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This paper presents experimental and numerical analysis results regarding the effects of an incomplete penetration defect on the fatigue lives of socket welded pipes. For the experiment, four-point bending fatigue tests with various defect geometries (defect depth and circumferential length) were performed, and test results are presented in terms of stress-life data. The results showed that for circumferentially short defects, the fatigue life tends to increase with increasing crack depth, but for longer defects, the trend becomes the opposite. Finite element analysis showed that for short defects, the maximum principal stress decreases with increases in crack depth. For a longer defect, the opposite trend was found. Furthermore, the maximum principal stress tends to increase with an increase in defect length regardless of the defect depth.

In this paper, we report on a new dielectric, a C60-containing block polyimide (PI-b-C60). This was realized by introducing C60 as pendent groups into a polymer backbone. When this dielectric was used in a non-contact mode triboelectric nanogenerator (TENG), it achieved high output power and reliable operation. Compared with perfluoroalkoxy alkane film-based TENGs, the TENG based on PI-b-C60 generated 4.3 times higher output power and a superior charge density of over 300 μC m−2 with a 3 times slower charge decay rate. These results are most likely due to the excellent charge-retention characteristics induced by the most negative electrostatic potential of C60 within the backbone, and these characteristics were confirmed by surface potential measurements. Furthermore, in the course of our work, two non-contact mode applications, a keyless electronic door lock system and a speed sensor with a tone wheel for a car, were developed. Without an ion injection process being needed, very sensitive and reliable operations of the speed sensor were successfully demonstrated, even under very humid conditions (∼99% RH).

This work introduces, for the first time, the energy harvesting performance of conjugated microporous polymers (CMPs) as tribo-positive materials for triboelectric nanogenerators (TENGs). Various nano or submicron CMP particles (CMP-X) were prepared by the Sonogashira coupling of 1,3,5-triethynylbenzene with 1,4-diiodoarenes. Optimized CMP-X nanoparticles in a polyurethane (PU) matrix showed excellent triboelectrification performance, displaying peak-to-peak voltages of up to 411 V and a maximum power density of 0.80 mW cm−2. Moreover, an optimized 5.0% CMP-H@PU-based TENG could be utilized as a power source for the charging of an electrolytic capacitor and for the operation of 100 LEDs.

Transition-metal phosphide (TMP) nanostructures have been extensively studied for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). However, phase-controlled synthesis of collo...

peer-reviewed The full text of this article will not be available in ULIR until the embargo expires on the 10/03/2021 Here, a three-dimensional (3D) core–shell nanohybrid based on few-layer amorphous Co–Fe–Bi nanosheets directly grown on crystalline NiCo2O4 nanowires supported on the Ni foam (Co–Fe–Bi/NiCo2O4/NF) are facilely fabricated as highly efficient and durable electrocatalysts for water oxidation. This self-standing 3D core–shell nanohybrid design with unique materials chemistry and excellent interface engineering enhances the mass transport and stimulates the production of active sites during the oxygen evolution reaction. Serving as the anode catalysts, the resulting self-standing Co–Fe–Bi/NiCo2O4/NF nanohybrid electrocatalysts show a better electrocatalytic activity with an overpotential of 227 mV at 10 mA/cm2, a Tafel slope of 45 mV dec–1, excellent durability over 40 h, and the ability to deliver a current density of 200 mA/cm2 at an overpotential of ∼410 mV in an alkaline medium. Thus, the excellent electrocatalytic performance of the Co–Fe–Bi/NiCo2O4/NF nanohybrid demonstrates the importance of design and development of core–shell nanohybrids for large-scale practical applications in a multitude of energy conversion devices.

Due to its favorable optical properties, Cu2SnS3 (CTS) is a promising material for thin film solar cells. Doping, which modifies the absorber properties, is one way to improve the conversion efficiency of CTS solar cells. In this work, CTS solar cells with selenium doping were fabricated on a flexible substrate using sputtering method and the effect of doping on the properties of CTS solar cells was investigated. In XRD analysis, a shift in the CTS peaks can be observed due to the doped selenium. XRF analysis confirmed the different ratios of Cu/Sn and (S+Se)/(Cu+Sn) depending on the amount of selenium doping. Selenium doping can help to lower the chemical potential of sulfur. This effectively reduces the point defects of CTS thin films. Overall improved electrical properties were observed in the CTS solar cell with a small amount of selenium doping, and a notable conversion efficiency of 1.02 % was achieved in the CTS solar cell doped with 1 at% of selenium.

