Mūrējumu korozija apkārtējās vides ietekmē

Būvniecībā kopš seniem laikiem izmanto neorganiskās saistvielas. Materiāli kultūrvēsturiskajos un mākslas pieminekļos pastāvīgi tiek pakļauti struktūras sairšanas procesiem, kurus paātrina arvien pieaugošais vides piesārņojums. Autotransporta dūmgāzes gaisā izdala NxOy, SO2, CO un CO2, kas saistās ar gaisa mitrumu un veido skābos lietus. Tie kopā ar putekļiem un sodrējiem nonāk uz mūrējumu virsmas, veidojot blīvu slāni. Rezultātā sākas ķīmiski korozijas procesi, veidojoties ūdenī šķīstošiem sāļiem (visbiežāk – nātrija, kālija, kalcija un magnija sulfāti). Atmosfēras mitruma svārstību un žūšanas procesu rezultātā šie sāļi kristalizējas un izraisa mūrējuma sairšanu, ko veicina bioloģiskā un fizikālā korozija.Pirmie pētījumi par mūrējumu un dabīgo akmens materiālu koroziju Latvijā sākti 1984. g. RTU Silikātu tehnoloģijas katedrā. 1995. g. RTU Silikātu materiālu institūtā tika nodibināts Akmens materiālu konservācijas un restaurācijas centrs (AMKRC). Tā darbības pamatā ir kultūrvēsturisko pieminekļu zinātniskā analīze – korodējošo materiālu sastāva, struktūras, fizikālo un mehānisko īpašību izpēte.In restoration of the masonry, it is important to maintain its original composition and appearance by matching historical materials with appropriate material which is consistent both visually and in accordance with physical and chemical properties. Materials of historic-cultural and artistic monuments are constantly exposed to disintegration processes which are accelerated by ever- increasing environmental pollution (NxOy, SO2, CO and CO2). This environmental pollution reacts with moisture from air and causes acid rain. As a result, water- soluble salts (most commonly sodium, potassium and magnesium sulphates, and gypsum) are formed, causing the chemical corrosion of the masonry, which can cause its disintegration.The earliest research on corrosion of masonry and of natural stone materials in Latvia was conducted in 1984 at the Department of Silicate Technologies, Riga Technical University. In 1995 the Center for Conservation and Restoration of Stone Materials was established at the Institute of Silicate Materials, Riga Technical University. Research by the Center includes scientific analyses of cultural-historical monuments – the study of the composition, structure, physical, and mechanical properties of corroding materials.

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Study of the Incorporation of Biomass Bottom Ash as a Filler for Discontinuous Grading Bituminous Mixtures with Bitumen Emulsion

Applied Sciences ◽

10.3390/app11083334 ◽

2021 ◽

Vol 11 (8) ◽

pp. 3334

Author(s):

Jorge Suárez-Macías ◽

Juan María Terrones-Saeta ◽

Francisco Javier Iglesias-Godino ◽

Francisco Antonio Corpas-Iglesias

Keyword(s):

Raw Materials ◽

Bottom Ash ◽

Chemical Properties ◽

Physical And Mechanical Properties ◽

Waste Biomass ◽

Bituminous Mixtures ◽

Bitumen Emulsion ◽

Main Disadvantage ◽

Physical And Chemical ◽

And Chemical Properties

Energy consumption, because of population development, is progressively increasing. For this reason, new sources of energy are being developed, such as that produced from the combustion of biomass. However, this type of renewable energy has one main disadvantage, the production of waste. Biomass bottom ash is a residue of this industry that currently has not much use. For this reason, this research evaluates its use as a filler in bituminous mixtures, since this sector also has a significant impact on the environment, as it requires large quantities of raw materials. With this objective, first, the physical and chemical properties of biomass bottom ashes were evaluated, verifying their characteristics for their use as filler. Subsequently, bituminous mixtures were conformed with biomass bottom ash as filler, and their physical and mechanical properties were analyzed through particle loss and Marshall tests. The results of these tests were compared with those obtained with the same type of mixture but with conventional and ophite aggregates. This study confirmed that biomass bottom ash was viable for use as a filler, creating mixtures with a higher percentage of bitumen, better mechanical behavior, and similar physical properties. In short, more sustainable material for roads was obtained with waste currently condemned to landfill.

