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Статті в журналах з теми "Negative difference effect (NDE)"
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Zhang, Wentai, Qijun Liu, Yingqi Chen, and Guojiang Wan. "Anodic dissolution dictates the negative difference effect (NDE) of magnesium corrosion more in chemical pathway." Materials Letters 232 (December 2018): 54–57. http://dx.doi.org/10.1016/j.matlet.2018.08.069.
Повний текст джерела
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Xu, Shanna, Junhua Dong, and Wei Ke. "Effect of Magnesium Hydride on the Corrosion Behavior of Pure Magnesium in 0.1 M NaCl Solution." International Journal of Corrosion 2010 (2010): 1–5. http://dx.doi.org/10.1155/2010/934867.
Повний текст джерелаАнотація:
The effect of magnesium hydride on the corrosion behavior of pure magnesium in 0.1 M NaCl solution was investigated using the gas collection method, potentiostatic current decay test, and in situ Raman spectrum. The formation of magnesium hydride (MgH2,Mg2H4) was observed at the cathodic region. Applying anodic potential leads to decomposition of magnesium hydride. Magnesium hydride plays an important role on the negative difference effect (NDE) in both the cathodic and anodic regions.
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Yu, Wei Dong, Xiao Min Li, Yi Wen Zhang, Rui Yang, Qun Wang, and Li Dong Chen. "Investigation of Bipolar Resistance Switching Properties in SrTiO3 Thin Films with Symmetric Electrodes Structure." Advanced Materials Research 66 (April 2009): 119–22. http://dx.doi.org/10.4028/www.scientific.net/amr.66.119.
Повний текст джерелаАнотація:
A noncrystalline SrTiO3 (STO) thin film was grown on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. The Pt thin film was deposited on STO film as top electrode, forming a symmetric structure (Pt/STO/Pt) to exclude the influence of the electrical difference in STO-electrode interfaces. It was found that a stable bipolar resistive switching was obtained in this structure. In a current sweep, an obvious S type negative differential conductance (NDC) phenomenon was found in both polarities. And in a voltage sweep, no NDC was observed due to the current control mechanism of S type NDC effect. The possible mechanism of this effect is discussed preliminarily.
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Peng, Chih-Sheng, and Peng-Wei Chu. "(Digital Presentation) Effect of Electrolyte Additives on the Discharge Behavior and Performance of a WE43 Mg Alloy As Mg-Air Battery Anode." ECS Meeting Abstracts MA2022-01, no. 1 (July 7, 2022): 126. http://dx.doi.org/10.1149/ma2022-011126mtgabs.
Повний текст джерелаАнотація:
Smartphones and electric cars have developed rapidly over the past ten years. Hence, high energy density storage devices are also getting increasing attention. Compared with commercial Li-ion batteries, Mg-air battery systems have the advantages of a high theoretical energy density (6800Wh/kg), natural abundance, environmental-friendliness, and low cost. However, Mg-air battery suffers from low anodic efficiency, discharge product accumulation, and sluggish reaction kinetics on both the anodes and cathodes. Adding additives to the electrolyte has been shown to increase the cell voltage and boost the anode efficiency. Nevertheless, the underlying mechanism of how electrolyte additives change the discharge behavior is still unclear. In this report, the discharge behavior and performance of a Mg-air battery with different electrolyte additives are investigated through a combination of electrochemical analysis, collection of the by-product hydrogen gas, and microscopic characterizations. A WE43 Mg alloy was selected as the anode for primary Mg-air batteries due to its high activity in 3.5wt% NaCl solution. Various amounts of electrolyte additives, such as chelating agents, e.g. salicylate salts, and corrosion inhibitors, e.g. Na3PO4, were added to 3.5wt% NaCl solution together or separately. The discharge behavior and performance with different additives were analyzed by recording the open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) before and after discharge, discharge voltage evolution, hydrogen evolved from the anodes, and cross-sectional observations of the alloy after discharge. The anodic efficiency loss contributed by the negative difference effect (NDE) and chunk effect (CE) were also quantified to study how different additives change the discharge behavior. The anode performance improvement and synergic effect of the electrolyte additives will be discussed. Figure 1
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Vaghefinazari, Bahram, Darya Snihirova, Cheng Wang, Linqian Wang, Min Deng, Daniel Höche, Sviatlana Lamaka, and Mikhail Zheludkevich. "Boosting Mg-Air Primary Battery Performance Via Addition of Complexing Agents in the Electrolyte: A Mechanistic View on the Effect of EDTA." ECS Meeting Abstracts MA2022-02, no. 1 (October 9, 2022): 3. http://dx.doi.org/10.1149/ma2022-0213mtgabs.
Повний текст джерелаАнотація:
Diverse novel energy conversion and storage systems have developed rapidly in the last few decades to address the growing demand for sustainable and environmentally friendly energy sources. In this respect, aqueous Mg-air batteries have drawn much attention for their high energy density, cost-effectiveness, and environmental friendliness. A primary Mg-air battery can theoretically provide a relatively high voltage and specific energy density of 3.1 V and 6.8 kW.h.kg-1, respectively [1]. However, the high wasteful self-corrosion rate of Mg alloys during discharge in aqueous electrolytes and fouling of the anode surface with corrosion products significantly reduce the delivered voltage and the specific energy of the Mg-air battery. These drawbacks are exacerbated by the anodic polarization due to the well-known phenomenon called Negative Difference Effect (NDE). Recently, pioneered by Höche et al. [2], the use of Mg complexing agents in the battery electrolyte has revolutionized the performance of Mg-air batteries by mitigating the mentioned shortcomings. However, the understanding of the enhancement mechanism, which may differ for different complexing agents, is at its nascent stage. In this work, sodium salt of ethylendiaminetetraacetic acid (EDTA) is used as the additive for the electrolyte of a primary Mg-air battery with a commercially pure Mg anode [3]. The electrolyte pH was taken as the main parameter to explore the effect of EDTA on the discharge performance of the Mg anode. The battery voltage was improved at all tested electrolyte pH values, which ranged from 7.0 to 11.0. The utilization efficiency (UE) of the discharged Mg anode is also enhanced by the presence of EDTA in the electrolyte at pH of 11, resulting in a 10-fold increase in the full-cell battery discharge time as compared to the reference battery in NaCl electrolyte without EDTA. Different methods, including EIS, local pH and dissolved O2 measurements, and H2 evolution tests were employed to study the interaction of EDTA with the Mg anode surface during discharge. Several mechanisms of enhancement in the UE have been concluded, including suppressing the chunk effect, weakening the detrimental NDE, and promoting the formation of a more protective layer on the Mg anode surface. The findings of this study provides an improved understanding of the interaction of the complexing agents with the Mg anode in Mg-air batteries, which further helps finding the tuning parameters to optimize its performance. [1] T. Zhang, Z. Tao, J. Chen, Magnesium-air batteries: From principle to application, Materials Horizons, 1 (2014) 196-206. [2] D. Höche, S.V. Lamaka, B. Vaghefinazari, T. Braun, R.P. Petrauskas, M. Fichtner, M.L. Zheludkevich, Performance boost for primary magnesium cells using iron complexing agents as electrolyte additives, Sci Rep, 8 (2018) 7578. [3] B. Vaghefinazari, D. Snihirova, C. Wang, L. Wang, M. Deng, D. Höche, S.V. Lamaka, M.L. Zheludkevich, Exploring the effect of sodium salt of Ethylenediaminetetraacetic acid as an electrolyte additive on electrochemical behavior of a commercially pure Mg in primary Mg-air batteries, Journal of Power Sources, 527 (2022) 231176.
