Simple Solution Research Articles

On semi-orthogonal matrices with row vectors of equal lengths

When does a rectangular matrix with an orthonormal set of column vectors have row vectors of equal lengths? The column spaces of such matrices are multidimensional generalizations of the projection plane used in isometric perspective. We show that in the absence of unexpected linear relations, any rectangular matrix can be row-scaled so that if we were to orthonormalize the column vectors, the row vectors would attain equal lengths in the process. We use Grassmann coordinates to reduce the question into an instance of the famous matrix scaling problem, and with the help of existing theory introduce simple numerical solutions.

Simple and cost effective solution to applying cold sensation in the assessment of regional anaesthesia

Simple and cost effective solution to applying cold sensation in the assessment of regional anaesthesia

Analytical considerations of the load‐deflection behavior in fibers during a filament winding process

AbstractFilament winding is a manufacturing process used in the construction of fiber composite structures, where a thermoset resin impregnated bunch of fibers is deposited on a rotating mandrel. The evolving stress and strain states due to thermal and mechanical loads during the manufacturing process are of particular interest to avoid subsequent failure of the parts. In this first approach, the mechanical load within the fiber, mainly driven by the pre‐stressed fiber tension, is investigated. Thus, the development of the fiber tension and the pressure on the mandrel as a function of the number of windings is examined. Therefore, models based on the theory of large and small deformations are derived under certain assumptions, resulting in a boundary value problem. In case of large deformations, the boundary value problem using a three‐dimensional formulation based on incompressible, isotropic hyperelasticity does not yield a simple solution. Using a small deformation formulation on the basis of a one‐dimensional consideration an analytical solution can be found. The problems are described in curvilinear coordinates. From the derived models, the required quantities including the fiber tension, the pressure on the mandrel, also as a function of the number of windings, and the fiber elongation can be calculated.

Supporting Aging in Place with the Introduction of Artificial Intelligence Technologies

As our growing population ages, there is a stronger push to age in place. Adults want to stay in their homes and communities as long as possible despite degenerative health issues. With adequate education and support, the growing desire for adults to age in their homes can be met with the strategic integration of AI technologies to maximize safety and bolster engagement in meaningful activities. This seemingly simple solution is complicated by the intersection of unique learning styles and the complexities that come with a generation that is cautious of even the simplest technology. Adopting a person-centered framework is vital for the success of AI-supported aging in place. As an occupational therapist, with experience across geriatric populations and a special interest in adaptive technology, I provide unique insight into effectively introducing AI technologies into the daily lives of older adults throughout this experiential report.

Analysis on future development of solar cells focusing on materials and devices

In recent times, solar cells have garnered significant attention due to their numerous advantages. These include continuously improving energy conversion efficiency, a simple solution preparation method, flexibility, lightweight design, wearability, suitability for ultra-lightweight space applications, and low-cost material components. Perovskite solar cells have achieved impressive efficiencies of over 25% by using high-quality perovskite films synthesized at low temperatures and by making advancements in compatible interface and electrode materials. Moreover, the stability of cells has become a major focus of research. This paper analyzes the development history, material system, device structure, challenges, and future development direction of perovskite solar cells. The unique photoelectric properties and tunable band gap of materials have made them a hot topic in the field of solar cells. In this paper, the basic characteristics and synthesis methods of perovskite materials are introduced before discussing the device structure, interface engineering, and stability of perovskite solar cells in detail. Finally, it prospects on the future development trend of perovskite solar cells.

The 3rd Hutchinson lecture: numerical modelling of forests with uprooting as a nature-based solution to mitigate flow-type landslides

