Performance of a small-scale solar-powered adsorption cooling system

In this study, an experimental investigation on the performance of a small-scale residential-size solar-driven adsorption (silica gel-water) cooling system that was constructed at Assiut University campus, Egypt is carried out. As Assiut area is considered as hot, arid climate, field tests for performance assessment of the system operation during the summer season are performed under different environmental operating conditions. The system consists of an evacuated tube with a reflective concentration parabolic surface solar-collector field with a total area of 36 m², a silica gel-water adsorption chiller of 8 kW nominal cooling capacity, and hot and cold water thermal storage tanks of 1.8 and 1.2 m³ in volume, respectively. The results of summer season field test show that under daily solar insolation varying from 21 to 27 MJ/m², the solar collectors employed in the system had high and almost constant thermal efficiency. The daily solar-collector efficiency during the period of system operation ranged from about 50% to 78%. The adsorption chiller performance shows that the chiller average daily coefficient of performance (COP) was 0.41 with the average cooling capacity of 4.4 kW when the cooling-water and chilled-water temperatures were about 31°C and 19°C, respectively. As the chiller cooling water is cooled by the cooling tower in the hot arid area, the cooling water is at a higher temperature than the design point of the chiller. Therefore, an experiment was carried out using the city water for cooling. The results show that an enhancement in the chiller COP by 40% and the chilling power by 17% has been achieved when the city water was 27.7°C.     

Incorporating green and sustainable remediation analysis in coal combustion residuals (CCR) surface impoundment closure decision making

In response to new coal combustion residuals (CCR) disposal regulations, many coal‐fired utilities have closed existing unlined surface impoundments (SIs) that were traditionally used for disposal of CCR. The two primary closure options are closure‐in‐place (CIP), which involves dewatering and capping, and closure‐by‐removal (CBR), which includes excavation, transportation, and disposal of the CCR into a lined landfill. This article provides a methodology and a case study of how green and sustainable remediation concepts, including accounting for the life cycle environmental footprints and the physical risks to workers and community members, can be incorporated into the closure decision‐making process. The environmental impacts, occupational risks, and traffic‐related fatalities and injuries to workers and community members were calculated and compared for closure alternatives at a hypothetical site. The results demonstrated that the adverse impacts of the CBR option were significantly greater than those of the CIP option with respect to the analyzed impact pathways.     

Colonized beads as inoculum for marine biodegradability assessment: Application to Linear Alkylbenzene Sulfonate

An innovative biodegradation test system was developed in order to fill the current gap for cost effective and environmentally relevant tools to assess marine biodegradability. Glass beads were colonized by a biofilm in an open flow-through system of seawater with continuous pre-exposure to Linear Alkylbenzene Sulfonate (LAS) (20 μg/L). Thereafter, such colonized beads were added as inoculum in different test systems. [¹⁴C]-LAS (5–100 μg/L) was added and primary and ultimate biodegradation were assessed. The bacterial density collected on the beads (10⁹ bact./mL beads) was ca. 3 orders of magnitude higher than the typical seawater content. The LAS mineralization lag phase duration decreased from 55 to < 1 days and the mineralization extent increased from 53 to 90% as the colonized beads volume increased from 10 to 275 mL. This is the first demonstration of marine bacteria's ability to mineralize LAS. On the opposite, less than 13% LAS was mineralized in seawater only. The colonized beads possibly enhanced the probability to encounter the full degraders' consortium in a low volume of seawater (100 mL).     

