Silica content of dusts from five texas cottonseed oil mills

Total dust samples, collected with high-volume samplers, were ashed and then analyzed for aluminum, silicon and silica (SiO₂). Ash and aluminum contents agreed with earlier reported data, but the silicon content was lower. The amounts of silica ranged from 2–7% in dusts from the cleaning rooms to 0.01–0.05% in dusts from the baling rooms. Agreement with silica contents determined by infrared (IR) spectrometry was good. IR spectra indicated silica particle diameters were in the range of 6–8 µm in the cleaning rooms and 10 µm or more in the delintering and baling rooms. Threshold limit values (TLV) calculated on the basis of total silica in the high-volume samples suggest silica values above the limit in 4 of the cleaning rooms, and possibly one at the delintering rooms. Calculation of respirable silica concentrations and TLV for respirable silica was precluded by the sampling method.     

亚太地区卫星正在启用新型业务

对于直接到户(DTH)业务的提供商和其它企业家来说,亚太地区存在着新的机会:高清晰度电视(HDTV)慢慢地进入了这一地区,蜂窝电话回传、因特网协议(IP)宽带和企业领域应用正在加速。所有这些让人明白,亚太地区的各种商业机会将在未来数年里稳步增长。泰国Shin卫星公司新宽带卫星iP     

How symbolic computation boosts productivity in the simulation of partial differential equations

While there have been considerable efforts over the past 30 years to improve productivity in scientific computation through the creation of subroutine libraries, much of the mundane, error-prone work in developing simulation codes has remained. This situation has spurred the development of specialized efforts in both the numerical and symbolic computation domains. For instance, numerical software like PDECOL, L1SODE, and UNPACK will solve large classes of partial differential equations, ordinary differential equations, and linear equations, respectively. On the symbolic side of this issue, a few basic tools for developing simulation codes were created by Wirth in the late 1970s. We introduce more advanced uses of symbolic techniques, including two strategies that link the symbolic and numeric computing approaches in the context of simulation codes.     

Extrapolation of high-voltage stress measurements to low-voltageoperation for thin silicon-oxide films

Breakdown and wearout in MOS capacitors fabricated with 10 nm-thick silicon oxide films on p-type silicon are discussed. They have been stressed at high voltages. The high-voltage-stress-induced changes in the oxide properties are extrapolated to low operating voltages. The stress voltages ranged from -7.5 V to -14.5 V. The fluence during the stress was systematically varied front 2×10^-5 C/cm² to 6 C/cm² by varying the stress time at each voltage. The number of interface traps generated by the stress increased as the stress voltage and fluence increased. However, the interface trap generation rate decreased as the fluence increased. The trap generation rate at low operating voltages was very high, but because the current through the oxide was small, the total number of traps generated was low. The trap generation rate was proportional to the inverse square root of the fluence with a voltage dependence that decreased as the fluence increased. Extrapolation of the high-voltage-stress measurements to 5 V shows that easily detectable changes in the oxide properties would only occur after several years of 5 V operation. Extrapolation of charge-to-breakdown and time-to-breakdown data to 5 V operation indicates that breakdown would occur after hundreds of years of device operation     

Block acknowledgment: redesigning the window protocol

A window protocol based on the block acknowledgment method, in which acknowledgment message has two numbers, m and n, to acknowledge the reception of all data messages with sequence numbers ranging from m to n, is discussed. In the window protocol, message sequence numbers are taken from a finite domain and both message disorder and loss can be tolerated. An initial version of the protocol that uses a simplified timeout action and unbounded sequence numbers is presented, the simplified timeout action in the protocol is replaced by a sophisticated one without disturbing the protocol's correctness, and the unbounded sequence numbers are replaced by bounded ones while preserving the protocol's correctness. Remarks concerning other variations of the protocol are also presented