Valve System Research Articles

Cryopanel and fast closing valve system for ISOL beam operation

We designed a cryopanel system based on Molflow+ simulation and constructed for installation in a beam line of 70 MeV H- cyclotron to adsorb back streaming radioactive molecules from ISOL target. Since the target assembly is not hermetically sealed, a target leak can occur especially during high-power beam operation. The cryopanel surrounds the beam path to enhance adsorption efficiency and can be kept at temperature as low as 10 K. A beam test carried out at a current of ∼1 µA showed the panel temperature is not affected by beam pass. The vacuum in the panel region improves to better than 1 × 10-7 mbar so residual gas spectrum has a low background in detection of target leak. As part of the safety system against target damage, a fast closing valve is installed. These safety systems have been tested as essential components for radiation protection in ISOL operation.

Life-cycle integrity design method considering load robustness of offshore oil and gas equipment: SCSSV as a case study

Components that are vulnerable to the external environment and harsh working conditions easily fail during their life cycle under variable loads of offshore oil and gas equipment. The reliability of the system in the life cycle is reduced, various risks are increased, and substantial maintenance costs are generated. However, the current reliability-based design optimization method has difficulty meeting the situation that the life cycle is taken as the time dimension of design considering reliability, risk, and maintenance. To solve the problem, a life cycle integrity design optimization method considering robustness is proposed. A simplified integrity model is established through random load sampling and global sensitivity analysis. A multiobjective particle swam hierarchical optimization algorithm is proposed, in which hierarchical optimization order is determined by the priority of objectives, and the optimization design with structural integrity as the optimization objective is completed. The method is applied in the design of pressure pipeline of all-electric surface-controlled subsurface safety valve system.

Optimal oversizing in transcatheter aortic valve replacement with the self-expanding Evolut valve system.

Valve oversizing has been associated with reduced paravalvular leaks (PVL) and valve migration risk. However, no optimal cut-off oversizing value has been defined for the Evolut system (Medtronic). The aim of this study was to assess the relationship between the degree of oversizing and moderate-to-severe PVL and determine the optimal oversizing cut-off value. We conducted a multicenter study that included 740 consecutive patients with multidetector computed tomography (CT) data. Valve size was selected according to manufacturer recommendations, with oversizing ranging from 10% to 30%. The primary endpoint was moderate-to-severe PVL. The median age was 84 years (79-87 years), with 58.4% women, and a median EuroSCORE II of 4.1% (2.4-7.3%). Moderate-to-severe PVL was observed in 7.0% of the patients. An inverse relationship was found between oversizing and both PVL (11.3%, 8.6%, 5.4%, and 2.7% for quartiles Q1 to Q4; P = .007) and the need for post-dilation (P = .016). The multivariable analysis showed an association between oversizing and PVL (OR: 0.915 for each 1%-increase, P = .002). The optimal oversizing cut-off value to predict PVL was 20%, and PVL was significantly higher in patients with oversizing less than 20% (10.5% vs.4.2%, P less than .001). There were no differences in major clinical events according to the degree of oversizing, and a higher oversizing did not translate into an increased risk of permanent pacemaker (18.4% vs18.3%, P = .976). In TAVR with the Evolut valve, a higher oversizing was associated with lower rates of moderate-to-severe PVL and a lower need for post-dilation, with no negative impact on procedural and early clinical outcomes. A 20% oversizing threshold could be suggested to reduce PVLs. Further prospective studies are warranted to validate optimal oversizing for this valve system.

Clinical outcomes of the Myval transcatheter heart valve system in patients with severe aortic valve stenosis: a two-year follow-up observational study.

