Polynomial Trend Research Articles

Thermography signs of lung inflammation

The purpose of the study was to find out if infrared thermography of the thorax is the method to select the patients with lung inflammationMaterial, methods: Thermograms were accumulated and processed in the «TVision» cloud storage («Dignosis», Russia). Special regions of interest (ROI) were automatically created: 1. on the front and back of the thorax roughly in the projection of the upper lobe (ULP) and the lower lobe (LLP) of the lung; 2.e lines on the front surface of the thorax. Two types of temperature gradients were calculated: between ULP and LLP (by subtraction mean temperature in LLP from mean temperature in ULP) (ΔT1); between both ULP and both LLP on the back of the thorax (ΔT2). Approximation confidence value for the polynomial trend line (R²) along the marked lines on the front surface of the thorax also calculated. Totally 489 thermograms, were analyzed, included 337 from healthy patients (group 1) and 152 from patients with confirmed diagnosis of lung inflammation (group 2)Results: R² value was higher in the group 1 compare to group 2 (0.58 ± 0.16 vs 0.3 ± 0.2, p < 0.05). ΔT1 value was negative only in patients from group 2, as well as ΔT1 value greater than 0.4 °C.Conclusion: three independent thermographic criteria suitable for detecting lung inflammation were found, so infrared thermography is the valuable method for screening this pathology.

Seven Decades of Coastal Change at Barter Island, Alaska: Exploring the Importance of Waves and Temperature on Erosion of Coastal Permafrost Bluffs

Observational data of coastal change over much of the Arctic are limited largely due to its immensity, remoteness, harsh environment, and restricted periods of sunlight and ice-free conditions. Barter Island, Alaska, is one of the few locations where an extensive, observational dataset exists, which enables a detailed assessment of the trends and patterns of coastal change over decadal to annual time scales. Coastal bluff and shoreline positions were delineated from maps, aerial photographs, and satellite imagery acquired between 1947 and 2020, and at a nearly annual rate since 2004. Rates and patterns of shoreline and bluff change varied widely over the observational period. Shorelines showed a consistent trend of southerly erosion and westerly extension of the western termini of Barter Island and Bernard Spit, which has accelerated since at least 2000. The 3.2 km long stretch of ocean-exposed coastal permafrost bluffs retreated on average 114 m and at a maximum of 163 m at an average long-term rate (70 year) of 1.6 ± 0.1 m/yr. The long-term retreat rate was punctuated by individual years with retreat rates up to four times higher (6.6 ± 1.9 m/yr; 2012–2013) and both long-term (multidecadal) and short-term (annual to semiannual) rates showed a steady increase in retreat rates through time, with consistently high rates since 2015. A best-fit polynomial trend indicated acceleration in retreat rates that was independent of the large spatial and temporal variations observed on an annual basis. Rates and patterns of bluff retreat were correlated to incident wave energy and air and water temperatures. Wave energy was found to be the dominant driver of bluff retreat, followed by sea surface temperatures and warming air temperatures that are considered proxies for evaluating thermo-erosion and denudation. Normalized anomalies of cumulative wave energy, duration of open water, and air and sea temperature showed at least three distinct phases since 1979: a negative phase prior to 1987, a mixed phase between 1987 and the early to late 2000s, followed by a positive phase extending to 2020. The duration of the open-water season has tripled since 1979, increasing from approximately 40 to 140 days. Acceleration in retreat rates at Barter Island may be related to increases in both thermodenudation, associated with increasing air temperature, and the number of niche-forming and block-collapsing episodes associated with higher air and water temperature, more frequent storms, and longer ice-free conditions in the Beaufort Sea.

