Non-directed highly para-selective C-H functionalization of TIPS-protected phenols promoted by a proton shuttle

Palladium-catalyzed non-directed C-H functionalization provides an efficient approach for direct functionalization of arenes, but it usually suffers from poor site selectivity, limiting its wide application. Herein, it is reported for the first time that the proton shuttle of 3,5-dimethyladamantane-1-carboxylic acid (1-DMAdCO2H) can affect the site selectivity during the C-H activation step in palladium-catalyzed non-directed C-H functionalization, leading to highly para-selective C-H olefination of TIPS-protected phenols. This transformation displayed good generality in realizing various other para-selective C-H functionalization reactions such as hydroxylation, halogenation, and allylation reactions. A wide variety of phenol derivatives including bioactive molecules of triclosan, thymol, and propofol, were compatible substrates, leading to the corresponding para-selective products in moderate to good yields. A preliminary mechanism study revealed that the spatial repulsion factor between proton shuttle and bulky protecting group resulted in the selective C-H activation at the less sterically hindered para-position. This new model non-directed para-selective C-H functionalization can provide a straightforward route for remote site-selective C-H activations.

Critical Factors Causing Material Wastes in Building Construction Projects

Construction sites generate a large amount of material wastes and have become a common problem with associated risks in Ethiopia. However, the sources of such wastes are not well recognised. Therefore, the purpose of this research was to analyse the risk factors that contribute to material wastes in building construction projects. To achieve this goal, the factors that cause construction wastes were identified from literature and construction experts via focus group discussions and personal interviews. Following this, the factors were subjected to a questionnaire survey to identify the most critical factors of construction wastes. The questionnaire was distributed purposively to 85 construction experts representing contractors, consultants, and clients and 70 questionnaires were duly received for analysis. The data were analysed with a mean score and ranked to identify the most critical factors generating material wastes at construction sites. According to the results of the study frequent changes made to the design, poor strategies for waste minimisation, improper storage of material, poor site management, poor planning and supervision, and errors of contract document were the most critical factors causing construction wastes.

Waterproofing of primary lining in tunnel using nano chemicals and soil modifiers in Concrete

The use of waterproofing chemicals in the field of concrete technology has proven a significant boom in the civil engineering industry by increasing the life of concrete structures. The materials such as nano-acrylic polymers resulted, significant control over the water leakage and damping conditions especially Terrasil and Zycobond and various nano sealers such as Zycoprime+ and Zycosil+. In this study, the primary focus is to waterproof tunnels using the various acrylic, nano-technological, and soil modifier chemicals to stabilize the tunnel structure in areas of hilly terrain. The use of these chemicals has been sourced in other areas of application but the least glance is seen in the field of tunnel engineering. These chemicals bind with the concrete and form a hydrophobic layer thus decreasing the permeability of concrete structure. In the present study the percentage of Zycobond and Terrasil used was 1.5% by weight of concrete and the ratio for Zs+:Zp+:water was 1:2:20. Tunnels especially in hilly terrain pass the flowing streams, thus making it more prone to damping conditions. So, poor site conditions result in less durability of concrete as well as steel, therefore improvement in engineering properties using these chemicals is primarily sought out in this paper. The factors considered during the use were the permeability, strength, volumetric analysis of chemicals, material properties etc. Water-proofing the concrete improves various engineering properties such as permeability, compressive strength, durability, strength, and various other properties of Concrete. The study emphasized to gauge the viability of Zycosil+ and Zycoprime+, Terrasil and Zycobond as waterproofing agents in concrete.

Accessibility of Vaccination Centers in COVID-19 Outbreak Control: A GIS-Based Multi-Criteria Decision Making Approach

The most important protective measure in the pandemic process is a vaccine. The logistics and administration of the vaccine are as important as its production. The increasing diffusion of electronic devices containing geo-referenced information generates a large production of spatial data that are essential for risk management and impact mitigation, especially in the case of disasters and pandemics. Given that vaccines will be administered to the majority of people, it is inevitable to establish vaccination centres outside hospitals. Site selection of vaccination centres is a major challenge for the health sector in metropolitan cities due to the dense population and high number of daily cases. A poor site selection process can cause many problems for the health sector, workforce, health workers, and patients. To overcome this, a three-step solution approach is proposed: (i) determining eight criteria using from the experience of the advisory committee, (ii) calculating criterion weights using Analytic Hierarchy Process (AHP), and performing spatial analysis of criteria using Geographic Information System (GIS), (iii) assigning potential vaccination centres by obtaining a suitability map and determining service areas. A case study is performed for Bağcılar, Istanbul district, using the proposed methodology. The results show that the suitable areas are grouped in three different areas of the district. The proposed methodology provides an opportunity to execute a scientific and strategic vaccination programme and to create a map of suitable vaccination centres for the countries.