Limited data exist on long-term follow-up of severe aortic stenosis (SAS) patients who have undergone transcatheter aortic valve implantation (TAVI) with a new generation, balloon expandable Myval transcatheter heart valve (THV). Thus, we sought to investigate the performance and 2-year clinical outcome of the Myval THV system based on Valve Academic Research Consortium-3 (VARC-3) criteria. A multi-centre, registry-based, observational study was conducted, which included 207 consecutive degenerative SAS patients, from Turkey (n = 128), Italy (n = 58), and Greece (n = 21) (mean [standard deviation] 81 (7) years, 94 [45%] men; 73% NYHA III or IV; EuroSCORE II 5.2% [2.4%]); all patients underwent TAVI with Myval. Patients were followed up at 1 year and 2 years after implantation. Clinical and procedural outcomes were defined according to VARC-3 criteria. Technical success was observed in 204 (99%), device success was observed in 189 (91%), early safety was observed in 161 (78%), and clinical efficacy was observed in 163 (79%) patients. The 30-day death rate was 7.7%; of these, 3.4% were due to cardiovascular reasons. All-cause and cardiovascular mortality rates were 9.7% and 4.3% at 1-year follow-up, and 17.4% and 9.7% at 2-year follow-up, respectively. Incidence of ≥ moderate paravalvular leak (PVL) at 30 days, 1 year and 2 years of follow-up were 3.4%, 4.3% and 4.8%. A total of 11.1% of patients required a permanent pacemaker implantation (PPI) at 30 days after implantation, while the cumulative rate of PPI at 2 years was 12.1%. In this cohort of patients with SAS, the Myval was found to be safe and effective in up to 2 years of follow-up.

Preliminary Analysis and Optimization via CFD of a Liquid Hydrogen Pressure Regulating Piston Valve

Due to their high reliability and precision, piston valves are frequently used for pressure regulating applications. Particularly in the aerospace industry, where cryogenic fluids such as liquid hydrogen are frequently used, the design and operation of piston valves become crucial. The current state of advancement of this technology in the cryogenic field is still in its early stages, owing to the difficulties in designing such complex systems in harsh environments. This justifies the need for further in-depth studies and analysis using CFDs tools and predictive models. In order to ensure an optimal and efficient use of a piston pressure regulating valve in cryogenic environment, it is necessary to understand the strengths and limitations of this technology in an extreme thermal and mechanical condition. The presented work concentrates therefore on a preliminary analysis and optimization of a piston valve operating in liquid hydrogen flow field, for pressure regulating applications. Particular focus will be dedicated to the overall dynamics of the main body of the piston, in terms of robustness and controllability of the desired response of the system. The dynamics of the piston within an extremely low-viscous flow, as well as the thermodynamic and fluid dynamic aspects of the valve system, will be discussed. Simulations of the flow field will be performed through CFD tool, crossing the results with the dynamics of the simulated system response through and implemented Simulink model. The obtained results will be then critically analysed in order to suggest possible optimization of the valve in the locations where the system is most affected from a thermal and mechanical standpoint.

Long-term bio-functional performance of a novel, self-positioning balloon expandable transcatheter biological aortic valve system in the ovine aortic banding model.

The aim of the study was to evaluate bio-functionality of a novel, proprietary balloon-expandable biological transcatheter aortic valve implantation (TAVI) system (InFlow, CardValve Consortium, Poland) in an ovine model of aortic banding. Surgical ascending aorta banding was created in 21 sheep. Two weeks later, 18 biological valves were implanted within the model using 15-16 F InFlow TAVI systems and carotid cut-down approach. Follow-up transthoracic echocardiography was performed at 30, 90, and 180-day. At designated time, animals were euthanized and valves harvested for analysis. All sheep survived the banding procedure. There were 4 (22%) procedure related deaths within a 7-day period. During the observation an additional 2 sheep died. In one, the valve dislocated after the procedure - the animal was excluded. Two animals completed 30-day follow up, five 90-day follow-up and four terminal follow-up of 180 days. Valves examined via transesophageal echocardiography showed proper hemodynamic parameters without evidence of structural valve deterioration. The maximum and average flow gradients at 180 days were 31.4 (23.3-37.7) and 17.5 (13.1-20.2) mmHg, respectively. There was one case of moderate insufficiency and no case of perivalvular leaks. By histopathology, there were no inflammation, thrombosis, nor calcifications in any tested valves at long-term follow-up. Neointimal coverage of stent struts increased with time from basal part in "early" groups to nearly 3/4 of stent length in the 180-day group. The pannus tissue showed maturation that increased with time with no stenotic "collar" visible in orthotopically implanted valves. The study showed good hemodynamic performance, durability and biocompatibility of the novel biological THV.

