Now showing items 1-20 of 1643

    • Temperature Responses of Heterotrophic Bacteria in Co-culture With a Red Sea Synechococcus Strain

      Labban, Abbrar; Palacio, Antonio S.; García, Francisca C.; Hadaidi, Ghaida A.; Ansari, Mohd Ikram; López-Urrutia, Ángel; Alonso-Sáez, Laura; Hong, Pei-Ying; Moran, Xose Anxelu G. (Frontiers in Microbiology, Frontiers Media SA, 2021-05-10) [Article]
      Interactions between autotrophic and heterotrophic bacteria are fundamental for marine biogeochemical cycling. How global warming will affect the dynamics of these essential microbial players is not fully understood. The aims of this study were to identify the major groups of heterotrophic bacteria present in a Synechococcus culture originally isolated from the Red Sea and assess their joint responses to experimental warming within the metabolic ecology framework. A co-culture of Synechococcus sp. RS9907 and their associated heterotrophic bacteria, after determining their taxonomic affiliation by 16S rRNA gene sequencing, was acclimated and maintained in the lab at different temperatures (24–34°C). The abundance and cellular properties of Synechococcus and the three dominant heterotrophic bacterial groups (pertaining to the genera Paracoccus, Marinobacter, and Muricauda) were monitored by flow cytometry. The activation energy of Synechococcus, which grew at 0.94–1.38 d–1, was very similar (0.34 ± 0.02 eV) to the value hypothesized by the metabolic theory of ecology (MTE) for autotrophs (0.32 eV), while the values of the three heterotrophic bacteria ranged from 0.16 to 1.15 eV and were negatively correlated with their corresponding specific growth rates (2.38–24.4 d–1). The corresponding carrying capacities did not always follow the inverse relationship with temperature predicted by MTE, nor did we observe a consistent response of bacterial cell size and temperature. Our results show that the responses to future ocean warming of autotrophic and heterotrophic bacteria in microbial consortia might not be well described by theoretical universal rules.
    • A decentralized water/electricity cogeneration system integrating concentrated photovoltaic/thermal collectors and vacuum multi-effect membrane distillation

      Chen, Qian; Burhan, Muhammad; Akhtar, Faheem; Ybyraiymkul, Doskhan; Shahzad, Muhammad Wakil; Li, Yong; Ng, Kim Choon (Energy, Elsevier BV, 2021-05-07) [Article]
      Cogeneration of electricity and freshwater by integrating photovoltaic/thermal collectors and desalination systems is one of the most promising methods to tackle the challenges of water and energy shortage in remote areas. This study investigates a decentralized water/electricity cogeneration system combining concentrated photovoltaic/thermal collectors and a vacuum multi-effect membrane distillation system. The merits of such a configuration include high compactness and improved thermodynamic efficiency. To evaluate the long-term production potential of the proposed system, a thermodynamic analysis is firstly conducted. Under the climatic conditions of Makkah, Saudi Arabia, the system can convert ∼70% of the solar irradiance into useful energy. The annual productivity of electricity and distilled water are 562 kWh and 5.25 m3, respectively, per m2 of the solar collector area. Electricity and water production rates are found to be impacted by hot water flowrate, feed seawater flowrate and heat storage tank dimension, while the overall exergy efficiency stabilizes at 25-27%. Based on the production rates, an economic analysis is conducted through life-cycle cost analysis. The final desalination cost is calculated to be $0.7-4.3/m3, depending on the solar collector cost and the electricity price. The derived results will enable a more in-depth understanding of the proposed solar-driven water/electricity cogeneration system.
    • Solubility and Stability of Some Pharmaceuticals in Natural Deep Eutectic Solvents-Based Formulations.

