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Anthropogenic emissions from city clusters can significantly enhance secondary organic aerosol (SOA) formation in the downwind regions, while the mechanism is poorly understood. To investigate the effect of pollutants within urban plumes on organic aerosol (OA) evolution, a field campaign was conducted at a downwind site of the Pearl River Delta region of China in the fall of 2019. A time-of-flight chemical ionization mass spectrometer coupled with the Filter Inlet for Gases and Aerosols (FIGAERO–CIMS) was used to probe the gas- and particle-phase molecular composition and thermograms of organic compounds. For air masses influenced by urban pollution, strong daytime SOA formation through gas–particle partitioning was observed, resulting in higher OA volatility. The obvious SOA enhancement was mainly attributed to the gas–particle partitioning of high-volatility (semi-volatile organic compounds + intermediate volatility organic compounds + volatile organic compounds, C∗>0.3 µg m−3) organic vapors. Using the equilibrium equation could underestimate the contribution of high-volatility organic vapors, since the volatility of these species in the particle phase was lower than that in the gas phase. We speculated that the elevated NOx concentration could suppress the formation of highly oxidized products, resulting in a smooth increase of low-volatility (extremely low volatility organic compounds + low volatility organic compounds, C∗≤0.3 µg m−3) organic vapors. Evidence has shown that urban pollutants (NOx and VOCs) could enhance the oxidizing capacity, while the elevated VOCs were mainly responsible for promoting daytime SOA formation by increasing the RO2 production rate. Our results highlight the important role of urban anthropogenic pollutants in SOA control in the suburban region.

Carbonaceous aerosols constitute a crucial component of atmospheric marine aerosols among which black carbon (BC) and brown carbon (BrC) are important contributors to light absorption and hence the positive climatic radiative forcing in the marine atmosphere. We conducted month-long (5 May–9 June 2021) onboard sample collections and online measurements of carbonaceous aerosols to characterize their morphological and optical properties during a ship cruise in the South China Sea (SCS), covering a marine region of 11.9–24.5° N, 111.1–118.2° E. Single particles were collected by a single-particle sampler, and offline analyses were performed using a transmission electron microscope (TEM) coupled with energy-dispersive X-ray spectroscopy (EDS). Online measurements of BC in PM2.5 were made by a seven-wavelength aethalometer, and organic carbon (OC) and elemental carbon (EC) mass concentrations were measured by a semi-online OC/EC analyzer. Feret diameters of the single particles during navigation and stop showed size distributions with the lognormal fitting peaks at 307 and 325 nm, respectively. The fresh (without coating) and aged BC particles (after removal of coating by the electron beams in the TEM) showed same median fractal dimensions (1.61), in contrast to their different median lacunarities (0.53 vs. 0.59). The aged BC particles showed narrower Feret diameters (229–2557 nm) during navigation than those (78–2926 nm) of freshly emitted BC from the ship's own exhaust during stop. Moreover, tar balls, as one important component of single particles from ship emissions and as the tracer of biomass burning, were identified with geometrical diameters of 160–420 nm in the TEM images. The EDS analyses showed those tar balls are mainly mixed with sea salt, organics, BC, and sulfate. We also found a significant fraction of aged BC in various mixing states (core–shell, embedded) with other components of the aerosol particles after long-range transport. The campaign was further divided into several periods (the before-monsoon period, BMP; transition monsoon period, TMP; after-monsoon period, AMP; and ship pollution period, SPP) according to the wind direction during monsoon and the ship's own pollution. The median absorption Ångström exponent (AAE) values derived from all wavelengths were 1.14, 1.02, 1.08, and 1.06 for BMP, TMP, AMP, and SPP, respectively. Particularly, a median AAE value of 1.93 was obtained during two significant biomass burning events. These results showed that biomass burning (BB) and fossil fuel (FF) combustion contributed to 18 %–22 % and 78 %–82 % of all the BC light absorption without the two intense biomass burning events, during which BB and FF accounted for 42 % and 58 %, respectively. The two BB events originated from the Philippines and Southeast Asia before and after the summer monsoon. Our results demonstrated that BC can serve as the core of aged particles, but the fractal dimensions of BC aggregates were subject to little variation; moreover, such BC particles become much more aggregated after aging in the marine atmosphere, which further affects the light absorption of the BC particles in the SCS.

