Low-cost Engineering Research Articles

Overview and recent applications of the miniaturized HiPoLas ignition system

The requirements of the space industry for reusable, low cost or clustered engines have triggered high interest in a laser ignition system capable of multi-point ignition. The miniaturized SAL HiPoLas laser ignition system developed for single-point direct-plasma ignition has recently been enhanced towards a fiber coupling, multiplexing, and distribution system. A brief history of the HiPoLas development with an overview of the latest, highly miniaturized generation V ignition system is shown. Applications of the miniaturized ignition system, summarizing more than 10 years of development in the field of rocket engine laser ignition, as well as the first results of a recently developed prototype of a fiber distribution system, based on diffractive optical elements, are presented.

Dynamic Intelligent Analysis of Single-Column Pier Bridges Considering Vehicle–Bridge Interaction

With its advantages of low engineering cost, minimal space occupancy, and aesthetically pleasing shape, the single-column pier bridge is frequently utilized in urban viaducts and interchange ramps. Due to structural peculiarities, the bridge subjected to eccentric loading, flexural and torsional interaction, and centrifugal force may undergo tipping accidents. To better comprehend the overturning resistance of the bridge, the vibration governing equation of the bridge (idealized as an orthotropic thin plate with point supports in the domain model) is established considering vehicle–bridge interaction. An approximate dynamic analysis formula is subsequently derived via a hybrid method using the grey wolf optimizer. Compared with the outcomes of finite element analysis, the maximal deviation arising from this derived analytical formula is approximately [Formula: see text]% with the greater discrepancy being observed in scenarios featuring minimal support reactions. Compared with the finite element method, the proposed method in this study has higher computational efficiency with precision. This analytical solution is then utilized in the parametric study to scrutinize the influences of span, road surface roughness, and vehicle velocity on a single-column pier bridge under four vehicles. The analysis findings indicate that the proposed approach is reasonably precise, remarkably efficient, and efficacious.

Effectiveness of a novel composite filler to enhance phosphorus removal in constructed wetlands.

Improving the adsorption performance of wetland fillers is of great significance for enhancing pollutant removal in constructed wetlands. Currently, limited by complex preparation processes and high costs, large numbers of high adsorption fillers studied in lab are difficult to be applied in practical engineering. In this study, a newly low-cost and efficient phosphorus removal composite wetland filler (CFB) is prepared by using industrial and agriculture waste (steel slag and oyster shells) and natural ore (volcanic rock) as raw materials. The results show that phosphorus removal efficiency was largely enhanced by synergistic effects of steel slag, oyster shells, and volcanic rock, and it was mainly influenced by the proportion of each component of CFB. Based on the fitting of the classical isothermal equation, the adsorption capacity of CFB is 18.339 mg/g. The adsorption of phosphorus by CFB is endothermic and spontaneous, and there are heterogeneous surfaces and multi-layer adsorption processes, as well as pH value and temperature, are free from the influence on CFB phosphorus removal. During the practical wastewater application experiments, the phosphorus removal rate of the CFB-filled constructed wetland apparatus (CW-A) can reach 94.89% and is free from the influence on the removal of other pollutants (COD, TN, and NH3-N) by the system. Overall, the prepared CFB is of excellent decontamination effect, an extremely simple preparation process, low cost, and sound practical engineering application potential, providing new ideas and approaches for enhancing the phosphorus removal capacity and waste resource utilization of constructed wetland systems.

Progress in and research direction of key technologies for normal-pressure shale gas exploration and development

