Detailed 2D Research Articles

New examples of ferroelectric nematic materials showing evidence for the antiferroelectric smectic-Z phase

We present a new ferroelectric nematic material, 4-((4′-((trans)-5-ethyloxan-2-yl)-2′,3,5,6′-tetrafluoro-[1,1′-biphenyl]-4-yl)difluoromethoxy)-2,6-difluorobenzonitrile (AUUQU-2-N) and its higher homologues, the molecular structures of which include fluorinated building blocks, an oxane ring, and a terminal cyano group, all contributing to a large molecular dipole moment of about 12.5 D. We observed that AUUQU-2-N has three distinct liquid crystal phases, two of which were found to be polar phases with a spontaneous electric polarization Ps of up to 6 µC cm–2. The highest temperature phase is a common enantiotropic nematic (N) exhibiting only field-induced polarization. The lowest-temperature, monotropic phase proved to be a new example of the ferroelectric nematic phase (NF), evidenced by a single-peak polarization reversal current response, a giant imaginary dielectric permittivity on the order of 103, and the absence of any smectic layer X-ray diffraction peaks. The ordinary nematic phase N and the ferroelectric nematic phase NF are separated by an antiferroelectric liquid crystal phase which has low permittivity and a polarization reversal current exhibiting a characteristic double-peak response. In the polarizing light microscope, this antiferroelectric phase shows characteristic zig-zag defects, evidence of a layered structure. These observations suggest that this is another example of the recently discovered smectic ZA (SmZA) phase, having smectic layers with the molecular director parallel to the layer planes. The diffraction peaks from the smectic layering have not been observed to date but detailed 2D X-ray studies indicate the presence of additional short-range structures including smectic C-type correlations in all three phases—N, SmZA and NF—which may shed new light on the understanding of polar and antipolar order in these phases.

Cytotoxic constituents from the fruit of Solanum aculeastrum

A new triterpene, aculeastrumone A (1), a new triterpene saponin aculeastrumoside A (2), and eleven known compounds (3–13) were isolated from MeOH/Water (80/20) extract of the fruits of Solanum aculeastrum (Solanaceae). Their structures were established by detailed 1D and 2D NMR spectroscopic studies and mass spectrometry. The isolated compounds were evaluated against three human cancer cells ((MCF-7 (breast cancer), NCI-H460 (lung cancer), and Hela (cervical cancer)) and normal human fibroblast (BJ) cell lines. Among them, saponins 2–5, 7–8, and Carpesterol 10 possess significant cytotoxic activity with IC50 ≤ 10 µM against the three cancer cell lines.

Phytochemicals from the Stem Bark of Calophyllum havilandii P. F. Stevens and their Biological Activities.

The genus Calophyllum from the family Calophyllaceae has been extensively investigated in the past due to its rich source of bioactive phenolics such as coumarins, chromanones, and xanthones. In this study, phytochemical investigation on the stem bark of Calophyllum havilandii has afforded a new 4-propyldihydrocoumarin derivative, havilarin (1) together with calolongic acid (2), caloteysmannic acid (3), isocalolongic acid (4), euxanthone (5), and β-sitosterol (6). The chemical structure of compound 1 was elucidated and established based on detailed spectroscopic techniques, including MS, IR, UV, 1D and 2D NMR. The results of anti-bacillus study indicated that the chloroform extract showed promising activities with MIC value ranging between 0.5 to 1 μg/mL on selected bacillus strains. Besides, the plant extracts and compounds 1-4 were assessed for their cytotoxicity potential on HL-7702 cell line. All the tested plant extracts and respective chemical constituents displayed non-cytotoxic activity on HL-7702 cell line.

Absolute calibration of the ratio of Xe/O two-photon absorption cross-sections for O-TALIF applications

The paper presents a calibration of the ratio of two-photon absorption cross-sections, σXe(2)/σO(2) , necessary for the absolute O-atom density measurements by two-photon absorption laser-induced fluorescence (TALIF) technique. To calibrate the ratio of the cross-sections, a special discharge with 100% dissociation of molecular oxygen, and so with a known ‘reference’ density of O-atom [O] ref=2⋅ [O2] was suggested. This is a nanosecond capillary discharge in N2:O2 mixtures with a few percent of oxygen at a reduced electric field of a few hundred of Townsend and specific deposited energy of about 1 eV mol−1. Voltage at the electrodes, electrical current in the plasma, longitudinal electric field and energy delivered to the gas were measured with 0.2 ns synchronisation. Additionally, radial distribution of emission of excited nitrogen molecules and gas temperature in the discharge and afterglow were obtained experimentally. Detailed 1D kinetic modeling was suggested to confirm complete O2 dissociation and to analyse the main reactions. By comparing the data measured by TALIF technique with the ‘reference’ density of oxygen atoms [O] ref , the ratio of the two-photon absorption cross-sections σXe(2)/σO(2) was determined.

