Excessive Rise Research Articles

Therapeutic potential inhibitor for dipeptidyl peptidase IV in diabetic type 2: in silico approaches.

Diabetes mellitus (DM)is a metabolic disease marked by an excessive rise in blood sugar (glucose) levels caused by a partial or total absence of insulin production, combined with alterations in the metabolism of proteins, lipids, and carbohydrates. The International Diabetes Federation estimates that 425 million individuals globally had diabetes in 2017 which will be 629 million by 2045. Several medications are used to treat DM, but they have limitations and side effects including weight gain, nausea, vomiting, and damage to blood vessels and kidneys. Therefore, it is essential to identify anti-diabetic drugs that have lessor no side effects. Hence, the current study employed in silico approaches to discover new DPP-IV inhibitors that might be associated with diabetes. Thirty-four (34) co-crystalized DPP-IV enzymes were found from the protein data bank and the co-crystal ligands were docked into the active-site 6B1E protein to find out the hit compounds. From the docking results, we found two hit compounds (5T4E and 4J3J) which were used to find out the analogs from the experimental drug database using the DrugRep software. According to the results, twenty (20) analogs were found from the experimental drug database with the similarity score of ≥ 0.790 and docked once again into the active site of the DPP-IV (PDB ID: 6B1E) enzyme. Interestingly, DB02226 showed the best binding affinity (-10.3kcal/mol) and prime MM/GBSA (-68.73kcal/mol) compared to the reference drug (co-crystal ligand; -7.4kcal/mol and -47.49kcal/mol, respectively). Additionally, DB02226 has shown excellent reactivity, efficacy, and structural stability in the binding region of target proteins in studies using MD simulation, MM/GBSA, DFT, and MESP analysis. These findings can be utilized to support further in vitro, in vivo, pre-clinical and clinical research rather than definitively confirming anti-diabetic effectiveness.

Circadian rhythm of blood pressure and its correlations with short-term variability

Background. Arterial hypertension (AH) is the main risk factor for cardiovascular (CV) and cerebrovascular diseases. To effectively prevent damage to target organs and reduce morbidity and mortality, adequate control of blood pressure (BP), including its variability (VAR), is important. The latter includes circadian, short-term, and long-term components, and VAR is best documented with out-of-office BP monitoring methods such as ambulatory BP monitoring (ABPM). The morning rise (MR) of BP is one of the components of variability, its disturbances are associated with an increased risk of stroke and CV events, regardless of the level of BP. Purpose – the aim of the study was to study the relationship between the morning rise in blood pressure and the short-term blood pressure variability in patients with arterial hypertension. Materials and Methods. The study included 169 patients with hypertension aged 43 to 78 years. Based on the results of ABPM, an assessment of the morning dynamics and short-term BP VAR were carried out. To assess the morning dynamics of blood pressure, the speed and amplitude of MR of systolic BP (SBP) and diastolic BP (DBP) were studied. SBP and DBP VAR were evaluated separately for day, night, and 24-hour periods using the SD, SDcorr, and ARV indices. Results. In this open, non-randomized, cross-sectional study of patients with hypertension, a direct relationship between BP VAR and its morning dynamics was revealed – the increase in VAR was associated with greater amplitude and speed of BP MR. The established correlations were closer for MR amplitude than for MR speed, which allows to draw a conclusion about different pathogenesis mechanisms of their disorders and requires further study of this phenomenon. An increase in VAR SBP was associated not only with changes in the morning dynamics of SBP, but also with changes in the morning dynamics of DBP, and vice versa Conclusions. ABPM should be an essential part of the management of hypertensive patients with an individualized approach to pharmacotherapy to achieve not only optimal 24-hour BP control, but also correction of elevated BP and excessive morning rise for the best cardiovascular and cerebrovascular protection.

