Effect Of Compression Research Articles

Effect of vessel compression on blood flow in microvascular networks and its implications for tumour tissue hypoxia

The tumour microenvironment is abnormal and one of its consequences is that blood vessels are compressed. Vessel compression correlates with reduced survival rates, while decompression of vessels improves tissue oxygenation as well as increases survival rates. Vessel compression contributes, at a single vascular bifurcation, to the increase of heterogeneity of red blood cell (RBC) transport. However, the effect that vessel compression has at a network level is unknown. This work numerically investigates the effect of vessel compression on RBC transport in microvascular networks. The key findings are that vessel compression both reduces the average haematocrit, and increases haematocrit heterogeneity, in vessels in the network. The mechanisms for these changes in haematocrit distribution are unravelled, and a parameter sweep shows that networks with lower inlet haematocrits are more susceptible to haemodilution from vessel compression over a wide range of compressed fraction of a network. These findings provide a theoretical underpinning for the link between vessel compression and tumour tissue hypoxia.

Numerical investigation of cavitation vortex dynamics in different cavitation patterns coupled implicit large eddy simulation and boundary data immersion method

The objective of this paper is to investigate the flow characteristics of different cavitation flow patterns around a NACA (National Advisory Committee for Aeronautics) 66 hydrofoil by applying the BDIM (boundary data immersion method) and ILES (implicit large eddy simulation) with an artificial code. Meanwhile, an artificial compressibility method is also employed to consider the effects of compressibility on cavitating flow. The results present that the numerical method can effectively capture different cavitation patterns, which agrees well with the previous experimental data. Subsequently, the detailed analysis of vortex structures and dynamics for the non-cavitation (σ = 3.0), sheet cavitation (σ = 2.0), and cloud cavitation (σ = 1.6) cases with the Liutex method and the vortex enstrophy transport equation have been investigated. When cavitation occurs, the degree of turbulence and the enstrophy in the flow field have been enhanced, due to the disturbance of the velocity field. For sheet cavitation, complex vortex structures appear in the attached cavity region with high-intensity enstrophy causing by the highly intense velocity and density gradient. As the cavitation pattern transits from the sheet cavitation to the cloud cavitation, more complex vortex structures can be observed in the cavitation region. Furthermore, the value and the fluctuation amplitude of enstrophy intensity increase significantly under the effect of reentrant jet. Analysis of the enstrophy transport equation indicates that the vortex stretching term and dilatation term for cloud cavitation increase relatively significantly with the movement of the reentrant flow and are highly dependent on the cavitation evolution. In addition, the region affected by the baroclinic torque also increases.

Effects of external limb compression and/or low‐load resistance exercise on post‐activation performance enhancement during countermovement jumps

AbstractThe effects of low‐load resistance exercise combined with external limb compression (ELC) to augment post‐activation performance enhancement during countermovement jumps have yet to be examined. We assessed the separate and combined effects of ELC and sets of low‐load (back squats) resistance exercise (both compared with controls) during conditioning routines, and determine their subsequent neuromechanical consequences during countermovement jumps. On separate days, twenty strength‐trained men completed a familiarization session followed by four experimental trials in a randomized design that included one of the following conditioning routines: passive rest (Control [CON], no occlusion/standing), exercise (sets of low‐intensity resistance exercise [RE] with 30% 1RM, no occlusion/exercise), ELC ([ELC] at 80% of the individual arterial occlusion pressure, occlusion/standing), and combined ELC and exercise ([ELC + RE], occlusion/exercise). Countermovement jump performance (jump height, relative peak power output, vertical impulse, and rate of force development) was assessed at baseline, immediately after, and at the third, sixth, ninth and twelfth minute following each conditioning routine. Compared to baseline, jump height, relative peak power output and vertical impulse values were lower at 0 min for [RE] (−3.5%–8.2%; p ≤ 0.014) and higher at +3 min for [ELC] (+2.0%–3.8%; p ≤ 0.013). Regarding [ELC + RE], values for these three variables were lower at 0 min (−4.8%–8.0%; p < 0.001) but higher at +12 min (+2.9%–5.5%; p < 0.001) versus baseline. In strength‐trained men, using ELC either alone (while standing) or combined with low‐load resistance exercise sets (during back squats) can be a useful way to improve CMJ mechanics. However, the duration and magnitude of post‐activation potentiation performance benefits varied depending on the type of ELC protocol used.