Contact tracing of binary stars: Pathways to stellar mergers

Stellar mergers are responsible for a wide variety of phenomena such as rejuvenated blue stragglers, highly magnetised stars, spectacular transients, iconic nebulae, and stars with peculiar surface chemical abundances and rotation rates. Before stars merge, they enter a contact phase. Here, we investigate which initial binary-star configurations lead to contact and classical common-envelope (CE) phases and assess the likelihood of a subsequent merger. To this end, we computed a grid of about 6000 detailed 1D binary evolution models with initial component masses of 0.5 − 20.0 M⊙ at solar metallicity. Both components were evolved, and rotation and tides were taken into account. We identified five mechanisms that lead to contact and mergers: runaway mass transfer, mass loss through the outer Lagrange point L2, expansion of the accretor, orbital decay because of tides, and non-conservative mass transfer. At least 40% of mass-transferring binaries with initial primary-star masses of 5 − 20 M⊙ evolve into a contact phase; > 12% and > 19% likely merge and evolve into a CE phase, respectively. Because of the non-conservative mass transfer in our models, classical CE evolution from late Case-B and Case-C binaries is only found for initial mass ratios qi < 0.15 − 0.35. For larger mass ratios, we find stable mass transfer. In early Case-B binaries, contact occurs for initial mass ratios qi < 0.15 − 0.35, while in Case-A mass transfer, this is the case for all qi in binaries with the initially closest orbits and qi < 0.35 for initially wider binaries. Our models predict that most Case-A binaries with mass ratios of q < 0.5 upon contact mainly get into contact because of runaway mass transfer and accretor expansion on a thermal timescale, with subsequent L2-overflow in more than half of the cases. Thus, these binaries likely merge quickly after establishing contact or remain in contact only for a thermal timescale. On the contrary, Case-A contact binaries with higher mass ratios form through accretor expansion on a nuclear timescale and can thus give rise to long-lived contact phases before a possible merger. Observationally, massive contact binaries are almost exclusively found with mass ratios q > 0.5, confirming our model expectations. Because of non-conservative mass transfer with mass transfer efficiencies of 15 − 65%, 5 − 25%, and 25 − 50% in Case-A, -B, and -C mass transfer, respectively (for primary-star masses above 3 M⊙), our contact, merger, and classical CE incidence rates are conservative lower limits. With more conservative mass transfer, these incidences would increase. Moreover, in most binaries, the non-accreted mass cannot be ejected, raising the question of the further evolution of such systems. The non-accreted mass may settle into circumstellar and circumbinary disks, but could also lead to further contact systems and mergers. Overall, contact binaries are a frequent and fascinating result of binary mass transfer of which the exact outcomes still remain to be understood and explored further.

A tractable methodology for assessing the pressure scaling of sooting processes in a counterflow diffusion flame from 1 to 6 bar

A parametric study using ethylene as fuel was undertaken which examines the efficacy of concentration based and soot production rate (SPR) based parameters for assessing the pressure scaling of sooting processes in a counterflow diffusion flame. Two experimental designs pertaining to constant flow residence times (Case A), and constant carbon mass flux (Case B) were respectively implemented for pressures between 1 to 6 bars and across peak temperatures ranging from ∼2300−2600 K for Yf=Yox=0.35, ∼2100−2400 K for Yf=Yox=0.30, and ∼1800−2100 K for Yf=Yox=0.25 flames. A diffuse line-of-sight based extinction imaging diagnostic was employed for the measurement of soot concentrations. The evaluation of SPR follow a transport based coupling of inferred gaseous precursors, temperatures and velocity fields from detailed 1D OpenSMOKE++ simulations and soot concentrations from extinction measurements. The use of concentration based parameters, namely peak (∼p2.5−4.5) and integrated soot volume fractions (∼p2.1−3.9), is noted to be dependent on the Case A or B with little information discernible about the pressure effects in an experimental setting. The use of production rate based parameters, namely mean SPR (∼p2.2−3.4) removes the disparity of pressure scaling exponents across cases A and B but inherits the dependency to peak flame temperature, and gaseous precursor concentrations. An empirical fit of local SPR to acetylene and pyrene concentrations reveals a universal Arrhenius activation energy parameter in the high-temperature region (1300–2000 K) of the studied flames. The global activation energy is noted to remain roughly constant across varying peak flame temperatures, fuel flux, flow residence times and pressure. Consequently, we propose a soot yield parameter (Ω), calculated as the mean soot production rate normalized to acetylene and pyrene mass fractions which is noted to universally scale with pressure as Ω∼p1.7.

