Academic literature on the topic 'Carbon(0) complexes'

Mononuclear cobalt(o) complexes containing olefin and trimethylphosphane ligands Co(olefin)(PMe3)3 (olefin = C2H4 (1), C3H6 (2), cyclopentene (3), trans-1,2-diphenylethene (4), tetrafluorobenzo-bicyclo-(2.2.2)-octadiene (5)), are obtained from CoCl2 by reaction with magnesium in the presence of the ligands or by substitution of 3 with olefin. X-ray crystal structure determinations of 4 and 5 show a distorted tetrahedral arrangement of ligands around the cobalt atom. Chemical and spectroscopic properties are consistent with a paramagnetic valence state of the compounds in solution. By reaction with carbon monoxide a dicobalt complex is formed, while azobenzene gives paramagnetic Co(N2Ph2)(PMe3)2.

This review summarizes experimental and theoretical studies of transition metal complexes with two types of novel metal-carbon bonds. One type features complexes with carbones CL2 as ligands, where the carbon(0) atom has two electron lone pairs which engage in double (σ and π) donation to the metal atom [M]⇇CL2. The second part of this review reports complexes which have a neutral carbon atom C as ligand. Carbido complexes with naked carbon atoms may be considered as endpoint of the series [M]-CR3 → [M]-CR2 → [M]-CR → [M]-C. This review includes some work on uranium and cerium complexes, but it does not present a complete coverage of actinide and lanthanide complexes with carbone or carbide ligands.

Quantum chemical studies show that there is a class of carbon compounds with the general formular CL2 where the carbon atom retains its four valence electrons as two lone pairs. The C-L bonds come from L → C donor-acceptor interactions where L is a strong σ-donor. Divalent C(0) compounds (carbones) are conceptually different from divalent C(II) compounds (carbenes) and tetravalent carbon compounds, but the bonding situation in a real molecule may be intermediate between the three archetypes. There are molecules like tetraaminoallenes which may be described in terms of two double bonds (R2N)2C=C=C(NR2)2 where the extraordinary donor strength of the dicoordinated carbon atom comes only to the fore through the interactions with protons and Lewis acids. They may be considered as "hidden divalent C(0) compounds". The donor strength of divalent C(0) molecules has been investigated by calculations of the binding energies with protons and with main-group Lewis acids and the bond dissociation energies (BDEs) of transition-metal complexes.

Photolysis of hexacarbonyl-chromium(0), -molybdenum(0), and -tungsten(0) in presence of fumaronitrile yields at room temperature pentacarbonyl-fumaronitrile-chromium(0) (1), - molybdenum(0) (2), and -tungsten(0) (3). The complexes were purified by crystallization and characterized by IR and 13C-NMR spectroscopy. The fumaronitrile ligand is bonded to the M(CO)5 moiety by one nitrile nitrogen atom rather than by the carbon-carbon double bond. In toluene 2 dissociates into fumaronitrile and pentacarbonyl-molybdenum(0), which is stabi­lized by the solvent. Fumaronitrile and solvated pentacarbonyl-molybdenum(0) exist in solu­tion together with 2 in an equilibrium which lies in favour of the former species.

Photolysis of hexacarbonyl metal(0) or tetracarbonyl-bis(1,3-butadiene)metal(0) (metal: chromium, molybdenum, tungsten) in the presence of tetracyanoethylene, TCNE, or fumaronitrile , FN, at room temperature yields fram-bis(μ2-tetracyano-ethylene)tetracarbonyl-chromium(0) (1), -molybdenum(0) (2), -tungsten(0) (3) and trans-bis(fumaronitrile)tetracarbonylchromium(0) (4), -tungsten(0) (5) complexes. The complexes were purified by chromatography and recrystallization and characterized by IR , 1H, 13C NMR and mass spectroscopies. It is shown that two tetracyanoethylene ligands are symmetrically bonded to the M(CO)4 moiety through their carbon-carbon double bond in the form of μ2 -TCNE . The two fumaronitrile ligands are bonded to the central atom through their nitrogen atoms. The spectral data are discussed in terms of metal → ligand π - interaction.

Pentacarbonyl(η2-tetracyanoethylene) metal(0) complexes of chromium, molybdenum and tung­sten have been synthesized by the photochemical reaction of hexacarbonyl metal(o) with tetra- cyanoethylene in toluene at room temperature. The complexes were purified by chromatography and recrystallization, and characterized by UV- visible, IR and 13C NMR spectroscopy. Tetra- cyanoethylene is symmetrically bonded to the M(CO)5 unit through its carbon-carbon double bond as an η2-ligand. The spectral data are dis­cussed in terms of the metal → ligand π inter­action.

Les bis-ylures sont des espèces carbonées divalentes dans lesquelles un atome de carbone central porte deux charges négatives, chacune d’elles étant stabilisée par un hétéroatome chargé positivement en α du carbone. Transférer sélectivement l’atome de carbone central en se servant des deux fonctions ylures simultanément représente un grand intérêt pour les chimistes de synthèse. De telles sources atomiques de carbone restent toutefois rares, le carbone de la plupart des bis-ylures développés jusqu’à présent étant trop étroitement liées avec les deux ligands adjacent. Dans ce contexte, cette thèse se concentre sur le développement de bis-ylures et autres espèces réactives comprenant un ligand iodonium, fragment d’une extrême labilité qui permettrait une libération efficace du carbone central. Le premier chapitre est consacré à l’état de l’art des composés « carbone(0) » et à leur application en tant que source de carbone atomique, ainsi qu’à la structure et la réactivité de composés iodés hypervalents. Un second chapitre traite du relargage de bis-ylures après la rupture d’une liaison covalente, soit une liaison P–C d’ylures mixtes de phospho-iodonium stabilisés par une phosphine oxydée, soit une liaison Si–C d’ylures mixtes de phospho-iodonium stabilisés par un silane. Le troisième chapitre reporte nos tentatives d’obtenir des précurseurs de bis-ylures d’iodonium par iodation direct d’ylures de phosphonium ou de sulfoxonium nucléophiles. Le dernier chapitre concerne notre tentative de développer un yldiure d’iodonium, espèce pour laquelle seule une des deux charges négatives portées par le carbone est adjacente à un atome chargé positivement, l’autre n’étant stabilisé que par les effets inductifs et mésomères d’un groupement sulfonyle électroattracteur. Les résultats de ces tentatives nous ont permis d’identifier un nouvel ylure d’iodonium mono-stabilisé nucléophile, dont la réactivité avec des aldéhydes est décrite en fin de chapitre
Bis ylides are divalent carbonated s pecies on which a central carbon atom bears two negative charges, both stabilized by two α, positively charged heteroatoms. Selectively transferring the central carbon atom, using both ylides simultaneously is of great interest for synthetic chemists. Such atomic carbon sources are scarce, as most of the bis ylides developed until now were too tightly bind to his ligands. With this in mind, this thesis ambitions to develop bis ylides and other reactive species containing an iodonium ligand, an extremely labile fragment which could allowed an efficient liberation of the central carbon atom. The first chapter is dedicated to the state of the art of “carbon(0)” compounds and their application as atomic carbon sources, as well as the structure and reactivity of hypervalent iodine compounds. The second chapter is about releasing bis ylides by cleaving a covalent bond, either a P C bond from a phosphine oxide stabilized mixt phospho iodonium ylide, or a Si C bond from a silane stabilized mixt phospho iodonium ylide. A third chapter explains our attempts to obtain bis ylides precursor by direct iodination of nucleophilic phosphonium or sulfoxonium ylides. The last chapter is dedicated to our attempt to develop an iodonium yldiide, in which only one of the two negative charges borne by the central carbon is next to a positively charged heteroatom, the other being stabilized by a sulfonyl mesomeric and inductive effects. The results of those attempts allowed us to describe the reactivity of a new nucleophilic, mono stabilized iodonium ylide towards aldehydes

Formation of carbon–fluorine and carbon–fluoroalkyl bonds via transition metal complexes represents an efficient synthetic route towards a wide array of valuable fluorinated organic compounds and fluorinated metallacycles offer a potentially green and atom economical pathway towards these functionalized fluorocarbons. This thesis is focused on cycloaddition reactions of Ni=CF2 complexes with fluoroalkenes (FAs) and acetylenes. Cycloaddition reactions of the FAs vinylidene fluoride (CF2=CH2) and perfluoro(methyl vinyl ether) [CF2=CF(OCF3)] with the electron-rich Ni(0) fluorocarbene, Ni=CF2[P(OMe)3](dppe) affords stable metallacyclobutane complexes, likely through a 1,4-diradical mechanism previously investigated for analogous reactions using computational chemistry. With CF2=CHF (TrFE), however, the observed products are the C3 alkene E-CHF=CF(CF3) and the metallacyclopentane complex, Ni(C4H2F6)(dppe), derived from oxidative coupling of two additional equivalents of TrFE. It is proposed that the instability of the initially formed metallacyclobutane gives rise to a 2,1-F shift, yielding the C3 alkene complex. Reaction of the latter with excess TrFE then liberates the C3 alkene, forming the TrFE alkene complex followed by the observed metallacyclopentane product. In the reaction of 1a with chlorotrifluoroethylene (CF2=CFCl) a single regioisomer of the metallacyclobutane is observed, but reacts further in THF solvent via α-Cl migration to Ni, affording the tetrafluoroallyl complex, NiCl(CF2CF=CFH), in which one F has been replaced by a hydrogen. Finally, reaction of 1a with hexafluoropropene [CF2=CF(CF3), HFP] takes an unprecedented turn, affording the Ni trifluoromethyl perfluoroalkenyl complex from formal transfer of one F from HFP to the Ni=CF2 moiety. The capability of 1a to perform cycloaddition with a broader substrate scope was investigating by reacting it with terminal aryl-acetylenes of varying electronic parameters. Reaction of 1a with 1.5 equivalents of 4-R-phenylacetylene afforded the expected difluorometallacyclobutenes (R = H, Cl, tBu). Further observation revealed a second acetylene insertion to yield a nickelacyclohexadiene in the first example of a 4- to 6-membered ring expansion of perfluorometallacycles. The six-membered metallacycle then undergoes reductive elimination to furnish a difluorocyclopentadiene. The electronic parameters of the aryl-acetylene substrate play a dramatic role in the selectivity of product formation. The more electron-donating substrates 4-tert-butylphenylacetylene and 1-hexyne stabilize the metallacyclobutene, while the electron-withdrawing 4-chlorophenylacetylene affords a more reactive metallacyclobutene making it more prone to the second acetylene insertion. Phenylacetylene represented a middle-ground between the two systems and proved effective for further characterization studies. The electronic effect of the surrounding ancillary ligand system was also studied by substituting dppe in 1a for P(OMe)3 and dipe to give analogous Ni(0) difluorocarbene complexes 1b and 1c (dipe = 1,2-bis(diisobutylphosphino)ethane). The -acidic phosphite ligands in 1b gave exclusively nickelacyclohexadiene and difluorinated cyclopentadiene due to a reactive metallacyclobutene, whereas the more electron rich 1c formed the metallacyclobutene product almost exclusively. The results presented here will allow for future investigations of fluorinated metallacycle reactivity, increasing our ability to prepare value-added fluorocarbon products for pharma, agrochemicals, and polymer applications.

