Short communication:Extreme glacier mass loss triggered by high temperature and drought during hydrological year 2022/2023 in Qilian Mountains

In the hydrological year 2022/2023,the glaciers in the Qilian Mountains experienced unprecedented mass loss.The glacier-wide mass balance was-1,188 mm w.e.,in contrast to-350 mm of average mass balance since 1990 over the Bailanghe Glacier No.12 in the middle of Qilian Mountains.The temperature during 2022–2023 reached the highest value ever recorded,second only to 2022,while at the same time the precipitation amount was less compared to other year since 2000,which together led to the strongest glacier mass loss during 2022–2023.The atmospheric circulation analysis shows that the high temperature in the Qilian Mountains in 2023 was jointly caused by the Arctic air mass and East Asian monsoon.

Eco-friendly physical blowing agent mass loss of bio-based polyurethane rigid foam materials

Through systematical experiment design, the physical blowing agent(PBA) mass loss of bio-based polyurethane rigid foam(PURF)in the foaming process was measured and calculated in this study, and different eco-friendly PBA mass losses were measured quantitatively for the first time. The core of the proposed method is to add water to replace the difference, and this method has a high fault tolerance rate for different foaming forms of foams. The method was proved to be stable and reliable through the standard deviations σ1and σ2for R1(ratio of the PBA mass loss to the material total mass except the PBA) and R2(ratio of the PBA mass loss to the PBA mass in the material total mass) in parallel experiments. It can be used to measure and calculate the actual PBA mass loss in the foaming process of both bio-based and petroleumbased PURF. The results show that the PBA mass loss in PURF with different PBA systems is controlled by its initial mass content of PBA in PU materials ω. The main way for PBA to dissipate into the air is evaporation/escape along the upper surface of foam. This study further reveals the mechanism of PBA mass loss: the evaporation/escape of PBA along the upper surface of foam is a typical diffusion behavior. Its spread power comes from the difference between the chemical potential of PBA in the interface layer and that in the outside air. For a certain PURF system, R1has approximately linear relationship with the initial mass content of PBA in PU materials ω, which can be expressed by the functional relationship R1= kω, where k is a variable related to PBA’s own attributes.

Stability analyses of the mass abrasive projectile high-speed penetrating into concrete target. Part Ⅰ: Engineering model for the mass loss and nose-blunting of ogive-nosed projectiles

The mass loss and nose blunting of a projectile during high-speed deep penetration into concrete target may cause structural destruction and ballistic trajectory instability of the penetrator,obviously reducing the penetration efficiency of penetrator.Provided that the work of friction between projectile and target is totally transformed into the heat to melt penetrator material at its nose surface,an engineering model is established for the mass loss and nose-blunting of the ogive-nosed projectile.A dimensionless formula for the relative mass loss of projectile is obtained by introducing the dimensionless impact function I and geometry function N of the projectile.The critical value V c0of the initial striking velocity is formulated,and the mass loss of projectile tends to increase weakly nonlinearly with I/N when V0〉V c0,whilst the mass loss is proportional to the initial kinetic energy of projectile when V0

Parametric study on mass loss of penetrators

Earth penetration weapon （EPW） is applicable for attacking underground targets protected by reinforced concrete and rocks. With increasing impact velocity, the mass loss/abrasion of penetrator increases, which significandy decreases the penetration efficiency due to the change of nose shape. The abrasion may induce instability of the penetrator, and lead to failure of its structure. A common disadvantage, i.e. dependence on corresponding experimen- tal results, exists in all the available formulae, which limits their ranges of application in estimating the mass loss of penetrator. In this paper, we conduct a parametric study on the mass loss of penetrator, and indicate that the mass loss of penetrator can be determined by seven variables, i.e., the initial impact velocity, initial nose shape, melting heat, shank diameter of projectile and density and strength of target as well as the aggregate hardness of target. Further discussion on factors dominant in the mass abrasion of penetrator are given, which may be helpful for optimizing the target or the projectile for defensive or offensive objectives, respectively.

