General Mill Research Articles

How do mud balls form in lime kilns?

Mud ball formation in lime kilns has been a persistent problem in many kraft mills, particularly for older kilns that are equipped with chains. A systematic laboratory study was conducted to examine how mud balls are formed and the key factors that affect ball formation. The results confirm the general mill experience that high moisture and high sodium contents in lime mud are the main contributing factors to ball formation. The high moisture content allows lime mud to agglomerate and grow to form balls, while the high sodium content helps make the balls hard and retain their shape. A ball formation mechanism is proposed to explain how mud balls form and grow near the kiln feed end.

Novel orbital drilling and reaming tool for machining holes in carbon fiber–reinforced plastic (CFRP) composite laminates

Carbon fiber–reinforced plastics (CFRPs) have excellent mechanical and physical properties and are widely used to manufacture structural components and skins in aviation and aerospace. Industrial applications impose high requirements on the quality and efficiency of CFRP drilling. However, it is difficult to meet these requirements with conventional methods, such as drilling and orbital drilling. To improve hole processing quality, a novel cutting tool for orbital drilling was proposed in this research. Replacing the end mill in conventional orbital drilling (COD) with this novel cutting tool can enable an orbital drilling and reaming (ODR) machining process, which can suppress defects and reduce the thrust force when machining CFRP composite laminates. The thrust forces, tool wear, cutting temperatures, and hole quality in the ODR process presented in this paper were studied experimentally. The results indicated that machining with the novel ODR tool effectively reduced the thrust force and cutting temperature observed when machining with the general end mill. Moreover, the hole quality and tool life during ODR were exceedingly better than those during COD. The experimental results showed that processing with the novel tool has immense potential to replace existing processing methods for machining holes in CFRP composite laminates.

Prediction of flexible cutting forces and tool deflections for general micro end mill considering tool run-out and deflection feedback

In this paper, a novel cutting forces and tool deflection prediction methodology for general flexible micro end mill in micro milling is proposed, which includes the effect of exact trochoidal trajectory, tool run-out, and deflection feedback together. A new mathematical model is introduced to determine the instantaneous uncut chip thickness and cutting state of cutting edge element for general micro end mill considering the exact trochoidal trajectory, tool run-out, and deflection feedback. Besides, an iterative calculation method is presented to estimate the flexible cutting forces and tool deflections, and the combined influence of tool run-out and deflection feedback on cutting forces and tool deflections is investigated by using the proposed model. To validate the effectiveness of the proposed methodology for cutting forces and tool deflections in micro milling, the micro slot milling of inclined surface have been conducted on a three-axis ultraprecision machine. The predicted and measured results show that the proposed cutting forces model performs well with the average absolute error of 4.18% in X-direction, and 5.21% in Y-direction, and the proposed tool deflection model performs well with the average absolute error of 9.60% in X-direction, and 10.10% in Y-direction when the exact trochoidal trajectory, tool run-out, and deflection feedback are all taken into account.

Social acceptability of establishing forest-based biorefineries in Maine, United States

Forest-based biomass has a significant role to play in the development of a renewable U.S. energy portfolio, especially in the context of mandated cellulosic biofuel production requirements. Biorefinery development has the potential to create economic, environmental, and social benefits. In Maine, co-location opportunities for biorefineries and existing pulp and paper manufacturing facilities could strengthen industry and mill communities. Understanding general public and local perceptions of bioenergy industries and products may play a key role in their establishment, success, and sustainability. Our aim was to compare the general Maine public and mill towns in their support for forest-based biorefineries, and we surveyed: (1) Statewide residents, and (2) Mill Town residents from 10 communities with major pulp and paper facilities. We found differences between local and state support for biorefineries across all response categories. Mill Town respondents were significantly more supportive of biorefinery projects in their communities, and overall the potential positive impacts of biorefineries were rated higher than the potential negative impacts. Both groups preferred facility siting at pulp mills no longer in operation, and Mill Town respondents expressed less concern about potential negative impacts than Statewide respondents. Our findings provide important insight into forest-based biorefinery issues important to communities. We encourage policy makers, industry leaders, and researchers to use our results as a foundation to actively engage statewide and local communities future biorefinery policies and siting proposals.

