Simple Estimation Method Research Articles

Development and validation of RP-HPLC method for estimation of anti- hypothyroidism drug in capsule dosage form

A simple, accurate, sensitive and precise Reverse Phase-High Performance Liquid Chromatographic assay method for estimation of Levothyroxine sodium in dosage form was successfully developed. The chromatographic separation was performed on Welch Ultisil XB-CN, 150 x 4.6 mm, 5µm. column. The mobile phase consists of 0.05% OPA Buffer solution, and Acetonitrile in the ratio of 72:28, v/v. Mobile phase was delivered at a flow rate of 1.0 ml/min. Samples were injected 50 μL the column temperature was kept at 40 0C and sample temperature 150C. The wavelength 221 nm were selected for the evaluation of the chromatogram. The retention time of the drug was found to be 3.7 min. The developed method was found to be linear in a concentration range of 5-15 μg/ml of the drug (r2= 0.999). The low value of % RSD indicates reproducibility of the method. Thus this method can be used for routine analysis of pomalidomide in formulation and to check the stability of bulk samples.

THE PRELIMINARY STUDY ON IMPLEMENTING A SIMPLIFIED SOURCE TERMS ESTIMATION PROGRAM FOR EARLY RADIOLOGICAL CONSEQUENCES ANALYSIS

Indonesia possesses numerous potential sites for nuclear power plant development. A fast and comprehensive radiological consequences analysis is required to conduct a preliminary analysis of radionuclide release into the atmosphere, including source terms estimation. One simplified method for such estimation is the use of the Relative Volatility approach by Kess and Booth, published in IAEA TECDOC 1127. The objective of this study was to evaluate the use of a simple and comprehensive tool for estimating the source terms of planned nuclear power plants to facilitate the analysis of radiological consequences during site evaluation. Input parameters for the estimation include fuel burn-up, blow-down time, specific heat transfer of fuel to cladding, and coolant debit, using 100 MWe PWR as a case study. The results indicate a slight difference in the calculated release fraction compared to previous calculations, indicating a need to modify Keywords: Source terms, Relative volatility, Release fraction, PWR, SMART

Simplified estimation of wave attenuation in marginal ice zone using homogenized scattering model

A theoretical model to explain the scattering process of wave attenuation in a marginal ice zone is proposed. Although many numerical methods have been developed to accurately estimate wave attenuation, it is not easy to incorporate this knowledge and results into practical use. Therefore, a simplified estimation method is developed here to explicitly and simply describe its fundamental mechanisms. We consider a periodic array of ice floes, where the floe is modeled by a vertical rigid cylinder. Using a homogenization technique, a homogenized free surface equivalent to the array is obtained. Then, we show that a dispersion relation of the homogenized free surface waves makes all wave numbers complex. As a result, the exponential energy decay in the scattering process is demonstrated. Under the deep water assumption, the wave attenuation coefficient is proportional to the open water’s wave number, ice concentration ratio, and imaginary part of the floe’s heave motion. To validate the proposed theory, a tank experiment was also conducted using cylindrical synthetic ice plates. Although our model is obtained under many simplifications, the theoretical results show the same tendency and order as the experimental results.

Development and validation of simultaneous quantification method for gemcitabine and betulinic acid: augmenting industrial application.

Combinatorial treatment utilizing a nucleoside analogue gemcitabine (GEM), with a characteristic pentacyclic triterpenoid betulinic acid (BET), has exhibited empowering adequacy in the therapy of cancer. It lessens the advancement of collagen and upgrades the saturation of tumour medicines. With the advancement in nanotechnology, the co-loaded formulation urges for a validated method of estimation. The purposed work entails a robust, simple, and economical analytical method for the simultaneous estimation of GEM and BET through RP-HPLC. Orthophosphoric acid (0.1%)-acetonitrile was considered as the mobile phase for the detection of GEM and BET at 248nm and 210nm with retention times of 5min and 13min, respectively. The method was further validated as per the regulatory guidelines with all the parameters found within the limit. The developed method with adequate resolution and quantification was found to be linear, accurate, precise, robust, and stable with an intra- and inter-day variability of less than 2%. The method was found specific for GEM and BET with no matrix interference of drug-spiked FBS samples. To demonstrate the applicability of the developed method, a nano-formulation containing GEM and BET was prepared and assessed for various parameters including encapsulation efficiency, loading efficiency, drug release, and drug stability. The method developed can be a possible tool for the simultaneous quantification of GEM-BET in analytical and biological samples.

