bluuebunny/crossref_metadata_2025 huggingface dataset:
Attitudes of psychiatric nurses towards aggression: A polish study
Authors: Lickiewicz Jakub , Hughes Patricia Paulsen , Makara‐Studzinska Marta
Published: February 2021

Accessible Summary

What is known about the subject? (Scientific Rationale)

Mental health care in Poland lags behind that of many other countries, and coercive measures are used on a regular basis.

Scant research has been conducted in Poland regarding the treatment of psychiatric patients.

The perspectives of Polish psychiatric nurses towards aggression remain unknown.

What does this paper add to the existing knowledge?

The translated and validated Attitude Towards Aggression Scale (ATAS) in Polish will serve as an instrument that gauges Polish nurses’ attitudes towards aggression. The Polish nurses have unenlightened and negative attitude towards aggression.

What are the implications for practice?

There is now an instrument in Polish by which we can gauge the attitudes of mental health nurses, which must precede any educational efforts. Polish nurses showed more restrictive and antiquated attitudes about patient violence than nurses in some other parts of the world. With a shift to more positive attitudes, the use of coercion could be reduced, resulting in improved patient care.

Introduction

In Poland, the mode and site of patient treatment have changed little in the past 75 years, despite therapeutic advances worldwide. There is limited information regarding attitudes of nurses towards aggression in psychiatric settings in Poland, nor has there been an instrument in Polish to measure it.

Aim

To translate and validate the Attitudes Towards Aggression Scale (ATAS) for use in Poland, and to assess the attitudes of three groups of nursing personnel towards aggression.

Method

We surveyed 980 psychiatric and general nurses as well as nursing students. We translated the ATAS into Polish, and validated it using exploratory factor analysis.

Results

The Polish version of the ATAS showed good psychometric properties. We found that Polish nurses perceived patient aggression extremely negatively.

Discussion

Polish nurses perceive aggression as destructive, negative and not to be tolerated, leading to use of restraints. Among the three groups, psychiatric nurses showed the most negative attitude towards aggression. Thus, education is needed for preservice and inservice nurses alike to address this issue.

What this study adds to existing evidence

We now have a validated instrument to assess nurses’ attitudes about aggression. We also know that Polish nurses have exceedingly negative attitudes towards aggression.

Implications for Practice

The Polish version of ATAS was found valid and reliable. Therefore, we can now measure the attitudes of Polish nurses towards aggression, which was not possible previously. The baseline data provide a starting point from which to determine effects of educational efforts.
Clinical characteristics and histology of cholecystectomised dogs with nongravity‐dependent biliary sludge: 16 cases (2014‐2019)
Authors: Viljoen A. D. , Tamborini A. , Watson P. J. , Bexfield N. H.
Published: February 2021

Objectives

To report the available histology, biochemistry and clinical progression of dogs without classic overt biliary tract signs that underwent cholecystectomy for nongravity‐dependent biliary sludge.

Materials and Methods

Case series of client‐owned dogs for which a cholecystectomy was performed for nongravity‐dependent biliary sludge. In six dogs, for which nongravity‐dependent biliary sludge filled less than half of gall bladder volume, gall bladder ejection fractions were measured. Available histology, biochemistry, presenting clinical signs and post‐surgical clinical progression were reported.

Results

Sixteen dogs were included in this retrospective case series. No dogs met the histological criteria for gall bladder mucocoeles or had histological evidence of primary hepatitis or cholangitis. Biochemistry was normal for 11 dogs. Hypercholesterolaemia was not noted in any dog. Twelve dogs had cholecystitis (11 lymphoplasmacytic, one neutrophilic) and nine dogs had biliary mucosal hyperplasia. Thirteen dogs had enteritis (12 lymphoplasmacytic, one eosinophilic) and nine dogs had reactive hepatitis (eight lymphoplasmacytic, one neutrophilic). All six dogs with nongravity‐dependent biliary sludge that filled less than half of gall bladder volume had sub‐optimal gall bladder function. Presenting clinical signs, including diurnal inappetence in the morning and exercise intolerance, resolved in 86% (12/14) of dogs after cholecystectomy and clinical improvement was noted in 81% (13/16) of dogs overall.