The synthesis and structure elucidation of fourteen novel Fischer ethoxy- and amino carbene complexes of molybdenum and chromium metals of the type [(CO)3L2M=C(X)R] were performed. Substitution of the parent pentacarbonyl complex [(CO)5M-C(OEt)(R)]; M = Mo, Cr; R = 2-thienyl, 2-furyl; with mono- and bidentate phosphine ligands yielded the corresponding tetracarbonyl complexes [(CO)4(PR’3)M-C(OEt)R] with M = Mo, Cr, R = 2-thienyl, 2-furyl and R’ = Ph, Cy or tricarbonyl complexes [(CO)3(DPPE)Mo-C(OEt)(2-furyl)], respectively. Aminolysis of these novel complexes resulted in substitution of the ethoxy substituent with an amino group. Full characterisation of these novel complexes included infrared spectroscopy, NMR (1H, 13C, 31P) spectroscopy, x-ray crystallography and mass spectral analyses. From the characterisation data, it was found that the cis isomer was dominant for the tetracarbonyl carbene complexes whereas the mer isomer was favoured in most cases for the tricarbonyl carbene complexes. Structural elucidation of nine of the novel complexes was confirmed with x-ray crystallography. The amino carbene complexes showed preference for a syn conformation of the oxygen atom of the furyl moiety and the nitrogen atom of the amino moiety in the crystal form. The ethoxy carbene complexes showed a preference for the anti conformation in the crystal form. The NMR analysis showed that resonance between the metal-carbene carbon-heteroatom stabilisation is more prevalent in the case of the amino carbene complexes. DFT calculations were performed for eleven of these complexes and their isomers. The infrared stretching modes were calculated and compared to experimental data. The HOMO and LUMO position and energy gaps were calculated. It was observed that the HOMO in all calculated complexes lay on the metal centre, while the LUMO was centred on the carbene carbon. It was found that the HOMO-LUMO gap was larger for the amino Fischer carbene complexes than for the ethoxy Fischer carbene complexes. From frontier orbital considerations, it is concluded that ligand substitution of carbonyls by phosphines as well as carbene substituent alterations does not seem to improve the reactivity of the novel complexes of this study particularly for the potential application as metathesis catalysts. The performed DFT calculations, in the future, can help determine which type of catalytic reactions these fourteen complexes would be most effective for.
Dissertation (MSc)--University of Pretoria, 2014.
tm2015
Chemistry
MSc
Unrestricted

The central focus of this study was the synthesis, structural investigation and characterisation of multiple chromium carbene complexes. Fifteen novel chromium(0) complexes were synthesised. The synthesis of the primary monocarbene starting material [Cr(CO)5{C(OEt)(heteroaryl)}], heteroaryl = thiophene, furan, 2,2’-bithiophene, was carried out utilising typical Fischer methodology. A wide variation of spacer ligands were reacted to obtain different carbene substituents. The ligand substitution reaction between carbonyl ligands and the bidentate ligands followed the techniques proposed in literature and produced distinctive chelated monocarbene complexes with the resulting structure mer- [Cr(CO)3(dppe){carbene)}]. An extensive collection of more sophisticated monocarbene complexes was synthesised via modification pathways (aminolysis). Conversion of original ethoxy-bearing monocarbenes through aminolysis provided the corresponding amine analogues, possessing both novel structure and unique chemical reactivity. The aminolysis reactions involved different sized amino reagents; both ammonia and cyclohexyl amine (bulky, cyclic chair amines) were employed to produce derivatives of the monocarbene starting complexes. Lastly, the synthesis of unique N-heterocyclic carbene (NHC) complexes was envisaged. Synthesis of both the pentacarbonyl-bearing and phosphine-bearing NHC complexes was attempted utilising an adapted version of a methodology proposed in literature. The synthesis of chelate NHC complexes, however, proved difficult and the resulting products were not obtained. All Fischer and N-heterocyclic carbene complexes were characterised using infrared spectroscopy, nuclear magnetic resonance spectroscopy and mass spectrometry. In cases where single crystals were obtained, X-ray crystallography was used to confirm molecular structures. X-ray crystallographic studies indicated that carbonyl substitution reactions performed on monocarbene starting material, will favour the formation of the meridonial isomer in molecules where the carbene substituents are less bulky. Due to steric considerations, the substitution of labile carbonyl ligands in the trans position to the carbene moiety will be favoured. Density functional theory (DFT) calculations were performed on the complexes synthesised in this study. The results obtained indicated the favoured isomeric form to be facial in some cases whereas crystallographic data signified the meridonial isomer as the more stable product, irrespective of the bulkiness of the carbene substituents. Bond lengths, geometry and bond angles were all comparable to those of the single-crystal X-ray data. Single-point energy calculations show clearly that modelling methods provide good estimations of energetically favourable geometries, and accurate DFT calculations also predict the HOMO and LUMO orientations around the metal or ligand spheres. The majority of the structures provided by the computed model, illustrated that the 3d atomic orbitals of the metal contributed significantly to the HOMO, whereas the LUMO was mostly orientated around the carbene carbon atom. Metathesis and polymerisation catalytic reactions were attempted on [Cr(CO)3(dppe){C(OEt)(thiophene)}], 2, whereas only metathesis studies were employed for [Cr(CO)3(dppe){C(NHCy)(thiophene)}], 6. Both complexes presented as inert to either reaction and no catalytic capability was witnessed. Gas chromatography was used to indicate the level of progression of the reaction and the chromatogram verified that neither pre-catalyst found application in metathesis or, in the case of 2, in polymerisation.
Dissertation (MSc)--University of Pretoria, 2012.
Chemistry
MSc
Unrestricted

The synthesis of novel Fischer and N-heterocyclic tungsten(0) carbene complexes was endeavoured in this study and resulted in the synthesis, isolation and characterisation of eighteen new complexes. Sixteen novel Fischer carbene complexes were synthesised. In these complexes, both carbene ligand substituents were varied. Ethoxy as well as amino heteroatom substituents were used. Heteroaryl compounds thiophene and furan were employed as the second substituents on the carbene ligand. Complexes with combinations of these different substituents were synthesised and investigated to assess the influence the various substituents of the carbene ligand may have on the carbene complex itself. In addition, the metal ligand sphere was altered by substitution of one or two carbonyl ligands for either an amine or a phosphine ligand/s. These substitutions resulted in the formation of metal pentacarbonyl, metal tetracarbonyl as well as metal tricarbonyl systems. The complexes were successfully characterised by means of NMR and IR spectroscopy, and in selected cases X-ray diffraction and mass spectrometry. Synthesis of N-heterocyclic carbene complexes derived from isopropyl and mesityl imidazolium chlorides was attempted. The products were obtained in crude form, but could not be isolated due to decomposition during purification. Two novel decomposition products, which point towards a unique decomposition route, were isolated. Theoretical models of both the novel Fischer carbene complexes and the N-heterocyclic carbene complexes were calculated. This allowed for identification of infrared modes observed in experimental data. Furthermore, the HOMO and LUMO distributions and the HOMO-LUMO energy gaps were calculated, along with electrostatic potential maps. In all the Fischer carbene complexes the HOMOs were located on the metal centre and the LUMOs on the carbene ligand. In contrast, the HOMO and the LUMO were both located on the metal centre for the N-heterocyclic carbenes. The HOMO-LUMO energy gap decreased as follows: NHC complexes > Amino Fischer carbene complexes > Ethoxy Fischer carbene complexes Lastly, in all the complexes studied, the electrostatic potential maps indicated that the highest amount of electron density was found on the carbonyl ligands of these complexes. Both experimental and theoretical data indicated marked differences in the various classes of compounds, suggesting that these complexes would not only have different reactivities but also be suited to different applications. Experimental studies on reactivity and applications are thus future avenues of study which are made available from these results.
Dissertation (MSc)--University of Pretoria, 2012.
Chemistry
MSc
Unrestricted

