Standard Samples Research Articles

Efficient, Low-Cost, and High-Throughput Sodium Dodecyl Sulfate (SDS) Removal from Protein Digests Using Weak-Anion Exchange.

Sodium dodecyl sulfate (SDS) plays a pivotal role in protein denaturation, tissue extraction, and protein mass-based electrophoretic separations. However, even modest concentrations of SDS can cause column overpressure, retention time shifts, and ionization signal suppression during liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses. Thus, SDS removal is a critical step for LC-MS/MS analysis of protein digests containing SDS. This study describes an inexpensive and high-throughput method to remove SDS from protein digests using weak-anion exchange (WAX) resins in 96-well filter plates. Requiring less than 3 min, this method can reduce SDS concentrations from 0.1-0.4% to less than 5 ppm and from 0.6-1% to less than 100 ppm. After SDS removal, the recoveries of unmodified tryptic peptides and phosphorylated peptides (at 94.3 nM) were ∼90% and ∼70%, respectively. Additionally, when using aqueous 1% SDS to solubilize trastuzumab-spiked mouse serum and subsequently removing the SDS using the WAX resin, quantitation of trastuzumab exhibited excellent linearity (R2 = 0.9996) together with a low coefficient of variation (<10%). Calculated concentrations were within 20% of the expected value for spiked standard samples (0.5, 1, and 2 μg/mL trastuzumab in mouse serum). The method is about 20× more cost-effective versus commercialized SDS removal kits and both the resin and filter plate are readily available, so the method should easily transfer to other laboratories.

Research Advances in Removal Efficiency and Mechanism of Microplastics in Drinking Water Treatment Plants

Microplastics, as a novel type of environmental pollutant, have attracted notable attention in environmental research due to their widespread distribution and potential biological toxicity. Drinking water treatment plants play a crucial role in ensuring the safety of the water supply, with a particular focus on the removal efficiency of microplastics in drinking water treatment plants. Different treatment processes in water plants exhibit various removal efficiencies of microplastics and they operate through distinct removal mechanisms. To comprehensively analyze the removal efficiency and mechanism of microplastics in drinking water treatment plants, this study first examined the abundance and removal efficiency of microplastics of the influent and effluent of drinking water treatment plants. Subsequently, this study reviewed the removal efficiency and mechanism of four commonly used treatment processes： coagulation/flocculation/sedimentation, sand filtration, membrane filtration, and disinfection. The shortcomings and gaps in current studies were also pointed out. Finally, the assessment of microplastics abundance and human exposure in tap water was summarized and the future research direction was prospected from the perspectives of standardized sampling detection methods, nanoplastic detection, microplastics release in water supply systems, and risk assessment.

Rubidium Isotope Measurements of Low‐Rb Geological Materials by MC‐ICP‐MS

The rubidium (Rb) isotope system has the potential to trace planetary evolution, magmatic‐fluid interaction and chemical weathering. These applications are based on Rb isotope measurement results with precisions fit for purpose, but measurements of low‐Rb geological materials are challenging due to large sample consumption and overload of ion‐exchange resin. Here we developed a measurement procedure for Rb isotope data (δ87RbSRM984) of low‐Rb geological materials using MC‐ICP‐MS. Using an Aridus III desolvator and Ni standard sampler + Ni X skimmer cone combination, the Rb loading amount was reduced significantly to 20 ng. A comparison between two methods for instrumental mass‐bias correction, the sample‐standard bracketing and combined sample‐standard bracketing and internal (Zr) normalisation (C‐SSBIN), shows that C‐SSBIN could produce Rb isotope data with better intermediate measurement precisions but strictly restricted to optimal Zr/Rb ratio. The robustness of this method was demonstrated by monitoring δ87RbSRM984 data of two in‐house Rb isotope standards, replicates, some reference materials with δ87RbSRM984 values previously reported, and element‐doped and matrix‐spiked synthetic solutions. Based on repeated measurements of Rb isotope standards and reference materials, the long‐term (over one year) intermediate precision was better than 0.05‰ (2s, standard deviations). We additionally recommend thirteen reliable reference materials for future Rb isotope ratio measurements.

