Rate of Convergence to Barenblatt Profiles for the Fast Diffusion Equation

We study the asymptotic behaviour of positive solutions of the Cauchy problem for the fast diffusion equation near the extinction time. We find a continuum of rates of convergence to a self-similar profile. These rates depend explicitly on the spatial decay rates of initial data

ІНФОРМАЦІЙНІ ТЕХНОЛОГІЇ ПРОСТОРОВОЇ ІНВЕНТАРИЗАЦІЇ ПАРНИКОВИХ ГАЗІВ У ЕНЕРГЕТИЧНОМУ СЕКТОРІ СІЛЕЗЬКОГО ВОЄВОДСТВА

GIS technology of spatial inventory of greenhouse gases (carbon dioxide, methane, etc.) in the energy sector of Silesia Region in Poland has been presented. Georeferenced databases, GIS software, and international inventory methodologies have been used. The mathematical models for inventory of carbon dioxide, methane and other greenhouse gases during the combustion of fuel in the production of electricity, in the residential sector, industry, construction, and transport have beencreated. These models allow to obtain the spatial distribution of total emissions of greenhouse gases of Silesia Region, taking into account the contribution of each region in the overall processes of emission.Представлено геоінформаційні технології просторової інвентаризації парникових газів (двоокису вуглецю, метану та ін.) в енергетичному секторі в Сілезькому воєводстві Польщі. Використано георозподілені бази даних, програмне забезпечення геоінформаційної системи та міжнародні методології інвентаризації. Розроблено математичні моделі для інвентаризації двоокису вуглецю, метану та інших парникових газів в процесі спалювання палива на виробництво електроенергії, в житловому секторі, у промисловості та будівництві, на транспорті. Ці моделі дали змогу отримати просторовий розподіл сумарних викидів парникових газів Сілезького воєводства з врахуванням внеску кожного району в загальні процеси емісії

Numerical approximation of a concrete carbonation model: study of the t\sqrt{t}-law of propagation

International audienceIn this paper, we are interested in the long time behavior of approximate solutions to a free boundary model which appears in the modeling of concrete carbonation [1]. In particular, we study the long time regime of the moving interface. The numerical solutions are obtained by an implicit in time and finite volume in space scheme. We show the existence of solutions to the scheme and, following [2, 3], we prove that the approximate free boundary increases in time following a $\sqrt{t}$-law. Finally, we supplement the study through numerical experiments

Improvement of local Resistance of Safety-Related Structures and Reduction of Dynamic Response due to Missile Impact Loading

Evaluation of the load-bearing and shielding capacity of safety-related structures not designed for missile impact loading (e.g. from aircraft crash) led to problem-specific investigations, conducted with the aim of establishing effective shielding, reinforcing and energy dissipation concepts. To ensure protection of structures against missile impact, emphasis was placed in this study not only on upgrading the penetration resistance of the structures in the impacted area, but also in particular on reducing the dynamic response induced by impact loads. Although a number of shielding concepts exist which are useful in a theoretical sense, only a few of these are of any practical significance due to the rather small region affected by impact loading and the rather high magnitude of the loads. Any shielding concept suitable for protecting a building against the impact of a missile (e.g. aircraft) over its entire outer surface must provide the target with homogeneous protection in the form of a jacket of high strength and high energy dissipation capacity. Of the various concepts investigated, the most promising seems to be that providing protection by means of hollow-wall designs or special shielding elements, both made of energy-absorbing high-quality steel-fiberreinforced concrete [1]. This paper covers studies of different local design concepts for the targeted regions and material parameters which have a strong influence on the penetration resistance as well as energy dissipation capabilities of the impacted building. Possibilities for reinforcing the outer shells of typical buildings not originally designed to withstand missile impact are also presented

Enhancement of CO2/CH4 separation performances of 6FDA-based co-polyimides mixed matrix membranes embedded with UiO-66 nanoparticles

