Quantitative Analysis Of Products Research Articles

Design of an optofluidic diffusion sensor by transient grating using dielectrophoresis.

An optofluidic diffusion sensor using laser-induced dielectrophoresis in a device with a sputtered a-Si:H layer is presented. Diffusion sensors enabling high-speed measurement have important potential uses as bio-sensors and for quantitative analysis of nano-sized products. The present sensor was developed for measurement in a few seconds by optic observations of the sample diffusion from transient grating formed by laser-induced dielectrophoresis. As a photoconductive layer for the proposed device, we used a sputtered a-Si:H film. The optical (refractive index and extinction coefficient), structural (Raman and IR spectroscopy), and optoelectronic properties of this film, as well as its applicability to the proposed device are characterized. Nano-sized beads were measured by the fabricated device, and its performance as a diffusion sensor was validated.

Quantification of protein in wheat using near infrared hyperspectral imaging: Performance comparison with conventional near infrared spectroscopy

Hyperspectral imaging is a powerful technique that combines the advantages of near infrared spectroscopy and imaging technologies. Most hyperspectral imaging studies focus on qualitative analysis, but there is growing interest in using such technique for the quantitative analysis of agro-food products in order to use them as universal tools. The overall objective of this study was to compare the performance of a hyperspectral imaging instrument with a classical near infrared instrument for predicting chemical composition. The determination of the protein content of wheat flour was selected as example. Spectra acquisition was made in individual sealed cells using two classical near infrared instruments (NIR-DS and NIR-Perstop) and a near infrared hyperspectral line-scan camera (NIR-HSI). In the latter, they were also acquired in open cells in order to study the possibility of accelerating the measurement process. Calibration models were developed using partial least squares for the full wavelength range of each individual instrument and for the common range between instruments (1120–2424 nm). The partial least squares models were validated using the “leave-one-out” cross-validation procedure and an independent validation set. The results showed that the NIR-HSI system worked as well as the classical near infrared spectrometers when a common wavelength range was used, with an r2 of 0.99 for all instruments and Root Mean Square Error in Prediction (RMSEP) values of 0.15% for NIR-HSI and NIR-DS and 0.16% for NIR-Perstop. The high residual predictive deviation values obtained (8.08 for NIR-DS, 7.92 for NIR-HSI, and 7.56 for NIR-Perstop) demonstrate the precision of the models built. In addition, the prediction performance with open cells was almost identical to that obtained with sealed cells.

Aluminum in Tobacco Products Available in the United States.

A quantitative method for the analysis of aluminum in tobacco products was developed, validated and applied to select samples. Samples were prepared using standard microwave digestion of tobacco from various products. Detection and quantification utilized sector field inductively coupled plasma-mass spectrometry. Method applicability to analyze aluminum in a range of tobacco products was demonstrated with quantitative analyses of smokeless tobacco products, cigarette tobacco, little cigar tobacco and roll-your-own/pipe tobacco. Though these products represent a convenience sampling, we observed that smokeless tobacco products, as a category, had the lowest average aluminum concentrations. Roll-your-own or pipe tobacco and little cigar tobacco had higher median and ranges of aluminum concentrations than cigarette and smokeless tobacco samples.

A temperature-controlled photoelectrochemical cell for quantitative product analysis.

In this study, we describe the design and operation of a temperature-controlled photoelectrochemical cell for analysis of gaseous and liquid products formed at an illuminated working electrode. This cell is specifically designed to quantitatively analyze photoelectrochemical processes that yield multiple gas and liquid products at low current densities and exhibit limiting reactant concentrations that prevent these processes from being studied in traditional single chamber electrolytic cells. The geometry of the cell presented in this paper enables front-illumination of the photoelectrode and maximizes the electrode surface area to electrolyte volume ratio to increase liquid product concentration and hence enhances ex situ spectroscopic sensitivity toward them. Gas is bubbled through the electrolyte in the working electrode chamber during operation to maintain a saturated reactant concentration and to continuously mix the electrolyte. Gaseous products are detected by an in-line gas chromatograph, and liquid products are analyzed ex situ by nuclear magnetic resonance. Cell performance was validated by examining carbon dioxide reduction on a silver foil electrode, showing comparable results both to those reported in the literature and identical experiments performed in a standard parallel-electrode electrochemical cell. To demonstrate a photoelectrochemical application of the cell, CO2 reduction experiments were carried out on a plasmonic nanostructured silver photocathode and showed different product distributions under dark and illuminated conditions.

