Hydrodynamics study of the modified rotating disc contactor for CO2 absorption from natural gas using emulsion liquid membrane

This study modified the rotating disc contactor (RDC) structure to optimize its performance for CO2 separation from natural gas feed using stable emulsion liquid membrane (ELM). Based on parametric study of absorption of CO2 from natural gas feed into ELM, the mass transfer behavior in the RDC system was optimized. Rotor diameter, stator inner diameter, and minimum free area of RDC were modified to achieve maximum contact between dispersed liquid phase and gas feed phase, which was necessary to achieve maximum mass transfer. The problem of rupture of the emulsion droplet due to pressure created by direct dispersion of gas at the bottom of conventional RDC extraction system was addressed by adding an impeller at the bottom compartment of RDC. The impeller provided continuous mixing of emulsion and a gas sparger was fitted along the impeller's side that maintained the dispersed aqueous phase miscible in system. The hydrodynamic behavior of a modified RDC was optimized for CO2 absorption from natural gas in ELM, which indicated that modified design dimensions can provide a maximum liquid-gas contact. Beside the concentration of CO2 in natural gas feed, it was observed that the speed of RDC and run time significantly influence CO2 absorption from natural gas using ELM. When all the parameters optimized for CO2 absorption from natural gas feed this study is useful in extending the application of RDC in liquid-gas system. In this study, the use of ELM in RDC can be effective for CO2 when applied under proper conditions

Efficient Removal of Chromium and Lead from Tanneries Effluent of Korangi Industrial Area Karachi Using Rotating Disk Mesh as Anode Electrode Electrocoagulation

The aim of this study was to examine the best electrode design for the electrocoagulation process with the best removal performance, reduced passivation on the electrode surface, and lower energy consumption requirements for removing Chromium (Cr) and Lead (Pb) from leather tannery effluent. Three different electrodes were compared: non-rotating disk electrode (NRDE), rotating disk electrode (RDE) and rotating disk mesh electrode (RDME). All electrodes were used to observe a reduction in passivation on the electrode surface and its effects on the removal performance of Cr and Pb. The material used for the electrodes was iron. The maximum removal efficiency obtained was Cr = 87.9% and Pb = 97.5% under the following operating conditions: pH = 7, treatment time = 90 min, current density = 6.57 mA/cm², and RPM = 80. The results show that the electrical energy requirement for treating chromium and lead using RDME was 4.5 kWh/m³, which was found to be lower than the energy requirement observed in various other studies for treating tannery effluent. According to the results, RDME shows the highest removal performance with lower specific energy consumption compared to NRDE and RDE. RDME can be efficiently employed at a larger scale for treating leather tannery effluent

Innovative method to prepare a stable emulsion liquid membrane for high CO2 absorption and its performance evaluation for a natural gas feed in a rotating disk contactor

This paper presents an innovative method to prepare a stable emulsion liquid membrane (ELM) for high CO2 absorption in a natural gas feed. This new method achieved high throughput at low power consumption. The ELM prepared using this new method was characterized by determining the effects of the concentration of the ELM constituents, emulsification time, and speed on the emulsion droplet size (EDS) and stability. This was followed by a parametric study of the process parameters for CO2 separation from natural gas in a rotating disk contactor (RDC)-based setup to evaluate the performance of a stable ELM. The results suggest that the retention time of the stable ELM in a RDC increases with increasing amount of absorbed CO2. The results support the fundamental development of the ELM process to achieve a high overall separation efficiency of CO2 removal from natural gas with a relatively small contact time. This is the first parametric study of CO2 absorption from a gas stream in ELM using a RDC as the contracting equipment. The results of the parametric study suggested that the factors of time, TEA concentration and RDC speed have significant effect on the CO2 absorption from natural gas feed. It was identified that 4% TEA in ELM, 30 min operational time and 700 rpm speed of modified RDC system is suitable for maximum CO2 absorption from gas mixture of CO2/CH4. Furthermore, the study suggested that the ELM containing 4% TEA can absorb 5.6 kmol/m3 CO2

Architectural Design and Prototyping of Co-PPGIS: A Groupware-Based Online Synchronous Collaborative PPGIS to Support Municipality Development and Planning Management Workflows

