Effect Of Concentration Variation Research Articles

Spectroscopic Properties of Yb3+/Nd3+ Co-doped Ions in SiO2-Al2O3-Na2CO3-SrF2-CaF2 Oxyfluoride Glasses for Photonic Applications

The Yb3+ and Yb3+/Nd3+ co-doped SiO2-Al2O3-Na2CO3-SrF2-CaF2 oxyfluorosilicate glasses have been prepared by high temperature melt-quenching method. The prepared glasses are excited with 808 nm, and the near infrared emission bands are observed. The intensified emission band was centered at 1030 nm (2F5/2 -> 2F7/2) of Yb3+ ions. Stimulated emission cross-section was evaluated for the prominent 2F5/2 -> 2F7/2 transition of Yb3+ ion by using the Mc-Cumber theory. The energy transfer from Nd3+ to Yb3+ ions in co-doped silicate based oxyfluoride glasses are described under the 514 nm excitation wavelength. Full Text: PDF ReferencesN. Chiodini, A. Paleari, G. Brambilla, E. R. Taylor, "Erbium doped nanostructured tin?silicate glass?ceramic composites", Appl. Phys. Lett. 80, 4449 (2002). CrossRef D. Jaque, J. Capmany, F. Molero, Z. D. Luo, J. G. Sole, "Up-conversion luminescence in the Nd3+:YAB self frequency doubling laser crystal", Opt. mater. 10, 211 (1998). CrossRef H. Lin, G. Meredith, S. Jiang, X. Peng, T. Luo, N. Peyghambarian, E. Yue-Bun Pun, "Optical transitions and visible upconversion in Er3+ doped niobic tellurite glass", J. Appl. Phys. 93, 186 (2003) CrossRef Atul D. Sontakke, K. Annapurna, "Phonon assisted effective non-resonant energy transfer based 1 ?m luminescence from Nd3+?Yb3+ codoped zinc?boro?bismuthate glasses", J. Lumin. 138, 229 (2013). CrossRef F. Liegard, J.L. Doualan, R. Moncorge, M. Bettinelli, "Nd3+ ? Yb3+ energy transfer in a codoped metaphosphate glass as a model for Yb3+ laser operation around 980 nm", Appl. Phys. B 80, 985 (2005) CrossRef A. Miguel, B. Fan, R. Balda, X. Zhang, J. Fernandez, J.L. Adam, "Spectroscopy and energy transfer in Nd3 +/Yb3 + codoped chalcohalide glasses", J. Non-Cryst. Solids 377, 110 (2013). CrossRef G. Devarajulu, B. Deva Prasad Raju, "Effect of concentration variation on 2.0 ?m emission of Ho3+-doped SiO2?Al2O3?Na2CO3?SrF2?CaF2 oxyfluorosilicate glasses", App. Phy. A, 124 (2018). CrossRef Radoslaw Lisiecki, Elzbiecta Augustyn, Witold Ryba-Romanowski, Michal Zelechower, "Er-doped and Er, Yb co-doped oxyfluoride glasses and glass?ceramics, structural and optical properties", Opt. Mater. 33, 1630 (2011). CrossRef G. Chen, Q. Zhang, G. Yang, and Z. Jiang, "Mid-Infrared Emission Characteristic and Energy Transfer of Ho3+-Doped Tellurite Glass Sensitized by Tm3+", J. Fluoresc. 17, 301 (2007). CrossRef D. E. McCumber, "Theory of Phonon-Terminated Optical Masers", Phys. Rev. 134, 299 (1964). CrossRef D.L. Deloach, S.A. Payne, L.K. Smith, W.L. Kway, W. F. Krupke, "Laser and spectroscopic properties of Sr5(PO4)3F:Yb", J. Opt. Soc. Am. B 11, 269 (1994). CrossRef K. Venkata Krishnaiah, R. Rajeswari, K. UpendraKumar, S. Surendra Babu, I.R. Martin, C.K. Jayasankar, "Spectroscopy and radiation trapping of Yb3+ ions in lead phosphate glasses", J.Quant. Spect. Rad. Trans. 140, 37 (2014). CrossRef

Effect of concentration variation on 2.0 µm emission of Ho3+-doped SiO2–Al2O3–Na2CO3–SrF2–CaF2 oxyfluorosilicate glasses

