RETRACTED ARTICLE: A new structure and modeling of a three-axis MEMS capacitive accelerometer with high dynamic range and sensitivity

Microsystem Technologies - In this paper, a three-axis capacitor accelerator has been analyzed, modeled and optimized using micro-electromechanical systems technology. In the proposed structure,...     

One year soy protein supplementation has positive effects on bone formation markers but not bone density in postmenopausal women

Background  

Although soy protein and its isoflavones have been reported to reduce the risk of osteoporosis in peri- and post-menopausal women, most of these studies are of short duration (i.e. six months). The objective of this study was to examine if one year consumption of soy-containing foods (providing 25 g protein and 60 mg isoflavones) exerts beneficial effects on bone in postmenopausal women.     

A novel high tuning ratio MEMS cantilever variable capacitor

This paper presents a novel cantilever-type MEMS variable capacitor with high tuning ratio. In previous works, the cantilever is used as a switch but in our design, it is applied as a variable capacitor. For increasing the maximum achievable capacitance of the cantilever, the suspended capacitive plate should be moved as parallel with fixed plate. The parallel movement can be obtained using the novel structure which utilized two additional lateral beams. Also to overcome the pull-in phenomenon in new structure, the different membrane thickness technique is used. The novelty of our design is adding the lateral beams to make parallel movement of the suspended plate to increase the variable capacitor of the cantilever. The new device is designed on a thick silicon substrate with a thin poly silicon membrane. The results show the tuning range of tunable capacitor with initial capacitance of 560.1 fF can be improved from 6:1 for conventional cantilever to 22.5:1 for the new cantilever. In other words the capacitance tuning range increased three times.     

A high sensitive MEMS capacitive fingerprint sensor using slotted membrane

In this paper a novel single-chip microelectromechanical systems (MEMS) capacitive fingerprint sensor with slotted membrane is developed to improve the sensitivity. The capacitive sensor consists of a thin, flexible membrane and a rigid back plate with air gap. In this study with making slots in upper electrode to decrease the mechanical stiffness of the membrane, using proportional T-shaped protrusion on diaphragm in order to concentrate the force from finger ridges, making holes in lower electrode to reduce the air damping and using low stress material for diaphragm, we have been succeeded to design a novel MEMS fingerprint sensor with high sensitivity compared with the previous works (Sato et al., IEEE Trans Electron Devices 52:1026–1032, 2005; Damghanian and Majlis, 2008 IEEE International Conference on Semiconductor Electronics (ICSE 2008), pp 634–638 2008). The behaviors of the fingerprint sensor with clamped and slotted membranes are analyzed using the finite element method (FEM). The results yield a sensitivity of 1.44 fF/Mpa for the clamped and 3.22 fF/Mpa for the slotted fingerprint sensor with a 50 × 50 μm² diaphragm. The sensitivity of the slotted structure is increased 2.236 times.     

Longitudinal jerk and celeration as measures of safety in bus rapid transit drivers in Tehran

Abstract

Traditionally, analysis of individual differences in road traffic crash risk has relied on after the fact crash data. Nowadays with the help of technologies like GPS, new measures are developed to assess driving risk, inferred from naturalistic driving behaviour of drivers. In this study, two main ways of modelling driver behaviour in naturalistic driving research were discussed and compared to each other. For this purpose, 176 Bus Rapid Transit (BRT) drivers were investigated during their normal driving on Tehran BRT routes. Their speed was continuously recorded by a smart phone app from which was derived deceleration, jerk and celeration measures. Analysis showed that all of the proposed measures had positive correlations with culpable crashes and that one of the jerk variables yielded the highest correlation. Measurements of speed derivatives like jerk and celeration can help to identify dangerous driving styles in public transportation and reduce the number of crashes. Although the results of this study are encouraging, further studies for longer periods are needed to improve the reliability of the measures.     

Doping effects of Co on exo-hydrogenated narrow single-walled carbon nanotubes

Density functional theory (DFT) calculations with the generalized gradient approximation (GGA) were employed for a systematic study of electronic structure and morphologic characteristics of bare and exo-hydrogenated Co-doped single walled carbon nanotubes (CNTs). Two internally and one externally doping configurations for the cobalt adatoms were investigated. Binding energies, bond lengths and angles, under full and half converge of the adsorbed hydrogen atoms were calculated for both cases. Effect of hybridization between the Co-3d and the H-s orbitals showed that the exo-hydrogenated CNTs with full and half coverage cases would be stable in the internally doped Co atom systems; whereas, the stability of the hydrogenated systems under externally doped Co adatom was not trivial. In general, for the externally Co-doping, the Co atoms can act as additional adsorbents so the amount of total adsorbed hydrogens could be varied substantially; whereas, for the internally Co-doping the nature of the exo-hydrogenation (being atomic or molecular) shows nanotube's chirality dependent.     

Milk Thistle Seed Oil Constituents from Different Varieties Grown in Iran

In this study, fatty acids, phytosterol classes and tocopherols composition of Milk thistle seeds oil were determined at four varieties grown in Ardebil-Iran. The four varieties consisted of two modified foreign varieties—Budakalaszi (originally from Hungary) and the CN-seed variety (originally from England) and two native varieties, namely Khoreslo and Babak Castle. The oil content of the seeds ranged from 26 to 31%. Among the fatty acids, linoleic acid had the highest percentage (50–54%) followed by oleic acid (23–29%) and palmitic acid (7–8%). This is the first detailed report on the phytosterol classes of milk thistle seeds oil. The 4-Desmethylsterol class was predominant (1,800–2,200 μg/g) followed by 4,4′-dimethylsterols (50–85 μg/g) and 4-monomethylsterols (26–35 μg/g). The α-, β-, γ-, and δ-tocopherols ranged from 187 to 465, 10 to 51, 9 to 12, and 18 to 80 μg/g oil, respectively. Based on the results obtained, the extracted oil from milk thistle seeds are rich in essential fatty acids, sterols and vitamin E and can be an attractive candidate for use in food preparation mixed with other vegetable oils or alone.     

Geochemical characteristics of upper Jurassic carbonate reservoir bitumen in the Eastern Kopeh-Dagh,NE Iran

Geochemical characteristics of solid bitumen in Upper Jurassic carbonate reservoir are investigated. Aromatic maturity parameters indicate peak to late oil window level of maturity for the bitumen samples. Regular sterane distributions, conical variable (CV), plots of δ¹³C_Sat versus δ¹³C_Aro and Pr/nC₁₇ against Ph/n_C18, predominance of C₂₃ tricyclic terpane, ratios of steranes/hopanes and C₂₃/C₂₁ tricyclic terpane indicate charging from clastic-rich anoxic marine source rocks. Ratios of C₂₉/C₃₀ hopane, Ts/Ts+ Tm, C₂₄ tetracyclic terpane/C_20-26 tricyclic terpanes and plot of C₂₂/C₂₁ versus C₂₄/C₂₃ tricyclic terpanes show influences of carbonate/marl facies. All these would throw crucial guiding light on the interpretation of the future exploration.