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1.
Chem Rec ; 24(4): e202300352, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38501854

RESUMEN

Recently, carbon neutrality has been promoted as a potentially practical solution to global CO2 emissions and increasing energy-consumption challenges. Many attempts have been made to remove CO2 from the environment to address climate change and rising sea levels owing to anthropogenic CO2 emissions. Herein, membrane technology is proposed as a suitable solution for carbon neutrality. This review aims to comprehensively evaluate the currently available scientific research on membranes for carbon capture, focusing on innovative microporous material membranes used for CO2 separation and considering their material, chemical, and physical characteristics and permeability factors. Membranes from such materials comprise metal-organic frameworks, zeolites, silica, porous organic frameworks, and microporous polymers. The critical obstacles related to membrane design, growth, and CO2 capture and usage processes are summarized to establish novel membranes and strategies and accelerate their scaleup.

2.
Br J Nurs ; 33(14): S30-SIV, 2024 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-39023027

RESUMEN

PURPOSE: This study aimed to determine the incidence of peripheral intravenous catheter (PIVC)-induced phlebitis and its predictors among adult patients hospitalized at Dow University Hospital, Karachi, Pakistan. METHODS: A sample of 258 adult patients admitted in the selected wards and planned for peripheral intravenous catheter insertion were recruited through consecutive sampling during March to May 2019. Daily follow-ups were performed to observe signs of phlebitis using a validated tool. The cohort was followed until discharge, removal of peripheral intravenous catheter, or study conclusion. RESULTS: Of 258 patients studied, 139 (53.9%) were females. A significant number of the participants 104 (40.3%) were young adults of age 20-40 years. The incidence of phlebitis was 39.1%. Tuberculosis (TB), peripheral intravenous catheter dwell time before initial assessment, administration of IV fluids, and dissatisfactory nursing care at Day 1 were associated significantly with the development of phlebitis. There was a doseresponse relationship between the catheter dwell time in hours before initial assessment and the development of phlebitis. CONCLUSION: This study found an increased incidence (39.1%) in three months of PIVC-induced phlebitis among adult patients. In addition to patient-related and PIVC-related risk factors considered in this study, PIVC-induced phlebitis is found to be significantly associated with the level of PIVC care provided by nurses. Continuous nursing education, developing standard care plans for PIVCs, and proper documentation of care are recommended.


Asunto(s)
Cateterismo Periférico , Flebitis , Centros de Atención Terciaria , Humanos , Flebitis/epidemiología , Flebitis/etiología , Femenino , Adulto , Masculino , Cateterismo Periférico/efectos adversos , Pakistán/epidemiología , Incidencia , Estudios de Cohortes , Factores de Riesgo , Adulto Joven , Persona de Mediana Edad
3.
Gut ; 73(1): 186-202, 2023 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-37734912

RESUMEN

Smart capsules are developing at a tremendous pace with a promise to become effective clinical tools for the diagnosis and monitoring of gut health. This field emerged in the early 2000s with a successful translation of an endoscopic capsule from laboratory prototype to a commercially viable clinical device. Recently, this field has accelerated and expanded into various domains beyond imaging, including the measurement of gut physiological parameters such as temperature, pH, pressure and gas sensing, and the development of sampling devices for better insight into gut health. In this review, the status of smart capsules for sensing gut parameters is presented to provide a broad picture of these state-of-the-art devices while focusing on the technical and clinical challenges the devices need to overcome to realise their value in clinical settings. Smart capsules are developed to perform sensing operations throughout the length of the gut to better understand the body's response under various conditions. Furthermore, the prospects of such sensing devices are discussed that might help readers, especially health practitioners, to adapt to this inevitable transformation in healthcare. As a compliment to gut sensing smart capsules, significant amount of effort has been put into the development of robotic capsules to collect tissue biopsy and gut microbiota samples to perform in-depth analysis after capsule retrieval which will be a game changer for gut health diagnosis, and this advancement is also covered in this review. The expansion of smart capsules to robotic capsules for gut microbiota collection has opened new avenues for research with a great promise to revolutionise human health diagnosis, monitoring and intervention.


