Air Load Research Articles

Experimental, numerical and optimization investigation of sandwich structures with 3D-printed sacrificial core under explosive loading

Sandwich panel structures are widely used in aerospace, marine, and automotive applications due to their high stiffness, high strength-to-weight ratio, good vibration damping, and thermal conductivity. The present study investigates the response of 3D printed polylactide acid (PLA) honeycomb structures when used as a crushable core with a protective metal coating in order to analyze the extent of damage and deformation of the center of the back sheet. This research is based on experimental testing and finite element simulation. The purpose of this study is to investigate the effect of three parameters of sandwich panel core, including filling density of the sacrificial core, 3D printer nozzle thickness, and the geometry of printed cells on the strength of sandwich panel under explosive loading. In this study, the effect of these three parameters is investigated at the same time, and finally, the optimal state of these three parameters that leads to the least displacement of the center of the back sheet is introduced. At first, a sandwich structure with a honeycomb core was made by a 3D printing machine, and the filling density of the core was 13 %. Then this set was subjected to explosive loading in open air with C4 explosive and the displacement of the center of the back sheet was measured. Further, considering the cost of experimental tests, the conditions of this test were simulated by the finite element code in LS-DYNA software, and the results of the displacement of the center of the back sheet were verified by experimental testing. In the following, Design-Expert software was used to check the three parameters of filling density, geometry of cells and thickness of the 3D printer nozzle at the same time. Finally, to verify the value obtained for the optimal state, the finite element simulation and experimental test were performed by placing the input parameters of the optimal state and the results were compared.

Blast resistance analysis of butterfly-like reentrant circular honeycomb sandwich structure

Negative Poisson honeycomb has great potential in the field of protection against explosive shock due to its unique tensile expansion characteristics and excellent energy absorption capacity. However, there are limitations in the types and performance enhancement of the current negative Poisson honeycomb sandwich structure (HSS), so to further improve the blast resistance of conventional HSS and reduce the mass of the structures, a butterfly-type reentrant circular HSS is designed in this paper. In this analysis, the JC constitutive model related to the mechanical properties of AL-6XN304 alloy steel was used for simulation, and the explosion load was applied to the sandwich structure using the CONWEP loading mode in ABAQUS, and its explosion process was analyzed numerically in detail. Explosive simulation of square-core HSS is first performed, and the precision of the numerical model is verified by comparing it with the experimental result in the existing literature. Secondly, the dynamic response of the imitation butterfly-type HSS under air loading was investigated, and the blast resistance performance of this structure was compared with that of four HSSs under the same air loading. The effects of explosive mass, cell thickness, cell wall radius, and cell length parameters on the blast resistance of imitation butterfly-type reentrant circular sandwich structure were also explored. Findings indicate that the dynamic response of the butterfly-like reentrant circular HSS is divisible into three distinct phases: core compression, overall deformation, and equilibrium vibration. Compared with the square, circular, reentrant hexagonal, and star HSSs, the center displacement of the front panel of the structure is 22.4, 20.2, 8.8, and 23.0% lower, respectively, and the center displacement of the rear panel is 24.4, 20.6, 7.1, and 8.2% lower, respectively. In addition, the central area of the structure is also the lowest deflection. Therefore, the butterfly-like reentrant circular HSS has the best explosion resistance. The butterfly-like reentrant circular HSS of the front and rear panel deflection and the displacement at the center point escalates as the explosive mass grows, diminishes with the thickening of the cell wall, lessens as the radius of the cell wall shrinks, and lessens as the cell length shortens, the blast resistance of the structure can be further improved.

