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1.
Sports Med Open ; 10(1): 36, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38600291

RESUMO

BACKGROUND: Daily nutrition plays an important role in supporting training adaptions and endurance performance. The objective of this 10-week study was to investigate the consequences of varying carbohydrate consumption and the glycaemic index (GI) together with an endurance training regimen on substrate oxidation, muscle energy storage and endurance performance under free-living conditions. Sixty-five moderately trained healthy men (29 ± 4 years; VO2 peak 55 ± 8 mL min-1 kg-1) were randomized to one of three different nutritional regimes (LOW-GI: 50-60% CHO with ≥ 65% of these CHO with GI < 50 per day, n = 24; HIGH-GI: 50-60% CHO with ≥ 65% CHO with GI > 70 per day, n = 20; LCHF: ≤ 50 g CHO daily, n = 21). Metabolic alterations and performance were assessed at baseline (T0) and after 10 weeks (T10) during a graded exercise treadmill test. Additionally, a 5 km time trial on a 400-m outdoor track was performed and muscle glycogen was measured by magnet resonance spectroscopy. RESULTS: Total fat oxidation expressed as area under the curve (AUC) during the graded exercise test increased in LCHF (1.3 ± 2.4 g min-1 × km h-1, p < 0.001), remained unchanged in LOW-GI (p > 0.05) and decreased in HIGH-GI (- 1.7 ± 1.5 g min-1 × km h-1, p < 0.001). After the intervention, LOW-GI (- 0.4 ± 0.5 mmol L-1 × km h-1, p < 0.001) and LCHF (- 0.8 ± 0.7 mmol L-1 × km h-1, p < 0.001) showed significantly lower AUC of blood lactate concentrations. Peak running speed increased in LOW-GI (T0: 4.3 ± 0.4 vs. T10: 4.5 ± 0.3 m s-1, p < 0.001) and HIGH-GI (T0: 4.4 ± 0.5 vs. T10: 4.6 ± 0.4 m s-1), while no improvement was observed in LCHF. Yet, time trial performance improved significantly in all groups. Muscle glycogen content increased for participants in HIGH-GI (T0: 97.3 ± 18.5 vs. T10: 144.5 ± 39.8 mmol L wet-tissue-1, p = 0.027) and remained unchanged in the LOW-GI and the LCHF group. At the last examination, muscle glycogen concentration was significantly higher in LOW-GI compared to LCHF (p = 0.014). CONCLUSION: Changes in fat oxidation were only present in LCHF, however, lower lactate concentrations in LOW-GI resulted in changes indicating an improved substrate metabolism. Compared to a LCHF diet, changes in peak running speed, and muscle glycogen stores were superior in LOW- and HIGH-GI diets. The low GI diet seems to have an influence on substrate metabolism without compromising performance at higher intensities, suggesting that a high-carbohydrate diet with a low GI is a viable alternative to a LCHF or a high GI diet. TRIAL REGISTRATION: Clinical Trials, NCT05241730. https://clinicaltrials.gov/study/NCT05241730 . Registered 25 January 2021.

