External Radiations Research Articles

Tunable Second Harmonic Generation with Large Enhancement in A Nonlocal All‐Dielectric Metasurface Over A Broad Spectral Range

AbstractRecently, all‐dielectric metasurfaces are profoundly exploited to enhance light‐matter interactions, resulting from the high quality‐factor (Q‐factor) optical resonances that based on novel concepts such as the bound states in the continuum (BIC). Unfortunately, BIC operates at a fixed resonance wavelength and a fixed wavevector for a specific structure. Here, the experimental demonstration of a dielectric nonlocal metasurface capable of robustly maintaining high‐Q resonances is reported, over a broad spectral range, where the specific wavelength is selected by controlling the incident angle. This is enabled by steering infinite‐Q guided modes (GMs) in subwavelength lattices into quasi‐GMs (QGMs), which are accessible by external radiations while retaining the same dispersion as the GMs. Such invaluable characteristics are achieved by harnessing the period‐doubling perturbation, implemented in a nonlocal metasurface structure on top of a lithium niobate (LN) film. Furthermore, spectrally tunable second‐harmonic generations are demonstrated in this structure with an enhancement factor of ≈1200 compare to that of a bare LN film of the same thickness over a large bandwidth. These results suggest that the QGMs supported by all‐dielectric nonlocal metasurfaces provide an excellent platform for enhancing light‐matter interactions with additional desired functionalities of spectral tunability and random selection of the operation wavelength.

Revision of the 21909 standard on passive personal neutron dosemeters.

Since 2012, International Standardization Organization TC85/SC2 Working Group 19 dealing with 'Individual monitoring for external radiations' has been conducting important work revising the 21909 standard on passive personal neutron dosemeters. A consensus in the community acted that the 2005 version( 1) needed to be revised for two main reasons: (1) to achieve a document applicable to all systems irrespectively to the considered techniques and (2) to reach harmonisation between performance tests and conditions of use at the workplaces. The document was completely rewritten to be binding enough to ensure that any neutron dosimetry system fulfilling the criteria would be reliable in most of the usual work situations, in terms of dose level, energy and direction distributions of the neutron fluence. This paper explains the reasons behind the revision and the new philosophy of the series published in 2021, so that Individual Monitoring Services may better understand how to apply the requirements in practice.

THU020 Bilateral Adrenal Hyperplasia (BAH): Undesirable Effect Of Glucocorticoid Receptor Competitive Antagonist (GRCAnt) In Cushing’s Disease

Abstract Disclosure: A. Canturk: None. C. Villabona: None. A. Kargi: None. We present a case of a complicated ACTH (adrenocorticotropic hormone)-dependent tumor and hypercortisolism, we discuss the potential side effects of mifepristone, a GRCAnt potentially causing bilateral adrenal hyperplasia and we discuss potential pathophysiologic mechanisms. This is a 73 years old male who presents to the clinic for a follow-up of Cushing’s Disease (CD). He has a pmh of osteoporosis, hypopituitarism, and secondary DM in the setting of an aggressive and medication-resistant Corticotroph Pituitary Neuroendocrine Tumor (cPNET). He has undergone a total of four transsphenoidal surgeries since 2013 and two treatments with external beam radiations. He still has residual tissue invading his cavernous sinus, thus another surgery was not an option, so Gamma Knife (GK) therapy was given. In the past, he has received a trial of ketoconazole for a period of 2-3 years, temozolomide, and octreotide, and is currently on mifepristone for the past four years. He underwent Bilateral Adrenalectomy in 2016 and had a small adrenal residual. It is demonstrated in a PET scan from 2018 that he had BAH and confirmed in a recent CT abdomen on 12/2022. While on mifepristone his ACTH was 1173pg/mL (nl:10 and 60 pg/mL), and cortisol 92.7 mcg/dL (nl:5 to 25 mcg/dL). Cortisol urine was 1627.2 mcg/24hr (nl:4 to 40 mcg/24hr). For treatment of his cPNET, we discontinued mifepristone and started on ketoconazole, and referred him to surgery for a second adrenalectomy. We reordered IHC on pathology specimens obtained in 2019 for SSTRs 1-5 and might consider starting synthetic somatostatin analog. We illustrate the potential negative effect of the long-term use of mifepristone. This is a GRCAnt that increases ACTH levels (8-10 fold in some cases) and will potentially cause BAH. This is an aggressive cPNET with hypercortisolism, who has been on long-standing medical therapy with mifepristone. He has developed BAH which has been potentially caused or exacerbated by GRCAnt. Reviewing the literature, there is limited data on this topic. This effect appears not to occur in all patients with Cushing’s disease. We propose potential pathophysiologic mechanisms of the indirect or direct effect of mifepristone causing BAH and potential factors explaining why this phenomenon might only occur in selected patients, we also propose management of patients on long therapy with GRCAnts. Presentation: Thursday, June 15, 2023

