A 2.2 W, 80 MHz superscalar RISC microprocessor

A 28 mW/MHz at 80 MHz structured-custom RISC microprocessor design is described. This 32-b implementation of the PowerPC architecture is fabricated in a 3.3 V, 0.5 μm, 4-level metal CMOS technology, resulting in 1.6 million transistors in a 7.4 mm by 11.5 mm chip size. Dual 8-kilobyte instruction and data caches coupled to a high performance 32/64-b system bus and separate execution units (float, integer, loadstore, and system units) result in peak instruction rates of three instructions per clock cycle. Low-power design techniques are used throughout the entire design, including dynamically powered down execution units. Typical power dissipation is kept under 2.2 W at 80 MHz. Three distinct levels of software-programmable, static, low-power operation-for system power management are offered, resulting in standby power dissipation from 2 mW to 350 mW. CPU to bus clock ratios of 1×, 2×, 3×, and 4× are implemented to allow control of system power while maintaining processor performance. As a result, workstation level performance is packed into a low-power, low-cost design ideal for notebooks and desktop computers     

A fully integrated dual-channel log-domain programmable preamplifier and filter for an implantable cardiac pacemaker

A programmable-gain preamplifier and filter for detection of spontaneous heart activity in an implantable cardiac pacemaker is presented. The system is fully integrated in a standard 0.35-/spl mu/m CMOS technology, including all auxiliary circuits. Two channels are available in order to process both atrial and ventricular signals. CMOS translinear circuits, with particular emphasis on log-domain techniques, have been exploited in order to contain current consumption and to allow correct operation with a reduced supply voltage, due to battery discharging. Indeed, the realized system can operate down to 1.8 V of supply voltage and dissipates at most 1.8 /spl mu/A, granting at least 47 dB of dynamic range (DR) for the atrial chain, which is compatible with advanced digital sensing. Current consumption can be further reduced at the expense of DR if a simpler sensing like peak detection is adopted. All system performance have been verified by measurements results and are compatible with the requirements of cardiac pacemakers. This work, therefore, demonstrates how a proper design approach, exploiting low-power and low-voltage techniques, allows one to optimize performance for the cardiac pacemaker.     

Thixomolded magnesium alloys: Strategic product innovation in automobiles

The research on magnesium alloys for structural lightweight applications is today at an embryonic stage, but these alloys offer great potential. Thixomolding of magnesium alloys for automotive applications is promising since the process can be used to manufacture net-shape parts cost-effectively and with high reliability and repeatability.     

Bond strengths of toluenes, anilines, and phenols: to hammett or not

The Hammett equation correlates the effects of Y on many different chemical properties of YC(6)H(4)ZX families of compounds. One of the most surprising is that the Z-X bond dissociation enthalpy (BDE), a homolytic property, can be correlated for some 4-YC(6)H(4)ZX families with electrophilic substituent constants, sigma(p)(+)(Y), which were largely derived from the rates of the heterolytic S(N)1 solvolyses of para-substituted cumyl chlorides. Although there is no Hammett correlation of the C-X BDEs in 4-YC(6)H(4)CH(2)X (X = H, halide, OPh) families, there are good correlations of N-X BDEs with sigma(p)(+)(Y) in 4-YC(6)H(4)NHX (X = H, CH(3), OH, F) and excellent correlations of O-X BDEs with sigma(p)(+)(Y) in 4-YC(6)H(4)OX (X = H, CH(3), CH(2)Ph) families. The reasons for this varied behavior are discussed.     

Social movement documentary practices: digital storytelling,social media and organizing

ABSTRACT

Scholars and activists have studied social movement media for its potential to challenge dominant narratives, build community relationships and create social change. This paper presents a case study of two short-form documentary projects with Black Lives Matter 5280 and the Service Employees International Union, Local 105 in Denver, Colorado to explore how collaborative media-making projects assist in building local grassroots campaigns of racial and economic justice. The communication strategies as well as the distribution efforts via online social networks and community screenings are discussed in order to analyse how documentaries rely upon personal narratives to animate members and allies’ feelings and then connect them with traditional forms of organizing like community meetings and public demonstrations. The participatory aspects of filmmaking are viewed through democratic theory, which emphasizes the social relations of citizenship and shared communal values over material and cultural resources, rather than visual aesthetics or technical processes.     

The behaviour of consolidated Neapolitan yellow Tuff against salt weathering

Bulletin of Engineering Geology and the Environment - Salt crystallization is a strong weathering agent in porous building materials. The crystallization pressure exerted by salt crystals, growing...     

宽带数字单边带下变频器

数字单边带下变频器是软件无线电中不可缺少的组成部分,也是射电观测中,数据采集设备的重要组成部分,由于该模块紧接高速A/D采样器之后,所以对其运算处理能力有很高的要求.本文提出了实现宽带数字单边带下变频器的一种可行方案——并行处理,可以从根本上解决数字信号处理的瓶颈效应.     

3D Bioprinting of Gelatin–Xanthan Gum Composite Hydrogels for Growth of Human Skin Cells

In recent years, bioprinting has attracted much attention as a potential tool for generating complex 3D biological constructs capable of mimicking the native tissue microenvironment and promoting physiologically relevant cell–cell and cell–matrix interactions. The aim of the present study was to develop a crosslinked 3D printable hydrogel based on biocompatible natural polymers, gelatin and xanthan gum at different percentages to be used both as a scaffold for cell growth and as a wound dressing. The CellInk Inkredible 3D printer was used for the 3D printing of hydrogels, and a glutaraldehyde solution was tested for the crosslinking process. We were able to obtain two kinds of printable hydrogels with different porosity, swelling and degradation time. Subsequently, the printed hydrogels were characterized from the point of view of biocompatibility. Our results showed that gelatin/xanthan-gum bioprinted hydrogels were biocompatible materials, as they allowed both human keratinocyte and fibroblast in vitro growth for 14 days. These two bioprintable hydrogels could be also used as a helpful dressing material.     

Multifunctional TiO2 coatings for Cultural Heritage

Environmental pollution arising from industrial implants and urban factors is constantly increasing, causing aesthetical and durability concerns to urban structures exposed to the atmosphere.