Le but de ce travail est d'examiner la capacité des fonctionnelles M05-2X, M05-2X+D3, PBE0, PBE0+D3, PBE, PBE+D3 et M11 avec ou sans inclusion de la correction de dispersion de Grimme (D3) pour la description précise et simultanée des complexes organométalliques de taille moyenne et leur utilisation dans l’étude de la structure d’équilibre, la stabilité, la spectroscopie et la liaison chimique (covalente, transfert de charge et Van der Waals (vdWs). Ceci a été fait par une comparaison directe des résultats obtenus par ces fonctionnelles avec ou sans inclusion de la correction de dispersion de Grimme (D3) et ceux issus des méthodes explicitement corrélées (R)CCSD(T)-F12 et (R)MP2-F12. Nous avons démontré que les fonctionnelles M05-2X+D3 et PBE0+D3 en connection avec la base 6-311++G(d,p) sont les fonctionnelles de choix. Ceci a été illustré à travers une étude systématique des complexes Zn+qIm (q=0, 1,2) qui jouent un rôle important en chimie, en biologie, en environnement et en industrie. Pour les complexes Zn+qIm (q=0, 1, 2), nous avons comparé les résultats obtenus aux niveaux M05-2X, M05-2X+D3, PBE0, PBE0+D3, PBE, PBE+D3, M11 et ceux issus des méthodes explicitement corrélées (R)CCSD(T)-F12 et (R)MP2-F12. A travers ces comparaisons, nous avons établi que la capacité et la fiabilité de la fonctionnelle M05-2X(+D3) pour la décrire précisément les interactions covalentes et non-covalentes entre Znq+ et Im car elle donne des résultats en excellent accord avec ceux issus des méthodes ab initio hautement corrélées. Les fonctionnelles PBE0 et M11 peuvent être aussi utilisées pour les applications.Par la suite, nous allons profiter de la haute performance des fonctionnelles M05-2X et PBE0 avec ou sans inclusion de la correction de dispersion de Grimme (D3) en connection avec la base 6-311++G(d,p) pour étudier la structure d’équilibre, la stabilité, la spectroscopie et la liaison chimique (covalente, transfert de charge et van der Waals (vdWs) des complexes Znq+Imn (q = 0, 1, 2 ; n = 1–4). Ce travail à l’échelle microscopique, est utile pour comprendre la structure et la liaison se produisant dans les sites actifs contenant du zinc dans des systèmes biologiques (e.g. protéines). De plus, nos résultats peuvent être utilisés pour la détermination des champs de force précis pour les métalloprotéines ou les ZIFs.Les structures de type zéolithe–imidazole (Zeolitic–Imidazolate Frameworks ou ZIFs) sont composées de molécules organiques (e.g. molécules imidazoles) liées entre elles par des ions métalliques bivalents M+2 (e.g. M2+ = Zn+2/Co+2). Ces composés présentent une structure topologique bien stabilisée avec une large diversité de structure. Ils présentent ainsi une forte porosité qui est potentiellement utilisé dans la capture et le stockage du CO2 et dans son piégeage sélectif.Ces quantités au niveau microscopique sont nécessaires pour déduire les propriétés macroscopiques et thermochimiques de ces composés avec une bonne précision après incorporation dans des simulations dynamiques
The main goal of this work is to examine the capabilities of M05-2X, M05-2X+D3, PBE0, PBE0+D3, PBE, PBE+D3 and M11 functionals with and without inclusion of D3 dispersion correction for the accurate description of medium sized organometallic compounds and therefore their use for the determination of study of the equilibrium structure, the stability, the spectroscopy and the chemical bonding (covalent, charge transfer and van der Waals) of Znq+Im (q = 0,1,2) complexes. This is done through close comparisons of the results obtained by the M05-2X, M05-2X+D3, PBE0, PBE0+D3, PBE, PBE+D3, M11 functionals with and without inclusion of D3 dispersion correction and those from the standard ((R)MP2 and (R)CCSD(T)) and explicitly correlated ab initio methods (R)CCSD(T)-F12 and (R)MP2-F12. Therefore, we definitely establish that M05-2X+D3 and PBE0+D3 in connection with the 6-311++G(d,p) basis set are the methods of choice for the accurate description of medium sized organometallic compounds. This is illustrated through a systematic study of Zn+qIm of (q=0, 1, 2) complexes which play crucial roles in chemical, biological and industrial domains. Through these comparisons, we show that the results obtained at the M05-2X, M05-2X+D3, PBE0, PBE0+D3, PBE, PBE+D3, M11 levels are in good agreement with those explicitly correlated (R)MP2-F12 and (R)CCSD(T)-F12 methods. Through these comparisons, our study establishes the ability and reliability of M05-2X(+D3) functional for the accurate description of covalent and noncovalent interactions between Znq+ and Im since it leads to close agreement with the large ab initio techniques. PBE0 and M11 may be used also for that purposes. Then, we used high performance M05-2X and PBE0 functionals with and without inclusion of D3 dispersion correction in connection along with the 6-311++G(d,p) basis set to study the equilibrium structure, the stability, the spectroscopy and the chemical bonding (covalent, charge transfer and van der Waals) of Znq+Imn (q = 0, 1, 2, n = 1−4) complexes. This work, at the microscopic level, is useful for understanding the structural and bonding occurring in naturally zinc-binding sites and to figure out the behavior of much more complex biological systems. This should help for designing new zinc-binding proteins and more generally new metal sites in known proteins or ZIFs. The structural backbone of ZIFs is constructed from tetrahedral units formed by one bivalent metal ion (M2+ = Zn2+/Co2+) and four imidazolate anions. Such compounds present a well-established structural topology with a large structural diversity. They exhibit a high porosity which is potentially used for gas storage and separation techniques.Such quantities at the microscopic level are needed to deduce the macroscopic and thermochemical properties of these compounds with good accuracy after incorporation into dynamical simulations

The focus of this thesis is the synthesis of novel palladium(0) complexes bearing the ligand 1,3,4,5-tetramethylimidazol-2-ylidene (ITMe), a small percentage buried volume N-heterocyclic carbene. These complexes have been assessed as mediators for the 1,2-additions of hetero element-element bonds to unsaturated organic moieties. In particular, Si-Si, Si-B and B-B bond additions to alkynes and azobenzenes were chosen as reactions of interest due to their challenging nature. Chapter 1 introduces the concept of transition metal mediated element-element additions to alkynes and includes a thorough review on the current literature state. Chapter 2 describes the first solution based synthesis of [Pd(ITMe)2] and its in situ reactivity with Me3SiSiMe3 under mild conditions to form the novel complex cis-[Pd(ITMe)2(SiMe3)2], the first NHC-bearing complex resulting from the oxidative addition of hexamethyldisilane to a palladium centre. The use of this complex as a pre-catalyst for the bis(silyl)ation of electronically and sterically challenging internal acetylenes using non-activated disilanes is reported. A series of novel 1,2-disilylstilbenes were synthesized in high yield and with 100% Z-stereoselectivity. Chapter 3 details the use of [Pd(ITMe)2(PhC≡CPh)], the first bis(N-heterocyclic carbene)Pd(0)-alkyne complex, as a highly reactive pre-catalyst in the silaboration of terminal and internal alkynes to yield a number of known and novel 1-silyl-2-boryl alkenes. Unprecedented mild reaction temperatures for terminal alkynes, short reaction times and low catalytic loadings are reported. During mechanistic studies, cis-[Pd(ITMe)2(SiMe2Ph)(Bpin)] was directly synthesized by oxidative addition of PhMe2SiBpin to [Pd(ITMe)2(PhC≡CPh)]. This represents a very rare example of a (silyl)(boryl)palladium complex. A plausible catalyst decomposition route was also examined. In Chapter 4, [Pd(ITMe)2(PhC≡CPh)] acts as a highly reactive pre-catalyst in the unprecedented homogeneous catalyzed diboration of terminal and internal alkynes, yielding a number of novel and known syn-1,2-diborylalkenes in a 100% stereoselective manner. DFT calculations conducted by our collaborators suggest that a similar reaction pathway to that proposed for platinum phosphine analogues is followed, and that destabilization of key intermediates by ITMe is vital to the overall success for the palladium-catalyzed B-B addition to alkynes. Chapter 5 reports the use of [Pd(ITMe)2(PhC≡CPh)] as a highly active pre-catalyst in the diboration and silaboration of azobenzenes to synthesize a series of novel functionalized hydrazines. The reactions proceed using commercially available diboranes and silaboranes under mild reaction conditions. Preliminary investigations into further reactivity of [Pd(ITMe)2(PhC≡CPh)], [Pd(ITMe)2] and cis-[Pd(ITMe)2(SiR3)2] (SiR3 = SiMe2Ph or SiMe3) are reported in Chapter 6. This includes the oxidative cleavage of Me3GeGeMe3 by [Pd(ITMe)2(PhC≡CPh)] to form the novel cis-[Pd(ITMe)2(GeMe3)2] and an initial study into the catalytic alkyne digermylations. The hydrogenation of diphenylacetylene to form Z-stilbene using an amine-borane and catalytic quantities of [Pd(ITMe)2(PhC≡CPh)] was also investigated. Finally, the stoichiometric reactions of allyl bromides with cis-[Pd(ITMe)2(SiR3)2] to form the novel complexes trans-[Pd(ITMe)2(SiR3)(Br)] are detailed.

This thesis reports on the use of square planar nickel(II) complexes containing N-0 chelates as homogeneous catalyst precursors for carbon-carbon bond formation reactions. A series of new arylnickel phosphine complexes have been prepared. Complexes are of the type [NiR(N-0)L] [R = o-tolyl, N-0 = 2- pyridinecarboxylate pyca, L = PPh3 (la); R = o-tolyl, N-0 = p y c a, L = P(CH2Ph)3 (lb); R = o-tolyl, N-0 = pyca, L = PMePh2 (lc); R = o-tolyl, N-0 = PYca, L = PMe2Ph (1d); R = o-tolyl, N-0 = pyca, L = PCy3 (le); R = mesityl, NO = pyca, L = PMePh2 (10; R = phenyl, N-0 = pyca, L = PPh3 (lg); R = p-tolyl, N-0 = pyca, L = PPh3 (lh); R = mesityl, N-0 = 2-pyridineacetate pyac, L = PMePh2 (2a); R = o-tolyl, N-0 = 2-pyrazinecarboxylate pyzca, L = PPh3 (3a); R = o-tolyl, N-0 = pyzca, L = P(CH2Ph)3 (3b); R = o-tolyl, N-0 = 4-nitro-2- pyridinecarboxylate 4-NO 2-pyca, L = PPh3 (4a); R = o-tolyl, N-0 = 4-methoxy- 2-pyridinecarboxylate 4-Me0-pyca, L = PPh3 (5a)]. The complexes differ in the steric and electronic nature of the monodentate phosphine ligand, the size of the metallacycle (5-membered or 6-membered (2a)) and in the basicity of the N-0 -chelate. Crystal structure for the complexes [Ni(o-tolyl)pycaPPh3], [Ni(o-toly1)4- NO2 -pycaPPh3], [Ni(mesityl)pycaPMePh2] and [Ni(mesityl)p y a cPMePh2] indicate that the complexes have a square planar coordination with the phosphine ligand trans to the nitrogen atom. Upon warming, the complexes form moderately active single component catalysts for the oligomerisation of ethene. Products are 95-98% linear containing 60-80% a-olefins and show a geometric distribution of chain lengths. The effects of phosphine ligands, chelate ring size and chelate basicitS, on the catalytic performance have been studied. Catalyst activities and product distributions are highly dependant on the phosphine ligand present. Highest activities are obtained with complexes [Ni(o-tolyl)pycaPPh3 ] and [Ni(o-tolyl)pycaP(CH2Ph)31 and the highest percentage of linear a-olefins in the product is generated by [Ni(otolyl)pycaPMe2Ph]. Addition of excess PPh3 to the catalysts derived from [Ni(otolyl)pycaPPh3] provides mechanistic information on the oligomerisation process. The results are interpreted in terms of an associative insertion mechanism for the oligomerisation catalysts. The catalytic behaviour of the complexes vary greatly when the bidentate ligand is substituted in the 4-position of the pyridyl ring. It was found that complexes [Ni(o-toly1)4-NO2-pycaPPh3 ], [Ni(o-tolyl)pyzcaPPh 3 ] and [Ni(otoly1)4-Me0-pycaPPh 3 ] act as polymerisation catalysts and produce high molecular weight polyethylene. The possibility of two different insertion pathways being followed for the oligomerisation catalysts and the polymerisation catalysts may explain the different products obtained. Remarkably, the polymerisation catalysts are active for the copolymerisation of ethene with carbon monoxide and produce high molecular weight perfectly alternating polyketone. The complexes also form a moderately active catalytic system for the dimerisation of propene in the presence of alkyl aluminium co-catalysts such as A1Et2 C1 ' A1EtC1 2 and methylaluminoxane (MAO). The reaction has been examined as a function of catalyst, co-catalyst, and solvent. The activity and isomer distribution are shown to depend on the phosphine and bidentate ligands. The nature of the co-catalyst greatly affects the catalytic performance. The results are consistent with a bimetallic Ni-Al catalytic intermediate in equilibrium with excess co-catalyst.

