Pre-treatment of dielectrics and technological process for deposition of chemical copper layers from copper solution with improved ecological impact

ABSTRACT

In the metallisation of dielectrics, this process and the deposited metal layer quality is influenced by the dielectric pre-treatment, and the solution compositions for both pre-treatment and metallisation are vital for establishing the optimum operating conditions for metal layer deposition. The investigations in this study were carried out on samples of acrylonitrile–butadiene-styrene (ABS – Novodur PM/2C Type, Bayer) with a working surface of 0.1 dm². The investigated operations of the technological scheme for pre-treatment are as follows: degreasing, etching, reduction, pre-activation, activation. After passing through these operations, the ABS samples were subjected to chemical deposition of copper layers from a recently-developed solution. The copper layers were characterised by AFM, SEM, EDX, XRD and XPS analyses.     

Layers obtained on aluminum by nanopowder deposition and subsequent electron beam scanning

The scanning circular rotating motion of the electron beam is used for embedding unclad TiCN nanoparticles in the aluminum matrix. The most appropriate treatment conditions for obtaining layers with significant thickness and high microhardness are reported. Layers with thickness 14–33?µm and microhardness 562–798?kg/mm², which is 16–22 times higher than the substrate microhardness, are obtained. Possible strengthening mechanisms of the layers are discussed. The layers, chemical, and phase compositions are investigated by EDX detector of SEM and XRD. The complex investigation is completed with TEM analysis. Incorporated TiCN nanoparticles are observed in the aluminum matrix. Layers with such characteristics could be convenient for details to which high surface hardness and light, soft, and plastic base metal are required.     

Development of a membrane‐assisted hybrid bioreactor for ammonia and COD removal in wastewaters

A new membrane‐assisted hybrid bioreactor was developed to remove ammonia and organic matter. This system was composed of a hybrid circulating bed reactor (CBR) coupled in series to an ultrafiltration membrane module for biomass separation. The growth of biomass both in suspension and biofilms was promoted in the hybrid reactor. The system was operated for 103 days, during which a constant ammonia loading rate (ALR) was fed to the system. The COD/N‐NH₄⁺ ratio was manipulated between 0 and 4, in order to study the effects of different organic matter concentrations on the nitrification capacity of the system. Experimental results have shown that it was feasible to operate with a membrane hybrid system attaining 99% chemical oxygen demand (COD) removal and ammonia conversion. The ALR was 0.92 kg N‐NH₄⁺ m^?3 d^?1 and the organic loading rate (OLR) achieved up to 3.6 kg COD m^?3 d^?1. Also, the concentration of ammonia in the effluent was low, 1 mg N‐NH₄⁺ dm^?3. Specific activity determinations have shown that there was a certain degree of segregation of nitrifiers and heterotrophs between the two biomass phases in the system. Growth of the slow‐growing nitrifiers took place preferentially in the biofilm and the fast‐growing heterotrophs grew in suspension. This fact allowed the nitrifying activity in the biofilm be maintained around 0.8 g N g^?1 protein d^?1, regardless of the addition of organic matter in the influent. The specific nitrifying activity of suspended biomass varied between 0.3 and 0.4 g N g^?1 VSS d^?1. Copyright © 2004 Society of Chemical Industry     

Deformation Effects on the Structure and Properties of Y1−x Ca x Ba2Cu3O7−δ (x=0;0.3) Tapes Produced by OPIT Method in the Ag-Tube

Samples of superconducting tapes with two type cores (YBa₂Cu₃O_7−y and Y_0.7Ca_0.3Ba₂Cu₃O_7−δ ), obtained by the OPIT method under two different regime of rolling—cold (20 °C) and hot (825 °C) are investigated. The superconducting core materials were prepared by standard solid-state technology and fill in the high purity (4N) Ag-tubes. The effect of cold and hot rolling deformation on the orientation of supercoducting crystals were studied by XRD analysis. It was found that a higher degree of texturing in the out of plane direction is obtained after hot rolling deformation in tapes with overdoped core. As a result, the highest critical current density (J _c ) at 77 K and zero magnetic field was achieved in them. J _c increases with the time in the superconducting tapes, which is connected probably with the releasing of stress between the superconducting core and Ag sheat.     

Technical and sanitary aspects of wastewater disinfection by UV irradiation for landscape irrigation.