Simple Estimation Method for Water Quality in Swine Wastewater Treatment Facilities

Simple Estimation Method for Water Quality in Swine Wastewater Treatment Facilities

Persistence modeling for sales prediction: A simple, self-contained approach

The accurate prediction of future retail sales is crucial in business. Marketing persistence modeling is a well-established framework for the analysis of retail sales dynamics using a time series approach. However, dominant academic approaches to persistence modeling are rather complex, requiring sophisticated analytic and computing skills. We introduce a decision making approach that allows jointly testing and predicting the evolution of retail sales using a state-space model. We first propose a model, which incorporates the foundations of persistence modeling, and provide a simple estimation method. Secondly, we show a formal procedure for detecting persistence and, hence, selecting parameters to predict future data. An empirical investigation carried out over nearly 30000 Walmart retail sales, shows that our model provides significantly better prediction performance when compared to standard benchmarks. The combination of simplicity and efficiency makes our approach appealing not only for scholars but also for practitioners.

Evaluation of surface reflectance retrieval over diverse surface types using SREM algorithm in varied aerosol conditions for coarse to medium resolution data from multiple spaceborne sensors

ABSTRACT Surface reflectance (SR) is one of the most important components for deriving different biophysical parameters from remotely sensed data. For accurate retrieval of SR, it is essential to accurately estimate the degree of atmospheric alteration to the target signals reaching at-sensor. Simplified and robust SR estimation method (SREM) is one such approximate estimation method that could demonstrate the retrieval of SR from top-of-atmosphere (ToA) signals, without using any precalculated LUTs or aerosol information. The present study attempts to assess the accuracy of the SREM algorithm over varied Indian land surfaces using data from Landsat 8, Sentinel 2, AWiFS and LISS III. The results indicate that while SREM performs quite well for Sentinel 2 over most land surface types, the performance is good for Landsat 8 as well except over water and in coastal aerosol band. SREM retrievals also show high correlation for AWiFS and LISS III but the estimated values are much lower than level 2 SR due to smaller ToA reflectance values. Furthermore, while aerosol load does impact the performance adversely, it is least impactful for Sentinel 2 and LISS III datasets and most over Landsat 8, particularly over water. Additionally, while AWiFS and LISS III SR retrievals are underestimated at all spectral bands, retrieval is slightly underestimated from green to SWIR band in case of Sentinel 2 and SWIR band in case of Landsat 8. Overall, the findings demonstrate that while SREM will need to be modified to adapt to LISS III and AWiFS retrievals, it can, nevertheless, be readily used as a simplified method for quick and approximate estimation of SR over the Indian region using data from Landsat 8 and Sentinel 2.

FPGA Implementation of Integer Loop Delay Estimation with Low Complexity in Undersampling Digital Predistortion System

In a digital predistortion (DPD) system, accurate loop delay estimation is one of the prerequisites for precise calculation of the DPD coefficient. Multiplications of plural numbers are needed in most of the conventional loop delay estimation algorithms. Based on the Euclidean loop delay estimation (ELDE) method, this paper proposes a simplified Euclidean loop delay estimation (SELDE) method that can avoid the operation of the multiplication of plural numbers. The ELDE and SELDE method are implemented in actual undersampling systems, separately. The results of the experiments prove the feasibility and effectiveness of the methods. Compared with the ELDE method, the hardware resource consumption of SELDE is decreased, mainly reflected in the reduction of registers and look-up tables by 41.26% and 42.84%, respectively.

Thrust force requirements in fault zones with squeezing ground

Shield jamming constitutes a critical hazard in mechanized tunnelling under squeezing conditions. These are often encountered within narrow fault zones interspersed between competent rock layers, where the competent rock exhibits much smaller deformations, thus mobilising shear stresses at the interfaces. This so-called “wall-effect” results in substantially reduced deformations and rock pressures in the fault zone and is thus favourable with respect to shield jamming. Building on existing design nomograms for evaluating the required thrust force in homogeneous ground, this paper proposes two novel, simple and practical thrust force estimation methods that additionally consider the favourable influence of the wall-effect in narrow fault zones. The first method performs an a priori modification of the nomogram input via an equivalent improved ground stiffness that depends on the fault zone length. The second method performs an a posteriori correction of the nomogram output via an analytically determined coefficient, established via multiparametric regression that considers the results of 3450 numerical analyses. Both methods allow for a fast evaluation of the required thrust force in fault zones with reasonable accuracy, thereby providing a valuable tool for design.