Investigating the Impact of Catalyst Penetration into Gas Diffusion Layer on the Performance of High-Temperature Polymer Electrolyte Membrane Fuel Cells

The catalyst fabrication method, cell assembly, and operating conditions in polymer electrolyte membrane fuel cells (PEMFC) impact the catalyst penetration into the gas diffusion layer (GDL), alter its porous structure, and, consequently, the overall cell performance. This study investigates the effect of the catalyst layer (CL) penetration thickness, catalyst loading amount, and cell compression during assembly on species and current distributions, and overall cell performance. GDLs with large penetration thickness show a substantial resistance to reactant and proton transport, particularly at high current densities resulting in a drop in the cell performance. For zero, 50%, and 100% penetrations, the average current densities at an operating voltage of 0.4 V are 0.8329, 0.7920, and 0.71112 A cm−2, respectively. This indicates a performance loss of 5% and 15% for 50% and 100% penetrations in comparison to zero penetration. Higher catalyst loading results in greater penetration, negating the benefit of enhanced kinetics. Performance typically decreases by 3%–5% for 50% penetration and 12%–15% for 100% penetration when penetration levels increase for a certain Pt loading. An attempt is made to investigate the interplay between the effect of reactant and proton transport limitations on their distributions and cell performance. The combined effect of catalyst penetration and cell compression during the assembly has a crucial impact on cell performance with the starvation of reactants at high-density regions. The study highlights the necessity of optimizing the penetration thickness, catalyst loading, and cell assembly to achieve maximum cell performance.

End-Tidal Carbon Dioxide Measurement in Out-of-Hospital Cardiac Arrest as a Predictor of Return of Spontaneous Circulation: A Literature Review.

One of the leading causes of morbidity and mortality worldwide is out-of-hospital cardiac arrest. Early defibrillation and high-quality cardiopulmonary resuscitation (CPR) have improved survival. The main goal of CPR is to achieve return of spontaneous circulation (ROSC), which is assessed by looking for a pulse, analyzing the heart rhythm, and assessing carbon dioxide levels. The use of cartography during CPR to confirm the correct position of the endotracheal tube during intubation or to assess the effectiveness of chest compressions has increased significantly in the last years. The aim of this review was to identify correlations between end-tidal carbon dioxide levels and the likelihood of ROSC in patients with out-of-hospital cardiac arrest. A literature search was performed in MEDLINE (via Pubmed), Scopus, Web of Science, and Google Scholar databases from September to November 2022. Keywords combined with the Boolean operators (AND/OR) were used in both free text and Medical Subject Headings. Studies on adult patients published between 01/01/2016 and 28/09/2022 were searched, with no geographical restrictions. At the end of the selection process, 14 studies were included that investigated capnography in out-of-hospital CPR and reported at least 1 outcome between end-tidal carbon dioxide and ROSC or survival. Capnography is an advantageous tool due to its noninvasive characteristics, ease of use, and immediacy of data. In out-of-hospital cardiac arrest, the use of the end-tidal carbon dioxide appears to be an appropriate complementary tool to support clinical decisions, such as correct positioning of the endotracheal tube, optimizing ventilation in CPR, and as a predictor of ROSC.

Improving the effectiveness of CPR during interventional procedures.

The number of interventional procedures, such as transcatheter aortic valve replacements or thoracic endovascular aortic repairs, is on the rise. Intraprocedural cardiac arrest is a rare occurrence during high-risk procedures. Modern hybrid-operating tables may adversely affect chest compression quality due to their flexibility. To investigate this relationship, we analyzed the blood pressure generated during chest compressions at different degrees of table extension and assessed the effect of an additional stabilization bar to secure the table. A CPR manikin was connected to online blood pressure monitoring on a hybrid operating table. Chest compressions were administered using a mechanical device (at 100bpm and 80bpm). Hemodynamic effects were evaluated at various degrees of table extension (0%, 50%, 100% table extension) and with the addition of a stabilization bar. A greater degree of table extension was associated with lower diastolic blood pressure. The addition of a stabilization bar alleviated this drop in diastolic blood pressure and enabled the generation of higher mean arterial pressures at 50% and 100% table extension during chest compressions. The flexibility of a hybrid operating table adversely impacts the hemodynamic effect of chest compressions. This effect may be mitigated by using a stabilization bar. These results may be relevant for providing further recommendations for CPR guidelines in hybrid OR settings.

