An Analysis of Net Berth Productivity in the Handling Operations with Dry Bulk Cargoes in a Seaport

Productivity at the berth is one from the group of port productivity measures which is closely tied to ship turnaround times.Net berth productivity is value of productivity related to the operational time at the berth.Based on the facts identified from available literature about minor share of researches related to the net berth productivity in the handling operations with dry bulk cargoes in a seaport,it was decided to take this port productivity metrics as an object of a research.After a detailed analysis of different categories of the net berth productivity in the handling operations with dry bulks,key groups of influential factors which determine values of the net berth productivity are identified and systematized.Some principal elements related to improving net berth productivity are taken into consideration,too.Concrete results shown in this paper are related to the Dry Bulk Cargo Terminal in the Port of Bar(Montenegro).

Self-adapting extraction of matrix mineral bulk modulus and verification of fluid substitution

Gassmann＇s equations are commonly used for predicting seismic wave velocity in rock physics research.However the input matrix mineral bulk modulus parameters are not accurate,which greatly influences the prediction reliability.In this paper,combining the Russell fluid factor with the Gassman-Biot-Geertsma equation and introducing the dry-rock Poisson＇s ratio,we propose an effective matrix mineral bulk modulus extraction method.This method can adaptively invert the equivalent matrix mineral bulk modulus to apply the Gassmann equation to fluid substitution of complex carbonate reservoirs and increase the fluid prediction reliability.The verification of the actual material fluid substitution also shows that this method is reliable,efficient,and adaptable.

Mass and heat transfer mechanism in wood during radio frequency/vacuum drying and numerical analysis

The mass and heat transfer mechanisms during radio frequency/vacuum （RF/V） drying of square-edged timber were analyzed and discussed in detail, and a new one-dimensional mathematical model to describe the transport phenomena of mass and heat during continuous RF/V drying was derived from conservation equations based on the mass and heat transfer theory of porous materials The new model provided a relatively fast and efficient way to simulate vacuum drying behavior assisted by dielectric heating. Its advantages compared with the conventional models include： （1） Each independent vari- able has a separate control equation and is solved inde- pendently by converting the partial differential equation into a difference equation with the finite volume method; （2） The calculated data from different parts of the specimen can be displayed in the evolution curves, and the change law of the,parameters can be better described. After analyzing the calculated results, most of the important phenomena observed during RF/V drying were adequately described by this model.

Convective drying of wood chips:Accelerating coupled DEM-CFD simulations with parametrized reduced single particle models

The simulation of industry-scale reactive bulks is challenging due to the complex interaction between fluid and particles.The particles in the bulk and their interaction with the fluid flow can be described by combined Discrete Element Method-Computational Fluid Dynamics(DEM-CFD)models.However,the computational cost of the Finite Volume(FV)methods deployed in these models can become prohibi-tively expensive,especially for high inner-particle resolution.Single particle Reduced Models(RMs)can be used to achieve both fast and accurate descriptions of the processes in each particle.As an example of bulk systems comprising heat and mass transfer,we compared FV and RM simulations for the drying of wood chips in a bulk reactor.A manifold-based nonlinear interpolation was applied to resolve changing boundary conditions for the RM.Our simulations showed that RMs provide accurate values for the thermodynamic state variables of the particles.Furthermore,the time required for the bulk simulation was reduced by 67%with the RMs.It is evident that simulations with high inner-particle resolution can be accelerated by RMs if manifold-based nonlinear interpolation is used to address changing boundary conditions.

花生自然风干种子油酸、亚油酸和棕榈酸含量的近红外分析模型构建

近红外光谱分析技术在作物育种中得到广泛应用。提高花生种子品质近红外分析技术,不断改进花生种子主要脂肪酸组分近红外模型,对深入开展花生品质育种具有重要意义。利用不同来源、不同种皮颜色的大粒型和小粒型材料,构建了花生自然风干种子油酸、亚油酸和棕榈酸含量的近红外定量分析模型。经优化,最佳光谱预处理方法均为"一阶导数+矢量归一化法",油酸含量谱区范围为8717.1～5446.3cm-(1厘米波数),维数为9,模型的决定系数(R2)为89.16,均方差(RMSECV)为2.62;花生种子亚油酸含量谱区范围为9666～5785.7cm-1,维数为9,模型R2为90.85,RMSECV为2.00;花生种子棕榈酸含量谱区范围为8717.1～5446.3cm-1,维数为8,模型R2为79.21,RMSECV为0.525。该模型可用于花生品质育种。