2.
Diabetologia ; 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38656372

RESUMO

AIMS/HYPOTHESIS: Obesity surgery (OS) and diet-induced weight loss rapidly improve insulin resistance. We aim to investigate the impact of either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) surgery compared with a diet low in energy (low-calorie diet; LCD) on body composition, glucose control and insulin sensitivity, assessed both at the global and tissue-specific level in individuals with obesity but not diabetes. METHODS: In this parallel group randomised controlled trial, patients on a waiting list for OS were randomised (no blinding, sealed envelopes) to either undergo surgery directly or undergo an LCD before surgery. At baseline and 4 weeks after surgery (n=15, 11 RYGB and 4 SG) or 4 weeks after the start of LCD (n=9), investigations were carried out, including an OGTT and hyperinsulinaemic-euglycaemic clamps during which concomitant simultaneous whole-body [18F]fluorodeoxyglucose-positron emission tomography (PET)/MRI was performed. The primary outcome was HOMA-IR change. RESULTS: One month after bariatric surgery and initiation of LCD, both treatments induced similar reductions in body weight (mean ± SD: -7.7±1.4 kg and -7.4±2.2 kg, respectively), adipose tissue volume (7%) and liver fat content (2% units). HOMA-IR, a main endpoint, was significantly reduced following OS (-26.3% [95% CI -49.5, -3.0], p=0.009) and non-significantly following LCD (-20.9% [95% CI -58.2, 16.5). For both groups, there were similar reductions in triglycerides and LDL-cholesterol. Fasting plasma glucose and insulin were also significantly reduced only following OS. There was an increase in glucose AUC in response to an OGTT in the OS group (by 20%) but not in the LCD group. During hyperinsulinaemia, only the OS group showed a significantly increased PET-derived glucose uptake rate in skeletal muscle but a reduced uptake in the heart and abdominal adipose tissue. Both liver and brain glucose uptake rates were unchanged after surgery or LCD. Whole-body glucose disposal and endogenous glucose production were not significantly affected. CONCLUSIONS/INTERPRETATION: The short-term metabolic effects seen 4 weeks after OS are not explained by loss of body fat alone. Thus OS, but not LCD, led to reductions in fasting plasma glucose and insulin resistance as well as to distinct changes in insulin-stimulated glucose fluxes to different tissues. Such effects may contribute to the prevention or reversal of type 2 diabetes following OS. Moreover, the full effects on whole-body insulin resistance and plasma glucose require a longer time than 4 weeks. TRIAL REGISTRATION: ClinicalTrials.gov NCT02988011 FUNDING: This work was supported by AstraZeneca R&D, the Swedish Diabetes Foundation, the European Union's Horizon Europe Research project PAS GRAS, the European Commission via the Marie Sklodowska Curie Innovative Training Network TREATMENT, EXODIAB, the Family Ernfors Foundation, the P.O. Zetterling Foundation, Novo Nordisk Foundation, the Agnes and Mac Rudberg Foundation and the Uppsala University Hospital ALF grants.

3.
Artigo em Inglês | MEDLINE | ID: mdl-38656402

RESUMO

The combination of shikonin (SKN) and gefitinib (GFB) can reverse the drug resistance of lung cancer cells by affecting energy metabolism. However, the poor solubility of SKN and GFB limits their clinical application because of low bioavailability. Wheat germ agglutinin (WGA) can selectively bind to sialic acid and N-acetylglucosamine on the surfaces of microfold cells and enterocytes, and is a targeted biocompatible material. Therefore, we created a co-delivery micelle system called SKN/GFB@WGA-micelles with the intestinal targeting functions to enhance the oral absorption of SKN and GFB by promoting mucus penetration for nanoparticles via oral administration. In this study, Caco-2/HT29-MTX-E12 co-cultured cells were used to simulate a mucus/enterocyte dual-barrier environment, and HCC827/GR cells were used as a model of drug-resistant lung cancer. We aimed to evaluate the oral bioavailability and anti-tumor effect of SKN and GFB using the SKN/GFB@WGA-micelles system. In vitro and in vivo experimental results showed that WGA promoted the mucus penetration ability of micelles, significantly enhanced the uptake efficiency of enterocytes, improved the oral bioavailability of SKN and GFB, and exhibited good anti-tumor effects by reversing drug resistance. The SKN/GFB@WGA-micelles were stable in the gastrointestinal tract and provided a novel safe and effective drug delivery strategy.

4.
Angew Chem Int Ed Engl ; : e202406937, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38656692

RESUMO

Polymers are ideally utilized as damping materials due to the high internal friction of molecular chains, enabling effective suppression of vibrations and noises in various fields. Current strategies rely on broadening the glass transition region or introducing additional relaxation components to enhance the energy dissipation capacity of polymeric damping materials. However, it remains a significant challenge to achieve high damping efficiency through structural control while maintaining dynamic characteristics.  In this work, we propose a new strategy to develop hyperbranched vitrimers (HBVs) containing dense pendant chains and loose dynamic crosslinked networks. A novel yet weak dynamic transesterification between the carboxyl and boronic acid ester was confirmed and used to prepare HBVs based on poly (hexyl methacrylate-2-(4-ethenylphenyl)-5,5-dimethyl-1,3,2-dioxaborinane) P(HMA-co-ViCL) copolymers. The ABn-type of macromonomers, the crosslinking points formed by the dynamic covalent connection via the associative exchange, and the weak yet dynamic exchange reaction are the three keys to developing high-performance HBV damping materials. We found that P(HMA-co-ViCL) 20k-40-60 HBV exhibited ultrahigh energy-dissipation performance over a broad frequency and temperature range, attributed to the synergistic effect of dense pendant chains and weak dynamic covalent crosslinks. This unique design concept will provide a general approach to developing advanced damping materials.

