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Procédés de Vaporisation et Combustion des Alcools et de l'Acétone-Butanol-Ethanol (ABE) Mélangés au n-dodécane dans des Conditions de Haute-Pression et Haute-Température : Application au Moteur à allumage par compression
No full textThe growing concern in recent decades, linked to the depletion of oil resources and global warming by greenhouse gases has increased the interest of butanol as an alternative fuel in the transport sector. However, the low yield of production and separation processes still prevents its commercialization as a fuel. Therefore, the intermediate fermentation mixture of butanol production, Acetone-Butanol-Ethanol (ABE), is increasingly considered as a potential alternative fuel because of its similar properties to butanol and its advantages in terms of the energy and cost in the separation process.The context of this work aims to study the impact of fuel properties on the spray and combustion processes of ABE mixture and alcohol fuels, blended with the diesel surrogate fuel, n-dodecane, in different volume ratio from 20% to 50%. A new combustion chamber called "New One Shot Engine," was designed and developed to reach the high-pressure and high temperatureconditions of "Spray-A" (60 bar, 800-900 K and 22.8 kg/m³) defined by the Engine Combustion Network (ECN).The macroscopic spray and combustion parameters were characterized by using the several optical techniques (extinction,Schlieren, chemiluminescence of OH*) under non-reactive (pure Nitrogen) and reactive (15% of oxygen) conditions. These experimental results not only made it possible to study the molecular oxygen impact and provide a new accurate database,but also to affirm the possibility of using ABE up to 20% by volume in compression-ignition engines, as its spray and combustion characteristics similar to conventional diesel fuel.La préoccupation de plus en plus importante ces dernières décennies, liée à l’épuisement des ressources pétrolières et au réchauffement climatique par les gaz à effet de serre a accentué l’intérêt du butanol comme carburant alternatif dans le secteur des transports grâce à ses propriétés adaptées pour le moteur à allumage par compression. Cependant, le faible rendement des procédés de production et de séparation empêche encore sa commercialisation en tant que carburant. C’est pourquoi le mélange de fermentation intermédiaire de la production de butanol, Acétone-Butanol-Ethanol(ABE), est de plus en plus considéré comme un carburant alternatif potentiel en raison de ses propriétés similaires au butanol et de ses avantages quant à son cout énergétique pour sa fabrication.Dans ce cadre, ce travail a pour objectif d’étudier l’impact des propriétés de différents mélanges d’ABE et n-dodécane en comparaison avec des mélanges d’alcools (éthanol et butanol) sur le processus de pulvérisation et de combustion et ce,pour différentes proportions en volume allant de 20% à 50%. Pour cela, une nouvelle chambre de combustion appelée"New One Shot Engine ", a été réalisée et utilisée car les conditions haute pression et haute température de "Spray-A" (60bars, 800-900 K et 22,8 kg/m³) définies par le réseau Engine Combustion network (ECN) peuvent être atteintes. Autant les phases liquides et vapeur que de combustion ont été caractérisées grâce à l’utilisation des plusieurs techniques optiques (extinction, Schlieren, chimiluminescence d’OH*) dans des conditions non réactives (Azote pur) et réactives (avec15% d'oxygène). Ces résultats expérimentaux ont non seulement permis d’étudier l’impact en oxygène moléculaire et de fournir une nouvelle base de données fiables, mais aussi d’affirmer la possibilité d’utiliser jusque 20% d’ABE en volume dans des moteurs à allumage par compression, grâce à ses caractéristiques de pulvérisation et de combustion similaires au carburant Diesel conventionnel
ผลกระทบของการใช้อะซิโตน-บิวทานอล-เอทานอลผสมดีเซลเป็นเชื้อเพลิงต่อเสถียรภาพการทำงานของเครื่องยนต์ดีเซลสูบเดียว The Effect of Acetone-Butanol-Ethanol Blended Diesel Fuel on the Engine Stability of a Single Cylinder Diesel Engine
