bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of the behaviour of charged particles in electrical relay devices
Authors: Iida Masami , Koshimura Katsuaki , Kaneko Masahiro , Saeki Masato
Published: October 2019

This paper presents the results of analytical and experimental studies on the motion of a charged foreign object in an electrical relay. In the numerical approach, the motion of the lower and upper electrodes was solved by the finite element method. The colliding force between the foreign object and the electrodes was calculated by Hertzian contact theory. The electric field strength in the electrical relay was solved by the finite difference method. In the experimental approach, a spherical particle with a radius of 0.097mm made of polystyrene divinylbenzene was used as the foreign object. The validity of the analytical method was examined by comparing its results with the experimental results. It was shown that the motion of the particle is considerably affected by the electrostatic force.
Electrostatic agglomeration of fly ash particles for hybrid gas cleaning devices.
Authors: Sobczyk A T , Jaworek A , Marchewicz A , Krupa A , Czech T , Sliwiński Ł
Published: October 2019

The paper presents experimental results of the investigation of agglomeration of PM2.5 fly ash particles with larger particles in an electrostatic agglomerator. SEM micrographs of the obtained agglomerates shown that a single particle of the size of 10-20 μm can collect more than 20-50 PM2.5 particles in this type of agglomerator. The experiments were carried out in a semi-industrial scale channel of a cross section of about 600 mm height and 1100 mm width. The agglomerator can be used as a particle precharger in a hybrid system or as the first stage in a two-stage electrostatic precipitator, in order to increase their total collection efficiency.
Energy released by brush discharges from the fabric with conductive fibres
Authors: Ryszard Kacprzyk , Justyna Król , Adam Pelesz
Published: October 2019

Fabrics containing regularly spread conductive fibres introduced into their structure may storage an electric charge, what results in a characteristic surface potential distribution. The brush, electrostatic discharges may occur when the grounded conductive object approaches to the charged fabric surface. A simplified, charged fabric-grounded object model is proposed. A metal sphere as the conductive object and a synthetic fabric with conductive yarn (forming regular cells) are considered. The analytical model allows to connect the energy W
rel, that can be released during the discharge, with geometry of the fabric-object system. The model has led to the power type relation between the energy W
rel and the cell diameter of a.
Ignition risks associated with migratory antistatic liners at the point of use
Authors: Newlands C , Pavey I , Shepherdson S , Azizi W
Published: October 2019

Dissipative plastics are often used to reduce risks of static ignition sources in explosive atmospheres. Migratory agents which diffuse to the surface can aid dissipation. The agent attracts ambient moisture to the surface thus decreasing the electrical resistance. In tests it has been found that surface resistance of migratory liners can take around 24 hours to become dissipative. This brings into question whether conditioning periods recommended for surface resistance tests could be masking the ignition risk of materials. Surface resistance, transferred charge and gas probe ignition tests have been carried out to investigate the ignition likelihood further. Rubbing tests indicated that a protective lubricating film formed at around 1 hour that could prevent charge transfer events but subsequent rubbing removed the film leading to charge transfer events. Liner filling tests were set up similar to IEC 61340-4-4. This testing recorded charge transfer events of over 60 nC for all liners even after 24 hours exposure. Liner filling tests with the gas ignition probe produced ignitions with standard insulating liners (no migratory agent) but produced no ignitions or measurable charge transfers for migratory liners. A question remains over the use of charge transfer values to evaluate ignition risks for migratory static dissipative materials and more guidance is sought to help industry manage these risks.
Improved mathematical model of particle trajectories in multimodal electrostatic separators
Authors: Maammar Mohamed , Zeghloul Thami , Aksa Wessim , Medles Karim , Benabderrahmane Ahlem , Renoux Pascal , Dascalescu Lucian
Published: October 2019

The multimodal electrostatic separator has been designed to facilitate the feasibility assessment of corona-, tribo-, or purely-electrostatic processes of selective sorting of the constituents of granular mixtures. The versatility of the separator has imposed the development of an equally-agile simulation program for modelling the particle behaviour in each of the operational configurations of the machine. Thus, the paper discusses the numerical models that describe the various specific physical phenomena: corona-charging at the surface of the belt conveyor; induction charging of the conductive particles in contact with the grounded electrode; impact of particles with the rotating-roll high-voltage electrode. An example of conductive and insulating particles trajectories computation is given. The simulated results are compared with the experimental observations.
Atmospheric Potential Gradient Measurements from a Rooftop in Bangkok
Authors: Matthews J C , Wright M D , Navasumrit P , Ruchirawat M , Shallcross D E
Published: October 2019

Atmospheric potential gradient measurements at 1 Hz (averaged to 1 minute samples) were taken on the roof of a 6th floor building, approximately 100 m from a busy toll road in Lak Si, northern Bangkok. The measurement period covered the transition from hot season into rainy season. The heavy monsoon rains and heavy traffic can both be significant disruptors of the fair weather atmospheric potential gradient. Heavy traffic increased potential gradient due to aerosol loading, while rain storms increased the magnitude, but also changed the sign of the field due to charge processes within clouds. Increasing relative humidity led to a decrease in potential gradient, implying a lack of hygroscopic growth. Cross correlations of aerosol number in different size fractions showed that aerosols with a D50 value of 155 nm had the strongest correlation. A strong diurnal signal is present in frequency domain analysis of potential gradient.
Study of electrohydrodynamic phenomena in high temperature high pressure nitrogen
Authors: Bologa A , Paur H P , Woletz K , Stapf D
Published: October 2019

