Structure and morphology of linear polyethylene extrudates induced by elongational flow

This study focuses on the structure, morphology, and properties of linear polyethylene (PE) profiles manufactured by continuous extrusion. High level of chain orientation was achieved using specific flow and processing conditions. An extrusion die with semihyperbolic convergency was used to generate high percentage of elongational flow and chain extension. Simultaneously, high extrusion pressure and relatively low melt temperature led to flow‐induced crystallization of PE extended chains. The structure of PE tapes consists of crystal aggregates with different level of orientation and crystallinity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Assessing urban stormwater toxicity: methodology evolution from point observations to longitudinal profiling.

The quality of aquatic habitat in a stormwater management facility located in Toronto, Ontario, was assessed by examining ecotoxicological responses of benthic invertebrates exposed to sediment and water from this system. Besides residential stormwater, the facility receives highway runoff contaminated with trace metals, polycyclic aromatic hydrocarbons (PAHs), and road salt. The combined flow passes through two extended detention ponds (in series) and a vegetated outlet channel. Toxicity of surficial sediment collected from 14 longitudinally arrayed locations was assessed based on 10 acute and chronic endpoints from laboratory tests with four benthic organisms. Greatest overall toxicity was observed in sediment from sites in the upstream pond, where mortality to amphipods and mayflies reached up to 100%. Downstream pond sediment was less toxic on average than the upstream pond sediment, but not the outlet channel sediment where untreated stormwater discharges provided additional sources of contamination. Macroinvertebrate communities in sediment cores were depauperate and dominated by oligochaetes and chironomids, with minimum densities and diversity at the deeper central pond sites. While sediment toxicity was associated with high concentrations of trace metals and high-molecular weight PAHs, benthic community impoverishment appeared related to high water column salinity.     

Scintillation properties of Pr3+-doped lutetium and yttrium aluminum garnets: Comparison with Ce3+-doped ones

Scintillation properties of Pr³⁺-doped LuAG and YAG crystals were investigated and compared with those of Ce³⁺-doped ones. The highest L.Y.’s were observed with the longest shaping time 10 μs. They can reach up to ～16,000 ph/MeV or ～23,500 ph/MeV for LuAG:Pr and LuAG:Ce, respectively. Energy resolutions (FWHM) are a bit better with LuAG:Pr than those of LuAG:Ce, e.g. at 662 keV FWHM are around 6% and between 8–12%, respectively. There were observed no large changes in proportionality of Pr³⁺- or Ce³⁺-doped LuAG or YAG crystals but the best proportionality has YAP:Ce crystal. Pr³⁺- or Ce³⁺-doped LuAG crystals exhibit slow decay components in the time range 1.5–3.5 μs while those of YAG ones have shorter decay components between 0.3–1.7 μs.     

A cold model analysis of solid waste incineration

A cold physical model to a scale of 1:33 of a solid waste incinerator was designed and constructed of transparent material. Experimentation aimed at optimizing gas flow patterns in the furnace for low-pollutant combustion. Flames were simulated by acid-base neutralization. Secondary air flow distribution and direction were identified as the controlling parameters of the flow pattern. The best possible air distribution for a desired flame shape and gas mixing was determined. Streamline plots for verification of the mathematical models were obtained.     

Application of random-search algorithm for regression analysis of catalytic hydrogenations

A short review of the works concerning parameter estimation in kinetic experiments was performed. An adaptive random search algorithm was applied to evaluate the parameters and parameter confidence intervals of Langmuir-Hinshelwood models. The kinetic parameters were determined using the Box - Draper criterion. The parameter confidence regions were found by using the likelihood ratio. Three heterogeneously catalyzed hydrogenations were studied.     

Indene epoxidation over immobilized methyltrioxorhenium on MCM-41 silica,fumed silica and aluminosilicate materials

The presented report focuses on the testing of heterogenized methyltrioxorhenium (MTO) in indene epoxidation. A range of mesoporous materials with different SiO₂/Al₂O₃ ratios, namely aluminosilicates type Siral and MCM-41 silica and fumed silica, were used as supports for immobilization of MTO. The tested support materials and prepared catalytic systems exhibited high surface area, well-defined regular structure and narrow pore size distribution of mesopores and therefore represent good quality catalysts for various reactions. The immobilized MTO on various supports was tested for the preparation of 1,2-epoxyindane using two forms of hydrogen peroxide as oxidation agents, namely aqueous solution of hydrogen peroxide and its anhydrous form, urea-hydrogen peroxide. The prepared catalysts were successfully used for the preparation of 1,2-epoxyindane with achieved 100 % selectivities to the desired product at high conversions of indene.     

