Effects Of Sample Position Research Articles

Effect of sample position on formation of spatial-self phase modulation ring patterns in poly(azaneylylidene-acylene)

Poly(azaneylylidene-acylene) "DAZA" polymer has been synthesized and characterized using different spectroscopic techniques. Self-diffraction ring patterns at far field were observed, when the DAZA polymer was irradiated with a CW laser beam. The influence of sample position, geometrical pumping and laser power has been investigated on the formation of the far field self-diffraction ring patterns of the Gaussian laser beam passing through the DAZA polymer as nonlinear medium. Then, the Fresnel-Kirchhoff diffraction formula was applied to perform simulation of the self-diffraction ring patterns with different laser power at two sample positions before and after the focal point (z = 0) with respect to the geometrical pumping. Our results have shown the effect of type of geometrically pumping on the sample cell (horizontally /vertically) with respect to the distortion of the SSPM patterns. It has been found that, good consistent agreements between experimental and theoretical patterns.

Effect of sampling position in fresh, dry-aged and wet-aged beef from M. Longissimus dorsi of Simmental cattle analyzed by 1H NMR spectroscopy

The aging of beef affects the metabolome and, thus, its quality, such as taste or tenderness. In addition to the aging method, intrinsic factors, such as breed, feed and muscle type, also have an effect on beef’s metabolome. It is not known yet whether the position of the sampling in large muscles also has an influence on beef’s metabolome and its aging outcome. The effect of the sampling position in M. longissimus dorsi as a large muscle was investigated in dry-aged and wet-aged beef over an aging period of 28 days. In this study, we analyzed 360 samples out of the entire length of M. longissimus dorsi of 18 ‘Simmental’ young bulls by 1H NMR spectroscopy. The position in the muscle affected the polar fraction of metabolome of non-aged and aged beef significantly. However, sampling position did not overlay significant differences in the metabolome of dry-aged and wet-aged beef. The aging time of beef also had a significant effect on the metabolome. Marker metabolites, such as leucine, isoleucine, inosine 5′-monophosphate and hypoxanthine, were found to be indicative of the aging time applied. In addition, marker metabolites (lactic acid, anserine, O-acetyl-L-carnitine) were identified for the aging type applied.

Preferred Pore Orientation as a Complement to Anisotropy of Magnetic Susceptibility: A Case Study of Lava Flows From Batur Volcano, Bali, Indonesia

Anisotropy of magnetic susceptibility (AMS) analyses have been used widely in many applications that include studying lava flows. In this paper, we introduce an auxiliary parameter, i.e., preferred pore orientation, on the use of AMS for lava flow studies on the basaltic lava samples from Batur Volcano in Bali Indonesia. We also examine the effect of sample position in lava flow outcrop to the relationship between preferred pore orientation and AMS. The samples are subjected to petrographic analyses as well as to magnetic measurements and micro-computed tomography (μCT) imaging. Preferred pore orientations were obtained by quantified the long-axis of the vesicles from the images. The correlation was evaluated by measuring the angle between the maximum susceptibility axes and the preferred pore orientations. All samples show that the maximum susceptibility axes are parallel with the flow direction. Three out of six samples of two lava flows from the same eruption show a positive correlation between AMS and preferred pore orientation, where both parameters point to the northeast direction. A difference of sample position in the outcrop of lava flow was observed as a possible factor that influenced the results for the preferred pore orientations. Samples which were taken from the summit of the lava flow have pore orientation parallel to the lava flow direction. While samples which were taken from the foot slope of the lava flow have pore orientation perpendicular to the lava flow direction. This study provides further evidence that pore orientation might be positively correlated with the AMS.

