bluuebunny/crossref_metadata_2025 huggingface dataset:
In situ temporal measurement of ultrashort laser pulses at full power during high-intensity laser–matter interactions
Authors: Crespo Helder M. , Witting Tobias , Canhota Miguel , Miranda Miguel , Tisch John W. G.
Published: July 2020

In laser–matter interaction experiments, it is of paramount importance to characterize the laser pulse on target (in situ) and at full power. This allows pulse optimization and meaningful comparison with theory, and it can shed fundamental new light on pulse distortions occurring in or on the target. Here we introduce and demonstrate a new technique based on dispersion-scan using the concurrent third harmonic emission from the target that permits the full (amplitude and phase), in situ, in-parallel characterization of ultrashort laser pulses in a gas or solid target over a very wide intensity range encompassing the

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regime of high harmonic generation and other important strong-field phenomena, with possible extension to relativistic intensities presently inaccessible to other diagnostics.
Sawlog quality and tree dimensions of Scots pine 34 years after artificial moose browsing damage
Authors: Matala Juho , Kilpeläinen Harri , Heräjärvi Henrik , Wall Tapio , Verkasalo Erkki
Published: July 2020

Moose ( L.) browsing causes severe damage in Scots pine ( L.) seedling stands. The effects of this damage on the quality of sawlogs were studied in a long-term controlled experiment. This article reports the stem size and external quality characteristics of Scots pine stems 34 years after artificial moose browsing damage. Damaging the trees by clipping the main stem at the seedling stage reduced the diameter, height, and tree volume of the trees at the end of the experiment. The tree growth reduction was dependent on the severity of clipping. The differences between the damaged and the control trees were more obvious in diameter than in height at the time of final felling. Stem form defects and vertical branches were the most typical externally detectable defects caused by clipping. Defects in the butt logs were detected in 71â89% of the damaged trees, depending on the clipping treatment severity. The stronger the clipping treatment, the more likely the stem form was defected and the more commonly were vertical branches and crooks detected in the stems. The results indicate that both tree dimensions and stem quality suffer from moose browsing. The findings of this controlled experiment more likely underestimate than overestimate the damage in comparison to real moose browsing. Further analyses are required to assess the effects of browsing damage on the internal quality of sawlogs and subsequent economic outcomes.Alces alcesPinus sylvestris
BETA CANTOR SERIES EXPANSION AND ADMISSIBLE SEQUENCES
Authors: Caalim Jonathan , Demegillo Shiela
Published: July 2020

We introduce a numeration system, called the beta Cantor series expansion, that generalizes the classical positive and negative beta expansions by allowing non-integer bases in the Q-Cantor series expansion. In particular, we show that for a fix $\gamma \in \mathbb{R}$ and a sequence $B=\{\beta_i\}$ of real number bases, every element of the interval $x \in [\gamma,\gamma+1)$ has a beta Cantor series expansion with respect to B where the digits are integers in some alphabet $\mathcal{A}(B)$. We give a criterion in determining whether an integer sequence is admissible when $B$ satisfies some condition. We provide a description of the reference strings, namely the expansion of $\gamma$ and $\gamma+1$, used in the admissibility criterion.
THE CONDENSATION OF WATER VAPOUR IN A MIXTURE CONTAINING A HIGH CONCENTRATION OF NON-CONDENSABLE GAS IN A VERTICAL TUBE
Authors: Havlík Jan , Dlouhý Tomáš , Krempaský Jakub
Published: July 2020

This paper deals with the condensation of water vapour possessing a content of noncondensable gas in vertical tubes. The condensation of pure steam on a vertical surface is introduced by the Nusselt condensation model. However, the condensation of water vapour in a mixture with non-condensable gas differs from pure vapour condensation and is a much more complex process. The differences for the condensation of water vapour in a mixture containing a high concentration were theoretically analysed and evaluated. In order to investigate these effects, an experimental stand was built. Experiments were carried out in regards to the case of pure steam condensation and the condensation of water vapour with a non-condensable gas mixture to evaluate the influence of the variable non-condensable gas content during the process. A non-condensable gas in a mixture with steam decreases the intensity of the condensation and the condensation heat transfer coefficient. A gradual reduction of the volume and partial pressure of steam in the mixture causes a decrease in the condensation temperature of steam, and the temperature difference between steam and cooling water. The increasing non-condensable gas concentration restrains the transportation of steam towards the tube wall and this has a significant effect on the decrease in the condensation rate.
NEURINGER-ROSEINWEIG MODEL BASED LONGITUDINALLY ROUGH POROUS CIRCULAR STEPPED PLATES IN THE EXISTENCE OF COUPLE STRESS
Authors: Vashi Yoginibahen Devendrasinh , Patel Rakesh Manilal , Deheri Gunamani Biswanath
Published: July 2020

