Measurements of the Crystallization Rates of Amorphous Sucrose and Lactose Powders from Spray Drying

2007 ◽  
Vol 3 (4) ◽  
Author(s):  
Shuosi Wang ◽  
Tim Langrish
Keyword(s):  
Glass Transition ◽  
Relative Humidity ◽  
Room Temperature ◽  
Crystallization Process ◽  
Threshold Value ◽  
Molecular Structures ◽  
Effect Of Temperature ◽  
Effects Of Temperature ◽  
The Difference ◽  
Material Temperature

The effects of temperature, relative humidity and molecular structure on the crystallization process within amorphous solids have been explored. Lactose and sucrose were spray dried, and the products were exposed to different and relative humidities. To investigate the effect of temperature, experiments were conducted at both room temperature and 40oC. The rate of the crystallization was more than doubled for every increase of temperature by 10oC, up to three times for the case of lactose. These results are consistent with the picture of the process as an activated rate one. The effect of increasing relative humidity (RH) was observed to increase the rate of crystallization up to a threshold value, after which the rate was no longer affected by relative humidity. This threshold was found to be 51% for sucrose, at room temperature, which was lowered to 32% at 40oC. Lactose and sucrose, which have the same molecular weight of 342 g/mol but different molecular structures and thus glass transition temperatures, were exposed to similar conditions. The difference in molecular structures had little effect on the overall rate of the crystallization process for the same material temperatures, in contrast with the predictions of the Williams Landel Ferry equation, which suggests that the rate of crystallization is a function of the difference between the material temperature and the glass transition temperature.

The Effect of a Difference in Temperature and Humidity on certain Reactions of Female Aëdes aegypti (L.)

1952 ◽  
Vol 43 (1) ◽  
pp. 221-229 ◽  
Author(s):  
Alec H. Parker
Keyword(s):  
Relative Humidity ◽  
Aedes Aegypti ◽  
Room Temperature ◽  
Climatic Conditions ◽  
Effect Of Temperature ◽  
Full Description ◽  
Temperature And Humidity ◽  
Conditioning Effect ◽  
The Difference ◽  
C 50

Sir Rickard Christophers (1947) working at 25°C. and a relative humidity of 80–90 per cent. found female Aëdes aegypti to be attracted by a warm dry surface at 40°C., and to be unaffected by a moist surface at room temperature. The writer (1948), working at 28°C. and 50–70 per cent. R.H. (usually near 50 per cent.) found the opposite: a warm dry surface at temperatures from 36°C. to 40°C. had no effect, while a moist surface at room temperature exerted a quite definite attraction. The purpose of the present experiments was to test the hypothesis that the difference between the results obtained in these two investigations was due to the difference in the ambient temperature and humidity.Repetition of the relevant experiments at 25°C, 85–90 per cent. R.H., and 28°C, 50–55 per cent. R.H., gave results indicating that temperature and humidity difference operating at the time of the experiment could account for part but not all of the discrepancy. There are indications that the remainder may have been a result of the conditioning effect of temperature and humidity differences operating on the insect prior to the experiment.The results emphasise the need for a full description of the climatic conditions under which behaviour work of the type discussed is performed.

scholarly journals The Effect of Temperature and Humidity May Reduce the Growth Rate of the Coronavirus Disease 2019 Epidemic

2020 ◽  
Author(s):  
Lei Qin ◽  
Qiang Sun ◽  
Jiani Shao ◽  
Yang Chen ◽  
Xiaomei Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Relative Humidity ◽  
Effect Of Temperature ◽  
Average Temperature ◽  
Temperature And Humidity ◽  
Scatter Plots ◽  
Low Humidity ◽  
Average Relative Humidity ◽  
Effects Of Temperature ◽  
The Relationship

Abstract Background: The effects of temperature and humidity on the epidemic growth of coronavirus disease 2019 (COVID-19)remains unclear.Methods: Daily scatter plots between the epidemic growth rate (GR) and average temperature (AT) or average relative humidity (ARH) were presented with curve fitting through the “loess” method. The heterogeneity across days and provinces were calculated to assess the necessity of using a longitudinal model. Fixed effect models with polynomial terms were developed to quantify the relationship between variations in the GR and AT or ARH.Results: An increased AT dramatically reduced the GR when the AT was lower than −5°C, the GR was moderately reduced when the AT ranged from −5°C to 15°C, and the GR increased when the AT exceeded 15°C. An increasedARH increased theGR when the ARH was lower than 72% and reduced theGR when the ARH exceeded 72%.Conclusions: High temperatures and low humidity may reduce the GR of the COVID-19 epidemic. The temperature and humidity curves were not linearly associated with the COVID-19 GR.

