nyuuzyou/wikis huggingface dataset:
Lanthanum

== Description ==
A soft, silvery-white metallic rare-earth element. Lanthanum is a malleable metal that occurs naturally in the minerals monazite and bastnasite. First identified by Mosander in 1839, it ranks 57th in abundance of elements in the earth's crust. Lanthanum oxidizes in air with the corroded layers spalling off to expose new surfaces. The trivalent element is very reactive and forms alloys and salts readily. Lanthanum is used in electronic devices, and for rocket propellants, and x-ray screen phosphors.
== Synonyms and Related Terms ==
La
== Risks ==
* Spontaneous ignition of powder. 
* Ingestion may cause liver damage and delay blood clotting.
==Physical and Chemical Properties==
Soluble in acids. Slowly decomposes in water to form lanthanum hydroxide and hydrogen.
Composition 	La (atomic no. 57)
CAS 	7439-91-0
Melting Point 	920 C
Density 	6.19 g/ml
Molecular Weight	at. wt. = 138.9055
Boiling Point 	3464 C
==Resources and Citations==
* Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
* Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
* The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 5374
Category:Materials database
Lap

== Description ==
1) The line or region produced when one layer of paint or varnish overlaps another recently applied stroke. When the two strokes are applied wet-on-wet, the lap area should merge and disappear.
2) An abrasive wheel or disk used for the rotary polishing of metals, gems or cross sections.
3) A cylinder or rod containing a continuous rolled mat of cotton, flax or wool fibers that have been carded and are waiting further processing.
==Resources and Citations==
* Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
* The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
* ASTM, "Standard Terminology Relating to Paint, Varnish, Lacquer and Related Products", Annual Book of ASTM Standards, Section 6, Paints, Related Coatings and Aromatics, ASTM, D16, 7-Jan, Jul-96
Category:Materials database
Lapilli

== Description ==
A size classification for small pyroclastic fragments of lava. Lapilli means "little stones" in Latin. Formed by droplets of molten lava, cooled in the air, the stones range in size from 2 to 64 mm. Lapilli occur in spheroid, teardrop, dumbbell, or button-like shapes.
== Synonyms and Related Terms ==
lapillus (singular); lapilli (Port.)
==Resources and Citations==
* José Delgado Rodrigues, LNEC, Contributed information, 2009
* Wikipedia: Lapilli (accessed March 2010)
Category:Materials database
Lapis infernis

== Description ==
An archaic name for fused silver nitrate. The caustic metal salt was used for cauterizing wounds, silvering mirrors and for silver plating.
==Resources and Citations==
* Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985
Category:Materials database
Lapis solis

== Description ==
Common name for barium sulfide used prior to the 1800s when chemical compound names were standardized (Schur 1985). The gray or green material was also called Bolognian phosphorus and sulphuret of barium.
== Synonyms and Related Terms ==
barium sulfide; Bolognian phosphorus; sulphuret of barium
==Resources and Citations==
* Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985
Category:Materials database
Laponite RD

== Description ==
[Laporte Absorbents] A brand name for a synthetically prepared clay composed of sodium magnesium lithium silicate. When mixed with water, Laponite forms a clear thixotropic gel. Industrially, it is used in paints, inks, cleaning materials, shampoos and cosmetics. In some conservation treatments, Laponite has been used as a poulticing material to remove stains and dirt from ceramic and stone objects.
== Risks ==
* Dust may contain fine particle silica.
==Physical and Chemical Properties==
Disperses and gels in water.
==Resources and Citations==
* D.Ling, "Laponite Poulticing", Conservation News, 46, p.10-11,1991.
* Ceramics and Glass Conservation Section, List of Workshop Materials, The British Museum, London
* Marie Svoboda, Conservation Survey Index, unpublished, 1997
* Gordon Hanlon, contributed information, 1998
Category:Materials database
Lappet weave

== Description ==
A fabric with added dots or figures periodically incorporated in a plain weave. Lappet weave fabrics are made using a lappet frame. The additional spots are made with an extra warp thread. Dotted swiss is an example of a lappet weave fabric.
== Synonyms and Related Terms ==
dotted swiss; een weefsel met flap, slip (Ned);
Category:Materials database
Larch