17 years of experience with shunt systems in normal pressure hydrocephalus - From differential pressure to gravitational valves

ObjectiveComplication rate of shunting for normal pressure hydrocephalus (NPH) has significantly improved over the last decades. Especially the use of overdrainage protection has reduced the incidence of subdural hematoma and collections. However, gravitational valves were associated with other complications of shunt dysfunction. We present our 17 years of experience with patients with normal pressure hydrocephalus who changed from a differential pressure valve to a gravitational valve system. MethodsWe retrospectively identified all patients with the diagnosis of normal pressure hydrocephalus, in whom primary shunt implantation was performed between 2004 and 2020. Shunt implantation was performed as per our internal standard. Review of imaging, charts and patient reports was performed. ResultsIn total, 409 patients were included in the analysis. Mean age was 73.0 ± 7.1years. Between 2004 and 2010, predominantly Hakim valves (n = 100, 24.4%) were implanted, whilst from 2009 until 2020, proGAV valves (n = 296, 72.4%) were used. Mean follow-up was 8.9 ± 4.5 years. Initial subjective improvement of symptoms was reported in 69.9%, whilst this number decreased at the last follow-up to 29.8%. No significant differences were observed between the valves in the frequency of surgery for subdural hematoma. Shunt assistant implantation was performed in 17% of patients with Hakim valve, in 9.5% of patients with proGAV, a shunt assistant was added. Shunt obstruction was significantly higher in proGAV valves (p < 0.001). ConclusionsOur findings confirm the observation of frequent overdrainage in shunts without anti-siphon/gravitational component. Gravitational valves on the other hand may be associated with more obstruction.

Toward Translational Impact of Low-Glucose Strategies on Red Blood Cell Storage Optimization.

Transfusion of stored red blood cells (RBCs) to patients is a critical component of human healthcare. Following purification from whole blood, RBCs are stored in one of many media known as additive solutions for up to 42 days. However, during the storage period, the RBCs undergo adverse chemical and physical changes that are often collectively known as the RBC storage lesion. Storage of RBCs in additive solutions modified to contain physiological levels of glucose, as opposed to hyperglycemic levels currently used in most cases, reduces certain markers of the storage lesion, although intermittent doses of glucose are required to maintain normoglycemic conditions. Here, we describe an electrically actuated valving system to dispense small volumes of glucose into 100 mL PVC storage bags containing packed RBCs from human donors. The RBCs were stored in a conventional additive solution (AS-1) or a normoglycemic version of AS-1 (AS-1N) and common markers of stored RBC health were measured at multiple time points throughout storage. The automated feeding device delivered precise and predictable volumes of concentrated glucose to maintain physiological glucose levels for up to 37 days. Hemolysis, lactate accumulation, and pH values of RBCs stored in AS-1N were statistically equivalent to values measured in AS-1, while significant reductions in osmotic fragility and intracellular sorbitol levels were measured in AS-1N. The reduction of osmotic fragility and oxidative stress markers in a closed system may lead to improved transfusion outcomes for an important procedure affecting millions of people each year.

Transcatheter bicaval valve system for the treatment of severe isolated tricuspid regurgitation. Features from a single-Centre experience

BackgroundThe isolated tricuspid valve (TR) has evolved into an entity in its own right. In contrast to TR treatment in left valve surgery, the benefit of surgery for isolated TR remains controversial. In this context, transcatheter valve interventions (TTVI) are becoming increasingly important. In this report, we present our experience with TricValve in a single center. MethodsFrom March 2022 to September 2023, 13 patients with at least severe isolated TR were scheduled for TricValve implantation. The mean age was 81 years (77–87), 5 were female and 8 were male. All patients were older than 70 years and had at least severe TR, hepatic or peripheral congestion and high surgical risk. ResultsNo procedure failure or device embolization was recorded. One case died in hospital 6 days after implantation and 1 case died after 124 days from irreversible renal and hepatic failure. The survival rate was 80.2% ± 12.8; the proportion of patients in NYHA class I increased significantly to 45% at follow-up. Among the 11 survivors, the median NT -proBNP decreased from 2873 to 148 pg/mL at follow-up (p = 0.003). In addition, a significant reduction in furosemide dosage from 125 mg to 50 mg at follow-up was observed over time. Finally, TR grade improved significantly along with RV size. ConclusionsThis procedure appears to be safe and effective in carefully selected patients. Given the extreme simplicity of the procedure, the TricValve will increasingly represent one of the most viable treatment options for this patient group in the future.

