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Nickel and its compounds are widely used in industrial and manufacturing processes. NiCl2 and Ni(NO2)2 are two common soluble salts of nickel, and both are toxic to living organisms. In this study, we examined and compared the cytotoxic effects of NiCl2 and Ni(NO2)2 on the HEK293T cell line by evaluating cell viability and determining the half-maximal inhibitory concentration (IC50) for each compound. The results of our study indicate that both NiCl2 and Ni(NO2)2 are cytotoxic to the HEK293T cell line in a dose-dependent manner, and the (IC50 = 60.484 μg/ml) for nickel chloride and (IC50 =55.652 μg/ml) for nickel nitrate. Nickel nitrate was slightly more toxic than nickel chloride. Increased cytotoxicity of Ni(NO2)2 and NiCl2 should be considered in the assessment of the toxicity of nickel compounds on other cell lines in future studies.

Silver nanoparticles (Ag-NPs) with antimicrobial activity are by far the most commercialized nano-compound. However, there is limited information about antitumor potential. Therefore, the present study was aimed to observe the effect of small-dimensional Ag-NPs (20Nm) on human epithelial colorectal adeno-carcinoma (Caco-2) cells. Caco-2 cells were exposed to Ag-NPs with different concentrations (1–15μg/mL) for 24 and 48 hours and cytotoxicity was analyzed by MTT assay and IC50 was calculated. In addition, flow cytometry was used to determine the effect of Ag-NPs on the cell cycle progression and on apoptosis. An MTT assay revealed that following exposure to Ag-NPs the viability of Caco-2 cells decreased, and the viability decreased further with increasing exposure time. The IC50 was 7.85 µg/ml and 4.92 µg/ml at 24 and 48 h respectively after exposure. The flow cytometry technique revealed that Ag-NPs induced a significant increase in the percentage of cells in G1 phase of the cell cycle and of apoptotic cells. In conclusion, Ag-NPs exhibited dose- and time-dependent cytotoxicity, and these results have signposted that Ag-NPs were promising nanoparticles which could be a potential candidate in treating colorectal cancer.

To ensure quick socio-economic recovery of the communitiesaffected by insurgents’ attacks in the north-eastern Nigeria, the first phase of the mass-housing reconstruction scheme has been completed but with many issues overshadowing the achievement like unsatisfactory involvement of local beneficiary communities;poor cooperation among key stakeholders; and communication gaps between donors, construction companies and local beneficiaries, which results inlow quality housing products. Therefore, it became necessary to ensure that only contractors who satisfactorily passed the efficiency test are allowed to participate in the subsequent phases of the reconstruction scheme. Thus, this paper provides quantitative technique for evaluating the efficiency of contractors in managing the housing reconstruction.It is expected that the techniquewill seek to guide informed decisions on the efficiency of managing the reconstruction scheme, which is in different phases and locations. Although the evidences on which the results of this study emanate from reconstruction of building structures experiences in some parts of Nigeria, the technique developedcould be adopted in other areas faced with similar issues.This paper updated existing knowledgeon the management of mass-housing reconstructionworks and offers support to decision-makers and practitioners involved in managing reconstruction of building structures affected by insurgency

Selecting a suitable bidder to execute a construction project is not an easy task, especially for the short bidder list. The consequences of the selection might affect the project performance in terms of cost, money, and quality. The current research in this work deals with the selection of a contractor, who bids on a specific project. The historical data of contractors are a key of the selection based on three approaches: the quick selection approach (QSA), generic selection approach (GSA), and comprehensive selection approach (CSA). The QSA relies on the scoring system according to delay factors. The QSA is the weighted average of the delay factors using the analytical hierarchy process (AHP), the CSA is based on the integrated QSA and the bidding strategy using Friedman’s theory. The current three approaches can be utilized by public and private owners, who intend to select a general contractor to execute new construction projects. A hypothetical case study is implemented to demonstrate the developed models. Several experts in the field of construction management have confirmed the findings. The third strategy (CSA) is found to be the most appropriate for selecting construction bidders.

