Main Channel Research Articles

Digitized Printed Strategic Intervention Material in Science in District I of Antipolo City: Basis for Enhancement Model

Digitization, technology, and scientific education are strong educational reform drivers. Modern educational institutions use computers and the Internet for all their activities. It’s everywhere now. Thus, digitally printed science intervention material is crucial in schools and society. Today, digitalized printed materials are the main teaching and learning channel. The Philippine Department of Education (DepEd) uses extracurricular activities to help students who struggle in science, technology, and other subjects. Educators, administrators, and curriculum planners use digitally enhanced printed materials and multimedia instructions to develop every aspect of teaching and learning. This study assessed the validity and acceptability of the Digitized Printed Strategic Intervention Material (DPSIM) in teaching Science as expected against evaluation. The respondents of the study were one (1) Technology Expert, five (5) Science Administrators, and one hundred (100) Science teachers who were described in terms of position, educational attainment, training attended in ICT, teaching experiences, and the ability to handle ICT. The validity is assessed in terms of content, manner of presentation, language and style, and evaluative tools. Acceptability is assessed in terms of clarity, usefulness, suitability, adequacy, and timeliness. Various resources such as books, published studies on the net, and other materials were gathered in the construction of the research questionnaire. Descriptive Statistics such as Mean and Frequency, T-test, and ANOVA were utilized to test the statistical significance of the variables presented. Results revealed that there is no significant difference in the assessment of the two groups (expected and evaluated responses) of respondents on the validity of the Digitized Printed Strategic Intervention Material (DPSIM), but there is a significant difference in the assessment of respondents in terms of acceptability of DPSIM. When respondents were grouped according to their profile in terms of position, educational attainment, training attended in Information Communication Technology (ICT), teaching experience, and the ability to handle ICT in Teaching, it was identified that differences in the responses for validity were brought about by the respondent’s difference in ICT training attended and their ability to handle ICT in teaching. The validity of DPSIM is perceived to be a high extent, with Application, Method of Presentation, Language and Style, and Evaluative Tools as the criteria that need further improvement. For the acceptability of DPSIM, there is a significant difference in the responses when grouped according to profile. However, it is worth noting that overall, no criteria were perceived to be needing improvement. Acceptability has also been categorized to a very high extent. It concluded that the Digitized Printed Strategic Intervention Material (DPSIM) is an effective tool in teaching Science. The study included that school administrators should evaluate the DPSIM whether its contents conform to the curriculum standards. Teachers should first examine the DPSIM use to determine the contents that align with the objective of the lesson. Parents should support children with technology materials that supplement the lesson; pupils can explore the DPSIM, which promotes independent learning; and future researchers can conduct similar studies that assess developed DPSIM if the same education will be conducted in the future. Keyword: Digitized Printed Strategic Intervention Material (DPSIM)

Wafer-scale silicon microfabrication technology toward realization of low-cost sub-THz waveguide devices

This paper presents a wafer-scale silicon microfabrication technology for the sub-terahertz (sub-THz) waveguide device mass production. Based on the effective scheme, a WR-5 (140–220 GHz) straight rectangular waveguide and a WR-2.8 (260–400 GHz) rectangular waveguide bandpass filter are implemented as demonstrated examples. The silicon deep reactive ion etching (DRIE) process is employed to etch through the total thickness of the silicon wafer and form the main waveguide channels. Then, a low-temperature thermal compression process is used to bond the trough-etched wafer with the top and bottom metallised silicon wafers to form the closed waveguide structures without any precise alignment process. The fabricated waveguide has the benefit of low transmission loss (0.03–0.05 dB mm−1) at the whole G band. Besides, to measure the fabricated WR-2.8 waveguide filter and solve the measuring equipment standard waveguide difference, silicon micromachined waveguide transitions are explored and fabricated to match two different frequency-band modules for measuring the waveguide filters in the desired full frequency band, which also has a potential application for the different size waveguide conversion. The measured results agree well with the simulated ones. The measured 3 dB bandwidth is 9.3%, with a central frequency of 343 GHz; the average insertion loss (IL) is about 1.6 dB in the pass band, including two extra straight waveguides of 8 mm length on input/output ends and two external waveguide-to-waveguide transitions. The proposed method provides a feasible and cost-effective solution for the mass production of high-performance waveguide devices and integrated systems in sub-THz frequency bands and beyond.

