Optimal component mode synthesis for medium frequency problem

The component mode synthesis (CMS) with fixed interface (denoted Craig–Bampton) method uses a combination of static and dynamic modes. The usual definition of this CMS leads to a coupling between static and dynamic modes which are not orthogonal with respect to the stiffness matrix. This type of basis is not well suited for dynamic explicit computations, because the resulting mass matrix is not diagonal. If one keeps the same basis mode set but uses an orthogonalization process with respect to the mass matrix, the quality of the reduced Craig–Bampton system is kept but the basis vectors are combined differently. The aim of this paper is to propose a new way to control the accuracy of the reduced dynamic system for a specific frequency domain. Thus a new CMS is defined in order to be accurate in the medium frequency range. Copyright © 2010 John Wiley & Sons, Ltd.     

Receiving Phased Antenna Array Based on Injection-Locked Harmonic Self-Oscillating Mixers

A 4 times 1 element receiving phased antenna array is presented with phase-shifter elements based on injection-locked harmonic self-oscillating mixers. Each phase-shifter element provides the double functionality of variable phase-shifter and down-converter. The phase-shifts applied to the input signals coming from the different antenna patch elements can be selected by dc control signals in a continuous range of 450deg. The required dc control voltages are calculated for the different incident angles by means of harmonic balance simulations. The influences of phase-shift and conversion gain errors on the beam-steering frequency performance of the antenna are studied. Also illustrated is how the phase-shifter parameters can be optimized in order to minimize the frequency scanning. A 4 times 1 element receiving phased antenna array, with an input frequency band centered at 11.25 GHz and the output frequency band centered at 1.5 GHz, has been manufactured for the experimental validation of the simulated results. A beam scanning range from -23deg to 23deg has been experimentally obtained.     

Nonlinear Optimization of Wide-Band Harmonic Self-Oscillating Mixers

A new optimization method is presented for the design of wide-band harmonic self-oscillating mixers (HSOMs). High conversion gain is obtained through near-bifurcation operation and optimization of the harmonic content of the self-oscillation. Bifurcation analysis- and control-techniques are used in combination with nonlinear optimization techniques based on the use of an auxiliary generator. An 11.25-1.5 GHz third harmonic self-oscillating mixer (3HSOM) with a 2.5 dB down-conversion gain over a 1.2 GHz bandwidth has been designed. A good agreement between the simulated and experimental results has been found.     

Nonlinear optimization tools for the design of microwave high-conversion gain harmonic self-oscillating mixers

A new optimization method is presented for the design of microwave high-conversion gain harmonic self-oscillating mixers (SOMs). It is based on the control of the harmonic content of the transistor input-voltage waveform of the self-oscillation, through the use of a nonperturbing auxiliary generator and a substitution generator. The combination of the two generators allows obtaining the optimum harmonic content of the transistor-gate voltage waveform for a maximum conversion gain. Two different downconverter circuits have been designed using this method, a second harmonic SOM and a third harmonic SOM, obtaining a high conversion gain. A good agreement between the simulated and experimental results has been found.     

Optimal operation of a distributed energy generation system for a sustainable palm oil-based eco-community

The palm oil industry potentially can be environmentally sustainable through utilizing the vast availability of biomass residues from palm oil mills as renewable energy sources. This work addresses the optimal operation of a combined bioenergy and solar PV distributed energy generation system to meet the electricity and heat demands of an eco-community comprising a palm oil mill and its surrounding residential community. A multiperiod mixed-integer linear programming planning and scheduling model is formulated on an hourly basis that optimally selects the power generation mix from among available biomass, biogas, and solar energy resources with consideration for energy storage and load shifting. A multiscenario approach is employed that considers scenarios in the form of many possible weather conditions and various energy profiles under varying mill operation modes and residential electricity consumption. The proposed approach is demonstrated on a realistic case study for a palm oil mill in the Iskandar Malaysia economic development region. The computational results indicate that biomass-based resource is the preferred renewable energy to be implemented due to the high cost associated with solar PV. As well, load shifting and energy storage can be feasibly deployed for demand peak shaving particularly for solar PV systems.     

Fueling Open‐Source Drug Discovery: 177 Small‐Molecule Leads against Tuberculosis

With the aim of fuelling open‐source, translational, early‐stage drug discovery activities, the results of the recently completed antimycobacterial phenotypic screening campaign against Mycobacterium bovis BCG with hit confirmation in M. tuberculosis H37Rv were made publicly accessible. A set of 177 potent non‐cytotoxic H37Rv hits was identified and will be made available to maximize the potential impact of the compounds toward a chemical genetics/proteomics exercise, while at the same time providing a plethora of potential starting points for new synthetic lead‐generation activities. Two additional drug‐discovery‐relevant datasets are included: a) a drug‐like property analysis reflecting the latest lead‐like guidelines and b) an early lead‐generation package of the most promising hits within the clusters identified.     

Use of mutually coupled harmonic self-oscillating mixers for receiving phased-array antennas

A topology based on mutually coupled harmonic self-oscillating mixers for beam steering purposes in a receiver configuration is presented. The use of harmonic self-oscillating mixers increases the maximum inter-element phase-shift allowing greater steering angles. A 3 times 1 array has been manufactured showing good agreement between experimental and simulated results.     

Design and analysis of a microwave large-range variable phase-shifter based on an injection-locked harmonic self-oscillating mixer

In this letter, a new microwave variable phase-shifter based on an injection-locked harmonic self-oscillating mixer, is presented for its application in an active microstrip phased antenna array. The circuit provides the double functionality of variable phase-shifter and down-converter. Maximum conversion gain is obtained, through the optimization of a new multi-harmonic load at the input-port of the circuit. The ranges of synchronized operation are analyzed versus the circuit parameters and the corresponding phase-shifts are calculated. The stability of the synchronized solutions is analyzed using the envelope transient simulation method. An 11.25-1.5-GHz down-converter with a 3.25-GHz free-running frequency has been designed, providing a phase-shift variation at intermediate frequency up to 540/spl deg/, with a 4.5-dB conversion gain. A good agreement between the simulated and experimental results has been found.     

Phase-shifter/down-converter cell for phased-array antennas

A circuit based on an injection-locked second harmonic self-oscillating mixer is presented. The circuit provides the double functionality of variable phase shifter and down-converter. Conversion gain can be selected through the optimisation of a multiharmonic load. Phase-shift variation up to 360/spl deg/ at intermediate frequency is obtained through synchronised operation.     

Ideology, Elitism and Social Commitment: Alternative Images of Science in Two fin de siècle Barcelona Newspapers

Abstract.   This paper analyses the image of science fostered by two leading, though ideologically opposed, Barcelona newspapers at the turn of the 19th century: Conservative La Vanguardia and left-wing El Diluvio. Social tensions in the city and the leading role the press played in this context are critical to uncovering both newspapers' differing models of science popularisation, which depicted science either as a neutral, isolated endeavour or as a socially committed liberating force. El Diluvio' s utilitarian approach to science is in keeping with its objective of improving the living conditions of the working classes. Conversely, elitism might explain La Vanguardia' s top-down approach to science and its isolation in columns devoted to popularising science for its own sake. This case study reveals the existence of alternative popularisation efforts in the late nineteenth and early twentieth centuries, beyond the broadly accepted link between science popularisation and the consolidation of scientists' professional prestige.