No full textอะซิโตน-บิวทานอล-เอทานอล หรือ ABE เป็นเชื้อเพลิงทางเลือกหนึ่งที่กำลังได้รับความสนใจในการพิจารณาเป็นเชื้อเพลิงสำหรับเครื่องยนต์ดีเซลเนื่องจากมีคุณสมบัติที่ใกล้เคียงกับบิวทานอล อีกทั้งเมื่อผสม ABE กับน้ำมันดีเซลในสัดส่วนร้อยละ 20 โดยปริมาตร (ABE20) พบว่ามีคุณลักษณะของสเปรย์ทั้งในสถานะของเหลวและก๊าซที่ใกล้เคียงกับน้ำมันดีเซล แต่เมื่อพิจารณาตัวแปรด้านการเผาไหม้พบว่าค่าความล่าช้าในการจุดระเบิดของ ABE20 มีค่าสูงกว่าดีเซลอย่างมีนัยสำคัญ โดยทั่วไปแล้วการเพิ่มขึ้นของค่าความล่าช้าในการจุดระเบิดจะส่งผลกระทบต่อเสถียรภาพการทำงานของเครื่องยนต์ดีเซล ซึ่งสามารถวิเคราะห์ได้จากความแปรผันของวัฏจักรการทำงานของเครื่องยนต์ที่เพิ่มขึ้น ดังนั้น งานวิจัยนี้จึงมีวัตถุประสงค์เพื่อศึกษาผลกระทบการใช้ ABE20 เป็นเชื้อเพลิงต่อเสถียรภาพการทำงานของเครื่องยนต์ดีเซล โดยนำเครื่องยนต์ดีเซลสูบเดียวที่ไม่มีการดัดแปลงทดสอบบนไดนาโมมิเตอร์เพื่อควบคุมภาระการทำงานของเครื่องยนต์ที่มีค่าความดันยังผลเฉลี่ยบ่งชี้เท่ากับ 4 และ 8 บาร์ ที่ความเร็วรอบเครื่องยนต์ 1,400 รอบต่อนาที โดยวัดค่าความดันในกระบอกสูบเพื่อเปรียบเทียบความแปรผันของวัฏจักรการทำงานของเครื่องยนต์กับน้ำมันดีเซลล้วน รวมทั้งพิจารณาตัวแปรด้านสมรรถนะและการเผาไหม้เพื่อประกอบการวิเคราะห์ความมีเสถียรภาพของเครื่องยนต์ จากการวิเคราะห์คุณลักษณะการเผาไหม้และเสถียรภาพการทำงานของเครื่องยนต์พบว่า การมีค่าความล่าช้าในการจุดระเบิดและค่าความดันในกระบอกสูบสูงสุดของ ABE20 ที่มากกว่าดีเซลไม่ส่งผลกระทบต่อเสถียรภาพการทำงานของเครื่องยนต์ ซึ่งเห็นจากค่าสัมประสิทธิ์ความความแปรผันของวัฏจักรการทำงานของเครื่องยนต์ที่ไม่แตกต่างจากดีเซลอย่างมีนัยสำคัญและมีค่าที่น้อยกว่าค่าความแปรผันสูงสุดที่ยอมรับได้สำหรับเครื่องยนต์เผาไหม้ภายในAcetone-Butanol-Ethanol (ABE) has been interested as an alternative fuel for diesel engines due to its physical properties similar to butanol. Moreover, ABE-diesel blends in 20% by volume (ABE20) also performed the liquid and vapor spray characteristics close to diesel. However, the combustion characteristic of ABE20 was different from diesel by the longer ignition delay. Generally, the increasing of ignition delay affects on the engine stability of diesel engine operation, considered by the increasing of cyclic variation. Therefore, the objective of this work is to investigate the effect of the ABE20 on the engine stability of an unmodified single cylinder diesel engine. The engine was installed with an engine dynamometer in order to control the testing conditions at the engine loads 4 and 8 bar of IMEP and engine speed 1,400 rpm. The cylinder pressure was measured to compare the cyclic variation of engine operation with the reference diesel fuel. In addition, the engine performance and combustion parameters were also investigated to analysis the effect on engine stability. The experimental results show that the longer ignition delay and higher peak of cylinder pressure of ABE20 are unaffected to the engine stability, as presenting the value of coefficient of variation (COV) similar to diesel and lower than the acceptable limit for the internal combustion engines.Keywordsเครื่องยนต์ดีเซล; อะซิโตน-บิวทานอล-เอทานอล; เสถียรภาพของเครื่องยนต์; ความแปรผันของวัฏจักรDiesel Engines; Acetone-Butanol-Ethanol; Engine Stability; Cyclic Variatio
Genistein-mediated diet tends to increase oxidative stress in the vasculature of female ob/ob mice
No full textabstract: Morbid obesity is associated with cardiovascular and metabolic disorders. A major contributor to the pathogenesis of these diseases is impaired vasodilation resulting from elevated reactive oxygen species (ROS). This is because certain ROS such as superoxide are raised with obesity and scavenge the endogenous vasorelaxant nitric oxide, resulting in hypertension. The objective of this study was to measure the ability of genistein to quench superoxide in the vasculature of ob/ob mice, an animal model of obesity and type 2 diabetes. Genistein is an isoflavonic phytoestrogen naturally found in soy products. While genistein has documented antioxidant and anti-inflammatory properties, it is not known whether this protects the vasculature from oxidative stress. Genistein was hypothesized to reduce superoxide in arteries from female ob/ob mice. The superoxide indicator dihydroethidium (DHE) [2µL/mL HEPES buffer] was added to isolated aortae and mesenteric arteries from mice fed either a control (standard rodent chow containing 200-300 mg genistein/kg) or genistein-enriched (600mg genistein/kg rodent chow) diets for 4 weeks. Frozen tissues sections were collected onto glass microscope slides and examined using confocal microscopy. Contrary to the hypothesis, a diet containing twice the amount of genistein found in standard chow did not significantly reduce superoxide concentrations