Compact Unit Research Articles

Picometer sensitive prototype of the optical truss interferometer for LISA

Abstract The optical truss interferometer (OTI) is a contingent subsystem proposed for the LISA telescopes to aid in the verification of a 1 pm Hz optical path length stability. Each telescope would be equipped with three pairs of compact fiber-coupled units, each forming an optical cavity with a baseline proportional to the telescope length at different points around the aperture. Employing a Pound–Drever–Hall approach to maintain a modulated laser field on resonance with each cavity, the dimensional stability of the telescope can be measured and verified. We have designed and developed prototype OTI units to demonstrate the capability of measuring stable structures, such as the LISA telescope, with a 1 pm Hz sensitivity using a set of freely mountable fiber-injected cavities. Aside from its initial motivation for the telescope, the OTI can also be readily integrated with other systems to aid in ground testing experiments. In this paper, we outline our experimental setup, measurement results, and analyses of the noise limitations.

Bandwidth enhancement of resonating absorber using a lossy dielectric layer for RCS reduction in X-band

Abstract In this paper, a resonating absorber is proposed for radar cross section reduction in the X-band, with the inclusion of a high loss dielectric layer. The absorber consists of a pair of co-centered resonating Jerusalem cross printed on a FR4 substrate cascaded with a high-loss dielectric layer and a metallic back plane. The designed absorber offers 90 % absorption from 7.8–12 GHz with a fractional bandwidth of 42.42 %. The designed absorber is 0.106λ L thick with a compact square unit cell of size 0.076λ L (wavelength at the lowest frequency). An equivalent circuit model is developed to analyze the proposed absorber. The absorber is angularly stable for varying angle of incidences up to 40°–60° for TE and TM polarizations respectively. The planar as well as the conformal structure of the proposed absorber offer a minimum 10 dB radar cross section reduction in the X-band. The conventional approach which involves complex fabrication process of soldering thousands of lumped resistors to increase the bandwidth, whereas the proposed absorber is realized to offer wide absorption using simple PCB etching technique. To validate the design prototype is fabricated and the measurement is carried out.

OoTrap: enhancing oocyte collection and maturation with a field-deployable fluidic device.

Assisted reproductive technologies (ART) are pivotal for contemporary reproductive medicine and species conservation. However, the manual handling required in these processes introduces stress that can compromise oocyte and embryo quality. This study introduces OoTrap, a novel fluidic device designed to streamline ART workflows by facilitating the capture and maturation of oocytes in a compact unit. The device also reintroduces mechanical forces similar to those in the in vivo environment, which are often missing in conventional systems. OoTrap operates in both static and perfusion-based modes, offering flexibility and optimal conditions for oocyte maturation. Notably, OoTrap achieved higher in vitro maturation (IVM) rates under perfusion, produced oocytes with fewer chromosomal abnormalities, and maintained spindle morphology integrity. The incorporation of a heating system and a 3D-printed syringe pump enabled IVM outside the incubator, making OoTrap suitable for field applications. The results highlight the potential of OoTrap to enhance ART outcomes by reducing manual handling, providing a controlled microenvironment, and offering a practical solution for field-based ART applications.

Modelling and Simulation for a Versatile Controllable Power Supply Configuration Appropriate for Magnetically Impelled Arc Butt (MIAB) Welding

This article presents the design and development of a power source for industrial applications, focusing on improving energy efficiency, control, and reliability. The study is primarily focused on designing an optimized electrical power source for Magnetically Impelled Arc Butt (MIAB) welding, which is a solid-state welding process characterized by specific current requirements. MIAB welding involves variation of current in two stages of the welding sequence. The objective of this study is to propose an appropriate power supply configuration that meets the precise amperage control and also ensures machine compactness and automation of the process. Utilizing state-of-the-art simulation tools, the research explores various design parameters and configurations to achieve the desired current modulation efficiently. The inverter-based welding power source is tested for the welding of tubes of MS1018 material by implementing parametric variations to validate its workability and performance. The findings indicate that the proposed power supply configuration can enable the required control and also provide a compact power supply unit for MIAB welding, paving the way for its broader industrial adoption and implementation. This research contributes to the advancement of welding technology by providing a robust solution to the challenges associated with arc dynamics and amperage modulation in MIAB welding, ultimately leading to improved weld quality and process efficiency. The proposed power supply design demonstrates potential applications well beyond MIAB welding, offering versatility for any process requiring controlled amperage variation during its operation cycle.

