Effects Of Inlet Air Temperature Research Articles

Effects of spray drying on the content of crystal proteins of Bacillus thuringiensis and the protection by organic and inorganic auxiliaries.

Spray drying is an important industrial method for the preparation of B. thuringiensis powder from fermentation liquor. The effect of spray drying on the crystal proteins, however, has not been reported in the literature so far. The present study systematically investigated the effect of inlet air temperature, outlet air temperature, atomizing air pressure and additives (including organic and inorganic auxiliaries) on the thermal destruction of crystal proteins of B. thuringiensis. The results indicated that the content of crystal proteins of B. thuringiensis powder decreased with increased inlet air temperature, outlet air temperature and atomising air pressure. The pseudo-z values for inlet air temperature, outlet air temperature and atomizing air pressure were 826.4℃, 204.0℃ and 4.74MPa, respectively. Among them, the outlet air temperature was a major parameter influencing the thermal destruction of crystal proteins, therefore, the decrease of the outlet air temperature was beneficial to increase the protein content in powder. Although the spray drying had an adverse effect on crystal proteins, the crystal protein content in spray-dried powder approached that in freeze-dried powder when the inlet air temperature of 165℃, outlet air temperature of 70℃ and atomizing air pressure of 0.15MPa were employed. The addition of some organic and inorganic auxiliaries to fermentation liquor can protect the crystal proteins from heat damage.

Optimization of spray drying process of buriti oil-loaded bilayer emulsions

Buriti oil is extracted from the fruits of a palm tree (Mauritia flexuosa L.) native to the Amazon rainforest, having one of the highest levels of β-carotene found in nature. The emulsification of buriti oil contributes to protecting the bioavailability of its bioactive compounds during processing. Drying oil-loaded emulsions is a way to produce microcapsules that have higher storage stability and expand the application possibilities of buriti oil. The objective of this work was to evaluate the impact of spray drying conditions on the microencapsulation of buriti oil, using response surface methodology. Bilayer emulsions were stabilized by whey protein isolate and high-methoxyl pectin and spray dried. The effects of inlet air temperature (154–196 °C) and feed flow rate (1.2–6.8 mL/min) on different properties of the microcapsules were evaluated. Higher air temperatures caused a positive effect on process yield but affected the color and encapsulation efficiency, while the increase in feed flow rate had a positive effect on the color of microcapsules. The higher drying rates negatively affected the microcapsules, resulting in larger and agglomerated particles, with the presence of holes in their surface. Surface models were obtained to predict color parameters of the microcapsules, which can be used as tools to quality control during processing. In general, the low drying rate resulted in microcapsules with suitable characteristics to ensure oil protection. The optimized spray drying process allows the production of buriti oil microcapsules with potential for application as natural pigments in the food industry.

A Study on the Conditions of Fog Generation and the Change Rule of Fog Zone Length in Air Intake Roadway

Fog in mine air intake roadways is a non-negligible disaster that seriously reduces the visibility of the roadway, affects vehicle transportation and the safe passage of personnel, and jeopardizes the safe production of the mine. This paper applies both field testing and numerical simulation to explore fog formation conditions and the effects of inlet air temperature and humidity on the fog zone length within the Wangjialing Mine’s air intake roadway in Shanxi, China. First, based on the consideration of the relationship between the moisture gain of surrounding rock and the temperature with humidity of the air flow, the fog generation and distribution law model of the air intake roadway was established. Based on this model, the critical inlet air temperature and the critical inlet air relative humidity for fogging in the Wangjialing Mine air intake roadway were determined. In addition, we found that the fogging point inside the roadway shifted forward continuously with the increase in inlet air temperature and inlet air relative humidity, and the length of the fog zone expands parabolically in response to these rising conditions.

