Non-laboratory Environment Research Articles

Fibre optic sensors for the characterization of particle size and flow velocity

Photon correlation spectroscopy (PCS) has been applied to the routine monitoring of proteins eluting off liquid chromatographic separation systems. The technique has been configured as an on-line, in situ detector capable of remote analyses using fibre optic technology. Analysis of flowing protein samples has been demonstrated and its use in process biochemistry as a quality assurance monitor is discussed. The bulk optics, gas lasers and sophisticated detection systems found in conventional systems have been replaced with miniaturized solid-state components for incorporation into a fibre optic multiplexable (LANS) network for multipoint analyses at remote points in the non-laboratory environment. A fibre optic PCS system has been shown to analyse protein samples with close to theoretical maximum efficiency, permitting significant reductions in incident light powers to be achieved. The determination of flow velocity in more than one dimension is conventionally carried out using complex and expensive bulk optical systems. A fibre optic version, employing a single fibre pair, has been designed that will permit characterization of flow velocity profiles, independent of direction, for use as a multiplexable network capable of measurements in situations previously inaccessible to such analyses. The passive sensor head requires no alignment or adjustment and contains specially coated lenses on an individual fibre for generation of the required optical scattering volume.

A longitudinal study of the actor-observer attributional effect

This study examined the operation of the Jones-Nisbett actor-observer effect—i.e. the tendency for persons to see their actions as due to situational causes while observers of the same actions ascribe them to the actor's personal dispositions—in the natural, non-laboratory environment of everyday interactions over an extended period of time. Subjects were asked to provide trait descriptions of themselves and a close acquiantance over a 3 1 2 week period by choosing five adjectives each, for the self and the other person, from a large list comprised of 200 words which had been rated high on meaningfulness from Anderson's ( Journal of Personality and Social Psychology, 9, 272–279, 1968) list of 555 words scaled for likeableness, on 4 days each week. We assumed that the use of a relatively homogeneous set of trait-adjectives would reflect a more dispositional,trait-like, attribution since it describes the person as relatively consistent over time and, presumably, situations. Conversely, the use of a more heterogeneous set of adjectives would represent attributions to the diversity of situations that the person would likely find himself or herself in over the duration of the study. We thus expected the actor-observer effect to manifest itself in greater trait variability in descriptions of the self than of an acquaintance. Neither a measure of evaluative consistency nor of descriptive consistency yielded greater variability in self-descriptions than in other-descriptions. Because individual differences in a tendency toward the actor-observer attributional effect was a salient feature of our findings, we explored a possible personality correlate of this tendency—self-esteem—and found that those who conformed more to the effect were lower in self-esteem than those conforming to it less. Also, on the measure of descriptive consistency, we found variability in descriptions of the self and of the other person to be positively correlated. The implications of our findings regarding the limiting conditions of the Jones-Nisbett effect were discussed.

Reinforcing effects of nicotine in humans and experimental animals responding under intermittent schedules of i.v. drug injection.

The self-administration paradigm is an experimental model of drug dependence in which the reinforcing properties of drugs can be directly assessed. This paradigm avoids the possible confounding influence of nonpharmacologic factors which may contribute to drug taking in the nonlaboratory environment. When animals serve as subjects, social and cultural factors unique to humans may also be eliminated as confounding influences. Most drugs of abuse are self-administered by animals and humans under such conditions. Until 1981, laboratory studies of nicotine self-administration suggested that nicotine, in its own right, was only a marginally effective reinforcer. As will be shown in the present review, a study by Goldberg and his co-workers in 1981 [13] demonstrated clearly that nicotine could serve as a highly efficacious reinforcer in laboratory animals. There are several parameters which can function to substantially strengthen the behavior which leads to nicotine ingestion. These include the following: (1) intermittent availability of nicotine, (2) intermittent presentation of nicotine-paired stimuli, and (3) concurrent schedules of food reinforcement. Initial findings from a human IV nicotine self-administration study were consistent with those from the animal studies. Together these results confirm that nicotine can function to control behavior by serving as a reinforcer for animals and humans. The results also suggest that commonly used tobacco products function as ideal nicotine delivery systems for controlling behavior since they provide discrete nicotine-paired stimuli and lend themselves to intermittent nicotine delivery.

Smoking topography and nicotine blood levels

Frequency and durational components of smoking topography were measured by a portable smoking device while 10 subjects smoked four cigarettes ad libitum in a non-laboratory environment. Nicotine blood levels were measured before and after smoking each cigarette and serial blood samples for determining nicotine metabolic half-life were obtained the following day. Results showed that change in pre- and post-cigarette nicotine levels and metabolic half-life for nicotine were not related to within-cigarette topography measures or nicotine yield of cigarette, but were significantly related to intercigarette interval.

Smoking topography in a nonlaboratory environment.

The relationships between the number of cigarettes smoked/day and the number of puffs/cigarette, puff duration, and total puff time/cigarette were studied. Data were collected on 12 regular smokers for all cigarettes smoked over a 3-day period in a nonlaboratory environment. Between-subject variability was substantial on each of the topographical measures. Neither the number of cigarettes smoked per day nor the classification of Heavy (greater than 25 cigarettes/day) vs Moderate (less than 25 cigarettes/day) smoking levels was related to the intensity with which cigarettes were smoked. Within-subject consistency on the topography measures indicates that smokers may have relatively unique smoking patterns.