A Compact Piezo-Drive Rotatable Scanning Tunneling Microscope in a 12 T Cryogen-Free Magnet.

Atomically resolved scanning tunneling microscope (STM) capable of insitu rotation in a narrow magnet bore has become a long-awaited but challenging technique in the field of strong correlation studies since it can introduce the orientation of the strong magnetic field as a control parameter. This article presents the design and functionality of a piezoelectrically driven rotatable STM (RSTM), operating within a 12 T cryogen-free magnet and achieving a base temperature below 1.8 K, along with spectroscopic capabilities. The system features a compact STM head unit that combines an inertia drive shaft with spring clamping onto the inner wall of a slender piezoelectric scanning tube (PST), enabling both stepper and scanner functionality while reducing the STM's size to 25.5 mm in length and 9 mm in diameter, facilitating rotation within the magnet bore. Another linear piezoelectric motor, driven by a PST, employs a mechanical linkage to convert linear into rotational motion, driving the STM head unit coaxially aligned with it. This mechanism enables STM accurate rotation, offering angle control from 0° to 90° with an ideal closed-loop accuracy of 0.11° per 0.01 V, as determined by a calibrated Hall sensor. Compact and suspended as a standalone unit at the tail of the sample probe, the RSTM is effectively shielded from external mechanical vibrations via secondary counterweight damping. To validate the device performance, the topographic images of graphite and NbSe2 and their spectroscopy at various magnetic field orientations up to 12 T and temperatures below 1.8 K are obtained. The compact and vibration-resistant RSTM provides compatibility with ultra-high-field water-cooled magnets, facilitating investigations into multiangle magnetic field modulation studies for condensed matter physics.

Compact non-contact temperature measurement device for high-intensity microwave electromagnetic fields conditions

The practical implementation aspects of heated in microwave electromagnetic fields objects noncontact temperature measurement as one of the main factors in ensuring the quality of the heat-treated product are considered. The advantages of using the pyrometric method of temperature measurement in comparison with the thermocouple method under the influence of high-intensity electromagnetic fields are substantiated. A variant, which includes a cut-off waveguide with fasteners and a small-sized infrared sensor, for continuous temperature measurement system technical implementation of heated in a microwave field objects is proposed. The variants of proposed compact, cheap and versatile temperature measurement unit using a single-zone infrared sensor of the MLX90614 family, in application to conveyor microwave heating installations are described. The convenience of embedding the sensor into the microwave technological installation control system is noted due to the presence of programming functions for the emissivity of the measured object, the possibility of transmitting information about the object temperature using one of two digital protocols, as well as the possibility of building a network of several dozen measuring sensors on one two-wire digital data bus. The small size and weight, simplicity and relative cheapness of the contactless temperature measurement unit design allows it to be used in all types of microwave heating devices.

Dynamic treatment units in forest planning improves economic performance over stand-based planning