Description, The ultrasound-mediated transient materials enable the management of biodegradation processes for implantable electronics., On-demand transient electronics, technologies referring subsequent material disintegration under well-defined triggering events and programmed time lines, offer exceptional clinical experiences in diagnosis, treatment, and rehabilitation. Despite potential benefits, such as the elimination of surgical device removal and reduction of long-term inimical effects, their use is limited by the nontransient conventional power supplies. Here, we report an ultrasound-mediated transient triboelectric nanogenerator (TENG) where ultrasound determines energy generation and degradation period. Our findings on finite element method simulation show that porous structures of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) play an essential role in the triggering transient process of our device under high-intensity ultrasound. Besides, the addition of polyethylene glycol improves triboelectric output performance; the voltage output increased by 58.5%, from 2.625 to 4.160 V. We successfully demonstrate the tunable transient performances by ex vivo experiment using a porcine tissue. This study provides insight into practical use of implantable TENGs based on ultrasound-triggered transient material design.

The development of nanostructured architectures using low-cost first–row transition metals with high electrocatalytic activity to replace noble-metal-based electrocatalysts has recently gained considerable attention in the field of clean and sustainable energy generation technology. In this study, highly efficient, binder-free, Ni–Co layered double hydroxide (NiCo-LDH) nanowires on a nickel foam (NF) substrate were fabricated via a simple, one-step hydrothermal synthesis procedure, and their use as electrocatalysts for the oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) was studied. When NiCo-LDH was used as the OER electrocatalyst, the overpotential required to deliver a current density of 20 and 100 mA cm−2, was only 270 and 410 mV (without iR correction), and it exhibited a long-term stability of 50 h in 1 M KOH. Moreover, the as-prepared NiCo-LDH nanowire electrocatalyst presented remarkable electrochemical performance for the MOR with a higher current density of 761 mA cm−2 at 0.7 V vs. the saturated calomel electrode (SCE) and excellent stability in 1 M KOH with 0.5 M methanol. The vertically aligned NiCo-LDH nanowires presented numerous active sites and open structures and their synergism with the highly conductive NF substrate was responsible for the excellent electrochemical performance of the electrocatalyst.

The triboelectric effect is a ubiquitous phenomenon in which the surfaces of two materials are easily charged during the contact‐separation process. Despite the widespread consequences and applications, the charging mechanisms are not sufficiently understood. Here, the authors report that, in the presence of a strain gradient, the charge transfer is a result of competition between flexoelectricity and triboelectricity, which could enhance charge transfer during triboelectric measurements when the charge transfers of both effects are in the same direction. When they are in the opposite directions, the direction and amount of charge transfer could be modulated by the competition between flexoelectric and triboelectric effects, which leads to a distinctive phenomenon, that is, the charge transfer is reversed with varying forces. The subsequent results on the electrical power output signals from the triboelectrification support the proposed mechanism. Therefore, the present study emphasizes the key role of the flexoelectric effect through experimental approaches, and suggests that both the amount and direction of charge transfer can be modulated by manipulating the mixed triboelectric and flexoelectric effects. This finding may provide important information on the triboelectric effect and can be further extended to serve as a guideline for material selection during a nanopatterned device design., Using experimental approaches, the authors show that, in the presence of strain gradient, the charge transfer during triboelectric measurements is resulted from competition between flexoelectricity and triboelectricity. The charge transfer can be enhanced or inversed depending on the relative charge transfer direction of both effects. This finding could be a guideline for material selection for a nanopatterned device design.

