Field Tests for Investigating the Extraction Rate of Piles Using a Vibratory Technique

Factors directly affecting the extraction rate of the piles pulled out by a vibratory pulling system are summarized and classified into five categories(excitation force,resistance,vibration amplitude,pile plumbness keeping,and slowing down at the later stage) from the mechanics and engineering practice.Field tests on steel sheet piles extracted by vibratory technique in different soil conditions are conducted to ascertain how these factors affect the extraction rate of a pile with regard to three major actors of vibratory pile pulling:the pile to be extracted,the selected pulling system,and the imposed soil conditions.The extraction rates of three different sheet pile types(having up to four different lengths) pulled out by two different vibratory pulling systems are documented.The piles with different lengths and types,pulled out with or without a clutch,have different extraction rates.The working parameters governing the vibratory hammer,such as excitation force and vibration amplitude,exert significant influences on the rate of pile extraction,especially in the early stages of up-lift process.The extraction rate of the piles driven in different soil conditions is uniform because different extraction resistances mainly refer to shaft friction.The properties of the pile-soil interface influence the extraction rate of the piles,and the extraction rate decreases with the time for which the piles have been buried in the earth.

Line-of-sight rates extraction of roll-pitch seeker under anti-infrared decoy state

In this paper,the method of extracting guidance information such as the line-of-sight(LOS)rates under the anti-infrared decoy state for the roll-pitch seeker is researched.Coordinate systems which are used to describe the angles transform are defined.The LOS angles reconstruction model of the roll-pitch seeker in inertial space is established.A Kalman filter model for extracting LOS rates of the roll-pitch seeker is proposed.In this model,the target performs constant acceleration(CA)model maneuvers.The error model of LOS rates extraction under infrared decoy state is established.Several existing methods of extracting LOS rates under anti-infrared decoy state are listed in this paper.Different from the existing methods,a novel method that uses extrapolated values of target accelerations as filter measurements is proposed to solve the guidance information extraction problem under the anti-infrared decoy state.Numerical simulations are conducted to verify the effectiveness of the proposed method under different target maneuvering models such as the CA model,the CA extended model and the singer model.The simulation results show that the proposed method of extracting guidance information such as LOS rates for the rollpitch seeker under the anti-infrared decoy state is effective.

Techniques and Technological Aspects of Palm Oil (Elaeis guineensis) Processing in Cameroon

Crude palm Oil (CPO) processing is very popular in African Countries. In Cameroon, various actors are involved ranging from agro-industrial complexes to traditional processing by smallholders who use very inefficient equipment and thus have low oil extraction rates. Small-scale processing by smallholders dates back to the early 1980s and has witnessed a lot of changes as a result of new actors in the sector, changing technologies and to an extent, government policies. This paper attempts a review of the origins and evolution of small-scale palm oil processing using intermediate technology, highlighting its importance to both the farmer and the national economy. An attempt is made to look into the future of this activity, with proposals for its consolidation.

Review of Research on Li-Ion Batteries Waste Management

Li-ion batteries (Libs) are a mature technology widely used for energy storage in various electronic devices. Nowadays, this technology has become a leading candidate for the portable electronics market and for electric vehicles due to its good performance. As a result, the demand for Libs containing critical metals, rare earth elements and precious metals is increasing day by day with the accelerated upgrades of consumer electronics, which promotes the supply risk of many mining resources. In addition, the problems associated with the production of end-of-life Lib are increasing on a global scale. Used Libs are e-waste containing significant levels of critical raw materials (such as Co, Li, Mn and Ni) along with harmful substances. Without proper management of Lib waste, these precious metals and toxic substances may end up in nature and cause environmental and public health problems. In order to preserve nature, ensure sustainable resource management and stimulate the circular economy, it has become crucial to properly manage and recycle end-of-life Li-ion batteries. By the way, conventional methods focusing on pyrometallurgical treatments combined with hydrometallurgical treatment are widely studied to recover design metals from Libs waste. It is in this context that we have conducted this bibliographic synthesis, focusing on the efficiency of the solvents employed and their competitiveness for a more environmentally friendly economic management. In this manuscript, recent leaching, solvent extraction, electrodeposition and precipitation strategies to recover precious metals from end-of-life Li-ion battery designs are reviewed and the evolution of these processes is discussed.

