bluuebunny/crossref_metadata_2025 huggingface dataset:
Individual Incremental loading factor based maximum loadability limit prediction using modern optimization tools
Authors:   Dept of Electrical and Electronics Engineering. K.L.N College of Engineering, India, S Manohaaran , K Gnanambal ,   Dept of Electrical and Electronics Engineering. K.L.N College of Engineering, India
Published: November 2021

Infrastructure innovation in the power system industry encourages more partakers to participate in the electricity market which improvises the load utilization level. So, the maintenance of power system’s agility with respect to any dynamic update in terms of load level is necessary. Precise prediction of maximum allowable loading point helps to enhance the power system agility and also improvises the total allowable power transfer capability which in turn helps to supply continuous eminent power supply at the minimal cost to the customers by means of encouraging more contracts. Considering the above potential benefits, in this papear by using individual incremental loading factor (IILF) the precise prediction of total loadability limit (TLL) of the system is manipulated with the help of newly evolved meta-heuristic optimization algorithm such as Grey Wolf (GRW) optimizer and Flower Pollination Algorithm (FPA). The allowable single line contingency scenario is considering along with base case scenario to extract the more realistic TLL which helps to maintain the power system balance with respect to the dynamic nature of the load. The proposed maximum loading point extraction manipulation solution problem is tested with the help of three standard IEEE systems such as 30 Bus, 57 Bus and 118 bus systems. The extracted test results show that the predicted maximum allowable loading point enhances the load utilization level without affecting the system securities. The statistical performance measures of GRW and FPA confirmed the better balance of exploration and exploitation in extracting the optimal results.
Performance of quadrilateral perforated prestressed concrete rafters
Authors:   Engineer, Directorate of AL-Naser Municipality, Directorate of Thi-Qar Municipalities, Thi-Qar Government, Iraq, F. Izzet Amer , K. Oukaili Nazar ,   Engineer, Directorate of AL-Naser Municipality, Directorate of Thi-Qar Municipalities, Thi-Qar Government, Iraq, J. Alkhafaji Falah ,   Engineer, Directorate of AL-Naser Municipality, Directorate of Thi-Qar Municipalities, Thi-Qar Government, Iraq
Published: November 2021

This study focuses on the behavior of simply supported perforated prestressed concrete rafters (PPCRs) under single midspan monotonic static loading. The experimental program consisted of testing seven specimens; one solid (control) rafter, and six perforated with quadrilateral openings. The main investigated variables are the number and height of the openings. The test findings indicate that, in comparison to the solid rafter, the presence of quadrilateral openings in the PPCRs led to reducing the load capacity by (4.3-36%) and increase the midspan deflection at ultimate by (14.8-33%). Also, increasing the number of concrete posts between openings resulted in increasing the failure load and decreasing the deflection at all stages of performance of the prestressed concrete rafter. On the other hand, decreasing the depth of the upper and lower chords by 25% for PPCRs with the same number of openings led to a reduction in the failure load by (36, 29.5, and 24.5%) for rafters with 6, 8, and 10 openings, respectively.
Multiple factor comprehensive analysis (CAMF) model of occupational health and safety training effect for construction workers
Authors:   School of accounting, Wuhan Qingchuan University, Wuhan 430204, Hubei, P.R.China, Associate Professor, Ph.D, Cao Zhonghong , Chen Tao ,   Wuhan University of Science and Technology, Wuhan 430081, Hubei, P.R.China, Cao Yuqing ,   Huazhong University of Science and Technology, Wuhan 430074, Hubei, P.R.China, 1249053233@qq.com
Published: November 2021

In view of the occupational health and safety (OHS) training on the safety of construction workers, and many complex factors. Through empirical investigation, this study proposes a set of multiple factor comprehensive analysis (CAMF) model to explore the effectiveness of OHS training and its main influencing factors. It has been found that training effectiveness is positively related to whether to receive OHS training or not and also positively related to training methods. It has also been found that the effectiveness of training is positively related to the importance of post responsibility. The results show that the construction industry needs to strengthen the OHS system training of grass-root workers, and the training should be classified and graded according to the workers' educational backgrounds, training methods, job satisfaction, and job responsibilities. In the safety training management of on-site workers, salary is the basic factor, and more attention should be paid to the factors such as workers' physical safety, training and learning, and future career development. The empirical results show that CAMF model has certain practical significance. The research results can provide paths and suggestions for improving the effectiveness of OHS training in China's construction industry, and provide some reference for other developing countries to carry out OHS training.
Deformation and Mechanical behavior of the Drill Pipe during Subsea Production Tree Installation
Authors:   School of Mechatronic Engineering, Southwest Petroleum University, Chengdu, China, Wang Fei
Published: November 2021

The article presents an analytical model to study the deformation and mechanical behavior of the drill pipe during subsea production tree (SPT) installation. Lateral and axial loads were considered, including the ocean wave, ocean current, drill pipe size and SPT weight that might dominant the deformation and mechanical behavior of the pipe. And the finite difference method and Gauss-Jordan elimination method were used to solve the established nonlinear analysis model. The results indicate that the ocean current, water depth and drill pipe size are the main factors affecting the lateral displacement of the last node of drill pipe and mechanical behavior of the pipe at lift-off point and thus need to be considered when designing such installation process.
Flow simulation for a horizontal well with slotted screen and ICD completions based on the wellbore–annulus–reservoir model
Authors:   Petroleum Engineering Institute of Yangtze University, Wuhan, Hubei, 430100, China, Luo Wei , Liao Ruiquan ,   *Petroleum Engineering Institute of Yangtze University, Wuhan, Hubei, 430100, China, Wang Jing ,   Research and Development Center, Tuha Oil Field Company, PetroChina, Hami, Xinjiang 839009, China, Wang Hongying ,   Research and Development Center, Tuha Oil Field Company, PetroChina, Hami, Xinjiang 839009, China, Liu Zilong ,   Petroleum Engineering Institute of Yangtze University, Wuhan, Hubei, 430100, China, Cheng Yang ,   Petroleum Engineering Institute of Yangtze University, Wuhan, Hubei, 430100, China
Published: November 2021