AbstractTo protect human lives and infrastructure in mountainous regions from flow-type landslides, engineered countermeasures, such as rigid and flexible barriers, are installed along predicted flow paths. Over recent years, research efforts in physical and numerical modelling have helped advance the understanding of impact mechanisms involved and enabled the optimization of the design of engineered solutions. With the advent of sustainable engineering, attention has shifted towards the use and development of nature-based solutions to impede flow-type landslides. A simple nature-based solution is to consider the effects of forests on the mobility of flow-type landslides. However, to leverage forests, the complex flow-stem interactions and effects of uprooting need to be captured. In this paper, details and results of a new GPU-empowered MPM-LSDEM numerical solver that simulates the effects of flows through tree stems that can uproot are presented along with systematic evaluation of the solver. Simulations of flow-forest interaction with and without uprooting show that forests have profound effects on flow forest interaction. For dense forests, uprooted stems can push flow material to enhance its runout distance. Additionally, uprooted stems tend to concentrate near the front of the flows even if they were evenly distributed throughout the model forest at the beginning. The impact force exerted by a stem can be considered concentrated loading and can damage barriers along the flow path. Taken together, hazard assessment tools that can model the effects of uprooting are crucial to close predictions of hazard extent (i.e., runout distance) and the design of physical countermeasures such as barriers.

Wavelength Stabilization of Entangled Biphotons Using Dynamic Temperature Compensation for Quantum Interference Applications

AbstractIn this paper, a dynamic temperature compensation method is presented to stabilize the wavelength of the entangled biphoton source, which is generated on spontaneous parametric down‐conversion from a magnesium oxide doped periodically poled lithium niobate waveguide. Utilizing the dispersive Fourier transformation technique, the photon wavelength variation is monitored in case of conventional static temperature control, revealing a long‐term wavelength drift up to 556.8 pm over a 14‐h measurement period. A Hong‐Ou‐Mandel (HOM) interferometer is constructed to assess the impact on quantum applications, showing a decrease in visibility from 95.5% to 69.4%. To address this issue, a digital proportional‐integral‐differential algorithm is implemented to dynamically compensate the working temperature variation of the waveguide, thereby instantly stabilizing the wavelength to a peak‐to‐peak fluctuation of +138.05 pm/‐127.61 pm with the standard deviation being 30.49 pm. The wavelength stability shows more than a hundredfold enhancement in terms of Allan deviation, reaching at an averaging time of 10000 s. With the dynamic control in operation, the HOM interference visibility turns to stable at 96.1% ± 0.6%. The method provides a simple and accessible solution for precisely controlling and stabilizing the wavelength of entangled biphotons, thus improving performance in various quantum information processing applications.

Stable Organic‐Inorganic Hybrid Sb(III) Halide Scintillator for Nonplanar Ultra‐Flexible X‐Ray Imaging

AbstractFlexible scintillator screens with excellent stability and low detection limits are crucial for X‐ray imaging applications. 0D organic metal halide materials have emerged as a strong contender in the scintillator fields, owing to their excellent optical characteristics and simple maneuverability. Herein, high‐quality and large quantities of C38H36P2Sb2Cl8 single crystals are synthesized through a simple solution approach. The prepared single crystals with dimer‐structure [Sb2Cl8]2− exhibit yellow emission with a near‐unity high photoluminescence quantum yield (PLQY) of 99.8%, and possess an exceptional light yield of 41300 photons MeV−1, and a detection limit as low as 45.6 nGyair s−1. On this basis, a large‐size and ultra‐flexible C38H36P2Sb2Cl8 scintillator utilized for X‐ray imaging is prepared by template assembled method, demonstrating a high spatial resolution of 8.15 lp mm−1. The prepared ultra‐flexible scintillator screen can achieve excellent X‐ray imaging even after multiple bending and stretching, which can also provide clear non‐planar X‐ray imaging for irregular objects. In addition, the scintillator shows excellent stability in light, heat, X‐ray irradiation, and water. These results not only expand the optoelectronic application field of organic‐inorganic hybrid antimony halides but also promote the rapid development of efficient ultra‐flexible scintillators.

