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1.
Environ Res ; 258: 119404, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38880323

RESUMO

Adsorption is a promising way to remove persistent organic pollutants (POPs), a major environmental issue. With their high porosity and vast surface areas, MOFs are suited for POP removal due to their excellent adsorption capabilities. This review addresses the intricate principles of MOF-mediated adsorption and helps to future attempts to mitigate organic water pollution. This review examines the complicated concepts of MOF-mediated adsorption, including MOF synthesis methodologies, adsorption mechanisms, and material tunability and adaptability. MOFs' ability to adsorb POPs via electrostatic forces, acid-base interactions, hydrogen bonds, and pi-pi interactions is elaborated. This review demonstrates its versatility in eliminating many types of contaminants. Functionalizing, adding metal nanoparticles, or changing MOFs after they are created can improve their performance and remove contaminants. This paper also discusses MOF-based pollutant removal issues and future prospects, including adsorption capacity, selectivity, scale-up for practical application, stability, and recovery. These obstacles can be overcome by rationally designing MOFs, developing composite materials, and improving material production and characterization. Overall, MOF technology research and innovation hold considerable promise for environmental pollution solutions and sustainable remediation. Desorption and regeneration in MOFs are also included in the review, along with methods for improving pollutant removal efficiency and sustainability. Case studies of effective MOF regeneration and scaling up for practical deployment are discussed, along with future ideas for addressing these hurdles.

2.
Sensors (Basel) ; 22(12)2022 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-35746336

RESUMO

Throughout service, damage can arise in the structure of buildings; hence, their dynamic testing becomes essential to verify that such buildings possess sufficient strength to withstand disturbances, particularly in the event of an earthquake. Dynamic testing, being uneconomical, requires proof of concept; for this, a model of a structure can be dynamically tested, and the results are used to update its finite element model. This can be used for damage detection in the prototype and aids in predicting its behavior during an earthquake. In this instance, a wireless MEMS accelerometer was used, which can measure the vibration signals emanating from the building and transfer these signals to a remote workstation. The base of the structure is excited using a shaking table to induce an earthquake-like situation. Four natural frequencies have been considered and six different types of damage conditions have been identified in this work. For each damage condition, the experimental responses are measured and the finite element model is updated using the Berman and Nagy method. It is seen that the updated models can predict the dynamic responses of the building accurately. Thus, depending on these responses, the damage condition can be identified by using the updated finite element models.


Assuntos
Terremotos , Vibração , Análise de Elementos Finitos
3.
Sensors (Basel) ; 22(2)2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-35062478

RESUMO

Fused deposition modelling (FDM)-based 3D printing is a trending technology in the era of Industry 4.0 that manufactures products in layer-by-layer form. It shows remarkable benefits such as rapid prototyping, cost-effectiveness, flexibility, and a sustainable manufacturing approach. Along with such advantages, a few defects occur in FDM products during the printing stage. Diagnosing defects occurring during 3D printing is a challenging task. Proper data acquisition and monitoring systems need to be developed for effective fault diagnosis. In this paper, the authors proposed a low-cost multi-sensor data acquisition system (DAQ) for detecting various faults in 3D printed products. The data acquisition system was developed using an Arduino micro-controller that collects real-time multi-sensor signals using vibration, current, and sound sensors. The different types of fault conditions are referred to introduce various defects in 3D products to analyze the effect of the fault conditions on the captured sensor data. Time and frequency domain analyses were performed on captured data to create feature vectors by selecting the chi-square method, and the most significant features were selected to train the CNN model. The K-means cluster algorithm was used for data clustering purposes, and the bell curve or normal distribution curve was used to define individual sensor threshold values under normal conditions. The CNN model was used to classify the normal and fault condition data, which gave an accuracy of around 94%, by evaluating the model performance based on recall, precision, and F1 score.

