Strength criterion for crystalline rocks considering grain size effect and tensile-compressive strength ratio

The macroscopic mechanical properties of rocks are significantly influenced by their microstructure.As a material bonded by mineral grains,the grain morphology of crystalline rock is the primary factor influencing the strength.However,most strength criteria neglect the strength variations caused by different grain characteristics in rocks.Furthermore,the traditional linear criteria tend to overestimate tensile strength and exhibit apex singularity.To address these shortcomings,a piecewise strength criterion that considers the grain size effect has been proposed.A part of an ellipse was employed to construct the envelope of the tensive-shear region on the meridian plane,to accurately reproduce the low tensile-compressive strength ratio.Based on the analysis of experimental data,both linear and exponential modification functions that account for grain size effects were integrated into the proposed criterion.The corresponding finite element algorithm has been implemented.The accuracy and applicability of the proposed criterion were validated by comparing with the experimental data.

Effect of C/S Ratio on Morphology and Structure of Hydrothermally Synthesized Calcium Silicate Hydrate

The samples of the C-S-H series were synthesized by hydrothermal reaction of fumed silica, CaO and deionized water at initial C/S ratios between 1.0-1.7. Phase composition and structural and morphology characteristics of C-S-H samples were analyzed by XRD, IR and SEM. The experimental results showed that the d-spacing of （002）, （110） and （020） decreased, the d-spacing of （200） increased, and the d-spacing of （310） varied randomly, the polymerization of silica tetrahedra of C-S-H decreased, and morphology of C-S-H samples varied from sheet shapes to long reticular fibers as C/S ratio increased.

Influence of calcium content on solid ratio of inclusions in Ca-treated liquid steel

It has been found that Ca-treated liquid steel can be cast at a lower superheat. To ascertain the reason for the improved castability of Ca-treated liquid steel and to find the optimal range of calcium content, the behavior of calcium in liquid steel was studied in terms of the relationship between the calcium content and solid ratio of inclusions. The relationship between the calcium content and solid ratio of inclusions was obtained by means of the classification of nonmetallic inclusions in solid and liquid steels at casting temperature according to the Al2O3-CaO-SiO2 phase diagram. The optimum calcium content should be 17-23 ppm.

Does the long-term application of calcium superphosphate lead to an increase of the soil rare earth element contents？

In order to test whether the long-term application of calcium superphosphate leads to an increase of the soil rare earth element contents, superphosphate fertilized soils were sampled and compared with superphosphate-free soils. Spectrophlame inductively coupled argon plasma atomic emission spectrophotometer （ICP-AES） was applied to quantify the rare earth elements （REEs）. The total rare earth element contents in calcium superphosphate from Zhijin County, west part of Guizhou Province, China （produced by the sulphuric acid treatment of the apatites） are about 2.54 mg/g. Between 38 and 189 gREEs/hm^2 per year （available for plants, estimated by 2% citric acid） will be introduced into the soil solution when applying 320 kg superphosphate/hm^2 per year. The long-term application of the latter will increase the REE content by about 18% in the soil surface layer in these areas. A statistically significant increase of the content of the rare earths in some cultivated soils should not be neglected.

Photosynthetic efficiency, cell volume, and elemental stoichiometric ratios in Thalassirosira weissflogii under phosphorus limitation

Nutrient limitation is known to inhibit growth and metabolism and to alter elemental stoichiometric ratios in phytoplankton. In this study, physiological changes in Thalassirosira weissflogii were measured under different dissolved inorganic phosphate (DIP) regimes in semi-continuous cultures to revisit the utility of the Redfield ratio for assessing nutrient limitation. The results showed that cell size increased with decreasing DIP availability. In the P-depleted treatment (f/2-P) the cell size was 1.48 times larger than that in the P-limited (f/100) treatment and 2.67 times larger than that in the P-saturated treatment (f/2 and f/10). The fucoxanthin to chlorophyll a ratio (Fuco/chl a) was relatively stable (about 0.3) in P-saturated cultures and was 10 times higher than that in P-limited and P-depleted cultures. During the experimental period, the photosynthetic efficiency index, ?F/Fm′, was relatively stable at ~0.50 in the P-saturated cultures, but quickly declined with decreasing DIP availability. Although cellular P content showed a significant difference between the P-saturated culture (1.6 pg/cell) and the P-limited culture (0.7 pg/cell), the N/P ratio in T. weissflogii did not show a trend with DIP availability and fluctuated slightly around 25. Our results suggest that cell division in T. weissflogii is not strictly size-gated but is probably regulated by a biochemical, and hence, an elemental stoichiometric ratio threshold, and that deviation of the cellular N/P ratio from the Redfield ratio is not a reliable indicator of algal nutrient stress.