The study of corona discharge current-voltage characteristics (CVCs) in high temperature high pressure (HTHP) gases is an important step in development of compact HTHP electrostatic equipment. The scope of the current work was the study of corona discharge CVCs in HTHP nitrogen. Corona discharge ionizer was installed inside of a HTHP casing. Ionizer included star-shaped high voltage electrodes installed inside of a grounded tube electrode. The grounded electrode could be heated. Tests were carried out at various gas pressure and grounded electrode temperatures. The CVC-direct and CVC-indirect characteristics were measured for positive and negative polarity of applied voltage. For the same values of applied voltage, current for negative corona was higher than for positive one. The increase of gas pressure stabilized corona discharge and increased corona onset voltage. Operation of the ionizer at CVC-indirect ensured stable corona discharge. Corona discharge CVCs have shown hysteresis loop which area depended on gas pressure and temperature.
Time Resolved Measurement of Dielectric Particles Velocity on Standing Wave Electric Conveyor using PTV Technique
Authors: Zouaghi Ayyoub , Zouzou Noureddine , Braud Patrick
Published: October 2019

The interaction between micro-sized dielectric particles and standing wave electric field is investigated experimentally in this paper. The particles are deposited on a conveyor made of a series of copper electrodes on a dielectric surface and moved by an electric field. The standing wave electric field is generated by applying 2-phase voltage signals to the electrodes. Particles motion is recorded using high speed camera, and then a Particles Tracking Velocimetry (PTV) based post-processing is carried out in order to track each particle and evaluate its velocity. The main results indicate that the particles move toward both directions perpendicular to the electrodes close to the surface and their velocity increases. Some of them can reach the synchronism velocity equivalent to that of the electric wave. However, most of the particles cannot reach this velocity because of the contribution of adhesion and drag forces.
Theory of anomalous dielectric relaxation
Authors: Byrne D J , Coffey W T , Kalmykov Yu P , Titov S V
Published: October 2019

Anomalous dielectric relaxation in a double-well potential is reviewed showing that it explains the dielectric spectrum of CH2Cl2 decalin glass.
Bond-Graph Input-State-Output Port-Hamiltonian Formulation of Memristive Networks for emulation of Josephson Junction Circuits
Authors: Al-Mashhadani Israa Badr Nasser , Hadjiloucas Sillas
Published: October 2019

A bond graph Input-State-Output Port-Hamiltonian formulation of memristive networks for Josephson junction circuits in state space is presented. The methodology has applications to the modeling of SQUIDs and other non-linear transducers and enables the formulation of input-output models of complex components embedded in non-linear networks.
Potentialities of flexoelectric effect in soft polymer films for electromechanical applications
Authors: Guiffard Benoit , Saadeh Maria , Frère Pierre , Seveno Raynald , El-Gibari Mohammed , Sghaier Tessnim , Merupo V I , Kassiba Adi
Published: October 2019

Among the transduction mechanisms of interest for sensing and/or actuation applications at nano/micro scale, the piezoelectric effect has been widely exploited owing to the solid state nature of piezoelectrics, the large ability of specific classes of materials for the mechanical-to-electrical energy conversion and easy integration. However, every piezoelectric (also generally ferroelectric) presents well-known intrinsic drawbacks such as required poling step and related aging. In contrast, uniquely flexoelectric materials do not suffer from these disadvantages because flexoelectricity, a universal effect in all dielectric solids defined as the electrical polarization induced by a strain gradient, does not imply preliminary electric field-induced macroscopic polarization. Besides, strain gradient may be easily obtained by bending plate or cantilever-shaped structure and in this case it is nothing but the local curvature of the flexible system. Thus, as strain gradient (curvature) inversely scales with both elastic stiffness and thickness, this study will focus on the evaluation of the potentialities of flexoelectric effect in soft polymer films for electromechanical applications, with an emphasis on the thickness influence. In this way, analytical results combined to experimentally obtained effective flexoelectric coefficients for some typical polymer classes may provide guidelines for the development of soft and low frequency flexoelectric mechanical transducers.
NORM, a Health concern to Personnel exposed to Formation Drill Cuttings – Regulation issue in Nigeria
Authors: Okoro E E , Sanni S E , Emetere E M
Published: October 2019

