• Advanced engine flows and combustion

      Peng, Zhijun; Megaritis, Thanos; Sung, Chih-Jen; Yaga, Minoru; Hellier, Paul; Tian, Guohong; University of Bedfordshire; Brunel University; University of Connecticut; University of the Ryukyus; et al. (Hindawi, 2017-08-07)
      The transport sector accounts for a significant part of carbon emissions worldwide, and so the need to mitigate the greenhouse effect of CO2 from fossil fuel combustion, and to reduce vehicle exhaust emissions has been the primary driver for developing cleaner and more efficient vehicle powertrains, and environmentally friendly fuels.  As alternatives to combustion engines have yet to overcome technical challenges to attain significant utilisation in the transport sector, piston-driven internal combustion engines and gas turbine aero-engines remain very attractive powertrain options due to their high thermal efficiency. Meanwhile, since the introduction of various emissions standards, that have forced the employment of various aftertreatment systems, the evolution of combustion process has been significant. Advanced combustion strategies have attempted to find in-chamber approaches to either meet these emission standards fully and thus avoid the need to use aftertreatment, or at the very least, to lower the performance demands required from aftertreatment systems and thus reducing their cost and complexity. While the main focus of combustion system development has been recently to lower emissions of CO2, there is also significant interest to lower nitric oxides (NOx) and particulate matter (PM) emissions and other harmful emissions.
    • Advances in body-centric wireless communication: applications and state-of-the-art

      Abbasi, Qammer Hussain; Ur-Rehman, Masood; Alomainy, Akram; Qaraqe, Khalid (The IET, 2016-06-01)
    • Analysis of sub-channel correlation in dual-polarised MIMO systems via a polarisation diversity scheme

      Fang, Cheng; Liu, Enjie; Ur-Rehman, Masood; University of Bedfordshire (IEEE, 2017-02-23)
      A polarisation diversity combing scheme for dual-polarised multiple-input and multiple-output channels in small cell environments introduced and evaluated. The scheme is based on post analysis of channel measurement data captured from scenarios and includes indoor-to-indoor, indoor-to-outdoor, and indoor-outdoor-indoor propagation. An analysis of link signal strength and correlation with respect to frequency and polarisation revealed profound differences between copolarised and cross-polarised links in terms of received signal strength and correlation between frequencies. Utilizing these differences, a polarisation diversity combing scheme is evaluated which is shown to produce an average of 10.6-dB polarisation diversity gain.
    • Analysis of the mechanical properties of chromosomes in air and liquid by AFM

      Wang, Bowei; Yang, Fan; Dong, Jianjun; Li, Jiani; Wang, Ying; Qu, Kaige; Wei, Huimiao; Wang, Zuobin; Changchun University of Science and Technology; Changli Nano Biotechnology Ltd; et al. (IEEE, 2021-11-18)
      Chromosomes contain all the genomic information thus making the study of chromosomes practical and significant. Herein, the morphologies of chromosomes prepared with different methods were monitored by atomic force microscopy (AFM). Moreover, the mechanical properties of chromosomes in air and liquid were investigated quantitatively through AFM-based force spectroscopy. The differences of chromosome morphologies and mechanical properties caused by sample preparations indicated that the chromosome characterization in liquid was more meaningful to reveal the physiological characteristics of chromosomes.
    • Antennas for global navigation satellite systems

      Chen, Xiaodong; Parini, Clive G.; Collins, Brian; Yao, Yuan; Ur-Rehman, Masood (Wiley, 2012-03-01)
    • Antireflection silicon structures with hydrophobic property fabricated by three-beam laser interference