5.
Med Biol Eng Comput ; 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38656734

RESUMO

This paper proposes a medical image fusion method in the non-subsampled shearlet transform (NSST) domain to combine a gray-scale image with the respective pseudo-color image obtained through different imaging modalities. The proposed method applies a novel improved dual-channel pulse-coupled neural network (IDPCNN) model to fuse the high-pass sub-images, whereas the Prewitt operator is combined with maximum regional energy (MRE) to construct the fused low-pass sub-image. First, the gray-scale image and luminance of the pseudo-color image are decomposed using NSST to find the respective sub-images. Second, the low-pass sub-images are fused by the Prewitt operator and MRE-based rule. Third, the proposed IDPCNN is utilized to get the fused high-pass sub-images from the respective high-pass sub-images. Fourth, the luminance of the fused image is obtained by applying inverse NSST on the fused sub-images, which is combined with the chrominance components of the pseudo-color image to construct the fused image. A total of 28 diverse medical image pairs, 11 existing methods, and nine objective metrics are used in the experiment. Qualitative and quantitative fusion results show that the proposed method is competitive with and even outpaces some of the existing medical fusion approaches. It is also shown that the proposed method efficiently combines two gray-scale images.

6.
J Environ Manage ; 358: 120941, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38663083

RESUMO

China's double carbon target aims to improve human well-being and sustainable development. Energy transformation welfare performance (ETWP) is the efficiency of energy transition (ET) in enhancing human well-being. ETWP considers both human well-being and sustainable development. Research on its driving force is helpful in achieving the double carbon goal. Thus, this paper used Logarithmic Mean Divisia Index Model, Fixed Panel Regression Model and Grey Relational Analysis Model to analyze China's ETWP from 2006 to 2022 and predicted ETWP of 31 provinces from 2023 to 2030. The results showed that: (1) ETWP had two rising periods in 2006-2014 and 2015-2022. (2) The government's rationalization policy on energy and environment and technological innovation ability were fundamental driving forces for improving ETWP. (3) There were obvious spatial and temporal distinctions in ETWP, and it would bring out different degrees in most areas. Thus, ET should be promoted by improving the ecological environment and resource utilization efficiency; The importance of the role of scientific and technological innovation and policies should be focused on in promoting ETWP; ET policies based on local developments should be formulated and the energy structure should be changed.

7.
J Colloid Interface Sci ; 667: 640-649, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38663279

RESUMO

Conventional piezoelectric nanogenerators (PNGs) face challenges in terms of degradation and reusability, which have negative environmental implications. On the other hand, biocompatible and degradable piezoelectric materials often exhibit lower piezoelectric response. In this study, potassium sodium niobate (KNN) powder and the biodegradable polymer poly(ε-caprolactone) (PCL) were used to fabricate piezoelectric composite films through solution casting. By constructing staggered electrodes, the total polarized charges quantity is increased, achieving a larger current output. The three-unit PNG (3-PNG) based on the composite film with 15 wt% KNN powder, reaches a maximum output current of 0.85 µA, which exhibits higher charging efficiency compared to 1-PNG. Moreover, the prepared 3-PNG can effectively harvest mechanical energy from human activities and maintain a stable output after 10,000 cycles of bending and releasing. The film exhibits complete degradation when exposed to acidic, neutral, and alkaline solutions. This research provides a promising option for environmentally friendly piezoelectric materials selected and output performance enhanced through optimized structural designs, making them more suitable for practical applications.

