Local Sources Research Articles

Multiscale CO Budget Estimates Across South America: Quantifying Local Sources and Long Range Transport

AbstractSouth America is a large continent situated mostly in the Southern Hemisphere (SH) with complex topography and diverse emissions sources. However, the atmospheric chemistry of this region has been historically understudied. Here, we employ the Multi‐Scale Infrastructure for Chemistry and Aerosols, a novel global circulation model with regional refinement capabilities and full chemistry, to explore the sources and distribution of the carbon monoxide (CO) tropospheric column in South America during 2019, and also to assess the effect that South American primary emissions have over the rest of the world. Most of the CO over South America can be explained either by non‐methane volatile organic compounds (NMVOC) secondary chemical production or by biomass burning emissions, with biomass burning as the main explanation for the variability in CO. Biomass burning in Central Africa is a relevant contributor to CO in all of the continent, including the southern tip. Biogenic emissions play a dual role in CO concentrations: they provide volatile organic compounds that contribute to the secondary CO production, but they also destroy OH, which limits the chemical production and destruction of CO. As a net effect, the lifetime of CO is extended to ∼120 days on average over the Amazon, while still being in the range of 30–60 days in the rest of South America.

Personal exposure monitoring of fine and coarse particulate matter using exposure assessment models for elderly residents in Hong Kong

This study investigated the determinants of personal exposures (PE) to coarse (PM2.5-10) and fine particulate matter (PM2.5) for elderly communities in Hong Kong. The mean PE PM2.5 and PM2.5-10 were 23.6 ± 10.8 and 13.5 ± 22.1 μg/m3, respectively during the sampling period. Approximately 76% of study subjects presented statistically significant differences between PE and ambient origin for PM2.5 compared to approximately 56% for PM2.5-10, possibly due to the coarse-size particles being more influenced by similar sources (road dust and construction dust emissions) compared to the PM2.5 particles. Individual PE to ambient (P/A) ratios for PM2.5 all exceeded unity (≥1), suggesting the dominant influences of non-ambient particles contributed towards total PE values. There were about 80% individual P/A ratios (≤1) for PM2.5-10, implying possible effective infiltration prevention of larger size particulate matter particles leading to dominant influences from the outdoor sources. The higher concentration of NO3− and SO42− in PM2.5-10 compared to PM2.5 suggests possible heterogeneous reactions of alkaline minerals leading to the formation of NO3− and SO42− in PM2.5-10 particles. The PE and ambient OC/EC ratios in PM2.5 (8.8 ± 3.3 and 10.4 ± 22.4, respectively) and in PM2.5-10 (6.0 ± 1.9 and 3.0 ± 1.1, respectively) suggest possible secondary formed OC from surrounding rural areas. Heterogeneous distributions (COD >0.2) between the PE and ambient concentrations were found for both the PM2.5 and PM2.5-10 samples. The calibration coefficient as the association between personal and surrogate exposure measure of PE to PM2.5 (0.84) was higher than PM2.5-10 (0.52). The findings further confirm that local sources were the dominant contributor to the coarse particles and these coefficients can potentially be used to estimate different PE to PM2.5 and PM2.5-10 conditions. A comprehensive understanding of the PE to determinants in coarse particles is essential to further reduce potential exposure misclassification.

Numerical Analysis of Broadband Noise Generated by an Airfoil with Spanwise-Varying Leading Edges.

Here, the single-target parameterization of alternatives to leading-edge noise is carried out using analytical models based on the Wiener-Hopf technique. Four leading-edge serration profiles with different frequencies, amplitudes, and phases are implemented to aid the understanding of sound suppression mechanisms. The effects of the serrated shape factor, wavelength, and amplitude are analyzed at tip-to-root ratios of 0.5, 1, and 2, respectively. An effective double-wavelength sinusoidal serration design can substantially reduce the noise emissions of 5.2 dB at h¯ = 2. Additionally, compared to single-wavelength serrations, an additional 1.47 dB noise reduction effect can be obtained by double-wavelength serrations under the appropriate design parameters. The surface pressure and phase distribution of different spanwise-varying leading edges indicate that the phase interference effect affected by source-radiated noise reduction is enhanced by this serration at the hills for serrations with a small curvature, and noise emission in the low-frequency band is more effectively suppressed. The sharper the serration is, the more conducive it is to a reduction in high-frequency noise. Nevertheless, the effectiveness of serrations is usually partially limited by the non-negligible trailing-edge self-noise. The sound source intensity of the root is decreased by the ogee-shaped serrations with a large curvature transition. A secondary noise reduction mechanism with a local source cut-off effect caused by nonlinearity is demonstrated.

