Carbonation of concrete at ambient CO2 concentration is a slow process. This makes the testing of the resistance of concrete against carbonation often too slow to be applicable for service life assessments of new structures. Raising the CO2-concentration will accelerate the test but the validity of an increase CO2 -level is debated. If not valid, the service life can be seriously underestimated. In this paper, the effects of accelerating on the carbonation process are discussed. It is shown that a change in CO2 concentration will not change the carbonation process. Since carbonation occurs instantly, a zero CO2 concentration at the carbonation front is maintained. Moreover, it has been concluded that all hydrated and unhydrated cement ultimately carbonate. This implies that the amount of carbonatable matter can be determined on the basis of the amount of calcium in the unreacted cement.

Influence of the carbon dioxide concentration on the resistance to carbonation of concrete

This work covers the effectiveness of the White tea extract as a green corrosion inhibitor and is correlated to the strength and stability bonding between the phenolic molecule and the Fe atoms in mild steel and how this interaction can be studied by altering the concentration and temperature. White tea has received considerable attention due to its capability as a corrosion inhibitor and has been extensively studied using electrochemical techniques. However, accurate and systematic functional group identification and surface modification have been missing. Our study sought to demonstrate the quantitative measurement of electrochemical impedance spectroscopy (EIS) complemented by the FTIR (Fourier transform infrared spectroscopy), Total Phenolic Test, and Raman Spectroscopy. The SEM (Scanning Electronic Microscope)/EDX (Energy-Dispersive X-Ray Spectroscopy), and AFM (Atomic Force Microscope) were used to study the surface modification. The EIS results show that the optimum inhibition efficiency was 96 % in a solution of 80 ppm at 60 °C. Acetone 70 % was used to extract White tea and gives 14.17±0.25 % phenolic compound. Spectroscopic studies show -OH, Aromatic C=C, C=O and C-O-C become major contributors in the adsorption process and are found on the surface of metals as corrosion protection. Meanwhile, the thermodynamic calculation shows the White tea was adsorbed chemically. The nearness of R2 to 1 shows the adsorption agrees with the Langmuir adsorption isotherm. Eventually, the surface modification revealed that phenol molecules are responsible to reduce the corrosion rate at 16.38×10-3 mpy. Our results are expected to provide a guideline for future research in White tea as a green corrosion inhibitor.

Keywords: Catechin, Green Corrosion Inhibitor, Chemisorption, Adsorption, Surface Modification, Langmuir Isotherm

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Development of white tea extract as green corrosion inhibitor in mild steel under 1 M hydrochloric acid solution

The effect of microbial and chemical corrosion on concrete structures operated in the conditions of chemical enterprises has been established that makes it possible to reliably predict the timing of their decommissioning in order to prevent industrial disasters. Even though the construction complies with all building codes, concrete structures eventually undergo chemical and biological corrosion.
The innovation proposed in this study implies investigating the depth and degree of damage to concrete at the microscopic level by the method of raster electron microscopy. In addition, the TPD-MS method has been suggested for determining the quantitative and qualitative state of the carbonate components of concrete and sulfur compounds.
This study has found that in concrete samples from the titanium dioxide production plant, the amount of carbon dioxide release is twice less than in control samples at t=600 °C while the level of sulfur dioxide, on the contrary, increases. This is due to the ability of thionic bacteria to accumulate sulfate acid that destroys the cementing component in concrete. The reported results confirm the impact of products of the activity of Acidithiobacillus thiooxidans microorganisms on corrosion processes in concrete.
In addition, when using the TPD-MS method, it was established in the storage room of the finished product that heating the control sample of concrete leads to a release of the significant amount of СО2 at t=580–600 °C. However, the experimental samples of concrete are almost lacking carbon compounds because the acid metabolites of microfungi interfere with its formation. Microscopic and REM studies revealed the localization of Acidithiobacillus thiooxidans and Aspergillus fumigatus in concrete.
This study has established patterns related to the mechanism that forms chemical compounds in concrete and the metabolism of microorganisms

