Misplaced Pages

#517482

71-470: Tankers offload at LOOP by pumping crude oil through hoses connected to a Single Buoy Mooring (SBM) base. Three SPMs are located 8,000 feet (2.4 km) from the Marine Terminal. The SPMs are designed to handle ships up to 700,000 deadweight tons (635,000 metric tonnes ). The crude oil then moves to the Marine Terminal via a 56-inch (1.4 m) diameter submarine pipeline . The Marine Terminal consists of

142-700: A ρ w 1 − ρ a ρ w = R D V − ρ a ρ w 1 − ρ a ρ w . {\displaystyle RD_{\mathrm {A} }={{\rho _{\mathrm {s} } \over \rho _{\mathrm {w} }}-{\rho _{\mathrm {a} } \over \rho _{\mathrm {w} }} \over 1-{\rho _{\mathrm {a} } \over \rho _{\mathrm {w} }}}={RD_{\mathrm {V} }-{\rho _{\mathrm {a} } \over \rho _{\mathrm {w} }} \over 1-{\rho _{\mathrm {a} } \over \rho _{\mathrm {w} }}}.} In

213-465: A ) . {\displaystyle F_{\mathrm {w} }=g\left(m_{\mathrm {b} }-\rho _{\mathrm {a} }{\frac {m_{\mathrm {b} }}{\rho _{\mathrm {b} }}}+V\rho _{\mathrm {w} }-V\rho _{\mathrm {a} }\right).} If we subtract the force measured on the empty bottle from this (or tare the balance before making the water measurement) we obtain. F w , n = g V ( ρ w − ρ

284-445: A ) = ρ s − ρ a ρ w − ρ a . {\displaystyle SG_{\mathrm {A} }={\frac {gV(\rho _{\mathrm {s} }-\rho _{\mathrm {a} })}{gV(\rho _{\mathrm {w} }-\rho _{\mathrm {a} })}}={\frac {\rho _{\mathrm {s} }-\rho _{\mathrm {a} }}{\rho _{\mathrm {w} }-\rho _{\mathrm {a} }}}.} This

355-418: A ) , {\displaystyle F_{\mathrm {s,n} }=gV(\rho _{\mathrm {s} }-\rho _{\mathrm {a} }),} where ρ s is the density of the sample. The ratio of the sample and water forces is: S G A = g V ( ρ s − ρ a ) g V ( ρ w − ρ

426-439: A ) , {\displaystyle F_{\mathrm {w,n} }=gV(\rho _{\mathrm {w} }-\rho _{\mathrm {a} }),} where the subscript n indicated that this force is net of the force of the empty bottle. The bottle is now emptied, thoroughly dried and refilled with the sample. The force, net of the empty bottle, is now: F s , n = g V ( ρ s − ρ

497-405: A m p l e {\displaystyle \rho _{\mathrm {sample} }} is the density of the sample and ρ H 2 O {\displaystyle \rho _{\mathrm {H_{2}O} }} is the density of water. The apparent specific gravity is simply the ratio of the weights of equal volumes of sample and water in air: S G a p p

568-670: A m p l e V m H 2 O V = m s a m p l e m H 2 O g g = W V , sample W V , H 2 O , {\displaystyle SG_{\mathrm {true} }={\frac {\rho _{\mathrm {sample} }}{\rho _{\mathrm {H_{2}O} }}}={\frac {\frac {m_{\mathrm {sample} }}{V}}{\frac {m_{\mathrm {H_{2}O} }}{V}}}={\frac {m_{\mathrm {sample} }}{m_{\mathrm {H_{2}O} }}}{\frac {g}{g}}={\frac {W_{\mathrm {V} ,{\text{sample}}}}{W_{\mathrm {V} ,\mathrm {H_{2}O} }}},} where g

639-405: A r e n t = W A , sample W A , H 2 O , {\displaystyle SG_{\mathrm {apparent} }={\frac {W_{\mathrm {A} ,{\text{sample}}}}{W_{\mathrm {A} ,\mathrm {H_{2}O} }}},} where W A , sample {\displaystyle W_{A,{\text{sample}}}} represents the weight of