GRACE observed mass loss in the middle and lower Yangtze basin

Anthropogenic architectures have a significant impact to the environment. The Three Gorges Dam(TGD),as the largest dam in the world, is a typical example, and has influenced the mass anomalies transported by the flow downstream in the Yangtze River since June 2003. However, the evidence of TGD influence on downstream mass transportation is not documented. In this study, we analyze the monthly gravity solutions from GRACE to investigate the downstream mass variations of Yangtze River. From our results,the considerable mass loss is detected in the downstream of TGD. By comparing our estimations with the in situ water level data of TGD, we find that the mass variations derived from GRACE at Datong station decreases shortly after the impoundment of TGD. This confirms a strong connection between them.Furthermore, by comparing with the in situ sediment load and river discharge at Yichang and Datong gauging stations, we find that the sediment load data shows a similar mass loss signature while the river discharge of both stations has stay at a relative stable level. This indicates that further study is still needed to understand the mechanism better.

The kinetic of mass loss of grades A and B of melted TNT by isothermal and non-isothermal gravimetric methods

The kintic and activation energy of mass loss of two grades of melted TNT explosive, grade A and grade B, with freezing points of 80.57 and 78.15 ℃, respectively, were studied by isothermal and nonisothermal gravimetric methods. In isothermal method, the mass loss of samples in containers of glass and aluminum was followed in temperatures of 80, 90 and 100 ℃. The kinetic of the mass loss of the samples in the aluminum container was higher than the kinetic of it in the glass container that can be related to the effects of heat transfer and catalytic of aluminm metal. Also, the presence of impurities in grade B was due to increasing of kinetic of mass loss of it versus grade A. The non-isothermal curves were obtained in range of 30-330 ℃ at heating rates of 10,15 and 20 ℃·min^(-1).The TG/DTG data were used for determination of activation energy(E_a) of mass loss of TNT samples upon degradation by using Ozawa, Kissinger, Ozawa-Flynn-Wall(OFW) and Kissinger-Akahira-Sunose(KAS) methods as model free methods. The activation energies of grades of A and B of TNT was obtained 99-120 and 66-70 kJ mol^(-1)respectively. The lower values of activation energy of the degradation reaction of grade B confirm the effect of impurities in the kinetics of mass loss of this grade.

Prediction of Pitting Corrosion Mass Loss for 304 Stainless Steel by Image Processing and BP Neural Network

Image processing technique was employed to analyze pitting corrosion morphologies of 304 stainless steel exposed to FeCl3 environments. BP neural network models were developed for the prediction of pitting corrosion mass loss using the obtained data of the total and the average pit areas which were extracted from pitting binary image. The results showed that the predicted results obtained by the 2-5-1 type BP neural network model are in good agreement with the experimental data of pitting corrosion mass loss. The maximum relative error of prediction is 6.78%.

Synthesis of biodegradable Mg-Zn alloy by mechanical alloying: Statistical prediction of elastic modulus and mass loss using fractional factorial design

Biodegradable Mg-Zn alloy was synthesized using mechanical alloying where a statistical model was developed using fractional factorial design to predict elastic modulus and mass loss of the bulk alloy.The effects of mechanical alloying parameters(i.e.,milling time,milling speed,ball-to-powder mass ratio and Zn content)and their interactions were investigated involving 4 numerical factors with 2 replicates,thus 16 runs of two-level fractional factorial design.Results of analysis of variance(ANOVA),regression analysis and R2 test indicated good accuracy of the model.The statistical model determined that the elastic modulus of biodegradable Mg-Zn alloy was between 40.18 and 47.88 GPa,which was improved and resembled that of natural bone(30-57 GPa).Corrosion resistance(mass loss of pure Mg,33.74 mg)was enhanced with addition of 3%-10%Zn(between 9.32 and 15.38 mg).The most significant independent variable was Zn content,and only the interaction of milling time and ball-to-powder mass ratio was significant as P-value was less than 0.05.Interestingly,mechanical properties(represented by elastic modulus)and corrosion resistance(represented by mass loss)of biodegradable Mg-Zn alloy can be statistically predicted according to the developed models.

