Analysis of Alkali Oxides Influence on the Microstructure of Refractory Grog

The development and subsequent production of these special kind of grog from raw materials available in the Czech Republic is one of the possibilities how to reduce income costs for the production of refractory materials with specific properties. The experimental work is focused on verifying the possibility of producing grog with increased alumina content from available raw materials. The raw materials are kaolins and claystones. To achieve a higher content of alumina in the grog, waste mullite dust is used. In order to improve the physical and mechanical properties of the grog, modifiers are used. Selected modifiers are expected to affect positively on the resulting density while maintaining the heat properties.

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Testing and Optimization of Production of Technical Foam for the Production of Cement Foam

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.276.254 ◽

2018 ◽

Vol 276 ◽

pp. 254-258

Author(s):

Karel Mikulica ◽

Dušan Dolák

Keyword(s):

Mechanical Properties ◽

Czech Republic ◽

Construction Industry ◽

Building Materials ◽

Cement Mortar ◽

Physical And Mechanical Properties ◽

Foam Concrete ◽

The Czech Republic ◽

Insulation Materials ◽

The Many

In the current construction industry, great importance is given to the usage of thermally insulating building materials. One of the many such materials can be a cement foam or foam concrete, a mixture of cement mortar and technical foam. This material can be, due to its consistency right after mixing, applied to uneven horizontal surfaces where usage of conventional thermal board insulation materials would be complicated. This paper discusses the methodology of testing of the physical and mechanical properties of foaming additives such as strength, density, foaming number and half-separability of technical foams. Then this methodology was subsequently verified on the five commonly used foaming additives in the Czech Republic.

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Physical and mechanical properties of subfossil oak (Quercus, sp.) wood

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun201058040123 ◽

2010 ◽

Vol 58 (4) ◽

pp. 123-134 ◽

Cited By ~ 3

Author(s):

Tomáš Kolář ◽

Michal Rybníček

Keyword(s):

Mechanical Properties ◽

Czech Republic ◽

Radiocarbon Dating ◽

Physical And Mechanical Properties ◽

Wood Properties ◽

The Other ◽

The Czech Republic ◽

Oak Wood ◽

Gravel Pit ◽

Subfossil Wood

The paper deals with the examination of physical and mechanical properties of subfossil wood of oak (Quercus, sp.). The issue of establishing physical and mechanical properties of subfossil oak wood has not yet been addressed in the area of the Czech Republic. The main objective is to find out what changes to subfossil wood properties have occurred in comparison with recent wood. For these purposes, samples from three locations were taken (gravel pit Tovačov – district Přerov, gravel pit Kostomlátky – district Nymburk, and the Bečva basin near Osek nad Bečvou). All of the selected properties were tested in compliance with relevant valid Czech technical norms (ČSN). The results provide us with a realistic picture of the properties of wood that has been deposited under the ground in very specific conditions for thousands of years. With regard to density, the results do not show any definite changes. The dimensions of subfossil wood are approximately doubled in comparison with recent wood. On the other hand, there is an obvious decrease in mechanical properties. The paper also offers the results of dendrochronological or radiocarbon dating of the trunks.

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The effect of growth conditions in specific areas of Croatia and the Czech Republic on the physical and mechanical properties of black alder wood (Alnus glutinosa Gaertn.)

TURKISH JOURNAL OF AGRICULTURE AND FORESTRY ◽

10.3906/tar-1407-40 ◽

2016 ◽

Vol 40 ◽

pp. 7-12

Author(s):

Jaromír MILCH ◽

Hanuš VAVRCİK ◽

Jan TIPPNER ◽

Martin BRABEC

Keyword(s):

Mechanical Properties ◽

Czech Republic ◽

Physical And Mechanical Properties ◽

Alnus Glutinosa ◽

Growth Conditions ◽

The Czech Republic ◽

Black Alder

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KUALITAS PAPAN PARTIKEL BERDASARKAN KOMPOSISI SEKAM PADI DAN KAYU SENGON DENGAN VARIASI KADAR PEREKAT

JURNAL HUTAN LESTARI ◽

10.26418/jhl.v7i2.33693 ◽

2019 ◽

Vol 7 (2) ◽

Author(s):

Dendi Prayoga ◽

. Dirhamsyah ◽

. Nurhaida

Keyword(s):

