An advanced ash fusion study on the melting behaviour of coal,oil shale and blends under gasification conditions using picture analysis and graphing method

This study investigates the potential of solid fuel blending as an effective approach to manipulate ash melting behaviour to alleviate ashrelated problems during gasification,thus improving design,operability and safety.The ash fusion characteristics of Qinghai bituminous coal together with Fushun,Xinghua and Laoheishan oil shales(and their respective blends)were quantified using a novel picture analysis and graphing method,which incorporates conventional ash fusion study,dilatometry and sintering strength test,in a CO/CO_(2)atmosphere.This imagebased characterisation method was used to monitor and quantify the complete melting behaviour of ash samples from room temperature to 1520℃.The impacts of blending on compositional changes during heating were determined experimentally via Xray diffraction and validated computationally using FactSage.Results showed that the melting point of Qinghai coal ash to be the lowest at 1116℃,but would increase up to 1208℃,1161℃and 1160℃with the addition of 30%50%of Laoheishan,Fushun,and Xinghua oil shales,respectively.The formation of highmelting anorthite and mullite structures inhibits the formation of lowmelting hercynite.However,the sintering point of Qinghai coal ash was seen to decrease from 1005℃to 855℃,834℃,and 819℃in the same blends due to the formation of lowmelting aluminosilicate.Results also showed that blending directly influences the sintering strength during the various stages of melting.The key finding from this study is that it is possible to mitigate against the severe ash slagging and fouling issue arising from high calcium and iron coals by cogasification with a high silicaalumina oil shale.Moreover,blending coals with oil shales can also modify the ash melting behaviour of fuels to create the optimal ash chemistry that meets the design specification of the gasifier,without adversely affecting thermal performance.

Impacts of different drying strategies on drying characteristics,the retention of bio-active ingredient and colour changes of dried Roselle

The drying kinetics of Roselle （Hibiscus sabdariffa L） of variety Terengganu （UMKL-1） and the quality attribution of Roselle were studied. The experiments were conducted using four different drying methods, including solar greenhouse drying （SD）, solar greenhouse with intermittent heat pump drying （SIHP）, hot air drying （HA） and heat pump drying （HP）. Among the four drying methods, HP achieved the highest drying rate at a range from 0.054 g H20-（g DM）-1. rain-1 to 0.212 g H20-（g DM）-1. rain 1 while SD had the lowest drying rate, measured at 0.042 g H2O. （g DM） 1.min- 1. The analysis on colour kinetics revealed that there is no significant colour loss （p 〉 0.05） observed from HP＇s dried Roselle. Greater amount of flavonoid compounds i.e. protocatechuic acid was found in SD and SIHP dried finished product whereas HP＇s dried Roselle contains higher percentage of catechin as compared to other drying methods.

Development and Assessment of Thermoacoustic Generators Operating by Waste Heat from Cooking Stove

This paper presents the development and assessment of two low-cost, travelling wave, thermoacoustic generators operating by waste heat energy from cooking stove. One powered by waste heat from a propane-driven stove, the other powered by waste heat from a wood-burning stove. The propane-driven thermoacoustic generator was successfully demonstrated to produce approximately 15 watts of electricity using a commercial audio loudspeaker. The wood-burning thermoacoustic generator was successfully constructed and tested to generate a maximum of 22.7 watts of electricity under a pressurised condition. The latter has a high potential to be used by over 1.5 billion people in rural communities for applications such as LED lighting, charging mobile phones or charging a 12V battery. A comprehensive power assessment of the propane-driving generator as well as the development and performance assessment of the wood-burning generator are described throughout this article.

Intelligent Intercommunicating Multiscale Engineering: The Engineering of the Future

1.Introduction Despite being widely known and investigated as a computer science discipline,artificial intelligence(AI)has attracted incomparable interest from researchers in diversified areas[1].In 1950,Alan Turing raised the classic question that has inspired numerous researchers to date:“Can machines think?”[2].The ultimate benchmark of AI was set by Turing’s revised“imitation game.”

