7,641 research outputs found
On Logical Depth and the Running Time of Shortest Programs
The logical depth with significance of a finite binary string is the
shortest running time of a binary program for that can be compressed by at
most bits. There is another definition of logical depth. We give two
theorems about the quantitative relation between these versions: the first
theorem concerns a variation of a known fact with a new proof, the second
theorem and its proof are new. We select the above version of logical depth and
show the following. There is an infinite sequence of strings of increasing
length such that for each there is a such that the logical depth of the
th string as a function of is incomputable (it rises faster than any
computable function) but with replaced by the resuling function is
computable. Hence the maximal gap between the logical depths resulting from
incrementing appropriate 's by 1 rises faster than any computable function.
All functions mentioned are upper bounded by the Busy Beaver function. Since
for every string its logical depth is nonincreasing in , the minimal
computation time of the shortest programs for the sequence of strings as a
function of rises faster than any computable function but not so fast as
the Busy Beaver function.Comment: 12 pages LaTex (this supercedes arXiv:1301.4451
Aerosol and precipitation chemistry in a remote site in Central Amazonia: the role of biogenic contribution
International audienceA long-term (2?3 years) measurement of aerosol and precipitation chemistry was carried out in a remote site in Central Amazonia, Balbina, (1°55' S, 59°29' W, 174 m above sea level), about 200 km north of Manaus city. Aerosols were sampled using stacked filter units (SFU), which separate fine (d<2.5 ?m) and coarse mode (2.5 ?
Mechanical and tribological characterization of four commercial braking formulation materials
Organic friction materials for brake linings, namely brake pads are polymer matrix
composites usually containing numerous macroscopic as well as microscopic
constituents such as filamentary reinforcements, solid lubricants, abrasives and fillers.
Their main objective of the these composite system are that a constant and stable
coefficient of friction (COF) is provided irrespective of environmental conditions such
as pressure, sliding velocity, temperature, humidity etc. Brake pads performance
should be maintained over a wide range of stress conditions. Although the wear of the
brake pad is inevitable, it should be minimized as far as possible. While cast iron has
been the dominant material for brake discs, brake pad materials are constantly
evolving into more complex composites.
The main objectives of the present work is to characterize the physical and the
tribological behavior of four commercial braking pads material formulations. For all
compositions the studied factors are normal pressure and sliding speed, considering
one braking-test protocol designed with temperature and friction load data acquisition.
A double pad-on-disc tribological test configuration was used to determine tribological
properties of brake pad for heavy vehicles commercial. Three wear tests via increased
severity of rubbing conditions for a constant braking distance.The authors acknowledge Auto Travões Viseu-recondicionamento de Travões e
embraiagens Lda the support through the provision of the frictrion linning materials
presented in the study
High total phenol content, antioxidant activity and mineral content in ‘Sweetheart’ cherry peel
Cherry is used for several processed products, resulting in a large volume of subproducts, mainly stones and peel. For evaluation of nutritional potential of some sub products, total phenol content (Folin-Ciocalteu reagent method), antioxidant activity (DPPH method), and calcium, magnesium, sodium, potassium and phosphorus content (ICP-AES) were determined in 'Sweetheart' cherry peel. Results were compared with those of 'Tulameen' raspberry fruit cultivated in the same region. Raspberry is recognised to having a high level of antioxidants, minerals and fibre. Average concentrations of 2793.8 mg gallic acid equivalent kg-1, 3450.9 mg TE kg-1, (Ca) 317.7, (Mg) 267.5, (Na) 9.8, (K) 2196.2, and (P) 407.5 mg kg-1 were found in 'Sweetheart' cherry peel. Regarding raspberries, concentrations of 1411.8 mg gallic acid equivalent kg-1, 2709.5 mg TE kg-1, (Ca) 281.9, (Mg) 227.2, (Na) 1.3, (K) 1646.7, and (P) 76.7 mg kg-1 were found. All nutritional concentrations in peel were significantly higher than in the remaining fruit, showing its potential for nutrition complement production.info:eu-repo/semantics/publishedVersio
Hábitos alimentares de utentes adultos do centro de saúde de Castelo Branco
Em Portugal têm vindo a revelar-se alguns erros alimentares praticados por
grande parte da população. Esses erros cometem-se por excesso de ingestão
de certo tipo de alimentos que, consequentemente, levam a problemas no
organismo, como é o caso da obesidade, diabetes, hipertensão arterial, entre
outras doenças
Thermoelectric exhaust energy recovery with temperature control through heat pipes
Currently, a great deal of the automotive industry’s R&D effort is focused on improving overall vehicle environmental and energy efficiency. For instance, one of the things that Electric Vehicles (EVs) and Hybrid cars (HEV) have in common is the recovery of waste energy, namely during braking. But, when an I.C. engine is operating (e. g. as a range extender in an EV), a large amount of energy is also wasted within the exhaust gases and with engine cooling, energy that could otherwise be recovered by different methods. This paper reports on the recovery of waste thermal energy using thermoelectric generators (TEG) for application in hybrid, extended range electric vehicles and more generally in any vehicle that could benefit from the generation of a small amount of electric current that would reduce the alternator operation time.
Although some manufacturers are trying to develop TEGs to use at exhaust temperatures, there are still no commercially available TEG modules capable of withstanding these extreme temperatures. The present work assesses the potential of the use of heat pipes (HP) as a means of transferring energy from the hot exhaust gases to the TEG modules at a compatible temperature level while minimizing the loss of efficiency due to temperature downgrading. The type of HP used in this study is called Variable Conductance Heat Pipe (VCHP), and its deployment has the advantage of inducing good temperature control.
Various types of HPs were designed, manufactured, tested and improved with the aim of enhancing the overall heat transfer process, enabling an optimal level of electric energy recovery from the referred TEG modules. This was accomplished by the testing of different fluids inside the HP and by regulating the pressure of the gas chamber. Although the system is still under improvement, the results indicate that the use of VCHPs in conjunction with thermoelectric generators is a convincing technique for recovering otherwise wasted energy from the exhaust gases.MIT Portugal (MIT-Pt/EDAM-SMS/0030/2008)Fundação para a Ciência e a Tecnologia (FCT) (bolsa SFRH / BPD / 51048 / 2010
Produção de semente genética de soja na Embrapa Trigo em 2014/2015.
bitstream/item/141071/1/ID43632-2015PLDocOnline155sojaresultadosp30.pd
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