Worker productivity is critical within construction projects as it is the measure of the rate at which work is performed and, more importantly, helps to know how to motivate them to perform at high levels. This research aimed to examine the impact of employee age and industry experience on the intrinsic workforce diversity factors influencing construction worker productivity. Sieving through the previous research and models and theories of analysis, the intrinsic workforce diversity was modeled into the following set of factors, i.e., income, motivation, psychosocial factors, and technical skills. The data were collected by means of a questionnaire survey and examined for the employees having different ages and experiences using the Mann–Whitney U test through SPSS. The results show that employees of varied ages do not concur over motivation-, psychosocial, and technical skills-related workforce diversity factors, whereas employees of varied industrial experiences are in disagreement over some income and motivation related workforce diversity factors. In order to overcome intrinsic workforce diversity, firm support is direly needed for old and mature employees in terms of financial incentives leading to motivation, less supervised scheduling, opportunities for firm advancement, and reporting back every time work is completed. Furthermore, support is required for young employees who are more susceptible due to psychosocial stresses like unevenly distributed work, communication gaps, and technical skills like knowledge of technological equipment and advancement in construction technology which has reduced the skills of workers.

Municipalities in Canada have noted that 59% of their water systems need repair, and the condition of 43% of those systems is apparently intolerable. Hence, large volumes of rehabilitation projects are necessary to improve the performance of Canadian water systems. A reliability (R) and criticality index (CI) are crucial for prioritizing rehabilitation activities and distribute budgets efficiently. “R”is a function of failure rate, while“CI”is a function of economic, operational, social, and environmental factors. The research presented in this paper aimed to develop a performance index (PI) that considered the combination of “R” and “CI” for water networks. Sound techniques were utilized to generate the PImathematical model, such as reliability theory, simple multi-attribute rating technique (SMART), and Analytical Hierarchy Process (AHP). Data on water networks were collected from the city of Hamilton, Ontario, Canada. Four sub-networks were selected from the entire network to represent four types of land uses; undeveloped, residential, park, and commercial/industrial. The results showed that the PI value was 0.72, 0.93, 0.87, and 0.76 for these types of land uses, respectively. The developed models and tools are assumed to be beneficial for municipal engineers and managers as well as academics.

The main objective of this paper is to study feasibility of using ultra-lightweight (ULW) slab as an alternative design solution for floor component used in high-rise buildings. The main method is numerical case study by comparing the structural performances of 60-storey building in which floor component designed using one type of ULW called cross laminated timber (CLT) relative to floor component designed using conventional reinforced concrete (RC) slab using ETABS. The structural performances were compared between the two types of floor system including: total drift, inter-story drift, and base reaction which results in smaller frame sections and less reactions for the foundation demands by using ultra-lightweight (ULW). Additional study in term of survey to assess the awareness level of the public and engineering professionals about general high-rise building demand and new alternative building materials such as timber and its potential application in Saudi Arabia was also conducted.

The use of reindeer resources in Central Siberia - the main welfare source for the majority of farms and the indigenous population of the North region. Protection and rational use of Taimyr-Evenk reindeer population inhabiting the Krasnoyarsk territory on the area of more than 1.5 million km2 are impossible without the use of modern remote sensing methods. It provides objective and live data information about the spatial and temporal location of animals at different stages of their life cycle. Monitoring carried out with the use of modern technical devices allows to solve not only applied control problems, but also to obtain new unique knowledge about the biology of this species. The basis for this message was the materials on the use of collars equipped with satellite transmitters of the Argos system and worn on deer. A total number of collars was 17, which were worn on reindeer in their wintering grounds, except for one, which a half-grown female was marked during the crossing of the Heta river. From a technical point of view, it was important to trace the total duration of the beacon and the viability of the battery packs in extreme temperature amplitude and also to establish reliability of the device protection from physical and mechanical influence during migrations of animals. The maximum duration of signal receipt with using the new battery packs in 2015-2016 amounted to 438 and 444 days, in 2017-2018 – 539 days. The maximum length of the deer during the satellite direction finding was 9538 km. The average speed was 13.5 km / day; the maximum was up to 45-72 km / day in azimuth. Used collars with radio beacons of Argos satellite system produced by ES-PAS Ltd. (Russia), showed a high degree of functional reliability.

