Good Positive Relationship Research Articles

Using benzonaphthothiophenes to trace paleo-oil migration directions in the Ediacaran-Cambrian reservoirs of the central Sichuan Basin

Benzonaphthothiophenes (BNTs) are important organosulfur compounds in oil, and their concentrations and [2,1]/([2,1] + [1,2])BNT ratio have been used as migration tracers. Here we focus on the applicability of BNTs as migration tracers for abnormally heat-altered paleo-oil reservoirs. For this purpose, 57 pyrobitumen samples from the Ediacaran to Cambrian dolomite reservoirs in the central Sichuan Basin were collected and detected by gas chromatography-mass spectrometry. The results showed that most pyrobitumens of the studied samples are characterized by high concentrations of unsubstituted polycyclic aromatic hydrocarbons (PAHs), high values of fluoranthene/PAHs, pyrene/PAHs, fluoranthene/(fluoranthene + pyrene), benzofluoranthene/(benzofluoranthene + benzopyrene), and unsubstituted-to-methylated aromatic ratios due to the alteration by abnormal heating. These pyrobitumens have high concentrations of BNTs, and their three isomers show a pattern of [2,1] > [1,2] > [2,3]BNT. The BNTs concentrations display a good positive relationship with the concentrations of the abnormal heating-related PAH, while [2,1]/([2,1] + [1,2])BNT ratio has no correlation with the abnormal heating-related indices, suggesting that abnormal heating of the paleo-oil reservoirs lead to the enrichment of BNTs but has a limited effect on [2,1]/([2,1] + [1,2])BNT ratio. Moreover, [2,1]/([2,1] + [1,2])BNT ratio seem to be not affected by kerogen type and depositional environment, but increases with source rock maturity. Therefore, the [2,1]/([2,1]+[1,2])BNT is still an effective migration tracer for abnormally heated reservoirs. This ratio was applied as migration tracer in the studied area. The result suggests that the paleo-oil primarily migrated from west depression to east bulges, followed by the direction from northwest to southeast, which is congruent with the geological setting and exploration practice, demonstrating the applicability of this parameter for abnormally heat-altered oil reservoirs.

Pore Structure and Factors Controlling Shale Reservoir Quality: A Case Study of Chang 7 Formation in the Southern Ordos Basin, China

The lithofacies types, pore structure differences, and main controlling factors on the shale reservoirs are vital problems that need to be addressed in the process of shale oil exploration and development. This study explores the Luohe oilfield in the southern Ordos Basin, which is composed of organic-rich shale in the Chang 7 member, to clarify the reservoir properties and analyze major factors affecting the reservoir quality. The shale reservoir can be divided into five lithofacies using ternary diagrams of TOC, argillaceous minerals, and siliceous minerals: high organic-rich siliceous shale (HOSS), high organic-rich argillaceous shale (HOAS), medium organic-rich siliceous shale (MOSS), medium organic-rich argillaceous shale (MOAS), and low organic-rich shale (LOS). The type of organic matter in the studied samples is mainly Type I kerogen and Type II kerogen, predominantly Type II1 kerogen. The kerogen mostly lie within the mature zone in the study area. Various types of pores have been identified in the studied shale: intergranular pores, intragranular pores, intercrystalline pores, organic matter pores, and seams around organic matter. The pores are commonly nanoscale to micrometer in scale, with diameters ranging from 10 nm to several microns. The S1 content in shale is positively correlated with the macropore content, indicating that macropores in shale are the main effective oil storage spaces and are important for oil-bearing reservoirs. There is a good positive relationship between the macropore volume of shale and the content of organic matter. Organic matter in the shale can be beneficial for generating organic matter pores, dissolution pores, and seams at organic matter edge, resulting in better physical properties of shale reservoirs. There is a negative relationship between the quartz/feldspar content and macropores content, indicating that quartz and feldspar are detrimental for the macropore volume development. The lithofacies type is one of the important factors controlling the macropore volume. MOAS and HOAS are favorable lithofacies for the development of macropores. The findings of this study can be utilized for hydrocarbon exploration and development in the lacustrine shale formation of the Ordos Basin and other similar basins.

