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Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) cause significant environmental concerns. Atmospheric PCDD/Fs permeate water bodies and other ecosystems through wet and dry deposition. In an urban site, dry deposition flux samples of gaseous phase PCDD/Fs were collected by a water surface sampler (WSS) operated between June 2022 and June 2023. There is a conspicuous absence of literature on the direct measurement of dry deposition flux levels in the gaseous phase of PCDD/Fs. In the study, PCDD/Fs in the gas phase reaching the WSS dissolved in the water according to Henry's Law. The PCDD/Fs in the water were transferred to an XAD-2 resin column, sorbing the dissolved PCDD/Fs. The average monthly gas phase dry deposition flux was 34.07 ± 9.35 pg/m2-day (7.35 ± 2.16 pg I-TEQ/m2-day). The highest flux was measured in March (49.53 pg/m2-day), and the lowest was in August (18.64 pg/m2-day). These values indicated the direct flux from air to water. The atmospheric concentration of the gas-phase ranged from 68.38 to 126.88 fg/m3 (13.22-25.01 fg I-TEQ/m3). Dry deposition fluxes and concentrations of atmospheric PCDD/Fs were bigger in the colder months than in the warmer months. This was probably due to a significant increase in residential heating during the colder months, decreased photochemical reactions, and lower mixing heights. Regarding congeners in the dry deposition flux and concentration values in I-TEQ units, 2,3,7,8-TCDD compound predominated with the proportions of 31.61 ± 7.76% and 29.09 ± 12.34%, respectively. Concurrently measured dry deposition flux (Fg) and ambient air concentration (Cg) of PCDD/Fs were considered in the determination of mass transfer coefficient (MTC = Fg/Cg) calculation for each PCDD/F congener. The average MTC for targeted 17 PCDD/Fs was 0.45 ± 0.15 cm/s, and it fluctuated between 0.89 ± 0.30 cm/s for 2,3,7,8-TCDF and 0.2 ± 0.16 cm/s for OCDD.

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Solid waste landfills are responsible for much of the anthropogenic methane emitted from the waste sector. The quantification of fugitive CH4 emissions from a landfill is to date characterised by high uncertainty and several methodologies have been devised to estimate emission fluxes. Unmanned Aerial Vehicles (UAVs, also known as drones) are revolutionising the way CH4 emission monitoring is conceived and offer new opportunities for quantifying emission fluxes from a landfill, mainly due to recent advances in sensor miniaturisation that make these instruments lighter and more suitable to be equipped on a drone. The paper analyses publications from the period 2014-2024 that illustrate UAV-based methods that can be used for this purpose, identifying experiences in the field and the current state of research. The review has highlighted a current research status characterised by a strong experimental focus, with few tests carried out in landfills under real emission conditions (33 % of the reviewed papers). Since 2018, there has been a growing interest in open-path sensors, tested in some controlled-release experiments according to different configurations which have given promising results, but experiences are limited and there are no experiments conducted directly in landfills. In general, the UAV-based methods identified by this systematic review are characterised by unclear uncertainties. Drones are a viable alternative to traditional monitoring methods at landfills and allow data to be acquired with a spatial and temporal resolution that can hardly be achieved by other low-cost methods. However, further studies and field trials are needed to better understand methodological aspects: especially the uncertainty of each step in the quantification process need to be properly analysed and quantified more precisely.

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Condensed tannins are common in vegetative tissues of woody plants, including in roots. In hybrid poplar (Populus tremula x alba; also known as P. x canescens) CT assays indicated they were most concentrated in younger white roots and at the root tip. Furthermore, CT-specific staining of embedded tissue sections demonstrated accumulation in root cap cells and adjacent epidermal cells, as well as a more sporadic presence in cortex cells. In older, brown roots as well as roots with secondary growth (cork zone), CT concentration was significantly lower. The insoluble fraction of CTs was greatest in the cork zone. To determine if CT accumulation correlates with nutrient uptake in poplar roots, a microelectrode ion flux measurement (MIFE™) system was used to measure flux along the root axis. Greatest NH4 + uptake was measured near the root tip, but NO3- and Ca2+ did not vary along the root length. In agreement with earlier work, providing poplars with ample nitrogen led to higher accumulation of CTs across root zones. To test the functional importance of CTs in roots directly, CT-modified transgenic plants could be important tools.

