Synthetic Field Research Articles

Recent Progress for the Synthesis of Pyrrole Derivatives – An Update

Abstract: Pyrrole is a versatile heterocyclic moiety exhibiting a wide range of pharmacological actions with high therapeutic value. The importance of pyrrole in the pharmaceutical field lies in its versatility, selectivity, and biocompatibility, and these properties make it a valuable tool for drug design and development. The pyrrole moiety is a fundamental building block for many biologically active molecules and has gathered significant attention in the fields of medicinal and organic chemistry; hence, its synthesis has been a crucial area for research. There are various conventional as well as modern approaches to acquiring a series of pyrrole scaffolds, with a wide range of attractive features and drawbacks pertaining to each approach. An extensive amount of literature must be studied to compare the best synthetic routes. This article highlights the applications of pyrrole derivatives in various fields, such as drug discovery, material science, and catalysis, and provides an overview of modern synthetic pathways that include metals, nanomaterials, and complex heterogeneous catalysed methods for pyrrole derivatives. Special emphasis is given to the use of green chemistry principles like green solvent-based methods, microwave-aided methods, and solvent-free methods in the synthesis of pyrroles, with the recent developments and prospects in the synthetic and organic chemistry fields. Overall, this review article provides a comprehensive overview of the synthesis of pyrroles and complies with all the possible developments in the synthetic routes for pyrroles within 2015– 2022. Among all, the reactions catalysed by proline, copper oxides, and oxones have been shown to be the most effective synthetic route for pyrrole derivatives at mild reaction conditions and with excellent yields. This information will be helpful for researchers interested in the development of new pyrrole-based compounds. The categorization in this review provides an easy means for the reader to rationally select the best possible synthetic method for pyrrole derivatives.

A theoretical analysis of the logging-while-drilling dipole acoustic reflection measurement

Post-drilling wireline acoustic single-well imaging technology can now detect geological structures tens of meters away from boreholes. Further development of this single-well imaging technology in the logging-while-drilling (LWD) environment will have significant values in real-time applications such as geosteering and reservoir navigation. Based on the wireline imaging application, we propose a new method for the LWD application. In wireline imaging, the four-component (4C) dipole acoustic data are azimuthally rotated to scan the reflectors around the borehole. In LWD, azimuthal scanning is achieved by drilling rotation such that the 4C dipole system in the wireline is replaced by a one-dipole-source and two-receiver LWD system, where the two receivers are mounted on opposite sides of the drill collar. For the LWD application, we first developed the theory for LWD dipole shear-wave reflection imaging and validated the theory using 3D finite-difference waveform modeling. Using the analytical solution, we analyzed the far-field radiation directivity of an acoustic LWD dipole source and the effect of drilling rotation on the shear-wave reflection imaging using the LWD acoustic system. The LWD analysis results show that, for fast formations, the SH-wave is the dominant component for imaging, whereas for slow formations, the P-wave becomes important and can be used for imaging. Our results also indicate that the reflection data acquired by the system are affected by the speed of drilling rotation. The take-off azimuth at the wave radiation may be different from the incident azimuth at the wave reception. Knowing the rotation speed, this azimuth difference can be corrected. A further advantage of using the oppositely mounted receivers is that the reflected wave arrives earlier (later) at the front (back)-side receiver; thus, the arrival time difference between the receivers can be used to eliminate the 180°-azimuth ambiguity of dipole acoustic imaging. For reflection imaging, using the proposed LWD system configuration, we tested its azimuth sensitivity and validated its 180°-ambiguity solution using synthetic LWD and field wireline dipole data. The results of this work, therefore, provide a theoretical foundation for the development of the LWD acoustic reflection imaging system.

