Titration Test Research Articles

Surface Modification of Multi-Walled Carbon Nanotubes with Polysaccharides

Multi-walled carbon nanotubes (MWCNTs) are known as efficient drug carriers. To improve their interaction with other materials, surface modification of MWCNTs is necessary. In this work, MWCNTs were functionalized with acid and polysaccharides (chitosan and gelatin). The functionalization process was done via modification with acid solutions of nitric acid, sulfuric acid, and a mixture of nitric acid-sulfuric acid first, followed by functionalization with chitosan and gelatin. To achieve the optimum condition of MWCNTs functionalization, the reaction time, temperature, and acid ratio were varied. Furthermore, the effect of chitosan and gelatin addition into MWCNTs was studied at various mass ratios. The synthesized materials were characterized by Fourier transform infrared spectrophotometer, Boehm titration, and dispersion test. The Boehm titration results showed that the acid functional groups had been attached successfully to MWCNTs surface. The amount of acid functional groups increased along with reaction time. The highest amount of acidic group obtained from the data was 2.33 mmol/g. It was achieved when MWCNTs reacted with nitric acid for 24 hours. Temperature and acid ratio variations on the MWCNTs functionalization did not provide significant results. From the FTIR data, sharp peaks at 3480 cm-1 and 1040 cm-1 indicates a -CONH bond, which shows that chitosan and gelatin have been successfully grafted onto MWCNTs surface via an amide linkage. Moreover, the dispersion test showed that the functionalized materials were stable for 48 hours.

A New Trial to Measure ABO Antibodies Using Complement-Dependent Cytotoxicity.

Background and objectives: The ABO antibody (Ab) titration tests are used in monitoring in ABO-incompatible (ABOi) solid organ transplantation (SOT). However, currently developed ABO Ab tests show Ab binding reactions. This study attempted to measure ABO Ab level using complement-dependent cytotoxicity (CDC). Materials and methods: We studied 93 blood group O serum samples from patients who underwent ABOi SOT from January 2019 to May 2021. Patients’ sera were incubated with A1 or B cells and added to a human complement solution. Supernatants were collected after centrifugation, and free hemoglobin (Hb) was measured by spectrophotometry. We converted plasma Hb value to hemolysis (%), which were compared with ABO Ab titer. Results: We found a mild correlation between hemolysis and ABO Ab titers. In simple regression analysis, the correlation coefficients were within 0.3660–0.4968 (p < 0.0001) before transplantation. In multiple linear regression analysis, anti-A hemolysis (%) was higher in immunoglobulin M (IgM) (β = 12.9) than in immunoglobulin G (IgG) (β = −3.4) (R2 = 0.5216). Anti-B hemolysis was higher in IgM (β = 8.7) than in IgG (β = 0.0) (R2 = 0.5114). There was a large variation in hemolysis within the same Ab titer. Conclusions: CDC can be used in a new trial for ABO Ab measurement. Furthermore, IgM rather than IgG seems to play a significant role in vivo activity, consistent with previous knowledge. Thus, this study may help in the development of the ABO Ab titration supplement test for post-transplant treatment policy establishment and pre-transplant desensitization.

The influence of mixing technology on the uniformity and strength of cement stabilized macadam mixture

A comparison between the two strategies: secondary traditional mixing technology and secondary vibratory mixing technology is proposed based on aggregate sieving, cement EDTA titration and unconfined compressive strength tests to explore the influence of the uniformity and strength of cement stabilized macadam mixture in the paper. The results show that when the secondary vibratory mixing technology is adopted: (1) the standard deviations and coefficients of variation of the passing rates of key sieves of 19 mm, 13.2 mm, 9.5 mm, 4.75 mm and the cement dosage titration results decrease significantly, and the mixing uniformity of the mixture is significantly improved; (2) the 7-day and 28-day unconfined compressive strengths of the mixtures are significantly improved while the strength standard deviations and coefficients of variation are reduced, with an obvious trend along with the extension of the curing time (within 28 days).

Risks related to a possible reduction of the waiting period for dogs after rabies antibody titration to 30 days compared with 90 days of the current EU legislative regime.

