Different Types Of Deformation Research Articles

Mock-up conception for experimentally investigate the creep phenomenon caused by the fluid–structure interaction in a rod bundle

Pressurized water reactors (PWRs) are employed worldwide and continue to expand in capacity. They require thorough investigation, particularly concerning their safety and operational efficiency. To ensure these factors, comprehensive research into their various components and an understanding of the diverse phenomena they experience within a PWR are imperative. These phenomena can be of mechanical, thermal, hydraulic, or neutronic nature. Among these components, fuel assemblies (FAs) hold a main role in PWRs. The intricate interplay of these physical factors results in the modification of FAs geometry, specifically permanent elongation and lateral deformations referred to as irradiation creep. The earliest reported occurrence of these deformations dates back to 1994 in Ringhals reactors, where various FAs exhibited distinct deformations (Andersson et al., 2005). Given that these phenomena occur over a time span of months to years in metallic materials, conducting investigations within the confines of a typical laboratory observation period becomes impractical. Consequently, this project proposes an alternative experimental methodology to overcome this challenge, thus gaining a deeper understanding of the fluency phenomenology in FAs behavior. This methodology consists on the design of a reduced-scale test section, capable of replicating the fluid–structure interaction (FSI) responsible for creep, the creation of spacer grids through 3D printing technology, and selection of the appropriate material for the fuel rods (FRs), with an emphasis on macroscopic coupling effects, rather than focusing into the micro-structural response of the material. To experimentally observe the deformation on the FAs, cameras were used to capture images through the time during the test, to catch the displacement of the FRs. The first results showed the mock-up was able to reproduce the FSI causing the creep on the FAs, it was possible to capture the displacement evolution along time, and to observe different types of deformation, thus, it helps to understand the phenomenon. Further tests and investigations using laser doppler velocimetry (LDV) technique to analyze the flow will be held, to a better comprehension of these burden.

Serpentine liquid electrode based Dual-mode skin Sensors: Monitoring biomechanical movements by resistive or triboelectric mode

Flexible and stretchable electrodes are crucial components for wearable electronic devices. Herein, a serpentine liquid electrode based dual-mode skin sensors (SLEDSS) that leverages a highly deformable and serpentine liquid electrode is developed. The functional carboxylated multi-walled carbon nanotubes / Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (MWCNT-COOH / PEDOT: PSS) network structure endows the SLEDSS with a stable linear change in resistance. Additionally, a solid–liquid double electric layer generated between the solid surface and liquid electrode facilitates a higher triboelectric output performance. As a result, the SLEDSS features dual-modal sensing capabilities, including both resistive and triboelectric modes. The flowability of the liquid electrode enables it to fully adapt to different types of deformation, thereby allowing SLEDSS to effectively collect energy in different forms of movement, such as tapping, stretching, bending, twisting, and unpredictable transformations based on practical applications. SLEDSS can maintain its performance even at up to 550.32% strain, displaying a monotonically increasing relationship between the stretchable length and open-circuit voltage. Finally, the SLEDSS is applied as a wearable power source and self-powered sensor for monitoring biomechanical movements, the excellent stretchable performance and ultra-high sensitivity to mechanical stimulation provided by the SLEDSS offer new prospects for self-powered sensors.

Near-infrared photo-responsive Ti3C2Tx MXene/LCN film for soft actuators

ABSTRACT Soft actuators have attracted a lot of attention because of their impressive performance and wide range of applications. Liquid crystalline networks (LCNs) are a combination of liquid crystals and polymers, and they are considered to be the most promising materials for creating soft actuators. MXene has a high photothermal conversion efficiency, and it can be a heat-source under near-infrared light. In this paper, we fabricated a MXene/LCN composite film by coating a solution of Ti3C2Tx MXene onto an LCN film with orientation direction and then followed by drying. We observed different types of deformations when we cut the composite film in different directions. We also measured the influence of the near-infrared light intensity on the bending angle, response time, and recovery time of the composite films with different deformations. Finally, we used this composite film to fabricate various biomimetic devices such as biomimetic flowers, artificial irises, mechanical fixtures, and crawling robots. These results demonstrate the great potential of this composite film in soft actuator applications.

