Biotransfer of heavy metals along a soil-plant-insect-chicken food chain:Field study

The accumulation and transfer of Pb,Zn,Cu,and Cd along a soil-plant-insect-chicken food chain at contaminated sites were investigated.The study site nearing the Pb/Zn mine had been contaminated by heavy metals severely.Cadmium and Pb concentrations steadily declined with increasing trophic level（p 〈 0.01）,but concentrations of Zn and Cu slightly increased from plant to insect larva（p 〉 0.05）.The concentrations of heavy metals were the highest in chicken muscle,with lower values in liver and blood.The bioaccumulation of Pb was observed in chicken livers.The eliminations of Pb,Zn,Cu,and Cd via insect and chicken feces avoid metal bioaccumulation in insect and chicken body.These results suggest that the accumulation of heavy metals in specific animal organ of tissues could not be neglected,although transfer of metals to chicken from plant and insect was limited.

Beach Profiles Characteristics Along Giao Thuy and Hai Hau Coasts,Vietnam:A Field Study

Giao Thuy and Hai Hau coasts are located in Nam Dinh province, Vietnam, with a total coastline of 54.42 km in length. The sea-dike system has been seriously damaged and there have been many dike breaches which caused floods and losses. This situation is considered of a general representative for coastal area in the northern part of Vietnam. A variety of studies have shown that the gradient in the longshore sediment transport rate and the offshore fine sediment lost are the main mechanisms causing the beach erosion. This study presents a field investigation of the beach profiles at Giao Thuy and Hai Hau beaches. Three types of empirical functions for the equilibrium beach profile are applied and compared with the observations. Results show that all observed beach profiles can be described by a single function. However, one specific equilibrium profile equation is not sufficient to assess all beach profiles. In Section 1 of Giao Thuy and Section 3 of Hai Thinh beaches, beach profiles are consistent with the logarithmic function, while the exponential function fits well in Section 2. This difference is explained with respect to coastal morphology, sediment characteristics and hydrodynamic conditions which vary in site. An analysis of the validity of the beach profile functions is recommended for the numerical modeling and engineering designs in this area.

Field study on thermal comfort of naturally ventilated residences in southwest China

Kunming,a city in southwest China,has a climate that is different from most of the other places in the world because of its unique geographical characteristics.Due to its temperate climate,most of the residential buildings in this region are naturally ventilated.Accordingly,a winter thermal comfort study was conducted in Kunming to reveal the thermal response of residents.Indoor and outdoor environmental parameters were measured,and participants were investigated about their clothing,thermal sensations,thermal preferences,and thermal acceptance using online questionnaires.Data from 162 valid questionnaires were collected in the survey.Although the climate is referred to as“mild”,the survey showed that the indoor temperature during winter was lower than the typical comfort range.Nevertheless,the participants responded that most of them felt neutral and comfortable.The neutral temperature of participants living in Kunming was determined to be 16.96℃.The acceptable thermal sensation vote(TSV)range of the residents is-0.72 to 1.52.The acceptable indoor air temperature range is 15.03℃ to 19.55℃,and the optimum indoor air temperature is 17.2℃.According to this study,the existing thermal comfort evaluation models can hardly predict residents’thermal responses in Kunming well.

Numerical study on three-dimensional flow field of continuously rotating detonation in a toroidal chamber

Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry. The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature. The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted. Owing to the unconfined character of detonation wavelet, a deficit of detonation parameters was observed. Due to the effects of wall geometries, the strength of the outside detonation front is stronger than that of the inside portion. The detonation thus propagates with a constant circular velocity. Numerical simulation also shows three-dimensional rotating detonation structures, which display specific feature of the detonation- shock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity. It is believed that the present study could give an insight into the interest- ing properties of the continuously rotating detonation, and is thus beneficial to the design of continuous detonation propulsion systems.

Elastocaloric Effect in PbTiO3 Thin Films with 180°Domain Structure:A Phase Field Study

The elastocalorie effect of PbTiO3 thin films with 180° domain structure is studied using the phase field method. The influence of external stress σ33, misfit strain μm and domain wall energy on the adiabatic temperature change （ △ Tσ） at room temperature are carried out. The calculation results indicate that ｜△Tσ｜ increases as ｜σ33｜ or ｜μm｜ increases. The largest △ Tσ wlue of--7.81（ is obtained at σ33 = 2 GPa and Um =-0.02. Furthermore, the domain switching behaviors under different gradient coeffcients are different, and finally affect the elastocaloric effect in PTO thin films. These results could provide a guide to choose the substrate and the preparation process in experiments.