Measurements of Radiometric Concentrations for <sup>222</sup>Ra, <sup>238</sup>U, <sup>232</sup>Th and <sup>40</sup>K in Soil Samples from Two Uranium Mines’ Stockpiles, Erongo Region, Namibia

<p>The continuous exposures from radiations to human population has led to research studies on evaluating the radioactivity concentrations in most parts of the world. Naturally occurring radioactive materials (NORM) have been greatly regarded as the chief sources of both terrestrial and cosmological radiations. In this study a high-purity germanium well detector was used to measure the activity concentrations of samples from mines 1 and 2 considered in the study. The measured average activity concentration for <sup>226</sup>Ra, <sup>238</sup>U, <sup>232</sup>Th and <sup>40</sup>K in mine 1 were estimated at 2546±10, 557±13, 215±2 and 1079±26 Bq.kg<sup>-1</sup>, respectively. For mine 2, the estimated average values of the radionuclides of <sup>226</sup>Ra, <sup>238</sup>U, <sup>232</sup>Th and <sup>40</sup>K were calculated as 4414±27, 842±29, 436±5 and 2225±52 Bq.kg<sup>-1</sup>, respectively. The high concentration of radium in samples contributed to high rate of radon emanation into the atmosphere, ground and surface water as well and, if no remedial measures are put in place, this may contribute to plants, animals and eventually human exposures in the region. The study concludes that mine tailings contribute to an increase in background radiation in the environment due to the fact that they are uncovered and deposited in the open environment, resulting in wind-blown <sup>226</sup>Ra carrying dust entering nearby residential dwellings. The exposures rates could also be increased by other possible transfer pathways, such as ingestions, inhalations and external gamma radiations. Mining companies are urged to decrease windblown atmospheric exposure by using water tanks mounted on mining equipment to sprinkle on top of the soil or covering the tailings with canvas sheet.</p>

The The Relationship Of Nurse’s Effective Communication Patterns To Anxiety Level Among Carcinoma Patients Undergoing External Radiotherapy At Adi Husada Cancer Center Surabaya

Introduction: Anxiety is a common problem experience by cancer patient undergoing external radiotherapy causes physical and psychological factors. Anxiety can worsen the patient’s condition because anxiety reduce immune system by lower activity of T lymphocyte cells as natural killer cells, so it can make increase the growth of malignant cells. Treatment for cancer patients is often only focused on physical factors, while the patient’s psychological factor is sometimes neglected. One way that can be used to reduce the patient's psychological anxiety is use communication effectively. However, the relationship of nurse’s effective communication patterns to anxiety level among carcinoma patients undergoing external radiations therapy is not yet clear.
 Methods: A correlation analytic approach with cross sectional design to analyze the relationship between nurse communication and patient anxiety level. This research was conducted on 40 respondents carcinoma undergoing external radiations therapy on August-September 2021. Subjects were chosen using purposive sampling.
 Result: The data were analyzed using spearman rank test. The data shows not significant figures or numbers p-value= 0.329 > α (0.05). Implementing effective communication among patients carcinoma undergoing radiotherapy can’t reduce the patient's anxiety level.
 Discussion: Effective communication can help clients clarify the burden of feelings and thoughts, get the information needed, feeling heard, feeling cared so that it can reduce the client's anxiety. But in this study, factor can affect anxiety level in patient cancer undergoing radiotherapy are age of patients, background education, cancer stage, length of cancer, social support, financing, sources of information and role change.