This study intents to scrutinize the impact of ferrofluid in the presence of couple stress for longitudinally rough porous circular stepped plates. The influence of longitudinal surface roughness is developed using the stochastic model of Christensen and Tonder for nonzero mean, variance and skewness. Neuringer-Roseinweig model is adopted for the influence of ferrofluid. The couple stress effect is characterized by Stoke’s micro continuum theory. The modified Reynolds’ type equation is stochastically averaged and solved by no-slip boundary conditions. The closed form solutions for load bearing capacity and film pressure are obtained as a function of different parameters and plotted graphically. It is perceived that the load capacity gets elevated owing to the combined influence of magnetization and couple stress when the proper choice of roughness parameters (negatively skewed, standard deviation) is in place. Porosity and roughness (positively skewed) adversely affect bearing’s performance. The graphical and tabular analysis shows that there is a significant growth in load bearing capacity compared to the conventional lubricant case.
"A Sociedade de Instrução e Beneficência A Voz do Operário" Outra forma de fazer política: a propósito da reforma dos serviços escolares (1924-1935)
Authors: Bandeira Filomena
Published: July 2020

Este artigo insere-se num projeto sobre Escolas e experiências de referência em Portugal no século XX e centra-se no estudo de uma instituição que desenvolve atividades educativas num quadro associativo e para as classes populares. Optámos por uma apresentação descritiva com a intenção de argumentar que a adoção e aplicação de um modelo educativo, inspirado na Educação Nova e conformado a um público específico, assentou numa estratégia sociopolítica, emergente das condições históricas do associativismo operário na primeira metade do século XX e da situação vivida no País com a crise da Primeira República, que desembocou no Estado Novo. No artigo explanamos o processo de reforma dos serviços escolares da Voz do Operário entre 1924-1935, não sem antes apresentarmos uma história sumária da Sociedade, desde o fim do século XIX até à década de 1950, com o objetivo de representar a associação na sua dimensão, atividade e significado social.
ANÁLISE DA INSERÇÃO DA SAÚDE NOS ESTUDOS DE IMPACTO AMBIENTAL DOS LICENCIAMENTOS DAS BARRAGENS DE REJEITO DA SAMARCO, COMPLEXO DE GERMANO, MARIANA, MINAS GERAIS
Authors: Luz Mariana dos Santos Lima , Moutinho Flavio Fernando Batista
Published: July 2020

A mineração é uma atividade que necessita de licença ambiental para funcionar. Apesar da legislação vigente prever que aspectos de saúde sejam contemplados nos Estudos de Impacto Ambiental (EIA) no âmbito do licenciamento ambiental, isso ainda é muito incipiente. O presente artigo teve como objetivo analisar como os aspectos relacionados à saúde humana foram contemplados nos EIA referentes aos licenciamentos das barragens de rejeitos de mineração da empresa Samarco, Complexo de Germano, município de Mariana, estado de Minas Gerais, que passou por um grave desastre ambiental em 2015. Para tanto, foram analisados o EIA elaborado visando o licenciamento da barragem de rejeitos de minério de ferro de Fundão, rompida em 2015, e o EIA para instalação do sistema de contenção de rejeitos Alegria Sul, que veio substituir o anterior. Trata-se de uma pesquisa qualitativa de análise documental onde foi utilizada uma matriz de análise desenvolvida especificamente para esse fim. O estudo comparativo entre os dois EIA permitiu concluir que a inserção das questões de saúde nos dois estudos ofereceu resultados sobre a inserção da saúde similares e incipientes, com leve superioridade do EIA de Alegria Sul. A pesquisa ajudou a compreender as fragilidades que existem na participação do setor de saúde no licenciamento ambiental de barragens de rejeitos de mineração.
Lições da pandemia: aprender com outras epistemologias o cuidado coletivo com reciprocidade
Authors: Albuquerque Carla Pontes de , Fleuri Reinaldo Matias
Published: July 2020

Em tempos de pandemia, as fragilidades existentes decorrentes das desigualdades, conformadas e aprofundadas na globalização neoliberal, se expressam de forma mais contundente. O modelo biomédico, centrado na assistência hospitalar e em tecnologias duras, evidenciou sua insuficiência para o cuidado coletivo no contexto do Covid 19. O cuidado de vizinhança dos diferentes grupos populacionais e a Atenção Básica em Saúde integrada às redes de cuidado são vias que, se trilhadas, possibilitam um manejo mais adequado frente às situações emergenciais de saúde. Na trajetória de lutas e afetividades da Educação Popular na Saúde no Brasil, emergem práticas e saberes tecidos cotidianamente de forma compartilhada nas diversidades dos territórios de vida. Movimentos decoloniais na saúde, embora contra hegemônicos, têm apontado experiências mais plenas de cuidado coletivo, como o Bem Viver – cosmologia que adquire nuances entre povos originários na América Latina. São princípios elencados por essa perspectiva: reciprocidade, relacionalidade, complementariedade e solidariedade entre pessoas e comunidades. Aprender com outras epistemologias que trazem capilaridades de cuidado recíproco, incluindo todos os seres da Natureza, é uma possibilidade de potencializarmos outras narrativas para a promoção de saúde e para o adiamento do fim do mundo.
Educação Popular em Saúde
Authors: Cruz Pedro José Santos Carneiro , Silva Maria Rocineide Ferreira da , Pulga Vanderleia Laodete , Machado Aline Maria Batista , Brutscher Volmir José
Published: July 2020

