ORCID Profile
0000-0003-2030-8881
Current Organisation
University Technology MARA
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Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2022
Publisher: IEEE
Date: 06-2016
Publisher: Mineralogical Society
Date: 04-2017
DOI: 10.1180/MINMAG.2016.080.100
Abstract: Steinmetzite, ideally Zn 2 Fe 3+ (PO 4 ) 2 (OH)·3H 2 O, is a new mineral from the Hagendorf-Süd pegmatite, Hagendorf, Oberpfalz, Bavaria, Germany. Steinmetzite was found in a highly oxidized zone of the Cornelia mine at Hagendorf-Süd. It has formed by alteration of phosphophyllite, involving oxidation of the iron and some replacement of Zn by Fe. Steinmetzite lamellae co-exist with an amorphous Fe-rich phosphate in pseudomorphed phosphophyllite crystals. The lamellae are only a few μm thick and with maximum dimension ∼50 μm. The phosphophyllite pseudomorphs have a milky opaque appearance, often with a glazed yellow to orange weathering rind and with lengths ranging from sub-mm to 1 cm. Associated minerals are albite, apatite, chalcophanite, jahnsite, mitridatite, muscovite, quartz and wilhelmgümbelite.Goethite and cryptomelane are also abundant in the oxidized zone. The calculated density is 2.96 g cm –3 . Steinmetzite is biaxial (–) with measured refractive indices α = 1.642(2), β = 1.659 (calc.), γ = 1.660(2) (white light). 2V(meas) = 27(1)° orientation is Y ≈ b , X ^ c ≈ 27°, with crystals flattened on {010} and elongated on [001]. Pleochroism shows shades of pale brown Y X ≈ Z . Electron microprobe analyses (average of seven crystals) with Fe reported as Fe 2 O 3 and with H 2 O calculated from the structure gave ZnO 31.1, MnO 1.7, CaO 0.5, Fe 2 O 3 21.9, Al 2 O 3 0.3, P 2 O 5 32.9, H 2 O 14.1 wt.%, total 102.5%. The empirical formula based on 2 P and 12 O, with all iron as ferric and OH–adjusted for charge balance is Zn 1.65 Fe 1.19 3+ Mn 0.11 2+ Ca 0.03 Al 0.02 3+ (PO 4 ) 2 (OH) 1.21 ·2.79H 2 O. The simplified formula is Zn 2 Fe 3+ (PO 4 ) 2 (OH)·3H 2 O.Steinmetzite is triclinic, P 1̄, with unit-cell parameters: a = 10.438(2), b = 5.102(1), c = 10.546(2) Å, α = 91.37(2), β = 115.93(2) and γ = 94.20(2)°. V = 502.7(3) Å 3 , Z = 2. The strongest lines in the powder X-ray diffraction pattern are [ d obs in Å ( I ) ( hkl )] 9.313(65) (100), 5.077(38) (010), 4.726(47) (002), 4.657(100) (200), 3.365 (55) (3̄02), 3.071(54) (11̄2) and 2.735(48) (3̄1̄2). The structure is related to that of phosphophyllite.
Publisher: MDPI AG
Date: 14-09-2021
DOI: 10.3390/S21186163
Abstract: The large number of Internet-of-Things (IoT) devices that need interaction between smart devices and consumers makes security critical to an IoT environment. Biometrics offers an interesting window of opportunity to improve the usability and security of IoT and can play a significant role in securing a wide range of emerging IoT devices to address security challenges. The purpose of this review is to provide a comprehensive survey on the current biometrics research in IoT security, especially focusing on two important aspects, authentication and encryption. Regarding authentication, contemporary biometric-based authentication systems for IoT are discussed and classified based on different biometric traits and the number of biometric traits employed in the system. As for encryption, biometric-cryptographic systems, which integrate biometrics with cryptography and take advantage of both to provide enhanced security for IoT, are thoroughly reviewed and discussed. Moreover, challenges arising from applying biometrics to IoT and potential solutions are identified and analyzed. With an insight into the state-of-the-art research in biometrics for IoT security, this review paper helps advance the study in the field and assists researchers in gaining a good understanding of forward-looking issues and future research directions.
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