Groundwater desalination using forward Osmosis in Egypt

Rapid population growth is putting huge stress on limited fresh water sources in Egypt. Agriculture is considered the major consumer of fresh water in Egypt, consuming more than 80% of fresh water available. Creating new freshwater sources for irrigation purposes becomes inevitable to meet the increasing demand. Groundwater desalination could be the solution to this problem. If a low-cost sustainable desalination technology is realized, impact on the agricultural sector would be remarkable for water stressed country like Egypt. Forward Osmosis (FO) is an innovative membrane separation technology that can be applied to efficiently desalinate groundwater. FO desalination relies on the theory of natural osmotic pressure driven by concentration difference instead of hydraulic pressure in RO (Reverse Osmosis). Thus, desalination can be achieved using significantly low energy. FO desalination process involves the use of a concentrated draw solution (DS), generating elevated osmotic pressure, flowing on one side of a semi-permeable FO membrane, and a feed solution (FS), with a lower osmotic pressure, flowing by the other side. Fresh water leaves the FS and enters the DS by natural diffusion. The diluted DS is then separated from the fresh water and draw solutes are recovered. One application of FO process is Fertilizer Drawn Forward Osmosis (FDFO). This application offers a unique advantage as separation and recovery of draw solute is not essential since the draw solution adds value to the end product. The convenience of FDFO desalination is that produced water can be directly utilized for fertigation because fertilizers are needed anyway for the plants avoiding the need for separation and recovery of draw solutes. However, FDFO desalination has some limitations that should be considered. Novel draw solutions and capable FO membranes are the main concern of most FO researchers as both greatly affect overall process efficiency. The high nutrient content in product water is another limitation making meeting irrigation water quality standards a challenge. Applying FDFO technology in Egypt for augmenting irrigation water by desalinating abundant brackish groundwater is investigated in this work. As Egypt is a groundwater-rich country, application of FDFO desalination technology would lead to a revolutionary platform where unutilized brackish groundwater can be efficiently made use of to generate valuable nutrient-rich irrigation water. Egyptian irrigation schemes and mapping of groundwater aquifers in Egypt have been carefully investigated. Based on a carefully studied selection criteria, two proposed locations are suggested for this application in Egypt: 1) Nile Valley and Delta region and 2) Red Sea coast in Eastern Desert and Sinai region. In Nile valley and Delta region, it is suggested to apply FDFO technology coupled with localized irrigation instead of flood irrigation. The suggested technique could possibly cultivate 1 million feddan using renewable groudnwater. Proposed scheme will lead to a healthier Nile River and is expected to eventually minimize further soil salinization being a reported problem in the area which negatively affects crop yield In Red Sea coast in Eastern Desert and Sinai region, FDFO desalination is a promising technology to help alleviate the severe water scarcity problem inhibiting the area’s development. Already existing RO facilities could be easily integrated to the suggested FDFO technology. In this study it is suggested to have decentralized small-scale farms, instead of hundreds of thousands of feddan as is common in Delta and Nile valley regions. This will minimize water losses and keep the desalinated water at a competitive price. FDFO desalination success is greatly affected by the choice of a suitable draw solution. This study focused only on nitrogenous-based fertilizers being by far the most dominant class of fertilizers used in Egypt. Four nitrogenous Egyptian fertilizers have been closely evaluated with respect to their availability, economics and performance. The three factors played a major role in the fertilizer selection. Ammonium Sulpahte was selected to be the most suitable fertilizer draw solution exhibiting high osmotic pressure, being non-expensive, non hygroscopic, resistant to valorization, highly soluble in water and containing sulphur which is needed by the plant. Performance of ammonium sulphate DS was then tested experimentally. The FO membrane used was thin film composite (TFC) membrane supplied by Woongjin, Korea and fhe FS was synthetic salty water prepared using different concentrations of NaCl. A bench-scale FO setup was used to run the experiments. The performance was assessed based on water flux, reverse permeation and feed ions rejection at different DS concentration. It is concluded that there is a logarithmic correlation between flux and ammonium sulphate concentration where any additional increase in ammonium sulphate concentration inhibits water flux due to dilutive internal concentration polarization (DICP) effects. Increasing FS concentration leads to flux decline due to the drop in the differential bulk osmotic pressures between DS and FS. Specific Reverse Solute Flux (SRSF) values at flux less than 10 Lm-2h-1 is significantly higher than that for flux more than 10 Lm-2h-1. As a result, it is recommended to operate the process at a flux exceeding 10 Lm-2h-1 to avoid undesired loss of draw solute by reverse permeation. SRSF is almost constant irrespective of ammonium sulphate DS concentration. For the same DS concentration, flux and SRSF are inversely proportional. Except when operated at low ammonium sulphate concentration and high FS concentration, the TFC membrane used in this study exhibited high rejection of FS ions for almost all DS concentrations (more than 90%). To sensibly test the efficiency of the ammonium sulphate draw solution, a real brackish Egyptian groundwater sample was collected, analyzed and used as FS. Being available, three FO membrane samples were assessed in this part of the study and the best membrane was selected for further investigations. In comparison to HTI’s Cellulose Triacetate (CTA) and Woongjin TFC membranes, Porifera’s commercial membrane proved to be best membrane with respect to baseline flux, where DS was NaCl and FS was DI water. Having the smallest structural parameter (S), internal concentration polarization (ICP) is minimized yielding highest flux. Different concentrations of ammonium sulphate were used as DS using the BGW sample. Like previously, the performance was assessed based on water flux, reverse permeation and feed ions rejection. A logarithmic relation was drawn between water flux and ammonium sulphate concentration. Same relation existed between ammonium sulphate concentration and water flux due to DICP effects. However, in this study, SRSF values did not exceed 0.18 g/l for both NH4+ and SO42- ions, indicating high membrane selectivity. At flux exceeding 20 Lm-2h-1, NH4+ ion reported higher SRSF values than that of SO42− ion.. Again, SRSF came out to be almost constant irrespective of ammonium sulphate concentration. While increasing draw solution concentration lead to increasing Na+ ion rejection, it caused a significant decline in Cl- ion rejection. This phenomenon could be probably associated to an ion exchange mechanism and reversal of membrane surface charge. In conclusion, FDFO is a promising technology that could possibly alleviate the water scarcity problem in Egypt. Not only is FDFO a sustainable desalination technology, but also it has numerous advantages over conventional desalination technologies. Abundant brackish groundwater could be efficiently exploited to produce valuable nutrient-rich irrigation water, being the major fresh water consumer in Egypt. The scheme studied demonstrated that ammonium sulphate is an efficient DS for FDFO process, especially using Porifera’s commercial FO membrane, exhibiting high osmotic pressure, low reverse solute permeation and remarkable rejection of feed solute. The proposed scheme could lead to a technology platform that would supply supplementary irrigation water, reduce soil salinity, manage fertilizer application and close the irrigation – brackish water – drainage vicious loop

