Radiometric Parameters Research Articles

Surgical treatment of mobile planovalgus deformation of feet using calcaneal osteotomy based on preoperative computer modeling in adolescent: a retrospective cohort study

Background: Evans calcaneal osteotomy is one of the recognized surgical techniques for the treatment of flat-valgus foot deformity in children over 12 years of age, which allows simultaneous multiplanar correction. Preoperative planning of the formed diastasis parameters to reduce the number of cases of hypo- and hypercorrection remains an urgent issue. AIM: To evaluate the results of Evans calcaneal osteotomy using the developed method of preoperative planning and fixation with the individual H-shaped reconstructive plate. MATERIALS AND METHODS: This study included 64 children aged 12–17 years with symptomatic planovalgus deformity, who were divided into two groups: in the main group, preoperative planning was used according to the developed method; in the control group for intraoperative control of correction was used only fluoroscopy and visual assessment. To study the effectiveness of the developed method, we used dynamic assessment of radiometric parameters and AOFAS questionnaire results before and after surgery. We also took into account the changes in the Foot Posture Index 6 and the Chippaux-Smirak and Stasheli podometric indices. RESULTS: In comparison with the control group, the main group showed a reduction in the swelling period after surgery, as well as the timing of the onset of full limb support, and a significant decrease in the incomplete correction. Similar dynamics was observed when studying the groups according to the Foot Posture Index 6 scale and podometric indices. CONCLUSION: The use of the developed method of preoperative planning during the Evans operation has shown its effectiveness for the treatment of flexible flatfoot deformity of the feet in adolescence.

An Advanced Quality Assessment and Monitoring of ESA Sentinel-1 SAR Products via the CyCLOPS Infrastructure in the Southeastern Mediterranean Region

The Cyprus Continuously Operating Natural Hazards Monitoring and Prevention System, abbreviated CyCLOPS, is a national strategic research infrastructure devoted to systematically studying geohazards in Cyprus and the Eastern Mediterranean, Middle East, and North Africa (EMMENA) region. Amongst others, CyCLOPS comprises six permanent sites, each housing a Tier-1 GNSS reference station co-located with two calibration-grade corner reflectors (CRs). The latter are strategically positioned to account for both the ascending and descending tracks of SAR satellite missions, including the ESA’s Sentinel-1. As of June 2021, CyCLOPS has reached full operational capacity and plays a crucial role in monitoring the geodynamic regime within the southeastern Mediterranean area. Additionally, it actively tracks landslides occurring in the western part of Cyprus. Although CyCLOPS primarily concentrates on geohazard monitoring, its infrastructure is also configured to facilitate the radiometric calibration and geometric validation of Synthetic Aperture Radar (SAR) imagery. Consequently, this study evaluates the performance of Sentinel-1A SAR by exploiting the CyCLOPS network to determine key parameters including spatial resolution, sidelobe levels, Radar Cross-Section (RCS), Signal-to-Clutter Ratio (SCR), phase stability, and localization accuracy, through Point Target Analysis (PTA). The findings reveal the effectiveness of the CyCLOPS infrastructure to maintain high-quality radiometric parameters in SAR imagery, with consistent spatial resolution, controlled sidelobe levels, and reliable RCS and SCR values that closely adhere to theoretical expectations. With over two years of operational data, these findings enhance the understanding of Sentinel-1 SAR product quality and affirm CyCLOPS infrastructure’s reliability.

Distal phalanx radiographic grading features in long‐toe, underrun heel in Egypt Baladi donkeys (Equus asinus)

