pH-Dependence and Contributions of The Carbonic Species To Co2 Flux Across The Gas/Liquid Interface

The purpose of this article is to expand the available knowledge on CO2 transfer across the gas/liquid interface in two ways: (1) propose a new mathematical model to describe the pH dependence of CO2 flux across the gas/liquid interface; and (2) propose new relationships that quantitatively describe the contributions of each of the carbonate species ( 2 3 H CO , − 3 HCO , and 2− 3 CO ) to total flux across the gas/liquid interface. The new model was based on accounting for the difference between the pH in the liquid phase at any time during gas transfer and the pH of the liquid phase at equilibrium when net gas transfer stops. The article also proposes a correction to the currently in-use mathematical model, which was found to apply in the special change and in unlikely cases in which the initial pH does not change. The theoretical and experimental work presented in this article present clear theoretical and mathematical understanding of the process of gas transfer involving acidbase ionization reactions. Numerous batch and continuous-flow countercurrent reactors CO2 stripping experiments were conducted at different initial pH values to verify the proposed model. The experiments included runs in which the pH was allowed to change as a result of CO2 transfer and experiments involving buffered solutions in which the pH did not change significantly. In all cases, the experimental results matched the theory in an excellent manner

Assessment of Seasonal and Annual Rainfall Trends and Variability in Sharjah City, UAE

Although a few studies on rainfall spatial and temporal variability in the UAE have been carried out, evidence of the impact of climate change on rainfall trends has not been reported. This study aims at assessing the significance of long-term rainfall trends and temporal variability at Sharjah City, UAE. Annual rainfall and seasonal rainfall extending over a period of 81 years (1934–2014) recorded at Sharjah International Airport have been analyzed. To this end, several parametric and nonparametric statistical measures have been applied following systematic data quality assessment. The analyses revealed that the annual rainfall trend decreased from −3 mm to −9.4 mm per decade over the study periods. The decreasing annual rainfall trend is mainly driven by the significant drop in winter rainfall, particularly during the period from 1977 to 2014. The results also indicate that high probability extreme events have shifted toward low frequency (12.7 years) with significant variations in monthly rainfall patterns and periodicity. The findings of the present study suggest reevaluating the derivation of design rainfall for infrastructure of Sharjah City and urge developing an integrated framework for its water resources planning and risk under climate change impacts scenarios

A Comparative Earthquakes Risk Assessment Approach Applied to the United Arab Emirates

This paper presents the preliminary results of a long research project on the assessment and mitigation of seismic risk in major cities in the UAE. UAE’s earthquake activity has long been recognized as one of the lowest in the world. All cities have experienced moderate earthquakes in the past, and will again do in the future. Recent earthquakes in Iran (e.g., Bam in 2003, --- in 2005) have killed thousands of people. Because of the different design and construction practices, different population density concentrations and economic activities in the UAE, different damages and losses are likely to be experienced. The impact of an earthquake is not limited to direct losses, such as the loss of life, loss of structures and business interruptions. Earthquakes also cause indirect losses by producing supply shortages and demand reductions in various economic sectors. In a country such as the UAE, which is undergoing an unprecedented constructionbased development with high-rise buildings being the main feature, a large earthquake in a major city can actually cause a considerable economic loss. In this study, a framework for assessing and comparing the risk associated with the adverse consequences of earthquakes in the UAE is presented. The framework is based on a simple risk-characterization model that is used to assess the health risks associated with toxic chemicals. The model: Risk = D × RF × Pop × ER, adopted to fit our purpose of estimating the risk associated with the consequences of earthquakes, the various parameters in the above mentioned model are translated as follows: Dose (D)= seismic “force” at a specific location or weighted for an area; Response Factor (RF) = degree of damage or losses per unit “force”; Population (Pop) = a factor representing exposed population. Equivalent populations may also include exposed environment or exposed infrastructure. Emergency Response (ER) = effectiveness of available emergency response programs to reduce risk immediately as the adverse effects take place. It should be noted that emergency response in this case is different than deliberate risk management. First, the earthquake hazard and risk in the UAE, including the estimation of the amplitudes of the ground motion parameters, is stochastically assessed. Then the comparative risk framework to assess the relative impacts on people and buildings in the seven emirates and the major cities of the UAE is applied. The result is a ranking system for risk that is being integrated within a geographic information system (GIS). The database is intended for detailed development to maximize benefits to the various stake holders in the community

Optimization of biodiesel production from waste cooking oil using a green catalyst prepared from glass waste and animal bones.

