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Like any other facilities, nuclear facilities are likewise connected with risks to the personnel and environment. The impact assessment of any facility is one of the essential prerequisites for its smooth running. Uranium ore is processed through different stages, such as size reduction, leaching, filtration, product recovery and waste deposition. Different stages of the ore processing can redistribute the activity of radio-nuclides and their measurement is essential for the impact analysis of the facility. Variation in radon and gamma levels is internationally investigated as a marker for seasonality in the natural radiation environment of an area. Accordingly, investigation for both plant and solid waste disposal sites has been carried out for radon (²²²Rn) and gamma levels to examine the influence on the workers and environment. The radon concentration in the workplace is observed to vary between 20 and 150 Bq m⁻³, which is within the reference threshold of 300 Bq m⁻³ suggested in the ICRP recommendation (ICRP 2014). The impacts of the facility on the surrounding environment are indistinguishable from those of the background. Findings suggest that the seasonality of change in radon level is considerable at either site and the gamma level change in the mill is ascribed to the nature and quantity of the source rather than the seasonal influences.

The identification and monitoring of long-lived alpha-emitting radiotoxic radionuclide in nuclear waste management, environmental monitoring and internal dosimetry are crucial as far as the safety of individual, community and environment is concerned. This requires sample preparation techniques with thin, uniform and adherent deposition of actinides on the substrate for carrying accurate and high-resolution alpha-spectrometric measurements. Electrodeposition is one such technique. Standard sources prepared using this method can be used for calibration of detectors for alpha measurements. In this paper, we discuss the methodology adopted for electroplating Am-241 sources and subsequently carrying the standardization of electroplated sources with 2π-Proportional counter (PC). Efficiency of Am-241 electroplated source in 2πPC was determined to be 49%. The sources were further investigated for alpha-spectrometric measurements leading to the generation of high-resolution spectra exhibiting a full-width at half-maximum (FWHM) value of 38 keV. Scanning electron microscopy (SEM) for surface morphological studies yielded non-clustered deposition, indicating the even distribution of radionuclide and consequently, homogeneity. A tissue wipe test was performed to evaluate the adhesion of radionuclide on substrate. The present study reveals the absence of counts on wiped tissue indicating adherency in deposition.

Laboratories/facilities dealing with ionizing radiation encounter radiation field which are measured using suitable gamma radiation monitors, for area and personal monitoring. These radiation monitors are subjected to periodic calibrations to confirm that they are still fit for the purpose. In India, periodic calibration of these radiation monitors is carried out by NABL accredited calibration laboratories using source exposure devices containing radionuclide sources of ¹³⁷Cs and/or ⁶⁰Co. Calibration laboratories get the output from these source exposure devices standardized by RSSD, BARC, Mumbai. RSSD, BARC, provides a report on the measured output, in the form of air kerma rates at different distances, which is traceable to relevant national standards. The laboratory then uses the standardized radiation field in day-to-day calibration, by taking air kerma rate mostly at distance of 100 cm (fixed distance) as reference for estimating radiation fields at other distances by using inverse square law. The air kerma rate values obtained by the using inverse square law shows deviation from the measured values with an allowed deviation up to 5%. The impact of this deviation cannot be corrected thus is accounted in the form of uncertainty. This paper presents an average air kerma strength-based methodology which provides a simple and effective mechanism for estimating the conventional true value of air kerma rate at various distance which adds lower uncertainty to overall uncertainty, as compared to the method of using a fixed or reference distance (say 100 cm) based air kerma rate.

Surface electromyography is an important and widely used biomedical measurement technique. In biomedical engineering, obtaining high-quality EMG data and processing it in real-time is challenging. Their calibration repeatability and reliability, on the other hand, remain in discussion. Furthermore, the metrological elements of EMG systems have not yet been studied. In this research work, a portable EMG acquisition module has been developed, and the uncertainty of two EMG characteristics for four everyday hand motions has been investigated. Furthermore, an inter-instrument comparison has been carried out in a controlled environment. For multiple trials, the result has been estimated for 10 people. While designing the experiment, two major uncertainty factors, muscle selection/electrode placement and subjective analysis, have been taken into consideration. The developed system's inter-instrument performance has been found to be similar to that of the existing system (p-value > 0.05). The total uncertainty of the developed system has been found to be in the range of 0.0106–0.0196% (p-value > 0.05) for RMS and 0.1001–0.2084% (p-value > 0.05) for MF. The existing commercial system, in contrast, exhibited uncertainty in the range of 0.0171–0.0359% (p-value > 0.05) for RMS and 0.1010–0.2088% (p-value > 0.05) for MF. The developed EMG acquisition system's performance and cost-effectiveness validate its utility and acceptability for low-cost product development.

An acoustic comparison coupler has been designed by the acoustic and vibration research group, National Research and Innovation Agency (BRIN). This research prototype is developed to be utilized by a private and industrial laboratory to comply with periodic tests of a sound level meter (SLM) for frequency weighting as the primary parameter. Further, the performance has been demonstrated in the previous paper. Nevertheless, the comparison test among the acoustic calibration systems associated with this mandatory parameter test has not been conducted yet. Therefore, the purpose of this work is to conduct the validation of this prototype as the SLM calibration system using the two established methods consists of the free field method by using free field facilities and insert voltage technique, and the second method by utilizing the multifunction acoustic calibrator in a pressure field condition. The measurement procedure is carried out following the standard IEC 61672–3. Therefore, the results are compared to the acceptance limit stated by this standard. This work also quantifies the uncertainty measurements that are provided by these methods. From the results, the measured frequency weighting is obtained using these methods. The deviation to the reference values and the expanded uncertainty measurement are also reported.