The synthesis of earth-abundant, low-cost, and stable electrocatalysts with high efficiency in the oxygen evolution reaction (OER) is a necessary requirement for improving the effectiveness of electrochemical water splitting approach. To date, expensive electrode materials and time-consuming synthesis procedures have generally been used for the electrocatalysts applied in water splitting, which limits their efficiency. Herein, nickel-iron oxyhydroxide nanosheets are fabricated by a scalable and ultrafast (requiring only 5 s) wet chemical strategy on a nickel foam substrate. The experimental results indicate that compared to recently reported catalysts, the prepared nickel-iron oxyhydroxide electrode has a high number of active sites and low reaction barrier, enabling efficient OER catalysis in an alkaline electrolyte. In particular, the prepared nickel-iron oxyhydroxide electrode requires an ultralow overpotential of 230 mV to reach a current density of 50 mA cm−2, with excellent long-term stability for 75 h. Moreover, the nickel-iron oxyhydroxide also performs well towards the electrocatalytic urea oxidation reaction (UEOR), with a very low potential of 1.38 and 1.41 V vs RHE (reversible hydrogen electrode) to reach 50 and 100 mA cm−2 current density in 1 M KOH with 0.33 M urea electrolyte. This ultrafast synthesis approach can be extended to prepare electrocatalysts used for other electrochemical reactions.

Contaminated drinking water is one of the main pathogen transmission pathways making waterborne illnesses such as diarrheal diseases and gastroenteritis a huge threat to public health, especially in the areas where sanitation facilities and gird power are inadequate such as rural and disaster hit areas. Self-powered water disinfection systems are a promising solution in these cases. In this review paper, the authors provide an overview of the new and emerging methods of applying energy harvesting materials and devices as a source of power for water disinfection systems microbial disinfection in water by harnessing ambient forms of energy such as mechanical motion, light, and heat into electricity. The authors begin with a brief introduction of the different energy harvesting technologies commonly applied in water disinfection; triboelectric, piezoelectric, pyroelectric, and photovoltaic effects. Various microbial disinfection mechanisms and types of device construction are summarized. Then, a detailed discussion of the energy harvester-driven water disinfection process is provided. Finally, challenges and perspectives regarding the future development of self-powered water disinfection are described.

Design and development of efficient and low-cost electrocatalysts for oxygen evolution reaction (OER) remain a challenge due to high overpotential, low stability, and scalability issues. As a realistic solution, herein, amorphous (Co-Mn)S tailored into nanosheets is demonstrated as a highly efficient and stable electrocatalyst for OER. Thin films of (Co-Mn)S are deposited on stainless steel (SS) substrates via a scalable successive ionic layer adsorption and reaction (SILAR) method for the first time. The stoichiometric tuning of composition has effectively augmented the electrocatalytic activity and OER performance by modification of electronic structure and binding strength with the intermediates. The tailored nanosheet like morphology resulted in achieving high current density at low overpotential. Benefited from the synergy of redox chemical properties and a binder-free deposition, (Co3Mn2)S thin film electrocatalyst achieved a current density of 10 mA cm−2 at an overpotential of 243 mV in 1 M KOH electrolyte. On top of that, the electrocatalyst displayed excellent stabilities over 100 h of continuous water oxidation without any apparent change. In view of the simple yet scalable approach of synthesis, and excellent OER performance, amorphous (Co-Mn)S thin film electrocatalyst could be deliberated as a promising candidate for large application of OER.

Photodetectors have large applications in the current ongoing pandemic. These can be used to study the growth of viruses where depending upon the concentration the light intensity will be reduced. Since the viruses grow very fast therefore a device with very low response time as well as quick recovery will be useful for this study. If the device can be made from the non-toxic materials and sizes are quite small, they can be used for in vitro studies as well. Kesterite Cu2ZnSn(S, Se)4 (CZTSSe) thin film can be deposited over flexible substrates. The detectivity of even very small area device is very high with ultra-small response and recovery time. The CZTSSe PD exhibited excellent broadband (Vis-NIR) photoresponse, high responsivity of 18.0 mA.W−1, a fast rise time of 82 ms, and a decay time of 97 ms, as well as high detectivity (∼109 Jones) with favorable self-powered characteristics. This work suggests significant scientific insights for photoconductivity properties of emerging kesterite CZTSSe thin-film materials for broadband, low-cost, high-efficiency next-generation thin-film photodetectors for various optoelectronic applications including diagnostic.