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Cho, Young-Eun, Young-Jun Lim, Jung-Suk Han, In-Sung Luke Yeo, and Hyung-In Yoon. "Effect of Yttria Content on the Translucency and Masking Ability of Yttria-Stabilized Tetragonal Zirconia Polycrystal." Materials 13, no. 21 (October 22, 2020): 4726. http://dx.doi.org/10.3390/ma13214726.
Повний текст джерелаАнотація:
Translucent zirconia, manufactured by increasing the yttria content, offers improved translucency, but may have a negative effect on esthetic outcomes under clinical conditions such as discolored abutment because of the reflection of the underlying color. The purpose of this in vitro study was to compare the translucency parameter and masking ability of 3 mol % yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP (Katana HT)), 4Y-ZP (Katana STML), and 5Y-ZP (Katana UTML) with those of lithium disilicate (Rosetta SM). Zirconia and lithium disilicate specimens of 10 mm diameters and 0.8 and 1.5 mm thicknesses were fabricated. Their CIE L*a*b* values (L*, brightness; a*, red-green value; b*, yellow-blue value) were measured at the center of the specimens against black and white backgrounds using a spectrophotometer, and translucency parameter (TP) values were determined. The microstructure of the specimens was observed using scanning electron microscopy. Four cylindrical backgrounds of different shades were prepared. The zirconia and lithium disilicate specimens were placed on the backgrounds without any intervening medium. CIE L*a*b* values were obtained, and the color difference value (ΔE) was calculated. Thresholds for acceptability and perceptibility were assumed as ΔE = 5.5 and ΔE = 2.6, respectively, to evaluate masking ability. Data were compared using one-way analysis of variance and post-hoc was performed using Scheffe’s test (α = 0.05). In zirconia specimens, the TP value increased as the yttria content increased from 3 mol %, through 4 mol % to 5 mol %, and all zirconia specimens showed lower TP values than lithium disilicate specimens did. All zirconia specimens showed optimal masking ability against a normal dentin shade (ND3) and acceptable masking ability against titanium at a minimum thickness of 1.5 mm. However, no zirconia specimen could mask severely discolored dentin (ND9), regardless of thickness. The decrease in zirconia thickness from 1.5 to 0.8 mm significantly increased translucency. Monolithic Y-TZP ceramics could mask a normal dentin background but could not mask severely discolored dentin at either 0.8 or 1.5 mm thicknesses.
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de Castro Neto, Arthur Cesário, Fernanda Oliveira Magalhaes, Isabella Cecilio Resende Ferreira, Gyovanna de Oliveira Silva, Natalia Escoura Vendramini, Maria Vilaça Omena Silva, Amanda Vilela Leão, et al. "Feed Consumption and Weight Gain in Diabetic and Non-Diabetic Rats Treated With Azadirachta Indica (Neem) and Plathymenia Reticulata." Journal of the Endocrine Society 5, Supplement_1 (May 1, 2021): A46—A47. http://dx.doi.org/10.1210/jendso/bvab048.092.
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Abstract Introduction: Neem (Azadirachta indica A. Juss, Meliaceae) is a tree native to India that has several medicinal effects. It has been reported that the leaves and oil of Neem seeds present antihyperglycemic/hypoglycemic activity. Plathymenia reticulata benth, known as “vinhático”, is a Brazilian cerrado tree that has properties of pancreatic islet hyperplasia and glycemic control in diabetic rats. Objective: To verify weight gain correlating with feed intake in rats with type 1 and non-diabetic diabetes mellitus, undertreatment with Neem and Plathymenia and the association between them. Methodology: Diabetes was induced by intraperitoneal streptozotocin (65mg/kg) administration after a 24-hour fast. The diagnosis was made using a blood glucose value above 200mg/dl. The study was conducted in 60 male adult Wistar rats, weighing between 180 and 220 grams, divided into 9 groups, between diabetics (DM) and non-diabetic controls (NDC), and treated with Neem (300 mg/kg), cold aqueous extract of Plathymenia (100 mg/kg), water (negative control) and insulin (3 IU/day) – positive control; and association between plants. The treatment was performed by orogastric gavage for a period of 28 consecutive days, and weekly weight and daily feed intake were performed. The data were analyzed using ANOVA and Tukey-Kramer’s pos-hoc test, Pearson correlation with a significance level of 5% through the SPSS25.0 software. The results are expressed on average ± EPM. Results: There was lower weight gain in diabetic rats undergoing neem treatment, compared with positive and negative control (-13.00 ± 5.13 vs 150.40 ± 6.80, vs 15.79 ± 7.25, p<0.001); the average daily feed intake was higher in rats treated with neem, compared with positive and negative control (42.00 ± 0.00 vs 26.00 ± 1.26 vs 33.83 ± 0.00; p=0,001). There was no significant difference between the other diabetic groups, except for positive control – insulin. There was also lower weight gain in control animals with Neem, compared with negative control (53.50 ± 4.21 vs 80.00 ± 5.76, p=0.010). The average daily food intake was higher in control animals with Neem compared to negative control (24.00 ± 0.00 vs 15.00 ± 0.00, p=0.029). There was a significant negative correlation between weight gain and food intake in the animals studied (p=0.005). Conclusion: The results allow evaluating a lower weight gain, with higher average daily food intake, in rats treated with Neem, both diabetic and control. This effect may indicate possible use of plant extract in prediabetics, obese diabetics and in the treatment of obesity.
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Mahdavi, Mohammad Ebrahim, Maryam Rezaeian, Homa Zarrinkoob, Mohsen Rezaeian, and Alireza Akbarzadeh. "Effect of a Dichotic Interaural Time Difference Program on Dichotic Listening Deficit of Children with Learning Difficulty." Journal of the American Academy of Audiology 32, no. 05 (May 2021): 295–302. http://dx.doi.org/10.1055/s-0041-1728753.
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Abstract Background Dichotic listening deficit (DLD) is a common sign in children showing learning problem and is identified during auditory processing assessment. A dichotic listening training program was developed in which the weak ear lags behind the strong ear in time and has certain practices for switching attention between the ears and auditory memory. Purpose The aim of the present study was to evaluate the effectiveness of this treatment program on dichotic performance of primary school children showing DLD. Research Design A pre/post clinical trial without control study. Study Sample Twenty-five primary school children, aged 7 to 12 years (mean = 9.3 years), showing DLD. Data Collection and Analysis Several primary schools referred the children with learning difficulty to us. We defined learning difficulty as a score of 2 and lower on a five-point scale in at least two primary school courses in the current semester. The children with DLD participated in listening practices three times a week for 10 weeks, each session lasting for 30 minutes. The practices started with one pair of dichotic digits and ended in practice with sentences. The weak ear lag varied from 100 to 1,000 milliseconds. In the last stage of the practices, the precued and postcued directed response aimed at strengthening auditory memory and switching attention between the ears. The results obtained by the tests of dichotic digits, competing words, and competing sentences before and after the intervention were compared using paired t-test. Hedges's g was calculated as the effect size. Results Comparison of the results of pretraining and those of posttraining revealed that the average dominant ear (DE) and nondominant ear (NDE) scores in dichotic listening tests improved significantly with medium-to-large effect sizes. It was also found that the mean change in the NDE score of the children was significantly greater than that of the DE score for all the tests. Conclusions Dichotic interaural time difference training that employed dichotic lag phenomenon followed by directed response practices significantly improved the DE and the NDE scores of the schoolchildren with DLD.
