bluuebunny/crossref_metadata_2025_split huggingface dataset:
Innovative applications of subgrade biogeochemical reactors: Three case studies
Authors: Gamlin Jeff , Cox Jeremy , Castor Andrew 
Published: March 2019

AbstractSubgrade biogeochemical reactors (SBGRs) are an in situ remediation technology shown to be effective in treating contaminant source areas and groundwater hot spots, while being sustainable and economical. This technology has been applied for over a decade to treat chlorinated volatile organic compound source areas where groundwater is shallow (e.g., less than approximately 30 feet below ground surface [ft bgs]). However, this article provides three case studies describing innovative SBGR configurations recently developed and tested that are outside of this norm, which enable use of this technology under more challenging site conditions or for treatment of alternative contaminant classes. The first SBGR case study addresses a site with groundwater deeper than 30 ft bgs and limited space for construction, where an SBGR column configuration reduced the maximum trichloroethene (TCE) groundwater concentration from 9,900 micrograms per liter (μg/L) to <1 μg/L (nondetect) within approximately 15 months. The second SBGR is a recirculating trench configuration that is supporting remediation of a 5.7‐acre TCE plume, which has significant surface footprint constraints due to the presence of endangered species habitat. The third SBGR was constructed with a new amendment mixture and reduced groundwater contaminant concentrations in a petroleum hydrocarbon source area by over 97% within approximately 1 year. Additionally, a summary is provided for new SBGR configurations that are planned for treatment of additional classes of contaminants (e.g., hexavalent chromium, 1,4‐dioxane, dissolved explosives constituents, etc.). A discussion is also provided describing research being conducted to further understand and optimize treatment mechanisms within SBGRs, including a recently developed sampling approach called the aquifer matrix probe.
Nuclear magnetic resonance logging: Example applications of an emerging tool for environmental investigations
Authors: Spurlin Matthew S. , Barker Brent W. , Cross Bradley D. , Divine Craig E. 
Published: March 2019

AbstractNuclear magnetic resonance (NMR) geophysical tools have been widely used in the petroleum exploration industry since the 1960s and have improved significantly in the last two decades. These tools can provide estimates of bulk porosity and fluid content, quantification of bound versus mobile fluids, and estimates of hydraulic conductivity (K). Although the size and cost of oil‐field tools historically limited their use for near‐surface applications, smaller and more economical downhole NMR logging tools are now available for detecting and characterizing the formation water content and K to support environmental and groundwater resource investigations. These tools can be deployed using direct‐push drilling techniques or they can be lowered into existing open borings or wells with nonconductive polyvinyl chloride casings and screens. In many cases, using the tool in existing wells offers a safer and more cost‐effective alternative compared to drilling new boreholes. For environmental investigations, NMR can provide useful high‐resolution quantitative hydrostratigraphic information that can provide additional valuable data to further inform and refine the conceptual site model. This paper highlights several NMR field investigations that demonstrate the viability of this technology as a site characterization tool for near‐surface investigations. NMR measurements were compared to data from lithologic logs, cone penetrometer testing data, and prior field hydraulic tests. Use of NMR to detect vadose zone water, including previously unidentified perched groundwater zones, provided hydrostratigraphic details that could not be gleaned from historical well drilling logs and were used to evaluate drainable pore water versus pore water bound in small pores by capillary forces or electrochemically clay‐bond water. NMR also produced K estimates similar to those from conventional hydraulic tests, but the improved vertical resolution from NMR provided additional information regarding the vertical heterogeneity of the formation along the entire length of the well or borehole. Additionally, bench‐scale tests are presented that confirm the capability for NMR to reliably detect and quantify light nonaqueous phase liquid saturation (specifically diesel fuel and weathered gasoline) in situ. The field tests combined with bench‐scale testing results affirm the applicability and potential for NMR as a practical characterization tool that should increasingly be utilized in environmental investigations.
In situ chemical oxidation: Lessons learned at multiple sites
Authors: Pac Timothy J. , Baldock James , Brodie Brendan , Byrd Jennifer , Gil Beatriz , Morris Kevin A. , Nelson Denice , Parikh Jaydeep , Santos Paulo , Singer Miguel , Thomas Alan 
Published: March 2019

