The Norwegian Façade Insulation Study: the efficacy of façade insulation in reducing noise annoyance due to road traffic

The ergodic propriety of a room has strong effects on its reverberation. If the room is ergodic, the reverberation can be broken up in two steps: a deterministic process followed by a stochastic one. The late reverberation can be then modeled by a reverberation algorithm instead of more computationally consuming methods. In this study, the free path temporal distribution obtained by ray-tracing is used as an indicator of the room's mixing: the energetic average of the path lengths is computed at each time step. Ergodic rooms are thus characterized by rapidly convergent distributions. The free path value becomes independent of time. On the other hand, path selection mechanism and orbits are observed in non-ergodic rooms. The transition time from the deterministic process to the stochastic one is also studied through the evaluation of the room's time constant. It is shown that its value depends only on the mean free path and the boundaries scattering value. An empirical expression is obtained which agrees well with simulations carried out in a concert hall. This transition time from a deterministic model to a stochastic one can be used to speed up the acoustical predictions and auralizations in ergodic rooms.     

Determining the efficacy of a nanotechnology media product in enhancing children’s engagement with nanotechnology

Public engagement in nanotechnology media products can lead to a greater interest in understanding of nanotechnology. A study was undertaken to determine middle school student engagement in Nanooze, a magazine featuring nanotechnology research that has been developed for a young adult audience. Teachers at 116 Detroit middle schools distributed two issues of the magazine to their students, and surveys were collected from 870 students after reading the magazines. Results suggest that the majority of students liked reading the magazine and learned something about nanotechnology. Engagement in nanotechnology led to understanding of nanotechnology. The Nanooze magazine was an effective medium for engaging middle school students in learning about nanotechnology.     

Advances in optoelectronics in europe—the RACE and ESPRIT programmes

EditorialSpecial issue

Advances in optoelectronics in europe—the RACE and ESPRIT programmes     

Effects of traffic noise on pupils''''behavior in classroom

Noise surveys in this country reported that a large number ofclassrooms in primary and secondary schools in the urban areas were dis-turbed by environmental noise,particulariy by traffic noise.A series ofpsychological tests were conducted to identify pupils'behavior in aclassroom under different noise levels within the range of 40 to 70 dBA.Statistical analysis results were obtained by using Relational Data Analy-sis System(RDAS)software.According to the t-test and single factor vari-ance analysis of the results,significant differences of the pupils'behaviorin the classroom have been observed when the percentile exceeded soundlevel either L_(50) exceeds 50 dBA or L_(10) exceeds 55 dBA,or the equivalentcontinuous sound level L_(eq) exceeds 50 dBA.The same conclusion hasbeen drawn from the average percentages of syllable articulation under different noise levels in a classroom which were the results of tests made inacdordance with the procedure described in the National Standard.Themaximum acceptable noise     

Angular dependence of shot noise in the presence of Rashba spin–orbit coupling in semiconductor spintronics junctions

We investigate spin-dependent current and shot noise, taking into account the Rashba spin–orbit coupling (RSOC) effect in double diluted magnetic semiconductor (DMS) barrier resonant tunneling diodes. The calculation is based on an effective mass approach. The magnetization of DMS is calculated by the mean-field approximation in low magnetic field. The spin-splitting of DMS depends on the sp–d exchange interaction. We also examine the dependence of transport properties of CdTe/CdMnTe heterostructures on applied voltage and relative angle between the magnetization of two DMS layers. It is found that the RSOC has great different influence on the transport properties of tunneling electrons with spin-up and spin-down, which have different contributions to the current and the shot noise. Also, we can see that the RSOC enhances the spin polarization of the system, which makes the nanostructure a good candidate for new spin filter devices. Thus, these numerical results may shed light on the next applications of quantum multilayer systems and make them a good choice for future spintronics devices.     

Measurement and simulation of partial discharge in oil-paper insulation under the combined AC–DC voltage

Depending on unique operation characteristics for voltage applied on valve side winding of the converter transformers, it is extraordinarily significant to study the partial discharge (PD) behavior with oil-paper insulation under combined AC–DC voltage. Therefore, this paper investigated PD inception characteristics by pulse current methods with needle-plate electrode system under combined AC–DC voltage. Furthermore, 3D electric field distributions versus combined AC–DC voltage in different ratios were calculated by Finite Element Analysis (FEA). An experimental conclusion was drew that AC partial discharge inception voltage (PDIV) in pure oil would decrease linearly with the DC component increasing but the inception voltage with oil-paper insulation appeared to be independent of DC voltage and dependent of AC voltage. And 3D electric field distribution deduced from simulation provided a supplementary proof on the experimental results. Moreover, high speed photography was used to capture emitted light produced by discharge, estimate streamer velocity (1.8 km/s) and record streamer initiation and propagation process in oil gap. Previous studies have shown that the prebreakdown phenomena involving the generation and propagation of vapor channels through the oil could be divided into a three-stage process.     

