Multi-Tone Microwave Locking via Real-Time Feedback

Environmental noise coupling to mechanical experiments often introduces low-frequency fluctuations to the resonators, adding noise to measurements and reducing signal to noise. To counter these fluctuations, we demonstrate a dynamic feedback system implemented by the locking of a microwave drive to the noisy cavity. A homodyne interferometer scheme monitors the cavity resonance fluctuations due to low-frequency noise, which is mitigated by frequency-modulating (FM) the microwave generator. The feedback has a bandwidth of $400$ Hz, with a reduction of cavity fluctuations by $84\%$ integrating up to a bandwidth of $2$ kHz. Moreover, the cavity resonance frequency fluctuations are reduced by $73\%$. This scheme can be scaled to enable multi-tone experiments locked to the same feedback signal. As a demonstration, we apply the feedback to an optomechanical experiment and implement a cavity-locked, multi-tone mechanical measurement. As low-frequency cavity frequency noise can be a limiting factor in many experiments, the multi-tone microwave locking technique presented here is expected to be relevant for a wide range of fields of research.Comment: 7 pages, 5 figure

Chip-to-chip entanglement of transmon qubits using engineered measurement fields

© 2018 American Physical Society. While the on-chip processing power in circuit QED devices is growing rapidly, an open challenge is to establish high-fidelity quantum links between qubits on different chips. Here, we show entanglement between transmon qubits on different cQED chips with 49% concurrence and 73% Bell-state fidelity. We engineer a half-parity measurement by successively reflecting a coherent microwave field off two nearly identical transmon-resonator systems. By ensuring the measured output field does not distinguish |01) from |10), unentangled superposition states are probabilistically projected onto entangled states in the odd-parity subspace. We use in situ tunability and an additional weakly coupled driving field on the second resonator to overcome imperfect matching due to fabrication variations. To demonstrate the flexibility of this approach, we also produce an even-parity entangled state of similar quality, by engineering the matching of outputs for the |00) and |11) states. The protocol is characterized over a range of measurement strengths using quantum state tomography showing good agreement with a comprehensive theoretical model

Desenvolvimento de software para produção de biodiesel a partir do óleo residual

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMO: A demanda por energia cresce mais a cada ano e com isso aumenta a poluição. O biodiesel existe como uma alternativa ao diesel derivado do petróleo. Biodiesel é obtido por uma reação de transesterificação entre um óleo vegetal ou gordura animal e um álcool de cadeia curta. O óleo de soja residual é uma alternativa de utilização de um resíduo para produção desse biocombustível. O presente estudo traz o desenvolvimento de um software que vem a ser apoio na produção de biodiesel a partir do óleo residual. Foram feitas reações para produção de biodiesel a partir do óleo de soja residual alterando as variáveis: tipo de catalisador (KOH e NaOH), razão molar óleo:metanol (1:5 e 1:7) e tempo de reação de reação (40 min e 1h). O maior rendimento de óleo em biodiesel de 97,30% foi obtido na reação utilizando a razão molar óleo:metanol de 1:7, KOH como catalisador na temperatura de 50ºC por 1h. O software coleta do usuário a massa do óleo, dispondo com isto o catalisador a ser utilizado, quantidade de massa do catalisador e álcool, tempo reacional, temperatura e porção necessária ou não de HCl para posterior purificação.ABSTRACT: The demand for energy grows more each year and with it increases pollution. Biodiesel exists as an alternative to diesel derived from petroleum. Biodiesel is obtained by a transesterification reaction between a vegetable oil or animal fat and a short-chain alcohol. Residual soybean oil is an alternative to using a residue to produce this biofuel. The present study brings the development of software that comes to support the production of biodiesel from residual oil. Reactions were made for the production of biodiesel from residual soy oil by changing the variables: type of catalyst (KOH and NaOH), molar ratio oil: methanol (1: 5 and 1: 7) and reaction time of reaction (40 min and 1h). The highest oil yield in biodiesel of 97.30% was obtained in the reaction using the oil: methanol molar ratio of 1: 7, KOH as a catalyst at a temperature of 50ºC for 1h. The software collects the mass of the oil from the user, thereby providing the catalyst to be used, the amount of mass of the catalyst and alcohol, reaction time, temperature and the necessary portion or not of HCl for further purification.info:eu-repo/semantics/publishedVersio

Anaerobic co-digestion of sugarcane vinasse and elephant grass juice for biomethan production.

In the present study, biogas production was investigated by co-digesting elephant grass juice (EGJ) and sugarcane vinasse using batch reactor. Some factors that influence biomethane production were observed, including initial pH, inoculum concentration and proportions of each substrate. Two tests were carried out. In Experiment I, the following proportions (%v/v sugarcane vinasse/elephant grass juice) were tested: A - 25/75, B - 50/50, C - 75/25, D - 100/0, E - 0/100. In Experiment II, the effect of adding alkalizer to the condition that showed the highest methane production (in Experiment I) was also evaluated. In the Experiment I, the highest accumulated production was observed for the proportion 1:1 corresponding to 50% of EGJ and 50% of vinasse (370.94 mLCH4/gVS). Experiment II showed the higher values of accumulated methane production of 1,364.1 mLCH4/gVS. Regarding addition of alkalizing, a maximum production of 836.18 mLCH4/gVS was obtained in the experimental condition with 50% EGJ and 50% vinasse, but with the lowest addition of alkalizer tested (0.05 g HCO3/gCOD). In general, the use of elephant grass caused the acidification of the reactors and was unfavorable for biogas production

Inovação tecnológica como agente de redução de impactos ambientais da indústria de rochas ornamentais no estado do Rio de Janeiro

