LPG Concentrations Research Articles

Tau Fibrillation Induced by Heparin or a Lysophospholipid Show Different Initial Oligomer Formation

The protein tau is involved in several neurogenerative diseases such as Alzheimer’s Disease, where tau content and fibrillation have been linked to disease progression. Tau colocalizes with phospholipids and glycosaminoglycans in vivo. We investigated if and how tau fibrillation can be induced by two lysophospholipids, namely the zwitterionic 1-myristoyl-2-hydroxy-sn-glycero-3-phosphocholine (LPC) and the anionic 1-myristoyl-2-hydroxy-sn-glycero-3-phospho-(1′-rac-glycerol) (LPG) as well as the glycosaminoglycan heparin. We used a range of biophysical techniques including small-angle X-ray scattering, Thioflavin T fluorescence, and SDS-PAGE, collecting data at various time points to obtain structural information on each phase of the fibrillation. We find that LPC does not induce fibrillation or interact with tau. Low concentrations of LPG induce fibrillation by formation of small hydrophobic clusters with monomeric tau. At higher LPG concentrations, a core–shell complex is formed where tau wraps around LPG micelles with regions extending away from the micelles. For heparin, loosely associated oligomers are formed rapidly with around ten tau molecules. Fibrils formed with either LPG or heparin show similar final cross-section dimensions. Furthermore, SDS-resistant oligomers are observed for both LPG and heparin. Our study demonstrates that tau fibrillation can be induced by two different biologically relevant cofactors leading to structurally different initial states but similar cross-sectional dimensions for the fibrils. Structural information about initial states prior to fibril formation is important both to gain a better understanding of the onset of fibrillation in vivo, and for the development of targeted drugs that can reduce or abolish tau fibrillation.

Efficient Information Fusion from Environmental Sensors for Near Real-Time IoT Analytics

This research paper explores the world of nearly real time analytics by focusing on methods of combining information obtained from Environmental Sensor data. The study utilized a customized setup consisting of three arrays of sensors connected to Raspberry Pi devices. It. Analyzed a dataset that encompassed various environmental conditions. By utilizing the Random Forest algorithm this research investigated how sensor readings, including temperature, humidity, LPG concentrations, smoke, light intensity and motion detection can be fused together. The methodology used cross-validation to ensure model training while visually presenting the intricate relationships, between environmental parameters. The results demonstrated the performance of the Random Forest model through visualizations showing Out of Bag (OOB) error rates and a comparative analysis of machine learning classifiers. The findings shed light on the potential of combining information from sensors to enable reliable predictions using Environmental Sensor data. This provides a foundation for advancements in analytics and applications related to environmental monitoring.

УСТАНОВКА ПРЕДОТВРАЩЕНИЯ ОБРАЗОВАНИЯ ВЗРЫВООПАСНОЙ КОНЦЕНТРАЦИИ СЖИЖЕННЫХ УГЛЕВОДОРОДНЫХ ГАЗОВ ПРИ СЛИВЕ/НАЛИВЕ АЦ

During the operation of the multi-fuel auto filling station, there are risks associated with the explosion and fire hazard of the facility, namely the transportation and shipment of explosive liquefied petroleum gas, with the depressurization of which it is possible to spread LPG vapors through the territory of the multi-fuel filling station, which can lead to ignition of LPG vapors and subsequent detonation. The issue of the safety of multi-fuel filling station (auto gas filling station) is relevant today. The regulatory document NPB-111-98 specifies the mandatory requirement for the already built the multi-fuel filling station. To meet the fire safety requirements for the multi-fuel filling station, an installation has been developed to prevent the formation of an explosive concentration of liquefied petroleum gases during the discharge/filling of the tanker truck. The installation for preventing the formation of an explosive concentration of LPG at the tanker truck shipment site is a system of supply and exhaust ventilation placed in such a way that on the one side of the edge the air flow creates a backstop with air inflow, on the other side a vacuum is created by the exhaust system. For the selection of equipment, the calculation of ventilation ducts, air flow velocity and system resistance was performed. The requirements for the mobility of the vapor phase on the surface have been achieved, which is at least 2 m/s. The project was implemented at a number of the multi-fuel auto filling station of a large oil company.

