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1.
Nature ; 603(7902): 631-636, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35322249

RESUMEN

Metastable phases-kinetically favoured structures-are ubiquitous in nature1,2. Rather than forming thermodynamically stable ground-state structures, crystals grown from high-energy precursors often initially adopt metastable structures depending on the initial conditions, such as temperature, pressure or crystal size1,3,4. As the crystals grow further, they typically undergo a series of transformations from metastable phases to lower-energy and ultimately energetically stable phases1,3,4. Metastable phases sometimes exhibit superior physicochemical properties and, hence, the discovery and synthesis of new metastable phases are promising avenues for innovations in materials science1,5. However, the search for metastable materials has mainly been heuristic, performed on the basis of experiences, intuition or even speculative predictions, namely 'rules of thumb'. This limitation necessitates the advent of a new paradigm to discover new metastable phases based on rational design. Such a design rule is embodied in the discovery of a metastable hexagonal close-packed (hcp) palladium hydride (PdHx) synthesized in a liquid cell transmission electron microscope. The metastable hcp structure is stabilized through a unique interplay between the precursor concentrations in the solution: a sufficient supply of hydrogen (H) favours the hcp structure on the subnanometre scale, and an insufficient supply of Pd inhibits further growth and subsequent transition towards the thermodynamically stable face-centred cubic structure. These findings provide thermodynamic insights into metastability engineering strategies that can be deployed to discover new metastable phases.

2.
Molecules ; 24(14)2019 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-31311184

RESUMEN

Herein, contaminants remaining in distillate and distillers' stillage were quantitatively measured after distillation. After rice bran powder was contaminated with 10 ppm of lead (Pb) and cadmium (Cd) or 0.02-1.27 ppm of five pesticides (terbufos, fenthion, iprobenfos, flutolanil, and ethoprophos) followed by fermentation, single-stage distillation was performed. In the obtained distillate, no Pb or Cd was found, as expected. However, when the pesticides were added as contaminants, trace-0.05 ppm of some pesticides were detected in the distillate, possibly due to the high vapor pressure (e.g., that of ethoprophos) and contamination amount (e.g., that of flutolanil, terbufos, and fenthion). In contrast, none of the contaminating pesticides were observed in the distilled spirits when a fermented liquefaction contaminated with 0.04-4 ppm of six pesticides (fenthion, terbufos, ethoprophos, iprobenfos, oxadiazon, and flutolanil) was distilled using a pilot-plant scale distillation column, indicating that the pesticides hardly migrate to the distilled spirits.


Asunto(s)
Bebidas Alcohólicas/análisis , Contaminación de Alimentos/análisis , Oryza/química , Residuos de Plaguicidas/análisis , Anilidas/análisis , Cadmio/análisis , Destilación , Fentión/análisis , Fermentación , Plomo/análisis , Organotiofosfatos , Compuestos Organotiofosforados/análisis , Proyectos Piloto
3.
Ophthalmic Plast Reconstr Surg ; 34(4): e121-e123, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29923967

RESUMEN

Kimura disease has been known as a chronic inflammatory disease of unknown etiology, since the first report in 1937 and characterized by an increased eosinophil fraction in peripheral blood, increased serum immunoglobulin E (IgE) levels, and lymphoid granuloma with eosinophilic infiltration on histopathological examination. The authors present a 30-year-old man who visited their clinic with a 3-month history of protrusion and conjunctival injection of the right eye. Surgical mass resection was performed, and initial histopathology revealed Kimura disease. Additional immunohistochemical examination revealed IgG4-related disease in another hospital, which showed more than 80 IgG4-positive plasma cells per high-power field and an IgG4+/IgG+ ratio more than 40%. There are histopathological similarities, and several reports have suggested a relationship between Kimura disease and IgG4-related disease. Thus, it is difficult to classify them as completely different diseases. Kimura disease and IgG4 can be considered a part of a clinical spectrum of abnormal immune reactions.


