Decrease In Velocity Research Articles

Relationship between hemoglobin, hemolysis, and transcranial Doppler velocities in children with sickle cell disease: Results from a long-term natural history study in Italy in the era of multimodal therapy.

Stroke and cerebral vasculopathy are leading causes of morbidity and mortality in patients with sickle cell disease (SCD). Transcranial Doppler (TCD) is a reliable and validated predictor of stroke risk. Children with conditional or abnormal TCD are at an increased risk for stroke, which can be mitigated by red blood cell transfusion or hydroxyurea. Elucidating the relationship between cerebral hemodynamics and hemolytic anemia can help identify novel therapeutic approaches to reduce stroke risk and transfusion dependence. This long-term, real-world study was designed to evaluate the prevalence of TCD imaging (TCDi)-assessed flow velocities in children and to interrogate their relationship with markers of anemia and hemolysis. In total, 155 children (median follow-up 79.8 months, 1358.44 patient-years) had 583 evaluable TCDi results. Only patients with HbSS or HbSβ0 had abnormal (1.6%) or conditional (10.9%) TCDi. Children with abnormal or conditional TCDi had lower hemoglobin (Hb) and higher hemolysis markers. A linear correlation was detected between TCD velocity and Hb: an Hb increase of 1 g/dL corresponded to decreases in velocity in the internal carotid and middle cerebral arteries (6.137 cm/s and 7.243 cm/s). Moreover, patients with Hb >9 g/dL presented a lower risk of TCDi-associated events. These results support the need to optimize disease-modifying treatments that increase Hb and reduce hemolysis for stroke prevention in young children with SCD.

Homogeneity of Bored Piles According to Results of Four-Channel Cross-Well Ultrasonic Monitoring

The homogeneity of the structure of the boired pile shaft has been studied based on the results of four-channel inter-well ultrasonic (US) monitoring. The actual lengthy of the piles has been determined with the detection of defragmentation of the pile shaft, the compressive defects have been determined, and continuity defects have been identified based on a joint analysis of data from the method of interwell ultrasonic monitoring. The use of four channels allows to control separately the peripheral and central areas of the pile in six directions. The data of the seismoacoustic method coincided with the parameters of ultrasonic monitoring in terms of identifying zones of concrete heterogeneity, reducing the pile cross section, etc. For all of the listed piles, data are not registered by the named test methods indicating defragmentation of the pile shaft – the presence of sections in the cross sections of which there is no concrete at all. These test methods for all piles confirmed the compliance of their actual length with the design values. A significant defect in the continuity of the concrete of the 40op pile, according to the data of ultrasonic monitoring and seismoacoustic method, was registered in the interval of marks – (17.5–18) m, manifesting itself a sa decrease in the propagation velocity of the ultrasonic pulse from 25 to 50 % in two sounding directions, inclu-ding diametrical. This defect can be interpreted as a decrease in the effective section of the pile to 25–50 % of the average value. Defective sections of piles were found in their upper part at depth marks from 0 to –1.5 m, counting from the end surface of the head. At the same time, differences in the physical and mechanical parameters of concrete at these marks were also observed within the cross section of piles [1–5].

Late Decrease in Cerebral Blood Flow in Bacterial Meningitis: More than a Simple Normalization of Acute Inflammatory Vessel Wall Architecture?

