Sniffing and smelling: separate subsystems in the human olfactory cortex

The sensation and perception of smell (olfaction) are largely dependent on sniffing, which is an active stage of stimulus transport and therefore an integral component of mammalian olfaction. Electrophysiological data obtained from study of the hedgehog, rat, rabbit, dog and monkey indicate that sniffing (whether or not an odorant is present) induces an oscillation of activity in the olfactory bulb, driving the piriform cortex in the temporal lobe, in other words, the piriform is driven by the olfactory bulb at the frequency of sniffing. Here we use functional magnetic resonance imaging (fMRI) that is dependent on the level of oxygen in the blood to determine whether sniffing can induce activation in the piriform of humans, and whether this activation can be differentiated from activation induced by an odorant. We find that sniffing, whether odorant is present or absent, induces activation primarily in the piriform cortex of the temporal lobe and in the medial and posterior orbito-frontal gyri of the frontal lobe. The source of the sniff-induced activation is the somatosensory stimulation that is induced by air flow through the nostrils. In contrast, a smell, regardless of sniffing, induces activation mainly in the lateral and anterior orbito-frontal gyri of the frontal lobe. The dissociation between regions activated by olfactory exploration (sniffing) and regions activated by olfactory content (smell) shows a distinction in brain organization in terms of human olfaction.     

High speed tooling

Creating tooling for a new product can be a long and expensive process. The authors explore the use of rapid prototyping technology for producing metal tools     

Symmetry aspects of pretransformation behavior in metallic alloys

This paper deals with pretransformation behavior in both mineral and alloy systems. Theory that has previously been developed on the existence of local structural variants in incommensurate structures is reviewed and later applied to the study of local interactions in pretransformation phenomena. A review of the pretransformation behavior in both potassium feldspar and the mineral cordierite shows that the important feature in both cases is a very strong interaction between two orthogonal transverse acoustical waves to create a local shear structure. In the case of potassium feldspar this shear structure is the required product in the transformation, but in cordierite the first shear structure to appear in the pretransformation mechanism is not the correct one. Why this should be is explained in detail from a group theoretical analysis of the situation. Ultimately in cordierite this initial structure gives way to the correct structure with the appearance of twinning. The theory developed from the study of the mineralogical examples is then applied to the familiar cubic to tetragonal martensitic transformation in alloys such as In Tl with satisfactory results. Formerly with Schlumberger Cambridge Research, P.O. Box 153, Cambridge CB2 OHG This paper is based on a presentation made in the symposium “Pre-transformation Behavior Related to Displacive Transformations in Alloys≓ presented at the 1986 annual AIME meeting in New Orleans, March 2-6, 1986, under the auspices of the ASM-MSD Structures Committee.     

Interdependence of Phase Chemistry, Microstructure, and Oxygen Fugacity in Titanate Nuclear Waste Ceramics

Titanate ceramic waste forms were prepared using several combinations of calcination atmosphere (N₂, N₂-3.5% H₂, H₂) and metallic redox buffers (Ni, Fe, Ti, Al) to examine the dependence of microstructure and durability upon oxygen activity. It was found that the microstructures and phase assemblages were mostly insensitive to the fabrication method, although in detail systematic changes were recognized. The correlation of aqueous durability with oxygen fugacity was not straightforward, because of density variations in the hot-pressed ceramics. These fluctuations in density dominated the dissolution characteristics of the waste forms and sometimes obscured the more subtle changes associated with redox potential. It is concluded that although the best durability is achieved at lower fugacities (i.e., Ti metal buffer and H₂ calcination atmosphere), a satisfactory product can be produced using any of the preparative routes examined, provided the material is completely densified.     

Non-stationarity,heterogeneity, scale effects,and anisotropy investigations on natural rock joint roughness using the variogram method

Bulletin of Engineering Geology and the Environment - The variogram method is used to investigate the effect of non-stationarity, heterogeneity, scale-related parameters and anisotropy on roughness...     

