A review of flow field characteristics in submerged hollow fiber membrane bioreactor: Micro-interface, module and reactor.

As an important part of the membrane field, hollow fiber membranes (HFM) have been widely concerned by scholars. HFM fouling in the industrial application results in a reduction in its lifespan and an increase in cost. In recent years, various explorations on the HFM fouling control strategies have been carried out. In the current work, we critically review the influence of flow field characteristics in HFM-based bioreactor on membrane fouling control. The flow field characteristics mainly refer to the spatial and temporal variation of the related physical parameters. In the HFM field, the physical parameter mainly refers to the variation characteristics of the shear force, flow velocity and turbulence caused by hydraulics. The factors affecting the flow field characteristics will be discussed from three levels: the micro-flow field near the interface of membrane (micro-interface), the flow field around the membrane module and the reactor design related to flow field, which involves surface morphology, crossflow, aeration, fiber packing density, membrane vibration, structural design and other related parameters. The study of flow field characteristics and influencing factors in the HFM separation process will help to improve the performance of HFM in full-scale water treatment plants.

Progress in membrane distillation processes for dye wastewater treatment: A review.

Textile and cosmetic industries generate large amounts of dye effluents requiring treatment before discharge. This wastewater contains high levels of reactive dyes, low to none-biodegradable materials and chemical residues. Technically, dye wastewater is characterised by high chemical and biological oxygen demand. Biological, physical and pressure-driven membrane processes have been extensively used in textile wastewater treatment plants. However, these technologies are characterised by process complexity and are often costly. Also, process efficiency is not achieved in cost-effective biochemical and physical treatment processes. Membrane distillation (MD) emerged as a promising technology harnessing challenges faced by pressure-driven membrane processes. To ensure high cost-effectiveness, the MD can be operated by solar energy or low-grade waste heat. Herein, the MD purification of dye wastewater is comprehensively and yet concisely discussed. This involved research advancement in MD processes towards removal of dyes from industrial effluents. Also, challenges faced by this process with a specific focus on fouling are reviewed. Current literature mainly tested MD setups in the laboratory scale suggesting a deep need of further optimization of membrane and module designs in near future, especially for textile wastewater treatment. There is a need to deliver customized high-porosity hydrophobic membrane design with the appropriate thickness and module configuration to reduce concentration and temperature polarization (CP and TP). Also, energy loss should be minimized while increasing dye rejection and permeate flux. Although laboratory experiments remain pivotal in optimizing the MD process for treating dye wastewater, the nature of their time intensity poses a challenge. Given the multitude of parameters involved in MD process optimization, artificial intelligence (AI) methodologies present a promising avenue for assistance. Thus, AI-driven algorithms have the potential to enhance overall process efficiency, cutting down on time, fine-tuning parameters, and driving cost reductions. However, achieving an optimal balance between efficiency enhancements and financial outlays is a complex process. Finally, this paper suggests a research direction for the development of effective synthetic and natural dye removal from industrially discharged wastewater.

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. Experimental and computational analyses were employed to compare the performance of CHF and the conventional design. The CHF module design successfully mitigates the TP effect in HF DCMD, increasing the flux by 148 % and 163 % in cross-flow and localized heating (LH) modes, respectively. Moreover, CHF operated in LH mode exhibits the lowest energy consumption of all configurations (81 % decrease) compared to the conventional design. This novel module design represents a new pathway for efficient and highly performing DCMD module.

Gas Separation Membrane Module Modeling: A Comprehensive Review.

Membrane gas separation processes have been developed for diverse gas separation applications that include nitrogen production from air and CO2 capture from point sources. Membrane process design requires the development of stable and robust mathematical models that can accurately quantify the performance of the membrane modules used in the process. The literature related to modeling membrane gas separation modules and model use in membrane gas separation process simulators is reviewed in this paper. A membrane-module-modeling checklist is proposed to guide modeling efforts for the research and development of new gas separation membranes.

pH and Design on n-Alkyl Alcohol Bulk Liquid Membranes for Improving Phenol Derivative Transport and Separation.

Regardless of the type of liquid membrane (LM) (Bulk Liquid Membranes (BLM), Supported Liquid Membranes (SLM) or Emulsion Liquid Membranes (ELM)), transport and separation of chemical species are conditioned by the operational (OP) and constructive design parameters (DP) of the permeation module. In the present study, the pH of the aqueous source phase (SP) and receiving phase (RP) of the proposed membrane system were selected as operational parameters. The mode of contacting the phases was chosen as the convective transport generator. The experiments used BLM-type membranes with spheres in free rotation as film contact elements of the aqueous phases with the membrane. The target chemical species were selected in the range of phenol derivatives (PD), 4−nitrophenol (NP), 2,4−dichlorophenol (DCP) and 2,4−dinitrophenol (DNP), all being substances of technical-economic and environmental interest. Due to their acid character, they allow the evaluation of the influence of pH as a determining operational parameter of transport and separation through a membrane consisting of n−octanol or n−decanol (n−AlcM). The comparative study performed for the transport of 4−nitrophenol (NP) showed that the module based on spheres (Ms) was more performant than the one with phase dispersion under the form of droplets (Md). The sphere material influenced the transport of 4−nitrophenol (NP). The transport module with glass spheres (Gl) was superior to the one using copper spheres (Cu), but especially with the one with steel spheres (St). In all the studied cases, the sphere-based module (Ms) had superior transport results compared to the module with droplets (Md). The extraction efficiency (EE) and the transport of 2,4−dichlorophenol (DCP) and 2,4−dinitrophenol (DNP), studied in the module with glass spheres, showed that the two phenolic derivatives could be separated by adjusting the pH of the source phase. At the acidic pH of the source phase (pH = 2), the two derivatives were extracted with good results (EE > 90%), while for pH values ranging from 4 to 6, they could be separated, with DCP having doubled separation efficiency compared to DNP. At a pH of 8 in the source phase, the extraction efficiency halved for both phenolic compounds.