8.
Artigo em Inglês | MEDLINE | ID: mdl-38663420

RESUMO

We investigated the band renormalization caused by the compressive-strain-induced lattice mismatch in parallel AA stacked bilayer graphene using two complementary methods: the tight-binding approach and the low-energy continuum theory. While a large mismatch does not alter the low-energy bands, a small one reduces the bandwidth of the low-energy bands along with a decrease in the Fermi velocity. In the tiny-mismatch regime, the low-energy continuum theory reveals that the long-period moir'e pattern extensively renormalizes the low-energy bands, resulting in a significant reduction of bandwidth. Meanwhile, the Fermi velocity exhibits an oscillatory behavior and approaches zero at specific mismatches. However, the resulting low-energy bands are not perfectly isolated flat, as seen in twisted bilayer graphene at magic angles. These findings provide a deeper understanding of moiré physics and offer valuable guidance for related experimental studies in creating moir'e superlattices using two-dimensional van der Waals heterostructures.

9.
Bioinspir Biomim ; 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38663427

RESUMO

Inspired by the vibrations of aquatic plants such as seaweed in the unsteady flow fields generated by free-surface waves, we investigate a novel device based on piezoelectric plates to harvest energy from oscillatory cross flows. Towards this end, numerical studies are conducted using a flow-structure-electric interaction model to understand the underlying physical mechanisms involved in the dynamics and energy harvesting performance of one or a pair of piezoelectric plates in an oscillatory cross flow. In a single-plate configuration, both periodic and irregular responses have been observed depending on parameters such as normalized plate stiffness and Keulegan-Carpenter number. Large power harvesting is achieved with the excitation of natural modes. Besides, when the time scale of the motion and the intrinsic time scale of the circuit are close to each other the power extraction is enhanced. In a two-plate configuration with tandem formation, the hydrodynamic interaction between the two plates can induce irregularity in the response. In terms of energy harvesting, two counteracting mechanisms have been identified, shielding and energy recovery. The shielding effect reduces plate motion and energy harvesting, whereas with the energy recovery effect one plate is able to recovery energy from the wake of another for performance enhancement. The competition between these mechanisms leads to constructive or destructive interactions between the two plates. These results suggest that for better performance the system should be excited at its natural period, which should be close to the intrinsic time scale of the circuit. Moreover, using a pair of plates in a tandem formation can further improve the energy harvesting capacity when conditions for constructive interaction are satisfied.

10.
Pharmacol Res ; : 107194, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38663526

RESUMO

Antibiotic related intestinal injury in early life affects subsequent health and susceptibility. Here, we employed weaned piglets as a model to investigate the protective effects of baicalin against early-life antibiotic exposure-induced microbial dysbiosis. Piglets exposed to lincomycin showed a marked reduction in body weight (p < 0.05) and deterioration of jejunum intestinal morphology, alongside an increase in antibiotic-resistant bacteria such as Staphylococcus, Dolosicoccus, Escherichia-Shigella, and Raoultella. In contrast, baicalin treatment resulted in body weights, intestinal morphology, and microbial profiles that closely resembled those of the control group (p > 0.05), with a significant increase in norank_f_Muribaculaceae and Prevotellaceae_NK3B31_group colonization compared with lincomycin group (p < 0.05). Further analysis through fecal microbial transplantation into mice revealed that lincomycin exposure led to significant alterations in intestinal morphology and microbial composition, notably increasing harmful microbes and decreasing beneficial ones such as norank_Muribaculaceae and Akkermansia (p < 0.05). This shift was associated with an increase in harmful metabolites and disruption of the calcium signaling pathway gene expression. Conversely, baicalin supplementation not only counteracted these effects but also enhanced beneficial metabolites and regulated genes within the MAPK signaling pathway (MAP3K11, MAP4K2, MAPK7, MAPK13) and calcium channel proteins (ORA13, CACNA1S, CACNA1F and CACNG8), suggesting a mechanism through which baicalin mitigates antibiotic-induced intestinal and microbial disturbances. These findings highlight baicalin's potential as a plant extract-based intervention for preventing antibiotic-related intestinal injury and offer new targets for therapeutic strategies.