Organic aerosol (OA) has a significant contribution to cloud formation and hence climate change. However, high uncertainties still exist in its impact on global climate, owing to the varying physical properties affected by the complex formation and aging processes. In this study, the hygroscopicity, volatility, cloud condensation nuclei (CCN) activity, and chemical composition of particles were measured using a series of online instruments at a rural site in the Pearl River Delta (PRD) region of China in fall 2019. During the campaign, the average hygroscopicity of OA (κOA) increased from 0.058 at 30 nm to 0.09 at 200 nm, suggesting a higher oxidation state of OA at larger particle sizes, supported by a higher fraction of extremely low volatility OA (ELVOA) for larger size particles. Significantly different diurnal patterns of κOA were observed between Aitken mode particles and accumulation mode particles. For Aitken mode particles (30–100 nm), the κOA values showed daily minima (0.02–0.07) during daytime, while the accumulation mode exhibited a daytime peak (∼ 0.09). Coincidently, a daytime peak was observed for both aged biomass burning organic aerosol (aBBOA) and less oxygenated organic aerosol (LOOA) based on source apportionment, which was attributed to the aging processes and gas–particle partitioning through photochemical reactions. In addition, the fraction of semi-volatile OA (SVOA) was higher at all measured sizes during daytime than during nighttime. These results indicate that the formation of secondary OA (SOA) through gas–particle partitioning can generally occur at all diameters, while the aging processes of pre-existing particles are more dominated in the accumulation mode. Furthermore, we found that applying a fixed κOA value (0.1) could lead to an overestimation of the CCN number concentration (NCCN) up to 12 %–19 % at 0.1 %–0.7 % supersaturation (SS), which was more obvious at higher SS during daytime. Better prediction of NCCN could be achieved by using size-resolved diurnal κOA, which indicates that the size dependence and diurnal variations in κOA can strongly affect the NCCN at different SS values. Our results highlight the need for accurately evaluating the atmospheric evolution of OA at different size ranges and their impact on the physicochemical properties and hence climate effects.

The contribution of new particle formation (NPF) to cloud condensation nuclei (CCN) number concentration (NCCN) varies largely under different environments and depends on several key factors such as formation rate (J), growth rate (GR), distribution of preexisting particles, and properties of new particles during NPF events. This study investigates the contribution of NPF to the NCCN and its controlling factors based on measurements conducted at the Heshan supersite, in the Pearl River Delta (PRD) region of China during fall 2019. The size-resolved cloud condensation nuclei activity and size-resolved particle hygroscopicity were measured by a cloud condensation nuclei counter (CCNc) and a hygroscopic tandem differential mobility analyzer (HTDMA), respectively, along with a scanning mobility particle sizer (SMPS) and a diethylene glycol scanning mobility particle sizer (DEG-SMPS) for particle number size distribution (PNSD). A typical NPF event on 29 October was chosen to investigate the contribution of the NPF to NCCN under several supersaturation (SS) ratios. Two particle properties (hygroscopicity and surface tension) affect CCN activation with the latter being more important in terms of the CCN concentration (NCCN). A lower value of surface tension (i.e., 0.06 N m−1) than the pure-water assumption (0.073 N m−1) could increase the NCCN at SS = 1.0 % by about 20 % during the nonevent period and by about 40 % during the event. In addition, an earlier peak time corresponding to a lower critical diameter (D50) was also observed. The results show that high formation rate, growth rate, and low background particle concentration lead to high number concentrations of newly formed particles. The high growth rate was found to have the most significant impact on the NCCN, which can be attributed to the fact that a higher growth rate can grow particles to the CCN size in a shorter time before they are scavenged by preexisting particles. Two other NPF events (an event on 18 October in this campaign and an event on 12 December 2014 in Panyu) were chosen to perform sensitivity tests under different scenarios (growth rate, formation rate, and background particle concentration). The calculated NCCN at SS = 1.0 % on 12 December 2014 was significantly lower than that from the other two events. The event on 12 December was re-simulated using the growth rate taken from the event on 18 October which resulted in similar CCN concentrations between the two events (12 December and 18 October), implying that the growth rate is the major impact factor for CCN activation. Our results highlight the importance of growth rate and surface tension when evaluating the contribution of NPF to the NCCN.