Normal-pressure shale gas is an important object of shale gas reserves and production increase with broad resource prospects in China, but its large-scale benefit development is still confronted with technical bottlenecks. To promote the large-scale benefit development of normal-pressure shale gas, this paper systematically sorts out and summarizes the research achievements and technological progresses related to normal-pressure shale gas from the aspects of accumulation mechanism, enrichment theory, percolation mechanism, development technology, and low-cost engineering technology, and points out the difficulties and challenges to the benefit development of normal-pressure shale gas in the complex structure zones of southern China, by taking the shale gas in the Southeast Chongqing Area of the Sichuan Basin as the research object. In addition, the research direction of normal-pressure shale gas exploration and development is discussed in terms of sweet spot selection, development technology policy, low-cost drilling technology and high-efficiency fracturing technology. And the following research results are obtained. First, the accumulation mechanism of normal-pressure shale gas is clarified from the perspective of geological exploration theory; the hydrocarbon accumulation model of generation, expulsion, retention and accumulation is established; the enrichment theory of “three-factor controlling reservoir” is put forward; and the comprehensive sweetspot target evaluation system is formed. Second, as for development technology, the development technology policies of “multiple series of strata, variable well spacing, long horizontal section, small included angle, low elevation difference, strong stimulation and pressure difference controlling” are formulated. Third, as for drilling engineering, the optimal fast drilling and completion technology with “secondary structure + radical parameter + integrated guidance + unpressured leak-proof cementing” as the core is formed. Fourth, as for fracturing engineering, the low-cost and high-efficiency fracturing technology with “multi-cluster small-stage + limited-entry perforating + double temporary blocking + high-intensity sand injection + fully electric” as the core is formed. Fifth, normal-pressure shale gas is characterized by complex geological conditions, low pressure coefficient and gas content, poor resource endowment and so on, but its resource utilization still faces a series of challenges, such as uncertain productivity construction positions, low single-well productivity and ultimate recoverable reserve, high investment cost and poor economic benefit. In conclusion, the key research directions to realize the large-scale benefit development of low-grade normal-pressure shale gas are to deepen the research on the enrichment and high yield mechanism and sweet spot selection of normal-pressure shale gas, strengthen the research on the benefit development technology policy based on percolation mechanism and the key technologies for low-cost drilling, accelerate the research and development of the key technologies for low-cost and high-efficiency fracturing, and implement cost reduction and efficiency improvement continuously.

New Models of Higher Education for Low-Income countries

In low-income countries, increasing access to higher education is particularly challenging. While tertiary education may boost a country's prosperity, the high cost of education, despite subsidies, remains a barrier to access. The digitisation of existing approaches to tertiary education is insufficient, and a more radical approach is needed.
 
 The Atlantic Technological University has been working on two approaches that hold potential for addressing this challenge. A work-based degree in engineering has placed a student in Mozambique in a mining company, where they will learn the required practical engineering skills and study online. Although this approach will allow the student to earn an income as they study, the fees will still be significant as it is based on existing forms of online learning. Separately, the university is developing a 2-year low-cost Engineering programme based on free online content, modest payment for examinations, and supervision of a capstone project.
 
 This paper focuses on the design of these programmes and the challenges involved. Attendees will learn how these new models of higher education for low-income countries could potentially address the cost barrier to access and significantly increase participation in tertiary education, leading to improved prosperity and economic growth.

Development of Self-Sustaining Improvement Material for a Mud Film of the Weathered Soil of Red Beds

Red beds are widely distributed in various regions of China. Adapting measures to adjust to local conditions and using nearby materials to ecologically protect slopes, mines, and other engineering projects are methods advocated by environmental protection. A mud film of the weathered soil of red beds with improved materials for insulation and entropy preservation is commonly used in engineering ecological protection, and its self-sustainability is an important indicator with which to measure the protective effect; however, most of the commonly used improvement materials in production have high concentrations of chemical substances and high costs, causing environmental pollution. In response to this issue, this study has developed four new composite improved materials using waste paper as raw material. The low temperature resistance (−20 °C, 0 °C), high temperature resistance (40 °C, 60 °C, and 80 °C), and recyclability (dry and wet cycle: zero, one, two, and three times) of the four materials were tested. Under the conditions of changing the addition amounts of four new self-developed composite materials (0 g, 10 g, 20 g, 30 g, 40 g, 50 g, 60 g, 70 g, 80 g, 90 g, and 100 g), experiments were conducted on the thin-layer property, corrosion resistance, and flexibility of the mud film of weathered soil of red beds, and they were compared with conventional materials studied by the team in the early stage. At the same time, outdoor on-site testing was conducted. The experimental results indicate that the self-developed new composite improvement material has a good improvement effect on the self-sustainability and ecological protection effect of the mud film of weathered soil of red beds. This article summarizes the improvement mechanism and control factors of self-developed new composite materials in the self-sustainability of the mud film of the weathered soil of red beds, improves the suitability of engineering ecological protection, and develops green and low-cost engineering ecological protection technology.