半本体法合成醇溶性聚丙烯酸酯及在快干型涂料中的应用研究

以丙烯酸丁酯、甲基丙烯酸甲酯、苯乙烯、丙烯酸羟乙酯为单体,以过氧化二苯甲酰为引发剂,工业酒精为溶剂,采用半本体法合成醇溶性的丙烯酸酯聚合物。研究了引发剂种类、引发剂浓度、功能单体用量、软硬单体配比、加料方式对聚合物性能和相应涂料防腐性能的影响。结果表明:选用过氧化二苯甲酰为引发剂,且用量为2%、苯乙烯用量为5%、极性单体用量为10%、m(丙烯酸丁酯):m(甲基丙烯酸甲酯)=1:1时,以半本体法合成的聚合物配制的涂膜在25℃,相对湿度为90%的条件下,表干时间小于10 min,实干小于40 min,综合防腐性能好。

花生自然风干种子芥酸含量近红外分析模型构建

采集67份自然风干花生种子的近红外光谱,并进行芥酸含量色谱测定。采用交叉检验,构建了多粒自然风干花生种子样品芥酸含量的近红外定量分析模型。经优化,最佳光谱预处理方法为"消除常量偏移法",芥酸含量谱区范围为4 242.8～11 980.2 cm^(-1),维数为10,模型的决定系数(R^2)为80.08,交叉检验根均方差(RMSECV)为0.0238。此模型可以很好地预测花生种子芥酸含量,为花生脂肪酸遗传改良提供快速的选择手段。

Enhanced atmospheric phosphorus deposition in Asia and Europe in the past two decades

There is increasing interest in understanding atmospheric phosphorus(P)deposition and its impacts on plant pro-ductivity and carbon sinks in ecosystems.However,the global pattern of P deposition remains poorly understood,primarily due to the sparseness of data in Asia.In this study,the authors compiled 396 published observations of atmospheric P deposition from 1959 to 2020 on the global scale.The results gave a geometric mean bulk P deposition value of 0.32 kg ha−1 yr−1,or a global P budget of 4.4 Tg yr−1.Compared with the period 1959-2000,the authors found an elevated P deposition in Europe and Asia during 2001-2020,likely due to the increas-ing agricultural emissions and fossil fuel combustion-related sources in addition to dust emissions.The findings highlight the need to quantify the impacts of elevated P deposition from anthropogenic emissions on long-term ecosystem development in the context of carbon neutrality and clean-air actions.

Effects of moisture content and dry bulk density on the thermal conductivity of compacted backfill soil

Soil backfilling and compaction are often involved in urban construction projects like the burying of power cables.The thermal conductance of backfill soil is therefore of great interest.To investigate the thermal conductivity variation of compacted backfill soil,10 typical soils sampled in Zhejiang Province of China with moisture contents of 0%–25%were fully compacted according to the Proctor compaction test method and then subjected to thermal conductivity measurement using the thermal probe method at 20℃.The particle size distribution and the chemical composition of the soil samples were characterized to analyze their effects on thermal conductivity.The results showed that the maximum thermal conductivity of fully compacted soils generally exceeds 1.9 W/(m·K)and is 20%–50%higher than that of uncompacted soils.With increasing moisture content,soil thermal conductivity and dry bulk density first increase and then remain unchanged or decrease slowly;the critical moisture content is greater than 20%in most cases.Overall,the critical moisture content of soils with large particle size is lower than that of those with small particle size.Quartz has the highest thermal conductivity in the soil solid phase,and the mass percentage of quartz for most soils in this study is more than 50%,while that for yellow soil is less than 30%,which leads to the thermal conductivity of the former being nearly twice as great as that of the latter in most circumstances.Based on regression analysis,with moisture content and dry bulk density as the independent parameters,the prediction formulae for the thermal conductivity of two categories of compacted backfill soils are proposed for practical applications.

