Method For Measurement Of Concentration Research Articles

Trial applications at gymnasiums of in-situ sound absorption measurement method by ensemble averaging technique

The authors have been published a series of papers on a measurement method for sound absorption characteristics of materials using ensemble averaging technique, i.e., EA method. The papers' results included measurement mechanisms, measurement uncertainty, and so on. Herein, to examine adaptability, especially in in-situ conditions, the EA method is applied to measure absorption characteristics of materials installed in two gymnasiums. A glass-wool panel with the dimension of 0.5 m by 0.5 m by 0.05 m and with the density of 32 kg m^-3 was brought around and measured to check the measurement consistency. Several measurements were conducted during badminton plays were undergoing. Measured sound absorption coefficients revealed that most results agree well with those measured in reverberation rooms. Certain improvement is necessary for the specimen brought to the in-situ measurement to keep the consistency. The inconsistency is considered to originate from unstable conditions between the specimen and floor.

Calculation of statistical absorption coefficient using ensemble averaged surface normal impedance of material

To predict and control the indoor sound field, it is important to comprehend sound absorption characteristics of building materials. In the previous studies, the authors have proposed an in-situ sound absorption measurement method of materials using ensemble averaging technique, namely EA method. The method yields a simple and efficient in-situ measurement of surface normal impedance of materials at random-incidence. In this paper, the authors calculate the statistical absorption coefficient using the surface normal impedance of material by the EA method to obtain random incidence absorption coefficient. At first, the procedure of calculating the statistical absorption coefficient from the normal impedance by EA method is described. Next, the sound absorption characteristics for five kinds of materials are measured by the EA method and the reverberation room method. Finally, the statistical absorption coefficients are calculated from results obtained by the EA method and are compared with absorption coefficients by the reverberation room method.

Measurement of solids concentration in aqueous slurries for monitoring the solids recovery in solid bowl centrifugation

Solid bowl centrifugation (SBC) is widely used for various solid-liquid separation tasks in mineral and coal processing. The SBC often suffers from a relatively high solids loss during the separation process, mainly owing to lack of an effective tool that can monitor the solids recovery. Despite its importance, the information on monitoring the solids recovery in the solid bowl centrifugation is scarce. In the present study, a strong correlation between an index (defined as the ratio of the solids concentration of the effluent by weight to the solids concentration of the feed by weight) and the solids recovery in solid bowl centrifugation was identified based on analysis of the data available in the literature. In an attempt to use this correlation for monitoring the solids recovery, a novel solids concentration measuring tool was developed to measure the solids concentration of a slurry. The tool consists of a slurry image acquisition apparatus and the backend interpolation algorithm to retrieve the concentration information from the recorded slurry images. A hybrid of the convolutional neural network and the long short-term memory network, coined as SConcNet, was built and trained with a newly created database. The SConcNet achieved a high level of accuracy and reliability in measuring the solids concentration by weight. The potential of using the index and the developed solids concentration measurement method to monitor the solids recovery of the SBC in real-time was also discussed.

NOx Detection By Pulse Polarization: Influence of Gold Electrodes

NOx Detection By Pulse Polarization: Influence of Gold Electrodes

Improved multidetector asymmetrical-flow field-flow fractionation method for particle sizing and concentration measurements of lipid-based nanocarriers for RNA delivery

Lipid-based nanoparticles for RNA delivery (LNP-RNA) are revolutionizing the nanomedicine field, with one approved gene therapy formulation and two approved vaccines against COVID-19, as well as multiple ongoing clinical trials. As for other innovative nanopharmaceuticals (NPhs), the advancement of robust methods to assess their quality and safety profiles—in line with regulatory needs—is critical for facilitating their development and clinical translation. Asymmetric-flow field-flow fractionation coupled to multiple online optical detectors (MD-AF4) is considered a very versatile and robust approach for the physical characterisation of nanocarriers, and has been used successfully for measuring particle size, polydispersity and physical stability of lipid-based systems, including liposomes and solid lipid nanoparticles. However, the unique core structure of LNP-RNA, composed of ionizable lipids electrostatically complexed with RNA, and the relatively labile lipid-monolayer coating, is more prone to destabilization during focusing in MD-AF4 than previously characterised nanoparticles, resulting in particle aggregation and sample loss. Hence characterisation of LNP-RNA by MD-AF4 needs significant adaptation of the methods developed for liposomes. To improve the performance of MD-AF4 applied to LNP-RNA in a systematic and comprehensive manner, we have explored the use of the frit-inlet channel where, differently from the standard AF4 channel, the particles are relaxed hydrodynamically as they are injected. The absence of a focusing step minimizes contact between the particle and the membrane, reducing artefacts (e.g. sample loss, particle aggregation). Separation in a frit-inlet channel enables satisfactory reproducibility and acceptable sample recovery in the commercially available MD-AF4 instruments. In addition to slice-by-slice measurements of particle size, MD-AF4 also allows to determine particle concentration and the particle size distribution, demonstrating enhanced versatility beyond standard sizing measurements.

