Decrease Of pH Value Research Articles

Curative impacts of Ethanoic Extract of Laportea aestuans (L) Chew in Aspirin-Induced Ulcerative compromise in Male Rats

Toxicity of Non-steroidal anti-inflammatory drugs (NSAIDs) are being reported with its diverse effect in the host resulting in ulcerations. Ulceration was induced orally using aspirin. Twenty-four male Wistar rats were used for this study (120-150g). Rats were divided into 6 groups with each group containing 4 rats. Rats were pre-treated orally with cimetidine, a reference drug. Group 1 rats orally received 1% gum acacia solution as the control group, Group 2 rats orally administered 25 mg/kg aspirin and served as the ulcerated, untreated group, rats in groups 3 and 4 were pre-treated orally with 200 mg/kg and 400 mg/kg respectively for 3 days while rats in groups 5 and 6 were pre-treated orally with 50 mg/kg cimetidine and 50 mg/kg catechin respectively for 3 days. The result of this study shows that the ulcerated, untreated rats showed increased concentrations of The result of this study shows that the ulcerated, untreated rats showed increased concentrations of acid output, pepsin activity with a concomitant decrease in pH values, and mucin content compared to control group but pre-treatment with different doses, cimetidine and catechin reversed these observations. Activities of superoxide oxidase were decreased in the ulcerated, untreated group with a concomitant increase in lipid peroxidation concentration but pre-treatment with different doses, cimetidine and catechin reversed these observations. In conclusion, the ethanoic extract of L. aestuans can be said to be used therapeutically agaisnt aspirin-induced gastric ulcer which is due to the presence of bioactive compounds in the plant.
 as an anti-ulcerogenic agent against aspirin-induced gastric ulcer which is due to the presence of phytochemicals in the plant.
 Keywords: Ulcerations, bioactive compounds, oxidative stress, superoxide dismutase, aspirin

Genome shuffling of Lactobacillus plantarum 163 enhanced antibacterial activity and usefulness in preserving orange juice.

Lactic acid bacteria have been used to inhibit the growth of spoilage bacteria in food and animal feeds. For instance, Lactobacillus plantarum 163 can inhibit efficiently the growth of both gram-positive and gram-negative bacteria. In our study, the antibacterial activity of L. plantarum 163 was further improved significantly by genome shuffling. The optimal conditions for protoplast formation and regeneration were 20 mg ml-1 lysozyme and 5 mg ml-1 mutanolysin for 30 min at 37°C using 0·5 mol l-1 sucrose as stabilizer. The protoplasts were inactivated under ultraviolet light for 120 s or heated at 58°C for 20 min. After two rounds of genome shuffling, the inhibitory activity of strain F2-14 was improved by 2·45- and 1·99-fold, respectively, as compared to their parent strains. The prepared antibacterial peptides supernatant (APS) was added to the orange juice to inhibit spores of Alicyclobacillus acidoterrestris (SAA) at 45 and 28°C. Results showed that the growth of A. acidoterrestris was significantly inhibited, and the decrease in total soluble solids, OD value and pH value was also delayed. After treatment with APS, the thermal sensitivity of spores was increased and its D value was reduced to 13·78, 3·87 and 1·47 min at 80, 90 and 95°C respectively.

Study on removing NO from simulated marine diesel engine exhaust gas using the novel composite system of Ozone-Na2SO3/(NH2)2CO

The pollutants from the marine exhaust gas seriously threaten air quality and human health. Wet absorption is one of the most efficient NOx control pathways. The strict emission control regulations require the wet NOx control technology to have high NOx removal efficiency and the nitrate concentration of the absorption solution to be below 60 mg/L. The novel system of ozone-Na2SO3/(NH2)2CO could not only make the NOx absorption efficiency and the amount of nitrate residue fully meet the regulations but also effectively reduce the (NH2)2CO consumption and the nitrite concentration. The final product of NO was mainly N2 instead of nitrate. The effects of O3 concentration, Na2SO3 concentration, (NH2)2CO concentration, O2 concentration, SO2 concentration, initial pH value, and temperature were thoroughly investigated. The experimental results showed that the NOx removal efficiency was mostly influenced by the O3 concentration, Na2SO3 concentration, and the initial pH value. Moreover, the nitrate concentration was mainly controlled by Na2SO3 concentration and initial pH value. While the nitrite concentration was governed by the (NH2)2CO concentration and initial pH value. The increase of O3 concentration and Na2SO3 concentration promote NOx absorption. Although the decrease of initial pH value resulted in a slight increase of nitrate, it greatly reduced the content of nitrite. Furthermore, the increase of Na2SO3 concentration helped to improve the NOx removal efficiency and inhibited the generation of nitrate. Initial pH value was the critical parameter for the NO absorption process. Ozone-Na2SO3/(NH2)2CO composite system showed great application potential in the field of marine wet NOx control technology.