Moisture Absorption, Mass Loss and Evaporative Resistance of Clothing in Transient Condition

The water vapour resistance of clothing ensembles is not as commonly determined as dry thermal insulation. The measurement techniques are more complicated and the measurement values differ among laboratories. Due to complicated moisture transfer process through clothing ensemble, the moisture absorbed and evaporated varies in transient and steady state phases depending on properties, thickness of clothing, and environmental conditions. The purpose of this study was to measure moisture gain inside hygroscopic underwear, and hydrophobic and permeable outer wear as a function of time, to investigate mass loss from ＂skin＂ as well as from the manikin, to quantify evaporative heat loss and total heat loss from the manikin, and to determine water vaponr resistance of clothing. Manikin Tore was used by wearing wet ＂skin＂ to simulate sweating condition. Moisture content in the inner garment gain shows an exponential relation against time. Moisture in the outer permeable layer shows little gain. On the contrary, mass loss directly from the wet skin decreases exponentially. The mass loss from the manikin is relatively stable throughout three test phases. The evaporative heat loss is about 2/3 of the total heat loss from the sweating manikin. While measuring the evaporative resistance of clothing ensembles with hygroscopic inner garment and permeable outer garment, unlike to measure ensembles with impermeable outer layer, one hour measurement time is enough to get relatively stable results. The variation between the 1^rt hour and the 3^nd hour is less than 5%. The length of transient period and measurement time is dependent on the permeability, thickness of clothing ensembles and environmental conditions.

Microstructure of coupled Al/gray cast iron obtained by molding and its effect on mass loss

This study aims to consolidate the surface of gray cast iron with aluminum deposition by developing a method that combines the preparation and surface treatment in a single operation. The effect of the wall thickness of the castings on the microstructure of the formed layers was studied, and two thicknesses, 8 mm and 25 mm, were studied. The formation of a continuous and homogeneous rich aluminum layer on the surface of the cast iron was observed. The formed layer is composed of two successive zones identified as two proeutectoid phases FeAl+FeAl/FeAl2 and single-phase FeAl, which significantly increases the surface hardness. Furthermore, this change in surface composition makes it possible to reduce the mass of the immersed samples in a 1 M hydrochloric acid solution during different exposure times(1 to 4 days). Consequently, a clear improvement in the corrosion resistance of the treated layers is highlighted.

Orbital effects of Sun’s mass loss and the Earth’s fate

I calculate the classical effects induced by an isotropic mass loss of a body on the orbital motion of a test particle around it;the present analysis is also valid for a variation of the Newtonian constant of gravitation. I perturbatively obtain negative secular rates for the osculating semimajor axis a, the eccentricity e and the mean anomaly , while the argument of pericenter ω does not undergo secular precession, like the longitude of the ascending node Ω and the inclination I. The anomalistic period is different from the Keplerian one, being larger than it. The true orbit, instead, expands, as shown by a numerical integration of the equations of motion in Cartesian coordinates;in fact, this is in agreement with the seemingly counter-intuitive decreasing of a and e because they only refer to the osculating Keplerian ellipses which approximate the trajectory at each instant. By assuming for the Sun it turns out that the Earth's perihelion position is displaced outward by 1.3 cm along the fixed line of apsides after each revolution. By applying our results to the phase in which the radius of the Sun, already moved to the Red Giant Branch of the Hertzsprung-Russell Diagram, will become as large as 1.20 AU in about 1 Myr, I find that the Earth's perihelion position on the fixed line of the apsides will increase by AU (for );other researchers point towards an increase of AU. Mercury will be destroyed already at the end of the Main Sequence, while Venus should be engulfed in the initial phase of the Red Giant Branch phase;the orbits of the outer planets will increase by AU. Simultaneous long-term numerical integrations of the equations of motion of all the major bodies of the solar system, with the inclusion of a mass-loss term in the dynamical force models as well, are required to check if the mutual N-body interactions may substantially change the picture analytically outlined here, especially in the Red Giant Branch phase in which Mercury and Venus may be removed from the integration.