710-464: A 25-million-barrels (4,000,000 m) Brine Storage Reservoir. The brine reservoir is supersaturated with salts so as to prevent further degradation of the massive salt dome in which the eight caverns store the crude. This is because the supersaturated brine is much more dense than the crude oil , and as it is pumped into the caverns to push the crude to the surface and into the surface distribution systems. This results in virtually no loss of quality to

781-567: A 48-inch (1.2 m) diameter pipeline. The distance to shore puts LOOP outside U.S. territorial waters , and special agreements in international sea law are made to allow ships from other countries to come under U.S. jurisdiction to visit LOOP. LOOP's onshore facilities, Fourchon Booster Station and Clovelly Dome Storage Terminal, are located just on-shore in Fourchon and 25 miles (40.2 km) inland near Galliano, Louisiana . The Fourchon Booster Station has four 6,000-hp (4.5 MW) pumps which increase

SECTION 10

#1732855841518

852-430: A control platform and a pumping platform. The control platform is equipped with a helicopter pad, living quarters, control room, vessel traffic control station, offices and life support equipment. The pumping platform contains four 7,000- hp (5 MW ) pumps , power generators , metering and laboratory facilities. Crude oil is only handled on the pumping platform where it is measured, sampled, and boosted to shore via

923-411: A liquid can be measured using a hydrometer. This consists of a bulb attached to a stalk of constant cross-sectional area, as shown in the adjacent diagram. First the hydrometer is floated in the reference liquid (shown in light blue), and the displacement (the level of the liquid on the stalk) is marked (blue line). The reference could be any liquid, but in practice it is usually water. The hydrometer

994-412: A molar volume of 22.259 L under those same conditions. Those with SG greater than 1 are denser than water and will, disregarding surface tension effects, sink in it. Those with an SG less than 1 are less dense than water and will float on it. In scientific work, the relationship of mass to volume is usually expressed directly in terms of the density (mass per unit volume) of the substance under study. It

1065-462: A specific, but not necessarily accurately known volume, V and is placed upon a balance, it will exert a force F b = g ( m b − ρ a m b ρ b ) , {\displaystyle F_{\mathrm {b} }=g\left(m_{\mathrm {b} }-\rho _{\mathrm {a} }{\frac {m_{\mathrm {b} }}{\rho _{\mathrm {b} }}}\right),} where m b

1136-429: Is a dimensionless quantity , as it is the ratio of either densities or weights R D = ρ s u b s t a n c e ρ r e f e r e n c e , {\displaystyle {\mathit {RD}}={\frac {\rho _{\mathrm {substance} }}{\rho _{\mathrm {reference} }}},} where R D {\displaystyle RD}

1207-409: Is a device used to determine the density of a liquid. A pycnometer is usually made of glass , with a close-fitting ground glass stopper with a capillary tube through it, so that air bubbles may escape from the apparatus. This device enables a liquid's density to be measured accurately by reference to an appropriate working fluid, such as water or mercury , using an analytical balance . If

1278-488: Is air at room temperature (20 °C or 68 °F). The term "relative density" (abbreviated r.d. or RD ) is preferred in SI , whereas the term "specific gravity" is gradually being abandoned. If a substance's relative density is less than 1 then it is less dense than the reference; if greater than 1 then it is denser than the reference. If the relative density is exactly 1 then the densities are equal; that is, equal volumes of

1349-420: Is being measured. For true ( in vacuo ) relative density calculations air pressure must be considered (see below). Temperatures are specified by the notation ( T s / T r ) with T s representing the temperature at which the sample's density was determined and T r the temperature at which the reference (water) density is specified. For example, SG (20 °C/4 °C) would be understood to mean that

1420-422: Is being measured. For true ( in vacuo ) specific gravity calculations, air pressure must be considered (see below). Temperatures are specified by the notation ( T s / T r ), with T s representing the temperature at which the sample's density was determined and T r the temperature at which the reference (water) density is specified. For example, SG (20 °C/4 °C) would be understood to mean that