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Skov-Jeppesen, Sune Moeller, Knud Bonnet Yderstraede, Claus Bistrup, Boyle L. Jensen, Niels Marcussen, Milad Hanna, and Lars Lund. "Low-intensity shockwave therapy in the treatment of diabetic nephropathy: a prospective Phase 1 study." Nephrology Dialysis Transplantation 35, no. 8 (December 22, 2018): 1385–92. http://dx.doi.org/10.1093/ndt/gfy375.
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Abstract Background Low-intensity shockwave therapy (LI-SWT) is suggested as a therapy for promoting tissue regeneration. In pigs, it was recently found that LI-SWT improved renal function after ischaemic injury. Our objectives were to study glomerular filtration rate (GFR) and albuminuria in diabetic nephropathy (DN) after treatment with LI-SWT. The present pilot study reports on the clinical safety of LI-SWT in DN. Methods A total of 14 patients with diabetes mellitus and Stage 3 chronic kidney disease were recruited for this prospective, one-arm Phase 1 study. The patients were treated with six sessions of LI-SWT during a 3-week period. At each session, 3000 shockwaves were applied to each kidney with 0.265 mJ/mm2, extended focal size and 4 Hz. Follow-up visits were performed at 1, 3 and 6 months. Results In general, the treatment was well tolerated. Transient macroscopic haematuria was observed in three patients immediately after LI-SWT. The majority of patients experienced lower back tenderness lasting up to 2 days after treatment. There was no need for analgesic treatment. LI-SWT showed no negative effect on GFR and albuminuria. At baseline, median (interquartile range) GFR was 33.5 mL/min/1.73 m2 (27.8–43.8) compared with 36.0 mL/min/1.73 m2 (27.5–52.0) at 6 months follow-up. In parallel, median albuminuria was 256 mg/24 h (79–619) at baseline and tended to decrease to 137 mg/24 h (41–404) 6 months after LI-SWT. There was no statistical difference between baseline and follow-up results. Conclusions LI-SWT is a safe treatment for DN. Inclusion of more patients is needed to determine whether LI-SWT can improve renal functional outcomes.
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Choi, Jihye, So Jung Oh, and YoonKyoung Lee. "Development of Using Endings (“Eomi”) in Spontaneous Language Samples from 2- to 3-Year-Old Korean Children." Communication Sciences & Disorders 26, no. 3 (September 30, 2021): 545–57. http://dx.doi.org/10.12963/csd.21847.
Повний текст джерелаАнотація:
Objectives: “Eomi” is known as an important grammatical marker in early Korean language development in that it can change the meaning of words, and their function in sentences. The purpose of this study was to investigate Eomi use in spontaneous language samples of young children.Methods: Fifty young children aged 2;6-3;11 participated and were classified into three age groups; late 2-year, early 3-year, and late 3-year groups. Spontaneous language samples were collected during reciprocal book reading procedure with examiners. The number of total Eomi (NTE), and the number of different Eomi (NDE) were counted for overall Eomi and its subcategories; Prefinal Eomi (PE), Connecting Eomi (CE), Transformative Eomi (TE), Sentence closing Eomi (SE). ANOVA and regression analysis were employed for investigating group difference and predicting variables for age, overall NTE and NDE.Results: The overall NTE significantly increased between the late 2-year group and the late 3-year group, and the overall NDE increased significantly between the late 2-yearold group and both 3-year groups. Analysis in Eomi subcategories showed a significant age effect in NTE and NDE of CE and TE. Regression analysis demonstrated that the NDE of TE (57.3%) and CE (6.1%) explained chronological age.Conclusion: Use of Eomi significantly increased during early childhood. The results imply that NDE along with NTE of overall and subcategories of Eomi should be considered in language assessment.
Дисертації з теми "Negative difference effect (NDE)"
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Pereira, Gomes Maurilio. "Investigation on the corrosion mechanisms of pure magnesium and the effect of friction stir welding (FSW) on the corrosion resistance of aluminium alloy 2524-T3." Thesis, Sorbonne université, 2021. http://www.theses.fr/2021SORUS531.
Повний текст джерелаАнотація:
Une étude a été développée concernant le mécanisme de corrosion du magnésium pur. Ce métal a fait l'objet d'un nombre considérable de travaux et, malgré son ubiquité et son histoire, il reste controversé. Ceci est principalement dû à la présence de l'effet de différence négative (NDE), qui augmente la formation d'hydrogène lorsque le magnésium est polarisé sur le domaine anodique. Une analyse détaillée des spectres d'impédance électrochimique obtenus pour l'électrode de Mg lors de son immersion dans une solution de sulfate de sodium a été réalisée. Un modèle a été proposé qui prend en compte la présence de : (i) d'un mince film d'oxyde (MgO) qui a progressivement recouvert la surface de l'électrode de Mg, (ii) de zones sans film où la dissolution du Mg se produit en deux étapes consécutives, (iii) d'une épaisse couche de produits de corrosion (Mg(OH)2), (iv) d'un intermédiaire adsorbé Mg_ads^+ qui est responsable de la réaction chimique permettant d'expliquer le NDE. A partir des analyses des données d'impédance, différents paramètres ont été extraits tels que l'épaisseur du film d'oxyde mince, la résistivité à l'interface métal/film d'oxyde et à l'interface film d'oxyde/électrolyte, la surface active en fonction du temps d'exposition à l'électrolyte, l'épaisseur de la couche épaisse de Mg(OH)2 et les constantes cinétiques des réactions électrochimiquesA parallel study was developed regarding the corrosion mechanism of pure magnesium. It has been the subject of a considerable amount of work, and despite its ubiquity and history, it remains controversial. This is mainly due to the presence of the negative difference effect (NDE), which increases hydrogen formation when the magnesium is biased on the anodic domain. We was performed a detailed analysis of the electrochemical impedance spectra obtained for the Mg electrode during immersion in a sodium sulfate solution. A model was proposed which took into account the presence of: (i) a thin oxide film (MgO) which progressively covered the Mg electrode surface, (ii) film-free areas where the Mg dissolution occurs in two consecutive steps, (iii) a thick layer of corrosion products (Mg(OH)2), (iv) an adsorbed intermediate Mg_ads^+ which is responsible for the chemical reaction allowing the NDE to be explained. From the impedance data analyses, various parameters were extracted such as the thin oxide film thickness, the resistivity at the metal/oxide film interface and at the oxide film/electrolyte interface, the active surface area as a function of the exposure time to the electrolyte, the thickness of the thick Mg(OH)2 layer and the kinetic constants of the electrochemical reactions
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Huang, Chun-Chen, and 黃錞真. "Military Officers Manpower Origin, Gender Difference Affect Negative Affectivity、Co-worker Social Support and Organizational Citizenship Behavior: The Mediating Effect of Job Satisfaction." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/57429742915158108891.
Повний текст джерелаАнотація:
碩士國防管理學院
資源管理研究所
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Because Ministry of National Defence should volunteer battle always on the alert deficiency of officer, near to is it open up wish battle prepare source of officer to devoted to more than ten years, plural officer's manpower enters the channel of using, the result causes the officer of country army population to make up becoming more heterogeneous, increase the difficulty of country's officer's strength resource management. This research adopts the convenient way of sampling, count and grant 470 questionnaires , retrieve 408 effective questionnaires, understand the officer always on the alert and prepare the officer and male officer and female officer to organizational citizenship behavior, whether satisfied , negative affectivity of the work , co-worker social support have a difference to exist. This result of study finds that the female officer's satisfied , negative affectivity of work is the same as male officer with display and organize the degree of citizenship behavior, but the degree of obtaining co-worker social support is relatively low; The officer always on the alert and negative affectivity of preparing the officer are unanimous, but the working sense of achievement of the officer always on the alert is lower than preparing the officer , analyze negative affectivity , co-worker social support can is it influence the officer to display and organizational citizenship behavior to satisfied with through work really finally. This research is via the real inference , find to the social support of the co-worker of work meeting and sex different officers of officer of size of service life on active service really has a difference, and then under the intermediary result that the work meet , influence the officer's negative affectivity , co-worker social support and relation of organizational citizenship behavior, is it can offer Ministry of National Defence to is it spend with what officer consult to enter future to hope , hold officer of country army good manpower continuously in order to Leavey.
