bluuebunny/crossref_metadata_2025 huggingface dataset:
formation of meta-stable sodium sulphate heptahydrate during drying as studied by NMR
Authors: Saidov Tamerlan , Pel Leo
Published: July 2024

Salt weathering is a major cause of deterioration of porous building materials. Of the salts responsible, especially sodium sulfate is seen as very damaging. However many questions arise concerning which sodium sulfate phase will crystallize out during salt weathering. In this study we focused on the crystallization during isothermal drying of a sample saturated with a sodium sulfate solution. As the material is drying moisture will leave and hence the salt concentration will rise until the maximum solubility is reached. From that point on crystals will be formed. Using NMR we have measured quasi simultaneously both the moisture and Na profiles during drying. These experiments have been performed at various temperatures and concentrations. In our NMR experiments we observe the formation of a metastable phase of sodium sulfate, the heptahydrate crystals.
In vivo imaging of signal decay due to diffusion in the internal field in human knee trabecular bone
Authors: Sigmund Eric , Regatte Ravinder , Schweitzer Mark , Cho Hyungjoon , Song Yi-Qiao
Published: July 2024

This study presents the first demonstration of the MR signal decay due to diffusion in the internal field (DDIF) for in vivo knee trabecular bone imaging. DDIF contrast was compared with high resolution FLASH, T1, and T2* mapping in healthy volunteers. DDIF maps showed spatial variation, superimposed on a T1 background, reflecting trabecular structure. DDIF and T2* maps showed correlated contrast near dense trabeculae, but their spatial textures differed, suggesting distinct structural sensitivities.
Microscopic wettability of carbonate rocks
Authors: Freiman Gabriel , Korb Jean-Pierre , Nicot Benjamin , Ligneul Patrice
Published: July 2024

Nuclear Magnetic Relaxation Dispersion (NMRD) is strongly sensitive to the microscopic wettability of oil and brine bearing carbonate rocks. Exploring a very large range of low frequency enables isolating the typical NMRD dispersion features, 1/T1Surf, associated to the different processes of molecular surface dynamics. This allows a separation of the surface and bulk microdynamics of oil and water even for a biphasic saturation of petroleum rocks. Several surface dynamical parameters were determined and related to the concept of microscopic wettability of oil and water in porous media.
numerical analysis of NMR pore-pore exchange measurements using micro X-ray computed tomography
Authors: Melean Y. , Washburn Kathryn E. , Callaghan P. T. , Arns Christoph H.
Published: July 2024

Pore-pore relaxation exchange experiments are a recent development and hold great promise to spectrally derive length scales and connectivity information relevant for transport in porous media. However, for large pores, NMR diffusion-relaxation techniques reach a limit because bulk relaxation becomes dominant. A combination of NMR and Xray-CT techniques could be beneficial and lead to better models for regions of unresolved porosity in CT images, increasing the accuracy of image based calculations of transport properties. In this study we carry out numerical NMR pore-pore exchange experiments on selected Xray-CT images of sandstones and carbonate rock, while at the same time tracking information about the geometry and topology of the pore space. We use pore partitioning techniques and geometric distance fields to relate T2-T2 relaxation exchange spectra to underlying structural quantities. It is shown that T2-T2 pore-pore exchange measurements at room temperatures for the samples considered likely reflect exchange between pores and throats or pores and roughness.
Innovation diffusion in time and space
Authors: Kandler Anne , Steele James
Published: July 2024

In this paper we consider the spread of modern technological innovations. We contrast social learning and threshold heterogeneity models of innovation diffusion, and show how the typical temporal evolution of the distribution of adopters may be consistent with either explanation. Noting the likelihood that each model contains some useful independent explanatory power, we introduce a combined model. We also consider a spatially-structured population in which the spread of an innovation by social influence is modelled as a reaction-diffusion system, and show that the typical spatiotemporal evolution of the distribution is also consistent with a heterogeneity explanation. Additional contextual information is required to estimate the relative importance of social learning and of economic inequalities in observed adoption lags.
Diffusion through porous media
Authors: Ruthven Douglas M.
Published: July 2024

This paper considers permeation through microporous or nanoporous inorganic membranes under the influence of an applied pressure gradient. In general membrane permeation may be considered as a diffusive process, driven by the gradient of chemical potential (which depends on both composition and pressure). The relative importance of these two factors varies greatly for different types of system. The general features of such processes are reviewed and the diffusional behavior of selected systems is examined (membrane permeation, osmosis, diffusion, zeolite membrane, DDR-3, SAPO-34).
Diffusion welding of nickel-based superalloys
Authors: Rezaei Hossein
Published: July 2024

Ni based superalloys can be welded by diffusion bonding. Temperature, diffusion coefficient, activation energy and Boltzmann constant influence the quality of diffusion bonding, so obtaining the best condition for welding is considered. Showing the suitable condition for diffusion welding of nickel-based superalloys is the aim of this paper.
Robust estimator framework in diffusion tensor imaging
Authors: Maximov Ivan I. , Grinberg Farida , Shah Nadim Jon
Published: July 2024

