Dehydration of prawns in tunnel dryers

This paper deals with the dehydration of prawns in a tunnel dryer. Conditions required to produce an end-product of desired colour, shape and texture as well as good reconstitution and organoleptic properties which are not obtained in the normal hot air drying, have been worked out. An initial temperature and relative humidity of 90°C. and 85%-90% respectively and an air velocity not more than 1 metre/second are the essential conditions required. Both temperature and relative humidity are to be reduced to 70°C and 40% respectively after about an hour's operation, till the drying is complete. Flavour of the reconstituted product is close to that of the fresh cooked prawns and the texture is judged to be soft. Drying time required to reduce the moisture content of fresh prawns to 15% level is about 7 hours compared to 6-7 hours in normal hot air drying and more than 36 hours in sun-drying.

Comparative feature on design, construction and installation of three different model of low cost solar tunnel dryers

The study was conducted in collaboration with the ECFC project of the FAO (BGD/97/017) in Cox's Bazar to develop a low cost solar tunnel dryer for the production of high quality marine dried fish. The study areas were Kutubdiapara, Maheshkhali and Shahparirdip under Cox's Bazar district. Three different models of low cost solar dryer were constructed with locally available materials such as bamboo, wood, bamboo mat, hemp, canvas, wire, nails, rope, tin, polythene and net. Size of the dryers were: 20x4x3 ft ; 30x3x3 ft and 65x3x3 ft with the costs of Tk. 3060, 3530, 9600 for dryer 1, 2 and 3, respectively having different models. The drying capacities were 50, 150, 500 kg for dryer 1, 2 and 3 respectively. The average temperature range inside the dryers were 29-43°C, 34-51°C and 37-57°C for dryer 1, 2 and 3 respectively as recorded at 8:30h to 16:30h. The relative humidity were in the ranges of 22-42%, 27-39% and 24-41 % in dryer 1, 2 and 3 respectively. The fish samples used were Bombay duck, Silver Jew fish and Ribbon fish. The total drying time was in the range of 30-42, 28-38 and 24-34 hours to reach the moisture content of 12.3-14.5, 11.8-14.3, and 11.6-14.1% in dryer 1, 2 and 3 respectively. Among these three fish samples the drying was faster in Silver Jew fish followed by Bombay duck and Ribbon fish in all the three dryer.

Drying kinetics of tomato by using electric resistance and heat pump dryers

Drying kinetics of tomato was studied by using heat pump dryer (HPD) and electric resistance dryers with parallel and crossed airflow. The performance of both systems was evaluated and compared and the influence of temperature, air velocity, and tomato type on the drying kinetics was analyzed. The use of HPD showed to be adequate in the drying process of tomatoes, mainly in relation to the conversion rate of electric energy into thermal energy. The heat pump effective coefficient of performance (COPHT,EF) was between 2.56 and 2.68, with an energy economy of about 40% when compared to the drying system with electric resistance. The Page model could be used to predict drying time of tomato and statistical analysis showed that the model parameters were mainly affected by drying temperature.

Calciners and dryers in mineral industries, Background information for proposed standards : environmental impact statement.

Mode of access: Internet.

How to repair washing machines, clothes dryers, dishwashers, refrigerators, vacuum cleaners, air conditioners, mixers, electric ranges, and other appliances.

Mode of access: Internet.

Washers and dryers.

"A Consumer publication from the General Services Administration."

An Automatic moisture control for continuous grain dryers /

Cover title.

The hygienic efficacy of different hand-drying methods : a review of the evidence

The transmission of bacteria is more likely to occur from wet skin than from dry skin; therefore, the proper drying of hands after washing should be an integral part of the hand hygiene process in health care. This article systematically reviews the research on the hygienic efficacy of different hand-drying methods. A literature search was conducted in April 2011 using the electronic databases PubMed, Scopus, and Web of Science. Search terms used were hand dryer and hand drying. The search was limited to articles published in English from January 1970 through March 2011. Twelve studies were included in the review. Hand-drying effectiveness includes the speed of drying, degree of dryness, effective removal of bacteria, and prevention of cross-contamination. This review found little agreement regarding the relative effectiveness of electric air dryers. However, most studies suggest that paper towels can dry hands efficiently, remove bacteria effectively, and cause less contamination of the washroom environment. From a hygiene viewpoint, paper towels are superior to electric air dryers. Paper towels should be recommended in locations where hygiene is paramount, such as hospitals and clinics.