>> Activated charcoal supported nickel molybdenum carbide (carburized Ni-Mo/AC) catalysts were prepared by wet-impregnation followed by temperature-programmed carburization using 20% CH 4 /H 2 gas. The effects of pH and initial Ni/Mo mole ratio during wet-impregnation step on the characteristics of the carburizedNi-Mo/AC catalysts were investigated using ICP, XRD, XPS, BET and CO 2 -TPD techniques, and correlated withthe catalytic activity of the carburized Ni-Mo/AC in methane dry reforming reaction. Comparison of the resultsof methane dry reforming reaction kinetics with the results of characterization of the carburized Ni-Mo/AC catalystshowed that the catalytic activity in methane dry reforming reaction was higher at higher initial Ni/Mo mole ratioor at lower pH(3~natural value). This phenomenon was related to the crystal size of metallic Ni in the carburizedNi-Mo/AC catalyst. Key words : Nickel molybdenum carbide(니켈 몰리브덴 카바이드), Wet-impregnation(습식담지), Carburization(침탄), pH(수소이온농도지수), Initial Ni/Mo mole ratio(초기 Ni/Mo 몰비)

This paper reports the effects on the optical and electrical properties of indium tin zinc oxide (ITZO) films by annealing and hydrogen plasma treatment. ITZO films were prepared by spin-coating using ITZO nanoink. The sheet resistance of the spin-coated ITZO was decreased to 155 Ω/square after annealing at 300 °C. Subsequent inductively-coupled hydrogen plasma decreased the sheet resistance of the ITZO film further to 88 Ω/square due to the formation of a high density of O–H bonds and oxygen vacancies leaving a metal cluster on the surface, which is comparable to that of solution-processed ITO films. Although the transmittance of the hydrogen plasma-treated sample was decreased considerable by the formation of metal clusters, the transmittance and optical band gap could be enhanced without a deteriorating the electrical properties by removing the metal clusters using a H 2 SO 4 solution.

A 5 kg/hr scale integral dual fluidized-bed gasifier for producing medium heating value syngas from biomass or combustible wastes was manufactured. The effect of operating variables including gasification temperature, rate of feeding, and weight ratio of steam/feed on the behavior of the gasifier was investigated. The contents of H2 and CO in syngas, flow rate of feeding, cold gas efficiency increased with the increased gasification temperature or rate of feeding, but decreased with the increased weight ratio of steam/feed within the experimental range. With wood powder as the feed, the concentrations of H2 and CO in the syngas were as high as 41% and 32%, and the cold gas efficiency and lower heating value of the syngas were as high as 70.1% and 3,428 kcal/Nm 3 . With food wastes as the feed, the concentrations of H2 and CO in the syngas were as high as 37% and 23.9%, and the cold gas efficiency and lower heating value of the syngas were as high as 66.7% and 3,670 kcal/Nm 3 .

The electrical properties of Ni-based ohmic contacts to N-face p-type GaN were investigated. The specific contact resistance of N-face p-GaN exhibits a linear decrease from 1.01 omega cm2 to 9.05 x 10(-3) omega cm2 for the as-deposited and the annealed Ni/Au contacts, respectively, with increasing annealing temperature. However, the specific contact resistance could be decreased down to 1.03 x 10(-4) omega cm2 by means of surface treatment using an alcohol-based (NH4)2S solution. The depth profile data measured from the intensity of O1s peak in the X-ray photoemission spectra showed that the alcohol-based (NH4)2S treatment was effective in removing the surface oxide layer of GaN.

This study examined the effects of H2 and H2 + O2 mixed gas plasma treatment on the properties of ITO films. The films were deposited on corning glass by RF magnetron sputtering under Ar and Ar/O2 mixed gas ambient. After a H2 plasma treatment, the ITO films showed an improved specific resistance due to the formation of oxygen vacancies acting as shallow donors, but showed quenched transmittance due to the formation of agglomerated metals on the surface. After an H2 + O2 mixed gas plasma treatment, the specific resistance of the film was improved without deteriorating transmittance. The enhanced specific resistance by mixed gas plasma treatment was attributed to the formation of free electrons by the incorporation of H in the lattice.

