Article
Optics
H. A. Zain, M. Batumalay, H. R. A. Rahim, M. Yasin, S. W. Harun
Summary: The proposed micro-bottle resonator sensor, coated with HEC/PVDF, shows good response and sensitivity to relative humidity. The sensor element was formed using a softening and compressing technique, and the use of a 3 μm tapered microfiber for optical excitation resulted in a high-quality factor and excellent performance within a relative humidity range of 40-80%.
Article
Engineering, Electrical & Electronic
Pedro Vitor Taranto de Carvalho, Maria Aparecida Goncalves Martinez, Maria Thereza Rocco Giraldi
Summary: A high-sensitivity relative humidity optical fiber sensor based on an intermodal interference structure is proposed, with a tapered no-core fiber coated with an RH-sensitive material. Investigating various coating materials and dimensions, it is found that the sensitivity of the sensor can be tuned by adjusting the parameters.
OPTICAL AND QUANTUM ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Xuhui Zhang, Xinpu Zhang, Yang Zhang, Yun Liu, Wei Peng
Summary: The proposed optical fiber relative humidity sensor, utilizing multiwalled carbon nanotubes and graphene oxide composite as the humidity-sensitive film, demonstrates high sensitivity and excellent performance. The sensor is based on a multimode interference structure, with the long-range MWCNT-based film showing higher sensitivity and a wide linear measurement range.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2021)
Article
Engineering, Electrical & Electronic
Ning Chen, Xue Zhou, Xuegang Li
Summary: A highly sensitive humidity sensor with low-temperature sensitivity is realized by plating a PVA moisture-sensitive film onto a tapered optical fiber. The sensor shows high humidity sensitivity and low-temperature sensitivity, allowing for accurate measurement of environmental humidity while eliminating temperature interference. Additionally, the sensor exhibits excellent reversibility, stability, and advantages typical of optical fiber sensors.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2021)
Article
Optics
Jinghua Fu, Yanyan Xu, Mingjing Xu, Lashari Ghulam Abbas, Ai Zhou
Summary: This study proposes and demonstrates a highly sensitive humidity sensor based on a fiber Mach-Zehnder Interferometer (MZI). The sensor consists of a tapered dual side-hole fiber (DSHF) and a graphene oxide (GO) film coating, which improves the humidity sensitivity. The experimental results show significant enhancement in humidity sensitivity compared to sensors without the GO coating.
Article
Multidisciplinary Sciences
Nader Shehata, Remya Nair, Rabab Boualayan, Ishac Kandas, Abdulrazak Masrani, Eman Elnabawy, Nada Omran, Mohammed Gamal, Ahmed H. Hassanin
Summary: In this research, nanocomposite membranes of different blend ratios from PVDF and TPU were synthesized. It was found that TPU blending ratios of 15-17.5% gave higher output voltage and higher piezosensitivity. TPU addition can partially compensate PVDF and enhance the piezoelectric response of the nanocomposite mats.
SCIENTIFIC REPORTS
(2022)
Article
Instruments & Instrumentation
Aneez Syuhada, Muhammad Salleh Shamsudin, Suzairi Daud, Ganesan Krishnan, Sulaiman Wadi Harun, Muhammad Safwan Abd Aziz
Summary: A sensitive tapered optical fiber sensor incorporating graphene oxide and polyvinyl alcohol composite film for rapid measurement of changes in relative humidity was proposed and experimentally demonstrated. The sensor showed a good response with its signal increasing linearly with the surrounding humidity, achieving the highest sensitivity with a specific coating. The study also measured and analyzed the stability, repeatability, reversibility, and response time of the designated sensor.
Article
Engineering, Electrical & Electronic
Jiangxiao Qian, Wei Wang, Haibin Chen, Junying Zhang, Guanghai Liu, Zilong Guo, Xiongxing Zhang, Xiaohui Li
Summary: A simple in-fiber breathing monitoring sensor based on a micro-tapered long-period fiber grating structure is proposed and demonstrated. The structure is manufactured through the periodical tapering of an optical fiber utilizing a CO2 laser fusion splicer. The sensor can directly and dynamically monitor relative humidity with a fast response, and thus monitor the breathing process in real time. Experimental results show that the sensor successfully monitors breathing rate and status during respiration when placed nearby the nose in a breathing mask. The proposed sensor has advantages of simple fabrication, miniature size, and fast response, which makes it potentially useful in visual observation of patients' breathing condition.
