Mechanical Performance and Thermo-Physical Properties of Cement Mortar Incorporating Hybrid Slags

Owing to the growing environmental pressure to reduce waste and pollution, the effective utilization of industrial solid wastes in construction applications has gained notable attention. This study investigates the mechanical and thermal properties of cement mortars incorporating two types of waste slags. Ferrochrome (FeCr) slag aggregate was used as a replacement for sand at the ratios of 25, 50, 75 and 100 wt. %. Ground granulated blast furnace slag (GGBS) has been used as a partial replacement of cement at the ratio of 25 wt. %. Compressive strength, permeable voids content and thermal conductivity tests have been conducted after 28 days of curing. The microstructure characteristics have been investigated by scanning electron microscope (SEM) equipped with energy dispersive analytical x-ray unit (EDAX). The experimental results revealed that FeCr waste aggregates could satisfactorily replace for natural fine sand in cement mortars up to 25 wt. % without a remarkable degradation of the compressive strength. Furthermore, Increasing replacement ratios of FeCr aggregates over 25 wt. % have resulted in noticeable decrease in thermal conductivity and an increase in the permeable voids content of cement mortars. The integration of GGBS with FeCr aggregates leads to enhanced compressive strength, reduced voids content and contribute to improved microstructure. The developed mortars with comparatively improved thermal resistance can be recommended for several structural and non-structural applications especially in hot weather regions.The authors would like to acknowledge the financial support provided by Sohar Port and Free Zone Company under Sultan Qaboos University Grant No. CR/ENG/ CAED/18/07

Identification of Possible Migration of Contaminants in Groundwater at a Landfill – A Case Study of Oman

In this study exploratory borehole drilling along with soil core sampling, chemical analysis, piezometer construction, field and laboratory hydrochemical analyses and pumping test were applied. The main aim was to understand the extent of contamination and contaminant movement in the unsaturated zone and groundwater at a dumping site in Northern part of Oman (Barka dumping site). Water samples were analyzed for inorganic, organic and biological characterization to identify any potential contamination of groundwater from Barka dumping site. Results showed elevated concentration of TDS, Na, Ca, Mg, alkalinity, chloride and total hardness. Thus, indicated that the groundwater below the dumping site is strongly affected by leachate originated from liquid lagoons located in and around the landfill. Furthermore, microbiological parameters showed that groundwater beneath Barka dumping site is largely influenced by bacterial contamination with total coliform and E.coli. Keywords: Borehole drilling; dumping site; groundwater contamination; unsaturated zone; contaminant transpor

INVESTIGATION OF NOISE EXPOSURES, PERCEPTION, AND HEALTH EFFECTS IN DIFFERENT MICROENVIRONMENTS IN A UNIVERSITY COMMUNITY

This study aims to assess noise levels in selected outdoor and indoor microenvironments in a University community in Oman. The perception of noise levels within the Sultan Qaboos University campus was investigated through a survey study. Also, the effect of exposed noise levels on annoyance and sleep disturbance were predicted including their potential risk on cardiovascular health. Among all the measured parameters, it was found that outdoor (41.6%-50%) and indoor (38.5%-46.2%) microenvironments have exceeded the critical levels of 55 dB during morning and afternoon periods. The respondents (698 people) identified traffic and indoor building-related activities as the main sources of noise levels but the majority (44%) of them rated their impact as low. However, more than 30% of the respondents considered traffic as the main contributor to University noise levels. The percentage of highly annoyed persons was predicted to be high in outdoor areas especially in the residential (25%) and near the hospital (13%) areas. However, indoor environments including construction materials and structures labs (14%) showed similar annoyance rates. Also, the percentage of high sleep disturbed persons was found higher in residential areas (7.4%) areas compared to hospital areas (5.3%) locations. The study concluded that there might be an association between the exposed noise levels and the risk of developing cardiovascular diseases. This is the first study that has provided a high spatial variability noise exposure levels across a University environment in Oman, this will contribute to designing future sustainable mitigation strategies to improve the health and well-being of the exposed population. The study has provided a baseline knowledge needed for future epidemiological studies