Application of the method of measuring deformation parameters under mechanical action on concrete beams using a fiber Bragg grating

In order to study the patterns of deformation and change of concrete structures, studies of the fiber Bragg lattice in the form of a measuring sensor were carried out. Fiber optic sensors have several advantages: small size, resistance to electromagnetic interference, high sensitivity, wide range, simple structure, high reaction rate, corrosion resistance, geometrically versatile and resistant to external influences. This work is related to the development of the characteristics and behavior of strain sensors acting on a fiber Bragg lattice using computer modeling. The work focuses on the analysis of the operational characteristics and behavior of strain sensors acting on the fiber Bragg lattice. The sensor is used to measure the deformation of an object whose resistance varies depending on the applied force. This is shown by an example of how a fiber Bragg lattice can demonstrate strain sensors. In the work, a simulation was carried out using a computer program to simulate the operation of a fiber Bragg lattice deformation sensor. When measuring the deformation, calculations with the Young's modulus formulas were used for a more accurate calculation of the data. When measured, the wavelength left from 1662 nm to 1666 nm, as well as a constant temperature from 20 °C to 40 °C. The results show the following, the values of the Young's modulus are 23.25 Pa, the Poisson's ratio is 0.167 br, the modulus of elasticity at shear is 9.96444 Pa. And in this regard, the results of this work show: the first is that changes in the magnitude, position and shape of the deformation can reflect the dynamic evolutionary process of deformation during bending on the structure. The following is the deformation curve has a good corresponding relationship with the change in the applied pressure, which shows software modeling in different types of deformation. The conclusion shows that the technology of monitoring fiber-Bragg lattice sensors has a good effect on internal deformation and control of mechanical stresses during model tests; it provides new methods and monitoring tools for model tests

An adjoint-based drag reduction technique for unsteady flows

A framework based on a continuous adjoint-based analysis of steady and unsteady flows to predict and control the drag force due to surface morphing is presented. By establishing a relation between perturbations in the body shape and in the boundary condition on a certain geometry, we derive an analytical expression of the sensitivity to changes in the geometry of the body and its relation to the sensitivity to the perturbation of the boundary conditions. The methodology is evaluated on the incompressible flow around a cylinder for steady and unsteady flows. A reduction of the drag coefficient was obtained and investigated by several surface deformations, conducted in the direction of the sensitivity vector field obtained by solving the derived adjoint problem. In unsteady flows, the sensitivity field is computed by integrating the unsteady adjoint problem backward in time from the unsteady flow solution. Two different types of deformations based on the calculated sensitivity were applied: time-averaged deformation and time-dependent. Attempting the latter, a deformation at each time step, did not yield the same satisfactory results as the time-averaged in terms of expected drag reduction. We provide a theoretical reasoning for the difference between both methodologies, together with an insight into the physics of the sensitivity vector field distribution relating it to the drag force sources.

Influence of Deformation of Metal Matrix on the Mechanical Properties of Poly(Ethylene Terephthalate) Inside It

The influence of different types of deformation of the metal matrix on mechanical behavior of the amorphous PET film upon its transverse compression in the ductile metal matrix has been investigated. Three deformation modes have been probed. In the first case, a disc-shaped polymer specimen has been put between two 5 mm thick discs of the lead–tin alloy and squeezed in the press. In the second and the third cases, planar elongation has been performed in the so called “dead channel”, i.e., the channel with fixed side walls, the film being elongated due to decrease in the width or thickness, respectively. The plots of true yield stress at different draw ratios have formed a common master curve. At high total draw ratio Λ, the true yield stresses have been close for the considered three types of drawing in the metal. At the draw ratio Λ 2.6, the neck has not appeared, and the specimen has been deformed uniformly. When the film in the channel is elongated due to the decrease in thickness at constant width, the specimen width has been mainly decreased during subsequent elongation in the testing machine. When the film in the channel is elongated due to the decrease in width at constant thickness, further elongation has mainly led to the decrease in the specimen thickness. The true stress Σ has been expressed as Σ = Σ0 + KΛ3, with K being a constant. Deformation of the polymer in the channel occurred with the formation of shear bands. At the preliminary draw ratio Λ = 1.82, the bands have been oriented at the angle 21.5° with respect to the stretching axis. The planar elongation has led to abnormally strong deformation softening of the polymer. The drawing has been accompanied by an increase in the elasticity modulus of the polymer. The obtained results have suggested that the macromolecules orientation is the main reason for strain hardening of the polymer.