Defining patterns in the influence exerted by the interelated biochemical corrosion on concrete building structures under the conditions of a chemical enterprise

Concrete floors are most commonly used in animal housing. However, the specific environment of livestock buildings (moisture, urine, disinfectants) has a negative effect on concrete and leads to its corrosion. The influence of chemical and physical factors on concrete is reinforced by the development of microorganisms, which quickly adapt and use concrete as a living environment.
To reduce the influence of an aggressive environment on the concrete floor, an experimental mixture of dry disinfectants was proposed.
The components of the disinfection mixture have been selected taking into account the safety for animals and humans.
The TPD-MS method was used to determine the change in the chemical composition of concrete. To study the microstructure of concrete, the method of scanning electron microscopy was used.
Microbiological studies revealed bacteria A. Thiooxidans, S. aureus, E. coli, S. enteritidis, S. Сholeraesuis, C. Perfringen and micromycetes of the genus Cladosporium, Fusariums, Aspergillus, which contribute to the development of biological corrosion of concrete in livestock buildings. The fact of the negative impact of concentrated disinfectants on the structure of concrete was also established.
As a result of the studies carried out, it was proved that a mixture of dry components for disinfection exhibits antimicrobial properties to varying degrees to the strains of field isolates of bacteria and fungi isolated in a pig-breeding farm. It was found that when using the proposed mixture of dry disinfectants in the research room of the pigsty, the relative humidity decreases by 38.5 %; ammonia content – by 46.2 %; hydrogen sulfide – by 57.8 %; microbial bodies – by 74.7 %, compared with the control room.
It has been experimentally proven that the proposed mixture of dry disinfecting components has hygroscopic and antimicrobial properties and is promising for use in livestock farms.

/pdf/development-of-a-method-of-protection-of-concrete-floors-of-4k3us8720e.pdf

Development of a method of protection of concrete floors of animal buildings from corrosion at the expense of using dry disinfectants

The scientific task to improve energy efficiency and ensure the process of vacuum regime stabilization in the operation of milking machines has been solved.
A mathematical model of the process of functioning of the servo control system of a rotary plate vacuum pump was built; the numerical modeling of its workflow was carried out.
This paper reports the results of experimental studies on the influence of the regime parameters of the rotary plate vacuum pump on the efficiency of its operation, as well as the results of experimental research on the servo control system for the rotary plate vacuum pump.
The operational process of the rotary plate vacuum pump HB-1200 for a milking machine was investigated. The influence of mode parameters (rotor speed n and vacuum pressure P) on the performance of the vacuum pump, Qa, vacuum pressure fluctuation, ΔP, and the power consumption of the vacuum pump drive, Np, has been determined.
The servo control system of the rotary plate vacuum pump was experimentally investigated based on the developed algorithms of its operation. In a generally accepted algorithm, vacuum fluctuation increases with increasing an airflow rate: at ΔQa=45 l/min – ΔP=2.3 kPa; at ΔQa=90 l/min – ΔP=4.6 kPa; at ΔQa=135 l/min – ΔP=6.4 kPa. Unlike the generally accepted one, the developed algorithm enables a stable vacuum mode with the largest vacuum fluctuation being ΔP=2.4 kPa.
For the first time, the functional dependence of the influence of the regime parameters of the rotary plate vacuum pump with its automatic servo control system on the stability of the vacuum regime of a milk-vacuum system in the milking machine was established.
The results can be applied when improving milking machines in terms of ensuring the stabilization process of the vacuum regime.

http://journals.uran.ua/eejet/article/download/262215/259938

Justifying parameters for the automatic servo control system of a rotary plate vacuum pump in the milking machine

