Investigations at the Trypillia settlement near Hlybochok village in Cherkasy Oblast

The Trypillia settlement is located at the western edge of Hlybochok village (former Zvenyhorodka district of Cherkasy Oblast), at the plateau of the western bank of the Hirskyi Tikych River. According to the geophysical surveys, the settlement size reached 100 ha. Its dwellings were organized into two ellipses. The remains of two dwellings (ploshchadki) were excavated in 1994—1995. Ploshchadka No. 1 was located in the southern part of the external construction ellipse, while ploshchadka No. 2 was located in the second internal ellipse at the eastern part of the site. The remains of both houses had a rectangular shape and included several layers of burnt clay. Houses had fireplaces on the lower storey. The second house also included an elevation of rectangular shape with grinding stones. Living areas are associated with the upper storey of houses. The majority of materials, mainly kitchen and table pottery, were found between the layers of burnt clay. Kitchen pottery (6—7 %) is represented by conical bowls and pots with S-shaped profiles with poor ornamentation. Table pottery (92—93 %) is represented by ceramics ornamented with black monochromic painting. Nearly 45 % of pottery forms and 25 % of ornamentation schemes were reconstructed. Ceramic shapes are represented by bowls, goblets, biconical, spherical and conical vessels, amphorae, pear-shaped vessels, leads, craters, pots and binocular-shaped vessels. Anthropomorphic figurines were found in fragments. The Hlybochok settlement is referred to the late phase of Nebelivska group (the end of BII period) of the development of the Western Trypillia culture. The settlement is dated to the range of 3925—3825 BC. The Nebelivska group marks the migration of the Western Trypillia culture populations to the north-eastern direction, towards the Middle Dnieper region. Its further development between the Ros and the Dnieper rivers resulted in the formation of Kanivska local group, which pottery is also characterized by the influence of the Eastern Trypillia traditions. In the indigenous area the Nebelivska local group was replaced by the Tomashivska group.

Desalination using clay and lime sacrificial plasters with additives on field stone wall and fired clay bricks

Salt deteriorations can ruin the appearance as well as the structure of buildings. Salt deteriorations can be mitigated by passive and active methods. Common active methods include sprinkling water on the structure, scraping off the concentrated salts from the surface and the use of sacrificial plasters. Sacrificial plasters are traditionally used for desalination. Two tests at different sites were performed in order to determine the effectiveness of desalination of different sacrificial plasters. The first test site was a two hundred years old stable wall in Mooste county, Estonia. Salt percentage by mass in the test wall was determined in 2017 and again in 2019. In December 2019 different plasters of local natural clay and lime with additives such as hemp flax, charcoal and turf were tested on the wall. The second test was performed on burnt clay bricks that were placed into salt solution until efflorescence appeared. For desalination process again, different clay and lime based sacrificial plasters were used. After removing the sacrificial plaster, samples from the mortar and bricks were taken to measure the salt content by using Ion chromatography. Clay and hemp flax based sacrificial plasters were the most suitable for desalination and removal.

Properties of locally available river dredged soil stabilized with cement

In Bangladesh, the topsoil of agricultural land is being used to manufacture burnt clay bricks for a long time. This is one of the major reasons for reducing the cultivable land every year. But, we have a huge amount of River Dredged Soil (RDS) available that could be used for manufacturing building materials as an alternate to the conventional bricks. In this regard, the present study has been performed to investigate various properties of RDS from the Brahmaputra River and different mixes of RDS containing different percentages of cement content. The physical properties such as specific gravity, unit weight, mean diameter, maximum dry density and optimum moisture content of RDS were determined following standard procedures. Cylindrical specimens of RDS were prepared by mixing with different amounts of cement content. All the specimens were cured for 7, 14, and 28 days before testing. Water absorption of the RDS-cement specimens after 28 days was found between 14 to 18% which is in the range of first-class burnt clay brick. It was found that the water absorption decreases with the increase in the percentages of cement content. The unconfined compressive strength was observed to increase with the increment of cement content as well as curing age. The maximum unconfined strength was recorded for the specimens containing 14% cement and the rate of strength increment was about 45% in two weeks. It means the addition of cement with RDS will definitely increase the strength. But, the maximum use of cement must be decided based on the required strength and economic consideration. The deformation at failure was found decrease with the increase in cement content. This indicates that the stiffness of the stabilized RDS would increase upon the increment of cement content. Based on the above test results, it is concluded that the dredged soil from Brahmaputra River can be stabilized with cement for making compressed earth block which would be an alternative to the burnt clay brick that uses valued agricultural soil as raw material. Progressive Agriculture 32 (1): 71-77, 2021

A fogászati kerámiaanyagok fejlődésének történeti áttekintése

Initially, ceramics - mostly burnt clay - were used to manufacture container pottery. The first porcelain objects reached Europe out of China in the Medieval Ages. The technique of their manufacturing was a mystery for many hundred years, yet Germans succeeded first to produce fine European porcelain at the beginning of the 18th century. Its elegance and hardness woke the dentists’ interest too thus Frenchmen created the first porcelain dentures in the second half of the 18th century. Since then, there has been an increasing demand for esthetic fixed implant dentures instead of removable ones. The development of ceramic materials resulted in better mechanical and optical properties, thus the first fixed porcelain inlays and jacket crowns were introduced already in 1889. The addition of leucite filler crystals to porcelain in the 20th century increased the thermal expansion of the ceramic. It could be fired on common dental casting alloys, so the first porcelain-fused-to-metal (PFM) crown was created in 1962. Several new techniques were developed from the middle of the 1980s to the end of the 1990s to deal with initial shrinkage and achieve better properties. Beyond casting, pressing, and CAD/CAM technology, additive manufacturing opened new perspectives in dentistry several years ago in processing dental ceramics.