Mass Distribution Data Research Articles

Rapid Evaluation Model of Endurance Performance and Its Application for Agricultural UAVs

Current developments in agricultural aviation technology have gradually increased the requirements for the endurance of agricultural unmanned aerial vehicles (UAVs). It is significant to establish an endurance evaluation model for different types of UAVs and rationalize the battery and operating load parameters on this basis, which play an important role in improving the operational efficiency of the whole UAV. Taking the quad-rotor UAV as the research object, firstly, the structural composition of the whole UAV is studied in this paper, and then the main influencing parameters of the UAV endurance evaluation model are determined, combined with the mass distribution data of specific models. Based on the above, the hovering output power of the UAV is modularly divided, and a fast measurement method is innovatively proposed to sample and fit the power data of each module. Finally, in combination with the variation law of the lithium battery discharge time, a rapid evaluation method of the endurance time of agricultural UAVs is derived and validated by the hovering test data of the agri-drone with a standard operating load of 5 kg. The results show that the mass distribution system of the UAV has the highest percentage of operational load mass (40.45% under the standard configuration); the power distribution system has the highest percentage of motor pull curve output power (91.12% under the standard configuration); the maximum error of the surface verification point in the validation experiment is 2.73%, and the model is of relatively high accuracy. The modeling idea and the supporting module power rapid measurement method can quickly model and evaluate the endurance of common agricultural drones, guide reasonable matching between the battery and operating load, and are of great significance in improving UAVs’ endurance and operational efficiency.

Multi angle light scattering as a process analytical technology tool for real-time monitoring of molar mass of protein-polysaccharide conjugate fractions

Current polysaccharide conjugate vaccine manufacturing process involves conjugation of polysaccharide with protein followed by separation/purification of the conjugate from reaction components and free polysaccharide/protein, by preparative Size-Exclusion Chromatography (SEC). Each SEC fraction is analyzed and pooled the conjugate based on its molar mass and absence of free polysaccharide. In the present work, we have evaluated in-line Multi Angle Light Scattering (MALS) as a Process Analytical Technology (PAT) tool to eliminate the need for offline analysis of individual fractions after purification. The preparatory SEC unit is coupled to a MALS detector, i.e. preparatory SEC-MALS. In SEC, the molecules are separated based on size, where polysaccharide-protein conjugate elutes first followed by free polysaccharide and then free protein. The MALS detector monitors in-line weight-average molar mass (Mw) during SEC-fractionation. Except the first fraction, the molar mass distribution data from in-line MALS enables decision on preparative SEC fractions to be pooled. We found that offline analysis of preparative fractions using analytical SEC-MALS was in good agreement with the >2000 kDa cutoff criterion. Thus in-line process analysis is effective, time-saving, and simple to implement in manufacturing processes of conjugate vaccines.

Modeling microalgae cell mass distributions using the Fokker–Planck equation

The modeling of the cell mass distribution for microalgae growth processes is addressed using the Fokker–Planck equation for a stochastic logistic growth model of a single cell. Relations between the proposed model and the classical Droop model used for mass– balance based modeling of the algae growth are established. The proposed model is evaluated using experimentally obtained cell mass distribution data for the microalgae Chlamydomonas reinhardtti showing a good correspondence between measurements and model predictions. The obtained model is considerably simpler in comparison to cell mass population balance models used so far to describe the temporal behavior of the cell mass distribution.

Quantifying avian inertial properties using calibrated computed tomography.

ABSTRACTEstimating centre of mass and mass moments of inertia is an important aspect of many studies in biomechanics. Characterising these parameters accurately in three dimensions is challenging with traditional methods requiring dissection or suspension of cadavers. Here, we present a method to quantify the three-dimensional centre of mass and inertia tensor of birds of prey using calibrated computed tomography (CT) scans. The technique was validated using several independent methods, providing body segment mass estimates within approximately 1% of physical dissection measurements and moment of inertia measurements with a 0.993 R2 correlation with conventional trifilar pendulum measurements. Calibrated CT offers a relatively straightforward, non-destructive approach that yields highly detailed mass distribution data that can be used for three-dimensional dynamics modelling in biomechanics. Although demonstrated here with birds, this approach should work equally well with any animal or appendage capable of being CT scanned.