Design and Implementation of Intelligent Learning System Based on Big Data and Artificial Intelligence.

In order to improve the level of education development in remote areas of China, help minority schools to better play the advantages of multimedia network teaching resources provided by the state, and further improve the level of multimedia network management, a multimedia network teaching management system is studied and developed. The teaching information and business process of the school is analyzed, the division of the structure of the film and television multimedia information management system is completed, and the overall structure, functional structure, and database of the system are designed; Tornado technology, NoSQL database technology, jQuery technology, and Ajax technology are used to complete the development of the system. The results show that the real system can provide a highly automated platform for the school multimedia network-teaching management. The system makes the teaching staff work more efficiently and accurately. The results show that the system studied has a significant effect on the multimedia teaching of minority films and television. Using the characteristics of the combination of pictures, text, sound, image, and shadow, the knowledge can be shown to students intuitively, which is helpful to relaxed and happy learning of students and stimulate their desire to learn. Multimedia teaching has become an important teaching assistant tool. This exploration can provide theoretical support for the design of the network teaching information management system based on artificial intelligence, decentralize the complex network environment, and carry out decentralized management.

The emerging role of 3D printing in water desalination.

Unmatched flexibility in terms of material selection, design and scalability, along with gradually decreasing cost, has led 3D printing to gain significant attention in various water treatment and desalination applications. In desalination, 3D printing has been applied to improve the energy efficiency of existing technologies. For thermal desalination, this involves the use of 3D printed components that enhance water evaporation and energy harvesting with new materials and designs. For membrane-based desalination, 3D printing offers membranes and other module components with customized materials and geometries for better fouling resistance and productivity. This review highlights the current status, advances and challenges associated with 3D printing in both thermal and membrane-based desalination technologies. Other unique benefits offered by 3D printing for water desalination along with the associated challenges are also discussed in this review. Finally, the future prospects and research directions are highlighted related to the application of 3D printing in the water desalination industry.

Submerged Osmotic Processes: Design and Operation to Mitigate Mass Transfer Limitations.

Submerged forward osmosis (FO) is of high interest for bioreactors, such as osmotic membrane bioreactor, microalgae photobioreactor, food or bioproduct concentration where pumping through pressurized modules is a limitation due to viscosity or breakage of fragile components. However, so far, most FO efforts have been put towards cross flow configurations. This study provides, for the first time, insights on mass transfer limitations in the operation of submerged osmotic systems and offer recommendations for optimized design and operation. It is demonstrated that operation of the submerged plate and frame FO module requires draw circulation in the vacuum mode (vacuum assisted osmosis) that is in favor of the permeation flux. However, high pressure drops and dead zones occurring in classical U-shape FO draw channel strongly disadvantage this design; straight channel design proves to be more effective. External concentration polarization (ECP) is also a crucial element in the submerged FO process since mixing of the feed solution is not as optimized as in the cross flow module unless applying intense stirring. Among the mitigation techniques tested, air scouring proves to be more efficient than feed solution circulation. However, ECP mitigation methodology has to be adapted to application specificities with regards to combined/synergetic effects with fouling mitigation.

A novel multi-stage direct contact membrane distillation module: Design, experimental and theoretical approaches.

An economic desalination system with a small scale and footprint for remote areas, which have a limited and inadequate water supply, insufficient water treatment and low infrastructure, is strongly demanded in the desalination markets. Here, a direct contact membrane distillation (DCMD) process has the simplest configuration and potentially the highest permeate flux among all of the possible MD processes. This process can also be easily instituted in a multi-stage manner for enhanced compactness, productivity, versatility and cost-effectiveness. In this study, an innovative, multi-stage, DCMD module under countercurrent-flow configuration is first designed and then investigate both theoretically and experimentally to identify its feasibility and operability for desalination application. Model predictions and measured data for mean permeate flux are compared and shown to be in good agreement. The effect of the number of module stages on the mean permeate flux, performance ratio and daily water production of the MDCMD system has been theoretically identified at inlet feed and permeate flow rates of 1.5 l/min and inlet feed and permeate temperatures of 70 °C and 25 °C, respectively. The daily water production of a three-stage DCMD module with a membrane area of 0.01 m2 at each stage is found to be 21.5 kg.

