modifiers are like: Rosinated alkyds, phenolated alkyds, styrenated alkyds, silicone modified alkyds, epoxy modified alkyds, acrylic modified alkyds, vinyl-toluene modified alkyds, and urethane alkyds.

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HEAT CAPACITY of BUILDINGS

HEAT CAPACITY of BUILDINGS

Post 336 ⇒   by Gautam Shah 

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Heat capacity is very important property of building materials. It is a dynamic property that is proportional to the size of the system, its mass, and how and when it flows in and out the material body. The building is affected how the materials constitute the shell, and what is the time relevance of the space in it. In other words, the shell and its space use both together determine Where and When the activities take place. The shell, the space and its environment also define How the activities flourish.

Heavy walls – lighter roof Nepal

Heat capacity or Thermal capacity, is a measure that reflects the ratio of the heat added or subtracted from an object, to the resulting temperature change. The heat capacity is divided by the amount of substance, mass, or volume, so that the quantity is independent of the size or extent of the entity. Specific heat is the heat capacity per unit mass of a material. In very simple terms heat capacity gets doubled, when the amount of substance of a body is doubled.

Stone walls and Thatched roof Machu Picchu

Specific heat capacity shows how much heat a body can store. So a building shell made up of materials with high specific heat capacity, high density, and thermal conductivity will function well, if it is occupied with a suitable space occupation and appropriate time scheduling of activities.

Thin body construction

Heat is conducted through various building elements, each having different capacity to store heat. Concrete and masonry have large capacity to heat. Wood is too slow in absorbing heat, but steel is very fast in warming up. Once the material object reaches certain level of heat storage, it begins to radiate the heat to the interior or exterior (or other adjoining entities) depending on the temperature conditions. On the exterior surface, if solar radiation and air temperatures are low, the heat will radiate to the outside. Alternatively, when interior conditions are comparatively cooler, the object will radiate heat on that face.

Thatched and terracotta tile roofs Heavy walls South India

Typically in a hot climate area a building with substantially heavy masonry and concrete begins to warm up after sunrise and continues to absorb heat till 1100 to 1500 hours (depending on the solar temperature, wall density, etc.). Thereafter it begins to radiate the heat to the interior side (as exterior side may remain warm till 1800 hours). One can stay indoors by allowing breeze to evacuate the heat through openings, or shift to indoor cooler sections, or outdoor shaded areas. One may not be able to use the interiors till about 2100 hours, or later till the roof and walls have cooled down. (The cooling of the shell occurs with release of heat on interior as well on exterior face).

Tin sheet Roofing (Cultybraggan_Camp)

This cycle could change in a thin body sheet roof or wall building. The structure gets warm very fast, often within 1 hour of sunrise, making it nearly impossible to stay indoors. The thin body structure, however, cools down within 1 hour of sunset time, allowing quicker reoccupation of the interior space.

Mix of enclosed and open spaces for activity scheduling

Very heavy body structures are economically not very viable. Heavy roof buildings (like stone, concrete, slate slabs, rammed earth terraces, etc.) are hazardous in earth quake prone zones. Thin body structures are faster to erect and economical. Light roof buildings (like of a tin or cement sheet, ceramic tiles, etc.) unless well framed get blown off in hurricanes.

Clay walls -Insulation Santa Fe

The heat exchange process in the interior side of a building primarily depends on the form (layout) and materials of the building and the external environment. It secondarily depends on the colour and texture of the external surfaces, size, location nature (glazed, solid, etc.), shading devices and placement of openings. It also depends on evaporation of water, heat generating elements like cooking hearth, lights, workshop equipments, and density of human occupation.

Courtyard house of South India

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GOUACHE

Post 335 – by Gautam Shah 

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Albrecht Dürer View of Nuremberg

Gouche art

Gouache is painting-technique using is water-soluble but opaque colours. It is different from art of water colours that are transparent. Gouache uses opaque colours that cover the white of the paper surface and as a result shows up as a denser colour effect.