Methanolysis of carboxymethyl cellulose: a comprehensive study

Two commercial carboxymethyl celluloses (CMC) with degree of substitution (DS) 0.75 and 0.77, respectively, have been submitted to exhaustive methanolysis until the amount of the insoluble residue did not further decrease. Dissolved and insoluble material were determined gravimetrically and further analyzed with respect to their substituent distribution in the glucosyl units by capillary electrophoresis, and by size exclusion chromatography. While the substitution of the soluble fraction was slightly above the average DS and in accordance with a random distribution (Spurlin), unsubstituted glucose was steadily enriched in the retained solid material (10 and 20 mol%), resulting in a final DS of 0.46 and 0.42, respectively. An “excess” of unsubstituted glucose is mainly responsible for the heterogeneity of this portion, since deviation from the Spurlin model could be minimized by reducing the molar fraction of glucosyl units. Estimation of the DS/DP-distribution profile of the insoluble residue from molar mass and substituent distribution data, and comparison with the profile of the original CMC (DS 0.75) showed that roughly only about half of the residue could be covered by sequences of the original CMC if random substitution is assumed. This indicates that there is a certain portion of unsubstituted domains in a low substituted heterogeneous part of the CMC. By this procedure, low or unsubstituted areas as a minor part of the CMC material can be concentrated and heterogeneity detected with higher sensitivity.

Physicochemical characterization and study of molar mass of industrial gelatins by AsFlFFF-UV/MALS and chemometric approach.

Industrial gelatins have different physicochemical properties that mainly depend of the raw materials origin and the extraction conditions. These properties are closely related to the molar mass distribution of these gelatins. Several methods exist to characterize molar mass distribution of polymer, including the Asymmetrical Flow Field Flow Fractionation method. The goal of this study is to analyze the relationship between physicochemical properties and the gelatins molar mass distribution obtained by Asymmetrical Flow Field Flow Fractionation. In this study, 49 gelatins samples extracted from pig skin are characterized in terms of gel strength and viscosity and their molar mass distribution are analyzed by Asymmetrical Flow Field Flow Fractionation coupled to an Ultraviolet and Multi Angle Light Scattering detector. This analytical method is an interesting tool for studying, simultaneously, the primary chains and the high-molar-mass fraction corresponding to the polymer chains. Correlation analysis between molar mass distribution data from the different fractions highlights the importance of high molar mass polymer chains to explain the gel strength and viscosity of gelatins. These results are confirmed by an additional chemometric approach based on the UV absorbance of gelatin fractograms to predict gel strength (r2Cal = 0.85) and viscosity (r2Cal = 0.79).

Two topics on charmonium-like states

Two topics about the charmonium-like spectrum are discussed here. In the first part, we present that in a combined analysis of γγ→DD‾, J/ψω processes the X(3915) is preferred to be the same tensor state as the X(3930) by the experiment data. In the second part, we show that, in a coupled-channel unitarized model, the mass distribution data sets of X(4260)→J/ψπ+π−, (DD⁎)±π∓, (D⁎D⁎)±π∓ could be described perfectly at the same time. By analyzing the singularity structure of the amplitudes, one could find that the peak of Zc(3900) line-shape is mainly contributed by a thirdsheet pole at about 3.875 ± 0.016GeV. The analysis clearly demonstrates that a good quantitative description of the mass distribution data requires the pole contribution to the Zc(3900) line-shape rather than the pure cusp effect.

Distinguishing near-threshold pole effects from cusp effects

We make use of a unitarized coupled-channel model to analyze the mass distribution data of final states in production processes of $X(4260)$. By analyzing the analytical structures of the decay amplitudes, we find that the line shape of $Z_c(3900)$ signal is related to the combined effect of a pair of near-threshold "shadow" poles and the $(D\bar{D}^*)^\pm$ thresholds, in which the third-sheet pole might provide a dominant contribution. As all the coupled channels effects are tuning off, the trajectories of these two poles suggest that the $Z_c(3900)$ might originate from the attractive interaction of $(D^*\bar{D}^*)^\pm$ through a long-distance interaction, $e.g.$ $\pi$-exchange interaction, as a "deuteron-like" state. There is no nearby pole structure corresponding to the $Z_c(4025)$ signal in the $(D^*\bar{D}^*)^\pm$ mass distribution.