Rapid Determination of Two Triterpenoid Acids in Chaenomelis Fructus Using Supercritical Fluid Extraction On-line Coupled with Supercritical Fluid Chromatography.

In this study, an on-line supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) method was developed for the rapid determination of oleanoic acid and ursolic acid in Chaenomelis Fructus. After optimization of the conditions, the two triterpenoid acids was obtained by SFE using 20% methanol as a modifier at 35°C in 8 min. They were resolved on a Shim-pack UC-X Diol column (4.6 × 150 mm, 3 μm) in 14 min (0 - 10 min, 5 - 10%; 10 - 14 min, 10% methanol in CO2) with a backpressure of 15 MPa at 40°C. The on-line SFE-SFC method could be completed within 40 min (10.79 mg/g dry plant, Rs = 2.36), while the ultrasound-assisted extraction and HPLC method required at least 90 min (3.55 mg/g dry plant, Rs = 1.92). This on-line SFE-SFC method is powerful to simplify the pre-processing and quantitative analysis of natural products.

Enhanced heat stable antifungal factor production by Lysobacter enzymogenes OH11 with cheap feedstocks: medium optimization and quantitative determination.

Significance and Impact of the Study: Heat stable antifungal factor (HSAF) exhibits a potent and broad antifungal activity with a novel mode of action. Increased production and reduced cost of raw materials are particularly important for the future production of HSAF, however, no report was involved in these studies. This study aimed to improve the production of HSAF with cheap raw materials through the medium optimization, which would lay the foundation for the application of HSAF in biological control.

A Mapping Review of Poster Presentation Publications Across Time and Academic Disciplines

A Review of: Rowe, N. (2017). Tracing the 'grey literature' of poster presentations: A mapping review. Health Information & Libraries Journal, 34(2), 106-124.
 Abstract
 Objective – To map the development and use of poster presentations in order to determine disciplines in which they are particularly prolific and how their popularity or presence may have changed over time. This will potentially assist health and interdisciplinary librarians asked to search for poster presentations in systematic reviews.
 Design – Informetric mapping review.
 Setting – An unnamed UK University Library search facility which processes 249 international databases and research publications. Databases and publications range across 37 research disciplines, including literature, medicine, and engineering.
 Subjects – Published literature connected to poster presentations – the authors state that this could be poster presentations themselves, abstracts, title listings in conference proceedings, or any variety of materials. They also state that over 99% of the results of this review were title citations or abstracts of conference poster presentations.
 Methods – An informetric mapping review was conducted via a UK University Library search facility by searching for the term “poster presentation” in 249 databases spanning 37 research areas. An index of databases used is provided as an appendix to the article. Results were not connected by the search facility to an individual database. Search results were categorized by discipline and decade of publication. Scholarly and peer-reviewed search limiters were used to obtain an idea of the themes and contributions to what could be considered core literature, and the search was also run in Google Scholar to provide a comparator. Duplications across databases were removed by the search service, although several results appeared both in aggregate (for example, conference proceedings encompassing all poster presentations) and individual form. Review of results took an informetrics approach, concerned with quantitative analysis (number of publications over time, number of publications in specific areas or by certain authors, etc.) of production, publication, and use of information, and not with its origins or quality.
 Main Results – Even with limiters for peer reviewed or scholarly sources applied, over 99% of returns were abstract or title citations for conference poster presentations – sources which by themselves may not meet the requirements for being scholarly information. From 1937-1969, results only uncovered references to poster use in an educational context. From 1970-1979, the researchers found that poster presentations became a common conference feature, although a less prestigious one than papers. 1980-1989 reiterated the commonality of academic posters, and saw publication of works to advise poster preparation and running poster sessions. During the years 1990-1999, health related disciplines became the main users of posters as an academic medium with 68% of search returns being in health care disciplines. The prominence of posters in health and medicine increased over time. From 2000-2009, search returns in this study show an increase of 360% from those located in 1990-1999. This could indicate an increase in poster sessions, an increase in search accuracy and online availability of material, or both. Health care and medical disciplines have demonstrated the most prominent use of poster sessions since the 1990s, although all disciplines have visible poster presentation activity.
 Conclusions – The author concludes that consistently increasing levels of return for poster abstracts indicate that poster presentations are a fulfilling and popular activity that will continue to be practiced by academics worldwide, but that literature in this review raises issues with the effectiveness of posters as ways to disseminate and discuss research. Locating and acquiring conference poster content, not just abstracts or titles, has been a recognized issue in libraries for many years. The authors conclude that the increasing number of poster presentations over time makes it more urgent that we determine what the personal and objective needs of poster users are and ensure that we are meeting them.