No seio das iniciativas da área da saúde, a educação popular configura um trabalho social, no qual o agir é orientado pelo diálogo, no compartilhamento de conhecimentos comprometidos com a transformação social, assentada em utopias como direitos iguais para todos, emancipação humana, social e material. A cada dia, qualifica-se a produção teórica e prática provinda das experiências de Educação Popular em Saúde (EPS). Assim, vai se evidenciando um campo teórico como uma teoria do trabalho social em saúde; uma concepção alçada à epistemologia, possuidora de princípios éticos, teóricos e metodológicos. No presente ensaio, compartilharemos reflexões sobre a EPS, apontando provocações com o intuito de alimentar o debate e o pensamento autoavaliativo dos protagonistas dos movimentos e das práticas de EPS em todo o país ante os exigentes desafios da próxima década. Dentre os aspectos desenvolvidos, destacam-se: a centralidade da insistência na promoção e no aprimoramento da participação popular no agir cotidiano em saúde; a dimensão ética, política e epistemológica da EPS para o agir em saúde; a necessidade de transcender o metodologicismo; e a EPS diante do ultraliberalismo e do ultraconservadorismo na sociedade e nos espaços públicos
Qualidade da paisagem e perdas de solo frente à simulação de cenários ambientais no Cerrado, Brasil
Authors: Santos Arruda de Lim Gabriella a , Clementino Ferreira Nilson , Ferreira Manuel Eduardo
Published: July 2020

O presente estudo utilizou-se de fundamentos da ecologia, por meio da aplicação de algumas métricas espaciais, para verificar a atual fragmentação da paisagem na Região Metropolitana de Goiânia (RMG), com o objetivo de estabelecer áreas prioritárias para manutenção e para a recomposição florestal. Para tanto, foi realizada a simulação de três cenários, o primeiro representando a situação atual, o segundo considerando a recomposição florestal em Áreas de Proteção Permanente (APP) ao longo dos cursos d’água, enquanto no terceiro cenário, o reflorestamento nas regiões de alta e muito alta vulnerabilidade ambiental na área de estudo. A presente investigação também propôs avaliar a perda de solo por erosão laminar aplicado aos três cenários propostos para a região. Constatou-se que na RMG, de acordo com a atual configuração da paisagem, tem-se alta fragmentação dos remanescentes de vegetação, sendo a manutenção e conservação dos remanescentes fundamental, e o reflorestamento altamente recomendado. A espacialização desses resultados e indicação de áreas para reflorestamento e conservação servem de orientação às políticas públicas e na tomada de decisão coletiva envolvendo todos os municípios da RMG.
Issues Management of Islamic Political Parties to Election Campaign in 2019
Authors: Arenggoasih Wuri
Published: July 2020

In accordance with Article 29 of the 1945 Constitution of the Republic of Indonesia, Indonesia recognizes the religion and protects the freedom of the people in carrying out its religious teachings. Indonesia is a plural country because of the diversity of beliefs and the beliefs held by the community. But because of this diversity, Indonesia has a sensitivity especially associated with religious issues. In the last two years, the establishment of the negative issues about Islam has been increasing. Consequently, Islam is cornered in Indonesia. This situation is feared to be able to further exacerbate the potential for votes for the Islamic parties in the 2019 election. Therefore, the concept of issues management of Chase W. Howard model is used in this study to answer how the management of the Islamic party issues is to face the 2019 Election. The research method used is the qualitative descriptive approach in the interpretive paradigm with the design of case study research. The results of the research show that the Islamic party has exceeded all elements on the issues management of Chase model. These elements become the step of the Islamic party against the issues of Islam and exist in the democratic system, especially for the 2019 election without reducing the sense of peace in Indonesia.
Prohibition in Quran: Structure and Meaning
Authors: Idris Mardjoko
Published: July 2020

Quran is the word of Allah written in Arabic. In conveying its message, the Quran uses different sentences, including declarative, imperative, and interrogative sentences. This research will focus on prohibition sentences with analysis of speech acts. Prohibition sentence is a sentence that requires the termination of an act from the interlocutor, from the higher position to the lower one. It is assumed that besides being intended for conventional meanings, the prohibition sentences in the Quran also function as other meanings other than the original meaning, by previously understanding the context that becomes the background of a prohibition. The theory used is pragmatics, especially speech acts. The method used is the refer method and the recording technique. The research of prohibition sentences with pragmatics has obtained two prohibition tools those are sharîh and not sharîh. The prohibition sentences in the Quran are not only used for original meaning but also function as other meanings, such as for the purpose of prayer (do’a), offer (iltimâs), suggestion (irsyâd), continuous (dawâm), information as a result (bayânul 'âqibat), pessimistic (tayîs), threat (tahdîd), calming (i'tinâs), disfiguring (taubîh), and ignoring ('adamul-mubâlah).
Foundations of peace and harmony in families and communities: Insights from a TRUST, LEARN and CARE (TLC) framework
Authors: Hayes Alan , Freestone Margaret , Day Jamin
Published: July 2020

