A study of invert emulsion drilling fluids

Since invert emulsions are being applied as drilling fluids to cope with special drilling and completion problems, evaluations of existing and new types of emulsions are needed. Three types of emulsions are evaluated in this study: (1) type A emulsions prepared with a commercial emulsifier, (2) type B emulsions prepared by adding clay to the external phase, and (3) type C emulsions containing no externally added emulsifier. Standard testing procedures were used to measure the viscosity and filtration properties of the emulsions studied. Interfacial tension measurements were made using a technique described in the literature. The degree of stability for the emulsions studied was determined by the viscosity ratio method developed during this study. A discussion of the effects of some of the recognized variables on the properties mentioned above is presented. The three types of emulsions studied are compared on the basis of the effects of the variables and on theoretical considerations. Type A emulsions as investigated were found to be suitable for all conditions under which the use of an invert emulsion fluid is warranted. Type B emulsions as investigated were found to be suitable only over a narrow range of temperatures and phase volume ratios. Type C emulsions exhibited excessive filter losses over all phase volume ratios investigated and were eliminated from further consideration on this basis --Abstract, page ii

Eukaristisk diakoni. Refleksjonar kring Den ortodokse kyrkjas diakonale profil og utfordringar i diasporaen i dag

Dette arbeidet er skrive som ein refleksjonar kring Den ortodokse kyrkjas diakonale profil og utfordringar i diasporaen i dag. Utgangspunktet ligg i hovudproblemstillinga: Kvifor blir liturgien vektlagt så sterkt i Den ortodokse kyrkja, og kva følgjer får den liturgiske sentreringa med omsyn til diakonal profil? Gjennom ei samanstilling av ulike litterære kjelder byggjer ein i oppgåveteksten opp ein teologisk, historisk, samfunnsmessig og religionssosiologisk bakgrunnsmatrise for analysen og drøftinga av eit innsamla munnleg kjeldemateriale. Fire ortodokse kyrkjelydsprestar er informantar i denne studien

Red deer bone and antler collagen are not isotopically equivalent in carbon and nitrogen

RATIONALE: Bone and antler collagen δ(13) C and δ(15) N values are often assumed to be equivalent when measured in palaeodietary, palaeoclimate and palaeocological studies. Although compositionally similar, bone grows slowly and is remodelled whereas antler growth is rapid and remodelling does not occur. These different patterns of growth could result in isotopic difference within antler and between the two tissue types. Here we test whether red deer (Cervus elaphus) bone and antler δ(13) C and δ(15) N values are equivalent, and whether intra-antler isotopic values are uniform. METHODS: Bone and antler were isotopically analysed from six stags that lived in a temperate maritime climate on the Isle of Rum, Scotland. Multiple antlers from different years were sampled per individual, together with a single bone sample per individual. Up to 12 samples were taken along the length of each antler (total of 25 antlers, 259 samples) so that a chronological record of the isotopic composition during antler growth could be obtained. Collagen was extracted and its δ(13) C and δ(15) N values were measured by continuous-flow isotope ratio mass spectrometry. RESULTS: Intra-antler collagen isotope signatures vary, and show that not all antlers from an individual or a growth year are equivalent in carbon and nitrogen isotopic ratios. δ(15) N values typically increase with distance along antler length, but no overall trend is observed in δ(13) C values. An isotopic offset is visible between bone and antler, with bone δ(13) C and δ(15) N values being higher in most cases. CONCLUSIONS: Bone and antler collagen δ(13) C and δ(15) N values are not isotopically equivalent and are therefore not directly comparable in palaeodietary, palaeoclimate and palaeocological studies. Bone and antler collagen isotopic differences probably relate to differential metabolic processes during the formation of the two tissues. Intra- and inter-antler isotopic variations probably reflect the isotopic composition of an individual's diet rather than physiological parameters, and may have the potential to provide high-resolution individual-specific information in modern and ancient cervid populations

Pitaria ida, a new recent species from Sitka, Alaska

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