Search Results (243)

Background/Objectives: Historically, echocardiographic imaging of the right heart has been challenging because its abnormal geometry is not conducive to reproducible anatomical and functional assessment. With the development of advanced echocardiographic techniques, it is now possible to complete an integrated assessment of the right heart that has fewer assumptions, resulting in increased accuracy and precision. Echocardiography continues to be the first-line imaging modality for diagnostic analysis and the management of acute and chronic right heart failure because of its portability, versatility, and affordability compared to cardiac computed tomography, magnetic resonance imaging, nuclear scintigraphy, and positron emission tomography. Virtually all echocardiographic parameters have been well-validated and have demonstrated prognostic significance. The goal of this narrative review of the echocardiographic parameters of the right heart chambers and hemodynamic alterations associated with right ventricular dysfunction is to present information that must be acquired during each examination to deliver a comprehensive assessment of the right heart and to discuss their clinical significance in right heart failure. Methods: Using a literature search in the PubMed database from 1985 to 2025 and the Cochrane database, which included but was not limited to terminology that are descriptive of right heart anatomy and function, disease states involving acute and chronic right heart failure and pulmonary hypertension, and the application of conventional and advanced echocardiographic modalities that strive to elucidate the pathophysiology of right heart failure, we reviewed randomized control trials, observational retrospective and prospective cohort studies, societal guidelines, and systematic review articles. Conclusions: In addition to the conventional 2-dimensional echocardiography and color, spectral, and tissue Doppler measurements, a contemporary echocardiographic assessment of a patient with suspected or proven right heart failure must include 3-dimensional echocardiographic-derived measurements, speckle-tracking echocardiography strain analysis, and hemodynamics parameters to not only characterize the right heart anatomy but to also determine the underlying pathophysiology of right heart failure. Complete and point-of-care echocardiography is available in virtually all clinical settings for routine care, but this imaging tool is particularly indispensable in the emergency department, intensive care units, and operating room, where it can provide an immediate assessment of right ventricular function and associated hemodynamic changes to assist with real-time management decisions. Full article

Background and Objectives: Aortic stenosis (AS) leads to progressive left ventricular (LV) dysfunction, making early detection crucial. Global longitudinal strain (GLS) is an echocardiographic marker of subclinical LV dysfunction; however, echocardiography has limitations, including operator dependency and acoustic variability. Cardiac magnetic resonance (CMR) is a valuable complementary tool, and artificial intelligence (AI) may enhance strain measurement accuracy, though its role in AS remains underexplored. To evaluate the performance of an AI-based CMR feature tracking tool for the assessment of LV global and segmental GLS in AS patients and compare results with the respective measurements from healthy volunteers (control group), as well as with the GLS obtained using the echocardiographic speckle tracking technique. Materials and Methods: This retrospective study analysed 111 CMR exams (70 AS patients, 41 healthy controls) from a single centre. AI-derived GLS values from gradient echo 2-, 3-, and 4-chamber CMR views were manually reviewed for accuracy. Error rates, segmental, and global myocardial strain differences were assessed between AS patients and the control group. Results: AI-based CMR GLS strongly correlated with echocardiographic GLS (r = 0.694, p < 0.001) and showed lower variability. The AI-derived GLS from CMR was significantly lower in aortic stenosis patients compared to controls (−17.86 ± 3.47 vs. −20.70 ± 1.98). However, AI-based strain analysis had an overall error rate of 6%, which was significantly higher in AS patients (18.6%) compared to healthy controls (2.44%) (p = 0.0088). The 3-chamber CMR view was the most error-prone (50% of isolated errors). Segmental strain variability between AS patients and controls was most pronounced in basal segments, with smaller differences in middle and apical segments. CMR demonstrated greater precision than echocardiography, as indicated by a smaller standard deviation in GLS measurements (3.47 vs. 4.98). Conclusions: The AI-based CMR feature tracking technique provides accurate and reproducible GLS measurements, showing strong agreement with echocardiographic speckle tracking-based GLS. However, the higher error rates in AS patients compared to controls underscore the need for more advanced AI algorithms to improve performance in cardiac pathology. Full article