Polycyclic aromatic hydrocarbon contamination of Polish smoked fish: Assessment of dietary exposure

The aim of the study was to determine if the smoked fish being produced in Poland complies with the new, stricter limits set for BaP and PAH4. The effect of sample position in the smoking chamber was also studied. The margin of exposure (MoE) approach was used for assessing the risk of dietary exposure to PAHs from smoked fish products. The study material comprised of sprat, herring, mackerel, and salmon from a fish processing plant equipped with smoking chambers with external smoke generators. None of the smoked fish products studied exceeded the new, stricter limits set for BaP and PAH4. The MoE indicators far exceed the limit of 10,000 (values lower than this indicate a potential risk to consumer health). The sensory analysis identified significant differences among the products studied that indicate the high quality of cold‐smoked salmon fillets and the statistically significant lower quality of a smoked salmon abdominal parts. PRACTICAL APPLICATIONS: In 2011 and 2015, the European Commission amended Regulation No. 1881/2006, setting new maximum levels for polycyclic aromatic hydrocarbons in food products in order to protect consumer safety. The currently applicable limits are: for benzo(a)pyrene—2.0 μg/kg and for the sum of benzo(a)pyrene, benz(a)anthracene, benzo(b)fluoranthene, and chrysene—12.0 μg/kg in muscle meat of smoked fish and smoked fishery products with the exception of smoked, canned smoked sprat, smoked, and canned smoked Baltic herring ≤ 14 cm, where the limits are, respectively, 5.0 μg/kg and 30.0 μg/kg. The presented study was to determine if the sprat, herring, mackerel, and salmon from a fish processing plant equipped with smoking chambers with external smoke generators comply with the new, stricter limits set for BaP and PAH4 by Regulation No. 835/2011 and No. 2015/1125. The results showed that none of 54 smoked fish products that had been examined exceeded the new, stricter limits set for BaP and PAH4 and also that changes in PAH4 content depending on the position of the product in the smoking chamber were statistically insignificant, what is important information for processing plants. The sensory analysis indicated the high quality of cold‐smoked salmon fillets and the statistically significant lower quality of smoked salmon abdominal parts.

Measuring the compressive modulus of elasticity of pith-filled plant stems

BackgroundThe compressional modulus of elasticity is an important mechanical property for understanding stalk lodging, but this property is rarely available for thin-walled plant stems such as maize and sorghum because excised tissue samples from these plants are highly susceptible to buckling. The purpose of this study was to develop a testing protocol that provides accurate and reliable measurements of the compressive modulus of elasticity of the rind of pith-filled plant stems. The general approach was to relying upon standard methods and practices as much as possible, while developing new techniques as necessary.ResultsTwo methods were developed for measuring the compressional modulus of elasticity of pith-filled node–node specimens. Both methods had an average repeatability of ± 4%. The use of natural plant morphology and architecture was used to avoid buckling failure. Both methods relied up on spherical compression platens to accommodate inaccuracies in sample preparation. The effect of sample position within the test fixture was quantified to ensure that sample placement did not introduce systematic errors.ConclusionsReliable measurements of the compressive modulus of elasticity of pith-filled plant stems can be performed using the testing protocols presented in this study. Recommendations for future studies were also provided.

Microstructure and mechanical properties of sheep horn.

The sheep horn presents outstanding mechanical properties of impact resistance and energy absorption, which suits the need of the vehicle bumper design, but the mechanism behind this phenomenon is less investigated. The microstructure and mechanical properties of the sheep horn of Small Tailed Han Sheep (Ovis aries) living in northeast China were investigated in this article. The effect of sampling position and orientation of the sheep horn sheath on mechanical properties were researched by tensile and compression tests. Meanwhile, the surface morphology and microstructure of the sheep horn were observed using scanning electron microscopy (SEM). The formation mechanism of the mechanical properties of the sheep horn was investigated by biological coupling analysis. The analytical results indicated that the outstanding mechanical properties of the sheep horn are determined by configuration, structure, surface morphology and material coupling elements. These biological coupling elements make the sheep horn possess super characteristics of crashworthiness and energy absorption through the internal coupling mechanism. We suppose that these findings would make a difference in vehicle bumper design. Microsc. Res. Tech. 79:664-674, 2016. © 2016 Wiley Periodicals, Inc.