A reconfigurable wideband and multiband antenna using dual-patch elements for compact wireless devices

This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 IEEEA reconfigurable wideband and multiband C-Slot patch antenna with dual-patch elements is proposed and studied. It occupies a compact volume of 50 × 50 × 1.57 (3925 mm3), including the ground plane. The antenna can operate in two dual-band modes and a wideband mode from 5 to 7 GHz. Two parallel C-Slots on the patch elements are employed to perturb the surface current paths for excitation of the dual-band and the wideband modes. Two switches, implemented using PIN diodes, are placed on the connecting lines of a simple feed network to the patch elements. Dual-band modes are achieved by switching “ON” either one of the two patch elements, while the wideband mode with an impedance bandwidth of 33.52% is obtained by switching “ON” both patch elements. The frequencies in the dual-band modes can be independently controlled using positions and dimensions of the C-Slots without affecting the wideband mode. The advantage of the proposed antenna is that two dual-band operations and one wideband operation can be achieved using the same dimensions. This overcomes the need for increasing the surface area normally incurred when designing wideband patch antennas. Simulation results are validated experimentally through prototypes. The measured radiation patterns and peak gains show stable responses and are in good agreements. Coupling between the two patch elements plays a major role for achieving the wide bandwidth and the effects of mutual coupling between the patch elements are also studied