Role of calcium and other trace elements in the gastrointestinal physiology

Calcium is an essential ion in both marine and terrestrial organisms, where it plays a crucial role in processes ranging from the formation and maintenance of the skeleton to the regulation of neuronal function. The Ca^2＋ balance is maintained by three organ systems, including the gastrointestinal tract, bone and kidney. Since first being cloned in 1993 the Ca^2＋-sensing receptor has been expressed along the entire gastrointestinal tract, until now the exact function is only partly elucidated. As of this date it still remains to be determined if the Ca^2＋-sensing receptor is involved in calcium handling by the gastrointestinal tract. However, there are few studies showing physiological effects of the Ca^2＋-sensing receptor on gastric acid secretion and fluid transport in the colon. In addition, polyamines and amino acids have been shown to activate the Ca^2＋-sensing receptor and also act as allosteric modifiers to signal nutrient availability to intestinal epithelial cells. Activation of the colonic Ca^2＋-sensing receptor can abrogate cyclic nucleotide-mediated fluid secretion suggesting a role of the receptor in modifying secretory diarrheas like cholera. For many cell types changes in extracellular Ca^2＋ concentration can switch the cellular behavior from proliferation to terminal differentiation or quiescence. As cancer remains predominantly a disease of disordered balance between proliferation, termination and apoptosis, disruption in the function of the Ca^2＋-sensing receptor may contribute to the progression of neoplastic disease. Loss of the growth suppressing effects of elevated extracellular Ca^2＋ have been demonstrated in colon carcinoma, and have been correlated with changes in the level of CaSR expression.

Study on the packed volume and the void ratio of idealized human red blood cells using a ?nite-discrete element method

Numerical simulations are performed to examine the packing behavior of human red blood cells(RBCs). A combined ?nite-discrete element method(FDEM) is utilized, in which the RBCs are modeled as no-friction and no-adhesion solid bodies. The packed volume and the void ratio of a large number of randomly packed RBCs are clari?ed,and the effects of the RBC shape, the mesh size, the cell number, and the container size are investigated. The results show that the packed human RBCs with normal shape have a void ratio of 28.45%, which is slightly higher than that of the ?at or thick cells used in this study. Such information is bene?cial to the further understanding on the geometric features of human RBCs and the research on RBC simulations.

Effects of Copper-Zinc Alloy Doped with Rare Earth Elements on Crystal of Calcium Carbonate

A copper-zinc alloy doped with rare earth elements was prepared and the mechanism was demonstrated in a simulating boiler and circulating cooling water with rigidity 1 mmol·L-1. The polar curve and scale inhibiting ability of the alloy was tested by a corrosion measurement system and a scale inhibition evaluation system, respectively. Scale samples were characterized with SEM and XRD. It is found that the transfer of cations could be promoted by doping with proper rare earth elements, and the corrosion potentials descend by 25～126 mV. The results indicated that the copper-zinc alloy doped with rare earth elements has higher scale inhibiting ability of CaCO3. The growth of calcite was affected by zinc ions dissolved because of primary battery reaction, and the transition of calcium carbonate from aragonite to calcite was hampered resulting in the proportion of aragonite to calcite is changed from 1.7∶1 to 2.7∶1.

Ratios of Closely Related Elements in Soil and Their Implications

This paper has investigated the ratios of closely related elements such as Mn,Cr,V,Ni,Co,Cu,Pb,Cd,Ba,Sr,La and Ce in the major soils of China,and the factors affecting them,and explored their use as indicators in soil formation,material transport and environmental pollution.Results show that the effect of soil-forming processes on the ratios of closely related elements varied with different elements,and became greater in the sequence of Ce/La <V/Cr≈Ni/Co<Zn/Cu≈Zn/Pb<Zn/Cd<Mn/Cr<Ba/Sr.The magnitude of the variation in the ratios of closely related elements depended on the chemical properties of the elements themselves,on the one hand,and the parent material and climatic conditions on the other.The ratio of Ba/Sr showed a distinct zonality,decreasing gradually in the sequence:cool temperate zone acid soils>grassland soils>desert soils and increasing gradually from the semi-arid subhumid zone soils>the temperate zone neutral soils>the north subtropic zone soils>tropical and subtropical acid soils.