Markers of Oxidative Stress and Tyrosinase Activity in Melasma Patients: A Biochemical Investigation.

Melasma is a skin hyperpigmentary disorder that develops over time. Genetic factors, oxidative stress, female sex hormones, and UV light may all play a role in the disorder's progression. To compare the levels of oxidative stress and tyrosinase activity in melasma patients with healthy volunteers. After written consent, 130 patients were enrolled in a case-control study. 65 cases were of melasma disorder, and 65 were served as control. Homogenized skin tissues were taken and used to estimate superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx) (antioxidants), malondialdehyde (MDA) and tyrosine hydroxylase (TH). Melasma patients had lower basal levels of systemic antioxidants than healthy subjects. Tyrosinase activity was shown to be greater in lesional skin than in non-lesional skin. In controls, there was a good positive relationship between TH and MDA and an excellent negative relationship between GPx and GSH. In melasma patients, there were significant associations between CAT, GPx, SOD and MDA. Increased oxidative stress may affect tyrosinase activity and eumelanin synthesis via the anabolic pathway of melanin synthesis, according to our findings. In conclusion, we discovered a negative relationship between antioxidants and tyrosinase activity.

Experimental study on the corrosion characteristics of steel bars in concrete considering the effects of multiple factors

In this paper, twenty reinforced concrete specimens were designed for accelerated corrosion test, and a systematic study was conducted to investigate the effects of water-cement ratio, thickness of concrete cover, and spacing and quantity of steel bars on the corrosion characteristics of steel bars. The results showed that the mass loss of steel bars approximately increased with the water-cement ratio and decreased with an increase in the thickness of concrete cover. As the spacing between the steel bars in lower layer of the specimens increased, the mass loss of the steel bars in lower layer approximately showed an increasing trend. When there were more than two steel bars arranged in lower layer of the specimens, the mass loss of the middle steel bars was smaller than that of the steel bars located in the corner areas on both sides. The probability distribution type of the corrosion depth was mainly normal distribution, and the influence of water-cement ratio, thickness of concrete cover, and spacing and quantity of steel bars in lower layer of the specimens on the probability distribution was not obvious. The probability distribution type of the width of corrosion-induced cracks was mainly exponential distribution, and the influence of the spacing and quantity of steel bars in lower layer on the probability distribution was not obvious. When the water-cement ratio was large, the width of corrosion-induced cracks was less discrete from its mean value. With the increase of the quantity of steel bars in lower layer, the shape of the probability distribution curve of the width of corrosion-induced cracks tended to be flat. There was a good positive linear relationship between the mass loss of steel bars and the average width of corrosion-induced cracks, and the influence of water-cement ratio and the spacing between the steel bars in lower layer on this linear relationship was irregular. A good positive linear relationship between the maximum width of corrosion-induced cracks and the average corrosion depth of steel bars was established, which was irregularly affected by the water-cement ratio and the spacing between the steel bars in lower layer.

Fluorescence/colorimetric dual-signal sensor based on rare-earth nanosheets for quantitative detection of dopamine

A novel fluorescence/colorimetric dual-output dopamine (DA) sensor based on rare-earth nanosheets was constructed. Layered europium hydroxide (NO3-LEuH) was as the precursor, and the organic light-emitting molecule 8-naphthylamine-1-naphthalene sulfonic acid (ANS) and the surface-active molecule 1-octane sulfonate sodium (OS) were as the guests to synthesize fluorescent nanocomposite OS0.2ANS0.8-LEuH with novel emission properties. The nanocomposite was dispersed in a mixed solvent of formamide and water to prepare single-layer nanosheets. Based on fluorescence and ultraviolet absorption analysis, it was confirmed that in the range of 0.001–0.2 mM, the DA concentration had a good positive linear relationship with the fluorescence quenching efficiency F0/F and absorbance, and the response detection limits of the fluorescence method and the colorimetric method were 0.29 μM and 0.058 μM, respectively. The sensor has high specificity recognition ability and can be used for the detection of actual samples, and the dual-signal output sensing strategy greatly improves the accuracy and reliability of detection.

