An Alternative Approach to the Fracture Toughness of Dual Phase Steels

In this study, the effects of ferrite morphology and of ferrite volume fraction on the mechanical properties and the fracture toughness values ( ) KIc of dual phase steels were investigated. The fracture toughness values were determined using an approach that was different from the standard one. A homogenization heat treatment was applied to the steels. Two different starting microstructures were then obtained by either the full annealing of or the quenching of the steels from austenite before applying intercritical annealing to the steels in the austenite region. After this process, dual phase steels with two types of morphology, coarse and fine, were obtained with 40, 20, and 10% ferrite volume fractions, depending on the starting microstructure. Tempered specimens with 10% ferrite exhibited improved fracture toughness values compared with those of the other steels.Исследуется влияние морфологии структуры феррита и его объемного содержания на механические свойства и вязкость разрушения двухфазных сталей. Для определения значений вязкости разрушения использовали не стандартный, а альтернативный подход. Стали подвергали гомогенизирующей термообработке. Путем полного отжига или закалки сталей из аустенитного состояния до применения докритического отжига в аустенитной области получены две различные исходные микроструктуры. Получены двухфазные стали с двумя типами морфологии (крупно- и мелкозернистая) с 40-, 20- и 10%-ным объемным содержанием феррита в зависимости от исходной микроструктуры. Отпущенные образцы с 10%-ным объемным содержанием феррита имели более высокие значения вязкости разрушения по сравнению с таковыми других образцов из этих сталейДосліджується вплив морфології структури фериту та його об’ємного вмісту на механічні властивості і в’язкість руйнування двофазних сталей. Для визначення значень в’язкості руйнування використовували не стандартний, а альтернативний підхід. Сталі піддавали гомогенізуючій термообробці. Шляхом повного відпалу або загартування сталей з аустенітного стану до використання докритичного відпалу в аустенітній області отримано дві різні початкові мікроструктури. Отримано двофазні сталі з двома типами морфології (великоі дрібнозеренна) з 40-, 20- і 10%-ним об’ємним вмістом фериту в залежності від початкової мікроструктури. Відпущені зразки з 10%-ним об’ємним вмістом фериту мали більш високі значення в’язкості руйнування порівняно з такими інших зразків із цих сталей

Rumput Laut (Ulva lactuca) sebagai Pakan Substitusi Sapi Bali Sapihan di Musim Kemarau dengan Level Energi yang Berbeda

Penelitian dilakukan untuk mengetahui kualitas dan pengaruh rumput laut (Ulva lactuca) sebagai pakan substitusi untuk sapi Bali sapihan di musim kemarau dengan level energi yang berbeda. Penelitian dilakukan dua tahap yaitu perlakuan in vitro untuk mengetahui level ideal pemberian tepung U. lactuca dengan perlakuan RA = hay rumput alam; RAK = RA+konsentrat; RAKU5 =RAK+U. lactuca 5%; RAKU10= RAK+U. lactuca 10%; RAKU15= RAK+U. lactuca 15%; RAKU20= RAK+U. lactuca 20%. Tahap kedua menggunakan rancangan Bujur Sangkar Latin dengan perlakuan R1 = EM 7,3 MJ, R2 = EM 8 MJ dan R3 = EM 8,7 MJ. Hasil penelitian menunjukkan bahwa level ideal pemberian yang dapat digunakan adalah 15% dengan nilai kecernaan bahan kering dan bahan organik tertinggi yaitu 77,79 dan 78,56%.  Tahap kedua yaitu pemberian tepung U. lactuca sebanyak 15% dari total ransum dengan level energy yang berbeda untuk sembilan ekor sapi Bali sapihan dengan tujuan mengetahui tingkat konsumsi dan kecernaan dengan perlakuan EM R1= 7,3 MJ; R= 8 MJ; dan R3= 8,7 MJ. Hasil penelitian menunjukkan bahwa substitusi tepung U. lactuca sebanyak 15% tidak memberikan pengaruh negatif terhadap konsumsi dan kecernaan. Hasil sidik ragam menunjukkan ransum dengan energi 8 MJ memiliki konsumsi dan kecernaan yang sama dengan energi 8,7 MJ namun lebih tinggi dibandingkan dengan ransum  berenergi 7,3 MJ

High-speed >90% quantum-efficiency p–i–n photodiodes with a resonance wavelength adjustable in the 795–835 nm range

Cataloged from PDF version of article.We report GaAs/AlGaAs-based high-speed, high-efficiency, resonant cavity enhanced p–i–nphotodiodes. The devices were fabricated by using a microwave-compatible fabrication process. By using a postprocess recess etch, we tuned the resonance wavelength from 835 to 795 nm while keeping the peak efficiencies above 90%. The maximum quantum efficiency was 92% at a resonance wavelength of 823 nm. The photodiode had an experimental setup-limited temporal response of 12 ps. When the system response is deconvolved, the 3 dB bandwidth corresponds to 50 GHz, which is in good agreement with our theoretical calculations. © 1999 American Institute of Physic