Asunto(s)
Hiperplasia Angiolinfoide con Eosinofilia/diagnóstico , Inmunoglobulina G/sangre , Enfermedades Orbitales/diagnóstico , Adulto , Humanos , Masculino
4.
J Comput Assist Tomogr ; 41(2): 236-241, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-27680420

RESUMEN

OBJECTIVE: This study examined the effect of coronary artery calcification score by lifestyle and correlation with coronary artery stenosis in persons who underwent coronary artery computed tomography (CT) angiography among health examinees for heart diseases in Korea. METHODS AND MATERIALS: The study included 506 subjects (256 men and 250 women) who underwent coronary artery CT angiography among health examines for heart diseases at the Incheon Branch of the Korea Association of Health Promotion between January 2, 2014, and December 31, 2014. The demographical variables of the subjects were determined by frequency analysis, and the difference by sex was compared and analyzed using χ independence test. Independent 2-sample t test was performed to determine any difference in main factors by coronary artery calcification. RESULTS: According to the results, 175 (34.6%) had calcification, men showed statistically higher scores than women, and calcification seemed higher in those who were older, taller, heavier, and thicker in waist. Regarding blood pressure, calcification was shown if contraction phase and relaxation blood pressure was higher, blood sugar before meal was higher, and neutral fat was higher. By lifestyle, calcification seemed to be higher in those with more alcohol drinking per week, long past smoking years, and higher smoking amount per day in the past and present. In addition, coronary artery stenosis rate showed statistical correlation with calcification from the left anterior descending artery, right coronary artery, left circumflex artery, and left main coronary artery in sequence. CONCLUSIONS: In conclusion, coronary artery calcification score CT is deemed to be a suitable method for the estimation of coronary artery stenosis with short examination time, low radiation exposure, and noninvasive method.


Asunto(s)
Calcinosis/diagnóstico por imagen , Angiografía por Tomografía Computarizada/métodos , Angiografía Coronaria/métodos , Estenosis Coronaria/diagnóstico por imagen , Estilo de Vida , Tomografía Computarizada Multidetector/métodos , Factores de Edad , Composición Corporal , Vasos Coronarios/diagnóstico por imagen , Femenino , Humanos , Masculino , Persona de Mediana Edad , República de Corea , Factores de Riesgo , Factores Sexuales
5.
Environ Geochem Health ; 39(2): 345-352, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28213721

RESUMEN

Remediation of potentially toxic trace elements (PTEs) in paddy fields is fundamental for crop safety. In situ application of chemical amendments has been widely adapted because of its cost-effectiveness and environmental safety. The main purpose of this research was to (1) evaluate the reduction in dissolved concentrations of cadmium (Cd) and arsenic (As) with the application of chemical amendments and (2) monitor microbial activity in the soil to determine the remediation efficiency. Three different chemical amendments, lime stone, steel slag, and acid mine drainage sludge, were applied to paddy fields, and rice (Oryza sativa L. Milyang 23) was cultivated. The application of chemical amendments immobilized both Cd and As in soil. Between the two PTEs, As reduction was significant (p < 0.05) with the addition of chemical amendments, whereas no significant reduction was observed for Cd than that for the control. Among six soil-related variables, PTE concentration showed a negative correlation with soil pH (r = -0.70 for As and r = -0.54 for Cd) and soil respiration (SR) (r = -0.88 for As and r = -0.45 for Cd). This result indicated that immobilization of PTEs in soil is dependent on soil pH and reduces PTE toxicity. Overall, the application of chemical amendments could be utilized for decreasing PTE (As and Cd) bioavailability and increasing microbial activity in the soil.


Asunto(s)
Arsénico/farmacocinética , Cadmio/farmacocinética , Restauración y Remediación Ambiental/métodos , Microbiología del Suelo , Contaminantes del Suelo/farmacocinética , Arsénico/análisis , Disponibilidad Biológica , Biomasa , Cadmio/análisis , Carbonato de Calcio , Oryza , Mejoramiento de la Calidad , República de Corea , Aguas del Alcantarillado , Suelo/química , Contaminantes del Suelo/análisis
6.
Inorg Chem ; 55(17): 8359-70, 2016 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-27494550

