Portable Micro Research Articles

State space modelling development of Micro-High-Temperature Gas-Cooled reactor with helium Brayton cycle

The micro-high-temperature gas-cooled reactor with helium Brayton cycle (Mi-HTR) can be used as a portable micro mobile nuclear power supply. The nonlinear model based on differential equation makes it difficult to reveal the relationship between the internal state of Mi-HTR and the external input and output variables. Based on the operating principles, laws, and theorems, the nonlinear dynamic model between various parameters and external effects in the system is established. According to the nonlinear dynamic model, the state space model of Mi-HTR is obtained by theoretical derivation. The established state space model can describe the relationship between internal intermediate variables. The disturbances with the same boundary conditions are introduced into nonlinear dynamic model and state space model respectively. The accuracy of the established Mi-HTR state space model is proved. The Mi-HTR state space model provides an analytical tool for the design of Mi-HTR control system.

Recent advances on portable photoelectrochemical biosensors for diagnostics

AbstractEfficient and accurate diagnostic methods are important for human health monitoring and prevention of major diseases, so the establishment of efficient and convenient testing methods for clinical diagnosis is urgent. Photoelectrochemical (PEC) biosensors have attracted much attention because of their high sensitivity, low detection background, and especially the advantages of combining photoexcitation and electrochemical detection. With the rapid development of integrated circuit technology many wireless transmissions of highly aggregated portable micro devices are manufactured, its small size, easy to carry, and the ability to visualize the results of the test is shown to be the potential for the application of such devices. This review aims to cover recent advances in PEC biosensing within the field of portable detection, including the principles of PEC biosensors, common photovoltaic materials, and scalable fabrication techniques for portable PEC biosensing. Future prospects in the field are also discussed.

Performance Comparison of Paper‐ and Cotton‐Based Al‐Air Batteries without Catalysts for Low‐Cost Portable Micro Devices

AbstractConventional Al‐air batteries are not suitable as portable power devices due to their complicated water management and bulky system. To resolve this issue, the fiber paper‐ and cotton cloth‐based Al‐air batteries were proposed, which exploited the capillary force from the paper (FP) and cotton cloth (CC) to deliver the solutions and eliminated the external pump. The physical features of the FP and CC were gained including the surface morphologies, surface elementary analysis, liquid absorption and flow rates. CC owned larger liquid absorption and faster flow rate due to its hierarchically woven‐spun fiber structure, compared to the randomly oriented fibers of the FP, although the surface of the CC demonstrated lower O/C ratio than that of the FP. So, the performance of the CC‐based Al‐air battery was largely higher than that of the FP‐based battery. The performance of the CC‐based Al‐air battery was optimal at 1.0 M NaOH electrolyte and the anode‐to‐cathode surface area ratio of 1 : 4, with the peak power density of 14.95±0.28 mW cm−2, and the maximum current density of 36.61±0.54 mA cm−2. To apply the CC‐based Al‐air battery, the two‐battery pack connected in series was assembled to drive a timer and light 9 LEDs.

Output power regulation system for portable micro fuel cell systems

This article presents an output power regulation system for micro fuel cells to help enhance the stability of the fuel cell in a portable micro power system. The structure of an MCU-controlled DC-DC converter is proposed. Then, the output characteristics of a selected fuel cell stack and the DC-DC converter’s power control functions are estimated by a system-level model. Based on the simulation results, the model provides a power regulation system which is implemented, and the test shows that it fulfills its intended function and the output power is regulated to a fixed level of 5 W–40 W with good efficiency.

