Nitric acid attack on polypropylene. Weight and density changes and blister formation during the initial stages

1970 ◽  
Vol 14 (7) ◽  
pp. 1833-1845 ◽  
Author(s):  
V. J. Armond ◽  
J. R. Atkinson
Keyword(s):  
Nitric Acid ◽  
Acid Attack ◽  
Blister Formation

Properties of soils and clays after acid treatment. I. Clay minerals

Soil Research ◽  
1981 ◽  
Vol 19 (2) ◽  
pp. 147 ◽  
Author(s):  
NS Yeoh ◽  
JM Oades
Keyword(s):  
Nitric Acid ◽  
Phosphoric Acid ◽  
Surface Area ◽  
Acid Treatment ◽  
Silica Layer ◽  
Reaction Products ◽  
Acid Attack ◽  
Aluminium Phosphate ◽  
Water Dispersible ◽  
Acid Acid

Phosphoric acid was more efficient than nitric acid of the same molarity in dissolution of clays in a closed system. Phosphoric acid released considerably more aluminium from kaolinite than did nitric acid. Acid attack released equimolar quantities of aluminium and silicon from kaolinite, but with illite and bentonite the tetrahedral silica layer was preferentially dissolved compared with the octahedral layer. When the reaction products from acidification with phosphoric acid were precipitated in the presence of the clays, they were shown to exist as an aluminium phosphate containing 2 moles of aluminium to each mole of phosphorus and probably amorphous silica. The material existed as small (0.025 �m diameter) particles with a negative charge approaching 20Cg-1. The new materials increased the surface area of a kaolinite consisting of large particles, but decreased the surface area of an illite and montmorillonite. The material was responsible for aggregating all three clays. The results indicate that phosphoric acid treatment of soils should decrease water dispersible clay and improve aggregation of soils by supplying intersititial cements of aluminium phosphate and silica.

Effect of Calcium Dissolution on the Fracture Properties of Concrete Exposed to Nitric Acid Environment

2011 ◽  
Vol 374-377 ◽  
pp. 1974-1978
Author(s):  
Hai Long Wang ◽  
Chun Ling Guo ◽  
Xiao Yan Sun
Keyword(s):  
Fracture Toughness ◽  
Nitric Acid ◽  
Mouth Opening ◽  
Crack Mouth Opening Displacement ◽  
Unstable Fracture ◽  
Crack Mouth ◽  
Acid Attack ◽  
Opening Displacement ◽  
Fracture Properties ◽  
Initial Fracture

The effect of calcium leaching by nitric acid on fracture properties of concrete was experimentally studied. The double-K fracture parameters were investigated using three-point bending beams, and the deterioration regularity of fracture properties of concrete chronically attacked by nitric acid was gotten on basis of these results. The load-crack mouth opening displacement curves under different nitric attack periods were obtained by pasting some strain gauges onto the pre-crack tip. On basis of the double-K criterion, the unstable fracture toughness as well as the initial fracture toughness was calculated according to the critical crack mouth opening displacement, the unstable fracture load and initial cracking load which can be obtained from the test. The experimental results indicated that the ratio of the initial fracture toughness to the unstable fracture toughness varied between 0.47 and 0.61 approximately. Both of the unstable fracture toughness and the initial fracture toughness decrease with attack period especially during the early 60 days, then drop to a stable trend gradually. In addition, the initial fracture toughness is less sensitive to acid attack compared with the unstable fracture toughness.

scholarly journals The effect of pozzolanic mineral additives on the strength and durability properties of structural lightweight concrete

2021 ◽  
Vol 2 (2) ◽  
pp. 35-40
Author(s):  
Engin Yener
Keyword(s):  
Compressive Strength ◽  
Sulfuric Acid ◽  
Nitric Acid ◽  
Lightweight Concrete ◽  
Acid Resistance ◽  
High Strength ◽  
Strength Development ◽  
Acid Attack ◽  
Ductile Behavior ◽  
Sulfuric Acid Solutions

Structural lightweight concretes have the potential to be used in road pavements and bridge decks due to their properties such as sufficient wear resistance, high impermeability, superior freeze-thaw resistance and ductile behavior. However, road pavements are directly exposed to nitric acid and sulfuric acid solutions created by the exhaust gases of transportation vehicles in humid environments. Therefore, the concrete to be used in road pavements must be resistant to these acid effects. In addition, sufficient strength must be guaranteed when used as pavement material. The aim of this study is to produce lightweight concrete suitable for road pavements and other structures exposed to acid effects. For this, the effect of silica fume (SF) and fly ash (FA) on acid resistance and strength development of lightweight concrete with perlite aggregates was investigated. Five different lightweight concrete mixtures were produced by substituting 0%, 5%SF, 10% SF, 10%FA, 20% FA instead of cement by weight. Natural perlite rock has been used as an aggregate source in order to provide high strength and lightness. The cylindrical samples produced were kept in lime saturated water cure for 120 days and their compressive strength was measured on the 28th, 56th, 90th and 120th days. In addition, in order to monitor the acid resistance, the strength changes of the samples exposed to 5% sulfuric acid and 5% nitric acid solution after 28 days of standard curing were followed until the 120th day. Results show that, SF and FA additives increase the compressive strength especially at older ages. In case of 10% SF, the 120-day strength value increased by 18.6% and reached 34.5 MPa. Also, lightweight perlite concrete is highly resistant to nitric acid and sulfuric acid effects. In the case of 92 days of nitric acid and sulfuric acid exposure, the strength losses are only 5.2% and 13.4%, respectively. In order to fully benefit from SF and FA, concretes must be adequately cured before acid attack. It has been concluded that it is possible to produce high-strength and acid-resistant lightweight concretes suitable for road pavements and many other structural elements by using natural perlite aggregate.

