Effect of Fuel Type on Flame Ignition by Transient Plasma Discharges

Rise and delay times of mixtures of methane, propane, n-butane, iso-butane and iso-octane mixed with air ignited by transient plasma discharge were investigated and compared with spark discharge ignition. Multi-ignition site effect and high electron energy are suggested to contribute to shortening of rise and delay times

Traffic placement policies for a multi-band network

Recently protocols were introduced that enable the integration of synchronous traffic (voice or video) and asynchronous traffic (data) and extend the size of local area networks without loss in speed or capacity. One of these is DRAMA, a multiband protocol based on broadband technology. It provides dynamic allocation of bandwidth among clusters of nodes in the total network. A number of traffic placement policies for such networks are proposed and evaluated. Metrics used for performance evaluation include average network access delay, degree of fairness of access among the nodes, and network throughput. The feasibility of the DRAMA protocol is established through simulation studies. DRAMA provides effective integration of synchronous and asychronous traffic due to its ability to separate traffic types. Under the suggested traffic placement policies, the DRAMA protocol is shown to handle diverse loads, mixes of traffic types, and numbers of nodes, as well as modifications to the network structure and momentary traffic overloads

Extremely high data-rate, reliable network systems research

Significant progress was made over the year in the four focus areas of this research group: gigabit protocols, extensions of metropolitan protocols, parallel protocols, and distributed simulations. Two activities, a network management tool and the Carrier Sensed Multiple Access Collision Detection (CSMA/CD) protocol, have developed to the point that a patent is being applied for in the next year; a tool set for distributed simulation using the language SIMSCRIPT also has commercial potential and is to be further refined. The year's results for each of these areas are summarized and next year's activities are described

High-Speed Flow and Fuel Imaging Study of Available Spark Energy in a Spray-Guided Direct-Injection Engine and Implications on Misfires

The spark energy transferred under the highly stratified conditions during late injection in a spray-guided spark-ignition direct-injection (SG-SIDI) engine is not well characterized. The impact of high pressures, temperatures, velocities, and variations in local fuel concentration along with temporal and/or spatial variations on spark performance must be better characterized. Previous spark ignition studies have not addressed the full range of conditions that are present in SG-SIDI engines. Therefore, high-speed particle image velocimetry (PIV) experiments are conducted to characterize the spark energy dependence for a wide range of well-defined homogeneous fuel–air equivalence ratios (W50–2.9) and average air velocities (0–8m/s) in an optical SG-SIDI engine. Amoderate dependence of spark energy on equivalence ratio is shown to exist with average values of spark energy increasing by 21 per cent for the equivalence ratio range of W50–2.3. Air injection into the motored engine is used to prepare well-defined flow conditions without the complications of fuel concentration gradients that are present during fuel injection. This allows the study of the effects of velocity, shear strain rate, and vorticity on spark energy. The spark energy increases with velocity at the spark plug. This observation is consistent with findings reported in the literature for low-pressure conditions. A linear increase is shown between shear strain rate and spark energy, while vorticity and spark energy are only weakly correlated. Simultaneous high-speed PIV, planar laser-induced fluorescence, and spark-discharge electrical measurements are also performed in the optical SG-SIDI engine to measure flow properties and fuel concentrations under late injection. Operating parameters are chosen to be near peak indicated mean effective pressure performance, but they occasionally provide a random misfired or partial burned cycle. Misfired cycles occur under stoichiometric-to-lean mixtures and low velocities near the spark plug. The lower spark energies observed under these conditions are in agreement with the observationsmade under well-controlled mixture and flow conditions reported in this study. All mixture conditions found in misfiring and partially burning cycles are within the ignitability range and fall within the general population of all, predominantly well-burning, cycles. There is no predominant impact of shear strain rate and vorticity under late injection operation on misfires and partial burns.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86771/1/Sick7.pd

Effect of obesity on knee joint biomechanics during gait in young adults

This article is MacLean, K. F. E., Callaghan, J. P., & Maly, M. R. (2016). Effect of obesity on knee joint biomechanics during gait in young adults. Cogent Medicine, 3(1). https://doi.org/10.1080/2331205X.2016.1173778While there are many comorbidities associated with obesity, one of the more poorly understood is knee osteoarthritis through obesity. The purpose of this study was to compare the kinematics and kinetics of gait and cumulative knee adductor load, which represents the sum of repetitive exposures to medial knee loading during daily activity, between young obese adults with young, healthy-weight adults. Eight obese and eight healthy-weight young adults participated. Data from a three-dimensional motion capture system and a synchronized floor-mounted force plate were collected during gait trials. Participants wore accelerometers to determine step counts for seven consecutive days. Dependent t-tests were used to identify differences in gait kinematics, kinetics and cumulative knee adductor load between groups. Compared to the healthy-weight participants, obese young adults demonstrated a slower walking speed, greater stance duration, less knee flexion at heel contact, greater knee adduction in early stance and less knee abduction at terminal stance (p < 0.05). The obese young adults had a greater external knee extension moment (p < 0.05) and external rotation moment (p < 0.05) in early stance. The obese group had a greater cumulative knee adductor load. These results provide insight into a potential pathway by which obesity predisposes a healthy young adult for knee osteoarthritis.This research is supported by Canada Research Chairs, Canadian Institutes of Health Research, and Natural Sciences and Engineering Research Council of Canad