1491-408: Is called the apparent relative density , denoted by subscript A, because it is what we would obtain if we took the ratio of net weighings in air from an analytical balance or used a hydrometer (the stem displaces air). Note that the result does not depend on the calibration of the balance. The only requirement on it is that it read linearly with force. Nor does RD A depend on the actual volume of

SECTION 20

#1732855841518

1562-422: Is easy to measure, the volume of an irregularly shaped sample can be more difficult to ascertain. One method is to put the sample in a water-filled graduated cylinder and read off how much water it displaces. Alternatively the container can be filled to the brim, the sample immersed, and the volume of overflow measured. The surface tension of the water may keep a significant amount of water from overflowing, which

1633-786: Is especially problematic for small samples. For this reason it is desirable to use a water container with as small a mouth as possible. For each substance, the density, ρ , is given by ρ = Mass Volume = Deflection × Spring Constant Gravity Displacement W a t e r L i n e × Area C y l i n d e r . {\displaystyle \rho ={\frac {\text{Mass}}{\text{Volume}}}={\frac {{\text{Deflection}}\times {\frac {\text{Spring Constant}}{\text{Gravity}}}}{{\text{Displacement}}_{\mathrm {WaterLine} }\times {\text{Area}}_{\mathrm {Cylinder} }}}.} When these densities are divided, references to

1704-469: Is extremely important that the analyst enter the table with the correct form of relative density. For example, in the brewing industry, the Plato table , which lists sucrose concentration by mass against true RD, were originally (20 °C/4 °C) that is based on measurements of the density of sucrose solutions made at laboratory temperature (20 °C) but referenced to the density of water at 4 °C which

1775-417: Is extremely important that the analyst enter the table with the correct form of specific gravity. For example, in the brewing industry, the Plato table lists sucrose concentration by weight against true SG, and was originally (20 °C/4 °C) i.e. based on measurements of the density of sucrose solutions made at laboratory temperature (20 °C) but referenced to the density of water at 4 °C which

1846-501: Is filled with air but as that air displaces an equal amount of air the weight of that air is canceled by the weight of the air displaced. Now we fill the bottle with the reference fluid e.g. pure water. The force exerted on the pan of the balance becomes: F w = g ( m b − ρ a m b ρ b + V ρ w − V ρ

1917-487: Is in industry where specific gravity finds wide application, often for historical reasons. True specific gravity of a liquid can be expressed mathematically as: S G t r u e = ρ s a m p l e ρ H 2 O , {\displaystyle SG_{\mathrm {true} }={\frac {\rho _{\mathrm {sample} }}{\rho _{\mathrm {H_{2}O} }}},} where ρ s

1988-607: Is more easily and perhaps more accurately measured without measuring volume. Using a spring scale, the sample is weighed first in air and then in water. Relative density (with respect to water) can then be calculated using the following formula: R D = W a i r W a i r − W w a t e r , {\displaystyle RD={\frac {W_{\mathrm {air} }}{W_{\mathrm {air} }-W_{\mathrm {water} }}},} where This technique cannot easily be used to measure relative densities less than one, because

2059-672: Is nearly always 1 atm (101.325 kPa ). Where it is not, it is more usual to specify the density directly. Temperatures for both sample and reference vary from industry to industry. In British brewing practice, the specific gravity, as specified above, is multiplied by 1000. Specific gravity is commonly used in industry as a simple means of obtaining information about the concentration of solutions of various materials such as brines , must weight ( syrups , juices, honeys, brewers wort , must , etc.) and acids. Relative density ( R D {\displaystyle RD} ) or specific gravity ( S G {\displaystyle SG} )

2130-515: Is necessary to specify the temperatures and pressures at which the densities or masses were determined. It is nearly always the case that measurements are made at nominally 1 atmosphere (101.325 kPa ignoring the variations caused by changing weather patterns) but as relative density usually refers to highly incompressible aqueous solutions or other incompressible substances (such as petroleum products) variations in density caused by pressure are usually neglected at least where apparent relative density