Hydrological Changes and Sediment Dynamics in the Inner Mongolia Section of the Yellow River: Implications for Reservoir Management

The Inner Mongolia section of the Yellow River is a primary alluvial segment of the main channel. The variations in water and sediment not only alter the cross-sectional morphology and flow capacity of the river but also impact the scheduling of upstream cascade reservoirs. Based on runoff and sediment load data and topographic information from typical hydrological stations, the characteristics of runoff and sediment load variations and the evolutionary pattern of siltation in the Inner Mongolia River section were analyzed via trend analysis methods, Mann–Kendall test methods, the sediment load transport rate method, and the water level–flow relationship. The results showed that the water and sediment loads at the hydrological stations in the Inner Mongolia River section significantly changed from the 1960s to after 2000, with runoff decreasing by approximately 22% to 32% and the sediment load decreasing by approximately 65% to 73%. Sedimentation in the river section generally increased, and the average annual siltation amount reached 0.144 billion t. The joint utilization of the Longyangxia and Liujiaxia reservoirs in 1987 was the main reason for the rapid increase in siltation, and siltation in the Inner Mongolia River section was slightly reduced after 2005. In addition, the critical sediment load coefficients of the Bayangaole–Sanhuhekou and Sanhuhekou–Toudaoguai River sections were 0.0073 and 0.0051 kg·s/m6, respectively, from 1952 to 1968, and 0.0053 and 0.0037 kg·s/m6, respectively, from 1969 to 2020. This study could provide technical support for river flood control and reservoir water sediment regulation in Inner Mongolia.

Uncovering the endogenous features of potassium salts' global transfer: A complex network perspective.

Potassium is a decisive strategic resource to ensure food safety production and supply, which many nations define as a critical metal. Due to the unbalanced distribution of resources and production capacity and the separation of the primary potassium-consuming and supplying countries, international trade is the main supply channel for potassium-consuming countries to acquire enough resources. Understanding the characteristics of potassium trade networks and the evolution of trade patterns is essential for supply security. To explore this issue, this paper employs the complex network theory to quantitatively analyze the evolution characteristics of the global potassium trade network (PTN) from 2000 to 2021. The results show (1) Overall, the potassium trade shows a trend of gradual prosperity, efficiency, and concentration; (2) During the two decades, the main exporting countries of potassium remained stable, while imports changed significantly; (3) The evolution of the potassium trade community has characterized the fragmentation-regionalization-high concentration over time; (4) The trade flow of PTN is unbalanced, and few countries show outstanding capabilities but a single function. These findings would help trade policymakers manage the supply of strategic raw materials more effectively.

Effects of Ramp-Induced Incident Shock Impingement Under Various Slope Angle Configurations in a Strut-Based/Cavity-Assisted Supersonic Combustor

ABSTRACT The present study conducts a numerical investigation into the effects of ramp-induced shock impingement with different opening angles on the global flow-field and combustion behaviors within a strut-based/cavity-assisted scramjet combustor. To reproduce the intricate physical phenomena and all inflow properties of the primary channel, two-dimensional Reynolds-averaged Navier–Stokes (RANS) equations integrated with the shear stress transport (SST) k − ω turbulence model is implemented. The current approach considers several slope angle configurations of the ramp since they generate various shock systems that differ in magnitudes and coherent structures, substantially affecting the combustion efficiencies and chemical species distributions. Results reveal that an optimal shock angle of the ramp in correspondence with the current operating conditions can be achieved at 20°, which increases the combustion efficiency by 11% at the end of the cavity trailing edge without provoking excessive loss of total mass-flux-weighted pressure recovery. However, further expanding the slope angle above the optimum will trigger the flow blockage mechanism which enlarges the recirculation region on both sides of the ramp, simultaneously initiate their local thickening processes and create shock train areas owing to intensive interactions with the turbulent boundary layers. These phenomena are known for decreasing the total pressure ratio, adversely affecting all performance metrics of interest and destabilizing the main channel flow path.