Effect of Inlet Air Temperature and Quinoa Starch/Gum Arabic Ratio on Nanoencapsulation of Bioactive Compounds from Andean Potato Cultivars by Spray-Drying

Nanoencapsulation of native potato bioactive compounds by spray-drying improves their stability and bioavailability. The joint effect of the inlet temperature and the ratio of the encapsulant (quinoa starch/gum arabic) on the properties of the nanocapsules is unknown. The purpose of this study was to determine the best conditions for the nanoencapsulation of these compounds. The effects of two inlet temperatures (96 and 116 °C) and two ratios of the encapsulant (15 and 25% w/v) were evaluated using a factorial design during the spray-drying of native potato phenolic extracts. During the study, measurements of phenolic compounds, flavonoids, anthocyanins, antioxidant capacity, and various physical and structural properties were carried out. Higher inlet temperatures increased bioactive compounds and antioxidant capacity. However, a higher concentration of the encapsulant caused the dilution of polyphenols and anthocyanins. Instrumental analyses confirmed the effective encapsulation of the nuclei in the wall materials. Both factors, inlet temperature, and the encapsulant ratio, reduced the nanocapsules’ humidity and water activity. Finally, the ideal conditions for the nanoencapsulation of native potato bioactive compounds were determined to be an inlet temperature of 116 °C and an encapsulant ratio of 15% w/v. The nanocapsules obtained show potential for application in the food industry.

Investigation of a Solar-Powered Evaporative Cooling System under Tunisian Climate

The demand for cooling continues to increase in line with environmental changes and a greater desire for human comfort. In north Africa and middle eastern countries, and particularly in Tunisia, cooling constitutes a big problem as it is recommended for human and animal breeding. This study aimed to analyze the performance and suitability of an evaporative cooling system powered by solar energy and to assess the economic and environmental impact under Tunisian weather conditions. Numerical modeling and simulations were performed, revealing the effects of inlet air temperature and relative humidity on system performances. An experimental study based on the construction of an evaporative cooling prototype formed by environmentally friendly and locally available components was also performed. This study showed the dependence of the process performances on the humidity and temperature of the ambient air. The obtained results revealed that the efficiency of the evaporative cooler exceeds 90%, with maximum efficiency being reached at a high wet-bulb depression, while minimum efficiency was observed when the dry air has a high relative humidity and a low dry-bulb temperature. Experimental results showed that, for input temperatures ranges between 36 and 47 °C and relative air humidity between 15 and 50%, a direct humidifier produces air with a temperature range between 25 and 29 °C and humidity range between 55% and 85%. Thus, evaporative cooling is feasible and suitable under Tunisian climate conditions during the hot season.

Impact of spray drying conditions on the reconstitution, efficiency and flow properties of spray dried apple powder-optimization, sensorial and rheological assessment

Spray drying is a preferred choice for development of highly soluble, rapidly dispersible apple powder. However, adhesion during spray drying of syrups and juices is encountered which leads to product loss. The main solution to reduce adhesion is using drying aids. Besides, control of spray drying operating parameters (inlet air temperature and feed flow rate) also closely govern the powder yield, physical, functional and microstructural properties of spray dried fruit powder. Thus, the aim of the study was to evaluate the effect of inlet air temperature (IAT), carrier agent concentration (MD:GA), feed flow rate (FFR) & feed TSS (FTSS) on moisture content, hygroscopicity, dispersibility, water solubility index (WSI), bulk density (BD), porosity (Φ), flowability, lightness (L*) and radical scavenging activity (RSA). Design expert predicted IAT of 160 °C, MD and GA concentration of 14% and 6% respectively, FFR of 350 rpm & FTSS of 15oBrix as optimum condition for development of easily dispersible, highly soluble and least hygroscopic powder. The powder developed after following the optimized condition (SDAP) recorded moisture content as 2.91%, hygroscopicity as 25.29%, dispersibility as 92.50%, WSI as 94.17%, bulk density as 314.1 kg/m3, porosity as 57.19, flowability as 25.83°, L* value as 70.54 and RSA as 14.37. Among different powder reconstitution concentrations, 25% w/v concentration came out to be the best for reconstitution on the basis of sensory evaluation and rheological test. Frequency sweep test for all the reconstituted juice samples showed higher storage modulus than loss modulus for all the applied frequencies. The results of the study conferred that the developed powder could be used for commercial purpose.