      Zhao, Le; Wang, Zuobin; Zhang, J.; Cao, L.; Li, L.; Yue, Y.; Li, Dayou; Changchun University of Science and Technology; University of Bedfordshire; Jiaotong-Liverpool University (Elsevier, 2015-08-15)
      This paper demonstrates antireflective structures on silicon wafer surfaces with hydrophobic property fabricated by three-beam laser interference. In this work, a three-beam laser interference system was set up to generate periodic micro-nano hole structures with hexagonal distributions. Compared with the existing technologies, the array of hexagonally-distributed hole structures fabricated by three-beam laser interference reveals a design guideline to achieve considerably low solar-weighted reflectance (SWR) in the wavelength range of 300-780 nm. The resulting periodic hexagonally-distributed hole structures have shown extremely low SWR (1.86%) and relatively large contact angle (140°) providing with a self-cleaning capability on the solar cell surface.
    • Application of water quality index for pollution detection at Luton Hoo lake

      Anyachebelu, Tochukwu Kene; Conrad, Marc; Rawson, David M.; Ajmal, Tahmina; University of Bedfordshire (IEEE, 2016-01-07)
      This study investigated contamination problems through physical and chemical surface water monitoring. The physical parameters were temperature, conductivity and turbidity while the chemical parameters were dissolved oxygen, pH and ammonium. These parameters were measured at two locations on the lake to monitor the water quality and possible sources of contamination. We evaluated the relationship of the measured parameters to contamination sources and its effect on the water quality. The collected data from the installed multi parameter sensors were analyzed to assess the difference in values at the different sensor locations based on a water quality index.
    • Asymmetric transport of light in linearly arrayed metallic nano-particles

      Aroua, Walid; Horchani, R.; AbdelMalek, Fathi; Haxha, Shyqyri; Kamli, Ali A.; National Institute of Applied Science and Technology, Tunisia; Dhofar University; University of Bedfordshire; Jazan University, Saudi Arabia (Springer, 2016-09-15)
      A strong asymmetric light transport in a linear chain of spherical and equidistantly spaced silver metal nano-particles (MNPs) located near a substrate is reported. The contrast ratio of the proposed structure is above 0.95. We have studied the propagation of light in the array with respect to the metal and the size of the last nano-particle of the chain and the nature of the substrate. It is shown also that the presence of a copper or gold substrate enhance the guiding properties of the array. This structure opens the possibility to design various optical devices such as broadband antennae and optical diodes.
    • Authentication in millimeter-wave body-centric networks through wireless channel characterization

      Zhao, Nan; Zhang, Zhiya; Ur-Rehman, Masood; Ren, Aifeng; Yang, Xiaodong; Zhao, Jianxun; Zhao, Wei; Dong, Binbin; Xidian University; University of Bedfordshire (IEEE, 2017-11-13)
      Advent of 5G technologies has ensued in massive growth of body-centric communications (BCC), especially at millimeter-wave frequencies. As a result, the portable/handheld terminals are becoming more and more “intelligent” but not without the cost of being less secure. Improved authentication measures need to be explored, as effective identity authentication is the first level of security in these devices. This paper presents a novel keyless authentication method exploiting wireless channel characteristics. Human palm has distinct transmission coefficient (S21) for each of the users and is used for in-vivo fingerprint identification in this work. A detailed channel modeling using data acquisition from real environment and empirical approach is adopted to evaluate the usability of this method. The results show that this method can provide a secure operation for the millimeter-wave 5G BCCs.
    • Automated ontology framework for service robots

      Kanjaruek, Saranya; Li, Dayou; Qiu, Renxi; Boonsim, Noppakun; University of Bedfordshire (Institute of Electrical and Electronics Engineers Inc., 2016-02-25)
      This paper presents an automated ontology framework for service robots. The framework is designed to automatically create an ontology and an instance of concept in dynamic environment. Ontology learning from text is applied to build a concept hierarchy using WordNet which provides a rich semantic processing for physical objects. The Automated Ontology is composed of four modules: Concept Creation, Property Creation, Relationship Creation and Instance of Concept Creation. The automated ontology algorithm was implemented in order to create the concept hierarchy in the Robot Ontology. The Semantic Knowledge Acquisition represents knowledge of physical objects in dynamic environments. In simulation experiments, the list of object names and property names was identified. The result shows the concept hierarchy which represents explicit terms and the semantic knowledge of physical objects for performing everyday manipulation tasks.
    • Baseline and triangulation geometry in a standard plenoptic camera

