In the present study physicochemical characterization of slate sample was carried out which was collected from slate mine in Lasbela District, Baluchistan. Slate was evaluated for its effectiveness as partial replacement of ordinary Portland cement (OPC) in the production of Portland Pozzolana cement (PPC). The grain size analysis of crushed slate sample using ball mill revealed that maximum fraction retained on 44 μm was about 72.8 %. Sum of the major oxides (SiO2 + Al2O3 + Fe2O3) is about 90.09 % that meet the requirement as per ASTM C 618 (minimum 70.0 %). Other oxides including SO3 (<0.05), CaO (4.04), MgO (1.66), K2O (0.10), Na2O (0.16), TiO2 (0.35), MnO (<0.02) and Cl (0.12) also meet the international standard of ASTM C 618 for PPC. OPC without and with using slate sample in a ratio of 5 % and 10 % with clinker was tested to measure compressive strength, physical tests and setting time. The results showed that after 5 % and 10 % replacement, insignificant effect was observed on the physical properties, setting time and compressive strength in 2-, 7- and 28-days curing. Hence, slate can be used as natural pozzolan for manufacturing PPC. It is cost effective for the production of cement as well as to sustain the resources of limestone for long time and reducing emission of CO2 in the environment. It can also be used in the sulfate rich environment, coastal areas especially for the construction of dams and bridges.
In addition to the analysis of written sources and the study of maps, another source of information on the historical visual character of towns is pictorial works, i.e., vedutas and, since the 19th century, photographs. Photographs and postcards capturing public spaces and buildings that no longer exist are essential for the purposes of historical topography. Studying and comparing these materials might contribute to reconstructing past roads and urban developments, locating buildings, and defining their visual aspects and purpose. Despite the fact that photographs are a relatively recent source, one of the pitfalls might be the dating of them.
Cílem článku je upozornit na nejistoty provázející výzkum paleolitu v Čechách, a zejména publikace z posledních let. Pro kulturní i absolutní zařazení velkých souborů předmětů, získaných výzkumy prakticky pod ornicí, scházejí nesporné morfologické, stratigrafické a jiné přírodovědné argumenty. Data vzešlá z těchto výzkumů autor porovnává s výsledky z precizně zkoumaných evropských lokalit. Současně shrnuje aktuální stav bádání o starém paleolitu v Evropě a do jeho kontextu řadí nejstarší doklady přítomnosti člověka z Čech a Moravy. and The aim of the article is to point out the uncertainty accompanying studies of the Palaeolithic period in Bohemia, particularly in recent publications. Indisputable morphological, stratigraphic and other natural science arguments are lacking for cultural and absolute classification of larger assemblages of finds obtained by terrain excavation. The author of the article compares the data resulting from these excavations with meticulously investigated European sites. At the same time, the author also summarises the current state of research into Early Palaeolithic Europe and classifies the oldest evidence of man in Bohemia and Moravia into its context.
The Principality of Liechtenstein is often referred to in contemporary journalism as an "economic miracle". It is also sometimes said that Liechtenstein experienced "three golden decades" between the early 1940s and the early 1970s. Of course, the country's economic development also brings with it certain negative phenomena, such as environmental damage, the breakdown of traditional values, high land prices, and dependence on labour from abroad. Nevertheless, the country's economic boom is a remarkable fact worthy of attention, inter alia also in the context of economic history. In 1930, gross domestic product per capita in Liechtenstein was 30 percent lower than in Switzerland; there was major economic growth from the 1960s, and by 2000 it was 30 percent higher than in Switzerland. Liechtenstein's economic growth brought about a great need for manpower, which is why many employees began to come to the country from abroad, especially from its neighbouring countries. At this time, Liechtenstein companies also began to expand beyond the borders of Liechtenstein. As of 2018, a total of 10,411 employees of companies belonging to the Liechtenstein Chamber of Industry and Commerce are reported as working directly in the country, with 58,072 employees working for Liechtenstein companies operating abroad. As for employees in the banking sector, which also experienced unprecedented growth, there were a total of 2,064 in Liechtenstein as of the year in question, and 3,800 people worked for Liechtenstein banks abroad. An important indicator of economic prosperity is the tax burden. The tax quota, i.e. state and municipal revenues and revenues from social security and health insurance premiums in relation to gross domestic product, accounted for only 19.6% in Liechtenstein in 2017. For comparison, in the USA it was 27.1% and in France 46.2% The net worth of the Principality of Liechtenstein in 2017 amounted to CHF 1,613 million at the municipal level (annual expenditure 5.9) and CHF 2,652 million at the state level (annual expenditure 3.4). Public finances have recovered even from the last financial crisis thanks to the economic programmes of 2012–2016, which is why Liechtenstein continues to maintain the highest possible financial rating.