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The luminescence properties of natural white fluorite indicate that it could be employed as radiation dosimeter similarly to synthetic CaF 2 :Mn (TLD-400). The cathodoluminescence emission of the natural sample (two maxima) meanwhile TLD-400 (one peak) exhibits a different behaviour associated with the chemical composition. The mineral sample displays (i) a significant UV-blue emission associated with different structural defects (negligible in the synthetic sample) and (ii) a shift of the green emission to higher wavelengths respect to the TLD-400. The green induced TL emission also shows significant differences in intensity (higher in TLD-400) and sensitivity. Both samples display a complex induced green TL glow curve that could not be analysed assuming the model based on the discrete trap distribution. The T m – T stop method indicates the presence of close overlapping groups of components linked probably to a continuum in the trap distribution rather than a single trapping level. [ABSTRACT FROM AUTHOR]

In this article, we have investigated the effects of pre-irradiation heat treatments on the thermoluminescence (TL) glow peaks of natural fluorite (CaF2) collected from the central Anatolia region of Turkey. A typical TL glow curve of phosphor consists of four clear glow peaks with maximum intensities occurring at temperatures around 100 °C, 120 °C, 190 °C and 290 °C for a sample irradiated to a dose of 48 Gy and readout at a heating rate of 1 °C/s. It was observed that the intensities of all the TL glow peaks are strongly sensitive to annealing temperatures and durations. Annealing at 450 °C for 15 min was found to be the best for reproducibility of experimental results. The dose-responses of individual TL peaks of this material were also examined after annealing at 450 °C for 15 min by β-irradiation to doses between 0.04 Gy and ≈10.4 kGy. It was observed that the total area and peak heights of all glow peaks showed similar trends with increasing radiation dose; first, they increased linearly up to ≈50 Gy and then saturation effects began above this dose value. The effect of heating rate on the TL glow peaks of the mineral was also studied and it was observed that the intensities of glow peaks are differently affected with variation in heating rate. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the thermoluminescence (TL) properties of natural CaF2 were investigated after β-irradiation at room temperature (RT). The additive dose (AD), T m(E a)–T stop, repeated initial rise (RIR), and computerized glow curve deconvolution (CGCD) methods were used to analyze the thermoluminescence (TL) glow peaks in natural CaF2 after β-irradiation between 0.015Gy and ≈2kGy dose level. These methods were used to determine the number of peaks and kinetic parameters (kinetic orders b, activation energy E a, and attempt-to-escape frequency s) associated with the thermoluminescence (TL) glow peaks of natural CaF2. The E a–T stop and CGCD methods indicate that the glow curve of this material is the superposition of at least six glow peaks, which were dealt with as P1–P6, in the temperature range between room temperature (RT) and 400°C. Dose variation experiments revealed that TL glow curve of natural CaF2 has both first and general-order glow peaks. The dose responses and fading process, which are very useful in radiation dosimetry, of individual TL peaks of this material were also examined. In addition, the influence of heating rates on the response of dosimetric glow peaks of natural CaF2 was studied. It was observed that the total area of glow peak and peak intensities of all glow peaks are continuously decreasing with increasing heating rate. [Copyright &y& Elsevier]

• NaBaBO 3 :Ce3+ phosphor is synthesized by a combustion method. • Thermoluminescence properties were conducted. • Activation energies were calculated using IR, Booth-Bohun-Parfianovitch, VHR and CGCD methods. NaBaBO 3 samples incorporated with various concentration of Ce3+ were prepared by combustion method. The influences of rare earth doping in synthesized samples were analyzed by X-ray diffraction (XRD). Optimum doping concentration of NaBaBO 3 :Ce3+ is 0.5 %. Thermoluminescence (TL) kinetic analysis using T m -T stop , initial rise (IR), variable heating rate (VHR) and glow curve deconvolution (GCD) methods were performed on the glow curves of NaBaBO 3 :Ce3+ phosphor material. The T m -T stop analysis revealed that the whole glow curve measured without preheat of the prepared sample is composed of at least six overlapping glow peaks. The number of the glow peaks required to provide best fit to the glow curves of the sample are also estimated using GCD method and one found six glow peaks at all doses (FOM ≤ 1.84 %), which are similar to those from T m -T stop analysis. The dose response of NaBaBO 3 :Ce3+ phosphor sample exposed to beta irradiation is linear up to 10 Gy. The results from experiments indicates that main dosimetric peak of NaBaBO 3 :Ce3+ follows first order kinetic model, which was also supported by dose response plot. The Z effective value of this phosphor is calculated to be 46.66. Present findings confirm that NaBaBO 3 :Ce3+ phosphor sample is a promising candidate for applications in environmental dosimetry as one depicts good TL dose response with adequate sensitivity and linearity. [ABSTRACT FROM AUTHOR]