AbstractHigh-resolution, wall-to-wall forest information enables precision-driven decision-making in forest management planning. In a case study we compare planning approaches using such information for solving long-term forest planning problems. The two first approaches are based on dynamic treatment unit (DTU) planning with high-resolution cells (12.5 × 12.5 m2) or segments (0.27 ha on average), respectively, solved with a cellular automata heuristics. The third approach is a traditional stand-based approach using stands (5.2 ha on average) and linear programming to solve the planning problem. Fixed costs associated with cutting operations are quantified as each treatment unit is charged with an entry cost of 10 000 SEK. The entry costs are included in the DTU approach while in the stand approach entry costs are applied accordingly in a post-optimization routine. In large, the analyses are based on open-access tools and data provided by Swedish authorities. The traditional stand approach produced plans with 5.2–2.7% lower net present value compared to DTU planning. Most of the differences were caused by greater suboptimal losses in plans produced with the stand approach, but entry costs were also lower in DTU plans. While forestry was less profitable, treatment units were more spatially compact with stands, especially compared to cell-based plans. Therefore, we reason that a combination of modelling of direct costs and use of spatial proxy variables, such as common border length, may be advisable in DTU planning to achieve compact and realistic treatment units. Finally, the results indicate that high-resolution data and DTU planning may better utilize forests’ potential of economic production, compared to the traditional stand approach.

Restorative Interior Design to Renew Attention and Reduce Stress in Small Residential Units

The shift in lifestyle due to urbanization and the recent pandemic has increased demand for small residential units suitable for remote work and longer stays. Restorative environments have gained importance within these spaces as they impact productivity, reduce fatigue, and alleviate stress. This study aims to identify effective restorative environments for small residential units, deepening our current understanding about contributions of interior design to personal well-being. Six virtual models combining Rectilinear and Curvilinear forms with Minimal, Natural, and Rustic styles were created. A total of 89 participants with lockdown or remote work experience evaluated these environments using VR devices and a PRS questionnaire. Results showed higher ratings for all virtual restorative environments compared to the non-restorative control design. The Rectilinear form with Minimal style and Curvilinear form with Natural style received the highest ratings. Surprisingly, nature analogues using curves and natural materials did not produce expected outcomes, highlighting the importance of integrating natural elements, considering individual preferences, and ensuring environmental coherence for enhanced restorative attributes. Creating an effective restorative environment extends beyond incorporating nature-based elements. These findings offer insights for designing residential spaces that boost well-being and productivity, especially in the context of remote work and extended stays in compact residential units.

Quantum sensing of acceleration and rotation by interfering magnetically launched atoms.

Accurate and stable measurement of inertial quantities is essential in geophysics, geodesy, fundamental physics, and inertial navigation. Here, we present an architecture for a compact cold-atom accelerometer-gyroscope based on a magnetically launched atom interferometer. Characterizing the launching technique, we demonstrate 700-parts per million gyroscope scale factor stability over 1 day, while acceleration and rotation rate bias stabilities of 7 × 10-7 meters per second squared and 4 × 10-7 radians per second are reached after 2 days of integration of the cold-atom sensor. Hybridizing it with a classical accelerometer and gyroscope, we correct their drift and bias to achieve respective 100-fold and 3-fold increase on the stability of the hybridized sensor compared to the classical ones. Compared to a state-of-the-art atomic gyroscope, the simplicity and scalability of our launching technique make this architecture easily extendable to a compact full six-axis inertial measurement unit, providing a pathway toward autonomous positioning and orientation using cold-atom sensors.

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

From Fiber Layout to the Sensor: Preparation Methods as Key Factors for High-Quality Coupled-Core-Fiber Sensors.

During recent years, the optical-fiber-based simultaneous sensing of strain and temperature has attracted increased interest for different applications, e.g., in medicine, architecture, and aerospace. Specialized fiber layouts further enlarge the field of applications at much lower costs and with easier handling. Today, the performance of many sensors fabricated from conventional fibers suffers from cross-sensitivity (temperature and strain) and relatively high interrogation costs. In contrast, customized fiber architectures would make it possible to circumvent such sensor drawbacks. Here, we report on the development of a high-quality coupled-core fiber and its performance for sensors-from the initial fiber layout via elaboration of the preform and fiber up to the sensor evaluation. A compact, high-speed, and cost-effective interrogation unit using such a specialized coupled-core fiber has been designed to monitor reflectivity changes while even being able to distinguish the direction of the force or impact. Several fiber core material techniques and approaches were investigated, which made it possible to obtain a sufficient volume of material for the required fiber core number and a specialized fiber core geometry in terms of core distances and radial refractive index profile, whilst handling the non-symmetrical fiber architectures of such modeled, complex structures and balancing resources and efforts.

