A Theoretical Study on a Series of Alkylamines on Silica

Silica surface covered with silanols round PZC detaches protons from the surface in alkaline ranges to increase surface negative charges of oxygen. The charge distributions of nitrogen of aminium ions are neutral, while those of amine molecules are negative. The positive charges of hydrogen connected to nitrogen of the aminium ions become greater than those of the amine molecules. The interaction between amines and silica is mainly coulombic. The bonds between amines and silica are almost the same as, or less in strength, than the hydrogen bond of a water dimer. The aminium ions are easy to adsorb on silica in alkaline ranges rather than round PZC. Both the aminium ion and the amine molecule prefer to adsorb on silica energetically by exchanging water molecules and sodium ions existing in the diffuse layer, or on the double layer. A series of aminium ions is easier to adsorb on silica as the chain length of the alkyl group becomes longer. The stabilization energy of the adsorption of a series of aminium ions is theoretically evaluated 0.25 kT per CH₂ group

On the Critical Flotation Condition of a Sulfide Mineral Having Two Kinds of Positive Sites for the Anionic Collector and Depressant Adsorption

The critical flotation condition for the sulfide mineral having two kinds of positive sites was discussed from the viewpoint of the competitive adsorption of anionic collectors and depressants by means of statistical mechanics and chemical thermodynamics. On the basis of the statistical mechanics as to the collector-depressant equilibria, the familiar Barsky relation was derived for the double positive site mineral. The Barsky constant can be dependent on all of the collector and depressant adsorptions for each kind of reaction site on the mineral surface according to their adsorption property. In the chemical thermodynamics investigation, the chalcopyrite (CuFeS₂)-xanthatehydroxyl ion system was considered. The chemical affinities of the xanthate ion and the hydroxyl ion onto the positive sites of CuS and FeS, respectively, were calculated, using thermodynamical data for the system. Consequently, it was ascertained that the depressing action of the hydroxyl ion for chalcopyrite was mainly connected with the adsorption of the hydroxyl ion onto the positive site due to FeS, while the collecting mechanism of the xanthate ion for the same mineral is closely related to the adsorption of the xanthate ion onto the positive site due to CuS. The chalcopyrite (CuFeS₂)-xanthate-cyanide ion and hydroxyl ion system was also considered in a similar manner. The flotation-nonflotation condition of chalcopyrite was able to be determined by considering the xanthate adsorption on the positive site due to CuS and the cyanide ion adsoprtion on the one due to FeS

Mutual Interaction between Collectors and Frothers in Flotation

The behavior of a frother in flotation was investigated from the viewpoint of the mutual interaction between a collector and a frother. The floatability of galena and the interfacial tensions of the mercury-solution interface were measured using ethyl and amyl xanthates and normal alcohols containing 1～5 carbon atoms. The floatability test showed that butyl and amyl alcohols were favourable as a frother. The interfacial tension mesurements verified that alcohol molecules can adsorb on the mercurysurface only in coexistence with xanthate molecules in a solution. The degree of the coadsorption of alcohol molecule with xanthate molecule on mercury increases with increasing the number of carbon atoms in the alkyl chain of alcohol. It was clarified from the discussion of the infrared-spectroscopic study for the reagents that the value of ln(ν-ν₀) based on the shift of CH₃ stretching vibration was closely related to the degree of the coadsorption of a frother with a collector at the mineral-solution interface. Furthermore, the value of ln (ν－ν₀) was shown to be one of the measures indicating the choice of their proper combination

High-Voltage Methods for Mushroom Fruit-Body Developments

High-voltage electrical stimulation is effective for promotion of fruit-body development in mushroom cultivation. The high voltage applying to cultivation bed of mushroom generates intense electric field inside the bed substrate. The intense electric field accelerates the hypha move owing to the electrostatic force. As a result, some parts of hyphae are cut and scratched. The cutting and scratching of hypha work as stimulation for promotion of the fruit-body development. The promotion effect of high-voltage stimulation to sawdust-based substrate of L. and natural logs hosting Lentinula edodes, Pholiota microspora and Hypholoma lateritium are confirmed through the experiment in the cultivation field. The fruit-body formation of mushrooms increases 1.3–2.0 times in terms of the total weight. The accumulated yield of L. edodes for four cultivation seasons is improved from 160 to 320 g by applying high voltage of 50 or 100 kV. However, the yield decreases from 320 to 240 g upon increasing applied voltage from 100 to 130 kV. The yield of the other types of mushrooms shows tendencies similar to those of L. edodes by applying high voltage. An optimal voltage exists for efficient fruiting body induction