FAKTOR PROTEKTIF DAN FAKTOR RISIKO YANG MEMPENGARUHI SELF-ESTEEM PADA REMAJA DENGAN DISLEKSIA

Abstract. Adolescence is a transitional period between childhood and adulthood. During this time, the development of self-esteem is critical as it can have a significant impact on future growth. This phase is not exclusive to adolescents with dyslexia, who tend to have lower self-esteem, which indicates the importance of identifying factors of self-esteem in adolescents with dyslexia. This study aims to identify the protective and risk factors that affect the self-esteem of dyslexic adolescents. The study utilized qualitative methods and employed a case study approach. The research was based on the experiences of two participants who were siblings with dyslexia disorder and came from different family backgrounds. The analytical technique used was inductive thematic analysis. The results showed a number of protective factors such as positive family relationship, positive parenting, personality and self-reflection, good academic performance, academic support, and positive relationship with as it peers, and risk factors such as poor family relationship, negative parenting, poor academic performance, academic difficulties, poor relationship with peers, and negative self-acceptance. The most significant factor impacting adolescents with dyslexia is their family relationships and the parenting models implemented.

Optimization studies for extraction of antioxidants from Mucuna sanjappae seeds: A promising natural drug for oxidative stress management

Introduction and Aim: Cellular oxidative stress is responsible for various human diseases. Dietary antioxidant supplements from natural plants have good potential to reduce increased oxidative stress thus protecting from further medical complications. Genus Mucuna is well known for its promising health benefits. A common species of Mucuna, M. pruriens is being used for oxidative stress related diseases treatment. However, many species of this genus are not scientifically explored for their health-related beneficial properties. In the present study, we have made effort to investigate secondary metabolites composition and antioxidant potential in a Mucuna species namely M. sanjappae. In this work, we tried to understand superior system for secondary metabolites (total phenolics and flavonoids content) extraction and antioxidant activity in M. sanjappae seeds was demonstrated. Methodology: Four different solvents viz., water, methanol, ethanol, and acetone in combination with four different extraction conditions (static, shaking, microwave and sonication) each with three different times have been studied. Total 48 extract samples were generated which were used for total phenolics, total flavonoids content along with antioxidant activity (DPPH, DMPD and FRAP) determination. Further major phenolics were identified using HPLC system. Results: Water showed highest TPC and TFC level during microwave method for 120 seconds (81.627±0.728 mg GAE g-1 and 648.06±4.37 mg RUE g-1 respectively). The highest antioxidant activity was also found in M. sanjappae seeds extracted in water. RP-HPLC quantification of phenolics revealed tannic acid and gallic acid as predominant compounds. Correlation analysis indicated that the antioxidant of different extracted samples demonstrated a good positive relationship with TPC and TFC. Conclusion: Present attempt indicated that, simple solvent water along with microwave method can be used for maximum antioxidants extraction from M. sanjappae seeds. This Mucuna species may be further studied to exploit as a natural antioxidant source in medicine and food etc.

The Potential of Bacilli-Derived Biosurfactants as an Additive for Biocontrol against Alternaria alternata Plant Pathogenic Fungi.

