Direct cathodic reduction of Leuco Sulfur Black 1 and Sulfur Black 1

The electrochemical activity of Leuco Sulfur Black 1 in alkaline solution is shown by the means of voltammograms of the dyestuff recorded in a flow cell. The voltammograms indicate the possibility for further dyestuff reduction by cathodic electron transfer. In batch electrolysis experiments successful reduction of Leuco Sulfur Black 1 was achieved using a multi cathode cell. Applying similar experimental conditions cathodic reduction of the insoluble oxidized dyestuff Sulfur Black 1 was achieved. In a first step the dispersed Sulfur Black 1 is reduced to give an alkaline soluble form of the dyestuff that can be reduced further to yield Leuco Sulfur Black 1. Analogous to the electrochemical behaviour of technically produced Leuco Sulfur Black 1, which contains reducing agents, the solution of Leuco Sulfur Black 1 formed by electrolysis is able to undergo further cathodic electron transfer. The cathodic dyestuff reduction is of importance for the development of sulfur dyeing processes which do not require addition of reducing chemicals.     

Dye aggregation in solution: study of C.I. direct red I

The variation of the average number of molecular aggregation for C.I. Direct Red I has been studied in aqueous solutions as a function of the dye concentration, temperature and solution pH. The objective of this paper is to evaluate the optimal conditions and dye structure in the dyeing process. Electrochemical and VIS spectrophotometrical methods have been used to calculate molecular aggregation. The electrochemical calculation uses the reduction process of the dye, and previous calculations by other authors have been reported at a given pH and varying the solution concentration. Molecular aggregation also depends on pH, and an understanding of the reduction mechanism at several pH values is therefore necessary.     

Ozonation of C.I. Reactive Black 5 and Indigo

The ozone transfer for the ozonation of the azo dye Reactive Black 5 (RB5) and indigo was investigated using a bubble column at semi-batch conditions. The results were analyzed by applying film theory and surface renewal theory. The ozonation of both dyes was so fast that an instantaneous reaction directly at the bubble surface can be assumed. The ozone balance in the gas phase was used to determine the volumetric mass transfer coefficient k_La and the enhancement factor E. Besides the measured concentrations, temperature and pressure only the Henry coefficient was required for the determination of k_La and E. By varying the ozone inlet and the dye concentration the reaction regime was identified. The Hatta number Ha which requires uncertain parameters did not have to be determined.     

代替C.I.直接黑38的黑色直接染料的应用研究

研究了3个直接黑色染料的应用性能，与C．I．直接黑38进行了比较，结果显示：这些染料在上染曲线、染色深度、染色工艺、可见光谱和染料色光与C.I.直接黑38近似，在耐光和耐洗牢度方面相当或优于C．I．直接黑38。     

Flow through packed bed reactors: 1. Single-phase flow

Single-phase pressure drop was studied in a region of flow rates that is of particular interest to trickle bed reactors . Bed packings were made of uniformly sized spherical and non-spherical particles (cylinders, rings, trilobes, and quadralobes). Particles were packed by means of two methods: random close or dense packing (RCP) and random loose packing (RLP) obtaining bed porosities in the range of 0.37–0.52. It is shown that wall effects on pressure drop are negligible as long as the column-to-particle diameter ratio is above 10. Furthermore, the capillary model approach such as the Ergun equation is proven to be a sufficient approximation for typical values of bed porosities encountered in packed bed reactors. However, it is demonstrated that the original Ergun equation is only able to accurately predict the pressure drop of single-phase flow over spherical particles, whereas it systematically under predicts the pressure drop of single-phase flow over non-spherical particles. Special features of differently shaped non-spherical particles have been taken into account through phenomenological and empirical analyses in order to correct/upgrade the original Ergun equation. With the proposed upgraded Ergun equation one is able to predict single-phase pressure drop in a packed bed of arbitrary shaped particles to within ±10% on average. This approach has been shown to be far superior to any other available at this time.     

C.I.活性黑5偶合终点控制方法的探讨

使用UV分光光度计测定C.I.活性黑5合成过程中酸性偶合物和C.I.活性黑5最大吸收波长处的吸光度,用二者的比值来控制反应终点.其方法简便、准确,能够数字化控制,减少由视觉引起的误差.     