In a world riven by conflict, violent extremism and sectarian animosities, peace is in short supply. Promoting peace is, however, central to the great traditions of faith, including Islam. Contrary to their core precepts, fear, hatred and envy drive an evil mis-construal of the core tenets of these religions; the antithesis of their fundamental commitment to the promotion of tolerance, care and compassion.  Contemporary events defy comprehension and highlight the urgent need to find ways, especially within families and the communities in which they live, to counter radicalisation. Families, after all, ought to be key contexts for promoting dialogue, understanding and peace, consistent with the precepts of the Abrahamic religious traditions, and the Qur’anic focus on families that sees them as the forum for fulfilling the basic Islamic foundations of peace. Strong families build capable, caring and compassionate communities. The present paper briefly outlines a three-element model that might be usefully applied to better understand the processes of development of prosocial attitudes, beliefs and behaviours that are so vital for peaceful, constructive and compassionate co-existence; attributes that are so vitally needed in an increasingly multi-cultural, multi-ethnic and multi-faith world.  The elements are encapsulated in three conceptually linked acronyms: TRUST; LEARN; CARE or TLC. The trust, learn, care (TLC) framework has been developed from key principles in the new discipline of family studies. Global changes present many challenges for families and communities. This article concludes that a peaceful and harmonious future will be built on the foundations for dialogue and understanding that start in families and communities. Trust and tolerance, learning and teaching, caring and compassion are at the heart of acceptance of diversity, growth of understanding and promotion of respect for cultures, religions and beliefs.
The Correlation Analysis of Islamic Education (PAI) Learning Outcomes with Religious Tolerance at Universitas Pendidikan Indonesia (UPI)
Authors: Albana Hasan , Asyafah Abas , Rahmat Munawar
Published: July 2020

This study is motivated by the rampant cases and the spread of intolerant and radical understanding. The cases of intolerance and radicalization even occur to students who should possess a tolerant religious understanding and not get caught up in the indoctrination of religious violence. This study aims to analyze the correlation between PAI learning outcomes and religious tolerance. It applies a causal design and quantitative approach with survey method. The population of UPI Bumi Siliwangi is 24.340 students. The data is collected by utilizing probality sampling technique (cluster sampling). There are 344 respondents and questionnaires are served as the research instrument. Then, the data is analyzed by using descriptive and inferential analysis with the assistance of SPSS. The results of this study indicate that the learning outcomes of UPI students mostly get A is at the level of 45,9%. Religious tolerance of UPI students is generally at the most tolerant level of 61,63%. Tolerance to other religions is highest at the tolerant level of 60,17. Tolerance to the same religion but with different understanding, in this case is minority mazhab, is mostly tend to be intolerant level of 47,67%. Tolerance to the state and government, is mostly at the tolerant level of 38,66%. This study finds that there is no significant correlation between PAI learning outcomes and religious tolerance among the UPI students.
Correspondence Relationship between the Maximum Tensile Stress and Cycle Number during the Initial Stage of Low-Cycle Fatigue Test
Authors: Liu Ming , Ren Taolin , Gao Chenghui
Published: July 2020

The variation of the maximum tensile stress in each cycle with cycle number during the initial stage of low-cycle fatigue test before crack initiation was investigated based on the theoretically derived relation that is valid before crack initiates. The experimental data were fitted well by the proposed semiempirical expressions with four, three, or two fitting parameters, which were applicable to a large range of cycle numbers. The semiempirical expression with just one fitting parameter was only applicable to a small range of cycle numbers when the maximum tensile stress in each cycle did not fall below 85 % of the maximum one that appeared, which can be used as a guideline for the initial stage before crack initiation at low temperatures.
Mechanical characteristics evaluation of dual phase and related hardening techniques on AISI 4340 steel
Authors: Sharma Sathyashankara , Gurumurthy B. M , Kini U. Achutha , Hegde Ananda , Patil Ajinkya
Published: July 2020

Steel has wide range of applications and is used in various machinery and general metallic components. Depending on the particular application, steels with tailorable and appropriate properties are used. This requires various methods which can be used to alter the properties based on the requirements. Generally, mechanical properties of the steel are improved by conducting the heat treatment processes. The aim of the present work is to experimentally investigate the effects of conventional heat treatments and special hardening techniques for dual phase structure on mechanical properties of AISI 4340 steel. The test specimens are machined as per ASTM standards and hardness, tensile, impact and microstructure analysis were carried out after the heat treatment processes. Dual phase heat treatment to obtain ferrite-bainite structure is performed by heating the as-bought specimen to the intercritical temperature for two hours followed by isothermal holding in fusible salt bath containing sodium nitrate and sodium nitrite at subcritical temperature for 30 minutes and cooling in air to room temperature. Similarly, ferrite-martensite structure is obtained by air cooling after holding isothermally in the salt bath for 10 seconds.  Ferrite-bainite steel was observed to be soft, whereas ferrite-martensite steel was relatively harder. Austempered steel has high toughness with optimum hardness and conventionally hardened steel is the hardest among all. Microstructure shows colony of bainite and martensite in ferrite matrix of ferrite-bainite and ferrite-martensite dual phase structures respectively. An increase in brittleness was observed with the increase in hardness due to the conventional hardening to display lesser impact strength compared to austempered steel.
Regeneration of geothermal-sludge based sodium silicate catalyst for transesterification of palm oil with methanol
Authors: Perdana I. , Lenny Lenny , Bendiyasa I. M.
Published: July 2020