Simulation of semi-crystalline polyethylene: Effect of short-chain branching on tie chains and trapped entanglements

A Monte-Carlo simulation method for assessing the tie chain and trapped entanglement concentration in linear polyethylene was extended to enable the simulation of explicitly branched polyethylene. A subroutine was added to the model making possible the incorporation of different branch lengths and distributions. In addition, the microstructure of branched polyethylene was considered to be made of lamellar stacks of different thicknesses, acknowledging the segregation phenomenon during crystallization. Also, based on complete exclusion of bulky branches from the crystal lattice, a ‘pull-out’ mechanism was developed for the relaxation of branched parts of polyethylene chains in the vicinity of the crystal layer. Simulations of two series of real polyethylene samples showed the effect of short-chain branching on the concentrations of tie chains and trapped entanglements. Introducing a few branches to an unbranched polyethylene increased the concentration of inter-lamellar connections significantly. This effect decayed if the number of branches was further increased. The tracking of the position of all the carbon atoms during the crystallization process was implemented in the model, making the average square end-to-end distance <r2> of polyethylene chains calculable. Simulation of chains with the same molar mass but with different branch contents showed a reduction in the average end-to-end distance with increased branching. The use of real molar mass distribution data was also added to the model features.

Statistics of the distribution of the abundance of molecules with various drug loads in maytansinoid antibody-drug conjugates.

The maytansinoid antibody-drug conjugates (ADCs) in clinical development for cancer therapy each contain a derivative of the microtubule-targeting agent, maytansine, covalently attached to the antibody via an engineered linker. A sample of any of these conjugates contains molecules with different numbers of maytansinoid molecules, or "drug" loads, the relative abundance of which can be determined by mass spectrometry. We examined the accuracy of the Poisson distribution and the binomial distribution in predicting the relative abundance of species with different drug loads for three antibody-maytansinoid conjugates with different antibodies and linker-maytansinoid pairings. We used variance, calculated from the experimental mass distribution data, as the parameter to determine the optimal value n of the binomial distribution number of trials. The accuracy of the Poisson distribution in predicting distribution of the species abundance in these conjugates varied among the conjugates. In contrast, the accuracy of the binomial distribution was similar for all three conjugates and comparable to the best accuracy of the Poisson distribution, as supported by a paired t-test.

Laboratory-scale extraction and characterization of ice-binding sericin peptides

Sericin peptides (SPs) are a new cryoprotectant with protecting abilities for organisms or biomacromolecule in food stuff from freezing injury in subzero environments. The extraction of ice-binding sericin peptides (I-SPs) by ice affinity extraction adsorption and their cryoprotective effect on Lactobacillus Delbrueckii Subsp. bulgaricus LB340 LYO during frozen storage was studied in this paper. The optimal extraction conditions by application of a new and assembled ice absorption apparatus were identified as temperature of −3 °C, SPs concentration of 5 mg/mL, and extraction time of 3 h. Compared with SPs, I-SPs were found to be increased in the contents of some special amino acid residues, including Ser, Thr, Gly, and Ala, which might be relative with the ice affinity as well as the cryoprotective activity of ice-structuring proteins. Meanwhile, the molecular mass distribution data implied that the free amino acids in the SPs could be excluded from the ice affinity adsorption, and peptides containing 3–6 amino acid residues might be more liable to adsorb to ice surface. Furthermore, with addition of I-SPs at concentrations of more than 0.01 mg/mL, LB340 strain had a higher survival rate after frozen storage compared to the water control as well as SPs (p < 0.05).

Estimation of a suitable Schmidt number range in diesel sprays at high injection pressure

The aim of this paper is to estimate a suitable range for the Schmidt number value in non-evaporative diesel sprays. For this purpose, mass distribution data obtained from X-ray absorption experiments existing in literature and a theoretical derivation for spray microscopic characteristics have been combined. Firstly, a procedure based on Gaussian concentration profiles has been proposed in order to interpret X-ray absorption results and relate them to physical parameters as local concentration or spray density. After this, information about FWHM (Full Width at Half Maximum) values has allowed to estimate spray angle in the tested conditions by the definition of Gaussian profiles for the mass radial distribution inside the spray. Following, a theoretical model dependent on momentum flux and Schmidt number has been used to simulate local mass concentration evolution along the spray axis and compare it with the values obtained from the experiments. The combination of the experimental and the theoretical data has allowed to estimate a suitable range for the Schmidt number value in such conditions as those existing in diesel sprays.

A permanently-acting NEA damage mitigation technique via the Yarkovsky effect

In the later stages of a combined mission of exploration and damage mitigation of a hazardous Near Earth Asteroid (NEA), sufficiently detailed tracking, orbit prediction, mass distribution, and physical properties data have been accumulated. It may be desirable to implement a “slow push” damage mitigation technique that is capable of altering the NEA orbit continuously and permanently. This possibility was suggested in a companion paper that outlined an archetypal exploration/mitigation mission to the NEA 99942 Apophis, which is achieved using a novel albedo change approach. The details and apparatus used in the albedo modification technique are described in the paper. We describe the design details and the constraints on particle size (to prevent electrostatic levitation and escape) and on the dispensing speed (to achieve the desired coverage zone and prevent particles from orbiting or escaping).

