Land surface temperature derived from the SSM/I passive microwavebrightness temperatures

Passive microwave brightness temperatures from the Defense Meteorological Space Program Special Sensor Microwave/Imager (SSM/I) were used to determine surface temperature over land areas in the central plains of the United States. A regression analysis comparing all of the SSM/I channels and minimum screen air temperatures (representing the surface temperature) showed good correlations, with root-mean-square errors of 2-3 degC. Pixels containing large amounts of water, snow, and falling rain, as classified with SSM/I brightness temperatures, were excluded from the analysis. The use of independent ground truth data such as soil moisture or land surface type was not required to obtain the correlations between brightness temperatures and surface temperatures     

Contribution of flow deformation to the shrinkage of injection molded PVC

The viscoelastic nature of PVC cannot be ignored during the injection molding process. Strains imposed on the compound during the injection stage display recovery dynamics that are indicative of the temperature at which the strains were imposed. A mathematical model, employing “approximate” time-temperature modulus relationships, provided the basis for interpreting the shrinkage data. A distribution map of the various relative temperatures attained within the part during injection was determined.     

Numerical Performance Simulation of a Wetted Wall Bioaerosol Sampling Cyclone

Computational fluid dynamics techniques are used to study the performance of an axial flow bioaerosol sampling cyclone that continuously collects particles onto a flowing liquid film. A special shell-volume concept was developed to study formation and development of the liquid film on the inner wall of the cyclone. For a previous version of the cyclone, simulations demonstrated the presence of a ring of liquid in the region just upstream of the liquid skimmer that was suspected of causing liquid carryover into the exhaust air stream and degradation in aerosol collection efficiency. This ring was eliminated by re-design of the cyclone. For the upgraded version of the cyclone, CFD was used to successfully predict aerosol collection efficiency and cyclone pressure drop. The simulations reveal a complex flow evolution inside the cyclone. Stream-tubes are used to describe a significant narrowing of the width of the airflow as it enters the cyclone and an inward displacement of the flow as it travels in the axial direction. The particle deposition occurs primarily in a region that is subtended approximately by the length of the rectangular entrance slot and the first half turn of the flow in the cyclone. Cutpoint Stokes number is about 0.05 and the cutpoint particle size is about 1 μm aerodynamic diameter. At a flow rate of 1250 L/min, the pressure drop across the cyclone is 5.6 kPa (22 inches of water).     

An Aerosol Wind Tunnel for Evaluation of Massive-Flow Air Samplers and Calibration of Snow White Sampler

Massive-flow air samplers are being deployed around the world to collect aerosol samples for analysis of radioactivity as a result of nuclear tests and nuclear accidents. An aerosol wind tunnel capable of an 1100 m³ min^?1 flow rate was built at Lovelace Respiratory Research Institute (LRRI) to test the sampling efficiency of these samplers. This aerosol wind tunnel uses a stationary air blender to enhance mixing, and therefore it achieves the required uniform distribution of wind speed and aerosol concentration in the test section. The test section of the wind tunnel has a cross section that is 4.3 m × 3.7 m. The aerosol wind tunnel was tested for performance in terms of distribution of wind speed, turbulent intensity, SF₆ tracer gas concentration, and aerosol concentration. Test criteria consistent with U.S. Environmental Protection Agency (EPA) and American National Standards Institute (ANSI) standards were adopted as the guidelines for the aerosol wind tunnel. Additional criteria for aerosol wind tunnel were also recommended. Initial test of the aerosol wind tunnel showed that the wind tunnel could be operated in a wind speed range of 2 to 24 km h^?1. Within this range, the distribution of wind speed SF⁶ trace gas concentration and aerosol concentration in two-thirds of the central area of the test section showed coefficient of variances (COVs) of less than 10% for the range of wind speeds. This met the stringent guidelines for aerosol wind tunnel performance set by EPA and ANSI standards.

The LRRI wind tunnel was used to evaluate the collection efficiency of the sampling head of massive-volume air samplers, including the Snow White sampler. The sampler was tested in this aerosol wind tunnel for particles between 2 and 20 μm. The sampling flow rates were 500 and 700 m³ h^?1 for the tested wind speeds of 2.2 and 6.6 m S^?1, respectively. The results showed that sampling efficiency was influenced by both sampling flow rate and wind speed. The sampling efficiency decreased with an increase in particle size of between 2 and 20 μm. The sampling efficiency also decreased as the wind speed was increased from 2.2 to 6.6 m S^?1.     

Liquid Consumption of Wetted Wall Bioaerosol Sampling Cyclones: Characterization and Control

Advances in microfluidic, lab on chip, and other near-real-time biological identification technologies have driven the desire to concentrate bioaerosols into hydrosol sample volumes on the order of tens of microliters (μL). However, typical wet biological aerosol collector outputs are an order or two of magnitude above this goal. The ultimate success of bioaerosol collectors and biological identifiers requires an effective coupling at the macro-to-micro interface. Liquid collection performance was studied experimentally for a family of dynamically scaled wetted wall bioaerosol sampling cyclones (WWC's). Steady-state liquid collection rates and system response times were measured for a range of environmental conditions (temperatures from 10°C to 50°C and relative humidities from 10% to 90%), liquid input rates, and WWC airflow configurations. A critical liquid input rate parameter was discovered that collapsed all experimental data to self-similar empirical performance correlations. A system algorithm was then developed from empirical correlations to provide control over the liquid output rate and resulting concentration factor for a cyclone with an airflow rate of 100 L/min. Desired liquid output rates of 25 to 50 μL/min were maintained while sampling outdoor air over diurnal ranges of environmental conditions. These flow rates are associated with concentration factors on the order of 1,000,000 to 2,000,000 and liquid outputs that are a steady stream of 10 to 30 drops/min of 7 to 10 μL droplets. These developments should allow wetted wall cyclones to be effectively coupled to advanced biological identification systems.     

The language of demand/withdraw: Verbal and vocal expression in dyadic interactions.

Associations between vocally expressed emotional arousal, influence tactics, and demand/withdraw behavior were examined in a treatment-seeking sample of 130 seriously and stably distressed, married, heterosexual couples and in a community sample (N = 38) of 18 married heterosexual and 20 dating heterosexual couples. Fundamental frequency was used to measure emotional arousal, and computational linguistics were used to measure influence tactics. Higher levels of demand/withdraw behavior were associated with greater use of manipulative and controlling influence tactics, higher levels of emotional arousal, and less frequent use of cooperative and compromising influence tactics. Overall, demanders tended to express more arousal and to use more influence tactics than withdrawers. Both influence tactics and emotional arousal were uniquely associated with demand/withdraw behavior. Implications of results are discussed for refining theories of demand/withdraw interaction. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

基于Windows下Modem软件研究与设计

本文研究了Windows操作系统下I／O端口应用问题，用VC^ 6．0嵌入汇编语言技术，为“远传水表系统”项目开发了Modem通讯软件，并给出了部分实现函数。实践表明，软件运行良好。