Abstract
The paper introduces a SU-8 dielectric
µ
-bridge based polymer microelectromechanical systems (MEMS) Pirani gauge which can be employed for hermetic characterization of packaged electronic ...sensors. The
µ
-bridge structure is adopted due to its simplicity in fabrication and lower footprint, which makes it feasible for heterogeneous integration. Further, the integration of SU-8 polymer with the active thermistor offers superior thermal isolation from the substrate and extends the dynamic range. Before fabricating the actual device, the SU-8 based
µ
-bridge is optimized for stress-free release. A stress engineering is performed and thermal processing of SU-8 is optimized. The measurement results reveal that the removal of quenching from the baking steps leads to the successful fabrication of freely suspended
µ
-bridge with SU-8 polymer as a structural layer. A quantitative comparison of the proposed gauge is established by comparing the gauge performance with conventional dielectric materials like silicon dioxide (SiO
2
), silicon nitride (Si
3
N
4
), and aluminum oxide (Al
2
O
3
). The fabricated SU-8 polymer-based MEMS Pirani gauge with a 40
µ
m × 7
µ
m footprint can be used for hermetic characterization from 30 Pa to 10
5
Pa and is an ideal candidate for heterogeneous integration.
Objectives. Clubfoot has been an unsolved clinical challenge for the orthopedic surgeons and it is one of the congenital deformities in children. Around one lakh (100000) babies born with clubfoot ...deformity throughout world each year, out of which 80% cases occur in developing countries. Material and methods. A total of 23 children (32 feet) in children below 2 years of age with unilateral or bilateral idiopathic clubfoot deformity who presented to outpatient department between September 2016 to September 2018 were included in the study and were treated conservatively by use of Ponseti method. Results. The mean age of presentation was 17.9 weeks, with male to female ratio – 2.28:1. The mean initial Pirani score was 5.26±2.89. The relationship between number of casts and the respective Pirani score was assessed using the Spearmen’s rank correlation coefficient and a positive correlation was found. The mean number of casts required was 6.43 and in 68.75% feet Tendo Achilles tenotomy was needed. Conclusion. Ponseti method is a very effective method to treat idiopathic clubfoot. It avoids the complication of surgery and gives a painless, mobile, normal looking, functional foot and allows fairly good mobility.
Objectives. Clubfoot has been an unsolved clinical challenge for the orthopedic surgeons and it is one of the congenital deformities in children. Around one lakh (100000) babies born with clubfoot ...deformity throughout world each year, out of which 80% cases occur in developing countries. Material and methods. A total of 23 children (32 feet) in children below 2 years of age with unilateral or bilateral idiopathic clubfoot deformity who presented to outpatient department between September 2016 to September 2018 were included in the study and were treated conservatively by use of Ponseti method. Results. The mean age of presentation was 17.9 weeks, with male to female ratio – 2.28:1. The mean initial Pirani score was 5.26±2.89. The relationship between number of casts and the respective Pirani score was assessed using the Spearmen’s rank correlation coefficient and a positive correlation was found. The mean number of casts required was 6.43 and in 68.75% feet Tendo Achilles tenotomy was needed. Conclusion. Ponseti method is a very effective method to treat idiopathic clubfoot. It avoids the complication of surgery and gives a painless, mobile, normal looking, functional foot and allows fairly good mobility.
This article presents a titanium-nitride composite (TiN-C)-based complementary metal-oxide- semiconductor microelectromechanical system (CMOS-MEMS) Pirani gauge integrated into the back-end-of-line ...(BEOL) layers. A microbeam architecture is utilized as the sensing element consisting of a stack of TiN and SiO<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula>. The structure utilizes the sandwiched (TiN/AlCu/TiN) metal line configuration to craft the suspended sensing element having a nanogap from the substrate. TiN serves as the heating element in the sensing element, while SiO<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula> provides mechanical support to the structure. Gauges with lengths varying from 60 to 90 <inline-formula> <tex-math notation="LaTeX">\mu</tex-math> </inline-formula>m are proposed, while the width is kept the same, i.e., 4 <inline-formula> <tex-math notation="LaTeX">\mu</tex-math> </inline-formula>m. Since the BEOL-integrated MEMS devices are prone to suffer from residual stress, an optical profilometer analysis is performed to quantify the effective value of the suspended gap. Furthermore, temperature profiles of the proposed designs are evaluated using COMSOL Multiphysics. Finally, the fabricated gauges are tested for pressure-dependent response from 1 to 10<inline-formula> <tex-math notation="LaTeX">^{\text{6}}</tex-math> </inline-formula> Pa and a performance comparison is established. In the monolithic CMOS-MEMS implementation, a lower detection limit of 15.5, 12.3, 10.3, and 8.3 Pa is obtained for different gauge lengths, while the upper detection range is the same, i.e., 10<inline-formula> <tex-math notation="LaTeX">^{\text{6}}</tex-math> </inline-formula> Pa.