A Novel Validated RP-HPLC Method For the Estimation of Salmeterol By DOE

Background: Salmeterol is a long-acting beta agonist (LABAs) Salmeterol is hypothesized to bind to 2 sites on the beta-2 adrenoceptor. The saligenin moiety binds to the active site of the beta-2 adrenoceptor. The hydrophilic tail of salmeterol binds to leucine residues in the exo-site of the beta-2 adrenoceptor almost irreversibly, allowing salmeterol to persist in the active site, which is responsible for its long duration of action. Method: A new, simple, accurate, rapid, precise, reproducible and cost-effective RP-HPLC method for the quantitative estimation of Salmeterol in bulk and pharmaceutical dosage form. The developed RP-HPLC method for the quantitative estimation of Salmeterol is based on measurement of absorption at maximum wavelength 254 nm using Phosphate buffer: Methanol PH 2.5 (35:65 v/v) as a solvent. The stock solution of Salmeterol was prepared, and subsequent suitable dilution was prepared in mobile phase to obtained standard curve. The standard solution shows absorption maxima at 254 nm. Results: The Salmeterol obeyed Beer Lambert’s law in the concentration range of 20-100μg/ml with regression 0.999 at 254 nm. The overall % recovery was found to be 99.78% for Salmeterol which reflects that the method was free from the interference of the impurities and other excipients, used in the bulk and marketed dosage form. The low value of % RSD was indicative of accuracy and reproducibility of the method. The % RSD for inter-day and intra-day precision was found to be 0.2 for Salmeterol respectively which is <2% hence proved that method is precise. Conclusion: In the present study, novel reverse phase High performance liquid chromatography method for simultaneous determination of Salmeterol in pharmaceutical dosage form was developed. The developed method was validated for various parameters such as accuracy, precision, ruggedness, linearity, robustness, system suitability, specificity as per ICH guidelines.

Doe Approach: A Validated Rp -Hplc Method For The Determination Of Dapagliflozin

Background: Dapagliflozin is a competitive inhibitor of sodium / glucose co transporter 2 (SGLT2). It will Inhibiting the reabsorption of filtered glucose in the kidney leads to elevated urinary glucose excretion, thereby lowering blood Method: A new, simple, accurate, rapid, precise, reproducible and cost-effective RP-HPLC method for the quantitative estimation of Dapagliflozin in bulk and pharmaceutical dosage form. The developed RP-HPLC method for the quantitative estimation of Dapagliflozin is based on measurement of absorption at maximum wavelength 254 nm using 0.1% urea: methanol (35:65% v/v) as a solvent. The stock solution for Dapagliflozin was prepared, and subsequent suitable dilution was prepared in mobile phase to obtained standard curve. The standard solution of Dapagliflozin shows absorption maxima at 254 nm. Results: Dapagliflozin will obeys Beers -Lamberts law in the concentration range of 20 - 100μg/ml with regression 0.999 at 254nm.The overall % recovery was found to be 101.59% for Dapagliflozin which reflects that the method was free from the interference of impurities and other impurities, used in bulk and marketed dosage forms. The low value of % RSD was indicative of accuracy and reproducibility of the method. The % RSD for inter-day and intra-day precision was found to be 0.1 for Dapagliflozin respectively which is & it <2% hence proved that method is precise. Conclusion: The results of analysis have been validated as per International Conference on Harmonization (ICH) guidelines. The developed method can be adopted in routine analysis of Dapagliflozin in bulk and tablet dosage form. The Proposed method was found to be rapid, accurate, precise, specific, robust, rugged and economical.

