Transition region ignition characteristics of n-heptane fuel sprays

Ignition studies were perferred on monodisperse n-heptane sprays at atmospheric pressure over a range of equivalence ratios and droplet diameters. A capacitive discharge spark ignition system was used as the ignition source, providing independent control of spark energy and duration. Preliminary measurements were made to optimize spark duration and spark gap, optimum conditions being those at which the maximum frequency or probability of ignition was observed. The effect of spark duration on ignition frequency for several spark energies was determined for equivalence ratios of 0.5 and 1.0 and initial droplet diameters of 28 and 68 microns. Spark duration had little effect on ignition frequency over the entire 15 to 170 mu s range examined. Spark durations of 70 to 80 mu s were used for all subsequent work. The spark gap was optimized at equivalence ratios of 0.6, 0.8 and 1.0 and initial droplet diameters of 30, 40, 50, 60 and 70 microns by varying the electrode spacing from 0.5 to 5.0 mm while maintaining a constant spark energy. The optimum gap was determined to be 3.0 mm for nearly all conditions

Spark Ignition of Monodisperse Fuel Sprays

A study of spark ignition energy requirements was conducted with a monodisperse spray system allowing independent control of droplet size, equivalent ratio, and fuel type. Minimum ignition energies were measured for n-heptane and methanol sprays characterized at the spark gap in terms of droplet diameter, equivalence ratio (number density) and extent of prevaporization. In addition to sprays, minimum ignition energies were measured for completely prevaporized mixtures of the same fuels over a range of equivalence ratios to provide data at the lower limit of droplet size. Results showed that spray ignition was enhanced with decreasing droplet size and increasing equivalence ratio over the ranges of the parameters studied. By comparing spray and prevaporized ignition results, the existence of an optimum droplet size for ignition was indicated for both fuels. Fuel volatility was seen to be a critical factor in spray ignition. The spray ignition results were analyzed using two different empirical ignition models for quiescent mixtures. Both models accurately predicted the experimental ignition energies for the majority of the spray conditions. Spray ignition was observed to be probabilistic in nature, and ignition was quantified in terms of an ignition frequency for a given spark energy. A model was developed to predict ignition frequencies based on the variation in spark energy and equivalence ratio in the spark gap. The resulting ignition frequency simulations were nearly identical to the experimentally observed values

Pengaruh Sanksi Administrasi dan Surat Paksa terhadap Optimalisasi Pencairan Tunggakan Pajak (Studi pada Kantor Pelayanan Pajak Pratama Singosari)

The trust given by the government to taxpayers in self-assessment system should be able to run well according to the plan. Taxpayers are capable for performing their tax duty well and properly without negligence, deliberateness, and ignorance concerning this duty. In order to minimize these actions, there should be law enforcement in the obedience of the taxpayers. This study is aimed to (1) Know whether the administration charge and distress warrant has significant effects on the optimization of Disbursement of Tax Arrears. (2) Analyze and explain whether the administration charge has partially significant effects on the optimization of Disbursement of Tax Arrears, and (3) Analyze and explain whether the distress warrant has partially significant effects on the optimization of Disbursement of Tax Arrears.The kind of study used in this research is quantitative study, which is used to test hypothesis about the effects of the administration charge and distress warrant on the optimization of Disbursement of Tax Arrears. The population in this study is Taxpayers who receive administration charge and distress warrant and have tax arrears in Small Tax Office Singosari.The result of this study exclaimed that administration charge and distress warrant Variables have simultaneously significant effects on the optimization of Disbursement of Tax Arrears. Partially, administration charge and distress warrant Variables havesignificant effects on the optimization of Disbursement of Tax Arrears. It is suggested for the next researchers to employ other variables that affect the optimization of Disbursement of Tax Arrears, which are taxpayers, awareness, criminal sanctions, and so on to improve the study

Menstrual disturbances in perimenopausal women: What's best?

It's best to start with nonsteroidal anti- inflammatory drugs (NSAIDs), which effectively reduce heavy menstrual bleeding (strength of recommendation [SOR]: B, systematic review of randomized clinical trials [RCTs]). Perimenopausal women with heavy bleeding not controlled by NSAIDs, or other forms of dysfunctional uterine bleeding, can benefit from continuous, combined hormonal therapy with estrogen and progestin; hormonal therapy with estrogen and a cyclical progestin; or a cyclical progestin alone (SOR: B, RCTs and a systematic review of RCTs). Intrauterine devices (IUDs) containing levonorgestrel also effectively reduce bleeding and may avoid surgical intervention (SOR: B, systematic review of RCTs)

Association of Systemic Inflammation With Retinal Vascular Caliber in Patients With AIDS.

PurposeTo evaluate relationships among retinal vascular caliber and biomarkers of systemic inflammation in patients with AIDS.MethodsA total of 454 participants with AIDS had retinal vascular caliber (central retinal artery equivalent and central retinal vein equivalent) determined from enrollment retinal photographs by reading center graders masked to clinical and biomarker information. Cryopreserved plasma specimens were assayed for inflammatory biomarkers, including C-reactive protein (CRP), IL-6, interferon-γ inducible protein (IP)-10, kynurenine/tryptophan (KT) ratio, and intestinal fatty acid binding protein (I-FABP).ResultsIn the simple linear regression of retinal vascular caliber on plasma biomarkers, elevated CRP, IL-6, and IP-10 were associated with retinal venular dilation, and elevated KT ratio with retinal arteriolar narrowing. In the multiple linear regression, including baseline characteristics and plasma biomarkers, AMD was associated with dilation of retinal arterioles (mean difference: 9.1 μm; 95% confidence interval [CI] 5.2, 12.9; P < 0.001) and venules (mean difference, 10.9 μm; 95% CI, 5.3, 16.6; P < 0.001), as was black race (P < 0.001). Hyperlipidemia was associated with retinal venular narrowing (mean difference, -7.5 μm; 95% CI, -13.7, -1.2; P = 0.02); cardiovascular disease with arteriolar narrowing (mean difference, -5.2 μm; 95% CI, -10.3, -0.1; P = 0.05); age with arteriolar narrowing (slope, -0.26 μm/year; 95% CI, -0.46, -0.06; P = 0.009); and IL-6 with venular dilation (slope, 5.3 μm/standard deviation log10[plasma IL-6 concentration]; 95% CI, 2.7, 8.0; P < 0.001).ConclusionsThese data suggest that retinal vascular caliber is associated with age, race, AMD, hyperlipidemia, cardiovascular disease, and selected biomarkers of systemic inflammation

Recursiveness, Switching, and Fluctuations in a Replicating Catalytic Network

A protocell model consisting of mutually catalyzing molecules is studied in order to investigate how chemical compositions are transferred recursively through cell divisions under replication errors. Depending on the path rate, the numbers of molecules and species, three phases are found: fast switching state without recursive production, recursive production, and itinerancy between the above two states. The number distributions of the molecules in the recursive states are shown to be log-normal except for those species that form a core hypercycle, and are explained with the help of a heuristic argument.Comment: 4 pages (with 7 figures (6 color)), submitted to PR