Diffusion of water molecules in the human brain tissue has strong similarities with diffusion in porous media. It is affected by different factors such as restrictions and compartmentalization, interaction with membrane walls, strong anisotropy imposed by cellular microstructure, etc. However, multiple artefacts abound in in vivo measurements either from subject motions, such as cardiac pulsation, bulk head motion, respiratory motion, and involuntary tics and tremor, or hardware related problems, such as table vibrations, etc. All these artefacts can substantially degrade the resulting images and render postprocessing diffusion analysis difficult or even impossible. In order to overcome these problems, we have developed a robust and efficient approach based on the least trimmed squares algorithm that works well with severely degraded datasets with low signal-to-noise ratio. This approach has been compared with other diffusion imaging post-processing algorithms using simulations and in vivo experiments. We demonstrate that the least trimmed squares algorithm can be easily adopted for multiple non-Gaussian diffusion models such as the biexponential model. The developed approach is shown to exhibit a high efficiency and accuracy and can, in principle, be exploited in other diffusion studies where artefact/outlier suppression is demanded.
Study of dispersion by NMR
Authors: Ferrari Maude , Mérel J.-P. , Leclerc Sébastien , Moyne Christian , Stemmelen Didier
Published: July 2024

Dispersion remains, today, a highly topical subject. Our group has been interested in characterizing this phenomenon by pulsed-field-gradient NMR technique. Direct measurement of the dispersion coefficient can be done with a Pulsed Gradient Spin Echo (PGSE) sequence by assuming that the asymptotic regime is reached. In unsteady state, the propagator formalism is used. To better understand these measurements, the NMR experiment is modeled using a stochastic simulation (random walks) and compared with experimental results. The comparison is made for the simple case of Poiseuille flow in a circular tube (Taylor-Aris dispersion).
Diffusion of light gases in 6FDA/BPDA-DAM Carbon Molecular Sieve membranes by Pulsed Field Gradient NMR
Authors: Mueller Robert , Kanungo Rohit , Kiyono-Shimobe Mayumi , Koros William J. , Vasenkov Sergey
Published: July 2024

In this paper, we demonstrate the potential of pulsed field gradient (PFG) NMR spectroscopy to reveal detailed knowledge of self-diffusion of light gases and light gas mixtures in carbon molecular sieve membranes on small length scales. PFG NMR is used to investigate intra-membrane diffusion of carbon dioxide and methane for a broad range of temperatures and mean square displacements in a carbon molecular sieve membrane derived from a 6FDA/BPDA-DAM polyimide film. Diffusion is investigated with single component sorbates as well as with a carbon dioxide / methane mixture. Results obtained from these studies are compared and discussed.
Magnetic Resonance Imaging of gas hydrate formation and conversion at sub-seafloor conditions
Authors: Kossel Elke , Deusner Christian , Bigalke Nikolaus , Haeckel Matthias
Published: July 2024

The production of natural gas from sub-seafloor gas hydrates is one possible strategy to meet the world’s growing demand for energy. On the other hand, climate warming scenarios call for the substitution of fossil energy resources by sustainable energy concepts. Burning natural gas from gas hydrates could be emission neutral if it was combined with a safe storage of the emitted CO2. Laboratory experiments, that address corresponding strategies, need to be performed under high pressures and low temperatures to meet the thermodynamic conditions of the sub-seafloor environment. In this paper, we present a high-pressure flow-through sample cell that is suitable for nuclear magnetic resonance (NMR) experiments at realistic marine environmental conditions, i.e. pressures up to 15 MPa and temperatures from 5 to 20°C, and we demonstrate its suitability in applied gas hydrate research.
Single-file diffusion far from equilibrium
Authors: Schütz Gunter M.
Published: July 2024

The stationary states of driven diffusive single-file systems, connected to boundary reservoirs with fixed particle density are shown to be selected by an extremal principle for the macroscopic current. Given the current one obtains the exact first- and secondorder non-equilibrium phase transition lines for the bulk density as a function of the boundary densities. The basic dynamical mechanism behind the extremal principle is an intriguing generic interplay between the motion of shocks and localized perturbations. Two-component driven systems exhibit unexpected and fascinating critical phenomena.
Correlating self- and transport diffusion in the Knudsen regime
Authors: Bunde Armin , Kärger Jörg , Russ Stefanie , Zschiegner Stephan
Published: July 2024

Comparing the rates of molecular diffusion in porous materials under different regimes of measurement may provide valuable information about the underlying mechanisms. After quite generally explaining the benefit of such a procedure, we refer to a case which in the last few years has raised controversial discussion within the community, viz. the comparison of diffusion phenomena in pores of varying roughness in the so-called Knudsen regime. Knudsen diffusion represents the limiting case of molecular diffusion in pores, where mutual encounters of the molecules within the free pore space may be neglected and the time of flight between subsequent collisions with the pore walls significantly exceeds the interaction time between the pore wall and the molecules. In our studies, the coefficients of self- and transport diffusion are found to be in satisfactory agreement, which contradicts previous literature data. A number of effects which might becloud this relationship are discussed.
How two pairs of gradient pulses give access to new information about molecular dynamics
Authors: Callaghan Paul T.
Published: July 2024

Pulsed Gradient Nuclear Magnetic Resonance provides direct insight regarding the translational motion of spin-bearing molecules. These methods gain a second dimension when the simple gradient pulse pair is enhanced by a second pair. Where the motion encoding of the two pairs is opposite, flow effects are removed from the echo attenuation, making it possible to measure diffusion in the presence of shear flow, or to measure the stochastic part of dispersive flow, and in particular the velocity auto-correlation function. Where the gradient pulse pairs are stepped in independent dimensions, two-dimensional experiments become possible. One class (Fourier-Fourier) is the Velocity Exchange (VEXSY) experiment in which flow velocities may be correlated at different times. Another class (inverse Laplace-inverse Laplace) is the diffusion correlation (DDCOSY) or diffusion exchange (DEXSY) experiment. This approach has proven of particular value in ascertaining local anisotropies in globally isotropic systems, as well as in the model-free measurement of exchange effects.
Accessible catalyst pore volumes, for water and organic liquids, as probed by NMR cryoporometry
Authors: Webber John Beausire Wyatt
Published: July 2024

