Pulse Combustors—Performance and Control

Limited resources of fossil energy require the search for new energy conversion processes and the increase of the efficiency of power plants to ensure the energy household in the future. Basically, changing the combustion mode from steady to pulse combustion makes an enormous reduction of fuel consumption possible. Active control systems for pulse combustors installed into the inlet further improve the efficiency and extend the operating range considerably. The control algorithm including fuel rate - air rate - pressure characteristics and control strategies as well are presented.     

Partial oxidation of n-hexadecane and polyethylene in supercritical water

In this study, we show the results of partial oxidation experiments of n-hexadecane (n-C₁₆) and polyethylene (PE) in supercritical water (SCW). The experiments were carried out at 673 or 693 K of reaction temperature and 5 or 30 min of reaction time using a 6 cm³ of a batch type reactor. Water density ranged from 0.1 to 0.52 g/cm³ (water pressure: 20–40 MPa). The loaded amount of oxygen was set to 0.3 of the ratio of oxygen atom to carbon atom. Some experiments were made using CO instead of oxygen for the partial oxidation of n-C₁₆ and PE to explore the effect of water gas shift reaction. In the results of partial oxidation of n-C₁₆, the yield of CO and some compounds containing oxygen atoms, such as aldehydes and ketones increased with increasing water density. Moreover, 1-alkene/ n-alkane ratio in the products decreased with increasing water density. The 1-alkene/n-alkane ratio was lower than that of pyrolysis in SCW. Also for the case of PE experiments, in dense SCW (0.42 g/cm³), the 1-alkene/n-alkane ratio in partial oxidation was lower than that in SCW pyrolysis. In the case of CO experiments for n-C₁₆ and PE, 1-alkene/n-alkane ratio was a little lower than that of pyrolysis in SCW. These results show that the yield of n-alkane, which is a hydrogenated compound, was higher through water gas shift reaction in SCW and also through partial oxidation in SCW. Therefore, these results suggest the possibility of hydrogenation of hydrocarbon through partial oxidation followed by the water gas shift reaction.     

Electromagnetic shielding property of laminated carbon fiber tape reinforced thermoplastics

ABSTRACT

Carbon fiber reinforced thermoplastic (CFRTP) has a good electromagnetic shielding property due to its higher conductivity and broad absorption frequency bandwidth while presenting high specific strength and stiffness, their easy process-ability, cost-effectiveness, and recyclability. In the present study, laminated CFRTP made of carbon fiber-polyamide 6 unidirectional tape (UD tape) were fabricated with different laminate configurations and arrangements (unidirectional, bidirectional, and quasi–isotropic) and then were compared with randomly chopped-tape CFRTP. Thereafter, estimated electromagnetic interference shielding effectiveness (EMI-SE) using Simon formalism and flexural properties of CFRTP were evaluated. The result showed a remarkable total EMI-SE of 31–44 dB in the Ultra High Frequency (UHF) range and strongly correlated with the laminate configuration of CFRTP. Whereas, randomly chopped-tape CFRTP has a lower total EMI-SE of 23–27 dB in the same frequency range. In addition, the flexural test result showed the flexural strength and modulus are strongly influenced by the tape layer configuration in the laminated CFRTP. Moreover, microscopy analysis was also conducted to verify the interlaminar structure and fiber-to-fiber contact in the composite. In conclusion, laminated CFRTP made of UD tape can be considered as electromagnetic interference shielding material for both functional and structural applications.     

Effect of chlorphentermine on incorporation of [14C]choline in the rat lung phospholipids

The effect of chlorphentermine (CP) treatment (50 mg/kg/ day, per os [po]) on the incorporation of [¹⁴C]choline into rat lung phospholipid was studied.Total phospholipid content was increased 2.0-fold and 1.7-fold after seven and 14 days, respectively, compared with the pair-fed rats. The incorporation of [¹⁴C]choline into phosphatidylcholine (PC) was significantly inhibited by either seven or 14 days of CP treatment. Nevertheless, the PC content was significantly increased by day 7 and stayed elevated at day 14 of CP treatment. Choline and phosphorylcholine contents were significantly decreased by the CP treatment. These results suggest that the higher accumulation of PC is due to inhibition of enzymes involved in the hydrolysis of phospholipids rather than to a stimulation of the phospholipid synthesis. Presented in part at the SOT Meeting, Atlanta, GA, March 1984 (abstracted inThe Toxicologist 4[1], 64).     

Properties and mechanisms of fast-setting calcium phosphate cements

The setting time of a calcium phosphate cement consisting of tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA) was reduced from 30 to 5 min by use of a cement liquid that contained a phosphate concentration of 0.25 mol/l or higher. The diametral tensile strength and conversion of the cement ingredients to hydroxyapatite (OHAp) during the first 3 h were also significantly increased by the phosphate. However, the phosphate produced no significant effects on the properties of the 24-h cement samples. Results from additional experiments in a slurry system verified that the high phosphate concentration in the solution accelerated the formation of OHAp in the TTCP + DCPA system, and this reaction could explain the fast-setting properties of the cements.Certain commercial materials and equipment are identified in this paper to specify the experimental procedure. In no instance does such identification imply recommendation or endorsement by the American Dental Association or National Institute of Standards and Technology or that the materials or equipment identified is necessarily the best available for the purpose.     

Model Reference Adaptive System Against Rotor Resistance Variation in Induction Motor Drive

The paper deals with a compensation method of the rotor-resistance variation in induction motor drives using high-performance slip-frequency control. Our proposed method is based on a discrete-type model reference adaptive system (MRAS), and it is implemented in an 8086 microprocessor. When an induction motor is driven by a controlled current source, the system sensitivity to the rotor resistance variation is increased. In the MRAS, the value of the rotor resistance is estimated and the slip-frequency gain is adjusted. Experimental and numerical results show that even if the value of the rotor resistance varies from its nominal value, the secondary flux level is maintained constant by using this compensation method. These results point out the validity of our proposed method.     

Ramp‐setup design technique in three‐electrode surface‐discharge ACPDPs

Abstract— A simple model to calculate changes in wall voltage during weak discharge in three‐electrode ACPDPs was developed. A change in the wall voltage vector has an intrinsic direction for each discharge, which not only reveals the basis of problems in the ramp setup but also simplifies the analysis of cell operation during setup. New ramp‐setup waveforms designed for this model widened the operating margin.     

Heat pump characteristics of sodium carbonate dehydration/hydration system

A chemical heat pump using dehydration of sodium carbonate decahydrate for generating cold heat is proposed as a method contributing to the load leveling of electricity. Experiments on the dehydration of decahydrate in a packed bed reactor showed the generation of cold heat with sufficiently low temperature. The heat pump characteristics measured were simulated by use of dehydration kinetics of a single particle. Improvement of the heat-transfer rate in the bed is a key factor for creating an efficient system.