A test circuit for measurement of clocked storage element characteristics

We present a method, on-chip test circuitry, and an error analysis, for accurate measurement of timing characteristics and power consumption of clocked storage elements. The test circuit was fabricated in 0.11 /spl mu/m CMOS technology and the measurements performed automatically using a serial scan interface. The precision and accuracy of the presented method are demonstrated by the ability to measure entire clock-to-output characteristics of flip-flops. Estimated data-to-output delay systematic measurement error is 6 ps (7%), and random error is 10 ps (11%). The method and the test circuit are applicable for delay measurements of other circuit blocks as well.     

Dual-edge triggered storage elements and clocking strategy for low-power systems

This paper describes the classification, detailed timing characterization, evaluation, and design of the dual-edge triggered storage elements (DETSE). The performance and power characterization of DETSE includes the effect of clocking at halved clock frequency and impact of load imposed by the storage element to the clock distribution network. The presented analysis estimates the timing penalty and power savings of a system based on DETSE, and gives design guidelines for high-performance and low-power application. In addition, the paper presents a class of dual-edge triggered flip-flops with clock load, delay, and internal power consumption comparable to the fastest single-edge triggered storage elements (SETSE). Our simulated results show that by halving the clock frequency, dual-edge clocking strategy can save about 50% of the power consumed by the clock distribution network, and relax the design of clock distribution system, while paying virtually no penalty in throughput.     

The Effect of the System Specification on the Optimal Selection of Clocked Storage Elements

This paper represents a departure from the conventional methods of design and analysis of clocked storage elements that rely on minimizing a fixed energy-delay metric. Instead it establishes a systematic comparison in the energy-delay design space based on the parameters of the surrounding blocks. We define the composite energy-efficient characteristic over all storage element topologies and identify the most efficient storage element depending on its position on the composite characteristic relative to other topologies within a pipeline stage. Thus, we show that an optimal design could use a mixed variety of clocked storage elements (CSEs) depending on their placement in the pipeline and critical path. Since a well-designed system has hardware intensities balanced for a given cycle, a CSE choice will be made depending on the pipeline and path intensities. We show that a meaningful comparison can be carried out only by acknowledging that the optimal design and choice of the clocked storage elements depends heavily on the application, and by analyzing the energy and delay of the clocked storage elements in context of this application. The analysis in the energy-delay space allows us to understand some intuitive design choices in a quantitative way and to identify the optimal storage element topologies for an arbitrary system specification     

Encapsulation of thyme (Thymus serpyllum L.) aqueous extract in calcium alginate beads

BACKGROUND: Encapsulation of Thymus serpyllum L. aqueous extract within calcium alginate beads was studied in order to produce dosage formulations containing polyphenolic compounds. Electrostatic extrusion was applied for encapsulation of thyme aqueous extract in alginate gel beads. In addition to hydrogel beads, heat‐dried and freeze‐dried forms of beads were examined. METHODS: Encapsulation systems were examined and compared in order to choose the optimal one with respect to entrapment efficiency, preservation of antioxidant activity and thermal behaviour under heating conditions simulating the usual food processing. RESULTS: The beads obtained with approximately 2 mg g^?1 of gallic acid equivalents encapsulated in 0.015 g mL^?1 of alginate were spheres of a uniform size of about 730 µm. Encapsulation efficiency varied in the range 50‐80% depending on the encapsulation method. Besides, the analysis reveals that the encapsulation process and the material used did not degrade the bioactive compounds, as the total antioxidant content remained unchanged. This was verified by Fourier transform infrared analysis, which proved the absence of chemical interactions between extracted compounds and alginate. Addition of a filler substance, such as sucrose and inulin, in the dried product reduced its collapse and roundness distortion during drying process. CONCLUSION: This study demonstrates the potential of using hydrogel material for encapsulation of plant poplyphenols to improve their functionality and stability in food products. Copyright © 2011 Society of Chemical Industry     

Primary beer fermentation by immobilised yeast—a review on flavour formation and control strategies