Chemical reaction speed is frequently enhanced at a surface, particularly when materials like platinum are present. It is well known that porous materials such as sol-gel silicas, controlled pore glasses, templated porous materials such as SBA-15, MCM-41, MCM-48, and zeolites, offer large surface areas. This in turn makes them ideal for catalysing chemical reactions. Thus an important use for porous materials is as a substrate and media to promote chemical reactions. However small pores are not always easily accessed by some of the organic liquids in which these catalytic reactions ideally take place. Cryoporometric techniques offer the possibility of directly probing the fraction of a pore that is actually accessible to a probe liquid. This fractional volume has significant impact on the catalytic efficacy of a particular solvent that is used to promote a reaction in the pores. Pore size, pore geometry, pore throat, pore surface material (hydrophilic/hydrophobic) and choice of probe liquid all influence the accessible fraction. By performing an NMR cryoporometric measurement using a particular liquid of interest, it is possible to directly access this information, which is of prime importance for catalysis, and financially very significant on an industrial scale. Results are reported here for a set of liquids, some simple alkanes (dodecane, tetradecane and hexadecane) plus water and cyclohexane, accessing pores in sol-gel silicas of nominal pore diameters 60Å, 100Å, 200Å, 500 Å. The key conclusions were that for the alkanes, the dimension of chain length was not relevantto the filling fraction, however for the cyclohexane a molecular diameter of 3.8 Å fitted the data well.
DNA under confinement and the use of DNA as confinement
Authors: Brutzer Hergen , Sperling Evgeni , Günther Katrin , Dikic Jasmina , Schwarz Friedrich , Klaue Daniel , Cichos Frank , Mertig Michael , Seidel Ralf
Published: July 2024

In living systems DNA is subjected to considerable confinement but the molecule acts itself also as a confinement mechanism for cellular structures. Here we present investigations that study DNA under the confinement of supercoiling and within nanofluidic channels. Furthermore, we use DNA to confine the motion of microscopic and nanoscopic objects. In particular, we show how the motion dynamics of DNA-attached magnetic particles under external tension is affected and how DNA can confine the diffusion of enzymes to one dimension to follow the DNA contour.
Structural Characterisation of Hierarchically Porous Silica
Authors: Hwang Seungtaik , Valiullin Rustem , Haase Jürgen , Smarsly Bernd M. , Bunde Armin , Kärger Jörg
Published: July 2024

A systematic NMR cryo-porometry and -diffusometry study using nitrobenzene as a probe liquid is carried out in order to characterise pore structures of hierarchically-organised porous silica monolith possessing mesopores along with a 3D bicontinuous macropore network. The result obtained from NMR cryoporometry shows the presence of a relatively wide mesopore size distribution of 10-35 nm. Furthermore, NMR cryodiffusometry indicates that whilst the mesopores are highly tortuous (Tmeso ≈6), they have little influence on the overall tortuosity of the material (Tmacro ≈1.5), which is largely dominated by the macropores (Toverall ≈1.7).
Uptake of the herbicide 2,4-dichlorophenoxyacetate (2,4-D) by Delftia acidovorans MC1 - complex kinetic characteristics in dependence of pH and growth substrate
Authors: Müller Roland H. , Hoffmann Doreen
Published: July 2024

The uptake of the herbicide 2,4-dichlorophenoxyacetate (2,4-D) by the bacterial strain Delftia acidovorans MC1 was studied using 14C-labeled compound. Implication of active transport was suggested due to the effect of carbonylcyanide m-chlorophenylhydrazone (CCCP) as an uncoupler of the proton motive force, the presence of which reduced the uptake rate by up to 90%. Kinetic characteristics revealed a complex pattern that was strongly affected by the external pH. With 2,4-D-grown cells, the uptake characteristics followed a hyperbolic shape at pH 6.8 showing an intermediary plateau at ca. 20-100 μM 2,4-D. In contrast, the kinetics at pH 7.5 and 8.5 revealed a sigmoidal pattern. The maximum rate was obtained at around 400 μM 2,4-D, and amounted to 15-20 nmol/min*mg protein. Higher substrate concentrations led to inhibition. With cells grown on (RS)-2-(2,4-dichlorophenoxy)propionate [(RS)-2,4-DP], the uptake rate increased to about 65 nmol/min*mg protein which hints at substrate-dependent induction of specific carrier(s). With 2,4-D-grown cells, such a high rate was obtained only after cloning and expression of the tfdK gene, which encodes a specific transporter for 2,4-D. The uptake pattern of 2,4-D changed with mutant strains of MC1 that were phenotypically deficient of cleavage activity to ether bond in phenoxyalkanoate herbicides. Apparently, genes coding for proteins in uptake function were in addition deleted. With strains that lacked (R)-2,4-DP cleavage, the plateau disappeared and the kinetics followed a more continuous pattern. Strains that lacked (S)-2,4-DP cleavage showed faint 2,4-D uptake at all. The present picture hints at three proteins that are involved in 2,4-D uptake by active transport. With degradation-negative mutants of strain MC1, the influx of 2,4-D proceeded at a low rate. It was linearly dependent on the 2,4-D concentration correspond-ding to a micro-molar rate constant of 1.08*10-5 min-1 mg protein-1. The latter hints at 2,4-D influx into the cell by diffusion via cytoplasmic membrane at a low rate.
Grain size influence on the release of radioactive isotopes out of target materials made of powder
Authors: Kuchi V. , Jardin P.
Published: July 2024