Decoupling exhaust and return vents of supply momentum-driven stratified thermal environment with reinforced supply air jet entrainment from occupied zone

The supply momentum-driven stratified thermal environment created by advanced air distribution is a promising solution for sustainable and livable indoor environments. This study proposes a strategy to decouple the exhaust and return air for the supply momentum-driven stratified thermal environment. Experimentally validated Computational Fluid Dynamics simulations are used to verify the effectiveness of the strategy regarding energy efficiency improvement in a stratum-ventilated office. The proposed decoupled strategy positions the return vent below the exhaust vent and above the supply vent. The proposed decoupled strategy has two mechanisms for energy efficiency improvement, i.e., 1) reducing the cooling load of return air by lowering return air temperature relative to exhaust air temperature, and 2) advancing the airflow pattern with improved cooling efficiency of the occupied zone by reinforcing and suppressing the entrainments of the supply air jet from the occupied zone and the upper zone, respectively. The advanced airflow pattern reduces the cooling loads of both return air and fresh outdoor air and increases the Coefficient of Performance. Decreasing the height of the return vent strengthens Mechanism 1, but nonmonotonically affects Mechanism 2. By properly determining the height of the return vent, results show that the proposed decoupled strategy saves energy by 13.5% and 11.9% in thermally neutral and slightly warm environments, respectively. This study contributes to advancing air distribution for energy saving with thermal comfort.

Indoor air bacterial quality and associated factors in prison inmate cells of East Hararghe Zone and Harari Regional State, Eastern Ethiopia.

Bacterial indoor air load refers to the level of bacteria within and around dwellings and other structures. Pathogens, bacterial cell fragments, and bacterial organisms' byproducts can all pose major issues indoors, especially in prison inmate cells. However, there is lack of data on bacterial load and contributing factors in the East Hararghe zone and Harari regional state. The lack of studies on microbiological indoor air quality in prisons with contributing factors will therefore be filled by this investigation. The study aimed to assess bacterial indoor air load and contributing factors in prison inmate cells from October 1 to October 30, 2020. An institutional cross-sectional study was employed. All of the prisons in the East Hararghe zone and the Harari regional state served as the study's and source population. 62 prison cells were used in the investigation. Samples were obtained using the passively settling plate technique. The data were evaluated through the use of SPSS statistical software, Excel, and the statistical procedures of ANOVA, correlation, and chi-square test. The maximum and minimum bacterial loads, were recorded at 8:00 am (3027 CFU/m3) and 2:00 pm (1048 (CFU/m3) respectively. The correlation between the temperature and bacterial load was strongly positive (r = 0.680, p = 0.047), and the correlation of the moisture content and bacterial load was strongly negative (r = -0.671, p = 0.039). The levels of bacteria were higher than the guideline (2000 CFU/m3). While the relative humidity of indoor air was negatively correlated with bacterial load, temperature and bacterial load were significantly positively correlated. Harari regional state and East Hararghe zone prison commissions should be alarmed to alleviate these problems. The building standards need to be completely updated to the latest standards.

Determination and analysis of compensation capacitor for a robust distance-variable wireless power transfer system

Wireless power transfer (WPT) systems have been widely adopted for full autonomy in various fields due to their convenience. However, changes in the air gap between the Tx and Rx coils significantly affect efficiency. To overcome this challenge, this paper introduces the determination of a compensation capacitor for a distance-variable WPT system that is robust in varying air gap conditions. The proposed method was verified using theoretical analysis, simulation, and experimental measurement. The electrical circuit was modeled using a T-equivalent model in a series–series (SS) topology to calculate power transfer efficiency (PTE). Specifically, compensation capacitors were analyzed at distances of 10, 30, and 50 mm, considering different self-inductance values. These results are compared against varying load resistances to demonstrate the effectiveness of the proposed approach. Additionally, the PTE drop ratio was defined to facilitate comparison. The results show that the PTE drop ratio for the compensation capacitor at the farthest distance was consistently smaller than that for the capacitor at the nearest distance under varying air gaps and load resistances. In this research, the difference in the PTE drop ratio between 10 and 50 mm was measured, demonstrating that determining the capacitor at the farthest distance reduces the PTE drop ratio across a range of operational conditions.

