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Efficient amplifer operation
No full textEfficient amplifier operation. In one aspect, there is a radio transceiver device. The radio transceiver device includes a distorting unit configured to receive an input signal and distort the received input signal, thereby producing a distorted input signal. The radio transceiver device further includes a limiter configured to receive the distorted input signal and produce a limited signal based on the received distorted input signal. The radio transceiver device further includes a power amplifier configured to receive the limited signal and amplify the limited signal, thereby producing an amplified limited signal
The “Little Person” in the Brain Who Helps to Direct Our Movements
No full textThe Brain Is Organized for Maximum EfficiencyOur brains interpret the world around us, think, imagine, control our movements, and much more. This seems like a lot of work for one small organ! How can the brain control so many different tasks? The best way to deal with many duties is to distribute the work, and this is how the brain does it. Specific parts of the brain are responsible for processing what we see, controlling how we speak, regulating how we move, and so on. In a busy office building, people who need to speak to each other regularly will often have their desks near each other, but people who have very different jobs and tasks can work on separate floors. It would not make sense for members of the same team to go up and down the stairs all day when they could just sit together! Putting people with similar tasks near each other allows them to work faster. The brain uses a similar strategy. Similar brain functions are controlled by brain regions that are close to each other. This means that the brain regions that often work together can communicate quickly and efficiently
Comparison of the service life, life-cycle costs and assessment of hybrid and traditional reinforced concrete through a case study of bridge edge beams in Sweden
Get PDFThe edge beams of reinforced concrete bridges with de-icing salts sprayed experience extensive corrosion damage. The average service life of edge beams needing replacement in Sweden has been reported as only 45 years, causing great economic loss to both owners and users. Hence, finding a durable solution for edge beams would benefit society. Hybrid reinforced concrete structures, produced by adding a low-to-moderate fibre content into traditional reinforced concrete, can effectively limit the service crack width and improve resistance to chloride-induced corrosion damage. In this paper, different alternatives of hybrid and traditional reinforced edge beams were designed for a case study. The service life of the alternatives was compared by conducting chloride diffusion calculations and by applying a corrosion-induced cracking model. The economic and environmental (indicated by greenhouse gas emissions) benefits of using hybrid reinforced edge beams were assessed by life-cycle cost analysis and life-cycle assessment. The results showed that the service life of edge beams made of hybrid reinforced concrete can be prolonged by over 58%, thereby enabling a significant reduction in the total life-cycle costs and annual total greenhouse gas emissions
GotEnzymes: an extensive database of enzyme parameter predictions
Get PDFEnzyme parameters are essential for quantitatively understanding, modelling, and engineering cells. However, experimental measurements cover only a small fraction of known enzyme-compound pairs in model organisms, much less in other organisms. Artificial intelligence (Al) techniques have accelerated the pace of exploring enzyme properties by predicting these in a high-throughput manner. Here, we present GotEnzymes, an extensive database with enzyme parameter predictions by Al approaches, which is publicly available at https://metabolicatlas.org/gotenzymes for interactive web exploration and programmatic access. The first release of this data resource contains predicted turnover numbers of over 25.7 million enzyme-compound pairs across 8099 organisms. We believe that GotEnzymes, with the readily-predicted enzyme parameters, would bring a speed boost to biological research covering both experimental and computational fields that involve working with candidate enzymes
Untangling the complexity generating material delivery “schedule instability”: insights from automotive OEMs
No full textPurpose: Changes frequently made to material delivery schedules (MDSs) accumulate upstream in the supply chain (SC), causing a bullwhip effect. This article seeks to elucidate how dynamic complexity generates MDS instability at OEMs in the automotive industry. Design/methodology/approach: An exploratory multiple-case study methodology involved in-depth semistructured interviews with informants at three automotive original equipment manufacturers (OEMs). Findings: Dynamic complexity destabilizes MDSs primarily via internal horizontal interactions between product and process complexities and demand and SC complexities. A network of complexity interactions causes and moderates such instability through complexity absorption and generation and complexity importation and exportation. Research limitations/implications: The multiple-case study contributes to empirical knowledge about the dynamics of MDS instability. Deductive research to validate the identified relationships remains for Future research. Practical implications: In revealing antecedents of complexity’s effect on MDS instability, the findings imply the need to develop strategies, programs, and policies dedicated to improving capacity scalability, supplier flexibility, and the flexibility of material order fulfillment. Originality/value: Building on complexity literature, the authors operationalize complexity transfer and develop a framework for analyzing dynamic complexity in SCs, focusing on complexity interactions. The identification and categorization of interactions provide a granular view of the dynamic complexity that generates MDS instability. The identified and proposed importance of readiness of the SC to absorb complexity challenges the literature focus on external factors for explaining complexity outcomes. The results can be used to operationalize such dynamic interactions by introducing new variables and networks of relationships. Moreover, the work showcases how a complexity perspective could be used to discern the root causes of a complex phenomenon driven by non-linear relationships
Toward ultrahigh thermal conductivity graphene films