Application of sequential extraction analysis to Pb(II) recovery by zerovalent iron-based particles

Zerovalent iron (ZVI) is an environmental-friendly reactive reagent for recovering heavy metals. However, the detailed recovery mechanism remains unclear due to a lack of quantitative analysis of recovery products. Herein, microscale ZVI, nanoscale ZVI and Ni/Fe nanoparticles were used to recover Pb(II) in aqueous solution and a sequential extraction procedure (SEP) was applied to determine the formed lead species quantitatively. At high initial Pb(II) concentration (500 mg L−1), more than 99.5% of Pb(II) was immobilized by Ni/Fe and n-ZVI, whereas m-ZVI caused inferior recovery efficiency (<25%). XRD and XPS results revealed that Pb(II) was reduced to Pb0 prior to the formation of metal hydroxides as the external shell of ZVI. SEP results showed that the fraction bound to carbonates (PbO), fraction bound to iron oxides and exchangeable fraction were the main lead species conducted by Ni/Fe, n-ZVI and m-ZVI, respectively. Consequently, (co-)precipitation and specific adsorption dominated Pb(II) recovery by Ni/Fe and n-ZVI, whereas m-ZVI conducted Pb(II) recovery mainly via weak adsorption. The reactivity of ZVI toward Pb(II) followed the increasing order of m-ZVI << n-ZVI ≤ Ni/Fe. The detailed mechanisms of Pb(II) recovery conducted by different ZVI were proposed.

Separation and Purification of Fructo-Oligosaccharide by High-Speed Counter-Current Chromatography Coupled with Precolumn Derivatization.

High-speed counter-current chromatography (HSCCC) coupled with precolumn derivatization was developed for isolating and purifying fructo-oligosaccharides (FOSs). Firstly, the total FOSs were precolumn derivatized and then separated by high-speed counter-current chromatography (HSCCC) with two-phase solvent system petroleum ether–n-butanol–methanol–water (3:2:1:4, v/v). Secondly, the obtained compounds were deacetylated and the fructo-oligosaccharides (FOSs) with high purity were obtained. Their structures were identified by mass spectrometry (MS) and nuclear magnetic resonance (NMR). This research successfully established a novel strategy for separation and purification of FOS. There is no doubt that the application of the research will be beneficial for the quantitative and qualitative analysis of products containing FOSs.

Main factors influencing the formation of thermogenic solid bitumen

Highly mature solid bitumen, a residue of oil cracking, is widespread in the lower Paleozoic paleo-oil reservoirs of southern China. Solid bitumen is not a simple, pure component, but rather a compositionally and structurally variable mixture of materials. This study investigated the formation of thermogenic solid bitumen and the effects of oil composition and reservoir environment. A series of seven gold-tube pyrolysis experiments were conducted: three used the main fraction groups (i.e., saturated, aromatic, and resin + asphaltene fractions) of crude oil to evaluate the effect of oil composition on the formation of solid bitumen during cracking; the other four tested the effects of water and pressure in reservoirs by simulating the cracking of crude oil under different reservoir conditions. Quantitative analyses of pyrolytic products (including methane, C2–C5 gaseous hydrocarbons, C6–C13 light hydrocarbons, C13+ heavy hydrocarbons, and solid bitumen) indicated that thermogenic solid bitumen formed at different stages of oil cracking, and its formation was clearly affected by oil composition. In contrast, water and pressure in the reservoir had little effect on the formation of solid bitumen.

