Algae biofuel: Current status and future applications

An algal feedstock or biomass may contain a very high oil fraction, and thus could be used for the production of advanced biofuels via different conversion processes. Its major advantage apart from its large oil fraction is the ability to convert almost all the energy from the feedstock into different varieties of useful products. In the research to displace fossil fuels, algae feedstock has emerged as a suitable candidate not only because of its renewable and sustainable features but also for its economic credibility based on the potential to match up with the global demand for transportation fuels. Cultivating this feedstock is very easy and could be developed with little or even no supervision, with the aid of wastewater not suitable for human consumption while absorbing CO2 from the atmosphere. The overall potential for algae applications generally shows that this feedstock is still an untapped resource, and it could be of huge commercial benefits to the global economy at large because algae exist in millions compared to terrestrial plants. Algae applications are evident for everyday consumption via foods products, non-foods products, fuel, and energy. Biofuels derived from algae have no impact on the environment and the food supply unlike biofuels produced from crops. However, any cultivation method employed could control the operating cost and the technicalities involved, which will also influence the production rate and strain. The scope of this paper is to review the current status of algae as a potential feedstock with diverse benefit for the resolution of the global energy demand, and environmental pollution control of GHG

Modelling of Self-Ignition in Spark-Ignition Engine Using Reduced Chemical Kinetics for Gasoline Surrogates

A numerical and experimental investigation in to the role of gasoline surrogates and their reduced chemical kinetic mechanisms in spark ignition (SI) engine knocking has been carried out. In order to predict autoignition of gasoline in a spark ignition engine three reduced chemical kinetic mechanisms have been coupled with quasi-dimensional thermodynamic modelling approach. The modelling was supported by measurements of the knocking tendencies of three fuels of very different compositions yet an equivalent Research Octane Number (RON) of 90 (ULG90, PRF90 and 71.5% by volume toluene blended with n-heptane) as well as iso-octane. The experimental knock onsets provided a benchmark for the chemical kinetic predictions of autoignition and also highlighted the limitations of characterisation of the knock resistance of a gasoline in terms of the Research and Motoring octane numbers and the role of these parameters in surrogate formulation. Two approaches used to optimise the surrogate composition have been discussed and possible surrogates for ULG90 have been formulated and numerically studied. A discussion has also been made on the various surrogates from the literature which have been tested in shock tube and rapid compression machines for their autoignition times and are a source of chemical kinetic mechanism validation. The differences in the knock onsets of the tested fuels have been explained by modelling their reactivity using semi-detailed chemical kinetics. Through this work, the weaknesses and challenges of autoignition modelling in SI engines through gasoline surrogate chemical kinetics have been highlighted. Adequacy of a surrogate in simulating the autoignition behaviour of gasoline has also been investigated as it is more important for the surrogate to have the same reactivity as the gasoline at all engine relevant p−T conditions than having the same RON and Motored Octane Number (MON)

Diffusion layer thickness in turbulent flow

Average thickness of diffusive layers in a turbulent flow is described usingan idea of Lagrangian meso-scale element convected by mean flow and largescale turbulence. This idea enables a formulation of a simple model for thediffusive layer thickness assuming that its evolution is determined by thediffusive growth and two components, compressive normal and tangential, ofthe turbulent strain rate tensor. Analysis of the possible effects of the foldingaction of the turbulence leads to the conclusion that the folding becomessignificant only at the scales far superior to the considered dimensions of themeso-scale elements, thus it may be neglected in the present formulation. Theevolution equation for the meso-scale element thickness is derived and putto test against experiments conducted in plane and round jets. The modelproved capable of producing, using the same values of two model constants,values of the diffusive layer thickness in good qualitative agreement with themeasurements.While the present numerical simulations of the turbulent jets are madeusing very simple, perhaps simplistic, flow and turbulence description, theynonetheless allow a fairly accurate estimation of turbulence microscales atdifferent locations in a jet. It turns out that neither Kolmogorov nor Taylorscale provides a good universal reference scale for the diffusive layer thicknessand it is local turbulence conditions and history of the meso-scale elementdetermining the latter

