Total and extractable element concentrations in bed sand material from a medium-sized (32 MW) municipal district heating plant incinerating peat, stumps, sawdust and recycled wood

In Finland, the new limit values of total heavy metal, polychlorinated biphenyl (PCB) and polycyclic aromatic hydrocarbon (PAH), as well as the extractable heavy metal, dissolved organic carbon (DOC), fluoride, sulphate, and chloride concentrations for bed sand material used as an earth construction agent came into force in June 2009. The total heavy metal (i.e. Cd, Cu, Pb, Cr, Zn, As, V, Ba and Mo) concentrations in the studied bed sand material were clearly lower than the current Finnish limit values for the maximum allowable heavy metal concentrations for materials used as an earth construction agent. However, the extractable concentration of Ba (24.6 mg kg⁻¹; d.w.) in the bed sand material exceeded the limit value for covered structures (20 mg kg⁻¹; d.w.). However, in Finland, the competent environmental authority may relax the maximum limit values up to 30% in certain circumstances. Therefore, if, the environmental authority relaxes the maximum limit value for the extractable concentration of Ba by up to 30% to the value of 26 mg kg⁻¹ (d.w.) for covered structures, the extractable concentration of Ba (24.6 mg kg⁻¹; d.w.) in the bed sand material is below this relaxation.     

Deuterium kinetic isotopic study for hydrogenolysis of ethyl butyrate

The hydrogenation of ethyl butyrate, n-butyric acid, and n-butyraldehyde to their corresponding alcohol(s) has been studied over a γ-Al₂O₃-supported cobalt catalyst using a high-pressure fixed-bed reactor in the temperature range of 473–493 K. H₂–D₂–H₂ switching experiments show that ethyl butyrate and n-butyric acid follow an inverse kinetic isotope effect (KIE) (i.e. r^H/r^D = 0.50–0.54), whereas n-butyraldehyde did not display any KIE (i.e. r^H/r^D = 0.98). DRIFTS experiments were performed over the support and catalyst to monitor the surface species formed during the adsorption of ethyl butyrate and n-butyric acid at atmospheric pressure and the desired temperature. Butanoate and butanoyl species are the stable surface intermediates formed during hydrogenation of ethyl butyrate. Hydrogenation of butanoate to a partially hydrogenated intermediate is likely involved in the rate-determining step of ethyl butyrate and butyric acid hydrogenation.     

Sequential Change-Point Detection Procedures That are Nearly Optimal and Computationally Simple

Abstract

Sequential schemes for detecting a change in distribution often require that all of the observations be stored in memory. Lai (1995 Lai , T. L. ( 1995 ). Sequential Changepoint Detection in Quality Control and Dynamical Systems , Journal of Royal Statistical Society, Series B 57 : 613 – 658 . [Google Scholar], Journal of Royal Statistical Society, Series B 57: 613–658) proposed a class of detection schemes that enable one to retain a finite window of the most recent observations, yet promise first-order optimality. The asymptotics are such that the window size is asymptotically unbounded. We argue that what's of computational importance isn't having a finite window of observations, but rather making do with a finite number of registers. We illustrate in the context of detecting a change in the parameter of an exponential family that one can achieve eventually even second-order asymptotic optimality through using only three registers for storing information of the past. We propose a very simple procedure, and show by simulation that it is highly efficient for typical applications.     

Friction and Wear of Low-Phosphorus Engine Oils with Additional Molybdenum and Boron Compounds,Measured on a Reciprocating Lubricant Tester

Previous research has already extensively characterized the effects of a variety of engine oils on engine performance. However, low-phosphorus engine oils, which are of growing importance due to the reduction of automotive emissions, have not been studied much. This paper sets forth the results of an initial investigation involving the effects of low-phosphorus engine oils on the friction and wear characteristics of typical engine cylinder kit components from a 3.8-liter, four-cylinder engine. For these tests, sections of molybdenum-coated piston rings were oscillated against segments of production cast iron cylinder bores. The oils were evaluated under two sets of conditions; i.e., the frequency of 20 Hz and a load of 60 N and a frequency of 40 Hz and a load of 120 N. The friction coefficients were continuously recorded, and the wear depths on the cylinder bore segments were measured at the conclusion of each experiment. The oils consisted of low-phosphorus prototype oil (LPPO) containing 0.05 wt% phosphorus, which is half the amount of ZDDP in GF–3 oils, and the LPPO treated with six different supplemental antiwear, anti-friction additives. The remaining additives in the LPPO were present in the amount required for full GF–3 formulation. The supplemental additives were selected to lower friction and replace and/or enhance antioxidant and antiwear properties lost due to lower zinc dithiophosphate (ZDDP) content. The results of low phosphorus concentration oils were compared to the results obtained with formulated ILSAC GF-3 engine oil. The oils that contained organomolybdenum ester showed the greatest benefit in friction reduction in the two different operating conditions. SEM/EDS/XPS surface analyses on the surfaces run with oils containing organomolybdenum ester showed evidence of molybdenum compound formation on the cylinder bore surface. In addition, antiwear film formation mechanisms due to surface interaction among the ZnDTP, organomolybdenum compounds, and metal oxides are discussed.     