Fungal diseases caused by Alternaria alternata constitute a significant threat to the production and quality of a wide range of crops, including beans, fruits, vegetables, and grains. Traditional methods for controlling these diseases involve synthetic chemical pesticides, which can negatively impact the environment and human health. Biosurfactants are natural, biodegradable secondary metabolites of microorganisms that have also been shown to possibly have antifungal activity against plant pathogenic fungi, including A. alternata being sustainable alternatives to synthetic pesticides. In this study, we investigated the potential of biosurfactants of three bacilli (Bacillus licheniformis DSM13, Bacillus subtilis DSM10, and Geobacillus stearothermophilus DSM2313) as a biocontrol agent against A. alternata on beans as a model organism. For this fermentation, we describe using an in-line biomass sensor monitoring both permittivity and conductivity, which are expected to correlate with cell concentration and products, respectively. After the fermentation of biosurfactants, we first characterised the properties of the biosurfactant, including their product yield, surface tension decrement capability, and emulsification index. Then, we evaluated the antifungal properties of the crude biosurfactant extracts against A. alternata, both in vitro and in vivo, by analysing various plant growth and health parameters. Our results showed that bacterial biosurfactants effectively inhibited the growth and reproduction of A. alternata in vitro and in vivo. B. licheniformis manufactured the highest amount of biosurfactant (1.37 g/L) and demonstrated the fastest growth rate, while G. stearothermophilus produced the least amount (1.28 g/L). The correlation study showed a strong positive relationship between viable cell density VCD and OD600, as well as a similarly good positive relationship between conductivity and pH. The poisoned food approach in vitro demonstrated that all three strains suppressed mycelial development by 70-80% when applied with the highest tested dosage of 30%. Regarding in vivo investigations, B. subtilis post-infection treatment decreased the disease severity to 30%, whereas B. licheniformis and G. stearothermophilus post-infection treatment reduced disease severity by 25% and 5%, respectively. The study also revealed that the plant's total height, root length, and stem length were unaffected by the treatment or the infection.

Quantitative Assessment of Treatment Response in Metastatic Breast Cancer Patients by SPECT-CT Bone Imaging-Getting Closer to PET-CT.

Cancer represents the major cause of death mainly through its ability to spread to other organs, highlighting the importance of metastatic disease diagnosis and accurate follow up for treatment management purposes. Although until recently the main method for imaging interpretation was represented by qualitative methods, quantitative analysis of SPECT-CT data represents a viable, objective option. Seventy-five breast cancer patients presenting metastatic bone disease underwent at least two Bone SPECT-CT studies using [99mTc]-HDP between November 2019 to October 2022. Our findings show a good positive relationship between the qualitative methods of imaging interpretation and quantitative analysis, with a correlation coefficient of 0.608 between qualitative whole body scintigraphy and quantitative SPECT-CT, and a correlation coefficient of 0.711 between the qualitative and quantitative interpretation of SPECT-CT data; nevertheless, there is a need for accurate, objective and reproducible methods for imaging interpretation, especially for research purposes. Quantitative evaluation of the SPECT-CT data has the potential to be the first choice of imaging interpretation for patient follow up and treatment response evaluation, especially for research purposes, because of its objectivity and expression of uptake changes in absolute units.

Fractal characteristics of rocks and mesoscopic fractures at different loading rates

Uniaxial compression tests were conducted on rocks under different loading rates to analyze their effect on rock fragmentation. The fractal dimension of the macroscopic fragmentations of the rocks were then calculated by combining the fractal theory. Based on scanning electron microscopy (SEM), the macroscopic failure characteristics and mesoscopic fracture morphology characteristics of the rocks under different loading rates were compared and analyzed; the mesoscopic fractal dimension of the fracture was calculated using the box dimension method. The results demonstrate that when the loading rate is increased from 0.001 to 0.05 mm/s, the average fragmentation distribution coefficient decreases from 18.99 to 16.37 mm. As the loading rate increases, the fragmentation distribution coefficient gradually decreases, and the rock sample breaks; the degree of failure gradually increases, and the failure mode of the rock transforms from tension to shear failure. The SEM analysis reveals that under low loading rates, an intergranular fracture indicates the primary failure mode. The macroscopic performance primary presents tensile failure; as the loading rate increases, the range of the transgranular fracture gradually increases, and the failure mode evolves from an intergranular to transgranular fracture. The fractal dimension of the mesoscopic structure of the rock fracture tends to increase with an increase in the loading rate, and demonstrates a good positive relationship by fitting with the macrostructure fractal dimension. A larger fractal dimension of the microstructure of a rock fracture indicates more complex structure of the fractured surface. This study provides a better understanding of the meso-rock failure mechanism, and presents significant findings regarding ore rock fragmentation and rockburst prevention.

