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That ice‐creams prepared with dirty materials and under dirty conditions will themselves be dirty is a proposition which, to the merely ordinary mind, appears to be sufficiently obvious without the institution of a series of elaborate and highly “scientific” experiments to attempt to prove it. But, to the mind of the bacteriological medicine‐man, it is by microbic culture alone that anything that is dirty can be scientifically proved to be so. Not long ago, it having been observed that the itinerant vendor of ice‐creams was in the habit of rinsing his glasses, and, some say, of washing himself—although this is doubtful—in a pail of water attached to his barrow, samples of the liquor contained by such pails were duly obtained, and were solemnly submitted to a well‐known bacteriologist for bacteriological examination. After the interval necessary for the carrying out of the bacterial rites required, the eminent expert's report was published, and it may be admitted that after a cautious study of the same the conclusion seems justifiable that the pail waters were dirty, although it may well be doubted that an allegation to this effect, based on the report, would have stood the test of cross‐examination. It is true that our old and valued friend the Bacillus coli communis was reported as present, but his reputation as an awful example and as a producer of evil has been so much damaged that no one but a dangerous bacteriologist would think of hanging a dog—or even an ice‐cream vendor—on the evidence afforded by his presence. A further illustration of bacteriological trop de zèle is afforded by the recent prosecutions of some vendors of ice‐cream, whose commodities were reported to contain “millions of microbes,” including, of course, the in‐evitable and ubiquitous Bacillus coli very “communis.” To institute a prosecution under the Sale of Food and Drugs Act upon the evidence yielded by a bacteriological examination of ice‐cream is a proceeding which is foredoomed, and rightly foredoomed, to failure. The only conceivable ground upon which such a prosecution could be undertaken is the allegation that the “millions of microbes ” make the ice‐cream injurious to health. Inas‐much as not one of these millions can be proved beyond the possibility of doubt to be injurious, in the present state of knowledge; and as millions of microbes exist in everything everywhere, the breakdown of such a case must be a foregone conclusion. Moreover, a glance at the Act will show that, under existing circumstances at any rate, samples cannot be submitted to public analysts for bacteriological examination—with which, in fact, the Act has nothing to do—even if such examinations yielded results upon which it would be possible to found action. In order to prevent the sale of foul and unwholesome or actual disease‐creating ice‐cream, the proper course is to control the premises where such articles are prepared; while, at the same time, the sale of such materials should also be checked by the methods employed under the Public Health Act in dealing with decomposed and polluted articles of food. In this, no doubt, the aid of the public analyst may sometimes be sought as one of the scientific advisers of the authority taking action, but not officially in his capacity as public analyst under the Adulteration Act. And in those cases in which such advice is sought it may be hoped that it will be based, as indeed it can be based, upon something more practical, tangible and certain than the nebulous results of a bacteriological test.

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder metallurgy and composite material processing are briefly discussed. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE researchers/users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for 1994‐1996, where 1,370 references are listed. This bibliography is an updating of the paper written by Brannberg and Mackerle which has been published in Engineering Computations, Vol. 11 No. 5, 1994, pp. 413‐55.

OWING to the comparatively early date in the year of the Library Association Conference, this number of THE LIBRARY WORLD is published so that it may be in the hands of our readers before it begins. The official programme is not in the hands of members at the time we write, but the circumstances are such this year that delay has been inevitable. We have dwelt already on the good fortune we enjoy in going to the beautiful West‐Country Spa. At this time of year it is at its best, and, if the weather is more genial than this weather‐chequered year gives us reason to expect, the Conference should be memorable on that account alone. The Conference has always been the focus of library friendships, and this idea, now that the Association is so large, should be developed. To be a member is to be one of a freemasonry of librarians, pledged to help and forward the work of one another. It is not in the conference rooms alone, where we listen, not always completely awake, to papers not always eloquent or cleverly read, that we gain most, although no one would discount these; it is in the hotels and boarding houses and restaurants, over dinner tables and in the easy chairs of the lounges, that we draw out really useful business information. In short, shop is the subject‐matter of conference conversation, and only misanthropic curmudgeons think otherwise.