A flow is observed in the pipe for the horizontal section of slotted screen completion and inflow control device (ICD) completion, and an annulus flow exists between the pipe and the borehole wall. Based on the principles of mass conservation and momentum conservation, a model for variable mass flow in an oil reservoir to simulate wellbore–annulus–reservoir state in the horizontal section of slotted screen completion and ICD completion is proposed. Consequently, based on the newly established formation transient seepage model and wellbore and annulus variable mass flow model, an accurate prediction of the production rate of a horizontal well as well as optimized design parameters for slotted screen completion and inflow control device (ICD) completion are achieved. The predicted flow profiles of the established model are confirmed using the simulation software from Computer Modeling Group Ltd. When external casing packers are not considered, findings show that the predicted production rates of both slotted screen completion and ICD completion, which are obtained using the variable mass flow models without annulus flow modeling, are higher than the rates obtained using the variable mass flow models with annulus flow modeling. Both models show that the pressure profile and flow profile of the borehole wall are more uniform in wellbore–annulus–reservoir in horizontal wells. The flow model for horizontal wells with annulus flow modeling should be established to improve the accuracy of the predicted production.
Evaluating and Managing MSDs in Domestic Tasks through Ergonomics.
Authors:   Department of Industrial and Manufacturing and Engineering, NED University of Engineering & Technology, Karachi, Pakistan., Zaheer Asim , Fatima Anis ,   Department of Industrial and Manufacturing and Engineering, NED University of Engineering & Technology, Karachi, Pakistan., Rowson Jennifer ,   Department of Mechanical Engineering, The University of Sheffield, Sheffield, S1 3JD, UK
Published: November 2021

An increasing number of elderly people in recent years have raised the issue of disability/dependency. The common cause of disability/dependency in elderly people is musculoskeletal pain and related indications (Urwin, Symmons et al. 1998). Therefore, Musculoskeletal disorders (MSDs) has become worldwide dilemma (Sanders 1997). The risk of MSDs occurs both within and outside the work environment where it is being performed (Hedge, Rudakewych et al. 2002). If MSDs risk is identified at an early stage of life, then it might help people to manage the MSDs risks in performing daily tasks before it can interfere in their life and make them dependent on others. Also early management of person’s own risk can help the healthcare professionals to helps people in the society to maintain their independence in later life and reduced the social care cost burden on community. The main objective of this study is to address the known statement that there is an increased risk in later life of injury which is associated with loss of independence. Therefore, this study evaluates a person’s risk of having MSDs through performing domestic tasks. And thus with a greater understanding of that risk put in place an assessment methodology with the aim of increasing independence by decreasing or managing risks related to bad postures associated with the performance of domestic tasks. A survey was conducted to identify the hardest tasks, to be performed in home environment. A newly developed tool called “task assessment tool for ease and risk (TAER)”(Zaheer, Yoxall et al. 2018) is used to identify associated risk involved. Survey result showed that top three main task, numerous people struggle with, are general housekeeping (mopping), laundry and food cooking. It was found that TEAR analysed results were in accordance with the survey results. It is concluded from the study that, TEAR analysed results were in accordance with the survey results and people were struggling with three main task, that are general housekeeping (mopping), laundry and food cooking. Also, TAER can easily distinguish between those tasks which help the individual to take heed of the way in which he or she is performing the tasks. Also conclude that, if this tool (TAER) provide to general people in the community through healthcare services, will enable people to know their risks in performing domestic tasks and maintain their independence by acting upon the recommendation provided, which results in decrease in the likelihood of disability/dependency and stay in their own home as long as possible.
Reduction of Emission Gas Concentration from Coal Based Thermal Power Plant using Full Combustion and Partial Oxidation System
Authors:   Department of Mechanical Engineering, Bannari Amman Institute of Technology, Sathyamangalam-638401, Tamilnadu, India, B Kalidasan , K Deepika ,   Department of Biotechnology, Bannari Amman Institute of Technology, Sathyamangalam-638401, Tamilnadu, India, R Shankar ,   Energias De Renovables, UNAM, Temexico, Mexico, A K Pandey ,   Research Centre for Nano-Materials and Energy Technology (RCNMET), School of Science and Technology, Sunway University, No. 5, JalanUniversiti, Bandar Sunway, Petaling Jaya, 47500 Selangor Darul Ehsan, Malaysia, Shahabuddin Syed ,   Department of Science, School of Technology, Pandit Deendayal Petroleum University, Knowledge Corridor, Raisan Village, Gandhinagar-382007 Gujarat, India, Kothari Richa ,   Department of Environmental Sciences, Central University of Jammu, Samba-18001, Jammu & Kashmir, India., Agarwal Priyank ,   Energy Division, Mechanical Engineering, VIT University, Vellore-632014, Tamilnadu, India, Sharma Kamal ,   Department of Mechanical Engineering, Institute of Engineering and Technology, GLA University, Mathura, 281406, India
Published: November 2021