Experimental study of the horizontal subsurface flow trajectory and dynamic external radiation of flame spread over diesel

In the process of production, transportation and storage of liquid fuel, accidental leaked liquid fuel could cause the flame spread, which may eventually lead to a serious fire accident. Therefore, it is imperative to study the characteristics of flame spread. Experiments of flame spread was conducted with eight-size pools whose width ranges from 4 to 25 cm. Results indicated that with pool width increasing, the time difference between the subsurface flow passing the pool centerline and the pool sidewall firstly decreases and then keeps constant. Sidewall viscous force and liquid surface tension exit a competitive relationship to affect the subsurface flow. As pool width increases, the changeable dominant areas of sidewall viscous force and liquid surface tension can control horizontal subsurface flow trajectory. In addition, the whole spreading flame shape is assumed as n radiation points. External radiations of the flame that crosses and does not cross the center point of pool long side are calculated after or before some time. The aspect ratio of the small flame is found to be gradually reduced to thicken the density of point sources with the flame spread development. Finally, a dynamic external radiation model of flame spread is established at different moments.

Mass Spectrometry-Based Method for the Determination of the Biodistribution of Tumor-Targeting Small Molecule-Metal Conjugates.

Nuclear medicine plays a key role in modern diagnosis and cancer therapy. The development of tumor-targeting radionuclide conjugates (also named small molecule-radio conjugates (SMRCs)) represents a significant improvement over the clinical use of metabolic radiotracers (e.g., [18F]-fluorodeoxyglucose) for imaging and over the application of biocidal external beam radiations for therapy. During the discovery of SMRCs, molecular candidates must be carefully evaluated typically by performing biodistribution assays in preclinical tumor models. Quantification methodologies based on radioactive counts are typically demanding due to safety concerns, availability of radioactive materials, and infrastructures. In this article, we report the development of a mass spectrometry (MS)-based method for the detection and quantification of small molecule-metal conjugates (SMMCs) as cold surrogates of SMRCs. We applied this methodology for the evaluation of the biodistribution of a particular class of tumor-targeting drug candidates based on natLu, natGa, and natF and directed against fibroblast activation protein (FAP). The reliability of the liquid chromatography-MS (LC-MS) analysis was validated by a direct comparison of MS-based and radioactivity-based biodistribution data. The results show that MS biodistribution of stable isotope metal conjugates is an orthogonal tool for the preclinical characterization of different classes of radiopharmaceuticals.

The prediction of the inside temperature and relative humidity of a greenhouse using ANN method with limited environmental and meteorological data

In this paper, the prediction of the internal temperature (Tin) and relative humidity (Rhin) of a greenhouse located near Agadir, Morocco using artificial neural net-work (ANN) as machine learning method. First, an analyze of correlations be-tween inputs and outputs is studied in order to select the adequate input parameters. External temperature, relative humidity and solar radiations were the parameters that have the highest correlation coefficient with the outputs. They are thus selected as the only input parameters. The prediction of Tin and Rhin with the previously cited inputs gives a perfect coefficient of correlation (R=0.996). The aim of this study is to use only one measured input parameter (external temperature) and eliminate the two environmental parameters (relative humidity and solar radiation), by introducing the factor of time as input of the ANN model. Results were very satisfying and 20 neurons was sufficient to reach a correlation of about 0.98.

Metallic Nanopopcorns: A New Multimodal Approach for Theranostics

Background: Nanopopcorns are a novel class of metallic nanoparticles that demonstrate structural similarity to the grains of popcorns with theranostic activities for diseases like cancer and bacterial infection using Surface Enhanced Raman Spectroscopy-based detection. Objective: The objective of the present article is to highlight the importance of popcorn-shaped nanoparticles for the treatment of various disease conditions like cancer, diabetes, ulcerative colitis, rheumatoid arthritis, etc. Methods: Nanopopcorns enter the target cells via conjugation with various proteins, aptamers, etc. to kill the diseased cell. Moreover, external magnetic radiations are provided to heat these metallic nanopopcorns for creating hotspots. All such activities can be tracked via SERS mechanism. Results: Nanopopcorns create alternative and minimally-invasive treatment strategies for inflammatory conditions and life-threatening diseases. Conclusion: In the near future, nanopopcorn-based drug delivery system can be an interesting field for research in medicinal nanotechnology.

