Metal Blade Research Articles

The characteristics of water-in-biodiesel emulsions produced using ultrasonic homogenizer

The characteristics of the emulsified fuel is largely influenced by the production methods of the emulsion. Although, blending by means of mechanical blender is widely used, the efficacy of using direct ultrasonic homogenizer in producing emulsified fuels has not been explored extensively. Mechanical blender uses metal blades to shear and mix the liquids and the produced emulsion quality would depend on the blade design, rotating speed and mixing duration. Hence, the homogeneity of emulsions produced by different blenders is not consistent. On the hand, ultrasonic homogenizer utilized direct ultrasonic force to produce high frequency vibrating waves to disrupt the immiscible liquid layers and mixed the liquids. Consistency and homogeneity of the emulsion produced by any direct ultrasonic homogenizer can be realized by changing the ultrasonic power, frequency and mixing duration. The current work describes the vital characteristics of water-in-biodiesel emulsions (WiBE) produced by direct ultrasonic homogenization and subsequently, ascertaining the optimum emulsion blends that meet the recommended international fuel specifications for a diesel engine. A total of 48 WiBE samples were prepared and their properties were characterized. The variable parameters for the blends are water content varying from 9% to 15%, three surfactant dosages of 5%, 7% and 9%, and hydrophilic-lipophilic balance (HLB) values ranging from 6 to 9. The results showed that the water particles in the emulsion were uniformly distributed within the continuous phase (biodiesel) and the sauter mean diameter (SMD) values of the water particles were generally small at a mean value of 2.25 µm. Emulsions with 7% and 9% surfactant dosages were observed to have lower SMD values for HLB 7 and HLB 8 respectively. 33 out of 48 samples were found to be stable emulsions. Emulsion with 11% water had the lowest mean density. The viscosity of all samples increased as water contents and surfactant dosages increase. Two samples were found to be the optimum WiBEs which are, 11% water content at HLB 7 with 9% surfactant dosage, and 11% water content at HLB 8 with 7% surfactant dosage.

Characterization of Glass/Jute Hybrid Fibre Reinforced Epoxy Composite for Axial Flow Fan Blade

Traditionally axial flow fan blades were manufactured by using metal alloys, but with the increase in blade size the blades grew heavier resulting in more vibrations during its working. It is impossible to manufacture the metallic blades to close tolerances making it uneconomical. Due to this dimensional instability, the metallic impeller fan blades are instead fabricated with glass fiber reinforced plastics (GFRP). To reduce the after effects of GFRP blades on the environment necessitates the partial reinforcement of natural fibre. This paper deals with the characterization of GFRP blade material with partial Jute reinforcements i.e., glass to jute (95:5) weight percentage and estimating the properties like tensile strength, bending strength, shear strength, fracture toughness. The conventional GFRP blade material has 14 layers of glass fibers in various forms. By placing jute layer at various positions in GFRP blade material the mechanical strengths were estimated and compared with conventional one.

Failure Analysis of Blade on Coconut Shell Crusher Machine

Blade mounted on coconut shell crusher machine was frequently having damaged while being operated in making of coconut shell powder at small and medium industries. This took place repeatedly during the operation, therefore blade repairing and replacement has to be done for every 16 hours at the wear rate of 24.28%. A research was carried out to find out the cause of damage to the metal blade material on the coconut shell crusher machine. The scope of this research included the observation on visual examination, dimensions examination, chemical composition, hardness, and metallography. The results of observations and tests showed that blade was broken due to abrasion and deformation during operation. The metal material used for the blade was low carbon steel. Chemical composition of the metal content of the blade were: C (0.103 up to 0.144 %) and Mn (0.657 up to 1.400 %). Hardness value of blade metal materials were 146 up to 148 Hv. Microstructure consisted of ferrite and pearlite. This low carbon steel material is not suitable to be used as a blade on coconut shell crusher machines for producing of coconut shell. Repairing and maintenance of welding coating methods on blades using low carbon electrodes does not give increased significant value of hardness. Blade replacement in coconut shell crusher machines must comply with the requirements of tool steel with suitable heat treatment or the use of low carbon steel with the carburization process.