Coping with job loss: evidence from military base closures

AbstractWe examine how workers adjust in response to an unexpected job loss. Using the closure of military bases in Sweden, we find that displaced workers experience permanent income losses and immediately adjust along two main channels: regional and sector mobility. Displaced military workers are more likely to move to another municipality, start commuting, and change sectors. We also find that workers with mobility restrictions are less likely to change regions and they exhibit lower earnings in the longer run, a result that might help to explain some of the permanent income losses found in the literature.

The Role of E-Government in the Promotion of Municipal Service Delivery in South Africa

The advent of the fourth industrial revolution necessitates that government institutions move away from the traditional paper-based system to an electronic system. Many countries in Africa, including South Africa, have adopted the e-government system as one of the main delivery channels for municipal services and information to society (Mafunisa Consulting, 2021). However, despite the government's ability to establish a new public service model where all government agencies provide their constituents with modern, streamlined, and seamless services (Norris and Moon, 2005). Municipalities in South Africa are regarded as entities that provide direct services to the citizens, however are not financially self-sufficient and often lack the necessary infrastructure such as ICT infrastructure to carry out their duties to deliver e-services to the society at large (Development Bank of South Africa, 2023). Many people in rural areas are affected by the lack of ICT infrastructures and basic digital literacy to enable the participation and accessibility of digital services. Therefore, for the society to participate in e-government, it should be proficient with ICT skills, assisted by the availability of ICT infrastructure within their area. As a result, these people are left out of the participation of e-government services due to the complexities associated with the lack of ICT infrastructure. Because the ICT infrastructure is the backbone and a critical component for implementing the e-government system to ensure digital public administration. Therefore, the study examines the role of e-government in the promotion of municipal service delivery within the South African public sector environment. The main objective of the study is to establish the best electronic government mechanisms that will help the South African government in delivering sustainable services. The study adopted a qualitative research methodology with specific reference to a conceptual approach based extensively on secondary data.

Segmented growth of reactivated major bounding faults and their control on basin structures: Insights from the Nanpu Sag, Bohai Bay Basin, eastern China

AbstractA thorough insight into the initiation, segmentation, propagation and interaction of multitrend basin‐bounding faults is crucial to restoring the growth history of the faults and clarifying the fault growth pattern and its influence on the structures developed along the margin due to the growth of the basin‐bounding faults, but systematic studies on the individual influence of the evolution of each fault segment on the present structure are lacking. Based on 3D seismic data, the timing and growth of multitrend basin‐bounding faults were analysed using T‐z plots and throw backstripping, allowing us to determine the individual effects that each fault segment evolution exerteds on the present‐day configuration of the northern margin of the Nanpu Sag. The basin‐bounding fault is composed of the Xinanzhuang and Baigezhuang faults, and the Xinanzhuang fault comprises three linked segments with varying orientations (i.e., NE–SW, E–W, and NNE–SSW). In comparison, the Baigezhuang fault comprises only two linked NW–SE‐oriented fault segments. The evolution process can be divided into three stages. (1) During the early synrift I stage, namely, the isolated fault stage, five isolated multitrend basin‐bounding segments were active. (2) During the late synrift I stage, namely, the hard‐linkage stage, the five segments propagated laterally and linked with each other, behaving as a single fault. Meanwhile, the NE‐trending No. 5 Fault bifurcated upward from the basin‐bounding fault to accommodate local stress, and the NW‐trending Gaobei Fault deviated from the basin‐bounding fault controlled by local stresses induced by differential activities of the multitrend fault segments under the same far‐field stress. (3) During the synrift II to postrift linkage development stage, the extension orientation changed from NW–SE‐ to N–S, and additional displacement accumulated along the basin‐bounding fault without further lateral propagation. Newly formed E–W‐trending faults developed orthogonal to the extension orientation and linked with preexisting NE‐ or NW‐trending faults, forming a complex fault zone. In addition, influenced by the geometry of the basin‐bounding fault, the Laoyemiao Anticline formed by gravitational collapse under the dual action of a rollover anticline and transverse anticline. Furthermore, the evolution of the basin‐bounding faults played an important role in controlling the source‐to‐sink system, and the transition zone was the main provenance channel formed by the segmented growth of the faults. This study provides new insight into multitrend large fault evolution, and their impact on basin development provides a comprehensive explanation of the later structures developed in polyphase rifts.