APPLICATION OF REED-VIBRATION MECHANICAL SPECTROSCOPY FOR LIQUIDS IN STUDYING LIQUID CRYSTALLIZATION

2013 ◽  
Vol 27 (21) ◽  
pp. 1350080 ◽  
Author(s):  
HENG-WEI ZHOU ◽  
LI-NA WANG ◽  
LI-LI ZHANG ◽  
YI-NENG HUANG
Keyword(s):  
Glass Transition ◽  
Room Temperature ◽  
Crystallization Process ◽  
Volume Fraction ◽  
Supercooled Liquid ◽  
Avrami Exponent ◽  
Dimethyl Phthalate ◽  
Mechanical Spectroscopy ◽  
Crystal Volume ◽  
Complex Young’S Modulus

By using the reed-vibration mechanical spectroscopy for liquids (RMS-L), we measured the complex Young's modulus of dimethyl phthalate (DP) during a cooling and heating circulation starting from room temperature at about 2 KHz. The results show that there is no crystallization in the cooling supercooled liquid (CSL) of DP, but a crystallization process in the heating supercooled liquid (HSL) after the reverse glass transition. Based on the measured modulus, crystal volume fraction (v) during the HSL crystallization was calculated. Moreover, the Avrami exponent (n) was obtained according to the JJMA equation and v data. In view of n versus temperature and v, the nucleation dynamics was analyzed, and especially, there has already existed saturate nuclei in DP HSL before the crystallization. Furthermore, the authors inferred that the nuclei are induced by the random frozen stress in the glass, but there is no nucleus in CSL. The above results indicated that RMS-L might provide a new way to measure and analyze the crystallization of liquids.

scholarly journals Effects of Temperature, Relative Humidity, and Plant Age on Bacterial Disease of Onion Plants

2019 ◽  
Vol 20 (4) ◽  
pp. 200-206
Author(s):  
Kim E. Tho ◽  
Elizabeth Brisco-McCann ◽  
Prissana Wiriyajitsomboon ◽  
Mary K. Hausbeck
Keyword(s):  
Relative Humidity ◽  
Management Strategies ◽  
Bacterial Pathogen ◽  
Plant Age ◽  
Effect Of Temperature ◽  
Bacterial Disease ◽  
Disease Symptoms ◽  
Foliar Disease ◽  
Progress Curve ◽  
Effects Of Temperature

Foliar disease of onion in Michigan, caused by Pantoea agglomerans, Pantoea ananatis, or Enterobacter cowanii, has recently become a concern to producers. The objective of this study was to determine the effect of temperature, relative humidity (RH), and plant age in growth chamber and greenhouse experiments on onion plants inoculated with each pathogen. A significant level of disease resulted from each pathogen at 25 to 30°C, with strong positive associations detected using regression analysis between the area under the disease progress curve (AUDPC) and temperature. RH also significantly influenced symptom development. Foliar disease symptoms developed sooner and were more severe when RH was high (80 to 100%) but was limited at RH < 60%. Significant positive associations between RH and AUDPC, as described by linear regression, were also detected. When 6- to 14-week-old plants were inoculated with each bacterial pathogen, susceptibility increased significantly with age. These results provide insight into the epidemiology of P. agglomerans, P. ananatis, and E. cowanii bacterial pathogens of onions in Michigan and can assist in the development and timing of management strategies.

scholarly journals Effects of Climate on Incidence of Campylobacter spp. in Humans and Prevalence in Broiler Flocks in Denmark