The silver-palladium(Ag-Pd) alloy coating as a solid lubricant was investigated for its application to the high temperature stud bolts used in nuclear power plants. A hex bolt sample was prepared in the following steps: 1) bolt surface treatment using alumina grit blasting for cleaning and increasing the surface area; 2) nickel(Ni) film coating as a glue layer on the surface of the bolt; and 3) Ag-Pd alloy coating on the Ni film. The films were deposited by using a direct current(DC) magnetron sputtering system. The thickness and composition of the Ag-Pd alloy film have effect on the friction coefficient, which was determined using axial force measurement. A 500 nm-thick Ag-Pd (80:20, molar ratio) alloy film has the lowest friction coefficient of 0.109. A cyclic test was conducted to evaluate the durability of bolts coated with either the Ag-Pd (80:20) alloy film or N-5000 oil. In a cycle, the bolts were inserted into a block using a torque wrench, which was followed by heating and disassembling. After only one cycle, it was not possible to remove the bolts coated with the N-5000 oil from the block. However, the bolts coated with the Ag-Pd (80:20) alloy could be easily removed up until 15 cycles.

Heterotaxy, a birth defect involving left-right patterning defects, and primary ciliary dyskinesia (PCD), a sinopulmonary disease with dyskinetic/immotile cilia in the airway are seemingly disparate diseases. However, they have an overlapping genetic etiology involving mutations in cilia genes, a reflection of the common requirement for motile cilia in left-right patterning and airway clearance. While PCD is a monogenic recessive disorder, heterotaxy has a more complex, largely non-monogenic etiology. In this study, we show mutations in the novel dynein gene DNAH6 can cause heterotaxy and ciliary dysfunction similar to PCD. We provide the first evidence that trans-heterozygous interactions between DNAH6 and other PCD genes potentially can cause heterotaxy. DNAH6 was initially identified as a candidate heterotaxy/PCD gene by filtering exome-sequencing data from 25 heterotaxy patients stratified by whether they have airway motile cilia defects. dnah6 morpholino knockdown in zebrafish disrupted motile cilia in Kupffer’s vesicle required for left-right patterning and caused heterotaxy with abnormal cardiac/gut looping. Similarly DNAH6 shRNA knockdown disrupted motile cilia in human and mouse respiratory epithelia. Notably a heterotaxy patient harboring heterozygous DNAH6 mutation was identified to also carry a rare heterozygous PCD-causing DNAI1 mutation, suggesting a DNAH6/DNAI1 trans-heterozygous interaction. Furthermore, sequencing of 149 additional heterotaxy patients showed 5 of 6 patients with heterozygous DNAH6 mutations also had heterozygous mutations in DNAH5 or other PCD genes. We functionally assayed for DNAH6/DNAH5 and DNAH6/DNAI1 trans-heterozygous interactions using subthreshold double-morpholino knockdown in zebrafish and showed this caused heterotaxy. Similarly, subthreshold siRNA knockdown of Dnah6 in heterozygous Dnah5 or Dnai1 mutant mouse respiratory epithelia disrupted motile cilia function. Together, these findings support an oligogenic disease model with broad relevance for further interrogating the genetic etiology of human ciliopathies., Author Summary Heterotaxy is a birth defect involving randomization of left-right body axis. Its genetic etiology is still poorly understood, but recent studies suggest mutations in genes causing primary ciliary dyskinesia (PCD), a sinopulmonary disease, also can cause heterotaxy. Moreover, heterotaxy patients can show airway cilia dysfunction reminiscent of PCD. The link between these two seemingly disparate diseases reflects the common requirement for motile cilia in both left-right patterning and airway mucus clearance. Sequencing analysis of heterotaxy patients together with experimental modeling identified DNAH6 as a novel gene that can cause both heterotaxy and PCD. We further showed DNAH6 can interact with other PCD genes to mediate a more complex oligogenic etiology of disease. Thus experimental modeling with double gene knockdown showed digenic interactions of DNAH6 with DNAH5 or DNAI1 could disrupt motile cilia function in the respiratory epithelia and also cause heterotaxy in zebrafish embryos. These findings provide the first experimental evidence indicating oligogenic interactions can contribute to the complex genetics of heterotaxy.