Gigantic stimulation in response by solar irradiation in self-healable and self-powered LPG sensor based on triboelectric nanogenerator: Experimental and DFT computational study

The present paper reports the highest sensor response of Solar light induced, battery-less and self-healable LPG sensor powered by triboelectric nanogenerator. This work establishes the concept of waste to energy conversion and utilization of waste energy (finger tapping) for driving sensors for green and sustainable development. In this study synthesis of 2D PANI-PPY (2P) nanosheets by the polymerization and further its employment as PDMS/PANI-PPY (3P) based TENG is demonstrated. The fabricated TENG exhibits high output voltage of 142 volts and 80 µA current. 3P polymer nano-composite showed fast self-healing capability under 35 min. The assembled 3P based self-powered LPG sensor exhibits exceptional response and sensitivity under light illumination. The maximum sensor response of 94.67 (% response = 9367%) and the sensitivity 52.67 SR/vol% were found under 30 mW/cm2 visible light radiance, which illustrates that the developed material is extremely responsive and sensitive under light condition even at a very low concentration of LPG below LEL (2 vol%). The least recovery and response times of the material were measured to be 172 ms and 580 ms correspondingly. The theoretical analysis confirms that Cl-doped 2P was highly reactive and exhibited high negative potential sites to interact with the H+ ion of LPG.

Sensing mechanism of PbO doped tin oxide thick film for detection of LPG

The present work studied PbO doped tin oxide (SnO2) based thick films using screen printing technique. We fabricated undoped and PbO-doped SnO2 thick film on an alumina substrate to be used as a sensor. There are three samples are prepared in the laboratory as S1 (SnO2 thick film), S2 (1 wt% PbO at firing temperature 800 °C), and S3 (1 wt% PbO at firing temperature 900 °C). The microstructural properties are observed using XRD data. XRD measurement reveals that the crystallite size in nanometric rage and it is ∼31.51 nm, 27.09 nm and 22.90 nm for S1, S2, and S3 respectively. The sensing performances of fabricated thick films are investigated at an operating temperature of 200 °C upon exposure to LPG concentration in the range of 0–5000 ppm. It is found that the maximum response of LPG at an operating temperature of 200 °C (5000 ppm) is 26 % and 20 % for S3 and S2 respectively. The response of sensor S3 is ∼2 times more sensitive to S1 and ∼1.47 time sensitive to S2 for LPG. Therefore the fabricated PbO–SnO2 sensor may use for appropriate detection of LPG and also observed the experimental result of the sensor are in good agreement with the predicted theoretical model.

Numerical Description of Jet and Duct Ventilation in Underground Garage after LPG Dispersion

Contamination of toxic and odorous gases emitted from stacks in buildings located in an urban environment are potential health hazards to citizens. A simulation using the computational fluid dynamic technique may provide detailed data on the flammable region and spatial dispersion of released gases. Concentrations or emissions associated with garage sources and garage-to-house migration rates are needed to estimate potential exposures and risk levels. Therefore, the aim of the study was to use an original mathematical model to predict the most accurate locations for LPG sensors in an underground garage for vehicles powered with LPG. First, the three-dimensional geometry of an underground garage under a multi-family building was reconstructed. Next, two types of ventilation, jet and duct, were considered, and different sources of LPG leakage were assumed. Then, the Ansys Fluent software was applied as a solver, and the same initial value of released LPG (5 kg) was assumed. As a simplification, and to avoid the simulation of choked outflow, the emission from a large area was adopted. The results showed stagnation areas for duct ventilation in which gas remained for both the jet and duct ventilation. Moreover, it was observed that the analyzed gas would gather in the depressions of the ground in the underground garage, for example in drain grates, which may create a hazardous zone for the users of the facility. Additionally, it was observed that for jet ventilation, turbulence appearance sometimes generated differentiated gas in an undesirable direction. The simulation also showed that for blowing ventilation around the garage, and for higher LPG leakage, a higher cloud of gas that increased probability of ignition and LPG explosion was formed. Meanwhile, for jet ventilation, a very low concentration of LPG in the garage was noticed. After 35 s, LPG concentration was lower than the upper explosive limit. Therefore, during the LPG leakage in an underground garage, jet ventilation was more efficient in decreasing LPG gas to the non-explosive values.