The Influence of Flow Rate on the Aerosol Deposition Profile and Electrostatic Charge of Single and Combination Metered Dose Inhalers

The capability of the electrostatic next generation impactor (eNGI) has been investigated as a tool capable of measuring the electrostatic charge of single (Flixotide; containing fluticasone propionate (FP)) and combination (Seretide; FP and salmeterol xinafoate (SX)) pressurised metered dose inhalers (pMDIs) at different flow rates. Aerosol mass distributions were investigated at 30, 60 and 90 l.min(-1) and simultaneous charge measurements recorded. Analysis of the mass distribution data indicated a flow dependent relationship, where the aerosol performance (aerodynamic diameter <5 mum) of FP significantly increased between 30 l.min(-1) and 60 l.min(-1) for both formulations. No significant increase in SX was observed for Seretide with increased flow rate. Analysis of the charge distribution indicated both formulations to primarily charge negatively with a concurrent increase in charge with increased flow rate. Interestingly, the charge-tomass ratio remained relatively constant between 30 l.min(-1) and 60 l.min(-1) and increased at 90 l.min(-1), indicating that charging was majorly influenced at the highest flow rate. This study has shown how the eNGI could be used as a simple Pharmacopeia based methodology for the evaluation of mass and charge profiles of single and combination pMDIs at a series of flow rates.

Quantitative X-ray measurements of high-pressure fuel sprays from a production heavy duty diesel injector

A quantitative and time-resolved X-ray radiography technique has been used for detailed measurements of high-pressure fuel sprays in the near-nozzle region of a diesel engine injector. The technique provides high spatial and temporal resolution, especially in the relatively dense core region. A single spray plume from a hydraulically actuated electronically controlled unit injector model 315B injector with a 6-hole nozzle was isolated and studied at engine-like densities for two different injection pressures. Optical spray imaging was also employed to evaluate the effectiveness of the shield used to isolate a single spray plume. The steady state fuel distributions for both injection pressures are similar and show a dense spray region along the axis of the spray, with the on-axis spray density decreasing as the spray progresses downstream. The higher injection pressure case exhibits a larger cone angle and spray broadening at the exit of the nozzle. For some time periods, the near-nozzle penetration speed is lower for the high injection pressure case than the low injection pressure case, which is unexpected, but can be attributed to the needle and flow dynamics inside the injector causing slower pressure build-up for the former case. Rate of injection testing was performed to further understand near-nozzle behavior. Mass distribution data were obtained and used to find mass-averaged velocity of the spray. Comparisons of the radiography data with that from a common rail single-hole light duty injectors under similar injection conditions show several significant differences. The current data show a larger cone angle and lower penetration speed than that from the light-duty injector. Moreover, these data display a Gaussian mass distribution across the spray near the injector, whereas in previous light-duty injector measurements, the mass distribution had steeper sides and a flatter peak. Measurements are also used to examine the spray models in the STAR-CD software.

Systematics on fission fragment mass distribution of neutron induced 235U fission

Based on the neutron induced fission fragment mass distribution data up to neutron energy 20 MeV measured with the double kinetic energy method (KEM) and the radio active method (RAM), the systematics of fission fragment mass distribution was investigated by using 5 Gaussian model and the systematics parameters were obtained by fitting the experimental data. With the systematics, the yields of any mass A and at any energy in the region from 0 to 20 MeV of neutron energy can be calculated. The calculated results could well reproduce the experimental data measured with KEM, but show some systematical deviation from the data measured by RAM, which reflects some systematical deviations between the two kinds of measured data.The error of systematics yield was calculated in an exact error transformation way, including from the error of the experimental yield data to the error of the discrete parameters, then to the systematics parameters, and at last to the yield calculated with systematics.

Controlled CCVD Synthesis of Robust Multiwalled Carbon Nanotube Films

The emerging interest toward applications of robust highly aligned carbon nanotube forests requires synthesis of such films in a controlled manner. In this paper, the growth mechanism and influence of growth parameters on the structural properties of multiwalled carbon nanotube films grown by catalytic chemical vapor deposition on SiO2 surfaces are investigated. The experimental studies are complemented with computational finite element simulations of temperature and flow fields in the reactor to have a better understanding on tailored synthesis. Film thickness, mass, density, purity, alignment, and nanotube size distribution data were assessed as a function of several growth parameters by electron microscopy and electron and X-ray diffraction techniques.