Acute bacterial meningitis is a disease with an overwhelmingly high mortality rate and high incidence of adverse neurological sequelae and poor neurological recovery amongst survivors. Amongst the numerous complications of bacterial meningitis, the presence of cerebrovascular disease represents a severe disease form. Vascular involvement during bacterial meningitis has long been established by numerous pathological and angiographic studies. Cerebrovascular changes known to occur in bacterial meningitis ranging from narrowing of large arteries by vasospasm to critical stenosis/obliteration of small to medium sized arteries/arterioles by vasculitis. Not surprisingly, alterations in CBF velocities have commonly been described during the inflammatory process and may represent an important component of brain injury during meningitis. In accordance with previous studies observing a biphasic cerebral flow pattern characterized by an early but transient increase in flow velocity, mostly due to reflexive vasospasm, and later by a sustained decrease in flow velocity, likely attributable to stenotic vasculitis, cerebral ischemia is a notable complication of bacterial meningitis during the advanced disease phase. Impaired cerebral perfusion during the late stages of disease may result from a variety of factors that contribute to a vital component of cerebral injury in bacterial meningitis. The pathogenesis of cerebral ischemia with progression of disease course is less clearly understood but may involve a complex interaction between inflammatory processes, systemic dysfunction, energy impairment, neuronal damage and intracranial pressure, factors of which we aim to more precisely understand and assign a more definite contributory role in the development of cerebrovascular ischemic consequences with advanced stages of bacterial meningitis.

Hepatic Artery and Portal Vein Hemodynamics in Nonalcoholic Fatty Liver Disease in Adult Saudi Patients: A Doppler Ultrasound Study

Background: Nonalcoholic fatty liver disease (NAFLD) is a growing public health problem. With the growing severity of NAFLD, there are considerable alterations in the hemodynamics of the hepatic circulation that might affect the prognosis of the condition, according to numerous reports written to assess the vasculature of the liver in patients affected with fatty liver disease. The aim of the study was to examine hemodynamic alterations in the hepatic artery (HA) and portal vein (PV) in NAFLD patients and determine how they relate to the severity of the condition, and to classify patients into various categories of NAFLD and connect the results to liver size and body mass index (BMI). Methods and Results: One hundred and six diagnosed NAFLD patients who attended the Imaging department at King Fahad Hospital from December 2019 to January 2020 were retrospectively studied. The mean age of the patients was 45.75±15.6 years, with a range of 10-79 years. The patients were examined by a TOSHIBA Xario, SSA-660A ultrasound system utilizing a multifrequency convex transducer (2–5 MHz) for all sonographic exams. B-mode assessed the liver parenchyma, and spectral Doppler estimated the HA and PV. The US appearance of hepatosteatosis, according to the severity of echogenicity, was graded (0-3). Most participants were asymptomatic (76.4%), and diabetes and diabetes with hypertension were diagnosed in 12.3% and 11.3%, respectively. It was observed that grade 1 hepatosteatosis was more prevalent than the other grades: 54 cases versus 41 cases for grade 2 and 11 cases for grade 3. The mean values of liver size and BMI in grade 3 were higher than in grade 1 (P=0.0033 and P=0.0054, respectively). A Spearman test found that the liver size (R=0.19, P=0.05) and BMI (R=0.26, P=0.01) had weak positive, but statistically significant, correlations with the severity of the hepatosteatosis grade. Doppler indices of the HA and PV in NAFLD patients did not differ significantly in hepatosteatosis grades 1-3. Only the PSV and EDV of the main PV showed a significant decrease in the hepatosteatosis grade 2 compared to grade 1 (P=0.0065 and P=0.0234, respectively). Despite the insignificant differences, the Doppler flow parameters of the HA decreased with the severity of hepatic steatosis; for example, the hepatic artery resistive index (HARI) was 0.77±0.16 in grade 1, 0.72±0.16 in grade 2, and 0.75±0.10 in grade 3, respectively. The hepatic artery pulsatility index (HAPI) was 1.62±49 in grade 1, 1.63±.68 in grade 2, and 1.74±0.77 in grade 3. There was also a trend toward a decrease in PSV and end-diastolic velocity (EDV) of HA with the severity of hepatosteatosis. Conclusion: The severity of hepatic steatosis is significantly correlated with liver size and BMI. The blood flow parameters of PV and HA decrease with the severity of hepatic steatosis except for the pulsatility index.