The treated clubfoot children are often evaluated clinically during follow-up. However, patient reported outcomes (PROM) are seldom analysed for these children. We investigated 87 idiopathic clubfoot ...children (140 feet) treated by the Ponseti method and followed minimum 5 years to study their clinical outcomes and PROM.
This was a cross-sectional study, based on evaluating treated clubfoot children clinically (Pirani score) and PROM (Oxford Ankle and Foot Questionnaire – Parent Version) and comparing them with the age-matched healthy controls (n = 60). The questionnaire has four main domains related to the child's physical, school and play, emotional and footwear profile. The children having persistent deformity (residual/relapse) were specifically studied for their PROM scores.
The mean child age at initial treatment was 2.3 months and the mean follow-up duration was 6.9 years. The PROM score of clubfoot children was statistically lower than the healthy controls (p < 0.001). Of the individual domains, the physical domain was the most affected. On calculating the Pirani scores, 10 out of 140 feet (7 %) had some form of persistent deformity. The children with persistent deformity had lower Oxford scores than healthy children or those with corrected feet. The physical domain followed by the emotional domain scored low when persistent deformity was present.
Most children (98 %) had a plantigrade foot following Ponseti treatment at follow-up. However, PROM score of the clubfoot children did not correspond to the clinical outcome. Persistent deformity, even minor, was a cause of parental concern and resulted in a low PROM score.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this paper, we present a surface micromachined Pirani vacuum gauge integrated with a stacked temperature sensor using CMOS-MEMS technology. The proposed Pirani gauge features a <inline-formula> ...<tex-math notation="LaTeX">2.23~\mu \text{m} </tex-math></inline-formula> thick suspended microheater, which is positioned between two designed heat sinks. The upper and lower gap spacing between the heat sink and the microheater is <inline-formula> <tex-math notation="LaTeX">0.53~\mu \text{m} </tex-math></inline-formula>, which is made by the surface etching of two metal films. Additionally, a temperature sensor based on a poly-Si resistor is directly integrated into the lower heat sink. The temperature sensor shows a sensitivity of 45 ohm/°C over a linear range of 10~60 °C, while its measurement error is less than 0.11 °C in the worst case. The Pirani gauge achieves a high sensitivity of 0.96 V/Dec under fine vacuum conditions, and its heating power is less than 8.3 mW in the vacuum range of 0.8~14000 Pa. Moreover, the measured output of the Pirani gauge closely matches the proposed semi-empirical model, while the noise measurements indicate that the sensor has a resolution as low as <inline-formula> <tex-math notation="LaTeX">6.4\times 10 ^{\mathbf {-3}} </tex-math></inline-formula> Pa in very fine vacuum conditions. This integrated Pirani gauge and temperature sensor system, in combination with its high performance, makes it a promising sensing node for vacuum and temperature monitoring in semiconductor equipment. 2023-0184
This work reports a thin-film encapsulated package with porous alumina as the capping layer and titanium as a pore-sealing getter. The titanium-gold film seals the thin film package and acts as the ...getter. Since the getter is not exposed to the elements, fouling of the getter is prevented. EDX measurements confirm that the getter material did not penetrate the package through the nanopores. The process is a low thermal budget process, with the getter activation (300 <inline-formula> <tex-math notation="LaTeX">^{\circ}</tex-math> </inline-formula>C for 1 hour) being the only step where the temperature is raised. A Silicon Pirani gauge was used to monitor the pressure changes inside the sealed cavity. After the getter activation, a decrease in the pressure from 50 <inline-formula> <tex-math notation="LaTeX">\mu</tex-math> </inline-formula>Torr to 3.9 <inline-formula> <tex-math notation="LaTeX">\mu</tex-math> </inline-formula>Torr was seen for the first few days, and no noticeable change afterward. The hermeticity of the thin-film encapsulated package was examined, and the vacuum level inside the package remained the same for the last 510 days. In addition to providing a stable hermetic package, the getter may be activated in-circuit by resistive heating in case of pressure increases after many years of operation. 2023-0034
The aim of this study was to track the correction of individual components of Pirani scoring system (PSS) over the manipulation and tenotomy phase of Ponseti casting method in idiopathic clubfoot. ...Additionally, non-zero PSS scores were analysed to find out the residual deformities.