Integrated LCC-LCC Topology for WPT System With CC Output Regarding Air Gap and Load Variations

Integrated LCC-LCC Topology for WPT System With CC Output Regarding Air Gap and Load Variations

Exergy and Energy Analysis of Forced Convective Thin-layer Solar Drying of Tiger Nuts (Cyperus esculantus L.)

Aims: To study the exergy and energy analysis for thin-layer solar drying of tiger nuts; and also to determine the drying kinetics for the thin-layer solar drying of tiger nuts. Study Design: Yellow variety of tiger nuts were dried in a forced convection solar dryer to determine the exergy and energy indices. Place and Duration of Study: Federal University of Technology, Owerri, Nigeria between October, 2022 to March, 2023. Methodology: The experiment was conducted at three different air velocities of 1.5, 2.5, and 3.5 m s-1 and two different loads of 70 and 140 g. The tiger nuts were dried from average initial moisture content of 52% (wb) to final moisture content of 10.2% (wb), at an average temperature range of 50.5 to 51.2 ºC. Energy utilization, exergy loss rate, exergy efficiency, improvement potential, and sustainability index were determined. Results: The results of energy utilization, exergy loss rate and improvement potential ranged from 2.1 to 5.09 W, 0.25 to 0.93 W and 0.08 to 0.54 W respectively; however, these values increased with increasing air velocities and loads. The results of exergy efficiency and sustainability index ranged from 41.8 to 68.49% and 1.72 to 3.17 respectively; these values increased with decreasing air velocities and loads. Graphical plots of moisture content with drying time showed that the moisture content of the tiger nuts decreased with increasing drying time. The characteristic nature of the curve is indicative of the fact that there was an initial higher rate of drying, which gradually declined with drying time. The results also showed that the drying rates of the tiger nuts ranged from 6.03 to 8.44 %MC/hr; and these values varied with the different air velocities and loads. Conclusion: The results from this research will serve as a guide in reduction of energy costs for the optimum design of convective dryers.

Quantitative and qualitative assessment of airborne microorganisms during gross anatomical class and the bacterial and fungal load on formalin-embalmed corpses

Mold growth on body donations remains an underreported yet serious issue in anatomical teaching. Bacterial and fungal growth pose health risks to lecturers and students, alongside with ethical and aesthetic concerns. However, limited information exists on the presence of bacteria and fungi on body donations and their underlying causes. To investigate the potential impact of airborne germs on body donation contamination, we conducted indoor air measurements before, during, and after our anatomical dissection course, with outdoor measurements serving as a control. Tissue samples from the dissected body donations were collected to assess the germ load, with qualitative and quantitative microbiological analyses. Air samples from the dissection hall contained no fungi, but various fungal species were identified in the adjacent stairways and outdoors which implies that fungal occurrence in the dissection hall air was independent of lecturers’ and students’ presence. Moreover, our results indicate that adequate ventilation filters can effectively reduce indoor fungal germs during courses, while the bacterial load in room air appears to increase, likely due to the presence of lecturers and students. Additionally, the tissue samples revealed no bacterial or fungal germs which implies that our ethanol-formalin-based embalming solution demonstrates an effective long-term antimicrobial preservation of corpses.

Fatigue and corrosion‐fatigue behavior of the β‐metastable Ti‐5Al‐5Mo‐5V‐3Cr alloy processed by laser powder bed fusion

AbstractWe performed rotating bending tests and axial (tension‐compression) load‐increase and constant amplitude high‐cycle fatigue tests in air and Hanks' balanced salt solution (HBSS) on the β‐metastable titanium alloy Ti‐5Al‐5Mo‐5V‐3Cr, processed by laser powder bed fusion (LPBF‐M), solution‐treated and aged, and shot‐peened. Rotating bending loading in air revealed a strong influence of process‐induced flaws on fatigue endurance. Especially in the high‐cycle fatigue range and the transition region, the stochastic distribution of the flaws and flaw sizes led to a high scatter of the number of cycles to failure. The axial load‐increase tests yielded a good fatigue life estimation, with a negligible difference between air and HBSS. The cyclic deformation behavior in HBSS was also strongly influenced by the local microstructure and defect distribution, and, thus, by crack formation and propagation. Plastic deformation and microcrack growth interact, and their relative amount resulted in different progressions of the plastic strain amplitude over the number of cycles for different specimens. Changes in the free corrosion potential and the corrosion current were highly sensitive indicators for fatigue‐induced damage on the rough surfaces, which was correlated to the microscopic examination, fracture surface features, and the fatigue crack development.