Scalable parallel communications

Coarse-grain parallelism in networking (that is, the use of multiple protocol processors running replicated software sending over several physical channels) can be used to provide gigabit communications for a single application. Since parallel network performance is highly dependent on real issues such as hardware properties (e.g., memory speeds and cache hit rates), operating system overhead (e.g., interrupt handling), and protocol performance (e.g., effect of timeouts), we have performed detailed simulations studies of both a bus-based multiprocessor workstation node (based on the Sun Galaxy MP multiprocessor) and a distributed-memory parallel computer node (based on the Touchstone DELTA) to evaluate the behavior of coarse-grain parallelism. Our results indicate: (1) coarse-grain parallelism can deliver multiple 100 Mbps with currently available hardware platforms and existing networking protocols (such as Transmission Control Protocol/Internet Protocol (TCP/IP) and parallel Fiber Distributed Data Interface (FDDI) rings); (2) scale-up is near linear in n, the number of protocol processors, and channels (for small n and up to a few hundred Mbps); and (3) since these results are based on existing hardware without specialized devices (except perhaps for some simple modifications of the FDDI boards), this is a low cost solution to providing multiple 100 Mbps on current machines. In addition, from both the performance analysis and the properties of these architectures, we conclude: (1) multiple processors providing identical services and the use of space division multiplexing for the physical channels can provide better reliability than monolithic approaches (it also provides graceful degradation and low-cost load balancing); (2) coarse-grain parallelism supports running several transport protocols in parallel to provide different types of service (for example, one TCP handles small messages for many users, other TCP's running in parallel provide high bandwidth service to a single application); and (3) coarse grain parallelism will be able to incorporate many future improvements from related work (e.g., reduced data movement, fast TCP, fine-grain parallelism) also with near linear speed-ups

A Flexible System for Simulating Aeronautical Telecommunication Network

At Old Dominion University, we have built Aeronautical Telecommunication Network (ATN) Simulator with NASA being the fund provider. It provides a means to evaluate the impact of modified router scheduling algorithms on the network efficiency, to perform capacity studies on various network topologies and to monitor and study various aspects of ATN through graphical user interface (GUI). In this paper we describe briefly about the proposed ATN model and our abstraction of this model. Later we describe our simulator architecture highlighting some of the design specifications, scheduling algorithms and user interface. At the end, we have provided the results of performance studies on this simulator

Simultaneous 2D-Single Shot Imaging of OH Concentrations and Temperature Fields in a SI Engine Simulator

Two-dimensional (2D) temperature measurements in engines are required for the detailed understanding of the combustion process. Because of the unsteady and turbulent nature of engine combustion, these measurements must be performed on a single-shot basis to obtain cycle-resolved results. Details of the flame front structure are also important to know for the numerical modeling of internal combustion processes. Simultaneous measurements of temperature and hydroxyl radical distributions provide such data sets. The combustion of methane in a fully transparent square piston engine was studied with a combination of 2D laser-induced fluorescence of hydroxyl radicals and 2D Rayleigh scattering. A tunable KrF excimer laser at 248 nm was used for the measurementsThe wavelength of the laser was tuned to excite the P2(8) transition in the OH (3,0) band of the A-X system. Spectral filtering of the resulting fluorescence to detect solely the fluorescence from the (3,2) band significantly reduces the effect of collisional quenching imposed to the fluorescence to the predissociating v_=3 level by vibrational energy transfer (VET) to lower vibrational levels. Using a second camera, which only records the Rayleigh signals after appropriate filtering, allows the simultaneous measurement of temperature fields with a single laser. The analysis of corresponding OH and temperature images allowed the decision that the combustion conditions are in a regime where the flamelet approach for modeling is appropriate. Good agreement with model predictions has been achieved for the peak temperatures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86753/1/Sick49.pd

Use of multiple biomarkers for evaluation of anthracycline-induced cardiotoxicity in patients with acute myeloid leukemia