Fast and in-situ electrodeposition of MXene/AuNPs composite for multiplexed and sensitive detection of infectious biomarkers using an electrochemical biosensor

Rapid, accurate, and cost-effective strategies for the multiplexed and quantitative detection of multiple infectious disease biomarkers are still lack in hospital. Here, we introduce a multiplexed screen-printed electrode for the simultaneous detection of three infectious disease biomarkers: HBsAg, anti-HIV, and anti-TP. The electrode modified with in-situ deposition of gold nanoparticles (AuNPs) and MXene multilayered nanosheets. Comprehensive characterization confirms the morphology and electrochemical response of the AuNPs&MXene modified screen-printed electrode (AuNPs&MXene-SPE). AuNPs&MXene composite contributes to enhance sensitivity by maximizing surface area and improving electron transfer efficiency. The AuNPs&MXene-SPE exhibits outstanding detection performance for HBsAg, anti-HIV, and anti-TP. The AuNPs&MXene-SPE sensors achieve broad detection ranges (0.05–1000 ng/mL for HBsAg, 0.35–140 ng/mL for anti-HIV, and 0.25–100 ng/mL for anti-TP) accompanied by low limits of detection (0.01, 0.11, and 0.10 ng/mL, respectively). Applied to standard serum samples, the sensors showcase precision with relative standard deviations consistently below 5.0 %, affirming their suitability for complex solution environments. These sensors offer notable advantages, including cost-effectiveness, rapid response, high sensitivity, and specificity, eliminating the necessity for expensive equipment, which open avenues for the realization of point-of-care testing (POCT).

Microstructural characteristics, electrical conductivity and mechanical properties of Cu matrix composites reinforced with dual-phase borides

The effect of boride content on the microstructure, electrical conductivity, and mechanical properties of TiB2-MB2/Cu composites (M=Cr, Mo, and Zr) was systematically investigated. The composites were prepared via spark plasma sintering. The results indicated that the double borides were uniformly distributed in the Cu matrix without visible agglomeration, and excellent interfacial bonding was achieved between the borides and the Cu matrix. The electrical conductivity of the Cu composite with 5 wt.% TiB2 and 15 wt.% ZrB2 increased by 503 % compared to the Cu-20 wt.% TiB2 composite. However, the hardness of the Cu composite with 5 wt.% TiB2 and 15 wt.% ZrB2 decreased by only 22 %. The wear resistance of the composites was significantly enhanced due to the synergistic effect of the dual-phase boride particles. The wear resistance of the Cu composite with 5 wt.% TiB2 and 15 wt.% ZrB2 was 4.12 times higher than that of the Cu-20 wt.% TiB2 composite standard sample when tested under an applied load of 10 N. The worn surface of the composites exhibited minimal roughness. Therefore, the Cu matrix composites with dual-phase borides achieved desirable comprehensive performance in terms of electrical, mechanical, and tribological properties.

The Recycling Use of Concrete Waste as Aggregate to Produce Different Types of Concrete

The present study depends on two types of concrete: the first and second samples belong to Portland cement with a high strength of 52.5 R, and ordinary Portland cement with a normal strength of 42.5 N, respectively. The physical tests for these two samples according to Iraqi Standard Specification No. 5 of 2019 were conducted. Whereas the third and fourth samples of concrete waste were taken from Mosul City and Al-Anbar Governorate. The concrete waste samples were broken into different-size particles as a fine and coarse aggregate using a mechanical crusher (Los Angeles). According to the Iraqi Standard Specification No. 45 (1984, the Physical and chemical tests for both fine and coarse natural aggregate and recycled concrete waste were conducted. The physical and mechanical results of the recycled aggregate testing samples were found to be within the limits of specifications, in which a reference concrete was made from the standard cement samples with natural aggregate for comparison. The natural aggregate was replaced with 100% recycled aggregate, and its behavior was studied through mechanical properties tests, including compressive strength, flexural resistance, and direct tensile resistance within 7 and 28 days. The results show a decrease in the compressive, flexural, and direct tensile strength in the subjected samples compared to the reference specimens. The study concluded that a 100% replacement ratio of coarse and fine recycled aggregate can be used successfully with different types of cement to obtain a new type of concrete that can be used in several engineering fields. The mechanical properties of the new concrete depend mainly on the type, class and quality of the natural cement even on the properties of the recycled aggregate.