Effect of the Solidification Mode on the Pore Growth of Gasar Porous Mg‐Ag Alloy

AbstractGasar porous Mg–3 wt% Ag alloy is prepared by metal–gas eutectic directional solidification process. The pore structure is related to the solidification mode of the alloy. The pores grow stably under the solidification conditions of planar, cellular, and columnar dendrites but not under the condition of equiaxed dendrites. The numerical simulation shows that the solidification velocity and temperature gradient decrease rapidly with an increase in the sample height, but their ratio remains unchanged. During the solidification process, the solidification mode of the alloy changes from cellular crystals to columnar dendrites, and finally to equiaxed dendrites. The calculated results of the solidification mode transition are consistent with the microstructure morphologies of the Mg–Ag alloy at different heights.

Intravenous thrombolysis for bioprosthetic valve thrombosis.

A 77-year-old woman experienced new-onset dyspnoea on exertion 1 year after alcohol septal ablation and transcatheter aortic valve implantation (TAVI) with a balloon-expandable valve for symptomatic severe aortic stenosis and basal septal hypertrophy. Transthoracic echocardiographic assessment (TTE) revealed an incremental transvalvular peak velocity from 2.9 m/s 3 days after TAVI to 4.3 m/s. Multislice computed tomography (MSCT) demonstrated hypoattenuated leaflet thickening (HALT) of all leaflets and reduced leaflet motion (RLM) of one leaflet (Panel A). Her antithrombotic regimen was changed from apixaban 5 mg bi-daily to acenocoumarol with a target international normalized ratio (INR) of 2.5–3.5. Six weeks later, symptoms persisted and the transvalvular peak velocity was 3.9 m/s (Panel B). A decision was made to attempt to resolve the thrombus with repeated intravenous infusions of alteplase.1,2 Four sequential infusions of 25 mg alteplase/25 h resulted in an uneventful but stepwise decrease of the transvalvular peak velocity to 2.8 m/s (Panel C–F). Multislice computed tomography confirmed normalization of leaflet motion with some residual remaining leaflet thickening (Panel F). MSCT cine images before and after alteplase infusion are available in the Supplementary data online (Videos S1 and S2).

Hydrodynamic Model due to Reclamation in Lamong Bay

PT. Teluk Lamong Terminal is one of the busiest port terminals in Indonesia. Such conditions require the development of the facility area for reclamation. This reclamation can potentially change the seabed’s contours and current patterns in the Lamong bay area of Surabaya. Therefore, the Author will conduct a research study to determine the impact of reclamation on the speed and current pattern of the existing and post-reclamation conditions in Lamong bay, Surabaya. This research conducted numerical modeling with Delft3D software. The simulation results show that the current pattern at the highest tide in the existing and reclamation models tends to have a dominant current direction from east to the northwest in the Madura strait. In contrast, some currents from the Madura strait are deflected into the Lamong bay area. On the other hand, during the lowest low tide conditions, both existing and reclamation conditions, the current pattern has a dominant direction coming from the northwest to the east, and the current in the Lamong bay area tends to exit or towards the Madura strait. There is an increase or decrease in current velocity when reclamation is carried out in each tidal condition. The highest increase in current velocity occurs at high tide with a value of 0.02 m/s, while the highest decrease in current velocity occurs at the high tide of 0.13 m/s. At the lowest ebb conditions, the highest current speed increase is 0.12 m/s, and the highest current velocity decrease is 0.03 m/s.

Improved Characterization of Ultralow‐Velocity Zones Through Advances in Bayesian Inversion of ScP Waveforms

AbstractUltralow‐velocity zones (ULVZs) have been studied using a variety of seismic phases; however, their physical origin is still poorly understood. Short period ScP waveforms are extensively used to infer ULVZ properties because they may be sensitive to all ULVZ elastic moduli and thickness. However, ScP waveforms are additionally complicated by the effects of path attenuation, coherent noise, and source complexity. To address these complications, we developed a hierarchical Bayesian inversion method that allows us to invert ScP waveforms from multiple events simultaneously and accounts for path attenuation and correlated noise. The inversion method is tested with synthetic predictions which show that the inclusion of attenuation is imperative to recover ULVZ parameters accurately and that the ULVZ thickness and S‐wave velocity decrease are most reliably recovered. Utilizing multiple events simultaneously reduces the effects of coherent noise and source time function complexity, which in turn allows for the inclusion of more data to be used in the analyses. We next applied the method to ScP data recorded in Australia for 291 events that sample the core‐mantle boundary beneath the Coral Sea. Our results indicate, on average, ∼12‐km thick ULVZ with ∼14% reduction in S‐wave velocity across the region, but there is a greater variability in ULVZ properties in the south than that in the north of the sampled region. P‐wave velocity reductions and density perturbations are mostly below 10%. These ScP data show more than one ScP post‐cursor in some areas which may indicate complex 3‐D ULVZ structures.