Do medical students studying in the United Kingdom have an adequate factual knowledge of basic life support?

BACKGROUND: Healthcare professionals have a duty to maintain basic life support(BLS) skills. This study aims to evaluate medical students' factual knowledge of BLS and the training they receive.METHODS: A cross-sectional, closed-response questionnaire was distributed to the fi rst-and fourth-year students studying at institutions in the United Kingdom. The paper questionnaire sought to quantify respondent's previous BLS training, factual knowledge of the BLS algorithm using five multiple choice questions(MCQs), and valuate their desire for further BLS training. Students received 1 point for each correctly identifi ed answer to the 5 MCQ's.RESULTS: A total of 3,732 complete responses were received from 21 medical schools. Eighty percent(n=2,999) of students completed a BLS course as part of their undergraduate medical studies. There was a signifi cant difference(P<0.001) in the percentage of the fourth-year students selecting the correct answer in all the MCQ's compared to the fi rst-year students except in identifyingthe correct depth of compressions required during CPR(P=0.095). Overall 10.3%(95% CI 9.9% to 10.7%) of respondents correctly identified the answer to 5 MCQ's on BLS: 9% of the first-year students(n=194) and 12% of the fourth-year students(n=190). On an institutional level the proportion of students answering all MCQ's correctly ranged from 2% to 54% at different universities. Eighty-one percent of students(n=3,031) wished for more BLS training in their curriculum.CONCLUSION: Factual knowledge of BLS is poor among medical students in the UK. There is a disparity in standards of knowledge across institutions and respondents indicating that they would like more training.

A Novel Solar Driven Micro-CliP System： A State of the Art Review

The state-of-the-art solar power system technologies are presented. Various methods of capturing solar energy using solar collectors such as parabolic trough collectors and dish collectors are reviewed. Combined heat and power （CHP） systems driven by concentrating solar absorbers and supplemented by biomass boilers are proving to be the most promising methods of domestic power generation, μCHP systems eliminate losses associated with power distribution and transmission opposed to the large scale power generation methods. The systems can utilize about 75% of solar energy to provide electric and thermal energy direct to end users. The driving potential behind μCHP systems is the thermal efficiency the systems can achieve and their market significance. Despite huge potential market for μCHP systems, the systems are yet to be seen available in commercial market. Hence the authors of this paper are currently developing such type of CHP system with electricity production being of prime importance.

Kinetic and thermodynamic investigations of CO2 gasification of coal chars prepared via conventional and microwave pyrolysis

This study examined an isothermal CO2 gasification of four chars prepared via two different methods,i.e.,conventional and microwave-assisted pyrolysis,by the approach of thermogravimetric analysis.Physical,chemical,and structural behaviours of chars were examined using ultimate analysis,X-ray diffraction,and scanning electronic microscopy.Kinetic parameters were calculated by applying the shrinking unreacted core(SCM)and random pore(RPM)models.Moreover,char-CO2 gasification was further simulated by using Aspen Plus to investigate thermodynamic performances in terms of syngas composition and cold gas efficiency(CGE).The microwave-induced char has the largest C/H mass ratio and most ordered carbon structure,but the smallest gasification reactivity.Kinetic analysis indicates that the RPM is better for describing both gasification conversion and reaction rates of the studied chars,and the activation energies and pre-exponential factors varied in the range of 78.45–194.72 kJ/mol and 3.15–102,231.99 s−1,respectively.In addition,a compensation effect was noted during gasification.Finally,the microwave-derived char exhibits better thermodynamic performances than the conventional chars,with the highest CGE and CO molar concentration of 1.30%and 86.18%,respectively.Increasing the pyrolysis temperature,gasification temperature,and CO2-to-carbon molar ratio improved the CGE.

