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Tytuł:
Personal values and life meanings of Ukrainian youth in the conditions of instability
Autorzy:
Khoruzha, Liudmyla
Powiązania:
https://bibliotekanauki.pl/articles/52914975.pdf
Data publikacji:
2024-12-31
Wydawca:
Wydawnictwo Adam Marszałek
Tematy:
values
social experience
meaning of life
Ukrainian youth
conditions of instability and uncertainty
emotional and psychological state
restructuring of the sphere of values
Opis:
The article comprises a static scientific-analytical review of the values and life meanings of Ukrainian youth in the conditions of war. The instability of the situation is characterized by the life circumstances that continue for a long time and significantly go beyond the social and natural norms in which people are used to living. In this social context, the value paradigm of a person is changing. On the basis of statistical data, a quantitative and qualitative analysis of the problems that concern Ukrainian youth today was carried out, the types of their social activity, life priorities and meanings, dominant factors that influence the process of personality formation were determined. It is also stated in the study that the formation of the young people’s value foundations during the war is influenced by their emotional and psychological state, which in most cases is not stable and has a contradictory and changeable character. Extremeness and categoricalness in assessments, frequent changes in emotional moods and priorities in young people are a result of the experienced stress. Some important generalizations are made regarding the restructuring of the value sphere of young people under the influence of such a tragic socio-political phenomenon as war.
Źródło:
Edukacja Międzykulturowa; 2024, 27, 4; 103-113
2299-4106
Pojawia się w:
Edukacja Międzykulturowa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of progressive collapse of a super-long span latticed steel arch structure
Autorzy:
Guo, Shuangchao
Xu, Delin
Shang, Kaiguang
Yang, Shuo
Wang, Di
Li, Gen
Zheng, Bing
Jiao, Yong
Powiązania:
https://bibliotekanauki.pl/articles/2200875.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
progressive collapse
steel arch truss structure
compression instability
Opis:
The progressive collapse of a space grid structure which has a large number of members and a large span is the focus of current research. Before the progressive collapse of the structure, there is a problem of instability of the members. In this paper, dynamic nonlinear analysis of a super-long span latticed steel arch structure is carried out to study its progressive collapse process using a Kinematic Hardening Plasticity constitutive model compiled by Vumat material subprogram in Abaqus, which takes into account instability of the members. Differences in the dynamic response process of the structure at the collapse moment and the failure sequence of the members using the member stability model and the material failure constitutive model are compared. Compared with the material failure constitutive model, when the member stability constitutive model is used, the proportion of compressive buckling members in the structural failure is higher, and the bearing capacity of the structure is lower when the initial failure occurs. The structure suffers from localized member compressive failure rather than material yielding, which leads to the progressive collapse of the structure.
Źródło:
Journal of Theoretical and Applied Mechanics; 2023, 61, 1; 103--117
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Drilling fluids in complicated conditions: a review
Płuczki wiertnicze w skomplikowanych warunkach: przegląd
Autorzy:
Shmoncheva, Yelena Y.
Jabbarova, Gullu V.
Abdulmutalibov, Timur E.