AbstractThis paper compiles a detailed set of in situ chemical oxidation (ISCO) lessons learned pertaining to design, execution, and safety based on global experiences over the last 20 years. While the benefits of a “correct” application are known (e.g., cost effectiveness, speed, permanence of treatment), history also provides examples of a variety of “incorrect” applications. These provide an opportunity to highlight recurring themes that resulted in failures. ISCO is, and will continue to provide, an important remedial tool for site remediation, particularly as a component of a multifaceted approach for addressing large and complex sites. Future success, however, requires an objective understanding of both the benefits and the limitations of the technology. The ability to learn from the mistakes of the past provides an opportunity to eliminate, or at least minimize, them in the future. Over the last 25 years of ISCO application, process understanding and knowledge have improved and evolved. This paper combines a thorough discussion of lessons learned through decades of ISCO implementation throughout all aspects of ISCO projects with an analysis of changes to the ISCO remediation market. By discussing the interplay of these two themes and providing recommendations from collective lessons learned, we hope to improve the future of safe, cost‐effective, and successful applications of ISCO.
Evaluating the longevity of a PFAS in situ colloidal activated carbon remedy
Authors: Carey Grant R. , McGregor Rick , Pham Anh Le‐Tuan , Sleep Brent , Hakimabadi Seyfollah Gilak 
Published: March 2019

AbstractThe remediation of per‐ and polyfluoroalkyl substances by injection of colloidal activated carbon (CAC) at a contaminated site in Central Canada was evaluated using various visualization and modeling methods. Radial diagrams were used to illustrate spatial and temporal trends in perfluoroalkyl acid (PFAA) concentrations, as well as various redox indicators. To assess the CAC adsorption capacity for perfluorooctane sulfonate (PFOS), laboratory Freundlich isotherms were derived for PFOS mixed with CAC in two solutions: (1) PFOS in a pH 7.5 synthetic water that was buffered by 1 millimolar NaHCO3 (Kf = 142,800 mg1‐a La/kg and a = 0.59); and (2) a groundwater sample (pH = 7.4) containing PFOS among other PFAS from a former fire‐training area in the United States (Kf = 4,900 mg1‐a La/kg and a = 0.24). A mass balance approach was derived to facilitate the numerical modeling of mass redistribution after CAC injection, when mass transitions from a two‐phase system (aqueous and sorbed to organic matter) to a three‐phase system that also includes mass sorbed to CAC. An equilibrium mixing model of mass accumulation over time was developed using a finite‐difference solution and was verified by intermodel comparison for prediction of CAC longevity in the center of a source area. A three‐dimensional reactive transport model (ISR‐MT3DMS) was used to indicate that the CAC remedy implemented at the site is likely to be effective for PFOS remediation for decades. Model results are used to recommend remedial design and monitoring alternatives that account for the uncertainty in long‐term performance predictions.
Multifunctional Ternary Nanocomposites of Ni/Polypyrrole/Reduced Graphene Oxide as Supercapacitor and Electrocatalyst in Methanol Oxidation
Authors: Sarkar Chandrama , Nath Jayashree , Bhuyan Shilpa , Dolui Swapan K. 
Published: March 2019

AbstractIn this work the concurrent electrochemical energy storage and conversion characteristics of Ni nanoparticles supported on polypyrrole‐reduced graphene oxide (Ni/PPy/rGO) nanocomposite is reported. Ni/PPy/rGO nanocomposite was synthesized by mixing its precursors PPy/rGO and NiCl2.6H2O, where Ni2+ was reduced to Ni at pH 10.5. The obtained nanocomposite is characterized using FTIR, XRD, Raman Spectroscopy, SEM and dynamic light scattering methods. The electrochemical energy storage properties of the nanocomposite are investigated using cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy tests. Electrochemical analysis reveals that Ni/PPy/rGO nanocomposite has high specific capacitance of 763.49 Fg−1 at 1.31 Ag−1 current density with capacity retention of 96.75% after 200 cycles Ni/PPy/rGO nanocomposite is also used as electrode in methanol electro‐oxidation. Cyclic voltammetry and chronoamperometry are carried out to study the electrochemical energy conversion properties of the composite towards methanol electro‐oxidation. The anodic current density of the Ni/PPy/rGO nanocomposite is much higher than that of Ni/rGO and PPy/rGO. Moreover, the onset potential of Ni/PPy/rGO nanocomposite is much lower than that of Ni/rGO and PPy/rGO. The results show that the Ni/PPy/rGO nanocomposite is electro‐catalytically active and highly stable.
Single and Binary Adsorption of Zn (II) and Cr (VI) Heavy Metals onto Synthesized Silica ‐Based MCM‐41
Authors: Toor Sehaspreet Kaur , Kushwaha Jai Prakash , Sangal Vikas Kumar 
Published: March 2019