Framework and Method for Measurement of Particulate Matter Concentration using Low Cost Sensors

Framework and Method for Measurement of Particulate Matter Concentration using Low Cost Sensors

Nitrogen Oxide Soil Emission Measurements Using Passive Samplers and Static Chamber Method

Nitrogen oxides play a major role in atmospheric chemistry, like primary pollutants, in the formation of secondary air pollutants or greenhouse gases (GHGs). This research study was conducted in the Western Pannonian sub-region of Croatia with the aim to determine the suitability of our internally developed passive sampler and static chamber method for N-NO2 concentration measurement. The aim was also to determine the impact of mineral soil fertilization on the N-NO2 flux during triticale vegetation. The research showed that the method used was suitable. Average daily N-NO2 flux ranged from 2.78 to 5.09 mg ha–1 day–1 depending on phenophase and treatment. Statistically significant differences in N-NO2 flux between two monitored treatments (300 kg N ha–1 and 0 kg N ha–1) were not observed, nor between two investigated phenophases.

Ownership control intensity, corporate financial performance and revenue growth since the global financial crisis

The 2008 global financial crisis showed that despite the corporate governance scholars and regulatory efforts of the past 30 years, shareholders’ investments remain at risk due to poor or dishonest decisions made by some distinct groups of corporate stockholders. Using structural equation modeling (SEM), this study investigated the influence of ownership control on 222 public US companies’ performance after the 2008 financial crisis. The authors identify a new construct representing a third dimension (control intensity) of ownership structure, whereas previous literature has identified only two dimensions: identity and concentration. The control intensity construct of managerial ownership was measured using the number of manager-owners among individual shareholders instead of using the traditional ownership concentration measurement method. The study indicates that the higher the individual ownership stake and the lower managerial ownership control intensity are in an organization, the stronger the negative influence of individual ownership on corporate performance and growth

Technology for gadolinium-based ultra-low-background compounds. Part 1. Studies of the impurity composition of gadolinium-containing compounds for determination of promising raw materials

The purpose of this work was to identify promising raw materials for creating composite materials that effectively capture neutrons in experiments on the study of rare physical processes. Such composites are made on the basis of a polymer matrix impregnated with gadolinium. In this case, the intrinsic radioactive background of the composite, determined primarily by the residual content of uranium and thorium, should be no more than 100 μBq/kg, which, in terms of the concentration in the materials, is no more than 1·10–9 % (wt.) for U and 2,5·10–9 % (wt.) for Th. In the study of ten commercial inorganic gadolinium-containing compounds (oxide, chloride, sulfate, nitrate) using inductively coupled plasma mass spectrometry (ICP-MS), a method was developed for determination of 65 impurity elements with a detection limit of 10–5–10–9 % (wt.) depending on the specific impurity. It is shown that when analyzing gadolinium-containing compounds by the ICP-MS method for the quantitative measurement of concentrations of difficult-to-detect elements, it is recommended to use the following isotopes: 82Se, 147Sm, 151Eu, 163Dy, 178Hf, 188Os, 194Pt. The detection limit for impurities making the greatest contribution to the residual radioactivity was reduced to 1.1·10–9 % (wt.) for U and to 1.6·10–9 % (wt.) for Th. It was found that the content of U and Th depends more on the genesis of the raw materials from which the gadolinium-containing compounds were obtained than on the general chemical purity of the compounds, which varied from 99.45 to 99.9994% (wt.) in the samples under study. The lower content of U and Th is observed in gadolinium-containing compounds obtained from the secondary raw materials (extraction phosphoric acid) or from mineral raw materials formed in sedimentary rocks (phosphogypsum). It is these compounds that should be considered as the most promising raw materials for development of the technology of the gadolinium-based ultralow-background compound, which is used as a neutron-absorbing additive in detectors and structural composite materials.This work was supported by the Ministry of Science and Higher Education of the Russian Federation, unique project identifier RFMEFI60419X0238.

