Peak Height Method Research Articles

Elaboration of an innovative plant biomaterial for its valorization in the treatment of wastewater

The global scientific community is deeply concerned about the deterioration of water quality resulting from the release of industrial effluents. This issue is of utmost importance as it serves to safeguard the environment and combat water pollution. The objective of this work is to elaborate a biomaterial of vegetable origin, based on the twigs of Aleppo pine, and to use it as an abundant and less expensive material for the treatment of wastewater. For this reason, the twigs were treated physically to get the powder called biomaterial FPA (Aleppo pine fiber), which was characterized by physicochemical, and spectroscopic analyses namely scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The crystallinity index of FPA was evaluated by the peak height method. The findings indicate that the FPA powder has an acidic nature, exhibiting a porous structure that promotes the adsorption and binding of molecules. Additionally, it has a zero charge point of 5.8 and a specific surface area of 384 m2.g−1. It is primarily composed of hydroxyl, carboxyl, and amine functional groups, along with mineral compounds and organic compounds, including cellulose and other mineral elements such as Ca, Mg, Fe, Na, P, Al, K, Ni, and Mo. Combining these characteristics, FPA biomaterial has considerable potential for use as an effective adsorbent biomaterial for various wastewater pollutants. Its abundance and relatively low cost make it an attractive solution to the growing challenges of water pollution worldwide.Graphical

Recommended Practices for More Accessible Quantification of Low‐Concentration Aqueous Phase Products in Photo/Electrocatalytic CO2/N2 Fixation

AbstractThe sustainable development of novel photo/electrocatalytic CO2/N2 fixation for chemical synthesis is predicated on reliable, accurate, and rapid detection methods. The directness, specificity, and simultaneity in detecting multiple molecules of the 1H nuclear magnetic resonance (1H‐NMR) technique have aroused increasing interest in photo/electrocatalysis. Thus far, two data processing means have been developed for the precise 1H‐NMR data processing: peak integral and peak height methods. However, few detailed studies offer a clear steer for choosing data processing methods for the concerned products in photo/electrocatalysis, especially the guidelines under the conditions of baseline distortions induced by water suppression. Herein, the feasible practices are restudied to quantify classical products in photo/electrocatalytic CO2/N2 fixation. On the basis of experimental results, 1H‐NMR data processing methods (peak integral and peak height methods) are found to convey different applicability for the different low‐concentration products, while introducing water suppression in the 1H‐NMR tests. The essential reason can be attributed to the baseline distortions caused by the water suppression, which arouses differentiated deviation of peaks with different peak widths. With this in mind, an accessible quantification criterion is provided to avoid superfluous input of time or cost in precise 1H‐NMR detection of low‐concentration products.

Validation of central peak height method for final adult height predictions on long leg radiographs.

Accurate skeletal age and final adult height prediction methods in paediatric orthopaedics are crucial for determining optimal timing of growth-guiding interventions and minimizing complications in treatments of various conditions. This study aimed to evaluate the accuracy of final adult height predictions using the central peak height (CPH) method with long leg X-rays and four different multiplier tables. This study included 31 patients who underwent temporary hemiepiphysiodesis for varus or valgus deformity of the leg between 2014 and 2020. The skeletal age at surgical intervention was evaluated using the CPH method with long leg radiographs. The true final adult height (FHTRUE) was determined when the growth plates were closed. The final height prediction accuracy of four different multiplier tables (1. Bayley and Pinneau; 2. Paley et al; 3. Sanders - Greulich and Pyle (SGP); and 4. Sanders - peak height velocity (PHV)) was then compared using either skeletal age or chronological age. All final adult height predictions overestimated the FHTRUE, with the SGP multiplier table having the lowest overestimation and lowest absolute deviation when using both chronological age and skeletal age. There were no significant differences in final height prediction accuracy between using skeletal age and chronological age with PHV (p = 0.652) or SGP multiplier tables (p = 0.969). Adult height predictions with chronological age and SGP (r = 0.769; p ≤ 0.001), as well as chronological age and PHV (r = 0.822; p ≤ 0.001), showed higher correlations with FHTRUE than predictions with skeletal age and SGP (r = 0.657; p ≤ 0.001) or skeletal age and PHV (r = 0.707; p ≤ 0.001). There was no significant improvement in adult height prediction accuracy when using the CPH method compared to chronological age alone. The study concludes that there is no advantage in routinely using the CPH method for skeletal age determination over the simple use of chronological age. The findings highlight the need for more accurate methods to predict final adult height in contemporary patient populations.

