scholarly journals Modeling nutrient consumptions in large flow-through bioreactors for tissue engineering

2009 ◽  
Vol 103 (5) ◽  
pp. 1003-1015 ◽  
Author(s):  
Mamatha Devarapalli ◽  
Benjamin J. Lawrence ◽  
Sundararajan V. Madihally
Keyword(s):  
Tissue Engineering ◽  
Flow Through ◽  
Large Flow

scholarly journals Control Method of Slipstream Gas Source System of a Propeller

2019 ◽  
Vol 267 ◽  
pp. 01001
Author(s):  
Jinchun Shi
Keyword(s):  
Control Method ◽  
Low Flow ◽  
Source Control ◽  
Whole Process ◽  
Gas Source ◽  
Compressed Gas ◽  
Flow Through ◽  
Great Energy ◽  
Large Flow ◽  
Stable Control

For the slipstream gas source control system of propeller, there is no mature application in China. The traditional slipstream gas source system manually realizes the stable control of gas and flow through the self-operated pressure reducing device. But this mode can only be used in the condition of small pressure and low flow, cannot meet the actual need of high pressure and large flow, and cannot monitor and automatically control the energy consumption of compressed gas and heating equipment, resulting in great energy waste. Based on the actual engineering conditions, and according to the characteristics, user requirements and work flow of the slipstream gas source system, this paper describes a new control method for the slipstream gas source system of a propeller in detail, which solves the issue of automatic control in the whole process and realizes the key technical point, rapid stabilizing of airflow pressure and temperature.

scholarly journals Hydrodynamics of the Bio-Gripper: A Fluid-Driven “Claw Machine” for Soft Microtissue Translocation

2018 ◽  
Vol 23 (6) ◽  
pp. 540-549
Author(s):  
Francis R. Cui ◽  
Blanche C. Ip ◽  
Jeffrey R. Morgan ◽  
Anubhav Tripathi
Keyword(s):  
Tissue Engineering ◽  
Lift Force ◽  
Solid Organ ◽  
Membrane Flow ◽  
Technological Advances ◽  
Porous Surfaces ◽  
Organ Tissue ◽  
Flow Through ◽  
Living Objects ◽  
Transport Method

Technological advances in solid organ tissue engineering that rely on the assembly of small tissue-building parts require a novel transport method suited for soft, deformable, living objects of submillimeter- to centimeter-length scale. We describe a technology that utilizes membrane flow through a gripper to generate optimized pressure differentials across the top and bottom surfaces of microtissue so that the part may be gripped and lifted. The flow and geometry parameters are developed for automation by analyzing the fluid mechanics framework by which a gripper can lift tissue parts off solid and porous surfaces. For the axisymmetric part and gripper geometries, we examine the lift force on the part as a function of various parameters related to the gripper design, its operation, and the tissue parts and environments with which it operates. We believe our bio-gripping model can be used in various applications in high-throughput tissue engineering.

Laser-based bioprinting for multilayer cell patterning in tissue engineering and cancer research

2021 ◽  
Author(s):  
Haowei Yang ◽  
Kai-Hung Yang ◽  
Roger J. Narayan ◽  
Shaohua Ma
Keyword(s):  
Tissue Engineering ◽  
Cell Damage ◽  
Disease Model ◽  
Functional Materials ◽  
Laser Source ◽  
Cancer Models ◽  
Challenges And Opportunities ◽  
Potential Applications ◽  
Flow Through

Abstract 3D printing, or additive manufacturing, is a process for patterning functional materials based on the digital 3D model. A bioink that contains cells, growth factors, and biomaterials are utilized for assisting cells to develop into tissues and organs. As a promising technique in regenerative medicine, many kinds of bioprinting platforms have been utilized, including extrusion-based bioprinting, inkjet bioprinting, and laser-based bioprinting. Laser-based bioprinting, a kind of bioprinting technology using the laser as the energy source, has advantages over other methods. Compared with inkjet bioprinting and extrusion-based bioprinting, laser-based bioprinting is nozzle-free, which makes it a valid tool that can adapt to the viscosity of the bioink; the cell viability is also improved because of elimination of nozzle, which could cause cell damage when the bioinks flow through a nozzle. Accurate tuning of the laser source and bioink may provide a higher resolution for reconstruction of tissue that may be transplanted used as an in vitro disease model. Here, we introduce the mechanism of this technology and the essential factors in the process of laser-based bioprinting. Then, the most potential applications are listed, including tissue engineering and cancer models. Finally, we present the challenges and opportunities faced by laser-based bioprinting.

