347 research outputs found
New Applications of Cross-Talk-Based Capacitance Measurements
No full textCharge-based capacitance measurements (CBCMs) are widely used to estimate on-chip wiring capacitances because of their accuracy and simplicity. Enhanced CMOS transducers for CBCM have been recently proposed that exploit cross-talk to selectively measure cross-coupling capacitances. In this paper we propose two new applications of cross-talk-based capacitance measurements: mismatch measurement of stacked metal-metal capacitor pairs, and localization of wire interruptions. We present the measurement techniques, we discuss their implementation and we report preliminary experimental results
Method And Relative Test Structure For Measuring The Coupling Capacitance Between Two Interconnect Lines
No full textA method and a relative test structure for measuring the coupling capacitance between two interconnect lines exploits the so-called cross-talk effect and keeps an interconnect line at a constant reference voltage. This approach addresses the problem of short-circuit currents that affect known test structures, and allows a direct measurement of the coupling capacitance between the two interconnect lines. Capacitance measurements may also be used for determining points of interruption of interconnect lines. When a line is interrupted, the measured coupling capacitance is the capacitance of a single conducting branch. The position of points of interruption of an interconnect line is determined by measuring the coupling capacitance of all segments of the line with a second conducting line
Study of Oenococcus oeni to improve wine quality
No full textLactic acid bacteria (LAB) are, besides yeasts, the best adapted microbial family to wine conditions. Many genera have been isolated both from grape must and wine, and they represent an important resource in winemaking since most of them are able to perform malolactic fermentation (MLF), the conversion of L-malic acid into L-lactic acid, which is often required to obtain wines with positive flavor and taste characteristics, but has to be avoided in some cases.
Among LAB, Oenococcus oeni is without any doubt the best adapted species to the wine environment, and is often used as a starter to perform MLF. However, this step in winemaking is often difficult to induce and control. Moreover, this microorganism requires up to 10 days to grow and develop countable colonies on plate using classical microbiological methods to enumerate viable cells, and the control of the inoculation, as well as the evaluation of the presence or absence of O. oeni in a sample, requires usually a considerable amount of time. For these reasons one of the purposes of this research project was the development of a Propidium monoazide - quantitative PCR (PMA-qPCR) technique for the fast enumeration of O. oeni in must and wine, and the results obtained show how the developed technique is able to provide a detection limit (0.33 log CFU/mL in must and 0.69 log CFU/mL in wine) which is lower than all of the other molecular biology techniques developed until now.
Furthermore, to better understand which conditions are the most favorable for a successful MLF, a Reverse Transcription – quantitative PCR (RT-qPCR) technique has been developed to study the gene expression levels of the mleA gene, encoding for the malolactic enzyme, in O. oeni. The results obtained show that co-inoculation with Saccharomyces cerevisiae and high concentrations of ethanol in the medium are the best conditions to ensure high levels of transcription of the mleA gene.
Besides the capacity of performing MLF, LAB are capable to influence the aromatic complexity of wine thanks to the release of volatile compounds due to the activity of the β-glucosidase enzyme, which has been isolated in various strains, including O. oeni. For this reason, the last purpose of this work has been the development of a RT-qPCR technique to find out which winemaking practice (sequential inoculation or co-inoculation) is the best to ensure high levels of transcription of the gene encoding for the β-glucosidase enzyme. Results point out that during co-inoculation higher levels of expression are registered.
Therefore, and although winemakers try often to avoid this practice, co-inoculation can be considered the best winemaking scenario to ensure both rapid completion of MLF and expression of β-glucosidase encoding gene, which can lead to the release of positive aromatic volatile compounds in wine.I batteri lattici (LAB) sono, insieme ai lieviti, la famiglia microbica meglio adattata alle avverse condizioni chimiche e chimico-fisiche presenti nel vino. Molti generi sono stati isolati sia dal mosto che dal vino, ed essi rappresentano un’importante risorsa nelle pratiche enologiche, dal momento che molti sono in grado di effettuare la fermentazione malolattica (FML), la conversione dell’acido L-malico in acido L-lattico, che è spesso necessaria per ottenere vini con caratteristiche desiderate di sapore e gusto, ma che in alcuni casi deve essere evitata.
Tra i LAB, Oenococcus oeni è senza dubbio il meglio adattato alle condizioni del vino, ed è spesso usato come starter per eseguire la FML. Tuttavia questa fase è spesso difficile da indurre e controllare nella produzione del vino. In più questo microorganismo richiede fino a 10 giorni per crescere e dare origine a colonie visibili e contabili in piastra utilizzando metodi di microbiologia classica per contare le cellule vitali, e il controllo dell’inoculo, così come la valutazione della presenza o dell’assenza di O. oeni in un campione, richiede di solito una significativa quantità di tempo. Per queste ragioni uno degli scopi di questo progetto di ricerca è stato lo sviluppo di una tecnica di PCR quantitativa basata sull’uso di Propidio Monoazide (PMA-qPCR) per la rapida enumerazione di O. oeni in mosto e in vino, e i risultati ottenuti mostrano che tale tecnica presenta un limite di rilevabilità del microorganismo (0.33 log UFC/mL in mosto e 0.69 log UFC/mL in vino) più basso rispetto a tutte le altre tecniche di biologia molecolare finora sviluppate.