Natural convection of SiO_2-water nanofluid in square cavity with thermal square column

A square with a thermal square column is a simple but nontrivial research prototype for nanofluid research. However, until now, the effects of the temperature of the square column on the heat and mass transfer of nanofluids have not been revealed comprehensively, especially on entropy generation. To deepen insight into this important field, the natural convection of the SiO2-water nanofluid in a square cavity with a square thermal column is studied numerically in this study. The effects of the thermal column temperature （T = 0.0, 0.5, 1.0, 1.5）, the Rayleigh number （ranging from 103 to 106）, and the volume fraction of the nanoparticle （varying from 0.01 to 0.04） on the fluid flow, heat transfer, and entropy generation are investigated, respectively. It is found that, no matter at a low or high Rayleigh number, the volume fraction of the nanoparticle shows no considerable effects on the flow field and temperature field for all the temperatures of the thermal column. With an increase in the volume fraction, the mean Nusselt number increases slightly. At the same time, it is found that, with an increase in the temperature of the thermal column, the average Nusselt number gradually decreases at all values of the Rayleigh number. Meanwhile, it is found that, at a high Rayleigh number, the heat transfer mechanism is the main parameter affecting the increase in the total entropy generation rather than the volume fraction. In addition, no matter at a high or low Rayleigh number, when T = 0.5, the total entropy generation is the minimum.

State-Independent Proof of Kochen–Specker Theorem with Thirty Rank-Two Projectors

The Kochen–Specker theorem states that noncontextual hidden variable theories are incompatible with quantum mechanics.We provide a state-independent proof of the Kochen–Specker theorem using the smallest number of projectors,i.e.,thirty rank-2 projectors,associated with the Mermin pentagram for a three-qubit system.

Evaluating the Nexus between Housing and Energy Sectors: The Comparison of Urban, Peri-Urban and Rural Housing Areas in Zhuhai, China

China has developed several housing policy reforms and has, in recent years, progressed further on developing policies to promote green strategies and energy-saving plans. The urban housing has much benefited from such reforms and plans, while rural housing has experienced minimal change in the past few decades. As a result, this study aims to identify and explore these differences, challenges, and implications that exist between three areas of urban, peri-urban, and rural in a particular case study in China. For this study, selected residential areas in the City of Zhuhai and its peri-urban and rural areas are selected as case studies. A questionnaire survey is conducted to analyze energy and housing conditions across the more prosperous urban, the dynamic and transitory peri-urban, and the less prosperous rural areas. The case studies are analyzed as comparative examples in a hot and humid sub-tropical area of Southern China. The study compares energy and housing conditions and argues potential possibilities and challenges for the future development of housing policy reforms that are the result of current housing development patterns and green strategy situation in China.

From Transitions to Transformation: A Brief Review of the Potential Impacts of COVID-19 on Boosting Digitization, Digitalization, and Systems Thinking in the Built Environment

In a short time, during the early phases of the COVID-19 pandemic outbreak, we managed to shift rapidly to use digital technologies and replace some of our daily operations with virtual modes. This shift happened so instantly and widely that it enables us to argue that the COVID-19 became a valid reason to boost some of the gradual and ongoing transitions towards faster transformations. In this study, we use gray literature to delve into arguments around the boost for digitization, digitalization, and systems thinking in the development of the built environment. This is mostly discussed from the influence of COVID-19 on some of the existing practices or the business-as-usual of the built environment sector. From technological advancement to technology use, these arguments are put forward to discuss what is likely to be the major driver of technological adoption and the shifting paradigms that are yet to be revealed. The study concludes that the current push towards new directions and development pathways are likely to be widely accepted in a shorter time. The findings of this brief study feed into existing arguments on transformative pathways due to the COVID-19 pandemic.

An Approximated Voxel Approach for the Identification and Modelling of Ligand-Binding Sites

Most protein-ligand interactions take place on surfaces and include but not limited to factors such as chemical composition, hydrophobicity, electronegavitiy and shape complementarity. Past studies showed that protein-protein interactions occur on comparatively fiat regions whereas protein-ligand bindings involve crevices. In the search for such sites various approaches have been designed and developed each of which is algorithmically unique. The use of grid units or voxels has been demonstrated in early studies with relatively good results obtained. We present here an approximated approach comprising of the use of voxels and computer vision methods in the search for ligand-binding areas. Each test protein is modelled and analysed in 2D with all corresponding residues graphically presented for successfully identified sites. The study was carried out on 2 sets of proteins： FK506-bound proteins and heme-bound proteins with promising results obtained for all test cases.

