Numerical Modeling of Copper Tube Extrusion: Process and Eccentricity Analysis

Author(s):  
Luigi De Pari ◽  
Wojciech Z. Misiolek

In order to simulate copper extrusion more closely to industrial practices and to analyze the roots of the complicated issue of tube eccentricity, the material properties and the extrusion conditions were simulated using the finite element modeling (fem) software package, DEFORMTM-3D. This allowed prediction of stress, strain, strain rate, and temperature conditions within the billet during various processing conditions. These state variables were considered when ascertaining the influence of degree of billet upset and tool misalignment on tube eccentricity. It was found that under ideal upset conditions and perfect tool alignment, the tube eccentricity was minimized. If the piercer (or mandrel) was aligned with an initial angular or parallel misalignment that was still within tolerance the impact on eccentricity initially is minor in comparison to the eccentricity produced toward the end of extrusion, with the angular misalignment scenario being the more severe case. As a result, an angular misalignment is more detrimental than a parallel misalignment for tube preform eccentricity with the given forming parameters.

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1096
Author(s):  
Mario Cotacallapa-Sucapuca ◽  
Erika N. Vega ◽  
Helayne A. Maieves ◽  
José De J. Berrios ◽  
Patricia Morales ◽  
...  

The development of new food products obtained by extrusion processing has increased in recent years. Extrusion is used by the food industry to produce a wide variety of food products, such as ready-to-eat foods (e.g., snacks), among others. Pulses have also gained popularity as novel food ingredients in the formulation of a variety of food and food products, due to their high content of macro and micronutrients, and bioactive compounds that improve the nutritional and functional properties of the final food products. In this review, the impact of extrusion variables on proteins, carbohydrates, vitamins, phenolics and antinutritional compounds in pulses and pulse-based formulations are highlighted. Particularly, the impact of the specific mechanical energy. Also, the preservation, increase and/or reduction in those functional compounds, as a consequence of different extrusion processing conditions, are discussed.


2014 ◽  
Vol 6 (5) ◽  
pp. 538-545
Author(s):  
Vytautas Balevičius ◽  
Stasys Steišiūnas ◽  
Gintautas Bureika

The paper analyses the running smoothness of the rolling-stock as the main feature of wagon dynamics. The running smoothness of the freight wagon is evaluated considering the parameters of vibrations and the oscillation process. During the process of wagon running on the track, the forced oscillations of the elements of the body, chassis and suspension are excited. Four-axle freight wagon movement down the track taking into account the given vertical and lateral irregularities has been simulated using software package “Universal Mechanism”. The dependencies of the oscillation amplitudes of the wagon body on track irregularities and vertical and lateral suspension settings have been defined. The dependencies of wagon suspension settings and derailment stability on changes in the wagon mass have been examined in the paper. Finally, basic conclusions have been given. Straipsnyje nagrinėjama viena pagrindinių vagono dinamikos savybių – važiavimo tolygumas. Riedmenų važiavimo tolygumas vertinamas jų masių svyravimo proceso ir kėbulo vibracijų parametrais. Vagonui važiuojant bėgių kelio nelygumais, sužadinami priverstiniai kėbulo, pakabos ir važiuoklės elementų svyravimai. Programiniu paketu „Universal Mechanism“ sumodeliuotas prekinio keturašio vagono važiavimas keliu, kuriame yra bėgių vertikalių ir skersinių nelygumų. Nustatyta vagono kėbulo svyravimų amplitudžių priklausomybė nuo bėgių kelio nelygumų bei vertikaliųjų ir skersinių pakabos parametrų. Straipsnyje nagrinėjama vagono pakabos parametrų ir stabilumo nuriedėjimui nuo bėgių atveju priklausomybė, kintant vagono masei. Pabaigoje pateiktos išvados.