A method for the simultaneous measurement of radon and thoron PAEC concentrations in air using a TLD monitor

The idea of using a device with thermo-luminescent detectors (TLD) for the simultaneous measurement of radon (Rn-222) and thoron (Rn-220) decay products’ concentrations was invented and developed in the Silesian Centre for Environmental Radioactivity at the Central Mining Institute, Katowice, Poland. The results of a preliminary analysis of the technical applicability, the required minimum period of air sampling and the optimised time schedule proved that such measurements can provide information about the potential alpha energy concentrations (PAECs) of radon and thoron decay products (TnDP).Following the analysis, preliminary measurements were performed at several locations—in a thoron chamber, in dwellings and even outdoors. Surprisingly, the maximum PAEC of the TnDP in the basement of a twin house in the Upper Silesia region was as high as 0.68 ± 0.15 µJ m−3. This paper presents the results of those measurements.

Effect of ABCB1 3435C>T Genetic Polymorphism on Pharmacokinetic Variables of Tacrolimus in Adult Renal Transplant Recipients: A Systematic Review and Meta-analysis

PurposeTacrolimus is the substrate of multidrug-resistance 1 (ABCB1). However, the effect of ABCB1 C3435T polymorphism on pharmacokinetic variables of tacrolimus is controversial in different studies. This meta-analysis was conducted to explore the relationship between ABCB1 3435C>T genetic polymorphism and pharmacokinetic variables of tacrolimus. MethodsA database search was conducted of PubMed, EMBASE, Cochrane Library, and ClinicalTrials.gov, as well as Chinese databases (SinoMed, Wan Fang, and China National Knowledge Infrastructure). We also scanned reference lists and corresponded with authors. The study explored the relationship between ABCB1 3435C>T genetic polymorphism and pharmacokinetic variables of tacrolimus stratified according to time of posttransplantation, ethnicity, methods of concentration measurement, and the initial doses of tacrolimus. FindingsSixteen studies were included in this meta-analysis. In the subgroup analysis, ABCB1 3435TT had a significantly lower weight-adjusted dose than ABCB1 3435CC, which was not observed in the ABCB1 3435CT group. The subgroup analysis then revealed that the tacrolimus concentration/weight-adjusted daily dose ratio of ABCB1 3435T carriers was significantly higher than that of the ABCB1 3435CC group at 1 and 6 months. Meanwhile, ABCB1 3435CT and TT both had a higher tacrolimus concentration/weight-adjusted daily dose ratio compared with ABCB1 3435CC. ImplicationsOur meta-analysis identified that the ABCB1 3435C>T genetic polymorphism affected the pharmacokinetic variables of tacrolimus in adult renal transplant recipients. However, individualized treatments based on genetic polymorphisms require further investigation.

Primary Productivity of Jatigede Reservoirs in Sumedang, West Java

Jatigede Reservoir is a reservoir located in Sumedang West Java which is built for irrigation, raw water, power generation, tourism, and capture fisheries. This research aims to determine the value of primary productivity as one of the indicators of the water body feasibility of the Jatigede reservoir to capture fisheries activities. The study was conducted in August – September 2019. Sampling is carried out at 4 stations on the surface, half the depth of compensation, and the depth of compensation. Estimation of primary productivity using chlorophyll-a concentration measurement method. The results of measurement of water quality parameters in the Jatigede reservoir include transparency range of 19,5 cm – 116,5 cm, temperature with a spread of 26,58 – 27,48oC, pH with a range of 7,69 – 8,40, carbon dioxide with a range of 4,190 mg/L – 9,219 mg/L, current ranges from 0.136 m/s – 0,216 m/s, BOD5 with a range of 11,027 dissolved oxygen ranges from 6,4 mg/L – 7,1 mg/L, ammonia ranges from 0,006 mg/L – 0,039 mg/L, nitrates ranged from 0,168 mg/L – 0,216 mg/L, and phosphate range 0,139 mg/L – 0,185 mg/L. Results from the measurement of chlorophyll-a ranged from 0,035 mg/L – 0,062 mg/L. This results in showing the Jatigede reservoir of oligotrophic water because the primary productivity in the waters of the Jatigede Reservoir is relatively low if calculated based on the concentration of chlorophyll-a.