GRAPHICAL METHOD FOR DETERMINATION OF MQ-SERIES GAS SENSOR CIRCUIT PARAMETERS FOR A STAND-ALONE GAS ALARM SYSTEM

Background: MQ-series gas sensors belong to the metal oxide semiconductor (MOS) family of sensors that can sense the presence of many gases. These sensors find their application in gas alarm systems as key components. While necessary sensor circuit output voltage value for alarm point in a stand-alone gas alarm system is desirable, but what exact combination of the sensor circuit parameters is required? Hitherto, the determination of these circuit parameters has not been given much attention in the research community. Aim: the purpose of this work is to explore a structured graphical approach of determination of MQ series gas sensor circuit parameters for a stand-alone gas alarm system that yields desired sensor circuit output voltage value for the alarm point; the main objective of the study was to develop mathematical model equations that relate the: (i) sensor resistance (RS) with the gas concentration (x) and the sensor resistance at standard calibration concentration of the sensor base gas in the clean air (Ro) and (ii) sensor circuit output voltage (VRL), load resistance (RL) and sensor resistance (RS). It is expected from the model equations developed that graphical correlations of the sensor circuits parameters will be generated. Using these graphs for a particular case of an MQ-4 gas sensor under the influence of LPG, the parameters that yield desired sensor circuit output voltage of 2V for 1000 ppm of LPG alarm point will be determined. Methods: Model equations were developed for the sensor dynamics, and based on these model equations, graphs for the determination of required sensor parameters were plotted for a case of MQ-4 gas sensor response to LPG. Results and Discussion: The results yielded optimal values for R_O,R_S and R_L of 20 kΩ, 30 kΩ and 20 kΩ respectively, for alarm settings of 1000 ppm and a desired sensor circuit output voltage of 2 V. Based on determined parameters, the calibration equation for determination of best concentration value for a given value of emulated LPG concentration was developed. Using the method proposed in this study makes the process of determining the MQ-series gas sensor circuit parameters less cumbersome as their value can easily be obtained from the resulting graphs. Conclusions: a structured graphical approach for determination of MQ-series gas sensor circuit parameters for alarm points in a stand-alone gas alarm system showed that using MQ-4 gas sensor and LPG as the target gas, and for a sensor circuit output voltage of 2 V for alarm point at 1000 ppm of LPG, the corresponding value of R_O, R_S and R_L obtained were 20 kΩ, 30 kΩ, and 20 kΩ respectively. Hence, a structured graphical approach is suitable for determining MQ series gas sensor circuit parameters for a stand-alone gas alarm system under the influence of its associated gases.

State of the Art Implementation of Automated Fire Accident Detection with Robust Control by Utilizing Industry 4.0 Terminology

The key work of this research is to implement the ‘Fourth Industrial Revolution’ by using the internet of things (IoT) which can be applied to flammable gas condition monitoring and detection of gas leakage and activate fire extinguisher in case of fire accidents. Internet of things enabled the sensors to transmit LPG concentration value reading to the mobile app or cloud server and control actuators by connecting all in the same network. In case of a fire accident, the solenoid valve will be opened automatically or can be opened by an android application manually which will be pre-installed in mobile phones. Another advantage of this system is, the gas cylinder or flammable particle source can be closed by closing the solenoid valves attached to their outlets. The first challenge of industry 4.0 is to develop a cyber-physical system where all physical entities can be monitored and controlled over the internet or another way remotely or from a single point. This fire extinguisher system can be used everywhere and in all types of fire-fighting because all types of fire extinguishers are commercially available in cylinders where solenoid valves can be used instead of conventional valves. Use of robust automatic control system will eliminate the effort of human for continuous monitoring of LPG condition, leakage and in the activation of fire extinguishers by cyber-physical system.