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This paper comprehensively reviews sensors and sensing devices developed or/and proposed so far utilizing two smart materials: electrorheological fluids (ERFs) and magnetorheological materials (MRMs) whose rheological characteristics such as stiffness and damping can be controlled by external stimuli; an electrical voltage for ERFs and a magnetic field for MRMs, respectively. In this review article, the MRMs are classified into magnetorheological fluids (MRF), magnetorheological elastomers (MRE) and magnetorheological plastomers (MRP). To easily understand the history of sensing research using these two smart materials, the order of this review article is organized in a chronological manner of ERF sensors, MRF sensors, MRE sensors and MRP sensors. Among many sensors fabricated from each smart material, one or two sensors or sensing devices are adopted to discuss the sensing configuration, working principle and specifications such as accuracy and sensitivity. Some sensors adopted in this article include force sensors, tactile devices, strain sensors, wearable bending sensors, magnetometers, display devices and flux measurement sensors. After briefly describing what has been reviewed in a conclusion, several challenging future works, which should be undertaken for the practical applications of sensors or/and sensing devices, are discussed in terms of response time and new technologies integrating with artificial intelligence neural networks in which several parameters affecting the sensor signals can be precisely and optimally tuned. It is sure that this review article is very helpful to potential readers who are interested in creative sensors using not only the proposed smart materials but also different types of smart materials such as shape memory alloys and active polymers.

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Superhydrophobicity-enabled jumping-droplet condensation and frosting have great potential in various engineering applications, ranging from heat transfer processes to antifog/frost techniques. However, monitoring such droplets is challenging due to the high frequency of droplet behaviors, cross-scale distribution of droplet sizes, and diversity of surface morphologies. Leveraging deep learning, we develop a semisupervised framework that monitors the optical observable process of condensation and frosting. This system is adept at identifying transient droplet distributions and dynamic activities, such as droplet coalescence, jumping, and frosting, on a variety of superhydrophobic surfaces. Utilizing this transient and dynamic information, various physical properties, such as heat flux, jumping characteristics, and frosting rate, can be further quantified, conveying the heat transfer and antifrost performances of each surface perceptually and comprehensively. Furthermore, this framework relies on only a small amount of annotated data and can efficiently adapt to new condensation conditions with varying surface morphologies and illumination techniques. This adaptability is beneficial for optimizing surface designs to enhance condensation heat transfer and antifrosting performance.

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Heat flux measurement shows potential for the early detection of infectious growth. Our research is motivated by the possibility of using heat flux sensors for the early detection of infection on aortic vascular grafts by measuring the onset of bacterial growth. Applying heat flux measurement as an infectious marker on implant surfaces is yet to be experimentally explored. We have previously shown the measurement of the exponential growth curve of a bacterial population in a thermally stabilized laboratory environment. In this work, we further explore the limits of the microcalorimetric measurements via heat flux sensors in a microfluidic chip in a thermally fluctuating environment.

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Fluorescently labelled compounds are often employed to study the paracellular properties of epithelia. For flux measurements, these compounds are added to the donor compartment and samples collected from the acceptor compartment at regular intervals. However, this method fails to detect rapid changes in permeability. For continuous transepithelial flux measurements in an Ussing chamber setting, a device was developed, consisting of a flow-through chamber with an attached LED, optical filter, and photodiode, all encased in a light-impermeable container. The photodiode output was amplified and recorded. Calibration with defined fluorescein concentration (range of 1 nM to 150 nM) resulted in a linear output. As proof of principle, flux measurements were performed on various cell lines. The results confirmed a linear dependence of the flux on the fluorescein concentration in the donor compartment. Flux depended on paracellular barrier function (expression of specific tight junction proteins, and EGTA application to induce barrier loss), whereas activation of transcellular chloride secretion had no effect on fluorescein flux. Manipulation of the lateral space by osmotic changes in the perfusion solution also affected transepithelial fluorescein flux. In summary, this device allows a continuous recording of transepithelial flux of fluorescent compounds in parallel with the electrical parameters recorded by the Ussing chamber.

