When faced with the challenge of forming a portfolio containing a risky and a risk-free asset, investors tend to apply the same portfolio weights independently of the volatility of the risky asset. This “percentage heuristic” can lead to different levels of portfolio risk when the same investor is presented with a more or a less risky asset. Using four experiments, we show that asking investors to choose the return distribution for their portfolio while keeping the exact portfolio weights unknown leads to greater similarity in levels of portfolio volatility (across different levels of risk of the risky asset) than asking investors to choose this distribution while additionally facing the portfolio weights. Higher consistency in risk taking is obtained both between and within test subjects.

Argon physisorption at 87 K is the new standard for texture analysis of microporous media recommended by the International Union of Pure and Applied Chemistry (IUPAC). However, geoscientists routinely use nitrogen (77 K) and carbon dioxide (273 K), both molecules with permanent polarization and the preference to interact with specific surface sites. In this work, N2, CO2, and Ar physisorption isotherms were measured and classical physisorption theories applied to investigate the suitability of Ar physisorption for the porosity assessment of mudrocks, clays, and (non)-porous analogs.

N2 and Ar physisorption isotherms are qualitatively similar with the most significant discrepancies in the submonolayer range. Textural parameters reveal linear relations but parameter ratios vary randomly, independent of the sorbent class. While N2 and CO2 (mostly) underestimate micropore volumes, nitrogen BET areas are consistently larger than argon BET areas. Those differences are probably associated with differences in polarization. But its effect on molecular orientation, for example, is presumably masked by microporosity and a narrow spacing of specific surface sites.

Mesopore size distributions and Gurvich (total) pore volumes agree well for N2 and Ar indicating similar pore size and pore volume access. Combining both parameters proves effective in identifying saturation pressure offsets which pose the largest uncertainty factor in the present study. Ar-based micropore size distributions reveal three distinct classes of mudrocks differing in organic matter maturity, and its contribution to microporosity. Empirical αs plots corroborate this classification underlining the discrepancies in the micropore range of mudrocks. Comparative hysteresis loop analysis indicated cavitation as one dominant evaporation mechanism in mudrocks and clays effecting a sample-specific compartmentalization of their pore networks.

The maximum temperature that a geotechnical bentonite barrier in a deep geological repository for radioactive waste can withstand while maintaining its integrity and meeting safety requirements is still an open question. Therefore, an international consortium set up an in situ heater test (HotBENT experiment) at the Grimsel Test Site (GTS) in Switzerland at relevant scales and gradients with temperatures ranging from 175°C to 200°C at the heater/canister surface. After dismantling (5 and 20 years, respectively), the identification of bentonite alteration processes of (clay) minerals has to be based on the comparison of data with reference values determined before the heating started. The experiment was set up using ~150 tons of two different clays (Wyoming and BCV from the Czech Republic) provided in different batches. The bentonites were used both as compacted bentonite blocks and as granular bentonite material (GBM). The determination of representative mineralogical and geochemical bentonite reference values must be based on a significant number of samples taken from all parts of the experiment, which is presented here. Most of the compositional variability was close to the accuracy of the methods used. However, chemical, mineralogical and exchangeable cation analyses showed that different raw materials were used to produce the BCV top blocks. The Wyoming bentonite used is similar to MX80 bentonite in that it is dominated by Na-rich smectite, but the HotBENT material contains slightly more feldspar and zeolite and slightly less smectite. Overall, 55 samples were analysed from different parts of the experiment, providing a statistical basis for post-excavation investigations.

The paper investigates approaches for implementing circular economy strategies, such as designing mechatronic products for longer service life by replacing, upgrading, or remanufacturing subsystems. The research aims at applying MBSE to provide the necessary support for dealing with the complexity of these approaches. Requirements and challenges for the development of MBSE support in this context are examined. An example of an EV battery system model shows the benefits and challenges of comprehensive system modelling and traceability in the context of circular economy strategies.

Ilmenau is a relatively small town in a beautiful landscape, close to the centre of Germany. Since 1894 it has been the home of a Technical College which after World War II and through some permutations became today’s Technische Universität Ilmenau. For 70 years the university has contributed to Design Science. It is interesting to note that the fundamentals were developed in practice, at the Carl Zeiss company in Jena; it was only later that the new ideas were further developed for academic research and teaching in Ilmenau. The origins at Zeiss Jena still account for the main application area at Technische Universität Ilmenau today: Precision Engineering which, in addition to mechanical, has always included electric, electronic, control, software, and even optical components (“mechatronics” before the term was coined). This article – written by three (out of four in total) of the professors who were and are, respectively, in charge over almost 50 out of the 70 years – tells the story of Design Science in Ilmenau: background, beginnings, development, contributions to research, teaching, and transfer to industry. As Ilmenau was situated in the German Democratic Republic (“East Germany”) between 1949 and 1990, the story is not free of political and societal implications, some of them quite surprising.

