Model and Design of a Power Driver for Piezoelectric Stack Actuators

A power driver has been developed to control piezoelectric stack actuators used in automotive application. An FEM model of the actuator has been implemented starting from experimental characterization of the stack and mechanical and piezoelectric parameters. Experimental results are reported to show a correct piezoelectric actuator driving method and the possibility to obtain a sensorless positioning control

Performance of tiles composed of blast furnace slag and vegetable fiber in prototype barns

Busca-se, em todo o mundo, a substituição do cimento amianto por alternativas seguras para o ambiente e para a saúde do trabalhador, além de econômicas, razão por que o uso de fibras vegetais como aglomerado em países tropicais onde estes resíduos são abundantes, tem-se mostrado bastante viável. No presente experimento foram comparadas telhas de cimento amianto pintadas com tinta reflexiva, telhas cerâmicas e telhas compostas de uma matriz à base de cimento Portland CPII 32Z (ABNT NBR-5735), escória de alto-forno (EAF) e sílica ativa, reforçadas com fibras de polpa celulósica de sisal (Agave sisalana). Utilizaram-se protótipos de galpões avícolas nos quais o calor produzido pelas aves foi simulado por lâmpadas incandescentes. Para caracterização do ambiente térmico lançou-se mão dos índices de conforto: ITU (índice de temperatura e umidade), ITGU (índice de temperatura de globo e umidade), CTR (carga térmica radiante) e entalpia (H) em que os resultados demonstraram que as telhas compostas apresentaram comportamento térmico semelhante ao das telhas cerâmicas, podendo ser utilizadas em substituição às telhas de cimento amianto.The substitution of cement asbestos by safer and equally economical alternatives has being searched for throughout the world. The usage of vegetal staple fiber as agglomerate in tropical countries where these residues are abundant has shown it self to be viable. In this study, roofing tiles fabricated with cement base Portland CPII 32Z (ABNT NBR-5735), blast furnace slag (EAF), active silica reinforced with cellulose pulp staple fibers of sisal (Agave sisalana) were compared with cement asbestos roofing tiles with white paint and ceramic roofing tiles. Prototypes of poultry facilities were used and lamps simulated the heat produced by the birds. Indices ITU, ITGU, CTR and entalpy (H) were employed for the characterization of the thermal atmospheric comfort and the results showed that the alternative roofing tiles were similar to the ceramic tiles and could be used as a substitute for asbestos roofing tiles

Effects of Eucalyptus pulp refining on the performance and durability of fibre-cement composites

Although Eucalyptus pulp has been widely used in the paper industry, there is limited information concerning its use as reinforcement in fibre-cement composites. The objective of this study was to evaluate effects of mechanical treatment (refining) of the Eucalyptus pulp on fibre properties as well as performance and microstructure of fibre-cement composites. The composites were evaluated before and after accelerated ageing cycles. The refining increased the capacity of Eucalyptus fibres to capture mineral particles, improving the adherence of the fibres with the matrix. This improved fibre-matrix interface led to better mechanical properties at 28 days of cure but higher mineralisation of fibres and consequently increased brittleness of composites after accelerated ageing (soak and dry) cycles. Unrefined fibres maintained the toughness of composites after ageing cycles. This indicates that refining may weaken the fibres thus affecting the mechanical performance (mainly decreasing modulus of rupture and toughness) of composites after ageing cycles. These results are useful for understanding effects of refined fibre conditions (morphology, mechanical strength and surface properties) on mechanisms of fibre-matrix adherence, fibre mineralisation and degradation of fibre-cement composites.FAPESP (05/59072-4, 07/05299-3)FAPEMIGCAPESCNP

Open mirror symmetry for Pfaffian Calabi-Yau 3-folds

We investigate the open mirror symmetry of certain non-complete intersection Calabi- Yau 3-folds, so called pfaffian Calabi-Yau. We perform the prediction of the number of disk invariants of several examples by using the direct integration method proposed recently and the open mirror symmetry. We treat several pfaffian Calabi-Yau 3-folds in $\mathbb{P}^6$ and branes with two discrete vacua. Some models have the two special points in its moduli space, around both of which we can consider different A-model mirror partners. We compute disc invariants for both cases. This study is the first application of the open mirror symmetry to the compact non-complete intersections in toric variety.Comment: 64 pages; v2: typos corrected, minor changes, references added; v3: published version, minor corrections and improvement

Emx2 is a dose-dependent negative regulator of Sox2 telencephalic enhancers.

