Estudio bibliográfico del estado del arte de la digestión anaerobia de residuos sólidos orgánicos y mejora del proceso mediante pretratamientos

El objetivo de este trabajo es realizar un estudio bibliográfico sobre el estado del arte de la digestión anaerobia de residuos sólidos orgánicos, comenzando con su definición y una clasificación general. A continuación, se justifica la necesidad de tratar estos residuos, así como su posibilidad de convertirlos en un recurso mediante el proceso de digestión anaerobia. Este proceso supone una oportunidad ambiental y tecnológicamente atrayente derivada del uso del biogás como energía renovable. La metodología abordada en este estudio se basa en la búsqueda y organización de la información, así como en los criterios de selección bibliográfica que se ajusten de forma explícita al tema tratado. Por otro lado, se ha analizado el proceso de digestión anaerobia explicando sus fases, las principales bacterias involucradas, los parámetros que afectan y las tecnologías que pueden llevarse a cabo en este proceso con el consumo energético asociado. Finalmente, se efectúa un análisis comparativo de los métodos de pretratamientos, entre los que destacan los pretratamientos mecánicos, térmicos, químicos y termoquímicos y biológicos, que permiten mejorar el proceso de digestión anaerobia y obtener un mayor rendimiento energético.El presente documento contiene 34 páginas

Luminescent behavior of Zn(II) and Mn(II) halide derivatives of 4-phenyldinaphtho[2,1-d: 1′,2′-f][1,3,2]dioxaphosphepine 4-oxide and single-crystal X-ray structure determination of the ligand

The two enantiomers of chiral phosphonate 4-phenyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide, O=PPh(BINOL), were synthesized from the proper 1,1′-bi-2-naphtol (BINOL) enantiomer and characterized. The structure of the (S)-enantiomer was elucidated by means of single-crystal X-ray diffraction. The reaction with anhydrous ZnBr2 afforded complexes having the general formula [ZnBr2{O=PPh(BINOL)}2] that showed intense fluorescence centered in the near-UV region rationalized on the basis of TD-DFT calculations. The corresponding Mn(II) complexes with the general formula [MnX2{O=PPh(BINOL)}2] (X = Cl, Br) exhibited dual emission upon excitation with UV light, with the relative intensity of the bands dependent upon the choice of the halide. The highest energy transition is comparable with that of the Zn(II) complex, while the lowest energy emission falls in the red region of the spectrum and is characterized by lifetimes in the hundreds of microseconds range. Although the emission at lower energy can also be achieved by direct excitation of the metal center, the luminescence decay curves suggest that the band in the red range is possibly derived from BINOL-centered excited states populated by intersystem crossing

Further Insight into the Manganese(II) 2,2′-Bipyridine-1,1′-dioxide Homoleptic Complex: Single-Crystal X-ray Structure Determination of the Perchlorate Salt and DFT Calculations

The homoleptic cationic complex formed by reacting suitable manganese(II) salts with 2,2′-bipyridine-1,1′-dioxide (bipyO2) has been subjected to several studies in the past because of its peculiar absorption and electrochemical features. Here, the first single-crystal X-ray structure determination of a [Mn(bipyO2)3]2+ salt is reported, where the charge of the cation is balanced by perchlorate anions. The hydrated salt [Mn(bipyO2)3](ClO4)2 crystallizes in the monoclinic system (P21/n space group) and the asymmetric unit contains three cationic complexes and six perchlorate anions. The environment of the manganese(II) ions is best described as octahedral, with scarce variations among the three cations in the asymmetric unit. The bipyO2 ligands exhibit κ2 coordination mode, forming seven-membered metallacycles. The X-ray outcomes have been used as the starting point for DFT and TDDFT calculations, aimed to elucidate the charge transfer origin of the noticeable absorption in the visible range. The MLCT nature is confirmed by the hole and electron distributions associated with the spin-allowed transitions. DFT calculations on the related manganese(III) complex indicate that the geometry of [Mn(bipyO2)3]2+ changes only slightly upon oxidation, in agreement with the reversible electrochemical behaviour experimentally observed

Synthesis and photoluminescence of manganese(ii) naphtylphosphonic diamide complexes

Manganese(II) halide complexes with N,N,N’,N’‐tetramethyl‐P‐naphtalen‐2‐ylphosphonic diamide were synthesized from anhydrous MnX2 salts (X = Cl, Br, I) and characterized. Single‐crystal X‐ray diffraction revealed in all the cases slightly distorted tetrahedral geometry of the coordination sphere. The photoluminescence spectra showed the superimposition of a green emission, related to the 4T1(4G) → 6A1(6S) transition of Mn(II), with a band in the red range. Different possible attributions to the lowestenergy emission were taken into account. The emission spectra of the isolated products are dependent upon the nature of the halide and, in the case of X = Br, also upon the excitation wavelength

El modelo Flipped Learning aplicado a la materia de música en el cuarto curso de Educación Secundaria Obligatoria: una investigación-acción para la mejora de la práctica docente y del rendimiento académico del alumnado.