IEEE SENSORS JOURNAL
(2023)
Article
Engineering, Electrical & Electronic
Ben Xu, Yun Guo, Xingchao Ma, Yingfang Zhang, Chun-Liu Zhao, D. N. Wang
Summary: A tip Michelson interferometer (MI) is proposed and experimentally demonstrated for relative humidity (RH) sensing. The device consists of a short capillary tube with a small inner diameter that is spliced to a single-mode fiber (SMF) and coated with agarose gel on its end face, and the solid capillary wall and gel act as the sensing arm of the MI. The relationship between the structural parameters and the performance of the device is revealed, and the maximum sensitivity of 0.752 nm/% RH with a linear correlation coefficient of 0.9927 within the range of 25%-90% RH is obtained. The proposed sensor exhibits good performances of robustness, compact size, high repeatability, fast response (<100 ms), and small measurement uncertainty (<0.21% RH), making it promising for accurate static or dynamic moisture measuring.
IEEE SENSORS JOURNAL
(2023)
Article
Chemistry, Analytical
Bartlomiej Guzowski, Mateusz Lakomski
Summary: This paper presents the fabrication and characterization of a temperature sensor based on periodically tapered optical fibers (PTOF). The study investigates the relation between the geometry of the sensors and sensing ability, emphasizing the importance of the number of tapered regions in PTOF for temperature response. Results show that sensors with a low number of tapered regions cannot be considered effective for temperature sensing, while sensors with more tapered regions demonstrate excellent sensitivity and linear fitting.
Article
Optics
Xi Yang, Zhihua Shao, Huanhuan Yin, Xueguang Qiao
Summary: This study proposes and experimentally demonstrates a compact fiber-optic ultrasonic sensor based on a tapered multi-core fiber (TMCF). Comparative analysis and measurements are performed between tapered four-core fibers and tapered seven-core fibers, revealing that multiple modes can be easily excited and coupled in the tapered region of the TMCF, resulting in highly sensitive inter-mode interference. By utilizing the evanescent field interaction between the surrounding water and transmitting light, the transmission spectrum of the TMCF is modulated periodically due to the change in water's refractive index caused by ultrasonic waves. The sensor, packaged on a polyurethane rod as an ultrasonic probe, successfully obtains high signal-to-noise voltage signals and clearly images the profile of a trapezoidal physical model using scanning detection.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Engineering, Multidisciplinary
Zefeng Li, Yuequn Zheng, Zeying Zhou, Yusheng Liang, Jialin Zhang, Guoyong Sun
Summary: This study theoretically analyzes and experimentally demonstrates the relationship between the temperature and strain sensitivities and the waist diameter of the tapered high birefringence fiber (THBF) in a Sagnac interferometer. Sagnac interference is sensitive to both temperature and strain when the waist diameter is large, but the sensitivities decrease as the waist diameter decreases. On the other hand, when the waist diameter of the THBF is sufficiently small, both Sagnac and modal interferences are simultaneously generated, with the former only sensitive to temperature and the latter sensitive to both temperature and strain. The proposed THBF Sagnac interferometer enables simultaneous measurement of temperature and strain variations, with the strain-insensitive characteristic of Sagnac interference facilitating the discrimination between temperature and strain variations.
Article
Optics
Siti Halma Johari, Tiu Zian Cheak, Hazli Rafis Abdul Rahim, Mohd Hafiz Jali, Haziezol Helmi Mohd Yusof, Md Ashadi Md Johari, Moh Yasin, Sulaiman Wadi Harun
Summary: A relative humidity sensor using a plastic optical fiber coated with zinc oxide nanorods was fabricated, showing improved sensitivity and resolution compared to conventional sensors. The sensor exhibited excellent repeatability properties and demonstrated high performance as an RH sensor.
Article
Engineering, Electrical & Electronic
Yating Yi, Yuxuan Jiang, Haiyan Zhao, Gilberto Brambilla, Yaxian Fan, Pengfei Wang
Summary: An optical fiber humidity sensor based on the Vernier effect is proposed in this paper, which utilizes a microfiber knot resonator (MKR) nested U-shaped Mach-Zehnder (MZ) interferometer. By superimposing the comb-like transmission spectra of the MKR and MZ interference, the humidity measurement is achieved. Experimental results demonstrate that this sensor has high sensitivity, wide measurement range, and fast response time.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Chemistry, Analytical
Hongyin Pan, Chen Yang, Wei Zheng, Xianghong Liu, Yong Wan, Jun Zhang
Summary: A gas sensor based on porous Co3O4 thin films decorated by dual Pt/Rh catalysts is demonstrated for efficient NO2 detection in humid environment. The sensor exhibits high response and moisture resistance due to the three-dimensional ordered microstructure of the Co3O4 thin films and the loading of Pt/Rh catalysts by atom layer deposition (ALD). With optimized ALD Pt and Rh thickness, the sensor shows fast response/recovery speed, a low detection limit and the capability to operate under high humidity.
