The post-collisional Cenozoic basic volcanic rocks in NE Turkey show temporal variations in whole-rock lithophile element and highly siderophile element(HSE)systematics that are mainly associated with the nature of su...The post-collisional Cenozoic basic volcanic rocks in NE Turkey show temporal variations in whole-rock lithophile element and highly siderophile element(HSE)systematics that are mainly associated with the nature of sub-continental lithospheric mantle(SCLM)sources and parental melt generation.So far,the traditional whole-rock lithophile geochemical data of these basic volcanic rocks have provided important constraints on the nature of SCLM sources.Integrated lithophile element and HSE geochemical data of these basic volcanic rocks also reveal the heterogeneity of the SCLM source,which is principally related to variable metasomatism resulting from previous subduction(s)and post-collisional mantle-crust interactions in an extensional setting.Lithophile element geochemical features suggest that the parental magmas have derived from metasomatized spinel-to garnet-bearing SCLM sources for Eocene and Miocene basic volcanic rocks with subduction signatures whereas originated from spinel-to garnet-bearing SCLM sources for Mio-Pliocene and Plio-Quaternary basaltic volcanic rocks without the subduction signature.Lithophile element and HSE geo-chemistry also reveal that Eocene and Miocene basic vol-canic rocks were affected by more pronounced crustal contamination than the basaltic volcanic rocks of Mio-Pliocene and Quaternary.Furthermore,the integrated lithophile element and HSE compositions of these basic volcanic rocks,together with the regional asymmetric lithospheric delamination model,reveal that the compositional variation(especially due to metasomatism)was significant temporally in the heterogeneity of the SCLM sources from which parental magmas formed during the Cenozoic era.展开更多
Mass movements are very common problems in the eastern Black Sea region of Turkey due to its climate conditions, geological, and geomorphological characteristics. High slope angle, weathering, dense rainfalls, and ant...Mass movements are very common problems in the eastern Black Sea region of Turkey due to its climate conditions, geological, and geomorphological characteristics. High slope angle, weathering, dense rainfalls, and anthropogenic impacts are generally reported as the most important triggering factors in the region. Following the portal slope excavations in the entrance section of Cankurtaran tunnel, located in the region, where the highly weathered andesitic tuff crops out, a circular toe failure occurred. The main target of the present study is to investigate the causes and occurrence mechanism of this failure and to determine the feasible remedial measures against it using finite element method(FEM) in four stages. These stages are slope stability analyses for pre-and postexcavation cases, and remediation design assessments for slope and tunnel. The results of the FEM-SSR analyses indicated that the insufficient initial support design and weathering of the andesitic tuffs are the main factors that caused the portal failure. After installing a rock retaining wall with jet grout columns and reinforced slope benching applications, the factor of safety increased from 0.83 to 2.80. In addition toslope stability evaluation, the Rock Mass Rating(RMR), Rock Mass Quality(Q) and New Austrian Tunneling Method(NATM) systems were also utilized as empirical methods to characterize the tunnel ground and to determine the tunnel support design. The performance of the suggested empirical support design, induced stress distributions and deformations were analyzed by means of numerical modelling. Finally, it was concluded that the recommended stabilization technique was essential for the dynamic long-term stability and prevents the effects of failure. Additionally, the FEM method gives useful and reasonably reliable results in evaluating the stability of cut slopes and tunnels excavated both in continuous and discontinuous rock masses.展开更多
Aptian is characterized by widespread deposition of organic-rich sediment.The Aptian bitumen limestone horizon,which is thin decimetre-thick sequences,locally crops out in the Kircaova area,Eastern Black Sea Region(Ea...Aptian is characterized by widespread deposition of organic-rich sediment.The Aptian bitumen limestone horizon,which is thin decimetre-thick sequences,locally crops out in the Kircaova area,Eastern Black Sea Region(Eastern Pontides).They are well correlated with Aptian bitumen limestone in the other Tethys Reams.They are proposed as episodes of increased organic matter.However,background factors controlling organic matter enrichment are poorly known.In this study,we present new inorganic geochemistry,including trace elements,rare earth elements(REE),redox-sensitive elements(RSE),stable-isotopes(δ~(18)O andδ~(13)C),and total organic carbon(TOC).We integrated new geochemical data with existing stratigraphy,paleontology,and organic chemistry data to provide new insight into the depositional environment and paleoclimate conditions during Aptian.The lacustrine bitumen limestone(LBL)samples have variedδ~(13)C(ave.-1.45‰)andδ~(18)O(ave.-4.50‰).They possess distinct REE patterns,with an average of REE(ave.14.45 ppm)and Y/Ho(ave.35)ratios.In addition,they have variable Nd/YbN(0.28-0.81;ave.0.56)and Ce/Ce*(0.68-0.97;ave.0.86),and relatively high Eu^(*)/Eu(1.23-1.53;ave.1.35).They display seawater signatures with reduced oxygen conditions.The enrichment in RSE(Mo,Cu,Ni,and Zn)and the low Mo/TOC(0.70-3.69;ave.2.41)support a certain degree of water restriction.The high Sr/Ba,Sr/Cu,Ga/Rb,and K/Al records of the LBL facies suggest hot house climatic conditions.The sedimentary environment was probably an isolated basin that is transformed from the marine basin.In addition to depositional conditions,the regional parameters such as the climate,increased run-off period,nutrient levels,alkalinity level,and dominant carbonate producers favored the enrichment in organic matter of LBL facies.Thus,extreme greenhouse palaeoclimate conditions have an important role in organic matter enrichment in the isolated basin.Our results are conformable with the published data from marine,semi-restricted basin,and lacustrine settings in the different parts of the Tethys margin.Thus,this approach provides the first insight into the Aptian greenhouse paleo-climate conditions of the Eastern Black Sea Region,NE Turkey.展开更多