Pengaruh Angin Terhadap Tata Letak dan Jumlah Sekrup Konstruksi Baja Ringan Berdasarkan SNI-7971- 2013

Light weight steel material has experienced rapid development in the construction. However, there are still many costruction failures on light weight steel, resulting in cost loss. The failure of light steel structures often occurs at the connections. The connection tool on milld steel is usually using a self-drilling screw. The research location is at Aceh One Stop Integrated Service and Investment Service Building (DPMPTSP) Aceh. The problem in this study is the placement and number of screws on the lightweight steel roof structure in the field which is carried out for each member according to the code, and the effect of wind load on the placement and number of screws on the lightweight steel roof structure. This study aims to determine the effect of the placement and number of screws on the lightweight steel roof structure. The scope of this research of problems including the placement and number of screws on the lightweight steel roof structure. The standars used in the design of light steel structures in this study is SNI 7971 2013 and the loading planning standars using SNI 03 1727 1989. Calculation steps using the LRFD method for steel structure design regulated in SNI 03 1729 2002. Based on the results, it is obtained that the number and placement of the screws in the field are different from those obtained in the calculation. From the calculations, it is obtained from the recapitulation, dead loads with a maximum value of 123.07 kg, live loads with a maximum load of 30.1 6 kg, and for compressed air and suction loads with a maximum load of 180 kg. the maximum design force value is 1241.33 kg and the screws bearing resistance value is 256.752 kg. the number of screws is obtained where the the value of the design force is divided by the value of the bearing resistance, on each member obtained 1screw, 2 screws, 3 screws, 4 screws, and 5 screws. Whilst it is found for each member in the field using 3 screws.

Air cargo transportation, loading, and phase-based maintenance service scheduling in demand channel routes

The article proposes an approach for modeling and solving the air cargo transportation, loading, and phase-based maintenance scheduling problems within demand channels. Demand channel transportation presents unique challenges to meeting the earliest pickup and delivery requirements during emergencies. The complexities in transportation involve issues with airport-aircraft compatibility, fleet selection, task assignments, route construction, and effective loading–unloading procedures. The challenges include coping with flight connections due to airport-aircraft compatibility, dealing with limited refueling and maintenance facilities, and swiftly adapting to unforeseen maintenance events by identifying and utilizing available fleets. In this context, the article delineates a demand channel route planning strategy that considers airport-aircraft compatibility, task integrity, priority, partial refueling strategy, and maintenance schedules spanning short to long-haul phases. Formulated as a Mixed Integer Linear Programming (MILP) problem, the solution employs a novel acyclic route construction procedure within a fuel-conscious network. We propose an insertion heuristic with multi-faceted algorithmic interconnections for producing a near-optimal solution suitable for real-world applications. Our insertion procedure has been shown to have very high computational performance, with an average 1.32 percent optimality gap. It can be scaled up to the most critical cargo mission, with up to 190 ports, 95 aircraft, and 380 tasks.

Design and Implementation of a Hardware-in-the-Loop Air Load Simulation System for Testing Aerospace Actuators

This paper presents the design and implementation of the hardware and control strategies of an electrohydraulic air load simulation system for testing aerospace actuators. The system is part of an Iron Bird, which is an energy management research platform developed in collaboration between Saab AB and Linköping University. The purpose of the air load system is to provide realistic forces on the test object through the integration of a flight simulator for full mission evaluation. The challenge with electrohydraulic force control is tackled by increasing the hydraulic capacitance from increased load cylinder dead volumes, together with a feed-forward link based on accurate modelling of the test object and load system by adopting an optimisation routine to find model parameters. The system is implemented for both an electromechanical and servohydraulic actuator as test objects with different performance requirements. The control design is based on nonlinear and linear modelling of the system, and experimental test data are used to tune the models. Finally, test results of the air load system prove its force-tracking performance.