Powiązania:
https://bibliotekanauki.pl/articles/31348244.pdf
Data publikacji:
2023
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
extended reach wells
wellbore instability
drilling fluids
mud loss
shale stabilization
geomechanical factors
mud weight
filter cake
polymer system
optimization
odwierty o wydłużonym zasięgu
niestabilność odwiertu
płyny wiertnicze
ucieczki płuczki
stabilizacja łupków
parametry geomechaniczne
ciężar właściwy płuczki
placek filtracyjny
system polimerowy
optymalizacja
Opis:
The review in this article focuses on various aspects of drilling extended reach (ERD) wells. Reaching extreme depths and setting world records for deviation illustrates the importance of well design and operating strategies. Studies of articles describing various locations, including Sakhalin Island in Russia and offshore Vietnam, provide insight into ERD operations. Furthermore, the challenges of drilling in specific geological conditions, such as layered sandstones and reactive clay, are considered. Particular attention is paid to issues related to wellbore instability and drilling fluid optimization. The results of technical studies highlight the key role of maintaining wellbore stability in achieving successful ERD results. The articles emphasize the importance of understanding geomechanical factors, employing optimal mud weight, lubrication, and specialized drilling fluids to counteract instability. It demonstrates that maintaining appropriate mud weights and employing specific drilling techniques are crucial for mitigating instability-related issues. The integration of mechanical and chemical approaches is advocated for effectively managing shale-related instability. The utilization of innovative materials and fluid systems is central to the successful resolution of stability-related problems. The incorporation of micronized sealing polymers in conjunction with conventional plugging materials is detailed as an effective approach to counter wellbore instability. The synergistic combination of materials, additives and mud salinity is showcased to achieve effective shale stabilization and optimize drilling time. The authors emphasize the importance of selecting the optimal composition for each well based on experience and laboratory testing and present laboratory-tested solutions that have been successfully applied in field operations. In summary, these articles collectively offer insights into a range of strategies to combat wellbore instability. They cover the use of advanced materials, innovative fluid systems, and chemical approaches to maintain wellbore stability, improve drilling efficiency, and reduce nonproductive time.
Przegląd zawarty w niniejszym artykule skupia się na różnych aspektach wiercenia odwiertów o wydłużonym zasięgu (ERD). Osiąganie ekstremalnych głębokości i ustanawianie rekordów świata w zakresie odchyleń ilustruje znaczenie projektowania odwiertu i strategii eksploatacyjnych. Przegląd artykułów opisujących różne lokalizacje, obejmujące wyspę Sachalin w Rosji oraz szelf w Wietnamie, zapewnia wgląd w operacje ERD. Ponadto rozważane są wyzwania związane z wierceniem w specyficznych warunkach geologicznych, takich jak piaskowce warstwowane oraz reaktywne iły. Szczególną uwagę zwraca się na zagadnienia związane z niestabilnością odwiertów i optymalizacją płuczki wiertniczej. Wyniki badań technicznych podkreślają kluczową rolę utrzymania stabilności odwiertu w osiąganiu udanych wyników ERD. W artykułach podkreślono znaczenie zrozumienia czynników geomechanicznych, stosowania płuczki o optymalnym ciężarze, smarowania oraz specjalistycznych płynów wiertniczych w celu przeciwdziałania niestabilności. Pokazano, że utrzymywanie odpowiedniego ciężaru płuczki oraz stosowanie specjalnych technik wiercenia ma kluczowe znaczenie dla złagodzenia problemów związanych z niestabilnością. Dla skutecznego zarządzania niestabilnością związaną z łupkami zaleca się integrację podejścia mechanicznego i chemicznego. Wykorzystanie innowacyjnych materiałów i systemów płynów ma kluczowe znaczenie dla udanego rozwiązywania problemów związanych ze stabilnością. Włączenie mikronizowanych polimerów uszczelniających w powiązaniu z konwencjonalnymi materiałami uszczelniającymi jest opisywane szczegółowo jako skuteczne podejście w celu przeciwdziałania niestabilności odwiertu. Synergiczne połączenie materiałów, dodatków oraz zasolenia płuczki jest przedstawiane jako sposób osiągnięcia skutecznej stabilizacji łupków i optymalizacji czasu wiercenia. Autorzy podkreślają znaczenie doboru optymalnego składu dla każdego odwiertu na podstawie doświadczenia i badań laboratoryjnych oraz obecne rozwiązania przetestowane laboratoryjnie, które zostały z powodzeniem zastosowane w operacjach terenowych. Podsumowując, artykuły te łącznie oferują wgląd w szereg strategii zwalczania niestabilności odwiertów. Obejmują one zastosowanie zaawansowanych materiałów, innowacyjnych systemów płynów oraz rozwiązania chemiczne w celu utrzymania stabilności odwiertu, poprawy wydajności wiercenia oraz zmniejszenia czasu nieproduktywnego.