Efficacy and safety of the Spiration Valve System™ for the treatment of severe emphysema in patients with Alpha-1 antitrypsin deficiency (EMPROVE)

ObjectivesAlpha-1 antitrypsin deficiency (AATD) is a hereditary condition associated with emphysema. This study analyzed the efficacy and safety of Spiration Valve System TM (SVS) among AATD patients with severe emphysema. MethodsThis multicenter prospective study included 20 patients demonstrating AATD as assessed by quantitative levels of AAT and genotype containing two ZZ alleles. Most diseased lobe based on high resolution computed tomography was selected for treatment with endobronchial SVS. The change from baseline in forced expiratory volume in 1 s (FEV1) at 6 months (Primary outcome) and at 12 months, quality-of-life (QoL) measured by St. George's Respiratory Questionnaire (SGRQ) as health status, dyspnea scale measured by mMRC, Chronic obstructive pulmonary disease (COPD) Assessment Test (CAT), 36-item Short Form Health Survey (SF-36) physical component summary (PCS) and safety were assessed. ResultsLung function (FEV1) significantly improved at 6 months (P = 0.02); but did not reach statistical significance at 12 months (P = 0.22). Significant improvement was observed in dyspnea (at all time points), QoL measures (3, 6, and 12 months), CAT score and PCS of SF-36 (1, 3 and 6 months). Response rates based on minimal clinically important difference reached 50–80% for all variables. Overall, 4.4 valves/patient were used to isolate the target lobe, with a mean procedure time of 20.3 min. Serious adverse events included COPD exacerbations (5%), pneumonia (10%), pneumothorax (15%) and death (5%), occurring within first three months. ConclusionSVS endobronchial valve treatment showed improvement in lung function, dyspnea, and QoL in AATD patients with severe emphysema.

(045) Comparing Bacterial Presence with the Usage of 0.05% Chlorhexidine Gluconate (CHG) Lavage During Urologic Prosthesis Revision Surgery: Update on Results

Abstract Introduction An Inflatable Penile Prosthesis (IPP) is third line surgical therapy for refractory ED. An IPP uses a fluid-filled reservoir with a pump and valve system to activate inflation and deflation. Although penile implants achieve the highest success rates in ED treatment, the possible presence of bacteria on the device itself or bacteria exposure accumulated during the surgery increases the risk of progression into biofilm or infection. Biofilm complicates the bacteria eradication effort and can ultimately jeopardize the implant. Often, the only way to treat the post-op infection is with implant removal. Currently, many preventative measures, such as different perioperative irrigations, are being studied to reduce the number of penile implant infections. Research has shown that irrigation at the time of both infectious and noninfectious surgery lowers subsequent infection rates. Different solutions like saline, antibiotic, betadine, and hydrogen peroxide solutions have been considered. Recently, orthopedic literature has shown that 0.05% Chlorhexidine Gluconate (CHG) lavage has effectively reduced biofilm in artificial joint procedures. Objective The purpose of this study is to determine the effectiveness of CHG lavage on bacterial presence in IPP implant spaces. We hypothesize that CHG will lower bacterial presence after washing out implant spaces at time of replacement for infections and mechanical failure. Methods We aimed to investigate a series of patients who underwent revision IPP surgery while utilizing FDA-approved CHG lavage for irrigation and compared the bacterial presence before and after CHG washout. Additionally, Next Generation Sequencing (NGS), a DNA sequencing technology, was used to further identify the pathogens involved. Results Between 2021 to 2023, 48 patients underwent IPP revision surgery for either infectious or noninfectious reasons. During the operation, a section of the capsule tissue surrounding the implanted IPP pump was first taken and sent for cultures. NGS studies were also sent out. After the implant removal, all implant spaces were irrigated and washed out with CHG (two 450-mL bottles). A second tissue culture was then obtained post washout. Of the 48 patients, there were 4 positive bacterial cultures before washout and 13 positive NGS results. Results of the post CHG washout cultures were all negative. Conclusions It appears that irrigation with 0.05% Chlorhexidine Gluconate solution is an effective antiseptic that can decrease bacterial presence, and hopefully reduce IPP infections. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Microgen Dx, Irrisept.