During the drilling operations, formation rocks or shales drilled are removed from the wellbore as drill cuttings. These cuttings are real-time representative of the formation being drilled at that section of the wellbore, and it represents the formation of compositions and properties. Regulations for most oil well developments stipulate that the methods used for managing drill cuttings are dependent on the nature and type of drilling mud system used for the drilling operation. When the formation with these relatively high NORM contents is drilled using the drilling mud, these NORM traces are transported to the surface as drill cuttings; thus, exposing the personnel to health dangers and the immediate environment. The short and long-term health effects of NORM exposure include skin burns, harmful tissues reactions, increase the risk of lung cancer, mutation of somatic cells and leukemia. DPR has some standards and guidelines established to effectively police and regulate E&P industry activities in Nigeria. These guidelines and standards also take into consideration, the need for advanced pollution control strategies and technological treatments. However, the presence and harmful consequences of NORM in these drill cuttings are not considered in the current form of these regulations and guidelines. This study proposes the inclusion of NORM as a means of updating the already established guidelines and regulations for handling and treating these drill cuttings because they constitute the majority of the waste and toxic materials generated during drilling operations.
Importance of Rural Biomass Post-Harvest Waste – An Overview
Authors: Emmanuel Okoro Emeka , Samuel Sanni E. , Moses Emetere E.
Published: October 2019

This study rather than focus on food security examines the potential in utilizing Post-Harvest Waste (P-HW) materials and their benefits to the immediate rural communities where lignocellulose waste are found in abundance. It was observed that researchers have proposed a lot of unique approaches to managing solid waste generation; with emphasis on perfect waste collection and disposal, but these approaches are very expensive considering the tight budgeting expenses Nigeria is faced with. This study shows that some rural communities experience huge post-harvest organic wastes from their farms and the cost of these losses has been estimated, which then forms a good spot to start the implementation process for this initiative. The research highlights the overview benefits of adopting microbial and pyrolysis approach in converting the lignocellulosic aspect of these waste to economically viable products that will have a direct positive impact on the immediate community. This study proposed a modified fast pyrolysis approach in the conversion process to reduce the production of pyrolytic gas and optimize the production of biochar and pyroligneous acid. Adopting these approaches will reduce the amount of carbon emitted into the atmosphere when burning these waste and produce bio-products instead of synthesized chemical products that have health implications.
Influence of nanoparticles deposition on surface roughness and heat transfer characteristics of nanofluids – A review
Authors: Ogbonnaya Mercy , Ajayi Oluseyi O. , Waheed M.A , Oyedepo Sunday O. , Popoola A.P.I. , Popoola O.M.
Published: October 2019

The inherent low thermal conductivity of working fluids used in transferring heat from energy system makes the performance of the system less efficient. The introduction of nanoparticles into the working fluid enhances the thermal conductivity of the fluid, thereby improving the overall performance of the energy system. Deposition of nanoparticles on the heat transfer surface of the heat exchanger occurs and this affects the mechanism of bubble formation, wettability, surface roughness of the heating surface and the overall heat transfer coefficient. In this review, the use of nanofluid showed improvement in the critical heat transfer flux (CHF) of the heat transfer fluid while the deposition of nanoparticles on the heater surface enhanced the wettability for pool boiling but caused deterioration in the heat transfer. The influence of nanoparticles deposition on surface characteristics and heat transfer coefficient during single and two phase flows in flow boiling needs to be further investigated.
Review Of Heat Transfer Enhancement In Energy Conversion Systems; Nanotechnology
Authors: Kelvin Efemwenkiekie U. , Opemipo Atiba E. , Sunday Oyedepo O.
Published: October 2019

Different heat transfer fluids with very high thermal stability are highly desirable for heat exchangers. Inadequate understanding on the basic principle of nanofluid flow, unsatisfactory experimental data on nanofluid heat transfer and general context for heat transfer correlation is yet to be established. The work under focus will be on highlighting working principles, problems hindering practical application of unconventional heat exchangers devices, and the various means of utilizing nanotechnology in improved efficiency. The study investigates experiments on heat exchangers in the last decade, the gap in knowledge and future applications of nanotechnology in improving heat transfer. This review summarizes, the significant advances of various nanotechnology in heat transfer application of recent energy conversion system.
Protective Effect of Cajanus cajan in Hepatotoxic Rats
Authors: Evbakhavbokun  , Winifred O. , E.J. Emeka Iweala
Published: October 2019

Hepatotoxicity results from overload of chemicals and drugs including N-Nitrosodiethylamine (NDEA), a nitrosamine found in smoke, meat and food products. This study examined the hepatoprotective potential of Cajanus cajan in male Wistar rats. Hepatotoxicity was induced by administration of NDEA at 200mg/kg while Cajanus cajan was administered at 200mg/kg, 400mg/kg and 800mg/kg for 28 days. Body weight, liver weight and markers of hepatotoxicity including Alanine aminotransferase (ALT), Aspartate aminotransferase (AST) and Albumin (ALB) were evaluated. NDEA treated group showed a marginal increase in body weight and a significant (p < 0.05) increase in liver weight. The Cajanus cajan treated groups showed a significant (p < 0.05) increase and decrease respectively in body and liver weights. NDEA treated group significantly (P<0.05) increased ALT and AST and significantly reduced ALB. Cajanus cajan significantly (P<0.05) decreased ALT and AST and significantly (P<0.05) elevated ALB. The results indicate that Cajanus cajan ameliorates NDEA-induced hepatotoxicity.
Performance enhancement using appropriate mass charge of R600a in a developed domestic refrigerator
Authors: Banjo Solomon O. , Bolaji Bukola O. , Ajayi Oluseyi O. , Olufemi Babalola P. , Osagie Ibhadode , Onokwai Anthony O.
Published: October 2019

