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Application of a finite element method to stress distribution in buried patch repaired polyethylene gas pipes

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Underground Space 2019年第1期4卷 48-58页

作者： R.Khademi-zahedi m.Shishesaz Shahid Chamran University of Ahvaz AhvazIran

Advantages of polyethylene pipes over traditional steel or metal pipes have increased industry interest in the use of polyethylene(PE)pipelines for underground applications and especially in gas distribution *** this study,finite element analysis is used to calculate the stress distribution in a patch repaired defective gas pipe under internal *** pipe is assumed to be buried at a depth of 125 *** material is assumed to be medium density PE80B,where the patch material was selected from high density polyethylene(HDPE).During the loading process,the seasonal pipe temperature changes,surcharge loads,soil column weight,and soil-pipe interaction were included in the *** types of patch arrangements were selected to repair the damaged *** shape of the defect hole was deemed as circular or *** respect to elliptic defects,various minor to major diameter ratios,a/b,were selected to simulate a circular to a crack shaped *** on the results,the semi-circular and saddle fusion patches decrease the peak von mises stress in the pipe by almost the same ***,the minimum peak von mises stress in the patch corresponds to the saddle fusion repair *** on the results,with respect to a saddle fusion repair,when the shape of the defect approaches a crack,the peak von mises stress in the pipe almost doubles and exceeds the pipe allowable stress for a working life of 50 *** respect to higher values of a/b,the stress level in the patch repaired pipe is significantly below its limiting value for the same life expectancy.

关键词： Patch repair Buried gas pipe mDPE HDPE Temperature variation

Sleep as a window to understand and regulate Alzheimer's disease:emerging roles of thalamic reticular nucleus

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Neural Regeneration Research 2025年第6期20卷 1711-1712页

作者： Haoqi Sun Shiqian Shen Robert j.Thomas m.Brandon Westover Can Zhang Department of Neurology Beth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMAUSA Center for Translational Pain Research Department of AnesthesiaCritical Care and Pain MedicineMassachusetis General HospitalHarvard Medical SchoolBostonMAUSA Division of Pulmonary Critical Care and Sleep MedicineDepartment of MedicineBeth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMAUSA Genetics and Aging Research Unit McCance Center for Brain HealthMass General Institute for Neurodegenerative DiseaseDepartment of NeurologyMassachusetts General HospitalHarvard Medical SchoolBostonMAUSA

Introduction:Alzheimer 's disease(AD) is a common neurodegenerative disorder and the primary cause of dementia. Considerable evidence supports the “amyloid hypothesis,” stating that the pathogenesis of AD is primarily caused by the deposition of amyloid-β(Aβ), which drives tau phosphorylation, neuroinflammation, and neurodegeneration in the brain. The amyloid hypothesis is strengthened by the significant and moderate benefit of lecanemab, a humanized antibody through an anti-amyloid mechanism,showing slowed clinical decline(van Dyck et al.,2023). The recent positive results of anti-amyloid trials have brought back focus on the amyloid hypothesis through biochemical, genetic, and pharmacological approaches(Zhang, 2023).

关键词： Alzheimer inflammation hypothesis

Emerging role of A-kinase anchoring protein 5 signaling in reward circuit function

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Neural Regeneration Research 2025年第10期20卷 2913-2914页

作者： William j.Flerlage mark L.Dell’Acqua Brian m.Cox Fereshteh S.Nugent Uniformed Services University of the Health Sciences Department of Pharmacology and Molecular TherapeuticsBethesdaMDUSA Department of Pharmacology University of Colorado School of MedicineAnschutz Medical CampusAuroraCOUSA

There is a strong evidence supporting the hypothesis of synaptic dysfunction as a major contributor to neural circuit and network disruption underlying emotional and mood dysregulation in psychiatric disorders(Simmons et al.,2024).Diverse sets of distinct molecular signaling pathways converge on the synapse to regulate synaptogenesis,synaptic function,and synaptic plasticity in brain regions and circuits through complex interactions organized by numerous multivalent protein scaffolds,including the family of proteins known as A-kinase anchoring proteins(AKAPs).

关键词： function supporting

Synthesis of a New Class of Highly Functionalized Phosphorus Ylides Containing Heterocyclic Compounds

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Chinese journal of Chemistry 2012年第8期30卷 1893-1900页

作者： Shaabani Ahmad Keshipour Sajjad Aghaei morteza Khodabandeh m. Hassan zahedi mansour Department of Chemistry Shahid Beheshti University G. C. P. O. Box 19396-4716 Tehran Iran

The zwitterionic intermediate generated from the reaction of triphenylphosphine with electron deficient acety- lenic compounds was trapped by various NH acids. The synthesis resulted in a new class of highly functionalized heterocyclic compounds. Some of the reactions produced E and Z isomers. And the stability and transformation of them were studied by dynamic 1H NmR and density functional theory （DFT） calculations.