Influences of nozzle pressure ratio on flow characteristics of serpentine multi-stream supersonic nozzle

The serpentine multi-stream supersonic nozzle (SMSN) is adopted for the multi-stream exhausted system of the Adaptive Cycle Engine to enhance the stealth performance of next-generation fighter. In this paper, the effects of the nozzle pressure ratio (NPR) on the flow characteristics of the SMSN were studied using the numerical simulation method validated by experimental data. The serpentine configuration leads to the nonuniform pressure distribution. At the mixing position, the expansion and shock waves are generated due to the pressure difference. As the NPR increases, the flow separation and shock wave in the mixing section gradually weaken and disappear. The thrust coefficient rises first and then drops. Due to the flow separation under the design condition, the thrust coefficient is the largest at MPR=6 and TPR=2.272. As the MPR increases at TPR=1.893, the compression effect of the main flow is enhanced on the upper third flow. The thrust coefficient rises first and then drops, and reaches the maximum at MPR=6. As the TPR increases at MPR=5, the compression effect of the main flow is weakened on the upper third flow. The thrust coefficient rises first and then drops, and reaches the maximum at TPR=2.272.

The Effect of Red Ginger Compress on Joint Pain in the Elderly

Background : Elderly people will experience physical, social, and psychosocial changes. One of the complaints resulting from physical changes in the elderly is joint pain. Joint pain in the extremities experienced by the elderly is one of the most prevalent. Pain therapy using non-pharmacological techniques is an effective pain treatment and has minimal side effects for the elderly. One non-pharmacological technique that can be used to reduce pain in the elderly is using a red ginger compress. The content of red ginger can help reduce pain and act as an anti-inflammatory.
 Methods: Using a purposive sampling technique, 70 respondents were involved in this research. The group was divided into 2, namely 35 respondents as the control group and 35 respondents as the intervention group.
 Results : the results of the multivariate analysis test of a simple linear regression test showed that there was an effect of simultaneously administering red ginger compresses with a p-value of 0.000.
 Conclusion : Providing red ginger compress intervention has obtained significant results or has an effect on pain in the elderly, it is hoped that the elderly can take advantage of this intervention to reduce the symptoms and impact of musculoskeletal pain.

Sustainable supply chain operations driven by ‘remanufacturing + product sharing’: operation mode selection and decision optimisation

Consumers’ attention to sustainable production and consumption is promoting innovation in sustainable supply chain operations. We build an extended sustainable supply chain with remanufacturing (and/or) product sharing, and consider three operation modes: Sustainable supply chain operation with remanufacturing but No product Sharing mode (SNS), Sustainable supply chain operation with product sharing but No Remanufacturing mode (SNR), and Sustainable supply chain operation with both product Sharing and Remanufacturing mode (SSR). How does sustainable consumption (i.e. product sharing) affect sustainable production decisions and how to choose the optimal operation mode? Our findings: The SSR mode positively reinforces the sustainability-oriented market segmentation and can be globally optimal with an integrated value-added effect of ‘remanufacturing + product sharing’. From the perspective of total benefit optimisation, when the commission rate of a sharing platform and the proportion of service consumers are higher (lower), the transformation from the SNS mode to the SSR mode (from the SNR mode to the SSR mode) can be the best operational strategy. Maximising total benefits may have a compression effect on product sharing, which can be effectively adjusted by improving consumers’ perceived value of remanufactured products. This study provides guidance for selecting combination strategies for sustainable supply chains in the context of carbon emission reduction.