Water reuse for landscape irrigation requires the production of high quality virus-free effluents to minimize risk for human health. In order to establish the relevance of MS2 phages as an appropriate biodosimeter for UV design, a pilot plant study has been carried out with different types of wastewater effluents. The two pilot systems tested (low-pressure high output and medium-pressure UV units) were able to achieve 4 and 5 log MS2 reduction in tertiary filtered effluent at high calculated UV doses of 170 _ 10 and 300 mJ/cm2, respectively. UV disinfection was extremely efficient for MS2 inactivation in high quality effluents after reverse osmosis: detention times as low as one second and UV dose of 40 mJ/cm2 were sufficient to reach 5 log inactivation of MS2. UV irradiation also produced rapid inactivation of human pathogens such as poliovirus type 1 and indigenous enteroviruses at UV doses up to 3 times lower that those for MS2 disinfection. It was concluded that accurate UV unit design for a given type of wastewater could be ensured by pilot tests using laboratory-propagated MS2 as biodosimeter and collimated-beam tests as the calibration-check.     

The effects of ph on adsorption and desorption of potassium in a granitic soil

Potassium adsorption and release was investigated on samples from six field plots maintained at pH values ranging from 3.8 to 7.5. The slope of the adsorption isotherms, representing the K buffering power of the samples, increased with pH because of the associated increase in cation exchange capacity. Within the pH range 3.8–5.9 there was no difference between the isotherms determined over 10 days compared with 30 min, and the desorption curves were essentially the reverse of the adsorption curves. For the samples with pH 6.7 and 7.5, however, more K was adsorbed over the longer period, and the desorption curves showed hysteresis indicating that some fixation may have occurred. The apparent lack of K fixation in all but the samples of highest pH was attributed to the low clay and high humus content of the soil.     

Solvent Extraction of Copper from Nitrate Media with Chelating LIX‐Reagents: Comparative Equilibrium Study

Abstract

Comparative experimental studies were carried out on extraction of copper(II) cations from aqueous acid nitrate media using four LIX‐reagents, representatives of different extractant classes: LIX 984N‐I, LIX 860N, LIX 84‐I and LIX 65N. As a diluent, liquid hydrocarbon undecane was used. The extraction behavior of the LIX‐reagents was compared based on an analysis of the influence of the main factors on the two‐phase mass transfer process: aqueous pH‐value, initial copper and extractant concentrations, and temperature. The experimental data received were used in the calculation of important parameters characterizing the efficiency of copper extraction from nitrate media with different LIX reagents: distribution ratios D, concentration extraction constants K _ex, pH_0.5‐values, and thermodynamic parameters such as enthalpy, entropy, and free energy changes (ΔH ⁰, ΔS ⁰, ΔG ⁰‐values).     

Wastewater Disinfection by Ozone: Influence of Water Quality and Kinetics Modeling

Wastewater disinfection by ozone was investigated at pilot scale on different effluents. The organic matter (COD and TOC) was shown to have the biggest influence on the ozone demand of the effluents. Disinfection of fecal indicators could be modeled as the reaction on a double population. The presence of more resistant microorganisms results in the need for higher treatment doses and a tertiary filtration when the effluent has to meet the stringent Title 22 standard. Eventually, the high virucidal power of ozone makes it very attractive when viruses are targeted.     

Modification of polycaproamide fibres with ethoxylated compounds. Preparation of polycaproamide with antistatic properties

Conclusions The possibility of using diethylenetriamine which has been ethoxylated to various degrees to give antistatic properties to PCA has been discussed; the antistatic effect is expressed most strongly in the case of DETA 60.It has been found that the antistatics studied exert a regulating action on the degree of polymerization of the -caprolactam, displayed in a decrease in the molecular weight of the PCA and an increase in the LMC content of the polymer. This brought about by the fact that the products examined contain, even though in slight amounts, free amino groups. DETA 100 exerts the weakest action.Under otherwise equal conditions in PCA synthesis, the introduction of DETA increase the rate of polymerization in the initial stage of the process.In view of the effects described, it is advisable, in preparing PCA fibres, to use products which contain 60 to 80 moles of ethylene oxide.Bulgaria. Translated from Khimicheskie Volokna, No. 1, pp. 42–44, January–February, 1984.