Three-dimensional simulation of microwave heating coal sample with varying parameters

This paper aims to predict the heating behaviors of coal sample by COMSOL Multiphysics software based on the finite element method. The effects of microwave frequency, microwave power and sample position on temperature profiles and electric field distributions are examined. The effect of microwave frequency on temperature is obvious. The maximum and minimum temperatures of the coal sample change with frequency in different laws respectively. There is just one optimal heating frequency to achieve the maximum or minimum value of temperature. The effect of microwave power on temperature is found evidently, too. The lower power microwave-treatment requires more energy than microwave-treatment with a higher power when the heating temperature is greater than 200 °C. And there is an optimal temperature between 100 °C and 200 °C, which energy input is equal to each other under different power inputs. The effect of sample position on the temperature is also remarkable. The maximum and minimum temperatures of the coal sample change with position in different laws respectively. The results can serve as references for the study on heating coal sample by microwave heating system.

Effect of sample position on collinear femtosecond double-pulse laser-induced breakdown spectroscopy of silicon in air

A femtosecond double-pulse laser was used to induce the plasma of silicon in air. The laser wavelength was 800 nm. The interpulse delay of the femtosecond double-pulse was from −20 ps to 100 ps. During the experiment, the spectral line was fixed at the wavelength of 288.157 nm. The emission intensity was observed to lead to a significant increase by choosing the proper sample position. The range of the sample position is from 5.17 mm to 5.27 mm. And, the best sample position for the higher laser fluence was different from the position for the lower laser fluence. At the higher laser fluence, the optimized emission intensity can be obtained at either side of the best focal position for all interpulse delays of the double-pulse. The phenomena can be explained by the nonlinear propagation of the femtosecond laser pulse in air. At the lower laser fluence, the best sample position will change from one side to both sides with the increase of the interpulse delay of the double-pulse. The results showed that the effect of the sample position can be especially advantageous in the context of femtosecond double-pulse laser-induced breakdown spectroscopy. The study will lead a further improvement in the applications of the femtosecond double-pulse laser.

Argon plasma treatment-induced grafting of acrylic acid onto expanded poly(tetrafluoroethylene) membranes

Expanded poly(tetrafluoroethylene) (ePTFE) is used in facial reconstruction surgery. For some specific applications ePTFE is required to interface with the underlying bone. However, ePTFE is classified as bioinert thus limiting integration at the bone-tissue interface. The incorporation of functional groups onto the ePTFE surface was carried out in the current study using argon plasma treatment-induced grafting of acrylic acid (AA) to improve integration. High surface coverage (grafting extent from XPS of up to 90%) was achieved and resulted in high hydrophilicity and high water uptake (up to 470% of the grafted PAA mass). The contribution of species present in the plasma to the incorporation of functional groups onto the ePTFE surface was evaluated with charged species observed to play an equally important role to neutral species in this study. The effects of sample position in the plasma chamber as well as the effect of grafting parameters (plasma power, monomer concentration, and reaction time) on the grafting outcome were evaluated. The mechanical properties of the AA grafted membranes under tensile, compression and nanoindentation were evaluated.

The Effects of Sample Position and Gas Flow Pattern on the Sintering of a 7xxx Aluminum Alloy

The effects of sample position and gas flow pattern on the sintering of a 7xxx aluminum alloy Al-7Zn-2.5Mg-1Cu in flowing nitrogen have been investigated both experimentally and numerically. The near-surface pore distribution and sintered density of the samples show a strong dependency on the sample separation distance over the range from 2 mm to 40 mm. The open porosity in each sample increases with increasing separation distance while the closed porosity remains essentially unchanged. A two-dimensional computational fluid dynamics (CFD) model has been developed to analyze the gas flow behavior near the sample surfaces during isothermal sintering. The streamlines, velocity profile, and volume flow rate in the cavity between each two samples are presented as a function of the sample separation distance at a fixed nitrogen flow rate of 6 L/min. The CFD modeling results provide essential details for understanding the near-surface pore distribution and density of the sintered samples. It is proposed that the different gas flow patterns near the sample surfaces result in variations of the oxygen content from the incoming nitrogen flow in the local sintering atmosphere, which affects the self-gettering process of the aluminum compacts during sintering. This leads to the development of different near-surface pore distributions and sintered densities.

