S

SI – The International System of Units (abbreviated SI, from the French Système international d’unités) is the metric system used in science, industry, and medicine.

The International System of Units (SI), commonly known as the metric system, is the international standard for measurement. The International Treaty of the Meter was signed in Paris on May 20, 1875 by seventeen countries, including the United States and is now celebrated around the globe as World Metrology Day .

SI unit is an international system of measurements that are used universally in technical and scientific research to avoid the confusion with the units. Having a standard unit system is important because it helps the entire world to understand the measurements in one set of unit system.

SCORCH– To scorch is to burn something fiercely, to the point where its surface — your face, prairie grass, a steak on the grill — chars or otherwise changes color. Although scorch usually refers to burning something (whether it’s the sun or a blowtorch doing the burning), that’s not always the case.

Scorch has a quite specific meaning in rubber technology where it is the term for premature vulcanisation of the mix before the final shaping can be accomplished. Scorch inhibits flow and results in scrap. Since the raw polymers are highly viscous, the work required for mixing generates substantial heat.

SCREW– The definition of a screw is a piece of metal with a threaded surface and a point on one end and a slotted head that is twisted to penetrate and fasten two things together. An example of a screw is the pointy piece of metal you use to attach shelves to a wall.

The screw is really a twisted inclined plane. … Some examples of the uses of a screw are in a jar lid, a drill, a bolt, a light bulb, faucets, bottle caps and ball point pens. Circular stairways are also a form of a screw. Another use of the screw is in a device known as a screw pump.

SERVICE TEST– A test of an item, system of materiel, or technique conducted under simulated or actual operational conditions to determine whether the specified military requirements or characteristics are satisfied.

Service Level Testing includes testing the component for functionality, security, performance and interoperability. Each and Every Service needs to be first tested independently. 5) Functional Testing. Functional Testing should be done on each service to. Ensure that service delivers the right response to each request.

SET– set·ting. to put (something or someone) in a particular place: to set a vase on a table. to place in a particular position or posture: Set the baby on his feet. to place in some relation to something or someone: We set a supervisor over the new workers.

SET UP – When a stock is said to be “set up,” it has scorched, and vulcanization has started. It can no longer be processed smoothly.

SHEET MOLDING COMPOUND– Sheet Molding Compound (SMC) is a compression molding compound often used for larger parts where higher mechanical strength is needed. SMC is a fiber reinforced thermoset material.

Sheet molding compound (SMC) resin is a fiberglass-based compression molding that is used in applications that require high strength.

Dough moulding compound (DMC) is an uncured dough-like thermoset compound used to make glass reinforced plastic (GRP) products. It is formed into products by compression moulding. … The heated plug and mould softens the DMC and allows it to flow into the mould cavities.

SHELF AGING– Shelf life can be defined as a finite length of time after production (in some cases after maturation or aging) and packaging during which the food product retains a required level of quality under well-defined storage conditions (Nicoli and Calligaris, 2018).

SHELF LIFE– Once the ambient cure temperature is reached and the cross-linking reaction … Shelf-life is a valuable property to incorporate into a tissue-engineered product.

• The environmental factors which influence shelf life are:
• Temperature – decomposition of active drug ingredient takes place at a faster rate with rise in temperature.
• Humidity – an increase in humidity levels leads to crust formation on tablets due to increased oxidation by air.

SHORE HARDNESS– Shore (Durometer) Hardness is a measure of the resistance a material has to indentation. Named after its inventor, Albert Ferdinand Shore, Shore hardness offers different scales for measuring the solidity of different materials. … In this instance, the Shore A and Shore D scales will briefly overlap.

Shore Hardness is a measure of the resistance a material has to indentation. There are different Shore Hardness scales for measuring the hardness of different materials (soft rubbers, rigid plastics, and supersoft gels, for example).

The Shore A Hardness Scale measures the hardness of flexible mold rubbers that range in hardness from very soft and flexible, to medium and somewhat flexible, to hard with almost no flexibility at all. Semi-rigid plastics can also be measured on the high end of the Shore A Scale.

Shore hardness is measured with a device known as a Durometer, hence the term ‘Durometer hardness’.