EFSA received a mandate from the European Commission to assess the risks related to a possible reduction of the waiting period after rabies antibody titration test to 30 days compared with 90 days of the current EU legislation, for dogs moving from certain non‐EU countries to the EU. This Scientific Report assessed the probability of introduction of rabies into the EU through commercial and non‐commercial movements of vaccinated dogs with a positive titration test (≥ 0.5 IU/mL) if the waiting period decreases from 90 to 30 days. Assuming that all the legal requirements are complied with, the risk of transmission of rabies through the movement of a vaccinated dog is related to the risk of introducing an animal incubating rabies that was infected before the day of vaccination or shortly after vaccination but before the development of immunity (21 days post‐vaccination). Using published data on the incubation period for experimental and field cases in dogs and considering the rabies incidence data in certain countries, the aggregated probability for the annual introduction of rabies through dogs was assessed. Considering the uncertainty related to the duration of the incubation period, the number of imported dogs, and the disease incidence in some countries it was concluded with a 95% certainty that the maximum number of rabies‐infected imported dogs complying with the regulations in a 20‐year period could increase from 5 to 20 when decreasing the waiting period from 90 to 30 days. Nevertheless, the potential impact of even a small increase in probability means the risk is increased for a region like the EU where rabies has long been a focus for eradication, to protect human and animal health.

Community Access to Adequately Iodized Salt in Rural Amhara, Ethiopia

ObjectivesTo assess community access to adequately iodized salt in rural Amhara, Ethiopia. MethodsWe collected market and household salt samples from December 2020-January 2021 in West Gojam and South Gondar, Amhara, Ethiopia. A total of 24 salt samples were collected from markets randomly chosen in proximity to six rural health centers prior to the Enhancing Nutrition and Antenatal infection Treatment (ENAT study). 12 salt samples were unpackaged salt sold in open markets and 12 samples were packed samples procured from local shops. Household salt samples were also collected among mothers consecutively enrolled in the ENAT study over a one-month period at baseline. Quantitative assessment of iodine content was performed by iodometric titration at a central referral laboratory. In addition, a rapid qualitative salt assessment (MBI rapid test, Chennai, India) was done for 238 randomly selected households in walking proximity to the study health centers. The MBI test used rapid qualitative colorimetric methods, to test for adequacy of iodization (no color change: 0 ppm, light purple: <15 ppm, dark purple >15 ppm). ResultsThe median iodine titration level for local market salt was 37.1 ppm (range: 14.3–116.4). Fifteen (62.5%) samples were at recommended levels (15–40 ppm), 8(33.3%) were >40 ppm and one sample <15 ppm. The median iodine titration test for household samples was 42.7 ppm (range: 10.1–89.8); with 19 (33.3%) samples at the recommended levels, 33(57.9%) >40 ppm, and 5(8.8%) of samples <15 ppm. On the other hand, among the community based, household-level samples (n = 238) tested by MBI rapid kits, 8(3.4%) had no iodization, 116 (48.7%) were inadequately iodized (<15 ppm), and 114(47.9%) were >15 ppm. ConclusionsThere is heterogeneity in the level of iodization in salts available in the markets in Amhara, with the majority of samples were iodized >15 ppm; though almost 40% were above WHO recommended levels. At the household level, iodine content in nearly half of community-based samples were inadequate. Standardization of quality of market salt and optimal storage of iodized salt to prevent degradation at the household level are needed. Funding SourcesBill & Melinda Gates Foundation.

Use of Equine Herpesvirus 1 glycoprotein pseudotyped lentiviral particles for the development of serological tests and assessment of lyophilisation for transport and storage

Equine herpesviruses (EHVs) are enveloped DNA viruses predominantly infecting members of the Equidae family. EHVs primarily cause respiratory disease, however EHV-1 can produce cases of a neurological disease, abortion and neonatal death. Thus, these viruses represent a welfare issue for the equine industry and scientific focus for researchers. EHV-1 exhibits a complex array of 12 glycoproteins on its surface envelope, but it is unclear precisely which are important for virus cell entry and the role of each in host immune response. In order to investigate the contribution of these glycoproteins, pseudotype viruses (PVs) could provide a useful study tool. We have successfully generated functional EHV-1 pseudotyped lentiviruses bearing four glycoproteins, gB, gD, gH and gL (sequences derived from an aborted foetus during a large EHV1 outbreak strain in Normandy, France). PVs were employed in a pseudotype virus neutralisation test (PVNT) to measure levels of specific neutralising antibodies serum samples (n=52) taken longitudinally from experimentally infected ponies, compared with uninfected controls. PVs routinely require -80oC for long term storage and a dry ice cold-chain during transport which can impede dissemination and utilisation in other laboratories. Consequently, we further investigated whether freeze-drying (lyophilisation) of EHV-1 PV could address this issue. PVs were lyophilised and pellets either reconstituted immediately or stored under various temperature conditions, sampling at different timepoints. The recovery and functionality of these lyophilised PVs was compared with standard frozen aliquots in titration and neutralisation tests.

