Novel coiled hollow fiber module for high-performance membrane distillation.

Membrane distillation (MD) scale-up is challenged by ineffective heat recovery and the temperature polarization effect. Direct contact membrane distillation (DCMD) modules suffer high thermal conduction losses due to feed flow direction along the length of the membrane, resulting in low thermal efficiency. We propose a novel module design named coiled hollow fiber (CHF) to decouple the flow direction from the membrane surface in hollow fiber (HF) DCMD.

Airfoil-shaped filament feed spacer for improved filtration performance in water treatment.

Optimal spacer design enhances the filtration performance in spiral-wound modules by controlling the local hydrodynamics inside the filtration channel. A novel airfoil feed spacer design fabricated using 3D-printing technology is proposed in this study. The design is a ladder-shaped configuration with primary airfoil-shaped filaments facing the incoming feed flow.

Bioengineering Progress in Lung Assist Devices.

Artificial lung technology is advancing at a startling rate raising hopes that it would better serve the needs of those requiring respiratory support. Whether to assist the healing of an injured lung, support patients to lung transplantation, or to entirely replace native lung function, safe and effective artificial lungs are sought. After 200 years of bioengineering progress, artificial lungs are closer than ever before to meet this demand which has risen exponentially due to the COVID-19 crisis.

Novel hole-pillar spacer design for improved hydrodynamics and biofouling mitigation in membrane filtration.

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.

Hole-Type Spacers for More Stable Shale Gas-Produced Water Treatment by Forward Osmosis.

An appropriate spacer design helps in minimizing membrane fouling which remains the major obstacle in forward osmosis (FO) systems. In the present study, the performance of a hole-type spacer (having holes at the filament intersections) was evaluated in a FO system and compared to a standard spacer design (without holes). The hole-type spacer exhibited slightly higher water flux and reverse solute flux (RSF) when Milli-Q water was used as feed solution and varied sodium chloride concentrations as draw solution.

Effect of localized hydrodynamics on biofilm attachment and growth in a cross-flow filtration channel.

Biofilm attachment and growth in membrane filtration systems are considerably influenced by the localized flow inside the feed channel. The present work aims to map the biofilm attachment/growth mechanism under varying flow conditions. Effect of varying clearance region (space between the spacer filament and membrane surface) on biofouling pattern is investigated by using three 3D-printed pillar spacers having different filament diameters of 340, 500, and 1000 µm while maintaining the same pillar orientation, diameter and height.

Energy efficient 3D printed column type feed spacer for membrane filtration.

Modification of the feed spacer design significantly influences the energy consumption of membrane filtration processes. This study developed a novel column type feed spacer with the aim to reduce the specific energy consumption (SEC) of the membrane based water filtration system. The proposed spacer increases the clearance between the filament and the membrane (reducing the spacer filament diameter) while keeping the same flow channel thickness as compared to a standard non-woven symmetric spacer.

Fouling resilient perforated feed spacers for membrane filtration.

The improvement of feed spacers with optimal geometry remains a key challenge for spiral-wound membrane systems in water treatment due to their impact on the hydrodynamic performance and fouling development. In this work, novel spacer designs are proposed by intrinsically modifying cylindrical filaments through perforations. Three symmetric perforated spacers (1-Hole, 2-Hole, and 3-Hole) were in-house 3D-printed and experimentally evaluated in terms of permeate flux, feed channel pressure drop and membrane fouling.

Infrarenal abdominal aortic aneurysm repair: detection and treatment of associated carotid and coronary lesions.

Management of carotid or coronary lesions associated with abdominal aortic aneurysm (AAA) remains controversial. To determine the influence of these lesions on the outcome of elective infrarenal AAA repair, we review our experience between January 1978 and December 1992. A total of 345 consecutive patients underwent infrarenal AAA repair.

Post traumatic tracheobronchial lesions. A follow-up study of 47 cases.

This report concerns 47 ruptures of the tracheo-bronchial tree from the tracheal origin to the division of the lobar bronchi (trachea in 30 patients, main bronchus in 11, intermediate or lobar bronchus in 6). The disruption was circumferential in 24 cases and non-circumferential in 23. Injuries resulted from crush or blunt trauma in 35 cases, from seat belt or rope strangulation in 8 cases and in 4 cases, lesions were discovered following the tracheal intubation.