A comprehensive analysis of pore structures and performances of mineral admixtures modified recycled aggregate concrete based on experiment and theory

Recycled aggregate concrete (RAC) is an important form of construction waste resource utilization, but the existence of multiple interface transition zone (ITZ) leads to complex pore defects in RAC, which seriously weakens its mechanical properties and chloride ion permeability. In this paper, fly ash (FA), silica fume (SF) and mineral powder (SL) admixtures were incorporated into RAC for improving the pore structure of RAC. The effects of admixtures on the pore structure parameters and pore size distribution of RAC were detailly analyzed by means of back scattering electron imaging (BSE), mercury intrusion porosimetry (MIP) and fractal dimension theory (FDT). And the micro characteristics of porosity and pore structure in ITZ were quantitatively described. The results clearly show that the appropriate amount of admixture can reduce the porosity, average pore diameter and the maximum aperture of RAC. Furthermore, the macropores and capillary pores were significantly decreased and gradually changed into transition pores and gel pores. The refinement of pores increases the compactness of RAC, particularly the pozzolanic effect of SF. The newly generated CSH gel and the filling effect of SF greatly decrease the porosity of ITZ. In addition, the fractal dimension (FD) of pore volume exhibits a good positive linear relationship to the compressive strength and chloride ion permeability resistance of RAC.

Arbitrarily shapeable and conductive hydrogel with “Magic Cube” like structure for real-time monitoring and promoting wound healing

Developing hydrogel dressings for chronic non-healing wounds in irregular-shaped or moveable sites has great practical applications. In this work, a novel polyelectrolyte composite hydrogel (HSa) was fabricated from chitosan quaternary ammonium salt (HACC) and sodium alginate (SA) through blending and acid-treated process. The positive charges of HACC and negative charges of SA self-assembled and intertwined to form a “Magic Cube”-like structure. The amino groups of HACC were protonized and the Na + of SA was replaced by proton after acid treatment, further strengthening the interactions between the two chips of “Magic Cube”. HSa hydrogel was proven to be arbitrarily shapeable with high flexibility (tensile strain is around 280%). Due to free Cl − , HSa hydrogel presented good conductivity (1.14 × 10 −3 S/cm) and positive linear relationship between its electrical resistance change and area change, which denoted its ability to monitor joint movement or subtle shrinkage. HSa hydrogel exhibited good biocompatibility and was further applied as dressing in an irregular-shaped wound model. HSa hydrogel could significantly accelerate the wound healing by elevating collagen deposition and vessel formation. Simultaneously, HSa hydrogel could monitor the wound closure in real-time. Therefore, HSa hydrogel had multifunctional potential for wound healing and monitoring, especially for irregular-shaped or movable sites. • A simple strategy for fabricating arbitrarily shapeable and conductive hydrogel. • HSa hydrogel has a “Magic Cube” like structure. • HSa hydrogel has good hemostasis effects and biocompatibility. • HSa hydrogel combines wound pro-healing and real-time monitoring functions. • HSa hydrogel could be beneficial for chronic non-healing wounds.