Co-PPGIS has a wide variety of applications like municipal planning, emergency response, public health and security, etc. The main focus of this chapter is on the development and design of a Web Collaborative PPGIS (Co-PPGIS) infrastructure. As part of municipality’s planning and management services, Co-PPGIS is developed for real-time map sharing application system. Co-PPGIS is an effective and essential online meeting system for supporting group collaborations on geographic information such as maps and imageries, and capturing and sharing of local/domain knowledge in real time. Co-PPGIS permits amalgamation of geospatial data and collaborator’s input in the form of geo-referenced notations. It incorporates coherent components as map sharing, real-time chat, video conferencing, geo-referenced textual and graphical notations. The study aims to focus on public participation and geo-collaboration facilitated with information sharing, interactive geo-conferencing, real-time map, and data sharing with tools to draw features or add annotation to the map while discussions, uploading documents, and live communication. Co-PPGIS provides an efficient and reliable platform that will significantly reduce the time to acquire, process, and analyze data. The significance of this study is to contribute to existing public participation practices, to municipal planning, to decision-making, or to geographic information science

Clinical and electrophysiological efficacy of leaf extract of Gingko biloba L (Ginkgoaceae) in subjects with diabetic sensorimotor polyneuropathy

Purpose: To investigate the health benefits of Gingko biloba L. leave extract EGb 761 in patients with diabetic sensorimotor polyneuropathy (DSP).Method: In a randomized, double-blind, placebo trial, patients (n = 156) received Gingko biloba (120 mg/day) or placebo for 6 months. Efficacy of Gingko biloba extract EGb 761 was assessed on the reduction in the scores of “Short-Form McGill Pain Questionnaire” (SF-MPQ) and improvements in latency, amplitude and conduction velocity of four sensory (ulnar, median, peroneal and sural) and four motor (ulnar, median, peroneal and tibial) nerves.Results: Gingko biloba significantly improved the mean scores of sensory, affective, visual analogue score (VAS) and present pain intensity (PPI) of SF-MPQ on 3 and 6 month post-treatment. At the start of experiment in the Gingko biloba-treated group, scores for sensory, affective, VAS and PPI domains were 12.90 ± 7.21, 4.40 ± 1.79, 4.38 ± 1.69 and 3.24 ± 0.78 respectively. After 6-months treatment with Gingko biloba, scores for sensory, affective, VAS and PPI domains were reduced (p < 0.01) to 7.24 ± 4.91, 3.11 ± 1.81, 3.37 ± 1.35 and 2.45 ± 0.65 respectively. Contrarily, in the placebo-administered group, sensory domain was (p < 0.01) deteriorated after 6 month (4.70 ± 1.87) compared to the baseline (4.04 ± 1.67). Gingko biloba extract EGb 761 failed to influence the electrophysiological measures when compared with the placebo group. The common adverse effects observed with Gingko biloba were somnolence and dryness of mouth compared with the placebo-treated patientsConclusion: Gingko biloba extract EGb 761 seems to be an effective and safe drug for reducing symptoms of DSP without any apparent effect on the electrophysiological attributes of sensorimotor nerves.Keywords: Diabetic polyneuropathy, Diabetes mellitus, Electrophysiological parameters, Gingko biloba, Sensorimotor nerves, Short-Form McGill Pain Questionnair

Effect of early tranexamic acid administration on mortality, hysterectomy, and other morbidities in women with post-partum haemorrhage (WOMAN): an international, randomised, double-blind, placebo-controlled trial