A Review on Electrospun PVDF-Metal Nanoparticle Composites for Electronic Applications

In this review, we have discussed on the latest development in metal nanoparticle composites based on PVDF via electrospinning process for electronic applications. Human robotics, wireless-data communication, nanogenerators, wearable biocompatible/bio-inspirable sensors, motion detectors, and actuators have become a key component in self-powered IoT devices. Due to the power demand, an urge is in the industry for fabricating portable, flexible, and sustainable green micro and nano devices. PVDF and its copolymers have attracted greater attention because of their excellent piezoelectric, dielectric, magnetic, and good mechanical properties, suitable for lightweight application and due to the biocompatible nature. Piezoelectric property can be enhanced with the addition of different metal nanoparticles and can be used for various application like sensor, actuators, energy harvesters, health monitors, EMI shielding. Interesting results reported by many research groups working in this field is consolidated in this review paper.

Perancangan Alat Micro Hydroelectric Portable dengan Menggunakan Sistem Turbin Archimedes Screw

Micro Hydroelectric portable is a small-scale hydroelectric power plant (< 100 kW) which has many advantages, especially without the use of reservoirs, is environmentally friendly, and is a renewable energy, so many are built for power generation purposes in rural areas. Micro Hydro is generally a permanent generator, so the main problem faced is the relatively expensive construction cost. The prototype of a Portable Micro Hydro Power Plant using an Archimedes screw turbine is a power plant that is capable of working on small-scale water discharge in the form of a beam with a length of 80 cm, a width of 40 cm, a turbine housing slope of 45o and a total weight of 8 Kg, making it a portable Micro Hydro. Micro Hydro works at a water flow rate of 0.1 - 1.1 m3/second using an Archimedes screw turbine which can work at low heads. Power from the Archimedes screw turbine is channeled to the generator using a 1:3 ratio, where one rotation of the turbine produces three rotations of the generator producing an average voltage of 7.3 Volts DC, then the voltage is converted by the inverter, charger controller, battery for 12 Volt loads, 12 Watt generated power capacity

Mechanism study and evaluation of high efficiency paper-based microfluidic fuel cell coupled with capillary force

Under the dual pressure of energy consumption and environmental pollution, mankind hopes to develop clean and renewable alternative energy, and the rapid development of fuel cells meets people's demand for energy-efficient power systems. The emergence of portable micro energy systems represented by microfluidic fuel cells, such as paper-based microfluidic fuel cells, has greatly enriched the means of medical detection to better cope with the threat of disease transmission. In this work, the numerical simulation method is innovatively introduced to study the paper-based microfluidic fuel cells. Both transient and steady-state modes are employed to demonstrate the whole operation process of the paper-based microfluidic fuel cell. In addition, the different structural parameters, including electrode spacing, the distance between electrode and inlet, channel thickness, and electrode length, are also investigated their influence mechanisms on cell performance. Results show that the increase of most structural parameters decreases cell output power in different degrees. Even on the premise that increasing channel thickness has a positive impact on the output power, the fuel utilization still shows a downward trend. These conclusions provide theoretical support and reference for future optimization work and accelerate the development of microfluidic fuel cells.

Physicochemical characterization and heavy metals analysis from industrial discharges in Upper Awash River Basin, Ethiopia

