The shape of metallic constrictions of nanoscopic dimensions ~necks! formed using a scanning tunneling microscope is shown to depend on the fabrication procedure. Submitting the neck to repeated plastic deformation cycles makes it possible to obtain long necks or nanowires. Point-contact spectroscopy results show that these long necks are quite crystalline, indicating that the repeated cycles o...

PURPOSE The purpose of this study was to evaluate the mechanical performance of different suture locking mechanisms including: i) interference fit between the anchor and the bone (eg, 4.5 mm PushLock, 5.5 mm SwiveLock), ii) internal locking mechanism within the anchor itself (eg, 5.5 mm SpeedScrew), or iii) a combination of interference fit and internal locking (eg, 4.5 mm MultiFIX P, 5.5 mm Mu...

The mechanical energy exchanges between components of a muscle-tendon complex, i.e. the contractile element (CE) and the series elastic element (SEE), and the environment during stretch-shorten cycles were examined. The efficiency of the storage and release of series elastic energy (SEE efficiency) and the overall mechanical efficiency of the rat gastrocnemius muscle (N = 5) were determined for...

Liquid recirculation is a method of improving evaporator performance by supplying the evaporator with more liquid than is evaporated. The excess liquid, which is generally provided by means of an externally-driven, mechanical pump, eliminates dryout and increases overall heat transfer coefficient in the evaporator. Liquid recirculation is common in large-scale industrial refrigeration systems, ...

In this study, Al/Al2O3 composites with two different particle sizes of 1 µm and 0.3 µm were produced via accumulative roll bonding (ARB). The microstructure evolution, mechanical properties and fracture behavior of the composites were investigated. Results show that higher ARB cycles are required to achieve a uniform distribution of particles in the composite with 0.3 µm particle size. During ...

BACKGROUND Isolation of sperm suitable for ICSI from fresh or frozen-thawed testicular sperm extraction (TESE) can be facilitated by mechanical or enzymatic processing of the samples. METHODS A retrospective multicentre study was initiated to compare these two approaches. Eleven German centres provided data on their TESE cycles performed during the period 1996/1997. Quality of retrieved sperm...

We prove the following results : (a) The Cube-Connected Cycles network of dimension n is a subgraph of the Butterry network of dimension n. (b) The Shuue-Exchange network of dimension n is a subgraph of the DeBruijn network of dimension n.

This study investigated the influence of cycle frequency and workload on muscle coordination and the ensuing relationship with mechanical efficiency and power output of human limb movement. Eleven trained cyclists completed an array of cycle frequency (cadence)-power output conditions while excitation from 10 leg muscles and power output were recorded. Mechanical efficiency was maximized at inc...

Rock instabilities can represent major risks for local populations depending on their geographical location. Even if different mechanisms are known to trigger rockfalls such as precipitation, seismic activity and freezing, many occur during periods when absent. Some recent studies have pointed out the role of thermal cycling in crack initiation or propagation. Here we use data from nearly five ...

The serious health risks posed by bone fractures create a growing need for accurately diagnosing fracture risk. The Reference Point Indentation instrument (RPI) directly measures key mechanical properties in vivo to assess bone fracturability. There is a wealth of information that could be obtained from measuring cryopreserved bone samples with the RPI. Since it is unknown how freezing affects ...