4.
Environ Monit Assess ; 194(8): 576, 2022 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-35821153

RESUMO

Natural and anthropogenic pollution influence the general hydrochemistry of freshwater sources. Effective management strategies need an accurate evaluation of the water quality parameters, and inferences extracted from the data should be based on the most appropriate statistical methods. Conventional water quality indices (WQI) being related to a large number of water quality parameters results in significant variability and analytical costs. The focus of this study was to develop a remodeled water quality index (WQImin) based on the localized trends in water quality and demonstrate it to understand water quality variations of Dal Lake (a freshwater lake in the Himalayan region). Spatio-temporal changes and trends of 14 water quality parameters were investigated that were arbitrated from the samples collected at 11 sampling locations during the water quality monitoring across the Dal Lake from September 2017 to August 2020. The results signify that the general mean WQI value was 81.9, and seasonal average WQI values ranges from 79.44 to 84.55. The water quality showed seasonal variance, with lowest values in summer, succeeded by autumn and winter, and highest in spring. Moreover, the results from stepwise multiple regression analysis indicated that the WQImin significantly correlates with six water quality parameters (ammonia, dissolved oxygen, chemical oxygen demand, temperature, turbidity, and nitrate) in Dal Lake. The WQImin model predicted the water quality of the Dal Lake with a coefficient of determination (R2) value of 0.96, root mean square error (RMSE) value of 4.1, and percentage error (PE) of 5.3%. The developed WQImin model can be applied as a cost-effective and efficacious approach to determine the water quality of fresh surface water bodies.


Assuntos
Lagos , Qualidade da Água , Monitoramento Ambiental/métodos , Nitratos , Estações do Ano
5.
Environ Res ; 180: 108857, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31727340

RESUMO

Heterostructured α-Bismuth zinc oxide (α-Bi2O3-ZnO) photocatalyst was fabricated by a facile and cost-effective, ultrasound assisted chemical precipitation method followed by hydrothermal growth technique. As synthesized α-Bi2O3-ZnO photocatalyst showed enhanced photocatalytic performance for the MB dye degradation in contrast to pure ZnO and α-Bi2O3. Light emitting diodes (UV-LED) were used in the experimental setup, which has several advantages over conventional lamps like wavelength selectivity, high efficacy, less power consumption, long lifespan, no disposal problem, no warming-up time, compactness, easy and economic installation. XRD study confirmed the presence of both the lattice phases i.e. monoclinic and hexagonal wurtzite phase corresponding to α-Bi2O3 and ZnO in the α-Bi2O3-ZnO composite photocatalyst. FESEM images showed that α-Bi2O3-ZnO photocatalyst is composed of dumbbell like structures of ZnO with breadth ranging 4-5 µm and length ranging from 10 to 11 µm respectively. It was observed that α-Bi2O3 nanoparticles were attached on the ZnO surface and were in contact with each other. Low recombination rate of photo-induced electron-hole pairs, due to the migration of electrons and holes between the photocatalyst could be responsible for the 100% photocatalytic efficiency of α-Bi2O3-ZnO composite. In addition, photocatalyst was also observed to show the excellent antimicrobial activity with 1.5 cm zone of inhibition for 1 mg L-1 dose, against the human pathogenic bacteria (S. aureus).


Assuntos
Anti-Infecciosos , Azul de Metileno , Óxido de Zinco , Bismuto , Catálise , Staphylococcus aureus , Zinco
6.
Technol Soc ; 62: 101305, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32834232

RESUMO

Indeed, the scientific milestones set by the ever-emerging three-dimensional printing (3DP) technologies are tremendous. Till now, the innovative 3DP technologies have benefitted the aerospace, automobile, textile, pharmaceutical, and biomedical sectors by developing pre-requisite designed and customized performance standards of the end-user products. As the scientific world, at this moment, is expediting efforts to fight against the highly damaging novel coronavirus (COVID-19) pandemic, the 3DP technologies are facilitating creative solutions in terms of personal protective equipment (PPE), medical equipment (such as ventilators and other respiratory devices), and other health and welfare tools to aid the personal hygiene as well as safe environment for humans by restricting the communication of risks. Various sources (including journal articles, news articles, white papers of the government and other non-profit organizations, commercial enterprises, as well as academic institutions have been reviewed for the collection of the information relevant to COVID-19 and 3DP. This communication presents the recent applications of the 3DP technologies aiding in developing innovative products designed to save the lives of millions of people around the world. Moreover, the potential of 3DP technologies in developing test swabs and controlled medicines has been highlighted. The literature reviewed in the present study indicated that the fused filament fabrication (FFF) is one of the most preferred technologies and contribute about 62% in the overall production of the protective gears developed through overall class of 3DP.

