Исследование динамики окислительной порчи сливочного масла, упакованного в модифицированную пленку с антиоксидантной добавкой

Background: An eggshell is the hard outer covering of an egg that serves to protect it from damage, microbial contamination and desiccation. The major component of the eggshell is calcium carbonate, which provides it with hardness and strength. Calcium carbonate content of eggshells contributes to the overall quality of the egg and eggs are an essential component of human and animal nutrition. Eggshells containing high calcium carbonate can also be processed and used as calcium supplement for bone and teeth health in vulnerable populations. Objectives: This study determined the calcium carbonate content of brown and white chicken eggshells sourced from Lagos markets and the effect of boiling on same. Materials and method: Eggs were sourced randomly from three markets in Lagos metropolis and the shells were washed and dried. The dry shells were pulverized and analyzed for calcium carbonate using the back titration method. Each sample (0.5 g) was reacted with excess 1.0 M HCl and the excess acid titrated with 0.1 M NaOH. The calcium carbonate content of each sample was calculated from the difference between the total number of moles of HCl used and that titrated as excess. Results: The results show that the eggshells studied have high calcium carbonate content and brown eggshells contained higher levels of calcium carbonate (95%) than white eggshells (91%). Boiling did not significantly reduce the calcium carbonate content of both brown and white eggshells. Eggshells from the three markets were similar in their content of calcium carbonate. Conclusion: This study shows that brown eggshells have a higher calcium carbonate content than white eggshells and boiling of eggs does not significantly reduce the calcium carbonate content of the shells.

The mechanical behavior of sands treated using microbially induced carbonate precipitation (MICP) has been investigated at the macroscale and the microscale. Triaxial and confined compression tests with embedded shear and compression wave (S-wave and P-wave) sensors were conducted on two MICP-treated sands, Ottawa 50/70 and 20/30 silica sands. Triaxial compression tests were conducted at three different confining pressures (25, 50, and 100 kPa). Tests were also performed at calcium chloride (CaCl2) concentrations of 0.1 and 0.3 M, resulting in specimens with average calcium carbonate (CaCO3) content ranging from 1.5 to 2.5% for the 50/70 sand and from 1 to 1.6% for the 20/30 sand. In contrast to previous research, the results of triaxial tests presented in this paper show an increase of the soil strength even at 1% calcium carbonate content. After the tests, samples taken from the specimens were utilized to measure the CaCO3 content and to perform analysis using scanning electron microscopy (SEM) ...

Field implementation to resist coastal erosion of sandy slope by eco-friendly methods

Carbonate neoplasms are the characteristic feature of the black soil profile. The study of morphological and micromorphological characteristics and chemical composition gives an idea of the black soil genesis and serves as the diagnostic feature of classification units of them. The study of migration carbonate in the chernozem are of great scientific and practical interest (Afanasyeva, 1996). Nowadays the issues of migration carbonates, as well as the extent of the manifestation of this process in the soil profile need further researching, which is important as carbonates has one of the main role in basic soil processes, in particular, they affect the concentration and activity of calcium ions in the soil solution, the composition of the soil absorbing complex and pH in the soil solution. Carbonate neoplasms contribute to the formation of strong coagulation structures, which increases soil fertility and harvest agricultural crops, provides resistance against the wind, prevents reduction of the upper fertile soil layer, increases mobility of some chemical elements and improves such physical characteristics of soil as density, permeability and porosity (Goncharova, 1983). The aim of our work was to study the content of calcium carbonate in the soil profile of the test section 201–L under of the acacia plantations crops of forest ecosystems and to determine of their distribution in the soil genetic horizons. According to the aim of our work of we has the following tasks: to give a general characterization of carbonates of calcium in Chernozem usual, to perform sampling of the genetic horizons of the soil profile of test section 201–L, to determine the content of carbonates by conventional gravimetric methods; to study the features of the content of carbonates in soil profiles of test section 201–L; to conduct statistical processing of the obtained data; to formulate conclusions of the performed research. Soil samples were selected according to the standard technique in genetic horizons of the soil profile on three times (Fedorets, 2009). Determination of the percentage content of carbonates in the soil was performed by the gravimetric method, which is based on weight loss of soil due to discharge of CO2 during the destruction of carbonates with acid. It should be noted that the method can be applied in the case of the carbonates content up to 70 % (Travleev et al., 2009). The average coefficient of variation of carbonates of calcium content in genetic horizons of the soil profile is 77.5 %. This is quite a high rate, so as General it is considered that if the value of the coefficient of variation is less than 33 %, the result is considered homogeneous if more than 33 %, it is inhomogeneous. Based on this observation, we conclude that carbonate calcium has inhomogeneous redistribution of genetic horizons of test section 201–L. Regarding the reliability of the obtained data, we can see that the standard error calculations for each of the horizons does not exceed 0,34, which in turn confirms the accuracy of the our data. According to our calculations the lowest content of calcium carbonate is 1.47 % in the first horizon, and biggest – 16,07 % in the genetic horizon Ph (70–90 cm). These results are extending the current understanding of the processes of formation and distribution of calcium carbonate in the genetic horizons of the soil profile of the Chernozem ordinary. The data of percentage of calcium carbonate may be used in the solution of the question of the genesis, evolution and classification of soils, the obtained data can serve as the basis of the research the conditions of pedogenesis under the influence of natural climatic fluctuations and anthropogenic factors.