SummaryBackgroundLong‐toe, underrun heel conformation is a term referring to a long toe, collapsed frog and atrophied heels in equids, including donkeys. However, data on the radiological evaluation and classification of the long‐toe, underrun heel conformation in the donkey are relatively limited.ObjectivesThe present study aimed to determine the relationship between the dorsal hoof wall angle and the radiological angular and linear features of the distal phalanx in long‐toe, underrun heel conformation in Egypt Baladi donkeys.Study designPost‐mortem collected feet.MethodsForty‐seven front hooves with long‐toe, underrun heels from cadavers were radiographically examined. Lateromedial radiometric parameters included dorsal hoof wall angle, heel angle, distal phalanx angle, distal phalanx solar border angle, coronet angle, axis of the distal phalanx angle, proximal palmar cortex angle, distal phalanx to ground distance, distal phalanx to frog distance, distal phalanx to toe distance, foot length and hoof balance%. Long‐toe, underrun heel cadaver feet were classified into four groups according to the dorsal hoof wall angle (DHWA).ResultsThe DHWA of the first group was less than 58.25°–54° (<58.25°:54°), the second group was less than 54°–52° (<54°:52°), the third group was less than 52°–47° (<52°:47°), and the fourth group was less than 47° (<47°). From the first to the fourth groups DHWA, heel angle (HA), distal phalanx solar border angle (P3BA), distal phalanx angle (P3A), axis of the distal phalanx angle (LP3A), proximal palmar cortex angle (PPCA), distal phalanx to frog distance (P3F) and foot length (FL) were decreased, while the coronet angle (CA), distal phalanx to toe distance (P3T) and hoof balance (HB) percentages were increased. Statistical analysis revealed strong and moderate correlations between DHWA and HA, P3A, P3BA, LP3A, PPCA, P3G, P3F and P3T.Main limitationCadaver feet were collected from different yards and body sizes, the collection of radiographic parameters without trimming and the lack of a record of the work history of these donkeys.ConclusionThis study will assist veterinarians in evaluating the long‐toe, underrun heel conformation during hoof trimming.

Utility of Leaf Area Index for Monitoring Phenology of Russian Forests

Retrievals of land surface phenology metrics depend on the choice of base variables selected to quantify the seasonal “greenness” profile of vegetation. Commonly used variables are vegetation indices, which curry signal not only from vegetation but also from the background of sparse foliage, they saturate over the dense foliage and are also affected by sensor bandwidth, calibration, and illumination/view geometry, thus introducing bias in the estimation of phenometrics. In this study we have intercompared the utility of LAI and other biophysical variables (FPAR) and radiometric parameters (NDVI and EVI2) for phenometrics retrievals. This study was implemented based on MODIS products at a resolution of 230 m over the entire extent of Russian forests. Free from artifacts of radiometric parameters, LAI exhibits a better utilization of its dynamic range during the course of seasonal variations and better sensitivity to the actual foliage “greenness” changes and its dependence on forest species. LAI-based retrievals feature a more conservative estimate of the duration of the growing season, including late spring (9.3 days) and earlier fall (8.9 days), compared to those retrieved using EVI2. In this study, we have tabulated typical values of the key phenometrics of 12 species in Russian forests. We have also demonstrated the presence of the latitudinal dependence of phenometrics over the extent of Russian forests.

Influence of aircraft attitude on fully polarized radiometer and its correction

ABSTRACT As an important load of airborne/spaceborne passive microwave remote sensing, fully polarized microwave radiometer is widely used to the measurement of wind vector and salinity on sea surface. The retrieval of ocean surface parameters requires high accuracy data of radiometer. In recent years, the data correction scheme of fully polarized radiometer is common, but the attitude problem of radiometer is not paid enough attention. This paper establishes a full link transfer model for a fully polarized microwave radiometer, and focus on analysing the impact of aircraft attitude on various parameters. This paper aims to draw researchers’ attention to attitude control of fully polarized microwave radiometer. Through the model established in this paper, the influence of attitude on fully polarized microwave radiometers is clarified and corrected, then rapidly correction can be achieved. Through simulation model, the impact of different attitudes on data can be calculated in advance before flight tests, and can provide guidance for attitude control. Using the corrected data for wind vector analysis, the deviation of wind direction is within 10 ∘ , which also verifies the accuracy of the model in this paper. The model proposed in this paper can achieve fast and accurate correction of radiometer parameters and the error prediction caused by attitude, which provides a strong guarantee for the inversion of sea surface parameters.

Empirical Relation Between Magnetic and Radiometric Survey in Bitumen Area, Ogun State, Nigeria