Numerical investigation of rub-induced composite fan blade vibrations and abradable coating removals

Composite blade vibrations, removal of abradable coating, and blade stress resulting from blade/casing rubs are investigated. Composite fan blade models with different stacking sequences and a metal blade are created and calculated through a three-dimensional finite element method. Centrifugal stiffness, damping of composite structures, B-spline surfaces, and abradable coating are included in the calculations. The results show that the maximum vibration amplitudes of composite blades at different rotational speeds could be affected by stacking sequences. The responses of metal blade are more sensitive to the natural frequencies of the second to the fifth blade modes than those of the composite blades. Abradable coating removals are highly related to blade vibration amplitudes. Considerably more coatings are removed by the metal blade than by the composite blades at the design speed, particularly in the axial direction. Moreover, according to the stress results, the metal blade is more vulnerable to rub-induced vibrations than the composite blades at the design speed. Larger vibration amplitudes in the composite blades do not necessarily lead to lower failure margins because of the complexity of composite structures. The strategy established can be utilized to aid in the initial designs of state-of-the-art composite blades and reduce potential rub-induced problems.

High vacuum equipment for the measurement of the macroscopic dipole moment of polar molecular crystals.

Polar crystals placed into a charged plate capacitor may experience a mechanical torque. Mounting crystals on a spiral spring allows us to measure the momentum and thus the macroscopic dipole moment of a crystal object. To exclude the influence of ambient conditions (air, ions, electrons), experiments are performed in a high vacuum. Following text book knowledge, polar crystals show a surface charge density especially for faces involving the polar crystal axis. For ambient conditions, it is assumed that external charge carriers compensate the surface charge. Here, we present unique equipment by which the dipole moment of crystals can be measured also when the charge carrying parts of a crystal were cut off by two metallic blades. Present measurements for α-resorcinol (mm2) allow us to conclude that (a) as grown polar crystals measured under the high vacuum condition show a macroscopic dipole moment, (b) the weighted dipole moment increases after cutting the main polar faces, and (c) the weighted dipole moment decreased after exposure to ambient air.

Characterization of Vertically Aligned Carbon Nanotube Forests Grown on Stainless Steel Surfaces.

Vertically aligned carbon nanotube (CNT) forests are a particularly interesting class of nanomaterials, because they combine multifunctional properties, such as high energy absorption, compressive strength, recoverability, and super-hydrophobicity with light weight. These characteristics make them suitable for application as coating, protective layers, and antifouling substrates for metallic pipelines and blades. Direct growth of CNT forests on metals offers the possibility of transferring the tunable CNT functionalities directly onto the desired substrates. Here, we focus on characterizing the structure and mechanical properties, as well as wettability and adhesion, of CNT forests grown on different types of stainless steel. We investigate the correlations between composition and morphology of the steel substrates with the micro-structure of the CNTs and reveal how the latter ultimately controls the mechanical and wetting properties of the CNT forest. Additionally, we study the influence of substrate morphology on the adhesion of CNTs to their substrate. We highlight that the same structure-property relationships govern the mechanical performance of CNT forests grown on steels and on Si.

Experimental and numerical analysis on a compact liquid metal blade heat dissipator with twin stage electromagnetic pumps

For cooling system, liquid metal (LM) have attracted many attentions as an excellent coolant. In this study, we propose a superior liquid metal cooling blade dissipator with twin stage electromagnetic pumps (EMPs), whose thinnest dimension was only 4 mm. The coupling model is utilized to solve the distribution of Lorentz force and the field of velocity and temperature simultaneously in the COMSOL multi-physics software, and the validity of numerical model was verified by experimental data. It is demonstrated that the efficiency of twin stage EMPs was obviously higher than that of single stage of EMP at the same input power theoretically. The Nusselt number at the heater is calculated under the different driven current and heating power. It has been found that there was no obvious change for Nusselt number. Also it can be concluded that the superior property of suppressing thermal shock and high performance-cost ratio were presented.