Книги з теми "Negative difference effect (NDE)"
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Noordhof, Paul. A Variety of Causes. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780199251469.001.0001.
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Metaphysicians often focus on what is vertically fundamental, appealing to grounding or truth-making, rather than what is horizontally fundamental: what must be common to any metaphysical picture of the universe. There is a case for causation being one such feature. But how should it be characterized? A revised semantics for counterfactuals provides the basis for a new counterfactual analysis of causation that is compatible with Humean supervenience but also appropriate for a non-Humean metaphysical framework. Causes (independently of their competitors) both make the chance of an effect very much greater than its mean background chance in the circumstances and actually influences the probability of the effect in this way at the time at which the effect occurred via a complete causal chain. Causation understood in this way is a non-transitive relation. It is neutral over the metaphysics of causes and effects but allows a natural way for events to be understood as one fundamental type of causation, the other being property causation. Although negative causal statements are true, there are no cases of negative causation. The analysis explains how causation involving substantial processes is only one variety of causation, others include double prevention. It allows for a variety of micro- and macro-properties to be the basis of the difference between cause and effect. Laws are patterns of causation realized in different ways in different metaphysical pictures. The analysis of causation characterizes a horizontally fundamental property whose modal character depends upon its different realizations.
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Githire, Njeri. Immigration, Assimilation, and Conflict. University of Illinois Press, 2017. http://dx.doi.org/10.5406/illinois/9780252038785.003.0003.
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This chapter examines the deployment of counter-incorporative strategies as a means to thwart potentially dangerous elements from entering the eating body. In particular, it examines how, through the language of disease and contamination that proliferates in the realm of immigration and its effect on culture, select national cultures are portrayed as under attack from foreigners and their filthy, debased bodies. Marked with cannibalism as the ultimate expression of savagery and human degradation, these bodies evoke anxiety and deep-seated fear of extinction in the national consciousness. Focusing on select texts by Edwidge Danticat, Andrea Levy, and Gisèle Pineau—works that have become entrenched in the canon of Caribbean women's writings thanks to their framing of food and eating as symbolic practices in diasporic identity formation—the chapter analyzes the national body as an ingesting, digesting, and excreting organism. It explores the twin phenomena of cannibalism, that is: taking in difference in order to neutralize its negative impacton the receiving body, and anthropemy—the elimination of sickening symptoms by vomiting the ingested foreign body.
Частини книг з теми "Negative difference effect (NDE)"
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Téot, Luc, Sergiu Fluieraru, and Christian Herlin. "Suture Edge Tension Control Technologies for Scar Improvement." In Textbook on Scar Management, 497–502. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-44766-3_57.
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AbstractMechanotherapy of postoperative scarring is considered an effective measure to prevent pathological scars. Tension increases suture line enlargement, opening the way to infection. Several options have been proposed since decades and are currently used in practice, from adhesive sutures to adhesive dressings, reapproximation devices, and postoperative negative pressure. Closed incision negative pressure therapy (ciNPT) was recently proposed in at-risk patients, showing a significant difference in prevention of infection. These technologies offer a double effect of mechanical stabilization and aspiration of exudates and have recently been extended to different clinical indications. This chapter describes the recently developed technologies to diminish scar enlargement on a suture line and to prevent infection after extensive surgical procedures in thoracic, abdominal, plastic and orthopedic surgery.
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Olusegun, Aroyeun Shamsideen, Adegoke Gabriel Olanrewaju, and Varga Janos. "Reduction of the Negative Effect of Ochratoxin A on the Organs of Rats Fed Ochratoxin A Contaminated Chocolate by the Spice Aframomum Danielli." In Sharing Knowledge Making a Difference: The Role of International Scientific Cooperation., 433–48. WASD, 2011. http://dx.doi.org/10.47556/b.outlook2011.9.25.
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Stein, Michael D., and Sandro Galea. "The Partisan Divide over a Soda Tax." In Pained, 39–42. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780197510384.003.0013.
Повний текст джерелаАнотація:
This chapter looks at research which examined public health messaging in the context of partisan responses to a public health initiative—a sugary drink tax. The tax is controversial, facing opposition fueled and funded by the soda industry. The study then measured the effect of three messaging tactics. The pro-tax approach conveyed the message that sugary drinks should be taxed because they contribute to obesity. The two-sided message stated that sugary drinks cause obesity, but taxes will not help to reduce it. The refutation message said that soda companies are promoting anti-tax sentiment for their own gain, even though soda contributes to obesity. The refutation message resulted in the largest difference of opinion about soda taxes for Democrats and Independents, in contrast to Republicans—who were not influenced by negative messaging about company motives. No significant political party difference was observed for the pro-tax message, and the two-sided message reduced support from all parties. The chapter then suggests that perhaps it is time to look outside the conventional arguments when policymakers attempt to pass soda taxes.
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Cheng, Yiying. "Valuing and Analyzing Bonds with Embedded Options." In Debt Markets and Investments, 453–76. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190877439.003.0025.
Повний текст джерелаАнотація:
This chapter introduces the analysis and valuation of bonds with embedded options. For callable bonds, it discusses their unique reinvestment risk and negative convexity. For both callable bonds and puttable bonds, the chapter introduces two additional measures to gauge their risk: yield-to-call and yield-to-put, respectively. The chapter reviews the application of the spot rate curve in bond valuation and introduces the Z-spread to measure bond-specific risk more accurately. To model interest rate risk, the chapter builds a binomial interest rate model and calibrates it with on-the-run Treasury issues. The option-adjusted-spread (OAS) is introduced to measure the bond-specific risk excluding the option effect. The difference between Z-spread and OAS represents the option effect. Common measures of convertible bond risk and value are discussed including the possibility of valuating a convertible bond using option-pricing models and its drawbacks.
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Mayo, Marjorie. "Public policies to promote community cohesion." In Changing Communities. Policy Press, 2017. http://dx.doi.org/10.1332/policypress/9781447329312.003.0008.
Повний текст джерелаАнотація:
This chapter focuses upon strategies to respond to the darker sides of ‘community’, the more exclusionary sides, and the conflicts that can so easily be exacerbated within as well as between communities. Public policies have addressed these issues in more – or less- successful ways. Public policies can backfire, just as they can have the effect of reinforcing negative stereotypes of the ‘other’. This criticism has been applied to policies to promote community cohesion via ‘Prevent’ programmes against violent extremism, for example, in the context of the so-called ‘War on Terror’. The chapter concludes by focussing upon policy interventions that have been making a difference more constructively, supporting communities to identify shared interests, negotiating differences and developing solidarity in the process.
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Raffa, Robert B. "Benzodiazepine Receptors in the Periphery." In The Benzodiazepines Crisis, 81–96. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780197517277.003.0006.