Dynamic Response of a Rotor Supported on Hybrid Bearings in Air, Water, and Liquid Nitrogen: Measurements and Comparisons to Predictions

Abstract Modern liquid rocket engine turbopumps implement hybrid bearings, which combine hydrostatic and hydrodynamic fluid film principles, in compact and lightweight units known for their superior reusability, durability, and reliability. This study aims to provide extensive and reliable test data for the purpose of anchoring and benchmarking predictive tools for these bearings. This paper provides comprehensive dynamic response measurements of a rotor weighing 10.40 kg and approximately 60 mm in diameter at the bearing locations. The test rotor is supported on two hybrid journal bearings with a bearing length to bearing diameter ratio of approximately 0.42 and a bearing radial clearance to rotor radius ratio of around 0.0017. The bearings are tested with air, water, and liquid nitrogen, serving as surrogate test fluids for common propellants in liquid rocket engines. Rotor run-up and speed coast-down tests are conducted to measure shaft motion responses. The results clearly demonstrate that the rotordynamic characteristics of the test rotor supported on the hybrid journal bearings largely rely on properties of the test fluids and their feeding conditions. Notably, when air is pressurized into the test bearings, the shaft motion responses differ markedly from those observed with water and liquid nitrogen, primarily due to significantly lower stiffness and damping coefficients. Furthermore, rotor speed coast-down tests for each test fluid exhibit notable differences in coast-down speed over time characteristics, depending on the test fluid properties. The predicted rotor imbalance responses exhibit excellent correlation with the measurement data. The steady increase of demand and growth of the fluid film bearing technology for reusable rocket engines require accurate bearing design tools, the extensive component testing, and the implementation of the technology. The validated and developed bearing predictive models from previous research demonstrate well the characteristics of bearings under various operating fluids conditions. The findings and database presented in this work contribute not only to comprehending the performance of hybrid bearings but also to understanding and enhancing the dynamic characteristics of rotor systems supported on hybrid bearings.

A microwave permittivity sensor on a Mach–Zehnder Interferometer of: Spoof surface plasmon polariton waveguides

A microwave Mach–Zehnder Interferometer (MZI) sensor for the permittivity characterization of liquids is presented in this paper. Two spoof surface plasmon polariton (SSPP) waveguide transmission lines (TLs) composed of compact spiral units is utilized in a differential architecture. Loading a dielectric material on the sensing arm induces a phase difference between the two arms, leading to periodic interference dips on the transmission curve. The spectral positions and magnitudes of these dips change with different dielectric materials. Due to the nonlinear dispersion characteristics of the SSPP TL, the proposed SSPP-based MZI sensor achieves improved sensitivity compared with microstrip-based MZI sensor. To validate the sensor’s performance, six different oil samples and a set of adulterated oils were measured, incorporating a polydimethylsiloxane (PDMS) channel on the sensing arm. The variations in the spectral position and magnitude of the interference dip centered at 3.2 GHz are employed to determine the dielectric constants and loss tangents of the tested oils. The sensitivity in measuring the dielectric constant is 3.61 %. The maximum errors for measuring the dielectric constant and the loss tangent are 4.3 % and 6.7 %, respectively. Compared to other sensors for liquid oil detection, the proposed sensor provides a relatively high sensitivity while maintaining a low liquid volume, making it a promising candidate for permittivity measurements of liquid analytes and solid materials with similar dielectric constants.

Simulation-aided development of a compact local ventilation unit with the use of CFD analysis

Simulation-aided development of a compact local ventilation unit with the use of CFD analysis

Enhancing sludge thickening in continuous treatment using polymeric bubbles with cationic polymer P2900 and cocamidopropyl betaine.