Analytical Method Development Using Transmission Raman Spectroscopy for Pharmaceutical Assays and Compliance with Regulatory Guidelines—Part I: Transmission Raman Spectroscopy and Method Development

Transmission Raman spectroscopy is a relatively new technique for quantitative analysis of pharmaceutical products, either during manufacturing or as a finished product test. As with any new analytical tool, several things need to be accomplished for widespread application use—assessment of technical capability, fit with quality and manufacturing processes and successful deployment in a quality-controlled environment. The technical capability has been discussed previously, but the practicalities of method development and submission to regulatory authorities have not. In this, one of a series of two papers, the considerations for regulatory submission are discussed. In the second paper, practical method development will be presented and examples provided for data analysis and method development processes.

A bibliometric analysis of scientific production in lean supply

A lean supply chain arrangement should provide flow of goods, services and technology from the supplier of raw materials to the customer without waste. Lean supply is an increasingly visible area not only at the theoretical level, but also in terms of practical application in companies offering products or services. Thus, scientific progress in this field of study is fundamentally derived from the knowledge available about it, which is the result of investigations and interactions by researchers over time. The main objective of this study, therefore, is to conduct a quantitative analysis of scientific production on lean supply between 1992 and 2016. The work was carried out with a methodical review of the literature, relying on bibliometric techniques, by consulting the databases ISI Web of Knowledge and Scopus, and their treatment by Bibexcel and Pajek softwares. For the research, the term 'lean supply' was used as a key expression, generating a sample of 211 published articles. Descriptive statistical results were presented, identifying the authors, articles and journals most frequently referenced by scholars worldwide. At the end of the study, recent papers of the sample were classified and analysed based on research methods and industry sectors.

Quantitative analysis of products from lignin depolymerisation in high-temperature water

Different types of lignin have been depolymerized via oxidative cleavage in sub- and supercritical water. As expected, a wide range of products of different structure and molecular weight have been obtained. Instead of analysing them one by one, we believe that it is equally useful and much more feasible to determine certain global parameters such as type of aromatic substituents, OH functionality or molecular weight distribution, particularly if the objective is to obtain a mixture of compounds with a particular application. To this end, each sample (products of lignin depolymerisation) was fractionated according to its solubility in water and ethyl acetate and the yield of the different fractions was determined. Then each fraction was analysed using CHNS elemental analysis; 31P- and 13C NMR and aqueous Gel Permeation Chromatography (GPC). Important conclusions about the effect of the reaction on the lignin structure can be deduced. These conclusions agree with previous observations found in literature. Based on these conclusions, some further insights have been proposed.

Independent Generation and Reactivity of Thymidine Radical Cations.

Thymidine radical cation (1) is produced by ionizing radiation and has been invoked as an intermediate in electron transfer in DNA. Previous studies on its structure and reactivity have utilized thymidine as a precursor, which limits quantitative product analysis because thymidine is readily reformed from 1. In this investigation, radical cation 1 is independently generated via β-heterolysis of a pyrimidine radical generated photochemically from an aryl sulfide. Thymidine is the major product (33%) from 1 at pH 7.2. Diastereomeric mixtures of thymidine glycol and the corresponding 5-hydroxperoxides resulting from water trapping of 1 are formed. Significantly lower yields of products such as 5-formyl-2'-deoxyuridine that are ascribable to deprotonation from the C5-methyl group of 1 are observed. Independent generation of the N3-methyl analogue of 1 (NMe-1) produces considerably higher yields of products derived from water trapping, and these products are formed in much higher yields than those attributable to the C5-methyl group deprotonation in NMe-1. N3-Methyl-thymidine is, however, the major product and is produced in as high as 70% yield when the radical cation is produced in the presence of excess thiol. The effects of exogenous reagents on product distributions are consistent with the formation of diffusively free radical cations (1, NMe-1). This method should be compatible with producing radical cations at defined positions within DNA.