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The knowledge of the space radiation environment in spacecraft transition and in Mars vicinity is of importance for the preparation of the human exploration of Mars. ExoMars Trace Gas Orbiter (TGO) was launched on March 14, 2016 and was inserted into circular Mars science orbit (MSO) with a 400 km altitude in March 2018. The Liulin-MO dosimeter is a module of the Fine Resolution Epithermal Neutron Detector (FREND) aboard ExoMars TGO and has been measuring the radiation environment during the TGO interplanetary travel to Mars and continues to do so in the TGO MSO. One of the scientific objectives of the Liulin-MO investigations is to provide data for verification and benchmarking of the Mars radiation environment models. In this work we present results of comparisons of the flux measured by the Liulin-MO in TGO Mars orbit with calculated estimations. Described is the methodology for estimation the particle flux in Liulin-MO detectors in MSO, which includes modeling the albedo spectra and procedure for calculation the fluxes, recorded by Liulin-MO on the basis of the detectors shielding model. The galactic cosmic rays (GCR) and Mars albedo radiation contribution to the detectors count rate was taken into account. The GCR particle flux was calculated using the Badhwar O'Neil 2014 model for December 1, 2018. Detailed calculations of the albedo spectra of protons, helium ions, neutrons and gamma rays at 70 km height, performed with Atmospheric Radiation Interaction Simulator (AtRIS), were used for deriving the albedo radiation fluxes at the TGO altitude. In particular, the sensitivity of the Liulin-MO semiconductor detectors to neutron and gamma radiation has been considered in order to calculate the contribution of the neutral particles to the detected flux. The results from the calculations suggest that the contribution of albedo radiation can be about 5% of the measured total flux from GCR and albedo at the TGO altitude. The critical effect of TGO orientation, causing different shading of the GCR flux by Mars, is also analysed in detail. The comparison between the measurements and estimations shows that the measured fluxes exceed the calculated values by at least 20% and that the effect of TGO orientation change is approximately the same for the calculated and measured fluxes. Accounting for the ACR contribution, secondary radiation and the gradient of GCR spectrum from 1 AU to 1.5 AU, the calculated flux may increase to match the measurement results. The results can serve for the benchmarking of GCRs models at Martian orbit.

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Ecologically fragile areas account for more than 60% of land area in China. Global change and human activities are aggravating ecosystem degradation and reducing the carrying capacity of resources and environment. It is important to accurately quantify the carrying capacity of resources and environment in ecologically fragile areas to deal with the risk and challenge of global change and to speed up the construction of ecological civilization. How-ever, existing methods evaluating carrying capacity of resources and environment are difficult to reflect the transmission effect of ecosystem structures, processes and functions changes among resource, environment and carrying capacity. Therefore, it is essential to establish a field observation network and obtain the comprehensive data set of resource and environment elements-ecosystem structure, function and process-ecosystem carrying capacity for develo-ping the theory and evaluation method. We introduced the collaborative monitoring networks of flux and UAV photographing, including the thoughts, practice, and preliminary results in the study of ecosystem structure, process and function in the fragile ecosystems of China. Based on the achievements and progress, we proposed the application of collaborative monitoring networks in capacity evaluation.

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This study investigates temporal variability on landfill methane (CH4) emissions from an old abandoned Danish landfill, caused by the rate of changes in barometric pressure. Two different emission quantification techniques, namely the dynamic tracer dispersion method (TDM) and the eddy covariance method (EC), were applied simultaneously and their results compared. The results showed a large spatial and temporal CH4 emission variation ranging from 0 to 100 kg h-1 and 0 to 12 µmol m-2 s-1, respectively. Landfill CH4 emissions dynamics were influenced by two environmental factors: the rate of change in barometric pressure (a strong negative correlation) and wind speed (a weak positive correlation). The relationship between CH4 emissions and the rate of change in barometric pressure was more complicated than a linear one, thereby making it difficult to estimate accurately annual CH4 emissions from a landfill based on discrete measurements. Furthermore, the results did not show any clear relationship between CH4 emissions and ambient temperature. Large seasonal variations were identified by the two methods, whereas no diurnal variability was observed throughout the investigated period. CH4 fluxes measured with the EC method were strongly correlated with emissions from the TDM method, even though no direct relationship could be established, due to the different sampling ranges of the two methods and the spatial heterogeneity of CH4 emissions.

