Qualitative Trends Research Articles

Anatomical Sciences from a translational perspective: Bibliometric analysis

In the field of human morphology, despite its growing interest in translational anatomy research, its contributions are often unknown. Scientific articles and patents are highly reliable sources of knowledge for measuring scientific progress and technology transfer. The aim of this article is a bibliometric study of the potential of anatomical translational research. Our methodological framework has consisted of a combination of the analysis of two variables: 1) academic papers, and 2) patents of anatomical scientific achievements. The established time range has been 2000-2020 and the database used The Lens (https://www.lens.org), establishing “anatomical science” as the keyword. In the systematic analysis, 11,547 scientific documents and 1,511 patent registrations have been carried out; inclusion criteria were applied to both groups to identify their quantitative and qualitative trends. Our results identified that scientific articles on translational anatomical achievements have an exponential growth rate similar to the growth of patent applications for translational anatomical sciences. The maximum number of contributions of journal articles and patents corresponds to the temporal range of 2010 and 2020, with 2020 being the most productive year; academic documents represented 54.90% and patents produced represented 45.08%, which are significant data if they are compared with the year 2000, when the respective percentages were 76.40% and 23.50%, an indicator of a clear increase in the culture of patentability and the growing interest in translational anatomical research. The records of granted patents were 747 and 487 patent applications, which are significant data for the growth of the culture of patentability as well as the quality of the patents, since those granted represent 60.40%. These results identify the strong growth of anatomical science and its interest in the transfer of scientific achievements.

Projection of future long-term Aurelia coerulea biomass variability by regional moderate-temperature-duration approach in the Bohai and Yellow Seas

As temperature is regarded as a significant environmental factor affecting the intensity and frequency of jellyfish blooms, the projection of jellyfish peak biomass variation under global warming becomes essential for disaster prevention and mitigation on long-term time scales. The jellyfish Aurelia coerulea is distributed in worldwide oceans, particularly in the Bohai and Yellow Seas (BYSs), which are productive regions with substantial economic and climatic significance and have been suffered from A. coerulea blooms. Based on the theory of how A. coerulea reacts to various experimental temperature circumstances, recent studies have been proposed to determine the qualitative trends of A. coerulea blooms in response to climate change. However, the quantitative study of future A. coerulea biomass variability is a challenging task due to the uncertainty in the numerical relation between temperature and the biomasses of A. coerulea and the difficulty in determining the biomass considering the high mobility of jellyfishes. In this paper, we develop a moderate-temperature-duration approach to solve these two problems. The temperature suitability for all key life stages of A. coerulea during pelagic and benthic processes is involved in this approach, and we identify the major life stage that determines the peak biomass variation. The projection of future peak biomass of A. coerulea in BYSs is performed based on this approach and utilizing the long-term projection results of temperature changes by 2100 using the MPI-ESM-MR model from phase 5 of the Coupled Model Intercomparison Project (CMIP5) under the RCP4.5 scenario. The results indicate that global warming can certainly lead to the increase in A. coerulea biomass in some degree. The steady state of the highest peak biomass will be achieved during 2075∼2080, with an increase of 8.4%, 5.0%, and 11.5% in the Bohai Sea, the North Yellow Sea, and the South Yellow Sea, respectively, compared to the first steady state starting in 2020 detected by the regime shift. However, the result also shows that global warming cannot consistently lead to the increase of A. coerulea peak biomass. As the temperature rises to a large extent, the duration of moderate temperature ranges for strobilation and growth may be reduced, and thus resulting in the decrease of peak biomass instead.