      Hahne, Christopher; Aggoun, Amar; Velisavljević, Vladan; Fiebig, Susanne; Pesch, Matthias (Springer, 2017-09-22)
      In this paper, we demonstrate light field triangulation to determine depth distances and baselines in a plenoptic camera. The advancement of micro lenses and image sensors enabled plenoptic cameras to capture a scene from different viewpoints with sufficient spatial resolution. While object distances can be inferred from disparities in a stereo viewpoint pair using triangulation, this concept remains ambiguous when applied in case of plenoptic cameras. We present a geometrical light field model allowing the triangulation to be applied to a plenoptic camera in order to predict object distances or to specify baselines as desired. It is shown that distance estimates from our novel method match those of real objects placed in front of the camera. Additional benchmark tests with an optical design software further validate the model’s accuracy with deviations of less than 0:33 % for several main lens types and focus settings. A variety of applications in the automotive and robotics field can benefit from this estimation model.
    • Broadband antennas

      Zhang, Zhiya; Ur-Rehman, Masood; Yang, Xiaodong; Serpedin, Erchin; Ren, Aifeng; Zuo, Shaoli; Rahman, Atiqur; Abbasi, Qammer Hussain (IGI Global, 2015-08-01)
    • Capture and sorting of multiple cells by polarization-controlled three-beam interference

      Hou, Yu; Wang, Zuobin; Hu, Yaowei; Li, Dayou; Qiu, Renxi; Changchun University of Science and Technology; University of Bedfordshire (IOP PUBLISHING LTD, 2016-02-02)
      For the capture and sorting of multiple cells, a sensitive and highly efficient polarization-controlled three-beam interference set-up has been developed. With the theory of superposition of three beams, simulations on the influence of polarization angle upon the intensity distribution and the laser gradient force change with different polarization angles have been carried out. By controlling the polarization angle of the beams, various intensity distributions and different sizes of dots are obtained. We have experimentally observed multiple optical tweezers and the sorting of cells with different polarization angles, which are in accordance with the theoretical analysis. The experimental results have shown that the polarization angle affects the shapes and feature sizes of the interference patterns and the trapping force.
    • Cell spreading behaviors on hybrid nanopillar and nanohole arrays

      Wu, Xiaomin; Li, Li; Wang, Lu; Lei, Zecheng; Yang, Fan; Liu, Ri; Wang, Ying; Peng, Kuiqing; Wang, Zuobin; Wu X (IOP Publishing, 2021-11-05)
      Although nanopillars (NPs) provide a promising tool for capturing tumor cells, the effect of mixing NPs with other nanopatterns on cell behavior remains to be further studied. In this paper, a method of fabricating silicon nanoscale topographies by combining laser interference lithography with metal assisted chemical etching was introduced to investigate the behaviors and pseudopodia of A549 cells on the topologies. It was found that cells had a limited manner in spreading with small cell areas on the silicon nanopillar (SiNP) arrays, but a good manner in spreading with large cell areas on the silicon nanohole (SiNH) arrays. When on the hybrid SiNP/SiNH arrays, cells had medium cell areas and they arranged orderly along the boundaries of SiNPs and SiNHs, as well as 80% of cells displayed a preference for SiNPs over SiNHs. Furthermore, the lamellipodia and filopodia are dominant in the hybrid SiNP/SiNH and SiNP arrays, respectively, both of them are dominant in the SiNH arrays. In addition, the atomic force acoustic microscopy was also employed to detect the subsurface features of samples. The results suggest that the hybrid SiNP/SiNH arrays have a targeted trap and elongation effect on cells. The findings provide a promising method in designing hybrid nanostructures for efficient tumor cell traps, as well as regulating the cell behaviors and pseudopodia.
    • Cellular shear adhesion force measurement and simultaneous imaging by atomic force microscope

