Fractional Loss Research Articles

Agrogena evolucija humusno-podzolastog zemljišta - mogućnost ponovnog uključivanja u obradu ugara formiranog na trakastim glinama

Transformations of the soddy-podzolic gleyic clay soil in a long-term agricultural use (> 200 years) was studied in Leningrad region, northwest Russia. This feasibility study investigated the possibility of re-cultivation of these soils after long term fallowing. Morphological structure, particle size distribution, content and ratio of ferrous and oxide forms of iron in the profile of virgin (indigenous forest) and arable drained soil were analysed. In addition, changes in the organogenic-profile were traced in the course of long-term agrogenesis (> 200 years). In virgin forest soil, during its pedogenesis the loss of fractions <0.01 mm from the eluvial layer was 877.4 kg m-2 , and the loss of <0.0001mm was 287.5 kg m-2 , as compared with parent material not affected by the processes of pedogenesis. However, long-term agrogenesis (>200 years) led to increased eluvial losses of fine earth particles. The loss of fraction <0.01 mm from the arable horizons was 1244.8, and < 0.0001 mm was 570 kg m-2 , respectively. This was due to multiple yearly tillage that increased the porosity of the soil and thus intensified lessivage, which led to increased leaching and eluvial losses. The total loss of colloids from the entire profile of virgin soil was 262.1 kg m-2 , and from the arable layer of drained soil - 290.1 kg m-2 . The humus enrichment of the colloids of the plough (P) horizon of the arable soil was two times lower than that of the surface (AY) horizon of the virgin soil. The relative share of the participation of colloids in the fixation of humus by the soil was the same (11.6 and 10.9%, respectively). In the subsurface horizons, the absolute content of humus in the colloids decreased, and the share of participation in the fixation of humus increased. When soddy-podzolic gleyic clay soil is brought to cultivation then the water-air regime is improved, content and composition of humus, depth of arable horizon is increased and the soil acidity decreased. At the same time the leaching of fine earth materials is accelerated. When this soil was withdrawn from crop production, the positive changes achieved as a result of cultivation were gradually lost. For the first time we could qualitatively calculate the losses of the fine earth fractions for the given soil from top soil. Taking into account the high costs of re-cultivation of the former land and a high cost of re-installation and maintenance of an optimal hydrological regime (drainage network) we concluded that repeated ploughing and involvement of arable soddy-podzolic gleyic clay soil into cultivation is economically unreasonable.

Evaluation of the electron transport algorithm in magnetic field in EGS5 Monte Carlo code.

To evaluate the accuracy of electron transport in the magnetic field of Electron Gamma Shower version 5 (EGS5) by using the special Fano cavity test. To simulate electron transport in the magnetic field, the trajectory of the electron was reconstructed with a short step length to restrict fractional energy loss, and the maximum user step length (mxustep) was set at 0.01cm or 0.001cm. For the special Fano cavity test, three-layer slab Fano test geometry was used, and uniform and isotropic per unit mass mono-energetic electrons with 0.01, 0.1, 1.0, and 10MeV were permitted from the central axis of geometry in 0.35T and 1.5T. Furthermore, the magnetic field strength was scaled based on the mass density of the material. The relative difference between the calculated dose to gap and the theoretical value was evaluated. Furthermore, the special Fano cavity test was also performed using EGSnrc with the electron-enhanced electric and magnetic field macros under the same conditions, and the results were compared with those of EGS5. Deviations in 0.35T were within 0.3% regardless of the parameter settings. In 1.5T, stable results within 0.3% were obtained using 0.001cm as the mxustep, except for one at 10MeV. Further, the accuracy of EGSnrc was within 0.2%, except for 10MeV for a 0.2-cm gap in 1.5T. EGS5 with the appropriate parameter settings enable electron transport in magnetic fields similar with the accuracy of EGSnrc.