Amplitude variation with azimuth direct inversion for effective pressure-sensitivity parameters in horizontal transversely isotropic media

Effective pressure prediction is of great significance for fracturability evaluation in unconventional reservoirs. Quantitative characterization of effective pressure remains a great challenge in the inversion prediction of subsurface media. Our goal is to develop a novel Bayesian amplitude varying with azimuth (AVAZ) inversion method to estimate fracture weaknesses and effective pressure for a horizontal transversely isotropic (HTI) medium. Using Schoenberg’s linear slip model and pore space compressibility theory, an anisotropic saturated stiffness matrix directly characterized by effective pressure is derived based on a weak-contrast interface separating two weakly anisotropic half-spaces of HTI medium. Based on the perturbation stiffness matrix and scattering theory, we derive a PP-wave reflection coefficient approximation directly characterized by fracture weaknesses and effective pressure-sensitive parameters, which establishes a quantitative relationship between seismic reflection coefficient and effective pressure. The analysis of accuracy and sensitivity is performed to verify the reliability and applicability of the constructed reflection coefficient. And then, the azimuth-amplitude-difference forward solver is constructed based on seismic reflection coefficients to eliminate the influence of isotropic background perturbations on seismic reflection coefficients and reduce the condition number of the forward solver. Finally, we present a novel Bayesian azimuth-amplitude-difference AVAZ inversion method for transversely isotropic media constrained by Cauchy and Gaussian regularization to directly estimate the fracture weaknesses and effective pressure-sensitive parameters. The application of synthetic data and field data verifies that the inversion results are in good agreement with the actual data, indicating that the method can effectively realize the stable prediction of anisotropic parameters and effective pressure-sensitive parameters of complex media.

A nonlinear inversion method for Young’s modulus and shear modulus based on the exact Zoeppritz equations

IntroductionYoung’s modulus and shear modulus are essential mechanical parameters for evaluating subsurface rocks, playing a pivotal role in the exploration and development of unconventional resources. Young’s modulus indicates the brittleness of the reservoir, while shear modulus determines the ease of fracturing rock layers.MethodsTraditional methods estimate these moduli through indirect calculations and approximate expressions, which are prone to cumulative errors and rely on multiple assumptions, reducing inversion accuracy. This paper presents a direct inversion method for acquiring of Young’s modulus and shear modulus using the exact Zoeppritz equations, integrated within a Bayesian framework for pre-stack inversion. The quantum particle swarm optimization (QPSO) algorithm is introduced to achieve a nonlinear solution to the objective function.ResultsTests on synthetic and actual field data demonstrate the feasibility and effectiveness of the proposed method, yielding more accurate inversion results compared to traditional methods.DiscussionThese findings provide valuable insights for predicting reservoir brittleness and characterizing reservoirs in unconventional shale gas exploration and development.

Rayleigh wave ellipticity from ambient noise: A practical method for monitoring seismic velocity variations in the near-surface

This study explores the feasibility and limitations of using Rayleigh wave (Rg) ellipticity for noise-based seismic monitoring at near-surface depths (4–70 m). We use the degree of polarization (DOP) method to extract the Rayleigh wave ellipticity from seismic noise recordings, employing normalized cross-correlation and cross-covariance coefficients to quantify ellipticity variations over time. Synthetic models and field data from three distinct case studies—Garner Valley, California; Riotinto mine, Spain; and the 2011 submarine volcanic eruption on El Hierro Island, Canary Islands—validate our approach. In these field applications, our method effectively tracks the seasonality of the shallow groundwater levels in Garner Valley, monitors pore pressure variations at the tailings dam of Riotinto mine, and detects volcanic induced changes on El Hierro, demonstrating robust performance even with variable noise sources. Our results indicate that Rayleigh wave ellipticity is a versatile tool for subsurface monitoring, capable of detecting velocity changes across a broad depth range. Our methodology represents a new independent and non-interferometric approach that enhances the detection of subsurface changes while improving resolution and exploration depth in seismic monitoring techniques.

The Role of Cultural Heritage in The Development of Tourism and Some Cultural Industries in Vietnam

Many nations now view the cultural industry as a significant role in the country's cultural life and as a vital economic sector supporting sustainable development. Vietnam has an affluent cultural history with diverse cultural identities and is valuable in every way. The development of various cultural industries benefits greatly from the resources provided by cultural heritages. In order to elucidate the significance of cultural heritage in the growth of particular cultural industries, such as music, film, and cultural tourism, we employ synthetic analysis techniques and field research in this article. According to the research findings, cultural heritages are becoming important resources for the growth of cultural tourism, giving travellers motivation to travel, learn, and carry out research. Cultural heritage also provides resources and inspiration for music and film production, meeting the public's needs for cultural entertainment. The article makes inferences about the value of cultural heritage; development constraints, and potential solutions for preserving and enriching cultural heritage within the cultural industry. It also provides ways to improve human resources in the fields of music, film, and cultural tourism.

