ARTICLE | doi:10.20944/preprints202201.0088.v1
Subject: Materials Science, General Materials Science Keywords: High-temperature superconductivity; critical temperature
Online: 6 January 2022 (12:36:26 CET)
The dependence of the critical temperature $T_c$ of high-temperature superconductors of various families on their composition and structure is proposed. A clear dependence of the critical temperature of high-temperature superconductors (hydrides, Hg- and Y-based cuprates) on the serial number of the constituent elements, their valence and crystal lattice structure has been revealed. For cuprates, it is shown that it is possible to obtain even higher temperatures of superconducting transitions at normal pressure by implanting mercury atoms into the crystal lattice of cuprate.
ARTICLE | doi:10.20944/preprints201703.0021.v1
Subject: Earth Sciences, Environmental Sciences Keywords: maximum surface air temperature; land surface temperature; statistical modeling; MODIS
Online: 3 March 2017 (08:38:19 CET)
Daily maximum surface air temperature (Tamax) is a crucial factor for understanding complex land surface processes under rapid climate change. Remote detection of Tamax has widely relied on the empirical relationship between air temperature and land surface temperature (LST), a product derived from remote sensing. However, little is known about how such a relationship is affected by the high heterogeneity in landscapes and dynamics in seasonality. This study aims to advance our understanding of the roles of land cover and seasonal variation in the estimation of Tamax using the MODIS (Moderate Resolution Imaging Spectroradiometer) LST product. We developed statistical models to link Tamax and LST in the middle and lower reaches of the Yangtze River in China for five major land-cover types (i.e., forest, shrub, water, impervious surface, cropland, and grassland) and two seasons (i.e., growing season and non-growing season). Results show that the performance of modeling the Tamax-LST relationship was highly dependent on land cover and seasonal variation. Estimating Tamax over grasslands and water bodies achieved superior performance; while uncertainties were high over forested lands that contained extensive heterogeneity in species types, plant structure, and topography. We further found that all the land-cover specific models developed for the plant non-growing season outperformed the corresponding models developed for the growing season. Discrepancies in model performance mainly occurred in the vegetated areas (forest, cropland, and shrub), suggesting an important role of plant phenology in defining the statistical relationship between Tamax and LST. For impervious surfaces, the challenge of capturing the high spatial heterogeneity in urban settings using the low-resolution MODIS data made Tamax estimation a difficult task, which was especially true in the growing season.
REVIEW | doi:10.20944/preprints202005.0070.v2
Subject: Life Sciences, Virology Keywords: Covid; covid-19; sars-cov-2; temperature; heat; body temperature; air temperature; viral decay; viral stability; transmission; severity; virology; thermodynamics
Online: 6 September 2021 (13:23:23 CEST)
Currently available data are consistent with increased severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication at temperatures encountered in the upper airways (25–33°C when breathing room temperature air, 25°C) compared to those in the lower airways (37°C). One factor that may contribute to more rapid viral growth in the upper airways is the exponential increase in SARS-CoV-2 stability that occurs with reductions in temperature, as measured in vitro. Because SARS-CoV-2 frequently initiates infection in the upper airways before spreading through the body, increased upper airway viral growth early in the disease course may result in more rapid progression of disease and potentially contribute to more severe outcomes. Similarly, higher SARS-CoV-2 viral titer in the upper airways likely supports more efficient transmission. Conversely, the possible significance of air temperature to upper airway viral growth suggests that prolonged delivery of heated air might represent a preventative measure and prophylactic treatment for coronavirus disease 2019.
ARTICLE | doi:10.20944/preprints202207.0440.v1
Subject: Earth Sciences, Environmental Sciences Keywords: climate change; drought; water deficit index; infrared observations; satellite; remote sensing; surface temperature; air temperature; humidity; dew point temperature
Online: 29 July 2022 (02:36:22 CEST)
The boreal Hemisphere has been experiencing increasing extreme hot and dry conditions over the past few decades, consistent with anthropogenic climate change expectations. The continental extension of the phenomenon calls for tools and techniques capable of monitoring the global to regional scales. In this context, the satellite is the only system that can satisfy the need for global coverage. The main objective we have addressed in the present paper is the capability of infrared satellite observations helping to monitor the vegetation stress due to increasing drought and heatwaves in summer. We have designed and implemented a new water deficit index (wdi) that exploits satellite observations in the infrared to retrieve humidity, air temperature, and surface temperature simultaneously. These three parameters are combined to provide the water deficit index. The index has been developed based on the Infrared Atmospheric Sounder Interferometer or IASI, which covers the infrared spectral range 645 to 2760 cm-1 with a sampling of 0.25 cm-1. The index has been used to study the 2017 heatwave, which hit Continental Europe from May to October. In particular, we have examined Southern Italy, where Mediterranean forests suffer from climate change. We have computed the index's time series and show that it can be used to indicate the atmospheric background conditions associated with meteorological drought. We have also found a good agreement with soil moisture, which suggests that the persistence of anomalously high water deficit index was an essential driver of the rapid development and evolution of the exceptionally severe 2017 droughts.
ARTICLE | doi:10.20944/preprints202011.0602.v4
Online: 25 May 2021 (10:42:28 CEST)
By taking advantage of a stability criterion established recently, the critical temperature Tc is reckoned with help of the microscopic parameters, characterising the normal and superconducting electrons, namely the independent-electron band structure and a repulsive two-electron force. The emphasis is laid on the sharp Tc dependence upon electron concentration and inter-electron coupling, which might offer a practical route toward higher Tc values and help to understand why high-Tc compounds exhibit such remarkable properties.
ARTICLE | doi:10.20944/preprints202011.0718.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Temperature; Mortality; Heatwave; Epidemiology
Online: 30 November 2020 (11:08:26 CET)
There is increasing evidence that rising temperatures and heatwaves in the United Kingdom are associated with an increase in heat-related mortality. This study aims to retrospectively quantify the impact of heatwaves on mortality during the 2019 summer period using daily death occurrences. Second, it compares excess mortality during the 2019 heatwaves to excess mortality during the 2018 and 2017 heatwave periods. Lastly, it compares the excess mortality in the 2017-2019 heatwaves to the estimated excess deaths for the same period in the Public Health England (PHE) Heatwave mortality monitoring Reports. The cumulative number of excess deaths during the summer 2019 heatwaves were minimal and were substantially lower than during the summer 2018 heatwaves (1,700 deaths) and summer 2017 heatwaves (1,489 deaths). All findings were at variance with the PHE Heatwave mortality monitoring reports which estimated cumulative excess deaths to be 892, 863 and 778 during the summer period of 2019, 2018 and 2017 respectively using provisional death registrations. Issues have been identified in the use of provisional death registrations for mortality monitoring and the reduced reliability of the ONS daily death occurrence database before 2019. These findings may identify more reliable ways to monitor heat mortality during heatwaves in the future.
ARTICLE | doi:10.20944/preprints201811.0455.v1
Online: 19 November 2018 (10:58:10 CET)
In this work, we propose a method to measure planar temperature fields of fluids flow. We used a focusing schlieren technique together with a calibration procedure to fulfill such purpose. The focusing schlieren technique uses an off-axis circular illumination to reduce the depth of focus of the optical system. The calibration procedure is based on the relation of the intensity level of each pixel of a focused schlieren image to the corresponding cutoff grid position measured at the exit focal plane of the schlieren lens. The method is applied to measure planar temperature fields of the hot air issuing from a 10 mm diameter nozzle of a commercial Hot Air Gun Soldering Station Welding. Our tests are carried out at different temperature values and different planes along the radial position of the nozzle of the Hot Air Gun Soldering Station Welding. The temperature values obtained experimentally are in agreed with those obtained with a thermocouple.
ARTICLE | doi:10.20944/preprints201811.0198.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: body temperature; sensors; transduser
Online: 8 November 2018 (10:11:12 CET)
The aim of the study was to evaluate the influence of transduser design and its elements, and their materials on temperature in deeper layers of tissues measurement results. A digital modeling was performed to evaluate the influence of the properties of transduser design elements. Experimental research was carried out. Revealed that the accuracy, similar to that of an invasive method using needle probes, can be achieved by measuring the temperature in deeper muscle layers using the proposed transducer.
ARTICLE | doi:10.20944/preprints201802.0046.v1
Online: 5 February 2018 (16:34:46 CET)
There is a perception among the inhabitants of the Aburrá Valley Region, that this heavily populated region, situated in the Andean mountains of Colombia, has been suffering large temperature elevations in the last years, especially in the last decade. To give perspective about this issue, the authors have gone through the available information about temperature changes in three meteorological stations in the region and have correlated it with a set of variables of urban, climatic and energetic nature, with the intention of developing an approximate model to understand the temperature changes. Changes in the mean temperature, based on the linear correlation of the data were estimated on 0.47oC for the 20 years between 1995 and 2015; the study showed that 60% of change was found to be related to local human activities and 40% was attributed to the impact of global warming. For the local influences some practical mitigation actions are proposed, related to improve the energy management and paying more attention to the temperature changes trough improvements in the number and capability of sampling stations in the urban air and in the river, which serve as clear indicators of the changes and the effect of any mitigation measures.
ARTICLE | doi:10.20944/preprints201712.0072.v1
Online: 12 December 2017 (07:18:48 CET)
There is a perception among the inhabitants of the Aburrá Valley Region, that this heavily populated region, situated in the Andean mountains of Colombia, has been suffering large temperature raises in the last years, especially in the last decade. To give perspective about this issue, the authors have gone through the available information about temperature changes in three meteorological stations in the region and have correlated it with a set of variables of urban, climatic and energetic nature, with the intention of developing an approximate model to understand the temperature changes. Changes in the mean temperature, based on the linear tendencies, were estimated on 0.47ºC for the 20 years between 1995 and 2015; 60% of change was found to be related to local human activities and 40% was attributed to the impact of global warming.
COMMUNICATION | doi:10.20944/preprints202103.0013.v1
Subject: Engineering, Automotive Engineering Keywords: temperature sensor; fiber optic sensor; photonic sensor; atomic layer deposition; microsphere; temperature; ZnO
Online: 1 March 2021 (13:24:14 CET)
This study presents of the microsphere-based fiber-optic sensor with the ZnO ALD coating thickness of 100 nm and 200 nm for temperature measurements. Metrological properties of the sensor were investigated over the temperature range of 100°C to 300°C, with a 10°C step. The interferometric signal is used to control whether the microstructure is intact. Spectrum shift of a reflected signal is used to conclude changes in measured parameter for the sensor with a 100 nm coating, while the reflected signal intensity is an indicator during measurements executed by a sensor with a 200 nm coating. With changing temperature, the peak position or intensity of a reflected signal also changes. The R2 coefficient of the presented sensors indicates a linear fit of over 0.99 to the obtained data. The sensitivity of the sensors, investigated in this study, equals 103.5 nW/°C and 0.019 nm/°C for ZnO thickness of 200 nm and 100 nm, respectively.
ARTICLE | doi:10.20944/preprints202204.0140.v1
Online: 15 April 2022 (08:48:37 CEST)
In this work, thermo-responsive block copolymer brushes modified graphene oxide (GO) nanohybrid was fabricated successfully via the host-guest interaction between β-cyclodextrin functionalized GO and azobenzene-terminated PNIPAM-b-P(St-co-MQ). The block copolymer was synthesized using reversible addition fragmentation chain transfer (RAFT) polymerization based on the monomers of N-isopropylacrylamide (NIPAM), 5-(2-methacryloyl-ethyloxymethyl) -8-quinolinol (MQ), styrene (St) and an azobenzene functional RAFT agent. The 8-hydroxyquinoline units containing in the block polymer can coordinate with CdSe/ZnS quantum dots(QDs) to form a CdSe/ZnS QDs-block copolymer brushes modified graphene oxide fluorescence nanohybrid (QDs/polymer/GO fluorescence nanohybrid) and the resulting fluorescence nanohybrid had a robust temperature responsive property which result from the change in the PNIPAM conformation in the block copolymer on the surface of GO.
REVIEW | doi:10.20944/preprints202202.0047.v1
Subject: Engineering, Civil Engineering Keywords: Bitumen Emulsion; Formulation; Emulsification Temperature.
Online: 3 February 2022 (10:39:10 CET)
The global increase of road infrastructure and its impact on the environment requires serious attention to develop sustainable and environmentally friendly road materials. One group of those materials is produced by using bitumen emulsion. However, there are still scientific and technical obstacles standing against its regular application. The bitumen emulsion formulation process and compositional optimization are subjected to a high number of degrees of freedom. Consequently, obtaining the desired product is mostly based on a series of random and tedious trials because of the enormous number of tests to be carried out. The current review of the physicochemical formulation may indeed be extensively used in helping to reduce the number of unnecessary experimentations as well as discuss the vital aspects in the bitumen emulsion production process. Among these, emulsion stability, viscosity, droplet size (and distribution), bitumen emulsion chemistry, the function of the emulsion components, surfactant type, acids or alkalis, and additives are all discussed and used to define the emulsion's physical properties and reactivity. Besides, current developments in the mechanisms of breaking and setting processes are also summarized. It is discussed how emulsions are graded based on their reactivity, particle charge, and physical features. Two emulsification techniques are outlined namely the colloid mill method and the High Internal Phase Ratio (HIPR) method. Furthermore, some emulsion formulation tools/theories were identified and are explained. In that way, optimized formulations can be used to offer a practical guide for bitumen emulsion manufacturers when trying to formulate a well-defined bitumen emulsion for its use in pavement infrastructure rather than simply to meet standard specifications. This review paper aims to enable the ultimate potential of the bitumen emulsion in the field of cold recycling technology by further following up the research progress of bitumen emulsion manufacturing, therefore, this paper reviews and discusses the literature available up to now on this topic, in road engineering and emulsion chemistry.
ARTICLE | doi:10.20944/preprints202108.0580.v1
Subject: Engineering, Energy & Fuel Technology Keywords: hydrogen; liquefaction; optimization; ambient temperature
Online: 31 August 2021 (16:00:17 CEST)
Hydrogen used as an energy carrier can provide an important route to the decarbonization of energy supplies. However, realizing this opportunity requires a significant increase in both production and transportation capacity. Part of the increase in transportation capacity could be provided by the shipping of liquid hydrogen, but this introduces an energy-intensive liquefaction step into the supply-chain. The energy required for liquefaction can be reduced by developing improved process designs, but since all low-temperature processes are affected by the available heat-sink temperature, local ambient conditions will also affect the energy penalty. This work studies how the energy consumption associated with liquefaction varies with heat-sink temperature through the optimization of design parameters for a typical next-generation hydrogen liquefaction process. The results show that energy consumption increases by around 20%, across the cooling temperature range 5 to 50 °C. Considering just the range 20 to 30 °C there is a 5% increase, illustrating the significant impact ambient temperature can have on energy consumption.
ARTICLE | doi:10.20944/preprints202106.0456.v1
Online: 17 June 2021 (10:17:15 CEST)
Abstract: The effect of some weather parameters (rainfall and temperature) on the production of oil palm in Peninsular Malaysia was investigated. Data were analysed using the Statistical Package for Social Sciences (SPSS 20.0 version), with descriptive statistics, time series analysis, and multiple linear regression (MLR) carried out. SPSS and Microsoft Excel 2010 were used to analyse the results. The MLR model determined the strength of the relationship between oil palm yield (dependent variable) and the changing variables of temperature and rainfall (independent variables). The regression output returned three components; regression coefficients, regression statistics and ANOVA. The findings of the study revealed medium to high rainfall variability at the rate of 0.0008. This implies that rainfall is increasing over time with variations in its amount and intensity. As rainfall increases oil palm FFB production is predicted to increase at a slow rate of 0.0009. The estimation of average annual temperature indicated an increase of 5.6℃ at the rate of 0.0357℃ per year with a temperature maximum of 32.01℃ and minimum of 25.45℃. The result also revealed an increase in oil palm yield at the rate of 0.2581 per year with a mean value of 176247.6. Overall, there is a significant difference in the impact of rainfall and temperature on oil palm yield. This signifies that rainfall has a significant impact on oil palm yield (FFB) compared to temperature.