Effects of Elemental Mercury Vapor Inhalation on Arterial Blood Gases, Lung Histology, and Interleukin-1 Expression in Pulmonary Tissues of Rats.

We investigated the effects of elemental mercury vapor inhalation on arterial blood gases (ABGs), lung histology, and interleukin-1 (IL-1) expression in pulmonary tissues in rats. A total of 42 Sprague Dawley rats were divided randomly into three groups. Rats in the first group were used as the control (CG). A short-term group (STG) and a long-term group (LTG) were exposed to 500 μg/m3 of mercury vapor 2 hrs/day for 21 days and 65 days, respectively. After exposure periods were completed, arterial blood samples were obtained, and ABGs were measured. Lung tissue sections were prepared for histology evaluation and immune-stained to detect IL-1 expression. There was a significant decrease in body weight in both STG (15%) and LTG (22%) compared with the CG. In the LTG, six out of 14 (43%) rats died, including two males and four females, while none of the rats in the STG died during the experiment. In both STG and LTG, a significant acid-base imbalance was characterized by a significant decrease in blood pH values and a significant increase in PCO2 values. Both PO2 and SpO2 blood values were significantly decreased in the STG and LTG, while no changes were observed in HCO3 values in all groups. Histological evaluation of lung tissues revealed severe lesions characterized by pulmonary emphysema and inflammatory cellular infiltrate. IL-1 expression in lung tissues was not significantly different between exposed rats and control subjects. These results indicate significant alterations in blood acid-base status characterized by severe respiratory acidosis with hypoxemia and no evidence of compensatory alkalosis in rats after exposure to short- and long-term elementary mercury vapor.

Effects of supercritical carbon dioxide under conditions potentially conducive to sterilization on physicochemical characteristics of a liposome formulation containing apigenin

In this work, the effects of four supercritical carbon dioxide (ScCO2) conditions potentially conductive to sterilization, on physicochemical characteristics of a liposome formulation containing apigenin (AG) were investigated. These conditions were: C1 (ScCO2/70 °C/150 bar/240 min), C2 (ScCO2/0.25% water/ 0.15% H2O2)/ 0.5% acetic anhydride/38 °C/85 bar/45 min), C3 (ScCO2/0.08% peracetic acid/35 °C/104 bar/180 min) and C4 (ScCO2/ 200 ppm H2O2/40 °C/270 bar/90 min). The results showed changes in color and a decrease in pH value of liposomes suspension after treatment with all tested conditions. Moreover, a decrease in liposome size with C1, C2 and C3 and an increase in the PDI with C1 and C3 were observed. For zeta potential, a decrease with C1, and an increase with C2 and C3 were found. Concerning the encapsulated AG, a moderate decrease, a strong decrease and a total disappearance were noted with conditions C1, C2 and C3 respectively.

​Effects of Starter Culture and Types of Bamboo Tubes on Microbiological and Shelf Life Characteristics of Buffalo Milk Banhor Chunga Doi- an Ethnic Product of India