Absorption-transmission-integrated frequency selective structure based on spoof surface plasmon polariton modes

A method of engineering the frequency selective structure with absorption and transmission based on spoof surface plasmon polariton (SSPP) modes is proposed and demonstrated in this paper. High-efficiency transmission can be achieved based on SSPP modes coupling. Due to the electric field enhancement effect of the coupled SSPP on the metallic blade array, high-efficiency absorption can be achieved by the high loss of the FR4 dielectric substrate. To verify this method, the absorption-transmission-integrated frequency selective structure was designed using the metallic trapezoid structure, metallic fishbone structure and FSS. The metallic trapezoid structure can absorb the low frequency electromagnetic (EM) waves and the metallic fishbone structure can absorb the high frequency EM waves. Two absorption bands are respectively in C and Ku bands. The FSS can modulate the passband characteristic of the metallic trapezoid structure and metallic fishbone structure. High-efficiency transmission can be achieved in the middle of two absorption bands. At last, the absorption-transmission-integrated frequency selective structure was fabricated and measured to verify the feasibility of this method. It can be used for the electromagnetic windows of vessels.

Patrimonio histórico militar: digitalización 3D de la espada nazarí atribuida a Ali Atar

<p class="VARNormal"><strong>Extended Abstract:</strong></p><p class="VARNormal">Ali Atar, Warden of Loja and Lord of Zagra, was born around 1393. He was one of the principal military leaders of the Nasrid period and came to join the Grenadine Royal House by marrying his daughter Moraima with Boabdil, the last King of Granada. He died in the battle of Lucena in 1483, where one of the magnificent jineta swords of Andalusí manufacture was snatched, which is now conserved and located in the collection of the Toledo Army Museum (MUSEJE). The MUSEJE collections house important scientific, technical, historical and artistic heritage. The historical military heritage needs for its protection, preservation and valorisation the adaptation of new resources and benefit from the usage of new digital technologies. The physical conservation is no longer enough for a resource as valuable as cultural heritage; it needs to be complemented with a comprehensive digital preservation in all its forms, being essential and necessary for its proper safeguard. The virtual era currently emphasizes its presence in the digital documentation, preservation and dissemination of our cultural heritage. In particular, we have oriented and activated it on the historical military heritage, knowledgeable and narrator of our history, of its treasures, and of their relationship within the society as important representations of social and dynastic status. This paper is centred in the 3D digitisation by means of digital photogrammetry and 3D modelling of a historical military weapon. Aided by photogrammetry and information and communication technologies (ICT), we will achieve precise geometric documentation and 3D models that are geared towards research, education, diffusion and the preservation of heritage as important and unknown as is historical military heritage. Photogrammetry gives us the opportunity to bring to light the Ali Atar’s sword, one of the most relevant artistic manifestations belonging to the Nasri armament (Fig. 1, Table 1). The multi-view close-range photogrammetry is key to virtualise this jewel and also to contribute to the democratisation of the museum through the web dissemination of its content in a personalized way.</p><p class="VARNormal">Materials such as metals and precious stones, and gold techniques present in the Andalusian weapon required a particular photogrammetric data acquisition using a light booth and polarizing filter (Fig. 10), as suggested for the latter by <a href="file:///E:/PC%20Port%C3%A1til%20Poli/Mis%20documentos/VAR/En%20Curso/Revisi%C3%B3n/10028/VAR_In_Press_10028.docx#Guidi_2014">(Guidi, Gonizzi, & Micoli, 2014)</a>. This setup brought a substantial improvement when dealing with highly reflective materials such as the metallic blade of Ali Atar's jineta sword. The use of the polarising filter attenuated the light that affects and reflects in the piece, benefiting both data acquisition and processing to deliver 3D models. We offered some results ready to safeguard, preserve and disseminate the jineta sword as a high-quality 3D model (Fig. 13), with submillimetre precision from which to obtain all the necessary metric deliverables. From the dense point cloud, two meshes were delivered: i) a homogeneous high resolution mesh keeping all the original features for archiving, conservation and research, and ii) a medium resolution mesh for web-based visualisation and dissemination. The aim was to achieve a detailed geometric documentation as well as complete and accurate 3D models (Fig. 29) for web repositories (<a href="https://skfb.ly/ZzzA">https://skfb.ly/ZzzA),</a> orthoimages (Figs. 30 and 31) that allow us to plot from CAD programs all the ornamental and decorative information of the piece (Figs. 32 and 33). In addition, we present some results related to monitoring and evaluation of changes in the state of conservation of the piece (Figs. 34, 35 and 36), extending the survey to preventive conservation studies.</p><p>This research proves the value of geometric documentation techniques for the democratisation of museums. It contributes to improving the research processes, opening a new line of study. From this point we can rebuild the past through the virtuality, being able to mark and confirm historical hypotheses. These techniques offer the chance to give value to relevant and singular pieces in and out of museums. Both heritage and virtual archaeology are fundamental pillars to delve into the future of education and knowledge. </p>