Modeling and optimization of cold extrusion process by using response surface methodology and metaheuristic approaches

Obtaining the optimal extrusion process parameters by integration of optimization techniques was crucial and continuous engineering task in which it attempted to minimize the tool load. The tool load should be minimized as higher extrusion forces required greater capacity and energy. It may lead to increase the chance of part defects, die wear and die breakage. Besides, optimization may help to save the time and cost of producing the final product, in addition to produce better formability of work material and better quality of the finishing product. In this regard, this study aimed to determine the optimal extrusion process parameters. The minimization of punch load was the main concern, in such a way that the structurally sound product at minimum load can be achieved. Minimization of punch load during the extrusion process was first formulated as a nonlinear programming model using response surface methodology in this study. The established extrusion force model was then taken as the fitness function. Subsequently, the analytical approach and metaheuristic algorithms, specifically the particle swarm optimization, cuckoo search algorithm (CSA) and flower pollination algorithm, were applied to optimize the extrusion process parameters. Performance assessment demonstrated the promising results of all presented techniques in minimizing the tool loading. The CSA, however, gave more persistent optimization results, which was validated through statistical analysis.

     

Factors associated with male workers' engagement in physical activity: white collar vs. blue collar workers

The purpose of this study was to identify factors associated with male workers' participation in different kinds of physical activity, noting differences between white collar and blue collar workers. This study examined the variables, perceived health status, self efficacy, perceived barriers, age, education, income, and job category (Pender, 1987) for their association with physical activity. Self efficacy and perceived health status were the cognitive-perceptual factors that predicted physical activity. Job category (e.g., blue collar vs. white collar) was found to be a highly significant predictor of physical activity. Comparing physical job requirements with the individual worker capacity can suggest to the occupational health nurse physical fitness programs that are most appropriate for individual workers.     

On the Relationship between Two Fatigue-Life Models

The relationship between two fatigue life distributions, namely the Birnbaum-Saunders and the Inverse Gaussian, is further investigated. An intimate connection exists between the two models, viz, the Birnbaum-Saunders is a mixture of two probability distributions: 1) an Inverse Gaussian random variable, and 2) the reciprocal of an Inverse Gaussian random variable. Advantages and disadvantages of the two distributions are discussed. The arguments favour the Birnbaum-Saunders distribution from a stochastic modeling point of view, whereas the Inverse Gaussian distribution seems to be the more attractive of the two with respect to statistical analysis and analysis of censored data.     

Modeling Particle-Size Distribution Dynamics during Precipitative Softening

A population balance model was developed to simulate simultaneous precipitation and flocculation during precipitative softening. Rate coefficients for nucleation, crystal growth, and flocculation were extracted from experimental particle-size distribution (PSD) data based on changes in the total number and total volume of particles. Three models of flocculation were evaluated: rectilinear, curvilinear, and an empirical size-independent model. Model simulations were compared with experimental PSD data to test which model was most appropriate. The curvilinear precipitative flocculation model was superior when seeded precipitation occurred at moderate mixing intensities (G = 50–100?s?1). However, the curvilinear model overpredicts the formation of very large particles and requires values of the collision efficiency greater than 1.0, suggesting a more complicated dependence of the PSD dynamics on mixing intensity and saturation ratio than presently included in the model. At higher mixing intensities (G = 300?s?1), flocculation exhibited size-independent behavior, indicating that physical/chemical aspects of the precipitation process are altering or overshadowing the physics described in the curvilinear flocculation model.     

Effects on Escherichia coli inactivation and quality attributes in apple juice treated by combinations of pulsed light and thermosonication

Pulsed light (PL) and Thermosonication (TS) were applied alone or in combination using a continuous system to study their effect on Escherichia coli inactivation in apple juice. Selected quality attributes (pH, °Brix, colour (L, a, b, ΔE), non-enzymatic browning (NEBI) and antioxidant activity (TEAC)) were also evaluated pre- and post-processing. Two PL (360 μs, 3 Hz) treatments were selected and the juice exposed to energy dosages of 4.03 J/cm² (‘low’ (L)) and 5.1 J/cm² (‘high’ (H)) corresponding to 51.5 and 65.4 J/mL, respectively. The juice was also processed by TS (24 kHz, 100 μm) at 40 °C for 2.9 min (L) or 50 °C for 5 min (H), corresponding to 1456 and 2531 J/ml energy inputs, respectively. The effect of the resulting four energy levels and sequence (PL + TS and TS + PL) was studied. When the technologies were applied individually the maximum reduction achieved was 2.7 and 4.9 log CFU/mL (for TS (H) and PL (H) respectively), while most of the combined treatments achieved reductions in the vicinity of 6 log CFU/mL, showing an additive effect for both technologies when acting in combination, regardless of the sequence applied. All treatments significantly changed the colour of apple juice and the sequence in which the technologies were applied affected colour significantly (P < 0.05). The energy level applied did not affect any of the measured quality attributes.