Driftwood is one of the important physical components in mountainous rivers which causes severe hazards due to the clogging of bridges,culverts,and narrow sections during floods.Therefore,the understanding of driftwoo...Driftwood is one of the important physical components in mountainous rivers which causes severe hazards due to the clogging of bridges,culverts,and narrow sections during floods.Therefore,the understanding of driftwood dynamics and mitigation measures are crucial for managing wood in rivers.Open check dams are the most commonly used engineering measure for preventing driftwood from reaching downstream areas.Nevertheless,these open check dams frequently lose their sediment transport function when they are blocked by sediment and driftwood,especially during major flood events.This paper proposes a new type of open check dam for preventing from clogging.Thus,flume experiments were conducted to examine the influence of different types of open check dams on the characteristics of driftwood deposition.For the model with wood length(LWD)=16.5 cm,wood diameter(D)=15 mm,and wood number(N)=172,the highest trapping efficiency was observed with 90.1%and 87.2%retention rates for the classical debris flow breaker and curved footed open check dams,respectively.Laboratory tests showed that through this proposed design,woody debris blockage in a very short time was prevented from the accumulation of woods beside the dam.In addition to this,most of the sediment passed through the check dam and most of the driftwood got trapped.It can be briefly stated that the geometrical design of the structure plays an important role and can be chosen carefully to optimize trapping efficiency.By designing this type of open check dams in mountain river basins,it may provide a better understanding of the driftwood accumulation and basis for the optimal design of these structures.Further development of the solution proposed in this work can pave the way for designing different types of open check dams for effective flood management.展开更多
The key indication of a nation’s economic development and strength is the stock market.Inflation and economic expansion affect the volatility of the stock market.Given the multitude of factors,predicting stock prices...The key indication of a nation’s economic development and strength is the stock market.Inflation and economic expansion affect the volatility of the stock market.Given the multitude of factors,predicting stock prices is intrinsically challenging.Predicting the movement of stock price indexes is a difficult component of predicting financial time series.Accurately predicting the price movement of stocks can result in financial advantages for investors.Due to the complexity of stock market data,it is extremely challenging to create accurate forecasting models.Using machine learning and other algorithms to anticipate stock prices is an interesting area.The purpose of this article is to forecast stock market values to assist investors to make better informed and precise investing decisions.Statistics,Machine Learning(ML),Natural language processing(NLP),and sentiment analysis will be used to accomplish the study’s objectives.Using both qualitative and quantitative information,the study developed a hybrid model.The hybrid model has been handled with GANs.Based on the model’s predictions,a buy-or-sell trading strategy is offered.The conclusions of this study will assist investors in selecting the ideal choice while selling,holding,or buying shares.展开更多
The aim of this study was to examine the prognostic factors and treatment outcomes of cervical esophageal carcinoma(CEC)patients who underwent definitive chemoradiotherapy(CRT).The clinical data of 175 biopsyconfirmed...The aim of this study was to examine the prognostic factors and treatment outcomes of cervical esophageal carcinoma(CEC)patients who underwent definitive chemoradiotherapy(CRT).The clinical data of 175 biopsyconfirmed CEC patients treated with definitive CRT between April 2005 and September 2021 were retrospectively analyzed.The prognostic factors predicting overall survival(OS),progression-free survival(PFS),and local recurrence-free survival(LRFS)were assessed in uni-and multivariable analyses.The median age of the entire cohort was 56 years(range:26–87 years).All patients received definitive radiotherapy with a median total dose of 60 Gy,and 52%of the patients received cisplatin-based concurrent chemotherapy.The 2-year OS,PFS,and LRFS rates were 58.8%,46.9%,and 52.4%,respectively,with a median follow-up duration of 41.6 months.Patients’performance status,clinical nodal stage,tumor size,and treatment response were significant prognostic factors for OS,PFS,and LRFS in univariate analysis.Non-complete treatment response was an independent predictor for poor OS(HR=4.41,95%CI,2.78–7.00,p<0.001)and PFS(HR=4.28,95%CI,2.79–6.58,p<0.001),whereas poor performance score was a predictor for worse LRFS(HR=1.83,95%CI,1.12–2.98,p=0.02)in multivariable analysis.Fifty-two patients(29.7%)experienced grade II or higher toxicity.In this multicenter study,we demonstrated that definitive CRT is a safe and effective treatment for patients with CEC.Higher radiation doses were found to have no effect on treatment outcomes,but a better response to treatment and a better patient performance status did.展开更多