Asunto(s)
Biopsia , Tracto Gastrointestinal , Robótica , Humanos , Endoscopía Capsular , Microbioma Gastrointestinal
4.
Chin J Traumatol ; 2023 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-37517923

RESUMEN

Injuries deeper than the platysma are considered as penetrating neck injuries, constituting approximately 5% - 10% of all trauma. Many vital organs are at risk from a penetrating neck injury. These injuries in zone 1 have the highest mortality, because the injuries are close to the vital organs and difficult to access surgically. A 41-year-old male, a car mechanic by profession, presented to the emergency department with a penetrating neck injury on the right side. CT scan demonstrated a metallic foreign body in zone 1 between the right internal jugular vein and the common carotid artery. The patient was asymptomatic, and the foreign body was removed surgically. This case shows a rare presentation of a penetrating neck injury with a foreign body located in zone 1, where no vital internal structure was injured. As of now, no previous case report has been identified on such presentation. Thus, it will provide a valuable addition to the pre-existing literature.

5.
Sensors (Basel) ; 22(9)2022 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-35591190

RESUMEN

This paper presents a multi-axis low-cost soft magnetic tactile sensor with a high force range for force feedback in robotic surgical systems. The proposed sensor is designed to fully decouple the output response for normal, shear and angular forces. The proposed sensor is fabricated using rapid prototyping techniques and utilizes Neodymium magnets embedded in an elastomer over Hall sensors such that their displacement produces a voltage change that can be used to calculate the applied force. The initial spacing between the magnets and the Hall sensors is optimized to achieve a large displacement range using finite element method (FEM) simulations. The experimental characterization of the proposed sensor is performed for applied force in normal, shear and 45° angular direction. The force sensitivity of the proposed sensor in normal, shear and angular directions is 16 mV/N, 30 mV/N and 81 mV/N, respectively, with minimum mechanical crosstalk. The force range for the normal, shear and angular direction is obtained as 0-20 N, 0-3.5 N and 0-1.5 N, respectively. The proposed sensor shows a perfectly linear behavior and a low hysteresis error of 8.3%, making it suitable for tactile sensing and biomedical applications. The effect of the material properties of the elastomer on force ranges and sensitivity values of the proposed sensor is also discussed.


Asunto(s)
Procedimientos Quirúrgicos Robotizados , Elastómeros , Retroalimentación , Fenómenos Magnéticos , Fenómenos Mecánicos
6.
J Pak Med Assoc ; 66(3): 256-9, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26968272

RESUMEN

OBJECTIVE: To determine the difference in analgesic requirement in terms of mean postoperative narcotic consumption and mean postoperative pain score in patients undergoing unilateral inguinal hernia repair with or without bupivacaine infiltration as day-care patients. METHODS: The randomised controlled trial was conducted at Aga Khan University Hospital, Karachi, from June to December 2011, and comprised patients who were randomly divided into groups A and B. Tramadol 1.5 mgkg-1 was used as intraoperative analgesia. At the time of closure of surgical incision, 20ml of bupivacaine 0.25% plain was infiltrated in the subcutaneous tissue sub-facially and in the deeper layers along the incision line in patients of group A. In group B, which was the control group, the surgical wound was closed without infiltrating bupivacaine. On arrival in post-anaesthesia care unit, the patient's pain scores was assessed using Visual Analogue Scale every 15 minutes for the first hour, every 30 minutes for next one hour, and hourly for the next two hours by a blinded observer. Postoperative narcotic consumption was also noted. RESULTS: There were 80 patients in the study; 40(50%) in each of the two groups. Mean postoperative narcotic consumption and mean pain scores were high in group B in all follow-ups (up to 4 hours) compared to group A patients (p<0.05). CONCLUSIONS: Wound infiltration with 0.25% bupivacaine diminished post-operative pain and decreased narcotic analgesic consumption for the first four hours after unilateral inguinal hernia repair.