Design of a highly efficient n-CdS/p-AgGaTe2/p+-SnS double-heterojunction thin film solar cell

In this article, AgGaTe2-based n-CdS/p-AgGaTe2/p + -SnS double-heterojunction solar cells have been designed and explored utilizing a solar cell capacitance simulator (SCAPS-1D). This design manifested n-type CdS and p + -type SnS as window and back surface field (BSF) layer, respectively with the AgGaTe2 absorber. The major contributing parameters of these layers such as thickness, doping concentration level, and bulk flaws have been adjusted to reach the optimum computation. This introduced n-CdS/p-AgGaTe2/p + -SnS double-heterostructure solar cell demonstrates the significant power conversion efficiency (PCE) of 32.48% with the open circuit voltage, VOC of 0.96 V, short circuit current, JSC of 38.64 mA cm−2, and the Fill factor, FF of 87.31%. This remarkable efficiency is originated by the formation of a higher built-in potential at the p-AgGaTe2/p + -SnS heterostructure and a decrease in the surface recombination velocity brought on by the SnS BSF layer. This computational study demonstrates the potential of AgGaTe2 as an absorber and SnS as a BSF layer, and pave the way for the AgGaTe2-based experimental research in the era of solar cells.

Modeling and simulation on dynamic engraving process of small caliber armor-piercing projectile with lead-free aluminum filler

In order to reduce the ineffective armor-piercing weight of the small caliber armor-piercing projectile, improve combat effectiveness, and reduce the pollution of lead fillers to the environment, a projectile with aluminum filler was proposed. Taking the small caliber armor-piercing projectile as the research object, using explicit dynamic methods and coupling the classical internal ballistic equations, a numerical simulation model of bullet–barrel interactions during dynamic engraving process was established. And the reliability of the model was verified by the dynamic engraving experiment. Besides, using copper and copper-clad steel (CCS) as the jacket material, and aluminum and lead as the filler material, numerical simulation studies of four schemes were carried out. The result shows that, the aluminum filler projectile will cause a slight increase in the maximum chamber pressure and a slight decrease in the muzzle velocity of the projectile, an increase in the sliding friction force and a decrease in the maximum deformation force, an increase in the contact stress on both sides of the land and a decrease in the contact stress on the land and groove. And the contact stress on the non-driving side is larger than that on the driving side. The average contact stress and the engraving resistance of the Cu-Al case and CCS-Pb case are very close. And the application of Cu-Al projectile may improve the shooting accuracy in the hot barrel conditions compared with Cu-Pb projectile, and achieve the same performance as CCS-Pb projectile.

Conditioned medium and secretome from epididymal epithelial cell cultures improve sperm kinetics and capacitation.