Mosses are Important for Soil Carbon Sequestration in Forested Peatlands

Nutrient-rich peat soils have previously been demonstrated to lose carbon despite higher photosynthesis and litter production compared to nutrient-poor soils, where instead carbon accumulates. To understand this phenomenon, we used a process-oriented model (CoupModel) calibrated on data from two closely located drained peat soil sites in boreal forests in Finland, Kalevansuo and Lettosuo, with different soil C/N ratios. Uncertainty-based calibrations were made using eddy-covariance data (hourly values of net ecosystem exchange) and tree growth data. The model design used two forest scenarios on drained peat soil, one nutrient-poor with dense moss cover and another with lower soil C/N ratio with sparse moss cover. Three vegetation layers were assumed: conifer trees, other vascular plants, and a bottom layer with mosses. Adding a moss layer was a new approach, because moss has a modified physiology compared to vascular plants. The soil was described by three separate soil organic carbon (SOC) pools consisting of vascular plants and moss litter origin and decomposed organic matter. Over 10 years, the model demonstrated a similar photosynthesis rate for the two scenarios, 903 and 1,034 g C m−2 yr−1, for the poor and rich site respectively, despite the different vegetation distribution. For the nutrient-rich scenario more of the photosynthesis produce accumulated as plant biomass due to more trees, while the poor site had abundant moss biomass which did not increase living aboveground biomass to the same degree. Instead, the poor site showed higher litter inputs, which compared with litter from vascular plants had low turnover rates. The model calibration showed that decomposition rate coefficients for the three SOC pools were similar for the two scenarios, but the high quantity of moss litter input with low decomposability for the nutrient poor scenario explained the major difference in the soil carbon balance. Vascular plant litter declined with time, while SOC pools originating from mosses accumulated with time. Large differences between the scenarios were obtained during dry spells where soil heterotrophic respiration doubled for the nutrient-rich scenario, where vascular plants dominated, owing to a larger water depletion by roots. Where moss vegetation dominated, the heterotrophic respiration increased by only 50% during this dry period. We suggest moss vegetation is key for carbon accumulation in the poor soil, adding large litter quantities with a resistant quality and less water depletion than vascular plants during dry conditions.

Evaluation of the Detection Ability of New Infrasound Networks Installed by Korea Meteorological Administration

The Korea Meteorological Administration (KMA) installed infrasound networks in Cheorwon and Yanggu. These networks have been operated for detecting infrasound generated from artificial explosions, such as those due to North Korea's nuclear tests, and from natural phenomena such as the volcanic eruption of Mt. Baekdu. Currently, the KMA is simultaneously performing infrasound analysis and seismic wave analysis to discriminate between natural and artificial earthquakes. To efficiently perform the discrimination and analysis of artificial earthquakes, three infrasound networks were expanded in the West Sea and northern Gyeonggi-do Gyodong-do, Paju, and Yeoncheon. In this study, 22 cases of artificial earthquake events that occurred in North Korea in January 2020 were analyzed to test the analysis capabilities of the three newly installed infrasound networks. The results of the analysis confirmed that the newly installed infrasound networks exhibited a higher infrasound detection rate than the existing Cheorwon and Yanggu infrasound networks. The Cheorwon and Yanggu observation networks are being planned for relocation and installation due to aging and poor site conditions. The use of the new infrasound network is expected to improve the detection rate and analysis accuracy with respect to artificial earthquakes. Furthermore, it is expected to enhance the detection capability of infrasound generated from various physical phenomena such as nuclear tests performed by North Korea and volcanic eruption of Mt. Baekdu.

Claim study of contractors in Commercial Berth Project in Duqm Port in Oman

The claim during the implementation of projects is very important for the contractor and the consultant. As for the owner, it is considered expensive and cumbersome,and therefore the project contract must be very clear so that there are no gaps or defects against the owner.The aim of this research is to analyze and study deeply contractor's claim.The objectives of this study are to study the main factors for the contractor's claim to the commercial pier project in the Sultanate of Oman,including eleven factors. The second objective is to study the impact of the contractor's claim on the commercial pier project in the Sultanate of Oman, and it includes five factors, as the questionnaire was distributed to customers and various segments of society.The results of analyzing 16 factors to identify the key factors and the impact of the study of the contractors claim conclude that the main factors affecting the contactor's claim to the pier project.The factors and impacts are valid to the study after conducting analysis on the obtained data. The factors include the development unexpected weather conditions, inconsideration of the time frame, government approval of delays,poor coordination with the project parties, poor site management and supervision,a change in the clients requirements, the lack of experienced staff, incompetence among teams, low items in the bill of products,and misunderstanding the scope of work and specifications.The impacts to the completion of the Berth project include payment delays, delays in the extension of time,issuing variation order,value implementation engineering and cost reduction,and contractor's performance.