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Pulpal blood supply can be measured noninvasively and objectively via laser-Doppler fluxmetry. The aim of the study was to measure and compare pulpal laser-Doppler (LD) flux values for permanent non-carious teeth and carious teeth with different degrees of caries progression. Conventional sensitivity tests were also conducted for a comparative analysis to clarify the difference between tooth sensitivity and vitality. Carious lesions were detected and assessed in 15 adult subjects using the International Caries Detection and Assessment System (ICDAS) criteria. Pulpal sensitivity of selected carious teeth (without previous prosthetic restoration or endodontic treatment) and suitable caries-free teeth were then tested with a cold stimulus and subsequently with a weak electric current, whereas their pulpal LD flux was recorded at a separate visit using individually designed silicone probe holders. The LD flux values for teeth with an ICDAS score 6 were significantly lower compared to the values for teeth with an ICDAS score 1 (p < 0.05). Pulpal LD flux values of teeth with active caries were significantly lower than those of teeth with solely inactive carious lesions (p < 0.05). The degree of agreement between sensitivity and vitality testing was fair within both of the pairs: cold test/LDF (κk = 0.232, p = 0.00) and electric test/LDF (κk = 0.354, p = 0.00). Pulpal LD flux measurement proved to be reliable in the pulp vitality assessment of carious and non-carious teeth and might improve the reliability of clinical decisions when used in addition to standard clinical diagnostic protocols.

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We report the development of a laser gas analyzer that measures gas concentrations at a data rate of 100 Hz. This fast data rate helps eddy covariance calculations for gas fluxes in turbulent high wind speed environments. The laser gas analyzer is based on derivative laser absorption spectroscopy and set for measurements of water vapor (H2O, at wavelength ~1392 nm) and carbon dioxide (CO2, at ~2004 nm). This instrument, in combination with an ultrasonic anemometer, has been tested experimentally in both marine and terrestrial environments. First, we compared the accuracy of results between the laser gas analyzer and a high-quality commercial instrument with a max data rate of 20 Hz. We then analyzed and compared the correlation of H2O flux results at data rates of 100 Hz and 20 Hz in both high and low wind speeds to verify the contribution of high frequency components. The measurement results show that the contribution of 100 Hz data rate to flux calculations is about 11% compared to that measured with 20 Hz data rate, in an environment with wind speed of ~10 m/s. Therefore, it shows that the laser gas analyzer with high detection frequency is more suitable for measurements in high wind speed environments.

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Understanding of cadmium (Cd) uptake mechanism and development of lower Cd crop genotypes are crucial for combating its phytotoxicity and meeting 70% increase in food demand by 2050. Bio-accumulation of Cd continuously challenges quality of life specifically in regions without adequate environmental planning. Here, we investigated the mechanisms operating in Cd tolerance of two rice genotypes (Heizhan-43 and Yinni-801). Damage to chlorophyll contents and PSII, histochemical staining and quantification of reactive oxygen species (ROS), cell viability and osmolyte accumulation were studied to decipher the interactions between Cd and zinc (Zn) by applying two Cd and two Zn levels (alone as well as combined). Cd2+ and Ca2+ fluxes were also measured by employing sole Cd100 (100 µmol L-1) and Zn50 (50 µmol L-1), and their combination with microelectrode ion flux estimation (MIFE) technique. Cd toxicity substantially reduced chlorophyll contents and maximal photochemical efficiency (Fv/Fm) compared to control plants. Zn supplementation reverted the Cd-induced toxicity by augmenting osmoprotectants and interfering with ROS homeostasis under combined treatments, particularly in Yinni-801 genotype. Fluorescence microscopy indicated a unique pattern of live and dead root cells, depicting more damage with Cd10, Cd15 and Cd15+Zn50. Our results confer that Cd2+ impairs the uptake of Ca2+ whereas, Zn not only competes with Cd2+ but also Ca2+, thereby modifying ion homeostasis in rice plants. This study suggests that exogenous application of Zn is beneficial for rice plants in ameliorating Cd toxicity in a genotype and dose dependent manner by minimizing ROS generation and suppressing collective oxidative damage. The observations confer that Yinni-801 performed better than Heizhan-43 genotype mainly under combined Zn treatments with low-Cd, presenting Zn fortification as a solution to increase rice production.

