Electromagnetic absorption of a pinned Wigner crystal at finite temperatures

We investigate the microwave absorption of a pinned, two-dimensional Wigner crystal in a strong magnetic field at finite temperatures. Using a model of a uniform commensurate pinning potential, we analyze thermal broadening of the electromagnetic absorption resonance. Surprisingly, we find that the pinning resonance peak should remain sharp even when the temperature is comparable or greater than the peak frequency. This result agrees qualitatively with recent experimental observations of the ac conductivity in two-dimensional hole systems in a magnetically induced insulating state. It is shown, in analogy with Kohn's theorem, that the electron-electron interaction does not affect the response of a harmonically pinned Wigner crystal to a spatially uniform external field at any temperature. We thus focus on anharmonicity in the pinning potential as a source of broadening. Using a 1/N expansion technique, we show that the broadening is introduced through the self-energy corrections to the magnetophonon Green's functions.Comment: 21 pages, 9 eps figure

Caracterización de la composición lignocelulósica y lípidos residuales en racimos de frutos vacíos del procesado de aceite de palma

Empty fruit bunches (EFBs) are an agro-industrial residue discarded in the environment when the fresh palm fruits are removed for oil extraction. EFBs are abundant in palm-oil-producing countries and cause environmental problems. Besides their content in lignocellulosic, EFBs also contain amounts of residual lipids from the separation process. Because the palm fruit has two main types of oil from the pulp (palm oil) or the seeds (kernal oil), the residual EFBs lipids may have different compositions. Thus, this work aimed at characterizing the lignocellulosic content and the residual lipids in two EFBs from different palm oil producers. The EFBs were classified as Type 1 and Type 2 according to their source. The results showed that Type 1 EFBs had higher lignocellulosic and fatty acid compositions, similar to palm and kernel oils, while Type 2 EFBs had lower lignocellulosic content and fatty acid composition, similar to palm oil.Los racimos de fruta vacíos (EFBs, por sus siglas en inglés) son un residuo agroindustrial que se desecha cuando se extraen las frutas frescas de palma para extraer el aceite. Los EFBs abundan en los países productores de aceite de palma, lo que genera problemas ambientales. Además de su contenido lignocelulósicos, EFBs también contiene una cantidad de lípidos residuales del proceso de separación. Debido a que la fruta de la palma tiene dos tipos principales de aceite, los de la pulpa (aceite de palma) o de las semillas (aceite de grano), los lípidos residuales de EFBs pueden tener diferentes composiciones. Por lo tanto, este trabajo tuvo como objetivo caracterizar el contenido lignocelulósico y los lípidos residuales en EFBs de diferentes productores de aceite de palma. Los EFBs se clasificaron como Tipo 1 y Tipo 2 según su fuente. Los resultados mostraron que el EFBs tipo 1 tenía una mayor composición lignocelulósica y de ácidos grasos similar a los aceites de palma y de grano, mientras que el EFBs tipo 2 tenía un contenido lignocelulósico inferior y una composición de ácidos grasos similar al aceite de palma

Spatial Correlation Of Productive Component For Peach Palm Crop And Some Physical Attributes Of Eutrochrept Soil

Currently, Brazil sells around 300 million dollars per year of peach palms (Bactris gasipaes), wherein this country is responsible for being the largest worldwide producer, exporter and consumer. In crop year of 2014, productive components of peach palms were analyzed according to soil physical properties in Registro, SP, Brazil. The objectives were to evaluate the variability of the soil attributes and define a linear and spatial correlation between the crop productive components and the soil physical properties. Geostatistical grid was installed to collect data from soil and plant, with 54 sampling points in a total area of approximately 10,000 m2. With regard to linear point of view, stem diameter and palm height was explained by direct and exponential potential model, which was highly significant due to mechanical resistance to penetration.11316317

The critical Ising model via Kac-Ward matrices

The Kac-Ward formula allows to compute the Ising partition function on any finite graph G from the determinant of 2^{2g} matrices, where g is the genus of a surface in which G embeds. We show that in the case of isoradially embedded graphs with critical weights, these determinants have quite remarkable properties. First of all, they satisfy some generalized Kramers-Wannier duality: there is an explicit equality relating the determinants associated to a graph and to its dual graph. Also, they are proportional to the determinants of the discrete critical Laplacians on the graph G, exactly when the genus g is zero or one. Finally, they share several formal properties with the Ray-Singer \bar\partial-torsions of the Riemann surface in which G embeds.Comment: 30 pages, 10 figures; added section 4.4 in version

Electricity management in the production of leadaAcid batteries: the industrial case of a production plant in Colombia

Electricity stands as the main energy used for lead-acid battery (LAB) manufacturing. This study introduces an energy management methodology to address the electricity consumption in lead-acid battery plants, improving efficiency standards. The “equivalent battery production” is introduced to define the energy performance criteria to be met in the different production sections of the battery plant. The methodology combines the guidelines of the ISO 50001 standard with the energy management framework for manufacturing plants. The result is a structured approach for detecting inefficiencies and pinpointing their sources. The management methodology was implemented during 2016. In the formation area 222 MWh were saved during 2016. This saving accounts for 3.9% less electricity than forecasted by the energy baseline of the area. Additionally, the emission of some 40 tCO2.eq. associated with the generation of the electricity production were saved. Moreover, at plant level 424 MWh were saved, which account for 3.6% less electricity than forecasted by the energy baseline of the plant. In total, around 76 tCO2.eq. were saved as a result of the electricity savings in the plant