Computational modelling of compressible nonisothermal viscoelastic fluids

The prediction of compressible nonisothermal flows of viscoelastic fluids is important in many industrial processes. Until relatively recently, there was a lack of tractable thermodynamically consistent mathematical models for this class of flows. In this paper a stabilised finite element scheme is presented for the models developed by the authors Mackay and Phillips (2019) which incorporates compressibility and nonisothermal effects. Numerical results are presented for variants of a couple of benchmark problems: the lid driven cavity and the natural convection problems. The temporal discretisation is based on the Taylor–Galerkin method. A compressible version of the discrete elastic viscous split stress (DEVSS) formulation is used to stabilise the numerical scheme. The combined and separate influence of compressible, viscoelastic and thermal effects on the characteristics of these benchmark flows is studied for the first time.

Research On Pruning Methods for Mobilenet Convolutional Neural Network

This paper comprehensively reviews pruning methods for MobileNet convolutional neural networks. MobileNet is a lightweight convolutional neural network suitable for resource-constrained environments such as mobile devices.Various pruning methods can be applied to reduce the model's storage space and computational complexity, including channel pruning, kernel pruning, and weight pruning. Channel pruning removes unimportant channels to reduce redundant parameters and computations in the model, while kernel pruning reduces redundant calculations by pruning convolutional kernels. Weight pruning involves setting small-weighted elements to zero to remove unimportant weights. These pruning methods can be used individually or in combination. After pruning, fine-tuning is necessary to restore the model's performance. Factors such as pruning rate, pruning order, and pruning location need to be considered to achieve a balance between reducing model size and computational complexity while minimizing performance loss. Pruning methods based on MobileNet convolutional neural networks reduce the parameter count and computational complexity, improving model lightweightness and inference efficiency. These methods are of significant value in resource-constrained environments such as mobile devices. This review provides insights into pruning methods for MobileNet convolutional neural networks and their applications in lightweight and efficient model deployment. Further advancements such as automated pruning methods driven by reinforcement learning algorithms can enhance the pruning process to achieve optimal model compression effects. Future research should focus on adapting and optimizing these pruning methods for specific problem domains and achieving even higher compression ratios and computational speedups.

Intersubband optical gain spectra in compressively strained InGaAs/GaInP quantum well

In this paper, the theoretical analyses of the optical intersubband transitions in strained InGaAs/GaInP quantum well are investigated. A simplified method of the treatment of the compressive strain effects incorporation for the wavefunction and thus the intersubband dipole matrix is discussed. The effects of Gallium mole fraction, quantum well width and compressive strained on the band properties, intersubband transitions and optical absorption/gain spectra are shown to be pronounced. Thus this present investigation could become a good guild for tuning the optoelectronic properties of many quantum devices utilizing intersubband electronics in their various technological applications.

Experimental study on the explosion characteristics of ammonia-hydrogen-air mixtures

Ammonia-hydrogen blended fuel has drawn substantial attention as an environmentally friendly, carbon-free fuel because it effectively overcomes the inherent disadvantages of pure ammonia in combustion performance, such as a high ignition energy, slow combustion rate, and low combustion efficiency. While recent research on the combustion performance of hydrogen-ammonia blends has advanced, there remains a scarcity of studies addressing the explosion characteristics of these fuels. In this paper, a series of experiments conducted within a standard 20-L spherical combustion chamber to investigate the explosion characteristics of ammonia-hydrogen-air premixed gases under diverse conditions, spanning from low to high pressures (0.02–0.3 MPa) and from fuel-lean to fuel-rich scenarios (0.7–1.5), are discussed. The results reveal that the explosion characteristics are pronouncedly enhanced by hydrogen addition. The maximum explosion pressure (Pmax) and maximum pressure rise rate ((dP/dt)max) increase, while the explosion time (texp) decreases with increasing hydrogen concentration. Pmax and (dP/dt)max exhibit linear increases as the initial pressure rises and reach their peaks at an equivalence ratio of 1.1; texp displays nonmonotonic variations with increasing initial pressure and equivalence ratio. Hydrogen addition remarkably increases the hydrodynamic instability and thermal-diffusion instability of the reactive mixture, enhances the thermal-mass diffusion on the flame front, and promotes flame deformation and cellular structure formation, resulting in an improvement of the flame propagation and compression effect on the unburnt reactant before the flame. Research into the explosion characteristics provides valuable insights for the safe storage and transportation of ammonia-hydrogen blended fuels. These results indicate avenues for further enhancing the detonation characteristics and explosion performance of ammonia-hydrogen blended fuels.

