Supercritical Carbon dioxide Treatment of the Microalgae Nannochloropsis oculata

The aim of this work was to evaluate the potential of supercritical carbon dioxide (CO2) to extract Fatty Acid Methyl Esters (FAME) from the microalgae Nannochloropsis oculata (N. oculata) at low temperatures (37 and 55 oC) and pressures (5.9 and 7.6 megapascals (MPa)). A qualitative gas chromatography (GC) analysis showed that the individual FAMEs extracted varied depending on the co-solvent (methanol or hexane) used with supercritical CO2. Using hexane, FAME compounds produced were similar to those extracted with soxhlet extraction alone while longer chain FAME were produced when methanol was the co-solvent. The effects of pressure and temperature variations were shown to be of statistical significance. The chromatograms produced in this work demonstrate that altering one of these parameters (co-solvent, temperature, pressure) can produce different compounds owing to the tunability of the technique

Integrating anaerobic digestion and slow pyrolysis improves the product portfolio of a cocoa waste biorefinery

The integration of conversion processes with anaerobic digestion is key to increase value from agricultural waste, like cocoa pod husks, generated in developing countries. The production of one metric ton of cocoa beans generates some 15 metric tonnes of organic waste that is today underutilized. This waste can be converted into added value products by anaerobic digestion, converting part of the cocoa pods to biogas while releasing nutrients, and pyrolysis. Here, we compared different scenarios for anaerobic digestion/slow pyrolysis integration in terms of product portfolio (i.e., biogas, pyrolysis liquids, biochar and pyrolysis gases), energy balance and potential for chemicals production. Slow pyrolysis was performed at 350 degrees C and 500 degrees C on raw cocoa pod husks, as well as on digestates obtained from mono-digestion of cocoa pod husks and co-digestion with cow manure. Anaerobic digestion resulted in 20 to 25 wt% of biogas for mono and co-digestion, respectively. Direct pyrolysis of cocoa pod husks mainly resulted in biochar with a maximum yield of 48 wt%. Anaerobic digestion induced compositional changes in the resulting biochar, pyrolysis liquids and evolved gases after pyrolysis. Pyrolysis of mono-digestatee.g., resulted in a more energy-dense organic phase, rich in valuable phenolics while poorer in light oxygenates that hold a modest value. Our comparison shows that co-digestion/slow pyrolysis at 500 degrees C and mono-digestion/slow pyrolysis at 350 degrees C both present high-potential biorefinery schemes. They can be self-sustaining in terms of energy, while resulting in high quality biochar for nutrient recycling and/or energy recovery, and/or phenolics-rich pyrolysis liquids for further upgrading into biorefinery intermediates

Proje Temelli Eğitimin Kümeleme ve Sınıflama Algoritmaları İle Değerlendirilmesi

Günümüzde bilgisayar teknolojileri her alanda etkin rol oynamaktadır. Teknolojinin gelişmesiyle her ortamda veriler daha kolay tutulmakta ve bu verileri bilgisayar programları aracılığıyla analiz edecek uzman kişilere olan talep de bu duruma müteakip dünya genelinde artmaktadır. Veri analizi konusunda yeterli düzeyde teorik bilgi edinen Ekonometri mezunlarının Veri Analisti olarak kariyerlerini devam ettirmelerindeki en büyük engel ise bilgisayar teknolojilerine olan uzaklıklarıdır. Bu nedenle Ekonometri Bölümü öğrencilerinin bilgisayar kullanım düzeylerini arttıracak eğitimsel yaklaşımlar gerekmektedir. Bilgisayarda yetkinliğin uzun süreli ve ders saatleri dışında da yapılacak olan çalışmalarla kazanılabilmesi nedeniyle proje tabanlı ders yaklaşımları bu durumlarda kullanılabilmektedir. Projeler ile öğrenciler ekip çalışması, araştırma yeteneği, uygulayarak öğrenme ve kendi başlarına öğrenme gibi birçok alanda kendilerini geliştirme şansına sahip olmaktadırlar. Çalışmada bilgisayar ortamında paket programlar kullanılarak proje çalışması yapılan derslerin lisans öğrencilerinin eğitimlerine ne ölçüde etki ettiği incelenmiştir. Bu kapsamda, Likert ve Boolean tipi değişkenlerden meydana gelen bir anket hazırlanmış ve Dokuz Eylül Üniversitesi Ekonometri Bölümü öğrencisi olan 184 kişiye uygulanmıştır. Anket verileri veri madenciliği teknikleri olan iki aşamalı kümeleme ve Ki Kare ölçütlü sınıflama yöntemleriyle değerlendirilerek önemli çıkarımlar sağlanmıştır