Rapid growth in industrialization has led to high dependency of reliable electric power source for its operation. On the contrary, thermal power plants expel pollutants consisting of hazardous gases that result in degradation of environment and ecosystem. Thus, utmost importance is to generate clean and efficient energy from power plant. This current article resolves the problem of sustainable power production using coal-based thermal power plants, by integrating gasification technologies to the system. The performance of thermal power plant in terms of emission is numerically analyzed with varying gasifier pressure, air-fuel ratio, steam-fuel ratio and flue gas-fuel ratio. Numerical simulation of the gasification cycle with varying parameters is carried out using MATLAB. Optimum performance at gasifier pressure of 2 bar and the steam-fuel ratio of 0.25 was observed with relative air-fuel of 0.075. With increasing flue gas-fuel ratio from 0.25 to 1.00, although the mole fractions of components of syngas don’t differ much, the heating value and cold-gas efficiency of syngas produced decreases for each fuel. Considering the emissions, simulated results present co-gasification as better option over conventional systems. A reduction of two-third in kg of CO2 released per kg of fuel was observed with almost three-fourth decrement in kg of CO2 per kWh of power produced. Also, zero SOx and NOx emissions were observed compared to coal based thermal power plants. It is noted that optimum performance of gasification system at gasifier pressure of 2 bar, air-fuel ratio of 0.1, steam-fuel ratio of 0.25 and flue gas-fuel ratio of 1.00. The proposed cycle presents itself suitable for further research and its application to coal based thermal power plants, providing potential towards supplementary power generation and cleaner exhaust. This research would also significantly contribute to achieve sustainable development goals.
Extractive/Oxidative Desulfurization Optimization of Diesel Feed Stock by Ionic Liquid Utilization/ Thermodynamic Analysis
Authors:   University of Mosul, College of Petroleum and Mining Engineering, Mosul, Iraq, Y. Rahawi Qasim , Berrabia Nadjet ,   University of M’hamed Bougara Boumerdes, Petrochemical Synthesis Laboratory, Boumerdes, Algeria, Hamada Boudjema ,   University of M’hamed Bougara Boumerdes, Petrochemical Synthesis Laboratory, Boumerdes, Algeria, Daabo Ahmed M. ,   University of Mosul, College of Petroleum and Mining Engineering, Mosul, Iraq
Published: November 2021

The current research paper focuses on the physico-chemical optimization’s parameters for the Microwave Assisted Extractive/ Oxidative Desulfurization (MAEOD) of a real Algerian diesel. The oxidative desulfurization was carried out using vanadyl acetyl acetonate as catalyst, hydrogen pyroxide (30%) as oxidant and an acid Bronsted Ionic Liquid (IL) in situ synthesized as extractor. The utilized optimization method is consistent with the full factorial experiment. The engaged parameters are the masse ratio (catalyst/oil), the volume ratio (IL/oil), and the reaction time. Quantification of total sulfur in samples was realized by X-ray fluorescence and a regression model is formed. The most important model parameters’ interaction effects are examined and the ISO-response curves are outlined in order to simulate the optimal conditions. The optimum yield (81.77%) was achieved during a time radiation of 70 s with a catalyst/oil ratio of 0.4% and IL/oil volume ratio of 11%, with correlation 99.21.
Engineering approaches for road construction projects and determination of geotechnical design parameters: Road network improvement of Northern Iraq
Authors:   Department of Environmental Engineering, Faculty of Engineering and Architecture, Sinop University, Sinop, 57000, Turkey., Canoğlu Mustafa Can
Published: November 2021

Transport in Northern Iraq become an important issue in terms of trading due to its geographical position. Road construction between Darbandikhan and Kalar villages in the northern part of Iraq is crucial for the connection of Erbil and Suleymaniye to northeast. The planned road construction requires a detailed environmental and geotechnical study in order to determine geo-engineering parameters of ground conditions. For this purpose this study is carried out to highlight the engineering geological and geotechnical features considering the groundwater conditions of the Darbandikhan - Kalar Road route section. In this context, field and laboratory works were performed along the projected route. Within the scope of field studies, an engineering geology map was generated, a suitable routing was specified and drilling and in-situ testing was completed. Seven boreholes and total 196,5 m geotechnical purposed drilling works performed along the planned route section. The core samples obtained from drilling works are utilized for laboratory testing. As a result of this study information about the bearing capacity, slope stability and basic soil parameters were determined and no problems were encountered.
Removal of heavy metal ions from industrial wastewater using magnetic nanoparticles
Authors:   Department of Chemical Engineering, SRMIST, Kanchipuram Dt., Kattankulathur – 603 203, Tamil Nadu, India, K Anbalagan , M Magesh Kumar ,   Department of Chemical Engineering, SRMIST, Kanchipuram Dt., Kattankulathur – 603 203, Tamil Nadu, India, J. S Sudarsan ,   School of Construction Management (SOCM), NICMAR Pune, Balewadi, Pune 411045, India, S Nithiyanantham ,   Post Graduate and Research Department of Physics, Thiru.Vi.Kalyanasundaram Govt Arts & Science College, Thiruvarur, Tamilnadu 610003, India.
Published: November 2021