Aerosol particles in marine atmosphere have been shown to significantly affect cloud formation, atmospheric optical properties, and climate change. However, high temporally and spatially resolved atmospheric measurements over the sea are currently sparse, limiting our understanding of aerosol properties in marine atmosphere. In this study, a ship-based cruise campaign was conducted over the northern South China Sea (SCS) region during summertime 2018. The chemical composition of non-refractory PM1 (NR-PM1), the particle number size distribution (PNSD), and size-resolved cloud condensation nuclei (CCN) activity were measured by a time-of-flight aerosol chemical speciation monitor (ToF-ACSM) and the combination of a cloud condensation nuclei counter (CCNc) and a scanning mobility particle sizer (SMPS). Overall, aerosol particles exhibited a unimodal distribution centering at 60–80 nm and the chemical composition of the NR-PM1 was dominated by sulfate (∼ 46 %), which likely originated from anthropogenic emissions rather than dimethyl sulfide (DMS) oxidation. Two polluted episodes (P1 and P2) were observed, and both were characterized by high particle number concentrations (NCN) which originated from local emissions and from emissions in inland China via long-range transport. The concentrations of trace gases (i.e., O3, CO, NOx) and particles (NCN and NCCN at ss = 0.34 %) were elevated during P2 at the end of the campaign and decreased with offshore distance, further suggesting important impacts of anthropogenic emissions from the inland Pearl River Delta (PRD) region. Two relatively clean periods (C1 and C2) prior to and after tropical storm Bebinca were classified and the air was affected by air masses from the southwest and from the Indo-Chinese Peninsula, respectively. Chemical composition measurements showed an increase in organic mass fraction during P2 compared to C2; however, no obviously different κ values were obtained from the CCNc measurements, implying that the air masses carried pollutants from local sources during long-range transport. We report an average value of about 0.4 for the aerosol hygroscopicity parameter κ, which falls within the literature values (i.e., 0.2–1.0) for urban and remote marine atmosphere. In addition, our results showed that the CCN fraction (NCCN∕NCN, tot) and the κ values had no clear correlation either with the offshore distance or with concentrations of the particles. Our study highlights dynamical variations in particle properties and the impact of long-range transport from continental China and the Indo-Chinese Peninsula on the northern SCS region during summertime.

Turner syndrome (TS) is a gonadal dysgenesis caused by absence or structural abnormalities of sex chromosome. Isochromosome Mosaic TS is a structurally abnormal X chromosome consisting of either two short or two long arms, with only an 8-9% prevalence among women with TS based on international studies. The present report describes a 30-year-old female with isochromosome mosaic karyotype TS. The patient had no menarche so far. G-banding chromosome analysis indicated mosaic 45, X[3]/46, X, i(X) (q10)[79]/47, X, i(X)(q10), i(X)(q10), i(X)(q10)[3]/49, X, i(X)(q10), i(X)(q10), i(X)(q10), i(X)(q10)[79]. Both clinical and cytogenetic investigations proved this patient to be a special isochromosome Xq Mosaic TS with autoimmune hypothyroidism and hyperlipidemia.

Microorganisms in petroleum reservoirs play significant roles in hydrocarbon degradation, and through the terminal electron-accepting process of methanogenesis, they also contribute to microbially enhanced oil recovery (MEOR) worldwide, with great economic and environmental benefits. Here, a molecular investigation, using the 16S rRNA and mcrA gene profiles based on MiSeq sequencing and clone library construction methods, was conducted on oil and water (aqueous) phases of samples of high (82–88 ∘C), moderate (45–63 ∘C), and low temperatures (21–32 ∘C) from seven petroleum reservoirs in China. A core bacterial microbiome with a small proportion of shared operational taxonomic unit (OTU) values, but a high proportion of sequences among all reservoirs was discovered, including aerobic degraders, sulfate- and nitrate-reducing bacteria, fermentative bacteria, and sulfur-oxidizing bacteria distributed mainly in Proteobacteria, Bacteroidetes, Deferribacteres, Deinococcus–Thermus, Firmicutes, Spirochaetes, and Thermotogae. Their prevalence in the previously reported petroleum reservoirs and successive enrichment cultures suggests their common roles and functions involved in aliphatic and aromatic hydrocarbon degradation. The methanogenic process generally shifts from the dominant hydrogenotrophic pathway in the aqueous phase to the acetoclastic pathway in the oil phase in high-temperature reservoirs, but the opposite was true for low-temperature reservoirs. No difference was detected between the two phases in moderate temperature reservoirs. Physicochemical factors, including pH; temperature; phase conditions; and nitrate, Mn2+, and Mg2+ concentrations were the main factors correlated to the microbial compositional and functional profiles significantly. Linear discriminant analysis (LDA) effect size (LEfSe) analysis shows distribution differences of microbial groups towards pH, temperature, and the oil and aqueous phases. Using the software Tax4Fun for functional profiling indicated functional metabolism differences between the two phases, including amino acids, hydrocarbons in the oil phase, and carbohydrates in the aqueous phase.

