DESIGN AND PERFORMANCE STUDY OF A PERMANENT MAGNET FUEL SAVER

A fuel saver consisting of two permanent magnets has been designed. The magnetic field is supplied by NdFeB permanent magnets and is about 1.3 Tesla. The quantum theory is based on the well known Zeeman diagram of the 1s level of the hydrogen atom. The fuel saver is tested in a diesel car and its performance is reported and analyzed. We also describe the benefits of our mechanism on environment and equipment life time and present its diverse applications

Computational insight on magnetic skyrmions existence in Pt/CoFeB/Ru/CoFeB nanodisks

[EN]Nanometric spin structures such as skyrmions are covering a large area of applications related to new technologies. In this paper, we carry out a computational study on magnetic skyrmions behavior in Pt/CoFeB/Ru/CoFeB antiferromagnetic-exchange coupled systems. We aim to explore the possibilities of skyrmions nucleation in such multilayer. We demonstrated that skyrmions could be hosted in such system under specific conditions. We also studied the in-plane and out-of-plane reversal magnetization processes for these magnetic multilayers in order to check the skyrmion behavior under magnetic field loops.Publicación en abierto financiada por la Universidad de Salamanca como participante en el Acuerdo Transformativo CRUE-CSIC con Elsevier, 2021-202

Intermolecular interactions effects on magnetization tunnelling in molecular magnets

Using a pure quantum calculations and magnons approach, we investigated the magnetic properties of SMMs with crystal-field anisotropy. Our analysis introduces a clear physical mechanism for the appearance of the magnetic plateaus in the system which is related to tunnel and relaxation magnetization effects. We consider two cases of interest: when the SMM are completely independent and when there are inter-cluster magnetic couplings, especially super exchange and dipolar interactions. In such case, we give a special attention to single-ion anisotropies and dipole-dipole interactions. The dispersion relations and magnetization behaviours are explored and analyzed in the quantum magnons formalism taking into account the experimental reality and using commonly parameters values.Using a pure quantum calculations and magnons approach, we investigated the magnetic properties of SMMs with crystal-field anisotropy. Our analysis introduces a clear physical mechanism for the appearance of the magnetic plateaus in the system which is related to tunnel and relaxation magnetization effects. We consider two cases of interest: when the SMM are completely independent and when there are inter-cluster magnetic couplings, especially super exchange and dipolar interactions. In such case, we give a special attention to single-ion anisotropies and dipole-dipole interactions. The dispersion relations and magnetization behaviours are explored and analyzed in the quantum magnons formalism taking into account the experimental reality and using commonly parameters values

Identification of viscoelastic material properties based on Big Bang-Big Crunch optimization method

An efficient identification method of the dynamic properties of viscoelastic damping materials using an optimization technique is proposed. A Zener fractional derivative model is used to describe the frequency-dependent dynamic characteristics of materials. In this study, the viscoelastic material is used in a Passive Constrained Layer Damping (PCLD) configuration in order to increase the shear deformation in the material. Mean Square Velocities (MSVs) of a clamped-free beam covered with a PCLD patch are measured in an environmental chamber at different frequencies and used as reference MSVs. The excitation force is performed thinks to a low mass magnet fixed on the beam and placed inside a coil subjected to an electrical current. Numerical MSVs are calculated using an equivalent single layer plate model with warping functions chosen to ensure continuity of transverse shear stresses and displacements layer's interfaces

Advantages and Limitations of Using FTIR Spectroscopy for Assessing the Maturity of Sewage Sludge and Olive Oil Waste Co-composts

Composts prepared using different solid and liquid organic wastes from various sources can be used as growing media when these materials present adequate proprieties for plant development. The stability and maturity are among the main characteristics of composts. The purpose of this study is to recommend specific bands of the IR spectrum recorded on different composts to enable qualitative and rapid monitoring of the stages of biodegradation during composting. At the beginning of humification, the significant decrease in the intensity of the band located at 1735 cm–1 shows that lignin is affected at the first stage of the composting process. At the end of the humification, the band located toward 3450–3420 cm–1 at the beginning of the process undergoes a systematic shift (Δν of the order of 10 cm–1) toward lower wave numbers. The band located at 1660–1650 cm–1 on the Fourier transform infrared spectroscopy (FTIR) spectra before composting shifts systematically toward 1640 cm–1 at the end of humification. This phenomenon can be used as index of compost maturity. Measuring the band at 1035 cm–1 as an internal standard, it is possible to quantify the degradation rate of organic matter

13C NMR study of the effect of aerobic treatment of olive mill wastewater (OMW) on its lipid-free content

Olive mill wastewater was treated by an aerobic bio-process at different values of pH (with or without addition of lime), for 45 days on a laboratory scale, to evaluate the reduction of the organic load. The lipid content showed an appreciable change in relation to the applied treatment both for total lipids and for the different fractions (neutral lipids, monoglycerides and phospholipids). 13C NMR spectroscopy was performed on initial and final samples both raw and after lipid extraction. The main spectral differences were observed in the C-alkyl region (0–50 ppm), in the C O-alkyl/N-alkyl region (50–110 ppm), and in the C-carboxylic (160–200 ppm) region, providing information on the alterations occurring in the different biochemical entities composing this complex biomatrix (e.g. lipids and carbohydrates) according to the treatment

Fate of phthalic acid esters during composting of both lagooning and activated sludges

Among the phthalic acid esters (PAEs) targeted by the United States Environmental Protection Agency (USEPA) as priority pollutants, di-ethyl-hexyl phthalate (DEHP) is the major pollutant identified at high concentration level in lagooning sludge (LS), at about 28.67 mg/kg, andin activated sludge (AS), at about 6.26 mg/kg. Other phthalic acid esters, such as di-butyl phthalate (DBP) and di-methyl phthalate (DMP) show very low concentrations. During sludge composting, after the stabilization phase, the subsequent appearance of DEP and then DMPoccurred indicating that microbial metabolism begins by alkyl side-chain degradation before aromatic ring-cleavage. The appearance andaccumulation of PAEs with a short alkyl side-chain in the last stages of AS and LS composting is suggested originating from the degradationof phthalates with a much long side-chain. The DEHP showed a rate of biodegradation that follows a first-order kinetic model during composting of both AS and LS. The calculated DEHP half-lives are 45.4 days for LS and 28.9 days for AS. The better DEHP biodegradationrate (2.4 Â 10À2 dayÀ1) have been observed in the case of AS composting compared to LS compost (1.53 Â 10À2 dayÀ1). The mono-ethyl-hexyl phthalates MEHP has been shown to follow the same order of biodegradation as DEHP indicating that the same mechanism is followed(hydrolysis or dealkylation of each DEHP side-chain). Composting could be suggested as a detoxification process for the removal of PAEs(mainly DEHP) from sludges after a sufficient time of treatment to provide a safe end product

Chemical and spectroscopic analysis of olive mill waste water during a biological treatment

The treatment of olive mill waste water was studied on the laboratory scale. Physico–chemical analyses showed the final products had a mean pH of 5.4 without neutralisation and 5.7 when lime was added to the process. Raising the pH by adding lime had a positive outcome on the degradation of phenols, whose levels were reduced by over 76%. The lime also changed the structure of the organic matter, as seen in the infra-red spectra. Combining the FT-IR and 13C NMR data showed that with addition of lime, the density of aliphatic groups decreased to the benefit of aromatic groups, indicating that polymerisation of the organic matter occurred during the bioprocess. Under our experimental conditions, the biotransformation of olive mill waste water appears to favour the stabilisation of the organic matter through mechanisms analogous to those that lead to the formation of humus in the soil