scholarly journals The significance of grain morphology and moisture content on the response of silica sand to ballistic penetration

2019 ◽  
Vol 115 (8) ◽  
pp. 084102
Author(s):  
J. I. Perry ◽  
C. H. Braithwaite ◽  
N. E. Taylor ◽  
A. P. Jardine
Keyword(s):  
Moisture Content ◽  
Grain Morphology ◽  
Silica Sand ◽  
Ballistic Penetration

scholarly journals Investigation of the Influence of Moisture Content on Fatigue Behaviour of HPC by Using DMA and XRCT

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 91
Author(s):  
Martin Markert ◽  
Josef Katzmann ◽  
Veit Birtel ◽  
Harald Garrecht ◽  
Holger Steeb
Keyword(s):  
Moisture Content ◽  
High Performance Concrete ◽  
Silica Sand ◽  
Loading Frequency ◽  
Strain Development ◽  
Damage Development ◽  
Moisture Contents ◽  
Moisture Influence ◽  
Number Of Cycles ◽  
Cycles To Failure

High-performance concrete (HPC) is a topic of current research and construction projects, due to its outstanding compressive strength and durability. In particular, its behaviour under high-cycle fatigue loading is the focus of current investigations, to further pave the way to highly challenging long-lasting constructions; e.g., bridges or offshore buildings. In order to investigate the behaviour of HPC with different moisture contents in more detail, a mixture of silica sand and basalt aggregate with a maximum grain size of 8 mm was investigated with three different moisture contents. For this purpose, cyclic compressive fatigue tests at a loading frequency of 10 Hz and different maximum stress levels were performed. The main focus was the moisture influence on the number of cycles to failure and the development of concrete temperature and strain. In a further step, only the mortar matrix was investigated. For this purpose, the mixture was produced without basalt, and the moisture influence was investigated on smaller-sized test specimens using dynamic mechanical analysis (DMA) and X-ray computed tomography (XRCT). It was shown that the moisture content of HPC had a significant influence on the fatigue damage behaviour due to the number of cycles to failure decreasing significantly with increased moisture. In addition, there was also an influence on the temperature development, as well as on the strain development. It was shown that increasing moisture content was associated with an increase in strain development. XRCT scans, in the course of the damage phases, showed an increase in internal cracks, and made their size visible. With the help of DMA as a new research method in the field of concrete research, we were also able to measure damage development related to a decrease in sample stiffness. Both methods, XRCT and DMA, can be listed as nondestructive methods, and thus can complement the known destructive test methods, such as light microscopy.

Experimental analysis on effect of infrared light source for moisture content test of silica sand

2020 ◽  
Author(s):  
L.D. Vijay Anand ◽  
S. Shalini Packiam Kamala ◽  
D. Hepsiba ◽  
D. Ravikumar ◽  
A. Jayapradha ◽  
...  
Keyword(s):  
Moisture Content ◽  
Light Source ◽  
Experimental Analysis ◽  
Silica Sand ◽  
Infrared Light

scholarly journals Structure and properties of fine concretes based on composite binders

Vestnik MGSU ◽  
2019 ◽  
pp. 322-331 ◽  
Author(s):  
Aleksey I. Kharchenko ◽  
Vyacheslav A. Alekseev ◽  
Igor’ Ya. Kharchenko ◽  
Dmitriy A. Bazhenov
Keyword(s):  
Moisture Content ◽  
Portland Cement ◽  
Porous Structure ◽  
Crack Resistance ◽  
Chemical Activation ◽  
Silica Sand ◽  
Structure And Properties ◽  
Strength Performance ◽  
Technical Properties ◽  
Performance Results