      Hou, Yu; Wang, Zuobin; Li, Dayou; Qiu, Renxi; Li, Yan; Jiang, Jinlan; Changchun University of Science and Technology; Chinses Academy of Sciences; University of Bedfordshire; Jilin University (Springer, 2017-01-06)
      This paper presents a sensitive and fast cellular shear adhesion force measurement method using an atomic force microscope (AFM). In the work, the AFM was used both as a tool for the imaging of cells on the nano-scale and as a force sensor for the measurement of the shear adhesion force between the cell and the substrate. After the cell imaging, the measurement of cellular shear adhesion forces was made based on the different positions of the cell on the nano-scale. Moreover, different pushing speeds of probe and various locations of cells were used in experiments to study their influences. In this study, the measurement of the cell adhesion in the upper portion of the cell is different from that in the lower portion. It may reveal that the cancer cells have the metastasis tendency after cultured for 16 to 20 hours, which is significant for preventing metastasis in the patients diagnosed with early cancer lesions. Furthermore, the cellular shear adhesion forces of two types of living cancer cells were obtained based on the measurements of AFM cantilever deflections in the torsional and vertical directions. The results demonstrate that the shear adhesion force of cancer cells is twice as much as the same type of cancer cells with TRAIL. The method can also provide a way for the measurement of the cellular shear adhesion force between the cell and the substrate, and for the simultaneous exploration of cells using the AFM imaging and manipulation
    • Characteristics of near-nozzle spray development from a fouled GDI injector

      Zhou, Jianwei; Pei, Yiqiang; Peng, Zhijun; Zhang, Yanfeng; Qin, Jing; Wang, Li; Liu, Changwen; Zhang, Xiaoyu; Tianjin University; University of Bedfordshire; et al. (Elsevier Ltd, 2018-03-16)
      The near-nozzle spray development of a typical fouled gasoline direct injection (GDI) injector was investigated. The fouled injector had been used in a stratified-charge combustion GDI engine and showed typical characteristics, such as accumulated deposits inside and around the nozzles and a reduced flow rate of 2.9–5.7%. Back-illumination and Mie-scattering methods were employed in spray experiments, in conjunction with a high speed camera and a macro lens, to assess the near-nozzle spray behaviors. The experimental results show that at all injection pressures tested, the interaction between deposits and spray led to several poor spray behaviors during the full injection evolution, including spray distortion, residual fuel storage in the nozzles and deposits layer, liquid splashing, the formation of ligament and large droplets and tip wetting/dripping. These effects all may result in high soot emissions. The after-injection stage of the fouled injector produced more liquid ligaments than that of the new injector. It was also found that high injection pressures did not improve atomization during after-injection, nor reduce the amounts of ligaments and droplet clusters beyond the main spray boundary. The plume width and projected spray area of a single nozzle in the fouled injector were decreased by 5–7% and 17–20%, respectively, due to fuel flow losses. The delays in the start of injection and end of injection were approximately 20 μs and 30–40 μs, respectively.
    • A closed-loop reciprocity calibration method for massive MIMO in terrestrial broadcasting systems

      Luo, Hua; Zhang, Yue; Huan, Li-Ke; Cosmas, John; Aggoun, Amar; University of Bedfordshire; Brunel University; Cobham Wireless (IEEE, 2016-09-22)
      Massive multi-input multioutput (MIMO) is believed to be an effective technique for future terrestrial broadcasting systems. Reciprocity calibration is one of the major practical challenges for massive MIMO systems operating in time-division duplexing mode. A new closed-loop reciprocity calibration method is investigated in this paper which can support online calibration with a higher accuracy compared to the existing methods. In the first part of the proposed method, an optimized relative calibration is introduced using the same structure of traditional relative calibration, but with less impaired hardware in the reference radio chain. In the second part, a test device (TD)-based calibration is proposed which makes online calibration possible. An experiment setup is built for the measurement of the base station hardware impairments and TD-based calibration implementation. Simulation results and the error vector magnitude of UE received signal after calibration show that the performance of our proposed method is improved significantly compared to the existing relative calibration methods.
    • A compact size implantable antenna for bio-medical applications