The dynamics of alterations and prognostic models of levels of morbidity of urban and rural population of the subject of the Russian Federation

The article presents data of analytical study of morbidity indices of urban and rural population of the Republic of Tatarstan. The dynamics of population morbidity rate in the Republic of Tatarstan is characterized by steady trend of decreasing of indicator and is described by polynomial trend in both absolute and relative indices. The highest rates of increase in population morbidity were mainly observed until 2010. The maximal periods of decreasing or slowdown of rate increasing were characteristic in 2011-2019. In the structure of population morbidity, the highest percentage fell on diseases of respiratory and circulatory systems, injuries, poisoning and some other consequences of external causes impact that was typical both for the Republic of Tatarstan in whole and its rural territories. In general, morbidity rate of urban population was higher than that of rural population. This difference was statistically significant, but growth rate of number of cases in rural territories outstripped growth rate of number of cases in urban territories and was higher than in the Republic of Tatarstan in whole, but was not statistically significant. The medium-term prognosis of dynamics of population morbidity rate in the Republic of Tatarstan in whole demonstrated that, all other things being equal and taking into account current trends, decrease in number of registered patients with diagnosis established for the first time in life can be expected to 2874.2 thousand of population by 2024 (that is less as compared with 2019 level by 242.4 thousand of population, or by 7.8%) and number of registered patients with diagnosis established for the first time in life to 70217.8 per 100 thousand of population (which is less as compared with 2019 level by 9680.8 per 100 thousand of population, or by 12.1%).

Efficacy of Non-Linear Approach in the Study of Ozone Layer Depletion

The stratosphere is one of the constituents of thermal structure of the atmosphere. The maximum concentration of ozone is found at the stratospheric region where it is interacted by many species including chemical and physical processes. Atmosphere as a whole is an open system that is regarded as a non linear system and that seems to be complex. Therefore, a non-linear trend is plausible to explain phenomenon of ozone layer depletion (OLD).
 In this manuscript we have paid our attention in the analysis of the major portion of historic data on stratospheric O3based on ground-based measurements by the Dobson Spectrophotometer. In this communication we have estimated parameters for describing non-linearity in the process using polynomial trend functions and predicted values are calculated for the period from 1960 to 1999. Future values for ozone depths are computed till 2006 and compared with the minor portion of the data set.

The Use Of Payment Cards In Kazakhstan: Analysis And Forecast

The aim of the study is to analyze and forecast the use of payment cards for making non-cash payments through national payment systems in Kazakhstan. Based on this goal, a hypothesis was put forward that in Kazakhstan, there is a relationship between the number of payment cards and the volume of non-cash payments. This hypothesis was confirmed because of the study. The information base of the study was the data on payment cards, which were taken from the Statistical Bulletin of the National Bank of the Republic of Kazakhstan. Hypothesis testing was carried out using correlation analysis for three periods: 2009, 2016, 2020. The method of finding Pearson’s correlation in the SPSS program was used. The results showed a downward change in the relationship between the selected indicators and the amount of funds transferred over time. Also, in this study, a forecast was made for 2021-2023 for the indicators under consideration. To make a forecast for the indicators under consideration, a graphical method (polynomial trend line) was used. The resulting forecast shows the growth of cardholders and, consequently, the spread of the number of payment cards among the population in 2021-2023. The practical significance of this study is that the proposed methodology can help predict the dynamics of payment cards in any country in the world. Recommendations are also given for further improving the financial system, since increasing the transparency of monetary circulation in small-and-medium sized businesses will lead to a positive result in the implementation of the program for universal declaration of income in 2025.

Predicting regional airline traffic using a polynomial trend line

Predicting regional airline traffic using a polynomial trend line

Analysis of traumatism in officers of the Armed Forces of the Russian Federation and the Republic of Belarus (2003–2020)