2201-437: Is normally assumed to be water at 4 ° C (or, more precisely, 3.98 °C, which is the temperature at which water reaches its maximum density). In SI units, the density of water is (approximately) 1000  kg / m or 1  g / cm , which makes relative density calculations particularly convenient: the density of the object only needs to be divided by 1000 or 1, depending on the units. The relative density of gases

Louisiana Offshore Oil Port - Misplaced Pages Continue

2272-623: Is often measured with respect to dry air at a temperature of 20 °C and a pressure of 101.325 kPa absolute, which has a density of 1.205 kg/m . Relative density with respect to air can be obtained by R D = ρ g a s ρ a i r ≈ M g a s M a i r , {\displaystyle {\mathit {RD}}={\frac {\rho _{\mathrm {gas} }}{\rho _{\mathrm {air} }}}\approx {\frac {M_{\mathrm {gas} }}{M_{\mathrm {air} }}},} where M {\displaystyle M}

2343-421: Is often used to specify a ship's maximum permissible deadweight (i.e. when it is fully loaded so that its Plimsoll line is at water level), although it may also denote the actual DWT of a ship not loaded to capacity. Deadweight tonnage is a measure of a vessel's weight carrying capacity, not including the empty weight of the ship. It is distinct from the displacement (weight of water displaced), which includes

2414-455: Is relative density, ρ s u b s t a n c e {\displaystyle \rho _{\mathrm {substance} }} is the density of the substance being measured, and ρ r e f e r e n c e {\displaystyle \rho _{\mathrm {reference} }} is the density of the reference. (By convention ρ {\displaystyle \rho } ,

2485-499: Is taken from this work which uses SG (17.5 °C/17.5 °C). As a final example, the British RD units are based on reference and sample temperatures of 60 °F and are thus (15.56 °C/15.56 °C). Relative density can be calculated directly by measuring the density of a sample and dividing it by the (known) density of the reference substance. The density of the sample is simply its mass divided by its volume. Although mass

2556-403: Is the molar mass and the approximately equal sign is used because equality pertains only if 1 mol of the gas and 1 mol of air occupy the same volume at a given temperature and pressure, i.e., they are both ideal gases . Ideal behaviour is usually only seen at very low pressure. For example, one mol of an ideal gas occupies 22.414 L at 0 °C and 1 atmosphere whereas carbon dioxide has

2627-511: Is the local acceleration due to gravity, V is the volume of the sample and of water (the same for both), ρ sample is the density of the sample, ρ H 2 O is the density of water, W V represents a weight obtained in vacuum, m s a m p l e {\displaystyle {\mathit {m}}_{\mathrm {sample} }} is the mass of the sample and m H 2 O {\displaystyle {\mathit {m}}_{\mathrm {H_{2}O} }}

2698-606: Is the mass of an equal volume of water. The density of water and of the sample varies with temperature and pressure, so it is necessary to specify the temperatures and pressures at which the densities or weights were determined. Measurements are nearly always made at 1 nominal atmosphere (101.325 kPa ± variations from changing weather patterns), but as specific gravity usually refers to highly incompressible aqueous solutions or other incompressible substances (such as petroleum products), variations in density caused by pressure are usually neglected at least where apparent specific gravity

2769-422: Is the mass of the bottle and g the gravitational acceleration at the location at which the measurements are being made. ρ a is the density of the air at the ambient pressure and ρ b is the density of the material of which the bottle is made (usually glass) so that the second term is the mass of air displaced by the glass of the bottle whose weight, by Archimedes Principle must be subtracted. The bottle

2840-412: Is then filled with a liquid of known density, in which the powder is completely insoluble. The weight of the displaced liquid can then be determined, and hence the relative density of the powder. A gas pycnometer , the gas-based manifestation of a pycnometer, compares the change in pressure caused by a measured change in a closed volume containing a reference (usually a steel sphere of known volume) with