ARTICLE | doi:10.20944/preprints202003.0366.v3
Subject: Earth Sciences, Environmental Sciences Keywords: COVID-19; coronavirus; temperature; solutions
Online: 21 June 2020 (16:19:26 CEST)
This article investigated whether the atmospheric temperature had any role in the spread and vulnerability to COVID-19 worldwide and how that knowledge can be utilized to contain the fast-spreading disease. It highlighted that temperature was an important factor in transmitting the virus, and a moderately cool environment was the most favourable state for its susceptibility. In fact, the risk from the virus is reduced significantly in high temperature environment. Warm countries and places were likely to be less vulnerable. We identified various degrees of vulnerability based on temperature and specified countries for March and April. The maximum reported case, as well as death, was noted when the temperature was in the range of around 275°K (2°C) to 290°K (17°C). Countries like the USA, UK, Italy and Spain belonged to this category. The vulnerability was moderate when the temperature was less than around 275°K (2°C) and countries in that category were Russia, parts of Canada and few Scandinavian countries. For temperature 300°K (27°C) and above, a significantly lesser degree of vulnerability was noted. Countries from SAARC, South East Asia, the African continent and Australia fell in that category. In fact, when the temperature was more than 305°K (32°C), there was a unusually low number of reported cases and deaths. For warm countries, further analyses on the degree of vulnerability were conducted for the group of countries from SAARC and South East Asia and individual countries were compared. We also showed countries can switch from one vulnerability state to another based on the variability of temperature. We provided maps of temperature to identify countries of different vulnerability states in different months of the year. That influence of temperature on the virus and previous results of clinical trials with similar viruses gave us a useful insight that regulating the level of temperature can provide remarkable results to arrest and stop the outbreak. Based on that knowledge, some urgent solutions are proposed, which are practically without side effects and very cost-effective too.
ARTICLE | doi:10.20944/preprints201909.0285.v1
Subject: Biology, Plant Sciences Keywords: photosynthesis; rubisco; temperature; acclimation; soybean
Online: 25 September 2019 (11:45:22 CEST)
Recent in vivo assays of the responses of Rubisco to temperature in C3 plants have revealed substantial diversity. Three cultivars of soybean (Glycine max L. Merr.), Holt, Fiskeby V, and Spencer, were grown in indoor chambers at 15, 20, and 25 oC. Leaf photosynthesis was measured over the range of 15 to 30 oC, deliberately avoiding higher temperatures which may cause deactivation of Rubisco, in order to test for differences in temperature responses of photosynthesis, and to investigate in vivo Rubisco kinetic characteristics responsible for any differences observed. The three cultivars differed in the optimum temperature for photosynthesis (from 15 to 30 oC) at 400 µmol mol-1 external CO2 concentration when grown at 15 oC, and in the shapes of the response curves when grown at 25 oC. The apparent activation energy of the maximum carboxylation rate of Rubisco differed substantially between cultivars at all growth temperatures, as well as changing with growth temperature in two of the cultivars. The activation energy ranged from 58 to 84 kJ mol-1, compared with the value of 64 kJ mol-1 used in many photosynthesis models. Much less variation in temperature responses occurred in photosynthesis measured at nearly saturating CO2 levels, suggesting more diversity in Rubisco than in electron transport thermal properties among these soybean cultivars.
ARTICLE | doi:10.20944/preprints201901.0136.v2
Online: 18 January 2019 (12:42:19 CET)
With the increasing pace of global warming, it is important to understand the role of meteorological factors in influenza virus (IV) epidemics. In this study, we investigated the impact of temperature, UV index, humidity, wind speed, atmospheric pressure, and precipitation on IV activity in Norway, Sweden, Finland, Estonia, Latvia and Lithuania during 2010-2018. Both correlation and machine learning analyses revealed that low temperature and low UV indexes were the most predictive meteorological factors for IV epidemics in the Northern European countries. Our in vitro experiments confirmed that low temperature and UV radiation preserved IV infectivity. Associations between these meteorological factors and IV activity could improve surveillance and promote development of accurate predictive models for future influenza outbreaks in Northern Europe.
ARTICLE | doi:10.20944/preprints201808.0063.v2
Subject: Materials Science, Metallurgy Keywords: ferrite formation; mushy zone temperature, liquidus and solidus temperature, ingot forming, 0Cr17Ni4Cu4Nb stainless steel
Online: 24 August 2018 (05:10:49 CEST)
Ferrite body is the origin of crack and corrosion initiation of steels. Distribution and density of ferrite in seven steel ingots were examined by light optical microscopy and computational modeling in the study to explore the correlation of ferrite formation to chemical composition and mushy zone temperature in ingot forming. The central segregation phenomenon in ferrite distribution was observed in all the examined steel specimens except 0Cr17Ni4Cu4Nb stainless steel. No significant difference was found in distribution and density of ferrite amongst zones of the surface, ½ radius and core in neither risers nor tails of 0Cr17Ni4Cu4Nb ingots. Additionally, fewer ferrite was found in 0Cr17Ni4Cu4Nb compared to other examined steels. The difference of ferrite formation in 0Cr17Ni4Cu4Nb elicited a debate on the traditional models explicating ferrite formation. Considering the compelling advantages in mechanical strength, plasticity and corrosion resistance, further investigation on the unusual ferrite formation in 0Cr17Ni4Cu4Nb would help understand the mechanism to improve steel quality. In summary, we observed that ferrite formation in steel was correlated with mushy zone temperature. The advantages of 0Crl7Ni4Cu4Nb in corrosion resistance and mechanical stability could be resulted from that fewer ferrites formed and distributed in a scattered manner in microstructure of the steel.
ARTICLE | doi:10.20944/preprints201807.0274.v1
Subject: Life Sciences, Other Keywords: asymmetry; mean skin temperature; non-uniform; outdoor environment; physiological response; skin temperature; solar radiation
Online: 16 July 2018 (10:46:36 CEST)
Depending on human body conditions and environmental conditions, it is sometimes difficult to conduct subject experiments. In such cases, it is effective to use a thermal manikin. There are few studies that investigate the effect of the non-uniform and asymmetric outdoor thermal environment on the mean skin temperature. The purpose of this study is to clarify the influence of the non-uniform and asymmetric thermal radiation of short-wavelength solar radiation in an outdoor environment on the calculation of the mean skin temperature. The skin temperature of the front of the coronal surface, which was facing the sun and where the body received direct short-wavelength solar radiation, and the skin temperature of the rear of the coronal surface, which was in the shadow and did not receive direct short-wavelength solar radiation were respectively measured. The feet, upper arm, forearm, hand and lower leg, which are susceptible to short-wavelength solar radiation in a standing posture, had a noticeable difference in skin temperature between sites in the sun and in shade. The mean skin temperature of sites facing the sun was significantly higher than the mean skin temperature of those in the shade.
Subject: Physical Sciences, Acoustics Keywords: cosmological constant; finite temperature; quantum gravity
Online: 8 January 2021 (14:26:20 CET)
The cosmological constant problem is examined by taking an Einstein--scalar with a Higgs-type potential and scrutinizing the infrared structure induced by finite temperature effects. A variant optimal perturbation theory is implemented in the recently proposed quantum-gravitational framework. The optimized renormalized mass, i.e., the renormalized mass determined by the variant optimal perturbation theory, of the scalar field turns out to be on the order of the temperature. This shifts the cosmological constant problem to compatibility of the consequent perturbative analysis. The compatibility is guaranteed essentially by renormalization group invariance of physical quantities. We point out the resummation behind the invariance.
ARTICLE | doi:10.20944/preprints202007.0394.v1
Subject: Materials Science, Polymers & Plastics Keywords: thermal properties; temperature diffusivity; nano cellulose
Online: 17 July 2020 (15:36:15 CEST)
The thermal properties of novel nanomaterials play a significant role in determining the performance of the material in technological applications. Herein, direct measurement of the temperature diffusivity of cellulose nanocomposite films was carried out by the micro-contact method. Polymer films containing up to 2%wt. of nanocellulose were synthesised by a simple chemical process. Films of a high optical transmittance T ≈ 80 % (for a 200- μ m-thick film), which were up to 44% crystalline, were characterised. Two different modalities of temperature diffusivity based on: 1) a resistance change and 2) micro-thermocouple detected modulation of a heat wave, were used for the polymer films with cross-sections of ∼ 100 μ m thickness. Twice different in-plane α ‖ and out-of-plane α ⊥ temperature diffusivities were directly determined with high fidelity: α ‖ = 2 . 12 × 10 − 7 m 2 /s and α ⊥ = 1 . 13 × 10 − 7 m 2 /s. An amorphous polyethylene terephthalate (PET) fiber was measured for comparison α ‖ = 1 . 15 × 10 − 7 m 2 /s. This work provides an example of a direct contact measurement of thermal properties of nanocellulose composite films. The thermal diffusivity, which is usually high in strongly interconnected networks and crystals, was investigated for the first time in this composite.
ARTICLE | doi:10.20944/preprints202002.0095.v1
Subject: Earth Sciences, Other Keywords: permafrost; temperature; nonlinear fitting; prediction model
Online: 7 February 2020 (11:31:37 CET)
The pile foundation in the permafrost region is in a negative temperature environment, so the concrete is affected by the negative temperature of the surrounding soil.It not only affects the formation of concrete strength, but also leads to engineering quality accidents in serious cases.Based on the actual measurement of temperature at different strata depths and the comprehensive consideration of surface temperature, terrestrial heat flux and other parameters, the law curve of temperature change along depth in Greater Khingan is established.The calculated results of the curve are consistent with the measured results of ground temperature.The results show that the variation trend of ground temperature along the strata depth at different monitoring sites is basically the same. From June to November, the ground temperature at different depths tends to be constant.From December to May, the ground temperature at any depth within the depth range of 0 to 5.5m follows the law of the cosine function.Below 5.5m, the earth temperature no longer varies with depth.The research results can be used as reference for pile foundation construction under negative temperature environment.
ARTICLE | doi:10.20944/preprints201910.0109.v1
Subject: Engineering, Energy & Fuel Technology Keywords: CO2; liquefaction; ccs; optimization; ambient temperature
Online: 10 October 2019 (04:36:07 CEST)
In CCS projects, the transportation of CO2 by ship can be an attractive alternative to transportation using a pipeline, particularly when the distance between source and disposal location is large. However, the energy consumption of the liquefaction process can be significant, making the selection of an energy-efficient design an important factor in the minimization of operating costs. Since the liquefaction process operates at low temperature, its energy consumption will vary with ambient temperature, which could be a factor that influences the trade-off point between pipelines and shipping in different geographic locations. A consistent set of data showing the relationship between energy consumption and cooling temperature is therefore potentially useful to CCS system modelling. This study compares the performance of a wide range of CO2 liquefaction schemes. It applies a methodical approach to the optimization of process operating parameters and studies performance across a range of operating temperatures. A set of data for the minimum energy consumption cases is presented. The main findings are that open-cycle CO2 processes often offer minimum energy consumption; NH3 based schemes often offer better performance at higher ambient temperatures; and that for the cooling temperature range 15 to 50 °C, the energy consumption for the best performing liquefaction process rises by around 40%.
ARTICLE | doi:10.20944/preprints201906.0008.v1
Subject: Earth Sciences, Geoinformatics Keywords: Air temperature; MODIS; machine learning; interpolation
Online: 3 June 2019 (08:48:32 CEST)
Several methods have been tried to estimate air temperature using satellite imagery. In this paper, the results of two machine learning algorithms, Support Vector Machine and Random Forest, are compared with Multivariate Linear Regression, TVX and Ordinary kriging. Several geographic, remote sensing and time variables are used as predictors. The validation is carried out using four different statistics on a daily basis allowing the use of ANOVA to compare the results. The main conclusion is that Random Forest with residual kriging produces the best results (R$^2$=0.612 $\pm$ 0.019, NSE=0.578 $\pm$ 0.025, RMSE=1.068 $\pm$ 0.027, PBIAS=-0.172 $\pm$ 0.046), whereas TVX produces the least accurate results. The environmental conditions in the study area are not really suited to TVX, moreover this method only takes into account satellite data. On the other hand, regression methods (Support Vector Machine, Random Forest and Multivariate Linear Regression) use several parameters that are easily calculated from a Digital Elevation Model, adding very little difficulty to the use of satellite data alone. The most important variables in the Random Forest Model were satellite temperature, potential irradiation and cdayt, a cosine transformation of the julian day.
ARTICLE | doi:10.20944/preprints201809.0471.v1
Subject: Chemistry, Chemical Engineering Keywords: algaecides; dirt; humidity; resilience; temperature; time
Online: 25 September 2018 (03:45:11 CEST)
Algaecides are chemicals that cause serious health problems. Conventional paints contain algaecides to improve the algae resistance on the paint film. Present research has suggested an environmental friendly paint formulation that focuses on developing algae resistance without having algaecides. In this research, Algae growth on newly developed paint is modeled by incorporating dirt resistance of paint and natural phenomena including humidity, temperature and time respectively. The fitted Model revealed explained variation of 59.65% in the average algae growth, of which, Dirt Resistance, Humidity and temperature and some of their interactions play significant role in this variation. Model suggests that the proposed newly developed paint without algaecides is more resilient to algae growth and significantly decreased the average algae growth rate by 0.53% as compared to conventional paints. Keeping the effect of all other factors constant, if dirt resistance of paint (Dc value) increases by one percent, average algae growth decreases by 12.98%; when temperature increases by 1oC, average algae growth decreases by 22.4%; a positive unit change in the joint linear effect dirt resistance, temperature and humidity caused a decrease in average algae growth by 0.0031%. It was also observed that the individual effect of humidity variable was inversely related with average algae growth. However the combination of humidity and temperature, humidity and dirt resistance, humidity and time, and the quadratic effect of humidity were found to increase the average algae growth rate. The cubic effect of temperature variable by one degree centigrade resulted in decrease of average algae growth by 0.000907%.
ARTICLE | doi:10.20944/preprints201809.0180.v1
Subject: Earth Sciences, Environmental Sciences Keywords: local climate change; nitrification; monochloramine; temperature
Online: 11 September 2018 (04:18:59 CEST)
In this study, air temperatures were collected between 1985 and 2016 and compared to water temperatures in four locations in the distribution system of Pasadena Water & Power (PWP) that received imported surface water between 2001 and 2016 and from the purveyor of imported water. The concentration of chloramine residual and nitrite concentrations were collected between 2001 and 2016 these five locations. The results indicate that the median nighttime temperature of the period 2009 - 2016 was 1.6 oC warmer than the period of 1985 - 2000 and 0.5 oC warmer than the period 2001 - 2008. The median water temperature in the four distribution system samples increased by 0.8 oC to 1.4 oC depending on the location over the study period (p<0.001). The median chloramine concentration fell significantly (p<0.001) at three distribution system locations and the nitrite concentrations increased significantly at all four distribution system locations.
ARTICLE | doi:10.20944/preprints201809.0167.v1
Subject: Biology, Other Keywords: Temperature, Culture, Cell, Chick, Embryo, Rotation
Online: 10 September 2018 (12:02:12 CEST)
Recently, some authors have developed a shell-less culture system for chick embryos by using a plastic lm as culture vessels. We will show that velocity of rotation of vessels in incubator and temperature have direct relations with growth of chick embryos. We also obtain a mathematical relation between velocity, temperature and rate of growth of chick embryo.