Biodiesel as a fuel has been shown to positively impact the environment; replacing or reducing the dependence on fossil fuels while providing a viable alternative. The use of waste oils, such as non-edible or used oils, can reduce competition with food, loss of resources, and the resulting higher prices. In this study, biodiesel was obtained by a transesterification reaction using used cooking oil from fast-food restaurants as the feedstock and catalysts from waste glass and animal bones as the silica and calcium oxide sources, respectively. Utilizing waste or non-edible oils for the production of biodiesel can lessen the competition with food sources while achieving environmental and ethical biofuel standards. Additionally, employing readily available waste oils and catalysts prepared from waste material is an economical and low-cost process compared to the use of conventional expensive feedstock and catalyst. The catalyst characterization for the prepared CaO–SiO2 catalyst was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). The reaction was optimized using the response surface methodology (RSM) with central composite design (CCD) by varying three parameters: methanol-to-oil ratio, catalyst weight fraction (wt%), and reaction time. The highest biodiesel yield obtained using Design Expert software was 92.3419% at the optimum conditions of a 14.83:1 methanol-to-oil molar ratio, 3.11 wt% catalyst, and 143 min reaction time. This proved that waste cooking oil with CaO–SiO2 catalyst could be used in the transesterification process to produce a high yield of biodiesel, which was shown in the results obtained from the experimental runs

Co-pyrolysis for bio-oil production via fixed bed reactor using date seeds and plastic waste as biomass.

The consumption of plastic bottles is relatively high in the United Arab Emirates (UAE). Therefore, in this study authors investigated the potential of combined plastic waste and locally available biomass (date seeds) to produce value-added products (bio-oil, bio-char and syngas) via pyrolysis process. The experiments were performed in a fixed bed pyrolizer, operated at different temperatures. Experimental results showed that 500 °C would be a better option for a higher bio-oil yield (59.16%), while lower temperatures (300 °C) produced more bio-char yields (24.97%). A plastic ratio of 70% gives the highest bio-oil content (62.57%), and lowest amounts of bio-char (12.14%). Experiment performed at 400 °C with a plastic waste ratio of 30% have the highest bio-oil density (1.020 g/cm3). The results obtained in this study showed that the co-pyrolysis of plastic waste and date seeds are suitable for bio-oil production as sustainable biofuel in UAE

Deep learning detection of types of water-bodies using optical variables and ensembling

Water features are one of the most crucial environmental elements for strengthening climate-change adaptation. Remote sensing (RS) technologies driven by artificial intelligence (AI) have emerged as one of the most sought-after approaches for automating water information extraction and indeed. In this paper, a stacked ensemble model approach is proposed on AquaSat dataset (more than 500,000 images collection via satellite and Google Earth Engine). A one-way Analysis of variance (ANOVA) test and the Kruskal Wallis test are conducted for various optical-based variables at 99% significance level to understand how these vary for different water bodies. An oversampling is done on the training data using Synthetic Minority Oversampling Technique (SMOTE) to solve the problem of class imbalance while the model is tested on an imbalanced data, replicating the real-life situation. To enhance state-of-the-art, the pros of standalone machine learning classifiers and neural networks have been utilized. The stacked model obtained 100% accuracy on the testing data when using the decision tree classifier as the meta model. This study has been cross validated five-fold and will help researchers working in in-situ water bodies detection with the use of stacked model classification

Anticancer activities of selected Emirati Date (Phoenix dactylifera L.) varieties pits in human triple negative breast cancer MDA-MB-231 cells

The date palm (Phoenix dactylifera L.) is an important fruit crop with significant pharmaceutical potential. Little data are available on comparative pharmaceutical importance of the date pits. We designed this study to assess the antitumorigenic effects of date palm pits extracts from different Emiratis varieties. We used MDA-MB-231 cells derived from triple negative breasts cancer tissues as a model. We found that out of the 17 date pits extracts from 6 Emiratis varieties, three (Khalas extract in water + acetone (1:1), Abu-Maan extract in MeOH + Chloroform (1:1) and Mabroom extract in water + acetone (1:1)) were found effectively cytotoxic and changed morphology of cells in dose and time dependent manner. We found the maximum effect at 2.5 mg/mL concentration at 72 h. We calculated IC50 values for these varieties at 24 h. IC50 values for Khalas, Abu-Maan and Mabroom were 0.982 mg/mL, 1.149 mg/mL and 2.213 mg/mL respectively. We treated the cells with IC50 values of extracts and observed changes in protein profile using human kinase array kit. After analyzing the results, we suggest that EGFR/ERK/FAK pathway, eNOS and src family proteins are targets of these extracts. We conclude that date pits extracts can be a possible therapeutic agent against cancer and we suggest further studies