Sperm maturation occurs in the epididymis through interactions with existing molecules inside the lumen. However, the mechanism of epididymis molecular transfer is currently unclear. This study was aimed to determine the necessity of the epididymal epithelial cells (EECs) in the process of sperm maturation in terms of sperm kinetics and tyrosine phosphorylation. A true experimental research design was used in this study. The medium tested was a primary culture of mice caput epididymal cells (cells and culture medium), conditioned medium (CM) (supernatant of EECs), and secretome (CM filtered at 0.22 μm). Sperm was cocultured in EEC culture, CM, and secretome for 1, 2, 3, or 4 h. The original culture medium was used as the control. Sperm kinetic analysis was performed after the indicated times using computer-assisted sperm analysis, and tyrosine phosphorylation was detected using the Western blot technique. A primary culture of caput EECs was successfully generated. The results showed increased sperm motility and progressive movement after 3 h of incubation (p < 0.05). There was a significant decrease in the average path velocity (VAP) values after 4 h of incubation (p < 0.05), but there was no significant change in the 1, 2, and 3 h incubation groups. The EEC culture-CM and secretome groups showed a significant increased progressivity and VAP percentage values compared with the control medium (p < 0.05). In terms of percentage motility, the culture and CM groups were significantly different from the control medium, but the secretome group was not. The sperm kinetics of sperm cultured in CM, secretome, and EEC were significantly increased after 3 h of incubation, suggesting that CM and secretome can be used to replace EECs, especially when analyzing molecules secreted by the epididymal epithelium during sperm maturation. The results of this study highlight the potential of CM and secretome as therapy mediums for sperm kinetic abnormalities.

Ключевые вопросы создания надувных тормозных устройств для увода вышедших из строя спутников в плотные слои атмосферы. Часть 2. Анализ теплового режима в условиях комбинированного нагрева

The promising solution in reducing pollution of the low Earth orbits by space debris consisting of artificial satellites, other spacecraft and elements of the launch vehicles and upper stages that exhausted their resources lies in introduction of the inflatable braking devices. The simplest version of such a system could be a thin-walled shell made of polymeric material being stored in a folded form in the satellite’s transport container and being inflated at the right time on command acquiring the given configuration. Large area of the shell midsection provides an increase in the braking force in the highly rarefied atmosphere and a decrease in the flight velocity followed by a descent into the atmosphere dense layers for liquidation. Selection of the rational parameters for the braking device inflatable shell provides for solution of rather complex interdisciplinary problems. Among them, the task of determining the inflatable shell temperature state is distinguished, which would be formed exposed to action of the thermal radiation fluxes from the Sun, the Earth and kinetic heating caused by motion in the free molecular medium. Heat transfer specifics of the thin-walled spherical shell of an inflatable braking device designed to remove the obsolete CubeSat-class nanosatellites positioned in the low Earth orbits were considered.

High velocity ballistic performance of ZrSiO4 reinforced aluminum alloy matrix composites

Multi-layered composite structures are a suitable strategy for achieving superior ballistic performance as compared to the monolithic materials. Typically, in the multi-layered structures, high hardness and strength material is configured as a front face and highly deformable material in the back layers. In the present study, ceramic particles ZrSiO4 reinforced Al-Si12Cu (LM13) aluminum alloy composites are investigated for ballistic performance. The 15 wt% ZrSiO4 particles of different sizes 20, 60 and 120 µm are incorporated in the aluminum alloy matrix via stir casting technique. Ballistic impact tests were performed by firing 0.308 calibers bullets with AK-47 rifle from a distance of 10 m. The deformations of the composite plates are predicted by correlating the decrease in the final velocity of the bullet after impact. It was found that composite reinforced with finer size particles offered higher resistance to bullet penetration as compared to the coarse size reinforced particles. The residual velocity as compared to the striking velocity was reduced to ∼34%, ∼29% and ∼22% for composite reinforced with ZrSiO4 particles of 20, 60 and 120 µm, respectively. At exit face the spall diameter is 34, 30 and 17 mm for composite of particle size 20, 60 and 120 µm, respectively. Microstructural analysis of the affected zones is also performed to explore the behavior of composite under the high impact loading.

NUMERICAL STUDY OF BIOMAGNETIC MAXWELL FLUID PAST A NONLINEARLY STRETCHING SHEET WITH CONSIDERING MAGNETIZATION AND ELECTRICAL CONDUCTIVITY