Quality assessment of rotating and solar tunnel dried marine fish product

Studies were conducted to evaluate the quality aspects of marine dried fish i.e. silver jew fish (Johnius argentatus), Bombay duck (Harpodon nehereus) and ribbon fish (Trichiums haumela) products produced in rotating and solar tunnel dryers. On the basis of organoleptic characteristics such as colour, odour, texture, broken pieces, insect infestation and overall quality, four member panels of experts evaluated the quality of the dried products obtained from both rotating and solar tunnel dryers and all the products were found in acceptable quality. Reconstitutions properties of samples were in the range of 51.05 to 98.75% for the dried fish produced in rotating dryer, while 24.64 to 76.76% for dried fish produced in solar tunnel dryer. The highest reconstitution rate was found in dried silver jew fish and lowest in ribbon fish produced in rotating dryer. On the other hand, the highest reconstitution was observed in dried silver jew fish and lowest in dried Bombay duck produced in solar tunnel dryer. Proximate composition such as moisture, crude protein, lipid and ash content of the dried fish muscles produced in rotating dryer ranged from 16.36% to 19.1%, 62.35% to 67.37%, 6.37% to 10.75% and 7.00% to 8.05%, respectively and in solar tunnel dried fish products, they were in the range of 14.05% to 19.71%,57.64% to 69. 21%,6.92% to 15.40%and 7.69% to 8.80 %, respectively. The TVBN values of dried fish products obtained from rotating dryer were in the range of 15.02 to 19.05 mg/100g, while in solar tunnel dried fish products, the values were in the range of 15.46 to 19.21 mg/100g. The results of the studies indicated that dried fish produced from both rotating and solar tunnel drier were acceptable quality in terms of organoleptic and food quality aspects.

Organoleptic, biochemical and bacteriological aspects of the low cost tunnel dried fish products

Studies were conducted on the organoleptic, biochemical and bacteriological aspects of three dried fish products produced from two different model of low cost solar tunnel dryer. The overall quality of the products obtained from both dryers was excellent. Sixty minutes soaking showed the maximum water reconstitution of the products with values between 66.82 to 75.28% and 71.98 to 78.09% in dryer 1 & 2 respectively. The highest reconstitution was obtained from Silver Jew fish (75.28-78.09%) and lowest from Bombay duck (66.86-71.98%) from both dryers. The average moisture, protein, lipid and ash content of the dried products were 11.8-15.0%, 57.32-68.49%, 6.08-8.62% and 12.25-14.88% respectively in fish in dryer 1 and dryer 2. The TVB-N values were in the range of 24.3 to 30.9 in dryer 1 and 22.1 to 28.2 mg/100 g samples in dryer 2. The highest values were obtained from Bombay duck and lowest value in Silver Jew fish in both dryers. The peroxide values varied from 14.1 to 16.9% in dryer 1 and 13.3 to 16.4% in dryer 2. The highest peroxide value was obtained from Ribbon fish and lowest from Silver Jew fish. Total bacterial load varied in the range of 6.6x10⁴— 8.6x10⁴ CFU/g in dryer 1 and 2.54x10⁴ to 4.9x10⁴ CFU/g in dryer 2. The highest value was obtained from Ribbon fish and lowest from Silver Jew fish.