Phosphorus Availability Alters the Effect of Tree Girdling on the Diversity of Phosphorus Solubilizing Soil Bacterial Communities in Temperate Beech Forests

Phosphorus (P) solubilization is an important process for P acquisition by plants and soil microbes in most temperate forests. The abundance of inorganic P solubilizing bacteria (PSB) is affected by the P concentration in the soil and the carbon input by plants. We used a girdling approach to investigate the interplay of root-derived C and initial P content on the community composition of gcd-harboring bacteria as an example of PSB, which produce gluconic acid. We hypothesized that gcd-harboring PSB communities from P-poor sites are more vulnerable to girdling, because of their lower diversity, and that a shift in gcd-harboring PSB communities by girdling is caused by a response of few, mostly oligotrophic, taxa. We used a high-throughput metabarcoding approach targeting the gcd gene, which codes for the quinoprotein glucose dehydrogenase, an enzyme involved in the solubilization of inorganic P. We compared the diversity of gcd-harboring PSB in the mineral topsoil from two temperate beech forests with contrasting P stocks, where girdling was applied and compared our data to the respective control plots with untreated young beech trees. At both sites, gcd-harboring PSB were dominated by Proteobacteria and Acidobacteria, however, with differences in relative abundance pattern on the higher phylogenetic levels. The P-poor site was characterized by a high relative abundance of Kaistia, whereas at the P-rich site, Dongia dominated the gcd-harboring bacterial communities. Girdling induced an increase in the relative abundance of Kaistia at the P-poor site, whereas other bacterial groups of the family Rhizobiaceae were reduced. At the P-rich site, major microbial responders differed between treatments and mostly Bradyrhizobium and Burkholderia were positively affected by girdling in contrast to uncultured Acidobacteria, where reduced relative abundance was found. Overall, these effects were consistent at different time points analyzed after the introduction of girdling. Our data demonstrate that plant-derived carbon influences community structure of gcd-harboring bacteria in temperate beech forest soils.

Causes and Impacts of Conflicts in Construction Projects: A Viewpoint of Kenya Construction Industry

Construction projects are predisposed to conflicts. This is attributed to the multiplicity of personnel handling the various phases of the projects. Empirical evidence from previous studies shows that if not properly managed, conflicts affect among others, the project's productivity loss, inadequate time and cost performance levels, loss of profit, and damage in business relations. Identifying the significant causes and major potential impacts of conflicts is crucial to reducing the risk of conflict occurrence in projects. Hence, this study was focused on explaining the classification of conflicts, identifying and assessing their causes and impacts in construction projects in Kenya grounded on the perception of project consultants and contractors. To accomplish the study objectives, a questionnaire was designed to collect data on the experiences of construction professionals on the causes and impacts of conflicts during project implementation. A total of 122 consultants and contractors provided responses, which were analyzed. A total of 42 significant causes of conflicts in the Kenyan context were identified. Based on the survey results, delay in progress payments by the client was identified as the most significant cause of conflicts, followed by poor site management and supervision. The survey also revealed that conflicts can emerge from any of the stakeholders, with contractors contributing the most, accounting for 14 of the 42 conflict factors identified. The study ranked the impacts of these conflicts using the Relative Severity Index (RSI). The results indicated that the biggest impact of conflicts on construction projects is the loss of profitability and perhaps business viability, and delays in project delivery. Expert opinions regarding the best practices and strategies for improving project harmony through effective conflict management were reviewed and grouped into five classes namely; project documentation, stakeholder involvement, value-based procurement, and adoption of ICT. It is concluded that the project manager should develop his leadership role by the adoption of these strategies so that he can use his position to effect positive conflict management on his team members. Furthermore, during the life cycle of the construction project, special attention should be given to the identified cause factors to avoid or effectively manage conflicts. These results, taken together, support clear guidelines on the need for proactive financial obligation on the client-side, as well as the hiring of experienced project professionals. Implementing these suggestions would reduce the risk of conflicts arising during building projects.

Evaluation of GIS based Ranking and AHP methods in selecting the most suitable site: A case study in Kayseri, Turkey

Demand for renewable energy sources is increasing since traditional energy sources (i.e., coal, oil, and natural gas) have limited reserves and cause high greenhouse gas emission. Suitable site selection for new generation renewable resources is vital in large-scale projects. In this paper, suitable sites for solar photovoltaic (PV) power plants were selected for a Kayseri, Turkey case. Geographic information systems and multi criteria decision-making (MCDM) methods were integrated to exploit and construct the best location for solar PV power plants. In this context, three main, twelve sub-criteria, and their indicators were determined by considering expert opinion and previous studies. The rank based (i.e., rank sum, rank reciprocal weights, and rank order centroid weights) and analytical hierarchical process (AHP) methods were used to determine the weights of the criteria. The suitability maps created according to the calculated weights were divided into 5 levels (i.e., excellent, good, fair, low, poor site). To compare the success of MCDM methods, 33 existing installed PV power plants were randomly selected and used for validation. It was determined that the rank reciprocal method was the most successful in selection of the most suitable site. Four MCDM methods determined that the Sarız, Tomarza, and Incesu districts of Kayseri were the most suitable sites.