Radar-based measurements of the solids flow in a circulating fluidized bed

The aim of this work is to demonstrate the value of radar technology for studying experimentally the solids flows in gas-solids fluidized beds. The work presents original results regarding the solids concentration and velocity acquired in a non-intrusive manner from a cold flow model. The tailored radar setup operates at submillimeter wave frequencies (0.34THz) and can measure the location of solids with a spatial resolution of 1/8 mm−1 in the direction of the radar beam, and of 40–60 mm across the radar beam. The solids velocity in the direction of the beam propagation is determined through measurement of the Doppler shift caused by the reflection of the transmitted radar signal by solids moving in relation to the antenna. The measurements were performed in both the horizontal and vertical directions in the riser of a circulating fluidized bed (cross-sectional area of 0.45 m2 and height of 3.1 m) operated with glass beads (mean particle size of 106 µm, and particle density of 2,486 kg/m3) and using air at ambient temperature as the fluidization agent, with superficial velocities in the range of 0.3–1.3 m/s. The measurements are used to assess the validity of the technique and are not intended to characterize the unit fluid dynamically. The solids concentrations derived from the radar measurements follow the qualitative trends derived from pressure-drop measurements, resembling the expected changes that occur in the concentration profiles as the fluidization velocity increases. Concentrations in the range from 10-6 m3/m3 to 10-1 m3/m3 are measurable. In quantitative terms, for low concentrations of solids (<5·10-3 m3/m3, approximately) the radar measurements exhibited the ability to provide more consistent measurements of the solids concentration than those obtained from pressure transducers, for which the small pressure differences lead to unstable and even negative values for solids concentrations. The two measurement methods were in quantitative agreement for solids volume fractions higher than the threshold. Concentrations ≥ 1·10-1 m3/m3, though measurable, strongly attenuate the radar signal, thereby reducing the beam penetration to a depth of centimeters. For each position along the radar beam, the distribution of solids velocity measured from the Doppler effect was found to be within the expected ranges and allowed observations of solids back-mixing. The radar technique applied in this work is a promising technique for detailed characterization of the solids flow influidized beds, offering high spatial and temporal resolutions, allowing the determination of both solids velocity and concentration, and having a reasonably high penetration depth.

Multiwavelength analysis of Galactic Supernova Remnants

The origin of Galactic Cosmic Rays (CRs) and the possibility of Supernova Remnants (SNRs) being potential CR accelerators is still an open debate. The charged CRs can be detected indirectly by the γ-ray observatories through the π 0 production and consequent decay, leading to the generation of high-energy γ-rays. The goal of the study is to identify qualitative and quantitative trends in favour of hadronic scenario and search for SNRs which could be potential accelerators up to PeV energies (PeVatrons).We have performed a Multiwavelength (MWL) study using different radiative models to evaluate the hadronic contribution. The spectral energy distributions (SEDs) of selected SNRs are modeled using the Naima [1] package. Two different radiative scenarios are considered, pure leptonic and lepto-hadronic scenarios and different methods are used to evaluate their importance.This study shows that the lepto-hadronic scenario is favored for most SNRs. Two particular indicators of hadronic contribution come from the data around the π 0 production threshold and the data above a few TeV. The hard rise at the π 0 production threshold cannot be explained by leptonic processes. More data in this region would be valuable for these studies. For some SNRs, an important hadronic contribution is observed up to a few TeV, thus making them promising PeVatron candidates. In this high-energy region where the leptonic processes are expected to be suppressed, more data is required to help distinguish between the leptonic and hadronic origin of γ-ray emission. In the future, we intend to use the obtained model parameters to simulate data for CTA and assess its capability to identify PeVatrons.

An exploration of the causal structure underlying crowdfunding: theoretical findings and practical implications