Bilayer Boost to UV Assisted Supercapacitors: Enhanced Performance with Transparent TiO2/MoO3 Heterojunction Electrode

Photo‐assisted supercapacitor is a promising smart device component for achieving both energy conversion and storage. The photo‐assisted functionality in a supercapacitor is realized through the choice of photo responsive electrode material under suitable illumination conditions. The well‐known electrochemically active electrode materials are wide band gap semiconductors which absorb strongly in UV light. However, most of the prior studies on photo‐assisted supercapacitors used visible light. Herein, we present a transparent TiO2/MoO3 bi‐layer heterojunction made by simple solution process as an efficient electrode for photo‐assisted supercapacitors under UV light illumination. The electrochemical performance of the electrode is significantly enhanced even with a less intense (0.05mW/cm2) UV light, compared to dark as well as the single layer electrode under same illumination condition. The highest areal capacitance of 63.25 mF/cm2 at 0.1 mA/cm2 is achieved, that surpasses most of the recent relevant reports. The synergetic effect of UV illumination and the built‐in potential at the type II heterojunction interface encourages ion insertion and better collection of the photo‐generated carriers. The unique bi‐layer design also leads to better rate capability features. Thus, the work presents a new prospect for the development of transparent energy storage devices to be used in future smart technologies.

Green synthesis of N-doped-carbon dots/ZnO for enhanced photocatalytic degradation of methylene blue dye: optimization of reaction parameters.

In this research work, nitrogen-doped carbon dots (N-CDs) adorned zinc oxide nanoparticles (N-CDs/ZnO) were successfully synthesized by a simple and cost-effective solution dispersion method and later on used as photocatalyst for decontamination of aqueous methylene blue (MB) dye on irradiation of UV light (300 W, 320-400nm) at room temperature. Both the N-CDs and ZnO were prepared through green technique utilizing non-toxic, inexpensive and eco-friendly precursors, namely Foeniculum vulgare and Psidium guajava leaf extract, respectively. All the synthesized samples exhibited crystalline nature with average diameter of particle 4.42nm, 12.38nm and 14.11nm corresponding to N-CDs, ZnO and N-CDs/ZnO, respectively. Further, band gap energy value (Eg) of 3.43, 2.76 and 2.49eV for N-CDs, ZnO and N-CDs/ZnO, respectively, were obtained by using Tauc's plot. The photocatalytic capability of the sample N-CDs/ZnO was compared with bare ZnO nanoparticles, utilizing identical experimental conditions. The results demonstrated that the composite exhibited notably higher photocatalytic degradation efficiency than bare ZnO nanoparticles up to 15.54%. Lower band gap value of N-CDs/ZnO was the major factor for exhibiting this behaviour, decreasing the recombination rate and thus enhancing the efficiency. Furthermore, N-CDs/ZnO exhibited 98.17% MB degradation under optimized conditions (0.03g, 5ppm, pH 10). The resultant N-CDs/ZnO exhibited good stability and decontamination efficiency up to five cycles with efficiency loss of only 7.89%. Along with, trapping experiments was conducted to analyze the role of active species involved for deep understanding of mechanism. The order of efficiency of active constituents was observed to be: •O2- > h+ > •OH. The study analyzed the non-toxic nature of treated water, revealing normal plant growth, suggesting its potential use in irrigation of parks and roadside areas. Overall, present research work obeys the green chemistry principles with the fabrication of highly efficient, eco-friendly, cost-effective photocatalyst N-CDs/ZnO by utilizing the green precursors for the whole research work.

Detection of HBV pgRNA by catalytic hairpin assembly combined with two Kinds of immunochromatographic strips

Serum HBV pregenomic RNA (pgRNA), as an important marker of HBV replication activity, has significant potential in virological monitoring and efficacy evaluation. In this study, two highly sensitive HBV pgRNA detection platforms were developed based on catalytic hairpin assembly technology, combined with flow lateral immunochromatography and colloidal gold immunochromatography. The signal amplification achieved by CHA technology avoids the dependence of RT-qPCR on thermal cycling equipment. The experimental results showed that the minimum detection limit of CHA-LFIA was 1 pM, and the minimum detection limit of CHA-GICA was 10 pM. Both CHA-LFIA and CHA-GICA had good specificity and could effectively distinguish between target RNA and non-target sequences. The results of CHA-LFIA and CHA-GICA were highly consistent with those of RT-qPCR, and had the potential for clinical application. This study provides a simple, rapid and innovative solution for the detection of HBV pgRNA, which does not rely on expensive equipment, and can be used for the early diagnosis and treatment monitoring of HBV infection.