In the present work, the thermoluminescence (TL) properties and kinetics of beta‐irradiated porcelain used as an electrical insulator are investigated in great depth. Thermal annealing at 1100°C slightly changes the trap system, whereas heating over 500°C increases the visual TL intensity of the peaks. X‐ray diffraction, scanning electron microscopy with energy dispersive X‐ray spectroscopy, atomic absorption spectroscopy, and Fourier transform infrared spectroscopy were used to confirm the structural, morphological, and chemical investigations of the materials. The TL glow curve characteristics, repeatability, storage time properties, and dose–response behavior of non‐annealed and annealed porcelain have all been well investigated. Within the confidence interval, the material has been demonstrated to have excellent reusability. A linear response in the dose range of 0.1–3 Gy was observed. TM–Ts, initial rise, and computerized glow curve deconvolution methodologies were used to complete the kinetic study. The outcomes of the detailed investigations demonstrated that the sample was suitable for TL dosimetry potential uses. [ABSTRACT FROM AUTHOR]

This review is concerned with some key features observed within grouped samples of ancient ceramics that provide important evidence concerning the selection of appropriate raw materials and the evolution of the firing technologies employed in their production. It also demonstrates the importance of distinguishing and accounting for the mineralogical and microstructural attributes and identifying the processes responsible for the microstructural evolution of these ancient ceramics. The mineralogy largely reflects both the nature of the raw materials used and the maximum temperatures achieved during firing, deduced from the presence of specific high temperature minerals (HTMs). The microstructural evolution processes, deduced by the micromorphology of these ancient ceramics and displayed in specific features, observed in both the matrix and the slip of these ceramics, are largely controlled by the firing methods used in manufacturing. Thus, we conclude that the application of micromorphological principles, methods, and observations derived from the broad sphere of "pedology" to the study of ancient ceramics, provides valuable insights into the independent evolution of ceramic production methods in ancient societies. Thus, most of the observations recorded here concern identification of the raw materials used to make ancient ceramics and the firing processes used in their manufacture. Our data demonstrate that these ancient potters made use of a variety of temper materials (quartz and chaff, together with fragments of locally available rocks and minerals) that are now preserved in the matrix. Furthermore, analyses of the micromorphological attributes displayed by these ancient ceramics are helpful in determining and explaining the shrinkage features (stress coatings or poro-striated b-fabrics) and the preferred orientation of the elongated pores that have developed after firing in poorly controlled and slow-fired furnaces. In this regard, we finally seek to develop a useful data library ultimately targeting the enhancement of simulated ancient ceramic/pottery production, with an overall objective to apply the mineralogical and pedological properties of Anatolian ceramics researched in this work to globally selected shard specimens. Postburial processes, such as the illuviation-deposition of clay minerals to form the observed clay coatings, probably operated during the wet-dry cycles associated with mid-late Holocene climatic fluctuations. Accompanying calcification-decalcification processes, which may result from an intra cramic leaching-deposition of carbonate present in the source material of the pottery, are also consistent with the known wet-dry cycles of the mid to late Holocene pedogenesis (soil formation) episode and is reflected in the clay coatings and further attested by coeval changes in the soil-faunal activity. [ABSTRACT FROM AUTHOR]

Abstract: One of the most important mineral in dosimetric investigation is quartz, which is found abundantly in archaeological and geological materials. Although there are many studies about its thermoluminescence (TL) properties in the literature, it may exhibit different properties for each quartz mineral extracted from the different region of the world. In the present work, the stabilities and dose responses of glow peaks of quartz obtained from the tiles of Kubad Abad Palace in central Turkey were investigated after annealing at 500 and 600°C for 1h. The variation of radiation sensitivity of TL peaks of the quartz grains extracted from tiles are found to be more stable after annealing at 600°C than 500°C for 1h. The TL dose responses of glow peaks of annealed and unannealed quartz samples were also studied up to approximately 3kGy. It was observed that the pre-irradiation heat treatments affect the dose response behaviors of glow peaks. [Copyright &y& Elsevier]