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Mary Cassatt Portrait of the artist -Gouache

Gouache is a French-word, often spelled as guache pronounced –gwash, adopted from the Italian guazzo  or aguazzo, for ‘mud.’ Guazzo, a term originally applied to the early 16th C practice of applying oil paint over a tempera base. The term is now broadly used to describe any drawing made in body colour. A Body colour is any high viscosity water-soluble colour which also contains white pigments and extenders. (A white pigment has high refractive index whereas an extender like chalk has low refractive index or low covering capacity. An extender though adds the mass, and increases viscosity). As a white pigment, artists in 15th C used Lead white. Later during 19th C zinc oxide replaced the lead white.

Mughal Emperor Jahangir receiving his two sons Gouache on paper 1605-06

>Gouache by Victor Kirllovich Gaiduk

Fine bakery in the spa gardens of Kissingen ART by Adolph von Menzel 1893 Guache on Paper

Water colours need to be worked by laying darker colors on top of light. But in gouache the background, even if of darker colour can be painted first, and light colours, just as in oil painting, can be layered on top of it and that is less restrictive way to work.

Adolf Friedrich Erdmann von MenzelGouache colours use larger proportion of water soluble gum as the binder, than the art-water-colours. The binder was originally gum arabic, but now increasingly vinyl and acrylic emulsions are used. Gouache colours are used to create highlights in water colours. Aquapasto is a viscous thickening medium made of gum arabic and silica (now synthetic emulsions and gels), which is used to give an impasto effect (lit. =to knead dough) to add texture to water colour and gouache paintings.

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Blaas Eugene Portrait of a Lady -Gouache

Six circular gouache paintings of Hindu gods, 19th C

For gouache, the pigments are bound with glue and mixed with white pigment and extenders. Gauche, due to the opaque colourants, lacks the delicate luminosity of true water colour. Its colour massing is substantial, and with impasto effect can have a texture closer to oil-painting work. Gauche colours are water colours so dry to a lighter shade compared to oil Paints that dry to a darker shade. Gouache has widely used in the middle Ages for illuminated manuscripts. It became particularly popular in the 18th C. French painter François Boucher used it. In the 20th C. artists used gouache with impasto effect to create modern expressionistic effects. Modern Gouache is opaque water colour, popularly known as the poster colour. It is used for commercial art work such as posters, illustrations, comics, and 20th C animations.

Gouche Colours

Le_Théâtre_du_Châtelet,_Paris

Mikhail Filippovich -Illustration for Belarussian fairy tale

Modern Gouache colours

Poster colours for Gouache

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WHAT ONE CAN DO TO A MATERIAL ?

Post 334 – by Gautam Shah

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We seek material objects with perfect combination of Engineering attributes, Dimensional features and Surface properties. Our quest is further complicated when we require materials in very large quantity and consistent quality. We often need the materials locally and immediately. The quest for the materials proceeds along these courses.

Strategy –ONE

We usually have some idea how a particular material will function in a given situation. And so we SELECT the most appropriate material for its probable response. We primarily pick such materials off the surface of earth or mine it. But it would be very rare for anyone to find a Natural Material with perfect combination of all the essential qualities.

Natural pick up for a purpose

Adobe Building

Strategy –TWO

Natural materials have certain inherent efficiencies. We retain these, yet widen our options by dressing, cutting, and carrying out other modification processes. The size of a Modified Natural Material, remains the same or in most cases gets decreased. It is also not possible to achieve a material with distinctly different qualities, then what the nature offers.

Stone Implement

Kengo Kuma -Commune by the Great Wall of China

Strategy –THREE

Natural, modified (and often manufactured materials) have limitations of size, and variations of colour, texture, patterns, etc. One needs to assemble a larger entity. Agglomerated Materials are composed by closely placing the units with or without an alliance (exchange of ions), or by joining or adhering with an agent. The agglomerated materials also have a new variant, -the joint. The agglomerated entity remains as weak as its weakest constituent, usually the joint.

Log Cabin an assembly of natural material but joint always weak

Cain Natural material geometric assembly

Strategy –FOUR

Quality of natural, modified or agglomerated materials can be tempered with certain treatments and processes. The treatments are like annealing, hardening, seasoning, wetting, etching, ph balancing etc. Processed materials can have treatments that are surface bound or affect the whole body of the material.