Clinical Significance

Duodenal inflammation could potentially impact gall bladder dysmotility in dogs with nongravity‐dependent biliary sludge. Furthermore, diurnal inappetence in the morning and exercise intolerance could indicate symptomatic gall bladder disease in dogs with NDBS and can potentially precede more obvious systemic clinical signs associated with gall bladder mucocoeles.
Insomnia symptoms and subclinical myocardial injury: Data from the Nord‐Trøndelag Health (HUNT) study
Authors: Sigurdardottir Fjola D. , Lyngbakken Magnus N. , Hveem Kristian , Hrubos Strøm Harald , Røsjø Helge , Redline Susan , Omland Torbjørn
Published: February 2021

Insomnia symptoms are associated with increased risk of heart failure (HF) and cardiovascular (CV) mortality. We hypothesised that insomnia symptoms are cross‐sectionally associated with increased cardiac troponin I (cTnI), a biomarker of subclinical myocardial injury, and that phenotyping by insomnia symptoms and cTnI enhances longitudinal risk stratification in the general population. In a population‐based study, cTnI was measured in 8,398 participants (median age 49 years, 55% women), who had answered questionnaires regarding insomnia symptoms. Association between cTnI and insomnia symptoms was assessed by linear regression analysis for each response category of a sleep questionnaire. Insomnia symptoms were defined as having difficulty falling asleep almost every night, difficulty maintaining sleep almost every night, and/or non‐restorative sleep once a week or more. The primary outcome measure was a composite endpoint of CV mortality or first admission for HF. In all, 844 participants reported insomnia symptoms, 585 (69%) were women. Those with insomnia symptoms had marginally, but significantly higher median cTnI than those without insomnia symptoms, (median [interquartile range] 3.4 [2.4–5.2] ng/L versus 3.2 [2.2–4.9] ng/L; p = .014), but there was no association between any insomnia symptom and cTnI in unadjusted linear regression models (β 0.06, 95% confidence interval [CI] −0.01 to 0.12). In adjusted analyses, participants with insomnia symptoms and increased cTnI were at increased risk of the composite endpoint (hazard ratio 1.71, 95% CI 1.04–2.79) compared to participants with insomnia symptoms and low cTnI. In the general population, insomnia symptoms are not associated with biochemical evidence of subclinical myocardial injury.
Releasates of riboflavin/UV‐treated platelets: Microvesicles suppress cytokine‐mediated endothelial cell migration/proliferation
Authors: Schubert Peter , Culibrk Luka , Culibrk Brankica , Conway Edward M. , Goodrich Raymond P. , Devine Dana V.
Published: February 2021

Background

Accelerated development of the platelet (PLT) storage lesion upon pathogen inactivation (PI) is associated with the release of proteins from granules and platelet microvesicles (PMVs). Whether PI treatments alter the interaction between PLT factors and the vessel endothelium is of interest in understanding the risk profile of these technologies.

Study Design and Methods

In a pool‐and‐split study, one platelet concentrate (PC) was treated with riboflavin/UV (RF/UV) light, while the other one was kept as an untreated control. Releasates and PMV‐depleted releasates were prepared by differential centrifugation steps on days 0, 1, 5, and 7 of storage. Cytokine/chemokine release following PI treatment was analyzed by an antibody array, and results were verified by the enzyme‐linked immunosorbent assay. PMVs were enumerated by CD41 labeling and flow cytometry. Wound scratch assays were performed using cultured Ea.hy926 cells exposed to the differently prepared releasates. Effects of releasates on the phosphorylation levels of kinases ERK and p38 expressed by endothelial cells were analyzed by immunoblot.

Results

Cytokine/chemokine assays identified a 2‐fold increase in epidermal growth factor released from PCs treated with RF/UV light compared with control. PMV count increased ~100‐fold following PI treatment. Unmodified releasates and PMV‐depleted releasates displayed different contributions to the kinetics of endothelial cell wound closure. This observation was associated with an increased ERK versus unaltered p38 activation in the endothelial cells.

Conclusion

This study identified an inhibitory impact of PMVs on endothelial cell migration/proliferation upon stimulation by released cytokines and PMVs from PLTs treated with RF/UV light for endothelial cell wound closure.
Adults’ experience of living with multimorbidity: a qualitative systematic review protocol
Authors: Whitehead Lisa , Palamara Peter , Browning Shannon , Ferris Jessica
Published: February 2021

Objective:

The objective of the review is to synthesize the qualitative research literature on the experiences of adults living with multimorbidity.

