An Efficient Design of the Piezoresistive Pressure Sensor Applied for Micro Aerial Vehicle

In this research, the developing process of a piezoresistive pressure sensor working in the atmosphere environment applied in micro aerial vehicle using the MEMS fabrication method is introduced. The sensor consists of four Au/Cr piezoresistors in a Wheatstone bridge configuration on a wet oxidized silicon diaphragm. To fabricate the sensor, three lithographic steps were conducted: the first one is to define the resistors and Au/Cr lines/pads, the second and the third ones are to determine the width and the thickness of the square SiO2/Si diaphragm, respectively. The sensor diaphragm shape and thickness were defined by the anisotropic etching of Si in tetramethylammonium hydroxide (TMAH) solution, and the resistors array are formed by sputtering and wet etching method. The sensor size is ~6000 µm by 6000 µm. The sensor output voltage was measured for various applied pressure levels from 0 to 1.2 bar with 5V voltage supply. The fabricated sensor also exhibits a sensitivity of 50.01 mV/bar

Comportamento sperimentale di cuscinetti portanti lubrificati operanti a bassi numeri di Sommerfeld

In questa memoria viene descritto il comportamento sperimentale di un cuscinetto cilindrico portante lubrificato in condizioni di funzionamento critiche, ovvero a velocità di rotazione molto basse ed in presenza di elevata pressione specifica. Il cuscinetto utilizzato ha diametro nominale di 160 mm e lunghezza pari a 145 mm. La velocità di rotazione considerata è pari a 60 rpm (1 Hz), mentre i carichi applicati in direzione verticale variano da 20 kN a 350 kN, il che corrisponde a numeri di Sommerfeld variabili tra 0,1314 e 0,0086. Verranno presentati e discussi i dati ottenuti per la posizione di equilibrio statico, per la pressione idrodinamica, per la distribuzione di temperatura e per i coefficienti di rigidezza e smorzamento dinamici

An Efficient Design of the Piezoresistive Pressure Sensor Applied for Micro Aerial Vehicle

In this research, the developing process of a piezoresistive pressure sensor working in the atmosphere environment applied in micro aerial vehicle using the MEMS fabrication method is introduced. The sensor consists of four Au/Cr piezoresistors in a Wheatstone bridge configuration on a wet oxidized silicon diaphragm. To fabricate the sensor, three lithographic steps were conducted: the first one is to define the resistors and Au/Cr lines/pads, the second and the third ones are to determine the width and the thickness of the square SiO2/Si diaphragm, respectively. The sensor diaphragm shape and thickness were defined by the anisotropic etching of Si in tetramethylammonium hydroxide (TMAH) solution, and the resistors array are formed by sputtering and wet etching method. The sensor size is ~6000 µm by 6000 µm. The sensor output voltage was measured for various applied pressure levels from 0 to 1.2 bar with 5V voltage supply. The fabricated sensor also exhibits a sensitivity of 50.01 mV/bar

Analisi teorica e sperimentale dell’effetto della direzione del carico in cuscinetti a pattini oscillanti reali

I cuscinetti portanti a pattini oscillanti sono ampiamente utilizzati nelle macchine rotanti per velocità elevate e carichi sia bassi sia elevati. Data l’importanza di questo componente delle macchine rotanti, molti autori hanno pubblicato diversi studi, teorici e sperimentali, per valutare l’effetto dei giochi, della temperatura del lubrificante, della portata dell’olio e di diversi effetti termici sul comportamento di questo tipo di cuscinetto. Tuttavia, le indagini sull’influenza della direzione di carico sulle proprietà dei cuscinetti a pattini oscillanti sono spesso molto limitate e non considerano le geometria reale del cuscinetto. In questo articolo verrà presentata un’analisi teorica e sperimentale degli effetti delle direzione del carico nei cuscinetti reali a pattini oscillanti

Application of bluetooth mesh network in multi-device system management

Currently, the application of the Internet of Things (IoT) in the industrial sector to improve the productivity and efficiency of industrial processes is no longer unfamiliar. However, for a wireless control system to operate reliably and stably even without the Internet, additional issues regarding energy and alternative control options need to be addressed. In this article, the authors have investigated the application of Bluetooth Mesh networks in industrial production systems. In a manufacturing facility, Bluetooth devices are installed on machinery and can exchange data with each other through a gateway device that serves as a data receiver for the Bluetooth devices. Additionally, the system can be remotely monitored and controlled through a Web server. Implementing this system in production enables industrial companies to digitize processes, transform business models, and enhance performance and productivity