Calibration and implementation of a design tool for drag anchors in clay

Abstract Drag anchors are considered as one of the most applicable anchor solutions for floating offshore wind as they can be used for a wide range of soil conditions. For feasibility studies of floating offshore wind farms different anchor concepts needs to be compared in order to select the most proper anchor solution. To do so, the level of details in the analysis for the various anchor types must be similar. Currently design charts are adopted as a simple design method for drag anchors. However, design charts are developed for specific soil conditions, and do not account for site specific soil conditions. To have similar precision, as analytical solutions for suction anchors, a simple design methodology that can account for site specific soil conditions for drag anchors must be adopted. This paper presents an example for how a simple analytical solution can be calibrated against design charts, which makes it possible to account for site specific soil conditions, resulting in a better basis for comparing early stage drag anchor design to other anchor solutions.

Multi-layered quasi-2D perovskite based triboelectric nanogenerator

Inorganic-organic perovskites are considered as one of the emerging candidates as a tribopositive material in triboelectric nanogenerators (TENG) owing to their unique functionalities. Among them, quasi-two-dimensional (quasi-2D) perovskites are promising materials for TENG due to layered nature, excellent environmental and chemical stability, tunability, and excellent electrical properties. Herein, we investigate the performance of TENG based on multiple series of perovskite layers using simple solution processing technique. The dimensionality of the perovskite layers is attained by changing the stoichiometric ratios of phenylethylammonium iodide (PEAI), lead iodide (PbI2), methylammonium iodide (MAI). The quasi-2D based TENG generates the maximum output electrical performance with a voltage of 306V, current of 4.71µA, and maximum power density of 3.48µW/cm2 at the optimum value of (<n> = 5) due to the higher concentration of C–N and N–H groups. Moreover, the fabricated device shows stable performance for 12000 cycles. The TENG device is further utilized to charge the various commercially available capacitors, for lightning of light-emitting diodes (LEDs), and to power up low-power electronic devices. These results demonstrate the effect of the dimensionality of perovskites on the output performance of the TENG for use in next-generation energy harnessing.

Sustainable synthesis of PVA@ZnO:Ga3+ nanocomposite films for UV shielding, food preservation, shape memory and anti-counterfeiting applications

Herein, we successfully fabricated transparent and highly flexible polyvinyl alcohol@ZnO:Ga3+ (PVA@ZnO:Ga3+) nanocomposites (NCs) films by simple solution casting method. Upon excitation at 266 nm, both the ZnO:Ga3+ nanoparticles (NPs) and the PVA@ZnO:Ga3+ NCs exhibit a prominent peak at 385 nm and a broad peak around 550 nm. The optimized PVA@ZnO:Ga3+ NCs demonstrated the most effective ultra violet (UV) blockage across the UV-A (99.99 %), UV-B (100 %) and UV-C (100 %) and high energy blue light HEBL (94.63 %). However, PVA alone absorbed <25 % of the light in all UV regions. Packaging of fresh cherry fruit with PVA@ZnO:Ga3+ (0.1 wt%) NCs enhanced the shelf-life up-to 15 days of storage under room temperature. These innovative NCs packaging films could provide a green, environment-friendly and antimicrobial system to combat the shorter shelf life of cherry fruit. The optimized NCs exhibited excellent shape recovery under pH conditions of 1, 7 and 13 and at a temperature of 70 °C, returning to its original shape within 120, 150, 160 and 6 sec, respectively. This emphasizes the NCs remarkable water-induced shape memory ability. Further, PVA@ZnO:Ga3+ NCs security ink offers strong anti-counterfeiting (AC) properties with UV luminescence and stability against UV exposure, aging and temperature effect. It adheres well to various substrates, ensuring long-term durability and resistance to replication. Overall, the results clearly show that ZnO:Ga3+ NPs hold great promise for applications in AC technology, UV blocking and the food packaging industry, thanks to their low cost, biocompatibility, flexibility and transparency.

