Method for evaluation of the acoustical impedance of a black box, with or without mean flow, measuring pressures at fixed positions

The transmission-line or the impedance-tube method for the measurement of the acoustic impedance of any termination involves a search for various minima and maxima of pressure. For this purpose, arrangement has to be made for the microphone to travel along the length of the impedance tube, and this complicates the design of the tube considerably. The present paper discusses a method which consists in evaluating the tube attenuation factor at any convenient frequency by making use of measured SPL's at two (or more) fixed locations with a rigid termination, calculating the tube attenuation factor and wave number at the required frequency of interest with or without mean flow (as applicable), and finally evaluating the impedance of the given termination by measuring and using SPL's at three (or more) fixed locations. Thus, the required impedance tube is considerably smaller in length, simpler in design, easier to manufacture, cheaper in cost and more convenient to use. The design of the tube is also discussed. Incidentally, it is also possible to evaluate the impedance at any low frequency without having to use a larger impedance tube.

Earth pressures on retaining walls due to Anisotropic and nonhomogeneous backfills

In this paper an attempt is made to study the lateral earth pressures on retaining walls as affected by anisotropy and non-homogeneity with respect to cohesion, of the backfill. Both the passive and active conditions are studied and the method of characteristics is used in the analysis. Numerical results show that, as the coeficient of anisotropy, k, defined as the ratio of vertical strength to horizontal strength, changes from 0-8 to 2, the pressure at the top of the wall decreases considerably.Also, as k changes fvom 0.8 to 2, the mod$ed passive and active earth pressure coeficients decrease when cohesion increases with depth and are unaffected by k when cohesion is constant with depth. On the other hand, when the rate of increase of cohesion with depth increares, the mod@ed earth pressure coefficients are found to increase considerably.

Law student lifestyle pressures

One significant factor influencing student wellbeing is the degree to which their studies are subject to external lifestyle pressures. These pressures are relieved or exacerbated by choices students make around their approaches to study, and the amount of time they devote to work and leisure. This Chapter considers results from a 2012 survey of law students at the University of New South Wales (UNSW), Sydney, Australia. Those results are compared to results from a similar US law student survey, and comparable data from the UK and Australia more broadly. In addition, the UNSW study compares key lifestyle choices of undergraduate (LLB) and graduate (JD) law students. The significance of the analysis in this Chapter for understanding law students’ wellbeing is that comparing American and Australian law students’ lifestyle patterns provides insights into contextual variation between both groups, which is important to bear in mind when comparing American and Australian research on law students’ wellbeing, and appreciating the limits of such comparisons. In particular, much of the wellbeing literature to date has focused on course-based stressors, but in light of recent research indicating that improvements in students’ course-based experiences may not have a direct effect on law students’ elevated levels of psychological distress, it is important to understand the broader life pressures and stressors that may be impacting law students’ wellbeing.

Seismic passive earth pressures in soils

Seismic passive earth pressure coefficients were computed by the method of limit equilibrium using a pseudostatic approach for seismic forces. Composite curved rupture surfaces were considered in the analysis. While earlier studies using this type of analysis were mainly for sands, seismic passive earth pressure coefficients were obtained in the present study considering the effects of cohesion, surcharge, and own weight. The minimum seismic passive force was obtained by adding the individual minimum values of these components and the validity of the principle of superposition was examined. Other parameters considered in the analysis were wall batter angle, ground surface slope, soil friction angle, wall friction angle, wall adhesion to soil cohesion ratio, and horizontal and vertical seismic accelerations. The seismic earth pressure coefficients were found to be highly sensitive to the seismic acceleration coefficients both in the horizontal and vertical directions. Results of the study are presented in the form of figures and tables. Comparisons of the proposed method with available theories in the seismic case are also presented.

Vapor-liquid equilibrium data for the system n-heptane-n-butyl alcohol at medium pressures

Vapor-liquid equilibrium data for the system n-heptane-n-butyl alcohol at pressures of 1445, 2205, 2965, and 3725 mm. of Hg have been reported. The data are correlated with Chao's modified Redlich-Kister equation.

Vapor-liquid equilibrium data for the systems diisopropyl ether-n-heptane and diisopropyl ether-carbon tetrachloride at medium pressures

Vapor-liquid equilibrium data for the systems diisopropyl ether-n-heptane and diisopropyl ether-carbon tetrachloride have been reported at pressures of 760, 1520, and 2280 mm. of Hg. The systems form ideal mixtures under the pressure range studied.