Observation of nitrogen oxide-influenced chlorine chemistry and source analysis of Cl2 in the Yangtze River Delta, China

Atmospheric chlorine (Cl)- and nitrogen (N)-containing species such as Cl2, ClNO2, and N2O5 participate actively in atmospheric chemistry by triggering radical reactions that lead to the formation of secondary pollutants. Despite of their importance in atmospheric chemistry, the measurements of these species are scarce, due to analytical challenges. Herein, we report observation results of Cl2, ClNO2, and N2O5 from measurements using high-resolution time-of-flight chemical ionization mass spectrometry (HR-ToF-CIMS) in Shanghai and Changzhou in the highly industrialized and populated Yangtze River Delta (YRD) of East China. In Changzhou, the maximum concentrations of N2O5, ClNO2, and Cl2, were 0.4, 1.3, and 0.5 ppbv (1-min averages), respectively, while they were 0.5, 5.7, and 1.1 ppbv, respectively, in Shanghai. Much higher ClNO2 levels were found in Shanghai compared to Changzhou, although the concentrations of the precursor (N2O5) are similar, indicating different heterogenous N2O5 uptake and Cl activation efficiency at these two sites. The diurnal variation of Cl2 in Shanghai shows a strong daytime peak, which is contradictory to its fast lost by photolysis during daytime; the diurnal pattern of Cl2 in Changzhou shows a prominent night peak and a much smaller daytime peak than that in Shanghai. The heterogeneous uptake of ClNO2 and the photolysis of O3 on chloride-containing aerosols are believed to contribute to efficient Cl2 formation at night and day, respectively. The estimated heterogeneous uptake coefficient of O3 is 0.004 ± 0.007, with a maximum of 0.034. Further analysis on these heterogeneous reactions with the help of aerosol composition data (chloride, liquid water content, pH etc.) was also performed to ascertain the role of the secondary formation of Cl2 in daytime Shanghai. Through simple estimation methods, the maximum daytime production rate of Cl2 was estimated to be 0.95 ppbv h−1, while daytime photolysis of Cl2 contributed to 98% of Cl formation. Our results indicate that there is a large secondary source of Cl2 in the YRD region during the day, which can contribute substantially to Cl formation and requires more investigations.

QbD based RP-HPLC method for simultaneous determination of a emtricitabine, tenofovir diproxil fumarate and efavirenz in tablet dosage form-an application to stability indicating assay

The current studies entail Quality by Design (QbD)-enabled development of a simple, rapid, sensitive and cost-effective high-performance liquid chromatographic method for estimation of emtricitabine (EMT), tenofovir diproxil fumarate (TEN), and efavirenz (EFA) in combined dosage form. Systematic optimization was performed employing Box-Behnken design by selecting the flow rate, buffer molarity, and acetonitrile volume as the critical method parameters (CMPs) identified from screening studies, thus evaluating the critical analytical attributes (CAAs), namely, retention duration, theoretical plates, resolution, and asymmetry factor as the parameters of method robustness. The optimal chromatographic separation was achieved using acetonitrile and phosphate buffer (pH 3.0) 74.1:25.9 v/v as the mobile phase with a flow rate 0.91 mL/min, and UV detection at 260 nm. The method was validated as per the ICH recommended conditions, which revealed high degree of linearity, accuracy, precision, sensitivity and robustness over the existing liquid chromatographic methods of the drug. Studies on forced degradation under acid, basic, oxidative, photolytic, and thermal conditions revealed the drug’s well-resolved peak and the degradation products’ peaks as well.

An Approach for Shipping Emissions Estimation in Ports: The Case of Ro–Ro Vessels in Port of Vigo

Despite most atmospheric emissions being produced by vessels when navigating at sea, they are also important when in port because of their proximity to urban areas and their harmful effects on climate change and health. First, we carried out a bibliographical review of the nine most relevant methods to estimate the emission of ships in ports. These methods have been used to estimate the emissions of the sixteen most representatives Ro–Ro (roll-on–roll-off) ships calling at the Port of Vigo. From the results obtained, a new simplified method for estimation is proposed, which is based on linear regression curves and takes into account the number of ships and the average number of hours they remain in port annually. This simplification could be a useful tool when making preliminary assessments of the emissions from ships in port, which can also be extrapolated to other ports or types of ships.

