Effect Of Sample Temperature Research Articles

Effect of sample temperature and laser ablation angle on optical emission and acoustic signals from laser-induced zirconium plasma

A fiber-coupled, acoustic-wave-assisted (AW) microchip laser-induced breakdown spectroscopy (mLIBS) system was developed to analyze the elemental composition and surface imaging. In this study, we measured the dependence of sample temperature and laser ablation angle (LAA) on the laser-induced plasma–optical emission (LIP–OE) and LIP–acoustic signal (LIP–AS). The intensity of the LIP–OE and ablated mass at three different temperatures and eight different LAAs were estimated using a zirconium sample. Simultaneously, we investigated the LIP–AS amplitude, propagation speed, and shape by synchronizing the AW-mLIBS system with a high-speed camera. The results revealed that the LIP–OE increases with increasing temperature and is unaffected by LAA up to 40° because the amount of the ablated mass was similar to the plasma. Additionally, no considerable variation in plasma temperature was obtained using the Boltzmann method over the sample temperature. However, the propagation speed of the LIP–AS differs with temperature but has marginal angular dependence because the LIP–AS propagates as semispherical. Furthermore, no considerable changes were observed in the LIP–AS amplitude up to 100°C, and the LAA showed a similar tendency to that of the LIP–OE.

The influence of the content of phosphates in water on the propagation speed of ultrasonic waves.

The phosphate content of a test sample is one of the indicators of the trophic status of the test water. In this work, an attempt was made to use a non-destructive ultrasonic technique to determine this parameter. For this purpose, a specially prepared measuring station was used, on which distilled water samples with different phosphate contents were tested. Specially prepared samples contained 0, 20, 40, 60, 80 and 100 kg/m3 of phosphates. In addition, tests were carried out on the effect of sample temperature on the values of the characteristic parameter of the wave, in the range from 12 to 30 oC. All tests were carried out using two ultrasonic heads with a wave frequency of 2 MHz. The ultrasonic wave parameter analysed in the study was the propagation speed of the ultrasonic wave. The results obtained indicate that the ultrasonic method is useful for non-destructive evaluation of phosphate content in the sample. Additionally, they show a large influence of the sample temperature on the results read.

Effect of Sample Temperature on Spectra of AlO Molecules in Femtosecond Laser-Induced Al Plasma

Effect of Sample Temperature on Spectra of AlO Molecules in Femtosecond Laser-Induced Al Plasma

Effect of sample temperature on femtosecond laser ablation of copper

We conduct an experimental study supported by theoretical analysis of single laser ablating copper to investigate the interactions between laser and material at different sample temperatures, and predict the changes of ablation morphology and lattice temperature. For investigating the effect of sample temperature on femtosecond laser processing, we conduct experiments on and simulate the thermal behavior of femtosecond laser irradiating copper by using a two-temperature model. The simulation results show that both electron peak temperature and the relaxation time needed to reach equilibrium increase as initial sample temperature rises. When the sample temperature rises from 300 K to 600 K, the maximum lattice temperature of the copper surface increases by about 6500 K under femtosecond laser irradiation, and the ablation depth increases by 20%. The simulated ablation depths follow the same general trend as the experimental values. This work provides some theoretical basis and technical support for developing femtosecond laser processing in the field of metal materials.

Effect of sample temperature on laser-induced plasma of silicone rubber

Silicone rubber in power transmission and transformation equipment is subjected to considerable temperature changes under different application environment conditions and in different operational states. In tropical areas and the Turpan region of China, surface temperatures of silicone rubber insulators may reach or exceed 70°C. During in situ testing of silicone rubber, the spectral signal may fluctuate or even be distorted when the temperature changes, and consequently, the accuracy of the analysis may be affected. Therefore, we performed a LIBS-based investigation into the dependence of the spectral signal of rubber silicone on the sample temperature. Using high-temperature vulcanized silicone rubber as the experimental material, we determined the trends in spectral line intensity for different elements, plasma temperature, and electron density with temperature when the sample temperature was increased from 25°C to 310°C. The results indicated that the intensities of the Al I 394.40 nm, Al I 396.15 nm, and Si I 390.55 nm lines in the LIBS spectra underwent a gradual decrease as the temperature was increased, whereas the intensity of the Al I 309.27 nm spectral line was essentially stable. However, the spectral line intensity, plasma temperature, and electron density all exhibited a spike at approximately 260°C, which occurred because of the decomposition of aluminum hydroxide. The results of the present study should prove to be of significance in further increasing the accuracy of LIBS analysis as applied to silicone rubber surface monitoring in high-temperature environments.