Design of a fast cassette autoclaves for medical devices

Ensuring patient safety in healthcare necessitates the sterilization of medical devices. However, traditional autoclaves are impractical for certain medical settings due to their size, bulkiness, and time-consuming nature. To address this, a compact and portable alternative called a cassette autoclave was developed. This paper presents the design and manufacturing process of a high-speed cassette autoclave for medical devices. The autoclave features small dimensions, lightweight construction, and user-friendly operation. It achieves remarkable speed, sterilizing devices in approximately 3.5 minutes. Made of durable stainless steel, it includes a digital control panel for seamless management. Extensive testing and validation ensure compliance with sterilization standards. The results highlight the autoclave's effectiveness and safety, making a significant contribution to medical device sterilization

Wearable devices for remote monitoring of hospitalized patients with COVID-19 in Vietnam

Patients with severe COVID-19 disease require monitoring with pulse oximetry as a minimal requirement. In many low- and middle- income countries, this has been challenging due to lack of staff and equipment. Wearable pulse oximeters potentially offer an attractive means to address this need, due to their low cost, battery operability and capacity for remote monitoring. Between July and October 2021, Ho Chi Minh City experienced its first major wave of SARS-CoV-2 infection, leading to an unprecedented demand for monitoring in hospitalized patients. We assess the feasibility of a continuous remote monitoring system for patients with COVID-19 under these circumstances as we implemented 2 different systems using wearable pulse oximeter devices in a stepwise manner across 4 departments

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

Static Characteristics of a Tilting Five-Pad Journal Bearing with an Asymmetric Geometry

In this paper, static characteristics of a tilting five‐pad rocker‐backed journal bearing with an asymmetric geometry, i.e., different clearance for each pad, are investigated. A thermo‐elastohydrodynamic (TEHD) model considering the elasticity of the pad and pivot is used for the simulation. The pivot stiffness of each pad obtained by experiment is also introduced in the model. The experimental tests were carried out on a tilting pad journal bearing (TPJB) with a nominal diameter of 100 mm and a length‐to‐diameter (L/D) ratio of 0.7 with load‐between‐pad (LBP) and load‐on‐pad (LOP) arrangements. Several analyses, including numerical simulations and experimental measurements, are implemented in order to obtain the static behaviors of the tiltingpad bearing under variations of rotational speed, amplitude and direction of applied static load, such as clearance distribution profile, static eccentricity, temperature and pressure distribution. The results show that the effect of asymmetric geometry on the static characteristics is not negligible

The Effect of the Pivot Stiffness on the Performances of Five-Pad Tilting Pad Bearings

The role of the pivot flexibility in tilting-pad journal bearings (TPJBs) has become essential, particularly for bearings working at high applied load and relatively high rotor speeds. Predictions from a simple bearing model with rigid pivots show incorrect estimation of the dynamic coecients in comparison with the experimental results. Normally, the more flexible the pad pivot, the lower the dynamic coecients because the stiness of the pivot takes in series with the stiness and damping of the oil film. This paper investigates the influence of pivot stiness on the dynamic force coecients of two dierent five-pad TPJBs as a function of the applied static load and excitation frequency: rocker-backed pivot and spherical pivot bearings. In order to highlight the eect of the pivot stiness in the spherical pivot bearing, displacement restriction components and elastic copper made shims have been used. Firstly, a thermo-elasto-hydrodynamic model for the static and dynamic characteristics of the two bearings is described. This model takes into account the flexibility of both pad and pivot. The pivot stinesses calculated by means of the Hertz theory and those obtained by experiments have been introduced and compared in the model. The clearance profiles of two tested bearing and the shaft center loci obtained by measurement and prediction are also shown. The dynamic coecients of the two bearings obtained from the numerical simulation were compared with the experimental results. By the analysis it can be concluded that the eect of the pivot flexibility on the clearance profile, the shaft locus and on the dynamic coecients is very significant. More important, it is important to estimate the pivot stiness of each single pad using experimental measurements