In this work Maghemite (γ-Fe2O3) and Magnetite (Fe3O4) nanoparticles were synthesized using Co-precipitation method and characterization was done using X-Ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS) and Fourier Transform Infra-Red Spectroscopy (FTIR). Size of these particles was found to be in the range of 20 to 100 nm and they were used as nano adsorbents for the removal of heavy metal ions like chromium and copper from the artificial wastewater. Adsorption depends with the optimum conditions of parameters such as pH (2.5 and 6.5), contact time (60 and 80) minutes, dosages with at room temperature for chromium and copper were observed with a removal efficiency of 92 %. These particles showed remarkable efficiency in removal of metals. Further, these particles were regenerated for reuse, desorption was done using HCl and NaOH effluent for copper and chromium metals respectively. The removals of pollutant enhanced with magnetic nanoparticles are evident with obtained results. The separation factor (r) lies between 0 and 1 indicating that the favour of Langmuir isotherm for both chromium and copper ions.
Study on Evaluation of the Interconnected Development of the Yangtze River Delta National Innovation Demonstration Zone
Authors: Li Yaping , Diao Li
Published: November 2021

Based on the impression that the integrated regional development of the Yangtze River Delta has been levelled up as China’s national strategy, it is a necessity to realize the high-quality interconnected development of the Yangtze River Delta National Innovation Demonstration Zone. Specifically, it involves the building of evaluation indexes for the interconnected development level of the demonstration zone from such dimensions as industry, economy, policy, space and ecology, determination of weights of various indexes based on the aggregation method for the expert judgment matrix, and design of an evaluation model for the interconnected development level. On this basis, the interconnected development level between different demonstration zones and the contributions of different indexes to the interconnected development level are studied by conducting empirical study on the evaluation of the interconnected development level of demonstration zones.
Analysis on the Risk of Rural Poverty and the Management Path of Preventing Poverty Return – A Case Study of Poor Households Filing and Card in Guangdong Province in 2020
Authors: Peng Xiaojie , Bo Xuelian , Zheng Xingzhong
Published: November 2021

In 2020, China has completed the battle to get rid of poverty with the goal of eliminating absolute poverty. However, many risks of inducing poverty in rural areas still exist. Controlling and responding to the risk of poverty is a key task to prevent the recurrence of poverty after poverty eradication. At present, the total risk of rural families has increased, the level of risk units has diversified, and the traditional risk and non-traditional risk coexist; rural risk not only has the commonness of risk trajectory, but also has the particularity of closer combination with natural factors and more prone to risk accumulation and superposition. Based on this, we should establish the concept of high-quality poverty alleviation, clarify the identification criteria for returning to poverty, establish an early warning mechanism for returning to poverty risk, and pay attention to the follow-up consolidation needs, so as to timely and effectively resolve the returning to poverty risk.
Relationship of some metabolic Hormones with Increased Live Body Weight of Male and Female of Karakul and Awassi Lambs
Authors: Aljubouri Thamer R. S. , Al-Khafaji Firas M. , Al-Shuhaib & Mohammed Baqur S.
Published: November 2021

This study was conducted in the animal field of the Al-Kafeel Company from November 2019 till May 2020 to investigate the possible association between growth hormone (GH) and thyroxine (T4) with the growth traits in Awassi and Karakul sheep. The total number of animals which used in the study was 60 lambs, 28 (13 males and 15 females) from Karakul and 32 (18 males and 14 females) from Awassi. Blood samples were collected at birth, weaning, and six months of age, and both GH and T4 concentrations were measured. Results showed higher values of T4 for Karakul as compared with Awassi at birth and weaning. Karakul breed was also exhibited significantly higher values of GH over Awassi breed only at weaning, while, no significant differences were observed at birth and six months of age. Karakul lambs showed higher weights as compared with Awassi lambs at all studied periods. A highly significant (p < 0.01) positive correlation was observed between T4 concentration and the weight of lambs at most studied periods. Whereas, GH did not exhibit any correlation with growth traits measured in both breeds. The elevated T4 might be one of the reasons for superiority of Karakul over Awassi breed in live body weights. This high correlation between T4 and growth traits could be used in the early selection of lambs to improve the weights of sheep at marketing.
EFEK AFRODISIAKA EKSTRAK KULIT BATANG SANREGO (Lunasia amara Blanco) TERHADAP MENCIT JANTAN (Mus musculus)
Authors: Hasan Hamsidar , Akuba Juliyanty , Wilkinson Beatrice Nathania
Published: November 2021

Sanrego (Lunasia amara Blanco) merupakan salah satu jenis tanaman yang digunakan sebagai afrodisiaka oleh masyarakat Sulawesi Selatan. Penelitian ini bertujuan untuk mengetahui efek afrodisiaka dari ekstrak n-heksan, kloroform, etil asetat dan metanol kulit batang Sanrego (Lunasia amara Blanco) serta mengetahui dosis yang diperlukan untuk memberikan efek afrodisiaka pada mencit jantan. Metode ekstraksi yang digunakan adalah maserasi bertingkat menggunakan pelarut dengan kepolaran meningkat yaitu n-heksan, kloroform, etil asetat dan metanol. Dilakukan pengamatan pada mencit serta menghitung jumlah Introduksi (Pendekatan), Climbing(Penunggangan) dan Coitus(Senggama) selama 5 hari. Data dianalisis menggunakan SPSS One way Anova. Hasil penelitian skrining fitokimia menunjukkan adanya senyawa steroid yang terkandung dalam ekstrak N-Heksan, kloroform, etil asetat dan metanol, terdapat senyawa flavonoid dalam ekstrak kloroform, etil asetat, metanol. Terdapat senyawa tanin dalam ekstrak etil asetat dan metanol dan terdapat senyawa alkaloid dalam ekstrak metanol. Ekstrak yang memberikan efek afrodisiaka yaitu ekstrak metanol dan dosis yang diperlukan untuk memberikan efek afrodisiaka pada mencit yaitu 35mg/kgBB dan 70 mg/kgBB. Hasil analisis data One way Anova (p kurang dari 0,01) dengan tingkat kepercayaan 99%
Contemporary Business Issues II
Authors: Yılmaz Sefer , Özbek Adem , Kul Bekir , Canbaloğlu Bilge , Gürgün Gözde , Yaman Fatih , Yılmaz Hakan , Şimşek Halil , Taş Mehmet Ali , Akcan Serap , Başar Ufuk , Aydoğan Sefer , Kuruşçu Mehmet
Published: November 2021