Optimization of microfibrillated cellulose isolation from cocoa pod husk via mild oxalic acid hydrolysis: A response surface methodology approach

Theobroma cacao L. species, cultivated worldwide for its valuable beans, generates up to 72% weight of the fruit as waste. The lack of reutilization technologies in the cocoa agroindustry has hindered the exploitation of valuable bio-components applicable to the generation of high value added bioproducts. One such bioproduct is microfibrillated cellulose (MFC), a biopolymer that stands out for its desirable mechanical properties and biocompatibility in biomedical, packing, 3D printing, and construction applications. In this study, we isolated microfibrillated cellulose (MFC) from cocoa pod husk (CPH) via oxalic acid hydrolysis combined with a steam explosion. MFC isolation started with the Solid/Liquid extraction via Soxhlet, followed by mild citric acid hydrolysis, diluted alkaline hydrolysis, and bleaching pre-treatments. A Response Surface Methodology (RSM) was used to optimize the hydrolysis reaction at levels between 110 and 125 °C, 30–90 min at 5–10% (w/v) oxalic acid concentration. The cellulose-rich fraction was characterized by Fourier-Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) analyses. Characterization analyses revealed a cellulose-rich polymer with fibers ranging from 6 to 10 μm, a maximum thermal degradation temperature of 350 °C, and a crystallinity index of 63.4% (peak height method) and 29.0% (amorphous subtraction method). The optimized hydrolysis conditions were 125 °C, 30 min, at 5% w/v oxalic acid: with a 75.7% yield. These results compare with MFC obtained through highly concentrated inorganic acid hydrolysis from different biomass sources. Thus, we show a reliable and greener alternative chemical treatment for the obtention of MFC.

Characterization of Natural Fiber Extracted from Corn (Zea mays L.) Stalk Waste for Sustainable Development

Corn stalk fibers were extracted from corn stalk using sodium hydroxide for textile application. The extraction conditions were optimized on the basis of the quality and quantity of extracted fibers. The optimum conditions were obtained by treating corn stalk with 5 g/L concentration of sodium hydroxide for 60 min at boiling temperature using a 1:50 material-to-liquor ratio. Extracted fibers were bleached and tested for different physical and chemical properties. Besides these properties, the characterization of extracted fibers was carried out by a scanning electron microscope (SEM), X-ray diffraction analysis (XRD) and Fourier–transform infrared (FTIR) analysis. SEM was used to study the morphological changes in the raw and bleached fibers. The crystallinity changes of the raw and bleached samples were measured with an X-ray diffractometer by peak height method. FTIR was used to examine the compositional changes in the bleaching process. It was found that raw fibers contained the cellular residues such as lignin and hemicelluloses, which cement the fibers together. The chemical treatments such as alkali and bleaching partially removed hemicelluloses, lignin, and amorphous fractions of cellulose. This led to the gradually increasing crystallinity of the treated fiber. Peak height values were obtained by measuring the transmittance of the spectra through FTIR analysis. Different physical and chemical properties of the extracted corn stalk fibers indicated that it can be used for making biodegradable composite materials.

Mechanical Amorphization of Chitosan with Different Molecular Weights.

