Performance evaluation of two black nickel and two black chrome solar collectors

The test program was based on the evaluation of four unique solar collectors described below: (1) black nickel collector surface with a desiccant drying bed, (2) black nickel collector surface without a desiccant drying bed, (3) black chrome collector surface with a dessicant drying bed, and (4) black chrome collector surface without a desiccant drying bed. The test program included three distinct phases: Initial performance evaluation, natural environmental aging, and post-aging performance evaluation. Results of Phase III testing conclusively indicated a higher normalized efficiency for Black Chrome surfaces when compared to Black Nickel

Circular 99

We initiated this study to develop a single small scale boiling tank and test a drying technique on samples of velvet antler

Cigarette filter material and polypropylene fibres in concrete to control drying shrinkage

Due to a reduction in demand for cigarette filter material (North East UK), significant quantities have arisen that have little commercial value. The filter manufacturers have been looking for another outlet for their product and polypropylene fibre replacement in concrete was considered. The purpose of adding Type 1 polypropylene fibres (BS-EN14889) to concrete is to control plastic shrinkage and reduce bleeding. A paired comparison test was carried out to examine concrete cured under extreme conditions of heat and air flow. This micro climate would cause uneven drying due to surface evaporation and internal stresses within the concrete matrix and as a consequence of this instigate drying shrinkage cracking. Type 1 micro polypropylene fibres have known properties to control drying cracking and the performance of concrete with polypropylene fibres was compared against plain concrete and concrete with cigarette filter material. The findings showed that when cigarette filter material and Type 1 polypropylene fibres were compared together their performance was very similar and showed less drying shrinkage cracks than plain concrete

The effects of drying methods and storage conditions on pea seed (Pisum sativum L.) quality and the relationship between high temperature drying and maize seed (Zea mays L.) stress cracks : this thesis presented in fulfilment of the requirements for the degree of Master of Applied Science (Agricultural Engineering) in the Institute of Technology and Engineering, Massey University, New Zealand

High temperature and high relative humidity adversely affect the quality of seeds, and are features of tropical climate. Seed drying and storage are being used increasingly in developing countries to improve seed storage and quality. This study was undertaken to evaluate a range of seed drying methods and storage conditions with the view to selecting an appropriate method(s) for use in tropical countries. Pea (Pisum sativum L.) seeds at three initial seed moisture content (m.c.) of 23.8, 18.0 and 14.5% were dried to 10% seed m.c. before storage. The performances of four different drying methods: artificial dryer (Kiwi Mini) set at 30°C or 45°C, natural sun drying, and in-bin natural ventilation drying were evaluated. Natural sun drying, and in-bin natural ventilation drying were conducted from March to May, 1997, when mean temperature and relative humidity during sunny days were 17°C and 60% respectively. The dried seeds were stored under two conditions: open storage at 20.5°0 and 55% relative humidity (r.h.), and closed storage at 25°C and 90% r.h. for 20, 40, and 60 days. Time and energy consumed for drying by the different methods were determined to compare the drying efficiency when combined with quality of the seed. Deterioration of the seed due to storage conditions and drying methods used was determined by assessing their effects on seed germination, abnormal seedlings, dead seed, hollow heart percentages, and conductivity. Seed samples dried by the Kiwi Mini dryer set at 45°C took 7 hours and those set at 30°C took 17 hours. It took 54 hours with natural in-bin ventilation drying, while sun drying took 37 hours. However, energy consumed when drying seeds at 30°C was 17 kWh, which was more than twice that at 45°C. Seed germination was not significantly different between drying methods, but averaged only 75% because of sprouting damage of the crop prior to harvest. Germinations after open and closed storage for 20 days did not differ, although some differences appeared after 40 days of storage. However, open and closed storage for 60 days significantly reduced seed germination to 54 and 33% respectively. Because seeds are heat-sensitive, drying air temperature and drying rate are particularly important to avoid internal seed breakage, cracking and splitting, fungal growth, and loss of germination and vigour. Selected studies have shown that seed can be dried at high temperature for a short time, followed by tempering to re-distribute moisture and temperature inside the seed, thus reducing the percentage of cracking. Thus, a second experiment was conducted with maize (Zea mays L) to study the impact on seed viability of high temperature drying followed by tempering. Maize at 28.5% initial seed m.c. was dried at 60°C for short periods of 5, 10, 15, 20, or 25 minutes, followed by tempering for 45 minutes at either 30°C or 21°C. This cycle was repeated until maize seeds were dried to 13.0% m.c.. The percentage of cracked seeds, germination immediately after drying, and after an accelerated ageing test, did not differ between 30°C and 21°C tempering. Drying exposure times of up to 10 minutes per cycle at 60°C caused vertical cracks in up to 50% of seeds, but seed germination remained over 90% and seed vigour was also maintained. The percentage of seeds with stress cracks due to high temperature drying (5 - 25 minute cycles) at 60°C followed by tempering had polynomial relationships with seed germination and vigour. Seeds dried at the same temperature without tempering had their germination reduced from 99 to 20%