Effect of Cooking Condiments on the Mass Loss of Artisanal Aluminum Cooking Utensils: The Case of Congo—Brazzaville

Corrosion of cookware is a growing concern for the durability of materials. A rapidly emerging theme that is one of the major current societal challenges at the interface of environmental and health issues. In this present work, the corrosion of aluminum in food environments (salt water and fresh tomatoes) was studied. The three aluminum utensils were purchased in the various workshops in Brazzaville (Republic of the Congo). The weight loss method followed the effect of cooking media on cookware, X-ray diffraction (XRD) and fluorescence (XRF) are two methods used to characterize alloys. XRF analysis indicates that the samples consist of aluminum as a basic element. XRD reveals that the essential building blocks of cookware samples are aluminum, silicon, iron, copper, magnesium and zinc. Finally, gravimetric measurements are carried out to assess the mass losses of samples of artisanal kitchen utensils when cooking food. Aluminum is found to be sensitive in TF and OS media.

盐冻耦合环境下再生砖粉ECC的耐久性研究

利用再生砖粉取代工程水泥基复合材料(ECC)中的石英砂,制备再生砖粉ECC,采用混凝土快速冻融试验,研究了氯盐、硫酸盐及复合盐(氯盐+硫酸盐)溶液侵蚀作用下再生砖粉ECC的质量损失率和相对动弹性模量变化规律,建立了ECC在盐冻侵蚀环境下的损伤模型,并对其耐久性进行评价。结果表明:冻融循环300次后,再生砖粉ECC在清水、氯盐、硫酸盐及复合盐四种介质中的质量损失率分别为2.884%、4.984%、1.955%和6.891%,相对动弹性模量分别下降了6.468%、16.300%、24.303%和39.861%;再生砖粉ECC在单一盐冻情况下的抗冻等级大于F300,在复合盐冻情况下的抗冻等级大于F250,具有良好的抗盐冻性能;建立的冻融损伤模型可较好地反映ECC在不同冻融介质下的损伤度Dn与冻融循环次数的关系,可以为严寒地区的结构耐久性设计提供有效参考。

铁尾矿混凝土力学性质及耐久性

这是一篇陶瓷及复合材料领域的论文。为了研究铁尾矿混凝土在受硫酸钠溶液干湿循环作用后的力学特性和耐久性,开展了受硫酸钠溶液侵蚀混凝土的抗压实验、抗氯离子侵蚀实验、抗冻实验和水化特性实验,分析不同铁尾矿掺量、干湿循环次数、溶液浓度对混凝土力学性质和耐久性的影响。结果表明:在铁尾矿掺量为30%、干湿循环次数为60次和硫酸钠浓度为5%时,混凝土的质量损失率较小而抗压强度耐腐蚀系数较大。随着铁尾矿掺量的不断增大,混凝土的抗氯离子侵蚀性能、抗冻性能越好,水化反应放热量不断减小。

考虑过程能力指数的参数和容差并行设计方法

针对传统田口产品优化设计中先参数设计后容差设计试验次数多、制造成本高的问题,引入非对称质量损失和考虑过程能力指数的参数和容差并行设计,在保证产品质量的同时,有效的节约了制造成本。首先,进行中心复合试验设计,再由试验数据建立均值和方差的响应曲面模型;随后提出非对称质量损失函数以及根据经验数据建立容差成本模型,之后再构建改进的过程能力指数;最后将非对称质量损失函数和容差成本模型代入过程能力指数函数中,并利用改进遗传算法(NSGA-Ⅱ)寻优同时得出参数及其容差组合。通过桥式放大机构试验的实例分析,说明该方法提高了产品的质量性能,并减少了生产运作成本。

水泥-石灰和水泥-稻壳灰稳定土的力学性能和冻融耐久性研究

为研究水泥-石灰和水泥-稻壳灰对土体进行加固良的效果及掺量,利用水泥、石灰和稻壳灰分别以水泥∶石灰=1∶1和水泥∶稻壳灰=1∶1制备两种稳定掺料。按照掺入比分别0%、2.5%、5%、7.5%和10%制备稳定土试样,并通过力学试验以及冻融试验对两种稳定土的三轴力学特性以及抗冻融循环的性能进行研究。结果表明:随着围压、稳定掺料和龄期的增加,稳定土的强度逐渐增加;脆性也明显增强;稳定土在3~7 d的强度增长率明显大于7~28 d的强度增长率,且在相同条件下,水泥-石灰稳定土的强度大于水泥-稻壳灰稳定土的强度。冻融循环后质量损失率和超声波变化规律表明土样的冻融耐久性顺序为:水泥-稻壳灰稳定土>水泥-石灰稳定土>纯土。

