Artificial Neural Network System for Predicting Cutting Forces in Helical-End Milling of Laser-Deposited Metal Materials

When machining difficult-to-cut metal materials often used to make sheet metal forming tools, excessive cutting force jumps often break the cutting edge. Therefore, this research developed a system of three neural network models to accurately predict the maximal cutting forces on the cutting edge in helical end milling of layered metal material. The model considers the different machinability of individual layers of a multilayer metal material. Comparing the neural force system with a linear regression model and experimental data shows that the system accurately predicts the cutting force when milling layered metal materials for a combination of specific cutting parameters. The predicted values of the cutting forces agree well with the measured values. The maximum error of the predicted cutting forces is 5.85% for all performed comparative tests. The obtained model accuracy is 98.65%

Prostorsko dojemanje Sredozemlja v slovenski Istri

Prostorsko dojemanje Sredozemlja v slovenski Istri. Analiza s pomočjo teorije mehkih množi

The spatial cognition of Mediterranean in Slovenia: (In)consistency between perception and physical definitions

On the basis of a previously tested method, the cognition of the spatial extent of the Mediterranean in Slovenia is presented. The Mediterranean may be determined on the basis of numerous and very diverse criteria. It is therefore a very subjectively determined notion, where geographical and non-geographical definitions can be treated as equivalent. The research made use of a questionnaire method, which revealed the opinions of the inhabitants living in the area, generally regarded as being Mediterranean. The determination of the Mediterranean was achieved with the aid of a special question. Respondents were asked to graphically delineate its border in Slovenia on a specially prepared general map included in the questionnaire on the basis of their subjective complex perception of the characteristics by them understood as Mediterranean. The questionnaire was spatially structured by the following regions: Slovene Istria, the Vipava Valley, the Vipava Hills, the Goriška ravan, the Brda Hills, the Kras, the Pivka Basin, the Reka Valley, the Brkini Hills and the Matarsko podolje and Ljubljana with its surroundings. By drawing on the fuzzy logic theory and helped by computer techniques all the answers were merged on a special map showing the extent and membership of the fuzzy set “Mediterranean” within the crisp set “Slovenia”. The border between the Mediterranean and non-Mediterranean part of Slovenia is in this way established as a continuous transition. The mean value of this transition goes from Šempeter, passes the eastern flank of Karst, beside Divača and ends on the eastern side of Slavnik. A more restrictive criterion of the membership function value of 0.95, includes in the Slovenian Mediterranean only the sea and its most immediate hinterland. Particularly interesting proved differences in the spatial cognition of the Mediterranean’s borders in Slovenia between different survey regions

CAD Based Electric Transporter Path Planning and Production Storage Optimization Using Genetic Algorithm – Industrial Case Study

Štore Steel Ltd. is one of the largest flat spring steel producers in Europe. There are two production lines after rolling – one for flat bars and the other for round bars. The flat bars production generally consists of visual examination, straightening and cutting operation. In addition, heat treatment or magnetic particle testing could be conducted. On the other hand, the round bars production consists generally of straightening, automatic control line control, chamfering and cutting. In addition, heat treatment is possible. For manipulation of the material in the rolling plant, the electric transporter and several cassettes are used. In the paper path planning and production storage optimization (i.e. storage spaces for cassettes) were conducted using genetic algorithm. The production storage is actually the space between main transport passage and individual operations. In the research the universal system using CAD geometry is presented where AutoCAD environment and in-house developed AutoLISP system were used. The production storage – storage spaces for cassettes (location and orientation) with corresponding electric transporter trajectories are represented as CAD objects and thus form individual solution/organism. The organisms undergo simulated evolution. The results of the evolution are compared with actual production storage in the steel plant

Predicting of Roll Surface Re-Machining Using Artificial Neural Network

The paper presents a model for predicting the roll wear in the hot rolling process. It includes all indicators from the entire continuous rolling line that best predict the roll wear in the hot rolling process. Data for model development were obtained from annual production on the first rolling stand of the continuous roll mill. The main goal of the research was to determine significant parameters that affect the wear of the roll in the process of hot rolling. It has been found that the amount of rolled material before the re-machining of the roll surface has the greatest impact on the life of the roll contour. Therefore, the amount of material rolled before re-machining of the roll was used to estimate the wear of the roll. An artificial neural network was used to predict this amount of rolled material and was validated using data from one-year production

Preprečevanja zgodnjih invazivnih okužb novorojenčka zaradi streptokoka skupine B – mikrobiološke metode za ugotavljanje nosilstva pred in ob porodu

Ob koncu lanskega leta je Zdravstveni svet Republike Slovenije potrdil program preprečevanja zgodnjih invazivnih okužb novorojenčkov, povzročenih s streptokokom skupine B, ki vključuje univerzalno presejanje nosečnic v 35.–37. tednu nosečnosti. V prispevku smo pregledali različne diagnostične metode presejanja in dejavnike, ki pomembno vplivajo na njihovo uspešnost tako v ginekološki ambulanti kakor tudi v mikrobiološkem laboratoriju. Bralca opozarjamo na pravilnost odvzema kužnine, mu predstavimo izbrano strategijo testiranja s kombinacijo obogatene kulture in molekularnega testiranja ter mu ponujamo seznam registriranih molekularnih testov, primernih za testiranje. V zadnjem delu prispevka razpravljamo o pomenu hipervirulentnega klona CC-17, ki povzroča večino invazivnih okužb novorojenčkov v Sloveniji, in o metodah, s katerimi ga prepoznamo