Mechanical Properties ◽

Moisture Content ◽

Rice Husk ◽

Raw Materials ◽

Urea Formaldehyde ◽

Physical And Mechanical Properties ◽

Solid Content ◽

Particle Board ◽

Rice Husks ◽

Wood Processing

This research aimed to examine the physical and mechanical properties of particle boards based on the composition of raw materials and adhesive content and know the treatment of the composition of raw materials and the best adhesive content and meet the standard JIS A 5908-2003. The research was conducted at Wood Workshop Laboratory, Wood Processing Laboratory Faculty of Forestry,Tanjungpura University and Laboratory of PT. Duta Pertiwi Nusantara Pontianak. The adhesive used is Urea Formaldehyde with 52% Solid Content. Comparison of the composition of rice husks and sengon varies namely rice husk 50%: sengon 50%, rice husk 60%: sengon 40% and rice husk 70%: sengon 30% and variations in the levels of UF adhesives, namely 14% and 16%, with target density 0,7 gr/cm3. The particleboard was 30 cm x 30 cm x 1 cm Pressing at temperature 140oC for 8 minutes, with pressure of 25 kg/cm2. The research results of the study of density and moisture content meet the standards JIS A 5908-2003. The best particle values of rice husk and sengon with composition a ratio of rice husk 50%: sengon 50% , 16% adhesive content 16%, with density value of 0,7072 gr/cm3, moisture content 9,1949 %, thick development 12,3210 %, water absorption 68,8270 %, MOE 12110,7273 kg/cm2, MOR 161,0025 kg/cm2, firmness sticky 1,9320 kg/cm2, screw holding strength 62,3124 kg.Keywords : adhesive, composition, particle board, rice husk, sengon

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SIFAT FISIK DAN MEKANIK PAPAN GIPSUM DARI LIMBAH KAYU AKASIA (Acacia mangium Willd) BERDASARKAN KADAR GIPSUM DAN UKURAN SERBUK KAYU

JURNAL HUTAN LESTARI ◽

10.26418/jhl.v7i1.31800 ◽

2019 ◽

Vol 7 (1) ◽

Author(s):

Ridho Pratama ◽

M Dirhamsyah ◽

. Nurhaida

Keyword(s):

Mechanical Properties ◽

Raw Materials ◽

Acacia Mangium ◽

Physical And Mechanical Properties ◽

Powder Size ◽

Wood Powder ◽

Gypsum Board ◽

Randomized Design ◽

Gypsum Content ◽

Two Factors

This study aims to examine the physical and mechanical properties of gypsum board from Acacia mangium Willd wood waste based on gypsum content and wood powder size. This study refers to the JIS A 5417-1992 standard. This research were conducted at Wood Work Shop laboratory for the preparation of raw materials, Wood Technology laboratory Faculty of Forestry for board making and testing the physical properties of gypsum boards, and PT. Duta Pertiwi Nusantara laboratory to test the mechanical properties of the gypsum board. The material used is A. mangium W. Wood powder, gypsum flour, water and borax. The study uses Factorial Completely Randomized Design (CRD) with two factors, namely factor A (gypsum content) which consists of gypsum content of 400%, 500% and 600% of the weight of A. mangium W. wood powder, and factors B (wood powder size) consists of 20 mesh passes 40 mesh retained and 40 mesh passes 60 mesh retained. The results showed that the density (600% gypsum content of 40 and 60 mesh retained wood powder size), moisture content, thickness swelling, MOE (600% gypsum content of 40 and 60 mesh retained wood powder size) fulfill JIS A5417-1992 standard. The best gypsum board is gypsum board with gypsum content of 600% with a wood powder size is 40 mesh.Keyword: Acacia mangium, gypsum board, gypsum content, wood powder size.

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Experiences in the Field of Radioactive Materials Seizures in the Czech Republic

11th International Conference on Environmental Remediation and Radioactive Waste Management, Parts A and B ◽

10.1115/icem2007-7175 ◽

2007 ◽

Author(s):

Karel Svoboda ◽

Josef Podlaha ◽

David Sˇi´r ◽

Josef Mudra

Keyword(s):

