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Determination of critical state line(CSL)for silty-sandy iron ore tailings subjected to low-high confining pressures

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Journal of Rock Mechanics and geotechnical Engineering 2024年第5期16卷 1684-1695页

作者： Nilo Cesar Consoli João Vítor de Azambuja Carvalho Alexia Cindy Wagner Hugo Carlos Scheuermann Filho Inácio Carvalho Pedro Pazzoto Cacciari João Paulo de Sousa Silva Civil Engineering Universidade Federal do Rio Grande do SulPorto AlegreRS90035-190Brazil Exploration and Mineral Projects-Mineral Development Centre VALE S.A.Santa LuziaMG33040-900Brazil Department of Civil Geological and Mining EngineeringPolytechnique MontrealQuebecH3C 3A7Canada

The disposal of filtered tailings in high dry stacks can induce particle breakage,changing the material's behaviour during the structure's *** grading changes influence material properties at the critical state,and this is not mature for intermediate artificial soils(tailings)in a broad range of confining *** this paper,it aims to describe the behaviour of iron ore tailings in a spectrum of confining pressures broader than the reported in previous studies.A series of consolidated drained(CD)triaxial tests was carried out with confining pressures ranging from 0.075 MPa to 120 *** results show that the amount of breakage plays an essential role in the response of iron ore *** existence of curved critical state line(CSL)in both specific volume(ν)-logarithm of mean effective stress(p′)and deviatoric stress(q)-mean effective stress(p′)planes,and different responses in the deviatoric stress-axial strain-volumetric strain curves were *** inverse S-shaped equation was proposed to represent the silty-sandy tailings'behaviour up to high pressures onν-lnp′*** proposed equation provides a basis for enhancing constitutive models and considers the evolution of the grading up to severe loading *** adjustment considered three regions with different responses associated with particle breakage at different pressure levels.

关键词： Tailings Iron ore tailings dry stacking Silty-sandy material Critical state soil mechanics High confining pressures Particle breakage

Optimal transcorneal electrical stimulation parameters for preserving photoreceptors in a mouse model of retinitis pigmentosa

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Neural Regeneration Research 2024年第11期19卷 2543-2552页

作者： Sam Enayati Karen Chang Anton Lennikov Menglu Yang Cherin Lee Ajay Ashok Farris Elzaridi Christina Yen Kasim gunes Jia Xie Kin-Sang Cho tor Paaske utheim Dong Feng Chen Schepens Eye Research Institute of Massachusetts Eye and Ear Department of OphthalmologyHarvard Medical SchoolBostonMAUSA Institute of clinical medicine Faculty of MedicineUniversity of OsloOsloNorway Department of Medical Biochemistry Oslo University HospitalUniversity of OsloOsloNorway Department of Ophthalmology Drammen HospitalVestre Viken Hospital TrustDrammenNorway Department of Histology and Embryology School of MedicineMarmara UniversityIstanbulTurkiye

Retinitis pigmentosa is a hereditary retinal disease that affects rod and cone photoreceptors,leading to progressive photoreceptor *** research supports the beneficial effect of electrical stimulation on photoreceptor *** study aims to identify the most effective electrical stimulation parameters and functional advantages of transcorneal electrical stimulation(tcES)in mice affected by inherited retinal ***,the study seeked to analyze the electric field that reaches the retina in both eyes in mice and post-mortem *** this study,we recorded waveforms and voltages directed to the retina during transcorneal electrical stimulation in C57BL/6J mice using an intraocular needle probe with rectangular,sine,and ramp *** investigate the functional effects of electrical stimulation on photoreceptors,we used human retinal explant cultures and rhodopsin knockout(Rho^(-/-))mice,demonstrating progressive photoreceptor degeneration with *** retinal explants isolated from the donors’eyes were then subjected to electrical stimulation and cultured for 48 hours to simulate the neurodegenerative environment in *** density was evaluated by rhodopsin *** vivo Rho^(-/-)mice were subjected to two 5-day series of daily transcorneal electrical stimulation using rectangular and ramp *** function and visual perception of mice were evaluated by electroretinography and optomotor response(OMR),*** was used to assess the morphological and biochemical changes of the photoreceptor and bipolar cells in mouse *** recordings indicated effective delivery of rectangular,sine,and ramp waveforms to the retina by transcorneal electrical stimulation,of which the ramp waveform required the lowest *** of the total conductive resistance of the post-mortem human compared to the mouse eyes indicated higher cornea-to-retina resistance in human *** tem

