Compressive strength of spruce glulam

Tests on glulam were simulated to determine the compressive strength. Based on the values obtained, three strength models were derived. They describe the compressive strength in terms of the density of the sawn timber used, the moisture content of the glulam and, optionally, of the knot area ratio. One of the models, based on density and moisture content, provides satisfying accuracy for engineering applications. Accordingly, glulam with 12?% moisture content has a predicted strength which is 50?% higher compared to glulam with 20?%. If the moisture content amounts to 20?% and the characteristic density of the sawn timber exceeds 350?kg/m³, the predicted strength is lower compared to corresponding nominal values in current product standards. It is suggested to separate the compressive strength for glulam with a maximum moisture content of 12?% which corresponds to service class 1 and of 20?% for service class 2. By this, significantly higher strength values could be used for compression members in service class 1.     

Did Sleeping Papers in nursing research miss their target audience?

Scientometrics - Various factors have been attributed for delayed recognition of Sleeping Papers, for example introducing new technologies which didn’t yet exist, or proposing ideas that were...     

Hydrodynamics,mass transfer,and photocatalytic phenol selective oxidation reaction kinetics in a fixed TiO2 microreactor

Photocatalytic phenol dissociation was studied in a microreactor, with a TiO₂ layer immobilized on the reactor inner walls. Experiments were conducted for various residence times, initial concentrations, pH values, and UV light irradiation intensities. The intermediates and products (catechol, hydroquinone, and resorcinol) were quantitatively investigated to determine the predominant reaction pathways for the investigated anatase catalyst. A three‐dimensional mathematical model was used to simulate the heterogeneous photocatalysis reaction conditions with Langmuir–Hinshelwood mechanism, considering the adsorption/desorption thermodynamic equilibria, and for kinetic parameter estimation via regression analysis. The effectiveness factor, Thiele modulus, and the correction function were calculated to determine the pore diffusion effects. The value of pH had the dramatic effect of lowering the reaction rate due to the competitive adsorption of hydroxide ions and protons on the catalyst surface. A phenol conversion of 79.5% was achieved at the residence time of 7.22 min, but without total mineralization. © 2014 American Institute of Chemical Engineers AIChE J, 61: 572–581, 2015     

Feeding Response to Host and Nonhost Compounds by Males and Females of the Spruce Bark Beetle <Emphasis Type="Italic">Ips typographus</Emphasis> in a Tunneling Microassay

Research on host selection by bark and wood boring insects has concentrated on flight orientation behavior. Less is known of the factors that govern the steps successive to host landing. Here, we discuss chemical factors involved in host acceptance by bark beetles and a new microassay. Adult males and females of Ips typographus were offered an artificial diet treated with various concentrations of different plant-derived compounds (host terpenes and nonhost compounds) in a no-choice mode. Beetles were tested individually in a glass tube for 4 hr, and the length of feeding was measured and compared to a control (diet with only solvent). The first effect was diet rejection, especially when nonhost compounds were tested at high concentrations. Most compounds reduced feeding, in proportion to concentration. Females were fed more readily than males after addition of both host and nonhost compounds. Diet removal was significantly affected by all the tested factors (sex, compound, dose) as well as by their interactions. With increased concentrations, males were more responsive than females to antifeedants, as all compounds (except juglone) showed clear sex differences of diet consumption. 3-Octanol, 1-hexanol, and a Green Leaf Volatile (GLV)-blend (three C6 alcohols) showed the strongest antifeedant effects, which started at a low dose (0.1%) and had a low Effective Dose 50 (ED50, 0.3–1%). In contrast, host monoterpenes, limonene and -pinene, inhibited feeding at high doses (10–30%) only with ED50 > 10%. The highest Antifeedant Indexes (AFIs) were shown by verbenone, carvone, and 1-hexanol (0.90–1.00). Both host and nonhost compounds inhibited feeding at some concentration. No significant stimulation of feeding by any host compound at concentrations reported in the literature as optimal were found, with the possible exception of -pinene at low concentrations in females.     