Źródło:
Nafta-Gaz; 2023, 79, 10; 651-660
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Economic Vulnerability of Small Powers
Autorzy:
Zoidze, Gia
Abuselidze, George
Veshapidze, Shota
Powiązania:
https://bibliotekanauki.pl/articles/31341145.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Gdański. Instytut Geografii
Tematy:
small states
economic freedom
national security
GDP per capita
political instability
Opis:
The purpose of this article is to identify the national security challenges of a small state, to highlight their external and internal aspects; based on the research, develop a rational economic and political strategy for small powers. The paper is based on the analysis and synthesis of various fundamental literature and specific statistical data. The paper draws conclusions using causeand-effect relationships of facts. Important conclusions and recommendations are presented on key issues and challenges around small countries. This article concerns countries with small powers and their essential features – especially security, economic development, political stability, and foreign policy. It is also well understood today that threats of a military and nonmilitary nature are closely linked and that the aggravation of one leads to the aggravation of another. The systemic approach has taken root in the study of security issues, which involves discussing not just one but all of the potential threats in relation to one another and in one another’s context. The results of this study indicate that no matter how flexible a small country’s foreign policy is and how quickly it responds to changing conditions and events, it must still define its own strategic goal and make strategic choices. In determining its own national security priorities and foreign policy strategy, a small country must be more precise and infallible than a strong one. A small state that makes the wrong choice in its survival strategy is usually doomed.
Źródło:
Journal of Geography, Politics and Society; 2023, 13, 3; 1-12
2084-0497
2451-2249
Pojawia się w:
Journal of Geography, Politics and Society
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Social and psychological features of affective disorders in people during crisis periods of life
Autorzy:
Spytska, Liana
Powiązania:
https://bibliotekanauki.pl/articles/28408761.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
mental health
environmental instability
psychocorrection
katathym type
mature personality
Opis:
The study’s relevance is due to the association between mental disorders and environmental instability. A frequent consequence of stress is post-traumatic disorder, which can significantly affect the personality and disrupt adaptation, causing subjective suffering. The purpose of the article is to update information on the structure and dynamics of socio-psychological features of affective personality disorders in the crisis period of life in the Ukrainian population associated with the war. The article uses the following methods: clinical and psychological, psychometric, and statistical (in particular, descriptive statistics) methods. The results of the study demonstrate various courses of bipolar affective disorders of the continuum type with the transformation of their dynamics. The study showed a significant increase in the negative symptoms of affective disorders under the influence of stress. The researchers demonstrated the severity of both depressive and manic phases of affective disorders under the impact of stress factors. The results indicate an exacerbation of the course of affective disorders in people under difficult life circumstances. The findings have theoretical significance and are promising for further research on typologisation, classification and identifying clinical and biological manifestations to represent the specifics of pathogenesis.
Źródło:
Society Register; 2023, 7, 4; 21-36
2544-5502
Pojawia się w:
Society Register
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Static instability of an inverted plate in channel flow: state-space representation and solution approximation
Autorzy:
Li, P.
Zhang, D.
Cui, J.
Yin, H.
Yang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/38697113.pdf
Data publikacji:
2023
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
inverted cantilevered plate
static aeroelastic instability
channel flow
state-space representation
Glauert’s series
the least squares method
Opis:
Plate-like structures in channel flow are commonly found in engineering. This paper reports a theoretical study on the static aeroelastic instability of an inverted cantilevered plate in an inviscid channel flow through the state space. This study begins with the kernel function of the flow potential determined in the Fourier domain with the help of the mirror image method. Then, the instability equation is derived from the operator theory and transformed in the state space. Finally, with Glauert’s expansion, model functions, and error functions, the instability problem of such a plate has been modeled as a mathematical function approximation problem and solved by the least squares method. The derived instability equation is considered at the continuum level of description, and no approximation appears at the first equation level. The convergence and reliability of the proposed modeling and its solutions approximation are entirely tested, and it can successfully predict the instability boundary, behavior, and the channel effect. Numerical results show that the decreased channel height and asymmetric plate placement in the channel significantly decrease the critical flow velocity. The plate instability modes are close to the plate’s first natural ones and not sensitive to the channel parameters. This conclusion allows further theoretical exploration of a semi-analytical approximation of the instability boundary from the obtained instability equation. The current modeling strategy in a continuum sense may provide a new idea and essential reference for other instability problems.