RESUMEN

Eu(2+)-activated M5(PO4)3X (M = Ca, Sr, Ba; X = F, Cl, Br) compounds providing different alkaline-earth metal and halide ions were successfully synthesized and characterized. The emission peak maxima of the M5(PO4)3Cl:Eu(2+) (M = Ca, Sr, Ba) compounds were blue-shifted from Ca to Ba (454 nm for Ca, 444 nm for Sr, and 434 nm for Ba), and those of the Sr5(PO4)3X:Eu(2+) (X = F, Cl, Br) compounds were red-shifted along the series of halides, F → Cl → Br (437 nm for F, 444 nm for Cl, and 448 nm for Br). The site selectivity and occupancy of the activator ions (Eu(2+)) in the M5(PO4)3X:Eu(2+) (M = Ca, Sr, Ba; X = F, Cl, Br) crystal lattices were estimated based on theoretical calculation of the 5d → 4f transition energies of Eu(2+) using LCAO. In combination with the photoluminescence measurements and theoretical calculation, it was elucidated that the Eu(2+) ions preferably enter the fully oxygen-coordinated sites in the M5(PO4)3X:Eu(2+) (M = Ca, Sr, Ba; X = F, Cl, Br) compounds. This trend can be well explained by "Pauling's rules". These compounds may provide a platform for modeling a new phosphor and application in the solid-state lighting field.

7.
J Xray Sci Technol ; 23(3): 321-30, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26410466

RESUMEN

We found a way to optimize the image quality and reduce the exposure dose of patients through the proper activity combination of the automatic exposure control system chamber for the dose optimization when examining the pelvic anteroposterior side using the phantom of the human body standard model. We set 7 combinations of the chamber of automatic exposure control system. The effective dose was yielded by measuring five times for each according to the activity combination of the chamber for the dose measurement. Five radiologists with more than five years of experience evaluated the image through picture archiving and communication system using double blind test while classifying the 6 anatomical sites into 3-point level (improper, proper, perfect). When only one central chamber was activated, the effective dose was found to be the highest level, 0.287 mSv; and lowest when only the top left chamber was used, 0.165 mSv. After the subjective evaluation by five panel members on the pelvic image was completed, there was no statistically meaningful difference between the 7 chamber combinations, and all had good image quality. When testing the pelvic anteroposterior side with digital radiography, we were able to reduce the exposure dose of patients using the combination of the top right side of or the top two of the chamber.


Asunto(s)
Pelvis/diagnóstico por imagen , Dosis de Radiación , Intensificación de Imagen Radiográfica/métodos , Humanos , Fantasmas de Imagen
8.
BMC Complement Altern Med ; 14: 272, 2014 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-25074485

RESUMEN

BACKGROUND: Type 2 diabetes is a serious problem for developed countries. Prevention of prediabetes progression to type 2 diabetes with the use of natural products appears to a cost-effective solution. Previously we showed that enzymatically digested low molecular weight chitosan-oligosaccharide with molecular weight (MW) below 1,000 Da (GO2KA1) has potential for hyperglycemia management. METHODS: In this study we evaluated the effect of long-term supplementation of GO2KA1 on hyperglycemia using a db/db mice model. Additionally, we evaluated the effect of GO2KA1 on sucrase and glucoamylase activities and expression, using the same db/db mice model. RESULTS: After 42 days we observed that GO2KA1 supplementation reduced both the blood glucose level and HbA1c in a similar manner with a known anti-diabetic drug, acarbose. When the sucrase and glucoamylase activities of GO2KA1 and control mice were evaluated using enzymatic assay, we observed that GO2KA1 significantly inhibited sucrase in all 3 parts of the intestine, while glucoamylase activity was significantly reduced only in the middle and lower part. When the sucrase-isomaltase (SI) complex expression on mRNA level was evaluated, we observed that GO2KA1 had minimal inhibitory effect on the upper part, more pronounced inhibitory effect on the middle part, while the highest inhibition was observed on the lower part. Our findings suggest that long-term GO2KA1 supplementation in db/db mice results to significant blood glucose and HbA1c reduction, to levels similar with those of acarbose. Furthermore, our findings confirm previous in vitro observations that GO2KA1 has inhibitory effect on carbohydrate hydrolysis enzymes, namely sucrase, maltase and SI complex. CONCLUSIONS: Results from this study provide a strong rationale for the use of GO2KA1 for type 2 diabetes prevention, via inhibition of carbohydrate hydrolysis enzymes. Based on the findings of this animal trial, clinical trials will be designed and pursued.