The Effects of Signal to Noise Ratio, T60 , Wide-Dynamic Range Compression Speed, and Digital Noise Reduction in a Virtual Restaurant Setting.

Hearing aid processing in realistic listening environments is difficult to study effectively. Often the environment is unpredictable or unknown, such as in wearable aid trials with subjective report by the wearer. Some laboratory experiments create listening environments to exert tight experimental control, but those environments are often limited by physical space, a small number of sound sources, or room absorptive properties. Simulation techniques bridge this gap by providing greater experimental control over listening environments, effectively bringing aspects of the real-world into the laboratory. This project used simulation to study the effects of wide-dynamic range compression (WDRC) and digital noise reduction (DNR) on speech intelligibility in a reverberant environment with six spatialized competing talkers. The primary objective of this study was to determine the efficacy of WDRC and DNR in a complex listening environment using virtual auditory space techniques. Participants of greatest interest were listeners with hearing impairment. A group of listeners with clinically normal hearing was included to assess the effects of the simulation absent the complex effects of hearing loss. Virtual auditory space techniques were used to simulate a small restaurant listening environment with two different reverberation times (0.8 and 1.8 sec) in a range of signal to noise ratios (SNRs) (-8.5 to 11.5 dB SNR). Six spatialized competing talkers were included to further enhance realism. A hearing aid simulation was used to examine the degree to which speech intelligibility was affected by slow and fast WDRC in conjunction with the presence or absence of DNR. The WDRC and DNR settings were chosen to be reasonable estimates of hearing aids currently available to consumers. A WDRC × DNR × Hearing Status interaction was observed, such that DNR was beneficial for speech intelligibility when combined with fast WDRC speeds, but DNR was detrimental to speech intelligibility when WDRC speeds were slow. The pattern of the WDRC × DNR interaction was observed for both listener groups. Significant main effects of reverberation time and SNR were observed, indicating better performance with lower reverberation times and more positive SNR. DNR reduced low-amplitude noise before WDRC-amplified the low-intensity portions of the signal, negating one potential downside of fast WDRC and leading to an improvement in speech intelligibility in this simulation. These data suggest that, in some real-world environments that include both reverberation and noise, older listeners with hearing impairment may find speech to be more intelligible if DNR is activated when the hearing aid has fast compression time constants. Additional research is needed to determine the appropriate DNR strength and to confirm results in wearable hearing aids and a wider range of listening environments.

Ge-polymer bridge waveguide for mode-locked laser pulse generation.

A Ge-polymer hybrid waveguide is sandwiched between an indium phosphide (InP) reflective gain chip and a fiber Bragg grating (FBG) to construct a laser system. The hybrid waveguide serves as a bridge between the gain chip and the fiber with tailored mode-field matching at both facets. The 50-nm amorphous Ge (α-Ge) layer shows a nonlinear absorption effect at 1550 nm. The hybrid waveguide is further verified by a femtosecond laser transmission experiment to show the pulse width compression effect. Such waveguide is then integrated inside the laser cavity as a passive saturable absorber to modulate the longitudinal modes for a pulsed output. This polymer-bridged mode-locked laser adopts an InP gain chip for compact assembly and also a FBG with a flexible length to adjust the pulse repetition rate. The mode-locked laser output around the designed 50 MHz repetition rate is demonstrated. The pulse width is measured as 147 ps, and the signal-to-noise ratio is larger than 50 dB. This work introduces a "ternary" mode-locked laser system, taking advantage of discrete photonic components bridged by a polymer-based waveguide. It also proves the feasibility of applying α-Ge films as practical and low-cost saturable absorbers in photonic devices.