The influence of water vapor on bentonites or smectites is of interest in many different fields of applied mineralogy such as nuclear-waste sealing or casting in the foundry industry. The water vapor affects the smectite surface and perhaps its structure probably leading to mostly unfavorable changes in its properties. In this first part of the present study, the influence of hot water vapor (200°C) on the physicochemical and mineralogical properties of smectite-group minerals was studied. After the steam treatment, turbidity measurements, methylene-blue sorption, water adsorption, and cation exchange capacity (CEC) were measured on both untreated and treated samples. Mineralogical changes were monitored by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) was used to measure O, Al, and Si. Only a few parameters showed differences between the untreated and vapor-treated samples. Sedimentation volumes (SV) decreased following the treatment. As shown by XRD and XPS, the crystalline structure of smectite remained unaffected by the steam treatment. Equivalent sphere diameters (ESD) were not affected systematically by the steam treatment. Differences in CEC values between untreated and treated samples were observed, but only for smectites with monovalent interlayer cations. From the variety of different measurements the conclusion of the present study was that steam treatment changes the charge properties at or near the smectite particle surface.

The electrical state of the interface between a kaolinite-dominated clay sample and aqueous electrolyte solutions was characterized using low-frequency conductance measurements. From these measurements, the ζ-potential and surface conductivity contributions from the diffuse and non-diffuse parts of the electrical double layer were obtained. The suspensions were studied as a function of volume fraction, electrolyte concentration, and electrolyte type (LiCl, NaCl, KCl, CsCl, CaCl2, SrCl2, and BaCl2). Interpretation in terms of the surface conductance revealed that a substantial part of the surface conductivity originates in the inner part of the double layer. Electrokinetic potentials and related diffuse double layer properties are highly dependent on the nature of monovalent counterions, whereas divalent counterions do not show such clear dependencies. Further presented was a simple way to estimate the order of magnitude of counterion mobilities in the inner part of the electrical double layer. All counterions were shown to have a substantial mobility in the inner part of the double layer. Finally, we suggest that the apparent ion-specific effects observed in the diffuse part of the double layer are at least in part related to the finite size of the counterions. Our findings are relevant to scenarios where fluid flow in porous media is accompanied by charged species transport, e.g., in electro-osmotic remediation, spectral-induced polarization, or permeability measurements.

Bentonites are proposed to be used as buffers in high-level radioactive waste repositories. The elevated temperatures in repositories may, however, affect bentonites’ desired properties. For instance, heating under dry conditions can cause cation fixation, potentially affecting swelling properties. The kinetics of mineral dissolution and precipitation reactions will equally be influenced by temperature. Redistributions of Ca-sulphates and -carbonates have been observed, as well as illitization of smectite. Illitization, however, has only been observed in laboratory experiments at large solution/solid ratios, whereas it has not yet been unambiguously identified in large-scale experiments. In many large-scale tests, cation exchange is the first observable geochemical reaction. In addition, an enrichment of Mg close to the heater is found in many such tests. The thermal gradient and (incongruent) smectite dissolution are suspected to play a role with respect to the Mg enrichment, but the underlying mechanism has not been unravelled so far. To predict the long-term performance of a bentonite buffer, numerical modelling is required in order to be able to simulate the reactions of all accompanying mineral phases. Smectites, which dominate the bentonite composition, are therefore particularly difficult to characterise, as their dissolution is often observed to be non-stoichiometric. Various model approaches exist to simulate smectite reactions, mostly based on kinetic rate reactions, ideally considering the effect of pH (congruent or incongruent dissolution), temperature and the degree of saturation of the solution. Reassessing and improving the thermodynamic/kinetic data of smectites are prerequisites for improving long-term buffer performance assessment.

Excavations at the Wacheqsa sector from Chavin de Huantar identified contexts from the Middle Formative (1100–900 BC) and Late Formative (900–550 BC) periods. We present results of starch analysis conducted in culinary equipment (ceramics) retrieved from domestic occupations and a large midden. Microbotanical analysis revealed a variety of plant food resources, such as maize, beans, olluco, and possibly chili peppers.

Model-Based Systems Engineering (MBSE) is an efficient approach to support product development in order to meet today's challenges. The MBSE approach includes methods and, above all, modelling approaches of the technical system with the aim of continuous use in development. The objective of this paper is to use the potential of the MBSE models and to show the added value of such models on the system level when used as a single source. With this objective, this paper presents a three-step approach to systematically identify and apply meaningful modelling approaches within MBSE, based on the needs during the development process. Furthermore, an FMEA example is included in this paper to elaborate the use of MBSE in the system failure analysis.