7.
Neurol India ; 67(1): 163-168, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30860117

RESUMO

PURPOSE: Long standing temporal lobe epilepsy (TLE) causes cerebral insult and results in elevated brain injury biomarkers, S100b and neuron specific enolase (NSE). Surgery for TLE, has the potential to cause additional cerebral insult. Dexmedetomidine is postulated to have neuroprotective effects. The aim of this study was to assess the effect of intraoperative dexmedetomidine on S100b and NSE during TLE surgery. MATERIALS AND METHODS: 19 consenting adult patients with TLE undergoing anteromedial temporal lobectomy were enrolled and divided into two groups. Patients in Group D (n = 9) received dexmedetomidine whereas patients in Group C (n = 10) received saline as placebo in addition to the standard anaesthesia technique. Blood samples of these patients were drawn, before induction of anaesthesia, at the end of surgery, as well at 24 hours and 48 hours postoperatively, and analysed for serum S100b and NSE. RESULTS: The demographic and clinical profile was comparable in both the groups. The baseline S100b in group C and group D was 66.7 ± 26.5 pg/ml and 34.3 ± 21.7 pg/ml (P = 0.013) respectively. After adjustment for the baseline, the overall value of S100b was 71.0 ± 39.8 pg/ml and 40.5 ± 22.5 pg/ml (P = 0.002) in the control and study group, respectively. The values of S100b (79.3 ± 53.6 pg/ml) [P = 0.017] were highest at 24 hours postoperatively. The mean value of NSE in the control and study group was 32.8 ± 43.4 ng/ml (log 3.0 ± 0.1) and 13.51 ± 9.12 ng/ml (log 2.42 ± 0.60), respectively. The value of NSE in both the groups was comparable at different time points. CONCLUSIONS: Lower perioperative values of S100b were observed in patients who received intraoperative dexmedetomidine. Dexmedetomidine may play a role in cerebroprotection during epilepsy surgery.


Assuntos
Dexmedetomidina/uso terapêutico , Epilepsia do Lobo Temporal/cirurgia , Fármacos Neuroprotetores/uso terapêutico , Procedimentos Neurocirúrgicos/métodos , Adolescente , Adulto , Biomarcadores/sangue , Método Duplo-Cego , Epilepsia do Lobo Temporal/sangue , Feminino , Humanos , Masculino , Fosfopiruvato Hidratase/sangue , Subunidade beta da Proteína Ligante de Cálcio S100/sangue , Resultado do Tratamento , Adulto Jovem
8.
Work ; 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38640184

RESUMO

BACKGROUND: Textile-sizing mill workers are exposed to various hazards in the sizing units during their working hours and are at risk of acquiring lung impairments due to the usage of sizing chemicals in the sizing process. OBJECTIVE: The main aim of this study is to assess the influence of cotton dust and sizing agents on lung function and breathing difficulties among Indian textile sizing mill workers. METHODS: This cross-sectional study was carried out at a textile-sizing mill from August 2022 to September 2022. A modified questionnaire based American Thoracic Society's standard was used to assess respiratory symptoms among sizing mill workers and the pulmonary function test was conducted Spirometry. The chi-square test was used to find the difference between respiratory symptoms and the t-test was used to find the difference between spirometric parameters. RESULTS: Textile sizing mill workers showed significant (P <  0.0001) decline in peak expiratory flow rate, forced vital capacity (FVC), ratio of FEV1 and forced vital capacity, and forced expiratory volume in 1 s (FEV1). There was an association between symptoms and duration of exposure to pulmonary abnormality. Sizing mill workers showed a significant decline in lung functions and an increase in pulmonary symptoms. As the service duration of exposure in terms of years increased, respiratory symptoms increased and spirometric abnormality also increased. CONCLUSION: This study confirms that sizing agents such as polyvinyl alcohol (PVA), emulsifier, wax, carboxymethyl cellulose (CMC), and starch used in sizing mills are also responsible for respiratory illness and lung impairment among textile workers.