Inhibiting effect of oxidized zirconium on parasitic cathodic reactions in the sodium chlorate process Part I: Hypochlorite reduction

To clarify the effect of oxidized zirconium on parasitic cathodic reactions in the chlorate process, electrochemical studies were carried out at laboratory scale. The techniques used were cyclic voltammetry and recording of polarization curves. In this paper the reduction of hypochlorite ions to chloride ions was studied. It is shown that oxidized zirconium cathodes reduces the rate of hypochlorite reduction, although not entirely inhibiting it, which is mainly related to a lowered active area due to the porous layer of zirconium dioxide. Further, it has also been shown that the oxidized samples are partly passivated, giving high overvoltages for the hydrogen evolution reaction. These overvoltages gradually decrease during cathodic polarization due to the simultaneous reduction of the zirconium oxide. Studies of the selectivity indicate that hypochlorite reduction occurs on the oxidised zirconium cathodes to a high extent, the thermal oxide being somewhat better. This further proves that zirconium oxide is not a suitable cathode material for the sodium chlorate process.     

Performance of tower loop bioreactors—I: Model calculations for nonlimited growth

The behavior of tower loop reactors is described by a recycle-dispersion model assuming a nonlimited growth rate and negligible residence times of the cell suspension in the loop. For nonsterile feed the parameter ranges of possible steady states are evaluated. In general, recirculation leads to increased biomass concentration. This also causes that unlimited growth may occur even for high Bo numbers. If the feed is sterile, only wash-out and nonlimited growth are found as possible stable steady states.     

The Polymorphism of C.I. Pigment Red 1

The polymorphism of C.I. Pigment Red 1 (1-[(4′-nitrophenyl)-azo] -2-naphthol) in commercial samples has been investigated by interpreting their X-ray diffraction patterns. These have been compared with each other and with those from three single-crystal polymorphs (α, β and γ). It is concluded that commercial samples are predominantly of either one or two phases (α or γ). There is evidence that a fourth phase (δ) exists in powder form.     

Unstable flow of amorphous polymers through capillaries I. Velocity profiles of polymer having discontinuous flow curve

Ciné film was employed for recording the movement of tracer particles, thus directly determining the velocity profile in the capillary flow of model materials of polybutadiene over a range of shear stresses relating to (1.) flow conditions in which there is no distortion of the regular stream of melt emerging from a capillary, (2.) severe surface fracture, (3.) elastic turbulence, (4.) oscillatory flow of melts with discontinuous flow curves. No qualitative difference was found between the velocity profiles in conditions (1) and (2); surface fracture is not related to laminar flow disturbances and originates at the capillary exit. Surface fracture must be distinguished from elastic turbulence. The streamline velocities undergo both local and time variations within the capillary under conditions of developed elastic turbulence; the wall velocity is non-zero. A periodic pulsation of velocities occurs in the flow curve discontinuity region; it takes place throughout the capillary and is caused by stick-slipping of polymer on the capillary wall. The frequency of velocity pulsations coincides with the frequency of extrudate variations.     

Flow through a convergence. Part 1: Critical conditions for unstable flow

The critical conditions leading to fracture in elongation and different types of flow instabilities were examined in uniaxial elongation and in a capillary rheometer equipped with dies having different entry profiles. Either ductile or brittle fracture may be observed, ductile being related to necking of material. The critical stress approach was used to predict fracture in elongation. All linear polymers studied in this work exhibited ductile fracture in uniaxial elongation, but the transition to brittle fracture is discussed in relation to existing experiments with other materials. In a ductile fracture regime, critical stress and work both increase with an increasing rate of deformation, whereas in a brittle regime the critical values remain constant. The converging flow studies indicated that two types of flow instability that have been previously related to each other, namely, pressure oscillations and voltions distortions, are of different origins. The critical flow rate for pressure oscillations is independent of entry profile, and the origin for this type of instability lies along the wall of the capillary. On the other hand, the critical flow rate for volume distortions increased with a decreasing entry angle, indicating that volume distortions are not a consequence of pressure oscillation, nor are their origin at the capillary wall. Numerical simulations were used to determine the stress profiles within the flow, and it was shown that the onset of volume distortions is directly related to the magnitude of elongational stress and work, and may therefore be considered to be caused by fracture in elongation. In dies with 90° entry profile, volume distortions were observed simultaneously with pressure oscillations, making it difficult to distinguish between the two phenomena.     

