Search results

To study the drying effects of cobalt, manganous and mixed salts for their catalytic action in cross linking reactions occurring during the creation of an alkyd resin film.

The driers of Co‐octoate, Mn‐octoate, Mn‐octoate with an active organic ligand, and mixed drier containing the salts of Mn, Ca, and Zn were employed in the cross linking reactions of alkyls. The study verified the possibility of using manganese as an active cation in catalytic curing reactions. The course of the cross‐linking of alkyds was monitored on a model system of the reactions of drier with ethyl linoleate, using FTIR spectroscopy. Reaction‐rate constants corresponding to the first phase of cross linking were obtained. The driers under scrutiny were used to identify the time of the drying of alkyd resin modified with flax oil. The final phase of the cross linking reactions was monitored by means of measurement the hardness of the created alkyd film depending on time.

The driers under scrutiny were found to have catalytic effects in auto‐oxidation reactions. Very high efficiency was found with all of the driers. The highest efficiency was found with Co‐octoate resulting in the development of the highest hardness of coatings. Mn‐octoate and mixed driers show a steeper increase in film hardness than Co‐drier, yet the final films are suppler.

The driers studied can be conveniently used to accelerate creation of alkyd coatings modified with natural oils and designed for both industrial and decorative purposes.

The method of identifying the kinetic parameters of the cross‐linking reactions of alkyds is relatively new and facilitates the localisation of driers that are optimum for specific paints formulations. Of benefit is also the study of Mn‐driers that are more environmentally acceptable than Co‐driers.

Reports on a comprehensive study of the effects of different driers on film properties of alkyd resin. The driers selected for study were calcium naphthanate and the octoates of cobalt, manganese, lead and zirconium. The properties studied were hardness, adhesion, flexibility, film formation, skinning tendency, water and acid resistance, viscosity and drying time. Concludes that driers not only dry coatings (paints, varnishes, resigns, inks) but have significant effect on the film properties. Infers that a combination of manganese, lead and zirconium can be used as the most promising drier system for better coating properties.

The loss of an amount in excess of $100m cash deposit can be disruptive to the operations, definitely the liquidity of the hedge fund. Should a hedge fund liquidity position deteriorate, its compromised solvency could impact its vendors, most notably creditors and prime brokers. Large successful hedge funds do make basic mistakes. Lawyer Marc Dreier committed the criminal act of selling fraudulent promissory notes to hedge funds and others. Mr Drier’s success in selling fraudulent promissory notes was facilitated by his accomplices who posed as fake representatives of legitimate institutions. Drier and team presented bogus “audited financial statements” and forged developer’s signatures, and even went as far as using the unsuspecting institutions’ premises for meetings to meet potential notes buyers to further falsely legitimize the scheme. He had the notes buyers send their payments to his law firm account, to secure the money. His actions cost his victims, who include 13 hedge fund managers, other investors and entities, $400m in addition to his law firm’s employees who also suffered when his law firm was dissolved. For his actions, he was sentenced 20 years in federal prison for investment fraud. This study aims to direct hedge fund investors and other stakeholders to thoroughly vet the compliance function, especially controls on cash disbursements, even if the hedge fund is sizable (in excess of $1bn). Investors and even other stakeholders also should place a greater focus on what is usually overlooked issue; most notably the credit quality and authenticity of short-term investments bought by their hedge funds.

A thorough investigation of a fraud committed by a lawyer against a number of hedge funds. Several important lessons are identified to professionals who conduct due diligence on hedge funds.

The details of the case are very remarkable. This case directs investors’ attention to place greater efforts on certain aspects of operational risk and due diligence on not only hedge funds but also other investment managers. Normally investors conduct operational due diligence on the fund and its operations. Investors also vet fund external parties such as prime brokers, custodians, accountants and fund administrators. Yet, investors normally do not suspect the quality of short-term fund investments. In this case, the short-terms investments were the source of unforeseen yet substantial risk.

Stakeholders in hedge funds need to carefully investigate the issuer of and the quality of short-term investments that a hedge fund invests in. Future research can investigate the association of hedge fund manager failure with a liquidity position of the fund.

Investors must thoroughly the entirety of the fund including short-term securities.

Normally, it is the hedge funds that commit the fraud against investors. In this case, it is the multi-billion hedge funds run by sophisticated fund managers, who are the victims.

Although the element zirconium was not, until quite recently, associated with the bulk market for oil based and latex paints, there are four established areas of application for zirconium compounds:—

The paper aims to investigate the drying effect exhibited by pigments combined with a Co(II) salt of 2‐ethylhexanoic acid (Co(II)) in an alkyd resin modified by soya bean oil.

