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This paper aims to use the second law of thermodynamic to evaluate the potential of gear-ring turbulator in a three-dimensional heat exchanger tube. Accordingly, a numerical simulation is performed to obtain the irreversibilities in a three-dimensional heat exchanger tube equipped with some gear-ring turbulators for turbulence regime.

A numerical simulation is performed to obtain the irreversibilities in a three-dimensional heat exchanger tube equipped with some gear-ring turbulators for turbulence regime. The analysis is carried out based on shear stress transport (SST) k-ω turbulent model. The influences of different parameters containing tooth number, free-space length ratios and Reynolds number on frictional and thermal irreversibilities and Bejan number are discussed.

The results indicated that the thermal irreversibility reduces by decreasing the tooth number. For example, the thermal entropy generation decreases about 25.81 per cent by decreasing the tooth number in the range of 24 to 0 at Re = 6,000. Moreover, the frictional entropy generation decreases by increasing the tooth number as the gear with more tooth number causes a lower flow disturbance.

The present study arranged a numerical work to study the potential of a gear-ring turbulator in a heat exchanger tube from first and second laws of thermodynamic viewpoint. The turbulent flow is considered for this problem. The literature review showed that the usage of a gear-ring turbulator in a heat exchanger tube is not investigated from the second law of thermodynamic viewpoint by previous studies. As a result, the influences of different parameters containing tooth number, free-space length ratios and Reynolds number on frictional and thermal irreversibilities and Bejan number are discussed.

The study aims to the distribution rule of lubricating oil film of full ceramic ball bearing and improve its performance and life.

The paper established an analysis model based on the fluid–solid conjugate heat transfer theory for full ceramic ball bearings. The distribution of flow, temperature and pressure field of bearings under variable working conditions is analyzed. Meanwhile, the mathematical model of elastohydrodynamic lubrication (EHL) of full ceramic ball bearings is established. The numerical analysis is used to study the influence of variable working conditions on the lubricant film thickness and pressure distribution of bearings. The temperature rise test of full ceramic ball bearing under oil lubrication was carried out to verify the correctness of simulation results.

As the speed increased, the oil volume fraction in full ceramic ball bearing decreased and the surface pressure of rolling element increased. The temperature rise of full ceramic ball bearings increases with increasing speed and load. The lubricant film thickness of full ceramic ball bearing is positively correlated with speed and negatively correlated with load. The pressure of lubricating film is positively correlated with speed and load. The test shows that the higher inner ring speed and radial load, the higher the steady-state temperature rise of full ceramic ball bearing. The test results are in high agreement with simulation results.

Based on the fluid–solid conjugate heat transfer theory and combined with Reynolds equation, lubricating oil film thickness formula, viscosity temperature and viscosity pressure formula. The thermal analysis model and EHL mathematical model of ceramic ball bearings are established. The flow field, temperature field and pressure field distribution of the full ceramic ball bearing are determined. And the thickness and pressure distribution of lubricating oil film in the contact area of full ceramic ball bearing were determined.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2023-0126/

Starch is a valued structural component of many foods. Considers the behaviour of starch as a macronutrient and as a structural component of food materials.

The study here examines how business actors adapt to changes in networks by analyzing their perceptions or their network pictures. The study is exploratory or iterative in the sense that revisions occur to the research question, method, theory, and context as an integral part of the research process.

Changes within networks receive less research attention, although considerable research exists on explaining business network structures in different research traditions. This study analyzes changes in networks in terms of the industrial network approach. This approach sees networks as connected relationships between actors, where interdependent companies interact based on their sensemaking of their relevant network environment. The study develops a concept of network change as well as an operationalization for comparing perceptions of change, where the study introduces a template model of dottograms to systematically analyze differences in perceptions. The study then applies the model to analyze findings from a case study of Norwegian/Japanese seafood distribution, and the chapter provides a rich description of a complex system facing considerable pressure to change. In-depth personal interviews and cognitive mapping techniques are the main research tools applied, in addition to tracer studies and personal observation.

The dottogram method represents a valuable contribution to case study research as it enables systematic within-case and across-case analyses. A further theoretical contribution of the study is the suggestion that network change is about actors seeking to change their network position to gain access to resources. Thereby, the study also implies a close relationship between the concepts network position and the network change that has not been discussed within the network approach in great detail.

Another major contribution of the study is the analysis of the role that network pictures play in actors' efforts to change their network position. The study develops seven propositions in an attempt to describe the role of network pictures in network change. So far, the relevant literature discusses network pictures mainly as a theoretical concept. Finally, the chapter concludes with important implications for management practice.