The concentration variation of Ho3+ ion-doped SiO2–Al2O3–Na2CO3–SrF2–CaF2 glasses has been prepared by conventional melt quenching method. The thermal stability of 1 mol % of Ho3+-doped oxyfluorosilicate glass has been calculated using the differential thermal analysis (DTA) spectra. The phenomenological Judd–Ofelt intensity parameters Ωλ (λ = 2, 4 and 6) were calculated for all concentrations of Ho3+ ions. The luminescence spectra in visible region of Ho3+ ion-doped glasses were recorded under the excitation wavelength of 452 nm. The spectra consists of several intense emission bands (5F4, 5S2) → 5I8 (547 nm), 5F3 → 5I8 (647 nm), 5F5 → 5I7 (660 nm) and (5F4, 5S2) → 5I7 (750 nm) in the range 500–780 nm. The fluorescence emission at ∼2.0 µm (5I7 → 5I8) was observed under the excitation of 488 nm Ar-ion laser. The stimulated emission cross section for 5I7 → 5I8 transition (∼2.0 µm) varies from 8.46 to 9.52 × 10−21 cm2, as calculated by the Fuchtbauer–Ladenburg (FL) theory. However, Mc-Cumber theory was used to calculate emission cross section values about 4.24–5.75 × 10−21 cm2 for the 5I7 → 5I8 transition in all concentrations of Ho3+-doped oxyfluorosilicate glasses. Therefore, these results reveal that the 0.5 mol % of Ho3+-doped oxyfluorosilicate glasses, exhibiting higher emission cross section, has potentially been used for laser applications at ∼ 2.0 µm.

KAJIAN PENGARUH VARIASI KONSENTRASI ASAM SITRAT TERHADAP KEKUATAN GEL PRODUK GELATIN KULIT AYAM BROILER DIKAITKAN DENGAN POLA PROTEINNYA

Gelatin is a biopolymer that can be generated from partially hydrolysis of collagen tissue. Extraction of gelatin consists of pretreatment and thermal extraction steps. Pretreatment process used sodium hydroxide to remove non collagen protein in matrix sample, sulfuric acid to demineralize, and citric acid to hydrolyse. The aim of this research was to study the effect of variation in concentrations of citric acid used in hydrolysis process on the gel strength and protein profile of gelatin products extracted from broiler chicken skin. The variation of the concentration citric acid used was 0.7 % (GA); 1.5% (GB); and 3.0% b/v (GC) respectively. The gel strength was measured using CT3 Texture Analyzer and protein profile of gelatin product was analyzed by SDS-PAGE method. The result showed that variation in concentration of citric acid used in the pretreatment process affected the gel strength and protein profile of gelatin product. Increasing the concentration of citric acid used in pretreatment process decreased the gel strength and molecular weight of gelatin product. Gel strength of each gelatin product was 265.81 g bloom for GA ; 196.05 g bloom for GB (1.5%), and 35.32 g bloom for GC (3.0 %) respectively. The electropherogram of both GA (0.7%) and GB (1.5%) revealed similar pattern of protein bands but the thickness of each bands was different. On the other hands, GC (3.0%) did not show any protein bands on the eletropherogram. The best gelatin product obtained in this experiment was found by using 0.7 % b/v citric acid (GA) in the pretreatment process. The gelatin product (GA) had characteristics as follows: yield 15.73%; moisture 7.30%; ash 0.51%; protein content 97.95%; fat content 0.62%; gel strength 265. 81 g bloom and thicker protein bands than others.

Solidification of Sn–Pb alloys: Experiments on the influence of the initial concentration

A comparative study among solidification experiments for three selected alloys (Sn–3 wt.%Pb, Sn–6.5 wt.%Pb and Sn–10 wt.%Pb) was conducted on a benchmark experiment model under the same experimental conditions. The goal of this paper is to analyze the effect of variation in concentration on the solidification process with respect to different aspects: thermal, dynamic, structure, and morphology of segregation. Experimental results consist of instantaneous temperature maps provided by a lattice of 50 thermocouples welded on the large crucible side and post-mortem characterizations of the samples, such as X-ray imaging, solute local composition and metallography. Measurement of the instantaneous temperature field and numerical computation of liquid–solid interface evolution allows us to evaluate the effect of variation in concentration on thermosolutal convection behavior. Experimental results show that an increase in concentration greatly enhances the mechanism of the columnar-to-equiaxed transition (CET) and leads to refinement of the equiaxed structure. However, a significant effect of solutal element (lead) stratification is observed, which can slow down thermosolutal convection, in particular for large concentrations. Especially, without any stirring lead segregation which likely occurs during the melting phase may suppress natural convection. Furthermore, lead stratification is significantly reduced when electromagnetic stirring is opposed to natural convection before the solidification phase begins.