Mild preheating improves cholesterol-lowering benefits of soy protein via enhancing hydrophobicity of its gastrointestinal digests: An in vitro study

Although the cholesterol-lowering benefits of soy proteins have been well recognized for a long time, the importance of protein structural characteristics to their cholesterol-lowering activities is little understood. In the work, we reported that a mild preheating at 95 °C for 20 min could remarkably improve the cholesterol-lowering activities of soy protein isolate (SPI) after an in vitro simulated pepsin-pancreatin digestion, including cholesterol and bile acids binding capacities (CBC and BBC), and inhibition of micellar cholesterol solubility (MCI), while an extensive preheating at 121 °C contrarily impaired its potential. The improvement of the cholesterol-lowering activities of the pepsin-pancreatin digest by the mild preheating was largely associated with the facilitated formation of digestion-induced peptide aggregates with high surface hydrophobicity (Ho) in the digest. The final pepsin-pancreatin digest of the mildly preheated SPI could be fractionated using a gradient ethanol precipitation technique at ethanol concentrations of 20–80% (v/v). The Ho and cholesterol-lowering activities of peptides in the resultant precipitate or supernatant fractions considerably varied. The ethanol-precipitated fractions at ethanol concentrations of 40–80%, with high Ho but low solubility (in water), largely contributed to the CBC of the digest, while all the precipitates obtained at ethanol concentrations of 20–80% dominated the BBC of the digest. In contrast, the soluble peptides in 80% ethanol were mainly responsible for the high potential of the digest to inhibit micellar cholesterol solubilization. In general, a good positive relationship between the CBC (or BBC) and Ho could be well observed for the pepsin-pancreatin digests of SPI, or their fractions. The MCI of the mildly preheated SPI digest was largely ascribed to the action of soluble peptides in 80% ethanol. The results demonstrated that the choice of preheating conditions (especially temperature) is of vital importance for optimal cholesterol-lowering benefits of soy proteins. The findings are also of interest for understanding the molecular mechanisms of the cholesterol-lowering activities of soy proteins.

Evolution of predictive emissions in PETRONAS

The effect of global warming and unprecedented black swan events give rise to innovative solutions to keep manufacturing companies stay afloat. Many countries have started to employ more stringent emissions limits and stricter monitoring enforcements. PETRONAS is not spared from these policies and with the enforcement of Clean Air Regulation Act (CAR) 2014, PETRONAS embarked on its emissions monitoring via statistical modelling methods. Traditional analysers are still employed for the emissions monitoring, but the focus of the paper is to spotlight the efforts in utilising soft sensors in ensuring compliance to CAR 2014. Soft sensors are predictive models developed to infer primary parameters. The models can be derived via statistical tools or based on first principles using chemical engineering knowledge. The use of soft sensors is not only pervasive in the manufacturing industry but is also widely used elsewhere as it provides an indication of the future position of the primary indicators for the specific industry. The paper will also provide some insights on potential next steps in supporting PETRONAS efforts in its Sustainability Agenda. It also tells the story of collaborative efforts in maintaining good positive governance and relationship with its stakeholders.

Primary study of germanium isotope composition in sphalerite from the Fule Pb–Zn deposit, Yunnan province

The Sichuan–Yunnan–Guizhou metallogenic province in southwest China is one of the most important low-temperature metallogenic domains in the country, and more than 400 Pb–Zn deposits and/or mineralization points are located in this area. The Fule deposit is better known that the other Pb–Zn deposits in the region because it is extremely highly enriched with dispersed elements, including Ge, Ga, and Cd. Based on information obtained from our previous studies, the contents of Ge and its isotopic compositions in sphalerite are investigated herein. Results show that the Ge content ranges from 60 ppm to 141.5 ppm, and δ74/70Ge values vary from −6.57‰ to 0.97‰. In this respect, −6.57‰ is the most negative Ge isotope composition value reported in any sphalerite or seafloor sulfides to date. The Cd and Ge contents in sphalerite have a good negative relationship, and it is suggested that the mechanisms of Cd and Zn substitution are responsible for the low incorporation of Ge and relate to the high Cd content (up to 3%) of the sphalerite. In addition, there is a good positive correlation between the Ge contents and δ34S values, which was likely triggered by variations of fluid temperature. In the same hand specimen, light Ge isotope is more likely to be enriched in dark sphalerite rather than light sphalerite, similarly to Cd isotope distribution in dark and light-colored sphalerite. In addition, Cd and Ge isotope compositions, measured in an ore profile from SBFL22 to SBFL26, show a good positive relationship, suggesting that the fractionation mechanisms between Cd and Ge isotopes may be similar and they were controlled by kinetic fractionation during sphalerite precipitation. Based upon previous limited studies, we conclude that Ge in the Fule deposit is derived from mixing sources and sediment is likely the dominant one.