A Simple Method for Estimation of the Scattering Exponent of Nanostructured Glasses

For most of nanostructured glasses (NGs) (phase-separated glasses and glass-ceramics), the light scattering coefficient (turbidity) is described by a power function of the inverse wavelength with an exponent which differs appreciably from the Rayleigh value 4 and is called the scattering exponent. The knowledge of the scattering exponent of a material is important from both fundamental and practical points of view. Previously, we developed three rather complex methods to determine the scattering exponent. Here, we present a novel simple express method for its estimation. In the method, the measured optical density for only one sample is used, the refractive index of the material is not required, and the dispersion of refractive index is assumed to be insignificant. The method is based on the differentiation of the measured optical density with respect to the wavelength. The scattering exponent values obtained by the new method for NGs of different types are in good agreement with those found by the traditional methods. The new method is found to be applicable even to NGs with high dispersion of refractive index. Thus, the new method does not require the data on the refractive index dispersion and can be applied without restrictions.

A novel state-of-energy simplified estimation method for lithium-ion battery pack based on prediction and representative cells

Accurate online state of energy (SOE) estimation of a series-connected lithium-ion battery pack is very important for the driving range estimation of electric vehicles, which is still an urgent problem to be solved due to the high computational complexity caused by cell-to-cell inconsistency under practical application of the existing battery management system. In the manuscript, a novel low-complexity SOE simplified estimation method for lithium-ion battery pack based on prediction and representative cells is proposed. Firstly, two cells in the battery pack, one of which has the smallest remaining discharge capacity and the other of which reaches at or closest to the lower cut-off voltage during the discharge process, are selected as representative cells. Secondly, after the EKF algorithm is applied to achieve SOC estimation, the future states of the representative cells are accurately predicted to obtain the cut-off discharge time and the discharge capacity based on the thermoelectric coupling equivalent circuit model under the condition that the future output current of the battery pack has been predicted. The output energy of the representative cells during prediction is divided into three output energy generation parts contributed by OCV, ohmic resistance and polarization resistance respectively, and the three parts are cumulatively calculated and summed to obtain the remaining discharge energy of the representative cells. Thirdly, the approximately proportional relationships in three output energy generation parts between the representative and the non-representative cells are established based on the approximately proportional expressions of the three parts of all cells, and a simplified calculation method is subsequently applied to obtain the remaining discharge energy of non-representative cells based on the results of representative cells. Finally, the remaining discharge energy and SOE of the battery pack can be obtained. The results verified by complex dynamic condition experiments at different temperatures show that the maximum absolute error of the SOE estimation results is less than 3% and more than 85% of the calculation time is saved, which demonstrates that the developed method can achieve accurate and simple SOE estimation of the battery pack.

A Simple HPTLC Approach of Quantification of Serratol and Tirucallic Acid with Boswellic Acids in Boswellia serrata by Validated Densitometric Method with MS/MS Characterization.

This study was planned to develop a simple high-performance thin-layer chromatography method for qualitative and quantitative estimation of 3-acetyl-11-keto-β-boswellic acid (AKBBA), β-boswellic acid (BBA), 3-oxo-tirucallic acid (TCA) and serratol (SRT) with HPTLC-ESI-MS/MS for characterization in Boswellia serrata Roxb. oleo gum resin extract. The method was developed with hexane-ethyl acetate-toluene-chloroform-formic acid as mobile phase. RF values observed for AKBBA, BBA, TCA and SRT were 0.42, 0.39, 0.53 and 0.72, respectively. The method was validated according to International Council for Harmonisation guidelines. The concentration range for linearity was 100-500ng/band for AKBBA and 200-700ng/band for the other three markers with r2 > 0.99. The method resulted in good recoveries as 101.56, 100.68, 98.64 and 103.26%. The limit of detection was noticed as 25 , 37, 54 and 38ng/band, with a limit of quantification as 76, 114, 116 and 115ng/band, for AKBBA, BBA, TCA and SRT, respectively. The four markers were identified and confirmed in B. serrata extract using TLC-MS by indirect profiling by LC-ESI-MS/MS and were identified as terpenoids, TCA and cembranoids: AKBBA (mass/charge (m/z) = 513.00), BBA (m/z = 455.40), 3-oxo-tirucallic acid (m/z = 455.70) and SRT (m/z = 291.25), respectively.