I think that psychologically it is most important that, as long as possible, every effort should be made to maintain the supply of foods enabling dishes of an attractive character to be produced. The morale of the big cities must be maintained, and as a large proportion of the population in these cities takes at least one meal a day in a public eating‐place, and, moreover, as the housewife relies on the pastrycook for an ever increasing proportion of her non‐basic foods, not to mention the basic foods themselves, every effort must be made to maintain producers of foods in such a position that they are able to supply cakes, confectionery, biscuits and so on. And in suggesting this I am being a realist; I have experienced the depression of the “ Berliner ” when it became impossible for this kind of food to be bought except by the very rich or the very powerful. It is, in fact, not sufficient to provide the necessary calories, the necessary vitamins, the necessary “trace” elements, as the Americans have called them; the method of presentation must be studied, for this is of vital importance in the maintenance of good health. From the scientific point of view it is deplorable that six months had to pass before the Ministry of Food appointed a scientific adviser. Dr. Drummond's influence in that capacity should help to straighten out some of the muddles into which the Ministry have apparently been led. It is obvious that our vaunted preparedness did not extend to the realm of food. One important point must be borne in mind, namely, that although the Ministry did not appoint a scientific adviser until February, 1940, they had at their disposal the experts of the Food Investigation Board and of those research associations in food science which I have already mentioned. Possibly, therefore, the Ministry would consider that it was sufficiently well served, and that these bodies would have been able to produce the briefs on which the Minister could plead. But the Food Investigation Board—and I am speaking as an exmember of that body—is essentially equipped for long‐distance research work, and not for the solution of problems of immediate importance. No one has greater respect for the work of fundamental importance which the staff of the Food Investigation Board have produced than I, but except for practical problems concerned with a limited number of food products—beef tendering, bacon curing, fruit preservation—they are not in direct touch with practice. It has been a very sound policy to restrict the activities of their staffs to the solution of problems of fundamental nature, the results of which, when published, would be applied to practical problems by the chemists attached to foods producing firms. I cannot pass from this section without comment on the very admirable statement of certain aspects of the work of the Research Associations clearly expressed by the Director of the Research Associations of British Flour Millers, Dr. Moran, in the journal Milling recently. He gives in a few clear sentences his understanding of the functions of a research association. His words are: “The research association has four clear functions: (1) as a sentinel of progress and development not only in this country but throughout the world; (2) to carry out continuously research which the individual miller—certainly the small miller—could not undertake; (3) to deal with the day‐to‐day problems of members; (4) generally to improve the efficiency of the industry and the quality of its products by the greater application of scientific methods.” The degree to which these functions are realised by any association is an excellent yardstick by which to measure its success. The milling industry of the country is to be congratulated that the director of their research association has such definite ideas, and the country as a whole is to be congratulated that the council of at least one research association in food is sufficiently alive to the importance of their duties to allow such statements as I have quoted to be published. It certainly stimulates interest and confirms the faith which should be placed in science as applied to a basic industry. The food manufacturer has, naturally, been rationed in respect of raw materials, as have been the members of the public. Fats, sugar and meat have been available in decreased quantities, but with the advent of rationing a distinct lessening of wastage of food follows and no real difficulties of shortage have become apparent. The attention of chemists has however, been directed to “ alternatives.” I object to the word “ substitute,” because in the minds of the majority this suggests something inferior. In many cases the alternative is to use something more expensive, something which under normal conditions would not be used. For example, at the moment glucose, more expensive than cane sugar, has taken the place of a portion of the usual sugar; lactose, the sugar of milk, is being used although it costs about twice as much as cane sugar and has a sweetening power far below that of the usual sugar. But sugars are not only used for sweetening, as so many people seem to think. Their presence in a cake or other bakery product has a most important chemical or physicochemical action on the gelatinisation of the starch of the flour, and an adequate amount of sugar is therefore essential if the character of the product is not to be impaired. The use of alternatives is not to be confused with sophistication; the replacement of non‐available constituents must be differentiated from the dressing‐up of one thing to make it look like another. The artificial colouring of a cake with a brown colour and the description of the resultant product as a chocolate cake, is to be condemned, although such a cake may be as nutritious as the cake to which chocolate powder had been added. The caffeine of coffee and tea is of importance in giving a slight feeling of stimulation to the tired worker, and therefore roasted cereals, as supplied in Germany during the last war, and again to‐day, cannot be considered alternatives for coffee, neither can mixture of fruit leaves take the place of tea. It is to the scientist that Germany owes the development of her substitute and alternative foods. These substitutes and alternatives are far better than those Germany had in 1914–18, because very early on she enlisted her chemists, or rather those who had not been expelled, into the service of her Four Year Food Plan. Chemical research in the totalitarian states is in practice Government‐controlled—in practice only because in theory there has been no bar to private investigation—but the Four Year Plan in Germany as applied to food entailed the direction of food investigations by State officials and although not so obvious in Italy, the same thing obtained there for a number of years. The natural outcome is control of food production. An interesting example is to be found in the tomato‐growing districts in Italy. Through the research station at Parma the farmers and the factories dealing with tomatoes are definitely directed. The former are told what seed to plant, how much, how to till their land, how to manure it, when to gather their crops, how much to gather, the quantity to pack as fresh fruit, the quantity to send to the factories to be made into purée.