Bio-Oil Upgrading by Catalytic Cracking Over Different Solid Catalysts

Fossil fuel crises along with global environmental issues, due to combustion of fossil fuel, lead to focus on biomass derived fuels. Bio-oil nowadays is seriously considered to be one of the favorable, renewable and alternative energy sources to replace fossil fuel and has become a significant energy carrier for transportation, industrial and commercial applications. In this study, bio-oil was upgraded by catalytic cracking in a fixed bed reactor in the presence of three different catalysts HY, H-mordenite and HZSM-5.All of the experimental runs were carried out at 500 °C, 0.3MPa and 15:1 oil to catalyst ratio. Catalysts characterization revealed that HZSM-5 with uniform pore and TPD analysis shows the presence of large number of acidic sites as compared to HY and H-mordenite. HZSM-5 proved its effectiveness in terms of deoxygenation and converting oxygenating compounds to hydrocarbons. The amount of hydrocarbons formed was 16.27 wt % OLP for HZSM-5, 15.16 wt% for HY and 14.954 wt % for H-mordenite. HZSM-5 possessed a strong acidity, uniform pore size and high activities which tended to permit the transformation of the oxygenated compounds present in the bio-oil to hydrocarbons. The upgraded bio-oil obtained posses improved physiochemical properties such pH which was increased from 2.21 to 3.56 while density was decreased upto 0.82 kg/m3. The calorific value also increased upto 31.65 kJ/kg. The improved bio-oil by HZSM-5 catalyst can be considered as a potential for to be used as direct fuel

Baseline Measurements of Waves and Currents along the Coast of Oman

The coast of Oman is undergoing huge coastal developments in order to realize Oman Vision 2040, covering all the strategic sectors. Historical data of coastal hydrodynamic parameters is scarce, even though its importance for properly designed coastal structures is recognized. In the present study, Acoustic Doppler Current Profilers (ADCP) were deployed at eleven locations along the coast of Oman. These locations were selected based on their strategic importance for the country. The duration of the deployments were between 60 and 265 days. The measured data of the waves and currents were collected and analyzed using equipment-specific software and Excel. The significant wave heights can reach 2 m along the whole coast of Oman. The southern coast is dominated by swells. The maximum to significant wave height ratio is approximately 1.5, which is less than the value of 2 obtained using the Rayleigh distribution. The coastal currents are stronger along the southern coast than those along the northern coast. The range of current magnitude is between 0.02 m/s and 0.8 m/s. This baseline study will help the public authorities in establishing permanent hydrodynamic measurement stations along the coast of Oman. Moreover, these measurements will serve the practicing engineers in designing coastal structures along the coast of Oman

A study of beach use and perceptions of people towards better Management in Oman

1327-1333This study aimed to evaluate the quality of beaches in the Al-Suwaiq Wilayat (administrative zone) of Al-Batinah North in Sultanate of Oman to identify beach user’s priorities, concerns and preferences with regard to their beach use and visit in the area. Questionnaire survey was undertaken across 109 households using random sampling method in the Wilayat. Number of questions asked to respondents about beach use, concerns as well as perceptions of environmental quality. In general, results of survey indicated that beach users seem to satisfy with their recreational experience but there is a dissatisfaction with regard to provision of services and public would like to see improvement of beaches in the area. Besides this, there is an indication of disturbances caused to beach environment by stray animals, litter pollution and coastal erosion in some parts along the coast of Al-Suwaiq Wilayat. Therefore, actions towards beach management needs to be considered to improve the quality and increase beach users’ satisfaction. Users are concerned with environmental degradation and natural values of beaches

Optimization of a baffled-reactor microbial fuel cell using autotrophic denitrifying bio-cathode for removing nitrogen and recovering electrical energy

Microbial fuel cells (MFCs) gained emerging attention as an eco-friendly pathway for recovering electrical energy and treating wastewater. The electrochemical catalysis of cathodic reactions was one of the important issues for practical application of MFC technology. Here, it was disclosed the performance of a stake up-flow baffled-reactor MFC in which autotrophic denitrifying microorganisms catalyzed the cathodic reactions, reducing nitrate to nitrogen gas. The maximum power produced in this bio-electrochemical system (BES) was 15\ua0±\ua00.4\ua0W\ua0mNCV (net cathode volume) at an optimum cathodic nitrate loading rate (CNLR) of 150\ua0g NO −N mNCV dusing acetate as electron donor. A maximum of 76.5\ua0±\ua00.5\ua0A\ua0mNCV current and 97.7\ua0±\ua01.8% cathodic coulombic efficiency obtained at this CNLR. Autotrophic denitrification achieved on this bio-cathode was 148.3\ua0±\ua01.4\ua0g\ua0N\ua0mNCV dutilizing biological anode. The efficiency of autotrophic denitrification and current generation of this BES was inhibited by the accumulation of denitrifying by-product, nitrite (NO ), at concentrations beyond 3.59\ua0±\ua00.8\ua0mgNO −N Lin the cathodic stream. The results demonstrated that this bio-cathode based baffled-reactor MFC had a good potential to eliminate abiotic cathodes and thus, made the system more economical and sustainable alternative for wastewater treatment, nitrogen removal and energy generation