Optimal shaping of acoustic black holes for sound absorption in air

This article presents a systematic numerical study of the absorbing properties of acoustic black holes (ABHs) serving as an anechoic termination of waveguides. The study focuses on the sensitivity of ABHs’ absorbing performance to their profile and internal-structure parameters. The article compares numerical predictions from 1D model based on the Riccati equation with a detailed 2D model based on the linearized Navier-Stokes equations and the finite element method, finding good agreement among all results, especially for ABHs with fine internal structures. The mean value of the reflection coefficient modulus is used to quantify the ABH’s absorbing performance, and the article introduces the use of power-law functions and cubic splines to define the ABH’s shape function. An evolutionary algorithm is employed to optimize the ABH’s profile, resulting in improved absorbing performance. The numerical results suggest that the optimum shape is simple and more-or-less insensitive to other geometrical and internal-structure parameters.

3D Visualization of Proteins within Metal–Organic Frameworks via Ferritin‐Enabled Electron Microscopy

AbstractElectron tomography holds great promise as a tool for investigating the 3D morphologies and internal structures of metal‐organic framework‐based protein biocomposites (protein@MOFs). Understanding the 3D spatial arrangement of proteins within protein@MOFs is paramount for developing synthetic methods to control their spatial localization and distribution patterns within the biocomposite crystals. In this study, the naturally occurring iron oxide mineral core of the protein horse spleen ferritin (Fn) is leveraged as a contrast agent to directly observe individual proteins once encapsulated into MOFs by electron microscopy techniques. This methodology couples scanning electron microscopy, transmission electron microscopy, and electron tomography to garner detailed 2D and 3D structural interpretations of where proteins spatially lie in Fn@MOF crystals, addressing the significant gaps in understanding how synthetic conditions relate to overall protein spatial localization and aggregation. These findings collectively reveal that adjusting the ligand‐to‐metal ratios, protein concentration, and the use of denaturing agents alters how proteins are arranged, localized, and aggregated within MOF crystals.

Learning Space Transformation

This research aims to develop an interior design plan for the computer laboratory at SMKN 1 North Luwu. The research methodology employed in this study is research and development (R&D). The research process consists of several steps, including analyzing potential issues and challenges, accomplished through an extensive review of existing literature and on-site field studies. Data is collected through methods, including observations, interviews, and documentation. The content of the design development encompasses several crucial aspects. First, it involves the creation of a design concept for the laboratory, which is then translated into detailed 2D working drawings and 3D perspective drawings. These design proposals are rigorously assessed and validated by experts and practitioners. The outcomes of this research effort include a comprehensive interior design plan tailored specifically for the computer laboratory at SMKN 1 North Luwu. This design plan is presented through detailed 2D drawings and 3D modeling using V-ray SketchUp 2020. The validation process of the design resulted in a score of 141 with a percentage of 97.9%, indicating that the product design is highly suitable as an exemplary model for managing the computer laboratory at SMKN 1 North Luwu, with a classification of "excellent."

