Forced-air, vacuum, and hydro precooling of cauliflower (Brassica oleracea L. var. botrytis cv. Freemont): part I. determination of precooling parameters

The aim of the present study was to precool cauliflower using forced-air, vacuum and high and low flow hydro cooling methods. The weight of the precooled cauliflower heads (5000±5 g) was measured before they were placed in standard plastic crates. Cauliflower heads, whose initial temperature was 23.5 ± 0.5 ºC, were cooled until the temperature reached at 1 ºC. During the precooling process, time-dependent temperature and energy consumption were measured, and during vacuum precooling, the decreasing pressure values were recorded, and a curve of time-dependent pressure decrease (vacuum) was built. The most suitable cooling method to precool cauliflower in terms of cooling time and energy consumption was vacuum, followed by the high and low flow hydro and forced-air precooling methods, respectively. The highest weight loss was observed in the vacuum precooling method, followed by the forced-air method. However, there was an increase in the weight of the cauliflower heads in the high and low flow hydro precooling method. The best colour and hardness values were found in the vacuum precooling method. Among all methods tested, the most suitable method to precool cauliflower in terms of cooling and quality parameters was the vacuum precooling method.

Forced-air, vacuum, and hydro precooling of cauliflower (Brassica oleracea L. var. botrytis cv. Freemont): Part II. Determination of quality parameters during storage

Cauliflower heads, which were precooled using four different methods including vacuum, forced-air, and high and low flow hydro precooling, were stored under controlled atmosphere and room conditions. Controlled atmosphere conditions (CA) were as follows: 1°C temperature, 90 ± 5% relative humidity, and 0:21 [(%CO2:%O2) – (0:21) control] atmosphere composition. Room conditions (RC) were: 22±1°C temperature and 55-60% humidity. Various quality parameters of the cauliflower heads were assessed during storage (days 0, 7, 14, 21, 28, and 35) under controlled atmosphere and room conditions (days 0, 5, and 10). During storage, weight loss, deterioration rate, overall sensory quality score, hardness, and colour (L, a, b, C and α) were evaluated. In the present study, the strength and quality parameters of cauliflower under CA and RC conditions were obtained. Vacuum precooling was found to be most suitable method before cauliflower was submitted to cold storage and sent to market. Furthermore, the storage of cauliflower without precooling resulted in a significant decrease in quality parameters.

Particle size and cholesterol content of a mayonnaise formulated by OSA-modified potato starch

Egg yolk was partially replaced (0, 25, 50, 75, and 100%) with octenyl succinic anhydride (OSA)-modified potato starch in a reduced-fat mayonnaise formulation to curtail the problems associated with high cholesterol and induced allergic reactions. The physicochemical properties included parameters such as: pH, fat content, and emulsion stability of the formulations analyzed. The samples with 75% and 100% egg yolk substitute showed the maximum emulsion stability (>95% after two of months storage), and they were selected according to cholesterol content, particle size distributions, dynamic rheological properties, microstructure, and sensory characteristic. A significant reduction (84-97%) in the cholesterol content was observed in the selected samples. Particle size analysis showed that by increasing the amount of OSA starch, the oil droplets with the peak size of 70 µm engulfed by this compound became larger. The rheological tests elucidated that in the absence of egg yolk, OSA starch may not result in a final product with consistent texture and that the best ratio of the two emulsifiers (OSA starch/egg yolk) to produce stable reduced-fat, low cholesterol mayonnaise is 75/25. The microscopic images confirmed the formation of a stable cohesive layer of starch surrounding the oil droplets emulsified in the samples selected.