Asunto(s)
Analgésicos Opioides/uso terapéutico , Anestésicos Locales/uso terapéutico , Bupivacaína/uso terapéutico , Hernia Inguinal/cirugía , Herniorrafia , Dolor Postoperatorio/prevención & control , Tramadol/uso terapéutico , Adulto , Anciano , Procedimientos Quirúrgicos Ambulatorios , Anestesia Local , Método Doble Ciego , Procedimientos Quirúrgicos Electivos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Dimensión del Dolor , Dolor Postoperatorio/tratamiento farmacológico , Adulto Joven
7.
BMC Genet ; 16: 8, 2015 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-25643626

RESUMEN

BACKGROUND: Little is known about the role of amino acids in cellular signaling pathways, especially as it pertains to pathways that regulate the rate of aging. However, it has been shown that methionine or tryptophan restriction extends lifespan in higher eukaryotes and increased proline or tryptophan levels increase longevity in C. elegans. In addition, leucine strongly activates the TOR signaling pathway, which when inhibited increases lifespan. RESULTS: Therefore each of the 20 proteogenic amino acids was individually supplemented to C. elegans and the effects on lifespan were determined. All amino acids except phenylalanine and aspartate extended lifespan at least to a small extent at one or more of the 3 concentrations tested with serine and proline showing the largest effects. 11 of the amino acids were less potent at higher doses, while 5 even decreased lifespan. Serine, proline, or histidine-mediated lifespan extension was greatly inhibited in eat-2 worms, a model of dietary restriction, in daf-16/FOXO, sir-2.1, rsks-1 (ribosomal S6 kinase), gcn-2, and aak-2 (AMPK) longevity pathway mutants, and in bec-1 autophagy-defective knockdown worms. 8 of 10 longevity-promoting amino acids tested activated a SKN-1/Nrf2 reporter strain, while serine and histidine were the only amino acids from those to activate a hypoxia-inducible factor (HIF-1) reporter strain. Thermotolerance was increased by proline or tryptophan supplementation, while tryptophan-mediated lifespan extension was independent of DAF-16/FOXO and SKN-1/Nrf2 signaling, but tryptophan and several related pyridine-containing compounds induced the mitochondrial unfolded protein response and an ER stress response. High glucose levels or mutations affecting electron transport chain (ETC) function inhibited amino acid-mediated lifespan extension suggesting that metabolism plays an important role. Providing many other cellular metabolites to C. elegans also increased longevity suggesting that anaplerosis of tricarboxylic acid (TCA) cycle substrates likely plays a role in lifespan extension. CONCLUSIONS: Supplementation of C. elegans with 18 of the 20 individual amino acids extended lifespan, but lifespan often decreased with increasing concentration suggesting hormesis. Lifespan extension appears to be caused by altered mitochondrial TCA cycle metabolism and respiratory substrate utilization resulting in the activation of the DAF-16/FOXO and SKN-1/Nrf2 stress response pathways.


Asunto(s)
Aminoácidos/química , Caenorhabditis elegans/fisiología , Longevidad , Aminoácidos/administración & dosificación , Animales , Autofagia , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Unión al ADN/genética , Dieta , Complejo I de Transporte de Electrón/genética , Complejo II de Transporte de Electrones/genética , Estrés del Retículo Endoplásmico , Factores de Transcripción Forkhead/metabolismo , Respuesta al Choque Térmico , Mitocondrias/metabolismo , Modelos Animales , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
8.
J Pak Med Assoc ; 65(8): 895-7, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26228341

RESUMEN

Interferon-alpha, a potent mediator of host immune response, has immunomodulatory properties in addition to its antiviral effects. A wide spectrum of autoimmune diseases can occur in patients treated with interferon-alpha for chronic hepatitis B and D, of which clinical systemic lupus erythematosus (SLE) accounts for less than 1% and hypothyroidism for 2-4 %. We report herein a case of a 16-year-old male who developed antinuclear antibody (ANA)-negative SLE and hypothyroidism after treatment with interferon-alpha for chronic hepatitis. High index of suspicion is therefore necessary in all patients treated with interferon for early diagnosis and treatment.