Modeling of Reversible Solid Oxide Cell Stacks with an Open-Source Library

Fuel cells are potential contenders of the traditional internal combustion engines, with relative high efficiency and low/no emission of pollution and greenhouse gases. Electrolyzers convert electricity into chemical energy, e.g. hydrogen, and in case of high-temperature electrolyzers in syngas, e.g. hydrogen and carbon-monoxide, etc. A reversible solid oxide cell (rSOC) is able to operate in both modes. This represents a promising electrochemical device for future applications. Comprehensive experimental investigations on rSOCs are typically expensive and time-consuming. These may be conveniently augmented by numerical models to improve and optimize and enable the provision of more rapid prototypes. These models usually consider some or all of the underlying physical processes, e.g. heat and mass transfer (including thermal radiation), structural analysis, etc. They range from zero-dimensional (0-D) and 1-D models in system-level models1, 2 to coupled 3-D models in cell/stack-level applications.3–5 Stack/system level models are attracting more and more attention due to their practical applications to commercial/industrial designs. In this work, a steady-state, 3-D, non-isothermal, and homogenized stack model has been developed from an extension of previous studies4–6 and implemented into the open-source library, OpenFOAM.7 It addresses all major physical processes, including fluid flow, heat and mass transfer (including thermal radiation), and electrochemical reactions. The model strategy applies a multi-region approach to consider every unit-cell as different sub-regions, namely, cathode, anode, electrolyte, and interconnect. Inter region heat and mass transfer is prescribed during the calculations. The micro-structures within the subregions are treated using volume-averaging method, in which case, the flow distribution can be easily described by replacing the viscous losses with a drag or friction term in the governing momentum equation(s). This greatly decreases the computational effort,6 and predicts quite similar results to those from experimental measurements.5 In the present work a surface-to-surface (S2S) model, also referred to as a viewFactor model, is utilized to simulate the external thermal radiations. Internal radiation is neglected due to its relative unimportance.Figure 1: Comparisons of temperature variations between experimental measurements and simulations, i = 0.5 A cm−2 . The present model is applied to investigate the performance of an in-house designed rSOC stack, the key component of a 5/15kW-class rSOC system.8 A 1-D simulation is also performed with a previous developed Simulink model.1 The stack consists of four 10-layer sub-stacks with an active cell area per layer of 320 cm2. It operates in both fuel cell and electrolysis modes, in a temperature range of 600 – 800 ◦C. To reduce heat losses to adjacent components and ambient environment, it is surrounded by insulating plates. More details can be found in the recent publication.8 As shown by Figure 1, temperature variations are compared between experimental measurements and numerical predictions, at a mean current density of 0.5 A cm-2 . In fuel cell mode, the cell voltages are 0.818 V, 0.821 V, and 0.824 V, for the experiment, Simulink, and stack model, respectively. In the electrolysis mode, the values are 1.240 V, 1.234 V, and 1.260 V, respectively. These results indicate fairly good agreement between the predictions and experiments. It can be found that the stack model predicts smaller temperature deviations than is seen in the experiments and the Simulink predictions. However, the former consumes approximately 1 hour for every run, while the later costs only several minutes. In future work, thermal stresses, which play important roles in design optimization, will be considered. Considering the 3-D nature of the stress distribution, the coupling between present model and a structural analysis program/solver would be a promising topic.

