Intensity Of Mg Research Articles

Classification of kimchi using laser-induced breakdown spectroscopy and k-nearest neighbors modeling

This study introduces a novel application of Laser-Induced Breakdown Spectroscopy (LIBS) combined with k-nearest neighbors (KNN) modeling to classify the origin of kimchi. Using the spectral intensities of Mg II at 279 nm and K I at 766 nm, we achieved a classification accuracy of 92.8 %. This method effectively leverages regional differences in salt supply chains impacting kimchi's elemental composition. The innovation lies in applying the interclass distance method for variable selection in LIBS analysis, enhancing the interpretability and accuracy of food classification. Compared to traditional elemental analysis techniques, LIBS offers a practical, cost-effective solution for rapid field analysis with minimal sample preparation. This study not only demonstrates the potential of LIBS for food authenticity but also provides insights for developing accurate methods for detecting Mg and K in various food products, contributing to advancements in food quality control.

Spectral properties of ablating meteorite samples for improved meteoroid composition diagnostics

Emission spectra and diagnostic spectral features of a diverse range of ablated meteorite samples with a known composition are presented. We aim to provide a reference spectral dataset to improve our abilities to classify meteoroid composition types from meteor spectra observations. The data were obtained by ablating meteorite samples in high-enthalpy plasma wind tunnel facilities recreating conditions characteristic of low-speed meteors. Near-UV to visible-range (320–800 nm) emission spectra of 22 diverse meteorites captured by a high-resolution Echelle spectrometer were analyzed to identify the characteristic spectral features of individual meteorite groups. The same dataset captured by a lower-resolution meteor spectrograph was applied to compare the meteorite data with meteor spectra observations. Spectral modeling revealed that the emitting meteorite plasma was characterized by temperatures of 3700–4800 K, similar to the main temperature component of meteors. The studied line intensity variations were found to trace the differences in the original meteorite composition and thus can be used to constrain the individual meteorite classes. We demonstrate that meteorite composition types, including ordinary chondrites, carbonaceous chondrites, various achondrites, stony-iron and iron meteorites, can be spectrally distinguished by measuring relative line intensities of Mg I, Fe I, Na I, Cr I, Mn I, Si I, H I, CN, Ni I, and Li I. Additionally, we confirm the effect of the incomplete evaporation of refractory elements Al, Ti, and Ca, and the presence of minor species Co I, Cu I, and V I.

Qualitative Geochemical Analysis of the 2004 Indian Ocean Giant Tsunami Deposits Excavated at Seungko Mulat Located in Aceh Besar of Indonesia Using Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) was employed to characterize the geochemical signatures layer by layer of 2004 Indian Ocean tsunami deposits in Seungko Mulat Village, Aceh Province, Indonesia. In the LIBS experimental setup, a Nd-YAG laser beam is directed towards the deposit samples, and the resulting atomic emission lines from the laser-induced plasma are captured using a spectrometer. Our analysis reveals terrestrial indicators (Fe), heavy metals (Cu, Cr, Co, Cd), and increased emission intensity of Mg, Ca, Al, K, Si, Ba, N, and O in the 2004 Indian Ocean tsunami layers. The emission intensity ratios of several elements in the 2004 Indian Ocean tsunami deposit layers, namely Ca/Ti, Si/Ti, and K/Ti, unveil notable disparities among the elements evaluated. This indicates the possibility of utilizing these ratios as reliable geochemical markers to differentiate the layer by layer of tsunami deposits. LIBS surpasses XRF in detecting nearly all elements simultaneously and identifying both light elements and specific heavy metals (Ba, Cu, Cr, Co, Cd, Pb, Ni, V, W), exceeding XRF's detection capabilities. This study emphasizes the effectiveness of LIBS as an advanced optical technique, offering speed and promise in analyzing layer-by-layer geochemical markers of the 2004 Indian Ocean tsunami deposits in Seungko Mulat Village.