The recent expansion of industries in Addis Ababa is causing additional environmental pollution through wastewater discharges; this is becoming a critical concern. Addis Ababa is located in the upper Awash River basin, and is the main source of industrial pollutants to the river. In this study, physicochemical parameters, nutrients and heavy metal content of wastewaters released from 16 factories, 6 tanneries, 6 beverages and 4 diverse factories, and the Akaki-Kality central wastewater treatment plant in Addis Ababa, were sampled to assess the level of pollutants. Heavy metals were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Analysis of nutrients were conducted using Palintest Photometer. Physicochemical characteristics were measured either in situ using a portable micro meter or in the laboratory. Among the measured physicochemical properties, critical issues were observed with electrical conductivity, total dissolved solids and total hardness. Effluents from all of the tanneries, and a number of other factories, were found at levels higher than the maximum limits of various guideline standards. In addition, samples from two of the tanneries (T1 and T5), two beverage factories (B3 and B6) and the central wastewater treatment plant showed elevated concentrations of PO4 3-, which violated the limit (10mg/l) set by Environmental Protection Agency of Ethiopia (ETHEPA). The two tanneries (T1 and T5) also contained higher SO4 2- than the guideline limit of 1000mg/l. On the other hand, only one factory, one brewery (B3), exhibited NO3 - above the standard limit of 20mg/l. Whereas NH3, NH4 +, Cl-, S2- and NO2 - were within the limits in all of the samples. Severe pollution was found in wastewaters from tanneries, where half of them (T1, T5 and T6) contained Cr beyond the maximum limit of 2000µg/l. Furthermore, a third of the tanneries (T1 and T5) and a beverage factory (B5) contained Fe, Mn, Zn and Cu, higher than the ETHEPA limits of 10000, 5000, 5000 and 2000µg/l, respectively. Waste disposal from factories without proper treatment can cause great harm to the local people and the environment. Hence, the results of this study call for regulatory bodies to pay close attention to factories, particularly tanneries, in Addis Ababa in implementing adequate treatments of their wastewater discharges.

Recombinant human vascular endostatin injection to synchronize craniospinal radiotherapy for the treatment of recurrent medulloblastoma in children: A retrospective clinical study*

Abstract Objective Medulloblastoma (MB) is the most common primary central nervous system malignancy in children. Nonetheless, there is no standard treatment for recurrent MB. The purpose of this study was to investigate the clinical value and toxicity of recombinant human endostatin injection (Endostar®) combined with craniospinal radiotherapy for the treatment of recurrent MB in children. Methods This study retrospectively analyzed 13 patients with recurrent MB aged 5-18 years. Endostar® 7.5 mg/m2/d was synchronized during craniospinal radiotherapy for 7 children with a portable micro uniform speed infusion pump. Endostar® was applied 3 days prior to the initiation of radiotherapy. The drug was in continuous use for 7 days. Similarly, the withdrawal of the drug took place over 7 days. This represented a cycle. During radiotherapy, the application was repeated until the end of radiotherapy (experimental group). In the other 6 cases, only craniospinal radiotherapy was used (control group). Results The complete remission rate was 71.4% in the experimental group and 16.7% in the control group. The median progression-free survival (PFS) was 14 months (95% CI: 0.0-29.60) and 19 months (95% CI: 0.0-39.53) in the experimental and control groups, respectively. The median overall survival (OS) was 19 months (95% CI: 0.0-38.20) and 23 months (95% CI: 2.47-43.53) in the experimental and control groups, respectively. The most common adverse events included grade 1 thrombocytopenia (7.7%), grade 3 neutropenia (38.5%), and grade 1 anemia (30.8%). Conclusion Endostar® synchronizing craniospinal radiotherapy significantly improved the complete response rate of children with recurrent MB. It did not increase the side effects of radiation therapy. However, it did not improve the PFS or OS.

Bronze votive pins from the sanctuary of Athena Alea at Tegea, Arcadia, Greece, ca. 9th-7th BCE: A microscopic and compositional study using portable micro X-ray fluorescence spectrometry (micro-XRF)

We examined an assemblage of 72 copper alloy pins from the Athena Alea sanctuary at Tegea in central Peloponnese, Greece, dated to the 9th-7th centuries BCE, with a stereo-microscope and with micro X-ray fluorescence spectrometry. The microscopic and elemental analyses investigated the technology and metalworking practices used in the sanctuary’s votives with a micro-invasive analytical protocol. Results confirmed that the assemblage consists of copper-tin binary alloys and provide evidence for the continuity of bronze in the Tegea area during the Geometric (9th-7th century BCE) and Orientalising (7th century BCE) periods. Most of the artefacts are made of bronze with an average tin content of ca. 9 wt% Sn, while a small group (n= 3) of pins is tin-free (<0.3 wt% Sn). Tin concentrations in the alloys do not correlate with the typology of the pins. The results further suggest an intentional addition of tin, as indicated by the normal distribution of tin values, along with a local metallurgical technology, that catered for the local sanctuary’s demand for votive objects.