Background: The present research was undertaken to study the effects of yoghurt culture and bamboo tubes on the microbiological and shelf life attributes of curd prepared from buffalo milk in bamboo tubes (popularly known as “Banhor Chunga Doi” in Assam) under room temperature. Methods: Banhor Chunga Doi was prepared using Jati and Jatie Makal bamboo tubes. Starter culture was added and the tubes were kept in ambient room temperature. The shelf-life of the set products was ascertained by objective assessment of pH, titratable acidity and microbial load. Result: Amongst the 4 treatment groups, the samples of B(JB) i.e., Banhor Chunga Doi prepared from boiled and cooled buffalo milk and stored in tubes of Jati bamboo at room temperature for 5d showed the highest pH value of 4.01±0.011 with a corresponding least lactic acid content of 1.21±0.005%. Amongst the 2 control and 4 treatment groups, the highest mean TVC of 8.69 log10cfu/g±0.001 was enumerated in the samples of SC (JB) which might be due to the addition of the starter culture at the dose level of approximately 6.86 log10cfu/g in the beginning of the production process. The starter culture added samples [SC (JB) and SC (JMB)] showed an increasing TVC up to 3rd day of storage. Thereafter, the TVC of these samples decreased on 5th day. The lowest mean TVC of 4.38±0.003 log10cfu/g was noted in the samples of B (JMB) which is due to the thermal destruction of the contaminating microbes during boiling of the milk sample. The samples of the buffalo milk Banhor Chunga Doi that were not inoculated with the starter culture exhibited an increasing TVC from 1st to the 5th d of storage at room temperature. Over the storage period, none of the Banhor Chunga Doi samples either from the control or the treatment groups were found to possess coliform organisms, Escherichia coli, Salmonella, Shigella, Staphylococcus aureus, yeast and moulds. The shelf life of the end product was found to be good for consumption upto 5 days with gradual decrease in pH values and concomitant increase in titratable acidity in all the treatment groups.

Metabolic Reprogramming and Immune Evasion in Nasopharyngeal Carcinoma.

Nasopharyngeal carcinoma (NPC) is a malignant tumor of the nasopharynx mainly characterized by geographic distribution and EBV infection. Metabolic reprogramming, one of the cancer hallmarks, has been frequently reported in NPCs to adapt to internal energy demands and external environmental pressures. Inevitably, the metabolic reprogramming within the tumor cell will lead to a decreased pH value and diverse nutritional supplements in the tumor-infiltrating micro-environment incorporating immune cells, fibroblasts, and endothelial cells. Accumulated evidence indicates that metabolic reprogramming derived from NPC cells may facilitate cancer progression and immunosuppression by cell-cell communications with their surrounding immune cells. This review presents the dysregulated metabolism processes, including glucose, fatty acid, amino acid, nucleotide metabolism, and their mutual interactions in NPC. Moreover, the potential connections between reprogrammed metabolism, tumor immunity, and associated therapy would be discussed in this review. Accordingly, the development of targets on the interactions between metabolic reprogramming and immune cells may provide assistances to overcome the current treatment resistance in NPC patients.

Electrochemical Corrosion Behavior of Laser Welded 2205 Duplex Stainless-Steel in Artificial Seawater Environment under Different Acidity and Alkalinity Conditions

The electrochemical corrosion behavior of laser welded 2205 duplex stainless-steel in artificial seawater environment (3.5% NaCl solutions) with different acidity and alkalinity conditions (different pH values) was investigated using different techniques. Namely, capacitance measurements (Mott–Schottky approach), electrochemical impedance spectroscopy and potentiodynamic polarization measurements. The formation of pitting corrosion on the exposure surfaces of the tested duplex stainless-steel samples was investigated and confirmed by characterizing the surface morphology using field emission scanning electron microscope (FE-SEM). Based on the obtained results, a proportional relation has been found between pH value of the solution medium and the generated film resistance due to the processes of charge transfer, which directly affecting the pitting formation and its specifications. Since the film layer composition created on the duplex stainless-steel surface is changes depending on the pH value, it was found that different bilayer structure type was generated according to the acidity or alkalinity level. The presented bilayer is almost composed from metal oxides, such as iron oxide and chromium oxide, as confirmed by Raman Spectroscopy technique. As the pits size and its quantity increased with decreasing pH value, it can be concluded that the corrosion resistance property of the laser welded 2205 duplex stainless-steel sample is improved on the alkalinity direction of the solution. Vice versa, higher acidic solution has more ability for corrosion.

Effects of Vanillic Acid on Dynamic Fermentation Parameter, Nitrogen Distribution, Bacterial Community, and Enzymatic Hydrolysis of Stylo Silage.