Author(s):  
Alizaman D. Gamon ◽  
Mariam Saidona Tagoranao

This study discusses the penetration of Islam in the Philippines, particularly the third wave of its expansion, which was brought by Sufi missionaries. It reinstates the historical relevance of Sufi ideas and approaches due to its contemporary relevance to the concept of social co-existence. The rational, intellectual and philosophical dimension of Islam is manifested in the cultural and traditional life of Muslim communities. The study also analyzes the impact of Muslim struggle for the development of Islamic institutions in the context of the secular state. The ongoing, unsettled debate between Islamic and government approaches to peace and development in Mindanao and Sulu continues unabated. Over the years, reforms were introduced, but in their midst, evidence of government biases and prejudices with regards to Islamic institutions have surfaced. Muslim leaders and intellectuals responded in the context of historical rights and freedom, but those views were often questioned as they are presumed to be incompatible with the national agenda for national unity. It was very recently that this incompatibility was readdressed giving support to having lasting peace and justice in Mindanao. The study argues that there have been substantial state-sponsored reforms which may contribute to the gradual advancement of Muslim communities. Though the path for the passage of Muslim concerns within the given condition is fragile and open to challenges, the study recognizes the prominence of inter-civilizational dialogue, from which the universal values of humanity will be embraced by both Muslim and non-Muslim policy makers. In addition, Muslim and non-Muslim communities in the Philippines need to embrace the universal principle of humanity and coexistence due to its relevance to the political stability and economic growth in the country.  Keywords: Muslims in the Philippines, Islamic institutions, Islamization, Muslim intellectuals, Reform. Abstrak Kajian ini mengkaji tentang kemasukan Islam, terutamanya gelombang ketiga perkembangannya, yang dibawa oleh para pendakwah sufi. Kajian itu mengembalikan semula sejarah penting tentang idea-idea dan pendekatan Sufi yang boleh digunapakai pada masa kini untuk mewujudkan keharmonian sosial di kalangan rakyat pelbagai agama. Pemahaman tentang Islam mempunyai pengaruh yang jelas terhadap kebudayaan dan tradisi Islam. Kajian ini juga menganalisis kesan perjuangan Muslim untuk pembangunan institusi Islam dalam konteks sebuah negara sekular. Perbahasan yang berterusan yang tidak menemukan penyelesaian antara pendekatan Islam dan pendekatan kerajaan untuk perdamaian serta pembangunan di Mindanao dan Sulu terus berlanjutan. Walaupun  bertahun-tahun pembaharuan telah dilakukan, namun terdapat bukti penolakan dan prasangka buruk kerajaan terhadap institusi Islam. Para pemimpin dan intelektual Muslim bertindak berdasarkan pada fakta sejarah dan hak kebebasan bersuara, namun pandangan mereka sering dipertikaikan kerana mereka dianggap tidak seiring dengan agenda dan perpaduan nasional. Baru-baru ini ketidakserasian ini mulai disuarakan semula untuk mendapat sokongan terhadap keamanan dan keadilan yang berterusan di Mindanao. Kajian ini mendapati bahawa terdapat pembaharuan yang dilakukan oleh pihak kerajaan yang boleh menyumbang ke arah  kemajuan masyarakat Islam secara beransur-ansur. Walaupun pendekatan bagi memenuhi hasrat orang Islam masih dalam keadaan yang rapuh dan penuh cabaran, namun kajian ini mengusulkan peripentingnya dialog antara peradaban dimana nilai-nilai universal manusia akan diperoleh dan dipegang oleh kedua-kedua pihak pembuat dasar iaitu  Islam dan bukan Islam. Di samping itu, umat Islam dan bukan Islam di Filipina perlu mengkaji dan mencontohi model keharmonian sosial Malaysia dan Singapura kerana kaitannya dengan kestabilan politik dan pertumbuhan ekonomi. Kata Kunci: Muslim di Filipina, institusi Islam, Islamisasi, intelektual Islam, Pembaharuan.


2018 ◽  
Vol 23 (1) ◽  
pp. 60-71
Author(s):  
Wigiyanti Masodah

Offering credit is the main activity of a Bank. There are some considerations when a bank offers credit, that includes Interest Rates, Inflation, and NPL. This study aims to find out the impact of Variable Interest Rates, Inflation variables and NPL variables on credit disbursed. The object in this study is state-owned banks. The method of analysis in this study uses multiple linear regression models. The results of the study have shown that Interest Rates and NPL gave some negative impacts on the given credit. Meanwhile, Inflation variable does not have a significant effect on credit given. Keywords: Interest Rate, Inflation, NPL, offered Credit.