Get PDFWith increasing demands of high-performance and functionality, electronics devices generate a great amount of heat. Thus, efficient heat dissipation is crucially needed. Owing to its extremely good thermal conductivity, graphene is an interesting candidate for this purpose. In this paper, a two-step temperature-annealing process to fabricate ultrahigh thermal conductive graphene assembled films (GFs) is proposed. The thermal conductivity of the obtained GFs was as high as 3826 +/- 47 W m(-1) K-1. Extending the time of high-temperature annealing significantly improved the thermal performance of the GF. Structural analyses confirmed that the high thermal conductivity is caused by the large grain size, defect-free stacking, and high flatness, which are beneficial for phonon transmission in the carbon lattice. The turbostratic stacking degree decreased with increasing heat treatment time. However, the increase in the grain size after long heat treatment had a more pronounced effect on the phonon transfer of the GF than that of turbostratic stacking. The developed GFs show great potential for efficient thermal management in electronics devices
Comparative analysis of single and multiphase numerical frameworks for subcooled boiling flow in an internal combustion engine coolant jacket
Get PDFComputational analysis of nucleate boiling occurring in liquid cooled applications, such as internal combustion engines is often implemented within a single phase Computational Fluid Dynamics (CFD) framework, owing to low vapor fractions involved. With increase in specific power and the resulting higher thermal loads, accounting for the presence of the vapor phase using a multiphase framework is required in certain conditions, despite the higher computational costs. While detailed resolution of the liquid and vapor phases in nucleate boiling using a two fluid model is excessively computationally expensive, the homogeneous mixture multiphase framework is a good compromise between resolution and computational cost. In this article a numerical wall boiling model is implemented within both, a single phase and the mixture multiphase frameworks. Results from the two approaches are compared with measurements in a channel flow. The results from both approaches are in good agreement with experiments. The single phase approximation is valid when the vapor generation is low. The sensitivity of the results to the computational grid is also discussed in detail. Further, the two frameworks are used to simulate the heat transfer in the coolant jacket of a four-cylinder petrol engine. The results from the numerical simulations are compared with measurements. Both computational frameworks compare reasonably well with the measurements in terms of local metal temperature. However, the advantage of accounting for the vapor phase using the mixture multiphase framework is evident when the parameter related to vapor bubble interactions is analyzed in detail
Mild blanching prior to pH-shift processing of Saccharina latissima retains protein extraction yields and amino acid levels of extracts while minimizing iodine content
Get PDFThe seaweed Saccharina latissima is often blanched to lower iodine levels, however, it is not known how blanching affects protein extraction. We assessed the effect of blanching or soaking (80/45/12 \ub0C, 2 min) on protein yield and protein extract characteristics after pH-shift processing of S. latissima. Average protein yields and extract amino acid levels ranked treatments as follows: blanching-45 \ub0C ∼ control > soaking ∼ blanching-80 \ub0C. Although blanching-45 \ub0C decreased protein solubilization yield at pH 12, it increased isoelectric protein precipitation yield at pH 2 (p < 0.05). The former could be explained by a higher ratio of large peptides/proteins in the blanched biomass as shown by HP-SEC, whereas the latter by blanching-induced lowering of ionic strength, as verified by a dialysis model. Moreover, blanching-45 \ub0C yielded a protein extract with 49 % less iodine compared with the control extract. We recommend blanching-45 \ub0C since it is effective at removing iodine and does not compromise total protein extraction yield
An experimental study of the influence of Lewis number on turbulent flame speed at different pressures
No full textTo explore effects of pressure on the magnitude of the influence of differences in molecular transport coefficients on turbulent flame speed ST, experiments with statistically spherical flame kernels expanding in homogeneous isotropic turbulence in a fan-stirred bomb were performed. Flame speeds were evaluated by analyzing flame images obtained using a high-speed Schlieren technique. To reach the study goals, the measurements were done at three different pressures (P = 1, 3, and 5 atm) with three different mixtures: (i) lean (the equivalence ratio π=0.45) H2/air mixture, (ii) lean (π=0.45) H2/O2/He mixture, and (iii) the stoichiometric CH4/air mixture. Mixtures (i) and (iii) are characterized by significantly different Lewis numbers (Le=0.35 and Le~1, respectively), approximately equal thermal laminar flame thicknesses δL, and close values of the laminar flame speed SL at the three pressures. Combustion chemistry is expected to be weakly affected by substitution of N2 in mixture (i) with He in mixture (ii), with this substitution increasing Le to 0.91, but the two mixtures are characterized by significantly different δL at the three pressures and different SL at P = 3 and 5 atm. Comparison of the normalized turbulent flame speeds ST/SL obtained from the lean H2/air flames and stoichiometric CH4/air flames shows that ST/SL is significantly higher in the former flames, with the difference being significantly increased by P. These experimental data indicate a substantial increase in the magnitude of the influence of differential diffusion effects on ST with pressure. An analysis of data obtained from the lean H2/O2/He flames further supports this conclusion. Based on results of numerical simulations of complex-chemistry laminar premixed flames, the pressure-dependence of the magnitude of the influence of differential diffusion effects on ST/SL is attributed to an increase in the Zel\u27dovich number by pressure, with the latter effect being most pronounced for the lean H2/O2/He mixture
Skill-biased acquisitions? Human capital and employee mobility in small technology firms
Get PDFThe purpose of this study is to investigate the relationship between acquisitions and mobility of knowledge workers and managers in small technology companies and how individual skills and capabilities moderate this relationship. Relying on the matched employer–employee data of the Swedish high-tech sectors from 2007 to 2015, we find that acquisitions increase the likelihood of employee departures, mainly in the form of switching to another employer, but that these acquisition effects are weaker for employees with technological competences. By contrast, the acquisition effects are found to be weaker for employees with managerial competences only when acquirers have a strong employee retention motive. When acquirers do not have a strong retention motive, managers, compared to other employees, are more likely to exit the (national) labor market after acquisitions. Our results suggest that the retention motive is a critical condition to explain post-acquisition employee turnover. Both technological and managerial competences are the types of human capital valued by acquirers when they have a strong retention motive