This study goal is to examine the flow of two-dimensional biomagnetic Maxwell fluid past a nonlinearly stretched sheet while it is subject to an applied magnetic field that is produced by the presence of a magnetic dipole. Assumedly, the fluids magnetization M varies linearly with temperature T and magnetic field strength H. Consideration is given to the effects of magnetohydrodynamics (MHDs) and ferrohydrodynamics (FHDs) on the flow. The controlling nonlinear partial differential equation is presented with similarity transformations to change it into coupled ordinary differential equations. These equations are then numerically solved with the help of common finite differences method. The influence of the addressed problem parameters, namely, magnetic parameter [Formula: see text], ferromagnetic parameter [Formula: see text], Deborah number [Formula: see text] and nonlinear stretching parameter [Formula: see text] on the flow profile is discussed with the help of graphical demonstration. The obtained results show that the fluid velocity increases near the wall but its reverse after a fixed point from the wall with increases nonlinearity stretching parameter. The study also demonstrates that as the magnetic field intensity increases, the temperature distributions increase while the fluid velocity decreases. It was also discovered that, in contrast to the situation of pure hydrodynamics, the effect of MHD or FHD interaction is to slow down the fluid velocity. By making numerous comparisons with previously published work, the numerical method accuracy is examined, and the comparisons show that the results are generally in good accord. Along with the flow parameters, physical parameters like the dimensionless Nusselt number and the skin friction coefficient are shown. The study will be crucial for applications in medicine.

Damage Time-Dependent Characteristics and Failure Mechanism of Limestone with Different Mineral Compositions Under Acid Hydro-Chemical Solution Erosion

Taking two types of limestone with different mineral compositions as research objects, we conducted experiments on the mass, longitudinal wave velocity, ion concentration of solution, fracture morphology, and micromorphology of two types of limestone specimens eroded by acidic hydro-chemical solution. We investigated specimens’ damage time-dependent physical properties, dissolution, structure, discussing mineral composition effects and destruction. Results show that the mass loss rate of two types of limestone specimens eroded by acidic hydro-chemical solution increases with the increase of immersion time in a power function, and the longitudinal wave velocity decreases and then fluctuates in a small range. The specimen fracture degree increases with the increase of the immersion time, and the rock micro-structure changes from dense and uniform into loose and porous. The mass, the longitudinal wave velocity, the fracturing morphology, and damage to microscopic morphology of specimens increase with the increase of solution ion concentration. The acid rock reaction rate of limestone A is lower than that of limestone B, while the hydrolysis reaction rate is higher. The mass loss rate, the longitudinal wave velocity loss rate, the ion concentration, and the damage degree of the macro-and micro-structure of limestone A are higher than that of limestone B.

Glucagon-like peptide-1 receptor agonists as a disease-modifying therapy for knee osteoarthritis mediated by weight loss: findings from the Shanghai Osteoarthritis Cohort

ObjectiveObesity is a risk factor for knee osteoarthritis (KOA) development and progression. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are indicated for type 2 diabetes mellitus (T2DM) and obesity. However, whether KOA...

Study of Fluidization Behavior Transition from Geldart B to A Induced by High Temperature Using Electrical Capacitance Tomography

The transition of the fluidization behavior of Geldart B particles to that of A particles induced by temperature change was investigated by a developed high-temperature electrical capacitance tomography (ECT) sensor. Silica particles with a Sauter mean diameter of 237 μm and density of 2650 kg/m3, typically Geldart B particles under ambient conditions, were fluidized in a column of 5.5 cm from 20 to 600 °C. With the increase in temperature, ECT measurements showed a decrease in minimum bubbling velocity (Umb), no bed expansion characteristic in the homogeneous fluidization regime, an absence of multiple-bubbles regime, and a larger bubble size. The pressure drop against superficial gas velocity curves at elevated temperatures confirmed homogeneous fluidization between the minimum fluidization velocity (Umf) and Umb. Our analysis demonstrates that cohesive interparticle forces, which increase linearly with temperature, are responsible for the fluidization behavior transition of the silica particles.