Abstract One of the vital roles played by both magnetic and radiometric surveys is identification and delineation of mineral deposits. The study area, Imeri, which lies between latitude 6 °45′N to 6 °48′N and longitude 3 °58′E to 3 °59′E, has been established for bitumen deposition. The responses of mineral deposition to different geophysical methods differ from place to place due to variation in climate and bedrock composition. In this study, two geophysical techniques—magnetic and radiometric methods—were adopted to investigate the magnetic anomalous and radiometric flux responses around the bitumen deposit area. The study also intends to establish a model-like relation between the radiometric parameters and the magnetic anomaly observed. Statistical inferences for the established relations were deduced using the t-test at 0.05 significance levels. The result obtained showed that uranium and thorium concentration responses along the two traverses were in good agreement with that of magnetic intensity. The claim was accounted for based on the correlation result, which ranged between 74%–79% and 84%–89% for uranium and thorium, respectively, with magnetic intensity along the two traverses. In order to validate the claim, the t-test was used. The result obtained showed that there exists no significant difference between the two geophysical methods; the result for the t-test has critical value > calculated value (p-values > 0.05). Based on this, the empirical relations were deduced for magnetic anomalous response and radiometric parameters. This work has therefore proven the two techniques to be versatile for bitumen prospecting in the study area.

An Influence of Parameters of the Control Signal of Power LEDs on Their Junction Temperature and Emitted Light

This article presents the method of implementation and the results of experimental investigations illustrating an influence of parameters of the signal controlling the current flowing through power LEDs on their junction temperature and on parameters characterizing the light emitted by them. The measurement system used and the tested power LEDs are described. The results of measurements of the junction temperature of the tested devices, the values of the average value of the power dissipated in the tested devices and the photometric and radiometric parameters of these devices obtained for different values of frequency and the duty cycle of the signal controlling the current flowing through the tested diodes are presented and discussed. It is shown that the operation of the considered semiconductor devices is more effective at low frequency values. The possibility of adjusting the optical parameters of the power LEDs in the considered range of frequency and the duty cycle adjustment is assessed. Additionally, the measured waveforms of the current supplying the tested LEDs is shown. The influence of the parasitic capacitances of the tested devices is discussed. On the basis of the obtained investigation results, some recommendations for the designers of lighting systems can be formulated. In order to obtain an almost linear dependence of the illuminance on the duty cycle, the values of frequency not exceeding 10 kHz should be used.

高分一号宽幅多光谱影像辐射定标偏差及其植被指数影响

PDF HTML阅读 XML下载 导出引用 引用提醒 高分一号宽幅多光谱影像辐射定标偏差及其植被指数影响 DOI: 10.5846/stxb202205241462 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划课题项目2019YFB2102004）；福建省自然科学基金项目（2021J011190）；厦门理工学院高层次人才项目（4010520004）；江西省水利科技项目（202224ZDKT11） Radiometric calibration bias of the Gaofen-1 WFV multispectral imagery and its influence on vegetation index Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:自2013年4月在轨运行以来，高分一号（GF-1）宽幅（WFV）多光谱相机已实现持续对地观测，为包括生态学在内的相关研究领域与行业应用提供了丰富的数据源。当前场地定标频次偏低以及定标参数更新、发布滞后的现状，一定程度上影响了GF-1 WFV多光谱数据的定量应用。然而，现有文献仅在数据预处理流程中谈及对GF-1 WFV影像的辐射定标处理，很少讨论定标参数选取不当甚至误用产生的可能影响。基于已公布的辐射定标参数（2014-2021年）和4景GF-1 WFV Level1A级影像产品数据，重点围绕辐射定标偏差及其对多光谱波段星上反射率和常用植被指数的影响等展开模型分析和讨论。结果显示：即使两个相邻年份间，在多数情况下误用辐射定标参数会导致不可忽视的波段星上反射率相对偏差；进而给不同类型植被指数的实际应用带来不同程度的挑战。因辐射定标偏差的影响，常用的两波段归一化型植被指数在监测稀疏植被覆盖区时会存在明显的误差；而对高植被覆盖区的监测时采用两波段简单比值型植被指数将面临更大的挑战。针对存档GF-1 WFV Level1A数据的应用需求，提出利用时间距离加权的线性内插法来修正基于公开定标参数的辐射定标结果，并通过案例分析表明了该处理方法的有效性。最后，希望研究结果能引起普通用户对卫星遥感影像辐射定标的关注和重视。 Abstract:Since its on-orbit operation in April 2013, the wide field of view (WFV) sensors onboard Gaofen-1 (GF-1), where "Gaofen" means high resolution in Chinese, have continuously collected multispectral imagery of the Earth's surface. The GF-1 WFV sensors have provided abundant data sources for many fields including ecology. The fact that insufficient site calibration (i.e. once a year) as well as the updates lag of calibration parameters might limit the quantitative application of the GF-1 WFV imagery to a certain extent. However, current literature has only mentioned radiometric calibration of the GF-1 WFV images as a pre-processing procedure, whereas has rarely discussed the possible impacts caused by improper selection or misuse of calibration parameters. Based on the radiometric calibration parameters published for the GF-1 WFV imagery (from 2014 to 2021) and four scenes of the Level1A data products, the issue on radiometric calibration bias was investigated. Furthermore, impacts of the radiometric calibration bias on the top of atmosphere (TOA) reflectance and on several vegetation indices commonly used were discussed accordingly. It showed that, generally, even the calibration difference between two neighboring years were considered, in most cases, improper selection of the calibration parameters could result in a significantly relative bias in the TOA reflectance. The bias in TOA reflectance further challenged different types of vegetation indices with varying degrees of patterns in practice. In particular, mainly due to the radiometric calibration biases, the obvious errors were more likely in the normalized difference vegetation index based on two bands, for monitoring sparse vegetation coverage area. Actually, the normalized difference vegetation index has been commonly used in assessing vegetation status as well as surface dynamics. At the same time, for monitoring high vegetation coverage area, the simple ratio vegetation index with two bands was possibly confronted with greater challenges. Consequently, to make full use of the GF-1 WFV Level1A products, it is critical to solve the radiometric calibration problems. In this study, a time weighted linear interpolation method was proposed. In the interpolation process for a specific GF-1 WFV imagery, both radiometric parameters obtained closely before and after the imagery acquisition were integrated. A case study suggested the effectiveness of the proposed processing to improve the radiometric calibration of the GF-1 WFV images in Level1A products, as compared against the results obtained merely based on public calibration parameters. Finally, general users should pay much attention to the radiometric calibration of satellite remotely sensed data (e.g., the GF-1 WFV multispectral imagery) for their quantitative applications, as discussed in this investigation. 参考文献 相似文献 引证文献