Incision Sensor Using Conductive Tape for Cricothyrotomy Training Simulation With Quantitative Feedback

Cricothyrotomy procedures, involving risky incisions on the neck skin and internal membranes, require rigorous training. In this paper, a novel incision sensor measuring the incision path in a cricothyrotomy training simulation is proposed. The sensor provides quantitative feedback to trainees on their incision practice, enhancing the effectiveness of the simulation. The sensor measures the electric potential, which decreases monotonically along the direction of current flow on the conductive material at the incision point, and converts it to coordinate values, based on the relationship between the electric potential and the position. The sensor comprises three layers of conductive tape, which are electrically isolated by two dielectric layers, and is fabricated as a thin film. The first two conductive layers (driving layers) are alternately energized to create distributions of electric potential in the $x$ or $y$ directions across the sensor plane. The third conductive layer (sensing layer), placed under the driving layers, transfers the electric potential to the output channel of the sensor at the point where a metal blade creates a short circuit between the energized driving layer and the sensing layer. The alternating measurements are converted to $x$ and $y$ coordinates of the incision position. The experiments for characterization and performance validation were performed using sensor prototypes fabricated with the proposed design and fabrication procedures. The experimental results show that the proposed sensor facilitates the measurement of the incision paths aligned with and diagonal to the $x$ and $y$ axes within root mean square errors of 0.98 and 1.03 mm, respectively.

Design of triple-band-pass frequency selective structure based on spoof surface plasmon polariton

In this paper, a triple-band-pass frequency selective structure is designed by combining traditional frequency selective surfaces (FSSs) with the spoof surface plasmon polariton (SSPP) guiding structure array. The FSSs consist of Jerusalem cross unit cell array with dual-band-pass property. And the SSPP guiding structure array is composed of vertical metallic blade structure array with high-efficiency transmission by engineering the dispersion of SSPP. By arranging the FSSs above the SSPP guiding structure array, a null located between the two passbands is introduced, resulting in a triple-band-pass characteristic. Furthermore, the triple-band-pass frequency selective structure is simulated, fabricated and measured. Both the simulated and measured results agree well, and verify that the transmissivities are all higher than -0.5dB in three frequency ranges: 2.42-2.90GHz, 5.57-5.85GHz and 9.48-9.85GHz. And the transmissivities of stopbands are lower than -10dB in three frequency ranges: 3.12-5.46GHz, 6.65-7.89GHz and 10.32-15.20GHz.

Tooth grooves, occlusal striations, dental calculus, and evidence for fiber processing in an Italian eneolithic/bronze age cemetery

We conducted a systematic macroscopic and microscopic examination of occlusal and para-occlusal wear in a large dental sample (n = 3,014) from 217 individuals dated to the Early Bronze age site of Gricignano d'Aversa, Italy. We used macroscopic and microscopic techniques to document nondietary occlusal and para-occlusal wear and to analyze calculus inclusions in some of the teeth. In combining an analysis of the wear with the calculus inclusions we linked the specific wear to the likely fiber that was involved in producing it. Teeth and their high resolution epoxy casts were analyzed through SEM and reflected light microscopes. Nineteen individuals (fifteen with activity induced dental modifications and four as a control sample) were examined for the presence of calculus inclusions. Activity induced dental modifications (AIDMs), notches, grooves and micro-striations, were found in the 62.2% of the adult females, in 21.2% of the adults of unknown sex and in a single male. We found the full spectrum of dental manipulations from very minor nonocclusal wear in some young individuals to severe attrition at the other extreme. The width of the striations and grooves, mostly on the upper incisors, suggests a craft activity involving fibers and thread production and manipulation. From the dental calculus of two females with grooves and striations, we extracted three fragments of fibers, identified as hemp (Cannabis, sp.). Previously from Gricignano woven hemp fibers were found on both surfaces of a metal blade associated with a male burial. This study found the co-occurrence of tooth AIDMs and the actual fibers preserved in the dental calculus. As more work is done analyzing dental calculus in a variety of humans, it is apparent that this biological material holds rich resources documenting non-dietary habits.