Extreme significant wave heights are assessed in the South China Sea (SCS), as assessments of wave heights are crucial for coastal and offshore engineering. Two significant factors include the initial database and assessment method. The initial database is a basis for assessment, and the assessment method is used to extrapolate appropriate return-significant wave heights during a given period. In this study, a 40-year (1975–2014) hindcast of tropical cyclone waves is used to analyse the extreme significant wave height, employing the peak over threshold (POT) method with the generalized Pareto distribution (GPD) model. The peak exceedances over a sufficiently large value (i.e. threshold) are fitted; thus, the return-significant wave heights are highly dependent on the threshold. To determine a suitable threshold, the sensitivity of return-significant wave heights and the characteristics of tropical cyclone waves are studied. The sample distribution presents a separation that distinguishes the high sample from the low sample, and this separation is within the stable threshold range. Because the variation in return-significant wave heights in this range is generally small and the separation is objectively determined by the track and intensity of the tropical cyclone, the separation is selected as a suitable threshold for extracting the extreme sample in the tropical cyclone wave. The asymptotic tail approximation and estimation uncertainty show that the selection is reasonable.

Many high and steep slopes are comprised of special topographic and geomorphic types and formed through mining activities during the construction of mountain expressways. Severe soil erosion may also occur under heavy rainfall conditions. Therefore, predicting soil loss on highway slopes is important in protecting infrastructure and human life. In this study, we investigate Xinhe Expressway located at the southern edge of the Yunnan–Guizhou Plateau. The Revised Universal Soil Loss Equation (RUSLE) is used as the prediction model for soil and water loss on slopes. Geographic information systems, remote sensing technology, field surveys, run-off plot observation testing, cluster analysis and co-kriging calculations are also utilised. The partition of the prediction units of soil loss on the expressway slope in the mountainous area and the spatial distribution of rainfall on a linear highway are studied. Given the particularity of the expressway slope in the mountainous area, the model parameter is modified, and the risk of soil loss along the mountain expressway is simulated and predicted under 20- and 1-year rainfall return periods. The following results are obtained. (1) Natural watersheds can be considered for the prediction of slope soil erosion to represent the actual situation of soil loss on each slope. Then, the spatial location of the soil erosion unit can be determined. (2) Analysis of actual observation data shows that the overall average absolute error of the monitoring area is 0.39 t ha−1, the overall average relative error is 33.96 % and the overall root mean square error is between 0.21 and 0.66, all of which are within acceptable limits. The Nash efficiency coefficient is 0.67, indicating that the prediction accuracy of the model satisfies the requirements. (3) Under the 1-year rainfall return period condition, we find through risk classification that the percentage of prediction units with no risk of erosion is 78 %. The soil erosion risk is low and does not affect road traffic safety. Under the 20-year return period rainfall condition, the percentage of units with high and extremely high risks is 7.11 %. The prediction results can help adjust the design of water and soil conservation measures for these units.