Production of quality dried small indigenous fish species products using low cost solar tunnel drier

A low cost solar drier was constructed using locally available materials. The size of the drier was 20x3.6x3 having drying capacity of 80 kg of SIS (w/w). Optimization of moisture content was observed for mola, dhela, chapila, chanda and puti at temperature ranges between 40-45°C and 50-55°C in solar tunnel drier. There was little or no change in moisture content at temperature below 40°C during the first 3 hours. Then the moisture content declined gradually with the increase of drying period. On the other hand, at temperature between 50-55°C, moisture content started to decline after 2 hours of drying. The moisture content of the sample reached at about 16% after 26 hours of sun drying at 40-45°C and 20 hours at 50-55°C. The optimum temperature for producing high quality dried products was 45-50°C in solar tunnel drier. The temperature and relative humidity outside and inside the dryers (with fish) at various locations were recorded from 8.00am to 4.00pm. The normal atmospheric ambient temperature was recorded in the range of 25-37°C from at 8:00am to 4:00pm. During the same period the atmospheric relative humidity recorded was in the range of 30-58%. On the other hand, the maximum temperature inside the dryers was recorded in the range of 28-65°C. The lowest temperature recorded was 28°C in the morning and at 13.00pm the highest temperature 65°C was recorded. The maximum relative humidity 58% found in the afternoon and minimum of 28% at noon. There was inverse relationship between temperature intensity of sunshine and humidity which decreased as sunshine increased. In total, it took around 26 hours of drying to reduce the moisture level to about 16%.

An aggregated fridge-freezer peak shaving and valley filling control strategy for enhanced grid operations

The need for fast response demand side participation (DSP) has never been greater due to increased wind power penetration. White domestic goods suppliers are currently developing a `smart' chip for a range of domestic appliances (e.g. refrigeration units, tumble dryers and storage heaters) to support the home as a DSP unit in future power systems. This paper presents an aggregated population-based model of a single compressor fridge-freezer. Two scenarios (i.e. energy efficiency class and size) for valley filling and peak shaving are examined to quantify and value DSP savings in 2020. The analysis shows potential peak reductions of 40 MW to 55 MW are achievable in the Single wholesale Electricity Market of Ireland (i.e. the test system), and valley demand increases of up to 30 MW. The study also shows the importance of the control strategy start time and the staggering of the devices to obtain the desired filling or shaving effect.

Differing methodologies to measure microbe dispersal during hand drying

Background: Having previously investigated the dispersal by different hand drying methods of a chemical indicator, fungi and bacteria on the hands of users, this new study assessed the potential for viral dispersal. Aims/Objectives: To determine differences between hand drying methods in their capacity to disperse viruses on the hands of users to other occupants of public washrooms and into the washroom environment. Method: A harmless virus was used to artificially contaminate the hands of participants prior to using three different hand drying devices (jet air dryer, warm air dryer, paper towel dispenser). Viral dispersal was assessed at different heights and distances from the hand drying devices and also at different times after use by means of an air sampler. Results: The jet air dryer was shown to produce significantly more dispersal of virus than the warm air dryer or paper towels. After use of the jet air dryer, high numbers of virus were detected at a range of heights with maximum numbers between 0.61 and 1.22 metres. Virus was also detected at distances of up to 3 metres from the jet air dryer and in the air for up to 15 minutes after its use. The warm air dryer and paper towel dispenser produced low or zero viral counts at different heights, different distances and times after use. Conclusion: Jet air dryers have a greater potential than other hand drying methods to disperse viruses on the hands and contaminate other occupants of a public washroom and the washroom environment.

