We have prepared absorbing structures for photovoltaic cells with different nanotexturization, obtained by means of a femtosecond laser, without the use of corrosive gas (under vacuum). To take in ...account the 3D structured front surface, the emitter doping has been realized by using Plasma Immersion Ion Implantation (so-called PULSION). The results show a photocurrent increase of about 30% in the laser textured zones.
The degradation kinetics of ascorbic acid was determined in orange–carrot juice treated by PEF in order to establish its shelf life. Different electric field intensities (25, 30, 35, and 40
kV/cm) ...and different treatment times (from 30 to 340
μs) were studied. The ascorbic acid degradation rate (
k) obtained was −0.009
±
0.0008
μs
−1, −0.0140
±
0.0009
μs
−1, −0.0220
±
0.0023
μs
−1 and −0.0187
±
0.0049
μs
−1 for fields of 25, 30, 35, and 40
kV/cm, respectively. The treatment selected was 25
kV/cm. The shelf life of the orange–carrot juice treated by pulses at 25
kV/cm for two times (280
μs and 330
μs) was compared with a heat-treated juice (98
°C, 21
s) kept in refrigerated storage at 2 and 10
°C. The remaining concentration of ascorbic acid in the pasteurized orange–carrot juice was 83%, whereas in the PEF-treated juice it was 90%. The ascorbic acid degradation rate in the juice stored at 2
°C was less than in the juice stored at 10
°C, and in the pasteurized juice it was greater. PEF treatment at 25
kV/cm for 280–330
μs extended the half-life of the juice stored at 2
°C to 50 days.
The application of pulsed electric fields (PEF) is one of the new non-thermal technologies being studied to evaluate their potential as alternative or complementary processes to thermal ...pasteurization. “Horchata de chufa” (tiger nut milk or earth almond milk) is of high nutritional quality and therefore has great potential in the food market, limited by its very short shelf-life. The present work studies whether PEF can be used to obtain a quality horchata and increase its shelf-life while maintaining its organoleptic characteristics. In order to do so we determined pH, total fat, peroxide index, thiobarbituric acid-reactive substances index, formol index, and peroxidase activity in natural (untreated) horchata and horchata subjected to various PEF treatments and studied their stability during refrigerated storage (2–4 °C). After PEF treatment, only peroxidase activity decreased significantly (
p
<
0.05). This parameter and pH varied during the shelf-life of the horchata, and a negative correlation was obtained between pH and peroxidase activity.
Liquid chromatography (LC) was the method chosen to evaluate the effects of high intensity pulsed electric fields (HIPEF), with different electric field intensities (25, 30, 35 and 40
kV/cm) and ...different treatment times (30–340
μs), on orange juice
cis/
trans carotenoid contents. In parallel, a conventional heat treatment (90
°C, 20
s) was applied to the orange juice in order to compare the effect on the carotenoid contents.
HIPEF processing of orange juice is an alternative to the thermal treatment of pasteurization, provided that it is kept refrigerated, because, when the most extreme conditions of this kind of treatment are applied, the decrease in the concentration of carotenoids with vitamin A activity is very small, and also most of the carotenoids identified have a slightly increased concentration after application of the most intense treatments, although always less than in untreated fresh juice. In any case, pasteurization treatment causes a greater decrease in the concentration of most of the carotenoids identified and the carotenoids with vitamin A activity. The total carotenoid concentration decreased by 12.6% in pasteurized orange juice with respect to untreated fresh orange juice, as opposed to decreases of 9.6%, 6.3% or 7.8% when fields of 25, 30 or 40
kV/cm were applied. Orange juice treated with HIPEF shows a greater tendency towards the colour yellow and a lesser tendency towards red with respect to untreated orange juice, while the luminance of the juice remains practically invariable. This tendency is less than in pasteurized orange juice.
Using a presilicide implantation approach, we demonstrate that the Schottky barrier height (SBH) of NiSi/n-Si(100) can be modulated by doping a Si substrate with a halogen species such as chlorine. ...Activation energy measurements indicate that an ultralow barrier of 0.08 eV for NiS/n-Si can be achieved when a high dose (~1 times 10 15 cm 2 ) of chlorine is implanted prior to Ni silicidation. A secondary ion mass spectroscopy analysis on the presilicide Cl-implanted NiSi shows chlorine segregates at the interface with SBH tuning from 0.68 to 0.08 eV on n-Si and a corresponding increase in hole SBH on p-Si(100). The presilicide Cl-implanted NiSi film also demonstrates an enhanced thermal stability with a low sheet resistively of < 28 muOmega even up to 850degC.
•AV disengagements are highly related to road horizontal geometry.•Automated speed is defined as the maximum speed that an AV can attain at a curve.•A framework is proposed to analyse how AVs perform ...in function of road geometry.•AV consistency is defined as the difference between automated and operating speeds.•A new Level of Service for Automated Driving is introduced.
The novel semi-autonomous vehicles are becoming a reality in our roads, being a very important technological advance with promising operational and safety improvements. However, road infrastructure must be ready to host them. The technologies of these driving automation systems require certain road conditions that are not always fulfilled, causing the systems to fail. These failures generally transfer negotiation control to drivers, which may induce a crash if they were not aware of road and traffic conditions.