Utilization of barley grain in substitution of corn in diets for lactation cows

In the present research work the effects of partial and total substitution of ground corn grain by dry rolled barley on the milk production and composition were evaluated. Twenty-eight Holstein cows with an average of 125 days in milk were used in a 4x4 latin square design. Once a day, the diet was supplied in a totally mixed ration. Four levels of corn substitution by barley were tested (T1 0% barley; T2 33% barley; T3 67% barley; and T4 100% barley. The experiment was carried out during 105 days. Cows were milked twice a day and contents of fat, protein, milk total solids, and somatic cell count (SCC) were established twice in each treatment period and the milk urea nitrogen (MUN) at the end of each period. The dry matter intake decreased in a linear fashion when barley replaced corn in the diet. However, the ingestion of crude protein, neutral fiber detergent and acid fiber detergent were not affected when substituting corn by barley. Linear reduction was observed in milk yield, fat corrected milk production and fat and protein contents of the milk, while the protein percentages increased in a linear way. No effect was registered concerning the levels of substitution on the protein production, total solids of the milk, SCC, MUN and on the conversion efficiency.O objetivo deste trabalho foi avaliar os efeitos da substituição total e parcial de grãos de milho moídos por grãos de cevada laminados sobre a produção e a composição do leite. Foram utilizadas 28 vacas holandesas, com média de 125 dias de lactação, em um delineamento em quadrado latino 4x4. A dieta foi fornecida na forma de dieta totalmente misturada, 1 vez ao dia. Foram testados 4 níveis de substituição de milho por cevada (T1 0% cevada; T2 33 % cevada; T3 66% cevada; e T4 - 100% cevada). O experimento teve uma duração total de 105 dias. As vacas foram ordenhadas 2 vezes ao dia e as coletas para determinação da percentagem de gordura, proteína e extrato seco total (EST) e da contagem de células somáticas (CCS) realizadas 2 vezes em cada período experimental e para determinação do nitrogênio uréico no leite (NUL) ao final de cada período. A ingestão de matéria seca decresceu linearmente quando a cevada substituiu o milho. A ingestão de proteína bruta, fibra em detergente ácido e fibra em detergente neutro não foi afetada pela substituição do milho pela cevada. Foi observada redução linear na produção de leite, produção de leite corrigido para 4% de gordura (LCG), produção e percentagem de gordura do leite, enquanto que a percentagem de proteína aumentou linearmente. A eficiência alimentar (EA) foi em média de 1,31 kg de LCG/kg de matéria seca ingerida, não sendo afetada pelas dietas. Também não houve efeito do nível de substituição sobre a produção de proteína, EST, CCS e NUL

Finite Element Analysis Of The Equivalent Stress Distribution In Schanz Screws During The Use Of A Femoral Fracture Distractor

To evaluate the mechanical stress and elastic deformation exercised in the thread/shaft transition of Schanz screws in assemblies with different screw anchorage distances in the entrance to the bone cortex, through the distribution and location of tension in the samples.An analysis of 3. D finite elements was performed to evaluate the distribution of the equivalent stress (triple stress state) in a Schanz screw fixed bicortically and orthogonally to a tubular bone, using two mounting patterns: (1) thread/shaft transition located 20. mm from the anchorage of the Schanz screws in the entrance to the bone cortex and (2) thread/shaft transition located 3. mm from the anchorage of the Schanz screws in entrance to the bone cortex. The simulations were performed maintaining the same direction of loading and the same distance from the force vector in relation to the center of the hypothetical bone. The load applied, its direction, and the distance to the center of the bone were constant during the simulations in order to maintain the moment of flexion equally constant. The present calculations demonstrated linear behavior during the experiment. It was found that the model with a distance of 20. mm between the Schanz screws anchorage in the entrance to the bone cortex and the thread/shaft transition reduces the risk of breakage or fatigue of the material during the application of constant static loads; in this model. the maximum forces observed were higher (350. Mpa). The distance between the Schanz screws anchorage at the entrance to the bone cortex and the smooth thread/shaft transition of the screws used in a femoral distractor during acute distraction of a fracture must be farther from the entrance to the bone cortex, allowing greater degree of elastic deformation of the material, lower mechanical stress in the thread/shaft transition, and minimized breakage or fatigue. The suggested distance is 20. mm. © 2016 Sociedade Brasileira de Ortopedia e Traumatologia

Entanglement, quantum phase transition and scaling in XXZ chain

Motivated by recent development in quantum entanglement, we study relations among concurrence $C$, SU$_q$(2) algebra, quantum phase transition and correlation length at the zero temperature for the XXZ chain. We find that at the SU(2) point, the ground state possess the maximum concurrence. When the anisotropic parameter $\Delta$ is deformed, however, its value decreases. Its dependence on $\Delta$ scales as $C=C_0-C_1(\Delta-1)^2$ in the XY metallic phase and near the critical point (i.e. $1<\Delta<1.3$) of the Ising-like insulating phase. We also study the dependence of $C$ on the correlation length $\xi$, and show that it satisfies $C=C_0-1/2\xi$ near the critical point. For different size of the system, we show that there exists a universal scaling function of $C$ with respect to the correlation length $\xi$.Comment: 4 pages, 3 figures. to appear in Phys. Rev.

Entanglement in quantum computers described by the XXZ model with defects

We investigate how to generate maximally entangled states in systems characterized by the Hamiltonian of the XXZ model with defects. Some proposed quantum computers are described by such model. We show how the defects can be used to obtain EPR states and W states when one or two excitations are considered.Comment: 4 pages, 1 figur

Singular open book structures from real mappings

We prove extensions of Milnor's theorem for germs with nonisolated singularity and use them to find new classes of genuine real analytic mappings $\psi$ with positive dimensional singular locus \Sing \psi \subset \psi^{-1}(0), for which the Milnor fibration exists and yields an open book structure with singular binding.Comment: more remark