Co-registered Frequency-Domain Photoacoustic Radar and Ultrasound System for Subsurface Imaging in Turbid Media

Frequency-domain photoacoustic radar (FD-PAR) imaging of absorbers in turbid media and their comparison and/or validation as well as co-registration with their corresponding ultrasound (US) images are demonstrated in this paper. Also presented are the FD-PAR tomography and the effects of reducing the number of scan lines (or angles) on image quality, resolution, and contrast. The FD-PAR modality uses intensity-modulated (coded) continuous wave laser sources driven by frequency-swept (chirp) waveforms. The spatial cross-correlation function between the PA response and the reference signal used for laser source modulation produces the reconstructed image. Live animal testing is demonstrated, and images of comparable signal-to-noise ratio, contrast, and spatial resolution were obtained. Various image improvement techniques to further reduce absorber spread and artifacts in the images such as normalization, filtering, and amplification were also investigated. The co-registered image produced from the combined US and PA images provides more information than both images independently. The significance of this work lies in the fact that achieving PA imaging functionality on a commercial ultrasound instrument could accelerate its clinical acceptance and use. This work is aimed at functional PA imaging of small animals in vivo.     

Thermomechanical formation and recovery of nanoindents in a shape memory polymer studied using a heated tip

This paper investigates the thermomechanical formation and recovery of nanometer-scale indents in a shape memory polymer (SMP), studied using a heated atomic force microscope (AFM) tip and hot-stage atomic force microscopy. The material tested is a tert-butyl acrylate (tBA)-based polymer, which has a glass transition temperature of 60 degrees C. The AFM tip forms indents in the polymer in the temperature range 25-250 degrees C. The shape recovery of the indents is studied while the polymer is heated up to 100 degrees C. The temperature required for complete annealing of the indents depends upon the indentation formation conditions, with higher temperature formation corresponding to higher temperature recovery.     

Impacts of frequency and posture on body mass index in manual handling tasks

Workspace design plays an important role in ensuring workers' safety and welfare. The issue is more pressing in the manufacturing industry, where many workers must remain in a standing position, assume awkward postures, and perform repetitive tasks for extended periods of time. In this research, an electromyographic measurement technique was used to measure activity of four back muscles: the trapezius p. descendens, the deltoideus p. scapularis, the infraspinatus, and the latissimus dorsi. The results showed a statistically significant (p < 0.05) impact of left versus right side of the body, the degree of rotation to the right side of the body (0, 30, and 60 degrees rotation to the mid‐sagittal plane), body mass index level (normal weight [<25 kg/m²] vs. overweight [?25 kg/m²]), and tasks (high vs. low frequency). In this study, the role that workers and workspace variation play is clearly associated with an increase in the amplitude of electromyography at the targeted back muscles. © 2009 Wiley Periodicals, Inc.     

Managing lean DRC systems with demand uncertainty: an analytical approach

This paper considers a dual resource constrained manufacturing system with identical parallel work cells, which operates in an environment with demand uncertainty. The system is evaluated under the principles of lean manufacturing: zero lead times, zero inventories, and zero defects. The study shows that group-dispatching rules and labor assignment policies have a significant impact on manufacturing productivity. By properly managing the changeover-per-unit output ratios and operator assignments, the available capacity for value adding activities is increased and manufacturing cost is reduced. Results of an experiment show that labor requirements can be reduced from 5% to 46% and, machine utilization can be reduced from 2% to 14%.     

Slug flow characterization in horizontal annulus

To characterize slug flows in annuli channels and highlight the effect of the eccentricity on the flow behaviors, experiments were conducted in two horizontal annuli setups (a) concentric and (b) fully eccentric using air and water as the testing fluids. The range of air and water superficial velocities investigated were 0.45–3.49 m/s and 0.15–2.77 m/s, respectively. Slug parameters measured using conductance probes designed for this study include slug length, translational velocity, slug frequency, and slug holdup. It is found that the slug translational velocity is unaffected by the annulus eccentricity; however, parameters including slug frequency, slug holdup, and slug lengths have a higher value in the fully eccentric annulus when compared with the concentric one. We introduced a new definition of hydraulic diameter, which reconciles the correlation between the dimensionless mean slug length and the mixture velocity of the horizontal annuli with different setups.     