Polyhydroxyalkanoate production from whey by Pseudomonas hydrogenovora

Whey permeate from dairy industry was hydrolyzed enzymatically to cleave its main carbon source, lactose, to glucose and galactose. The hydrolysis products were chosen as carbon sources for the production of poly-3-hydroxybutyric acid (PHB) by Pseudomonas hydrogenovora. In shaking flask experiments, the utilization of whey permeate as a cheap substrate was compared to the utilization of pure glucose and galactose for bacterial growth under balanced conditions as well as for the production of PHB under nitrogen limitation. After determination of the inhibition constant K i for sodium valerate on biomass production ( K i = 1.84 g/l), the biosynthesis of PHA co-polyesters containing 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) units from hydrolyzed whey permeate and valerate was investigated. The application of hydrolyzed whey permeate turned out to be advantageous compared with the utilization of pure sugars. Therefore, fermentation under controlled conditions in a bioreactor was performed with hydrolyzed whey permeate to obtain detailed kinetic data (maximum specific growth rate, μ max = 0.29 1/h, maximum polymer concentration, 1.27 g/l PHB), values for molecular mass distribution (weight average molecular weight M w = 353.5 kDa, polydispersity index PDI = 3.8) and thermo analytical data. The fermentation was repeated with co-feeding of valerate (maximum specific growth rate, μ max = 0.20 1/h, maximum polymer concentration, 1.44 g/l poly-(3HB- co-21%-3HV), weight average molecular weight M w = 299.2 kDa, polydispersity index PDI = 4.3).

Application of Heated Inlet Extensions to the TSI 3306/3321 System: Comparison with the Andersen Cascade Impactor and Next Generation Impactor

Pharmaceutical aerosol size distribution analysis based on multi-stage inertial impaction is well accepted, though laborious. The TSI 3306 Impactor Inlet/3321 time-of-flight (TOF) Aerodynamic Particle Size Analyzer (APS) has been evaluated for its ease of use and potential for time savings during product development. However, instrument inlet modifications may be necessary for increased correlation with equivalent measurements obtained by inertial impaction following pharmacopeial methods. A heated inlet extension tube was located between the USP/Ph.Eur. throat and the Single-Stage Impactor (SSI) to promote evaporation of residual ethanol from aerosol droplets, generated from two formulations containing ethanol as semi-volatile solubilizer (8 and 20% w/w) for the active pharmaceutical ingredient. As temperature and extension length increased, the SSI-measured fine particle fraction (aerosol < 4.7 microm aerodynamic diameter) also increased, for the aerosols used in this study. These values correlated quite closely with equivalent measures made by multi-stage cascade impactor equipped with the same throat. Particle size distribution profiles measured with the APS for either formulation did not significantly change utilizing the heated extensions, suggesting that ethanol evaporation was largely complete at any condition by the time the aerosol entered the measurement zone of the TOF analyzer. The addition of a heated inlet extension may be useful to facilitate evaporation of residual semi-volatile species, especially when an agreement of APS-derived particle size mass distribution data from the SSI with multi-stage cascade impactors is desired. However, complete evaporation of the semi-volatile species may not be necessary for SSI-generated mass distribution to match conventionally used cascade impactors.

Determination of metabolic flux changes during fed-batch cultivation from measurements of intracellular amino acids by LC-MS/MS

Metabolic flux analysis using (13)C-labeled substrates is a well-developed method for investigating cellular behavior in steady-state culture condition. To extend its application, in particular to typical industrial conditions, such as batch and fed-batch cultivations, a novel method of (13)C metabolic flux analysis is proposed. An isotopomer balancing model was developed to elucidate flux distributions in the central metabolism and all amino acids synthetic pathways. A lysine-producing strain of Escherichia coli was cultivated by fed-batch mode in a growth medium containing yeast extract. Mass distribution data was derived from both intracellular free amino acids and proteinogenic amino acids measured by LC-MS/MS, and a correction parameter for the protein turnover effect on the mass distributions of intracellular amino acids was introduced. Metabolic flux distributions were determined in both exponential and stationary phases. Using this new approach, a culture phase-dependent metabolic shift was detected in the fed-batch culture. The approach presented here has great potential for investigating cellular behavior in industrial processes, independent of cultivation modes, metabolic phase and growth medium.