High Energy Transfer Research Articles

Selective sensing properties and enhanced ferromagnetism in CrI3 monolayer via gas adsorption

Recent fabrication of chromium triiodide (CrI3) monolayers has raised potential prospects of developing two-dimensional (2D) ferromagnetic materials for spintronic device applications. The low Curie temperature has stimulated further interest for improving the ferromagnetic stability of CrI3 monolayer. Here, based on density functional theory calculations, we investigated the adsorption energy, charge transfer, electronic and magnetic properties of gases (CO, CO2, N2, NH3, NO, NO2, O2, and SO2) adsorption on the CrI3 monolayer. It is found that CrI3 is sensitive to the NH3, NO, and NO2 adsorption due to the high adsorption energy and large charge transfer. The electrical transport results show that the conductivity of CrI3 monolayer is significantly reduced with the adsorption of N-based gases, suggesting that CrI3 exhibits superior sensitivity and selectivity toward N-based gases. In addition, the ferromagnetic stability and Curie temperature (T C) of CrI3 monolayer can be effectively enhanced by the adsorption of magnetic gases (NO, NO2, O2). This work not only demonstrates that CrI3 monolayer can be used as a promising candidate for gas sensing, but also brings further interest to tune the electronic and magnetic properties of 2D ferromagnetic materials via gas adsorption.

A Single-Event Burnout Hardened Super-Junction Trench SOI LDMOS with Additional Hole Leakage Paths

In this paper, a novel super-junction trench silicon-on-insulator laterally-diffused metal-oxide-semiconductor (SJT SOI LDMOS) power device with additional hole leakage paths to improve single-event burnout (SEB) performance under high liner energy transfer (LET) is proposed for the first time. The electrical characteristics and SEB performance of the proposed SJT SOI LDMOS are both enhanced effectively. The replacement of a lightly doped N drift region with a heavily doped P pillar and N pillar considerably improves the tradeoff between breakdown voltage (BVDS) and specific on-resistance (Ron,sp). Compared with the conventional trench SOI LDMOS (CT SOI LDMOS), the static figures of merit (FOM, BVDS2/Ron,sp) of the SJT SOI LDMOS increases by 239%. The SEB performance of the SJT SOI LDMOS is significantly improved as the holes induced by the heavy ion can be quickly absorbed to the trench source metal through the heavily doped P+ region and P buried region rather than the base resistor of the parasitic bipolar junction transistor (BJT). The SEB threshold voltage (VSEB) of the CT SOI LDMOS is 58 V (39% of the BVDS) and that of the SJT SOI LDMOS is up to 173 V (87% of the BVDS) at high LET of 1 pC/μm.

Dual-Emitting Ratiometric Luminescent Thermometers Based on Lanthanide Metal-Organic Complexes with Brønsted Acidic Ionic Liquids.

By introducing Brønsted acidic ionic liquids (ILs), two dual-emitting lanthanide metal-organic complexes (Ln-MOCs) of {[Ln(imdc)(CH3OH)(H2O)3]Cl2}n (LnIMDC, Ln = Eu and Tb, imdc = 1,3-bis(carboxymethyl)imidazolium ion) were first prepared under solvothermal conditions. The crystal structures of LnIMDC were measured by single-crystal X-ray diffraction, and the crystal growth process of LnIMDC was carefully studied. It is found that the crystals are three-dimensional supramolecular structures built up by Ln-O coordination bonds and supramolecular forces. In the temperature range of 303-403 K, LnIMDC show good temperature-dependent emission properties with maximum relative thermal sensitivities of 3.29% K-1 at 375 K and 2.08% K-1 at 303 K for EuIMDC and TbIMDC, respectively. It is worth mentioning that both EuIMDC and TbIMDC exhibit good linear ratiometric emission-temperature response in temperature ranges of 353-403 and 323-373 K, respectively, which render EuIMDC and TbIMDC good ratiometric thermometers in high temperature range. Computational studies on the energy level of ILs [H2imdc]Cl and [imdc]- ion were performed, which validated the high energy transfer efficiency between the [imdc]- and Ln3+ ions and the unique solution concentration- and wavelength-dependent fluorescence properties of [H2imdc]Cl. The high fluorescence performance opens up new opportunities for practical applications of ILs in optical sensing.