The Myth of the High-Efficiency External-Combustion Stirling Engine

The reported discrepancy between theory and experiment for external combustion Stirling engines is explained by the addition of thermal resistance of the combustion gasses to the standard Carnot model. In these cases, the Stirling engine ideal efficiency is not as is normally reported equal to the Carnot cycle efficiency but is significantly lower. A new equation for ideal Stirling engine efficiency when the heat is obtained through external combustion without pre-heating the air, is presented and results for various fuels tabulated. The results show that petrol and diesel, internal combustion engines (Otto cycle) have a higher ideal efficiency than the Stirling engine. When comparing thermoacoustic engines heated by wood, efficiency should not be quoted as a percentage of the Carnot efficiency, but against a figure 48% lower than Carnot. The effect is not seen with electrically heated rigs, solar or nuclear fission heated engines.

Effects of Surface Charges on the Seawater Desalination Using Functionalized Graphene

In this paper, we investigate the selection rule for desalinating seawater using functionalized graphene sheet as a semi-permissible membrane. Both the applied mathematical modeling and MD simulations will be used to determine the acceptance conditions for water molecule or sodium ion permeating into the functionalized graphene. Both the Lennard-Jones potential and Coulomb forces are considered by taking into accounts the major molecular and ionic interactions between molecules, ions and functionalized graphene sheet. The continuous approximation will then be used to coarse grain most significant molecular and ionic interactions so that the multi-body problems could be simplified into several two-body problems and the 3D motions are reduced into degenerated 1D motion. Our mathematical model and simulations show that the negatively charged graphene always accepts sodium ions and water;however the permeability of water molecules and sodium ions becomes very sensitive to the presence of positive charges on the graphene.

The Analysis of Global Warming Patterns from 1970s to 2010s

While global warming is only one part of climate change effects, it poses the highest risk to our habitats and ecologies. It is alarming that global warming has heightened in multiple locations and is intensified since the early 1970s. Since then, there are certain global warming patterns that could guide us with an overview of what mitigation and adaptation strategies should be developed in the future decades. There are certain regions affected more than another, and there are certain patterns with adverse effects on regions, sub-regions, and even continents. This study provides an insightful analysis of recent global warming patterns, those that are affecting us the most with regional climate change of different types, upsurge in frequency and intensity of natural disasters, and drastic impacts on our ecosystems around the world. By analysing the global warming patterns of these last four decades, this research study sheds light on where these patterns are coming from, how they are developing, and what are their impacts. This study is conducted through grey literature and analysis of the recorded global warming data publicly available by the NASA-GISS data centre for global temperature. This brief—but comprehensive—analysis helps us to have a better understanding of what comes next for global warming impacts, and how we should ultimately react. The study contributes to the field by discovering three key points analysed based on available data and literature on recorded global temperature, including: differences between north and south hemispheres, specific patterns due to ocean surface temperature increase, and recent impacts on particular regions. The study concludes with the importance of global scale analysis to have a more realistic understanding of the global warming patterns and their impacts on all living habitats.

A Critical Analysis of Group Work in Chinese University EFL Classes

In the past few years,group activities have been warmly welcomed by EFL(English as a foreign language)classes in Chi-na,but few studies have discussed it from a critical perspective.Thus,this study explores from students’experiences what and whythe strengths and weaknesses of group work in actual contexts appear.The findings reveal that Chinese learners regard group workas an effective interactive activity for language,personal,and emotional development.However,the possible pitfalls,such as pseu-dogroups,unequal participation,groupthink,L1(first language)influence may prevent learners from obtaining the benefits of CL(collaborative learning).Finally,some suggestions are given,with the purpose of creating a more suitable facilitative EFL classroomenvironment for future Chinese EFL teaching and learning.