Mechanical properties of 2D metal–organic and covalent–organic frameworks with non trivial topological band dispersion

Using density functional theory (DFT), we investigate mechanical properties of a few 2D metal–organic frameworks (MOFs) and covalent–organic frameworks (COFs) having Dirac and flat bands. These porous materials have become a subject of great captivation because of their physical stability, distinctive structural characteristics and large surface to volume ratio. The inherent porosity of these frameworks gives rise to many fascinating and occasionally surprising phenomena, which makes them potential candidates for technological applications. For reliable usage of MOFs/COFs in functional nanodevice and practical application, it is quite imperative to investigate their mechanical properties. Thus, herein a particular attention is paid to study elastic deformation of few 2D MOFs and COFs having non trivial topological band dispersion in the regime with linear dependency of stress upon strain. Specially, we consider different types of deformation and find all the components of elastic tensor from the stress–strain and energy–strain curves. These findings may provide useful information to fabricate the MOFs/COFs based devices by lowering the number of experiments.

Palaeopathological and demographic data reveal conditions of keeping of the ancient baboons at Gabbanat el-Qurud (Thebes, Egypt).

Since predynastic times, baboons (Papio hamadryas and Papio anubis) were important in ancient Egypt for ritual and religious purposes. These species did not occur naturally in Egypt and therefore had to be imported, but little is known about their exact provenance and the conditions in which they were kept through time. Here, we analyse the skeletal remains of a collection of baboon mummies coming from Thebes (Egypt), representing a minimum of 36 individuals, from a palaeopathological and demographic point of view. The pathological cases are described, figured where relevant, and the discussion attempts to understand their aetiology. The prevalence of the different types of deformations and pathologies is compared with that of other captive baboon populations from more or less contemporary (Tuna el-Gebel and Saqqara) or older (predynastic Hierakonpolis) sites. This is combined with observations on the age and sex distribution and the proportion of hamadryas and anubis baboons to draw conclusions about the conditions of keeping, possible breeding on-site, provenance of the animals and the trade routes used for import. As in Tuna el-Gebel and Saqqara, the baboons from Gabbanat el-Qurud suffered from numerous metabolic diseases due to chronic lack of sunlight and an unbalanced diet. This and the demographic data suggest that there was a local breeding population derived from animals captured downstream from the Sudanese Nile Valley (for anubis) and from the Horn of Africa or the southern part of the Arabian Peninsula (for hamadryas). A new series of radiocarbon dates is provided, placing the baboons from Gabbanat el-Qurud between the end of the Third Intermediate Period and the beginning of the Late Period.