Radioactive ion beam production by Isotope Separator On Line method (ISOL) has motivated the construction of several nuclear facilities over the world. The method consists in impinging solid target material with beams of stable nucleus. Radioactive nuclei produced during the collision are stopped in the target material and must diffuse out of it as fast as possible to transform them into ions before their radioactive decay. The release time must thus be as short as possible to avoid their losses. The release of the nuclei depends on several parameters, which are related to the chemistry of the atoms in the target matrix, to the geometry and micro-structure of the target, and to its temperature. In the case of targets made of grains, we assumed that an optimum grain size of the grains existed. To make possible its easy determination, we aimed to calculate it analytically. Thus we have built a description of the propagation of the atoms in the target material, while conserving the different physico-chemical parameters and avoiding the use of adjustable parameters. The description of the propagation process will be presented as well as the assumptions. Finally, the optimum grain size will be given for the radioactive Ar atoms out of graphite.
On the Carbon Kinetics in Martensite, relevance to Nanosegregation at Dislocations and Grain Boundaries
Authors: Nechaev Yury S.
Published: July 2024

This short communication is devoted to the room temperature processes of diffusion and redistribution of dissolved carbon atoms in martensite to the nanosegregation regions at dislocations and grain boundaries. It is related to the DF7 contribution of M. Lavrskyi et al. on the carbon kinetics in martensite [1] and to the DF7 contribution of Yu. Nechaev on the compound-like nanosegregation at dislocations and grain boundaries in metallic materials.
Advancements in Magnetic Resonance in Porous Media
Authors: Bowers Clifford R. , Vasenkov Sergey
Published: July 2024

This is a brief summary of the Fourteenth International Bologna Conference on Magnetic Resonance in Porous Media (MRPM14).
Determining the Pore Size Distribution in Synthetic and Building Materials Using 1D NMR
Authors: Nagel Sarah Mandy , Strangfeld Christoph , Kruschwitz Sabine
Published: July 2024

NMR is gaining increasing interest in civil engineering for applications regarding microstructure characterization as e.g., to determine pore sizes or to monitor moisture transport in porous materials. This study reveals the capability of NMR as a tool for pore size characterization. Therefore, we measured floor screed and synthetic materials at partial and full saturation. For most examined materials, the pore size distribution was successfully determined using either a reference or a calibration method. Since diffusion effects were observed for some samples in single-sided NMR measurements, further tests employing an NMR core analyzer were carried out in a homogeneous magnetic field. The finally obtained surface relaxivity of floor screed (50 μm/s) resulted to be much higher than suggested by literature.
NB3Sn Targets Synthesis via Liquid Tin Diffusion for Thin Films Depositions
Authors: Zanierato Matteo , Azzolini Oscar , Cavazzani Jonathan , Chyhyrynets Eduard , Diaz Vanessa Garcia , Glisenti Antonella , Keppel Giorgio , Ragazzo Nico , Stivanello Fabrizio , Pira Cristian
Published: July 2024

The deposition of superconducting Nb3Sn on copper accelerating cavities is interesting for the higher thermal conductivity of copper compared to common Nb substrates. The better heat exchange would allow the use of cryocoolers reducing cryogenic costs and the risk of thermal quench [1]. The magnetron sputtering technology allows the deposition of Nb3Sn on substrates different than Nb, however the coating of substrates with complex geometry (such as elliptical cavities) may require target with non-planar shape, which are difficult to realize with classic powder sintering techniques. In this work, the possibility of using the Liquid Tin Diffusion (LTD) technique to produce sputtering targets is explored. The LTD technique is a wire fabrication technology, already developed in the past at LNL for superconducting radio frequency (SRF) applications [2], that allows the deposition of very thick and uniform coating on Nb substrates even with complex geometries [3]. Improvements in LTD process, proof of concept of a single use LTD target production, and characterization of the Nb3Sn film coated by DC magnetron sputtering with these innovative targets are reported in this work.
Simulation of structure of special tilt boundary and grainboundary self-diffusion in Ti
Authors: Popov Vladimir , Urazaliev Mihail , Stupak Maksim
Published: July 2024

Symmetric tilt boundary [2 110] (01 12) in HCP titanium has been investigated by computer simulation methods using the embedded atom potential. The structure and energies of the considered boundary and the energies of formation of vacancies in it have been calculated by the method of molecular-static simulation. The stability of the boundary at elevated temperatures has been investigated by the molecular dynamics method, and the coefficients of grain-boundary diffusion have been calculated.
Pseudopotential theory for the explanation of energetics of self-diffusion by a vacancy mechanism
Authors: Ghorai Amitava
Published: July 2024