Exploration of Carbon Dioxide Curing of Low Reactive Alkali-Activated Fly Ash.

In this paper, the effect of carbon curing procedure on low reactive fly ash alkali-activated pastes was investigated. Specimens were cured with pure carbon dioxide (CO2) gas for different curing times under 4 bar pressure. Chemical and physical characteristics of the geopolymer pastes were obtained from mass monitoring, titration test, XRD, FTIR and TGA-DTG analyses. Regarding the test results, after three days of CO2 curing, the highest CO2 uptake was obtained at 4.8 wt% of fly ash precursor, with carbon sequestration efficiency at 22.6%. The ratio of carbon dioxide absorbed as efflorescence to the total absorbed CO2 was measured. The results show that at early age, almost 50% of carbonated products appeared as efflorescence; however, by increasing the curing time, and after 3 days of curing, about 80% of carbon dioxide was stored in the matrix. It was found that, in all cases, carbonation curing was detrimental to the geopolymerization process due to a high amount of efflorescence and led to a reduction in the compressive strength. At 24 h and 3 days, the specimens showed a lower reduction in compressive strength in comparison to CO2 samples cured at 3 h, 6 h and 12 h. Regarding the XRD results, calcite was detected in the 24 h and 3 days specimens, which contributes to lower pore sizes due to a higher molar volume and production of silica gel that might participate in the polymerization processes and results in densified microstructures.

Mechanism of Filtration Behaviors of Cement-Based Grout in Saturated Sand under Different Grouting Conditions

Cement-based grout has been widely used in various civil engineering applications. However, the filtration behaviors of it when grouting the porous geological masses vary a lot under different grouting conditions, which significantly influences its penetration and the enhancement effect. The purpose of this work was to better understand the filtration of cement-based grout in porous sand by conducting a series of visualized laboratory tests and EDTA titration tests. The experimental results show that the cement filtration, including the penetration, retention, and formation of cement filter cake above the grouting body, is collectively influenced by different grouting factors. With the increase of the soil samples’ pore size and the cement slurry’s water-cement ratio, the penetrated distance and amount of cement in sand increase. However, the penetration does not increase monotonically with the grouting pressure. Too excessive grouting pressure (e.g., 300 kPa in this study) accelerates the formation of cement filter cake and thus stops the subsequent cement infiltration. The mechanisms of different filtration behaviors were explained from microscopic particle clogging in the pore throat of the porous media. Furthermore, the reduced permeability of the sand column with the retained cement due to filtration was discussed, and the dewatering phenomenon of the cement slurry after filter cake formation was first revealed.

Cats with Genetic Variants of AGXT2 Respond Differently to a Dietary Intervention Known to Reduce the Risk of Calcium Oxalate Stone Formation.

