Design Evaluation of Air Gap in a Ceiling Fan—A Simulation Case Study

Lower air gap in ceiling fan motors leads to higher rework at an assembly. It is suspected that inappropriate component design specifications may be the root cause. To resolve the issue and prevent worker dissatisfaction, a study is undertaken to evaluate the extent of air gap variation when components are produced as per design. First air gap is modeled as a function of different parameters of a fan assembly. The theoretical probability distribution of this modeled air gap function, though not impossible to obtain, is quite complex to derive. Thus this model is then used to generate data on air gap using Monte Carlo simulation. Analysis of the data shows that lack of process capability, not inappropriate design specifications, is mainly responsible for higher rework. The findings were discussed with management and were accepted. As a sequel to the study, a cost-benefit analysis is being undertaken for procuring new and improved machines.     

A Note On “Determination of Coordinated Maintenance Scheduling Frequencies For A Group Of Machines”

In this note we present a simpler total cost model when the repair work on a group of machines is coordinated. We demonstrate that coordination of repair work may not be economically beneficial under the generally accepted conditions. We suggest an improvement in the solution procedure in order to consider coordinated as well as uncoordinated repair policies for a group of machines.     

Laser Powder Deposition of a Near Net Shape Injection Mold Core — A Case Study

Directed Light Fabrication (DLF) is a direct deposition process that fuses metal powder, in the focal zone of a laser beam, to form fully fused near net shaped components. A fully associative 3D design-through-manufacturing model is presented as a case study for the fabrication of a near net shaped injection mold core part. This study evaluates the ability to move from a parametric 3D model, integrated into a manufacturing model, to creating a control file used to produce a component using a nickel base alloy. Evaluation of the efficiency, quality, attributes and limitations of the process is reported. A high degree of accuracy for large feature location was obtained but improvements in surface finish and the dimensional accuracy of small features are required to fully realize benefits of this technology. The competing benefits of deposition accuracy and manufacturing time are discussed in terms of computerized numerical control code generation.     

A Comparative Evaluation of the Properties of some Tablet Disintegrants

The subject of the study is a cooperative evaluation of the properties of different disintegrants: starches (corn, maize, potatoe, rice) and derivatives (STARX 1500, carboxymethylstarches as PRIMOJEL or EXPLOTAB); celluloses (AVICEL, ELCEMA) and derive ted products as methylcellulose (METHOCEL), carboxymethylcellu-lose (sodium salt, NYMCEL, AC DI SOL), low substituted hydroxy-propylcellulose (L-HPC); macromolecules (Alginic acid, AMBERLITE IRP 88, ESMA SPRENG, Pectins, a.s.o.); finely divided solids (AEROSIL, VEEGUM). To realise this comparative study, different methods of evaluation of disintegrants physical properties are choosen, and wettability (contact angle), water uptake and swelling of the products measured. The disintegrants are also included in a calcium phosphate based tablet formula, and the disintegration is studied. The mechanism of action of the disintegrants is shortly discussed, and an approximate price/efficiency ratio given.

The results of the work permit a better choice of an appropriated disintegrant.

Purpose of tablets formulation is now Co obtain very short disintegrating times so that to that liberation of drug can begin without delay as soon as tha tablet is in contact with gastric juice.

Therefore, it is now iaportant to look for the sure efficient disiutugrauts, and so, many Materials are avalaible from industry.

Purpose of present study was to compare some physical properties of these different disintegranta.     

