Observation of Coalescence Process of Silver Nanospheres During Shape Transformation to Nanoprisms

In this report, we observed the growth mechanism and the shape transformation from spherical nanoparticles (diameter ~6 nm) to triangular nanoprisms (bisector length ~100 nm). We used a simple direct chemical reduction method and provided evidences for the growth of silver nanoprisms via a coalescence process. Unlike previous reports, our method does not rely upon light, heat, or strong oxidant for the shape transformation. This transformation could be launched by fine-tuning the pH value of the silver colloidal solution. Based on our extensive examination using transmission electron microscopy, we propose a non-point initiated growth mechanism, which is a combination of coalescence and dissolution–recrystallization process during the growth of silver nanoprisms.     

Leading fire signatures of spacecraft materials: Light gases, condensables, and particulates

The primary goal of this research is to provide recommendations for the eventual development of more effective and efficient fire sensors to be installed in space vehicles and habitats. An entirely new ground-based testing facility that generated fire signatures was developed to perform the combustion and pyrolysis experiments of eight different practical spacecraft materials. The flaming and smoldering of polymers approved by the National Aeronautics and Space Administration (NASA) generate three types of residues: condensables, light gases, and particulates. The residues were characterized by gas chromatography (GC), Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). The analysis was interpreted as a function of oxygen concentration, temperature, and flow direction. Key findings are that the combustion of some materials such as Kevlar and cotton can only be identified by light gases, while the combustion of other materials, such as silicone and melamine, is best detected using a particulate-specific sensor. The implications during a fire event, its suppression, astronaut health in post-event cleanup as well as material recommendations are briefly discussed.     

Prediction of polymer tube life for solar hot water systems: A model of antioxidant loss

The successful use of polymer components in solar hot water systems requires an understanding and method of predicting material degradation in water. The relevant degradation mechanism is oxidation. Degradation from oxidation can be delayed through the use of antioxidant additives. However, once the antioxidants have been depleted, oxidation of the polymer and subsequent loss of mechanical integrity occur rapidly. In this study, antioxidant loss from polymer tubes is modeled. Dimensional analysis and results of the model show the rate of antioxidant loss is controlled by diffusion through the polymer. The diffusion time scale is dictated by the tube wall thickness. Antioxidant concentration profiles and depletion rates are presented for three representative tube geometries and temperatures of 293 and 333 K. The time to deplete 90% of the antioxidant is on the order of 1000–10,000 h.     

Level of processing as a determinant of hypnotic hypermnesia.

Reconceptualized the distinction between those situations in which one can and cannot expect to observe hypnotic hypermnesia using the levels-of-processing theory of memory, as proposed by F. I. Craik and R. S. Lockhart (see record 1973-20189-001). In Study 1, 20 hypnotized Ss (high hypnotizables), relaxed/motivated Ss (high hypnotizables), and 20 simulating Ss (low hypnotizables) processed lists of words matched for meaningfulness and imagery value at "deep" or "shallow" levels. As predicted, the hypnotized group recalled more deeply but not more shallowly processed stimuli than the control groups. In Study 2, these findings were replicated with 30 undergraduates using improved experimental procedures and were extended to a recognition situation. In neither study was the observed hypnotic enhancement accompanied by an increment in errors. It is concluded that cognition at the time of processing is critical in rendering a stimulus amenable to hypnotic hypermnesia. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sterile Filtration of NanoCrystal™ Drug Formulations