Concentration measurement without calibration of natural sediment particles using backscatter sensing with optical fibres

A set of newly developed miniature optical fibre sediment concentration measuring instrument is used for the concentration measurement of natural sediments. Through calibration with natural sediments of different particle size distributions collected from different beaches in China, we establish two unified relations between natural sediment concentration and output voltage of optical backscatter intensity to obtain the natural sediment concentration without calibration. The concept of the compositional weighted sediment size is proposed to characterize the optical backscatter property of natural sediments, which is more accurate for non-calibration sediment concentration measurement. On the premise that particle size distribution of natural sediments is known, it is no longer necessary to calibrate sediment concentration, and the unified relations can be used to directly measure sediment concentration, which provides a new highly convenient concentration measurement method of natural sediments.

Comparative study on protein quantitation by digital PCR with G2-EPSPS as an example

Protein quantification is an important issue for pharmaceutical development, clinical diagnosis, and food safety. Generally, protein concentration is relatively quantified with an external standard by high performance liquid chromatography, mass spectrometry, immunoassay and so on. However, as a molecular biological method, PCR is commonly used for nucleic acid analysis. With the proximate ligand assay approach, quantitative PCR (qPCR) could be also used for protein quantitation. Digital PCR (dPCR) is recently proposed for absolutely quantitation of nucleic acid with the advantage of high accuracy and less interference without external standard. With the aid of proximate ligand assay approach, dPCR could be also potentially used for both relative and absolute protein quantitation. However, less work has been reported for the method performance of PCR based protein quantitation. In this paper, we have developed both relative and absolute quantitation methods by qPCR and dPCR with G2-EPSPS protein as an example. Traditional ELISA method was also developed as comparison. Isotope dilution mass spectrometry (IDMS), which is primary method for protein quantitation based on its primary sequence, was used to assign the accurate concentration of G2-EPSPS for comparison. The method performance was thoroughly evaluated. For relative quantitation, it revealed that the dPCR showing better repeatability and reproducibility compared with qPCR and ELISA methods, especially for higher level sample analysis. And qPCR showed similar repeatability and reproducibility as ELISA method. It is interesting that the absolute concentration obtained by dPCR was much lower than that obtained by IDMS. One possible reason was that only those binding to both mAbs simultaneously could be quantified by dPCR, therefore, it is kind of “active concentration”. Comparatively, the concentration obtained by IDMS was just based on the primary sequence of protein. The study demonstrated the potential advantage of dPCR used for relative protein quantitation and the risk of lower concentration obtained by dPCR when it was used for absolute protein quantitation. However, the dPCR could be a potential primary method for active protein concentration measurement. This study could benefit the correct development and usage of protein quantitation methods based on dPCR. It is also anticipated that the dPCR based protein quantitation could be widely used in the future.

Nanoparticle number concentration measurements by multi-angle dynamic light scattering

We present the use of Multi-angle Dynamic Light Scattering (MADLS®) for the measurement of nanoparticle concentration. We describe the theory of the method and its application to nanoparticles made of gold, silica and polystyrene, with diameters ranging from 30 to 400 nm, and demonstrate some of the limitations with particles of sizes 500 nm and above. We evaluate the method accuracy, linearity and reproducibility, as well as the operational nanoparticle concentration and size range. We show that the concentration working range depends on the material’s optical properties, size and concentration. Here it is shown that the level of accuracy that can be expected for the concentration of particles is typically within 50% of the nominal value across a range of materials and sizes and, for some samples, within 20%. The repeatability of the measurements, in terms of relative standard deviation, is typically below 30%. A linearity of within 40% across a concentration range of 3·108 to 2·1011 mL−1 for concentration measurements was also demonstrated by using gold nanoparticles and gravimetric dilutions for method validation. Overall, we show that MADLS® is a rapid and straightforward method for the reproducible measurement of particle concentration, as well as size, requiring minimal sample preparation, without the need to calibrate using a pre-determined concentration series, and applicable to a broad range of materials. These features make it an ideal tool to support both development and quality control of particle materials for a broad range of applications.

NOx Detection By Pulse Polarization: Influence of Gold Electrodes

NOx Detection By Pulse Polarization: Influence of Gold Electrodes

Determination of Rifampin Concentrations by Urine Colorimetry and Mobile Phone Readout for Personalized Dosing in Tuberculosis Treatment.

