Comparison of chevron and suspended-zipper braced steel frames

Suspended-zipper braced frame is a modified configuration of chevron braced frame in which zipper columns are added between story beams and a hat truss is attached between top two stories in order to redistribute the unbalanced vertical forces emerging following the brace buckling to avoid the use of deep beams. In this study, three- and nine-story chevron and suspended-zipper braced frames are analyzed to compare their seismic performances. The beams, columns, braces and zipper columns are modeled using nonlinear force-formulation frame elements and nonlinear geometric effects are included by utilizing corotational transformation. Nonlinear static analyses are performed until reaching a roof drift ratio of 3% and a set of twenty ground motion records scaled to match a 10% probability of exceedance in 50 years is used for nonlinear time-history analysis. The results appear to indicate that the lateral load capacity and drift demands for both low-rise chevron and suspended zipper braced frames are very similar; however, the mid-rise chevron braced frame has a better performance compared to the mid-rise suspended-zipper braced frame

The interference of a deep thermal system with a shallow aquifer and health risk assessment: the case of Sandikli (Afyonkarahisar) Basin, Turkey

WOS: 000371393400054A mixture of geothermal waters having high ionic concentration to cold water aquifers is caused to deterioration at irrigation and drinking water quality. The aim of this study is determine spreading and extending of pollution in cold groundwater with the contribution of geothermal waters in the Sandikli (Afyonkarahisar) basin. Hydrochemical facies of the waters is Ca-Mg-HCO3 and Ca-Mg-HCO3-SO4 in cold waters and Na-Ca-SO4-HCO3 in the geothermal waters, respectively. Ca2+ and HCO3 are dominant ions in cold waters, whereas those in geothermal waters are Na+ and SO42-. Shallow groundwaters have low ionic concentrations, while deep circulation waters have high ionic concentrations. The increases of T, EC, Na+, SO42-, Cl-, B, Al, As, Fe, Mn, Ni, F, U and NO3- parameters were determined in the cold groundwaters as locally due to hydrothermal contribution, waterrock interaction and anthropogenic effects in the Sandikli basin. As a related to groundwater usage, there are two different risks in the basin, human health risk (drinking water usage) and environmental risk (irrigation water usage). From the results of hazard index, it is verified that As is the main contaminant, and toxic human risk can be caused by ingestion of water in the basin.Scientific and Technical Research Council of Turkey (TUBITAK), Sandikli-Afyonkarahisar, Turkey [CAYDAG-110Y034]This study was financially supported by The Scientific and Technical Research Council of Turkey (TUBITAK) (Project No.: CAYDAG-110Y034-Project title: The study of hydrogeological, hydrogeochemical and isotopic of Hudai geothermal field and its vicinity, Sandikli-Afyonkarahisar, Turkey

Analyzing the Influence of Simultaneously Austenitization and Multi-Directional Boriding on the Surface and Subsurface of H13 Tool Steel

© 2022, ASM International.AISI H13 hot tool steel is very much famous for elevated temperature operations such as manufacturing of dies, molds, glass, and plastics. In order to extend the lifespan, surface hardening treatments such as nitriding, carburizing and boriding are as famous as austenitizing followed by dual tempering for overall core-structure enhancement. In this study, boriding (at 960 °C for 3 h) is combined with the conventionally used heat-treatments for the surface enhancement of H13 dies and substrates. Feasibility analysis, detailed surface and subsurface characterization, SEM, EDX and WDX analyses on the formed Fe2B and CrB rich coatings are performed. Results showed that faster cooling rates at the die openings, shrinkage of the middle sections of die and thermal mismatches between the hard layers and host material caused the formation of cracks parallel and perpendicular to the die orifices. Formation of ferrite pits, which were characterized with lower hardness, was witnessed in the vicinity of hard layers. This was attributed to accumulation of Si under the boride layers

Influences of human activities and agriculture on groundwater quality of Kayseri-Incesu-Dokuzpinar springs, central Anatolian part of Turkey

Human activities and agriculture have had direct and indirect effects on the rates of contamination of groundwater in the Incesu-Dokuzpinar spring area. Direct effects include dissolution and transport of excess quantities of fertilizers with associated materials and hydrological alterations related to irrigation and drainage. Indirect effects may include changes in water-rock reactions in soils and aquifers caused by increased concentrations of dissolved oxidants, protons, and major ions. Agricultural activities have directly or indirectly affected the concentrations of a large number of inorganic chemicals in groundwater, for example NO3, N2, Cl, SO42, H+, K, Mg, Ca, Fe, Cu, B, Pb, and Zn, as well as a wide variety of pesticides and other organic compounds. For reactive contaminants like NO3, it is recommended that a combination of hydrochemical and environmental-tracer analytical approaches might be required to resolve changing inputs from subsequent alterations as causes of concentration gradients in groundwater. The water type of Dokuzpinar springs is mainly Na-Mg-Ca-Cl-HCO3. Note that the water types of the springs were directly related to the hydrogeochemical properties of outcrops at the study area. Thus, the high concentration of Ca2+ and HCO3 is mainly related to the high CO2 contents in the marbles, whereas the high Na concentration arises from the existing syenite, volcanic ash, basalt, and clay units, although the İncesu-Dokuzpinar springs cover most of the drinking and irrigation water demands of this area. The high concentrations of NO3 and NaCl show that the area around the springs is continuously being contaminated by untreated sewage and agricultural wastes, especially during dry periods. Therefore, this approach is based on the vulnerability studies of the catchment area, determination of the transfer time of the pollutant, and the water-bearing formations of İncesu-Dokuzpinar springs. Vulnerability in this study is defined as the intrinsic hydrogeochemical characteristics of an aquifer, which may show the sensitivity of groundwater to be contaminated by different human activities