Analysis of intake air temperature effect on performance of portable atmospheric water generation (PAWG) systems with heat sink angle orientation of 75o

The increasing demand for clean water and the diminishing supply of clean water sources can result in a clean water crisis. Air is a ubiquitous, inexpensive, and clean water source. Using Atmospheric Water Generators (AWG), the water contained in the air can be extracted. This study's objective was to determine the effect of inlet air temperature and air heater power variations on tool performance and PAWG condensate water production at a condenser angle of 75 degrees. The procedure utilized is experimental on three PAWG boxes. Each box has a distinct temperature at its entrance. The variation of inlet air temperature is accomplished by heating the air before it enters the box with an air heater; the applied power variations are 0.484 Watt, 0.964 Watt, and 1.702 Watt. The results demonstrated that variations in air heater power and inlet air temperature affected system performance and condensate water production. Maximum water discharge and PAWG performance were achieved when the air heating power was 0.48 watts and the water discharge was 1.166 milli liters per hour. At 0.0084 ml/h/W, the PSys system performance had the highest value. The variable air heating power of 0.946 Watt represents the utmost COP value of PAWG. This power variable has a high temperature difference and influences the COP value at high levels.

Experimental investigations of flow and thermal behavior of wall confluent jets as a heating device for large-space enclosures

The study aimed to explore the effects of inlet air temperature, outdoor air temperature, inlet bulk velocity, and the number of nozzles on wall confluent jets (WCJ) propagating along an external cold wall in a large space enclosure such as a greenhouse. A combination of experimental study and Response surface methodology has been used to predict the flow and thermal behavior of the WCJ for the studied cases. Box-Behnken design was used to determine the case matrix for four of the above-mentioned vital variables for non-isothermal cases. The experimental study employed constant current anemometers to measure the velocity and temperature of the WCJ. Results showed that the WCJ attached to the wall under both isothermal and non-isothermal conditions. This flow behavior suggests that the WCJ can be used to heat the external facades of large-space enclosures. All the stated variables were critical to the decay factor and decay rate of maximum velocity, albeit at varying levels. The velocity decayed faster with an increase in the inlet bulk velocity and outdoor air temperature. It also decayed faster as the number of nozzles and inlet air temperature decreased. The external wall surface temperature and the wall-heating effect increased as the momentum of the jet increased. The surface temperature on the external wall was most influenced by the inlet air temperature and least by the number of nozzles. Correlations of the second-order polynomial for the Response surface models that estimate the rate of velocity decay and temperature on the external wall were obtained.

Effect of Inlet Air Temperature on HCCI Engine Fuelled with Diesel- Eucalyptus Fuel Blends

Abstract: In this study, port injection single-cylinder HCCI engines were used to conduct an experimental investigation into the impact of diesel-Eucalyptus fuel blends on HCCI engine performance and exhaust pollutants. In the tests, eucalyptus and diesel were blended in a variety of volume ratios as test fuels, including 20% eucalyptus to 80% diesel (Eu20/D80), 40% eucalyptus to 60% diesel (Eu40/D60), 60% eucalyptus to 40% diesel (Eu60/D40), and 100% diesel. The tests were performed at a 1500 rpm engine speed with a 19-compression ratio at inlet air temperatures between 70° and 130°C. This study observed at the variations in brake thermal efficiency, exhaust gas temperature, and carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) emissions. According to test results, HCCI with diesel-Eucalyptus fuel blends increases brake thermal efficiency, exhaust gas temperature, decreases carbon monoxide, unburned hydrocarbons at inlet temperatures of 130°C, and decreases nitrogen oxides at inlet temperatures of 70°C. It was subsequently found that diesel-Eucalyptus fuel mixtures significantly affected the output and exhaust emissions of HCCI engines.

Thermo-economic assessment of bubbling fluidized bed paddy dryers

A thermo-economic assessment of bubbling fluidized bed paddy dryers under atmospheric conditions applying the response surface methodology (RSM) was carried out on three atmospheric bubbling fluidized bed dryers to investigate the effects of inlet air temperature, superficial air velocity and amount of paddy on exergy efficiency at the equilibrium moisture content (EMC). Furthermore, experiments were also performed in the designed cone-shaped dryer as per the experimental matrix obtained from the software design of experiments (DoE). Experimental results were utilized to develop the quadratic model and predict the exergy efficiency. The desirability approach was used to find the optimum value of 65 °C for inlet air temperature, 2.1 m/s for superficial air velocity and 3 kg of paddy with an overall desirability index of 0.996. The optimum values were experimentally tested and verified with the least error levels. The conical dryer with a larger degree of cone angle had a higher exergy efficiency. The maximal exergy efficiency of 0.41 was observed when a spiral was attached to the dryers. All dryers benefitted from a 28% increase in exergy efficiency due to the spiral. Furthermore, an economic analysis of the dryers was also carried out on the three dryers. A higher profit/year value of ($ 1171.87) was observed to be associated with dryers having a higher cone angle with a shorter payback period (0.43 years). As a result, a higher cone-angled dryer is proven to be the optimum option for drying paddy grains.