Paint hardening was studied by means of a method that follows the progress of alkyd film drying. Another important method was employed to monitor the gradually increasing hardness of the drying films. Hardness of thin films was measured by the Persos method. ZnO, ZnO nanoparticles, V₂O₅, ZnS and TiO₂ were used to study the effect of solid inorganic pigments on alkyd film drying. The pigment particles were characterised by scanning electron microscopy. The investigated pigments were combined with a constant amount of the Co(II) drier that acts in the system as a homogeneous catalyst, while the investigated pigments played the role of heterogeneous catalysts.

Using certain pigments as catalysts in drying, alkyd resins brings about new findings concerning the function of fillers and pigments in paint films. ZnO nanoparticles substantially accelerate film drying and moreover, the resulting films exhibit substantially higher hardness than films containing other inorganic pigments. To prepare films exhibiting higher hardness within a shorter time, one may also use ZnO microparticles or ZnS. TiO₂ and V₂O₅ were identified as pigments that either do not take part in the drying process or reduce the hardness of the resulting film.

The investigated catalytic system pigment/Co(II) drier can be advantageously used to accelerate the formation of alkyd paints modified by natural oils both for industrial and decorative purposes. It was established that hardness of paint films containing ZnO nanoparticles is twice as high as that of films containing only the Co(II) drier without any pigment. This finding makes new applications of alkyd paints possible in all instances where higher hardness is required.

Considering pigments as heterogeneous catalysts in systems producing films by the oxypolymerising mechanism is a new approach that gives rise to new and original solutions.

The complex cellular structure and chemical nature of fruit and vegetable tissues retard evaporation so that under no conditions of temperature and humidity does the rate of evaporation from them equal that from a free water surface. When conditions are such that surface evaporation from the tissues exceeds the rate of moisture diffusion to the surface, the surface becomes dry and hard and seals in the moisture. This condition, known as case‐hardening, is overcome by reducing the temperature of the air or by increasing the humidity. The maximum rate of drying, then, is attained by using the highest temperature which will not injure the product, the humidity being sufficient to prevent case‐hardening. In general practice the temperature of the air entering the drying chamber should not exceed 160° to 170° F. The humidity at the air‐outlet end of the drier should not greatly exceed 65 per cent. In driers employing recirculation the conditions of temperature and humidity may be largely controlled by varying the recirculation. The velocities of air flow which produce the most efficient results in the drying chamber depend upon several conditions. In general the rate of drying increases with the velocity of air movement. Low air velocities tend to bring about slow and uneven drying. Exceedingly high velocities may not be used profitably because a point is app ched at which the materials will be blown from the trays or at which the increased speed of drying will not offset the cost of operating a larger fan. Velocities of 600 to 800 feet per minute through the drying chamber are satisfactory in tunnel driers; lower velocities are permissible in compartment driers. The most practical means of removing moisture from the air, and at the same time conserving heat, is through the steady discharge of a portion of the air leaving the drying chamber. The rest dries efficiently when mixed with fresh air from the outside and reheated. All forced‐draught driers, therefore, should be provided with recirculation ducts connecting the air‐outlet end of the drying chamber with the heaters and with dampers controlling the air discharged, recirculated, and drawn from the outside. Dehydrated fruits and vegetables should have a uniform moisture content low enough to inhibit undesirable microbic and chemical changes within the food, and they should be free from any part of the life cycle of moths or other insects. The moisture content of dehydrated foods directly controls deterioration within the food, and the protection afforded by sulphuring or blanching will not prevent insufficiently dried products from soon becoming unfit for use. Dehydrated products having a low moisture content are not readily attacked by insects. In the long run the additional protection afforded by a low moisture content will more than make up to the producer the loss resulting from the longer drying time and greater weight shrinkage involved. To assure best keeping qualities the moisture content of fruits containing much sugar should not exceed 15 to 20 per cent., while that of other fruits and vegetables should not exceed 5 to 10 per cent., the preference in both cases being for the lower percentage. The texture, or feel, of products is a guide in determining when the proper stage of dryness has been reached. At a given moisture content products usually feel softer when hot than after they have been cooled, and often they feel softer after standing until the moisture has become evenly distributed throughout the pieces than when first cooled. A rough test for moisture in dried fruits is to take up a double handful, squeeze it tight into a ball, and release the pressure. If the fruit seems soft, mushy, or wet, and sticks together when the pressure is released, the moisture content is probably 25 per cent. or more. If the fruit is springy, and, when the pressure is released, separates in a few seconds to form pieces of approximately the original size and shape, the moisture content is usually about 20 to 25 per cent. If the fruit feels hard or horny and does not press together, falling apart promptly when the pressure is released, the moisture content is probably below 20 per cent. At the proper stage of dryness vegetables look thoroughly dry and are often hard or crisp. The Association of Official Agricultural Chemists has published a method for the determination of moisture in dried fruits. In using methods of this type, care must be taken to select a composite sample from different parts of the lot, so that it will be representative of the lot as a whole, and directions for preparing the sample must be carefully followed in order to obtain dependable results. Products are never uniformly dry when removed from the drier. Large pieces and pieces not as directly exposed to the currents of heated air as most of the material contain more moisture than the rest. Products should be stored in large bins until the moisture becomes evenly distributed. This period of curing will usually take several weeks. An alternative method is to place the dried product in large friction‐top cans for curing, thus insuring complete protection from contamination and insect infestation. Leafy vegetables, like spinach, must remain in the drier until the moisture content of the stems is very low. At this point the product is bulky and the leaves are brittle. For economy in packing and handling it is desirable to reduce the bulk by compression. For this purpose the leaves are exposed to currents of cool damp air until they have reabsorbed just enough moisture to make them slightly flexible. For convenience in handling and to facilitate the application of heat or fumigation, products should be packed in the room where they were cured and stored. Such a room should be strictly clean, dry, cool and well ventilated. The doors should fit tightly, and the windows should be covered with fine‐mesh screen to exclude dust and insects. An abundance of light assists in detecting the presence of insects and in keeping the room clean. The types of containers chosen for packing will depend largely upon the severity of the storage conditions, with particular reference to the humidity and to chances of insect infestation. An ideal container would be one which, while moderate in cost, would keep the product from absorbing moisture when exposed to the most severe conditions of storage and shipment, and would be impervious to insects. Sealed tin cans and glass jars give absolute protection against moisture absorption and insect infestation. Friction‐top cans are nearly as good. Tin containers, necessary for export shipments of dehydrated foods, are more expensive than paper containers. Wooden boxes are generally used for bulk goods. Liners of heavy paper or cardboard, and sometimes additional liners of waxed paper, are used. The use of moisture‐proof cellophane packages is increasing. All types of paper containers with which experiments have been made allow the absorption of moisture when the products are stored in damp places. Also paper containers do not give perfect protection against all insects, some of which can bore holes in paper, while the larval forms of others are so small that they can crawl through the slightest imperfections at the joints where the cartons are sealed. Most products, however, keep satisfactorily in double or triple moisture‐proof cellophane or waxed‐paper bags packed in waxed, moisture‐proof cartons, provided the initial moisture content is low and no live insects in any form enter the package. Packing in insect‐proof and moisture‐proof packages cannot be too greatly stressed.