2003 ◽  
Vol 48 (4) ◽  
pp. 139-146 ◽  
Author(s):  
B. Wett ◽  
J. Alex

A separate rejection water treatment appears as a high-tech unit process which might be recommendable only for specific cases of an upgrading of an existing wastewater treatment plant. It is not the issue of this paper to consider a specific separate treatment process itself but to investigate the influence of such a process on the overall plant performance. A plant-wide model has been applied as an innovative tool to evaluate effects of the implemented sidestream strategy on the mainstream treatment. The model has been developed in the SIMBA environment and combines acknowledged mathematical descriptions of the activated sludge process (ASM1) and the anaerobic mesophilic digestion (Siegrist model). The model's calibration and validation was based on data from 5 years of operating experience of a full-scale rejection water treatment. The impact on the total N-elimination efficiency is demonstrated by detailed nitrogen mass flow schemes including the interactions between the wastewater and the sludge lane. Additionally limiting conditions due to dynamic N-return loads are displayed by the model's state variables.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 878 ◽  
Author(s):  
Oliwia Pietrzak ◽  
Krystian Pietrzak

This paper focuses on effects of implementing zero-emission buses in public transport fleets in urban areas in the context of electromobility assumptions. It fills the literature gap in the area of research on the impact of the energy mix of a given country on the issues raised in this article. The main purpose of this paper is to identify and analyse economic effects of implementing zero-emission buses in public transport in cities. The research area was the city of Szczecin, Poland. The research study was completed using the following research methods: literature review, document analysis (legal acts and internal documents), case study, ratio analysis, and comparative analysis of selected variants (investment variant and base variant). The conducted research study has shown that economic benefits resulting from implementing zero-emission buses in an urban transport fleet are limited by the current energy mix structure of the given country. An unfavourable energy mix may lead to increased emissions of SO2 and CO2 resulting from operation of this kind of vehicle. Therefore, achieving full effects in the field of electromobility in the given country depends on taking concurrent actions in order to diversify the power generation sources, and in particular on increasing the share of Renewable Energy Sources (RES).


2021 ◽  
Vol 11 (9) ◽  
pp. 4136
Author(s):  
Rosario Pecora

Oleo-pneumatic landing gear is a complex mechanical system conceived to efficiently absorb and dissipate an aircraft’s kinetic energy at touchdown, thus reducing the impact load and acceleration transmitted to the airframe. Due to its significant influence on ground loads, this system is generally designed in parallel with the main structural components of the aircraft, such as the fuselage and wings. Robust numerical models for simulating landing gear impact dynamics are essential from the preliminary design stage in order to properly assess aircraft configuration and structural arrangements. Finite element (FE) analysis is a viable solution for supporting the design. However, regarding the oleo-pneumatic struts, FE-based simulation may become unpractical, since detailed models are required to obtain reliable results. Moreover, FE models could not be very versatile for accommodating the many design updates that usually occur at the beginning of the landing gear project or during the layout optimization process. In this work, a numerical method for simulating oleo-pneumatic landing gear drop dynamics is presented. To effectively support both the preliminary and advanced design of landing gear units, the proposed simulation approach rationally balances the level of sophistication of the adopted model with the need for accurate results. Although based on a formulation assuming only four state variables for the description of landing gear dynamics, the approach successfully accounts for all the relevant forces that arise during the drop and their influence on landing gear motion. A set of intercommunicating routines was implemented in MATLAB® environment to integrate the dynamic impact equations, starting from user-defined initial conditions and general parameters related to the geometric and structural configuration of the landing gear. The tool was then used to simulate a drop test of a reference landing gear, and the obtained results were successfully validated against available experimental data.


