Selection of optimal EDM machining parameters for the given machining surface

Abstract To achieve high removal rate and low electrode wear when roughing by the sinking electrical discharge machining process (EDM), appropriate average surface power density is required in the gap between the workpiece and the electrode, i.e. rough machining parameters have to be tuned to the machining surface. Since machining surface varies with the depth of machining, the rough machining parameters have to be selected on-line to obtain appropriate average surface power density in the gap. The systems for on-line selection of the rough machining parameters of EDM process presented in the literature either have hardly acceptable disadvantages or they are very complex. Thus, a simple solution could be a significant step towards better automation of the EDM rough machining and micro electrical discharge machining (MEDM). In this paper, a system for on-line selection of the machining parameters according to the given machining surface is presented. The selection of the machining parameters is based on the acquisition of only one process attribute, i.e. the percentage of short-circuit discharges, which is significant improvement comparing to known systems

R&D Cooperatives and Market Collusion: A Global Dynamic Approach

We present a continuous-time generalization of the seminal R&D model of d’Aspremont and Jacquemin (American Economic Review, 1988) to examine the trade-off between the benefits of allowing firms to cooperate in R&D and the corresponding increased potential for product market collusion. We consider all trajectories that are candidates for an optimal solution as well as initial marginal cost levels that exceed the choke price. Firms that collude develop further a wider range of initial technologies, pursue innovations more quickly, and are less likely to abandon a technology. Product market collusion could thus yield higher total surplus

The IDENTIFY study: the investigation and detection of urological neoplasia in patients referred with suspected urinary tract cancer - a multicentre observational study

Objective To evaluate the contemporary prevalence of urinary tract cancer (bladder cancer, upper tract urothelial cancer [UTUC] and renal cancer) in patients referred to secondary care with haematuria, adjusted for established patient risk markers and geographical variation. Patients and Methods This was an international multicentre prospective observational study. We included patients aged ≥16 years, referred to secondary care with suspected urinary tract cancer. Patients with a known or previous urological malignancy were excluded. We estimated the prevalence of bladder cancer, UTUC, renal cancer and prostate cancer; stratified by age, type of haematuria, sex, and smoking. We used a multivariable mixed-effects logistic regression to adjust cancer prevalence for age, type of haematuria, sex, smoking, hospitals, and countries. Results Of the 11 059 patients assessed for eligibility, 10 896 were included from 110 hospitals across 26 countries. The overall adjusted cancer prevalence (n = 2257) was 28.2% (95% confidence interval [CI] 22.3–34.1), bladder cancer (n = 1951) 24.7% (95% CI 19.1–30.2), UTUC (n = 128) 1.14% (95% CI 0.77–1.52), renal cancer (n = 107) 1.05% (95% CI 0.80–1.29), and prostate cancer (n = 124) 1.75% (95% CI 1.32–2.18). The odds ratios for patient risk markers in the model for all cancers were: age 1.04 (95% CI 1.03–1.05; P < 0.001), visible haematuria 3.47 (95% CI 2.90–4.15; P < 0.001), male sex 1.30 (95% CI 1.14–1.50; P < 0.001), and smoking 2.70 (95% CI 2.30–3.18; P < 0.001). Conclusions A better understanding of cancer prevalence across an international population is required to inform clinical guidelines. We are the first to report urinary tract cancer prevalence across an international population in patients referred to secondary care, adjusted for patient risk markers and geographical variation. Bladder cancer was the most prevalent disease. Visible haematuria was the strongest predictor for urinary tract cancer