碩士
國立彰化師範大學
化學系
99
The goal of this study is to design a series of active metal complexes for catalyzing various organic chemstry. During the last two decades, stable carbenes, especially N-heterocyclic carbene (NHCs), have been widely used as ligands for transition-metal complexes. Among their most appealing features is their strong -donor ability which can be superior to that of very basic phosphine. The monodentate palladium (0) and bidentate palladium (II) N-heterocyclic carbene complexes which bear amide functionalities have been successfully synthesized and were prepared from the amide-imidazolium salt. The series of palladium (0) complexes included two types of unsaturated N-heterocyclic carbene ligand precursors bearing amide moieties. Besides, the palladium (II) complexes contained bis-bidentate trans-configured isomer and chelating bidentate trans/cis isomers with pyridine-type ligand. All complexes are characterized by NMR analysis and their structural properties are determined by single-crystal X-ray crystallography. Through the study, it can be seen that the hereby palladium (0) complexes obtaining N-heterocyclic carbene and amide moieties with high electron donating property have a most salient advantage, which is able to catalyze with high efficiency in Suzuki-Miyaura、Mizoroki-Heck and direct arylation aryl-indolyl C-C coupling reactions. We also demonstrated using pentafluoroiodobenzene that the palladium (0) complex which contained a steric bulky mesityl functionality and a monodentate amide methyl-blocked moiety can proceed through oxidative addition pathway. This pathway leads to many interesting products and it is difficult to understand the mechanism and carry out the isolation. In this thesis, we resolve the problem by a preparative method such that a very interesting complex was successfully obtained and structurally characterized. Finally, the catalytic results show that the active palladim (0) complexes can deliver higher activities in the C-C coupling reactions under Suzuki、Heck and direct arylation reaction conditions.

碩士
國立彰化師範大學
化學系
100
Two series of potentially bidentate ligands bearing N-heterocycylic carbene and phosphine moieties were synthesized. For the phosphine moieties, two different substituents with different electronic and steric properties (PPh2 and PCy2) were employed. After successfully isolation of the ligand precusors, palladium(0) complexes bearing these ligands, 4a–i, were prepared. The complexes were characterized by 1H and 31P{NMR} spectroscopy, electron-spray mass spectrometry, elemental analysis as well as X-ray crystallography. Interestinly, the structures exhibit two different orientations for the coordinated maleic anhydride. Complex 4i shows a fluxional behavior in solution and the exchange process has been successfully investigated by theoretical computation. The catalytic properties of these new complexes were examined. Among them, 4a proved to be the most active in Mizoroki—Heck coupling reaction. The substrate scope was then investigated in detail. Palladium(0) complex was never employed as catalyst system in direct arylation raction. Herein, we showed that 4a is very promising in such non-traditional coupling reaction. Finally, we applied the technology of direct arylation to prepare a bitopic ligand, dipa, and successfully obtain some interesting cooridination polymers.

