224 research outputs found
Assessing the Barriers and Risks to Private Sector Participation in Infrastructure Construction Projects in Developing Countries of Middle East
In developing countries, governments are often unable to implement urban infrastructure construction projects (UICPs) on their own, mainly due to budget and financial resource limitations. The participation of the private sector, through public–private partnerships (PPPs), has been considered as an alternative effective method for increasing the efficiency and productivity of urban infrastructure development. However, in many developing countries such as those situated in the Middle East, attracting private sector investments for UICPs uncovers profound challenges that have not ever been comprehensively accounted for and prioritized. To fill this knowledge gap, this study seeks to determine and prioritize the major barriers and risks faced by governments and urban managers in attracting private sector investments through the PPP schemes launched by developing countries in the Middle East. Based on a Delphi study conducted in Iran as an example, the opinions of 60 UICPs experts in both the public and private sectors were collected and analyzed. Results show that technical and organizational barriers and risks were perceived as the most important to private sector participation, followed by economic and financial barriers and risks, and then political and legal barriers and risk
Identification and Prioritization of Critical Risk Factors of Commercial and Recreational Complex Building Projects: A Delphi Study Using the TOPSIS Method
Construction development of Commercial and Recreational Complex Building Projects (CRCBPs) is one of the community needs of many developing countries. Since the implementation of these projects is usually very costly, identifying and evaluating their Critical Risk Factors (CRFs) are of significant importance. Therefore, the current study aims to identify and prioritize CRFs of CRCBPs in the Iranian context. A descriptive-survey method was used in this research; the statistical population, selected based on the purposive sampling method, includes 30 construction experts with hands-on experience in CRCBPs. A questionnaire related to the risk identification stage was developed based on a detailed study of the research literature and also using the Delphi survey method; 82 various risks were finally identified. In order to confirm the opinions of experts in identifying the potential risks, Kendall’s coefficient of concordance was used. In the first stage of data analysis, qualitative evaluation was performed by calculating the severity of risk effect and determining the cumulative risk index, based on which 25 CRFs of CRCBPs were identified for more accurate evaluation. At this stage, the identified CRFs were evaluated based on multi-criteria decision-making techniques and using the TOPSIS technique. Results show that the ten CRFs of CRCBPs are external threats from international relations, exchange rate changes, bank interest rate fluctuations, traffic licenses, access to skilled labor, changes in regional regulations, the condition of adjacent buildings, fluctuations and changes in inflation, failure to select a suitable and qualified consultant, and employer’s previous experiences and records. Obviously, the current study’s results and findings can be considered by CRCBPs in both the private and public sectors for proper effective risk identification, evaluation, and mitigatio
Assessing the resilience of a river management regime: Informal learning in a shadow network in the Tisza River Basin
Global sources of change offer unprecedented challenges to conventional river management strategies, which no longer appear capable of credibly addressing a trap: the failure of conventional river defense engineering to manage rising trends of disordering extreme events, including frequency and intensity of floods, droughts, and water stagnation in the Hungarian reaches of the Tisza River Basin. Extreme events punctuate trends of stagnation or decline in the ecosystems, economies, and societies of this river basin that extend back decades, and perhaps, centuries. These trends may be the long-term results of defensive strategies of the historical river management regime that reflect a paradigm dating back to the Industrial Revolution: "Protect the Landscape from the River." Since then all policies have defaulted to the imperatives of this paradigm such that it became the convention underlying the current river management regime. As an exponent of this convention the current river management regimes' methods, concepts, infrastructure, and paradigms that reinforce one another in setting the basin's development trajectory, have proven resilient to change from wars, political, and social upheaval for centuries. Failure to address the trap makes the current river management regimes resilience appear detrimental to the regions future development prospects and prompts demand for transformation to a more adaptive river management regime. Starting before transition to democracy, a shadow network has generated multiple dialogues in Hungary, informally exploring the roots of this trap as part of a search for ideas and methods to revitalize the region. We report on how international scientists joined one dialogue, applying system dynamics modeling tools to explore barriers and bridges to transformation of the current river management regime and develop the capacity for participatory science to expand the range of perspectives that inform, monitor, and revise learning, policy, and the practice of river management