The Virtual Rolling Mill – Enhancing Product Development and Commissioning

Achenbach supplies worldwide with first-class customized rolling mills and machinery for the manufacturing of flat-rolled products from non-ferrous metals. In order to fulfil the customer-specific production requirements, Achenbach developed a wide variety of options for specific subjects. The control of the strip quality parameters like flatness or thickness in the rolling process is a key performance index.An increase of computation power in the field of industrial computers gave a chance to develop more complex model based control algorithms, which led to a significant improvement of the strip quality. In addition it gave an impulse for the development of a comprehensive mathematical model of the rolling mill.This paper will present the general virtual Achenbach Rolling Mill which is a digital representation of the rolling process in general and the behavior of the major actuators in the rolling process in detail. The behavior of drives, strip-tensions, and roll-gap is simulated in a multi-variable real-time environment. In the same environment the OPTIROLLi3®- model based controls can interact with the virtual machine. A vast number of challenges of the real rolling situation can be demonstrated by working on this ‘mill simulator’ and improved solutions are developed taking advantages from this platform. As the virtual machine allows all kinds of virtual testing without scrapping ‘real material’ a wide range of applications is possible for this virtual rolling mill. Some results from the SIL (software in loop) simulation will be presented for better clarity.

The Analysis of Tool Wear in Milling CFRP with Different Diamond Coated Tool

Carbon fiber-reinforced plastics (CFRP) are typical difficult-to-machine materials, which is easy to produce many defects such as burrs, dilacerations, layering in milling process. And selecting the appropriate cutting tool has become the key to machining CFRP with high quality and efficiency. In the paper, the machining principle of milling CFRP with new type end mill was analyzed. The diamond coating of general right-hand end mill, cross-flute router and fine-cross-nick router were used to cutting CFRP under the same cutting condition. Through the comparative analysis of the workpiece’s surface quality and tool wear, it concluded that: compared with right-hand diamond coated end mill, cross-flute diamond coated router or fine-cross-nick diamond coated router could effectively suppress the appearance of burrs and dilacerations; abnormal coating peeling appeared in the flank face of right-hand diamond coated end mill, forming the boundary wear, which accelerated wear failure; the flank wear of diamond coated cross-flute router and fine-cross-nick router were both abrasive wear. Due to having more cutting edge than cross-flute router in cutting process, the flank wear of fine-cross-nick router was slower, and the tool life was longer. So it was more suitable for cutting CFRP.

Mechanistic modeling of five-axis machining with a general end mill considering cutter runout

The accurate and fast prediction of cutting forces in five-axis milling of free-form surfaces remains a challenge due to difficulties in determining the varying cutter-workpiece engagement (CWE) boundaries and the instantaneous uncut chip thickness (IUCT) along the tool path. This paper proposes an approach to predict the cutting forces in five-axis milling process with a general end mill considering the cutter runout effect that is inevitable in the practical machining operations. Based on the analytical model of cutting edge combined with runout parameters, the expression of the rotary surface formed by each cutting edge undergoing general spatial motion is firstly derived. Then by extracting the feasible contact arc along the tool axis, a new arc-surface intersection method is developed to determine the CWE boundaries fast and precisely. Next, the circular tooth trajectory (CTT) model is developed for the calculation of the IUCT with a slight sacrifice of accuracy. In comparison with the true IUCT calculated by the trochoidal tooth trajectory model, the approximation error introduced by the circular assumption is negligible while the computational efficiency improves a lot. Finally, combining with the calibrated cutting coefficients and runout parameters, comprehensive formulation of the cutting force system is set up. Simulations and experimental validations of a five-axis flank milling process show that the novel CTT model possesses obvious advantages in computing efficiency and accuracy over the existing approaches. Rough machining of a turbo impeller is further carried out to test the practicability and effectiveness of the proposed mechanistic model.