Determination of quality indicators of marmalade with addition of multi-component fruit and berry paste during storage

The object of research is the technology of jelly-fruit marmalade with the addition of multicomponent fruit and berry paste from apples, quince and black currant. Marmalade products are in demand due to their attractive appearance, excellent taste, aroma and good absorption by the body. This delicacy is characterized by the absence of fat, high sugar content and the presence of functionally physiological ingredients. Due to the growing interest of consumers in products of increased nutritional value, the technology of jelly-fruit marmalade with the addition of multicomponent fruit and berry paste from apples, quince and black currant has been improved. New confectionery products must first of all be safe for human health, therefore, organoleptic, physicochemical and microbiological indicators of the quality of marmalade were determined during storage. In terms of organoleptic quality indicators, both control and experimental marmalade samples have high quality indicators during the shelf life. The storage duration affects the consistency of the marmalade, which becomes protracted after 3 months of storage and contributes to a decrease in the color saturation of all samples. The loss of the mass fraction of moisture in the control sample of marmalade up to 6.1 % and the sample with fruit and berry paste – up to 5.0 %, an increase in acid accumulation by 4.0–20.6 % for the control and by 4.0–20 % for the sample marmalade with pasta. It is noted that the content of reducing substances increases in the control sample by 18.0–50.0 %, which is 11.8–15.0 %, and in the sample with the addition of paste – by 10.8–36.9 %, which is 12.3–15.2 %. The data obtained is admissible and meets the established quality requirements in accordance with the requirements of regulatory documents. Microbiological quality indicators have been determined and it has been established that new samples of marmalade with multicomponent paste, both freshly prepared and after a guaranteed shelf life, comply with the standards of all current requirements for the quality of food products. The safety of jellied fruit marmalade on agar with the addition of multicomponent fruit and berry paste from apples, quince and black currant has been proven during the guaranteed shelf life of 3 months.

A virtual chemistry model for soot prediction in flames including radiative heat transfer

Modeling soot formation is a very difficult task which has been assessed by the numerical combustion community. Numerical simulations of turbulent sooting flames remain very challenging due to the complexity of soot formation phenomena, which implies development of elaborate soot models often too computationally demanding, or simplified soot models that are limited to a small range of operating conditions of interest. Here an innovative optimized global approach called virtual chemistry is proposed. It consists of a mathematical formalism including virtual species and virtual reactions, whose thermochemical parameters are optimized in order to describe a combustion system. Thermochemical properties are trained through a genetic algorithm, employing a learning database made of reference flame elements. This makes it possible to reproduce multiple combustion regimes and operating conditions. The virtual chemistry approach reproduces then the structure of hydrocarbon-air flames, as well as predicting specific user-defined pollutant species. The objective of this article is to extend the virtual chemistry methodology for soot formation prediction. As the radiative heat losses are important in sooting flames, a new radiative virtual model is also developed to account for them. The final reduced chemistry consists of 12 virtual species and 6 virtual reactions considerably decreasing the computational time compared to detailed chemistry models. Simulations of 1-D and 2-D laminar ethylene-air sooting flames are performed to evaluate the virtual soot and radiative models. Temperature, soot volume fraction and radiative heat losses are well predicted and are in good agreement with the reference data.

Beam-beam interaction in a dielectric laser accelerator electron-positron collider

We examine through numerical calculation the collision of counter-propagating trains of optically spaced electron or positron microbunches in a 1 TeV collider scenario for a dielectric laser accelerator. A time-dependent envelope equation is derived for arbitrary number of bunches in the classical limit, with inclusion of the radiation reaction force. Example parameters are examined based on a constrained luminosity relation that takes into account the bunch charge for optimal efficiency, material damage limits, and power constraints. We find that for initially identical counter-propagating Gaussian bunch trains, the periodic temporal structure leads to a peak in luminosity with number of bunches. For longer bunch trains, the enhancement then decreases inversely with number of bunches. The corresponding fractional energy loss of the beam is found to be of order 1.75%, which is reduced to 0.35% when the nonlinear radial dependence of the transverse force is included, with an average beamstrahlung parameter of 0.075, an important result considering that beamstrahlung losses are a critical concern for future TeV colliders.

Kinetic modelling of dissolution dynamic nuclear polarisation 13 C magnetic resonance spectroscopy data for analysis of pyruvate delivery and fate in tumours.