Plate tectonics in the twenty-first century

Plate tectonics was originally established as a kinematic theory of global tectonics, in which the Earth’s rigid outer layer, the lithosphere, consists of different size plates that move relative to each other along divergent, convergent or transform boundaries overlying the ductile asthenosphere. It comprises three elements: rigid lithosphere plates, ductile asthenosphere, and coupled movement systems. It operates through the interlinked processes of continental drift, seafloor spreading and lithospheric subduction, resulting in the generation, modification and demise of lithospheres throughout geological time. The system of lithospheric plates in horizontal and vertical movements forms the spatiotemporal linkages of matter and energy between the surface and interior of Earth, advancing the kinematic theory with a dynamic explanation. While top-down tectonics through lithospheric subduction plays a key role in the operation of plate tectonics, it is balanced for the conservation of both mass and momentum on the spherical Earth by bottom-up tectonics through asthenospheric upwelling to yield seafloor spreading after continental breakup. The gravity-driven subduction of cool lithosphere proceeds through convergence between two plates on one side, and rollback of the subducting slab makes the vacancy for upwelling of the hotter asthenosphere to form active rifting in backarc sites. Plate convergence is coupled with plate divergence between two plates along mid-ocean ridges on the other side, inducing passive rifting for seafloor spreading as a remote effect. Thus, plate tectonics is recognizable in rock records produced by tectonic processes along divergent and convergent plate margins. Although the asthenospheric upwelling along fossil suture zones may result in continental breakup, seafloor spreading is only induced by gravitational pull of the subducting oceanic slab on the remote side. Therefore, the onset and operation of plate tectonics are associated with a series of plate divergent-convergent coupling systems, and they are critically dependent on whether both construction and destruction of plates would have achieved and maintained the conservation of both mass and momentum on the spherical Earth. Plate margins experience different types of deformation, metamorphism and magmatism during their divergence, convergence or strike-slip, leaving various geological records in the interior of continental plates. After plate convergence, the thickened lithosphere along fossil suture zones in intracontinental regions may be thinned by foundering. This causes the asthenospheric upwelling to reactivate the thinned lithosphere, resulting in superimposition and modification of the geological record at previous plate margins. The operation of plate tectonics, likely since the Eoarchean, has led to heat loss at plate margins and secular cooling of the mantle, resulting in the decrease of geothermal gradients and the increase of rheological strength at convergent plate margins. Modern plate tectonics is characterized by the predominance of rigid plate margins for cold subduction, and it has prevailed through the Phanerozoic. In contrast, ancient plate tectonics, that prevailed in the Archean and Proterozoic, is dominated by relatively ductile plate margins for collisional thickening at forearc depths and then warm subduction to subarc depths. In either period, the plate divergence after lithospheric breakup must be coupled with the plate convergence in both time and space, otherwise it is impossible for the operation of plate tectonics. In this context, the creation and maintenance of plate divergent-convergent coupling systems are responsible for the onset and operation of plate tectonics, respectively. Although a global network of mobile belts is common between major plates on modern Earth, it is difficult to find its geological record on early Earth if microplates would prevail at that time. In either case, it is important to identify different types of the geological record on Earth in order to discriminate between the different styles of plate tectonics in different periods of geological history.

RESEARCH ON THE ABILITY OF YARNS FOR TEXTILE PROCESSING

The article is intended to study the destruction mechanism of yarns of different structures under different types of deformations that occur during their textile processing (weaving, knitting, etc.). Improving the wear resistance of yarns is one of the main ways to determine the causes of their destruction in textile processing with their subsequent elimination. The significance of this problem is determined by the fact that increasing the reliability and endurance of yarns is equivalent to increasing output without additional labor and material resources. The ability of yarns for textile processing is mainly determined by their mechanical characteristics in tension: tensile strength and elongation, endurance, longevity, cyclic elongation, and the like. In the regulatory documents, this ability is mainly assessed only by the indicators of tensile strength and elongation, which does not fully characterize their behavior in textile processing. Therefore, the study of the features of the yarn destruction under different types of mechanical interactions, as well as the impact of their structure on the process of destruction, is relevant for predicting their endurance and developing a new range of textile fabrics.

Experimental and numerical investigation on the cross-sectional mechanical behavior of prefabricated multi-cabin RC utility tunnels

Prefabricated multi-cabin utility tunnels have been increasingly adopted in modern city underground lifeline structures to accommodate the soaring demands for a variety of lifeline pipelines and to avoid congestion. According to the reconnaissance reports of past major earthquakes, these tunnels are vulnerable to three different types of deformations during earthquake action: axial compression and tension, longitudinal bending, and racking/ovaling. Compared with first two types of deformations, the cross-sectional mechanical performance of multi-cabin utility tunnels under the racking deformation has rarely been studied. To bridge this knowledge gap, quasi-static experimental and numerical studies were conducted in this paper to investigate the cross-sectional mechanical behavior of prefabricated multi-cabin utility tunnels for lifeline pipelines under the free-field racking deformation. The experiment was conducted at both the component joint and global levels. To be specific, a ½-scale L-joint and T-joint specimen, and a ¼-scale global specimen of a prefabricated multi-cabin utility tunnel section were designed. All specimens were tested under a combination of a constant axial load and cyclic lateral loads to impose the racking deformation to the cross-section of tunnel. The test results indicated that under the racking deformation, the L-joint was more vulnerable than the T-joint and the cross-sectional performance of the prefabricated multi-cabin utility tunnels would be dominated by the exterior walls. It is likely that the prefabricated multi-cabin utility tunnels will retain integrity under the free-field racking deformation of ground while suffer local failure to the exterior walls under the free-racking deformation. The test results were then employed to validate the numerical models. Moreover, good agreement was obtained between the numerical and experimental results, giving confidence in current numerical modeling techniques for prefabricated multi-cabin utility tunnels.