First insights into the archaeometric analysis of the Los Amores Mosaic in C\xe1stulo (Linares, Spain): the Judgement of Paris

This paper discusses results obtained from in situ analysis of the tesserae of the Roman mosaic of Los Amores (Cástulo site, Linares, Spain) dating back to the turn of the 1st to the 2nd century AD. Specifically, it focuses on the scene The Judgment of Paris. In view of the exceptional state of preservation of the mosaic, from which very few tesserae had fallen off, non-invasive methods with portable Micro Raman Spectroscopy (MRS) and hand-held X-ray fluorescence (hXRF) and data assessment by use of principal component analysis and binary representations were selected. The results obtained allow to evaluate both the analytical method and the portable equipment used, as well as to classify the raw materials, the colouring agents and the opacifiers used. MRS analysis proved crucial for the identification of stone tesserae (ironstones, carbonate and siliciclastic rocks) and for the identification of the type of glasses used (soda-lime-silicate and lead type glasses) based on the analysis of two detached tesserae. hXRF analysis of the glass tesserae identified both colouring agents (Co, Cu, Pb, Zn) and opacifiers (calcium antimonate). The data obtained lend themselves to an assessment of the degradation process that threaten the integrity of the mosaic. The identification of tessera made of specific stone materials (especially ironstone) and of lead glass tesserae suggest the existence of a mosaic workshop in the Upper Guadalquivir (Eastern Andalusia, Spain).

Analysis of Robusta coffee cultivated in agroforestry systems (AFS) by ESI-FT-ICR MS and portable NIR associated with sensory analysis

Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI(±)FT-ICR MS) and portable micro near-infrared spectroscopy (microNIR), coupled to sensory analysis, were used to propose a new analytical methodology to observe the characteristics of Robusta coffees cultivated in agroforestry systems (AFS). Principal component analysis (PCA) chemometric models provided excellent discrimination of the samples analyzed by ESI(±)FT-ICR mass spectra for the ground coffee grains. Analysis of the spectra allowed for identification of the compounds responsible for distinguishing the samples grown with different intercropping AFS species. The microNIR results corroborated the ESI(-)FT-ICR MS data and the sensory analysis, by grouping together coffees grown in AFS intercropped with Gliricidia sepium and Inga edulis. The coupling of these analytical techniques shows promise in coffee quality control, presenting advantages such as collection at point analysis, speed, and analytical reliability.

Karakteristik Emisi CO2 Tanah Gambut di Bawah Tegakan Kelapa Sawit

Penelitian ini bertujuan mengkaji karakteristik emisi CO2 dari tanah gambut di bawah tegakan kelapa sawit yang dihubungkan dengan faktor lingkungan spesifik lokasi penelitian di daerah Kabupaten Labuhan Batu, Sumatera Utara. Gas CO2 diambil dengan menggunakan close chamber technique, sedangkan konsentrasi gas tersebut diukur menggunakan portable micro Gas Chromatograph CP 4900. Faktor lingkungan sebagai variabel bebas yang diamati meliputi suhu tanah (TS), suhu atmosfer (TA), kelembaban tanah lapisan 0 – 5 cm (SM5), kelembaban tanah lapisan 0 – 30 cm (SM30), dan pH gambut (A). Model hubungan CO2 dengan faktor dianalisis menggunakan analisis korelasi Spearman dan regresi multivariant. Analisis regresi multivariant dilakukan menggunakan regresi stepwise untuk mengetahui faktor lingkungan yang mempunyai hubungan dengan CO2 pada taraf beda nyata 5%. Analisis variance inflation factor (vif) dilakukan untuk melihat multicollinearity dari model regresi multivariant. Berdasarkan analisis korelasi Spearman, faktor lingkungan A (pH gambut) mempunyai koefisiensi korelasi yang tegolong sedang (R = 0.637). Hasil regresi stepwise menunjukkan bahwa emisi CO2 nyata dipengaruhi oleh kelembaban tanah SM30 dan A (n = 216; p &lt; 0.05) dengan nilai vif &lt;3. Regresi multivariant, menghasilkan persamaan terbaik (R2 = 0.420) dimana emisi CO2 = 7.394*A – 0.008*SM30 – 16.659. Secara parsial, penelitian ini juga memperoleh model hubungan emisi CO2 dengan kelembaban tanah gambut, dimana emisi CO2 tertinggi dicapai pada kondisi kelembaban tanah sekitar kapasitas lapang (354 – 376% w w-1) dan menurun dengan meningkatnya kelembaban tanah di atas kadar air kapasitas lapangan. Emisi CO2 tanah gambut mengalami penurunan pada kondisi tanah gambut mengering di bawah zone kadar air kritis, hal ini karena hidrofobisitas tanah gambut meningkat.