C．I．颜料红57：1的新制备方法

本文提出一种C.I.颜料红57:1的制备方法,其特征在于,使4B酸在pH＜2及温度＜30℃的条件下重氮化,然后与2,3酸偶合,以氧化钙为原料制备的钙离子悬浮液作为偶合色淀原料及调节pH＞10的条件下,偶合盐析制备C.I.颜料红57:1.根据本方法,可以不使用碎冰设备和较低的反应温度、工艺简便、成本廉价地制备C.I.颜料红57:1.且本方法制备的C.I.颜料红57:1比采用传统方法制备的产品具有更高的透明度和着色力.     

Brabender viscometry: I. Conversion of brabender curves to instron flow curves

Equations have been derived to convert Brabender flow curves to Instron flow curves for practical application purposes. The technique involved is simple and has been described and discussed in detail. Nine pairs of Brabender and Instron flow curves of three different high polymers, each at three operating temperatures, have been found to fit each other quite well. The converted Brabender flow curves overlap a part of the Instron curves and extend the shear range toward the Newtonian flow region. An important consequence of this work is that the Brabender Plastograph can now be regarded as a formal viscometer while still functioning as a miniature of the Banbury mixers used in industry. More work is being done to take advantage of this consequence.     

Combustion of Black Powder. Part 1: Thermo-analytical studies

An experimental programme is described, in which a number of thermo-analytical techniques, differential scanning calorimetry (DSC), thermogravimetry (TG and DTG) are applied to investigate the combustion of black powder. The primary aim has been to investigate, and determine qualitatively and quantitatively, the nature of the solid products of combustion. Additionally, standard analytical techniques were applied, to a chemical analysis of the solid products, resulting from the electric arcignition of a sample of black-powder, under ambient, open air conditions. The solid products formed 33% by weight of the unburned black powder, consisting of K₂SO₄ (15%), K₂CO₃ (11.5%) and small amounts of KNO₃ and KNO₂. The DSC, TG and DTG analyses suggest a mechanism for the combustion, based on phase changes and transition stages of sulfur and KNO₃, and their interaction with charcoal.     

Carbon incorporated FeN/C electrocatalyst for oxygen reduction enhancement in direct methanol fuel cells: X-ray absorption approach to local structures

The C-containing iron nitride electrocatalyst is fabricated by chelating N-containing species and Fe²⁺ with a carbon support under heat treatment in an NH₃ atmosphere, which induces the oxygen reduction reaction activity. This is the first demonstration of forming Fe_xC species on iron nitride materials. The correlation between the electrochemical properties and structures are aided to elucidate their features under investigation by using X-ray absorption spectroscopy. A rotating ring disk electrode test is conducted in sulfuric acid solution and the results reveal the low H₂O₂ yield and approximately 4e⁻ transfer process of the carbon-containing FeN/C electrocatalyst.     

C.I.颜料红48:2的改性

在C I 颜料红48∶2的合成过程中,用不同类型的表面活性剂对其实施表面处理,研究了表面活性剂结构对C I 颜料红48∶2性能的影响。结果表明,添加阴离子表面活性剂、松香及其衍生物以及松香与阴离子表面活性剂、高分子分散剂的复配可以明显改善C I 颜料红48∶2的色光、透明度、流动性、着色力及分散性等多项应用性能。     

The flow of suspensions through tubes: V. Inertial effects

The behavior of particles undergoing Couette and Poiseuille flows at rates when inertial effects become significant was investigated. The rotation of rigid particles was similar to that in the Stokes flow regime, except for a drift of cylinders to limiting rotational orbits corresponding to the maximum energy dissipation. In Poiseuille flow, rigid particles migrated to an equilibrium radial position which depended on the density difference of two phases, the directions of sedimentation velocity and flow, and the ratio of particle to tube radius. Neutrally buoyant deformable particles always migrated to the tube axis. In concentrated suspensions a plasmatic layer developed near the tube wall as a consequence of radial migration. The formation of this layer modified the velocity profile and caused a reduction in the apparent viscosity coefficient.     

Influence of product species selection on thermochemical equilibrium calculations. Part I: Energetic materials

Chemical equilibrium calculations are made for a number of Carbon C, Hydrogen H, Nitrogen N, and Oxygen O, explosive compositions. A methodology is established to systematically limit the number of product species available in thermochemical equilibrium calculations. The calculations are then compared with “baseline” results obtained using an extensive product species library consisting of 900 gas-phase and 600 condensed-phase product species. Errors in bulk thermodynamic properties (detonation velocity and pressure) and in product chemical composition are quantified in terms of the number of species considered as products of reaction. The properties at states along an expansion isentrope are also presented.