scholarly journals DURABILITY OF FLY ASH GEOPOLYMER MORTARS IN NITRIC ACID–EFFECT OF ALKALI (NA2O) CONTENT / GEOPOLIMERINIO SKIEDINIO, PAGAMINTO NAUDOJANT LAKIUOSIUS PELENUS, ILGAAMŽIŠKUMAS AZOTO RŪGŠTYJE: ŠARMŲ (NA2O) KIEKIO POVEIKIS

2011 ◽  
Vol 17 (3) ◽  
pp. 393-399 ◽  
Author(s):  
Suresh Thokchom ◽  
Partha Ghosh ◽  
Somnath Ghosh
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Nitric Acid ◽  
Acid Solution ◽  
Nitric Acid Solution ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Acid Attack ◽  
Na2o Content ◽  
Visual Appearance

Durability of fly ash based geopolymer mortar specimens in Nitric acid solution was investigated on three different series of specimens manufactured by activating fly ash with a mixture of sodium hydroxide and sodium silicate solution containing Na2O ranging from 5% to 8% of fly ash. Specimens were exposed in 10% by weight Nitric acid solution up to 24 weeks. The effect of alkali (%Na2O) content on durability of geopolymer mortar specimens were studied in terms of visual appearance, change in weight and change in compressive strength. Mineralogical and microstructure changes due to nitric acid attack were also investigated. Geopolymer mortar specimens showed excellent durability in terms of extremely less weight loss as well as high retention of compressive strength. Specimens with higher alkali content exhibited better durability in nitric acid. Santrauka Buvo tiriamas geopolimerinio skiedinio bandinių, pagamintu naudojant lakiuosius pelenus, ilgaamžiškumas azoto rūgšties tirpale. Buvo tiriami trijų skirtingų partijų bandiniai, pagaminti pridėjus lakiųjų pelenų, kurie turi natrio hidroksido ir natrio silikato mišinį, jo sudėtyje Na2O svyruoja 5–8% nuo lakiųjų pelenų kiekio. Bandiniai 24 savaites buvo veikiami 10% (pagal masę) azoto rūgšties tirpalu. Šarmų (% Na2O) kiekio poveikis geopolimerinio skiedinio bandinių ilgaamžiškumui buvo tiriamas įvertinant išvaizdą, nustatant masės ir gniuždomojo stiprio pokytį. Taip pat buvo nustatyti mineraloginiai ir mikrostruktūriniai pokyčiai veikiant azoto rūgštimi. Geopolimerinio skiedinio bandinių ilgaamžiškumas buvo labai didelis, masės nuostoliai nedideli ir didelis gniuždomasis stipris. Bandiniai su didesniu šarmų kiekiu buvo ilgaamžiškesni azoto rūgštyje.

Ectodesmata as Revealed By Freeze-Etch Preparations of Plant Epidermal Cell Walls

1973 ◽  
Vol 31 ◽  
pp. 468-469
Author(s):  
N.C. Lyon ◽  
W. C. Mueller
Keyword(s):  
Electron Microscopy ◽  
Acetic Acid ◽  
Nitric Acid ◽  
Oxalic Acid ◽  
Light Microscopy ◽  
Epidermal Cell ◽  
Cell Walls ◽  
Plant Viruses ◽  
Plant Leaves ◽  
Thin Sections

Schumacher and Halbsguth first demonstrated ectodesmata as pores or channels in the epidermal cell walls in haustoria of Cuscuta odorata L. by light microscopy in tissues fixed in a sublimate fixative (30% ethyl alcohol, 30 ml:glacial acetic acid, 10 ml: 65% nitric acid, 1 ml: 40% formaldehyde, 5 ml: oxalic acid, 2 g: mecuric chloride to saturation 2-3 g). Other workers have published electron micrographs of structures transversing the outer epidermal cell in thin sections of plant leaves that have been interpreted as ectodesmata. Such structures are evident following treatment with Hg++ or Ag+ salts and are only rarely observed by electron microscopy. If ectodesmata exist without such treatment, and are not artefacts, they would afford natural pathways of entry for applied foliar solutions and plant viruses.

The Action of Nitric Acid on Aluminium

1916 ◽  
Vol 82 (2122supp) ◽  
pp. 150-150
Author(s):  
R. Seligman ◽  
P. Williams
Keyword(s):  
Nitric Acid
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