Fuel moisture content is an important variable for forest fires because it affects fuel ignition and fire behavior. In order to accurately predict fuel ignition potential, fuel moisture content must be assessed by eva...Fuel moisture content is an important variable for forest fires because it affects fuel ignition and fire behavior. In order to accurately predict fuel ignition potential, fuel moisture content must be assessed by evaluating fire spread, fireline intensity and fuel consumption.Our objective here is to model moisture content of surface fuels in normally stocked Calabrian pine(Pinus brutia Ten.) stands in relation to weather conditions, namely temperature, relative humidity, and wind speed in the Mugla province of Turkey. All surface fuels were categorized according to diameter classes and fuel types. Six fuel categories were defined: these were 0–0.3, 0.3–0.6, and0.6–1 cm diameter classes, and cone, surface litter, and duff. Plastic containers 15 9 20 cm in size with 1 9 1 mm mesh size were used. Samples were taken from 09:00 to19:00 h and weighed every 2 h with 0.01 g precision for10 days in August. At the end of the study, samples were taken to the laboratory, oven-dried at 105 °C for 24 h and weighed to obtain fuel-moisture contents. Weather measurements were taken from a fully automated weather station set up at the study site prior to the study. Correlation and regression analyses were carried out and models were developed to predict fuel moisture contents for desorption and adsorption phase for each fuel type categories. Practical fuel moisture prediction models were developed for dry period. Models were developed that performed well with reasonable accuracy, explaining up to 92 and 95.6%of the variability in fuel-moisture contents for desorption and adsorption phases, respectively. Validation of the models were conducted using an independent data set and known fuel moisture prediction models. The predictive power of the models was satisfactory with mean absolute error values being 1.48 and 1.02 for desorption and adsorption as compared to the 2.05 and 1.60 values for the Van Wagner's hourly litter moisture content prediction model. Results obtained in this study will be invaluable for fire management planning and modeling.展开更多
AA 6061 alloy and interstitial-free(IF)steel plates were joined by the friction stir welding(FSW)method,and the microstructure,mechanical properties,and biaxial stretch formability of the friction stir welded(FSWed)pa...AA 6061 alloy and interstitial-free(IF)steel plates were joined by the friction stir welding(FSW)method,and the microstructure,mechanical properties,and biaxial stretch formability of the friction stir welded(FSWed)parts were investigated.The results indicate that the FSWed parts showed optimum tensile strength during FSW with the 0.4-mm offset position of the tool.The Fe4Al13 intermetallic compound formed in the defect-free intersection of AA 6061 and IF-steel plates during FSW.The hardness of the IF-steel part of the FSWed region increased almost 90%relative to its initial hardness of HV0.2 105.The tensile and yield strengths of FSWed regions were approximately 170 MPa and 145 MPa,respectively.According to the formability tests,the Erichsen Index(EI)of the IF-steel,AA 6061,and the FSWed samples were determined to be 2.9 mm,1.9 mm,and 2.1 mm,respectively.The EI of the FSWed sample was almost the same as that of the AA 6061 alloy.However,it decreased compared with that of the IF-steel.The force at EI(FEI)was approximately 1180 N for the FSWed condition.This value is approximately 70%higher than that of AA 6061 alloy.展开更多
The higher frequency of varicocele in men with infertility has drawn attention and resulted in increased research at the molecular level towards treatments. The aim of this study was to investigate the role of tumor n...The higher frequency of varicocele in men with infertility has drawn attention and resulted in increased research at the molecular level towards treatments. The aim of this study was to investigate the role of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and its receptors in varicocele-induced testicular dysfunction in an experimental rat model. The rats were divided into three groups: control, sham and varicocele. Varicoceles in rats were induced by partial ligation of the left renal vein and left testes. The rats were analyzed 13 weeks after surgery. The degree of DNA fragmentation within cells in the testis was determined using terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (TUNEL) assay. Tubule degeneration was evaluated using the Johnsen score. The expression of TRAIL and its receptors was detected by immunohistochemical and Western blotting techniques. The apoptotic index, Johnsen score and the expression of TRAIL and TRAIL receptors were examined. The data are presented as the mean-.+s.d, and were analyzed using computer software. The KruskaI-Wallis and Dunn's multiple comparison tests were used in the statistical analyses. The germ cell apoptotic index was increased in rats with varicoceles when compared with the sham and control groups (P=0.0031). The Johnsen score was significantly decreased in the varicocele group when compared with the sham and control groups (P〈O.O001). Immunohistochemical and Western blotting analyses showed that after varicocele induction, the expression of TRAIL-R1 and TRAIL-R4 in germ cells was increased and the expression of TRAIL-R2 was decreased. There are no significant differences among the groups in terms of TRAIL and TRAIL-R3 receptor expression. The results of this study indicate that TRAIL and its receptors may have a potential role in the pathogenesis of varicocele-induced testicular dysfunction.展开更多