Sodium silicate synthesized from geothermal sludge of a geothermal power plant in Indonesia was applied as a solid catalyst to catalyze transesterification reaction of palm oil with methanol. In our previous study, it has been found that the catalyst deactivated due to hydrocarbon contamination on its surface. In the present work, 3 (three) different regeneration methods were studied for reactivation of the catalyst. The studied methods were: 1) calcination at 400oC for 3 hours with a ramp of 20°C/minutes, 2) 1x-washing with methanol at room temperature, and 3) 3x-washing with methanol at 60°C. The performance of the catalyst was studied by sequential reaction batches to monitor the reaction yield from time to time. The sequence consisted of 4 (four) transesterification reaction cycles, with a catalyst regeneration process before reused in subsequence cycle. Experimental results showed that although none of the regeneration processes regained catalyst activity as high as that of the freshly-activated catalyst, the third regeneration method, i.e. 3x-washing with methanol at 60°C regained higher catalyst activity compared to the other two studied methods. The method could maintain the reaction conversion at about 50% after four cycles of reaction and regeneration, Furthermore, the kinetics of the catalytic transesterification reaction was studied by fitting the experimental data with calculated yield obtained from mathematical modelling. It was found that among the first, second, and third order reaction kinetics, the experimental data was best fitted by the calculated results from the first order reaction kinetics. Results from this work suggested that even though 3x-washing regeneration of sodium silicate catalyst with methanol at 60°C offered relatively high reactivation, further study for improvement is still needed.
Design and construction of a strain gauge-based dynamometer for a 3-axis cutting force measurement in turning process
Authors: Rizal M. , Ghani J. A. , . Husni , . Husaini
Published: July 2020

The cutting force is the most significant information in machining processes for the cutting parameter and tool geometry optimization, machine tool design, machinability testing of new materials and tool condition monitoring systems. This paper develops a strain gauge-based dynamometer for a 3-axis cutting force measurement in turning process. The octagonal rings are utilized as force transducer to develop strain gauge-based dynamometer to measure the cutting force acting on the tip of the tool. A novel geometrical design of the dynamometer structure allowed the standard tool shank of the turning operation to be easily changed without altering the sensor system. The developed dynamometer can perform the cutting force measurement up to 2.9 kN and has a dynamic response of about 766 Hz. The sensitivities were found approximately in the range of 31.3x10-3 – 172.4x10-3 mV/N and it has a low cross-sensitivity error of below 0.87%. This paper is focus on geometrical design, mathematical and FEM analyses which are significant role in force sensor developed and present an application of low cost sensing method in turning process.
An experimental study of solar thermal system with storage for domestic applications
Authors: Abid M. , Yousef B. A. A. , Assad M. E. , Hepbasli A. , Saeed K.
Published: July 2020

Building sector consumes a greater portion of energy for heating and cooling applications. The utilization of fossil fuels for space and water heating in buildings cause a negative effect on the environment by producing larger CO2. In this study solar thermal water heating system for building application have been analyzed from the first and second law perspectives of thermodynamics considering various scenarios and water consumption pattern. The solar flat collector is very commonly used to extract energy from sunlight. Therefor energy and exergy efficiency curves for the solar flat collector were presented. The energetic and exergetic values for the system were calculated based on the experimental values for the overall system, the heat exchanger and the pumps using the approach of exergetic product/fuel basis. The greatest and lowest relative irreversibility’s occurred at the solar collector and the heat exchanger with values of 85.73% and 2.45%, respectively, and the system overall exergy efficiency was determined to be 20.28%. The energy and exergy efficiencies of the solar collector were analyzed at three different cases depending on the mass flow rates in the solar collector and the secondary circuit of the system. Three different mass flow rates were applied to the inlet of the secondary circuit to observe the efficiency effect on the solar collector circuit. This study can assist in selecting a proper solar collector and storage size for buildings of various capacity and possible improvement in the design of the system components.
Real-time implementation of an enhanced nonlinear PID controller based on harmony search for one-stage servomechanism system
Authors: Shamseldin Mohamed. A. , Sallam Mohamed , Bassiuny A. M. , Abdel Ghany A. M.
Published: July 2020

This paper presents a real-time implementation of an enhanced nonlinear PID (NPID) controller to follow a preselected position profile of one stage servomechanism drive system. This purpose should be realized regardless the different operating points and external disorders (friction and backlash). In this study, the MATLAB Simulink used for purpose of controller design while the result from simulation will be executed in real time using LABVIEW software. There is not enough information about the servomechanism experimental setup so, the system identification techniques will be used via collecting experimental input/output data. The optimum parameters for the controllers have been obtained via harmony search optimization technique according to an effective cost function. Also, the performance of enhanced NPID controller has been investigated by comparing it with linear PID controller.  The experimental and simulation results show that the proposed NPID controller has minimum rise time and settling time through constant position reference test. Also, the NPID control is faster than the linear PID control by 40% in case of variable position reference test.
Numerical simulation of two-phase separation in T-junction with experimental validation
Authors: Tran Minh , Memon Zeeshan , Saieed Ahmed , Pao William , Hashim Fakhruldin
Published: July 2020

