The History of the Name \u3ci\u3ePanorpa\u3c/i\u3e Linnaeus (Mecoptera)

(excerpt) Attempts to understand the origin of Linnaeus\u27 name for the scorpionfly Panorpa have come to nought for a very good reason. The word does not mean anything at all. It is an interesting example of the futility of looking up names in a Latin or Greek dictionary to find their meaning when the history of the word is at all complicated. The word Panorpa is born of a series of taxonomic, philological, grammatical, and (perhaps) typographical errors which can be sorted out by a survey of the pre-Linnaean history of the word and of the insect. In order to keep the end in view throughout the argument that follows, the reader may be gratified to anticipate the conclusion that Panorpa comes ultimately from the Greek word parnops (genitive parnopos) meaning \u27locust.\u2

The Etymology of the Names Pipunculus Latreille and Dorilas Meigen (Diptera, Pipunculidae)

(excerpt) There are at least two good reasons for understanding the etymology of scientific names. The first is to satisfy the natural curiosity about the history of the terms we use, and to gain an entree into the mind of the man ~.ho fist used a name. A study of Fabricius\u27 names, for instance, reveals that he had a playful sense of humor. Secondly, such understanding contributes to the stability of names, and helps to prevent irresponsible emendation of spelling, gender, or morphology such as burden the synonomies of most groups. It is happil

Analysis of Selective Laser Sintering print parameter modelling methodologies for energy input minimisation : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University, Albany, New Zealand

Additive Manufacturing (AM) is the name given to a series of processes used to create solids, layer upon layer, from 3 Dimensional (3D) models. As AM experiences rapid growth there exists an opportunity for Selective Laser Sintering (SLS) to expand into markets it has not previously accommodated. One of the ways SLS can accomplish this is by expanding the range of materials that can be processed into useful products, as currently only a small number of materials are available when compared to other AM technologies. One of the biggest barriers to the adoption of materials is the danger inherent to high-energy processes such as SLS. The aim of this research was to identify opportunities to improve current methods for modelling the relationship between material specifications, and printing parameters. This was achieved by identifying existing models used to determine printing parameters for a new material, identifying weaknesses in current modelling processes, conducting experimentation to explore the validity of these weaknesses, and exploring opportunities to improve the model to address these weaknesses. The current models to determine printer parameters to achieve successful sintering include both the Sintering Window (SW) and the Energy Melt Ratio (EMR). These two models are complementary, and both are required to establish all common print parameters. They include both thermal and physical powder properties, but do not include any optical properties. This is significant because the nature of the SLS printing process relies on concentrated delivery of laser energy to achieve successful sintering. Analysis of two similar polyamide powders, one black and one white, identified that the two powders were similar thermally and physically, which meant the models predicted that they should both sinter successfully utilizing the same set of print parameters. Results of the experimental trials showed that no trials involving the white powder sintered successfully, and trials involving the black powder suffered from issues with either insufficient energy to successfully remove parts without damage, or excessive energy causing excess powder to bond to the part. Further experimentation was carried out to investigate the differences in optical properties using Fourier Transform Infrared Spectroscopy (FTIR) and Spectrofluorophotometry. FTIR revealed that there was a difference in absorption as a material property, indicating that differences in laser energy absorption could explain the results seen in the trials. Spectrofluorophotometry revealed minimal differences in fluorescence of the powders, suggesting it an unlikely source of energy loss. Future work is recommended to research a standardised form of testing setup that can be used to categorize the reflectance of a material, as current work relies on proprietary experimental setups. Finding methods of classifying the laser absorption that is easily available to operators would enable refinement of the EMR equation to reflect the energy losses during printing, and remove another barrier for adoption of new materials

Addressing Integration Error for Polygonal Finite Elements Through Polynomial Projections: A Patch Test Connection

Polygonal finite elements generally do not pass the patch test as a result of quadrature error in the evaluation of weak form integrals. In this work, we examine the consequences of lack of polynomial consistency and show that it can lead to a deterioration of convergence of the finite element solutions. We propose a general remedy, inspired by techniques in the recent literature of mimetic finite differences, for restoring consistency and thereby ensuring the satisfaction of the patch test and recovering optimal rates of convergence. The proposed approach, based on polynomial projections of the basis functions, allows for the use of moderate number of integration points and brings the computational cost of polygonal finite elements closer to that of the commonly used linear triangles and bilinear quadrilaterals. Numerical studies of a two-dimensional scalar diffusion problem accompany the theoretical considerations

Origin of the hemispheric asymmetry of solar activity

The frequency spectrum of the hemispheric asymmetry of solar activity shows enhanced power for the period ranges around 8.5 years and between 30 and 50 years. This can be understood as the sum and beat periods of the superposition of two dynamo modes: a dipolar mode with a (magnetic) period of about 22 years and aquadrupolar mode with a period between 13 and 15 years. An updated Babcock-Leighton-type dynamo model with weak driving as indicated by stellar observations shows an excited dipole mode and a damped quadrupole mode in the correct range of periods. Random excitation of the quadrupole by stochastic fluctuations of the source term for the poloidal field leads to a time evolution of activity and asymmetry that is consistent with the observational results.Comment: Astronomy & Astrophysics, accepte

Are the strengths of solar cycles determined by converging flows towards the activity belts?