Experimental investigation on treating dredged silt ground using vibratory probe compaction combined with well-point dewatering

This study improved the vibratory probe compaction (VPC) technique by combining it with well-point dewatering to address the challenges of treating newly dredged silt ground. Specific methods were presented to determine the operating frequency based on multi-channel analysis of surface waves (MASW) results, as well as the spacing between compaction points derived from vertical vibration velocity measurements. The effects of well-point dewatering were analyzed through field monitoring of groundwater level, pore water pressure, and ground settlement. A comparative evaluation of the reinforcement of the improved and conventional VPC techniques was conducted through in-situ tests. The results indicate that continuous dewatering suppresses the excessive rise of excess pore water pressure during compaction, effectively eliminating equipment tilting and settlement due to sandblasting water, and enhancing construction efficiency by over 40%. The average standard penetration blow count (N 63.5) increases from 4.3 to 11.4, the ground bearing capacity reaches 140.8 kPa and the average ground settlement is 42.5 cm. The cone resistance and sleeve resistance also exhibit higher values, and the risk of soil liquefaction is effectively eliminated. The experiments and practices provide some successful experiences for the wider application of this technique in similar newly reclamation grounds.

Optical engine investigation of two-injection strategies for energy-assisted compression-ignition combustion of low cetane number sustainable aviation fuels

A two-injection strategy was investigated for energy-assisted compression-ignition combustion using hot surface ignition of low-cetane number sustainable aviation fuels in an optically-accessible engine. In-cylinder pressure measurements and OH chemiluminescence imaging were employed to assess the combustion process. Three experimental studies were performed to understand and optimize the EACI combustion process: a single injection design-of-experiments (DoE), a two-injection injection DoE, and a modified two-injection dwell sweep. The fuel used for this investigation was a cetane number 35.5 binary blend of an alcohol-to-jet (ATJ) fuel with a cetane number of ~17 and F-24 (Jet-A with military additives) with a cetane number of 48.5. Results demonstrate a two-injection strategy can enable a complete and stable EACI combustion without excessive pressure rise rates for the right set of ignition assistant temperature and injection parameters. Parameters that assist in establishing this are higher ignition assistant temperatures (>1400 K), longer injection dwells (>1.5 ms), and lower injection pressures (near 600 bar). These parameters increase the extent of heat release from the first injection and influence the location of hot combusted gases. The first injection heat release is essential to enable rapid ignition of a majority of second injection fuel jets. This limits the amount of end-gas autoignition, reducing pressure rise rates and avoiding pressure oscillations. The ability of the first injection to positively influence the ignition process of the second injection is encouraging and provides guidance on the approach to operate with even lower cetane number renewable fuels.

Significant Improvement in Magnetorheological Performance by Controlling Micron Interspaces with High Permeability Submicron Particles.

The shear yield strength, sedimentation stability and zero-field viscosity of magnetorheological fluids (MRFs) are crucial for practical vibration damping applications, yet achieving a balanced combination of these performances remains challenging. Developing MRFs with excellent comprehensive performance is key to advancing smart vibration damping technologies further. Theoretically, incorporating a multiscale particle system and leveraging synergistic effects between their can somewhat enhance MRFs' performance. However, this approach often faces issues such as insignificant increases in shear yield strength and excessive rise in zero-field viscosity. In response, this study employs a DC arc plasma method to synthesize a high magnetic permeability, low coercivity submicron FeNi particles, and further develops a novel CIPs-FeNi bidisperse MRFs. The introduction of submicron FeNi particles not only significantly enhances the shear2019 yield strength of MRFs under low magnetic fields but also promotes improvements in sedimentation stability and redispersibility without excessively increasing viscosity. Comprehensive performance analysis is conducted to explore the optimal content ratio, and detailed mechanisms for the enhancement of performance are elucidated through analysis of parameters such as chain-like structure, magnetic flux density and friction coefficient. Most importantly, the superior comprehensive performance combined with straightforward fabrication methods significantly enhances the engineering applicability of the CIPs-FeNi bidisperse MRFs.

Excessive Blood Pressure Rise and Cardiovascular Remodeling in Marathon Runners.