Methodological aspects of the quantitative texture analysis of HCP Alloy (Ti, Zr) sheet semiproducts

The specific features of the existing methods of quantitative texture analysis of semiproducts and products made of titanium and zirconium alloys are analyzed. A technique is proposed to determine the Kearns coefficients (f parameters) for sheets made of hcp-metal-based alloys with allowance for the weighting factor of each reflection in the standard stereographic triangle. The f parameters calculated for sheets made of a zirconium alloy and various titanium alloys using different techniques are compared. The accuracy of measuring the Kearns coefficients by the inverse pole figure method is estimated.

Study of the Process and Mechanism of the Remediation of Phenol Contaminated Soil by Plasma Vibrated Bed

Soil pollution is an important problem. The organic components of soil pollution are complex, and pose a significant threat to human health. In this work, a low-temperature plasma vibrated bed is applied to remediation of soil polluted by organics, with attention focused on phenol as a model pollutant. In the experiment, many factors of phenol degradation are studied and determined, such as discharge voltage, carrier gas, and soil moisture content. Increasing vibration frequency, decreasing electrode spacing, increasing voltage and a weakly alkaline soil are conducive to the degradation of pollutants. Air and oxygen give better degradation than nitrogen. The active particles generated in the discharge, such as ·OH, H2O2 and O3, are shown to play an important role in degradation of phenol. In addition, maleic acid and oxalic acid are found as intermediate product during the process of phenol degradation. Furthermore, according to the qualitative and quantitative analysis of phenol degradation products, the degradation mechanism diagram of phenol in soil is drawn up, which is instructive to improve the performance of the plasma vibrated bed in the future research.

Thermal cracking products and bio-oil production from microalgae Desmodesmus sp.

Qualitative and quantitative analyses of thermal cracking products from Desmodesmus sp. were performed based on pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) at different temperature regimes (350°C-750°C). After further analysis of a series of total ions chromatogram (TIC) and summarized, thermal cracking products of Desmodesmus sp. at different temperature regimes can be obtained, which mainly comprised of aliphatic hydrocarbons, nitrogen compounds, aromatic hydrocarbons, fatty acids, ketones, alcohols, aldehydes and furan compounds. Compared to bio-oil production at 650°C (32.07%), Desmodesmus sp. pyrolyzed at 750°C could produce the highest bio-oil content of 42.25%. However, higher temperature could lead to the formation of contaminants (nitrogen compounds and PAHs) more easily. Therefore, considering the higher content of bio-oil conversion and less pollutants generation, the optimum temperature for Desmodesmus sp. thermal cracking conversion was about 650°C. Keywords: microalgae, Desmodesmus sp., thermal cracking, bio-oil production, pyrolysis DOI: 10.25165/j.ijabe.20171004.3348 Citation: Li G, Xiang S N, Ji F, Zhou Y G, Huang Z G. Thermal cracking products and bio-oil production from microalgae Desmodesmus sp. Int J Agric & Biol Eng, 2017; 10(4): 198–206.

Water productivity and crop yield: A simplified remote sensing driven operational approach

This paper develops and proposes a simplified operational remote sensing approach to assist crop growth models in reproducing actual processes in the field by relating satellite based remote sensing data and key canopy biophysical parameters. While relationships between spectral vegetation indices (VI) and biomass production have been conducted in the past, we specifically pursue the relationship between crop transpiration and biomass production as described in the FAO-66 Aquacrop manual. The authors point to a possible general relationship between a transpiration coefficient (herein we propose the basal crop coefficient, Kcb, as a proxy) and biomass production. In parallel, many studies have demonstrated the well-established relationship between Kcb and remote sensing based VI. Thus, the relationship between both parameters has a strong basis but must be demonstrated. We analyze the relationship between biomass production and the reflectance based Kcb using field data obtained during 11 years in irrigated and rainfed soybeans and maize in eastern Nebraska. The analysis confirms that the relationship is strong and paves the way for the use of remote sensing data for a quantitative analysis of crop biomass production and yield.