Structural and optoelectronic properties change in Bi/In2Se3 heterostructure films by thermal annealing and laser irradiation

The amorphous materials are sensitive to external radiations and thermal annealing that brings changes in their structural and optical properties for optoelectronic applications. The present report shows the amorphous to crystalline structure transformation in Bi/In2Se3 by energy radiation and thermal annealing that modifies the linear as well as the nonlinear optical properties. The thermally evaporated Bi/In2Se3 film was subjected to 2.35 eV energy irradiation and 150 °C thermal annealing. The structural transition was probed by XRD, which revealed the formation of BiSe, Bi4Se3, and Bi2Se3 phases by replacing indium with an average crystallite size of ∼20 nm. The diffusion of Bi into In2Se3 host matrix modified the interfacial region as noticed from the field effect scanning electron microscopy pictures. The linear and nonlinear optical constants were evaluated from the UV–Visible data that show a significant change in the irradiated and annealed films due to the new phases. The change in direct and indirect bandgap is explained on the basis of density of defect states and degree of disorder. The significant change in the refractive index brings more freedom in designing multifunctional optoelectronic devices. The σopt and σelect changed noticeably with heat and energy treatment. The high value of χ3 (18.81 × 10−10 esu) for the Bi/In2Se3 film decreased significantly to 3.68 × 10−10 and 2.13 × 10−10 esu for the annealed and irradiated film. All the optical parameter changes due to annealing and irradiation are confined between the two-host materials In2Se3 and Bi/In2Se3. The corresponding changes were also observed in Raman spectroscopy data. The tuning of these linear and nonlinear parameters is useful for optoelectronics and photovoltaics.

Analysis of Incidence Risk for Different Types of Stroke among the Mayak Worker Cohort

The incidence risk estimates for different types of strokes among the cohort of 22 377 Mayak workers occupationally exposed to prolonged radiation and followed up until the end of 2013 are presented. Information about the work histories and estimates of the liver absorbed doses from external and internal radiations were obtained from the “Mayak Worker Dosimetry System—2013” database; medical data and lifestyle factors were obtained from the “Clinic” medical and dosimetry database. Over the entire follow-up period, 221 cases of intracerebral hemorrhage (ICH), 1463 cases of brain cerebral infarction (BI), and 342 cases of nonspecified stroke (NS) were registered in the study cohort. It was shown that the ICH, BI, and NS incidence risks in the study cohort were significantly associated with nonradiation factors such as gender, age, calendar period, duration of employment at the main plants, smoking, alcohol assumption, body mass index, and comorbidities (arterial hypertension and diabetes), which agreed with the literature data. Analyses did not reveal an effect of external γ-ray exposure on the ICH and BI incidence. However, NS relative risk (RR) was statistically significantly below the one in the groups of workers exposed to external γ-rays at the total absorbed liver doses above 0.20 Gy as compared with workers exposed at doses below 0.10 Gy. BI incidence RR was statistically significantly above the one in the groups of workers exposed to internal α-radiation at the total absorbed liver dose above 0.10 Gy as compared with workers exposed at lower doses. There was no effect of internal exposure on the ICH and NS incidence. These findings agreed with the results obtained earlier for the Mayak worker cohort.

DNA Dielectric and Electromagnetic Properties- Theoretical Background, Experimental Findings and Discussion

Intrinsic dielectric and electromagnetic properties of DNA, such as whether living cell DNA has electric properties and can interact with external electromagnetic radiations, or can source such radiations, or can function similar to an ordinary or fractal antenna, have been a matter of long-standing debate. We carried out a detailed study to assess these questions as well as the background of the possibility of intrinsic electromagnetism within DNA (both in situ and in vivo). In this objective report, building upon our previous studies and some recent experiments, we report our findings that no intrinsic or induced electromagnetism was observed in a variety of samples we studied using some of the high-precision and extremely sensitive instruments available to experimental biology studies. We argue the background of these findings that although DNA has dielectric properties and polarizability why no electromagnetism can exist within DNA and if any such properties existed, they would be impossible to be detected with currently available measurement methods. We conclude that DNA does not seem to act as fractal antenna, and that the only electromagnetic fields which can induce substantial morphological or functional changes within the DNA molecules are either high-intensity microwave fields which cause damage mainly by heating (so-called “RF cooking”) or ionizing radiation such as gamma rays which can cause single or double strand breaks in the DNA, both well-established facts after a large number of studies. No other electromagnetic activity of any kind was observed during our detailed tests, DNA appears similar to an ordinary polymer with no electric or magnetic activity intrinsic to it.