关键词： bipolar cells electrical stimulation neuroprotection photoreceptor degeneration retina retinal explants retinitis pigmentosa transcorneal electrical stimulation waveform

Efficacy of Cyanoacrylate Tissue Adhesive Application in the Management of Corneal Perforations at Preah Ang Duong Hospital in Cambodia

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Open Journal of Ophthalmology 2024年第1期14卷 44-54页

作者： guechlaing Chea Amarin Mar Saly Saint Remy tor Ponndara Ith Piseth Kong Ophthalmology Department Preah Ang Duong Hospital Phnom Penh Cambodia Faculty of Medicine University of Health Sciences Phnom Penh Cambodia

Purpose: The study was to evaluate the efficacy of cyanoacrylate tissue adhesive (CTA) application in corneal perforations. Method: This was a prospective study on 20 patients of corneal perforations who received cyanoacrylate tissue adhesive application as treatment between March 2021 and March 2022 at Preah Ang Duong Hospital. The primary outcome measure was success rate of CTA application, while the secondary outcome was to measure postoperative best-corrected visual acuity (BCVA) and ocular complications. Results: The mean age of patients was 44.15 ± 16.05 years old and 7 (35%) were female. Causes of perforation were microbial infection in 12 patients (60%), trauma in 5 patients (25%), and sterile melting in 3 patients (15%). The perforation of size smaller than 1.5 mm was in 8 patients (40%) while 12 patients (60%) had perforated size between 1.5 mm to 3 mm. The perforation was 60% (12 patients) central, 25% (5 patients) paracentral, and 15% (3 patients) peripherally. Out of 20 patients, 5 patients (25%) received CTA application more than 1 time. The mean glue retention was 57.60 ± 31.84 days. Success rate of glue application (defined as intact globe without surgical intervention regardless of number of CTA applications) was 85%. At the last visit, 7 patients (35%) had BCVA of 6/120 or better. Common complications were uveitis (45%), ocular hypertension (30%), cataract (25%) and neovascularization (20%). No serious complications were found. Conclusion: Cyanoacrylate tissue adhesive is an effective treatment option in sealing corneal perforations with no serious complications. .

关键词： Cyanoacrylate Tissue Adhesive Corneal Perforation Microbial Infection Sterile Melting

Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

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Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： gürel Cam Ali günen Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Mechanical Engineering31200 Iskenderun-HatayTurkey Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Metallurgy and Materials Engineering31200 Iskenderun-HatayTurkey

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport ***,their widespread application is hindered by their low formability at room temperature due to limited slip *** Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high *** casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain *** metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast ***,MAM is a promising technique to produce Mg alloy *** energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive ***,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this *** review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and ***,the predominant imperfections,notably inhomo

关键词： Additive manufacturing DED processes Arc-DED Wire arc additive manufacturing(WAAM) 3-D printing High deposition rate

Recent research in mechanical properties of geopolymer-based ultrahigh-performance concrete:A review

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Defence Technology（防务技术） 2024年第2期32卷 67-88页

作者： g.Murali Division of Research&Innovation Uttaranchal UniversityDehradun 248007India