Experimental study on cavitation inhibition in a butterfly valve with different plate shapes

A valve is a kind of mechanical device used to control the flow of fluid in pipelines or systems, which has a wide range of uses in various industrial, commercial, and household applications. When the fluid passes through the valve, cavitation often occurs in the valve, resulting in the valve not working properly and even damaging the valve and related systems. In this paper, experimental visualization was used to investigate cavitation evolution through a butterfly valve with different plate shapes under different pressure conditions. The results show that with the increase in the curvature of both sides of the butterfly plate and the increase in the total pressure condition, the cavitation type inside the butterfly valve will change from non-attached cavitation to attached cavitation. In addition, the maximum length and thickness of the attached cavitation bubbles gradually increase as well. However, when the shape of both ends of the butterfly plate is triangular, the adhesion ability to cavitation bubbles is greatly reduced. As the curvature increases, the frequency of the shedding of cavitation bubble gradually decreases, the volume of cavitation bubble increases, and the shedding of the cavitation bubble caused by the shock wave is more obvious. When the shape of both sides of the butterfly plate is triangular, the position where the bubble collapses is closer to the front end of the butterfly plate, and the shock wave generated by the bubble collapse will lead to the collapse of the attached cavitation bubble.

Mean compression ratio of a self-expandable valve is associated with the need for pacemaker implantation after transcatheter aortic valve replacement

BackgroundThe risk and timing of permanent pacemaker implantation (PPMI) after transcatheter aortic valve replacement (TAVR) is still hard to predict. We aimed to analyze the relationship between the compression ratio of a self-expandable valve (SEV) and the need for PPMI after TAVR.MethodsA total of 106 patients who were implanted with the VitaFlow transcatheter aortic valve system and for whom complete imaging information was available were included in this retrospective cohort study. Eight lines perpendicular to the long axis of the SEV were drawn (the top and bottom of the SEV and the intersection of each row of wires) for measurement purposes. The compression ratio was calculated as 1 − (in vivo meridian/in vitro meridian) and compared between patients undergoing and those not undergoing PPMI after adjusting for implantation depth. Multivariable logistic regression and Cox proportional hazards models were used to assess factors associated with the risk and timing of the need for PPMI.ResultsFifteen (14.2%) patients underwent PPMI after TAVR. Patients with a higher mean compression ratio (20%, odds ratio [OR] = 214.82; p < 0.001) and prior right bundle branch block (OR = 51.77; p = 0.015) had a higher risk of the need for PPMI after TAVR. These two factors were also associated with the timing of PPMI, according to the Cox proportional hazards model.ConclusionsThe compression ratio of the SEV was positively associated with the risk of PPMI after TAVR, and the association was most significant in the annular and supravalvular planes. The compression ratio may also affect the time to PPMI.

Extended state observer design for uncertainty estimation in electronic throttle valve system

AbstractThe Electronic Throttle Valve (ETV) is the core part of automotive engines which are recently used in control-by-wire cars. The estimation of its states and uncertainty is instructive for control applications. This study presents the design of Extended State Observer (ESO) for estimating the states and uncertainties of Electronic Throttle Valve (ETV). Two versions of ESOs have been proposed for estimation: Linear ESO (LESO) and Nonlinear ESO (NESO). The model of ETV is firstly developed and extended in state variable form such that the extended state stands for the uncertainty in system parameters. The design of both structures of ESOs are developed and a comparison study has been conducted to show the effectiveness of the proposed observers. Numerical simulation has been conducted to assess the performance of observers in estimating the states and uncertainties of ETV. The simulated results showed that both full order and reduced order models of ETV have the same transient characteristics. Moreover, the effectiveness of two versions of observers has been examined based on Root Mean Square of Error (RMSE) indicator. The results showed that the NESO has less estimation errors for both states and uncertainties than LESO.

Single-Center Experience with the Balloon-Expandable Myval Transcatheter Aortic Valve System in Patients with Bicuspid Anatomy: Procedural and 30-Day Follow-Up.