Tempering a material

Strategy –FIVE

In spite of all the modifications, aggregation and processing the dimensional limitations of materials remain. An assured quality can only be achieved by producing a new material out of a raw material. Manufactured Materials are produced from raw materials that apparently have little or direct use. Manufacturing involves several levels of processing, before the resultant product can have some utility. Manufactured materials have completely different quality in comparison to their ingredients. Manufactured materials have some dimensional limitations, as imposed by the methods of manufacturing (batch size, machine capacity -eg. textiles, rexine, plywoods). Though, coatings and other deposition techniques overcome the size restraints.

Extruded Aluminum sections

Strategy –SIX

A manufactured-material is further processed to create Components, or several materials are mixed to form Compounded Material-Product. Natural and manufactured materials are also combined to create Composites (e.g. composites, co-extrusion), or chemically blended (co-polymerization) to form Synthetics. Components, compounded material-products, composites and synthetics, all are further exploited geometrically, to form Systems. Such systems have dual, Functional and Structural identities.

Stack_of_egg_cartons

Silicon carbide (SiC), also known as carborundum

The term Synthesis refers to how materials are made from naturally occurring or man-made chemicals. The term Processing means how materials are shaped into useful components to cause changes in the properties of different materials. –The science and Engineering of Materials : Askeland & Phule.

We primarily endeavour to create Single Material Objects. Single material-objects, be it natural or man-made have inherent efficiencies. We try to achieve the state of a single material efficiency by integrating (composites) or by synthesizing materials (synthetics). Such materials are commercially called multi purpose materials.

A Multi purpose material to be effective requires redefining of the geometry (form of construction) of the entity. Such redesign takes years of research effort. Human ingenuity, however, can outpace such attempts by inventing superior, but totally a different entity, for the given situation. The superiority of a newly invented entity may happen, because of its unitary structure, or as a multiplex system of simpler and lesser number of elements.

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BALUSTERS

BALUSTERS

Post 333 ⇒   by Gautam Shah 

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A baluster is a square or circular section shaft, traditionally made from wood or stone. Balusters are also made from hollow sections of metals, nowadays in extruded plastics or cast from cement concrete. Balusters are also called spindles, mid pickets, guards, or stair sticks.

Casa do raio Portugal

Balusters are used for forming a lattice in stair, gallery or terrace parapets. Full section and half section balusters are used as decorative elements on lower section of the wall and in furniture. Single baluster shafts, form a candlestick stand, column for supporting busts or stem of a chandelier.

Baluster

Balusters at the top edge are held by the coping or handrail of the parapet and at the bottom end by a runner base or are inserted into the step or floor. The entire assemblage of top rail, balusters and the bottom runner are known as the balustrade.

Baluster shapes -forms

The word Baluster =balaustra =pomegranate flower, derives from its shape resemblance to the swelling of a half-open pomegranate flower. Other words are balustre (French), balaustro (Italian), balaustium (Latin), balaustion (Greek). In India Balusters are also called Kumbhi or Lota (from Kumbha=pot).

Greek Amphora

Indian Lota or water pot

Many building codes require that opening within a parapet be of not more than 100 mm size. (There are three exceptions according to the 2003 International Building Code Section 1012.3, which allow openings not to exceed 200 or 500 mm, depending on occupancy groups or special areas.)

Chicago Cultural Center

The space between two balusters is equal to the width of the square base. A nominal tread width, may require two balusters. The second baluster in such cases is closer to the riser, and is taller than the first. This is done to maintain the mid bulge at the same level. It also allows the bottom part of decorative elements to be aligned with the tread, and the top elements are aligned with the railing angle. This, however, means the first and second balusters are not interchangeable and must be manufactured separately. Balusters without the horizontal decorative elements, with flutes or spirals patterns are interchangeable.

Gallery balustrade

Balusters have two basic configurations, top and bottom halves are mirrored forms, and other form has one elongated bulge with several rings at top and bottom. Other traditional baluster forms copy the Greek columns including the capital, or have fluted square column with a foliated capital. Stair and gallery balustrades need a proper turn around or ending. Balustrades could end to columns, building walls or more in a heavy newel post.

Baluster with bottom bulge

Double rows of balusters

The baluster, follow the wood turning styles and ceramic potters wheel shaping techniques. The form was copied in stone, metal, cement and plastic materials. Metals gave twisted fluting whereas plastics offered centre-less or off centric shapes.