Com muita satisfação publicamos a obra intitulada “Gênero, raça, classe e o Direito: uma análise inclusiva”. Trata-se de uma obra que visa reunir pesquisas sobre estudos de gênero oriundas dos mais diversos pesquisadores de nosso país. Portanto, a presente obra traz temas muito interessantes e polêmicos, possuindo uma análise interseccional entre Gênero, Raça, Classe e Direitos Humanos. O primeiro capítulo intitulado “Diferenças de gênero na ciência e tecnologia: as questões de interseccionalidade a partir de experiências femininas” teve como objetivo principal estudar as mulheres na ciência, visto que a Ciência e Tecnologia (C&T) é um espaço de pesquisa e extensão de larga exploração desde o advento do capitalismo e por ter vinculação direta com as ciências da natureza, o ambiente ficou tradicionalmente conhecido como um espaço masculino devido a construção de um imaginário patriarcal. A estrutura das organizações não possibilita o êxito profissional do gênero feminino, o que nos possibilita afirmar que isso se deve mais pelas estruturas institucionais inapropriadas do que a falta de aptidão para as mulheres nas áreas da C&T. Nesse aspecto, ser uma mulher inserida na C&T é transgredir a cultura, afinal há uma diferença de gênero na área que resulta em silenciamentos, perseguições, preconceitos e dificuldades. O segundo capítulo intitulado “Violência de gênero: tecendo reflexões acerca da questão racial” visa aprofundar a temática da violência de gênero a partir do viés da interseccionalidade de gênero, raça e classe, os três eixos estruturantes que constituem a nossa sociedade. Não obstante, fruto de uma sociedade patriarcal, capitalista e racista em que a violência contra as mulheres atinge todas as classes sociais, raças e etnias, este trabalho se propõe analisar essas violações com ênfase nos dados estatísticos que mostram que as mulheres negras são as mais violadas no que se refere a violência doméstica. Para Heleieth Saffioti, os três eixos se fundem de maneira profunda e formam um “nó”. O patriarcado é o eixo mais antigo, logo, o racismo e o capitalismo encontram nele um terreno fértil para sua instalação e reprodução. Para além disso, busco trazer a reflexão dos avanços e limites legais na prevenção e enfrentamento à violência contra às mulheres, bem como busco atentar aos desafios profissionais presentes nos serviços de atendimento e os efeitos da pandemia de Covid-19. Para tal, foi realizada uma revisão e análise bibliográfica de livros, artigos, dossiês e leis. Além dessas fontes, foi utilizado vivências e experiências de estágio no Centro de Referência para Mulheres Suely Souza de Almeida (CRM-SSA). O terceiro capítulo intitulado “A representatividade da pessoa com deficiência física nas histórias em quadrinhos (HQs)” trata da importância da representatividade de pessoas com deficiência física no conteúdo das histórias em quadrinhos (HQS), contribuindo para a desconstrução de estereótipos existentes. Onde essas personagens através dos textos e das figuras oriundas do trabalho dos cartunistas grandes contribuintes auxiliam para informar, reduzir diferenças em qualquer faixa etária, ferramenta didática, auxilia na representatividade, visibilidade e inclusão. Apresentamos aqui através dessa pesquisa qualitativa, descritiva e bibliográfica apoiada na escrita um breve panorama das HQS e da deficiência, os tipos de deficiências e apresentamos as respectivas personagens com as mesmas características. O quarto capítulo intitulado “Assédio moral no serviço público estadual” tem como objetivo analisar um caso de assédio moral no trabalho ocorrido no âmbito da administração pública em Santa Catarina. As dificuldades e os desafios vivenciados pela vítima auxiliam a repensar acerca das possibilidades de prevenção, repressão e punição do assédio moral na esfera pública administrativa estadual, bem como a reparação de danos na justiça. Diante da análise do caso, observou-se que o assédio moral no trabalho é um fenômeno complexo, multidimensional, e que causa danos físicos e psicossociais, podendo acarretar incapacidade para o trabalho (aposentadoria precoce). Nesse contexto, pondera-se que os trabalhadores da administração pública, de regime estatutário, podem denunciar o assédio moral em duas esferas distintas, administrativa e justiça comum. O quinto capítulo intitulado “Biologia celular e molecular: a relevância do homossexualismo e seus componentes genéticos e biológicos” teve por objetivo realizar um levantamento bibliográfico sobre esta temática, tão atual na sociedade humana, abordando assim as contribuições genéticas e enfatizando os preconceitos da sociedade de forma ativa para os LGLBT (Lésbica, gays, bissexuais e transgêneros) A sexualidade é uma necessidade vital para vida do ser humano, desde a sua infância onde vem conhecer a sua higienização, a percepção do sexo masculino e feminino, características dos seus órgãos genitais e da necessidade que evidenciam cada um deles, até a vida adulta, onde tem sua vida sexual ativa. Porém, a sociedade de forma incoerente, de forma crítica e irrelevante, faz o julgamento da opção e determinação sexual, não considerando os fatores que afloram diante dos caracteres genéticos, fatores esses que agregam nos cromossomos, que vem do início de sua formação. O sexto capítulo intitulado “Morro da Gamela: a sacralidade ao longo do tempo” os autores dissertam que muitos crentes que peregrinam até o morro da gamela na atualidade pensando que a sacralidade do lugar seja algo iniciado pelos seguidores do cristianismo. Entretanto, de acordo com algumas publicações do periódico Diário da Manhã, tais cerimônias, bem como também a localidade, eram vistos por um segmento da sociedade capixaba da época como algo afrontoso. Na edição do dia 13 de maio de 1917 o Diário da Manhã publicou uma matéria que tinha como título: “Um antro de reuniões suspeitas” (figura 1), narrando uma ação policial realizada no Morro da Gamela. O sétimo capítulo intitulado “Contextualizando as atitudes dos profissionais da saúde em relação ao aborto legal” destaca que na maioria dos países desenvolvidos, o aborto é permitido para salvar a vida da gestante, resguardar a sua saúde física ou mental, quando a gravidez resultou de estupro ou incesto, em casos de anomalia fetal, por razões socioeconômicas e por requisição da mulher. Contudo, no Brasil, o aborto é ainda um tema polêmico que suscita discussões nas diversas áreas do conhecimento, notadamente entre os profissionais da área de saúde que realizam o procedimento. O objetivo geral do estudo é realizar uma análise da produção científica sobre as atitudes dos profissionais de saúde em relação ao aborto legal. O oitavo capítulo intitulado “Sistema prisional brasileiro: o processo de ressocialização de ex-detentas ao convívio social” tem como objetivo refletir sobre a realidade vivida pelas detentas nas prisões brasileiras e entender como o Sistema Prisional pode influenciar no processo de ressocialização de “ex-detentas”. Este capítulo objetiva analisar a situação vivida pela mulher no cárcere, constatar se as detentas estão sendo condenadas à luz dos mesmos princípios aplicados aos homens, bem como analisar se há medidas eficazes para a ressocialização das mulheres encarceradas. O nono capítulo intitulado “A questão brasileira quanto à relação cárcere e maternidade em tempos de pandemia” tem por objetivo tratar das questões ligadas à criminalidade feminina, focada na condição de mulher e mãe apenada no sistema prisional brasileiro, apresentando as imbricações das vulnerabilidades no que diz respeito ao seu acesso à saúde, bem como de seus (as) filhos (as); o enfrentamento no contexto prisional e a luta pelo exercício da cidadania, enquanto dignidade da pessoa humana, diante das contumazes violações dos direitos humanos, mormente agora, diante da pandemia do coronavírus. Por fim, se lança um alerta no sentido do silêncio dos órgãos públicos quanto às situações de internações hospitalares, em caso de contágio, produzindo uma espécie de invisibilidade acerca desse público já notoriamente agredido em sua condição humana. O décimo capítulo intitulado “O Direito à Educação, a legislação de cotas e a implantação de comissões de heteroidentificação” e tem como objetivo tratar da importância do direito à educação como meio de inserção do ser humano em uma sociedade mais justa e igualitária, correlacionado a relevância da aplicação das ações afirmativas por parte do governo federal nas instituições de ensino superior, tendo como campo de estudo a implantação da Comissão de Heteroidentificação para combate às fraudes no ingresso por cotas nas universidades públicas. Para tanto, o sistema de cotas, historicamente e hodiernamente, percorrendo a legislação nacional é explorado. Além disso discorre-se sobre especificidades da diferenciação de cota social e cota racial e sua forma de aplicação na instituição, citando os critérios usados para ingresso como também os grupos beneficiados. O décimo primeiro capítulo intitulado “Implantação da comissão de heteroidentificação em uma universidade do Estado de Minas Gerais” trata da implantação da Comissão de Heteroidentificação para combate às fraudes no ingresso por cotas na Universidade Federal do Triângulo Mineiro. Para tanto, o sistema de cotas, historicamente e hodiernamente, percorrendo a legislação nacional é explorado. Para tanto, são apresentadas todas as medidas que foram tomadas para a concretização e implantação da comissão na instituição, prelecionando os atos iniciais das audiências públicas de discussão sobre o seu cabimento na Instituição, bem como os critérios utilizados nas entrevistas para o ingresso dos discentes. O décimo segundo capítulo intitulado “Perspectivas da vivência e permanência de jovens sobre continuidade no campo após conclusão do Ensino Médio” tem como objetivo analisar as principais perspectivas para a vivência e permanência de jovens sobre continuidade no campo após conclusão do ensino médio, tendo como base o jovem que estudam em salas anexas no município de Vila Rica-MT. A pesquisa foi realizada com os alunos da Escola Vila Rica, que estudam em salas anexas no campo em Vila Rica-MT. Foi realizada uma pesquisa “survey”, por meio da aplicação de um questionário estruturado, os dados coletados foram transferidos, tabulados e analisados por meio de programas próprios para armazenamento de dados, utilizando técnicas descritivas, tabulação cruzada e análise em percentual. Ao analisar as principais perspectivas da vivência e permanência de jovens sobre continuidade no campo após conclusão do ensino médio, a maioria dos estudantes falaram que recebem incentivo dos familiares para permanecer no campo após o término do ensino médio. Os jovens em sua maioria entendem a importância de se fazer o controle dos custos, produção e venda, o que pode dificultar ao produtor saber o real custo da sua produção, fazer planejamento e tomadas de decisões assertivas. O décimo terceiro capítulo intitulado “Desigualdade de gênero na política brasileira: dificuldades e desafios” tem como enfoque a discriminação da mulher no cenário político brasileiro tendo como base o Direito Comparado. Verifica-se a ausência de igualdade de fato, no que tange à paridade de oportunidades e a acesso a cargos públicos. O tema possui relevância jurídica visto que mulheres e homens acessam posições de poder político de diferentes maneiras, mas as mulheres ainda continuam sub representadas na esfera política brasileira. Isso viola o disposto no artigo 5°, inc. I da Constituição Federal Brasileira, que prevê a igualdade entre homens e mulheres em direitos e obrigações. É necessária uma mudança da mentalidade para que realmente haja a quebra dos estereótipos de identidade de gênero ainda existentes. O décimo quarto capítulo intitulado “O que os professores devem saber sobre as dificuldades de aprendizagem para facilitar o processo de ensino e aprendizagem?” se propõe realizar pesquisa sobre as dificuldades de aprendizagem. Objetiva-se identificar as suas principais causas, consequências, as formas de diagnóstico, tratamentos ou intervenções. Tanto a escola quanto a família são agentes relevantes na formação do educando, pois o mesmo se desenvolve a partir do contexto ao qual ele está inserido. A escola e a família devem procurar meios para estabelecer uma parceria e garantir educação de qualidade ao aluno. Porém, na maioria dos casos ocorre um distanciamento entre essas instituições, o que acaba desestimulando a criança a querer aprender. O décimo quinto capítulo intitulado “A participação feminina nos cursos de graduação da Escola Naval: uma história de conquistas” tem por objetivo apresentar a participação histórica da jovem mulher militar oriunda da EN. A abordagem é qualitativa, com pesquisa documental e bibliográfica como técnicas iniciais exploratórias e com dados de pesquisa longitudinais, de 2014 a 2021. A participação das mulheres em diversas ocupações profissionais até pouco tempo masculinas está em crescimento. A história de conquistas femininas é, sem dúvidas, marcante na construção de uma oficialidade que representa uma parcela da sociedade brasileira. As futuras oficiais estão a aprender os comportamentos desejáveis que seguirão na profissão militar, de dedicação à Marinha, à Nação, sem se esquecerem de que são mulheres e cidadãs, integrantes ativas de uma sociedade que busca um país desenvolvido, forte, livre, igualitário, justo e soberano. O décimo sexto capítulo intitulado “Discutir gênero - Identidade de gênero e sexualidade interseccionando as experiências de mulheres e homens transexuais” aborda perspectivas referentes à identidade de gênero e sexual tomando-se como referência a experiência transexual. Mostra-se imprescindível refletir sobre a sexualidade e sobre os questionamentos e colocações equivocadas em relação aos corpos e identidades de mulheres e homens trans. Busca-se o entendimento de que identidade de gênero e orientação sexual são demandas pessoais – íntimas em relação a gênero e corpo sendo este, inclusive, um lugar de enunciado político. O décimo sétimo capítulo intitulado “Reconhecimento das diferenças e superação dos preconceitos frente à diversidade sexual no âmbito educacional” tem como objetivo apresentar a diversidade sexual dentro do âmbito escolar, promovendo assim, o reconhecimento das diferenças e superação dos preconceitos que tem raízes culturais em tabus estigmatizados pela sociedade que vê a diferença como algo fora da ordem social. A pesquisa tem uma abordagem qualitativa, de natureza básica, com objetivo explicativo através do procedimento bibliográfico, onde foram feitas pesquisas em livros, artigos e monografias disponíveis via online. O décimo oitavo capítulo intitulado “Cultura do Estupro no Brasil: um mal a ser combatido” trata dos estarrecedores índices de violência contra a mulher no Brasil, especialmente no caso de estupros, que maculam não somente o corpo, mas o psicológico das mulheres agredidas. No caso, será apresentado um panorama da legislação de combate à violência contra a mulher no Brasil, que mesmo sendo de excelência no que concerne ao arcabouço jurídico, ainda não é realidade de forma prática no Brasil. Por fim, será apresentada a cultura do estupro no Brasil, mal esse que necessita ser combatido, sendo necessária uma mudança urgente desse modo negativo de agir e pensar do brasileiro em relação à mulher. O décimo nono capítulo intitulado “Posicionamentos sobre a mulher indígena na produção científica em saúde” buscou problematizar as construções discursivas sobre saúde e cuidado presentes na literatura acadêmica brasileira acerca de mulheres indígenas. Para tal, foi produzida uma revisão da literatura nas plataformas de indexação do SciELO, BVS-Psi, BDTD e Catálogo de Teses e Dissertações da CAPES, localizando um total 90 trabalhos, sendo, 8 artigos e 2 dissertações do campo da saúde analisados neste trabalho. Buscou-se então identificar, nessa literatura, os conceitos de saúde e cuidado; analisar como as mulheres indígenas são discursivamente posicionadas com relação às práticas de cuidado com a saúde. O vigésimo capítulo intitulado “A atuação do CREAS na violência doméstica contra mulheres: reflexões sobre o contexto de necropolítica na pandemia” tem como objetivo analisar a violência doméstica contra mulheres nesse contexto de necropolítica na pandemia, devido ao seu crescimento, inclusive em relação às demais minorias sociais, conforme será discutido por meio de dados quantitativos e qualitativos. Serão, também, apresentados desafios para as políticas públicas de enfrentamento à violência doméstica contra mulheres, com ênfase no Centro de Referência Especializado de Assistência Social, criado a partir dos princípios do Sistema Único de Assistência Social. Pretende-se, assim, dar visibilidade e desnaturalizar perspectivas essencialistas sobre a desigualdade de gênero e sobre o descaso do Estado frente a esse contexto, ressaltando a relevância de uma análise crítica e psicossocial de enfrentamento à violência doméstica contra mulheres. O vigésimo primeiro capítulo intitulado “Não morrer nem sempre é viver: análise do auxílio emergencial para proteção das mulheres negras na pandemia de Covid-19” pretende o escrutínio e a reflexão sobre a novel norma de Auxílio Emergencial, a Lei nº 14.171/21, analisando-a no âmbito do Direito de Família, dos Direitos da Criança e do Adolescente, e especialmente no tocante aos direitos das mulheres, encontrando-se socialmente inserido dentre as críticas ao modelo patriarcal e racial de sujeição feminina. Propõe-se, então, a utilizar as abordagens antropológica e jurídica para investigar os contextos de opressão de gênero, raça e classe diante do cenário da Pandemia de Covid-19, como reflexo do aprofundamento de vulnerabilidades históricas. O vigésimo segundo capítulo intitulado “Cotas como estratégia política do movimento negro: um debate necessário” pretende analisar a lei nº 12.711/2012, visando subsidiar a garantia de direito. Assim como, compreender a importância do movimento negro e do Serviço Social para a concretização das cotas. Trata-se de uma pesquisa bibliográfica, a partir da utilização de publicações de autores sobre os assuntos que compõem o tema. Constata-se que o sistema de cotas étnico-raciais é de extrema importância, sem ela, o ingresso da população negra no ensino superior público, seria quase inexistente, afinal, mesmo com as garantias constitucionais e as legislações pertinentes a esta temática como a Lei Federal 12.288/2010 (que dispõe sobre o Estatuto de Igualdade Racial), assim como o Projeto de Lei 73/1999 e 213/2003 e a referida Lei, continua desqualificando os não brancos, por não conseguirem ter acesso a esse direito por intermédio da competição, do esforço individual, afinal, dentro dos moldes do capitalismo, é isso que vale e importa. O vigésimo terceiro capítulo intitulado “Questões de gênero em noticiários: educação, trabalho e lutas sociais” tem como objetivo apresentar concepções de gênero em noticiários nacionais. Especificamente, caracterizar noticiários nacionais associados ao gênero; realizar uma releitura de noticiários, associando-os ao conhecimento cultural. Desse modo, optou-se por um estudo descritivo com abordagem qualitativa. Para a realização do estudo foram selecionados 10 noticiários publicados no ano de 2017. Após a seleção das fontes de dados, estes foram identificados, classificados e analisados A análise do material de estudo ocorreu de forma interpretativa nas categorias educação, trabalho e lutas sociais contra o sexismo. Com as análises constatou-se que ainda são altos os índices de analfabetismo entre mulheres; que a desigualdade salarial ainda é evidente entre homens e mulheres, embora essas tenham papel participativo na sociedade; que as lutas contra o sexismo não podem parar pois a violência doméstica ainda faz parte da vida de muitas mulheres, embora a Lei Maria da Penha tenha lhes assegurado alguns direitos. Por fim, que prevalece uma cultura hegemônica e machista no nosso país e que se faz necessário maior conscientização da população para a tratativa da temática gênero. O vigésimo quarto capítulo intitulado “Os voos rasantes num mundo em ruínas: um ensaio sobre o racismo em tempos de Covid-19” traz como proposição criar um terreno reflexivo, compondo zonas de encontro entre o saber e o transmitir. A proposição do texto se encontra numa encruzilhada de pensamentos e reflexões que constituem a base da discussão em torno da vida. O ensaio proposto tem como objetivo criar rachaduras para outros conhecimentos, desta forma criando um espaço para que as palavras possam respirar e tomar forma. Os caminhos percorridos vão de encontro a necropolítica instaurada e perpetuada através dos anos e formas de resistência e realidade dos/as jovens negros/as brasileiros. O vigésimo quinto capítulo intitulado “A mulher idosa e a invisibilidade da violência psicológica” tem como objetivo analisar a violência praticada contra pessoas idosas como sendo multifatorial. As mulheres sofrem mais violência em todas as faixas etárias, fato que se agrava com o envelhecimento, adoecimento e ao gênero. A violência contra a mulher idosa pode ser caracterizada como agressão física, verbal, moral, psicológica, sexual, negligência ou abandono, tanto social quanto institucional, caracterizando-se como um grave abuso aos direitos humanos. A Violência Psicológica resulta em sequelas tão graves como as causadas por agressões físicas e, em muitos casos, são desenvolvidos quadros de estresse pós-traumático, depressão, ansiedade, ideações suicidas, entre outros. A Violência Psicológica contra a mulher foi tipificada como crime por meio da Lei nº 14.188/2021. Em diversos contextos, as idosas vítimas de violências, negam-se a adotar medidas legais contra os agressores, que geralmente são membros da família ou a discutir sobre esse assunto com terceiros. Portanto, entende-se que os abusos sejam ainda mais prevalentes e, portanto, subnotificados. Espera-se que esse estudo possa facilitar uma discussão sobre o tema da violência psicológica contra a mulher idosa, um tema ainda tão pouco explorado. O vigésimo sexto capítulo intitulado “Vulnerabilidade da população trans profissional do sexo à manifestações bucais de infecções sexualmente transmissíveis” tem como objetivo identificar as vulnerabilidades em relação às manifestações bucais de IST no grupo alvo. A metodologia seguiu os princípios de uma Revisão de Literatura Narrativa, tendo sido realizada coleta de referencial teórico em sites de bases de dados, tais como Pubmed, SciELO e LILACS. As etapas da pesquisa consistiram em identificar, selecionar e fazer o fichamento de 38 artigos diretamente relacionados ao tema. De acordo com o referencial teórico utilizado, compreende-se que a constante dialética entre as demandas da população trans e o imperativo heterossexual cisgênero, envolve processos de adoecimento, discriminação, preconceitos e privação de direitos fundamentais. Estes, associados à presença de comportamentos de riscos quanto à contaminação por IST; à prostituição enquanto principal destino para obtenção de renda; às baixas taxas de qualidade e expectativa de vida, e às altas taxas de mortes violentas, evidenciam a necessidade urgente de ações que assegurem os direitos fundamentais dessa minoria. Nesse contexto, os autores concluem que há a necessidade de criar e efetivar políticas públicas de alcance nacional, que busquem mudanças de ordem estrutural e social, estabelecendo redes de apoio, fortalecimento dos vínculos com os serviços de saúde e incentivo sobre prevenção. O vigésimo sétimo capítulo intitulado “Observatório dos Direitos das Mulheres dos Vales do Jequitinhonha e Mucuri-UFVJM: dilemas e desafios nas suas ações em tempos de Covid-19” busca destacar os principais dilemas e desafios para dar continuidade ao desenvolvimento das ações realizadas pelo Observatório dos Direitos das Mulheres dos Vales do Jequitinhonha e Mucuri – ODMVJM da UFVJM, durante a pandemia do novo coronavírus (COVID-19), com destaque para as possibilidades das ações efetivadas, no contexto de trabalho remoto da extensão universitária na UFVJM. Este projeto de extensão foi iniciado em agosto de 2016, por meio da articulação com o ensino e pesquisa. Desde sua criação, o projeto vem promovendo importantes contribuições na defesa dos direitos da mulher e principalmente no enfrentamento a violência contra a mulher nos Vales do Jequitinhonha e Mucuri. O vigésimo oitavo capítulo intitulado “Mulheres que curam: matriarcas responsáveis pela transmissão de ser rezadeira” ressalta que as rezadeiras são mulheres de núcleos periféricos de suas cidades, atuando como curandeiras onde os sistemas de saúde possuem dificuldades de ingresso. São mulheres velhas, que por muita das vezes, são as chefes de família, detentoras da maior parte da economia da casa. Elas retêm sua subsistência e de sua família a partir de planos de governo, como aposentadoria e bolsa família. O ofício da reza é transmitido para as mulheres dentro de um núcleo familiar. Por fim, o vigésimo nono capítulo intitulado “Gênero e Lei Maria da Penha: atravessamentos na concessão de medidas protetivas” procede-se a um breve resgate histórico da construção e de distintas compreensões teóricas sobre o gênero, através de considerações introdutórias da formulação proposta por Scott (1990), seguindo-se da crítica ao seu emprego a partir de estudos apoiados em Butler e em marxistas, especialmente materialistas. Conclui-se que o debate em torno do gênero não é uníssono e encontra-se em constante movimento no âmbito das ciências humanas e sociais, nos debates feministas e no campo do direito, com rebatimentos nas discussões e formulações jurídicas, logo, repercutindo na operacionalização da lei Maria da Penha e exigindo postura atenta das equipes multidisciplinares. Por isso, a obra que ora se apresenta é de leitura obrigatória para estudantes e profissionais de todas as áreas que queiram compreender e formar opinião acerca dos estudos de gênero e suas interseccionalidades, que transcendem diversas áreas do conhecimento. Além disso, diante de tais debates importantes trazidos na presente obra podem surgir soluções e respostas para a resolução de diversas questões polêmicas em pauta em nosso país e no mundo. Da organizadora, tendo como base os trabalhos apresentados pelos autores. Tenham uma ótima leitura!

