Bipolar Design Research Articles

Dislocation of hemiarthroplasty after hip fracture is common and the risk is increased with posterior approach: result from a national cohort of 25,678 individuals in the Swedish Hip Arthroplasty Register

Background and purpose — Reported revision rates due to dislocation after hemiarthroplasty span a wide range. Dislocations treated with closed reduction are rarely reported despite the fact that they can be expected to constitute most of the dislocations that occur. We aimed to describe the total dislocation rate on the national level, and to identify risk factors for dislocation. Patients and methods — We co-processed a national cohort of 25,678 patients in the Swedish Hip Arthroplasty Register, with the National Patient Register (NPR) and Statistics Sweden. Dislocation was defined as the occurrence of any ICD-10 or procedural code related to hip dislocation recorded in the NPR, with a minimum of 1-year-follow-up. In theory, all early dislocations should thereby be traced, including those treated with closed reduction only. Results — 366/13,769 (2.7%) patients operated on with direct lateral approach dislocated, compared with 850/11,834 (7.2%) of those with posterior approach. Posterior approach was the strongest risk factor for dislocation (OR = 2.7; 95% CI 2.3–3.1), followed by dementia (OR = 1.3; CI 1.1–1.5). The older the patients, the lower the risk of dislocation (OR = 0.98 per year of age; CI 0.98–1.0). Neither bipolar design nor cementless stems influenced the risk. Interpretation — The choice of posterior approach and dementia was associated with an increased dislocation risk. When hips treated with closed reduction were identified, the frequency of dislocation with use of direct lateral and posterior approach more than doubled and tripled, respectively, compared with when only revisions due to dislocation are measured.

Transparent organic upconversion device targeting high- grade infrared visual image

Infrared-to-visible transparent upconverter offers an appealing prospect of demonstrating in situ invisible information without interfering with the intrinsic vision of human eyes. However, previous studies required high operational voltage for visible light emission failing to meet the prerequisite of practical application. Here, we report an organic upconversion device composed of a single photoactive material ClAlPc for sensing infrared light and subsequent visualization by BCzPh:CN-T2T exciplex co-hosted phosphorescent light-emitting diode. Incident NIR signal (λmax at 780 nm) is upconverted into visible light emission (λmax at 523 nm) under an onset bias voltage of merely 1.7 V by the virtue of barrier-less bipolar exciplex design. Particularly, the device exhibits linear dynamic luminance toward NIR power density down to 34 μW/cm2 and real-time response to frequency-modulated NIR signal up to 10 kHz. By comprising a transparent multilayered electrode for see-through upconverter, a high-quality infrared visual image with a maximum resolution of 1588 dpi is demonstrated.

A registry study on radial head arthroplasties in the Netherlands: Indications, types and short-term survival.

This study aims to use the Dutch Arthroplasty Register data to report an overview of the contemporary indications and implant designs, and report the short-term survival of radial head arthroplasty. From the Dutch Arthroplasty Register, data on patient demographics, surgery and revision were extracted for radial head arthroplasties performed from January 2014 to December 2019. Implant survival was calculated using the Kaplan-Meier method. Two hundred fifty-eight arthroplasties were included with a median follow-up of 2.2 years. The most common indication was a fracture of the radial head (178, 69%). One hundred thirty-nine (68%) of the prostheses were of bipolar design, and the most commonly used implant type was the Radial Head System (Tornier; 134, 51%). Of the 258 included radial head arthroplasties, 16 were revised at a median of six months after surgery. Reason for revision was predominantly aseptic loosening (9). The overall implant survival was 95.8% after one year, 90.5% after three years and 89.5% after five years. For radial head arthroplasties, acute trauma is the most common indication and Radial Head System the most commonly used implant. The implant survival is 89.5% after five years.