Повний текст джерелаАнотація:
The benzodiazepines are almost universally thought to produce one and only one pharmacologic effect: positive allosteric modulation of GABAA receptors located in the brain. This results in an increased Cl−ion influx, greater negative transmembrane potential difference, and neurons that are less likely to fire in response to anxiety-producing stimulation. Unfortunately, the simplicity and success of this mono-target belief has distracted researchers and clinicians from studying and appreciating their other pharmacology. A glaring example is the general lack of awareness of the peripheral benzodiazepine receptor. The peripheral benzodiazepine receptor alters mitochondrial function (energy supply), cholesterol transport, and immune function. A patient who is on long-term benzodiazepine therapy (or withdrawing from them) will have these sites affected, just as are the sites located in the brain. One can easily imagine that the adverse effects associated with the peripheral sites would be fundamental, varied, and potentially profound—involving lack of energy, altered cholesterol metabolism, and aberrant immune function.
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Moon, Woojin. "Elections and Electoral Systems." In The Oxford Handbook of South Korean Politics. Oxford University Press, 2022. http://dx.doi.org/10.1093/oxfordhb/9780192894045.013.16.
Повний текст джерелаАнотація:
Abstract This chapter explains how the electoral system in South Korea has formed into a two-party-dominated system and identifies the elements that prevent a third party from winning seat shares proportional to its vote share. The chapter discusses the features that characterize political parties’ campaign strategies and the voting behaviour of South Korean citizens. Candidates pursue personal votes by focusing on negative campaigning and advertising their valences. This chapter also identifies two major position issues over which political parties compete and citizens make voting decisions. Although redistributive issues have recently become more salient, electoral competition has long revolved around inter-Korean issues. Citizens’ socio-economic statuses only have a meagre effect on their partisan support. Instead, citizens’ political attitudes have been formed differently across generations, as they have been exposed to different levels of anti-communism. Finally, the chapter explains the variation in regional voting in terms of party system polarization. As the ideological difference between parties has decreased, regional voting has intensified.
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Prehoda, Kenneth E., and John L. Markley. "Use of Partial Molar Volumes of Model Compounds in the Interpretation of High-Pressure Effects on Proteins." In High Pressure Effects in Molecular Biophysics and Enzymology. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195097221.003.0006.
Повний текст джерелаАнотація:
The transfer of liquid hydrocarbons into water is accompanied by a large decrease in volume at 25 °C and atmospheric pressure, with typical values for ΔV°tr of — 2.0 ml mol methylene−1. Considering the large amount of apolar surface that is exposed when a globular protein unfolds, the hydrocarbon transfer results imply that the change in volume accompanying the unfolding process (ΔV°obs) should be highly negative under these conditions. However, experimental data on the pressure denaturation of proteins typically yield relatively small values of ΔV°obs at atmospheric pressure and 25 °C. We analyze this apparent inconsistency in terms of a simple thermodynamic dissection of the partial molar volume. This approach allows the volume effects that result from solute-solvent interactions to be determined from experimental partial molar volumes. The use of absolute quantities (partial molar volumes) circumvents assumptions associated with the use of results from transfer experiments. An important finding is that hydration of apolar species is less dense than bulk water. This discovery leads to the conclusion that the contribution to ΔV°obs for protein unfolding from the hydration of apolar surfaces is highly positive, contrary to predictions based on transfer data. Further, hydration of polar surfaces makes a positive contribution to ΔV°obs. The large, positive term from the differential hydration of the folded and unfolded states is compensated by the difference in free volume of the protein in the two states. This finding provides a new framework for interpreting pressure effects on macromolecules. The full characterization of a macromolecular system requires knowledge of the effect of pressure on the system. The thermodynamic information obtained from using pressure as a perturbation is a volume change for the particular reaction being studied. The observed volume change, ΔV°obs, for protein unfolding may provide insight into the mechanisms that determine the three-dimensional structure of the folded state. Pressure denaturation experiments have been demonstrated for a number of proteins, including ribonuclease A (Gill & Glogovsky, 1965; Brandts et al., 1970), chymotrypsinogen (Hawley, 1971), metmyoglobin (Zipp & Kauzmann, 1973), and, more recently, lysozyme (Samarasinghe et al., 1992) and staphylococcal nuclease (Royer et al., 1993).
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Li, C. B. "Electric Conductance." In Chemistry of Variable Charge Soils. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195097450.003.0011.
Повний текст джерелаАнотація:
The migration of colloidal soil particles in an applied electric field has been discussed in Chapter 7. Soil particles carrying electric charges invariably adsorb equivalent amounts of ions of the opposite charge. Generally there is a certain amount of free ions present in soil solution. When an electric field is applied to a soil system, a phenomenon known as electric conductance occurs. As in the case for electrolyte solutions, soil particles and various ions interact with one another during their migration, and these interactions can affect the electric conductance of the system. Variable charge soils carry both positive and negative surface charges, and it can be expected that their interactions with various ions would be rather complicated during conductance. On the other hand, this makes the measurement of electric conductance an effective means in elucidating the mechanisms of interactions between variable charge soils and ions. Both direct-current (DC) electric fields and alternating-current (AC) electric fields can induce the migration of charged particles. In the latter case, the migration of these particles should be related to the frequency of the applied AC electric field. Therefore, in this chapter, after describing the principles of electric conductance of ions and colloids and the factors that affect the conductance of a soil, emphasis shall be placed on the interaction between variable charge soils and various ions as reflected by the frequency effect in electric conductance. For a colloidal suspension, the electric conductance may be regarded as the contribution of conductances of both charged colloidal particles and ions. These two parts may be called the electric conductance of colloidal panicles and the electric conductance of ions, respectively. However, in actual cases it is difficult to distinguish between these two parts. Therefore, it is a general practice to distinguish the electric conductance as that caused by colloidal particles plus their counterions from that caused by ions of the free solution. These may be called electric conductance of the colloid and electric conductance of the free solution. The former conductance is the difference between the electric conductance of the suspension and that of the free solution.
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"Radioactive Pollution." In Environmental Toxicology, edited by Sigmund F. Zakrzewski. Oxford University Press, 2002. http://dx.doi.org/10.1093/oso/9780195148114.003.0018.
Повний текст джерелаАнотація:
Radiation that, on passage through matter, produces ions by knocking electrons out of their orbits is called ionizing radiation. This radiation is produced through decomposition of unstable, naturally occurring or synthetic elements referred to as radionuclides. The four types of radiation are ∝-particles, β-particles, γ-rays, and neutrons. The ∝-particles have a mass of two protons and two neutrons and a charge of +2; β -particles are electrons with a mass of 0.00055 atomic mass unit (amu) and a charge of –1; γ -rays and X-rays are high-frequency electromagnetic waves with no mass and no charge. The difference between γ -rays and X-rays is that γ -rays occur naturally, whereas X-rays are generated. In addition, γ -rays are of higher frequency than X-rays. Release of an ∝ -particle leads to the formation of a daughter element with an atomic number 2 units lower and an atomic weight 4 units lower than that of the parent nuclide. Similarly, release of a β -particle from the nucleus causes conversion of a neutron to a proton, producing a daughter element with the same atomic weight as the parent nuclide but with its atomic number increased by 1 unit. Neutron radiation does not occur naturally and is released only from synthetic radionuclides. Neutrons, which have no charge, are formed from protons. This conversion is accompanied by the release of an orbital electron from the atom. Neutrons produce ions indirectly, by collisions with hydrogen atoms. The impact knocks out protons, which in turn produce ions on passage through matter. Capture of a neutron forms an isotope of the parent nuclide with its atomic weight increased by 1 unit. The mode of action of particles (∝ and β ) varies from that of photons (γ - and X-rays). When ∝- or β -particles travel through matter, their electric charges (positive or negative) cause ionization of the atoms in the matter. This is called a direct effect. Whereas the track of ∝- particles is short and straight, β -particles scatter, frequently producing a wavy track. Gamma- and X-rays act indirectly.