Źródło:
Archives of Mechanics; 2023, 75, 6; 695-727
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
War and Food (In)security - A Lesson from the Russian-Ukrainian Conflict
Autorzy:
Iacovino, Angela
Andreotti, Alessandro
Rago, Sara
Powiązania:
https://bibliotekanauki.pl/articles/2189676.pdf
Data publikacji:
2023-04-14
Wydawca:
Uniwersytet Warszawski. Centrum Europejskie
Tematy:
Food Security
War
Crisis
Russia
Ukraine
Energy Instability
European Union
Opis:
The Russian invasion of Ukraine has implemented legitimate fears of a global crisis and further and inevitably aggravating existing food-security challenges. The international community is being called upon to take targeted action to address the rapidly-evolving, resultant scenarios, making it essential to go beyond immediate interim measures and to re-examine the agricultural and energy policies that underpin our global economy. This article, without any claim to exhaustiveness, examines the inevitable link between war and the dynamics related to food security. In the first instance, a theoretical-interpretative key of the logics of violent conflicts that generate a relevant impact on global food supplies and food (in)security is provided, within the broader framework of the dynamics related to the instability of international relations which hinder the supply of energy resources and determine the volatility of general price levels. In the concluding section, there is reflection crossed reference to the ongoing Russia/Ukraine conflict as well as the devastating consequences on global food systems, already put under stress by the COVID-19 pandemic.
Źródło:
Studia Europejskie - Studies in European Affairs; 2023, 27, 1; 99-126
1428-149X
2719-3780
Pojawia się w:
Studia Europejskie - Studies in European Affairs
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Artroskopowa operacja Latarjet: wyniki kliniczne leczenia 156 pacjentów z minimum 2-letnim okresem obserwacji
Arthroscopic Latarjet Procedure with 2-Screw Stabilization: Results of Treatment of 156 Cases with a Minimum of 2-Year Follow-Up. Multicenter Study
Autorzy:
Brzóska, Roman
Błasiak, Adrian
Solecki, Wojciech
Laprus, Hubert
Kiciński, Maciej
Grzegorzewski, Andrzej
Kordasiewicz, Bartłomiej
Powiązania:
https://bibliotekanauki.pl/articles/28409208.pdf
Data publikacji:
2022-09-20
Wydawca:
Fundacja Edukacji Medycznej, Promocji Zdrowia, Sztuki i Kultury Ars Medica
Tematy:
artroskopia
niestabilność stawów
staw ramienny
wyniki
arthroscopic treatment
joint instability
shoulder joint
outcomes
Opis:
Wstęp. Artroskopowe leczenie operacyjne niestabilności stawu ramiennego wiąże się z dużym odsetkiem opisywanych nawrotów- od 10,8% do 21,1%. Nawroty występują najczęściej u młodych mężczyzn uprawiających sporty kontaktowe. Ubytki kostne głowy kości ramiennej i panewki, predysponują do kolejnych zwichnięć i do niepowodzenia leczenia chirurgicznego. Jest to grupa, w której zabiegi „kostne”, takie jak artroskopowa procedura Latarjet a priori, mogą zminimalizować ryzyko nawrotu niestabilności. Materiał i metody. Do badania włączono pacjentów z urazową, jednokierunkową niestabilnością przednią stawu ramiennego, leczonych od 2009 do 2016 roku w dwóch ośrodkach artroskopową metodą Latarjet. Oceniono wyniki kliniczne, w tym zakres ruchu, Subiektywną Ocenę Stawu Ramiennego i punktację w skali Walch-Duplay. Odnotowano