EFFICIENCY OF COMPUTER NAVIGATION TECHNOLOGY IN TOTAL KNEE REPLACEMENT

We studied the treatment outcomes in 124 patients (102 women and 22 men) aged 51 to 83 years (median 69 [65; 76] years) on 124 knee joints. Patients were divided into 2 groups: the study group – 62 people aged 51 to 83 years (median – 69.1 [64;74] years), who used computer navigation, and the comparison group – 62 people aged 56 to 83 years (median 69 [65;78] years), in which surgical in-tervention was performed according to the standard technique. Long-term results were studied in terms of 3 to 36 months. During the examination, the deformity variant was determined, radiometric parameters of the knee joints were measured using the Knee Society Score (KSS), Functional Knee Society Score (FKSS), and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) scales. Also, functional stress tests were performed to assess the stability of the knee joint in the frontal plane and functional indicators of the range of motion. After surgery, in the study group, the WOMAC values decreased by 5.90 times and the median value to 11 [8;15] points (p < 0.001), in the comparison group they decreased by 4.81 times to 13.5 [8;16] points (p < 0.001), KSS in-creased by 3.88 times. Median KSS in the study group increased 3.91 times and reached 86 [84;95] points (p < 0.001), in the comparison group it increased 3.86 times only to 85 [77;95] points (p < 0.001). FKSS data increased by 1.75 times. The median FKSS in the study group increased 2.08 times and reached 94 [85;99] points (p < 0.001), in the comparison group it increased 1.60 times only to 93 [83;95] points (p < 0.001).

Radiometric Correction Model and Land Cover Classification of Snow-Covered Terrains for ICESat-2 Photon-Counting Lidar

The signal strength is a fundamental parameter in radiometric applications for satellite lidars. Different from full-waveform lidars, photon-counting lidars cannot record the returned signal strength but only respond to the presence of the photon event and may miss some returned photons due to the dead time effect, i.e., introduce radiometric distortion. Based on the lidar equation and the response mechanism of photon-counting detectors, we propose a radiometric correction model to remove the impact of the nonlinear response and dead time of detectors for the photon-counting lidar borne on ICESat-2. The returned signal photon number is corrected by the proposed model with respect to the photon event number per shot (PNPS) and surface slope derived from ATL03/ATL08 products. Then, the optical throughput calibration factor of ICESat-2 is obtained from ATL06 products over high Antarctic plateau where has given reflectance and clear atmosphere, which is generally equal to 0.52. The atmospheric attenuation induced by the molecular, cloud, and aerosol is calculated from ATL09 products. In addition, the corrected radiometric parameters including the calculated surface reflectance and apparent surface reflectance (ASR) are applied to classify land cover types along laser tracks over snow-covered terrains. The results indicate that the signal strength and calibration constant are reliable after corrections, but the atmospheric attenuation is sometimes inaccurate, which further influences the derived surface reflectance. In classifications, the overall accuracy and Kappa coefficient based on the corrected ASR can achieve the best classification results with 88.80% and 0.69. The proposed radiometric correction model is very essential to radiometric applications for photon-counting lidars such as ICESat-2, especially for data captured on ice and bare land with relatively high reflectance.

