Low Diffusion Coefficient Research Articles

Diffusion tensor magnetic resonance imaging in the grading of liver fibrosis associated with congenital ductal plate malformations.

Liver biopsy is still the standard method for the diagnosis of ductal plate malformations (DPM). However, it is an invasive tool. Magnetic resonance imaging (MRI) has shown its accuracy in the diagnosis of this pathology. Herein, a study was conducted to elucidate the role of diffusion MRI parameters in predicting the degree of hepatic fibrosis. This prospective study included 29 patients with DPM and 20 healthy controls. Both groups underwent diffusion tensor magnetic resonance imaging (DT-MRI), and its parameters were compared between patients and controls, and then they were correlated with the degree of liver fibrosis in the patient group. All patients with DPM, whatever its type, expressed a significantly lower hepatic apparent diffusion coefficient (ADC) compared to controls. However, fractional anisotropy (FA) showed no significant difference between them. The ADC value of 1.65 × 10-3 mm2/s had sensitivity and specificity of 82.1% and 90%, respectively, in differentiating DPM patients from healthy controls. It was evident that patients with higher fibrosis grades had significantly lower hepatic ADC, indicating a negative correlation between ADC and the grade of hepatic fibrosis; rs = -0.901, p < 0.001. DT-MRI showed good efficacy in the diagnosis of congenital DPM. Moreover, ADC could be applied to monitor the degree of liver fibrosis rather than the invasive liver biopsy. No significant correlation was noted between the FA and the grades of liver fibrosis.

Investigation on degradation studies and deformation behavior of water diffused Al-epoxy nanocomposites

Polymer nanocomposites are used in the space environment, aerospace structural applications, and power applications due to their good mechanical and dielectric properties. Polymeric materials used in these conditions may absorb moisture, driven by the diffusion due to rain or fog condensation, HVDC cable and aerospace structural parts constituting epoxy based composites would lead to ageing and degradation over a period of time due to environmental and static loading conditions in the actual service conditions. Since the degradation initiate at the surface of the material influencing both dielectric and mechanical properties, surface characteristics of water diffused insulating materials & tensile properties ought to be investigated. The studies through surface characterization methods viz. contact angle, atomic force microscopy (AFM) and water droplet initiated corona inception voltage (CIV) of water diffused Al-epoxy nanocomposites are made and the comparative analysis is performed with their unaged nanocomposites. Tensile properties of the Al-epoxy nanocomposites were investigated for its deformation behavior under static load. The experimental results revealed that the controlled addition of nanofiller has shown the lower diffusion coefficients for the aged nanocomposites. The contact angle measurements have exhibited an inverse relation with the surface roughness measured through AFM. Though CIV characteristics are drastically reduced for water diffused nanocomposites, slight enhancement in these properties is observed with the nanofiller inclusion. The tensile behavior of Al reinforced epoxy nanocomposites is compared with aged composites. © 2016 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the organizing committee of Implast 2016.

Motion of nanovehicles on pristine and vacancy-defected silicene: implications for controlled surface motion.

Understanding the motion of surface-rolling nanomachines has attracted lots of attention in recent studies, due to their ability in carrying molecular payloads and nanomaterials on the surface. Controlling the surface motion of these nanovehicles is beneficial in the fabrication of nano-transportation systems. In the present study, molecular dynamics (MD) simulations alongside the potential energy analysis have been utilized to investigate the motion of C60 and C60-based nanovehicles on the silicene monolayer. Nano-machine simulations are performed using molecular mechanic forcefield. Compared with graphene and hexagonal boron-nitride, the molecules experience a higher energy barrier on the silicene, which leads to a lower diffusion coefficient and higher activation energy of C60 and nanomachines. Overcoming the maximum energy barrier against sliding motion is more probable at higher temperatures where the nanomachines receive higher thermal energy. After evaluating the motion of molecules around local vacancies, we introduce a nanoroad structure that can restrict surface motion. The motion of C60 and nanovehicles over the surface is limited to the width of nanorods up to a certain temperature. To increase the controllability of the motion, a thermal gradient has been applied to the surface and the molecules move toward the lower temperature regions, where they find lower energy levels. Comparing the results of this study with other investigations regarding the surface motion of molecules on boron-nitride and graphene surfaces brings forth the idea of controlling the motion by silicene-based hybrid substrates, which can be further investigated.