2911-432: Is then floated in a liquid of unknown density (shown in green). The change in displacement, Δ x , is noted. In the example depicted, the hydrometer has dropped slightly in the green liquid; hence its density is lower than that of the reference liquid. It is necessary that the hydrometer floats in both liquids. The application of simple physical principles allows the relative density of the unknown liquid to be calculated from

Louisiana Offshore Oil Port - Misplaced Pages Continue

2982-595: Is very close to the temperature at which water has its maximum density of ρ ( H 2 O ) equal to 0.999972 g/cm (or 62.43 lb·ft ). The ASBC table in use today in North America, while it is derived from the original Plato table is for apparent relative density measurements at (20 °C/20 °C) on the IPTS-68 scale where the density of water is 0.9982071 g/cm . In the sugar, soft drink, honey, fruit juice and related industries sucrose concentration by mass

3053-567: Is very close to the temperature at which water has its maximum density, ρ H 2 O equal to 999.972 kg/m in SI units ( 0.999 972  g/cm in cgs units or 62.43 lb/cu ft in United States customary units ). The ASBC table in use today in North America for apparent specific gravity measurements at (20 °C/20 °C) is derived from the original Plato table using Plato et al.‘s value for SG(20 °C/4 °C) = 0.998 2343 . In

3124-491: The Archimedes buoyancy principle, the buoyancy force acting on the hydrometer is equal to the weight of liquid displaced. This weight is equal to the mass of liquid displaced multiplied by g , which in the case of the reference liquid is ρ ref Vg . Setting these equal, we have m g = ρ r e f V g {\displaystyle mg=\rho _{\mathrm {ref} }Vg} or just Exactly

3195-539: The International Convention for the Prevention of Pollution From Ships , deadweight is explicitly defined as the difference in tonnes between the displacement of a ship in water of a specific gravity of 1.025 (corresponding to average density of sea water of 1,025 kg/m or 1,728 lb/cu yd) at the draft corresponding to the assigned summer freeboard and the light displacement (lightweight) of

3266-461: The mineral content of a rock or other sample. Gemologists use it as an aid in the identification of gemstones . Water is preferred as the reference because measurements are then easy to carry out in the field (see below for examples of measurement methods). As the principal use of relative density measurements in industry is determination of the concentrations of substances in aqueous solutions and these are found in tables of RD vs concentration it

3337-474: The Greek letter rho , denotes density.) The reference material can be indicated using subscripts: R D s u b s t a n c e / r e f e r e n c e {\displaystyle RD_{\mathrm {substance/reference} }} which means "the relative density of substance with respect to reference ". If the reference is not explicitly stated then it

3408-508: The above formula: ρ s u b s t a n c e = S G × ρ H 2 O . {\displaystyle \rho _{\mathrm {substance} }=SG\times \rho _{\mathrm {H_{2}O} }.} Occasionally a reference substance other than water is specified (for example, air), in which case specific gravity means density relative to that reference. The density of substances varies with temperature and pressure so that it

3479-405: The change in displacement. (In practice the stalk of the hydrometer is pre-marked with graduations to facilitate this measurement.) In the explanation that follows, Since the floating hydrometer is in static equilibrium , the downward gravitational force acting upon it must exactly balance the upward buoyancy force. The gravitational force acting on the hydrometer is simply its weight, mg . From

3550-411: The change in pressure caused by the sample under the same conditions. The difference in change of pressure represents the volume of the sample as compared to the reference sphere, and is usually used for solid particulates that may dissolve in the liquid medium of the pycnometer design described above, or for porous materials into which the liquid would not fully penetrate. When a pycnometer is filled to

3621-474: The crude oil offload. 28°53′07″N 90°01′30″W  /  28.8852°N 90.02508°W  / 28.8852; -90.02508 Deadweight tonnage Deadweight tonnage (also known as deadweight ; abbreviated to DWT , D.W.T. , d.w.t. , or dwt ) or tons deadweight (DWT) is a measure of how much weight a ship can carry. It is the sum of the weights of cargo , fuel, fresh water , ballast water , provisions, passengers, and crew . DWT