9.
Sci Rep ; 14(1): 15453, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38965308

RESUMO

Present study has been conducted to characterize the Mg alloy namely AZ31-based composite joined by Friction stir processing (FSP) technique. This study deals with the effect of single and double passes in FSP of AZ31 Mg alloy. The single pass run in FSP is followed at tool rotation speed (N) of 1000 to 1400 rpm. Also, the double pass run in FSP was followed at these speeds without using reinforcements. The feedstock particles namely SiC, Al2O3, Cr, and Si powders were used in fabrication process. The hardness, impact strength, and tensile strength characteristics were assessed in the stir region zone, and the results indicated significant improvement in these properties. The highest values of mechanical strength were seen in the FSPed area with N = 1000 rpm at a constant transverse speed (r) of 40 mm/min. Also, the tensile strength of the two passes FSPed plates is much higher than that of the single section without any reinforcement, as revealed in previous study also. The Scanning electron microscopy (SEM) analysis is done at two different magnifications for the Silicon carbide, Alumina, Chromium, and Silicon powder reinforced composites fabricated at speed of 1000 rpm. The microstructure shows that reinforced particles were uniform dispersed into FSPed region and agglomerated with Mg matrix. Si powder produces finer microstructure as compare to SiC, Al2O3, Cr. FSP decreases the grain size of processed material. Optical Microscopy results revealed that the reinforcement particle produced a homogenous microstructure and, a refined grain and equally dispersed in matrix material without split to the particle.

10.
Indian J Orthop ; 58(6): 705-715, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38812869

RESUMO

Objectives: The acetabular cup design plays a critical role in reducing contact stress between femur head acetabular cup. Many studies used ellipsoidal and spheroidal geometry in acetabular cup design to effectively reduce contact stress. The present study focuses on elevated acetabular cup rim with round corner design to reduce contact stress with round corner geometry. Methods: The cobalt chromium femur head and cup are considered for finite element (FE) model of hip resurfacing. The gait loads of routine activities of humans like normal walking, stair ascending and descending and sitting down and getting up gait activities are applied to the developed 3D FE model. Five microseparations of 0.5, 1, 1.5, 2 and 2.5 mm are considered in the present study. The acetabular cup inclination angle considered for this study are 35°, 45°, 55°, 65° and 75°. The contact stress and von Mises stress plot for each gait activities under these microseparations are analyzed for betterment of longevity of implants. Results: Overall elevated cup rim design helped in reducing contact stress to a greater extent than conventional cup with different geometries. Also, the predicted von Mises stress for all the parameters considered in the current study are well within the yield strength of CoCr material. Therefore, elevated cup rim could be used as a better alternative to spline and, ellipsoidal and circular geometries of cup.

11.
Int J Biol Macromol ; 277(Pt 1): 133816, 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-39002911

RESUMO

Diabetic vascular complication including diabetic retinopathy is a major morbidity in Saudia Arabia. The polyol pathway aka aldose reductase (AR) pathway has gained significant association with diabetic retinopathy with regard to chronically enhanced glucose metabolism. Considerable research has been put forth to develop more effective therapeutic strategies to overcome the overwhelming challenges of vascular complications associated with diabetes. In this regard, constituents of Cichorium intybus can offer strong AR inhibitory potential because of their strong antidiabetic properties. Therefore, aim of this study was to investigate the AR inhibitory as well as antiglycation potential of C. intybus extract/compounds. The preliminary in vitro results showed that methanolic extract of C. intybus could significantly inhibit AR enzyme and advanced glycation end product formation. Eventually, based on previous studies and reviews, we selected one hundred fifteen C. intybus root constituents and screened them through Lipinski's rule of five and ADMET analysis. Later, after molecular docking analysis of eight compounds, five best were selected for molecular dynamics simulation to deduce their binding affinity with the AR enzyme. Finally, three out of five compounds were further tested in vitro for their AR inhibitory potential and antiglycation properties. Enzyme assay and kinetic studies showed that all the three tested compounds were having potent AR inhibitory properties, although to a lesser extent than ellagic acid and tolrestat. Similarly, kaempferol showed strong antiglycation property equivalent to ellagic acid, but greater than aminoguanidine. Intriguingly, significant reduction in sorbitol accumulation in RBCs by the tested compounds substantiated strong AR inhibition by these compounds. Moreover, decrease in sorbitol accumulation under high glucose environment also signifies the potential application of these compounds in diabetic retinopathy and other vascular complications. Thus, in sum, the in silico and in vitro studies combinedly showed that C. intybus root is a treasure for therapeutic compounds and can be explored further for drug development against diabetic retinopathy.

