Abstract The study of an effect of iron doping on the structural, microstructural and mechanical properties of sintered iron-doped mullite is presented. The results of phase composition, performed in detail by Mossbauer spectroscopy and XRD analysis, revealed that all added iron was inside the mullite lattice forming the single phase up to 12% by weight of Fe2O3 and 1300 °C. Samples, which were processed at 1550 °C, contained secondary phases, hematite or magnetite, regardless of the amount of added iron. Furthermore, the addition of iron decreases the values of relative linear shrinkage comparing to the values of undoped one (~18%) while the densities of the sintered samples rise as well as their values of microhardness. Even though the density values were not too high (90 TD%), the obtained values of microhardness were excellent, 1634 HV0.1 for maximum iron content due to the characteristic mullite microstructure.
Abstract The structural and morphological properties of iron-doped mullite powders are the subject of the present study. The powders of undoped and iron-doped mullite in the composition range of 3–15 wt% Fe2O3 were synthesized by a combination of sol-gel and combustion methods. The excess of water and urea were introduced in reaction solutions to enhance the copolymerization of aluminum and silicon species. The results of structural characterization revealed that the synthesized mullite powders were amorphous of a hybrid type. The specific surface area of the undoped mullite powder was 262 m2 g-1 with a maximum pore radius (dp) of 2 nm classifying it into mesoporous materials. The addition of iron has reduced the specific surface area, while the pore size value remained the same except for the sample with 3 wt% Fe2O3 (SBET = 278 m2 g-1; dp = 3 nm). The presence of iron caused lowering the temperature of liquid phase formation, while present urea combusted providing the increase of the temperature locally that caused the sintering and formation of agglomerates of smaller particles. However, the results of the particle size analysis are not straightforward. The values of mean volume diameter (D[3,4]) indicated that the particle size increased to 6 wt% Fe2O3 (123.6 μm), and then decreased and for the sample with 12 wt% Fe2O3, it was equal to 96.6 μm. Thus, the added iron contributed to the more uniform particle size distribution. The SEM analysis has also shown the coarse powder particles consisted of the coalesced smaller particles.
In this paper we consider a generalized length spectrum in the case of compact symmetric spaces generated as quotients of the special linear group of order four over real numbers. While the classical length spectrum is given as an estimate for a yes function counting prime geodesics of appropriate length, its generalized form is usually represented by a higher order counting function of Chebyshev type. Our goal is to prove that the error term that appears in the classical case in this setting can be significantly improved when derived via analogous, generalized apparatus.
In this paper, we consider the remainder in a weighted form of the length spectrum for compact Riemann surfaces of genus greater than or equal to two. Earlier, we conducted a similar research where we applied the Cauchy residue theorem over two different square boundaries, one of which intersected the corresponding critical line, and some, quite complex estimates for the logarithmic derivative of the associated zeta functions of Selberg and Ruelle. The main goal of this paper is to achieve the same length spectrum with the same remainder as in our previous study, but in a much simpler way.
In the last two decades, attention on forests and ownership rights has increased in different domains of international policy, particularly in relation to achieving the global sustainable development goals. This paper looks at the changes in forest-specific legislation applicable to regular productive forests, across 28 European countries. We compare the legal framework applicable in the mid-1990s with that applicable in 2015, using the Property Rights Index in Forestry (PRIF) to measure changes across time and space. The paper shows that forest owners in most western European countries already had high decision-making power in the mid-1990s, following deregulation trends from the 1980s; and for the next two decades, distribution of rights remained largely stable. For these countries, the content and direction of changes indicate that the main pressure on forest-focused legislation comes from environmental discourses (e.g. biodiversity and climate change policies). In contrast, former socialist countries in the mid-1990s gave lower decision-making powers to forest owners than in any of the Western Europe countries; over the next 20 years these show remarkable changes in management, exclusion and withdrawal rights. As a result of these changes, there is no longer a clear line between western and former socialist countries with respect to the national governance systems used to address private forest ownership. Nevertheless, with the exception of Baltic countries which have moved towards the western forest governance system, most of the former socialist countries still maintain a state-centred approach in private forest management. Overall, most of the changes we identified in the last two decades across Europe were recorded in the categories of management rights and exclusion rights. These changes reflect the general trend in European forest policies to expand and reinforce the landowners’ individual rights, while preserving minimal rights for other categories of forest users; and to promote the use of financial instruments when targeting policy goals related to the environmental discourse.
Abstract The subject of this research are the demographic trends and the educational system of the Republic of Srpska. The aim of the research is to define the concepts required to comprehend the demographic trends and to explore their implications for the educational system of the Republic of Srpska. In order to establish sustainable development in the Republic of Srpska, education being a key component therein, it is necessary to perceive its demographic resources in order to create an educational system. By means of empirical research with a presentation of results through factor and cluster analysis, generated quantitative and qualitative indices of demographic resources, particularly in the educational system. The Republic of Srpska as a whole belongs to type D, featuring poor demographic resources and characteristics, as well as prominent demographic disparities regarding spatial development. However, in order to increase the coverage, relevance and efficiency of completion of the education process, it is necessary to determine the strategic commitments to be accomplished together with certain quantitative demographic indicators of the achievement level (educational coverage of different generations). Demographic changes will pose a major challenge for policy makers and to the society in general across the upcoming decades and will require shaping new economic, tax, health, pension, educational, social, family and other policies that affect demographic changes. The research endeavour in this paper focuses on that very aspect, together with the respective applicative capabilities.