Multi-parameter optical gauge based on mode coupling effect in asymmetric index multi-core fibres

An optical gauge based on coupled multi-core fiber is proposed and experimentally demonstrated. By using direct laser writing to selectively break the fiber index profile symmetry, asymmetric mode coupling between cores is introduced. This allows to fabricate optical gauges with the ability to detect and differentiate different types of deformation in structures using just a single sensor.The fabricated optical gauges are compared with calibrated commercial gauges and fiber Bragg gratings as strain, vibration and curvature gauge. The tests indicate superior performance of this novel optical gauge over the commercially available sensors and offer the highest sensitivities. The proposed technology could be key to the fabrication of new fiber-based sensing devices with more capabilities and better features than previously achieved.

Finite Cross-Section Method for Mode Shape Recognition of Highly Coupled Beam-Type Structures

Abstract The mode shapes of beam-type structures, such as aircraft wings and wind turbine blades, involve a high degree of coupling between bending and torsional deformations. In the case of wind turbine blades, different types of deformation are typically easily recognized by visual observation. However, this visual approach is sometimes challenging for high-order mode shapes, which involve complex coupling of both bending and torsional deformations. This work proposes a novel mode shape recognition algorithm, called the finite cross-section method (FCSM), for application to highly coupled beam-type structures not only to identify the deformation components of complex beam mode shapes but also more importantly to quantify their respective relative contribution. In the application case study for the FCSM, the entire structure is discretized into multiple cross sections. The flap-wise, edge-wise, and torsional deformation components of the entire structure are determined at the cross-section level. The deformation components of the entire structure and their respective contribution are obtained from assembling all cross sections. To validate the mode shape recognition performance, FCSM is applied to and demonstrated on four test cases: (1) numerical mode shapes of a simple cantilever beam, (2) numerical mode shapes from a straight wind turbine blade, (3) numerical mode shapes of a swept wind turbine blade, and (4) experimental mode shapes from a high spatial resolution 3D scanning laser Doppler vibrometer (SLDV) modal test. Both numerical and experimental studies demonstrate that FCSM can successfully recognize the quantitative contribution of flap-wise, edge-wise, and torsional deformation.

Sagittal reduction genioplasty: Technical note

Without a doubt, the chin plays an important role on facial harmony. Both position and shape of the chin can significantly affect the facial profile. Genioplasty is a relatively simple surgical procedure that allows to correct deformities associated to the chin area. Several techniques and modifications have been described in the literature for different types of deformities. Anterior posterior reduction osteotomies of the chin have an unpredictable effect on the soft tissues and the use of the conventional sliding osteotomy have shown unsatisfactory cosmetic outcomes, this associated with step deformity, notching at the inferior border of the mandible among others. We propose a simple and effective technique that allows the correction of a chin deformity in cases where sagittal or vertical reduction is required with excellent esthetic results. Four case examples are presented for technique illustration.

Reassessing Depositional Conditions of the Pre-Apulian Zone Based on Synsedimentary Deformation Structures during Upper Paleocene to Lower Miocene Carbonate Sedimentation, from Paxoi and Anti-Paxoi Islands, Northwestern End of Greece