2004 ◽  
Vol 70 (12) ◽  
pp. 7474-7480 ◽  
Author(s):  
Mary Evans Patrick ◽  
Lasse Engbo Christiansen ◽  
Michael Wainø ◽  
Steen Ethelberg ◽  
Henrik Madsen ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Linear Models ◽  
Public Health Problem ◽  
Effect Of Temperature ◽  
Maximum Temperature ◽  
Future Research ◽  
Combined Effects ◽  
Average Temperature ◽  
Effects Of Temperature ◽  
Single Predictor

ABSTRACT Campylobacter infections are increasing and pose a serious public health problem in Denmark. Infections in humans and broiler flocks show similar seasonality, suggesting that climate may play a role in infection. We examined the effects of temperature, precipitation, relative humidity, and hours of sunlight on Campylobacter incidence in humans and broiler flocks by using lag dependence functions, locally fitted linear models, and cross validation methods. For humans, the best model included average temperature and sunlight 4 weeks prior to infection; the maximum temperature lagged at 4 weeks was the best single predictor. For broilers, the average and maximum temperatures 3 weeks prior to slaughter gave the best estimate; the average temperature lagged at 3 weeks was the best single predictor. The combined effects of temperature and sunlight or the combined effects of temperature and relative humidity predicted the incidence in humans equally well. For broiler flock incidence these factors explained considerably less. Future research should focus on elements within the broiler environment that may be affected by climate, as well as the interaction of microclimatic factors on and around broiler farms. There is a need to quantify the contribution of broilers as a source of campylobacteriosis in humans and to further examine the effect of temperature on human incidence after this contribution is accounted for. Investigations should be conducted into food consumption and preparation practices and poultry sales that may vary by season.

scholarly journals Effects of Temperature and Moisture on Sporulation and Infection by Pseudoperonospora cubensis

Plant Disease ◽  
2017 ◽  
Vol 101 (4) ◽  
pp. 562-567 ◽  
Author(s):  
Shiling Sun ◽  
Sen Lian ◽  
Shulian Feng ◽  
Xiangli Dong ◽  
Caixian Wang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Downy Mildew ◽  
Weibull Model ◽  
Infection Process ◽  
Effect Of Temperature ◽  
Effective Control ◽  
Pseudoperonospora Cubensis ◽  
Cucumber Downy Mildew ◽  
Effects Of Temperature ◽  
Modified Weibull

Cucumber downy mildew, caused by Pseudoperonospora cubensis, is a worldwide disease that causes severe damage to cucumber production. The effects of temperature and moisture on sporulation and infection by P. cubensis were investigated by inoculating cucumber (‘85F12’) cotyledons with sporangia and examining the sporangia produced on the inoculated cotyledons under artificially controlled environments. The result showed that the temperature required for sporangium infection by P. cubensis and sporulation of the downy mildew lesions occurred at 5 to 30°C. The optimal temperature estimated by the fitted model was 18.8°C for sporangium infection and 16.2°C for downy mildew lesion sporulation. The pathogen formed plenty of sporangia when disease cotyledons were wetted or in the environment with relative humidity = 100%. The downy mildew lesions produced only a few sporangia when placed in the environment with relative humidity = 90%. The inoculated cotyledons, which incubated for 5 days at about 20°C in a dry greenhouse, began to form sporangia 4 h after being wetted when incubated in darkness. The quantity of sporangia produced on the downy mildew lesions increased with extension of incubating period (within 12 h), and the relationship between produced sporangia and the incubation period at 15, 20, and 25°C can be described by three exponential models. The observed minimum wetness durations (MWD) required for sporangia to complete the infection process and cause downy mildew were 12, 4, 2.5, 1, 1, and 6 h for 5, 10, 15, 20, 25, and 30°C, respectively. The effect of temperature and wetness duration on infection by sporangia of P. cubensis can be described by the modified Weibull model. The shortest MWD was 0.45 h, about 27 min, estimated by model. The experimental data and models will be helpful in the development of forecasting models and effective control systems for cucumber downy mildew.

scholarly journals Effects of Temperature on Colour of Selected Pig Organs in Silicone (S10) Plastination