Influence of Kazakhstan’s Shungites on the Physical–Mechanical Properties of Nitrile Butadiene Rubber Composites

This study presents data on the use of shungite ore (the Bakyrchik deposit, Kazakhstan) and its concentrate as fillers in elastomer composites based on nitrile butadiene rubber. In addition to carbon, these shungite materials contain oxides of Si, Fe, K, Ca, Ti, Mn, and Al. The shungite concentrate was obtained through a flotation process involving five stages. The chemical composition analysis of these natural fillers revealed that during flotation, the carbon content increased 3.5 times (from 11.0 wt% to 39.0 wt%), while the silicon oxide content decreased threefold (from 49.4 wt% to 13.6 wt%). The contents of oxides of K, Ca, Ti, Mn, and Al decreased by less than 1%, and iron oxide content increased by 40% (from 6.7 wt% to 9.4 wt%). The study explored the impact of partial or full replacement of carbon black (CB) of P 324 grade with the shungite ore (ShO) and the shungite concentrate (ShC) on the vulcanization process and the physical–mechanical properties of the rubber. It was found that replacing CB with ShO and ShC reduces Mooney viscosity ML (1 + 4) 100 °C of the rubber compounds by up to 29% compared to the standard CB-filled sample. The use of the shungite fillers also increased scorch time (ts) by up to 36% and cure time (t90) by up to 35%. The carbon content in the shungite fillers had little influence on these parameters. Furthermore, it was demonstrated that replacing 5–10 wt% of CB with ShO or ShC improves the tensile strength of the rubber. The results of the flotation enrichment process enable the assessment of how these shungite fillers affect the properties of the composites for producing rubbers with specific characteristics. It was also found that substituting CB with ShO or ShC does not significantly affect the rubber’s resistance to standard oil-based media. The findings indicate that Kazakhstan’s shungite materials can be used as fillers in rubber to partially replace CB.

Low-Consumption and High-Efficiency Isotope Analysis by Microultrasonic Single-Droplet Nebulization Sampling Multicollector Inductively Coupled Plasma Mass Spectrometry.

Metal stable isotopes are increasingly applied in various fields, including planetary science and medical research, highlighting the need for isotope analysis methods capable of handling precious and microvolume samples. This study introduces a novel, low-consumption, high-efficiency isotope analysis method using MC-ICP-MS based on microultrasonic single-droplet nebulization (MUSDN). The proposed MUSDN enables the complete nebulization of microliter-sized droplets, delivering high-sensitivity transient analytical signals with a duration of several seconds. Under optimized conditions, MUSDN exhibited significantly enhanced sensitivity compared to conventional pneumatic nebulization, achieving 17-fold and 12-fold improvements for 7Li and 63Cu, respectively. The achieved external precisions (2SD) for δ7Li and δ65Cu were 0.3 and 0.08‰, with single analysis consuming only 1 ng of Li and 2 ng of Cu, respectively. This represents a reduction in sample consumption by 1-2 orders of magnitude compared to conventional PN-MC-ICP-MS while also improving the analysis speed by at least 10-fold due to rapid residual washout. Furthermore, our method demonstrated superior δ65Cu analytical precision compared to other high-sensitivity transient analysis methods (0.19‰ with a laser ablation system) with similar sample consumption. Finally, the accuracy of the proposed method was validated through the analysis of geological CRMs, serum CRMs, in-house standard samples, and a series of real serum samples. This novel isotope analysis method provides a promising approach for isotope applications involving precious and microvolume samples.