Hybridization of statistical machine learning and numerical models for improving beam, diffuse and global solar radiation prediction

Prediction, separation, and improvement of beam (Hb), diffuse (Hd), and global solar radiation (H) using an efficient Gumbel probabilistic model (GP) and hybridization of GP with auto-regression integrated moving average (ARIMA) is essential in regions of Southern Africa and the Middle East. This is because, most of the inhabitants of these localities are not connected to the national grid due to extreme cost implications, frequent power outages, and in most cases, unavailability of the national power supply; as well as the fact that most government meteorological stations are technologically or financially unable to routinely measure these radiometric parameters in most metropolitan cities, developing cities, and remote villages, where there is a severe need for electricity. Although the prediction of H has many advantages in adapting and deploying clean and affordable energy infrastructure through solar photovoltaic (PV) systems, the separation of H into Hb and Hd will further increase cleaner and more affordable systems like solar PV thermal/concentrators, which require Hb for its use. In this era of climate change, Hb, Hd, and H information are needed to detect and adapt climate mitigation plans in places adversely affected by climate change and global warming externalities. Eight different configurations of input combination elements were assembled to stimulate their hybrid evolutionary ARIMA-GP controlled, swapped model through the instrumentality of generalized solar meteorological datasets needed for modeling. The result revealed that the swapped ARIMA models outperformed the controlled and controlled ARIMA models using Gumbel's numerical approach. The best min beam and diffuse irradiance frocontrolled ARIMA models were probabilistically optimized using the Gumbel (GP) probabilistic model to produce ARIMA-GP. From the evaluations of the error metrics, the ARIMA-GP models outperformed the swapped and controlled ARIMA models, as well as the Gumbel models used to separate HB and Hd from H. The selected best performing models produced the RMSE-induced decrease and increase in R2 of 73.73% and 15.25% respectively for GSRML-GP3 (model H), 71.71%, and 14.19% for DSRML-GP5 (model Hd), and 61.91% and 11.70% for DNIML-GP5 (model Hb). These high values of the percentage improvement of the suitable model obtained for the Hb, Hd, and H modeling suggest that the proposed hybrid evolutionary ARIMA-GP model can be adopted to improve the prediction of solar beam, diffuse and global radiation in any region of the world, as the input parameters incorporate the data sets on geo-climatic conditions needed for global modeling. This study also suggests that it is more realistic to use the generalized functional forms GP and ARIMA-GP to separate Hb and Hd from the parameter H and also to generate their corresponding coefficients in the studied regions than applying empirical and machine learning models consolidated in the literature. The proposed ARIMA-GP models are sufficient as a valid evolutionary hybrid model that will accelerate a holistic understanding of the solar resources available in the selected regions and beyond, as well as spread the application of solar photovoltaic/thermal technologies within these countries.

Radiometric Parameters of the Forearm in Traumatic Instability of the Distal Radioulnar Joint in Children