RESCUE PROCEDURE EFFECTIVENESS IN TERMS OF RESPIRATORY MUSCLE FATIGUE

Introduction: Diagnosis of sudden cardiac arrest in an injured person and taking quick actions to restore vital functions is a critical point of pre-hospital care, carried out not only by medical personnel in civilian, but also in water rescue conditions. Aim: The purpose of the study is to identify spirometry and cardiopulmonary indices that influence rescue actions at the level of respiratory muscle fatigue, and may have potential impact on the effectiveness and quality of the rescue operation. Material and methods: The study involved 48 male uniformed soldiers with permission to perform water rescue as part of a training programme regarding tactical activities. Spirometry and cardiopulmonary resuscitation tests were performed before and after lifesaving water tests. The quality of respiratory muscle fatigue at rest and in the condition of fatigue was compared. The recording instrument was the portable Micro Loop spirometer and Ambu Defib Trainer W (Wireless). Results: The respiratory parameters that may affect the quality and effectiveness of rescue water tests in the area of speed and intensity are: peak exhaust flow, maximal ventilation index, ventilation volume per minute, ventilation rate and maximal respiratory pressure. Conclusion: The most important spirometric and cardiopulmonary parameters identifying respiratory muscle fatigue level of are: VmV, FEV, FVC, PEF, FEVO FEV3, which total as much as 12.26% of all parameters taken into account, and their improvement may be associated with better rescue performance, both in qualitative and quantitative terms.

Direct measurement method of micro-beam X-ray focus based on array detector

A method for directly measuring the focal spot size and minimum focus position output by micro-beam X-ray is proposed. An experimental device based on portable micro X-ray source and capillary X-ray lens is built, and the experiments are carried out at different distances and under different tube voltages. The measured results are compared with the knife-edge scanning method. The results show: the focal spot size and minimum focus position of X-ray lens are 87μm and 9.798 cm respectively by using an array detector. X-ray array detector can directly measure the size of focal spot and predict the position of the minimum focus. It has the advantages of real-time measurement, available two-dimensional distribution, high cost performance and high efficiency. The device can predict the minimum focus position better, but the measured focal spot size is larger than it measured by knife-edge scanning method due to the influence of the pixel size and energy response of the array detector. The measurement results are related to the size of the pixel unit, measurement threshold and exposure time of an array detector.

Simulating the spatiotemporal distribution of BTEX with an hourly grid-scale model.