Dissolution dynamic nuclear polarisation (dDNP) of 13 C-labelled pyruvate in magnetic resonance spectroscopy/imaging (MRS/MRSI) has the potential for monitoring tumour progression and treatment response. Pyruvate delivery, its metabolism to lactate and efflux were investigated in rat P22 sarcomas following simultaneous intravenous administration of hyperpolarised 13 C-labelled pyruvate (13 C1 -pyruvate) and urea (13 C-urea), a nonmetabolised marker. A general mathematical model of pyruvate-lactate exchange, incorporating an arterial input function (AIF), enabled the losses of pyruvate and lactate from tumour to be estimated, in addition to the clearance rate of pyruvate signal from blood into tumour, Kip , and the forward and reverse fractional rate constants for pyruvate-lactate signal exchange, kpl and klp . An analogous model was developed for urea, enabling estimation of urea tumour losses and the blood clearance parameter, Kiu . A spectral fitting procedure to blood time-course data proved superior to assuming a gamma-variate form for the AIFs. Mean arterial blood pressure marginally correlated with clearance rates. Kiu equalled Kip , indicating equivalent permeability of the tumour vasculature to urea and pyruvate. Fractional loss rate constants due to effluxes of pyruvate, lactate and urea from tumour tissue into blood (kpo , klo and kuo , respectively) indicated that T1 s and the average flip angle, θ, obtained from arterial blood were poor surrogates for these parameters in tumour tissue. A precursor-product model, using the tumour pyruvate signal time-course as the input for the corresponding lactate signal time-course, was modified to account for the observed delay between them. The corresponding fractional rate constant, kavail , most likely reflected heterogeneous tumour microcirculation. Loss parameters, estimated from this model with different TRs, provided a lower limit on the estimates of tumour T1 for lactate and urea. The results do not support use of hyperpolarised urea for providing information on the tumour microcirculation over and above what can be obtained from pyruvate alone. The results also highlight the need for rigorous processes controlling signal quantitation, if absolute estimations of biological parameters are required.

(U‐Th)/He and 4He/3He Thermochronology of Secondary Oxides in Faults and Fractures: A Regional Perspective From Southeastern Arizona

AbstractFe‐ and Mn‐oxides are common secondary minerals in faults, fractures, and veins and potentially record information about the timing of fluid movement through their host rocks. These phases are difficult to date by most radioisotopic techniques, but relatively high concentrations of U and Th make the (U‐Th)/He system a promising approach. We present new petrographic, geochronologic and thermochronologic analyses of secondary oxides and associated minerals from fault zones and fractures in southeastern Arizona. We use these phases in attempt to constrain the timing of fluid flow and their relationship to magmatic, tectonic, or other regional processes. In the shallowly exhumed Galiuro Mountains, Fe‐oxide (U‐Th)/He dates correspond to host‐rock crystallization and magmatic intrusions from ca. 1.6 to 1.1 Ga. Step‐heating 4He/3He experiments and polydomain diffusion modeling of 3He release spectra on these samples are consistent with a crystallite size control on He diffusivity, and little fractional loss of radiogenic He since formation in coarse‐grained hematite, but large losses from fine‐grained Mn‐oxide. In contrast to Proterozoic dates, Fe‐ and Mn‐oxides from the Catalina‐Rincon and Pinaleño metamorphic core complexes are exclusively Cenozoic, with dates clustering at ca. 24, 15, and 9 Ma, which represent distinct cooling or fluid‐flow episodes during punctuated periods of normal faulting. Finally, a subset of Fe‐oxides yield dates of ca. 5 Ma to 6 ka and display either pseudomorphic cubic forms consistent with oxidative retrogression of original pyrite or magnetite, or fine‐grained botryoidal morphologies that we interpret to represent approximate ages of recrystallization or pseudomorphic replacement at shallow depths.

Implication of Vestibular Hair Cell Loss of Planar Polarity for the Canal and Otolith-Dependent Vestibulo-Ocular Reflexes in Celsr1-/- Mice.