Studies of Floating Dosage Forms of Furosemide: In Vitro and In Vivo Evaluations of Bilayer Tablet Formulations

For the purpose of enhancement the bioavailability of furosemide (FR), a floating dosage form with controlled release of FR was designed in this study. Because of the lower solubility of active material in the gastric medium, it was first enhanced by preparing an inclusion complex of FR with beta-cyclodextrin (β-CD) in a 1:1 proportion using the kneading method. Following the design of dosage form, bilayer floating tablets were prepared. After dissolution rate studies were performed using the continuous flow-through cell method, the formulation that provided delivery of active material near the target profile was given to six healthy male volunteer subjects, and in vivo tests were performed. It was determined by radiographs that floating tablets prepared by adding BaSO₄ stayed in the stomach for 6 hr. Further, values of the area under the plasma concentration-time curve (AUC) obtained with the floating dosage form were about 1.8 times those of the conventional FR tablet in blood analyses; maximum and minimum plasma concentrations were also found to be between the desired limits. In urine analyses, the peak diuretic effect seen in classical preparations was decreased and prolonged in floating dosage forms. Also, a considerably significant correlation was detected between in vivo results and in vitro data of the dissolution rate, and it was concluded that the modified continuous flow-through cell method is usable for in vitro dissolution rate tests of floating dosage forms.     

RKKY Interactions in a Bilayer Olympicene Structure: A Monte Carlo Study

Using Monte Carlo simulations, we study the effect of the Ruderman–Kittel–Kasuya–Yosida (RKKY) interactions in a bilayer olympicene structure, with mixed spins (σ = 3/2 and S = 2) in the Blume–Capel model. The studied system is formed by two magnetic layers (N ₁ and N ₂), separated by a number of non-magnetic layers (NM). We first elaborate the ground-state phase diagrams and then we found that from 4 × 5 = 20 phases possible, only 12 configurations are found to be stable. For low reduced temperature values, the partial magnetizations are found to be in good agreement with the corresponding ground-state phase diagrams. The critical temperature is displaced towards lower temperatures. This is due to the fact that the increasing of the number of non-magnetic layers increases the effect of the RKKY interaction. We have interpreted the behaviors of the magnetic hysteresis for this model.     

Radiation Tolerance Evaluation of the Ti/Au Bilayer TES Microcalorimeter

We have developed Ti/Au bilayer transition-edge sensor (TES) microcalorimeters for future X-ray astrophysical satellite missions such as DIOS. One possible concern on the space use of TES microcalorimeters is its radiation tolerance. We have evaluated the performance of a Ti/Au bilayer (30/40 nm thick) TES microcalorimeter with 1.5  \(\upmu \) m thick Au absorber, before and after irradiation of 150 MeV proton beam with a total dose of 10 krad, corresponding to 10 years in the low Earth orbit. No significant changes on transition temperature, sensitivity, normal resistance, and critical current were observed. The energy resolution for 5.9 keV X-rays was 5.6  \(\pm \)  0.3 eV (FWHM) after the irradiation, which was slightly worse than 5.1  \(\pm \)  0.3 eV before the irradiation. We consider that our TES has sufficient radiation tolerance in orbit.     

A Study of the Swelling of Tablet Excipients Using Video Recording

Abstract

A video recording technique was used to study microscopically the svelling characteristics of individual tablet disintegrant particles in vater. Feret's diameter, projected area and dimensionless shape factors such as elongation ratio, bulkiness factor and surface factor of various particle profiles were determined. Hydrated particles of cross-linked sodium cazboxymethylcellulose (Ac-Di-Sol) and loW substituted sodium carboxymethylcellulose (Nymcel ZSB10 and ZSD16) had high Feret's diameter and projected areas. Swelling in their case vas due to the hydration of macromolecules. Hydrated microcrystalllne CellUlOSe (Avicel PHlOll partlcles had a narrov distribution of both Feret's diameter and projected area. The lov degree of svelling In these particles vas due to entry of vater into particle pores. Fibrous particles of Nymcel ZSB10 retained their elongated shape even after swelling fully. Ac-Di-Sol and Nymcel ZSD16 particles hovever svelled appreciably along their breadth also and assumed a less elongated profile than vhen dry. The order for increase in projected area diameter after hydration was Ac-Di-Sol > Nymcel ZSB10 > ZSD16 > Avicel PH101.     

