scholarly journals Experimental study and modelling of asphaltene deposition on metal surfaces with superhydrophobic and low sliding angle inner coatings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Haji-Savameri ◽  
Saeid Norouzi-Apourvari ◽  
Ahmad Irannejad ◽  
Abdolhossein Hemmati-Sarapardeh ◽  
Mahin Schaffie ◽  
...  
Keyword(s):  
Metal Surfaces ◽  
Dynamic State ◽  
Flow State ◽  
Sliding Angle ◽  
Static State ◽  
Double Exponential ◽  
Asphaltene Deposition ◽  
Coated Surfaces ◽  
Model Oil ◽  
Coated Electrodes

AbstractInner coatings have emerged as a novel technique to prevent the deposition of paraffin, wax, scale, and corrosion of pipelines during oil production and transport. Few studies addressed this technique for preventing asphaltene deposition. In this study, two superhydrophobic inner coatings, including polytetrafluoroethylene (PTFE) coating and nanosilica coating, were fabricated on metal surfaces and the asphaltene deposition on these coated surfaces was examined. A model oil solution was prepared using asphaltene and heptol and the effect of static and dynamic flow states on the amount of asphaltene deposition on uncoated electrodes, PTFE coated electrodes, and nanosilica coated electrodes were investigated. The results showed that the PTFE coating is more effective in reducing asphaltene deposition than nanosilica coating. The PTFE coating could reduce 56% of the deposition in a static state and more than 70% in a dynamic state at an asphaltene concentration of 2000 ppm. For PTFE coating in a dynamic state, the deposition rate is negligible in long times. In addition, it was found that the type of flow state affects the asphaltene deposition kinetics. The results demonstrate that, in the static state, the nth-order kinetics model, and in the dynamic state, the double exponential models are in best agreement with the experimental data.

Increase of energy efficiency ratio of a direct evaporative cooler by dynamic behavior with energy and exergy analysis

2021 ◽  
pp. 095440622110420
Author(s):  
Behzad Omidi Kashani
Keyword(s):  
Energy Efficiency ◽  
Electrical Energy ◽  
Coefficient Of Performance ◽  
Dynamic State ◽  
Circulation Rate ◽  
Cooling Load ◽  
Efficiency Ratio ◽  
Static State ◽  
Circulation Pump ◽  
Water Rate

The present research is about increasing the energy efficiency ratio (EER) in current direct evaporative coolers (DEC) in Iran. Increasing the cooling load and reducing the electrical energy consumption simultaneously (increasing the energy efficiency ratio (EER)) in DEC are the main goals of manufacturers and consumers of this device. When the circulation water pump runs continuously (static state), the circulation water rate is about 1.89 to 2.90 times of the amounts recommended in the reasonable standards. In order to adjust the circulation water rate to the recommended amount by standards, the present study has utilized repetitive cyclic scheduling programs to reduce the circulation rate to the optimal amount, (by turning the circulation pump on and off by dynamic pattern operation). In other words, the circulation pump stays on only for a certain period of a working cycle, and then the pump stays off for the rest of it. The cooling load and EER were measured based on ASHRAE 133 (2015). The results indicated that the cooling load in the dynamic state increased by 5.03 and 6.18 percent compared to the static state at low and high fan speeds, respectively. Moreover, in comparison with the static state, the amount of electrical energy consumed (kW-hr) in the dynamic state decreased by 8.8 and 4.2 percent at low and high fan speeds, respectively. Finally, the coefficient of performance (COP or EER) of the DEC in the dynamic state is increased by 15.16 and 10.78 in comparison with the static state at low and high fan speeds, respectively.

Effects of Additives in KOH Based Electrolytes on Cu ECMP

2007 ◽  
Vol 991 ◽  
Author(s):  
Tae-Young Kwon ◽  
In-Kwon Kim ◽  
Jin-Goo Park
Keyword(s):  
Citric Acid ◽  
Applied Voltage ◽  
Counter Electrode ◽  
Corrosion Potential ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Corrosion Current ◽  
Dynamic State ◽  
Static State ◽  
Potentiodynamic Curves

ABSTRACTThe purpose of this study was to characterize KOH based electrolytes and effects of additives on electro-chemical mechanical planarization. The electrochemical mechanical polisher was made to measure the potentiodynamic curve and removal rate of Cu. The potentiodynamic curves were measured in static and dynamic states in investigated electrolytes using a potentiostat. Cu disk of 2 inch was used as a working electrode and Pt electroplated platen was used as a counter electrode. KOH was used as the electrolyte. H2O2 and citric acid were used as additives for the ECMP of Cu. In static and dynamic potentiodynamic measurements, the corrosion potential decreased and corrosion current increased as a function of KOH concentration. In dynamic state, different potentiodynamic curve was obtained when compared to the static state. The current density did not decrease in passivation region by mechanical polishing effect. The static etch and removal rate were measured as function of KOH concentration and applied voltage. In ECMP system, polishing was performed at 30 rpm and 1 psi. The removal rate was about 60 nm/min at 0.3 V when 5 wt% KOH was used. Also, the effect of additive was investigated in KOH based electrolyte on removal rates. As a result, The removal rate was increased to 350 nm/min when 5wt% KOH, 5vol% H2O2, 0.3 M citric acid were used.

