Closed-loop control of hydraulic telescopic handler

Automatization is supposed to improve working conditions and safety in the construction industry, as it already did in manufacturing industries. This paper presents the development of a robotic control system for a commercially available hydraulic telescopic handler. The target application for the telescopic handler is semi-automated assembly of facade panels. The base handler was upgraded with two additional hydraulic axes, position sensors and closed-loop control system, while the original handler safety assurance mechanisms were preserved. The control approach is based on a PI controller with velocity feedforward and valve overlap compensation. The direct and inverse kinematic models of handler mechanism were developed to enable control of end-effector motion along a straight line in the Cartesian coordinate system. The motion performances were evaluated following the ISO 9283 standard with payload of 2000 kg. Results show the repeatability of positioning bellow 7.0 mm and the straight line tracking error smaller than 63 mm.     

Partial factors for imposed loads in areas for storage and industrial use

The procedures for reliability verification of new or existing buildings are calibrated to account for uncertainties and variability of resistance and load parameters. However, present standards often provide a single approach to specification of design values of all imposed loads on buildings without particular distinction between loads associated with considerable uncertainties and well-defined loads. While the former are represented by common loads in office and residential buildings, the latter, including loads due to storage of materials, material handling equipment, machinery or tanks, require different approaches for estimating design values. This contribution identifies the characteristics of well-defined imposed loads and proposes a methodology for calibrating partial factors. Key steps of the methodology consist of assessing static load effect, dynamic amplification if relevant, model uncertainty, sensitivity factors and target reliability. Careful consideration of these influences then yields partial factors that reflect reduced uncertainties in estimating the effects of well-defined imposed loads. It appears that the commonly accepted partial factor of 1.5 in Eurocodes may be reduced. When multiple crossings are considered, the partial factor can be taken independent of the number of crossings while the characteristic value is adjusted. Further studies should be particularly focused on advanced probabilistic modelling of dynamic amplification and of model uncertainties.     

Coupling dark fermentation and microbial electrolysis to enhance bio-hydrogen production from agro-industrial wastewaters and by-products in a bio-refinery framework

The aim of this work is to evaluate biohydrogen production from agro-industrial wastewaters and by-products, by combining dark fermentation and microbial electrolysis in a two-step cascade process. Such coupling of both technologies constitutes a technological building block within a concept of environmental biorefinery where sustainable production of renewable energy is expected.Six different wastewaters and industrial by-products coming from cheese, fruit juice, paper, sugar, fruit processing and spirits factories were evaluated for the feasibility of hydrogen production in a two-step process. The overall hydrogen production when coupling dark fermentation and microbial electrolysis was increased up to 13 times when compared to fermentation alone, achieving a maximum overall hydrogen yield of 1608.6 ± 266.2 mLH₂/gCOD_consumed and a maximum of 78.5 ± 5.7% of COD removal.These results show that dark fermentation coupled with microbial electrolysis is a highly promising option to maximize the conversion of agro-industrial wastewaters and by-products into bio-hydrogen.     

Promoting energy-saving behaviour: formal social groups as promising middle actors for municipal interventions

City governments worldwide are trying to motivate their citizens to reduce their energy use—a particular challenge as they try to reach individual households. A promising strategy to engage the public broadly entails collaborating with middle actors to multiply the effects of municipal interventions. Some of these middle actors are formal social groups (e.g. sports clubs and neighbourhood associations). We conducted an online experiment (N = 136) to determine whether such interventions were more effective when they are communicated through formal social groups than when communicated through city governments. Participants received letters containing advice for saving energy in the household. Willingness to participate was higher when the letters came from formal social groups than when they came from a city agency. Furthermore, actual members of formal social groups generally were more willing to participate. Our evidence suggests that formal social groups are promising middle actors for energy conservation campaigns and that city governments should engage more often with these groups to communicate with residents.     

Secondary ketonization of primary alcohol over LaMn-based mixed oxides with perovskite-like structure

LaMnO₃-based mixed oxides with perovskite-like structure both bulk and supported on La–Al₂O₃, show high catalytic activity in dehydrogenation of n-butanol to an aldehyde, which then undergoes a secondary reaction to produce a symmetrical ketone. Partial substitution of Cu, V or Sr into LaMnO₃ structure does not destroy the perovskite-like structure and enables to control the acid–base surface properties. It allows linking up these qualitative and quantitative features with activity and selectivity of these materials. The degree of n-butanol conversion depends on the total concentration of basic and acidic sites. Selectivity to butyraldehyde can be related with the share of basic sites. Selectivity to dipropyl ketone is affected both by the acidity and concentration of acidic sites. LaMnO₃/La–Al₂O₃ seems to posses an optimum set of surface characteristics for the examined ketonization of a primary alcohol.     

Do new SCI journals have a different national bias?

National shares of worldwide publications in the Science Citation Index (SCI) have shifted recently. The long-term decline in U.S. share accelerated in the mid-1990s, and now the EU has joined this decline. Not coincidentally, the shares of some countries have increased sharply, particularly those of China, S. Korea, Taiwan, and Singapore. Since the SCI constantly adds new journals, one reason might be that newly added journals were more favorable to them. To test this, the database was partitioned into “old journals” (added before 1995) and “new journals,” added afterward. The analysis was done for eight of the 20 fields of science defined by the National Science Indicator CD. In some fields, new journals were indeed much more favorable to the Asians. In some fields, however, new journals were actually more favorable to the U.S. In aggregate over the eight fields analyzed, the size of this effect was too small to account for much of the sharp changes in national shares. Furthermore tests between old and new journals find that differences in most fields are not statistically significant. The results provide evidence that the SCI can be used to accurately track national publication changes over time.     

3D monolithic integration: Technological challenges and electrical results

After a short reminder of the principle of monolithic 3D integration, this paper firstly reviews the main technological challenges associated to this integration and proposes solutions to assess them. Wafer bonding is used to have perfect crystalline quality of the top layer at the wafer scale. Thermally stabilized silicide is developed to use standard salicidation scheme in the bottom layer. Finally a fully depleted SOI low temperature process is demonstrated for top layer processing (overall temperature kept below 650 °C). In a second part the electrical results obtained within this integration scheme are summarized: mixed Ge over Si invertor is demonstrated and electrostatic coupling between top and bottom layer is used to shift the threshold voltage of the top layer. Finally circuit opportunities such as stabilized SRAM or gain in density are investigated.     

ENDER: a statistical framework for boosting decision rules

Induction of decision rules plays an important role in machine learning. The main advantage of decision rules is their simplicity and human-interpretable form. Moreover, they are capable of modeling complex interactions between attributes. In this paper, we thoroughly analyze a learning algorithm, called ENDER, which constructs an ensemble of decision rules. This algorithm is tailored for regression and binary classification problems. It uses the boosting approach for learning, which can be treated as generalization of sequential covering. Each new rule is fitted by focusing on examples which were the hardest to classify correctly by the rules already present in the ensemble. We consider different loss functions and minimization techniques often encountered in the boosting framework. The minimization techniques are used to derive impurity measures which control construction of single decision rules. Properties of four different impurity measures are analyzed with respect to the trade-off between misclassification (discrimination) and coverage (completeness) of the rule. Moreover, we consider regularization consisting of shrinking and sampling. Finally, we compare the ENDER algorithm with other well-known decision rule learners such as SLIPPER, LRI and RuleFit.