The risk of viral dispersal and aerosolization by different hand-drying methods

Background World Health Organization hand hygiene guidelines state that if electric hand dryers are used, they should not aerosolize pathogens. Previous studies have investigated the dispersal by different hand-drying devices of chemical indicators, fungi and bacteria on the hands. This study assessed the aerosolization and dispersal of virus on the hands to determine any differences between hand-drying devices in their potential to contaminate other occupants of public washrooms and the washroom environment. Methods A suspension of MS2, an Escherichia coli bacteriophage virus, was used to artificially contaminate the hands of participants prior to using three different handdrying devices: jet air dryer, warm air dryer, paper towel dispenser. Virus was detected by plaque formation on agar plates layered with the host bacterium. Vertical dispersal of virus was assessed at a fixed distance (0.4 m) and over a range of different heights (0.0 – 1.8 m) from the floor. Horizontal dispersal was assessed at different distances of up to three metres from the hand-drying devices. Virus aerosolization and dispersal was also assessed at different times up to 15 minutes after use by means of air sampling at two distances (0.1 and 1.0 m) and at a distance behind and offset from each of the hand-drying devices. Results Over a range of heights, the jet air dryer was shown to produce over 60 times greater vertical dispersal of virus from the hands than a warm air dryer and over 1300 times greater than paper towels; the maximum being detected between 0.6 and 1.2 metres from the floor. Horizontal dispersal of virus by the jet air dryer was over 20 times greater than a warm air dryer and over 190 times greater than paper towels; virus being detected at distances of up to three metres. Air sampling at three different positions from the hand-drying devices 15 minutes after use showed that the jet air dryer produced over 50-times greater viral contamination of the air than a warm air dryer and over 110-times greater than paper towels. Conclusions Due to their high air speed, jet air dryers aerosolize and disperse more virus over a range of heights, greater distances, and for longer times than other hand drying devices. If hands are inadequately washed, they have a greater potential to contaminate other occupants of a public washroom and the washroom environment. Main messages: Jet air dryers with claimed air speeds of over 600 kph have a greater potential than warm air dryers or paper towels to aerosolize and disperse viruses on the hands of users. The choice of hand-drying device should be carefully considered. Jet air dryers may increase the risk of transmission of human viruses, such as norovirus, particularly if hand washing is inadequate.

Comparison of virus dispersal and aerosolization by different hand-drying devices

Background World Health Organization and EU hand hygiene guidelines state that if electric hand dryers are used, they should not aerosolize pathogens. Previous studies have investigated the dispersal by different hand-drying devices of chemical indicators, fungi and bacteria on the hands. This study assessed the aerosolization and dispersal of virus on the hands to determine any differences between hand-drying devices in their potential to contaminate other occupants of public washrooms and the washroom environment. Methods A suspension of MS2, an Escherichia coli bacteriophage virus, was used to artificially contaminate the hands of participants prior to using three different hand-drying devices: jet air dryer, warm air dryer, paper towel dispenser. Virus was detected by plaque formation on agar plates layered with the host bacterium. Vertical dispersal of virus was assessed at a fixed distance (0.4 m) and over a range of different heights (0.0 – 1.8 m) from the floor. Horizontal dispersal was assessed at different distances of up to three metres from the hand-drying devices. Virus aerosolization and dispersal was also assessed at different times up to 15 minutes after use by means of air sampling at two distances (0.1 and 1.0 m) and at a distance behind and offset from each of the hand-drying devices. Results Over a range of heights, the jet air dryer was shown to produce over 60 times greater vertical dispersal of virus from the hands than a warm air dryer and over 1300 times greater than paper towels; the maximum being detected between 0.6 and 1.2 metres from the floor. Horizontal dispersal of virus by the jet air dryer was over 20 times greater than a warm air dryer and over 190 times greater than paper towels; virus being detected at distances of up to three metres. Air sampling at three different positions from the hand-drying devices 15 minutes after use showed that the jet air dryer produced over 50-times greater viral contamination of the air than a warm air dryer and over 110-times greater than paper towels. Conclusions Due to their high air speed, jet air dryers aerosolize and disperse more virus over a range of heights, greater distances, and for longer times than other hand drying devices. If hands are inadequately washed, they have a greater potential to contaminate other occupants of a public washroom and the washroom environment. Main messages: Jet air dryers with claimed air speeds of over 600 kph have a greater potential than warm air dryers or paper towels to aerosolize and disperse viruses on the hands of users. The choice of hand-drying device should be carefully considered. Jet air dryers may increase the risk of transmission of human viruses, such as norovirus, particularly if hand washing is inadequate.