University of Massachusetts Amherst

About: University of Massachusetts Amherst is a education organization based out in Amherst Center, Massachusetts, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 37274 authors who have published 83965 publications receiving 3834996 citations. The organization is also known as: UMass Amherst & Massachusetts State College.

Nanoemulsions versus microemulsions: terminology, differences, and similarities

Abstract: Colloidal delivery systems based on microemulsions or nanoemulsions are increasingly being utilized in the food and pharmaceutical industries to encapsulate, protect, and deliver lipophilic bioactive components. The small size of the particles in these kinds of delivery systems (r < 100 nm) means that they have a number of potential benefits for certain applications: enhanced long-term stability; high optical clarity; and, increased bioavailability. Currently, there is considerable confusion about the use of the terms “microemulsions” and “nanoemulsions” in the scientific literature. However, these are distinctly different types of colloidal dispersions: a microemulsion is thermodynamically stable, whereas a nanoemulsion is not. It is therefore important to distinguish between them since this impacts the methods used to fabricate them, the strategies used to stabilize them, and the approaches used to design their functional attributes. This article reviews the differences and similarities between nanoemulsions and microemulsions in terms of their compositions, structure, fabrication, properties, and stability. It also attempts to highlight why there has been so much confusion in this area, and to clarify the terminology used to refer to these two kinds of colloidal dispersion.

Modeling TCP Reno performance: a simple model and its empirical validation

Abstract: The steady-state performance of a bulk transfer TCP flow (i.e., a flow with a large amount of data to send, such as FTP transfers) may be characterized by the send rate, which is the amount of data sent by the sender in unit time. In this paper we develop a simple analytic characterization of the steady-state send rate as a function of loss rate and round trip time (RTT) for a bulk transfer TCP flow. Unlike the models of Lakshman and Madhow (see IEE/ACM Trans. Networking, vol.5, p.336-50, 1997), Mahdavi and Floyd (1997), Mathis, Semke, Mahdavi and Ott (see Comput. Commun. Rev., vol.27, no.3, 1997) and by by Ott et al., our model captures not only the behavior of the fast retransmit mechanism but also the effect of the time-out mechanism. Our measurements suggest that this latter behavior is important from a modeling perspective, as almost all of our TCP traces contained more time-out events than fast retransmit events. Our measurements demonstrate that our model is able to more accurately predict TCP send rate and is accurate over a wider range of loss rates. We also present a simple extension of our model to compute the throughput of a bulk transfer TCP flow, which is defined as the amount of data received by the receiver in unit time.