Relevance. Traumatism in military personnel is defined as injuries and their consequences occurring over a specified period of time, usually over a year. Trauma rates in the Armed Forces (AF) are important for occupational safety.Intention: To compare trauma rates in officers of the AF of Russia and Belarus over 18 years (2003–2020).Methodology. Medical reports on the state of health of personnel and activities of the medical service were selectively analysed according to Form 3 / MED from those military units where no less than 80% of the total number of officers of the AF of Russia and Belarus served. Blocks of injuries are consistent with Chapter XIX «Injuries, poisoning and certain other consequences of external causes» of the International Statistical Classification of Diseases and Problems Related to Health, 10th revision (ICD-10). Injuries were calculated per 1000 officers (‰), mortality - per 100 thousand officers.Results and Discussion. Among officers of the Russian AF and Belarusian AF in 2003–2020, there were observed average annual rates of injuries (17.25 ± 1.33) and (13.37 ± 1.43) ‰, respectively; hospitalizations with injuries (10.68 ± 0.64) and (7.13 ± 0.81) ‰ (p < 0.01); work days lost (344.4 ± 26.4) and (299.9 ± 25.6) ‰; dismissal rates (0.356 ± 0.068) and (0.118 ± 0.022) ‰; and injury-related mortality (47.24 ± 3.71) and (33.37 ± 5.40) (p < 0.05) per 100 thousand officers of the Russian AF and Belarusian AF, respectively. The congruence (consistency) of trends for injuries, hospitalizations and work days lost among officers of the AF of Russia and Belarus was considered positive and strong, while mortality trends were positively and moderately consistent, thus indicating effects of similar (unidirectional) military occupational factors. Polynomial trends in the dynamics of injuries, hospitalizations, work days lost and mortality among officers of the AF of Russia and Belarus with high determination coefficients showed a decrease. Injuries to the head (Block 1 according to ICD-10), injuries to the hip and lower limbs (Blocks 8-10), injuries involving multiple body regions (Block 11), and injuries to the shoulder girdle and upper limbs (Blocks 5-7) were of high military epidemiological significance for officers of the AF of Russia and Belarus. In addition, sequelae of injuries, of poisoning and of other consequences of external causes (Block 22) turned out to be significant for the Russian AF officers, and injuries to the thorax (Block 3) were significant for the Belarusian AF officers. The above blocks accounted for 88.6 and 85.5% of assessed military epidemiological significance among Russian and Belarusian AF officers, respectively.Conclusion. Traumatism can be managed and is not limited to medical issues. Various military professionals should be actively involved in the analysis of the causal relationships of injuries and their prevention. For example, among officers of the AF of Russia and Belarus injuries often occur during physical training and sports (9.8 and 6.1%, respectively) and during off-duty time (40.4 and 61.2%, respectively).

Built for active travel? Investigating the contextual effects of the built environment on transportation mode choice

The study investigates the role of the built environment attributes and their contextual effects on travel behaviour. The study utilized a dataset of 4739 respondents elicited from an online survey distributed in Hamilton City, Canada. A Nested Logit (NL) model and a quadratic polynomial trend surface are employed to spatially investigate the determinants influencing mode choice behaviour. The study contributes to our understanding of how geography moderates the impact of built environment attributes on mode choice behaviour. Socioeconomic demographics are found to play a pivotal role in explaining Hamiltonians' mode choice behaviour. For built environment attributes, sidewalk density is positively associated with walking and public transit use. Moreover, bike lane density is positively associated with biking and negatively associated with public transit use. Regarding land-use entropy (mix), the results show that high land-use entropy is negatively associated with choosing the car as a passenger travel mode. From a contextual perspective, the results affirmed that the influence of built environment attributes is not equally efficacious across the city. Improving the built environment attributes across the city reveals a substantial increase in walking and biking while decreasing the probability of choosing other modes. However, it is noteworthy to mention that the influence of improving the built environment is not homogeneous over geography.

Novel 2D velocity estimation method for large transient events in plasmas

Dynamics of fast transient events are challenging to be analyzed with high time resolution. Such events can occur in fusion plasmas such as the filaments during edge-localized modes (ELMs). In this paper, we present a robust method-the spatial displacement estimation-for estimating the displacements of structures with fast dynamics from high spatial and time resolution imaging diagnostics [e.g., gas-puff imaging (GPI)] with sampling time temporal resolution. First, a background suppression method is shown, which suppresses the slowly time-evolving and spatially non-uniform background in the signal. In the second step, a two-dimensional polynomial trend subtraction method is presented to tackle the remaining polynomial order trend in the signal. After performing these pre-processing steps, the spatial displacement of the propagating structure is estimated from the two-dimensional spatial cross-correlation coefficient function calculated between consecutive frames. The method is tested for its robustness and accuracy by simulated Gaussian events and spatially displaced random noise. An example application of the method is presented on propagating ELM filaments measured by the GPI system on the National Spherical Torus Experiment spherical tokamak.