In seguito, per meglio comprendere quali condizioni siano le più favorevoli affinchè la FML venga eseguita con successo, è stata sviluppata una tecnica di trascrizione inversa seguita da PCR quantitativa (RT-qPCR) per studiare i livelli di espressione genica del gene mleA, codificante per l’enzima malolattico, in O. oeni. I risultati ottenuti indicano che il coinoculo con Saccharomyces cerevisiae e alte concentrazioni di etanolo nel mezzo sono le condizioni migliori per assicurare alti livelli di trascrizione del gene mleA.
Accanto alla capacità di eseguire la FML, i LAB sono in grado di influenzare la complessità aromatica del vino grazie al rilascio di composti volatili dovuto all’attività dell’enzima β-glucosidasi, che è stato isolato da diversi ceppi, anche appartenenti alla specie O. oeni. Per questa ragione l’ultimo obiettivo di questo lavoro è stato lo sviluppo di una tecnica RT-qPCR al fine di individuare quale tecnica produttiva (inoculo sequenziale o coinoculo) fosse la migliore per assicurare alti livelli di trascrizione del gene codificante per l’enzima β-glucosidasi. I risultati evidenziano che durante il coinoculo vengono registrati livelli di trascrizione più alti.
Perciò, nonostante spesso i produttori tendano ad evitare questa pratica, il coinoculo può essere considerato lo scenario migliore per assicurare una rapida conclusione della FML e alti livelli di espressione del gene codificante per l’enzima β-glucosidasi, che può condurre al rilascio di composti aromatici volatili favorevoli nel vino
Charge-based on-chip measurement technique for the selective extraction of cross-coupling capacitances
No full textWe present a simple test structure (derived from the CBCM technique proposed by Sylvester et al.) that enables the selective extraction of cross-coupling capacitance between arbitrary on-chip interconnects. We discuss the silicon implementation on a 0.18um CMOS process and report preliminary experimental result
Scaling-up of evapotranspiration measurements: The promising role of scintillometry
No full textThe assessment of evapotranspiration (ET) is of primary interest,especially for agricultural and environmental issues. Traditional micrometeorological techniques require homogenous surface and are characterized by limited footprint. Thus, they cannot be applied to assess ET over inhomogeneous and extensive surfaces, typical conditions at the catchment scale and of extensive farming systems. In this context, a suitable technique to measure turbulent fluxes is scintillometry, which can give measurements of sensible heat flux at larger scale, providing averages over heterogeneous surfaces. ET can then be estimated as residual of the energy budget. In this study, we present results from a one-week campaign held during summer 2016 in Southern Italy. We deployed a Large Aperture Scintillometer (LAS) in an extensive vineyard of 140 ha on a path length of 760 m. The site was characterized by gently slope terrain with uniform crop. In order to have reference measurements of local sensible heat flux, we deployed threesonic anemometers along the scintillometer path. The aim of the study was to test the ability of scintillometry to provide a spatially averaged flux, representative of the possibly diverse conditions in an extended footprint upwind to the measurement path. The relationship between sensible heat flux measured by EC and LAS showed to be very good for the EC station in the middle of the path, whereas off-centre areas were less represented
Spatial and temporal variability of soil respiration in relation to environmental conditions in a vineyard of northern Italy
No full textTime domain approach for the evaluation of RC delays effects in ULSI interconnect lines
No full textThe evaluation of RC effects in ULSI technology is important both for process development and for accuracy verification of back-end modeling and cad-tools. The paper proposes a new methodology with one possible implementation for the measurement of RC delays in ULSI interconnect lines (DUT). The proposed implementation has been developed at wafer level by means of a mid-complexity test circuit whose working principle is based on the comparison between the RC delay of the DUT and a well-known reference delay generated on-chip
Crosstalk-Based Capacitance Measurements: Theory and Applications
No full textGeometry scaling increases the relative effect of coupling capacitances on performance, power, and noise so that they need to be carefully taken into account during process development, characterization, and monitoring. In the last decade, charge-based capacitance measurements (CBCMs) have been widely used to estimate on-chip wiring and coupling capacitances because of their accuracy and simplicity. We provide a thorough theoretical and experimental study of CBCMs applied to the selective extraction of cross-coupling capacitances. We take a historical perspective starting from the original CBCM approach proposed by Chen in 1996, and we present a new technique for crosstalk-based capacitance measurements (CTCMs). CTCMs improve the accuracy and usability of CBCMs while reducing the complexity of the test structures. We present the theory of CTCM, we provide experimental results demonstrating its improved accuracy, and we discuss its application to a wide range of process monitoring and testing tasks. Experimental results are used throughout the paper to support the discussion
- …