SILICONE RUBBER– Silicone rubber is used in automotive applications, many cooking, baking, and food storage products, apparel including undergarments, sportswear, and footwear, electronics, to home repair and hardware, and a host of unseen applications.

Silicone is identified as a synthetic elastomer as it is a polymer which displays viscoelasticity – that is to say it shows both viscosity and elasticity. Colloquially people call these elastic characteristics rubber. Silicone itself is made up of carbon, hydrogen, oxygen and silicon.

Silicone is more expensive than most rubber types because it is a speciality high performance polymer with outstanding qualities. It is made in relatively low quantities and requires expensive and complicated primary manufacturing facilities.

SINK MARK– A Sink Mark can be defined as a depression, resembling a dimple or groove, caused by excessive localized shrinking of the material after the part has cooled. … This is displayed as sink marks.

Sink Marks are areas in a molded part where the surface is deformed into a depression. The depressions typically occur in areas of thick geometry and are caused by uneven cooling of the injection material. … Luckily, there are many ways to alleviate issues cause by sink marks, including modifying the geometry.

SKIM COAT– A skim coat, also known as a level-five drywall finish, is a thin coat of diluted joint compound that can be applied by hand, paint roller or spray rig. … It’s an easy way to create flat and uniform surfaces on walls and ceilings so they can be painted or re-textured.

Skim coating can be a time-consuming process, and it isn’t always necessary. It’s especially desirable in areas of critical lighting, such as the upper parts of walls under a skylight or a hallway with a light source that shines obliquely on the walls.

The cost to skim coat can range from around $1.10 to $1.30 per square foot not including new gypsum board. Overall, it could cost anywhere between $464 to $569 to skim coat your entire home, depending on the size and amount of labor required.

SKIN – The skin is composed of two main layers: the epidermis, made of closely packed epithelial cells, and the dermis, made of dense, irregular connective tissue that houses blood vessels, hair follicles, sweat glands, and other structures.

The epidermis has three main types of cell: Keratinocytes (skin cells) Melanocytes (pigment-producing cells) Langerhans cells (immune cells).

Skin has three layers:

• The epidermis, the outermost layer of skin, provides a waterproof barrier and creates our skin tone.
• The dermis, beneath the epidermis, contains tough connective tissue, hair follicles, and sweat glands.
• The deeper subcutaneous tissue (hypodermis) is made of fat and connective tissue.

SOAPSTONE – Soapstone (also known as steatite or soaprock) is a talc-schist, which is a type of metamorphic rock. … It is produced by dynamothermal metamorphism and metasomatism, which occur in the zones where tectonic plates are subducted, changing rocks by heat and pressure, with influx of fluids, but without melting.

Soapstone is used for sculpture, tile, and kitchen countertops, sinks, wall tile and even for woodstoves and fireplaces.

Soapstone is commonly believed to have a soothing, balancing effect while creating a positive, calming energy. Soapstone is valued for it the way it helps one prepare for changes in life. It is also thought to promote truth, logic as well as rational and creative thinking.

SPECIFIC GRAVITY– Urinary specific gravity (SG) is a measure of the concentration of solutes in the urine. It measures the ratio of urine density compared with water density and provides information on the kidney’s ability to concentrate urine. A urinary specific gravity measurement is a routine part of urinalysis.

the ratio of the density of a substance to the density of some substance (such as pure water) taken as a standard when both densities are obtained by weighing in air.

SPECIFIC VOLUME– Specific volume is defined as the number of cubic meters occupied by one kilogram of matter. It is the ratio of a material’s volume to its mass, which is the same as the reciprocal of its density. In other words, specific volume is inversely proportional to density.

Specific volume equals volume divided by mass. Typically, volume is measured in cubic meters (m3), and mass is measured in kilograms. Specific volume is then calculated as volume divided by mass.

SPRUE – A sprue is a large diameter channel through which the material enters the mould. A runner is a smaller diameter channel that directs the molten metal is directed towards the individual part (particularly common when casting multiple parts at once).

1. The waste piece on a casting (as of metal or plastic) left by the hole through which the mold was filled.
2. The hole in which a sprue forms. sprue.

The name sprue derives from a Dutch word describing inflammation of the mouth, which is a frequent symptom.