Design and fabrication of quick responsive and highly sensitive LPG sensor using ZnO/SnO2 heterostructured film

Highly efficient LPG sensor working at room temperature was developed using a simple and cost-effective route. For this purpose, ZnO/SnO2 heterostructure was synthesized using the hydrothermal route and thin films of the material were prepared. X-ray Diffraction revealed all the crystal parameters including grain size, texture coefficient, dislocation densities, surface area which are necessary for a sensor. Also, particle size, zeta potential, and conductivity were observed using nanozetasizer. Heterojunctions at the surface of the film were viewed by Scanning electron microscopy. An optical band-gap of ∼3.85 eV was measured using UV–vis absorption spectrum. Further, the film was used as room ambient sensor for different concentrations of LPG. Among them, the best sensor response and sensitivity of 276.51 and 3.78 respectively were obtained for 2.0 vol% of LPG whereas minimum response and recovery time of 10 s and 15 s were obtained for 0.5 vol% of LPG.

Spray Analysis and Combustion Assessment of Diesel-LPG Fuel Blends in Compression Ignition Engine

A major challenge for internal combustion engines (ICEs), and diesel engines, in particular, is the reduction of exhaust emissions, essentially nitrogen oxides (NOx) and particulate matter (PM). In this regard, the potential of LPG-diesel blends was evaluated in this work. The LPG and diesel blends were externally prepared by exploiting their perfect miscibility at high pressures. Two diesel-LPG mixtures with 20% and 35% by mass LPG concentrations were tested. In terms of spatial and temporal evolution, the spray characterization was performed for the two blends and pure diesel fuel through high-speed imaging technique. The combustion behavior, engine performance and exhaust emissions of LPG-diesel blends were evaluated through a test campaign carried out on a single-cylinder diesel engine. Diesel/LPG sprays penetrate less than pure diesel. This behavior results from a lower momentum, surface tension and viscosity, of the blend jets in comparison to diesel which guarantee greater atomization. The addition of LPG to diesel tends to proportionally increase the spray cone angle, due to the stronger turbulent flow interaction caused by, the lower density and low flash-boiling point. Because of improved atomization and mixing during the injection phase, the blends have shown great potential in reducing PM emissions, without affecting engine performance (CO2 emissions). The addition of LPG resulted in a significant smoke reduction (about 95%) with similar NOx emissions and acceptable THC and CO emissions. Furthermore, the low cetane number (CN) and high low-heating value (LHV) ensuring leaner air-fuel mixture, and improvements in terms of efficiency, particularly for a blend with a higher concentration of LPG.

Healable, highly sensitive LPG sensor based on Ni0.4Zn0.6Fe2O4 nanohybrid grown by autocombustion process

In this study, dual-layered self-healable LPG sensor which can successfully re-establish both of its structural and sensing properties after an external deformation occurred, has been reported. Here Ni0.4Zn0.6Fe2O4 (NZF) works as a highly sensitive LPG sensor which can detect LPG well below the lowest explosion limit (LEL) efficiently. The self-healing phenomenon has been achieved by urea-formaldehyde (U-F) microcapsules encapsulating NZF and linseed oil. The dual-layered self-healable sensing film is prepared by forming a lower layer using urea-formaldehyde (U-F) microcapsules capturing linseed oil and NZF, serving as healing layer, and an upper layer using NZF aiding sensing phenomenon. LPG sensing parameters like sensitivity, sensor response, recovery time and response time were investigated in case of both uncracked sample and healed sample to get a clear idea of how much sensing properties were recovered after healing took place. The minimum response and recovery times of the uncracked film corresponding to 0.5 vol.% LPG concentrations were found to be 28.08 s and 52.46 s respectively, whereas, the same after healing were as 34.39 s and 45.17 s respectively. After healing, ∼ 86.4 % sensitivity was restored. This is the first dual-layered microcapsule-based LPG sensor, which has healing property.

Sensing and structural characteristics of TiO2 thick film for LPG sensor

The sensing behavior and structural properties of cadmium sulfide (CdS) doped titanium dioxide (TiO2) thick film gas sensor were investigated and grown onto the alumina substrate. Microstructural properties are studied using X-Ray diffraction (XRD). The XRD measurement reveals that, the crystallites size of TiO2 was found ∼25.6 nm and ∼22.6 nm for sensor T1 (undoped TiO2) and T2 (CdS-TiO2) respectively. The response of the fabricated sensor T1 and T2 is measured varying the concentration of LPG (0–5000 ppm) in air ambient at 300 K. We observed that the sensor T2 has the highest response toward LPG (35) which is 2.5 times more than sensor S1 for the concentration of LPG (5000 ppm). The transient times of the fabricated sensor T2 are 130 sec and 350 sec.