Seismic fault detection with sliding windowed differential cepstrum–based coherence analysis

AbstractCepstral decomposition is beneficial for highlighting certain geological features within the particular quefrency bands which may be deeply buried within the wide quefrency range of the seismic data. Converting seismic traces into the corresponding cepstrum components can better analyse some characteristics of underground strata than the traditional spectral decomposition methods. We propose the sliding windowed differential cepstrum–based coherence analysis approach to delineate the fault features. First, the data are decomposed using a sliding windowed differential cepstrum, which results in multi‐cepstrum data of corresponding quefrency of certain bandwidth. These different multi‐cepstrum data may highlight the different stratigraphic features in a certain quefrency band. We select the first‐order common quefrency volume as the featured attribute. Then, eigenstructure‐based coherence is applied on the first‐order common quefrency data volume to statistically obtain the fault detection result with a finer and sharper image. Synthetic data and field data examples show that the proposed method has the ability to better visualize all the possible subtle and minor faults present in the data more accurately and discernibly than the traditional coherence method. Compared with the ant‐tracking method, the proposed method is more effective in revealing the major faults. It is hoped that this work will complement current fault detection methods with the addition of the cepstral‐based method.

Expansion dynamics of Bose-Einstein condensates in a synthetic magnetic field

Expansion dynamics of Bose-Einstein condensates in a synthetic magnetic field

In vitro human oral bioaccessibility assessment of hazardous chemicals, including N, N′-substituted-p-phenylenediamines, coming from recycled tire crumb rubber

Tires, apart from being formed by rubber and filling materials, contain organic compounds added to make them resistant and durable. The widely use of recycled tire crumb rubber (RTCR), main product of the shredding process of end-of-life tires, can cause human exposure to these chemicals due to its use in synthetic football fields and kid's playgrounds. In 2023, the European Commission banned the use of recycled tire crumb rubber in synthetic fields, giving eight years to replace the used material. This study intends to assess the oral bioaccessibility of antiozonants, crosslinking and vulcanizer agents present in RTCR. With this purpose, the Unified Bioaccessibility Method (BARGE) was used to simulate the material ingestion. RTCR is put into contact with the four simulated biological fluids including saliva, gastric and duodenal juice and bile, attempting to simulate human digestion. Afterwards, the organic compounds present in the fluid need to be extracted and Solid-phase extraction (SPE) was the technique selected after being optimized to obtain the best extraction conditions. Ultrasound assisted extraction was performed to evaluate the total concentration of the target compounds in the crumb rubber matrixes. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was employed to identify and quantify the target compounds. The results showed the bioaccessibility of all the studied analytes, with values ranging from 0.1 % up to 70 %. Benzothiazole was the compound with the highest bioaccessibility with a mean value of 40 % and concentrations reaching 32000 ng g−1 in the bioaccessible fraction. N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine and its transformation product ((4-Methylpentan-2-yl)amino)-5-(phenylamino)cyclohexa-2,5-diene-1,4-dione) showed an average bioaccessibility of 0.1 % and 1.8 %, respectively, the latter being present in all the analysed samples.

A high-efficiency Q-compensated pure-viscoacoustic reverse time migration for tilted transversely isotropic media