The 45-km-long, E-W to NW-SE-striking Manisa Fault Zone, which constitutes the western section of the Gediz Graben, is characterized by a pure normal sense of motion with a minor strike-slip component. Even though there are numerous historical earthquakes have been listed in Western Anatolia Graben System, a few studies have been addressed on seismic sources of the earthquakes so far. According to existing literature, the western segment of the Manisa Fault Zone is well known characterized; however, the eastern segment of it has rarely been addressed. To decipher the Holocene seismotectonic behavior of the eastern segment of Manisa Fault Zone, trench-based paleoseismological analyses for the first time were performed along with it. To constrain the timing and frequency of past earthquakes, and elapse time from the last activation using the optically stimulated luminescence (OSL) and radiocarbon (14C) dating, we collected twenty-six colluvial and paleosol samples from the trenches. The obtained paleoseismic data show that (i) Manisa Fault Zone is responsible for six surface rupturing earthquakes since late Pleistocene-Holocene, which is occurred at 30.6 ± 8.8 ka (E1), 15.0 ± 5.0 ka (E2), 6.6 ± 1.3 ka (E3), 2.9 ± 1.3 ka (E4), 0.8 ± 0.4 ka (E5), and 0.1 ± 0.1 ka (E6), (ii) the recurrences interval of destructive earthquakes on Manisa Fault Zone was found between 0.95 kyr to 3.8 kyr for Holocene, and (iii) the elapsed time since the most recent surface ruptured earthquake on the Manisa Fault Zone is 159 year. [ABSTRACT FROM AUTHOR]

In the present study, the precipitation method was used to synthesize microcrystalline Nd-doped CaSO 4 phosphor. Structural and morphological analysis of the phosphor samples were performed by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. In addition, luminescent properties of the samples were characterized by thermoluminescence (TL) and optically stimulated luminescence (OSL) methods. The results of XRD analysis and SEM images showed that the prepared CaSO 4 :Nd powder samples have an orthorhombic crystal structure and almost spherical in size with an average between 3 and 17 μm. In the light of the luminescence analysis, the optimum preheat temperature required to evacuate the low temperature electron traps was determined as 170 °C. It was also presented that CaSO 4 :Nd samples have the potential to be used as a dosimetric material with a linear dose sensitivity between 1 and 20 Gy (as TL dosimeter), and 1 and 10 Gy (as an OSL dosimeter) when they are exposed to beta irradiation. In addition, the full width at the half maximum (FWHM) values of the main TL peaks presented no independence of HR. • Nd-doped CaSO 4 phosphors were synthesized by using the precipitation method. • Structural, morphological and luminescent properties of CaSO 4 :Nd were determined. • CaSO 4 :Nd is almost spherical in size with an average particle size in the range of 3–17 μm. • CaSO 4 :Nd samples have a linear dose sensitivity between 1 and 20 Gy (as TL dosimeter) for beta irradiation. [ABSTRACT FROM AUTHOR]