During the thermal analysis of hazardous materials, the thermal instruments available may face the risk of contamination within heating chambers or damage to the instruments themselves. Herein, this work introduces an innovative detection technology that combines thermogravimetric and differential thermal analysis with an integrated MEMS cantilever. Integrating polysilicon thermocouples and a heat-driven resistor into a single resonant cantilever achieves remarkable precision with a mass resolution of 5.5 picograms and a temperature resolution of 0.0082 °C. Validated through the thermal analysis of nylon 6, the cantilever excels in detecting nanogram-level samples, making it ideal for analyzing hazardous materials like ammonium perchlorate and TNT. Notably, it has successfully observed the evaporation of TNT in an air atmosphere. The integrated MEMS cantilever detection chip offers a groundbreaking micro-quantification solution for hazardous material analysis, significantly enhancing safety and opening new avenues for application. Full article

In this paper, an all-fiber light-induced thermoelastic spectroscopy (LITES) sensor based on hollow-core anti-resonant fiber (HC-ARF) and self-designed low-frequency quartz tuning fork (QTF) is reported for the first time. By utilizing HC-ARF as both the transmission medium and gas chamber, the laser tail fiber was spatially coupled with the HC-ARF, and the end of the HC-ARF was directly guided onto the QTF surface, resulting in an all-fiber structure. This design eliminated the need for lens combinations, thereby enhancing system stability and reducing cost and size. Additionally, a self-designed rectangular-tip QTF with a low resonant frequency of 8.69 kHz was employed to improve the sensor’s detection performance. Acetylene (C₂H₂), with an absorption line at 6534.37 cm⁻¹ (1.53 μm), was chosen as the target gas. Experimental results clearly demonstrated that the detection performance of the rectangular-tip QTF system was 2.9-fold higher than that of a standard commercial QTF system. Moreover, it exhibited an outstanding linear response to varying C₂H₂ concentrations, indicating its high sensitivity and reliability in detecting C₂H₂. The Allan deviation analysis was used to assess the system’s stability, and the results indicated that the system exhibits excellent long-term stability. Full article

Background/Objectives: Accurate patient-specific dosimetry is essential for optimizing radiopharmaceutical therapy (RPT), but current tools lack validation in clinically realistic conditions. This work aimed to develop a workflow for designing and fabricating patient-derived, organ-realistic RPT phantoms and evaluate their feasibility for commissioning patient-specific RPT radioactivity quantification. Methods: We used computed tomographic (CT) and magnetic resonance (MR) imaging of representative patients, computer-aided design, and in-house 3D printing technology to design and fabricate anthropomorphic kidney and parotid phantoms with realistic organ spacing, anatomically correct orientation, and surrounding tissue heterogeneities. We evaluated the fabrication process via geometric verification (i.e., volume comparisons) and leak testing (i.e., dye penetration tests). Clinical feasibility testing involved injecting known radioactivities of ¹⁷⁷Lu-PSMA-617 into the parotid and kidney cortex phantom chambers and acquiring SPECT/CT images. MIM SurePlan MRT SPECTRA Quant software (v7.1.2) reconstructed the acquired SPECT projections into a quantitative SPECT image and we evaluated the accuracy by region-based comparison to the known injected radioactivities and determined recovery coefficients for each organ phantom. Results: Phantom fabrication costs totaled < USD 250 and required <84 h. Geometric verification showed a slight systematic expansion (<10%) from the representative patient anatomy and leak testing confirmed watertightness of fillable chambers. Quantitative SPECT imaging systematically underestimated the injected radioactivity (mean error: −17.0 MBq; −13.2%) with recovery coefficients ranging from 0.82 to 0.93 that were negatively correlated with the surface-area-to-volume ratio. Conclusions: Patient-derived, 3D-printed fillable phantoms are a feasible, cost-effective tool to support commissioning and quality assurance for patient-specific RPT dosimetry. The results of this work will support other centers and clinics implementing patient-specific RPT dosimetry by providing the tools needed to comprehensively evaluate accuracy in clinically relevant geometries. Looking forward, widespread accurate patient-specific RPT dosimetry will improve our understanding of RPT dose response and enable personalized RPT dosing to optimize patient outcomes. Full article