Exercise-induced hypertension (EIH) is thought to be associated with increased cardiovascular (CV) risks. However, no previous studies have investigated the effects of EIH on CV systems in marathon runners without CV risk factors using both 24-hr ambulatory blood pressure (BP) monitoring and exercise stress echocardiography (ESE). This study firstly described differences in CV adaptations according to EIH assessed by both exams. Marathon runners between 35 and 64 years of age without CV risk factors were eligible. All the participants underwent both 24-hr ambulatory BP monitoring and ESE. EIH was defined as a maximal exercise systolic BP≥210 mmHg. The EIH group (n=19) had shorter training history and higher exercise intensity compared to the non-EIH group (n=23). The average systolic BP was higher in the EIH group than in the non-EIH group. Left cardiac chamber size and left ventricular mass (LVM) were also higher in the EIH group compared to the non-EIH group. Maximal BP during ESE was positively correlated with both parameters. Exaggerated BP response during exercise needs to be monitored for pre-emptive measurements before it results in progressive cardiovascular maladaptation.

Urbanization Impacts the Soaring Housing Price of Hangzhou During 2018-2022

This paper examines the reasons for the rapid increase in housing prices in Hangzhou between 2018 and 2022. As one of China's fast-growing cities, Hangzhou has experienced significant changes in its real estate market due to continued population growth and accelerated urbanization, especially driven by major events such as the G20 Summit and the Asian Games. Firstly, the improvement and expansion of the city's infrastructure, especially the development of Hangzhou's metro network, has increased the attractiveness and property values of specific areas. Second, the government's talent admission policies and the city's overall attractiveness led to a population surge, further pushing up housing demand. In addition, special events such as the G20 Summit and the Asian Games and the urban renewal programs they bring have stimulated housing prices to a certain extent. In response to these reasons, it is recommended that the government take multifaceted measures to control the excessive rise in housing prices, including strengthening the regulation of the real estate market, rationalizing the planning of urban development, and providing more affordable and rental housing. The Government has optimized its policies to meet the housing needs of different income groups so as to achieve long-term stability and healthy development of the real estate market.

Global hotspots of climate-related disasters

Climate change mitigation is crucial to prevent excessive temperature rise, a primary contributor to climate-related impacts. However, even if net zero emissions were achieved immediately, the carbon locked in the atmosphere will continue to impact ecosystems, people, settlements and infrastructure, as observed in the past several decades. Despite the urgent need to minimize climate change impacts, climate adaptation has not kept pace with escalating risks. Data on disaster occurrences and impacts can guide action to where it is most needed. We used data on climate-related disasters recorded between 2000 and 2020 in the Emergency Events Database (EM-DAT) to 1) discern disparities in climate-related disaster impacts across countries and continents, and 2) pinpoint administrative areas where people have been highly impacted from those types of disasters. During this period, over 4,600 occurrences of climate-related disasters were documented, directly impacting over 3.3 billion people. Highly developed countries experienced fewer impacts despite not having a lower number of climate-related events. African countries showed an increase in the number of people impacted through time, despite a decrease in the number of climate-related events. Areas in Central America and the Caribbean, Eastern North America, Eastern Africa and Madagascar, and Southern and Eastern China, India and Southeast Asia had the highest numbers of people impacted per km2. Identifying locations with disproportionally high numbers of impacted people can lead to action and policy shifts, from local to international levels. Some of the approaches to adapt to climate change impacts that can be cost-effective and readily available are those based on nature and the benefits that nature provides to people. Therefore, nature conservation, restoration and management could be important interventions to help people adapt to the impacts of climate change, especially in areas of low human development and where people have experienced high and very high climate impacts. In the policy sphere, synthesizing information on historical occurrences of climate-related disasters could guide efforts to address losses and damages and to promote climate justice.

A two-dimensional semi-analytic thermal model for global temperature distribution predicting and hot spot monitoring in interior permanent magnet synchronous motor

