Use Of Blanks Research Articles

BLANK MATERIAL INFLUENCE ON STAMPING SPRINGBACK

This paper concerns the evaluation of blank material influence on springback of irregularly shaped stamping after drawing operation to keep the dimensions and tolerances of stamping after the drawing process which are given in part drawing. Simulation of the drawing process and consequent stamping springback were carried out by PAM-STAMP 2GTM software which uses the finite elements method, with the use of blanks from strip steels DX54D, HC220P, HX220BD and HX220YD. Two mesh strategies for drawing tool parts in the software PAM-STAMP 2GTM were compared. Stamping springback was evaluated with the use of a reference points system. Critical areas of deformations and stamping springback were evaluated. Simulation results were compared with measurements on real stampings. The most suitable strip steel in terms of achieving the minimum size of springback after stamping drawing was evaluated.

Analysis of non-hazardous canine training aids for triacetone triperoxide (TATP)

The purpose of this study was to analyze the headspace of non-hazardous canine training aids for triacetone triperoxide (TATP) that are currently available either for purchase or developed by a United States government entity. A total of eight training aids were analyzed using solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC–MS) to qualitatively identify the volatile compounds present in relative quantities over time until the depletion of TATP. At Time 0, ScentLogix™ had the highest relative abundance (211.2 ± 13.1 analyte/external standard (A/E)). While the SOKKS® aid contained no TATP, the aid with the lowest relative abundance at Time 0 was TOIDS (5.4 ± 0.7 A/E). As expected based on the abundance results, ScentLogix™ lasted the longest (at least 45 weeks) and TOIDS lasted the shortest period of time (2 days). However, ScentLogix™ also had the highest number of headspace components (acetone, diacetone alcohol, diacetone diperoxide, and TATP). Four of the tested training aids contained only TATP in the headspace: Odor Print, TOIDS, Getxent, and TATP POCR. Only four of the aids provided blanks (Getxent, TrueScent®, TA-SPOT®, and POCR), with the Getxent blank resulting in the lowest matrix odor. The manuscript concludes with a discussion of several considerations related to non-hazardous canine training aid selection, including the use of blanks, cost, storage, purity, and longevity.

Screening natural product extracts for potential enzyme inhibitors: protocols, and the standardisation of the usage of blanks in \u03b1-amylase, \u03b1-glucosidase and lipase assays

BackgroundEnzyme assays have widespread applications in drug discovery from plants to natural products. The appropriate use of blanks in enzyme assays is important for assay baseline-correction, and the correction of false signals associated with background matrix interferences. However, the blank-correction procedures reported in published literature are highly inconsistent. We investigated the influence of using different types of blanks on the final calculated activity/inhibition results for three enzymes of significance in diabetes and obesity; α-glucosidase, α-amylase, and lipase. This is the first study to examine how different blank-correcting methods affect enzyme assay results. Although assays targeting the above enzymes are common in the literature, there is a scarcity of detailed published protocols. Therefore, we have provided comprehensive, step-by-step protocols for α-glucosidase-, α-amylase- and lipase-inhibition assays that can be performed in 96-well format in a simple, fast, and resource-efficient manner with clear instructions for blank-correction and calculation of results.ResultsIn the three assays analysed here, using only a buffer blank underestimated the enzyme inhibitory potential of the test sample. In the absorbance-based α-glucosidase assay, enzyme inhibition was underestimated when a sample blank was omitted for the coloured plant extracts. Similarly, in the fluorescence-based α-amylase and lipase assays, enzyme inhibition was underestimated when a substrate blank was omitted. For all three assays, method six [Raw Data - (Substrate + Sample Blank)] enabled the correction of interferences due to the buffer, sample, and substrate without double-blanking, and eliminated the need to add substrate to each sample blank.ConclusionThe choice of blanks and blank-correction methods contribute to the variability of assay results and the likelihood of underestimating the enzyme inhibitory potential of a test sample. This highlights the importance of standardising the use of blanks and the reporting of blank-correction procedures in published studies in order to ensure the accuracy and reproducibility of results, and avoid overlooked opportunities in drug discovery research due to inadvertent underestimation of enzyme inhibitory potential of test samples resulting from unsuitable blank-correction. Based on our assessments, we recommend method six [RD − (Su + SaB)] as a suitable method for blank-correction of raw data in enzyme assays.