High-resolution Compton spectroscopy using x-ray microcalorimeters.

X-ray Compton spectroscopy is one of the few direct probes of the electron momentum distribution of bulk materials in ambient and operando environments. We report high-resolution inelastic x-ray scattering experiments with high momentum and energy transfer performed at a storage-ring-based high-energy x-ray light source facility using an x-ray transition-edge sensor (TES) microcalorimeter detector. The performance was compared with a silicon drift detector (SDD), an energy-resolving semiconductor detector, and Compton profiles were measured for lithium and cobalt oxide powders relevant to lithium-ion battery research. Spectroscopic analysis of the measured Compton profiles demonstrates the high-sensitivity to the low-Z elements and oxidation states. The line shape analysis of the measured Compton profiles in comparison with computed Hartree-Fock profiles is usually limited by the resolution of the semiconductor detector. We have characterized an x-ray TES microcalorimeter detector for high-resolution Compton scattering experiments using a bending magnet source at the Advanced Photon Source with a double crystal monochromator, providing monochromatic photon energies near 27.5keV. The momentum resolution below 0.16 atomic units (a.u.) was measured, yielding an improvement of more than a factor of 7 over a state-of-the-art SDD for the same scattering geometry. Furthermore, the lineshapes of narrow valence and broad core electron profiles of sealed lithium metal were clearly resolved using an x-ray TES compared to smeared and broadened lineshapes observed when using the SDD. High-resolution Compton scattering using the energy-resolving area detector shown here presents new opportunities for spatial imaging of electron momentum distributions for a wide class of materials with applications ranging from electrochemistry to condensed matter physics.

Application of artificial neural network for the ionizing radiation particle identification by the plastic scintillation detector response

The separation of ionizing radiation particles is an important and challenging task, especially regarding neutrons and gamma rays. The separation of neutron and gamma radiation is necessary for safeguard purposes and control of nuclear reactions. Standard mathematical models of pulse analysis work well in the presence of large energy transfer (>1 MeV) from the particle to the detector. However, the quality of the separation decreases as the amount of transferred energy lessens, making it impossible to determine the exact type of particle at a sufficiently low-energy level. In this work, an artificial neural network model was used to solve the problem of separation at low-energy levels. The supervised machine learning (ML) model was used to analyse pulses received from the polyethylene naphthalate (PEN) scintillation detector. Several data sets after the PEN exposure to neutron/gamma (combined 239PuBe and 238PuBe source), alpha (238Pu) and beta (90Sr/90Y) sources were used to train the models. The information obtained from the separation of neutrons and gamma particles was compared with the information obtained using standard pulses delayed fluorescence analysis methods. The obtained results showed that the model was able to separate particles in the fields of low- and high-energy transfer.

Influence of cross-section shape on energy harvesting from transverse flow-induced vibrations of bluff bodies

Hydroelastic experiments have been carried out in a free surface water channel to study the influence of the cross-section shape on the mechanical energy transfer from a uniform flow to a self-excited crossflow oscillating prism. Seventeen cross-section shapes were tested with the same mechanical properties (say, mass ratio and mechanical damping) and aspect ratio. Then, the study was focused on the role of the cross-section shape and reduced velocity on the prism dynamics and energy transfer from the fluid flow. It has been found that the geometric centroid of the semi-cross-section and the afterbody length of the cross-section represent a simple and effective metric to characterise the energy transfer. Two related dimensionless geometric parameters are introduced. The dependence of the energy transfer with these two parameters is studied and used to design successfully ‘in advance’ cross-section shapes with high energy transfer efficiencies. It has been observed from particle image velocimetry measurements that large energy transfer shapes are those in which, under strong oscillations, the flow follows the cross-section contour of one side and is fully detached on the other side.

