Energy Complexity for Sorting Algorithms in Java

This study extends the concept of time complexity to energy, i.e., energy complexity, by showing a strong correlation between time complexity and energy consumption for sorting algorithms: Bubble Sort, Counting Sort, Merge Sort and Quick Sort, written in Java and run on single kernels. We investigate the correlation between wall time and time complexity, as well as the correlation between energy consumption and wall time. The primary finding is that time complexity can be used as a guideline to estimate the energy consumption of O(n*n), O(nlog(n)) and O(n + k) sorting algorithms. The secondary finding is that the inputs producing the theoretical worst cases for Merge Sort and Bubble Sort did not produce the worst case wall time nor the worst case energy consumption

Study of the microstructure resulting from brazed aluminium materials used in heat exchangers

Re-solidification of AA4343 cladding after brazing as well as the related precipitation in the modified AA3003 core material have been investigated. Analysis of the re-solidified material showed that partial dissolution of the core alloy occurs in both the brazing joints and away of them. Far from the brazing joints, the dissolution is, however, limited and diffusion of silicon from the liquid into the core material leads to solid-state precipitation in the so-called “band of dense precipitates” (BDP). On the contrary, the dissolution is enhanced in the brazing joint to such an extent that no BDP could be observed. The intermetallic phases present in the resolidified areas as well as in the core material have been analyzed and found to be mainly cubic alpha-Al(Mn,Fe)Si. These results were then compared to predictions made with available phase diagram information

Dilute ferrimagnetic semiconductors in Fe-substituted spinel ZnGa2_2O4_4

Solid solutions of nominal composition [ZnGa$_2$O$_4$]$_{1-x}$[Fe$_3$O$_4$]$_x$, of the semiconducting spinel ZnGa$_2$O$_4$ with the ferrimagnetic spinel Fe$_3$O$_4$ have been prepared with $x$ = 0.05, 0.10, and 0.15. All samples show evidence for long-range magnetic ordering with ferromagnetic hysteresis at low temperatures. Magnetization as a function of field for the $x$ = 0.15 sample is S-shaped at temperatures as high as 200 K. M\"ossbauer spectroscopy on the $x$ = 0.15 sample confirms the presence of Fe$^{3+}$, and spontaneous magnetization at 4.2 K. The magnetic behavior is obtained without greatly affecting the semiconducting properties of the host; diffuse reflectance optical spectroscopy indicates that Fe substitution up to $x$ = 0.15 does not affect the position of the band edge absorption. These promising results motivate the possibility of dilute ferrimagnetic semiconductors which do not require carrier mediation of the magnetic moment.Comment: 9 pages and 6 figure

Numerical evolution of multiple black holes with accurate initial data

We present numerical evolutions of three equal-mass black holes using the moving puncture approach. We calculate puncture initial data for three black holes solving the constraint equations by means of a high-order multigrid elliptic solver. Using these initial data, we show the results for three black hole evolutions with sixth-order waveform convergence. We compare results obtained with the BAM and AMSS-NCKU codes with previous results. The approximate analytic solution to the Hamiltonian constraint used in previous simulations of three black holes leads to different dynamics and waveforms. We present some numerical experiments showing the evolution of four black holes and the resulting gravitational waveform.Comment: Published in PR

Design, Characterization and Investigation of Heavy Metal Ions Removal by New Cellulose-Ether Based adsorbent