Ebola Virus Disease: The Biology, Pathology, Treatments, and Advancements

Ebola virus disease (EVD) is caused by a virulent pathogen, which is a member of the viral family Filoviridae. It is a filamentous viral particle containing a single stranded, negative RNA. It causes extreme fatal hemorrhagic fever in both humans and non-humans. It is mainly found in Africa. Transmission of EVD occurs primarily through contact with infected body fluids. It causes immune suppression that eventually leads to multiple organ failure due to the proliferation. The World Health Organization (WHO) classified the 2013-2016 outbreak and after the current Ebola outbreak on August 1, 2018 in Dominican Republic of Congo (DRC), the outbreak has been considered a “Public Health Emergency of International Concern”. As of December 16, 2019, the DRC Ministry of Health reported 3,348 cases of Ebola from which 2,210 people died, the fatality ratio for this outbreak being as high as 66%. The objective was to investigate the pathology and mechanisms of the virus and current methods that are used in order to tackle and impede the virus with treatments. Current scientific research explores how the -ssRNA is transcribed by VP35, VP30 and RNA dependent RNA polymerase into +ssRNA, which are then translated into proteins in humans. The research also reviewed current treatments, therapies and the ones that are still under development. This research will provide information about the pathological insights for the ongoing epidemic with further information and understanding about the potential development with creative ideas to make the advancements with Ebola treatments to work. As of the current situation there is no cure for Ebola virus. The goal is to make it more understanding amongst the population worldwide

Urban Agriculture and Community Food Security in the United States: Farming from the City Center To the Urban Fringe

Urban Agriculture and Community Food Security in the United States: Farming from the City Center To the Urban Fringe is prepared by the Urban Agriculture Committee of the Community Food Security Coalition to raise awareness of the ways that urban agriculture can respond to food insecurity. The document advocates for policies that promote small-scale urban and peri-urban farming, and thereby prepare the next generation of urban farming leaders

Comparison of frequency and time domain methods of assessment of cerebral autoregulation in traumatic brain injury.

The impulse response (IR)-based autoregulation index (ARI) allows for continuous monitoring of cerebral autoregulation using spontaneous fluctuations of arterial blood pressure (ABP) and cerebral flow velocity (FV). We compared three methods of autoregulation assessment in 288 traumatic brain injury (TBI) patients managed in the Neurocritical Care Unit: (1) IR-based ARI; (2) transfer function (TF) phase, gain, and coherence; and (3) mean flow index (Mx). Autoregulation index was calculated using the TF estimation (Welch method) and classified according to the original Tiecks' model. Mx was calculated as a correlation coefficient between 10-second averages of ABP and FV using a moving 300-second data window. Transfer function phase, gain, and coherence were extracted in the very low frequency (VLF, 0 to 0.05 Hz) and low frequency (LF, 0.05 to 0.15 Hz) bandwidths. We studied the relationship between these parameters and also compared them with patients' Glasgow outcome score. The calculations were performed using both cerebral perfusion pressure (CPP; suffix 'c') as input and ABP (suffix 'a'). The result showed a significant relationship between ARI and Mx when using either ABP (r=-0.38, P<0.001) or CPP (r=-0.404, P<0.001) as input. Transfer function phase and coherence_a were significantly correlated with ARI_a and ARI_c (P<0.05). Only ARI_a, ARI_c, Mx_a, Mx_c, and phase_c were significantly correlated with patients' outcome, with Mx_c showing the strongest association.This is the accepted manuscript. The final version's available from Nature Publishing at http://dx.doi/10.1038/jcbfm.2014.192

Cerebral vasospasm affects arterial critical closing pressure.