ARTICLE | doi:10.20944/preprints201807.0450.v1
Subject: Physical Sciences, Applied Physics Keywords: temperature-detection; thread; PEDOT:PSS; wearable devices
Online: 24 July 2018 (08:28:17 CEST)
In this research, we developed a wearable temperature-sensing element by dip dyeing threads in poly (3, 4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) (p-type conducting polymer) solution. The PEDOT:PSS was used to dye the textile and it exhibited negative temperature coefficient characteristics in which the resistance decreases as the temperature increases. The fabricated temperature-detection thread achieved a sensitivity of 167.1 W/°C with 99.8% linearity in the temperature range of -50 to 80 °C. We anticipate that temperature sensors that apply our technology will be made as stitch- or textile-type for wearable devices, and they will be widely adopted for different applications such as in fitness, leisure, healthcare, medical treatment, infotainment, industry, and military applications, among others.
ARTICLE | doi:10.20944/preprints202209.0382.v1
Subject: Materials Science, General Materials Science Keywords: ZnO; sol gel; temperature; band gap; simulation
Online: 26 September 2022 (07:42:25 CEST)
ZnO was synthesized by Sol gel method using zinc nitrate as precursor at different calcination temperatures. Nucleation of ZnO crystallites and their growth with rise in temperature was observed. Exciton bands and lattice imperfections affected the absorption spectra. The decrease in band gap with temperature was due to the formation of defect energy levels. Phonon assisted non-radiative transitions caused broadening of the peaks. The possibility of tuning the band gap of ZnO by changing the temperature was explored. Simulation studies showed transition to single phase with rise in temperature.
ARTICLE | doi:10.20944/preprints202203.0044.v1
Subject: Physical Sciences, Radiation & Radiography Keywords: energetic material; plasma; detonation; electromagnetism; high temperature
Online: 2 March 2022 (10:39:48 CET)
In the process of deflagration of energetic materials, strong electromagnetic radiation is to be generated, which causes the surrounding electronic equipment to fail to work normally. To solve this problem, it is necessary to clarify the mechanism of electromagnetic radiation generated by energetic materials. The mechanism of plasma changed by the deflagration of energetic materials is an important topic in the aerospace and geophysics fields. The academic community holds two main viewpoints on the mechanism of electromagnetic radiation generated by energetic materials: one is that the solid material is squeezed and deformed during the deflagration of energetic materials, and the charges of different polarities rub in space to form effective electric dipoles, which eventually generate electromagnetic radiation. Another view is that the deflagration of energetic materials causes the temperature of the medium to rise sharply, and bremsstrahlung is formed during the compression and diffusion of the high-temperature wave front, resulting in the generation of electromagnetic radiation. This paper, based on theoretical analysis and experimental data, holds the view that electromagnetic radiation is generated by the high-temperature thermal effect. It studies the relationship between temperature and electromagnetic radiation and obtains quantitative analysis conclusions.
ARTICLE | doi:10.20944/preprints202109.0089.v1
Online: 6 September 2021 (12:07:02 CEST)
Pepper plants experience complex environmental factors including abiotic and biotic stresses in field and the importance of climate changes including low and high temperatures has been emerged. Low temperature stress in the growth and development is one of the most critical issues, which directly impact on the crop yield and productivity of pepper plants. It is essential to select and breed low temperature-(LT) tolerant pepper (Capsicum annuum L.) cultivars. The research was performed to assess the agronomical traits of 39 pepper accessions belonging to chili and bell fruit types which cultivated two different night temperature set-points at 15°C for suboptimal temperature (CT) and at 10°C for low temperature (LT), respectively. Plant heights (PH) of most pepper accessions in LT were significantly decreased compared to those in CT. The stem diameter (SD) and the length of main axis (LMA) were various depending on the genotypes under LT. Moreover, the number of flowers (NFL), the total number of fruits (NFR), fruit yield (FY), fruit fresh weight (FFW), fruit length (FL), fruit diameter (FD), and the number of seeds in a fruit (NSF) were notably declined in LT compared to CT. The evaluated agronomical traits between LT and CT were further applied for the correlation analysis, the principal component analysis (PCA), and the hierarchical cluster analysis. Notably, FY trait was correlated with other reproductive traits including NFR, FFW, FD, and FL on positive directions and LT treated-39 pepper accessions were clustered into seven groups by the clustering analysis. The selected accessions were primarily involved with the positive trends with the reproductive index including NFR, FL, FD, and FW traits and would be used for pepper breeding programs on developing LT-tolerant cultivars.
ARTICLE | doi:10.20944/preprints202107.0168.v1
Subject: Biology, Anatomy & Morphology Keywords: lizard; autotomy; tail; locomotion; performance; temperature; predation
Online: 7 July 2021 (08:00:27 CEST)
Caudal autotomy is a dramatic adaptation used by many lizard species to evade predators. Most studies to date indicate that caudal autotomy impairs lizard locomotor performance. Surprisingly, some species bearing the longest tails show negligible impacts of caudal autotomy on sprint speed. Part of this variation has been attributed to lineage effects. For the first time, we model the effects of caudal autotomy on the locomotor performance of a gymnophthalmid lizard, Micrablepharus atticolus, characterized by a long and bright blue tail. To improve model accuracy, we incorporated the effects of several covariates. We found that body temperature, pregnancy, mass, collection site, and the length of the regenerated portion of the tail were the most important predictors of locomotor performance in Micrablepharus atticolus. However, sprint speed was unaffected by tail loss. Apparently, the long tail of M. atticolus is more useful when using undulation amidst the leaf litter and not when using quadrupedal locomotion on a flat surface. Our findings highlight the intricate relationships among physiological, morphological, and behavioral traits. We suggest that future studies about the impacts of caudal autotomy among long-tailed lizards should consider the role of different microhabitats/substrates on locomotor performance, using laboratory conditions that closely mimic their natural environments.
ARTICLE | doi:10.20944/preprints202106.0720.v1
Subject: Arts & Humanities, Anthropology & Ethnography Keywords: Biochar; Cadmium; Pyrolysis temperature; Adsorption kinetics; Desorption
Online: 30 June 2021 (09:10:01 CEST)
Biochar has high potential usage in retaining various contaminants, wastewater treatment, and water purification. In this study, three rice husk derived biochars with pyrolysis temperature 300, 400 and 500 ºC, respectively, and pristine rice rusk were used to remove cadmium from aqueous solution. The results showed that about 70% or more of Cd2+ adsorption occurred in the first 960 mins of adsorption kinetics. The Cd2+ adsorption capacity under equilibrium increased with increasing pyrolysis temperature, probably attributed to the increased specific surface area (SSA) under higher pyrolysis temperature noting that significant linear correlation occurred between Cd2+ adsorption capacity and SSA. The Cd2+ adsorption could be best fitted by pseudo-second order model relative to Elovich model and pseudo-first order model. The Cd2+ adsorption rates were higher in ﬁlm diffusion stage, indicating that ﬁlm diffusion stage was signiﬁcant and fast in the early stage of Cd2+ adsorption. In contrast, Cd2+ adsorption by intra-particle diffusion accounted for 47.0%, 47.9% and 43.9% on average of the total Cd2+ adsorption, respectively, indicating that intra-particle diffusion of Cd2+ played a more predominant role in limiting Cd2+ adsorption rate. When reaching Cd2+ desorption equilibrium, removal ratio (RR) values were averaged 0.96, 0.91, and 0.90 under three initial concentrations. More than 90 percentage on average of Cd2+ was removed from aqueous solution by biochars and rice rusk as well, thus biochars can be used to efficiently remove contaminants from aqueous environment. Cation exchange, electrostatic attraction, and the complexation with surface functional groups could be the main dominant mechanisms for Cd2+ adsorption-desorption on biochars.
ARTICLE | doi:10.20944/preprints202103.0781.v1
Subject: Earth Sciences, Atmospheric Science Keywords: NAO; EA; temperature-precipitation covariability; Iberian Peninsula
Online: 31 March 2021 (15:55:23 CEST)
The combined influence of the North Atlantic Oscillation (NAO) and the East Atlantic (EA) patterns on the covariability of temperatures and precipitation in 35 stations of the Iberian Peninsula during the period 1950-2019 is analysed in this work. Four EA-NAO composites were defined from teleconnection patterns positive and negative phases: EA+NAO+, EA+NAO-, EA-NAO+, and EA-NAO-. Daily data of maximum and minimum temperature were used to obtain seasonal means (TX, and TN, respectively), and the covariability of these variables with accumulated seasonal rainfall (R) was studied comparing results obtained for different NAO and EA composites. Main results indicate slight differences in the spatial coverage of correlation coefficients between R and temperature variables, except in spring when the generalized negative relationship between R and TX under EA+NAO+ and EA-NAO- disappears under EA-NAO+ and EA+NAO- composites. This result may be useful to interpret and discuss historical reconstructions of Iberian climate.
ARTICLE | doi:10.20944/preprints202101.0188.v1
Online: 11 January 2021 (12:30:55 CET)
The present study analyzed seasonal (i.e., Dec-Jan [DJF] and June – August [JJA]) temperature change for the near (2025-2054) and far future (2070-2099) under SSP245, SSP370, and SSP585 scenarios over Pakistan. The anomalies, Mann-Kendall trend tests, Sequential Mann-Kendall trend test (SQMK), and probability density frequency (PDF) analysis were used to investigate future mean temperature variations. The DJF season projected higher increase in temperature in the northern (3.8 oC, 5.1 oC and 6.5 oC), followed by central regions (3.8 oC, 4.9 oC and 6.4 oC) under SSP245, SSP370 and SSP585 scenarios, respectively. The central region is likely to record significant increase in JJA (3.0 oC, 4.4 oC and 5.4 oC) mean temperature in far future under the given SSP scenarios. Compared to historical (PDF), the far future DJF temperature changes revealed significant higher warming over northern, central and then over southern regions under most of SSP scenarios. The southern regions are projected to possible rise in far future JJA temperatures by 2.7 oC, 3.3 oC and 4.3 oC, under SSP245, SSP370 and SSP585, respectively. The PDFs for JJA further verify the highest positive abrupt shift in temperature across the central region and then southern region. The future diverse seasonal temperature changes supports further examination of the associated mechanisms and factors responsible for temperature changes to address climate change.
Subject: Physical Sciences, Acoustics Keywords: proto-quark stars; maximum temperature; mass reduction
Online: 9 December 2020 (09:47:40 CET)
Abstract: The paper defines the characteristics of two proto-quark stars (M_b=1.22M_? and M_b=1.62M_(?"\ " )) that were formed after the explosion of the supernova. It is assumed that the changes in the energy and lepton charge of the central regions of the pre-supernova star can be neglected during the implosion. The equation of state for hot quark matter is determined based on the MIT bag theory taking into account the presence of neutrinos. The possible maximum values of the central temperatures of these stars are determined. The energy of neutrinos in the studied proto-quark stars is of the order of 250-300 MeV. The decrease in the mass of these stars during cooling is about 0.16 for M_b=1.22M_? and 0.25 for M_b=1.62M_(?"\ " ).
ARTICLE | doi:10.20944/preprints202012.0159.v1
Subject: Earth Sciences, Atmospheric Science Keywords: ash; brightness temperature; Cumulonimbus; eruption; TIR,; volcano
Online: 7 December 2020 (13:45:54 CET)
Mount Semeru is one of the most active volcanoes in the Java Island. This article presents the results of observations and detections of volcanic ash cloud after Mt Semeru eruptions on 1 December 2020 at 01:23 AM. Volcanic ash cloud detection was conducted by analyzing thermal infrared (TIR) satellite images acquired by the NOAA-20 and SNPP with MODIS and VIIRS instruments. The TIR instruments have detected the presence of volcanic ash cloud. The results show increasing ash cloud brightness temperature (BT) from 240 to 270 Kelvin (K) several hours after eruptions. Increasing BT indicated the development of volcanic Cumulonimbus (Cb) at lower altitude. Northeast movements of 270 K BT clouds were observed at 06:12 AM. Presences of volcanic Cb and SO2 were confirmed using IR bands of 12.0-10.8 µm, 11.0-8.5µm and 11.0 µm. This Cb cloud was observed moving northeast directions. The data acquired from the TIR imagery resulted from this study is thought be used in future to support and complement ground-based observations and detections of active volcanoes mainly in Java Island.
ARTICLE | doi:10.20944/preprints202010.0206.v1
Subject: Biology, Anatomy & Morphology Keywords: bioclimatic zones; climate change; precipitation; temperature; trend
Online: 9 October 2020 (14:03:16 CEST)
Abstract Depending upon altitudinal gradient in the Himalayas, the rate of climate change varies from lowland to upland. The Chitwan Annapurna Landscape (CHAL) is the central part of the Himalayas and covers all bioclimatic zones. Analysis of time series data (1970-2019) of temperature and precipitation was carried out in seven bioclimatic zones extending from lowland Terai to higher Himalayas. The non-parametric Mann-Kendall test was applied to determine the trend, which was quantified by Sen’s slope. Annual and decade interval average temperature, precipitation trends, and lapse rate were analyzed in each bioclimatic zone. Out of seven bioclimatic zones, four zones showed a decreasing precipitation trend (lower tropical, upper tropical, upper subtropical, and alpine bioclimatic zones)at the rate of 1.8, 1.98, 2.06, and 1.80 mm/year, and in lower sub-tropical, temperate, and lower subalpine bioclimatic zones, increasing at the rate of 0.45, 1.81 and 1.28mm/year, respectively. Precipitation did not show any particular trend at decade intervals. The average annual temperature at different bioclimatic zones clearly indicates that temperature at higher elevations is significantly increasing more than at lower elevations. In lower tropical bioclimatic zone (LTBZ), upper tropical bioclimatic zone(UTBZ), lower subtropical bioclimatic zone (LSBZ), upper subtropical bioclimatic zone(USBZ), and temperate bioclimatic zone(TBZ), the average temperature increased by 0.022, 0.030, 0.036, 0.042 and 0.051oC/year, respectively. The decade level temperature scenario revealed that the hottest decade was from 1999-2009. The average temperature was found as 24.1, 21.8, 19.7, 17.5, and 13.3oC in LTBZ, UTBZ, LSBZ, USBZ, and TBZ, respectively, and the average annual precipitation in LTBZ, UTBZ, LSBZ, USBZ, TBZ, LBZ, and ABZ was 2002.1, 2613.1, 2223.9, 3146.9, 1447.2, 952.1, and 361.7mm/year, respectively, in CHAL. With the impact of climate change site and region-specific, this information highlights the need to mitigate climate change in different bioclimatic zones.
Subject: Earth Sciences, Atmospheric Science Keywords: temperature precursors; carbon dioxide; HadCRUT4; Mauna Loa
Online: 26 June 2020 (12:30:25 CEST)
The non-secular anomalies in carbon dioxide measurements at Mauna Loa are compared to the non-secular anomalies in the HadCRUT4 median global temperature from 1991 to 2020. A strong and significant Pearson's product-moment correlation is found between carbon dioxide anomalies and global temperature anomaly, indicating that the correlation is an actual characteristic of the atmosphere. But more important from a numerical weather prediction perspective, this result indicates that carbon dioxide anomalies can have no skills as temperature precursors on short time scales.