Effect of land-use change along\xa0altitudinal\xa0gradients on soil micronutrients in the mountain ecosystem of Indian (Eastern) Himalaya

Management of soil micronutrients for better crop production needs a sound understanding of their status and causes of variability. This is more relevant for acid soils of the mountain ecosystem of Eastern Himalaya (Northeast India). We assessed the status, and the effect of land uses along altitudinal gradients (14 to 4090 masl) on soil properties and micronutrient concentrations (DTPA extractable Fe, Mn, Cu, and Zn) across the region. Soils varied widely in micronutrient concentrations: Fe from 0.665 to 257.1 mg kg−1 while Mn, Cu, and Zn from traces to 93.4, 17.1, and 34.2 mg kg−1, respectively. On conversion of evergreen forests (EF) to upland agriculture (Shifting—SC and Settled—SA) and plantation (PH), Mn, Cu, and Zn concentrations decreased significantly from 30.5, 1.74, and 2.13 mg kg−1 to 6.44–17.8, 0.68–0.81, and 1.06–1.42 mg kg−1, respectively. Grassland (GL) and lowland paddy (LP) had comparable Fe, Mn, and Cu concentrations (except Zn). Degradation of EF to scrubland (SL) recorded the lowest Mn (5.91 mg kg−1), Cu (0.59 mg kg−1), and Zn (0.68 mg kg−1) concentrations. Fe concentration was however increased in degraded SL (+ 73%) over EF (48.7 mg kg−1). The distribution of micronutrients among the land uses was inconsistent and followed the order: (i) Fe: SL > PH > LP > EF > GL > SC > SA, (ii) Mn: EF > GL > LP > PH > SC > SA > SL; (iii) Cu: EF > GL > LP > SC > SA = PH > SL; and (iv) Zn: GL > EF > LP > SC > SA > PH > SL. Four micronutrients responded differently and followed a non-linear, 6th—order polynomial trend along the altitudinal gradients (< 500 to 4100 masl). Peak concentrations of Fe, Mn, and Cu were recorded at 1001–2000 m while Zn was recorded at > 4000 masl. The variability (54–64%) in soil micronutrients was mainly controlled by three key soil properties: acidity, clay, and organic carbon contents. Thus, altitude-specific land-use management holds significance in the distribution of available soil micronutrients in hilly ecosystems.

Blockchain Technology for Secure Accounting Management: Research Trends Analysis

The scope of blockchain technology, initially associated with the cryptocurrency Bitcoin, is greater due to the multiple applications in various disciplines. Its use in accounting lies mainly in the fact that it reduces risks and the eventuality of fraud, eliminates human error, promotes efficiency, and increases transparency and reliability. This means that different economic sectors assume it as a recording and management instrument. The aim is to examine current and emerging research lines at a global level on blockchain technology for secure accounting management. The evolution of the publication of the number of articles between 2016 and 2020 was analyzed. Statistical and mathematical techniques were applied to a sample of 1130 records from the Scopus database. The data uncovered a polynomial trend in this period. The seven main lines of work were identified: blockchain, network security, information management, digital storage, edge computing, commerce, and the Internet of Things. The ten most outstanding emerging research lines are detected. This study provides the past and future thematic axes on this incipient field of knowledge, which is a tool for decision-making by academics, researchers, and directors of research investment programs.

The influence of intellectual capital and innovations on the economic development of the world and national economy

