Olfactory sensitivity to group-specific substances in Atlantic salmon (Salmo salar L.)

The olfactory sensitivity of three groups of Atlantic salmon (Salmo salar L.) toward substances emanating from their own groups was studied. Thresholds were determined by electrophysiological recordings of the induced waves from the medial and lateral part of the olfactory bulb surface. The intestine contained more potent olfactory substances on a gram per liter basis than skin mucus, urine, or amino acids. Chemical fractions were obtained from a parallel study on the nature of the naturally occurring substances by Stabell et al. (1982). A retarded fraction from chromatography on a Sephadex G-25 column contained the most potent material. The most potent fractions of the intestinal content evoked responses mainly in the medial part of the olfactory bulb, whereas the lateral part responded to amino acids. The results suggest that all salmon smolts of the waterways contribute to an odor trail in the coastal currents, thus facilitating the odor-dependent migration of the mature salmon.     

Species-specific,two-component,volatile signals in two sympatric ant-lion species:Synclysis baetica andAcanthaclisis occitanica (Neuroptera,Myrmeleontidae)

The thoracic glands of males in two ant-lion speciesSynclysis baetica andAcanthaclisis occitanica, which occur sympatrically in Israel, were found to contain a volatile secretion with two-component blends of nerol oxide and (R,Z)-6-tridecen-2-ol (approx 15) and nerol oxide and 10-homonerol oxide (approx. 12), respectively. Chemical analyses were performed using gas chromatography-mass spectrometry, chiral gas chromatography, and ozonolysis, and the proposed structures were confirmed by synthesis. The species-specific, few-component volatile signals are thought to function as a reproductive isolation mechanism between the two sympatric species. Biochemical relationships between the nerol derivatives and between the unsaturated secondary alcohols are discussed.     

Energy performance contracting (EPC): a suitable mechanism for achieving energy savings in housing cooperatives? Results from a Norwegian pilot project

The barriers to energy savings in institutions and private homes are well known and include people’s lack of interest, awareness, knowledge and human and financial capacity. Experiences made in several countries show that EPC—energy performance contracting—may be used for overcoming many of these barriers. A typical EPC project is delivered by an energy service company (ESCO) and the contract is accompanied with a guarantee for energy savings. EPC is increasingly taken in use in the professional market (firms and the public sector), but is less common in the residential sector market. It has been suggested that there are several barriers for using EPC in the domestic sector such as the uncertainty involved in estimating forthcoming reductions in private consumption. In this paper, we present the results from a pilot project on the use of EPC in a housing cooperative in Oslo. The project was initiated and observed by the researchers. The research followed a transdisciplinary methodology in that it was conducted by both researcher and practitioner (co-authors) in close collaboration with members of the housing cooperative and the ESCOs, who also contributed to the interpretation of results. We document the process in terms of why the Board decided to join the EPC pilot, the call for offers from ESCOs who guaranteed that purchased annual energy would be reduced by one third, the responses to and negotiations of the offer from the ESCO who became contracted in the initial phase and up to the moment when the General Assembly finally decided to not invest in the proposed energy saving measures. We find that the residents not only had limited interest in energy savings but also lacked confidence in the EPC process. This contributed to the outcome. We discuss the findings in relation to the barriers to using EPC among housing cooperatives. We highlight the need for more knowledge about the client side for understanding how barriers may be overcome. Three specific recommendations for how EPC may successfully be employed among housing cooperatives are suggested as follows: (i) include refurbishment and not only energy savings in the EPC, (ii) identify the residents’ needs in an early phase and (iii) communicate the EPC principle to the residents throughout the process.     

On process parameter estimation for the tube hydroforming process

Tube hydroforming is a forming process where an inner pressure combined with axial feeding deforms the tube to the shape of a die cavity. One of the main concerns when designing such a process is to avoid burst pressure, i.e. the process state where the hardening of the material is unable to resist the increase in inner pressure and wall thickness reduction. The success of a hydroforming process strongly depends on the choice of process parameters, i.e. the combination of material feeding and inner pressure. Especially in hydroforming processes, where the free forming phase is substantial, the process is proved to be very sensitive to the inner pressure. By transforming the problem into a deformation controlled rather than a force controlled process, the results from the process parameter estimation become more reliable but on the other hand less intuitive. In this context, three distinct parameter estimation procedures are suggested. Firstly, a self feeding based procedure is proposed with the intention of being a fast method to be used as a first estimate of suitable process parameters. Secondly, an iterative optimization problem set up is presented. Thirdly, and finally, an adaptive simulation procedure based on process response approximations is proposed, which only requires a limited number of simulation runs.     