Impact of Formative Evaluation Modes on Learning Outcomes among Senior Secondary Agricultural Science Students in Uyo, Akwa Ibom State

This study examined the effect of formative evaluation modes on secondary school agricultural science students’ learning outcomes in Uyo, Akwa Ibom State, Nigeria. It was a pre-test and post-test quasi-experimental/control group research that relied on multi-stage sampling technique in the selection of respondents. Five (5) instruments developed and validated by the researchers were used to generate data from 200 SS11 students exposed to Agricultural science and farming techniques in secondary schools. Collected data were analysed using mean scores and standard deviation as well as Analysis of Covariance (ANCOVA) at .01 level of significance. Formative evaluation modes with feedback and remediation, which enabled respondents, develop good study habit and positive interpersonal relationship with their instructors and peers have proved to be very effective in the assessment and improvement of students’ learning outcomes. The improvements in respondents’ performances were observed in both achievements in and attitude to learning Agricultural science. It could thus be concluded from this study that formative evaluation modes with feedback and remediation are effective in improving farmers’ achievement in and their attitude to learning more about Agricultural science. Formative evaluation modes with feedback and remediation enabled young farmers to engage in consistent studying. It allowed the farmers to be exposed to different formative evaluation techniques such as peer assessment, projects, group assignment instead of the usually test and individual assignment that they were used to. Need for Agricultural science instructors to acquire necessary skills in the development of various formative evaluation modes/techniques needed for the assessment of the cognitive and affective domains of the young farmers was raised. Such techniques include written quiz, end-of-lesson assessment, peer assessment, individualized task, project, group assignment, attitudinal scales, and socio-metric scale among others.

Influence of evaporation rate on pore size distribution, water loss, and early-age drying shrinkage of cement paste after the initial setting

The influence of the water evaporation rate on early-age drying shrinkage of cement paste is investigated. To measure shrinkage, three mixed groups with different water–cement ratios (w/c’s) were studied over a period of 72 h. The 72-h early-age drying shrinkage, starting from the initial setting time, was measured. The pore size distribution (PSD) was measured using mercury intrusion porosimetry. The results show that the increase of the evaporation rate leads to a large increase in the early-age drying shrinkage. During the first six hours, each group had a good positive relationship between the shrinkage ratio and water loss ratio, and the shrinkage ratio was slightly greater than water loss ratio. Different water evaporation rates influence the most probable pore diameter of cement paste, which increases as the water evaporation rate increases. However, the porosity of the bulk paste and volume of mesopores was not consistent with the rule of the most probable pore diameter. A higher water evaporation rate resulted in a lower pore volume within 26 nm. Therefore, a parameter rs, which can explain the contradiction between the increase of shrinkage and volume of mesopores, was calculated from the water loss and cumulative PSD. The total volume of mesopores may not be the dominant factor in early-age shrinkage, but the most probable pore diameter, parameter rs, and relationship between them can provide a better index of drying shrinkage for the early-age of cement-based materials. Furthermore, in the paste with a w/c of 0.28, rs and drying shrinkage show a linear relationship.

