Temperature Modulation Measurements of the Thermal Properties of Nanosystems at Low Temperatures

We report on the dynamic measurements of thermal properties of nanosystems at very low temperatures. These techniques are based on the modulation of the temperature and hence leads to highly sensitive measurements. We will discuss the intrinsic limitations of these methods when the thermal properties of nano-objects are studied at very low temperatures, much below 1 K. Firstly, we will present thermal conductance measurements using the 3ω method. This technique is limited at low temperatures due to the significant increase of the mean free path. Secondly, heat capacity measurements using ac calorimetry are outlined, and again restrictions occur due to the continuous temperature gradient inherent to that technique. Propositions are made in order to overcome these limitations.     

Retention of Free Liquids in Landfills Undergoing Vertical Expansion

This paper presents the results of an evaluation of the potential release of liquids stored within a waste mass undergoing compression due to a landfill vertical expansion. The mechanism of free liquid generation is initially evaluated and data interpretation methods are developed to estimate the maximum allowable waste thickness that a landfill could reach without releasing liquids stored within the waste. The proposed conceptual framework of free liquid generation is used to evaluate the environmental implications of the vertical expansion of an unlined case history landfill located in southern California. The moisture content of waste in southern California landfills is generally below field capacity. However, if the waste is compressed, its available moisture-holding capacity will decrease and its moisture content may eventually reach field capacity. Additional compression beyond this point will squeeze liquid from the waste. Laboratory testing and field characterization programs were undertaken to evaluate the field capacity, the in-situ moisture distribution, and the unit weight profiles of the waste in the case history landfill. These experimental data were used to evaluate the ability of the landfill to continue to retain moisture after continued waste placement. The evaluation indicated that the moisture content of the waste will not reach its field capacity for the proposed final grading of the case history landfill and, therefore, that the liquids should remain within the waste mass after the vertical expansion.     

The structure of cyclin H: common mode of kinase activation and specific features

The crystal structure of human cyclin H refined at 2.6 A resolution is compared with that of cyclin A. The core of the molecule consists of two repeats containing five helices each and forming the canonical cyclin fold also observed in TFIIB. One hundred and thirty-two out of the 217 C alpha atoms from the cyclin fold can be superposed with a root-mean-square difference of 1.8 A. The structural homology is even higher for the residues at the interface with the kinase, which is of functional significance, as shown by our observation that cyclin H binds to cyclin-dependent kinase 2 (cdk2) and that cyclin A is able to activate cdk7 in the presence of MAT1. Based on this superposition, a new signature sequence for cyclins was found. The specificity of the cyclin H molecule is provided mainly by two long helices which extend the cyclin fold at its N- and C-termini and pack together against the first repeat on the side opposite to the kinase. Deletion mutants show that the terminal helices are required for a functionally active cyclin H.     

Finite-range topical functions and uniformly topical functions

We introduce a remarkable subclass of the class of topical functions, the class of uniformly topical functions, whose dynamical behaviour is investigated. Every uniformly topical endofunction has a spectral vector, related to some special fixed points (possibly at infinity), about which we establish various properties. In the stochastic case, we prove a multiplicative ergodic theorem, asserting that the stochastic spectral vector exists in all cases.     

Thermal stability and crystallisation of a Zr55Cu30Al10Ni5 bulk metallic glass studied by in situ ultrasonic echography

An original in situ ultrasonic echography technique was used to study the thermal stability and crystallisation of a Zr₅₅Cu₃₀Al₁₀Ni₅ bulk metallic glass between RT and 630 °C. Changes in Young's modulus with temperature were reported allowing to study the supercooled-liquid state and the crystallisation process. Investigations of viscoelastic properties gave information on the correlation factor (hierarchically correlated motion theory) and three distinct crystallisation stages were observed. Their kinetics were studied using Voigt's and Reuss' approximations for a two-phase material and comparisons with the Johnson–Mehl–Avrami–Kolmogorov theory allowed us to consider a mixed surface/internal nucleation for the first stage and a surface nucleation for the two last stages.     

Comparison of ATM switching architectures

Clear examination of work currently done within CCITT indicates the importance of a broadband telecommunication network. As this network should be capable of integrating all services in an efficient way—in order to reduce cost—the asynchronous transfer mode (ATM) was selected by CCITT as the target transfer mode for implementing the broadband integrated services digital network (BISDN). This selection implies that the switching nodes in the BISDN network are capable of supporting this high-speed packet and connection-orientated technique. Within the literature different switching node architectures based upon ATM have been proposed. All of these architectures should meet the high-speed and high-throughput requirements so as to cope with the delay and jitter performance objectives. In a first step this paper describes alternative switching techniques for the basic building block (switching element) of a switching node. A common model architecture of the switching element is drafted. A classification of switching elements described in the literature is derived and the influence on the complexity and performance is weighted. In a second step the switching node architecture is further elaborated according to the control and flexibility requirements. Core (switching) and edge (switching related) functions are listed, and possible functional partitionings are discussed. Finally, these ATM switching architectures are compared according to a background frame consisting of several straightforward comparison points such as the buffering strategy, the internal routeing method, the switching overhead, the connection-orientated or connectionless operation, etc.     

A study of assessors'' performance using graphical methods

The performance of a sensory panel is studied through analysis of variance and in particular the assessors × products interaction. A graphic can illustrate the partitioning of the interaction by a sum of distances between the assessors. The decomposition of the sum of the product effect plus the interaction allows a vector representation of the assessors. These vectors are classified with an original method in order to point out homogeneous sub-panels. The new classification allows aggregation of groups only when all the correlations between assessors are greater than a threshold.     

The complete sequence of the 8.2 kb segment left of MAT on chromosome III reveals five ORFs, including a gene for a yeast ribokinase

We report here the DNA sequence of a segment of chromosome III extending over 8.2 kb. The sequence was determined using the random clone strategy followed by oligonucleotide-directed sequencing. The segment contains five long open reading frames, YCR521, 522, 523, 524 and 526, with only short distances between them. YCR523 (333 codons) encodes a ribokinase, a new function for yeast. YCR526 originates inside the MAT cassette, which is in continuity with the present segment, and extends over 358 codons outside of MAT. YCR524 (923 codons) codes for a putative membrane protein. YCR521, 522 and 524, have each been disrupted by insertion of a URA3 cassette and are non-essential genes. An active ARS element is located within YCR523 or its vicinity.