SPRUE MARK– The sprue is a large-diameter channel through which plastic flows, usually around the edges of the part or along straight lines. … The gate is the location at which the molten plastic enters the mold cavity and is often evidenced by a small nub or projection (the “gate mark”) on the molded piece.

All fire marks have a “casting mark,” which is the rough area where the molten iron was either poured directly into the mold cavity or flowed, through channels in the sand, into the mold cavity. In casting, the “sprue” refers to the hole and passage through which the molten iron, or “meld,” is poured into the mold.

The name sprue derives from a Dutch word describing inflammation of the mouth, which is a frequent symptom.

STABILIZER– In industrial chemistry, a stabilizer or stabiliser is a chemical that is used to prevent degradation.

What is a Stabilizer. At its most basic, a stabilizer is any substance that is used to preserve the physical and chemical properties of a material and prevent degradation. At a chemical level, these stabilizers work by inhibiting chemical reactions.

A stabiliser is an additive to food which helps to preserve its structure. … The following hydrocolloids are the most common ones used as stabilisers: alginate. agar. carrageen.

Stabilizers, naturally. The formulation of natural food products includes the use of plant sourced gums and starches as natural stabilizers. … In formulating natural food products, gums and starches isolated from plant sources are widely used as stabilizers.

STATE OF CURE– The state of cure at the end of rubber parts moulding determines the essential of the parts properties [1]. Rubber material mainly consists of long polymer chains. In the uncured state, under mechanical stress, relative chains sliding is possible: the material has a plastic behaviour.

curing – the process of becoming hard or solid by cooling or drying or crystallization; “the hardening of concrete”; “he tested the set of the glue” solidification, solidifying, hardening, set.

The degree of curing describes the conversion achieved during crosslinking reactions (curing). Linkage can be achieved either by direct setup of macromolecules or reaction to the already existing polymers. … This can easily be measured by means of differential scanning calorimetry (DSC).

A curing agent can be defined as a substance able to participate in the chemical reaction between the oligomer, pre-polymer and polymer, to achieve the polymerization process and provide the final film.

STEAM CURE (Open)– Open molding is a low cost and effective method to manufacture composites. Open mold processes include, spray-up (chopping) and hand lay-up. … In this process, a single-sided mold is used that acts as the form and cosmetic surface of the part. Gel coat is applied to the prepared mold surface.

An open mold is a container, like a cup, that has only the shape of the desired part. The molten material is poured directly into the mold cavity which is exposed to the open environment. Figure:1. This type of mold is rarely used in manufacturing production, particularly for metal castings of any level of quality.

Hand lay-up is the simplest and oldest open molding method for fabricating composites. At first, dry fibers in the form of woven, knitted, stitched, or bond fabrics are manually placed in the mold, and a brush is used to apply the resin matrix on the reinforcing material.

The methods of open mold fabrication:

1. Hand Lay-up.
2. Spray-up method.
3. Tape Lay-up.
4. Filament Winding.
5. Autoclave Curing.

STOCK – The blending of different additives with raw rubber is known as rubber compounding.

Rubber mixing process (RMP) is one of the determinations of physical and chemical properties of vulcanized rubber. … The order of mixing rubber chemicals and fillers can affect the physical properties such as abrasion resistance of vulcanized rubber.

Rubber compounding was performed on a two-roll mill (Lab Walzwerk MT 6″×13″, Rubicon, Germany) in a three-stage process. In the first stage, the rubber was mixed with zinc oxide, stearic acid, CB, and Struktol or IPPD. Then the rubber/MLG masterbatch was added to the rubber compound in the second stage.

STRAIN– Strain is the deformation or displacement of material that results from an applied stress. Note: A material’s change in length (L – L0) is sometimes represented as δ. The most common way to analyze the relationship between stress and strain for a particular material is with a stress-strain diagram.

Stress is defined as the force experienced by the object which causes a change in the object while a strain is defined as the change in the shape of an object when stress is applied.

Strain under a tensile stress is called tensile strain, strain under bulk stress is called bulk strain (or volume strain), and that caused by shear stress is called shear strain. stress = (elastic modulus) × strain. stress = (elastic modulus) × strain.

