Characterization,design and modeling of on-chip interleaved transformers in CMOS RFICs

This paper discusses the impacts of key geometrical parameters on the performance of interleaved transformers in CMOS radio frequency integrated circuits (RFICs). It also presents a compact circuit model for the transformer based on the “2-π” model of on-chip spiral inductors. All the RLC circuit elements can be calculated from the transformer’s geometrical and process parameters. Verification with accurately calibrated electromagnetic (EM) simulation data demonstrates accurate performance prediction and good scalability for a wide range of transformers’ layout.     

Integrated Biorefinery Design with Techno-Economic and Life Cycle Assessment Tools in Polyhydroxyalkanoates Processing

To support and move toward a sustainable bioeconomy, the production of polyhydroxyalkanoates (PHAs) using renewable biomass has acquired more attention. However, expensive biomass pretreatment and low yield of PHAs pose significant disadvantages in its large-scale production. To overcome such limitations, the most recent advances in metabolic engineering strategies used to develop high-performance strains that are leading to a new manufacturing concept converting biomass to PHAs with co-products such as amino acids, proteins, biohydrogen, biosurfactants, and various fine chemicals are critically summarized. This review article presents a comprehensive roadmap that highlights the integrated biorefinery strategies, lifecycle analysis, and techno-economic assessment for sustainable and economic PHAs production. Finally, current and future challenges that must be addressed to transfer this technology to real-world applications are reviewed.     

Cold cracking in DC-cast high strength aluminum alloy ingots: An intrinsic problem intensified by casting process parameters

For almost half a century the catastrophic failure of direct chill (DC) cast high strength aluminum alloys has been challenging the production of sound ingots. To overcome this problem, a criterion is required that can assist the researchers in predicting the critical conditions which facilitate the catastrophic failure of the ingots. This could be achieved at first glance by application of computer simulations to assess the level and distribution of residual thermal stresses. However, the simulation results are only able to show the critical locations and conditions where and when high stresses may appear in the ingots. The prediction of critical void/crack size requires simultaneous application of fracture mechanics. In this paper, we present the thermo-mechanical simulation results that indicate the critical crack size distribution in several DC-cast billets cast at various casting conditions. The simulation results were validated upon experimental DC-casting trials and revealed that the existence of voids/cracks with a considerable size is required for cold cracking to occur.     

Wavelength switching of picosecond pulses generated from a self-seeded Fabry-Perot laser diode with a tilted fiber Bragg grating formed in a graded-index multimode fiber

We demonstrated the generation of wavelength-switchable picosecond pulses from a self-seeded Fabry-Perot laser diode that used a tilted fiber Bragg grating (FBG) formed in a graded-index multimode fiber as an external optical feedback element, where wavelength switching was achieved by controlling the modal distribution in the FBG. We measured the reflection spectra of multimode FBGs fabricated with different tilt angles and discussed the effects of the tilt angle on wavelength selection. By using a 20?mm long 1.65° tilted FBG and a fiber deformer to control the modal distribution in the FBG, we generated 2?GHz pulses with a wavelength switchable over 14 wavelengths at a spacing of ～0.8?nm.     

Structural Evolution and Properties of 0.3Pb(In1/2Nb1/2)O3–0.38Pb(Mg1/3Nb2/3)O3–0.32PbTiO3 Ferroelectric Ceramics with Different Sintering Times

The structural evolution and properties of 0.3Pb(In_1/2Nb_1/2)O₃–0.38Pb(Mg_1/3Nb_2/3)O₃–0.32PbTiO₃ (0.3PIN‐0.38PMN‐0.32PT) ferroelectric ceramics with different sintering times have been investigated. The content of the tetragonal phase is increased in samples sintered for more than 6 h, despite that the composition falls in the rhombohedral region of the previously established phase diagram. The results show that the metastable tetragonal phase at room temperature is induced and stabilized by the tensile residual stresses. Excessively long sintering time generally leads to grain coarsening, loss of lead, and deterioration of properties, while the increasing amount of the tetragonal phase, and the large residual tensile stress appear to improve the dielectric and electromechanical properties. This study offers new insights into the sintering of Pb‐based ferroelectric ceramics with complex compositions.     