Introduction: Vestibular sensory hair cells are precisely orientated according to planar cell polarity (PCP) and are key to enable mechanic-electrical transduction and normal vestibular function. PCP is found on different scales in the vestibular organs, ranging from correct hair bundle orientation, coordination of hair cell orientation with neighboring hair cells, and orientation around the striola in otolithic organs. Celsr1 is a PCP protein and a Celsr1 KO mouse model showed hair cell disorganization in all vestibular organs, especially in the canalar ampullae. The objective of this work was to assess to what extent the different vestibulo-ocular reflexes were impaired in Celsr1 KO mice.Methods: Vestibular function was analyzed using non-invasive video-oculography. Semicircular canal function was assessed during sinusoidal rotation and during angular velocity steps. Otolithic function (mainly utricular) was assessed during off-vertical axis rotation (OVAR) and during static and dynamic head tilts.Results: The vestibulo-ocular reflex of 10 Celsr1 KO and 10 control littermates was analyzed. All KO mice presented with spontaneous nystagmus or gaze instability in dark. Canalar function was reduced almost by half in KO mice. Compared to control mice, KO mice had reduced angular VOR gain in all tested frequencies (0.2–1.5 Hz), and abnormal phase at 0.2 and 0.5 Hz. Concerning horizontal steps, KO mice had reduced responses. Otolithic function was reduced by about a third in KO mice. Static ocular-counter roll gain and OVAR bias were both significantly reduced. These results demonstrate that canal- and otolith-dependent vestibulo-ocular reflexes are impaired in KO mice.Conclusion: The major ampullar disorganization led to an important reduction but not to a complete loss of angular coding capacities. Mildly disorganized otolithic hair cells were associated with a significant loss of otolith-dependent function. These results suggest that the highly organized polarization of otolithic hair cells is a critical factor for the accurate encoding of the head movement and that the loss of a small fraction of the otolithic hair cells in pathological conditions is likely to have major functional consequences. Altogether, these results shed light on how partial loss of vestibular information encoding, as often encountered in pathological situations, translates into functional deficits.

On the Similarity and Repeatability of Fast Radiation Belt Loss: Role of the Last Closed Drift Shell

AbstractProperly characterizing fast relativistic electron losses in the terrestrial Van Allen belts remains a significant challenge for accurately simulating their dynamics. In particular, magnetopause shadowing losses can deplete the radiation belt within hours or even minutes, but can have long‐lasting impacts on the subsequent belt dynamics. By statistically analyzing seven years of data from the entire Van Allen Probes mission in the context of the last closed drift shell, here we show how these losses are much more organized and predictable than previously thought. Once magnetic storm electron dynamics are properly analyzed in terms of the location of the last closed drift shell, not only is the loss shown to be repeatable but its energy‐dependent spatio‐temporal evolution is also revealed to follow a very similar pattern from storm to storm. Employing an energy‐dependent ULF wave radial diffusion model, we further show for the first time how the similar and repeatable fractional loss of the pre‐storm electron population in each storm can be reproduced and explained. Empirical characterization of this loss may open a pathway toward improved radiation belt specification and forecast models. This is especially important since underestimates of loss can also create unrealistic sources in models, creating phantom electron radiation and leading to the prediction of an overly harsh radiation environment.

Experiments with colliding rods

When a short rod collides end-on with a long rod, kinetic energy is not conserved since the longer rod vibrates after the collision. In theory, the fractional energy loss is equal to 1 − L 1/L 2 where L 1 is the length of the short rod, L 2 is the length of the long rod, and the long rod is initially at rest. Measurements of the energy loss are presented for a set of steel rods and a set of wood dowels. The steel rods were shorter than the dowels and behaved more like steel balls, with only a small decrease in kinetic energy. A larger fractional energy loss was observed when using the dowels since a larger fraction of the initial kinetic energy was converted to vibrational energy in the dowels. In neither case was the energy loss equal to 1 − L 1/L 2.

A Novel Dehumidification Strategy to Reduce Liquid Fraction and Condensation Loss in Steam Turbines.

Massive droplets can be generated to form two-phase flow in steam turbines, leading to erosion issues to the blades and reduces the reliability of the components. A condensing two-phase flow model was developed to assess the flow structure and loss considering the nonequilibrium condensation phenomenon due to the high expansion behaviour in the transonic flow in linear blade cascades. A novel dehumidification strategy was proposed by introducing turbulent disturbances on the suction side. The results show that the Wilson point of the nonequilibrium condensation process was delayed by increasing the inlet superheated level at the entrance of the blade cascade. With an increase in the inlet superheated level of 25 K, the liquid fraction and condensation loss significantly reduced by 79% and 73%, respectively. The newly designed turbine blades not only remarkably kept the liquid phase region away from the blade walls but also significantly reduced 28.1% averaged liquid fraction and 47.5% condensation loss compared to the original geometry. The results provide an insight to understand the formation and evaporation of the condensed droplets inside steam turbines.