Thesis The Effect Of Warm Compresses On The Intensity Of Pain During The 1st Active Phase At Syekh Yusuf Gowa Hospital In 2020

Childbirth is a physiological event in every woman's development into motherhood. This event can cause trauma because of the pain experienced, hot compresses are one method to overcome pain. The purpose of this study was to determine the effect of warm compresses on the intensity of labor pain during the 1st active phase at Syekh Yusuf Gowa Hospital.This type of research uses quantitative research with a quasi-experimental research design. The research design is one group pretest and postest design. Sampling technique with purposive sampling. The sample size was 30 respondents. Analysis using statistical test Mc Nemart test. The results showed that before the warm compress there were 8 people (26.7%) who experienced mild pain and 22 people (73.3%) who experienced severe pain. After being given warm compresses there were 8 (26.7%) who changed mild pain to severe and there were 22 (73.3%) people who changed from severe pain to mild pain. Based on the Mc Nemart test.then obtained the value of ρ = 0.000 < 0.05, it can be concluded the effect of warm compresses on the intensity of labor pain when 1 phase is active. The conclusion of this study is that warm compresses are effective in reducing the intensity of labor pain during the active phase I at Syekh Yusuf Gowa Hospital. And it is hoped that health workers or midwives can apply warm water compresses to reduce pain in maternity mothers

To Compare the Effect of Ischemic Compression versus Dynamic Stretching Exercises on Pain in Subjects with Upper Trapezitis

Background: The most prevalent musculoskeletal ailment is trapezitis, which primarily affects the upper trapeziusmuscle due to overuse or strain.Purpose: The purpose of this study is to find out the effect of ischemic compression and dynamic stretchingexercises on pain in subjects with upper trapezitis.Materials and Methods: A total of 40 subjects were chosen from Neha Clinic and assigned to two groups, namelythe ischemic compression group along with Transcutaneous Electrical Nerve Stimulation (TENS) (n=20) and thedynamic stretching exercises group along with TENS (n=20), based on inclusion and exclusion criteria. Visualanalog scale (VAS) and cervical range of motion (CROM) were used as outcome measures. The entire process wasperformed from November 2022 to April 2023.Result: The mean value of ischemic compression at the post-test was found to be higher than the mean value ofdynamic stretching exercises, with a p-value of less than 0.0001Conclusion: The findings of this study suggest that ischemic compression is more effective than dynamic stretchingexercises in reducing pain associated with upper trapezitis.

Examining the Effects of Compression on Deep Learning Remote Photoplethysmography

Examining the Effects of Compression on Deep Learning Remote Photoplethysmography

Effect of external prestressing on the special shear lag behavior of precast box girder bridges

The shear lag behavior exhibited by precast segmental box girders (PSBGs) under concentrated external prestressing differs significantly from that observed in box girders subjected to vertical loads. To study the special shear lag behavior of PSBGs under external prestressing, a theoretical analytical method was developed based on the classical energy variational principle. In this analysis, the effect of external prestressing was decomposed into axial compression and bending effects through the equivalent load method. For each of these effects, appropriate longitudinal warping displacement modes were assumed, and the total energy functional expressions of the system under these two effects were further established. The governing differential equations for the two effects were derived using the principle of energy variation. Analytical solutions for the normal stress of the beam section under axial compression and bending effects were deduced, and corresponding boundary conditions were obtained. Subsequently, the normal stress of the section under the two effects was superimposed to obtain the comprehensive normal stress distribution curve of the beam section under external prestressing. The reliability of the theoretical analysis method was validated through a comparison of the theoretical analysis results with experimental and numerical analysis results.

Implementasi Kompresi File MP3 dengan Menerapkan Algoritma Levenstein

MP3 is an audio format that is often used because the data stored in MP3 format resembles the actual data when recorded.Storage space requirements will also rise if you keep a large number of MP3 files. Because of this, MP3 files must be compressed in order to prevent the storage space from filling up too quickly. This is because the compressed data will be lower in size. The Lossless compression method can be used to compress audio. The author uses the Levenstein Algorithm to implement audio compression in MP3 format. Levenstein's algorithm compresses data without any loss. When a file is compressed using lossless compression, the resulting file has the exact same size as the original file upon decompression. The author will be able to assess the effectiveness of MP3 file compression by using the Levenstein Algorithm to compress MP3 files. This will allow for faster transmission times and less data storage space consumption because the compressed MP3 file will shrink from its initial large size. After compression, the MP3 file's size—which was originally 128 bits—was reduced to 104 bits, yielding an 81.25% compression ratio. The purpose of this computation is to determine whether the compressed files are similar enough to be either decompressed or restored to their original size.