Gas desorption and diffusion characteristics in different rank coals under different pressure-drop conditions

To compare gas desorption and diffusion characteristics under different pressure-drop conditions, different rank coals were collected to conduct desorption and diffusion experiments under the direct pressure-drop condition (DPDC) and the progressive pressure-drop condition (PPDC). Moreover, mercury injection capillary pressure (MICP) analysis was performed to determine pore structure characteristics. When the pressure-drop condition is changed from DPDC to PPDC, the initial desorption rate decreases, while the desorption volume and diffusion coefficient increase, suggesting the damage on desorption capacity and diffusion capacity resulted from DPDC. The maximum changes of these three parameters occur in the medium-volatile bituminous coal, which decrease from 0.255 to 0.063 cm3/(g·min), increase from 2.96 to 18.82 cm3/g and increase from 0.4732 × 10−10 to 3.8239 × 10−10 cm2/s, respectively. Micropores and transition pores predominate in all samples. With increasing coal rank, the pore volume generally shows a decreasing trend, whereas the fractal dimension shows an increasing trend. The difference in diffusion coefficient between DPDC and PPDC of different rank coals is predominated by micropores, which arises from the various diffusion regimes at different pressure ranges in micropores. Specifically, the rapid pressure-drop rate in DPDC causes the atmospheric pressure condition, and Knudsen diffusion and Transitional diffusion play dominant roles in micropores, resulting in the lower diffusion coefficient. The difference in desorption volume between DPDC and PPDC of different rank coals is predominated by transition pores, which results from the water block effect in transition pores. In DPDC, large bubbles easily form in transition pore throats and show large deformation when they pass through transition pore throats, which increases capillary resistance and intensifies the water block effect. However, in PPDC, the size of gas bubbles in the same transition pore throats is smaller than that in DPDC, which weakens the water block effect and enhances desorption capacity. This research can provide strategies for optimizing the pressure-drop rate during CBM production. PPDC is more suitable for CBM exploration. The drainage intensity should be reduced, or secondary reformation measures should be taken to reduce the proportions of micropores and transition pores in DPDC to reduce the damage of desorption capacity and diffusion capacity.

Study on the hydrogen barrier performance of the SiOC coating

SiOC coatings were prepared on X70 pipeline steel substrate by a simple dipping method at low temperatures, and their performance of hindering hydrogen penetration was studied through electrochemical hydrogen permeation experiment. The sample thermal-treated at 120 °C achieved a low diffusion coefficient of hydrogen of 8.20 × 10−9 cm2 s−1, which was nearly three orders of magnitude lower than 3.58 × 10−6 cm2 s−1 for the X70 steel. This was due to that the amorphous coating did not provide a stable hydrogen diffusion channel, thus limiting hydrogen diffusion. Density functional theory (DFT) calculation further proved that hydrogen moleculars were difficult to be adsorbed at different sites on the surface of the coating.

Effect of Co-Existing Ions on Salinity Gradient Power Generation by Reverse Electrodialysis Using Different Ion Exchange Membrane Pairs.

This study investigates the influence of co-existing ions on the salinity gradient power generation performance of the reverse electrodialysis (RED) using three different commercial ion exchange membrane pairs. The feed solutions, including the mixture of two different salts, were prepared with 90 wt.% of NaCl and 10 wt.% of LiCl, KCl, CaCl2, MgCl2 or Na2SO4 by keeping the salt ratio between high concentrate solution and low concentrate solution constant as 1:30 (g/g) at various flow velocities (50, 125 and 200 mL/min). It was observed that the divalent ions exhibited a negative impact on the performance of the RED system due to their high valence and low ionic mobility depending on their high hydrated radius and low diffusion coefficients compared to those of the monovalent ions. On the other hand, the effect of the monovalent ions differed according to the properties of ion exchange membranes used in the RED stack. When the power generation performances of ion exchange membrane pairs employed in the RED stack were compared, it was considered that Neosepta AMX and CMX membranes provided the highest power density due to their low membrane thicknesses, low electrical resistances, and relatively high ion exchange capacities compared to other two commercial ion exchange membrane pairs.

