High temperature oxidation mechanism of dilute copper aluminium alloys

Dilute copper-aluminium alloys were oxidized in air from 700 to 1000 °C. Two distinctive behaviours were observed: alloys with at least 3 wt% aluminium showed excellent oxidation resistance in the whole temperature range. Alloys with 2 wt% or less aluminium exhibited good oxidation resistance up to 800 °C; but as the temperature was further increased, the oxidation rate of these alloys increased and became comparable to that of pure copper. A kinetic model was developed to explain the oxidation behaviour and indirectly determine the amount of dissolved oxygen in the alloys tested. It was found that the oxygen dissolved in alloys with up to 2 wt% Al exceeded its solubility limit in copper, whereas the dissolved oxygen in alloys with higher aluminium contents was below the solubility limit. This difference may account for the significantly different oxidation resistance.     

Study on the Complementation of Two Proteins of Low Quality: Black Bean (Phaseolus vulgaris) and Sesame (Sesamun incdicum L.).

In order to determine the complementary potential of black bean and sesame proteins, female rats were fed diets with 10% protein from black bean, sesame or combinations of these. Data showed that diets with these proteins combined had better quality than either protein alone. Maximum protein quality was observed when the two protein sources were mixed in a 1:l (w/w) ratio. This mixturn had PER and NPR values 2 and 5 times higher, respectively, than those of the black bean protein alone and 61 and 71% of the values of PER and NPR, respectively, obtained with a casein diet. Also, there was no alteration of serum or liver lipids.     

PROTEOLYSIS IN SALMON (SALMO SALAR) DURING COLD STORAGE; EFFECTS OF STORAGE TIME AND SMOKING PROCESS

Changes in free amino acids (FAAs), small peptides and myofibrillar proteins were investigated in salmon (Salmo salar) muscle stored at OC for up to 23 days and after the stored salmon was smoked. Storage time and smoking process did not increase the formation of FAAs and small peptides indicating low exopeptidase activity. During storage, SDS PAGE analysis of myofibrils showed an increase in density of bands at 16, 37, 60, 64, 67, 76 and 130 kDa, a decrease of a 32 kDa band and the appearance of four new bands of 30, 90, 95 and 113 kDa. These results indicate proteolytic degradation. A little change of myosin and no change of α‐actinin and actin were observed. The smoking process itself enhances the intensity of bands, but does not change the pattern markedly except for the appearance of a 25 and 70 kDa band. Degradation pattern after smoking was not affected by storage time.     

The reduction of Tokyo and Sinter 75 nickel oxides with hydrogen

Industrial Tokyo and Sinter 75 nickel oxides were reduced with 35 and 80% volume hydrogen-argon mixtures between 350 and 1000 °C in a TGA apparatus. Several abnormalities were observed. At low temperature and in 35% H₂, an incubation period was observed. As the temperature was increased the rate of reduction increased up to some temperature, following which a decrease in the reaction rate was observed, which again was followed by an increase in the rates as the temperature exceeded 900 °C. It was found that reduction kinetics of these oxides strongly depend on the morphological features of the oxides. It became clear that the shrinking core model was not applicable and instead the kinetic parameters were assessed by the grain model.     

THE CONTACT HYPOTHESIS IN URBAN CHINA: THE PERSPECTIVE OF MINORITY‐STATUS MIGRANT WORKERS

ABSTRACT: This study is the first to test Allport's (1954) contact hypothesis from the perspective of a minority group in China. Employing a sample of off‐farm migrant workers in urban China, results indicate a positive effect on self‐reported attitudes of intergroup friendship contact between migrant and local workers; and positive effects on self‐reported behavioral interaction between migrants and urban locals of both intergroup friendship and intergroup nonfriendship contact.     

Inflow shortages in deregulated power markets — Reasons for concern?

In many countries hydropower constitutes a large share of the electricity producing capacity. In the earlier regulated electricity markets, production capacities exceeded demand due to security of supply concerns. The present deregulated markets base investments upon profitability alone, and security of supply issues are claimed to be less important. Market operators trust the pricing mechanism in competitive markets to clear. Then low inflow constitutes a less problem. Several markets, both under regulated and deregulated regimes, have faced serious droughts. Some of them have experienced problems with market clearance (Chile, Brazil, California) while other markets functioned well (The Nordic market). Important features to the market response are the flexibility of demand, the pattern of inflow shortage, the storage capacities, the possibility of trade between regions with different production technologies, and the market design and concentration. We apply an empirical based market model to simulate the effects under two inflow shortage scenarios in an international market with combined hydro and thermal capacities and restricted transmission capacities. We compare the scenarios with actual events and show that the model and the real market outcome are comparable. The simulations do not reveal any problems with the functioning of the market, which should calm down the anxiousness about security of supply in deregulated markets with stochastic energy supply.     

The efficiency of systematic sampling in stereology — reconsidered

In the present paper, we summarize and further develop recent research in the estimation of the variance of stereological estimators based on systematic sampling. In particular, it is emphasized that the relevant estimation procedure depends on the sampling density. The validity of the variance estimation is examined in a collection of data sets, obtained by systematic sampling. Practical recommendations are also provided in a separate section.