Solving Large Single-Model Assembly Line Balancing Problems—A Comparative Study

A comparative study is made between three methods for balancing single-model assembly lines. These include: 10-SP, which selects the best of ten single-pass solutions; ARCUS—a random multi-pass method, and MALB, an iterative backtracking method. The assembly tasks contain up to 140 work elements with widely differing precedence structures. Measurements of the Balance Delay are used for comparing the solution efficiencies and computation times are also compared. The experiments show significant differences between the three line balancing methods and that these differences are accentuated for certain conditions of task size, precedence structure and the imposed balancing requirements. It is shown that 10-SP is yet another simple but effective technique for balancing single-model assembly lines.     

A “Six Sigma”© Case Study: G.E.P. Box's Paper Helicopter Experiment—Part B

This article presents an application of the “Six Sigma” DMAIC model to G.E.P. Box's famous “paper helicopter” experiment. The Improve and Control Phases are presented here. The Define, Measure, and Analyze Phases were presented in an earlier paper. The intent of this article is to present the reader with a case study for structuring a “Six Sigma” project.     

Evaluation of Formal in-Case in as a Tablet Disintegrant

Formalin-casein has been proposed as a tablet disintegrant under the trade name o f Esma-sprenq. The significance of water penetration on the disintegration mechanism has been evaluated by using different tablet constituents and by modifyinq the hydrophobicity inside the tablet. Formalin-casein appears to be a powerful disintegration agent when a sufficiently hydrophobicity network has been created within the tablet. Swelling of the disintegrant has also been considered and evaluated under different conditions. However, this mechanisrn appears to be negligible in the disintegration process. In addition, a number of compressional characteristics were studied.     

Organic Magnets—A History

This article summarizes the history associated with the research targeting the design and synthesis of new classes of magnets, namely, those prepared via conventional synthetic organic chemistry methodologies and where the building blocks of the magnetic materials are comprised of molecules as opposed to atoms and as a consequence frequently possess electron spins in p‐orbitals. Aspects of new chemistry and new materials evolved from these worldwide studies are highlighted.     

The Method Based on Original DBFs for Fast Estimation of Waveform Distortions in Ship Systems—Case Study

This paper deals with the problem of fast recognition of harmonic distortions by means of a wavelet transform. A method of fast detection of a frequency band affected by the high-frequency content and time of its occurrence is described. It is based on the auxiliary waveform distortion band factors (DBFs) calculated on the basis of wavelet coefficients. The merits of the presented method, as well as its limitations, are described on the basis of real voltages registered in ships' electrical power systems. This method is a part of the method based on the complementary application of Fourier and wavelet transforms, which was described in the previous papers of the author. However, this paper describes new research results and an expanded analysis exclusively focused on the aforementioned DBFs.     

Developing Biotechnology Clusters in Non-high Technology Regions—The Case of Austria

This paper explores the role of distant knowledge links and policy actions for the development of biotechnology clusters. It seeks to challenge the prevailing view that the birth and early development of high technology industries are always spontaneous phenomena which are mainly based on local knowledge. Departing from the theoretical concept of regional innovation systems (RIS), a distinction between “RIS with strong potentials for high technology industries” and “RIS with weak potentials for high technology industries” will be drawn. It will be argued that in the latter case the development of biotechnology clusters is more dependent on distant knowledge sources and proactive policy efforts to create a favourable environment for high technology activities. Furthermore, it will be shown that a far-reaching transformation of the regional innovation system is crucial for catching-up processes of regions which are latecomers in high technology sectors such as biotechnology.     

A Method for Quantitative Evaluation of the Effectiveness of tee Lubricants Used in Tablet Technology

Modern formulation bases the appropriate selection of excipients on technological determinations. Due to negative effects on mechanical and biopharmaceutical properties of tablets, the amount of lubricant to be used requires optimization. Lubricants are difficult to evaluate in terms of effectiveness. The number of references existing in literature on this topic substantiates the necessity still remaining in pharmaceutics for lubricant testing (1, 2, 3, 4, 5).