High-performance co-continuous Al-Ce-Mg alloy with in-situ nano-network structure fabricated by laser powder bed fusion

A novel Al-Ce-Mg alloy with an in-situ nano-network structure and improved tensile properties was fabricated using laser powder bed fusion (LPBF). The microstructure of the as-fabricated alloy exhibited an extremely fine eutectic Al/Al 11 Ce 3 co-continuous structure, i.e., Al 11 Ce 3 intermetallics with an in-situ nano-network surrounding the interconnected Al matrix. It forms an equiaxed grain in the scanning direction (SD) and columnar grain in the building direction (BD). The yield strength (YS) and ultimate tensile strength (UTS) in SD and BD are 300 ± 11.5 MPa, 438 ± 6.9 MPa, and 303 ± 5.0 MP, 442 ± 3.3 MPa, about three times higher than those of as-cast alloy. The elongations (El) are 9.3 ± 0.7% and 6.2 ± 1.2% in SD and BD, respectively, exhibiting anisotropy. The perfect interfacial bonding between the Al 11 Ce 3 phase and Al matrix combined with nano-scale network structures provided a strong ability to hinder the propagation of microcracks formed within Al 11 Ce 3 particles. Besides, the alloy retained outstanding strength at elevated temperatures with 200 MPa at 300 °C and 100 MPa at 400 °C, which may be attributed to the heat resistance of nano-network Al 11 Ce 3 intermetallics and the extremely low diffusion coefficient of Ce in the Al matrix. This work provides a new idea for developing heat-resistant aluminum alloys with a good combination of strength and ductility via AM processing technique. • Microstructure featured extremely fine eutectic Al/Al 11 Ce 3 co-continuous structure. • Al 11 Ce 3 network is connected by nanocrystalline grains with different orientations. • The as-fabricated Al-Ce-Mg alloy displays superior strength-ductility combination. • The as-fabricated Al-Ce-Mg alloy maintains high strength at elevated temperature.

Molecular mechanism of drug transport and release through zeolitic imidazole framework nanospheres for versatile drug delivery applications

Adsorption and release of doxorubicin (DOX) anticancer drug on two bio-compatible zeolitic imidazolate frameworks (ZIFs), namely ZIF7 and ZIF8, are studied using molecular dynamics (MD) simulation. Furthermore, the diffusion of the studied system into the cell membrane (POPC) is investigated. The obtained results reveal that ZIF7 is favorable for DOX adsorption compared to ZIF8 due to the formation of strong binding with DOX. Furthermore, the low diffusion coefficient value for drug molecules in both ZIFs suggests that they can be interesting candidates for controlled release of the doxorubicin anticancer drug. Moreover, the study of drug release in acidic pH shows that the electrostatic energy in the protonated system is weaker than those in the neutral systems. Our results indicate that DOX remains bound to the ZIFs in its neutral state, yet it is readily released in acidic conditions. Finally, the behavior of the DOX-ZIF7 system near the membrane cell is studied. It is found that the DOX tends to stay near the head of the lipids and cannot be inserted into the POPC bilayer during simulation time while ZIF7 moves away from the lipid membrane. The obtained results from the MD simulation reveal that ZIF7 can deliver the drug to the top of the lipid bilayer.