11.
Sci Total Environ ; : 172737, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38663611

RESUMO

Microplastic (MP) pollution has obtained severe concern due to its harmful effect on human beings and ecosystems. Existing MP removal methods face many obstacles, such as high cost, high energy consumption, low efficiency, release of toxic chemicals, etc. Thus, it is crucial to find appropriate and sustainable methods to replace common MP removal approaches. Bio-electrochemical system (BES) is a sustainable clean energy technology that has been successfully applied to wastewater treatment, seawater desalination, metal removal, energy production, biosensors, etc. However, research reports on BES technology to eliminate MP pollution are limited. This paper reviews initiatives in the mechanism, hazards, and common treatment method of MP removal and discusses the application of BES systems to improve the MPs removal efficiency and sustainability. Firstly, the characteristics and limitations of common MP removal techniques are systematically summarized. Then, the potential application of BES technology in MP removal application is explored. Furthermore, the feasibility, stability, and recommendations for further research are critically evaluated.

12.
Adv Mater ; : e2401359, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38663867

RESUMO

With the continuous upsurge in demand for wearable energy, nanogenerators are increasingly required to operate under extreme environmental conditions. Even though they are at the cutting edge of technology, nanogenerators have difficulty producing high-quality electrical output at very extreme temperatures. Here, a triboelectric basalt textile (TBT) with an ultra-wide operational temperature range (-196 to 520 °C) was created employing basalt material as the main body. The output power density of the TBT, in contrast to most conventional nanogenerators, would counterintuitively rise by 2.3 times to 740.6 mW m-2 after heating to 100 °C because the high temperature will enhance the material's interface polarization and electronic kinetic energy. The TBT retains around 55% of its initial electrical output even after heating in the flame of an alcohol lamp (520 °C). Surprisingly, the TBT's output voltage may retain over 85% of its initial value even after submerging in liquid nitrogen. The TBT's exceptional resistance to heat and cold indicates its possible use in high and low latitudes, high altitudes, deserts, and even space settings. This article is protected by copyright. All rights reserved.

13.
J Sci Med Sport ; 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38664149

RESUMO

OBJECTIVES: This was a pilot study that examined the relationship between nutrition knowledge and risk for low energy availability (LEA) in NCAA athletes. METHODS: Athletes (64.4 % female, 35.6 % male) completed the Abridged Nutrition for Sport Knowledge Questionnaire (A-NSKQ) and either the Low Energy Availability in Females Questionnaire (LEAF-Q) or Male Athlete Triad (MAT) screening questions. RESULTS: Females at risk for LEA had higher nutrition knowledge, demonstrated by higher A-NSKQ scores, than those classified as low risk (16.5 vs 14.5, p = 0.01). There was a very weak correlation between MAT and A-NSKQ scores (R2 = 0.012).

14.
Sci Rep ; 14(1): 9557, 2024 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-38664481

RESUMO

Breakthrough multi-response miniature dosimetry/spectrometry of electroneutrons (EN) was made on surface and in-depths of whole-body polyethylene phantom under 10 cm × 10 cm electron beam of 20 MV Varian Clinac 2100C electron medical accelerator commonly applied for prostate treatment. While dosimetry/spectrometry of photoneutrons (PN) has been well characterized for decades, those of ENs lagged behind due to very low EN reaction cross section and lack of sensitive neutron dosimeters/spectrometers meeting neutron dosimetry requirements. Recently, Sohrabi "miniature neutron dosimeter/spectrometer" and "Stripe polycarbonate dosimeter" have broken this barrier and determined seven EN ambient dose equivalent (ENDE) (µSv.Gy-1) responses from electron beam and from albedo ENs including beam thermal (21 ± 2.63), albedo thermal (43 ± 3.70), total thermal (64 ± 6.33), total epithermal (32 ± 3.90), total fast (112.00), total thermal + epithermal (l96 ± 10), and total thermal + epithermal + fast (208 ± 10.23) ENs. Having seven ENDE responses of this study and seven PNDE responses of previous study with the same accelerator obtained at identical conditions by the same principle author provided the opportunity to compare the two sets of responses. The PNDE (µSv.Gy-1) responses have comparatively higher values and 22.60 times at isocenter which provide for the first time breakthrough ENDE responses not yet reported in any studies before worldwide.