Regional intravenous anesthesia in knee arthroscopy

OBJECTIVE: The goal of the study was to investigate the regional intravenous anesthesia procedure in knee arthroscopy and to evaluate the effects of adding ketamine over the anesthesia block charactery and tourniquet pain. MATERIAL/METHOD: Forty American Society of Anesthesiologists (ASA) II patients who received knee arthroscopy were enrolled. After monitoring, a peripheral IV line was inserted.The venous blood in the lower extremity was evacuated with a bandage, and the proximal cuff of the double-cuff tourniquet was inflated. The patients were randomly split into two groups. While Group P received 80 ml 0.5% prilocaine, Group PK received 0.15 mg/kg ketamine (80 ml in total) via the dorsum of the foot. We recorded onset time of the sensory block, end time of the sensory block, presence of the motor block, the time when the patient verbally reported tourniquet pain and surgical pain, duration of tourniquet tolerance, fentanyl consumption during the operation, time to first analgesic requirement, methemoglobin values at 60 minutes, operative conditions, 24-hour analgesic consumption, discharge time, and hemodynamic parameters. RESULTS: The body mass index (BMI) of the patients who required general anesthesia was significantly higher than the BMI of other patients. The onset time of the sensory block was shorter for those in Group PK, but the time to first analgesic requirement was longer. CONCLUSION: Regional intravenous anesthesia using the doses and volumes commonly used in knee arthroscopy may be an inadequate block among patients with high BMI values. Moreover, the addition of ketamine to the local anesthetic solution may produce a partial solution by shortening the onset of sensory block and prolonging the time until the first analgesic is required

Regional intravenous anesthesia in knee arthroscopy

OBJECTIVE: The goal of the study was to investigate the regional intravenous anesthesia procedure in knee arthroscopy and to evaluate the effects of adding ketamine over the anesthesia block charactery and tourniquet pain. MATERIAL/METHOD: Forty American Society of Anesthesiologists (ASA) II patients who received knee arthroscopy were enrolled. After monitoring, a peripheral IV line was inserted.The venous blood in the lower extremity was evacuated with a bandage, and the proximal cuff of the double-cuff tourniquet was inflated. The patients were randomly split into two groups. While Group P received 80 ml 0.5% prilocaine, Group PK received 0.15 mg/kg ketamine (80 ml in total) via the dorsum of the foot. We recorded onset time of the sensory block, end time of the sensory block, presence of the motor block, the time when the patient verbally reported tourniquet pain and surgical pain, duration of tourniquet tolerance, fentanyl consumption during the operation, time to first analgesic requirement, methemoglobin values at 60 minutes, operative conditions, 24-hour analgesic consumption, discharge time, and hemodynamic parameters. RESULTS: The body mass index (BMI) of the patients who required general anesthesia was significantly higher than the BMI of other patients. The onset time of the sensory block was shorter for those in Group PK, but the time to first analgesic requirement was longer. CONCLUSION: Regional intravenous anesthesia using the doses and volumes commonly used in knee arthroscopy may be an inadequate block among patients with high BMI values. Moreover, the addition of ketamine to the local anesthetic solution may produce a partial solution by shortening the onset of sensory block and prolonging the time until the first analgesic is required