Mechanical amorphization of three chitosan samples with high, medium, and low molecular weight was studied. It is shown that there are no significant differences between the course of amorphization process in a planetary ball mill of chitosan with different molecular weights, and the maximum degree of amorphization was achieved in 600 s of high intensity mechanical action. Specific energy consumption was 28 kJ/g, being comparable to power consumption for amorphization of cellulose determined previously (29 kJ/g) and 5–7-fold higher than that for amorphization of starch (4–6 kJ/g). Different techniques for determining the crystallinity index (CrI) of chitosan (analysis of the X-ray diffraction (XRD) data, the peak height method, the amorphous standard method, peak deconvolution, and full-profile Rietveld analysis) were compared. The peak height method is characterized by a broader working range but provides deviated CrI values. The peak deconvolution method (with the amorphous Voigt function) makes it possible to calculate the crystallinity index of chitosan with greater accuracy, but the analysis becomes more difficult with samples subjected to mechanical processing. In order to refine the structure and calculation of CrI by the Rietveld method, an attempt to optimize the structure file by the density functional theory (DFT) method was performed. The averaged profile of amorphous chitosan approximated by an eighth-order Fourier model improved the correctness of the description of the amorphous contribution for XRD data processing. The proposed equation may be used as a universal standard model of amorphous chitosan to determine the crystallinity index both for the amorphous standard method and for peak deconvolution of XRD patterns for arbitrary chitosan samples.

EFFECTS OF BUTYLAMINE TREATMENT ON CELLULOSE FIBERS DURING RECYCLING OF OLD CORRUGATED CONTAINERS (OCC)

This study aimed to determine the effects of butylamine treatment on cellulose fibers during the recycling processes. Three recycling stages have been carried out and two different butylamine (Ba) treatments (5.0% and 7.5%) were applied to old corrugated containers (OCC) papers during recycling. After each recycling process, papers were produced and the mechanical and optical properties of these papers were measured. SEM images and FTIR spectra were taken and the crystallinity index of the cellulose fiber was calculated by the XRD peak height method. Some improvement (11.0-15.2%) in paper brightness with the Ba treatment was realized in the third recycling stage, while yellowness values typically decreased by 1-2 points. Chemical treatments resulted in definite differences in water absorptiveness (Cobb value) for papers. The highest water absorptiveness of 160.0 g/m2 was observed with a 7.5% Ba treatment in the second recycling stage (75Ba2), indicating a value about 15.6% higher than that of the control. The highest tensile and burst indices were observed with 7.5% Ba treatment in the third recycling stage, indicating approx. 28.7% higher tensile and 34.5% burst indices, compared to the control at similar recycling stages. In contrast, the highest tear strengths of 4.54 Nm2/g, followed by 3.86 Nm2/g, were observed for untreated samples in the second and first recycling stage, respectively. The butylamine treatment in the recycling processes increased the cellulose crystallinity more (1.3%), compared to the control. It seems that the strength properties of recycled paper, such as tensile and burst, are closely related to the individual fiber strength and fiber bonding potential, which are typically reduced in recycling, but could be improved by Ba treatment.

Duplex Detection of Antibiotics in Milk Powder Using Lateral-Flow Assay Based on Surface-Enhanced Raman Spectroscopy

Nowadays, the overuse of antibiotics in cow breeding is a common issue worldwide. Real-time monitoring is critical for antibiotic control of dairy products. Herein, we report a rapid detection method for the duplex detection of two beta-lactam antibiotics (cephalexin and ampicillin) in milk powder using lateral flow (LF) combined with surface-enhanced Raman spectroscopy (SERS). The duplex detection was accomplished using a single test line loaded with two antigens targeting the two corresponding antibody-gold-Raman reporter conjugates. The obtained SERS spectra contributed by the Raman reporter labeled to the two antibodies were analyzed using both peak height method and multiple linear regression (MLR). A good regression fitting was achieved by these two methods (R2 = 0.99 and 0.98, respectively). The limit of detection (LOD) was 10−4 ng/mL for both peak height method and MRL. This study indicated that LF-SERS is a good candidate for real-time multiplex and quantitative analysis for antibiotics in dairy products.