Vanillic acid (VA) is a phenolic acid derivative commonly found in plants and foods, with a pleasant creamy odor and pharmacologic activities, which is hypothesized to help improve silage fermentation. The silage profile of stylo silage ensiled with addition of VA was evaluated. The results showed that VA addition resulted in the decrease of pH value (5.22 vs. 4.33), dry matter loss (5.37 vs. 2.51% DM), and ammonia-N proportion (14.57 vs. 1.51% CP) of stylo silage as well as the increase of lactic acid concentration (0.51 vs. 1.17% DM), true protein proportion (51.18 vs. 58.47% CP), and saccharification yield (113.64 vs. 126.40 mg/g DM). Meanwhile, bacterial community of stylo silage was altered, where the relative abundance of Enterobacter, Clostridium, and Kosakonia decreased and that of Commensalibacter and Methylobacterium increased. In conclusion, it is suggested that VA could be used as a novel silage additive to improve silage fermentation and nutrient preservation of stylo silage.

Investigating the rus and petI operon expression patterns in exposed Acidithiobacillus ferrooxidans sp. FJ2 to different doses of gamma irradiation

The bioleaching process is developing as an economic and successful biotechnology method in the metallurgy industry. Acidithiobacillus ferrooxidans is one of the most important bacteria involved in uranium bioleaching which converts insoluble U4+ to soluble U6+ by oxidation of Fe2+ to Fe3+ using several periplasmic proteins encoded by the genes in rus and petI operons in its electron transport pathway. Accordingly, the purpose of this study was to consider the expression of these genes through exposed A. ferrooxidans sp. FJ2 to γ-ray in 17 different doses targeting uranium extraction yield.Acidithiobacillus ferrooxidans sp. FJ2 was irradiated by gamma rays at 25, 50, 75, 100, 150, 300, 450, 600, 750 Gy and 1, 2, 5, 10, 15, 20, 25 and 30 kGy doses. Moreover, the Eh value of 9k culture media was measured as special screening criteria to select the four treatments. The selected bacteria were cultured in 9k media, containing 50% uranium ore powder in the bioleaching process. Then, the value of pH & Eh of culture media, Fe2+ and uranium concentrations in 4, 8 and 13 day's period of incubation were measured. In followings, the expression levels of cyc1, cyc2, rus, coxB, petA, petB, petC and cycA genes at the end of each period were investigated by real-time PCR.Overall, all samples demonstrated a decrease in pH value and Fe2+ concentration and an increase in Eh value and U concentration in time intervals. The gamma irradiation in given doses raised the expression levels of all genes encoded in rus and petI operons, except petB gene during the bioleaching process, although, it had no effect either on the pH, Eh values or on Fe2+ and uranium concentrations.This result implies that during the oxidation of ferrous iron and formation of Jarosite sediment, the decreasing trend of pH and the increasing trend of Eh occurred in all samples. However, the differences in expression of the genes of rus and petI operons in the samples did not have an effect on uranium extraction.

Kinetic model development for α-amino ester hydrolase (AEH)-catalyzed synthesis of β-lactam antibiotics

α-Amino ester hydrolases (AEH) are a class of enzymes highly specific for catalyzing the synthesis and hydrolysis of amides and esters of α-amino acids. They are particularly promising catalyst candidates as an alternative to penicillin G acylase (PGA) for synthesis of a variety of β-lactam antibiotics, including cephalexin, cefadroxil, amoxicillin, and ampicillin. In this study, X. campestris pv. campestris AEH and two previously established quadruple variants designed for enhanced stability (N186D/A275P/V622I/E143G termed QVG and N186D/A275P/V622I/E143H termed QVH) were characterized in terms of their kinetic properties. AEH appears to have highest substrate specificity for cephalosporins, particularly cephalexin. The optimum pH value for activity was found to be between pH 6.5 – 6.75 for synthesis of amoxicillin, cephalexin, and cefadroxil, while synthesis selectivity consistently increased with decreasing pH value. Evidence for substrate inhibition preventing the β-lactam nucleus from binding and forming the corresponding amide is discussed. Time-course kinetic data across a wide range of substrate concentrations was found to corroborate the presence of substrate inhibition, and five possible kinetic models are derived to explain AEH-catalyzed cephalexin synthesis kinetic profiles. A best fit model that incorporates both competitive substrate inhibition and partial substrate inhibition was selected based on the Akaike Information Criterion (AIC) and quality of fit at high substrate concentration. Finally, progress of the synthesis of beta-lactams in a single CSTR was simulated using the best fit kinetic model and a Pareto optimal front was constructed for fractional yield, productivity, and substrate conversion to evaluate potential reactor configurations.