Analysis and Acute Toxicity Determination of the Dyestuff in the Effluent of a Textile Manufacturing Company Located In The Eastern Part of Nigeria

In this study the effluent from General Cotton Mill Limited was analysed with respect to the dyestuff. The General Cotton Mill Ltd is an industry involved in textile manufacture which involves a lot of use of dyestuff and since some dyestuff can be environmental hazards, it became necessary to investigate the effluent to ascertain the safety of the effluent. The effluent was extracted with acetone, hexane and petroleum spirit (40 0 C- 60 0 C).Petroleum spirit was the best extracting solvent. The extract was chromatographically separated and subjected to UV visible, infrared and LD50 determination. There were two major dye components in the extract, blue and purple coloured dyes. The UV corresponding to the blue dye is 500nm while that of the purple dye is 520nm. The functional groups obtained from the IR are primary amide (RCONH2), sulphonic group (HSO3), vinyl group (-CH=CH2), alkyl chloride (C-Cl), aromatic amine group. These IR frequencies are in consonant with that found in most fiber reactive dyes. At an LD50 test of 500mg/kg, no death or sign from experimental animal (mice) was observed, which suggest that the extract dye is non toxic.

Image de marque et internet. Comprendre, éviter et gérer l’effet « Streisand »

Afin de gérer leur image de marque, les entreprises peuvent contrôler toutes les informations les concernant. Cette volonté peut aller jusqu’à influencer les informations disponibles sur Internet. Dans ce cas, un processus contre-productif, l’effet « Streisand », peut s’enclencher. Ce processus aboutit à une plus grande diffusion d’une information qui serait restée confidentielle sur Internet, s’il n’y avait pas eu la volonté de la manipuler, voire de la retirer. La présentation de cet effet, à travers trois cas réels rencontrés par Ralph Lauren, General Mills et Nestlé, permet d’illustrer ce processus. Ces cas soulignent les limites des réponses communicationnelles et juridiques classiques, tout en apportant des réponses visant à gérer au mieux cet effet. Enfin, l’impact de l’effet « Streisand » sur les performances de l’entreprise et de son image de marque est souligné.

A study on the machining of compressor rotors using formed tools

In this paper it was suggested the machining method that can improve machining accuracy and reduce the machining time applying the formed tools based on the rotor shape feature to finishing machining for efficient machining of asymmetric rotors. For machining the complicated asymmetric rotor profile, machining area is divided and formed tools are manufactured based on the rotor feature., and the efficient machining method of screw motor was proposed using the formed tools and four axis machining devices. With the suggested machining method, machining time could be reduced compared to the general end mill machining method, and the machining errors of the proposed method could be within the allowable tolerance of the product so as to carry out the precise machining.

A Two-Phase Heuristic for the Production Scheduling of Heavy Plates in Steel Industry

In this paper, the production scheduling of heavy plates is considered. Different from general hot rolling mill, the reheating furnace scheduling shares the same importance with the hot rolling scheduling due to the special characters of heavy plates such as the large differences in weight and dimension. One major characteristic of the reheating furnace is that it can simultaneously process multiple slabs. When the furnace is full, a slab can be drawn in only if the head slab in the furnace has been drawn out. Therefore, the practical heating time of a slab is variable and besides the weight and dimension, is also dependent on not only the slab heating sequence but also the furnace capacity. Since there is no buffer between the reheating furnace and the hot rolling line, a finished slab will reside in the furnace until the hot rolling line is available. To solve this problem, a two-phase heuristic is proposed. In the first phase, only the hot rolling scheduling problem is considered and a scatter search is developed for it. In the second phase, a decision tree-based heuristic is constructed to obtain the corresponding reheating furnace schedule. The experimental results on real production data show that the two-phase heuristic outperforms the current manual scheduling system.