Predicting the redshift on the ultraviolet spectrum using the peak area method.

The ultraviolet (UV) absorption peaks of NaCl, NaOH, and $\beta $β-phenylethylamine (PEA) in an aqueous solution move toward redshift. We proposed the peak area method for the quantitative analysis of PEA, NaCl, and NaOH. First, we obtained the predictable regularities of the redshift of the single component sample. Then, we obtained the regularities of the redshift of the UV spectrum for the mixture by the peak height and peak area methods. Finally, the BP-ANN algorithm was applied to determine the concentration of the mixture using the peak height and peak area method. The results of the testing set showed that correlation coefficients (${{\rm R}^2}$R2) of 0.992, 0.993, and 0.992 were obtained by peak height method and 0.997, 0.998, and 0.998 were obtained by peak area method for NaCl, NaOH, and PEA, respectively. Meanwhile, the relative errors of the prediction of NaCl, NaOH, and PEA obtained by peak area method were less than 3%, whereas the REP of NaCl, NaOH, and PEA obtained by peak height method were more than 5%. Compared with the results of the peak height method, the results showed that the peak area was more accurate than the peak height in predicting the redshift of the UV spectrum.

Pharmaceutical quantification with univariate analysis using transmission Raman spectroscopy

The purpose of this study was to investigate the quantification performance of transmission Raman spectroscopy with univariate analysis. Model dosage forms containing acetaminophen and an excipient, lactose monohydrate, were prepared. The Raman spectra of the tablets were obtained using the modes of transmission, backscattering micro-spectroscopy, and wide area illumination. Calibration curves for quantification of acetaminophen in the tablets were created using peak heights of the Raman spectra. Of the three modes of measurement, the quantitative results by transmission had the highest correlation with those by conventional UV–vis methods. In the validation of quantification by the transmission mode with univariate analysis, a certain degree of daily variation was confirmed. Additionally, quantitative results using peak heights were compared with those of partial least squares (PLSs) multivariate analysis. The root mean square error of prediction (RMSEP) suggested that quantification using PLS provided better precision than the peak height method as expected. However, content uniformity test using large sample sizes by the Raman spectra is not required to be very highly predictive because they usually employ non-parametric criteria and include wide specification ranges. Therefore, univariate analysis using transmission Raman spectroscopy was a suitable quantitative method for conducting content uniformity tests of large sample sizes.

Comparison of sample crystallinity determination methods by X-ray diffraction for challenging cellulose I materials

Cellulose crystallinity assessment is important for optimizing the yield of cellulose products, such as bioethanol. X-ray diffraction is often used for this purpose for its perceived robustness and availability. In this work, the five most common analysis methods (the Segal peak height method and those based on peak fitting and/or amorphous standards) are critically reviewed and compared to two-dimensional Rietveld refinement. A larger ( $$n=16$$ ) and more varied collection of samples than previous studies have presented is used. In particular, samples ( $$n=6$$ ) with low crystallinity and small crystallite sizes are included. A good linear correlation ( $$r^{2} \ge 0.90$$ ) between the five most common methods suggests that they agree on large-scale crystallinity differences between samples. For small crystallinity differences, however, correlation was not seen for samples that were from distinct sample sets. The least-squares fitting using an amorphous standard shows the smallest crystallite size dependence and this method combined with perpendicular transmission geometry also yielded values closest to independently obtained cellulose crystallinity values. On the other hand, these values are too low according to the Rietveld refinement. All analysis methods have weaknesses that should be considered when assessing differences in sample crystallinity.

