Experimental study on principles of isothermal dehydration of anthracite

Isothermal dehydration experiments were performed and studied on anthracite. A mathematical model is established for anthracite dehydration to improve the efficient utilization of high-moisture anthracite exploited by water addition technology. Three kinds of high-moisture anthracite with different particle size were treated by isothermal drying methods. Experimental results show that there are two clear stage differentiations in the derivative thermogravimetric curve of the anthracite drying process, namely X_c1 and X_c2. The dehydration process can be divided into the rapid deceleration phase (X?<?X_c1), the steady linear dehydration phase (X_c1?<?X?<?X_c2), and the deceleration phase (X?>?X_c2). The drying mechanisms of the three dehydration stages are different. When X?>?X_c2, the evaporation of the free water and bound water in the large pore of the anthracite is influenced by the capillary force of the curved liquid surface. When X_c1?<?X?<?X_c2, the main driving force of water migration is the pressure gradient. When X?<?X_c1, the detached water partly comes from the internal micropores of the anthracite and the rest is connected with the functional groups of the anthracite surface. A high drying temperature contributes to increasing the drying rate of the drying process, thereby improving the effects of anthracite dehydration.     

一种新的齿轮啮合效率计算方法探讨

在对平面高副机构传动效率的通用计算公式分析的基础上，推导出了一种新的齿轮传动装置的啮合效率的计算公式，并对该公式的正确性做了验证。     

The use of ion exchange resins for the treatment of cyanidation tailings part 1––process development of selective base metal elution

This work investigates the use of oxidative acid eluents for the elution of base metals from strong base ion exchange resins. Eluents composed of a mixture of H₂O₂ and H₂SO₄ were tested for eluting base metals from resins loaded with mixtures of base and precious metal cyanides. This process removed 100% of Cu and Zn loaded on the resin, without affecting the precious metal loading. It was found that copper could be removed separately from the other base metals. The elution technique was not effective for removing iron from the resin. Cyanide associated with base metals was recovered as NaCN. Some oxidation of cyanide was noticed, subject to the elution conditions.This oxidative acid elution process could be used in commercial operations for the selective elution of base metals from a strong base ion exchange resin bed operating in alternative adsorption/base metal elution cycles. Thus, virtually all metal cyanide species could be recovered from cyanide leached solutions or slurries to give relatively clean tailings without compromising precious metal recovery efficiency. The process also caters for cyanide recovery and recycling.     

Brachially innervated ectopic hindlimbs in the chick embryo. I. Limb motility and motor system anatomy during the development of embryonic behavior

The functional status of brachially innervated hindlimbs, produced by transplanting hindlimb buds of chick embryos in place of forelimb buds, was quantified by analyzing the number and temporal distribution of spontaneous limb movements. Brachially innervated hindlimbs exhibited normal motility until E10 but thereafter became significantly less active than normal limbs and the limb movements were more randomly distributed. Contrary to the findings with axolotls and frogs, functional interaction between brachial motoneurons and hindlimb muscles cannot be sustained in the chick embryo. Dysfunction is first detectable at E10 and progresses to near total immobility by E20 and is associated with joint ankylosis and muscular atrophy. Although brachially innervated hindlimbs were virtually immobile by the time of hatching (E21), they produced strong movements in response to electrical stimulation of their spinal nerves, suggesting a central rather than peripheral defect in the motor system. The extent of motoneuron death in the brachial spinal cord was not significantly altered by the substitution of the forelimb bud with the hindlimb bud, but the timing of motoneuron loss was appropriate for the lumbar rather than brachial spinal cord, indicating that the rate of motoneuron death was dictated by the limb. Measurements of nuclear area indicated that motoneuron size was normal during the motoneuron death period (E6-E10) but the nuclei of motoneurons innervating grafted hindlimbs subsequently became significantly larger than those of normal brachial motoneurons. Although the muscle mass of the grafted hindlimb at E18 was significantly less than that of the normal hindlimb (and similar to that of a normal forelimb), electronmicroscopic examination of the grafted hindlimbs and brachial spinal cords of E20 embryos revealed normal myofiber and neuromuscular junction ultrastructure and a small increase in the number of axosomatic synapses on cross-sections of motoneurons innervating grafted hindlimbs compared to motoneurons innervating normal forelimbs. The anatomical data indicate that, rather than being associated with degenerative changes, the motor system of the brachial hindlimb of late-stage embryos is intact, but inactive.     

Solid media thermal storage for parabolic trough power plants

For parabolic trough power plants using synthetic oil as the heat transfer medium, the application of solid media sensible heat storage is an attractive option regarding investment and maintenance costs. In the project WESPE that is described in this paper, solid media sensible heat storage materials have been researched. Two storage systems with a storage capacity of about 350 kW h each and maximum temperatures of 390 °C have been developed. The test storage units of WESPE are erected at the Plataforma Solar de Almeria in Spain. The thermal energy is provided by a parabolic trough loop with a maximum thermal power of 480 kW. The first tests were performed at storage temperatures up to 325 °C by March of 2004; testing will be continued during 2004 to achieve the nominal operation conditions of 390 °C and to gain experience for long term behaviour. These storage systems are composed of modules with two different storage materials to identify the characteristics of these materials. A tubular heat exchanger is integrated into the storage material. This heat exchanger demands a significant share of the investment costs. The selection of geometry parameters like tube diameter and number of tubes therefore play an important role in the optimisation. The design of the WESPE test module is based on results provided by a numerical tool for simulation of the transient performance of storage systems.     

Rotating waves in rings of coupled oscillators

In this paper we discuss the types of stable oscillation created via Hopf bifurcations for a ring of identical nonlinear oscillators, each of which is diffusively and symmetrically coupled to both its neighbours, and which, when uncoupled, undergo a supercritical Hopf bifurcation creating a stable periodic orbit as a parameter, λ is increased. We show that for small enough coupling, the only stable rotating waves produced are either one or a conjugate pair, depending on the parity of the number of oscillators in the ring and the sign of the coupling constant, and that the magnitude of the phase difference between neighbouring oscillators for these rotating waves is either zero (i.e. the oscillators are synchronized) or the maximum possible, depending on the sign of the coupling constant. These brances of rotating waves are produced supercritically.     

Molecular lysis of synovial lining cells by in vivo herpes simplex virus-thymidine kinase gene transfer

Herpes simples virus thymidine kinase (HSV-TK) expression plasmid DNA was injected into the joint space of rabbits with antigen-induced arthritis (AIA). Purified plasmid DNA was able to mediate transfection of synovial lining cells and transient overexpression of HSV-TK in the context of active synovial inflammation. The pharmacodynamic distribution of intraarticular expression plasmid DNA was confined to the joint space. Arthritic rabbits treated with intraarticular expression plasmid DNA followed by intravenous ganciclovir (GCV, 5 mg/kg) twice daily for 3 days showed histologic evidence of synovial lining layer cytolysis when articular tissues were examined 21 days posttreatment. There was also a reduction in joint swelling in the TK-treated knees. No untoward clinical effects were observed in the rabbits and no evidence of cytolytic damage specific to the TK-GCV gene therapy was observed either in the articular cartilage or bone. The application of TK-GCV intraarticular gene therapy using purified expression plasmid DNA for the induction of synovial cytolysis may be applicable to the treatment of human inflammatory arthritis.