      Malik, Nabeel A.; Ajmal, Tahmina; Sant, Paul; Ur-Rehman, Masood; University of Bedfordshire; University of Glasgow (Institute of Electrical and Electronics Engineers Inc., 2020-09-29)
      Implantable antennas play a vital role in implantable sensors and medical devices. In this paper, we present the design of a compact size implantable antenna for biomedical applications. The antenna is designed to operate in ISM band at 915 MHz and the overall size of the antenna is 4 imes 4 imes 0.3 mm {3}. A shorting pin is used to lower the operating frequency of the antenna. For excitation purpose a 50-ohm coaxial probe feed is used in the design. A superstrate layer is placed on the patch to prevent the direct contact between the radiating patch and body tissues. The antenna is simulated in skin layer model. The designed antenna demonstrates a gain of 3.22 dBi while having a-10 dB bandwidth of 240 MHz with good radiation characteristics at 915 MHz. The simulated results show that this antenna is an excellent candidate for implantable applications.
    • Comparative study on the macroscopic characteristics of gasoline and ethanol spray from a GDI injector under injection pressures of 10 and 60 MPa

      Li, Xiang; Li, Dayou; Liu, Jingyin; Ajmal, Tahmina; Aitouche, Abdel; Mobasheri, Raouf; Rybdylova, Oyuna; Pei, Yiqiang; Peng, Zhijun (ACS, 2022-03-04)
      To reduce particulate matter (PM) emissions from vehicles powered by gasoline direct injection (GDI) engines, increasing the fuel injection pressure has been one promising approach. However, a comparison of macroscopic characteristics between gasoline and ethanol from a GDI injector under an ultrahigh injection pressure of more than 50 MPa has not been reported. The experimental study presented in this paper can provide some new and valuable information about comparing and analyzing the macroscopic characteristics of gasoline and ethanol spray from a GDI injector in both front and side views under injection pressures of 10 and 60 MPa. The experimental results show that compared to ethanol, gasoline spray has a slight advantage in LS (penetration of whole spray), LC (penetration of core region of spray), θS (spray cone angle), and RI (irregularity of spray boundary) under both PI (injection pressure) = 10 MPa and PI = 60 MPa, which would promote a more homogeneous mixture of air and fuel. Furthermore, the advantage of gasoline in θS is more pronounced under PI = 60 MPa. At the end of injection, SS (area of whole spray) of gasoline is around 2% larger than ethanol, while its advantage in SC (area of core region of spray) can be around 5%. With the increase of PI from 10 to 60 MPa, a marked increase of RS (the ratio of SC to SS) and RI indicates that atomization and air–fuel mixture homogeneity can be significantly improved for both gasoline and ethanol spray. Besides, a minor revision to the Dent model helps achieve a significant improvement in the prediction accuracy of LS for both gasoline and ethanol spray under injection pressures of 10 and 60 MPa.
    • Convexity characterization of virtual view reconstruction error in multi-view imaging

      Velisavljević, Vladan; Dorea, Camilo; Chakareski, Jacob; de Queiroz, Ricardo (IEEE, 2017-09-22)
      Virtual view synthesis is a key component of multi-view imaging systems that enable visual immersion environments for emerging applications, e.g., virtual reality and 360-degree video. Using a small collection of captured reference viewpoints, this technique reconstructs any view of a remote scene of interest navigated by a user, to enhance the perceived immersion experience. We carry out a convexity characterization analysis of the virtual view reconstruction error that is caused by compression of the captured multi-view content. This error is expressed as a function of the virtual viewpoint coordinate relative to the captured reference viewpoints. We derive fundamental insights about the nature of this dependency and formulate a prediction framework that is able to accurately predict the specific dependency shape, convex or concave, for given reference views, multi-view content and compression settings. We are able to integrate our analysis into a proof-of-concept coding framework and demonstrate considerable benefits over a baseline approach.