Sludge thickening is a fundamental stage of treatment. This study investigated the application, in continuous treatment, of polymeric bubbles produced with cationic polymer P2900 and cocamidopropyl betaine (CAPB), a zwitterionic surfactant. The proposed reagent combination aims to form aerated flakes, solid waste structures, and rapidly rising air bubbles, ideal for treatments in compact units. Using this combination, it was possible to achieve a total solids concentration of 45% with the modified bubbles and 25% with the conventional water treatment. This level of thickening occurred under the following operating conditions: initial total solids (TS) concentration of 10g L-1, a flow rate of 5 L min-1, saturation pressure (psat) of 3atm, and polymer dosage of 10mg (gTS)-1. The suggested mechanism of action involves the adhesion of P2900 molecules to CAPB at the air/water interface, forming a lining on the bubble surface. Additionally, polymerized species form due to the residual aluminum (Al) in the sludge, which would occur during flocculation in the helical tubular flocculator (HTF), adsorbing the micelles and bubbles of CAPB. The critical micellar concentration (CMC) of CAPB was 0.26mmol L-1. Polymeric bubble technology can provide an efficient and cost-effective approach to sludge thickening in continuous treatment.

GROWING OF GREEN CORAL LETTUCE AND RED HYBRID TILAPIA IN COMPACT AQUAPONIC PROTOTYPE AT DIFFERENT RECIRCULATION RATES

In this work, a compact-size aquaponics prototype was designed and fabricated. One of the current challenges in compact aquaponics systems is optimizing the balance between fish waste production and plant nutrient uptake. The objective of the work is to assess the impact of different pump recirculation rates on the crops cultivation at such compact aquaponics unit. Main components included a 50 litres fish tank, a filter unit that combines the mechanical filter and biological filter counterparts, and nutrient film technique (NFT) grower. Production of food was carried out for 10 weeks at two different recirculation rates i.e. at 50 L/hr and 75L/hr. According to the data attained, the specific growth rate (SGR) was around 5.4-5.7% with a food conversion ratio (FCR) of about 1.8-2. Moreover, the fish survival rate was 80%, and plant growth yield is about 1.5-2 cm/week. Although the level of ammonia was slightly off the acceptable limit, no yellowish colour on the leaves of the green coral lettuce was observed. The data attained signify the successful operation of compact-size aquaponics for the production of organic leafy plants and freshwater aquaculture.

MCM2-7 loading-dependent ORC release ensures genome-wide origin licensing

Origin recognition complex (ORC)-dependent loading of the replicative helicase MCM2-7 onto replication origins in G1-phase forms the basis of replication fork establishment in S-phase. However, how ORC and MCM2-7 facilitate genome-wide DNA licensing is not fully understood. Mapping the molecular footprints of budding yeast ORC and MCM2-7 genome-wide, we discovered that MCM2-7 loading is associated with ORC release from origins and redistribution to non-origin sites. Our bioinformatic analysis revealed that origins are compact units, where a single MCM2-7 double hexamer blocks repetitive loading through steric ORC binding site occlusion. Analyses of A-elements and an improved B2-element consensus motif uncovered that DNA shape, DNA flexibility, and the correct, face-to-face spacing of the two DNA elements are hallmarks of ORC-binding and efficient helicase loading sites. Thus, our work identified fundamental principles for MCM2-7 helicase loading that explain how origin licensing is realised across the genome.