Due to the growing need for sustainable and ultra-high-strength construction materials,scientists have created an innovative ultra-high-performance concrete called geopolymer based ultra-highperformance concrete(gUHPC).Besides,in the last few decades,there have been a lot of explosions and ballistic attacks around the world,which have killed many civilians and fighters in border *** this context,this article reviews the fresh state and mechanical properties of ***,the ingredients of gUHPC and fresh properties such as setting time and flowability are briefly ***,the review of compressive strength,flexure strength,tensile strength and modulus of elasticity of fibrous ***,the blast and projectile impact resistance performance was ***,the microstructural characteristics were reviewed using the scanning electron microscope and X-ray Powder *** review outcome reveals that the mechanical properties were increased when 30%silica fume was added to a higher dose of steel fibre to improve the microstructure of *** is hypothesized that the brittleness of gUHPC was mitigated by adding 1.5%steel fibre reinforcement,which played a role in the decrease of contact explosion cratering and *** the need for cement in gUHPC was a key factor in the review,indicating a promising potential for lowering carbon ***,gUHPC research is still in its early stages,so more study is required before its full potential can be utilized.

关键词： Mechanical properties Blast Projectile impact Fibre geopolymer Silica fume Alkaline activators

Nitrogen mineralization in the oldest climax communities in the eastern Mediterranean region

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Journal of Forestry Research 2024年第1期35卷 213-228页

作者： Fatma Selcen Sakar gürcan güleryüz Department of Biology Section Ecology GörükleGraduate School of Natural and Applied ScienceUniversity of Bursa Uludağ16059 NilüferBursaTurkey Department of Biology Section Ecology GörükleFaculty of Science and ArtsUniversity of Bursa Uludağ16059 NilüferBursaTurkey

In this study,we investigated how tree species affect N mineralization in connection to some soil properties and seconder metabolite levels of litter,in the soil of the old-est native forest *** the oldest pure communi-ties of Pinus nigra(PN),Fagus orientalis(FO),and Abies bornmuelleriana(AB)in the mountain range of Mount Uludağ,Bursa,Turkey,annual net yield and N mineraliza-tion in the 0-5-and 5-20-cm soil layers were determined in a field incubation study over 1 *** locations were chosen from 1300 to 1600 m a.s.l.,and moisture content(%),pH,water-holding capacity(%),organic C,total N,and C/N ratio,and annual net mineral N yield of the soil and hydro-lyzed tannic acid and total phenolic compounds in litter were compared for these forest *** had the highest annual net Nmin yield(43.9±4.8 kg ha^(-1) a^(-1)),*** the lowest(30.5±4.2 kg ha^(-1) a^(-1)).Our findings show that in the oldest forest ecosystems,the seasonal soil moisture content and tree species play an essential role in N cycling and that hydrolyzed tannic acids and total phenolic compounds effectively control N *** acid and total phenolics in the litter were found to inhibit nitrification,but total phenolics were found to stimulate ammonification.

关键词： Oldest forest communities Nitrogen mineralization Nitrification Tannic acid Total phenolic Litter

Shell-model representations of the microscopic version of the Bohr-Mottelson collective model

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Communications in Theoretical Physics 2024年第8期76卷 79-90页

作者： H g ganev Joint Institute for Nuclear Research DubnaRussia Institute of Mechanics Bulgarian Academy of SciencesSofiaBulgaria

The structure of the irreducible collective spaces of the group Sp(12,R),which many-particle nuclear states are classified according to the chain Sp(12,R)⊃U(6)⊃SO(6)⊃SU_(pn)(3)⊗SO(2)⊃SO(3)of the proton-neutron symplectic model(PNSM),is considered in *** chain of the PNSM was recently shown to correspond to a microscopic shell-model version of the Bohr-Mottelson collective *** construction of the relevant shell-model representations of the Sp(12,R)group along this chain is considered for three nuclei with varying collective properties and from different mass *** is shown that the SU_(pn)(3)basis states of the Sp(12,R)representations belonging to the SO(6)irreps with seniorityυ≥υ0,withυ0 denoting the maximal seniority SO(6)irrep contained in the Sp(12,R)bandhead,are always Pauli allowed,but organized in a different way into different SO(6)*** is in contrast to the case of filling the levels of the standard three-dimensional harmonic oscillator and using the plethysm *** the SU_(pn)(3)multiplets withinυ<υ0 are not all Pauli forbidden,it is safe to discard *** results obtained in the present work are important for the practical application of the microscopic version of the Bohr-Mottelson collective model.