3GPP LTE‐Assisted Wi‐Fi‐Direct: Trial Implementation of Live D2D Technology

This paper is a first‐hand summary on our comprehensive live trial of cellular‐assisted device‐to‐device (D2D) communications currently being ratified by the standards community for next‐generation mobile broadband networks. In our test implementation, we employ a full‐featured 3GPP LTE network deployment and augment it with all necessary support to provide real‐time D2D connectivity over emerging Wi‐Fi‐Direct (WFD) technology. As a result, our LTE‐assisted WFD D2D system enjoys the required flexibility while meeting the existing standards in every feasible detail. Further, this paper provides an account on the extensive measurement campaign conducted with our implementation. The resulting real‐world measurements from this campaign quantify the numerical effects of D2D functionality on the resultant system performance. Consequently, they shed light on the general applicability of LTE‐assisted WFD solutions and associated operational ranges.     

Natriuretic peptides increase a K+ conductance in rat mesangial cells

Mesangial cells (MC) are a main target of natriuretic peptides in the kidney and are thought to play a role in regulating glomerular filtration rate. We examined the influence of cGMP-generating (i.e. guanosine 3',5'-cyclicmonophosphate) peptides on membrane voltages (Vm) of rat MC by using the fast whole-cell patch-clamp technique. The cGMP-generating peptides were tested at maximal concentrations ranging from 140 to 300 nmol/l. Whereas human CNP (C natriuretic peptide), rat guanylin and human uroguanylin had no significant effect on Vm these cells, human BNP (brain natriuretic peptide), rat CDD/ANP-99-126 (cardiodilatin/atrial natriuretic peptide) and rat CDD/ANP-95-126 (urodalatin) hyperpolarized Vm significantly by 1.6 +/- 0.4 mV (BNP, n=8), 3.7 +/- 0.3 mV (CDD/ANP-99-126, n=25) and 2.8 +/- 0.4 mV (urodilatin, n=9), respectively. The half-maximally effective concentration (EC50) for the latter two was around 400 pmol/l each. This hyperpolarization could be mimicked with 0.5 mmol/l 8-bromo-guanosine 3',5'-cyclic monophosphate (8-Br-cGMP) and was blocked by 5 mmol/l Ba2+. The K+ channel blocker 293 B (100 micromol/l) depolarized basal Vm by 4.3 +/- 0.4 mV (n=8), but failed to inhibit the hyperpolarization induced by CDD/ANP-99-126 (160 nmol/l) (n=8). The K+ channel opener cromakalim (10 micromol/l) neither influenced basal Vm nor altered the hyperpolarization induced by 160 nmol/l CDD/ANP-99-126 (n=8). Adenosine (100 micromol/l) hyperpolarized Vm by 13.4 +/- 1.3 mV (n=16). At 100 micromol/l, 293 B did not inhibit the adenosine-induced hyperpolarization (n=6). At 160 nmol/l, CDD/ANP-99-126 enhanced the adenosine-induced hyperpolarization significantly by 1.5 +/- 0.6 mV (n=10). CDD/ANP-99-126 (160 nmol/l) failed to modulate the value to which Vm depolarized in the presence of 1 nmol/l angiotensin II (n=10), but accelerated the repolarization to basal Vm by 49 +/- 20% (n=8). These results indicate that the natriuretic peptides CDD/ANP-99-126, CDD/ANP-95-126 and BNP hyperpolarize rat MC probably due to an increase of a K+ conductance. This effect modulates the voltage response induced by angiotensin II. The natriuretic-peptide-activated conductance can be blocked by Ba2+, but not by 293 B and cannot be activated by cromakalim. This increase in the K+ conductance seems to be additive to that inducable by adenosine, indicating that different K+ channels are activated by these hormones.     

Bestimmung des Grenzumformgrades mit dem Torsionsversuch

Die Bestimmung des Grenzumformgrades eines Stahles, der während der plastischen Verformung nicht überschritten werden kann, ist von großer Bedeutung. Die vorliegende Arbeit berichtet über Ergebnisse von Warmtorsionsversuchen, aus denen der Grenzumformgrad als Funktion von Temperatur und Umformgeschwindigkeit ermittelt wurde. Die Versuche wurden an den Stählen X 10 CrNiTi 18 9, 10 CrMo 9 10, X 10 CrNiMoTi 18 12, X 20 CrMoV 12 1 und X 2 NiCrNb 25 18 durchgeführt.