The influence of sedimentary heterogeneity on the diffusion of radionuclides in the sandy facies of Opalinus Clay at the field scale

Abstract. Radionuclide migration in clay-rich formations is typically dominated by diffusion considering the low permeability of these formations. An accurate estimation of radionuclide migration in host rocks using numerical tools plays a key role in the safety assessment of disposal concepts for nuclear waste. In the sandy facies of the Opalinus Clay (SF-OPA), the spatial variability of the pore space network and compositional heterogeneity at the pore scale (nm to µm) cause heterogeneous diffusion at the core scale (cm to dm). Such heterogeneous diffusion patterns affect the migration of radionuclides in various sedimentary layers even above the core scale (m). In this work, we study the heterogeneous diffusion of cations based on a two-dimensional (2D) structural model at the m-scale. As key parameters for the diffusive transport calculation, the effective diffusion coefficients in different sedimentary layers are quantified based on our previous developed up-scaling workflow from pore- to core-scale simulation combined with the multi-scale digital rock models. The heterogeneous effective diffusivities are then implemented into the large-scale structural model for diffusive transport simulation using the FEM-based OpenGeoSys-6 simulator. The sensitivity analysis focuses on the effects of the SF-OPA bedding angle and the effect of different layer-succession layout with different canister emplacement on the spatio-temporal evolution of radionuclide diffusion front line. Results show that the moving distance of the diffusion front is farther away from the canister center, along the direction with the neighboring layer having lower diffusion coefficient within the total simulation time of 2000 years. When the bedding angle increases, the diffusion front moves farther in in vertical upward direction direction, which has less retardation effect for the radionuclide from the ground surface point. For different layer-succession layout with different canister emplacement, the smallest migration distance of the diffusion front line is 1.65 m. Within 2000 years, for the conceptual model 2B that the canister is emplaced in the layer with the highest diffusivity coefficient, the diffusion front can migrate 0.19 m farther along vertical downward direction due to the influence of the neighboring layer. The numerical results provide insight into the effects of rocks heterogeneity on diffusion of radionuclides, contributing to enhanced long-term predictability of radionuclide migration in SF-OPA as potential host rock for a deep geological repository.

Influence of microstructure on hydrogen trapping and diffusion in a pre-deformed TRIP steel

Austenitic steels are known to exhibit a low hydrogen diffusion coefficient and hence a good resistance to hydrogen embrittlement. Therefore, it is an experimental challenge to investigate their hydrogen diffusion properties. In this study, the electrochemical permeation technique is used to determine the hydrogen diffusion coefficients in different pre-deformed states (φ = 0, 0.32, 0.39, 0.49) of the high-alloy austenitic TRIP steel X3CrMnNiMoN17-8-4 in a temperature range of 323 K–353 K. In combination with microstructural analysis, a correlation between phase transformation from γ-austenite to α′-martensite and dislocation density is shown. As a result of the lattice transformation from fcc to bcc, the diffusion rate of hydrogen is significantly increased (Dapp,φ = 0 = 3.6 × 10−12 cm2 s−1, Dapp, φ = 0.32 = 1.6 × 10−11 cm2 s−1at 323 K). With higher degrees of deformation, the dislocation density also increased in the martensite islands, resulting in a degressive growth of the diffusion coefficient (Dapp, φ = 0.39 = 5.3 × 10−11 cm2 s−1, Dapp, φ = 0.49 = 1.1 × 10−10 cm2 s−1at 323 K). Moreover, detailed calculations are performed to describe the way of hydrogen trapping and to give a possible mechanism of diffusion.

Efficient vertical charge transport in polycrystalline halide perovskites revealed by four-dimensional tracking of charge carriers.

Fast diffusion of charge carriers is crucial for efficient charge collection in perovskite solar cells. While lateral transient photoluminescence microscopies have been popularly used to characterize charge diffusion in perovskites, there exists a discrepancy between low diffusion coefficients measured and near-unity charge collection efficiencies achieved in practical solar cells. Here, we reveal hidden microscopic dynamics in halide perovskites through four-dimensional (directions x, y and z and time t) tracking of charge carriers by characterizing out-of-plane diffusion of charge carriers. By combining this approach with confocal microscopy, we discover a strong local heterogeneity of vertical charge diffusivities in a three-dimensional perovskite film, arising from the difference between intragrain and intergrain diffusion. We visualize that most charge carriers are efficiently transported through the direct intragrain pathways or via indirect detours through nearby areas with fast diffusion. The observed anisotropy and heterogeneity of charge carrier diffusion in perovskites rationalize their high performance as shown in real devices. Our work also foresees that further control of polycrystal growth will enable solar cells with micrometres-thick perovskites to achieve both long optical path length and efficient charge collection simultaneously.

