Characteristics Of Different Samples Research Articles

A novel method to determine the optimal threshold of SEM images

The determination of threshold is crucial for the binarization of scanning electron microscopy (SEM) images. In this paper, a new method for determining the optimal threshold considering the three-dimensional characteristics of shale samples is proposed based on GIS. Firstly, the SEM images of seven shale samples at six magnifications are 3D reconstructed and visualized using ArcMap and ArcScene. Relevant parameters are obtained to calculate the 3D porosity φ3D. Secondly, the effects of magnification and segmentation size on φ3D are considered. By establishing the relationship between threshold and porosity, the optimal magnification, optimal segmented size and optimal threshold are obtained for the seven shale samples, respectively. Finally, the optimal threshold obtained by this method is applied to the finite element model of the pore structure and fractal dimension, respectively. The results show that the overall effect of 3D reconstruction and visualization is good. The optimal thresholds of seven shale samples are 94, 93, 105, 93, 81, 98 and 88, respectively. The porosity obtained from the finite element model of the pore structure based on the optimal threshold is suitable for SEM images with larger sizes. The fractal dimensions obtained based on the optimal threshold are all larger than those obtained at six magnifications, which can characterize a more complex pore structure and a more inhomogeneous pore size distribution. This method fully considers the three-dimensional characteristics of different samples and improves the accuracy of the threshold study of SEM images.

Phytochemical analysis and hepatotoxicity assessment of braised Polygoni Multiflori Radix (Wen-He-Shou-Wu).

Polygoni Multiflori Radix (PMR) is a medicinal herb commonly used in China and Eastern Asia. Recently, the discovery of hepatotoxicity in PMR has received considerable attention from scientists. Processing is a traditional Chinese medicine technique used for the effective reduction of toxicity. One uncommon technique is the braising method-also known as 'Wen-Fa' in Chinese-which is used to prepare tonics or poisonous medications. Braised PMR (BPMR)-also known as 'Wen-He-Shou-Wu'-is one of the processed products of the braising method. However, the non-volatile components of BPMR have not been identified and examined in detail, and therefore, the hepatotoxic advantage of BPMR remains unknown. In this study, we compared the microscopic characteristics of different samples in powder form using scanning electron microscopy (SEM), investigated the non-volatile components, assessed the effects of different processed PMR products on the liver, and compared the differences between BPMR and PMR Praeparata recorded in the Chinese Pharmacopoeia (2020 edition). We found that the hepatotoxicity of BPMR was dramatically decreased, which may be related to an increase in polysaccharide content and a decrease in toxic substances. The present study provides an important foundation for future investigations of the processing mechanisms of BPMR.

A study on the measurement of GSR with bloodstains by ICP-MS

Abstract In forensic laboratories, analytical investigations of gunshot residues (GSRs) are usually conducted by scanning electron microscopy (SEM) in combination with energy dispersive X-ray (EDX) microanalysis. If GSRs are covered with bloodstains, SEM cannot detect them. In this study, an inductively coupled plasma mass spectrometry (ICP-MS) method is proposed to solve this problem. Results show that bloodstains did not interfere with GSRs and low-level elements are detected. Qualitative and quantitative analyses of Sn, Sb, Ba, and Pb elements in GSRs are also carried out. In addition, testing of GSRs from a type 95–1 rifle and a type 92 pistol is also proposed. Different pretreatment methods are adopted according to the characteristics of different samples. Our investigations suggest that the proposed method has the advantages of low detection limit and high sensitivity and it can be very important in expert testimony.

Study on the roles of microorganisms and endogenous enzymes in the evolution of metabolic characteristics of lean portion during traditional Chinese bacon processing