Asunto(s)
Antivirales/efectos adversos , Hepatitis B Crónica/tratamiento farmacológico , Hepatitis D Crónica/tratamiento farmacológico , Hipotiroidismo/inducido químicamente , Interferón-alfa/efectos adversos , Lupus Eritematoso Sistémico/inducido químicamente , Adolescente , Humanos , Masculino
9.
ISA Trans ; 149: 26-43, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38719682

RESUMEN

This paper studies the control problem for a continuous-time networked system with non-linearity in the state equation as well as in the input, as saturation. The system is considered under denial-of-service (DoS), attacks which cause the blockage of input and/or output components in the overall closed-loop model. An event-triggering scheme that is resilient in nature, along with an observer-based control, has been considered under DoS attacks. The resultant scheme ensures efficient network resources and excludes Zeno behavior naturally due to the presence of a minimum positive interevent delay. Then, an event-based switched non-linear model is presented to address both the event-triggering scheme and the presence of DoS blocking attacks. A piece-wise Lyapunov-Krasovskii functional method on the described non-linear model, resulting in the switched system, is considered for achieving an exponentially stable response by driving the required feasibility conditions. In the presence of a non-linear system with saturation in the actuator, the presented design establishes quantitative relationships among the exponential decay rate, active/sleeping intervals of attacks, parameters of the event-triggering condition, and sampling period of the system. After that, linear matrix inequalities are presented for designing an event-triggered controller with an observer, while the design also includes the region of convergence for dealing with the input non-linearity. Finally, comparative results for an offshore structure model with non-linearity in states as well as in actuator, are demonstrated to verify the results of the control scheme that is developed. It has been verified that our design is less conservative than the previous designs, and can handle the non-linearities in the dynamics of plant and actuator saturation more efficiently, while DoS attacks are also present. By applying our proposed method, the overshoot and undershoot are less than ±2.5 percent, while system states converge to the origin within 55 s.

10.
ISA Trans ; 148: 128-139, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38433069

RESUMEN

This paper considers an output feedback consensus control approach for the generic linear multi-agent systems (MASs) under input saturation over a directed graph. A region of stability-based approach has been established for dealing with the input saturation. A conventional Luenberger observer for estimating the states of followers by themselves and an advanced cooperative observer for estimating the state of leader by followers have been applied for an estimated state feedback control. The stability conditions have been derived by considering a three-term-based combined Lyapunov function. Moreover, computationally simple controller and estimator design conditions have been obtained by resorting to a decoupling approach A set of initial conditions has been investigated to achieve the leader-following consensus of MASs under the input saturation constraint. To the best of our knowledge, an output feedback consensus approach, providing a consensus region, for generic linear MASs under input saturation over directed graphs without requiring the exact state of the leader has been explored for the first time. In contrast to the existing methods, the proposed approach considers an output feedback approach (rather than the state feedback), accounts for both linear and nonlinear saturation regions, applies an estimate of the state of the leader through cooperative observer, and is based on a generalized sector condition for the saturation nonlinearity. In addition, it offers a computationally simple design solution owing to the proposed decoupling method. Simulation results are provided to validate the efficacy of the designed protocol for F-18 aircraft and unmanned ground vehicles.