SECTION 50

#1732855841518

3692-487: The densities used here and in the rest of this article are based on that scale. On the previous IPTS-68 scale, the densities at 20 °C and 4 °C are 0.998 2041 and 0.999 9720 respectively, resulting in an SG (20 °C/4 °C) value for water of 0.998 232 . As the principal use of specific gravity measurements in industry is determination of the concentrations of substances in aqueous solutions and as these are found in tables of SG versus concentration, it

3763-406: The densities used here and in the rest of this article are based on that scale. On the previous IPTS-68 scale the densities at 20 °C and 4 °C are, respectively, 0.9982041 and 0.9999720 resulting in an RD (20 °C/4 °C) value for water of 0.99823205. The temperatures of the two materials may be explicitly stated in the density symbols; for example: where the superscript indicates

3834-410: The density of dry air at 101.325 kPa at 20 °C is 0.001205 g/cm and that of water is 0.998203 g/cm we see that the difference between true and apparent relative densities for a substance with relative density (20 °C/20 °C) of about 1.100 would be 0.000120. Where the relative density of the sample is close to that of water (for example dilute ethanol solutions) the correction

3905-407: The density of the sample was determined at 20 °C and of the water at 4 °C. Taking into account different sample and reference temperatures, while SG H 2 O = 1.000 000 (20 °C/20 °C), it is also the case that SG H 2 O = 0.998 2008 ⁄ 0.999 9720 = 0.998 2288 (20 °C/4 °C). Here, temperature is being specified using the current ITS-90 scale and

3976-399: The density of the sample was determined at 20 °C and of the water at 4 °C. Taking into account different sample and reference temperatures, while SG H 2 O = 1.000000 (20 °C/20 °C) it is also the case that RD H 2 O = ⁠ 0.9982008 / 0.9999720 ⁠ = 0.9982288 (20 °C/4 °C). Here temperature is being specified using the current ITS-90 scale and

4047-412: The flask is weighed empty, full of water, and full of a liquid whose relative density is desired, the relative density of the liquid can easily be calculated. The particle density of a powder, to which the usual method of weighing cannot be applied, can also be determined with a pycnometer. The powder is added to the pycnometer, which is then weighed, giving the weight of the powder sample. The pycnometer

4118-497: The pressure and crude oil flow en route to the Clovelly Dome Storage Terminal. The Clovelly Dome Storage Terminal is used to store crude oil in underground salt domes before it is shipped to the various refineries. The terminal consists of eight caverns with a total capacity of 50 million barrels (7,900,000 m), a pump station with four 6,000-hp pumps, meters to measure the crude oil receipts and deliveries, and

4189-438: The pycnometer. Further manipulation and finally substitution of RD V , the true relative density (the subscript V is used because this is often referred to as the relative density in vacuo ), for ρ s / ρ w gives the relationship between apparent and true relative density: R D A = ρ s ρ w − ρ

4260-766: The reference liquid, and the known properties of the hydrometer. If Δ x is small then, as a first-order approximation of the geometric series equation ( 4 ) can be written as: R D n e w / r e f ≈ 1 + A Δ x m ρ r e f . {\displaystyle RD_{\mathrm {new/ref} }\approx 1+{\frac {A\Delta x}{m}}\rho _{\mathrm {ref} }.} This shows that, for small Δ x , changes in displacement are approximately proportional to changes in relative density. A pycnometer (from Ancient Greek : πυκνός , romanized :  puknos , lit.   'dense'), also called pyknometer or specific gravity bottle ,

4331-417: The same equation applies when the hydrometer is floating in the liquid being measured, except that the new volume is V − A Δ x (see note above about the sign of Δ x ). Thus, Combining ( 1 ) and ( 2 ) yields But from ( 1 ) we have V = m / ρ ref . Substituting into ( 3 ) gives This equation allows the relative density to be calculated from the change in displacement, the known density of