Stearic acid (67.83℃) and myristic acid (52.32℃) have high melting temperatures that can limit their use as phase change material (PCM) in low temperature solar heating applications such as solar space and greenhous...Stearic acid (67.83℃) and myristic acid (52.32℃) have high melting temperatures that can limit their use as phase change material (PCM) in low temperature solar heating applications such as solar space and greenhouse heating in regard to climatic requirements. However, their melting temperatures can be adjusted to a suitable value by preparing a eutectic mixture of the myristic acid (MA) and the stearic acid (SA). In the present study, the thermal analysis based on differential scanning calorimetry (DSC) technique shows that the mixture of myristic acid (MA) and stearic acid (SA) in the respective composition (by mass) of 64% and 36% forms a eutectic mixture having melting temperature of 44.13℃ and the latent heat of fusion of 182.4J·g-1. The thermal energy storage characteristics of the MA-SA eutectic mixture filled in the annulus of two concentric pipes were also experimentally established. The heat recovery rate and heat charging/discharging fractions were determined with respect to the change in the mass flow rate and the inlet temperature of heat transfer fluid. Based on the results obtained by DSC analysis and by the heat charg- ing/discharging processes of the PCM, it can be concluded that the MA-SA eutectic mixture is a potential material for low temperature thermal energy storage applications in terms of its thermo-physical and thermal characteristics.展开更多
The Kop ophiolite in NE Turkey,representing a forearc fragment of Neo-Tethys ocean,mainly consists of a paleoMoho transition zone(MTZ)and a harzburgitic upper mantle unit.The Kop MTZ locally contains cumulate
The effects of bacterial strain, salinity and pH on the bioleaching of a complex ore using mesophilic and extremely thermophilic bacteria were investigated and the statistical analysis of the results was performed usi...The effects of bacterial strain, salinity and pH on the bioleaching of a complex ore using mesophilic and extremely thermophilic bacteria were investigated and the statistical analysis of the results was performed using ERGUN’s test. The extreme thermophiles were shown to display superior kinetics of dissolution of zinc compared with the mesophiles as confirmed by the statistical analysis. Bioleaching performance of the extreme thermophiles is found to improve in response to the increase in acidity (pH from 2.0 to 1.0) whilst the activity of the mesophiles is adversely affected by decreasing pH. Statistical analysis of the bioleaching data indicates that the effect of pH is insignificant in the range of pH 1.0-1.2 for the extreme thermophiles and pH 1.4-2.0 for the mesophiles. Salinity is shown to have a suppressing effect on the mesophiles. However, the extreme thermophiles appear to be halophilic in character as they could operate efficiently under saline conditions (1%-4%Cl- (w/v)).展开更多
The amenability of a refractory ore to the extraction of gold and silver by cyanide leaching was investigated. Diagnostic leaching tests were also performed to shed light on the refractory characteristics of ore. The ...The amenability of a refractory ore to the extraction of gold and silver by cyanide leaching was investigated. Diagnostic leaching tests were also performed to shed light on the refractory characteristics of ore. The leaching tests show that the extraction of gold and silver is consistently low, i.e. ≤47% and ≤19.2%, respectively, over a leaching period of 24 h. Even fine grinding (e.g. <38 μm) does not improve the recovery of gold and silver. Diagnostic leaching approach provides information into the cause of the refractoriness of the ore. The findings suggest that the refractoriness is induced by the dissemination and encapsulation of the very fine gold and silver particles largely in the carbonates, oxides and sulfides and, to a small extent, with silicates present in the ore matrix. These findings highlight the practical importance of diagnostic leaching for the understanding of the refractory characteristic of such an ore and for the identification of possible pretreatment options to overcome its refractoriness prior to cyanide leaching.展开更多
The Eastern Pontides orogenic belt in the Black Sea region of Turkey offers a critical window to plate kinematics and subduction polarity during the closure of the Paleotethys. Here we provide a brief synthesis on rec...The Eastern Pontides orogenic belt in the Black Sea region of Turkey offers a critical window to plate kinematics and subduction polarity during the closure of the Paleotethys. Here we provide a brief synthesis on recent information from this belt. We infer a southward subduction for the origin of the Eastern Pontides orogenic belt and its associated late Mesozoic--Cenozoic magmatism based on clear spatial and temporal variations in Late Cretaceous and Cenozoic arc magmatism, together with the exis- tence of a prominent south-dipping reverse fault system along the entire southern coast of the Black Sea. Our model is at variance with some recent proposals favoring a northward subduction polarity, and illus- trates the importance of arc magmatism in evaluating the geodynamic milieu associated with convergent margin orocesses.展开更多