We consider in the study that the existing economic model will inevitably be replaced by a new effective model of creative and competitive economic development. Technological innovations have caused the rapid growth of the world economy. As the result, production costs have been reduced and the profits of corporations in many sectors of the world economy have increased. Innovation is a factor of rise in Kondratiev cycles. Innovations give an impetus to increase the value added of a country’s economy. The article asserts that intellectual capital is the basis and is becoming an increasingly important component of national and world development. The article has investigated in which way innovation activities affect real GDP and has suggested the answer to the question on what stage of the Kondratiev cycles the world economy is. Innovation as an object of intellectual capital is introduced in the form of patents and other intellectual property. We have analyzed the relevant trends for 2004-2020. The research has determined that by 2030, a significant increase in the number of patent applications is expected. The article has examined the dependence of the world real GDP on the number of filed patent applications in the world by constructing trend lines. It has been found that the largest approximation with a coefficient of determination greater than 0.92 is a polynomial trend line, in which the dynamic growth with a small number of patent applications is inhibited by a sharp increase in their number. The research has defined that the phases of the cyber revolution correlate with Kondratiev waves. The modern phase is characterized by the rapid generation and dissemination of innovations. The article has examined the filing of patent applications in the top 20 countries around the world, among which the leading positions are occupied by China, the USA, and Japan. By constructing trend lines, the research has analyzed the dependence of Ukraine’s real GDP on the number of innovations and has shown that there is no such clear dependence. This indicates the raw material orientation of the Ukrainian economy. The article states that it is extremely important for Ukraine to make the transition from the triad model (with state-monopoly capitalism) to the national economic model, which corresponds to the approaches of the people’s capitalism.

Time-varying impact of financial development on carbon emissions in G-7 countries: Evidence from the long history

Financial development has been widely proved to be a key driver of economic growth; however, its environmental impact is still inconclusive, especially for G-7 countries (i.e. Canada, France, Germany, Italy, Japan, the United Kingdom (UK), and the United State (US)). This paper, therefore, investigates the time-varying impact of financial development on carbon dioxide (CO2) emissions for G-7 countries over a long historical period. The study analyzes historical data from 1870 to 2014 for each country using bootstrap time-varying co-integration (TVC) and bootstrap rolling window estimation approaches. In addition, the polynomial trends of the estimated parameters are obtained to observe the relationship between financial development and carbon emissions. The empirical findings reveal that the impact of financial development on CO2 emissions over a long history is M-shaped in Canada, Japan, and the US; inverted N-shaped in France, Italy, and the UK; and inverted M-shaped (W-shaped) in Germany. This empirical evidence opens new directions for policy makers to design comprehensive economic policy for using the financial sector as an economic tool to keep environmental quality at sustainable levels.

Industries in Delhi: Air pollution versus respiratory morbidities

Industrialization has been contributing to the economic development of countries all over the globe but on the other side of the coin, it is also causing deterioration of the environment as well as human health. Air pollution in industrial areas has emerged as a hasten issue in recent years due to its aggravated effects on health and wellbeing. The objectives of the study are to analyze the concentrations of air pollutants (PM10, PM2.5, NO2 & CO) in industrial areas of Delhi and to assess the association among meteorological variables, air pollutants, and respiratory diseases of industrial workers and their family members. To map these pollutants concentration, Kriging and Inverse Distance Weighted (IDW) interpolation techniques were employed. The results showed that several industrial areas were cloaked with all these four pollutants in varied ranges and different seasons. The increase in the number of registered and operating industries in Delhi, and the consequential rise in the air pollutants' concentrations followed the quadratic polynomial trend. Spearman’s rho correlation technique revealed that the respiratory disease entries of workers and their families depicted a statistically strong negative correlation with temperature, rainfall, and wind speeds while a strong positive association with PM2.5, NO2, and CO.

Monitoring the rapid changes in mangrove vegetation of coastal urban environment using polynomial trend analysis of temporal satellite data

Over the last few decades, anthropogenic activities have triggered the rate of change in the function of mangrove ecosystems in coastal urban areas. Satellite imagery provides valuable information for mangrove mapping and monitoring. Metrics derived from the linear regression analysis of spectral indices (SIs) derived from satellites are commonly used for change analysis. This study examines the robustness of the widely used SIs derived from Landsat satellite image to distinguish mangroves and non-mangrove features and identify the non-linear changes over mangrove forest using the polynomial trend analysis. Airborne Visible and Infra-Red Imaging Spectrometer Next Generation (AVIRIS-NG) data was resampled to simulate the spectral-response of the Landsat sensor. One-way analysis of variance (ANOVA) and mutual information (MI) were applied to the simulated data to identify the optimal SIs. Based on the statistical analysis, modular mangrove recognition index (MMRI), modified normalized difference water index (MNDWI) and normalized difference built-up index (NDBI) were identified to delineate the mangrove, inundated and built-up region. Finally, time-series profiles of the identified spectral indices were generated using Landsat-8 (L8) and Landsat-7 (L7) data to analyse the change dynamics of the mangrove vegetation from 2002 to 2019. The proposed methodology was applied to study the changes in mangroves in the coastal areas of Kochi (Ernakulam District, Kerala State, India). The temporal-non-linear changes in the mangrove area were identified based on polynomial regression that revealed abrupt decline (42% decrease) in the mangrove area due to large-scale infrastructure development projects. The proposed approach is easy to implement, which enables the frequent monitoring of extensive mangrove forests.