This study revealed the roles of microorganisms and endogenous enzymes in evolution of the metabolic characteristics of the lean portion of traditional Chinese bacon by exploring the changes in microbial succession, metabolic characteristics, lipid oxidation, lipid hydrolysis, lipoxygenase activity, lipohydrolase activity, protein degradation, and environmental factors during processing. The results showed that Proteobacteria and Firmicutes were the dominant phyla in the lean portion of traditional Chinese bacon, and 16 core genera (relative abundance > 1 %) were identified at the genus level. Significant differences were observed in the metabolic characteristics of different samples. A total of 23 differential metabolites were identified in positive and negative ion modes (P < 0.05, variable importance in the projection > 1.5). Peroxide value (POV), thiobarbituric acid reactive substances value (TBARS), proteolysis index (PI) and the degree of lipid hydrolysis increased during the processing. Phospholipids were the main hydrolysis substrates. Lipoxygenase activity increased first and then decreased, while lipohydrolase activity decreased gradually. The results of canonical correspondence analysis indicated that the salt content was the main environmental factor affecting the microbial composition. The results of Spearman correlation analysis and comprehensive discussion showed that the metabolic characteristics of the lean portion of traditional Chinese bacon during the curing period were mainly due to the catalysis of the endogenous enzymes in meat and the extracellular enzymes secreted by bacteria such as Brochothix, Acinetobacter, Psychrobacter, etc. The extracellular enzymes secreted by Salinivibrio, Vibrio, and Staphylococcus in light-fermented meat and final meat might have important contributions to the metabolic characteristics.

Comprehensive insights into the evolution of microbiological and metabolic characteristics of the fat portion during the processing of traditional Chinese bacon

Both lean meat and fat together contribute to the consumer impression of traditional Chinese bacon. The quality of this meat product is mainly dependent on numerous biochemical reactions and microbes. For the first time, this study reveals the microbial community succession and metabolic characteristics of the fat portion during the processing of traditional Chinese bacon by high-throughput sequencing and untargeted metabolomics (ultra-high performance liquid chromatography, UHPLC). The results showed that Proteobacteria and Firmicutes were the predominant bacterial phyla in traditional Chinese bacon. At the genus level, 15 core genera (relative abundance >1%) were identified, including Salinivibrio, Staphylococcus, Brochothrix, Vibrio, Psychrobacter, Acinetobacter, Carnobacterium, Aeromonas, Pseudomona, Cobetia, Macrococcus, Enterobacter, Kocuria, unclassified-f-Vibrionaceae, and Empedobacter. Distinct separation between different groups were identified by principal component analysis, revealing significant differences in the metabolic characteristics of different samples. A total of 262 metabolites were identified, and most of the metabolites belonged to lipids and lipid-like molecules, of which 60 were identified as differential metabolites. Results of correlation analysis indicated that some differential metabolites were significantly positively correlated with dominant bacteria, such as Salinivibrio, Vibrio, Cobetia and Staphylococcus, which reinforced the fact that microorganisms have an indispensable role in the quality formation of traditional Chinese bacon.

Effect of Loading Direction on the Tensile Properties and Texture Evolution of AZ31 Magnesium Alloy

Samples were cut from an extruded AZ31 magnesium alloy bar for uniaxial tensile and EBSD characterization tests. The long axis and bar extrusion directions were 0° (T0 sample), 45° (T45 sample), and 90° (T90 sample). The effects of loading direction on the tensile behavior, microstructure, and texture evolution of the magnesium alloy were studied. Results show that the obvious mechanical anisotropy of tensile behavior is affected by the loading direction, and the T0 sample with a grain c-axis perpendicular to the extrusion direction has a strong basal texture and high flow stress and yield strength. The loading direction has a significant influence on the microstructure characteristics of different samples, especially the number of {10–12} tensile twins and {10–11} compression twins. Texture evolution results show that the loading direction and the effect of deformation mode on the deformation mechanism lead to variations in texture evolution: the basal slip and prismatic slip during the plastic deformation of the T0 specimen, the compression twin of the T45 specimen, and the tensile twin of the T90 specimen.

The Consequences of Personality Biases in Online Panels for Measuring Public Opinion

Abstract Online surveys, particularly those that draw samples from online panels of experienced respondents, now comprise a large segment of the academic and commercial opinion research markets due to their low cost and flexibility. A growing literature examines the implications of online surveys for data quality, most commonly by comparing demographic and political characteristics of different samples. In this paper, we explore the possibility that personality may differentially influence the likelihood of participation in online and face-to-face surveys. We argue that individuals high in extraversion and openness to experience may be underrepresented, and those low in these traits overrepresented, in professionalized online panels given the solitary nature of repeated survey-taking. Since openness to experience in particular is associated with liberal policy positions, differences in this trait may bias estimates of public opinion derived from professionalized online panels. Using data from the 2012 and 2016 dual-mode American National Election Studies, we compare political preferences and personality traits across parallel face-to-face and online samples. Respondents in the online samples were, on average, less open to experience and more politically conservative on a variety of issues compared to their face-to-face counterparts. This was true especially in 2012, when online respondents were drawn from a large panel of experienced respondents. We also find openness to be negatively related to the number of surveys completed by these respondents. These results suggest that reliance on professionalized survey respondents, who comprise the vast majority of online survey samples, can bias estimates of many quantities of interest.