Aims: To report our single-center data regarding the initial 52 consecutive patients with a bicuspid aortic valve who underwent a Transcatheter Aortic Valve Implantation (TAVI) procedure using the new balloon-expandable MYVAL system. The focus is on reporting procedural details and outcomes over the 30-day postoperative period. Methods: From December 2019 to July 2023, 52 consecutive patients underwent a TAVI procedure with bicuspid anatomy. All patients had moderate to-high surgical risk or were unsuitable for surgical aortic valve replacement based on the Heart Team's decision. Outcomes were analyzed according to the VARC-2 criteria. The results of bicuspid patients were compared to patients with tricuspid anatomy in the overall study group, and further analysis involved a comparison between 52 pairs after propensity score matching. The device performance was evaluated using transthoracic echocardiography. Data collection was allowed by the Local Ethical Committee. Results: The mean age was 71 ± 7.1 years, and 65.4% were male. The mean Euroscore II and STS score were 3.3 ± 3.2 and 5.2 ± 3.3, respectively. Baseline characteristics and echocardiographic parameters were well balanced even in the unmatched comparison. Procedures were significantly longer in the bicuspid group and resulted in a significantly higher ARI index. All relevant anatomic dimensions based on the CT scans were significantly higher in bicuspid anatomy, including a higher implantation angulation, a higher rate of horizontal aorta and a higher proportion of patients with aortopathy. In the unmatched bicuspid vs. tricuspid comparison, postprocedural outcomes were as follows: in-hospital mortality 0% vs. 1.4% (p = 0.394), device success 100% vs. 99.1% (p = 0.487), TIA 1.9% vs. 0% (p = 0.041), stroke 1.9% vs. 0.9% (p = 0.537), major vascular complication 3.8% vs. 2.3% (p = 0.530), permanent pacemaker implantation 34% vs. 30.4% (p = 0.429), and cardiac tamponade 0% vs. 0.5% (p = 0.624). In the propensity-matched bicuspid vs. tricuspid comparison, postprocedural outcomes were as follows: in-hospital mortality 0% vs. 0%, device success 100% vs. 100%, TIA 1.9% vs. 0% (p = 0.315), stroke 1.9% vs. 0.9% (p = 0.315), major vascular complication 3.8% vs. 0% (p = 0.475), permanent pacemaker implantation 34% vs. 24% (p = 0.274), and cardiac tamponade 0% vs. 0%. There was no annular rupture nor need for second valve or severe aortic regurgitation in both the unmatched and matched comparison. The peak and mean aortic gradients did not differ at discharge and at 30-day follow-up between the two groups regardless of whether the comparison was unmatched or matched. There were no paravalvular leakages (moderate or above) in the bicuspid patients. Intermediate and extra sizes of the Myval THV system used a significantly higher proportion in bicuspid anatomy with a significantly higher oversize percentage in tricuspid anatomy. Conclusions: The TAVI procedure using the Myval THV system in patients with significant aortic stenosis and bicuspid aortic valve anatomy is safe and effective. Hemodynamic parameters do not differ between tricuspid and bicuspid patients. However, the permanent pacemaker implantation rate is higher than expected; its relevance on long-term survival is controversial.

Transient-based multiple branch detection in reservoir pipeline valve systems

Efficient management of pipeline assets is crucial for a reliable urban water supply. Unknown side branches in pipeline systems can hinder the prediction of hydraulic transients, owing to unexpected pressure responses. Herein, we developed a method for detecting multiple side branches in a simple reservoir pipeline valve system. A polynomial-based transient characterization scheme was proposed to address nonlinear valve manoeuvres, which substantially improved the transient simulations over conventional orifice-based approximations. A procedure for pressure signal manipulation via the superimposition of pressure signals with and without branches and isolation of the interference between various branched elements, which distorted the pressure response of multiple branches, was introduced. The model performance was evaluated by comparing the interference-isolated signals obtained from the conventional method, proposed scheme, and experimental datasets. Effective phase matching of the pressure responses obtained via the proposed scheme and experimental data indicated the potential of the former for detecting multiple branches.