Тези доповідей конференцій з теми "Negative difference effect (NDE)"
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Yining, Liu, Wang Renze, Yang Yapeng, Zhang Jiangang, Wang Ning, Feng Zongyang, Jia Linsheng, and Liang Boning. "The Choice of MOSFET Manufacturing Technique Used in Emergency Response Robot." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16222.
Повний текст джерелаАнотація:
Abstract For the aim of helping the development of robots used in Radiological Emergency Planning and Preparedness, the Total Ionizing Dose (TID) effects on the threshold voltage shift (ΔVth) of different kinds of Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) with different geometry and different scaling technology was compared. The different gate width and length dependent between bulk Complementary Metal-Oxide-Semiconductor Transistor (CMOS) process and nanowire (NW) MOSFET as well as higher and lower technology node is noticed. The reason of this difference is explained from the aspects of Radiation Induced Narrow channel effect (RINCE) and Radiation Induced Short channel effect (RISCE). It is found that some studies in recent years have corrected the influence of negative bias temperature instability (NBTI) when considering radiation effects. The TID effects on ΔVth of several kinds of new devices such as MOSFETs with new layout geometry as well as Ge-channel and GaN channel MOSFETs are described which can be investigated more deeply.
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Duarte, Gabriel Jonas, Tamara Arruda Pereira, Erik Jhones Nascimento, Diego Mesquita, and Amauri Holanda Souza Junior. "How do loss functions impact the performance of graph neural networks?" In Congresso Brasileiro de Inteligência Computacional. SBIC, 2021. http://dx.doi.org/10.21528/cbic2021-161.
Повний текст джерелаАнотація:
Graph neural networks (GNNs) have become the de facto approach for supervised learning on graph data.To train these networks, most practitioners employ the categorical cross-entropy (CE) loss. We can attribute this largely to the probabilistic interpretability of models trained using CE, since it corresponds to the negative log of the categorical/softmax likelihood.We can attribute this largely to the probabilistic interpretation of CE, since it corresponds to the negative log of the categorical/softmax likelihood.Nonetheless, recent works have shown that deep learning models can benefit from adopting other loss functions. For instance, neural networks trained with symmetric losses (e.g., mean absolute error) are robust to label noise. Nonetheless, loss functions are a modeling choice and other training criteria can be employed — e.g., hinge loss and mean absolute error (MAE). Perhaps surprisingly, the effect of using different losses on GNNs has not been explored. In this preliminary work, we gauge the impact of different loss functions to the performance of GNNs for node classification under i) noisy labels and ii) different sample sizes. In contrast to findings on Euclidean domains, our results for GNNs show that there is no significant difference between models trained with CE and other classical loss functions on both aforementioned scenarios.
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Shaffer, Brendan, and Jacob Brouwer. "Dynamic Model for Understanding Spatial Temperature and Species Distributions in Internal-Reforming Solid Oxide Fuel Cells." In ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2009. http://dx.doi.org/10.1115/fuelcell2009-85095.
Повний текст джерелаАнотація:
Direct internal reformation of methane in solid oxide fuel cells (SOFCs) leads to two major performance and longevity challenges: thermal stresses in the cell due to large temperature gradients and coke formation on the anode. A simplified quasi-two-dimensional direct internal reformation SOFC (DIR-SOFC) dynamic model was developed for investigation of the effects of various parameters and assumptions on the temperature gradients across the cell. The model consists of 64 nodes each of which contains four control volumes: the positive electrode, electrolyte, negative electrode (PEN); interconnect; anode gas; and cathode gas. Within each node the corresponding conservation, chemical, and electrochemical reaction equations are solved. The model simulates the counterflow configuration since previous research [8] has shown this configuration to yield the smallest temperature differentials. Steady state simulations revealed several results where the temperature difference across the cell was considerably affected by operating and cell design parameters. Increasing the performance of the cell through modifications to the electrochemical model to simulate modern cell performance produced significant changes in the cell temperature differential. Improved cell performance led to a maximum increase in the temperature differential across the cell of 31 K. An increase in the interconnect thickness also exhibits a considerable reduction in the temperature difference across the PEN. In particular, increasing the interconnect thickness from 3.5 to 4.5 mm can achieve about a 50 K reduction in the cross cell temperature difference. Variation of other physical parameters such as the thermal conductivity of the interconnect and the rib width also showed an effect on the temperature distribution. The sensitivity of temperature distribution to the adiabatic assumption was also performed and results showed a considerable effect near the fuel and air inlets. This resulted in severe temperature gradients approaching 160 K/cm.
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Saisubramanian, Sandhya, Ece Kamar, and Shlomo Zilberstein. "A Multi-Objective Approach to Mitigate Negative Side Effects." In Twenty-Ninth International Joint Conference on Artificial Intelligence and Seventeenth Pacific Rim International Conference on Artificial Intelligence {IJCAI-PRICAI-20}. California: International Joint Conferences on Artificial Intelligence Organization, 2020. http://dx.doi.org/10.24963/ijcai.2020/50.
Повний текст джерелаАнотація:
Agents operating in unstructured environments often create negative side effects (NSE) that may not be easy to identify at design time. We examine how various forms of human feedback or autonomous exploration can be used to learn a penalty function associated with NSE during system deployment. We formulate the problem of mitigating the impact of NSE as a multi-objective Markov decision process with lexicographic reward preferences and slack. The slack denotes the maximum deviation from an optimal policy with respect to the agent's primary objective allowed in order to mitigate NSE as a secondary objective. Empirical evaluation of our approach shows that the proposed framework can successfully mitigate NSE and that different feedback mechanisms introduce different biases, which influence the identification of NSE.
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Tian, Yiran, and Yanfeng Shen. "Selective Lamb Mode Transmission Enabled by Local Resonance Based Ultrasonic Metamaterial." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-10872.
Повний текст джерелаАнотація:
Abstract In this study, a kind of elastic metamaterial substructure was designed for the selective mode filtering and transmission of symmetric and antisymmetric elastic waves. It is composed of double-sided aluminum-lead composite cylinders arranged in a periodic pattern bounded on an aluminum plate. The band structure of elastic metamaterial unit cell is numerically investigated using the modal analysis of a finite element model (FEM) by treating a unit microstructural cell with the Bloch-Floquet boundary condition. Through analyzing the vibration modes of the unit cell, a complete antisymmetric wave bandgap and a complete symmetric wave bandgap can be formed in different frequency ranges. Considering the geometric complexity of the designed substructure, the dynamic effective mass density of the proposed metamaterial unit cell is calculated by considering the structure as a homogeneous medium under the sub-wavelength requirement. The negative effective mass density behavior for in-plane and out-of-plane plate modes will be presented to verify the bandgap effect of different wave modes. A FEM harmonic analysis is further conducted to obtain the spectral response of a chain model and explore the mode filtering efficiency. Finally, a coupled field transient dynamic FEM is carried out to acquire the dynamic response of the structure. The frequency-wavenumber analysis demonstrates the successful achievement of model filtering behavior. The proposed selective mode transmission control methodology possesses great potential in future SHM and NDE applications. A case study for S0 mode conversion to SH0 mode using a different metamaterial unit cell is exhibited to illustrate other wave control capabilities. The paper finishes with summary, concluding remarks, and suggestions for future work.