This study was completed to evaluate a genotype-specific nutritional intervention for reducing the risk of calcium oxalate stone formation. Serum metabolomic profiles and genotypes of 445 cats in the colony at Hill’s Pet Nutrition, Inc (Topeka, KS, USA)were assessed in a genome-wide association study, and revealed an association between genetic variants of alanine-glyoxylate aminotransferase 2 (AGXT2) and 2-oxoarginine. The most significant single nucleotide polymorphisms (SNP) associated with 2-oxoarginine was at position chrA1:212069607, [G/A] (p < 3.687 × 10−17). This SNP explained approximately 15% of the variance in 2-oxoarginine concentrations. The distribution of genotype frequencies was 0.07 AA, 0.39 AG, and 0.54 GG, with a mean relative 2-oxoarginine concentration for each genotype of 0.45 AA, 0.92 AG, and 1.27 GG, indicating a subtractive effect of the minor allele (A). Serum concentrations of two AGXT2 substrates, symmetric/asymmetric dimethylarginines (SDMA/ADMA) and β-aminoisobutyrate (BAIB) were also strongly associated with SNP chrA1:212069607 (p < 1.43 × 10−12 and p < 2.30 × 10−14, respectively). These two AGXT2 substrates were increased with the minor allele (A), indicating that the variant of the AGXT2 gene results in decreased aminotransferase activity. Additionally, the lifetime history of stone incidence showed that cats with the AA variant of AGXT2 SNP had a 2.515× increased incidence of stones compared with cats having the GG variant (p = 0.019). In a subsequent study assessing AGXT2 genotypes, cats (n = 10 GG, 4 AG, 9 AA) were fed control or test food (containing betaine at 0.500%, and the botanicals green tea, fenugreek and tulsi at 0.25, 0.025, and 0.0015%, respectively) in a cross-over study design. Stone risk analysis was conducted on urine samples after feeding control or test food for 28 days each. A calcium oxalate titration test (COT) was performed to assess the amount of added Ox−2 (per L) required to initiate calcium oxalate crystal formation. Cats with the GG variant of the AGXT2 SNP required more added oxalate to initiate urine crystal formation after consuming test food compared with control food, indicating a decreased risk of oxalate crystal formation in GG cats. In addition, urine oxalate concentrations showed an overall effect of test food independent of genotype (p = 0.0009), which resulted in lower oxalate concentrations after consuming test food compared with control food. These data indicate that cats with the GG-specific variant of AGXT2 should benefit from a reduced risk of calcium oxalate stone formation after consuming a betaine and botanical dietary enhancement.

Electroextraction of neodymium from LiCl-KCl melt using binary liquid Ga–Al cathode

The electrochemical behaviour of Nd(III) ion was investigated on inert W, active Ga and Ga–Al cathodes. It is established that the reduction of Nd(III) ion on the inert electrode is a consecutive two-step process while that on the active electrodes is a one-step process. The apparent standard potential of the Nd(III)/Nd redox couple at different temperatures was determined by open-circuit chronopotentiometry and semi-differential method, and the relationship between temperature and apparent standard potential was further discussed. The thermodynamic properties of Nd in Ga and Ga–Al electrodes such as activity coefficient and activity were evaluated via intermittent coulomb titration and temperature dependence test, and the effect of temperature on activity coefficient was verified. Finally, Nd was successfully extracted in form of alloy from molten salt by galvanostatic electrolysis, in which the current efficiency of 91.7% for the electroextraction indicates that the binary liquid Ga–Al electrode has favorable performance.

Comparison of Anti-D Titration Testing by Automated Column Agglutination Technology on Glass-Beads and Standard Tube Method

Comparison of Anti-D Titration Testing by Automated Column Agglutination Technology on Glass-Beads and Standard Tube Method

Determination of ABO antibody titre and haemolysin test of group O whole blood used for exchanged transfusion in a teaching hospital

Background: Group O blood donor is more readily available and is frequently used as a universal red cell donor and emergency O whole blood (EM O) for exchange transfusion in neonates. Sera from group O donors contains two separable haemolysin antibodies, anti-A and anti-B, and a cross-reacting antibody called anti-A, B (mostly IgG). The presence of haemolysins in the donors may lead to haemolysis in the recipients. Objectives: This study aims to determine the prevalence of anti-A and anti B haemolysins and titer among group O donors that we screened for emergency group O (EM O) whole blood Methodology: A cross sectional study was done to determine the prevalence of anti-A and anti B haemolysin and titer among group O blood donors screened for EM O whole blood for exchange transfusion in neonates at a teaching hospital from January to December 2018. Samples of 350 voluntary group O regular donors were selected for ABO antibodies titration and haemolysin test using the conventional tube technique at room temperature. Donors were screened for titer of 1:50 and 1:100 only. ABO antibody titer of ≥1:100 was considered as a high titer and not suitable for exchange transfusion. Titer of ≤1:50 were labeled as EM O whole blood and will be suitable for exchange transfusion. Results: A total of 350 group O blood donors were screened for the anti A and anti B haemolysin and titer. The majority of blood group O donors were male (n=215, 61%) and were age from 18-30 years old (51%). Malay was the predominant group (83%). About 52.9% of the donors were low titer (≤1:50), and 47.1% were high titer (≥1:100). Low titer was seen predominantly among male donors (61.8%). The prevalence of haemolysins in group O donors was 5.4% (n=19). Anti A and anti B haemolysins were seen in 0.57% and 2.28% of the donors, respectively, while donors having both A and B haemolysins in their sera was 2.57%. Conclusion: Prevalence of anti-A and anti-B haemolysins were low among group O blood donors. However, a significant percentage of group O donors have high titer of anti-A or anti-B. Therefore, despite the labour intensiveness of haemolysis titration technique and the frequent transfusion of group O blood for exchange transfusion, there is the need to routinely screen our donors for haemolysins in order to identify those posing the greatest risk to recipients. Bangladesh Journal of Medical Science Vol. 21 No. 02 April’22 Page : 368-372