Characterization of multi-type pore structure and fractal characteristics of the Dalong Formation marine shale in northern Sichuan Basin

ABSTRACT Pore structure and fractal characteristics are the discussion hotspots in the theoretic field of shale gas reservoir, however, less attention has been paid to the quantitatively characterization of different types of shale pores. Various types of micro-pores developed in the Dalong shales, including inter-particle pore, intra-particle pore, inter-crystal pore, dissolved pore, organic matter (OM) pore, and micro-fracture. These pores are dominated by nanopores with the size diameters of < 10 and 30–600 nm. The shale pore structures have the high complexity and heterogeneity, with the fractal dimensions of 2.45–2.80, which have good positive relationship with the porosity. TOC contents and brittle minerals dominate the development of OM pore and inorganic pores, respectively. OM pores are the most significant contributor to the complexity and heterogeneity of pore structures. Dalong shales have good shale gas content and hydrocarbon generating potential for commercial exploration of shale gas resources. Shale gas is mainly stored in shale pore networks, while the pores within clay mineral layers play the dominate role in adsorbing shale gas. Large amount of OM pores in shales generating from the hydrocarbon generation progress from kerogen support the shale gas-generating potential.

Method for quantification of antioxidant capacity of processed fruit juices exploring the formation of the Fe(II)/3-hydroxy-4-nitroso-2,7-naphthalenedisulfonic complex

The formation of the Fe(NRS)34− complex was used in a modified spectrophotometric method to quantify the total antioxidant capacity (TAC) of processed fruit juice samples. The procedure is based on the reduction of Fe(III) to Fe(II) in aqueous buffered solution (Tris; pH 8.0) containing the 3-hydroxy-4-nitroso-2,7-naphthalenedisulfonic acid (H2NRS). The absorbance values at 730 nm (A730 nm) of the Fe(NRS)34− complex obtained with juice samples were compared with A730 nm values obtained with a standard ascorbic acid solution and then subsequently used to quantify and express the TAC of the samples. Good positive relationship between TAC values in the analysed samples (grape, orange, passion fruit, cashew, peach, and strawberry) was found for both the Fe(NRS)34− complex method (proposed method) and ABTS•+ radical-free method (used as reference method). The TAC values obtained with Fe(NRS)34− and ABTS•+ also showed a positive correlation with the Folin–Ciocalteu index values. Fructose, glucose, BHT, and BHA did not interfere in the TAC quantification of the processed fruit juice samples with the proposed method. However, ascorbic acid (natural or added as additive, E300) and its derivatives (E301, E302, E303, E315, and E316) did interfere positively. As a 10-fold dilution is required and the absorbance measurements are performed at 730 nm, the proposed method was not subject to colour interference from the tested samples. The procedure suggested here is simple, easy to perform, reproducible, does not use organic solvents, and does not need expensive equipment.

Dielectric properties of raw milk as influenced by frequency, salts, and salt contents

AbstractTo understand the effect of salts and salt contents on dielectric properties (dielectric constant ε′ and dielectric loss factor ε″) of milk, dielectric properties of raw cow's milk samples at the total salt content (in mass) of 0.75–0.87%, 0.75–0.93%, and 0.75–0.90% by adding NaCl, MgCl2, and KCl, respectively, were obtained from 19 to 3,000 MHz at 25 °C using an impedance analyzer. The results showed that ε′ decreased with increasing frequency, and ε″ changed with “V” shape and had minimums at about 1,500 MHz. At a given frequency and the same salt addition level in molar, the milk added with NaCl and MgCl2 had the smallest and the biggest ε″, respectively. At about 40 MHz, ε′ had a very good positive linear relationship with the total salt content of milk, whose coefficients of determination were 0.96, 0.98, and 0.95 for NaCl, MgCl2, and KCl, respectively. ε″ increased linearly with increasing total salt contents with the coefficients of determination higher than 0.99 below about 900 MHz and higher than 0.86 above 900 MHz no matter for which salt.Practical applicationsThis work shows that there were linear relationships between dielectric properties and total salt contents. The study is helpful to understand the influence of salts and salt content on dielectric properties of raw cow's milk, and it offers useful information for developing portable salt detector based on dielectric properties in the future.