11.
Biology (Basel) ; 13(5)2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38785823

RESUMEN

Estimating the population density of vulnerable species, such as the elusive and nocturnal Asiatic black bear (Ursus thibetanus), is essential for wildlife conservation and management. We used camera traps and a Random Encounter Model (REM) to estimate the population density of U. thibetanus during the autumn and winter seasons in the Hindu Raj Mountains. We installed 23 camera traps from October to December 2020 and acquired 66 independent pictures of Asiatic black bears over 428 trap nights. Our results showed that the bears preferred lowland areas with the presence of Quercus spp. We estimated, using the REM, a population density of U. thibetanus of 1.875 (standard error = 0.185) per square kilometer, which is significantly higher than that in other habitats. Our results showed that during autumn and winter, the bear population density tends to concentrate at lower elevations. Forest cover showed a positive correlation with the rates of bear encounters unlike the Euclidean distance to human settlements, altitude, and aspect variables. The approaches used here are cost-effective for estimating the population density of rare and vulnerable species such as U. thibetanus, and can be used to estimate their population density in Pakistan. Population density estimation can identify areas where the bears live and human-bear conflicts occurred and use this information in future wildlife management plans.

12.
J Burn Care Res ; 45(2): 398-403, 2024 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-37879628

RESUMEN

High-pressure cylinders are used to store liquefied petroleum gas (LPG). An instant and swift explosion of these cylinders can result in serious burn injuries. This current research was conducted to study the epidemiological characteristics of LPG-related burns to highlight a major public health issue. Analysis was conducted on patients with LPG-related burns over a span of 10 years admitted to our center between January 2011 and December 2020. The data recorded included demographic features, site of burn, %TBSA, associated injuries, and outcomes. The variable data were documented for every patient in a Microsoft Excel file and analyzed by IBM SPSS version 25.0. Over the span of 10 years, 678 patients were affected by LPG-related accidents. The peak incidence was seen in 2019 when there was a surge to 18.03%. The patient's age ranged from 1 to 79 years, with a median of 40.86 ± 15.27 years. Of the 678 patients, 52.50% were males and 47.50% were females. The majority (57.96%) of patients had a total BSA of >60% and 86.72% were diagnosed with inhalation injury. The majority of burns (84.66%) occurred at home. The mean hospital stay was 24.5 days. The total mortality rate was 59.58%. This study concludes that LPG cylinder blast is a preventable cause that can be minimized by making people aware of its safe use and by arranging awareness programs at every national level.


Asunto(s)
Quemaduras , Petróleo , Masculino , Femenino , Humanos , Lactante , Preescolar , Niño , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , Anciano , Quemaduras/epidemiología , Quemaduras/terapia , Quemaduras/etiología , Unidades de Quemados , Hospitalización , Tiempo de Internación , Estudios Retrospectivos
13.
J Burn Care Res ; 2024 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-38894616

RESUMEN

Seasons have a major impact on the frequency and characteristics of burn injuries; in warmer months, thermal burns from outdoor activities are more common, while in cooler months, incidents involving heating sources and fires are more common. It is essential to comprehend these trends in order to customise safety precautions and awareness initiatives. Studies on the impact of seasonal variations help burn centres allocate resources more effectively in order to prepare for variations in patient volume and severity. Data from January 2016 to December 2022, with an emphasis on burn types excluding non-burn cases, were analysed retrospectively over a seven-year period at the Burn Care Centre in PIMS, Islamabad. The research examined hospital stays, demographics, burn causes, admissions, total burned surface area, and death rates while dividing the years into winter and summer seasons for analysis. With 4,014 admitted patients, the study found that winter admissions increased by 11.007%, with winter admissions accounting for 55.503% of all admissions and summer admissions for 44.496%. The gender distribution stayed the same, with 54.59% of the population being male and 45.99% being female. Hospital stays were longer for summer admissions (16.428) than for winter admissions (11.285). Summertime saw a rise in electric burn cases (307 cases), with a 43 case fatality rate. With 1699 cases, flame burns predominated in the epidemiology of burns, followed by scald burns with 1384 cases. In conclusion, seasonal differences have a substantial impact on burn profiles, with winter seeing a marked rise in occurrences. Men are also more likely to sustain electric burns, particularly in the summer. Effective management and prevention techniques depend on an understanding of these patterns.