Modeling approaches have been utilized to simulate ambient pollutant concentrations, but very limited efforts have been made to estimate volatile organic compounds in the atmosphere. For this reason, an hourly grid-scale simulation model was developed to determine ambient air concentrations of benzene, toluene, ethylbenzene, and xylene (BTEX). BTEX data were collected over a one-year time frame from the database of the Taiwan Environmental Protection Administration's photochemical assessment monitoring stations. Multivariate linear regression models were used along with correlation analysis to simulate hourly grid-scale BTEX concentrations, using criteria pollutants and selected meteorological variables as predictors. The simulation model was validated in the southern Taiwan area via a portable micro gas chromatography system (n=121) with significant correlation (r=0.566**, ** indicated p<0.01). Moreover, the grid-scale model was applied to areas covering about 72% of the population in Taiwan. A geographic information system (GIS) was used to visualize the spatial distribution of BTEX concentrations from the modeling results. This new grid-scale modeling strategy, which incorporated the GIS output of the simulated data, provides a useful alternative tool for personal exposure analysis and health risk assessment of ambient air BTEX.

Integration of Micro Sensors with Mobile Devices for Monitoring Vital Signs of Sleep Apnea Patients

This paper demonstrates a BSN-based portable monitor integrating micro sensors with mobile devices for monitoring and diagnosing obstructive sleep apnea syndrome (OSAS) at home. The system uses a micro hot-film flow sensor to detect respiratory flow, uses tri-axis micro accelerometer to detect body posture and motion intensity, and uses a micro photoelectric sensor to detect oxygen saturation of blood. The real-time vital signs are detected and transmitted wirelessly to a mobile device. The transmitted data are processed and analyzed in the mobile device and can be further transmitted to a remote medical center and physicians through mobile cellular networks or Internet for comprehensively analyzing, assessing, and diagnosing to the diseases.

A type of portable micro-EDXRF spectrometer with laser displacement sensor

A portable micro energy dispersive X-ray fluorescence spectrometer with Laser Displacement Sensor (LDS) is reported in this paper. Due to irregular or curved surface of archaeological object, the distances between the irradiation spot of sample and exit of polycapillary X-ray optics can vary. In this paper, we employed a LDS in our portable micro-X-ray fluorescence spectrometer to control the distances between the irradiation spot on the sample and the exit of polycapillary X-ray optics in order to decrease the errors caused by the irregular or curved surfaces of samples. In order to test this spectrometer, elemental mapping analyses were carried on with and without LDS on an irregular colored glaze of a piece of curved ancient porcelain, the height difference of two parts of ancient porcelain being nearly 5 mm. From the results, it can be concluded that this spectrometer has potential application prospects in measuring irregular or curved surface of samples.

A portable micro glucose sensor based on copper-based nanocomposite structure

A sensor device based on a copper-based nanocomposite structure is achieved and presents excellent sensing performance for glucose.

Design of double curvature radial turbine blades for a micro gas turbine

The paper reports a study on the design of a radial turbine for a portable micro gas turbine engine. A unique design of blades with double curvatures is proposed which demonstrates the considerable advantage in terms of efficiency and power output. The design process largely consists of design, optimization, and analysis of radial turbine closely based on low mass flow rate and high-pressure ratio. The intention of the development is to achieve reductions both in fuel consumption and emissions. The micro gas turbine engine is designed to generate 20 kW net power output. As a 110 mm centrifugal compressor takes 56 kW power in the Brayton cycle, a 113 mm inlet diameter radial turbine is designed to produce 76 kW power. Optimization of the initial turbine geometry is carried out using an inverse design technique to improve the overall turbine stage performance. The original turbine blade meridional frame was used as an input to the optimization. The optimized 3-D blade geometry have a unique double curvature blade sections which is unlikely to be achieved using the conventional design approach. The performance of the optimized geometry has been compared with that of the initial geometry. Computational fluid dynamic and finite element analysis techniques were used for examining the aerodynamic performance and structural integrity respectively. The rotational speed of the turbine was set up to 101,400 RPM. The result of computational dynamic analysis indicates that the optimized geometry provides an approximately 6% increase in total-to-static efficiency on average and 6 kW increase in power output at high expansion ratio as compared to the original design. Stress analysis shows that the maximum stress is lower than the yield strength of the material, which verifies that the turbine design is mechanically viable.