Stress strain curve is a behavior of material when it is subjected to load and frm SN curve we can say stress generates only when there is deformation (or it is about to deform) caused by some mechanical or physical forces. Therefore Strain always comes first then only stress generates.

STRESS– Stress is the force per unit area on a body that tends to cause it to change shape. Stress is a measure of the internal forces in a body between its particles. These internal forces are a reaction to the external forces applied on the body that cause it to separate, compress or slide.

Stress has units of force per area: N/m2 (SI) or lb/in2 (US). The SI units are commonly referred to as Pascals, abbreviated Pa.

The bending stress is computed for the rail by the equation Sb = Mc/I, where Sb is the bending stress in pounds per square inch, M is the maximum bending moment in pound-inches, I is the moment of inertia of the rail in (inches)4, and c is the distance in inches from the base of rail to its neutral axis.

STRESS RELAXATION– Stress relaxation describes how polymers relieve stress under constant strain. Because they are viscoelastic, polymers behave in a nonlinear, non-Hookean fashion. This nonlinearity is described by both stress relaxation and a phenomenon known as creep, which describes how polymers strain under constant stress.

To quantify the rate of stress relaxation, a time constant (Ï„) was defined as the time at which the elastic modulus relaxes to the halfway between the initial modulus and the equilibrium modulus at the end of stress relaxation test (Fig. S4A).

two terms are sometimes used interchangeably, although they are really different. Creep is an increase in plastic strain under constant stress. Stress relaxation is a decrease in stress under constant strain. … Creep is an increased tendency toward more strain and plastic deformation with no change in stress.

Stress relaxation is a time-dependent decrease in stress under a constant strain. This characteristic behavior of the polymer is studied by applying a fixed amount of deformation to a specimen and measuring the load required to maintain it as a function

SUBSTRATE- Substrate is a term used in materials science to describe the base material on which processing is conducted to produce new film or layers of material such as deposited coatings. A typical substrate might be a metal, onto which a coating might be deposited by any of the following processes: … Conversion coating.

Substrate refers to an underlying layer that supports the primary layer. The term is commonly used in the construction and renovation industry. Substrate material often refers to rock, soil, and other natural elements, especially when discussed in the context of foundation construction.

A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock (its substrate) can be itself a substrate for an animal that lives on top of the algae. Inert substrates are used as growing support materials in the hydroponic cultivation of plants.

A substance to which another substance is applied we call it as a substrate. … For example, rock is a substrate for fungi, a page is a substrate on which ink adheres, NaCl is a substrate for the chemical reaction.

SUN CHECKING– sunlight that either passes through a medium—a window shade or the leaves of a tree—or reflects off another surface before reaching a plant. … Indirect sunlight ranges from the bright indirect light of east-facing windows to the fainter, indirect light of north-facing windows.

In other words, direct sunlight is when the path of light from the sun to the plant is a straight line. Indirect/Filtered sunlight is the type of diffuse light that casts soft shadows, like in the photo above. It refers to any sunlight that reaches the plant but is not direct.

Bright Indirect light is when the sun’s rays don’t travel directly from the sun to your plant but, instead, bounce off something first. Plants in bright, indirect light will cast blurry, indistinct shadows. Bright indirect light is approximately 800-2000 foot candles.

Safety fuse – A train of powder enclosed in cotton, jute yarn, or waterproofing compounds, which burns at a uniform rate; used for firing a cap containing the detonation compound which in turn sets off the explosive charge.

Safety lamp – A lamp with steel wire gauze covering every opening from the inside to the outside so as to prevent the passage of flame should explosive gas be encountered.

Sampling – Cutting a representative part of an ore (or coal) deposit, which should truly represent its average value.

Sandstone – A sedimentary rock consisting of quartz sand united by some cementing material, such as iron oxide or calcium carbonate.

Sapropelic Coal – A coal derived from organic residues (finely divided plant material, spores, algae) in stagnant or standing bodies of water.

Scaling – Removal of loose rock from the roof or walls. This work is dangerous and a long bar (called a scaling bar)is often used.

Scoop – A rubber tired-, battery- or diesel-powered piece of equipment designed for cleaning runways and hauling supplies.