A Study of NaI(Tl) crystal encapsulation using organic scintillators for the dark matter search

Scintillating NaI(Tl) crystals are used for various rare decay experiments, such as dark matter searches. However, the hygroscopicity of NaI(Tl) crystals makes the construction of crystal detectors in these experiments challenging. Therefore, the crystal requires a tight encapsulation to prevent from air contact. More importantly, in a low radioactivity measurement, identification of external radiations and surface contamination is crucial to characterize the origin of total crystal radioactivities. Studies for the NaI(Tl) crystal encapsulation with active organic scintillator vetoes have been performed to mitigate the above-mentioned issues simultaneously. A bare crystal is directly coupled with liquid and plastic scintillators to tag external radiations that penetrate from the outer part of the crystal. We report the pulse shape discrimination between organic scintillator and the crystal scintillator in a single detector setup and their long-term stability.

On the Effects of Transfaulty Sensor Nodes in Stationary Wireless Sensor Network Systems

Due to less propagation delay and high bandwidth, radio frequency (RF) signal is generally used for communication between nodes in a wireless sensor network (WSN). These RF-based wireless sensor nodes suffer from communication impairment in the presence of external electromagnetic or nuclear radiation. Temporal presence of such external radiations leads to exhibit dynamic failure nature of sensor nodes in the WSN. When a sensor node cannot temporarily communicate with other nodes in the WSN in the presence of external radiation is termed as transfaulty node. These nodes typically resume their normal operation after the resumption of favorable (normal) conditions. The transfaulty sensor nodes may able to sense their surrounding correctly but cannot communicate with others temporarily . As a result, the transfaulty sensor nodes create dynamic communication holes, which create or remove and increase or decrease in their size during network operation. The temporal communication failure nature of transfaulty nodes impose detrimental effects on the network performance of the WSN. Therefore, this behavior is considered as temporary misbehavior of wireless sensor nodes. In this paper, we study the affects of transfaulty nodes on a stationary WSN. Simulation results show that the network performance degrades in the presence of transfaulty nodes in stationary WSNs. Hence, we also suggest some suitable remedies to restore the network performance of WSN in the presence of transfaulty nodes.

New Insights Into Soft-Faults Induced Cardiac Pacemakers Malfunctions Analyzed at System-Level via Model Checking

Progressive shrinking of CMOS device sizes has permitted reductions in power consumption and miniaturization of electronic devices. In parallel, modern pacemakers implemented with advanced technologies have proved to be more sensitive than earlier models to soft errors induced notably by external radiations. Traditionally, the analysis of the impact of soft faults (SFs), such as those induced by single-event upsets, on the behavior of pacemaker devices, has been carried out by dynamic radiation ground testing and clinical observations . However, these techniques are expensive. They can only be done very late in the design cycle, after the design is manufactured and in part after it is implanted. This paper presents a new model-based analysis of the impact of SFs on the behavior of cardiac pacemakers at a system level. It is performed by: 1) introducing a new probabilistic timed automata (PTA) model; 2) verifying this model against a set of functional properties to ensure it meets its specifications under normal conditions; 3) applying a new methodology to inject SFs at a certain time in the PTA model of the pacemaker and to verify their impact on the pacemaker’s behavior is introduced; and 4) identifying different scenarios for SFs that may lead to malfunction, including oversensing, undersensing , and output failure . The reported formal modeling is done in PRISM and the analysis is done with the Storm model checker.

Theory and applications of toroidal moments in electrodynamics: their emergence, characteristics, and technological relevance

AbstractDipole selection rules underpin much of our understanding in characterization of matter and its interaction with external radiation. However, there are several examples where these selection rules simply break down, for which a more sophisticated knowledge of matter becomes necessary. An example, which is increasingly becoming more fascinating, is macroscopic toroidization (density of toroidal dipoles), which is a direct consequence of retardation. In fact, dissimilar to the classical family of electric and magnetic multipoles, which are outcomes of the Taylor expansion of the electromagnetic potentials and sources, toroidal dipoles are obtained by the decomposition of the moment tensors. This review aims to discuss the fundamental and practical aspects of the toroidal multipolar moments in electrodynamics, from its emergence in the expansion set and the electromagnetic field associated with it, the unique characteristics of their interaction with external radiations and other moments, to the recent attempts to realize pronounced toroidal resonances in smart configurations of meta-molecules. Toroidal moments not only exhibit unique features in theory but also have promising technologically relevant applications, such as data storage, electromagnetic-induced transparency, unique magnetic responses and dichroism.