Microbiological and sensory evaluation of Jambu (Acmella oleracea L.) dried by cold air circulation

Abstract The aim of this study was to evaluate the microbiological and sensory quality of the Jambu (Acmella oleracea L.) in natura and dried by cold air, and the determination of its drying curve. The microbiological analysis were performed to Salmonella spp, the coagulase-positive Staphylococcus, and coliforms in the both Jambu samples, at 45 °C. Tacacá, the typical food dish of Pará state, Brazil, has showed good consumer global acceptance in the sensory evaluation of Jambu in natura (score of 8.00 ± 1.46) and dried (score of 8.67 ± 0.66). Both samples, Jambu in natura and dried by cold air, were by the current legislation regarding the microbiological aspects, this is the absence of Salmonella spp, coagulase-positive Staphylococcus <1×101 CFU/g, and coliforms <3 MPN/g, at 45 °C. Thus, considering sensory and health aspects, the commercialization of dried Jambu becomes viable, facilitating its transportation and handling, as well as for reducing its vegetable mass.

Open publishing: lessons from particle physics

Syksy Räsänen's presentation at Kirjastoverkkopäivät, Helsinki 21.10.2015.

Drying soybean seed using air ambient temperature at low relative humidity

Under subtropical and tropical environments soybean seed (Glycine max (L.) Merrill) are harvested early to avoid deterioration from weathering. Careful after-harvest drying is required and is an important step in maintaining the physiological quality of the seed. Soybean seed should be harvested when the moisture content is in a range of 16-20%. Traditional drying utilizes a high temperature air stream passed through the seed mass without dehumidification. The drying time is long because the system is inefficient and the high temperature increases the risk of thermal damage to the seed. New technology identified as heat pipe technology (HPT) is available and has the unique feature of removing the moisture from the air stream before it is passed through the seed mass at the same environmental temperature. Two studies were conducted to evaluate the performance of HPT for dry soybean seed. In the first study the seeds were dried from 17.5 to 11.1% in 2 hours and 29 minutes and in the second sudy the seeds were dried from 22.6 to 11.9% in 16 hours and 32 minutes. This drying process caused no reduction in seed quality as measured by the standard germination, tetrazolium-viability, accelerated aging and seedling vigor classification tests. The only parameter that indicated a slight seed quality reduction was tetrazolium vigor in the second study. It was concluded that the HPT system is a promising technology for drying soybean seed when efficiency and maintenance of physiological quality are desired.

Drying peanut seed using air ambient temperature at low relative humidity

The moisture content of peanut kernel (Arachis hypogaea L.) at digging ranges from 30 to 50% on a wet basis (w.b.). The seed moisture content must be reduced to 10.5% or below before seeds can be graded and marketed. After digging, peanuts are cured on a window sill for two to five days then mechanically separated from the vine. Heated air is used to further dry the peanuts from approximately 18 to 10% moisture content w.b. Drying is required to maintain peanut seed and grain quality. Traditional dryers pass a high temperature and high humidity air stream through the seed mass. The drying time is long because the system is inefficient and the high temperature increases the risk of thermal damage to the kernels. New technology identified as heat pipe technology (HPT) is available and has the unique feature of removing the moisture from the air stream before it is heated and passed through the seed. A study was conducted to evaluate the performance of the HPT system in drying peanut seed. The seeds inside the shells were dried from 17.4 to 7.3% in 14 hours and 11 minutes, with a rate of moisture removal of 0.71% mc per hour. This drying process caused no reduction in seed quality as measured by the standard germination, accelerated ageing and field emergence tests. It was concluded that the HPT system is a promising technology for drying peanut seed when efficiency and maintenance of physiological quality are desired.