Scrubber – Any of several forms of chemical/physical devices that remove sulfur compounds formed during coal combustion. These devices, technically know as flue gas desulfurization systems, combine the sulfur in gaseous emissions with another chemical medium to form inert “sludge,” which must then be removed for disposal.

Seam – A stratum or bed of coal.

Secondary roof – The roof strata immediately above the coalbed, requiring support during the excavating of coal.

Section – A portion of the working area of a mine.

Sediment – Solid material, both mineral and organic, that has come to rest on the earth’s surface either above or below sea level.

Selective mining – The object of selective mining is to obtain a relatively high-grade mine product; this usually entails the use of a much more expensive stopping system and high exploration and development costs in searching for and developing the separate bunches, stringers, lenses, and bands of ore.

Self-contained breathing apparatus – A self-contained supply of oxygen used during rescue work from coal mine fires and explosions; same as SCSR (self-contained self rescuer).

Self-rescuer – A small filtering device carried by a coal miner underground, either on his belt or in his pocket, to provide him with immediate protection against carbon monoxide and smoke in case of a mine fire or explosion. It is a small canister with a mouthpiece directly attached to it. The wearer breathes through the mouth, the nose being closed by a clip. The canister contains a layer of fused calcium chloride that absorbs water vapor from the mine air. The device is used for escape purposes only because it does not sustain life in atmospheres containing deficient oxygen. The length of time a self-rescuer can be used is governed mainly by the humidity in the mine air, usually between 30 minutes and one hour.

Semi-Anthracite – Coal intermediate between anthracite and semi-bituminous coal and having a fixed carbon content of between 85 percent and 92 percent. Physical properties resemble anthracite.

Semi-Bituminous Coal – Coal that ranks between bituminous and semi-anthracite. It is harder and more brittle than bituminous coal, has a high fuel ratio and burns without smoke.

Severance – The separation of a mineral interest from other interests in the land by grant or reservation. A mineral dead or grant of the land reserving a mineral interest, by the landowner before leasing, accomplishes a severance as does his execution of a mineral lease.

Shaft – A primary vertical or non-vertical opening through mine strata used for ventilation or drainage and/or for hoisting of personnel or materials; connects the surface with underground workings.

Shaftman – A workman who patrols in a slowly moving cage in a mine shaft, and maintains the shaft by working through the cage side, or on its top, or suspended from the cage bottom.

Shaft mine – An underground mine in which the main entry or access is by means of a vertical shaft.

Shale – A rock formed by consolidation of clay, mud, or silt, having a laminated structure and composed of minerals essentially unaltered since deposition.

Shearer – A mining machine for longwall faces that uses a rotating action to “shear” the material from the face as it progresses along the face.

Shift – The number of hours or the part of any day worked.

Shortwall – An underground mining method in which small areas are worked (15 to 150 feet) by a continuous miner in conjunction with the use of hydraulic roof supports.

Shuttle car – A self-discharging truck, generally with rubber tires or caterpillar-type treads, used for receiving coal from the loading or mining machine and transferring it to an underground loading point, mine railway or belt conveyor system.

Shot – The explosive charge in the coal face.

Shooting – Blasting in a mine.

Shotfirer – The official prior to detonating an explosive charge to blast coal, examines the area for gas, examines the preparations made for the blasting and when assured that all safety regulations have been complied with, detonates the shot.

Sinking – A passage driven on an incline down to coal workings in lower depths, comparable to an inside slope.

Skid – A track-mounted vehicle used to hold trips or cars from running out of control. Also it is a flat-bottom personnel or equipment carrier used in low coal.

Skip – A car being hoisted from a slope or shaft.

Slack – Small coal; the finest-sized soft coal, usually less than one inch in diameter.

Slag – The waste product of the process of smelting.

Slate – A miner’s term for any shale or slate accompanying coal. Geologically, it is a dense, fine-textured, metamorphic rock, which has excellent parallel cleavage so that it breaks into thin plates or pencil-like shapes.

Slate bar – The proper long-handled tool used to pry down loose and hazardous material from roof, face, and ribs.

Slickenside – A smooth, striated, polished surface produced on rock by friction.

Slip – A fault. A smooth joint or crack where the strata have moved on each other.