Abstract Background Checkpoint blockade immunotherapy has improved metastatic cancer patient survival, but response rates remain low. There is an unmet need to identify mechanisms and tools to circumvent resistance. In human patients, responses to checkpoint blockade therapy correlate with tumor mutation load, and intrinsic resistance associates with pre-treatment signatures of epithelial mesenchymal transition (EMT), immunosuppression, macrophage chemotaxis and TGFβ signaling. Methods To facilitate studies on mechanisms of squamous cell carcinoma (SCC) evasion of checkpoint blockade immunotherapy, we sought to develop a novel panel of murine syngeneic SCC lines reflecting the heterogeneity of human cancer and its responses to immunotherapy. We characterized six Kras-driven cutaneous SCC lines with a range of mutation loads. Following implantation into syngeneic FVB mice, we examined multiple tumor responses to α-PD-1, α-TGFβ or combinatorial therapy, including tumor growth rate and regression, tumor immune cell composition, acquired tumor immunity, and the role of cytotoxic T cells and Tregs in immunotherapy responses. Results We show that α-PD-1 therapy is ineffective in establishing complete regression (CR) of tumors in all six SCC lines, but causes partial tumor growth inhibition of two lines with the highest mutations loads, CCK168 and CCK169. α-TGFβ monotherapy results in 20% CR and 10% CR of established CCK168 and CCK169 tumors respectively, together with acquisition of long-term anti-tumor immunity. α-PD-1 synergizes with α-TGFβ, increasing CR rates to 60% (CCK168) and 20% (CCK169). α-PD-1 therapy enhances CD4 + Treg/CD4 + Th ratios and increases tumor cell pSmad3 expression in CCK168 SCCs, whereas α-TGFβ antibody administration attenuates these effects. We show that α-TGFβ acts in part through suppressing immunosuppressive Tregs induced by α-PD-1, that limit the anti-tumor activity of α-PD-1 monotherapy. Additionally, in vitro and in vivo, α-TGFβ acts directly on the tumor cell to attenuate EMT, to activate a program of gene expression that stimulates immuno-surveillance, including up regulation of genes encoding the tumor cell antigen presentation machinery. Conclusions We show that α-PD-1 not only initiates a tumor rejection program, but can induce a competing TGFβ-driven immuno-suppressive program. We identify new opportunities for α-PD-1/α-TGFβ combinatorial treatment of SCCs especially those with a high mutation load, high CD4+ T cell content and pSmad3 signaling. Our data form the basis for clinical trial of α-TGFβ/α-PD-1 combination therapy (NCT02947165).

As functionally graded material (FGM) plates are widely used in engineering and industrial fields, the fracture strength evaluation of the cracked FGM plate becomes increasingly important. However, due to the gradation of the mechanical properties of FGM, few analytical methods are simple and available. In this paper, a convenient strength evaluation method for the cracked FGM plates under different loadings is proposed in terms of the stress intensity factor (SIF) appearing at a crack tip. This method uses the stable relationship of singular stress fields between FGM and homogeneous material to greatly simplify the complex SIF calculation process of the cracked FGM plate. The results show that the SIFs of FGM plates under tension, bending, and three-point bending (experiment) can be obtained conveniently and accurately by using two simple formulas, and the trends of critical SIF can also be investigated directly even if the SIF solution of the homogeneous plate (reference problem) is unknown. Comparisons with the published theoretical and experimental results indicated that the present method is reliable, precise, and practical to determine SIF and perform strength prediction.

Ever-increasing demands for a higher bandwidth of data in the optical communications augment the operating frequency of components and systems. To accelerate the development of these large-bandwidth technologies, there is a growing demand to characterize the frequency response of optical devices in real time. In this work, we report a method to significantly improve the measurement speed of an optical vector network analyzer (OVNA) with coherent time-stretch (CTS). Single-shot frequency spectrum measurements are enabled by time-stretch technology that maps the spectrum of an optical pulse to the time domain. Compared to single-ended detection, the implementation of coherent detection enables the acquiring of accurate phase information of the signal and also provides the digital processed cancellation of dispersion-induced impairments. By utilizing dispersive time-stretch and digital coherent detection techniques, we demonstrate an ultrafast and wide bandwidth OVNA. We successfully characterize its performance by measuring the frequency response of a micro-ring cavity and a silicon Mach–Zehnder interferometer with 0.07-nm spectral resolution and 0.156-rad phase accuracy over 10-nm bandwidth. Meanwhile, the dynamic responses of the magnitude and phase, and the drift of the resonance wavelength of the micro-ring modulator under thermal tuning, were fully recorded by the CTS-OVNA at a 20-MHz frame rate.

This study mainly utilized the Soil and Water Assessment Tool (SWAT) together with SWAT-CUP, both free and open source software (FOSS), to construct a distributed hydrologic flow model for the Rokel-Seli River basin, Sierra Leone, in a bid to spatiotemporally evaluate the role of changes in land use/land cover (LULC) and microclimate on streamflow regimes. The model was informed by LULC data derived from three Landsat satellite images collected in 2002, 2010, and 2016. The LULC data was generated with the aid of several python libraries accessed through the FOSS Anaconda Navigator. LULC change analysis demonstrated that between 2002 and 2016, urban, agricultural, water, and mining lands expanded significantly but forest cover reduced the most (−5.7 %). While average annual surface runoff dramatically increased from 2002 to 2010 (31.7 %), the period after the reservoir construction (2010–2016) recorded lower increase in surface runoff (0.9 %). Result of the study suggested that the construction of a major reservoir to support hydroelectricity in concert with significant loss of forest cover and shrub played a greater role in increasing surface runoff compared with the influence of microclimate.