powikłania pooperacyjne. Wyniki. Ocenie poddano 156 pacjentów w okresie co najmniej 2 lata po operacji. Średni czas obserwacji wyniósł 43±18 miesięcy. Średni wiek pacjentów w momencie operacji wynosił 27,9 (16-53) lat. Odnotowano 8 (5%) przypadków nawrotu niestabilności, w tym 6 zwichnięć i dwa przypadki nawracającego podwichnięcia operowanego stawu. Średnia punktacja Walch-Duplay wzrosła z 30±19 przed operacją do 83±16 (p<0,05). Średnia utratę rotacji zewnętrznej wynosiła 11,8⁰ (0-70) (p<0,05) w porównaniu ze stawem ramiennym po stronie przeciwnej. Średnia Subiektywna Ocena Stawu Ramiennego wyniosła 92,8±9,4%. Dwudziestu pięciu (15,8%) pacjentów zgłaszało subiektywną obawę przed powrotem do sportu. Jedenastu (7%) pacjentów odczuwało ból przedniego przedziału operowanego barku. Liczba operacji rewizyjnych wyniosła 14 (8,9%). Wnioski. 1. Artroskopowa procedura Latarjet zapewnia zadowalające wyniki kliniczne w leczeniu niestabilności przedniej stawu ramiennego. 2. Częstość powikłań i nawrotów nie wzrasta z czasem i jest porównywalna z wynikami opisanymi w piśmiennictwie.
Background. Various arthroscopic stabilization procedures are associated with recurrence rates ranging from 10.8% to 21.1%. Recurrences occur especially in young male patients participating in contact sport activities. Bony defects of the humeral head and the glenoid predispose not only to subsequent dislocations but also to failure of surgical treatment. This is the group where "bony" procedures such as arthroscopic Latarjet are recommended to provide better stability as the primary treatment. Material and methods. Patients with traumatic unidirectional anterior shoulder instability treated from 2009 to 2016 with an arthroscopic Latarjet procedure operated on in two centres. Clinical results, including range of motion, Subjective Shoulder Value and Walch-Duplay score, and postpoperative complications were evaluated. Results. 158 patients were available for follow-up at a minimum of 2 years after surgery. The mean follow-up was 43±18 months. Mean age at the time of surgery was 27.9 (16-53) years. At final follow-up, 8 cases of recurrent instability were identified, including 6 cases of recurrent dislocation and two cases of recurrent subluxation. Mean Walch-Duplay score increased from 30±19 preoperatively to 83±16 (p<0.05) at the last follow-up. An average loss of external rotation of 11.8⁰ (0-70) (p<0.05) when compared with the contralateral shoulder was observed at the last follow-up. Mean Subjective Shoulder Value score was 92.8±9.4%. 8 (5%) patients presented with loss of shoulder stability. 25 (15.8%) patients reported subjective return to sport anxiety. Eleven (7%) patients complained of anterior compartment pain. The total number of revision surgeries was 14 (8.9%). Conclusions. 1. The arthroscopic Latarjet procedure can achieve satisfactory clinical outcomes for the treatment of anterior shoulder instability 2. The rate of complications and recurrence does not increase with time and is comparable at a minimum of 2 years’ follow-up to early results described in literature.
Źródło:
Ortopedia Traumatologia Rehabilitacja; 2022, 24(4); 223-237
1509-3492
2084-4336
Pojawia się w:
Ortopedia Traumatologia Rehabilitacja
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of liquefaction potential for loose minefill slopes
Autorzy:
Kudella, P.