Relationship of soil pH value and soil Pb bio-availability and Pb enrichment in tea leaves.

Lead (Pb) is not an essential element for the growth of tea trees, but it is an important index for evaluating the quality and safety of tea. Lead is a sensitive metal to pH. Exploring the changing trend of soil Pb and enrichment coefficient of Pb in tea leaves affected by soil acidification is significant for tea planting and tea quality safety control. A percent of 37.57% of the 364 tea plantations in Anxi county of China showed soil acidification that is a soil pH value < 4.5. However, the total Pb content in the soil and Pb content of tea leaves met the requirements stipulated in China. The soil available Pb content and Pb content in tea leaves were both significantly negatively correlated with soil pH value, and increased with the decrease of soil pH value. The soil available Pb content had a significant positive correlation with soil total Pb content. However, the soil total Pb content had no significant correlation with soil pH value. Moreover, the soil Pb bio-availability coefficient and the Pb enrichment coefficient of tea leaves decreased with the increase of soil pH value. More than a third of tea plantations in Anxi county had been acidified. The decrease of pH value leads to an increase in the bio-availability coefficient of soil Pb content and the enrichment coefficient of Pb content in tea leaves. The lower soil pH value resulted in the increase of the absorption and accumulation of Pb by tea trees, thus an increase of Pb content in tea leaves. © 2021 Society of Chemical Industry.

Aplikasi aktivitas antioksidan tepung gathot (singkong terfermentasi) dalam edible film sosis ayam di suhu ruang

&lt;p class="MDPI17abstract"&gt;&lt;strong&gt;Objective: &lt;/strong&gt;The objective of this research is to examine the antioxidant properties of gathot and its potential as edible film.&lt;/p&gt;&lt;p class="MDPI17abstract"&gt;&lt;strong&gt;Methods: &lt;/strong&gt;The materials used were dry &lt;em&gt;gathot&lt;/em&gt;, carrageenan, and glycerol. The method was conducted experimentally, antioxidant activities test of &lt;em&gt;gathot&lt;/em&gt; flour were analyzed descriptively. Physicochemical test of the chicken sausage was analyzed quantitatively by RAL with a 2x5 factorial pattern. The first factor was the types of edible film (0.00 and 0.75%), and the second factor was storage time (0; 2; 4; 6; 8 days) with seven repetitions each variables. The quantitative data were processed by Minitab 19.0.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="MDPI17abstract"&gt;&lt;strong&gt;Results: &lt;/strong&gt;The results of the antioxidant test of &lt;em&gt;gathot&lt;/em&gt; flour were antioxidant activities of 26.174 ppm; scavenging ability of 49.37%; phenol of 4,852.84µg/g; flavonoids of 4,520.30µg/g. The chicken sausage for eight days at room temperature has a decrease in pH value, a* and b*, and an increase in TBA (Thiobarbituric Acid) value and water content.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="MDPI17abstract"&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;The antioxidant level of &lt;em&gt;gathot&lt;/em&gt; flour is classified as a weak antioxidant, the results in the application of &lt;em&gt;gathot&lt;/em&gt; flour edible film with a concentration of 0.75% were able to maintain the quality of chicken sausage until day six at room temperature storage (28 ºC).&lt;/p&gt;

A simple optical pH sensor based on pectin and Ruellia tuberosa L-derived anthocyanin for fish freshness monitoring.