Abstract NaBaBO 3 host material was synthesized using the combustion method. In order to optimize the performance of the material, effects of sintering temperatures varying from 600° to 1000 °C were investigated. The sintering temperature and dwell time were found to have pronounced effects on the pure NaBaBO 3 material. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) techniques were used to confirm the phase formation and examine the surface morphology of the prepared powder material, respectively. TL behavior of NaBaBO 3 was studied at various beta doses. It is seen that the sample exhibits well resolved TL glow peak at a peak temperature about 175 °C and corresponding TL intensity increases with the increasing beta dose. However, TL glow peak slightly shifts to lower temperature with the increasing beta dose level. This is the first TL report of a phosphor with a NaBaBO 3 host. The TL kinetic parameters were estimated by the peak shape (PS) method and CGCD software. TL glow curves of NaBaBO 3 consist of several traps and exhibited second order kinetics. A possible TL mechanism was also discussed using the energy level model. The obtained results can provide valuable knowledge related to the investigation of the intrinsic nature characteristics of NaBaBO 3 in research fields pertaining to dosimetry. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the effect of different heating rates (HRs) on low and high temperature thermoluminescence (TL) glow-peaks, reusability properties, and the kinetic parameters (activation energy ( E ), frequency factor ( s ) and order of kinetics ( b )) of 1%, 4% and 10% La-doped ZnB 2 O 4 phosphors. All La-doped ZnB 2 O 4 phosphors have two characteristic TL peaks at around 80–85 °C and 150–160 °C. The experimental results show that the TL glow-peak temperatures (T M ) shift to higher temperatures for all doped materials as the HRs increase because of the temperature lag effect. The maximum peak intensity ( I M ) decreases for the first peak of 1% doped, remains roughly constant for second peak of 1% and both peaks of 4% doped, and increases for both peaks of 10% La-doped ZnB 2 O 4 samples as the HRs increases. Differences between the intensities of various amounts of La-doped phosphors were explained with anomalous HR phenomenon except the first peak of 1% La-doped ZnB 2 O 4 which was clarified by thermal quenching effect. In this study, the temperature dependence of the recombination rate of released carriers during the heating process by increasing the doping concentration of La might explain the peaks of the glow curves, which shows an unexpected behavior with the increasing HR values. In addition, the calculated E values of all doped phosphors were found similar in the range of 0.62 – 1.03 eV for 1%, 0.65 – 1.15 eV for 4%, and 0.69 – 1.01 eV for 10% La-doped phosphors. However, s values were found slightly different related to the dopant amount. Furthermore, different dopant amounts indicate the similar and reasonable properties for the repeated cycles of 5 Gy with the same readout conditions. [ABSTRACT FROM AUTHOR]

The effect of heating rate (HR) on thermoluminescence (TL) glow curves of 1%, 4%, and 10% Ce 3 + doped ZnB 2 O 4 phosphors was investigated in detail. The glow peaks are examined and, activation energy ( E ) and frequency factor ( s ) are determined by using various heating rate (VHR) method. In the obtained glow curves with nine different HRs between 2 and 10 °C/s, it was observed that the TL intensities of the first peaks of all three samples and the second peak of 10% Ce 3 + doped sample decrease with increasing HR. The decrease in TL intensity was investigated whether it may be due to the presence of thermal quenching or not. On the other hand, the second glow peaks of 1, 4% Ce 3 + doped ZnB 2 O 4 phosphors show an anomalous TL behavior, which the probability of the radiative processes increases due to recombination of free electrons, so the TL intensity increases with the HR. The graphs of full width at the half maximum (FWHM) versus HR were also plotted to evaluate the influence of HR on TL intensity. In this paper, we suggest that the non-localized Schön – Klasens model may give an explanation for the second peaks of 1, 4% Ce 3 + doped ZnB 2 O 4 phosphors showing an unexpected increase with the increasing HR. In addition, the calculated E values of all doped phosphors were found similar in the range of 0.47–0.53 eV for peak 1 and 0.61–0.66 eV for peak 2. However, s values of Ce 3 + doped ZnB 2 O 4 phosphors were found slightly different according to the dopant amount and the equation used. Furthermore, different amount of Ce 3 + doped samples indicate the similar properties for the repeated cycles of 5 Gy in the same irradiation conditions. [ABSTRACT FROM AUTHOR]

The kinetic parameters of 1%, 2%, 3% and 4% La-doped ZnB 2 O 4 phosphors (i.e. ZnB 2 O 4 :0.01La, ZnB 2 O 4 :0.02La, ZnB 2 O 4 :0.03La and ZnB 2 O 4 :0.04La) synthesized by nitric acid method have been calculated. Thermoluminescence (TL) glow curves of ZnB 2 O 4 :La phosphors after beta-irradiation showed a very well defined main peak having the maximum temperature at around 200 °C and a shoulder peak at around 315 °C with a constant heating rate of 5 °C/s. The kinetic parameters of ZnB 2 O 4 :La phosphors TL glow peaks (i.e. order of kinetics ( b ), activation energies ( E a ) and frequency factors ( s )) have been determined and evaluated by Computerized Glow Curve Deconvolution (CGCD), and Peak Shape (PS) methods using the glow curve data. From the results, it can conclude that the values of E a obtained with these methods for ZnB 2 O 4 :La phosphors are consistent with each other, but the s values differ considerably. [ABSTRACT FROM AUTHOR]