This research analyses how ready the road horizontal alignment is for existing semi-autonomous systems. A Level 2 vehicle has been tested on many different horizontal curves, finding a strong relationship between the maximum speed that the autonomous system can attain and the curve geometry. This maximum speed is proposed as a new concept (automated speed) and has been found to be lower than the design, operating and posted speeds in many cases. Another new concept – automated driving consistency – arises, as the difference between automated and operating speeds. The related inconsistencies can be addressed with the new concept of Level of Service for Automated Driving (LOSAD), which summarizes how ready a corridor is for a certain driving automation system. This parameter should be determined – further certified – for any homogeneous road segment, and later informed to drivers.
Today, the main challenges for the realization of the source/drain extensions concern the ultra-low energy implantation and the activation of the maximum amount of dopants with a minimized diffusion. ...Among the different annealing processes, one solution is the laser thermal annealing. Many studies F. Torregrosa, C. Laviron, F. Milesi, M. Hernandez, H. Faik, J. Venturini, Proc. 14th International Conference on Ion Implant Technology, 2004; M. Hernandez, J. Venturini, D. Zahorski, J. Boulmer, D. Débarre, G. Kerrien, T. Sarnet, C. Laviron, M.N Semeria, D. Camel, J.L Santailler, Appl. Surf. Sci. 208–209 (2003) 345–351 have shown that the association of Plasma Immersion Ion Implantation (PIII) and Laser Thermal Process (LTP) allows to obtain junctions of a few nanometers with a high electrical activation.
All the wafers studied have been implanted by PULSION
® (PIII implanter developed by Ion Beam Services) with an acceleration voltage of 1
kV and a dose of 6
×
10
15
at./cm
2. In this paper, we compare the annealing process achieved with three excimer lasers: ArF, KrF and XeCl with a wavelength of respectively 193, 248 and 308
nm. We analyse the results in terms of boron activation and junction depth.
To complete this study, we have observed the effect of pre-amorphization implantation (PAI) before PIII process on boron implantation and boron activation. We show that Ge PAI implanted by classical beam line allows a decrease of the junction depth from 20 down to 12
nm in the as-implanted condition. Transmission Electron Microscopy (TEM) analyses were performed in order to study the structure of pre-amorphized silicon and to estimate the thickness of the amorphous layer. In order to determine the sheet resistance (
R
s
) and the junction depth (
X
j
), we have used the four-point probe technique (4PP) and secondary ion mass spectrometry (SIMS) analysis. To complete the electrical characterizations some samples have been analyzed by non-contact optical measurements. All the results are presented as a function of the laser fluence and the laser wavelength.
•A global consistency model based on inertial operating speed profile is proposed.•Inertial operating speed properly represents drivers’ expectancies.•Drivers’ expectancies are closely related to ...Short-Term Memory.•A Safety Performance Function is proposed to estimate the number of crashes.•Thresholds are proposed to define the level of consistency on a road segment.
The most important factors for road crash occurrence are infrastructure, vehicle, and human factors. In fact, infrastructure and its interaction with human factor have been thoroughly studied in recent years through geometric design consistency, which can be defined as how drivers’ expectations and road behavior relate.
Global consistency models were calibrated in the last decade to assess road safety on an entire homogeneous road segment. However, none of them include the underlying consistency phenomenon in their formulation.
Recently, a new model was developed based on the difference between the inertial operating speed profile, which represents drivers’ expectancies, and the operating speed profile, which represents road behavior. While the operating speed represents the estimated operating speed for every location along the road, the inertial operating speed aggregates for every station the operating speed effect along some distance already covered by drivers. The authors hypothesized that this ‘aggregation effect’ was connected to drivers’ expectancies, which proved to be true based on the best model fitted. However, the exact distance (or time) that should be considered to estimate the inertial operating speed still remains unknown. This paper aims to complete this model, analyzing how the inertial operating speed varies depending on different distances and periods of time. This impact is measured considering the reliability of the corresponding consistency model. The paper also covers how the inertial operating speed should be determined along the final distance or time. For this, a total of 184 homogeneous road segments along 650 km in Spain were used.
•Geometric design consistency is closely related to CO2 emissions.•CO2 emission rate increases as the geometric design consistency worse.•The design of consistent roads leads to environmentally ...sustainable highways.
Highway vehicles driving on rural roads account for more than 50% of all CO2 emissions produced by the transportation sector in Europe. Although the policy measures to mitigate Greenhouse Gas emissions are increasing, these do not include policies aimed at reducing emissions by means of highway geometric design, which significantly influences drivers’ speeds and accelerations and, consequently, plays a major role on fuel consumption and emissions.
Therefore, the main objective of this research is to study the influence of the geometric design consistency on vehicle CO2 emissions. To do this, continuous speed data were collected on 47 homogeneous road segments by means of Global Positioning System devices. Vehicle CO2 emissions were estimated by applying the VT-micro model, whereas geometric design consistency was assessed considering different global consistency models.
As a conclusion, vehicle CO2 emissions decreases as the consistency level of a homogeneous road segment increases. Specifically, a good consistency road segment has been found to present an emission rate 20–30% lower than a poor-consistent one. Therefore, the design of consistent roads allows, in addition to maximize road safety, to help to achieve more environmentally sustainable highways, reducing CO2 emission production.
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