Based in Ankara in Turkey, the independent academic publisher, Akademisyen Publishing House, has been publishing books for almost 30 years. As the directors of Akademisyen Publishing House, we are proud to publish around 1500 books across disciplines so far, especially in Health Sciences. We also publish books in Social Sciences, Educational Sciences, Physical Sciences, and also books on cultural and artistic topics.Akademisyen Publishing House has recently commenced the process of publishing books in the international arena with the “Scientific Research Book” series in Turkish and English. The publication process of the books, which is expected to take place in March and September every year, will continue with thematic subtitles across disciplines.
Financial Education Phases Affecting Fınancial Literacy
Adem ÖZBEK
Priceless Value Of Turkey: Ethics And Corporate Philanthropy
Bekir KUL
Does Economic Policy Uncertainty Affect the Banking Credit Risk in Emerging and Developing Europe?
Bilge CANBALOĞLU
Gözde GÜRGÜN
Examination Of Succesion Planning According To Strategic Human Resources Perspective, With The Approach Of Human Resources Management In Business Continuity Management
Fatih YAMAN
Management Practices For Business Continuty During The Covid-19
Pandemic Crisis Period
Hakan YILMAZ
Strategic Human Resources Management In Global Aviation Sector From Past To Future
Halil ŞİMŞEK
A Systematic Literature Review Of Green
Supplier Selection Practices
Mehmet Ali TAŞ
Serap AKCAN
Public Health Management Practices In Context Of Contingency Approach
Sefer AYDOĞAN
Mehmet KURUŞCU
Managerial Effectiveness In Multicultural Global Business Environment
Ufuk BAŞAR
INTERNATIONAL COMPETITIVENESS OF THE FURNITURE MANUFACTURING– LESSON FROM THE SELECTED EU COUNTRIES
Authors: GRZEGORZEWSKA EMILIA , SEDLIAČIKOVÁ MARIANA , JELAČIĆ DENIS
Published: November 2021

ThisstudyaimstocompareandevaluatetheinternationalcompetitivenessofthefurnitureindustryintheselectedEuropeanUnion(EU)countriesusingchosenresult-orientedindicators.TheresultsfoundthatcountrieswiththehighestlevelsofinternationalcompetitivenessofthefurnitureindustryincludedPoland,RomaniaandItaly.Incontrast,thecomparativeadvantageofGermany,whichisthelargestfurnitureexporterintheEU,wasnotassignificant.NocomparativeadvantageinthefurnituretradewasobservedinFranceandUnitedKingdom,whichisconfirmedbythenegativevaluesoftheRelativeTradeAdvantage(RTA)indexandbyunfavorablevaluesoftheexportspecializationindex.Theresultspresentedinthearticleexpandtheexistingknowledgeintheareaofassessingtheinternationalcompetitivenessofthelargestfurnitureexporters.
Christian Advocacy Ministry on Pandemics: The Ghanaian Example on HIV/AIDS
Authors: Opuni-Frimpong Kwabena
Published: November 2021

The study is an examination of the various Christian advocacy approaches that the church in Ghana has adopted in its role in the fight against the AIDS pandemic. The study seeks to make the Ghanaian experience available for Christian advocacy ministry for other pandemics. The study as a qualitative one focused on library research. Available primary and secondary materials on the church’s participation in the AIDS pandemic were examined and analyzed. Much attention was paid to reports, addresses, study materials and policy documents on the pandemic by the World Council of Churches, Christian Council of Ghana and the Presbyterian Church of Ghana. The study has observed that provision of leadership, capacity building of church leaders, education and awareness creation, the relevance of the Christian message of hope in a moment of despair and Christian advocacy ministry have made significant contributions to the Christian advocacy on the HIV/AIDS in Ghana. The study further provides insights for studies in church and society and the construction of public theology on pandemics in African Christianity.

Keywords: Advocacy Ministry, Pandemics, Capacity Building, Church Leadership
SiO Outflows as Tracers of Massive Star Formation in Infrared Dark Clouds
Authors: Liu Mengyao , Tan Jonathan C. , Marvil Joshua , Kong Shuo , Rosero Viviana , Caselli Paola , Cosentino Giuliana
Published: November 2021

