High-performance 980-nm strained-layer GaInAs-GaInAsP-GaInP quantum-well lasers grown by all solid-source molecular-beam epitaxy

High-performance strained-layer GaInAs-GaInAsP-GaInP separate-confinement quantum-well lasers emitting at /spl lambda/=980 nm were grown by all solid-source molecular-beam epitaxy. Valved cracker cells were employed to generate group-V beam fluxes. Fabricated ridge-waveguide lasers exhibited stable, kink-free, single-mode operation up to 260 mW. A maximum output power of 550 mW was achieved. Complete thermal roll-over tests were done tens of times without any sign of degradation for p-side up-mounted lasers. Preliminary lifetime tests for over 4500 h at 150-mW power level indicate that these aluminum-free pump lasers are very reliable sources for pumping light into erbium-doped fiber amplifiers.     

Glutamate-stimulated ROS production in neuronal cultures: interactions with lead and the cholinergic system

Oxidative stress may be an important factor in several pathological brain conditions. A contributing factor in many such conditions is excessive glutamate release, and subsequent glutamatergic neuronal stimulation, that causes increased production of reactive oxygen species (ROS), oxidative stress, excitotoxicity and neuronal damage. Glutamate release is also associated with illnesses such as Alzheimer's disease, stroke, and brain injury. Glutamate may interact with an environmental toxin, lead, and this interaction may result in neuronal damage. Glutamate-induced ROS production is greatly amplified by lead in cultured neuronal cells. Alterations in protein kinase C (PKC) activity seem to be important both for glutamate-induced ROS production, and for the amplification of glutamate-induced ROS production by lead. It is possible that the neurotoxic effects of lead are amplified through glutamate-induced neuronal excitation. Cholinergic stimulation can also trigger ROS production in neuronal cells. PKC seems to play a key-role also in cholinergic-induced ROS production superoxide anion being the primary reactive oxygen species. There seems to be a close relationship between the responses of cholinergic muscarinic and glutamatergic receptors because glutamate receptor antagonists inhibit cholinergic-induced activation of human neuroblastoma cells. Glutamatergic neuronal stimulation may be a common final pathway in several brain conditions in which oxidative stress and ensuing excitotoxicity plays a role.     

Altered transfer of cholesteryl esters and phospholipids in plasma from alcohol abusers

The net mass transfer (NMT) of cholesteryl esters (CEs), triglycerides (TGs), and phospholipids (PLs) between lipoproteins was measured after incubation of fresh plasma for up to 2 hours from 18 male alcohol abusers and 17 male volunteer control subjects. In alcohol abusers the mean value of CE NMT was 3.7 nmol.mL-1.h-1 from apolipoprotein B-containing lipoproteins (apoB-containing lipoproteins) to HDL and in control subjects 8.7 nmol.mL-1.h-1 from HDL to apoB-containing lipoproteins. The NMT of PL was higher in alcohol abusers than in control subjects (35.0 vs 11.6 nmol.mL-1.h-1 from apoB-containing lipoproteins to HDL, respectively), and plasma PL transfer protein (TP) activity was 33% higher (P < .05) in alcohol abusers than in control subjects. The lack of correlation between the NMTs and CETP and PLTP activities suggests that the NMT could more closely reflect the role of lipoprotein properties in reverse cholesterol transport in vivo, whereas in vitro activities reflect the total capacity of transfer but not its direction. The rate of CE NMT from HDL to apoB-containing lipoproteins was dependent on the VLDL TG concentration. Moreover, at low VLDL TG levels, the increased HDL cholesterol concentration in alcohol abusers reversed the direction of CE NMT. This situation could be reconstructed in the plasma of control subjects by adding autologous HDL or VLDL to mimic the lipoprotein profiles of the alcohol abusers. Addition of VLDL enhanced the CE NMT from HDL to apoB-containing lipoproteins, whereas addition of HDL had an opposite effect, and at higher HDL levels, even reversed the direction of CE NMT. In conclusion, the NMT of CE and PL in alcohol abusers differs from that in control subjects. The concentrations of HDL and VLDL seem to be the major determinants of the direction of CE NMT in alcohol abusers.     

Co-firing of biomass in coal-fired utility boilers

Co-firing tests with sawdust and coal have been carried out at FORTUM's Naantali-3 CHP power plant (315 MW_fuel). The Naantali-3 plant is a tangentially-fired pulverised-coal unit with a Sulzer once-through boiler that produces 79 MW electricity, 124 MW district heat and 70 MW steam. Naantali-3 is equipped with roller coal mills (Loesche), modern low-NO_x-burners (IVO RI-JET), over-fire air (OFA), electrostatic precipitator (ESP) and flue-gas desulphurization plant (FGD). Coal and sawdust were blended in the coal yard, and the mixture fed into the boiler through coal mills. Tests were carried out for three months during the April 1999 to April 2000 period with pine sawdust (50-65% moisture as received). During the tests, sawdust proportions of 2.5–8% (from the fuel input) were examined. The co-firing tests were successful in many ways, but the behaviour of the coal mills caused some problems, and therefore the simultaneous feed will not be the solution in a long-term use. Fortum has developed a new concept for co-firing coal and biofuels in large pulverised-coal fired boilers. The experiences gained from the Naantali co-firing tests and a good knowledge of low-NO_x burning and combustion behaviour of different fuels at Fortum, was used when the new co-firing concept was developed. This concept consists of a separate biofuel grinding system and bio- or bio-coal-burners. By using this system, it is possible to utilize many kinds of biofuels in PC-boilers as well as increase the share of biofuels, compared to the simultaneous feed of biofuel and coal.     