The Effect of Sample Temperature on Sensory Quality of Caseless Sausages — cevap

The Effect of Sample Temperature on Sensory Quality of Caseless Sausages — cevap

Sample Temperature Affects Measurement of Nitrate with a Rapid Analysis Ion Selective Electrode System Used for N Management of Vegetable Crops

The practical value of portable hand-held ion selective electrode sensors (ISE) for on-farm [NO3−] measurement to assist with crop N management of vegetable crops has been demonstrated in numerous previous studies. They provide rapid, in-situ measurement of the nitrate concentration ([NO3−]) in nutrient and soil solutions, and in petiole sap. Sample temperatures, for on-farm measurements, vary appreciably. This study evaluated the effects of sample temperature on [NO3−] measurement using two different models of a commonly used, commercially available, portable ISE meter. The temperatures (5, 10, 15, 20, and 25 °C) examined were in the range likely to be encountered in practical on-farm work. Aqueous solutions of 6, 12, and 18 mmol NO3− L−1 were prepared from KNO3, Ca(NO3)2 and NaNO3. [NO3−] was measured in three replicate samples of each of the three concentrations, made from each NO3− compound, at each temperature. The results consistently and clearly demonstrated a strong negative linear relationship between temperature-induced errors and sample temperatures. The temperature-induced error was considerable for cooled samples, being +50% at 5 °C and +31% at 10 °C. At sample temperatures of 17–20 °C, the temperature effects were minimal. Above this range, the temperature effect caused underestimation. At 25 °C, the temperature-induced error was −24%. These results show that care must be taken to ensure that sample temperatures do not erroneously affect the measurement of [NO3−] with ISE meters. Particular care needs to be taken with both refrigerated and warmer samples.

Study on the Effect of Sample Temperature on the Uniaxial Compressive Mechanical Properties of the Brain Tissue.

Craniocerebral injury has been a research focus in the field of injury biomechanics. Although experimental endeavors have made certain progress in characterizing the material behavior of the brain, the temperature dependency of brain mechanics appears to be inconclusive thus far. To partially address this knowledge gap, the current study measured the brain material behavior via unconstrained uniaxial compression tests under low strain rate (0.0083 s−1) and high strain rate (0.83 s−1) at four different sample temperatures (13°C, 20°C, 27°C, and 37°C). Each group has 9~12 samples. One-way analysis of variance method was used to study the influence of sample temperature on engineering stress. The results show that the effect of sample temperature on the mechanical properties of brain tissue is significant under the high strain rate, especially at low temperature (13°C), in which the hardening of the brain tissue is very obvious. At the low strain rate, no temperature dependency of brain mechanics is noted. Therefore, the current results highlight that the temperature of the brain sample should be ensured to be in accordance with the living subject when studying the biomechanical response of living tissue.

DESIGN OF EXPERIMENT (DOE) BASED STUDY OF FACTORS AFFECTING UV ABSORPTION OF HYDROCHLOROTHIAZIDE

Present work was carried out to evaluate the effect of process variables on the UV absorbance of hydrochlorothiazide. The effect of three variables namely such as sample temperature, nature of the solvent and sample volume on UV absorption was studied by using the design of experiments (DOE) approach. Central Composite Design (CCD) was applied to investigate the effect of sample temperature (A) variation in the range of 15 °C - 45 °C, nature of the solvent (B) viz. ethanol, methanol, and 4 % sodium hydroxide and sample volume (C) in the range of 1.5 mL to 2 mL on the UV absorbance of Hydrochlorothiazide. Each of the parameters was varied at three different levels (-1, 0, 1) and twenty suggested experimental runs were conducted with six central points. The data was then analyzed for model fitting and finding how each of the variables affected the response by using ANOVA. The three variables under study were found to have a moderate effect on the UV absorbance, as expected based on theoretical concepts. However, the influence was found to be statistically insignificant as the P value for the individual parameter was found to be greater than 0.05. Further, the P value was less than 0.05 for the squares of temperature, solvent, and combination of solvent and volume for UV absorbance of hydrochlorothiazide, implying that these factors have a statistically significant bearing on UV absorbance. Results showed that out of the three parameters under study, the temperature of the sample affected the absorbance of hydrochlorothiazide the most.