Rapid and ultrasensitive detection of SARS-CoV-2 spike protein based on upconversion luminescence biosensor for COVID-19 point-of-care diagnostics

Here, we firstly introduce a detection system consisting of upconversion nanoparticles (UCNPs) and Au nanorods (AuNRs) for an ultrasensitive, rapid, quantitative and on-site detection of SARS-CoV-2 spike (S) protein based on Förster resonance energy transfer (FRET) effect. Briefly, the UCNPs capture the S protein of lysed SARS-CoV-2 in the swabs and subsequently they are bound with the anti-S antibodies modified AuNRs, resulting in significant nonradiative transitions from UCNPs (donors) to AuNRs (acceptors) at 480 nm and 800 nm, respectively. Notably, the specific recognition and quantitation of S protein can be realized in minutes at 800 nm because of the low autofluorescence and high Yb-Tm energy transfer in upconversion process. Inspiringly, the limit of detection (LOD) of the S protein can reach down to 1.06 fg mL−1, while the recognition of nucleocapsid protein is also comparable with a commercial test kit in a shorter time (only 5 min). The established strategy is technically superior to those reported point-of-care biosensors in terms of detection time, cost, and sensitivity, which paves a new avenue for future on-site rapid viral screening and point-of-care diagnostics.

Novel Design of 0D Nanoparticles-2D Transition-Metal Dichalcogenides Heterostructured Devices for High-Performance Optical and Gas-Sensing Applications

Two-dimensional Transition metal dichalcogenides (TMDCs), have now attracted much attention due to their unique layered structure and physical properties. Up to date, several studies have demonstrated monolayered and few-layered TMDC-based photodetectors with good stability, photo-switching time and broadband detectivity from UV to infrared light region. However, the reported responsivity is not as high as the theoretical expectation, indicating that the light absorption is limited by the atomic thickness of 2D-TMDCs and could still be improved. To overcome the drawback of low absorption in 2D TMDC materials, previous reports have revealed several strategies to enhance the electric field and light-harvesting in these atomically thin TMDC layers by hybridizing plasmonic noble-metal nanoparticles, such as Pt, Au and Ag, to facilitate the light-matter interaction at the surface of semiconductors. In this regard, we aim to combine highly absorptive CuInS2(CIS) nanocrystals with noble metal nanoparticles as the photosensitizer to enhance the intrinsic absorptivity and promote the performance of MoS2-based photodetectors. The interests of noble nanocrystals such as platinum and gold are featured for their distinctive properties of the carrier transportation and the storage when combined with semiconductor materials. The strategy described here acts as a perspective to significantly improve the performance of MoS2-based photodetectors with outstanding detection responsivity with selectable wavelengths by further controlling the size and material of the decorated CIS nanocrystals.In addition to optical sensing, TMDCs have also been developed as a promising candidate for gas-molecule detection. Different from commercial metal oxide gas sensors, TMDCs as sensing materials can be operated at room temperature with good performance, increasing its reliability for future industrial applications. Nevertheless, the relatively low response and long response/recovery time are the main drawbacks of these promising devices. Therefore, we proposed the approach to successfully increase the surface area of TMDCs by a one-step synthesis from WO3 into three-dimensional (3D) WS2 nanowalls through a rapid heating and rapid cooling process. Moreover, the combination of CdS/ZnS or CdSe/ZnS core/shell quantum dots (QDs) with different emission wavelengths and WS2 nanowalls will further improve the performance of WS2-based photodetector devices, including 3.5~4.7 times photocurrent enhancement and shorter response time. The remarkable results of the QD-WS2 hybrid devices to the high non-radiative energy transfer (NRET) efficiency between QDs and our nanostructured material are caused by the spectral overlap between the emission of QDs as the donors and the absorption of WS2 as the acceptors. Additionally, the outstanding NO2 gas-sensing properties of QDs/WS2 devices were demonstrated with a remarkably low detection limit down to 50 ppb with a fast response time of 26.8 s, contributed by tremendous local p-n junctions generated from p-type WS2 nanowalls and n-type CdSe-ZnS QDs in this hybrid system.Our strategies to combine 0D nanoparticles or quantum dots and 2D TMDC materials can significantly enhance the optical sensing and gas molecule sensing properties compared to pristine TMDC-based devices, resulting from the efficient charge or energy transfer between the multi-dimension material system and the creation of local p-n junctions. Moreover, the scalability of these hybrid nanostructures allows our devices to exhibit much more possibilities in advanced multifunctional applications.