First and Second Law analyses were conducted to evaluate the performance of a closed latent heat thermal energy storage (LHTES) system employing calcium chloride hexahydrate (CaCl2-6H2O).The First and the Second Laws ...First and Second Law analyses were conducted to evaluate the performance of a closed latent heat thermal energy storage (LHTES) system employing calcium chloride hexahydrate (CaCl2-6H2O).The First and the Second Laws of thermodynamics were applied to the system from viewpoint of energy and exergy analyses,respectively. The energy storage tank in the system is neither fully mixed nor fully stratified. It may be considered as semithermal stratified. Experiments that include both charging and discharging periods were performed on sunny winter days in 1996. The energy and exergy variations and the overall energy and exergy efficiencies of the closed LHTES system were calculated for the complete charging and discharging cycle of the selected fifteen clear-sky winter days. Mean energy and exergy efficiencies were found to be 55.20% and 34.83%, respectively.展开更多
This paper aims at reporting the results of a number of drag pick cutting tests on selected igneous rock samples to compare the experimentally determined maximum cutting force (FC) values with theoreti- cally estima...This paper aims at reporting the results of a number of drag pick cutting tests on selected igneous rock samples to compare the experimentally determined maximum cutting force (FC) values with theoreti- cally estimated ones. First, a review on theoretical rock cutting models proposed for both chisel and conical picks was presented in detail. Experimental study consists of both chisel and conical pick cutting tests in unrelieved (single-pick) cutting mode with varying cutting depths. FC' values were determined from experimental results, and theoretical models were utilized to compute FC for all cutting conditions. Computed and experimentally determined F( data were then compared for a referenced cutting depth. It is shown that the theoretical models might overestimate or underestimate FC' and cannot give reliable results. Finally, explanations for these mismatches were presented.展开更多
文摘The post-collisional Cenozoic basic volcanic rocks in NE Turkey show temporal variations in whole-rock lithophile element and highly siderophile element(HSE)systematics that are mainly associated with the nature of sub-continental lithospheric mantle(SCLM)sources and parental melt generation.So far,the traditional whole-rock lithophile geochemical data of these basic volcanic rocks have provided important constraints on the nature of SCLM sources.Integrated lithophile element and HSE geochemical data of these basic volcanic rocks also reveal the heterogeneity of the SCLM source,which is principally related to variable metasomatism resulting from previous subduction(s)and post-collisional mantle-crust interactions in an extensional setting.Lithophile element geochemical features suggest that the parental magmas have derived from metasomatized spinel-to garnet-bearing SCLM sources for Eocene and Miocene basic volcanic rocks with subduction signatures whereas originated from spinel-to garnet-bearing SCLM sources for Mio-Pliocene and Plio-Quaternary basaltic volcanic rocks without the subduction signature.Lithophile element and HSE geo-chemistry also reveal that Eocene and Miocene basic vol-canic rocks were affected by more pronounced crustal contamination than the basaltic volcanic rocks of Mio-Pliocene and Quaternary.Furthermore,the integrated lithophile element and HSE compositions of these basic volcanic rocks,together with the regional asymmetric lithospheric delamination model,reveal that the compositional variation(especially due to metasomatism)was significant temporally in the heterogeneity of the SCLM sources from which parental magmas formed during the Cenozoic era.
文摘Mass movements are very common problems in the eastern Black Sea region of Turkey due to its climate conditions, geological, and geomorphological characteristics. High slope angle, weathering, dense rainfalls, and anthropogenic impacts are generally reported as the most important triggering factors in the region. Following the portal slope excavations in the entrance section of Cankurtaran tunnel, located in the region, where the highly weathered andesitic tuff crops out, a circular toe failure occurred. The main target of the present study is to investigate the causes and occurrence mechanism of this failure and to determine the feasible remedial measures against it using finite element method(FEM) in four stages. These stages are slope stability analyses for pre-and postexcavation cases, and remediation design assessments for slope and tunnel. The results of the FEM-SSR analyses indicated that the insufficient initial support design and weathering of the andesitic tuffs are the main factors that caused the portal failure. After installing a rock retaining wall with jet grout columns and reinforced slope benching applications, the factor of safety increased from 0.83 to 2.80. In addition toslope stability evaluation, the Rock Mass Rating(RMR), Rock Mass Quality(Q) and New Austrian Tunneling Method(NATM) systems were also utilized as empirical methods to characterize the tunnel ground and to determine the tunnel support design. The performance of the suggested empirical support design, induced stress distributions and deformations were analyzed by means of numerical modelling. Finally, it was concluded that the recommended stabilization technique was essential for the dynamic long-term stability and prevents the effects of failure. Additionally, the FEM method gives useful and reasonably reliable results in evaluating the stability of cut slopes and tunnels excavated both in continuous and discontinuous rock masses.