Sewage-sludge derived activated carbon impregnated with polysulfide-sulfidated nZVI：A promising material for Cr(Ⅵ) reductive stabilization

This study aims to examine the reductive performance of a sulfidated iron-carbon composite synthesized using a sewage sludge from a typical biological wastewater treatment process. Sewage sludge was first carbonized under optimal conditions to prepare activated carbon (AC), followed by sequential treatment with nZVI and polysulfide to synthesize the iron-carbon composite S-nZVI/AC. Polysulfide was used to sulfurize nZVI due to its unique properties in stability, persistence and safety. Boehm titration and BET test showed that AC carried both acidic and basic sites in concentrations of 1.04 and 0.81 mmol/g per gram of material. The unmodified AC served mainly as a carrier to disperse nZVI grains from aggregation, although it also possessed a limited capacity of 3.5 mg/g for Cr(VI) sorption at neutral pH. Functionalized AC with nZVI boosted its capacity to about 29 times, while further treatment with polysulfide could further expand the material’s capacity by 36% to 136.0 mg/g. Sulfurizing the material with polysulfide also raised its reactivity as revealed by the kinetic experiments. Material characterizations suggested that multiple reductive species from S-nZVI/AC, including S(-Ⅱ) and Fe(Ⅱ) dissociated from FeS, Sx2-, and Fe0, might have participated in immobilizing Cr(VI). Specifically, S(-Ⅱ) and Sx2- were oxidized to SO42-, S2O32-, and S0, in decreasing order of concentration as inferred from XPS analysis.

Synthesis of a granular composite based on polyvinyl alcohol-Fe:Ce bimetallic oxide particles for the selective adsorption of As(V) from water

In this study, Fe:Ce bimetallic oxide particles (BOP) were immobilized in poly(vinyl) alcohol (PVA) hydrogel, aiming to engineer a granular material that preserves the adsorptive properties of BOP powder, allowing their use in conventional water treatment systems. Through a detailed evaluation of the synthesis conditions, we were able to produce a composite (PVA/BOP) with excellent physicochemical properties, while retaining up to 100% of the BOP arsenic adsorption capacity, even at ppb of As(V) concentrations. The composites were characterized by SEM, N2 physisorption, FT-IR, potentiometric titration, and compression test. Also, adsorption experiments including isotherms, kinetics, pH effect and selectivity were performed. The inclusion of BOP in the PVA hydrogel improved the mechanical properties of the hydrogel, increasing the elastic limit from 60% for PVA to 90% for the composite, making it suitable for packed bed systems. The BOP particles showed a uniform dispersion in the composite as evidenced by SEM. The surface area of the composite reached 10 m2/g and has an acidic surface (pHpzc of 4.1). The FTIR analyses allowed us to demonstrate the interactions of BOP with PVA, and to propose the arsenic adsorption mechanism. The dry composite labeled as C7P60 showed excellent arsenic removal: adsorption capacity of 77.62 mg/g measured at 0.8 mg As/L and pH 7; adsorption kinetics of 1.69 mg As(V)/min·g reaching equilibrium in less than 30 min; and a high affinity for arsenic in presence of competing anions, including F−, Cl−, HCO3−, NO3−, SO42− and H2PO4−. The results reported herein suggest that this granular composite PVA/BOP can be an excellent candidate to address arsenic water contamination problems.