      Mustafa, Natali Rianika; Spelbos, Vincent Simon; Witkamp, Geert Jan; Verpoorte, Robert; Choi, Young Hae (Molecules (Basel, Switzerland), MDPI AG, 2021-05-05) [Article]
      Some medicines are poorly soluble in water. For tube feeding and parenteral administration, liquid formulations are required. The discovery of natural deep eutectic solvents (NADES) opened the way to potential applications for liquid drug formulations. NADES consists of a mixture of two or more simple natural products such as sugars, amino acids, organic acids, choline/betaine, and poly-alcohols in certain molar ratios. A series of NADES with a water content of 0-30% (w/w) was screened for the ability to solubilize (in a stable way) some poorly water-soluble pharmaceuticals at a concentration of 5 mg/mL. The results showed that NADES selectively dissolved the tested drugs. Some mixtures of choline-based NADES, acid-neutral or sugars-based NADES could dissolve chloral hydrate (dissociated in water), ranitidine·HCl (polymorphism), and methylphenidate (water insoluble), at a concentration of up to 250 mg/mL, the highest concentration tested. Whereas a mixture of lactic-acid-propyleneglycol could dissolve spironolacton and trimethoprim at a concentration up to 50 and 100 mg/mL, respectively. The results showed that NADES are promising solvents for formulation of poorly water-soluble medicines for the development of parenteral and tube feeding administration of non-water-soluble medicines. The chemical stability and bioavailability of these drug in NADES needs further studies.
    • Investigation of flux stability and fouling mechanism during simultaneous treatment of different produced water streams using forward osmosis and membrane distillation.

      Nawaz, Muhammad Saqib; Son, Hyuk Soo; Jin, Yong; Kim,Youngjin; Soukane, Sofiane; Al-Hajji, Mohammed Ali; Abu-Ghdaib, Muhannad; Ghaffour, NorEddine (Water research, Elsevier BV, 2021-05-02) [Article]
      Forward osmosis-membrane distillation (FO-MD) hybrids were recently found suitable for produced water treatment. Exclusion of synthetic chemical draw solutions, typically used for FO, can reduce FO-MD operational costs and ease its onsite application. This study experimentally validates a novel concept for the simultaneous treatment of different produced water streams available at the same industrial site using an FO-MD hybrid system. The water oil separator outlet (WO) stream was selected as FO draw solution and it generated average fluxes ranging between 8.30 LMH and 26.78 LMH with four different feed streams. FO fluxes were found to be governed by the complex composition of the feed streams. On the other hand, with WO stream as MD feed, an average flux of 14.41 LMH was achieved. Calcium ions were found as a main reason for MD flux decline in the form of CaSO4 scaling and stimulating the interaction between the membrane and humic acid molecules to form scale layer causing reduction in heat transfer and decline in MD flux (6%). Emulsified oil solution was responsible for partial pore clogging resulting in further 2% flux decline. Ethylenediaminetetraaceticacid (EDTA) was able to mask a portion of calcium ions and resulted in a complete recovery of the original MD flux. Under hybrid FO-MD experiments MD fluxes between 5.62 LMH and 11.12 LMH were achieved. Therefore, the novel concept is validated to produce fairly stable FO and MD fluxes, with few streams, without severe fouling and producing excellent product water quality.
    • Enzyme catalysis with artificial membranes towards process intensification in biorefinery- A review

      Mazzei, Rosalinda; Yihdego Gebreyohannes, Abaynesh; Papaioannou, Emmaouil; Nunes, Suzana Pereira; Vankelecom, Ivo F.J.; Giorno, Lidietta (Bioresource Technology, Elsevier BV, 2021-05) [Article]
      In this review, for the first time, the conjugation of the major types of enzymes used in biorefineries and the membrane processes to develop different configurations of MBRs, was analyzed for the production of biofuels, phytotherapics, food ingredients, etc. In particular, the aim is to critically review all the works related to the application of MBR in biorefinery, highlighting the advantages and the main drawbacks which can interfere with the development of this system at industrial scale. Alternatives strategies to overcome main limits will be also described in the different application fields, such as the use of biofunctionalized magnetic nanoparticles associated with membrane processes for enzyme re-use and membrane cleaning or the membrane fouling control by the use of integrated membrane process associated with MBR.
    • Experimental investigations of a solar water treatment system for remote desert areas of Pakistan