Feasibility Study on Welding Structure of the HT-7U Toroidal Field Coil Case

The Toroidal Field (TF) coil case of the HT-7U superconducting tokamak device is made of austenitic stainless steel 316LN and is designed to operate at cryogenic temperature (4 K). 316LN can retain high strength and fracture toughness at 4 K. Feasibility study on technical process of welding has been experimentally considered as a hopeful joint method for suppression of post-welding deformation and reduction of over-heating. Meanwhile the final range of stress intensity and the stress intensity factor (K) for pre-cracks of welding structure have been determined by using J-integral. These related results are optimistic and have shown that there's no problem in strength and fracture toughness at the vicinity of the pre-crack tip. This paper introduces the welding structure of TF coil case in detail.

Study on a new grain-cash cropping pattern in paddy field

We studied a new grain-cash cropping pattern composed of "barley/watermelon + waize-rice", comparing with "barley / watermelon-rice" (CKI), "watermelon-rice", (CK2). The experiment was conducted in CNRRI’s field for 3 yr, employing completely randomized design with three replications, and each plot occupied 207 m~2. The soil in the experiment field contained: N, 2.48 g. kg, quick effective P 4 mg. kg, and quick effective K 53 mg·kg. The varieties tested were Zhemai 2 (barley), Zhemi 1 (watermelon), Suyu 1 (maize), and Shanyou 63 (hybrid rice).

Grouting theories and technologies for the reinforcement of fractured rocks surrounding deep roadways

Grouting is an effective method to improve the integrity and stability of fractured rocks that surround deep roadways.After years of research and practice,various theories and a complete set of grouting technologies for deep roadways with fractured rocks have been developed and are widely applied in Chinese coal mining production.This paper systematically summarizes and analyzes the research results concerning the theory,design,materials,processes,and equipment for the grouting and reinforcement of fractured rocks surrounding deep roadways.Specifically,in terms of grouting methods,pregrouting,groutingwhile-excavation,and postgrouting methods are explored;in terms of grouting theory,backfill grouting,compaction grouting,infiltration grouting,and fracture grouting theories are studied.In addition,this paper also studies grouting borehole arrangement,water-cement ratio,grouting pressure,grouting volume,grout diffusion radius,and other grouting parameters and their determination methods.On this basis,this paper explores the physical and mechanical properties of organic and organic-inorganic composite grouting materials,and assess grouting reinforcement quality testing methods and instruments.Taken as the field cases,the application of pregrouting in front of heading faces,groutingwhile-excavation,and postgrouting in the Kouzidong coal mine are then introduced,and the effects of the grouting reinforcements are evaluated.This paper proposes a development direction for grouting technology based on problems existing in the grouting reinforcement of fractured rocks surrounding deep roadways.

Application of statistical analysis of sample size:How many occupant responses are required for an indoor environmental quality(IEQ)field study

Determining required sample size is one of the critical pathways to reproducible,reliable and robust results in human-related studies.This paper aims to answer a fundamental but often overlooked question:what sample size is required in surveys of occupant responses to indoor environmental quality(IEQ).The statistical models are introduced in order to promote determining required sample size for various types of data analysis methods commonly used in IEQ field studies.The Monte Carlo simulations are performed to verify the statistical methods and to illustrate the impact of sample size on the study accuracy and reliability.Several examples are presented to illustrate how to determine the value of the parameters in the statistical models based on previous similar research or existing databases.The required sample size including“worst”and“optimal”cases in each condition is obtained by this method and references.It is indicated that 385 is a“worst case”sample size to be adequate for a subgroup analysis,while if the researcher has an estimate of the study design and outcome,the“optimal case”sample size can potentially be reduced.When the required sample size is not achievable,the uncertainty in the result can properly interpret via a confidence interval.It is hoped that this paper would fill in the gap between statistical analysis of sample size and IEQ field research,and it can provide a useful reference for researchers when planning their own studies.