A libraries reproducibility hackathon: connecting students to University research and testing the longevity of published code

Reproducibility is a basis of scientific integrity, yet it remains a significant challenge across disciplines in computational science. This reproducibility crisis is now being met with an Open Science movement, which has risen to prominence within the scientific community and academic libraries especially. To address the need for reproducible computational research and promote Open Science within the community, members of the Open Science and Data Collaborations Program at Carnegie Mellon University Libraries organized a single-day hackathon centered around reproducibility. Partnering with a faculty researcher in English and Digital Humanities, this event allowed several students an opportunity to interact with real research outputs, test the reproducibility of data analyses with code, and offer feedback for improvements. With Python code and data shared by the researcher in an open repository, we revealed that students could successfully reproduce most of the data visualizations, but they required completing some manual setup and modifications to address depreciated libraries to successfully rerun the code. During the event, we also investigated the option of using ChatGPT to debug and troubleshoot rerunning this code. By interacting with a ChatGPT API in the code, we found and addressed the same roadblocks and successfully reproduced the same figures as the participating students. Assessing a second option, we also collaborated with the researcher to publish a compute capsule in Code Ocean. This option presented an alternative to manual setup and modifications, an accessible option for more limited devices like tablets, and a simple solution for outside researchers to modify or build on existing research code.

Triboelectric Nanogenerator Based on Tin Doped Zinc Oxide and Polyvinyl Alcohol Composite Thin Film for Energy Harvesting Applications

The triboelectric nanogenerator (TENG) collects mechanical energy from its surroundings and converts it to electrical signals that can be used in sustainable energy harvesting technologies to help maintain the social ecosystem. However, TENG operation with pure triboelectric material may not be sufficient to power a small electronic system without modification. The optimal material capable of producing significant electrical energy with flexible structures remains a major barrier to practical application. In this study, tin-doped zinc oxide (Sn:ZnO) and polyvinyl alcohol (PVA) composite thin films were prepared using a simple solution immersion technique at various Sn atomic percentage (at.%) concentrations for use in TENG devices. The crystalline quality of a composite thin film made of Sn:ZnO and PVA was identified using x-ray diffraction. The microstructure changes of the composite thin film were found to be influenced by Sn doping, as studied using optical microscopy. The TENG with 2.5 at.% Sn:ZnO/PVA composite thin film and Kapton film achieved the highest peak voltage of 8.5 V in open circuit and 90 µW output power at 1 MΩ. The produced electrical output was then used to store energy in capacitors. According to its TENG properties, the Sn:ZnO/PVA composite thin film-based TENG has the potential to be used in low power electronic devices.

VLFATRollout: Fully transformer-based classifier for retinal OCT volumes

Background and Objective:Despite the promising capabilities of 3D transformer architectures in video analysis, their application to high-resolution 3D medical volumes encounters several challenges. One major limitation is the high number of 3D patches, which reduces the efficiency of the global self-attention mechanisms of transformers. Additionally, background information can distract vision transformers from focusing on crucial areas of the input image, thereby introducing noise into the final representation. Moreover, the variability in the number of slices per volume complicates the development of models capable of processing input volumes of any resolution while simple solutions like subsampling may risk losing essential diagnostic details. Methods:To address these challenges, we introduce an end-to-end transformer-based framework, variable length feature aggregator transformer rollout (VLFATRollout), to classify volumetric data. The proposed VLFATRollout enjoys several merits. First, the proposed VLFATRollout can effectively mine slice-level fore-background information with the help of transformer’s attention matrices. Second, randomization of volume-wise resolution (i.e. the number of slices) during training enhances the learning capacity of the learnable positional embedding (PE) assigned to each volume slice. This technique allows the PEs to generalize across neighboring slices, facilitating the handling of high-resolution volumes at the test time. Results:VLFATRollout was thoroughly tested on the retinal optical coherence tomography (OCT) volume classification task, demonstrating a notable average improvement of 5.47% in balanced accuracy over the leading convolutional models for a 5-class diagnostic task. These results emphasize the effectiveness of our framework in enhancing slice-level representation and its adaptability across different volume resolutions, paving the way for advanced transformer applications in medical image analysis. The code is available at https://github.com/marziehoghbaie/VLFATRollout/.