Predicting crystallite size of Mg-Ti-SiC nanocomposites using an adaptive neuro-fuzzy inference system model modified by termite life cycle optimizer

In this study, Mg-Ti-SiC composite powders with varied micron and nano silicon carbide (SiC) particle sizes were fabricated utilizing the ball milling technology at various milling times. The effect of reinforcement particles sizes and milling time on the morphology and microstructure of the magnesium composite powders was characterized. Then, we developed a machine-learning model based on Adaptive Neuro-fuzzy Inference System (ANFIS) modified with termite life cycle optimizer to predict the crystallite size of the produced composites. The average particles size in all composites including micron SiC (µSiC) and nano SiC (nSiC) always decreased with increasing milling time and SiC content, and the most optimal reduction in particle size was achieved after 16 h of milling for both configurations, which were 5.12 µm and 1.96 µm, respectively. Changing reinforcement particle size from micron to nano caused the peak intensities of Mg and Ti more decreased and phases Ti5Si3 and TiC were observed after milling for 16 h in ND composite powder. With increasing milling time in Mg-25 wt% Ti-5 wt% µSiC, the crystallite size decreased from 31 nm to 13.62 nm after 1 h and 32 h milled, respectively. The most optimum reduction in crystallite size occurred in the composite powders including nSiC, in which crystallite size decreased to 13.35 nm. The developed Machine learning model was able to predict the evolution of the crystallite size of the produce d composites with very good accuracy.

A multi-cation responsive Ni(II)-supramolecular metallogel mimics a molecular keypad lock via reversible fluorescence switching.

Synthesis of a bidentate N,O-donor Schiff base fluorescent ligand 5-(diethylamino-2-((4-(diethylamino-2-((4-(diethylamino)phenylimino)ethyl)phenol) (HL) adopting a new preparation procedure and its complexes with Ni(II) (1) and Zn(II) (2) has been illustrated. Structures of HL and 1 have been elucidated using X-ray single crystal analysis. Moreover, HL leads to the formation of a mechanically stable Ni(II)-gel (MG) upon treatment with Ni(NO3)2·6H2O in the presence of triethylamine (TEA) using THF/MeOH (1 : 1) solvents at rt. The gelator HL, complexes 1-2 and MG have been characterized by different spectroscopic and microscopic techniques including NMR (1H & 13C), FT-IR, ESI-MS, SEM, powder-XRD, rheology, UV/vis and fluorescence analysis. Rheological studies suggested good mechanical and thermal stability, whereas SEM analysis reveals a porous earth crust-like morphology of MG. Notably, 1 : 1 complexation between HL and Ni(II) forms a stable gel (MG), whereas 2 : 1 (HL : Ni2+) complexation leads to partial gelation. Formation of the Ni(II)-MG leads to slight "Turn-OFF" fluorescence relative to HL with a limit of detection (LOD) of 7.76 × 10-9 M; however, MG is considered as the "ON" state due to moderate emission. Remarkably, Ni(II)-MG further displayed reversible "ON-OFF-ON" fluorescence switching behavior through detection of Zn2+, Cu2+ and Hg2+. The emission intensity of MG is quenched with Cu2+/Hg2+ but enhances with Zn2+ in 1 : 1 (MG : M2+) stoichiometry. Therefore, MG mimics a sequence dependent molecular keypad lock for Cu2+ (C), Hg2+ (H) and Zn2+ (Z) to give the maximum output. Association and quenching constants were calculated by the Benesi-Hildebrand method, and from the Stern-Volmer plot the LOD was determined to be 4.2 × 10-6 M, 5.8 × 10-6 M and 7.8 × 10-6 M for MG with Zn(II), Cu(II) and Hg(II), respectively. To date, Ni(II) based MGs have been explored only toward electrochemical, thermal and conduction studies; however, the present work demonstrates the fluorescent reversible cation detection behavior of Ni(II)-MG to act as a molecular keypad lock for development of password protection devices.

Investigation on surface morphology and microstructure of double-wire + arc additive manufactured aluminum alloys based on spectral analysis

Double-wire + arc additive manufacturing has gained increasing attention due to the advantage of controlling alloy composition in real time. However, the control mechanisms of microstructure and mechanical properties of high strength aluminum alloys have not been revealed. To solve this problem, in-situ monitoring of double-wire + arc additive manufacturing process were carried out by the spectrograph and a visual sensor. The spectral signal and arc plasma characteristics under different wire feeding rate ratios were systematically studied. Combined with the high-speed photography results of the droplet transfer, it was found that spectral intensities of Mg I 517.26 nm represented abnormally high during the globular transfer process. Surface bulges with the size of about 100 μm were detected. In addition, the microstructure and phase composition of the deposited parts were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results indicated that the variation of electron temperature was consistent with the variation trend of Al2CuMg phase content under different processes. The intensity ratio IRMn/Mg of spectral line Mn I 407.92 nm to Mg I 517.26 nm was proposed to quantitatively measure the degree of phase transformation, which had a better performance than the spectral line intensity and electron temperature. Under the conditions of this research, the phase composition was α(Al) + θ(Al2Cu) + S(Al2CuMg) three-phase when the IRMn/Mg fluctuated around 0.59, and α(Al) + S(Al2CuMg) two-phase produced when the IRMn/Mg fluctuated around 0.35.