A two-dimensional semi-analytical thermal model (SATM) is presented, aiming to quickly and accurately achieve global temperature distribution predicting and hot spot monitoring for interior permanent magnet synchronous motor (IPMSM). Thereby, it provides a reliable analysis tool for thermal behavior evaluation and prevents undesired consequences induced by excessive temperature rise, which is of great worth and significance in promoting the flourishing of IPMSM. SATM combines the analytical method, lumped parameter thermal network, and finite element analysis to obtain an analytical solution for thermal behavior through mathematical derivation by considering the complicated configuration, heat source distribution, heat dissipation condition, and material thermal dependence. Through SATM, it is possible to observe the global temperature distribution as well as the location and size of hot spots in each element. The temperature distribution gradient on the static is more pronounced than that on the dynamic; secondly, the area with the most severe heating is mainly found on the winding; furthermore, the hot spot on the winding is mainly located a little bit inside the center. Moreover, the thermal behavior of IPMSM at rated load is investigated by numerical analysis and experiments. A comprehensive comparison with SATM is done. The computational deviations between SATM and numerical analysis regarding the hot spot, minimum, and average temperatures on each element are all within 4.06 %. However, SATM consumes only 20.92 % of the time and 68.29 % of the storage of the numerical analysis. The measured data also fully prove the reliability and validity of the comparison. It is certain that SATM can well break through the limitation of the existing non-numerical technique to quickly and accurately achieve global temperature distribution predicting and hot spot monitoring of IPMSM. It provides researchers and engineers engaged in thermal behavior evaluation with good analysis means, design guidance, and optimization direction.

Multi-scale recurrent transformer model for predicting KSTAR PF superconducting coil temperature

Superconducting coils play a critical role in a superconducting-based nuclear fusion device. As the temperature of superconducting magnets increases with a change in current, it is important to predict their temperature to prevent excessive temperature rise of coils and operate them efficiently. We present multi-scale recurrent transformer system, a deep learning model for forecasting the temperature of superconducting coils. Our system recurrently predicts future temperature data of the superconducting coil using the previous data obtained from a multi-scale Korea Superconducting Tokamak Advanced Research poloidal field coil dataset and latent data calculated from previous time step. We apply a multi-scale temperature downsampling approach in our model to effectively learn both the details and the overall structure of the temperature data. We demonstrate the effectiveness of our model through experiments and comparisons with existing models.

Optimal power flow of thermal-wind-solar power system using enhanced Kepler optimization algorithm: Case study of a large-scale practical power system

In the current century, electrical networks have witnessed great developments and continuous increases in the demand for fossil fuels based energy, leading to an excessive rise in the total production cost (TPC), as well as the pollutant (toxic) gases emitted by thermal plants. Under this circumstances, energy supply from different resources became necessary, such as renewable energy sources (RES) as an alternative solution. This latter, however, characterized with uncertainty nature in its operation principle, especially when operator system wants to define the optimal contribution of each resource in an effort to ensure economic and enhanced reliability of grid. This paper presents an Enhanced version of Kepler optimization algorithm (EKOA) to solve the problem of stochastic optimal power flow (SOPF) in a most efficient way incorporating wind power generators and solar photovoltaic with different objective functions, the stochastic nature of wind speed and solar is modeled using Weibull and lognormal probability density functions respectively. To prove the effectiveness of the proposed EKOA, various case studies were carried out on two test systems IEEE 30-bus system and Algerian power system 114-bus, obtained results were evaluated in comparison with those obtained using the original KOA and other methods published in the literatures. Thus, shows the effectiveness and superiority of the efficient EKOA over other optimizers to solve complex problem. The incorporation of RES resulted in a significant 2.39% decrease in production cost, showcasing EKOA’s efficiency with a $780/h, compared to KOA’s $781/h, for IEEE 30-bus system. For the DZA 114-bus system revealed even more substantial reductions, with EKOA achieving an impressive 12.6% reduction, and KOA following closely with a 12.4% decrease in production cost.

Distributed Voltage Control Strategies in a LV Distribution Network

As the amount of locally installed distributed generation is increasing rapidly, voltage quality problems begin to arise in the LV distribution network. Particularly the introduction of large amounts of distributed generation may cause an excessive voltage rise on a distribution feeder violating the voltage limitations. PV installations specifically are found to trip on days with high solar irradiance and low load. New standards for the connection of locally installed generators to the LV distribution grid will have to be developed in order to enable the large scale implementation of distributed generation in the LV distribution grid, and to avoid unwanted tripping of the locally installed generation units. In this paper, different voltage control mechanisms are discussed and compared in terms of grid losses and profitability of the installed generation for a typical Belgian distribution network topology.