A measurement-based power consumption model of a server by considering inlet air temperature

The server power is critical not only for IT equipment power consumption, but also for non-IT power consumption in order to provide a suitable environment for IT equipment. The server power model is essential for thermal environment and energy efficiency. Due to the complication of the effects on power consumption of servers and few power models considering the inlet air temperature, this study firstly built an experimental setup to effectively facilitate the factor analysis. It then evaluated the effects of inlet air temperature and CPU utilization on server power consumption. During the experiment, the inlet air temperature was adjusted between 20 °C and 35 °C in 5 °C increments. Simultaneously, the SPECpower_ssj2008 was used to change the workload operations per second from 100% to idle, with a 10% interval. These measurements were also used in the server's various CPU power managements. When the inlet air temperature increases from 20 °C to 35 °C, the highest power increase was 17.60 W for Performance operating mode. Furthermore, in the DAPC and OS operating modes, the server power consumption has a piecewise linear relationship with its CPU temperature, and the function fits well when the CPU temperature is lower than 80 °C. For Performance and Workstation operating modes, the server power consumption is proportional to the temperature difference. The measurement-based correlation method employed by this paper can be used to investigate the power consumption model of other type or configured servers. If so, the adaptability of the model can be improved.

Spray‐process optimization for the encapsulation of probiotic Lactobacillus acidophilus ATCC 11975 in a ternary wall matrix

The inlet air temperature and feed flow rate of a spray drying process were optimized for encapsulation of Lactobacillus acidophilus ATCC 11975 using a ternary wall matrix of skim milk powder, maltodextrin, and cellulose acetate phthalate. The combined effect of inlet air temperature (140, 150, and 160℃) and feed flow rate (2.0, 2.5, and 3.0 ml/min) was studied on the encapsulation efficiency (EE), survival rate (SR), moisture content (MC), recovery yield (RY), and water activity (aw) by creating response surface plots in a full factorial design. A significant (p < .05) decrease in EE, SR, MC and aw, and increase in RY values of the powder were noticed by increasing the temperature and decreasing the feed rate. The optimum conditions to produce maximally viable probiotic powder were 145℃ and 2 ml/min. The shape of the particles was spherical. Thermal characterization revealed a better storage stability with a low inactivation rate. Practical applications Achieving a higher survival rate of probiotics to confer adequate health benefits to human gut is the prime concern of this research which was successfully achieved by optimizing the spray drying parameters. This manuscript details the potential application of a ternary wall matrix composite consisting of skim milk powder, maltodextrin, and cellulose acetate phthalate to successfully encapsulate the probiotic strain of Lactobacillus acidophilus, with improved encapsulation properties. The study will help towards formulating a novel dairy-based probiotic food with enhanced gut microbiota by generating the necessary background data required.

Numerical Assessment of Earth to Air Heat Exchanger with Variable Humidity Conditions in Greenhouses

Earth to air heat exchangers are widely utilized to cool or heat passive buildings for energy savings. They often need to deal with high humidity air conditions, especially in the greenhouse due to plant transpiration, and the condensation phenomenon is frequently observed during the cooling process. To evaluate the effect of humidity and condensation on thermal performance, a three dimensional computational fluid dynamic (3D-CFD) model was developed. The distribution of relative humidity in each pipe was investigated, and the impact of inlet air relative humidity on the integrated performance of the earth to air heat exchanger was discussed. The effects of inlet air temperature and volume flow rate were also analyzed. Moreover, the influence of the heat exchanger configurations on the performance of the air condensation was researched. The results indicated that condensation had few effects on the airflow distribution uniformity of the earth to air heat exchanger, while it acted observably on the thermal performance. In addition, humid air in a small diameter pipe tended to condense more easily. Humidity and condensation should be taken into consideration for the design of earth to air heat exchangers in greenhouses during engineering applications.