2021 ◽  
Vol 5 (3) ◽  
pp. 324
Author(s):  
Tahmina Akhter ◽  
Mizanur Rahman Molla ◽  
Mahbub Alam ◽  
Tahmida Akhter ◽  
Farjana Akhond ◽  
...  
Keyword(s):  
Room Temperature ◽  
Colour Change ◽  
Resource Setting ◽  
Low Resource Setting ◽  
Temperature Group ◽  
Colour Changes ◽  
Background Temperature ◽  
Effects Of Temperature ◽  
The Difference ◽  
Medical University

Background: Temperature is one of the most important factors that are responsible for plastination procedure.Objective: The present study was designed to determine a suitable method of plastination of skeletal muscle in a low-resource setting in Bangladesh.Methods: This observational study was carried out in the Department of Anatomy, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh, between March 2015 and February 2016. Six whole pig kidneys (as firmer organ) and six whole pig lungs (as softer organs) were collected from a government authorized slaughterhouse in Dhaka city. Same numbers of organs were designated as ‘Cold Temperature Group’ and ‘Room Temperature Group’. We observed the change in colour at cold and room temperatures after different stages of plastination with a colour chart.Results: After fixation, both the brownish kidneys and reddish pink lungs turned brownish and darker. After dehydration, both the kidneys and lungs got paler. After forced impregnation, the colour turned much darker in both groups. The colour change continued towards a darker tone with time. The specific colour changes quantified into frequencies were very variable in both temperature groups.Conclusion: In observed colour changes, the difference was indeterminate.International Journal of Human and Health Sciences Vol. 05 No. 03 July’21 Page: 324-329

scholarly journals Influence of Temperature and Relative Humidity on Sporulation of Cercospora zeae-maydis and Expansion of Gray Leaf Spot Lesions on Maize Leaves

Plant Disease ◽  
2005 ◽  
Vol 89 (6) ◽  
pp. 624-630 ◽  
Author(s):  
P. A. Paul ◽  
G. P. Munkvold
Keyword(s):  
Relative Humidity ◽  
Leaf Spot ◽  
Quadratic Function ◽  
Leaf Tissue ◽  
Gray Leaf Spot ◽  
Quadratic Model ◽  
Effect Of Temperature ◽  
Cercospora Zeae Maydis ◽  
Maize Leaves ◽  
Effects Of Temperature

Controlled environment studies were conducted to determine the effects of temperature on the expansion of lesions of gray leaf spot, and the effects of temperature and relative humidity on the sporulation of Cercospora zeae-maydis on maize (Zea mays). For the lesion expansion experiment, potted maize plants were spray inoculated at growth stage V6, bagged, and incubated at 25 to 28°C and 100% relative humidity for 36 to 40 h. Symptomatic plants were transferred to growth chambers and exposed to constant temperatures of 25, 30, and 35°C. Lesion area (length by width) was measured at 4-day intervals for 17 days. For sporulation studies, lesions were excised from naturally infected maize leaves, measured, and incubated at constant temperature (20, 25, 30, or 35°C) and relative humidity (70, 80, 90, or 100%) for 72 h. Sporulation was estimated as the number of conidia per square centimeter of diseased leaf tissue. A quadratic function was used to model the relationship between log-transformed conidia per square centimeter at 100% relative humidity and temperature. Temperature had a significant effect on lesion expansion (P ≤ 0.05). At 25 and 30°C, the rate of lesion expansion was significantly higher than at 35°C (P ≤ 0.05). The largest lesions and the highest mean rate of lesion expansion were observed at 30°C; however, the mean lesion expansion rate at this temperature was not significantly different from that at 25°C. The interaction effect of temperature and relative humidity on the log of conidia per square centimeter of diseased tissue was significant (P ≤ 0.05). At 100% relative humidity, the effect of temperature on sporulation was significant (P ≤ 0.05), with maximum spore production occurring at 25 and 30°C. The quadratic model explained between 49 and 80% of the variation in the log of conidia per square centimeter at 100% with variation in temperature. These results suggest that the rapid increase in gray leaf spot severity generally observed during mid- and late summer may be due to favorable conditions for lesion expansion during this period. When relative humidity is >95%, expanding lesions may serve as a source of inoculum for secondary infections.