To study the early phases of massive star formation, we present ALMA observations of SiO(5−4) emission and VLA observations of 6 cm continuum emission toward 32 Infrared Dark Cloud clumps, spatially resolved down to ≲0.05 pc. Out of the 32 clumps, we detect SiO emission in 20 clumps, and in 11 of them the SiO emission is relatively strong and likely tracing protostellar outflows. Some SiO outflows are collimated, while others are less ordered. For the six strongest SiO outflows, we estimate basic outflow properties. In our entire sample, where there is SiO emission, we find 1.3 mm continuum and infrared emission nearby, but not vice versa. We build the spectral energy distributions (SEDs) of cores with 1.3 mm continuum emission and fit them with radiative transfer models. The low luminosities and stellar masses returned by SED fitting suggest these are early-stage protostars. We see a slight trend of increasing SiO line luminosity with bolometric luminosity, which suggests more powerful shocks in the vicinity of more massive YSOs. We do not see a clear relation between the SiO luminosity and the evolutionary stage indicated by L/M. We conclude that, as a protostar approaches a bolometric luminosity of ∼102
L
⊙, the shocks in the outflow are generally strong enough to form SiO emission. The VLA 6 cm observations toward the 15 clumps with the strongest SiO emission detect emission in four clumps, which is likely from shock-ionized jets associated with the more massive ones of these protostellar cores.
Modeling the Galactic Neutron Star Population for Use in Continuous Gravitational-wave Searches
Authors: Reed Brendan T. , Deibel Alex , Horowitz C. J.
Published: November 2021

Searches for continuous gravitational waves (GW) from unknown Galactic neutron stars provide limits on the shapes of neutron stars. A rotating neutron star will produce GW if asymmetric deformations exist in its structure that are characterized by the star’s ellipticity. In this study, we use a simple model of the spatial and spin distribution of Galactic neutron stars to estimate the total number of neutron stars probed, using GW, to a given upper limit on the ellipticity. This may help optimize future searches with improved sensitivity. The improved sensitivity of third-generation GW detectors may increase the number of neutron stars probed, to a given ellipticity, by factors of 100 to 1000.
Radiative Turbulent Flares in Magnetically Dominated Plasmas
Authors: Nättilä Joonas , Beloborodov Andrei M.
Published: November 2021

We perform 2D and 3D kinetic simulations of reconnection-mediated turbulent flares in a magnetized electron-positron plasma, with weak and strong radiative cooling. Such flares can be generated around neutron stars and accreting black holes. We focus on the magnetically dominated regime where tension of the background magnetic field lines exceeds the plasma rest-mass density by a factor σ
0 > 1. In the simulations, turbulence is excited on a macroscopic scale l
0, and we observe that it develops by forming thin, dynamic current sheets on various scales. The deposited macroscopic energy dissipates by energizing thermal and nonthermal particles. The particle energy distribution is shaped by impulsive acceleration in reconnecting current sheets, gradual stochastic acceleration, and radiative losses. We parameterize radiative cooling by the ratio



of light-crossing time l
0/c to a cooling timescale, and study the effect of increasing



on the flare. When radiative losses are sufficiently weak,


<

σ

0

−
1

, the produced emission is dominated by stochastically accelerated particles, and the radiative power depends logarithmically on



. The resulting radiation spectrum of the flare is broad and anisotropic. In the strong-cooling regime,


>

σ

0

−
1

, stochastic acceleration is suppressed, while impulsive acceleration in the current sheets continues to operate. As



increases further, the emission becomes dominated by thermal particles. Our simulations offer a new tool to study particle acceleration by turbulence, especially at high energies, where cooling competes with acceleration. We find that the particle distribution is influenced by strong intermittency of dissipation, and stochastic acceleration cannot be described by a universal diffusion coefficient.
Espresso and Stochastic Acceleration of Ultra-high-energy Cosmic Rays in Relativistic Jets
Authors: Mbarek Rostom , Caprioli Damiano
Published: November 2021

In the espresso scenario, ultra-high-energy (UHE) cosmic rays (CRs) are produced via a one-shot reacceleration of galactic-like CRs in the relativistic jets of active galactic nuclei, independently of the scattering rate dictated by magnetic fluctuations. In Mbarek & Caprioli (2019) we traced test-particle CRs in high-resolution magnetohyrodynamic (MHD) jet simulations and found that the associated spectral slope, chemical composition, and anisotropy are consistent with UHECR phenomenology. In this work, we extend such an analysis by including subgrid pitch-angle scattering to model small-scale magnetic turbulence that cannot be resolved by MHD simulations. We find that a large scattering rate unlocks stochastic acceleration and fosters the energization of lower-energy CRs, which eventually leads to harder UHECR spectra. Yet, the particles that achieve the highest energies (up to the Hillas limit) are invariably produced by espresso acceleration and their spectrum is independent of the assumed subgrid scattering rate.
Linking Outer Disk Pebble Dynamics and Gaps to Inner Disk Water Enrichment
Authors: Kalyaan Anusha , Pinilla Paola , Krijt Sebastiaan , Mulders Gijs D. , Banzatti Andrea
Published: November 2021

Millimeter continuum imaging of protoplanetary disks reveals the distribution of solid particles and the presence of substructures (gaps and rings) beyond 5–10 au, while infrared (IR) spectra provide access to abundances of gaseous species at smaller disk radii. Building on recent observational findings of an anti-correlation between the inner disk water luminosity and outer dust disk radius, we aim here at investigating the dynamics of icy solids that drift from the outer disk and sublimate their ice inside the snow line, enriching the water vapor that is observed in the IR. We use a volatile-inclusive disk evolution model to explore a range of conditions (gap location, particle size, disk mass, and α viscosity) under which gaps in the outer disk efficiently block the inward drift of icy solids. We find that inner disk vapor enrichment is highly sensitive to the location of a disk gap, yielding for each particle size a radial “sweet spot” that reduces the inner disk vapor enrichment to a minimum. For pebbles of 1–10 mm in size, which carry the most mass, this sweet spot is at 7–15 au, suggesting that inner gaps may have a key role in reducing ice delivery to the inner disk and may not allow the formation of Earths and super-Earths. This highlights the importance of observationally determining the presence and properties of inner gaps in disks. Finally, we argue that the inner water vapor abundance can be used as a proxy for estimating the pebble drift efficiency and mass flux entering the inner disk.
Ambipolar Electric Field and Potential in the Solar Wind Estimated from Electron Velocity Distribution Functions
Authors: Berčič Laura , Maksimović Milan , Halekas Jasper S. , Landi Simone , Owen Christopher J. , Verscharen Daniel , Larson Davin , Whittlesey Phyllis , Badman Samuel T. , Bale Stuart. D. , Case Anthony W. , Goetz Keith , Harvey Peter R. , Kasper Justin C. , Korreck Kelly E. , Livi Roberto , MacDowall Robert J. , Malaspina David M. , Pulupa Marc , Stevens Michael L.
Published: November 2021