Life cycle cost analysis of a sustainable solar water distillation technique

This paper presents a detailed estimation of the fabrication cost, water production cost (WC), and cost payback period (CPP) using annualized life cycle costing for a tubular solar still (TSS). The operation and maintenance cost (OM) and the number of sunny days in a year (d) have a significant effect on the WC. The WC is raised from 3.1 to 4.4¥/L, if the OM increases from 5 to 18% of the capital cost, respectively. The WC is dropped by 35% (in average) when the d increases from 230 to 350 days. In addition, the CPP is greatly affected by the water selling prices and d. The CPP is dropped from 68 to 45 days due to the increase of d from 230 to 350 days (in average), respectively. The fabrication cost of the TSS ($5) and the WC ($31/m3) are affordable and much lower than the single-sloped passive solar still. Finally, it is revealed that the solar radiation is the most influential parameter on the productivity of TSS and a linear proportional relationship is found between them

COVID-19 Lockdown and the Impact on Mobility, Air Quality, and Utility Consumption: A Case Study from Sharjah, United Arab Emirates

This study presents an analysis of the impact of COVID-19 lockdown on people’s mobility trends, air quality, and utility consumption in Sharjah, United Arab Emirates (UAE). Records of lockdown and subsequent easing measures, infection and vaccination rates, community mobility reports, remotely sensed and ground-based air quality data, and utility (electricity, water, and gas) consumption data were collected and analyzed in the study. The mobility trends reflected the stringency of the lockdown measures, increasing in the residential sector but decreasing in all other sectors. The data showed significant improvement in air quality corresponding to the lockdown measures in 2020 followed by gradual deterioration as the lockdown measures were eased. Electricity and water consumption increased in the residential sector during the lockdown; however, overall utility consumption did not show significant changes. The changes in mobility were correlated with the relevant air quality parameters, such as NO2, which in turn was highly correlated to O3. The study provides data and analysis to support future planning and response efforts in Sharjah. Furthermore, the methodology used in the study can be applied to assess the impacts of COVID-19 or similar events on people’s mobility, air quality and utility consumption at other geographical locations

Potential Factors That Trigger the Suspension of Calcium Carbonate Sediments and Whiting in a Semi-Enclosed Gulf

Whitings, the manifestation of high levels of suspended fine-grained calcium carbonate particles in the water, have been reported and studied worldwide. However, the triggering mechanism of whiting occurrences remains uncertain. The current study attempted to analyze potential factors that might account for whiting occurrences in a semi-enclosed gulf (namely the Arabian/Persian Gulf, hereinafter called the Gulf). First, spatial and temporal variability of whiting events and different potential driving factors (i.e., whiting seasonality, wind-induced mixing, sea surface temperature, and bathymetry) were explored and examined for five years (2015–2020). Second, as a general indicator of whiting occurrences in the Gulf, a whiting index (WI) was developed using time-series analysis and decision tree (DT) classification algorithm. Third, the correlation between the proposed WI and the spatial coverage of various whiting events was examined. Time-series analysis showed that whiting events during the winter season are associated with high winds that lasted for several days. Nevertheless, whiting events were rarely observed despite high wind speed and increased potential for CaCO3 precipitation in summer. This finding suggests that wind-driven forces might be potential sources for mixing water columns, resuspension of CaCO3 particles, and the appearance of whiting in the Gulf. The DT classification algorithm demonstrated that a minimum WI value of 1.1 can explain the initiation of most summer and winter whiting events. Furthermore, a Pearson correlation coefficient of 0.73 was measured between WI and the extent of whiting along the UAE and Qatar coastlines in the Gulf. The proposed WI shows a simple yet effective method for identifying and estimating the extent of whiting in the Gulf