Assuntos
Aceleradores de Partículas , Radiometria , Aceleradores de Partículas/instrumentação , Radiometria/instrumentação , Radiometria/métodos , Nêutrons , Humanos , Elétrons , Imagens de Fantasmas
15.
J Diabetes ; 16(5): e13556, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38664878

RESUMO

AIMS: The adverse effects of sedentary behavior on obesity and chronic diseases are well established. However, the prevalence of sedentary behavior has increased, with only a minority of individuals meeting the recommended physical activity guidelines. This study aimed to investigate whether habitual leg shaking, a behavior traditionally considered unfavorable, could serve as an effective strategy to improve energy metabolism. MATERIALS AND METHODS: A randomized crossover study was conducted, involving 15 participants (mean [SD] age, 25.4 [3.6]; mean [SD] body mass index, 22 [3]; 7 women [46.7%]). The study design involved a randomized sequence of sitting and leg shaking conditions, with each condition lasting for 20 min. Energy expenditure, respiratory rate, oxygen saturation, and other relevant variables were measured during each condition. RESULTS: Compared to sitting, leg shaking significantly increased total energy expenditure [1.088 kj/min, 95% confidence interval, 0.69-1.487 kj/min], primarily through elevated carbohydrate oxidation. The average metabolic equivalent during leg shaking exhibited a significant increase from 1.5 to 1.8. Leg shaking also raised respiratory rate, minute ventilation, and blood oxygen saturation levels, while having no obvious impact on heart rate or blood pressure. Electromyography data confirmed predominant activation of lower leg muscles and without increased muscle fatigue. Intriguingly, a significant correlation was observed between the increased energy expenditure and both the frequency of leg shaking and the muscle mass of the legs. CONCLUSIONS: Our study provides evidence that habitual leg shaking can boost overall energy expenditure by approximately 16.3%. This simple and feasible approach offers a convenient way to enhance physical activity levels.


Assuntos
Estudos Cross-Over , Metabolismo Energético , Perna (Membro) , Humanos , Feminino , Adulto , Masculino , Adulto Jovem , Comportamento Sedentário , Taxa Respiratória , Frequência Cardíaca/fisiologia
16.
Data Brief ; 54: 110398, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38665157

RESUMO

The data set describes variables collected from a French (N 48.84°, E 1.95°) field trial, over a twelve-year period (2009-2020), in which four innovative cropping systems designed to reach multiple environmental and production goals were assessed. The four cropping systems were designed with new combinations of agricultural practices; they differed in terms of pesticide uses, nitrogen inputs, tillage practices, and crop sequences. Both biotic and abiotic variables were measured. In a previous data paper, we focused on nitrogen fluxes collected from two systems, over eight years (2009-2016). In the present one, we enlarge the scope of the variables, including more crop descriptions and environmental indicators, from all four systems, and over a longer period (2009-2020). The biotic data are: growth stages; aboveground plant nitrogen content and biomass collected at different growth stages, depending on the species; yield components of all the crops; and yield harvested with a combine machine. No weed, crop disease, and pest data are described. The abiotic data are physical and chemical properties of the soil (i.e. texture, calcium carbonate content, pH, organic carbon contents, and nitrogen contents) collected at different assessment periods. All agricultural practices, and climate were regularly recorded, and the treatment frequency indexes and the energy consumptions were computed. These data could be used for benchmarking, to design low-input systems, to improve models for parameterization and validation, and to increase the predictive accuracy of models of crop growth and development, specifically for orphan species such as linseed, faba bean or hemp, and for soil carbon and soil nitrogen fluxes in various conditions.