Cellulose nano-particles from Pandanus: viscometric and crystallographic studies

Pandanus utilis a plant abundant throughout Kerala, India has been used as a source to isolate nano-particles. The fibres were extracted from Pandanus plant by biological natural retting. Extracted fibres were dried, ground and treated with 5 % NaOH followed by bleaching using 5 wt % hypochlorite solution. Bleached cellulose was hydrolysed using sulphuric acid. After centrifugation, suspension was freeze dried. Effect of Acid concentration, temperature and time of hydrolysis on the isolation of cellulose nanoparticles was studied. FESEM images of cellulose showed the presence of spherical nano-particles. Dynamic light scattering revealed homogeneous dispersion of nano-particles. Degree of polymerisation of cellulose was determined viscometrically using cupriethylene-diamine as solvent. Removal of lignin and hemicelluloses was confirmed from FTIR spectra. X-Ray diffractograms of powdered fibre, bleached cellulose and nano-cellulose were compared. Using peak height method and peak de-convolution method, crystallinity indices were determined. Using Scherrer equation crystallite size was calculated and it further confirmed that particles are of nanometre size.

Sensitive method of determination of gold (III) using diacetyl monoxime isonicotinoyl hydrazone (DMIH)

Gold (III) forms a yellow coloured water soluble complex with diacetyl monoxime isonicotinoyl hydrazone (DMIH) reagent in acidic buffer pH 4.5 with λmax at 361 nm. The molar absorptivity and Sandell's sensitivity are 1.50X10 4 L.mol -1 .cm -1 and 0.00333 µg/cm 2 , respectively .The Beer's law validity range is 0.985-11.82 µg/mL. The optimum concentration range is 1.97-9.85 µg/mL. Gold (III) forms (M:L) 1:1 complex with DMIH and stability constant of the complex is 3.263X10 6 . The derivative spectrophotometric determination of Au (III) was carried out by measuring peak height method. The developed derivative spectrophotometric method was employed for the determination of gold (III) in synthetic alloy samples. The effect of various diverse ions was also studied.

Derivative spectrophotometric determination of uranium (VI) using diacetyl monoxime isonicotinoyl hydrazone (DMIH)

Uranium (VI) forms a yellow coloured water soluble complex with diacetyl monoxime isonicotinoyl hydrazone (DMIH) reagent in acidic buffer of pH 3.25 with ?max at 364 nm. The molar absorptivity and sandell’s sensitivity are 1.63 X 10 4 L.mol -1.cm-1 and 0.00307692 µg/cm 2, respectively. The Beer’s law validity range is 1.19–14.28 µg/mL. Uranium (VI) forms (M:L) 1:1 complex with DMIH and stability constant of the complex is 4.928 X 106 .The derivative spectrophotometric determination of U (VI) was carried out by measuring peak height method. The developed derivative spectrophotometric method was employed for the determination of uranium (VI) in rock and synthetic samples. The effect of various diverse ions was also studied.

Derivative Spectrophotometric Determination of Mercury (II) Using Diacetyl Monoxime Isonicotinoyl Hydrazone (DMIH)

Mercury (II) forms a yellow Coloured water soluble complex with Diacetyl Monoxime Isonicotinoyl hydrazone(DMIH) reagent in acidic buffer PH 5.5 with ? max at 351 nm. The molar absorptivity and sandell’s sensitivity are 2.23 X 104 L.mol-1 cm-1 and 0.00225 µg/cm2 respectively. The Beer’s law validity range is1.003 – 12.03 µg/mL. Mercury (II) forms (M:L) 1:1 complex with DMIH and stability constant of the complex is 6.692 X 106. The derivative spectrophotometric determination of Hg (II) was carried out by measuring peak height method. The developed derivative spectrophotometric method was employed for the determination of Mercury (II) in synthetic samples of alloy. The effect of various diverse ions was also studied.

