Asta de corzo como materia prima en el Período Huno-Sármata en el norte de Altái

Antler of Cervidae was an important part of the raw material base in traditional manufacturing in Northern Altai during the Hunno-Sarmatian period (the first half of the 1st millennium CE). Several seasonal migration routes of the roe deer cross this territory. The processing of roe deer antler during the Hunno-Sarmatian period is well documented at several archaeological sites in the inter-mountain valley of the lower Katun River. The assortment of antler products is composed inter alia of tools, composite bow elements, arrowheads and horse harnesses. The natural occurrence and high quantity of the specific antler material affects differences in the technology of manufacture. Generally, the assortment of antler items of the Hunno-Sarmatian period from the Northern Altai is typical of the broader region of Southern Siberia, Central Asia and the forest steppes of Eastern Europe.  El asta de cérvido ocupó un importante lugar como materia prima dentro del proceso de manufatura tradicional en la zona norte de Altái durante el Período Huno-Sármata (primera mitad del I milenio DC). Diversas rutas migratorias estacionales de corzos atraviesan este territorio. El procesamiento del asta de corzo durante el Período Huno- Sármata está bien documentado en varios yacimientos arqueológicos en el valle del curso bajo del Katun. El surtido de productos está compuesto, entre otros, por herramientas, elementos compuestos para arco, puntas de fleche y harneses de caballo. Laoccurrencia natural y gran cantidad de material específico de asta afecta a diferencias en la tecnología empleada para la manufactura. Generlmente, el conjunto de elementos de asta del Período Huno-Sármata del norte de Altái es típica de una región más amplia que abarca parte del sur de Siberia, Asia Central y las estepas boscosas del Este de Europa

A METHOD FOR THE ASSESSMENT OF THE ROLLING CONTACT FATIGUE OF MODERN ENGINEERING MATERIALS IN LUBRICATED CONTACT

It is widely recognised that apart from scuffing, rolling contact fatigue (RCF) is one of the most predominant failure types in highly loaded non-conformal friction joints. The fatigue life of machine parts depends on many factors that can be divided into three groups: design, technology and operating conditions. The main factors influencing pitting are material properties, the geometry of the tribosystem, surface finish, dimensional precision, and working conditions as well as the physicochemical properties of the lubricant. The aim of this paper is to present the experimental method for determining fatigue life of modern engineering materials in lubricated rolling contact. The developed method allows an investigation into the effect of all these factors on rolling contact fatigue (pitting). The method is employed by using a modified four-ball testing machine denoted as T-03. The modification embraces the replacement of testing specimens. The upper ball is replaced with a cone that can be made of various materials. The method exhibits good resolution and is time and cost effective. It was successfully applied to the investigation into various types of surface coatings including single, multilayer and duplex coatings. This method can be employed by using a widespread four-ball apparatus

Low-frequency noise measurements of IR photodetectors with voltage cross correlation system

Abstract The paper presents a system for noise measurements in infrared photodetectors characterized by low shunt resistances based on a two-channel ultra-low-noise voltage amplifier with paralleled discrete JFETs at the input stages. Using cross correlation method, a background noise well below of 10−19 V2/Hz can be obtained at frequencies above 10 Hz. To facilitate the estimation of the noise in such a wide frequency range (5 decades), we also developed a software based on the QLSA library. As a result of these efforts, the equivalent input voltage noise of the system is below 10−19 V2/Hz at 10 Hz and 10−20 V2/Hz for frequencies above a few hundred Hz. The system effectiveness is demonstrated by noise measurements at room temperature on advanced InAsxSb1-x photodetectors characterized by an active area of 1 mm2 and a shunt resistance below 10 Ω

Identifying seasonal settlement sites and land use continuity in the prehistoric southern Siberian steppe – Zhelvak 5 (Tuva)

The identification of camp sites of Iron Age cultures on the Eurasian steppes has long been a problem as the traces of seasonal settlements are faint and often destroyed by agricultural activities. Recent research has found increasing evidence for less mobility and a larger role farming played in the mixed and locally adapted economies of peoples on the steppes. Here we present the results of the investigation of a settlement from the Uyuk Valley and contextualize it with data for seasonal camp sites and settlements in Iron Age South Siberia. Contrary to the long-held beliefs that Iron Age herding societies were truly nomadic and did not establish permanent settlements, archaeological research in South Siberia is gradually starting to reveal a different picture. Remote sensing and on-ground surveys uncovered six Scythian-period settlement sites in Tuva occupying southern hill slopes in sheltered topographic settings. Excavations at Zhelvak 5 revealed a stratified site with materials from the Bronze Age to the Late Iron Age and beyond. The archaeological material speaks towards continuity of economic exploitation of this landscape and the establishment of seasonal camp sites in the same place over a prolonged period of time

Testing of the Resistance to Scuffing of Spiral Bevel Gears: Test Rig, Method, and Results of Verification Testing

In spite of long-term development of the technology of bevel gear production, the automotive industry reports various operational demands such as the need of the size and mass reduction of gears without lowering their durability and reduction of friction leading to a decrease in the energy losses and a decrease of the tendency to scuffing. What is more expected, EU regulations may impose the use of new generation gear oils (ecological-friendly) providing the proper operational properties of the transmission. In view of these demands, a new, bevel gear test rig and scuffing test method have been developed at ITeE-PIB. The idea resulted from a necessity to improve reliability of tests—popular gear tests are run mostly on spur gears having the tooth geometry significantly different than bevel gears. The test rig, test method, and results of verification testing are presented. The effect of various gear oils and the deposition of a low-friction coating on the resistance to scuffing were investigated. It is shown that the new test rig fulfils the research requirements and that the new test method has a good resolution

A METHOD FOR THE ASSESSMENT OF THE ROLLING CONTACT FATIGUE OF MODERN ENGINEERING MATERIALS IN LUBRICATED CONTACT

It is widely recognised that apart from scuffing, rolling contact fatigue (RCF) is one of the most predominant failure types in highly loaded non-conformal friction joints. The fatigue life of machine parts depends on many factors that can be divided into three groups: design, technology and operating conditions. The main factors influencing pitting are material properties, the geometry of the tribosystem, surface finish, dimensional precision, and working conditions as well as the physicochemical properties of the lubricant. The aim of this paper is to present the experimental method for determining fatigue life of modern engineering materials in lubricated rolling contact. The developed method allows an investigation into the effect of all these factors on rolling contact fatigue (pitting). The method is employed by using a modified four-ball testing machine denoted as T-03. The modification embraces the replacement of testing specimens. The upper ball is replaced with a cone that can be made of various materials. The method exhibits good resolution and is time and cost effective. It was successfully applied to the investigation into various types of surface coatings including single, multilayer and duplex coatings. This method can be employed by using a widespread four-ball apparatus