Controlled Release Ion Sensitive Floating Oral in situ Gel of a Prokinetic Drug using Gellan Gum.

Abstract: There are various approaches commonly used for gastric retention, one of which is raft forming system. Floating oral in situ gel is a type of raft forming system. The present work concerns with the formulation, evaluation and optimization of floating oral in situ gel of Itopride Hydrochloride for controlled release. Gellan gum has been used as a gel forming polymer and calcium carbonate as cross linking agent and Ca2+ ion source, and HPMC K100M as release retardant. The floating oral in situ gel undergoes gelation by ion sensitive mechanism. In this formulation 32 factorial designs was performed and the effect of variation in concentration of gellan gum and HPMC K100M on drug release at 1 h, 6 h, and viscosity was evaluated. The gel was evaluated for other parameters like floating lag time, floating duration, gel strength, density, pH, in vitro drug release, drug content, and in vitro gelling capacity. The results of 32 full factorial design revealed that the concentration of gellan gum and of HPMC K100M significantly affected the dependent variables i.e. drug release at 1 h, at 6 h, and viscosity. A controlled release profile was observed for these formulations. The drug release mechanism was found to follow Korsmeyer-Peppas model. In vivo studies revealed higher Tmax of gel compared to plain drug which is suggestive of slower absorption. However the AUC0-12 h was found to be nearly 90% higher than plain drug. Key words: in situ gel, CaCO3, Gellan gum, Foating drug delivery system, Ion Sensitive, Prokinetic.

Synthesis, characterization, and effect of concentration variation on metal oxide nanostructures

Zinc oxide (ZnO) has been successfully synthesized by an anodization method, and it has been fabricated through anodization method with different concentration of zinc nitrate. The element composition, surface inspection, structural, and morphological features of the products are depend on the concentration of zinc nitrate. At lower concentration (0.01M), SEM image shows ZnO nanowires with average width of about 30 and 50 nm. With increase in the concentration of zinc nitrate from 0.01 to 0.05 M, the nanowires change into the nanosheets with average width of about 0.5 and 1.5 μm. For samples (0.1 M) exhibits nanodots, morphology was composed of hundreds of nanosheets with thickness is about 90 nm on average. When the concentration increases to 0.2 M, the nanodots trench became bigger with diameter about 1.2–2.0 μm. When the concentration of zinc nitrate is 0.3 M, the average diameter of nanodots is about 2–2.5 μm. The trench of nanosheets becomes thinner and shorter, but the number of nanosheets increases with diameter 20–50 nm. The formation of nanowires, nanodots, and nanosheets nanostructures is also believed to result from actions on concentration of zinc nitrate as an aquas medium. The EDX result shows the atomic percentage (at.%) of the oxygen increased when the concentration of zinc nitrate increased. The pattern of EDX indicates that the ZnO nanostructures are composed of Zn, O, and Al. They represent Al composition in the sample because the anode using the aluminum rod during experiment.

A Modified Recipe and Variations for the Briggs–Rauscher Oscillating Reaction

A modified recipe for the Briggs–Rauscher oscillating reaction is suggested. The modified recipe, [H2SO4] = 0.10 M, [KIO3] = 0.020 M, [NaIO4] = 0.00062 M, [malonic acid] = 0.050 M, [MnSO4] = 0.0067 M, [H2O2] = 1.0 M with 0.01% starch, turns blue almost immediately, then oscillations start with two “slow” (∼25 s) cycles, then settle into regular approximately 12–15 s cycles. Oscillations end with a clear solution, avoiding cleanup of solid iodine resulting from the “standard” recipe, so that only neutralization of excess acid is needed before disposal. Effects of concentration variations are presented.

Phenylalanine as a hydroxyl radical-specific probe in pyrite slurries.