Tobacco and Hot Pot Odor Adsorbed by Cotton, Wool, and Polyester Fabrics: Desorption Components and Dynamic Analysis

Fibrous textiles readily absorb and desorb ambient odors. However, information on the composition and dynamic analysis of tobacco smoke and hot pot odors on fabrics during desorption is limited. This study used gas chromatography–mass spectrometry to analyze the desorption components of cotton, wool, and polyester fabrics exposed to these two odors, respectively. Then, a dynamic diffusion fabric structure model demonstrated the effect of airflow velocity and fabric porosity on nicotine desorption. Furthermore, we proposed mass diffusion coefficients with different molecular weights. The results showed that cotton fabrics with tobacco smoke released many low molecular weight compounds, while with wool fabrics significantly fewer compounds were detected than for the other two fabrics. Notably, 3-ethenylpyridine, a marker of tobacco smoke, was not detected in wool fabrics. For hot pot odor, cotton fabrics released more hexanal, nonanal, and anethole than wool and polyester, while wool fabrics released many β-pinenes. The numerical results of the dynamic model showed that the air inlet velocity significantly affects the nicotine concentration in the fabric. Meanwhile, the concentration of nicotine in fabrics with lower porosity decreased faster. A lower mass diffusion coefficient will cause odors to remain in the fabric. This study aimed at the composition and the dynamics of odor in fabrics and offers essential information and simple models for reducing unnecessary washing of textiles and odor resistance textile design.

The electrochemical characterization and kinetic investigation of sub-micron Bi2Fe4O9 as possible anode of advanced lithium-ion batteries

Research in anode materials of Li-ion batteries has demonstrated an effective strategy to improve its capacity by the combination of abundant Fe as a redox center and Bi as an alloying center, which integrates the merits of Bi2O3 and Fe2O3 anodes. In this work, a novel lithium storage material Bi2Fe4O9 has been synthesized via a facile hydrothermal method. A time-dependent experiment at 160 ℃ displays that the proper reaction time is 12 h for obtaining the pure Bi2Fe4O9 sub-micron particles (SM-BFO). When applied as anode of Li-half battery, the as-prepared SM-BFO delivers a high first discharge capacity (1038.4 mAh g−1) at 0.2 A g−1, excellent cyclability (459.6 mAh g−1 after 500 cycles), good rates capability (138.9 mAh g−1 even at 5.0 A g−1), low active energy (50 kJ mol−1) and fast ion diffusion coefficient (6.9◊10−12 cm2 s−1) compared to that of the bulk counter, owing to the shorter diffusion distance. The results illustrate a great potential in advanced Li-ion batteries.

Nickel-cobalt layered double hydroxide fabricated on TiO2/C nanofiber arrays as free standing electrode for high performance supercapacitors

Nickel-cobalt layered double hydroxides (LDHs) as electrode materials have recently received intense interests. However, the low conductivity, sluggish charge transfer kinetics and poor electrolyte penetration restrict the capacitive performance and hinder their practical applications. Herein, the Ni-Co-LDH nanosheets were introduced to the core/shell structured TiO2/C nanofiber arrays (TiO2/C NFAs) to construct a free-standing composite electrode for supercapacitor through a one-step electrodeposition method. The best-performing Ni1Co1-LDH/TiO2/C NFAs electrode exhibits high specific capacitance (1717.8 F g−1 at 1 mA cm−2), remarkable rate capability with 75.1 % retention when the current density increased from 1 mA cm−2 to 75 mA cm−2, and excellent cycling stability (84.1 % of the original capacitance after 5000 cycles at 78.1 A g−1), surpassing most of the Ni-Co-LDH electrodes reported before. This excellent performance owes to the high conductivity of TiO2/C NFAs which can endow the low ohmic resistance and high diffusion coefficient of Ni-Co-LDH which may alleviate the structure degradation. Meanwhile, the Ni-Co-LDH with the optimized Ni/Co ratio of 1:1 can provide proper particle size of LDH nanosheets, small charge transfer resistance (Rct), and high stability of Ni-Co-LDH to resist the structure degradation in the long-term cycling process.

