Modeling and compensation of cutting-forces generated during the EDM process for ultra high-precision robots

This work deals with the calibration of industrial robots operating at sub-micrometric precision. We demonstrate that the cutting-forces generated by the robot manufacturing process cause a significant deformation of the robot geometry, lo- wering its absolute accuracy. Then, we propose a way of studying and modeling such deformations, in order to compen- sate them during the robot usage. We have taken the micro electro-discharge machining process on the robot Agietron micro-nano as a case study and we have used an ultra high-precision measuring system to evaluate the deformations due to cutting-forces. Finally, we have built a mathematical model of the robot physical behavior and we have implemented it in the robot controller, in order to compensate the deformations in real-time

DLC Thin Films and Carbon Nanocomposite Growth by Thermionic Vacuum Arc (TVA) Technology

The aim of this chapter is to report the results on synthesis DLC thin films and carbon nanocomposites by the versatile nanofabrication method based on plasma entitled thermionic vacuum Arc (TVA). TVA technology is based on the localized ignition of the arc plasma in vacuum conditions. Among thin film coating methods by vacuum deposition techniques with high purity, low roughness, and good adhesion on the substrates, TVA is one of the major suitable methods to become a powerful coating technology. Two or three different TVA discharges can be ignited simultaneously in the same chamber for multi-material processing using TVA and separate power supplies. These TVA discharges are localized and do not interfere with each other. Simultaneous two or three TVA discharges were already used for the production of alloy/composite of various materials. This is due to the high versatility concerning the configuration of experimental arrangements, taking into account the number of electron guns, symmetry of the electrodes, relative position of the anode versus cathode, and also the huge opportunity to combine the materials to be deposited: bi- and multi-layers, nanocomposites, or alloys in order to have specific applications. This chapter presents the comparative results concerning the surface-free energy information processing, the reflective index, the hardness, and the morphology to provide a coherent description of the diamond-like carbon films and carbon nanocomposites synthesized by thermionic vacuum arc (TVA) and related configurations where Me = Ag, Al, Cu, Ni, and Ti: binary composites (C-Me, C-Si) and ternary composites (C+Si+Me). The results include reports on the distribution in size, surface, geometry, and dispersion of the nanosized constituents, tailoring and understanding the role of interfaces between structurally or chemically dissimilar phases on bulk properties, as well as the study of physical properties of nanocomposites (structural, chemical, mechanical, tribological). The results presented here could have a great impact on the development of advanced materials and many manufacturing industries, as well as expanding the technologically important field of interface science where the control of the film-substrate interface would be critical

Direct observation of growth and collapse of a Bose-Einstein condensate with attractive interactions

The dynamical behavior of Bose-Einstein condensation (BEC) in a gas with attractive interactions is striking. Quantum theory predicts that BEC of a spatially homogeneous gas with attractive interactions is precluded by a conventional phase transition into either a liquid or solid. When confined to a trap, however, such a condensate can form provided that its occupation number does not exceed a limiting value. The stability limit is determined by a balance between self-attraction and a repulsion arising from position-momentum uncertainty under conditions of spatial confinement. Near the stability limit, self-attraction can overwhelm the repulsion, causing the condensate to collapse. Growth of the condensate, therefore, is punctuated by intermittent collapses, which are triggered either by macroscopic quantum tunneling or thermal fluctuation. Previous observation of growth and collapse has been hampered by the stochastic nature of these mechanisms. Here we reduce the stochasticity by controlling the initial number of condensate atoms using a two-photon transition to a diatomic molecular state. This enables us to obtain the first direct observation of the growth of a condensate with attractive interactions and its subsequent collapse.Comment: 10 PDF pages, 5 figures (2 color), 19 references, to appear in Nature Dec. 7 200