Air Quality Monitoring Device for Vehicular Ad Hoc Networks: EnvioDev

Urban air pollution has become a major concern for numerous densely populated cities globally since poor air quality may cause various health problems. The first crucial step towards solving this important problem is to identify the most critical areas with the highest air pollution over the allowed limit. Nowadays, air pollution is monitored by various stationary measurement systems that are expensive, large, consume a big amount of energy and gathered data has a low spatial resolution. This paper presents EnvioDev, a mobile air quality and traffic conditions measurement device for Vehicular Ad hoc Networks (VANETs) that can be used on any type of a vehicle. EnvioDev was tested in a real-world urban environment measuring CO, CH4 and LPG concentrations, as well as air temperature and humidity in order to create a city pollution map and the results are presented in the paper. Moreover, in order to determine how many EnvioDev devices are required to obtain close to a real-time air quality map of an urban area, three experiments with Simulation of Urban Mobility (SUMO) simulator were conducted. In the experiments an urban city map was divided into five zones and data aggregation frequencies are varied during different traffic load periods in order to study the number of required vehicles with EnvioDev measurement device. The obtained results show that by increasing the data aggregation frequency the number of required vehicles with EnvioDev measurement device increases and it is depended on the size and topology of the testing area.

Synthesis and structural investigations of microporous graphene-reinforced h-BN solids for LPG sensing applications

Graphene attracts much attention due to its unique thermal, optical, and electrical properties. Two-dimensional (2D) graphene has outstanding electrical and thermal properties such as high charge mobility, ballistic transport and high thermal conductivity. However, the 2D hexagonal boron nitride (h-BN) contains parallel lattice configuration to graphene, this has a lattice difference with graphene of less than 1.7%. Herein, two different composite samples of h-BN reinforced graphene nanoplatelets (GNPs) via scalable conventional solid-state reaction method were synthesized. The x-ray diffraction (XRD), Fourier transforms infrared (FTIR) and Raman spectroscopic analysis revealed the formation of a highly crystalline and layered product. Scanning electron microscope (SEM) results reveals the uniform distribution of fully developed interconnected mixed nanosheets of GNPs and h-BN. The sensing results exhibited that the average sensitivity of the sensor increases linearly with increasing the concentration of LPG. The complex heterostructures formation of GNPs reinforced h-BN displayed its unique sensing properties; which enables to have a broad prospect for the fabrication of sensing devices.

Fabrication of coplanar microheater platform for LPG sensing applications

The design and fabrication of nichrome based coplanar microheater for LPG sensing applications is presented in this work. Nichrome based coplanar microheater is fabricated using photolithography process. The surface morphology of DC sputtered nichrome is characterized using scanning electron microscope. Electrothermal behaviour of the fabricated microheater is characterized by varying the applied current while the thermal distribution pattern over the active heating area is recorded using thermal imaging camera. The silicon thickness under microheater active area is varied by silicon etching with different time duration in TMAH solution. Silicon thickness effect on maximum temperature of microheater is also investigated experimentally. The tin oxide (SnO2) thin film as LPG sensor is deposited on fabricated coplanar heating platform and it is tested with different amount of LPG concentration.

Humidity and selective oxygen detection by Ag2S nanoparticles gas sensor

We report selective oxygen detection by Ag2S nanoparticles gas and humidity sensor at low temperatures with high sensitivity. The Ag2S nanoparticles with preferentially oriented plane (−112) and texture coefficient ~ 1.49 were synthesized by co-precipitation technique. The bandgap and surface area of Ag2S nanoparticles was 2.03 eV and 16.30 m2/g respectively. The response of Ag2S nanoparticles to detect different concentrations of oxygen, LPG, methanol, ethanol and 1-butanol at different temperatures (24–160 °C) was investigated. The Ag2S nanoparticles exhibited a linear relationship between response versus concentration at different temperatures for the tested gases. However, the Ag2S nanoparticles exhibited high response, shortest response/recovery time, good stability and recyclability to oxygen as compared to other tested gases at 160 °C. At room temperature the response of the Ag2S nanoparticles relative humidity (RH) sensor increased linearly with increase in RH. Ag2S nanoparticles as RH sensors also exhibited high response, short response/recovery time, good stability and recyclability.