Looking where you listen: visual cues and auditory attention

In the non-laboratory environment, we are generally able to see the source of the sounds to which we are attending. In a preliminary examination of how and to what degree we might use this visual information, subjects shadowed one of two female voices when able to see the persons speaking (Experiment I) or when able to see, and thus precisely localize, the auditory loudspeakers (Experiment II). Selective performance was improved by being able to see the lip movements of the people whose voices were heard, and by being able to localize visually the sources of the voices.

A frequency-stabilised CW waveguide carbon dioxide laser

The operation and performance characteristics of a frequency stabilised carbon dioxide waveguide laser which has been designed to provide a compact, rugged and stable source of infrared radiation suitable for the non-laboratory environment is described. The laser produces a maximum output power of 4.75 W in the EH11 waveguide mode and is actively stabilised on the P(20) rotational-vibrational transition by means of an extra-cavity frequency reference provided by a Stark-effect-tunable resonance absorption in singly deuterated ammonia. Short-term (1 ms) stability of the output is about 5 kHz, and in the long term, the laser can be held to within 1 MHz for periods of many hours at a frequency which itself is voltage controllable over a range of about 200 MHz.

Some Response Characteristics of Parabolic Hot Films in Water

TURBULENCE in liquids presents an important problem for many disciplines from chemical engineering to ocean physics, hydraulic engineering, and fluvial geomorphology. In such areas mean velocities are usually low (less than 5 msec) and spectra of turbulence range over frequencies from about 300 Hz down to a scale determined by that of the experiment. The only instrument presently capable of measuring such a range in a nonlaboratory environment is the hot-film anemometer. The classic field experiment of Grant, Stewart, and Moilliet used a conical hot film probe to test Kolmogorov's hypotheses, while more recent field measurements in hydraulics have been carried out by Holley. The response of such an instrument is a subject of considerable concern, for no adequate theoretical model has been developed for its heat transfer characteristics. The frequency response of hot wires has been extensively studied since King's pioneering work (Davies and Fisher, Champagne et al., and Sandborn. Early work on hot films by Grant et al. and Evans tested the frequency response of conical hot films and found the response flat up to 200 Hz, then showing a tendency to rise with increasing frequency up to 1 kHz. However, the work of Fabula showed the response to drop for glass cylinders, the drop being greater for the 5 mil than 2-mil-diam sensor. No other work appears to have been carried out at frequencies above 1QO Hz. Hot films have come under increasing scrutiny since the commencement of commercial manufacture of the probes. Liu examined the response of a cylindrical hot film over the range 2-38 Hz and concluded that the response was essentially flat. More recent work of a similar nature was carried out by Rodriguez et al.,' in which probes of several different configurations were vibrated over a frequency range of 5-100 Hz in turbulent pipe flow, with a velocity range of 2-5 msec in viscoelastic solutions. Responses were practically flat over the entire range but showed a tendency to rise at frequencies below 10 Hz which, it was claimed, was due to experimental error. Theoretical studies of the dynamic characteristics of hot films have been carried out by Rasmussen and Bell-

Developmental solid-state imaging system

A developmental imaging system has been constructed as part of a long-term program to develop a high quality, high performance, all solid-state television for NASA. The purpose of the developmental system is to provide a test and demonstration vehicle for solid-state mosaics developed on the program and to obtain limited operational information in a nonlaboratory environment. The system, loosely packaged in an 8½-by-8½-by-10 inch volume including display sweep generator circuits, utilizes commercially available integrated circuit logic cards, discrete FET sampling switches, and a 100-by-128 element mosaic developed on the program. The camera provides a dynamic range of approximately five to seven shades of gray and operates on 6 volts at variable frame rates between 6 and 60 frames per second at light levels of 0.1 to 1 foot-candle, respectively. As of March, 1968, the system had been in operation for approximately one year without failure. This imaging system exhibits frame integration sensitivity due to storage of light-generated charge carriers in each phototransistor's collector-base depletion layer during the periods between its readout sampling. Fabrication of the sensor matrix and mechanization of the interrogation system for image readout from the mosaic are described. Considerations affecting imaging resolution, spectral response, responsivity dynamic range, and quantum efficiency are discussed.

Microwave-bandwidth optical receiver systems

A theoretical and experimental evaluation of optical communications systems capable of microwave bandwidths is presented. The optical transmitter, modulator, and detection techniques are discussed with respect to both direct-detection and optical heterodyne receivers, and experiments in a nonlaboratory environment are described. At the high optical power levels or photon rates which are fundamentally necessary for gigahertz instantaneous bandwidths, it is found that signal-shot-noise limited operation may be obtained with new wideband photodetectors incorporating internal gain. Direct-detection receivers are thus generally superior to heterodyne receivers in these systems. A comparison is made of the relative merits of alternative systems and their dependence on various parameters such as information capacity, range, and background illumination.