17.
Heliyon ; 10(7): e29264, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38623222

RESUMO

The dish stirling technology holds great promise as a renewable energy solution for remote and off-grid electric regions, particularly in the southern areas of North Africa. In this research, we conducted simulations of a 100 kw Dish Stirling system to evaluate its feasibility in comparison to photovoltaic technology at five distinct locations in southern Algeria: Adrar (Bordj Badji Mokhtar), Illizi (Djanet), Tamanrasset (Ain Mertoutek), Tindouf, and Bechar. Our findings underscore the substantial potential of Dish Stirling Solar Power technology, with the Sahara region standing out as particularly promising. In this region, the Dish Stirling system consistently outperforms a 100 kw photovoltaic system across all selected locations. The Dish Stirling system achieves an average annual electricity generation of 256 mwh while simultaneously mitigating CO2 emissions by 177 tons annually. Among these locations, Djanet Illizi emerges as the most favorable, with the Dish Stirling system producing an impressive 288.43 mwh annually. This capacity is sufficient to meet the annual energy needs of 230 households, all while maintaining a competitive LCOE of 0.0378 USD/kwh. Comparative analysis with previous research illuminates the remarkable cost-effectiveness of Dish Stirling technology in southern Algeria, primarily due to its abundant direct normal irradiance levels. These findings underscore the immense potential of Dish Stirling systems as a clean and highly efficient energy solution, well-suited for demanding to address the energy needs of remote environments, such as those found in the southern border regions of Algeria.

18.
Heliyon ; 10(7): e26320, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38623246

RESUMO

Agglomeration of wet particles, i.e., particles coated with a thin liquid layer, is a common phenomenon in many processes like fluidized bed combustion of low rank fuels. The availability of an agglomeration model that can evaluate the outcome of a binary collision between wet particles differing in solid particle properties, liquid layer thicknesses, and initial collision (impact) speeds is essential for obtaining a comprehensive understanding on the existing processes experiencing wet particle agglomeration or for a successful development of new processes with high chances of wet particle agglomeration. This study presents a generalized agglomeration model on the basis of energy conservation before and after collision when colliding wet particles may differ in solid particle properties, liquid layer thicknesses, and impact speeds. The model was established based on the approximate values of energy losses that may happen during the collision. It incorporates body forces, solid-solid contacting, liquid capillary, and viscous contributions, as well as the liquid bridge volume effect. Predictions of the new model for collision outcomes of identical wet particles were like those from an analytical energy balance model developed recently by the group for identical wet particles. We also validated the new model by experimental data from literature. The results of a collision direction analysis indicated that the direction often has a minimal effect on the collision outcome in many practical scenarios. The results of Monte Carlo uncertainty analyses with the new model revealed that proper estimations of impact speed, under capillary limiting conditions, and thickness of coating layers and asperity heights, under viscous limiting conditions, are critical for the realistic prediction of collision outcomes at impact speeds close to critical impact speed, i.e., the minimum particle speed required for the particles to rebound.

19.
iScience ; 27(4): 109549, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38623328

RESUMO

Independently run single microgrids (MGs) encounter difficulties with inadequate self-consumption of local renewable energy and frequent power exchange with the grid. Combining numerous MGs to form a multi-microgrid (MMG) is a viable approach to enhance smart distribution networks' operational and financial performance. However, the correlation and coordination of intermittent power generation within each MG network pose many techno-economic challenges for energy sharing and trading. This review offers a comprehensive analysis of these challenges within the framework of MMG operations. It examines state-of-the-art methodologies for optimizing multi-energy dispatch and scrutinizes contemporary strategies within energy markets that contribute to the resilience of power systems. The discourse extends to the burgeoning role of blockchain technology in revolutionizing decentralized market frameworks and the intricacies of MMG coordination for reliable and cost-effective energy distribution. Overall, this study provides ample inspiration for theoretical and practical research to the new entrants and experts alike to develop new concepts for energy markets, scheduling and novel operating models for future resilient multi-energy networked systems/MMGs.

20.
iScience ; 27(4): 109554, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38623334

RESUMO

A well-designed and managed electricity supply infrastructure system is essential for integrated energy market. This paper tracks progress on infrastructure for electricity trading in East Africa integrated electricity market. Using data on electricity infrastructure targets in Master Plan 2013-2023 and actual infrastructure delivered by 2022, we conducted earned value analysis (EVA) to establish whether the completed generation and transmission infrastructure can adequately facilitate electricity trading across EAC countries. Findings show that by 2022 the region had realized 54% of the 12,567MW planned generation capacity and 211% of transmission network targets. Investment inflows for infrastructure have been faster than anticipated with actual variance of 325%. This triggered 47% earned value in surplus load worth US$357million of trade, despite actual electricity trading not happening at the same pace. We construed some merit-order conditions for iterative planning to synchronize generation infrastructure with transmission infrastructure for trade efficiency.

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