First Principles Study of Photocatalytic Reduction of CO2 to CH4 on WS2-Supported Pt Clusters

CO2 conversion into valuable chemicals and fuels is a sustainable route to the concurrent mitigation of the energy crisis and the greenhouse effect. Herein, first principles calculations were employed to study the photocatalytic CO2 reduction over pristine WS2, S-vacancy WS2, and Pt cluster loaded WS2. Our results indicate that the introducing of S-vacancy and loading of Pt clusters can improve the optical absorption in the visible-light region. Furthermore, S-vacancy can lower the barrier (by about 0.17 eV) for *COOH intermediate formation. For Pt/WS2, the strong metal–support interaction is confirmed by high adsorption energy and charge transfer. Importantly, the electron-rich Pt cluster promotes *CO intermediates to facilitate the formation of *CHO intermediates and to further protonate to CH4. This study provides some useful insights into designing the catalysts for the reduction of CO2 and further widens the applications of WS2-based catalytic materials.

Artificial light-harvesting systems based on self-assembled fluorescent palladium(II)-metallacycle in aqueous solution

Light harvesting is one of the fundamental steps in photosynthesis, and developing artificial light harvesting systems (LHSs) with high energy transfer efficiency is still a challenging task. Herein, we designed and constructed a novel fluorescent tetragonal Pd(II)-metallacycle (DDPH-Pd) as a new platform for the construction of artificial LHSs. 6,15-bis(pyridine)-9,12-bis(dodecyloxy)-substituted benzo[5]helicene (DDPH) and ethylenediamine palladium nitrate were coordinated to generate self-assembled DDPH-Pd. Carmosine and Nile red were chosen as acceptors due to their good spectral overlap with that of DDPH-Pd, which is essential for fabricating light-harvesting system. The artificial LHSs show good energy transfer efficiency (61%) and antenna efficiency (5.0) in Carmosine@DDPH-Pd with a 50:1 donor/acceptor ratio.

Spectral function for He4 using the Chebyshev expansion in coupled-cluster theory

We compute spectral function for $^{4}\mathrm{He}$ by combining coupled-cluster theory with an expansion of integral transforms into Chebyshev polynomials. Our method allows us to estimate the uncertainty of spectral reconstruction. The properties of the Chebyshev polynomials make the procedure numerically stable and considerably lower in memory usage than the typically employed Lanczos algorithm. We benchmark our predictions with other calculations in the literature and with electron-scattering data in the quasi-elastic peak. The spectral function formalism allows one to extend ab initio lepton-nucleus cross sections into the relativistic regime. This makes it a promising tool for modeling this process at higher-energy transfers. The results we present open the door for studies of heavier nuclei, important for the neutrino oscillation programs.

Crystal structure and temperature sensing performance of the novel Sr2Y8(1-x-y)(SiO4)6O2:xCe3+,yTb3+ thermometric phosphors