Slope – An entrance to a mine driven down through an inclined coal seam. An inside slope in a mine is a passage in the mine driven from one system of workings down through a seam, to bring up coal from a lower system of workings.

Slopeman – A workman who patrols and keeps in repair the mine’s main and back slopes.

Slope mine – An underground mine with an opening that slopes upward or downward to the coal seam.

Sloughing – The slow crumbling and falling away of material from roof, rib, and face.

Solid – Mineral that has not been undermined, sheared out, or otherwise prepared for blasting.

Sounding – Knocking on a roof to see whether it is sound and safe to work under.

Spad – A spad is a flat spike hammered into a wooden plug anchored in a hole drilled into the mine ceiling from which is threaded a plumbline. The spad is an underground survey station similar to the use of stakes in marking survey points on the surface. A pointer spad, or sight spad, is a station that allows a mine foreman to visually align entries or breaks from the main spad.

Span – The horizontal distance between the side supports or solid abutments along sides of a roadway.

Specific gravity – The weight of a substance compared with the weight of an equal volume of pure water at 4 degrees Celsius.

Splint – A hard variety of bituminous coal that ignites with difficulty, owing to its slatey structure, but makes a clear hot fire.

Split – Any division or branch of the ventilating current. Also, the workings ventilated by one branch. Also, to divide a pillar by driving one or more roads through it.

Spores – Parts of the reproductive organs of many plants that formed coal.

Stableman – A workman who cares for the horses and maintains the stable underground. In off-working days the stableman is responsible for watering the horses.

Squeeze – The settling, without breaking, of the roof and the gradual upheaval of the floor of a mine due to the weight of the overlying strata.

Steeply inclined – Said of deposits and coal seams with a dip of from 0.7 to 1 rad (40 degrees to 60 degrees).

Stemming – The noncombustible material used on top or in front of a charge or explosive.

Stripping – Mining coal by first removing the covering strata down to the coal bed; open workings as in a quarry; sometimes used to describe a final mining operation drawing pillars. When all coal is removed the roof crashes down.

Store Keeper – A semi-clerical worker who supervises a storeroom of colliery tools and equipment, and who issues these items for use upon instruction of competent authority.

Strike – The direction of the line of intersection of a bed or vein with the horizontal plane. The strike of a bed is the direction of a straight line that connects two points of equal elevation on the bed.

Stripping – Mining coal by first removing the covering strata down to the coal bed; open workings as in a quarry; sometimes used to describe a final mining operation drawing pillars. When all coal is removed the roof crashes down.

Stripping ratio – The unit amount of overburden that must be removed to gain access to a similar unit amount of coal or mineral material.

Stump – Any small pillar.

Subbituminous – Coal of a rank intermediate between lignite and bituminous.

Sub-Bituminous Coal – A black coal that ranks between lignite and bituminous coals. It has higher carbon and lower moisture content than lignite.

Sub-Bituminous “A” Coal – A non-binding sub-bituminous coal having between 11,000 and 13,000 B.T.U.

Sub-Bituminous “B” Coal – A non-binding sub-bituminous coal having between 9,500 and 11,000 B.T.U.

Sub-Bituminous “C” Coal – A non-binding sub-bituminous coal having between 8,300 and 9,500 B.T.U.

Subsidence – The gradual sinking, or sometimes abrupt collapse, of the rock and soil layers into an underground mine. Structures and surface features above the subsidence area can be affected.

Sump – The bottom of a shaft, or any other place in a mine, that is used as a collecting point for drainage water.

Sumping – To force the cutter bar of a machine into or under the coal. Also called a sumping cut, or sumping in.

Support – The all-important function of keeping the mine workings open. As a verb, it refers to this function; as a noun it refers to all the equipment and materials–timber, roof bolts, concrete, steel, etc.–that are used to carry out this function.

Surface mine – A mine in which the coal lies near the surface and can be extracted by removing the covering layers of rock and soil.

Suspension – Weaker strata hanging from stronger, overlying strata by means of roof bolts.

Sulphur – Coal constituent usually in the form of pyrite.

Sump – A basin or collection place in a mine, into which water runs to be pumped out.

Syncline – A fold in rock in which the strata dip inward from both sides toward the axis. The opposite of anticline.