The influence of different functional areas on customers’thermal comfort-A Field study in shopping complexes of North China

Shopping complexes are widely built for their convenience and multiple functions.However,their complex func-tional areas,result in significantly different thermal environments and various customers’thermal perception.To explain the influence of functional related parameters on the thermal perception of customers in shopping com-plexes,we selected two typical functional related parameters,including customers’thermal expectation level of indoor environment in their current area and the area where the customer was ten minutes before taking the sur-vey.851 valid questionnaires were obtained in two typical shopping complexes during July.Customers’thermal neutral temperature,thermal preference temperature and thermal comfort temperature range were calculated in different functional areas.Customers’thermal expectation level was quantified by using expectancy factor.The results showed that customers’thermal expectation level in entertainment areas was the highest,followed by food courts,retail areas,and transition spaces.Customers’thermal expectation level would influence their thermal neutral temperature and thermal sensitivity.Customers with different thermal experience differed sig-nificantly in their thermal sensation voting(p<0.01).The highest thermal sensitivity,about 0.41/°C,was found in customers moving from high-temperature areas to low-temperature areas.These findings help to clarify how functional related parameters affect the thermal comfort of customers and provide the guidance for designing the indoor temperature in shopping complexes.

Analysis and numerical simulation of indoor thermal environments in some university classrooms

In order to study the indoor thermal environments in university classrooms in Tianjin,a field study and a questionnaire survey for a main teaching building are carried out.First,the thermal sensations of participants in the typical classrooms are studied by 180 questionnaires.Then,based on the measured data,the temperature changes in the classrooms during a year are simulated by the DeST software.The results show that the indoor thermal environments in the northern classrooms on the first floor are better than those in other classrooms.And the measurement results accord with the simulation results.These results can be used as a reference for the study of the indoor thermal environments in other seasons.

Internal field study of 21700 battery based on long-life embedded wireless temperature sensor

The safety of lithium-ion batteries is an essential concern where instant and accurate temperature sensing is critical.It is generally desired to put sensors inside batteries for instant sensing.However,the transmission of internal measurement outside batteries without interfering their normal state is a non-trivial task due to the harsh electrochemical environment,the particular packaging structures and the intrinsic electromagnetic shielding problems of batteries.In this work,a novel in-situ temperature sensing framework is proposed by incorporating temperature sensors with a novel signal transmission solution.The signal transmission solution uses a self-designed integrated-circuit which modulates the internal measurements outside battery via its positive pole without package breaking.Extensive experimental results validate the noninterference properties of the proposed framework.Our proposed in-situ temperature measurement by the self-designed signal modulation solution has a promising potential for in-situ battery health monitoring and thus promoting the development of smart batteries.

Deformation characteristics and reinforcement technology for entry subjected to mining-induced stresses

The entry at Zhangcun coal mine in Lu＇an coal mining area in Shanxi Province suffered from severe mining-induced stresses with the heading face driven oppositely to an adjacent working face. In this paper, the characteristics of deformation and failure of the entry were investigated in terms of the tempo-spatial relations between heading and working faces through field study and numerical modeling. The three-dimensional （3D） finite difference models were built to investigate stresses, displacements and damages in the surrounding rocks of the entry and the working face. The field study includes selection of reinforcing methods and materials, design parameters, and determination of cable prestress. The monitoring data of entry deformation and stress along the cables during every stage were presented. The state of the reinforced entry was evaluated based on the monitoring data. The results demonstrate that before the heading face of the entry crosses the adjacent working face, the influence of advanced abutment pressure caused by adjacent working face upon the entry is not significant. After they cross each other, however, the lateral abutment pressure will have an evident impact on the entry. The displacement rate of the entry will be greatly increased and reaches a certain value within a certain distance between the heading face and the working face. Then, it will increase again with the presence of secondary mining-induced pressure on the entry when the present working face advances. The fully-grouted cable with short length, high strength and high prestress is an effective way to reinforce the entry suffering from severe mining-induced stresses, which greatly reduces the displacement and failure possibility of the entry. Finally, the principles and recommendations for reinforcing design of entries suffering from severe mining-induced stresses were proposed according to field study, numerical modeling and experiences from other coal mines. Problems encountered in field study and suggestions for reinforcement were also discussed.