This paper presents performance analysis of a domestic refrigeration system using R600a as refrigerant. Investigation was conducted experimentally to select an appropriate refrigerant mass charge for the system and to compute the cooling system performance characteristics under ambient temperature of 29°C. The choice of the hydrocarbon refrigerant (R600a) became so imperative due to notable influence of chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) on global warming and ozone depletion. UNFCCC and Montreal Protocol regulation have banned the use of halogenated refrigerants in cooling and heating systems. The paper reveals that the power consumed by the system using mass charge of 15 g refrigerant was reduced by 9.3 and 10.9% compared with the 10 and 25 g refrigerant mass charges respectively. In addition, the results show that the coefficient of performance (COP) of the refrigeration system while working with 15 g is 24.7 and 20.2% higher than when the system worked with 10 and 25 g refrigerants mass charge respectively. More so, the system attained an evaporator air temperature of -12 °C in 2 hours, which makes 15 g charge refrigerant appropriate for the running of the developed system that has a volume capacity of 68 liters.
The Impact of Traffic Gridlock on Values of Residential Properties in Apapa, Lagos Nigeria
Authors: Iroham C O , Okubanjo T , Joshua O , Okagbue H I , Emetere M E , Akinjare O A , Peter J N , Akinwale O M
Published: October 2019

Traffic gridlock has been a concern in research particularly in determining its effect on property values. Resultant findings have either been a negative or positive impact. For the case of Apapa in Lagos State which is the focus of this present study, traffic gridlock has been an experience of over ten years, hence the need to discover its impact on various property value types as against the collective findings in most previous research. Student-T test of significance at a 95% level of confidence was adopted with results derived for all property types of the calculated T result far outweighing that of the stipulated Tabulated T result of 1.645. These findings for all property types indicate that the increase in property values for various property types have not been distorted by the traffic gridlock and as such investors in residential properties in the study area will always make their profit notwithstanding the gridlock. The researchers hereby advocated further research in determining the choice of residency in Apapa notwithstanding the traffic gridlock.
Mapping of Uranium-238 Deposit and its Contribution to Indoor Radon Gas in Ota, Ogun State, Nigeria
Authors: Adewoyin O. O. , Omeje M. , Onumejor C. A. , Adagunodo T. A. , Ndubuisi A. , Nwaluka V. O. , Akinpelu A. , Joel E. S.
Published: October 2019

In the present study, the distribution of uranium-238 was mapped from the background radiation of the area of study in order to determine its contribution to the concentration of indoor radon. The background radiation was studied using the handheld gamma spectrometer (RS 125) while the indoor radon concentration was measured with a Durridge RAD7 instrument. The results obtained showed variation in the distribution of 238U, 232Th and 40K in the study area with values ranging between 17.9 ± 0.3 and 58.05 ± 0.3, 2848 ± 10541 ± 0.8 and 3.25 ± 0.2 and 11.48 Bq/kg respectively. Furthermore, the indoor radon concentration was determined for the office on the ground floor, the result obtained was noted to be between 20 and 160 Bqm−3 which is far higher than the result obtained for the office on the first floor which is BDL-19 Bqm−3. In each cases, the results are lower than the international recommended safe limit of 200 Bqm−3. Therefore, it can be concluded that the background radiation from the soil in the premises and under the building contributes to the high concentration of indoor radiation in the office.
Board Expertise and Sustainability Reporting in Listed Banks in Nigeria
Authors: Umukoro O E , Uwuigbe O R , Uwuigbe U , Adegboye A , Ajetunmobi O , Nwaze C
Published: October 2019

Despite the growing evidence on the determinants of sustainability reporting, there exist limited and inconclusive studies on the impact of board expertise on sustainability reporting. This study investigates the influence of environmentally sensitive, certified or educated board members on the disclosure of sustainability report. Based on the static panel data regression estimators for 10 Nigerian Deposit Money Banks over the period of 2014-2016, the study revealed that highly educated directors have an altogether constructive influence on the sustainability report disclosure while controlling for corporate administration and firm-level qualities. In addition, we find that the executive and non-executive directors have low experience in environmental issues resulting in an insignificant effect on the disclosure of sustainability reporting. This paper suggests that firms should allow more directors with environmental background, who have a lower motivation to boost transient returns since they are likely to influence environmental performance.
Short review on the prospects of human biogas utilization in Nigeria
Authors: Emetere M.E. , Adesina T. A.
Published: October 2019

Energy challenge in Nigeria is really disturbing due to many factors that borders on the inability of the national grid to meet-up with the huge energy demands in the most populated country in Africa. About 85% industries and domestic users patronize fossil fuel generators. This development had increased the air pollution load over the country. In this research, fourteen years dataset from the Nigeria Metrological Agency (NIMET) was used to simulate the energy accruable from solar energy in Nigeria. The study is poised to enhance higher patronage of solar technology in the research site.
Solar energy estimation and generation in Ibadan Nigeria
Authors: Emetere M.E. , Emetere J.M. , Diana E.
Published: October 2019