The studied area is situated in northwestern Greece and corresponds to the northern end of the Pre-Apulian Zone, in contact with the Apulian platform to the west and the Ionian Basin to the east. The proposed model is based on fieldwork, measured deformation structures, and age determination of the studied deposits. Until now, the known Pre-Apulian platform or Pre-Apulian zone represents the margins of the Apulian platform to the Ionian Basin and was formed due to the normal faults’ activity during the Mesozoic to Cenozoic Eras. Soft sediment deformation (SSD) structures are widespread within the upper Paleocene to lower Miocene limestones/marly limestones that are exposed in both Paxoi and Anti-Paxoi Islands, mostly along their eastern coasts, across sections of 2–3 km long and up to 60 m high. SSD structures, with a vertical thickness up to 10 m, have been observed in limestones and were formed during or immediately after deposition, during the first stage of sediment consolidation. SSD structures are cross-cut by normal faults, indicating their development during the rift stage. There are at least five different SSD horizons, and most of them present either an eastward or a westward progradation. These SSD structures are classified into four (4) different types of deformations: (1) thick synclines and anticlines, formed due to strong synsedimentary deformation; (2) strong and thick SSD structures that produced erosional contacts both with the underlying and the overlying undeformed horizons; (3) thin slumps, having sharp contacts with the underlying undeformed horizons and erosional contacts with the overlying undeformed horizons; and (4) thin slump horizons passing laterally to undeformed deposits in the same horizon. The studied SSD structures and their age of development introduce active margins between the Apulian platform and the Ionian Basin that have been influenced by normal fault activity. These normal faults have been active since the Ionian Basin changed gradually to a foreland basin, and after the tectonic regime changed from extension to compression, during the early to middle Eocene. It seems that compression in the studied Apulian platform margins arrived later and after the lower Miocene, and after the development of the SSD structures. The confinement of the lower Miocene deposits, both northwards and southwards (in Anti-Paxoi Island), indicates the presence of active transfer faults, with flower structure geometry, that were formed during sedimentation, producing highs and troughs. The present open anticline geometry of Paxoi Island indicates that the Island represents the forebulge area of the middle Miocene Ionian Foreland due to Ionian Thrust activity.

Influences of Salinity on Embryonic and Larval Development of Striped Catfish Pangasianodon hypophthalmus

Salinity intrusion in coastal areas due to climate change is alarming. In this study, the effects of salinity on embryonic and larval development of striped catfish (Pangasianodon hypophthalmus) were studied experimentally. Embryos and larvae were exposed to seven salinity treatments (0, 2, 4, 6, 8, 10, and 12 ppt), each with three replications. Considerable survivability of embryos was recorded up to 6 ppt salinity. Mortality of embryos significantly increased at 8 and 10 ppt salinity, and 100% mortality was displayed within 12 h of exposure at 12 ppt salinity. The rate of hatching was significantly reduced at 8 and 10 ppt salinity. The 24 h lethal concentration (LC50) value of salinity for embryo was 11.24 ppt. Different types of deformities, such as undeveloped yolk sac, elongated gastrula yolk sac, and yolk sac bud, were highest at 10 ppt salinity. Similar to the embryo, considerable survivability of larvae was recorded up to 6 ppt salinity, and 100% mortalities were found within 24 h of exposure at 12 ppt salinity. The 24 and 48 h LC50 values of salinity for larvae were 10.63 and 8.48 ppt, respectively. Several types of deformities, including yolk sac ulceration, spine scoliosis, tail bent, yolk sac edema, and compromised swim bladder inflation, were highest at 10 ppt salinity after 48 h of exposure. Within 24 h of exposure, about 80% yolk sac of the larvae was absorbed at 8 and 10 ppt salinity, while 30%–50% yolk sac was absorbed at 0–6 ppt salinity. Growth rates in terms of length and weight were higher at 0, 2, and 4 ppt salinity and moderate at 6 and 8 ppt salinity. Overall, the current findings define the limits to optimize hatchery procedures for the culture of this species in low saline brackish water.

A highly sensitive stretchable strain sensor based on multi-functionalized fabric for respiration monitoring and identification

Wearable strain sensors have generated considerable recent research interest due to their huge potential in the real-time detection of human body deformation. State-of-the-art strain sensors are normally fabricated through conductive networks with a single sensing element, which always faces the challenge of either limited stretchability or inferior quality in sensitivity. In this work, we report a highly sensitive strain sensor based on a multi-functionalized fabric through carbonization and polymer-assisted copper deposition. The sensor shows high sensitivity (Gauge factor ∼ 3557.6 in the strain range from 0 to 48%), and outstanding stretchability up to the strain of 300%, which is capable of detecting different types of deformation of the human body. By integrating the high-performance sensor with a deep learning network, we demonstrate a high-accuracy respiration monitoring and emergency alarm system, showing the enormous application potential of the sensor in personal and public healthcare.