PurposeCrowdfunding (CF) is a digital-financial innovation that, bypassing credit crisis, bank system rigidities and constraints of the capital market, is allowing new ventures and established companies to get the needed funds to support innovations. After one decade of research, mainly focused on relations between variables and outcomes of the CF campaign, the literature shows methodological lacks about the study of its overall behavior. These reflect into a weak theoretical understanding and inconsistent managerial guidance, leading to a 27% success ratio of campaigns. To bridge this gap, this paper embraces a “complex system” perspective of the CF campaign, able to explore the system's behavior of a campaign over time, in light of its causal loop structure.Design/methodology/approachBy adopting and following the document model building (DMB) methodology, a set of 26 variables and mutual causal relations modeled the system “Crowdfunding campaign” and a data set based on them and crafted to model the “Crowdfunding campaign” with a causal loop diagram. Finally, system archetypes have been used to link the causal loop structure with qualitative trends of CF's behavior (i.e. the raised capital over time).FindingsThe research brought to 26 variables making the system a “Crowdfunding campaign.” The variables influence each other, thus showing a set of feedback loops, whose structure determines the behavior of the CF campaign. The causal loop structure is traced back to three system archetypes, presiding the behavior in three stages of the campaign.Originality/valueThe value of this paper is both methodological and theoretical. First, the DMB methodology has been expanded and reinforced concerning previous applications; second, we carried out a causation analysis, unlike the common correlation analysis; further, we created a theoretical model of a “Crowdfunding Campaign” unlike the common empirical models built on CF platform's data.

A Scientometric Visualization of 32 Years of Leukemia Research in India

ABSTRACT A scientometric study examines the publication’s quantitative and qualitative trends in a particular research area. The present study investigates 2,854 leukemia research outputs of India published from 1989 to 2020, indexed in the Web of Science Core Collection database. Software, including bibliometrix Biblioshiny, BibExcel, HistCite and VOSviewer, have been used for data analysis. The Pediatric Blood & Cancer journal has the highest number of published articles. The USA collaborated with the highest number of publications with India. The All India Institute of Medical Sciences had the maximum number of publications. Bakshi S, Sharma A and Varma N were the leading authors of publications about leukemia research in India. Keyword analysis revealed that acute lymphoblastic leukemia, chronic myeloid leukemia, leukemia, acute myeloid leukemia and apoptosis were the main research hotspots in the area in all publications. The Department of Biotechnology (DBT), India and the National Institute of Health (NIH), USA, were the major funders in the leukemia research publications in India. The limitation of the study is that the data used is entirely dependent on the Web of Science (WoS) Core Collection database. So, the quality of the study is entirely dependent on the input information imported from the WoS database.

Towards a predictive, physics-based friction model for the dynamics of jointed structures

Bolted connections are ubiquitous in mechanical designs and pose a significant challenge to understanding and predicting the vibration response of assembled structures. The present paper develops a physics-based rough contact model of the frictional interactions within a joint. This model sums over the probable interactions of asperities – defined as locally maximum surface features – to determine the contact forces. Here, the tangential contact forces vary smoothly between sticking and slipping and allow the model to better capture the qualitative trends of experimental amplitude dependent frequency and damping than previous studies. Furthermore, the novel model is generalized to allow for arbitrarily varying normal pressure including potential separation to better represent the interfacial dynamics. This includes developing a new, computationally tractable approximation to the analytical Mindlin partial slip solution for tangential loading of contacting spheres. The results highlight the importance of accurately characterizing the as-built topology of the interface, the plastic behavior of the contacting asperities, the relevant length scale of asperities, and the eccentricity of asperities. A predictive friction coefficient based on plasticity provides a poor match to experiments, so fitting the friction coefficient is also considered. Numerical results are compared to experiments on the Brake-Reuß Beam to assess the predictive potential of the models. While blind predictions over-predict the slip limit, the current model presents a significant improvement in physics-based modeling and highlights areas for ongoing research.

False alarm reduction in drilling process monitoring using virtual sample generation and qualitative trend analysis

Process monitoring is essential for ensuring the safety of geological drilling processes, but most existing monitoring systems suffer from false alarms. This study is motivated by the fact that many false alarms are generated from dynamic changes in signals under normal conditions. A new process monitoring method is proposed by analyzing the relationship between the input and output signals of a drilling normal behavior model, enabling a fault detection decision by checking their qualitative trends at the change point. The main novelties of this study are: (i) a data-driven normal behavior model describing the fault-free operating condition is proposed to output expected healthy virtual samples; (ii) a new alarm generation strategy is designed for reducing false alarms in drilling processes based on change point detection and qualitative trend analysis. Industrial case studies demonstrate the effectiveness and practicability of the method.