Transport barrier in 5D gyrokinetic flux-driven simulations

Two ways for producing a transport barrier through strong shear of the E × B poloidal flow have been investigated using GYSELA gyrokinetic simulations in a flux-driven regime. The first one uses an external poloidal momentum (i.e. vorticity) source that locally polarizes the plasma, and the second one enforces a locally steep density profile that also stabilizes the ion temperature gradient (ITG) instability modes linearly. Both cases show a very low local turbulent heat diffusivity coefficient and a slight increase in core pressure when a threshold of (respectively the E × B shear rate and average linear growth rate of ITG) is reached, validating previous numerical results. This pressure increase and quench are the signs of a transport barrier formation. This behaviour is the result of a reduced turbulence intensity which strongly correlates with the shearing of turbulent structures as evidenced by a reduction of the auto-correlation length of potential fluctuations as well as an intensity reduction of the k θ spectrum. Moreover, a small shift towards smaller poloidal wavenumber is observed in the vorticity source region which could be linked to a tilt of the turbulent structures in the poloidal direction.

Influences of Divalent Ions in Natural Seawater/River Water on Nanofluidic Osmotic Energy Generation.

Besides the dominant NaCl, natural seawater/river water contains trace multivalent ions, which can provide effective screening of surface charges. Here, in both negatively and positively charged nanopores, influences from divalent ions as counterions and co-ions have been investigated with respect to the performance of osmotic energy conversion (OEC) under natural salt gradients. As counterions, trace Ca2+ ions can suppress the electric power and conversion efficiency significantly. The reduced OEC performance is due to the bivalence and low diffusion coefficient of Ca2+ ions instead of the uphill transport of divalent ions discovered in the previous work. Effectively screened charged surfaces by Ca2+ ions induce an enhanced diffusion of Cl- ions which simultaneously decreases the net ion penetration and ionic selectivity of the nanopore. As co-ions, Ca2+ ions have weak effects on the OEC performance. The promotion from charged exterior surfaces in OEC processes for ultrashort nanopores is also studied, with an effective region of ∼200 nm in width beyond pore boundaries independent of the presence of Ca2+ ions. Our results shed light on the physical details of the nanofluidic OEC process under natural seawater/river water conditions, which can provide a useful guide for high-performance osmotic energy harvesting.

Effect of Carbonate Anions on the Stability of Quaternary Ammonium Groups for Aemfcs

Anion-exchange membrane fuel cells (AEMFCs) have been attracting significant attention as a promising green and effective technology for energy conversion, suitable for both automotive and stationary applications. AEMFCs operate in an alkaline environment and thus allow the use of non-precious metal electrocatalysts from a wide selection of materials, as well as lower cost anion-exchange membranes (AEMs). In spite of the significant progress recently achieved, the commercial development of AEMFCs is hampered by both AEM degradation and the carbonation processes. The chemical decomposition of the AEMs during fuel cell operation is still considered as the main challenge that needs to be addressed. The combination of high pH environment and high current densities in the AEMFCs results in hydroxide anions with limited solvation, becoming extremely reactive towards positively charged quaternary ammonium (QA) salts. This decomposition leads to detrimental reduction in anion conductivity and therefore in fuel cell performance. Understanding the carbonation process is also critical to allow AEMFCs to operate with ambient air. Hydroxide anions created in the oxygen reduction reaction react with CO2 even at low concentrations, to form bi/carbonates ions. The lower diffusion coefficients and ionic mobility of CO3 -2 and HCO3 - increases resistivity and reduces power output.In this study we experimentally show for the first time the effect of carbonation on the degradation processes of the AEM. The experimental results are compared to modeling by MD. This study provides insights into the carbonation effect on cation stability in alkaline systems, which has significant implications for the final stability of AEMs resulting in long term operation of AEMFCs under real ambient air conditions.