Omega-3 Fatty Acid-Derived Resolvin D2 Regulates Human Placental Vascular Smooth Muscle and Extravillous Trophoblast Activities

Omega-3 fatty acids are important to pregnancy and neonatal development and health. One mechanism by which omega-3 fatty acids exert their protective effects is through serving as substrates for the generation of specialized pro-resolving lipid mediators (SPM) that potently limit and resolve inflammatory processes. We recently identified that SPM levels are increased in maternal blood at delivery as compared to umbilical cord blood, suggesting the placenta as a potential site of action for maternal SPM. To explore this hypothesis, we obtained human placental samples and stained for the SPM resolvin D2 (RvD2) receptor GPR18 via immunohistochemistry. In so doing, we identified GPR18 expression in placental vascular smooth muscle and extravillous trophoblasts of the placental tissues. Using in vitro culturing, we confirmed expression of GPR18 in these cell types and further identified that stimulation with RvD2 led to significantly altered responsiveness (cytoskeletal changes and pro-inflammatory cytokine production) to lipopolysaccharide inflammatory stimulation in human umbilical artery smooth muscle cells and placental trophoblasts. Taken together, these findings establish a role for SPM actions in human placental tissue

Something Smells Fishy: How Lipid Mediators Impact the Maternal–Fetal Interface and Neonatal Development

Normal pregnancy relies on inflammation for implantation, placentation, and parturition, but uncontrolled inflammation can lead to poor maternal and infant outcomes. Maternal diet is one modifiable factor that can impact inflammation. Omega-3 and -6 fatty acids obtained through the diet are metabolized into bioactive compounds that effect inflammation. Recent evidence has shown that the downstream products of omega-3 and -6 fatty acids may influence physiology during pregnancy. In this review, the current knowledge relating to omega-3 and omega-6 metabolites during pregnancy will be summarized

Omega-3 Fatty Acid-Derived Resolvin D2 Regulates Human Placental Vascular Smooth Muscle and Extravillous Trophoblast Activities

Omega-3 fatty acids are important to pregnancy and neonatal development and health. One mechanism by which omega-3 fatty acids exert their protective effects is through serving as substrates for the generation of specialized pro-resolving lipid mediators (SPM) that potently limit and resolve inflammatory processes. We recently identified that SPM levels are increased in maternal blood at delivery as compared to umbilical cord blood, suggesting the placenta as a potential site of action for maternal SPM. To explore this hypothesis, we obtained human placental samples and stained for the SPM resolvin D2 (RvD2) receptor GPR18 via immunohistochemistry. In so doing, we identified GPR18 expression in placental vascular smooth muscle and extravillous trophoblasts of the placental tissues. Using in vitro culturing, we confirmed expression of GPR18 in these cell types and further identified that stimulation with RvD2 led to significantly altered responsiveness (cytoskeletal changes and pro-inflammatory cytokine production) to lipopolysaccharide inflammatory stimulation in human umbilical artery smooth muscle cells and placental trophoblasts. Taken together, these findings establish a role for SPM actions in human placental tissue

Something Smells Fishy: How Lipid Mediators Impact the Maternal-Fetal Interface and Neonatal Development

Normal pregnancy relies on inflammation for implantation, placentation, and parturition, but uncontrolled inflammation can lead to poor maternal and infant outcomes. Maternal diet is one modifiable factor that can impact inflammation. Omega-3 and -6 fatty acids obtained through the diet are metabolized into bioactive compounds that effect inflammation. Recent evidence has shown that the downstream products of omega-3 and -6 fatty acids may influence physiology during pregnancy. In this review, the current knowledge relating to omega-3 and omega-6 metabolites during pregnancy will be summarized

Omega-6 and Omega-3 Fatty Acid-Derived Oxylipins from the Lipoxygenase Pathway in Maternal and Umbilical Cord Plasma at Delivery and Their Relationship with Infant Growth

Omega-3 and omega-6 fatty acids are important for neonatal development and health. One mechanism by which omega-3 and omega-6 fatty acids exert their effects is through their metabolism into oxylipins and specialized pro-resolving mediators. However, the influence of oxylipins on fetal growth is not well understood. Therefore, the objective of this study was to identify oxylipins present in maternal and umbilical cord plasma and investigate their relationship with infant growth. Liquid chromatography-tandem mass spectrometry was used to quantify oxylipin levels in plasma collected at the time of delivery. Spearman\u27s correlations highlighted significant correlations between metabolite levels and infant growth. They were then adjusted for maternal obesity (normal body mass index (BMI: ≤30 kg/m2) vs. obese BMI (\u3e30 kg/m2) and smoking status (never vs. current/former smoker) using linear regression modeling. A p-value \u3c 0.05 was considered statistically significant. Our study demonstrated a diverse panel of oxylipins from the lipoxygenase pathway present at the time of delivery. In addition, both omega-3 and omega-6 oxylipins demonstrated potential influences on the birth length and weight percentiles. The oxylipins present during pregnancy may influence fetal growth and development, suggesting potential metabolites to be used as biomarkers for infant outcomes