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Lee, Kitae, Junil Lee, Sihyun Kim, Soyoun Kim, Munhyeon Kim, Sangwan Kim, and Byung-Gook Park. "Analysis on Fully Depleted Negative Capacitance Field-Effect Transistor (NCFET) Based on Electrostatic Potential Difference." In 2019 Electron Devices Technology and Manufacturing Conference (EDTM). IEEE, 2019. http://dx.doi.org/10.1109/edtm.2019.8731124.
Повний текст джерела
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Lee, Ho Young, and Yuri M. Shkel. "Self-Sensing of Stresses and Strains Through the Dielectrostriction Effect in Composites." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15727.
Повний текст джерелаАнотація:
Any dielectric material would vary its dielectric properties with deformation. By measuring these variations one could monitor stresses or strains with no mechanical interface with a load-bearing member. This effect, called dielectrostriction, can be formulated as a linear relation between the stress/strain and the dielectric response of a material. A planar capacitor on a rigid substrate is utilized to monitor the dielectrostriction effect. A rosette of such sensors can be located on the surface or embedded in the monitored part. A four-sensor rosette measures principal directions and difference of principal strains. Overall, this sensing technology shows a good potential for Non-Destructive Evaluation (NDE) and structural health monitoring of composite materials. This work provides theoretical background and experimental study of dielectrostriction response in polycarbonate, polyethylene, acrylic, and carbon nanotube composite materials.
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Lian, Bo, Xiaocheng Zhu, and Zhaohui Du. "Mistuning Effects on Aero-Elastic Stability of Civil Transonic Fan Blades." In ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-80613.
Повний текст джерелаАнотація:
Abstract Flutter seriously affects the safety and reliability of aeroengine. The blade mistuning is inevitable due to machining error and service wear, which has a significant influence on flutter stability. In this paper, the eigenvalue method is used to calculate the aerodynamic damping of transonic fan blades of civil aviation engine at different nodal diameters (NDs) and structural modes. The results show that under the design condition, the first three structural modes of the blade are aero-elastic stable for each ND, and the aerodynamic damping gets the minimum at ND1 for the first bending mode. As the back pressure deviates from design condition towards stall, the aerodynamic damping obviously decrease and even negative aerodynamic damping occurs at normalized mass flow rate of 0.930. Six kinds of mistuning patterns are considered based on the eigenvalue method, divided into two categories: structural mistuning and aerodynamic mistuning, where structural mistuning includes alternate mistuning, sinusoidal mistuning and random mistuning. The alternate mistuning has better improvement on flutter suppression than the sinusoidal mistuning with the same frequency offset, though further increasing the amount of mistuning cannot provide extra aero-damping when the frequency offset reaches a critical value of 7%. For the aerodynamic mistuning, the improvement of aero-damping is limited in comparison with the structural mistuning, especially for the random mistuning through Monte Carlo simulations. Based on the analysis of eigenvectors, the single blade aerodynamic mistuning breaks the periodic pattern in travelling wave mode, which tends to make the aero-elastic systems stable. While the symmetry group mistuning maintains the periodicity and destabilizes the aero-elastic system.
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Qiu, Hongyuan, and Jianming Yang. "Stochastic and Deterministic Vibration Analysis on Drill-String With Finite Element Method." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62563.
Повний текст джерелаАнотація:
Using Euler-Bernoulli beam theory, a finite element model with six degrees of freedom per node is developed for a drill-string assembly. The drill-string is driven by a DC motor on the top and is subjected to distributed loads due to its own weight as well as bit/formation interaction. The model is axial-torsional, lateral-torsional coupled. Under deterministic excitations, the model captures stick-slip behavior in drilling operation. Analysis on its negative effect on drilling performance are made, and potential mitigation measures are also discussed. In random model, the excitations to the drill-bit are modeled as combination of deterministic and random components. Monte Carlo (MC) simulation is employed to obtain the statistics of the response. Two cases of random excitation with different intensities are investigated. The results from MC simulation are compared against that from deterministic case.
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Jeong, Jae-Ho, and Soo-Hyun Kim. "Investigation of Flatback Airfoil Effect in the Wind Turbine Blade." In ASME/JSME/KSME 2015 Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/ajkfluids2015-09806.
Повний текст джерелаАнотація:
The flatback airfoil effect in the inboard region of large wind turbine blade has been investigated by numerical analysis. Complicated flow phenomena in the wind turbine blade were captured by Reynolds-averaged Navier-Stokes flow simulation (RANS) with SST (Shear Stress Transport) turbulence model. The inboard region of the blade without the flatback airfoils is dominated by the separated vortex. The separated vortex starts to be formed near the blade mid-chord. The separated vortex core is generated by the large pressure difference in the blade inboard trailing edge region. The separated vortex grows nearly in the outboard direction, which is so-called secondary flow on the blade surface. The flatback airfoils are designed, and applied to the wind turbine inboard region. The scale of the separated vortex can be decreased, and the blade performance enhanced up to nearly 6% in the flatback airfoil region. However, the blade with large wake thickness due to the flatback airfoil has a negative impact on the aerodynamic noise. Regardless of the flatback airfoils, the tip vortex core of the outboard region is formed on the suction surface leading edge, and strongly rolled-up by the pressure surface boundary layers due to the large pressure difference between the suction surface and the pressure surface in the blade tip region. This remarkably strong tip vortex develops downstream, and rakes up the blade trailing edge boundary layer with low energy.
Звіти організацій з теми "Negative difference effect (NDE)"
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Ricciulli-Marín, Diana. The Fiscal Cost of Conflict: Evidence from La Violencia in Colombia. Banco de la República de Colombia, December 2020. http://dx.doi.org/10.32468/chee.53.
Повний текст джерелаАнотація:
This paper studies the effect of internal conflict on local fiscal capacity using evidence from Colombia’s political conflict in the mid-20th century, better known as La Violencia. Following a difference-in-differences strategy, I find that internal conflict has negative long-term consequences in local fiscal capacity. More precisely, municipalities affected by La Violencia experienced an average reduction of 10.3% in their tax revenue and a fall of 2.8 percentage points on their ratio of taxes to total revenue. Effects lasted for more than a decade and are only partially explained by a population and economic activity downturn. These results are consistent with previous evidence indicating a negative effect of violence on tax collection efficiency at the local level.
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Datta, Sandip, and Geeta Kingdon. Class Size and Learning: Has India Spent Too Much on Reducing Class Size? Research on Improving Systems of Education (RISE), January 2021. http://dx.doi.org/10.35489/bsg-rise-wp_2021/059.
Повний текст джерелаАнотація:
This paper examines the efficacy of class-size reductions as a strategy to improve pupils’ learning outcomes in India. It uses a credible identification strategy to address the endogeneity of class-size, by relating the difference in a student’s achievement score across subjects to the difference in his/her class size across subjects. Pupil fixed effects estimation shows a relationship between class size and student achievement which is roughly flat or non-decreasing for a large range of class sizes from 27 to 51, with a negative effect on learning outcomes occurring only after class size increases beyond 51 pupils. The class-size effect varies by gender and by subject-stream. The fact that up to a class-size of roughly 40 in science subjects and roughly 50 in non-science subjects, there is no reduction in pupil learning as class size increases, implies that there is no learning gain from reducing class size below 40 in science and below 50 in non-science. This has important policy implications for pupil teacher ratios (PTRs) and thus for teacher appointments in India, based on considerations of cost-effectiveness. When generalised, our findings suggest that India experienced a value-subtraction from spending on reducing class-sizes, and that the US$3.6 billion it spent in 2017-18 on the salaries of 0.4 million new teachers appointed between 2010 and 2017 was wasteful spending rather than an investment in improving learning. We show that India could save US$ 19.4 billion (Rupees 1,45,000 crore in Indian currency) per annum by increasing PTR from its current 22.8 to 40, without any reduction in pupil learning.
