Scalable model for predicting the effect of negative bias temperature instability for reliable design

The authors present a predictive model for the negative bias temperature instability (NBTI) of PMOS under both short term and long term operation. On the basis of the reaction-diffusion mechanism, this model accurately captures the dependence of NBTI on the oxide thickness (t _ox), the diffusing species (H or H ₂) and other key transistor and design parameters. In addition, a closed form expression for the threshold voltage change (DeltaV_th) under multiple cycle dynamic operation is derived. Model accuracy and efficiency were verified with 180, 130 and 90 nm silicon data. The impact of NBTI on the delay degradation of a ring oscillator and the various metrics of the SRAM such as its data retention voltage, read and hold margins, as well as read and write delay, is also investigated.     

Host country cultural influences on foreign direct investment

Abstract and Key Results

Effects of the inclination angle on natural convection heat transfer and entropy generation in a square porous enclosure

ABSTRACT

In this paper, we analyze numerically the effects of the inclination angle on natural convection heat transfer and entropy generation characteristics in a two-dimensional square enclosure saturated with a porous medium. There is a significant alteration in Nusselt number with the orientation of the enclosure at higher values of Rayleigh number. It reveals that the variation of entropy generation rate with the inclination angle is significant for higher values of Darcy number. The dominant source of irreversibility is due to heat transfer at low values of Darcy number, whereas entropy generation due to fluid flow dominates over that due to heat transfer for larger values of Darcy number.     

Synergetic effects of radiolytically degraded PTFE microparticles and organoclay in PTFE-reinforced ethylene vinyl acetate composites

This article reports exceptional synergistic effects observed in organic–inorganic dual filler containing ethylene vinyl acetate (EVA) composites. Polytetrafluoroethylene microparticles (PTFEMP) were produced by mechanically grinding radiolytically degraded PTFE; composites of EVA containing PTFEMP and organoclay were prepared in different proportions by melt compounding and their mechanical, melt flow, morphological and crystallographic characteristics were examined. Mechanical properties of ternary composites demonstrated high synergy between fillers, leading to manifold increase in the modulus of dual filler filled composites in comparison to single filler systems. Nielsen model fitted well with EVA/PTFEMP system; however it predicted remarkably low values for EVA/PTFEMP/organoclay system, confirming exceptional synergy between two fillers. Melt viscosity of EVA increased substantially on the addition of either of the fillers. X-ray diffraction studies revealed around 10% intergallery expansion in organoclay, in the composites having high loading of PTFEMP; though the crystallinity of EVA did not change.     

Characteristics of a Work Organization from a Lean Perspective

Abstract:

Implementation of lean practices results in significant changes in an organization. Current research in lean production primarily focuses on examining relationships between the implementation of lean production (LP) and the performance of the organization; however, there is a need to assess the implications of large-scale changes such as lean production on work design characteristics and employee outcomes. The purpose of this article is to study the impact of lean production on work design characteristics, such as autonomy, task identity and skill variety, and employee outcomes. This article proposes a conceptual framework that indicates key LP practices and their influences on work characteristics and employee outcomes.

Current research in LP identifies transformations in lean models inspired by sociotechnical principles. This article presents a comprehensive literature review of an evaluation of LP based on sociotechnical design principles. This evaluation contributes toward developing an insight for the proposed framework of the work design characteristics in a lean environment. Finally, a causal loop diagram is used to derive theoretical implications of the conceptual framework proposed.     

Periodic heat transfer in sunlit moist ground: Evaluation of rates of moisture evaporation

This paper present an analysis of the periodic heat transfer in moist ground exposed to periodic solar radiation and atmospheric temperature. This analysis yields a novel method for the evaluation of daily/hourly moisture evaporation from the ground. It is found that in harsh climates a significant amount of moisture ( 4 lb/ft²/day) is evaporated from sunlit ground near the sea and in windy regions. The rate of moisture evaporation decreases with relative humidity and increases with wind speed.     

Thinning analysis for hot forming of single-piece hemispherical dish end using finite element simulation and its empirical modeling

Hot forming is an important forming method for production of small and medium sized single-piece pressure vessel dish ends. Thinning of the blank material with increased degree of forming is quite obvious. Present work shows finite element (FE) analysis of hot forming of single-piece hemispherical dish end (SPHDE) for predicting maximum thinning of blank during forming. Thinning analysis is performed for SPHDE of two different ferrous material grades SA-387 Gr22 and SA-516 as per ASME, Section II, Part A (2004). Percentage thinning results of FE analysis are verified with the practical material thinning data. Based on the thinning analysis, empirical relation for calculation of percentage thinning as a function of different dish ends′ geometry parameters is proposed. Empirically predicted percentage thinning is observed to be in good agreement with practical and FE simulation results. Thinning results obtained based on proposed FE simulation and empirical model can be helpful to design engineer in selecting thickness of developed blank considering thinning allowance for hot forming of SPHDE. Thinning analysis data can be used for optimizing the dish end geometrical parameters for minimum thinning during forming.     

Emission measurements from a crude oil tanker at sea

This work presents an all-inclusive set of regulated and nonregulated emission factors for the main propulsion engine (ME), auxiliary engine (AE) and an auxiliary boiler on a Suezmax class tanker while operating at sea. The data include criteria pollutants (carbon monoxide, nitrogen oxides, sulfur oxides, and particulate matter), a greenhouse gas (carbon dioxide), the principal speciated hydrocarbons needed for human health risk assessments, and a detailed analysis of the PM into its primary constituents (ions, elements, organic, and elemental carbon). Measurements followed ISO 8178-1 methods with modifications described in the paper. The vessel burned two fuels: a heavy fuel oil in the ME and boiler and a distillate fuel in the AE. The weighted NO(x) emissions for the ME and AE are 19.87 +/- 0.95 and 13.57 +/- 0.31 g/kWh, respectively. The weighted PM mass emissions factor is 1.60 +/- 0.08 g/kWh for the ME and 0.141 +/- 0.005 g/kWh for the AE, with the sulfate content of the PM being the root cause for the difference. For the ME, sulfate with associated water is about 75% of total PM mass, and the organic carbon ranges from 15 to 25% of the PM mass. A deeper analysis showed that the conversion of fuel sulfur to sulfate in the ME ranged from 1.4to 5%. This article also provides emission factors for selected polycyclic aromatic hydrocarbons, heavy alkanes, carbonyls, light hydrocarbon species, metals, and ions for the ME, AE, and the boiler.     

A facile route for the preparation of silica foams using rice husk ash

This work aims to synthesize silica foam with around 75 vol. % open porosity without using any additive or pore forming agents, in order to prevent the generation of greenhouse gases during pore formation in the silica matrix. Waste rice husk ash (RHA) derived silica is used as a silica source, which is extracted through the alkali extraction synthesis route. Several physical characterizations such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), differential thermal-thermogravimetric (DTA-TGA) and FTIR analysis have been done for RHA extracted silica. Silica foam specimens are fabricated through control compaction pressure and at low foaming temperature. Samples which are fired at 550°C for 30 minutes exhibit both a adequate apparent porosity (AP; ~75.82%) and significant compressive strength (~1.54 MPa). It can also be observed that the porosity and strength values are changed with the variation in compaction pressure and foaming temperature.