ARTICLE | doi:10.20944/preprints202002.0459.v1
Subject: Engineering, Energy & Fuel Technology Keywords: low concentration; gas; reactor; high-temperature oxidation
Online: 29 February 2020 (09:20:28 CET)
To achieve efficient utilization of low-concentration mine gas, reduce resource waste, and alleviate environmental pollution, high-temperature oxidation of low-concentration gas at a concentration range of 1.00% to 1.50% that is directly discharged into the atmosphere during coal mine production was oxidized to recover heat for reuse. The gas oxidation equipment was improved for the heating process, and the safety of low-concentration gas oxidation under high-temperature environment was evaluated. Experimental results showed that the reactor could provide a 1000 ℃ high-temperature oxidation environment for gas oxidation after installing high-temperature resistant ceramics. The pressure variation curves of the reactor with air and different concentrations of gas were similar. Due to the thermal expansion, the air pressure slightly increased and then returned to normal pressure. In contrast, the low-concentration gas exhibited a stable pressure response in the high-temperature environment of 1000 ℃. The outlet pressure was significantly greater than the inlet pressure, and the pressure difference between the inlet and outlet exhibited a trend to increase with the gas concentration. The explosion limit varied with the temperature and the blend with oxidation products. The ratio of measured gas pressure to air pressure after oxidation was below the explosion criterion, indicating that the measured concentration gas is still safe after the shift of explosion limit, which provides a safe concentration range for efficient use of low-concentration gas in the future.
ARTICLE | doi:10.20944/preprints202002.0058.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Historical climatology; Spain; Dalton Minimum; temperature; rainfall
Online: 5 February 2020 (10:41:40 CET)
New data on the climate in southern Spain from 1792 to 1808 are analyzed in this work. The data source is the newspaper Correo Mercantil de España y sus Indias, where summaries of the weather conditions in Spain were published at weekly resolution. The study is focused on southern provinces, providing 2788 new records, some of them corresponding to areas without data previously recorded. The analysis indicates the predominance of cold-dry winters, cold-wet springs, warm-dry summers, and variable conditions in autumn, from west (cold-wet) to east (warm-dry). Some examples of these situations are presented.
ARTICLE | doi:10.20944/preprints202001.0198.v1
Subject: Engineering, Other Keywords: transplanter; hydraulic oil; temperature; viscosity; proportional valve
Online: 18 January 2020 (09:24:36 CET)
This study was conducted to develop a PID control algorithm considering viscosity for the planting depth control system of a rice transplanter using various hydraulic oils at different temperatures and to evaluate the performance of the control algorithm, and compare the performance of the PID control algorithm without considering viscosity and considering viscosity. In this study, the simulation model of the planting depth control system and a PID control algorithm were developed based on the power flow of the rice transplanter (ERP60DS). The primary PID coefficients were determined using the Ziegler–Nichols (Z–N) second method. Routh’s stability criteria were applied to optimize the coefficients. The pole and double zero points of the PID controller were also applied to minimize the sustained oscillations of the responses. The performance of the PID control algorithm was evaluated for three ISO (The International Organization for Standardization) standard viscosity grade (VG) hydraulic oils (VG 32, 46, and 68). The results show that the control algorithm considering viscosity is able to control the pressure of the proportional valve, which is associated with the actuator displacement for various types of hydraulic oils. It was noticed that the maximum pressure was 15.405 bars at 0, 20, 40, 60, 80, and 100 ℃ for all of the hydraulic oils. The settling time and steady-state errors were 0.45 s at 100 ℃ for VG 32, and 0% for all of the conditions. The maximum overshoots were found to be 17.50% at 100 ℃ for VG 32. On the other hand, the PID control algorithm without considering viscosity could not control the planting depth, because the response was slow and did not satisfy the boundary conditions. The PID control algorithm considering viscosity could sufficiently compensate for the nonlinearity of the hydraulic system and was able to perform for any of temperature-dependent viscosity of the hydraulic oils. In addition, the rice transplanter requires a faster response for accurately controlling and maintaining the planting depth. Planting depth is highly associated with actuator displacement. Finally, this control algorithm considering viscosity could be helpful in minimizing the tilting of the seedlings planted using the rice transplanter. Ultimately, it would improve the transplanter performance.
ARTICLE | doi:10.20944/preprints201912.0032.v1
Subject: Life Sciences, Biophysics Keywords: temperature dependence, flux reversal, entropy production density
Online: 4 December 2019 (02:44:02 CET)
Temperature influences the life of many organisms in various ways. A great number of them live under conditions, where their ability to adapt to changes in temperature can be vital and largely determine their fitness. Understanding the mechanisms and principles underlying this ability to adapt can be of great advantage, for example, to improve growth conditions for crops and increase their yield. In times of imminent, increasing climate change, this becomes even more important, in order to find strategies and help crops cope with these fundamental changes. There is intense research in the field of acclimation, that comprises fluctuations of various environmental conditions, but most acclimation research focuses on regulatory effects and the observation of gene expression changes within the examined organism. As thermodynamic effects are a direct consequence of temperature changes, these should necessarily be considered in this field of research, but are often neglected. Also, compensated effects might be missed, even though they are equally important for the organism, since they do not cause observable changes, but rather counteract them. In this work, using a systems biology approach, we demonstrate that even simple network motifs can exhibit temperature dependent functional features, resulting from the interplay of network structure and the distribution of activation energies over the involved reactions. The demonstrated functional features are (i) the reversal of fluxes within a linear pathway, (ii) a thermo-selective branched pathway with different flux modes and (iii) the increased flux towards carbohydrates in a minimal calvin cycle that was designed to demonstrate temperature compensation within reaction networks. By this, we expand the scope of thermodynamic modelling of biochemical processes by addressing further possibilities and effects, following established mathematical descriptions of biophysical properties.
ARTICLE | doi:10.20944/preprints201909.0268.v1
Subject: Earth Sciences, Atmospheric Science Keywords: land surface temperature; remote rensing; reanalysis; ECMWF
Online: 24 September 2019 (05:18:26 CEST)
Land surface temperature (LST) is a key variable in surface-atmosphere energy and water exchanges. The main goals of this study are to (i) evaluate the LST of the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim and ERA5 reanalyses over Iberian Peninsula using the Satellite Application Facility on Land Surface Analysis (LSA-SAF) product and to (ii) understand the main drivers of the LST errors in the reanalysis. Simulations with the ECMWF land-surface model in offline mode (uncoupled) were carried out over the Iberian Peninsula and compared with the reanalysis data. Several sensitivity simulations were performed in a confined domain centered in Southern Portugal to investigate potential sources of the LST errors. The Copernicus Global Land Service (CGLS) fraction of green vegetation cover (FCover) and the European Space Agency’s Climate Change Initiative (ESA-CCI) Land Cover dataset were explored. We found a general underestimation of daytime LST and slightly overestimation at night-time. The results indicate that there is still room for improvement in the simulation of LST in ECMWF products. Still, ERA5 presents an overall higher quality product in relation to ERA-Interim. Our analysis suggested a relation between the large daytime cold bias and vegetation cover differences between (ERA5 and CGLS FCocver) with a correlation of -0.45. The replacement of the low and high vegetation cover by those of ESA-CCI provided an overall reduction of the large Tmax biases during summer. The increased vertical resolution of the soil at the surface, has a positive impact, but much smaller when compared with the vegetation changes. The sensitivity of the vegetation density parameter, that currently depends on the vegetation type, provided further proof for a needed revision of the vegetation in the model, as there is a reasonable correlation between this parameter and the Tmax mean errors when using the ESA-CCI vegetation cover (while the same correlation cannot be reproduced with the original model vegetation). Our results support the hypothesis that vegetation cover is one of the main drivers of the LST summertime cold bias in ERA5 over Iberian Peninsula.
ARTICLE | doi:10.20944/preprints201906.0150.v1
Subject: Engineering, General Engineering Keywords: laser diode; wavelength; stimulated emission; temperature effect
Online: 16 June 2019 (16:53:46 CEST)
The present work is a theoretical and experimental study of temperature effect on wavelength and threshold current. Since Semiconductor lasers are the type of lasers which uses semiconductor material as a gain medium to achieve stimulated emission of radiation. In this module, the type of semiconductor lasers use is VCSEL and laser diode. Temperature change cause Semiconductor lasers to shift its threshold current, this variation also causes a shift in output wavelength. The experimental results highly agreement with the theoretical calculations.
ARTICLE | doi:10.20944/preprints201904.0238.v1
Subject: Biology, Animal Sciences & Zoology Keywords: residual feed consumption; quail; high environmental temperature
Online: 22 April 2019 (11:22:21 CEST)
Three hundred ten 12-wek-old laying quails (155 each) were randomly selected from the initial population and kept in individual battery cages. The measurements of growth and egg production were determined to derive RFI. The relationship between RFI and egg quality, blood parameters and carcass characteristics was also determined. The results indicated that the gray quails had significantly higher egg mass and lower broken eggs compared to the white quails. A significant increase for eggshell strength and shell % was found in eggs produced from gray quails compared to white counterparts, although the shell thickness was the same. The results of multiple regression analysis clearly identified a significant effect of metabolic body weight and egg mass in computing expected feed intake rather than body weight gain in both varieties of Japanese quails. Strongly positive correlation between RFI and feed intake in both gray and white quail varieties was found. The same trend was also observed for feed conversion ratio (FCR). Therefore, including RFI in selection criteria of Japanese quail to improve FCR under high environmental temperature is highly recommended.
ARTICLE | doi:10.20944/preprints201901.0076.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: agitator; dirt; humidity; nano mill; temperature; time
Online: 8 January 2019 (15:34:45 CET)
A highly dirt resistant paint for building facades without chemicals harmful to nature and environment, is developed which resolves the unattractive disfigurement of building walls caused by dirt. The experimentation is scientifically and statistically planned with the aid of computer programming. It consists of a sequence of phases which include the selection of appropriate raw materials, adopting of Basic Language computer programming to generate a target population of paint formulations. The average PVC percentage is computed using theory and found to be 54.98% for the target population of 543143 paint formulations hence verifies the literature results. Experimentation and statistical analysis are performed to compare the classical conventional agitator with latest lab equipment like Nano mill and it is concluded that Nano mill performs better on the average than conventional agitator in preparation of paint formulations. Hence the sample of paint formulations is prepared on Nano mill and tested in laboratory using advanced available technology for the analysis and comparison of paint properties to determine the best paint formulation. The results are analyzed using Analysis Of Variance Technique (ANOVA) and it is concluded that the paint formulation named “O3” has the highest dirt resistance on the average. The final selected formula O3 is compared with three other competitor paints in market under natural environment for a period of almost one year. A regression model is also constructed to study the effect of environmental factors like time, temperature and humidity on dirt resistance of paints. It is found that O3 formulation is the best environment friendly which performs equally well with one competitor paint and has higher dirt resistance than two other competitor paint formulations containing harmful chemicals. The regression model of dirt resistance on variables including time, temperature and humidity shows that these factors are significantly affecting the dirt resistance of a given paint at 5% level of significance. 95.34% variation in the dirt resistance of a given paint is due to and explained by the given factors. The regression model is useful to predict the average dirt resistance of a given paint with a certain level of confidence. The project exemplifies the work of an applied research from conceptualization to successful commercialization for the paint industry.
ARTICLE | doi:10.20944/preprints201811.0387.v1
Subject: Social Sciences, Econometrics & Statistics Keywords: climate change; soybean yields; technology; temperature; CO2
Online: 16 November 2018 (07:45:34 CET)
Soybean yields are often indicated as an interesting case of climate change mitigation due to the beneficial effects of CO2 fertilization. In this paper we econometrically study this effect using a time series model of yields in a multivariate framework for a main producer and exporter of this commodity, Argentina. We have to deal with the upward behavior of soybean yields trying to identify which variables are the long-run determinants responsible of its observed trend. With this aim we adopt a partial system approach to estimate subsets of long-run relationships due to climate, technological and economic factors. Using an automatic selection algorithm we evaluate encompassing of the different obtained equilibrium correction models. We found that only technological innovations due to new crop practices and the use of modified seeds explain soybean yield in the long run. Regarding short run determinants we found positive effects associated with the use of standard fertilizers and also from changes in atmospheric CO2 concentration which would suggest a mitigation effect from global warming. However, we also found negative climate effects from periods of droughts associated with La Niña episodes, high temperatures and extreme rainfall events during the growing season of the plant.
ARTICLE | doi:10.20944/preprints201808.0440.v1
Subject: Engineering, Civil Engineering Keywords: GFRP rebars; durability; bond; temperature; surface enhancement
Online: 27 August 2018 (05:47:18 CEST)
Increased traffic in combination with growing environmental impacts, have led to accelerated degradation of the built infrastructure. In reinforced concrete structures, the corrosion of steel reinforcement is the predominant cause of deterioration. Thus, over the last years the use of glass fiber reinforced polymer (GFRP) composites as internal reinforcement bars (rebars) for concrete structures was evaluated, and has been proved to be a viable alternative to traditional steel reinforcement mainly due to its tensile strength and non-corrosive nature. However, thus far, the GFRP rebar market is diverse and manufacturers around the world produce GFRP rebar types with different surface enhancement to improve the bond to concrete characteristics. In this study, the bond performance of three dissimilar GFRP rebar types (sand coated, helically grooved and with surface lugs) was evaluated over time in seawater environments, with a focus on the bond strength. Accordingly, specimens were expose to seawater in circulating chambers, at three different temperatures (23 °C, 40 °C and 60 °C) for multiple time periods (60 and 120 days). To evaluate the bond performance, pullout tests were conducted according to ASTM D7913 . The results showed that the bond strength varies with surface enhancement features. However, the bond strength didn’t vary significantly with exposure time and temperature for all three evaluated rebar types.
ARTICLE | doi:10.20944/preprints201801.0168.v1
Subject: Chemistry, Physical Chemistry Keywords: phosphor; optical sensor; temperature sensor; manganese, luminescence
Online: 18 January 2018 (05:37:15 CET)
Phosphors based on magnesium titanate activated with Mn4+ ions are of great interest because, when excited with blue light, they display a strong red-emitting luminescence. They are characterized by a luminescence decay which is strongly temperature dependent in the range from 0 to 80 °C, making these materials very promising for temperature sensing in the biochemical field. In this work the optical and thermal properties of the luminescence of Mg2TiO4 are investigated for different Mn4+ doping concentrations. The potential of this material for temperature sensing is demonstrated by fabricating a fiber optic temperature microsensor and by comparing its performance against a standard resistance thermometer. The response of the fiber optic sensor is exceptionally fast, enabling monitoring of temperature fluctuation in subsecond time domain.
ARTICLE | doi:10.20944/preprints201712.0176.v1
Subject: Life Sciences, Biochemistry Keywords: purple sweetpotato; anthocyanin; polyphenolics; caffeoylquinic acid; temperature
Online: 25 December 2017 (10:01:14 CET)
The health benefits of purple sweetpotato, which is used as an edible food in its natural state and in processed foods and as a natural color pigment, have been recognized. In Japan, sweetpotato has been economically produced in regions below 36°4′N latitude, however, cultivation areas are beginning to expand further north. The anthocyanin and polyphenolics in purple sweetpotatoes cultivated in different locations; I (42°92′ N, 143°04′ E), II (35°99′ N, 140°01′ E), and III (31°72′ N, 131°03′ E), were compared over two years. Total anthocyanin and polyphenolic contents in purple sweetpotatoes tended to be high in location I. Their contents significantly differed over the two years in locations I and III and was dependent on temperature during cultivation. The anthocyanin and polyphenolic compositions differed between locations. The peonidin/cyanidin ratios were higher in location III compared with I and II in all varieties. The relative amount of chlorogenic acid was higher in location I, while the amount of 3,4- and 4,5-dicaffeoyolquinic acids were higher in location III, suggesting that the variability of the anthocyanin and polyphenolic content and composition was dependent on cultivation conditions. This study suggested that northern areas in Japan are an alternative production area and may yield higher amounts of anthocyanin and polyphenolics.