Spatial distribution of roots of pearl millet on sandy soils of Niger

Root sampling in crop stands of low planting density requires reliable information on horizontal distribution of roots. This applies particularly to pearl millet in the Sahel, which is sown at a rate of less than two pockets of seed per m2. The objective of this study was to investigate the spatial variability of root length density (RLD) among sampling positions in an improved management system with ridging and under traditional sowing. RLD between ridges (bR) was lower compared to sampling positions within ridges (wR) at soil depth layers from 0 to 80 cm soil depth. We found a highly significant, positive correlation between the sum of the root length (RL) of four sampling dates (tillering, booting, flowering, and maturity) with shoot dry mass (SDM) at maturity. The square of the correlation coefficient was highest when calculation of RL was based on RLD at all four sampling positions. While SDM exhibited significant differences among three pearl millet varieties, sole root sampling wR at a lateral distance of 60 cm relative to the pocket would not allow for the detection of varietal differences in RL, while all other sampling positions did. The correlation between RL and SDM was considerably improved if information of RLD bR was included. Under traditional sowing, RLD directly under the plant was lower compared to sampling positions at lateral distance 25 and 50 cm from the centre of the pocket, but this effect of sampling position was not significant. RLD estimates within deeper soil layers were not systematically affected by direction and lateral distance. To obtain accurate information about depth of rooting and RL under traditional sowing, samples should be taken from lateral distances between 20 and 40 cm from the pocket centre.

Studies on fracture behavior of tough PA6/PP blends

Fracture toughness of injection-molded PA6/PP blends compatibilized with SEBS-g-MA was studied using deeply double-edge notched tension (DDENT) specimens according to the essential work of fracture procedure. The fracture mechanical studies also included tensile impact tests on the DDENT specimens and characterization of the fracture surfaces by electron microscopy. The results were compared with those of traditional tensile tests and Izod impact tests on single-edge notched samples, and the sensibility of the methods was evaluated. Effects of sample position, ligament length, testing direction, and test speed were studied as well. It was found that the essential work of fracture concept, earlier applied to thin sheets, can also be applied to injection-molded tough blends. High deformation of the skin may, however, interfere with the measurements and cause a “tail” in the load-deformation curves. The plastic work of fracture (wp) was found to correlate with the impact strength, and thus, it described the toughness. The highest values for work of fracture were recorded for the compatibilized blend with a PA6/PP ratio of 80/20. The essential work of fracture (we) in turn increased with increasing PA6 content and behaved like tensile strength. The test speed was found to affect the fracture behavior substantially: differences between the materials were more pronounced in high-speed tensile impact tests, which revealed signs of cavitation in addition to large-scale plastic deformation for the tough PA6-rich blend compositions. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2209–2220, 1997

The Effect of Sampling position from cast blocks on Fatigue Properties for Spheroidal Graphite Cast Iron.

Rotating bending fatigue tests at room temperature were carried out on a ferritic spheroidal cast iron (FDI) and a ferritic/pearlitic spheroidal cast iron (FPDI). Two series of fatigue specimens were machined out from a and an positions of the cast Y-blocks, which were called lower specimen and upper specimen, respectively. Using these specimens, the fatigue strength and fatigue life distributions were investigated. The major results obtained were as follows. (1) The fatigue strength of specimens was higher than that of ones for FDI and FPDI. (2) In both materials, the average graphite size of the specimens was smaller than that of the one. (3) The average graphite size had a main effect on fatigue strength and fatigue life distributions.

The effect of sample position on the determination of triaxial stress by X-ray diffraction

The determination of the full three-dimensional stress tensor in a specimen by X-ray diffraction requires that the strain be measured with the sample tilted in both a positive and a negative sense for different rotations of the sample in its own plane. The error introduced in the measured strain as a function of the position of the specimen relative to the X-ray diffractometer axis is investigated and it is shown that the negative tilt values are more sensitive to sample position than the positive tilt values. The determination of the shear stress components uses the difference between the measured strain at equivalent positive and negative tilts and hence it is shown that displacement of the sample could lead to incorrect deductions concerning the presence and magnitude of the shear stress components.