Word-of-mouth -viestintään vaikuttavat tekijät Case: Agronomiliiton suosittelukampanja

Tämän tutkimuksen tavoitteena oli tarkastella laadullisten tutkimuskeinojen avulla keskeisten tekijöiden etenkin palkitsemisen vaikutusta word-of-mouth -viestintään. Teoriakatsauksen perusteella tutkimusaluetta lähestyttiin tarkastelemalla viittä eri aihealuetta, suosittelijan sisäistä motivaatiota, kokemusta tuotteen tai palvelun ominaisuuksista, suhdetta yrityksen kanssa ja suosituksen vastaanottajan kanssa sekä palkitsemista ja suosittelukampanjaa. Tutkimuksen teoreettisessa osuudessa avattiin käsite word-of-mouth -viestintä ja suosittelumarkkinointi sekä selvitettiin word-of-mouth -viestintään vaikuttavia keskeisiä tekijöitä, jotta suosittelupäätökseen liittyviä tekijöitä olemassa olevan tutkimustiedon avulla. Empiirinen tutkimus toteutettiin laadullisena tutkimuksena, jossa tutkimuksen casena oli Agronomiliitto ry:n suosittelukampanja. Tutkimuksessa haastateltiin Helsingin yliopiston maatalous-metsätieteellisen tiedekunnan syksyn 2009 tutoreita koskien heille suunnattua jäsenhankintakampanjaa. Kampanjan tarkoituksena oli saada tutorit suosittelemaan Agronomiliiton jäsenyyttä uusille opiskelijoille. Parhaiten kampanjassa menestyneet tutorit palkittiin. Kahdeksasta haastateltavasta seitsemän oli Agronomiliiton jäseniä. Haastateltavista kolme palkittiin hyvästä menestyksestä kampanjassa. Aineistonkeruumenetelmänä käytettiin puolistrukturoitua ja henkilökohtaista teemahaastattelua. Haastatteluissa pyrittiin ennen kaikkea selvittämään haastateltavien ajatuksia liittyen word-of-mouth -viestintään sekä suosittelusta palkitsemiseen. Tutkimus antaa suuntaa, että sisäisellä motivaatiotekijöillä on suuri merkitys suositteluviestinnän tapahtumiselle. Suosittelijan tulee tunnistaa suositeltavasta tuotteesta tai palvelusta koetut hyödyt. Suosittelua myös edesauttaa jos suosittelija omaa mielipidejohtajan ominaisuuksia. Palkitseminen toimii kannustimena suositella, mutta palkitsemisjärjestelmä tulee miettiä huolellisesti, jotta suosittelija ei koe suosittelun vähentävän omaa tai suositteluviestin uskottavuutta. Tutkimuksen tulokset viittaavat molempien, suosittelijan ja suosittelun vastaanottajan palkitsemisen olevan paras palkitsemisjärjestelmä suosittelukampanjassa.

Impulse-voltage breakdown characteristics of large gaps at low pressures

A study of the gap breakdown voltage characteristic at a low pressure of 7×10-5 Torr with a standard (1/50)-μsec impulse-voltage wave reveals an agreement with the criterion Vb=Cd0.5 suggested by Cranberg. Voltage-time-to-breakdown characteristics has also been determined. From these studies, it is concluded that impulse breakdown in vacuum is initiated by an electron current heating an anode spot and thereby liberating a clump which causes breakdown.

Elastic behaviour of matter under very high pressures - Uniform compression

In order to study the elastic behaviour of matter when subjected to very large pressures, such as occur for example in the interior of the earth, and to provide an explanation for phenomena like earthquakes, it is essential to be able to calculate the values of the elastic constants of a substance under a state of large initial stress in terms of the elastic constants of a natural or stress-free state. An attempt has been made in this paper to derive expressions for these quantities for a substance of cubic symmetry on the basis of non-linear theory of elasticity and including up to cubic powers of the strain components in the strain energy function. A simple method of deriving them directly from the energy function itself has been indicated for any general case and the same has been applied to the case of hydrostatic compression. The notion of an effective elastic energy-the energy require to effect an infinitesimal deformation over a state of finite strain-has been introduced, the coefficients in this expression being the effective elastic constants. A separation of this effective energy function into normal co-ordinates has been given for the particular case of cubic symmetry and it has been pointed out, that when any of such coefficients in this normal form becomes negative, elastic instability will set in, with associated release of energy.

Word-of-mouth-forskning – Från ett beteendevetenskapligt perspektiv mot ett företagsperspektiv

Syftet med denna artikel är att systematisera och analysera litteratur som anknyter till word-of-mouth-kommunikation (hädanefter WOM). Med konsumentdominerad marknadskommunikation avses att konsumenterna sinsemellan oberoende av företaget söker och sprider marknadsinformation. Den enda motsvarande litteraturanalys som förefaller att finnas publicerad är fyrtio år gammal (Arndt 1967). Sedan dess har det tillkommit en ansenlig mängd företagsekonomisk forskning som tydligt avviker från Johan Arndts, vilken huvudsakligen baserade sig den beteendevetenskapliga litteraturen.

An Experimental Study to Show the Effect of Thermal Stress on Thermal Contact Conductance at Sub-megapascal Contact Pressures

Experimental studies are presented to show the effect of thermal stresses on thermal contact conductance (TCC) at low contact pressures. It is observed that in a closed contact assembly, contact pressure acting on the interface changes with the changing temperature of contact members. This change in contact pressure consequently causes variations in the TCC of the junction. A relationship between temperature change and the corresponding magnitude of developed thermal stress in a contact assembly is determined experimentally. Inclusion of a term called temperature dependent load correction factor is suggested in the theoretical model for TCC to make it capable of predicting TCC values more accurately in contact assemblies that experience large temperature fluctuations. [DOI: 10.1115/1.4001615]