Parameter Measurement and Conductive Heating During Press Hardening by Hot Metal Gas Forming

Press hardening of steels for the production of car body components is very common. The reason for this is that the process allows the use of blanks with low wall thickness and the production of ultra-high strength components with complex geometries. The Hot Metal Gas Forming (HMGF) process for closed profiles combines the advantages of hydroforming, such as increased rigidity, functional integration or elimination of joining operations, with those of press hardening. In this paper results of continuous tests with actively cooled tools are presented in combination with temperature and displacement measurement. Furthermore, test results for HMGF with tool integrated conductive heating are demonstrated. Tests were done with tube material PHS1800 by SSAB, part temperatures over the Point of austenitisation and maximum internal pressure of 70 MPa. Thermocouples recorded the heat distribution in the tools. Other measured and recorded variables were the displacement of the component wall while forming under increasing internal pressure by a tactile displacement sensor and simultaneous temperature of its surface with a thermal sensor head. For the first time, information on pressure, the corresponding deformation stage and temperature profile could be documented during an entire forming step. A close to series production geometry DP4 was used to investigate the tool-integrated conductive heating of components.

Optical properties of large germanium monocrystals

Optical characteristics of germanium monocrystals with a diameter of 150 and 200 mm grown by the Czochralski and directional crystallization methods were studied. We measured spectral transmittance of the monocrystals in the wavelength range of 2.3–25.0 μm, directional transmission and light scattering in the 2.4–3.0 μm range, and noninhomogeneity of the refractive index of monocrystals by the interference technique at 3.39 μm. The measurements were performed on antimony-doped germanium monocrystals with a diameter of 200 mm and thickness of 15 mm (grown by the directional crystallization method) and 18 mm thick (grown by the Czochralski method). Measurements were also performed on a germanium monocrystal with a diameter of 150 mm and thickness of 15 mm grown by the Czochralski method without adding a ligand. The measurement results revealed different optical quality of monocrystals, expressed in the nature and amount of refractive index inhomogeneity, which imposes restrictions on the use of blanks.

Assessment of natural radioactivity and 137Cs in some coastal areas of the Saudi Arabian gulf

The levels of natural radioactivity have been investigated in some Saudi Arabian Gulf coastal areas. Sampling sites were chosen according to the presence of nearby non-nuclear industrial activities such as, the two main water desalination plants in Al Khobar and Al Jubail, and Maaden phosphate complex in Ras Al Khair, to ensure that effluents discharges into the Arabian Gulf didn't enhance radioactivity in seawater and shore sediments. Seawater samples were analyzed for radium isotopes (Ra-226 & Ra-228) and measured by gamma spectrometry using high purity germanium detector, after radiochemical separation of the isotopes by co-precipitation with MnO2. Shore sediment samples were analyzed for 226Ra, 228Ra (232Th), 4°K and 137Cs using gamma sepectrometry. A small variation was observed in the activity concentrations of the investigated radioisotopes, and the activity levels were comparable to those reported in literature. Quality assurance and methods validation were established through the efficiency calibration of the detectors, the estimation of uncertainties, the use of blanks, the analysis of standard reference materials and the intercomparison and proficiency tests. Radiological hazards were assessed, and the annual effective dose had an average value of 0.02mSv. On the basis of the current results, we may conclude that any radiological hazards to the public visiting these shores are not expected.

EXTRACTION OF RADIUM ISOTOPES FROM SOME COASTAL SEAWATER SAMPLES IN EGYPT METHOD VALIDATION

A radiochemical separation of Ra isotopeswas carried out to determine the activity levels of radium (226Ra and 228Ra)in seawater samples, as well as providing a base-line data on background radiation in the investigated locations. Seawatersamples were collected from selected sites along the coasts. The water samples were analyzed for radium isotopes (Ra-226 & Ra-228) using alpha and liquid scintillation detectors.Development steps were applied to the radioanalysis procedure by using calcium phosphate co-precipitation and the addition of isopropanol. Quality assurance and method validation of the developed procedure was carried out to assure the results. The obtained results were within the uncertainty level ± 5%. Quality control steps were applied through the efficiency calibration of the detectors, the estimation of uncertainties, the use of blanks and the comparison with other laboratories.For comparison, selected samples were measured by gamma spectrometry using high purity germanium detector, after radiochemical separation of the isotopes with ion-exchange chromatography using a strong cation exchange resin, and the activity concentrations of 228Ra were comparable with those analyzed by the LSC. The average activity concentrations of 226Ra and228Ra in the Mediterranean seawater samples were found to be 166.8 and 500.6 mBq/L respectively, while in the Red seawater samples were 13.0 and 176.7 mBq/L respectively. The maximum value of radium activity was found at RasElBarr estuary, where the River Nile fresh water mixes with the coastal seawater. On the basis of the current results, we may conclude that the radium activities in the investigated seawater samples are well comparable to the corresponding reported values in literature.