in aortae (p=0.287) or mesenteric arteries (p=0.352). Superoxide dismutase, an antioxidant enzyme that breaks down superoxide, was significantly upregulated in the genistein-enriched diet group (p=0.004), although this elevation did not promote the breakdown of superoxide. In addition, the inflammatory marker iNOS was not downregulated in the genistein-enriched diet group (p>0.05). The results indicate that high amounts of isoflavones, like genistein, may not exhibit the purported antioxidant effects in the vasculature of obese or diabetic subjects. Further studies examining arteries from ob/ob mice fed a genistein-free diet are needed to elucidate the true effects of genistein on oxidative stress
Sc-26196, a delta-6 desaturase inhibitor, normalizes glucose tolerance in ob/ob mice
Get PDF2012 Spring.Includes bibliographical references.The incidence of diabetes has reached epidemic levels worldwide, and while researchers know more about the phenomenon than ever, an effective treatment still remains elusive. Recently, chronic low-grade inflammation has been shown to play a key role in insulin resistance and diabetes. The purpose of this study was to demonstrate a role for the delta-6 desaturase (D6D) in diabetes, and furthermore to elucidate the potential mechanism by which inhibition of D6D by sc-26196 treatment could restore glucose tolerance in obese insulin resistant ob/ob mice. Treatment of 4-month-old male ob/ob mice with the selective D6D inhibitor sc-26196 (SC, 100 mg/kg/d for 4 weeks) improved response to an acute glucose challenge (1 mg/g BW i.p.), as indicated by lower peak (146% vs. 219% of fasting) and final (85% vs. 180% of fasting 2 hours-post bolus) blood glucose levels versus untreated ob/ob mice (p<0.01). Increased hepatic macrophage infiltration in addition to increased phosphorylation of JNK proteins and inhibitory IRS phosphorylation in untreated ob mice was attenuated by sc-26196 treatment, which suggests that D6D inhibition improves glucose tolerance by decreasing inflammation and restoring insulin signaling by way of the IRS/PI3K pathway. This study demonstrates the effectiveness of sc-26196 treatment for glucose intolerance in ob/ob mice and results warrant future studies for use of sc-26196 in the clinical treatment of insulin resistance and diabetes
Naravna in kulturna dediščina ob reki Dravi med Ptujem in Središčem ob Dravi na primeru zgodovinopisja ptujsko-ormoškega območja
Get PDFOn the example of the historiography of the Ptuj-Ormož area the author presents the knowledge about the natural and cultural heritage of the area at the Drava River between Ptuj and Središče ob Dravi which was gained as a consequence of the development of the places being located next to the river. The author is dealing with the relation of the society towards the natural and cultural heritage. She has focused on the presentation of natural parks with their specialties and on the results gained from protective and scientific archaeological researches that had been done because of planed environmental interventions. The extraordinary natural and archaeological richness between Ptuj and Središče ob Dravi - long ago this area gave shelter to people who had developed here their culture and enriched with it our everyday life - has been described in this paper by presenting the articles accessible in the literature from the end of the 20th and the beginning of the 21st century. Because of the extensiveness of the topic the author has limited herself to the survey of results about the natural and cultural heritage being presented by experts from the Ptuj-Ormož area.Na primeru zgodovinopisja ptujsko-ormoškega območja avtorica v prispevku predstavlja spoznanja o naravni in kulturni dediščini ob reki Dravi med Ptujem in Središčem ob Dravi, ki so nastala kot posledica razvoja krajev ob njej. Obravnava odnos družbe do naravne in kulturne dediščine. Osredotočila se je na prikaz naravnih parkov z njihovimi posebnostmi in na izsledke, pridobljene iz zaščitnih in znanstvenih arheoloških raziskovanj, opravljenih zaradi načrtovanih posegov v okolje. Izredno naravno in arheološko bogastvo med Ptujem in Središčem ob Dravi - to območje je že davno dajalo zavetje ljudem, ki so tu razvijali kulturo in z njo bogatili naš vsakdan - je v prispevku navedeno s predstavitvijo člankov v dostopni literaturi s konca 20. in začetka 21. stoletja. Zaradi obsežnosti teme se je avtorica omejila na prikaz izsledkov o naravni in arheološki dediščini, ki so jo predstavili strokovnjaki s ptujsko-ormoškega območja