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On eccentricity-based topological descriptors of water-soluble dendrimers

Zeitschrift für Naturforschung C ◽

10.1515/znc-2018-0123 ◽

2018 ◽

Vol 74 (1-2) ◽

pp. 25-33 ◽

Cited By ~ 11

Author(s):

Zahid Iqbal ◽

Muhammad Ishaq ◽

Adnan Aslam ◽

Wei Gao

Keyword(s):

Molecular Structure ◽

Chemical Properties ◽

Topological Indices ◽

Water Soluble ◽

Connectivity Index ◽

Topological Descriptors ◽

Physical And Chemical Properties ◽

Eccentric Connectivity Index ◽

Physical And Chemical ◽

And Chemical Properties

AbstractPrevious studies show that certain physical and chemical properties of chemical compounds are closely related with their molecular structure. As a theoretical basis, it provides a new way of thinking by analyzing the molecular structure of the compounds to understand their physical and chemical properties. The molecular topological indices are numerical invariants of a molecular graph and are useful to predict their bioactivity. Among these topological indices, the eccentric-connectivity index has a prominent place, because of its high degree of predictability of pharmaceutical properties. In this article, we compute the closed formulae of eccentric-connectivity–based indices and its corresponding polynomial for water-soluble perylenediimides-cored polyglycerol dendrimers. Furthermore, the edge version of eccentric-connectivity index for a new class of dendrimers is determined. The conclusions we obtained in this article illustrate the promising application prospects in the field of bioinformatics and nanomaterial engineering.

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Some Physical, Chemical and Mineralogical Properties of Some Canadian Fly Ashes

MRS Proceedings ◽

10.1557/proc-86-113 ◽

1986 ◽

Vol 86 ◽

Cited By ~ 4

Author(s):

R. C. Joshi ◽

B. K. Marsh

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Chemical Properties ◽

Water Soluble ◽

Pozzolanic Activity ◽

Unburned Carbon ◽

Magnetic Fraction ◽

Fly Ashes ◽

Physical And Chemical

ABSTRACTThis paper gives physical and chemical properties of some Canadian fly ashes. Specific surface area, magnetic fraction, water soluble fraction and fraction finer than 45 μm were determined as part of the physical tests. Thermo-gravimetric analyses (TGA) in oxygen and nitrogen were conducted on raw ash samples. The change of pH with time in suspensions of the different ashes in water was also determined. Pozzolanic activity of the ashes with lime for all the ashes was evaluated to measure ash reactivity.The ash activity seems to be related to fineness of the ash measured by the Blaine air permeability method, but not to the fineness measured by nitrogen sorption. Generally the greater the specific surface area, the higher the reactivity of the ash. The correlation was, however, not strong and no other physical or chemical parameter measured in this investigation seems to be related to pozzolanic activity.The results of pH and TGA tests indicated that the ashes differ in many respects from each other. The TGA data suggest that loss on-ignition in many of the ashes is not entirely due to the presence of unburned carbon. Specific surface area determined by various methods seems to provide different values. No characterization parameter was found that was uniquely related to coal type.

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Current Progress in Cross-Linked Peptide Self-Assemblies

International Journal of Molecular Sciences ◽

10.3390/ijms21207577 ◽

2020 ◽

Vol 21 (20) ◽

pp. 7577

Author(s):

Noriyuki Uchida ◽

Takahiro Muraoka

Keyword(s):

Self Assembly ◽

Three Dimensional ◽

Chemical Properties ◽

Water Soluble ◽

Cross Linking ◽

Physical And Chemical Properties ◽

Cell Scaffold ◽

Scaffold Materials ◽

Physical And Chemical ◽

And Chemical Properties

Peptide-based fibrous supramolecular assemblies represent an emerging class of biomaterials that can realize various bioactivities and structures. Recently, a variety of peptide fibers with attractive functions have been designed together with the discovery of many peptide-based self-assembly units. Cross-linking of the peptide fibers is a key strategy to improve the functions of these materials. The cross-linking of peptide fibers forming three-dimensional networks in a dispersion can lead to changes in physical and chemical properties. Hydrogelation is a typical change caused by cross-linking, which makes it applicable to biomaterials such as cell scaffold materials. Cross-linking methods, which have been conventionally developed using water-soluble covalent polymers, are also useful in supramolecular peptide fibers. In the case of peptide fibers, unique cross-linking strategies can be designed by taking advantage of the functions of amino acids. This review focuses on the current progress in the design of cross-linked peptide fibers and their applications.