Decision Support System version 1.0 (DSS v1.0) for air quality management in Delhi, India

Abstract. This paper discusses the newly developed Decision Support System version 1.0 (DSS v1.0) for air quality management activities in Delhi, India. In addition to standard air quality forecasts, DSS provides the contribution of Delhi, its surrounding districts, and stubble-burning fires in the neighboring states of Punjab and Haryana to the PM2.5 load in Delhi. DSS also quantifies the effects of local and neighborhood emission-source-level interventions on the pollution load in Delhi. The DSS-simulated Air Quality Index for the post-monsoon and winter seasons of 2021–2022 shows high accuracy (up to 80 %) and a very low false alarm ratio (∼ 20 %) from day 1 to day 5 of the forecasts, especially when the ambient air quality index (AQI) is > 300. During the post-monsoon season (winter season), emissions from Delhi, the rest of the National Capital Region (NCR)'s districts, biomass-burning activities, and all other remaining regions on average contribute 34.4 % (33.4 %), 31 % (40.2 %), 7.3 % (0.1 %), and 27.3 % (26.4 %), respectively, to the PM2.5 load in Delhi. During peak pollution events (stubble-burning periods or wintertime), however, the contribution from the main sources (farm fires in Punjab–Haryana or local sources within Delhi) could reach 65 %–69 %. According to DSS, a 20 % (40 %) reduction in anthropogenic emissions across all NCR districts would result in a 12 % (24 %) reduction in PM2.5 in Delhi on a seasonal mean basis. DSS is a critical tool for policymakers because it provides such information daily through a single simulation with a plethora of emission reduction scenarios.

Research on transient temperature rise characteristics of composite cylindrical roller bearings

Composite roller bearings have received extensive attention from bearing design engineers because of their good contact and running performance. According to the contact mechanical characteristics of composite cylindrical roller, a bearing heat generation power calculation model is established. Then, using the local heat source analysis method, and considering the heat conduction mode, the transient temperature solution model of bearings is established. The influence of filling ratio, radial force, angular velocity and roller numbers on the heat generation power and steady-state temperature of the bearing components is calculated and analyzed. The calculated results are in good agreement with the experimental results, which verifies the correctness of the model. The model can accurately predict the temperature distribution of bearings, providing new ideas and methods for temperature rise analysis, and laying the foundation for temperature analysis of bearings.

Business history without business: intermediation and China's pre-1949 cattle trade

Abstract China's cattle trade before 1949 is effectively invisible to historians. With no geographic center, few dominant firms, and little government oversight, cattle trade left behind no clear archive of sources, leaving scholars to the mercy of conjecture and episodic evidence. Combining insights from business and social history, we focused our attention on trade intermediation as the key to understanding the operations of a diffuse trade system. In the absence of a top–down archive, we composited hundreds of local sources on intermediation in cattle trade and remotely interviewed 80 former brokers. These sources revealed large numbers of individuated trade routes, which we break into three types: persistent supply, specialized demand, and resource circulation. Each type of trade called for distinct forms of intermediation with relatively little overlap between specialized networks. This recreation of China's cattle trade reveals a sophisticated market for animal labor that calls into question the direct causal link between imperialist resource extraction and rural immiseration, and suggests the utility of applying tools and perspectives of social history to other sorts of decentered commercial systems.

PEMBERDAYAAN MASYARAKAT INDRALAYA RAYAMELALUI INTRODUKSI TEKNOLOGI SOLAR DRYING BIJI LOTUS (Nelumbo nucifera) LIAR

The use of natural water resources in the surrounding area must be utilized optimally through local source diversification activities, especially in Indralaya Raya village, Indralaya District, Ogan Ilir Regency. Availability of lotus seeds is abundant especially during rainy season but has not been utilized optimally. In services program, the introduction of solar drying technology was carried out through outreach and assistance to Village residents, especially youth organizations and micro small medium enterprises (UMKM), regarding the application of technology used for the drying process of lotus seeds, so that the dried lotus seeds could be stored longer for further used, then the next activity continued with the processing of diversified flour products and their derivatives. The success of this activity has shown that the Indralaya Raya residents were enthusiastic about this service activity as shown by the activity achievement indicators. Socialization and assistance activities on the use of solar-powered dryers and the manufacture of flour products and their derivatives have had a positive impact on the Indralaya Raya village community in empowering the activities of youth organizations and UMKMs.