Shake loss intensities in x-ray photoelectron spectroscopy: Theory, experiment, and atomic composition accuracy for MgO and related compounds

The relative intensities of XPS core levels, scaled by their photoionization cross sections, are regularly used to determine sample atomic composition. Cross sections, however, give the intensity to all possible final states for the core ionizations, not just to the main peak. This includes all intrinsic satellite structure (shake states and, for open shell systems, the different ionic multiplets). In practice, for solids, this is usually experimentally impossible to determine accurately because such a satellite structure sits on the inelastically scattered electron background and cannot be easily separated. Therefore, usually, only the intensity of the main peak is used. This limits the ultimate possible accuracy of XPS composition determination. The purpose of the present paper is to examine the contributions that a theoretical analysis of losses of intensity can make to improve quantitation. For an MgO single crystal, we show that the correct stoichiometry of 1:1 can be recovered using the theoretical analysis of the experimental MgO peak ratio intensities. For materials with a sufficient bandgap for the XPS main peaks to be separated from the scattered background, the intensity of main peaks can often be accurately determined. Thus, if one uses theory to calculate that fraction of the total intensity lost from a main peak into all its satellite structure, the intensity of just main peaks could then be used to more accurately determine relative atom % composition. This work tests this approach using a single crystal MgO (50% Mg, 50% O) standard. Ab initio electronic structure theory of representative MgO clusters is used to determine Hartree–Fock wave functions for the ground state and final ionized states corresponding to the main Mg 2p and O1s XPS peaks of the oxide. The sudden approximation, SA, is used to determine the fractional losses from these main peaks to shake satellites, which is found to be greater for O1s than Mg2p. This results in predicted “apparent composition” for stoichiometric MgO of 55.2% Mg, 44.8% O instead of the true 50% Mg, 50% O. Equivalent theory for CaO results in a predicted apparent Ca value of 53.4%. Experimentally, using Mg2s or 2p intensity ratio to O1s, we find values between 52.2% and 56.0% Mg using two crystals and four different instrument electron pass energies. The average value of the measurements is 54.5% Mg when corrected for the presence of an adventitious carbon overlayer and slight surface hydroxide. Though this agreement with theory may be somewhat fortuitous, given the potential experimental errors, which are fully discussed, it is similar to that in our earlier study on LiF. We also present preliminary experimental data on Mg(OH)2 and MgSO4, which show a similar trend of apparently higher than 50% Mg, but we have no theory values. We are not yet able to experimentally test for validation of the difference between apparent composition for MgO (55.2% Mg) and CaO (53.4% Ca), owing to significant carbonate formation at the surface of the single crystal CaO. An important conclusion is that the theoretical determination of shake losses, obtained with ab initio wavefunctions and the SA, is likely to be a useful way to calibrate the accuracy and reliability of compositions obtained from XPS intensities and merits further study.

Can a complex ecosystem survive the loss of a large fraction of its species? A random matrix theory of secondary extinction

Recent estimates suggest that a quarter of species globally are under threat of extinction. Understanding what happens to ecological networks of interacting organisms when they lose a significant fraction of species is thus essential for assessing, and potentially mediating, the current biodiversity crisis. We introduce and explore a framework for studying the repercussions of mass extinctions in large model ecosystems. This random‐matrix approach reveals the statistical properties of the post‐extinction abundances to exhibit a simple structure, allowing us to determine analytically how susceptibility to secondary extinctions depends on the strength and nature of interspecies interaction. We find, for example, that mutualistic networks are particularly sensitive to species loss and that, for small primary extinctions, realistic food webs suffer fewer secondary extinctions than do random ones. Finally we show how the response to low‐level extinctions can be used to predict the effects of more severe events.

Experimental models of orthodontic tooth movement and their effects on periodontal tissues remodelling

ObjectivesThe present study aimed to compare two different models of orthodontic tooth movement (OTM) in rats by evaluating tooth movement efficiency and periodontal tissues remodelling. DesignFifteen animals were randomly distributed into 3 groups: control group (untreated); ligature appliance (LA) as experimental OTM using a closed coil spring fixed around maxillary first molar by steel ligature; occlusal appliance (OA) as experimental OTM using a closed coil spring attached on the occlusal surface of the maxillary first molar. After 15 days, all animals were euthanized, and the maxilla of each animal was collected for qPCR, micro-computed tomography, and histological analyses. ResultsInterleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha gene expressions were significantly upregulated in the animals of the LA group as compared to the other groups. No significant difference was observed in tooth displacement between both methods. The LA group presented higher linear bone loss and lower values of bone volume fraction, bone mineral density, trabecular number and increased values of trabecular separation compared to the other groups. The birefringent collagen content in the tension side of the periodontal ligament contained significantly lower collagen content in the LA group than in the control group. Furthermore, on the pressure side, the collagen content was significantly lower in the LA and OA groups than in the control group. ConclusionsThe OA group presented little or no deleterious effect on periodontal tissues compared to the LA group, suggesting its use may be more reliable for OTM induction in rats for 15 days.