A indústria de rochas ornamentais da região noroeste fluminense constitui um arranjo produtivo local de grande importância econômica. Entretanto, as empresas fazem uso de técnicas rudimentares em seus processos produtivos, o que causa sérios problemas ambientais e de competitividade. Cientes de que a principal dificuldade enfrentada por esta indústria está relacionada com a ausência de tecnologias, governo, universidades e organizações da sociedade civil têm tentado desenvolver e difundir tecnologias. O objetivo deste trabalho de pesquisa é identificar e descrever os fatores que impedem a difusão de tecnologia neste arranjo produtivo. Foram realizados múltiplos estudos de caso de caráter exploratório, descritivo e explicativo, nos quais foram utilizadas múltiplas fontes de evidência, tais como revisão bibliográfica, entrevistas semi-estruturadas com empresários e profissionais do setor, além de visitas técnicas a empresas locais. Os resultados apontam para dificuldades na difusão dessas tecnologias, especialmente para as pequenas empresas, tais como baixa qualificação de empresários e trabalhadores, resistência a mudanças dentro das empresas, e dificuldade de articulação, já que, atualmente, existe disponibilidade de recursos financeiros e apoio institucional para a inovação

ANNEXIN1 mediates calcium-dependent systemic defense in Arabidopsis plants upon herbivory and wounding.

Funder: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior; Id: http://dx.doi.org/10.13039/501100002322Cellular calcium (Ca) transients are endogenous signals involved in local and systemic signaling and defense activation upon environmental stress, including wounding and herbivory. Still, not all Ca2+ channels contributing to the signaling have been identified, nor are their modes of action fully known. Plant annexins are proteins capable of binding to anionic phospholipids and can exhibit Ca channel-like activity. Arabidopsis ANNEXIN1 (ANN1) is suggested to contribute to Ca transport. Here, we report that wounding and simulated-herbivory-induced cytosolic free Ca elevation was impaired in systemic leaves in ann1 loss-of-function plants. We provide evidence for a role of ANN1 in local and systemic defense of plants attacked by herbivorous Spodoptera littoralis larvae. Bioassays identified ANN1 as a positive defense regulator. Spodoptera littoralis feeding on ann1 gained significantly more weight than larvae feeding on wild-type, whereas those feeding on ANN1-overexpressing lines gained less weight. Herbivory and wounding both induced defense-related responses on treated leaves, such as jasmonate accumulation and defense gene expression. These responses remained local and were strongly reduced in systemic leaves in ann1 plants. Our results indicate that ANN1 plays an important role in activation of systemic rather than local defense in plants attacked by herbivorous insects

Exploring metabolic responses of potato tissue induced by electric pulses

In this study, we investigated the metabolic responses of potato tissue induced by pulsed electric field (PEF). Potato tissue was subjected to field strengths ranging from 30 to 500 V/cm, with a single rectangular pulse of 10 μs, 100 μs, or 1 ms. Metabolic responses were monitored using isothermal calorimetry, changes on electrical resistance during the delivery of the pulse, as well as impedance measurements. Our results show that the metabolic response involves oxygen consuming pathways as well as other unidentified events that are shown to be insensitive to metabolic inhibitors such as KCN and sodium azide. The metabolic response is strongly dependent on pulsing conditions and is independent of the total permeabilization achieved by the pulse. Evidence shows that calorimetry is a simple and powerful method for exploring conditions for metabolic stimulation, providing information on metabolic responses that can not be obtained from electrical measurements. This study set the basis for further investigations on defense-related consequences of PEF-induced stress.Sparbanksstiftelsen Färs & Frosta (Sweden).Fundação para a Ciência e a Tecnologia (FCT).Lund University (Sweden).Department of Cell and Organism Biology; Department of Plant Biochemistry

Effects of pulsed electric field on the viscoelastic properties of potato tissue

We have investigated whether transient permeabilization caused by the application of pulsed electric field would give rise to transient changes in the potato tissue viscoelastic properties. Potato tissue was subjected to nominal field strengths (E) ranging from 30 to 500 V/cm, with a single rectangular pulse of 10−5, 10−4, or 10−3 s. The changes on the viscoelastic properties of potato tissue during pulsed electric fields (PEF) were monitored through small amplitude oscillatory dynamic rheological measurements. The elastic (G′) and viscous moduli (G″) were measured every 30 s after the delivery of the pulse and the loss tangent change (tan-δ) was calculated. The results were correlated with measurements of changes on electrical resistance during the delivery of the pulse. Results show a drastic increase of tan-δ in the first 30 s after the application of the pulse, followed by a decrease 1 min after pulsation. This response is strongly influenced by pulsing conditions and is independent of the total permeabilization achieved by the pulse. Our results, supported by similar measurements on osmotically dehydrated control samples, clearly show that PEF causes a rapid change of the viscoelastic properties of the tissue that could be attributed to a partial loss in turgor pressure. This would be an expected consequence of electroporation. The recovery of tan-δ to values similar to those before pulsation strongly suggests recovery of cell membrane properties and turgor, pointing at reversible permeabilization of the cells. A slight increase of stiffness traduced by a negative change of tan-δ after application of certain PEF conditions may also give an indication of events occurring on cell wall structure due to stress responses. This study set the basis for further investigations on the complex cell stress physiology involving both cell membrane functional properties and cell wall structure that would influence tissue physical properties upon PEF application.Fundação para a Ciência e a Tecnologia (FCT

Structure and evolution of the plant cation diffusion facilitator family of ion transporters

Peer reviewedPublisher PD