Metal-organic frameworks (MOFs) incorporation into mixed matrix membranes (MMMs) is gaining more attention due to the combined advantages of high separation performance and easy processability. Nanoparticles (NPs) of CO2-philic MOF UiO-66 (Zr-BDC) were synthesized with high surface area and ca. 50 nm particle size (and also for comparison with 100 and 200 nm sizes). They were incorporated into three 6FDA-based co-polyimides (namely 6FDA-BisP, 6FDA-ODA, and 6FDA-DAM), forming MMMs with loadings in the 4–23 wt% range. The NPs and MMMs were characterized accordingly by XRD, BET, SEM, TEM, FTIR, and TGA. CO2 and CH4 isotherms on the NPs were measured by a static volumetric method at the pressure up to 10 bar. Fractional free volume (FFV) was calculated using solid density, measured by pycnometer. Gas separation performance was evaluated using a feed composition of 50%:50% CO2:CH4 binary mixture at 35 °C and a pressure difference of 2 bar. The presence of UiO-66 NPs in the continuous 6FDA-BisP and 6FDA-ODA co-polyimides improved both CO2 permeability and CO2/CH4 selectivity by 50–180% and 70–220%, respectively. In the case of 6FDA-DAM MMMs, the CO2 permeability was significantly improved by 92%, while maintaining the CO2/CH4 selectivity. The best results in terms of CO2/CH4 selectivity were 41.9 for 6FDA-BisP (17 wt% filler loading, 108 Barrer of CO2), 57.0 for 6FDA-ODA (7 wt% filler loading, 43.3 Barrer of CO2) and 32.0 for 6FDA-DAM (8 wt% filler loading, 1728 Barrer of CO2)

Quality assessment of vascular access procedures for hemodialysis: A position paper of the Vascular Access Society based on the analysis of existing guidelines

Quality assessment in vascular access procedures for hemodialysis is not clearly defined. The aim of this article is to compare various guidelines regarding recommendation on quality control in angioaccess surgery. The overall population of end-stage renal disease patients and patients in need for hemodialysis treatment is growing every year. Chronic intermittent hemodialysis is still the main therapy. The formation of a functional angioaccess is the cornerstone in the management of those patients. Native (autologous) arteriovenous fistula is the best vascular access available. A relatively high percentage of primary failure and fistula abandonment increases the need for quality control in this field of surgery. There are very few recommendations of quality assessment on creation of a vascular access for hemodialysis in the searched guidelines. Some guidelines recommend the proportion of native arteriovenous fistula in incident and prevalent patients as well as the maximum tolerable percentage of central venous catheters and complications. According to some guidelines, surgeon's experience and expertise have a considerable influence on outcomes. There are no specific recommendations regarding surgeon's specialty, grade, level of skills, and experience. In conclusion, there is a weak recommendation in the guidelines on quality control in vascular access surgery. Quality assessment criteria should be defined in this field of surgery. According to these criteria, patients and nephrologists could choose the best vascular access center or surgeon. Centers with best results should be referral centers, and centers with poorer results should implement quality improvement programs

Expression and Function of Neurotrophins and Their Receptors in Cultured Human Keratinocytes

Whereas nerve growth factor has been extensively studied in human keratinocytes, little is known on the role of other members of the neurotrophin family. We investigated the expression and function of neurotrophins and neurotrophin receptors in cultured human keratinocytes. We demonstrated by reverse transcription–polymerase chain reaction that keratinocytes synthesize neurotrophin-3, brain-derived neurotrophic factor, and neurotrophin-4/5. These cells also express tyrosinase kinase A and C, the nerve growth factor and neuro-trophin-3 high-affinity receptors, respectively. On the other hand, only the truncated extracellular isoform of tyrosinase kinase B, the high-affinity brain-derived neurotrophic factor and neurotrophin-4/5 receptor, is detected in keratinocytes. Moreover, neurotrophin-3, brain-derived neurotrophic factor, and neurotrophin-4/5 proteins are secreted by human keratinocytes at low levels. Keratinocyte stem cells synthesize the highest amounts of nerve growth factor, while they secrete higher levels of nerve growth factor as compared with transit amplifying cells. Neurotrophin-3 stimulates keratinocyte proliferation, where brain-derived neurotrophic factor or neurotrophin-4/5 does not exert any effect on keratinocyte proliferation. Addition of neurotrophin-3 slightly upregulates the secretion of nerve growth factor, whereas nerve growth factor strongly augments neurotrophin-3 release. Ultraviolet B irradiation downregulates nerve growth factor, whereas it augments neurotrophin-3 and neurotrophin-4/5 protein levels. Ultraviolet A irradiation increases the level of neurotrophin-3, whereas it does not exert any effect on the other neurotrophins. Finally, neurotrophins other than nerve growth factor fail to protect human keratinocytes from ultraviolet B-induced apoptosis. This work delineates a functional neurotrophin network, which may contribute to epidermal homeostasis