Liquid carryover in T-junction due to splitting nature of two-phase flow causes serious issues for downstream equipment which is not designed to handle excessive liquid. In this paper, the phenomena of liquid carryover in T-junctions were analyzed using the Volume of Fraction (VOF) together with the k-ε turbulence model. T-junction separation efficiency was measured through mass flow rate fraction of air and water between the branch and main arm over a range of diameter ratios 0.6 to 1.0, water superficial velocity 0.186 to 0.558 m/s and air superficial velocity 4 to 8 m/s. The results showed simulation model was successfully validated with average deviation of less than 5% and can be used to predict phase split of slug flow in T-junction. The numerical model confirmed the significant influence of diameter ratio and superficial velocities of air and water on phase split. Reduced T-junction delivers better separation performance compared to regular T-junction. In slug flow regime, T-junction’s performance can be improved by either decreasing air velocity or increasing water velocity. A new dimensionless parameter, namely the area under the curve of separation efficiency (S), was proposed and proved as a qualified judging criteria for evaluating phase separation efficiency of T-junctions.
Three dimensional cyclonic turbulent flow structures at various geometries, inlet-outlet orientations and operating conditions
Authors: Pasymi Pasymi , Budhi Y. W. , Irawan A. , Bindar Y.
Published: July 2020

Flow structure inside a chamber greatly determines the process performances. Therefore, the flow structure inside a chamber are often constructed in such a way as an effort to obtain equipment performances in accordance with the expectations. This study explored flow structure inside several chamber geometries and operating conditions. Three types of chamber, namely; GTC, DTC and TJC were set as the investigated chambers. The Computational Fluid Dynamics technique, supported by some experimental data from the literature, is used as an investigation method. The RANS based models, under Ansys-Fluent software were used in this numerical investigation. Simulation results revealed that the flow structures of GTC and DTC are predominantly created by spiral and vortex patterns. The vortex stabilizer diameter in the GTC affects the vortex pattern, velocity profile and pressure drop. The flow structure of DTC presents the most complex behavior. The flow structure inside TJC, in the case of unconfined outlet boundary, is characterized by the helical and wavy jet pattern. This structure is determined by the initial tangential intensity (IIT) and the inlet aspect ratio (RIA). The structures of vortex, helical, and wavy axial flow are properly constructed and visualized in this paper. There is no a turbulence model which is always superior to the other models, consistently. The standard k-ε model exhibits the realistic and robust performances among  all of investigatied cases.
Effects of heat energy on morphology and properties of selective inhibition sintered high density polyethylene
Authors: Rajamani D. , Balasubramanian E
Published: July 2020

This study provides an account of comprehensive experimentation and mechanical characterisation of high density polyethylene (HDPE) parts that are fabricated through an additive manufacturing process called selective inhibition sintering (SIS). In this study, test specimens are fabricated by selective fusing of HDPE particles through controlled heating. Morphological studies and mechanical property evaluation of these specimens are carried out to assess the impact of energy on sintering of HDPE particles and structural integrity. Results indicate that, heat energy up to a threshold level of 28.48 J/mm2 results in superior fusion of the HDPE particles, and further increase causes degradation of the structure. Surface roughness, tensile and flexural properties of SIS parts are compared with those of injection moulded parts for assessing their suitability to engineering applications.
Drag reduction by combination of flow control using inlet disturbance body and plasma actuator on cylinder model
Authors: . Budiarso , . Harinaldi , Kosasih E. A. , Karim R. F. , Julian J.
Published: July 2020

Flow past a cylinder is one of the things that is very applicable in everyday life. But behind those facts, there is a problem in it namely the drag force which is adverse and needs to be reduced. This research was conducted to find solutions to reduce drag by using a mix of passive flow control of inlet disturbance body and active flow control from plasma actuators. This research uses a test model in the form of a cylinder of a diameter of 120 mm with Reynolds Number 15000, 41000, 62000 and was expected to reduce drag after a given combination of flow control. From the results shown, either inlet disturbance of body and plasma actuators as well as a combination of both the flow of control is capable of performing the reduction coefficient of drag up to 70,22% on a variation of the Reynolds Number 62000.
Application of low transformation-temperature filler to reduce the residual stresses in welded component
Authors: Azizpour K. , Moshayedi H. , Sattari-far I.
Published: July 2020

Tensile residual stress is a major issue in integrity of the welded structures. Undesirable tensile residual stress in welding may reduce fracture toughness and fatigue life of welded structures. The low transformation-temperature (LTT) fillers, due to introducing compressive residual stresses caused by prior martensitic transformation, can reduce tensile residual stresses in the weld zone. The effects of using LTT fillers on welding residual stresses of high strength steel sheets are studied and compared with conventional fillers. 3D finite element simulations including coupled thermal-metallurgical-mechanical analyses are developed using SYSWELD software to predict the welding residual stresses. For validation of the finite element model, the residual stresses are measured through hole drilling strain gage method. The results indicate that using the LTT fillers cause a decrease of the longitudinal tensile residual stresses of the weld metal from 554 MPa to 216 MPa in comparison with conventional fillers. The transverse residual stresses of the weld line are changed from tensile 156 MPa to compressive 289 MPa with using LTT fillers instead of conventional fillers.
Investigations on mechanical and wear behavior of nano Al2O3 particulates reinforced AA7475 alloy composites
Authors: Nagaral Madeva , Auradi V. , Kori S. A. , Hiremath Vijaykumar
Published: July 2020