Scheduling of the rehabilitation activities of water main networks depends mainly on available budget and planning time. Other factors such as network reliability, criticality, location, contract size, and rehabilitation method(s) affect the optimization of the scheduling process. This paper presents a method for optimized scheduling of rehabilitation work for water distribution networks. The method utilizes unsupervised neural networks (UNNs) and mixed-integer nonlinear programming (MINLP) and performs the scheduling in two stages. In the first stage, UNNs are used to cluster water mains into groups according to locations and rehabilitation methods of water mains. In the second stage, MINLP is used to determine the number of rehabilitation contract packages and the generation of optimized scheduling of these packages considering network reliability, criticality, contract size, and planning time. In order to demonstrate the essential features of the developed method, a case study was analyzed and ...

Canadian municipalities have noted that 59% of their water systems and 68% of their sewer systems required repair. To rehabilitate, replace or construct a water or sewer pipeline, several methods can be used: open-cut or one of several trenchless technologies (TTs). The selection of the method positively affects the surrounding environment. Therefore, the impact on environment (IoE) becomes a vital concern in selecting the appropriate construction or rehabilitation method for water or sewer pipelines. The research presented in this paper aims at developing an IoE model that compares the open-cut and TT methods. The IoE factors and their related data are collected, analysed and categorised based on literature review and expert opinion. Two models are designed in order to assess the IoE of the open-cut and TT methods. Results of the open-cut technique show that the impact on social factor has the maximum relative weight of 0.36; however, the impact on project characteristics has 0.33 and on environment has ...

In view of the importance and demanding roles of steel rebar's in the reinforced concrete structures, accurate information on the properties of the steels is important at the design stage. In the steelmaking process, production variations in chemical composition are unavoidable. The aim of this work is to study the variability of the chemical composition of reinforcing steel produced throughout the Saudi Arabia and asses the quality of steel rebar's acoording to ASTM A615. 68 samples of ASTM A615 Grade 60 from different manufacturers were collected and tested using the Spectrometer test to obtain Chemical Compositions. EasyFit (5.6) software is utilized to conducted statistical analysis. Chemical compositions distributions and, control charts are generated for the compositions. Results showed that some compositions are above the upper line of the control chart. Finally, the analyses show that less than 3% of the steel failed to meet minimum ASTM standards for chemical composition.

The popularity of mobile devices and the enormous number of third party mobile applications in the market have naturally lead to several vulnerabilities being identified and abused. This is coupled with the immaturity of intrusion detection system (IDS) technology targeting mobile devices. In this paper we propose a modular host-based IDS framework for mobile devices that uses behavior analysis to profile applications on the Android platform. Anomaly detection can then be used to categorize malicious behavior and alert users. The proposed system accommodates different detection algorithms, and is being tested at a major telecom operator in North America. This paper highlights the architecture, findings, and lessons learned.

City managers and elected officials in many municipalities are frequently faced with the challenge to cater for public expectations on one hand and to comply with technical/engineering requirements on the other. This paper presents a four phased level of service driven reliability based methodology for allocation of budget to water mains. This methodology comprises of: (1) development of an Analytical Hierarchy model of LoS; (2) a sub-network criticality model to account for certain quantitative and qualitative characteristics of a given sub-network (3) a sub-network reliability assessment model and 4) a budget allocation model. Combination of the above contradicting requirements, i.e. level of service and network reliability, is expected to assist decision makers in quantifying the required condition improvement to meet service goals and to make more informed decisions on interventions and relayed priorities. To show the robustness of the developed models, a hypothetical case study is developed and analyzed.

Selecting most suitable methods for rehabilitation of water main networks has become a challenging task; considering the wide range of emerging trenchless methods. Developing decision support methods is expected to assist municipalities in North America and elsewhere in carrying out the selection process effectively. This paper introduces a new concept for choosing cost effective rehabilitation methods accounting for cost and duration of each rehabilitation method being considered along with its impact on environment using Multi-Objective evaluation methodology (MOM). The first objective, cost of rehabilitation, is calculated considering a number of cost elements including social cost. Social cost, in the developed methodology accounts for cleaning costs, loss of sales tax, number of impacted vehicles and pedestrians, etc. The second objective is the duration of the rehabilitation method under consideration. The environmental impact is considered as the third objective. It is modeled considering several factors using the Analytical Hierarchy Process (AHP). In order to demonstrate the essential features, a hypothetical example has been developed to test the model robustness. Results show that a cost effective method can be selected by combining cost, duration, and impact on environment.