The solar wind escapes from the solar corona and is accelerated, over a short distance, to its terminal velocity. The energy balance associated with this acceleration remains poorly understood. To quantify the global electrostatic contribution to the solar wind dynamics, we empirically estimate the ambipolar electric field (E
∥) and potential (Φr,∞). We analyze electron velocity distribution functions (VDFs) measured in the near-Sun solar wind between 20.3 R

S
and 85.3 R

S
by the Parker Solar Probe. We test the predictions of two different solar wind models. Close to the Sun, the VDFs exhibit a suprathermal electron deficit in the sunward, magnetic-field-aligned part of phase space. We argue that the sunward deficit is a remnant of the electron cutoff predicted by collisionless exospheric models. This cutoff energy is directly linked to Φr,∞. Competing effects of E
∥ and Coulomb collisions in the solar wind are addressed by the Steady Electron Runaway Model (SERM). In this model, electron phase space is separated into collisionally overdamped and underdamped regions. We assume that this boundary velocity at small pitch angles coincides with the strahl break-point energy, which allows us to calculate E
∥. The obtained Φr,∞ and E
∥ agree well with theoretical expectations. They decrease with radial distance as power-law functions with indices α
Φ = −0.66 and α
E = −1.69. We finally estimate the velocity gained by protons from electrostatic acceleration, which equals 77% calculated from the exospheric models, and 44% from the SERM model.
Molecules with ALMA at Planet-forming Scales (MAPS). I. Program Overview and Highlights
Authors: Öberg Karin I. , Guzmán Viviana V. , Walsh Catherine , Aikawa Yuri , Bergin Edwin A. , Law Charles J. , Loomis Ryan A. , Alarcón Felipe , Andrews Sean M. , Bae Jaehan , Bergner Jennifer B. , Boehler Yann , Booth Alice S. , Bosman Arthur D. , Calahan Jenny K. , Cataldi Gianni , Cleeves L. Ilsedore , Czekala Ian , Furuya Kenji , Huang Jane , Ilee John D. , Kurtovic Nicolas T. , Le Gal Romane , Liu Yao , Long Feng , Ménard François , Nomura Hideko , Pérez Laura M. , Qi Chunhua , Schwarz Kamber R. , Sierra Anibal , Teague Richard , Tsukagoshi Takashi , Yamato Yoshihide , van ’t Hoff Merel L. R. , Waggoner Abygail R. , Wilner David J. , Zhang Ke
Published: November 2021

Planets form and obtain their compositions in dust- and gas-rich disks around young stars, and the outcome of this process is intimately linked to the disk chemical properties. The distributions of molecules across disks regulate the elemental compositions of planets, including C/N/O/S ratios and metallicity (O/H and C/H), as well as access to water and prebiotically relevant organics. Emission from molecules also encodes information on disk ionization levels, temperature structures, kinematics, and gas surface densities, which are all key ingredients of disk evolution and planet formation models. The Molecules with ALMA at Planet-forming Scales (MAPS) ALMA Large Program was designed to expand our understanding of the chemistry of planet formation by exploring disk chemical structures down to 10 au scales. The MAPS program focuses on five disks—around IM Lup, GM Aur, AS 209, HD 163296, and MWC 480—in which dust substructures are detected and planet formation appears to be ongoing. We observed these disks in four spectral setups, which together cover ∼50 lines from over 20 different species. This paper introduces the Astrophysical Journal Supplement’s MAPS Special Issue by presenting an overview of the program motivation, disk sample, observational details, and calibration strategy. We also highlight key results, including discoveries of links between dust, gas, and chemical substructures, large reservoirs of nitriles and other organics in the inner disk regions, and elevated C/O ratios across most disks. We discuss how this collection of results is reshaping our view of the chemistry of planet formation.
Molecules with ALMA at Planet-forming Scales (MAPS). XVII. Determining the 2D Thermal Structure of the HD 163296 Disk
Authors: Calahan Jenny K. , Bergin Edwin A. , Zhang Ke , Schwarz Kamber R. , Öberg Karin I. , Guzmán Viviana V. , Walsh Catherine , Aikawa Yuri , Alarcón Felipe , Andrews Sean M. , Bae Jaehan , Bergner Jennifer B. , Booth Alice S. , Bosman Arthur D. , Cataldi Gianni , Czekala Ian , Huang Jane , Ilee John D. , Law Charles J. , Le Gal Romane , Long Feng , Loomis Ryan A. , Ménard François , Nomura Hideko , Qi Chunhua , Teague Richard , van’t Hoff Merel L. R. , Wilner David J. , Yamato Yoshihide
Published: November 2021