Comparison of indicators of injuries in military personnel serving on conscription in the Armed Forces of Russia and the Republic of Belarus (2003–2020)

Relevance. Injury indicators in military personnel reflect injuries and their consequences that occur in a certain period, as a rule, over a year. Injury indicators in the Armed Forces (AF) are important for assessing occupational safety.Intention: To compare injury indicators in military conscripts between the Russian Armed Forces and the Republic of Belarus for 18 years from 2003 to 2020.Methodology. We carried out a selective statistical analysis of medical reports on the health status of personnel and the activities of the medical service according to 3/MED form in military units where at least 80 % of the total number of conscripts of the Armed Forces of Russia and Belarus served. Groups (blocks) of injuries in Chapter XIX “Injuries, poisoning and certain other consequences of exposure to external causes” were agreed with the International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10). Injury data were calculated per 1000 military personnel or ‰, mortality rates – per 100 000 military personnel.Results and their Discussion. In the Russian Armed Forces compared to the Belarusian Armed Forces, the average annual injury rates (primary morbidity) of conscripts were (15.91 ± 1.65) ‰ vs (20.23 ± 1.96) ‰, hospitalizations with injuries (14.16 ± 1.29 ) vs (14.50 ± 0.96) ‰, work days lost (303.4 ± 27.0) vs (303.4 ± 27.0) ‰, dismissal due to injuries (0.552 ± 0.066) vs (0.551 ± 0.051) ‰, injury-related mortality (21.96 ± 4.26) vs (24.18 ± 4.29) per 100 000, respectively. As a rule, polynomial trends with high determination coefficients showed a decrease in the levels of injury, hospitalization, work days lost and mortality. Dismissal trends showed decrease in the Russian Armed Forces and increase in the Belarusian Armed Forces. The conscripts of the Armed Forces of Russia and Belarus have a positive statistically significant congruence in indicators of injuries, hospitalizations, work days lost and mortality, which may indicate the influence of the same (unidirectional) factors in the formation of annual indicators. Injuries of the head (Group 1, Chapter XIX by ICD-10), shoulder girdle and upper limbs (Groups 5–7), the area of the hip joint and lower extremities (Groups 8–10), injuries, affecting several areas of the body (Group 11), and the consequences of injuries, poisoning and other external causes (Group 22) are of high military-epidemiological significance for conscripts in the Russian Armed Forces and the Belarusian Armed Forces. These injuries accounted for 78.7 % and 82.8 % of the generalized estimate in the Russian Armed Forces and the Armed Forces of Belarus, respectively.Conclusion. Taking into account the indicators of injuries will allow the medical service to optimize the calculation of forces and assets for treatment and rehabilitation of servicemen with injuries. Injuries are not only a medical problem; it is necessary to involve more extensively military professionals from various services to analyze the cause-and-effect relationships of injuries and develop measures for their prevention.

PERAMALAN INDEKS HARGA SAHAM MENGGUNAKAN ENSEMBLE EMPIRICAL MODE DECOMPOSITION (EEMD)

Stock price fluctuations make investors tend to hesitate to invest in stock markets because of an uncertain situation in the future. One method that can solve these problems is to use forecasting about the stock prices in the future. Generally, the huge size of data non linear and non stationary, and it is difficult to be interpreted in concrete. This problem can be solved by performing the decomposition process. One of decomposition method in time series data is Ensemble Empirical Mode Decomposition (EEMD). EEMD is process decomposition data into several Intrinsic Mode Function (IMF) and the IMF residue. In this research, this concept applied to data Stock Price Index in Property, Real Estate, and Construction from July 1, 2019 to July 30, 2020 as many as 272 data. Based on the results of data processing, as many as 6 IMF and IMF remaining were used as IMF forecasting and the IMF remaining in the future. The forecast was performed by choosing the best model of each IMF component and IMF remaining, used ARIMA and polynomial trend. Keywords: Time Series Data, Stock Price Index, EEMD, ARIMA, Polynomial Trend.

