Compact Setup Research Articles

Single-pixel computational spectrometer based on nonlinear spectrum modulation

Computational spectroscopy with modulated light spectrum is especially well-suited for application scenarios where active illumination is needed. Most of the existing computational spectroscopy, however, uses ambient illumination and modulates the signal spectrum that is reflected or transmitted from objects, mainly because of the lack of a light source with effective spectrum modulation. Here, we present a novel computational spectrometer featuring light-source spectrum modulation achieved through polarization-induced nonlinear spectrum modulation, offering a compact and low-cost system apparatus. The modulated spectrum can evolve periodically by managing polarization-induced nonlinear phase as well as pump power, within the range from 1000 nm to 1100 nm. Combining wavelength multiplexing and compressed sensing, we can achieve a minimum spectral resolution of 0.2 nm, which is comparable to the commercial spectrometer. The utilized objects with sparse and non-sparse spectra are successfully reconstructed both in simulation and experiment, within an effective reconstruction spectral range from 1021 nm to 1077 nm.

Methane-filled hollow fiber: A cost-effective pathway to compress high repetition rate ytterbium femtosecond lasers using self-phase modulation

Abstract Hollow-core fiber (HCF) based temporal pulse compression is widely used to generate few-cycle pulses. Here, we demonstrate the strength of methane (CH4) as a nonlinear medium for HCF-based pulse compressors to achieve high average power few-cycle pulses of sub-16 fs duration with > 70% transmission and up to 250 kHz repetition rate in a compact setup and present it as a cost-effective alternative to highly expensive and scarcely available noble gases.

Spatially homogeneous spectral broadening of Yb lasers with field mapping beam shaping optics.

Yb:YAG thin disk lasers can deliver high average power, high-energy pulses of fundamental mode. To achieve spatially homogeneous spectral broadening of the pulses in a compact setup, we propose utilizing a thin-film compression (TFC) scheme following beam shaping via field mapping optics. In our proof-of-principle experiment, the pulse from a Yb:YAG laser was converted from a Gaussian beam to a nearly flat-top beam by a π-shaper. The spectral width of the pulse was broadened from 3.1 nm to 6.6 nm after accumulating nonlinear phase shift in a YAG crystal. This technique resulted in high spectral homogeneity and mitigated degradation of focusability typically observed after spectral broadening. We believe this approach offers a promising solution for the post-compression of high-energy Yb lasers within a compact setup.

Particle Vertical Mixing and Horizontal Conveyance Within an Ambient Temperature Fluidized Bed

Previous studies have shown the advantages of particle-to-sCO2 fluidized bed (FB) heat exchangers, which include high heat transfer coefficients, low material cost, and the ability to horizontally convey solid particles. This paper outlines the design and testing of a compact cold flow FB test apparatus to characterize horizontal conveyance through convolutions within a 100 kWth FB heat exchanger design. Horizontal conveyance is an advantage in FBs because it enables more compact designs for heat exchangers. Two mass flow rates, 0.5 & 1 kg/s, at the inlet & outlet of the FB. To determine consistency of the flow rates, Student’s t-tests were used to assess whether the inlet & outlet values were statistically similar. The mass flow rate exiting the bed was statistically similar to the flow rate entering the bed for both cases, but each case featured a wider range and standard deviation. The range and standard deviation of the 1 kg/s flow rate was 0.69-1.23 kg/s and 0.12 kg/s respectively, and the 0.5 kg/s test featured a range and standard deviation of 0.37-0.73 kg/s and 0.09 kg/s, respectively. These measurements provide confidence that large-scale designs can successfully horizontally convey particles at ````~1.5x minimum fluidization velocity (U­mf) without significant variation in flow rate. A method to characterize the degree of particle vertical mixing and bubble frequency within the FB is also introduced. By using a high-resolution camera together with particle velocimetry, particle motion in the X and Y directions can be estimated to assess bed mixing and bubble frequency.

Ultrasensitive Specific Detection of Anti-influenza A H1N1 Hemagglutinin Monoclonal Antibody Using Silicon Nanowire Field Effect Biosensors.