Design and optimization of a combi boiler heat exchanger: A CFD-based approach

Heat exchangers are widely used in various fields, emphasizing the importance of efficiency and mass/dimensional improvements. Aluminum boiler heat exchangers play a crucial role in systems, where the natural gas-air fuel mixture is burned and heat transfer to water occurs. In such heat exchanger designs, the region where the air-gas mixture burns is referred to as the “combustion chamber,” and the thermal energy produced is transferred to the circulating water in the body.In this study, it was aimed to improve the heat transfer per unit surface by using novel pin–fin geometries in DAIKIN NDJ 24 kW aluminum cast boiler heat exchanger, thus reducing and lightening the dimensions of the combi heat exchanger for the same thermal performance. This approach targets cost reduction in production and downsizing of the boiler dimensions for more compact units. Cleanability limit was also established, and a unique symmetric droplet model was optimized utilizing a Computational Fluid Dynamics (CFD) based Response Surface Methodology (RSM) approach. Predictions of thermal performance through CFD simulations were subsequently validated experimentally using test bench available at DAIKIN’s facility in Sakarya, Türkiye. The results demonstrated a remarkable of 14% reduction in the overall weight, which was achieved by shortening the combi boiler height by 26 mm, while preserving the same efficiency levels. This research underscores the potential of the innovative pin geometry and optimized droplet model to enhance the efficiency and performance of the heat exchanger, with implications for cost savings and improved manufacturing processes. Also the effect of the new pin-fin geometry on the condensation performance was investigated as a multiphase phenomenon for the first time in the international literature. The results showed an excellent agreement between predicted and measured performance data.

A new miniaturized Split-Ring Resonator-Based inverse double Sigma-Shaped artificial material for Penta-Band wireless communication

This paper discusses a study on creating and confirming the authenticity of an artificial material with a SNG (Singular Negative) attribute. The artificial material was constructed using a metamaterial structured around split-ring resonators forming an inverse double sigma shape. Advanced electromagnetic simulation tools like CST (Computer Simulation Technology) Microwave Studio, Ansys HFSS (High Frequency Structure Simulator) and ADS (Advanced Design System) were employed to extensively analyze the electromagnetic characteristics of the artificial material. Notably, the proposed artificial material exhibits five distinct resonance frequencies spanning L-, S-, C-, X-, and Ku-band operations, specifically at 1.560 GHz, 2.232 GHz, 4.350 GHz, 8.095 GHz, and 17.370 GHz. Achieving an optimal EMR (Effective Medium Ratio) of 23.45, with a compact unit cell size of 8.2 mm × 8.2 mm and a substrate thickness of 1.905 mm, underscores its innovative design attributes. Of significance, the compact size, SNG characteristics, high EMR, and resonant frequencies render this structure particularly noteworthy. The utilization of the L-band for GPS (Global Positioning System), S-band for Wireless LAN (Local Area Network), C-band for Satellite communication, X-band radar system, and the Ku-band for VSAT (Very Small Aperture Terminal) communication applications is well-documented. This article elucidates the intricacies of the design process and conducts various parametric analyses. Remarkably, the simulation results obtained from Ansys HFSS 3D software closely align with those from CST. Furthermore, a comprehensive examination of surface current, E-field, and H-field distributions is provided. Importantly, comparative assessments indicate the superior performance of the proposed structure across multiple metrics, including EMR, SNG frequency range, and compactness, positioning it as an ideal candidate cellular phone, satellite, and radar-based applications.

Scaling up a hollow fibre adsorption unit for on-board CCS applications using a real gasoline engine exhaust

Decarbonising road transport using on-board carbon capture and storage (CCS) is challenged by inherent space and energy limitations. Thus, to be technically and economically viable, robust and compact carbon capture units need to be developed. Hence, in this work, a scaled up hollow fibre adsorption unit was tested downstream of a real 90:10 gasoline-ethanol engine exhaust gas to evaluate its CO2 capture performance after 100 adsorption–desorption cycles. The scaled up hollow fibre adsorption unit consisted of 37 four-channel hollow fibre adsorption units coated with a thin carbon xerogel layer, referred to as the CX-coated hollow fibre module (HFM). It should be noted that this is the first study to report the results of a HFM tested under real conditions over 100 adsorption–desorption cycles and is one of the few studies that reports the desorption step. Furthermore, despite the presence of CO, THC, NOx, and H2O in the exhaust gas, the CX-coated HFM exhibited high CO2 capture stability and mechanical integrity. This was evidenced through the CX-coated HFM obtaining and maintaining an average total capacity of 1.2 mmol/g over 100 adsorption–desorption cycles, and showing no visible signs of deterioration or a loss of mechanical integrity.