The attenuation and anisotropy characteristics of real earth media give rise to amplitude loss and phase dispersion during seismic wave propagation. To address these effects on seismic imaging, viscoacoustic anisotropic wave equations expressed by the fractional Laplacian have been derived. However, the huge computational expense associated with multiple Fast Fourier transforms for solving these wave equations makes them unsuitable for industrial applications, especially in three dimensions. Therefore, we first derived a cost-effective pure-viscoacoustic wave equation expressed by the memory-variable in tilted transversely isotropic (TTI) media, based on the standard linear solid model. The newly derived wave equation featuring decoupled amplitude dissipation and phase dispersion terms, can be easily solved using the finite-difference method (FDM). Computational efficiency analyses demonstrate that wavefields simulated by our newly derived wave equation are more efficient compared to the previous pure-viscoacoustic TTI wave equations. The decoupling characteristics of the phase dispersion and amplitude dissipation of the proposed wave equation are illustrated in numerical tests. Additionally, we extend the newly derived wave equation to implement Q-compensated reverse time migration (RTM) in attenuating TTI media. Synthetic examples and field data test demonstrate that the proposed Q-compensated TTI RTM effectively migrate the effects of anisotropy and attenuation, providing high-quality imaging results.

Simulated Directional Wave Spectra of the Wind Sea and Swell under Typhoon Mangkhut

A third-generation wave model is driven by the synthetic wind field combined with the revised Holland wind and surface wind product from the National Centers for Environmental Prediction (NCEP). The temporal and spatial characteristics of the wind waves and swell during the typhoon are studied, as well as the responses of their wave energy spectra to the source terms. The results show that the typhoon waves have a more complicated asymmetric structure than the wind field, and the maximum significant wave height is always located on the right side of the direction along which the typhoon is moving, where wind waves are dominant, due to the extended fetch. The nonlinear wave–wave interaction helps to redistribute the energy of the wind seas at a high frequency to the remotely generated swells at a low frequency, ensuring that the typhoon wave’s energy spectrum remains unimodal. This process occurs in regions without extended fetch, and a similar continued downshift in frequency as the wave–wave interaction occurs for the wind input as well when the waves outrun the typhoon, due to the nonlinear coupling between the wind and growing swells.

Detección de roca intrusiva alterada mediante tomografía de resistividad eléctrica: El caso del área de San Luis, zona central de Panamá

This work investigates the potentiality of the 2D electrical resistivity tomography method to delineate an altered intrusive rock domain. The detection and characterization of such altered domains are crucial to understanding local hydrogeological conditions. Here, the target is the San Luis area, located in the northern part of the Estibaná River watershed, within the Los Santos Province in the central region of the Isthmus of Panama. First, a detailed geological survey was carried out to better constrain the tectonic structures. Then, two geological sections were developed based on two 2D electrical resistivity tomographies. A geoelectrical simulation process was conducted in both sections to set theoretical models whose model responses (synthetic field data set) would be consistent with the observations. After appropriate selection of the inversion parameters by using the Boundless Electrical Resistivity Tomography (BERT) code, the observations were processed, resulting in low calculation errors (2 < 0.51). Based on the superficial geological information and the results of the geophysical modelling, two profiles were established, depicting the lateral and in-depth distribution of rocks and sediments. The limit of the Ocú-Parita fault zone was identified as well. The results of the 2D inversion of the synthetic data, obtained with the established theoretical models, are consistent with the 2D inversion of the observations. Electrical resistivity tomography studies can be useful in establishing groundwater management models, particularly in areas that experience severe water scarcity during the dry season.

In Situ Efficient End Functionalization of Polyisoprene by Epoxide Compounds via Neodymium-Mediated Coordinative Chain Transfer Polymerization.

The Nd-mediated coordinative chain transfer polymerization (CCTP) of dienes represents one of the state-of-the-art techniques in the current synthetic rubber field. Besides having well-controlled polymerization behaviors as well as high atom economies, it also allows for the generation of highly reactive Al-capped polydienyl chain-ends, which hold great potential, yet much less explored up to date, in achieving end functionalization to mimic the structure of natural rubber. In this study, we demonstrate an efficient in situ method to realize end-functionalizing polyisoprene by introducing epoxide compounds into a CCTP system. The end functionalization efficiency was 92.7%, and the obtained polymers were systematically characterized by 1H NMR, 1H,1H-COSY NMR, DOSY NMR, and MALDI TOF. NMR studies revealed that a maximum of two EO units were introduced to the chain ends, and based on density functional theory (DFT) studies, an energy barrier of 33.3 kcal/mol was required to be overcome to open the ring of the EO monomer. Increasing the ratio of [Ip]/[Nd] resulted in gradually increased viscosities for the reaction medium and therefore gave rise to an end functionalization efficiency that decreased from 92.7% to 74.2%. The end hydroxyl group can also be readily converted to other functionalities, as confirmed by NMR spectroscopy.