== Description ==
Any of several deciduous conifer trees of the genus Larix, most often found in the mountainous regions of southern and central Europe, North America and parts of Asia. The straight, tall, larch trees have short, needle-like leaves that turn yellow and drop in the fall. Larch wood is moderately heavy, durable and has a fine, uniform texture with a straight grain. While the wood is occasionally used for furniture, flooring, and cabinetry, it is more often used for telephone poles, posts, and railroad ties. The resin sap from larch trees is sold as Venice turpentine and larch balsam. 
See also eastern tamarack, and western larch.
== Synonyms and Related Terms ==
Larix; tamarack; hackmatack; Modřín (Ces.); Lærk (Dan.); Lärchen (Deut.); mélèze (Fr.); larici (It.); lariks (Ned.); modrzew (Pol.); larix (Port.); Lärkträd (Sven.); alerce (Esp.); laricio (Port.)
== Physical and Chemical Properties ==
Heartwood is reddish brown. Annuals rings are distinct. Density = 30-40 ppcf
Paper fiber type: Softwood. Using transmitted light microscopy, fibers are identified by the presence of many piceoid pits (3-4+ across). Since this is an abrupt transition softwood, a distinct difference between early and late wood fibers can be seen. Appearance with Graff "C" stain: pale pink, varies with pulping and bleaching. Average dimensions of fibers: length 5mm, width 40-50μm. Common pulping method: kraft and sulfite.
== Additional Images ==
File:larchwg.jpg|Larch (Larix spp.)
File:Larch 10x.jpg|Larch paper pulp stained with Graffs "C" Stain
File:Larch 40x piceiod pits.jpg|Larch paper pulp stained with Graffs "C" Stain
== Resources and Citations ==
* Schoch, W., Heller, I., Schweingruber, F.H., Kienast, F., 2004:Wood anatomy of central European Species: European Larch,Larix decidua Mill.
* R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966
* F. H. Titmuss, Commercial Timbers of the World, The Technical Press Ltd., London, 1965 Comment: 30-40 ppcf
* Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996
* Encyclopedia Britannica, http://www.britannica.com Comment: "larch" [Accessed October 18, 2001].
* Wikipedia: Larch (Accessed Feb. 25, 2006 and October 2024)
* Western Pine Association, Portland, Oregon: air-dry weight = 36 pcf
* Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
* Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
* The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
* CRC Handbook of Chemistry and Physics, Robert Weast (ed.), CRC Press, Boca Raton, Florida, v. 61, 1980 Comment: density=31-35 ppcf (0.50-0.56 g/cm3)
* Marja-Sisko Ilvessalo-Pfäffli. Fiber Atlas: Identification of Papermaking Fibers (Springer Series in Wood Science). Springer, 1995. 
* Walter Rantanen. "Fiber ID Course." Integrated Paper Services. June 2013. Lecture.
Category:Materials database
Lard

== Description ==
The purified fat from hogs (Sus scrofa). Lard is soft, white material with a characteristic odor that is primarily composed of stearin, palmitin, and olein. The oil expressed from lard, called lard oil, contains the fatty acids of these lipids with the following composition (average %): oleic acid (47.5), palmitic acid (28.30), stearic acid (11.9), linoleic acid (6.0) and myristic acid (1.3) (CRC Handbook 1980). Purified lard, also called adeps, is used for food products and cooking grease. Lard is also used for ointments, lubricants, soaps, candles, and leather dressing. Lard was once used as a substitute for butter in cooking and frying due to its which melting point.
== Synonyms and Related Terms ==
reuzel (Ned.); ister (Sven.); manteca (Esp.); lardo (It); adeps; lard oil; animal fat 
== Risks ==
* Combustible.
==Physical and Chemical Properties==
Soluble in benzene, chloroform, ether, carbon disulfide, ligroin. Slightly soluble in ethanol. Insoluble in water. 
For lard oil: iodine value = 58.6 and saponification value =194.6
Melting Point 	36-42 C
Density 	0.917 g/ml
Refractive Index	1.4615 (lard oil)
==Resources and Citations==
* G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 437
* Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
* The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 5380
* Wikipedia: http://en.wikipedia.org/wiki/Lard (Accessed Jan. 6, 2006)
* CRC Handbook of Chemistry and Physics, Robert Weast (ed.), CRC Press, Boca Raton, Florida, v. 61, 1980
Category:Materials database
Larder beetle

== Description ==
A black beetle, Dermestes lardarius, that has a distinctive yellow band across the base of its wing. The universally found larder beetle larvae feed on animal matter, including leather, fur, feathers, horn, and carcasses. The larvae may also damage to cellulose materials. The adult insects are 7 to 9 mm long and have a life span of up to 1.5 years. The brownish-yellow larvae have a fine line down the center of its abdomen. The larvae can grow to 12 mm in length. The larval period lasts from 15 to 80 days.
== Synonyms and Related Terms ==
Dermestes lardarius
== Additional Images ==
File:5312060_Larder.beetle_adult.ovr.jpg|Larder beetle
File:5312065_Larder.beetle_adult.side.jpg|Larder beetle
File:2154075_Larder.beetle_adult.jpg|Larder beetle
==Resources and Citations==
* MuseumPests.net: Larder Beetle
* Lynda A. Zycherman, J.Richard Schrock, A Guide to Museum Pest Control, FAIC and Association of Systematics Collections, Washington DC, 1988
* Rosalie Rosso King, Textile Identification, Conservation, and Preservation, Noyes Publications, Park Ridge, NJ, 1985
Category:Materials database
Laropal A-81