Vibration characteristics of stiffened laminated plates are investigated considering postbuckled deflection effect due to thermal load. The finite element method is used for the analysis of thermal postbuckling and natural vibration of stiffened plates in the postbuckling range. The finite element model is based on the first order shear deformable plate theory (FSDT) for a skin panel and Timoshenko beam theory for stiffeners. Von Karman strain-displacement relation is used to account for a large deflection. Critical buckling temperature and the corresponding mode shape are determined from Euler buckling problem. In order to solve the thermal-postbuckling problem, the initial nonlinear stiffness is determined from an estimated deflection of scaled buckling mode shape. The converged deflection at any temperature change is obtained using the Newton-Raphson method. The vibration analyses of stiffened laminated plates in the postbuckling range are performed using the tangent stiffness obtained from the converged deflection. The effects of the stiffener size, the number of stiffeners, and lamination scheme on vibration characteristics are studied for stiffened laminated plates subject to steady-state uniform temperature increase.

Vibration behaviors of thermally postbuckled anisotropic plates are investigated. The finite element method is used for the analysis of thermal postbuckling and natural vibration of thermally postbuckled plates. The finite element model is based on the first-order shear deformable plate theory (FSDT) and von Karman strain-displacement relation to account for large deflection. Critical buckling temperature and the corresponding mode shape are determined from Euler buckling problem. In order to solve the thermal-postbuckling problem, the initial nonlinear stiffness is determined from estimated deflection of scaled buckling mode shape. The converged deflection at any temperature change is obtained using the Newton-Raphson method. The vibration analysis of thermally postbuckled plates are performed using the tangent stiffness obtained from the converged deflection. The effect of fiber orientation angle and aspect ratio on postbuckling and vibration behaviors are studied for simply supported laminated plates subject to steady-state uniform temperature increase.

The analysis of vibration characteristics of anisotropic plates with eccentric stiffeners has been performed using the finite element method based on the shear deformable plate theory. The stiffeners are modeled as a beam element based on Timoshenko beam theory. The present analysis presents the effects of fiber orientation, dimension and location of the stiffener on the vibration characteristics of anisotropic stiffened plates. The stiffened plates are composed of graphite-epoxy(AS1/3501-6) composite laminate with a symmetric stacking sequence. The present finite element model uses nine-node quadrilateral elements for the skin plate and three-node quadratic elements for the stiffener. The solution of the eigenvalue problems has been obtained by the subspace iteration method. The results obtained by the present finite element model are compared with previous results for the stiffened isotropic plates. Also, the result of the present beam model for the stiffener made of composite material is compared with that of the shell model. This result shows that the present model for the stiffened plate gives quite accurate results. The size, fibre orientation angle and location of the stiffener affect the natural frequencies and mode shapes of the stiffened anisotropic plate.

In this study, we examined the characteristics of Ni/Au (20 nm/80 nm) ohmic contacts to non-polar a-plane p-GaN as a function of annealing temperature. The current?voltage (I?V) curves were showed an upward curve with annealing when Ni/Au metals were used as ohmic metals to nonpolar p-GaN, which was similar to those of the other crystalline planes. The contact resistivity decreased from 2.36 to 6.95 ? 10?3 ? cm2. Secondary ion mass spectroscopy showed that the Ga atoms out-diffused from the GaN substrate after annealing at 400 ?C, which led to the generation of Ga vacancies. The formation of Ga and N vacancies was found to be a competing process during annealing.

This study examined the optical and electrical properties of indium tin oxide (ITO) films treated with a hydrogen plasma and a post-HCl solution. ITO films, 200 nm in thickness, were deposited on polyethylene terephthalate (PET) substrates by the radio frequency magnetron sputtering method. The samples were then exposed to an inductively coupled hydrogen plasma and this was followed by HCl : DI solution treatment. The work function of the ITO surface was decreased from 4.94 to 4.61 eV without thermal annealing. The sheet resistance was decreased due to the formation of a high density of O–H bonds and oxygen vacancies. Although the transmittance of the hydrogen-plasma-treated sample was decreased drastically by the formation of In/Sn clusters, enhanced transmittance and increased optical band gap without a deterioration of the electrical properties could be achieved effectively by removing the In/Sn clusters using a HCl solution.