Combination drier APB replaces Lead‐ or Barium‐based driers in alkyd paints. Combination drier APB shows, it is stated excellent drying performance also at lower temperatures and high humidity.

Fuel moisture is an important determinant of fire behaviour. Changes in climate will result in changes in fuel moisture and this will impact fire management by modifying the length and severity of the fire season and by changing opportunities for prescribed burning. This paper aims to examine the effect of climate on fuel moisture in Eucalypt forests.

A climate model is used to predict weather for five Australian cities from 1961 to 2100 under a high‐emissions scenario. Time series are extracted from the model and used as boundary conditions for a process‐based fuel moisture model. Fuel moisture predictions are used to examine two management variables: the number of days suitable for prescribed burning in spring, and the number of days when fire could burn in summer.

There were significantly more fire days in warmer‐drier years. The number of days with extremely low fuel moisture was also higher in warmer‐drier years. Variation in the number of burning days was narrower than for fire days but the number of burning days was lower in warmer‐drier years. The lower number of burning days in warm years was due to a higher rate of fuel drying in these years.

Analysis was limited to Australian locations. In future, the work should be expanded to include Eucalypt plantations on other continents.

The changes predicted will require changes to fire management practices, particularly the timing of prescribed burning.

This paper uses a new, physically based method to examine the effect of climate change on fuel moisture. It will be useful to fire managers seeking to adapt to a changing climate.

Drying of food for the purpose of preservation is by no means a modern idea. Although its origins are not clear it is known that for many thousands of years man has used sun‐dried fruits and vegetables to sustain him in off‐season periods. Sun‐dried dates, figs and apricots were used by the aboriginal inhabitants of the Mediterranean Basin and the Near East. A dried product prepared from potato was used by the inhabitants of the Andean Highlands up to three thousand years ago. Dried venison or buffalo meat, known as pemmican, was prepared by the American Indians before the arrival of Columbus. Drying of vegetables by artificial means was first reported in Britain in the Eighteenth century. Quantities of dried vegetables were used by the British troops in the Crimean War, by Union troops in the American Civil War and in many other early campaigns and expeditions. Dehydration of fruit by artificial means began towards the end of the nineteenth century in America.