Retrospective analysis of the frequency and severity of radiation-induced skin injuries from interventional radiology procedures

Cilji: Zanimalo nas je kako pogosto in kakšne poškodbe na koži je povzročila obsevanost pacientov pri interventnih radioloških posegih z dozo v interventni referenčni točki nad 3 Gy. Metode: V raziskavi smo retrospektivno pregledali 7607 pacientov. Med njimi smo izbrali paciente, za katere je kerma v intervencijski referenčni točki presegla 3 Gy in pri 72 od teh (1% celotnega vzorca) z anketnimi vprašalniki preverili morebitne poškodbe na koži. Da bi ovrednotili ustreznost kerme v intervencijski referenčni točki za oceno kožne doze smo pri 16 pacientih, pri katerih smo pričakovali visoko dozo, kožno dozo izmerili z GAF Chromic filmi. Rezultati: Izmed 7607 pacientov je kerma v intervencijski referenčni točki presegla 3 Gy pri 145 pacientih, pri čemer je bila ta meja najpogosteje presežena pri vstavitvah endovaskularnih stent graftov. Od 35 vrnjenih anketnih vprašalnikov 29% pacientov poroča o poškodbah na koži. Pri meritvah z GAF Chromic filmi smo v povprečju opazili dobro ujemanje z izpisano vrednostjo kerme v intervencijski referenčni točki, vendar so se pri posameznih pacientih pokazala velika odstopanja med obema vrednostnima. Sklepi: Vrednost doze v interventni referenčni točki, ki jo poda aparatura, pri večini pacientov relativno dobro odraža najvišjo vstopno kožno dozo. Kožna doza je presegla prag za nastanek determinističnih poškodb pri približno 2% pacientov, o poškodbah na koži pa je poročalo približno 0,6% pacientov. Zaključek: Raziskava predstavlja sistematičen pregled pogostosti pojavljanja determinističnih poškodb kože pri posegih v intervencijski radiologiji. Čeprav poročane vrednosti odražajo prakso na Kliničnem inštitutu za radiologijo UKC Ljubljana, rezultati podajajo orientacijske vrednosti, ki so relevantne tudi v širšem okviru.Objectives: We assessed the level and frequency of radiation-induced skin injuries to patients undergoing interventional radiology procedures at the University Medical Centre Ljubljana in the period from 2012 to 2014. . Methods: In the study 7,607 interventional radiology patients were retrospectively reviewed. Among them, we identified 145 patients for whom Kerma in the intervention reference point (K_IRP) exceeded 3 Gy. Data about the observed skin injuries were gathered by a questionnaire that was sent to 72 patients (1% of the total sample) of whom 35 responded. Reliability of K_IRP for assessing entrance skin dose was confirmed by measuring peak skin dose by GAF chromic dosimetry films in 16 patients for whom we expected high skin doses. Results: The peak skin dose as estimated by K_IRP exceeded 3 Gy threshold in approximately 2% of all interventional radiology patients includes in the study. This was most frequently the case in endovascular stent grafts insertions. Extrapolation of the received feedback to the questionnaires indicates that skin injury was observed by approximately 30 % of the patients with K_IRP above 3 Gy or in approximately 0.6 % of all patients included in the study. . Measurements with GAF chromic films in general showed good agreement with the Kerma in the intervention reference point as provided by the fluoroscopy system although significant discrepancies between the two values were observed for individual patients . Conclusions: In interventional radiology procedures peak skin dose can exceed the threshold for radiation-induces skin injuries in a significant number of patients (2 %) even if great attention is given to optimization of the use of ionizing radiation. The actual skin injuries were reported approximately 3 times less frequently than anticipated based on the accepted thresholds for deterministic effect and their severity was poorly related to the estimated peak skin doses. Advances in Knowledge: The study presents a systematic review of the incidence of deterministic skin injuries in interventions in interventional radiology. While the reported values reflect the specific practice at the Clinical Institute of Radiology, University Medical Centre Ljubljana, the results are relevant in a wider context

Modeling of Tensile Test Results for Low Alloy Steels by Linear Regression and Genetic Programming Taking into Account the Non-Metallic Inclusions

Štore Steel Ltd. is one of the biggest flat spring steel producers in Europe. The main motive for this study was to study the influences of non-metallic inclusions on mechanical properties obtained by tensile testing. From January 2016 to December 2021, all available tensile strength data (472 cases–472 test pieces) of 17 low alloy steel grades, which were ordered and used by the final user in rolled condition, were gathered. Based on the geometry of rolled bars, selected chemical composition, and average size of worst fields non-metallic inclusions (sulfur, silicate, aluminium and globular oxides), determined based on ASTM E45, several models for tensile strength, yield strength, percentage elongation, and percentage reduction area were obtained using linear regression and genetic programming. Based on modeling results in the period from January 2022 to April 2022, five successively cast batches of 30MnVS6 were produced with a statistically significant reduction of content of silicon (t-test, p < 0.05). The content of silicate type of inclusions, yield, and tensile strength also changed statistically significantly (t-test, p < 0.05). The average yield and tensile strength increased from 458.5 MPa to 525.4 MPa and from 672.7 MPa to 754.0 MPa, respectively. It is necessary to emphasize that there were no statistically significant changes in other monitored parameters