Rapid and sensitive detection of virus-related antigens and antibodies is crucial for controlling sudden seasonal epidemics and monitoring neutralizing antibody levels after vaccination. However, conventional detection methods still face challenges related to compatibility with rapid, highly sensitive, and compact detection apparatus. In this work, we developed a Si nanowire (SiNW)-based field-effect biosensor by precisely controlling the process conditions to achieve the required electrical properties via complementary metal-oxide-semiconductor (CMOS)-compatible nanofabrication processes. The SiNW surface was chemically modified with 2-aminoethylphosphonic acid, followed by a dehydration condensation reaction with influenza A H1N1 hemagglutinin (HA1), to enable specific detection of anti-HA1 immunoglobulin G (IgG). We successfully detected the anti-influenza IgG with concentrations ranging from 1 aM to 100 nM, achieving a remarkable detection limit of 6.0 aM. To demonstrate specificity, a control experiment was conducted using normal mouse IgG with concentrations of 6 aM to 600 nM. The results showed a high specificity, with the signal being 6-fold greater for the target IgG compared to the control IgG. This work demonstrates the capability of SiNW biosensors to detect anti-influenza A H1N1 hemagglutinin monoclonal antibody with enhanced detection sensitivity and specificity. This work lays the groundwork for future applications in detecting antibodies after vaccination or immunotherapy, contributing to the effective management of infectious pandemics.

Harnessing individual nitrogen-vacancy centers with a compact and portable confocal microscope

Abstract Recent advancements in quantum technology have highlighted the potential of nitrogen-vacancy (NV) centers in diamond. However, fully realizing this potential requires addressing challenges related to the size, complexity, and cost of current optical systems used for NV center manipulation. In this work, we present a compact and portable confocal setup specifically designed for the efficient detection and control of single NV centers. Our system facilitates optical initialization and readout of individual NV center photoluminescence signals, enabling coherent spin control and nanoscale-resolution magnetic field sensing.

Portable emissions toxicity system: Evaluating the toxicity of emissions or polluted air by exposure of cell cultures at air-liquid interface in a compact field-deployable setup.

Exposure of cell cultures at air-liquid interface (ALI), mimicking i.e. human lung surface, is believed to be one of the most realistic means to model toxicity of complex mixtures of pollutants on human health. The complexity of the close cooperation of "emissions source" and toxicology groups and of the instrumentation are among the limiting factors of ALI. In this work, the concepts of ALI exposure and real-world emissions monitoring using portable emissions monitoring systems (PEMS) are combined into a portable emissions or air toxicity system, for field deployment, including operation in moving vehicles. Cell cultures grown on 6mm inserts are placed in an airtight 17x13x9 cm exposure box, where the sample is symmetrically distributed into 8 wells of a standard Transwell 24-well holder at 25cm3/min/insert. In a 40x35x45 cm inner dimensions incubator, sample and control air are conditioned to 5% CO2, 37°C and >85% humidity and drawn through 2-4 exposure boxes. Characterization with silver nanoparticles revealed 50% particle losses at 15nm and deposition rate of approximately 1.5% at both 10 and 21nm mean diameter. The system has undergone an extensive field validation, including 4h of exposure and 2h transport in a vehicle each day for 5days, 5-day operation outside in vans and tents at -7 to +32°C, long transport and test on a heavy-duty truck, during which cells were exposed to the diluted exhaust from the truck, this being the first known use of ALI exposure chamber as PEMS. The portable exposure chamber, along with a field-deployable auxiliary mobile base including a small laminar flow box, additional incubator and freezer, can be easily used to study the toxicity of various emissions, effluents and polluted air, aiming for a more relevant toxicity measure than chemical composition alone.

Simple portable quantum key distribution for science outreach

Quantum key distribution (QKD) has become an essential technology in the realm of secure communication, with applications ranging from secure data transmission to quantum networks. This paper presents a simple, compact, and cost-effective setup for undergraduate tutorial demonstrations of QKD. It relies on using weak coherent pulses, which can be readily produced using an attenuated laser. The system employs the simplified three-state BB84 protocol in free space, with states encoded using linear polarization. Polarization encoding can be done passively or actively, depending on the budget available. Time multiplexing is implemented at the receiver to reduce the number of required detectors. Only two detectors are used to implement measurements on two bases, with a total of four outcomes. The result demonstrates the practicality of the system for free-space quantum communication, and its compact and portable nature makes it particularly suitable for pedagogical demonstrations. This work paves the way for engaging undergraduate students in the field of quantum communication through hands-on laboratory projects.