The precipitation and dissolution of carbonate minerals of divalent metal ions such as calcium carbonate (calcite and aragonite) and calcium magnesium carbonate (dolomite) are of considerable importance in a wide variety of fields such as limnology (1), oceanography (2), and sedimentology (3). The crystal growth of calcium carbonate also has important applications in water purification technology (4-7). The concentration of calcium carbonate in many natural waters is equal to or greater than the saturation level (1) and as a consequence, calcium carbonate precipitation and crystal growth takes place in water treatment and desalination facilities. The resulting scale formation on heat transfer surfaces during evaporative desalination may significantly increase the cost of potable water (5, 6). A recent study (8) has shown that calcium carbonate surfaces are effective nucleators of calcium sulfate dihydrate scale crystals. In many scale forming and corrosion processes, it may therefore be necessary to take into account the possibility of epitaxial growth of one mineral upon another. Since carbonate concentrations in the environment are usually quite appreciable, calcium carbonate phases are likely candidates as the first-formed solids. Since the solubility of the calcium carbonate polymorphs decreases with increasing temperature, the problem is also exacerbated by relatively high ambient temperatures in many processes.

The development of rapid, accurate, cost effective methods to determine soil physical and chemical properties is important for sustainable land management. In the last two to three decades, the interest in using visible and near infrared (Vis-NIR) spectroscopy as an alternative method for determining soil properties has increased. To obtain reliable predictions of soil properties, multivariate calibration techniques such as Partial Least Squares Regression (PLSR) are commonly used to correlate the spectra with the chemical, physical and mineralogical properties of soils.The objective of the paper was to assess the potential of Vis-NIR spectroscopy coupled with PLSR to determine soil chemical and physical properties such as organic carbon (SOC), sand, silt, clay, and calcium carbonate (CaCO3) contents in a sample site of southern Italy.Spectral curves showed that the soils could be spectrally separable on the basis of chemical and physical properties. PLSR calibration models were derived for each of the soil properties and were validated with an independent data set. The optimum number of factors to be retained in the calibration models was determined by leave-one-out cross-validation. The accuracy of the calibration and validation models for the different soil properties was evaluated with the coefficient of determination (R2) and the root mean squared error (RMSE). The results showed that predictions were satisfactory for all soil properties analyzed with high values of R2 > 80.A combination of Vis-NIR spectroscopy and multivariate statistical techniques, therefore, can be used as a rapid, low cost and quantitative means of characterizing the soils of southern Italy.