关键词： highly functionalized heterocyclic compounds phosphorus ylides triphenylphosphine DFT dynamic 1H NmR

The Synthesis and Characterization of Peach-Like ZnO

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Chinese Physics Letters 2012年第12期29卷 232-235页

作者： A.Kamalianfar S.A.Halim Siamak Pilban jahromi m.Navasery Fasih Ud Din K.P.Lim S.K.Chen j.A.m.zahedi Department of Physics Faculty of ScienceUniversity Putra Malaysia43400 UPM SerdangSelangorMalaysia Institute for mathematical Research University Putra Malaysia43400 UPM SerdangSelangorMalaysia Low Dimensional materials Research Center Department of PhysicsFaculty of ScienceUniversity of Malaya50603 Kuala LumpurMalaysia Department of Physics Karaj BranchIslamic Azad UniversityKarajIran Department of Physics Jahrom UniversityJahromIran

Peach-like ZnO microstructures are synthesized using vapor phase transport on mgO(001)substrates with a copper oxide(60 nm)buffer *** structure and morphology of the product are investigated using an x-ray diffractometer(XRD)and a field-emission scanning electron *** peaches have an average diameter of 3μm and a wurtzite *** study the optical properties,photoluminescence(PL)and Raman spectroscopy are employed.A strong UV emission at 380 nm in the PL spectra is observed,and a sharp and dominant peak at 437 cm^(-1) in the Raman spectrum can be assigned to the good crystallization of obtained *** addition,the growth mechanism of the peach-like ZnO structure is tentatively investigated based on the EDX analysis and growth time.

关键词： crystallization structure tentative

Nonlinear forced vibration in a subcritical regime of a porous functionally graded pipe conveying fluid with a retaining clip

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Applied mathematics and mechanics(English Edition) 2025年第1期46卷 101-122页

作者： m.GHOLAmI m.EFTEKHARI Department of mechanical Engineering Shahid Bahonar University of Kerman

This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGm) that conveys fluids and is equipped with a retaining clip, focusing on primary resonance and subcritical dynamics. The nonlinear governing equations for the FGm pipe are derived by the extended Hamilton's principle, and subsequently discretized through the application of the Galerkin *** direct method of multi-scales is then used to solve the derived equations. A thorough analysis of various parameters, including the clip stiffness, the power-law index, the porosity, and the clip location, is conducted to gain a comprehensive understanding of the system's nonlinear dynamics. Through the analysis of the first natural frequency, the study highlights the influence of the flow velocity and the clip stiffness, while the comparisons with metallic pipes emphasize the role of FGm composition. The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index, offering valuable insights into the system's nonlinear resonant behavior. Furthermore, the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness, revealing nuanced effects on the system response and resonance characteristics. This comprehensive analysis enhances the understanding of nonlinear behaviors in FGm porous pipes with a retaining clip, providing key insights for practical engineering applications in system design and optimization.

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microplastics in the atmosphere of Ahvaz City, Iran

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journal of Environmental Sciences 2023年第4期126卷 95-102页

作者： Sajjad Abbasi Neamatollah jaafarzadeh Amir zahedi maryam Ravanbakhsh Somayeh Abbaszadeh Andrew Turner Department of Earth Sciences College of ScienceShiraz UniversityShiraz 71454Iran Department of Radiochemistry and Environmental Chemistry Faculty of ChemistryMaria Curie-Skłodowska UniversityLublin 20-031Poland Environmental Technologies Research Center Ahvaz Jundishapur University of Medical SciencesAhvazIran Department of Environmental Health Engineering Shoushtar Faculty of Medical SciencesShoushtarIran Student Research Committee Ahvaz Jundishapur University of Medical SciencesAhvazIran School of Geography Earth and Environmental SciencesPlymouth UniversityPL48AAUK

Airborne particulate matter(Pm) with an aerodynamic size cutoff of 10 μm(Pm_(10)) has been collected using a high volume air sampler at two locations(urban and residential) in the city of Ahvaz, Iran, for sixteen 24-hour periods over four months(late summer to early winter).microplastics(mPs) in the Pm were isolated after sample digestion and were subsequently characterised by established techniques. All mPs sampled(n = 322) were of a fibrous nature,with polyethylene terephthalate, nylon and polypropylene being the dominant polymers and consistent with textiles and fabrics as the principal source. Despite a distinct seasonality(temperature and wind) over the study period, the abundance, size and colour of the fibres exhibited no clear temporal trend, and no clear differences were observed between the two sites. Concentrations of mPs ranged from none detected to about 0.017/m^(3)(median = 0.0065/m^(3)) and are at the low end of ranges reported in the recent literature for various urban and remote locations. While some mPs may have a local origin, the weathering of other mPs and their acquisition of extraneous geosolids and salts suggests that long-range transport is also important. Back-trajectory calculations indicate that regional sources are mainly to the north and west of Ahvaz, but a southerly, maritime source is also possible in late autumn. Although concentrations of mPs in the atmosphere are well below those encountered in indoor air, further studies are required to elucidate their potential ecological impacts.