Asunto(s)
Glucemia/efectos de los fármacos , Quitosano/análogos & derivados , Quitosano/farmacología , Diabetes Mellitus Experimental/tratamiento farmacológico , Hiperglucemia/tratamiento farmacológico , Oligosacáridos/farmacología , Estado Prediabético/tratamiento farmacológico , Animales , Peso Corporal/efectos de los fármacos , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/prevención & control , Ingestión de Alimentos/efectos de los fármacos , Hemoglobina Glucada/metabolismo , Glicósido Hidrolasas/metabolismo , Hiperglucemia/sangre , Hiperglucemia/metabolismo , Intestinos/enzimología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Estado Prediabético/sangre , Estado Prediabético/metabolismo
9.
Artículo en Inglés | MEDLINE | ID: mdl-38267645

RESUMEN

This study analyzes the performance and cost-effectiveness of a protrusion-roughened jet-impinged double-pass solar air collector (PRJDPSAC) within a Reynolds number (Re) range of 2500 to 22,500. Examining jet slot parameters, i.e., the jet height ratio (Hjp/Dhd = 0.11-0.44), stream-wise pitch ratio (Xjp/Dhd = 0.44-1.32), and span-wise pitch ratio (Yjp/Dhd = 0.44-1.32), the model demonstrates enhanced energy conversion, minimizes losses, improves efficiency, and brings positive economic impact, making it a promising solution for diverse applications including drying processes, livestock facilities, remote accommodations, and HVAC system pre-heating. The examination incorporates advanced MATLAB simulations to assess energy-exergy performance and cost viability. At lower Re values, both energy ([Formula: see text]) and exergy ([Formula: see text]) efficiencies increase uniformly; however, stabilization and decline occur at higher Re values. The maximum [Formula: see text] for the PRJDPSAC is 4.38% under a temperature rise parameter of 60 × 10-3 Km2/W for obtaining optimum values of Xjp/Dhd = 1.32, Hjp/Dhd = 0.22, and Yjp/Dhd = 1.32, which is 31% higher than that of the smooth double-pass solar air collector (DPSAC). Economic benefits are significant for PRJDPSAC within mair (0.01-0.07 kg/s), but above 0.07 kg/s, the DPSAC becomes more cost-effective. Integrating simulation and experimental data, the study highlights MATLAB's effectiveness for solar energy system analysis and optimization, reinforcing the practicality of the proposed collector design.

10.
Toxics ; 12(2)2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38393230

RESUMEN

Released antibiotics from source to stream can influence bacterial communities and potentially alter the ecosystem. This research provides a comprehensive examination of the sources, distribution, and bacterial community dynamics associated with varied antibiotic release sources adjacent to the stream. The residual of antibiotics from different sources was determined, and the bacterial community structure was examined to reveal the differences in the bacteria community in the stream. The residual of antibiotics was quantified with liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the Illumina MiSeq platform was utilized to sequence bacterial 16S rRNA genes, providing comprehensive insights into the bacterial community structure in the sediment across five different sites. Results indicated that the presence and distribution of antibiotics were significantly influenced by released sources. In the case of the bacterial community, the Proteobacteria and Firmicutes were the most dominant phyla in the sediment, and especially, the Firmicutes showed higher abundance in sites mostly affected by livestock sources. Additionally, livestock gut bacteria such as Clostridium saudiense, Proteiniclasticum ruminis, and Turicibacter sanguinis were prevalent in antibiotic-contaminated sites adjacent to livestock facilities. Overall, this study provides critical insights into the effect of antibiotic contamination by verifying the relationship between the occurrence of antibiotic residuals and the alteration in the bacterial community in the stream.

11.
Artículo en Inglés | MEDLINE | ID: mdl-38607487

RESUMEN

In building cooling, the demand for cooling surges during specific times, stressing air-conditioner operation, and additional cooling is often wasted during low-demand periods. Water-phase change material (W-PCM)-based thermal energy storage (TES) allows for load shifting and effective management of peak demand by storing cooling energy when the demand is low. This stored energy can be deployed during peak hours, decreasing energy usage and associated CO2 emissions. However, the use of W-PCMs was hindered by phase separation, slow energy transfer, and high supercooling degree (SCD). We synthesized coconut shell (CNS)-produced activated carbon (ACC) to use as a thermal enhancer in W-PCMs for the first time. First, ACC was synthesized from CNS via steam activation. Then, transmission electron microscopy was used to confirm the pore morphology of the CNS-ACC. The synthesis of the W-PCM with various weight percentages (0.1, 0.6, and 1.2) of CNS-ACC was accomplished in two steps. Zeta potential distribution analysis revealed that the W-PCM with CNS-ACC exhibited colloidal stability. Thermal conductivity (TC) and thermogram analyses revealed that a dose of 1.2 wt% CNS-ACC enhanced liquid and solid TC by 9% and 22%, respectively, despite a 6% and 8% decrease in specific heat and latent heat. More specifically, solidification assessment in a spherical enclosure revealed 100% suppression of SCD with 1.2 wt% CNS-ACC. As a result of this and the enhanced TC, the overall solidification process was accelerated, reducing the overall duration by 18.5%. Thus, the combination of CNS-derived ACC and W-PCM for TES in building cooling could reduce energy consumption and associated CO2 emissions.