Powiązania:
https://bibliotekanauki.pl/articles/1954561.pdf
Data publikacji:
2022-02-07
Wydawca:
Politechnika Gdańska
Tematy:
liquefaction
granular materials
hypoplasticity
instability
failure
Opis:
Uncompacted embankments of certain fine sands exhibit a spontaneous liquefaction potential, which cannot be evaluated basing on undrained shear strength alone. A novel procedure for stability analysis has been developed, basing on Hill's stability criterion and a hypoplastic constitutive law. With given relative densities, assumed initial stress states and variations of perturbation directions, stability or instability of slope sections can be assessed. Catastrophic landslides observed in the past could thus be explained.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 3; 439-451
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Functional Instability of the Second to Fifth Metacarpophalangeal Joints
Autorzy:
Sulyma, Vadym
Kovalyshyn, Taras
Sribniak, Andrii
Bihun, Roman
Krasnovskyi, Vladyslav
Filiak, Yuliia
Powiązania:
https://bibliotekanauki.pl/articles/28408852.pdf
Data publikacji:
2022-03-02
Wydawca:
Fundacja Edukacji Medycznej, Promocji Zdrowia, Sztuki i Kultury Ars Medica
Tematy:
joint instability
metacarpophalangeal joint
non-parametric statistics
healthy volunteers
Opis:
Background. Clinically, functional instability (FI) of metacarpophalangeal joints (MCPJ) is not considered to represent a pathology. This excessive mobility can be detected by the application of external forces to a MCPJ at different angles. Our study aimed to measure the FI of 2nd to 5th MCPJ. Materials and methods. A group of 36 healthy right-handed individuals were enrolled. The value of FI was measured in millimeters and verified by a CT scan. Statistical calculations was made in Statistica v.10.0. Results. The largest values of the right and left-hand finger posterior displacement (FI) in the second to fifth MCPJ were obtained in the neutral position 0° (p<0.05). Measurements of volar displacement of the proximal phalanx second to fifth MCPJs in both hands revealed higher values at position 0° (p<0.05). Conclusions. 1. FI of the second to fifth MCPJs is determined by anatomical configuration and dynamic stabilizers. 2. Instability measurements show that posterior displacement of the proximal phalanges is greater by at least 1 mm in the 0° neutral position.
Źródło:
Ortopedia Traumatologia Rehabilitacja; 2022, 24(1); 23-30
1509-3492
2084-4336
Pojawia się w:
Ortopedia Traumatologia Rehabilitacja
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On a couple-stress Rivlin-Ericksen ferromagnetic fluid heated from below with varying gravity, rotation, magnetic field and suspended particles flowing through a porous medium
Autorzy:
Rahul
Sharma, Naveen
Powiązania:
https://bibliotekanauki.pl/articles/2174204.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
niestabilność termiczna
pole magnetyczne
płyn ferromagnetyczny
naprężenie
thermal instability
magnetic field
couple-stress fluid
ferromagnetic fluid
suspended particles
Opis:
The thermal instability of a couple-stress Rivlin-Ericksen ferromagnetic fluid with varying gravity field, suspended particles, rotation and magnetic field flowing through a porous medium is investigated. The dispersion relation has been developed and solved analytically using the normal mode approach and linear stability theory. The effect of suspended particles, rotation, couple stress, permeability and magnetic field on the fluid layer has been investigated. For stationary conventions, it is found that suspended particles always have a destabilizing effect for λ>0 and a stabilizing effect for λ<0 and couple-stress, magnetic field and permeability of the medium have a stabilizing effect on the thermal instability under certain conditions. In the absence of the rotation couple-stress has a stabilizing effect if λ >0 and a destabilizing effect if λ<0. Rotation has a stabilizing effect if λ >0 and a destabilizing effect if λ<0. In the absence of rotation permeability has a stabilizing effect if λ<0 and a destabilizing effect if λ>0. Magnetisation always has a stabilizing effect ( λ>0 or λ<0).
