Search

Parabolic trough collector stands out as the most proven and widely adopted technology for concentrating solar power. A simple mathematical model based on dividing the trough’s aperture and the surface of the absorber into small segments is developed herein. The model is used to investigate the influence of the design and operational parameters on the distribution of the concentrated solar flux over. In this study, eight absorbers with different geometries are considered and the effect of the rim angle, absorber’s geometry, and operational mode on the distribution of the concentrated solar flux over their surfaces have been addressed. For all absorbers, it has been found that increasing the rim angle results in reducing the intensity of the concentrated solar flux with increase in its coverage area. The distribution of the concentrated solar flux over the surface of the parabolic shaped absorber (ABS.6) is found to be uniform over the portion of the surface located between its two rims. It has also been demonstrated that the operation under free absorber mode can help in redistributing the concentrated solar flux over the absorber surface resulting in a more uniform distribution compared to that over the surface of the fixed absorber. From the combined geometries of the investigated absorbers two optimal shapes are obtained and are found to perform much better than the circular absorber ABS.1.

We identified and investigated the biological activities of Thermomonas hydrothermalis, isolated bacteria strains present in Jordan's hot springs, based on their morphological, biochemical, and physiological characteristics. The colonies exhibited light brown with a diameter ranging from 0.5 to 2.0 mm. For screening their metabolic activities, API 50CHB strips and esculin were used. We phylogenetically typified the isolated bacteria by applying 16S ribosomal DNA gene amplification and sequencing followed by the Basic Local Alignment Search Tool (BLAST) tests. About 100 μL of the enriched sample was streaked on nutrient agar using a calibrated wire loop, while 20 μg crude powder was mixed with dimethyl sulfoxide (DMSO) to test their activities against standard pathogenic bacterial strains (ATCC). The water samples collected from the hot springs had temperatures ranging between 44–56 °C, pH between 7.11–8.51, and electrical conductivity between 1.06–1.41 ms/cm. To utilize their isolate for characterization and applications, pH, temperature, and generation time were optimized. It was found that the Gram-negative isolated bacteria strain exhibited an optimum growth at 55 °C, pH 8.5, and 30 min of generation time (GT). The BLAST results showed a 99 % of similar identity of the sample to Thermomonas hydrothermalis. Due to their antibacterial effects against Gram-positive and Gram-negative bacteria, bioactive compounds identified using gas chromatography–mass spectroscopy (GC–MS) had novel features such as 4(3 H)-pyrimidinone, dihydroxy-1,5- naphthyridine, actinomycine-D, and pyrrolo [1,2-a]pyrazine-1,4-dione hygrazides. Screening of cytotoxic activity tests using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was conducted toward their water extract, which exerted cytostimulatory effects on human lung fibroblasts (MRC-5) with an IC50 of 5.109 μg/mL and accelerated wound closure. Overall, the implications of this study provided new insights into the bioproducts of Thermomonas hydrothermalis and offered opportunities to utilize their isolate for biotechnological and medicinal applications.

Acetaminophen (Ace) is a trace pollutant widely found in sewage treatment plant (STP) wastewater. We test the feasibility of coconut shell waste, a low cost adsorbent from coconut industry, for removing Ace from synthetic solution in a fixed-bed column adsorption. To enhance its performance, the surface of granular activated carbon (GAC) was pre-treated with NaOH, HNO3, ozone, and/or chitosan respectively. The results show that the chemical modification of the GAC's surface with various chemicals has enhanced its Ace removal during the column operations. Among the modified adsorbents, the ozone-treated GAC stands out for the highest Ace adsorption capacity (38.2 mg/g) under the following conditions: 40 mg/L of Ace concentration, 2 mL/min of flow rate, 45 cm of bed depth. Both the Thomas and the Yoon-Nelson models are applicable to simulate the experimental results of the column operations with their adsorption capacities: ozone-treated GAC (20.88 mg/g) > chitosan-coated GAC (16.67 mg/g) > HNO3-treated GAC (11.09 mg/g) > NaOH-treated GAC (7.57 mg/g) > as-received GAC (2.84 mg/g). This suggests that the ozone-treated GAC is promising and suitable for Ace removal in a fixed-bed reactor.

Camelina sativa is a cool-season oil seed crop that has been proven to produce various biofuels. The present study investigated the technical possibilities of using whole camelina biomass as a model feedstock in a biorefinery. This investigation examined the possibilities of using camelina seeds as a source of oil for biodiesel, sugars for ethanol, and meal for one-portfolio products. The camelina harvest residues (straw) can serve as the main source for green sugars. This study found that the energy input for the whole biorefinery process was 25.1 MJ/L ethanol, while the energy output was 54.3 MJ/L ethanol. The net energy ratio of 2.16 MJ/L ethanol was found to be competitive with other energy crops. The process was environmentally friendly, and it reduced greenhouse gas emissions by 40% if the produced biodiesel replaced petroleum diesel. The seed meals and glycerin were found to be a good source of revenue as high value-added products and can provide an additional revenue of $1/kg of produced oil.

