Influence of the surface chemistry of modified activated carbon on its electrochemical behaviour in the presence of lead(II) ions

Cyclic voltammetric studies of the influence of surface chemistry on the electrochemical behaviour of granulated and powdered activated carbon samples in the presence of lead(II) ions both in bulk solution and pre-adsorbed on carbon were carried out. Variety in surface chemical character was achieved through modification of carbon samples by heat treatment in vacuum, ammonia and ammonia-oxygen atmospheres, as well as by oxidation in moist air and with concentrated nitric acid. For the samples obtained, the surface area (BET), acid–base neutralization capacities and sorption capacity towards Pb²⁺ ions were estimated. The states of the deposited Pb species were assessed by means of FTIR and XPS spectra as well as cyclic voltammetry. The importance of the surface chemistry of the carbon electrode materials are discussed in terms of their electrochemical properties and the mechanism of adsorption processes. The Cπ-metal and heteroatom-metal interaction are dominant in amphoteric and basic carbons, but in oxidized samples adsorption take place mainly by ion-exchange. Other forms of adsorption, such as the formation metal hydroxide species, are also covered buy this paper. Various forms of adsorbed lead species exhibit different electrochemical activities.     

Photostability of Sodium Iron Ethylenediaminetetraacetic Acid (NaFeEDTA) in Stored Fish Sauce and Soy Sauce

ABSTRACT: Sodium iron ethylenediaminetetraacetic acid (NaFeEDTA) has been suggested as a fortification compound for fish sauce and soy sauce. Its susceptibility to photodegradation in aqueous solutions however is a potential disadvantage. We determined the photostability of NaFeEDTA in fish and soy sauce stored under well-defined conditions. No degradation of NaFeEDTA was observed during storage of fortified soy sauce. Losses of up to 35% NaFeEDTA, however, occurred within 2 to 6 wk in fortified fish sauce stored in clear bottles exposed to direct sunlight. Losses were prevented by storage in amber bottles or by storing the clear bottles under indirect sunlight or in the dark.     

High-gain 1310 nm semiconductor optical amplifier modules with a built-in amplified signal monitor for optical gain control

A compact high-gain 1310-nm semiconductor optical amplifier (SOA) module incorporating two photodiodes to detect radiation emitted from the two opposite facets of the amplifier chip is reported. By subtracting their signals, a measure of the amplified signal is obtained without the need for optical filtering, Using this, amplified signals can be stabilized within 0.5 dB over a 25-dB range of input signals.     

Time restriction and the linkage between subcomponent efficiency and algebraic inequality success.

The compensatory-encoding theory (C-ET) of reading specifies how the efficiency of performance subcomponents affects comprehension under diverse task conditions. It maintains that readers can overcome weak skills through compensatory processes. To test whether C-ET captures more general principles underlying scholastic performance, the authors applied the theory to algebra: 140 undergraduates were asked to resolve algebraic inequalities under time pressure or under no time pressure. Participants were also assessed on the efficiency of the subcomponents required to execute the criterion algebraic inequality task (e.g., number identification, computation latency). Strong linkages were observed between subcomponent efficiency and algebraic inequality accuracy under time pressure, whereas weaker linkages were observed under no time pressure. Under no time pressure, rate of performance was unrelated to accuracy, all consistent with C-ET. Educational implications for helping struggling math problem solvers and for understanding standardized test results are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of the interplay between automatic processes and cognitive resources in reading.

An account was tested of the development of the interplay between automatic processes and cognitive resources in reading. According to compensatory-encoding theory, with advancing skill, readers increasingly keep automatic processes from faltering and provide timely, accurate data to working memory by pausing, looking back, rereading, and compensating in other ways when automatic processes fail. Reading skill profiles (e.g., word naming, semantic access, working memory capacity) were obtained from 71 third graders, 68 fifth graders, and 72 seventh graders from a university lab school or a public school (ages 7 to 15; 146 Caucasians, 61 African Americans, 2 Native Americans, 2 Latino Americans). Children participated in an unrestricted reading task (no time or performance pressure) and were randomly assigned to 1 of 2 levels of 3 experimental manipulations of restriction on reading: time pressure or no pressure, constant reading rate or variable reading rate, read silently or read aloud. Regression analyses revealed that developmental level and restriction moderated the reading skill level-comprehension relationship, and restriction lowered comprehension when it overwhelmed skills, especially for younger readers. Verbally inefficient readers compensated most often, and older readers compensated most efficiently. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Are general resource notions still viable in reading research?

Conducted 2 experiments to explore the interplay between reading subcomponent efficiency and comprehension processes in terms of resource competition. In Exp 1, adults were tested on the efficiency of lexical access, semantic memory access, verbal working memory span, contextual priming, and the efficiency with which anaphors are resolved. The profile was used to predict the efficiency of high-level inference generation when readers control the pace of reading. In Exp 2, this profile was used to predict the efficiency of high-level inferencing as text was presented at a preset rate. The data suggest that when readers control reading rate, they compensate for subcomponent inefficiency such that high-level comprehension is unrelated to this inefficiency. However, when they must follow along, those who possess more efficient reading subcomponents make high-level inferences more efficiently. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prescribing behaviours

This paper argues that prescribing a behaviour is different from programming a process, and presents a possible formalism for the former together with some examples.     

Relationship between residual stress and strength of single lap joints made of Ti6Al4V alloy,adhesively bonded and treated using pneumatic ball peening

The possibility of improving the strength of single lap joints (SLJs) made of Ti6Al4V alloys and adhesively bonded using Araldite 2014-1 with the help of pneumatic ball peening was investigated. The effects of pneumatic ball peening conditions on the joint strength and residual stress of the plates were determined using mathematical models, i.e. second-degree polynomials. A clear correlation was observed between the joint strength and the post-machining residual stress. Moreover, the stress values could be controlled. Pneumatic ball peening was found to be an easy and effective method for improving the joint strength (up to 57%) of SLJs.     

Standard atomic weights of the elements (1988)

Standard atomic weights of the elements (1988)