Atmospheric deposition of inorganic nitrogen in a semi-arid grassland of Inner Mongolia, China

Due to increasing global demand for crop production and energy use, more and more reactive nitrogen（Nr） has been generated and emitted to the environment. As a result, global atmospheric nitrogen（N） deposition has tripled since the industrial revolution and the ecological environment and human health have been harmed. In this study, we measured dry and wet/bulk N deposition from July 2013 to December 2015 in a semi-arid grassland of Duolun County, Inner Mongolia, China. The samples of dry and wet/bulk N deposition were collected monthly with a DELTA（DEnuder for Long Term Atmospheric sampling） system and with Gradko passive samplers and a precipitation gauge. The measured results show that the annual mean concentrations of NH_3, NO_2, HNO_3, particulate NH_4~＋（pNH_4~＋） and particulate NO_3^-（pNO_3^-） in atmosphere were 2.33, 1.90, 0.18, 1.42 and 0.42 μg N/m3, respectively, and that the annual mean volume-weighted concentrations of NH_4~＋-N and NO_3^--N in precipitation were 2.71 and 1.99 mg N/L, respectively. The concentrations of Nr components（including NH_3, NO_2, HNO_3, p NH_4~＋, pNO_3^-, NH_4~＋-N and NO_3^--N） exhibited different seasonal variations. Specifically, NO_2 and HNO_3 exhibited higher concentrations in autumn than in summer, while the other Nr components（NH_3, pNH_4~＋, pNO_3^-, NH_4~＋-N and NO_3^--N） showed the highest values in summer. Based on measured concentrations of Nr components and their deposition velocities estimated using the GEOS-Chem global atmospheric chemical transport model, the calculated annual mean dry deposition fluxes were 3.17, 1.13, 0.63, 0.91 and 0.36 kg N/（hm^2·a） for NH_3, NO_2, HNO_3, p NH_4~＋ and pNO_3^-, respectively, and the calculated annual mean wet/bulk deposition fluxes were 5.37 and 3.15 kg N/（hm^2·a） for NH_4~＋-N and NO_3^--N, respectively. The estimated annual N deposition（including dry N deposition and wet/bulk N deposition） reached 14.7 kg N/（hm^2·a） in grassland of Duolun County, approaching to the upper limit of the N critical load（10–15 kg N/（hm^2·a））. Dry and wet/bulk deposition fluxes of all Nr components（with an exception of HNO_3） showed similar seasonal variations with the maximum deposition flux in summer and the minimum in winter. Reduced Nr components（e.g., gaseous NH_3 and p NH_4~＋ in atmosphere and NH_4~＋-N in precipitation） dominated the total N deposition at the sampling site（accounted for 64% of the total N deposition）, suggesting that the deposited atmospheric Nr mainly originated from agricultural activities. Considering the projected future increases in crop and livestock production in Inner Mongolia, the ecological and human risks to the negative effects of increased N deposition could be increased if no mitigation measures are taken.

An empirical analysis of freight rate and vessel price volatility transmission in global dry bulk shipping market

Global dry bulk shipping market is an important element of global economy and trade. Since newbuilding and secondhand vessels are often traded as assets and the freight rate is the key determinant of vessel price, it is important for shipping market participants to understand the market dynamics and price transmission mechanism over time to make suitable stra- tegic decisions. To address this issue, a mulfi-variate GARCH model was applied in this paper to explore the volatility spillover effects across the vessel markets （including newbuilding and secondhand vessel markets） and freight market. Specifically, the BEKK parameterizafion of the multi-variate GARCH model （BEKK GARCH） was proposed to capture the volatility transmission effect from the freight market, newbuilding and secondhand vessel markets in the global dry bulk shipping industry. Empirical results reveal that significant volatility transmission effects exist in each market sector, i.e. capesize, panamax, handymax and handysize. Besides, the market volatility transmission mechanism varies among different vessel types. Moreover, some bilateral effects are found in the dry bulk shipping market, showing that lagged variances could affect the current variance in a counterpart market, regardless of the volatility transmission. A simple ratio is proposed to guide investors optimizing their portfolio allocations. The findings in this paper could provide unique insights for investors to understand the market and hedge their portfolios well.

