An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
chemicalanalysis, etc ; economic analysis; electricity; equipment; exergy; heat transfer; hydrogen bonding; quantum mechanics; steam; temperature; Show all 10 Subjects
Abstract:
... A screening strategy was established for obtaining an optimal working fluid (R1234yf) based on quantum chemical analysis. The weak hydrogen bond interactions of R1234yf enhanced the performance of the organic Rankine cycle. The proposed process produced 49.28 MW of electricity and 0.5 MPa of steam. The optimal process was evaluated by multifactor analysis of exergy, economic, and exergoenvironment ...
chemicalanalysis, etc ; X-ray fluorescence spectroscopy; calibration; clay; detection limit; energy-dispersive X-ray analysis; Show all 6 Subjects
Abstract:
... In this paper, the main subject concerns comparing different techniques to prepare raw clay samples for energy-dispersive X-ray fluorescence spectrometry (EDXRF). Three kinds of sample preparation procedures are examined, such as loose powder, pressed pellet, and fired pressed pellet. The fired pressed pellet approach was observed as a part of universal sample preparation for physic, mechanical, a ...
... Many environmental contaminants could be transmitted from parents and generate impairments to their progeny. The 2,4,6-tribromophenol (TBP), a novel brominated flame retardant which has been frequently detected in various organisms, was supposed to be bioaccumulated and intergenerational transmitted in human beings. Previous studies revealed that TBP could disrupt thyroid endocrine system in zebra ...
chemicalanalysis, etc ; Hermetia illucens; Simuliidae; chemometrics; feeds; food safety; least squares; markets; model validation; prediction; principal component analysis; protein content; support vector machines; Show all 13 Subjects
Abstract:
... The production of alternative proteins to meet the demand of a growing population has accelerated the growth of the market for edible insects. Black fly soldier (BFS) larvae (Hermetia illucens L.) have been widely studied globally due to their high content of fat, protein, and minerals, being mainly used for animal feed. Chemical analysis for determination of its composition is time consuming and ...
... Tractors are used for various types of field work, as well as for transport on public roads, in difficult and changing environmental conditions. The main goal of the study was to analyze the changes of trace elements in engine oil during various field works. For this purpose, engine oils from two tractors were selected for the study. These tractors were coupled with: a cultivator, a reversible plo ...
chemicalanalysis, etc ; deformation; transmission electron microscopy; Show all 3 Subjects
Abstract:
... Advances in the use of in situ transmission electron microscopy (TEM) to study mechanical deformation have enabled a direct correlation of mechanical properties with microstructures, in particular, atomic-level defect dynamic processes. Shear deformation of metallic materials has been noticed to lead to unique microstructural features with superior properties that would be difficult to achieve by ...
chemicalanalysis, etc ; acrolein; electronic equipment; nicotine; Show all 4 Subjects
Abstract:
... Signal amplification by reversible exchange (SABRE) hyperpolarisation is used to enhance the NMR signals of nicotine and acrolein in methanol-d₄ solutions of electronic cigarette aerosols. Consequently, detection of 74 μM nicotine is possible in just a single scan ¹H NMR spectrum. The first example of an aldehyde hyperpolarised using SABRE is demonstrated and we work towards novel real-world appli ...
chemicalanalysis, etc ; chemical species; fluorescence; medicine; toxicity; Show all 5 Subjects
Abstract:
... Luminescent quantum dots (QDs) of I–III–VI₂ semiconductors present a new class of luminescence materials that combine unique optical and electronic properties while exhibiting low toxicity compared to conventional cadmium-based QDs. Advances in the colloidal synthesis of ternary QDs have been used to develop fluorescence chemical and biological sensors for the detection of various analytes. The re ...
chemicalanalysis, etc ; chemical bonding; chemical communication; exhibitions; spectroscopy; Show all 5 Subjects
Abstract:
... Photoelectron spectroscopy and quantum chemistry studies are used to investigate the structure and bonding of AuB₈⁻. Global minimum sturctural searches show that AuB₈⁻ possesses a chair-like structure, which can be viewed as Au⁺ bonded to the edge of the doubly-aromatic B₈²⁻ borozene, Au⁺[η²-B₈²⁻]. Chemical bonding analyses reveal that the AuB₈⁻ is a novel borozene complex with unique Au–borozene ...
chemicalanalysis, etc ; fiberglass; latex; microparticles; polystyrenes; polytetrafluoroethylene; topography; Show all 7 Subjects
Abstract:
... Improvement of the particle collection efficiency of sampling wipes is desirable for optimizing the performance of many wipe-based chemical analysis techniques used for trace chemical screening applications. In this note, commercially available Teflon coated fiberglass and calendered Nomex sampling wipes were modified by mechanically scoring the wipe surface to produce topography that promoted enh ...