The abundant iron sulfide mineral pyrite has been shown to catalytically produce hydrogen peroxide (H2O2) and hydroxyl radical (.OH) in slurries of oxygenated water. Understanding the formation and fate of these reactive oxygen species is important to biological and ecological systems as exposure can lead to deleterious health effects, but also environmental engineering during the optimization of remediation approaches for possible treatment of contaminated waste streams. This study presents the use of the amino acid phenylalanine (Phe) to monitor the kinetics of pyrite-induced .OH formation through rates of hydroxylation forming three isomers of tyrosine (Tyr) - ortho-, meta-, and para-Tyr. Results indicate that about 50% of the Phe loss results in Tyr formation, and that these products further react with .OH at rates comparable to Phe. The overall loss of Phe appeared to be pseudo first-order in [Phe] as a function of time, but for the first time it is shown that initial rates were much less than first-order as a function of initial substrate concentration, [Phe]o. These results can be rationalized by considering that the effective concentration of .OH in solution is lower at a higher level of reactant and that an increasing fraction of .OH is consumed by Phe-degradation products as a function of time. A simplified first-order model was created to describe Phe loss in pyrite slurries which incorporates the [Phe]o, a first-order dependence on pyrite surface area, the assumption that all Phe degradation products compete equally for the limited supply of highly reactive .OH, and a flux that is related to the release of H2O2 from the pyrite surface (a result of the incomplete reduction of oxygen at the pyrite surface). An empirically derived rate constant, Kpyr, was introduced to describe a variable .OH-reactivity for different batches of pyrite. Both the simplified first-order kinetic model, and a more detailed numerical simulation, yielded results that compare well to the observed kinetic data describing the effects of variations in concentrations of both initial Phe and pyrite. This work supports the use of Phe as a useful probe to assess the formation of .OH in the presence of pyrite, and its possible utility for similar applications with other minerals.

Microencapsulation of Melaleuca alternifolia (Tea Tree) Oil by Using Simple Coacervation Method

Glutaraldehyde (GA) crosslinked gelatin (G) microcapsules containing tea tree oil (TTO) were prepared by the simple coacervation technique. The effects of variations in concentrations of the G, TTO and GA used during the microencapsulation process, on the oil load of the microcapsules, the oil content, the encapsulation efficiency and the release rate of oil were determined. The size distribution and the morphology of the microcapsules were characterized by optical and scanning electron microscopy. It was determined by FTIR studies that there was no evidence for any significant interaction between G and TTO

A dynamic performance model for redox-flow batteries involving soluble species

A transient modelling framework for a vanadium redox-flow battery (RFB) is developed and experiments covering a range of vanadium concentration and electrolyte flow rate are conducted. The two-dimensional model is based on a comprehensive description of mass, charge and momentum transport and conservation, and is combined with a global kinetic model for reactions involving vanadium species. The model is validated against the experimental data and is used to study the effects of variations in concentration, electrolyte flow rate and electrode porosity. Extensions to the model and future work are suggested.

Biomolecular detection with a thin membrane transducer

We present a thin membrane transducer (TMT) that can detect nucleic acid based biomolecular reactions including DNA hybridization and protein recognition by aptamers. Specific molecular interactions on an extremely thin and flexible membrane surface cause the deflection of the membrane due to surface stress change which can be measured by a compact capacitive circuit. A gold-coated thin PDMS membrane assembled with metal patterned glass substrate is used to realize the capacitive detection. It is demonstrated that perfect match and mismatch hybridizations can be sharply discriminated with a 16-mer DNA oligonucleotide immobilized on the gold-coated surface. While the mismatched sample caused little capacitance change, the perfectly matched sample caused a well-defined capacitance decrease vs. time due to an upward deformation of the membrane by a compressive surface stress. Additionally, the TMT demonstrated the single nucleotide polymorphism (SNP) capabilities which enabled a detection of mismatching base pairs in the middle of the sequence. It is intriguing that the increase of capacitance, therefore a downward deflection due to tensile stress, was observed with the internal double mismatch hybridization. We further present the detection of thrombin protein through ligand-receptor type recognition with 15-mer thrombin aptamer as a receptor. Key aspects of this detection such as the effect of concentration variation are investigated. This capacitive thin membrane transducer presents a completely new approach for detecting biomolecular reactions with high sensitivity and specificity without molecular labelling and optical measurement.

Structure of Zr-Cu and Zr-Ni Liquid Alloys Studied by High-Energy X-Ray Diffraction

In order to obtain an insight into the high glass-forming ability of bulk metallic glasses, we have analyzed liquid structures of the Zr-Cu and the Zr-Ni binary alloys with different compositions. High-energy (E = 113 keV) x-ray diffraction experiments were carried out for the liquid alloys levitated by a conical nozzle levitation (CNL) technique. While a peculiar shoulder on the second peak was observed in the structure factors of the Zr-Cu liquid alloys, those of the Zr70Ni30 and the Zr50Ni50 liquids exhibit an asymmetric shape of the second peak. In addition, it was found that the effect of concentration variation in the liquid Zr-Ni alloys was significantly different from that of the liquid Zr-Cu alloys. The liquid structure analyses using the reverse Monte Carlo (RMC) simulation have clarified that a degree of the short-range correlation between the constituents in the liquids affects substantially the glass-forming ability of the binary Zr alloys.