To assess cardiac toxicity of anthracycline treatment with six biomarkers of cardiac injury: myoglobin, creatine kinase MB (CK-MB mass), cardiac troponin T (cTnT), cardiac troponin I (cTnI), heart-type fatty acid binding protein (H-FABP), glycogen phosphorylase BB (GPBB). Methods: We evaluated anthracycline-induced cardiotoxicity in 12 acute myeloid leukemia patients (mean age 51.3 ± 10.7 years, 7 females). All biomarkers were measured at the baseline, after first chemotherapy (CT) with anthracyclines, after last CT with anthracyclines (total cumulative dose 479.8 ± 106.2 mg/m2) and 6 months thereafter. Values above the reference range were considered elevated. Results: GPBB increased above the cut-off (7.30 µg/L) in 2 (16.7%) patients after first CT, in 3 (25.0%) patients after last CT and remained elevated in 2 (16.7%) patients within 6 months after CT. CTnI became elevated (above 0.40 µg/L) in 1 (8.3%) patient after first and last CT and within 6 months after CT. CTnT remained negative (below 0.01 µg/L) during CT in all patients. Six months after CT, delayed cTnT positivity was found in 1 (8.3%) patient. All patients with cTnI or cTnT positivity had elevated GPBB. Other biomarkers (myoglobin, CK-MB mass, H-FABP) remained within the reference range in all patients. Conclusion: Our preliminary results suggest that GPBB could be a new promising marker for detection of anthracycline-related cardiotoxicity and probably superior to cardiac troponins. The predictive value for development of cardiomyopathy in the future is not clear and will be evaluated during a prospective follow-up.Цель: провести оценку кардиотоксичности, вызываемой антрациклином, с помощью ряда биомаркеров поражения сердца: миоглобина, креатин-киназы MB (CK-MB mass), кардиального тропонина T (cTnT), кардиального тропонина I (cTnI), белка, связывающего жирные кислоты (H-FABP), и гликогенфосфорилазы BB (GPBB). Методы: оценку кардиотоксичности проводили у 12 больных острой миелоидной лейкемией (средний возраст — 51,3 ± 10,7 года, 7 женщин). Измерены начальные показатели всех биомаркеров, а также таковые после проведения первой и последней химиотерапии (ХT) антрациклинами (общая накопленная доза — 479,8 ± 106,2 мг/м2 ) и через 6 мес после завершения терапии. Значения выше начальных рассматривали как повышенные. Результаты: уровень GPBB превысил норму (7,30 µg/L) у 2 больных (16,7%) после первой ХT, у 3 (25,0%) — после последней ХT и оставался повышенным у 2 больных (16,7%) и через 6 мес после ХT. Уровень CTnI повысился (более 0,40 µg/L) у 1 больного (8,3%) после первой и последней ХT, а также и через 6 мес после ХT. Значения CTnT оставались в пределах нормы (ниже 0,01 µg/L) во время проведения CT у всех пациентов. Через 6 мес после ХT отдаленная положительная реакция на cTnT выявлена у 1 больного (8,3%). У всех пациентов с положительными cTnI или cTnT установлен повышенный уровень GPBB. Другие биомаркеры (миоглобин, CK-MB, H-FABP) оставались в пределах нормы у всех больных. Выводы: предварительные результаты, полученные в данном исследовании, позволяют предположить, что GPBB можно рассматривать как новый перспективный маркер для выявления кардиотоксичности, вызванной антрациклинами, и, возможно, превосходит предложенные ранее тропонины. Возможная прогностическая ценность этого маркера при развитии кардиомиопатии пока не установлена

The use of cardiac biomarkers in detection of cardiotoxicity associated with conventional and high-dose chemotherapy for acute leukemia

Aim: Monitoring of cardiotoxicity of conventional and high-dose chemotherapy (HD-CT) with multiple biomarkers of cardiac injury — glycogen phosphorylase BB (GPBB), heart-type fatty acid binding protein (H-FABP), cardiac troponins (cTnT, cTnI), creatine kinase MB (CK-MB mass), myoglobin. Methods: A total of 47 adult acute leukemia patients were studied — 24 patients treated with conventional CT containing anthracyclines (ANT) and 23 patients treated with HD-CT (myeloablative preparative regimen) followed by hematopoietic cell transplantation (HCT). Cardiac biomarkers were assessed prior to treatment (before CT/HD-CT), after first CT with ANT, after last CT with ANT in the first group, after HD-CT and after HCT in the second group. Values above the reference range were considered elevated. Results: Before CT/HD-CT, all biomarkers of cardiac injury were below the cut-offs in all patients. GPBB increased above the cut-off (7.30 μg/L) in 4 (16.7%) patients after first CT and in 5 (20.8%) patients after last CT with ANT. GPBB increased above the cut-off in 5 (21.7%) patients after HD-CT and remained elevated in 5 (21.7%) patients after HCT. CTnI became elevated (above 0.40 μg/L) in 2 (8.3%) patients after first and last CT with ANT. Both patients with cTnI positivity had elevated GPBB. Other tested biomarkers remained below the cut-offs during the study. Conclusion: Our results suggest that GPBB could become a sensitive biomarker for detection of acute cardiotoxicity associated with conventional CT containing ANT and HD-CT followed by HCT. The predictive value for development of cardiomyopathy in the future is not known and should be evaluated during a prospective follow-up. Based on our data, a larger prospective and multicenter study would be most desirable to define the potential role of new circulating biomarkers in the assessment of cardiotoxicity in oncology