Portable Arbitrary Pulse Generator for Driving Microcoils for Micromagnetic Neurostimulation

Micromagnetic stimulation (μMS) is a promising branch of neurostimulation but without some of the drawbacks of electrical stimulation. Microcoil (μcoil)-based magnetic stimulation uses small micrometer-sized coils that generate a time-varying magnetic field, which, as per Faraday’s Laws of Electromagnetic Induction, induces an electric field on a conductive surface. This method of stimulation has the advantage of not requiring electrical contact with the tissue; however, these μcoils are not easy to operate. Large currents are required to generate the required magnetic field. These large currents are too large for standard test equipment to provide, and additional power amplifiers are needed. To aid in the testing and development of micromagnetic stimulation devices, we have created a compact single-unit test setup for driving these devices called the µCoil Driver. This unit is designed to drive small inductive loads up to ±8 V at 5 A and 10 kHz.

Homogeneous large field-of-view and compact iSCAT-TIRF setup for dynamic single molecule measurements

Interferometric scattering microscopy (iSCAT) enables prolonged and high frame rate single particle tracking (SPT) for studying molecular dynamics. Typical iSCAT setups employ conventional widefield or scanning illumination schemes. However, these implementations limit the field-of-view (FoV), the uniformity of the illumination and thus comparable accuracy over the whole FoV, and/or the maximum sampling rate, while in parts increasing hardware requirements and setup size. We demonstrate the realization of a large (60 µm x 60 µm) uniformly illuminated FoV through a passive refractive optical element in the iSCAT illumination path. This scanning-free iSCAT microscope setup is further combined with an objective based total internal reflection fluorescence microscopy (TIRF) channel for a complementary fluorescence readout, a focus-lock system, and a tailored control platform via the open-source ImSwitch software, and it has a compact footprint. As a proof-of-principle, we highlight the performance of the setup through the acquisition of iSCAT images with a uniform contrast and a constant ≤10 nm localization precision throughout the whole FoV. The performance is further demonstrated through dynamic iSCAT SPT and imaging fluorescence correlation spectroscopy (imaging FCS) of lipid diffusion in a model membrane system, highlighting the ability to track a large number of molecules with the same accuracy over a large FoV. Our iSCAT setup thus depicts an accurate and improved way of recording fast molecular dynamics in life sciences.

Miniaturized electrophoresis: An integrated microfluidic cartridge with functionalized hydrogel-assisted LAMP for sample-to-answer analysis of nucleic acid.

Accurate detection of pathogenic nucleic acids is crucial for early diagnosis, effective treatment, and containment of infectious diseases. It facilitates the timely identification of pathogens, aids in monitoring disease outbreaks, and helps prevent the spread of infections within healthcare settings and communities. We developed a multi-layered, paper-based microfluidic and miniaturized electrophoresis system for rapid nucleic acid extraction, separation, amplification, and detection, designed for resource-limited settings. Constructed from acrylic, transparency film, pressure-sensitive adhesion, and Whatman paper using a CO2 laser, the setup simplifies traditional methods and eliminates the need for complex equipment. DNA extraction and purification are achieved using Zweifach-Fung bifurcation and Fahraeus effect principles, with detection via a hydrogel-assisted colorimetric isothermal reverse transcriptase-loop-mediated isothermal amplification technique. The system accurately identified the SARS-CoV-2 N-gene and β-actin human gene, validated by a compact electrophoresis setup. In clinical validation with 12 patient specimens, the system demonstrated a positive predictive agreement of 83.0% and a negative predictive agreement of 100%. The system achieves a limit of detection of 1 copy/μl and can potentially transform nucleic acid detection assays in healthcare settings. This study addresses key challenges in nucleic acid detection, such as ensuring sample quality and quantity, reducing reliance on sophisticated equipment, preventing contamination, simplifying procedures, and providing rapid and accurate diagnostics for emerging pathogens.

Lateral shear interferometry for shape accuracy measurements of 3D-printed micro-optics