Introduction. Wide introduction of fine concretes in the practice of monolithic building construction is limited by their low crack resistance due to considerable shrinkage. To reduce the shrinkage adverse effect on structure and properties of the fine concretes, it is suggested to use for their preparation composite binders, including expanding sulphoaluminate-based cements. Using the fine concrete with enhanced physical and technical properties improves produceability of construction, reduces labor input of concrete casting and allows building installations of complicated architectural forms. Material and methods. To study processes of fine concrete structure formation and properties, concrete mixes were prepared on the base of medium silica sand, dispersed ash entrainment and expanding additive. Activity of the ash entrainment increased at the expense of mechanical and chemical activation. Dispersity of the particles was monitored by means of laser granulometry. The composite binder was prepared by means of thorough homogenization of the basic CEM 42.5 Portland cement and different sorts of mineral aggregates, including an expanding additive based on calcium sulphoaluminate. Maturing conditions at a certain moisture content were simulated for every composition with subsequent evaluation of concrete performance. Results. Results of the study include effect of different mineral additives distinguishing in mineral composition, dispersivity and degree of hydraulic activity on shrinkage amount and kinetics, fine concrete porous structure parameters and strength. It is understood that amount of expansion has an effect on porous structure characteristics of the fine concrete and its strength performance. The study assessed an influence of maturing conditions on the various-composition fine concrete. A considerable influence of maintaining optimal moisture content during hydration on fine concrete technical properties is committed. Conclusions. It is understood that introduction of up to 10 % of expanding sulphoaluminate-based component in basic Portland cement allows to obtain fine concrete with enhanced crack resistance, impenetrability and longevity.

Analysis of the Sand Drying Process in the Biomass-Energized Rotary Drying Machine

2021 ◽  
Vol 58 (S) ◽  
pp. 93-100
Author(s):  
Herry Susanto ◽  
Roy Hendroko Setyobudi ◽  
Danny Faturachman ◽  
Erkata Yandri ◽  
Asep Hendiarko Priyatna ◽  
...  
Keyword(s):  
Moisture Content ◽  
Building Materials ◽  
Control Method ◽  
Performance Testing ◽  
Parameter Analysis ◽  
Silica Sand ◽  
Calculation Results ◽  
And Performance ◽  
Drying Efficiency ◽  
Rotary Drying

Hebel brick (also known as a lightweight brick) is a product of modern building materials because it has a lighter weight but it is stronger than cement bricks and red bricks. Hebel bricks can withstand pressures of more than 4 MPa and are suitable as building wall materials, and speed up construction, and save on cement material costs. One of the most important materials is silica sand in the manufacture of Hebel bricks. The silica sand used in the manufacture of Hebel bricks must have a moisture content of 10 % to 15 %. The purpose of this study is to provide a solution in the form of a drying technique design using a rotational speed control method and a machine that uses biomass-based energy sources. This rotary drying machine is designed to be able to dry wet silica sand into silica sand with water content according to standards. The development of this drying machine begins with making an initial design and parameter analysis. Then proceed to the design, manufacture, and performance testing. The calculation results show that the wet base moisture content has decreased from 33.17 % to 16.58 %, the dry base moisture content decreased from 49.63 % to 19.88 % and drying efficiency also decreased from 63.11 % to 17.11 %. Hence it can be seen that the percentage of wet base moisture content reduced by 50 %, the percentage of dry base moisture content reduced by 59.94 %, and the percentage of drying efficiency reduced by 72.9 %.

scholarly journals Effect of green sand mixture with dextrin additives on mechanical properties of aluminum 6351

2021 ◽  
Vol 6 (2) ◽  
pp. 131-141
Author(s):  
Kingsley Okechukwu Ikebudu ◽  
Swift Kenneth Onyegirim ◽  
Philip Ifchukwu Udeorah
Keyword(s):  
Moisture Content ◽  
Research Work ◽  
Bentonite Clay ◽  
Organic Additive ◽  
Silica Sand ◽  
Green Sand ◽  
Molding Sand ◽  
Sand Mixture ◽  
Custom Design ◽  
Response Output