Hybrid density functional studies of bulk actinide oxides

Actinide materials are systems rich in interesting physics, while playing an important role in environmental preservation, and a good comprehension of their electronic structure is therefore of particular importance. A first-principles computational methodology is proposed in this work, affording accurate density functional theory studies in such strongly-correlated crystalline systems. The main ingredient behind the success of this approach is the use of hybrid density functionals, which provide good agreement with known experimental data for the optimum structural and electronic properties of the actinide oxides considered in this study. The predictive capabilities of the method help understand certain unusual properties and phenomena associated with these compounds, from puzzling experimental findings to the relative stability of heavy actinide oxides. Plutonium dioxide is taken as a case study in this work and detailed structural investigations are considered for this compound, such as the effects of non-stoichiometry and of various lattice distortions. The interstitial oxygen in PuO2.25 for example is found to be singly charged, consistent with experimental observations and contrary to the O2- previously proposed theoretically. A tetragonal distortion of the PuO2 lattice, with a very small orthorhombic component, is energetically favorable in our description at zero temperature. Such lattice deformation anticipates the experimentally observed orthorhombic phase, to which many actinide dioxides transform at high pressures. We also confirm that non-hydrostatic effects could be responsible for the intriguing value of the only measurement to date of the bulk modulus of PuO2. Unexpected f orbital populations are predicted in heavy actinide dioxides, and they could elucidate certain perplexing structural measurements made on these compounds. These occupancies point to an early-occurring half-filled shell effect, and can also explain the lack of experimental evidence for the heavier actinide dioxides. These findings suggest that accepted models of electronic structure for certain open-shell compounds are not always warranted, and that their theoretical descriptions should be revised accordingly

Spokeheel: Autonomous robot with high mobility and magnetic adhesion.

This paper describes the conception of a mobile robot for industrial inspection of ferromagnetic environments

Intensity Dependence of Photoassociation in a Quantum Degenerate Atomic Gas

We have measured the intensity dependent rate and frequency shift of a photoassociation transition in a quantum degenerate gas of Li7. The rate increases linearly with photoassociation laser intensity for low intensities, whereas saturation is observed at higher intensities. The measured rates and shifts agree reasonably well with theory within the estimated systematic uncertainties. Several theoretically predicted saturation mechanisms are discussed, but a theory in which saturation arises because of quantum mechanical unitarity agrees well with the data

The Use of Wound Infiltration for Postoperative Pain Management after Breast Cancer Surgery: A Randomized Clinical Study

(1) Background: The present study aims to evaluate the reduction of postoperative pain in breast surgery using a series of local analgesics, which were infiltrated into the wound; (2) Methods: Envelopes containing allocation were prepared prior to the study. The patients involved were randomly assigned to the groups of local anesthesia infiltration (Group A) or normal pain management with intravenous analgesics (Group B). The random allocation sequence was generated using computer-generated random numbers. The normally distributed continuous data were expressed as the means (SD) and were assessed using the analysis of variance (ANOVA), independent-sample t-test, or paired t-test; (3) Results: The development of the postoperative pain stages was recorded using the VAS score. Therefore, for Group A, the following results were obtained: the VAS at 6 h postoperatively showed an average value of 0.63 and a maximum value of 3. The results for Group B were the following: the VAS score at 6 h postoperatively showed an average value of 4.92, a maximum of 8, and a minimum of 2; (4) Conclusions: We can confirm that there are favorable statistical indicators regarding the postoperative pain management process during the first 24–38 h after a surgical intervention for breast cancer using local infiltration of anesthetics

The Value of Tumor Infiltrating Lymphocytes (TIL) for Predicting the Response to Neoadjuvant Chemotherapy (NAC) in Breast Cancer according to the Molecular Subtypes

Introduction: The antitumor host immune response is an important factor in breast cancer, but its role is not fully established. The role of tumor infiltrating lymphocytes (TIL) as an immunological biomarker in breast cancer has been significantly explored in recent years. The number of patients treated with neoadjuvant chemotherapy (NAC) has increased and the identification of a biomarker to predict the probability of pCR (pathological complete response) is a high priority. Materials and methods: We evaluated 334 cases of BC treated with NAC followed by surgical resection from 2020–2022 at the Ist Clinic of Oncological Surgery, Oncological Institute “Prof Dr I Chiricuta” Cluj Napoca. Of the above, 122 cases were available for histological evaluation both in pre-NAC biopsy and post-NAC resection tissue. Evaluation of biopsy fragments and resection parts were performed using hematoxylin eosin (H&E). The TIL evaluation took place according to the recommendations of the International TIL Working Group (ITILWG). Results: There was a strong association between elevated levels of pre-NAC TIL. At the same time, there is a statistically significant correlation between stromal TIL and tumor grade, the number of lymph node metastases, the molecular subtype and the number of mitoses (p p < 0.005). We also demonstrated that high pre-NAC STIL represents a strong predictive marker for pCR. Conclusion: This study reveals the role of TIL as a predictive biomarker in breast cancer not only for the well-established TNBC (triple negative breast cancer) and HER2+ (Her2 overexpressed) subtypes but also in Luminal A and B molecular subtypes. In this scenario, the evaluation of sTIL as a novel predictive and therapy-predicting factor should become a routinely performed analysis that could guide clinicians when choosing the most appropriate therapy