Experimental study on the thermal decomposition and combustion characteristics of nitrocellulose with different alcohol humectants

Although the thermal behaviors including thermal instability of nitrocellulose (NC) and its mixtures with some humectants have been comprehensively examined previously in the literature, their combustion characteristics have not been systematically studied. To address the issue, the combustion properties of NC with alcohol humectants are investigated by the means of the ISO 5660 cone calorimeter. Two kinds of NC-humectant mixtures with 30wt.% isopropanol and 30wt.% ethanol, respectively, were employed as samples. The tests were conducted under different external radiations, ranging from 0–15kW/m2. The experimental results indicate that the external radiation positively influences the peak heat release rate (HRR) intensity and the maximum mass loss rate (MLR), while the total heat release (THR) decreases with the elevated external radiation. Comparatively, the sample with isopropanol exhibits a higher fire risk, characterized by the higher peak HRR, THR and maximum MLR. Auxiliary investigating methods, including Scanning Electron Microscopy and Differential Scanning Calorimeter-Thermal Gravimetric Analysis, were applied to examine the micro structure and thermal behavior of NC-humectant mixtures. The results helped to explain the burning characteristics observed in the cone calorimeter tests.

Broad Spectrum UVA & UVB Photoprotectants: An Overview

Purpose : Due to the high exposure of our skin to sunlight which mainly comprises of ultraviolet radiation, a harmful effect is manifested on the skin and the integumentary system. Sunscreens are formulated which safeguards the epidermis of the skin from harmful UV radiations by reflecting, absorbing or by dispersion phenomena. This review focuses on the beneficial aspects of sunscreen and also presents a detail exposition about its formulation aspects and evaluation. Approach : The review introduces sunscreens and its traditional, chronological usage of sunscreen. The formulation and development of sunscreen emphasis on various UVA and UVB photo protectants used and its evaluation parameters is studied. Findings : Sunscreens are found to show the photo-protecting properties by absorption or by reflecting mechanism, which has a shielding effect towards the skin against harmful radiations. Conclusion : Sunscreens protects the skin absorbing or reflecting ultraviolet radiations. The application of sunscreens is an efficient method of protecting skin against UV radiations. Hence a sunscreen plays a vital role in protecting the skin from external harmful radiations.

External dose reconstruction for the former village of Metlino (Techa River, Russia) based on environmental surveys, luminescence measurements, and radiation transport modelling.

In the first years of its operation, the Mayak Production Association, a facility part of the Soviet nuclear weapons program in the Southern Urals, Russia, discharged large amounts of radioactively contaminated effluent into the nearby Techa River, thus exposing the people living at this river to external and internal radiations. The Techa River Cohort is a cohort intensely studied in epidemiology to investigate the correlation between low-dose radiation and health effects on humans. For the individuals in the cohort, the Techa River Dosimetry System describes the accumulated dose in human organs and tissues. In particular, organ doses from external exposure are derived from estimates of dose rate in air on the Techa River banks which were estimated from measurements and Monte Carlo modelling. Individual doses are calculated in accordance with historical records of individuals' residence histories, observational data of typical lifestyles for different age groups, and age-dependent conversion factors from air kerma to organ dose. The work here describes an experimentally independent assessment of the key input parameter of the dosimetry system, the integral air kerma, for the former village of Metlino, upper Techa River region. The aim of this work was thus to validate the Techa River Dosimetry System for the location of Metlino in an independent approach. Dose reconstruction based on dose measurements in bricks from a church tower and Monte Carlo calculations was used to model the historic air kerma accumulated in the time from 1949 to 1956 at the shoreline of the Techa River in Metlino. Main issues are caused by a change in the landscape after the evacuation of the village in 1956. Based on measurements and published information and data, two separate models for the historic pre-evacuation geometry and for the current geometry of Metlino were created. Using both models, a value for the air kerma was reconstructed, which agrees with that obtained in the Techa River Dosimetry System within a factor of two.