САМООСВІТА ЯК УМОВА СОЦІАЛЬНОЇ НЕЗАЛЕЖНОСТІ І САМОСТІЙНОСТІ ОСОБИСТОСТІ

Досліджено як в сучасній культурній ситуації самоосвіта уможливлює соціокультурну незалежність і самостійність особистості. Відмічено, що сучасна система освіти орієнтована на активність особистості, самостійність у виборі тематики і часу засвоєння інформації. Показано як демократичний тип організації самоосвіти, позбавляє особистість залежності, дозволяє вийти на новий рівень духовної свободи і реалізувати свій творчий потенціал

Experimental observations on the influence of hydrogen atoms diffusion on laminar and turbulent premixed burning velocities

Measurements of the laminar and turbulent burning velocity of premixed hydrogen–air, n-hexane–air and n-octane–air flames were made and compared to corresponding measurements of deuterium–air, n-hexane-d14–air and n-octane-d18–air flames performed at identical initial conditions. Experiments were conducted in a constant volume, optically accessed vessel, at elevated initial pressure and temperature of 0.5 MPa and 360 K, for a range of equivalence ratios. Burn rate data was determined via schlieren imaging of flames. It was found that the isotope effect accounted for an average reduction of 20% in the laminar burn rate of alkanes. Similarly, deuterium was measured to burn around 30% slower than hydrogen at the range of equivalence ratios explored. The isotope effect on burn rate was significantly reduced under turbulence. The difference between the turbulent burn rates of the deuterated alkanes and their normal alkane counterparts were measured to be approximately 10%. The difference between the turbulent burn rates of deuterium and hydrogen was even smaller. Nonetheless, the laminar burn rate ranking was maintained under turbulence for all fuels and conditions explored, thus suggesting a degree of influence of radical transport and chemistry under turbulent burning

Аналіз сучасних методів діагностики у постраждалих з нестабільними пошкодженнями таза і тазових органів при політравмі в гострому періоді травматичної хвороби

The aim of research was improvement of the diagnostic program in patients with unstable injuries of pelvis and pelvic organs at polytrauma based on the trauma severity estimation for the choice of the optimal surgical therapeutic approach in acute traumatic disease period.Materials and methods. The analysis of the diagnostic programs in acute traumatic disease period in 406 patients with unstable injuries of pelvis at polytrauma, who were taken to the Kyiv city clinical emergency hospital, was carried out. 249 (61.3 %) of them died, and 157 (38.7 %) of them survived. Pelvic organs were injured in 98 (24.1 %) cases (in 47 (29.9 %) cases – in survivors, and in 51 (20.5 %) cases – in dead patients). According to the Pape HC., Krettek C. (2003) scale, all patients were divided into three groups: boundary condition (minor injury, ISS 17–25 points), unstable condition (severe injury, ISS 26–40 points), critical condition (very severe trauma, ISS more, than 40 points). We used general clinical, laboratory, ray (X-ray research, retrograde contrast uretra cystography, spiral CT, ultrasonography in the abridged version), and instrumental methods.Results. In the acute trauma period in patients with unstable injuries of pelvis at polytrauma depending on the severity of trauma, ray diagnostic methods were carried out in the following order: plain radiography of pelvis, multi projection oblique, spiral CT (at stable hemodynamic). In unstable and critical patients (ISS 26–40, more, than 40 points), plain radiography of pelvis is complemented by ultrasonography in the abridged version, which together with the data of clinical examination confirms pelvic ring instability in 67.9 % of cases. The scheme of diagnostic studies in patients with unstable injuries of pelvis at polytrauma considering the severity of trauma allowed reducing the time for patients in unstable condition examination to 13.7±3.5 minutes, for patients in critical condition – to 16.7±4.1 minutes. Informational content of the measures with a minimum amount was 52.3 %, with shorten amount – 75.4 %, with full amount – 92.1 %.The obtained results made it possible to develop the scheme of ray diagnostic of pelvic ring, as well as to reduce the time for detection of injuries of pelvic organs in patients in unstable and critical conditions, which determined the surgical therapeutic approach in acute traumatic disease periodМетою дослідження було удосконалення діагностичної програми у постраждалих з нестабільними пошкодженнями таза і тазових органів при політравмі на основі оцінки тяжкості травми з метою вибору оптимальної хірургічної тактики лікування в гострому періоді травматичної хвороби. Одержані результати дозволили розробити схему променевої діагностики нестабільного тазового кільця, а також скоротити терміни виявлення пошкоджень тазових органів у пацієнтів при нестабільному і критичному стана