Źródło:
International Journal of Applied Mechanics and Engineering; 2022, 27, 2; 177--198
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Political instability as a risk factor for PPP project success – a case study of the Hungarian M1/M15 motorway project
Autorzy:
Schulders, Maria
Powiązania:
https://bibliotekanauki.pl/articles/27313690.pdf
Data publikacji:
2022
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
public-private partnership
risk allocation
political instability
PPP barriers
critical success factors
partnerstwo publiczno-prywatne
alokacja ryzyka
niestabilność polityczna
bariery PPP
krytyczne czynniki sukcesu
Opis:
Purpose: The main aim of this paper is to analyze political instability as a risk factor for public-private partnership (hereinafter: PPP) project success on the case of the 1992 Hungarian M1/M15 motorway project. Furthermore, it also examines the project success framework and critical success factors in PPPs, as well as project risk division and proper risk allocation. Design/methodology/approach: The text includes a review of relevant literature in the field of political instability and risk management pertaining to PPPs, in combination with a case study illustrating the impact of political instability on a PPP project. Findings: The findings of the case study suggest that Hungary’s institutions at the time of the project did not offer the necessary safeguards against governmental abuse of bargaining power. Independent courts are essential for the success of public-private partnerships, in combination with an emphasis on the protection of property rights and the rule of law. A well-functioning institutional and legal framework offer protection against the failure of public-private partnership projects and constitute a critical success factor for PPPs. Practical implications: Despite growing social infrastructure investment needs, PPP is not developing in accordance with expectations in the majority of developing and emerging economies. Political stability is an essential factor in any development process and happens to be one of the most distinguishing factors between developed and developing countries, in which PPP schemes are underutilized despite an enormous potential for more private sector involvement. Countries lacking independent courts may strongly benefit from alternative dispute resolution procedures. The retention of a larger amount of project risk by the public party may additionally prove to be helpful for the development of PPP markets in nations lacking institutional and political stability. Originality/value: The research problem identified in this paper concerns the implications of political instability – a global phenomenon of growing significance, on the success of PPP projects. The obtained results may be of interest to representatives of science and practice, especially with regards to developing countries, as well as emerging economies.
Źródło:
Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska; 2022, 157; 469--482
1641-3466
Pojawia się w:
Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability-Based Assessment of Galloping Instability of Thin-Walled Steel Beams
Autorzy:
Nguyen, Huu Anh Tuan
Powiązania:
https://bibliotekanauki.pl/articles/27314733.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
instability
wind speed
Monte Carlo simulation
reliability index
safety factor
niestabilność
prędkość wiatru
Monte Carlo
wskaźnik niezawodności
współczynnik bezpieczeństwa
Opis:
Galloping instability relating to cross-wind vibrations can be found in flexible and lightly damped structures. In the present paper, the reliability of a thin-walled steel beam in maintaining its galloping stability was examined using a probabilistic approach. The analysis considered random variation in the cross-sectional geometrical properties of the beam, the material elastic modulus, the structural damping and the wind speed. A large number of Monte Carlo simulations were performed with normal and Gumbel distributions applied to the random variables to determine the probability distribution function of the safety margin. The limit state is considered violated when the wind speed exceeds the onset wind velocity of galloping, resulting in the aerodynamic damping being greater than the structural damping. It was shown by a conventional codified safety factor method that the beam was robust enough for galloping stability. By contrast, the probability-based assessment revealed that the beam failed to achieve the target reliability index in case the coefficient of variation of wind speed was greater than 5%. The analysis results suggested that the code-satisfied slenderness of the beam should be reduced by a factor of 1.5-1.7 under the action of wind speed with a coefficient of variation in the range 30-40%.
Źródło:
Civil and Environmental Engineering Reports; 2022, 32, 2; 23--35
2080-5187
2450-8594
Pojawia się w:
Civil and Environmental Engineering Reports
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transiliac Cerclage in Unstable Pelvic Ring Fractures
Autorzy:
Sanzana, Edgardo S.
Ojeda, Alvaro C.
Gonzalez-Rojas, Francisco
Lopez-Carcel, Gemma
Alfaro, Patricio A.