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Estimation of regional soil carbon flux is very important for the study of the global carbon cycle. The spatial heterogeneity of soil respiration prevents the actual status of regional soil carbon flux from being revealed by measurements of only one or a few spatial sampling positions, which are usually used by traditional studies for the limitation of measurement instruments, so measuring in many spatial positions is very necessary. However, the existing instruments are expensive and cannot communicate with each other, which prevents them from meeting the requirement of synchronous measurements in multiple positions. Therefore, we designed and implemented an instrument for soil carbon flux measuring based on dynamic chamber method, SCFSen, which can measure soil carbon flux and communicate with each other to construct a sensor network. In its working stage, a SCFSen node measures the concentration of carbon in the chamber with an infrared carbon dioxide sensor for certain times periodically, and then the changing rate of the measurements is calculated, which can be converted to the corresponding value of soil carbon flux in the position during the short period. A wireless sensor network system using SCFSens as soil carbon flux sensing nodes can carry out multi-position measurements synchronously, so as to obtain the spatial heterogeneity of soil respiration. Furthermore, the sustainability of such a wireless sensor network system makes the temporal variability of regional soil carbon flux can also be obtained. So SCFSen makes thorough monitoring and accurate estimation of regional soil carbon flux become more feasible.

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This study described a pH-gradient dissolution method combined with flux measurements as an in vitro tool for assessing the risk of bioavailability reduction due to drug-drug interactions (DDI) caused by acid reducing agents (ARAs). The device incorporates absorption chambers into USP II dissolution vessels, with fiber optic UV-probes monitoring concentration in situ. Dosage forms of Genentech BCS class II drugs, GDC-0810, GDC-0941, and compound A, were tested by starting the dissolution in either pH 1.6 or pH 4.0 media then converting to FaSSIF after 30 min. GDC-0810 showed no significant difference in flux between the two conversion experiments. A supersaturation phase was observed for GDC-0941 in the pH 1.6 experiments after media conversion to FaSSIF; however, it did not appear to occur in the pH 4.0 experiment due to low drug solubility at pH 4.0, resulting in a 95% decrease in flux compared to pH 1.6 experiment. The extent of flux reduction and the total accumulated API mass in the absorption chamber agreed well with the 89% reduction in mean Cmax and the 82% reduction in mean AUC from dog PK study between animals treated with pentagastrin and famotidine. Testing of the compound A optimized formulation tablets showed a 25% reduction in flux and in vitro absorbed amount by changing pH 1.6 to 4.0, correlating well with the AUC decrease in clinical studies. Good correlation between in vitro data and in vivo PK data demonstrated the applicability of the method for formulators to develop drug products mitigating DDI from ARAs.

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In this work, we introduce a screening method for the evaluation of the natural attenuation rates in the subsurface at sites contaminated by petroleum hydrocarbons. The method is based on the combination of the data obtained from standard source characterization with dynamic flux chambers measurements. The natural attenuation rates are calculated as difference between the flux of contaminants estimated with a non-reactive diffusive model starting from the concentrations of the contaminants detected in the source (soil and/or groundwater) and the effective emission rate of the contaminants measured using dynamic flux chambers installed at ground level. The reliability of this approach was tested in a contaminated site characterized by the presence of BTEX in soil and groundwater. Namely, the BTEX emission rates from the subsurface were measured in 4 seasonal campaigns using dynamic flux chambers installed in 14 sampling points. The comparison of measured fluxes with those predicted using a non-reactive diffusive model, starting from the source concentrations, showed that, in line with other recent studies, the modelling approach can overestimate the expected outdoor concentration of petroleum hydrocarbons even up to 4 orders of magnitude. On the other hand, by coupling the measured data with the fluxes estimated with the diffusive non-reactive model, it was possible to perform a mass balance to evaluate the natural attenuation loss rates of petroleum hydrocarbons during the migration from the source to ground level. Based on this comparison, the estimated BTEX loss rates in the test site were up to almost 0.5kg/year/m2. These rates are in line with the values reported in the recent literature for natural source zone depletion. In short, the method presented in this work can represent an easy-to-use and cost-effective option that can provide a further line of evidence of natural attenuation rates expected at contaminated sites.