Use of Finite Element Analysis for the Prediction of Driver Fatality Ratio Based on Vehicle Intrusion Ratio in Head-On Collisions

To estimate the aggressivity of vehicles in frontal crashes, national highway traffic safety administration (NHTSA) has introduced the driver fatality ratio, DFR, for different vehicle-to-vehicle categories. The DFR proposed by NHTSA is based on the actual crash statistical data, which makes it difficult to evaluate for other vehicle categories newly introduced to the market, as they do not have sufficient crash statistics. A finite element (FE) methodology is proposed in this study based on computational reconstruction of crashes and some objective measures to predict the relative risk of DFR associated with any vehicle-to-vehicle crash. The suggested objective measures include the ratios of maximum intrusion in the passenger compartments of the vehicles in crash, and the transmitted peak deceleration of the vehicles’ center of gravity, which are identified as the main influencing parameters on occupant injury. The suitability of the proposed method is established for a range of bullet light truck and van (LTV) categories against a small target passenger car with published data by NHTSA. A mathematical relation between the objective measures and DFR is then developed. The methodology is then extended to predict the relative risk of DFR for a crossover category vehicle, a light pick-up truck, and a mid-size car in crash against a small size passenger car. It is observed that the ratio of intrusions produces a reasonable estimate for the DFR, and that it can be utilized in predicting the relative risk of fatality ratios in head-on collisions. The FE methodology proposed in this study can be utilized in design process of a vehicle to reduce the aggressivity of the vehicle and to increase the on-road fleet compatibility in order to reduce the occupant injury out- come.

Amelioration of Saline Soil by the Application of Gypsum, Calcium Chloride, Rice Husk and Cow Dung

A pot experiment was conducted to investigate the effect of cow dung, rice husks, calcium chloride and gypsum on soil reclamation and compare the effect of organic and inorganic amendments on soil reclamation during the period of 5th March to 20th April, 2017. The experiment was laid to fit a completely randomized design (CRD) with seven treatments [Reference soil (T0), Cow dung (T1), Rice husk (T2), Gypsum (T3), Calcium chloride (T4), Cow dung + Rice husk (T5) and Gypsum + Calcium chloride (T6)] each having three replications for this experiment. After incubation (45 days), the laboratory investigation was carried out in the Soil, Water and Environment Discipline, Khulna University, Khulna, Bangladesh. Results indicate that the individual or combined effect of gypsum (T3) was more effective in changing EC and SAR. Gypsum application in combination with calcium chloride (T6) improved the soil chemical properties by reducing the EC. Among the treatment, calcium chloride (T4) had a remarkable effect in reducing sodium adsorption ratio and gypsum had a remarkable effect in reducing pH. Cow dung (T1), rice husk (T2), combination of cow dung and rice husk (T5) were less effective to reduce EC, pH and SAR. It’s measured for soils of different soil amendments varied significantly

Germanium/silica ratio and trace element composition of Early Cambrian siliceous rocks in Keping:implications for the siliceous rocks'formation and paleoenvironment interpretations

This study used the germanium/silica(Ge/Si)ratios,together with rare earth elements and other trace elements to infer the siliceous source and sedimentary environment of the siliceous rocks located at the bottom of Yuertusi Formation in Northwestern Tarim Basin,Keping,China.Previous studies have shown that this siliceous rock stratum formed at the edge of the carbonate platform on the continental shelf.Researchers suggest that these siliceous rocks were formed by hydrothermal activity,but some still draw different conclusions.Understanding the silicon source and depositional environment of these siliceous rocks would help us learn the processes of environmental changes and the causes of biological explosions during this period.The value of germanium/silica ratios of these siliceous rocks is from 0.15 to 0.37 pmol/mol and much lower than above 10|imol/mol values in siliceous rocks that are known formed by hydrothermal activity.All samples are rich in HREE,which differ from hydrothermal siliceous rocks that are rich in LREE.Most samples lack hydrothermal related elements.All these features show that the source of these siliceous rocks'siliceous is not hydrothermal flu ids.The samples'Ce/Ce*range from 0.88 to 1,and Th/U ratios range from 0.01 to 0.36.These features suggest these siliceous rocks were formed in an anoxic environment.Considering all the evidence,we conclude that the siliceous rock stratum at the bottom of the Lower Cambrian Yuertusi Formation in northwest Tarim Basin.Keping,was formed in anoxic seawater at the edge of the carbonate platform on the continental shelf.Its silicon source is seawater instead of hydrothermal fluid.

Research on Preparation and Influencing Fctors of High Calcium High Sulfate Ash to Autoclaved Aerated Concrete

In this paper, a high calcium high sulfate ash as the main material, adding fly ash, lime, cement, gypsum and some modifiers to prepare autoclaved aerated concrete. The products complies with the technical requirements of GB/T11968-2006. This paper also studies the influence of the physical methods and water ratio on autoclaved aerated concrete by high calcium high sulfate ash aerated concrete. The best ratio of water and Grinding time were found in practice study.