The included feet were assessed initially according to the six component PSS. The individual scores of each component of midfoot and hindfoot were scored at each visit till the final follow up. The final scoring was done before the start of the bracing phase of the feet (with or without tenotomy).
Evaluation was performed for 42 feet in 28 infants (14 bilateral) with mean age of 42.5 ± 39.2 days (range, 15-150 days). All the six components of PSS showed a significant change from the first cast till the pre tenotomy cast. Post tenotomy, there was a significant change in the scores of posterior crease (0.4 ± 0.2 to 0.1 ± 0.1, p < 0.001) and rigid equinus (0.8 ± 0.3 to 0.1 ± 0.2, p < 0.001). 66.7 % (28/42) of the feet had an abnormal empty heel sign of either 0.5 22/42 (52.3 %) or 1 6/42 (14.4 %) at initiation of bracing.
The individual components of Pirani scoring system changed to a variable extent as the treatment progressed. Curvature lateral border and talar head reached normalcy prior to tenotomy. Posterior crease and rigid equinus showed a significant reduction after tenotomy. The non-zero empty heel component may require careful interpretation both post treatment and during follow ups.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this article, we report a wafer-level packaged Pirani vacuum gauge using the proprietary InvenSense CMOS MEMS technology. The micro Pirani vacuum gauge features three serpentine-shaped molybdenum ...thermistors on the suspended silicon-on-insulator (SOI) bridges, while the wiring gap of each serpentine-shaped silicon microbridge is 1.6 <inline-formula> <tex-math notation="LaTeX">{ {\mu }}\text{m} </tex-math></inline-formula>. For the vacuum range of <inline-formula> <tex-math notation="LaTeX">5\times 10^{-{4}} </tex-math></inline-formula>-760 Torr, the CMOS MEMS Pirani gauge configured with a constant temperature interface circuit achieves a sensitivity of 0.414 V/Torr in a very fine vacuum regime, while its heating power is less than 21.3 mW. Moreover, the measured output of the micro Pirani gauge shows good agreement with a semi-empirical model, while the model predicts that the proposed Pirani gauge can measure a vacuum pressure as low as <inline-formula> <tex-math notation="LaTeX">2.6\times 10^{-{4}} </tex-math></inline-formula> Torr. The performance achieved by this Pirani vacuum gauge combined with its high level of integration makes it a promising Internet of Things (IoT) sensing node for vacuum monitoring in the industry.
Physical foundations for relativistic spacetimes are revisited in order to check at what extent Finsler spacetimes lie in their framework. Arguments based on inertial observers (as in the foundations ...of special relativity and classical mechanics) are shown to correspond with a double linear approximation in the measurement of space and time. While general relativity appears by dropping the first linearization, Finsler spacetimes appear by dropping the second one. The classical Ehlers–Pirani–Schild approach is carefully discussed and shown to be compatible with the Lorentz–Finsler case. The precise mathematical definition of Finsler spacetime is discussed by using the space of observers. Special care is taken in some issues such as the fact that a Lorentz–Finsler metric would be physically measurable only on the causal directions for a cone structure, the implications for models of spacetimes of some apparently innocuous hypotheses on differentiability, or the possibilities of measurement of a varying speed of light.