Non-graphitized carbon/Cu2O/Cu0 nanohybrids with improved stability and enhanced photocatalytic H2 production

Cu2O is a highly potent photocatalyst, however photocorrosion stands as a key obstacle for its stability in photocatalytic technologies. Herein, we show that nanohybrids of Cu2O/Cu0 nanoparticles interfaced with non-graphitized carbon (nGC) constitute a novel synthesis route towards stable Cu-photocatalysts with minimized photocorrosion. Using a Flame Spray Pyrolysis (FSP) process that allows synthesis of anoxic-Cu phases, we have developed in one-step a library of Cu2O/Cu0 nanocatalysts interfaced with nGC, optimized for enhanced photocatalytic H2 production from H2O. Co-optimization of the nGC and the Cu2O/Cu0 ratio is shown to be a key strategy for high H2 production, > 4700 μmoles g−1 h−1 plus enhanced stability against photocorrosion, and onset potential of 0.234 V vs. RHE. After 4 repetitive reuses the catalyst is shown to lose less than 5% of its photocatalytic efficiency, while photocorrosion was < 6%. In contrast, interfacing of Cu2O/Cu0 with graphitized-C is not as efficient. Raman, FT-IR and TGA data are analyzed to explain the undelaying structural functional mechanisms where the tight interfacing of nGC with the Cu2O/Cu0 nanophases is the preferred configuration. The present findings can be useful for wider technological goals that demand low-cost engineering, high stability Cu-nanodevices, prepared with industrially scalable process.

Corrosion inhibition of mild steel in 0.5 M HCL by substituted 1,3,4-oxadiazole

Organic inhibitors are normally used to inhibit the corrosion of metals or alloys in an aqueous environment. The anti-corrosive property of 5((6-Methyl-2-oxo-2H-chromen-4yl)thiomethyl)-2((N-(3-methyl-quinoxalin-2(1H)one)yl) methyl)-1,3,4-oxadiazole (MOD) on mild steel (MS) was studied. Which acts as a novel corrosion inhibitor for MS in 0.5 M Hydrochloric acid (HCl) solution and corrosion behavior in the temperature range of 303–323 K, without and with the MOD inhibitor, was calculated using potentiodynamic polarization, electrochemical impedance spectroscopy, and weight loss measurements. The surface topography of mild steel with, and without MOD was investigated by Scanning electron microscopy (SEM) technique. The inhibitory efficiency increases with an increase in MOD (50 ppm) concentration and showed a maximum of 84.85% in 0.5 M HCl at 303 K. The variation in kinetic and thermodynamic properties of MOD on MS indicates chemisorption and its mixed kind of inhibition activity followed by the Langmuir adsorption isotherm. The experimental results are supported by Density functional theory (DFT) simulations, indicating a potential corrosion inhibition behaviour of MOD on MS in acidic environments. A suitable mechanism for the corrosion inhibition of mild steel was put forth. The corrosion inhibition mechanism of mild steel was discussed. Mild steel is a low-cost engineering material that can be regularly used for various applications such as construction, advertising, vehicles, furniture, fencing, and more in various conditions, including mild acidic ones with a little caution.

Photoelctrochemically Manufactured HgO/Cu2O Monolayer with Ameliorate Photovoltaic Features

This writing report acquaint the chances for promoting efficiency betterment of p-Cu2O electrode for PECs likewise in production of hydrogen gas, using HgO/Cu2O hetero-structure. The arrangement was accomplished by both bracing the surface of p-Cu2O plate embattled through thermal oxidization of copper sheet and also acquiring low cost, effortless and low impairment engineering deposition for utilizing HgO as absorber layer. The altitudinous efficiency of 4.80% and open circuit voltage of 185MV were incurred in an HgO/Cu2O hetero-structure PEC solar cell commence with copper foil thickness (0.1mm) substrate for preparing the Cu2O thin film under oxygen gas pressure at 950℃ by thermal oxidizing techniques. It is requisite to augmented the interface at the hetero-structure junction to accomplished a soaring efficiency in HgO/Cu2O/HgO semiconductor beside multiplicative the parallel resistance and remittent the series resistance.Keywords: thermal oxidation, cuprous oxide, hetero-structure, J-V characteristic, photoelectrochemical, annealing, etching.