关键词： microplastics Atmosphere Transport Fibres Polymers Ahvaz

The off-site implications of deforestation on sedimentation rates and pollution in Abkenar open water (Anzali Lagoon, Caspian Sea) using radionuclide techniques and sediment quality indices

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International journal of Sediment Research 2022年第3期37卷 370-382页

作者： mohammadreza Gharibreza mohammad Zaman mahmood Arabkhedri Shahriar Sobh-zahedi Soil Conservation and Watershed management Research Institute Agricultural Research Education and Extension Organization (AREEO) Soil and Water management & Crop Nutrition Section Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture International Atomic Energy AgencyVienna International Centre Guilan Agricultural and Natural Resources Research and Education Center AREEO

Abkenar open water(AOW) has a 35 km~2 distribution and is the largest part of the Anzali Lagoon in the southern coastal zone of the Caspian Sea. The effects of deforestation in the upstream basin of the AOW were assessed by measuring the rate of sedimentation, sediment contamination, and ecological risk for aquatic life and end-users using radioisotopes Cesium-137 and Lead-210. The chronology of the AOW sediment column was studied using the Constant Rate of Supply model. Correlations between environmental changes and the sedimentary regime of the study area highlight the contribution of the AOW authorized international and local wood harvesting companies pre-and-post 1950 in the catchment in terms of the rate of sediment supply and the influx of toxic metals. Historical evidence shows that two specific layers formed during World Wars I and II with the mean rates of 0.185 ± 0.04(±STD) and 0.32 ± 0.02 kg/(m·y), respectively. The highest influx of alkali elements and toxic metals(nickel, cadmium, lead, zinc, and copper) into the basin occurred in 1945. Two layers of gray mud(16-50 cm) and organic-rich dark loss mud(0-16 cm) correlated well with the programmed wood harvesting *** layers accumulated from 1953 to 2000 with a mean rate of 0.6 ± 0.2 and 2 ± 0.7 kg/(m~2·y). Thus,aquatic life and end-users have been exposed to moderate to extremely high levels of toxic metals and a moderate level of contamination since the 1950 s.

关键词： Abkenar open water Accumulation rate Anzali Lagoon Sediment contamination CRS model Radioisotopes

Neurogenesis dynamics in the olfactory bulb:deciphering circuitry organization, function, and adaptive plasticity

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Neural Regeneration Research 2025年第6期20卷 1565-1581页

作者： moawiah m.Naffaa Department of Psychology and Neuroscience Duke UniversityDurhamNCUSA Department of Cell Biology Duke University School of MedicineDurhamNCUSA

Adult neurogenesis persists after birth in the subventricular zone, with new neurons migrating to the granule cell layer and glomerular layers of the olfactory bulb, where they integrate into existing circuitry as inhibitory interneurons. The generation of these new neurons in the olfactory bulb supports both structural and functional plasticity, aiding in circuit remodeling triggered by memory and learning processes. However, the presence of these neurons, coupled with the cellular diversity within the olfactory bulb, presents an ongoing challenge in understanding its network organization and function. moreover,the continuous integration of new neurons in the olfactory bulb plays a pivotal role in regulating olfactory information processing. This adaptive process responds to changes in epithelial composition and contributes to the formation of olfactory memories by modulating cellular connectivity within the olfactory bulb and interacting intricately with higher-order brain regions. The role of adult neurogenesis in olfactory bulb functions remains a topic of debate. Nevertheless, the functionality of the olfactory bulb is intricately linked to the organization of granule cells around mitral and tufted cells. This organizational pattern significantly impacts output, network behavior, and synaptic plasticity, which are crucial for olfactory perception and memory. Additionally, this organization is further shaped by axon terminals originating from cortical and subcortical regions. Despite the crucial role of olfactory bulb in brain functions and behaviors related to olfaction, these complex and highly interconnected processes have not been comprehensively studied as a whole. Therefore, this manuscript aims to discuss our current understanding and explore how neural plasticity and olfactory neurogenesis contribute to enhancing the adaptability of the olfactory system. These mechanisms are thought to support olfactory learning and memory, potentially through increased

关键词： network adaptability neurogenesis neuronal communication olfactory bulb olfactory learning olfactory memory synaptic plasticity