Beitr?ge zur Kenntnis der Honigweine

Ohne Zusammenfassung     

Beitr?ge zur Kenntnis des russischen Honigs

Ohne ZusammenfassungMitteilung aus dem Landwirtschaftlich-Bakteriologischen Laboratorium des Ackerbauministeriums zu St. Petersburg (Direktor: M. G. Tartakowsky).     

On the synchronicity of flash sintering and phase transformation

There is growing evidence that oxides of complex chemistries can be formed in one step by reactive flash sintering of their elemental constituents. Here we explore the temporal relationship between phase transformation and sintering by combining measurements of sintering with in situ measurements of phase transformation. The experiments are carried out under current rate, where flash is induced by injecting current and increasing it at a constant rate. We show that phase transformation of powders of magnesia and α-alumina into single-phase magnesium aluminate spinel was completed in 45 seconds, whereas sintering to full density required 60 seconds.     

Catalytic conversion of Euphorbia neriifolia biocrude into petroleum hydrocarbons

The latex of Euphorbia neriifolia has been studied with a view to its development as a potential petrocrop. Hydrocracking of biocrude afforded 72% conversion to products (C₅ and larger molecules), comprising up to 35% gasoline (b.p. 65–150 °C) and 15% kerosene (150–260 °C) in addition to other products. About 70% of the hydrocarbon material present in the gasoline fraction has been characterized.     

Selection of a Set of Part Delivery Dates in a Multi-Job Stochastic Assembly System

The problem of determining part delivery dates in a low-volume assembly line manufacturing large and costly products is studied. At each workstation a part is assembled to the subassembly. These parts are supplied by external vendors with unreliable delivery schedules. The arrival date of a part is assumed to follow a normal distribution whose mean is to be specified. A dynamic programming approach in combination with a heuristic procedure is used to prescribe the vendor delivery dates for a batch of products. Simulation results show the procedure to be significantly superior to a deterministic approach to the problem. Comparisons are also made with a safety buffer method.     

Outcomes of vitrectomy for retained lens fragments

PURPOSE: Retained lens fragments after cataract surgery is an infrequent, but potentially serious surgical complication. The aim of this study is to evaluate outcomes after vitrectomy has been performed for removal of retained lens material. METHODS: A retrospective review was conducted to evaluate all cases of pars plana vitrectomy for removal of retained lens fragments performed at Wills Eye Hospital from April 1991 through August 1994. RESULTS: A total of 121 eyes of 121 patients underwent pars plana vitrectomy with removal of retained lens material over the 3 1/2-year period. Visual acuity on presentation was 20/200 or worse in 95 eyes (79 percent). Visual acuity after vitrectomy was 20/40 or better in 82 eyes (68 percent). The postoperative visual acuity was 20/50 to 20/400 in 21 eyes (17 percent), and counting fingers or worse in 18 eyes (15 percent). Nineteen eyes (16 percent) had retinal detachment (RD), 8 were noted at the time of vitrectomy and 11 occurred after vitrectomy. Of the 19 eyes with RD, visual acuity was 20/200 or worse in 12 (63 percent) and counting fingers or worse in 6 (32 percent) at the time of last follow-up. The use of posterior segment phacofragmentation was associated with higher rate of RD, but the difference did not reach statistical significance. Major causes of poor final visual outcome included RD (6 eyes), cystoid macular edema (4 eyes), and glaucoma (2 eyes). CONCLUSION: The timing of vitrectomy did not have a statistically significant impact on visual outcome. Neither the type of intraocular lens nor the timing of lens implantation significantly altered the final visual acuity. Most eyes with retained lens fragments do well after vitrectomy, with the majority recovering good vision. However, the risk of RD is increased, and visual outcome may be adversely affected if RD occurs.     

Measurement of O and Ti atom displacements in TiO2 during flash sintering experiments

In‐situ flash experiments on rutile TiO₂ were performed at the synchrotron at the Brookhaven National Laboratory. Pair distribution function analysis of total X‐ray scattering measurements yielded mean‐square atomic displacements of oxygen and titanium atoms during the progression of the 3 stages of flash. The displacements are measured to be far greater for oxygen atoms than for titanium atoms. These large displacements may signal an “elastic softening” of the lattice, which, recently, has been predicted as a precursor to the onset of flash.     

Dry sliding tribology of dioctyldithiophosphoric acid deposited on steel at 150 °C

Dioctyldithiophosphoric acid was deposited on 7 nm (RMS) rough steel surfaces at 150 °C to create a densely packed (area-95%) deposit of glassy phosphate islands of maximum 500 nm height. This standard substrate was subjected to dry lubricated ball-on-disc tribology using a 2 mm diameter steel ball in the 25–500 mN normal load range at a sliding velocity of 1 mm/s. The experiments recorded friction coefficient of the order of 0.18 but the life of the film as it wears out with sliding distance was found to decline with increasing load. The life–load characteristics that we record in these experiments, we argue, can only be explained if there is a load induced growth of the deposited film during sliding. We record this load induced growth to yield phosphate islands which are significantly smaller but harder than those grown by thermal activation alone.