SENSORS AND ACTUATORS B-CHEMICAL
(2023)
Article
Engineering, Electrical & Electronic
H. Ahmad, M. U. M. Ithnahaini, M. Z. Samion, M. F. Ismail, M. K. A. Zaini, S. A. Reduan
Summary: This research demonstrated a multiwavelength erbium-ytterbium co-doped double-clad fiber laser using two-mode and four-mode fibers as comb filters. The laser generated stable lasing lines with different spacings and high output powers. The long-term stability test showed small wavelength drifts and power fluctuations for both lasers. This work proposes a stable high-power multiwavelength fiber laser with improved output power and efficiency.
IEEE JOURNAL OF QUANTUM ELECTRONICS
(2023)
Article
Optics
H. N. A. Ali, N. Arsad, N. F. Zulkipli, A. H. A. Rosol, M. C. Paul, M. Yasin, S. W. Harun
Summary: This study demonstrates a pulsed Brillouin erbium fiber laser (BEFL) operating at kHz regime, which provides narrow linewidth and high coherence. By controlling the pump power, stable kHz pulse emission can be achieved.
Article
Engineering, Electrical & Electronic
H. Ahmad, M. K. A. Zaini, M. Z. Samion
Summary: Polymer-coated FePS3 arc-shaped fiber was used for four-wave mixing (FWM) as a nonlinear device with high conversion efficiency and large wavelength tuning range. The device's performance was enhanced by overlaying low refractive index polymer on the arc-shaped fiber, making it suitable for integration in optical network applications.
OPTICAL AND QUANTUM ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Ahmed Shakir Al-Hiti, Hiba Hassan, M. Yasin, S. W. Harun
Summary: We have successfully demonstrated a reliable and simple passively Q-switched Thulium-doped fiber laser (TDFL) utilizing tungsten oxide (WO3) as a saturable absorber (SA). The Q-switched TDFL pulses operate at a central wavelength 1960.2 nm with narrow bandwidth, short pulse duration, high repetition rate, output power, and pulse energy.
OPTICAL FIBER TECHNOLOGY
(2023)
Article
Clinical Neurology
Hani Chanbour, Lakshmi Suryateja Gangavarapu, Jeffrey W. Chen, Gabriel A. Bendfeldt, Iyan Younus, Mahmoud Ahmed, Steven G. Roth, Leo Y. Luo, Silky Chotai, Amir M. Abtahi, Byron F. Stephens, Scott L. Zuckerman
Summary: This study aims to investigate the incidence of unplanned readmission, identify associated risk factors, and determine the impact of unplanned readmission on long-term outcomes in patients undergoing surgery for cervical spine metastases. The results showed that 15% of patients experienced unplanned readmission, with 33% for surgical reasons and 67% for medical reasons. Preoperative radiation was associated with increased unplanned readmission rate, but readmission had no association with overall survival or local recurrence.
WORLD NEUROSURGERY
(2023)
Article
Physics, Multidisciplinary
H. Ahmad, B. Nizamani, M. Z. Samion, A. D. Azam, N. Yusoff
Summary: Metal phosphates are cost-effective inorganic materials with potential applications in energy storage and optoelectronic devices. This study demonstrates the synthesis of zinc phosphate and its use as a saturable absorber for a wavelength-tunable mode-locked laser at 1.9 μm. The mode-locked laser achieved soliton pulses with center wavelength tunability from 1893 to 1898.4 nm and pulse durations ranging from 1.12 to 1.4 ps.
Article
Physics, Multidisciplinary
Harith Ahmad, Kirubhashni Loganathan, Norazriena Yusoff
Summary: This study used a Graphene/Zinc Oxide (G/ZnO) nanocomposite to generate mode-locked pulses in Thulium/Holmium-doped fiber (THDF). The sol-gel method was used to synthesize ZnO particles decorated with graphene sheets. The G/ZnO nanocomposite solution was deposited onto an arc-shaped fiber acting as the saturable absorber (SA) device. By incorporating the fabricated SA into the THDF laser cavity, stable mode-locked pulses were produced at a threshold pump power of 274.3 mW with a center wavelength of 1895.11 nm, fundamental frequency of 11.82 MHz, and a pulse duration of 1.7 ps.
Article
Optics
A. Ghosh, H. N. A. Ali, N. Arsad, U. K. Samanta, S. Das, A. Dhar, A. H. A. Rosol, M. Yasin, S. W. Harun, M. C. Paul
Summary: We demonstrate Q-switched pulse generation at the 1562.5 nm region by using a 70 cm long erbium-bismuth co-doped alumina-germania-hafnium-yttria silica glass-based fiber as a gain medium in a simple ring resonator configured without saturable absorber and optical isolator devices. The Q-switching was obtained based on a stimulated Brillouin scattering assisted four-wave mixing effect in the gain medium, which induced the intensity modulation mechanism. Stable Q-switched operation of a hafnia-bismuth-erbium co-doped fiber laser was obtained at a pump power range of 129-319 mW with the repetition rate varying from 45.9 kHz to 89.3 kHz and the pulse width ranging from 8.8 mu s to 3.58 mu s. A maximum pulse energy of 26.9 nJ at an average output power of 2.4 dBm was achieved. This demonstrates a new passive technique based on a highly nonlinear gain medium for realizing Q-switched all-fiber laser sources.