      Jamil, Muhammad Ahmad; Yaqoob, Haseeb; Farooq, Muhammad Umar; Teoh, Yew Heng; Xu, Ben Bin; Mahkamov, Khamid; Sultan, Muhammad; Ng, Kim Choon; Shahzad, Muhammad Wakil (Water (Switzerland), MDPI AG, 2021-04-13) [Article]
      Pakistan is among the countries that have already crossed the water scarcity line, and the situation is worsened due to the recent pandemic. This is because the major budget of the country is shifted to primary healthcare activities from other development projects that included water treatment and transportation infrastructure. Consequently, water-borne diseases have increased drastically in the past few months. Therefore, there is a dire need to address this issue on a priority basis to ameliorate the worsening situation. One possible solution is to shift the focus/load from mega-projects that require a plethora of resources, money, and time to small domestic-scale systems for water treatment. For this purpose, domestic-scale solar stills are designed, fabricated, and tested in one of the harshest climatic condition areas of Pakistan, Rahim Yar Khan. A comprehensive overview of the regional climatology, including wind speed, solar potential, and ambient temperature is presented for the whole year. The analysis shows that the proposed system can adequately resolve the drinking water problems of deprived areas of Pakistan. The average water productivity of 1.5 L/d/m2 is achieved with a total investment of PKR 3000 (
    • A thermodynamic platform for evaluating the energy efficiency of combined power generation and desalination plants

      Ng, Kim Choon; Burhan, Muhammad; Chen, Qian; Ybyraiymkul, Doskhan; Akhtar, Faheem; Kumja, M.; Field, Robert W.; Shahzad, Muhammad Wakil (npj Clean Water, Springer Science and Business Media LLC, 2021-04-08) [Article]
      In seawater desalination, the energy efficiency of practical processes is expressed in kWh_electricity or low-grade-heat per m3 of water produced, omitting the embedded energy quality underlying their generation processes. To avoid thermodynamic misconceptions, it is important to recognize both quality and quantity of energy consumed. An unmerited quantitative apportionment can result in inferior deployment of desalination methods. This article clarifies misapprehensions regarding seeming parity between electricity and thermal sources that are sequentially cogenerated in power plants. These processes are represented by heat engines to yield the respective maximum (Carnot) work potentials. Equivalent work from these engines are normalized individually to give a corresponding standard primary energy (QSPE), defined via a common energy platform between the adiabatic flame temperature of fuel and the surroundings. Using the QSPE platform, the energy efficiency of 60 desalination plants of assorted types, available from literature, are compared retrospectively and with respect to Thermodynamic Limit.
    • Phylogenomics of Porites from the Arabian Peninsula.

      Terraneo, Tullia Isotta; Benzoni, Francesca; Arrigoni, Roberto; Baird, Andrew H; Mariappan, Kiruthiga; Forsman, Zac H; Wooster, Michael K; Bouwmeester, Jessica; Marshell, Alyssa; Berumen, Michael L. (Molecular phylogenetics and evolution, Elsevier BV, 2021-04-04) [Article]
      The advent of high throughput sequencing technologies provides an opportunity to resolve phylogenetic relationships among closely related species. By incorporating hundreds to thousands of unlinked loci and single nucleotide polymorphisms (SNPs), phylogenomic analyses have a far greater potential to resolve species boundaries than approaches that rely on only a few markers. Scleractinian taxa have proved challenging to identify using traditional morphological approaches and many groups lack an adequate set of molecular markers to investigate their phylogenies. Here, we examine the potential of Restriction-site Associated DNA sequencing (RADseq) to investigate phylogenetic relationships and species limits within the scleractinian coral genus Porites. A total of 126 colonies were collected from 16 localities in the seas surrounding the Arabian Peninsula and ascribed to 12 nominal and two unknown species based on their morphology. Reference mapping was used to retrieve and compare nearly complete mitochondrial genomes, ribosomal DNA, and histone loci. De novo assembly and reference mapping to the P. lobata coral transcriptome were compared and used to obtain thousands of genome-wide loci and SNPs. A suite of species discovery methods (phylogenetic, ordination, and clustering analyses) and species delimitation approaches (coalescent-based, species tree, and Bayesian Factor delimitation) suggested the presence of eight molecular lineages, one of which included six morphospecies. Our phylogenomic approach provided a fully supported phylogeny of Porites from the Arabian Peninsula, suggesting the power of RADseq data to solve the species delineation problem in this speciose coral genus.
    • Digital insights: bridging the phenotype-to-genotype divide