chemicalanalysis, etc ; air; foams; polyurethanes; Africa; Asia; Caribbean; Show all 7 Subjects
Abstract:
... As part of the global monitoring plan on persistent organic pollutants (GMP) under the Stockholm Convention passive air samplers equipped with polyurethane foam disks (PUFs) were applied to monitor dioxin-like POPs. For sampling, toluene-pretreated PUFs were exposed for three months during two years. Chemical analysis was performed in one accredited expert laboratory using internationally accepted ...
chemicalanalysis, etc ; databases; marine environment; sediments; soil; traceability; Show all 6 Subjects
Abstract:
... Traceability and reliable results are the two pillars of analytical methods; certified reference materials (CRMs) meet this requirement. ISO 17034:2016 credentials provide brief information on general requirements for the competence of Reference Material Producers (RMPs). The different types of CRMs have been produced in recent years for chemical analysis in food, water, soil, and sediment matrice ...
chemicalanalysis, etc ; isotropy; nuclear magnetic resonance spectroscopy; quantum mechanics; Show all 4 Subjects
Abstract:
... Chemical analysis based on liquid-state nuclear magnetic resonance spectroscopy exploits numerous observables, mainly chemical shifts, relaxation rates, and internuclear coupling constants. Regarding the latter, the efficiencies of internuclear coherence transfers may be encoded in spectral peak intensities. The dependencies of these intensities on the experimental parameter that influences the tr ...
chemicalanalysis, etc ; Olea europaea; antioxidants; cytotoxicity; food additives; research; therapeutics; Show all 7 Subjects
Abstract:
... The Olea europaea L. is a very well-known and widely used plant, especially for its nutritional qualities. Its extracts from leaves and fruits are widely used in contrasting and preventing various pathologies. In this review, the collected data highlight important chemical analyses and biological effects of this plant extracts. It exhibits cholesterol-lowering, hypoglycemic, cytotoxic, antibacteri ...
chemicalanalysis, etc ; adsorption; chemical species; coordination polymers; detection limit; rhodamines; Show all 6 Subjects
Abstract:
... In the surface-enhanced Raman scattering (SERS) measurements, it is very important to fabricate “hot spots” and concentrate the analytes into these regions. In this work, a hybrid structure of Au nanostars (NSs) with high SERS sensitivity and metal-organic framework MIL-101(Fe) with high molecular adsorption capability was constructed as high performance SERS substrate. The MIL-101(Fe) shell betwe ...
chemicalanalysis, etc ; aerosols; environment; fluorenes; particulates; toxicity; urban areas; Germany; Show all 8 Subjects
Abstract:
... Using a multidisciplinary approach, this study provides insight into everyday exposure scenarios of urban commuters to aerosol particles and their associated polycyclic aromatic hydrocarbons. It combines high spatiotemporal resolution particle measurements, used to determine the distribution of particulate matter in the urban environment, with the chemical analysis of the health-relevant particle ...
chemicalanalysis, etc ; Hydrangea macrophylla; cultivars; quality control; research and development; Show all 5 Subjects
Abstract:
... Hyperspectral data are commonly used for the fast and inexpensive quantification of plant constituent estimation and quality control as well as in research and development applications. Based on chemical analysis, different models for dihydroisocoumarins (DHCs), namely hydrangenol (HG) and phyllodulcin (PD), were built using a partial least squares regression (PLSR). While HG is common in Hydrange ...
chemicalanalysis, etc ; cameras; data collection; lipid content; models; prediction; salmon; wavelengths; Show all 8 Subjects
Abstract:
... Portable hyperspectral Imaging (HSI) based on snapshot sensors is ideal for on-line applications, with very fast data acquisition, small camera and flexibility for implementation. The objective of the study was to assess a snapshot HSI system for on-line assessment of salmon by bench marking it against a conventional hyperspectral system. Two different HSI systems: (a) linescan (550–1700 nm) and ( ...
chemicalanalysis, etc ; databases; fertigation; industry; leaves; soil; sugarcane; sugars; vinasse; Brazil; Show all 10 Subjects
Abstract:
... This study aimed to determine DRIS standards and indices in commercial sugarcane plantations through soil, leaf, and stem samples collected in the southern region of the state of Goiás, Brazil. The experiment was arranged in a 2 × 2 factorial design with two cultivation systems (with or without vinasse application) and two sugarcane varieties (CTC 4 and RB 867515), both with 50 sampling points. Th ...
Maria Verde; Alberto De Bonis; Francesco D'Uva; Vincenza Guarino; Francesco Izzo; Concetta Rispoli; Giovanni Borriello; Marco Giglio; Stefano Iavarone; Vincenzo Morra
chemicalanalysis, etc ; archaeology; ceramics; clay; kilns; polarized light microscopy; provenance; Italy; Show all 8 Subjects
Abstract:
... The focus of this work is the archaeometric investigation of ceramic wasters found in a dump in the workshop area of Cumae that are mostly represented by important production indicators of pottery produced in the Augustean-Tiberian period. The fragments belong to different ceramic classes and productions, such as: pompeian red ware, common cookwares, parts of kiln vault, thin-walled pottery, terra ...