/pdf/pathogens-transmission-and-cytological-composition-of-cow-s-tqch9cr9kl.pdf

Pathogens Transmission and Cytological Composition of Cow’s Milk

The results of studies to determine the effect of titanium dioxide nanoparticles (nanoTiO 2 ), finely dispersed anatase crystalline titanium dioxide (anatazTiO 2 ) and surface-active substances (surfactants) on the compressive strength, degree of permeability and thermal stability of concrete samples are presented. Adding particles of nanotitanium, anatase titanium and surfactants up to 2 % to cement accelerates the hydration process and increases the strength of concrete, and also has a strong effect on its microstructure. As a result of the studies, it is experimentally proved that the compressive strength of concrete increases with the addition of titanium dioxide (nanoTiO 2 ) nanoparticles by 23.2 %, finely dispersed anatase crystalline titanium dioxide (anatazTiO 2 ) by 21.7 % to 5 % concentration by weight. In addition, the introduction of these additives reduces the permeability of concrete. This is due to a decrease in the absorption of concrete by water with the addition of nanotitanium and anatase titanium. The introduction of additives from 1 % to 5 % by weight in concrete reduces the depth of chloride penetration by 10–15 times, compared with the control. The use of temperature-programmed desorption mass spectrometry (TPD-MS) method has shown that an increase in the percentage of TiO 2 nanoparticles to 5 % in concrete mixtures correlates with an increase in microporosity and dispersion level of these mixtures, which causes a shift in the peaks of intense gas evolution from the samples when heated to the side low temperatures (for example, carbon dioxide CO 2 ). The resulting concrete samples are planned to be used for the manufacture of floors in livestock buildings. The injected additives are selected because they are not toxic substances and, in contact with the biological environment of livestock buildings (urine, feces), will not react with them

http://journal.eu-jr.eu/engineering/article/download/1178/1152/

Influence of Fine Additives and Surfactants on the Strength and Permeability Degree of Concrete

The object of this study is the regularity of changes in the biogenic destructive effect of microorganisms on the concrete structural elements of livestock facilities due to the use of the original liquid phase mixture of disinfectant based on aldehyde and surfactant.
Microorganisms use construction materials as a substrate for growth and nutrition; they produce citric acid, which leads to a change in the composition and morphology of hydrated cement new formations.
The composition of the microflora of the pigsty has been determined, and the minimum concentration of disinfectant based on glutaraldehyde and didecyl dimethyl ammonium chloride was found. By the TPD MS method, a decrease in the intensity of carbon dioxide (CO2) release in concrete samples during the heating of the sample to 900 °C was proved, compared to the control intact corrosion sample. Electron microscopy of concrete samples shows the presence of destructive changes and colonies of micromycetes. It was established that calcite was intensively released in the control sample of concrete, which retained its integrity and was not subjected to corrosion when heated to a temperature of 600 °C. Electron microscopy confirms the preservation of the homogeneous structure of concrete.
The use of a disinfectant based on glutaraldehyde and didecyl dimethyl ammonium chloride at a concentration of 1 % destroys colonies of micromycetes, 2 % – the shell of microorganisms, and 3 % – biofilm. Treatment of concrete with a disinfectant at a concentration of 3 % destroys microorganisms Aspergillus fumigatus and Penicillium oxalicum, inhibits the process of biological corrosion of concrete, and strengthens the structure of concrete.
The results of the experiment can be applied to inhibit the corrosion of concrete and extend the life of building structures made of concrete through the use of a disinfectant based on aldehyde and didecyl dimethyl ammonium chloride at a concentration of 3 %.

https://zenodo.org/record/7075138/files/Reducing%20the%20biogenic%20corrosion%20of%20concrete%20in%20a%20pigsty%20by%20using%20disinfectants.pdf