Cogeneration in Sugar Industries: Technology Options and Performance Parameters—A Review

ABSTRACT This article presents a review of different technological options that are presently being practiced by sugar mills, and technological options that are identified as potentially promising future technologies. Different indices used to gauge the thermodynamic performance of cogeneration plants and facilitate the comparison of alternative systems are discussed. The most important performance parameters used to assess the steam turbine cogeneration plants in general and sugar mill cogeneration plants in particular are defined and developed. Criteria such as energy utilization factor, heat-to-power ratio, fuel energy savings ratio, exergetic efficiency and power generated per tonne of cane (tc) prove to be more important and relevant. Biomass-integrated gasifier/gas turbine cogeneration (BIG-GT) and biomass gasifier combined with steam injected gas turbine cogeneration (BIG-STIG) are considered as potentially promising future technologies. The existing modern, high pressure, high efficiency, steam turbine cogeneration plants generate 115–120 kWh/tc, while BIG-GT and BIG-STIG are potentially capable of generating up to 270–275 kWh/tc. Cogeneration plants using backpressure and condensing steam turbines perform with energy (First Law) and exergetic (Second Law) efficiency of approximately 60–70 % and 22–25%, respectively. The steam consumption in sugar mills at present varies from 480–550 kg/tc, while electricity consumption ranges between 16–22 kWh/tc (32–40 kWh/tc for electrified mills). These performance indices will help plant designers and engineers in improving their choice of system configuration and developing alternative schemes.

Extracting cutting constants via harmonic force components for a general helical end mill

Mechanistic cutting constants serve well in predicting milling forces, monitoring the milling process as well as in helping to understand the mechanistic phenomena of a machining process for a unique pair of workpiece and cutter materials under various types of cutting edge geometry. This paper presents a unified approach in identifying the six shearing and ploughing cutting constants for a general helical end mill from the dynamic components of the measured milling forces in a single cutting test. The identification model is first presented assuming the milling force is measured with a known phase angle of the cutter spindle. When the phase angle of the cutter rotation is not available, as is the case for most milling machines, it is shown that the true phase angle can be identified through the theoretical phase relationship between the different harmonic components of the milling forces measured with an arbitrary phase angle. The numerical simulation and the experimental results for ball and cylindrical end mills are presented to demonstrate and validate the identification methods.

Mechanistic identification of specific force coefficients for a general end mill

The paper presents expressions for semi-empirical mechanistic identification of specific cutting and edge force coefficients for a general helical end mill from milling tests at an arbitrary radial immersion. The expressions are derived for a mechanistic force model in which the total cutting force is described as a sum of the cutting and edge forces. Outer geometry of the end mill is described by a generalized mathematical model valid for a variety of end mill shapes, such as cylindrical, taper, ball, bull nose, etc. The derivations follow a procedure originally proposed for a cylindrical end mill. The procedure itself is improved by including the helix angle in evaluation of the average edge forces. The resulting expressions for the specific force coefficients are verified by simulations and experiments.

Treatability of Bleached Kraft Pulp and Paper Mill Wastewaters in a New Zealand Aerated Lagoon Treatment System

The effectiveness of the two biological treatment systems operating at a New Zealand bleached kraft softwood integrated pulp and paper mill was assessed. The two systems operate in different configurations. Treatment system A, which receives general mill wastewaters and chlorination stage bleaching discharges utilises deep, aerated lagoons and has a 4.5 day retention time. Treatment system B, which receives alkali extraction bleaching wastewaters and foul condensates, uses a lagoon system with a retention time of 45 days. Detailed chemical analyses of the untreated and treated wastewaters were made. Mass balances were calculated for a range of physical parameters and for specific chlorinated and non-chlorinated organic constituents. Significant differences in the treatability of various constituents were found. In particular, while system A was able to reduce levels of AOX by 65%, no significant reduction in AOX occurred in system B. In contrast, system B reduced levels of chloroacetic acids by 84% while system A did not achieve any statistically significant removal of these compounds. The treatability of chlorophenolic compounds also differed. System A was unable to remove chlorophenols and chloroguaiacols while system B did not reduce levels of chlorocatechols. These results confirm that the treatability of bleached kraft pulp and paper mill wastewater constituents is dependent upon the characteristics of the treatment systems and the compositions of the wastewaters.