ARTICLE | doi:10.20944/preprints201712.0054.v1
Subject: Earth Sciences, Environmental Sciences Keywords: temperature records; homogenisation; pattern reconstruction; central Australia
Online: 11 December 2017 (05:04:17 CET)
This work presents the computation of reliable warming trends for central Australia around Alice Springs within a circle of radius 1,000 km. Between 1880 and 2011, the average warming for the centre of Australia is +0.166 ºC/century, slightly smaller than the warming of Alice Springs, that is +0.176 ºC/century. Over a shorter time between 1910 and 2011, the centre of Australia is warming +0.794 ºC/century, slightly more than the warming of Alice Springs, that is +0.719 ºC/century.
ARTICLE | doi:10.20944/preprints201707.0066.v1
Subject: Earth Sciences, Oceanography Keywords: spatial precision; sea surface temperature; VIIRS; AVHRR
Online: 24 July 2017 (12:15:05 CEST)
The primary measure of the quality of sea surface temperature (SST) fields obtained from satellite-borne infrared sensors has been the bias and variance of matchups with co-located in-situ values. Because such matchups tend to be widely separated, these bias and variance estimates are not necessarily a good measure of small scale (several pixels) gradients in these fields because one of the primary contributors to the uncertainty in satellite retrievals is atmospheric contamination, which tends to have large spatial scales compared with the pixel separation of infrared sensors. Hence, there is not a good measure to use in selecting SST fields appropriate for the study of submesoscale processes and, in particular, of processes associated with near-surface fronts, both of which have recently seen a rapid increase in interest. In this study, two methods are examined to address this problem, one based on spectra of the SST data and the other on their variograms. To evaluate the methods, instrument noise was estimated in Level-2 VIIRS and AVHRR SST fields of the Sargasso Sea. The two methods provided very nearly identical results for AVHRR: along-scan values of approximately 0.18 K for both day and night and along-track values of 0.21 K also for day and night. By contrast, the instrument noise estimated for VIIRS varied by method, scan geometry and day-night. Specifically, daytime, along-scan (along-track), spectral estimates were found to be approximately 0.05 K (0.08 K) and the corresponding nighttime values of 0.02 K (0.03 K). Daytime estimates based on the variogram were found to be 0.08 K (0.10 K) with the corresponding nighttime values of 0.04 K (0.06 K). Taken together: AVHRR instrument noise is significantly larger than VIIRS instrument noise, along-track noise is larger than along-scan noise and daytime levels are higher than nighttime levels. Given the similarity of results and the less stringent preprocessing requirements, the variogram is the preferred method although there is a suggestion that this approach overestimates the noise for high quality data in dynamically quiet regions. Finally, simulations of the impact of noise on the determination of SST gradients show that on average the gradient magnitude for typical ocean gradients will be accurately estimated with VIIRS but substantially overestimated with AVHRR.
ARTICLE | doi:10.20944/preprints201702.0014.v1
Subject: Earth Sciences, Atmospheric Science Keywords: temperature; precipitation; ethiopia; mann kendall; climate variability
Online: 5 February 2017 (08:56:29 CET)
Long term Precipitation and temperature variations are one of the main determinants of climate variability of one’s area. The aim of this study is to determine trends variation in climatic elements of temperature and precipitation in the southern zone of Tigray regional state, Ethiopia. The station is assumed for the study of climatic records over southern zone of the region in detection for probable trends. The daily, monthly and annual precipitation totals and temperature observed at korem meteorological station were used for the period of 1981-2010 for Precipitation and 1985 – 2010 for minimum and maximum temperature. Summary of descriptive statistics and Mann Kendall test methods were employed for the observed data analysis to demonstrate any existence of possible trends. The main findings of the study indicated that the mean and maximum temperature had a general increasing trend; however, minimum temperature showed decreasing trend. In general annual temperature from 1985 – 2010 of the area showed a warming trend. Moreover analysis of the 30 years (1981-2010) annual precipitation showed a coefficient of variation ranging from 33.77 – 233 %. It indicated that the precipitation dissemination is not normal with large year to year variances.
ARTICLE | doi:10.20944/preprints201610.0112.v1
Subject: Engineering, Other Keywords: silver; dissolution; thiosulfate; characterization; complex; temperature; arsenic
Online: 26 October 2016 (10:26:54 CEST)
Metallic elements of higher economic value occurring in the mineralogy of Zimapán are Pb, Zn, Cu and Fe, said elements are sold as concentrates, which, even after processing, generally include significant concentrations of Mo, Cd, Sb, Ag and As that could recover through different leaching methods. In this work the influence of temperature was studied in the complexation of silver in the S2O32--O2 system. Chemical and mineralogical characterization of concentrated Zn from the state of Hidalgo confirmed the presence of the silver contained in a sulfide of silver arsenic (AgAsS2) through the techniques of Atomic Absorption Spectrophotometry (AAS), X-Ray Diffraction (XRD) and Scanning Electron Microscopy-Energy-Dispersive X-Ray Spectroscopy (SEM-EDS). The mineralogical species identified allowed the construction mineralogical species Pourbaix diagrams in the range of 298 K to 333 K, through which the Eh-pH conditions to obtain silver in solution were determined. The formation of Ag(S2O3)23- complex was confirmed by characterizing liquors leached using the technique Infrared Spectroscopy Fourier Transform (FTIR).
ARTICLE | doi:10.20944/preprints201608.0067.v1
Online: 6 August 2016 (11:31:10 CEST)
In this study, a basic study was performed to analyze the seasonal temperature status of a research room in the Global Environment Research Building where ceiling-embedded indoor units are installed to study the room temperature status of the building as well as to improve its thermal environment. In addition, a direction for improvement of the indoor thermal environment in the winter was proposed through a CFD (computational fluid dynamics) simulation and was proven by an additional experiment. Through the results of this study, it appeared that if the ceiling-embedded indoor unit was installed in the small indoor space without considering the thermal vulnerability of its perimeter boundary, the air temperature of the upper part was greatly different from that of the bottom part in the winter. Hence, in this study, as a means to improve it, convectors were installed to minimize the effect of the external thermal environment and angle-controllable air flowing fans were installed to mitigate the stratification distribution. With such result, it was intended to present the essential data for improvement of the thermal environment as well as conservation of heating energy in the winter for buildings by reviewing the use of the ceiling-embedded indoor unit in the future.
ARTICLE | doi:10.20944/preprints202207.0269.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: Fe-based superconductor; critical temperature; transition temperature; attractive Lorentz force; Tc-dome diagram; structure transition; quantum critical point
Online: 18 July 2022 (11:03:33 CEST)
In this study, Fe-based superconductors (SCs) are described with a model showing a novel attractive force. First, we describe this novel force using an analog from electromagnetism. From electromagnetism, it was found that this force is a Lorentz force in which two electrons orbit around a Fe-ion with the same velocity. Then, we consider a wave function of an electron. Consequently, due to the property of the proposed attractive force and the quantum-field Hamiltonian, we clarified that the Bardeen–Cooper–Schrieffer (BCS) ground state can be reused. Afterward, attractive force energy was calculated according to the presented model. In Fe-based SCs, a structure transition is essential. Considering that the derived attractive force energy is relatively large, we employ the expanded Tc-equation from the BCS theory that includes the structure transition effect and the derived attractive force energy. In addition, we succeed in analytically reproducing Tc-dome diagrams in various types of Fe-based SCs. Moreover, we discuss the universal property a general SC should have as well as the quantum critical point.
ARTICLE | doi:10.20944/preprints202111.0401.v1
Subject: Biology, Ecology Keywords: water temperature; stratification; endangered fish species; thermal stress; refugia; temperature refuge; delta smelt; chinook salmon; San Francisco Estuary
Online: 22 November 2021 (14:07:45 CET)
Climate change may cause organisms to seek thermal refuge from rising temperatures, either by shifting their ranges or seeking microrefugia within their existing ranges. We evaluate the potential for thermal stratification to provide refuge for two fish species in the San Francisco Estuary (SFE): Chinook Salmon (Oncorhynchus tshawytscha) and Delta Smelt (Hypomesus transpacificus). We compiled water temperature data from multiple monitoring programs to evaluate spatial, daily, hourly, intra-annual, and inter-annual trends in stratification using generalized additive models. We used our data and models to predict the locations and periods of time that the bottom of the water column could function as thermal refuge for salmon and smelt. Periods in which the bottom was cooler than surface primarily occurred during the peak of summer and during the afternoons, with more prominent stratification during warmer years. Although the SFE is often exceedingly warm for fish species and well-mixed overall, we identified potential for thermal refugia in a long and deep terminal channel for Delta Smelt, and in the periods bordering summer for Chinook Salmon. Thermal stratification may increase as the climate warms, and pockets of cooler water at depth, though limited, may become more important for at-risk fishes in the future.
ARTICLE | doi:10.20944/preprints202208.0321.v1
Subject: Biology, Plant Sciences Keywords: 5-aminolevulinic acid; loquat; low-temperature stress; glutathione
Online: 17 August 2022 (10:33:22 CEST)
Reduced glutathione (GSH) is an antioxidant in plants and is one of the important ways for plants to combat low-temperature stress. In this paper, Eriobotrya japonica Lindl. cv. Zaozhong No. 6 seedlings were used to study the effects of exogenous 5-aminolevulinic acid (ALA) application on glutathione synthesis and cyclic metabolism of loquat seedlings under low-temperature stress and to explore the regulatory mechanism of ALA on loquat cold tolerance. The results showed that ALA treatment could increase the content of GSH and the reduced glutathione/oxidized glutathione (GSH/GSSG) ratio in loquat leaf slices under low-temperature stress; reduce the electrolyte leakage rate and GSSG, H2O2 and MDA contents in leaf tissues; and alleviate the peroxidation damage caused by low temperature. ALA treatment increased the activity of γ-glutamine synthetase (γ-ECS) in loquat leaf slices under low-temperature stress and promoted the biosynthesis of reduced glutathione, thereby increasing the GSH content in leaf tissues. On the other hand, ALA treatment could also improve the activities of glutathione reductase (GR), glutathione S-transferase (GST) and glutathione peroxidase (GPX) and promote the cyclic regeneration of GSH, accordingly maintaining a high GSH/GSSG ratio, promoting the removal of reactive oxygen species (ROS), and enhancing the antioxidant capacity of leaves. The regulatory effect of ALA on enhancing the antioxidant capacity of loquat seedlings under low-temperature stress can be inhibited by L-buthionine-sulfoximine (BSO, GSH biosynthesis inhibitor). The results showed that ALA improved the antioxidant capacity of loquat seedlings under low-temperature stress, and GSH was involved in the regulation of the antioxidant effect of ALA on loquat seedlings under low-temperature stress.
ARTICLE | doi:10.20944/preprints202112.0115.v2
Subject: Physical Sciences, Condensed Matter Physics Keywords: room temperature superconductivity; magnetic susceptibility; diamagnetism; raw data
Online: 31 December 2021 (10:13:20 CET)
In ref. , we pointed out that certain anomalies observed in the published data for ac magnetic susceptibility of a room temperature superconductor reported in Nature 586, 373 (2020)  would be cleared up once the measured raw data were made available. Part of the measured raw data were recently posted in arXiv:2111.15017 . Here we report the results of our analysis of these raw data and our conclusion that they are incompatible with the published data. Implications of these results to the claim that the material is a room temperature superconductor are discussed.
ARTICLE | doi:10.20944/preprints202104.0705.v1
Subject: Medicine & Pharmacology, Allergology Keywords: elite athletes; olympic sailors; body temperature; heat adaptation
Online: 27 April 2021 (11:41:24 CEST)
Objective On the eve of the summer Olympic Games in Tokyo research focus has shifted on the core temperature responses of elite athletes competing in the heat. In the absence of the field data of core temperature during Olympic sailing competition aim of the present study was to identify core temperature response during the Tokyo 2020 Olympic Test Event. Methods Four elite athletes from Olympic sailing (177.5±5.2 cm, 71.1±7.4 kg, body mass index 22.5±1.4 kg/m2, 24.8±3.7 yrs, VO2max 50.6±7.2 mL/min/kg)): 2 males and 2 females participated in the study. Core temperature was recorded using e-Celsius ingestible capsules, heart rate using a heart rate monitor. Ambient conditions in direct sunlight were measured using portable meteo station. Results Core temperature was recorded at water environment via an ingestible capsule in 4 sailors during the training (T), and competition (C), respectively. Ambient conditions in direct sunlight were hot and humid: during training temperature were 30.9°C±1.7°C and relative humidity 81.4%±2.8%, corresponding to a wet-bulb globe temperature of 41°C±4°C and during competition temperature was 31.2°C±2.3°C and relative humidity 87.2%±4.4%, corresponding to a wet-bulb globe temperature of 45.2°C±8.9°C. Core temperature increased during training reaching higher peak values (38.6°C±0.4°C) and during competition (38.9°C±0.4°C). The highest temperature recorded was 39.4°C (C). Conclusion The current study provides unique information into the core temperature parameters under heat stress in elite Olympic sailors during training and race event.
ARTICLE | doi:10.20944/preprints202104.0274.v1
Subject: Engineering, Construction Keywords: Waste glass; Inorganic binder; Curing temperature; Curing duration
Online: 12 April 2021 (09:38:07 CEST)
Inorganic polymeric materials react slowly at room temperature and as a result usually require high-temperature curing. This study used the Arrhenius equation to analyze the correlation between curing temperature and curing duration during high-temperature curing. The test results show that optimal values exist for each alkali equivalent of the activator (weight ratio of Na2O/glass powder), curing temperature, and curing duration. Extending the curing duration and increasing the curing temperature have positive effects when the alkali equivalent is lower than the optimal value. However, over-curing results in invisible cracking in the specimens. Furthermore, despite exhibiting high strength initially, the strength of specimens gradually diminishes after standing in air. To ensure the durability of glass-based geopolymer, the curing temperature should not exceed 70℃, and the curing duration should be less than one day.
ARTICLE | doi:10.20944/preprints202102.0271.v1
Subject: Medicine & Pharmacology, Allergology Keywords: ATR; THz; synchrotron radiation; biological tissues; temperature variation
Online: 11 February 2021 (09:29:43 CET)
A novel method of investigating the temperature dependent variation of aspects of the complex refractive index n* in samples in the THz range using continuous, non-polarised, synchrotron radiation is presented. The method relies on the use of ATR apparatus, and retains the advantage of minimal sample preparation, which is a feature of ATR techniques. The method demonstrates the viability of rapidly monitoring temperature reflectance whilst continuously heating or cooling samples by using a temperature variable Thermal Sample Stage. The method remains useful when the refractive index of the sample precludes attenuated total reflection study. This is demonstrated with the water reflectance experiments. The temperature dependent ATR reflectance of tissue-representative fats (lard and Lurpak® butter) was investigated with the novel approach. Both are within the ATR range of the diamond crystal in a “true” ATR mode. Lard showed no clear temperature variation between -15 0C and 24 0C at 0.7 to 1.15 THz or 1.70 to 2.25 THz. Lard can be regarded as having invariable, constant, dielectric properties within mixtures when biological substances are being assessed for temperature dependent dielectric variation within the stated THz ranges. Lurpak® butter (water content 14.7%) displayed temperature dependent reflectance features with a steady decline in reflectivity with increasing temperature. This is in line with the temperature-dependent behaviour of liquid water. There is no rapid change in reflectance, even at -20 0C, suggesting that emulsified water retains liquid-water-like THz properties at freezing temperatures.