Effect of halophilic bacteria on reducing chloride-ion concentration in mortars

• A new biological mortar was developed to enhance the salt damage resistance. • Halophilic bacteria were used for decomposing chloride compounds in concrete. • Halomonas venusta is favorable for reducing the chloride-ion concentration. • We confirmed that the activity of bacteria in the hardened cement matrix. • We verified the potential of the developed mortar as a biomimetic material. The present pioneering study examines the significance and limitations of biological mortars originally developed to enhance the salt damage resistance of concrete. Three strains of halophilic bacterium are isolated considering the decomposition mechanism of bacteria for chloride compounds in the cement matrix, thereby reducing the chloride ion concentration in the mortar. Test results showed that Halomonas venusta exhibited a good potential in reducing the chloride-ion concentration in mortars exposed to salt attacks, indicating a lower chloride-ion diffusion coefficient and lower amounts of Friedel’s salt by consuming the chloride ions as an energy source for its activity and growth.

Examining the Role of Magnetic Resonance Imaging (MRI) in Cerebral Ischemic Stroke: A Cross-Sectional Study

Objective: The aim of this study is to examine the role of Magnetic Resonance Imaging (MRI) when detecting cerebral ischemic stroke. Study design: A cross-sectional study Place and Duration: This study was conducted at Sandeman Provincial Hospital/ Bolan medical complex hospital Quetta, Quetta from March 2021 to March 2022 Methodology: Age and gender distribution of infarcts was done to find out the territory and location of the blood vessels involved. Overall, 52 individuals were involved in this research. Every patient was clinically suspected to have a cerebral ischemic stroke during the time span of our research. HDXT software with 1.5 Tesla 16 channel GE was used to perform the MRI scans. FLAIR axial, T1WI axial, T2WI axial and coronal, ADC maps, and gradient echo axial were the sequences used. SWI was optional. Results: The age group which was above 60 years included more percentage of males than females. It was seen that in the age group above 60 years, infarction was the most common and hypertension was the most common risk factor. Hemiplegia (Weakness) was seen to be the most common clinical presentation. It was seen that middle cerebral artery (MCA) territory infarcts had a slight rise on the right side. On the diffusion-weighted imaging (DWI), restricted diffusion was seen from subacute as well as acute infarcts along with a low apparent diffusion coefficient (ADC)valves. T2 FLAIR was normal in acute infarcts, but changes were reflected by DWI. Practical implication : Expanding the rationale for acute stroke thrombolysis may be more rationally accomplished by comprehending the clinical implications of numerous valuable MRI findings and thoroughly incorporating those factors into treatment decision-making. Conclusion: No radiation hazard is seen in MRI and it is non-invasive. The multiplanar imaging ability and grey-white resolution of the MRI perceive the subtle lesions. Infarcts are detected early due to the sensitivity of MRI to altered water content. Keywords: magnetic resonance imaging, stroke, cerebral infarcts,

The Effect of Sintering Time on Electronic Conductivity of LiFeGdPO4/C as a Lithium-Ion Battery Cathode

Lithium iron phosphate (LiFePO4) is an alternative cathode material choice in lithium-ion batteries because of its non-toxic nature, high voltage (3.45 V), the high theoretical capacity of LiFePO4 (170 mAh/g), low cost, non-reactive and has good structural properties stability. However, LiFePO4 has a low electronic conductivity (10-9-10-10 S/cm) and a low diffusion coefficient of Li+ ions (10-12-10-14 cm2/s), so it affects electrochemical performance. There are several ways to increase the conductivity. These are namely carbon coating, metal ion doping and optimizing the sintering time. Optimal sintering time will increase crystallinity, thereby increasing the value of electronic conductivity. Then using the right sintering time will get a lot of the desired phase content. This study aims to determine the effect of the sintering time variation 6 hours, 8 hours, 10 hours, 20 hours and 30 hours to increase the electronic conductivity of LiFeGdPO4/C. The synthesis method used is the carbothermal reduction method with the precursors used are LiH2PO4, Fe2O3, Gd2O3 and carbon graphite. LCR meter and XRD are used to characterize samples. The results obtained indicate that the effect of sintering time can increase the value of the electronic conductivity of LiFeGdPO4/C, with the highest conductivity value at a sintering time of 30 hours of 1.5296 x 10-7 S/cm.