Harrison’s pseudopotential approach of the derivation of activation energy for self-diffusion in metallic solids is explained here from the energy difference between pure lattice and otherwise activated lattice in relaxed conditions. This difference depends on the structure factor of the lattice and modifications in the lattice wave numbers. Separate expressions for monovacancy formation energy and monovacancy migration energy with relaxation energy of surrounding nearest neighbours are also calculated.
lattice Monte Carlo method for solving phenomenological mass and
heat transport problems
Authors: Belova Irina V. , Murch Graeme E. , Fiedler Thomas , Öchsner Andreas
Published: July 2024

In this review paper, we introduce the recently developed Lattice Monte Carlo method for addressing and solving phenomenologically-based mass and heat transport problems especially for composite and porous materials. We describe in detail the application of this method to calculate effective mass diffusivities and to determine concentration profiles. Next, we describe in detail the application of this method to the calculation of effective thermal conductivities/thermal diffusivities and the determination of temperature profiles. Where possible, results of the method are compared with exact results or those from application of the Finite Element method. Excellent agreement is demonstrated.
27 Al NMR/MRI Studies of the Transport of Granular Al 2 O 3
Authors: Koptyug Igor V. , Lysova Anna A. , Khomichev Alexey V. , Sagdeev Renad Z.
Published: July 2024

The NMR/MRI techniques are applicable to the studies of motion of granular solids, providing information on the velocities, effective diffusivities and correlation times of the moving particles. The studies of transport of granular solids reported to-date are based on the detection of the 1H NMR signal of the liquid phase of liquid-containing solid materials. Yet, the solid phase of many granular solids contains magnetic nuclei, providing in principle an opportunity to study motion of such solids by directly detecting the NMR signal of the solid phase. In this paper, we demonstrate that this can be performed with the use of conventional echo pulse sequences in combination with the conventional motion encoding schemes. The detection of the 27Al NMR signal of the Al2O3 powder was used to obtain velocity maps of the powder packed in a spinning cylinder, and to measure the velocity distribution (average propagator) for the gravity driven transport of the same powder in a vertical pipe.
Vapor contribution to the time dependence of the effective diffusion
coefficient in partially filled porous glasses
Authors: Farrher Germán , Ardelean Ioan , Kimmich Rainer
Published: July 2024

NMR microscopy of silica glasses with micrometer pores (Vitrapor#5) partially filled with water reveal heterogeneous distributions of the liquid on a length scale much longer than the pore dimension. This heterogeneity, which is not observed in MRI of saturated samples, is attributed to the spatial variation of the granular microstructure. As a consequence of the inhomogeneous filling degree, the effective transverse relaxation time varies, which in turn leads to NMR imaging contrasts. Since the spatial distribution of the transverse relaxation time prevents reliable measurements with the standard pulsed gradient stimulated echo technique (PGStE), a combination of the fringe field stimulated echo method (FFStE) on the one hand and the magnetization grid rotating frame imaging technique (MAGROFI) on the other was employed in our investigations. Using this combination four decades of the diffusion time from 100 μs to 1 s could be probed. The comparison of the experimental data with Monte Carlo simulations on a model structure has shown that the vapor phase contribution to the effective diffusivity is particularly efficient on a diffusion time scale corresponding to root mean squared displacements of the order of pores dimension.
Interference microscopy highlights properties and peculiarities of
SAPO STA-7 crystals
Authors: Tzoulaki Despina , Castro Maria J. , Kärger Jörg , Wright Paul Anthony
Published: July 2024

In the framework of this study a new generation of SAPO STA-7 crystals has been investigated with the help of Interference Microscopy. The ability of the abovementioned technique to record intracrystalline concentration profiles during uptake/release of guest molecules revealed oddities of the system under study. In other words, these crystals have the tendency to break in the middle, enhancing in this way diffusion. On the other hand, molecules have to confront high surface barriers when they try to diffuse through the other sides of the crystal, where it is not broken.
What might aquinas have said?
Authors: Kuchel Philip W. , Sahade Marcel V.
Published: July 2024

We present a comparison of two forms of analysis applied to a simple experiment in electrodynamics. One uses contemporary physics and the other metaphysics as espoused by the 13th century scholar Thomas Aquinas. The aim is to illustrate an example of scientific abstraction and prediction of experimental outcomes, and the pitfalls of applying simple intuition.
Effects of polydispersity on PGSE NMR coherence features
Authors: Yadav Nirbhay N. , Price William S.
Published: July 2024

Real systems always contain some degree of polydispersity and yet the effects of this real and very important problem have not been studied in great detail in NMR diffusion experiments. The effects of polydispersity become even less clear when we are outside the short gradient pulse (SGP) limit (which we generally are). Here we investigate the effects of polydispersity, in the form of a Gaussian distribution of characteristic distances, on the coherence features of PGSE NMR experiments of a model system. Characteristic pore sizes were determined from the coherence features and compared to characteristic distances determined from Fourier transforms of the second derivative.
Size dependence of solute diffusivity and Stokes-Einstein relationship: effect of van der Waals interaction
Authors: Sharma Manju , Yashonath Subramanian
Published: July 2024

Size dependence of solute diffusivity has been investigated using molecular dynamics simulations for a range of solute radii in a binary mixture consisting of solute and solvent species. We demonstrate that the Stokes-Einstein relationship between self diffusivity and solute radius breaks down over a range of solute-solvent size ratios. This is a result of the previously known Levitation Effect. Three distinct regimes can be seen depending on the solute-solvent size ratio. Several properties have been computed to understand the nature of solute motion in the three regimes.
Diffusion and defect reactions in isotopically controlled semiconductors
Authors: Bracht Hartmut
Published: July 2024

