The cost performance and causes of overruns in infrastructure development projects in Asia

© 2019 The Author(s). Published by VGTU Pr. Infrastructure plays a major role in the economic development of countries, especially in Asia which has experienced tremendous growth in recent years. The procurement of infrastructure continues to be characterized by cost overruns resulting in significant academic interest and theoretical propositions on the influential factors. This study contributes to this issue through adoption of pragmatic research methodology involving deterministic statistical analysis of real project data from reports as well as a qualitative analysis of these reports to unearth underlying issues from a thematic analysis. Furthermore, the study design takes a multi-country view towards establishing the role of contextual and geographical influences on cost overrun. An evaluation of 102 major infrastructure projects was performed covering railways, roadways and energy sectors in different regions in Asia. Findings reveal that differences in the propensity for cost overrun are mostly dependent on a type of infrastructure with rail projects being the most likely to overrun budget. Theoretically, propositions on the influence of project contextual factors are tested highlighting the influence of project size, project type, geographical locations, and the length of implementation period of a project as well as factors related to political, economic, strategic, and competence in infrastructure delivery which vary across countries

A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles

In recent years, there has been a dramatic increase in the use of unmanned aerial vehicles (UAVs), particularly for small UAVs, due to their affordable prices, ease of availability, and ease of operability. Existing and future applications of UAVs include remote surveillance and monitoring, relief operations, package delivery, and communication backhaul infrastructure. Additionally, UAVs are envisioned as an important component of 5G wireless technology and beyond. The unique application scenarios for UAVs necessitate accurate air-to-ground (AG) propagation channel models for designing and evaluating UAV communication links for control/non-payload as well as payload data transmissions. These AG propagation models have not been investigated in detail when compared to terrestrial propagation models. In this paper, a comprehensive survey is provided on available AG channel measurement campaigns, large and small scale fading channel models, their limitations, and future research directions for UAV communication scenarios

Similarities and differences in PM10 and PM2.5 concentrations, chemical compositions and sources in Hefei City, China

Atmospheric particulates were sampled in Hefei City, China from October 2016 to January 2017 to compare chemical compositions and sources of PM2.5 (particle size smaller than 2.5 mu m) and PM10 (particle size smaller than 10 pm). The mean levels of PM2.5 and PM10 were 81 and 109 mu g/m(3), which are higher than the health threshold levels regulated by national and international standards. During the sampling period, AQI (Air Quality Index) was strongly correlated with PM2.5 (Pearson's coefficient r = 0.94) rather than PM10, concentrations. The PM2.5/PM10 ratios were approximately 0.7, revealing the characteristics of fine particle pollution. Pollution elements (S, Zn, Cu and Pb) took up a large proportion of the composition and had high enrichment factors of 437, 385, 20 and 53, respectively, in PM10. Coal combustion and high-tech manufacture industry discharges were suggested to be the main pollution sources of both PM2.5 and PM10. The PM2.5/PM10 ratios of anthropogenic element concentrations were much higher than ratios of earth crust element. As compared to PM10, S and Pb in PM2.5 had larger EFs, indicating that pollution elements were predominantly enriched in PM2.5. Furthermore, a paired sample t-test confirmed similar sources of PM2.5 and PM10. Our study provides basic database to evaluate the heavy metal pollution status of atmospheric particulates in Chinese cities

Levels, characteristics and health risk assessment of VOCs in differentfunctional zones of Hefei

In order to study the characteristics and health risk of VOCs in the ambient air in the typical developing cities in China, the research was conducted in five functional zones in Hefei from September 2016 to January 2017. The average concentrations of total measured VOCs in traffic zone was the largest (85.94 &mu;g m&minus;3), followed by industrial zone (64.84 &mu;g m&minus;3), development zone (58.92 &mu;g m&minus;3), resident zone (57.31 &mu;g m&minus;3), and background zone (54.94 &mu;g m&minus;3). Cl-VOCs were most abundant species in chlorinated VOCs (85.06%), which showed much higher level in industrial zone. the mean value of BTEX found in presented study was 65.19 &mu;g m&minus;3. Based on the specific VOC ratio method (B/T), the observed sites were greatly affected by the traffic emissions. The ratios of T/B, E/B and X/B were 1.15, 1.35 and 0.47, respectively, possibly due to the aging air mass. Carcinogenic risks for benzene, carbon tetrachloride, trichloroethylene, 1, 2-dichloroethane and chloroform were higher than the general acceptable risk level of 1.00 &times; 10&minus;6. Potential non-carcinogenic risk assessment showed that hazard quotient (HQ) of 10 VOCs not exceeded unity, but the hazard risk index (HI) at site ED, LY, YH and HD were both higher than 1.</p

Atmospheric pressure plasma treatments protect neural cells from ischemic stroke‐relevant injuries by targeting mitochondria

Most studies regarding plasma biomedicine applications mainly focus on the oxidative and/or nitrative stress on bacteria, cancer cells, and other treatment objects. In this study, we evaluate the protective effect of appropriate atmospheric pressure plasma jet (APPJ) treatments on oxygen and glucose deprivation (OGD)-induced neural cell apoptosis, which is a major pathological process during ischemic stroke, based on the physiological functions of NO. Results show that APPJ treatment reduces the OGD-induced apoptosis by weakening typical OGD injury consequences including loss of mitochondrial membrane potential, the release of cytochrome c from the mitochondria into the cytoplasm, lower antiapoptotic Bcl-2 expression, and upregulating the proapoptotic protein Bax. Furthermore, APPJ increased intracellular NO production, which is closely related to the cytoprotective effect of APPJ.</p