Spin-mediated Mott excitons

Motivated by recent experiments on Mott insulators, in both iridates and ultracold atoms, we theoretically study the effects of magnetic order on the Mott-Hubbard excitons. In particular, we focus on spin-mediated doublon-holon pairing in Hubbard materials. We use several complementary theoretical techniques: Mean-field theory to describe the spin degrees of freedom, the self-consistent Born approximation to characterize individual charge excitations across the Hubbard gap, and the Bethe-Salpeter equation to identify bound states of doublons and holons. The binding energy of the Mott exciton is found to increase with increasing the N\'eel order parameter, whereas the exciton mass decreases. We observe that these trends rely significantly on the retardation of the effective interaction, and require consideration of multiple effects from changing the magnetic order. Our results are consistent with the key qualitative trends observed in recent experiments on iridates. Moreover, the findings could have direct implications on ultracold atom Mott insulators where the Hubbard model is the exact description of the system and the microscopic degrees of freedom can be directly accessed.

Gas-phase metallicity break radii of star-forming galaxies in IllustrisTNG

ABSTRACT We present radial gas-phase metallicity profiles, gradients, and break radii at redshift z = 0–3 from the TNG50-1 star-forming galaxy population. These metallicity profiles are characterized by an emphasis on identifying the steep inner gradient and flat outer gradient. From this, the break radius, Rbreak, is defined as the region where the transition occurs. We observe the break radius having a positive trend with mass that weakens with redshift. When normalized by the stellar half-mass radius, the break radius has a weaker relation with both mass and redshift. To test if our results are dependent on the resolution or adopted physics of TNG50-1, the same analysis is performed in TNG50-2 and Illustris-1. We find general agreement between each of the simulations in their qualitative trends; however, the adopted physics between TNG and Illustris differ and therefore the breaks, normalized by galaxy size, deviate by a factor of ∼2. In order to understand where the break comes from, we define two relevant time-scales: an enrichment time-scale and a radial gas mixing time-scale. We find that Rbreak occurs where the gas mixing time-scale is ∼10 times as long as the enrichment time-scale in all three simulation runs, with some weak mass and redshift dependence. This implies that galactic discs can be thought of in two-parts: a star-forming inner disc with a steep gradient and a mixing-dominated outer disc with a flat gradient, with the break radius marking the region of transition between them.

Computing the Differences between Asn-X and Gln-X Deamidation and Their Impact on Pharmaceutical and Physiological Proteins: A Theoretical Investigation Using Model Dipeptides

Protein deamidation is a degradation mechanism that significantly impacts both pharmaceutical and physiological proteins. Deamidation impacts two amino acids, Asn and Gln, where the net neutral residues are converted into their acidic forms. While there are multiple similarities between the reaction mechanisms of the two residues, the impact of Gln deamidation has been noted to be most significant on physiological proteins while Asn deamidation has been linked to both pharmaceutical and physiological proteins. For this purpose, we sought to analyze the thermochemical and kinetic properties of the different reactions of Gln deamidation relative to Asn deamidation. In this study, we mapped the deamidation of Gln-X dipeptides into Glu-X dipeptides using density functional theory (DFT). Full network mapping facilitated the prediction of reaction selectivity between the two primary pathways, as well as between the two products of Gln-X deamidation as a function of solvent dielectric. To achieve this analysis, we studied a total of 77 dipeptide reactions per solvent dielectric (308 total reactions). Modeled at a neutral pH and using quantum chemical and statistical thermodynamic methods, we computed the following values: enthalpy of reaction (ΔHRXN), entropy (ΔSRXN), Gibbs free energy of reaction (ΔGRXN), activation energy (EA), and the Arrhenius preexponential factor (log(A)) for each dipeptide. Additionally, using chemical reaction principles, we generated a database of computed rate coefficients for all possible N-terminus Gln-X deamidation reactions at a neutral pH, predicted the most likely deamidation reaction mechanism for each dipeptide reaction, analyzed our results against our prior study on Asn-X deamidation, and matched our results against qualitative trends previously noted by experimental literature.