A personal perspective on photowork: implicit human–computer interaction for photo collection management

In the age of digital photography, the amount of photos we have in our personal collections has increased substantially along with the effort needed to manage these new, larger collections. This issue has already been addressed in various ways: from organization by meta-data analysis to image recognition and social network analysis. We introduce a new, more personal perspective on photowork that aims at understanding the user and his/her subjective relationship to the photos. It does so by means of implicit human–computer interaction, that is, by observing the user’s interaction with the photos. In order to study this interaction, we designed an experiment to see how people behave when manipulating photos on a tablet and how this implicitly conveyed information can be used to aid photo collection management.     

Globally stable model reference adaptive control based on fuzzy description of the plant

A novel fuzzy adaptive control algorithm is presented that belongs to direct model reference adaptive techniques based on a fuzzy (Takagi-Sugeno) model of the plant. The global stability of the overall system is proven, namely all the signals in the system remain bounded while the tracking error and estimated parameters converge to some residual set that depends on the size of disturbance and high-order parasitic dynamics. The hallmarks of the approach are its simplicity and transparency. The proposed algorithm is a straightforward extension of classical model reference adaptive control (MRAC) with a robust adaptive law to nonlinear systems described by fuzzy models. The performance of the approach was tested on a simulated plant and compared with the performance of a PI controller and a classical MRAC.     

A control strategy for platoons of differential drive wheeled mobile robot

The strategy for the control of vehicle platooning is proposed and tested on different mobile robot platforms. The decentralized platooning is considered, i.e. a virtual train of vehicles where each vehicle is autonomous and decides on its motion based on its own perceptions. The following vehicle only has information about its distance and azimuth to the leading vehicle. Its position is determined using odometry. The reference position and the orientation of the following vehicle are determined by the estimated path of the leading vehicle in a parametric polynomial form. The parameters of the polynomials are determined using the least-squares method. This parametric reference path is also used to determine the feed-forward part and to suppress tracking errors by a feed-back part of the applied globally stable nonlinear control law. The results of the experiment and simulations demonstrate the applicability of the proposed algorithm for vehicle platoons.     

Online fuzzy identification for an intelligent controller based on a simple platform

The paper presents the identification issues of the self-tuning nonlinear controller ASPECT (Advanced control algorithmS for ProgrammablE logiC conTrollers). The controller is implemented on a simple PLC platform with an extra mathematical coprocessor, but is intended for the advanced control of complex processes. The model of the controlled plant is obtained by means of experimental modelling. A special batch-wise algorithm that is based on the Takagi–Sugeno model and uses “fuzzy instrumental variables” technique is described in the paper. Many robustness problems of the classical adaptive approaches can be circumvented to some extent by the proposed batch-wise approach combined with a supervisory mechanism. The paper also includes some experimental results on the hydraulic pilot plant and some simulation case studies.     

Identification of dynamical systems with a robust interval fuzzy model

In this paper we present a new method of interval fuzzy model identification. The method combines a fuzzy identification methodology with some ideas from linear programming theory. On a finite set of measured data, an optimality criterion that minimizes the maximal estimation error between the data and the proposed fuzzy model output is used. The idea is then extended to modelling the optimal lower and upper bound functions that define the band that contains all the measurement values. This results in a lower and an upper fuzzy model or a fuzzy model with a set of lower and upper parameters. The model is called the interval fuzzy model (INFUMO). The method can be used when describing a family of uncertain nonlinear functions or when the systems with uncertain physical parameters are observed. We believe that the fuzzy interval model can be very efficiently used, especially in fault detection and in robust control design.     

User bias in online trust systems: aligning the system designers’ intentions with the users’ expectations

The advent of social networks opened a myriad opportunities for merging the social character of trust with the technical possibilities offered by the Internet and its availability as a mobile service. While most of the computational trust models aim to detect trustworthy entities, much less attention is paid to how these models are perceived by the users who are the core of the system. This paper delves into the workings of online trust systems under user bias and analyses the user behaviour through biases defined by Prospect theory. By performing empirical study on an existing system, we are able to demonstrate that there is a huge discrepancy between the aim of implementation of the online trust models and the users’ perception of those models. Understanding of this relation by the system designers can reduce complexity and improve the user experience and the system performance. The results imply that the tendency of the users to exhibit cognitive biases is not only the cause, but also the effect from the trust system design. These results and the analysis are then used to propose to the system designers a methodology for user bias identification and mitigation in the form of a Choice architecture for trust systems.