Comparison of radiofrequency ablation processes for monopolar and bipolar systems

Most of the manufactured radiofrequency ablation devices use single electrodes inserted into the tumor for heating. In order to increase the volume of heating, they are cooled from the inside, and some have a system for wetting the outer surface of the electrode with saline. The need for necrosis of tumors with a diameter of more than 3 cm made us look for other design solutions that would significantly increase the volume of heated tissue. At the beginning, these were attempts to increase the number of heat sources inside the tumor by opening additional wires in the tumor, then the transition began to increase the number of electrodes to three and increase the number of working zones on each electrode. As a result, heating volumes of 90 cm3 were achieved with a heating time of 45 min. A study of the scientific and technical literature on RFA showed that foreign firms producing ablation devices already understand the need to replace monopolar electrodes with bipolar multi-electrode devices. The reason for this is not only the better postoperative characteristics of the use of bipolar electrodes, but also the emergence, in addition to oncology, of new areas of ablation application, where more complex forms of thermal fields are used during therapy, for example, tubular zones of necrosis. A radical solution to the problem of increasing the volume of coagulation is the transition from monopolar single electrodes to bipolar multielectrode designs. In this case, the electric field is concentrated in the areas between the electrodes and the heating efficiency increases significantly throughout the tumor volume, including the peripheral part. The most effective way is to incorporate bipolar electrodes into a circular cluster, allowing all electrodes to work simultaneously. Under the control of an ultrasound scanner, 4 to 12 electrodes are inserted, operating in bipolar mode. A model has been developed and the design of a four-electrode cluster has been developed, which allows for distributed heating of the tumor in a bipolar mode. As a result of the studies carried out, it was found that the use of bipolar systems allows: to significantly increase the volume of the area of necrosis due to the possibility of increasing the power supplied to the tumor; to reduce the unevenness of heating over the volume of the tumor by obtaining temperature fields, the shape of which is closest to the required one; improve patient survival rates by placing electrodes outside the tumor (“NO TOUCH” mode). The work performed indicates the technical possibility of a significant increase in the volume of destroyed tissue by increasing the number of electrodes and placing electrodes along the tumor volume closer to the periphery, including the ablastic zone. As a result, it became possible to heat tumors from their periphery without contacting the electrodes with the tumor. The increase in the number of heat sources made it possible not only to reduce the load on the electrodes, but also to shorten the procedure time. Ablation of large volumes entailed an inevitable increase in the number of electrodes in a multi-electrode system, which led to the complication of their connection to the generator. So far, an unresolved problem remains to reduce the total impedance of the generator load.

Revision Risk After Unipolar or Bipolar Hemiarthroplasty for Femoral Neck Fractures: An Instrumental Variable Analysis of 62,875 Procedures from the Australian Orthopaedic Association National Joint Replacement Registry.

There remains much international practice variation regarding the choice of a unipolar or bipolar prosthesis design for displaced femoral neck fractures that are treated with hemiarthroplasty. The purpose of the present study was to compare revision rates following primary hemiarthroplasty for femoral neck fracture to determine if the unipolar hemiarthroplasty design increases the risk of revision arthroplasty for all causes. Instrumental variable analysis was performed with use of data that had been entered into the Australian Orthopaedic Association National Joint Replacement Registry from September 1, 1999, to December 31, 2018. Sixty-two thousand, eight hundred and seventy-five patients with femoral neck fractures that were treated with primary modular unipolar or bipolar hemiarthroplasty procedure were analyzed. Hospital preference for prosthesis design in the 12 months prior to the index procedure was used as an instrument to adjust for unmeasured confounding. The primary outcome was time to first revision for any cause. Secondary analyses were performed on the reason for revision (infection, dislocation, periprosthetic fracture, or acetabular erosion), the use of cement femoral stem fixation, and the type of stem (polished or matte). Modular unipolar hemiarthroplasty was associated with a higher rate of revision at >2.5 years (hazard ratio [HR], 1.86; 95% confidence interval [CI], 1.46 to 2.36; p < 0.001), but there was no difference between the groups before 2.5 years (HR, 0.98; 95% CI, 0.85 to 1.13; p = 0.79). Protective factors for revision included female sex (HR, 0.82; 95% CI, 0.74 to 0.9), use of cemented fixation (HR, 0.69; 95% CI, 0.62 to 0.77), and surgery performed in a public hospital setting (HR 0.79; 95% CI, 0.70 to 0.89). Modular unipolar prostheses had a greater risk of revision for acetabular erosion, particularly in later time periods (HR at ≥5.5 years, 5.10; 95% CI, 2.40 to 10.83; p < 0.001), while being protective against periprosthetic fractures (HR, 0.72; 95% CI, 0.59 to 0.87; p < 0.001) at all time points. There was no difference in terms of the risk of revision for infection, dislocation, or stem type. Bipolar hemiarthroplasty designs resulted in a lower risk of revision than unipolar designs. Unipolar hemiarthroplasties are justified for patients with femoral neck fracture and a shorter life expectancy (≤2.5 years). Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Association of tobacco smoking with bipolar affective disorder- a comparative cross-sectional study at a tertiary care centre in south India