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Seginer, Ido, Daniel H. Willits, Michael Raviv, and Mary M. Peet. Transpirational Cooling of Greenhouse Crops. United States Department of Agriculture, March 2000. http://dx.doi.org/10.32747/2000.7573072.bard.
Повний текст джерелаАнотація:
Background Transplanting vegetable seedlings to final spacing in the greenhouse is common practice. At the time of transplanting, the transpiring leaf area is a small fraction of the ground area and its cooling effect is rather limited. A preliminary modeling study suggested that if water supply from root to canopy is not limiting, a sparse crop could maintain about the same canopy temperature as a mature crop, at the expense of a considerably higher transpiration flux per leaf (and root) area. The objectives of this project were (1) to test the predictions of the model, (2) to select suitable cooling methods, and (3) to compare the drought resistance of differently prepared seedlings. Procedure Plants were grown in several configurations in high heat load environments, which were moderated by various environmental control methods. The difference between the three experimental locations was mainly in terms of scale, age of plants, and environmental control. Young potted plants were tested for a few days in small growth chambers at Technion and Newe Ya'ar. At NCSU, tomato plants of different ages and planting densities were compared over a whole growing season under conditions similar to commercial greenhouses. Results Effect of spacing: Densely spaced plants transpired less per plant and more per unit ground area than sparsely spaced plants. The canopy temperature of the densely spaced plants was lower. Air temperature was lower and humidity higher in the compartments with the densely spaced plants. The difference between species is mainly in the canopy-to-air Bowen ratio, which is positive for pepper and negative for tomato. Effect of cooling methods: Ventilation and evaporative pad cooling were found to be effective and synergitic. Air mixing turned out to be very ineffective, indicating that the canopy-to-air transfer coefficient is not the limiting factor in the ventilation process. Shading and misting, both affecting the leaf temperature directly, proved to be very effective canopy cooling methods. However, in view of their side effects, they should only be considered as emergency measures. On-line measures of stress: Chlorophyll fluorescence was shown to accurately predict photosynthesis. This is potentially useful as a rapid, non-contact way of assessing canopy heat stress. Normalized canopy temperature and transpiration rate were shown to correlate with water stress. Drought resistance of seedlings: Comparison between normal seedlings and partially defoliated ones, all subjected to prolonged drought, indicated that removing about half of the lowermost leaves prior to transplanting, may facilitate adjustment to the more stressful conditions in the greenhouse. Implications The results of this experimental study may lead to: (1) An improved model for a sparse canopy in a greenhouse. (2) A better ventilation design procedure utilizing improved estimates of the evaporation coefficient for different species and plant configurations. (3) A test for the stress resistance of transplants.
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Choudhary, Ruplal, Victor Rodov, Punit Kohli, Elena Poverenov, John Haddock, and Moshe Shemesh. Antimicrobial functionalized nanoparticles for enhancing food safety and quality. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7598156.bard.
Повний текст джерелаАнотація:
Original objectives The general goal of the project was to utilize the bactericidal potential of curcumin- functionalizednanostructures (CFN) for reinforcement of food safety by developing active antimicrobial food-contact surfaces. In order to reach the goal, the following secondary tasks were pursued: (a) further enhancement of the CFN activity based on understanding their mode of action; (b) preparing efficient antimicrobial surfaces, investigating and optimizing their performance; (c) testing the efficacy of the antimicrobial surfaces in real food trials. Background to the topic The project dealt with reducing microbial food spoilage and safety hazards. Cross-contamination through food-contact surfaces is one of the major safety concerns, aggravated by bacterial biofilm formation. The project implemented nanotech methods to develop novel antimicrobial food-contact materials based on natural compounds. Food-grade phenylpropanoidcurcumin was chosen as the most promising active principle for this research. Major conclusions, solutions, achievements In agreement with the original plan, the following research tasks were performed. Optimization of particles structure and composition. Three types of curcumin-functionalizednanostructures were developed and tested: liposome-type polydiacetylenenanovesicles, surface- stabilized nanoparticles and methyl-β-cyclodextrin inclusion complexes (MBCD). The three types had similar minimal inhibitory concentration but different mode of action. Nanovesicles and inclusion complexes were bactericidal while the nanoparticlesbacteriostatic. The difference might be due to different paths of curcumin penetration into bacterial cell. Enhancing the antimicrobial efficacy of CFN by photosensitization. Light exposure strengthened the bactericidal efficacy of curcumin-MBCD inclusion complexes approximately three-fold and enhanced the bacterial death on curcumin-coated plastic surfaces. Investigating the mode of action of CFN. Toxicoproteomic study revealed oxidative stress in curcumin-treated cells of E. coli. In the dark, this effect was alleviated by cellular adaptive responses. Under light, the enhanced ROS burst overrode the cellular adaptive mechanisms, disrupted the iron metabolism and synthesis of Fe-S clusters, eventually leading to cell death. Developing industrially-feasible methods of binding CFN to food-contact surfaces. CFN binding methods were developed for various substrates: covalent binding (binding nanovesicles to glass, plastic and metal), sonochemical impregnation (binding nanoparticles to plastics) and electrostatic layer-by-layer coating (binding inclusion complexes to glass and plastics). Investigating the performance of CFN-coated surfaces. Flexible and rigid plastic materials and glass coated with CFN demonstrated bactericidal activity towards Gram-negative (E. coli) and Gram-positive (Bac. cereus) bacteria. In addition, CFN-impregnated plastic material inhibited bacterial attachment and biofilm development. Testing the efficacy of CFN in food preservation trials. Efficient cold pasteurization of tender coconut water inoculated with E. coli and Listeriamonocytogeneswas performed by circulation through a column filled with CFN-coated glass beads. Combination of curcumin coating with blue light prevented bacterial cross contamination of fresh-cut melons through plastic surfaces contaminated with E. coli or Bac. licheniformis. Furthermore, coating of strawberries with CFN reduced fruit spoilage during simulated transportation extending the shelf life by 2-3 days. Implications, both scientific and agricultural BARD Report - Project4680 Page 2 of 17 Antimicrobial food-contact nanomaterials based on natural active principles will preserve food quality and ensure safety. Understanding mode of antimicrobial action of curcumin will allow enhancing its dark efficacy, e.g. by targeting the microbial cellular adaptation mechanisms.
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ON FIELD-MEASURED VERTICAL TEMPERATURE GRADIENT OF BOX GIRDER IN STEEL BRIDGES. The Hong Kong Institute of Steel Construction, August 2022. http://dx.doi.org/10.18057/icass2020.p.320.
Повний текст джерелаАнотація:
To investigate distribution of the vertical temperature gradient of a closed steel box girder under solar radiation, specifications in four major codes on the vertical temperature gradient of a main girder or steel box girder in China and other countries are first compared. Then, temperature measurement is carried out inside a steel box girder bridge. It was found that under the effect of hot weather and strong solar radiation, the temperature rose rapidly on the deck overlay and reached its maximum at around 14:00, while the maximum temperature of the deck was recorded at around 16:00. Notable temperature differences between the deck and bottom plate occurred from 14:00 to 18:00, with the maximum value of 16.8℃ presented at around 14:30. It was also found that the positive vertical temperature gradient showed nonlinear distribution, and the girder top had a larger positive temperature difference but a minor negative temperature difference. A suggested pattern of vertical temperature gradient was fitted using a four-broken-line, which is in line with specification in the Eurocode 1.