Soil Physical Properties and Grain Yield Influenced by Cover Crops and Crop Rotation

The crop yield is related to several factors, among these, soil tillage, soil compaction and crop rotation. This study aimed to evaluate the winter cover crops and crop rotation influence on soil physical properties and grain yield of dry beans, maize and soybean for two growing seasons. Three experiments were conducted, corresponding to dry beans, maize and soybean crops. It was used the randomized block design with three treatments and four replications consisted by 3 × 10 m plots. The treatments were: two cover crops systems and crop rotation in no-till, and the control, consisting of winter fallow and conventional tillage. The cover crop dry matter, soil physical properties and grain yield for dry beans, maize and soybean in the two growing seasons were evaluated. Crop rotation systems and cover crops showed a trend to increase maize and soybean yields. Crop rotation in no-till increases soil compaction in the superficial layer compared to conventional tillage, but does not reduce the dry beans, maize and soybean yields.

A brief introduction to recent applications of several sediment-analysis techniques in palaeolimnological studies-dry bulk density and water content, mineral magnetism, carbonate content, and content of total organic carbon,nitrogen content and carbon/nitrogen ratio

Determination of dry bulk density and water content measurement of magnetic susceptibility (x) and saturation isothermal remanent magnetization (SIRM), determination of carbonate content, and determination of total organic carbon (TOC) content nitrogen content (N%) and carbon/nitrogen (C/N) ratio are some of the techniques which have been widely applied to lacustrine-sediment analyses. The techniques,complemented by others, are usually useful for revealing characteristics of lacustrine-sediments and thus for postulating hydrological regimes in the lake and environmental conditions and human activity around it in palaeolimnological studies. A very brief review is presented on recent applications of these techniques in palaeolimnological work with English literatures published mainly since 1985 and focus given on interpretations of results of these analyses related to palaeoenvironmental reconstructions. Low dry bulk density and high water content often imply relatively warm and wet conditions. High X and SIRM are usually resulted from reduced dilutions in the lake and intensified erosions on its catchment. both of which can be in turn attributed to environmental changes. While variations in patterns of X and SIRM may give further insight on mineral magnetism and thus implications on environmental conditions. Increased carbonate content seems likely to associate to warm and dry conditions.Increased TOC content is virtually used as one of indicators of warm and wet conditions and variations in C/N ratio may hint variations in relative contributions of different sources, aquatic and terrestrial, to the total organic matter in lake sediments and hence to lake-level fluctuations and climate changes.

Microwave drying kinetics and quality characteristics of corn

In recent years,microwave(MW)drying has gained popularity as an alternative drying method for a wide variety of food and agricultural products because of increasing concerns over product quality and production costs.However,the determination of drying kinetics that accurately describes microwave drying characteristics is crucial for the optimization of operating parameters,performance improvement of the drying system and product quality.The objective of this study was to investigate the drying kinetics and the quality characteristics of corn kernels,especially the effects of different initial moisture contents(18.3%,26.3%,34.3%and 42.3%db),MW power levels(70,175 and 245 W)and exposure time(80 s and 120 s)on the drying kinetics,drying rate and various key quality parameters.The results indicated that the increased drying rate at higher power levels(P3,245 W)reduced the drying time considerably but increased stress crack index and reduced germination.In addition,it reduced bulk density,true density and thousand grain weight(TGW).The germination rate of corn was the highest at MW power level P1(70 W),with the lowest drying rate and observed to decrease with increase in initial moisture content.The reduction in exposure time decreased stress crack index and increased germination rate,bulk density and true density.The correlation analysis among drying rate,germination,stress-crack index(SCI),bulk density,true density and TGW showed that increasing drying rate could lead to an increase in SCI and decrease in germination,bulk density and true density.