The Positive Airway Pressure Therapy Compliance In Mild OSAS

Introduction: This study is designed to determine the factors for predicting the PAP compliance in mild obstructive sleep apnea syndrome (OSAS) for improving the cost-effectiveness in the treatment choices of these patients.&#x0D; Method: The study group comprises 27 mild OSAS patients who underwent automatic positive airway pressure (APAP) titration between July 2016 and December 2017. Demographic, clinic and polysomnographic characteristics of the patients were retrospectively evaluated. Compliance with PAP treatment was defined as the usage of 5 nights/week and 4 hours/night at least. Data of compliant patients were statistically compared with non-compliant patients.&#x0D; Results: Most of the patients (23 patients, 85,2%) were prescribed APAP devices. Acceptable compliance at the end of the first year of therapy was achieved by 11 patients (40,2%) whereas 8 patients used PAP device 2 months at most (29,6%) The remaining 8 patients had not taken the device at all and were considered as non-adherent to PAP treatment (29,6%). The nonadherent/non-compliant group showed statistically the same demographic, clinic, and polysomnographic characteristics when compared to the compliant group. The level of maximum pressure during the titration test was lower in the compliant group (p=0,040). &#x0D; Conclusion: The sleep-related symptoms, scores of ESS or polysomnographic parameters can not be used to predict compliance for mild OSAS. The patients with mild OSAS, especially the ones who reach higher maximum pressure on titration test, must be followed up closely during the first 2 months of PAP treatment to detect nonadherence/non-compliance earlier.

Improving interfacial stability by in situ protective layer formation in 4.2V poly(ethylene oxide) based solid state lithium batteries

The poly(ethylene oxide) based composite solid electrolyte(PEO-CSE) is an effective solution for developing high-performance solid-state lithium battery. However, the poly(ethlene oxide)(PEO) based solid-state lithium battery using 4.0 V cathode suffers from severe interfacial instability problems. In this work, we add additive lithium difluorophosphate(LiPO2F2) into the PEO-CSE to form a stable and low resistance interphase at the cathode/electrolyte interface during charge/discharge process. The electrochemical stability window of PEO-CSE increases to ∼5.0 V. Besides, the electrochemical performance of PEO based solid-state lithium battery with LiCoO2 as cathode is excellent. The discharge capacity of LiCoO2/Li cell with LiPO2F2 reaches 108.5 mAh g−1 at 1.0C. In contrast, the discharge capacity that without LiPO2F2 is only 60.0 mAh g−1. Meanwhile, the PEO-CSE with LiPO2F2 cell delivers stable cycle performance at 4.2 V. The capacity retention maintains 88.5% compared with 16.1%(without LiPO2F2) after 100 cycles. Furthermore, it's still maintains 83.3% after 150 cycles. In addition, the cathode/electrolyte interface is analyzed by transmission electron microscope(TEM) and X-ray photoelectron spectroscopy(XPS). Galvanostatic intermittent titration test(GITT) is used to analyze the dynamic diffusion performance. This strategy provides a simple and effective way to improve the high voltage stability of the cathode/electrolyte interface.

Characteristics of Obstructive Sleep Apnea Patients With Hypertension and Factors Associated With Autotitration Acceptance.

In order to explore the characteristics and treatment status of obstructive sleep apnea (OSA) patients with hypertension, a retrospective study was conducted on 306 patients admitted from October 2018 to December 2019. According to the apnea hypopnea index (AHI), OSA patients with hypertension were divided into three groups. 69 cases were mild OSA (5 ≤ AHI < 15), 86 cases were moderate (15 ≤ AHI < 30), and 151 cases were severe (AHI ≥ 30). Compared with patients in the mild and moderate groups, the severe group had more male patients, with higher body mass index (BMI) and non-rapid eye movement stage 1 accounted for total sleep time (N1%), and lower non-rapid eye movement stage 2 accounted for total sleep time (N2%), average and minimum blood oxygen. Among all the patients, those who underwent the titration test accounted for 20.6% (63/306). Multivariate analysis showed that sleep efficiency (p < 0.001) and AHI (p < 0.001) were independent factors for patients to accept titration test. OSA patients with hypertension had a low acceptance of titration therapy. These people with higher sleep efficiency and AHI were more likely to receive autotitration.

