Experimental analysis of basic mechanical properties of concrete upon replacement with silica fume and steel slag

The prime aim in this paper is to find out the effect of Silica Fume and Steel Slag replacements for cement and fine aggregate respectively in the concrete matrix. The research included replacement of constant percentage of silica fume i.e. 10% with cement and varying percentages of steel slag replacements viz. 40%, 45%, 50% and 55% with fine aggregates. It was found from the experimental investigations that optimum results for strength in compression, flexure and split case for concrete were established on 10% of silica fume replacement for steel slag and 50% replacement of steel slag with sand.

URAGAN-2M GAS MIXING SYSTEM

Gas mixture system (GMS) was developed, created and installed at Uragan-2M (U-2M) device. GMS is based on already known gas mixing method  successive puffing. It is implemented through successive puffing of several gases from separate high pressure cylinders into working volume. A number of experiments were carried out to create a He+H2 gas mixture with different percentages. The results of measurements of the He+H2 percentage in the GMS and the U-2M vacuum chamber are in good agreement each to other. This system allows you to change the pressure of the mixture in the U-2M chamber at a constant percentage of gases in the mixture.

A Study on Mechanical Properties of Concrete Incorporating Aluminum Dross, Fly Ash, and Quarry Dust

The amount of waste, associated waste disposal costs, and environmental contamination may be minimized by identifying effective recycling approaches. These promising approaches will also lead to the protection of natural resources and economic gains. One example of waste disposal maybe by using it as a filling material or as a pozzolanic material for the production of concrete. In this regard, this study proposes to partially replace cement with aluminum dross and fly ash, and partially replace natural sand with quarry dust. Aluminum dross, cement, sand, and quarry dust were used in a variety of proportions with a constant percentage of fly ash for the design of nine concrete mixtures. Aluminum dross was replaced by 5, 10, 15, and 20% of the cement mass. At first, the optimum replacement of aluminum dross without using quarry dust was determined at a constant percentage of fly ash-15% based on the strength results. Later, by introducing the optimum substitution of aluminum dross with cement and fly ash, the quarry dust was partially replaced at 10, 20, 30, and 40% of river sand to determine the overall optimum mix. The mechanical and durability characteristics of the concrete using the three mixtures were analyzed. It has been observed that the mechanical and durability characteristics of a concrete mixture incorporating a fly ash-15%, aluminum dross-10%, and quarry dust-20% are better than that of standard concrete. Production of concrete using industrial waste can minimize infrastructure construction costs and reduce environmental impacts.

Control of Land Pollution by the Partial Replacement of Effluent Sludge in Manufacturing of Fly ash Bricks

This study involves the experimental investigation of effect of fly ash and dry sludge on the properties of fly ash bricks. On seeing the present day demand for bricks, an attempt is made to study the behavior of bricks manufactured using, different waste materials like dry sludge and fly ash. The main aim of this work was to compare the compressive strength of the bricks. The disposal of sludge has always been by dumping in the soil, this has hazardous effect on the air and environment at large. They can be recycled for use in construction industry without producing any harm to human and environment. Research has shown that they can be used in manufacturing of cement. Sludge and fly ash mixed with Quarry dust and cement in various percentage keeping the Quarry dust and cement with constant percentage of 30% and 20% respectively, while fly ash is replaced with sludge from 0% to 100% consequently with 20% replacement. The result shows that fly ash and sludge together can be used in the alternative bricks, the compressive strength and water absorption is good and weight of the brick is reduced up to10% from the nominal bricks.

Experimental Investigation of Al-Mg-SiC-Fly Ash Composites for Automotive Alloy Wheel Rims

The conservation of resources is the biggest concern for the past half century. The mankind is heading towards the betterment of living with a key intention to obtain pertaining results with less effort. One such field which has been an extensive outreach for research and innovation is the composite materials. This study focuses on design and development of a new composition of materials which has enhanced mechanical properties than the existing materials. This study is about combining four materials namely aluminium, magnesium, SiC and fly ash in various proportions and to test the obtained specimens. The test specimens are fabricated with aluminium as the metal matrix and other materials (Mg, SiC and fly ash) as reinforcements. Three different combinations are designed by keeping the fly ash, silicon carbide at constant percentage and varying the contents of aluminium and magnesium. The results of the tests are promising and the proposed composition can be a potential reliable replacement material for existing alloy wheels.

Study on strength and durability characteristics of polypropylene fiber reinforced blended concrete tiles

Concrete is brittle and widely used as an artificial construction material with incorporation of cement, water and aggregate in necessary proportions. To overcome the brittle behavior of composites, fibers and admixture are added to the concrete. In this present investigation Polypropylene Fiber is added in varying percentage (0.2%, 0.4%, 0, 6%, 0.8% and 1%) to the weight of cement and constant percentage of Rice Husk Ash (15%) is replaced with cement. The polypropylene fiber reinforced blended concrete tiles of size 300mm x 300mm x 30mm are cast as per the code and tested at 28 days curing period. Flexural strength, Abrasion test, Dimensional quality and water absorption are studied. Among different proportion of Polypropylene Fiber Reinforced Blended Concrete, the best performance is achieved by the combination of 15% of Rice Husk Ash with 0.6% of Polypropylene Fiber.

Valid analytical performance specifications for combined analytical bias and imprecision for the use of common reference intervals

Background Many clinical decisions are based on comparison of patient results with reference intervals. Therefore, an estimation of the analytical performance specifications for the quality that would be required to allow sharing common reference intervals is needed. The International Federation of Clinical Chemistry (IFCC) recommended a minimum of 120 reference individuals to establish reference intervals. This number implies a certain level of quality, which could then be used for defining analytical performance specifications as the maximum combination of analytical bias and imprecision required for sharing common reference intervals, the aim of this investigation. Methods Two methods were investigated for defining the maximum combination of analytical bias and imprecision that would give the same quality of common reference intervals as the IFCC recommendation. Method 1 is based on a formula for the combination of analytical bias and imprecision and Method 2 is based on the Microsoft Excel formula NORMINV including the fractional probability of reference individuals outside each limit and the Gaussian variables of mean and standard deviation. The combinations of normalized bias and imprecision are illustrated for both methods. The formulae are identical for Gaussian and log-Gaussian distributions. Results Method 2 gives the correct results with a constant percentage of 4.4% for all combinations of bias and imprecision. Conclusion The Microsoft Excel formula NORMINV is useful for the estimation of analytical performance specifications for both Gaussian and log-Gaussian distributions of reference intervals.

Analyzing Retirement Withdrawal Strategies

An optimal withdrawal strategy beginning at age 65 provides a lifetime income from a portfolio, adjusted annually for inflation, while reducing the probability of living in financial ruin to an ac-ceptable level. This paper analyzes the probability of living in financial ruin, potentially for multiple years, rather than just the event of ruin. A stochastic Excel model was developed to simulate the effect of varying investment returns on a portfolio with two asset classes; large company stocks and long-term government bonds. A stochastic model is also applied to retiree mortality. The following variables were analyzed to determine their relative impact on withdrawal strategies: • Withdrawing a constant percentage of the portfolio, • Gender, • Initial asset allocation, • Asset allocation rebalancing methods, and • Low investment return environments. For both genders and most withdrawal rates, an approximately equal initial asset allocation of stocks and bonds, combined with a level rebalancing function, provided the lowest probability of living in financial ruin. Because each investment return followed its own probability distribution function, some retirees experienced financial ruin even in the most conservative simulations.