In this study, the optically stimulated luminescence dating technique was used to determine the time of deposition of alluvial sediment samples from the Türkoğlu-Antakya segment of the East Anatolian Fault System (EAFS) in Turkey. The double-single aliquot regenerative dose protocol on fine grain samples was used to estimate equivalent doses (De). Annual dose rate was computed using elemental concentration of uranium (U) and thorium (Th) determined by using thick-source alpha counting and potassium (K) concentrations using X-ray fluorescence and/or atomic absorption spectroscopy. The environmental dose was measuredin situusing α-Al2O3:C chips inside plastic tubes for a year. The two different bulk sediment samples collected from the Islahiye trench yielded ages of 4.54 ± 0.28 and 2.91 ± 0.23 ka. We also obtained a 2.60 ± 0.18 ka age for the alluvial deposit in the Kıranyurdu trench and 2.31 ± 0.14 ka age for an excavation area called Malzeme Ocağı. These ages were consistent with the corresponding calibrated Carbon-14 (14C) ages of the region. The differences between the determined ages were insufficient to clearly distinguish the disturbance event from the effects of bioturbation, biological mixing, or other sources ofDevariation in the region. They provide a record of alluvial aggradation in the region and may determine undocumented historical earthquake events. [ABSTRACT FROM PUBLISHER]

In this study, the thermoluminesce (TL) properties of natural onyx were determined after β-irradiation ( 9 0 Sr/ 90 Y) at room temperature. The effect of the additive dose and variable heating rate for TL glow peaks of the sample were investigated. Computerized glow curve deconvolution (CGCD) methods were used to determine the number of peaks and kinetic parameters related to the TL glow peaks in natural onyx from Turkey. It was also determined kinetic parameters of onyx by means of the variable heating rate (VHR) method. The sample was exposed to β-irradiation between 2.4 Gy and 2.457 kGy. The CGCD methods showed that the glow curve of sample is the superposition of at least six first order components which were ascribed as P1-P6. The dose responses of some peaks have similar patterns and they follow linearity. The effect of heating rates on the response of dosimetric glow peaks of sample was studied. The maximum TL peak intensities of glow curve are decreasing with increasing heating rate and maximum TL peak intensities at 1 °C/s drops to 20% of the initial value when the sample is read at 6 °C/s. [ABSTRACT FROM AUTHOR]

We have worked on the structural and magnetic properties of ZnMnGdO(for x = 0.02, 0.03, and 0.04) compounds prepared by using a sol-gel method. The x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy were used to understand the structural properties of the samples. We observed that co-substitution of Mn (1 %) and Gd (2-4 %) into the ZnO does not change the hexagonal structure. Scanning electron microscope (SEM) images show us that the grain size decreases with the increasing amount of the Gd into the ZnO matrix. The magnetic properties of the samples have been investigated by using magnetic hysteresis and DC susceptibility measurements. The ZMG1 sample shows a weak ferromagnetic behavior at room temperature, whereas the ZMG2 and ZMG3 samples exhibit a paramagnetic nature. Furthermore, it is also found that the magnetizations of the samples decrease with increasing Gd content in the ZnMnO system due to the enhancing interaction between Gd ions. We summarize that the co-substitution of Mn and Gd into the ZnO generates a room-temperature ferromagnetism, but it still needs more work to obtain strong and high coercivity magnetic loops for applications. [ABSTRACT FROM AUTHOR]