Sol–Gel Spin-Coating Followed by Solvothermal Synthesis of Nanorods-Based ZnO Thin Films: Microstructural, Optical, and Gas Sensing Properties

Zinc oxide thin films with nanorod morphology were investigated for microstructural and optical properties as well as their performance as a liquid petroleum gas sensing material. A two-step synthesis procedure consisting of sol–gel spin-coating and solvothermal methods was employed where several factors such as rational utilization of metal precursors, solvent, stabilizing, and structure directing agents, a repetitive drying-coating process, as well as post-thermal annealing were found influential to obtain qualified nanorods and a final homogeneous thin film. Compositional and optical investigations were pursued to characterize features, namely morphology, poly crystallinity, porous structure, nanocrystallite size, lattice oriented growth, textural atomic ratio, lattice purity and transparency, phonon and exciton transitions, as well as the formed structural defects via field-emission scanning electron microscopy, x-ray diffraction, energy-dispersive x-ray, UV–Vis spectroscopy, Raman, and photoluminescence techniques. The as-prepared thin film was then used as an active LPG sensing material via a home-made gas sensor where the control sensing parameters were chamber testing temperature and gas concentration. Results showed a quantitative response of 92.7% as sensor sensitivity at an operation temperature of 250°C and a LPG concentration of 800 ppm in addition to fast response and recovery times of 44.1 s and 218.7 s, respectively.

Tin (II) Oxide Nanostructure Thin Film by Thermal Oxidation Technique as LPG Sensor

Tin (II) oxide based nanostructure thin films were synthesized using thermal oxidation of pure tin metal on glass substrates. To investigate the effect of thermal oxidation temperature and time on LPG sensing performance of thin films, it was carried at various oxidation temperatures 500, 600, 700, 800, 900 and 1000 °C with oxidation time of 30, 60, 90, 120, 160 and 190 s respectively. These sensors were tested for 100 ppm concentration of LPG. Thin films synthesized at oxidation temperature of 800 °C and oxidation time of 120 s exhibit highest response (% Sf = 5 x 103) at operating temperature of 120 °C. The sensors were found to be extremely stable and repeatable with a response and recovery time of 29 and 84 s.<div><br></div>

Fast-LPG Sensors at Room Temperature by α-Fe2O3/CNT Nanocomposite Thin Films

We present performance of a room temperature LPG sensor based on α-Fe2O3/CNT (carbon nanotube) nanocomposite films. The nanocomposite film was fabricated via the metallic Fe catalyst particle on CNTs in which both the catalyst particles and the CNT were simultaneously synthesized by chemical vapor deposition (CVD) synthesis and were subsequently annealed in air to create α-Fe2O3. These methods are simple, inexpensive, and suitable for large-scale production. The structure, surface morphologies, and LPG response of nanocomposite films were investigated. Raman spectroscopy and XPS analysis showed the formation of α-Fe2O3 on small CNTs (SWNTs). Morphological analysis using FE-SEM and AFM revealed the formation of the porous surface along with roughness surface. Additionally, the sensing performance of α-Fe2O3/CNTs showed that it could detect LPG concentration at lower value than 25% of LEL with response/recovery time of less than 30 seconds at room temperature. These results suggest that the α-Fe2O3/CNTs films are challenging materials for monitoring LPG operating at room temperature.

Nanostructured ZnO films for potential use in LPG gas sensors

The aim of the work was to obtain ZnO nanostructures with heightened surface area and to study relationship between formation method and gas sensor properties towards propane-butane mixture (LPG). In order to synthesize ZnO nanostructures chemical and physical formation methods have been utilized. The first one was chemical bath deposition technology and the second one magnetron sputtering of Zn followed by oxidation. Optimal method and technological parameters corresponding to formation of material with the highest sensor response have been determined experimentally. Dynamical gas sensor response at different temperature values and dependencies of the sensor sensitivity on the temperature at different LPG concentrations in air have been investigated. It has been found, that sensor response depends on the sample morphology and has the highest value for the structure consisting of thin nanowires. The factors that lead to the decrease in the gas sensor operating temperature have been determined.