Appropriate Use of Blanks, Standards, and Controls in Chemical Measurements

It is critical to teach students the use of control samples, blanks, standards, dummy analyses, and system suitability checks to increase confidence in measurements. This article is intended as a concise primer on these topics that faculty can distribute to and discuss with their laboratory and research students, particularly undergraduate students. Our experience suggests that students sometimes do not appreciate the fundamental differences between these concepts. This article directly addresses those differences and clarifies the distinct functions served by each. It is also important to illustrate to students how these techniques can be incorporated into experimental protocols. Therefore, we end the manuscript with several case studies that illustrate how the incorporation of controls, blanks, standards, and dummy analyses can improve the reliability of chemical measurements and increase confidence in experimental data. Our intention is that students can then extrapolate what they learn from these examples and thereby improve their overall approach to science. We strongly encourage the routine incorporation of these methods in undergraduate laboratory experiments, both for their pedagogical value in developing good scientific habits and also to increase a student’s confidence in his or her ability to obtain correct results. While a discussion of overall experimental design issues such as sampling, reproducibility, factorial design, and randomization are outside the scope of this report, sources that discuss these topics extensively are referenced to provide a more complete introduction to experimental methods.

Effects of flange lubrication and blank geometry on square-shell deep drawability of hard pure aluminium sheets

The effects of lubrication, blank geometry and tool geometry on the deformation and fracture mechanisms of hard pure aluminium sheets in square-shell deep drawing were investigated. When hard aluminium square blanks were drawn using tools with a large corner radius, the reduction in friction in the corner flanges prevented localised fracture due to slip bands unique to hard aluminium sheets, and improved deep drawability. The use of blanks with an optimum geometry relieved severe deformation in the punch corners, thereby preventing localised fracture and improving deep drawability considerably. Several lines characterising the deep drawing of square shells were presented in the figures that show the relationships between corner-cut amount, drawing force and fracture force. In addition, a graphical method that uses the features of these lines for evaluating the limiting drawing ratio of optimum blanks was proposed.

Internal quality-control criteria for environmental monitoring of organic micro-contaminants in water

Laboratories have a strong, urgent need to assure the quality of their analytical results. Quality control (QC) is a key element in ensuring reliable results, because it requires both monitoring of the process and elimination of the causes of unsatisfactory performance. QC involves the use of blanks, certified reference materials (CRMs), duplicate samples, blind samples, and calibrating standards or spiked samples, among others. QC criteria are discussed for environmental monitoring of organic micro-contaminants in water. In addition, quality criteria in the identification and confirmation of target analytes are considered.

Natufian Settlement and Mobility: A Lithic Perspective from Saaïdé II, Lebanon

This study is concerned with settlement and mobility patterns from the perspective of the organization of the lithic technology. Radiating mobility patterns in the context of the Levantine Late Natufian are investigated by looking at the intensity of lithic reduction and the use of blanks for tool manufacture. By conjoining the results of the technological and morphological analysis of lithic tools with additional lines of evidence, such as site location, proximity to various resources, seasonal availability of resources, functional use of flint and non-flint artifacts, an integrated view has been reached on the intensity of human occupation at the Late Natufian site of Saaïdé II. With its large size, thick cultural deposits, varied tool kit and generalized subsistence, Saaïdé II was a residential camp for bands that subsisted on hunting and gathering. What enabled people to reside in this spot for more than one season was the overlap of seasonally available resources. The model of radiating mobility proposed for Saaïdé II illustrates that radiating mobility strategies were not abandoned with the onset of the climatic deterioration triggered by the Younger Dryas around 9,000 Be. Sites located in more marginal areas, beyond the boundaries of the Natufian "homeland", were able to sustain larger agglomerations of people and intensive human occupation.

