Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Business Model Innovation and Firm Performance: The Role of Mediation and Moderation Factors

Business model (BM) innovation is vital for today’s businesses. However, BM innovations can be irreversible, and therefore, in comparison to product, service or process innovation, entail bigger risk and ambiguity. Understanding the way in which BM innovation exerts influences over firm’s performance would help business-owners to be more effective. Based on a systematic literature review, a model to examine how BMI impacts firm performance through mediating and moderating factors was developed. Based on in-depth analysis of 37 articles, we identified twenty moderating factors classified in four groups, i.e., Firm-Characteristics, Industry-Characteristics, BM Implementation, and BM Practices, and ten mediating factors, categorized in three sub-groups, i.e., Revenue Growth, Efficiency Growth, and Enhancing the Organizational Capabilities. This paper offers the grounding for empirical research as well contribute to the development of tools to assess the effectiveness of the BMI.Information and Communication Technolog

Developing a surface acoustic wave-induced microfluidic cell lysis device for point-of-care DNA amplification

We developed a microchip device using surface acoustic waves (SAW) and sharp-edge glass microparticles to rapidly lyse low-level cell samples. This microchip features a 13-finger pair interdigital transducer (IDT) with a 30-degree focused angle, creating high-intensity acoustic beams converging 6 mm away at a 16 MHz frequency. Cell lysis is achieved through centrifugal forces acting on Candida albicans cells and glass particles within the focal area. To optimize this SAW-induced streaming, we conducted 42 pilot experiments, varying electrical power, droplet volume, glass particle size, concentration, and lysis time, resulting in optimal conditions: an electrical signal of 2.5 W, a 20 μL sample volume, glass particle size below 10 μm, concentration of 0.2 μg, and a 5-min lysis period. We successfully amplified DNA target fragments directly from the lysate, demonstrating an efficient microchip-based cell lysis method. When combined with an isothermal amplification technique, this technology holds promise for rapid point-of-care (POC) applications.Bio-Electronic

A Current Re-Use Quadrature RF Receiver Front-End for Low Power Applications: Blixator Circuit

This article presents the theory and implementation of a quadrature and differential RF front-end receiver. Combining balun, low-noise amplifier (LNA), mixer, and oscillator in a single stage, the proposed circuit, named the Blixator, is well suited for low-power applications. The baseband's transimpedance amplifier (TIA) also shares part of its dc current with the Blixator cell, resulting in sub-milliwatt power consumption. To avoid additional power and area by quadrature LO generation, the I/Q signals are generated at RF, employing the inductors already required for providing the dc current path of the LNA transistors. The expressions for gain, noise figure (NF), and phase noise of the voltage-controlled oscillator (VCO) are derived, and the behavior of the circuit is thoroughly investigated. The prototype of the Blixator receiver is implemented in a 0.18-μm CMOS technology. The experimental results show a NF of 10.5 dB, an IIP3 of -15.5 dBm, at the maximum gain, and an image rejection of 23 dB, which meets the requirements for the Bluetooth Low Energy (BLE) standard. The circuit consumes only 340-μW, from a 0.8-V supply, and its die area is 0.75 mm2.QCD/Sebastiano La

Magnetorheological elastomer composites: Modeling and dynamic finite element analysis

Magnetorheological elastomers (MREs) are polymers reinforced by ferromagnetic particles that show magnetic dependent behavior. Mixing MREs with reinforcing fibers can create a new class of material so-called “MRE composites, MRECs” with additional functionalities and properties. Here, using a Generalized Maxwell model, we proposed a new magnetic-dependent rheological model by considering the hysteresis phenomenon for MREs to predict the dynamic damping responses of MREC plates reinforced by fibers in the frequency domain. We also investigated the influence of magnetic flux intensity, the volume fraction of the fiber, the orientation angle of the fibers, the number of layers, as well as the fiber-to-matrix stiffness ratio on the natural frequency, loss factor, and mode shapes of MRECs plates. Our results suggest that homogenously increasing the elastic properties of the MRECs through the spatial distribution of fibers and changing the fiber-to-matrix stiffness ratio can effectively tailor the dynamic properties of MRECs. Tailoring these properties can provide additional freedom for the fabrication of 4D-printed MRE-based composites.With Corrigendum to “Magnetorheological elastomer composites: Modeling and dynamic finite element analysis” [Compos. Struct. 254 (2020) 112881]Biomaterials & Tissue Biomechanic

Elasticity Approach to Predict Shape Transformation of Functionally Graded Mechanical Metamaterial under Tension