The effect of cerebral vasospasm (CVS) after aneurysmal subarachnoid hemorrhage (SAH) on critical closing pressure (CrCP) has not been fully delineated. Using cerebral impedance methodology, we sought to assess the behavior of CrCP during CVS. As CrCP expresses the sum of intracranial pressure (ICP) and vascular wall tension, we also explored its role in reflecting changes in vascular tone occurring in small vessels distal to spasm. This retrospective analysis was performed using recordings from 52 patients, diagnosed with CVS through transcranial Doppler measurements. Critical closing pressure was calculated noninvasively using arterial blood pressure and blood flow velocity. Outcome was assessed at both discharge and 3 months after ictus with the Glasgow Outcome Scale. The onset of CVS caused significant decreases in CrCP (P=0.025), without any observed significant changes in ICP (P=0.134). Vasospasm induced asymmetry, with CrCP ipsilateral to CVS becoming significantly lower than contralateral (P=0.025). Unfavorable outcomes were associated with a significantly lower CrCP after the onset of CVS (discharge: P=0.014; 3 months after SAH: P=0.020). Critical closing pressure is reduced in the presence of CVS in both temporal and spatial assessments. As ICP remained unchanged during CVS, reduced CrCP most probably reflects a lower wall tension in dilated small vessels distal to spasm.GVV is supported by an A.G. Leventis Foundation Scholarship, and a Charter Studentship from St Edmund’s College, Cambridge. AGK is supported by a Royal College of Surgeons of England Research Fellowship, a National Institute for Health Research (NIHR) Academic Clinical Fellowship, and a Raymond and Beverly Sackler Studentship. JD is supported by a Woolf Fisher Trust scholarship. PJH is supported by an NIHR Research Professorship, the NIHR Cambridge Biomedical Research Centre and has been appointed as the Surgical Specialty Lead for Neurosurgery, Royal College of Surgeons of England Clinical Research Initiative. JDP and MC are supported by the NIHR Cambridge Biomedical Research Centre and JDP by NIHR Senior Investigator Award. The prospective study16 on which this retrospective analysis was based, was supported by the National Institute of Health Research, Biomedical Research Centre (Neuroscience Theme). MC was supported by NIHR Cambridge Biomedical Research Centre.This is the accepted manuscript. The final published version is available from Nature Publishing at http://www.nature.com/jcbfm/journal/vaop/ncurrent/full/jcbfm2014198a.html

Baroreflex Impairment After Subarachnoid Hemorrhage Is Associated With Unfavorable Outcome.

BACKGROUND AND PURPOSE: Aneurysmal subarachnoid hemorrhage (SAH) is characterized by important changes in the autonomic nervous system with potentially adverse consequences. The baroreflex has a key role in regulating the autonomic nervous system. Its role in SAH outcome is not known. The purpose of this study was to evaluate the association between the baroreflex and the functional 3-month outcome in SAH. METHODS: The study used a prospective database of 101 patients hospitalized for SAH. We excluded patients receiving β-blockers or noradrenaline. Baroreflex sensitivity (BRS) was measured using the cross-correlation method. A good outcome was defined by a Glasgow Outcome Scale score at 4 or 5 at 3 months. RESULTS: Forty-eight patients were included. Median age was 58 years old (36-76 years); women/men: 34/14. The World Federation of Neurosurgery clinical severity score on admission was 1 or 2 for 73% of patients. In the univariate analysis, BRS (P=0.007), sedation (P=0.001), World Federation of Neurosurgery score (P=0.001), Glasgow score (P=0.002), Fisher score (P=0.022), and heart rate (P=0.037) were associated with outcome. The area under the receiver operating characteristic curve for the model with BRS as a single predictor was estimated at 0.835. For each unit increase in BRS, the odds for a good outcome were predicted to increase by 31%. Area under the receiver operating characteristic curve for heart rate alone was 0.670. In the multivariate analysis, BRS (odds ratio, 1.312; 95% confidence interval, 1.048-1.818; P=0.018) and World Federation of Neurosurgery (odds ratio, 0.382; 95% confidence interval, 0.171-0.706; P=0.001) were significantly associated with outcome. Area under the receiver operating characteristic curve was estimated at 0.900. CONCLUSIONS: In SAH, early BRS was associated with 3-month outcome. This conclusion requires confirmation on a larger number of patients in a multicentre study

Non-Integrated and Integrated On-Board Battery Chargers (iOBCs) for Electric Vehicles (EVs) : A Critical Review