It is proposed that the observed near-surface inflows towards the active regions and sunspot zones provide a nonlinear feedback mechanism that limits the amplitude of a Babcock-Leighton-type solar dynamo and determines the variation of the cycle strength. This hypothesis is tested with surface flux transport simulations including converging latitudinal flows that depend on the surface distribution of magnetic flux. The inflows modulate the build-up of polar fields (represented by the axial dipole) by reducing the tilt angles of bipolar magnetic regions and by affecting the cross-equator transport of leading-polarity magnetic flux. With flux input derived from the observed record of sunspot groups, the simulations cover the period between 1874 and 1980 (corresponding to solar cycles 11 to 20). The inclusion of the inflows leads to a strong correlation of the simulated axial dipole strength during activity minimum with the observed amplitude of the subsequent cycle. This in agreement with empirical correlations and in line with what is expected from a Babcock-Leighton-type dynamo. The results provide evidence that the latitudinal inflows are a key ingredient in determining the amplitude of solar cycles.Comment: accepted in A&

Inflows towards active regions and the modulation of the solar cycle: a parameter study

Aims: We aim to investigate how converging flows towards active regions affect the surface transport of magnetic flux, as well as their impact on the generation of the Sun's poloidal field. The inflows constitute a potential non-linear mechanism for the saturation of the global dynamo and may contribute to the modulation of the solar cycle in the Babcock-Leighton framework. Methods: We build a surface flux transport code incorporating a parametrized model of the inflows and run simulations spanning several cycles. We carry out a parameter study to assess how the strength and extension of the inflows affect the build-up of the global dipole field. We also perform simulations with different levels of activity to investigate the potential role of the inflows in the saturation of the global dynamo. Results: We find that the interaction of neighbouring active regions can lead to the occasional formation of single-polarity magnetic flux clumps inconsistent with observations. We propose the darkening caused by pores in areas of high magnetic field strength as a plausible mechanism preventing this flux-clumping. We find that inflows decrease the amplitude of the axial dipole moment by a $\sim30\,\%$, relative to a no-inflows scenario. Stronger (weaker) inflows lead to larger (smaller) reductions of the axial dipole moment. The relative amplitude of the generated axial dipole is about $9\%$ larger after very weak cycles than after very strong cycles. This supports the inflows as a non-linear mechanism capable of saturating the global dynamo and contributing to the modulation of the solar cycle within the Babcock-Leighton framework

Surface flux transport simulations: Effect of inflows toward active regions and random velocities on the evolution of the Sun's large-scale magnetic field

Aims: We aim to determine the effect of converging flows on the evolution of a bipolar magnetic region (BMR), and to investigate the role of these inflows in the generation of poloidal flux. We also discuss whether the flux dispersal due to turbulent flows can be described as a diffusion process. Methods: We developed a simple surface flux transport model based on point-like magnetic concentrations. We tracked the tilt angle, the magnetic flux and the axial dipole moment of a BMR in simulations with and without inflows and compared the results. To test the diffusion approximation, simulations of random walk dispersal of magnetic features were compared against the predictions of the diffusion treatment. Results: We confirm the validity of the diffusion approximation to describe flux dispersal on large scales. We find that the inflows enhance flux cancellation, but at the same time affect the latitudinal separation of the polarities of the bipolar region. In most cases the latitudinal separation is limited by the inflows, resulting in a reduction of the axial dipole moment of the BMR. However, when the initial tilt angle of the BMR is small, the inflows produce an increase in latitudinal separation that leads to an increase in the axial dipole moment in spite of the enhanced flux destruction. This can give rise to a tilt of the BMR even when the BMR was originally aligned parallel to the equator

Platform-basin transitions and their role in Alpine-style collision systems : a comparative approach

CB acknowledges financial support from Optimus (Aberdeen) ltd. Petroceltic International plc are thanked for providing access to the subsurface data used in this study and for permission to publish images used here. Schlumberger are thanked for providing use of Petrel software under their academic agreement with the University of Aberdeen. RWHB thanks the organisers of the 12th Emile Argand Conference on Alpine Geological Studies for the invitation and financial support to participate in the Montgenevre workshop. Reviewers Enrico Tavarnelli, Thierry Dumont and editors Christian Sue and Stefan Schmid are all thanked for their comments that have significantly improved this contribution.Peer reviewedPublisher PD