ARTICLE | doi:10.20944/preprints202101.0611.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Mean surface temperature; CMIP6; evaluation; projections; East Africa
Online: 29 January 2021 (11:35:29 CET)
This study evaluates the historical mean surface temperature (hereafter T2m) and examines how T2m changes over East Africa (EA) in the 21st century using CMIP6 models. An evaluation was conducted based on mean state, trends, and statistical metrics (Bias, Correlation Coefficient, Root Mean Square Difference, and Taylor skill score). For future projections over EA, five best performing CMIP6 models (based on their performance ranking in historical mean temperature simulations) under the shared socioeconomic pathways SSP2-4.5 and SSP5-8.5 scenarios were employed. The historical simulations reveal an overestimation of the mean annual T2m cycle over the study region with fewer models depicting underestimations. Further, CMIP6 models reproduce the spatial and temporal trends within the observed range proximity. Overall, the best performing models are as follows: FGOALS-g3, HadGEM-GC31-LL, MPI-ESM2-LR, CNRM-CM6-1, and IPSL-CM6A-LR. During the three-time slice under consideration, the Multi Model Ensemble (MME) project many changes during the late period (2080 – 2100) with expected mean changes at 2.4 °C for SSP2-4.5 and 4.4 °C for the SSP5-8.5 scenario. The magnitude of change based on Sen’s slope estimator and Mann-Kendall test reveal significant increasing tendencies with projections of 0.24°C decade-1 (0.65°C decade-1) under SSP2-4.5 (SSP5-8.5) scenarios. The findings from this study illustrate higher warming in the latest model outputs of CMIP6 relative to its predecessor, despite identical instantaneous radiative forcing.
ARTICLE | doi:10.20944/preprints202011.0419.v1
Online: 16 November 2020 (12:51:44 CET)
To bring to the fore the aim of this research, effects of fluctuating temperature, was measured against food and nutrition security in the region using food production index, and undernourished population growth rate as proxies; controlled over share of arable land, irrigation, population and labour share for agriculture. Dynamic panel of generalized method of moments (GMM) was adopted, the period 2000 to 2016 were considered and 29 countries in sub-Sahara Africa were selected within the empirical framework of global water balance as mentioned by Rai and Singh (2012). Findings from the study reveals that the short run effect of temperature increase in degrees pose at least -3.1% negative and significant impact effects on the food production while the long run elasticity hits -7.5% and the controlled effect on arable land revealed a positive impact on the food production to the tune of 3.9%. Contrarily, arable land expansion reduces the under nourished population by -8.55%. Population increase on the other hand increases undernourished population in the region to the tune of 11.95%. The study therefore recommended expansion in the arable land and encourages population control policy in order to negate the undesired effects of temperature on food and nutritional security.
ARTICLE | doi:10.20944/preprints202008.0513.v1
Subject: Life Sciences, Other Keywords: heat stress; cow; automatic milking system; temperature; milk
Online: 24 August 2020 (08:15:32 CEST)
The objective of this study was to evaluate biomarkers of heat stress (HS) from automatic milking system (AMS), the relationships between measurements of temperature-humidity index (THI) and reticulorumen ph and temperature and some automatic milking systems parameters in dairy cows (rumination time (RT), milk traits, body weight (BW) and consumption of concentrate (CC)) during summer period. The experiment was carried out on a dairy farm at 54.9587408, 23.784146. Lithuanian Black and White dairy cows (n=365) were selected. The cows were milked with Lely Astronaut® A3 milking robots with free traffic. The rations were calculated to meet physiological requirements of the animals. Daily milk yield, rumination time, body weight, milk fat and protein ratio were collected from the Lely T4C management program for analysis. The pH and temperature of the contents of cow reticulorumen were measured using specific smaX-tec boluses manufactured for animal care. The daily humidity and air temperature in the farm zone were obtained from the adjacent weather station (2 km away). According this study during HS, the higher THI had positive correlation with ML, which show tendencies to increase risk of mastitis, and decrease CC, RT, BW, MY, reticulorumen ph and F/P. Some biomarkers of HS can be milk yield, milk lactose, somatic cell count, concentrate conception, rumination time, body weight, reticulorumen ph and milk fat – protein ratio. We can recommend to monitoring these parameters in the herd management program to identify possibility of heat stress.
ARTICLE | doi:10.20944/preprints202008.0405.v1
Subject: Materials Science, Nanotechnology Keywords: nonlocal nanobeam; rotation; thermoelasticity; temperature-dependent; varying load
Online: 19 August 2020 (08:57:49 CEST)
A theoretical nonlocal thermoelastic model for studying the effects of the thermal conductivity variability on a rotating nanobeam has been described in the present article. The theory of thermal stress is employed using the Euler–Bernoulli beam model and generalized heat conduction with phase lags. It is believed that the thermal conductivity of the current model varies linearly according to temperature. Due to variable harmonic heat, the considered nanobeam excited and was subjected to a time-varying exponential decay load. Using the Laplace transform process, the analytical solutions for displacement, deflection, thermodynamic temperature and bending moment of rotating nanobeams are provided in final forms and a numerical example has been taken to address the problem. A comparison of the stated results was displayed and additionally, the influences of non-local parameters and varying load were analyzed and examined. We also investigate how the linear changes in the temperature of physical properties can influence both the static and dynamic responses to the rotating nanobeam.
ARTICLE | doi:10.20944/preprints202008.0354.v1
Subject: Biology, Animal Sciences & Zoology Keywords: seahorse; effective day degrees; temperature; stable isotopes; Hippocampus
Online: 17 August 2020 (08:11:00 CEST)
Relations between nutrient assimilation and growth rate in fishes may vary with abiotic factors such as temperature. The effects of feeding status, ontogeny and temperature regimes (15, 18 and 21 °C) on stable isotope (δ13C and δ15N) patterns were assayed and modelled in juveniles of the seahorse Hippocampus guttulatus. The use of effective day degrees (D°eff) and chronological time (age) were compared as development progress indices. Newborn seahorses were maintained at three temperature levels both deprived of food (5 days) or fed (30 days) on copepods or/and Artemia. Isotopic signatures in fed seahorses clearly differed from those in unfed juveniles. Temperature had a significant effect on δ13C values in fed juveniles throughout the experimental period. δ15N values also varied significantly with age, but not with temperature level. Faster growth and food assimilation in seahorses held at 18 and 21 °C were supported by faster variations in isotopic values. Our findings demonstrate that effective day degrees should be preferred over chronological time as index of developmental progress in temperature fluctuating scenarios or for comparative studies.
ARTICLE | doi:10.20944/preprints202007.0082.v1
Online: 5 July 2020 (15:20:54 CEST)
The coronavirus disease 2019 (COVID-19), the pandemic is an unprecedented health emergency never seen in the recorded history of humankind due to its sheer scale, rapid spread, and subsequent shock to the global economy. The past respiratory viral pandemics of the 21st century (SARS-CoV-2 in 2003, Influenza AH1N1 in 2009) have revealed seasonality in environmental factors to play a role in the dynamics of their spread. Here, we report the observed state-level relationship between environmental factors such as temperature (T), relative humidity (RH), specific humidity (SH), and solar radiation (SR) on the COVID-19 spread over the Indian region. The results show that T and RH have a significant impact on the disease growth rate and doubling time. Every degree rise in temperature corresponds to a 0.99 % decrease in the number of cases and an increase in doubling time by ~ 1.13 days implying a slowing down of spread. A similar analysis for RH reveals that more moisture leads to a higher growth rate and reduced doubling time. Lower SH and higher surface-reaching SR are found to reduce the spread and increase the doubling time similar to that of temperature. The range of average state-level T (RH) encountered during this period was between 24 and 35oC (30 and 87%) which implies that environmental impact is still effective at all these T (RH) and is not limited to specific T (RH) ranges. The progression of the season towards monsoon, post-monsoon, and thereafter winter with a continuous reduction in temperature will prove a major challenge for health workers and policymakers attempting to enforce mitigation and control measures.
ARTICLE | doi:10.20944/preprints202003.0325.v1
Online: 23 March 2020 (01:30:06 CET)
The pandemic threat SARS-CoV-2 is now beyond control though the country of origin of this virus had already been limited for the new infection. Number of infected people and countries have been increasing day by day. Considering the previous pandemic flues, it is hypothesizing that COVID-19 will be reduced with warming the global environmental temperature. Therefore, the current study was aimed to analyze the effect of temperature and relative humidity (RH) on spreading of SARS-CoV-2 infection. The COVID-19 confirmed cases of 31 different states in China and 70 cities of 11 countries were obtained from several online databases. The real time temperature and humidity of the respective regions were taken from an online weather forecasting data source. Correlation analyses showed that SARS-CoV-2 infectivity and spreading negatively correlated with temperature of most of the states of China or cities of the world or in a country. The effect of humidity on COVID-19 was found to be positively correlated inside the China and difference of humidity was not found among countries and/or various regions of the world. Moreover, a minimum number of COVID-19 cases have been confirmed in the temperate regions compared to regions/countries compared to regions/countries with relatively low temperature. In conclusion, the SARS-CoV-2 infection has been found in a wide range of temperatures. It might be hypothesized that comparatively elevated air temperature could play a detrimental effect for SARS-CoV-2 spread.
ARTICLE | doi:10.20944/preprints202003.0294.v1
Subject: Earth Sciences, Atmospheric Science Keywords: remote sensing; precipitation; temperature; GSMaP_Gauge; CHIRPS; CFSR; SWAT
Online: 19 March 2020 (02:37:37 CET)
Precipitation and temperature are significant inputs for hydrological models. Currently, many satellite and reanalysis precipitation and air temperature datasets exist at different spatio-temporal resolutions at a global and quasi-global scale. This study evaluated the performances of three open-access precipitation datasets (gauge-adjusted research-grade Global Satellite Mapping of Precipitation (GSMaP_Gauge), Climate Hazards Group Infrared Precipitation with Station data (CHIRPS), Climate Forecast System Reanalysis(CFSR)) and CFSR air temperature dataset in driving the Soil and Water Assessment Tool (SWAT) model required for the monthly simulation of streamflow in the upper Shiyang River Basin of northwest China. After a thorough comparison of six model scenarios with different combinations of precipitation and air temperature inputs, the following conclusions were drawn: (1) Although the precipitation products had similar spatial patterns, however, CFSR differs significantly by showing an overestimation; (2) CFSR air temperature yielded almost identical performance in the streamflow simulation than the measured air temperature from gauge stations; (3) among the three open-access precipitation datasets, CHIRPS produced the best performance. These results suggested that the CHIRPS precipitation and CFSR air temperature datasets which are available at high spatial resolution (0.05), could be a promising alternative open-access data source for streamflow simulation in the case of limited access to desirable gauge data in the data-scarce area.
ARTICLE | doi:10.20944/preprints202003.0123.v1
Subject: Earth Sciences, Atmospheric Science Keywords: climate change; temperature; precipitation; anomaly; trends; Zacatecas; Mexico
Online: 7 March 2020 (15:56:50 CET)
Sufficient evidence is currently available to demonstrate the reality of the warming of our planet's climate system. Global warming has different effects on climate at the regional and local levels. The detection of changes in extreme events using instrumental data provides further evidence of such warming and allows for the characterization of its local manifestations. The present study analyzes changes in temperature and precipitation extremes in the Mexican state of Zacatecas using climate change indices developed by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDI). We studied a 40-year period (1976-2015) using annual and seasonal time scales. Maximum and minimum temperature data were used, as well as precipitation statistics from the Mexican climatology database (CLICOM) provided by the Mexican meteorological service. Weather stations with at least 80% of data availability for the selected study period were selected; these databases were subjected to quality control, homogenization, and data filling using Climatol, which runs in the R programming language. These homogenized series were used to obtain daily grides of the three variables at a resolution of 1.3 km. Results reveal important changes in temperature-related indices, such as the increase in maximum temperature and the decrease in minimum temperature. Irregular variability was observed in the case of precipitation, which could be associated with low-frequency oscillations such as the Pacific Decadal Oscillation and the El Niño–Southern Oscillation. The possible impact of these changes in temperature and the increased irregularity of precipitation could have a negative impact on the agricultural sector, especially given that the state of Zacatecas is the largest national bean producer. The most important problems in the short term will be related to the difficulty of adapting to these rapid changes and the new climate scenario, which will pose new challenges in the future.
ARTICLE | doi:10.20944/preprints201912.0313.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: near-room-temperature superconductivity; hydride superconductors; yttrium superhydrides
Online: 24 December 2019 (08:47:09 CET)
Recently, Troyan et al (2019 arXiv:1908.01534) and Kong et al (2019 arXiv:1909.10482) extended near-room-temperature superconductors family by new yttrium superhydride polymorphs, YHn (n = 4,6,7,9), which exhibit superconducting transition temperatures in the range of Tc = 210-243 K at pressure of P = 160-255 GPa. In this paper, temperature dependent upper critical field data, Bc2(T), for highly-compressed mixture of YH4+YH6 phases (reported by Kong et al 2019 arXiv:1909.10482) is analysed to deduce the ratio of Tc to the Fermi temperature, TF. Our analysis shows that in all considered scenarios the YH4+YH6 mixture has the ratio 0.01 ≤ Tc/TF ≤ 0.04. As the result, YH4+YH6 falls in the unconventional superconductors band in the Uemura plot. It is also found that the characteristic temperature of the order parameter amplitude fluctuations, Tfluc, in the YH4+YH6 mixture is only several percent above observed Tc, and thus the superconducting transition in yttrium superhydride polymorphs is fundamentally limited by thermodynamics fluctuations.
ARTICLE | doi:10.3390/sci1020049
Online: 14 August 2019 (00:00:00 CEST)
Study of spatiotemporal dynamics of temperature is vital to assess changes in climate, especially in the Himalayan region where livelihoods of billions of people living downstream depends on water coming from the melting of snow and glacier ice. To this end, temperature trend analysis is carried out in Narayani river basin, a major river basin of Nepal characterized by three climatic regions: tropical, subtropical and alpine. Temperature data from six stations located within the basin were analyzed. The elevation of these stations ranges from 460 to 3800 m a.s.l. and the time period of available temperature data ranges from 1960–2015. Multiple regression and empirical mode decomposition (EMD) methods were applied to fill in missing data and to detect trends. Annual as well as seasonal trends were analyzed and a Mann-Kendall test was employed to test the statistical significance of detected trends. Results indicate significant cooling trends before 1970s, and warming trends after 1970s in the majority of the stations. The warming trends range from 0.028
" style="position: relative;">∘C year ∘ " style="position: relative;">−1 to 0.035 − 1 " style="position: relative;">∘C year ∘ " style="position: relative;">−1 with a mean increasing trend of 0.03 − 1 " style="position: relative;">∘C year ∘ " style="position: relative;">−1 after 1971. Seasonal trends show highest warming trends in the monsoon season followed by winter, pre-monsoon, and the post-monsoon season. However, difference in warming rates between different seasons was not significant. An average temperature lapse rate of −0.006 − 1 " style="position: relative;">∘C m ∘ " style="position: relative;">−1 with the steepest value (−0.0064 − 1 " style="position: relative;">∘C m ∘ " style="position: relative;">−1) in pre-monsoon season and least negative (−0.0052 − 1 " style="position: relative;">∘C m ∘ " style="position: relative;">−1) in winter season was observed for this basin. A comparative analysis of the gap-filled data with freely available global climate datasets show reasonable correlation thus confirming the suitability of the gap filling methods.