Comparison of sample temperature effect on femtosecond and nanosecond laser-induced breakdown spectroscopy

In this paper, we investigated the emission spectra of plasmas produced from femtosecond and nanosecond laser ablations at different target temperatures in air. A brass was selected as ablated target of the experiment. The results indicated that spectral emission intensity and plasma temperature showed similar trend for femtosecond and nanosecond lasers, and the two parameters were improved by increasing the sample temperature in both cases. Moreover, the temperature of nanosecond laser-excited plasma was higher compared with that of femtosecond laser-excited plasma, and the increase of the plasma temperature in the case of nanosecond laser was more evident. In addition, there was a significant difference in electron density between femtosecond and nanosecond laser-induced plasmas. The electron density for femtosecond laser decreased with increasing the target temperature, while for nanosecond laser, the electron density was almost unchanged at different sample temperatures.

Reliability of 3 Urine Specific Gravity Meters for Measuring Brix and Urine Solutions at Different Temperatures.

Urine specific gravity (USG) should be measured at room temperature (20°C), but the temperature of the sample is not always considered. To evaluate the effect of sample temperature on the measurement accuracy of a digital refractometer (DIG), manual optical refractometer (MAN), and hydrometer (HYD). Descriptive laboratory study. Urine specific gravity. Experiment 1 (24 Brix (°Bx) samples) showed that measurements via the DIG and MAN did not differ from the reference, but HYD provided lower or inconsistent values compared with °Bx and was highly correlated with °Bx solutions (r, > = 0.89). The overall diagnostic ability of elevated USG cut-off values (≥1.020, ≥1.025, ≥1.030) was high for all tools (area under the curve >0.92). Misclassification of samples increased from 0 to 2 at 1.020 to 1 to 3 samples at cutoffs of 1.025 and 1.030 USG. Bland-Altman analysis showed that the DIG 5°C underreported slightly without reporting bias (r = -0.344, P = .13); all other plots for the DIG, MAN, and HYD showed considerably larger underreporting at higher concentrations (r = -0.21 to -0.97 with P >.02) at all temperatures. The outcomes of experiment 2 (33 fresh urine samples) using DIG 20°C as the standard demonstrated only negligible differences between the DIG and MAN at all temperatures but larger differences using the HYD. All tools showed reporting bias compared with the °Bx solutions, which can affect the classification of low and high urine concentration at higher USG cutoff values, especially with a sample temperature of 37°C.

Measurement of the glass transition temperature of an epoxy resin using principal components of Raman spectra

Many fibre reinforced polymer (FRP) composite manufacturing processes benefit from the ability to monitor the polymerisation of the resin constituent, either for process control or quality assurance purposes. Whilst most available resin monitoring systems achieve this by measuring the percentage conversion of reactants, measurement of the corresponding glass transition temperature, Tg, is often more informative. The ability to measure Tg directly from spectra acquired by Raman spectroscopy, using principal components analysis, has been demonstrated here for an amine-cured epoxy resin system.A regression model was generated using principal components identified from spectra acquired of cured resin samples produced at a range of isothermal conditions, regressed against corresponding Tg values measured by dynamic scanning calorimetry (DSC). Spectra acquired during the cool-down period following completion of one trial were incorporated into the calibration dataset to ensure effects of sample temperature were accounted for in the principal components analysis (PCA). Measurements obtained with the resultant model, generated using 5 principal components accounting for 97% of the variance in the calibration dataset, were shown to agree well with final sample DSC measurements from in situ cure trials, differing by ≤ 0.6 °C, and exhibiting negligible sensitivity to sample temperature.The results demonstrate the potential of Raman spectroscopy coupled with PCA as a non-contact cure monitoring technique, able to directly measure Tg of a thermosetting epoxy resin system typical of those used in FRP composites manufacture, independent of sample temperature.