State Estimation of Active Distribution Networks

2020 ◽  
pp. 270-308
Author(s):  
Razan Al Rhia ◽  
Haithm Daghrour
Keyword(s):  
State Estimation ◽  
Distribution System ◽  
Distribution Systems ◽  
Operating Performance ◽  
Distribution Networks ◽  
Dynamic State ◽  
State Estimator ◽  
Static State ◽  
Active Distribution Networks

Monitoring and controlling the electrical distribution system for real time is becoming very important to improve its operating performance after transition to active distribution systems. So, many sensors are needed to monitor all parts in the systems. But if sensors are installed at all buses, investment cost becomes huge. To reduce the number of sensors, state estimation approach can be used to estimate the voltage of buses, which do not have sensors. State Estimation (SE) algorithms are broadly classified into Static State Estimator (SSE) and Dynamic State Estimator (DSE). This chapter classifies most algorithms used in active distribution networks, also State estimation in unbalanced distribution systems, and Role of PMU in Distribution System State Estimation.

Experiment analysis of spindle performance with rolling bearing under non-uniform preload

2016 ◽  
Vol 230 (17) ◽  
pp. 3135-3146 ◽  
Author(s):  
Xiao-hu Li ◽  
Yan-fei Zhang ◽  
Jun Hong ◽  
Hong Zhao ◽  
Huan-feng Li
Keyword(s):  
Uniform Distribution ◽  
Reference Value ◽  
Bending Moment ◽  
Rolling Bearing ◽  
Test System ◽  
Dynamic State ◽  
Static State ◽  
Spindle Shaft ◽  
Action Point ◽  
Manufacturing Errors

As a result of the manufacturing errors in the main parts of spindle, and the errors in assembly process of spindle, as well as the non-uniform heat distribution during spindle operation, the non-uniformly distributed preload in rolling bearing is inevitable. The non-uniform preload has not only axial force on the rolling bearing, but also the bending moment around the rolling bearing center. The effect of preload in bearing being non-uniform on the spindle performance is still unclear. In order to analyze the spindle performance with rolling bearing under non-uniform preload, a spindle test system with adjustable non-uniform distribution preload is built. By changing the magnitude of preload force on each action point, it can make the preload force distribute non-uniformly. In the static state of spindle, upon the change of non-uniformly distributed preload, the radial displacement of spindle shaft end is also changed, while in the dynamic state of spindle, it will lead to the change of the rotation center of spindle as a result of bending moment accompanying the non-uniform preload. Furthermore, the dynamic and static results show that when the preload is under non-uniform distribution, the spindle performance is significantly different from that under uniform preload. So this study would have certain reference value to check the spindle performance and explore novel preload method for rolling bearing.

Analysis on the Feet-Pressure between Flatfoot and Normal Foot

2012 ◽  
Vol 442 ◽  
pp. 149-153
Author(s):  
Wei Fei Fang
Keyword(s):  
Contact Area ◽  
Pressure Difference ◽  
Test System ◽  
Dynamic State ◽  
Bottom Pressure ◽  
Pressure Center ◽  
Static State ◽  
Great Capacity ◽  
Average Value

Inquire into normal foot and the foot bottom of the flatfoot pressure difference to provide a reference. Carring on footprint diagraph to 206 volunteers, is divided into normal foot according to the foot bow blank width in the footprint 157, 49 flatfoots.Adopt foot bottom pressure's distributing to test system is checked the foot bottom pressure to carry on diagraph to 2 sets.Measure medium be checked request to take off shoes and socks to tread Tai to walk as usual, take three average value, dynamic state's recording 2 sets is checked foot bottom pressure.As usual fully the contact area of heel and front forefootis bigger than flatfoot, p<0.05;As usual fully the bow contact area is smaller than flatfoot, p<0.05.As usual fully bow and front the blunt quantity that forefootis subjected to is smaller than flatfoot, p<0.05;Normal heel is hurtled Be had great capacity to flatfoot, p<0.05;Under static state and dynamic state circumstance the pressures of the forefootand the foot bow acceptance are all bigger than normal foot before the flatfoot, p<0.05.Conclusion:Flatfoot the pressure center is more intensive while hitting the ground, its foot bow and front the blunt quantity been subjected to by forefootis a little bit greatly.

scholarly journals RESEARCH ON THE POSTURE CONTROL IN REACHES A STATIC STATE FROM THE DYNAMIC STATE DURING THE MAXIMAL STEP LENGTH (MSL) ; YOUNG VERSUS OLDER ADULTS