Electrochemical upgrading of bio-oil: A proof-of-principle investigation

Fast pyrolysis is an advanced thermochemical conversion technology developed to produce bio-oil from biomass. With lignocellulosic biomass, high product yields (65-75 wt.%) can be attained. Yet, certain unfavorable characteristics of bio-oil impede its utilization prospects. High water content, high oxygen content, together with instability and acidity are the recognized adverse features of bio-oil. Tackling these issues is possible by reducing the oxygen content and/or steering the oxygen functionality of bio-oils. Electrochemical hydrogenation (ECH) is a recently proposed approach targeting the reduction of the reactive compounds in bio-oil (aldehydes, ketones etc.) to their corresponding alcohols, diols [1]. In this attractive approach, the water present in bio-oil acts as the hydrogen source for reduction reactions. Production of alcohols/diols leads to an upgraded/stabilized bio-oil product. Performing the upgrading at ambient temperature, pressure and providing a means to store intermittently available renewable energy (e.g. solar, wind) are clear advantages of the ECH process. In this work, we have investigated electrochemical upgrading of bio-oil using water soluble bio-oil (WSBO) as feed. The ECH experiments, carried out in an electrochemical reactor at a current density of 44 mA cm-2, focused on comparison of several cathode materials. Separated by a cation exchange membrane, cathode and anode chambers of the reactor were filled with WSBO (ca. 20 wt.% bio-oil in aqueous solution) and 1M H2SO4, respectively. The tested cathode materials included Ti, Ru-coated Ti (Ru), Pt-coated Ti (Pt), stainless steel (SS) and CuZn (brass) electrodes. All electrodes converted the carbonyl groups present in bio-oil to a certain extent following the order CuZn\u3e\u3eSS\u3eTi\u3ePt\u3eRu. The trend is explained in close relation with the hydrogen evolution reaction, the preferred pathway especially with Pt and Ru electrodes. Despite the high conversions achieved for some compounds, the selectivity towards desired alcohols and diols was not very high (e.g. 15 – 49% ethylene glycol selectivity for glycolaldehyde conversion) for the electrodes tested in this study. Low Faradaic efficiencies obtained are considered as another challenge keeping the conversion costs high. Nevertheless, electrochemical hydrogenation appears to be a promising technology to upgrade/stabilize bio-oil that deserves further investigation. Next to the experimental results obtained, possible future improvements in catalytic cathode selection and processing options will be discussed as well. References [1] Z. Li, S. Kelkar, L. Raycraft, M. Garedew, J.E. Jackson, D.J. Miller, C.M. Saffron, Green Chem., 2014, 16, 844

A Comparison of Epidural Anesthesia and Lumbar Plexus-Sciatic Nerve Blocks for Knee Surgery

OBJECTIVES: The efficacy of combined lumbar plexus-sciatic nerve blocks was compared to epidural anesthesia in patients undergoing total knee surgery. PATIENTS AND METHODS: The study included 80 American Society of Anesthesiologists (ASA) Physical Status I-III patients (age range 18 to 65) undergoing knee surgery. The patients were randomly divided into one of two groups. Epidural anesthesia was performed in the epidural anesthesia (EA) group (n=40), and the lumbar plexus and sciatic nerves were blockedin the lumbar plexus-sciatic nerve blocks (LPSB) group (n=40). For each patient, onset of sensory and motor block, degree of motor block, sign of sensory block in the contralateral lower limb for the lumbar plexus-sciatic nerve blocks group, success in providing adequate anesthesia, hemodynamic changes, time of first analgesic request, and patient and surgeon satisfaction with the anesthetic technique were recorded. RESULTS: One patient in the epidural anesthesia group and three patients in the lumbar plexus-sciatic nerve blocks group required general anesthesia due to failed block. There were no significant differences between the two groups regarding the success of providing adequate anesthesia. Eight patients in the lumbar plexus-sciatic nerve blocks group developed contralateral spread. The onset of sensory-motor block and the time of the first analgesic request were significantly later in the lumbar plexus-sciatic nerve blocks group than in the epidural anesthesia group. Although there were no significant differences regarding patient satisfaction with the anesthetic technique between the two groups, surgeon satisfaction was significantly higher in the lumbar plexus-sciatic nerve blocks group than in the epidural anesthesia group. CONCLUSION: The lumbar plexus -sciatic nerve blocks provide effective unilateral anesthesia and may offer a beneficial alternative to epidural anesthesia in patients undergoing total knee surgery