A study of the influence of physical parameters on the drying of porous media

An experimental setup is developed to observe the mass transfer that occurs in the drying of saturated porous media due to bulk flow of gas. The analysis and equations are developed in a one-dimensional perspective, and focus on the convection and evaporation that results. Humidity readings are monitored at various locations and used in the analysis of the results. These procedures are used in test cases for Steel spheres and Ceramic beads both 4.5 mm in diameter at.25 L/min,.5 L/min,.75 L/min and 1 L/min flow rates; Drying times and humidity plots versus time for both steel and ceramic are witnessed to be similar in nature. A correlation for the drying time is developed through use of Sherwood number, Reynolds number, and Schmidt number. This is achieved by using the non-dimensional quantities and acquiring a linear regression and equation. The coefficients and exponent values of the general equation for the Sherwood number are then solved

Factors affecting the activity of baker's compressed and active dry yeast : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Biotechnology at Massey University

Factors affecting the Activity of Baker's Compressed and Active Dry Yeast. Parameters important in the production of Baker's Yeast were correlated with the product's final activity. Activity was a measure of the gas evolved in a fermenting dough, expressed as mMCO2/hr/g yeast solids. The drying of Compressed Yeast to Active Dry Yeast was optimised in terms of the drying air. A tunnel tray drier was used to dry yeast to a 9% moisture content (dry weight). At 40°C. the optimum drying humidity was found to be 30-32% relative humidity. The leavening ability of yeast dried at 17% and 45% relative humidity decreased. A drying additive, 2% glyceryl monostearate, halved the drying time to 4 hours. Equations were developed to describe these observations as a function of relative humidity, drying time and additive concentration. The equilibrium relative humidity of stored dried yeast was found to be 32% at 20°C. Fermentation parameters were correlated with the activity of Compressed Yeast using an experimental design. Growth temperatures varied from 28°C. to 37°C., initial pH from 4 to 6, glucose concentrations from 0.5% to 3%, nitrogen concentrations from 0.3% to 1.2% and dissolved oxygen varied as either agitated or standing cultures. Factors significantly affecting cell yield and yeast activity were growth temperature, dissolved oxygen and glucose concentrations. Maximal yeast activity occurred at 0.5% glucose concentration, 28°C. and non-agitated conditions. A model was developed to describe yeast activity as a function of these variables. The observed optimal conditions for cell yield were similar to those for yeast activity except for the dissolved oxygen level. Maximum yeast activity of Compressed Yeast occurred in non-agitated fermentations, compared with cell yield which required agitated conditions to achieve the greatest cell yield. A rapid screening test for evaluating dried yeast was incorporated into the yeast activity analysis. This involved monitoring foam production during rehydration

PROSES PEMBUATAN MINUMAN HERBA ROSELA (Hibiscus sabdariffa \ud L.) :KAJIAN SUHU DAN LAMA PENGERINGAN