Understanding the temperature structure of protoplanetary disks is key to interpreting observations, predicting the physical and chemical evolution of the disk, and modeling planet formation processes. In this study, we constrain the two-dimensional thermal structure of the disk around the Herbig Ae star HD 163296. Using the thermochemical code RAC2D, we derive a thermal structure that reproduces spatially resolved Atacama Large Millimeter/submillimeter Array observations (∼0.″12 (13 au)–0.″25 (26 au)) of 12CO J = 2 − 1, 13CO J = 1 − 0, 2 − 1, C18O J = 1 − 0, 2 − 1, and C17O J = 1 − 0, the HD J = 1 − 0 flux upper limit, the spectral energy distribution (SED), and continuum morphology. The final model incorporates both a radial depletion of CO motivated by a timescale shorter than typical CO gas-phase chemistry (0.01 Myr) and an enhanced temperature near the surface layer of the the inner disk (z/r ≥ 0.21). This model agrees with the majority of the empirically derived temperatures and observed emitting surfaces derived from the J = 2 − 1 CO observations. We find an upper limit for the disk mass of 0.35 M
⊙, using the upper limit of the HD J = 1 − 0 and J = 2 − 1 flux. With our final thermal structure, we explore the impact that gaps have on the temperature structure constrained by observations of the resolved gaps. Adding a large gap in the gas and small dust additionally increases gas temperature in the gap by only 5%–10%. This paper is part of the MAPS special issue of the Astrophysical Journal Supplement.
Molecules with ALMA at Planet-forming Scales (MAPS). VI. Distribution of the Small Organics HCN, C2H, and H2CO
Authors: Guzmán Viviana V. , Bergner Jennifer B. , Law Charles J. , Öberg Karin I. , Walsh Catherine , Cataldi Gianni , Aikawa Yuri , Bergin Edwin A. , Czekala Ian , Huang Jane , Andrews Sean M. , Loomis Ryan A. , Zhang Ke , Le Gal Romane , Alarcón Felipe , Ilee John D. , Teague Richard , Cleeves L. Ilsedore , Wilner David J. , Long Feng , Schwarz Kamber R. , Bosman Arthur D. , Pérez Laura M. , Ménard François , Liu Yao
Published: November 2021

Small organic molecules, such as C2H, HCN, and H2CO, are tracers of the C, N, and O budget in protoplanetary disks. We present high-angular-resolution (10–50 au) observations of C2H, HCN, and H2CO lines in five protoplanetary disks from the Molecules with ALMA at Planet-forming Scales (MAPS) ALMA Large Program. We derive column density and excitation temperature profiles for HCN and C2H, and find that the HCN emission arises in a temperate (20–30 K) layer in the disk, while C2H is present in relatively warmer (20–60 K) layers. In the case of HD 163296, we find a decrease in column density for HCN and C2H inside one of the dust gaps near ∼83 au, where a planet has been proposed to be located. We derive H2CO column density profiles assuming temperatures between 20 and 50 K, and find slightly higher column densities in the colder disks around T Tauri stars than around Herbig Ae stars. The H2CO column densities rise near the location of the CO snowline and/or millimeter dust edge, suggesting an efficient release of H2CO ices in the outer disk. Finally, we find that the inner 50 au of these disks are rich in organic species, with abundances relative to water that are similar to cometary values. Comets could therefore deliver water and key organics to future planets in these disks, similar to what might have happened here on Earth. This paper is part of the MAPS special issue of the Astrophysical Journal Supplement.
Molecules with ALMA at Planet-forming Scales (MAPS). V. CO Gas Distributions
Authors: Zhang Ke , Booth Alice S. , Law Charles J. , Bosman Arthur D. , Schwarz Kamber R. , Bergin Edwin A. , Öberg Karin I. , Andrews Sean M. , Guzmán Viviana V. , Walsh Catherine , Qi Chunhua , van ’t Hoff Merel L. R. , Long Feng , Wilner David J. , Huang Jane , Czekala Ian , Ilee John D. , Cataldi Gianni , Bergner Jennifer B. , Aikawa Yuri , Teague Richard , Bae Jaehan , Loomis Ryan A. , Calahan Jenny K. , Alarcón Felipe , Ménard François , Le Gal Romane , Sierra Anibal , Yamato Yoshihide , Nomura Hideko , Tsukagoshi Takashi , Pérez Laura M. , Trapman Leon , Liu Yao , Furuya Kenji
Published: November 2021

Here we present high-resolution (15–24 au) observations of CO isotopologue lines from the Molecules with ALMA on Planet-forming Scales (MAPS) ALMA Large Program. Our analysis employs observations of the (J = 2–1) and (1–0) lines of 13CO and C18O and the (J = 1–0) line of C17O for five protoplanetary disks. We retrieve CO gas density distributions, using three independent methods: (1) a thermochemical modeling framework based on the CO data, the broadband spectral energy distribution, and the millimeter continuum emission; (2) an empirical temperature distribution based on optically thick CO lines; and (3) a direct fit to the C17O hyperfine lines. Results from these methods generally show excellent agreement. The CO gas column density profiles of the five disks show significant variations in the absolute value and the radial shape. Assuming a gas-to-dust mass ratio of 100, all five disks have a global CO-to-H2 abundance 10–100 times lower than the interstellar medium ratio. The CO gas distributions between 150 and 400 au match well with models of viscous disks, supporting the long-standing theory. CO gas gaps appear to be correlated with continuum gap locations, but some deep continuum gaps do not have corresponding CO gaps. The relative depths of CO and dust gaps are generally consistent with predictions of planet–disk interactions, but some CO gaps are 5–10 times shallower than predictions based on dust gaps. This paper is part of the MAPS special issue of the Astrophysical Journal Supplement.