Effects of smoking bans on passive smoking exposure at work and at home. The European Community respiratory health survey

This longitudinal study investigated whether smoking bans influence passive smoking at work and/or at home in the same subjects. Passive smoking at work and/or at home was investigated in random population samples (European Community Respiratory Health Survey) in 1990‐1995, with follow‐up interviews in 1998‐2003 and 2010‐2014. National smoking bans were classified as partial (restricted to public workplaces) or global (extended to private workplaces). Multivariable analysis was accomplished by three‐level logistic regression models, where level‐1, level‐2, and level‐3 units were, respectively, questionnaire responses, subjects, and centers. Passive smoking at work was reported by 31.9% in 1990‐1995, 17.5% in 1998‐2003, and 2.5% in 2010‐2014. Concurrently, passive smoking at home decreased from 28.9% to 18.2% and 8.8%. When controlling for sex, age, education, smoking status, and ECHRS wave, the odds of passive smoking at work was markedly reduced after global smoking bans (OR = 0.45, 95% CI 0.25‐0.81), particularly among non‐smokers, while the protective effect of global smoking bans on passive smoking at home was only detected in non‐smokers. Smoking bans both in public and private workplaces were effective in reducing passive smoking at work in Europe. However, given the inefficacy of smoking bans in current smokers’ dwellings, better strategies are needed to avoid smoking indoors.     

Nano metrology of cylinder bore wear

Cylinder bores are multi-process surfaces whose roughness is difficult to characterise for tribological purposes by conventional methods. Statistical approaches may be used to compute asperity densities, summit curvatures and so on, but suffer from the usual disadvantage of tending to infinite values in the absence of a short-wavelength cutoff. A useful advance in tribological roughness assessment would be to find a means of establishing an appropriate scale of measurement. Using a form of the plasticity index corrected for anisotropy, a short-wavelength limit λ_p is derived below which asperities will not take part in long-term tribological interactions. A general relationship is obtained between three dimensionless numbers, the short-wavelength limit λ_p normalised by the topothesy Λ, the fractal dimension D and the material ratio (the ratio of the Hertzian elastic modulus E′ to the hardness H). From this relationship, presented as a carpet plot, the appropriate scale of roughness measurement for any tribological investigation of a fractal surface may be determined. With a stylus instrument and an atomic force microscope, a number of cylinder bores were measured at locations of both high and medium wear before and after running in. By inspection of an ensemble of structure functions, it is shown that cylinder bore surfaces are multifractal, with a transition point (the so-called “corner frequency”) at about 20 μn, corresponding to the average size of a honing grit. Below this length the surfaces are self-similar fractals down to the limits of AFM resolution. The short wavelength limit using the above formulation appears to be about 40 nm, weI1 below the range of instruments usually employed to measure tribological surface roughness.     

Mechanical properties of lightweight aggregates

Lightweight aggregates (LWAs) were successfully produced both in a pilot-scale rotary kiln and in a laboratory chamber furnace. The mechanical properties of LWA were investigated in detail applying the European standard crushing resistance test (CR-test) as well as the single pellet compression test (spc-test). The spc-test showed that LWA pellets with porosities <82% behave similar to solid brittle spheres under compression when considering only the solid fraction of the pellet and the strength may be calculated according to σ_crit = F_crit/d² where σ_crit is a porosity independent strength, F_crit is the measured load at failure and d the solid diameter (assuming zero porosity). It was reasoned that catastrophic failure was due to tensile stresses in the centre of the pellet and the strength was observed to increase exponentially with decreasing sample size. The relationship between the CR- and spc-test has been established facilitating “translation” of strength data between the two different test methods.     

Combating the effect of chassis squat in vehicle performance calculations by accelerometer measurements

The performance of a vehicle is measured as the time to complete an assigned task while accelerating. Non-intrusive performance measurements are often based on inertial navigation, i.e. measurements from an accelerometer are integrated once to obtain an estimate of the speed of the vehicle. A second integration results in a measure of the traveled distance. However, the suspension system of the vehicle introduces error in the measurements, owing to the tendency of the chassis to rise in the front and drop in the back during acceleration. An approach is derived based on the method of weighted least-squares for estimating the misalignment angle as a function of the horizontal acceleration. The proposed method includes a parametric model describing the effect of the tilt of the vehicle on the accelerometer measurements. Further, the method employs an external reference. It is shown that for a particular parametric model, the problem at hand has a closed-form solution. Certain practical applications are studied in some detail. A relative error of 0.5% in the elapsed time and 5% in the final speed is illustrated on 201-m straight track races.