Enhanced mechanical properties and formability of hot-rolled Mg–Zn–Mn alloy by Ca and Sm alloying

In order to broaden the application of wrought Mg alloy sheets in the automotive industry, the influence of Ca and Sm alloying on the texture evolution, mechanical properties, and formability of a hot-rolled Mg–2Zn–0.2Mn alloy was investigated by OM, XRD, SEM, EBSD, tensile tests, and Erichsen test. The results showed that the average grain size and basal texture intensity of Mg–2Zn–0.2Mn alloys were remarkably decreased after Ca and Sm additions. 0.64 wt.% Ca or 0.48 wt.% Sm addition significantly increased the tensile strength, ductility and formability. Moreover, the synergetic addition of Sm and Ca improved the ductility and formability of Mg–2Zn–0.2Mn alloy, which was due to the change of Ca distribution and further reduction of the size of Ca-containing particles by Sm addition. The results provided a possibility of replacing RE elements with Ca and Sm in Mg alloys which bring about outstanding mechanical properties and formability.

Structure of single KL0–, double KL1–, and triple KL2 − ionization in Mg, Al, and Si targets induced by photons, and their absorption spectra

We investigated experimentally and theoretically x-ray properties of Mg, Al and Si to assess for new reliable x-ray useful quantities. We measured the KL0– diagram, and KL1– and KL2– satellite lines in Mg, Al, and Si, ionized by photon excitation, using a high-resolution anti-parallel double-crystal x-ray spectrometer. Their energy values, full width at half maxima (FWHM), and relative intensities are obtained by the multiple fitting methods and compared with those reported by other excitation processes. It was found that the relative intensity of Mg and Si KL1 and KL2 satellite lines to the KL0 diagram lines depend on the method used to produce the K hole. The evidence of a new transition between Kα3 and Kα4 in Mg, Al, and S KL1 satellite lines is suggested. These x-ray diagram and satellite lines were investigated theoretically and we found that Mg Kα1,2 diagram lines with hidden satellites are especially in very good agreement with the corresponding experimental ones. Moreover, we also determined the mass attenuation coefficients in a wide energy range covering the K-absorption edge, including a detailed evaluation of the associated uncertainties. From the absorption spectra of Mg and Al, the cross sections of the multi-electron transition processes were estimated and match the theoretical values.

Compositional control and high-temperature phase stability of plasma-sprayed Ba(Mg1/3Ta2/3)O3 coatings

The Ba(Mg 1/3 Ta 2/3 )O 3 (BMT) ceramic is considered a promising material for high-performance thermal barrier coating (TBC), due to the ultra-high melting point and excellent thermophysical properties . However, the preferential evaporation of Mg from BMT during plasma spraying causes the composition in deposited coatings to deviate from the standard stoichiometry , resulting in the formation of undesirable barium tantalite. These impurities would accelerate the cracking and failure of BMT with low fracture toughness during thermal shock , which greatly limits the application of BMT coatings. In this study, the evaporation of Mg, and the evolutionary characteristics of the composition and microstructure of BMT particle in the plasma spray process were investigated. The relationship between the melting conditions of BMT particles and the composition and microstructure of the coatings was analyzed. The compositional controls, and the high-temperature phase stability of plasma-sprayed BMT coatings were studied and characterized. The results indicate that the evaporation intensity of Mg was strongly affected by the melting conditions of the BMT particles in the plasma jet . The particles with a higher degree of melting had a greater evaporation intensity of Mg, owing to the higher heat transfer and element diffusion rate, and more impurity phases formed in the deposited coating. The nonuniformity of Mg evaporation in BMT particle could lead to composition segregation, promoting the formation of the impurity phases during particle solidification, and ultimately affect the composition uniformity of the coating. By employing the powder with large particle sizes and adjusting the spray parameters to reduce the energy of plasma jet under the premise of ensuring the coating deposition quality, the evaporation intensity of Mg and the content of impurity phase could be significantly restrained, and the high-temperature phase stability of the coatings could be greatly improved compared to the original unmodified BMT coatings. • Evaporation behavior of Mg in plasma sprayed Ba(Mg 1/3 Ta 2/3 )O 3 (BMT) was investigated. • Relationship between the melting conditions of BMT particles and the characteristics of the coating was analyzed. • The composition of BMT coating was controlled by adjusting the powder size and spraying parameters. • Significant improvement in high-temperature phase stability of the BMT coatings was achieved.