Chiral dynamics of ultracold atoms under a tunable SU(2) synthetic gauge field

Chiral dynamics of ultracold atoms under a tunable SU(2) synthetic gauge field

Poldw: A Python code to denoise 3C seismic data with a new threshold-free polarization technique

We present a Python code that implements a novel threshold-free polarization strategy for removing random noise from 3C linearly polarized seismic data. The code, which we refer to as polarization denoising through windowing (poldw), uses closed-form formulas along sliding windows that span the data to determine the optimal rotation angles that allow the transfer of most of the signal energy to a given component. The denoised 3C data are obtained after canceling out the other two components, which are assumed to contain predominantly noise, and then rotating back. The method is simple and efficient because it only requires setting the sliding window length. Synthetic and microseismic field data examples show the method’s effectiveness, which significantly improves the signal-to-noise ratio without the need for threshold-based polarization filters. Therefore, these filters can be pipelined in the rotation-based strategy for additional noise removal if necessary. When the data set contains nonlinearly polarized data or significant nonrandom noise, the method is likely to fail. For robustness against non-Gaussian noise and outliers, poldw allows for the use of alternative norms similar to the [Formula: see text]- or [Formula: see text]-norms instead of the energy. In addition to the code, we provide a Jupyter notebook to illustrate the method step by step and reproduce the results of the field data example.

Better stopping through cross validation in an iterative ensemble smoother: A perspective from supervised machine learning

Iterative ensemble smoothers (IES) are among the popular reservoir data assimilation (RDA) algorithms for reservoir characterization. The actual deployment of an IES algorithm requires implementing certain stopping criteria, normally adopted for runtime control (e.g., by stopping the IES when it reaches the maximum number of iterations) and/or safeguarding the RDA performance (e.g., by preventing the simulated data from overfitting the actual observations). In practice, for various reasons, it is often challenging for existing stopping criteria to simultaneously achieve both purposes. One noticeable issue, as illustrated in this work, is that in many situations, the qualities of the estimated reservoir models may already start to deteriorate before a conventional stopping criterion activates to terminate the iteration process. Following this observation, one practically important question arises: Is it possible to further improve the efficacy of the IES algorithm by designing a different stopping criterion so that the IES can stop earlier, saving computational costs while achieving better RDA performance?As one of the rare attempts in the community, this work aims to investigate the use of a new IES stopping criterion that has the potential to provide an affirmative answer to the above question. In this regard, our main idea is based on the concept of cross validation (CV), routinely adopted in supervised machine learning (SML) problems for early stopping to prevent SML models from overfitting the training data. Despite the noticed similarities between RDA and SML problems, some fundamental differences exist, making it fail to work well if one directly extends a vanilla CV procedure from SML to RDA. To tackle this identified challenge, we design an efficient CV procedure tailored for RDA problems, and inspect the performance of an IES algorithm equipped with this CV procedure (IES-CV) in both synthetic and real field case studies. Our numerical investigation indicates that the IES-CV algorithm achieves promising RDA performance in all case studies, confirming the possibility that with the aid of a proper stopping criterion, an IES algorithm can terminate at an appropriate iteration step with near-optimal RDA performance. Beyond these numerical findings, it is also our hope that the current work may help improve the best practices of applying IES to RDA problems, taking advantage of the effective, CV-based stopping criterion.

Hybrid machine learning framework for multi-well trajectory optimization in an unconventional field