Digital Channels of Employer Brand Formation

Relevance. In modern conditions of high competition in the labor market, new forms of work are becoming particularly relevant, in particular, the creation of an HR brand as a tool for maintaining the company's image and attracting employees. The development of digital technologies has allowed companies to use new channels of employer brand formation – digital. However, despite the existing need, the features of their use have not been fully studied. Social networks and career sites as the main platforms for the formation of an employer's brand are rapidly developing and transforming, which requires their comprehensive research. The purpose is to identify the features of the use of career sites and social networks as the main digital channels for the formation of an employer's brand. Objectives: to reveal the essence and identify the main elements of the employer's brand; to conduct a comparative study of the use of career sites and social networks of four Russian companies: Dodo Pizza, Gulfstream, Chulakov.ru, Exness. Methodology. The methodological basis of the study was the work of G. Martin, S. Hat Trick, T. Ambler, S. Burrow. As a technical tool for the study of social networks, the system of multifactorial analysis of social media "Cribrum" was used, the method of content analysis was used in the study of career websites of companies. Results. As a result of the study, the authors identified the main components of the HR brand broadcast by digital channels focused on basic and additional values. The analysis of digital channels by selected elements revealed the specifics of their use in the formation of the employer's brand. Career sites to a greater extent broadcast additional values of the company, forming a holistic positive image for the general public, without highlighting the target categories of recruiting. Social networks mainly demonstrate the basic values of the company, their content is more specific, focused on certain categories of recruiting. Conclusion. Creating a successful employer brand requires a competent combination of the digital channels considered, taking into account their specifics and the category of recruiting, which will allow HR branding to become a long-term HR strategy for attracting and retaining target groups of employees.

Digital elevation model cell size effect on erosion‐deposition simulation using the unit stream power erosion and deposition model in the dry‐hot valley region of Southwest China

AbstractGully erosion is the main source of sediment in watersheds, and the assessment of soil erosion and deposition in gully systems is very important for land utilization and watershed management. Soil erosion and sediment transport are multiscale, and the digital elevation model (DEM) is one of the most important means to study the scale effect of soil erosion and deposition. To clarify the effect of DEM cell size on soil erosion and deposition in gullies, a series of DEMs with cell sizes of 0.5, 0.7, 1, 1.5, 2, 2.5, 3, 4 and 5 m were generated based on detailed field measurements in dry‐hot valley region. Meanwhile, the unit stream power erosion and deposition (USPED) model was chosen to simulate soil erosion and deposition in this study. The results showed that cell size can greatly influence the average slope and aspect of the DEMs, while the accuracy and average elevation of the DEMs were only affected intensively when the cell size exceeds 3 m. As for the spatial distribution pattern of soil erosion and deposition, the increase of the DEM cell size could cause a concentration of soil erosion and deposition in main channels while weakening the occurrence on hillslopes, and the spatial proximity of soil erosion and deposition would not change with the DEM cell size. The highly positive correlation in simulation results for soil erosion and deposition was primarily observed in DEM cell sizes range of 0.5 to 2 m and from 3 to 5 m. Meanwhile, a slight increase in DEM cell size would significantly affect the simulated results of soil erosion and deposition based on the USPED model when DEM cell size ranged from 0.5 to 0.7 m, whereas the change in DEM cell size would not affect the simulation results when DEM cell size was greater than 0.7 m.