Melo-Aiello, Humberto
Powiązania:
https://bibliotekanauki.pl/articles/28409177.pdf
Data publikacji:
2022-07-01
Wydawca:
Fundacja Edukacji Medycznej, Promocji Zdrowia, Sztuki i Kultury Ars Medica
Tematy:
pelvic ring fractures
pelvic instability
internal fixation
cerclage
Opis:
Background. To evaluate the outcomes of transiliac cerclage with Dall-Miles cable in the internal fixation of the posterior complex in unstable pelvic ring fractures between January 1995 and December 2014. Material and methods. A study of 42 men injured at work with an average age of 35.2 years (range, 23 to 61) was conducted. The mechanisms of injury were traffic accidents in 25 cases (59.5%), crushing accidents in 12 cases (28.6%), and fall from height in 5 cases (11.9%). Thirty-six cases were polytraumatized patients (85.7%). The patients were evaluated using Majeed’s functional score and Matta’s radiological criteria. Results. The average follow-up time was 135.8 ± 45.6 months. The clinical outcomes were excellent in 17 cases (40.5%), good in 19 cases (45.2%), fair in 5 cases (11.9%), and poor in 1 case (2.4%). The radiological outcomes were satisfactory in 32 cases (76.2%) and unsatisfactory in 10 cases (23.8%). All fractures were healed. The sequelae were 3 cases (7.2%) of lower limb dysmetria and 3 cases (7.2%) of chronic neuropathic pain. Conclusion. The internal fixation of the sacroiliac complex by Dall-Miles cable cerclage reinforced with small fragment plates should be considered as an alternative method for minimally invasive osteosynthesis in selected cases of unstable pelvic ring fractures.
Źródło:
Ortopedia Traumatologia Rehabilitacja; 2022, 24(3); 143-148
1509-3492
2084-4336
Pojawia się w:
Ortopedia Traumatologia Rehabilitacja
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acute Radial Head Resection for Fracture: are We Likely to Miss an Essex-Lopresti Injury?
Autorzy:
Zhang, Dafang
Benavent, Kyra A.
Dyer, George S.M.
Earp, Brandon E.
Blazar, Philip
Powiązania:
https://bibliotekanauki.pl/articles/28409349.pdf
Data publikacji:
2021-08-21
Wydawca:
Fundacja Edukacji Medycznej, Promocji Zdrowia, Sztuki i Kultury Ars Medica
Tematy:
Essex-Lopresti injury
forearm instability
radial head excision
radial head fracture
radial head resection
Opis:
Background. Given the current available evidence, surgical treatment of radial head fracture with acute resection is controversial. The aim of this study was to determine whether acute resection of the radial head for a radial head fracture leads to longitudinal forearm instability due to a missed Essex-Lopresti injury. Material and methods. A retrospective review was conducted of radial head resections performed for acute radial head fractures at two Level I trauma centers from 2000 to 2018. A total of 11 patients met inclusion criteria. Our primary outcome was a missed Essex-Lopresti injury at time of final clinical follow-up. Long-term telephone follow-up was attempted for QuickDASH, pain scores, and satisfaction scores. Results. Of the 11 radial head fractures in this study, intraoperative radial pull tests were performed and normal in 6 patients. No patient was found to have a missed Essex-Lopresti injury at a mean of 36.2 months’ clinical follow-up after radial head resection. At a mean telephone follow-up of 12.6 years in available patients, mean QuickDASH was 3.4, mean satisfaction was 9.75 out of 10, and no further complication or reoperation was reported. Conclusion. Our findings challenge the dogma that the radial head cannot be safely excised in the setting of acute fracture, even with elbow instability and/or wrist pain, particularly when intraoperative longitudinal stability is assessed by a stress maneuver.
Źródło:
Ortopedia Traumatologia Rehabilitacja; 2021, 23(4); 263-270
1509-3492
2084-4336
Pojawia się w:
Ortopedia Traumatologia Rehabilitacja
Dostawca treści:
Biblioteka Nauki
Artykuł
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