12.
Heliyon ; 10(12): e32210, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38975212

RESUMO

Control of a bioprocess is a challenging task mainly due to the nonlinearity of the process, the complex nature of microorganisms, and variations in critical parameters such as temperature, pH, and agitator speed. Generally, the optimum values chosen for critical parameters during Escherichia coli (E.coli) K-12fed-batch fermentation are37 ᵒC for temperature, 7 for pH, and 35 % for Dissolved Oxygen (DO). The objective of this research is to enhance biomass concentration while minimizing energy consumption. To achieve this, an Event-Triggered Control (ETC) scheme based on feedback-feed forward control is proposed. The ETC system dynamically adjusts the substrate feed rate in response to variations in critical parameters. We compare the performance of classical Proportional Integral (PI) controllers and advanced Model Predictive Control (MPC) controllers in terms of bioprocess yield. Initially, the data are collected from a laboratory-scaled 3L bioreactor setup under fed-batch operating conditions, and data-driven models are developed using system identification techniques. Then, classical Proportional Integral (PI) and advanced Model Predictive Control (MPC) based feedback controllers are developed for controlling the yield of bioprocess by manipulating substrate flow rate, and their performances are compared. PI and MPC-based Event Triggered Feed Forward Controllers are designed to increase the yield and to suppress the effect of known disturbances due to critical parameters. Whenever there is a variation in the value of a critical parameter, it is considered an event, and ETC initiates a control action by manipulating the substrate feed rate. PI and MPC-based ETC controllers are developed in simulation, and their closed-loop performances are compared. It is observed that the Integral Square Error (ISE) is notably minimized to 4.668 for MPC with disturbance and 4.742 for MPC with Feed Forward Control. Similarly, the Integral Absolute Error (IAE) reduces to 2.453 for MPC with disturbance and 0.8124 for MPC with Feed Forward Control. The simulation results reveal that the MPC-based ETC control scheme enhances the biomass yield by 7 %, and this result is verified experimentally. This system dynamically adjusts the substrate feed rate in response to variations in critical parameters, which is a novel approach in the field of bioprocess control. Also, the proposed control schemes help reduce the frequency of communication between controller and actuator, which reduces power consumption.

13.
ACS Omega ; 9(16): 17878-17890, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38680352

RESUMO

Aluminum metal cast composites (AMCCs) are frequently used in high-tech sectors such as automobiles, aerospace, biomedical, electronics, and others to fabricate precise and especially responsible parts. The mechanical and wear behavior of the metal matrix composites (MMCs) is anticipated to be influenced by the cooling agent's action and the cooling temperature. This research paper presents the findings of a series of tests to investigate the mechanical, wear, and fracture behavior of hybrid MMCs made of Al7075 reinforced by varying wt % of nano-sized Al2O3 and Gr and quenched with water and ice cubes. The heat-treated Al7075 alloy hybrid composites were evaluated for their hardness, tensile, and wear behavior, showcasing a significant process innovation. The heat treatment process greatly improved the hybrid composites' mechanical and wear performance. The samples quenched in ice attained the highest hardness of 119 VHN. There is a 45.37% improvement in the hardness of base alloy with the addition of 3% of Al2O3 and 1% of graphite particles. Further, the highest tensile and compression strengths were found in the ice-quenched 3% Al2O3 and 1% graphite hybrid composites with improvements of 34.2 and 48.83%, respectively, compared to the water-quenched base alloy. Under the samples quenched in ice, the mechanical and wear behavior improved. The tensile fractured surface showed voids, particle pullouts, and dimples. The worn-out surface of wear test samples of the created hybrid composite had micro pits, delamination layers, and microcracks.