Background: Smokers with psychiatric disorders, most notably those with serious mental illness and substance use disorders tend to present with more severe nicotine dependence and nicotine withdrawal than smokers without these illnesses. The following study aims to explore the correlation of smoking with bipolar affective disorder Setting and design: The comparative cross-sectional study was done in Amrita Institute of Medical Sciences & Research Centre, Kochi, a 1,450-bed hospital for a period of 2 years. Methods and materials: Seventy subjects with Bipolar affective Disorder who were in remission for at least two months and Seventy subjects who were relatives of paediatric outpatients were included in the study and control group, respectively. Clinical variables were assessed, and Hamilton depression rating scale, Young mania rating scale and Fagerstorm nicotine rating scale were administered to the subjects. Results: In this study, 52.9% of subjects with bipolar disorder were found to be smokers, and 51.4% of the normal population were smokers. No significant association was observed between bipolar affective disorder, and smoking tobacco, however, a significant correlation was found between smoking status and the total number of episodes of the disorder, psychotic episodes and suicide attempts. Conclusion: There appears to be a relationship between smoking tobacco and certain clinical features of bipolar affective disorder. It is possibly a bidirectional relation between these two disorders.

Recent Advances in Bipolar Membrane Design and Applications

Integration of bipolar membranes (BPMs) into electrochemical cells is an established method for acid and base generation, as well as desalinization methods. More recently, BPMs have been recognized...

Bipolar plate design and fabrication using graphite reinforced composite laminate for proton exchange membrane fuel cells

A bipolar plate is designed to have high electric conductivity, low corrosion and good mechanical strength characteristics. The two most common materials adopted for bipolar plates are carbon and metal. The carbon bipolar plate has good electric conductivity and corrosion resistance but brittle. The metal bipolar plate has good mechanical strength, acceptable electrical conductivity but worse corrosion resistance. The main objective of this paper is to design and fabricate graphite composite laminate based PEMFC bipolar plate. A thermoset type phenolic resin is adopted as the matrix with a plain weave type woven graphite fiber cloth adopted as the composite laminate reinforcement. In the fabrication process, thermoset phenol-formaldehyde resin is first printed onto the plain-weave woven carbon fiber cloth and the waiting until air-dry as prepregs. Several layers of prepregs were then stacked into a mold and heated. The resin contained in the prepregs melted and cured into a composite laminate. The carbonization process is further conducted to increase the electric conductivity. The flow channels are carved and the bipolar plate is completely fabricated. The developed bipolar plates are assembled into a single cell PEMFC and tested. The composite bipolar plate performance with or without carbonization are also studied. The back side bipolar plate electric conductivity would also significantly affect the cell performance. Therefore, increasing the back side conductivity could increase the cell performance.

Decision Making in Femoral Neck Fractures: Internal Fixation versus Arthroplasty

The article's abstract is no available.

The Role of Bi-Polar Plate Design and the Start-Up Protocol in the Spatiotemporal Dynamics during Solid Oxide Fuel Cell Anode Reduction

Start-up conditions largely dictate the performance longevity for solid oxide fuel cells (SOFCs). The SOFC anode is typically deposited as NiO-ceramic that is reduced to Ni-ceramic during start-up. Effective reduction is imperative to ensuring that the anode is electrochemically active and able to produce electronic and ionic current; the bi-polar plates (BPP) next to the anode allow the transport of current and gases, via land and channels, respectively. This study investigates a commercial SOFC stack that failed following a typical start-up procedure. The BPP design was found to substantially affect the spatiotemporal dynamics of the anode reduction; Raman spectroscopy detected electrochemically inactive NiO on the anode surface below the BPP land-contacts; X-ray computed tomography (CT) and scanning electron microscopy (SEM) identified associated contrasts in the electrode porosity, confirming the extension of heterogeneous features beyond the anode surface, towards the electrolyte-anode interface. Failure studies such as this are important for improving statistical confidence in commercial SOFCs and ultimately their competitiveness within the mass-market. Moreover, the spatiotemporal information presented here may aid in the development of novel BPP design and improved reduction protocol methods that minimize cell and stack strain, and thus maximize cell longevity.