Effects of sintering temperature and particle size on permeability of functionally gradient composite porous materials prepared by hanging slurry process

Porous materials have excellent functions in filtration and purification, and gradient composite porous materials enrich the product types of porous materials in the same field. In the preparation of metal-ceramic gradient composite porous materials, the matching relationship between the pore morphology and pore size of the metal porous matrix and the coated powder particles will seriously affect the structure and performance of the ceramic membrane. This work mentions the different size range (60, 100, 200 and 400 mesh) of 316 L stainless steel powder particles as the raw materials which are at different sintering temperatures of 1170, 1200 and 1230 °C, the fabrication of porous 316 L stainless steel substrate which was made by hanging slurry preparation of precursor, at the same time using Ar protection at different sintering temperatures (650, 700, 750 and 800 °C) to the preparation of metal-ceramic composite gradient according to different matrix apertures of porous materials. The pore structure, microstructure and morphology characteristics of different samples both of matrix and functionally gradient composite were analyzed and characterized. On the basis of test of permeability of functionally gradient composite porous materials, this kind of composite gradient porous material can be excellent at part of permeability which matrix was made by 400 mesh 316 L stainless steel powder particles at sintering temperature of 1230 °C and then dealed with the process of hanging slurry to became the precursor which ceramic membrane was prepared at sintering temperature of 650 °C. Maximum aperture of the porous substrate filtration precision under the combination of ceramic membrane layer can be increased by 96.3%. By observing the change of pore morphology of porous matrix, this paper aims to make a research of influence of sintering temperature and powder particles size on permeability of the functionally gradient composite porous materials, and also provide a reference for improving the filtration accuracy of existing porous materials.

Multi-mode Microscopic Hyperspectral Imager for the Sensing of Biological Samples

In this work, we develop a multi-mode microscopic hyperspectral imager (MMHI) for the detection of biological samples in transmission imaging, reflection imaging and fluorescence mode. A hyperspectral image cube can be obtained with 5 μm spatial resolution and 3 nm spectral resolution through push-broom line scanning. To avoid possible shadows produced by the high magnification objective with a short working distance, two illumination patterns are designed to ensure the co-axiality of the illumination and detection. Three experiments for the detection of zebrafish and fingerprints and the classification of disaster-causing microalgae verify the good capability and functionality of the system. Based on the detected spectra, we can observe the impacts of β-carotene and melanin in zebrafish, hemoglobin in the fingertip, and chlorophyll in microalgae, respectively. Multi-modes can be switched freely according to the application requirement and characteristics of different samples, like transmission mode for the transparent/translucent sample, reflection mode for the opaque sample and fluorescence mode for the fluorescent sample. The MMHI system also has strong potential for the non-invasive and high-speed sensing of bio or clinical samples.

Physico-chemical characteristics, cooking and texture of polished and brown rice of different varieties sold in Brazil

The diversity of whole rice grains with black and red pericarp has been valued in Brazil due to its different characteristics of color, texture, and also due to the association with health benefits. This work aimed to evaluate the physicochemical, cooking, and textural characteristics of different samples of polished and whole rice grains from different varieties marketed in Brazil. A total of 28 samples were collected and divided into 6 groups: polished white rice, white polished parboiled rice, whole white rice, whole red rice, whole black rice, and whole wild rice. Moisture content, crude protein, ash, mineral content, hardness, and adhesiveness were analyzed. The cooking quality was evaluated through the determination of cooking time, swelling ratio, and volume expansion ratio. A strong correlation between the protein content and the hardness value of cooked grains was observed. The polished samples showed the lowest ash and mineral values and the shortest cooking time. A strong correlation was also observed for the volume expansion ratio and hardness of cooked samples. The data obtained contribute to a better understanding of the quality of the rice marketed in Brazil and demonstrate a large variation among samples in terms of physicochemical, cooking, and texture properties.