Author(s):  
Min-Guk Seo ◽  
Chang-Hun Lee ◽  
Tae-Hun Kim

A new design method for trajectory shaping guidance laws with the impact angle constraint is proposed in this study. The basic idea is that the multiplier introduced to combine the equations for the terminal constraints is used to shape a flight trajectory as desired. To this end, the general form of impact angle control guidance (IACG) is first derived as a function of an arbitrary constraint-combining multiplier using the optimal control. We reveal that the constraint-combining multiplier satisfying the kinematics can be expressed as a function of state variables. From this result, the constraint-combining multiplier to achieve a desired trajectory can be obtained. Accordingly, when the desired trajectory is designed to satisfy the terminal constraints, the proposed method directly can provide a closed form of IACG laws that can achieve the desired trajectory. The potential significance of the proposed result is that various trajectory shaping IACG laws that can cope with various guidance goals can be readily determined compared to existing approaches. In this study, several examples are shown to validate the proposed method. The results also indicate that previous IACG laws belong to the subset of the proposed result. Finally, the characteristics of the proposed guidance laws are analyzed through numerical simulations.


Author(s):  
Ana Guerberof Arenas ◽  
Joss Moorkens ◽  
Sharon O’Brien

AbstractThis paper presents results of the effect of different translation modalities on users when working with the Microsoft Word user interface. An experimental study was set up with 84 Japanese, German, Spanish, and English native speakers working with Microsoft Word in three modalities: the published translated version, a machine translated (MT) version (with unedited MT strings incorporated into the MS Word interface) and the published English version. An eye-tracker measured the cognitive load and usability according to the ISO/TR 16982 guidelines: i.e., effectiveness, efficiency, and satisfaction followed by retrospective think-aloud protocol. The results show that the users’ effectiveness (number of tasks completed) does not significantly differ due to the translation modality. However, their efficiency (time for task completion) and self-reported satisfaction are significantly higher when working with the released product as opposed to the unedited MT version, especially when participants are less experienced. The eye-tracking results show that users experience a higher cognitive load when working with MT and with the human-translated versions as opposed to the English original. The results suggest that language and translation modality play a significant role in the usability of software products whether users complete the given tasks or not and even if they are unaware that MT was used to translate the interface.


2021 ◽  
Vol 9 (7) ◽  
pp. 727
Author(s):  
José Fortes Lopes ◽  
Carina Lurdes Lopes ◽  
João Miguel Dias

Extreme weather events (EWEs) represent meteorological hazards for coastal lagoon hydrodynamics, of which intensity and frequency are increasing over the last decades as a consequence of climate changes. The imbalances they generated should affect primarily vulnerable low-lying areas while potentially disturbing the physical balances (salt and water temperature) and, therefore, the ecosystem equilibrium. This study arises from the need to assess the impact of EWEs on the Ria de Aveiro, a lagoon situated in the Portuguese coastal area. Furthermore, it was considered that those events occur under the frame of a future sea-level rise, as predicted by several climate change scenarios. Two EWEs scenarios, a dry and an extremely wet early summer reflecting past situations and likely to occur in the future, were considered to assess the departure from the system baseline functioning. It was used as a biogeochemistry model that simulates the hydrodynamics, as well as the baseline physical and biogeochemistry state variables. The dry summer scenario, corresponding to a significant reduction in the river’s inflow, evidences a shift of the system to a situation under oceanic dominance characterized by colder and saltier water (~18 °C; 34 PSU) than the baseline while lowering the concentration of the nutrients and reducing the phytoplankton population to a low-level limit. Under a wet summer scenario, the lagoon shifted to a brackish and warmer situation (~21 °C, <15 PSU) in a time scale of some tidal periods, driven by the combining effect of the tidal transport and the river’s inflow. Phytoplankton patterns respond to variability on local and short-term scales that reflect physical conditions within the lagoon, inducing nutrient-supported growth. Overall, the results indicate that EWEs generate local and transient changes in physical conditions (namely salinity and water temperature) in response to the characteristic variability of the lagoon’s hydrodynamics associated with a tidal-dominated system. Therefore, in addition to the potential impact of changing physical conditions on the ecosystem, saline intrusion along the lagoon or the transfer of brackish water to the mouth of the system are the main consequences of EWEs, while the main biogeochemistry changes tend to remain moderate.


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