For the research of the thermometric performance, a series of Sr2Y8(1-x-y) (SiO4)6O2:xCe3+,yTb3+ phosphors were synthesized with the solid-state reaction method at N2/H2 atmosphere. The crystal structure, room and high temperature photoluminescence spectra, luminescence decay, CIE variation, energy transfer and thermometric performance have been investigated. With the ultraviolet light excitation, both the Ce3+ broadband spectrum and Tb3+ line spectra have been observed. With the increase of the Tb3+ concentration, the emission color chromaticity varies from dark blue to bright green for the series of Sr2Y8(1–0.07-y)(SiO4)6O2:0.07Ce3+,yTb3+ phosphors. Under high temperature, the Ce3+ emission intensity quenches faster than that of Tb3+. Based on the different temperature quenching speeds of Ce3+ and Tb3+, the fluorescence intensity ratio technique was used to evaluate the thermometric performance of the series of Sr2Y8(1–0.07-y) (SiO4)6O2:0.07Ce3+,yTb3+ phosphors. During the temperature range of 298–498 K, the maximum relative sensitivity values of the phosphors of yTb = 0.05, 0.08, 0.1, 0.15, 0.2, 0.25 were calculated as 0.65, 0.69, 0.74, 0.71, 0.66, 0.6% K−1, which are much better than the recommended value of 0.30% K−1 for the practical application. The physical mechanisms for the Ce3+/Tb3+ excitation and emission, energy transfer and temperature quenching have been discussed. Sr2Y8(1-x-y) (SiO4)6O2:xCe3+,yTb3+ phosphors are the candidate thermometric probes for the non-contact temperature sensing applications.

Electrochemiluminescence Systems for the Detection of Biomarkers: Strategical and Technological Advances.

Electrochemiluminescence (ECL)-based sensing systems rely on light emissions from luminophores, which are generated by high-energy electron transfer reactions between electrogenerated species on an electrode. ECL systems have been widely used in the detection and monitoring of diverse, disease-related biomarkers due to their high selectivity and fast response times, as well as their spatial and temporal control of luminance, high controllability, and a wide detection range. This review focuses on the recent strategic and technological advances in ECL-based biomarker detection systems. We introduce several sensing systems for medical applications that are classified according to the reactions that drive ECL signal emissions. We also provide recent examples of sensing strategies and technologies based on factors that enhance sensitivity and multiplexing abilities as well as simplify sensing procedures. This review also discusses the potential strategies and technologies for the development of ECL systems with an enhanced detection ability.

A novel solar-driven water and electricity cogeneration integrated system by multistage vaporization enthalpy recycling

Satisfied the long-term demand for electricity and freshwater shortage in off grid and resource constrained areas through clean energy is particularly important in the context of comprehensive clean and green development. In this paper, a novel solar-driven freshwater-electricity cogeneration system was proposed, which has high efficiency solar-thermal-electrical conversion capability and outstanding thermal management performance. First, a solar-thermal-electrical coupling numerical model of the system was established, the energy transmission and transformation mechanism were analyzed, and the structural parameters such as the air gap and distillation stages were optimized to further improve the performance of the system. Second, guided by theoretical modeling, the outdoor experiment verified the outstanding thermal management performance through evaporative cooling of seawater and the efficient solar-electricity-steam conversion ability of the system. A photovoltaic module temperature was reduced to about 8 °C, as compared to the same photovoltaic module working alone. And the reduced photovoltaic module temperature led to a 0.86 % increase in average solar-electricity conversion efficiency. Meanwhile, a large amount of freshwater was obtained by consuming the waste heat of photovoltaic modules. The average water production rate was about 2.06 kg·m−2·h−1 under the real outdoor environment. Finally, the system has a stable self-cleaning ability without solid salt crystallization and efficient seawater desalination performance in freshwater production. Hence, this novel system not only realizes passive high energy transfer efficiency to produce freshwater and electricity, but also provides a strategy to solve the crisis of energy and water resources in the future.

Simulation Study of Single-Event Burnout Reliability for 1.7-kV 4H-SiC VDMOSFET

A single-event burnout (SEB) reliability and hardening method for 1.7-kV 4H-SiC power VDMOSFET under high liner energy transfer (LET) value range is proposed and researched by the 2-D numerical simulation. Compared with the conventional VDMOSFET with N-type multi-buffer layers, the hardened VDMOSFET not only ensures that the forward conduction capability does not deteriorate, but also reduces the peak electric field under breakdown voltage from 3.62 MV/cm to 2.98 MV/cm. The advantage of the hardened structure is providing a hole leakage path and increasing the contact area between the source metal and the N+ source, eliminating the effect of electron-hole pairs generated by heavy ion strike on the device, thus improving the SEB performance significantly. In addition, this fabricating technology is compatible with the current technological processes. This hardened structure provides a great potential in aerospace application.