Composite materials are increasingly used in various vehicles and construction parts, necessitating a comprehensive understanding of their behavior under varying thermal conditions. Measuring the thermo-mechanical properties with traditional methods such as tensile testing or dynamical mechanical analysis is often time-consuming and requires costly apparatus. This paper introduces an innovative non-destructive method for identifying the orthotropic engineering constants of composite test sheets as a function of temperature. The proposed technique represents an advancement of the conventional impulse excitation technique, incorporating an automated pendulum exciting mechanism and creating digital twins of the test sheets. The automated measurement of the impulse response function yields resonance frequencies and damping ratios at specified temperatures. These values are subsequently utilized in digital twins for identification of the engineering constants. The method is fully automated across predefined temperature intervals and can be seamlessly integrated into existing climate chambers equipped with remote control facilities. The results obtained from the described measurement technique were applied to a bi-directionally glass-reinforced thermoplastic PA6 matrix in a tested temperature range of −20 °C to 60 °C, revealing that the complex engineering constants are significantly affected by temperature. Full article

This study investigates wave-power extraction by an oscillating water column (OWC) device over a porous-to-rigid step bottom using linearized water-wave theory. The interaction between water waves and the OWC device is analyzed by solving the governing boundary-value problem with the eigenfunction expansion method (EEM) and the boundary element method (BEM). The study examines the effects of key parameters, including the porous effect parameter of the bottom, OWC chamber width, and barrier height, on the device’s efficiency. The results indicate that the porous effect parameter significantly influences OWC performance, affecting resonance characteristics and efficiency oscillations. A wider OWC chamber enhances oscillatory efficiency patterns, leading to multiple peaks of full and zero efficiency. The efficiency shifts towards lower wavenumbers with increasing step depth and barrier height but becomes independent of these parameters at higher wavenumbers. Additionally, incident angle plays a crucial role, decreasing efficiency at lower angles and exhibiting oscillatory behavior at higher angles. Furthermore, susceptance and conductance follow an oscillatory pattern concerning the gap between the porous bottom and the OWC chamber as well as chamber width. The porous effect parameter strongly modulates these oscillations. The findings provide new insights for enhancing OWC efficiency with complex bottom topography. Full article

The primary challenge in the design of offshore oscillating water column (OWC) devices lies in maintaining structural integrity throughout their operational lifespan while functioning in challenging environmental conditions. Simultaneously, it is vital for these devices to demonstrate efficiency in wave power absorption across a range of environmental scenarios pertinent to the selected installation site. The present manuscript seeks to compare two distinct mooring types for a dual-chamber OWC device to enhance its wave power efficiency. To accomplish this objective, an analysis of wave power absorption efficiency will be conducted on both a catenary mooring system and a tension-leg platform (TLP) mooring arrangement, thereby identifying the most suitable configuration. The study elucidates how OWC mooring characteristics influence wave power absorption efficiency. While the catenary mooring system exhibits two distinct resonant wave frequencies, resulting in enhanced wave power absorption at those frequencies, the TLP mooring system demonstrates superior overall wave power absorption efficiency across a broader range of wave frequencies, thus showcasing its greater potential for wave energy conversion under diverse environmental conditions. Full article

Background and Clinical Significance: Cardiac sarcoidosis (CS) is a rare but life-threatening disorder, occurring in 2–5% of sarcoidosis cases, though post-mortem studies suggest a higher prevalence. It presents diagnostic challenges due to nonspecific symptoms and the low sensitivity of an endomyocardial biopsy. Recent guidelines emphasize multimodal imaging, such as cardiac magnetic resonance imaging (MRI) and positron emission tomography (PET). Given the risk of heart failure (HF) and arrhythmias, early detection is critical. This case highlights the role of non-invasive imaging in diagnosing CS and guiding treatment. Case Presentation: A 54-year-old female with asthma, hyperlipidemia, a recent diagnosis of anterior uveitis, and familial sarcoidosis presented with dyspnea, chest tightness, and worsening cough. Examination revealed anterior uveitis, erythema nodosum, jugular venous distension, and pedal edema. The electrocardiogram (ECG) demonstrated bifascicular block and premature ventricular contractions (PVCs). The brain natriuretic peptide (BNP) was 975 pg/mL, with the transthoracic echocardiogram revealing a left ventricular ejection fraction of 25–30% with global LV akinesis. Coronary computed tomography angiography (CCTA) excluded coronary artery disease. Cardiac MRI showed late gadolinium enhancement, with PET demonstrating active myocardial inflammation, supporting a >90% probability of CS. Given her clinical trajectory and risk of further decompensation, immunosuppressive therapy was initiated without pursuing a biopsy. A dual-chamber implantable cardioverter defibrillator (ICD) was placed due to risk of ventricular arrhythmias. Bronchoalveolar lavage (BAL) showed a CD4/CD8 ratio of 6.53, reinforcing the diagnosis. She responded well to treatment, with symptom improvement and repeat imaging demonstrating signs of disease remission. Conclusions: This case underscores the growing role of multimodal imaging in CS diagnosis, potentially replacing biopsy in select cases. Early imaging-based diagnosis enabled timely immunosuppression and ICD placement, improving outcomes. Full article