A simple optical pH sensor using the active compound anthocyanin (ACN), derived Ruellia tuberosa L. flower immobilized in a pectin membrane matrix, was been fabricated and employed to monitor the freshness of tilapia fish at room temperature and 4 oC storage. The quantitative pH values were measured based on the UV-Vis spectroscopy absorbance.The optimum pectin weight and ACN concentrations were 0.1% and 0.025 mg/L. The sensor showed good sensitivity at 0.03 M phosphate buffer solution. The sensor's reproducibility was evaluated using 10 replicate sensors where a standard deviation of 0.045 or relative standard deviation of 9.15 was achieved. The sensor displayed an excellent response after 10 minutes of exposure, possessing a response stability for 10 consecutive days. The decrease in pH value of the Tilapia fish from 7.3 to 5 was observed in a 48 hour test, which can be used as the parameter when monitoring fish freshness.Overall, this reported optical pH sensor has a novelty as it could be used to monitor the rigor mortis phase of fish meat, which is useful in food industry.

Conversion equations between Olsen-P and other methods used to assess plant available soil phosphorus in Europe – A review

Plant available soil phosphorus contents are assessed by various different methods worldwide. The resulting country-specific methodology prohibits comparison or joint analysis of international data on yield response to soil P level. A change of the standard method would decrease comparability to older data, require new costly and time-consuming calibration and familiarization of advisory authorities and farmers. The use of conversion equations can allow the combination of data derived by different methods, but large differences between available equations question their reliability. The aim of this review is to provide a comprehensive overview of conversion options from P extracted by methods commonly used in Europe (acid ammonium acetate, acid ammonium acetate + EDTA, ammonium lactate, calcium acetate lactate, double lactate, H2O and Mehlich 3) to the widely used Olsen method. For a given method of soil P extraction, coefficients derived from different publications often vary by factors above two. Differences in coefficients can, at least to a certain degree, be attributed to variations in soil type, soil texture and especially pH range and carbonate contents of the soils of the according databases. In several studies, decreasing pH values increased Olsen-P values in relation to the other methods. Linear regressions are prone to bias by the right-skewed distribution of P values in most databases and therefore have to be handled with care on the lower end of the P level range. Even the option most appropriate for the soil and research purpose at hand can be a considerable source of error, therefore conversions should only be conducted if absolutely necessary.

A simple optical pH sensor based on pectin and Ruellia tuberosa L-derived anthocyanin for fish freshness monitoring

A simple optical pH sensor using the active compound anthocyanin (ACN), derived Ruellia tuberosa L. flower immobilized in a pectin membrane matrix, was been fabricated and employed to monitor the freshness of tilapia fish at room temperature and 4 oC storage. The quantitative pH values were measured based on the UV-Vis spectroscopy absorbance. The optimum pectin weight and ACN concentrations were 0.1% and 0.025 mg/L. The sensor showed good sensitivity at 0.03 M phosphate buffer solution. The sensor’s reproducibility was evaluated using 10 replicate sensors where a standard deviation of 0.045 or relative standard deviation of 9.15 was achieved. The sensor displayed an excellent response after 10 minutes of exposure, possessing a response stability for 10 consecutive days. The decrease in pH value of the Tilapia fish from 7.3 to 5 was observed in a 48 hour test, which can be used as the parameter when monitoring fish freshness. Overall, this reported optical pH sensor has a novelty as it could be used to monitor the rigor mortis phase of fish meat, which is useful in food industry.

Effect of water- and acid-pickling of aquaticplant biochar on the adsorption of Cd

To reveal the influencing factors and mechanism of adsorption of heavy metal Cd by biochar, different elution solvents (water and dilute acid solution) were used in this paper to elute the residual ash substances after pyrolysis of biochar, then the pH was regulated to investigate the adsorption effect of biochar on Cd in different treatment conditions. The precipitation experiments of Cd by biochar soaking and washing filtrate showed that the precipitation of root, stem and leaf of Acorus calamus L. contributed a great deal to the heavy metal removal system, which accounting for 81%, 77% and 98%, respectively, and the adsorption effect of biochar of roots, stems and leaves of Acorus calamus L. on Cd was slightly increased after washing. The adsorption experiment of biochar pickling on heavy metals showed that the adsorption effect of biochar on heavy metals Cd decreased greatly after pickling, which may be due to the removal of most of the minerals on the surface of biochar after pickling and the decrease of pH value of biochar. This work can provide insights into the use of biochar to control Cd.

Effect of pH on Effective Slip Length and Surface Charge at Solid-Oil Interfaces of Roughness-Induced Surfaces.

