The essence of the getting popular online group-buying activities in the Internet age is that the price of products depends on the quantity of orders. The more the orders are gathered, the lower prices we can get. In addition, the price is always a major concern of consumers in shopping. Thus, the accumulated number of orders is of concern to the initiator and all consumers. In the past, some scholars also found the phenomenon of demand externalities. It indicates that the larger the existing orders are, the more consumers will join the group-buying. On the contrary, it is not easy to attract consumers to join the group-buying. So, if the number of orders increases fast and therefore generates the effect of demand externalities, the performance of group-buying will be improved. Therefore, this research, based the concept of free-options price promotion, explored if the quantity-based price promotion will affect the consumers¡¦ perceived value and intention to join the group-buying. Besides, the research also explored if the product preservation will moderate the effect of quantity-based price promotion on the consumers¡¦ perceived value. In this research, the quantity-based price promotion was manipulated as ¡§Buy five and get one free¡¨ in the experiment. A field experiment was done on NeGoGo group-buying website first. Then, based on the observation of the field experiment, an online experiment was designed and implemented. The result found that consumers have greater perceived value on price and emotion in a group-buying with quantity-based price promotion, but there is no interference effect of product preservation. Furthermore, when consumers have greater perceived value on price and emotion, their intention to join group-buying will be higher. Finally, compared to a group-buying with no price promotion, the average consumers¡¦ purchased quantity of group-buying with quantity-based price promotion is significantly higher. In other words, the quantity-based price promotion can improve the performance of group-buying transaction.

The aim of the diploma thesis was determined the particular fatty characteristics of various vegetable oils in dependence on their storage life and storage conditions. Storage conditions were defined by room temperature and coolroom temperature. The fourteen oils were used for analyses, namely linseed oils, castor oil, grape seed oil, almond oil, olive oil, jojoba oil, avocado oil, apricot kernel oil, corn oil, rice bran oil, macadamia nut oil, soya bean oil, pumpkin seed oil and sunflower oil. All tested oils were supplied by firm M+H, Míča a Harašta s.r.o. The fatty characteristics included the saponification value, the acid value, the iodine value and the thiobarbituric value. The ester values and the percentage glycerol content were counted on the basis of the saponification value and the acid value. Time dependences of all fatty characteristics were figured to graphs and they were compared on various storage conditions. The fatty characteristics indicated lower values in storage of oil samples in coolroom than at laboratory temperature.

This project examines whether there is a direct link between respiration and the rate of senescence of fresh produce. Treatments that increase the storage life of fresh products, such as cooling, modified atmospheres and semi-permeable coatings, often decrease respiration rates. This suggests that it may be possible to assess the effectiveness of a specific storage treatment in terms of its effect on reducing respiration. If this is so, total respiration during storage should sum to a constant regardless of changes in the storage conditions. Such an equivalence between 'respiration life' and storage life has been demonstrated in only a few cases. Respiration data from a wide range of published work was analysed from the viewpoint of testing this hypothesis. In general, the results were positive, with some reservations that were further investigated by experiment. In conclusion, respiration rate may be a guide to storage life for products that have clearly defined stages of senescence, and for which rots are not the primary cause of the end of acceptability. The development of the respirometer should make it possible to examine this relationship for many other commodities. However, while respiration may be a function of the rate of senescence under some circumstances, it is also affected by other factors. These include photosynthesis, attachment to the plant, and permeance to gases. Directions for future work therefore include the contribution of photosynthesis to fruit development, the effects of ethylene on respiration rates of non-climacteric fruit while attached to the plant, and interactions between ethylene synthesis and disease resistance / Doctor of Philosophy (PhD)

Solid propellant rocket motor is the primary propulsion technology used for short and medium range missiles. It is also commonly used as boost motor in many di_erent applications. Its wide spread usage gives rise to diversity of environments in which it is handled and stored. Ability to predict the storage life of solid propellants plays an important role in the design and selection of correct protective environments. In this study a methodology for the prediction of solid propellant storage life using cumulative damage concepts is introduced. Finite element mesh of the solid propellant grain is created with the developed parametric grain geometry generator. Finite element analyses are carried out to obtain the temperature and stress response of the propellant to the environmental thermal loads. Daily thermal cycles are assumed to be sinusoidal cycles represented by their means and amplitudes. With the cumulative damage analyses, daily damage accumulated in the critical locations of the solid propellant grain are investigated. Meta-models relating the daily damage amount with the daily temperature cycles are constructed in order to compute probability of failure. The results obtained in this study imply that it is possible to make numerical predictions for the storage life of solid propellants even in the early design phases. The methodology presented in this study provides a basis for storage life predictions.