== Description ==
[BASF] A trademark for low molecular weight urea-aldehyde resin. Laropal A-81 is used as a base material in Gamblin Conservation Colors retouching paint. The low molecular weight resin is soluble in low polarity solvents and is said to have working properties similar to natural resins.
==Resources and Citations==
* BASF: for Technical Info and MSDS
* R.de la Rie, S.Q.Lomax, M.Palmer, L.D.Glinsman, C.Maines, "An Investigation of the Photochemical Stability of Urea-aldehyde Resin Retouching Paints" International Institute for Conservation, Melbourne Congress, 2000. 
* J.M.Arslanoglu, T.Learner, "The Evaluation of Laropal A81: Paraloid B-72 Blend Varnises for Painted and Decorative Surfae:Optical and Aesthetic Properties" The Conservator v.25, UKIC, 2001.
Category:Materials database
Laropal K-80

== Description ==
[BASF] A trademark for a polycyclohexanone resin introduced in 1979 as a replacement for Ketone Resin N. Laropal K-80 is prepared by the polycondensation of cyclohexanone in a continuous process. Polycyclohexanones resemble dammar in that they are soluble in turpentine and form a glossy, colorless coating. However, they are harder and exhibit less wrinkling, blooming, and yellowing than natural resins. Because polycyclohexanone coatings are hard, however, many formulations add a plasticizer for flexibility and many of the plasticizers tend to yellow. Additionally, polycyclohexanones oxidize, become brittle, and less soluble with age. They have been used for retouching and occasionally for picture varnishes.
==Physical and Chemical Properties==
Soluble in petroleum hydrocarbons, turpentine, isopropanol. Insoluble in water and methanol. Partially soluble in ethanol.
Tg 	50.8 C
Refractive Index	1.529
==Resources and Citations==
* BASF: for Technical Info and MSDS
* R. Cox, "Ketone Resin Varnishes" AIC Painting Conservation Catalog, Varnishes and Surface Coatings, p. 75, 1998
* Conservation Materials Ltd., Catalog
* Teri Hensick, contributed information, 1998
* Comment: www.hants.org.uk/museums/ofr/cmeth_t.html (Note: this website is no longer active)
Category:Materials database
Lascaux Acrylic Adhesive 303 HV

== Description ==
[Alois K Diethelm, Switzerland] A trademark for a thermoplastic acrylic resin composed of a water-based dispersion of butyl acrylate and methylmethacrylate thickened with acrylic butylester. The minimum film formation temperature for Lascaux Acrylic Adhesive 303 HV is approximately 0°C. It dries to form a film that is more flexible and elastic than 498HV. The dry film is slightly tacky and can be used as a weak pressure sensitive adhesive or it can be activated to improve adhesion with toluene, alcohol or heat (50-55°C). The emulsion can be thinned with water, but once the film is dried it is insoluble in water. Lascaux 303 HV is used as an adhesive for lining paintings and textiles. Velagadapudi et al.(2023) tested its potential for temporarily mounting small objects and found it showed potential as a replacement for Rhoplex N-580 that was discontinued in 2019.
Lascaux 303 HV is manufactured as a replacement for Lascaux 360 HV that was discontinued in 2012.
==Risks==
* Talas: SDS sheet
==Physical and Chemical Properties==
* Dry films: Soluble in acetone, ethanol, toluene and xylene. Insoluble in water, white spirit and ligroin.
* Min film formation temp (MFT): approx. 0 degrees C.
* Glass Transition temperature (Tg): approx. -28 degrees C.
* Elongation at break: approx. 1000%
* Minimum sealing temp: approx. 50 degrees C.
* Dry film consistency: Sticky, clear
==Resources and Citations==
* Neeha Velagapudi, Emily Fryer, Sarah Murray, Kristen Ramsdale, Sebastian Denize, Sam Adshead, 'Finding a Temporary Adhesive for Securing Objects for Display in Earthquake-prone Regions' Studies in Conservation, 68(1), 36-42, 2023 link
* Talas: Lascaux 303HV 
Category:Materials database
Lascaux Acrylic Adhesive 360 HV