In the present investigation synthesis, microstructure, mechanical and wear behavior of 5 weight percentage of nano Al2O3 particulate reinforced AA7475 alloy composites has been reported. AA7475 matrix composite containing nano Al2O3 were fabricated by conventional stir casting method. The microstructures of the composites were examined by scanning electron microscopy. Further, mechanical and wear behavior of as cast AA7475 alloy and AA7475 - 5 wt. % nano Al2O3 composites were studied. Mechanical properties like hardness, ultimate, yield strength and percentage elongation were evaluated as per ASTM standards. Pin on disc apparatus was used to conduct the dry sliding wear tests. The experiments were conducted by varying loads and constant sliding speed of 300rpm for sliding distance of 4000m. Microstructural observation revealed the uniform distribution of particles in the AA7475 alloy matrix. From the analysis, it was found that the hardness, ultimate tensile strength and yield strength of composites were increased due to addition of nano Al2O3 particle in the AA7475 alloy matrix. Percentage elongation of the composite decreased in 5 wt. % nano Al2O3 reinforced composites. Further, the volumetric wear loss was found to increase with the load and sliding distance for all materials. Worn surface analysis made by using scanning electron micrographs to know the various mechanisms involved in the wear process.
The effect of surface roughness of the impeller to the performance of pump as turbine pico power plant
Authors: Zariatin D. L. , Rahmalina Dwi , Prasetyo Eko , Suwandi A. , Sumardi M.
Published: July 2020

Pump as Turbine (PAT) is one of a hydropower plant that applies a pump with a reversed flow, working as a turbine to generate electrical power. It has the advantages of low-cost, widely available in the market and user-friendly. However, like other hydropower plants, PAT technology has low performance in term of power output. The impeller surface roughness is one of critical aspect, which influences PAT performance because poor surface roughness causes losses and cavitation. The objective of the research is to increase the PAT performance by improving the quality of the surface roughness and validate by the experimental tests. A low-cost and customize hand grinding process was applied to produce five impellers with three different levels of surface roughness (average surface roughness of 0.16 mm, 0.24 mm, and 0.40 mm), an edge rounded impeller, and a varnish lacquer coated impeller. All of the impellers undergo performance testing. The performance of the original impeller (without modification) used as a comparison. The experiment result shows that an impeller with a lower surface roughness (lower Ra number) has a higher performance. An impeller with an average surface roughness of 0.16 mm improved 10.9% of its initial performance. Additional edge rounding for a 0.16 mm surface roughness impeller would improve its performance by 13.1%.  The optimum turbine efficiency of 15.45% was achieve-able by implementing an impeller with the lowest surface roughness.
Evaluation of the chemical and thermo-physical properties of locally aggregated kaolin-based refractory materials
Authors: Olalere A. A. , Yaru S. S. , Dahunsi O. A.
Published: July 2020

There is a continuous demand for refractory materials to meet the increasing expansion of industries and plants. Local clay materials are being explored to augment the inadequate supply of refractory materials. This study therefore evaluated the suitability of locally aggregated kaolin as refractory material. The kaolin was aggregated from Ipinsa kaolin, termite hill materials and bentonite in the ratio 5:4:1 by mass. Chemical analysis carried out on the materials using Proton Induced X-ray Emission (PIXE) Equipment revealed that the kaolin aggregate had a composition of 37.22% alumina (Al2O3) and 51.93% silica (SiO2). The Ipinsa kaolin comprised Al2O3 at 43.05% and SiO2 53.91%, termite hill material (Al2O3 22.69%, SiO2 58.83%) and bentonite had 23.10% Al2O3 and 55.40% SiO2. It shows that Ipinsa kaolin can be used for refractory materials in furnaces, kilns and stoves while the aggregated clay can be used in applications requiring more superior refractory properties.  The thermo-physical analysis of the aggregated clay revealed a bulk density of 1.84 g/cm3, apparent porosity 31.54%, linear shrinkage 4.00%, thermal shock resistance 40+ and refactoriness 1900 oC. The refractoriness indicated that the aggregated clay is also suitable for use as ceramic fibre within the temperature range of 1800 and 2000 oC.
Compare the forecasting method of artificial neural network and support vector regression model to measure the bullwhip effect in supply chain
Authors: Fradinata E. , Suthummanon S. , Suntiamorntut W. , Mat Noor Muhamad
Published: July 2020

The objective of this study was to compare the Bullwhip Effect (BWE) in the supply chain through two methods and to determine the inventory policy for the uncertainty demand. It would be useful to determine the best forecasting method to predict the certain condition. The two methods are Artificial Neural Network (ANN) and Support Vector Regression (SVR), which would be applied in this study. The data was obtained from the instant noodle dataset where it was in random normal distribution. The forecasting demands signal have Mean Squared Error (MSE) where it is used to measure the bullwhip effect in the supply chain member. The magnification of order among the member of the supply chain would influence the inventory. It is quite important to understand forecasting techniques and the bullwhip effect for the warehouse manager to manage the inventory in the warehouse, especially in probabilistic demand of the customer. This process determines the appropriate inventory policy for the retailer. The result from this study shows that ANN and SVR have the variance of 0.00491 and 0.07703, the MSE was 1.55e-6 and 1.53e-2, and the total BWE was 95.61 and 1237.19 respectively. It concluded that the ANN has a smaller variance than SVR, therefore, the ANN has a better performance than SVR, and the ANN has smaller BWE than SVR. At last, the inventory policy was determined with the continuous review policy for the uncertainty demand in the supply chain member.
Role of nanoadditive blended biodiesel emulsion fuel on the performance and emission characteristics of diesel engine
Authors: Rajesh Kumar S. , Sai Chaitanya P.
Published: July 2020