In his book on Animal Chemistry Liebig wrote as follows:—

The outbreak of typhoid fever which had been traced to a “carrier” of the fever germs may be given as a reason for the following note on the regulations relating to the manufacture of ice cream. This brief re‐statement of the regulations will serve to indicate the nature of the control exercised by the health authorities over a widely spread trade. It need hardly be pointed out that cream in the usually accepted sense of that term or its substitute containing a certain proportion of milk powder or skim milk is peculiarly liable to act as an agent in the dissemination of certain types of disease. “New regulations, the “Ice Cream (Heat Treatment) Regulations, 1946,” at present in draft, but operative from May 1st, 1947, deal with the sterilisation of the raw material and the retail sale in the finished and frozen state. Registration of premises, inspection by the local authority, combined with the goodwill of the trade, are obvious safeguards. The term “ice cream” possibly suggests to the average consumer a frozen mixture of cream—as that word is usually understood to mean—flavoured with the fresh juice or fresh‐fruit pulp of the name fruit. Such a mixture, if made from wholesome materials under hygienic conditions, would be a good, palatable luxury, and from the nature of the case seasonal. Most of us at some December midnight have had something called strawberry ice. The name stands, but the composition is rather a matter for speculation by the uninitiated. The term “cream” has been for many years applied to substances which though wholesome in themselves are not cream—vegetable fats, milk powder and the like—but they form the basis, so to speak, either in whole or in part of ice cream. There is in fact no official standard to define what is meant by ice cream, and the definition which we have ventured to offer must obviously be extended to apply to a large number of substances that do not of necessity consist either partly, still less wholly, of cream or of any substance whose origin is to be found in fruit of any kind. Ice cream, in fact, is a substance whose composition it seems may vary within wide and undefined limits. Thus the Ice Cream (Prohibition of the Manufacture and Sales) Order, 1942, says “‘Ice cream’ includes water ices.” The Ice Cream Transport Order (No. 305, March 22nd, 1945), prohibiting the export of ice cream to Great Britain from Northern Ireland, says: “Ice cream includes water ices and any article, whether frozen or chilled, and under whatever description it is sold, which is sufficiently similar to ice cream as to constitute a substitute for ice cream.” The statements just quoted seem to imply that ice cream may be made of almost anything as long as price, temperature and taste suit the requirements of the consumer. However, our concern is less to do with its composition as with regulations that have to do with the hygienic requirements of its manufacture. It may be pointed out that as things stand at present registration relates to premises and not to persons employed therein. Anyone can be employed in an ice cream factory, as he can be employed in any other kind of food factory. The matter of engaging him is left to the heads of the factory. They, as commonsense business people, with the interests of their business at heart, are not likely to engage anyone who is at sight obviously unfitted for the job. On the other hand, habits and health, especially the latter, become of peculiar importance when such a substance as ice cream is the object of manufacture. To make regulations as to the registration and inspection of premises, is one thing. It is not too easy to enforce such regulations. In the case of persons it is more delicate and difficult. If the offence be of habit it can be readily detected and dealt with. If of health, it becomes a matter for the Medical Officer of Health and his professional colleagues. Under Section 14 of the Food and Drugs Act, 1938, which came into force on October 1st, 1939, all premises in which ice cream is sold, manufactured, or stored must be registered with the local authority. The purpose for which registration is sought—sale, storage, or manufacture—must be stated, and also the nature of other business, if any, that may be carried on on the premises. If the premises appear to the local authority to be unsuitable, registration may be refused, or, if previously granted, may be cancelled. Notice of the refusal to register, or to cancel registration, must be served on the applicant or tenant of the premises by the local authority, giving reasons for the act, and the applicant or tenant may then, if he wishes, request the local authority to show cause, for the reasons given by them, why they should refuse to register or wish to cancel registration.” It need hardly be pointed out that the sole reason for registration is to enable the local authority to satisfy themselves that hygienic conditions are complied with, such as cleanliness, light, ventilation, adequate water supply and sanitation in general. Though the conditions may be complied with there is still the more serious danger that may arise from “milk‐borne diseases,” a danger that is admittedly peculiarly acute when such a substance as ice cream is the subject of manufacture or storage. The Medical Officer of Health must therefore be informed by the manufacturer if any milk‐borne disease has occurred among persons living or working in or about the premises. We may hazard the guess that it may not always be easy for the manufacturer to obtain such certain knowledge. “Milk‐borne disease” means enteric fever (including typhoid or paratyphoid), dysentery, diphtheria, scarlet fever, acute inflammation of the throat, gastro‐enteritis, and undulant fever—a formidable list—and any other disease that may be declared milk‐borne by the Minister of Health. With the best will in the world on the part of everybody concerned the enforcement of this Order, and there can be obviously no half measures in doing so, presents difficulties that can only be adequately appreciated and discussed by medical practitioners who are conversant with the nature of the disease in general and with the particular conditions that led to its occurrence. Apart, however, from its purely medical aspect, and if we consider the manufacturer we find that if he has done his duty in this respect he may have his business brought to a standstill, or at least a part or even the whole of his stock destroyed. The Medical Officer of Health is very rightly empowered, in the interests of public health, which override all other considerations, to prohibit the use for human consumption of any substance likely to convey milk‐borne disease and to order either its removal or its destruction. Compensation can be paid to the manufacturer if the Medical Officer of Health, after further enquiry, be satisfied that the suspected substance is not injurious. His notice for destruction or removal must then be withdrawn. On the other hand, compensation will not be paid if the suspected substance was actually injurious, or was made on the premises while the order of the Medical Officer was still in force. If a person feels aggrieved by the decision of the local authority he may appeal to a court of summary jurisdiction. Any change in the occupation of registered premises must be notified to the local authority by the ingoing tenant if he intends to use such premises for the purpose for which they were registered. If at the commencement of the Act of 1938 a local Act was in force dealing with the conditions for registration of premises it may remain in force unless the Minister, at the request of the local authority, declares the 1938 Act, 14 (1), to be in place of it. The use of unregistered premises renders the offender liable to a fine not exceeding £20, and for a second offence a maximum penalty of £100 and for three months imprisonment. Every street seller of ice cream must have his name and address on the barrow or container. It may be added that hotels, clubs and inns are exempt from registration, and theatres, music halls and the like are also exempt unless they manufacture ice cream on the premises. The Order of 1942 prohibited the manufacture of ice cream in catering establishments or in institutions, meaning by these terms premises previously authorised to do so by licence from the Ministry of Food or by a Food Control Committee. Institutions or households were exempt from this Order if the ice cream manufactured was to be consumed on the premises. This Order was rescinded by an Order of November 16th, 1944, and manufacture was resumed from that date. This was certainly not due to any marked increase in the milk supply. The trade demand was and is at least in part met by a permitted substitute.

