A Statistical Method for SVBRDF Approximation from Video Sequences in General Lighting Conditions

We present a statistical method for the estimation of the Spatially Varying Bidirectional Reflectance Distribution Function (SVBRDF) of an object with complex geometry, starting from video sequences acquired with fixed but general lighting conditions. The aim of this work is to define a method that simplifies the acquisition phase of the object surface appearance and allows to reconstruct an approximated SVBRDF. The final output is suitable to be used with a 3D model of the object to obtain accurate and photo‐realistic renderings. The method is composed by three steps: the approximation of the environment map of the acquisition scene, using the same object as a probe; the estimation of the diffuse color of the object; the estimation of the specular components of the main materials of the object, by using a Phong model. All the steps are based on statistical analysis of the color samples projected by the video sequences on the surface of the object. Although the method presents some limitations, the trade‐off between the easiness of acquisition and the obtained results makes it useful for practical applications.     

Chromium electrodeposition from Cr(III) aqueous solutions

The aim of this work is to study an alternative plating process to obtain chromium coatings through electrodeposition from baths containing trivalent chromium, as aqueous solutions of Cr (III) are significantly less dangerous, in terms of human health and environmental impact, as compared to the traditional Cr (VI) baths employed for this purpose. In order to overcome problems regarding the reduction of Cr (III) in aqueous solution, two approaches were followed: i) the possibility of co-depositing chromium along with a second metal, which could help the process of discharge of Cr³⁺ on the substrate; ii) the use of a specific ligand for the Cr³⁺ ion, which can generate easily reducible complexes at the metal-solution interphase. Both approaches led to interesting results: in particular, the co-deposition enabled us to obtain NiCr alloy with a high percentage of chromium, and the deposition using specific complexing agents allowed optimal bath compositions to be developed both for decorative and hard chromium plating.     

Shear tests of carbon fiber plates bonded to concrete with control of snap-back

In the present paper the problem of brittle debonding between carbon-fiber plates (FRP) and concrete was studied by means of single lap shear tests. Driving the test by controlling the displacement of the free edge of the plate made it possible to describe the pull-out curve up to complete debonding, including the snap-back branch. This permitted to observe that, in the present tests, failure mode and brittleness strongly depend upon the bond length. In particular, specimens with long bond length display a snap-back in the pull-out curve, whereas specimens with short bond length display a softening. Besides, debonding occurs with a transition from mode II to a mixed mode fracture as the bond length decreases, showing different failure mechanisms and a remarkable reduction of the dissipated fracture energy. Moreover, the measured bond-slip relationships show a reduction of the bond strength close to the free edge of the plate that is caused by peeling stresses. Finally, results of the experimental tests are compared with finite element simulations with standard bond-slip laws.     

A prototype of a fuel cell PEM emulator based on a buck converter

After a brief introduction about fuel cell systems, and their modelling, this paper proposes a possible solution to emulate a proton exchange membrane fuel cell (PEM-FC) system by using a DC–DC buck converter. The fuel cell system, including all its auxiliaries and related control systems, is emulated by a buck converter realized experimentally and controlled in the DSPACE environment. The realization of the buck converter allows the behaviour of any fuel cells to be easily emulated since only the modification of the control law of the switch is necessary. The proposed emulator can be applied easily to other fuel cell systems if the polarization curve has the same current rate and maximum power. In this way it is possible to utilize the converter and perform the necessary tests to optimize a fuel cell system by avoiding the waste of hydrogen and the purchase of cells as well as any cell damage. With regard to current other types of emulators, the one presented here has the following characteristics: (1) all the auxiliaries of the system have been considered, each including its own control system, as in a real FCS, (2) the converter is a classical buck converter with a free-wheeling diode and is designed to have a high bandwidth and to be practically always in conduction mode (discontinuous mode appears only at very low currents) (3) the voltage control is made by a space-state controller, able to fix properly the closed loop poles of the system, thus guaranteeing the desired bandwidth of the control system and (4) it can be used in laboratory as a stand-alone low-cost system for design and experimental purposes.     

