Chemical affinities between the major volatile compounds present in a grape pomace distillate

BACKGROUND: The distillation of vinification by‐products to obtain alcoholic drinks is potentially an important source of income for the producing countries and avoids the environmental problem of waste management. Traditional technologies of distillation involve an important cost in terms of time and staff. Nowadays, companies install new distillation equipment, with high capacity and equipped with rectification columns, which is an important advance. Nevertheless, few studieshave been published concerning their correct management. In this study, the major volatile compounds were determined by gas chromatography in 61 samples of grape pomace distillate, corresponding to the fractions collected during seven complete distillation cycles. RESULTS: With a high degree of significance, the concentrations of 1,1‐diethoxyethane, propanol, hexanoate and ethyl acetate present positive correlations with the ethanol. However, those of benzyl alcohol, 2‐phenylethanol, furfurol, lactate, ethyl mirystate and diethyl succinate, were negative, which indicates that both groups of compounds were vented in the fractions of major or minor alcoholic degree, respectively. In addition, knowledge of the relationships between the volatile compounds contributes to improved management of an industrial distillation unit. CONCLUSION: The correlations established between the concentrations of the different volatile compounds indicate their physico‐chemical affinities or their biochemical origin. Copyright © 2009 Society of Chemical Industry     

Catalytic properties of cobalt-promoted Pd/HAP catalyst for CO-cleanup of H2-rich stream

The promoting effect of Co addition on the behaviour of the Pd/HAP system in WGS reaction has been investigated. Hydroxyapatite-supported bimetallic PdCo samples have been prepared by two consecutive impregnation steps with solutions of Co and Pd precursors, respectively. The resulting catalysts have been thoroughly characterised by BET, XRD, H₂-TPR, XPS, OSCC and OSC techniques.The progressive addition of cobalt drives to an abundance of the Pd species exhibiting an intimate contact with Co and an eminent enhancement of the redox properties of the Pd/Co(x)/HAP catalysts. This results in an improvement of their performance in WGS reaction. The Pd species presenting an intimate contact with cobalt seems to be the responsible of the improvement of the CO conversion. However, this PdCo interaction leads to an increase in the methanation activity at the expense of WGS activity. When small amounts of O₂ is added to the WGS mixture, the activity is exclusively enhanced in the presence of Co species exhibiting easier reducibility.     

Can we improve clinical prediction of at-risk older drivers?

Objectives

To conduct a pilot study to evaluate the predictive value of the Montreal Cognitive Assessment test (MoCA) and a brief test of multiple object tracking (MOT) relative to other tests of cognition and attention in identifying at-risk older drivers, and to determine which combination of tests provided the best overall prediction.

Methods

Forty-seven currently licensed drivers (58–95 years), primarily from a clinical driving evaluation program, participated. Their performance was measured on: (1) a screening test battery, comprising MoCA, MOT, Mini-Mental State Examination (MMSE), Trail-Making Test, visual acuity, contrast sensitivity, and Useful Field of View (UFOV) and (2) a standardized road test.

Results

Eighteen participants were rated at-risk on the road test. UFOV subtest 2 was the best single predictor with an area under the curve (AUC) of .84. Neither MoCA nor MOT was a better predictor of the at-risk outcome than either MMSE or UFOV, respectively. The best four-test combination (MMSE, UFOV subtest 2, visual acuity and contrast sensitivity) was able to identify at-risk drivers with 95% specificity and 80% sensitivity (.91 AUC).

Conclusions

Although the best four-test combination was much better than a single test in identifying at-risk drivers, there is still much work to do in this field to establish test batteries that have both high sensitivity and specificity.     

Effect of comonomer type and concentration on the equilibrium swelling and volume phase transition temperature of N‐isopropylacrylamide‐based hydrogels

The effect of incorporating a hydrophilic monomer into poly(N‐isopropylacrylamide) (polyNIPA) hydrogels on the equilibrium swelling and the volume phase transition temperature is reported here. A nonionizable monomer (acrylamide) and three ionizable monomers (itaconic acid, 2‐ethoxyethyl monoitaconate, and 2,2‐(2‐ethoxyethyl) monoitaconate) were studied. Hydrogels with larger swelling capacity than that of the polyNIPA hydrogel were obtained. With the exception of the hydrogel containing 2,2‐(2‐ethoxyethyl) monoitaconate, which did not exhibit the de‐swelling phenomena, the rest showed a volume phase transition. The hydrogels containing 85 wt % acrylamide and 15 wt % comonomer presented the higher shrinking ratio. For some compositions, the T_c of the polyNIPA hydrogel was within the desired temperature range (38–41°C) for controlled‐drug delivery in the human body. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Analysis and optimization of lateral thin-film Silicon-on-insulator (SOI) MOSFET transistors