Czech Republic ◽

Raw Materials ◽

Nuclear Research ◽

Municipal Waste ◽

Radioactive Material ◽

Radioactive Materials ◽

Nuclear Research Institute ◽

The Czech Republic ◽

Other Information ◽

Radioactive Sources

In recent years, the amount of radioactive materials seizures (captured radioactive materials) has been rising. It was above all due to newly installed detection facilities that were able to check metallic scrap during its collection in scrap yards or on the entrance to iron-mills, checking municipal waste upon entrance to municipal disposal sites, even incineration plants, or through checking vehicles going through the borders of the Czech Republic. Most cases bore a relationship to secondary raw materials or they were connected to the application of machines and installations made from contaminated metallic materials. However, in accordance to our experience, the number of cases of seizures of materials and devices containing radioactive sources used in the public domain was lower, but not negligible, in the municipal storage yards or incineration plants. Atomic Act No. 18/1997 Coll. will apply to everybody who provides activities leading to exposure, mandatory assurance as high radiation safety as risk of the endangering of life, personal health and environment is as low as reasonably achievable in according to social and economic aspects. Hence, attention on the examination of all cases of the radioactive material seizure based on detection facilities alarm or reasonably grounds suspicion arising from the other information is important. Therefore, a service carried out by group of workers who ensure assessment of captured radioactive materials and eventual retrieval of radioactive sources from the municipal waste has come into existence in the Nuclear Research Institute Rez plc. This service has covered also transport, storage, processing and disposal of found radioactive sources. This service has arisen especially for municipal disposal sites, but later on even other companies took advantage of this service like incineration plants, the State Office for Nuclear Safety, etc. Our experience in the field of ensuring assessment of captured radioactive materials and eventual retrieval of radioactive sources will be presented in the paper.

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Effect of Alumina (Al2O3) to the Properties of Whiteware Porcelain

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1010.194 ◽

2020 ◽

Vol 1010 ◽

pp. 194-199

Author(s):

Hamdan Yahya ◽

Aspaniza Ahmad ◽

Ismail Ibrahim

Keyword(s):

Mechanical Properties ◽

Flexural Strength ◽

Water Absorption ◽

Bulk Density ◽

Physical And Mechanical Properties ◽

Porcelain Body ◽

The Other ◽

Alumina Content ◽

Crystalline Phases ◽

Mullite Phase

The effect of Al2O3 to the properties of whiteware porcelain such as water absorption, bulk density, flexural strength and crystalline phases were studied systematically. The result shows that the addition of alumina at maximum 5 wt.% in porcelain bodies increased the flexural strength of the fired bodies which can reach 55.5 MPa, 30% higher than 0.0% alumina content. However, slight decrease in the other physical and mechanical properties was observed with Al2O3 addition higher than 5 wt.%, which is believed to be due to increased corundum phase compared to mullite phase in porcelain body.

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Effects of raw materials and process parameters on the physical and mechanical properties of flat pressed WPC panels

Composites Part A Applied Science and Manufacturing ◽

10.1016/j.compositesa.2011.12.028 ◽

2012 ◽

Vol 43 (4) ◽

pp. 570-576 ◽

Cited By ~ 23

Author(s):

Jan T. Benthien ◽

Heiko Thoemen

Keyword(s):

Mechanical Properties ◽

Process Parameters ◽

Raw Materials ◽

Physical And Mechanical Properties

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Development of Fly Ash-Based Geopolymer Lightweight Bricks Using Foaming Agent - A Review

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.660.9 ◽

2015 ◽

Vol 660 ◽

pp. 9-16 ◽

Cited By ~ 3

Author(s):

Wan Mastura Wan Ibrahim ◽

Kamarudin Hussin ◽

Mohd Mustafa Al Bakri Abdullah ◽

Aeslina Abdul Kadir ◽

Mohammed Binhussain

Keyword(s):

Mechanical Properties ◽

Fly Ash ◽

Building Material ◽

Raw Materials ◽

Construction Materials ◽

Physical And Mechanical Properties ◽

Foaming Agent ◽

Positive Effects ◽

The World ◽

Great Development

Bricks are widely used as a construction and building material due to its properties. Recent years have seen a great development in new types of inorganic cementitious binders called ‘‘geopolymeric cement’’ around the world. This prompted its use in bricks, which improves the greenness of ordinary bricks. The development of fly ash-based geopolymer lightweight bricks is relatively new in the field of construction materials. This paper reviews the uses of fly ash as a raw materials and addition of foaming agent to the geopolymeric mixture to produce lightweight bricks. The effects on their physical and mechanical properties have been discussed. Most manufactured bricks with incorporation of foaming agent have shown positive effects by producing lightweight bricks, increased porosity and improved the thermal conductivities of fly ash-based geopolymer bricks. However, less of performances in number of cases in terms of mechanical properties were also demonstrated.

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