12.
Environ Sci Pollut Res Int ; 31(15): 22802-22813, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38411914

RESUMEN

The alginate-biochar formulation for metal removal from aquatic environments has been widely tried but its use for lowering phytoavailability of metals in the soil-crop continuum is limited. Biochar has been increasingly used as a soil amendment due to its potential for soil carbon sequestration and sorption capacity. Handling of powdery biochar as a soil top-dressing material is, however, cumbersome and vulnerable to loss by water and wind. In this experiment, biochar powder, which was pyrolyzed from oak trees, was encapsulated into beads with alginate, which is a naturally occurring polysaccharide found in brown algae. Both batch and pot experiments were conducted to examine the effects of the alginate-encapsulated biochar beads (BB), as compared to its original biochar powdery form (BP), on the Pb adsorption capacity and phytoavailability of soil Pb to lettuce (Lactuca sativa L.). The BB treatment improved reactivity about six times due to a higher surface area (287 m2 g-1) and five times due to a higher cation exchange capacity (50 cmolc kg-1) as compared to the BP treatment. The maximum sorption capacity of Pb was increased to 152 from 81 mg g-1 because of surface chemosorption. Adsorption of Pb onto BB followed multiple first-order kinetics and comprised fast and slow steps. More than 60% of the Pb was adsorbed in the fast step, i.e., within 3 h. Also, the BB treatment, up to the 5% level (w/w), increased soil pH from 5.4 to 6.5 and lowered the phytoavailable fraction of Pb in soil from 5.7 to 0.3 mg kg-1. The Pb concentrations in lettuce cultivated at 5% for the BP and BB treatments were similar but 63 and 66% lower, respectively, than those of the control soil. The results showed that the encapsulation of biochar with alginate enhanced adsorption by the biochar.


Asunto(s)
Lactuca , Contaminantes del Suelo , Plomo , Suelo , Alginatos , Contaminantes del Suelo/análisis , Carbón Orgánico
13.
ACS Appl Mater Interfaces ; 16(14): 17683-17691, 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38531014

RESUMEN

Porous thermoelectric materials offer exciting prospects for improving the thermoelectric performance by significantly reducing the thermal conductivity. Nevertheless, porous structures are affected by issues, including restricted enhancements in performance attributed to decreased electronic conductivity and degraded mechanical strength. This study introduces an innovative strategy for overcoming these challenges using porous Bi0.4Sb1.6Te3 (BST) by combining porous structuring and interface engineering via atomic layer deposition (ALD). Porous BST powder was produced by selectively dissolving KCl in a milled mixture of BST and KCl; the interfaces were engineered by coating ZnO films through ALD. This novel architecture remarkably reduced the thermal conductivity owing to the presence of several nanopores and ZnO/BST heterointerfaces, promoting efficient phonon scattering. Additionally, the ZnO coating mitigated the high resistivity associated with the porous structure, resulting in an improved power factor. Consequently, the ZnO-coated porous BST demonstrated a remarkable enhancement in thermoelectric efficiency, with a maximum zT of approximately 1.53 in the temperature range of 333-353 K, and a zT of 1.44 at 298 K. Furthermore, this approach plays a significant role in enhancing the mechanical strength, effectively mitigating a critical limitation of porous structures. These findings open new avenues for the development of advanced porous thermoelectric materials and highlight their potential for precise interface engineering through the ALD.