Investigating the Mechanical Property and Enhanced Mechanism of Modified Pisha Sandstone Geopolymer via Ion Exchange Solidification

The Yellow River has the highest sediment concentration in the world, and the Yellow River coarse sediment mainly comes from a particular kind of argillaceous sandstone, Pisha sandstone. This paper reports an investigation of the possibility of development of low-cost engineering materials using Pisha sandstone via ion exchange modification. The effect of modifiers with different concentration on the inhibition of volume expansion and the strength enhancement of modified Pisha sandstone were studied via ion exchange solidification. The effects of the concentration of ten types of modifier solutions and curing age were considered. The hydration of the mineral components, particle surface potential and reaction products were studied, respectively, by XRD, zeta potential, TG/DTG and SEM. Expansion volume and shear strength tests were conducted to assess the volume stability and mechanical property of modified Pisha sandstone. It showed that the expansion of Pisha sandstone was controlled and that the volume stability and shear strength were improved via ion exchange modification. The results of XRD, TG/DTG and SEM showed that the spacing of the crystal layers of the Pisha sandstone clay mineral and the mass lost had decreased significantly. When the concentration of the modifier was 0.05 mol/L, the volume reduced by 54.55% maximum and the shear strength reached the peak of 138 kPa.

Numerical and experimental investigation on the drive mechanisms of Alfa type Stirling engines

ABSTRACT Stirling technology has applications in both renewable energy and waste heat recovery systems. The applicability of Stirling engines in these fields depends on the development of more efficient external combustion machines using renewable energy sources or waste heat. In this study, a new drive mechanism is proposed for the low cost, low weight, low volume and high-efficiency Stirling engines. The effects of the new drive mechanism on the performance parameters of the alpha-type kinematic Stirling engine are investigated, experimentally and theoretically. The mathematical model is validated by using the experimental results. The torque values for different piston forces are presented and compared with that of the conventional slider-crank mechanism. The results show that the torque value of the engine using the new drive mechanism increases by up to 3.66 times compared with that of the conventional slider-crank mechanism.

Tröger's base polymer blended with poly(ether ketone cardo) for high temperature proton exchange membrane fuel cell applications

Developing membrane electrolyte materials with high performance and low cost is a key factor in promoting the application and commercialization of the high temperature proton exchange membrane fuel cell (HT-PEMFC). In this work, a Tröger's base (TB) polymer is synthesized from commercially available and low-cost 4,4′-diamine-3,3′-dimethyl-biphenyl (DMBP) and dimethoxy methane in trifluoroacetic acid via a one-pot TB polymerization reaction under mild conditions. The obtained polymer is composited by TB unit and DMBP moiety (named as DMBP-TB), which occupies a good organic solubility, high thermal stability and excellent chemical resistance. Due to the built-in bicyclic amine rings and intrinsic microporous structure, the pure DMBP-TB membrane exhibits a remarkable phosphoric acid (PA) doping content as high as 1077% in 85 wt% PA solution at room temperature. However, the excessive swelling and poor mechanical integrity hinder the PA doped DMBP-TB membrane as the HT-PEM. Thus, the commercial and low-cost engineering thermoplastic of poly(ether ketone cardo) (PEKC) is employed as the enhanced material to prepare DMBP-TB blend membranes. The DMBP-TB/50%PEKC/149%PA membrane displays an anhydrous conductivity of 0.061 S cm−1 at 180 °C and a tensile strength of 8.7 MPa at room temperature, which enables H2–O2 fuel cell with a peak power density of 536 mW cm−2 at 180 °C without backpressure, suggesting the utility for HT-PEMFCs.