Energy challenge in Nigeria is really disturbing due to many factors that borders on the inability of the national grid to meet-up with the huge energy demands in the most populated country in Africa. About 85% industries and domestic users patronize fossil fuel generators. This development had increased the air pollution load over the country. In this research, fourteen years dataset from the Nigeria Metrological Agency (NIMET) was used to simulate the energy accruable from solar energy in Nigeria. The study is poised to enhance higher patronage of solar technology in the research site.
Review On Probiotics Potentials, Nutritional Composition Of Bambara Nut (Vigna Subterranea (L.) -An Underutilized LegumE
Authors: Nwinyi Obinna C , Umane Phoebe O
Published: October 2019

Bambara nut is one of the underutilized legumes. Conversely this underutilized legume could be utilized to solve the ravaging food security issues in sub-Saharan Africa owing to its balanced nutritive composition. Bambara nut limited use, is because of the antnutritional factors, hard to cook phenomenon and difficulty in dehulling. Because of high global demand on food security, there is an urgent need to review possible methods that could reduce the limiting factors to the widespread use of this crop and enunciate other benefits derivable from this legume. In this review, we appraised the nutritional composition of Bambara nut from different geographic locations, commonly associated bacteria species that predominate mostly during Bambara fermentation and their potential uses as probiotics. Expedient areas for further research were highlighted in this paper
Comparative Analysis of Biogas Produced from Cow Dung and Poultry Droppings
Authors: Diagi Evangeline A , Akinyemi Marvel L , Emetere Moses E , Ogunrinola Iyanuoluwa E , Ndubuisi Amanda O
Published: October 2019

This study involves a comparative analysis of two waste substrates; cow dung and poultry droppings. The purpose of this study was to ascertain which of the waste substrates produces a greater yield of biogas, their individual retention period as well as the percentage of the methane content in the gas generated. The study was divided into two experiments which comprised of a water displacement set up in a laboratory and one 30 L fixed dome digester for each waste substrate. In both experiments waste substrates were mixed with water in ratio 1:1 and operated at a mesophilic temperature condition. In the laboratory, the daily gas yield of the individual substrates in ml was obtained, it was observed that cow dung produced an average of 29.9 ml of biogas per day and the poultry waste produced 60.7 ml per day. A gas analysis was performed to obtain the gas profile of gas produced from the two substrates. As deduced from the analysis, cow dung had a methane and CO2 weight percentage of about 92 wt% and 6.68 wt% respectively, while poultry droppings had about 90 wt% methane and 6.56 wt% CO2.With the aid of a constructed mini gas stove, a flame test was performed, which gave off a blue flame. Hence, the two substrates are efficient for biogas production.
Air pollution Estimation Over Brikama
Authors: Emetere M.E. , Olawole O.C.
Published: October 2019

Recent reports on the air pollution over Brikama-Gambia by United Nations Environment Programme (UNEP) and the National Environment Agency (NEA) may be shocking. In this paper, fifteen years primary (aerosol optical depth) dataset was obtained from the Multi-angle Imaging Spectro-Radiometer (MISR). The secondary datasets were generated from the primary dataset to understand the short and long term effect of aerosol loading over Brikama. The dataset is important to help researcher understand the dynamics of the aerosol loadings in the area. It was discovered that the air pollution over Brikama is not seasonal and do not come from same source. It was observed that the pollution over Brikama is determined by the massisve influx and migration of human population.
A coupled excavation and rainfall-induced loess landslide in Liuwanjia Village,Yan’an China: Case study of Middle Pleistocene loess slopes
Authors: Fan Zhongjie , Meng Zhenjiang , Ren Hongyu , Peng Jianbing , Pei Xiangjun , Dong Linyao , Du Jun , Zhang Hongya
Published: October 2019

Loess Plateau is one of the natural test sites to carry out the research of hazards induced by human activities. The loess landslide at Liuwanjia, Yan’an City, Shaanxi Province of China was observed to occur after continuous excavation and rainfall. The Liuwanjia landslide was selected as a case study and then detailed field mapping, 3D laser scanning and laboratory tests were carried out to study the formation characteristics and mechanism of this type of landslide. Based on the analysis of field investigation, excavation was a direct causing factor and the rainwater was a significant influencing factor in the formation of the landslide. The unloading fissures caused by excavation were preferential paths for infiltration of rainwater. Soil compression in the slope induced by excavation and the infiltration of rainwater played an significant role in the formation of local failure. Finally, the formation mechanism of Liuwanjia landslide has been discussed.
Differences in carbonaceous aerosol of fine particles between haze and non-haze days, Beijing
Authors: Liu Qingyang
Published: October 2019