A Nano Crystal^TM dispersion of the iodinated x-ray contrast agent iodipamide was prepared by wet milling the drug substance in the presence of Pluronic® F127 stabilizer. The mean particle size of the formulation was 98 nm and all drug particles in the formulation were smaller than 220 nm as determined by dynamic light scattering. Approximately 1 liter of dispersion was filtered through a sterile 0.2-μm disposable capsule filter (Supor® 200 DCF^TM, 0.I m² effective filtration area [EFA], Gelman Sciences) to condition the capsule. No drug concentration or size distribution changes were detected after the filtration process. The microbiological validation tests were performed using Pseudomonas diminuta organisms to challenge the capsule under simulated worst-case process conditions. The results showed that the Supor 200 DCF was able to retain 100% Pseudomonas diminuta organisms (≥10⁷ organisms per cm² of effective filtration area). Thus, this study demonstrated that terminal filtration is a feasible process to sterilize Nano Crystal^TM drug dispersions that may be chemically or physically unstable at elevated temperatures and thus not amenable to terminal heat sterilization.     

On the autonomy of mental processes: A case study of arithmetic.

Defined a process as autonomous (a) if it can begin without intention and (b) if it can run on to completion without intention. Empirical criteria were developed for determining whether a process can begin without intention, for determining whether it begins in the same way without intention as it does with intention, and for determining whether it can run on to completion without intention once it begins. These criteria were applied to assess the autonomy of the processes underlying simple mental arithmetic (the addition and multiplication of single digits) in 6 experiments with 176 undergraduates. Findings indicate that simple arithmetic may be only partially autonomous in that it can begin without intention, but it does not begin in the same way without intention as with intention and does not run on to completion without intention. It is suggested that there may be a continuum of autonomy, ranging from completely autonomous to completely nonautonomous. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Power consumption benchmark for a semiconductor cleanroom facility system

Benchmarking is an important step in implementing energy conservation in a semiconductor fabrication plant (hereafter referred to as “fab”). A semiconductor cleanroom facility system is complicated, usually comprised of several sub-systems, such as a chilled water system, a make-up system, an exhaust air system, a compressed air system, a process cooling water (PCW) system, a nitrogen system, a vacuum system, and an ultra-pure water (UPW) system. It is a daunting task to allocate energy consumption and determine an optimum benchmark. This study aims to establish the energy benchmark of a typical 8-in. DRAM semiconductor fab through field measurement data. Results of the measured energy consumption index were: chilled water system (including chiller, chilled water pump and cooling tower): 0.257 kW/kW (=0.9 kW/RT) in summer and 0.245 kW/kW (=0.86 kW/RT) in winter air recirculation air system: 0.00018 kWh/m³ make-up air system: 0.0042 kWh/m³ general exhaust air system: 0.0007 kWh/m³ solvent exhaust air system: 0.0021 kWh/m³ acid exhaust air system: 0.0009 kWh/m³ alkaline exhaust air system: 0.0025 kWh/m³ nitrogen system: 0.2209 kWh/m³ compressed dry air system: 0.2250 kWh/m³ process cooling water system: 1.3535 kWh/m³ and ultra-pure water system: 9.5502 kWh/m³. These data can be used to assess the efficiency of different energy-saving schemes and as a good reference for factory authorities. The PCW system's status before and after implementing energy conservation is discussed.     

Cut order planning for apparel manufacturing

Cut order planning is the problem of planning the fabric cut for a set of apparel orders. A specified set of garments is ordered by the customer to be produced by a given date. Affiliated with this order is a set of garment sizes, and patterns for cutting each size. The fabric for cutting the order must be arranged on the cutting table in such a way as to minimize the cost of cutting the order. This plan must incorporate a partition of the pattern pieces to be arranged on top of the fabric layout. A mathematical model of the problem is developed and analyzed. On the basis of this analysis, solution approaches are developed that have been implemented on a desktop PC-based computer. Validated on representative industry problems, the approach is shown to be effective and versatile.     

Infant carrying by nulliparous female vervet monkeys (Cercopithecus aethiops).

We examined allomaternal behavior in vervet monkeys (Cercopithecus aethiops) in order to understand its developmental consequences. For 3 years before our study, all but 1 newborn infant had been removed. Thus, the animals had little experience with infants. During 2 summers and the intervening fall, we scored animals' proximity (