Air-Sea Battle -konsepti John Wardenin Enemy as a System -teorian näkökulmasta

Tutkielman tavoitteena oli analysoida Air-Sea Battle -konseptia ja sen lähtökohtana ollutta viholliskuvaa John Wardenin Enemy as a System -teorian näkökulmasta julkisten asiakirjojen, raporttien ja artikkeleiden avulla. Tutkimusmenetelmänä on käytetty teoriaohjaavaa sisällönanalyysia. Tutkimusongelmaksi muodostui: ”Miten Air-Sea Battle -konsepti näyttäytyy Wardenin Enemy as a System -teorian näkökulmasta?” Tutkimuskysymyksien avulla pyrittiin lisäksi löytämään konseptin kehittämiseen johtaneita tekijöitä suurstrategisella tasolla, arvioimaan konseptin mukaista aseellisen voiman käyttöä sekä analysoimaan konseptia suhteessa Wardenin näkemyksiin sotilasstrategiasta. Wardenin Enemy as a System -teoria on esitelty tutkielman alkupuolella hyödyntäen alkuperäistekstejä, aiheesta kirjoitettuja tutkimuksia ja artikkeleita sekä sotataidollista kirjallisuutta. Air-Sea Battle -konseptia käsittelevän luvun aineisto on luokiteltu Wardenin neljän strategisen kysymyksen teemojen, eli tavoitteen, vaikuttamisen kohteiden, keinojen ja irtautumisen, mukaisesti. Tärkeimmät lähteet varsinaisen Air-Sea Battle -asiakirjan lisäksi olivat Yhdysvaltojen turvallisuus- ja sotilasstrategiaa määrittelevät dokumentit, tutkimuslaitosten julkaisemat raportit sekä aikakauslehtiartikkelit. Aineiston perusteella Yhdysvallat näkee tiettyjen valtioiden, kuten Kiinan, kehittyvät niin kutsutut anti-access/area denial -suorituskyvyt uhkana alueelliselle tasapainolle ja heidän kyvylleen ylläpitää sotilaallista läsnäoloa strategisesti merkittävillä alueilla. Air-Sea le -konseptin tavoitteena on määritellä ja kehittää suorituskyvyt, operatiiviset suunnitelmat ja toimintamallit, joiden mukaan toimivalla joukolla kyetään luomaan riittävä pelotevaikutus konfliktin ehkäisemiseksi tai säilyttämään toiminnanvapaus alueella sen muodostuessa.

Air defence in Northern Europe

Finnish Defence Studies is published under the auspices of the National Defence College, and the contributions reflect the fields of research and teaching of the College. Finnish Defence Studies will occasionally feature documentation on Finnish Security Policy. Views expressed are those of the authors and do not necessarily imply endorsement by the National Defence College.

Dynamic modeling and simulation of the airflow cleaning device

The objective of the work is to study the flow behavior and to support the design of air cleaner by dynamic simulation.In a paper printing industry, it is necessary to monitor the quality of paper when the paper is being produced. During the production, the quality of the paper can be monitored by camera. Therefore, it is necessary to keep the camera lens clean as wood particles may fall from the paper and lie on the camera lens. In this work, the behavior of the air flow and effect of the airflow on the particles at different inlet angles are simulated. Geometries of a different inlet angles of single-channel and double-channel case were constructed using ANSYS CFD Software. All the simulations were performed in ANSYS Fluent. The simulation results of single-channel and double-channel case revealed significant differences in the behavior of the flow and the particle velocity. The main conclusion from this work are in following. 1) For the single channel case the best angle was 0 degree because in that case, the air flow can keep 60% of the particles away from the lens which would otherwise stay on lens. 2) For the double channel case, the best solution was found when the angle of the first inlet was 0 degree and the angle of second inlet was 45 degree . In that case, the airflow can keep 91% of particles away from the lens which would otherwise stay on lens.

Natural freeze crystallization : purification of aqueous Na2SO4 solutions with cold air

The aim of this thesis was to examine efficiency of freeze crystallization and eutectic freeze crystallization in purification of wastewater by imitating natural freezing. In addition, a mathematic model based on heat transfer to determine ice thickness and ice growth rate was examined. Also, the amount of sodium sulfate crystallized at the eutectic point was under investigation. In literature part, advantages and applications of the freeze crystallization are discussed, and possibility to apply it in Northern hemisphere winter weather conditions is under study. Furthermore, main sources of sodium sulfate from Finnish industries are described. The experiments were carried out in modified chest freezer, where a fan was placed in order to obtain laminar air flow inside. Picolog PT-104 data logger was used to monitor temperature changes in the salt-water solution, and constant temperature was maintained in the crystallizer with Lauda RP 850 thermostat. The impurity of formed ice layer was determined by weighing ice samples after experiment and again after 24 hours drying to full dryness in oven. Volume of salt-water solution was also measured after experiment. The highest purity of formed ice layer was obtained with small temperature difference and with long freezing time. On the other hand, the amount of crystallized sodium sulfate was its greatest with long freezing time and higher temperature difference. The results obtained by the mathematic model and empirical results did not differ significantly in most of the experiments. However, the difference increased when salt-water mixture reached its eutectic point, leading to simultaneous ice and salt crystallization. Eutectic point was reached only with the highest salt concentration with one exception. In these cases, calculated values were in many cases greater than the experimental ones. In winter weather conditions freeze crystallization is cost-effective wastewater treatment method and rather simple. Nonetheless, the efficiency and separation rate are strongly depended on ambient temperature and its changes