Does large-scale research infrastructure affect regional knowledge innovation, and how? A case study of the National Supercomputing Center in China

Large-scale research infrastructures (LSRIs) are widely acknowledged as a crucial instrument for venturing into the uncharted territories of science and technology, as well as contributing to the well-being of society. However, only a limited number of literature have scrutinized the impact of LSRIs, founded upon a causal inference framework. Moreover, the function of LSRIs in the advancement of innovation at the regional level remains inadequately identified. Drawing on the resource-based view, this study develops a conceptual framework that links the scientific effect of LSRIs to innovation resources in order to assess their impact on knowledge innovation (KI). Taking China’s National Supercomputing Center (NSC) as a case, three major mechanism hypotheses are proposed for the impact of NSC on KI, including basic effect, network effect, and technology effect. Using panel data from 283 cities in China from 2000 to 2020, we employ a spatial difference-in-differences estimation model to examine the impact of NSC on KI. The research finds that: (1) The construction of NSC stimulates KI in local and surrounding areas. (2) The main mechanisms by which NSC promotes KI include the increase in fiscal investment and talents in science, the improvement of digital infrastructure, as well as the enhancement of urban network centrality and innovation efficiency. (3) Geographical proximity, cooperation proximity, and digitization proximity constitute the main channels of policy spillover. (4) NSC has not shown significant promotion of regional innovation convergence, and its radiation influence needs further improvement. (5) The knowledge innovation effects of NSCs manifest heterogeneity based on the distinct knowledge orientation and innovation environment, with this impact being notably pronounced in application innovation-oriented cities such as Shenzhen. The results of this study reveal the positive yet limited impact of NSC on KI and provide a reference for other economies in the areas of LSRIs, digital infrastructure, and the formulation of place-based innovation policy.

Effects of carboxylated styrene‐butadiene latex nanoparticles on channeling leakage and pore structure of oil well cement

AbstractThe exploitation efficiency of oil and gas resources depends on the cementing quality. In cementing engineering, interlayer migration occurs in the underground gas layer with cement hole as the main channel, which seriously threatens the sealing integrity of cement casing and leads to the failure of cementing operation. To improve the gas migration control ability of oil well cement (OWC), two carboxylated styrene‐butadiene latex nanomaterials styrene butadiene latex containing itaconic acid and sodium p‐styrene sulfonate (SBSI) and styrene‐butadiene latex containing methacrylic acid and sodium p‐styrene sulfonate (SBSM) were synthesized. The effects of SBSI and SBSM with different carboxyl structures on the gas migration control ability and pore structure of cement were investigated. The results show that the latex is densely packed on the cement matrix through the dissociation and adsorption behavior of carboxyl groups, and the smaller particle size and lower adsorption are more conducive to the formation of the film. The introduction of latex effectively shortened the transition time of cement gel state and significantly reduced the permeability of interlayer material migration. Compared with OWC, the transition time of cement containing SBSI and SBSM latex (SBSI/OWC and SBSM/OWC) decreased from 28 to 18 and 17 min, respectively, and the filter loss decreased from 60 to 40 and 36 mL, respectively. The isolation effect of the latex film on the interlayer gas and the provision of mechanical support have greatly improved the gas migration control ability of the cement and ensured the cementing quality. In addition, the refinement of cement pore structure caused by latex brings better rheological and mechanical properties to cement. This study clarified the change of latex in the gel transition stage of OWC from liquid to solid and revealed the mechanism of latex on the internal structure change of cement. It broadens the application range of latex nanomaterials in the field of OWC and provides a new possibility for the use of OWC in high temperature and high salt environment.

Discharge Formula and Hydraulics of Rectangular Side Weirs in the Small Channel and Field Inlet

In this study, experimental investigations were conducted on rectangular side weirs with different widths and heights. Corresponding simulations were also performed to analyze hydraulic characteristics including the water surface profile, flow velocity, and pressure. The relationship between the discharge coefficient and the Froude number, as well as the ratios of the side weir height and width to upstream water depth, was determined. A discharge formula was derived based on a dimensional analysis. The results demonstrated good agreement between simulated and experimental data, indicating the reliability of numerical simulations using FLOW-3D software (version 11.1). Notably, significant fluctuations in water surface profiles near the side weir were observed compared to those along the center line or away from the side weir in the main channel, suggesting that the entrance effect of the side weir did not propagate towards the center line of the main channel. The proposed discharge formula exhibited relative errors within 10%, thereby satisfying the flow measurement requirements for small channels and field inlets.