OB-EIAD175 - Copper plates from Tummalagudem (set II), reign of Vikramendravarman II, year 11
No full textCopper plates from Tummalagudem (set II), reign of Vikramendravarman II, year 1
Impact of nitric oxide on n-heptane and n-dodecane autoignition in a new high-pressure and high-temperature chamber
No full textInternational audienc
Štrekljeva zbirka ljudskih pesmi ob prelomu stoletja
Get PDFThe author presents the most significant work of the Slovene folklorist and Slavist Karl Štrekelj, the book Slovenske narodni pesni 1-4 (1895-1923). He also discloses historical and social background which influenced the publication of teh collection. Štrekelj's significant views, particularly hist stand towards the folk culture, are introduced, and his work appraised.The author revises some earlier evaluations of Štrekelj's opus, made by Štrekelj's contemporaries and followers. By pointing to the both deficiencies and still valid aspects of Štrekelj's work, the author qualifies his contribution as exceptional for Slovenian folkloristics. He emphaisises however, the necessity of historical approach since by using contemporary criteria Štrekelj's work would be misprized.Avtor v svojem delu predstavlja najpomembnejše delo slovenskega slavista in folklorista Karla Štreklja, knjigo Slovenske narodne pesmi 1-4. Ob zbirki razgrinja zgodovinsko in družbeno ozadje, ki je vplivalo na zasnovo in izdajo zbirke, hkrati pa avtor predstavlja Štrekljev znanstveni nazor in njegov pogled na ljudsko kulturo in oceni Štrekljevo delo. Avtor revidira nekatere ocene Štrekljevih sodobnikov in nadaljevalcev njegovega dela. Ob opozarjanju na pomanjkljivosti in prispevek dobre srani Štrekljevega dela pa prikaže Štrekljev izjemni slovenskii folkloristiki, hkrati pa poudarja nujnost zgodovinskega pogleda, saj bi le z današnjimi merili krivično ovrednotili Štrekljevo ime
Suppressing hyperinsulinemia prevents obesity but causes rapid onset of diabetes in leptin-deficient Lepob/ob mice
No full textObjective: Hyperinsulinemia is commonly associated with obesity. Mice deficient in the adipose-derived hormone leptin (Lepob/ob) develop hyperinsulinemia prior to onset of obesity and glucose intolerance. Whether the excess of circulating insulin is a major contributor to obesity and impaired glucose homeostasis in Lepob/ob mice is unclear. It has been reported previously that diet-induced obesity in mice can be prevented by reducing insulin gene dosage. In the present study, we examined the effects of genetic insulin reduction in Lepob/ob mice on circulating insulin, body composition, and glucose homeostasis. Methods: Leptin expressing (Lepwt/wt) mice lacking 3 insulin alleles were crossed with Lepob/ob mice to generate Lepob/ob and Lepwt/wt littermates lacking 1 (Ins1+/+;Ins2+/−), 2 (Ins1+/+;Ins2−/−) or 3 (Ins1+/−;Ins2−/−) insulin alleles. Animals were assessed for body weight gain, body composition, glucose homeostasis, and islet morphology. Results: We found that in young Lepob/ob mice, loss of 2 or 3 insulin alleles reduced plasma insulin levels by 75–95% and attenuated body weight gain by 50–90% compared to Ins1+/+;Ins2+/−;Lepob/ob mice. This corresponded with ∼30% and ∼50% reduced total body fat in Ins1+/+;Ins2−/−;Lepob/ob and Ins1+/−;Ins2−/−;Lepob/ob mice, respectively. Loss of 2 or 3 insulin alleles in young Lepob/ob mice resulted in onset of fasting hyperglycemia by 4 weeks of age, exacerbated glucose intolerance, and abnormal islet morphology. In contrast, loss of 1,2 or 3 insulin alleles in Lepwt/wt mice did not significantly alter plasma insulin levels, body weight, fat mass, fasting glycemia, or glucose tolerance. Conclusion: Taken together, our findings indicate that hyperinsulinemia is required for excess adiposity in Lepob/ob mice and sufficient insulin production is necessary to maintain euglycemia in the absence of leptin. Author Video: Author Video Watch what authors say about their articles Keywords: Hyperinsulinemia, Lepob/ob, Obesity, Hyperglycemi
Adaptive Evolution of Leptin in Heterothermic Bats
No full textPMCID: PMC3217946This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
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