Introduction:

Persons living with two or more chronic health conditions, known as multimorbidity, is a global health problem in countries of all income levels. Multimorbidity presents an ever-increasing resource and financial burden for health care systems and similarly challenges those living with multiple health conditions because of the complexity of their health and treatment requirements. Overall, persons with multimorbid conditions experience a high risk of mortality and a lower quality of life. Understanding the adult experience of multimorbidity is important for creating and implementing health care that meets the needs of individuals living with the burden of multiple chronic health conditions.

Inclusion criteria:

The systematic review will include published peer-reviewed and unpublished English-language studies from 2000 to 2020 that provide qualitative evidence of adults’ (18+ years of age) experiences of living with multimorbidity.

Methods:

CINAHL with full text, Cochrane, MEDLINE, Embase, PsycINFO, Consumer Health Database, Scopus, and ScienceDirect journals and books will be searched. Reference lists of included studies will also be cross-checked with search outcomes to identify additional studies. Sources of gray literature will also be searched for unpublished studies. The critical appraisal of selected studies and the extraction of data will be independently undertaken by two reviewers using JBI methods. The findings will be pooled using meta-aggregation to produce comprehensive synthesized findings. A ConQual Summary of Findings will also be presented.

Systematic review registration number:

PROSPERO CRD42020152038
Hablar en público en la universidad: un manual para desenvolverse ante una audiencia
Authors: Moya Barreto John
Published: February 2021

Hablar en público de forma apropiada es una habilidad con la que no todo el mundo cuenta. Sin embargo, hay ciertos ámbitos de la actividad humana que, para determinados momentos, exigen un dominio de ella, como lo son el académico, el organizacional o el social. Y si bien esta habilidad puede cultivarse en cualquier etapa de la vida, el periodo más propicio para ello es el paso por la universidad, no solo por la formación integral que esta brinda, sino también por el vínculo afectivo que existe entre el estudiante y su programa académico, sea de pregrado o posgrado. En vista de lo anterior, Hablar en público en la universidad tiene como propósito, por medio de los consejos prácticos que ofrece, guiar a los estudiantes universitarios en los procesos de preparación y ejecución de sus discursos orales, de modo que estos sean amenos, estéticos, claros, contundentes y efectivos.
Design Aspect of Creep
Authors: Bailey R. W.
Published: February 2021

This paper is an abstract of a manuscript submitted by Mr. Bailey at the request of the Plasticity Committee of the Applied Mechanics Division through its chairman, Dr. Nadai. The paper is also an abridgment of Mr. Bailey’s paper read before the Institution of Mechanical Engineers, London, November 22, 1935. The purpose of this abstract is to indicate the wide range of topics treated fully in the original paper and to give a useful and adequate summary of this pioneer work by Mr. Bailey.

In many cases, because of lack of space, the bases of the author’s conclusions are not discussed in this abstract nor are the mathematical derivations included. The reader interested in these details should consult the London paper. Footnotes have been added to this abstract mentioning references which are readily available and which will supplement and illuminate this abbreviated treatment. Comprehensive and somewhat different abstracts of the original London paper have also appeared in “Engineering,” November 29 and December 13, 1935, and in “The Engineer,” December 6, 1935.
Deflection of Beams of Varying Cross Section
Authors: Hetényi Miklós
Published: February 2021

This paper calls attention to a new method of dealing with deflections of beams, the cross sections of which vary by steps. It is shown that the effect of this variation on the shape of the deflection curve can be represented by a properly chosen force system acting on a beam of uniform cross section. There is no approximation involved in this substitution, whereby the original problem is reduced to one of computing deflections of beams of constant cross section.
The Leakage of Gases Through Narrow Channels
Authors: Egli Adolf
Published: February 2021

In this paper a rational theory is developed as a basis for calculating the flow of gases (compressible fluids) through narrow channels. For the most important case the solution of the general flow equation is given in graphical form which shows the relation between mass flow, pressure drop, and channel resistance.