Residual soiling mass after dung removal in dairy loose housings: Effect of scraping tool, floor type, dung removal frequency and season

Clean floors in dairy housing have a positive impact on claw health, cleanliness of the animals and ammonia-emission reduction. Key indicator of cleaning quality is residual soiling mass, i.e. the manure remaining on the floor after dung removal. The aim of this study was to show the effects of scraping tool, rubber mat type, solid floor type, dung removal frequency and season on residual soiling mass. The comparison two scraping tools and two rubber mat types in winter showed that the rubber mat type (p = 0.001) and the scraping tool (p = 0.001) influenced the residual soiling mass. The cleaning quality was better on the common than on the soft rubber mat and the hard rubber lip left less residual soiling mass versus the metal blade (means: 174 vs. 230 g m−2 on common; 230 vs. 243 g m−2 on soft rubber mat). Further two floor types (with and without 3% slope) and two dung removal frequencies (three and 12 times per day) were investigated in three seasons. The statistical analysis proved the season as significant (p

Designing A Video Laryngoscope Imaging System with A 7-mm Blade for Neonatal Patients

In case of ventilation failure while using a resuscitation mask after a newborn infant is pushed from the birth canal, a doctor must perform intubation in the infant as well as other emergency measures to keep the baby alive. However, because of the considerably small mouth area of a newborn or premature infant, doctors are unable to view the glottis entrance, which can lead to a failed intubation or long intubation time, thereby resulting in either a drop in oxygen levels or a rise in the intrathoracic pressure. Although a normal video laryngoscope with a 12-mm metal blade certainly improves this type of difficult intubation, doctors often complain that the depth of field of this laryngoscope is insufficient and the width of the blade is too wide for performing intubation on neonatal patients. Therefore, in this study, we developed a video laryngoscope imaging system with two modules, an ultrathin 7-mm metal blade, and an optical imaging system. The core technology of this system includes a 2.5-mm optical lens and verification of imaging quality. To allow a physician to immediately determine an infant’s airway position and prevent binocular disparity while performing intubation, the optical properties of monolithic lenses were simulated while designing the imaging system, thereby allowing the physician to obtain a clear and undistorted image within the field of view.

Analysis of increasing efficiency of modern combined cycle power plant: A case study

The paper presents a comprehensive thermodynamic analysis of various gas turbine improvements in a modern combined cycle power plant designed to increase its electrical efficiency. The power plant was analyzed for use in: open air (convection, film and transpiration) cooling without and with cooling air cooler, closed air cooling, closed steam cooling and sequential combustion. The combined cycle power plant is equipped with a 200 MW gas turbine and a subcritical heat recovery steam generator with steam reheating. This article presents the effect of coolant cooling (air) and its use in the steam cycle of the combined cycle power plant. The influence of the higher permissible metal blade temperature in gas turbine on the electric efficiency of the gas turbine as well as the entire combined cycle power plant was also shown. It has also been proven that using industry - known solutions such as steam cooling and sequential combustion, the net electric efficiency of a combined cycle power plant can reach 0.63–0.65.

아르키메데스 풍력발전기 강성설계에 관한 연구

We have designed the structural shapes of a spiral blade and the frame to be used in an Archimedes wind-power system with the objective of increasing its mechanical strength. A conical roll-bending forming process was introduced to fabricate a metallic spiral blade, based on an incremental stepwise approach. From this process, the complicated spiral blade was constructed, and it could be applied to the wind-power mill. We proposed a few structural design concepts for improvement of the mechanical strength of the blade and frame. Fixing rods between the blades increased the natural frequency of the blades three-fold, compared to the original model with no rods. Also, the strength of the frame was increased by introducing edge-flanges with a height greater than 20 mm. This study will be helpful to industrial engineers interested in the structural design of a wind-power system in understanding the structural design process.