2008 ◽  
Vol 57 (4) ◽  
pp. 423-432
Author(s):  
SANG-JUN PARK ◽  
HYUN-TAE PARK ◽  
HIROHARU KAMIOKA ◽  
SUNG-JIN PARK ◽  
TAIKI KOMATSU ◽  
...  
Keyword(s):  
Older Adults ◽  
Step Length ◽  
Posture Control ◽  
Dynamic State ◽  
Static State

scholarly journals Utilization of CD and DVD Pick-Up Heads for Scratch Inspection of Magnetic Disk in Dynamic State Using Microcontroller

2020 ◽  
Vol 10 (19) ◽  
pp. 6897
Author(s):  
Achinee Polsawat ◽  
Warunee Tipcharoen ◽  
Apirat Siritaratiwat
Keyword(s):  
Hard Disk Drive ◽  
Low Cost ◽  
Hard Disk ◽  
Disk Drive ◽  
Surface Characteristic ◽  
Dynamic State ◽  
Static State ◽  
Magnetic Disk ◽  
Shape Characteristic ◽  
In The Beginning

A non-destructive technique to inspect a scratch on all magnetic disks in the beginning process of hard disk drive (HDD) manufacturing by using CD and DVD pick-up heads as the detector is proposed. It requires a 100% disk inspection of micrometer-sized scratches in a quick measurement with low cost inventing. Most of the previous studies were in static state but this is the first time to be done in dynamic study using the microcontroller in order to promptly serve for industrial utilization. The size, position, and shape characteristic of scratches are examined using light reflection technique. The results show that, when the laser beam is targeted on a magnetic disk in a position, either scratch or non-scratch, the reflected light intensity differs. The DVD pick-up head can detect the width and the surface characteristic of the scratches, which is similar to the results from scanning electron microscope (SEM) for all scratches sizes less than 100 µm. It is also found that using a DVD pick-up head provides a better resolution of shape characteristic and roughness of scratches surface than a CD pick-up head. Hence, the scratch size of 10s µm scale on the magnetic disk can be accurately characterized by this proposed technique, which can be further utilized for magnetic disk inspection in the hard disk drive manufacturing process.

Research of Contact Pressure of an Elastoplastic Rough Body in Contact with a Smooth Rigid Plane

2010 ◽  
Vol 97-101 ◽  
pp. 1248-1252 ◽  
Author(s):  
Jian Meng Huang ◽  
Cheng Hui Gao
Keyword(s):  
Rough Surface ◽  
Contact Pressure ◽  
Fractal Theory ◽  
Frictional Heat ◽  
Dynamic State ◽  
Maximum Temperature ◽  
Real Contact Area ◽  
Static State ◽  
Mechanical Coupling ◽  
Rough Body

A thermo-mechanical coupling model for the rough surface is established. The model considers friction contact between a rigid flat plane and a rough surface based on 3D fractal theory and allows the analysis of the effects of elastic-plastic deformation of rough body and the interplay among asperities. The contact pressure distribution for the static state beneath different loading mode and for the dynamic state in the presence of the frictional heat flux is found. The results show the fluctuation of the average contact pressure during the process of loading is related to the velocity of loading. The synthetical function of multiple factors such as the thermal deformation, the rising temperature, the interaction between asperities makes the complicated relationships among the maximum temperature, the maximum contact pressure and the real contact area.

Data Assimilation for Strongly Nonlinear Problems by Transformed Ensemble Kalman Filter

SPE Journal ◽  
2014 ◽  
Vol 20 (01) ◽  
pp. 202-221 ◽  
Author(s):  
Qinzhuo Liao ◽  
Dongxiao Zhang
Keyword(s):  
Kalman Filter ◽  
Data Assimilation ◽  
Ensemble Kalman Filter ◽  
History Matching ◽  
Homogeneous Medium ◽  
Forward Model ◽  
Dynamic State ◽  
Initial Time ◽  
Static State ◽  
Strongly Nonlinear

Summary The ensemble Kalman filter (EnKF) has been widely used for data assimilation. It is challenging, however, when the relation of state and observation is strongly nonlinear. For example, near the flooding front in an immiscible flow, directly updating the saturation by use of the EnKF may lead to nonphysical results. One possible solution, which may be referred to as the restarted EnKF (REnKF), is to update the static state (e.g., permeability and porosity) and rerun the forward model from the initial time to obtain the updated dynamic state (e.g., pressure and saturation). However, it may become time-consuming, especially when the number of assimilation steps is large. In this study, we develop a transformed EnKF (TEnKF), in which the state is represented by displacement as an alternative variable. The displacement is first transformed from the forecasted state, then updated, and finally transformed back to obtain the updated state. Because the relation between displacement and observation is relatively linear, this new method provides a physically meaningful updated state without resolving the forward model. The TEnKF is tested in the history matching of multiphase flow in a 1D homogeneous medium, a 2D heterogeneous reservoir, and a 3D PUNQ-S3 model. The case studies show that the TEnKF produces physical results without the oscillation problem that occurs in the traditional EnKF, whereas the computational effort is reduced compared with the REnKF.

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