Reliability allocation methods: A systematic literature review

The choice of a reliability allocation method is not always easy or straightforward, since it depends on several factors. Some factors are directly related to the characteristics of the analyzed system, such as the level of complexity or the reliability configuration; on the other hand, additional aspects constitute boundary conditions, such as budget or experimentation time. In this scenario, the purpose of the present research is to present a systematic literature review on reliability allocation, proposing a guideline to choose the optimal allocation method in respect to the desired application, available resources, and required accuracy. The proposed review analyzes allocation methods in literature, determining main features and area of application. Motivated by a lack of a comprehensive methods summarization present in literature, our research goal is to assist practitioners in choosing a well-suited method and to provide an overview, to support academics in conducting new research in this area. The results of the performed analysis are synthetized according to several criteria. The results are summarized and categorized in different clusters for each individuated application field. The proposed summarization design allows an easy and rapid consultation.     

The transformed gamma process for degradation phenomena in presence of unexplained forms of unit‐to‐unit variability

The transformed gamma process is a suitable model for degradation phenomena where damages accumulate gradually over time in a sequence of tiny increments. Attractiveness of the transformed gamma process mainly lies in the fact that it provides a relatively easy way for dealing with phenomena in which the degradation increments over disjoint time intervals are not independent. The transformed gamma process is also a very flexible model. In fact, it is indexed by 2 functions, the “age function” and the “state function,” whose mathematical form can be chosen ad hoc for modeling the dependence of the future degradation increment of a unit on its current age and state, respectively. In this paper, the transformed gamma process is adopted to describe the degradation paths of degrading units in the presence of an unexplained form of unit‐to‐unit variability. The degradation path of each unit is described via a transformed gamma process. Heterogeneity among paths of different units is accounted for by assuming that the scale parameters of the age and state functions vary randomly from unit to unit. Under these assumptions, a quite mathematically tractable model is obtained. The main properties of the proposed model are discussed, and inferential procedures based on the maximum likelihood criterion are implemented. A simple test is presented to check the goodness of fit of the proposed model. Three applicative examples, based on real degradation data, are developed.     

Arsenic leaching from a gold bearing enargite flotation concentrate

The high arsenic content of the flotation concentrate obtained from a gold-bearing enargite ore for pyrometallurgical processing strongly diminishes its market value. An investigation has been carried out for selectively leaching arsenic from enargite–luzonite minerals using alkaline Na₂S solutions. By suitably adjusting the main reaction conditions almost 98% arsenic was leached, as well as part of the gold, particularly with high Na₂S concentrations. Copper was not lost from the solid phase in which the enargite is converted into a new species with the chemical formula Cu_1.5S.     

Supporting a distributed execution of clinical guidelines

Clinical guidelines (GL) play an important role in medical practice: the one of optimizing the quality of patient care on the basis of evidence based medicine. In order to achieve this goal, the interaction between different agents, who cooperate in the execution of the same GL, is a crucial issue. As a matter of fact, in many cases (e.g. in chronic disorders) the GL execution requires that patient treatment is not performed/completed in the hospital, but is continued in different contexts (e.g. at home, or in the general practitioner's ambulatory), under the responsibility of different agents. In this situation, the correct interaction and communication between the agents themselves is critical for the quality of care, and human resources coordination is a key issue to be addressed by the managers of the involved healthcare services. In this paper we describe how GLARE (Guideline Acquisition, Representation, and Execution), a computerized GL management system, has been extended in order to support such a need. In particular, we have provided: (i) an extension to GL actions representation languages, (ii) proper scheduling and (iii) querying services. By means of these enhancements we aimed at guaranteeing (1) treatment continuity and (2) responsibility assignment support in the various steps of a coordinated and distributed patient care process. We illustrate our approach by means of a practical case study.     

Effect of low frequency,high power pool ultrasonics on viscosity of fluid food: Modeling and experimental validation

Ultrasound induced changes of certain physical and chemical properties of molecules are nowadays exploited at industrial level for food processing and preservation purposes. Deeper knowledge on the mechanisms influencing these changes would contribute to extend implementations of ultrasound to steer structure and functionality of food molecules.