3D Ion‐Conducting, Scalable, and Mechanically Reinforced Ceramic Film for High Voltage Solid‐State Batteries

AbstractConcerning the safety aspects of Li+ ion batteries, an epoxy‐reinforced thin ceramic film (ERTCF) is prepared by firing and sintering a slurry‐casted composite powder film. The ERTCF is composed of Li+ ion conduction channels and is made of high amounts of sintered ceramic Li1+xTi2‐xAlx(PO4)3 (LATP) and epoxy polymer with enhanced mechanical properties for solid‐state batteries. The 2D and 3D characterizations are conducted not only for showing continuous Li+ ion channels thorough LATP ceramic channels with over 10−4 S cm−1 of ionic conductivity but also to investigate small amounts of epoxy polymer with enhanced mechanical properties. Solid‐state Li+ ion cells are fabricated using the ERTCF and they show initial charge–discharge capacities of 139/133 mAh g−1. Furthermore, the scope of the ERTCF is expanded to high‐voltage (&gt;8 V) solid‐state Li+ ion batteries through a bipolar stacked cell design. Hence, it is expected that the present investigation will significantly contribute in the preparation of the next generation reinforced thin ceramic film electrolytes for high‐voltage solid‐state batteries.

Estimation of through-plane and in-plane gas permeability across gas diffusion layers (GDLs): Comparison with equivalent permeability in bipolar plates and relation to fuel cell performance

The present work focusses on measuring the permeability across gas diffusion layers (GDLs) first in a dedicated cell and later in PEM fuel cell configuration with varying bi-polar plate designs. Eight carbon paper-based GDLs with and without the microporous layer (MPL), have been tested. An in-house designed dedicated cell allowed measuring pressure drop depending on flow rate, for i) through-plane and ii) in-plane direction. Further, transport measurements were conducted in 25 cm2 bi-polar plates (BPs) in fuel cell configuration having single or multiple serpentine channels, by stacking the GDL inside. The results show that gas permeability in the dedicated cell for through-plane and in-plane can be estimated by using Darcy's law. However, for BPs, the flow is affected additionally by inertial contribution (Darcy-Forchheimer). Finally, the efficiency allowed by selected GDLs installed in a fuel cell under operation shows a relationship between the equivalent permeability and the fuel cell performance.

Comparison of bipolar and monopolar radial head prostheses in elbow fracture-dislocation

IntroductionThe role of bipolar radial head prostheses (RHP) in elbow fracture-dislocation is controversial, with some reports of poorer stabilization than with monopolar designs. The aim of the present study was to compare mono- versus bi-polar RHPs in elbow fracture-dislocation. The study hypothesis was that mono- and bi-polar RHPs do not differ in clinical and radiological results, complications or revision rates. Material and methodsA single-center retrospective study included 58 patients, with a mean age of 55 years (range, 21–84 years). All received RHP for elbow dislocation with association: terrible triad, Monteggia fracture-dislocation, transolecranal dislocation or divergent dislocation. Two groups were compared: Mono-RHP, with monopolar prosthesis (n=40), and Bi-RHP, with bipolar prosthesis (n=18). All patients underwent clinical and radiological examination at last follow-up. ResultsMean follow-up was 42.7 months (range, 12–131 months). There were no significant (p>0.05) inter-group differences in range of motion or Mayo Elbow Performance Score. Mono- versus bi-polar design did not correlate with onset of complications (p=0.89), surgical revision (p=0.71), persistent or recurrent instability (p=0.59), or ulnohumeral (p=0.62) or capitulum (p=0.159) osteoarthritis at last follow-up. Discussion and conclusionNo differences were found between mono- and bi-polar RHPs in the treatment of elbow fracture-dislocation. Clinical and radiographic results were similar, as were complications and revision rates. The literature is inconclusive, reporting contradictory conclusions. We see no contraindications to bipolar RHPs in elbow dislocation with association, notably terrible triad injury. Level of evidenceIII, Retrospective case-control study.