Background Post-partum haemorrhage is the leading cause of maternal death worldwide. Early administration of tranexamic acid reduces deaths due to bleeding in trauma patients. We aimed to assess the effects of early administration of tranexamic acid on death, hysterectomy, and other relevant outcomes in women with post-partum haemorrhage. Methods In this randomised, double-blind, placebo-controlled trial, we recruited women aged 16 years and older with a clinical diagnosis of post-partum haemorrhage after a vaginal birth or caesarean section from 193 hospitals in 21 countries. We randomly assigned women to receive either 1 g intravenous tranexamic acid or matching placebo in addition to usual care. If bleeding continued after 30 min, or stopped and restarted within 24 h of the first dose, a second dose of 1 g of tranexamic acid or placebo could be given. Patients were assigned by selection of a numbered treatment pack from a box containing eight numbered packs that were identical apart from the pack number. Participants, care givers, and those assessing outcomes were masked to allocation. We originally planned to enrol 15 000 women with a composite primary endpoint of death from all-causes or hysterectomy within 42 days of giving birth. However, during the trial it became apparent that the decision to conduct a hysterectomy was often made at the same time as randomisation. Although tranexamic acid could influence the risk of death in these cases, it could not affect the risk of hysterectomy. We therefore increased the sample size from 15 000 to 20 000 women in order to estimate the effect of tranexamic acid on the risk of death from post-partum haemorrhage. All analyses were done on an intention-to-treat basis. This trial is registered with ISRCTN76912190 (Dec 8, 2008); ClinicalTrials.gov, number NCT00872469; and PACTR201007000192283. Findings Between March, 2010, and April, 2016, 20 060 women were enrolled and randomly assigned to receive tranexamic acid (n=10 051) or placebo (n=10 009), of whom 10 036 and 9985, respectively, were included in the analysis. Death due to bleeding was significantly reduced in women given tranexamic acid (155 [1·5%] of 10 036 patients vs 191 [1·9%] of 9985 in the placebo group, risk ratio [RR] 0·81, 95% CI 0·65–1·00; p=0·045), especially in women given treatment within 3 h of giving birth (89 [1·2%] in the tranexamic acid group vs 127 [1·7%] in the placebo group, RR 0·69, 95% CI 0·52–0·91; p=0·008). All other causes of death did not differ significantly by group. Hysterectomy was not reduced with tranexamic acid (358 [3·6%] patients in the tranexamic acid group vs 351 [3·5%] in the placebo group, RR 1·02, 95% CI 0·88–1·07; p=0·84). The composite primary endpoint of death from all causes or hysterectomy was not reduced with tranexamic acid (534 [5·3%] deaths or hysterectomies in the tranexamic acid group vs 546 [5·5%] in the placebo group, RR 0·97, 95% CI 0·87-1·09; p=0·65). Adverse events (including thromboembolic events) did not differ significantly in the tranexamic acid versus placebo group. Interpretation Tranexamic acid reduces death due to bleeding in women with post-partum haemorrhage with no adverse effects. When used as a treatment for postpartum haemorrhage, tranexamic acid should be given as soon as possible after bleeding onset. Funding London School of Hygiene & Tropical Medicine, Pfizer, UK Department of Health, Wellcome Trust, and Bill & Melinda Gates Foundation

Polymeric membrane used in natural gas processing to separate carbon dioxide: the facing problems and solutions

For the last two decades polymeric membranes have been used in several gas separation processes. For the high selectivity and permeability various types of membranes have been developed. Thin layers to high dense and hollow fiber to asymmetric wounded materials to determine the effective separation of CO2 from CH4 were used. Ideal membrane materials must have provisions of durability, chemical and thermal resistance, effective separation and economical production and operation. In this review it is observed that most of the polymeric materials face plasticization problem in the separation of CO2 from CH4. This is due to the condensable nature of carbon dioxide that causes swelling in most of the polymeric membranes due to which the efficiency of selectivity and permeability is affected. Most extensive works have been carried out in developing the chemical structure and compositions of polymeric materials to improve the separation properties. Cross-linking and blending of molecular sieving called “mixed-matrix” are the most useful approaches applied in this regard, but no where it is found to be fully effective and ideal polymeric membranes commercially fit to replace the existing systems of CO2 separation from the natural gas. Still area is open to work on to produce more worth full materials and switch towards liquid membranes and hybrid systems

A Combined CFD-Response Surface Methodology Approach for Simulation and Optimization of Arsenic Removal in a Fixed Bed Adsorption Column

An experimentally validated CFD model was developed for lab-scale arsenic (As) fixed-bed columns using COMSOL Multiphysics. The effects of key factors such as the adsorbent bed depth, the feed flow rate, and the initial As concentration (conc.) on the overall As removal performance were investigated. Subsequently, the CFD was combined with response surface methodology (RSM) to optimize process conditions and examine main and interaction effects of these factors on model responses, i.e., the As removal efficiency and the bed saturation time. The ANOVA results suggested that quadratic regression models were highly significant for both responses. The established regression model equations predicted the response values closer to CFD measurements. It was found that, compared with the initial As conc. and the feed flow rate, the effect of the bed depth was more significant. Moreover, both the As removal efficiency and the bed saturation time were increased reasonably with the increasing bed depth and decreased with the increasing feed flow rate and initial As conc. The optimum conditions for the As removal process were obtained as the bed height of 80 cm, the initial As concentration of 2.7 mmol/m3, and the feed flow rate of 1 L/min. The present combined CFD−RSM approach is a useful guideline in overall design and optimization of various lab-scale and industrial applications for removal of As from wastewater