An approach for nanoscale 3-D tomography of organic carbon (OC) and associated mineral nanoparticles was developed to illustrate their spatial distribution and boundary interplay, using synchrotron-based transmission X-ray microscopy (TXM). The proposed 3-D tomography technique was first applied to in situ observation of a laboratory-made consortium of black carbon (BC) and nanomineral (TiO2, 15 nm), and its performance was evaluated using dual-scan (absorption contrast and phase contrast) modes. This novel tool was then successfully applied to a natural OC–mineral consortium from mountain soil at a spatial resolution of 60 nm, showing the fine structure and boundary of OC, the distribution of abundant nano-sized minerals, and the 3-D organo-mineral association in situ. The stabilization of 3500-year-old natural OC was mainly attributed to the physical protection of nano-sized iron (Fe)-containing minerals (Fe oxyhydroxides including ferrihydrite, goethite, and lepidocrocite), and the strong organo-mineral complexation. In situ evidence revealed an abundance of mineral nanoparticles, in dense thin layers or nano-aggregates/clusters, instead of crystalline clay-sized minerals on or near OC surfaces. The key working minerals for C stabilization were reactive short-range-order (SRO) mineral nanoparticles and poorly crystalline submicron-sized clay minerals. Spectroscopic analyses demonstrated that the studied OC was not merely in crisscross co-localization with reactive SRO minerals; there could be a significant degree of binding between OC and the minerals. The ubiquity and abundance of mineral nanoparticles on the OC surface, and their heterogeneity in the natural environment may have been severely underestimated by traditional research approaches. Our in situ description of organo-mineral interplay at the nanoscale provides direct evidence to substantiate the importance of mineral physical protection for the long-term stabilization of OC. This high-resolution 3-D tomography approach is a promising tool for generating new insight into the interior 3-D structure of micro-aggregates, the in situ interplay between OC and minerals, and the fate of mineral nanoparticles (including heavy metals) in natural environments.

Damage to the surface of railway wheels and rails commonly occurs in most railways and, if not detected at an early stage, can result in rapid deterioration and possible failure incurring high maintenance costs. If detected at an early stage these maintenance costs can be minimised. This paper presents an investigation into the use of time-frequency analysis of vibrations in railway vehicles for early detection of wheel flats and rail surface defects. Time-frequency analysis is a useful tool for identifying the content of a signal in the frequency domain without losing information about its time domain characteristics. Three commonly used time-frequency analysis techniques: Short-Time-Fourier-Transform (STFT); Wigner-Ville Transform (WVT); and Wavelet Transform (WT) are investigated in this work.

This paper deals with fault diagnosis of induction motor containing common faults by using a novel intelligent framework and transient stator current signals. This framework consists of a Fourier-Bessel (FB) expansion for analyzing the transient signals, a generalized discriminant analysis (GDA) for feature reduction, and a relevance vector machine (RVM) for fault classification. The start-up transient current signals are acquired from different motor operating conditions and decomposed into single components using FB expansion. Subsequently, a number of statistical features in the time domain and the frequency domain are computed for each component to represent the motor conditions. The high dimensionality of the feature set is reduced by implementing GDA. Finally, the diagnosis performance is carried out by RVM, which is an intelligent method in pattern recognition area. The framework has been applied for traction motor faults including bowed rotor, broken rotor bar, eccentricity, faulty bearing, mass unbalance, and phase unbalance in general applications. The results show that the proposed diagnosis framework is capable of improving the classification accuracy significantly in comparison other methods.

Railway vehicles with conventional wheelsets often experience problems of lateral instabilities or severe wear when running at high speed. The use of an independently rotating wheelset (IRW) can potentially eliminate the cause of wheelset hunting and reduce wheel wear as the mechanical feedback mechanism causing the problem is decoupled. This paper presents an investigation into the design of a novel induction motor configuration and controller for IRW in order to provide the stability required to satisfy the performance requirements for railway vehicles. A computer model of the mechanical and electrical parts of the system was developed. Simulation and experiments of the wheelsets with active driving motor control have demonstrated that a wheelset with independently driven wheels has a good stability performance over a traditional wheelset. Controllers with indirect field orientation control for dynamic control of an induction motor have shown to be suitable for this application in both its response and its controllability.