      McCabe, Matthew; Tester, Mark A. (Journal of Experimental Botany, Oxford University Press (OUP), 2021-04-02) [Article]
      The convergence of autonomous platforms for field-based phenotyping with advances in machine learning for big data analytics and rapid sequencing for genome description herald the promise of new insights and discoveries in the plant sciences. Han et al. (2021) leverage these emerging tools to navigate the challenging path from field-based mapping of phenotypic features to identifying specific genetic loci in the laboratory: in this case, loci responsible for regulating daily flowering time in lettuce. While their contribution neatly illustrates these exciting technological developments, it also highlights the work that remains to bridge these multidisciplinary fields to more fully deliver upon the promise of digital agriculture.
    • Assimilation of soil moisture and canopy cover data improves maize simulation using an under-calibrated crop model

      Lu, Yang; Chibarabada, Tendai P.; Ziliani, Matteo G.; Onema, Jean Marie Kileshye; McCabe, Matthew; Sheffield, Justin (Agricultural Water Management, Elsevier BV, 2021-04-02) [Article]
      Parameter calibration is normally required prior to crop model simulation, which can be a time-consuming and data-intensive task. Meanwhile, the growth stages of different hybrids/cultivars of the same crop often show some similarities, which implies that phenological parameters calibrated for one hybrid/cultivar may be useful for the simulation of another. In this study, a data assimilation framework is proposed to reduce the requirement for parameter calibration for maize simulation using AquaCrop. The phenological parameters were uniformly scaled from previous research performed in a different location for a different maize hybrid, and other parameters were taken from default settings in the model documentation. To constrain simulation uncertainties, soil moisture and canopy cover observations were assimilated both separately and jointly in order to update model states. The methodology was tested across a rain-fed field in Nebraska for 6 growing seasons. The results suggested that the under-calibrated model with uniformly scaled phenological parameters captured the temporal dynamics of crop growth, but may lead to large estimation bias. Data assimilation effectively improved model performance, and the joint assimilation outperformed single-variable assimilation. When soil moisture and canopy cover were jointly assimilated, the overall yield estimates (RMSE = 1.24 t/ha, nRMSE = 11.48%, R2 = 0.695) were improved over the no-assimilation case (RMSE = 2.01 t/ha, nRMSE = 18.61%, R2 = 0.338). Sensitivity analyses suggested that the improvement was still evident with temporally sparse soil moisture observations and a small ensemble size. Further testing using observations within 90 days after planting demonstrated that the method was able to predict yield around 3 months before harvest (RMSE = 1.7 t/ha, nRMSE = 15.74%). This study indicated that maize yield can be estimated and predicted accurately by monitoring the soil moisture and canopy status, which has potential for regional applications using remote sensing data.
    • Moving Towards Water Security: Mitigating Emerging Contaminants in Treated Wastewater for Sustainable Reuse