Source identification of heavy metals in surface sediments from a river in Anhui, China

Mineral resources (such as sulphur, iron, lead, and zinc) are abundant in one of the watersheds in Anhui Province, China. Unfortunately, excessive mining has negatively impacted the surrounding ecosystems and human health. To facilitate planning of the dredging project for the main river in the watershed, identification of the contaminant source(s) of sediments in the river course is critical. This study focuses on the investigation of seven mines and related businesses. Soil samples were collected from tailings piles and sewage outlets from the mines, sediments in the river course, surrounding croplands, and background areas. The concentrations of eight heavy metals (cadmium, mercury, lead, arsenic, chromium, copper, zinc, and nickel) were analysed. Multivariate statistical analyses, combined with the specific site information, were conducted to evaluate the potential sources of heavy metals in river sediments. The results indicated that the concentrations of copper, cadmium, and arsenic exceeded the thresholds in most parts of the river course. The degree of pollution was highest for copper, moderate for cadmium and arsenic, and lowest for lead, zinc, mercury, nickel, and chromium. Based on pollutant characteristics of different samples, the hydrology and hydrogeology in the watershed, and the operational history of the businesses, the primary source(s) of the contamination of heavy metals in river sediments was determined to be the effluents discharged from mine operations. When the effluents containing large amounts of heavy metals-laden suspensions entered the watershed, the suspensions precipitated gradually, leading to the high concentrations of heavy metals in the river sediments.

Preparation and Flavor Characteristics of Alaska Pollock Frame Seasoning Powder by Solid-Phase Maillard Reaction

ABSTRACTThe solid-phase Maillard reaction of Alaska pollock frame (APF) mud with glucose preparation for seasoning powder was investigated. The response surface methodology was used to optimize the production conditions of APF seasoning powder according to the electronic nose and sensory evaluation. The factors affecting the sensory evaluation of the Maillard reaction were glucose addition amount>reaction temperature>reaction time>initial pH value. The optimum process parameters for the APF seasoning powder were as follows: glucose addition 9.79%, temperature 103.25°C, time 70 min, and initial pH value 7.21. The 77 volatile compounds were identified by headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) analysis. The flavor of APF seasoning powder obtained by the Maillard reaction was better than that of the raw APF powder. The aroma characteristics of different samples were detected by electronic nose, and the results were in good agreement with those of GC-MS analysis. The results of the present study demonstrated that the solid-phase Maillard reaction might be a promising method to enhance the volatile flavor of APF powder.

The deteriorated microstructure characteristics of fly ash doped cementitious materials by dissolution

The microstructure differentia of fly ash doped cementitious materials between before and after dissolution was observed by XRD and MIP to analyze the microstructural deterioration characteristics of different samples. Results showed that there were great changes in hydration products, cement clinker and fly ash particles after dissolution. Pore structure evolution during dissolution indicated that the effect of C-S-H decalcification on pore structure was not negligible and the traditional definition between the harmful pore and the harmless pore was not applicable.

Flavor characteristics of shrimp sauces with different fermentation and storage time

The present study investigated the volatile compounds in nearly three-year shrimp sauces and the effects of different fermentation and storage time on the integral aroma characteristics. The 89 volatile compounds were identified by solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) analysis. Compared with the other two samples, the shrimp sauces which fermented and storage for 2 years has the highest umami amino acid content and the better flavor. The results of electronic nose (e-nose) and electronic tongue (e-tongue) detection to distinguish the aroma characteristics of different samples demonstrated good agreement with those obtained by GC-MS analysis. These results suggested that proper fermentation and storage time are critical to the flavor quality of shrimp sauces.

Investigation of Cs(I) and Sr(II) removal using nanoporous bentonite

ABSTRACTBentonites are types of clays made up the dominant constituent of montmorillonite. Four types of nano-porous and nano-structured commercial bentonite clays were studied in detail for their physicochemical and mineralogical properties vs. Cs and Sr adsorption. The instrumental analyses to study samples were X-ray diffraction (XRD), X-ray fluorescence (XRF), Brunauer–Emmett–Teller (BET) surface area measurements, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermogravimetry (TG). The XRF and peaks of XRD patterns at 2θ = 8, 19.9, 35, 55, and 62 clearly indicated that the main component of the bentonite samples was montmorillonite. The BET analysis showed that B1 has the highest specific surface area among the other samples which its single and multiple point BET surface area were equal to 84.85 and 85.94 m2 g−1, respectively. These values represents the amount of montmorillonite and adsorption capacity of samples. The physicochemical, structural and morphological characteristics of different samples were investigated through instrumental analysis. The results of separation processes of Cs(I) and Sr(II) showed 59.75 and 45.5% adsorption capacities for B3 and B2 which were the highest values among the others. The results lead to the conclusion that samples B3 had a good adsorption capacity to remove Cs(I) and Sr(II).

