Model-based predictive control of office window shades

In the automation of interior window shading devices, a control system that relies on a prediction of environmental conditions and a building's thermal response can provide savings to space-conditioning loads beyond what can be achieved using a reactive approach. The development of these control strategies can be difficult because of the uniqueness of each building. A simplified model-based predictive control (MPC) method for window shades is proposed. To this end, a control-oriented model representing the heat transfer problem in a perimeter office space was developed. The parameters of the model were estimated using the ensemble Kalman filter (EnKF). The energy-savings potential of the EnKF-based MPC approach for window shades was investigated using EnergyPlus simulations. This was accomplished by implementing the control-oriented model into the energy management system application of EnergyPlus. Simulations were conducted to assess the energy saving potential of using the EnKF-based MPC for roller blinds in a south-facing perimeter office space in Ottawa, Canada. The simulation-based results indicate the potential for about 35% reduction in electricity usage for space conditioning over manually operated interior roller blinds.     

Moderating effects of three coping strategies and self-esteem on perceived discrimination and depressive symptoms: A minority stress model for Asian international students.

This study examined 3 coping strategies (reflective, suppressive, and reactive), along with self-esteem, as moderators of the relation between perceived discrimination and depressive symptoms. International students (N = 354) from China, India, Korea, Taiwan, and Hong Kong provided data via an online survey. The role of perceived general stress was statistically controlled. Hierarchical regression analyses indicated a significant direct effect of perceived discrimination, a significant 2-way interaction of perceived discrimination and suppressive coping, and a significant 3-way interaction of perceived discrimination, reactive coping, and self-esteem in predicting depressive symptoms. An increased tendency to use suppressive coping appeared to strengthen the association between perceived discrimination and depressive symptoms. In contrast, the association between perceived discrimination and depressive symptoms was not significant when reactive coping was infrequently used, but only for students with relatively high self-esteem. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Approximated Fractional-Order Inverse Chebyshev Lowpass Filters

In this paper we use a least-squares fitting routine to approximate the stopband ripple characteristics of fractional-order inverse Chebyshev lowpass filters which have fractional-order zeros and poles. MATLAB simulations of \((1+\alpha )\)-order lowpass filters with fractional steps from \(\alpha =0.1\) to \(\alpha =0.9\) are given as examples. SPICE simulations of 1.2-, 1.5-, and 1.8-order lowpass filters and experimental results of a 1.5-order filter using approximated fractional-order capacitors in a Multiple-Input Biquad circuit validate the implementation of these circuits.     

Microfluidic purification and preconcentration of mRNA by flow-through polymeric monolith

Efficient and rapid isolation of mRNA is important in the field of genomics as well as in the clinical and pharmaceutical arena. We have developed UV-initiated methacrylate-based porous polymer monoliths (PPM) for microfluidic trapping and concentration of eukaryotic mRNA. PPM are cast-to-shape and are tunable for functionalization using a variety of amine-terminated molecules. Efficient isolation of eukaryotic mRNA from total RNA was first mathematically modeled and then achieved using PPM in capillaries. Purification protocols using oligo dT's, locked nucleic acid substituted dT's, and tetramethylammonium chloride salts were characterized. mRNA yield and purity were compared with mRNA isolated by commercial kits with statistically equivalent yields and purities (determined by qPCR ratio of 18s rRNA and Gusb mRNA markers). Even after extracting 16 microg of mRNA from 315 microg of total RNA, the 0.4-microL volume monolith showed no signs of saturation. Elution volumes were below 20 microL with concentrations up to 1 microg/microL. In addition, the polymeric material exhibited exceptional stability in a range of conditions (pH, temperature, dryness) and was stable for a period of months. All of these characteristics make porous polymer monoliths good candidates for potential microfluidic sample preconcentrators and purifiers.     

Two-wave-plate compensator method for full-field retardation measurements

The two-wave-plate compensator (TWC) method is expanded for full-field retardation measurements by use of a polarization microscope. The sample image is projected onto a CCD camera connected to a computer, allowing the retardation to be measured at all pixels. The retardation accuracy of this implementation of the TWC is evaluated to be 0.06 nm. The method is applied to polarization-maintaining fibers and long-period fiber gratings. The measured retardation is in good agreement with the crossed-polarizer images of the fibers. The method achieves a spatial resolution of 0.45 microm and a retardation resolution of 0.07 nm. The full-field TWC method can thus be a useful tool for characterizing and monitoring the fabrication of optical devices.     