Dolomite is a carbonate mineral of calcium and magnesium having the chemical formula CaMg(CO 3) 2. It is a reservoir for significant petroleum reserves and mainly used as building and ceramic material. Thermoluminescence (TL) emission of this mineral has been examined in the literature, especially collected from Egypt, India, and Brazil. In this study, the aim is to investigate TL properties of dolomite mineral which has a wide reserve in Mersin/Turkey. Structural, morphological, and elemental analyzes were performed by X-ray Diffraction (XRD) Spectroscopy, Scanning Electron Microscope equipped with Energy Dispersive X-ray Spectrometer (SEM-EDS), and Inductively Coupled Plasma Mass Spectrometer (ICP/MS), respectively. TL measurements were carried out using a TL/OSL reader with a90Sr/90Y beta source. The natural TL (NTL) curve of the sample showed two peaks at around 255 and 345 °C by the wideband blue filter whereas an additional peak at 115 °C was observed under the beta irradiation. In addition, at high doses from 50 Gy, a shoulder at around 402 °C occurred. The optimum annealing temperature and duration of the sample were determined as 500 °C and 30 min. In order to remove the low-temperature peak, a preheating process at 200 °C with 23 s duration was applied before each TL readout. TL response to absorbed dose showed good linearity over the 0.1–1200 Gy dose range and the sample was observed to be reusable with only 1.7% change up to 10 cycles under a dose of 100 Gy. The kinetic parameters (activation energy E (eV), frequency factor s (s−1), kinetic order b) of the evident glow peaks were estimated using Peak Shape (PS), Various Heating Rate (VHR), Initial Rise (IR), and Computerized Glow Curve Deconvolution (CGCD) methods. The kinetic analysis indicated that the TL glow curve of the preheated sample consists of four individual peaks having activation energies of ∼1.56, 1.60, 1.78, and 1.73 eV, and these peaks obey second and general-order kinetics. • TL character of natural dolomite mineral originating in Turkey was investigated. • TL glow curve of the β-irradiated sample exhibited three peaks at 110, 255, and 345 °C and a shoulder at 402 °C at high doses. • The sample shows a good linear TL response in the 0.1–1200 Gy β-dose range. • The sample can be reused up to 10 sequential cycles with the deviation of 1.7%. • TL kinetic analyses revealed the decomposed peaks have second- and general-order kinetics. [ABSTRACT FROM AUTHOR]

The Fertile Crescent of the Middle East region, embracing Syria, eastern Turkey and Iraq, marks the region where settled agriculture began, and where the landscape has been shaped for millennia by human activities. The lacustrine and fluvial terraces of the Late Pleistocene and Holocene Eras are common geomorphic features in many areas around Lake Van in eastern Turkey, being sustainably used since the Urartian Period (800–400 yearsbc). Fluctuations in the water levels of Lake Van have resulted in the development of widely distributed natural terraces around the Lake. The undulating slopes of these terraces have limited their cultivation, however, leading people to reconstruct terraces as a means for utilizing particular production sites, as anthroscapes (this concept is generally confined to situations where marked differences or deviations from the normal, natural landscapes are attributable to effects/shaping by humans). The region exhibits semiarid climatic conditions and a short crop-growing season, currently being under the threat of land degradation. Recent mismanagement of these lands as a result of increasing population pressures has led to the degradation of both the natural and the man-made terraces. Thus, there is an urgent need to conserve and understand the indigenous management and soil quality attributes of these man-made terraces. To this end, this study examined soil profiles and analysed soil samples for their chemical, physical and mineralogical characteristics, in order to determine the human effects of leaching and/or accumulation. These analyses revealed significant differences between the physical, chemical, microbiological and mineralogical properties of the man-made/reworked terraces and natural terraces under essentially similar parent materials and environment, thereby providing clues as to the sustainable management of these land surfaces in eastern Turkey. The approaches used in this study provide useful evidence for attempting to explain the historical evolution of land use in similar environments elsewhere, as well as the significance of terraces in combating coastal erosion in lake environments. [ABSTRACT FROM AUTHOR]

Abstract: The additive dose (AD), T m(E a)–T stop, repeated initial rise (RIR), peak shape (PS) and computerized glow curve deconvolution (CGCD) methods were used to analyze the thermoluminescence (TL) glow peaks in natural zircon after β-irradiation between the dose level 0.015Gy and ≈10kGy. The CGCD and E a–T stop methods indicate that the glow curve of this material is the superposition of at least seven glow peaks, which were referred to as P1–P7, in the temperature range between room temperature (RT) and 400°C. The dose responses and fading process of individual TL peaks of this material were also examined. The dose response behaviors of all peaks are different from each other and they are saturated at different dose levels. Peaks 1 and 2 completely disappeared after 1 month storage in the dark room at RT. On the other hand, the intensity of peaks 3+4 was approximately reduced to 80% of its original value whereas the other peaks (P5–P7) were not sufficiently affected during this period. [Copyright &y& Elsevier]