The rising Greenhouse Gas (GHG) emissions stemming from the extensive use of automobiles across the globe represent a critical environmental challenge, contributing significantly to phenomena such as global warming and the deterioration of air quality. To address these challenges, there is a critical need for research and development in electric vehicles (EVs) and their associated charging infrastructure, including off-board and on-board chargers (OBCs). This paper aims to bridge the gaps in existing review literature by offering a comprehensive review of both integrated and non-integrated OBCs for EVs, based on the authors’ knowledge at the time of writing. The paper begins by outlining trends in the EV market, including voltage levels, power ratings, and relevant standards. It then provides a detailed analysis of two-level and multi-level power converter topologies, covering AC-DC power factor correction (PFC) and isolated DC-DC topologies. Subsequently, it discusses single-stage and two-stage non-integrated OBC solutions. Additionally, various categories of integrated OBCs (iOBCs) are explored, accompanied by relevant examples. The paper also includes comparison tables containing technical specifications and key characteristics for reference and analysis

Increased blood glucose is related to disturbed cerebrovascular pressure reactivity after traumatic brain injury.

BACKGROUND: Increased blood glucose and impaired pressure reactivity (PRx) after traumatic brain injury (TBI) are both known to correlate with unfavorable patient outcome. However, the relationship between these two variables is unknown. METHODS: To test the hypothesis that increased blood glucose leads to increased PRx, we retrospectively analyzed data from 86 traumatic brain injured patients admitted to the Neurocritical Care Unit. Data analyzed included arterial glucose concentration, intracranial pressure (ICP), cerebral perfusion pressure (CPP) and end-tidal CO2. PRx was calculated as the moving correlation coefficient between averaged (10 seconds) arterial blood pressure and ICP. One arterial glucose concentration and one time-aligned PRx value were obtained for each patient, during each day until the fifth day after ictus. RESULTS: Mean arterial glucose concentrations during the first 5 days since ictus were positively correlated with mean PRx (Pearson correlation coefficient = 0.25, p = 0.02). The correlation was strongest on the first day after injury (Pearson correlation coefficient = 0.47, p = 0.008). CONCLUSION: Our preliminary findings indicate that increased blood glucose may impair cerebrovascular reactivity, potentially contributing to a mechanistic link between increased blood glucose and poorer outcome after TBI.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s12028-014-0042-

Relationship Between Baroreflex and Cerebral Autoregulation in Patients With Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage.

Introduction: Common consequences following aneurysmal subarachnoid hemorrhage (aSAH) are cerebral vasospasm (CV), impaired cerebral autoregulation (CA), and disturbance in the autonomic nervous system, as indicated by lower baroreflex sensitivity (BRS). The compensatory interaction between BRS and CA has been shown in healthy volunteers and stable pathological conditions such as carotid atherosclerosis. The aim of this study was to investigate whether the inverse correlation between BRS and CA would be lost in patients after aSAH during vasospasm. A secondary objective was to analyze the time-trend of BRS after aSAH. Materials and Methods: Retrospective analysis of prospectively collected data was performed at the Neuro-Critical Care Unit of Addenbrooke's Hospital (Cambridge, UK) between June 2010 and January 2012. The cerebral blood flow velocity (CBFV) was measured in the middle cerebral artery using transcranial Doppler ultrasonography (TCD). The arterial blood pressure (ABP) was monitored invasively through an arterial line. CA was quantified by the correlation coefficient (Mxa) between slow oscillations in ABP and CBFV. BRS was calculated using the sequential cross-correlation method using the ABP signal. Results: A total of 73 patients with aSAH were included. The age [median (lower-upper quartile)] was 58 (50-67). WFNS scale was 2 (1-4) and the modified Fisher scale was 3 (1-3). In the total group, 31 patients (42%) had a CV and 42 (58%) had no CV. ABP and CBFV were higher in patients with CV during vasospasm compared to patients without CV (p = 0.001 and p < 0.001). There was no significant correlation between Mxa and BRS in patients with CV, neither during nor before vasospasm. In patients without CV, a significant, although moderate correlation was found between BRS and Mxa (rS = 0.31; p = 0.040), with higher BRS being associated with worse CA. Multiple linear regression analysis showed a significant worsening of BRS after aSAH in patients with CV (R p = -0.42; p < 0.001). Conclusions: Inverse compensatory correlation between BRS and CA was lost in patients who developed CV after aSAH, both before and during vasospasm. The impact of these findings on the prognosis of aSAH should be investigated in larger studies