Summary A word, a term, written or spoken is the most beautiful jewel that a civilization can make. It can be therefore said that the specialized terminology of a particular profession – is its jewel. This professional jewel, specialized terminology, reflects not only its present time but also all the past ages it was developed through into a jewel of a culture and its civilizational value. This also applies to the specialized terminology of physical culture that is, the terminology of physical education and sport. It is also the jewel which reflects the present and the past; its developmental path that has always been adjusted to the social circumstances and time it has existed in. Its terminology can provide insight into its development, rises and falls, turns to the prevailing ’’noble’’ ideas, inflow of foreign words into the body of the specialized terminology. Development of the specialized terminology for physical culture that is, physical education and sport includes not only deep consideration and proficiency but also good intentions to make improvements to the profession and not to the current geopolitical (in)conveniences. It is therefore very important to emphasize that search and selection of a term which can indeed reflect the conceptual content in question is neither easy nor automatic. Moreover, if a good intention is missing, then various problems in communication can occur. The Latins described it very well: Nomen est omen. Doubts about terms: physical culture – sport, physical education – sport education, physical exercising – physical activity, physical recreation – sport recreation are just some of the examples indicating that it is necessary to continue the development of the multilingual specialized terminology dictionary for our profession.
Roadway free-flow speed captures the typical vehicle speed in low traffic conditions. Modeling free-flow speed is an important problem in transportation engineering with applications to a variety of design, operation, planning, and policy decisions of highway systems. Unfortunately, collecting large-scale historical traffic speed data is expensive and time consuming. Traditional approaches for estimating free-flow speed use geometric properties of the underlying road segment, such as grade, curvature, lane width, lateral clearance and access point density, but for many roads such features are unavailable. We propose a fully automated approach, RasterNet, for estimating free-flow speed without the need for explicit geometric features. RasterNet is a neural network that fuses large-scale overhead imagery and aerial LiDAR point clouds using a geospatially consistent raster structure. To support training and evaluation, we introduce a novel dataset combining free-flow speeds of road segments, overhead imagery, and LiDAR point clouds across the state of Kentucky. Our method achieves state-of-the-art results on a benchmark dataset.
Introduction: Hyperuricemia is an independent risk factor for the development of many diseases. Aim: The aim of this paper is to compare the effects of allopurinol and febuxostat on the values of triglycerides and uric acid in hyperuricemic patients. Methods: This was a pharmacological-clinical retrospective-prospective study. The research sample comprised 50 examinees of both genders and different ages who were undergoing allopurinol (100 mg/day) or febuxostat (80 mg/day) therapy. Statistical Product and Service Solutions (SPSS) Software and Microsoft Excel were used for statistical analysis. Results: Examinees who were treated with allopurinol had a statistically significant decrease in uric acid concentrations (by 126.28 ± 20.36 μmol/l) at the end of the observation compared to the initial values (p = 0.006). Examinees who were treated with febuxostat had a statistically significant decrease in uric acid concentrations (by 252.80 ± 94.17 μmol/l) at the end of the observation compared to the initial values (p = 0.001). The initial value of triglycerides was 1.58 ± 0.64 mmol/l in allopurinol-treated examinees, and 1.60 ± 0.52 mmol/l in febuxostat-treated examinees. After three and six months of allopurinol use, there was a statistically significant increase in triglyceride values (p = 0.046 and p = 0.042, respectively). A statistically significant decrease in triglyceride values (by 0.16 ± 0.10 mmol/l) was noted after three months of febuxostat use (p = 0.012). Conclusion: The results of this research confirmed the previous findings and pointed out the positive pharmacological effects of allopurinol and febuxostat.
A questionnaire on biomarker testing previously used in central European countries was extended and distributed in Western and Central European countries to the pathologists participating at the Pulmonary Pathology Society meeting 26–28 June 2019 in Dubrovnik, Croatia. Each country was represented by one responder. For recent biomarkers the availability and reimbursement of diagnoses of molecular alterations in non-small cell lung carcinoma varies widely between different, also western European, countries. Reimbursement of such assessments varies widely between unavailability and payments by the health care system or even pharmaceutical companies. The support for testing from alternative sources, such as the pharmaceutical industry, is no doubt partly compensating for the lack of public health system support, but it is not a viable or long‐term solution. Ideally, a structured access to testing and reimbursement should be the aim in order to provide patients with appropriate therapeutic options. As biomarker enabled therapies deliver a 50% better probability of outcome success, improved and unbiased reimbursement remains a major challenge for the future.
This paper investigates the influence of user dynamics on small-scale fading characteristics in off-body channels. A statistical channel model employing a mobility model for wearable antennas on dynamic users is presented. The model is used to analyze the effects of both user’s linear forward motion and periodic wearable antenna displacement due to changes in posture, for walking and running. The time-variant Doppler shift exhibited by signals arriving from different directions is considered for wearable antennas on the chest, wrist and lower leg. A strong influence of the on-body placement is observed, with antennas on the arms and legs yielding up to a 2.2 times higher maximum Doppler frequency than with the antenna on the torso. Furthermore, the small-scale fading dynamics for these antennas vary considerably during the motion cycle, where one can distinguish between slow and fast phases. The latter is found to yield up to 4 times as high root-mean-square level-crossing rates than the former, in the case of the antenna on the lower leg. These findings imply an important effect of the periodic antenna displacement on fading dynamics in off-body channels, which is typically neglected in literature.
This paper presents an off-body indoor propagation channel model. The model is based on a Friis transmission equation to which it adds the orientation-dependent body shadowing loss by adopting a basic model derived from a cosine function. Furthermore, the developed propagation model accounts for human body dynamics and different material reflections coefficients, both implemented using a random variables with uniform distribution. Created model was evaluated against a set of measurements conducted in the indoor environment at mmWave frequency (60 GHz) gathered from the literature, showing a good fit. The difference between the slopes of the proposed model and measurements is less than 6%.
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