Radial alignment of carbon nanotubes for directional sensing application

Multidimensional force-sensing stretchable electronic skins made of nanomaterials with low-dimensional morphologies are of great importance in the fields of robotics, rehabilitation, and prosthetics. Herein, we report a carbon nanotube (CNT) based strain sensor with a unique alignment to detect multidirectional strains. Radially aligned CNTs sealed between polydimethylsiloxane layers exhibit a gauge factor (GF) that is comparatively better than that of a conventional CNT-based sensor. The optimum concentration of radially aligned CNTs limits the conduction path of electrons which, in turn, improves the sensitivity of the sensor. To tune the GF further, a tape-peeling method is used which not only increases the GF of the device but also improves its transparency. When attached to the human skin, the sensor can differentiate between different types of deformation. The sensor can also be employed in multichannel, interactive electronic robotics systems. It can also has potential for application as a wearable detector for human motion such as bionic ligaments in soft robotics.

KNN based piezo-triboelectric lead-free hybrid energy films

In recent times, the triboelectric and piezoelectric effects have garnered significant attention towards developing advanced material composites for energy harvesting and sensory applications. In this work, potassium sodium niobate (KNN) based energy films (EF) have been developed to utilize mechanical energy while simultaneously taking advantage of triboelectric and piezoelectric mechanisms. The KNN particles were synthesized using a wet ball milling technique and then incorporated into a polyvinylidene difluoride (PVDF) matrix together with addition of multi wall carbon nanotubes (MWCNT). The film was used to develop a piezoelectric nanogenerator (PENG) fitted with copper electrodes. The piezoelectric output of the film was further tested utilizing copper electrodes, at variable tapping frequency (60 BPM to 240 BPM) and pressure (10–40 psig) were used when activating the pneumatic piston. The open circuit voltage increased with the increase of both tapping frequency and pressure. The maximum piezoelectric output voltage was observed to be 35.3 V while the maximum current was noted as 15.8 µA. The films also showed unique output signals for different types of deformations performed under hand pressure. The film was further utilized to build a piezo-triboelectric hybrid nanogenerator to check its hybrid performance. The maximum output was observed to be 54.1 V and 29.4 µA. This film was integrated with conventional electronic components (bridge rectifiers, resistors, and capacitors) and tested for its ability to harvest energy. The hybrid nanogenerator can charge a 0.1 µF capacitor to 9.4 V in 60 s. The optimum output power for the device was measured to be 0.164 W. The film was further attached with a Kapton film and showed a hybrid output of 113.2 V. This experiment endorsed the potential of the KNN based energy films for multifunctional applications like force, pressure, and motion sensing as well as lead free energy harvesting. Potassium sodium niobate (KNN) was synthesized and incorporated into PVDF along with MWCNT to produce lead-free piezoelectric and piezo-triboelectric hybrid energy films. The high piezoelectric and piezo-tribo hybrid output response showed its potential in biomechanical energy harvesting. Besides, the energy film can be utilized for biomechanical motion and pressure sensing operations. • KNN/PVDF/MWCNT based lead-free energy film was synthesized for piezoelectric and triboelectric operation. • The energy film was tested at variable pressure, load frequency, and finger motions. • The hybrid energy film showed high output of 54.1 V and 29.4 μA. • The energy film can be used for powering small electronic devices and multidimensional sensory operations.

Why and How Does the Actual Spectral Response Matter for Microwave Radiance Assimilation?

AbstractBased on Global/Regional Assimilation and PrEdiction System‐Global Forecast System and actual Spectral Response Functions (SRFs) of three Selected Single‐Passband Channels (Channels 5–7) of FengYun‐3D MicroWave Temperature Sounders‐2, impacts of actual SRFs on Brightness Temperature (TB) simulation were analyzed. Compared with simulation by ideal SRFs, averaged STandard DeViation and bias of Observation minus Background by actual SRFs decrease about −5.0% and 37.3%. The reductions on Equatorial regions are more obvious than middle and high latitudes. Five types of deformations were put forward to analyze their impacts on TB simulation. Attenuation, shifting, and extending of passband have more impacts on simulated TB compared with trap on passband. The differences between TBs simulated using ideal and actual SRFs do not depend on the magnitude of the difference between ideal and actual SRFs, but on the balances of different types of deformations of actual SRF.