SECTION 60

#1732855841518

4402-500: The sample measured in air and W A , H 2 O {\displaystyle {W_{\mathrm {A} ,\mathrm {H_{2}O} }}} the weight of an equal volume of water measured in air. It can be shown that true specific gravity can be computed from different properties: S G t r u e = ρ s a m p l e ρ H 2 O = m s

4473-405: The sample will then float. W water becomes a negative quantity, representing the force needed to keep the sample underwater. Another practical method uses three measurements. The sample is weighed dry. Then a container filled to the brim with water is weighed, and weighed again with the sample immersed, after the displaced water has overflowed and been removed. Subtracting the last reading from

4544-465: The ship's own weight, or the volumetric measures of gross tonnage or net tonnage (and the legacy measures gross register tonnage and net register tonnage ). Deadweight tonnage was historically expressed in long tons , but is now usually given internationally in tonnes (metric tons). In modern international shipping conventions such as the International Convention for the Safety of Life at Sea and

4615-410: The ship. Specific gravity Relative density , also called specific gravity , is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nearly always measured with respect to water at its densest (at 4 °C or 39.2 °F); for gases, the reference

4686-1256: The spring constant, gravity and cross-sectional area simply cancel, leaving R D = ρ o b j e c t ρ r e f = Deflection O b j . Displacement O b j . Deflection R e f . Displacement R e f . = 3   i n 20   m m 5   i n 34   m m = 3   i n × 34   m m 5   i n × 20   m m = 1.02. {\displaystyle RD={\frac {\rho _{\mathrm {object} }}{\rho _{\mathrm {ref} }}}={\frac {\frac {{\text{Deflection}}_{\mathrm {Obj.} }}{{\text{Displacement}}_{\mathrm {Obj.} }}}{\frac {{\text{Deflection}}_{\mathrm {Ref.} }}{{\text{Displacement}}_{\mathrm {Ref.} }}}}={\frac {\frac {3\ \mathrm {in} }{20\ \mathrm {mm} }}{\frac {5\ \mathrm {in} }{34\ \mathrm {mm} }}}={\frac {3\ \mathrm {in} \times 34\ \mathrm {mm} }{5\ \mathrm {in} \times 20\ \mathrm {mm} }}=1.02.} Relative density

4757-481: The sugar, soft drink, honey, fruit juice and related industries, sucrose concentration by weight is taken from a table prepared by A. Brix , which uses SG (17.5 °C/17.5 °C). As a final example, the British SG units are based on reference and sample temperatures of 60 °F and are thus (15.56 °C/15.56 °C). Given the specific gravity of a substance, its actual density can be calculated by rearranging

4828-418: The sum of the first two readings gives the weight of the displaced water. The relative density result is the dry sample weight divided by that of the displaced water. This method allows the use of scales which cannot handle a suspended sample. A sample less dense than water can also be handled, but it has to be held down, and the error introduced by the fixing material must be considered. The relative density of

4899-426: The temperature at which the density of the material is measured, and the subscript indicates the temperature of the reference substance to which it is compared. Relative density can also help to quantify the buoyancy of a substance in a fluid or gas, or determine the density of an unknown substance from the known density of another. Relative density is often used by geologists and mineralogists to help determine

4970-403: The two substances have the same mass. If the reference material is water, then a substance with a relative density (or specific gravity) less than 1 will float in water. For example, an ice cube, with a relative density of about 0.91, will float. A substance with a relative density greater than 1 will sink. Temperature and pressure must be specified for both the sample and the reference. Pressure

5041-453: The usual case we will have measured weights and want the true relative density. This is found from R D V = R D A − ρ a ρ w ( R D A − 1 ) . {\displaystyle RD_{\mathrm {V} }=RD_{\mathrm {A} }-{\rho _{\mathrm {a} } \over \rho _{\mathrm {w} }}(RD_{\mathrm {A} }-1).} Since

#517482