Comparison of established and novel purity tests for the quality control of heparin by means of a set of 177 heparin samples

The widespread occurrence of heparin contaminated with oversulfated chrondroitin sulfate (OSCS) in 2008 initiated a comprehensive revision process of the Pharmacopoeial heparin monographs and stimulated research in analytical techniques for the quality control of heparin. Here, a set of 177 heparin samples from the market in 2008 as well as pure heparin sodium spiked with defined amounts of OSCS and DS were used to evaluate established and novel methods for the quality control of heparin. Besides (1)H nuclear magnetic resonance spectroscopy (NMR), the assessment included two further spectroscopic methods, i.e., attenuated total reflection-infrared spectroscopy (ATR-IR) and Raman spectroscopy, three coagulation assays, i.e., activated partial thromboplastin time (aPTT) performed with both sheep and human plasma and the prothrombin time (PT), and finally two novel purity assays, each consisting of an incubation step with heparinase I followed by either a fluorescence measurement (Inc-PolyH-assay) or by a chromogenic aXa-assay (Inc-aXa-assay). NMR was shown to allow not only sensitive detection, but also quantification of OSCS by using the peak-height method and a response factor determined by calibration. Chemometric evaluation of the NMR, ATR-IR, and Raman spectra by statistical classification techniques turned out to be best with NMR spectra concerning the detection of OSCS. The validity of the aPTT, the current EP assay, could be considerably improved by replacing the sheep plasma by human plasma. In this way, most of the contaminated heparin samples did not meet the novel potency limit of 180IU/mg. However, also more than 50% of the uncontaminated samples had <180IU/MG. In contrast to the aPTT, the PT specifically detects OSCS and other heparin mimetics (LOD 3%). About ten times more sensitive are both the Inc-PolyH-assay and the Inc-aXa-assay, two rapid and simple quantification assays for heparin mimetics. The determined OSCS contents of the heparin samples excellently correlated with those calculated from the NMR spectra. In conclusion, NMR proved to be the current spectroscopic method of choice. The two two-step-assays represent options to supplement NMR, especially as tests for the initial screening, since they detect any heparin mimetic without requiring special expertise for interpretation of the results.

The Influence of Alcohol on the Pharmacokinetics of Antipyrine.

Alcohol-Drug/ Food interaction is a common pharmacokinetic interaction that can cause inter-individual variability in drug kinetics and response by influencing hepatic drug metabolism and related factors. This study was aimed at establishing the influence of alcohol on the pharmacokinetics of antipyrine which has often been used as an index of hepatic metabolizing capacity of the individual tested. Age and sex matched healthy volunteers were chosen respectively as control population (n =12, age = 18-32 years, weight=46-76 kg, males, non alcohol consuming) and study population (n=11, age=18-32 years, males, weight =50-80 kg, alcohol consumption =10-20 g of ethanol per week). Subjects were made to fast for 8 hours before the study. Each was then given 2 tablets of 270mg antipyrine trinitrate to swallow with 200ml of water on an empty stomach. 2 hours later, they were allowed to eat food and drink water. Alcohol ingestion and cigarette smoking were not allowed. Blood samples were then collected from each subject at times 0.25, 0.5, 1.0, 2.0, 3.0, 4.0, 6.0, 8.0, 10.0, 12.0 and 15.0 hours. Plasma antipyrine was extracted by adding methanol, benzoic acid and distilled water to the plasma. The mixture was then centrifuged and filtered. The filtrate was injected into a high pressure liquid chromatography using reversed phase Bondesil C18 (0.5um) column, with benzoic acid (as internal standard) and acetonitrile: acetic acid (in 1% water) (35:65) as mobile phase. The concentrations of the antipyrine were determined from the chromatographic calibration output. The pharmacokinetic parameters of antipyrine in these subjects were compared with control using the Student's “t” test with significance inthe values of the elimination rate constant, elimination half-life, systemic (plasma) clearance, lag time, time to attain peak drug concentration and the area under the drug concentration-time curve (zero to 15 hours and zero to infinity respectively). However, parameters such as absorption half-life, absorption rate constant, the extrapolated plasma drug concentration at zero time, the peak plasma drug concentration and volume of distribution were not significantly different in the two populations (P >0.05). The precision of the method used in the study was checked by manual Peak height (PH) method of quantitation with precision of 1.1- 5.5 %. This study has shown that chronic alcohol ingestion increased the systemic clearance of antipyrine by decreasing its elimination half-life without affecting its absorption from the intestine and its distribution in the body.Key words: Alcohol, drug-food interaction , antipyrine, pharmacokinetics