14.
Adv Healthc Mater ; : e2401525, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38978444

RESUMO

Lung cancer remains a major global health concern with high mortality rates and poor prognosis. Bridging the gap between the chemical and cellular understanding of cell-decorated biomimetic nanocomposites and their clinical translation is crucial for developing effective therapies. Nanocomposites show promise in targeted drug delivery and diagnostics, but their clinical application is hindered by biocompatibility and clearance issues. To overcome these challenges, biomimetic approaches utilizing cell membrane-coated nanomaterials emerge. By camouflaging nanomaterials with cell membranes, the biointerfaces are enhanced, and the inherent properties of the donor cell membranes are acquired. This review provides an overview of recent advancements on cell membrane-coated nanocomposites for lung cancer diagnosis and treatment. It discusses fabrication techniques, biomedical applications, challenges, and future prospects. The incorporation of cell membranes into nanocomposites holds potential for improved lung cancer therapy, but further development and refinement are needed for precise tumor targeting. Addressing the identified challenges will pave the way for clinical translation of these biomimetic nanoplatforms and advance lung cancer diagnosis and treatment.

15.
Sci Rep ; 14(1): 16293, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-39009787

RESUMO

In the present work, we report on theoretical studies of thermodynamic properties, structural and dynamic stabilities, dependence of unit-cell parameters and elastic constants upon hydrostatic pressure, charge carrier effective masses, electronic and optical properties, contributions of interband transitions in the Brillouin zone of the novel Tl2HgGeSe4 crystal. The theoretical calculations within the framework of the density-functional perturbation theory (DFPT) are carried out employing different approaches to gain the best correspondence to the experimental data. The present theoretical data indicate the dynamical stability of the title crystal and they reveal that, under hydrostatic pressure, it is much more compressible along the a-axis than along the c-axis. Strikingly, the charge effective mass values ( m e ∗ and m h ∗ ) vary considerably when the high symmetry direction changes indicating a relative anisotropy of the charge-carrier's mobility. Furthermore, the Young modulus and compressibility are characterized by the maximum and minimum values ( E max and E min ) and ( ß max and ß min ) that are equal to (62.032 and 28.812) GPa and (13.672 and 6.7175) TPa-1, respectively. Additionally, we have performed calculations of the Raman spectra (RS) and reached a good correspondence with the experimental RS spectra of the Tl2HgGeSe4 crystal. The XPES associated to RS constitutes powerful techniques to explore the oxidized states of Se and Ge in Tl2HgGeSe4 system.

16.
Chemosphere ; 323: 138233, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36863626

RESUMO

The diverse nature of polymers with attractive properties has replaced the conventional materials with polymeric composites. The present study was sought to evaluate the wear performance of thermoplastic-based composites under the conditions of different loads and sliding speeds. In the present study, nine different composites were developed by using low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polyethylene terephthalate (PET) with partial sand replacements i.e., 0, 30, 40, and 50 wt%. The abrasive wear was evaluated as per the ASTM G65 standard test for abrasive wear through a dry-sand rubber wheel apparatus under the applied loads of 34.335, 56.898, 68.719, 79.461 and 90.742 (N) and sliding speeds of 0.5388, 0.7184, 0.8980, 1.0776 and 1.4369 (m/s). The optimum density and compressive strength were obtained to be 2.0555 g/cm3 and 46.20 N/mm2, respectively for the composites HDPE60 and HDPE50 respectively. The minimum value of abrasive wear were found to 0.02498, 0.03430, 0.03095, 0.09020 and 0.03267 (cm3) under the considered loads of 34.335, 56.898, 68.719, 79.461 and 90.742 (N), respectively. Moreover, the composites LDPE50, LDPE100, LDPE100, LDPE50PET20 and LDPE60 showed a minimum abrasive wear of 0.03267, 0.05949, 0.05949, 0.03095 and 0.10292 at the sliding speeds of 0.5388, 0.7184, 0.8980, 1.0776 and 1.4369 (m/s), respectively. The wear response varied non-linearly with the conditions of loads and sliding speeds. Micro-cutting, plastic deformations, fiber peelings, etc. were included as the possible wear mechanism. The possible correlations between wear and mechanical properties, and throughout discussions for wear behaviors through the morphological analyses of the worn-out surfaces were provided.