Featured Application Drag reduction in many applications of micro-/nano-fluidic channel. In the development of micro/nano fluid control systems, fluid resistance has always been one of the key factors restricting its development. According to previous studies, it is found that the boundary slip effect of the solid-liquid interface can effectively reduce the resistance of the microfluid and improve the transport efficiency of the microfluid. The boundary slip length is mainly affected by surface wettability, roughness, and surface charge density. Among them, the influence mechanism of surface charge density on the boundary slip is the most complicated, and there is a lack of relevant research, and further investigation is needed. In this paper, we present research on quantification of effective slip length and surface charge density, where the roughness effect is considered. The electrostatic and hydrodynamic force data obtained from atomic force microscopy (AFM) measurements were fitted and processed for comparative analysis. We obtained the variation of surface charge density and effective slip length when different oleophobic surface samples were immersed in ethylene glycol with different pH values. The effect of pH on the surface charge density and effective slip length was investigated by their variations. The mechanism of the effect of pH on the surface charge density was discussed. The experimental results show that in the ethylene glycol solution, no matter whether the pH value of the solution increases or decreases, the charge density of the surface with the same properties decreases, and the effective boundary slip length also shows a downward trend. In deionized water, the surface charge density and effective boundary slip length decreases with the decrease of PH value.

Application of Elemental Geochemistry in High-Frequency Sequence—Stratigraphic Analysis of Lacustrine Shale

The successful development of shale gas and oil in North America has created considerable interest in shale. The analysis of genetic types, the sedimentary environment, and the mudstone development mechanism within sequences is critical for evaluating shale gas and oil exploration prospects, exploration favorable zones, and resource potential. This study focused on the shale of Shahejie Formation in Dongying Depression of Bohai Bay Basin. Shale lithofacies division, geochemical analysis, and well-log analysis were performed for a sedimentary environment and its related elemental response characteristics’ identification. Based on the results, we concluded that the sedimentary environment of the lake basin evolved from the saltwater lake to the ambiguous lake and then the open lake to the delta. In response, we observed gradually decreasing Sr/Ba and Ca/Mg ratios and increasing Rb/Ca and Fe/Mn ratios during the whole process during the reduction of the salinity and the decrease in PH value and sediments’ transport distance. The relationship between ratio elements and high-frequency sequences was initially established within the shale strata. Our results show that ratios of Sr/Ba and Ca/Mg ratios near the sequence boundary are relatively low, and ratios of Fe/Mn and Rb/Ca are relatively high, while ratios of Sr/Ba and Ca/Mg near the flooding surface are relatively high, and ratios of Fe/Mn and Rb/Ca are relatively low. Those features can be used as a marker for high-frequency sequence division of shale strata. Our results provided a new theoretical basis and technical method for shale gas and oil exploration and development.

Investigation of solution acidity influence on the morphological structure and physical and mechanical properties of particle-reinforced tungsten alloys

Yttria-stabilized zirconia particle–reinforced tungsten alloys were fabricated by using azeotropic distillation process coupled with powder metallurgy techniques. The influence of pH value of the original solution on the precursor powders’ morphology and wear and mechanical properties of alloys was deeply studied. It showed that the precursor powder synthesized under solution with pH of 2 possesses finer particle size. The grain sizes of tungsten reinforced alloys obtained with different pH values vary from 2 to 6 μm, extremely smaller than that of pure tungsten. When pH value increases from 2 to 8, more and more bonding zirconia particles are obtained. The reinforced tungsten alloy prepared based on the solution of pH equal to 2 has better morphological and mechanical properties than the other two alloys prepared based on the solution of pH values of 5 and 8, respectively. The wear resistance of the reinforced tungsten alloy increases firstly and then decreases with the doping amount of zirconia particles. It is confirmed that the pH 2 value and chemical composition of the tungsten alloy with 3.0 wt. % Zr(Y)O2 exhibit the best wear resistance. The mechanical properties of the particle-reinforced tungsten alloy are improved with the decrease of pH value. The ultimate compressive strength and ultimate strain values of pH 2 reach to 1009 MPa and 0.23, respectively. The evolution of the relative density and associated porosity increases with the pH value. The abrasion mechanism was analyzed in detail.