Finding little Albert: A journey to John B. Watson’s infant laboratory.

In 1920, John Watson and Rosalie Rayner claimed to have conditioned a baby boy, Albert, to fear a laboratory rat. In subsequent tests, they reported that the child’s fear generalized to other furry objects. After the last testing session, Albert disappeared, creating one of the greatest mysteries in the history of psychology. This article summarizes the authors’ efforts to determine Albert’s identity and fate. Examinations of Watson’s personal correspondence, scientific production (books, journal articles, film), and public documents (national census data, state birth and death records) suggested that an employee at the Harriet Lane Home was Albert’s mother. Contact with the woman’s descendents led the authors to the individual they believe to be “Little Albert.” (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functionalization of electrospun fibers of poly(ε-caprolactone) with star shaped NCO-poly(ethylene glycol)-<Emphasis Type="Italic">stat</Emphasis>-poly(propylene glycol) for neuronal cell guidance

Microfibers produced with electrospinning have recently been used in tissue engineering. In the development of artificial implants for nerve regeneration they are of particular interest as guidance structures for cell migration and axonal growth. Using electrospinning we produced parallel-orientated biocompatible fibers in the submicron range consisting of poly(ε-caprolactone) (PCL) and star shaped NCO-poly(ethylene glycol)-stat-poly(propylene glycol) (sPEG). Addition of the bioactive peptide sequence glycine-arginine-glycine-aspartate-serine (GRGDS) or the extracellular matrix protein fibronectin to the electrospinning solution resulted in functionalized fibers. Surface characteristics and biological properties of functionalized and non-functionalised fibers were investigated. Polymer solutions and electrospinning process parameters were varied to obtain high quality orientated fibers. A polymer mixture containing high molecular weight PCL, PCL-diol, and sPEG permitted a chemical reaction between hydroxyl groups of the diol and isocyanante groups of the sPEG. Surface analysis demonstrated that sPEG at the fiber surface minimized protein adhesion. In vitro experiments using dorsal root ganglia explants showed that the cell repellent property of pure PCL/sPEG fibers was overcome by functionalization either with GRGDS peptide or fibronectin. In this way cell migration and axonal outgrowth along fibers were significantly increased. Thus, functionalized electrospun PCL/sPEG fibers, while preventing non-specific protein adsorption, are a suitable substrate for biological and medical applications.     

An analytical solution for transient flow of Bingham viscoplastic materials in rock fractures

We present below an analytical solution to model the one-dimensional transient flow of a Bingham viscoplastic material in a fracture with parallel walls (smooth or rough) that is subjected to an applied pressure gradient. The solution models the acceleration and the deceleration of the material as the pressure gradient changes with time. Two cases are considered: a pressure gradient applied over a finite time interval and an applied pressure gradient that is constant over time. The solution is expressed in dimensionless form and can therefore be used for a wide range of Bingham viscoplastic materials. The solution is also capable of capturing the transition that takes place in a fracture between viscoplastic flow and rigid plug flow. Also, it shows the development of a rigid central layer in fractures, the extent of which depends on the fluid properties (viscosity and yield stress), the magnitude of the pressure gradient, and the fracture aperture and surface roughness. Finally, it is shown that when a pressure gradient is applied and kept constant, the solution for the fracture flow rate converges over time to a steady-state solution that can be defined as a modified cubic law. In this case, the fracture transmissivity is found to be a non-linear function of the head gradient. This solution provides a tool for a better understanding of the flow of Bingham materials in rock fractures, interfaces, and cracks.     

Network support for IP traceback

This paper describes a technique for tracing anonymous packet flooding attacks in the Internet back toward their source. This work is motivated by the increased frequency and sophistication of denial-of-service attacks and by the difficulty in tracing packets with incorrect, or “spoofed,” source addresses. We describe a general purpose traceback mechanism based on probabilistic packet marking in the network. Our approach allows a victim to identify the network path(s) traversed by attack traffic without requiring interactive operational support from Internet service providers (ISPs). Moreover, this traceback can be performed “post mortem”-after an attack has completed. We present an implementation of this technology that is incrementally deployable, (mostly) backward compatible, and can be efficiently implemented using conventional technology