Computational Modeling of Ultrasound C-Scan Imaging Using Transmitted Signal Peak Density

Ultrasound measurement is a relatively inexpensive and commonly used imaging tool in the health sector. The through-transmission process of ultrasound measurement has been extensively evaluated for detecting abnormalities in tissue pathology. Compared to standard imaging parameters such as amplitude and time of flight, quantitative ultrasound parameters in the frequency domain can provide additional details regarding tissue microstructures. In this study, pressure magnitude or amplitude variation in the frequency spectrum of the received signal was evaluated as a potential imaging technique using the spectral peak density parameter. Computational C-scan imaging analysis was developed through a finite element model. The magnitude variation in the received signal showed different patterns while interacting with and without inclusions. Images were reconstructed based on peak density values that varied with the presence of solid structure. The computational results were verified with the experimental C-scan imaging results from the literature. It was found that magnitude variation can be an effective parameter for C-scan imaging of thin structures. The feasibility of the study was further extended to identify the structure’s relative position along with the sample depth during C-scan imaging. While moving the structure in the direction of the sample depth, the pressure magnitude variation strongly followed a second-degree polynomial trend.

Thermal and evaporative resistance measured in a vertically and a horizontally oriented air gap by Permetest skin model

This paper is a study of the correlation of the thermal resistance (Rct ) and the evaporative resistance (Ret ) in vertically and horizontally oriented air gaps by using the portable Permetest skin model. Experiments were done in a climatic chamber; an isothermal condition for Ret tests and non-isothermal condition for Rct tests. Foamed polyethylene air gap distance rings were prepared with a thickness of 2, 4 and 5 mm and their combinations to simulate the air gap distance from 0 to 16 mm which is more than the expected average gap in clothing systems. Test samples were woven fabric of 100 percent cotton, 100 percent polyester and their blends plus 100 percent of polypropylene, all have similar weight and structure. Results showed that with the increasing thickness of the air gap, Rct increased in a polynomial trend and Ret in a linear proportional rate up to 12 mm then started to change due to the effect of free convection and the different properties of materials. The surprising positive observation is that results from the horizontally and vertically oriented air gaps are very similar, and most of the results from the vertical air gap are slightly lower than the results from the horizontal air gap in all materials.

Determining the dissipative properties of a flexible pipeline’s material at stretching in the transverse direction taking its structural elements into consideration

This paper reports an experimental study that determines the dissipative properties of a pressure fire hose, the type of «T», whose inner diameter is 77 mm, under the static load conditions, taking into consideration the structural elements of the hose in the transverse direction. For this study, experimental samples were separated from the different sections of the hose. The study involved both the outer fabric reinforced frame and the internal waterproofing rubber layer of the pressure fire hose. A series of field experiments were carried out while stretching the samples under the conditions of static loading-unloading cycles. The tests included 7 cycles, which were carried out in a two-minute interval for the material of the hose. The study results showed that during the first two to three cycles, the materials manifest a short-term creep that stabilizes under modes 4‒7. The results from experimental research were approximated by polynomial trend lines. The deformation of samples demonstrated the curves that, under the conditions of cyclic loading and unloading, formed hysteresis loops. When analyzing the appropriate curves, it was found that, first, during the first two-three loading-unloading cycles the area of the hysteresis loops decreases, second, the inclination angle of hysteresis loops also decreased during each subsequent loading-unloading cycle. It was established that the dissipation coefficients of the hose material stretched in the transverse direction are significantly reduced under the first three test modes in the range from 0.49 to 0.37. At subsequent tests (cycles 4–7), dissipation coefficients stabilize at the level of 0.18 for the reinforced frame, and 0.316 for the rubber layer