The Effects of Fe₂O₃and B₂O₃on the Glass Structural, Thermal, <i>in Vitro</i>Degradation Properties of Phosphate Based Glasses

Currently, phosphate based glasses have been potential future biomaterial for medical application due to excellent cytocompatibility and fully bioresorbability. In this study, phosphate based glass system with composition of 48P2O5-12B2O3-(25-X)MgO-14CaO-1Na2O-(X)Fe2O3 (X = 6, 8, 10) and 45P2O5-(Y)B2O3-(32-Y)MgO-14CaO-1Na2O-8Fe2O3 (Y = 12, 15, 20), was prepared via a melting quenching process. The effect of replacing MgO with Fe2O3 and B2O3 on the structural, thermal, degradation properties of phosphate based glass was investigated. Fourier Transform Infrared (FTIR) spectroscopy and Raman spectroscopy analysis confirmed the polymerisation of phosphate based glass network with addition of Fe2O3, thus the processing window was observed to increase whilst the dissolution rate was reduced, attributed to the formation of Fe-O-P cross-link. As the effect on the glass structure stability was demonstrated by both B2O3 and MgO, the nonlinear variation of thermal stability and degradation behaviour was observed for glass system with substitution of MgO by B2O3. However, due to the lower dissolution rate of glass system when compared to the biocompatible phosphate based glass in preliminary study, the expected cytocompatibility could be confirmed in the downstream activities.

Study on synergistic leaching of potassium and phosphorus from potassium feldspar and solid waste phosphogypsum via coupling reactions

To achieve the resource utilization of solid waste phosphogypsum(PG)and tackle the problem of utilizing potassium feldspar(PF),a coupled synergistic process between PG and PF is proposed in this paper.The study investigates the features of P and F in PG,and explores the decomposition of PF using hydrofluoric acid(HF)in the sulfuric acid system for K leaching and leaching of P and F in PG.The impact factors such as sulfuric acid concentration,reaction temperature,reaction time,material ratio(PG/PF),liquid–solid ratio,PF particle size,and PF calcination temperature on the leaching of P and K is systematically investigated in this paper.The results show that under optimal conditions,the leaching rate of K and P reach more than 93%and 96%,respectively.Kinetics study using shrinking core model(SCM)indicates two significant stages with internal diffusion predominantly controlling the leaching of K.The apparent activation energies of these two stages are 11.92 kJ·mol^(-1)and 11.55 kJ·mol^(-1),respectively.

Performance of pulsed plasma thruster at low discharge energy

As the size of satellites scales down, low-power and compact propulsion systems such as the pulsed plasma thruster(PPT) are needed for stabilizing these miniature satellites in orbit. Most PPT systems are operated at 2 J or more of discharge energy. In this work, the performance of a PPT with a side-fed, tongue-flared electrode configuration operated within a lower discharge energy range of 0.5-2.5 J has been investigated. Ablation and charring of the polytetrafluoroethylene propellant surface were analyzed through field-effect scanning electron microscopy imaging and energy-dispersive X-ray spectroscopy. When the discharge energy fell below 2 J, inconsistencies occurred in the specific impulse and the thrust efficiency due to the measurement of the low mass bit. At energy ≥2 J, the performance parameters are compared with other PPT systems of similar configuration and discussed in depth.

Numerical Simulation of Electroosmotic Flow near Earthworm Surface

The electroosmotic flow near an earthworm surface is simulated numerically to further understand the anti soil adhesion mechanism of earthworm. A lattice Poisson method is employed to solve electric potential and charge .distributiorts in the electric double layer along the earthworm surface. The external electric field is obtained by solving a Laplace equation. The electroosmotic flow controlled by the Navier-Stokes equations with external body force is simulated by the lattice Boltzmann method. A benchmark test shows that accurate electric potential distributions can be obtained by the LPM. The simulation shows that the moving vortices, which probably contribute to anti soil adhesion, are formed near earthworm body surface by the nonuniform and variational electrical force.