Development of Static Test Equipment and a System for Lever-Loaded Air Springs

In light of the heavy load applied by traditional air spring test equipment and its complex structural system design, a lever-type torque loading air spring test system is designed. It adopts the principle of Chinese scales to apply the load on the air spring in the form of proportional amplification, which can apply a simulated load on the air spring of 500–800 kg, using the vertical sliding shaft as the transverse limit to make the air spring elongate and compress by 280 mm in the longitudinal direction. The measurement and control system of the test equipment is then developed based on the LabVIEW platform, and the required sensors are selected and installed. The system can achieve real-time data acquisition of the air pressure, load, height and other parameters of the air spring and air spring charging and discharging control. Following the debugging of the function of the test equipment, the function of each subsystem is normal and able to meet the requirements of air spring characteristic and pressure tightness tests. For small spaces, such as laboratories, by reducing the installation of hydraulic and other oil source systems, avoiding the use of large mass blocks to simulate the loading of air spring loads and optimizing the complex installation and debugging process, this miniaturized design for air spring test equipment has benefits for practical applications.

Pengaruh Angin Terhadap Tata Letak dan Jumlah Sekrup Konstruksi Baja Ringan Berdasarkan SNI-7971- 2013

Light weight steel material has experienced rapid development in the construction. However, there are still many costruction failures on light weight steel, resulting in cost loss. The failure of light steel structures often occurs at the connections. The connection tool on milld steel is usually using a self-drilling screw. The research location is at Aceh One Stop Integrated Service and Investment Service Building (DPMPTSP) Aceh. The problem in this study is the placement and number of screws on the lightweight steel roof structure in the field which is carried out for each member according to the code, and the effect of wind load on the placement and number of screws on the lightweight steel roof structure. This study aims to determine the effect of the placement and number of screws on the lightweight steel roof structure. The scope of this research of problems including the placement and number of screws on the lightweight steel roof structure. The standars used in the design of light steel structures in this study is SNI 7971 2013 and the loading planning standars using SNI 03 1727 1989. Calculation steps using the LRFD method for steel structure design regulated in SNI 03 1729 2002. Based on the results, it is obtained that the number and placement of the screws in the field are different from those obtained in the calculation. From the calculations, it is obtained from the recapitulation, dead loads with a maximum value of 123.07 kg, live loads with a maximum load of 30.1 6 kg, and for compressed air and suction loads with a maximum load of 180 kg. the maximum design force value is 1241.33 kg and the screws bearing resistance value is 256.752 kg. the number of screws is obtained where the the value of the design force is divided by the value of the bearing resistance, on each member obtained 1screw, 2 screws, 3 screws, 4 screws, and 5 screws. Whilst it is found for each member in the field using 3 screws.

Temporal Variation and Phylogeny of Air and Surface Microflora in Relation to Occupancy Patterns in a Higher Education Institution (HEI)