Co-Electrolysis, Quo Vadis?

Co-electrolysis, the electrochemical conversion of steam and carbon dioxide with the use of renewably generated electricity to produce syngas, can be regarded as the enabling step to the sustainable production of synfuels and high-value chemicals. This advantageous method of beneficial CO2-valorization is predetermined to couple energy-intense sectors such as “traffic and transportation” and “chemical industry”. The needed products for these markets presuppose different syngas compositions through their production routes and according to that determine the applied technology of syngas generation by its achievable H2:CO ratio. The concept of high-temperature co-electrolysis offers both an efficient electrochemical conversion and accessibility to H2:CO distributions from 1:1 to 3:1 by a given set of parameters (temperature, current density, material,…). Though, this is yet to be shown as research has been focused on electrochemical analysis of materials, cells and stacks rather than on product distribution depending on operating parameters and an all-embracing quantitative product analysis[1]. Herein, we examine the possibilities and variety on syngas production with focus on (electrochemical) performance and syngas yield and composition under different conditions, e.g. temperature, current density, substrate composition. The experiments were executed on a cathode supported cell (CeramTec) composed of an LSCF anode, a CGO barrier-layer, an 8YSZ electrolyte and a Ni/8YSZ cathode. The testing took place in the temperature range of 750 to 900 °C with preset cell voltages up to 1.4 V. The ratios of water vapor to carbon dioxide have been set to 3:1, 2:1 and 1:1. Furthermore, the cells have been tested with a 50% water – 50% hydrogen mixture for comparison. I/V-measurements and electrochemical impedance spectroscopy have been conducted under the combinations of mentioned conditions. In addition, a full spectrum analysis of the product gases has been performed, i. e. water was not condensed from the product stream prior to the mass spectrometer. Current densities of up to over 1.7 A·cm-2 with polarization resistances of 24 mΩ·cm-2 have been obtained at 900 °C and a cell voltage of 1.4 V with a 9 nl·h-1 flow of 40% water, 40% CO2 and 20% H2 used. I/V-curves decrease in slope and increase in current density with increasing temperature (figure 1). Further investigation is ongoing and the electrochemical performance and efficiency of syngas production will be presented and discussed in detail. [1] S. Foit, I. C. Vinke, L. G. J. de Haart, R.-A. Eichel, Angewandte Chemie International Edition 2016, DOI: 10.1002/anie.201607552 Figure 1: I/V characteristics of a Ni/YSZ//YSZ//CGO//LSCF single cell during co-electrolysis of different H2/CO2 mixtures in dependence of temperature Figure 1

Design and dynamic analysis of a piezoelectric linear stage for pipetting liquid samples

Piezoelectric actuators have been widely used in positioning stages because of their compact size, stepping controllability, and holding force. This study proposes a piezoelectric-driven stage composed of a bi-electrode piezoelectric slab, capacitive position sensor, and capillary filling detector for filling liquid samples into nanopipettes using capillary flow. This automatic sample-filling device is suitable for transmission electron microscopy image-based quantitative analysis of aqueous products with added nanoparticles. The step length of the actuator is adjusted by a pulse width modulation signal that depends on the stage position; the actuator stops moving once the capillary filling has been detected. A novel dynamic model of the piezoelectric-driven stage based on collision interactions between the piezoelectric actuator and the sliding clipper is presented. Unknown model parameters are derived from the steady state solution of the equivalent steady phase angle. The output force of the piezoelectric actuator is formulated using the impulse and momentum principle. Considering the applied forces and related velocity between the sliding clipper and the piezoelectric slab, the stage dynamic response is confirmed with the experimental results. Moreover, the model can be used to explain the in-phase slanted trajectories of piezoelectric slab to drive sliders, but not elliptical trajectories. The maximum velocity and minimum step length of the piezoelectric-driven stage are 130 mm s−1 and 1 μm respectively.