In order to illustrate the factors dominating haze events over Beijing occurred in January, 2013, ambient fine particulate matter (PM2.5, particles with aerodynamic diameter less than or equal to 2.5 μm) samples were collected from January 16 to 31, 2013 at an urban area of Beijing. Daily meteorological parameters including atmospheric pressure, temperature, wind speed, and relative humidity (RH) were recorded. Carbonaceous aerosols in PM2.5 including elemental carbon, organic carbon, PAHs, n-alkanes and levoglucosan were determined to compare the concentration differences between haze days and non-haze days. Associations between PM2.5 carbonaceous aerosols and meteorological parameters were examined. Significant increases of carbonaceous aerosols are found in haze days than those in non-haze days, indicating primary emission sources play a role in haze events occurred in January, 2013. Meteorological parameters do not correlate with carbonaceous aerosols, supporting the regional transport is not dominant factor controlling haze formations. Our results show the primary emissions and meteorological conditions co-contribute the haze formation in Beijing during the sampling period of January, 2013.
Holiday effect of sulfur dioxide concentration in Sanming City, Fujian Province
Authors: Liao Xiaoli , Jin Shaofei , Wu Yonghong , Liu Youwen
Published: October 2019

Sulfur dioxide (SO2) is a common air pollutant. Excessive SO2 can have adverse effects on human health. SO2 emissions are not only affected by industrial production, but also from people’s daily life. This study used the daily data of sulfur dioxide in Sanming City from 2015 to 2018 to analyze the holiday effect on the SO2 concentration in Sanming City. The results showed that the concentration of summer and autumn working days in Sanming City is greater than that of holidays; the concentration of holidays in spring and winter is higher than that of working days. The proportion of sulfur dioxide concentration in the Spring Festival holiday in the year of 2015-2017 is increasing year by year. This study reveals the holiday effect of sulfur dioxide concentration in Sanming City, which has important practical significance for controlling sulfur dioxide pollution in Sanming City and improving the quality of local atmospheric environment.
Analysis on the temperature results of thermal infrared remote sensing based on a ground platform
Authors: Yuan Xu , Meng Qinglin
Published: October 2019

Thermal infrared cameras have been widely used to measure temperature as a non-invasive measuring instrument recently. To assess the temperature results of thermal infrared remote sensing, we compared them with the temperature obtained by traditional contact temperature measuring method. A ground remote sensing platform was designed to obtain the thermal infrared temperature of the underlying surface. Meanwhile, the traditional contact method was used to obtain surface temperature synchronously. Afterward, the two kinds of temperature were compared and analyzed. Our results indicate that for the four kinds of underlying surface studied in this paper, the two kinds of temperature all have strong correlation. Furthermore, the mean temperature difference ranges between 0.46 °C and 1.79 °C. Moreover, no significant difference can be observed between the two kinds of the temperature of grassland, tile, and permeable brick when the evaluation is at the level of P = 0.001.
HCHs and DDTs in the Bohai Sea: Contamination, distribution and sources
Authors: Song Qiuyang , Luo Wei , Wu Guanghong
Published: October 2019

Concentrations, distributions, and potential sources of DDTs and HCHs in seawater, sediments, soils, and atmosphere were collected to review their pollution statuses in the Bohai Sea and its coastal areas. In comparison to various sediment and seawater quality standards, DDTs and HCHs in sediments and seawater were at low levels in the entire Bohai Sea and might not cause adverse biological effects. However, DDTs and HCHs levels in various sea areas were closely associated with local pesticides production and application as well as hydrodynamic. DDTs and HCHs showed an obvious spatial distribution pattern. High levels were found in the Bohai Bay, Haihe River and Yellow River estuary. DDTs and HCHs concentrations in river and estuary sediments were higher than sea sediments and a seaward decreasing trend was observed. Although HCHs and DDTs residues in the Bohai Sea primarily originated from river runoffs (pesticide factory wastewater, historical applications and residues of technical HCH and DDT, etc.), additional sources of lindane and dicofol existed. Runoff from the demolished old pesticide factories might be another source. Further researches are highly recommended on pollution hotpots of DDTs and HCHs and investigate their migration and transformation at sediment-water interface and pollution history from sediment depth profiles.
Study on economy of flue gas ultra-low emission in coal-fired power
Authors: Zhang Yang , Liu Qingsong , Wei Hongge , Du Zhen , Zhu Yue
Published: October 2019

Along with the rapid progress of flue gas ultra-low emission reconstruction in coal-fired power plants in recent years, flue gas pollutant control is markedly improved, but the economic efficiency of flue gas ultra-low emission was undervalued. Given the present situation of flue gas ultra-low emission in coal-fired power plants, several typical problems about economic efficiency have been analyzed and discussed, including coordinated optimization operation, emissions target control, energy efficiency management on the basis of extensive and thorough investigations. Relevant guidance and countermeasures are proposed to provide further reference for subsequent operation and maintenance of power generation enterprises.
Landscape applications of rainwater resources in urban green space: A case study of green space reconstruction along Riverside Street in Suzhou
Authors: Zhao Wenjing , Ma Jianwu
Published: October 2019