Point defects in semiconductors play a decisive role for the functionality of semiconductors. A detailed, quantitative understanding of diffusion and defect reactions of dopants is required for advanced modelling of modern nanometer size electronic devices. With isotope heterostructures which consist of epitaxial layers of isotopically pure and deliberately mixed stable isotopes, we have studied the simultaneous self- and dopant diffusion in several major semiconductors such as silicon and germanium. Detailed analysis of the simultaneous diffusion of self- and dopant atoms in Si and Ge yields information about the ionization levels of native defects and about dopant-defect interactions in Si and Ge. The results of these diffusion studies are highlighted in this work.
Mass transfer in one-dimensional nanoporous crystals with different surface permeabilities
Authors: Heinke Lars , Kärger Jörg
Published: July 2024

The use of optical techniques, such as interference microscopy and IR micro-imaging, has enabled the direct observation of transient concentration profiles. In a one-dimensional crystal, surface permeabilities on opposing crystal faces are usually equal, so that mass transfer occurs symmetrically and the fluxes through both crystal faces are identical. If the surface permeabilities on opposing crystal faces are different from each other, mass transfer is not symmetrical anymore. We are going to show that the fraction of molecular uptake (or release) through a given host face is inversely proportional to the time constant of uptake/release via this crystal face. This finding permits a straightforward estimate of the influence of asymmetry on overall uptake.
Quantitative study of near equilibrium in dissociative mechanism of nickel in silicon
Authors: Yoshida Masayuki , Kitagawa Hajime , Morooka Masami , Tanaka Shuji
Published: July 2024

The dissociative mechanism of nickel in silicon has been studied experimentally, assuming the near equilibrium represented by CiCV / Cs = Ci eq C eq / Cs eq , where subscripts i, V, and s represent interstitial nickel atoms, vacancies, and substitutional nickel atoms, respectively, superscript eq represents the thermal equilibrium, and CA is the concentration of component A. However, the assumption of the near equilibrium has not yet been verified experimentally, because it is difficult to measure CV in silicon. In the present work, the simultaneous diffusion equations of the dissociative mechanism of nickel in silicon are solved numerically by double-precision FORTRAN without assuming the near equilibrium under the condition of in-diffusion of nickel into a silicon specimen, and the establishment of the near equilibrium is verified. It is also clarified that the near equilibrium is a transitional process which continues until the thermal equilibrium is reached. After the near equilibrium is reached, the very small difference of two nearly equal terms is an important factor in solving the diffusion equations. In other words, high accuracy is necessary to solve the diffusion equations. Concerning this, it is verified that the accuracy of double-precision FORTRAN is sufficiently high to solve the diffusion equations in the present work.
Methods for droplet size distribution determination of water-inoil emulsions using low-field NMR
Authors: Opedal Nils van der Tuuk , Sørland Geir , Sjöblom Johan
Published: July 2024

A method using Pulsed Field Gradient Nuclear Magnetic Resonance PFG-NMR for water-incrude oil emulsion droplet size determination has been optimized and compared with optical microscope for validation. The method applies a combination of Pulsed-Field Gradient (PFG) NMR, Stimulated Echo (STE), and Carr-Purcell-Meimboom-Gill (CPMG) sequences for measuring diffusion, resolving oil and water signal and for measuring the attenuation due to a distribution in T2 values. This returns the droplet size distributions of water-in-oil emulsions within a minute. No prior assumption is made on the shape of the droplet size distribution, which enables the method to resolve for instance bimodal distributions. To validate this method, three different crude oils were used in the experiment. The emulsions prepared had water cuts from 10 to 40 %. The correlation between PFG-NMR and optical microscopy was good for the emulsions. Any potential discrepancies between the two techniques are discussed, so are the limitations and advantages of the methods.
High density of Tridacna crocea in Rita Island, Puerto Princesa City, Palawan, Philippines
Authors: Daño Jemima , Villanueva Elmer , Dolorosa Roger
Published: July 2024

In spite of being a protected species in the Philippines, the Tridacna crocea or crocus clam, the smallest among eight known giant clam species in the country, is getting rare in most reef areas of Palawan. However, a high density of this species has recently been noted in Rita Island, Ulugan Bay. A total of 44 photos with known dimensions having a total area of 13.26 m2 suitable habitats with clams were analyzed for size structure and density of T. crocea. In total, 215 T. crocea were noted with 84.91 (±25.6) mm average shell length (±sd). The average density (±sd) was 16.22 (±15.75) individual (ind)∙m-2 but the clams had occurred up to 17 individuals in 0.28 m2 or 59.91 ind∙m-2. This high density of T. crocea could be due to suitable environment and the absence of exploitation within the vicinity of the island resort. The importance of other resorts in biodiversity conservation may be investigated.
Problem-based Learning (PBL) Using Resource Mining as a Teaching Approach: An Action Research
Authors: Diquito Tomas Jr , Franco Aia Sept , Caballes Maria Ericka
Published: July 2024

