NEW MATERIALS DATING TO THE TURN OF THE 13th-18th CENTURIES FROM THE 2020 EXCAVATIONS OF THE ZAT’MATSKIY POSAD IN TVER

В статье рассматриваются новые материалы, полученные в результате исследований на Затьмацком посаде Твери археологической экспедицией ТвГУ в 2020 г. Открыты комплексы с находками рубежа XII-XIII - XIV вв. Состав ранних находок идентичен выявленному ранее в раскопе 81: височные кольца, ромбовидная подвеска, линейнопрорезной бубенчик, стеклянные браслеты, бронзовые пластинчатые и витой браслеты и др. К XV-XVII вв. относится серия предметов личного благочестия и бытовые предметы. Выявлены находки, свидетельствующие о близости ювелирного производства в XV-XVI вв.: литейная форма, отливка крестика, обломки проволоки. Характер культурного слоя и сооружений свидетельствует о том, что исследованная территория являлась хозяйственной периферией по отношению к жилым и производственным комплексам усадеб XIII-XIV и XV-XVI вв., открытым в соседних раскопах 56, 81, 24. Направление частокольных канавок соответствует ориентации усадебных комплексов Затьмачья и свидетельствует о включенности этой территории в единую усадебно-уличную планировку посада в XVXVII вв., а возможно, и ранее. The paper explores new materials obtained through excavations of the Zat’matskiy posad (suburb) in Tver conducted by the Tver State University archaeological expedition in 2020. The excavations discovered assemblages containing finds from the turn of the 13th-18th centuries. The composition of the earlier finds is identical to that of the assemblage discovered in excavation trench 81: temporal rings, a rhomboid pendant, a bell with a linear slot on the bottom, glass bracelets, bronze plated bracelets and one twisted bracelet, etc. A series of items of personal piety and household goods refer to the 15th-17th centuries. There are finds that demonstrate characteristics typical of jewelry production in the 15th-16th centuries: a casting mold, a cast baptismal cross, and fragments of wire. Distinctive features of the occupation layer and constructions indicate that the excavated area was located on the periphery of residential and production buildings of the town estates dating to the 13th-14th centuries and the 15th-16th centuries discovered in adjacent excavation trenches 56, 81, and 24. The location of palisade ditches is consistent with the orientation of the estate ensembles in the Zat’matskiy area suggesting that this area was part of the estatestreet layout of the suburb in the 15th-17th centuries, and maybe even earlier.

Comparison of the Flow Field in a Slab Continuous Casting Mold between the Thicknesses of 180 mm and 250 mm by High Temperature Quantitative Measurement and Numerical Simulation

In the present work, the flow field in a slab continuous casting mold with thicknesses of 180 and 250 mm are compared using high temperature quantitative measurement and numerical simulation. The results of the numerical simulation are in agreement with those of the high temperature quantitative measurement, which verifies the accuracy and reliability of the numerical simulation. Under the same working conditions, the velocities near the mold surface with the thickness of 180 mm were slightly higher than those of the mold with the thickness of 250 mm. The flow pattern in the 180 mm thick mold maintains DRF more easily than that in 250 mm thick mold. The kinetic energy of the jet dissipates faster in the 250 mm thick mold than in the 180 mm mold. For double-roll flow (DRF), as the argon gas bubbles can be flushed into the deeper region under the influence of strong jets on both sides, the argon bubbles distribute widely in the mold. For single-roll flow (SRF), as the argon bubbles float up quickly after leaving the side holes, the bubble distribution is more concentrated in the width direction, which may cause violent interface fluctuation and slag entrainment. The fluctuation at the steel-slag interface in the mold with 180 mm thickness is greater than that in the mold with 250 mm thickness but less than 5 mm. The increase of mold thickness may lead to a decrease of the symmetry of the flow field in the thickness direction and uniformity of mold powder layer thickness. In summary, the steel throughput should be increased in the 250 mm thick mold compared with that in the 180 mm thick mold.

The Chemical Composition of the Medieval Mirrors from Golden Horde Time Settlements

Introduction. The paper discussed the results of the study concerning the chemical composition of 16 mirrors from the Golden Horde period originating from the settlements Selitrennoe, Vodyanskoe, Uvekskoe Khmelevskoe I, Shirokiy Buerak and stored in the State Historical Museum (Moscow) and Saratov Regional Museum of Local Lore (Saratov). Method. The visual inspection of the items was carried out using the traceology method, XRF and SEM/EDS were used as a method of determining the elemental composition. To compare the results, data on the chemical composition of mirrors originating from other medieval sites in Eastern Europe were used. Analysis and Results. All but one mirror, made with a stone casting mold, were cast using the impression method. Some of the mirrors show traces of post-casting processing. Several types of alloys have been identified. Most of the mirrors were made of tin-lead bronze (7 items) with an increased (more than 20 %) tin content, which correlates with the results obtained on samples from other settlements of the pre-Horde and Horde times. Other large groups are mirrors made from multicomponent (3 items) and tin bronze (4 items). One mirror each is made of tin brass and lead bronze with the addition of arsenic. Mirrors with arsenic in their composition are also known from other samples from a nomadic cemetery of the Golden Horde period and settlement monuments, which indicates a sufficiently active existence of a more archaic metal in the 14th century.

EFFECT OF ALUMINUM CONTENT ON THE HARDNESS AND MACHINABILITY OF BRASS ALLOY USED IN OXYGEN CYLINDER VALVE

There is high consumption of oxygen cylinder valves due to incorrect application of valves, therefore, this research will study the possibility to modify Brass alloy that used to produce cylinder valves and reduce their erosion that happens under the use of valve. The main type of brass that used to make cylinder valve is CW713R which contained aluminum with percentage of 1.3-2.3% with hardness of 174 HV. Therefore, the effect of aluminum element on the properties of brass alloy will study to find the best and the optimum percentages that can be added to improve the hardness and machinability of cylinder valve. Brass scrap was melted using oil fire furnace and aluminum element was added before it cast. Then, the melting liquid was poured on steel die casting mold. The result shows that the hardness Brass cylinder valve was increased by increasing the percentage of aluminum element. It is raised from 206 to 605 HV. But when the percentage of aluminum reached 10 % the Brass material becomes brittle and difficult to machine. The best percentage of aluminum that can be added to brass alloy lies in the range of 2.5 – 5%.