The present investigation deals with the elaboration in homogenous conditions of new cross-linked, hydroxyl cellulose (HEC) based material. Further, its application as a new eco-friendly low-cost efficient adsorbent of hazardous metal ions from an aquatic environment is treated. In this respect, the functionalization of HEC has been carried out using EDTA as a cross-linking agent exploiting its high capacity to chelate heavy metal ions in aqueous solutions. The proposed structure of the new crosslinked material (HECD) was investigated using structural analyses (FTIR-ATR vibrational spectroscopy and CP/MAS 13C NMR Spectroscopy). Also, the thermal and crystalline behaviours of unmodified and modified HEC were studied using thermogravimetric (TG and DTG) and DRX patterns. In addition, SEM images were recorded to demonstrate the changes expected at the morphological and textural level. Furthermore, the adsorption capacity of Pb (II), Cu (II), Cd (II) and Zn (II) ions from aqueous solutions by HECD was investigated using batch technique and optimized according to metal concentration, pH, contact time, ionic selectivity and regenerability. The maximum metal uptakes under optimum conditions were of 1.96, 4.18, 1.81 and 1.66 mmol/g for Pb (II), Cu (II), Cd (II) and Zn (II), respectively. Thus, to examine the mechanism of adsorption, the experimental data is fitted to kinetic, isothermal, and thermodynamic modelling

A new set of integrals of motion to propagate the perturbed two-body problem

A formulation of the perturbed two-body problem that relies on a new set of orbital elements is presented. The proposed method represents a generalization of the special perturbation method published by Peláez et al. (Celest Mech Dyn Astron 97(2):131?150,2007) for the case of a perturbing force that is partially or totally derivable from a potential. We accomplish this result by employing a generalized Sundman time transformation in the framework of the projective decomposition, which is a known approach for transforming the two-body problem into a set of linear and regular differential equations of motion. Numerical tests, carried out with examples extensively used in the literature, show the remarkable improvement of the performance of the new method for different kinds of perturbations and eccentricities. In particular, one notable result is that the quadratic dependence of the position error on the time-like argument exhibited by Peláez?s method for near-circular motion under the J2 perturbation is transformed into linear.Moreover, themethod reveals to be competitive with two very popular elementmethods derived from theKustaanheimo-Stiefel and Sperling-Burdet regularizations

Baseline Neurocognitive Performance and Symptoms in Those With Attention Deficit Hyperactivity Disorders and History of Concussion With Previous Loss of Consciousness

Previous consensus statements on sports concussion have highlighted the importance of Attention Deficit Hyperactivity Disorder (ADHD) and loss of consciousness (LOC) as risk factors related to concussion management. The present study investigated how self-reported history of either ADHD diagnosis or history of previous concussion resulting in LOC influence baseline neurocognitive performance and self-reported symptoms. This analysis was performed retrospectively on data collected primarily from student-athletes, both Division 1 and club sports athletes. The dataset (n = 1460) is comprised of college students (age = 19.1 ± 1.4 years). Significant differences were found for composite scores on the ImPACT for both history of concussion (p = 0.016) and ADHD (p = 0.014). For concussion history, those with a previous concussion, non-LOC, performed better on the visual motor speed (p = 0.004). Those with diagnosis of ADHD performed worse on verbal memory (p = 0.001) and visual motor speed (p = 0.033). For total symptoms, concussion history (p < 0.001) and ADHD (p = 0.001) had an influence on total symptoms. Those with ADHD reported more symptoms for concussion history; those with previous LOC concussion reported more symptoms than those with non-LOC concussion (p = 0.003) and no history (p < 0.001). These results highlight the importance of baseline measures of neurocognitive function and symptoms in concussion management in order to account for pre-existing conditions such as ADHD and LOC from previous concussion that could influence these measures

Levi-Civita,Tullio

International audienceTullio Levi-Civita (29 March 1873 to 29 December 1941) has been an Italian mathematician and mathematical physicist, known above all for his work on the absolute differential calculus. Levi-Civita came from a rigorous and creative school of mathematical physicists and was a pupil of Gregorio Ricci-Curbastro. LeviCivita’s work included outstanding results in pure and applied mathematics and in celestial and analytic mechanics but also celebrated textbooks. These last, even those written in Italian, have influenced mathematical physicists all over the world.Levi-Civita has perfected some conceptual tools of great importance in modern science, particularly in general relativity, number theory, and continuum mechanics