People not only inhale life-sustaining oxygen but also traces of bacteria and even inanimate surfaces introduce microorganisms to one’s bodies. However, the diversity and richness of bacterial communities both indoor and outdoor in a Philippine HEI in relation to human occupancy patterns remain relatively unexplored. Hence, the study aimed to bridge this gap. Microflora were collected using settle plates and swabbing method and identified by comparing their 16s rRNA gene amplicons using the Basic Local Alignment Tool. Several isolates were found to have biological implications in health (e.g. Staphylococcus haemolyticus and Bacillus clarus) and biotechnology (e.g. Rhodococcus pyridinivorans and Bacillus altitudinis). The phylogeny of samples exhibited close cohesion from the genus level, hence forming monophyletic taxa – under the classes Bacilli, Gammaproteobacteria, and Actinomycetes. Furthermore, statistical results established the significant relationship between indoor air and outdoor surface microbial load with the volume of occupants, as opposed to outdoor air and indoor surfaces. The analysis also revealed a strong correlation between the volume of occupants and indoor air microbial concentration (p = 0.002, R = 0.998), likewise in the case of indoor and outdoor surface bacterial contamination (p = 0.036, R = 0.664). Additionally, there was a significant difference in the indoor and outdoor air microbial load following human occupancy patterns in the area (p = 0.018). Findings of the study provide a foundation for understanding air and surface-borne flora, as well as a basis for the enhancement of health and safety standards for building inhabitants.

Air-conditioning load characteristics and grey box predicting model in subway stations

With the continuous expansion of metro, energy conservation of air-conditioning system in subway stations draws the attention of the whole world. Most of the researches are focused on improving the energy efficiency of the system, while the load characteristics of subway stations are paid little attention. The inaccurate load prediction in the designing of air-conditioning system results in redundancy and low operating efficiency. Therefore, accurately predicting the air-conditioning load is crucial for energy saving in subway stations. In this paper, an innovative three-stage subway air-conditioning load test method was proposed and implemented in nine subway stations in Qingdao. Based on the test data, the special air-conditioning load characteristics of subway stations as underground buildings were analyzed. The results showed that electrical equipment load accounted for the largest part, reaching 53.7 %, while only 42 % of the equipment power was converted into air-conditioning load. The positive role of the envelope should not be ignored, especially in the case of entrance and exit walls, which bore almost all of the fresh air load. Based on the three-stage test, a grey box model was established and the error was validated to be within 6 %. With this model, the load of air-conditioning system can be calculated by inputting passenger flow, power of electrical equipment and public area. This paper provides a reference for the design and operation of air-conditioning system in subway stations.

Experimental studies of the influence of hydrogen and sulfur on sulfide-corrosion destruction under tension of pipelines

For the first time, comprehensive experimental studies of the influence of hydrogen and sulfur on sulphide stress corrosion cracking (SCR) of pipe steels in a corrosive-aggressive environment of NACE were carried out. In the research, experimental steels of the 06G2BA and 08KHMCHA brands, which are widely used in the construction of pipelines for various purposes, were used an analytical system (analyzer of non-stationary processes – ANP) was developed and tested in laboratory conditions, into which the installation for tests on corrosion-mechanical cracking under stress was integrated. For the first time, comprehensive experimental studies of pipe steel samples of grades 06G2BA and 08KHMCHA under the influence of sulfur and hydrogen were carried out, which made it possible to develop an understanding of the mechanisms of SCDS (sulphide-corrosion destruction under stress) and HID (hydrogen-initiated destruction). For the first time, experimental studies of the corrosion kinetics of 06G2BA and 08KHMCHA steels were carried out depending on the duration of the tests in the NACE model environment, while three periods of the formation of corrosion products were determined. It was found that sulfur and hydrogen, which are dissolved in test pipe steels, have a strong influence on the growth rate of corrosion cracks of SCDS, which made it possible to determine the optimal content of sulfur and hydrogen in steel 06G2BA. It is shown on the basis of the results of experimental studies that to ensure high crack resistance of pipe steels under conditions of static and cyclic loads both in air and in conditions of corrosive-aggressive environments, the sulfur content should not exceed 0.015-0.020%, and the dissolved hydrogen content should not exceed 2-3 ppm . The obtained results make it possible to improve pipe steels in the process of their smelting at metallurgical enterprises thanks to the use of economical modification with niobium, chromium, cerium and other impurities, which contribute to the fragmentation of the structure and reduce the content of non-metallic inclusions and harmful impurities.