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Global climate change is expected to increase drought duration and intensity in certain regions while increasing rainfall in others. The quantitative consequences of increased drought for ecosystems are not easy to predict. Process-based models must be informed by experiments to determine the resilience of plants and ecosystems from different climates. Here, we demonstrate what and how experimentally derived quantitative information can improve the representation of stomatal and non-stomatal photosynthetic responses to drought in large-scale vegetation models. In particular, we review literature on the answers to four key questions: (1) Which photosynthetic processes are affected under short-term drought? (2) How do the stomatal and non-stomatal responses to short-term drought vary among species originating from different hydro-climates? (3) Do plants acclimate to prolonged water stress, and do mesic and xeric species differ in their degree of acclimation? (4) Does inclusion of experimentally based plant functional type specific stomatal and non-stomatal response functions to drought help Land Surface Models to reproduce key features of ecosystem responses to drought? We highlighted the need for evaluating model representations of the fundamental eco-physiological processes under drought. Taking differential drought sensitivity of different vegetation into account is necessary for Land Surface Models to accurately model drought responses, or the drought impacts on vegetation in drier environments may be over-estimated.

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This paper presents an extension of our previous wind-tunnel study (Nosek et al., 2016) in which we highlighted the need for investigation of the removal mechanisms of traffic pollution from all openings of a 3D street canyon. The extension represents the pollution flux (turbulent and advective) measurements at the lateral openings of three different 3D street canyons for the winds perpendicular and oblique to the along-canyon axis. The pollution was simulated by emitting a passive gas (ethane) from a homogeneous ground-level line source positioned along the centreline of the investigated street canyons. The street canyons were formed by courtyard-type buildings of two different regular urban-array models. The first model has a uniform building roof height, while the second model has a non-uniform roof height along each building's wall. The mean flow and concentration fields at the canyons' lateral openings confirm the findings of other studies that the buildings' roof-height variability at the intersections plays an important role in the dispersion of the traffic pollutants within the canyons. For the perpendicular wind, the non-uniform roof-height canyon appreciably removes or entrains the pollutant through its lateral openings, contrary to the uniform canyon, where the pollutant was removed primarily through the top. The analysis of the turbulent mass transport revealed that the coherent flow structures of the lateral momentum transport correlate with the ventilation processes at the lateral openings of all studied canyons. These flow structures coincide at the same areas and hence simultaneously transport the pollutant in opposite directions.

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The Indian Institute of Technology Kanpur (IIT Kanpur) possesses a PuBe neutron source facility with an initial activity of 5 Ci, dated September 1966 (nearly 50 years ago). An understanding of the present activity and the rate of its change will allow implementation of proper radiological safety procedures and future radiological safety planning. Knowing the absolute neutron flux will help us in future neutron activation studies. These details are also important to ensure proper security precautions. In our work, we attempt to identify the isotopic composition to determine the rate of change of the source and the absolute thermal neutron flux of plutonium beryllium (PuBe) sample at IIT Kanpur. We have used gamma-ray spectroscopy for determining the isotopic composition of the PuBe neutron source. After utilizing gamma-ray spectroscopy it is found that the source is composed of 239Pu and a small amount of 241Am is present as an impurity. The mass ratio of 241Am to 239Pu is found to be approximately 18.1µg/g with an uncertainty of 1.39%. Delayed gamma neutron activation analysis (DGNAA) is used to determine the thermal neutron flux of the same PuBe neutron source using copper, cobalt, nickel and cadmium samples. The average thermal neutron flux as calculated from DGNAA is approximately 1.27×103n/(cm2-s) at 1cm above the PuBe neutron source.

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Recommended best practices in monitoring of product status during pharmaceutical freeze drying are presented, focusing on methods that apply to both laboratory and production scale. With respect to product temperature measurement, sources of uncertainty associated with any type of measurement probe are discussed, as well as important differences between the two most common types of temperature-measuring instruments-thermocouples and resistance temperature detectors (RTD). Two types of pressure transducers are discussed-thermal conductivity-type gauges and capacitance manometers, with the Pirani gauge being the thermal conductivity-type gauge of choice. It is recommended that both types of pressure gauge be used on both the product chamber and the condenser for freeze dryers with an external condenser, and the reasoning for this recommendation is discussed. Developing technology for process monitoring worthy of further investigation is also briefly reviewed, including wireless product temperature monitoring, tunable diode laser absorption spectroscopy at manufacturing scale, heat flux measurement, and mass spectrometry as process monitoring tools.

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