      Augsburger, Nicolas (2021-04) [Dissertation]
      Advisor: Hong, Pei-Ying
      Committee members: Daffonchio, Daniele; Saikaly, Pascal; Lee, Yunho
      Continuous increases in the interest and implementation of wastewater reuse due to intensified water stress has escalated the concerns of emerging contaminants. Among emerging contaminants there are microbial (antibiotic resistance) and chemical (pharmaceuticals) elements which have been shown to survive wastewater treatment. This dissertation aims to mitigate emerging contaminants by means of understanding and/or developing the appropriate disinfection strategies, with the intention to provide knowledge that would facilitate towards safe and sustainable water reuse. The first part of this thesis explored microbial risk component of antibiotic resistance. Antibiotic resistance genes are abundant in treated wastewater, and only pose a risk if taken up by potential pathogens through natural transformation. Our results showed that solar irradiation can double natural transformation rates, mediated by reactive oxygen species generation, which led to upregulation in DNA repair and competence genes in Acinetobacter baylyi ADP1. Treatment with UV-C254 nm irradiation also resulted in upregulation in DNA repair genes, nevertheless we observed a decrease in natural transformation rates. These results imply that direct damage of antibiotic resistance genes (ARG) could inhibit their spread and therefore risk, despite other factors contributing to the contrary. The next chapter in this dissertation postulated that the UV/H2O2 combination would be ideal to treat microbial and chemical emerging contaminants in effluent generated from an anaerobic membrane bioreactor. We demonstrated that at an optimal UV intensity and H2O2 concentration, we were able to achieve a 2 and 6-log reduction of the two antibiotic resistance genes and bacteria and used in this study, respectively, and more than 90% removal of the three pharmaceutical compounds. These observations suggest that UV/H2O2 has great potential in treating effluent with high nitrogen concentrations, preserving the fertilization benefit of AnMBR effluent. Overall, this dissertation revealed the potential of UV-based treatments for treated wastewater intended for reuse. Post-membrane processes effluent allows one to deploy UV-C254 nm to selectively target DNA and therefore ARB and ARG that may be still present in the treated wastewater. At the same time, coupling chemical oxidants with UV-C (i.e., UV AOP) would further enhance the means to simultaneously oxidize and degrade potentially harmful chemical contaminants.
    • Using Google Earth Engine for the Automated Mapping of Center Pivot Irrigation fields in Saudi Arabia

      Alwahas, Areej (2021-04) [Thesis]
      Advisor: McCabe, Matthew
      Committee members: Johansen, Kasper; Picioreanu, Cristian; Schuster, Gerard T.
      Groundwater is a vital non-renewable resource that is being over exploited at an alarming rate. In Saudi Arabia, the majority of groundwater is used for agricultural activities. As such, the mapping of irrigated lands is a crucial step for managing available water resources. Even though traditional in-field mapping is effective, it is expensive, physically demanding, and spatially restricted. The use of remote sensing combined with advanced computational approaches provide a potential solution to this scale problem. However, when attempted at large scales, traditional computing tends to have significant processing and storage limitations. To address the scalability challenge, this project explores open-source cloud-based resources to map and quantify center-pivot irrigation fields on a national scale. This is achieved by first applying a land cover classification using Random Forest which is a machine learning approach, and then implementing a circle detection algorithm. While the analysis represents a preliminary exploration of these emerging cloud-based techniques, there is clear potential for broad application to many problems in the Earth and environmental sciences.
    • Microfluidic Integrated Organic Electrochemical Transistor with a Nanoporous Membrane for Amyloid-β Detection