Acetaminophen (Ace) is a trace pollutant widely found in sewage treatment plant (STP) wastewater. We test the feasibility of coconut shell waste, a low cost adsorbent from coconut industry, for removing Ace from synthetic solution in a fixed-bed column adsorption. To enhance its performance, the surface of granular activated carbon (GAC) was pre-treated with NaOH, HNO

The effect of relative humidity (RH: 30% to >95%) of a gas-phase mixture composed of benzene, toluene, ethylbenzene and para-, meta- and ortho-xylenes (BTEX), inlet concentrations (0.2–12.6 g m−3), and empty bed residence times (EBRTs) (48–144 s) was tested in a fungi-dominant biofilter. A maximum elimination capacity (ECmax) of 244.2 gBTEX m−3 h−1 was achieved at a total inlet loading rate (ILRT) of 371.2 gBTEX m−3 h−1 (RH: 65%). The transient-state response was tested by increasing the ILRT, in two steps, from ∼50 to 850 g m−3 h−1 and from ∼50 to 320 g m−3 h−1, at a constant EBRT of 41.7 s. Increasing the ILRT reduced the total BTEX removal efficiency (RET) from >97% to 35%, and from >90% to 60% during medium and high shock-load, respectively. When subjected to short (4 d) and long-term (7 d) shut-down periods, the biofilter was able to recover high ECmax of, respectively, 200 and 72 gBTEX m−3 h−1 after resuming operation. Ministerio de Educación y Ciencia; CTM2004-00427/TECNO Ministerio de Educación y Ciencia; SB-2004-0135 Ministerio de Ciencia e Innovación; JCI-2008-0385

A gram-negative, rod-shaped, aerobe, capable of converting 2-propanol (isopropanol, IPA) to acetone was isolated from an oil/sump, and identified by 16 S rDNA analysis as Alcaligenes faecalis. Investigations showed this strain to be extremely solvent-tolerant and it was subsequently named ST1. In this study, A. faecalis ST1 cells were immobilized by entrapment in Ca-alginate beads (3 mm in diameter), and used in the bioconversion of high concentration IPA. The biodegradation rates and the corresponding microbial growth inside the beads were measured at four different IPA concentration ranges from 2 to 15 g l(-1). The maximum cell concentration obtained was 9.59 g dry cell weight (DCW) l(-1) medium which equated to 66 g DCW l(-1) gel, at an initial IPA concentration of 15 g l(-1) after 216 h of incubation. A maximum biodegradation rate of 0.067 g IPA g cells(-1) h(-1) was achieved for 5 g l(-1) IPA where an increase in IPA concentration to 38 g l(-1) caused reduction in bead integrity. A modified growth medium was developed which allowed repeated use of the beads for more than 42 days without any loss of integrity and continued bioconversion activity.

A growing number of marine fungi are the sources of novel and potentially life-saving bioactive secondary metabolites. Here, we have discussed some of these novel antibacterial, antiviral, antiprotozoal compounds isolated from marine-derived fungi and their possible roles in disease eradication. We have also discussed the future commercial exploitation of these compounds for possible drug development using metabolic engineering and post-genomics approaches.

This study compares the removal of a mixture of benzene, toluene, ethylbenzene, and all three xylene isomers (BTEX) in mesophilic and thermophilic (50°C) bioreactors. In the mesophilic reactor fungi became dominant after long-term operation, while bacteria dominated in the thermophilic unit. Microbial acclimation was achieved by exposing the biofilters to initial BTEX loads of 2–15 g m−3 h−1, at an empty bed residence time of 96 s. After adaptation, the elimination capacities ranged from 3 to 188 g m−3 h−1, depending on the inlet load, for the mesophilic biofilter with removal efficiencies reaching 96%. On the other hand, in the thermophilic reactor the average removal efficiency was 83% with a maximum elimination capacity of 218 g m−3 h−1. There was a clear positive relationship between temperature gradients as well as CO2 production and elimination capacities across the biofilters. The gas phase was sampled at different depths along the reactors observing that the percentage pollutant removal in each section was strongly dependant on the load applied. The fate of individual alkylbenzene compounds was checked, showing the unusually high biodegradation rate of benzene at high loads under thermophilic conditions (100%) compared to its very low removal in the mesophilic reactor at such load (

The bioconversion of high concentration isopropanol (2-propanol, IPA) was investigated by a solvent tolerant strain of bacteria, which was identified as Sphingobacterium mizutae ST2 by partial 16S rDNA gene sequencing. This strain of bacteria exhibited the ability to utilise high concentration isopropanol as the sole carbon source, with mineralization occurring via an acetone intermediate into central metabolism. The biodegradative performance of this strain for IPA was examined over a 2-38 g l(-1) concentration range, using specific growth rate (mu) and conversion rate analysis. Maximum specific growth rates (mu(max)) of 0.0045 h(-1 )were routinely obtainable on IPA. In addition, the highest specific IPA degradation rate was obtained at a concentration of 7.5 g l(-1) with a corresponding value of 0.045 g IPA g cells(-1) h(-1). While the highest acetone yield reached its maximum value of 0.940 g acetone g IPA(-1) at 7.5 g IPA l(-1). This is the first report on bioconversion of isopropanol at such high concentration by this solvent tolerant strain of S. mizutae and may allow its application in novel biocatalytic processes for effective biological conversion in two-phase solvent systems.