Bosonization and correlators of the one-dimensional Hubbard model

Abstract We present a simple derivation of the Luttinger liquid relation for the one-dimensional Hubbard model, considering a finite U and in the U = ∞ limit. We describe a simple solution of the Hubbard model in the infinite repulsion limit and use it to calculate the correlators of the model in this limit in a simple and physical way using the bosonization technique. We then calculate the asymptotics of the correlators of the model at arbitrary U through a single parameter, which can be calculated from the Bethe Ansatz solution. Our derivation of the critical exponents is simple and allows one to express different physical operators of the Hubbard model through the charge and spin Bose fields in a direct and physically transparent way.

A Flexible Organomagnetic Single-Layer Composite Film with Built-In Multistimuli Responsivity.

Materials possessing multiple properties and functionalities, that can be controlled or modulated by external stimuli, are a central focus of current research in materials sciences due to their potential to significantly enhance various future technological applications. Herein, we report a significant advancement in this field through the development of a smart, multifunctional organomagnetic composite material. By utilizing a thin layer of polydimethylsiloxane (PDMS) and polypyrrole (PPy) precursors, doped with nickel nanoparticles (NiNPs), we have created an innovative organomagnetic, PDMS/PPy/NiNPs (PPN), single-layer composite film that displays multistimuli responsivity. The study presents the first demonstration of a multifunctional flexible, three-component film structure integrating the structural and flexible PDMS component, together with a conductive polymer component and metal-based nanoparticles into a single-layer design, which displays enhanced and unprecedented responsivity properties against multiple different stimuli. Unlike typical stacked multilayered structures, that exhibit one or two functionalities at most, this novel configuration exhibits multiple functionalities, including magnetoresistance, mechanical stress response, piezoresistivity, and temperature change sensitivity. The as-prepared film demonstrates notable magnetoresistance responsivity, with a relative electrical resistance, ΔR/R0, changing under a weak magnetic field and under ambient conditions. The significance of our study lies in the film's versatility, stability, and sensitivity, especially within the physiological temperature range, making it highly relevant for future biomedical applications. Furthemore, the film's sensitivity to mechanical deformation reveals an impressive piezoresistance behavior. Unlike existing multilayer architectures of higher complexity, our single-layer thin film offers a simpler, more flexible, and reliable solution with a broad range of stimuli-sensing capabilities. The significance of this novel multiresponsive composite material is underscored by the growing demand for advanced materials in biomedical devices, magnetic switches, sensors, electronic skin, transistors, and organic spintronic devices. These promising organomagnetic self-standing layers provide a robust platform for future technological innovations.

Simple solution and paper-based fluorescent aptasensors for toxic metal ions, thallium(l) and lead(ll).

Heavy metal ions, such as thallium(I) and lead(II) are environmental toxicants known to cause a severe threat to human and ecosystem health. This work investigates aptamers and intercalating chromophore-based complexes for the detection of these toxic species. In one method, a selective label-free "turn-on" biosensor was developed using a G-quadruplex-intercalating agent, berberine. Fluorescence, melting temperature (Tm), and circular dichroism analysis confirmed the affinity and selectivity results, illustrating the potential of these aptasensor methods for improving detection limits. These fluorescence assays were found to perform with a detection limit of 3.4 μM for Tl(I) and 0.84 nM for Pb(II). Furthermore, the assays were challenged successfully with Tl(I) and Pb(II) spiked into river water samples. We next developed paper-based fluorescent assays for Tl(I) and Pb(II), where the aptamer/berberine complex was spotted onto the paper test zone. When Tl(I) or Pb(II) ions solutions were spotted onto the top of the test zone and the spot was illuminated with a portable UV light (365 nm), a strong green fluorescence could be easily visualized with the naked eye. The lowest detection limits achieved with these fluorescent paper-based assays for Tl(I) and Pb(II) were 1.1 nM and 1.6 nM, respectively. The two fluorescent approaches presented here have the potential to be the basis of rapid, fast, and cost-efficient screening assays for these toxic species.