Noise contribution of the body resistance in partially-depleted SOIMOSFETs

An additional noise component is observed in the noise spectrum of transistors in a partially-depleted (PD) medium-thickness SOI-CMOS technology. We identify the origin of this additional noise in the noisy resistance of the body film. This resistance, coupled to the gate capacitance, forms an RC filter and generates the hump-shape of the additional noise component. Several experimental observations that support this model are presented     

Activation of alphav beta3 integrin on human osteoclast-like cells stimulates adhesion and migration in response to osteopontin

Integrins mediate cell adhesion and can induce different cellular responses, including changes in intracellular pH, changes and oscillation in intracellular free calcium, and protein phosphorylation on tyrosine. During bone resorption, the integrin alphav beta3 regulates adhesion of osteoclasts to bone extracellular matrix proteins, such us osteopontin (Opn). Adhesion via alphav beta3 is followed by osteoclast polarization onto the bone surface and by the onset of bone resorption. To characterize these events at the molecular level, we investigated the state of activation of alphav beta3 on the human osteoclast-like cell line GCT23 using the monoclonal antibody AP5 which binds to and can induce, under low calcium conditions, activated alphav beta3. By flow cytometry, approximately 50% of alphav beta3 on the surface of the osteoclast-like cell line GCT23 was reactive with AP5 and was therefore in the activated state. Incubation with AP5 in the presence of low calcium concentrations increased activated alphav beta3 to 90-100%. Activation of alphav beta3 increased the efficiency of GCT23 adhesion to Opn by 2-fold. Furthermore, haptotactic migration on Opn was also enhanced about 40% compared to control. We propose that changes in the activation state of alphav beta3 may be a regulation point for osteoclasts during bone resorption.     

Demonstration of thermal poling in holey fibres

A second-order nonlinearity is induced for the first time in a holey fibre by thermal poling. Non-phase matched second harmonic generation with a ~10^-8/W conversion efficiency is observed and the electro-optic coefficient is measured to be ~0.02 pm/V     

Innovative travel time model for dual-shuttle automated storage/retrieval systems

In modern production and distribution systems, the automated storage/retrieval systems (AS/RS), high-storage level systems that reduce labor cost, required floor space and error rate, while increasing product availability, have been widely used since the 1950s. Due to the high-investment costs involved in the development of high-efficient and high-flexible automated storage systems, performance estimation of the systems is both practically and theoretically important. The authors suggest a new method to estimate the travel time of a recently emerging version of AS/RSs, the multi-shuttle systems. The proposal is based on an industrial standard established by the Federation Européenne de la Manutention (F.E.M.). In order to estimate travel times, the authors conduct a Monte Carlo simulation to determine coordinates of two additional representative points which are not given by F.E.M. Then they conduct a new Monte Carlo simulation to compare the results obtained by the method they proposed with those of previous methods and models developed in scientific literature based on Bozer and White formulations. Several real industrial applications demonstrate the validity of proposed method.     

Design configuration for a mixed-model assembly system in case of low product demand

In order to accompany the increasing variety of costumers’ demands, manufacturers tend to produce different models of the same product on an assembly line by introducing group assembly (GA) design concepts that improve the flexibility of assembly systems. Generally, when the demand for a set of similar products is relatively low and the set-up time is significant, the beneficial effects of the task repeatability of the straight line configuration are difficult to achieve. As a consequence, the fixed-point assembly philosophy is often preferred. This paper addresses the application of a mixed-model assembly balancing problem to an assembly-to-order environment in the case of low production rates and large number of tasks. The aim of this work is to propose an alternative design procedure for the balancing of semi-automated and mixed-model assembly systems under low product demand effects by the application of multi-turn circular transfers, such as a multi-stations rotating table. This layout configuration permits a job enlargement for human operators and, at the same time, provides an increment in task repeatability through the work-pieces assembling by increasing the number of the turns of the transfer. Finally, the developed heuristic procedure is tested on a simple rotating table assembly cell, a partial representation of a complete assembly system of domestic air compressors.     

Balancing–sequencing procedure for a mixed model assembly system in case of finite buffer capacity

In the last decades, the necessity to make production more versatile and flexible has forced assembly line production systems to change from fixed assembly lines to mixed model assembly lines, where the output products are variations of the same base product and only differ in specific customizable attributes. Such assembly lines allow reduced setup time, since products can be jointly manufactured in intermixed sequences (Boysen, Flieder, Scholl. Jena Research Papers in Business and Economics, Friedrich-Schiller-Universitat Jena, 1;1–11, 2007a; Boysen, Flieder, Scholl. Jena Research Papers in Business and Economics, Friedrich-Schiller-Universitat Jena, 2;1–33, 2007b). Unfortunately, the installation of customization options typically leads to variations in process times, and when the cycle is exceeded within a certain station, an overload is created, forcing other stations to wait and idle. Normally, process time variation in an un-paced line are absorbed by buffers, but in some industrial application the buffer dimensions are critical not only for the reduction of work in progress but also in reducing other constrains (space, technology, model dimensions, etc.). The problem of balancing mixed model assembly lines (MALBP), in the long term, and that of sequencing mixed model assembly lines (MMS), in the short term (Merengo, Nava, Pozetti. Int J Prod Res 37:2835–2860, 1999), are the two major problems to solve. The object of this paper is to illustrate an innovative balancing–sequencing step-by-step procedure that aims to optimize the assembly line performance and at the same time contain the buffer dimensions in function of different market demand and production mix. The model is validated using a simulation software and an industrial application is presented.     

Energy saving in case of intermittent production by retrofitting service plant systems through inverter technology: a feasibility study

Many production machines have high energy consumption due to the large number of electrical motors used to rotate equipment, such as tools, fans and pumps. Moreover, in different industrial sectors production is not continuous but intermittent, where working times alternate with idle times. During idle times continuous switch off is not always possible due to technical limitations, and if it is possible, it can cause higher energy consumption due to peak current at the start-up of the electrical motors. The purpose of this paper is to introduce the possibility of managing intermittent production using inverter technology. The inverter provides power control by managing the frequency and voltage of the power supplied to the alternating current motors. The study analyses the potential energy consumption reduction as a function of the production parameters (number of daily stops, average working time, etc.) and develops a feasibility analysis, its related investment cost and its potential energy consumption reduction. As a result, the proposed feasibility study defines the set of production parameters and the types of equipment for which this technology is suitable, bringing rapid investment payback. The proposed feasibility analysis is validated by an industrial case study related to a tannery spray plant.     

Broad-band second-harmonic generation in holey optical fibers

Holey fibers are shown to have an ideal geometry for efficient parametric processes due to their tailorable modal properties. These fibers can have the additional advantage of single-mode operation at all the interacting wavelengths. We demonstrate theoretically that by appropriate choice of holey fiber geometry, these fibers can be up to four orders of magnitude more efficient for second harmonic generation than conventional poled fibers     

New ADC with piecewise linear characteristic: casestudy-implementation of a smart humidity sensor

In this paper, the architecture of a new analog-to-digital converter (ADC) with a piecewise linear characteristic (PLADC) is proposed. In this device, some discrete points of the characteristic can be modified to fit a requested profile. This converter facility can be utilized to gain remarkable advantages in a wide variety of applications, such as the implementation of a sensor linearization technique. In the paper the internal architecture of a two-stage 11-b flash PLADC prototype is briefly described. A representative demonstrative application, namely, the implementation of a linear digital humidity sensor, is discussed showing the effectiveness and usefulness of this device. The problem of the characterization of this converter is also discussed, reporting some remarks about the implemented solutions