Neue Apparate

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Ueber die Capillaritätsconstanten von Salzen beim Schmelzpunkt

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Automobile rear signal lamps: Effect of realistic levels of dirt on light output

This study evaluated changes in the light output of rear signal lamps as a function of dirt accumulated during a 482 km drive, representing ten days' driving for a typical United States driver. The complete route was traversed on three separate occasions, under each of the following environmental conditions: dry, wet, and snowy/salty. Luminous intensity measurements were obtained for all US and European test points. Photometry for each of two stop lamps was performed twice after the completion of each drive: first 'as is' and then after cleaning. The results indicate that dirt deposits tended to cause the light output to decrease at the points tested. The reductions after the dry drive were all less than 8%. However, after the wet and snowy/salty drives reductions of more than 25% occurred at several test points, with a maximum reduction of 37%. The test percentage reductions occurred for the points at and near the optical axes of the lamps, which had the highest original intensities, and at which maintaining adequate intensity is presumably most important. A theoretical analysis of the changes caused by dirt indicates that this is the pattern of results that wild usually occur. A full evaluation of the significance of the effects of dirt that are quantified in this paper should be done in the context of other factors that affect signal-lamp intensity, such as vehicle voltage control and lamp design. It may also be important to measure more fully the range and distributions of dirt conditions in the real world. However, the present results demonstrate that, within the range of common weather conditions, dirt can cause reductions of signal-lamp intensity that are large enough to be of concern, especially for the relatively important positions at and near the optical axes of signal lamps.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68399/2/10.1177_096032719803000104.pd

Do changes in voltage result in proportional changes throughout headlamp beam pattern?

This study evaluated the effects of voltage changes on beam patterns of low-beam headlamps. Seven different types of filament lamps were tested. The voltages used were 12.0, 12.8 and 13.5V. The photometry was performed from 20° left to 20° right, and from 5° down to 5° up, all in steps of 0.5°. The main finding of this study is that, for all seven lamps tested, voltage changes between 12.0V and 13.5V caused light output to change by the same proportion throughout the beam pattern. Therefore, for filament lamps, it is reasonable to use a single constant for all values in a beam pattern when converting a headlighting specification at one voltage to a specification at a different voltage, at least if the voltages in question are between 12.0 V and 13.5 V. The constants obtained across the seven lamps tested were similar to each other. Furthermore, these constants were in general agreement with the constants derived using the standard IES formula relating light-output changes to voltage changes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68799/2/10.1177_096032719903100101.pd

Evaluations of in-traffic performance of high-intensity discharge headlamps

This study evaluated subjects' impressions of performance of high-intensity discharge (HID) headlamps after in-traffic experience, with an emphasis on colour appearance of red stop signs. In the first of two tasks, subjects drove (or rode) for half an hour on a variety of roads in a car equipped with either HID or tungsten-halogen low-beam headlamps. Instructions did not mention colour appearance. The second task involved a direct comparison of HID and tungsten-halogen headlamps. In this task, subjects drove (or rode) twice along a 7-minute route in a residential area, and they were instructed to pay attention to the colour appearance of stop signs and other objects. The main finding from Task 1 is that subjects who experienced HID headlamps did not report more (or fewer) spontaneous negative comments on colour appearance of stop signs or other objects than did subjects who experienced tungsten-halogen headlamps. Furthermore, the evaluations of the overall performances of the two types of headlamps were not different. In the direct comparison of Task 2 there was no evidence of problems with colour appearance when using HID headlamps. Moreover, subjects preferred HID headlamps in terms of the overall performance, and in making stop signs and other objects stand out from their background. However, this preference for HID headlamps was present only for subjects who had the relatively extended exposure to the HID headlamps in Task 1. The present results provide no evidence for problems with colour appearance of stop signs and other objects when using HID headlamps. Furthermore, the study provides evidence that observers perceive HID headlamps as helping stop signs and other objects to stand out from their background. The results imply that given a somewhat extended exposure to HID headlamps, drivers would prefer them over current tungsten-halogen headlamps.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68417/2/10.1177_096032719402600402.pd

Do changes in voltage result in proportional changes throughout headlamp beam patterns?