Socioeconomic Impacts of Climate Mitigation Actions in Greece: Quantitative Assessment and Public Perception

Appropriately designed and implemented climate mitigation actions have multiple co-benefits (yet some trade-offs cannot be excluded) that result in substantial social and economic value beyond their direct impact on reducing energy consumption and GHG emissions. Despite their wider acknowledgement by the research community, decision makers and the public have incomplete information on these multiple effects. This paper has a twofold objective: First, through analytical bottom-up approaches, it assesses, in quantitative terms, the macroeconomic effects and the public health benefits attributed to a variety of mitigation actions under consideration in the context of the Greek Energy and Climate Plan. Second, it investigates, through a social survey, how citizens perceive climate change and value these multiple impacts of mitigation actions, and to what extent they are willing to pay for them and support the adoption of policy measures aiming at the green transition of the Greek economy. We show that mitigation actions bring about significant health benefits, particularly in cities, and generate significant positive macroeconomic effects, particularly if mitigation actions focus on the decarbonization of the building sector and on the exploitation of local renewable sources. We also argue that most people do not realize that climate mitigation actions can have wider benefits for society, such as tackling energy poverty, improving public health, and creating new jobs. Unwillingness to pay tends to be the prominent attitude. People who are more reluctant to cover a part of the cost of environmental protection are less likely to perceive that climate change is one of the main challenges at global and national level and support the adoption of climate mitigation policies. In this context, the national strategy for climate change should focus on effectively informing and engaging the public in climate mitigation strategies, strengthening the public trust in government institutions, promoting mutually acceptable solutions with the local communities, and providing incentives for changing citizens’ behavior towards climate-related actions.

Classifying and quantifying decadal changes in wet deposition over Southeast and East Asia using EANET, OMI, and GPCP

South East and East Asia are regions which have undergone rapid economic development, contributing a significant amount of urban and biomass burning emissions. While the connections between emissions, deposition, and impacts on the Earth System are theoretically understood, they are observationally and ill-constrained, especially with respect to the effects of a changing climate and the Monsoon. This work shows the results of a new classification scheme and Asian-Wide monthly wet deposition product based upon 16 years of surface wet deposition observations and remotely sensed trace gas and precipitation measurements throughout South East and East Asia. Specific information corresponding to underlying driving and physical processes including in-situ processing, long-range transport, and local emission sources are all considered. Scientific findings are made specifically with respect to the increased impacts of urban-scale change, long-range transport, and enhanced deposition under moderate to low precipitation conditions. Previously accepted definitions of clean and polluted areas are challenged and updated based upon more detailed analysis of the observed physical and chemical relationships and simple models. The spatial and temporal distribution of the resulting modeled wet deposition is shown to impact the oceans more significantly, and regions of land not previously thought to be heavily impacted.

Strategi Optimalisasi Pendapatan Pajak Daerah Untuk Meningkatkan Kemandirian Keuangan (Analisis di Kota Pekanbaru)

This research aims to analyze the contribution of local taxes to Local Own Source Revenue (PAD) and to identify the level of fiscal independence of the region in Pekanbaru City. The research method used is secondary data analysis from the realization data of local taxes and PAD from 2018 to 2022 obtained from the Pekanbaru City Revenue Agency. The data is then analyzed using descriptive statistical techniques to identify trends in the contribution of local taxes to PAD and the level of fiscal independence of the region during this period. The analysis results show that the contribution of local taxes to PAD in Pekanbaru City ranges from 80% to 93% during this period, with an increasing trend every year. However, fiscal independence of the region is still in the category of "Towards Fiscal Independence," with PAD contributions ranging from 25% to 33% of the total Regional Revenue in the Regional Budget. The study concludes that although local taxes have become the main backbone for PAD in Pekanbaru, fiscal independence of the region needs to be strengthened with measures such as re-registering taxpayers and improving the efficiency of local tax management.