Disparate Contact Stress Behavior of Thermoplastic Gears against Steel Gear using 2D and 3D FEA

Based on the applications, the polymer gears are paired with different gear pair combinations such as Polymer – Polymer, Polymer – Steel, and Steel – Polymer. Finite Element Analysis is one of the effective techniques utilized to investigate the contact stress behavior of those gear pairs. Depending upon the selected conditions, such as two-dimensional finite element analysis with plane stress, plane strain conditions, and 3D FEA, the surface and subsurface contact stress occurrence between the gear pairs were observed. And, no proper explanations have arrived on such behaviors till date. Thus, the present study aimed to do a detailed 2D and 3D FE analysis for various thermoplastic gears with different gear pair combinations (S – P, P – S, and P – P) and investigated the occurrence of surface-subsurface stresses among the selected gear pairs. A comparison was done between the 2D and 3D FE analysis and validated with the assumed condition with regard to the face width. A gear with face widths of 5 and 20 mm has opted to reproduce the 2D plane stress and plane strain conditions, and their results were compared with 3D FEA. The contact stress data were extracted at 10 subsequent face width planes along the face width of a gear tooth. Higher directional stresses were noticed at the gear tooth mid-surface and reduced stress on the edges of the gear tooth for all the thermoplastic materials paired with all gear pairs. Surface stress for 2D FEA and subsurface stress for 3D FEA were detected for all the gear pair combinations. The maximum stress occurrence of 5 mm face width Steel – PP, Steel – ABS, Steel – DELRIN, ABS – Steel, DELRIN – Steel gear pairs exhibit a minimum depth value of 0.135 mm whereas 20 mm face width PC – Steel gear pair exhibits a maximum depth value of 0.3 mm. The maximum contact stress increases as a function of depth according to the proportional limit to elastic modulus dimensionless ratio.

Protonation equilibria of the tryptophan metabolite 8-hydroxyquinoline-2-carboxylic acid (8-HQA) and its precursors: A potentiometric and calorimetric comparative study

The protonation constants of quinaldic acid (QA), 8-hydroxyquinoline (8-HQ) and 8-hydroxyquinoline-2-carboxylic acid (8-HQA) were determined potentiometrically in KCl(aq) at I = 0.2 mol dm−3 at different temperatures (288.15 ≤ T/K ≤ 318.15). Their temperature dependence was modeled by the van't Hoff equation, which allowed the calculation of other thermodynamic parameters, such as ΔH0 and ΔS0. Protonation enthalpy changes were also experimentally determined by isothermal titration calorimetry (ITC) at T = 298.15 K in the same medium and ionic strength conditions. From the obtained results, it emerged that all stepwise protonation reactions for the three ligands are exothermic, with protonation constants decreasing with increasing temperature. Then, thermodynamic protonation parameters obtained by both approaches were critically analyzed and compared, evidencing that protonation enthalpy changes obtained experimentally by direct calorimetry are more accurate than those derived by the van't Hoff equation. However, the latter approach proved useful to evidence possible variability of this thermodynamic parameter with temperature, thus allowing the eventual calculation of the corresponding ΔCp. Furthermore, on the basis of both the analysis of the obtained parameters and the results of detailed 1D and 2D 1H NMR studies, it was possible to unequivocally determine the protonation sequence of the different functional groups of 8-HQA (as well as QA and 8-HQ): from basic to acidic pH, the first group to undergo protonation is the phenolate, followed by the quinolinic nitrogen and, finally, by the carboxylate.

The Polyketides with Antimicrobial Activities from a Mangrove Endophytic Fungus Trichoderma lentiforme ML-P8-2.

Five new polyketides, including two chromones (1-2), two phenyl derivatives (4-5), and a tandyukusin derivative (6), along with five known polyketides (3 and 7-10) were isolated from mangrove endophytic fungus Trichoderma lentiforme ML-P8-2. The planar structures of compounds were elucidated via detailed 1D, 2D NMR, and HR-ESI-MS analysis. ECD spectra, optical rotation values calculation, and alkali hydrolysis were applied in the determination of the absolute configuration of the new compounds. In bioassays, 6 and 9 exhibited promising antifungal activities against Penicillium italicum, with an MIC value of 6.25 μM for both compounds. Moreover, 3 displayed moderate AChE inhibitory activity with an IC50 value of 20.6 ± 0.3 μM.