This study evaluated the effects of voltage changes on beam patterns of low-beam headlamps. Seven different types of filament lamps were tested. The voltages used were 12.0, 12.8, and 13.5 V. The photometry was performed from 20° left to 20° right, and from 5° down to 5° up, all in steps of 0.5°. The main finding of this study is that for all seven lamps tested, voltage changes between 12.0 V and 13.5 V caused light output to change by the same proportion throughout the beam pattern. Therefore, for filament lamps, it is reasonable to use a single constant for all values in a beam pattern when converting a headlighting specification at one voltage to a specification at a different voltage, at least if the voltages in question are between 12.0 V and 13.5 V. The obtained constants across the seven lamps tested were similar to each other. Furthermore, these constants were in general agreement with the constants derived by using the standard IES formula relating light-output changes to voltage changes.Michigan University, Ann Arbor, Industry Affiliation Program for Human Factors in Transportation Safetyhttp://deepblue.lib.umich.edu/bitstream/2027.42/49379/1/UMTRI-98-27.pd

The influence of sun loading on the visibility of clear-lens turn signals

There is some concern that turn signal lamps with clear outer lenses make it difficult in bright, sunny conditions to decide whether the signal is on or not. Two studies were performed. The first study was a survey of current practice in the U.S. with regard to the use of clear-lens turn signal lamps. The main results are that clear outer lenses on rear turn signal lamps are used in about 28% of all vehicle models, while the corresponding percentage for front turn signal lamps is about 70%. The second study photometrically evaluated, under bright, sunny conditions, both luminance contrast and color contrast between the on and off states for turn signal lamps that use either an amber lens or a clear lens. The results indicate that luminance contrast between the on and off states is greater for lamps using an amber lens. On the other hand, the results indicate that color contrast between the on and off states is greater for lamps using a clear lens. Because luminance contrast is likely to be the primary variable influencing driver performance, these results suggest that using clear-lens turn signal lamps is likely to make it more difficult to determine, in bright, sunny conditions, whether the signal is on or not. However, the magnitude of the decrement in real-world performance with clear-lens signal lamps remains to be ascertained.Michigan University, Ann Arbor, Industry Affiliation Program for Human Factors in Transportation Safetyhttp://deepblue.lib.umich.edu/bitstream/2027.42/49364/1/UMTRI-98-2.pd

Epigenetic Anti-Cancer Treatment With a Stabilized Carbocyclic Decitabine Analogue

5-Aza-2'-deoxycytidine (Decitabine, AzadC) is a nucleoside analogue, which is in clinical use to treat patients with myelodysplastic syndrome or acute myeloid leukemia. Its mode of action is unusual because the compound is one of the few drugs that act at the epigenetic level of the genetic code. AzadC is incorporated as an antimetabolite into the genome and creates covalent, inhibitory links to DNA methyltransferases (DNMTs) that methylate 2'-deoxycytidine (dC) to 5-methyl-dC (mdC). Consequently, AzadC treatment leads to a global loss of mdC, which presumably results in a reactivation of silenced genes, among them tumor suppressor and DNA damage response genes. Because AzadC suffers from severe instability, which limits its use in the clinic, a more sophisticated AzadC derivative would be highly valuable. Here, we report that a recently developed carbocyclic AzadC analogue (cAzadC) blocks DNMT1 in the AML cell line MOLM-13 as efficient as AzadC. Moreover, cAzadC has a surprisingly strong anti-proliferative effect and leads to a significantly higher number of double strand breaks compared to AzadC, while showing less off-target toxicity. These results show that cAzadC triggers more deleterious repair and apoptotic pathways in cancer cells than AzadC, which makes cAzadC a promising next generation epigenetic drug