Relaxation of writhe and twist of a bi-helical magnetic field

In the past few years suggestions have emerged that the solar magnetic field might have a bi-helical component with oppositely polarized magnetic fields at large and small scales, and that the shedding of such fields may be crucial for the operation of the dynamo. It is shown that, if a bi-helical field is shed into the solar wind, positive and negative contributions of the magnetic helicity spectrum tend to mix and decay. Even in the absence of turbulence, mixing and decay can occur on a time scale faster than the resistive one provided the two signs of magnetic helicity originate from a single tube. In the presence of turbulence, positively and negatively polarized contributions mix rapidly in such a way that the ratio of magnetic helicity to magnetic energy is largest both at the largest scale and in the dissipation range. In absolute units the small scale excess of helical fields is however negligible.Comment: 6 pages, 9 figures, to be published in Astron. Astrophy

Investigating the Role of Critical Success Factors in Achieving the Success of Agile Projects in the Gaza Strip

Achieving project success is a critical element of project management, and identifying the critical success factors (CSFs) that contribute to it is imperative. Agile project management has gained significant attention due to its flexibility, adaptability, and iterative approach, but achieving project success in agile projects remains a challenge. In order to identify the CSFs that have a significant impact on project outcomes, this study examines the role of CSFs in achieving project success in agile projects. A structured online questionnaire was used to collect data from 109 project managers and team members working on agile projects, which was then analyzed using various statistical methods. According to the study\u27s findings, seven factors significantly influence the success of projects: scope and cost management, leadership, agile analytics techniques, customer involvement, teamwork, planning and scheduling, and effective communication, which account for 71.9% of the total variance explained by the CSFs components. The analysis of Pearson correlation coefficients between CSFs and agile project outcomes indicates a positive correlation between each CSF and the four project outcomes (timeliness, cost, quality, and customer satisfaction). The regression analysis includes two significant predictors: scope and cost management, and planning and scheduling, explaining 67.7% of the variation in project outcomes. The findings provide valuable insights for project managers in the Gaza Strip to enhance project success with agile methods by focusing on CSFs

Exploring the Relationship between Green IT Awareness and Adoption: A Case Study of IT Students in the Gaza Strip

Green computing, also known as GIT, has emerged as a crucial field in response to environmental concerns. This study focuses on assessing the level of GIT awareness and adoption among IT students at Al-Aqsa University in Gaza, as well as examining the relationship between GIT awareness and adoption. Data was collected through an online questionnaire completed by 273 participants. The questionnaire covered various aspects of GIT awareness, including understanding, environmental awareness, and e-waste awareness. The collected data was analyzed using statistical techniques such as principal component analysis, mean, and standard deviation. The results indicated that students possessed a satisfactory level of understanding of GIT concepts and the reasons for its adoption. Furthermore, the findings highlighted the significant impact of GIT awareness factors, including GIT understanding, environmental awareness, and e-waste awareness, on GIT adoption. However, it was observed that students did not consistently adhere to GIT guidelines, particularly in terms of frequent internet access and extended computer usage. Interestingly, no significant relationship was found between GIT adoption and students' academic standing. These findings provide valuable insights into the current state of GIT awareness and adoption among IT students and underscore the need for further efforts to promote sustainable computing practices

A Comparison of Force and Pressure Coefficients on Dome, Cube and Prism Shaped Buildings due to Straight and Tornadic Wind Using Three Dimensional Computational Fluids Dynamics

Tornadoes induce very different wind forces than a straight-line (SL) wind. A suitably designed building for a SL wind may fail when exposed to a tornado-wind of the same wind speed. It is necessary to design buildings that are more resistant to tornadoes. Most studies have been conducted to investigate tornado forces on cubic, gable-roof and cylinder buildings. However, little attention has been paid to investigate tornado force on dome buildings; hence, further research is conducted in this study. The forces on a dome, cube and prisms were analyzed and compared using Computational Fluid Dynamics (CFD) for tornadic and SL winds. One typical tornado parameter was considered for comparison. The conclusions drawn from this study were illustrated in visualizations. The tornado force coefficients on the cube and prisms were larger than those on the dome by at least 90% in the x-y directions, and 140% in the z direction. The tornado pressure coefficients on cube and prisms were greater at least 200%. The force coefficients on cube and prisms due to SL wind were higher than those on the dome due to tornado wind by about 100% in the z-direction. The ratio of tangential (Vθ) to translational (Vt) velocity reported in recent studies is 10 or greater, which is larger than the field observation ratios. The influence of Vθ/Vt ratios on the tornado force coefficient for a cubic, prism and dome buildings were compared using a systematic study. The Vθ/Vt ratios were considered to be 1, 3, 6, and 8 for comparison. These ratios were very much in agreement with field observation ratios. The magnitudes of the forces were found to be larger for slower translation speed or higher Vθ/Vt ratios. For faster translation speeds or, lower Vθ/Vt ratio, the maximum force coefficients shifted to the left of the time history

Anisotropy of Alfv\'enic Turbulence in the Solar Wind and Numerical Simulations

We investigate the anisotropy of Alfv\'enic turbulence in the inertial range of slow solar wind and in both driven and decaying reduced magnetohydrodynamic simulations. A direct comparison is made by measuring the anisotropic second-order structure functions in both data sets. In the solar wind, the perpendicular spectral index of the magnetic field is close to -5/3. In the forced simulation, it is close to -5/3 for the velocity and -3/2 for the magnetic field. In the decaying simulation, it is -5/3 for both fields. The spectral index becomes steeper at small angles to the local magnetic field direction in all cases. We also show that when using the global rather than local mean field, the anisotropic scaling of the simulations cannot always be properly measured.Comment: 9 pages, 8 figure

Weak Alfvén-wave turbulence revisited

Weak Alfvénic turbulence in a periodic domain is considered as a mixed state of Alfvén waves interacting with the two-dimensional (2D) condensate. Unlike in standard treatments, no spectral continuity between the two is assumed, and, indeed, none is found. If the 2D modes are not directly forced, k−2 and k−1 spectra are found for the Alfvén waves and the 2D modes, respectively, with the latter less energetic than the former. The wave number at which their energies become comparable marks the transition to strong turbulence. For imbalanced energy injection, the spectra are similar, and the Elsasser ratio scales as the ratio of the energy fluxes in the counterpropagating Alfvén waves. If the 2D modes are forced, a 2D inverse cascade dominates the dynamics at the largest scales, but at small enough scales, the same weak and then strong regimes as described above are achieved