Experimental studies on the impact of ASE noise of single-channel optical amplifiers in central office applications

We identified the amplified spontaneous emission-amplified spontaneous emission (ASE-ASE) beat noise from the semiconductor optical amplifier, which has been overlooked in previous studies, as a cause of severe system penalties when it was used to provide single-channel amplification in a dynamic central office environment through experimental studies. Our results pointed out that the ASE-ASE beat noise of the optical amplifier, other than its gain and noise figure, has to be considered to correctly predict its performance in these new applications.     

Effect of external noise on the dynamical localization of two coupling electrons in quantum dot array

The effect of external noise, which is characterized by an Ornstein--Uhlenbeck process, on the dynamical localization of two coupling electrons in a quantum dot array under the action of an ac electric field is studied. A numerical solution of the stochastic equations is obtained by averaging over stochastic trajectories. The results show that the external noise may destroy the dynamical localization, but the anti-noise capacity of the system is stronger when the two electrons are localized at the ends of the quantum dot array.     

Security analysis of the “Ping–Pong” quantum communication protocol in the presence of collective-rotation noise

Environmental noise is inevitable in non-isolated systems. It is, therefore, necessary to analyze the security of the “Ping–Pong” protocol in a noisy environment. An excellent model for collective-rotation noise is introduced, and information theoretical methods are applied to analyze the security of this protocol. If noise level ε   is lower than 11%, an eavesdropper can gain some, but not all, information freely without being detected. Otherwise, the protocol becomes insecure. We conclude that the use of ‘Ping–Pong’ protocol as a quantum secure direct communication (QSDC) protocol is quasi-secure, as declared by the original author when ε?11%$\epsilon ?11\text{\%}$.     

Stress perception of Chinese disyllabic words in utterance

A perceptual experiment was conducted on the stress of 1,898 Chinese disyllabic words in 300 sentences taken from the Chinese speech corpus of Microsoft Research Asia. The analyses revealed (1) that the perceptual stress location in utterance was influenced by the prosodic boundary where a word stood; (2) that -the perceptual stress degree of a syllable was positively correlated with the pitch of the syllable and the duration as well, while the correlation coefficient between the stress degree and the pitch was larger than that between the stress degree and the duration; (3) that the pitch and the duration was not correlated if there was no pause following a word, but weakly and positively correlated if there was a pause; (4) that tone pattern of a syllable showed an effect on stress perception. The results of the experiment indicate that the perceptual characteristics of word stress in utterance are quite different from those in isolated words.     

A snapshot of young adults’ noise exposure reveals evidence of ‘Binge Listening’

There have been several previous studies into daily noise exposure levels in modern urban communities, which typically report mean noise exposure levels (L_Aeq) for adults between 73 and 79 dB. In this study, rather than focus on group mean exposures across a wide age range, individual patterns of noise exposure over 4- and 5-day periods were examined in a group of 45 young adults aged 18–35 years. The main objective of the study was to determine the extent to which young adults exhibit a ‘binge listening’ pattern of noise exposure, i.e., high weekend leisure noise vs. low weekday work noise exposure. A secondary objective was to identify the types of activities that generate the highest noise exposures. The results showed that although most participants (60%) were exposed to low daily noise levels, 33% of participants exhibited a ‘binge listening’ exposure pattern characterized by one or two high-noise days, usually a Friday, Saturday or Sunday, preceded or followed by much quieter days. The most notable high-noise activities were playing an instrument solo or in a band; attending a nightclub; and attending a pop concert, each of which recorded average noise levels greater than 100 dB. Future research is needed to determine whether ‘binge listening’ is more or less harmful than the chronic exposure presupposed in traditional risk models, however, under the equal-energy principle, repeated ‘binge’ noise exposures from weekend visits to nightclubs, live music events and other high-noise events represent a significant risk to long-term hearing health.     

Can mobile defects be the source of 1/f noise in a semiconductor?

We discuss two alternative approaches relating the occurrence of 1/f noise in semiconductors with fluctuations in the mobility of current carriers. In the first approach, 1/f noise is associated with fluctuations in scattering of the carriers by the acoustic phonons of the lattice. According to the second approach, the source of 1/f noise is fluctuations in the scattering cross section of mobile defects. Experimental data in favor of the first approach are analyzed. It is shown that, to explain the data in terms of the model of fluctuations in the scattering cross section of mobile defects, a new effect must exist. Namely, manufacturing a semiconductor with an increased degree of doping must result in a proportional decrease in the density of mobile defects that are responsible for the generation of 1/f noise. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 6, pp. 590–594, June 1999.     