The Impact of Fake News on Social Media Users During the COVID-19 Pandemic, Health, Political and Religious Conflicts: A Deep Look

In this new era of inter-connectedness, the COVID-19 outbreak has been characterized by a rapid surge of misinformation — or “fake news” — about the disease on social media, exacerbating its negative psychological impacts and hindering public health efforts. By providing easy access to and sharing of information in real time, social media is considered the main channel for the distribution of fake news. In this viewpoint, we try to find the main impacts of fake news related to COVID-19 on social media users and propose strategies for limiting its spread. In this regard, we set out four key objectives: studying and evaluating the impact of fake news on social media audiences; analyzing fake news patterns; and recommending ways to stop its circulation. To achieve these objectives, we follow a review-based research methodology encompassing scholarly articles and reports from sources including JSTOR, Taylor & Francis, MDPI, Google Scholar, and the WHO, covering the period from 2016 onwards. We employ the Uses and Gratification model to identify three key impacts of COVID-19 related misinformation on social media users: (1) an “infodemic” of health-related misinformation; (2) an increase in social media pastime; and (3) an increase in social, political, and religious conflicts. Several actions are proposed to limit the spread of fake news, involving entities such as government and health agencies, as well as social media companies.

The correlation study between EIA north crest in the south Asia region and strong earthquakes

Paying attention to the relationship between EIA signatures and earthquakes can be useful to further understand the earthquake anomalies and seismo-ionospheric coupling mechanism. Based on the GIM TEC data, the EIA north crest signature in the south Asia region was investigated for 92 M ≥ 6.0 earthquakes from 1999 to 2022. A running mean method was utilized to extract the anomalies potentially associated with earthquakes. It was found that before the strong earthquakes, the EIA north crest significantly moves equatorward, and the formation time of the crest appears earlier than that in normal days. The TEC strength of EIA north crest can both increase or decrease prior to earthquakes. The results in this study further imply that the abnormal electric field formed around the epicenter is potential the main channel of Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) mechanisms during the earthquake preparation period.

MiRNA and DNA analysis by negative ion electron transfer dissociation and infrared multiple-photon dissociation mass spectrometry

BackgroundThe use of simple and hybrid fragmentation techniques for the identification of molecules in tandem mass spectrometry provides different and complementary information on the structure of molecules. Nevertheless, these techniques have not been as widely explored for oligonucleotides as for peptides or proteins. The analysis of microRNAs (miRNAs) warrants special attention, given their regulatory role and their relationship with several diseases. The application of different fragmentation techniques will be very interesting for their identification. ResultsFour synthetic miRNAs and a DNA sequence were fragmented in an ESI-FT-ICR mass spectrometer using both simple and hybrid fragmentation techniques: CID, nETD followed by CID, IRMPD, and, for the first time, nETD in combination with IRMPD. The main fragmentation channel was base loss. The use of nETD-IRMPD resulted in d/z, a/w, and c/y ions at higher intensities. Moreover, nETD-IRMPD provided high sequence coverage and low internal fragmentation. Native MS analysis revealed that only miR159 and the DNA sequence formed stable dimers under physiological ionic strength. The use of organic co-solvents or additives resulted in a lower sequence coverage due to lesser overall ionization efficiency. NoveltyThis work demonstrates that the combination of nETD and IRMPD for miRNA fragmentation constitutes a suitable alternative to common fragmentation methods. This strategy resulted in efficient fragmentation of [miRNA]5- using low irradiation times and fewer internal fragments while ensuring a high sequence coverage. Moreover, given that such low charge states predominate upon spraying in physiological-like conditions, native MS can be applied for obtaining structural information at the same time.