EFFECT OF 1% Nа ON THE INTENSITY DISTRIBUTION OF THE SAMPLE ATOMS IN NITROGEN MICROWAVE PLASMA WITH AXIAL AND RADIAL OBSERVATION

The effect of 1% Na with axial and radial observation of microwave plasma on the analytical characteristics of the optical spectrometer “Grand-Microwave” is investigated. The presence of 1% Na in the analyzed sample leads to a decrease in the intensities of spectral lines with energies of 6 - 14 eV with the axial observation method by 8 - 50 times, and with the radial method by 2,5 - 8 times, depending on the observation area. The intensity of lines with energies of 1.6 - 6 eV increases by up to 20 times in the axial view, and by 4 to 6 times in the radial view. In the presence of Na, the ratio of the intensities of Mg (II) 280 nm and Mg (I) 285 nm decreases by 2 orders of magnitude for both observation methods, the temperature at the periphery of the axial view of the plasma decreases by 1300 K, and the temperature at the lower boundary of the radial view decreases by 2300 K. The method and scope of the review for the analysis of 25 chemical elements with minimal matrix influences Na and the efficiency of using the recommended areas was evaluated.

XGBoost-based on-line prediction of seam tensile strength for Al-Li alloy in laser welding: Experiment study and modelling

• A new XGBoost prediction model for real-time SSC prediction in laser welding. • 68.6 % increase rate of the new model from 0.2947 to 0.9383. • Li I at 395.09 nm shows the highest importance followed by Al I at 669.84 nm, Mg I at 518.4 nm and Ar I. • A good linear and positive correlation between the spectrum intensity of Mg I (517.27 nm) and seam strength coefficient. This paper studies the regression prediction of laser welding seam strength of aluminum-lithium alloy used in the rocket storage tank by means of the optical spectrum and extreme gradient boosting decision tree (XGBoost). First, the relationship between the spectrum intensity and the seam strength coefficient is thoroughly investigated through parameters changing experiments using the developed monitoring system of the optical spectrum. Then, the importance of the metal line spectrum, including Al I, Li I, and Mg I, is quantitatively evaluated, and good complementarity between the Random Fores(RF)t and Principal Component Analysis(PCA) is demonstrated. Finally, a novel regression model, e.g., RFPCA-XGBoost is proposed and is compared with other different feature selection methods, tree-based ensemble learning models and grid search parameters optimization, and the comparison results show that among all the methods, the proposed model has the best performance regarding the R2 value, achieving the R2 value of 0.9383.

Improvement in electrochemical corrosion resistance of Mg–Al–Zn alloy by 250 keV carbon ions irradiation

Mg–Al–Zn alloy (AZ91D) was irradiated with carbon ions at different doses (1 × 1013, 5 × 1013, 1 × 1014, 5 × 1014 and 1 × 1015 ions cm−2) by using Pelletron Accelerator. Ion energy was kept constant at 250 keV for all the irradiated samples. The range of carbon ions inside the alloy was found to be 0.67 μm. X-ray diffraction results indicated that the carbon ions irradiation of Mg alloy increases the intensity of Mg (002) plane. The average crystallite size of Mg alloy was decreased at 1 × 1013 ions cm−2 whereas an increase in the crystallite size was observed by further increasing the ion dose. The FTIR data indicated C–H, C–O, C=O and C-C vibrational modes in the irradiated samples. The electrochemical corrosion of Mg–Al–Zn alloy was investigated through potentiondynamic polarization tests in 0.9% NaCl solution. The open circuit potential (OCP) did not change at lower ion doses (up to 1 × 1014 ions cm−2), however, the OCP became more positive as the ion dose was increased to 1 × 1015 ions cm−2. Similarly, corrosion current density and corrosion rate were significantly decreased after carbon irradiation at 1 × 1015 ions cm−2. The SEM results revealed severe surface pitting of the unirradiated alloy that was reduced after the carbon ions irradiation.