Air-Vapor Dynamics in Large-Scale Atmospheric Spray Cooling Systems

1978 ◽  
Vol 100 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Sushil Chaturvedi ◽  
R. W. Porter
Keyword(s):  
Reasonable Agreement ◽  
Large Scale ◽  
Spray Cooling ◽  
Cooling Towers ◽  
Cooling Systems ◽  
Flow Through ◽  
Spray Field ◽  
Large Flow ◽  
Essential Problem ◽  
Theory And Experiments

Atmospheric spray cooling systems are alternatives to cooling towers and cooling ponds. A quantity NTU containing the spray drop-wise parameters allows prediction of cooling range if local wet-bulb temperature is known. The essential problem is predicting local wet-bulb proceeding windward through the spray field. Theory was developed for this purpose involving wind attenuation and turbulent diffusion. Experiments were performed on a large flow-through spray canal involving segments with two types of floating spray modules. Previous experimental data are available for a fixed manifolded spray pond. A comparison of theory and experiments shows reasonable agreement.

scholarly journals Importance of Runoff and Winter Anoxia to the P and N Dynamics of a Beaver Pond

1993 ◽  
Vol 50 (10) ◽  
pp. 2222-2234 ◽  
Author(s):  
Kevin J. Devito ◽  
Peter J. Dillon
Keyword(s):  
Pond Water ◽  
Organic N ◽  
Beaver Pond ◽  
Average Water Temperature ◽  
N Dynamics ◽  
Average Water ◽  
Flow Through ◽  
Large Flow ◽  
Net Release

Annual retentions of total phosphorus (TP) (−11%) and total nitrogen (TN) (−5%) of a headwater beaver pond in central Ontario were low during 1987–88. Annually, inputs exceeded outputs of total reactive P (71%) and NO3–N (35%), and outputs exceeded inputs of total unreactive P (−33%) and total organic N (−26%), and inputs approximated outputs of NH4–N (−8%). Seasonal trends in P and N retention were inversely correlated with runoff. Monthly retention was weakly positively related to average water temperature and redox potential (ORP). Positive monthly retention coincided with low runoff and high biotic assimilation during the growing season. Winter ice cover was associated with undetectable dissolved oxygen and low ORP and increased levels of P and N, particularly NH4–N. High levels of P and N in the surface water during winter were coupled with increased runoff and potentially low biotic assimilation resulting in a net release of TP and TN. Large flow-through of waterborne inputs and flushing of regenerated P and N occurred during peak snowmelt resulting in low annual retention. Initial accumulation of flooded forest material and input of organic matter by beaver may be very important to P and N dynamics, representing a long-term source of nutrients to the pond water and outflow.

scholarly journals Experimental approaches to creating a tissue-specific matrix for a bioartificial liver

2020 ◽  
Vol 22 (3) ◽  
pp. 123-133
Author(s):  
A. M. Grigoriev ◽  
Yu. B. Basok ◽  
A. D. Kirillova ◽  
L. A. Kirsanova ◽  
N. P. Shmerko ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Metabolic Activity ◽  
Human Liver ◽  
Culture Medium ◽  
Alternative Methods ◽  
Tissue Specific ◽  
The Matrix ◽  
Flow Through ◽  
Liver Fragments ◽  
Static Conditions