Abstract The technique of 3D-printed micro-optics has experienced significant advancements over the last few years [1, 2]. This progressive evolution has been marked by remarkable strides in precision and miniaturization, making it particularly attractive to applications in the field of medical endoscopy. One noteworthy application entails the fabrication of micro-lenses directly on optical fibers, thereby creating endoscopic devices with unparalleled capabilities. A significant attribute of these micro-optical systems lies in their capability for precise imaging and their adept navigation through exceptionally narrow biological structures. For instance, the application of the 3D-printed endoscopy technology has facilitated insertion into the aorta of mice, as well as severely diseased human carotid arteries [2, 3]. This unprecedented level of accessibility and adaptability holds immense promise for diagnostic and therapeutic interventions in the realm of cardiovascular medicine and beyond. In the future, it may also be conceivable for micro-lenses to serve not only as imaging tools, but also as integral components of 3D-printing processes aimed at repairing damaged human tissue with bio-materials. For micro-lens production and quality control, performance assessment is invariably necessary to assure diffraction limited imaging in the different optical applications. With confocal surface profiling, only the surface shape information of micro-optics can be obtained. However, not only the shape of 3D-printed optics is relevant for its quality, but also its refractive index distribution is crucial when determining its overall optical performance. Therefore, the measurement of the wavefront is decisive in evaluating lens performance. Lateral shear interferometry presents itself as a compact and precise method for wavefront measurements. The only essential component required in the set-up is a pair of glass plates with high surface quality. Consequently, the entire set-up can be notably streamlined, as there is no requirement to construct an interferometer reference arm. This advantage facilitates the development of a notably compact set-up, making lateral shear interferometry particularly advantageous for integration with microscope and 3D-printer, despite the requirement for more complex algorithms in analyzing lateral shear interferograms. In this paper, simulation of shear interferogram fringes corresponding to wavefronts exhibiting varying aberrations are discussed. Additionally, this research encompasses measurement and analysis of shear interferograms obtained from wave fronts transmitted through different lenses. Through meticulous examination of these experimental results, the characteristics and performance of the tested optical systems are elucidated, contributing to a deeper understanding of wavefront analysis methodologies and their applicability in optical characterization studies.

Development of a Compact Apparatus for Measuring Visually Induced Eye Movements in Larval Fish

Development of a Compact Apparatus for Measuring Visually Induced Eye Movements in Larval Fish

A Cylindrical Lens Spectrometer with Parallel Detection for Reflection Electron Energy Loss Spectroscopy.

Reflection electron energy loss spectroscopy (REELS) has played a pivotal role in allowing researchers to explore the characteristics of various bulk materials. This study presents results for the low-loss region of REELS with a new cylindrical lens spectrometer integrated into a low-voltage scanning electron microscope. The operational principles and implementation of the spectrometer are explained through comparisons between electron optical simulations and experimental results. Notably, the analysis shows the ability to distinguish samples in film and bulk forms. Graphene and graphite, despite their identical elemental composition and crystalline structure, are found to have distinct energy spectra as indicated by plasmon peaks. Furthermore, the study explores the bandgap measurement of SiO2 at low-energy conditions of 2.5 keV, highlighting the proposed instrument's advantages in the measurement without the harmful effect of Cherenkov loss. Additionally, this method reaffirms the capability to measure multiple plasmon peaks from the energy spectra of bulk gold samples, thus introducing a pioneering avenue in energy spectrum measurement. Leveraging the compact size and simple experimental setup of the spectrometer for REELS, the method enables the measurement of energy spectra of both bulk- and film-formed samples under low electron energy conditions, marking a significant advancement in the field.

Adjustable repetition rate mode-locked fiber laser using a ZnO nanolaminate

Adjustable repetition rate mode-locked fiber laser using a ZnO nanolaminate

Selection Criteria for Rotor Number and Rotational Direction in Arrays of Closely Spaced Darrieus Turbines

Abstract The efficiency gains observed in a pair of closely spaced Darrieus turbines suggest the deployment of multiple turbines as an appealing solution for wind and, particularly, hydrokinetic applications, where the inflow direction is constant. The present study develops some design guidelines for closely spaced hydrokinetic Darrieus turbines by analyzing the trends of both power augmentation and wake development within arrays of multiple rotors, including not only an even number of rotors, which is the usual case in literature, but also an odd one. The analysis is carried out by means of two-dimensional computational fluid dynamics simulations and includes not only the assessment of instantaneous blade forces but also locally sampled flow fields past each blade that allowed the reconstruction of dynamic polar data, contributing to a more comprehensive understanding of the physical mechanisms at play in such compact setups. The study demonstrates a consistent power augmentation mechanism across different layouts, even in the case of an odd number of rotors. This enhancement originates from flow blockage in the mutual interaction areas, favorably altering the inflow angle and subsequently increasing the angle of attack and lift generation. While this mechanism aligns with previous observations on arrays of counter-rotating pairs, its application to multiple turbines introduces complexities due to potential asymmetries in inflow, leading to an uneven power enhancement across turbines within the array. The identified efficiency improvement pattern suggests that maximizing leeward mutual interactions within an array of multiple Darrieus turbines would enhance the overall efficiency of the setup.