A data-driven approach for assessing the wind-induced erodible fractions of soil

Plaque on the teeth of smokers comes from cigarette smoke tar that settles on the surface of the teeth and roots of the teeth, causing the tooth surface to become rough and easier to stick with food debris and germs that will react making it easier for plaque to form. This study was aims to determine the safety and effectiveness of removing plaque in palm shell activated charcoal toothpaste with a concentration of 12% calcium carbonate combination of 25%. The content of calcium carbonate as an abrasive against the dental plaque of active smokers. The method used was measurement the plaque index score according to Turesky before and after using toothpaste on 20 panelists of active smokers. The decrease in plaque index in the use of toothpaste by using Wilcoxon's non-parametric statistical test, namely P = 0.000 (Sig <0.05). The results showed that toothpaste in the first week was able to reduce dental plaque by 59% compared to positive control by 45% and without activated charcoal by 34%. Toothpaste and positive control in the second week were able to remove dental plaque by 100%, while toothpaste without activated charcoal and calcium carbonate was only able to remove dental plaque by 68%. It can be concluded that palm shell activated charcoal toothpaste with a concentration of 12% combined with 25% calcium carbonate is safe and effective in removing plaque on the teeth of smokers.Keywords: dental plaque, efficacy, palm shells

Microbial-induced calcium carbonate precipitation (MICP) has attracted much attention as a promising technology for soil improvement in the infrastructures of marine engineering. This paper introduces a novel numerical sample preparation technique for MICP-treated sand, with particular attention paid to the distribution patterns of calcium carbonate, including contact cementing, bridging, and grain coating. The effect of calcium carbonate content (CCC) on the deformation and failure mechanism is studied at macroscopic and granular scales. The findings show that a small amount of calcium carbonate can quickly increase the strength of sand. The strength improvement and deformation control of MICP technology are better than those of traditional compaction treatment. As the calcium carbonate content increases, the mechanical coordination number of the sand also increases, indicating a more stable microstructure of the sand phase. In the contact bonding mode, initial failure occurs as shear failure between sand and calcium carbonate. In the bridge mode, initial failure manifests as shear failure between calcium carbonate particles. In the coating mode, initial failure occurs as tensile failure between sand and calcium carbonate. Calcium carbonate contributes to a reduction in both sliding and rolling movements among sand particles.

Bottom ash (BA) is the main residue left by municipal solid waste incineration (MSWI). As the circular economy is strengthened, the use of BA in civil engineering is increasing, but its successful use is hampered by heavy metal leaching. In this study, we investigated the influence of natural weathering (6 months) on the stabilization of heavy metals (Cu, Zn, and Pb) with different particle sizes in MSWI BA. Natural weathering is the most popular and cost-effective treatment method for BA. During this process, calcium carbonate (CaCO3) is produced, which causes a reduction in heavy metal leaching. We used the following methods in the analysis: The fractionation of BA, XRF, and XRD; an extraction test (LST EN 12457-2:2003); and AAS. The results showed that the concentrations of all elements in BA decreased during natural weathering. An analysis of the mineralogical composition showed a very high (>20%) content of calcium carbonate (CaCO3). The calcium carbonate content increased by 3.2% during weathering because the Ca(OH)2 in fractions <5.6 mm and <40.0 mm was hydrolyzed to CaCO3. Our analysis showed that the metal concentrations (Cu and Pb) in untreated MSWI bottom ash eluate exceeded the limit values, and thus it cannot be used in civil engineering. After three months of stabilization, the heavy metal concentrations were less than the limit values.

The biocementation of sand through calcite precipitation is a promising approach that has been investigated for nearly 10 years as an attempt to find practical solutions to ground improvement challenges due to sustainability considerations. This study aims to evaluate the effect of the precipitation pattern on the unconfined compressive strength (UCS) of sand treated through the enzyme-induced calcite precipitation (EICP) technique. The microscale characteristics of calcium carbonate (CaCO3) (spatial distribution, shape, size and amount) under three different precipitation conditions (EICP, skim-milk-added EICP and EICP on calcite-nanoparticle-coated medium) were investigated through microfluidic chip experiments. The outcomes of these observations were linked to the UCS of sands treated under each of these conditions through column tests. The densely packed, homogeneous and small-sized rhombohedral crystals promoted by the nanoparticle-coated condition led to lower UCS values (maximum of 0.15 MPa at 5% calcium carbonate content). In contrast, sparsely distributed, less uniform and large-sized spherical crystals yielded higher values (maximum of 1.4 MPa at 3.9% calcium carbonate content). The precipitation pattern of calcium carbonate was found to influence significantly the UCS of EICP-treated sand.