Low-cost engineering experimentation laboratory kit designed for at-home project-based learning

During the Spring 2021 semester, the third-year Engineering Experimentation course at the Cooper Union was administered virtually due to the COVID-19 pandemic. The online format presented many challenges to teaching a hands-on, project-based laboratory class. To provide students with the experience of performing real engineering experiments, a low-cost laboratory kit was assembled and sent to each student. The kit included a microcontroller to serve as a data acquisition device, two electret microphones, and electronic components necessary to collect acoustic data. All of the students used this equipment to run a speed of sound laboratory by determining the time an impulsive signal took to travel between the microphones placed a known distance apart. For the final project, two teams of students conducted independent research of acoustic phenomena and further developed low-cost solutions. One team constructed an impedance tube from PVC pipe to measure the absorption characteristics of unknown materials. Normal incidence sound absorption coefficients were calculated for four frequencies by measuring the standing-wave ratio in accordance with ASTM standard C384. The second team built two experimental apparatuses to demonstrate the Doppler Effect. Both at-home Doppler experiments were able to clearly show the shift of the observed frequency of a moving source.

Geological and engineering controls on the differential productivity of CBM wells in the Linfen block, southeastern Ordos Basin, China: Insights from geochemical analysis

In view of the differential productivity of coalbed methane (CBM) wells in the Linfen block on the southeastern margin of the Ordos basin, geochemical analysis is performed to determine the hydrodynamic condition of coal reservoirs, identify the water and gas source of commingled wells, reveal different pressure drop mechanisms, and finally clarify the geological and engineering controls on the production performance. The positive correlations between average daily gas production and the concentrations of Na+, Cl‾, TDS, Sr, and Ba imply that strong hydraulic closure is the premise of high productivity. There is no obvious relationship between water and gas production. Commingled (5 + 8#) wells tend to produce more water than single-layered (5#) wells, because the No. 8 coal seam has more active hydrodynamic condition, which is proven by the lighter δ2H and δ18O and smaller Sr/Ba ratio of waters from commingled wells. The difficulty in pressure drop funnel expansion is the primary constrains for the single-layered wells, which is only resolved by the horizontal wells located in low structural positions at present characterized by increasing trends of TDS, Na+ and Cl‾ contents during drainage. The faster the ion concentration rises, the faster the pressure drop funnel expands and a high peak daily gas production can be quickly achieved. The L-shaped horizontal well is thought to be the most suitable well type due to its high gas yield, low time investment and engineering cost. Due to hydrodynamic heterogeneity, commingled wells often show strong interlayer interference and a change in the water-producing horizon from 5# to 8# coal, which is manifested in the tendency of Cl‾, Na+, and TDS to increase first and then decrease. By selecting superior lithologic assemblages and avoiding strong aquifers, relatively continuous and stable production of commingled wells can also be achieved. This study provides a basis for the further development of CBM in the Linfen block and enriches engineering geochemistry theory.

Experimental Study on Vibration Absorption Performance of Floating Slabs of Vibration Isolation Pads in Metro Shield Tunnels

The monolithic track bed with isolated damping pad and floating slab is a common design of urban subways in recent years.The type of track bed, urban subway lines usually pass through densely populated areas of the city, and subway trains.In the course of driving, it is inevitable that large track vibration noise will be produced. In order to reduce the impact of track vibration noise on the daily life of surrounding residents, noise reduction measures must be considered during track design. Isolated shock absorber floating board The monolithic track bed is one of them. Compared with the steel spring floating slab monolithic track bed, it has the technical characteristics of “low engineering cost, more convenient construction, and good noise reduction effect”. In order to study its damping effect, we selected two working conditions of straight line and curve for comparison. It can be seen from the comparison results with the ordinary track bed: (1) The acceleration level of the shock-absorbing cushion tunnel wall in the straight section is greater than the ordinary track bed section within 1∼10Hz, and is close to the ordinary track bed section within 12.5∼20Hz, at 25 It is smaller than the section of ordinary track bed within ∼1000Hz. (2) The maximum Z-vibration level measured from the tunnel wall is most suitable for evaluating the seismic source intensity of the subway, and the seismic source intensity of the subway line is 65.69 dB.