Background. At present, the literature describes in sufficient detail the use of various methods of X-ray examination of the bones of the forearm in the diagnosis of distal radioulnar joint instability (DRUJI), but there are no data on radiometric parameters for DRUJI of traumatic origin in children. Quantitative diagnostics becomes mandatory for determining the tactics of treating DRUJI of traumatic origin in children.
 The purpose of study to analyze the radiometric parameters of the distal forearm in case of DRUJI of traumatic origin in children to plan the method of surgical treatment.
 Мethods. The paper presents an analysis of the results of X-ray examination of 23 children with instability of the distal radioulnar joint of traumatic origin aged 9 to 17 years (mean age 14.212.5 years) the main group. For comparison, radiographs of the contralateral forearms of the same patients were analyzed the comparison group (23 children), and radiographs of the forearm of 69 pediatric patients without signs of DRUJI (control group). On radiographs in the anteroposterior and lateral projections, the following radiometric parameters were evaluated: radioulnar and volar angles, radioulnar index, radioulnar distance, and the difference between the radioulnar distances of both forearms.
 Results. In 19 patients of the main group, a positive variant of the radioulnar index with dislocation of the head of the ulna was revealed, while the indicators of the radioulnar and volar angle were characterized by variability in values. The average values of radiometric parameters of DRUJI in children without bone-traumatic changes of the forearm are comparable to normal values in adults.
 Conclusions. In children with DRUJI of traumatic origin, various changes were revealed radiometric indicators of the distal parts of the bones of the forearm, which depend on the type of forearm fracture. In a particular pediatric patient with DRUJI of traumatic origin, these indicators reflect the biomechanical features of the wrist joint, which must be taken into account when planning surgical intervention and predicting the recovery of the anatomy and function of the forearm.

U-Net for Medical Imaging: A Novel Approach for Brain Tumor Segmentation

In medical imaging, brain tumor segmentation is critical. The segmentation of a brain tumor might be done manually or automatically. Finding anomalies in magnetic resonance imaging (MRI) images manually is time-consuming and complex. Automatic segmentation, on the other hand, is incredibly accurate and time-saving. Any technique that can detect a brain tumor early would improve the diagnosis method. As a result, the number of cases of death will decrease. MRI (Magnetic Resonance Imaging) scans have proven to be quite helpful in the detection and segmentation of brain tumors in recent years. MRI images can aid in the detection of a brain tumor. MRI scans can detect abnormal tissue growth and blood blockages in the neurological system. The U-Net model is being used to segment the brain tumor region. The U-Net model is simply a more advanced version of CNN's algorithm. The U-Net model was created to segment biological pictures. We create a 3D U-Net design to segment the brain tumor infection zone in this paper. We combine clinical data with novel radiometric parameters based on the geometry, position, and shape of the segmented tumor to estimate each patient's survival length. The loss graph and accuracy graph are given together with the scores. Finally, we run the tests on various original photographs using the masks that correspond to them.

Spatial Distribution of Radiometric and Dosimetric Parameters in Soil Samples from Selected Areas in Bayelsa State, Nigeria

Radiation from radioactive materials/radionuclides in the environment enhanced by anthropogenic activities is presently of a great concern globally. The objective of this study is to determine the radiometric and dosimetric parameters from soil samples collected randomly from the study area of Bayelsa State, Nigeria. The samples were prepared using standard methods and analyzed with a high resolution Hyperpure Germanium Detector configuration (HPGe). The results showed the clay samples to have higher activity concentration to the sands samples with activity concentration of clay samples ranging between 68.99±9.05 –189, 42±21.11Bq/kg and the sand samples with activity concentration range of 17.95±5.87 – 38.59±7.43Bq/kg. The activity concentration spatial distribution map in clay lithologies showed 2 peak values trending north-west, while the sand lithology showed a single peak central distribution. The result also showed the values of the absorbed doses with the 8 clay samples values ranging between 59.09 - 155.25nGy/h and sand samples values between 17.90 – 33.92nGy/h. The spatial distribution of the dose showed 2 peak central distribution in clay samples and north-east trending distribution of high peak values for samples with sand lithologies. In addition, the results showed an effective absorbed dose of range of 0.235-0.0616mSv/y for samples with clay lithology and 0.0071-0.0135mSv/y for samples with sand lithology The activity concentration of all the samples studied are below the 1000Bq/kg international reference limit for Radium 226, Thorium 232, uranium 238 and 10,000Bq/kg for potassium 40. The absorbed dose rate and annual effective absorbed dose are also below the international reference limits published by ICRP, 2007 and UNSCEAR, 2000 publications. Also, effective activity maximum limit of 370Bq/kg for input raw materials for public building is not exceeded.