Emergence of Multidrug Resistance and Metallo‑beta‑lactamase Producing Acinetobacter baumannii Isolated from Patients in Shiraz, Iran
Background: Metallo‑beta‑lactamase (MβL) enzymes production is one of the most important resistance mechanisms against carbapenems in some bacteria including Acinetobacter baumannii. Aims: This study was aimed to determine the antimicrobial susceptibility and the prevalence of MβL among carbapenem‑resistant isolates of A. baumannii. Materials and Methods: In this cross‑sectional study from October 2012 to April 2013, 98 isolates were identified as A. baumannii using Microgen™ kits and confirmed by molecular method. These isolates were tested for antimicrobial susceptibilities by disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines. Carbapenem‑resistant isolates were further detected phenotypically by MβL minimal inhibitory concentration (MIC)‑test strips, and subsequently positive MβL isolates were confirmed by polymerase chain reaction (PCR). Results: Overall, 98% (96/98) of A. baumannii isolates were detected as carbapenem‑resistant by MIC test. Highest sensitivity to the tested antibiotic with 42.9% (42/98) was observed to colistin. Of 96 carbapenem‑resistant isolates, 43 were phenotypically positive for MβL; out of 43 isolates, 37 were confirmed for the presence of MβL genes by PCR. Conclusion: The frequency of drug resistance among the clinical samples of A. baumannii isolated in our study against most of the antibiotics was very high. Moreover, all MβL producing isolates were multidrug resistance. Therefore, systematic surveillance to detect MβL producing bacteria and rational prescription and use of carbapenems could be helpful to prevent the spread of carbapenem resistance.Keywords: Acinetobacter baumannii, Antibiotic resistance, Carbapenem, Iran, Metallo‑beta‑lactamas
Systemic and stratum corneum biomarkers of severity in infant atopic dermatitis include markers of innate and T helper cell-related immunity and angiogenesis
BACKGROUND: Biomarkers of atopic dermatitis (AD) are largely lacking, especially in infant AD. Those that have been examined to date have focused mostly on serum cytokines with few on non-invasive biomarkers in the skin. OBJECTIVES: We aimed to explore biomarkers obtainable from non-invasive sampling of infant skin. We compared these to plasma biomarkers and structural and functional measures of the skin barrier. METHODS: We recruited 100 infants at first presentation with AD, who were treatment naïve to topical or systemic anti-inflammatory therapies and 20 healthy children. We sampled clinically unaffected skin by tape stripping the stratum corneum (SC). Multiple cytokines and chemokines and natural moisturizing factors (NMF) were measured in the SC and plasma. We recorded disease severity and skin barrier function. RESULTS: 19 SC and 12 plasma biomarkers showed significant difference between healthy and AD skin. Some biomarkers were common to both the SC and plasma, and others were compartment-specific. Identified biomarkers of AD severity included Th2 skewed markers (IL-13, CCL17, CCL22, IL-5), markers of innate activation (IL-18, Il-1α, IL1β, CXCL8), angiogenesis (Flt-1, VEGF) and others (sICAM-1, vCAM-1, IL-16, IL-17A). CONCLUSIONS: We identified clinically relevant biomarkers of AD, including novel markers, easily sampled and typed in infants. These markers may provide objective assessment of disease severity and suggest new therapeutic targets, or response measurement targets for AD. Future studies will be required to determine if these biomarkers, seen in very early AD, can predict disease outcomes or comorbidities
Enhanced efficiency and environmental stability of planar perovskite solar cells by suppressing photocatalytic decomposition
The environmental instability of perovskite solar cells caused by the ultraviolet photocatalytic effect of metal
oxide layers is a critical issue that must be solved. In this paper, we report improved environmental stability
of ZnO film-based planar heterojunction perovskite solar cells, by suppressing photocatalytic activities
induced by the ZnO electron transfer layer. The photovoltaic performance and stability in an ambient
environment under continuous illumination are effectively improved by applying an aluminum oxide
interlayer on the ZnO film to suppress the photocatalytic degradation of perovskites. The highest
efficiency of solar cells has increased from 14.62% to 17.17%, and after 250 h of continuous exposure
under full spectrum simulated sunlight in air, the efficiency remains as high as 15.03%. The results
suggest that effective suppression of photocatalytic degradation of perovskites with a modified electron
transfer layer is a new solution to improve the long-term environmental stability of perovskite solar cells
A systematic taxonomic review of the application of BIM and digital twins technologies in the construction industry