scholarly journals Effects of Temperature and Aeration on The Dissolved Oxygen (DO) Values in Freshwater Using Simple Water Bath Reactor: A Brief Report

2020 ◽  
Vol 3 (1) ◽  
pp. 25
Author(s):  
Febiyanto Febiyanto
Keyword(s):  
Dissolved Oxygen ◽  
Room Temperature ◽  
Temperature Treatment ◽  
Water Bath ◽  
Effect Of Temperature ◽  
Initial Concentration ◽  
Freshwater Sample ◽  
Effects Of Temperature ◽  
And Control

<em>This work investigated the effect of temperature and aeration treatments on the dissolved oxygen (DO) values in freshwater. The study was carried out using a simple water bath reactor in room temperature condition. Based on the results, freshwater sample without the aeration and temperature treatments (control) indicates a fluctuating profile on which the obtained values of DO were 4.21-4.98 mg/L at T<sub>average </sub>= 27.7 °C. However, the aeration treatment was slightly able to enhance the DO value up to 8.12 mg/L from the initial concentration of 3.88 mg/L at T<sub>average </sub>= 27.4 °C. Compared to the aeration treatment, the addition of temperature treatment has extremely increased the DO value up to 21 mg/L from 6.6 mg/L (T<sub>0 minutes</sub> = 27 °C)  for 20 minutes of DO observation (T<sub>20 minutes</sub> = 12.4 °C). Hence, this brief report suggests that the addition of temperature treatment gave a significant effect on the DO value in freshwater than the aeration treatment and control.</em>

Effects of Temperature Changes on the Mechanical and Ballistic Responses in Biathlon Shooting

2006 ◽  
Vol 74 (5) ◽  
pp. 1037-1041 ◽  
Author(s):  
Christelle Grebot ◽  
Alain Burtheret
Keyword(s):  
Room Temperature ◽  
Negative Temperature ◽  
Trigger Mechanism ◽  
Temperature Changes ◽  
Mechanical Responses ◽  
Cross Country Skiing ◽  
Mechanical Factors ◽  
Effects Of Temperature ◽  
Cross Country ◽  
The Difference

Background: Biathlon is a nordic sport that combines cross-country skiing with rifle marksmanship. It was reported that standing shooting was significantly affected because skiing exercise usually decreased the postural control of biathletes and increased the shooting time. Another hypothesis that may explain the decrease of one’s shooting accuracy after a cession of cross-country skiing could be linked with mechanical factors. The goal of the present study was to examine the influence of negative temperatures on the trigger mechanism and on the ballistic responses of the bullet. Method of approach: In order to determine the possible variations of the force required for triggering, five biathlon rifles were equipped with strain gauges fixed on the trigger. A thermostat vessel was used to control the temperature changes at room temperature (+20°C)(+68°F) until −20°C(−4°F). Concerning the ballistic measurements, eight series of five shots were performed at +20°C(+68°F), at −3°C(+26.6°F), at −10°C(+14°F), and at −20°C(−4°F). The shooting precision was assessed by determining the group diameter (GD) and the shooting score (Sc). Results: The results showed that from +20°C(+68°F) until −8°C(+17.6°F), the triggering force was equal to 5N(1.12lb), whereas at −20°C(−4°F), a triggering force of 8N(1.8lb) was required. The increase of the triggering force that was found under −8°C(+17.6°F) could be caused by the difference between the coefficients of expansion of the different materials constituting the trigger mechanism. Concerning the ballistic measurements, GD at room temperature was significantly lower (P<0.05) than −3°C(+26.6°F), −10°C(+14°F), and −20°C(−4°F). Furthermore, Sc was significantly better at +20°C(+68°F)(P<0.05) compared to −3°C(+26.6°F), −10°C(+14°F), and −20°C(−4°F) conditions. Conclusion: It can be supposed that the degradation of GD and Sc could be due to the formation of frost in the barrel and by the difference of the expansion coefficient of the bullet-barrel materials. Consequently, both mechanical responses could partly explain the shooting accuracy impairment observed in negative temperature shooting conditions.

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