Neutron Activation Analysis as a tool to Determine Concentration of Selected Metals in Table Salt Mined from Benya Lagoon, Ghana

This project was funded by The Directorate of Research, Innovation and Consultancy (DRIC) and the Management of the University of Cape Coast. It was sponsored as a Group-led Research involving researchers from the Department of Physics during the third call for proposals for Research Support Grants (RSGs) in 2018 Abstract Table salt is essential for life and if it contains metal impurities, it can affect the people that consume it. The Komenda Edina Eguafo Abrem municipality makes salt by evaporating brine from the Benya Lagoon. Benya lagoon is a lagoon known to be polluted due to various anthropogenic activities within its environs. The concentration of eight metals, Arsenic (As), Cadmium (Cd), Manganese (Mn) Lead (Pb), Aluminium (Al), Copper (Cu), Magnesium (Mg), and Vanadium (V) have been determined in salt mined using water from the Benya lagoon. Salt samples were selected from five fixed-sampling stations and the concentrations of the metals determined using Neutron Activation Analysis. The ranges of the measured concentrations in the salts are as follows: 161.04-632.63 mg/kg for Al, 0.001-0.004 mg/kg for As, 1.50-2.70 mg/kg for Mg, 49.14-3883.00 mg/kg for Mg, 17.24-110.96 mg/kg for Mn, and 2.85-7.10 mg/kg for V. An assessment according to the metal concentration marked Mg as the most abundant, whiles Cd and Pb the least being 0.001 mg/kg at all the five stations. Principal Component Analysis also established Mg to be the most abundant metal, and used to identify two major clusters; Group 1 (stations 4 and 5) and Group 2 (stations 1, 2 and 3). Group 2 recorded higher intensities of Mg. Using Pearson's correlation coefficient, significant correlations were drawn between Al and Mg (r = - 0.862), Mg and Mn (r = 0.863) and Mn and V (r = 0.735), indicating the same or similar source inputs for each pair. Comparison with Codex Standard for Food Grade Salt showed that concentration values recorded for Al, Mg and Mn were above recommended limits. The contamination factor (C F ) and degree of contamination (C D ) confirmed this level of contamination for Al, Mg and Mn for all the five Stations, with Station 2 recording the highest Degree of Contamination. the least and corroborated salt from station 2 as most contaminated considering the combined toxicity at each station. Using an average daily salt intake of 6,000 mg, the mean daily intake of the elements when one consumes salt mined from the Benya lagoon was found to be above each element’s Upper Tolerable Limit of its Recommended Dietary Allowable for the various Life Stage Groups. The associated Hazard Index suggests the probability of adverse effects when consumed. High standard deviation values for Al and Mn indicated the non-uniform spatial distribution of the individual metal contaminates at the various stations. Keywords: Benya Lagoon; salt; heavy metal; contamination factor; degree of contamination, neutron activation analysis; recommended daily allowance, GHARR-1 DOI : 10.7176/CMR/11-8-06 Publication date :October 31 st 2019

Spectral diagnosis of wire arc additive manufacturing of Al alloys

Online nondestructive testing for quality control is a critical direction for research in additive manufacturing in the future. In this study, for the first time, optical emission spectroscopy was employed to probe the arc characteristics in the wire arc additive manufacturing (WAAM) of an Al alloy and to detect its structural features. The arc characteristics, such as spectral intensity, electron density, and electron temperature, were calculated based on the atomic emission spectral lines. The resulting structural features of the deposited layers, namely the forming width, composition, grain size, and porosity defects, were analyzed, and a correlation between the arc characteristics and the structural features was proposed. The arc cathode size, which changed with the number of deposited layers, controlled the arc energy distribution. Hence, the forming width had an approximately linear relation with the spectral intensity of Mg (a constituent of the alloy used for the wire feed) and the electron density. The porosity in the alloy was observed to be caused by H, which was a dominant pollutant in the process. Furthermore, the correlation between the porosity and H spectral intensity was observed to be approximately linear. However, no significant correlation between the grain size and the spectrum was noticeable. The results from this study establish the applicability of spectral diagnosis of the forming size and the porosity in WAAM.