Problem-Based Learning (PBL) is a teaching approach wherein learners are immersed in different issues to create real-life solutions. This approach is widely used to increase learners’ academic performance and promote positive behavioral change. Following the positive impacts of this approach, this study was conducted to uncover the possibility of merging PBL with secondary resources (articles, videos, recorded lectures) to create an innovative teaching approach responsive to the call for ICT integration in 21st-century education in teaching scientific concepts. A quasi-experimental research design was used in this study with a total of 240 Grade 7 participants (six sections). The selection of this target group is based on the PISA 2022 result wherein the Philippines have attained a very low performance in the scientific literacy component. Following this, a pretest was administered to each volunteered participant, and groupings were assigned based on the mean score of their result (control and experimental). Analysis shows no statistically significant difference in the targeted group’s pre-test performance, confirming that all groups have the same knowledge on the topic (atmospheric phenomena). The developed approach was implemented in the experimental group, and the control group was immersed in the traditional way of teaching. Data shows that the overall post-test performance of the experimental group is fairly satisfactory (%=79.73), while the control group’s performance did not meet the expectation (%=60.13). Analysis further revealed a statistically significant difference between the experimental and control groups. Moreover, when analyzed by Hake’s gain method, the experimental group achieved a medium gain performance while the control have achieved a low gain performance. The findings of this study imply that merging PBL with secondary resources can increase learners’ performance on atmospheric phenomena topics. Thus, this study suggests to use PBL with secondary resources in teaching environmental-related concepts to increase learners’ knowledge and awareness.
Collaboration of multi-stakeholder in integrated aid model for creative MSMEs in the tourism sector
Authors: Supriyanto Eko Eddya , Suparto Diryo , Rachmawati Meida , Saputra Jumadil
Published: July 2024

The goal of the study is to develop an integrated support model for small and medium-sized tourist firms that involves multi-stakeholder engagement. Specifically, this research identifies the mentoring model needed by SMEs in the tourism sector in Guci Hot Spring Tourism and Tegal Regency and navigates mentoring strategies that suit their needs by including multi-stakeholders. This research uses a qualitative approach with a case study of SMEs in the tourist area of Guci Hot Springs, Tegal Regency. Focus groups and in-depth interviews with SMEs in the tourist industry were employed for the purpose of gathering data. We analyzed 20 informants representing the SME sector in Guci Hot Springs consisting of fashion, culinary, and craft SMEs. Based on the qualitative data analysis carried out, the results state that the integrated assistance model covers substantive points such as marketing development, business permits and SME business entities, social media and information technology, and financial management. For more effective assistance, stakeholder involvement is very necessary. This study shows that stakeholders need their role and capacity to coordinate knowledge, management, and entrepreneurial spirit among SMEs in the tourism sector. As a result, this study's findings advance knowledge of how SMEs in the tourist industry may engage many stakeholders by using an integrated mentoring strategy.
Perspektif Mahasiswa tentang Rasa Puas (Santuá¹­á¹­hi) terhadap Pacar: Studi Kasus Mahasiswa STABN Sriwijaya Semester VIII Tahun Akademik 2022/2023
Authors: Angel Metta Cris , Muawanah Muawanah , Nyoto Nyoto
Published: July 2024

Humans are social beings who cannot live alone and cannot be separatedÂ  from the influence of other humans because humans need and influence oneÂ  another. One of the relationships that are owned is a relationship of love orÂ  courtship. Dating raises several problems, such as at STABN SriwijayaÂ  Tangerang Banten, it was found several cases of students, especially in the VIIIÂ  semester of the 2022/2023 Academic Year, who felt dissatisfied in being in aÂ  relationship, so they changed girlfriends, but there were also students who hadÂ  been in relationships for a long time. The purpose of this research is to describeÂ  students' perspectives about satisfaction (santuá¹­á¹­hi) to partner for students ofÂ  STABN Sriwijaya semester VIII for the 2022/2023 Academic Year.Â This study uses a qualitative approach with a case study model. TheÂ  informants in this study are students of STABN Sriwijaya semester VIII for theÂ  2022/2023 academic year who are Buddhists. Data collection techniques used,Â  namely observation, interviews, and documentation. Data were analyzed using theÂ  Miles, Huberman, and Saldana models. The data validity technique was carriedÂ  out by testing credibility, transferability, dependability, and confirmability.Â The results of this study concluded (1) Student perspectives about santuá¹­á¹­hiÂ  to girlfriends by STABN Sriwijaya students in semester VIII of the 2022/2023Â  academic year consisting of goals, knowing about santuá¹­á¹­hi, meaning, andÂ  importance. The goals of having a romantic relationship include: looking cool,Â  motivation to study or study, desire, marriage, encouragement, filling inÂ  deficiencies, and finding partners who share the same beliefs. Then students knowÂ  or not about santuá¹­á¹­hi data obtained include: satisfied with what is owned and doÂ  not know. Students' understanding of santuá¹­á¹­hi is the special person we choose,Â  not feeling lonely, as a home, not there, learning together, encouragement for life,Â  a place to tell stories of complaints, life partners, family, and motivation. ThenÂ  according to students feeling satisfied or santuá¹­á¹­hi it is important to have; (2)Â  Student constraints in expressing satisfaction or santuá¹­á¹­hi to boyfriend consists ofÂ  personal character, communication problems, not giving a sense of comfort,Â  changes in the nature of the partner, people talk, differences in thoughts, andÂ  stubbornness; (3) The way students express satisfaction or santuá¹­á¹­hi to partnersÂ  include: giving gifts, appreciating partners, paying attention, making partnersÂ  happy, concrete actions, improving oneself, asking for blessings, and conveyingÂ  them directly.Â Keywords: Perspective, Student, Santuá¹­á¹­hi
Peran pandita Magabudhi dalam implementasi moderasi beragama di Kota Tangerang Selatan
Authors: Houw Liong , Aman Anwar , Subekti Puja
Published: July 2024