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Report on Thermoplastic Coal Tar Base Linings—A Report of NACE Unit Committee T-6A on Organic Coatings And Linings for Resistance to Chemical Corrosion, Prepared by Task Group T-6A-16 on Coal Tar Coatings*

CORROSION ◽

10.5006/0010-9312-14.7.35 ◽

1958 ◽

Vol 14 (7) ◽

pp. 35-37 ◽

Cited By ~ 1

Keyword(s):

Sea Water ◽

Coal Tar ◽

Chemical Properties ◽

Surface Preparation ◽

Fats And Oils ◽

Organic Coatings ◽

Physical And Chemical Properties ◽

Chemical Corrosion ◽

Physical And Chemical ◽

And Chemical Properties

Abstract The relative resistances to various chemical environments are given for thermoplastic coal tar base linings. Media to which these linings are exposed include 11 acids, 5 alkalies, 2 oxidizing agents, 3 fats and oils, 5 gases, 7 solvents, 12 salts, as well as to sodium hypochlorite and to tap, distilled and sea water. Physical and chemical properties are listed for both hot and cold applied coatings. The application of coal tar base linings is considered in detail with special attention paid to such matters as coverage, surface preparation, priming, and application methods. 5.4.3

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Methods of Forecasting Wear Resistance of Cutting Tools Based on the Properties of their Materials

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.682.491 ◽

2014 ◽

Vol 682 ◽

pp. 491-494 ◽

Cited By ~ 2

Author(s):

Vladislav Bibik ◽

Elena Petrova

Keyword(s):

Tool Life ◽

Metal Cutting ◽

Cutting Tool ◽

Cutting Tools ◽

Chemical Properties ◽

Tool Material ◽

Composition Structure ◽

Metal Cutting Tool ◽

Physical And Chemical ◽

Thermo Physical Properties

The author considers methods of forecasting metal-cutting tool life based on characteristics of cutting tool material. These characteristics depend on differences in numerical values of physical and chemical properties of tool material due to changes in its composition, structure, and production process variables. The described methods allow obtaining the information necessary for forecasting the tool life beyond the process of cutting, for example at the stage of cutting tool manufacturing. The author suggests using the method of registration of thermo-physical properties of the tool material as a promising forecasting technique.

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PERUBAHAN BEBERAPA SIFAT FISIS DAN KIMIA PASTA GAMBIR SELAMA PENYIMPANAN

Jurnal Riset Kimia ◽

10.25077/jrk.v1i2.21 ◽

2015 ◽

Vol 1 (2) ◽

pp. 102

Author(s):

Anwar Kasim ◽

Yoli Sub’han ◽

Netty Sri Indeswari

Keyword(s):

Physical Properties ◽

Chemical Properties ◽

Water Soluble ◽

Soluble Substance ◽

Initial Water ◽

Randomized Design ◽

Chemical Content ◽

Water Soluble Substance ◽

Physical And Chemical ◽

Storage Change

ABSTRACT Studying about the change of physical and chemical properties Gambir paste during 28 days was conducted in order to know the change primarily the chemical content and physical properties as storage consequences. Experimental design was used completely randomized design for 4, 8, 12, 16, 20, 24, and 28 days storage periods. Replication was two and as a control was used paste non treatment. F-test and T-Dunnet test were applicated for statistical analysis. The result indicated that treatment can not change physical properties but change the chemical properties gambir paste. The initial water contents of gambir paste was 72.26% and after 28 days storage 71.68%. Color of gambir paste was still yellow during storage. The initial non water soluble substance was 6.96% and after 28 days storage 4.69%. The initial non alcohol soluble substance was 14.83% and after 28 days storage 13.15%. The initial chatechin contents was 72.22% and after 28 days storage 65.38%. The initial tannin contents 38.68% and after 28 days storage 35.12%. Total ash content of gambir paste was 2.72%. Keywords : gambir, paste, storage, change, properties