Quantitative Determination of Hydrate Content of Theophylline Powder by Chemometric X-ray Powder Diffraction Analysis

The purpose of this study was to establish a calibration model to predict the hydrate content in powder materials consisting of anhydrate (theophylline anhydrate (THA)) and theophylline monohydrate (THM) by using various kinds of X-ray powder diffraction (XRPD) analytical methods. XRPD profiles were measured five times each for 11 standard samples containing of THA and THM. THM content in the standard samples was evaluated based on XRPD profiles by the diffraction peak height and area methods, and the Wakelin's and principal component regression (PCR) methods, respectively. Since THA and THM were cube- and rod-shaped particles, the standard samples consisted of THA and THM showed crystal orientation due to THM crystal shape. THA showed reproducible XRPD profiles, but THM showed fluctuating intensities in some specific peaks in the profiles. The linear calibration models were evaluated based on calibration XRPD datasets of the standard materials by various methods. In the result based on validation XRPD datasets, the order of the mean bias and the mean accuracy were peak height > peak area > Wakelin's > PCR, indicating that PCR was the best method to correct sample crystal orientation. The effectiveness of the PCR method in construction of calibration models was discussed by a scientific approach based on regression vectors.

The analysis of dosimetric thermoluminescent glow peak of CaF2:Mn after β-irradiation

The additive dose (AD), Tm(Ea)–Tstop, repeated initial rise (RIR), peak shape (PS) and computerized glow curve deconvolution (CGCD) methods were used to analyze the thermoluminescent (TL) dosimetric glow peak of CaF2:Mn after β-irradiation between the dose level D=0.015Gy and D=110Gy. The PS, Ea–Tstop and CGCD methods indicate that the glow curve is not a single peak but is the superposition of more than one glow peak. The CGCD and Ea–Tstop methods indicate that the dosimetric peak of this material is the superposition of at least five glow peaks, which were referred to as P1–P5. The dose variation experiment indicates that all of them are of first-order kinetics. The activation energies found with the IR and PS methods yield very close values after the cleaning of low temperature satellite peaks from the dosimetric glow peak by increasing the stopping temperature in the Tm–Tstop experiment. On the other hand, there is no agreement between the results of all the applied methods before the application of the Tm–Tstop experiment. The Ea–Tstop plot indicates that the efficiency of thermal quenching effect on this sample is effective above 300°C. This parameter has also pronounced effects on the evaluated kinetic parameters of the dosimetric peak. The influence of heating rates on the response of dosimetric glow peak of CaF2:Mn was also studied by the peak height and peak area methods using CGCD technique. It was observed that the peak intensities and total area of glow peak decrease continuously with increasing heating rate. Another dosimetric characteristic which is the dose response of this peak was also examined by peak height and area methods.

Microfibril angle variability in Masson Pine (Pinus massoniana Lamb.) using X-ray diffraction

The microfibril angle of fiber walls is an ultra-microscopic feature affecting the performance of wood products. It is therefore essential to get more definitive information to improve selection and utilization. X-ray diffraction is a rapid method for measuring microfibril angles. In this paper, the variability of microfibril angle in plantation-grown Masson pine was investigated by peak-fitting method. This method was compared with the traditional hand-drawn method, 40% peak height method and half peak height method. X-ray diffraction measurements indicated that the microfibril angle changed as a function of the position in the tree. The mean microfibril angle decreased more gradually as the distance increased from the pith and reached the same level in mature wood. The microfibril angle also seemed to decrease clearly from the base upward. Differences of angle-intensity curves between heartwood and sapwood were also examined.