Glyphosate-resistant (GR) canola is a widely grown crop across western Canada and has quickly become a prolific volunteer weed. Glyphosate-resistant soybean is rapidly gaining acreage in western Canada. Thus, there is a need to evaluate herbicide options to manage volunteer GR canola in GR soybean crops. We conducted an experiment to evaluate the efficacy of various PRE and POST herbicides applied sequentially to volunteer GR canola and to evaluate soybean injury caused by these herbicides. Trials were conducted across Saskatchewan and Manitoba in 2014 and 2015. All treatments provided a range of suppression (>70%) to control (>80%) of volunteer canola. All treatments with the exception of the glyphosate-treated control reduced aboveground canola biomass by an average of 96%. As well, canola seed contamination was reduced from 36% to less than 5% when a PRE and POST herbicide were both used. Moreover, all combinations of herbicides used had excellent crop safety (<10%). All PRE and POST herbicide combinations provided better control of volunteer canola compared with the glyphosate-only control, but tribenuron followed by bentazon and tribenuron followed by imazamox plus bentazon provided solutions that were low cost, currently available (registered in western Canada), and had the potential to minimize development of herbicide resistance in other weeds.

In recent years, soybean acreage has increased significantly in western Canada. One of the challenges associated with growing soybean in western Canada is the control of volunteer glyphosate-resistant (GR) canola, because most soybean cultivars are also glyphosate resistant. The objective of this research was to determine the impact of soybean seeding rate and planting date on competition with volunteer canola. We also attempted to determine how high seeding rate could be raised while still being economically feasible for producers. Soybean was seeded at five different seeding rates (targeted 10, 20, 40, 80, and 160 plants m−2) and three planting dates (targeted mid-May, late May, and early June) at four sites across western Canada in 2014 and 2015. Soybean yield consistently increased with higher seeding rates, whereas volunteer canola biomass decreased. Planting date generally produced variable results across site-years. An economic analysis determined that the optimal rate was 40 to 60 plants m−2, depending on market price, and the optimal planting date range was from May 20 to June 1.

An early evaluation of a product along with the consideration of life phase specific actor(s) and environment(s) can help greatly to gain an understanding of the product's behaviour and interactions. Virtual Reality (VR) can help designers to examine later life situations of a product by means of use case scenarios. However, preparing a VR-scene is still a time-consuming and cumbersome task. A model based approach that uses behaviour models of SysML to describe a VR-scene can reduce the preparation efforts. Such an approach is helpful if it allows the reuse of already described VR-scenes or their contents. This paper talks about the reusability of SysML behaviour models that constitute a VR-scene. This reusability can only be achieved by the generic definition of model interfaces. Therefore, a new modelling approach is presented to facilitate the reuse of SysML behaviour models to form different use cases of a product in VR. This approach also talks about the interface definitions and the management of variants of SysML models. The presented approach is elaborated by an example model that contains variants and uses instances to build different use cases.

The low-frequency conductivity of aqueous kaolinite suspensions has been measured as a function of volume fraction and concentration of KCl, K2SO4 and BaCl2, respectively. These measurements were interpreted with a theoretical model accounting for surface conductivity and particle shape. For the first time, an internally consistent data set was established by measuring all parameters necessary to solve the relevant equations. The simultaneous availability of surface conductivity, surface charge density and diffuse layer charge density permitted the estimation of counterion mobilities in the stagnant layer and a consistency check for the evaluation procedure of the conductivity experiments. In agreement with current literature results, monovalent counterions were found to have a Stern layer mobility similar to their bulk mobility, whereas the mobility of divalent counterions in this layer is reduced by a factor of ∼2.

Some time ago, we reported the synthesis of bixbyite-type V2O3, a new metastable polymorph of vanadium sesquioxide. Since, a number of investigations followed, dealing with different aspects like electronic and magnetic properties of the material, the deviation from ideal stoichiometry or the preparation of nanocrystals as oxygen storage material. However, most of the physical properties were only evaluated on a theoretical basis. Here, we report the lattice dynamics and physical properties of bixbyite-type V2O3 bulk material, which we acquired from physical property measurements and neutron diffraction experiments over a wide temperature range. Besides attributing different possible orientations of the magnetic moments for V1 and V2 to the identified antiferromagnetic (AFM) ground state with a Néel temperature of 38.1(5) K, we use a first order Grüneisen approximation to determine lattice-dependent parameters for the relatively stiff cubic lattice, and, amongst others identify the Debye temperature to be as low as 350 ± 65 K.