A research on the easy-to-use energy efficiency performance indicators for energy audit and energy monitoring of industrial compressed air systems

Compressed air systems have a high energy transfer capacity. They are widely used in the manufacturing industry due to being clean, dependable, and simple-to-use. On the other hand, these systems are among the most significant energy consumers in the manufacturing sector because they are inefficient with high electricity usage and high CO2 emissions. As a result, all kinds of the energy efficiency enhancements in these systems promote cleaner production by lowering total energy consumption and CO2 emissions in factories. In this paper, the energy-saving potential and carbon emissions of Compressed Air Systems are investigated using data from in-situ energy audits. A simple set of equations is proposed to calculate the mass flow rate of air leakage. The sound intensity (dB) obtained from ultrasonic flow measurements were used as the input of the equation set. Furthermore, two new Energy Performance Indicators have been proposed to guide energy audit evaluation and continuous monitoring of the energy efficiency of Compressed Air Systems in industrial facilities. The new evaluation criteria “Specific Compressed Air Savings” and “Specific Leakage Savings” provide a comparison tool to help decision-makers with their compressed air system investment decisions. Using the “Specific Compressed Air Savings” and “Specific Leak Savings” parameters, the analysis method is demonstrated for an example industrial plant. The facility's specific compressed air and leakage savings are calculated as 0.0067 TOE/ton and 0.0035 TOE/ton, respectively.

Environment-Assisted Modulation of Heat Flux in a Bio-Inspired System Based on Collision Model.

The high energy transfer efficiency of photosynthetic complexes has been a topic of research across many disciplines. Several attempts have been made in order to explain this energy transfer enhancement in terms of quantum mechanical resources such as energetic and vibration coherence and constructive effects of environmental noise. The developments in this line of research have inspired various biomimetic works aiming to use the underlying mechanisms in biological light harvesting complexes for the improvement of synthetic systems. In this article, we explore the effect of an auxiliary hierarchically structured environment interacting with a system on the steady-state heat transport across the system. The cold and hot baths are modeled by a series of identically prepared qubits in their respective thermal states, and we use a collision model to simulate the open quantum dynamics of the system. We investigate the effects of system-environment, inter-environment couplings and coherence of the structured environment on the steady state heat flux and find that such a coupling enhances the energy transfer. Our calculations reveal that there exists a non-monotonic and non-trivial relationship between the steady-state heat flux and the mentioned parameters.

Global dynamics for a class of tristable system with negative stiffness

Tristable system with negative stiffness has attracted extensive attention in the low frequency vibration isolation and vibration energy harvester. As a low frequency vibration isolator, it can achieve high static stiffness and low dynamic stiffness. As a vibration energy harvester, it had a wider bandwidth for resonance than the bistable one. The introduction of negative stiffness may induce subharmonic resonance and chaos in the tristable system. Chaos usually brings disorder to mechanical vibration system. Subharmonic resonance plays the negative effect on low frequency vibration isolation because they will transfer the high frequency energy of the system to the low frequency, but it is beneficial to broaden the working frequency band of vibration energy harvester. In this paper, the subharmonic bifurcation and chaos of a class of tristable system with negative stiffness are studied. The piecewise linearized systems are established to approximate the system with tristable potential. In order to conduct Melnikov analysis, the homoclinic-heteroclinic orbits and periodic orbits for the unperturbed piecewise linearized system are obtained respectively. The subharmonic Melnikov method for nonsmooth systems with four switched manifolds is developed. The thresholds for homoclinic-heteroclinic chaos and subharmonic resonance are derived by using non-smooth Melnikov method. It provides a theoretical support not only for design of the vibration energy harvester to obtain wider working frequency band, but also for design of the vibration isolation system to avoid high frequency energy transfer to low frequency. Moreover, the phenomena for infinite subharmonic bifurcations to chaos from odd order subharmonic orbit and the coexistence for chaotic and subharmonic attractors are revealed. The subharmonic Melnikov method with four switching manifolds developed in this paper lays a foundation for the subharmonic resonance analysis of other nonsmooth tristable systems.