AbstractEffluents from numerous Industries like textile, paint, pharmaceutical, steel and electroplating industries liberate both Zinc [Zn (II)] and Chromium [Cr (VI)] heavy metals. In this work, adsorptive interaction of toxic Zn (II) heavy metal in aqueous solution with synthesized mesoporous silica based MCM‐41 was investigated. Further, the effects of presence of Cr (VI) heavy metal on the adsorption of Zn (II) and vice versa were investigated by simultaneous competitive binary adsorption from Cr (VI) and Zn (II) aqueous binary solution. Batch experiments were executed to see the effects of parameters like pH, adsorbent dose (m), adsorbate concentration and adsorption time (t). Optimum conditions for Zn (II) treatment were obtained as: initial pH (pHi) =7, m=0.1 g/L and t=2 h. Competitive adsorption of both Cr (VI) and Zn (II) from their binary solution was studied at 288− 308 K temperatures. Obtained equilibrium data were then fitted to different competitive multicomponent isotherm models like Langmuir (extended), Freundlich isotherm (extended), Sheindrof‐Rebuhn‐Sheintuch (SRS) isotherm and Redlich‐Peterson isotherm (modified) models, and various isotherm interaction parameters were calculated.
Aza‐Michael Addition of 5‐Substituted Tetrazole Catalysed By a Novel Nanoparticle Solid Base Catalyst Involving a Layered Zinc Hydroxide Supported on a Ferrite Core
Authors: Pazoki Farzane , Mehraban Jamshid Azarnia , Shamsayei Maryam , Bakhshi Bita , Esfandiarpour Razieh , Miraki Maryam Kazemi , Heydari Akbar 
Published: March 2019

AbstractFe3O4@SiO2@layered Zinc hydroxide (LZH) (0.85 mol %) efficiently was catalyzed the aza‐Michael reaction of 5‐substituted tetrazoles derivatives with α, β‐unsaturated carbonyl compound under reflux in acetonitrile to produce the new compounds. These new compounds were investigated for antibacterial activity and studied for the structural properties by theoretical calculations.
An Anthracene Excimer Fluorescence Probe on Mesoporous Silica for Dual Functions of Detection and Adsorption of Mercury (II) and Copper (II) with Biological In Vivo Applications
Authors: Chatterjee Sobhan , Gohil Hardipsinh , Raval Ishan , Chatterjee Shruti , Paital Alok Ranjan 
Published: March 2019

AbstractDual functional activity by the same organic–inorganic hybrid material toward selective metal ion detection and its adsorption has drawn more attraction in the field of sensing. However, most of the hybrid materials in the literature are either for sensing studies or adsorption studies. In this manuscript, a fluorescent active hybrid material SiO2@PBATPA is synthesized by covalent coupling of anthracene‐based chelating ligand N,N′‐(propane‐1,3‐diyl) bis(N‐(anthracen‐9‐ylmethyl)‐2‐((3‐(triethoxysilyl)propyl) amino) acetamide) (PBATPA) within the mesopores of newly synthesized cubic mesoporous silica. The synthetic strategy is designed to form an exclusively intramolecular excimer on a solid surface, which is then used as a sensory tool for selective detection of metal ions through fluorescence quenching by the destruction of excimer upon metal ion binding. The dual functions of sensing and adsorption studies show selectivity toward Hg2+ and Cu2+ among various metal ions with detection limits of 37 and 6 ppb, respectively, and adsorption capacities of 482 and 246 mg g−1, respectively. This material can be used as a sensory cum adsorbent material in real food samples and living organisms such as the brine shrimp Artemia salina without any toxic effects from the material.
Silica‐Mediated Formation of Nickel Sulfide Nanosheets on CNT Films for Versatile Energy Storage
Authors: Lu Pengyi , Wang Xiaowei , Wen Lei , Jiang Xiaotong , Guo Wenlei , Wang Lei , Yan Xiao , Hou Feng , Liang Ji , Cheng Hui‐Ming , Dou Shi Xue 
Published: March 2019