Abstract Genotype evaluation for stability and high yield in rice is an important factor for sustainable rice production and food security. These evaluations are essential, especially when the breeding objective is to release rice with high yields, adaptability and stability for commercial cultivation. To achieve this objective, this study was carried out to select high-yielding rice genotypes induced by ion beam irradiation. Seeds of the rice variety 'MR219' were subjected to different doses of 320 MeV carbon-ion beam irradiation to determine the optimum dose to produce high mutant frequency and spectrum. The optimum dose was 60 Gy. After several cycles of selection and fixation between 2009 and 2014 (M₀-M₆), six prospective lines with desirable characters were selected at the M6 generation. The selected mutant lines along with other mutant varieties were then tested at five locations in two planting seasons to select high-yielding and stable genotypes. The experiment was conducted in a randomized complete block design with three replications across the locations and seasons. The pooled analysis of variance revealed highly significant differences (p ≤ 0.01, 0.05) among genotypes, among locations and among genotypes by location by season (G×L×S interaction) for the yield traits except for seasons and genotype by season (G×S interaction). Based on univariate and multivariate stability parameters, rice genotypes were classified into three main categories. The first group comprised genotypes with high yield stability along with high yield per hectare. These genotypes include ML4 and ML6 and are widely adapted to diverse environmental conditions. One line exhibited high yield per hectare but low stability; this genotype (ML9) is suitable for specific environments. The last group had low yield per hectare and high stability and included 'MR220', 'Binadhan4' and 'Binadhan7'. This final group is more suitable for breeding specific traits or perhaps has yield component compensation. Hence, rice mutant lines ML4 and ML6 were recommended for commercial cultivation in Malaysia.