Quality of cast produced from green sand mold is been influenced by mold properties which includes green compression strength, permeability, etc. In this work the green sand used for casting of aluminum 6351 alloy specimens were made by mixing in varied percentage proportions; bentonite clay, dextrin additive and moisture content with local silica sand considering the need for most effective proportions of these mixtures to enhance green sand production of aluminum 6351 alloy products. A 3 factor, 3 level (33) design of experiment (DOE) was made for this research work using Optimal (custom) design of Design-Expert 10 software which gave 20 runs. Cylindrical specimens for green sand test were prepared according to standard per run. This was in order to study effects of bentonite clay, dextrin additive and moisture content of the green molding sand used for casting per mold this aluminum 6351 alloy. Prepared sand specimens were individually subjected to basic sand test like green sand strength and permeability test and also cast specimens per mold achieved were subjected to mechanical property test to achieve results which become the Response output of the study. These experimental results were optimized for the purpose of achieving most effective proportions of the mixtures to give effective results and from the optimal validation values, 5% water content, 12% bentonite and 8.85182% dextrin organic additive was found to be the optimized solution that gave the most effective hardness at (40.4GSS and 112PN) while 3% water, 12% bentonite clay and 9% dextrin additive gave most effective toughness at (41.9GSS and 96.10PN).

Silicon Tetrachloride Synthesis from Rice Hulls: Transmission and Scanning Electron Microscope Study

1972 ◽  
Vol 30 ◽  
pp. 236-237 ◽  
Author(s):  
Richard S. Thomas ◽  
Prabir K. Basu ◽  
Francis T. Jones
Keyword(s):  
Silicon Tetrachloride ◽  
Silica Sand ◽  
Mineral Matter ◽  
Chemical Heterogeneity ◽  
Scanning Electron Microscope Study ◽  
Rice Hulls ◽  
Hull Structure ◽  
Lower Temperature ◽  
Image Position ◽  
Disposal Problem

Silicon tetrachloride, used in industry for the production of highest purity silicon and silica, is customarily manufactured from silica-sand and charcoal.SiCl4 can also be made from rice hulls, which contain up to 20 percent silica and only traces of other mineral matter. Hulls, after carbonization, actually prove superior as a starting material since they react at lower temperature. This use of rice hulls may offer a new, profitable solution for a rice mill byproduct disposal problem.In studies of the reaction kinetics with carbonized hulls, conversion of SiO2 to SiCl4 was found to proceed within a few minutes to a constant, limited yield which depended reproducibly on the ambient temperature of the reactor. See Fig. 1. This suggested that physical or chemical heterogeneity of the silica in the hull structure might be involved.

Preparation and Standardization of a Stable AHF Plasma

1968 ◽  
Vol 19 (03/04) ◽  
pp. 423-429 ◽  
Author(s):  
G. M Thelin ◽  
Keyword(s):  
Moisture Content ◽  
Primary Standard ◽  
Healthy Male ◽  
Healthy Donors ◽  
Fresh Plasma

SummaryA stable, lyophilized AHF reference plasma has been prepared from pooled plasma from at least 50 normal healthy donors and standardized against a primary standard of fresh plasma from 20 healthy male donors aged 20 to 40. Average AHF potency of a typical lot is 98.8%, and moisture content is less than 0.5%. Under storage at -25° C, this AHF reference plasma is stable for at least 18 months. It has been used in several major coagulation laboratories, and has given consistently satisfactory and reproducible results in AHF assays.

Improvement in the Fock test for determining the reactivity of dissolving pulp

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 21-26 ◽  
Author(s):  
CHAO TIAN ◽  
LINQIANG ZHENG ◽  
QINGXIAN MIAO ◽  
CHRIS NASH ◽  
CHUNYU CAO ◽  
...  
Keyword(s):  
Moisture Content ◽  
Sodium Hydroxide ◽  
Constant Temperature ◽  
Carbon Disulfide ◽  
Testing Procedure ◽  
Dissolving Pulp ◽  
Water Bath ◽  
Testing Conditions ◽  
Pulp Sample ◽  
Fock Reactivity

The Fock test is widely used for assessing the reactivity of dissolving pulp. The objective of this study was to modify the method to improve the repeatability of the test. Various parameters that affect the repeatability of the Fock test were investigated. The results showed that Fock reactivity is dependent on testing conditions affecting the xanthation between cellulose and carbon disulfide, such as the moisture content of the pulp sample, sodium hydroxide (NaOH) concentration, xanthation temperature, carbon disulfide dosage, and xanthation time. The repeatability of the test was significantly improved using the following modified testing procedure: air dried sample in the constant temperature/humidity room, xanthation temperature of 66°F (19°C) in a water bath, xanthation time of 3 h, NaOH concentration of 9% (w/w), and 1.3 mL carbon disulfide.

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