Enhancing stab resistance of thermoset–aramid composite fabrics by coating with SiC particles

Aramid has been proved to have excellent ability to protect against ballistic threats however, it has poor puncture resistance. In this research, flexible fabric materials with outstanding stab resistance were prepared with thermoset–aramid composites coated with SiC particles. The stab resistance and mechanical properties of the flexible fabric composites were evaluated. Results showed that the stab resistance of the thermoset–aramid fabrics was effectively improved by the introduction of SiC particles; however, the tear force was slightly decreased. Composites coated with 20 wt.% SiC particles exhibited the best stab resistance against knife cut. Scanning electron microscopy observation showed that the irregular SiC particles were embedded into the gaps among aramid fibers. The increased stab resistance was ascribed to the fact that the introduced SiC particles with hard and refractory nature could highly enhance the fiber-to-fiber friction and blunt the sharp metal blade by abrasion.

Designing a video laryngoscope imaging system with a 7mm blade for neonatal patients

When a newborn infant has been pushed from the birth canal due to ventilation failure while using a resuscitation mask, the doctor must implement infant intubation and other emergency steps to keep the baby alive. However, due to the excessively small mouth area of a newborn or premature infant, the doctors are unable to view the glottis entrance, which can lead to either a failed intubation or longer intubation time, thereby resulting in either a drop in oxygen levels or a rise in intrathoracic pressure. Although the normal video laryngoscope with a 12mm metal blade certainly improves this type of difficult intubation, nevertheless, doctors often complain that the depth of field (DOF) is insufficient and the width of the blade is too wide when performing intubation on neonatal patients. Therefore, this study aims to develop two modules of infant’s video laryngoscope, an ultra-thin 7mm metal blade and an optical imaging system, the core technology of which includes an optical design of a 2.5mm lens and verifications of imaging quality. In order to allow physicians to determine the infant’s airway position immediately and to avoid the binocular disparity from a physician while giving intubation, this study has simulated the optical properties of monolithic lenses while designing the imaging system, allowing the doctor to have a clearer and undistorted image within the field of view.

Conical roll-twist-bending process for fabrication of metallic Archimedes spiral blade used in small wind power generator

We propose a novel conical roll-twist-bending (RTB) process to fabricate a metallic Archimedes spiral blade which has variable curvatures on its surface, and it is a key element of a novel wind power generator having a remarkably higher efficiency of about 34% compared with conventional wind power systems. The RTB system consists of a pair of conical rollers (upper and lower sides) and cylindrical twist-bending rollers in the both lateral sides. With the help of forming analysis results, multi-step regional forming method was utilized to fabricate the blade. Also, the process parameters were optimized by a response surface methodology. In this work, we installed the experimental equipment of RTB process, and it was experimentally proven that the developed RTB process was capable of producing a spiral blade with a shape error less than approximately 5%. Furthermore, we believe that the RTB process can be utilized to fabricate diverse sheet metal structures having continuously changing curvatures for various applications.

Effort towards symmetric removal and surface smoothening of 1.3-GHz niobium single-cell cavity in vertical electropolishing using a unique cathode

A detailed study on vertical electropolishing (VEP) of a 1.3-GHz single-cell niobium coupon cavity, which contains six coupons and four viewports at different positions, is reported. The cavity was vertically electropolished using a conventional rod and three types of unique cathodes named as Ninja cathodes, which were designed to have four retractable blades made of either an insulator or a metal or a combination of both. This study reveals the effect of the cathodes and their rotation speed on uniformity in removal thickness and surface morphology at different positions inside the cavity. Removal thickness was measured at several positions of the cavity using an ultrasonic thickness gauge and the surface features of the coupons were examined by an optical microscope and a surface profiler. The Ninja cathode with partial metallic blades was found to be effective not only in reducing asymmetric removal, which is one of the major problems in VEP and might be caused by the accumulation of hydrogen (${\mathrm{H}}_{2}$) gas bubbles on the top iris of the cavity, but also in yielding a smooth surface of the entire cavity. A higher rotation speed of the Ninja cathode prevents bubble accumulation on the upper iris, and might result in a viscous layer of similar thickness in the cavity cell. Moreover, a higher electric field at the equator owing to the proximity of partial metallic blades to the equator surface resulted in a smooth surface. The effects of ${\mathrm{H}}_{2}$ gas bubbles and stirring were also observed in lab EP experiments.