Wyniki wyszukiwania - BazTech

1

Effect of Potable, Acidic and Alkaline Water Curing on Flexure Strength of Strengthened and Unstrengthen Reinforced Concrete Beams

Barkale Akshay D., Thakare Sunil B.

Ecological Engineering & Environmental Technology

|

2023

|

Vol. 24, iss. 2

153--161

EN

The rapid growing population has resulted into the need of additional capacities of existing infrastructure facilities, commercial buildings etc. Also, the revisions of codal provisions has made many existing structures fall out of the safety criteria mandated by these provisions. In such scenario, from environmental point of view it is always better to strengthen the existing structure than demolish it and cause pollution. Such structures are made to withstand greater load than their capacity by means of supplementary systems also known as strengthening schemes. Recently, Fiber Reinforced Polymer (FRP) is in wide use in strengthening aspect due to its various advantages. Also, Potable Water is a scarcest commodity these days. Its significance in construction industry have been vital. Concrete and water being the most utilized construction materials, this paper examines the effect of different pH water levels on flexure capacity of concrete beams with and without the strengthening system. Eighteen numbers of concrete beams with conventional reinforcement are casted with size of 500x100x100 mm3. These beams are divided into six categories so that each category has three number of beams. The beams are categorized based on the FRP application and pH value of curing solution. Three types of water is used with pH in the range of 4 to 5, pH of 7.5 and pH in the range 9 to 10. Single layer of Glass Fiber Reinforced Polymer (GFRP) fabric sheet is used for flexure strength enhancement. All beams are tested using flexural test till failure. Salient points viz. load and deflection at which first crack, service and failure. These points are noted for each beam and average of three beams of a group is presented as final reading. Suitable conclusions are drawn from these test results.

2

Rare calciphilous diatoms from the genus Gomphonema (Bacillariophyta) in lotic waters of SE Poland

Noga T., Poradowska A., Peszek Ł., Rybak M.

Oceanological and Hydrobiological Studies

|

2018

|

Vol. 47, No. 1

27--40

EN

The aim of this work was to present a morphological description and ecological characteristics of a rare species from the Gomphonema genus, occurring in calcium-rich waters, along with its new occurrence sites. The research was carried out in flowing waters of mountain and sub-mountain streams and rivers in Poland: the Wołosaty, the Wisłoka, the San and their tributaries. The occurrence of many rare and new to Polish flora species from the genus Gomphonema was recorded: G. cuneolus E. Reichardt, G. drutelingense E. Reichardt, G. innocens E. Reichardt,G. lateripunctatum E. Reichardt & Lange-Bertalot, G. lippertii E. Reichardt & Lange-Bertalot and G. calcifugum Lange-Bertalot & E. Reichardt. These species occur mostly in alkaline or close-to-neutral waters with medium or low electrolytic conductivity (78–530 μS cm-1), low nutrient content and medium-to-high calcium ion content (12.4–76.4 mg l-1). Despite the rare occurrence in other parts of the world, the studied Gomphonema species has found favorable conditions in unpolluted and calcium-rich stream beds with flysch strata. The literature data define G. calcifugum as a non-calciphilous species, but this study shows that it can develop in a wide pH range and in calcium-rich waters.

3

On counter measure of vibration for machine using alkaline water with polymer

De Sousa Gama V., Tanabe I., Takahashi S.

Journal of Machine Engineering

|

2014

|

Vol. 14, No. 3

58--70

EN

In the 21st century, as it is important to produce the products with high accuracy, high quality and eco-friendly, the most of manufacturers need several daring plans, unique ideas and new technologies. For example, in machine tool technology, restraint of vibration on the machine tool was required for high accuracy and quality, and several countermeasures using costly equipment and large quantity of electrical energy were used for the restraint, however those countermeasures are not enough. Therefore a countermeasure of vibration for machine tool using alkaline water with polymer was developed and evaluated. Polyethylene oxide was used for the polymer because of the low cost and the safety for health. Relationship between the mixed polymer in the alkaline water and the damping ratio were firstly investigated. And the optimum percentage of the polymer was decided for restraint of vibration on a machine tool. Then the damper structures using alkaline water with polymer were development, and the three dampers were set for restraint of vibration in the small machine tool; those are the support units, the vise and the head stock. Each damper was evaluated regarding noise and vibration on the machine tool and surface roughness on a work piece in the experiment. It is concluded from the results that; (1) the optimum percentage of the polymer for the damper was 6 wt%, (2) the damper structures using alkaline water with polymer were very effective for restraint of both noise and vibration on the machine tool and smoothly surface on the work piece.