Удосконалена система хірургічного лікування постраждалих з пошкодженнями таза та тазових органів при політравмі

Мета. Оцінити ефективність удосконаленої системи хірургічного лікування постраждалих з пошкодженнями таза та тазових органів при політравмі. Матеріали і методи. В основу дослідження покладено клінічні спостереження 406 постраждалих з нестабільними пошкодженнями таза (НПТ) при політравмі (оцінка тяжкості за шкалою ISS 17 балів і вище).  НПТ у 98 (24,1%) постраждалих з політравмою були поєднані з пошкодженнями тазових органів. Сформовано дві клінічні групи: основну – 137 (33,7%) постраждалих, із них у 37 (27,0%) НПТ були поєднані з пошкодженнями тазових органів, і контрольну – 269 (66,3%) постраждалих, із них у 61 (22,7%) постраждалого НПТ були поєднані з пошкодженнями тазових органів. У постраждалих основної групи застосована диференційована хірургічна тактика лікування, яка базувалась на оцінці тяжкості травми, прогнозі перебігу травматичної хвороби (ТХ) у залежності від її періодів, а також запропонованих сучасних методах діагностики і лікування пошкоджень таза й інших анатомічних ділянок (АД). Для лікування пацієнтів контрольної групи застосовували хірургічну тактику згідно з тимчасовими галузевими уніфікованими стандартами медичних технологій діагностично-лікувального процесу стаціонарної допомоги дорослому населенню в лікувально-профілактичних закладах України, затвердженими наказом МОЗ України №226 від 27 липня 1998 р. Результати. При травмі сечового міхура у 47 (83,9%) постраждалих зашили розрив стінки міхура з епіцистостомією і катетеризацією міхура катетером Фолея. При травмі уретри епіцистостомію поєднували з шинуванням уретри катетером у 27 (81,8%) хворих. У 3 пацієнтів основної групи використали первинний шов уретри в гострому періоді ТХ. У всіх пацієнтів з пошкодженнями прямої кишки накладали дводульну сигмостому. Операції на внутрішніх статевих органах виконані 3 (3,2%) постраждалим. Усього на тазових органах у гострому періоді ТХ виконано 94 оперативних втручання різної складності. Висновки. При політравмі переломи кісток таза були поєднані з травмою тазових органів у 24,1% постраждалих. Поєднане пошкодження тазових органів (за винятком пошкоджень прямої кишки) не є протипоказанням до виконання внутрішнього або комбінованого металоостеосинтезу нестабільного тазового кільця у постраждалих з політравмою в ранньому та пізньому періодах ТХ

Turbulent burning rates of gasoline components, Part 2-Effect of carbon number

Experimental measurements of turbulent and laminar burning velocities have been made for premixed hydrocarbon–air flames of straight chain molecules of increasing carbon number (from n-pentane to n-octane). Measurements were performed at 0.5 MPa, 360 K and rms turbulent velocities of 2 and 6 m/s, for a range of equivalence ratios. The laminar burning velocities were used to interpret the turbulent data, but were also found to be broadly in line with those of previous workers. At lean conditions the turbulent burning velocity was measured to be similar between the four alkanes studied. However, at rich conditions there were notable differences between the turbulent burn rates of the fuels. The equivalence ratio of the mixtures at which the maximum burning velocities occurred in the turbulent flames was richer than that under laminar conditions. The equivalence ratio of the peak turbulent burning velocity was found to be a function of the carbon number of the fuel and the turbulent intensity and became gradually fuel rich with increases in each of these values