关键词： microscopic shell-model version of the Bohr-Mottelson model proton-neutron symplectic model Sp(12,R)dynamical algebra shell-model representations

Epidemiologic, Diagnostic, and Therapeutic Features of Urinary Stone Disease in Northern Benin from 2018 to 2023

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Open Journal of Urology 2024年第2期14卷 128-137页

作者： gandaho Isidore Sossa Jean toré Sanni Rafiou Dènon Emmanuel Allodé Alexandre Avakoudjo Déjinnin Josué georges Département de Chirurgie et Spécialités Chirurgicales Université de Parakou Parakou Bénin Faculté des Sciences de la Santé Université d’Abomey-Calavi Abomey-Calavi Bénin

Objective: To determine the epidemiologic, diagnostic, and therapeutic features of urinary in northern Benin from 2018 to 2023. Patients and Method: The study was an observational and descriptive one. We exhaustively and retrospectively collected data from the medical records of the patients that were managed from February 1, 2018 to February 1, 2023 at the Department of Surgery of “Centre Hospitalier Universitaire Départmental Borgou-Alibori or CHUD-BA”. Results: Among the 4522 patients managed, 75% or 1.7% had urinary stone disease. Their mean age was 41 years. The sex ratio was 2.75, the males being predominantly affected. Of the 75 cases of urinary stone disease, 30.7% (n = 23) were renal, 46.7% (n = 35) were ureteral, and 22.7% (n = 17) were vesical. The patients came from variable geographical areas, ethnic groups, and professional sectors. Their main complaints were pain (57.3%), hematuria (14.7%), dysuria (12%), and fever (5.3%). 15 (20%) patients, i.e., 7 renal stone and 8 ureteral stone patients, had an obstructive renal failure. The imaging tools available were ultrasonography, tomography and computed tomographic scan. 11 of the bladder stone cases (64.7%) were associated with a bladder outlet obstruction. Overall, 38.7% of the patients had either diabetes mellitus (6.7%), hypertension or high blood pressure (6.7%), benign prostate hyperplasia (8%), urinary schistosomiasis (6.7%), ureteral pelvic junction obstruction (2.7%), and prostate cancer (1.3%). Of the 19 patients whose dietary behavior was investigated 15 (79%), 11 (57.9%) et 11 (57.9%) demonstrated a diet which was respectively rich in milk, fromage and meat. 100% of bladder stones were removed through cystolithotomy. Renal stones were removed by pyelolithtomy (52.2%) and nephrolithotomy (21.7%). Ureteral stones were removed through ureterolithotomy (40%), expelled by means of alpha-blockers (40%) or managed with ureteral pigtail stent (20%). Conclusion: The hospital prevalence of urinary stone d

关键词： Urinary Stone Epidemiologic Diagnostic Therapeutic

Harmonics in the Squirrel Cage Induction Motor Analytic Calculation Part III: Influence on the torque-speed Characteristic

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 86-102页

作者： g.Kovács the ganz Electric Works BudapestHungary

The harmonics that appear in the squirrel cage asynchronous machine have been discussed in great detail in the literature for a long time. However, the systematization of the phenomenon is still pending, so we made an attempt to fill this gap in the previous parts of our study by elaborating formulas for calculation of parasitic torques. It was a general demand among those who work in this field towards the author to verify his formulas with measurements. In the literature, it seems,only one detailed, purposeful series of measurements has been published so far, the purpose of which was to investigate the effect of the number of rotor slots on the torque-speed characteristic curve of the machine. The main goal of this study is to verify the correctness of the formulas by comparing them with the referred series of measurements. Relying on this, the expected synchronous parasitic torques were developed for the frequently used rotor slot numbers-as a design guide for the ***, together with our complete table for radial magnetic pull published in our previous work, the designer has all the principles, data and formulas available for the right number of rotor slots for his given machine and for the drive system. This brings this series of papers to an end.

关键词： Asynchronous parasitic torques Induction motor Squirrel cage rotor Space harmonics Synchronous parasitic torques