      Koklu, Anil; Wustoni, Shofarul; Musteata, Valentina-Elena; Ohayon, David; Moser, Maximilian; McCulloch, Iain; Nunes, Suzana Pereira; Inal, Sahika (ACS Nano, American Chemical Society (ACS), 2021-03-30) [Article]
      Alzheimer’s disease (AD) is a neurodegenerative disorder associated with a severe loss in thinking, learning, and memory functions of the brain. To date, no specific treatment has been proven to cure AD, with the early diagnosis being vital for mitigating symptoms. A common pathological change found in AD-affected brains is the accumulation of a protein named amyloid-β (Aβ) into plaques. In this work, we developed a micron-scale organic electrochemical transistor (OECT) integrated with a microfluidic platform for the label-free detection of Aβ aggregates in human serum. The OECT channel–electrolyte interface was covered with a nanoporous membrane functionalized with Congo red (CR) molecules showing a strong affinity for Aβ aggregates. Each aggregate binding to the CR-membrane modulated the vertical ion flow toward the channel, changing the transistor characteristics. Thus, the device performance was not limited by the solution ionic strength nor did it rely on Faradaic reactions or conformational changes of bioreceptors. The high transconductance of the OECT, the precise porosity of the membrane, and the compactness endowed by the microfluidic enabled the Aβ aggregate detection over eight orders of magnitude wide concentration range (femtomolar–nanomolar) in 1 μL of human serum samples. We expanded the operation modes of our transistors using different channel materials and found that the accumulation-mode OECTs displayed the lowest power consumption and highest sensitivities. Ultimately, these robust, low-power, sensitive, and miniaturized microfluidic sensors helped to develop point-of-care tools for the early diagnosis of AD.
    • Novel hole-pillar spacer design for improved hydrodynamics and biofouling mitigation in membrane filtration.

      Qamar, Adnan; Kerdi, Sarah; Ali, Syed Muztuza; Shon, Ho Kyong; Vrouwenvelder, Johannes S.; Ghaffour, NorEddine (Scientific reports, Springer Nature, 2021-03-27) [Article]
      Feed spacers are the critical components of any spiral-wound filtration module, dictating the filtration performance. Three spacer designs, namely a non-woven commercial spacer (varying filament cross-section), a symmetric pillar spacer, and a novel hole-pillar spacer (constant filament diameter) were studied using Direct Numerical Simulations (DNS), 3-D printed and subsequently experimentally tested in a lab-scale ultrafiltration set-up with high biofouling potential feed water at various feed pressures. Independent of the applied pressure, the novel hole-pillar spacer showed initially the lowest feed channel pressure drop, the lowest shear stress, and the highest permeate flux compared to the commercial and pillar spacers. Furthermore, less biofilm thickness development on membrane surface was visualized by Optical Coherent Tomography (OCT) imaging for the proposed hole-pillar spacer. At higher feed pressure, a thicker biofilm developed on membrane surface for all spacer designs explaining the stronger decrease in permeate flux at high pressure. The findings systematically demonstrated the role of various spacer designs and applied pressure on the performance of pre-treatment process, while identifying specific shear stress distribution guidelines for engineering a new spacer design in different filtration techniques.
    • Real-Time Personal Fever Alert Monitoring by Wearable Detector Based on Thermoresponsive Hydrogel

      Wang, Wenbin; Wu, Chen; Zhu, Kai; Chen, Fang; Zhou, Jingjing; Shi, Yusuf; Zhang, Chenlin; Li, Renyuan; Wu, Mengchun; Zhuo, Sifei; Zhang, Hepeng; Wang, Peng (ACS Applied Polymer Materials, American Chemical Society (ACS), 2021-03-23) [Article]
      Quick fever screening at a mass scale is proven effective during a pandemic to single out the ones with suspected symptoms of infectious diseases. However, achieving affordable and real-time fever alert at an individual level, although more preferable, remains elusive. Herein, we report an inexpensive and highly sensitive fever detector, which possesses a sharp color transition temperature window tailor-tuned for fever screening. The sensing component of the detector is rationally designed thermoresponsive agarose@poly(N-isopropylacrylamide)-co-acrylamide hydrogel. The hydrogel turns from transparent to opaque white when its temperature is higher than its cloud point. As a proof of concept of its practical applicability, a wearable fever monitoring device was fabricated in the form of a wristband. When the wrist temperature is higher than the threshold of a human fever, the device shows a remarkable color change, alerting an elevated body temperature. The wearable detector provides a promising strategy for real-time fever alert monitoring and is capable of making contributions to inhibit the spread of infectious diseases during a pandemic.
    • Optimizing the energy recovery section in thermal desalination systems for improved thermodynamic, economic, and environmental performance