Influence of air temperature and Maltodextrin concentration on quality attributes of spray dried fermented beetroot juice powder

Present work was carried out to study the effect of inlet air temperature (140, 142, 144, 146 & 148 oC) and maltodextrin concentration (4, 5, 6, 7 and 8%) on the quality attributes such as moisture content, solubility, hygroscopicity, bulk density, betalain content and product recovery of the spray dried fermented beetroot juice powder. The results of experimental data show that increase in the inlet air temperature led to higher powder solubility and hygroscopicity. The moisture content, bulk density, betalain content and product recovery of the beetroot powder decreases with increase in the inlet air temperature. The increase in maltodextrin concentration caused a reduction in moisture content and betalain content. The optimized parameters for spray dried fermented beetroot juice powder have been obtained with inlet air temperature of 144 0C and maltodextrin of 6% at constant feed flow rate of 150 ml/h.

Numerical evaluation of the thermal performance of a near-surface earth-to-air heat exchanger with short-grass ground cover: A parametric study

Abstract High energy consumption and increasing energy cost have encouraged investment in energy efficiency. In hot areas, like the Middle East, the share of space cooling accounts for most of the total energy use in buildings. Earth-to-air heat exchangers represent an energy-efficient and environmentally friendly cooling technique. An earth-to-air heat exchanger buried near the ground surface with short-grass cover, which lowers the soil temperature by evapotranspiration, is an alternative to conventional deep buried types. In this study, a steady three-dimensional numerical model of this earth-to-air heat exchanger was developed by considering the conservation of mass, momentum, energy, and species. Soil temperature and moisture content measurements were used as boundary conditions for the model. In addition, the variations of soil temperature and thermal conductivity with depth were considered in the model. Numerical predictions of temperature matched experimental measurements within ±0.5 °C. Using the validated numerical model, the effect of inlet air temperature, airflow rate, tube length, material, wall thickness, and soil thermal conductivity on the earth-to-air heat exchanger thermal performance was investigated. Increasing the airflow rate and tube length resulted in an asymptotic increase and decrease in the earth-to-air heat exchanger outlet temperature, respectively. By increasing the tube wall thickness from 1 to 10 mm, the outlet temperature for an aluminum tube remained unchanged, while for PE and PVC tubes, the outlet temperature increased by about 1.1 and 2.2 °C, respectively. By increasing the soil thermal conductivity from 1 to 5 W m−1 K−1 the outlet temperature decreased by about 4.4 °C.

Preparation and optimization of multi-functional directly compressible excipient: an integrated approach of principal component analysis and design of experiments

Developing a new excipient and obtaining its market approval is an expensive, time-consuming, and complex process. The application of a multivariate analytical approach – principal component analysis (PCA) – in combination with the design of experiments (DoE) approach can make the process of developing co-processed excipient cost-effective and rapid. The present investigation was aimed to demonstrate the applicability of the DoE approach and PCA in developing a co-processed excipient by using the spray drying technique. The preliminary studies suggested a significant effect of inlet air temperature (X 1) and polymer ratio [chitosan chlorhydrate (CC): mannitol – X 2) on critical product characteristics so they were selected as independent variables in 32 full factorial design. The result of regression analysis suggested a significant effect of both independent variables on all response variables. The PCA of practically obtained value suggested a strong effect of all the selected response variables on the model. The prepared co-processed excipient had better tableting properties compared to the physical mixture of excipients and was able to accommodate more than 80% drug without compromising the flow property and compressibility. The present investigation successfully proved the applicability PCA and DoE approach as an effective and rapid tool for optimizing process parameters and formulation composition for preparing a directly compressible co-processed excipient.