Neutrino signatures of 100 2D Axisymmetric Core-Collapse Supernova Simulations

ABSTRACT We present in this paper a public data release of an unprecedentedly large set of core-collapse supernova (CCSN) neutrino emission models, comprising 100 detailed 2D axisymmetric radiation-hydrodynamic simulations evolved out to as late as ∼5 s post-bounce and spanning an extensive range of massive-star progenitors. The motivation for this paper is to provide a physically and numerically uniform benchmark data set to the broader neutrino detection community to help it characterize and optimize subsurface facilities for what is likely to be a once-in-a-lifetime galactic supernova burst event. With this release, we hope to (1) help the international experiment and modelling communities more efficiently optimize the retrieval of physical information about the next galactic CCSN, (2) facilitate the better understanding of core-collapse theory and modelling among interested experimentalists, and (3) help further integrate the broader supernova neutrino community.

Computational investigation on daily, monthly and seasonal energy performances and economic impact through a detailed 2D FEM model of an earth to air heat exchanger coupled with an air conditioning system in a continental climate zone

Computational investigation on daily, monthly and seasonal energy performances and economic impact through a detailed 2D FEM model of an earth to air heat exchanger coupled with an air conditioning system in a continental climate zone

Two-dimensional model of ion transport in composite membranes active layers with TEM-scanned morphology

Ion rejection by composite membranes for RO/NF is performed by an ultrathin polyamide active layer (AL) with non-uniform thickness. Current models explain the solute and water fluxes by concentration and potential in AL of uniform properties, there are studies showing the effects of its topology on permeability. We developed a two-dimensional extension of the solution-friction model, coupling ion and water transport in irregularly-shaped charged AL, with geometry extracted from TEM images. Simulations indicated that AL with pronounced roughness lead to highly non-uniform distribution of ionic fluxes and lead to NaCl permeability greater than obtained by uniform layers. The transmembrane pressure and membrane charge can shift the relative dominance of ion transport mechanisms. In weakly charged membranes diffusion dominates, even at high water fluxes. Electromigration can counteract the convective flux in highly charged membranes. The model revealed the possibility of circular ionic currents within/around the AL. The response of the 2D model to variations in flux and salinity can be identical to the response of a 1D model, providing that the 1D model uses an appropriate equivalent membrane thickness. We provided a method to convert the detailed 2D geometry into a single number that can be computed from images' active layers.

Radiative flamelet generated manifolds for solid fuel flame spread in microgravity

Recently, U-shape flammability maps have been constructed showing minimal oxygen concentration vs. flame strain for opposed flame spread in microgravity. Due to the absence of buoyancy in microgravity, flammability experiments require a microgravity environment and are costly to perform. Alternatively, detailed numerical simulations can be conducted to explore the flammability maps if sufficiently detailed chemistry mechanisms and radiation models are available. The purpose of this study is to develop such an approach and to explore the viability of using flamelet modeling descriptions. For this effort, a detailed two-dimensional (2D) flame spread model is developed that includes multi-step complex chemistry and fully coupled radiation heat transfer. The model is validated against measurements using the NASA BASS data and is shown to predict reasonable flame spread rates over a range of far-field oxygen levels. Next, newly developed coupled radiative flamelet generated manifolds (CR-FGM’s) are created using a simplified one-dimensional (1D) descriptions that include a quasi-coupled, fuel boundary that is shown to be critically important for capturing the spatially dependent variation of mixture fraction on fuel surfaces. Differences between the 2D model data and the CR-FGM’s are then identified to be from flame-wall interactions and curved flame structure effects. These differences are addressed using an a-priori error analysis conducted for various intermediate species comparing detailed 2D simulations with the CR-FGM. Results show the CR-FGM’s are capable in predicting the wide range of chemical states for most of the flow regions.

Cytosporones W and X: Two Mutually Converting Epimers from a Mangrove Endophytic Fungus Diaporthe sp. ZJHJYZ-1.

Two new octaketides, cytosporones W (1) and X (2), along with eight known cytosporone derivatives [(±)-3-9], were isolated from mangrove endophytic fungus Diaporthe sp. ZJHJYZ-1. Compounds 1 and 2 were a pair of epimers, whose configuration of C-1 could mutually convert, causing racemization of the lactone ring. The planar structures of compounds were elucidated through detailed 1D, 2D NMR, and HR-ESI-MS analysis. ECD spectra comparison and modified Mosher ester method were applied to determine the absolute configuration of 1 and 2. In bioassays, (±)-3 exhibited promising inhibitory activities against Bacillus subtilis, Pseudomonas aeruginosa, and Penicillium italicum with MIC, respectively, for 12.5, 12.5, and 3.13 μM.