Ternary one-dimensional photonic crystal biosensors for efficient bacteria detection: Role of quantum dots and material combinations

A ternary one-dimensional photonic crystal biosensor was proposed for quick and easy bacterial detection. The Air/(AMB)N/D/(AMB)N/Glass structure is formed by a defect layer between two identical periodic structures filled with samples of normal blood and bacteria-infected blood. Three categories of inorganic, organic, and inorganic/organic hybrid materials were used to make the four combinations of proposed photonic crystal biosensors. Aluminum Gallium Nitride (AlxGa1-xN) quantum dots, Gallium Arsenide (GaAs), silica, and polyaniline polymer have been used in the proposed structures to observe and compare their effects are in the infrared and visible regions. The results indicate that incorporating AlxGa1-xN and GaAs quantum dot layers has increased the sensitivity. These designs have two photonic band gaps with multiple suitable detection modes in infrared and visible regions with an approximately linear behavior. A standard blood sample (TBN) and bacterial samples (TB1 to TB7) were distinguished using the optimal parameters.

A fish community comparison upstream and downstream a high-head dam on the Upper Mississippi River

Abstract Standardized sampling is useful for detecting and monitoring variations in fish communities and the establishment and spread of invasive species. Lock and Dam 19, a high-head dam with a 10- meter hydraulic head, creates the largest impoundment on the Upper Mississippi River. Upstream, Pool 19 is characterized by static water levels and expansive macrophyte beds. Downstream, Pool 20 is characterized by lotic conditions and sparse vegetation. Lock and Dam 19 serves as barrier to upstream migration of fishes, particularly Bigheaded carp (Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molotrix). There is limited standardized fisheries data available for Pools 19 and 20, particularly in off-channel areas. In 2013 and 2014, we conducted two years of standardized electrofishing in Pools 19 and 20 to 1) detect a presence of adult or juvenile Bigheaded carp, 2) quantify differences in fish community structure (i.e., relative abundance of species) between Pools 19 and 20 and among strata (i.e., backwater, side channel, main channel, and impounded reaches), and 3) quantify hydrological differences (i.e., water quality variables) between Pools 19 and 20 and among strata. We detected two Bigheaded carp upstream Lock and Dam 19, the first to be documented using a standardized collection method. We used permutational multivariate analysis of variance using distance matrices (veganR package version 2.6-4) to determine that fish community structure differed significantly between pools (P&amp;lt; 0.01) and among strata (P&amp;lt; 0.01), except between main and side channel borders. We determined water quality variables differed significantly between the pools and among strata demonstrating strata proportional differences may drive the fish community differences between Pools 19 and 20. We have demonstrated that expanding standardized sampling efforts to Pools 19 and 20 is important to understand long-term changes in fish assemblages and the effects of Lock and Dam 19 on the ecology of the Upper Mississippi River.

Application of continuous wavelet transforms for simultaneous estimation of domperidone and lansoprazole in capsule formulations

UV–Vis spectroscopy remains essential in pharmaceutical research and quality control due to its accessibility, simplicity, and effectiveness. However, overlapping spectra resulting from multicomponent drug formulations present challenges. Here, we describe a signal processing strategy using continuous wavelet transform (CWT) to resolve overlapping spectra of domperidone (DMP) and lansoprazole (LSP) for simultaneous quantification. Three different wavelet functions (Symlets 3, Coiflets 1, Daubechies 10), were found to be suitable for this purpose. Linear calibration curves were constructed using the CWT zero-crossing technique and the methods were validated by analyzing a set of synthetic mixtures, intra-and inter-day samples, and standard addition samples. The assay results of commercial capsule samples were compared with those obtained by derivative spectroscopy, and no significant statistical difference was observed. The proposed CWT methods demonstrated good compliance with the label claims and proved to be reliable, versatile, fast, and cost-efficient analytical methods without the need for preliminary separation procedures.

