Measurement and comparison of energy of mechanical vibrations absorbed by humans

Human body responds to mechanical vibrations differently. Vibrations cause various types of damage to human organism. There are two main types of effects: short-term and longterm ones. The former cause tiredness, drowsiness and focus loss. While the latter induce mechanical damage to the individual organs such as skeleton, joints, nervous system. Influence of mechanical vibrations on human body is assessed by different parameters including amplitude, frequency, duration of action, acceleration etc. The next evaluation parameter might be energy. This article reports on the laboratory measurements of absorption of mechanical vibrations by humans. From our perspective, the short-time damage to human is mainly caused by absorption of vibrational energy and long-term damage - by mechanical vibration itself. A bio-dynamic system represents human body located in an automobile seat. The source of vibrations simulates car body movements generated during driving. The energy is measured in several levels because of the description of energy flow system. The primary aim is to determinate the level of the vibrational energy that enters into a human body and is subsequently absorbed. This is considered in terms of level and spectrum of input mechanical vibrations. Based on the findings, it is possible to evaluate the level of absorbed energy and compare for the sample of population

Extracellular Matrix Proteins and Tumor Angiogenesis

Tumor development is a complex process that relies on interaction and communication between a number of cellular compartments. Much of the mass of a solid tumor is comprised of the stroma which is richly invested with extracellular matrix. Within this matrix are a host of matricellular proteins that regulate the expression and function of a myriad of proteins that regulate tumorigenic processes. One of the processes that is vital to tumor growth and progression is angiogenesis, or the formation of new blood vessels from preexisting vasculature. Within the extracellular matrix are structural proteins, a host of proteases, and resident pro- and antiangiogenic factors that control tumor angiogenesis in a tightly regulated fashion. This paper discusses the role that the extracellular matrix and ECM proteins play in the regulation of tumor angiogenesis

A Reflection on Growth Mindset and Meritocracy

As mathematicians working in higher education we reflect on meritocracy and growth mindset with a focus on the relationship between the two. We also note the subtle differences between growth mindset and grit. Our reflection ends with suggestions for how to move forward in the math classroom and throughout the collegiate level

Economic evaluation of investment project in the area of sheet metal processing

The article is oriented on the process modelling in selected company. The aim of the process modelling is a possibility to prevent the formation of future risks as a consequence of a wrong decision concerning a capital project. The analysis of actual state in society with the focus on the means of processing the lamination using computer numeric control technology is also a part of article. Based on the analysis mentioned above, the selection and the definition of the capital project have already been carried out. Final section evaluates the capital project using methodology of economic indicators by means of economic indicators of effectiveness and brings a decision whether to accept or refuse given investment

Chemical Partitioning and Mobility of Trace Elements in Dry Disposed Weathered Ash Conditioned with High-Saline Effluents

Weinvestigated the mobility of inorganic elements in the ash dump due to chemical interaction of weathered dry disposed ash conditioned with high-saline effluents and ingressed CO2 from atmosphere and percolating rainwater. Drilled ash core samples collected from dry disposed ash dump at a South African coal-burning power station were characterized using X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses. A modified sequential extraction procedure was selected to determine the mineralogical association of the investigated elements in the 1-year-old drilled ash cores. Major mineral phases are quartz and mullite and other minor phases included hematite, lime, calcite, anorthite, mica, and enstatite. Mica and calcite in the ash cores is attributed to carbonation process, which led to long-term reduction in pore water pH. The 2-week-old ash cores are sialic but the 1-year-old ash cores were both sialic and ferrocalsialic in chemical composition. The ferrocalsialic nature of 1-year-old ash cores could be attributed to drastic changes in feed coal in the power station. The chemical index of alteration (CIA) and chemical index of weathering (CIW) values suggest a relatively high degree of weathering. The changes in CIA and CIW values in the ash cores depend on the pore water pH, leaching rate, carbonation process, and possibly the conversion of the alkali and alkali earth metals into carbonates. Multivariate analysis results suggest that the major oxides and carbon percent show differences and have a greater contribution to the differentiation in the 1-year-old ash cores. Trace elements such as Mo, Cr, and Se show high mobility but As, B, and Pb exhibit fairly low mobility in the water-soluble fraction. Aconsiderable mobility of trace elements in the exchangeable and carbonate fractions is attributed to the alkaline nature and pore water pH. A decreasing response of As, Mo, Cr, and Pb in the reducible fraction with depth suggests immobility attributed to coprecipitation with the Fe- and Mn-oxide phases. On the contrary, the increasing response of Pb, Mo, and B in the carbonate fraction with depth implies mobility due to dissolution and flushing of soluble major chemical phases, as evident in the pore water pH. A considerable amount of B and Pb are concentrated in the residual fraction of 1-year-old ash cores. This suggests that, under natural settings, these elements will not be released in solution over a long time; therefore, they are not considered to be an environmental risk