The environmental problems exposed by the process of urbanization have become increasingly serious. At present, China has realized that rainwater is an important and valuable resource. Many cities have successively carried out the mode of rainwater resource utilization.This paper attempts to explore the design of rainwater management into landscape design, transforming from a single engineering technology level to a sustainable ecological level. From the source control, route transmission, terminal storage and storage, the three systems summarize the design of rainwater resources landscape application. Taking urban green space as the research object, and taking the reconstruction of the riverside green space in Suzhou as an example, the advantages and existing problems are analyzed. The feasibility of rainwater management is qualitatively analyzed and the rainwater runoff is quantitatively analyzed. The two measures of surface improvement and rainwater storage are used to explain how to integrate these design methods into specific cases, aiming for the future. Rainwater management in urban green space provides successful experience of others to go by.
Analysis and evaluation of heavy metal pollution in agricultural soils in six cities of Hunan Province, China
Authors: Yu Yang , Sun Cong , Zhang Linlin , Xu Renji , Zhu Yuanyuan , Wu Guoping , Wei Fusheng
Published: October 2019

Environmental problems caused by the exploitation of mineral resources are worsening, especially the heavy metal pollution in soil. Food safety caused by heavy metal pollution in soil has become the focus of increasing attention.Sampling points were selected in Hunan Province. By sampling the soil and rice point by point, the total concentration and the concontration in rice were monitored. The results showed that the mean concentration of Cd, Cu, Hg, Pb and Zn were 1.31 mg/kg, 45.3 mg/kg, 0.61 mg/kg, 49.15 mg/kg and 133.3 mg/kg. The soils were contaminated in some parts of the 85 investigated sites in Hunan Province.Also, the analysis results showed that the average of PI (pollution index) descended in the order of Cd (2.58) > Hg (1.05) > Cu (0.52)> Zn (0.51)> Pb (0.41).The NIPI values of the research area were 28.59, belong to the high-level pollution, which mainly caused by Cd. The pollution ratio of soil samples were 100.0% in Zhuzhou-Xiangtan and Changning, 94.1%, 90.9% and 88.2% in Changde, Yiyang and Yongzhou. According to the potential ecological risk evaluation result, there was a medium level risk in the investigation area of Hunan and the potential ecological risk mainly caused by Cd.
Fine interpretation by using the VMD-based Instantaneous centroid estimation method for a marine carbonate gas reservoir
Authors: Xue Yajuan , Cao Junxing , Wang Xingjian
Published: October 2019

We apply the variational mode decomposition (VMD)-based instantaneous centroid estimation method for interpreting a 11-meters main gas-producing interval of the Longmenshan foreland basin, China. Five VMD-based instantaneous centroid slices are generated for fine interpretation. The results are evaluated by the measured well data. The application results show that the VMD-based instantaneous centroid estimation method targets the 11m main gas-producing interval very well. Field data application shows that the VMD-based instantaneous centroid estimation method can give a fine interpretation of hydrocarbon-related information with high-precision.
Experimental study on recharge capacity of a mixed well injection in Xi’an
Authors: Zhang Xuezhen , Huo Aidi , Wang Jucui
Published: October 2019

The over-exploitation of groundwater can be controlled and prevented by using mixed well to recharge groundwater. A seepage model of semi-confined aquifers was established for simulating recharge well in a cone of depression. Two mathematical expression formulas were proposed for estimating recharge capacity. To analyze the response of recharge capacity, stepwise injections were introduced. It can be pointed out that recharge capacity increases with that of injection flow; moreover, it tends to attenuate during steady injection, which is closely related to injection flow. An attenuation equation of recharge capacity was constructed finally. Recharge capacity was not related to injection mode. The results indicate that under similar conditions, recharge capacity of a mixed well was about one-third of pumping capacity. A minimum value of recharge capacity was maintained with constant injection. Mixed wells were used to recharge and recover groundwater from the cone of depression.
Evaluation of weathered crust reservoirs in buried hills in western uplift belt of JB block in Indonesia
Authors: Zhu Houqin , Li Zenghui , Hong Guoliang , Ma Yuxia , Bai Zhenhua
Published: October 2019

After nearly 20 years of exploration, the western uplift belt of the JB block is now at a high exploration level, and the buried hill has become another new exploration area besides lithologic traps. On the basis of the results of well logging of 17 wells, core of 6 wells and logging interpretation of 17 wells, the differences in the vertical texture features of the basement reservoir are fully considered. According to the differences of logging and seismic response characteristics of 500 km2 between weathered zone and the fractured zone, the colored inversion technique and spectral imaging technique combined with seismic attribute technology are used to predict the plane distribution of porous reservoir in weathered crust. The pre-stack elastic wave impedance inversion technique is preferred for oil-gas-bearing detection evaluation. The results show that the lithology of the B paleo-uplift is granite, and that of the P paleo-uplift is phyllite. The vertical zoning of the buried hill reservoir is obvious, which can be divided into weathered crust zone, fractured zone and tight zone from top to bottom. From the top of the weatheredzone to the fractured zone, the porosity becomes smaller gradually, and distributes in the shape of the discontinuous strips laterally. The planar distribution of the pore-type reservoirs in the weathered zone is obviously controlled by the paleo-structure, and is in the shape of strips and flakiness with obvious zoning characteristics. The porous reservoir is relatively developed onthe crest of the paleo-structure, and the weathered crust reservoir quality of B uplift is superior to that of the P uplifts. Hydrocarbon mainly distributes in the high parts of the two paleo-structures in the shape of strip and flakiness. The results provide a scientific basis for the follow-up drilling decision-making.
Evolution of Cr, Cu, Mn, and Zn during the composting process of chicken manure and their integrated potential ecological risk assessment
Authors: Fan Liangqian , Miao Jiaxin , Yang Jingrui , Zhao Xiaoqing , Xie Maozhu , Shi Weijuan , Cai Jie , Ding Weike
Published: October 2019