The well placement problem in the petroleum industry is usually solved by integrating an optimizer with a reservoir simulation model. This is a time-consuming approach requiring thousands of simulation runs depending on the complexity of the reservoir system. This paper introduces two well placement optimization models: a Fast-Marching Model (FMM) based on fluid flow physics and a Hybrid Model integrating reservoir simulations and FMM results with a gradient boosting algorithm. These models prioritize speed and accuracy when integrated with genetic algorithm optimization, demonstrated using a synthetic unconventional field. From 290 randomly selected locations across the synthetic unconventional field, simulation runs were performed to determine cumulative gas production and used as ground truth. Using reservoir properties at these locations as inputs, Relative Opportunity Ranking (ROR) maps were generated using the FMM and Hybrid Model approaches. The ROR maps were then linked with a genetic algorithm to determine optimal well locations, iteratively updating ROR maps with penalty maps until all wells were appropriately placed. Results indicated that the standalone FMM generated ROR maps were highly correlated with the simulation results. Time complexity analysis revealed that both models were significantly faster than traditional methods, with the FMM independent of simulation and the Hybrid Model requiring only about 290 simulation runs. Ultimately, these models have shown tremendous potential for integration into current reservoir engineering workflows, reducing decision-making times in both greenfield and brownfield scenarios.

Collective Synthesis of Furanocoumarin Natural Products Through a Radical‐mediated Construction of Furanocoumarin Skeletons

AbstractFuranocoumarins are attractive targets in the synthetic organic and medicinal chemistry field because of their structural diversity and interesting biological properties. Herein, we describe the synthesis of furanocoumarin natural products from common furanocoumarin skeletons. A key step was a novel intramolecular radical cyclization onto nitrile to synthesize angular and linear franocoumarins, which was optimized by reacting iodocoumarin derivatives in the presence of (Me3Si)3SiH and oxygen. These compounds served as intermediates in the syntheses of vaginidiol, vaginidin, oroselol, multivittan D, gaudichaudine, oreoselone, peucedanin, and smyrindiol, successfully demonstrating the versatility of the intermediates and utility of the radical cyclization method for accessing furanocoumarin natural products.

Surface Rupture and Fault Characteristics Associated With the 2020 Magnitude (MW) 6.6 Masbate Earthquake, Masbate Island, Philippines

AbstractOn 18 August 2020, Masbate Island was struck by a magnitude (MW) 6.6 earthquake. This seismic event represents the second occurrence of a strong earthquake (M > 6) in 17 years, emphasizing the necessity for further investigation into the characteristics of this event. In this study, we employ Interferometric Synthetic Aperture Radar, seismicity analysis, and field investigations to comprehensively characterize the coseismic and postseismic slip associated with the event. Our findings reveal a 50‐km‐long fault rupture along the Masbate segment of the Philippine Fault, with ∼23 km surface rupture mapped onshore, despite the occurrence of interseismic creep. The slip distribution demonstrates decreasing displacements northwestward toward the creeping section, with a maximum left‐lateral displacement of 0.97 m near the epicenter. Toward the southeast offshore, the rupture terminates at a left stepover of a fault. While the surface rupture appears relatively straight and narrowly concentrated, the secondary ruptures and mapped offshore faults reveal a more complex transtensional fault structure in the southeastern part of Masbate Island. This fault complexity represents an asperity that facilitates high‐stress accumulation and rupture initiation. Postseismic slip persists for several months along the onshore creeping segment. Based on comprehensive measurements of both cumulative and coseismic slip along the Masbate fault segment, we calculate a slip rate ranging between 2.8 and 3.8 cm/year and a recurrence interval of 16–41 years for earthquakes similar to the 2020 earthquake. Our study highlights how heterogeneity in fault properties, including geometry and coupling state, influences the distribution of slip and magnitude of earthquakes. The 2020 Masbate earthquake provides valuable insights into the rupture dynamics and fault behavior of the Philippine Fault in the Masbate region.

Photo-Activated Carbon Dots as Catalysts in Knoevenagel Condensation: An Advance in the Synthetic Field

Photoinduced chemical reactions and the development of new materials represent a current and significant topic. We present a sustainable and eco-friendly approach to the Knoevenagel condensation reaction involving carbonyl and active methylene compounds. Our method utilizes photo-activated carbon dots (CDs) derived from 5-hydroxymethylfurfural (5HMF) within an aqueous medium and does not require acidic, basic, or thermal conditions. This protocol operates effectively with aromatic, aliphatic, and heteroaromatic aldehydes and ketones. The 5HMF-derived-CDs can be reused four times without significant loss of activity. Moreover, this methodology is suitable for scaling up reactions, thereby highlighting its potential for industrial applications.