Simulation study of the superharmonic field generated from a phase array transducer

Ultrasound imaging is the most widely used noninvasive medical imaging modality. Its latest elite concept is Superharmonic Imaging which is the most talked-about future of medical diagnostic ultrasound. In this paper, the computational and analytical study for superharmonic field generation from phased array transducer of 16 × 16 elements is presented. For this, the model preferred, includes the calculation for diffraction effect in frequency domain and nonlinear effect in time domain. The attenuation is included along with the diffraction in frequency domain as well. The comparative analysis of superharmonic field is also carried out with simulated fundamental and second harmonic fields by the same model. Similarly, the comparison with the results from the literature is also reported.

Study of the second harmonic sound field from a circular piston source and the influence in the nonlinearity parameter tomography

In the nonlinearity parameter B/A tomography using the second harmonic wav, it is very important to analyze the ultrasonic field of the transducer, especially the generation of the second harmonic wave in the nearfield. In this paper, the theoretical study and experimental measurements of the second harmoinc pressure field from a circular piston source are performed.And the effect on the nonlinearity parameter tomograaphy is discussed. The results will be used to decrease the error of reconstruction in nonlinearity parameter tomography and bring the ultrasoinc diagnosis a step forward

Extreme Adaptation to Extreme Environments in Hot Dry, Hot Sub-humid and Hot Humid Climates in Mexico

The paper discusses the results of a field study carried out in four cities in Mexico： Hermosillo, Mexicali, Merida and Colima, during the warmest seasons of 2006-2007. The survey is according to the adaptive approach of thermal comfort. The cities＇ climates are hot dry, hot sub-humid and hot humid. The respondents were inhabitants of low cost housings without air conditioning. The research was performed during warm seasons and according to ISO 10551. The measurements were processed by the common method of linear regression and also by alternative methods, useful for asymmetric climates. Individuals declared comfort at very high temperatures, either high or low humidity, therefore, the resulting neutral temperatures are higher than 30 ℃, except in Colima （28.8 ℃）. The upper limits of comfort ranges achieved temperatures up to 35 ℃. The results suggest how great is the capacity of humans to adapt to conditions as extreme as those measured in the study.

AN EXPERIMENTAL STUDY ON THE FLOW FIELDS OF THE WEST LAKE BY ELECTRO-HYDRODYNAMIC ANALOGUE METHOD

Electro hydrodynamic analogue (EHA) method is applied to study the flow fields in the West Lake. It gives out a satisfactory result on water velocities and discharges of the bridge openings.

Cyclist Warning Systems: Design and Evaluation

Cyclists belong to the group of vulnerable road users and, thus, need particular protection in road traffic. One way to enhance cyclists’ safety is to use urban data (e.g., infrastructure data, accident statistics) to inform cyclists about potentially dangerous areas, allowing them to better adjust to the situation and elevate their self-protection. However, the question is how to inform cyclists about such dangerous areas. In this paper, we present the results of two field studies, investigating two wearables (headphones vs. smart glasses) and different signal options to inform cyclists about dangerous areas. Study participants were cycling along a predefined track and could experience the different wearables and signals. The main aim of the studies was to find out how cyclists perceive and experience the different approaches. Participants’ impressions were captured with questionnaires and interviews. Our results show a clear preference of the headphones over the smart glasses and signaling with intermittent audio while being in the dangerous area. However, we also found that participants’ acceptance of the approach was influenced by the additional perceived benefit the respective wearable would have in daily life. Using a wearable solely to be warned, although this would increase safety, was less acceptable. We discuss the implications of these findings for the design of cyclist warning systems.

A numerical study of sound field radiated by the flow around a circular cylinder

The Von-Karman vortex street flow behind a circular cylinder is successfully solved at Re= 100 for incompressible N- S equations in the form of stream function and vorticity. The method adopted here involves ADI - BGE schemes, a recent treatment of body boundary conditions and a new acceptable perturbation model. The solutions of the flow field obtained here are better than previous numerical ones and agree with the experimental data closer. Therefore, it can be used to study sound field numerically. The Curie equation is directly and numerically solved to analyze the distribution of sound sources and the characteristics of their radiated sound field at Re= 100 and to compare with the solution from the theory of vortex sound. It is shown that this method is successful.