ARTICLE | doi:10.20944/preprints201906.0281.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: perovskite solar cells; operating temperature; interface passivation; degradation
Online: 27 June 2019 (06:15:59 CEST)
In this paper, by developing a mathematical model, the operating temperature of perovskite solar cells (PSCs) under different operating conditions has been calculated. It is found that by reducing the density of tail states at the interfaces, acting as recombination centres, through some passivation mechanisms, the operating temperature can be reduced significantly at higher applied voltages. The results show that if the density of tail states at the interfaces is reduced by three orders of magnitude through some passivation mechanisms, then the active layer may not undergo any phase change up to an ambient temperature 300 K and it may not degrade up to 320 K. The calculated heat generation at the interfaces at different applied voltages with and without passivation shows that the heat generation can be reduced by passivating the interfaces. It is expected that this study may provide a deeper understanding of the influence of interface passivation on the operating temperature of PSCs.
ARTICLE | doi:10.20944/preprints201901.0084.v1
Subject: Materials Science, General Materials Science Keywords: Phase change; Composite, Thermal expansion; High temperature; Concrete
Online: 9 January 2019 (12:48:32 CET)
The expansion of concrete subjected to extreme elevated temperature is linked with intricate micro-structural variations, such as the transformation of the constituent phases. This study proposes a model to predict the thermal expansion of cement paste and concrete considering micro-structural changes under elevated temperatures ranging from 20°C to 800°C. The model presented can consider characteristics of various aggregates in the calculation of thermal expansion for concrete. The model is a combination of a multi-scale stoichiometric model and a multi-scale composite model. At the cement paste level, the model satisfactorily predicted a test result. At concrete level, upper bounds from the model were matched relatively well with test results by previous researcher. If the mechanical properties, such as elastic modulus (E), Poisson’s ratio (ν), and thermal deformation, of the aggregates used in concrete are given, it is likely that the model will reasonably predict experimental results.
ARTICLE | doi:10.20944/preprints201810.0248.v2
Subject: Materials Science, Surfaces, Coatings & Films Keywords: low temperature carburizing; XRD; optical microscopy; carburized layer
Online: 22 October 2018 (11:19:18 CEST)
Carburizing of stainless steels at low temperatures (below 500°C) develops a high content carbon layer, known for its high hardness. X-ray Diffraction investigation indicates that carburization treatment does not impact the structure of substrate; however, introduced carbon causes expansion in the carburized layer through the increase in d-spacing. Characterization of carbon concentration and hardness profiles indicate that carbon content gradually decreases while moving further into the substrate; and the origin of the increased hardness of the expanded layer arises from the super-saturated carbon content, following the solid solution strengthening theory. An area that is not well understood is in regard to the carburized layer’s relation to the substrate and the significance in their differences. Using two grades of stainless steel, AISI 316L and PH 17-4, it was observed that the carburized layer is not a separate layer, but a higher carbon content version of the substrate,
ARTICLE | doi:10.20944/preprints201808.0311.v2
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: machining; titanium; temperature; strain; grain refinement; ultrafine; nanocrystalline
Online: 11 September 2018 (09:03:57 CEST)
New metastable β titanium alloys are receiving increasing attention due to their excellent biomechanical properties and machinability is critical to their uptake. In this study machining chip microstructure have been investigated to gain an understanding of strain and temperature fields during cutting. For higher cutting speeds, ≥60 m/min, the chips have segmented morphologies characterised by a serrated appearance. High levels of strain in the primary shear zone promote formation of expanded shear band regions between segments which exhibit intensive refinement of the β phase down to grain sizes below 100 nm. The presence of both α and β phases across the expanded shear band suggests that temperatures during cutting are in the range of 400–600 °C. For the secondary shear zone, very large strains at the cutting interface result in heavily refined and approximately equiaxed nanocrystalline β grains with sizes around 20–50 nm, while further from the interface the β grains become highly elongated in the shear direction. An absence of the α phase in the region immediately adjacent to the cutting interface indicates recrystallization during cutting and temperatures in excess of the 720 °C β transus temperature.
ARTICLE | doi:10.20944/preprints201809.0190.v1
Subject: Earth Sciences, Geochemistry & Petrology Keywords: zeolite; ion-exchange; adsorption; ammonium; Si/Al; temperature
Online: 11 September 2018 (08:50:29 CEST)
We investigate the ammonium removal abilities of natural and synthetic zeolites, which have distinct Si/Al ratios and various surface areas, to study how adsorption and ion-exchange processes in zeolites perform under different ammonium concentrations and different temperatures. Five zeolites including natural mordenite, chabazite, erionite, clinoptilolite and synthetic merlinoite were immersed in 20 mg/kg, 50 mg/kg and 100 mg/kg ammonium solutions. The results demonstrate that zeolites under high ammonium concentrations (100 mg/kg) possess higher physical adsorption capacity (0.398–0.468 meq/g), whereas those under lower ammonium concentrations (20 mg/kg) possess greater ion-exchange property (64–99%). The ion-exchange ability of zeolites are extremely dependent on the cation content of the zeolites, and the cation content is affected by the Si/Al ratio. The surface area of zeolites also has a partial influence on its physical adsorption ability. When the surface area is less than 100 m2/g, the adsorption ability of zeolite increases obviously with surface area; however, adsorption ability is saturated as the surface area becomes larger than this critical value of 100 m2/g. When we carried out the zeolites in 50 mg/kg ammonium concentration at different temperatures (5~50 ℃), we found that zeolites exhibit the highest ammonium removal ability at 30°C and the potassium release was enhanced at 30~40 ℃.
ARTICLE | doi:10.20944/preprints201806.0183.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: FeSe2; high pressure; low temperature; single crystal diffraction
Online: 12 June 2018 (10:25:24 CEST)
We conducted an in-situ crystal structure analysis of ferroselite at non-ambient conditions. The aim is to provide a solid ground to further the understanding of the properties of this material in a broad range of conditions. Ferroselite, marcasite-type FeSe2, was studied under high pressures up to 46 GPa and low temperatures, down to 50 K using single-crystal microdiffraction techniques. High pressure and low temperatures were generated using a diamond anvil cell and a cryostat. We found no evidences of structural instability in the explored P-T space. The deformation of the orthorhombic lattice is slightly anisotropic. As expected, the compressibility of the Se-Se dumbbell, the longer bond in the structure, is larger than that of the Fe-Se bonds. Less obvious is the behavior of the octahedral bonds, the shorter bond is the most compressible determining a small increase in the octahedron distortion with pressure. We also achieved a robust structural analysis of ferroselite at low temperature in the diamond anvil cell. Structural changes upon temperature decrease are small but qualitatively similar to those produced by pressure.
ARTICLE | doi:10.20944/preprints201711.0080.v1
Subject: Materials Science, Surfaces, Coatings & Films Keywords: PVDF membrane; coagulation bath temperature; polymer molecular weight
Online: 14 November 2017 (10:48:54 CET)
The global polyvinyldene flouride market is estimated to reach $937,278.5 thousand by 2019, therefore to develop new membranes and gain pioneering ideas, which could create innovative business opportunities, a fundamental knowledge about membrane properties fabricated from recent commercially available PVDF polymers is highly mandatory. In this study, we successfully prepared nine non-woven supported PVDF membranes using a phase inversion precipitation method starting from a 15 wt% PVDF solution in N-methyl-2-pyrrolidone. Various membrane morphologies were obtained by using (1) PVDF polymers with diverse molecular weight in a range from 300.000 Da to 700.000 Da and (2) different temperatures of the coagulation bath (20, 40, and 60 ±2°C) used for the films precipitation. Environmental Scanning Electron Microscope (ESEM) was used for surface and cross-section morphologies characterization. Atomic Force Microscope (AFM) was employed to investigate surface roughness, while Contact Angle (CA) instrument was used for membranes wettability studies. Fourier Transform Infrared Spectroscopy (FTIR) results show that the fabricated membranes are formed by a mixture of TGTG’ chains in α phase crystalline domains and all-TTTT trans planar zigzag chains characteristic to β phase. Moreover, generated results indicate that the phases content and membrane morphologies depend on the polymer molecular weight and conditions used for the membranes preparation. The diversity of fabricated membranes could be applied by the End User Industries for different applications.
ARTICLE | doi:10.20944/preprints201709.0114.v1
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: WSN; IoT; seawater temperature prediction; marine aquaculture support
Online: 23 September 2017 (11:31:13 CEST)
Aquaculture is growing ever more important due to the decrease in natural marine resources and increase inworldwide demand. To avoid losses due to aging and abnormalweather, it is important to predict seawater temperature in order to maintain a more stable supply, particularly for high value added products, such as pearls and scallops. The increase in species extinction is a prominent societal issue. Furthermore, in order to maintain a stable quality of farmed fishery, water temperature should be measured daily and farming methods altered according to seasonal stresses. In this paper, we propose an algorithm to estimate seawater temperature in marine aquaculture by combining seawater temperature data and actual weather data.
REVIEW | doi:10.20944/preprints201705.0021.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: machine tool metrology; temperature; uncertainty; traceability; error sources
Online: 2 May 2017 (04:35:18 CEST)
Errors during manufacture of high value components are not acceptable nowadays in driving industries such as energy and transportation. Sectors such as aerospace, automotive, shipbuilding, nuclear power, large science facilities or wind power manufacture complex and accurate components that demand close measurements and fast feedback into manufacturing processes. New measuring technologies are already available in machine tools, including integrated touch probes and fast interface capabilities. They shall provide the possibility to measure the workpiece during or after the manufacturing process, maintaining the original setup of the workpiece and avoiding the manufacturing process from being interrupted to transport the workpiece to a measuring position. However, the traceability of the measurement process on a machine tool is not ensured yet and measurement data is still not fully reliable for process control or product validation. Due to the similarity between a coordinate measuring machine and a machine tool, some of the methods applied for a correct assessment of uncertainty in coordinate measuring machines are adapted to the challenges of a machine tool. The scientific objective is to determine the uncertainty on a machine tool measurement and, in this way, convert it into a machine integrated traceable measuring process. This paper reviews the fundamentals of machine tool metrology.
ARTICLE | doi:10.20944/preprints202205.0195.v1
Subject: Engineering, Civil Engineering Keywords: Reinforced Concrete; Raft Foundation; Temperature Effects; Finite Element Modelling
Online: 16 May 2022 (03:59:22 CEST)
This article presents a case study on the structural assessment of a reinforced concrete (RC) foundation exposed to low temperatures. The foundation supports a 19,500 m³-capacity tank with low-temperature (-89°C) ethane. Icing and bubbling were observed on the tank’s surface soon after it started operations. Condensation was also observed at the bottom of the 0.8 m-depth RC slab, which raised concerns about the structural condition of the concrete. This study provides details of the field and analytical investigations conducted to assess the structural condition of the foundation. Heat transfer finite element (FE) analyses were performed to examine the concrete sections subjected to low temperatures. It was found that the ethane leakage produced a low temperature on the top side of the concrete foundation of +9.7°C. Overall, the temperatures calculated by the FE analyses were in good agreement with actual field measurements, within a ±5% accuracy. The simplified heat transfer equation for porous media used in this study was sufficiently accurate to model the effects of the ethane leakage in the concrete foundation, provided the ambient temperature at the site is taken into account in the analysis. The results also confirm that reinforcing bars can be neglected in the thermal analysis of massive concrete slabs. The results from the field measurements and FE analyses confirmed that the structural integrity of the RC foundation was never compromised. The approaches, methods and techniques discussed in this article are deemed suitable to solve the practical and scientific challenges involved in the structural assessment and repairs of large special structures. Accordingly, they can serve as useful reference and guidance for engineers and practitioners working in the field of forensic engineering.
ARTICLE | doi:10.20944/preprints202204.0089.v1
Subject: Earth Sciences, Environmental Sciences Keywords: climatology; paleoclimatology; temperature; precipitation; climographs; elevational gradients; global warming
Online: 11 April 2022 (08:57:11 CEST)
The varved sediments of the Pyrenean Lake Montcortès (Pallars Sobirà, Lleida) embody a unique continuous high-resolution (annual) paleoarchive of the last 3000 years for the circum-Mediterranean region. A variety of paleoclimatic and paleoecological records have been retrieved from these uncommon sediments that have turned the lake into a regional reference. Present-day geographical, geological, ecological and limnological features of the lake and its surroundings are reasonably well known but the lack of a local weather station has prevented characterization of current climate, which is important to develop modern-analog studies for paleoclimatic reconstruction and to forecast the potential impacts of future global warming. Here, the local climate of the Montcortès area for the period 1955-2020 is characterized using a network of nearby stations situated along an elevational transect in the same river basin of the lake. The finding of statistically significant elevational gradients for annual and monthly average temperature and precipitation has enabled to estimate these parameters and their seasonal regime for the lake site. A representative climograph has been shaped with these data that can serve as a synthetic descriptive and comparative climatic tool. The same analysis has provided climatic data for modern-analog studies useful to improve the interpretation of sedimentary records in climatic and ecological terms. In addition, the seasonal slope shifting of the climatic elevational gradients has been useful to gain insights about possible future climatic trends under a warming scenario.
ARTICLE | doi:10.20944/preprints202202.0026.v1
Subject: Physical Sciences, Astronomy & Astrophysics Keywords: Neutrino, Dark Matter, Dark Energy, Black Holes, Negative Temperature
Online: 2 February 2022 (09:35:52 CET)
It is proven that the Clapeyron-Mendeleev equation, originally discovered for gases with large entropy, describes the state of dark matter and energy due to enormous self-gravitation. It is shown that the dark matter exists as compact cold neutrino stars at positive temperature with size twice the Schwarzschild radius. In contrast, the dark energy is dark matter at temperature below the absolute zero, which is locked entirely in black holes, where the pressure is negative as required for the Universe intrinsic expansion. The derived dark phase diagram predicts negative critical temperatures for the Big Bang and the Big Rip of black holes.
ARTICLE | doi:10.20944/preprints202110.0356.v1
Subject: Engineering, Automotive Engineering Keywords: Deep learning; HVAC; Cabin air temperature; Driver behvaiour; NARX
Online: 25 October 2021 (13:29:38 CEST)
The vehicular technology has integrated many features in the system, which enhances the safety and comfort of the user. Among these features, heating, ventilation, and air conditioning (HVAC) is the only feature that maintains the set cabin air temperature (CAT). The user’s command drives the set CAT, and the thermostat provides feedback to the HVAC to maintain the set CAT. The CAT is increased by extracting the heat from the engine surface produced by the fuel combustion, whereas the CAT is reduced by the known processes of the air conditioning system (ACS). Therefore, the CAT driven by the user’s command may not be optimal, and estimating the optimal CAT is still unsolved. In this work, the user was allowed to input a range for CAT instead of a single value. Optimal HVAC criteria were defined, and the CAT was estimated by performing iterative analysis in the user-selected range satisfying the criteria. The HVAC criteria were defined based on two measurable parameters: air conditioning refrigerant fluid pressure (ACRFP) and engine surface temperature (EST) empirically defined as the vector CATOP. In this article, a NARX DL model by mapping the vehicle-level vectors (VLV) to predict the CATOP in real-time using field data obtained from a 2020 Cadillac CT5 test vehicle. Utilising the DL model, CATOP for future time steps were predicted by varying the CAT in the definite range and applying HVAC criteria. Thus, an optimal set CAT was estimated, corresponding to the optimal CATOP defined by the HVAC criteria. We performed the validation of the DL model for multiple datasets using traditional statistical techniques, namely, signal-to-noise ratio (SNR) values, first-order derivatives (FOD), and root-mean-square error (RMSE).