Finite element analysis on the collapse of infill walls with holes and different length-to-height ratios

Wenchuan earthquake damage survey displayed the major structures of buildings suffered only small damages,but it was common that infill walls suffered heavy damages or even collapse. To study the failure forms and collapse mechanism of infill walls in an earthquake,the influence of opening or length-to-height ratio on shake-resisting capability of filling walls was analyzed,and measures to improve the anti-collapse ability of infill walls were put forwaed. The numerical simulations on collapse process in earthquake were carried out by using ABAQUS software. We used 5 single story and single span models. It is revealed that the rigidity and compressive capacity of infill walls are reduced because of the infill walls with holes and the increases of length-to-height ratios. Adding constructional columns and horizontal beams can ensure structural integrity and improve the anti-collapse ability of the wall.

ADAPTIVE EIGENFREQUENCY ANALYSIS BY IMPROVED r-AND h-ADAPTIVE FINITE ELEMENT METHOD BASED ON PERTURBATION AND ELEMENT ENERGY RATIO

A new adaptive technique of r-and h-version for vibration problemsutilizing the matrix per- turbation theory and element energy ratiois proposed. In structural vibration analysis, through the r-conver-gence adaptvie finite element process, mesh optimization can berealized. In the light of the judgement on the changes in themagnitude of the element energy ratio, local refinement can beachieved in the process of h- convergence adaptive finite element sothat more accurate finite element solutions can be obtained with asfew meshes as possible. Many numerical examples are given and theproposed approach is shown to be feasible and effective.

DOUBLE SUBSTITUTE CALIBRATION FOR THE ISOTOPIC RATIO MEASUREMENT AMONG RARE EARTH ELEMENTS

Abstract: Through the application of the method of double substitute calibration using the true isotopic ratios of cerium and europium of our laboratory standards, the atomic weight of ytterbium has been determined as Ac(Yb) 173. 0428(15) on Zσ basis.

The spatial temporal evolution characteristics of the load／unload response ratio（LURR） and its implications for predicting the three elements of earthquakes

The spatial temPOral evolution characteristics of the load/unload response ratio (Y) before strong earthquakes is studied in this paper. The results show that the regions of high value of Y migrate and converge to the impending earthquake epicenter from different directions before the occurrence of the event. Basing on this discovery, it is proposed that the method can be used to predict the three elements of an earthquake. It was applied to predict that an earthquake would occur in the western part of Yunnan Province, southwestern China. The three elements (time, space and magnitude) of the Menglian earthquake with Ms7.3 which occurred on July 12, 1995 in Yunnan Province tallied with our prediction.

Non Degeneration of Fibonacci Series, Pascal’s Elements and Hex Series

Generally Fibonacci series and Lucas series are the same, they converge to golden ratio. After I read Fibonacci series, I thought, is there or are there any series which converges to golden ratio. Because of that I explored the inter relations of Fibonacci series when I was intent on Fibonacci series in my difference parallelogram. In which, I found there is no degeneration on Fibonacci series. In my thought, Pascal triangle seemed like a lower triangular matrix, so I tried to find the inverse for that. In inverse form, there is no change against original form of Pascal elements matrix. One day I played with ring magnets, which forms hexagonal shapes. Number of rings which forms Hexagonal shape gives Hex series. In this paper, I give the general formula for generating various types of Fibonacci series and its non-degeneration, how Pascal elements maintain its identities and which shapes formed by hex numbers by difference and matrices.

Research of Magnesium Alloy Wheel Vibration Performance Based on Finite Element Method

As the automotive industry is increasingly demanding on energy saving and environmental protection,people are taking more attention on the lightweight design and comfort of automobiles.Wheel vibration is one of the most important parts of a vehicle performance.The dynamic characteristics of the vehicle are determined by the modal parameters of the vehicle system.The wheel also has a great influence on the vibration.Based on finite element method,we analyze wheel vibration performance.This research studies the effect of different damping properties on wheel frequency.By comparing of acceleration and speed of the wheel,we can improve the vibration performance of the vehicle.

Tao and Golden Ratio: A Scientific View of Contemporary Acupunctural Principles through Geometry

It is universally accepted that the philosophy of the Tao is the essence that animates the Chinese Cosmogony. Therefore, in last decades I have tried to consolidate its scientific background, looking for solid explanations through Exact Sciences (“Between Heaven and Earth” Scientific Basis of the Action of Shao Yin: Lightning’s Physical-Mathematical Analysis”;“Is Traditional Chinese Medicine Definitely an Exact Science?”;“Euclidean Geometry and Traditional Chinese Medicine: Diving into the Real Origin of the Five Elements”;“Solitons: A Cutting-Edge Scientific Proposal Explaining the Mechanisms of Acupuntural Action”) Currently, research on Chinese medicine leads us—with Dr. Erica Arakaki, collaborator and assistant—to verify through a profound bibliographic review the application of Fibonacci’s Golden Ratio in the constitution of T’ai Ji Tu, adding yet more substance to the hypothesis of Acupuncture and demonstrating how said Chinese Ancient Science is not only an empirical knowledge but a wisdom derived from the most ancient exact science: Geometry.