Article
Optics
S. A. Anuar, M. F. A. Rahman, A. M. M. Nasir, A. A. Latiff, M. F. M. Rusdi, S. W. Harun
Summary: A self-induced Q-switched erbium-doped fiber laser operating at 1563 nm was achieved by integrating a passive modulator based on tantalum aluminum carbide (Ta2AlC) MAX phase film embedded into polyynyl alcohol. The laser produced stable pulses with excellent signal quality, and reached maximum average output power, pulse energy, and peak power within a specific pump power range.
Article
Optics
Muhammad Syamil Mohd Sa'ad, Harith Ahmad, Mohamad Ashraff Alias, Muhammad Khairol Annuar Zaini, Muhamad Zharif Samion, Kenneth T. V. Grattan, B. M. Azizur Rahman, Gilberto Brambilla, Lim Kok Sing, Sulaiman Wadi Harun, Leonard Bayang, Siti Aisyah Reduan, Kavintheran Thambiratnam, Mohd Zamani Zulkifli, Mohammad Faizal Ismail
Summary: This paper presents the design and fabrication of an optical-based pressure sensor that utilizes a fiber Bragg grating (FBG) as the pressure sensing mechanism. The sensor can convert the pressure applied to its surface into a wavelength shift. Laboratory testing shows a high sensitivity, and field testing confirms its effectiveness in soil monitoring applications.
OPTICAL ENGINEERING
(2023)
Article
Mathematics, Applied
Naeem Ahmad, E. S. Kamel, Sid Ahmed Ould Ahmed Mahmoud
Summary: In this work, we extend the concept of n-quasi-p-isometric operators from a single operator to multi-dimensional operators. We present new interesting results of these tuples of operators, which expand upon recently published works that focus on a single operator.
Article
Optics
Cheong-Weng Ooi, Kok-Sing Lim, Kuan-Huei Ng, Wu-Yi Chong, Soon-Xin Gan, Boon-Tong Goh, Harith Ahmad
Summary: This article presents the spectral properties of a Ge2Sb2Se4Te1 (GSST)-coated tilted fiber Bragg grating in response to changes in the surrounding refractive index (SRI). The variations of cladding mode resonance amplitudes and wavelengths under two orthogonal polarization modes are analyzed and validated with simulation results. The introduction of a high index coating induces non-degeneracy in the cladding modes, which gradually diminishes as SRI increases. The SRI sensitivities of s-polarized modes are substantially reduced and become 20 times lower than p-polarized modes. The findings also establish the relationship between cladding resonance amplitudes, the imaginary part of effective refractive indices, and evanescent field intensity distributions.
Article
Mining & Mineral Processing
Khaled Yassin, Mahmoud Ahmed, Mohamed Gamal Eldin Khalifa, Ayman Aly Hagrass
Summary: Dry magnetic separation is an effective technique for reducing iron in feldspar, especially in arid regions with limited water resources. This study conducted dry magnetic separation experiments on feldspar ore in the Wadi Umm Harjal area in Egypt, successfully removing iron content and improving the quality of the sample to meet industry specifications.
ARCHIVES OF MINING SCIENCES
(2023)
Article
Multidisciplinary Sciences
Sid Ahmed Ould Ahmed Mahmoud, Naeem Ahmad
Summary: In this paper, new classes of operators related to polynomially normal operators are introduced. The first class is m-quasi polynomially normal operators, which includes polynomially normal operators studied in recent papers. A bounded linear operator S is said to be an m-quasi polynomially normal operator if there exists a nontrivial polynomial P and a natural number m satisfying a certain equation. The second class is called polynomially C-normal operators, which includes C-normal operators studied in other papers. An operator S is called a polynomially C-normal operator if there exists a nontrivial polynomial P and a conjugation operator C satisfying a certain equation. The paper presents a detailed study of certain properties of the first class of operators and gives an introduction to the second class.
IRANIAN JOURNAL OF SCIENCE
(2023)
Article
Management
Mahmoud Ahmed
Summary: This paper investigates how women's representation on corporate boards affects financial reporting quality. The study finds that increasing women's representation on boards reduces undue CEO influence over the board and improves accounting quality. However, this effect is only significant in the long run and is attenuated for larger firms and larger boards.
INTERNATIONAL JOURNAL OF DISCLOSURE AND GOVERNANCE
(2023)