The scientific community is showing growing interest in pulsed combustion technology due to its superior efficiency, environmental advantages, and diverse applications. Nevertheless, despite its promise, this technology remains underexplored because of its intricate nature and the numerous physicochemical mechanisms involved. This article introduces a pulse combustor, analyzing various power levels as a fundamental component. Each adjustment to operating parameters is shown to profoundly influence overall system behavior. This study advances pulse combustion technologies by addressing challenges, uncovering insights, and shaping future approaches to combustor design, with special attention to the critical role of resonance in the process. Key findings highlight the relationship between pressure fluctuations and temperature distributions, providing valuable insights for optimizing thermal management and enhancing combustor performance. Notably, the study reveals that the average pressure in the combustion chamber peaks at equivalence ratios close to the lower combustion limit ($\varphi$ = 0.5). These results point to the potential of advanced sensor systems and control mechanisms to dynamically optimize combustor operations, boosting efficiency and reliability in industrial contexts. The innovative strategies presented not only enhance fuel efficiency but also lay the groundwork for more adaptable combustor designs, meeting the critical demand for precise control in challenging environments. Full article

Micro-scale kinetic energy harvesters are in large demand to function as sustainable power sources for wireless sensor networks and the Internet of Things. However, one of the challenges associated with them is their inability to easily tune the frequency during the manufacturing process, requiring devices to be custom-made for each application. Previous attempts have either used active tuning, which consumes power, or passive devices that increase their energy footprint, thus decreasing power density. This study involved developing a novel passive method that does not alter the device footprint or power density. It involved creating a proof mass with an array of chambers or cavities that can be individually filled with liquid to alter the overall proof mass as well as center of gravity. The resonant frequency of a rectangular cantilever can then be altered by changing the location, density, and volume of the liquid-filled mass. The resolution can be enhanced by increasing the number of chambers, whereas the frequency tuning range can be increased by increasing the amount of liquid or density of the liquids used to fill the cavities. A piezoelectric cantilever with a 340 Hz initial resonant frequency was used as the testing device. Liquids with varying density (silicone oil, liquid sodium polytungstate, and Galinstan) were investigated. The resonant frequencies were measured experimentally by filling various cavities with these liquids to determine the tuning frequency range and resolution. The tuning ranges of the first resonant frequency mode for the device were 142–217 Hz, 108–217 Hz, and 78.4–217 Hz for silicone oil, liquid sodium polytungstate, and Galinstan, respectively, with a sub Hz resolution. Full article

The Helmholtz resonance acoustic metamaterial is an effective sound absorber in the field of noise reduction, especially in the low-frequency domain. To overcome the conflict between the number of Helmholtz resonators and the volume of the rear cavity for each chamber with a given front area of single-layer metamaterial, a novel acoustic metamaterial of interlayer parallel connection of multiple Helmholtz resonators (IPC–MHR) is proposed in this study. The developed IPC–MHR consists of several layers, and the Helmholtz resonators among different layers are connected in parallel. The sound absorption property of IPC–MHR is studied by finite element simulation and further optimized by particle swarm optimization algorithm, and it is validated by standing wave tube measurement with the sample fabricated by additive manufacturing. The average sound absorption coefficient in the discrete frequency band [200 Hz, 300 Hz] U [400 Hz, 600 Hz] U [800 Hz, 1250 Hz] is 0.7769 for the IPC–MHR with four layers. Through the optimization of the thickness of each layer, the average sound absorption coefficient in 250–750 Hz is up to 0.8068. Similarly, the optimized IPC–MHR with six layers obtains an average sound absorption coefficient of 0.8454 in 300–950 Hz, which exhibits an excellent sound absorption performance in the low-frequency range with a wide band. The IPC–MHR can be used to suppress obnoxious noise in practical applications. Full article