Highly luminescent Ag+ nanoclusters for Hg2+ ion detection

A simple, low-cost and label-free Hg(2+) ion sensor has been developed by using novel luminescent Ag(+) nanoclusters (NCs) with an excellent optical property (quantum yield = 15%), an ultra-high ratio of active Ag(+) species in the NC surface (~100%), and an ultra-short diffusion path length of Hg(2+) ions to access the NC surface (~0.5 nm).     

Augmented IDEF1-based process-oriented information modeling

Disclosing explicit knowledge about a domain is the preliminary requirement for the development of generic product models or data models in this domain. Quite a few process and information modeling methods have been developed, or are under development during the past years. However, these methods and tools are not completely compatible with each other, which causes inefficiency in the development process. In order to improve the efficiency and effectiveness of model development, the augmented IDEF1-based process-oriented information modeling methodology is proposed in this paper. The proposed methodology integrates the IDEF0 process model with the enhanced IDEF1 information model by which the information requirements can be easily identified and analyzed through the corresponding process models. As these information models intend to characterize the flow of information, they are independent of any specific process models. Thus, they lay the foundation for the development of base-level representations. Finally, an example is given to demonstrate the simplicity, effectiveness, and user-friendliness of the proposed methodology to carry out information requirement analysis.     

Phosphorus models for eutrophic lakes

A model is developed for a highly eutrophic lake (White Lake, Michigan) which incorporates both the water and sediment systems and considers two forms of phosphorus—particulate and dissolved. Dynamic interactions of phosphorus between sediments and water are quantified by taking account particulate phosphorus sinking to the sediment-water interface and diffusion of dissolved phosphorus across the interface. Other model mechanisms include vertical eddy diffusion in the water; phosphorus transformation between the particulate form and the dissolved form in both the water and the sediment, diffusion of phosphorus in the interstitial water, and sedimentation in the sediments.

Extensive field data have been used to determine the coefficients and parameters defined in the model formulations. Close agreement between the model calculations and the observed data is obtained, especially for the upper layers of the sediment. Sensitivity analysis for the model further substantiates the model calculations. It is found that two separate forms of phosphorus are necessary to gain detailed insight into the dynamics of phosphorus cycling in White Lake. The model also explains significant releases of phosphorus during anaerobic periods from the sediment to the hypolimnion of White Lake in summer. The general applicability of the model to lakes having different degrees of eutrophication must be determined by an examination and analysis of data from other systems.     

Quality control and patient dosimetry in digital radiology. On line system: new features and transportability

New features have been added to a system (QCONLINE) for auditing patient dosimetric and technical parameters 'on line', working on a digital radiology department and using the information contained in the DICOM header of some modalities. The audit of other parameters than patient doses have been included, setting alarm conditions to alert on malfunction of the X-ray system or bad operation modes, in addition to the evaluation of patient doses. A new module to analyse, collect and process the relevant information transferred by the modality performed procedure step (MPPS) service has been launched. Several examples with the exploitation of the new features are presented. The transportability of the system has been tested in two remote hospitals during several months. The new MPPS module has demonstrated to be a good tool to complement the information existing in the DICOM header. The system allows to help in the optimisation of digital radiology departments managing patient dosimetry and procedure data in real time.     

Engineering the 3D architecture and hydrophobicity of methyltrichlorosilane nanostructures

Three-dimensional nano-architectures with varying shape, morphology and size were fabricated by the phase separation of methyltrichlorosilane (CH(3)SiCl(3)) on commercially available glass and SiO(2) substrates. By changing the synthesis conditions, CH(3)SiCl(3) nanostructures evolved from discrete to quasi-network or from fibrous to spherical forms. Individual nanofibers and nanospheres have diameters of 18-90 and 240-300?nm, respectively, while the film thicknesses could reach 320?nm. The possible mechanisms for the three-dimensional growth of nanofibers and nanospheres are proposed. The resultant morphologies exhibited two main energy states: Wenzel and Cassie-Baxter states. Moreover, superhydrophobic surfaces with both high contact angle and high hysteresis resulted from the growth of the nanostructures. The new approaches presented herein are important additions to the current range of surface modification methods and could harness novel physical and chemical properties conducive to optimal performance in biosensing, antistiction, droplet manipulation, drag reduction, protein adsorption, and cell adhesion studies.