Effect of sample temperature on spectroscopic investigation of laser-induced aluminum and copper plasma

In this work, the influence of samples temperature and laser energy on the optical emission spectra and plasma parameters of laser-induced breakdown spectroscopy for aluminum and copper metallic target is investigated. The samples are uniformly cooled down to −70 °C and heated up to 200 °C by an external liquid nitrogen and ceramic heater, respectively. The plasma formed is generated by ablating the surface targets using Nd:YAG laser with laser energies of 100 mJ, 200 mJ and 300 mJ. The emission spectra at ambient atmospheric pressure are recorded using HR4000 spectrometer. From these spectra, plasma temperatures and electron densities are determined by using Boltzmann plot and Stark broadening methods, respectively. A significant increase in the peak intensity of spectral lines is observed with increase in the laser energy as well as sample temperature for both elements. Both of these parameters have shown a clear influence on dynamics of laser-induced plasma for each species. In brief, both laser energy and sample temperature affect the emission intensity, temperature and density of the laser-induced plasma generated from aluminum and copper samples.

Sample Temperature Effect on Steel Measurement Using SP-LIBS and Collinear Long-short DP-LIBS

Laser induced breakdown spectroscopy (LIBS) has been investigated as a potential multi-element quantitative analysis tool for the quality control of on-line steel production. This research investigated influence of sample temperature on steel sample measurement using collinear long-short dual-pulse LIBS (long-short DP-LIBS) and single-pulse LIBS (SP-LIBS). The standard steel sample has been uniformly heated in a muffle furnace from 20°C to 700°C. The experimental results show that sample temperature has significantly effect on measurement result using SP-LIBS. However, long-short DP-LIBS can effectively reduce the sample temperature effect on measurement result. The detection characteristics of long-short DP-LIBS and SP-LIBS were compared using the intensity ratio of I Mn 404.136 nm/I Fe 400.524 nm and I Fe 402.187 nm/I Fe 400.524 nm under different delay time and different sample temperature conditions. The signal intensity and plasma temperature can be maintained higher and more stable for a period of time and at different sample temperature by long-short DP-LIBS with smaller error bar compared with that of SP-LIBS, which indicated long-short DP-LIBS has better measurement repeatability than SP-LIBS. The plasma temperature correction method was applied to compare the detection features of long-short DP-LIBS and SP-LIBS. The signal stability of long-short DP-LIBS measurement was improved significantly at different sample temperature with plasma temperature correction. These results demonstrated that the effect of sample temperature can be reduced using long-short DP-LIBS method to improve the on-line detection capability for steel measurement in complex environment.

Studies on accelerated hydrogen isotopes permeation through plasma-facing components of fusion reactors

Experiments on deuterium (D) plasma-driven permeation through plasma-facing components (PFCs) mock-up have been performed in a linear plasma facility PREFACE. The effects of sample temperature, ion incident energy and surface conditions on the permeation behavior have been investigated. An 8 mm thick W armor tile with gaps is installed on membranes made by structural materials to simulate the monoblock type of PFC. CuCrZr alloy and CLF-1 steel membranes are tested at 500 K–750 K. Compared with gas-driven permeation cases, D permeation flux increases dramatically when the plasma is ignited, indicating that the energetic particles could pass through the gaps and result in enhanced permeation flux. The steady state D permeation flux increases with the increase of mock-up temperature, but the sample bias effects (i.e. incident energy effects) are not significant. PICS2 code calculations confirm the thickness of the sheath is comparable with the gap width under the plasma discharge conditions in PREFACE, suggesting that most of the incident ions into the gaps could not reach the bottom of the gaps.

Effect of sample temperature on radiation characteristics of nanosecond laser-induced soil plasma

An Nd:YAG single pulse nanosecond laser of 532 nm wavelength with an 8 ns pulse width was projected on the soil samples collected from the campus of Bengbu College under 1 standard atmospheric pressure. Laser-induced breakdown spectroscopy at different sample temperatures was achieved. The intensity and signal-to-noise ratio (SNR) changes of dif­ferent characteristic spectral lines could be analyzed when the sample temperature changes. The evolution of plasma electron temperature and electron density with the sample temper­ature was analyzed through Boltzmann oblique line method and Stark broadening method. The cause of the radiation enhancement of laser-induced metal plasma was discussed. Ex­perimental results demonstrated that the spectral intensity, SNR, the electron temperature and electron density of plasma are positively related to the sample temperature, and reach saturation at 100 °C.