El presente trabajo es un estudio bajo la metodología de la investigación-acción cuyo eje fundamental es la implantación del modelo metodológico llamado Flipped Learning en la materia de música en el cuarto curso de Educación Secundaria Obligatoria y las mejoras que puede llegar a producir con respecto a la práctica docente en general y del rendimiento académico del alumnado en particular. Se establecen como bases del estudio, la actitud, la motivación y el interés del alumnado hacia la materia de música y hacia su propio aprendizaje; las ayudas que se prestan entre iguales y la posible personalización e individualización de las ayudas por parte del profesorado; la implicación de las familias en todo el proceso de enseñanza y aprendizaje; la autonomía e iniciativa personal del alumnado; la mejora de la práctica musical (instrumental y vocal) del alumnado y el rendimiento académico del alumnado en general. Además, se abordan temas como la satisfacción de todos los agentes que intervienen en el proceso, el cambio de rol que se produce dentro del aula, los medios didácticos empleados, su idoneidad, su duración, su naturaleza y el propio modelo Flipped Learning para conocer su efectividad.Departamento de Pedagogí

Informe sobre expediente de relevancia jurídica S/N, Consorcio Neshuya contra Proyecto Especial de Infraestructura de Transporte Nacional-Provías Nacional

El presente informe jurídico tiene por objeto revisar los principales problemas jurídicos que plantea el laudo derivado del tercer proceso arbitral seguido por el Consorcio Neshuya contra el Proyecto Especial de Infraestructura de Transporte Nacional - PROVÍAS NACIONAL del Ministerio de Transportes y Comunicaciones – MTC, el cual resolvió las divergencias surgidas entre dichas partes por la ejecución del Proyecto de Obra Pública “Rehabilitación y Mejoramiento de la Carretera Huánuco – Tingo María – Pucallpa, sector Aguaytía – Pucallpa, Tramo III: Neshuya – Pucallpa”. En ese orden de ideas, el informe aborda el marco normativo vigente al momento de surgidas las controversias y, a partir de ello, analiza si el pronunciamiento recogido en el laudo resulta adecuado. Cabe señalar que este expediente, a pesar de su relativa antigüedad, nos permite analizar, entre otros aspectos, el tratamiento de las materias arbitrables, especialmente lo referido a la potestad de la Contraloría General de la República para aprobar adicionales y el enriquecimiento sin causa; así como también, la ejecución de mayores metrados. Es así que la importancia del presente informe reside, precisamente, en que tales tópicos mantienen plena vigencia en la actualidad y, a pesar de las sucesivas modificaciones de la Ley de Contrataciones del Estado, su aplicación todavía resulta compleja y continúa siendo causa de controversias entre contratistas y el Estado. Finalmente, realizado el análisis correspondiente, se concluye que la decisión emitida por el Tribunal Arbitral fue correcta a la luz de la normativa aplicable

Luminescent heteroleptic copper(I) complexes with polydentate benzotriazolyl-based ligands

Bis(benzotriazol-1-yl)phenylmethane CHPh(btz)2 and tris(benzotriazol-1-yl)methane CH(btz)3 were used as N-donor ligands to prepare luminescent heteroleptic copper(I) complexes. [Cu{CHPh(btz)2}(PPh3)2][BF4] and [Cu{CHPh(btz)2}(DPEphos)][BF4] (DPEphos = bis[(2-diphenylphosphino)phenyl] ether) were obtained from the corresponding borohydride complexes [Cu(BH4)(PPh3)2] and [Cu(BH4)(DPEphos)] and tetrafluoroboric acid. [Cu{CH(btz)3}(PPh3)][BF4] and [Cu{CH(btz)3}(PiPr3)][BF4] were prepared from the acetonitrile complex [Cu(NCCH3)4][BF4]. The complexes exhibited bright yellow or orange emissions upon excitation with near UV and violet light. The photoluminescent properties were attributed to metal-to-ligand charge transfer transitions on the basis of experimental data and DFT calculation

Preparation, reactivity and photoluminescence of copper(I) borohydride complexes with bis[(2-diphenylphosphino)phenyl] ether as chelating ligand

Bis[(2-diphenylphosphino)phenyl] ether (DPEphos) was used as chelating ligand to prepare the corresponding borohydride complex [Cu(2–BH4)(DPEphos)], whose structure was ascertained spectroscopically and by means of X-ray diffraction. The spectroscopic assignments related to the coordinated borohydride were confirmed by preparing the isotopologue [Cu(2–BD4)(DPEphos)]. Reaction of [Cu(2–BH4)(DPEphos)] with triflic acid afforded the dimer [Cu2(–BH4)(DPEphos)2][OTf] (OTf = triflate). The borohydride complexes exhibited appreciable blue emission upon excitation with UV light at room temperature. [Cu(2–BH4)(DPEphos)] revealed to be a suitable precursor for the preparation of luminescent heteroleptic copper(I) complexes having general formula [Cu(N^N)(DPEphos)]+ (N^N = 1,10-phenantroline, 2,9-dimethyl-1,10-phenantroline, 2,2’-bypiridine, 4,4’-dimethyl-2,2’bipyridine)