Evaluation of an alternative centrifugation protocol for reducing total turnaround time

Abstract Objectives Centrifugation is a key process that should be controlled to ensure an adequate sample quality. To achieve rapid, standardized, and consistent sample centrifugation, we aimed to evaluate an alternative centrifugation protocol and its impact on the results of 20 biochemical determinations in serum. Methods The study included 45 ambulatory patients. Two serum-separating tubes were collected from each patient (Becton Dickinson (BD) Vacutainer® SST™ II Advance, 8.5 mL Ref. 366468). One of the tubes was centrifuged at 2530 × g for 10 min (control method), while the other tube was centrifuged under alternative centrifugation conditions, namely 2530 × g for 7 min. Results The analysis of results revealed that calcium, total bilirubin, and magnesium exhibited a constant and proportional systematic bias. However, considering the proportional mean difference, all analytes met the desirable bias performance established by our laboratory, except for magnesium, which met the minimum bias criteria. Conclusions Our study demonstrates that both centrifugation protocols are interchangeable for measuring the studied analytes, thereby ensuring adequate sample quality.

Application of improved matrix dilution method in quantitative analysis of Ni-Co-Mn ternary precursor

Abstract When using energy-dispersive X-ray fluorescence (EDXRF) to analyze Ni-Co-Mn (NCM) samples, if the standard sample's concentration greatly differs from the unknown sample's concentration, the traditional matrix dilution method requires repeated dilution and measurement. This makes the process time-consuming and labor-intensive. This study proposes an improved matrix dilution method to reduce sample preparation and analysis. This method first establishes a functional relationship model between the dilution factor and the characteristic X-ray intensity. Then the characteristic X-ray intensity of the analyzed element can be calculated by this model, avoiding unnecessary dilution and measurement steps. To verify the effectiveness of this method, the dilution factors and characteristic X-ray intensities of the test samples were fitted using the established functional relationship. The fitting results showed that the fitting coefficients of determination of the Mn, Co, and Ni were all 0.999. Quantitative analysis was performed on the characteristic X-ray intensity fitting values and measured values of the test samples. The results showed that the quantitative results of the two were consistent. The average error of the three elements for both methods was 1.1% and 0.7%, respectively. It shows that through the established functional relationship, the characteristic X-ray intensity can be effectively calculated by the dilution factor. This method can be applied to samples with identical elements and proportions of target elements, but with different concentrations, using the same set of standard samples.

Hematological parameters of the European hake (Merluccius merluccius) in Toroneos Gulf, northern Greece: A case study

Background: The European hake (Merluccius merluccius) is a commercially valuable demersal species widely distributed in the Mediterranean Sea. Assessing the condition of fish populations in their natural habitats is challenging due to the lack of reliable reference points. Objective: This study aimed to utilize hematological analysis as an economical method to evaluate the physiological and health status of European hake, addressing the gap in hematological data for this species. Methods: Blood samples were collected from the caudal vein of 40 adult European hakes caught from the Toroneos Gulf (northern Greece) using a commercial bottom otter trawl. An automated hematological analyzer was used to assess hematological parameters alongside biometric and biological indices. Results: Female hakes showed significantly higher white blood cell (WBC) counts, thrombocyte (TC) counts, and red cell distribution width (RDW) than their male counterparts. Strong correlations were observed among various hematological parameters, notably between WBC and red blood cells (RBCs), hematocrit (Ht), and hemoglobin (Hb); between RBC and both Ht and Hb; between TC and both mean platelet volume and platelet distribution width (PDW); and between mean corpuscular Hb concentration and RDW. Significant differences were noted in RBCs, Hb, and Ht compared to data from wild-caught European hake populations in Argentina and Denmark. Both trawling depth and duration were found to significantly affect RBC, WBC, Hb, and Ht values, while having no notable impact on TC. Fish captured at an average depth of 80 m and with a trawling duration of 30 min exhibited significantly elevated hematological indices. Conclusion: This study demonstrates that hematological analysis is a valuable, cost-effective tool for assessing the physiological and health status of European hake populations in the Mediterranean. Notable differences in hematological parameters based on sex, as well as significant correlations among key blood metrics, underscore the importance of understanding species-specific hematological profiles. The influence of trawling depth and duration on certain blood parameters highlights the need for standardized sampling protocols in population health assessments. These findings contribute essential baseline hematological data for European hake, facilitating more informed fisheries management and conservation strategies.