ARTICLE | doi:10.20944/preprints202108.0266.v1
Subject: Earth Sciences, Environmental Sciences Keywords: oil palm; modeling; climate; temperature; rainfall; sunshine; wind; humidity
Online: 11 August 2021 (15:44:03 CEST)
Oil palm is one of the most important crops in Malaysia. Lately, the production of oil palm has been reduced due to a variety of factors, including the weather and climate. Temperature, wind speed, relative humidity, sunshine, and rainfall distribution all have an impact on palm tree growth and development, which in turn has an impact on oil palm production. This paper aims to investigate the effects of some weather elements (temperature, wind speed, relative humidity, sunshine, and rainfall) on oil palm production in Peninsular Malaysia. Data were analyzed using the Statistical Package for Social Sciences (SPSS 20.0 version), with descriptive statistics, and multiple linear regression (MLR). The MLR model determined the strength of the relationship between oil palm yield (dependent variable) and the changing variables of temperature, sunshine, wind speed, relative humidity, and rainfall (independent variables). The findings revealed that temperature, wind speed, relative humidity, sunshine, and rainfall have a low impact on oil palm production and yield turnover. The R2 value of 0.202 shows that the independent variables explained only 20.2% of the fluctuation in palm oil production. The study recommends working within an integrated approach involving scientific research, planting, improving variety, improving regional academic leadership, and engaging private and public stakeholders, emphasized collaborative efforts with researchers in consumer countries, and strengthening the capacity of growers to best agroecological practices.
ARTICLE | doi:10.20944/preprints202105.0763.v1
Subject: Materials Science, Biomaterials Keywords: MMCs; CMCs, Aerospace; Wetting at high temperature; Ti-Silicides.
Online: 31 May 2021 (12:11:47 CEST)
To design properly and optimizate liquid-assisted processes such as reactive infiltration for fabricating light weight and corrosion resistant SiC/TiSi2 composites, the interfacial phenomena taking place when liquid Si-rich Si-Ti alloys are in contact with glassy carbon (GC) were investigated for the first time by wetting tests performed by both the sessile and pendant drop methods at T = 1450°C. Specifically, two different Si-rich Si-Ti alloys were selected, and the obtained results in terms of contact angle values, spreading kinetics, reactivity, and developed interface microstructures were compared with experimental observations previously obtained for the liquid Si-rich Si-Ti eutectics processed under the same operating conditions. The increase of the Si content did not affected the final contact angle values. Contrarily, the final developed microstructure at the interface as well as the spreading kinetics were observed as weakly dependent on the composition. From the practical point of view, Si-Ti alloy compositions with a Si-content falling in the simple eutectic region of the phase diagram might be potentially used as infiltrant materials of C- and SiC-based composites.
ARTICLE | doi:10.20944/preprints202105.0536.v1
Subject: Biology, Anatomy & Morphology Keywords: Argan biosphere reserve; Climate change; Rainfall; Temperature; Woodland regression
Online: 24 May 2021 (07:44:25 CEST)
This paper explores the effect of climate change on the regression of the Argan tree (Argania spinosa L. Skeels) woodland, focusing on the Argan Biosphere Reserve and especially in the Souss plain (Western Morocco). Rainfall and temperature data of four sites within the Argan Biosphere Reserve were analyzed over the last 60 years to assess any climatic change. Regression curves applied to the dataset showed an important decrease in rainfall (18 to 26 %) in the four locations as well as an increase in temperature (1 to 2 °C). These changes may have a detrimental effect on the Argan woodland although human factors have been reported to be the main factor of its regression. It can therefore be concluded that the reduction in rainfall and the increase in temperature should now be considered as factors of Argan woodland regression.
ARTICLE | doi:10.20944/preprints202105.0256.v1
Subject: Earth Sciences, Atmospheric Science Keywords: reversible electrodialysis; water scarcity; process efficiency; temperature effect; voltage
Online: 12 May 2021 (07:25:01 CEST)
Currently, a large part of the wells for agricultural use located in the state of Sonora are overexploited, which generates a high degree of saline intrusion and abandonment by nearby communities. In this paper the temperature effect on the final concentration of permeate water was evaluated through voltage and intel concentration variations in a batch electrodialysis reversal process (EDR), in order to identify optimal operating conditions with emphasis on the reduction of energy consumption and cost of desalinated water. Thirty-six samples were prepared: eighteen 2,000 mg/L total dissolved solids (TDS) samples and eighteen 5,000 mg/L TDS samples; brackish well water of 639 mg/L TDS and synthetic salt were mixed to obtain those concentrations. 3 different temperatures (25, 30, 35 °C) and 2 different voltages (10 and 20 V) were tested for each sample. The best salt removal occurred in the 20 V arrays, with 18.34% higher removal for 2,000 mg/L TDS experiments and 25.05% for 5,000 mg/L experiments (average between the 25 to 35 °C tests). Temperature positively affected EDR, especially in the experiments at 10 V voltage, where increasing 10 °C increased its efficiency by 10.83% and 24.69% for 2,000 and 5,000 mg/L TDS, respectively. Energy consumption was lower with increasing temperature (35 °C), as it decreased by 1.405% and 1.613% for 2,000 and 5,000 mg/L TDS concentrations, respectively (average between 10 and 20 V tests), decreasing the cost per m3 of water.
ARTICLE | doi:10.20944/preprints202104.0158.v1
Subject: Mathematics & Computer Science, Artificial Intelligence & Robotics Keywords: Organic Solar Cells; Triple Junction; Tandem, Energy Harvesting; Temperature.
Online: 6 April 2021 (09:21:56 CEST)
The organic solar cells (OSCs) have drawn attention in the past decade due to its cynosure in industrial manufacturing because of its promising properties such as low weight, highly flexible and low cost production. However, low η restricts the utilization of OSCs for potential application such as low cost energy harvesting devices. In this paper, OSCs structure based on triple junction tandem scheme is reported with three different absorber materials with the objective to enhance the absorption of photons which in turn improves the η, as well as its correlating performance parameters. The investigated structure gives the higher value of η = 14.33% with Jsc=16.87 (mA/m2), Voc=1.0 (V), and FF=84.97% by utilizing a stack of three different absorber layers with different band energies. The proposed structure is tested under 1.5 (AM) with 1 sun (W/m2). The impact of top, middle and bottom sub cells thickness on η is analyzed with a terse to find the optimum thickness for three sub cells to extract high η. The optimized structure is then tested with different electrode combination and the highest η is recorded with FTO/Ag. Moreover, the influence of upsurge temperature is also demonstrated on the proposed structure and observed that the upsurge temperature has greatly affected the electrical parameters of the device and η decreases from 14.33% to 11.40% when the temperature of the device rises from 300-400 K.
ARTICLE | doi:10.20944/preprints202104.0145.v1
Subject: Earth Sciences, Atmospheric Science Keywords: COVID-19; environment; CO2 emission; temperature; NO2 emission; energy
Online: 5 April 2021 (14:27:28 CEST)
Coronavirus disease is a newly identified infectious disease that began in Wuhan, China in 2019 and is recognized as COVID-19. This virus has a serious impact on the planet that causes the deaths of millions of people; it produces unemployment and poverty. However, it has constructive environmental effects that reduce the amount of pollution in the atmosphere. Pakistan is also a developing economy caused by this deadly virus. Before 03 April 2021, the percentage of reported cases ranges from 682,888, with about 14,697 casualties and a total of 609,691 cases retrieved. Pakistan’s war against coronavirus can differ from advanced technical countries due to lack of resources. In this article, we will address the relation between COVID-19 and the environment in the particular case of Pakistan. There is evidence that this pandemic has lowered concentrations of greenhouse gases, including CO2 and NO2, as a consequence of global lock-down strategies.
ARTICLE | doi:10.20944/preprints202103.0244.v1
Subject: Earth Sciences, Atmospheric Science Keywords: land surface temperature (LST); NDVI; NDBaI; MNDWI; Satellite data
Online: 9 March 2021 (09:17:02 CET)
Analysis of the correlation between indices (Normalized Difference Vegetation Index, Normalized Difference Barren Index and Modified Normalized Difference Water Index) and land surface temperature is used to natural resources and environmental studies. This research aimed to analysis of Land Surface Temperature due to dynamics of Different Indices (NDVI, NDBaI and MNDWI) Using Remote Sensing Data in three selected districts (Gida Kiremu, Limu and Amuru), western Ethiopia. From thermal and multispectral bands of landsat imageries (Landsat TM of 1990, landsat ETM+ of 2003 and landsat OLI/TIRS of 2020) Land surface temperature and NDVI, NDBaI and MNDWI were calculated. Correlation analysis was used to indicate relationships between LST with NDVI, NDBaI and MNDWI. The study found that Land Surface Temperature was increased by 50C from 1990 to 2020. Vegetation areas (NDVI) and Water bodies (MNDWI) have strong negative relationship with Land Surface Temperature (R2= 0.99, 0.95) whereas Barren land (NDBaI) has positive relationship with Land Surface Temperature (R2= 0.96). Finally, we recommend the decision makers and environmental analyst to emphasis the importance of vegetation cover and water body to minimize the potential impacts of land surface temperature.
ARTICLE | doi:10.20944/preprints202012.0077.v1
Subject: Life Sciences, Biochemistry Keywords: Cuticular wax; dehydration; low temperature; freezing, stress avoidance; alkane
Online: 3 December 2020 (09:54:39 CET)
Cuticular waxes are a mixture of hydrophobic very-long-chain fatty acids and their derivatives accumulated in the plant cuticle. Most studies define the role of cuticular wax largely based on reducing non-stomatal water loss. The present study investigated the role of cuticular wax in reducing both low-temperature and dehydration stress in plants using Arabidopsis thaliana mutants and transgenic genotypes altered in the formation of cuticular wax. cer3-6, a known Arabidopsis wax-deficient mutant (with distinct reduction in aldehydes, n-alkanes, secondary n-alcohols, and ketones compared to wild type (WT)), was most sensitive to water loss; while dewax, a known wax overproducer (greater alkanes and ketones compared to WT), was more resistant to dehydration compared to WT. Furthermore, cold-acclimated cer3-6 froze at warmer temperatures, while cold-acclimated dewax displayed freezing exotherms at colder temperatures compared to WT. GC-MS analysis identified a characteristic decrease in the accumulation of certain waxes (e.g. alkanes, alcohols) in Arabidopsis cuticles under cold acclimation, which was additionally reduced in cer3-6. Conversely, the dewax mutant showed a greater ability to accumulate waxes under cold acclimation. FTIR spectroscopy also supported observations in cuticular wax deposition under cold acclimation. Our data indicate cuticular alkane waxes along with alcohols and fatty acids can facilitate avoidance of both ice formation and leaf water loss under dehydration stress, and are promising genetic targets of interest.
ARTICLE | doi:10.20944/preprints202009.0563.v1
Subject: Life Sciences, Other Keywords: plant development rate; temperature-dependent; landscape; multi-location trials
Online: 24 September 2020 (04:33:34 CEST)
Understanding the detailed timing of crop phenology and their variability enhances grain yield and quality by providing precise scheduling of irrigation, fertilization, and crop protection mechanisms. Advances in information and communication technology (ICT) provide a unique opportunity to develop agriculture-related tools that enhance wall-to-wall upscaling of data outputs from point-location data to wide-area spatial scales. Because of the heterogeneity of the worldwide agro-ecological zones where crops are cultivated, it is unproductive to perform plant phenology research without providing means to upscale results to landscape-level while safeguarding field-scale relevance. This paper presents an advanced, reproducible, and open-source software for plant phenology prediction and mapping (PPMaP) that inputs data obtained from multi-location field experiments to derive models for any crop variety. This information can then be applied consecutively at a localized grid within a spatial framework to produce plant phenology predictions at the landscape level. This software supports the development of process-oriented and temperature-driven plant phenology models by intuitively and interactively leading the user through a step-by-step progression to the production of spatial maps for any region of interest. Maize (Zea mays L.) was used to demonstrate the robustness, versatility, and high computing efficiency of the resulting modeling outputs of the PPMaP. The framework is implemented in R, providing a flexible and easy‐to‐use GUI interface. Since this allows appropriate scaling to the larger spatial domain, the software can effectively be used to determine the spatially explicit length of growing period (LGP) of any variety.
ARTICLE | doi:10.20944/preprints202007.0165.v1
Subject: Earth Sciences, Geophysics Keywords: Lake Urmia; Local climate; Temperature adjustment; lake/land breeze
Online: 9 July 2020 (02:07:35 CEST)
Lake Urmia in northwestern Iran is the largest lake in Iran and the second largest saltwater lake in the world. The water level in Lake Urmia has decreased dramatically in recent years, due to drought, climate change, and overuse of water resources for irrigation. This shrinking of the lake may affect local climate conditions, assuming that the lake itself affects the local climate. In this study, we quantified the lake’s impact on the local climate by analyzing hourly time series of data on climate variables (temperature, vapor pressure, relative humidity, evaporation, and dewpoint temperature for all seasons, and local lake/land breezes in summer) for the period 1961-2016. For this, we compared high quality, long-term climate data obtained from Urmia and Saqez meteorological stations, located 30 km and 185 km from the lake center, respectively. We then investigated the effect of lake level decrease on the climate variables by dividing the data into 1961-1995 (normal lake level) and 1996-2016 (low lake level). The results showed that at Urmia station (close to the lake), climate parameters displayed fewer fluctuations and were evidently affected by Lake Urmia compared with those at Saqez station. The effects of the lake on the local climate increased with increasing temperature, with the most significant impact in summer and the least in winter. The results also indicated that, despite decreasing lake level, local climate conditions are still influenced by Lake Urmia, but to a lesser extent.
COMMUNICATION | doi:10.20944/preprints201910.0352.v1
Subject: Chemistry, Food Chemistry Keywords: coffee; espresso; hot beverages; temperature; esophageal cancer; sensory trial
Online: 30 October 2019 (09:12:32 CET)
Very hot (> 65 °C) beverages such as espresso were evaluated by the International Agency for Research on Cancer (IARC) as probably carcinogenic to humans. For this reason, research into lowering beverage temperature without compromising its quality or taste is important. For espresso, one obvious possibility consists in lowering the brewing temperature. In two sensory trials using ISO 4120:2004 triangle test methodology, brewing temperatures of 80°C vs. 128°C and 80° vs. 93°C were compared. From the tested levels, espresso brewed at the lowest temperature had the highest acceptance. However, most tasters were unable to distinguish between 80°C and 93°C. The results of these pilot experiments proof the possibility to decrease the health hazard of very hot beverages by lower brewing temperatures.
ARTICLE | doi:10.20944/preprints201908.0123.v1
Subject: Biology, Ecology Keywords: snake demography; moonlight; rain; temperature; climate change in Osa
Online: 11 August 2019 (05:35:15 CEST)
Introduction: studies in the last two decades have found declining snake populations in both temperate and tropical sites, including informal reports from Drake Bay, Costa Rica. Objective: to investigate if reports of decreasing snake populations in Drake Bay had a real basis, and if environmental factors, particularly temperature, rain and light, have played a role in that decrease. Methods: we worked at Drake Bay from 2012 through 2017 and made over 4000 h of transect counts. Using head flashlights we surveyed a transect covered by lowland tropical rainforest at an altitude of 12–38 m above sea level, near the Agujas River, mostly at 1930–2200 hours. We counted all the snakes that we could see along the transect. Results: snake counts increase from August to September and then decline rapidly. The May snakes/rainfall peaks coincide, but the second snake peak occurs one month before the rain peak; we counted more snakes in dry nights, with the exception of Imantodes cenchoa which was equally common despite rain conditions. We saw less Leptodeira septentrionalis on bright nights, but all other species were unaffected. Along the six years, the number of species with each diet type remained relatively constant, but the number of individuals declined sharply for those that feed on amphibians and reptiles. We report Rhadinella godmani, a highland species, at 12–38 m of altitude. Conclusion: night field counts of snakes in Drake Bay, Costa Rica, show a strong decline from 2012 through 2017.