Bulk acoustic resonator based on piezoelectric ZnO belts

In this paper, a bulk acoustic resonator based on ZnO belts is demonstrated. This device shows a great deal of promise in applications as an electronic filter and as a mass sensor. The fabricated device was characterized using vector network analysis, and both the first and third harmonics of resonance were observed at approximately 247 and 754 MHz, respectively. A one-dimensional Krimholt-Leedom-Matthaei model was utilized to predict the resonant frequency of the device and confirm the observed behavior.     

Increased remineralization of tooth enamel by milk containing added casein phosphopeptide-amorphous calcium phosphate

Casein phosphopeptide amorphous calcium phosphate nano-complexes (CPP-ACP) in chewing gum, lozenges and mouthrinses have been shown to re-mineralize enamel subsurface lesions in human in situ experiments. The aim of this double-blind, randomized clinical study was to investigate the capacity of CPP-ACP added to bovine milk to re-mineralize enamel subsurface lesions in situ. Ten subjects drank milk containing either 2.0 or 5.0 g CPP-ACP/l or a control milk whilst wearing removable appliances with enamel slabs containing subsurface demineralized lesions. Each 200 ml milk sample was consumed once a day for each weekday over three consecutive weeks. After each treatment and one weeks rest the subjects crossed over to the other treatments. At the completion of the treatments the enamel slabs were removed and remineralization determined using microradiography and microdensitometry. The results demonstrated that all three milk samples re-mineralized enamel subsurface lesions. However, the milk samples containing CPP-ACP produced significantly greater remineralization than the control milk. The re-mineralizing effect of CPP-ACP in milk was dose-dependent with 2.0 and 5.0 g CPP-ACP/l producing an increase in mineral content of 70 and 148%, respectively, relative to the control milk. The differences in remineralization following exposure to the three milk samples were all statistically significant (P<0.001). In conclusion, this study shows that the addition of 2.0-5.0 g CPP-ACP/l to milk substantially increases its ability to re-mineralize enamel subsurface lesions.     

Rollover crashes: predicting serious injury based on occupant, vehicle, and crash characteristics

The purpose of this research was to determine occupant, vehicle, and crash characteristics predicting serious injury during rollover crashes. We compared 27 case occupants with serious or greater severity injuries with 606 control occupants without injury or with only minor or moderate injury. Odds ratios (OR) for individual variables and logistic regression were used to identify predictive variables for serious injury associated with rollovers. Cases more often had thorax, spine, or head injury compared to controls that more often had extremity injuries. Intrusion (especially roof rail or B-pillar intrusion) at the occupant's position, the vehicle interior side and roof as sources of injury, and improper safety belt use were significantly associated with serious injury. Even when safety belt use or proper use was controlled for, occupants with greater magnitude of intrusion at their seat position were about 10 times more likely to receive serious injury. Although prevention of rollover crashes is the ultimate goal, it is important to develop safer vehicles and safety systems to better protect occupants who are involved in rollover crashes. This also requires improvement in data collection systems documenting these types of crashes.     

Re-electrospraying splash-landed proteins and nanoparticles

FITC-albumin, Lsr-F, or fluorescent polystyrene latex particles were electrosprayed from aqueous buffer and subjected to dispersion by differential electrical mobility at atmospheric pressure. A resulting narrow size cut of singly charged molecular ions or particles was passed through a condensation growth tube collector to create a flow stream of small water droplets, each carrying a single ion or particle. The droplets were splash landed (impacted) onto a solid or liquid temperature controlled surface. Small pools of droplets containing size-selected particles, FITC-albumin, or Lsr-F were recovered, re-electrosprayed, and, when analyzed a second time by differential electrical mobility, showed increased homogeneity. Transmission electron microscopy (TEM) analysis of the size-selected Lsr-F sample corroborated the mobility observation.