The NISPAcee journal of public administration and policy

This paper introduces a new approach for conducting project feasibility study by embracing the principles of sustainable development. Construction projects, in particular, infrastructures have major influence on the attainment of sustainable development, thus project sustainability needs to be considered. This becomes a pressing issue particularly in those developing countries or regions, such as China where a huge amount of construction works are currently performed and remain to happen in the future. Previous study has addressed little on the relevance of project feasibility study to project sustainability performance. The importance of incorporating sustainable development principles in conducting project feasibility study is not effectively understood by project stakeholders. This paper addresses major challenges of undertaking project feasibility study in line with sustainable construction practice with reference to the Chinese construction industry. A case study approach is the major research method in this study. The research team collected 87 feasibility study reports from various projects. Attributes are used for measuring project performance, including 18 economic performance attributes, nine social performance attributes, and eight environmental performance attributes. Research results show that economic performance is given the most concern in the current practice of project feasibility study, whilst less attention is given to the social and environmental performance. The study reveals the insufficiency of examining the performance of implementing a construction project from the perspective of sustainable development. The results also suggest the need for shifting the traditional approach of project feasibility study to a new approach that embraces the principles of sustainable development

Wireless secrecy under multivariate correlated Nakagami-m fading

Current wireless secrecy research in the literature has mainly been performed for one wiretapper under correlated fading. In this paper, a new wireless secrecy framework for multiple wiretappers under multivariate exponentially-correlated (exp.c.) Nakagami-m fading is proposed. Using the distribution of multivariate exp.c. Nakagami-m fading, new, exact, and compact expressions for the ergodic secrecy capacity, and secrecy outage probability (SOP) under multiple wiretappers are obtained for an integer fading parameter m. A secrecy analysis is also performed for the first time in this paper using an adaptive on/off transmission encoder under multivariate exp.c. Nakagami-m fading. A secrecy analysis with three wiretappers under quadrivariate exp.c. Nakagami-m fading is also given, which shows the effectiveness of the new framework. Simulation results are shown to exactly match theoretical predictions

Comparative response spectrum analysis on 15- and 50-story reinforced concrete buildings having shear walls with and without openings as per EN1998-1 Seismic Code

Medium-rise reinforced concrete (RC) framed apartment complexes with stories ranging from 15 to 50 are becoming more common in Ethiopia’s main cities. In these RC-framed structures, shear walls are included for lateral load resistance. As apertures are frequently provided in shear walls, it is critical to evaluate their influence on story drift, stiffness, shear and moments, and stress within the shear walls. A 3D study with five different cases was carried out with ETABS version 19.00 software to investigate the influence of apertures in a building’s shear wall. This study looks at the effects of changing the size and location of these apertures. Based on this analysis, extensive data were acquired, and useful conclusions were formed that will be useful to practicing engineers. The seismic parameter utilized for the response spectrum study was Building Code of Ethiopia ES8-15, which conforms to Eurocode 8-2004 seismic code guidelines (based on EN1998-1) with target response spectrum type-I. The following parameters were used: ground acceleration, ag/g = 0.1, spectrum type = I, ground type = B, soil factor, S = 1.35, spectrum period, Tb, = 0.05 s, spectrum period, Tc = 0.25 s, spectrum period, Td = 1.2 s, lower bound factor, beta = 0.2, behavior factor = 1, and damping ratio = 5%. The outcomes are compared using various parameters such as displacement, story drift, story stiffness, story shear, and story moment both with and without shear wall opening cases. This study will give tremendous insight into the effect of shear wall openings on the performance of the structure. The analysis in this work was carried out on a linear model, which may not represent the complete local response of the structure; thus, future researchers should perform nonlinear analysis based on a performance-based design. It was concluded from this investigation that incorporating shear walls considerably enhanced the performance of the building over framed structures. Shear wall openings in a structure have a significant influence on the building’s performance. Due to their significant resistance to earthquake forces, shear wall structures are highly recommended for seismic hazard zones

Complexity and Intermittent Turbulence in Space Plasmas

Sporadic and localized interactions of coherent structures arising from plasma resonances can be the origin of "complexity" of the coexistence of non- propagating spatiotemporal fluctuations and propagating modes in space plasmas. Numerical simulation results are presented to demonstrate the intermittent character of the non-propagating fluctuations. The technique of the dynamic renormalization-group is introduced and applied to the study of scale invariance of such type of multiscale fluctuations. We also demonstrate that the particle interactions with the intermittent turbulence can lead to the efficient energization of the plasma populations. An example related to the ion acceleration processes in the auroral zone is provided