冻干人用狂犬病疫苗原液纯度体积分子排阻高效液相色谱检测方法的建立及验证

目的 建立冻干人用狂犬病疫苗原液纯度的体积分子排阻高效液相色谱(size exclusion column-high performance liquid chromatography,SEC-HPLC)检测方法,并进行验证。方法 采用TSK-gel G6000PWXL色谱柱(7.8 mm×30 cm,13μm)进行测定,流动相为:0.1 mol/L PB缓冲液(pH 7.8);流速为:0.5 mL/min;检测波长为:280 nm;进样量为:20μL;柱温为:30℃。验证方法的系统适用性、专属性、精密性、耐用性,并确定检测限和定量限。采用建立的方法检测3批冻干人用狂犬病疫苗(Vero细胞)原液及1批冻干人用狂犬病疫苗(人二倍体细胞)原液的纯度。结果 参比品与两种基质制备的冻干人用狂犬病疫苗原液目的蛋白色谱峰的分离度均> 1.5,峰拖尾因子均<1.5;空白溶剂在目的蛋白出峰位置无吸收峰,不干扰测定;精密性验证中的保留时间和峰面积RSD均<2.0%;定量限为10μg/mL,检测限为4μg/mL;参比品在278、280、282 nm 3种不同检测波长下连续进样3次,保留时间和峰面积RSD均<2.0%。4批冻干人用狂犬病疫苗原液的纯度均> 97%。结论 建立的冻干人用狂犬病疫苗原液纯度SECHPLC检测方法具有良好的专属性、精密性及耐用性,为人用狂犬病疫苗的质量控制提供了可靠方法。

改性生土块材抗剪性能试验研究

为了改善传统生土材料的力学性能和耐久性能,对掺加一定比例水泥、石灰、砂子、麦秸秆等掺料的干燥改性生土试块进行直接剪切试验,得到改性生土试块的破坏形态、破坏过程、剪应力-剪切位移关系曲线、抗剪强度与垂直压力的关系曲线以及受剪极限承载力;对比分析掺加不同改性材料以及同种材料不同比例对生土块材的强度和变形性能的影响规律,研究各种掺料对生土块材性能产生影响的机理;设计专门用于研究生土块材抗剪性能的推剪试验,探索能正确反映生土结构中土体抗剪性能的试验方法。

Study of Soil-Water Characteristic Curve Using Microscopic Spherical Particle Model

When variations occur in the water content or dry bulk density of soil,the contact angle hysteresis will affect the soil-water characteristic curve(SWCC).The occurrence of the contact angle hysteresis can be divided into slipping and pinning.It is difficult to determine the effect of pinning existence on SWCC by tests.In this study,the effect of contact angle hysteresis on SWCC was analyzed either in the case of no variations in soil dry bulk density with changes in soil water content or no variations in soil water content with changes in soil dry bulk density.In both cases,soil particles were simplified to the spherical particle model.Based on the geometrically mechanic relationship between the particles and connecting liquid bridges,a physical model for predicting the SWCC was derived from the spherical particle model.Adjusting parameters made the model applicable to various soils,that is,the cohesive soil was considered as micron-sized spherical particles.Through the simulations on SWCC test data of sand,silt,clay,and swelling soil,it was confirmed that the physical model possessed good reliability and practicability.Finally,the analysis of rationality of contact angle was performed based on the basic assumptions of the model.

STUDY ON THE EOLIAN DUST FLUX OVER THE LOESS PLATEAU:AN EXAMPLE

The wind is a basic factor in the atmosphere subsystem in the Earth system, and an agent in transferring the mass and energy within the system. The grain size and mass flux of the eolian dust in the Neocene deep-sea sediments recorded the intensity of the atmospheric circulation and the aridity in the dust source area. The loess on the Loess Plateau, the dust accumulation after its origin, transportation, deposition, and reworked process, is

冻干人用狂犬病疫苗（Vero细胞）半成品SEC-HPLC左侧肩峰蛋白鉴定

目的对冻干人用狂犬病疫苗(Vero细胞)半成品SEC-HPLC左侧肩峰蛋白进行鉴定。方法将人血白蛋白(human serum albumin,HSA)和疫苗半成品分别进行SEC-HPLC分析,收集左侧肩峰后进行烷基化,并用胰酶酶解,产物进行nanoLC-MS/MS分析。结果HSA SEC-HPLC左侧肩峰成功鉴定6个蛋白,包括1个HSA和5个非HSA蛋白;疫苗半成品SEC-HPLC左侧肩峰成功鉴定3个蛋白,包括1个HSA和2个非HSA蛋白,它们均在HSA SEC左侧肩峰中被鉴定。结论冻干人用狂犬病疫苗(Vero细胞)半成品SEC-HPLC左侧肩峰蛋白来源于HSA。