14.
J Burn Care Res ; 2024 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-38602154

RESUMEN

Severe burn injuries pose diagnostic challenges, contributing to increased fatality rates with delayed diagnoses. This study aims to identify early risk factors and understand their impact on clinical outcomes by examining hematological dynamics in severe burn cases. The focus includes age-related patterns, Total Body Surface Area (TBSA) affected by burns, hospital stay duration, and changes in hematological markers during burn injuries. An analytical cross-sectional study at the Burn Care Centre involved 135 participants hospitalized between January 2018 and December 2021. Demographic data and hematological markers were recorded, with statistical analysis using IBM SPSS 25.0. Non-survivors exhibited a greater mean TBSA, shorter hospital stay, and an enhanced early immune response indicated by WBC count on the first day. Hematological markers, including HGB, RCC, and PLT, showed dynamic patterns over the study period. Marginal variations in platelet counts and intriguing patterns in RCC suggested potential consequences like disseminated intravascular coagulation. The study provides crucial insights into hematological responses to severe burn injuries. Early identification of risk factors, particularly age-related patterns and immune responses, informs clinicians about predicting outcomes and guiding therapeutic interventions. Despite limitations, this work underscores the need for further multi-center research to comprehensively understand the complex relationships between burn injuries, hematological responses, and clinical outcomes.

15.
RSC Adv ; 14(22): 15571-15581, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38746840

RESUMEN

Transparent and conductive electrodes (TCEs) are essential for various optoelectronic and photovoltaic applications, but they often require expensive and complex fabrication methods. In this paper, a unique low-cost, eco-friendly, and scalable method of fabricating TCEs using spray-coated carbon ink is investigated. Firstly the carbon particles used for this process underwent a size reduction from 20 microns to 0.96 microns via ball milling. Then ink was prepared by mixing graphite powder (for conductivity), ethyl cellulose (for viscosity), and toluene (for solubility) with different weight-per-volume ratios (w/v) of 5%, 10%, and 15%. The TCEs were fabricated by spray coating the ink onto glass substrates using an airbrush. The sheet resistance (Ω sq-1) and transparency (%) of the TCEs were measured by a digital multimeter (DMM) probe method and a UV-vis spectrophotometer, respectively. The sheet resistance of the TCEs decreased linearly from 60 to 20 Ω sq-1, while the transparency decreased exponentially from 37.18% to 18.88% as the ink concentration increased from 5% to 15% w/v. This paper also reports the reflectance and absorbance values for each ink concentration. The results demonstrate that spray-coated carbon ink TCEs achieve sheet resistance and transparency values of 20 Ω sq-1 and 18.88%, respectively, with low-cost and eco-friendly materials and methods, which are desirable for optoelectronic and photovoltaic applications. These TCEs can play an important role as electrodes in semi-transparent perovskite cells enhancing their stability and overall efficiency.

16.
ISA Trans ; 137: 74-86, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36588059

RESUMEN

This article proposes the design of a distributed state estimator for a class of one-sided Lipschitz nonlinear systems over wireless sensor networks. The suggested estimation scheme utilizes the one-sided Lipschitz constraint in conjunction with quadratic inner-boundedness, which makes it applicable to a broader class of nonlinear systems. The proposed estimator design is evaluated under a conventional event-triggered mechanism both in the absence and presence of external perturbations. Furthermore, a novel event-triggering condition is introduced that ensures error convergence to the origin in the absence of external perturbations. It is further established that the inclusion of new triggering condition reduces the estimation error upper bounds in the presence of external disturbances and noises. Sufficient conditions for boundedness of estimation errors are derived for each case, and matrix inequalities are developed for the calculation of estimator gains. Finally, a numerical example is considered to illustrate the efficacy of the proposed estimator.