Investigating the effect of different tool electrodes in electric discharge drilling of Waspaloy on process responses

Despite the wide application of electric discharge machining in the fabrication of holes in difficult-to-cut materials, the process's performance and accuracy are governed by the choice of an appropriate tool material and process parameters. Moreover, the process becomes less productive due to unstable machining and inadequate debris flushing while drilling high aspect ration holes, resulting in a low material removal rate (MRR) and high average surface roughness (Ra). Further, the holes' accuracy deteriorates due to a high tool wear rate (TWR). To overcome these issues, a rotary tool electrode setup is proposed for the drilling of Waspaloy. The influence of three different tool materials, viz. copper, brass, and graphite, along with various process parameters, was studied on the process performance. The electrical discharge drilling (EDD) operation was performed by varying the input process parameters, viz. current (I), pulse-on-time (TON), pulse-off-time (TOFF), tool electrode speed (TES), and voltage (V), using copper, brass, and graphite tool electrodes. The influence of machining conditions was investigated on response variables, namely, Ra, TWR, and MRR. Taguchi-based L16 orthogonal array was used to design the experiments, and results were analysed using Analysis of Variance (ANOVA). An improvement in the performance of rotary EDD was observed due to proper flushing, efficient debris evacuation, and steady machining condition. The current was found to be the most significant electrical parameter. The graphite tool electrode had shown the highest MRR of 32.056 mm3/min at 25 A current which was 13.09% and 131.32% higher than that of the copper and brass tool electrodes, respectively. However, the graphite tool resulted in a poor surface quality, and a high energy transfer coefficient, indicating the highest Ra value of 8.385 μm. The brass tool electrode, owing to a lower thermal conductivity and melting point, caused a higher TWR than the copper and graphite tools. Finally, the microscopic images for drilled holes with different electrodes at various energy settings were captured using field emission scanning electron microscopy (FESEM) and compared for surface quality. In addition, the surface elemental analysis was performed using Energy Dispersive X-Ray Analysis (EDX) to investigate material migration from the tool electrodes to hole's side walls.

The Fragility Fracture Postoperative Mobilisation multicentre audit : the reality of weightbearing practices following operations for lower limb fragility fractures.

The purpose of this study was to determine the weightbearing practice of operatively managed fragility fractures in the setting of publically funded health services in the UK and Ireland. The Fragility Fracture Postoperative Mobilisation (FFPOM) multicentre audit included all patients aged 60 years and older undergoing surgery for a fragility fracture of the lower limb between 1 January 2019 and 30 June 2019, and 1 February 2021 and 14 March 2021. Fractures arising from high-energy transfer trauma, patients with multiple injuries, and those associated with metastatic deposits or infection were excluded. We analyzed this patient cohort to determine adherence to the British Orthopaedic Association Standard, "all surgery in the frail patient should be performed to allow full weight-bearing for activities required for daily living". A total of 19,557 patients (mean age 82 years (SD 9), 16,241 having a hip fracture) were included. Overall, 16,614 patients (85.0%) were instructed to perform weightbearing where required for daily living immediately postoperatively (15,543 (95.7%) hip fracture and 1,071 (32.3%) non-hip fracture patients). The median length of stay was 12.2 days (interquartile range (IQR) 7.9 to 20.0) (12.6 days (IQR 8.2 to 20.4) for hip fracture and 10.3 days (IQR 5.5 to 18.7) for non-hip fracture patients). Non-hip fracture patients experienced more postoperative weightbearing restrictions, although they had a shorter hospital stay. Patients sustaining fractures of the shaft and distal femur had a longer median length of stay than demographically similar patients who received hip fracture surgery. We have shown a significant disparity in weightbearing restrictions placed on patients with fragility fractures, despite the publication of a national guideline. Surgeons intentionally restrict postoperative weightbearing in the majority of non-hip fractures, yet are content with unrestricted weightbearing following operations for hip fractures. Cite this article: Bone Joint J2022;104-B(8):972-979.