Town Clerk's Office, Town Hall, Bethnal Green, E. 18th November, 1916. To the Chairman and Members of the Public Health Committee. Mr. Chairman and Gentlemen, At a recent meeting of the Public Health Committee, the Chief Sanitary Inspector reported upon legal proceedings which had been unsuccessful owing to the case of “Hunt v. Richardson” decided by a King's Bench Divisional Court of five Judges on the 2nd June, 1916, and I then reported upon the legal aspect of the case.

FINANCIAL fears are only less cruel than those of war, and lead men into extravagances which they would repudiate indignantly in their cooler moments. If the doings of the Economy Committee at Manchester in relation to children's libraries, as described in the article by Mr. Lamb in our last issue, are true, we have in them an example of a kind of retrenchment at the expense of the young which we hope is without parallel and will have no imitators. Some reduc‐tion of estimates we hear of from this or that place, but in few has the stupid policy which urges that if we spend nothing we shall all become rich been carried into full effect. Libraries always have suffered in times of crisis, whatever they are; we accept that, though doubtfully; but we do know that the people need libraries.

Heat also facilitates the transmission of water through the cell walls, thereby assisting its passage from the interior to the surface of the material; it increases the vapour pressure of water, thus increasing its tendency to evaporate; and it increases the water‐vapour‐carrying capacity of the air. In the United States the unit of heat customarily used is the British thermal unit (B.t.u.), which for practical purposes is defined as the heat required to raise the temperature of a pound of water 1° F. Heat is commonly produced through the combustion of oil, coal, wood, or gas. Heating by electricity is seldom practicable because of its greater cost; but where cheap rates prevail it is one of the safest and most efficient, convenient and easily regulated methods. Direct heat, direct radiation and indirect radiation are the types of heat generally employed. Direct‐heating systems have the highest fuel or thermal efficiency. The mixture of fuel gases and air in the combustion chamber passes directly into the air used for drying. This method requires the use of special burners and a fuel, such as distillate or gas, which burns rapidly and completely, without producing soot or noxious fumes. The heater consists simply of a bare, open firebox, equipped with one or more burners, an emergency flue to discharge the smoke incidental to lighting, and a main flue, through which the gases of combustion are discharged into the air duct leading to the drying chamber. Direct‐radiation systems also are relatively simple and inexpensive and have a fairly high thermal efficiency. A typical installation consists of a brick combustion chamber with multiple flues, which carry the hot gases of combustion back and forth across the air‐heating chamber and out to a stack. The air is circulated over these flues and heated by radiation from them. The flues are made of light cast iron or sheet iron. The air‐heating chamber should be constructed of fireproof materials. The efficiency of the installation depends upon proper provision for radiation. This is attained by using flues of such length and diameter that the stack temperatures will be as low as is consistent with adequate draught. Heating the air by boiler and steam coils or radiators is an indirect‐radiation system, as the heat is transferred from the fuel to the air through the intermediate agency of steam. Such a system costs more to install and has a lower thermal efficiency than either of the other two systems. It is principally adapted to large plants operating over a comparatively long season on a variety of materials where the steam is needed to run auxiliary machinery or to process vegetables. Large volumes of air are required to carry to the products the heat needed for evaporation and to carry away the evaporated moisture. Insufficient air circulation is one of the main causes of failure in many dehydrators, and a lack of uniformity in the air flow results in uneven and inefficient drying. The fan may be installed to draw the air from the heaters and blow it through the drying chamber, or it may be placed in the return air duct to exhaust the air from the chamber. An advantage of the first installation is that the air from the heaters is thoroughly mixed before it