A thorough three-dimensional simulation of steam generating solar parabolic trough collectors, a benchmark of various methods’ accuracy

Investigations show that most simulations on solar parabolic trough collectors reported in the literature are one-dimensional or at least with a variety of simplifications. Indeed, for this collector type, due to the complex heat transfer elements as well as two-phase flow through the tubes, etc., such simplifications make the model fail to give an acceptable estimation of the circumferential temperature distribution of the walls, thermal stresses, heat losses, vapor volume fraction, etc. In this article, a detailed three-dimensional numerical modeling of solar parabolic trough collectors is presented. The results of this model are also compared to those given by an axisymmetric model and a one-dimensional nodal model to highlight the impacts of such a rigorous model on the accuracy of the final results. The results demonstrated that although the axisymmetric and nodal models show acceptable accuracy in predicting the temperature and enthalpy for the flow, they are quite incapable of precisely calculating the vapor volume fraction and heat loss rates. The discrepancy in the distribution of vapor volume fraction in different sections of the absorber tube causes significant temperature heterogeneity in the solid walls.

Fossil Corals With Various Degrees of Preservation Can Retain Information About Biomineralization-Related Organic Material

Scleractinian corals typically form a robust calcium carbonate skeleton beneath their living tissue. This skeleton, through its trace element composition and isotope ratios, may record environmental conditions of water surrounding the coral animal. While bulk unrecrystallized aragonite coral skeletons can be used to reconstruct past ocean conditions, corals that have undergone significant diagenesis have altered geochemical signatures and are typically assumed to retain insufficient meaningful information for bulk or macrostructural analysis. However, partially recrystallized skeletons may retain organic molecular components of the skeletal organic matrix (SOM), which is secreted by the animal and directs aspects of the biomineralization process. Some SOM proteins can be retained in fossil corals and can potentially provide past oceanographic, ecological, and indirect genetic information. Here, we describe a dataset of scleractinian coral skeletons, aged from modern to Cretaceous plus a Carboniferous rugosan, characterized for their crystallography, trace element composition, and amino acid compositions. We show that some specimens that are partially recrystallized to calcite yield potentially useful biochemical information whereas complete recrystalization or silicification leads to significant alteration or loss of the SOM fraction. Our analysis is informative to biochemical-paleoceanographers as it suggests that previously discounted partially recrystallized coral skeletons may indeed still be useful at the microstructural level.

Commissioning and initial heating results of the neutral beam injection system in Versatile Experiment Spherical Torus

The initial neutral beam heating experiment in Versatile Experiment Spherical Torus (VEST) has been conducted via neutral beam characterizations such as neutralization efficiency, beam fraction, and shine-through loss. For the neutralization efficiency and shine-through loss estimation, a secondary electron emission (SEE) detector, which can be used in rapidly changing plasma, has been developed. The measurement results of the monatomic fraction by Doppler shift spectroscopy and the neutralization efficiency by SEE detector are 65%, and 70%, respectively. The shine-through loss measurement shows that the injection of a 12 keV neutral beam into a typical ohmic discharge of VEST results in a large amount of shine-through loss. To reduce the shine-through loss, a new target plasma discharge (0.17 T, 120 kA, 13 ms) with increased plasma density of ~2×1019m−3 is developed by providing additional gas injection. The electron-heating effect has been successfully observed for this target plasma with a 200 kW neutral beam injection at the beam energy of 12 keV. The electron temperature increases from 20 to 68 eV without significant density change when the neutral beam is injected.