Performance improvement of photovoltaic modules via temperature homogeneity improvement

Though the PV module performance can be enhanced by cooling, the associated temperature non-uniformity across the PV panel can deteriorate its efficiency. In this study, a significant effort is conducted for an air-cooling system that can control the temperature uniformity across the PV panel. The cooling of a rooftop PV module is enabled by the air-conditioning unit installed on the building’s roof. PV panel performance, with and without the cooling, is experimentally investigated for the uniform cold air duct. Experimental results showed that the cooled panel temperature is 6–12 °C lower than that of the uncooled one. However, even with the cooling, the temperature non-uniformity of 4–7 °C was noticed across the PV panel. To improve the temperature uniformity across the module, converging cold air ducts with different area ratios (AR) of 0.667 and 0.333 were designed and analyzed numerically. The effect of inlet air temperature (Tin-air = 18–23 °C) and inlet airflow velocity (U = 2–3 m/s) on panel temperature were also studied. The results suggested that the PV panel with CCD having an AR of 0.333 exhibited a temperature non-uniformity of 1.5–2.5 °C and demonstrated a 17–22% improvement in module efficiency under Tin-air = 18 °C and U = 3 m/s.

Influence of spray drying on bioactive compounds of blackberry pulp microencapsulated with arrowroot starch and gum arabic mixture

The objective of this research work was to obtain blackberry pulp in microencapsulated powder with a of arrowroot starch/gum arabic mixture by spray drying. Experimental design, with 11 runs, was performed to evaluate the effects of inlet air temperature (100–150 °C) and encapsulating agent concentration (1:0.5–1:2, blackberry pulp solids: arrowroot starch/gum arabic) on the functional properties of powders. The ascorbic acid content and luminosity of the powder increased with increasing encapsulating agent concentrations, whereas the b* values decreased. Increasing the inlet air temperature and decreasing the encapsulating agent concentration, the content of anthocyanins also increased. The powders were able to reduce Fe+3 and to trap free radicals, showing antioxidant property. The temperature of 143 °C and concentration of encapsulating agent 1:1.78 were the ideal conditions to have high content of ascorbic acid and good content of anthocyanins and antioxidant properties.

Optimization of the spray‐drying parameters for developing guava powder

AbstractSpray‐drying process for guava pulp was optimized by response surface methodology. The factors were inlet air temperature (130–170°C) and maltodextrin DE 10 content (60–75% wb pulp solids basis), while powder yield, moisture, ascorbic acid retention, rehydration, and hygroscopicity were the responses variables. Inlet air temperature caused a positive effect on powder yield and ascorbic acid retention, while moisture content, rehydration, and hygroscopicity were negatively affected by maltodextrin content. The optimal conditions for drying guava pulp were an inlet air temperature of 148°C and maltodextrin content of 75% wb pulp solids basis; these parameters led to 67.9% powder yield, 4.2% wb moisture content, 90% ascorbic acid retention, 60 s rehydration time, hygroscopicity 21.7 g of water/100 g of dry matter and 9.2 μm of particle mean diameter.Practical applicationNowadays an increase in the use of foods that are easy to make or ready for direct consumption has received a significant attention. Guava fruit has many health benefits potential, but it has short shelf life and seasonal crop. This research give the information about the effect of inlet air temperature and maltodextrin content on spray drying process and physicochemical properties of the developed guava powder. It is important for dehydrated pulp and juice producers to avoid production problems, such as stickiness and low yield.

Effect of spray drying temperature differences on the gross nutritional composition and solubility and sinkability of goat milk powder

Spray drying is a method of drying powder via microencapsulated from liquid rapidly with hot temperature in order to increase the shelf life. Hence, the objectives of the study are to investigate the effect of spray drying temperature on the nutritional composition and physical properties of dry milk powder of Saanen goat milk reared in Sandakan using maltodextrin as binder. The experiment tested the inlet air temperature variation from 140°C - 220°C with triplicates. The result was analyzed by a one-way analysis variance (ANOVA) using the Statistical Analysis System (SAS) version 9.4. The results showed that there are significant (p&lt;0.05) effects of inlet air temperature on dry milk powder in term of its protein content, fat content, moisture content and the sinkability of the milk powder. Among all of the treatments, the most sinkable temperature was at 140°C. Overall, the control powder, T0 = 180°C, however, is still preferable as nutritional value (for both protein and fat) shown to be higher in this powder and have acceptable moisture and physical properties. The finding of this study can be modified as for further investigation to improve the quality of milk powder in term of its nutritional value and physical properties.&#x0D; J. Bangladesh Agril. Univ. 17(2): 206–210, June 2019