AbstractAn effective, nondestructive, and universal strategy to homogeneously modify freestanding carbon nanotube (CNT) films with various active species is essential to achieve functional electrodes for flexible electrochemical energy storage, which is challenging and has attracted considerable research interest. In this work, a generalizable concept, to utilize silicon oxide as the intermediate to uniformly decorate various metal sulfide nanostructures throughout CNT films is reported. Taking nickel sulfide nanosheet/CNT (NS/CNT) films, in which the NS nanosheets are homogeneously attached on the intact few‐walled CNTs, as an example, the sheet‐like NS provides sufficient active sites for redox reactions and the CNT network acts as an efficient electron highway, maintaining the structural integrity of the composite and also buffering volume changes. These merits enable NS/CNT films to meet the requirements of versatile energy storage applications. When used for supercapacitors, a high specific capacitance (2699.7 F g−1/10 A g−1), outstanding rate performance at extremely high rates (1527 F g−1/250 A g−1), remarkable cycling stability, and excellent flexibility can be achieved, among the best performance so far. Moreover, it also delivers excellent performance in the storage of Li and Na ions, meaning it is also potentially suitable for Li/Na ion batteries.
A Directional Strain Sensor Based on Anisotropic Microhoneycomb Cellulose Nanofiber‐Carbon Nanotube Hybrid Aerogels Prepared by Unidirectional Freeze Drying
Authors: Wang Cong , Pan Zheng‐Ze , Lv Wei , Liu Bilu , Wei Jie , Lv Xiaohui , Luo Yi , Nishihara Hirotomo , Yang Quan‐Hong 
Published: March 2019

AbstractAerogels are one of the most popular composite reinforcement materials because of their high porosity and their continuous and homogeneous network. Most aerogels are isotropic, thus leading to isotropic composites when they are used as fillers. This fundamentally limits their applications in areas where anisotropy is needed. Here, an anisotropic microhoneycomb cellulose nanofiber‐ (CellF)‐carbon nanotube (CNT) aerogel (denoted MCCA) is reported that contains unidirectionally aligned penetrating microchannels, which is prepared by a unidirectional freeze‐drying method, using the structure‐directing function of the CellFs. Due to its anisotropic nature, MCCA‐reinforced polydimethylsilexane (denoted MCCA/PDMS) shows distinct anisotropic behavior, with the electrical conductivity and Young's modulus along the direction of penetrating microchannels being approximately twice those in the orthogonal direction. MCCA/PDMS is used to make “directional” strain sensors with electrical resistance as the output signal. They demonstrate a 92% sensitivity difference between the microchannel direction and its orthogonal direction. This approach can be used to prepare anisotropic MCCA‐based composites with other polymers for different applications.
Intelligent sentiment analysis approach using edge computing‐based deep learning technique
Authors: Sankar H. , Subramaniyaswamy V. , Vijayakumar V. , Arun Kumar Sangaiah , Logesh R. , Umamakeswari A. 
Published: March 2019

SummarySentiment analysis and opinion mining has become a major tool for collecting information from customer reviews on user sentiments and emotions, especially for online video streaming services and social networks. The increasing use of smartphones has popularized subscription to various streaming services that provide streaming media and video‐on‐demand. These applications offer a gateway to analyze user reviews by introducing sentiment analysis in the mobile environment. Online user reviews can hold a lot of useful information and help predict user interests. Analysis of user reviews can provide substantive information for business processing. Sentiment classification of these reviews is a commonly used analysis technique. Usually, these reviews are given in a text format, with every word in each considered a feature, so selection should focus on optimal features from all available features present in the reviews. This study employs machine learning algorithms to extract the best features from the training review data set. Then, the selected features are fed into the convolutional neural network and other fully connected layers for further processing. The proposed approach is evaluated with the standard evaluation metrics, such as precision, accuracy, recall, and f‐measure, using three distinct benchmark data sets: polarity, Rotten Tomatoes, and IMDb. This work has also employed a pretrained sentiment analysis model over an Android application framework to classify reviews on a Smartphone without the need for any cloud or server‐side API.
Model‐based protocol specification
Authors: Mordecai Yaniv 
Published: March 2019