πσ*-Mediated Nonadiabatic Tunneling Dynamics of Thiophenols in S1: The Semiclassical Approaches.

The S-H bond tunneling predissociation dynamics of thiophenol and its ortho-substituted derivatives (2-fluorothiophenol, 2-methoxythiophenol, and 2-chlorothiphenol) in S1 (ππ*) where the H atom tunneling is mediated by the nearby S2 (πσ*) state (which is repulsive along the S-H bond extension coordinate) have been investigated in a state-specific way using the picosecond time-resolved pump-probe spectroscopy for the jet-cooled molecules. The effects of the specific vibrational mode excitations and the SH/SD substitutions on the S-H(D) bond rupture tunneling dynamics have been interrogated, giving deep insights into the multidimensional aspects of the S1/S2 conical intersection, which also shapes the underlying adiabatic tunneling potential energy surfaces (PESs). The semiclassical tunneling rate calculations based on the Wentzel-Kramers-Brillouin (WKB) approximation or Zhu-Nakamura (ZN) theory have been carried out based on the ab initio PESs calculated in the (one, two, or three) reduced dimensions to be compared with the experiment. Though the quantitative experimental results could not be reproduced satisfactorily by the present calculations, the qualitative trends among different molecules in terms of the behavior of the tunneling rate versus the (adiabatic) barrier height or the number of PES dimensions could be rationalized. Most interestingly, the H/D kinetic isotope effect observed in the tunneling rate could be much better explained by the ZN theory compared to the WKB approximation, indicating that the nonadiabatic coupling matrix elements should be invoked for understanding the tunneling dynamics taking place in the proximity of the conical intersection.

Hydration Free Energies of Polypeptides from Popular Implicit Solvent Models versus All-Atom Simulation Results Based on Molecular Quasichemical Theory.

Calculating the hydration free energy of a macromolecule in all-atom simulations has long remained a challenge, necessitating the use of models wherein the effect of the solvent is captured without explicit account of solvent degrees of freedom. This situation has changed with developments in the molecular quasi-chemical theory (QCT)─an approach that enables calculation of the hydration free energy of macromolecules within all-atom simulations at the same resolution as is possible for small molecular solutes. The theory also provides a rigorous and physically transparent framework to conceptualize and model interactions in molecular solutions and thus provides a convenient framework to investigate the assumptions in implicit solvent models. In this study, we compare the results using molecular QCT versus predictions from EEF1, ABSINTH, and GB/SA implicit solvent models for polyglycine and polyalanine solutes covering a range of chain lengths and conformations. The hydration free energies or the differences in hydration free energies between conformers obtained from the implicit solvent models do not agree with explicit solvent results, with the deviations being largest for the group additive EEF1 and ABSINTH models. GB/SA does better in capturing the qualitative trends seen in explicit solvent results. Analysis founded on QCT reveals the critical importance of the cooperativity of hydration that is inherent in the hydrophilic and hydrophobic contributions to hydration─physics that is not well captured in additive models but somewhat better accounted for by means of a dielectric in the GB/SA approach.

Nucleation of recrystallization in magnesium alloy grains of varied orientation and the impacts on texture evolution

Selection of appropriate thermomechanical processing parameters is crucial for control of the crystallographic texture and grain size distribution in wrought magnesium alloys, which in turn dictate their mechanical properties. In this work, the recrystallization behavior of binary Mg-Zn alloys are examined after warm rolling as a function of alloy content and heat treatment temperature. The Avrami exponent increased with increasing heat treatment temperature up to the MgZn solvus, while the strength of the recrystallization texture decreased. Neither the Avrami exponent nor the qualitative trends in texture evolution were sensitive to the Zn alloying content in the examined range. EBSD and transmission electron microscopy observations revealed that the changes in texture and recrystallization kinetics could be attributed to differences in the nucleation behavior of basal and off-basal orientations.