Feasibility of Quantitative Analysis of Magnesium and Calcium in Edible Salts Using a Simple Laser-Induced Breakdown Spectroscopy Device.

Feasibility of a simple laser-induced breakdown spectroscopy (LIBS) device has been investigated for the analysis of Mg and Ca in edible salts. The LIBS spectrometer was assembled with a compact low-power diode-pumped solid-state laser (DPSSL) and a non-gated low-resolution handheld spectrometer. A simple sampling process was employed for on-site application. A piece of filter paper was dipped in the aqueous solution of a sample salt and dried for analysis using LIBS. Maintaining the sample surface height at the optimum position was critical to generate plasmas persistently due to the low pulse energy of the DPSSL. The varying height of the filter paper surface was monitored and compensated, while the sample stage was translated to collect spectra from different positions. The variation of line intensities of Mg and Ca could be attributed to the inhomogeneous distribution of dry residues. To correct this, the peak that consists of the Na(I) and C(II) lines at 568 nm was employed as a reference signal for intensity normalization of the analyte Mg(II) and Ca(II) lines. For edible salt products, the normalized Mg(II) and Ca(II) line intensities could be well correlated with the concentrations of Mg and Ca determined using inductively coupled plasma optical emission spectroscopy. Our results indicate that a simple LIBS device in combination with the simple sampling method is promising as an on-site salt quality assessment methodology.

Statistical analysis of UV spectra of a quiescent prominence observed by IRIS

Context. The paper analyzes the structure and dynamics of a quiescent prominence that occurred on October 22, 2013 and was observed by several instruments including the Interface Region Imaging Spectrograph (IRIS). Aims. We aim to determine the physical characteristics of the observed prominence using Mg II k and h (2796 and 2803 Å), C II (1334 and 1336 Å), and Si IV (1394 Å) lines observed by IRIS. In addition we study the dynamical behavior of the prominence. Methods. We employed the one-dimensional non-LTE (departures from the local thermodynamic equilibrium – LTE) modeling of Mg II lines assuming static isothermal-isobaric slabs. We selected a large grid of models with realistic input parameters expected for quiescent prominences (temperature, gas pressure, effective thickness, microturbulent velocity, height above the solar surface) and computed synthetic Mg II lines. The method of Scargle periodograms was used to detect possible prominence oscillations. Results. We analyzed 2160 points of the observed prominence in five different sections along the slit averaged over ten pixels due to low signal to noise ratio in the C II and Si IV lines. We computed the integrated intensity for all studied lines, while the central intensity and reversal ratio was determined only for both Mg II and C II 1334 lines. We plotted several correlations: time evolution of the integrated intensities and central intensities, scatter plots between all combinations of line integrated intensities, and reversal ratio as a function of integrated intensity. We also compared Mg II observations with the models. Results show that more than two-thirds of Mg II profiles and about one-half of C II 1334 profiles are reversed. Profiles of Si IV are generally unreversed. The Mg II and C II lines are optically thick, while the Si IV line is optically thin. Conclusions. The studied prominence shows no global oscillations in the Mg II and C II lines. Therefore, the observed time variations are caused by random motions of fine structures with velocities up to 10 km s−1. The observed average ratio of Mg II k to Mg II h line intensities can be used to determine the prominence’s characteristic temperature. Certain disagreements between observed and synthetic line intensities of Mg II lines point to the necessity of using more complex two-dimensional multi-thread modeling in the future.

Application of Laser Induced Breakdown Spectroscopy in Early Detection of Red Palm Weevil: (Rhynchophorus ferrugineus) Infestation in Date Palm

The Kingdom of Saudi Arabia is one of the leading date producing countries. Unfortunately, this important fruit crop is under great threat from the red palm weevil (RPW) (Rhynchophorus ferrugineus), which is a highly invasive pest. Several techniques, including visual inspection, acoustic sensors, sniffer dogs, and pheromone traps have been tried to detect the early stages of a RPW infestation; however, each method has suffered certain logistical and implementation issues. We have applied laser induced breakdown spectroscopy (LIBS) for the early detection of RPW infestation. Through the analysis of the observed LIBS spectra of different infested and healthy samples, we have found presence of Ca, Mg, Na, C, K elements and OH, CN molecules. The spectra also reveal that with the population growth of the pest, the intensity of Mg and Ca atomic lines in LIBS spectra increases rapidly. Similar behavior is observed in the molecular lines of LIBS spectra. The obtained results indicate that the LIBS technique can be used for the early detection of RPW infestation without damaging the date palms.