文摘Aptian is characterized by widespread deposition of organic-rich sediment.The Aptian bitumen limestone horizon,which is thin decimetre-thick sequences,locally crops out in the Kircaova area,Eastern Black Sea Region(Eastern Pontides).They are well correlated with Aptian bitumen limestone in the other Tethys Reams.They are proposed as episodes of increased organic matter.However,background factors controlling organic matter enrichment are poorly known.In this study,we present new inorganic geochemistry,including trace elements,rare earth elements(REE),redox-sensitive elements(RSE),stable-isotopes(δ~(18)O andδ~(13)C),and total organic carbon(TOC).We integrated new geochemical data with existing stratigraphy,paleontology,and organic chemistry data to provide new insight into the depositional environment and paleoclimate conditions during Aptian.The lacustrine bitumen limestone(LBL)samples have variedδ~(13)C(ave.-1.45‰)andδ~(18)O(ave.-4.50‰).They possess distinct REE patterns,with an average of REE(ave.14.45 ppm)and Y/Ho(ave.35)ratios.In addition,they have variable Nd/YbN(0.28-0.81;ave.0.56)and Ce/Ce*(0.68-0.97;ave.0.86),and relatively high Eu^(*)/Eu(1.23-1.53;ave.1.35).They display seawater signatures with reduced oxygen conditions.The enrichment in RSE(Mo,Cu,Ni,and Zn)and the low Mo/TOC(0.70-3.69;ave.2.41)support a certain degree of water restriction.The high Sr/Ba,Sr/Cu,Ga/Rb,and K/Al records of the LBL facies suggest hot house climatic conditions.The sedimentary environment was probably an isolated basin that is transformed from the marine basin.In addition to depositional conditions,the regional parameters such as the climate,increased run-off period,nutrient levels,alkalinity level,and dominant carbonate producers favored the enrichment in organic matter of LBL facies.Thus,extreme greenhouse palaeoclimate conditions have an important role in organic matter enrichment in the isolated basin.Our results are conformable with the published data from marine,semi-restricted basin,and lacustrine settings in the different parts of the Tethys margin.Thus,this approach provides the first insight into the Aptian greenhouse paleo-climate conditions of the Eastern Black Sea Region,NE Turkey.
文摘Driftwood is one of the important physical components in mountainous rivers which causes severe hazards due to the clogging of bridges,culverts,and narrow sections during floods.Therefore,the understanding of driftwood dynamics and mitigation measures are crucial for managing wood in rivers.Open check dams are the most commonly used engineering measure for preventing driftwood from reaching downstream areas.Nevertheless,these open check dams frequently lose their sediment transport function when they are blocked by sediment and driftwood,especially during major flood events.This paper proposes a new type of open check dam for preventing from clogging.Thus,flume experiments were conducted to examine the influence of different types of open check dams on the characteristics of driftwood deposition.For the model with wood length(LWD)=16.5 cm,wood diameter(D)=15 mm,and wood number(N)=172,the highest trapping efficiency was observed with 90.1%and 87.2%retention rates for the classical debris flow breaker and curved footed open check dams,respectively.Laboratory tests showed that through this proposed design,woody debris blockage in a very short time was prevented from the accumulation of woods beside the dam.In addition to this,most of the sediment passed through the check dam and most of the driftwood got trapped.It can be briefly stated that the geometrical design of the structure plays an important role and can be chosen carefully to optimize trapping efficiency.By designing this type of open check dams in mountain river basins,it may provide a better understanding of the driftwood accumulation and basis for the optimal design of these structures.Further development of the solution proposed in this work can pave the way for designing different types of open check dams for effective flood management.
文摘The key indication of a nation’s economic development and strength is the stock market.Inflation and economic expansion affect the volatility of the stock market.Given the multitude of factors,predicting stock prices is intrinsically challenging.Predicting the movement of stock price indexes is a difficult component of predicting financial time series.Accurately predicting the price movement of stocks can result in financial advantages for investors.Due to the complexity of stock market data,it is extremely challenging to create accurate forecasting models.Using machine learning and other algorithms to anticipate stock prices is an interesting area.The purpose of this article is to forecast stock market values to assist investors to make better informed and precise investing decisions.Statistics,Machine Learning(ML),Natural language processing(NLP),and sentiment analysis will be used to accomplish the study’s objectives.Using both qualitative and quantitative information,the study developed a hybrid model.The hybrid model has been handled with GANs.Based on the model’s predictions,a buy-or-sell trading strategy is offered.The conclusions of this study will assist investors in selecting the ideal choice while selling,holding,or buying shares.
文摘The aim of this study was to examine the prognostic factors and treatment outcomes of cervical esophageal carcinoma(CEC)patients who underwent definitive chemoradiotherapy(CRT).The clinical data of 175 biopsyconfirmed CEC patients treated with definitive CRT between April 2005 and September 2021 were retrospectively analyzed.The prognostic factors predicting overall survival(OS),progression-free survival(PFS),and local recurrence-free survival(LRFS)were assessed in uni-and multivariable analyses.The median age of the entire cohort was 56 years(range:26–87 years).All patients received definitive radiotherapy with a median total dose of 60 Gy,and 52%of the patients received cisplatin-based concurrent chemotherapy.The 2-year OS,PFS,and LRFS rates were 58.8%,46.9%,and 52.4%,respectively,with a median follow-up duration of 41.6 months.Patients’performance status,clinical nodal stage,tumor size,and treatment response were significant prognostic factors for OS,PFS,and LRFS in univariate analysis.Non-complete treatment response was an independent predictor for poor OS(HR=4.41,95%CI,2.78–7.00,p<0.001)and PFS(HR=4.28,95%CI,2.79–6.58,p<0.001),whereas poor performance score was a predictor for worse LRFS(HR=1.83,95%CI,1.12–2.98,p=0.02)in multivariable analysis.Fifty-two patients(29.7%)experienced grade II or higher toxicity.In this multicenter study,we demonstrated that definitive CRT is a safe and effective treatment for patients with CEC.Higher radiation doses were found to have no effect on treatment outcomes,but a better response to treatment and a better patient performance status did.