Plant has complex chemical components. People has been using herbal plant as medicine since long time ago. Rosela (Hibiscus sabdariffa L) one of herbal plant which is famous \ud talking because it’s merit and usefulness for health. The purpose of this research is to change rosellas’ petals into rosella herbal drink. Futhermore, this research has two \ud approaches to achieve the purpose. The first is knowing the effect of drying temperature and drying time length to the rosella herbal drink, then the second is knowing the \ud interaction between drying temperature and drying time length to the quality of rosella herbal drink. \ud This research was done at the Laboratorium of Farm Technology Muhammadiyah University of Malang on June until October 2007. The research used Randomized Complete Block \ud Design (RCBD) which was arranged factorially. Each of them repeated three times and obtained 12 combinations. Factor I : drying temperature S1 = 70OC, S2 = 80 OC, S3 = 90 \ud OC, and S4 = 100 OC. Factor II: drying time length, L1 = 120 minutes, L2 = 90 minutes, L3 = 60 minutes. Data collected was analyzed by using analysis of variance (ANOVA) technique, then continued by test of real differential DMRT 5%. \ud The research result indicated that there was interaction between drying temperature and drying time length to water rater, ash rate, nutrient C, total dissolved density, color \ud intensity, acidity (pH), anti-oxydant, and rendemen. The best treatment was S3L3 (drying temperature in 900C for 60 minutes). This treatment produced rosella tea with 11.0835% of water rate, 0.5540% of nutrient C, 5.2822 of ash rate, 2.7767 of acidity, 0.5467o Brix of dissolved density totally, 16.1667 of reddish level, 8 of yellowish level, 35.2333 of brightness, 13.1092% of rendemen, and 0.9067 of anti-oxydant. \ud In the organoleptic test, panelist prefered dried rosella which has 3.46 of color (quite interesting) and 3.26 of aroma (quite attracted). Moreover panelist prefered steeping rosella which has 3.13 of taste (quite good), 4.06 of color (interesting), and 2.33 of aroma (not interesting)

Correlating fissure occurrence to rice quality for various drying and tempering treatments

When a rice kernel fissures, it can break in subsequent food processing operations and lose its commercial value. Head rice yield (HRY) is a measure of the percent of kernels that remain whole (at least three-fourths of original length) after rice has been milled. Our experiment was designed to test the effect of a rapid state transition during drying and tempering processes using cultivars Bengal and Cypress. ‘Bengal’ is a medium-size kernel and ‘Cypress’ is a longsize, thinner grained cultivar. Immediately after drying, the rice samples were separated into four sub-samples and tempered for 0, 80, 160, or 240 minutes at the temperature of the drying air. Tempering is a process to allow kernel moisture content gradients to decrease, thereby reducing the stress within the kernel. From each sample, 400 kernels were randomly selected, visually observed, and the percentage of fissured kernels determined. Results showed that the percentage of fissured kernels generally decreased with tempering. However, some samples still showed many fissures even after extended tempering, yet had a high HRY. While HRY is currently the primary index of rice quality, it is known that fissured kernels can severely and detrimentally affect end-use processing operations such as cooking or puffing. Thus, the tempering duration required for preventing kernel fissuring might be longer than the tempering duration required for maintaining a high HRY

Shrinkage and Other Corn-Quality Changes From Drying at Commercial Elevators

Weight losses and corn-quality changes from drying and handling were measured at two modern country elevators. In addition to moisture losses, material handing losses averaged 0.88% of initial weight, with a range of 0.64% to 1.33% of initial weight. There was a fourfold increase in breakage susceptibility and a twofold increase in physical kernel damage after drying. Load-to-load variations in moisture content and test weight decreased after drying while load-to-laod variations in BCFM, breakage susceptibility and harvest damage increased after drying

The Effects of Freeze-Drying on the Strength Characteristics of Naturally Aged Book Papers

Libraries occasionally have water main breaks, fires and floods. These disasters cause considerable water damage to thousands of books. Books that are left wet on the shelves will grow mold. Books that are quickly frozen and eventually freeze-dried can be restored to the shelf in good condition. Several libraries have used freeze-drying for this purpose and have had great success. Freeze-drying is a process used to remove frozen liquid from a substance. The moist material is frozen and put in a vacuum. A high vacuum with some heat introduced will cause the frozen liquid to sublime. A dry-porous structure is left behind. There has been no test data found considering the effects of freeze-drying on the strength of papers. The purpose of this report is to examine this process. Eleven books up to 173 years old were wetted and freeze-dried. Some cockling of papers were observed. Strength properties of fold, tensile and zero span tensile essentially remained unchanged. Freeze-drying, in respect to the relatively small number of samples tested, does not have any detrimental effect on the strength of paper. Freeze-drying is recommended for restoration of water damaged books