Determination of Am full isotope compositions (241Am, 242Am, 243Am) at trace level by multiple-collector - ICP-MS with a desolvation device for sample introduction

Americium isotopes are crucial in various nuclear-related fields such as nuclear fuel cycle, nuclear forensics and nuclear safeguards. This study introduces enhanced methodologies for precise determination of 242Am/241Am and 243Am/241Am in trace americium by employing Multiple Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS) and Total Evaporation-Thermal Ionization Mass Spectrometry (TE-TIMS). We established a standard-sample bracketing (SSB) method with uranium-certified reference material (U CRM) to correct the mass fractionation and ion counter gain yield among different isotopes in MC-ICP-MS. The new methods were successfully applied to an aliquot of an 241Am progeny sample, an 241Am activity standard solution and an in-house Am isotopic working standard, achieving detection limits of 10−7 for 242Am and 243Am. Analysis requires an aliquot containing about 1 ng of 241Am for MC-ICP-MS with a desolvation device for sample introduction and about 5 ng for TE-TIMS to determine 242Am/241Am ratios close to 10−5 and 243Am/241Am ratios close to 10−4, with observed relative standard deviations of 0.2 %. Comparative analysis of 242Am/241Am and 243Am/241Am using classical TE-TIMS and the newly developed MC-ICP-MS confirms their consistency within uncertainties, validating the precision of MC-ICP-MS in americium isotope ratio determination. These findings indicate that the 241Am activity standard sample was directly sourced from irradiated material rather than from a 241Pu solution, highlighting the methodology's applicability to nuclear forensics and nuclear fuel cycles.

A recommended sampling strategy for genetic identification of Second World War victims in Slovenia

Skeletonized human remains from Second World War mass graves in Slovenia are a major challenge in genetic identification, and bones with a high DNA yield must be selected for successful identification. The goal of this study was to construct skeletal sampling strategy recommendations through comparison of the most appropriate groups of skeletal elements. Altogether, 566 bones and teeth from the same mass grave were compared, half analyzed in this study and half in previous studies performed by our group. After anthropological examination, mechanical and chemical cleaning was performed, followed by bone and tooth powdering. Total demineralization of 0.5 g of bone and tooth was followed by extraction and purification of DNA with a Biorobot EZ1 device (Qiagen). The qPCR PowerQuant kit (Promega) was used to measure the amount of DNA, and statistical analysis was performed. Skeletal elements were selected according to known better preservation of DNA in the human body, and they were arranged in seven groups: petrous bone, long bones (femur and tibia), torso bones (first rib and 12th vertebra), metacarpals, metatarsals, short and sesamoid bones (talus, navicular, medial cuneiform, cuboid, calcaneus, and patella), and teeth. Sampling strategy recommendations were constructed based on DNA quantity and quality results. The petrous bone group, metacarpal group, torso bone group, and short and sesamoid bone group produced the highest DNA yields. Accordingly, in addition to standard sampling of long bones (femurs and tibias) and teeth, those additional bone types should be collected for Slovenian Second World War victim identification.

Long-term reproducibility improvement of LIBS quantitative analysis based on multi-period data fusion calibration method

Long-term reproducibility is one of the important problems that urgently need to be solved in the quantitative analysis of laser-induced breakdown spectroscopy (LIBS). In this work, a new calibration method based on multi-period data fusion was proposed. Under the same experimental equipment and parameters, LIBS data collected at different times were fused together to establish calibration models. The spectra of the same set of standard samples were collected once a day for 20 days, the spectral data from the first 10 days were used as the training set for the calibration model, and the data from the last 10 days were used as the test set. As a comparison, three types of calibration models of four elements (Mn, Ni, Cr, and V) were established, including the internal calibration model (IS-1) based on the data from first day, multi-period data fusion internal calibration model established using internal calibration (IS-10) and genetic algorithm based back-propagation artificial neural network (GA-BP-ANN) based on the data from first 10 days. The test set spectral data were used to verify the prediction effect of the above three models. It was found that the GA-BP-ANN models have the lowest average relative errors (ARE) and the average standard deviations (ASD). Therefore, the proposed multi-period data fusion GA-BP-ANN model provides a novel method for improving the reproducibility of LIBS long-term repeated measurement.

