A PC-based inverse design method for radial and mixed flow turbomachinery

An Inverse Design Method suitable for radial and mixed flow turbomachinery is presented. The codes are based on the streamline curvature concept; therefore, it is applicable for current personal computers from the 286/287 range. In addition to the imposed aerodynamic constraints, mechanical constraints are imposed during the design process to ensure that the resulting geometry satisfies production consideration and that structural considerations are taken into account. By the use of Bezier Curves in the geometric modeling, the same subroutine is used to prepare input for both aero and structural files since it is important to ensure that the geometric data is identical to both structural analysis and production. To illustrate the method, a mixed flow turbine design is shown

Front propagation in random media: From extremal to activated dynamics

Front propagation in a random environment is studied close to the depinning threshold. At zero temperature we show that the depinning force distribution exhibits a universal behavior. This property is used to estimate the velocity of the front at very low temperature. We obtain a Arrhenius behavior with a prefactor depending on the temperature as a power law. These results are supported by numerical simulations.Comment: 6 pages, 2 figures, accepted in Int. J. Mod. Phys.

An acoustic gap between the NICU and womb: a potential risk for compromised neuroplasticity of the auditory system in preterm infants

The intrauterine environment allows the fetus to begin hearing low-frequency sounds in a protected fashion, ensuring initial optimal development of the peripheral and central auditory system. However, the auditory nursery provided by the womb vanishes once the preterm newborn enters the high-frequency (HF) noisy environment of the neonatal intensive care unit (NICU). The present article draws a concerning line between auditory system development and HF noise in the NICU, which we argue is not necessarily conducive to fostering this development. Overexposure to HF noise during critical periods disrupts the functional organization of auditory cortical circuits. As a result, we theorize that the ability to tune out noise and extract acoustic information in a noisy environment may be impaired, leading to increased risks for a variety of auditory, language, and attention disorders. Additionally, HF noise in the NICU often masks human speech sounds, further limiting quality exposure to linguistic stimuli. Understanding the impact of the sound environment on the developing auditory system is an important first step in meeting the developmental demands of preterm newborns undergoing intensive care

Universal depinning force fluctuations of an elastic line: Application to finite temperature behavior

The depinning of an elastic line in a random medium is studied via an extremal model. The latter gives access to the instantaneous depinning force for each successive conformation of the line. Based on conditional statistics the universal and non-universal parts of the depinning force distribution can be obtained. In particular the singular behavior close to a (macroscopic) critical threshold is obtained as a function of the roughness exponent of the front. We show moreover that the advance of the front is controlled by a very tenuous set of subcritical sites. Extension of the extremal model to a finite temperature is proposed, the scaling properties of which can be discussed based on the statistics of depinning force at zero temperature.Comment: submitted to Phys. Rev.

High school music classes enhance the neural processing of speech

Should music be a priority in public education? One argument for teaching music in school is that private music instruction relates to enhanced language abilities and neural function. However, the directionality of this relationship is unclear and it is unknown whether school-based music training can produce these enhancements. Here we show that 2 years of group music classes in high school enhance the neural encoding of speech. To tease apart the relationships between music and neural function, we tested high school students participating in either music or fitness-based training. These groups were matched at the onset of training on neural timing, reading ability, and IQ. Auditory brainstem responses were collected to a synthesized speech sound presented in background noise. After 2 years of training, the neural responses of the music training group were earlier than at pre-training, while the neural timing of students in the fitness training group was unchanged. These results represent the strongest evidence to date that in-school music education can cause enhanced speech encoding. The neural benefits of musical training are, therefore, not limited to expensive private instruction early in childhood but can be elicited by cost-effective group instruction during adolescence

An investigation into cyber security risk mitigation and the human factor in developing a cyber security culture - A comparative analysis of two maritime companies in Norway

The objective of this study is to conduct an analysis of two maritime companies located in Norway, investigating the participants knowledge and behaviours contributing as human factors shaping the companies cyber security culture. The aim for this research is to assess the risk mitigation measures implemented by the two selected companies in response to cyber threats. 5 employees from two separate companies were interviewed and there was performed an analysis on the results of 10 individual interviews. The results of the research show that there is a lot of information and guidelines regarding cyber security on the intranet of each company, however not all the employees check this site and therefore is not aware of the information and guidelines. In addition, communication from senior management regarding this issue is low and most of the information comes through the IT department. Also, it was detected that onboarding cyber security training was at high priority, however the yearly training and awareness courses varied. Based on findings the study proposes as solutions for a “cyber security champion” in every office in the organization to help improve the awareness and make sure that all of the employees understand the guidelines

Spirit baptism in the Pentecostal movement and the inauguration of the Kingdom of God

This thesis has endavoured to help bring some new perspectives on the classical Pentecostal teaching on baptism on the Holy Spirit and have a look at recent Pentecostal scholarship on the subject. The teaching that was so prominent in the early days of the movement, has later faded more away, and renewed interest may help to bring it back to the forefront. The research questions are about Spirit baptism, what it is, how it has been developed and how it is understood. Are the Pentecostals right in confirming a subsequent baptism for empowerment for service and witness, or is it merely initiatory into the faith? Could a potential reworking of the theological framework give credibility to the idea that it is a broad biblical metaphor, connecting various theological themes such as ecclesiology, eschatology and the Kingdom of God together? And if this is so, may it revitalize its importance and relevance for Pentecostals today? This is a literary research, consulting works of important scholars in the field to gain an overview of different perspectives and debates on the subject in question, and to give valuable insights into the research questions given. Hermeneutical considerations will be done, considering the interpretation from mainly a Pentecostal perspective. Our literary research concluded in there being various perspectives on Spirit baptism, even within the Pentecostal movement, although the classical teaching of a subsequent baptism for service and witness still is present, and several scholars agree with its connection to communal church life and eschatology. Frank Macchia provides a thoroughly framework for viewing Spirit baptism as constitutional for the Church, as well as the means by which the Kingdom is inaugurated, without neglecting its function as empowerment for individual believers

Effective toughness of heterogeneous brittle materials

A heterogeneous brittle material characterized by a random field of local toughness Kc(x) can be represented by an equivalent homogeneous medium of toughness, Keff. Homogenization refers to a process of estimating Keff from the local field Kc(x). An approach based on a perturbative expansion of the stress intensity factor along a rough crack front shows the occurrence of different regimes depending on the correlation length of the local toughness field in the direction of crack propagation. A `"weak pinning" regime takes place for long correlation lengths, where the effective toughness is the average of the local toughness. For shorter correlation lengths, a transition to "strong pinning" occurs leading to a much higher effective toughness, and characterized by a propagation regime consisting in jumps between pinning configurations

Material-independent crack arrest statistics: Application to indentation experiments

An extensive experimental study of indentation and crack arrest statistics is presented for four different brittle materials (alumina, silicon carbide, silicon nitride, glass). Evidence is given that the crack length statistics can be described by a universal (i.e. material independent) distribution. The latter directly derives from results obtained when modeling crack propagation as a depinning phenomenon. Crack arrest (or effective toughness) statistics appears to be fully characterized by two parameters, namely, an asymptotic crack length (or macroscopic toughness) value and a power law size dependent width. The experimental knowledge of the crack arrest statistics at one given scale thus gives access to its knowledge at all scales