Immobilised cells are increasingly being used in bio‐industries and may also have benefits for the brewing industry. The major challenge to applying this technology successfully in breweries is focused on the main fermentation in combination with the secondary fermentation. In particular, the control and fine‐tuning of the flavour profile during the main fermentation require further investigation. In this review, the influence of immobilised cell technology on the production of the flavour‐active compounds (i.e. higher alcohols, esters and vicinal diketones) is discussed. Control strategies that are based on the manipulation of parameters during fermentation such as temperature, feed volume, wort gravity, wort composition and aeration are explained. Finally, bioreactor configurations that may facilitate immobilised cells in performing the primary fermentation are evaluated. Copyright © 2006 Society of Chemical Industry     

Comparative study of batch and continuous multi-stage fixed-bed tower (MFBT) bioreactor during wine-making using freeze-dried immobilized cells

A freeze-dried immobilized biocatalyst produced by immobilization of Saccharomyces cerevisiae AXAZ-1 yeast cells on gluten pellets and subsequent freeze-drying was used in a multistage fixed-bed tower (MFBT) bioreactor for batch and continuous wine-making. The MFBT bioreactor resulted in higher alcohol productivity compared to fermentations carried out in a packed bed (PB) bioreactor and showed an important operational stability and no decrease in activity, even at low fermentation temperature (5 °C) and after storage for 6 months at 4 °C. The production of amyl alcohols proved to be temperature dependent and was significantly reduced at low temperatures. Re-activation of the freeze-dried immobilized cells after storage for 6 months resulted in further decreased content of amyl alcohols. The SPME GC/MS analysis of volatile compounds revealed no significant differences in the wines produced by MFBT and PB bioreactors, while the preliminary sensory evaluation ascertained the overall improved quality of the produced wines. Potential industrial application of MFBT bioreactor is also assessed and discussed.     

A 40–44 Gb/s 3× Oversampling CMOS CDR/1:16 DEMUX

A CMOS CDR and 1:16 DEMUX fabricated in a low-cost 90 nm bulk CMOS process operates at 40-44 Gb/s and dissipates 910 mW. A quarter-rate hybrid phase-tracking/3times blind-oversampling architecture is used to improve jitter tolerance, reduce the need for high-power CML circuits, and enable frequency acquisition without a reference clock. Input data are sampled using a 24-phase distributed VCO, and a digital CDR recovers 16 bits and a 2.5 GHz clock from 48 demultiplexed samples spanning 16 UI. Conformance to the ITU-T G.8251 jitter tolerance mask (BER <10^-12 with a 2³¹-1 PRBS source) is demonstrated using both an on-chip and an external BERT.     

Investigations of cell immobilization in alginate: rheological and electrostatic extrusion studies

In this study, the process of electrostatic extrusion as a method for cell immobilization was investigated. We have assessed the effects of concentrations of yeast cells (as a model cell type) and Na alginate on the size of the resulting microbeads and attempted to rationalize the obtained findings by rheological characterization of the cell–alginate suspensions. Under the investigated conditions, microbeads, 50–600 µm in diameter, were produced and the increase in both alginate and cell concentrations resulted in larger microbeads with their sizes having higher standard deviations. Rheological characterization revealed non‐Newtonian, pseudoplastic behavior of cell–alginate suspensions with higher viscosities at higher alginate concentrations. However, the presence of cells even at high concentrations (5 × 10⁸ and 1 × 10⁹ cells mL^?1) did not significantly affect the rheological properties of the Na alginate solution. Finally, we have investigated the kinetics of alginate gelation with respect to the quantity of Ca²⁺ ions and the presence of cells. The molar ratio of α‐L ‐guluronic acid units to Ca²⁺ ions of 4:1 provided complete crosslinking. The presence of cells decreased the rate of network formation as well as the strength of the obtained Ca alginate hydrogel. Copyright © 2006 Society of Chemical Industry     

The Possibility of Producing a Special Type of Beer Made from Wort with the Addition of Grape Must

The possibility of producing a beverage by wort fermentation enriched with grape must was examined. Must, from two different varieties of grapes, was added to conventional brewer's wort. The fermentation was carried out using a traditional method for lager beer production with the entire process taking thirty days. Following the fermentation process, a sensory analysis of the final product was performed and the total polyphenol content was determined. The results obtained suggest that it is possible to produce a pleasant beverage with some sensory properties similar to conventional beer. In addition to acceptable sensory properties, this drink was characterized by a higher alcohol (7–7.5% v/v) and polyphenol content.