The re-entrant structures are among the simple unit cell designs that have been widely used in the design of mechanical metamaterials. Changing the geometrical parameters of these unit cell structures, their overall elastic properties (i.e., elastic stiffness and Poisson’s ratio), can be simultaneously tuned. Therefore, different design strategies (e.g., functional gradient) can be implemented to design advanced engineering materials with unusual properties. Here, using the theory of elasticity and finite element modeling, we propose a fast and direct approach to effectively design the microarchitectures of mechanical metamaterials with re-entrant structures that allow predicting complex deformation shapes under uniaxial tensile loading. We also analyze the efficiency of this method by back calculating the microarchitectural designs of mechanical metamaterials to predict the complex 1-D external contour of objects (e.g., vase and foot). The proposed approach has several applications in creating programmable mechanical metamaterials with shape matching properties for exoskeletal and soft robotic devices.Biomaterials & Tissue Biomechanic

TrollMagnifier: Detecting State-Sponsored Troll Accounts on Reddit

Growing evidence points to recurring influence campaigns on social media, often sponsored by state actors aiming to manipulate public opinion on sensitive political topics. Typically, campaigns are performed through instrumented accounts, known as troll accounts; despite their prominence, however, little work has been done to detect these accounts in the wild. In this paper, we present TROLLMAGNIFIER, a detection system for troll accounts. Our key observation, based on analysis of known Russian-sponsored troll accounts identified by Reddit, is that they show loose coordination, often interacting with each other to further specific narratives. Therefore, troll accounts controlled by the same actor often show similarities that can be leveraged for detection. TROLLMAGNIFIER learns the typical behavior of known troll accounts and identifies more that behave similarly. We train TROLLMAGNIFIER on a set of 335 known troll accounts and run it on a large dataset of Reddit accounts. Our system identifies 1,248 potential troll accounts; we then provide a multi-faceted analysis to corroborate the correctness of our classification. In particular, 66% of the detected accounts show signs of being instrumented by malicious actors (e.g., they were created on the same exact day as a known troll, they have since been suspended by Reddit, etc.). They also discuss similar topics as the known troll accounts and exhibit temporal synchronization in their activity. Overall, we show that using TROLLMAGNIFIER, one can grow the initial knowledge of potential trolls provided by Reddit by over 300%.Accepted author manuscriptOrganisation and Governanc

Biohydrogen production under hyper salinity stress by an anaerobic sequencing batch reactor with mixed culture

Background: This study investigated the effect of organic loading rate (OLR) and NaCl concentration on biohydrogen production by preheated anaerobic sludge in a lab scale anaerobic sequencing batch reactor (ASBR) fed with glucose during long time operation. Methods: During ASBR operation, the OLR was increased in steps from 0.5 to 5 g glucose/L.d and NaCl addition started at an OLR of 5 g glucose/L.d, to obtain NaCl concentrations in the reactor in the range of 0.5-30 g/L. Results: With an increasing OLR from 0.5 to 5 g glucose/L.d, the biohydrogen yield increased and reached 0.8 ± 0.4 mol H2/mol glucose at an OLR of 5 g glucose/L.d. A NaCl concentration of 0.5 g/L resulted in a higher yield of biohydrogen (1.1 ± 0.2 mol H2/mol glucose). Concentrations above 0.5 g/L NaCl led to decreasing biohydrogen yield and the lowest yield (0.3 ± 0.1 mol H2/mol glucose) was obtained at 30 g/L of NaCl. The mass balance errors for C, H, and O in all constructed stoichiometric reactions were below 5%. Conclusions: The modified Monod model indicated that r (H2)max and Ccrit values were 23.3 mL H2/g VSS/h and 119.9 g/L, respectively. Additionally, ASBR operation at high concentrations of NaCl shifted the metabolic pathway from acidogenic toward solventogenic.Sanitary Engineerin

Generalizing Hybrid Integrator-Gain Systems Using Fractional Calculus

The Hybrid Integrator-Gain System (HIGS) has recently gained a lot of attention in control of precision motion systems. HIGS is a nonlinear low pass filter/integrator with a 52° phase advantage over its linear counterpart. This property allows us to avoid the limitations typically associated with linear controllers, like the waterbed effect and Bode's gain-phase relation. In this paper, we generalize HIGS by replacing the involved integer-order integrator by a fractional-order one to adapt the phase lead from 0° (linear low pass filter) to 52° (HIGS). To analyze this filter in the frequency domain, the describing function of the proposed filter, i.e., the fractional-order HIGS, is obtained using the Fourier expansion of the output signal. In addition, this generalized HIGS is implemented in a PID structure controlling a double integrator system to validate the performance of the proposed filter in the time domain, in which by changing the fractional variable from zero to one, the output varies from the response of a linear control system to a nonlinear one. Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Mechatronic Systems Desig

The Study of Kinetic and Biosorption of Pb Ion by Rice Husk from Wastewater

Abstract An agricultural waste i.e. rice husk has been used as a cheap adsorbent for the removal ofleadas a harmful heavy metal from contaminated water via adsorption. The adsorption capacity of rice husk was calculated by equilibrium models. The results showed that the adsorption process has the best accordance with Langmuir model. The kinetics of the adsorption was also investigated and obtained that the experimental data has the best fit with pseudo-second kinetic model. In this study, the effect of the adsorbent amount as well aspH value on the results was also investigated