This manuscript proposed a compact four-port multiple input multiple output (MIMO) antenna based on four split-ring resonators (SRR) at the top and a defected ground structure (DGS) at the bottom of the substrate for 5G communication. SRRs are used to resonate at 4 GHz frequency in mid-5G band. A slot of “ + ” symbol is cut at the bottom (DGS) to enlarge the bandwidth. The proposed antenna also achieved a high-5G frequency band (26.8–29.8 GHz) (n257/n258 band) by four square-shaped ring slots at the ground plane. It further enhances the bandwidth in mid-5G band (2.9–6 GHz) (n74/n75/n76/n77/n78 band) and helps to achieve a high degree of isolation between each radiating element (over 40 dB) at both the 5G bands. The size of the proposed MIMO antenna is 60 mm × 60 mm × 1.6 mm. It achieves a maximum gain of 4.59 dB, 4.32 dB at the mid-5G and high-5G band, respectively. The maximum radiation efficiencies achieved are 89%, 81% at the mid-5G and high-5G band, respectively. The diversity functionality of the antenna is also outstanding as the value of ECC is 0.01–0.42, DG is 9.6–10 dB, and TARC is less than − 10 dB measured in both the bands. The entire performance of the proposed antenna is practically verified, discussed and presented.

In the present study, trends and variations in carbon dioxide (CO₂), temperature and water vapour are analysed using 9 years (2003–2011) of mid-tropospheric (300–500 hPa) Atmospheric Infrared Sounder (AIRS) data. The focus of analysis remains on both a global as well as regional (India) scale along with improved understanding of their inter relationship. It was observed that the mid-tropospheric carbon dioxide increased from ~ 373 to ~ 393 ppm and ~ 373 to ~ 392 ppm, respectively, over the globe and the Indian region during 9 years. However, no substantial trends (increasing or decreasing) were observed in the temperature and water vapour observations for the same period of time. De-trended data of CO₂, temperature and water vapour were further analysed to understand the inter relationship between these parameters and the influence of two greenhouse gases (CO₂ and water vapour) on temperature. Analysis suggests a very high correlation (~ 0.90) between temperature and water vapour, however, no significant correlation was observed between temperature and carbon dioxide data, indicating that change in water vapour may have stronger influence on temperature compared to the change in CO₂, this feature can play a more significant role as a greenhouse gas than CO₂.

This paper provides information on the performance study of precision current shunts in the context of their output voltage stability. Besides, it briefly focuses on the phenomena affecting the steady state of these measuring instruments. The authors present a methodology for testing current shunts to ensure a high-quality result of current measurement. The investigation highlights three characteristics of shunts (the dependence of resistance on temperature, the response of the output voltage to a fast increase of current, and the transition from a cold state to a warm one). The test equipment with precision shunts were considered during the experimental examination. The results of an investigation confirmed satisfactory operational properties and compliance with the needs of laboratories. Additionally, the authors emphasize using a precision shunt as a measuring standard when calibrating other instruments like high-precision digital ammeters. From this point of view, the simplified mathematical modeling of the change in the AC-DC transfer difference, depending on the resistance change caused by the warming current, was carried out.

Measurement of PM_2.5 is carried out simultaneously outdoors as well as indoors using a Compact and Useful PM_2.5 Instrument (CUPI) from Nov 2018 to Oct 2019. A high-time resolution data (~ 2 min interval) was recorded at Dwarka (West Delhi), New Delhi, to investigate the difference between outdoor and indoor ambient particulate matter. Year-long observations provide an opportunity to decipher that indoor PM_2.5 concentration increases significantly from mid-November 2018 to mid-December 2018. During this high concentration occurrence of PM_2.5, outdoor concentration was higher in the range of 100–200 µg/m³ than indoor. Indoor pollution was less by 30–50% in comparison to the outdoor environment. Analyses reveal that during a high pollution period, intermittently for a short period, outdoor PM_2.5 was less, which coincides with clear weather days suggesting that indoor pollution did not disperse due to a closed environment. Diurnal variation of PM_2.5 clearly shows high concentration stays until 12:00 noon in both indoor and outdoor environments, which reduces in the afternoon and again picks up in the evening. Diurnal variation of solar radiation showed a consistent increase from 9 am to 2 pm, while relative humidity declined considerably from 10 am to 4 pm (local time); these two factors correspond to less concentration in both indoor and outdoor environments. However, there is no significant difference between outdoor and indoor concentration during summer and monsoon season.

The production of reference materials necessitates, among other factors, evaluations of homogeneity and stability. The aim of the homogeneity study is to ensure uniformity in property values across all samples. On the other hand, stability pertains to a sample’s ability to retain its property value over time. ISO Guide 35 dictates that homogeneity, between and within samples, is appraised using a one-way random effects analysis of variance, while stability is gauged by a univariate linear regression model. Both these statistical techniques presuppose the normality and homoscedasticity of the residuals. Notably, the ISO Guide 35 standard omits any reference to the assumption of homoscedasticity in its prescribed statistical methods. This communication introduces the Shapiro–Wilk and Koenker–Bassett tests as tools to verify the assumptions of normality and homoscedasticity, respectively. Moreover, it advances the feasible generalized least squares method as a remedy for instances where these assumptions are breached. Initial findings suggest that, in certain scenarios, breaches in statistical model assumptions might influence evaluations of homogeneity and/or stability.