铁尾矿粉对石灰石粉混凝土力学性能和氢氧化钙含量的影响

这是一篇陶瓷及复合材料领域的论文。本文研究了复掺铁尾矿粉和石灰石粉的掺量和比例对混凝土性能的影响。结果表明:随着复掺矿粉比例的不断增大,复掺矿粉混凝土强度均呈现出先增大后减小的变化规律,并在复掺矿粉比例为1∶2时取得较大值。在同一冻融循环次数作用下,混凝土质量损失率随着复掺矿粉比例的增大呈现出先减小后增大的趋势,而混凝土的相对动弹性模量却呈现出先增大后减小的变化趋势。在同一测定位置处,随着复掺矿粉比例的不断增大,复掺矿粉混凝土氯离子含量均呈现出不断减小,且在比例为1∶2时复掺矿粉混凝土氯离子含量的下降变快。综合实验结果得到,石灰石粉掺量为20%时混凝土的强度特性较佳,复掺矿粉比例为1∶2时混凝土的强度和耐久性均达到较佳。

高温后预损伤混凝土的轴压试验研究

对不同预损伤程度下C30混凝土试件进行了高温(200、350、500℃)后轴心抗压试验,获取了试件的应力-应变全曲线,分析了高温对预损伤试件的质量损失率、峰值应力、峰值应变、弹性模量等的影响。结果表明:在相同温度下,预损伤程度越高的混凝土试件破坏越早;在相同预损伤程度下,高温温度越高,试件破坏越早;与温度相比,预损伤程度对试件轴压破坏的影响更大;各试件的质量损失率随着温度的升高而增加;预损伤程度越高,高温温度越高,试件的轴心抗压强度越低;随着温度的升高,各试件的峰值应力降低,峰值应变增加,上升段的斜率变小;各试件的弹性模量均随着温度的升高而降低。

纳米SiO_(2)增强高强套筒灌浆料及高温后性能试验研究

研究了常温下不同纳米SiO_(2)(NS)掺量(0、0.4%、0.8%、1.2%、1.6%、2.0%)对高强套筒灌浆料流动度和强度的影响,以及不同高温温度(150、200、250℃)下NS掺量对高强套筒灌浆料质量损失和强度的影响,并进行了微观机理分析。结果表明:常温下,NS的掺入降低了灌浆料的流动度,灌浆料的强度随NS掺量的增加先增大后降低;高温后,灌浆料的质量损失率随温度的升高逐渐增大,抗折强度逐渐降低,抗压强度先增大后降低;NS的掺入能够降低灌浆料的质量损失率和抗折强度损失率,提高抗压强度,且随着NS掺量的增加,质量损失率和抗折强度损失率先降低后增大;NS能够改善灌浆料的内部孔结构;随着温度的升高,灌浆料的内部结构先密实后疏松。

矿物掺合料对混凝土抗复合侵蚀的影响

为明确矿物掺合料对混凝土抗复合侵蚀的影响,在混凝土中分别掺加粉煤灰和硅灰,以明确矿物掺合料对混凝土抵抗硫酸盐-氯盐复合侵蚀能力的影响。研究分析了混凝土在历经若干次干湿循环后的抗压强度、质量损失率和动弹性模量损失变化,结合XRD、SEM和工业CT等表征方法,揭示了两类矿物掺合料对抗复合侵蚀性能的影响机理。结果表明粉煤灰和硅灰的掺加在复合侵蚀条件下可以显著改善混凝土的微观结构和宏观性能,降低有害孔的数量,从而提高材料耐久性。矿物掺合料通过物理填充和化学反应双重机制,有效地提升了混凝土在硫酸盐-氯盐复合侵蚀环境中的性能。研究结果为混凝土抵抗硫酸盐-氯盐复合侵蚀的性能研究提供了理论指导和依据。