Untapped Opportunities in Additive Manufacturing with Metals: From New and Graded Materials to Post-Processing

Metal additive manufacturing (AM) is an innovative manufacturing method with numerous metallurgical benefits, including fine and hierarchical microstructures and enhanced mechanical properties, thanks to the utilization of a local heat source and the rapid solidification nature of the process. High levels of productivity, together with the ability to produce complex geometries and large components, have added to the versatile applicability of metal AM with applications already implemented in various sectors such as medicine, transportation, and aerospace. To further enhance the potential benefits of AM in the context of small- to medium-scale bulk production, metallurgical complexities should be determined and investigated. Hence, this review paper focuses on three significant metallurgical aspects of metal AM processes: in situ alloying, functionally graded materials, and surface treatments for AM parts. The current text is expected to offer insights for future research works on metal AM to expand its potential applications in various advanced manufacturing sectors.

Genome-wide sequencing reveals geographical variations in the thermal adaptation of an aquaculture species with frequent seedling introductions

Climate change and human activity are essential factors affecting marine biodiversity and aquaculture, and understanding the impacts of human activities on the genetic structure to increasing high temperatures is crucial for sustainable aquaculture and marine biodiversity conservation. As a commercially important bivalve, the Manila clam Ruditapes philippinarum is widely distributed along the coast of China, and it has been frequently introduced from Fujian Province, China, to other regions for aquaculture. In this study, we collected four populations of Manila clams from different areas to evaluate their thermal tolerance by measuring cardiac performance and genetic variations using whole-genome resequencing. The upper thermal limits of the clams showed high variations within and among populations. Different populations displayed divergent genetic compositions, and the admixed population was partly derived from the Zhangzhou population in Fujian Province, implying a complex genomic landscape under the influence of local genetic sources and human introductions. Multiple single nucleotide polymorphisms (SNPs) were associated with the cardiac functional traits, and some of these SNPs can affect the codon usage and the structural stability of the resulting protein. This study shed light on the importance of establishing long-term ecological and genetic monitoring programs at the local level to enhance resilience to future climate change.

Assessing the effects of significant activity changes on urban-scale air quality across three European cities

This study investigates the effects of significant activity changes on air pollutant concentrations across the three European cities Hamburg, Liège, and Marseille and focuses on the effects of COVID-19 lockdown measures as a case study for such significant activity changes. To identify such effects, this study utilizes urban-scale chemistry transport modeling, embedded in regional-scale Chemistry Transport simulations. The outcomes underscore the significance of considering local conditions and emissions sources, as variations between urban and regional simulations demonstrate. Notably, lockdown regulations yield the most substantial impact in Marseille due to its dense road traffic and port area, with Liège following suit, primarily influenced by regional air quality alterations. Conversely, Hamburg exhibits lower mean changes, attributed to its widespread urban structure. Analysis of modeled exceedances of limit values reveals significant reductions, particularly in areas of urban and road land use. These findings contribute valuable insights into the efficacy of significant activity changes, such as lockdown measures, in mitigating air pollution, underlining the importance of tailored strategies for emission reduction in urban environments.

Waste discharge concentration and quadratic thermal radiation influences on time-dependent nanofluid flow over a porous rotating sphere

The nature of waste discharge concentration on time-dependent nanofluid flowing over a rotating sphere is examined in the conducted research. The linear and quadratic radiation influences are considered in the energy transport equation. The flow generation occurs due to a sphere’s revolution with time-dependent angular velocity. The term external pollutant concentration is modeled in the concentration equation. Titanium dioxide ( Ti O 2 ) nanoparticles are inserted into base-liquid water ( H 2 O ) . Similar variables are reported for the conversion of the problem. The converted problem is computed through the Runge–Kutta–Fehlberg (RKF) scheme. The study outcomes obtained from a numerical scheme are presented with the help of graphs. The rise in the linear and quadratic thermal radiation factors will enhance the thermal profile. Improvement in local pollutant external source and external pollutant source parameters will improve the concentration profile. The mass transfer rate will improve by adding the solid volume fraction and escalated values of local pollutant external source constraints.