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WILDIERS' BIOS AND THE LACTIC ACID BACTERIA: THE RELATION OF BIOS TO THE WATER-SOLUBLE B-VITAMINS

Canadian Journal of Research ◽

10.1139/cjr38b-005 ◽

1938 ◽

Vol 16b (2) ◽

pp. 46-53 ◽

Cited By ~ 3

Author(s):

Blythe Alfred Eagles ◽

Olga Okulitch ◽

Arthur Stephen Kadzielawa

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Chemical Properties ◽

Water Soluble ◽

Vitamin B ◽

Physical And Chemical Properties ◽

Heat Stable ◽

Physical And Chemical ◽

Growth Of Animals ◽

And Chemical Properties

The influence of three distinct activators prepared from tomatoes, yeast, or liver, on the metabolism of two species of lactic acid bacteria has been studied. One of these activators is Bios II A, and the other two have been shown to be components constituting Bios II B. On the basis of their physical and chemical properties, it is suggested that the growth stimulants required by the lactic acid bacteria are identical with certain of the heat-stable accessory food factors of the Vitamin-B complex essential for the growth of animals.

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Zero→Two-Dimensional Metal Nanostructures: An Overview on Methods of Preparation, Characterization, Properties, and Applications

Nanomaterials ◽

10.3390/nano11081895 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1895

Author(s):

Ming Yang ◽

Xiaohua Chen ◽

Zidong Wang ◽

Yuzhi Zhu ◽

Shiwei Pan ◽

...

Keyword(s):

Low Cost ◽

Chemical Properties ◽

Physical And Mechanical Properties ◽

Characteristic Size ◽

Metal Nanostructures ◽

Physical Parameters ◽

Preparation Methods ◽

Composition And Structure ◽

Application Fields ◽

Physical And Chemical

Metal nanostructured materials, with many excellent and unique physical and mechanical properties compared to macroscopic bulk materials, have been widely used in the fields of electronics, bioimaging, sensing, photonics, biomimetic biology, information, and energy storage. It is worthy of noting that most of these applications require the use of nanostructured metals with specific controlled properties, which are significantly dependent on a series of physical parameters of its characteristic size, geometry, composition, and structure. Therefore, research on low-cost preparation of metal nanostructures and controlling of their characteristic sizes and geometric shapes are the keys to their development in different application fields. The preparation methods, physical and chemical properties, and application progress of metallic nanostructures are reviewed, and the methods for characterizing metal nanostructures are summarized. Finally, the future development of metallic nanostructure materials is explored.

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Rubber Material Properties of Several Rubber Tree Strains

E3S Web of Conferences ◽

10.1051/e3sconf/201913603001 ◽

2019 ◽

Vol 136 ◽

pp. 03001

Author(s):

Wang Kaidian ◽

Han Quanhui ◽

Lu qingzhi ◽

Chen Zhanxiong ◽

Li Jianhui ◽

...

Keyword(s):

Mechanical Properties ◽

Rubber Tree ◽

Chemical Properties ◽

Physical And Mechanical Properties ◽

Physical And Chemical Properties ◽

Rubber Material ◽

Vulcanized Rubber ◽

Processing Properties ◽

Physical And Chemical ◽

And Chemical Properties

：The rubber from rubber tree strain reyan 8-79 (hainan), zhanshi 218-6 (guangdong), yunyan 73-46 and yunyan 75-11 (yunnan) were tested to determine the physical and chemical properties, processing properties of raw rubber and physical and mechanical properties of vulcanized rubber. The results showed that raw rubber from different tree strains had different physical and chemical properties, processing properties,andthe physical and mechanical properties of vulcanized rubber were different as well. Yunyan 75-11 had the highest mooney viscosity, Reyan 8-79 had the highest protein content, Zhanshi 218-6 had the best tensile and tearing strength, Yunyan 73-46 had small elastic modulus, large loss factor and good processing properties.

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