      Jamil, Muhammad Ahmad; Goraya, Talha S.; Ng, Kim Choon; Zubair, Syed M.; Xu, Ben Bin; Shahzad, Muhammad Wakil (International Communications in Heat and Mass Transfer, Elsevier BV, 2021-03-23) [Article]
      Integration of energy recovery section with thermal desalination systems improves their performance from thermodynamics, economics, and environmental viewpoints. This is because it significantly reduces input energy, heat transfer area, and capital cost requirements. Above all, the system outlet streams can achieve thermal equilibrium with the environment by supplying heat for useful preheating purposes thus reducing the environmental impacts. The plate heat exchangers are generally employed for this purpose as preheaters. The current paper presents a comprehensive investigation and optimization of these heat exchangers for thermal desalination systems applications. An experimentally validated numerical model employing Normalized Sensitivity Analysis and Genetic Algorithm based cost optimization is developed to investigate their performance at assorted operating conditions. The analysis showed that the heat transfer coefficient, pressure drop, and outlet water cost were improved by an increase in feed flow rate. However, with an increased flow rate, the comprehensive output parameter (h/ΔP) decreased due to the high degree increase in pressure drop. Moreover, an increase in the chevron angle reduced the heat transfer coefficient, pressure drop, and water cost. Finally, the optimization lowered the heat transfer area by ~79.5%, capital investment by ~62%, and the outlet cost of the cold stream by ~15.7%. The operational cost is increased due to the increased pressure drop but the overall impact is beneficial as Ctotal of equipment is reduced by ~52.7%.
    • Monitoring of hollow fiber module velocity field and fouling inside individual fibers using benchtop MRI

      Yan, Bin; Bristow, Nicholas W.; Vogt, Sarah J.; Vrouwenvelder, Johannes S.; Johns, Michael L.; Fridjonsson, Einar O. (Journal of Membrane Science, Elsevier BV, 2021-03-22) [Article]
      Ultrafiltration (UF) membrane modules are a viable pre-treatment technology for reverse osmosis processes; they however are susceptible to fouling. In the current study, we demonstrate the use of benchtop MRI to provide quantitative structural and velocity images of an UF membrane module showing velocity inside each individual fiber and proceed to provide unique insights into both subsequent fouling and cleaning events. The module consists of 400 fibers, these all were correctly identified from the MRI images based on an implemented fiber identification algorithm. Velocity imaging of the UF module, revealed significant water flow in only 91% of the fibers. Following fouling with a calcium alginate gel, only 73% of the fibers were observed to be active which only recovered to 79% on application of a cleaning protocol using acetic acid. Fouling was clearly isolated to specific fibers in which flow was effectively eliminated; this is not consistent with the assumption of uniform fouling deposition on the inner fiber walls. This also restricts the access of cleaning solutions which effectively by-pass the fouled fibres. This level of novel, quantitative insight is available on benchtop MRI equipment, which displays significant promise for further hollow fiber UF module design, manufacturing and fouling development and control studies.
    • Neotype designation and re-description of Forsskål’s reticulate whipray Himantura uarnak