Evaluation and Performance Analysis of Liquefied Petroleum Gas Cylinders

This paper presents the experimental results of the tensile, bending, hardness, hydrostatic testing, and microstructural properties of liquefied petroleum gas cylinders from local sources. The burst pressure and fracture sites were also investigated. In addition, know how LPG cylinders are compliant with ISO 4706 requirements as per standard to get approval and acceptance. The tests were performed on three samples (C1, C2, and C3), and all the tests were according to the specification. Tensile testing was carried out at room temperature (23C°) as per ISO 6892-2016. Tensile test specimens with a gauge length of 50 mm were prepared from the sidewall of cylinders. The equipment used is built up around a 250 KN maximum capacity of (Instron Servo-Hydraulic Testing Machine Model 1332). At the same time, micro-hardness testing was carried out as per ASTM A384. Diamond indenter (pyramid) with a face angle of 136° was used. During testing (1kg) load was applied on the sample with a dwell time of 15 seconds. As for bending tests were carried out in accordance with ISO 7438 for all cylinders to evaluate their welding qualities. The results of microstructural characterization show that the carbon content for all samples averaged ~ 0.067 wt.% and manganese ~ 0.46 wt.% and the microstructure was largely ferritic. The tensile strength of the parent metal showed that LPG gas cylinders recorded high tensile strength of ~ 418 MPa on average, yield strength of ~ 291 MPa on average, a % elongation 26.6 (for parent metal), the tensile strength of ~ 449 MPa as average, yield strength of ~ 314 MPa as average, % elongation 32 (for weld metal) and hardness of ~ 143 (kg/mm2) as average by Vickers scale. Moreover, in the hydrostatic pressure test, the computer controlled electro-hydraulic servo pressure test machine was used. The results of the hydrostatic pressure test were as follows, pressure burst (BP) 103 bar, nominal hoop stress 528 MPa, volumetric expansion 25%, hydrostatic extend ratio 3.9%, sites of failure exist out of welding, and finally no fragmentation observed regarding to fracture types. All samples tested exhibited high resilience to crack propagation which showed ductile fracture after burst and tensile tests.

Black carbon and PM0.49 characterization in manila north harbour port, Metro Manila, Philippines

Globalization and industrialization have increased the shipping activities in Metro Manila. This increase in economic activity has contributed to the exacerbation of atmospheric particle pollution, particularly black carbon (BC) and particulate matter (PM). In this study, PM0.49 and BC were characterized in North Harbour in Metro Manila, Philippines. Using a multiple-split high-volume cascade impactor, PM0.49 and PM2.5 were collected from December 2019 to January 2020. Equivalent BC (eBC) mass concentrations were measured using an aethalometer (AE33, Magee Scientific) while chemical analysis was also performed using ion chromatography. The PM0.49 was tested for its morphological and mineralogical characteristics. Daily analysis showed no significant difference between the weekday and weekend pollution concentration in the port, although mean concentration (70 ± 21 μg/m3) exceeds that of the 24-hr Philippine air quality guideline value of 50 μg/m3 for PM2.5 concentrations. The particle compositions of PM0.49 are mostly from Si-rich particles and Pb-rich particles. High variability was observed for Mg, Si, Ca, Fe, Cd, Zn, Mn, S, Cl, V, and Cr heavy metals. The carbonaceous species with the highest concentration was organic carbon (OC) (33 ± 9 μg/m3) followed by BC (16 ± 3 μg/m3) and eBC (12 ± 3 μg/m3). An analysis of the ionic species showed SOX and NOX emissions as the primary ions, which are mostly related to ship emissions while the mineralogical analysis showed that soot particles are the main composition of the particles. Overall, the pollution assessment showed that North Harbour is polluted with heavy metals but within the Philippine air quality pollutant standard. In brief, the results of this study suggest that atmospheric pollution in the study site was mostly caused by local anthropogenic sources, particularly vessel emissions. The researchers suggest that a longer study period be conducted to further assess the seasonal variation of atmospheric particle pollution in North Harbour, Metro Manila.

Autonomous Nanorobots as Miniaturized Surgeons for Intracellular Applications.