Evaluation of a general purpose abrasive mill for pearling of coarse cereals and dehusking of pulses

SummaryA general purpose abrasive mill, developed to pearl and dehusk cereals and pulses, has integral milling and cleaning chambers and a 10‐grinding wheel rotor driven by a 3.7 kW motor. Its capacity is between 96 and 340 kg h−1, depending upon the grain being handled, with a maximum dehulling efficiency of 75%. The cost of processing varied from Rs 4.5 to 9.2 per tonne of feed. It could be owned, operated, and manned by small‐scale processors in rural and semi‐urban areas.

Tandem mill scheduling as a two point boundary value problem

We consider the problem of a tandem cold rolling mill to achieve correct output gauge, and satisfactory shape, and surface finish. The essential process variables are roll force, shape and thermal roll crown. The formulation of the equations for these key variables is described. The scheduling problem is formulated as a constrained two point boundary value problem. This is solved using conjugate gradient and projection techniques developed for optimal control problems. Results showing the improvements which can be made in strip shape and general mill operating conditions, by optimising the schedules, are included and discussed.

Optimal Scheduling of a Tandem Cold Rolling Mill

We consider the problem of a tandem cold rolling mill to achieve correct output gauge, and satisfactory shape, and surface finish. The essential process variables are roll force, shape and thermal roll crown. The formulation of the equations for these key variables is described. The scheduling problem is formulated as a constrained two point boundary value problem. This is solved using conjugate gradient and projection techniques developed for optimal control problems. Results showing the improvements which can be made in strip shape and general mill operating conditions, by optimising the schedules, are included and discussed.

Metabolic aspects of acid-base change.

The state of metabolic acidosis involves changes of a varied and subtle nature in other organs as well as in the kidney. This fact has been illustrated in metabolic studies with glutamine, a major substrate of the kidney and of various other organs. In addition to the well-described increase in renal glutaminase enzymes, the hexose monophosphate-shunt enzymes also are much more active during metabolic acidosis; this phenomenon is limited to the kidney; its exact meaning remains speculative, but its possible relation to renal excretion of acid, lipogenesis, and gluconeogenesis during acidosis has been discussed. In the kidney there are metabolic changes associated with ammonium chloride acidosis that affect the basic mechanisms of gene-directed growth. There is a renal regenerative process during this kind of acidosis that resembles in some respects the compensatory hypertrophy in the remaining kidney after unilateral nephrectomy, from which it also differs in important ways. Lastly, we must now regard the role of glutamine in renal metabolism as an affair that goes well beyond the specific needs of formation of ammonia during the normal and acidotic states. Glutamine enters the general metabolic mill of the kidney, its carbon skeleton is incorporated into all the major tissue components, and it is an important source material for gluconeogenesis in the kidney; all of these renal functions of glutamine are increased during metabolic acidosis. Thus there is a fruitful field of exploration ahead, not only in the biochemical aspects of the renal response, but also in the metabolic interrelations among different organs during various types of acid-base change. This article, in concentrating on metabolic acidosis, gives only a glimpse of a broader picture to come.

FIGLU excretion. A screening test for folic acid deficiency in pregnancy.

BJOG: An International Journal of Obstetrics & GynaecologyVolume 69, Issue 5 p. 739-741 FIGLU EXCRETION A Screening Test for Folic Acid Deficiency in Pregnancy Elizabeth D. Hibbard M.B., D.(Obst.)R.C.O.G., Elizabeth D. Hibbard M.B., D.(Obst.)R.C.O.G. Department of Pathology, Newsham General Hospital and Mill Road Maternity Hospital LiverpoolSearch for more papers by this author Elizabeth D. Hibbard M.B., D.(Obst.)R.C.O.G., Elizabeth D. Hibbard M.B., D.(Obst.)R.C.O.G. Department of Pathology, Newsham General Hospital and Mill Road Maternity Hospital LiverpoolSearch for more papers by this author First published: October 1962 https://doi.org/10.1111/j.1471-0528.1962.tb01273.xCitations: 17AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume69, Issue5October 1962Pages 739-741 RelatedInformation