Mortars development

Panzerwurfkannone. A Ger smooth-bore 80mm mortar developed during WWII by Rheinmetall for firing hollow-charge projectiles at longer ranges than the Panzerschreck or Panzerfaust. 

Stokes Mortar The 4 in. Stokes mortar developed for chemical agent delivery was first fielded by the British in September 1915 at Foos, and was in wide use by the Somme battles of 1916 this represented the first use of projectiles filled with lethal chemicals in World War I. Chemical artillery shells (or projectiles ) and mortars remained in chemical arsenals throughout the twentieth century. During World War I, the Germans produced chemical agent-filled projectiles for 77, 105, and 150 mm artillery pieces,... 

The 4 in. Stokes mortar developed for chemical agent delivery, first fielded in September 1915 at Loos this represented the first use of projectiles filled with lethal chemicals in World War I. 

The British Livens Projector was a large-scale mortar developed for delivering large amounts of chemical warfare agent. 

Dri-lok. Tradename. A method for the quick and precise construction of kiln cars using interlocking insulating bricks without mortar. Developed by MPK Insulation, Colchester, the Dri-lok bricks are 230 x 114mm or 230 x 230mm, up to 114mm thick. 

In 1916 the British introduced a new means of projecting gas, the 4-inch Stokes mortar, developed from the 3-inch version of this weapon, which had been the standard mortar in the British Army. Because of their inability to manufacture gas shells, the British first used the mortar to fire improvised smokes and incendiaries. The Stokes gas shell, or bomb, as the British called it, contained six pounds of agent as compared to three pounds for the British 4.5-inch heavy howitzer shell. 

Ltr, Maj Gen Amos A. Fries to TAG, 17 Apr 28, sub Adoption as to Type, with inds. CWS 400.114/280. (2) 4.2-Inch Chemical Mortar, a monograph in series, History of Research and Development of the CWS in World Wat II. (3) An excellent review of all phases of mortar development from World Wat I to 1945, is George A. Millet, "The Development of the 4.2-Inch Chemical Mortar," Armed Forces Chemical journal, III (October 1948), 33-42 III (January 1949) 35-42. 

Lt G. E. McCullough, Engineering Test of 4.2-Inch Chemical Mortar Shell Experimental—Manufactured by the Scaife Company. TDMR 348, 11 Feb 42. (2) Charles T. Mitchell, Outline of 4.2-inch Chemical Mortar Development, p. 66. ETF 218-26, 22 Feb 45. 

Based on the technology developed for using PVA fiber as a replacement for asbestos in cement products, Kuraray has been developing thick fibers for reinforcing concrete (42). Super-thick fibers with a thickness of 39 tex (350 den) (200 p.m in diameter) to 444 tex (4000 den) (660 p.m in diameter) are now available the 39 tex material is used for reinforcing various mortar-based cement products and the 444 tex material for reinforcing concrete in civil engineering works such as tuimels, roads, harbors, and bays. 

Although the use of simple diluents and adulterants almost certainly predates recorded history, the use of fillers to modify the properties of a composition can be traced as far back as eady Roman times, when artisans used ground marble in lime plaster, frescoes, and po22olanic mortar. The use of fillers in paper and paper coatings made its appearance in the mid-nineteenth century. Functional fillers, which introduce new properties into a composition rather than modify pre-existing properties, were commercially developed eady in the twentieth century when Goodrich added carbon black to mbber and Baekeland formulated phenol— formaldehyde plastics with wood dour. 

Roofs are a basic element of shelter from inclement weather. Natural or hewn caves, including those of snow or ice, ate early evidence of human endeavors for protection from the cold, wind, rain, and sun. Nomadic people, before the benefits of agriculture had been discovered and housing schemes developed, depended on the availabiUty of natural materials to constmct shelters. Portable shelters, eg, tents, probably appeared early in history. Later, more permanent stmctures were developed from stone and brick. SaUent features depended strongly on the avadabihty of natural materials. The Babylonians used mud to form bricks and tiles that could be bonded with mortars or natural bitumen. Ancient buildings in Egypt were characterized by massive walls of stone and closely spaced columns that carried stone lintels to support a flat roof, often made of stone slabs. 

The sodamide must be free from sodium hydroxide and may be conveniently weighed under the 250 cc. of purified mineral oil which is used to rinse out the mortar. Care must be exercised in the use of old sodamide as it sometimes contains an explosive compound that might cause trouble. The nature of this explosive compound is not definitely known however, it appears to be associated with the development of a lemon yellow color. Should any part of the sodamide develop this color it is recommended that the whole be destroyed at once. 

Lead is relatively easily corroded where acetic acid fumes are present and under such conditions it either should not be used or should be efficiently protected. Generally, any contact between lead and organic material containing or developing acids will cause corrosion for instance, unseasoned wood may be detrimental. Trouble from this cause may be prevented by using well-seasoned timber, by maintaining dry conditions, or by separating the lead from the timber by bitumen felt or paint. Lead is also subject to attack by lime and particularly by Portland cement, mortar and concrete, but can be protected by a heavy coat of bitumen. A lead damp-proof course laid without protection in the mortar joint of a brick wall may become severely corroded, especially where the brickwork is in an exposed condition and is excessively damp. 

Figure 6.9 The morphology of a commercial mortar, showing well-developed needle-like crystallites. Micrograph span (a) 75 pm, (b) 30 pm (Abdelrazig er at., 1984).

Microstructure is also affected by water content. The 1 16 mortar contained hexagonal plates, while the 1 8 mortar had an ellipsoidal morphology. The 1 5 mortar when prepared at — 5 °C developed striking, well-formed, needle-like crystals (Figure 6.9). 

Mortar specimens were prepared to determine the effectiveness of MRI in a time resolved lithium penetration experiment [15]. This work used a non-reactive aggregate and commercially available LiN03 solution to simulate topical treatments to concrete. These results will aid the development of a more general measurement of concrete core extracted from a lithium treated structure suffering from ASR. 

Ambroise, J., Amoura, A., and Pera, J., Development of flowable high volume - fly ash mortars, in Proceedings of the 11th International Symposium on the Use and Management of Coal Combustion Byproducts (CCBs), Vol. 2, American Coal Ash Association, 1995. 

In the ballistic mortar test the explosive is well confined and develops... 

The first offensive weapons used by man were probably stones, and similarly the first objects thrown when mortars were developed were solid, usually spherical, balls of stone or iron. With the development of explosives it was soon realised that it would be more effective to use a hollow missile filled with explosive, designed to burst in the middle of the enemy. Gunpowder was originally used as filling, but has now been completely superseded by high explosives. 

Environment and health-related problems Water-soluble chrome(VI) compounds in the wet cement or mortar have a highly sensitising effect and are up to 90% the cause of allergic cement dermatitis (cement eczema, bricklayer s itch ). The high alkalinity (pH = 13) of cement aids the development of this contact eczema. Bricklayer s itch is one of the most frequent professional diseases in the construction industry. 

Of these, the most successful appeared in 1887 when Alfred Nobel patented a nitrocellulose propellant plasticised with nitroglycerine. Known as a double-base propellant, it is virtually smokeless, with a very high specific impulse as compared to gunpowder. Single-base propellants were developed in 1865 and 1890 by Schultz and Vieille respectively and these took the form of gelatinised nitrocellulose for use in firearms and mortars. 

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