Purification process for recovering hydroxy acids from soda black liquor

Black liquor, a side product of chemical pulping, contains hydroxy acids that have many potential applications, e.g., as polymer precursors. Currently there are no feasible separation processes available for recovery of hydroxy acids from such solutions. Neutralization is usually though to be a necessary pre-treatment, but it adds into chemical consumption and may impede the integration of the recovery process to a pulp mill. In this work, an experimental investigation of a new process concept for the recovery and purification of hydroxy acids from soda black liquor without neutralization is presented. The process consists of ultrafiltration, size-exclusion chromatography, ion-exchange, adsorption, and evaporation. Mixtures of hydroxy acids in high purity were produced from black liquor of soda pulping using the process. A reduction of 99% in lignin content of the organic acid fraction was achieved. In the chromatographic separation step, the recovery of sodium hydroxide was almost 100%. The average purities of hydroxy acids isolated from softwood and hardwood black liquors were 81% and 63% on mass basis, respectively.     

MIMO Detector for LTE/LTE-A Uplink Receiver

Journal of Signal Processing Systems - We propose a carefully selected receiver structure, detector and detector implementation architecture for multiple-input multiple-output (MIMO) uplink base...     

Electromagnetic and mechanical design aspects of a high-speed solid-rotor induction machine with no separate copper electric circuit in the megawatt range

The most crucial electro-magnetic and mechanical design aspects of an integrated electrical-motor–gas-compressor system in high speed and high power operation are presented. The electric motor type considered is a solid-rotor induction motor with properties of which are particularly well suited in high-speed operation. The effect of the electro-magnetic material properties of the solid rotor core material on the performance of the machine is discussed. Guidelines to improve the performance of the solid-rotor induction motor are given. Thermal design aspects of a solid-rotor induction motor are presented. The mechanical properties of a solid rotor are discussed. Bearing arrangements as well as the rotor dynamics of an integrated system are presented.     

Incorporating Hydrologic Uncertainty in Industrial Economic Models: Implications of Extreme Rainfall Variability on Metal Mining Investments

Water balance uncertainties have long been known to lead to potential environmental hazards, but their effect on economic profitability of mines is an under-studied field of research. Historical rainfall data are analyzed using the extreme value theory (EVT) and the peak over threshold method (POT). The resulting distributions are used as inputs into a system dynamics techno-economic metal mining investment profitability model, and simulation analysis is performed. The proposed methodology incorporates rainfall extremes and uncertainty into techno-economic modeling of metal mining operations. A case study with real-life historical rainfall data was used to illustrate the relationship between hydrologic uncertainty and the economic value of a metal mining investment.

     

多层柔性衬底电路板的低成本丝网印刷

当大批量生产多层聚合物基厚膜电路板时需要低成本的印刷技术.对于有超过6层导电层且不平滑的表面来说,丝网印刷是一个便宜、便捷的选择.为了研究丝网印刷技术的可行性,本研究在不同衬底材料的表面,如聚碳酸酯(PC)、聚酯(PET)、聚酰亚胺(PI)和液晶聚合物(LCP),使用同样的印刷分辨率,常规的厚膜网版印刷,通过丝网的网孔在衬底上形成精细图形.最后,研究在双层PI衬底(拥有2层导体层,在导体层的两侧有1层绝缘层覆盖板基孔)上的印刷.丝网印刷的导体材料是银基纳米颗粒油墨,介质层是聚酰亚胺基材料.许多变量是妨碍这种经济适用技术大规模生产应用的影响因素.例如,如果固化温度超过200℃,聚酰亚胺基板的稳定性就成为大问题.在本实验中,如果印刷面积小,层与层之间的对齐公差是允许的.然而,在印刷进行一段时间后,层与层之间的平整度会变差.测试用纳米粒子油墨是一种很好的导电系统,但是,当固化温度从230℃降低到200℃时,生产效率会受到极大影响.另一种实现多层结构的方法是层压法.本研究选择PET和PC层,重点是处理沉积胶层的PET层和片材的复合过程.多层结构中的板基孔和导线通过常规厚膜网印解决.先打孔,然后采用厚膜网印填补,最后印刷表面.层与层之间的黏合精度和对准精度<±15μm.