PurposeThis study provides a comprehensive analysis of the transition from Building Information Modelling (BIM) to digital twins (DT) in the construction industry. Specifically, the research explores the current state (themes and trends) and future directions of this emerging research domain.Design/methodology/approachA multi-stage approach was employed that combines scientometric and systematic review approaches. The scientometric analysis involves quantitative assessment of scientific publications retrieved from the Web of Science database – using software tools like VOSviewer and HistCite. The systematic review involved a rigorous synthesis and evaluation of the existing literature to identify research gaps, themes, clusters and future directions. Clusters obtained from the scientometric analysis of the co-occurrence network were then used as a subject base for a systematic study.FindingsEmergent findings reveal a rapidly growing interest in BIM-DT integration, with over 90% of publications since 2020. The United Kingdom, China and Italy are the leading contributing countries. Five prominent research clusters identified are: (1) Construction 4.0 technologies; (2) smart cities and urban environments; (3) heritage BIM and laser scanning; (4) asset and facility management; and (5) energy and sustainability. The study highlights the potential of BIM-DT integration for enhancing project delivery, asset management and sustainability practices in the built environment. Moreover, the project’s life cycle operation phase has garnered the most attention from researchers in this field compared to other phases.Originality/valueThis unique study is comprehensive in its approach by combining scientometric and systematic methods to provide a quantitative and qualitative evaluation of the BIM-DT research landscape. Unlike previous reviews that focused solely on facility management, this study’s scope covers the entire construction sector. By identifying research gaps, challenges and future directions, this study establishes a solid foundation for researchers exploring this emerging field and envisions the future landscape of BIM-DT integration in the built environment
Determining the Essential Criteria for Choosing Appropriate Methods for Maintenance and Repair of Iraqi Healthcare Building Facilities
Today, building maintenance and repair (M&R) is a neglected aspect of the construction business throughout a building’s entire life cycle. Selecting appropriate M&R strategies is crucial, particularly for emerging economies like Iraq with severely constrained resources. This study seeks to identify the primary selection criteria for M&R methods of healthcare building facilities (HBFs) in Iraq. A comprehensive desktop literature analysis was undertaken to extract and determine the essential selection criteria for the most suited M&R approaches to buildings in general. Then, two rounds of the Delphi survey were conducted to consolidate the specific selection criteria to suit the circumstances of Iraq and HBFs. A total of 21 sub-criteria were identified and divided into six main groups. The main criteria and the associated sub-criteria were then analyzed and ranked using the fuzzy analytic hierarchy process (FAHP) technique. The ranking of the various main criteria revealed that the “cost” criterion was ranked first in terms of importance, followed by the “human resources” and “quality” criteria. The fourth, fifth, and sixth main criteria are “reliability/flexibility”, “safety/risk/environment”, and “facilities/technology”, respectively. The overall ranking of the sub-criteria placed “optimization and cost reduction” in the first position and “extending the life of the equipment and preserving their initial quality” in the bottom place. It is anticipated that the key findings and effective recommendations of this study will considerably contribute to the improvement of building maintenance and repair management practices in developing nations while enhancing different stakeholders’ understanding of the most important selection criteria for M&R methods, particularly with regard to healthcare building facilities in Iraq
Mesoporous PbI2 assisted growth of large perovskite grains for efficient perovskite solar cells based on ZnO nanorods
Perovskite solar cells (PSCs) have attracted great attention due to their low cost and high power conversion efficiency (PCE). However, the defects and grain boundaries in perovskite films dramatically degrade their performance. Here, we show a two-step annealing method to produce mesoporous PbI2 films for growth of continuous, pinhole-free perovskite films with large grains, followed by additional ethanol vapor annealing of perovskite films to reduce the defects and grain boundaries. The large perovskite grains dramatically suppress the carrier recombination, and consequently we obtain ZnO-nanorod-based PSCs that exhibit the best efficiency of 17.3%, with high reproducibility
Interface engineering of high efficiency perovskite solar cells based on ZnO nanorods using atomic layer deposition
Despite the considerably improved efficiency of inorganic–organic metal hybrid perovskite solar cells (PSCs), electron transport is still a challenging issue. In this paper, we report the use of ZnO nanorods prepared by hydrothermal self-assembly as the electron transport layer in perovskite solar cells. The efficiency of the perovskite solar cells is significantly enhanced by passivating the interfacial defects via atomic layer deposition of Al2O3 monolayers on the ZnO nanorods. By employing the Al2O3 monolayers, the average power conversion efficiency of methylammonium lead iodide PSCs was increased from 10.33% to 15.06%, and the highest efficiency obtained was 16.08%. We suggest that the passivation of defects using the atomic layer deposition of monolayers might provide a new pathway for the improvement of all types of PSCs.
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