== Description ==
[Alois K Diethelm, Switzerland] A trademark for a thermoplastic acrylic resin composed of a water-based dispersion of butyl acrylate and methylmethacrylate thickened with acrylic butylester. The minimum film formation temperature for Lascaux Acrylic Adhesive 360 HV is approximately 0°C. It dries to form a film that is more flexible and elastic than 498HV. The dry film is slightly tacky and can be used as a weak pressure sensitive adhesive or it can be activated to improve adhesion with toluene, alcohol or heat (50-55°C). The emulsion can be thinned with water, but once the film is dried it is insoluble in water. Lascaux 360 HV is used as an adhesive for lining paintings and textiles.
Lascaux 360 HV was discontinued in 2012. Lascaux 303 HV is manufactured as a replacement.
==Physical and Chemical Properties==
* Dry films: Soluble in acetone, ethanol, toluene and xylene. Insoluble in water, white spirit and ligroin.
* Tg = -8C
==Resources and Citations==
* Talas: Information sheet 
* J. Down, M.MacDonald, J.Te'treault, S.Williams, Adhesive Testing at the Canadian Conservation Institute-An Evaluation of Selected Poly(Vinyl acetate) and Acrylic Adhesives", Studies in Conservation 41:19-44, 1996. 
* D.Allard, K.Katz "Quantitative Study: The Effects of Sized Materials and Drying Time in the Use of Lascaux 360HV as a Lining Adhesive: JAIC 26;19-26, 1987
* Book and Paper Group, Paper Conservation Catalog, AIC, 1984, 1989
* Manufacturer's literature: glass transition= -8; sealing point= 50-55C
* Marie Svoboda, Conservation Survey Index, unpublished, 1997
* Gordon Hanlon, contributed information, 1998
* Meredith Montague, contributed information, 1998
* Teri Hensick, contributed information, 1998
* Conservation Materials Ltd., Catalog
* Conservation Support Systems, Catalog, 1997
Category:Materials database
Lascaux Acrylic Adhesive 498 20X

== Description ==
[Alois K Diethelm, Switzerland] A trademark for a thermoplastic acrylic resin composed of a water-based dispersion butyl acrylate and methylmethacrylate thickened with acrylic butylester. Lascaux Acrylic Adhesive 498 20X can be thinned with water, but once the film is dried it is insoluble in water. The minimum film formation temperature for 498 20X is approximately 5°C and its initial tack is faster that 498 HV. A dry film is slightly tacky and can be used as a weak pressure sensitive adhesive or it can be activated to improve adhesion with toluene, alcohol or heat. Lascaux Acrylic Adhesive 498 20X is used as an inpainting media.
==Physical and Chemical Properties==
* Dry films: Soluble in acetone, ethanol, toluene and xylene. Insoluble in water, white spirit and ligroin.
* Lascaux 498-20X contains 20% Thinner X
* Tg=26 C
==Resources and Citations==
* Talas: Information sheet
* Book and Paper Group, Paper Conservation Catalog, AIC, 1984, 1989
* Product Information Comment: manufacturer's lit states composed of butyl acrylate, thickened with 20% toluene; glass transition = 26C
* Marie Svoboda, Conservation Survey Index, unpublished, 1997
* Gordon Hanlon, contributed information, 1998
* Meredith Montague, contributed information, 1998
* Teri Hensick, contributed information, 1998
* Conservation Materials Ltd., Catalog
* Conservation Support Systems, Catalog, 1997
Category:Materials database
Lascaux Acrylic Adhesive 498 HV

== Description ==
[Alois K Diethelm, Switzerland] A trademark for a thermoplastic acrylic resin composed of a water-based emulsion containing butyl acrylate thickened with methacrylic acid (40% solids). Lascaux Acrylic Adhesive 498 HV can be thinned with water, but once the film is dried it is insoluble in water. The minimum film formation temperature for 498 HV is approximately 5C. A dry film is slightly tacky and can be used as a weak pressure sensitive adhesive or it can be activated to improve adhesion with toluene, alcohol or heat (75C). Lascaux Acrylic Adhesive 498 HV has been used for lining and mounting canvases, paper, wood and plaster.
==Physical and Chemical Properties==
* Dry films: Soluble in acetone, ethanol, glycol esters, toluene and xylene. Insoluble in water, white spirit and ligroin.
* Tg = 26 C
==Resources and Citations==
* Talas: Information sheet
* Book and Paper Group, Paper Conservation Catalog, AIC, 1984, 1989
* Marie Svoboda, Conservation Survey Index, unpublished, 1997
* Meredith Montague, contributed information, 1998
* Teri Hensick, contributed information, 1998
* Conservation Materials Ltd., Catalog
* Conservation Support Systems, Catalog, 1997
Category:Materials database
Lascaux Hydrosealer 750

