910 resultados para spent Li-batteries
Resumo:
Estimating the time since discharge of a spent cartridge or a firearm can be useful in criminal situa-tions involving firearms. The analysis of volatile gunshot residue remaining after shooting using solid-phase microextraction (SPME) followed by gas chromatography (GC) was proposed to meet this objective. However, current interpretative models suffer from several conceptual drawbacks which render them inadequate to assess the evidential value of a given measurement. This paper aims to fill this gap by proposing a logical approach based on the assessment of likelihood ratios. A probabilistic model was thus developed and applied to a hypothetical scenario where alternative hy-potheses about the discharge time of a spent cartridge found on a crime scene were forwarded. In order to estimate the parameters required to implement this solution, a non-linear regression model was proposed and applied to real published data. The proposed approach proved to be a valuable method for interpreting aging-related data.
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We present calculations for the static structure and ordering properties of two lithium-based s-p bonded liquid alloys, Li-Na and Li-Mg. Our theoretical approach is based on the neutral pseudoatom method to derive the interatomic pair potentials, and on the modified-hypernetted-chain theory of liquids to obtain the liquid static structure, leading to a whole combination that is free of adjustable parameters. The study is complemented by performing molecular dynamics simulations which, besides checking the theoretical static structural results, also allow a calculation of some dynamical properties. The obtained results are compared with the available experimental data.
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[Traditions. Asie. Turquie]
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[Biblia pauperum (italien). circa 1530]
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Hysteresis cycles are very important features of energy conversion and harvesting devices, such as batteries. The efficiency of these may be strongly affected by the physical size of the system. Here, we show that in systems which are small enough, the existence of physical boundaries which produce nonhomogeneities of the interaction potential gives rise to inflections and barriers in the associated free energy. This in turn brings on irreversible processes which can be triggered under suitable external conditions imposed by a heat bath. As an example, by controlling the temperature, the state of a small system may be impelled to oscillate between two different structural configurations or aggregation states avoiding equilibrium coexistence and therefore dissipating energy. This cyclical behavior associated with a hysteresis cycle may be prototypical of energy conversion, storage, or generating nanodevices, as exemplified by Li-ion insertion batteries.
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A pêra 'Ya Li' apresenta escurecimento da polpa poucos dias após o armazenamento refrigerado. Este trabalho objetivou avaliar condições de armazenamento visando a diminuir os danos pela baixa temperatura inicial em peras 'Ya Li'. As condições iniciais estabelecidas foram: 1) 0ºC; 2) 5ºC, nos 10 primeiros dias, com redução de 0,7ºC por dia, durante sete dias; 3) 10ºC nos 10 primeiros dias, com redução de 1,4ºC por dia, durante sete dias; 4) 10º C nos 10 primeiros dias, com redução de 1,4ºC por dia, durante sete dias, sempre em atmosfera controlada (2,0kPa de O2 e < 1,0kPa de CO2); 5) 10ºC nos 10 dias iniciais, com posterior exposição direta dos frutos a 0ºC. Em seqüência aos tratamentos iniciais, os frutos foram submetidos ao armazenamento refrigerado a 0ºC, com exceção do tratamento "4" que foi mantido continuamente em atmosfera controlada. Após 52 dias de armazenamento, verificou-se escurecimento interno, superior a 68% em todos os tratamentos. As temperaturas mais elevadas, no início, não evitaram a ocorrência do escurecimento durante o armazenamento.