Study of porous silicon layer effect in optoelectronics properties of crystalline silicon

In this research, we experimentally and numerically demonstrate the beneficial effect of superficial porous silicon layer in the optoelectronics properties of multi-crystalline silicon. The hydrogen and oxygen-rich porous silicon layer was formed using vapor etching method. From laser beam induced current (LBIC) simulations, we found that the hydrogen and oxygen-rich porous silicon layer used in mc-Si surface acts as a good surface passivation and a potential candidate for electronic quality and optoelectronics properties improvement. As a result, the generated current of treated silicon is 5 times greater as compared to reference substrate, which led to a 50% increase of the minority carrier diffusion length, 25% decrease in the recombination velocity of the minority carrier and the reflectivity reduced from 38 to 3% of the related sample.

Evaluation of AGM and FEM method for thermal radiation on nanofluid flow between two tubes in nearness of magnetism field

The nanofluid flow through two orbicular cylinders is explored utilizing the overall Koo–Kleinstreuer–Li (KKL) model within the nearness of a magnetic field. The impact of thermal radiation is considered in the energy equation. The novelty of this study is examining convective heat transfer for nanofluid flow between two flat tubes with the Akbari-Ganji method and Finite Element Techniques to examine the heat flux field by implies of 2D forms of temperature and velocity at unprecedented Reynolds numbers. The approaches for solving ODEs are AGM and FEM. Semi-analytical methods are assessed for specific parameters of aspect ratio, Hartmann number, Eckert number, and Reynolds quantity with various values. Adding Ha, Ec, and G causes the temperature gradient to grow, while adding the Reynolds number causes it to decrease. As the Lorentz forces increase, the velocity decreases; nevertheless, as the Reynolds number rises, the velocity decreases. With the reduction of the fluid's dynamic viscosity, the temperature will decrease, which will decrease the thermal trend along the vertical length of the pipes.

Analysis of marine heatwaves and biogeochemistry in the Northern Arabian Sea

Marine heatwaves (MHWs) are abnormal Sea Surface Temperature (SST) conditions in which temperature exceeds the 90th percentile threshold limit. It has significant impacts on marine biodiversity causing large-scale coral bleaching, fish deaths or migration, and local weather changes. Analyzing MHWs and their causative mechanism can help to understand the notable influence on biodiversity. In this paper, we have investigated the MHW events in the Arabian Sea (AS) for the period 1982 to 2021. Our study reveals that an average of two MHW events occur every year with an increasing linear trend of 1.22 MHW events per decade in the northern AS region. In addition, we found a category-II MHW event that lasted about 134 days in the year 2020. This northern AS MHW event has a maximum, mean, and cumulative intensity of about 2.76 °C, 1.94 °C, and 259.35 °C-days (above the climatological mean), respectively, from 9thJune 2020 to 20thOctober 2020. According to our analysis, the western AS showed relatively higher intensity than the eastern part, especially near the coasts. The entire AS showed an increasing trend of MHW. We found that the decrease in wind velocity, increase of net downward heat flux, and lowering of surface ocean current is the main cause of the 2020 northern AS MHW event. Many of the biogeochemistry parameters, namely, chlorophyll (-16.2255%), net primary production (-25.5948%), dissolved oxygen (-0.7323%), nitrate (-23.9284%), and phosphate (-49.2542%) show the lowest values during the 2020 MHW event period except for silicate (13.9649%) for their corresponding climatological mean. Decreasing trends are also observed for chlorophyll (-0.0020 mg/m3-year), net primary production (-0.1747 mg/m3-year), oxygen (-0.1079 mmol/m3-year), nitrate (-0.0080 mmol/m3-year) and phosphate (-0.0076 mmol/m3-year) with increasing MHW days except for silicate that shows an increasing trend of 0.0018 mmol/m3-year with increasing MHW days with time.Plain Language SummaryForty years of SST data is used to find and analyze the most intense MHW events in the Arabian Sea (AS). We calculated its characteristics such as maximum, mean, cumulative intensity, and duration to understand and further analyze these MHW events. We have analyzed the time series of the number of MHW events per year from 1982 to 2021 alongside the trend to understand and predict the future MHW events in the northern AS region. We generated spatial plots of different MHW parameters over the entire AS and tried to understand their behavior. We compared changes in six marine biogeochemistry parameters spatially and temporally with the yearly MHW days and observed their relationship.