Estimation of environmental impacts on the water quality of İncesu-Dokuzpınar Springs in Kayseri, Turkey

Industrial and agricultural activities have directly or indirectly affected the concentrations of a large number of inorganic chemicals in groundwater, for example NO3, N2, Cl, SO4, H+, K, Mg, Ca, Fe, Cu, B, Pb and Zn, as well as a wide variety of pesticides and other organic compounds. For reactive contaminants like NO3, it is recommended that a combination of hydrochernical and environmental-tracer analytical approaches might be required to resolve changing inputs from subsequent alterations as causes of concentration gradients in groundwater. The water type of Incesu-Dokuzpinar Springs is mainly Na-MgCa-Cl-HCO3. Note that the water types of the Springs were directly related to the hydrogeochemical properties of outcrops at the study area. Thus, the high concentration of Ca+2 and HCO3 is mainly related to the high CO2 contents in the marbles, whereas the high Na concentration arises from the existing syenite, volcanic ash, basalt and clay units, although the ·Incesu-Dokuzpinar Springs cover most of the drinking and irrigation water demands at the study area. Therefore, relevant hydrogeochemical and statistical studies were carried out for estimating the mentioned environmental impacts on the water quality of ·Incesu-Dokuzpinar Springs. © Springer-Verlag 2004

Investigation of photodetector performance based on methylammonium lead halide perovskites/reduced graphene oxide heterostructure

The remarkable advancements achieved in the field of perovskite materials have spurred the development of photodetectors, playing a pivotal role in diverse optoelectronic applications. Among these, heterostructured perovskite-based photodetectors have emerged as a superior choice, surpassing the performance capabilities of their pure perovskite counterparts. This study presents the fabrication of an rGO/MAPbI3 heterostructured photodetector via the spin-coating technique. A comprehensive structural analysis of the device was conducted, encompassing X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy. Current–voltage (I–V) and capacitance–voltage (C–V) measurements, performed under various illumination conditions as well as in the absence of light, unequivocally demonstrate the photodiode characteristics of the device. The data reveal a direct correlation between illumination intensity and both current and capacitance, substantiating the photodetector’s responsiveness. Notably, the calculated photosensitivity values S (%) of the Al/Gra/p-Si device, measured under a reverse bias of − 2 V, exhibit a range, varying from 42,000 to 79,300%. Furthermore, observations suggest a decrease in series resistance with increasing illumination intensity, while the ideality factor and barrier height values show an opposite trend. In addition, frequency-dependent measurements divulge a decrease in capacitance as the frequency escalates. These findings can be elucidated through the interactions involving light-induced charges at the interface between the rGO oxide layer and the semiconductor, coupled with the dynamic fluctuations in quasi-Fermi levels within the state of equilibrium

Clinicopathological evaluation of Marjolin ulcers over two decades

Malignant changes arising on the previously traumatized or chronically inflamed skin are defined as Marjolin ulcers. They can develop on many different lesions but frequently they are detected on burn scars. Histopathologically, Marjolin ulcers are mostly diagnosed as squamous cell carcinoma and they need special attention when especially located on the lower extremities. In this study, 63 patients treated for Marjolin ulcers between January 2000 and March 2015 were evaluated according to etiology, histological differentiation, primary tumor size, patient age and anatomical localization. Medical records of these patients were reviewed retrospectively. Mean age was 49.7 years. Average interval between the first injury and carcinoma development was 37.9 years. Most frequent etiologic factor was burn scars with 82.5%. Foot was the most frequently affected site with 28.6% and scalp was the second most frequent localization with 25.4%. Squamous cell carcinomas were detected in 88.9% of the patients and basal cell carcinomas were detected in 11.1% of the patients. For treatment, excision and grafting was performed for 48 patients (76.2%), excision and local flaps were used for 10 patients (15.9%) and excision and free flaps were used for five patients (7.9%). Regional lymph node dissection was performed for 12 patients (19%). Average follow up period was 46.5 months. Local recurrences were detected in nine patients (14.3%). In conclusion, Marjolin ulcers are aggressive tumors that require special care. In order to prevent life threatening sequelas of this entity, it is important to know basic aspects of clinical progress, prognostic factors and treatment modalities