AbstractOrogenic gold deposits formed in various terranes of most ages since the Paleoarchean and generally consist of quartz veins hosted in shear zones formed at the ductile brittle transition under greenschist to lower amphibolite metamorphic conditions. Vein mineralogy is dominated by quartz with various amounts of silicates, carbonates, phyllosilicates, borates, tungstates, sulfides, and oxides. The isotopic composition of these minerals and fluid inclusions has been investigated since the 1960s to constrain the characteristics of orogenic fluid systems involved in the formation of gold deposits worldwide. This review is based on 8580 stable isotope analyses, including δ18O, δD, δ13C, δ34S δ15N, δ11B, and δ30Si values, from 5478 samples from 558 orogenic gold deposits reported in the literature from 1960 to 2010. This contribution describes the variability of the light stable isotopic systems as function of the minerals, the age of the deposits, their regional setting, and their country rocks. The temperature of isotopic equilibrium of orogenic gold veins is estimated from mineral pairs for oxygen and sulfur isotopes. Based on these temperatures, and on fractionation between mineral and fluid components (H2O, CO2 and H2S), the isotopic composition of fluids is estimated to better constrain the main parameters shared by most of auriferous orogenic fluid systems. Orogenic gold deposits display similar isotopic features through time, suggesting that fluid conditions and sources leading to the formation of orogenic gold deposits did not change significantly from the Archean to the Cenozoic. No consistent secular variations of mineral isotope composition for oxygen (−8.1‰ ≤ δ18O ≤ 33‰, n = 4011), hydrogen (−187‰ ≤ δD ≤ −4‰, n = 246), carbon (−26.7‰ ≤ δ13C ≤ 12.3‰, n = 1179), boron (−21.6‰ ≤ δ11B ≤ 9‰, n = 119), and silicon (−0.5‰ ≤ δ30Si ≤ 0.8‰, n = 33) are documented. Only nitrogen (1.6‰ ≤ δ15N ≤ 23.7‰, n = 258) and sulfide sulfur from deposits hosted in sedimentary rocks (−27.2‰ ≤ δ34S ≤ 25‰, n = 717) display secular variations. For nitrogen, the change in composition is interpreted to record the variation of δ15N values of sediments devolatilized during metamorphism. For sulfur, secular variations reflect incorporation of local sedimentary sulfur of ultimate seawater origin. No significant variation of temperature of vein formation is documented for orogenic gold deposits of different ages. Quartz-silicate, quartz-carbonate and sulfide-sulfide mineral pairs display consistent temperatures of 360 ± 76 °C (1σ; n = 332), in agreement with the more common greenschist facies hostrocks and fluid inclusion microthermometry. Fluid sources for orogenic gold deposits are complex but the isotopic systems (hydrogen, boron, carbon, nitrogen, oxygen, sulfur) are most consistent with contributions from metamorphic fluids released by devolatilization of igneous, volcano-sedimentary and/or sedimentary rocks. The contribution of magmatic water exsolved from magma during crystallization is not a necessary component, even if permissible in specific cases. Isotopic data arrays can be interpreted as the result of fluid mixing between a high T (~550 °C)—high δ18O (~10‰)—low δD (~−60‰) deep-seated (metamorphic) fluid reservoir and a low T (~200 °C)—low δ18O (~2‰)—high δD (~0‰) upper crustal fluid reservoir in a number of orogenic gold deposits. The origin of the upper crustal fluid is most likely sea- or meteoric water filling the host rock porosity, with a long history of water–rock isotope exchange. Mixing of deep-seated and upper crustal fluids also explains the large variation of tourmaline δ11B values from orogenic gold veins. Regional spatial variations of oxygen and hydrogen isotope compositions of deep-seated fluid reservoirs are documented between orogenic gold districts. This is the case for the Val-d’Or (Abitibi), Coolgardie and Kalgoorlie (Yilgarn) where the oxygen isotope composition of the deep-seated fluid end-member is 4‰ lower compared to that from the Timmins, Larder Lake, and Kirkland Lake districts (Abitibi). However, both mixing trends converge towards a common, low δ18O upper crustal fluid end-member. Such variations cannot be related to fluid buffering at the site of deposition and suggest provinciality of the fluid source. The contribution of meteoric water is mainly recorded by fluid inclusions from Mesozoic and Cenozoic age deposits, but micas are not systematically in isotopic equilibrium with fluid inclusions trapped in quartz from the same vein. This suggests late involvement of meteoric water unrelated to deposit formation. Yet, a number of deposits with low δD mica may record infiltration of meteoric water in orogenic gold deposits. Isotope exchange between mineralizing fluid and country rocks is documented for oxygen, carbon, sulfur and silicon isotopes. Large variations (> 10‰) of sulfide δ34S values at the deposit scale are likely related to evolving redox conditions of the mineralizing fluid during reaction with country rocks. Deposits hosted in sedimentary rocks show a shift to higher δ18O values as a result of fluid/rock oxygen exchange with the regional sedimentary country rocks.

Abstract This chapter covers the following topics: allotropic modifications of carbon; compounds of carbon, bonding in carbon compounds; gold and silver carbone complexes; phosphine-sulfoxide carbon(0) complexes; structural chemistry of silicon; structures of halides and oxides of heavier Group 14 elements; polyatomic anions of Ge, Sn, and Pb; organometallic compounds of heavier Group 14 elements; tetrel bonding interactions in tin and lead compounds; as well as tetrylones.

Fused deposition modeling (FDM) is highly commercialized Rapid Prototyping (RP) technology for its ability to build complex parts with low cost in a short period of time. The process parameters in the FDM play a vital role in the mechanical properties of the polymeric parts. Most of the research studies show that the variable parameters such as orientation, layer thickness, raster angle, raster width, and air gap are some of the key parameters that affect the mechanical properties of FDM-processed polymeric parts. However, no reports have been made regarding the influence of nozzle diameter with raster width on the tensile properties of FDM fabricated polymeric parts. This work was devoted to achieving improved and isotropic mechanical properties in polycarbonate (PC) and PC/carbon nanotube (PC/CNT) nanocomposites by investigating the effect of printing parameters in FDM process. The nozzle diameter to raster width ratio, α was found to significantly affect the mechanical properties. The printing direction dependency in tensile properties were studied with the ratio α < 1 and α≥ 1 at three different raster angles of 0°, 45°/−45° and 90°. For α < 1, Ultimate tensile strength and modulus of elasticity were higher for 0°, compared to 45°/−45° and 90° raster angles. However, for α ≥ 1, the ultimate tensile strength and the modulus of elasticity showed little dependency to print direction. This certainly determines the decrease in anisotropy at higher values of α. Mesostructure characterization with microscopy and image analysis were used to further explain the printing behavior and the resultant properties of the printed samples.

The prominence of carbon fiber reinforced polymers (CFRP) has made advancements in many industries including aerospace, automotive, and sporting goods. Using additive manufacturing to produce the CFRPs allows prototyping complex geometries while keeping the structure lightweight and producing a high strength material. This work studies the printing parameters and flexural strength of 3D printed onyx based CFRP samples, looking at the effect of variable parameters affecting the carbon fiber layers. A Markforged Mark 2 3D printer, which utilizes a dual head print head, is used to print nine different configurations of the CFRP composite. Each sample consists of 24 layers of material with an infill of 50%, two wall layers, as well as four roof and floor layers. The configurations examine the extreme of three parameters with reference to the carbon fiber, being the fiber angle, number of fiber layers, and the position of the fiber layers. The carbon fiber print angle is printed with layers at 0˚, 0˚/45˚, and 0˚/90˚ with the latter two switching between the respective angles for every layer of carbon fiber printed. The number of fiber layers are set to be either 4 or 16. The position of fiber layers includes all layers (excluding roof/floor); the two outer most layers (which are directly below/above the roof/floor layers); and the four middle layers of the sample. The 3D printed CFRP specimens are subjected to three-point bend test, and three samples are tested for each configuration. One sample is chosen from each configuration to undergo pre-test and post-test inspection using X-ray micro-computed tomography to examine any internal damages.

The fatigue crack growth analysis of nuclear piping is a nonlinear calculation process. The loading sequence and combination mode could affect the results. How to consider these effects is unclear. Fatigue crack growth analysis includes a large number of nonlinear iterative calculations, and the calculation speed is slow. This paper selects carbon steel nuclear piping as the research object. Based on the analysis process provided by ASME code XI volume, a simplified analysis method is explored by introducing the reference crack depth a’ and the envelope transient. The simplified analysis method is conservative because it has been proved that the crack growth rate is positively related to the crack size only if the maximum stress intensity factor is greater than 0 and the minimum stress intensity factor is less than 0. The simplified analysis method is proved to be able to significantly improve the calculation speed by comparing the number of iterative calculations in the simplified analysis method and in the conventional analysis method. The results indicate that the simplified analysis method could provide a conservative way of loading and combining the complex transients and could significantly reduce the number of nonlinear iterative calculations in the process of crack fatigue growth analysis for carbon steel nuclear piping when the maximum stress intensity factor greater than 0 and the minimum stress intensity factor is less than 0.

Fiber reinforced polymers are widely used in the transportation, aerospace and chemical industries. In rare instances these materials are produced net-shape, and secondary processing such as machining and assembly may be required to produce a finished product. Because fiber reinforced polymers are heterogeneous materials, they do not machine in a similar way to metals. Thus, the theory of metal machining is not valid for the analysis of machining of fiber reinforced composites. Previous attempts in modeling this problem have adopted Merchant’s theory for metal cutting by assuming that chip formation takes place in a shear plane where the inclination angle is determined by the minimum energy principle. This class of models showed that model predictions are valid only for fiber orientations less than 60°. Furthermore, these models are incapable of predicting cutting forces for multidirectional laminates or complex tool geometry. The work presented here focuses on providing a predictive model for the cutting forces in milling both unidirectional and multidirectional laminates. The model is based on the specific cutting energy principle and accounts for a wide range of fiber orientations and chip thickness. Results from this model were found to be in good agreement with experimental results over the entire range of fiber orientations from 0 to 180°.

Additive manufacturing or 3D printing of short carbon fiber composites is highly inclined toward thermoplastic material. Recently, there is some interest in developing 3D printing technology for thermosetting polymers and composites. Direct-ink-writing (DIW) of short fiber epoxy composites containing milled carbon fibers (MCF) exhibits the potential to replace the traditional composite material as it showcases the inherent capability of fabricating complex geometries, facile material processing, continuous printing capability coupled with low cost. Previous research in 3D printing of short carbon fiber epoxy composites suffered heavily from the limitation of printing low carbon fiber weight concentrations. This study developed a straightforward technique of designing the epoxy ink containing high weight concentration MCF (~40wt%) and a small concentration of thixotropic filler (3-wt%) for DIW using a pneumatic pressure-driven extruder having micron size tapered nozzle. This paper also intends to contribute to a better understanding of the effect of printing parameters on DIW. Furthermore, the printing parameters were optimized using non-dimensionalized constant C. Optimized printing condition was further used to print different geometry ranging from dog bone with 100% infill to 4-layer hollow circle and 3-layer hollow square with 0% infill. Lastly, ink exhibits the capability to self-support multi-layer geometrical structures during printing.

Abstract A major applications of thermoplastic additive manufacturing (typically completed using the fused deposition modeling or fused filament fabrication (FDM/FFF) process) is in the production of polymer matrix composites. Several different reinforcing materials have been proposed and studied, a common one of which is chopped carbon fibers (CCF). Most of the published research on the properties and effect of the CCF reinforcement has relied upon a poly(lactic acid) (PLA) matrix, as it has a low and stable melting temperature, low cost, and mixes readily with particulate or chopped reinforcing materials. For commercially available CCF filament for FDM/FFF, the typical fiber content is around 15–25% by volume, with the remainder being the thermoplastic matrix. To better explore the influence of the matrix material on the properties of these materials, this study compares the IZOD impact properties of standard CCF PLA with CCF-reinforced materials using polyamide/nylon (PA), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), and polyethylene terephthalate glycol (PETG) matrices. All cases were printed at full (100%) density. For each material, samples of 5 mm thickness were tested in the Type A (notch in tension) and Type E (notch in compression) configurations. Two print orientations (flat and horizontal) and two raster angles (0–90° and ±45°) were considered for each combination. As required by ASTM D256, the tests were replicated five times each. The results are compared with the major literature for CCF reinforced PLA, as well as benchmark tests using injection molded samples and non-CCF PLA, PA, PC, ABS, and PETG processed by FDM/FFF.