Assuntos
Plásticos , Areia , Dióxido de Silício , Teste de Materiais , Polímeros , Polietileno
17.
Nanomaterials (Basel) ; 13(10)2023 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-37242000

RESUMO

This paper proposes two different approaches to studying resistive switching of oxide thin films using scratching probe nanolithography of atomic force microscopy (AFM). These approaches allow us to assess the effects of memristor size and top-contact thickness on resistive switching. For that purpose, we investigated scratching probe nanolithography regimes using the Taguchi method, which is known as a reliable method for improving the reliability of the result. The AFM parameters, including normal load, scratch distance, probe speed, and probe direction, are optimized on the photoresist thin film by the Taguchi method. As a result, the pinholes with diameter ranged from 25.4 ± 2.2 nm to 85.1 ± 6.3 nm, and the groove array with a depth of 40.5 ± 3.7 nm and a roughness at the bottom of less than a few nanometers was formed. Then, based on the Si/TiN/ZnO/photoresist structures, we fabricated and investigated memristors with different spot sizes and TiN top contact thickness. As a result, the HRS/LRS ratio, USET, and ILRS are well controlled for a memristor size from 27 nm to 83 nm and ranged from ~8 to ~128, from 1.4 ± 0.1 V to 1.8 ± 0.2 V, and from (1.7 ± 0.2) × 10-10 A to (4.2 ± 0.6) × 10-9 A, respectively. Furthermore, the HRS/LRS ratio and USET are well controlled at a TiN top contact thickness from 8.3 ± 1.1 nm to 32.4 ± 4.2 nm and ranged from ~22 to ~188 and from 1.15 ± 0.05 V to 1.62 ± 0.06 V, respectively. The results can be used in the engineering and manufacturing of memristive structures for neuromorphic applications of brain-inspired artificial intelligence systems.

18.
Natl J Maxillofac Surg ; 13(Suppl 1): S225-S227, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36393934

RESUMO

Pleomorphic adenoma is the most common salivary gland tumor which accounts for about 60% of all salivary neoplasms. It is also known as "mixed tumor because of its wide cytomorphologic diversity". Pleomorphic adenoma salivary glands mostly occurs on the palate, but the involvement of the upper lip is rare. The present report describes a case of a 62-year-old male with asymptomatic firm nodular swelling attached with upper lip which was later diagnosed as pleomorphic adenoma in the excisional biopsy.

19.
Materials (Basel) ; 15(20)2022 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-36295410

RESUMO

Structural adhesives have shown significant improvements in their behavior over the past few decades [...].

20.
Materials (Basel) ; 15(15)2022 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-35897591

RESUMO

The feasibility of producing welding joints between 6061-T6 aluminum and pure copper sheets of 6 mm thickness by conventional friction stir welding (CFSW) and bobbin tool friction stir welding (BTFSW) by using a slot-groove configuration at the joining surface was investigated. The microstructure of the welded samples was examined by using an optical microscope and X-ray diffraction. Furthermore, the mechanical properties of the weld samples are compared based on the results of the tensile test, hardness measurement, and fractography test. The slot-groove configuration resulted in the presence of a bulk-sized Al block on the Cu side. The microscopic observations revealed the dispersion of fine Cu particles in the stir zone. The presence of intermetallic compounds (IMCs) CuAl2, which are hard and brittle, lowered the strength of the weld joints. The strength of the weld joints produced with BTFSW was superior to that of the C-FSW. The maximum hardness values of 214 HV and 211 HV are reported at the stir zone for BTFSW and CFSW, respectively. The fracture location of all the joints was at the intersection of the stir zone and the thermomechanically affected zone was on the Cu side.

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