17.
Environ Sci Pollut Res Int ; 30(33): 81267-81287, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37314557

RESUMEN

Recently, there has been a lot of focus on global trade and consumption-based carbon (CCO2) emissions. More research, however, has examined how financial development (FD) and international trade in renewable energy affect CO2 emissions. Furthermore, there are no distinct trends in the research about how globalization affects environmental quality. Our research analyzes and empirically investigates the relationship between CCO2 emissions and renewable energy, FD, and trade. A large panel of data from 41 G20 and European Union (EU) countries is assembled for empirical analysis from 1990 to 2019. The practical outcomes of panel quantile regression and feasible generalized least square (FGLS) approaches display that renewable energy and FD positively relate to CCO2 emissions; furthermore, trade to GDP hurts CCO2 emissions; market classification has been taken as a control variable which shows that the developed countries released more carbon than non-developed countries. These results suggest that the financial sector focuses more on supporting companies that use ecologically friendly techniques and pushing them to use other energy well-organized technologies in their production processes. As a result, CCO2 emissions will be reduced, preventing environmental damage at the non-renewable energy plant.


Asunto(s)
Carbono , Comercio , Unión Europea , Desarrollo Económico , Internacionalidad , Dióxido de Carbono
18.
ISA Trans ; 137: 98-110, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36801138

RESUMEN

This paper discusses a leader-following consensus problem for nonlinear multi-agent systems (MASs) subjected to generalized Lipschitz-type nonlinearity using output feedback. An event-triggered (ET) leader-following control scheme, based upon estimated states using observers, is proposed for efficient bandwidth utilization by application of invariant sets. Distributed observers are designed to estimate the states of the followers because actual states are not always readily available. Besides, in order to reduce unnecessary data communication among the followers, an ET strategy has been formulated which excludes Zeno behavior as well. Under this proposed scheme, sufficient conditions are formulated using Lyapunov theory. These conditions not only guarantee the asymptotic stability of estimation error, but also ensure the tracking consensus of nonlinear MASs. Further, a simple and less conservative design approach using a decoupling scheme for assuring necessity and sufficiency for the main design approach has also been explored. The decoupling scheme is similar to separation principle for linear systems. Contrary to the existing works, the nonlinear systems considered in this study cover a wide family of Lipschitz nonlinearities, including both globally and locally Lipschitz systems. Moreover, the proposed approach is more efficient in handling ET consensus. Finally, the obtained results are verified with single link robots and modified Chua's circuits.

19.
IEEE Trans Cybern ; 53(1): 55-66, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34280113

RESUMEN

In this article, the group consensus problem is addressed for a network of multiagent systems (MASs). Unlike in existing literature, where a relative-state feedback-based distributed control input is used to achieve group consensus, this work aims at designing a relative-output-based distributed control law to achieve the same goal. To that effect, the Lyapunov stability theory is used to formulate the sufficient and necessary conditions for the existence of such a feedback controller and then separate conditions have been included for its design. In addition to that, a new linear matrix inequality is explored to choose the intracluster coupling strengths to ensure group consensus. In this article, the relative-output-based control approach is investigated for both the leaderless and the leader-following frameworks of the group consensus problem, and the theoretical findings presented are validated using numerical examples and simulation results.

20.
PLoS One ; 18(4): e0283734, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37040363

RESUMEN

This paper proposes a static anti-windup compensator (AWC) design methodology for the locally Lipschitz nonlinear systems, containing time-varying interval delays in input and output of the system in the presence of actuator saturation. Static AWC design is proposed for the systems by considering a delay-range-dependent methodology to consider less conservative delay bounds. The approach has been developed by utilizing an improved Lyapunov-Krasovskii functional, locally Lipschitz nonlinearity property, delay-interval, delay derivative upper bound, local sector condition, L2 gain reduction from exogenous input to exogenous output, improved Wirtinger inequality, additive time-varying delays, and convex optimization algorithms to obtain convex conditions for AWC gain calculations. In contrast to the existing results, the present work considers both input and output delays for the AWC design (along with their combined additive effect) and deals with a more generic locally Lipschitz class of nonlinear systems. The effectiveness of the proposed methodology is demonstrated via simulations for a nonlinear DC servo motor system, possessing multiple time-delays, dynamic nonlinearity and actuator constraints.


Asunto(s)
Redes Neurales de la Computación , Percepción del Tiempo , Algoritmos
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