A State-Space Modeling via the Galerkin Approximation for a Boundary Control System

For linear distributed parameter systems with a finite number of boundary inputs, we propose a framework to implement the method of weighted residuals using candidate trial functions without boundary homogenization. Proposed scheme utilizes inner product matrix, or Grammian, of the trial functions to separate appropriate homogenized basis functions and the other trial functions matching inhomogeneous boundary conditions. The finite-dimensional approximate model by using the proposed scheme is represented in descriptor form and it is proved to be straightforwardly transformed into state space form. Feasibility of the method is illustrated by a brief controller design example using the approximate model of a heat conduction rod with Dirichlet boundary input

A Novel Wastewater Treatment Method Using Electrical Pulsed Discharge Plasma over a Water Surface

Electrical pulsed discharge plasma produces various powerful oxidizing agents, such as hydroxyl radicals and ozone, which have high oxidation potential. These species play an important role in the decomposition of persistent organic compounds in wastewater. Because highly concentrated oxidants are directly produced inside the plasma, plasma realizes high-speed wastewater treatment without pretreatment of samples, such as pH adjustment. The pulsed discharge plasma generated over the water surface and inside bubbles is highlighted as a highly efficient method for plasma generation and radical supply into wastewater. In this paper, the physical and chemical properties of the discharge plasma generated over a water surface are described. The decomposition of persistent organic compounds dissolved in wastewater, such as 1,4-dioxane, formic acid, and dichloromethane, by plasma discharge is demonstrated, and their mechanisms are discussed. These persistent compounds, which have strong toxicity and stability, can be efficiently decomposed and removed quickly from solutions by plasma treatment. Furthermore, the treatment of nutrient solutions used in hydroponic systems for plant cultivation is also introduced as a novel application of plasma, and the effects of bacterial inactivation, decomposition of allelochemicals, and improvement in plant growth by plasma are demonstrated

Influence of oxygen in inflation gas during lung ischemia on ischemia-reperfusion injury

AbstractObjectives: Previous studies have reported that hyperinflation during lung ischemia improves pulmonary function after reperfusion. However, it has not been clarified whether hyperinflation itself or oxygen in inflation gas causes good pulmonary function. The aim of this study is to evaluate the effect of oxygen in pulmonary inflation gas during lung ischemia on ischemia-reperfusion injury. Methods: Twenty-one mongrel dogs were randomly divided into three groups: the lung during a 90-minute period of warm ischemia was inflated to 30 cm H2O with 100% oxygen in group A and 100% nitrogen in group B; it was not inflated in group C. Pulmonary function and hemodynamics were measured before ischemia and 1,2, and 3 hours after reperfusion. Total protein and phosphorous of phospholipid in bronchoalveolar lavage fluid were measured 210 minutes after reperfusion. Results: No significant differences in pulmonary function and hemodynamics were noted between group A and group B, but these two groups had significantly better pulmonary function and hemodynamics than group C. No significant differences were detected in the concentrations of total protein and phosphorus of phospholipids in bronchoalveolar lavage fluid and in adenine nucleotide levels of lung tissue after reperfusion among the three groups. Conclusions: The results indicate that pulmonary inflation during warm ischemia improves pulmonary function and hemodynamics after reperfusion in this model. The effect is caused by inflation itself and is not due to oxygen as a metabolic substrate during warm ischemia. (J Thorac Cardiovasc Surg 1997;114: 332-8

Development of a Corona Discharge Ionizer Utilizing High-Voltage AC Power Supply Driven by PWM Inverter for Highly Efficient Electrostatic Elimination

The corona discharge ionizer has been widely used to eliminate electrostatic charges on insulators in a variety of manufacturing industries for the prevention of electrostatic discharge (ESD) problems. High-speed electrostatic elimination is conventionally required for ionizer performance. Because of the high sensitivity of recent electronic devices to ESD damage, an extremely low-offset voltage (ion balance) is required for the performance of electrostatic eliminators. Long-term performance stability is required to maintain the quality of the products, but the short cleaning interval of the unit increases the operating cost. The efficiency is also affected by the waveform of the applied voltage. The optimization of the applied voltage is an important factor in achieving long-term performance stability. In this study, an intermittent pulse voltage AC power supply was developed to achieve a highly efficient electrostatic elimination with long-term stability high-speed electrostatic elimination and an excellent ion balance

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早大学位記番号:新8527早稲田大