Thin Sticks balusters

Balusters in Furniture

Assyrian palaces show window balusters in bas-relief. Balusters became very popular in Venetian buildings. The application to architecture was a feature of the early Renaissance. Giuliano da Sangallo has used balusters on the terrace at the Medici villa at Poggio a Caiano (1480 AD).

Verona Basilica di San Zeno Baluster in railing

Villa di poggio a caiano Balustrade Gallery

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EPOCH MAKING TECHNOLOGIES

EPOCH MAKING TECHNOLOGIES

Post 332 ⇒   by Gautam Shah 

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Mile stones of Human developments are marked by distinctive technological innovations that have given very competitive advantage to several fields. These through wide range of applications changed the course of developments.

History of prehistoric times is perceived in terms material related epochs. The era defining phrases such as Stone Age, Bronze Age, and Steel Age, are material related classifications. These distinctive material phases would not have happened without the fire, the most important of all conversion processes. Fire has been the mother of all the early processes of change. Cooking food with fire was the earliest conversion process. It showed the way to turn clay into ceramics. Conversion processes without the use of fire were as useful, such as agriculture, domestication of animals and construction of an abode.

Creating Fire and then use it for processing

Lighting a fire by Friction

Later periods of history, however, are recognized by different categories of technological achievements. Some of these were Deployment Technologies. A deployment technology shows how to things are formed, assembled, combined, handled or managed. Methods of joining, amalgamation and fabrication helped one to take up risks associated with new conditions and move from speculative conditions to guaranteeing the performance. It forced man to realize that it is advantageous to accept innovations, then to waste time and effort in fine tuning the current technology. Deployment methods are required to scale-up the experiment into an application of wider implications. Deployment methods have been used in executing extra ordinarily large structures like Dolmen or Stonehenge. Gothic structures rationalized the use of materials. The deployment methods were learnt from the nature which later developed in Biometric.

Assembling of different materials

Model of Da Vinci flying machine inspired by Flying Birds

Dolmen -Deployment of Technology

Wherever large deployment of resources by Humans occurs such as building sites, large human settlements, war zones, areas of natural calamities and diseases, recovery and reestablishment efforts were inevitable. These locations and structures thereon had to be abandoned wasting geopolitical advantage, or resurrect them by expending afresh. These Termination Processes (and reestablishment) were very important human opportunities requiring a rethink on relevance of technologies. Such opportunities were once considered unpredictable but modern day activities are planned with concerns like reuse, conservation, preservation, recycling, safe-disposal, cost-benefits, sustainability, etc.

Ecological concerns -Termination technology

Fire fighting -Termination technology

 World war II and later space travel offered challenges for new materials, products, ways of doing things and perspectives of concerns. Some of these are listed here:

Early computing machine

Miniaturization resulted from efficiency concern for mass-weight resulting in energy savings. In certain circumstances the loss of the second (width) and third (depth or height) dimension makes an entity of nearly zero mass such as in embedded transistors in a printed circuit, CCDs, metalized film, etc. Miniaturization has eliminated moving parts and has allowed distributed control systems. The distributed controls create components and subsystems that are replaceable.

Storage Device Pen Drive

Regulated processing conditions the response time, and in many circumstances recovery time. These technologies were used in controlling the reverse action, bounce back or impact absorption, but are used in transfer systems such as elevators, walkway, conveyers, controls for gadgets, vibratory conditions, acoustics, climate control, etc. It was once upon a time based on simultaneous or synchronous movement control, such as a turning shaft moved several sub systems through belts, sprockets, gears and levers. This is now a distributed control system with thyristor resulting in nearly a no-movement device.

Technologies begin to be relevant for a specific purpose, but others perceive it as a platform for a quantum jump. New materials come into being because new conversion processes offer the change. Deployment design is a challenge to use the technologies in different modes but termination processes re-validate the technologies for future.

constant speed propeller

Multi lateral or Multi functional operations are based on concurrent handling of several processes, in time and location. Such plants save space, often operate in inclement environmental conditions, isolation, hazard prone situations and require no ergonomic considerations. Some of the early multi functional technologies were CNC machines, work stations, Robotics, weaving looms, parallel computer processing, multi lateral servers, etc.