Field Evaluation of DRAINMOD 5.1 Under a Cold Climate: Simulation of Daily Midspan Water Table Depths and Drain Outflows1

Abstract: The hydrologic performance of DRAINMOD 5.1 was assessed for the southern Quebec region considering freezing/thawing conditions. A tile drained agricultural field in the Pike River watershed was instrumented to measure tile drainage volumes. The model was calibrated using water table depth and subsurface flow data over a two‐year period, while another two‐year dataset served to validate the model. DRAINMOD 5.1 accurately simulated the timing and magnitude of subsurface drainage events. The model also simulated the pattern of water table fluctuations with a good degree of accuracy. The R² between the observed and simulated daily WTD for calibration was >0.78, and that for validation was 0.93. The corresponding coefficients of efficiency (E) were >0.74 and 0.31. The R² and E values for calibration/validation of subsurface flow were 0.73/0.48 and 0.72/0.40, respectively. DRAINMOD simulated monthly subsurface flow quite accurately (E > 0.82 and R² > 0.84). The model precisely simulated daily/monthly drain flow over the entire year, including the winter months. Thus DRAINMOD 5.1 performed well in simulating the hydrology of a cold region.     

Incorporating organizational factors into probabilistic risk assessment of complex socio-technical systems: Principles and theoretical foundations

The current generation of Probabilistic Risk Analysis (PRA), particularly those for technical systems, does not include an explicit representation of the possible impacts of organization and management on the safety performance of equipment and personnel. There are a number of technical challenges in developing a predictive model of organizational safety performance. There is a need for a widely accepted and theoretically sound set of principles on which models of organizational influences could be developed and validated. As a result of a multidisciplinary effort, this paper explores the feasibility of developing such principles and proposes a set of principles for organizational safety risk analysis. Then, as a realization of the proposed modeling principles, a safety risk framework, named Socio-Technical Risk Analysis (SoTeRiA), is developed. SoTeRiA formally integrates the technical system risk models with the social (safety culture and safety climate) and structural (safety practices) aspects of safety prediction models, and provides a theoretical basis for the integration. A systematic view of safety culture and safety climate leaves an important gap in modeling complex system safety risk, and SoTeRiA, describing the relationship between these two concepts, bridges this gap. The framework explicitly recognizes the relationship among constructs at multiple levels of analysis, and extends the PRA framework to include the effects of organizational factors in a more comprehensive and defensible way.     

Design,measurement and evaluation of photovoltaic pumping system for rural areas in Oman

In the present paper, the optimum design of a PV system used to operate a water pumping system was determined for Oman. The system design focused on the environmental conditions of Sohar city. The implementation and measurement of the designed system are presented to prove the effectiveness of the proposed system. The results show that the system can provide the required power at peak hours, leading to a substantial reduction in the sizing of the PV system. Consequently, the investment capital costs 2400 USD, and the cost of energy is equal to 0.309 USD/kWh. Furthermore, the results indicate that the system annual yield factor is 2024.66 kWh/kWp and that the capacity factor is 23.05 %, which is encouraging since the latter is typically 21 %. The system capital cost and the cost of energy are worth comparing to a diesel generator. A comparison is made between the proposed system and several others in the literature. The comparison indicated that the system cost of energy is promising.     

Proposing of new building scheme and composite towards global warming mitigation for Malaysia

The building sector has been regarded as a potential sector where there is large capacity to reduce the climate change effect. This study has proposed solutions to mitigate environmental impacts and achieve low CO₂ emission from residential sector. Therefore, full life cycle assessment (LCA) has been run to assess the CO₂ emission and its effect on the atmosphere and climate change. Based on the result, timber scheme is the best choice due to releasing less CO₂ emissions to the atmosphere. However, house builders in Malaysia have almost completely neglected timber as a building material, with timber use as building components reduced to 5%. In this study, LCA Software was used to assess CO₂ emissions from different wall construction. The alternative building scheme has been made by reinforce steel stud, wooden beam and timber wall (S8) to improve the scheme deficiency while releasing less CO₂ emissions compared to other schemes. Therefore, S8 has a decreased CO₂ effect by 85% less than precast concrete frame and 90% less than brick over their lifetime. (S8) increased the load bearing compared to conventional timber beam. Thus, new scheme S8 could be replaced by current scheme and promote more adjustable scheme for Malaysian housing.     