The aim of this study was to ascertain the evolution of Cr, Cu, Mn, and Zn during the composting process of chicken manure and their integrated potential ecological risk. This study detected the total amounts of Cr, Cu, Mn, and Zn in 4 samples collected at four different stages in the composting workshop of an intensive chicken farm in Chengdu, China. Furthermore, the chemical fractionation of the four heavy metals was analyzed by the BCR (European Community Bureau of Reference) three-step sequential extraction procedure for each sample. At last, the integrated potential ecological risk of Cr, Cu, Mn, and Zn in the compost at four different stages was evaluated by the procedure of potential ecological risk assessment based on its results of chemical fractionation of Cr, Cu, Zn, and Mn. During the composting process, the total amounts of Cr, Cu, Zn and Mn presented an increasing trend, significantly. Nevertheless, the residual fraction (Res-F) percentage of Cr, Zn, and Cu increased, and the acid extractable fraction (Aci-F) percentage of Mn decreased. The value of integrated potential ecological risk of the four heavy metals in the final product was 9.91. These results indicated the integrated potential ecological risk of the four heavy metals is low. This study provided a support on the promotion and utilization of compost for the intensive chicken farms in China.
Experimental study on oxidation mechanism of pyrite under acidic conditions
Authors: Shi Hong , Zhang Yongbo , Liu Qiang
Published: October 2019

In this study, pyrite samples from the Yankan Coal Mine near the Shandi River in Yangquan City were studied in an oxidation dissolution experiment. Pyrite was studied at different solid-liquid ratios (1:100, 1:50, and 1:20), and the oxygen concentration used was equal to the value in the ambient environment, about 20.95% of the air volume. The pH, oxidation-reduction potential (Eh), and soluble salt concentration (EC), total iron concentration, and SO4
2− concentration in the solution at different reaction times were measured with respect to time. The oxidation reaction rate of pyrite was calculated using the SO4
2− concentration and the factors influencing the oxidation rate at different conditions were discussed. The experimental results showed that, after pyrite was oxidized and dissolved at solid-liquid ratios of 1:20, pyrite decrease from acid generation of the SO4
2−formation, then the pH of the solution increased, at solid-liquid ratios of 1:100, 1:50, and 1:20, the overall Eh and EC values decreased. No matter what solid-liquid ratio is adopted for the reaction, the Fe2+ concentration is higher than Fe3+ concentration, and the Fe2+ and total iron concentration all increase with the increase of solid-liquid ratio, while Fe3+ gradually increases, reaching a trend of relatively stable and slowly decreasing. The average apparent release rate of Fe was proportional to the different solid-liquid ratios. The oxidation reaction rate of pyrite under acidic conditions was directly related to the concentration of reactants, and a faster oxidation rate was observed at higher concentrations due to the larger reaction contact area.
Study on pre-splitting blasting technology of hard roof face
Authors: Liu Huaifu , Xu Zunyu
Published: October 2019

In order to solve the problems of hard roof caving and overhanging area in 220116 working face of Xinji No.2 Coal Mine, deep-hole pre-splitting blasting overburden technology is adopted to destroy the integrity of roof in advance so as to make it collapse as soon as possible, reduce the apparent strength of rock pressure of initial weighting, and slow down the destructive effect of initial weighting on support. The numerical simulation shows that the first collapse step of the basic roof is obviously reduced after the forced roof caving, which greatly reduces the impact disaster caused by large area roof weighting, is conducive to the stability of the support and roof safety management, and is of great significance to the safety production of the working face.
A Comparative Analysis of Different Turbulence Models for Simulating Complex Turbulent Separated Flows over Cubic Geometries
Authors: Praliyev Nurgeldy , Sarsen Aydarkhan , Kaishubayeva Nazira , Zhao Yong , Fok Sai Cheong , Teh Soo Lee
Published: October 2019

This study is aimed to compare the performance of four Reynolds Averaged Navier Stokes (RANS) turbulence models in simulating complex flow over two- and three-dimensional (2D and 3D) cubic geometries using experimental measurements for model validation. The four turbulence models were k-Epsilon (k-ε), k-Omega (k-ω), Shear Stress Transport (SST) and BSL Reynolds Stress (RSM) models. The model validation was performed by comparative analysis with the experimental values of pressure coefficient around the cubic geometries. It was found that the SST and BSL RSM models performed better than the others in capturing the complex separated flows and strong shear in the boundary layer. The good agreement with empirical data can be attributed to the inclusion of transport effects of turbulence and the anisotropic nature in the formulations of the models.