An exploratory study on computer-aided affective product design based on crowdsourcing

This research investigates the possibility of incorporating affective factors in 3D model creation using handbags as an exemplary product. We demonstrate a crowd-based experimental approach that establishes the correlations between human emotional responses described by bi-polar adjectives and design factors of a bag. A factorial experiment is conducted to understand which design factors independently and/or interactively influence the responses by systematically varying 3D bag models. In-depth statistical analysis of the experimental results indicates that increasing the bag height makes it look more casual; a black bag tends to look luxurious and formal; a bag made of linen feels more classic and sophisticated. Those insights provide a basis for implementing a prototyping design tool that enables users to create 3D bag models with certain affective features using free-form deformation. The proposed approach demonstrates the preliminary feasibility of improving Kansei Engineering applications with big data obtained from crowdsourcing.

패시브 타입 공랭식 연료전지 성능향상을 위한 캐소드 채널 폭 비율에 대한 수치해석적 연구

In general, a passive air cooled proton exchange membrane fuel cell (PEMFC) operates under an excessive amount of air flow and low humidification conditions, indicating effective control of stack temperature and membrane hydration is of paramount importance for achieving high and stable performance. In this study, we numerically investigate the effects of cathode bipolar plate flowfield design on temperature and water distributions inside a passive air cooled PEMFC. The three-dimensional (3D) non-isothermal PEMFC model is applied to various PEMFC geometries where three different flowfield designs with different ratio and dimensions of air supply channel and cooling channels are taken into account. Simulation results show that the flowfield design with narrow air supply channel and/or wide cooling channel exhibits superior water management performance whereas the effect of oyxgen depletion is minimal due to sufficiently a large amount of air supply conditions. This study clearly demonstrates that the membrane dehydration issue in a passive type air cooled PEMFC can be mitigated by proper design of cathode flowfield.

Bipolar electrochemical capacitors using double-sided carbon nanotubes on graphite electrodes

The electrochemical capacitor (EC) is a key enabler for the miniaturized self-powered systems expected to become ubiquitous with the advent of the internet-of-things (IoT). Vertically aligned carbon nanotubes (VACNTs) on graphite holds promise as electrodes for compact and low-loss ECs. However, as with all ECs, the operating voltage is low, and miniaturization of higher voltage devices necessitates a bipolar design. In this paper, we demonstrate a bipolar EC using graphite/VACNTs electrodes fabricated using a joule heating chemical vapor deposition (CVD) setup. The constructed EC contains one layer of double-sided VACNTs on graphite as bipolar electrode. Compared to a series connection of two individual devices, the bipolar EC has 22% boost in volumetric energy density. More significant boost is envisaged for stacking more bipolar electrode layers. The energy enhancement is achieved without aggravating self-discharge (71.2% retention after 1 h), and at no sacrifice of cycling stability (96.7% over 50000 cycles) owing to uniform growth of VACNTs and thus eliminating cell imbalance problems.

Analysis of Quantum-well Heterojunction Emitter Bipolar Transistor Design

The paper presents the analysis of Quantum-well Heterojunction Emitted Bipolar Transistor Design based on physical parameters with numerical computations. The specific objective of this work is to enhance the physical performance of the Quantum-well Heterojunction Emitted Bipolar Transistor Design in real world applications. There have been considered on the III-V compound materials like GaAs for p-type layer, AlGaAs for n-type layer and InGaAs for quantum-well layer for different kinds of junctions which were developed in HEBT structure. In this analyses, the parameters for implemented HEBT structure were evaluated to find the multi-quantum-well band diagram, operating frequency (unity beta frequency), rise time, storage delay time, fall time, minority carrier distribution, current gain variation, voltage-current characteristics and phonon control on quantum-well device. In these analyses, the physical parameters were carried out based on the experimental studies from the recent research works and many literatures. The physical parameters which used in this HEBT structure have been provided to solve the real fabrication problems by using theoretical concepts. The quantum-well device based on III-V compound materials was performed by using numerical techniques with the help of MATLAB. The simulation results confirm that the developed HEBT structure was suitable for fabricating the real devices for high performance applications.