A study on approaching motion perception in periphery with binocular viewing: Visibility is increased in the absence of one eye’s information

The visibility of an approaching target on the horizontal plane in peripheral vision with binocular viewing was studied. It was found that the perceptual performance for the target moving toward the middle point of the two eyes was remarkably worse; under this circumstance it has rather high performance in the absence of one eye’s target information with occlusion or falling on the blind spot. These facts imply that the conventional change disparity mechanism does not work in the peripheral visual field; while some simple combinations of the monocular information of two eyes, such as the sum of two eyes’ image motion with sign, can be used to detect an approaching motion in the periphery.     

Triangle Geometry of the Qubit State in the Probability Representation Expressed in Terms of the Triada of Malevich’s Squares

We map the density matrix of the qubit (spin-1/2) state associated with the Bloch sphere and given in the tomographic probability representation onto vertices of a triangle determining Triada of Malevich’s squares. The three triangle vertices are located on three sides of another equilateral triangle with the sides equal to\( \sqrt{2} \). We demonstrate that the triangle vertices are in one-to-one correspondence with the points inside the Bloch sphere and show that the uncertainty relation for the three probabilities of spin projections +1/2 onto three orthogonal directions has the bound determined by the triangle area introduced. This bound is related to the sum of three Malevich’s square areas where the squares have sides coinciding with the sides of the triangle. We express any evolution of the qubit state as the motion of the three vertices of the triangle introduced and interpret the gates of qubit states as the semigroup symmetry of the Triada of Malevich’s squares. In view of the dynamical semigroup of the qubit-state evolution, we constructed nonlinear representation of the group U(2).     

Statistical energy analysis of rotating cylindrical shell ’s cutting noise

It is difficult to study the contribution to total cutting noise of eachsound radiator in cutting system by means of traditional theoretical or experi-mental methods.In this paper,problems associated with cylindrical thinshell‘s cutting noise are studied by applying Statistical Energy Analysis ofNon-Conservatively Coupled Systems under Correlative Power Input.Theoryand techniques for parameter evaluation,cutting system modelling and otherimportant problems concerned are also discussed.Results show that cuttingnoise is mainly from the sound radiation of workpiece in cutting process,andStatistical Energy Analysis can be applied successfully to the research of largecylindrical shell‘s cutting noise.     

Nuclei in the vicinity of ‘island of inversion’ through the fusion reaction

The level structures of N ～ 19 nuclei such as ^32,34P have been investigated using the ¹⁸O(¹⁸O,xnyp) and ¹⁸O(¹⁶O,xnyp) reactions at an incident beam energy of about 34 MeV. The de-exciting γ-transitions were recorded using an array of clover detectors. These detectors have the dual advantage of higher efficiency at E _γ ≥ 2 MeV, and are capable of providing information on the linear polarization of the observed γ-transitions. These polarization measurements when coupled with the angular correlations help us to assign uniquely the spin parity for the observed levels. The experimental results have been compared with the predictions of the spherical shell model. The shell-model calculations are able to reproduce the observed energy levels to a reasonable degree. However, the observed transition probabilities are not reproduced by the calculations. Hence there is a need to re-visit these calculations using more detailed and microscopic effective interactions.     

Anisotropy of the Resonance Transformation of the Microhardness of Crystals after Their Exposure in the EPR Scheme in the Earth’s Magnetic Field

It is shown that the preliminary exposure of ZnO, triglycine sulfate, and potassium hydrogen phthalate crystals in ultralow crossed magnetic fields—Earth’s magnetic field and ac pump field—leads to a resonance change in their microhardness. The resonance frequency of microhardness peaks is determined by the classical condition of electron paramagnetic resonance only at certain orientations of the crystals with respect to the Earth’s magnetic field B_Earth. Rotations of all samples with respect to the direction B_Earth by angle θ reduce the resonance frequency in proportion to cosθ. The observed anisotropy has been attributed to the presence of their own local magnetic fields B_loc ? B_Earth in the crystals.     

Influence of ocular dominance in the variability of the eye’s anterior segment measurements

The visual system tends to favour one eye over the other in perceptual or motor tasks. This effect, called ocular dominance, makes those small movements in one eye be smaller and more precise than in the other eye. These dynamic effects are usually small and static devices are not capable of detecting differences between both eyes. In the last years ophthalmic devices are becoming more and more precise, thus they can be sensible to such variability. The hypothesis posed here is that variability of measures acquired this way is affected by ocular dominance. With a Pentacam system we have measured several parameters of the anterior segment of the eye. Our findings show that variables measured for the dominant eye are less dispersive than for the non-dominant eye although the limited accuracy of the device can mask this effect. The trend is confirmed by a contrast experiment and by a previous work, so we accept the validity of our hypothesis. Our main conclusion is that systematic election of the right eye in analysis of reliability or reproducibility can bias the variability of results and consequently we suggest considering dominance effects.