基金supported by The Scientific and Technological Research Council of Turkey(TUBITAK),Project No:TOVAG–112O809
文摘Fuel moisture content is an important variable for forest fires because it affects fuel ignition and fire behavior. In order to accurately predict fuel ignition potential, fuel moisture content must be assessed by evaluating fire spread, fireline intensity and fuel consumption.Our objective here is to model moisture content of surface fuels in normally stocked Calabrian pine(Pinus brutia Ten.) stands in relation to weather conditions, namely temperature, relative humidity, and wind speed in the Mugla province of Turkey. All surface fuels were categorized according to diameter classes and fuel types. Six fuel categories were defined: these were 0–0.3, 0.3–0.6, and0.6–1 cm diameter classes, and cone, surface litter, and duff. Plastic containers 15 9 20 cm in size with 1 9 1 mm mesh size were used. Samples were taken from 09:00 to19:00 h and weighed every 2 h with 0.01 g precision for10 days in August. At the end of the study, samples were taken to the laboratory, oven-dried at 105 °C for 24 h and weighed to obtain fuel-moisture contents. Weather measurements were taken from a fully automated weather station set up at the study site prior to the study. Correlation and regression analyses were carried out and models were developed to predict fuel moisture contents for desorption and adsorption phase for each fuel type categories. Practical fuel moisture prediction models were developed for dry period. Models were developed that performed well with reasonable accuracy, explaining up to 92 and 95.6%of the variability in fuel-moisture contents for desorption and adsorption phases, respectively. Validation of the models were conducted using an independent data set and known fuel moisture prediction models. The predictive power of the models was satisfactory with mean absolute error values being 1.48 and 1.02 for desorption and adsorption as compared to the 2.05 and 1.60 values for the Van Wagner's hourly litter moisture content prediction model. Results obtained in this study will be invaluable for fire management planning and modeling.
基金supported by “The World Academy of Sciences(TWAS)under the Visiting Researchers program of TWAS-UNESCO Associateship Scheme(No.3240290077)”
文摘AA 6061 alloy and interstitial-free(IF)steel plates were joined by the friction stir welding(FSW)method,and the microstructure,mechanical properties,and biaxial stretch formability of the friction stir welded(FSWed)parts were investigated.The results indicate that the FSWed parts showed optimum tensile strength during FSW with the 0.4-mm offset position of the tool.The Fe4Al13 intermetallic compound formed in the defect-free intersection of AA 6061 and IF-steel plates during FSW.The hardness of the IF-steel part of the FSWed region increased almost 90%relative to its initial hardness of HV0.2 105.The tensile and yield strengths of FSWed regions were approximately 170 MPa and 145 MPa,respectively.According to the formability tests,the Erichsen Index(EI)of the IF-steel,AA 6061,and the FSWed samples were determined to be 2.9 mm,1.9 mm,and 2.1 mm,respectively.The EI of the FSWed sample was almost the same as that of the AA 6061 alloy.However,it decreased compared with that of the IF-steel.The force at EI(FEI)was approximately 1180 N for the FSWed condition.This value is approximately 70%higher than that of AA 6061 alloy.
基金The Scientific and Technological Research Council of Turkey (TUBITAK) for providing financial support via a S&T research project (Project No. 213M492)
文摘The higher frequency of varicocele in men with infertility has drawn attention and resulted in increased research at the molecular level towards treatments. The aim of this study was to investigate the role of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and its receptors in varicocele-induced testicular dysfunction in an experimental rat model. The rats were divided into three groups: control, sham and varicocele. Varicoceles in rats were induced by partial ligation of the left renal vein and left testes. The rats were analyzed 13 weeks after surgery. The degree of DNA fragmentation within cells in the testis was determined using terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (TUNEL) assay. Tubule degeneration was evaluated using the Johnsen score. The expression of TRAIL and its receptors was detected by immunohistochemical and Western blotting techniques. The apoptotic index, Johnsen score and the expression of TRAIL and TRAIL receptors were examined. The data are presented as the mean-.+s.d, and were analyzed using computer software. The KruskaI-Wallis and Dunn's multiple comparison tests were used in the statistical analyses. The germ cell apoptotic index was increased in rats with varicoceles when compared with the sham and control groups (P=0.0031). The Johnsen score was significantly decreased in the varicocele group when compared with the sham and control groups (P〈O.O001). Immunohistochemical and Western blotting analyses showed that after varicocele induction, the expression of TRAIL-R1 and TRAIL-R4 in germ cells was increased and the expression of TRAIL-R2 was decreased. There are no significant differences among the groups in terms of TRAIL and TRAIL-R3 receptor expression. The results of this study indicate that TRAIL and its receptors may have a potential role in the pathogenesis of varicocele-induced testicular dysfunction.
基金Supported by the Research Fund of Gaziosmanpasa University (No.2003/42).