An Effective and Low-Cost Artificial Interface Engineering for Garnet-Based Solid-State Li Metal Batteries

An Effective and Low-Cost Artificial Interface Engineering for Garnet-Based Solid-State Li Metal Batteries

Mechanical, dielectric, and hydrophobicity behavior of coconut shell biochar toughened Caryota urens natural fiber reinforced epoxy composite

AbstractHigh toughness epoxy bio‐composites were prepared using Caryota urens fiber and biochar particle for light weight and low cost engineering applications. The main aim of this research was to study the effect of adding biochar along with C. urens fiber in epoxy resin composite and its properties. The biochar used in this present study was prepared from coconut shell using pyrolysis process. The composites prepared with 5 vol% of biochar gives highest tensile strength and modulus of 172 MPa and 6.7 GPa. Similarly, the biochar of 7 vol% in epoxy resin reduced the wear volume to the greater extend. Moreover, a highest dielectric constant and loss factor of 6.2, 1.6, and a thermal conductivity of 0.33 W/mK with high hydrophobic contact angle of 70° was observed for composite made using 7 vol% of biochar. These improved dielectric, mechanical, barrier and tribological properties composite could be used as microwave shielding material in electronic gadgets, signal processing units and other telecommunication devices as shielding material with good mechanical properties required.

Changing driver yielding behavior on a city-wide basis

ABSTRACT This study evaluated a program to increase driver yielding to pedestrians in crosswalks on a city-wide basis in two cities located within large metropolitan areas. A multifaceted treatment was used to increase yielding in both cities that consisted of highly visible enforcement, public posting of the percentage of drivers yielding to pedestrians each week along with the record on highway signs, and a low-cost engineering treatment. Enforcement and the low-cost engineering component were only introduced at half the sites termed treatment sites while these treatments were not introduced at the remaining sites that were termed generalization sites. Feedback on the number of drivers yielding to pedestrians in each city was presented at signs on busy roadways within the city and a limited amount of educational outreach to the community was implemented on a city-wide basis through parent outreach. Data were collected using staged crossings made by research assistants. Data were also collected on natural crossing made by members of the community. Data for staged crossings at the sites that received enforcement and the engineering treatment increased from a baseline level of 28% to 67% in the first city and from 29% to 74% in the second city. A more modest change occurred at the generalization sites. Data for natural crossings increased from 24% to 80% in the first city and from 48% to 78% in the second city at treatment sites. Similar changes occur for natural crossings at the generalization sites.

Optimization of parabolic trough solar power plant operations with nonuniform and degraded collectors

In a commercial parabolic trough solar power plant (PTSPP), the solar field (SF) is large-scaled and consists of hundreds of parabolic trough collector (PTC) loops. The PTSPP performance is determined by an appropriate operation strategy of the SF, which is implemented by adjusting the outlet temperature, the flowrate, and the flow distribution through the valves and pump to make the PTSPP output cost-effective. Majority of the published literature study the behavior of the SF with an assumption that all the PTC loops have uniform perfect performance. Due to the lack of appropriate model and algorithm, although operating with nonuniform and degraded PTCs is inevitable for a realistic SF, there is scarcely any literature studies how to develop an optimal operation strategy under this situation. The present paper aims at solving this problem by establishing a PTSPP model and developing an improved operation strategy (IOS). The PTSPP model consists of an improved thermal hydraulic model of the SF and a simplified but effective model of the power block, and the IOS combines the features of both global and distributed operation strategy. Based on the model and the IOS, the mechanism of optimization is illustrated in a uniform case, and then according to the comparison and analysis, the most appropriate strategy for the nonuniform case is determined among three representative strategies. Compared with the traditional operation strategy, the chosen strategy can improve the net electric generation by 3.4% with the low computational cost and good engineering feasibility.

Sustainable Sandwich Composites Manufactured from Recycled Carbon Fibers, Flax Fibers/PP Skins, and Recycled PET Core

European union end of life vehicle directive mandates the use of more sustainable/recyclable materials in automotive industries. Thermoplastics matrix-based composites allow recyclability of composites at the end of life; however, their processing technology is more challenging than thermoset composites. Manufacturing process and mechanical testing of sustainable sandwich composite made from sustainable materials: flax, recycled carbon fiber, polypropylene, and recycled PET foam are presented in this article. High pressure compression molding with adhesive thermoplastic polymer film was used for manufacturing sandwich composite skin. The recycled PET foam core was integrated/joined with the skin using a thermoplastics adhesive film. A three-point bending test was conducted to compare the flexural properties. The results show that such sustainable sandwich composites will be an excellent material for truck side panel to operate in adverse wind/storm conditions. The sustainable sandwich composite can potentially be an excellent candidate for the fabrication of light-duty, lightweight, and low-cost engineering structures in automotive industry to meet the EU end of life requirements.