Metrological Traceability and Crucial Detector Characteristics for UVC Metrology in UVGI Applications

Ultraviolet-C (UVC) radiation-based sanitization has globally gained enormous importance in the current COVID-19 (caused by SARS-COV-2 virus) pandemic situation. The effectiveness of radiation sanitization is quantified in terms of ‘radiation dose’, which in turn is derived from a radiometric parameter ‘irradiance’, measured using UVC radiometer. Metrological traceability of irradiance/dose measurement is essentially required for achieving requisite accuracy of measurements, and hence germicidal efficacy. In the present article, the derivation of traceability for irradiance measurement using UVC radiometer is demonstrated. The critical conditions to be considered while using detector/radiometer for measuring UVC irradiance/dose in practical conditions are elaborated, avoiding which, significant errors in the UVC irradiance/dose may arise, and hence, may compromise the performance of the Ultraviolet Germicidal Irradiation (UVGI) devices.

Prediction of global solar radiation potential for sustainable and cleaner energy generation using improved Angstrom-Prescott and Gumbel probabilistic models

Predicting and improving global solar radiation models is important in Nigeria because, most government meteorological stations are unable to continuously set-up or measure this radiometric parameter in most metropolitan cities and remote villages where there is a severe need for electricity. This is because most locations are not connected to the national grid due to high cost implications. Global solar radiation (H) prediction has a great deal of benefits in adapting and implementing clean and sustainable energy infrastructure, and much more in detecting and adapting climate mitigation measures in locations affected by climate change externalities. The new Gumbel (GP) probabilistic model applied in this paper is renowned for its high prediction power and low input requirements on the coefficients of the Angstrom-Prescott (AP) model used by researchers to predict global solar radiation since 1940. This study's foremost intention was to investigate ways of generating sustainable and cleaner energy by using coefficients of the AP model in order to accelerate the greener economy in Nigeria. As such, the accuracy and suitability of 36 existing and developed empirical AP models, as well as 11 fitted GP models, were evaluated to estimate H in different climatic regions of Nigeria. The results revealed that AP models fitted with generalized datasets outperformed the 10 location-based models considered in this work and the 7 models selected from literature, however, the GP model outperformed all empirically fitted models. The model established by GP (M13) was used to optimize AP models with poor performance and those selected from literature. This study suggests that it is more realistic to apply the generalized and GP model to predict global solar radiation and generate AP estimation coefficients across Nigeria than using empirical modeling and AP estimation coefficient. This is illustrated by the high prediction accuracy, little or no instrumentation network, and the computational effort for a GP model over an instrumentation network required to generate sunshine hour datasets required to implement AP model predictions. The proposed GP model is sufficient as a valid predictive model that will promote a holistic understanding of the available solar resources in Nigeria and disseminate the application of solar photovoltaic technologies within the country.

СРАВНИТЕЛЬНАЯ ХАРАКТЕРИСТИКА ДИСТАЛЬНЫХ ОСТЕОТОМИЙ СРЕДНИХ ПЛЮСНЕВЫХ КОСТЕЙ ПРИ МОЛОТКООБРАЗНОЙ ДЕФОРМАЦИИ ПАЛЬЦЕВ СТОПЫ И ЦЕНТРАЛЬНОЙ МЕТАТАРЗАЛГИИ

Aim of the study. To compare the effectiveness of distal extension-shortening osteotomy (DESO) of the metatarsals and Weil-osteotomy in the surgical treatment of the middle hammer toe deformity and central metatarsalgia. Treatment outcomes were studied in 80 patients (75 women and 5 men) aged 31 to 79 years (median – 57 [52; 64] years) on 90 feet. The patients were divided into 2 groups: the study group – 32 people, where the DESO was used, and the comparison group – 48 people, in which a typical Weil-osteotomy was performed. Long-term results were studied within 6 to 46 months (median – 24 [10; 33] months). During the examination, a variant of hammertoe deformity was determined, radiometric parameters of the forefoot were measured, the Visual Analogue Scale (VAS) for pain and the American Orthopaedic Foot and Ankle Society Lesser Toe Scale (AOFAS—II—V) were used. After surgery in the study group, the median VAS decreased to 1 [0; 1] points (p < 0,001), in the comparison group — up to 2 [0; 3] points (p < 0,001). Median AOFAS—II—V in the study group increased by 2,2 times and reached 93 [90; 95] points (p < 0,001), in the comparison group it increased only to 85 [73; 90] points (p < 0,001). The received data indicate a higher efficiency of DEMO for hammer toe deformity and central metatarsalgia compared to the standard Weil-osteotomy. The DEMO technique provides a pronounced reduction in pain syndrome (by 6 times), creates conditions for easy elimination of hammer toe deformity, improves the functional state of the forefoot by more than 2,2 times (according to AOFAS—II—V) and obtains positive treatment outcomes in 94,4 % of cases.