High-Energy emissions from the Pulsar/Be binary system PSR J2032+4127/MT91 213

PSR J2032+4127 is a radio-loud gamma-ray-emitting pulsar; it is orbiting around a high-mass Be type star with a very long orbital period of 25-50years, and is approaching periastron, which will occur in late 2017/early 2018. This system comprises with a young pulsar and a Be type star, which is similar to the so-called gamma-ray binary PSR~B1259-63/LS2883. It is expected therefore that PSR J2032+4127 shows an enhancement of high-energy emission caused by the interaction between the pulsar wind and Be wind/disk around periastron. Ho et al. recently reported a rapid increase in the X-ray flux from this system. In this paper, we also confirm a rapid increase in the X-ray flux along the orbit, while the GeV flux shows no significant change. We discuss the high-energy emissions from the shock caused by the pulsar wind and stellar wind interaction and examine the properties of the pulsar wind in this binary system. We argue that the rate of increase of the X-ray flux observed by Swift indicates (1) a variation of the momentum ratio of the two-wind interaction region along the orbit, or (2) an evolution of the magnetization parameter of the pulsar wind with the radial distance from the pulsar. We also discuss the pulsar wind/Be disk interaction at the periastron passage, and propose the possibility of formation of an accretion disk around the pulsar. We model high-energy emissions through the inverse-Compton scattering process of the cold-relativistic pulsar wind off soft photons from the accretion disk.Comment: 18 pages, 23 figures, 1 Table, accepted for publication in Ap

Advanced progress in recycling municipal and construction solid wastes for manufacturing sustainable construction materials

The sharply increasing solid waste generation has raised the environmental concerns worldwide which currently have been escalated to a worrying level. Intending to eliminate the negative environmental impacts of solid waste and meanwhile promote sustainability on the energy- and resource-intensive construction and building sector, considerable efforts have been devoted to recycling solid waste for the possible use in sustainable construction material products. This paper reviews the existing studies on recycling municipal and construction solid waste for the manufacture of geopolymer composites. Special attention is paid to the predominate performance of these geopolymer composite products. The principal findings of this work reveal that municipal and construction solid waste could be successfully incorporated into geopolymer composites in the forms of precursor, aggregate, additive, reinforcement fiber, or filling material. Additionally, the results indicate that although the inclusion of such waste might depress some of the attributes of geopolymer composites, proper proportion design and suitable treatment technique could alleviate these detrimental effects and further smooth the recycling progress. Finally, a brief discussion is provided to identify the important needs in the future research and development for promoting the utilization of solid waste materials in the forthcoming sustainable geopolymer industry. In summary, this work offers guidance for the better ecological choice to municipal and construction solid waste through developing waste materials into highly environmental-friendly construction materials

The X-ray modulation of PSR J2032+4127/MT91 213 during the Periastron Passage in 2017

We present the Neil Gehrels Swift Observatory (Swift), Fermi Large Area Telescope (Fermi-LAT), and Karl G. Jansky Very Large Array (VLA) observations of the gamma-ray binary PSR J2032+4127/MT91 213, of which the periastron passage has just occurred in November 2017. In the Swift X-ray light curve, the flux was steadily increasing before mid-October 2017, however, a sharp X-ray dip on a weekly time-scale is seen during the periastron passage, followed by a post-periastron X-ray flare lasting for ~20 days. We suggest that the X-ray dip is caused by (i) an increase of the magnetization parameter at the shock, and (ii) the suppression due to the Doppler boosting effect. The 20-day post-periastron flare could be a consequence of the Be stellar disk passage by the pulsar. An orbital GeV modulation is also expected in our model, however, no significant variability is seen in the Fermi-LAT light curve. We suspect that the GeV emission resulted from the interaction between the binary's members is hidden behind the bright magnetospheric emission of the pulsar. Pulsar gating technique would be useful to remove the magnetospheric emission and recover the predicted GeV modulation, if an accurate radio timing solution over the periastron passage is provided in the future.Comment: 6 pages, including 2 figures. Accepted for publication in Ap