Shot-noise-limited spin measurements in a pulsed molecular beam

Heavy diatomic molecules have been identified as good candidates for use in electron electric dipole moment (eEDM) searches. Suitable molecular species can be produced in pulsed beams, but with a total flux and/or temporal evolution that varies significantly from pulse to pulse. These variations can degrade the experimental sensitivity to changes in spin precession phase of an electri- cally polarized state, which is the observable of interest for an eEDM measurement. We present two methods for measurement of the phase that provide immunity to beam temporal variations, and make it possible to reach shot-noise-limited sensitivity. Each method employs rapid projection of the spin state onto both components of an orthonormal basis. We demonstrate both methods using the eEDM-sensitive H state of thorium monoxide (ThO), and use one of them to measure the magnetic moment of this state with increased accuracy relative to previous determinations.Comment: 12 pages, 6 figure

A Geochemical Analytical Scheme for the Appraisal of Partitioning and Mobility of Major elements in Weathered Dry Disposed Coal Fly Ash

South Africa is endowed with significant deposits of coal which is utilized in electricity generation to meet the nation’s energy demand. A large volume of waste solid residue from the combustion of pulverized feed coal in power stations is dry disposed in stock piles or dumps. Chemical interactions of dry disposed fly ash with ingressed CO2 from the atmosphere and infiltrating rain water would cause dissolution of the soluble components in the fly ash matrix. Chemical partitioning and mobility of major elements in samples from cores drilled into serially stacked weathered dry disposed fly ash were investigated using a modified five steps sequential extraction scheme. A total acid digestion was carried out on the original ash core samples prior to extraction to validate the extraction procedure. The geochemical distribution of the investigated major elements in 59 drilled core samples was determined by x-ray fluorescence and inductively coupled plasma mass spectrometry. The relationship between SiO2 and chemical index of alteration (CIA) showed 8 year and 20-year-old core samples have a moderate to high degree of weathering. Conversely, 1-year-old cores samples showed characteristics between low and moderate-high degrees of weathering. A cluster and discriminant analysis of the major elements was also able to reveal the subtle chemical alteration differences of the core samples. Functional analysis revealed the disparities in the dissolution patterns of major soluble components in the matrix of the drilled core samples. Modified sequential extractions revealed high concentration of the major species in the leachates for every mineralogical fraction; although the bulk of the major elements are locked up in the insoluble phase of the core samples (i.e. residual fraction) which would not be released under normal environmental conditions. It is noteworthy that the concentration of major elements in the labile fractions (water soluble + exchangeable + carbonate) was high and this has implications for the long-term durability of residual mineral phases. Relative enrichment and depletion trends of major elements are promoted by heterogeneity in the ash dump (i.e. moisture content), gradual reduction of pore water pH and continuous brine and water irrigation.Key words: Coal fly ash; Weathering; Sequential extraction scheme; Cluster analysis; Factor Analysis