Antenna pattern reconstruction for mid-band massive antenna array based on a single-cut field transformation algorithm in a compact multi-probe anechoic chamber setup

ABSTRACT It has become a common challenge on how to measure radiation patterns of massive antenna arrays working at high frequency with high efficiency and accuracy, which has attracted huge interest from both academia and industry. In this paper, a highly accurate and efficient far field (FF) pattern reconstruction strategy through conducting single cut near field (NF) to FF transformation algorithm based on spherical wave expansion (SWE) is proposed for fast measurements of large base stations (BSs) operating at mid-band. Our objective is to design a compact multi-probe setup to measure key radiation parameters of the massive array, with low-cost and high-efficiency. A BS of 16 × 16 elements operating at mid-band is adopted as the device under test (DUT) in this paper. Analysis is conducted on the impact of measurement distance, sampling range and sampling density on the reconstruction accuracy of the algorithm in the compact multi-probe anechoic chamber setup, demonstrating that the required key information of the main lobe of the DUT can be accurately reconstructed when the measurement range R = 1/20 FF distance, sampling resolution ∆θ = 3°, and sampling range θ ∈ [75°, 105°] are selected, respectively. The impact of phase center offset on the accuracy of FF pattern reconstruction is analyzed when only one sub-array is enabled, demonstrating the effectiveness of the algorithm for sub-array measurements.

Светодиодное ультрафиолетовое облучение семян декоративных растений

The article presents studies on determining the effective dose of ultraviolet irradiation when processing seeds of ornamental plants in a compact unit. A promising branch of plant grow-ing is ornamental gardening, since ornamental plants are widely used in landscaping of populated areas. In ornamental gardening, western thuja and prickly spruce are used, which reproduce by seeds. Among all the methods of seed treatment before sowing, we give preference to LED ul-traviolet irradiation (UVR), as the simplest, energy-saving, energy-efficient, environmentally friendly method. The purpose of the study is to determine the effective dose of UV irradiation of seeds of ornamental plants prickly spruce (Picea pungens Engelm) and western thuja (Thuja occi-dentalis L) to increase the germination energy and seed viability. The experiment on UFO of seeds was carried out on a compact UV LED setup with an irradiance of 17.16 W/m2 and only in the UFO-A zone (315...400 nm). The experiment was repeated four times. Each experiment in-cluded 100 seeds. The highest germination energy and maximum seed germination of prickly spruce are observed at a UFO dose of 9.9 kJ/m2 (tfact.=4.71> ttable.=2.57 at P = 0.05). The highest values of germination energy and germination in western thuja occur at a UFO dose of 2.2 kJ/m2. UFO is a good stimulator of growth processes. This method is economically advanta-geous compared to traditional chemical stimulation of seeds, energy-efficient, and environmen-tally friendly because it does not pollute the soil. Keywords: LED IRRADIATION OF SEEDS, ORNAMENTAL GARDENING, THUJA OCCIDENTAL-IS, PRICKLY SPRUCE, ENERGY SAVING, ULTRAVIOLET, PRE-SOWING SEED TREATMENT

Novel Pharmaceutical Interventions for Drug Targeting in Parkinson’s Disease

Parkinson's Disease (PD) presents as a neurodegenerative disorder characterized by a gradual decline in brain function, typically advancing slowly over time in most individuals. However, as the disease evolves and impacts the Gastrointestinal Tract (GIT), the window for effective treatment response often becomes narrower for many patients. Recent advancements in medical science have spurred improvements in drug delivery, primarily through the development of enhanced oral formulations or the exploration of alternative administration routes, such as intestinal infusion, transcutaneous delivery, and inhaled levodopa. Among the recent oral formulation breakthroughs is IPX066, a novel formulation combining immediate and extended-release Carbidopa-Levodopa (CD/LD). Another notable example is levodopa-carbidopa intestinal gel, an authorized treatment involving the direct infusion of LD/CD suspension into the brain. Concurrent investigations are assessing the effectiveness of the 'accordion pill' (AP09004), an Extended-release (ER) LD/CD mixture designed to retain within the GIT for an extended period. Additionally, other formulations in various stages of clinical trials include ND0612, a proprietary liquid formulation intended for the purpose of subcutaneous delivery using a compact patch-pump apparatus, and CVT-301, a levodopa aerosol solution distinguished by its prompt initiation of therapeutic effects. However, several other promising formulations, such as DM-1992 and XP21279, have been terminated. This study aimed to thoroughly examine the pharmacokinetics, clinical effectiveness, and possible adverse reactions linked to innovative medication formulations that are now accessible or being developed for treating PD.

CsPbBr3 perovskite nanocrystals-based portable testing device for on-site detection of chloride ions from wastewater

CsPbBr3 perovskite nanocrystals-based portable testing device for on-site detection of chloride ions from wastewater