Performance study of a heat pump fresh air unit based on desiccant coated heat exchangers under different operation strategies

Fresh air system is getting more and more important nowadays. The heat pump fresh air system based on the desiccant coated heat exchanger (DCHE) that can handle the latent and sensible load of fresh air efficiently has a large energy saving potential. To improve the performance of the heat pump fresh air system based on DCHE, in this paper, a control system based on PLC is established and the operation strategies of the system are investigated. An operation strategy including automatic control of the opening of the electronic expansion valve based on the suction superheat of the compressor, control of the switchover period based on the relative humidity of supply air, and control of compressor frequency based on evaporation and condensation temperature is established. By using the optimal operation strategies, the dehumidification rate and COP of the system can reach 4.42 kg/h and 6.2 in summer, compared with the unoptimized strategy it increased 8% and 25%, respectively. The two performance indices can reach to 3.04 kg/h and 6.98, with an increase of 89% and 78%.

Concept and ventilation performance demonstration of graded ventilation

Advanced air distribution is essential for the energy-efficient provision of thermal comfort and indoor air quality. This study proposes a novel advanced air distribution, i.e., graded ventilation. The airflow pattern of graded ventilation is characterized by a bimodal distribution of vertical air velocity and a unimodal distribution of vertical air temperature. Graded ventilation possesses four mechanisms for high energy-efficient provision of thermal comfort and indoor air quality. First, graded ventilation has a high conditioned air supply efficiency into the occupied zone, particularly the head level, for both thermal comfort and indoor air quality, due to the push-down and pull-down forces of the internal airflow recycling. Second, graded ventilation decouples outdoor fresh air and return air, with high outdoor fresh air supply efficiency for indoor air quality. Third, graded ventilation utilizes higher-quality conditioned air for the zone, which is more critical to thermal comfort and indoor air quality. Fourth, graded ventilation only handles the cooling load of the outdoor fresh air without handling the cooling load of the return air. Case studies demonstrate that compared with mixing ventilation, Type-I stratum ventilation, Type-II stratum ventilation, and interactive cascade ventilation, graded ventilation improves energy efficiency by 49.7%–55.4%, 24.8%–29.1%, 16.3%–23.3%, and 8.4%–12.3% respectively for thermal comfort and indoor air quality. Therefore, this study advances air distribution for low-carbon, thermally comfortable, and healthy buildings.

Analysis of in-vehicle air quality and load factor as environmental and social dimensions of sustainable urban mobility: A case study from Kathmandu valley, Nepal

Introduction: Assessing in-vehicle air pollution and load factor is crucial in developing countries like Nepal within the environmental and social aspects of sustainable urban mobility. Materials and methods: In this study in-vehicle air quality of public vehicles in Kathmandu valley was monitored for three road sections based on vehicle density i.e. Ring Road Section (RRS), Urban Commercial Route 1 (UCR1), and Urban Commercial Route 2 (UCR2) using Air Visual Pro N1 Model for which validationand was done with reference Particulate Matter (PM) values obtained from the GRIMM EDM 180 analyzer. The quantitative count method was used to sample passenger load. Particulate Matter (PM1, PM2.5, PM10) were monitored along with indoor-outdoor ratio for PM2.5 to know therelationship between indoor and outdoor air quality Results: A higher positive correlation between PM 2.5 and PM10 showed common sources of pollution such as road dust, and vehicle exhaust and a ratio study between them showed the dominance of coarser particles in both ambient and in-vehicle environments. RRS recorded the highest PM10 and PM2.5 exposure, possibly due to the inadequate road conditions from Kalanki to Gongabu and loose sediment deposition from roadside activities. A significant difference is observed for peak and non-peak hours due to the difference in mobility of vehicles on two different hours. Higher load factors on UCR1 and UCR2 showed the higher transportation demand on urban commercial sections for both weekdays and weekends in comparison to RRS. Conclusion: Both in-vehicle air quality and load factor for sections under study were not satisfactory and cannot be counted under sustainable urban mobility practices.