Moderasi beragama akhir-akhir ini sangat penting dilakukan mengingat kemajemukan yang ada di Indonesia dalam hal suku, bangsa, budaya, agama, dan antar golongan masyarakat yang plural dan multikultur. Masyarakat Indonesia yang agamis, meskipun Indonesia bukan negara agama, dapat kita saksikan dalam aktivitasnya sehari-hari yang tidak lepas dari nilai-nilai agama. Keberadaan agama sangat vital di Indonesia sehingga sudah menjadi pedoman dalam kehidupan berbangsa dan bernegara. Perbedaan pemahaman dan penafsiran dalam beragama berimplikasi pada cara beragama yang berlebihan dan memunculkan sikap konservatif di satu sisi, dan liberal pada sisi lainnya. Menanggapi hal itu, Menteri Agama menuangkan Rencana Strategis Enam Misi Kementerian Agama RI ke dalam Peraturan Menteri Agama (PMA) Nomor 18 Tahun 2020.Tujuan penelitian ini adalah untuk mengetahui sejauh mana peran pandita MAGABUDHI dalam implementasi moderasi beragama di Kota Tangerang Selatan menyikapi PMA Nomor 18 Tahun 2020. Untuk mencapai tujuan penelitian tersebut, peneliti menggunakan metode penelitian kualitatif deskriptif dengan teknik observasi, wawancara, dan dokumentasi.Berdasarkan ajaran Buddha dalam Brahmavihara yang menjunjung tinggi sikap keragaman di dalam masyarakat, terutama masyarakat Buddhis. Hasil penelitian ini menunjukkan bahwa semua pandita MAGABUDHI menyikapi perlu adanya toleransi, saling menghormati dan saling menghargai sesama intra maupun antar umat beragama. Selain itu, perlu juga dikembangkan upaya-upaya mencari persamaan dalam kerukunan intra umat beragama, maupun kerukunan antar umat beragama, serta menjaga keutuhan Negara Kesatuan Republik Indonesia.Berdasarkan hasil penelitian tersebut peneliti menyimpulkan pandita MAGABUDHI mengimplementasikannya melalui cara-cara mengembangkan kepedulian kepada sesama dengan sikap moral yang dilandasi dengan welas asih dan cinta kasih di tengah-tengah suasana pandemi Covid-19 masih berlangsung, baik kepada umat Buddha, maupun masyarakat luas dimana umat Buddha membaur dalam aktivitas sehari-hariAkhirnya peneliti menyarankan agar PC MAGABUDHI Kota Tangerang Selatan perlu meningkatkan pengetahuan dan kemampuan para anggotanya dengan cara memberikan pembekalan berupa pendidikan dan pelatihan yang lebih intensif. Pendidikan dan pelatihan dapat meningkatkan kompetensi para pandita MAGABUDHI. Melalui pendidikan dan pelatihan juga bisa menjadi standar yang menyetarakan kompetensi para anggotanya.
Analisis Teori Belajar Kognitif dalam Motivasi Belajar Siswa Sekolah Minggu Buddha Chotipanno
Authors: Saccaka Agga , Endi Endi , Alim Inung Kurnia
Published: July 2024

Rata-rata usia anak sekolah minggu Buddha adalah masa-masa disaat mereka sering kali lebih banyak menghabiskan waktunya untuk bermain, dimana peneliti ketahui banyaknya siswa yang enggan untuk mengikuti Sekolah Minggu Buddha disebabkan oleh hal tersebut. Penelitian ini betujuan untuk membantu siswa lebih termotivasi mengikuti sekolah minggu buddha melalui teori belajar kognitif sebagai implementasi proses belajar mengajar siswa di Sekolah Minggu Buddha. Adapun metodelogi yang dipergunakan dalam melakukan kajian ini adalah menggunakan metode kualitatif. Teknik yang digunakan yaitu pengumpulan data dengan melakukan observasi, wawancara, dan dokumentasi. Analisis data yang digunakan peneliti adalah model interaktif Miles dan Huberman, yaitu pengumpulan data, reduksi data, penyajian data, dan penarikan kesimpulan. Hasil utama dari kajian ini menunjukan bahwa siswa Sekolah Minggu Buddha Chotipanno memilki tingkat motivasi yang cukup untuk mengikuti kegiatan Sekolah Minggu Buddha. Terdapat beberapa pemanasan sebelum, pertengahan, maupun di akhir kegiatan berupa ice breaking. Hal ini dilakukan dengan tujuan agar siswa sekolah minggu tidak merasa jenuh kembali akan memulai kegiatan. Dimana dari hasil tersebut dapat di tarik kesimpulan bahwa motivasi belajar di Sekolah Minggu Buddha Chotipanno cukup baik tetapi dalam perkembangan kognitif atau pengetahuannya masih harus diperdalam kembali. Mereka menganggap bahwa dalam kegiatannya hanya belajar tidak ada keseruan seperti halnya jika bermain dengan teman sebaya di rumah. Kontribusi untuk lapangan pada kajian ini adalah memberi motivasi pada siswa Sekolah Minggu Buddha yang semula enggan mengikuti kegiatan menjadi lebih bersemangat dan lebih maksimal.Â