Natural gas electric generator powered by polymer exchange membrane fuel cell: Numerical model and experimental results

The reduction of pollutant emissions is an important advantage of fuel cells in small stationary power systems, particularly in combined heat and power generation (CHP). In fact, fuel cells are one of the future practical solutions for micro-CHP systems (5–10 kW) in the domestic environment. This paper reports numerical and experimental results of 5 kWe CHP H-Power units running on natural gas. The natural gas is reformed locally to produce hydrogen. The numerical model of the units allows the simulation of the operation of the reformer, the cooler-shift, the prox (preferential oxidation reactor) and of the PEMFC. The PEMFC polarization curve is determined by a subroutine taking into account mass and charge transfers and the condensation of liquid water in the electrodes membrane assembly (EMA). The molar flux of species through the anode and cathode porous backing layers is calculated analytically by means of the Stefan–Maxwell equations. The gas channels are assumed parallel to the EMA, and the effects of concentration variation are investigated. The relevance of the numerical results is first validated by comparison with experimental data; then, the performances of the system are analyzed in terms of electrical efficiency. Although the measured electrical performances are disappointing, the numerical simulations and analyses of experimental data suggest promising improvements. The model is employed to evaluate the best possible electrical efficiency and to establish the ideal operation domain of the installations.

Rotational parity and separation of water molecules into spin isomers

A theoretical explanation is proposed for the effect of variations in concentration of water molecule spin isomers in the gas phase during the interaction of molecules with a solid adsorbent surface. The explanation is based on antisymmetric (AS) correlation between proton spin moments and molecule rotation. A new AS correlation occurs during the interaction of the molecule with a dc electric field near the surface. Due to the new (external) AS correlation, ortho-and parawater molecules are formed; separation into spin modifications occurs over degenerate states of each rotational level of the molecule. Water molecule separation into spin modifications at the previous (internal) AS correlation occurs over rotational levels of molecules. The ratio of ortho-and parawater concentrations in the gas phase at the external AS correlation is compared with experimental data on chromatographic separation of water spin isomers. Quantitative agreement is observed between the calculated ratio and the ratio measured for water molecules at the final separation stage.

High Throughput Physical Organic Chemistry: Analytical Constructs for Monomer Reactivity Profiling

A polymer-supported analytical construct was used to quantify the reactivity of a range of monomers in the Ugi four-component condensation using positive electrospray ionization mass spectrometry (MS) as a quantitative analytical tool. The construct incorporated a bromo group to act as a peak splitter and a quaternary ammonium to act as a MS sensitizer and ionization leveler, thereby allowing direct quantitation of the cleaved adducts by MS. The relative reactivities of 10 carboxylic acids were quantified by the relative levels of product generated as determined by MS and 10 isonitriles, and 10 aldehydes were investigated in the same way. The effect of concentration variations on monomers reactivity and product profiles were rapidly determined using this approach, and the method opens up the way for studying, in a single pot, multiple reactions with a broad range of monomers under identical and self-consistent reaction conditions.

Assay and Analysis for Anti- and Pro-Oxidative Effects of Ascorbic Acid on DNA with the Bulk Acoustic Wave Impedance Technique

A bulk acoustic wave (BAW) impedance sensor has been applied for in situ monitoring of the whole process of DNA oxidative damage induced by the vitamin C (Vc)–Fe (III) system, based on its real-time responses to the density–viscosity change of the tested solution due to the damages occurring on the DNA molecules. The results showed that Vc exhibited two conflicting effects, i.e., pro-oxidation and anti-oxidation on the DNA at different Vc concentrations in the damage system, and the “threshold” concentration of Vc for these two effects was estimated to be about 100 μmol/L. The end-point frequency change of the sensor (Δfm) was found to be linearly related to the initial concentration of the soybean DNA (CDNA) in the range of 40–1000 μg/mL, and the exponential relationship between the frequency change (Δf0) vs damaging time suggested that the Fe (III)-mediated DNA damage by Vc could be described as a first-order kinetics reaction. The effects of variations in concentrations of Vc and Fe3+ on the DNA oxidative damage were discussed, and based on investigations for the enhancing influence of H2O2 and inhibiting influence of HO• scavengers on the DNA damage, the nature and physiological toxicity of the damage in biological system were also examined. In addition, UV-vis spectra and electrophoresis analysis were also used, and the experimental observations were in good agreement with the above results.