Darien Gap Forested Jungles and Waterways (APDDGFJW) of Latin America and the Caribbean (LAC) in the Post-COVID 19 of the 21st Century

This paper deals with the identification of the Darien Gap as the main channel of continuous clandestine, illegal, undocumented and irregular migratory pathways of African Youths which caught our attention in the post-COVID 19 of the 21st Century with gross ambitions to get richer faster through the slogan of greener pastures with the majority giving off their lives ignorantly and embarrassingly to tilapias of the Mexican deep rivers in an attempt to cross to North American countries of United States and Canada. The end results was the untimely psychological tortures of their parents and sporadic internal crises of blaming even those who never contributed to such unwanted illegal movements but raising voices to educate on the dangers of un official migration both internally or externally. In fact the majority of the youths having such ambitions of illegal crossing of the Darien Gap are totally ignorant of the nature of the route which has been above the imagination of top ranking Engineers to open it to be more possible for vehicles to use. The hilly, mountainous, muddy, swampy, smugglers, kidnapping, ripping and all sorts of trafficking are characteristics of the Darien Gap which none of the agent involve in such illegal route can account to their victims. It is just certain that any of such irregular extra-continental travelling without passing through official diplomatic services which moderate bilateral relations can only be termed as above. It is also our findings that the clandestine pathway routes those using are passing is characterized with wild animals, dangerous human criminals of trafficking, bandits, muddy, dense forested, not motorable as even top engineers have not been able to successfully mapped out a good road that can be constructed with the Darien deadly jungle. Our inspirations were drawn from lecturing of Post-Graduate students on the question of International Migration and Black Diasporas around the World during which most of them were ......

Dynamics of Taylor bubble under chemical reaction enhanced mass transfer in minichannel

Taylor bubble dynamic characteristics of CO2 chemical absorption into MEA aqueous solution in a vertical minichannel were systematically investigated in this study. The generation, movement, and shrinkage of bubbles in the minichannel were visualized and monitored using a high-speed camera, and their dynamic behaviors were characterized by image analysis method. The effects of gas and liquid Re numbers and absorbent concentration on two-phase flow patterns, bubble generation frequency, initial bubble length, bubble length decrease rate, and bubble velocity were examined and analyzed. Results showed that chemical reaction-enhanced mass transfer hindered the bubble cap penetration into the main channel, and alleviated the bubble neck thinning, both effects inhibiting the bubble generation. A new Damköhler number (Da)-based correlation has been proposed to predict the initial Taylor bubble length, showing good prediction accuracy for experimental data in the literature using different absorbents. Results also showed that before the formation of sphere bubble at the end of absorption, an approximate linear relationship exists between bubble length decrease rate and bubble velocity, with the slop decided by chemical reaction rate that could be characterized by the Da number. Finally, a simple model has been developed to determine the effective channel length at a given operating condition, providing design guidelines for microchannel-based miniaturized CO2 absorbers.

New Channels for Recruiting Governors to the Regions of the Russian Federation

The relationship between the federal center and the subjects is built on the basis of a centralized personnel policy. Pursuing a specific goal, the federal center appoints the heads of the subjects. The article examines the main channels for recruiting governors to the regions, the nature of the appointments of the heads of the subject, their professional activities before taking office as the head of the subject. The results of the new policy of the federal center regarding the appointment of regional leaders and their main tasks for pursuing a balanced policy in relation to each subject are analyzed.

Digital economy, industrial structure upgrading, and residents' consumption: Empirical evidence from prefecture-level cities in China

In the context of promoting high-quality economic development, how to use digital technology to empower industrial transformation and upgrading, and then drive consumption growth, has become a critical issue that needs to be solved urgently. Based on the panel data of prefecture-level cities in China from 2011 to 2020, this paper has discussed the influence of the digital economy on residents' consumption and its internal mechanism. Theoretical analysis and empirical test results show that, firstly, the digital economy has a positive effect on residents' consumption, and this conclusion is still valid after the endogenous test and robustness test. Secondly, mechanism analysis results confirm that industrial structure upgrading is the main channel through which the positive mediating effect operates. Thirdly, the influence of the digital economy is only valid for rural areas rather than urban areas, and more significant for western regions than eastern and central regions, which indicates the development of the digital economy is beneficial to narrowing the consumption gap. Finally, the positive impact of the digital economy on residents' consumption is continuously strengthened with the upgrading of industrial structure, which is a significant non-linear characteristic of the marginal effect increasing. The above research conclusions can provide a theoretical basis for further improving the infrastructure of the digital economy, accelerating the integration of the digital economy with traditional industries, and building a consumer Internet.