Stochastic particle models: mean reversion and burgers dynamics. An application to commodity markets

The aim of this study is to propose a stochastic model for commodity markets linked with the Burgers equation from fluid dynamics. We construct a stochastic particles method for commodity markets, in which particles represent market participants. A discontinuity in the model is included through an interacting kernel equal to the Heaviside function and its link with the Burgers equation is given. The Burgers equation and the connection of this model with stochastic differential equations are also studied. Further, based on the law of large numbers, we prove the convergence, for large N, of a system of stochastic differential equations describing the evolution of the prices of N traders to a deterministic partial differential equation of Burgers type. Numerical experiments highlight the success of the new proposal in modeling some commodity markets, and this is confirmed by the ability of the model to reproduce price spikes when their effects occur in a sufficiently long period of time.

Sähkösuodattimen mahdollisuudet sisäilman parantajana

Diplomityön tavoitteena oli selvittää, kuinka sähkösuodattimella voidaan vaikuttaa sisäilman laatuun ja kuinka kilpailukykyinen vaihtoehto pienkiinteistöissä sähkösuodatin on perinteisiin kuitusuodattimiin verrattuna. Teoriaosassa tarkasteltiin, kuinka ilman hengitettävät hiukkaset muodostuvat ja miten ne vaikuttavat sisäilman laatuun sekä ihmisten terveyteen. Tarkasteltiin hiukkasten koon, lukumäärän, massan ja pinta-alan yhteyksiä niiden terveysvaikutuksiin. Ultrapienet hiukkaset ovat terveydelle haitallisimpia, koska hiukkasten lukumäärä ja pinta-ala lisäävät terveyshaittoja enemmän kuin hiukkasten massa. Tutkittiin pienkiinteistöjen ilmanvaihtoratkaisuja ja erilaisia tuloilmanpuhdistus-menetelmiä. Soveltavassa osassa tarkasteltiin sähkösuodattimen toimintaa ja sen mahdollisuuksia sisäilman parantajana verrattuna perinteisiin kuitusuodattimiin. Tehtiin sähkösuodattimen ja kuitusuodattimen välinen elinkaarikustannusvertailu keskisuurelle omakotitalolle. Kirjallisuuden ja tutkimushavaintojen perusteella sähkösuodattimen suurin etu muihin suodattimiin verrattuna on sen kyky poistaa kaiken kokoisia, myös ultrapieniä, hengitettäviä hiukkasia ja siten tehokkaasti vähentää hengitettävien hiukkasten lukumäärää ja pinta-alaa. Tällä voi olla vaikutusta yleisten terveyshaittojen ja ympäristöherkkyyden ennaltaehkäisemisessä. Ympäristöherkkyyteen sairastuneiden oireiluun sähkösuodatin voi tuottaa helpotusta kotioloissa ja siirrettävän ilmanpuhdistimen avulla myös työpaikoilla. Elinkaarikustannusvertailun perusteella selvisi, että sähkösuodatin on kalliimmasta hinnastaan huolimatta kokonaiskustannuksiltaan selvästi edullisempi vaihtoehto kuin kuitusuodattimet. Sähkösuodattimen haasteena on uuden teknologian lanseeraaminen pientalorakentamiseen. Pienrakennusten tuloilman puhdistusmenetelmien kehittämisellä olisi mahdollista parantaa suomalaisten elämänlaatua ja saavuttaa merkittäviä säästöjä terveydenhoitokuluissa.