A FLOW CHANNEL WITH NAFION MEMBRANE MATERIAL DESIGN OF PEM FUEL CELL

This study is about flow channels in the design of the PEM (Proton Exchange Membrane) fuel cell system. In the experimental study, different flow geometry, Nafion membrane, and bipolar plate gas diffusion channel designs are available. In some cases, the techno-economic analysis method is applied. Cost analysis for the design has also been made and compared with similar studies. It was obtained that the new flow channel design increased the PEM fuel cell performance. A unit energy cost was set to 42.6 [$/W]. When a similar system was implemented for a year, the annual energy cost was calculated to be 25.48 [$/y]. The aim of this study is to determine the cost-benefit analysis of PEM fuel cell with a combined flow channel design. In addition, the simple payback period was found to be 0.81 [y]. Thus, the PEM fuel cell was determined by the techno-economic analysis calculation, in which energy savings can be achieved by the flow channel design. &amp;nbsp;

Simulations of a New Flow Channel Design of Bipolar Plates for a Fuel Cell Type PEM By CFD

Nowadays, there is an increasing tendency towards renewable energy due to the limitation and pollution of fossil fuel. Among these energies, the fuel cell is a suitable technology with its high-power density converting chemical energy to electricity. Fuel cells are a highly efficient, environmentally friendly power source with broad applications in many industries including transportation as well as portable and stationary power generation, which will translate the chemical energy stored directly in the fuel and oxidizer into electrical energy. The proton exchange membrane fuel cell (PEMFC) is a useful type of fuel cell due to its high efficiency, high energy densities and low corrosion [1]. Other advantages of PEMFCs are their low operating temperature (40-90°) and planar geometry which allows many cells to be stacked together in order to obtain an appropriate size. Manufacturing and operating costs of this type of fuel cell can be reduced by optimizing the efficiency of fuel cells through detailed analysis of complex electrochemical and mass transport phenomena that occur within the cells [2]. It is very well known that the bipolar plate is an important component of the fuel cell, the design of the fuel cell is largely bipolar plate design, and especially the design of the flow field is a top priority [3]. In this context, this work deals with the simulation of a complete PEM fuel cell, emphasizing the novel design of the flow channels of the bipolar plates. The simulation was performed in a single cell configuration using the Navier-Stokes equations for the flow channels, the Brinkman equation for the gas diffusion layer, and for the mass transport the Maxwell-Stefan equations. Finally, for the simulation of the current distribution in the catalytic layer, the Butler-Volmer equation was adapted to the mass transport. The new design allowed a better dispersion of the gases inside the channels, avoiding water stagnation and increasing the efficiency of the fuel cell.

Improvements to Integrate Alkaline Water Electrolyzers for H2 Production from Renewable Sources

This presentation provides an overview of the alkaline water electrolysis for hydrogen production and discusses examples of previous and current research activities in KIER, and future opportunities for improvements of this technology. The challenges in material developments including electrodes and a separator to improve the cell performance and durability of alkaline electrolysis as advance designs will be introduced. The compact Unitized Bipolar Electrodes design was applied to evaluate the in situ single cell performance of AWE cells. Porous Ni-Zn-(Fe) electrodes as HER electrodes that were prepared by the electrodeposition method followed by the selective chemical etching of Zn in KOH. For the OER electrodes, Nix-Fe1-x Layered Double Hydroxide(LDH, x=0.5~0.7), which have shown the 100-fold OER activity enhancement over Ni in ex-situ studies was directly grown on metal lath and foams. Electro-activity of the AWE cell with Nix-Fe1-x LDH ＆ Ni-Zn-P electrodes toward HER/ OER has exhibited high-performance at 200 ＆ 600 mA/cm2, as a voltage efficiency of 97 ＆ 80% respectively, which is comparable to that of the well-developed commercial alkaline water electrolyzer.