Corrosion of carbon steel underneath a lead/potassium chloride salt mixture

High amounts of lead in waste/recycled wood fuel are known to be a contributing factor to the increased corrosion often related to this type of fuel. In combination with potassium, usually present in the fuel, low‐melting point salt mixtures between lead chloride (PbCl ₂) and potassium chloride (KCl) are expected to form. The purpose of this study is to investigate reactions in the mixed salt of PbCl ₂ and KCl and its interactions with carbon steel P265GH and its oxide. Laboratory exposures were performed in an isothermal tube furnace with a salt mixture of PbCl ₂/KCl (50/50 mol%) put on steel samples. The test duration was 24 hr at either 300°C or 340°C in an atmosphere of 100 ppm HCl and 20 vol% H ₂O in synthetic air. After exposure, the salt mixture consists of distinct areas of KCl and PbCl ₂ but also the compounds K ₂PbCl ₄ and KPb ₂Cl ₅. A general observation is that the oxide thickness increases with temperature and that areas with Pb/K‐mixed salt are frequently found in close connection to more corroded areas. Often the more lead‐rich phase KPb ₂Cl ₅ is located closest to the corrosion product indicating its importance for the corrosion.     

High frequency asynchronous magnetic bead rotation for improved biosensors

Biosensors with increasingly high sensitivity are crucial for probing small scale properties. The asynchronous magnetic bead rotation (AMBR) sensor is an emerging sensor platform, based on magnetically actuated rotation. Here the frequency dependence of the AMBR sensor's sensitivity is investigated. An asynchronous rotation frequency of 145 Hz is achieved. This increased frequency will allow for a calculated detection limit of as little as a 59 nm change in bead diameter, which is a dramatic improvement over previous AMBR sensors and further enables physical and biomedical applications.     

Does condition of Lake Whitefish spawners affect physiological condition of juveniles?

Recent declines in growth and condition of several Great Lakes lake whitefish populations have raised concerns over potential impacts on juvenile physiological condition and ultimately recruitment. To test whether the condition of spawning adults influences juvenile condition via energy allocation dynamics, we partitioned the variation in age 0 juvenile physiological condition (i.e., growth in length and weight, whole-body moisture content, energy density, and protein content) among adult male and female (i.e., body condition, muscle moisture content, energy density, and protein content) and egg (i.e., wet and dry weight, moisture content, energy density, energy content per egg, and protein content) effects using redundancy analysis. Overall, a model that included sampling site, female condition, and egg quality explained 39% of the variation in juvenile physiological condition. After partitioning out the effects of females and eggs, site explained the most variation (23%). When other factors were accounted for, neither females (1.4%) nor eggs (2.7%) explained much variation in juvenile physiological condition. Of the variables studied, female muscle energy density, muscle moisture content, and egg moisture content were most closely associated with juvenile physiological condition. Our results suggest that parental effects, such as size, age, body condition, or body composition, may not be as important as extrinsic site-related effects or density-dependent effects in determining juvenile physiological condition.     

Influence of water chemistry on the corrosion mechanism of a zirconium-niobium alloy in simulated light water reactor coolant conditions

The oxidation of the zirconium alloy E110 inf simulated nuclear power plant coolant at 310 °C is characterised using in situ Electrochemical Impedance Spectroscopy (EIS) and ex-situ microscopic observations. EIS data have been fitted to a transfer function derived from the Mixed Conduction Model. The kinetic parameters characterising the oxidation process - interfacial rate constant of oxidation, diffusion coefficient of oxygen vacancies, and field strength in the inner layer - have been estimated. The dependence of their values on LiOH/KOH/NaF content are discussed in terms of an enhanced rate of dissolution of the barrier layer at higher level of alkali and fluoride.     

From ideals towards practice: paradigmatic mismatches and drifts in method deployment

There is considerable debate in the information systems literature on how systems development methods (SDMs) are used in practice. On one side are those who take the position that these methods are not used at all. The other side posits that SDMs are used but not in the manner intended by the method developers. In practice, SDMs are adapted and modified to meet project exigencies, which results in unique methods‐in‐use in each project. We subscribe to the latter view and extend the argument by proposing that SDM modifications happen due to mismatches between the paradigmatic values inherent in the SDM, the method users and the organizational context. Further, planned modifications themselves result in shifts of paradigmatic values inherent in the SDM. To examine our contention, we conduct a case study in which we trace an SDM from its development to its deployment and use in an organization. We show where the mismatches occurred and provide explanations for the mismatches. Our results indicate that paradigm differences explain most of the mismatches, and different factors contribute to the paradigm drifts simultaneously, even towards diverging orientations. We conclude that the true value of an SDM, in addition to its tool and technique use, is a basis for examining and self‐reflecting about paradigmatic values. This is an essential part of learning to develop systems.     

Reducing Excess Noise in Au/Ti Transition-Edge Sensors

We have studied the noise spectra of Au/Ti bilayer transition-edge sensors with transition temperatures around ∼100 mK. The sensors did not include an absorber element, and were patterned into either a circular Corbino geometry, or a Corbino disk divided into four parallel sections. Both sensor types contained noise in excess of the thermodynamic phonon noise and the equilibrium Johnson noise of the sensor. However, the divided Corbino detector had a significantly lower noise level than the undivided Corbino disk, especially at bias points below the mid-point of the transition.