14.
Ophthalmic Plast Reconstr Surg ; 29(6): 500-2, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24217482

RESUMEN

PURPOSE: To introduce the sutureless technique to appose flaps using the BioGlue composed of bovine serum albumin (45%) and glutaraldehyde (10%) in the external dacryocystorhinostomy (DCR). METHODS: The clinical chart was reviewed, retrospectively. The authors studied 31 case series of 30 patients who underwent the external DCR using the BioGlue in the step of apposing flaps. Instead of the suture technique, BioGlue was applied to appose flaps. Other steps were performed in the similar fashion to the conventional external DCR. And also, authors studied 31 case series of 30 patients who underwent the external DCR with conventional suture technique. RESULTS: Mean follow-up period is 12.5 months in study group and 12.6 months in control group. During mean follow up, 3 cases of membrane formation were observed, and patency of the anastomosis was kept well established in 28 cases (90%) in both groups. CONCLUSIONS: Sutureless apposition of flaps using the BioGlue can be an alternative method for the conventional suture technique in the external DCR. Also, it is easy and safe procedure to perform.


Asunto(s)
Dacriocistorrinostomía/métodos , Proteínas/administración & dosificación , Colgajos Quirúrgicos , Adhesivos Tisulares/administración & dosificación , Adulto , Anciano , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Técnicas de Sutura
15.
Heliyon ; 9(2): e12964, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36816275

RESUMEN

In Korea, the use of fire-detection systems applying IoT technology to existing analog fire-alarm systems has increased owing to the communication technology convergence, the world's best Internet network, and the proliferation of Internet of Things (IoT). Its use can be expected to increase worldwide in the future. For IoT-based fire-detection systems to exhibit the requisite reliability (based on a low false-alarm rate), research related to the analysis of detection signals should be actively promoted and conducted. However, there has been no research activity based on actual operational data, apart from the research that has been conducted in laboratory environments. The primary reason for this state of affairs has been that the installation and use of IoT-based fire-detection systems on a large scale has been rare, worldwide. Consequently, with respect to the fire-signal characteristics of IoT-based fire-detection systems, related data in this study were obtained by investigating actual fire accident cases, using fire alarm data that occurred over a period of 5 years. Based on the signal pattern analysis results using these field data, a fuzzy logic system for recognizing fire signal patterns was developed and verified. As a result, in the actual fire accidents examined, an "alarm" condition-corresponding to the high possibility of fire among the five fire alarms-was determined 30 s before the actual fire alarm. Moreover, it was also found that approximately 80% of non-fire alarms could be reduced in the actual fire alarms that occurred at Institute K during the 5-year period examined.

16.
Environ Sci Pollut Res Int ; 30(13): 36259-36275, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36547837

RESUMEN

The effect of the flow and geometric parameters of a dimple-roughened absorber plate on the enactment of solar air collectors (SACs) with air-impinged jets was investigated in this study. The performance-defining criteria (PDCs) of a jet-impinged dimple-roughened SAC (JIDRSAC)-forced convection airflow system are significantly affected by variations in the system's control factors (CFs), such as the arc angle (αaa) ranging from 30° to 75°, dimple pitch ratio (pd/Dh) ranging from 0.269 to 1.08, and dimple height ratio (ed/Dh) ranging from 0.016 to 0.0324. The constant parameters of the jet slot are a stream-wise pitch ratio (Xi/Dhd) is 1.079, a span-wise pitch ratio (Yi/Dhd) is 1.619, and a jet diameter(Di/Dhd) is 0.081. Based on the combined approach of the analytic hierarchy process and multi-attributive border approximation area comparison (AHP-MABAC), the Reynolds number (Re) = 15,000, αaa = 60°, pd/Dh = 0.27, and ed/Dh = 0.027 depicted the best alternative (A-9) set among 16 alternatives to deliver the optimal performance of the JIDRSAC. The jet impingement pass compared to the smooth pass, the Nusselt number increased by 2.16-2.81, and friction factor increased by 3.35-5.95, and JIDRSAC was compared to the jet impingement pass, exhibiting an enhancement in Nusselt number and friction factor in the range of 0.55-0.80 and 0.05-0.15, respectively. In addition, sensitivity analysis is used to examine the ranking's stability and reliability in relation to the PDC weights.