Straightforward way to enhance robustness in ultrasonic nebulization-axial view inductively coupled plasma optical emission spectrometry via an additional N2 gas stream

In the present study a low flow of N2 is mixed with the aerosol produced by ultrasonic nebulization (USN) prior analysis using inductively coupled plasma optical emission spectrometry (ICP OES). The foreign gas is added for improving plasma characteristics in axially-viewed ICP. By computing the Mg ionic to atomic ratio (plasma robustness) it was concluded that N2 dissociates closer to the load coil when USN is used as sample introduction system. The maximum emission intensity of Mg(II) for pneumatic nebulization (PN) was observed at 11mm from the load coil while it was 8mm for USN, indicating earlier aerosol desolvation, atomization and excitation processes in the ICP. Emission profiles of Ar(I) 415.861nm, Ba(II) 486.601nm and Ba(II) 233.527nm indicated that metastable Ar species are overpopulated in the ICP under the N2 flow. Copper and manganese ionic lines with energy close to 16eV (Ar ionization) were monitored to evaluate spatially dependent charge-transfer reaction along the ICP axis in the presence and absence of the N2 flow. The Cu(II) signal profiles indicated abundance of Ar+ species at low distances from the load coil when N2 was added. On the other hand, differences were not observed at longer distances from the load coil for both plasmas (mixed-gas and pure Ar-ICP). The calculated limits of detection (LODs) for both plasmas had the same order of magnitude. Analysis of certified reference samples demonstrated that the accuracy was preserved by adding the low flow of N2. It was concluded that adding a low flow of N2 to the aerosol produced by USN is a simple way to increase plasma robustness, which is usually lower than that achieved using conventional PN.

The Spectral Emission Characteristics of Laser Induced Plasma on Tea Samples**supported by National Natural Science Foundation of China (No. 61205149), the Scientific and Technological Talents Training Project of Chongqing, China (No. CSTC2013kjrc-qnrc40002), the Scientific and Technological Project of Nan'an District (2011) and the Visiting Scholarship of State Key Laboratory of Power Transmission Equipment & System Security and New Technology at

Laser induced breakdown spectroscopy (LIBS) provides a useful technique for food security as well as determining nutrition contents. In this paper, optical emission studies of laser induced plasma on commercial tea samples were carried out. The spectral intensities of Mg, Mn, Ca, Al, C and CN vibration bands varying with laser energy and the detection delay time of an intensified charge coupled device were studied. In addition, the relative concentrations of six microelements, i.e., Mg, Mn, Ca, Al, Na and K, were analyzed semi-quantitatively as well as H, for four kinds of tea samples. Moreover, the plasma parameters were explored, including electron temperature and electron number density. The electron temperature and electron number density were around 11000 K and 1017 cm−3, respectively. The results show that it is reasonable to consider the LIBS technique as a new method for analyzing the compositions of tea leaf samples.

Study on the assemblage of Y and Gd on microstructure and mechanical properties of hot extruded Mg–Al–Zn alloy

The microstructure and the mechanical properties of hot extruded Mg–Al–Zn alloy with the addition of Y and Gd were thoroughly investigated under two different conditions with and without aging treatments. The results showed that dynamic precipitation of Mg17Al12 phase occurred during hot deformation, and only Al2(Y,Gd) phase (no Al8Mn5 phase which was a common phase in Mg–Al–Zn alloy) was observed in the alloy. In addition, the basal texture intensity of Mg–Al–Zn alloy was weakened, which probably originates from both the promotion of nonbasal slip due to the addition of Y and Gd and the well-known particle-stimulated nucleation (PSN). Within the aged sample, there are less lamellar discontinuous precipitations (DPs), more globular DPs, and thinner continuous precipitation (CP) laths after Y and Gd addition. A new crystallographic orientation relationship (OR) between the β-Mg17Al12 precipitate and the α-Mg matrix was identified as (0001)m//(110)p and [011¯0]m//[1¯13]p. Finally, both tensile and compressive strengths are improved by the addition of Y and Gd, with the tension–compression yield asymmetry being reduced.