Importance of Nuclear Quantum Effects on Aqueous Electrolyte Transport under Confinement in Ti3C2 MXenes.

Protons display a high chemical activity and strongly affect the charge storage capability in confined interlayer spaces of two-dimensional (2D) materials. As such, an accurate representation of proton dynamics under confinement is important for understanding and predicting charge storage dynamics in these materials. While often ignored in atomistic-scale simulations, nuclear quantum effects (NQEs), e.g., tunneling, can be significant under confinement even at room temperature. Using the thermostatted ring polymer molecular dynamics implementation of path integral molecular dynamics (PIMD) in conjunction with the ReaxFF force field, density functional tight binding (DFTB), and NequIP neural network potential simulations, we investigate the role of NQEs on proton and water transport in bulk water and aqueous electrolytes under confinement in Ti3C2 MXenes. Although overall NQEs are relatively small, especially in bulk, we find that they can alter both quantitative values and qualitative trends on both proton transport and water self-diffusion under confinement relative to classical MD predictions. Therefore, our results suggest the need for NQEs to be considered to simulate aqueous systems under confinement for both qualitative and quantitative accuracy.

Numerical and experimental investigation of convective flow boiling in vertical annulus using CFD code: Effect of mass flow rate and wall heat fluxes

In this paper a numerical and experimental analysis of convective flow boiling in a vertical annular channel has been performed. As the best substitute for water, a refrigerant Trichlorofluoromethane CCl3F (R11) has been selected for the working fluid in the experiment to evaluate the capability of the Computational Fluid Dynamic (CFD) codes to predict the heat transfer rates, transitions points and the boiling flow regime. The experiments cover a wide range of mass fluxes (435–1443 kg/m2 s) and heat fluxes (1.81–11.5 W/cm2), which enabled to study the influence of different boundary conditions on the development of local boiling phenomena up to CHF occurrence. The contribution of each of the mechanisms for transfer of heat to the liquid – forced convection and quenching, as well as the energy transport associated with vapor generation has been quantified in terms of nucleation site densities, bubble departure, bubble detachment frequency, flow parameters like velocity, inlet subcooling and wall superheat. The qualitative and quantitative trends of the parameters studied experimentally are also supported by the analysis and observation of the various phenomena visualized. A sensitivity analysis of several modeling parameters on the radial distribution of flow quantities has highlighted the importance of correct description of the boiling model. Also, some measurements have been compared to the predictions by the three-dimensional two-fluid model of subcooled boiling flow carried out with the computer code. The computational method has been tested against experimental data. The comparison shows a good agreement between the predicted and experimental results.

Proton damage in (Y,Lu,Gd)3(Al,Ga)5O12:Ce mixed garnet scintillators.

Scintillators are vital components for nuclear instrumentation and its applications, including plasma diagnostics and imaging. As yields in controlled fusion experiments increase, the radiation tolerance of scintillator candidates for use in instrumentation is of particular importance. High radiation exposure can damage scintillating materials and alter the optical properties. The effects of radiation damage in Ce-doped mixed garnet ceramics over the compositional range (Y,Gd,Lu)3(Al,Ga)5O12 are investigated using optical techniques. The samples were exposed to 200keV protons to an accumulated fluence of 1016 protons per square centimeter, then characterized using diffuse reflectance spectroscopy (DRS). DRS with visible light can assess the radiation tolerance of opaque poly-crystalline samples, which can be easily sintered from powders and thus offer distinct advantages in characterization compared to single crystals. Qualitative trends in induced absorption are presented as a function of composition, and the ideal cerium dopant concentration for Y2LuAl5O12 is determined to be 0.60-0.75 mol. %.