Green phosphorescent Zn(II) halide complexes with N,N,N′,N′‐tetramethyl‐P‐indol‐1‐ylphosphonic diamide as ligand

Tetrahedral Zn(II) complexes having general formula [ZnX2{O=P(NMe2)2Ind}2] (X= Cl, Br, I, NCS) were isolated from the reaction between the indol-1-yl substituted phosphoramide N,N,N',N'-tetramethyl-P-indol-1-ylphosphonic diamide (O=P(NMe2)2Ind) and anhydrous Zn(II) precursors under mild conditions. The structures of the three halide derivatives were ascertained by single-crystal X-ray diffraction. The bromo- and iodo-derivatives revealed to be appreciably luminescent in the green region upon excitation with light below 300 nm, with emission bands centred between 520 and 530 nm. The large Stokes shifts and the excited state lifetimes in the milliseconds range indicate that triplet excited states are involved in the emission. TD-DFT calculations indicated that the transition responsible of the luminescence is ligand-centred (3LC)

Pentamethylcyclopentadienyl osmium complexes that contain diazoalkane, dioxygen and allenylidene ligands: preparation and reactivity

Diazoalkane complexes [Os(η5-C5Me5)(N2CAr1Ar2)(PPh3){P(OR)3}]BPh4 (1, 2) [R = Me (1), Et (2); Ar1 = Ar2 = Ph (a); Ar1 = Ph, Ar2 = p-tolyl (b); Ar1Ar2 = C12H8 (fluorenyl) (c)] were prepared by reacting bromo-compounds OsBr(η5-C5Me5)(PPh3){P(OR)3} with an excess of diazoalkane in ethanol. The treatment of diazoalkane complexes 1 and 2 with acetylene under mild conditions (1 atm, RT) led to dipolar (3 + 2) cycloaddition affording 3H-pyrazole derivatives [Os(η5-C5Me5)(η1-[upper bond 1 start]N[double bond, length as m-dash]NC(C12H8)CH[double bond, length as m-dash]C[upper bond 1 end]H)(PPh3){P(OR)3}]BPh4 (6, 7) [R = Me (6), Et (7)] whereas reactions with terminal alkynes R1C[triple bond, length as m-dash]CH (R1 = Ph, p-tolyl, COOMe) gave vinylidene derivatives [Os(η5-C5Me5){[double bond, length as m-dash]C[double bond, length as m-dash]C(H)R1}(PPh3){P(OR)3}]BPh4 (8b–d, 9b–d) [R = Me (8), Et (9); R1 = Ph (b), p-tolyl (c), COOMe (d)]. Exposure to air of dichloromethane solutions of complexes 1 and 2 produced dioxygen derivatives [Os(η5-C5Me5)(η2-O2)(PPh3){P(OR)3}]BPh4 (10, 11) [R = Me (10), Et (11)]. Allenylidene [Os][double bond, length as m-dash]C[double bond, length as m-dash]C[double bond, length as m-dash]CR1R2 (12–14) [R1 = R2 = Ph (12, 13); R1 = Ph, R2 = Me (14)], vinylvinylidene [Os][double bond, length as m-dash]C[double bond, length as m-dash]C(H)C(Ph)[double bond, length as m-dash]CH2 (15) and 3-hydroxyvinylidene [Os][double bond, length as m-dash]C[double bond, length as m-dash]C(H)C(H)R2(OH) (16, 17) [R2 = Ph (16), H (17)] derivatives were also prepared. The vinylidene complex [Os(η5-C5Me5)([double bond, length as m-dash]C[double bond, length as m-dash]CH2)(PPh3){P(OMe)3}]BPh4 (8a) reacted with PPh3 to afford the alkenylphosphonium derivative [Os(η5-C5Me5){η1-C(H)[double bond, length as m-dash]C(H)PPh3}(PPh3){P(OMe)3}]BPh4 (18) whereas vinylidene complexes 8 and 9 reacted with water leading to the hydrolysis of the alkyne and the formation of carbonyl complexes [Os(η5-C5Me5)(CO)(PPh3){P(OR)3}]BPh4 (19, 20). The complexes were characterised by spectroscopic data (IR and NMR) and by X-ray crystal structure determination of [Os(η5-C5Me5){[double bond, length as m-dash]C[double bond, length as m-dash]C(H)p-tolyl}(PPh3){P(OEt)3}]BPh4 (9c), [Os(η5-C5Me5)(η2-O2)(PPh3){P(OMe)3}]BPh4 (10) and [Os(η5-C5Me5)(CO)(PPh3){P(OMe)3}]BPh4 (19)