      Borsa, Philippe; Williams, Collin T.; Mcivor, Ashlie; Hoareau, Thierry B.; Berumen, Michael L. (Marine Biodiversity, Springer Nature, 2021-03-17) [Article]
      A continuing impediment to the taxonomy of the reticulate whipray Himantura spp. species complex is the absence of a type specimen for H. uarnak (Gmelin [ex Forsskål], 1789). Here, reticulate whipray specimens were sampled from the Jeddah region in the Red Sea, the assumed type locality of H. uarnak, and characterized genetically at the cytochrome-oxidase subunit 1 (CO1) locus. One of these specimens now in the fish collection of the California Academy of Sciences was designated as neotype. The maximum-likelihood phylogeny of all available CO1 gene sequences from the genus Himantura had the following topology: ((H. leoparda, H. uarnak), (H. undulata, (Himantura sp. 2, (H. australis + Himantura sp. 1))), H. tutul), where H. uarnak haplotypes formed a distinct lineage sister to H. leoparda. Based on these CO1 gene sequences, the geographic distribution of H. uarnak includes the eastern Mediterranean, the Red Sea, the East African coast, and the Arabian Sea. At least one lineage in the reticulate whipray species complex remains to be named.
    • State-of-the-art of renewable energy sources used in water desalination: Present and future prospects

      Bundschuh, Jochen; Kaczmarczyk, Michał; Ghaffour, NorEddine; Tomaszewska, Barbara (Desalination, Elsevier BV, 2021-03-16) [Article]
      The last decade has seen a worldwide increase in the use of alternative energy sources, especially renewable energy (RE), including its application in desalination. In the past many experimental and pilot investigations were presented which allowed the costs and effectiveness of such integrated solutions to be estimated. The present review describes experience related to the use of solar thermal technologies (solar collector and concentrated solar power technologies), solar electricity (photovoltaic and concentrator photovoltaics), wind, hydroelectric (hydropower, tidal, wave and ocean thermal energy), biomass and geothermal energy (power and thermal) as well as hybrid systems. The costs relating to energy and desalinated water production are investigated in the case of various technological processes used in desalination. The main directions for development of the RE systems investigated are discussed and their advantages and disadvantages are assessed. Such a comprehensive review showed that the expansion of the effective use of RE sources is still hampered by several techno-economic aspects. The paper focuses on the main concerns of the need to optimise energy processes, especially by creating more energy-efficient and economically effective solutions, energy storage, energy recovery and the expansion of off-grid systems. As a result of the analysis it was concluded that, despite some disadvantages, the combining of RE with desalination processes requires further intensive research and demonstration units for longer term performance. Regulations to develop less energy-intensive desalination technologies are also still needed.
    • Microbial Succession under Freeze–Thaw Events and Its Potential for Hydrocarbon Degradation in Nutrient-Amended Antarctic Soil

      Jesus, Hugo Emiliano de; Carreira, Renato S.; Paiva, Simone S. M.; Massone, Carlos; Enrich-Prast, Alex; Peixoto, Raquel S.; Rodrigues, Jorge L. Mazza; Lee, Charles K.; Cary, Craig; Rosado, Alexandre S. (Microorganisms, MDPI AG, 2021-03-16) [Article]
      The polar regions have relatively low richness and diversity of plants and animals, and the basis of the entire ecological chain is supported by microbial diversity. In these regions, understanding the microbial response against environmental factors and anthropogenic disturbances is essential to understand patterns better, prevent isolated events, and apply biotechnology strategies. The Antarctic continent has been increasingly affected by anthropogenic contamination, and its constant temperature fluctuations limit the application of clean recovery strategies, such as bioremediation. We evaluated the bacterial response in oil-contaminated soil through a nutrient-amended microcosm experiment using two temperature regimes: (i) 4 °C and (ii) a freeze–thaw cycle (FTC) alternating between −20 and 4 °C. Bacterial taxa, such as Myxococcales, Chitinophagaceae, and Acidimicrobiales, were strongly related to the FTC. Rhodococcus was positively related to contaminated soils and further stimulated under FTC conditions. Additionally, the nutrient-amended treatment under the FTC regime enhanced bacterial groups with known biodegradation potential and was efficient in removing hydrocarbons of diesel oil. The experimental design, rates of bacterial succession, and level of hydrocarbon transformation can be considered as a baseline for further studies aimed at improving bioremediation strategies in environments affected by FTC regimes.