Schmid factor crack propagation and tracking crystallographic texture markers of microstructural condition in direct energy deposition additive manufacturing of Ti-6Al-4V

Metallic additive manufacturing (AM) provides a customizable and tailorable manufacturing process for new engineering designs and technologies. The greatest challenge currently facing metallic AM is maintaining control of microstructural evolution during solidification and any solid state phase transformations during the build process. Ti-6Al-4V has been extensively surveyed in this regard, with the potential solid state and solidification microstructures explored at length. This work evaluates the applicability of previously determined crystallographic markers of microstructural condition observed in electron beam melting powder bed fusion (PBF-EB) builds of Ti-6Al-4V in a directed energy deposition (DED) build process. The aim of this effort is to elucidate whether or not these specific crystallographic textures are useful tools for indicating microstructural conditions in AM variants beyond PBF-EB. Parent β -Ti grain size was determined to be directly related to α -Ti textures in the DED build process, and the solid state microstructural condition could be inferred from the intensity of specific α -Ti orientations. Qualitative trends on the as-solidified β -Ti grain size were also determined to be related to the presence of a fiber texture, and proposed as a marker for as-solidified grain size in any cubic metal melted by AM. Analysis of the DED Ti-6Al-4V build also demonstrated a near complete fracture of the build volume, suspected to originate from accumulated thermal stresses in the solid state. Crack propagation was found to only appreciably occur in regions of slow cooling with large α + β colonies. Schmid factors for the basal and prismatic α -Ti systems explained the observed crack pathway, including slower bifurcation in colonies with lower Schmid factors of both slip systems. Colony morphologies and localized equiaxed β -Ti solidification were also found to originate from build pauses during production and uneven heating of the build edges during deposition. Tailoring of DED Ti-6Al-4V microstructures with the insight gained here is proposed, along with cautionary insight on preventing unplanned build pauses to maintain an informed and controlled thermal environment for microstructural control.

Forward-modeling of co-evolution of turbidity currents, sediment transport, and cyclic steps in the Rio Muni Basin

Previous quantitative studies of field-scale cyclic steps are mostly based on analysis of field data. Such studies have shed light on the erosion/deposition patterns over these morphological features as well as the magnitudes of the turbidity current parameters back estimated using the measured geometry data. However, it remains unclear to what extent such back estimated hydraulic features and erosion/deposition patterns can be numerically reproduced by process-based numerical models. Here, a two-dimensional layer-averaged fully coupled turbidity current model is applied to forward-model co-evolution of turbidity currents, sediment transport, and cyclic steps in the Rio Muni Basin off the West Africa margin, where nine cyclic steps featuring a transition from the upstream erosion to the downstream deposition were identified. Numerical case studies indicate that large and bankfull turbidity currents do not form the erosion-deposition transition because they are likely to fall into the high-speed regime that favors whole-scale erosion. In this regard, threshold values for the current velocity were derived to distinguish high/low-speed regimes of turbidity currents. It is shown that smaller turbidity currents, which do not follow the bankfull assumption, and, thus, fall into the low-speed turbidity current regime, may produce cyclic steps by current deceleration. While values of the derived physical parameters of the smaller turbidity current differ quantitatively from those of previous back estimated values, their qualitative variation trends are basically the same.

Kinetic Model for Galacto-Oligosaccharide Synthesis

A new micro-kinetic model is proposed for galacto-oligosaccharide (GOS) synthesis with β-galactosidase from Aspergillus oryzae. Several kinetic models with similar reaction mechanisms, i.e., steps and kinetic constants, have been investigated covering a range of initial lactose (20–40 wt %) and enzyme concentrations (0.5–2 mg/mL). The kinetic parameters were estimated simultaneously for all experimental results using a hybrid genetic algorithm. A detailed analysis of the effect of process parameters on the concentrations of lactose and GOS is performed. The proposed model has a very good quantitative fit of the experimental data, with an average error of 9.34%. More importantly, qualitative trends for the change in the concentration of lactose and GOS are predicted excellently, especially if one takes into account the variation of both concentrations of enzyme and lactose in a range wider than reported in the literature to date. Also, the analysis between the two comparative reactions of transglycosylation and lactose hydrolysis confirmed the positive effect of increasing lactose concentration on the production of GOS. On the other hand, a higher enzyme concentration resulted in a faster production of GOS but with more intensive decomposition at longer reaction times.