Thin Wall Ductile Iron Castings: Technological Aspects

The paper discusses the reasons for the current trend of substituting ductile iron castings by aluminum alloys castings.However, it has been shown that ductile iron is superior to aluminum alloys in many applications. In particular it has beendemonstrated that is possible to produce thin wall wheel rim made of ductile iron without the development of chills, coldlaps or misruns. In addition it has been shown that thin wall wheel rim made of ductile iron can have the same weight, andbetter mechanical properties, than their substitutes made of aluminum alloys

Trzecie seminarium naukowe z nauk o polityce publicznej Kolegium Ekonomiczno-Społecznego Szkoły Głównej Handlowej w Warszawie Polityka publiczna w Polsce – priorytety i wyzwania

Relation. The third academic seminar on public policy of the Economic and Social College of the Warsaw School of Economics Public policy in Poland - priorities and challengesRelacja. Trzecie seminarium naukowe z nauk o polityce publicznej Kolegium EkonomicznoS-połecznego Szkoły Głównej Handlowej w Warszawie Polityka publiczna w Polsce – priorytety i wyzwani

Mathematical and numerical model of directional solidification including initial and terminal transients of the process

Abstract The, developed in this study, simple model and numerical solution of diffusion growth of the solid phase under the conditions of directional solidification allow for the effect of constituent diffusion in both liquid and solid phase and assume the process run in which (like in reality) the preset parameter is the velocity of sample (pulling velocity) at a preset temperature gradient. The solid/liquid interface velocity is not the process parameter (like it is in numerous other solutions proposed so far) but a function of this process. The effect of convection outside the diffusion layer has been included in mass balance under the assumption that in the zone of convection the mixing is complete. The above assumptions enabled solving the kinetics of growth of the solid phase (along with the diffusion field in solid and liquid phase) under the conditions of diffusion well reflecting the process run starting with the initial transient state, going through the steady state period in central part of the casting, and ending in a terminal transient state. In the numerical solution obtained by the finite difference method with variable grid dimensions, the error of the mass control balance over the whole process range was 1 -2 %

The surgical treatment of rectal cancer in Poland. The findings of a multi-center observational study by the Polish Society of Surgical Oncology (PSSO-01)

Introduction. PSSO-01, a Polish prospective multi-center project on rectal cancer, started in 2016 with participation on a voluntary basis. This study evaluates the early outcome of the surgical treatment of rectal cancer in Poland according to hospital volume. Material and methods. The dataset derives from 17 clinical centers registered in the PSSO-01 study. From 2016 to 2020, the data of 1,607 patients were collected. Taking into account the number of patients enrolled in the study, the centers were divided into three categories: high volume, medium volume, and low volume. Nominal variables were compared between different categories of centers using the chi-square test. The STROBE guidelines were used to guarantee the reporting of this observational study. Results. More patients with metastatic disease were operated on in the low volume centers (p = 0.020). Neoadjuvant treatment was used in 35%, 52%, and 66% of patients operated on in low, medium, and high volume centers respectively (p < 0.001). Laparoscopic resection in medium volume centers was performed more often than in other centers (p < 0.001). The total rate of postoperative complications related to high, medium, and low centers was 22%, 26%, 18% (p = 0.044). One year following surgery, a stoma was present in 63% of patients. A defunctioning stoma following anterior resection was reversed in only 55% of patients. Anastomotic leakage was the main reason for a non-reversal diverting stoma. Conclusions. The representation of low volume centers in the PSSO-01 study was understated. However, the outcomes may show the actual situation of surgical treatment of rectal cancer in high and medium volume centers in Poland

Automatic differentiation – selected methods comparision

W zamieszczonej w załączniku pracy dokonałem omówienia różnych metod automatycznego różniczkowania. Zaprezentowane zostały podstawowe metody kalkulacji wartości funkcji oraz jej pochodnych cząstkowych zarówno za pomocą metody propagacji w przód (FAD), jak i akumulacji wstecz (BAD). Praca zawiera również dokładnie rozpisane przykłady obliczania pochodnej kierunkowej, gradientu poprzez FAD. Przy przedstawianiu automatycznego różniczkowania z wykorzystaniem rozwinięcia funkcji w szereg Taylora, praca skupia się na dowodach pięciu wzorów potrzebnych do stosowania tej techniki.In my bachelor's paper work I discussed different methods of automatic differentiation. I have presented the methods of calculating the value of specific function and it's derivatives using both forward and reverse mode. The paper also contains examples of calculating directional derivatives and gradients. While presenting automatic differentiation using evaluation into Taylor series I mainly concentrated at proofs of both basic and more complicated arithmetics

On the mixed problem for the Poisson equation in the quart-plane

The article contains no abstrac

An institutional perspective on entrepreneurial ecosystems: variation, evolution, agency in and across organisational fields

Entrepreneurial ecosystems (EEs), understood as a type of organisational environment conducive to fostering high-growth and technology oriented startups, are currently deemed important for economic and employment growth. However, while the flagship case of Silicon Valley is widely researched and invoked, our knowledge of variation in how EEs develop is limited, and insufficiently theorised. In response, this thesis adopts an institutional perspective, conceptualising EEs as organisational fields, and addressing how the interplay between agency and structure result in different developmental trajectories of location-based EEs. The thesis consists of three empirical papers that examine several cases of EEs in Japan and India focused on Information and Communication Technology. The in-depth inductive studies are anchored in interview and participant observation data generated during multiple fieldwork visits. The findings illuminate key novel concepts: 1) a field development mechanism of intra-field cross-generational support (uncovered in an emerging field of Tokyo EE examined in relation to domestic large corporations); 2) a comparative framework of Varieties of Entrepreneurial Ecosystems (derived from an analysis of Tokyo and Bangalore – the biggest EEs in their respective countries); 3) an institutional infrastructure-related element of place cohesion (identified from a comparison of Osaka-Kyoto and Fukuoka – smaller EEs developing within one institutional context where the dominant EE is already present). Together, the papers show that differences in EE developmental trajectories stem from the interplay of EE stakeholders’ agency to develop a desired EE institutional infrastructure (which is similarly conceptualised across locations), and the underlying elements for such infrastructure (which can be very time- and location-specific). Particular agency-related mechanisms that are crucial to EE development, depend on the EE relations to other fields. Overall, the thesis contributes to the scholarship on EEs and organisational fields, enhancing more contextualised understanding of EEs, and suggesting how to better study fields in a comparative and interconnected perspective. </p