Fluid Viscous Dampers for seismic protection of bridges: a State of the Art

Fluid Viscous Dampers (FVDs) are particular devices that dissipate energy through the lamination of a viscous fluid forced by a piston to pass through an orifice or a valving system. These devices are capable of dissipating large amounts of energy without significantly altering the inherent stiffness of the structure, with a response that strictly depends on the velocity. Therefore, FVDs have been largely employed in bridges since the mid-1990s with the aim of accommodating service slow motions (like thermal motions) and guaranteeing protection from seismic and wind loads that occur at significant speeds. FVDs are suitable both for retrofitting existing vulnerable bridges and for designing new ones. The aim of this paper is to present the evolution of FVDs for the seismic protection of bridges, moving from the first application with passive FVDs to modern devices such as semi-active FVDs, electrorheological, magnetorheological, variable stiffness, and variable damping dampers. Due to the increasingly large number of available devices, this work does not attempt to present a complete state-of-the-art on the subject but focuses on discussing the main milestones as well as the most relevant drawbacks. Devices selected for discussion are shown from a historical perspective and, according to the authors, represent pioneer original steps in the field of seismic protection of bridges with dampers.

Monitoring and Fault Diagnosis of Breathing Valves in Atmospheric Storage Tank under Fuzzy PID

The atmospheric storage tank breathing valve relies too much on manual experience and simple monitoring methods in monitoring and fault diagnosis, and cannot provide high-precision fault diagnosis and prediction. Therefore, this article introduces a monitoring and fault diagnosis system for atmospheric storage tank breathing valves based on Fuzzy PID (Proportional-Integrated-Derivative). The research aims to design the atmospheric storage tank breathing valve system into three modules. The monitoring module uses sensors for data collection, while the early warning module classifies the data based on the monitoring module to find the optimal classification boundary and achieve abnormal state recognition. The fault diagnosis module uses the fuzzy PID algorithm to thoroughly inspect and evaluate the abnormal conditions detected in the atmospheric storage tank, and finally evaluates the monitoring and fault diagnosis of the atmospheric storage tank breathing valve before and after improvement. The results showed that the diagnostic accuracy improved by using fuzzy PID was 35.2% higher than before. In summary, the diagnostic method proposed in this paper is superior to the traditional method and improves the reliability and performance of the system.

Control system for suction valves within gas compressors skids located in potentially explosive zones

The paper presents the implementation of a feedback loop controller for the suction valves used within the gas compressors skids manufactured by Romanian Research and Development Institute for Gas Turbines COMOTI. These compressors are installed at beneficiaries, in potentially explosive environments (e.g., gas extraction and transportation applications). The proposed solution addresses the problems observed due to the high suction pressures of screw compressors, which may occur at start-up or during operation, leading to failed start-ups or emergency shutdowns. An automatic sequence implemented in the control software and displayed on the operating panel, could assist the operator during high suction pressures (above 1.2 bar). These pressure conditions normally lead to alarm limits and to performing an automatic shutdown sequence for protecting the compressor. The paper herein discusses the implementation of a start-up sequence in the programmable logic controller’s software, which can be applied without critical interventions on the compressor packages, only through minor control software modifications which can safely extend the inlet pressure range and the exploitation of the compressors. Thus, since no hardware modifications are required, we also ensure maintaining the ATEX certifications of equipment and assemblies.

A Comprehensive Evaluation of the NAVITOR Transcatheter Aortic Valve Replacement System.

Transcatheter aortic valve replacement (TAVR) has undergone significant advancements in the last two decades, expanding its indications and refining transcatheter heart valve (THV) and delivery system designs to improve procedural success and patient outcomes. This review focuses on the Navitor™ valve, a third-generation intra-annular Portico™ valve (Abbott Structural Heart, St Paul, MN, USA) designed to address TAVR complications, particularly paravalvular leak (PVL). We present an overview of the Navitor™ system, comparing it to the first-generation Portico™ THV in terms of THV design, key iterations and clinical outcomes. The Navitor™ THV introduces two key refinements-a protective outer sealing skirt and a more flexible delivery system. These enhancements have led to a significant reduction in 30 day PVL rates, from 6.3% with the first-generation Portico™ to 0% with the Navitor™ system. Additionally, the Navitor™ system exhibited lower rates of severe bleeding (27.3% versus 13.1%) and major vascular complications (5.8% versus 0.7%) compared with the first-generation Portico™. The Navitor™ valve represents a promising advancement in TAVR technology, with notable reductions in complications such as PVL, severe bleeding, and major vascular issues, compared with its predecessor. While further research is needed to assess long-term durability, these results underscore its potential benefits in enhancing patient outcomes and reducing complications. This review provides insights into the evolving landscape of TAVR technology and its quantifiable impact on patient care.