An investigational research is carried out to found the performance and emission characteristics of a direct injection (DI) diesel engine with aluminium oxide nanoparticle additives in water and biodiesel blend. Palm methyl ester was produced by transesterification and blended with water. Aluminium oxide nanoparticles of 50 and 100 ppm in proportion are subjected to high-speed mechanical agitation followed by ultrasonication. The experimentations were conducted on a single cylinder DI diesel engine at a constant speed of 1500 rpm using different aluminium-oxide (AL2O3)-blended with emulsified biodiesel (PBD5%W+100ppm, PBD10%W+50ppm, PBD15%W+100ppm, PBD20%W+50ppm) and the outcomes were compared with those of neat diesel and Palm biodiesel. The experimental results indicated that brake thermal efficiency of PBD20%W+50 ppm and PBD+15%W+100ppm aluminium oxide was increased by 3-4% with 1.72% betterment in specific fuel consumption. Emissions of nitrogen oxide and hydrocarbon were reasonably lower than diesel fuel.
Multiaxial fatigue analysis for the shaft of a 100 MW hydro-power generator
Authors: Mantilla C. A. , Valdés J. A. , Casanova F.
Published: July 2020

This paper presents a stress and fatigue life analysis for the shaft of a 100  hydro-generator. Normal and shear stresses were measured at the cylindrical section of the shaft at several power levels. A finite element model was developed to find points with stress concentration and the corresponding stress concentration factor. Analytical models taken from the literature were implemented to calculate stresses during phase-to-ground and phase-to-phase failure. Stresses were linked with the generation history of the machine taken each hour during one year to obtain the stress history. With the stress history, the Wang-Brown multiaxial fatigue model and the Miner’s rule were used to estimate the fatigue life.

Stresses on the shaft were found to be dependent on the generated power. Operation at partial load (between 30 and 60% of full load) was found to produce higher vibration in comparison with operation at power greater than 60% of full load. Changing the power level produced higher damage than the vibration produced during operation at a steady state condition. It was found that the shaft has a practically infinite life even when the damage produced during electrical failure was considered.
Alternative scheme for frequency response function measurement of experimental-analytical dynamic substructuring
Authors: Wan Iskandar Mirza W. I. I. , Abdul Rani M. N. , Yunus M. A. , Omar R. , Mohd Zin M. S.
Published: July 2020

The accuracy of the predicted dynamic behaviour of an assembled structure using the frequency based substructuring (FBS) method is often found to be diverged from the experimental counterparts. The divergence which has become the paramount concern and major issue for   structural dynamicists is because of the unreliable experimental FRF data of the interfaces of substructures, arising from the limited resources of appropriate excitation points and accelerometer attachments in the vicinity of the interfaces. This paper presents an alternative scheme for FRF measurement of the experimental FRF data of substructures. In this study, an assembled structure consisting of two substructures were used, namely substructure A (Finite element model) and substructure B (Experimental model). The FE model of substructure A was constructed by using 3D elements and the FRFs were derived via the FRF synthesis method. Specially customised bolts were used to allow the attachment of accelerometers and excitation to be made at the interfaces of substructure B, and the FRFs were measured by using impact testing. Both substructures A and B were then coupled by using the FBS method and the coupled FRF was validated with the measured FRF counterparts. This work revealed that the proposed scheme with specially customized bolts has led to a significant enhancement and improvement in the FBS predicted results.
Effect of copper based filler composition on the strength of brazed joint
Authors: Sulaiman H. A. J. , W. M. N. Hissyam W. N. , M. H. Aiman , Ishak M. , Ariga T.
Published: July 2020

Vacuum brazing of copper-based filler was performed using pure copper plate as its based metal. The brazed joint was obtained at different temperatures, 680oC and 730oC, with same holding time, which is 30 minutes. MBF 2005 (Cu, 5.7wt.%Ni, 9.7wt.%Sn, 7.0wt.%P), MBF 2002 (Cu, 9.9wt.%Ni, 4.0wt.%Sn, 7.8wt.%P) and VZ 2250 (Cu, 7.0wt.%Ni, 9.3wt.%Sn, 6.3wt.%P) alloys were used as brazing filler materials. The intermetallic compound (IMC) and mechanical properties of the joints were investigated in detail. The result show that the interfacial microstructure of the brazed joints is Cu3P and (CuNi)2P. As the brazing temperature increase from 680oC to 730oC, the IMC become thicker leading to decrease in joining strength due to brittle IMC formation. The maximum shear strength reached 112 MPa at 680oC for MBF 2002 and 129 MPa at 730oC for MBF 2005. Hence, it is found that the composition of filler effects the strength of brazed joint.