Laproscopic Surgery Robot

Convergent technologies combine several time and space relevant technologies. There is an inherent sequencing of processes or layering of applications. It begins as add on technologies to existing systems as and when these are realized or become viable. But soon enough someone somewhere innovates an integrated solution that has the efficiency of integrated working, fewer components, and a compact design. As these are offered as a fit-in replacement, so obviously have a neat and self-sufficient form.

Space vehicle technology that is being absorbed in automobiles

Tools, Handling, Reach capacities have made it possible to deploy new designs. This century some amazing tools like under water and argon welding, flexi drills, pneumatic tools and medical scopes, non invasive testing tools, remote processing and handling systems such drones, molecular level material removal and addition, 3D modelling and printing are available.

Space Foods getting into homes

Cross over absorption of technologies has become possible due to wide spread information dissemination. Innovations in a field have more takers in other fields. Space travel innovations have been very extensively adopted in life sciences, fine chemicals and agriculture. Advances in Bio-science have inspired builders to design biometric architecture. Digital imaging, remote sensing and global positioning have collectively opened many new avenues of knowledge. Miniaturization has brought in drones, bugs, spiders not just espionage tools, but monitors for conditions inside the body, pipes, atomic reactors, mines and architectural models. These are some examples how different technologies overlap to generate a new entity, which in turn is employed in never conceived form. A technocrat needs to be aware of emergent technologies in other fields. Otherwise by the time these percolate to their own fields, the developments outdate them.

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MOSAICS

Post 331 –by Gautam Shah

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640px-Cordoba_moschee_innen5_dome

Al-Hidaya Mosque, Seville, Spain

640px-Madaba_map

Mosaic is a surface assemblage of small pieces flat materials. The assemblage could be unintentional or natural, or a designed product. The designed product may reflect a pattern or a form. The image in mosaic emerges through the variations of textures, a tonal gradation within a colour range, multiplicity of colours and their boundaries, differences of surface reflectivity of the material pieces and most importantly through the flow of joints. The image also comes forth from the composition formed by the joints or spaces between the material pieces. The width, depth (or contour) and colour of the joint spaces could be uniform or varied.

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Rustic_calendar_from_Saint-Romain-en-Gal_(Autumn)

Sumerian Cone Mosaic Pergamonmuseum0116

Historically mosaics have been opaque, translucent or transparent ones, but modern technologies provide vivid mosaics. Vivid mosaics have variable transparencies and adjustable light emanating facilities. The light emanating mosaics have controllable intensities and tonal gradations. The cathode tubes, LCD and LED are examples of mosaic forming screens, but the same could be through a projected image on plain or crystal-activated screens.

Benches_at_Park_Guell_by_Antonio_Gaudi_(4209976058)central-library-unam-biblioteca-central-mosaic

Traditional mosaics were patterns and forms created from pieces of stones, ceramics, wood, glass, metals, leather and fabrics. The pieces were fixed to the base surface through a binding or cementing agent. Fabric and leather mosaics are created by stitching together the edges (patch work), whereas metal pieces were joined mechanically or fuse-welded at the edge, or with the base. Mosaic joints expose the base surface, the joining material or additional fill-in material. Mosaics are created by inlaying pieces of materials into a base through chasing, engraving, etc. For inlaying rare materials such as sea shells, precious stones, jewels, pearls, gold and silver etc. are used.

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640px-Roses_over_crossed_canes,_from_Museo_dell'Opificio_delle_Pietre_Dure,_Florence

Li_Jiang_Guesthouse

Romans have used bricks and stone masonry patterns as mosaics. Stone mosaics of Roman and later in Romanesque period exploited the marble debris of old buildings. Wood mosaics are used in floors and as marquetry in furniture and panelings. Ceramic mosaics have been popular everywhere, as the colour range vivid, glossy, permanent (non-fading) and different from any other material finishes. Glass mosaics were technologically closer to ceramics. Glass offered various levels of transparencies. Glass mosaics were created by joining specifically shaped pieces with lead cams. The pieces were coloured during glass manufacturing. The mosaic like effect is now created by painting with stained varnishes, often within marked areas. Mosaics’ patterns are also created by composite formation where fillers like stones, plastics, wood, etc. go into a matrix of a resin. Metal mosaics are created through alloying with a non miscible materials.

770px-Wood_mosaic

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