A novel microchannel-twisted pinfin hybrid heat sink for hotspot mitigation

Thermal hotspots cause excessive localized temperature rise, leading to significant temperature gradients across the microprocessor, which is the primary reason for its inadequate performance and early failure. This study proposes microchannel-pinfin hybrid heat sinks incorporating twisted and non-twisted pinfins of various cross-sectional shapes (hexagonal, pentagonal, square, and triangular) to demonstrate energy-efficient hotspot mitigation in a microprocessor with highly non-uniform power distribution. Microchannels and pinfins are positioned at low- and high-heat-flux zones, respectively, to reduce the temperature variations utilizing their unequal heat transfer capabilities. Here, high- and low-heat-flux zones represent the microprocessor-core area (hotspot) and remaining chip area (background zone), characterized by heat fluxes of 300 W/cm2 and 50 W/cm2, respectively. The pinfin twisting angle varies from 0° to 360° at a step of 45°. Conjugate heat transfer analyses are conducted through numerical solutions of the continuity, Navier-Stokes, and energy equations. The performance of the proposed hybrid heat sinks is compared with the non-hybrid (NH) and hybrid circular pinfins (HCP) heat sinks at Re = 120–440. The hybrid heat sink featuring triangular pinfins twisted at 225° angle (HTP-225) exhibits a remarkable reduction of 48.2 % in the total thermal resistance (Rth) and 58.4 % in the temperature non-uniformity (δT,bs) as compared to the NH heat sinks at Re = 440. Compared to the HCP design, the HTP-225 design shows 26.9 % and 35.8 % lower Rth and δT,bs, respectively. Moreover, the HTP-225 heat sink outperforms the NH heat sink with 46.0 % and 57.0 % lower Rth and δT,bs, respectively, at an equal pumping power of 18.6 mW. Furthermore, the HTP-225 heat sink demonstrates a 96.4 % and 38.5 % higher critical hotspot heat flux dissipating capacity than the NH and HCP heat sinks, respectively, making it a viable and effective solution for alleviating hotspots in high-power-density devices.

Enclosed thermal management method for high-power photovoltaic inverters based on heat pipe heat sink

Photovoltaic (PV) inverter plays a crucial role in PV power generation. For high-power PV inverter, its heat loss accounts for about 2% of the total power. If the large amount of heat generated during the operation of the inverter is not dissipated in time, excessive temperature rise will reduce the safety of the devices. This paper proposes a closed PV inverter structure based on heat pipe and liquid cooling which overcomes the noise, dust and other problems caused by traditional air-cooling heat dissipation method and reduces cost of the volume occupied inside the body. Heat is dissipated through heat pipes, which are efficient heat transfer units. A simulation model of the actual cabinet was established using computational fluid dynamics (CFD), and the maximum junction temperature in the inverter was investigated under different coolant temperatures, flow rates, cooling liquid and heat loads. The results showed that the liquid cooling heat dissipation structure can effectively dissipate the heat inside the cabinet. The impact of two different types of heat sink used for power modules on temperature uniformity was studied. The results indicated that the 9-heat pipe type heat sink has better heat dissipation and uniform hot spots performance, the maximum heat source temperatures in the chip and capacitor were reduced by 9.91?C and 7.49?C respectively. Finally, the performance of the two types of radiators under different heat loads was studied.

Pontryagin’s Minimum Principle-Based Power Management of Plug-In Hybrid Electric Vehicles to Enhance the Battery Durability and Thermal Safety

Temperature affects the battery aging and stability, bringing about significant effects on the electric vehicle’s economy, reliability, and safety. Therefore, it is necessary to consider the battery thermal condition when designing the power management scheme. In this paper, an optimal power management strategy for plug-in hybrid electric vehicles is proposed based on Pontryagin’s Minimum Principle (PMP). Two situations, normal operation and cooling system failure, are considered. The impacts of battery aging and temperature rise are characterized based on durability analysis model and thermal model. The temperature variation rate of the battery is incorporated into the Hamiltonian function, and the correlation between the cost optimization and temperature rise is disclosed by shooting method. Then the optimal co-state variables in different cases are determined. Based on above efforts, the PMP-based multi-objective optimal control strategy is proposed and evaluated based on the temperature statistical data in Shenyang, China. The results show that the proposed method can improve the durability of the battery and inhibit the excessive temperature rise. In case of the cooling system failure, it can realize the trade-off between safety and economy to reduce the risk of battery thermal runaway.