Influence of fine grained structure and superplastic deformation on the strength of aluminium alloys

The influences of fine grained (FG) structure and superplastic deformation on the mechanical properties under quasistatic, impact and cycling loading conditions have been established for the aluminium alloys 1560 (Al-Mg-Mn), 1141 (Al-Cu-Mg-Ni-Fe) and 1960 (Al-Zn-Mg-Cu-Zr). FG materials compared with recrystallized coarse grained (CG) ones improve tensile strength and ductility and high-cycle fatigue endurance, but reduce static and impact toughnesses. The effect of grain refinement on crack resistance is directly manifested in the difficulty of crack initiation and in facilitating its growth. Blanks with FG structure, after superplastic processing, are recommended instead of CG recrystallized ones for the production of principal parts whose service life is limited by first crack appearance. In the presence of cracks, higher strength can be obtained by the use of blanks made of CG commercial semifinished products and those manufactured by traditional methods of hot die forging.

Utilisation du tribulum au début du IIIe millénaire : des lames « cananéennes » lustrées à Kutan (Ninive V) dans la région de Mossoul, Iraq

The technological and functional characteristics of fragmented « Canaanean-type » blades with gloss have been studied using two methods. Microwear traces, identified on 18 fragments (of 1 45 found) in comparison with analysis of flint from ethnographic threshing sledges (tribulum), have shown that the tribulum was used in the Ninivite V village of Kutan (Iraq) in the beginning of the third millennium B.C. This discovery widens the range of functional interpretations of glossed tools, and analysis of this original blade débitage technique more precisely describes the term « Canaanean » as well as the techno-economic system to which it was related. These blades were produced using a metal punch or by pressure, using a lever. At Kutan, there was a local, « low technical investment » economy, co-existing with a standardized production of these « Canaanean » blade fragments, which does not appear to be local. The latter production is characterised by a high level of mastery of knapping techniques, and also implies, by the dimensions of its products (blades can be up to 25 cm), that the raw material is of high quality, abundant and large. This imported blade economy appears to be related to use of blanks for agricultural implements (sickles, followed by re-use in threshing sledges). Key-words : Kutan, tribulum, Canaanean blades, microwear analysis.

AN IMPROVED PROCEDURE FOR THE DETERMINATION OF CHROMIC OXIDE IN FEED AND FECES

A spectrophotometric procedure was developed using ashing at 450 °C followed by acid digestion in beakers and reading the diluted digests at 440 nm. Errors were minimized by use of blanks and maintenance of a constant acid concentration in the diluted digests.

Redundancy Rules in Phonology

This work contains a discussion of redundancy rules and the role they play in the phonological component of a generative grammar. Phonological redundancy rules were first given a clear theoretical foundation in the MORPHEME STRUCTURE RULES used by Halle (1959) to predict redundant phonological information in morphemes. We will be concerned in what follows with reformulating and extending this original theory of morpheme structure rules. We will give particular attention to the formal nature of morpheme structure rules and to the use of blanks in representing redundancies, and will give a solution to a long-standing problem in this area. In spite of this improvement in morpheme structure rule theory, we will find other motivations for introducing a new formal device, MORPHEME STRUCTURE CONDITIONS, to replace morpheme structure rules. We will attempt to show that, both in the types of statements which can be made about the structure of morphemes and in the formal nature of these statements, morpheme structure conditions are to be preferred over morpheme structure rules.

On the directionality of the one way rolling aluminium sheet and the detection of directionality by meaus of the Knoop indentor

Experiments for studying on earing grown by deep drawing were made by use of blanks from one-way-rolled 2S sheets which were produced through following processes. Three 2S ccp slabs were pre-heated for two, five and seven hours at 500°C respectively. These slabs were rolled under the temperature of 500°C, 510°C and 520°C and then cold-rolled with the reduction rates of 73.4%, 87.1% and 92.9% respectively. Annealing temperature was changed in the range of 265°C-400°C.From these experiments, it was found out that, compared with the ones from cross-way-rolled sheets, blanks from one-way-rolled sheets make much more remarkable 45°-earings, when deep-drawn. As the reduction rate increases, the 45°-earings become more remarkable. when the reduction rate is low and annealing temperature is beyond the recrystallization temperature, the 45°-earings are passed into 0°-or 90°-earings.But, when the reduction rate is high, the 45°-earing does not disappear. The effect of the difference of pre-heating time was so slight that it could not be expressed as a general inclination. The effect of rolling temperature was also not so remarkable. On the other hand, the directionality of these sheets were detected through the Knoop ratio. It wao found out that the ratiom of (maximum Knoop ratio)/(mean knoop ratio) shows the similar inclination to the growth of earings, and thus the directionality of sheet can be found by Knoop ratio. From this experiment, it was proved that Knoop ratio can be used for detecting the directionality of sheet, as previously proposed by the auther.