Despite extensive research on the performance of Oscillating Water Columns (OWC) over the years, issues with low energy conversion efficiency and unstable power generation have not been addressed. In this study, a novel OWC energy conversion system is proposed based on the working principle of energy storage valve control. The system utilizes accumulators and valve groups to enhance the stability of energy conversion. The hydrodynamic model of the OWC system and the pneumatic model of the novel power take-off (PTO) system are developed using numerical simulations. Building on this, the impact of the incident wave period, wave height, and air chamber opening ratio on the system’s total hydrodynamic performance are examined. The results from the hydrodynamic analysis are subsequently used as input conditions to evaluate the proposed PTO system’s performance. The results show that the hydrodynamic efficiency of the system presents a tendency to increase and then decrease with the increase in the incident wave period, and an optimal period exists. The air chamber opening ratio has a notable influence on the hydrodynamic characteristics of the OWC system, and the larger system damping could be set to achieve a higher capture efficiency in the low-frequency water environment. The incident wave height has a lesser effect on the hydrodynamic characteristics and the resonant period of the device. The designed novel PTO system can effectively improve the energy conversion stability of the OWC device, the flow volatility through the turbine can be reduced by 53.49%, and the output power volatility can be reduced by 25.46% compared with the conventional PTO system. Full article

In this paper, enhanced rotational circulation in a circular microfluidic chamber driven by dual focused surface-acoustic-wave (SAW) beams is presented. To characterize the resonant frequency and focusing effect, we simulate the focused SAW field excited by an arc-shaped interdigital transducer patterned on a 128°Y-cut lithium-niobate (LiNbO₃) substrate using a finite element method. A full three-dimensional perturbation model of the combined system of the microfluidic chamber and the SAW device is conducted to obtain the acoustic pressure and acoustic streaming fields, which show rotational acoustic pressure and encircling streaming resulted in the chamber. Accordingly, the SAW acoustofluidic system is realized using microfabrication techniques and applied to perform acoustophoresis experiments on submicron particles suspending in the microfluidic chamber. The result verifies the rotational circulation motion of the streaming flow, which is attributed to enhanced angular momentum flux injection and Eckart streaming effect through the dual focused SAW beams. Our results should be of importance in driving particle circulation and enhancing mass transfer in chamber embedded microfluidic channels, which may have promising applications in accelerating bioparticle or cell reactions and fusion, enhancing biochemical and electrochemical sensing, and efficient microfluidic mixing. Full article

Solid waste recycling challenges civil and environmental engineers to use waste from different industries to exceed sustainable development while meeting current material costs. Combustion slag (CS) is the material resulting from the combustion of hard coal in pulverized coal boilers. It is removed by gravity from the furnace chamber and transported by hydraulics through the slugger to the sedimentation chambers and from there to the heaps. The waste combustion slag can be used for land leveling, road building, and sports and leisure facilities. This paper presents the geomechanical characterization of the CS from the “Siekierki” CHP Plant, located in Warsaw, Poland. Particular emphasis was placed on the dynamic properties of combustion slag, including shear modulus (G) and damping ratio (D). Correct estimation of these parameters over a wide strain range is essential for laboratory research and modeling. A laboratory test program was defined to obtain the G-modulus, G_max-modulus, shear modulus degradation curve G(γ)/G_max, D-ratio, depending on the mean effective stress and relative density, in the strain range of 10⁻⁶ up to 10⁻³. Stiffness of CS was obtained using laboratory investigations typical for natural soils, namely, standard resonant column tests, and bender element tests. From the many different methods for soil damping estimation, two of the most common were selected: logarithmic decay and half-power bandwidth. The dynamic properties and their changes with strain of the Siekierki combustion slag are in line with general trends for granulated natural soils and other recycled materials. The outcomes of the presented research promote the reuse of CS as aggregate in road construction, which contributes to limiting the extraction of natural aggregate, reducing the filling of lands with this type of waste, and ultimately reducing the transport of materials and consequently lowering greenhouse emissions. Full article