The transcription factor Sox2 is essential for neural stem cells (NSC) maintenance in the hippocampus and in vitro. The transcription factor Emx2 is also critical for hippocampal development and NSC self-renewal. Searching for 'modifier' genes affecting the Sox2 deficiency phenotype in mouse, we observed that loss of one Emx2 allele substantially increased the telencephalic β-geo (LacZ) expression of a transgene driven by the 5' or 3' Sox2 enhancer. Reciprocally, Emx2 overexpression in NSC cultures inhibited the activity of the same transgene. In vivo, loss of one Emx2 allele increased Sox2 levels in the medial telencephalic wall, including the hippocampal primordium. In hypomorphic Sox2 mutants, retaining a single 'weak' Sox2 allele, Emx2 deficiency substantially rescued hippocampal radial glia stem cells and neurogenesis, indicating that Emx2 functionally interacts with Sox2 at the stem cell level. Electrophoresis mobility shift assays and transfection indicated that Emx2 represses the activities of both Sox2 enhancers. Emx2 bound to overlapping Emx2/POU-binding sites, preventing binding of the POU transcriptional activator Brn2. Additionally, Emx2 directly interacted with Brn2 without binding to DNA. These data imply that Emx2 may perform part of its functions by negatively modulating Sox2 in specific brain areas, thus controlling important aspects of NSC function in development

Expanding the Enzymatic Toolbox for Carboligation: Increasing the Diversity of the ‘Split’ Transketolase Sequence Space

Transketolases (TKs) are thiamine diphosphate (ThDP)-dependent enzymes that catalyze the transfer of two-carbon units in a stereoselective manner, making them valuable biocatalysts for sustainable processes. Most known TKs are about 650 amino acids long; however, a second type found in Archaea and many Bacteria consists of two proteins, each of about 300 amino acids. Exploring the unique features and differences of split TKs may help in assessing their potential use in biocatalysis and for uncovering new reactivities. Additionally, it could provide valuable information on how their structure relates to their function, especially compared to full-length TKs. In this study, we significantly expanded the known repertoire of split TKs approximately 14-fold to the best of our knowledge, by identifying and providing accessions of nearly 500 putative split-TK subunit pairs. Moreover, we doubled the number of experimentally produced and tested split TKs by cloning, purifying, and testing ten candidates retrieved from genomes and in-house metagenomes. Interestingly, pQR2809 and pQR2812, derived from hyperthermophilic organisms, showed enhanced thermostability compared to other TK examples in the literature, maintaining partial activity after heating at 90 °C or 100 °C for 1 hour, respectively

A Method for Battery Sizing in Parallel P4 Mild Hybrid Electric Vehicles

This article deals with a sensitivity analysis concerning the influence that the capacity of the battery in a parallel hybrid powertrain has on the vehicle's energy regeneration. The architecture under analysis is constituted by an internal combustion engine (ICE), which provides traction to the front axle's wheels, and an electric motor powering the rear wheels. The energy management system (EMS) is based on a simple torque split strategy that distributes the driver's required torque between the front and rear machines as a function of battery and electric motor functional limitations (state of charge, temperatures, and maximum admissible currents). Together with the selected driving cycles, the central role played by the battery size in the overall vehicle recoverable energy is evaluated, while the influence of the powertrain limitations is highlighted, accounting both for uncertain parameters (e.g., initial state of charge [SoC 0]) and for tunable parameters (e.g., maximum electric traction vehicle speed). Therefore, a method of sizing the battery of a P4 mild hybrid electric vehicle (HEV), which allows the maximization of the braking energy recovery, is developed

Predictive handling limits monitoring and agility improvement with torque vectoring on a rear in-wheel drive electric vehicle

This work presents a predictive torque vectoring controller that optimally monitors the vehicle limits of handling using active torque distribution in the rear axle of a fully electric vehicle. It works in combination with a feedforward controller designed to improve the vehicle's agility. The overall torque vectoring strategy is described together with the vehicle lateral dynamics, sideslip angle estimator, and torque allocation method. Numerical simulations for various scenarios and road profiles show the benefits of predicting the vehicle's handling limits and the enhancement of vehicle stability in terms of reduced vehicle sideslip angle and driver effort. The proposed optimal control method for predicting vehicle handling limit violations does not require a dedicated solver, making it a promising candidate for real-time applications. The case study is a vehicle equipped with two rear in-wheel motors in the framework of HiPERFORM, an ECSEL Joint Undertaking (JU) European research project. Hardware-in-the-loop (HiL) tests were performed on a dedicated e-axle test bench to integrate the torque vectoring controller with the real e-motors and a dual inverter. The results of the HiL testing demonstrate that the torque-vectoring requirements are satisfied by the hardware configuration in use