Detailed characterization of neural selectivity in free viewing primates

Fixation constraints in visual tasks are ubiquitous in visual and cognitive neuroscience. Despite its widespread use, fixation requires trained subjects, is limited by the accuracy of fixational eye movements, and ignores the role of eye movements in shaping visual input. To overcome these limitations, we developed a suite of hardware and software tools to study vision during natural behavior in untrained subjects. We measured visual receptive fields and tuning properties from multiple cortical areas of marmoset monkeys who freely viewed full-field noise stimuli. The resulting receptive fields and tuning curves from primary visual cortex (V1) and area MT match reported selectivity from the literature which was measured using conventional approaches. We then combined free viewing with high-resolution eye tracking to make the first detailed 2D spatiotemporal measurements of foveal receptive fields in V1. These findings demonstrate the power of free viewing to characterize neural responses in untrained animals while simultaneously studying the dynamics of natural behavior.

Structurally Diverse Triterpene-26-oic Acids as Potential Dual ACL and ACC1 Inhibitors from the Vulnerable Conifer Keteleeria fortunei.

A preliminary phytochemical investigation on the 90% MeOH extract from the twigs and needles of the vulnerable conifer Keteleeria fortunei led to the isolation and characterization of 17 structurally diverse triterpen-26-oic acids, including nine previously undescribed ones (fortunefuroic acids A-I, 1-9) featuring a rare furoic acid moiety in the lateral chain. Among them, 1-5 are uncommon 9βH-lanostane-type triterpenoic acids. Friedo-rearranged triterpenoids 6 and 7 feature a unique 17,14-friedo-lanostane skeleton, whereas 9 possesses a rare 17,13-friedo-cycloartane-type framework. Their structures and absolute configurations were elucidated by extensive spectroscopic (e.g., detailed 2D NMR) and computational (NMR/ECD) calculations and the modified Mosher's method. In addition, the absolute structure of compound 1 was ascertained by single-crystal X-ray diffraction analyses. Fortunefuroic acids B (2), G (7), and I (9), along with isomangiferolic acid (12) and 3α,27-dihydroxycycloart-24E-en-26-oic acid (14), exhibited dual inhibitory effects against the adenosine triphosphate (ATP)-citrate lyase (ACL, IC50s: 5.7-11.4 μM) and acetyl-CoA carboxylase 1 (ACC1, IC50s: 7.5-10.5 μM), both of which are key enzymes for glycolipid metabolism. The interactions of the bioactive triterpenoids with both enzymes were examined by molecular docking studies. The above findings reveal the important role of protecting plant species diversity in support of chemical diversity and potential sources of new therapeutics for ACL-/ACC1-associated diseases.

Timing of the Cenozoic magmatic intrusions in the offshore Tanga Basin, Tanzania: correlation to age equivalent deposits in the Eyasi-Wembere Basin and their implications for petroleum potential

Abstract The offshore Tanga Basin of north-eastern Tanzania contains Cenozoic sedimentary successions that have been poorly studied. The basin development was due to an interplay of multiple factors including periods of active fault movement linked to the East African Rift system (EARs) which influenced the Cenozoic development of the offshore Tanga Basin. The EARs recorded several discrete tectonic episodes that were associated with magmatic activities and massive volcanism. However, there is no report on the possible presence of magmatic intrusions indicative of magmatic activities and volcanism in the history of the Tanga Basin. Timing of occurrence and distribution of magmatic intrusions are among the key components needed to evaluate the petroleum potential of the basin. A detailed 2D qualitative seismic interpretation, coupled with core logging data and analysis of elemental proxies, has been employed to evaluate the petroleum potential of the Cenozoic successions of the offshore Tanga Basin considering the presence and timing of occurrence of the magmatic intrusions. These used data and the associated interpretation techniques have not been used before to meet similar objectives. Both core logging and elemental proxies are newly collected information used in this study. Results suggest that the Tanga Basin has been variedly intruded by magmatic sills and dikes. Seismic well tie and correlation to age-equivalent deposits across the onshore successions in the EWB revealed that the volcanic events occurred during tectonic episodes that influenced the development of the East African Rift basins. Seismic interpretation also suggests that these tectonic episodes occurred possibly during the Miocene, Pleistocene and Holocene periods when magmatic intrusions are believed to have promoted source rock maturation and facilitated the formation of structural elements for petroleum preservation.