Vacuum-assisted headspace sorptive extraction: Theoretical considerations and proof-of-concept extraction of polycyclic aromatic hydrocarbons from water samples

The use of a thick sorbent coating in headspace sorptive extraction (HSSE) increases the amount of analytes extracted at equilibrium as well as the time needed to reach it. In this work we propose HSSE sampling under vacuum conditions to reduce equilibration times. A theoretical model is presented that describes the pressure dependence of the so-called vacuum-assisted HSSE (Vac-HSSE) method, and predicts the reduction in equilibration times when lowering the sampling pressure. We take advantage of the theoretical formulation to reach some general conclusions for HSSE on the relationship between the physical characteristics of the stir bar, uptake rates and equilibration times. The theoretical predictions were experimentally verified using water solutions spiked with naphthalene, acenaphthene and fluoranthene as model compounds. The effects of sampling temperature and extraction time under vacuum and regular pressure conditions were thoroughly investigated. The positive combined effect of heating the sample under low sampling pressure pointed that high humidity did not affect the performance of the extraction phase; an effect commonly recorded in headspace solid-phase microextraction. The extraction time profiles built at 25 and 55 °C visualized the substantial improvement in extraction kinetics with Vac-HSSE compared to the regular HSSE method. The results on naphthalene (assumed to evaporate relatively fast from the water sample) provided evidence that at 1 atm gas-sided resistance limited analyte uptake by the stir-bar and that this limitation could be effectively reduced by adopting the vacuum sampling approach. The accelerations of acenaphthene and fluoranthene suggested that gas-phase constraints limited both the evaporation and analyte uptake processes. Independent method optimization of HSSE under each pressure condition yielded a shorter sampling time for Vac-HSSE compared to the regular HSSE procedure (30 min vs. 60 min respectively). The analytical performances of the two optimized methods were evaluated and it was concluded that Vac-HSSE was performing similar (naphthalene and acenaphthene) or better (fluoranthene) than regular HSSE in half the sampling time needed.

Effect of sample temperature on time-resolved laser-induced breakdown spectroscopy

Increasing sample temperature is an effective method for improving emission intensity of laser-induced breakdown spectroscopy (LIBS). An increase in the sample temperature requires only simple modification to LIBS system, and does not require sample pretreatment. In addition, the formation and decay of laser-induced plasma (LIP) are a dynamic physical process. Time-resolved spectroscopy can enrich the dynamic information of LIBS and increase data dimension. The further analysis of the time-resolved LIBS data has the potential to understand the physical process. In this study, a beam of nanosecond laser was used to excite brass sample to produce plasma. The time-resolved spectroscopy of the LIP was measured at different sample temperatures. The results indicated that increasing sample temperature improved optical emission intensity in LIBS, and increased the plasma persistence. We also obtained plasma temperature and electron density at different sample temperatures. The time-resolved plasma temperature and electron density in the case with higher sample temperature were higher than those in the case with lower sample temperature. Moreover, the decay of electron density at higher sample temperature was faster than that at lower sample temperature.

Effect of temperature on GaSb nanocell lattice fabrication by void formation and development utilizing a focused ion beam

The effect of sample temperature on GaSb nanocell fabrication using a focused ion beam was investigated. Two-dimensional nanocell lattices with a cell interval of 100 nm were fabricated on GaSb at 135 K and 293 K. It was shown that the lattice develops slowly at 135 K with increasing ion dose, and that it does so quickly at 293 K, being disturbed by newly created secondary voids. These results were discussed using the migration parameters of point defects deduced from the recovery data of electron-irradiated GaSb by [Thommen, Phys. Rev. 161, 769 (1967)].

Temperature sensitivity of scattering-type near-field nanoscopic imaging in the visible range

Due to its superb imaging spatial resolution and spectroscopic viability, scattering-type scanning near-field optical microscopy (s-SNOM) has proven to be widely applicable for nanoscale surface imaging and characterization. However, limited works have investigated the sensitivity of the s-SNOM signal to sample temperature. This paper reports the sample temperature effect on the non-interferometric (self-homodyne) s-SNOM scheme at a visible wavelength (λ=638 nm). Our s-SNOM measurements for an arrayed vanadium/quartz sample demonstrate a monotonic decrease in signal intensity as sample temperature increases. As a result, s-SNOM imaging cannot distinguish quartz or vanadium when the sample is heated to ∼309 K: all signals are close to the root-mean-square noise of the detection scheme used for this study (i.e., 19μV-rms). While further studies are required to better understand the underlying physics of such temperature dependence, the obtained results suggest that s-SNOM measurements should be carefully conducted to meet a constant sample temperature condition, particularly when a visible-spectrum laser is to be used as the light source.