enters the drying chamber. It has been claimed that exhausting the air from the chamber increases the rate of drying by reducing the pressure, but the difference is imperceptible in practice. Either location for the fan is satisfactory, and the chief consideration in any installation should be convenience. Close contact between the air and the heaters and between the air and the material is necessary for efficient transfer of heat to the air and from the air to the material, and to carry away the moisture. The increased pressure or resistance against which the fan must operate because of such contact is unavoidable and must be provided for, but at other points in the system every effort should be made to reduce friction. To this end air passages should be large, free from constrictions, and as short and straight as possible. Turns in direction should be on curves of such diameter as will allow the air to be diverted with the least friction. The general rule in handling air is that a curved duct should have an inside radius equal to three times its diameter. The water vapour present in air at ordinary pressures is most conveniently expressed in terms of percentage of relative humidity. Relative humidity is the ratio of the weight of water vapour actually present in a space to the weight the same space at the same temperature would hold if it were saturated. Since the weight of water vapour present at saturation for all temperatures here used is known, the actual weight present under different degrees of partial saturation is readily calculated from the relative humidity. Relative humidity is determined by means of two thermometers, one having its bulb dry and the other having its bulb closely covered by a silk or muslin gauze kept moist by distilled water. Tap water should not be used because the mineral deposits from it clog the wick, retard evaporation, and produce inaccurate readings. The wick must be kept clean and free from dirt and impurities. The two thermometers are either whirled rapidly in a sling or used as a hygrometer mounted on a panel with the wick dipping in a tube of water and the bulbs exposed to a rapid and direct current of air. The relative humidities corresponding to different wet‐ and dry‐bulb temperatures are ascertained from charts furnished by the instrument makers, or published in engineers' handbooks. As a general rule, the more rapidly the products have been dried the better their quality, provided that the drying temperatures used have not injured them. Some fruits and vegetables are more susceptible to heat injury than others, but all are injured by even short exposures to high temperatures. The duration of the exposure at any temperature is important, since injury can be caused by prolonged exposure at comparatively moderate temperatures. The rate of evaporation from a free water surface increases with the temperature and decreases with the increase of relative humidity of the air.

The purpose of this paper is to optimize and improve a bipolar charge transport (BCT) model used to simulate charge dynamics in insulating polymer materials, specifically low-density polyethylene (LDPE).

An optimization algorithm is applied to optimize the BCT model by comparing the model outputs with experimental data obtained using two kinds of measurements: space charge distribution using the pulsed electroacoustic (PEA) method and current measurements in nonstationary conditions.

The study provides an optimal set of parameters that offers a good correlation between model outputs and several experiments conducted under varying applied fields. The study evaluates the quantity of charges remaining inside the dielectric even after 24 h of short circuit. Moreover, the effects of increasing the electric field on charge trapping and detrapping rates are addressed.

This study only examined experiments with different applied electric fields, and thus the obtained parameters may not suit the experimental outputs if the experimental temperature varies. Further improvement may be achieved by introducing additional experiments or another source of measurements.

This work provides a unique set of optimal parameters that best match both current and charge density measurements for a BCT model in LDPE and demonstrates the use of trust region reflective algorithm for parameter optimization. The study also attempts to evaluate the equations used to describe charge trapping and detrapping phenomena, providing a deeper understanding of the physics behind the model.