Corrective Intertrochanteric Osteotomy of the Femur for Aseptic Necrosis of the Femoral Head after Bloodless Reduction of Congenital Dislocation in School-Age Children

The immediate results of treatment of 72 children aged 7 to 12 years with aseptic necrosis of the femoral head after bloodless reduction of congenital hip dislocation were analyzed. When treating patients, the following types of surgical treatment were used:extra-articular or open centering of the femoral head with intertrochanteric-torsion-varizing or devarizing and rotational osteotomy of the femur with bringing down the greater trochanter in the caudal direction. In all patients, pain and lameness disappeared, internal rotation of the lower extremities when walking, and the range of motion in the hip joint improved. Improved radiometric parameters characterizing the ratio of the acetabulum and the head of the femur and the angular values of the hip joint and proximal femur.

Frequency of Acetabulum Retroversion Formation after Reorienting Pelvic Osteotomies in Children Over 7 Years Old with Developmental Dysplasia of the Hip

Background. One of the reasons for the development of the “pincer” type of femoroacetabular impingement are various reorienting pelvic osteotomies, which are widely used in the treatment of children with developmental dysplasia of the hip (DDH).The aim of the study was to evaluate the frequency of formation of retroversion of the acetabulum after reorienting pubic-iliac, iliac-sciatic and triple pelvic osteotomies in children over 7 years old with DDH I–II degree according to Crowe.Material and Methods. The retrospective study is based on the results of radiometry of 60 patients (69 hip joints) at an average age of 11.6±2.9 years with DDH I–II degree according to Crowe who underwent surgical treatment in 2014-2016. The patients were divided into three groups of 20 patients each. Group I underwent an iliac osteotomy. Group II underwent an ilio-sciatic osteotomy. In group III patients, the acetabulum was reoriented by triple (pubo-ilio-sciatic) pelvic osteotomy. In addition to standard radiometry of the hip joints, the following indicators were evaluated: signs of acetabular retroversion (“cross-over”, “posterior wall”, “ischial spine”), as well as the index of acetabular retroversion (ARI).Results. The assessment of the main radiometric parameters of the spatial position and the correction value of the acetabulum was carried out at least 36 months after the surgical treatment. There were no statistically significant differences in the radiometric parameters of the spatial orientation of the acetabulum in group I and II patients (p0.05), except for the degree of bone coverage, which was significantly higher in group II patients (p0.05) than in group II patients, which indicated the presence of hypercorrection. In patients of group III, the values of the above-mentioned indicators varied within the physiological values. Retroversion of the acetabulum was observed in more than half of the patients in group I and in almost all patients in group II. In group III patients, acetabular retroversion was observed in only 3 patients.Conclusion. In the vast majority of cases, a double pelvic osteotomy (pubo-iliac and ilio-sciatic) leads to the formation of hypercorrection of the acetabular fragment and its retroversion in comparison with a triple pelvic osteotomy. The pathological orientation of the acetabulum, despite the achieved stability of the hip joint, can be a morphological substrate for the development of femoro-acetabular impingement and, as a result, coxarthrosis. In the treatment of children with DDH over 7 years old the operation of choice is a triple pelvic osteotomy.

Compact Modelling of Electrical, Optical and Thermal Properties of Multi-Colour Power LEDs Operating on a Common PCB

This paper concerns the problem of modelling electrical, thermal and optical properties of multi-colour power light-emitting diodes (LEDs) situated on a common PCB (Printed Circuit Board). A new form of electro-thermo-optical model of such power LEDs is proposed in the form of a subcircuit for SPICE (Simulation Program with Integrated Circuits Emphasis). With the use of this model, the currents and voltages of the considered devices, their junction temperature and selected radiometric parameters can be calculated, taking into account self-heating phenomena in each LED and mutual thermal couplings between each pair of the considered devices. The form of the formulated model is described, and a manner of parameter estimation is also proposed. The correctness and usefulness of the proposed model are verified experimentally for six power LEDs emitting light of different colours and mounted on an experimental PCB prepared by the producer of the investigated devices. Verification was performed for the investigated diodes operating alone and together. Good agreement between the results of measurements and computations was obtained. It was also proved that the main thermal and optical parameters of the investigated LEDs depend on a dominant wavelength of the emitted light.