The heat is on: the impact of excessive temperature increments on complications of laser treatment for ureteral and renal stones

ObjectiveTechnological advancements in the field of urology have led to a paradigm shift in the management of urolithiasis towards minimally invasive endourological interventions, namely ureteroscopy and percutaneous nephrolithotomy. However, concerns regarding the potential for thermal injury during laser lithotripsy have arisen, as studies have indicated that the threshold for cellular thermal injury (43 °C) can be exceeded, even with conventional low-power laser settings. This review aims to identify the factors that contribute to temperature increments during laser treatment using current laser systems and evaluate their impact on patient outcomes.Materials and methodsTo select studies for inclusion, a search was performed on online databases including PubMed and Google Scholar. Keywords such as 'temperature' or 'heat' were combined with 'lithotripsy', 'nephrolithotomy', 'ureteroscopy', or 'retrograde intrarenal surgery', both individually and in various combinations.ResultsVarious strategies have been proposed to mitigate temperature rise, such as reducing laser energy or frequency, shortening the duration of laser activation, increasing the irrigation fluid flow rate, and using room temperature or chilled water for irrigation. It is important to note that higher irrigation fluid flow rates should be approached cautiously due to potential increases in intrarenal pressure and associated infectious complications. The utilization of a ureteral access sheath (UAS) may offer benefits by facilitating irrigation fluid outflow, thereby reducing intrapelvic pressure and intrarenal fluid temperature.ConclusionAchieving a balance between laser power, duration of laser activation, and irrigation fluid rate and temperature appears to be crucial for urologists to minimize excessive temperature rise.

Evaluating the Ge: C ratio on the bonding structure, hardness, and residual stress of Ge1-x-Cx coatings fabricated by the PE-CVD method

In the present research, the effect of the Ge: C ratio was evaluated and explained on the bonding structure, the hardness, and residual stress of germanium-carbon (Ge1-x-Cx) coatings fabricated by plasma-enhanced chemical vapor deposition (PECVD) method. For characterizing the coatings, a field emission scanning electron microscope (FE-SEM) equipped with an energy dispersive spectrometer (EDS), transmission electron microscope (TEM), Raman spectrometer, Rutherford backscattering spectrometer (RBS), elastic recoil detection (ERD) analysis, X-ray photoelectron spectrometer (XPS), nanoindentation test, and cohesion test were used. by increasing the flow rate ratio of CH4:GeH4 and as a result of decreasing the ratio of Ge: C, the fraction of sp2 C-C and sp3 Ge-C bonds were increased and the fraction of Ge-Ge bonds was decreased. The hardness of the Ge1-x-Cx coatings was heavily reliant on changes in the Ge: C ratio and, consequently, the fraction of the bonds incorporated within the coating structure. To achieve a hard coating, the selection of a moderate carbon content is very important such that it would lead to the formation of maximum sp3 Ge-C bonds alongside slight amounts of sp2 C-C and hydrogen bonds. For very low carbon concentrations, the existence of dominant Ge-Ge bonds would create the coating structure as germanium-like; the excessive rise of the carbon concentration promotes the undesirable graphite-like structures. In the optimum conditions, the hardness of the coating was obtained at 10.1 GPa. The coatings presented a very low residual stress (∼98-240 MPa) despite having suitable hardness.

Preliminary assessment of the potential for rapid combustion of pure ammonia in engine cylinders using the multiple spark ignition strategy