This study was conducted to assess the effects of fertilizing regime and orchard planting age on soil calcium contents and stocks in the apple orchards on the Loess Plateau. The apple orchards in Luochuan County, one of the best regions for apple plantation in the world, were selec-ted in this study. The contents of calcium carbonate,water-soluble calcium and exchangeable cal-cium at 0-100 cm soil layer under different fertilizing regimes and various planting ages were mea-sured, their stocks were calculated and their variation features were analyzed. The results showed that soil in the apple orchards in the study region was characterized by the decline in calcium contents. The decline was more serious in apple orchards with long-term application of chemical fertili-zer than in those with combined application of chemical fertilizer and farmyard manure. The average contents of calcium carbonate, water-soluble calcium and exchangeable calcium at 0-100 cm soil layer in apple orchards with long-term application of chemical fertilizer decreased by 38.8%, 25.4% and 5.6% respectively than those in the apple orchards with long-term application of both chemical fertilizer and farmyard manure. The stocks of calcium carbonate, water-soluble calcium and exchangeable calcium decreased by 36.4%, 26.0% and 4.3%, respectively. The decline of soil cal-cium was aggravated with the increase of orchard planting age. The contents of calcium carbonate, water-soluble calcium and exchangeable calcium at 0-100 cm soil layer in orchards of more than 25 years of planting age decreased by 48.8%, 69.4% and 39.5% respectively, compared with orchards of less than 10 years of planting age, and the stocks decreased by 40.8%, 64.1% and 33.0%, respectively. These results indicated that either long-term application of chemical fertilizer or long-term plantation of apple trees obviously depleted soil calcium carbonate, water-soluble calcium and exchangeable calcium. Therefore, it was recommended that application of chemical fertilizer and farmyard manure should be combined to mitigate soil calcium decline, and calcium management should be strengthened in apple orchards of more than 25 years of planting age. The fertilizing regime was a driving factor of soil calcium decline which had a significant temporal (orchard planting age) and spatial (soil depth) effect.

Study of microbially-induced carbonate precipitation for improving coarse-grained salty soil

The study examines how different concentrations of calcium citrate (CCI), calcium carbonate (CCA), calcium gluconate (CGL) and calcium chloride (CCH) affect the gelling properties of rice starch-soybean protein composites and calcium bioaccessibility. Results showed CCI and CCA had weaker shielding effects on electrostatic repulsion than CGL and CCH, as they increased the pH while CGL and CCH decreased it. CCI and CCA promoted protein β-sheet structures and enhanced starch crystallinity, facilitating bicontinuous and packed networks, respectively. CGL and CCH induced protein β-turn structures and enhanced starch crystallinity, facilitating disordered aggregation networks. Gels with CCI and CCA have superior properties, while those with CGL and CCH are inferior. The gel with 30mmol CCA has the highest strength (102.8g) and water-holding capacity (94.6%), while that with 30mmol CCH has the lowest (17.1g and 84.9%). CCI exhibits the highest bioaccessibility. These results guide calcium-containing texture-modified food design.

A comparative analysis of calcium carbonate content in the egg shells of eight selected chicken species (Naadankozhi ,Karinkozhi, Giriraja, White leghorn, Black silky, Porukozhi, Naked neck hen and White silkie) and six species of ducks (Vigova, Chara, Chembelli, Plain duck, Nadan Tharavu and Patha Tharavu) were conducted.It was noted that even though higher level of calcium was present in all variety of egg shells, in chicken variety the highest calcium carbonate was noticed in Aseel (Porukozhi) eggshell and it was 92.90% of CaCO 3 and the lowest was in Silky's chicken egg shell and it was 86.75% of CaCO 3 .In duck the highest calcium carbonate was noticed in Plain duck and it was 91% whereas the minimum noted was in Patha Tharavu and its egg shell containing 75% of CaCO 3 .Amount of calcium carbonate always associated with the hardness and strength of the egg shell.Hence Porukozhi's egg shell has highest hardness and White silkie species has lowest.In ducks plain duck showed high hardness and patha tharavu with minimum.