Proximate composition and mineral contents in the body wall of two species of sea cucumber from Oman Sea

The proximate composition and mineral contents of Stichopus horrens and Holothuria arenicola from Chabahar Bay were analyzed and investigated. During the present study, we aimed to demonstrate the nutritive value. The approximate percent composition of moisture, protein, fat, and ash were 92.8, 3.47, 0.4, and 3.33% in S. horrens and 93, 4.4, 0.6, and 2% in H. arenicola, respectively. Atomic absorption spectrophotometry of the ashes indicated the body wall of two species of sea cucumbers contained higher amounts of both macro minerals (92.5 mg/100 g Mg in S. horrens and 115 mg/100 g Mg in H. arenicola; 106.25 mg/100 g Ca in S. horrens and 83.25 mg/100 g Ca in H. arenicola) and trace elements (521.781 mg/100 g Fe in S. horrens; 60.354 mg/100 g Fe in H. arenicola, and 0.096 mg/100 g Zn in S. horrens; 0.04 mg/100 g Zn in H. arenicola). For both species, there were high content of protein and essential mineral. Also, they have low content of fat in the body wall of two species in the experiment.     

Model and algorithm for bi-fuel vehicle routing problem to reduce GHG emissions

Because of the harmful effects of greenhouse gas (GHG) emitted by petroleum-based fuels, the adoption of alternative green fuels such as biodiesel and compressed natural gas (CNG) is an inevitable trend in the transportation sector. However, the transition to alternative fuel vehicle (AFV) fleets is not easy and, particularly at the beginning of the transition period, drivers may be forced to travel long distances to reach alternative fueling stations (AFSs). In this paper, the utilization of bi-fuel vehicles is proposed as an operational approach. We present a mathematical model to address vehicle routing problem (VRP) with bi-fuel vehicles and show that the utilization of bi-fuel vehicles can lead to a significant reduction in GHG emissions. Moreover, a simulated annealing algorithm is adopted to solve large instances of this problem. The performance of the proposed algorithm is evaluated on some random instances.     

Microwave irradiation and citric acid assisted seed germination and phytoextraction of nickel (Ni) by <Emphasis Type="Italic">Brassica napus</Emphasis> L.: morpho-physiological and biochemical alterations under Ni stress

The complex bio-geochemistry of soil allows pollutant to persist for a longer period of time which further decreased the fertility and natural composition of land. Nickel, an inorganic pollutant, coming from a wide range of industrial and manufacturing units possesses serious threat to soil degradation and crop productivity around the world. The present study was carried to evaluate the combined role of microwave irradiation (MR) and citric acid (CA) on the phytoextraction potential of Brassica napus L. under Ni stress. An initial seed germination test was conducted to select effective time scale of MR exposure. Highest seed germination was observed at exposure of 2.45 GHz frequency for 30 s. Healthy seeds of B. napus L. genotype Faisal Canola (RBN-03060) treated with MR at 2.45 GHz for 30 s were sown in plastic pots filled with 5 kg of soil. Nickel and CA applied exogenously in solution form with different combinations to both MR-treated and untreated B. napus plants. The MR-treated plants showed higher growth, biomass, photosynthetic pigments (Chl a, b, total, and carotenoids) and activities of antioxidant enzymes (SOD, POD, APX, CAT) as compared to untreated plants who showed higher reactive oxygen species (MDA, H₂O₂) and electrolyte leakage. Increasing Ni concentration significantly decreased the physiological and biochemical attributes of B. napus both in MR-treated and untreated plants. The addition of CA alleviated Ni-induced toxic effects in both MR-treated and untreated plants by improving antioxidant defense system. The degree of Ni stress mitigation was higher in MR-treated plants. The Ni concentration was higher in root, stem, and leaves of MR-treated plants under CA application as compared to untreated plants. The present study concluded that seeds treated with MR before sowing showed higher accumulation and concentration of Ni from soil, and this phenomenon boosted with the application of CA.