Study of Parameters Affecting the Aging of Transformer Oil

An electricity board acquires several transformers from a manufacturer in a belief that their advertised lifetime of the transformer thus purchased is true. However, they don’t take in the case of negligence in maintenance of transformer, which is a strenuous job. The advertised thirty-year lifetime is reduced to a mere two-year lifetime, mainly because of the degradation of the insulation medium (Transformer oil), thus increasing losses in the transformer and decreasing its efficiency. The degradation of transformer oil leads to safety hazards like transformer bursting, consequently forcing the electricity board to replace the transformer, thus incurring huge amount of costs. This is the most relatable problem faced by the electricity board in every state. This research work aims at listing out various properties of transformer oil and ascertaining major impurities in a transformer oil by testing it using various techniques. The proposed work deals with long term observation and analysis of transformer oil to determine its degradation rate. Breakdown voltage, Moisture content, Resistivity, Acidity, Furan Analysis and Dissolved Gas Analysis were done using Mushroom electrodes, Karl Fischer Titration test, Tan delta test, Potassium Hydroxide Titration, High performance liquid chromatography, and dissolved gas analyzer respectively. The results reveal that, deviation of Breakdown Voltage, Moisture content, and 2-Furaldehyde (1197ppb) from the permissible limits can indicate the aging of the transformer.

Reusing Flowback and Produced Water with Different Salinity to Prepare Guar Fracturing Fluid

Economical and environmental concerns have forced the oil and gas industry to consider reusing flowback and produced water for fracturing operations. The major challenge is that the high-salinity of flowback water usually prevents its compatibility with several fracturing fluid additives. In this paper, the authors explored an economic and effective method to prepare guar fracturing fluids with different salinity waters. The main research idea was to use chelating agents to mask metal ions, such as calcium and magnesium, that are harmful to crosslinking. Firstly, a complexometric titration test was conducted to measure the chelating ability of three chelating agents. Secondly, through viscosity, crosslinking, and hanging tests, it was verified that the complex masking method could cope with the problem of high-valence metal ions affecting crosslinking. Thirdly, the preferred chelating agent was mixed with several other additives, including thickeners, crosslinkers, and pH regulators, to prepare the novel guar fracturing fluid. The comprehensive performances of the novel fluid system were tested such as temperature and shear resistance, friction reduction, gel-breaking performance, and core damage rate. The results show that the organophosphate chelating agent (i.e., CA-5) had the greatest ability to chelate calcium and magnesium ions. There was a good linear relationship between the dosage of CA-5 and the total molar concentration of calcium and magnesium ions in brine water. The main mechanism was that the chelating agent formed a complex with calcium and magnesium ions at a chelation ratio of 1:5. The test results of the comprehensive performance evaluation indicate that the prepared guar fracturing fluid met the requirements for field application, and the lower the salinity of the flowback water, the more it is economical and effective.

Synthesis, rheological characterization, and proposed application of pre‐polyglycerol sebacate as ultrasound contrast agent based on theoretical estimation

AbstractElastomers are employed in the field of acoustics as sound enhancers and making tissue‐mimicking phantoms for ultrasound imaging due to their good viscoelastic properties. Polyglycerol sebacate (PGS) is a relatively new biocompatible, biodegradable elastomer with low elastic modulus prepared via two‐step melt condensation reaction. The first step yields a soluble pre‐polymer while the second results in a cured insoluble tough elastomer. The elasticity of polymer is dependent upon curing time. Attractive aspects of pre‐PGS to be used as ultrasound contrast agent lie in its excellent viscoelastic properties, that is, low elastic modulus, near to lipids. This can give it acoustic properties of lipid microbubbles while keeping a stable response of polymeric microbubbles. In this study, pre‐PGS was synthesized via the melt‐condensation method and characterized by FTIR, NMR, TGA, melt flow index, contact angle, titration, and uniaxial compressive testing. Viscosity was measured by the Ostwald technique. These viscoelastic measurements were used to predict the acoustic response of pre‐PGS shell‐based microbubbles by running equations in MATLAB. Pre‐PGS showed an elastic modulus of 1.26 MPa and thermal stability up to 100°C. PGS showed much more elasticity than commercially available Sonovue ultrasound contrast agent, also it has low viscosity (0.016 Pa s) and density (1186 kg/m), due to which it has a low damping coefficient (4.32 × 106) compared to Sonovue (7.63 × 107), giving better oscillations in an acoustic field with higher scattering cross‐sectional area than standard Sonovue microbubbles. Based on these simulations pre‐PGS with 50%–60% degree of esterification showed excellent viscoelastic properties which make it an ideal material for microbubble ultrasound contrast agent.