文摘Stearic acid (67.83℃) and myristic acid (52.32℃) have high melting temperatures that can limit their use as phase change material (PCM) in low temperature solar heating applications such as solar space and greenhouse heating in regard to climatic requirements. However, their melting temperatures can be adjusted to a suitable value by preparing a eutectic mixture of the myristic acid (MA) and the stearic acid (SA). In the present study, the thermal analysis based on differential scanning calorimetry (DSC) technique shows that the mixture of myristic acid (MA) and stearic acid (SA) in the respective composition (by mass) of 64% and 36% forms a eutectic mixture having melting temperature of 44.13℃ and the latent heat of fusion of 182.4J·g-1. The thermal energy storage characteristics of the MA-SA eutectic mixture filled in the annulus of two concentric pipes were also experimentally established. The heat recovery rate and heat charging/discharging fractions were determined with respect to the change in the mass flow rate and the inlet temperature of heat transfer fluid. Based on the results obtained by DSC analysis and by the heat charg- ing/discharging processes of the PCM, it can be concluded that the MA-SA eutectic mixture is a potential material for low temperature thermal energy storage applications in terms of its thermo-physical and thermal characteristics.
文摘The Kop ophiolite in NE Turkey,representing a forearc fragment of Neo-Tethys ocean,mainly consists of a paleoMoho transition zone(MTZ)and a harzburgitic upper mantle unit.The Kop MTZ locally contains cumulate
文摘The effects of bacterial strain, salinity and pH on the bioleaching of a complex ore using mesophilic and extremely thermophilic bacteria were investigated and the statistical analysis of the results was performed using ERGUN’s test. The extreme thermophiles were shown to display superior kinetics of dissolution of zinc compared with the mesophiles as confirmed by the statistical analysis. Bioleaching performance of the extreme thermophiles is found to improve in response to the increase in acidity (pH from 2.0 to 1.0) whilst the activity of the mesophiles is adversely affected by decreasing pH. Statistical analysis of the bioleaching data indicates that the effect of pH is insignificant in the range of pH 1.0-1.2 for the extreme thermophiles and pH 1.4-2.0 for the mesophiles. Salinity is shown to have a suppressing effect on the mesophiles. However, the extreme thermophiles appear to be halophilic in character as they could operate efficiently under saline conditions (1%-4%Cl- (w/v)).
文摘The amenability of a refractory ore to the extraction of gold and silver by cyanide leaching was investigated. Diagnostic leaching tests were also performed to shed light on the refractory characteristics of ore. The leaching tests show that the extraction of gold and silver is consistently low, i.e. ≤47% and ≤19.2%, respectively, over a leaching period of 24 h. Even fine grinding (e.g. <38 μm) does not improve the recovery of gold and silver. Diagnostic leaching approach provides information into the cause of the refractoriness of the ore. The findings suggest that the refractoriness is induced by the dissemination and encapsulation of the very fine gold and silver particles largely in the carbonates, oxides and sulfides and, to a small extent, with silicates present in the ore matrix. These findings highlight the practical importance of diagnostic leaching for the understanding of the refractory characteristic of such an ore and for the identification of possible pretreatment options to overcome its refractoriness prior to cyanide leaching.
基金The Scientific and Technological Research Council of Turkey(TUBITAK-Grant 108Y309)
文摘The Eastern Pontides orogenic belt in the Black Sea region of Turkey offers a critical window to plate kinematics and subduction polarity during the closure of the Paleotethys. Here we provide a brief synthesis on recent information from this belt. We infer a southward subduction for the origin of the Eastern Pontides orogenic belt and its associated late Mesozoic--Cenozoic magmatism based on clear spatial and temporal variations in Late Cretaceous and Cenozoic arc magmatism, together with the exis- tence of a prominent south-dipping reverse fault system along the entire southern coast of the Black Sea. Our model is at variance with some recent proposals favoring a northward subduction polarity, and illus- trates the importance of arc magmatism in evaluating the geodynamic milieu associated with convergent margin orocesses.
文摘First and Second Law analyses were conducted to evaluate the performance of a closed latent heat thermal energy storage (LHTES) system employing calcium chloride hexahydrate (CaCl2-6H2O).The First and the Second Laws of thermodynamics were applied to the system from viewpoint of energy and exergy analyses,respectively. The energy storage tank in the system is neither fully mixed nor fully stratified. It may be considered as semithermal stratified. Experiments that include both charging and discharging periods were performed on sunny winter days in 1996. The energy and exergy variations and the overall energy and exergy efficiencies of the closed LHTES system were calculated for the complete charging and discharging cycle of the selected fifteen clear-sky winter days. Mean energy and exergy efficiencies were found to be 55.20% and 34.83%, respectively.
文摘This paper aims at reporting the results of a number of drag pick cutting tests on selected igneous rock samples to compare the experimentally determined maximum cutting force (FC) values with theoreti- cally estimated ones. First, a review on theoretical rock cutting models proposed for both chisel and conical picks was presented in detail. Experimental study consists of both chisel and conical pick cutting tests in unrelieved (single-pick) cutting mode with varying cutting depths. FC' values were determined from experimental results, and theoretical models were utilized to compute FC for all cutting conditions. Computed and experimentally determined F( data were then compared for a referenced cutting depth. It is shown that the theoretical models might overestimate or underestimate FC' and cannot give reliable results. Finally, explanations for these mismatches were presented.