AbstractWe propose a holistic Model‐Based Protocol Specification (MBPS) framework. Standards, procedures, and protocols are important anchors for interconnected systems: they facilitate the connectivity of billions of devices around the world, commodify advanced technologies and solutions, and enable efficient services involving trillions of transactions in aviation, medicine, e‐commerce, transportation, infrastructure, and other domains. Domain protocols allow for conventional interactions within a domain among ecosystem entities and humans (eg, airline ticketing, financial transactions, etc). Protocol specifications must be formal, consistent, and verifiable. Nevertheless, most current standard protocols are text‐based, unverifiable, and often inconsistent with themselves and with other standards. Text‐based standards are difficult to manage, track, control, and adopt. MBPS includes three critical enablers: a modeling language, a modeling process, and a model‐supported standardization process. This paper employs Object‐Process Methodology (OPM), a model‐based systems engineering framework, endorsed as ISO‐19450, for modeling and simulation of the generic protocol specification process and for two examples: (a) a Kerberos authentication protocol revision based on a previous Kerberos model and on a recently discovered vulnerability and (b) a domain‐specific Publish—Subscribe protocol application for selective information distribution.
Catalytic Asymmetric Synthesis of Spiropyrazolones and their Application in Medicinal Chemistry
Authors: Xie Xin , Xiang Li , Peng Cheng , Han Bo 
Published: March 2019

AbstractChiral spiropyrazolones are unique frameworks widely found in a large family of medicinally relevant compounds with various biological activities. Substantial research efforts have been invested toward stereoselectively by constructing spiro‐cyclic structures. Over the past years, remarkable progress has been made in the organo‐ and metal‐catalyzed asymmetric synthesis of spiropyrazolones through the utilization of accessible simple pyrazolone derivatives as raw materials. This review is organized according to the size of the spiro‐ring fused at the 4‐position of the pyrazolone framework. In the last part, the bio‐evaluations of chiral spiropyrazolones for drug discovery are summarized.
The SMFA program for quantum chemistry calculations on large molecules
Authors: Kobayashi Rika , Addicoat Matthew A. , Gilbert Andrew T.B. , Amos Roger D. , Collins Michael A. 
Published: March 2019

SMFA is a general program package for performing quantum chemistry calculations on large molecules, using an energy‐based fragmentation approach. The program can calculate electronic energies, energy gradients and second derivatives; perform geometry optimization; find first order saddle points (transition states); perform energy optimized scans along a user‐defined path; and evaluate various molecular properties. The program can use any of the following quantum chemistry packages: GAMESS(US), GAUSSIAN, NWChem and Q‐Chem. In addition, SMFA provides a number of utility programs that,inter alia, calculate vibrational frequencies and infrared spectra with isotopic substitutions, the electrostatic potential on the solvent‐accessible‐surface, and isodesmic and higher order near‐iso‐energetic reaction schemes. Calculations of the electronic energy and related properties can be carried out using a scheme that provides a computation time that is linearly dependent on the size of the molecule or, if the user has enough processing units available, in a walltime that is independent of the size of the molecule.This article is categorized under:Software > Quantum ChemistryElectronic Structure Theory > Ab Initio Electronic Structure MethodsStructure and Mechanism > Computational Biochemistry and Biophysics
From modelling of systems with constraints to generalized geometry and back to numerics
Authors: Salnikov Vladimir , Hamdouni Aziz 
Published: March 2019

AbstractIn this note we describe how some objects from generalized geometry appear in the qualitative analysis and numerical simulation of mechanical systems. In particular we discuss double vector bundles and Dirac structures. It turns out that those objects can be naturally associated to systems with constraints – we recall the mathematical construction in the context of so called implicit Lagrangian systems. We explain how they can be used to produce new numerical methods, that we call Dirac integrators.On a test example of a simple pendulum in a gravity field we compare the Dirac integrators with classical explicit and implicit methods, we pay special attention to conservation of constrains. Then, on a more advanced example of the Ziegler‐type system we show that the choice of numerical methods can indeed affect the conclusions of qualitative analysis of the dynamics of mechanical systems. We also tell why we think that Dirac integrators are appropriate for this kind of systems by explaining the relation with the notions of geometric degree of non‐conservativity and kinematic structural stability.