Design of online course platform and its implementation in Peking Union Medical College / 中华医学图书情报杂志

Online teaching has recently become a new way in medical education, to which great importance has been attached by domestic educational circles. The design principles, overall framework and functional structure of the online course platform in Peking Medical College were thus described with its implementation and characteristics summarized in the hope of providing certain reference for its building in domestic medical colleges and universities.

Design and Implementation of Malignant Tumor Main Diagnosis ICD Selection Module / 医学信息学杂志

〔Abstract〕 The paper elaborates the devolopment background of malignant tumor main diagnosis ICD selection module, embeds this module into Electronic Medical Records ( EMR) ystem, introduces design basis, principles and ideas, analyzes the operation process and module functions.It also points out that this module could assist doctors to fill in the diagnostic information of malignant tumor pa-tients, provide better services for clinical, scientific research and management through examples.

Influence of crestal module design on marginal bone stress around dental implant / 대한치과보철학회지

PURPOSE: This study was to investigate how the crestal module design could affect the level of marginal bone stress around dental implant. MATERIALS AND METHODS: A submerged implant of 4.1 mm in diameter and 10 mm in length was selected as baseline model (Dentis Co., Daegu,Korea).A total of 5 experimental implants of different crestal modules were designed (Type I model : with microthread at the cervical 3 mm, Type II model : the same thread pattern as Type I but with a trans-gingival module, Type III model: the same thread pattern as the control model but with a trans-gingival module, Type IV model: one piece system with concave transgingival part, Type V model: equipped with beveled platform). Stress analysis was conducted with the use of axisy mmetric finite element modeling scheme. A force of 100 N was applied at 30 degrees from the implant axis. RESULTS: Stress analysis has shown no stress concentration around the marginal bone for the control model. As compared to the control model, the stress levels of 0.2 mm areas away from the recorded implant were slightly lower in Type I and Type IV models, but higher in Type II, Type III and Type V models. As compared to 15.09 MPa around for the control model, the stress levels were 14.78 MPa, 18.39 MPa, 21.11 MPa, 14.63 MPa, 17.88 MPa in the cases of Type I, II, III, IV and V models. CONCLUSION: From these results, the conclusion was drawn that the microthread and the concavity with either crestal or trans-gingival modules maybe used in standard size dental implants to reduce marginal bone stress.

Comparison of Crestal Bone Loss along Two Implant Crest Module Designs.

BACKGROUND: Crestal bone loss along the dental implant surface deranges its prognosis and is known to occur with implants having 02 mm smooth crest module/collar design. Implants with rough coated crest module/collar design are said to reduce crestal bone loss. Comparison of crestal bone loss with both crest module/collar designs of implants needs to be done. METHODS: Twenty cases were selected. Each case received one implant with smooth collar design (Group-A) and one implant with coated rough collar design (Group-B). All the 40 implants were prosthetically loaded after a healing period of six months. Crestal bone loss was measured on mesial, distal, buccal and lingual side of each implant using maxillofacial computed tomography at six, twelve and eighteen months time interval after placing the implants. Soft tissue evaluation was carried out around each implant using Gingival, Plaque and Calculus Indices, six and twelve months after loading the implants. RESULT: After 18 months i.e. one year after loading the implants, Group-A implants showed an overall average crestal bone loss of 1.53 mm and Group-B implants showed average bone loss of 1.42 mm, the difference being statistically significant (p < 0.05). For both types of implants, average crestal bone loss was maximum on the buccal side, followed by mesial, lingual and distal sides. Soft tissue evaluation revealed that the tissues remained healthy till the end of study for both types of implants. CONCLUSION: Crestal bone loss was less among implants with rough collar design as compared to smooth collar design.

Cervical design effect of dental implant on stress distribution in crestal cortical bone studied by finite element analysis / 대한치과보철학회지

STATEMENT OF PROBLEM: High stress concentration on the crestal cortical bone has been regraded as a major etiologic factor jeopardizing long term stability of endosseous implants. PURPOSE: To investigate if the design characteristics of crestal module, i.e. internal type, external type, and submerged type, affect stress distribution on the crestal cortical bone. MATERIAL AND METHODS: A cylindrical shaped implant, 4.3 mm in diameter and 10 mm in length, with 3 different crestal modules, i.e. internal type, external type, and submerged type, were analysed. An axisymmetric scheme was used for finite elment formulation. A vertical load of 50 N and an oblique load of 50 N acting at 45degrees with the implant's long axis was applied. The peak crestal bone stress acting at the intersection of implant and crestal bone was compared. RESULTS: Under vertical load, the crestal bone stress was high in the order of internal, external, and submerged types. Under the oblique loading condition, it was in the order of internal, submerged, and external types. CONCLUSION: Crestal module design was found to affect the level of the crestal bone stresses although the actual amount was not significant.

The module design of pharmaceutical superfine pulverization matched up GMP / 中成药

The module design of pharmaceutical superfine pulverization matched up GMP was attempted. The integral of mechanism and electricity into the whole pulverization process was designed and established.