Photocatalytic hydrogen production by dye-sensitized Pt/SnO 2 AND Pt/SnO 2/RuO 2 in aqueous methyl viologen solution

Hydrogen photoproduction by a rarely studied, wide band gap semiconductor, SnO 2, in powder form loaded with Pt and RuO 2 and sensitized by Ru(bpy) 3 2+ and organic dyes or with low band gap semiconductor, CdS, was investigated. Acriflavin, Eosin Blue, Rhodamine B, Rose Bengal and Fluorescein were used as photosensitizers in the presence of methyl viologen and with or without a sacrificial agent, EDTA. The effects of variation in concentrations of Ru(bpy) 3 2+ and MV 2+ were studied. The maximum rate of hydrogen production was observed at [Ru(bpy) 3 2+] = 3.75 × 10 −5 mol dm −3 and [MV 2+] = 2.5 × 10 −5 mol dm −3. The efficiency of the sensitizers in hydrogen production was found to decrease in the order: Eosin Blue > Rose Bengal > Ru(bpy) 3 2+ > rhodamine B = acriflavin > fluorescein.

Rock-magnetic proxies of climate change in the loess-palaeosol sequences of the western Loess Plateau of China

SUMMARY Results of the first detailed study of the climate proxy record in the loess-palaeosol sequence at Xining-one of the few palaeoclimate sites in the currently arid western Loess Plateau of China-illustrate the importance of making many types of rockmagnetic measurements other than susceptibility. A multiparameter approach yielded confirmation that here, as elsewhere in the Loess Plateau, the susceptibility enhancement in palaeosols was caused primarily by ultrafine magnetite and maghaemite. Nevertheless, magnetic enhancement was caused not exclusively by changes in relative grain size, but also by variations in concentration and mineralogy of the magnetic fraction. The effects of concentration variations were removed through normalization of susceptibility and anhysteretic remanence with saturation magnetization and saturation remanence, respectively. The resulting signal was ascribed more confidently to variation in magnetic grain size, which in turn was interpreted as a better proxy of pedogenesis than simple susceptibility. Variations in magnetic mineralogy were also determined to constrain interpretations further. The data were then used to discuss climate history at Xining. Finally, results from Xining were compared with other western sites and contrasted with eastern sites. In summary: (1) data is presented from a new Loess Plateau site which also appears to yield a global climate signal; (2) a demonstration is made of a more rock-magnetically robust way to separate concentration, composition and grain-size controls on susceptibility and other magnetic parameters; and (3) models are provided for inter-regional comparisons of palaeoclimate proxy records.

A thin-film radiation monitoring label and dosimetry system

A thin plastic film was fabricated by casting on a polyester base a thin layer of poly(vinyl alcohol) (PVA) in aqueous solution with a mixture of dissoved sodium salt of 2,6-dichlorophenolindophenol (DPIP—Na) (a blue dye) and Sandolan Yellow N-3GL dye (SYN—3GL). This flexible, coated plastic film dosimeter undergoes a color change from green to yellow, with a sensitivity depending on DPIP—Na concentration. By changing the concentration of DPIP—Na in the film, one can predict the dose region at which the film will change its color from green to yellow. The response range of this dosimeter depends, in fact, on the DPIP—Na concentration and, in the case of 0.2 phr (by weight), it can be used up to absorbed doses of about 25 kGy, with a minimum useful dose of about 2 kGy. The effects of variation in concentration of DPIP—Na and thickness of film on response have been studied. The effects of absorbed dose, dose rate, temperature and relative humidity during irradiation and post-irradiation storage and exposure to daylight on dosimeter performance are also discussed. The usefulness of this dyed-film detector depends on its application. Using different concentrations of DPIP—Na, it can be applied as a green-to-yellow visual go-no-go monitor in the absorbed dose region 8–32 kGy. For dosimetry by spectrophotometry at 641 nm, the films show a linear response from 1 to 12 kGy.

Quantitative surface analysis of layered materials

AbstractThe effects of concentration variation with depth, C(X), on the quantitative reduction of electron spectroscopic data is discussed. It is shown that when the concentration varies with depth, quantitation of the data is affected by the escape depth of the electron transitions chosen for quantitation. Therefore, accurate quantitation is impossible without knowledge of C(X). A Laplace transform method to determine C(X) from angle‐resolved electron spectroscopic data is reviewed, along with potential problems caused by variation with angle of the escape depth of electrons in the solid, channeling, forward scattering, matrix corrections and surface roughness.