In pursuit of carbon neutrality, the adoption of zero-carbon fuels in internal combustion engines offers a path to zero carbon emissions. Among such fuels, ammonia (NH3) stands out as an effective hydrogen energy carrier with a higher energy density and a more advanced production-storage-transportation lifecycle than hydrogen (H2) fuel, making it a superior alternative. Nevertheless, achieving high combustion efficiencies in engine cylinders requires the use of fuels with fast flame speeds, since the time scales of the combustion event are practically milliseconds. The inherent flame speed of NH3 falls short, typically necessitating augmentation with H2. Yet, the in-situ generation of H2 from NH3 remains constrained, rendering the flame speed of NH3 less competitive against traditional fuels like gasoline and natural gas. To address the dual challenges of slow flame speed of NH3 and the difficulty of generating large amounts of H2 from NH3 onboard, this study evaluates an alternative method of accelerating the ammonia combustion in the engine combustion chamber through the use of multiple spark plugs, which is limited discussed in existing research. Numerical simulations performed in this study show that the application of the multi-spark strategy increases the mass burn rate, advances the combustion phasing, shortens the combustion duration, increases the engine power output, improves the fuel economy, and reduces the unburned ammonia emissions, all of which indicate that rapid combustion of pure ammonia is achieved in the combustion chamber. Moreover, the use of multiple spark points does not lead to a marked increase in nitrogen oxides emissions, thereby ensuring no added stress on exhaust aftertreatment systems. In addition, pure ammonia combustion appears to be very well adapted to this strategy, as evidenced by the avoidance of excessive cylinder pressures and pressure rise rates—a challenge faced by conventional spark ignition engines, given ammonia notably slower flame speed relative to conventional petroleum-based fuels. Overall, all these findings strongly support that the multi-spark ignition system presents a compelling direction for future zero-carbon ammonia engines. However, it is crucial to address design challenges to ensure that the engine head layout provides sufficient cooling, structural robustness, optimal breathing efficiency, and reliable multi-ignition events within the confined space.

Valve Setting Using Fuzzy Logic Method To Control Main Engine Coolant Flow

The main objective of this research is to improve the operating efficiency and performance of ship main engines by optimizing coolant flow. Improper coolant flow can cause excessive temperature rise in the engine, which in turn can reduce engine life and efficiency. In this research, the coolant flow control system is implemented using the fuzzy logic method. Fuzzy logic allows modeling that is more adaptive to parameter variations and uncertainties in the operational environment. Fuzzy rules are developed based on practical knowledge of experts and operational data related to the host machine. The test was carried out through a simulation using a water flow control circuit that supplies the coolant to the ship's main engine with the main components being an ESP32 microcontroller chip and three DS18B20 temperature sensors. The results of this research show that the use of fuzzy logic in regulating coolant flow is able to provide a faster and more accurate response to changes in engine operational conditions. This has the potential to increase cooling efficiency and prevent engine over-temperatures, which can ultimately increase the overall service life and performance of the host engine. The practical implications of the results of this research can be applied in the development of more intelligent and adaptive control systems for various types of host machines, with the potential to increase operating efficiency and reduce the risk of damage due to excessive temperatures

Direct Temperature Measurements of Cardiac Stent during MRI Examinations

Nowadays, Magnetic Resonance Imaging (MRI) is considered the gold standard for imaging the brain, spinal cord, musculoskeletal system, head and neck, and complex congenital heart malformations; consequentially, the number of MRI scans in patients with implantable electronic devices has simultaneously increased. During the entire length of the MRI exam, patients are exposed to electromagnetic fields with different characteristics (static, low frequency, radiofrequency fields), which are related to different risks. The scarce available literature about MRI-induced heating on cardiac stents suggests that excessive temperature rise occurs only in unfavorable cases. Ideally, RF safety assessment could be performed during the anamnestic process, but this simulation process’s results are too slow to be performed before patient MRI examination. In this context, we developed a dedicated measurement set-up by focusing our target on the measurement of the heating of a cardiac stent during an MRI examination. Results for the temperature rise trend along the entire stent length during a clinical MRI protocol are shown together with the local Specific Absorption Rate (SAR) values and cumulative equivalent minutes at 43 °C (CEM43°C), in order to ensure the safety of patients with MR-conditional devices, also with a view to not inappropriately preclude their access to MRI scans. The obtained results show that the maximum temperature rise (4.12 °C) is within the limit of 5 °C stated in the stent manual for 15 min of continued scanning with the specific conditions. The maximum temperature rise was in correspondence with the stent tips and calculated SAR confirms the fact that two hotspots are present near the tips of the stent. Finally, the calculated CEM43°C remained well below the proposed threshold for muscle tissue.