Shortage of donor organs for liver transplantation in the treatment of end-stage liver disease dictates the need to develop alternative methods that include technologies on tissue engineering and regenerative medicine. Objective: to study the ability of a tissue-specific matrix from decellularized human liver fragments (DHLF) to maintain adhesion and proliferation of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs) and HepG2 under static conditions and in a flow-through bioreactor. Materials and methods. Treatment with surfactants (SAS) – sodium dodecyl sulfate, Triton X-100 – followed by exposure to DNase was used for decellularization of human liver fragments (no more than 8 mm3). Biochemical screening included the determination of DNA quantity in the test samples. Efficiency of surfactant washing was assessed by the cytotoxicity of the matrix in the NIH 3T3 fibroblast culture. Viability and metabolic activity of cells were assessed via vital staining with a complex of fluorescent dyes LIVE/DEAD ® and PrestoBlue™ (Invitrogen, USA). Morphological examination of the liver cell-engineered constructs was carried out through histological staining and scanning electron microscopy with lanthanide contrast. Results. It was shown that the liver decellularization method used allows to obtain a biocompatible matrix with a residual DNA quantity <1%, which is capable of maintaining adhesion and proliferation of hAT-MSCs and HepG2. On day 7 of cultivation in the bioreactor, there was formation of a single conglomerate of the DHLF matrix with numerous groups of viable cells with a high nuclear-cytoplasmic ratio. The urea content in the culture medium is 1.5 ± 0.1 mmol/L, exceeding that of samples obtained under static conditions. This indicates the metabolic activity of HepG2 in the composition of the obtained culture systems. It was shown that constant flow of the culture medium in the perfusion bioreactor increased the proliferative activity of HepG2 and allowed to provide a more uniform colonization by matrix cells in comparison with static cultivation conditions. Conclusion. The conditions for uniform colonization of DHLFs in a flow-through bioreactor with cell cultures were established. The ability of the matrix to maintain adhesion and proliferation of hADSCs and HepG2 for 11 days indicates that it could be used in liver tissue engineering.

Research on the performance of electro-hydraulic proportional flow valve controlled by active pilot pump

2016 ◽  
Vol 231 (4) ◽  
pp. 720-731 ◽  
Author(s):  
Yunxiao Hao ◽  
Long Quan ◽  
Jiahai Huang
Keyword(s):  
Pressure Differential ◽  
Small Displacement ◽  
Flow Pulsation ◽  
Pump Speed ◽  
Pump Flow ◽  
Flow Capacity ◽  
Flow Through ◽  
Large Flow ◽  
Proportional Flow ◽  
Flow Valve

The cartridge flow valves, used in heavy machine and equipment, have the advantages of low leakage, large flow capacity, simple structure, and ease of modulation. However, in order to reduce the influence of load variety on the flow through valve, a pressure differential compensator or a cartridge type flow sensor should be added to the proportional throttle valve. These methods have disadvantages of reducing the flow capacity of valve and increasing the throttling loss. To overcome these disadvantages, a low energy consumption, high controllable electro-hydraulic proportional flow valve which consists of a hydraulic transistor (Valvistor) and a small displacement hydraulic pump driven by a servo motor is proposed firstly in the world. As the pump flow is basically proportional to the pump speed and little influenced by load variety, the flow through main valve is proportional to pilot pump speed. In the research, it’s known that feedback throttle slot pre-opening will cause the decrease of the main valve flow as pressure drop increases. So, small orifices are used instead of the pre-opening of feedback throttle slot to reduce the influence of load variety on the flow through valve. Furthermore, a method of pressure differential changing with pilot pump rotational speed calibration is introduced to further mitigate the influence of pressure difference. In this paper, the mathematical dynamic model of the valve is also established and the stability criterion of valve is derived. The influence of valve parameters and the flow pulsation of pilot pump on valve flow performance is analyzed and simulated. In view of the pilot pump flow pulsation frequency being much higher than the valve natural frequency, the research shows that the influence of flow pulsation of pilot pump on valve flow performance is very little. The research work provides a new method for the large flow electro-hydraulic proportional control system.

Dehalococcoides abundance and alternate electron acceptor effects on large, flow-through trichloroethene dechlorinating columns

2015 ◽  
Vol 100 (5) ◽  
pp. 2367-2379 ◽  
Author(s):  
Babur S. Mirza ◽  
Darwin L. Sorensen ◽  
R. Ryan Dupont ◽  
Joan E. McLean
Keyword(s):  
Electron Acceptor ◽  
Flow Through ◽  
Large Flow
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