This chapter contributes to the existing literature on institutional theory and international business research by integrating the concepts of polycentrism and institutional learning to examine how MNEs from emerging economies invest in developed countries. We argue that equity-based market entry modes and non-equity-based modes create different needs for learning about economic, regulatory and political institutions; entry modes with or without local partners lead to different levels of institutional embeddedness and institutional learning speeds. Finally, the content of institutional knowledge also determines its transferability and adaptability. We emphasize the importance of recognizing the integrated nature of economic, regulatory and political institutions from a polycentric perspective and discuss their change in different situations.

The purpose of this study was to analyze the influence of epichlorohydrin (ECH) concentration and reaction time on the food-grade resistant starch production and its pasting properties by using native cassava starch of Misiones-Argentina origin.

Cassava starch was modified using ECH (0.30 and 0.15 per cent) during 4 or 8 h. Digestibility was evaluated by determining resistant starch as total dietary fiber. Pasting properties and the cross-linking degree were studied using a micro-viscoamylograph (Brabender).

Resistant starch content was not influenced by ECH concentration and reaction time. Cross-linking was detected at higher reaction times (8 h) and ECH concentrations (0.30 per cent), where a decrease in viscosity peaks by more than 80 per cent was observed. Both pasting temperature and breakdown were increased, whereas a decrease in retrogradation was detected.

Starches can be suitable for different food applications. This is because of the ability to modify its pasting properties and the invariability of the in vitro digestibility of cassava starch as a result of using ECH (at concentrations approved by local and regional legislation) and reaction times of 4 and 8 h.

Information related to the modification of cassava starch using ECH is scarce or not available nowadays in literature.

The aim of this paper is to investigate the relationship between the ring structure of the twisted partial skew generalized power series ring RG,≤;Θ and the corresponding structure of its zero-divisor graph Γ̅RG,≤;Θ.

The authors first introduce the history and motivation of this paper. Secondly, the authors give a brief exposition of twisted partial skew generalized power series ring, in addition to presenting some properties of such structure, for instance, a-rigid ring, a-compatible ring and (G,a)-McCoy ring. Finally, the study’s main results are stated and proved.

The authors establish the relation between the diameter and girth of the zero-divisor graph of twisted partial skew generalized power series ring RG,≤;Θ and the zero-divisor graph of the ground ring R. The authors also provide counterexamples to demonstrate that some conditions of the results are not redundant. As well the authors indicate that some conditions of recent results can be omitted.

The results of the twisted partial skew generalized power series ring embrace a wide range of results of classical ring theoretic extensions, including Laurent (skew Laurent) polynomial ring, Laurent (skew Laurent) power series ring and group (skew group) ring and of course their partial skew versions.

This paper aims to provide discussions of a numerical method for bubbly flows and the interaction between a vortex ring and a bubble plume.

Small bubbles are released into quiescent water from a cylinder tip. They rise under the buoyant force, forming a plume. A vortex ring is launched vertically upward into the bubble plume. The interactions between the vortex ring and the bubble plume are numerically simulated using a semi-Lagrangian–Lagrangian approach composed of a vortex-in-cell method for the fluid phase and a Lagrangian description of the gas phase.

A vortex ring can transport the bubbles surrounding it over a distance significantly depending on the correlative initial position between the bubbles and the core center. The motion of some bubbles is nearly periodic and gradually extinguishes with time. These bubble trajectories are similar to two-dimensional-helix shapes. The vortex is fragmented into multiple regions with high values of Q, the second invariant of velocity gradient tensor, settling at these regional centers. The entrained bubbles excite a growth rate of the vortex ring's azimuthal instability with a formation of the second- and third-harmonic oscillations of modes of 16 and 24, respectively.

A semi-Lagrangian–Lagrangian approach is applied to simulate the interactions between a vortex ring and a bubble plume. The simulations provide the detail features of the interactions.

Piston ring dynamic problem plays an important role in the lubricant characteristics of a reciprocating engine, which lead to engine wear and the increased consumption of lubricating oil. A cavitation analysis of the piston ring lubrication with two-dimensional Reynolds equation has rarely been reported owing to the complex working condition. The purpose of this study is to establish a precise model that can provide guidance for the design of the piston ring.

In this paper, a cavitation model and its effect on the piston ring lubrication was studied in a simulation program based on the mass-conserving theory which is solved by means of the Newton–Raphson method. In this study, some models such as mixed lubrication, asperity contact, blow-by/blow-back flow and cavitation have been coupled with the lubrication model.

The established model has been compared with the traditional model that deals with cavitation by using the Reynolds boundary condition algorithm. The cavitation zone, pressure distribution and density distribution between the piston ring and the cylinder have also been predicted. Studies of the changing trend for the pressure distribution and the cavitation zone at few typical crank angles have been listed to illustrate the cavitation changing rule. The analysis of the results indicates that the developed simulation model can adequately illustrate the lubrication problem of the piston ring system. All the analyses will provide guidance for the oil film rupture and the reformation process.

A two-dimensional cavitation model based on the mass-conserving theory has been built. The cavitation-forming and -developing process for the piston ring–liner lubrication has been studied. Non-cavitation occurs in the vicinity of top dead center and bottom dead center. The non-cavitation period will be longer in the vicinity of 360° of crank angle. The density distribution in the cavitation zone can be obtained.