A review on long-term sorption solar energy storage

In the past decade, long-term sorption and thermochemical heat storage has generated lot of interest. This paper presents the state of the art in this field of research, materials used in these systems and technological difficulties that researchers are set against. An emphasis is put on recent demonstrative projects including absorption and adsorption for long-term solar energy storage. It emerges that considerable breakthrough have been made. Even though there is no mature long-term sorption or thermochemical energy storage yet, primarily due to the high cost of materials, the suitability of this technology to long-term storage remains its main power of attracting.     

Evaluation of a job‐aiding tool in inspection systems

Visual inspection plays a very important role in ensuring quality in the manufacturing and service industries. Two determinants of inspection performance are visual search and decision‐making. Improvement in any one of the components will have an impact on system performance. Job‐aids, accompanied by training, have proven to be effective in enhancing accuracy and reducing search time in visual inspection systems. This article aims to investigate the effects of search strategy along with task complexity and pacing on inspection performance using a job‐aiding tool. To facilitate the experiments, an enhanced job‐aiding tool in a simulated visual inspection environment was developed. This tool enables an inspector to track his or her search path in visual inspection systems. A pilot study and two experiments were conducted using this tool. The pilot study examined the effectiveness of the job‐aiding tool. The first experiment studied the effect of search strategy and task complexity on inspection system performance and the second experiment studied the impact of search strategy, task complexity, and pacing on system performance. Results from this research can be used to better design an inspection system. © 2007 Wiley Periodicals, Inc.     

Identification of thermotolerant Campylobacter species from poultry using an enzyme-labelled oligonucleotide DNA probe

A commercially available enzyme-labelled DNA probe for human Campylobacter strains has been tested and also found to hybridize with DNA from C. jejuni and C. coli isolates from poultry. DNA from 11 enteric, non-campylobacter organisms, included in the test as negative controls, failed to hybridize with the probe indicating that the probe might be used for identification of campylobacter from poultry too.     

Automation of solid-phase microextraction in high-throughput format and applications to drug analysis

The automation of solid-phase microextraction (SPME) coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS) was accomplished using a 96 multiwell plate format, a SPME multifiber device, two orbital shakers, and a three-arm robotic system. Extensive optimization of the proposed setup was performed including coating selection, optimization of the fiber coating procedure, confirmation of uniform agitation in all wells, and the selection of the optimal calibration method. The system allows the use of pre-equilibrium extraction times with no deterioration in method precision due to reproducible timing of extraction and desorption steps and reproducible positioning of all fibers within the wells. The applicability of the system for the extraction of several common drugs is demonstrated. The optimized multifiber SPME-LC-MS/MS was subsequently fully validated for the high-throughput analysis of diazepam, lorazepam, nordiazepam, and oxazepam in human whole blood. The proposed method allowed the automated sample preparation of 96 samples in 100 min, which represents the highest throughput of any SPME technique to date, while achieving excellent accuracy (87-113%), precision (相似文献   

The effect of lactic acid sprays on the keeping qualities of meat during storage

Spraying the meat surface of skinned cow heads with 1% v/v lactic acid resulted in significant reduction in total viable counts of bacteria at storage temperatures of 4, 15 and 20 degrees C. The number of coliform bacteria was also reduced at all three temperatures but the reductions were not statistically significant on most occasions. However, after five and two days at 15 degrees C and 20 degrees C, respectively, when the initial effect of acid appeared to be lost, the number of coliforms on sprayed heads exceeded those on unsprayed heads. The shelf lives of all sprayed heads were observed to have been extended for about three days at 4 degrees C and one day for both 15 degrees C and 20 degrees C.