Artificial nanorobots have emerged as promising tools for a wide range of biomedical applications, including biosensing, detoxification, and drug delivery. Their unique ability to navigate confined spaces with precise control extends their operational scope to the cellular or subcellular level. By combining tailored surface functionality and propulsion mechanisms, nanorobots demonstrate rapid penetration of cell membranes and efficient internalization, enhancing intracellular delivery capabilities. Moreover, their robust motion within cells enables targeted interactions with intracellular components, such as proteins, molecules, and organelles, leading to superior performance in intracellular biosensing and organelle-targeted cargo delivery. Consequently, nanorobots hold significant potential as miniaturized surgeons capable of directly modulating cellular dynamics and combating metastasis, thereby maximizing therapeutic outcomes for precision therapy. In this review, we provide an overview of the propulsion modes of nanorobots and discuss essential factors to harness propulsive energy from the local environment or external power sources, including structure, material, and engine selection. We then discuss key advancements in nanorobot technology for various intracellular applications. Finally, we address important considerations for future nanorobot design to facilitate their translation into clinical practice and unlock their full potential in biomedical research and healthcare.

Time-reversed electromagnetic fields in anisotropic media.

Electromagnetic time reversal is commonly used for field imaging and focusing. This Letter builds upon the concept of the time-reversal cavity, which constitutes the main theoretical framework of time reversal theory. We study the behavior of the fields using modern methods of mathematical physics involving Colombeau generalized functions. This approach allows for a direct expression of time-reversed electric and magnetic fields in anisotropic time-reversal-invariant and nonreciprocal media. Moreover, the results hold for any arbitrary localized source and can readily be applied beyond the dipole approximation. Finally, a general result allows the prediction of the quality of focusing of the time-reversed fields as a function of the electrical permittivity and the magnetic permeability tensors in homogeneous anisotropic media, which contributes to the understanding of time reversal in complex media such as super-resolution enabling metamaterials.

Cretaceous to early Paleogene sediment provenance transition from continental to magmatic arc systems in the Northwestern Pacific Region

Unraveling the Paleo-Kuril Arc's origins is key to understanding northwest Pacific tectonics. The Paleo-Kuril Arc is viewed as an intraoceanic arc from trench subduction between the Izanagi and Pacific Plates. Alternatively, several studies suggest the Paleo-Kuril Arc as a continental magmatic arc, hypothesizing the existence of a mid-oceanic ridge and Paleogene subduction, placing the Paleo-Kuril Arc near the Okhotsk Block's southern edge. This study clarifies these hypotheses, previously clouded by limited geochronological data on deposits in the Paleo-Kuril Arc. We conducted U–Pb dating to examine the origins of detrital zircons from the Cretaceous–Paleogene Tokoro and Nemuro Belts of the Paleo-Kuril Arc. Cluster analysis, merging new and existing data, identified two unique detrital zircon age clusters. The abundance of Precambrian zircons in Cretaceous–Paleocene Paleo-Kuril Arc sandstones (Type 1 Cluster) suggests a continental magmatic origin, supporting the ridge subduction model. However, an early Eocene shift to a consistent local volcanic source (Type 2 Cluster) highlights a significant provenance change. This geochronological evidence, indicating a separation from continental sources, calls for further research to decode the simultaneous development of sediment sources in different geological belts, potentially tied to the ridge subduction event.

Challenges in Obtaining and Seeking Information Among Breast Cancer Survivors in an Asian Country: a Qualitative Study.

Breast cancer survivors on adjuvant endocrine therapy (AET) have distinct information-seeking experience compared to those in the diagnosis and intensive treatment phase. This study aimed to understand the challenges in obtaining and seeking information among Malaysian breast cancer survivors. We conducted semi-structured, one-to-one interviews among patients using AET from two hospitals and a local cancer organization. Interviews were conducted until theme saturation was achieved (N = 25). Interviews were de-identified, transcribed verbatim, and analysed using thematic analysis. To ensure rigor, coding was conducted through regular discussions between two researchers and the findings were shared with several participants after analysis was completed. Three main themes were identified: limitations in the healthcare system, pitfalls of seeking information online, and limited information from local sources. The participants perceived that their information needs were not met by their healthcare providers and sought information on the Internet to complement their information needs. However, they were faced with risks of misinformation, information overload, and unethical promotion of health products. Those with limited English proficiency had difficulties in accessing quality information, and suggested that there should be more content created by local health advocates in local languages, with information that is tailored for local cultures. As the Internet has become an important medium of health education, healthcare providers and patients should be equipped with the skills to share and search for information online. Digital health literacy needs to be incorporated in patient education modules to create a more informed and empowered patient community.