Сравнительная характеристика различных образцов Мугалжарского диатомита

Сравнительная характеристика различных образцов Мугалжарского диатомита

Requisitos para credibilidade da análise sensorial do café

This research to determine the minimum amount of testers was made to ensure the reliability of the sensory analysis of the coffee beverages. It were analyzed the scores assigned by three Q-grader who adopted the international rules from the Cup of Excellence (CoE) methodology.&nbsp;Based on descriptive statistics of the scores the testers assigned to eight sensorial characteristics of different samples for Red and Yellow Catuaí coffees, at the ripe coffee cherry produced in altitudes below and above 900 meters, it was concluded that the most important fact is not on the number of testers involved, but rather on the reliability of the scores they assign. Therefore, the reliability is a measure directly related to the homogeneity for the set of scores assigned by different testers, given the same condition for the evaluation.

Effects of SiO2/Al2O3 Ratios on Sintering Characteristics of Synthetic Coal Ash

This article explores the effects of SiO2/Al2O3 ratios (S/A) on sintering characteristics and provides guidance for alleviating ash depositions in a large-scale circulation fluidized bed. Five synthetic coal ash (SCA) samples with different S/As were treated in a muffle furnace for 12 h at different temperatures (from 773 K to 1373 K, in 100 K intervals). The morphological and chemical results of the volume shrinkage ratio (VSR), thermal deformation analysis by dilatometer (DIL), scanning electron microscope (SEM), X-ray photoelectron spectrometer (XPS), and X-ray diffraction (XRD) were combined to describe the sintering characteristics of different samples. The results showed that the sintering procedure mainly occurred in the third sintering stage when the temperature was over 1273 K, accompanied with significant decreases in the VSR curve. Excess SiO2 (S/A = 4.5) resulted in a porous structure while excess Al2O3 (S/A = 0.5) brought out large aggregations. The other three samples (S/A = 1.5, 2.5, 3.5) are made up of an amorphous compacted structure and are composed of low fusion temperature materials (e.g., augite and wadsleysite.). Sintering temperatures first dramatically decrease to a low level and then gradually rise to a high level as S/A increases, suggesting that Al2O3-enriched additives are more effective than SiO2enriched additives in alleviating depositions.

Automated quantification of one-dimensional nanostructure alignment on surfaces

A method for automated quantification of the alignment of one-dimensional (1D) nanostructures from microscopy imaging is presented. Nanostructure alignment metrics are formulated and shown to be able to rigorously quantify the orientational order of nanostructures within a two-dimensional domain (surface). A complementary image processing method is also presented which enables robust processing of microscopy images where overlapping nanostructures might be present. Scanning electron microscopy (SEM) images of nanowire-covered surfaces are analyzed using the presented methods and it is shown that past single parameter alignment metrics are insufficient for highly aligned domains. Through the use of multiple parameter alignment metrics, automated quantitative analysis of SEM images is shown to be possible and the alignment characteristics of different samples are able to be quantitatively compared using a similarity metric. The results of this work provide researchers in nanoscience and nanotechnology with a rigorous method for the determination of structure/property relationships, where alignment of 1D nanostructures is significant.

Determination of the effects of different washing processes on aroma characteristics in silver carp mince by MMSE–GC–MS, e-nose and sensory evaluation

The present study investigated the volatile compounds of silver carp mince and the effects of washing processes on the integral aroma characteristics and aroma-active compounds (AACs) of the mince. 57 volatile compounds were identified by monolithic material sorptive extraction (MMSE) and GC–MS analysis, and 13 volatile compounds with odor activity values greater than 1 (OAVs>1) were further selected as AACs contributing primarily to the integral aroma profile of silver carp. Washing methods affected the overall aroma profiles of fish samples by washing away or facilitating the release of AACs but to different extents. Compared with water washing, washing with saline and weak alkaline solution removed more AACs. Washing with water three times (T2) exhibited a relatively stronger removal effect on most AACs compared to washing with water twice (T1). Washing with a high concentration of saline (T4) produced a strong removal effect on AACs. The results of sensory evaluation and electronic nose (e-nose) detection for distinguishing the aroma characteristics of different samples demonstrated good agreement with those obtained by OAV analysis.