New reverse osmosis membrane materials with higher resistance to chlorine

Copolyamides were prepared from mixed diamine components of 3,3′‐ or 4,4′‐diaminodiphenylsulfone, piperazine, and dichlorides such as isophthaloyl or terephthaloyl. The obtained copolyamides are random copolymers, which have good solubilities in organic solvents and good mechanical properties, even in water. The asymmetric membranes prepared from the copolyamides [ex: 4I‐PIP(20)] not only have more excellent reverse osmosis performance, but also higher chlorine resistance than NOMEX‐type aromatic polyamide. New membrane materials with excellent reverse osmosis performance and higher chlorine resistance than the NOMEX‐type aromatic polyamide could be demonstrated successfully. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1357–1364, 2000     

Reverse osmosis performance and chlorine resistance of new ternary aromatic copolyamides comprising 3,3′‐diaminodiphenylsulfone and a comonomer with a carboxyl group

The preparation of asymmetric flat membranes from a series of novel aromatic polyamides comprising 3,3′‐diaminodiphenylsulfone and a comonomer with a carboxyl group(&BOND;COOH) were studied and the measurements of reverse osmosis (RO) performance and chlorine resistance were carried out. It was confirmed that the introduction of comonomer with a carboxyl group (MC or T_m) to the aromatic polyamides (3I or 3T) comprising 3,3′‐diaminodiphenylsulfone was very effective for the improvement of its RO performance. In particular, 3T‐MC(30), which was prepared from terephthaloyl dichloride and mixed diamine components of 3,3′‐diaminodiphenylsulfone and 3,5‐diaminobenzoic acid, exhibited not only some potential for sea water desalination (FR = 159 L/m² day, Rj = 98.3%) but also higher chlorine resistance than conventional Nomex‐type aramid [MI‐MC(0)]. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 505–513, 2001     

Current status of seismic and borehole measurements for HDR/HWR development

Seismic and borehole measurements provide significant information about HDR/HWR reservoirs that is useful for reservoir development, reservoir characterization, and performance evaluation. Both techniques have been widely used during all HDR/HWR development projects. Seismic measurements have advanced from making passive surface measurements during hydraulic fracturing to making passive observations from multiple boreholes during all phases of HDR/HWR development, as well as active seismic measurements to probe regions of the reservoir deemed to be of interest. Seismic data provide information about reservoir extent, locations and orientations of significant fractures, and areas of thermal drawdown. Recent advances include the ability to examine structures within the seismically active zone using statistics-based techniques and methods such as seismic tomography. Seismic method is the only means to obtain direct information about reservoir characteristics away from boreholes. Borehole measurements provide high-resolution information about reservoir characteristics in the vicinity of the borehole. The ability to make borehole measurements has grown during the course of HDR/HWR development as high temperature tools have been developed. Temperature logging, televiewer logs, and electrical property measurements have been made and shown to provide useful information about locations of fractures intersecting wellbores, and regions where water leaves and enters injection and production wellbores, respectively.     

High Performance Ferrous MIM Components Through Carbon and Microstructural Control

This study on metal injection molding considers the combined influences of the type of powder, subsequent debinding and sintering conditions on the carbon control and microstructure for high performance ferrous materials. Carbon retention and sintered microstructure vary significantly with the powder type. Although carbon retention is sensitive to the debinding and sintering atmospheres and conditions, the carbon content can be successfully controlled by adjusting the weight loss after deb'inding. Mechanical properties are also investigated and compared with that of conventional P/M and wrought materials, some factors affecting the properties are discussed taking the microstructure into account. Finally, high performance properties depend on two types of microstructure, one is the fine homogeneous microstructure in the case of high alloy steels and the other is the fine heterogeneous microstructure in the case of low alloy steels.     

Decomposition of NO on Na+-modified MgO evidenced by ESR and temperature programmed desorption (TPD)

The decomposition of NO to N₂O is accompanied by the formation of O^– over a Na⁺-modified MgO surface at moderated temperatures. The importance of the interaction of (Na⁺) _n (n2) clusters and MgO surface is highlighted.     

Structure and reactivity of MoO3-MgO catalysts

Surface of OH groups on reduced MoO₂-MgO catalysts such as $$ - - Mg - - O - - \begin{array}{*{20}c} {||} \\ {Mo} \\ | \\ \end{array} - - OH$$ may act as an active site for hydrogenation of propene. The surface hexa-coordinated Mo⁵⁺ ion (MO _6c ⁵⁺ ) was reduced to a lower number of cation such as Mo⁴⁺ or Mo³⁺ which act as an active site for metathesis of propene.     

High power and high focusing CWCO2 laser using anunstable resonator with a phase-unifying output coupler

A high-power and high-focusing continuous-wave (CW) CO₂ laser with a novel unstable resonator was developed. This resonator contains a step-wise variable reflecting output coupler named the phase-unifying output coupler and a total reflector. The laser was excited by a capacitive-barriered AC discharge called a silent discharge. A linearly polarized laser beam with a diffraction-limited divergence angle of 0.55 mrad was obtained. Very stable CW laser operation at an output power of 5 kW was achieved with a threshold discharge power of 10 kW and a slope efficiency of 18%     

Fast axial flow CO2 laser excited by silent discharge

A fast axial flow CO₂ laser excited by silent discharge has been developed. With a new electrode system applied to the laser, homogeneous discharge of power density of up to 80 W/cm³ is obtained without applying any stabilization techniques on the discharge. An output laser power of 920 W in stable TEM₀₀ mode operation is attained with an efficiency of over 14%. Beam fluctuation common to fast axial flow lasers is suppressed by the combination of smooth gas flow and low CO₂ molar fraction     

Effect of SO42− on catalytic activity of Fe2O3 for hydrocracking of coal

The catalytic activity of Fe₂O₃for the hydrocracking of a bituminous coal at 673K increases when a small amount of SO₄^2? is included in the catalyst. The effect of SO₄^2? is marked in the formation of resins, stronger polar compounds and asphaltenes.     

Shape selective catalytic behaviors of nickel ion-exchanged layered potassium niobate

The alcohol decomposition and olefin hydrogenation on the hydrogen-treated Ni ion-exchanged (exchange degree, 30%) potassium niobate (Ni-K₄Nb₆O₁₇) were performed. Formation of propene from i-propanol on Ni-K₄Nb₆O₁₇ was much smaller than that observed on bulk Nb₂O₅, while the olefin yields from ethanol and n-propanol were almost the same on both catalysts. The 1- butene hydrogenation did not proceed on Ni-K₄Nb₆O₁₇, whereas propene hydrogenation took place rapidly on the same catalyst at 80°C.

The formation of the acid sites and Ni metallic sites by hydrogen treatment at 300 °C was proposed by using temperature-programmed reduction (TPR) and extended X-ray absorption fine structure (EXAFS). These results suggest that Hg₂-treated Ni-K₄Nb₆O₁₇ acts as a shape selective acid- and metal-catalyst at suitable reaction temperatures.