== Description ==
[Alois K Diethelm, Switzerland] A trademark for a thermoplastic acrylic composed of fine styrene acrylate particles (0.06 micrometers) in a 30% solids aqueous dispersion. Lascaux Hydrosealer 750 is used for consolidation of friable and cupping paint. For use with oil paints, the manufacturer recommends the addition of a wetting agent (0.1%) to increase penetration of the consolidant.
[[[SliderGallery rightalign|Hydroseal 750.PNG~FTIR]]]
== Synonyms and Related Terms ==
Lascaux Hydroseal 750
==Physical and Chemical Properties==
* Aqueous dispersion: pH = 9-10 
* Dry film: Soluble in acetone, ethanol, toluene and xylene. Insoluble in water.
==Resources and Citations==
* Marie Svoboda, Conservation Survey Index, unpublished, 1997
* Teri Hensick, contributed information, 1998
* Conservation Materials Ltd., Catalog
* Conservation Support Systems, Catalog, 1997
* Product Information Comment: manufacturer's literature
Category:Materials database
Lascaux Welding Powder

== Description ==
[Alois K Diethelm, Switzerland] A trademark for a hot-melt adhesive composed of nylon 12 thermoplastic resin. Lascaux Welding Powder #5065 is used for mending tears in textile, canvas, and leather products.
== Synonyms and Related Terms ==
Lascaux Polyamide Textile Welding Powder No. 5065
==Physical and Chemical Properties==
* Melting Point = 90-100 C
==Working Properties==
* Easiest application is to stick a hot soldering needle into the powder and then apply the melted polyamide. 
* An alternative consists of melting the polyamide powder with an iron between two sheets of silicone coated polyester film, in order to obtain a coat of approx. 1-2 mm thickness. After cooling, the polyamide coat is cut in very thin strips. These strips are then used together with the soldering needle to weld the threads.
==Resources and Citations==
* Talas: Lascaux welding powder
* Conservation Support Systems, Catalog, 1997
Category:Materials database
Laser

== Description ==
Originally an acronym for light amplification by stimulated emission of radiation. Common usage, however, has applied the term laser to any of several devices that convert a wide range of electromagnetic frequencies into one coherent frequency. This is done by exciting the atoms to reach a higher energy level where their wavelengths are in a single phase. The resultant laser beam has extremely intense energy. Lasers, first patented in 1960 by Bell Labs, have now been made using ultraviolet, visible, infrared, and microwave wavelength regions. Lasers are used in communication (optical fibers, satellites), medicine (surgery), spectroscopy (FT-IR, Raman, mass spectrometry), photography (holography) and for geographical mapping in difficult locations (planets, moon, ocean floor). Lasers have been used to remove encrustations, overpaint, soot, stains, fungi, and graffiti from several types of surfaces (Asmus 1978 and 2000). 
See also laser pointer.
== Synonyms and Related Terms ==
laser (Dan., Deut., Fr., It., Ned., Nor., Pol., Port., Sven); láser (Esp.);
== Risks ==
Can irreparably damage the eyes.
== Physical and Chemical Properties ==
Classifications:
* Class 1: Safe for use in most anticipated exposure conditions
* Class 2: Visible light laser whose prolonged viewing is dangerous to the human eye
* Class 3B: Direct viewing of beam is hazardous, diffusely reflected beam should not be hazardous
* Class 4: High power lasers that are hazardous to eyes and skin at all times
== Resources and Citations ==
* J.Asmus, "Light Cleaning: Laser Technology for Surface Preparation in the Arts", Technology & Conservation, 3/78, p. 14-18.
* J.Asmus, Workshop on Laser Cleaning, AIC meeting, Philadelphia, June 2000.
* Encyclopedia Britannica, http://www.britannica.com Comment: "laser" [Accessed 25 Jan. 2006].
* Laser Classifications at: http://ptcl.chem.ox.ac.uk/MSDS/laser_classification.html
* Wikipedia: http://en.wikipedia.org/wiki/Laser (Accessed Sept. 28, 2005)
* Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
* Hoechst Celanese Corporation, Dictionary of Fiber & Textile Technology (older version called Man-made Fiber and Textile Dictionary, 1965), Hoechst Celanese Corporation, Charlotte NC, 1990
* Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
* Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
* The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
Category:Materials database