Individual pharmacokinetic variability is a driver of poor tuberculosis (TB) treatment outcomes. We developed a method for measurement of rifampin concentrations by urine colorimetry and a mobile phone photographic application to predict clinically important serum rifampin pharmacokinetic measurements in children treated for TB. Among spiked urine samples, colorimetric assay performance was tested with conventional spectrophotometric and the mobile phone/light box methods under various environmental and biologic conditions. Urine rifampin absorbance (Abs) was then determined from timed specimens from children treated for TB in Tanzania, and compared to serum pharmacokinetic measurements collected throughout the dosing interval. Both the mobile phone/light box and spectrophotometry demonstrated excellent correlation across a wide range of urine rifampin concentrations (7.8-1000 mg/L) in intra- and interday trials, 24-hour exposure to ambient light or darkness, and varying urinalysis profiles (all r ≥ 0.98). In 12 Tanzanian children, the urine mobile phone/light box measurement and serum peak concentration (Cmax) were significantly correlated (P = .004). Using a Cmax target of 8 mg/L, the area under the receiver operating characteristic curve was 80.1% (range, 47.2%-100%). A urine mobile phone/light box threshold of 50 Abs correctly classified all patients (n = 6) with serum measurements below target. The urine colorimetry with mobile phone/light box assay accurately measured rifampin absorbance in varying environmental and biological conditions that may be observed clinically. Among children treated for TB, the assay was sensitive for detection of low rifampin serum concentrations. Future work will identify the optimal timing for urine collection, and operationalize use in TB-endemic settings.

A momentum-based method for the mass concentration measurement of pneumatically conveyed solid: design optimization

Mass concentration measurement of pneumatically conveyed solid is still challeging in industry. In our previous work (Liu G.Q., The 5th International Conference on Advances in Energy Resources and Environment Engineering, December 6-8, 2019, Chongqing, China.), a novel momentum-based method with more reliable measurement mechanism and simpler structure was developed and computationally validated with a one-end closed straight tube. In this paper, optimization on the structure of the metering tube is conducted to improve the measurement sensitivity represented by the conversion factor k. Tubes with a conical inlet are found to possess higher k than that of the straight tube. Computational fluid dynamics (CFD) computations show that k generally increases with decreasing half-cone angle at fixed radius and decreases with decreasing restitution coefficient of collision between particles and the tube walls.

Quantitative Measurement of a Chiral Drug in a Complex Matrix: A J-Compensated Quantitative HSQC NMR Method.

We developed a J-compensated QHSQC NMR method for the quantitative measurement of enantiopurity and concentration of levofloxacin in a complex drug matrix. The pulse sequence can achieve uniform signal responses by the suppression of the heteronuclear coupling modulation and alleviation of the homonuclear coupling evolution. Furthermore, we discuss the influence of relaxation on peak intensities and propose the selection conditions of reference signals to achieve accurate quantifications. The evaluation of the methodology shows that the results obtained by selected peaks are in accordance with theoretical analysis with good reliability and linearity. The enantiomeric separation and quantification of levofloxacin in creams are achieved by using a chiral solvating agent, a reference compound, and the J-compensated QHSQC pulse sequence. To our knowledge, this is the first example of QHSQC methodology to quantify enantiomers in the complex matrix.

A Momentum-Based Method for the Mass Concentration Measurement of Pneumatically Conveyed Solid: Computational Verification

A momentum-based method is proposed to measure the mass concentration of solids in pneumatic pipelines. The mechanism relies on the fact that particles flowing with the fluid will exert drag force and thus induce pressure increase on the fluid phase when they decelerate as approaching a static object or space in the flow domain. The pressure increase is expected to increase with the mass concentration of particles and the fluid velocity, and is also affected by the particles size and density. A conversion factor that indicates the extent to which particle momentum is converted to the fluid static pressure increase was defined. Computational verification of the mechanism was carried out with pulverized coal flow around a one-end closed tube with its opening facing towards the incoming flow. The pressure increase was quantitatively comparable to the fluid dynamic pressure when the solid-to-fluid mass ratio was of the same order of magnitude. The conversion factor was found insensitive to particle size over a wide range, which is advantageous since particle size distribution are usually not known in advance. Compared to most existing techniques, current mechanism is more robust and economic in industry field measurements.