Reducing the biogenic corrosion of concrete in a pigsty by using disinfectants

t. A large number of dairy cows in Ukrainian farms suffer from subclinical 
mastitis, which leads to significant economic losses in agriculture. Conditioned 
upon the lack of clinical manifestations it is difficult to detect, in particular, 
explained by insufficient information about the microbial composition of milk. 
The ban on the use of antibiotics for productive animals is forcing new safe and 
effective remedies. The aim of the study was to determine the therapeutic effect 
of Bacillus megaterium NCH 55 in subclinical mastitis of Holstein cows. Research 
materials – milk of cows with subclinical mastitis, isolates of microorganisms and
B. megaterium NCH 55. Methods used: California test for mastitis; microscopic test 
to count the total number of somatic cells by the method of Prescott and Britt; 
bacterial method for the study of microorganisms; polymerase chain reaction 
to determine Mycoplasma spp. in milk; spectrophotometry; method VI Brillis to 
determine the adhesive properties of Bacillus megaterium NCH 55; determination 
of antagonistic properties of B. megaterium by diffusion into agar wells; the 
method of flow cytometry using the device “SomaCount Flow Cytometer”; 
physiological. The experiment was conducted in dairy farms of the North-Eastern 
region of Ukraine: LLC agrofirm “Lan”, LLC agrofirm “Vorozhbalatinvest”,
LLC agrofirm “Vladana” in the period February-August 2021. Isolates of S. aureus,
S. agalactiae, E. coli enterohemorrhagic, E. coli, Candida, E. fecalis, S. epidermidis and 
Mycoplasma spp. were detected in milk samples from cows with subclinical mastitis. 
Microscopic studies have shown that Bacillus megaterium NCH 55 are white 
gram-positive rods that have low adhesive properties and form spores. The 
greatest antagonism of B. megaterium is shown in relation to bacterial isolates 
in concentration of 1×109
, CFU/g. In 70% of cows that reached a productivity
of more than 30 kg/day on the 30th day of research, milk parameters such as the 
number of somatic cells (CSC ≤400 thousand/cm3
) and the number of mesophilic 
aerobic and facultative anaerobic microorganisms (kMAFANM) (≤100 thousand 
CFU/cm3
) corresponded to the class “Extra”. The recovery time of animals with 
subclinical mastitis depended on the degree of damage to the breast and 
individual characteristics of the organism. Cows that did not reach a productivity 
of 30 kg/day continued treatment individually. The number of somatic cells in 
the milk of cows was ≤500 thousand/cm3
 and kMAFAnM ≤200 thousand CF/cm3

Treatment of Subclinical Mastitis of Cows with Probiotics

Long-term operation of reinforced concrete structures in the conditions of chemical enterprises has a powerful negative impact on the physical and chemical properties of concrete, which leads to its destruction. The aim of this research is to determine the effect of biological and chemical corrosion on concrete structures in the workshop for the production of titanium dioxide by the sulphate method and the storage of finished products. In particular, chemical production for the synthesis of titanium dioxide by the sulfate method causes the rapid course of chemical (acid and sulfate) and microbiological (thionic bacteria and microscopic fungi) corrosion processes. These corrosion processes reinforce each other according to a synergistic principle. As a result, temperature-programmed desorption mass spectrometry (TPD MS) and scanning electron microscopy have experimentally proven the presence and spatial localization of colonies of thionic bacteria and microscopic fungi in concrete structures. Correlations between the intensity of biochemical corrosion and the depth of damage to the microstructures of concrete structures have been established. Moreover, a change in the chemical composition of concrete in the workshop for the production of titanium dioxide (increased SO2 content and reduced CO2) and the formation of gypsum crystals (CaSO4 2H2O) as a result of the dissimilation of microorganisms was established. Also, in the storage room for finished products, calcium citrate crystals and a violation of the formation of calcium carbonate are formed in the surface layers of concrete. In addition, the results of the study can be used to develop antimicrobial and anticorrosive protective agents to stop the biochemical corrosion of concrete in a chemical plant

http://journal.eu-jr.eu/engineering/article/download/2485/1954

Detection of the synergetic influence of chemical and microbiological factors on the properties of concrete constructions at chemical plants during the long-term service

Alina Pikhtirova

Papers

Pathogens Transmission and Cytological Composition of Cow’s Milk

Influence of Fine Additives and Surfactants on the Strength and Permeability Degree of Concrete

Reducing the biogenic corrosion of concrete in a pigsty by using disinfectants

Treatment of Subclinical Mastitis of Cows with Probiotics

Detection of the synergetic influence of chemical and microbiological factors on the properties of concrete constructions at chemical plants during the long-term service