Crystallization Kinetics of Amorphous Lactose as a Function of Moisture Content Using Isothermal Differential Scanning Calorimetry

Isothermal differential scanning calorimetry (DSC) was used to study the crystallization kinetics of amorphous lactose at 3 moisture contents. Each sample was heated to several temperatures between Tg and Tm. After subtraction of an induction time, the Avrami equation was used to model the data and a Lauritzen-Hoffman like expression used to fit the crystallization rates between Tg and Tm. The highest Tm/Tg ratio and crystallization rate were observed for the sample containing the most moisture. Conversely the lowest Tm/Tg ratio and crystallization rate were observed for the sample containing the least moisture. Evidence for multiple transitions was seen. The Avrami equation may not be the best way to model such data.     

A 10-Gb/s 1024-Way-Split 100-km Long-Reach Optical-Access Network

Optical-access networks have been developed to remove the access-network bandwidth bottleneck. However, the current solutions do not adequately address the network economics to provide a truly cost-effective solution. Long-reach optical-access networks introduce a cost-effective solution by connecting the customer directly to the core network, bypassing the metro network, and, hence, removing significant cost. This paper charts the design and development of a 1024-way-split 100-km 10-Gb/s symmetrical network, which experimentally proves the feasibility of long-reach optical-access networks for both the upstream and downstream transmission.     

Development of highly oriented polymer crystals from row assemblies

The development of organized structures from sheared isotactic polypropylene melts with different amounts of dibenzylidene sorbitol (DBS) as a nucleating agent has been followed in real time using small angle X-ray scattering in conjunction with synchrotron radiation. The results show that, above a certain DBS concentration threshold, the lamellar crystals are highly oriented perpendicular to the direction of the prior applied shear field. The role of the directing agent in nucleating the crystallization and templating the crystal anisotropy is discussed.     

Partial Key Recovery Attack Against RMAC

In this paper new “partial” key recovery attacks against the RMAC block cipher based Message Authentication Code scheme are described. That is we describe attacks that, in some cases, recover one of the two RMAC keys much more efficiently than previously described attacks. Although all attacks, but one, are of no major threat in practice, in some cases there is reason for concern. In particular, the recovery of the second RMAC key (of k bits) may only require around 2^k/2 block cipher operations (encryptions or decryptions). The RMAC implementation using triple DES proposed by NIST is shown to be very weak.     

Mathematical Models of the Common-Source and Common-Gate Amplifiers Using a Metal-Ferroelectric-Semiconductor Field Effect Transistor

Mathematical models of the common-source and common-gate amplifiers using metal-ferroelectric-semiconductor field effect transistors (MFSFETs) are developed in this paper. The models are compared against data collected with MFSFETs of varying channel lengths and widths, and circuit parameters such as biasing conditions are varied as well. Considerations are made for the capacitance formed by the ferroelectric layer present between the gate and substrate of the transistors. Comparisons between the modeled and measured data are presented in depth.     

Extended Characterization of the Common-Source and Common-Gate Amplifiers Using a Metal-Ferroelectric-Semiconductor Field Effect Transistor

Collected data for both common-source and common-gate amplifiers is presented in this paper. Characterizations of the two amplifier circuits using metal-ferroelectric-semiconductor field effect transistors (MFSFETs) are developed with wider input frequency ranges and additional device sizes compared to earlier characterizations. The effects of the ferroelectric layer's capacitance and variation of load, quiescent point, or input signal on each circuit are shown. Advantages and applications of the MFSFET and the circuit performance are discussed.     

Pre‐College Engineering Studies: An Investigation of the Relationship Between Pre‐college Engineering Studies and Student Achievement in Science and Mathematics

Background The U.S. has experienced a shift from a manufacturing‐based economy to one that overwhelmingly provides services and information. This shift demands that technological skills be more fully integrated with one's academic knowledge of science and mathematics so that the next generation of engineers can reason adaptively, think critically, and be prepared to learn how to learn. Purpose (Hypothesis ) Project Lead the Way (PLTW) provides a pre‐college curriculum that focuses on the integration of engineering with science and mathematics. We documented the impact that enrollment in PLTW had on student science and math achievement. We consider the enriched integration hypothesis, which states that students taking PLTW courses will show achievement benefits, after controlling for prior achievement and other student and teacher characteristics. We contrast this with alternative hypotheses that propose little or no impact of the engineering coursework on students' math and science achievement (the insufficient integration hypothesis), or that PLTW enrollment might be negatively associated with student achievement (the adverse integration hypothesis). Design/ Method Using multilevel statistical modeling with students (N = 140) nested within teachers, we report findings from a quantitative analysis of the relationship between PLTW enrollment and student achievement on state standardized tests of math and science. Results While students gained in math and science achievement overall from eighth to tenth grade, students enrolled in PLTW foundation courses showed significantly smaller math assessment gains than those in a matched group that did not enroll, and no measurable advantages on science assessments, when controlling for prior achievement and teacher experience. The findings do not support the enriched integration hypothesis. Conclusions Engineering education programs like PLTW face both challenges and opportunities to effectively integrate academic content as they strive to prepare students for college engineering programs and careers.