This paper details part two of the demonstration of a 2,240 kW (3,005 HP) PR30C-LE locomotive with exhaust aftertreatment containing diesel oxidation catalysts (DOC) and urea-based selective catalytic reduction (SCR). The PR30C-LE is a remanufactured and repowered, six-axle, diesel-electric, line-haul locomotive. Program objectives were to measure emission levels of the locomotive and record locomotive and aftertreatment operations during a 12 month revenue service field trial. Phase 1 of the program involved engine baseline emissions testing as well as emissions testing with the aftertreatment at the beginning of its useful life, or the 0-hour condition. Results from Phase 1 showed engine-out emission levels were within U.S. EPA Locomotive Tier 2 limits. With aftertreatment at beginning of useful life, hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) were below Tier 4 limits, and particulate matter (PM) was below Tier 3 limits. Phase 2 consisted of a 12 month revenue service field trial and additional emissions testing completed at the midpoint and end of the field trial. On-board GPS data, aftertreatment NOx sensor data, and various locomotive operating parameters were logged continuously during the field trial. The field trial data suggests the impact SCR technology has on locomotive NOx emissions is driven primarily by locomotive utilization and loading factor. Overall the field trial included 3,082 hours of operation and PRLX3004 generated approximately 572 MW-hours of work over the 12 month period. Emission test results at the 1,500-hour and 3,000-hour conditions showed very little change from 0-hour test results. Emission levels remained below Tier 4 limits for HC, CO, and NOx, and below the Tier 3 limit for PM. Phase 2 test results suggest there was no significant degradation in emissions performance during the field trial, and no major issues with the locomotive and aftertreatment were detected. In total there are currently five PR30C-LE locomotives in operation within California and Arizona. Together they have completed a cumulative 30,800 hours of revenue service through June 2012 without report of a major issue.

Abstract The Elk Hills and Buena Vista Field, located in the southwest San Joaquin Valley, have over 3000 active wells producing from various reservoirs which are predominantly characterized by a deep marine siliceous shale, or sandstone lithology and are overlain by a shallow marine, tidal-influenced sandstone lithology. Wells are completed as slotted liner, gravel pack, case and perforation, with some wells hydraulically fractured or acid stimulated, producing between 0 and 4000 barrels of liquid per day and 0 to over 1 million standard cubic feet of gas per day. With the variety of reservoirs, and fluid compositions, produced solids and scales accumulate in the surface facility equipment, limiting capacity of vessels, tanks, overall fluid handling capacity and water quality. Dehydration facilities and water treatment facilities experience frequent buildup of sand and scales in the water tanks negatively affecting separation performance and increasing maintenance costs related to tank cleanouts and pump repairs. Excess solids also impact water injectivity and subsurface performance. California Resources Corp (CRC) reviewed options for reducing operating costs, maintenance downtime, and risks from human exposure during maintenance and chose to implement an online sand removal system based on vortex fluidizer technology. This paper discusses implementation of the project and will review major considerations and important decisions made during project design and implementation. The paper will highlight case studies from the literature supporting a decision to select flexible HDPE in lieu of stainless steel and carbon steel for both internal and external slurry lines as a cost saving measure. Special considerations for design of slurry piping and pumping systems will be addressed.

Phononic crystal is an artificial periodic structure in which elastic constants distribute periodically. In this paper, a two dimensional Bragg scattering phononic crystal was introduced into low-frequency noise reduction facility in the brake originally. Through the theoretical analysis by using Plane-wave Expansion Method to obtain the band diagram of a phononic crystal with holes periodically arranged in the 45 carbon steel plate and establishing the equivalent model in motion as the brake, we find an approximate bandgap between 0–5400Hz in the low-frequency range while the complete static bandgaps are distributed in the high-frequency range. It is believed that this kind of extremely low-frequency bandgap is due to the combination of the vibration of a single scatter and the interaction among scatters. In order to demonstrate the theory, contrastive experiment was taken. Noise spectrum diagram of the origin plate without holes was obtained in the first experiment. According to the equivalent model, the two dimensional air column/steel matrix phononic crystal structure in which filling rate was 40% was designed to apply in the test apparatus so that the frequency range (2050 to 2300Hz) of strong noise would be involved in this bandgap. Moreover, the noise in the whole frequency range (0–2550Hz) went down. This phenomenon proved that experiment result was coincident with theoretic consequence. The maximum decreasing amplitude of the noise reached as much as 25dB and the average decreasing amplitude was about 13dB from 2050 to 2300 Hz. In a word, this bandgap which is the combination effect of structure periodicity or the Mie scattering has an obvious extremely low-frequency characteristic in noise and vibration control in the brake.

Abstract As the energy landscape transitions to low/zero-carbon fuels, gas turbine manufacturers are targeting fuel flexible operation with natural gas, syngas, and hydrogen-enriched mixtures. Having a single geometry that can support the different fuel blends requested by clients can accelerate the transition to cleaner energy generation and mitigate the environmental impact of gas turbines. Toward this goal, micromix combustion technology has received significant interest, and when coupled with additive manufacturing, novel injector geometries with unique configurations may be capable of stabilizing premixed, partially-premixed, and diffusion flames using fuel mixtures ranging from pure methane to pure hydrogen. In this work, a preliminary investigation of this micromix concept is performed in the Atmospheric Combustion Rig at the National Research Council Canada. Flame stability maps are obtained for fuel lean mixtures of H2/CH4 ranging from 0/100, 70/30, 90/10, to 100/0%, by volume. Multiple flame shapes are observed depending on the fuel mixture and combustion mode selected. PIV, OH and acetone planar laser-induced fluorescence (PLIF), and acoustic measurements provide additional insights into the combustion process of these novel burners to better understand the stability mechanisms. The quality of the fuel-air mixing from the premixed and micromix injectors is assessed using acetone as a tracer for the fuel, while simultaneous OH-PLIF measurements provide an indication of the post-flame regions in the flow. Acoustic measurements complete the current dataset and provide combustion dynamics maps measuring the normalized pressure amplitudes and identifying the dominant frequencies. The preliminary characterization of this AM micromix nozzle shows promising fuel flexibility with wide stability margins and low combustion dynamics for this single nozzle burner.

The overall goal of this project was to elucidate the role of dissolved organic matter (DOM) in soil retention, bioavailability and plant uptake of silver and cerium oxide NPs. The environmental risks of manufactured nanoparticles (NPs) are attracting increasing attention from both industrial and scientific communities. These NPs have shown to be taken-up, translocated and bio- accumulated in plant edible parts. However, very little is known about the behavior of NPs in soil-plant system as affected by dissolved organic matter (DOM). Thus DOM effect on NPs behavior is critical to assessing the environmental fate and risks related to NP exposure. Carbon-based nanomaterials embedded with metal NPs demonstrate a great potential to serve as catalyst and disinfectors. Hence, synthesis of novel carbon-based nanocomposites and testing them in the environmentally relevant conditions (particularly in the DOM presence) is important for their implementation in water purification. Sorption of DOM on Ag-Ag₂S NPs, CeO₂ NPs and synthesized Ag-Fe₃O₄-carbon nanotubebifunctional composite has been studied. High DOM concentration (50mg/L) decreased the adsorptive and catalytic efficiencies of all synthesized NPs. Recyclable Ag-Fe₃O₄-carbon nanotube composite exhibited excellent catalytic and anti-bacterial action, providing complete reduction of common pollutants and inactivating gram-negative and gram-positive bacteria at environmentally relevant DOM concentrations (5-10 mg/L). Our composite material may be suitable for water purification ranging from natural to the industrial waste effluents. We also examined the role of maize (Zeamays L.)-derived root exudates (a form of DOM) and their components on the aggregation and dissolution of CuONPs in the rhizosphere. Root exudates (RE) significantly inhibited the aggregation of CuONPs regardless of ionic strength and electrolyte type. With RE, the critical coagulation concentration of CuONPs in NaCl shifted from 30 to 125 mM and the value in CaCl₂ shifted from 4 to 20 mM. This inhibition was correlated with molecular weight (MW) of RE fractions. Higher MW fraction (> 10 kDa) reduced the aggregation most. RE also significantly promoted the dissolution of CuONPs and lower MW fraction (< 3 kDa) RE mainly contributed to this process. Also, Cu accumulation in plant root tissues was significantly enhanced by RE. This study provides useful insights into the interactions between RE and CuONPs, which is of significance for the safe use of CuONPs-based antimicrobial products in agricultural production. Wheat root exudates (RE) had high reducing ability to convert Ag+ to nAg under light exposure. Photo-induced reduction of Ag+ to nAg in pristine RE was mainly attributed to the 0-3 kDa fraction. Quantification of the silver species change over time suggested that Cl⁻ played an important role in photoconversion of Ag+ to nAg through the formation and redox cycling of photoreactiveAgCl. Potential electron donors for the photoreduction of Ag+ were identified to be reducing sugars and organic acids of low MW. Meanwhile, the stabilization of the formed particles was controlled by both low (0-3 kDa) and high (>3 kDa) MW molecules. This work provides new information for the formation mechanism of metal nanoparticles mediated by RE, which may further our understanding of the biogeochemical cycling and toxicity of heavy metal ions in agricultural and environmental systems. Copper sulfide nanoparticles (CuSNPs) at 1:1 and 1:4 ratios of Cu and S were synthesized, and their respective antifungal efficacy was evaluated against the pathogenic activity of Gibberellafujikuroi(Bakanae disease) in rice (Oryza sativa). In a 2-d in vitro study, CuS decreased G. fujikuroiColony- Forming Units (CFU) compared to controls. In a greenhouse study, treating with CuSNPs at 50 mg/L at the seed stage significantly decreased disease incidence on rice while the commercial Cu-based pesticide Kocide 3000 had no impact on disease. Foliar-applied CuONPs and CuS (1:1) NPs decreased disease incidence by 30.0 and 32.5%, respectively, which outperformed CuS (1:4) NPs (15%) and Kocide 3000 (12.5%). CuS (1:4) NPs also modulated the shoot salicylic acid (SA) and Jasmonic acid (JA) production to enhance the plant defense mechanisms against G. fujikuroiinfection. These results are useful for improving the delivery efficiency of agrichemicals via nano-enabled strategies while minimizing their environmental impact, and advance our understanding of the defense mechanisms triggered by the NPs presence in plants.