Design and fabrication of a dual laser Raman spectrometer with a single one-dimensional CCD detector

The combination of two spectrometers in dual-laser Raman devices without the need for moving parts represents a significant advancement. This study focuses on design and fabrication of a dual spectrometer with no moving components, allowing data to be gathered using a single detector. This instrument consists of two Czerny–Turner optical arrangements which is symmetrically merged. Dual spectrometer single detector has two light inputs, each of them, concentrating the light separately on a one linear charge-coupled device detector through two independent optical paths. In this innovative spectrometer design, no optical moving parts are used, and therefore, the wavelength displacement error in repeating the spectroscopic experiment is zero. The independent nature of the optical paths enables the optimization of each spectrometer arrangement without affecting the other. The final spectrometer has a spectral resolution of 4.6 and 6.11 cm− 1 for Full Width at Half Maximum across the wavelength ranges of 532 to 708 nm and 784.65 to 1100 nm, respectively. Switching between the two different acquisition setups can be done seamlessly and quickly, with the ability to record approximately 2000 spectra per second. Standard neon and mercury-argon lamps’ atomic radiation spectra, along with Raman scattering data from a cyclohexane standard sample, were successfully recorded using laser wavelengths of 532 nm and 784.65 nm.

Application of electronic time focusing at the engineering materials diffractometer in the China spallation neutron source

The Engineering Materials Diffractometer (EMD) is a new and critical addition to the instrument suite of the China Spallation Neutron Source (CSNS). It will support extensive research activities and applications on modern engineering materials. Based on the large multielement detector array, the electronic time focusing method has been successfully applied to deal with the raw neutron data and the constants Ci, corresponding to each single pixel in the detector array, have been calculated using the relation between the time of flight of the Bragg peaks in standard Si sample and their particular d-spacings. The instrument resolution in the mode best suited for strain measurements (∼0.35%) is interpreted and verified as a function of d-spacing via Si and La11B6 standard samples. The results are found to be consistent with the McStas simulations of the instrument physical design.

The effect of single walled carbon nanotubes on conductivity and thermal properties of glass fiber reinforced composites

Abstract This paper reports on a comprehensive study of the effect of single-walled carbon nanotube (SWCNT) on the alternating current (AC) conductivity, thermal and morphological properties of the unsaturated polyester based glass fiber reinforced polymer composite (GFRPC). AC conductivity measurements were carried out using the impedance spectrum and thermal measurements were carried out using differential scanning calorimetry (DSC) at a temperature range of 24-900 °C and heating rates of 20 °C/min. Impedance results showed that the conductivity behavior in the nanotube-loaded composite laminate obeys a Jonscher-type mechanism. At low frequencies, the conductivity value remains almost constant for the doped material and takes the value of 10-5 S/cm. It is observed that the AC conductivity starts to increase after the critical frequency value of approximately 103 Hz and increases up to 10-2 S/cm due to hopping and tunneling mechanisms caused by space charge polarization accumulated in the local regions at high frequencies. The pure material with an insulating nature also exhibited a typical insulating behavior. Thermal testing showed that nanotube reinforcement increases thermal conductivity in three different directions. DSC thermocurves analysis also revealed that the addition of carbon nanotubes increased the glass transition temperature of the material from 180°C to 190°C. The scaling and fractal analysis methods were also applied to obtain hetero morphological structure of materials. The fractal analysis results indicated that carbon nanotube doping to the standard sample increases the coating rates, scalability and heterogeneity of the solid phase surface of the sample. The coating rates of composite surfaces were calculated as 45% and 36%, respectively. Morphology analysis revealed that the probability of finding surface particles for the nanotube-doped sample decreased compared to the undoped sample, but the fractal dimension value increased. While this value was 1.83 in the pure sample, it increased to 1.92 in the nanotube material.