Thermal oxidation characteristics for smoke particles from an abused prismatic Li(Ni0.6Co0.2Mn0.2)O2 battery

Smoke particles form a major component of flammable and toxic emissions from a failed battery. Insight into smoke-particle ignition mechanisms and reactions with air can provide a better basis for analyzing thermal hazards. This paper reports studies of thermal abusive tests for a 50-Ah prismatic Li(Ni0.6Co0.2Mn0.2)O2 battery in an inert experimental atmosphere without fire or any spark spots. By combined thermogravimetic (TG), differential thermal analysis (DTA), and Fourier transform infrared (FTIR) tests, the thermal oxidation characteristics and oxidizability of smoke particles have been analyzed and assessed. The results show marked size effects on the thermal oxidizability of the particles, which are divided into five samples by size. Fine particles suffer greater fractional mass loss fraction than coarse particles, also a larger mass transformation rate, greater absorption peak for CO2, a smaller value of differential thermal gravimetric curve, and higher enthalpy. These characteristics can be attributed to the fact that specific surface area gets larger as particle size becomes smaller. This work deepens the understanding of the ignition mechanism for smoke particles and provides references for battery system fire risk assessment and its hazard prevention.

Dynamics of Bacterial Signal Recognition Particle at a Single Molecule Level.

We have studied the localization and dynamics of bacterial Ffh, part of the SRP complex, its receptor FtsY, and of ribosomes in the Gamma-proteobacterium Shewanella putrefaciens. Using structured illumination microscopy, we show that ribosomes show a pronounced accumulation at the cell poles, whereas SRP and FtsY are distributed at distinct sites along the cell membrane, but they are not accumulated at the poles. Single molecule dynamics can be explained by assuming that all three proteins/complexes move as three distinguishable mobility fractions: a low mobility/static fraction may be engaged in translation, medium-fast diffusing fractions may be transition states, and high mobility populations likely represent freely diffusing molecules/complexes. Diffusion constants suggest that SRP and FtsY move together with slow-mobile ribosomes. Inhibition of transcription leads to loss of static molecules and reduction of medium-mobile fractions, in favor of freely diffusing subunits, while inhibition of translation appears to stall the medium mobile fractions. Depletion of FtsY leads to aggregation of Ffh, but not to loss of the medium mobile fraction, indicating that Ffh/SRP can bind to ribosomes independently from FtsY. Heat maps visualizing the three distinct diffusive populations show that while static molecules are mostly clustered at the cell membrane, diffusive molecules are localized throughout the cytosol. The medium fast populations show an intermediate pattern of preferential localization, suggesting that SRP/FtsY/ribosome transition states may form within the cytosol to finally find a translocon.

Forage Quantity and Quality Dynamics Due to Weathering over the Dry Season on California Annual Rangelands

Livestock obtain forage by grazing on rangeland. In California annual rangelands, residual dry matter is commonly used to determine proper grazing levels. Rangeland forage biomass and quality can degrade dramatically during the dormant summer period. We examined 25 sites across an annual rainfall gradient (183–492 mm) over 3 contrasting rainfall yr (2015–2017) that varied from 57% to 152% of average annual precipitation. Overall fractional biomass loss was 54.4% (range = 46.5–61.5%) with greater fractional losses occurring in dry years. Biomass losses were related to the amount of peak standing crop and plant composition—both a function of annual precipitation. Fractional seasonal losses from the peak standing biomass in 2015 = 962 kg/ha (61.5% seasonal; 9.7% monthly), 2016 = 1 541 kg/ha (55.0% seasonal; 8.7%monthly) and 2017 = 1 923 kg/ha (46.5% seasonal; 7.3%, monthly). Forage quality metrics were strongly affected by summer weathering processes. Crude protein concentrations decreased by 33.6%, 27.7%, and 21.0% in 2015, 2016, and 2017, respectively. In contrast, relative concentrations of fiber and lignin (acid detergent fiber [ADF] = cellulose + lignin) and in the weathered biomass showed increases for ADF: 44.6% (2015), 32.2% (2016), and 24.1% (2017). Increased lignin varied: 3.4% in 2015, 23.9% in 2016, and 28.0% in 2017. While ADF and lignin concentrations (weathered biomass, kg/ha) increased during the weathering process, the standing stock decreased by 39.3% (ADF) and 46.6% (lignin), compared with overall weathered biomass loss of 54.4% and CP loss of 67.1%. The significant loss of aboveground biomass and forage quality as weathering processes occurred throughout the dry summer period affects livestock grazing strategies. Forage biomass and nutrient losses through the dry season should be considered when determining grazing strategies to achieve proper residual dry matter levels and nutrient supplementation regimes before the onset of the rainy season.