Revisiting Income Inequality in China from an Evolving Productivity Perspective

Income inequality in China has evolved substantially amid rising productivity since reform and opening up in the late 1970s.Based on the group decomposition equation for Gini coefficient,this paper estimates China’s inequality possibility frontier(IPF)and the inequality extraction rate(IER).Results indicate that:(i)From 1978 to 2017,China’s IPF continuously expanded amid improving productivity,and the maximum feasible Gini coefficient rose from 0.2281 to 0.8446.(ii)Meanwhile,China’s overall IER decreased from 123%to 55%.More specifically,China’s IER fell sharply over the period 1978-1980,stabilized in the period from the mid-1980s to 2012,and further declined after the 18th CPC National Congress in 2012.Currently,55%of China’s maximum feasible inequality has been converted into actual inequality.The correlation between inequality and productivity is recognized in academia but seldom explored in the literature.To fill this void,this paper empirically measures inequality in light of productivity development.Our research conclusions explain why yawning income gaps in China have been tolerated since reform and opening up,and offer empirical evidence for setting income distribution policies according to economic development in the new era.

A combined method using Lattice Boltzmann Method(LBM)and Finite Volume Method(FVM)to simulate geothermal reservoirs in Enhanced Geothermal System(EGS)

With the development of industrial activities,global warming has accelerated due to excessive emission of CO_(2).Enhanced Geothermal System(EGS)utilizes deep geothermal heat for power generation.Although porous medium theory is commonly employed to model geothermal reservoirs in EGS,Hot Dry Rock(HDR)presents a challenge as it consists of impermeable granite with zero porosity,potentially distorting the physical interpretation.To address this,the Lattice Boltzmann Method(LBM)is employed to simulate CO_(2)flow within geothermal reservoirs and the Finite Volume Method(FVM)to solve the energy conservation equation for temperature distribution.This combined method of LBM and FVM is imple-mented using MATLAB.The results showed that the Reynolds numbers(Re)of 3,000 and 8,000 lead to higher heat extraction rates from geothermal reservoirs.However,higher Re values may accelerate thermal breakthrough,posing challenges to EGS operation.Meanwhile,non-equilibrium of density in fractures becomes more pronounced during the system's life cycle,with non-Darcy's law becoming significant at Re values of 3,000 and 8,000.Density stratification due to buoyancy effects significantly impacts temperature distribution within geothermal reservoirs,with buoyancy effects at Re=100 under gravitational influence being noteworthy.Larger Re values(3,000 and 8,000)induce stronger forced convection,leading to more uniform density distribution.The addition of proppant negatively affects heat transfer performance in geothermal reservoirs,especially in single fractures.Practical engineering considerations should determine the quantity of proppant through detailed numerical simulations.

Optimization of xanthophylls extraction from Marigold extractum with supercritical CO_(2) by response surface methodology

In this work,xanthophylls were extracted from Marigold using supercritical CO_(2).A response surface experimental design was used to optimize operating conditions for extraction pressure(22-30 MPa),extraction temperature(50-60℃),CO_(2) flow rate(9-15 kg/h).The maximum concentration of xanthophyll in extracts was determined to be 35.8%by high performance liquid chromatography(HPLC),and optimum xanthophylls extraction was obtained at 55℃,26 MPa and 12 kg/h.The optimization results demonstrated that for xanthophylls extraction,all variables(temperature,pressure and CO_(2) flow rate)were to be the influential variables,with the statistical significant effect p-value was smaller than 0.05.