This paper is focused on the analysis and optimization of power N-type LDMOS (LDNMOS) transistors (V_BR > 120 V) with the purpose of being integrated in a new generation of Smart-Power technology based upon a 0.18 μm SOI-CMOS technology. The influence of some important design parameters such as the shallow trench isolation (STI) length (L_STI), the N-well doping profile and the relative position of the N-well mask to the STI block are analyzed in terms of voltage capability (V_BR), specific on-state resistance (R_on-sp) and electrical safe-operating area (SOA) by means of Technology Computer-Aided Design (TCAD) numerical simulations. The evolution of the measured and simulated V_BR as a function of the substrate (handle wafer) voltage (HWV) gives good physical insight of the optimal LDNMOS drift region design configuration. LDNMOS transistors with STI lengths partially covering the drift region length leads to better combined action of R_on-sp/V_BR trade-off and electrical SOA results.     

Conversion of fogwater and aerosol organic nitrogen to ammonium,nitrate, and NOx during exposure to simulated sunlight and ozone

Although organic nitrogen (ON) compounds are apparently ubiquitous in the troposphere, very little is known about their fate and transformations. As one step in addressing this issue, we have studied the transformations of bulk (uncharacterized) organic nitrogen in fogwaters and aerosol aqueous extracts during exposure to simulated sunlight and O3. Our results show that over the course of several hours of exposure a significant portion of condensed-phase organic nitrogen is transformed into ammonium, nitrite, nitrate, and NOx. For nitrite, there was both photochemical formation and destruction, resulting in a slow net loss. Ammonium and nitrate were formed at initial rates on the order of a few micromolar per hour in the bulk fogwaters, corresponding to formation rates of approximately 10 and 40 ng m(-3) h(-1), respectively, in ambient fog. The average initial formation rate (expressed as ng (m of air)(-3) h(-1)) of NH4+ in the aqueous extracts of fine particles (PM2.5) was approximately one-half of the corresponding fogwater value. Initial formation rates of NOx (i.e., NO + NO2) were equivalent to approximately 2-11 pptv h(-1) in the three fogwaters tested. Although the formation rates of ammonium and nitrate were relatively small as compared to their initial concentrations in fogwaters (approximately 200-2000 microM) and aerosol particles (approximately 400-1500 ng m(-3)), this photochemical mineralization and "renoxification" from condensed-phase organic N is a previously uncharacterized source of inorganic N in the atmosphere. This conversion also represents a new component in the biogeochemical cycle of nitrogen that might have significant influences on atmospheric composition, condensed-phase properties, and the ecological impacts of N deposition.     

Aromatic Compounds in Wines Produced During Fermentation: Effect of Three Red Cultivars

The aromatic compounds produced during the fermentation of the red grape cultivars Caiño Tinto, Caiño Longo, and Caiño Bravo were analysed by gas chromatography (FID) on the wines of 2002 and 2003 vintages. In both years, significant differences (p < 0.001) were observed between the wines with respect to the concentrations of aromatic compounds. Caiño Longo wines had the highest concentrations of acetates and esters. The concentrations of ethyl ester and acetates in Caíño Bravo wines were comparatively very low. Principal components analysis confirmed these results: the wines made from the different cultivars and the vintages were clearly different.     

Modelling of an adsorption system driven by engine waste heat for truck cabin A/C. Performance estimation for a standard driving cycle

This paper presents the main characteristics of an innovative cooling system for the air conditioning of a truck cabin, as well as a first estimation of its performance during a standard driving cycle, obtained with a specifically developed vehicle-engine-cooling system overall model. The innovative cooling system consists of a water–zeolite adsorption–desorption system, which employs the waste heat from the engine to produce the cooling of the vehicle cabin. The developed global model is completely dynamic and is able to: reproduce the operation of the engine through a standard driving cycle, evaluate the waste heat available at the engine hydraulic loop; calculate the sequential operation of an adsorption–desorption system, calculate the condensed water per cycle, the cooling effect produced at the evaporator, and finally, the temperature and humidity evolution of the air inside the cabin. The model was validated by experimental data. The experimental tests were performed in a lab-scale adsorption chiller prototype specifically designed and realized to be driven by the low grade waste heat (80–90 °C) from the engine coolant loop of a truck. The experimental activity carried out showed that the chiller is able to generate up to 5 kW of peak cooling power at 10 °C (35 °C of condensation temperature) with a COP of 0.6. The obtained results show that the system could be able to provide a significant amount of the required cooling.