A new perspective of solar hot water system operation optimization: Supply and demand matching

Solar hot water (SHW) systems have been widely used in residential buildings for energy conservation and emission reduction. The system operation control from the supply side and the occupant's hot water behavior on the demand side both affect the energy performance of the SHW system. However, there is a lack of synergistic optimization analysis of the supply-demand matching process. Therefore, in this study, quantitative methods for describing the supply- and demand-side equivalent profiles of SHW systems were proposed. Based on the two equivalent profiles, commonly used regulation measures on the supply and demand sides were analyzed from the perspective of time and intensity modification by proposing simplified estimation methods for the adjustment effect. Five supply side adjustment strategies are investigated. Through a questionnaire, three specific demand-side guidance strategies were obtained to guide the user's hot water behavior, and it was found that the performance of these strategies differed in different user groups. Integrated supply and demand matching regulation processes were established and verified. The results showed that the proposed supply-demand matching optimization process can increase the annual solar energy utilization rate by 9.6%, which meant that one household could save 136.19 kWh of reheating energy and reducing 121.51 kg CO2 in a year.

A simple method for annual sediment transport estimation at ungauged cross-sections and its application to assess sustainable sand mining from river margins in Uruguay

Estimation of sediment transport rate in rivers is a complex task that requires a large amount of information, resulting in the need for a considerable budget to address related problems. In this work, a methodology is proposed for mean annual sediment transport estimations at ungauged reaches, based on a simplified calculation of the channel-forming discharge. It consists of (1) determination of the channel-forming discharge from a simulated monthly flow series and a sediment rating curve; (2) calculation of the sediment transport rate corresponding to the channel-forming discharge through the sediment rating curve, and (3) determination of the mean annual transport under the assumption that the channel-forming discharge flows constantly for a year. The method was tested in the Santa Lucía basin, Uruguay. It was validated for the case study by applying it to a gauged cross-section and then used in other ungauged reaches of the basin to assess the sustainability of sediment mining from river margins. Results show that the proposed method tends to overestimate the annual transport. Nevertheless, it is a useful practical tool to set a limit to the annual sediment volume extracted by sand mining at river margins, and to estimate the order of magnitude of annual sediment transport in data-scarce rivers.

New Method of NPOH Equation-Based to Estimate the Physicochemical Properties of Noncyclic Alkanes.

Changes in various physicochemical properties (P (n)) of noncyclic alkanes can be roughly classified as linear and nonlinear changes. In our previous study, the NPOH equation was proposed to express nonlinear changes in the properties of organic homologues. Until now, there has been no general equation to express nonlinear changes in the properties of noncyclic alkanes involving linear and branched alkane isomers. This work, on the basis of NPOH equation, proposes a general equation to express nonlinear changes in the physicochemical properties of noncyclic alkanes, including a total of 12 properties, boiling point, critical temperature, critical pressure, acentric factor, heat capacity, liquid viscosity, and flash point, named as the "NPNA equation", as follows: ln(P (n)) = a + b(n - 1) + c(S CNE) + d (ΔAOEI) + f(ΔAIMPI), where a, b, c, and f are coefficients, and P (n) represents the property of the alkane with n carbon atom number. n, S CNE, ΔAOEI, and ΔAIMPI are number of carbon atoms, sum of carbon number effects, average odd-even index difference, and average inner molecular polarizability index difference, respectively. The obtained results show that various nonlinear changes in the properties of noncyclic alkanes can be expressed by the NPNA equation. Nonlinear and linear change properties of noncyclic alkanes can be correlated with four parameters, n, S CNE, ΔAOEI, and ΔAIMPI. The NPNA equation has the advantages of uniform expression, usage of fewer parameters, and high estimation accuracy. Furthermore, using the above four parameters, a quantitative correlation equation can be established between any two properties of noncyclic alkanes. Employing the obtained equations as model equations, the property data of noncyclic alkanes, involving 142 critical temperatures, 142 critical pressures, 115 acentric factors, 116 flash points, 174 heat capacities, 142 critical volumes, and 155 gas enthalpies of formation, a total of 986 values, were predicted, which have not be experimentally measured. NPNA equation not only can provide a simple and convenient estimation or prediction method for the properties of noncyclic alkanes but also can provide new perspectives for studying quantitative structure-property relationships of branched organic compounds.