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Search Results: 1 - 10 of 2912 matches for " Cristian; "
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The RSA Cryptographic Protocol Is Not Secure  [PDF]
Cristian Dumitrescu
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.412222
Abstract:

In this article I describe a randomized algorithm based on random walks with two absorbing barriers that solves the satisfiability problem (known to be NP complete) with arbitrary high probability. As a consequence of this algorithm, I also prove that the RSA cryptographic protocol is not secure.

A Comparative Environmental Evaluation of the Coal and Natural Gas Life Cycle  [PDF]
Cristian Dinc?
Natural Resources (NR) , 2013, DOI: 10.4236/nr.2013.48060
Abstract:

Natural gas and coal are the main primary energy resources used in the Romanian energy sector, 73.7% in 2011, taking into account the fuel imports. The objective of the article consists in analyzing all the processes along the coal and the natural gas life cycle in order to assess their overall environmental impact. Two energy technologies were analyzed, for each resource: the pulverized coal combustion with supra-critical parameters and CO2 capture unit and the natural gas combined cycle. Considering the functional unit of electricity production for 1 year, it was found that the natural gas combined cycle remains the more interesting energy technology from an environmental point of view. However, the pulverized coal with supra-critical parameters equipped with a CO2 capture unit has the lowest environmental impact on the climate change. The weakest point of the coal technology is its low efficiency.

Specialization as a Personality Trait and Tendency: Introducing an Instrument of Measuring the Specialization Degree. Part 1  [PDF]
Cristian Vrachas, George Leontakianakos
Psychology (PSYCH) , 2015, DOI: 10.4236/psych.2015.615194
Abstract: Specialization constitutes a phenomenon which has been extensively researched in the framework both of the economic science—and its various structural cognitive fields—and also of the science of Biology. However, equivalent systematic attempt in evaluating the possible correlations and consequences of specialization in reference to multiple psycho-cognitive aspects of the individual’s personality is not observable from the point of view of psychological science. Objective of the current study is the introduction of a theoretical model of specialization as a dynamic variable, as a trend, and from that stand point to evaluate a person’s specialization degree in relation to other parameters of its psycho-cognitive being. In order to test the validity of the conception of specialization as a measurable factor, the Specialization Questionnaire (S.Q.) is created and introduced. More specifically, the S.Q. is aiming, on the one hand, at quantifying the degree of professional specialization and, on the other hand, at investigating the possible correlation between professional specialization and the tendency to seek for, respectively, specialized stimuli in other aspects of life, such as the personal-free time and the interpersonal relations.
Adsorption of Copper from an Ammonia-Thiosulfate Media Using DOWEX 550A Ion Exchange Resin  [PDF]
Cristian Vargas, Patricio Navarro
International Journal of Nonferrous Metallurgy (IJNM) , 2016, DOI: 10.4236/ijnm.2016.54005
Abstract: The study of copper adsorption onto ion exchange resins of anionic type is part of the gold recovery from ammonia-thiosulfate solutions, where copper is the main impurity of the system because it acts as a catalyst of gold dissolution reaction. A study is made of the adsorption and desorption of copper in the form of the ?\"\"complex in an ammonia-thiosulfate media on an ion exchange resin, DOWEX 550A, classified as a strong base, which in its inner structure has a quaternary amine functional group. In the studied pH range copper adsorption increased with increasing pH, while the presence of thiosulfate decreased it, the same as the ammonia content, due to the greater presence of cuprotetramine, \"\". Elution of the copper complexes from the resin was more efficient with sulfite than with perchlorate.
A Note on Time Discretion and the Welfare Cost of Lump-Sum Taxation  [PDF]
Cristian F. Sepulveda
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.82013
Abstract: The lump-sum tax is broadly regarded by standard optimal tax theory as the only non-distortionary tax instrument; any other tax instrument distorts relative prices and thus creates a deadweight loss. This paper discusses an unintended effect of lump-sum taxation that can be considered a distortion of the time endowment. Whenever this tax exceeds the amount of non-labor income, it reduces the taxpayer’s ability to freely allocate her time endowment. As long as the taxpayer assigns a positive value to time discretion, the lump-sum tax creates a welfare cost that has not been identified in the relevant literature. The welfare cost of the lump-sum tax could plausibly be greater than the traditional measure of deadweight loss of an equal yield labor income tax, which does not affect time discretion. Since the lump-sum tax does not unambiguously lead to a greater welfare level, we can conclude that it is not a proper efficiency standard at low levels of non-labor income. The same argument can be used to call for caution in the use of taxes based on the value of assets that are not the source of income flows, like owner-occupied property taxes and some types of wealth taxes. At low levels of non-labor income, these tax instruments will also have a negative effect on time discretion.
The Effect of Cortex Lycii on Rattus norvegicus’ Blood Glucose Level Using a High Glucose Diet  [PDF]
Hongping Tan, Cristian Vinanzaca
Journal of Diabetes Mellitus (JDM) , 2018, DOI: 10.4236/jdm.2018.84016
Abstract: One of the primary problems in the United States is diabetes. Cortex Lycii is an herb from Asia mostly used in traditional Chinese medicine. Although its main purpose is not for lowering blood glucose levels, there are studies on Cortex Lycii with other substances which have proven it can lower glucose level in type 2 diabetes rat. Unlike other experiments, this experiment only used Cortex Lycii as a single unit to see if there was any effect on blood glucose level. Also an observation was done on if Cortex Lycii could reduce blood glucose level after ingesting a high glucose diet. Rattus norvegicus was used in this project and in order for the subject to consume Cortex Lycii, the herb was boiled and the liquid was given for consumption. In order to increase the rats’ glucose levels, corn syrup and white sugar were added to the mixture. The data showed significant decrease of blood glucose when Cortex Lycii liquid was ingested. This research has shown that Cortex Lycii can be a potential treatment for hyperglycemia or diabetes. With further research, there can be an alternative treatment rather than injecting external hormones (Insulin).
Environmental Impact Assessment of GHG Emissions Generated by Coal Life Cycle and Solutions for Reducing CO2  [PDF]
Cristian Dinc?, C?lin-Cristian Cormo?, Horia Necula
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.48A2002
Abstract:

The objective of this paper consists of evaluating the coal life cycle and proposing technical solutions for reducing GHG emissions. After applying the life cycle assessment on the coal life cycle, it was noticed that the power engineering stage has a bigger environmental impact on different indicator impacts. In order to reduce the GHG emissions the CO2 chemical absorption process was integrated in the power plant based on the circulating fluidized bed combustion technology. Two cases were analyzed: super-critical and ultra-supra-critical parameters. For each case the environmental indicators (global warming potential, abiotic depletion potential, human toxicity potential, photochemical potential, acidification potential, eutrophisation potential) were evaluated in order to estimate the environmental effects on the coal life cycle with CO2 capture process. After the integration of the CO2 capture post-combustion process into the power plant, the GHG emissions decreased from 450,760 CO2 equiv. tons to

Advanced Signal Processing and Command Synthesis for Memory-Limited Complex Systems
Cristian Toma
Mathematical Problems in Engineering , 2012, DOI: 10.1155/2012/927821
Abstract: This paper presents advanced signal processing methods and command synthesis for memory-limited complex systems. For accurate measurements performed on limited time interval, some specific methods should be added. For signal processing, a robust filtering and sampling procedure performed on a specific working interval is required, so as the influence of low-amplitude and high-frequency fluctuations to be diminished. This study shows that such a signal processing method for the case of memory-limited complex systems requires the use of certain differentiation/integration procedures performed by oscillating systems, so as robust results suitable for efficient command synthesis to be available. A brief comparison with uncertainty aspects in modern physics (where quantum aspects can be considered as features of complex systems) is also presented.
Rawls y un principio de diferencia global
Dimitriu, Cristian;
Diánoia , 2011,
Abstract: in this paper i will analyze john rawls's claims against an international difference principle as presented in the law of peoples. i argue that these claims are inconsistent with the difference principle itself. if we accept them, then we will face the dilemma of either having to endorse this principle both in the domestic and the international domains or having to reject it completely. i also defend the view that rawls's possible reply to this objection relies on the dubious empirical premise that countries are blameworthy for their own failure.
Water transport and gas exchange in the non-vascular plant Dendroligotrichum dendroides (Brid. ex Hedw.)Broth. (Polytrichaceae, Bryophyta)
Atala,Cristian;
Gayana. Botánica , 2011, DOI: 10.4067/S0717-66432011000100008
Abstract: se midió la conductancia hidráulica específica (ks) y el intercambio de gases en individuos de d. dendroides (polytrichaceae, musci). ks fue más alta que en algunas coníferas y comparable con algunas angiospermas le?osas, pero la fotosíntesis (amax) fue relativamente baja. los resultados muestran que una planta no vascular puede alcanzar altos valores de ks, sugiriendo un funcionamiento "vascular" similar a las traqueófitas.
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