Asunto(s)
Luz Solar , Reproducibilidad de los Resultados
17.
Environ Sci Pollut Res Int ; 30(31): 77807-77818, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37266779

RESUMEN

This work aims to enhance the performance of a solar air heater (SAH) by introducing broken V-ribs as roughness elements on the absorber plate. The unit with a conventional flat absorber plate is referred to as the "FSAH," while the unit with a broken V-rib-shaped absorber plate is called the "VSAH." The experiment was performed for three air velocities: 25 m/s, 20 m/s, and 15 m/s and the corresponding air flow rates were 0.037 kg/s, 0.031 kg/s, and 0.023 kg/s, respectively. The results showed that the maximum temperature was experienced on the absorber plate, followed by the glass plate for both SAHs. Overall, the average absorber and glass plate temperatures of the VSAH were 0.6-1.4 °C and 0.4-1.9 °C lower than those of the FSAH. Compared to the FSAH, the experimental results showed that the VSAH experienced useful power and thermal efficiency that were 16.6-19.8% and 15.7-20.4% higher, respectively, while the top surface heat losses were found to decrease by 2.1-8.1%. Due to the disrupted air paths in the VSAH, the observed pressure drop was 113.3-133.3% higher than that of the FSAH. More impotently, the thermo-hydraulic performance factor was always higher 1 and the observed values were 1.48, 1.39, and 1.24 at the va (velocity) values of 15, 20, and 25 m/s, respectively. Therefore, the proposed VSAH had an admirable thermal performance as compared to FSAH. Further, optimization through varying the roughness parameters, namely, relative blockage width (W/w), relative pitch ratio (P/e), number of baffles (n), relative blockage height (e/H), and angle of attack (ß) could helped to achieve better performance.


Asunto(s)
Energía Solar , Luz Solar , Temperatura , Costillas
18.
J Phys Chem Lett ; 14(28): 6486-6493, 2023 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-37439679

RESUMEN

Understanding the initial growth process during atomic layer deposition (ALD) is essential for various applications employing ultrathin films. This study investigated the initial growth of ALD Ir films using tricarbonyl-(1,2,3-η)-1,2,3-tri(tert-butyl)-cyclopropenyl-iridium and O2. Isolated Ir nanoparticles were formed on the oxide surfaces during the initial growth stage, and their density and size were significantly influenced by the growth temperature and substrate surface, which strongly affected the precursor adsorption and surface diffusion of the adatoms. Higher-density and smaller nanoparticles were formed at high temperatures and on the Al2O3 surface, forming a continuous Ir film with a smaller thickness, resulting in a very smooth surface. These findings suggest that the initial growth behavior of the Ir films affects their surface roughness and continuity and that a comprehensive understanding of this behavior is necessary for the formation of continuous ultrathin metal films.

19.
Environ Int ; 175: 107963, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-37192573

RESUMEN

Arsenic (As)-contaminated soil inevitably exists in nature and has become a global challenge for a sustainable future. Current processes for As capture using natural and structurally engineered nanomaterials are neither scientifically nor economically viable. Here, we established a feasible strategy to enhance As-capture efficiency and ecosystem health by structurally reorganizing iron oxyhydroxide, a natural As stabilizer. We propose crystallization to reorganize FeOOH-acetate nanoplatelets (r-FAN), which is universal for either scalable chemical synthesis or reproduction from natural iron oxyhydroxide phases. The r-FAN with wide interlayer spacing immobilizes As species through a synergistic mechanism of electrostatic intercalation and surface chemisorption. The r-FAN rehabilitates the ecological fitness of As-contaminated artificial and mine soils, as manifested by the integrated bioassay results of collembolan and plants. Our findings will serve as a cornerstone for crystallization-based material engineering for sustainable environmental applications and for understanding the interactions between soil, nanoparticles, and contaminants.


Asunto(s)
Arsénico , Contaminantes del Suelo , Arsénico/análisis , Ecosistema , Cristalización , Contaminantes del Suelo/análisis , Suelo/química
20.
Opt Express ; 20(23): A941-53, 2012 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-23326842

RESUMEN

We propose a method for calculating the optical response to partially-coherent light based on the coherence length. Using a Fourier transform of a randomly-generated partially-coherent wave, we demonstrate that the reflectance, transmittance, and absorption with the incidence of partially-coherent light can be calculated from the Poynting vector of the incident coherent light. We also demonstrate that the statistical field distribution of partially-coherent light can be obtained from the proposed method using a rigorous coupled wave analysis. The optical characteristics of grating structures in photovoltaic devices are analyzed as a function of coherence length. The method is capable of providing a general procedure for analyzing the incoherent optical characteristics of thick layers or nano particles in photovoltaic devices with the incidence of partially-coherent light.

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