Tests of the leakage of air and steam through the narrow clearance between a valve stem and bushing afford a practical demonstration of the use of the theory. Formulas are derived for the calculation of the leakage of gases through reamed bushings on ground stems. Expressions for the leakage of liquids (incompressible fluids) are obtained as special cases of the gas formulas.
Flow Through Granular Media
Authors: Bakhmeteff Boris A. , Feodoroff N. V.
Published: February 2021

Ever since Darcy’s (1) basic work on the mechanics of filtration, flow through porous media has been the object of repeated research. Numerous and most valuable data on filtration coefficients have been gathered (2), the approach in recent years having been broadened by invoking the principle of dynamic similitude (3). So far, however, no general picture has been disclosed, such for example as made available for pipes by Osborne Reynolds and his successors. Systematic research was initiated accordingly at the fluid-mechanics laboratory of Columbia University with the object of possibly obtaining a comprehensive view of the phenomenon as a whole. This paper summarizes the results of the first series of experiments, which deal with flow through media composed of uniform spherical bodies, for which lead shot varying in diameter from 0.0377 in. to 0.361 in. was used.

The device used permitted resistance slopes over 7 : 1, and the Reynolds’ characteristics were extended to the unprecedented range of nearby 1.8 × 103. Under such conditions the whole series of the successive flow forms became evident. The initial Darcy type of flow with resistance proportional to the first power of the velocity was superseded by a zone where losses rapidly grew on an increasing power of the velocity Un, until in the higher ranges once more an apparently stable pattern with a constant exponent n = 1.8 was reached.

A simple method based on dimensional considerations and which takes into account the varying porosities was used to reduce experimental data to a unified basis. In terms of a proper Reynolds characteristic, the generalized resistance coefficient in a quadratic formula presented itself in the form of a unified continuous outline. The possible mechanism of resistance in the different flow forms is discussed in the condensed survey of the dynamics of the case preceding the description of the experiments. The unwarranted analogy with laminar and turbulent flow in pipes is substituted by an interpretation invoking a parallel with the Stokes type of flow and with the customary “form” resistance of spheres. At the close a comprehensive expression is given to the Darcy filtration coefficient taking account of the porosity and the viscosity of the fluid, with only one dimensionless empirical parameter, the numerical value of which assumedly is a constant for a certain shape.
Practical Aspects of Turbine Cylinder Joints
Authors: Campbell C. B.
Published: February 2021

Existing American standards for steel flanged fittings satisfactorily cover the requirements for round pipe joints in the several pressure classifications, providing the type of flange is properly chosen for the particular service. The design of nongasketed, high-pressure, and high-temperature joints for steam-turbine cylinders is quite another problem, and an understanding of the principles underlying the design of steam-tight joints is necessary to its successful solution. It is the purpose of this paper to bring out the important considerations affecting such flanged joints and to note the general methods adopted for their analysis by the company with which the writer is associated.
The Effect of the Speed of Stretching and the Rate of Loading on the Yielding of Mild Steel
Authors: Davis E. A.
Published: February 2021

The phenomena occurring at the upper and lower yield point in mild steel is not yet fully understood. This paper is an attempt to study some of these phenomena and to correlate them with the facts already known about the first yielding of this unique material.

In order to investigate the rate of loading on the yielding of mild steel a machine was designed in which the amount of increase in load per unit time could be held constant regardless of the rate of strain. Results of tests are presented in which the rate of loading for separate tests was changed by a maximum ratio of 1 to 21,000. The effect of rate of loading was studied on four different shapes of test specimens.

Factors affecting the initial yielding of mild steel and their influence on the shape of the stress-strain diagram are discussed. These factors include the effect of the speed of deformation and of stress concentration upon the stress at which yielding takes place. The manner in which localized yielding affects the stress distribution in the bar and changes the actual strain rate is also described. The constant-load-rate type of test such as presented here is compared with the ordinary constantstrain-rate type of test. Various shapes of stress-strain diagrams that have been obtained in practice are explained in terms of the factors previously mentioned.
Reheat Factors for Expansions of Superheated and Wet Steam
Authors: Thatcher Charles G.
Published: February 2021

For superheated-steam expansions, charts show the reheat factors plotted against the ratio of P1/P2 up to a maximum value of 50 for this ratio. The probabilities are that these values of reheat factor are accurate to within one part in a thousand.

The effect of stage efficiency is considered and results presented. Within the superheat region all stage efficiencies are considered to be constant.

Wet-region values are worked out by the step-by-step method, and are presented entirely separate from those for the superheat region. Here also the effect of stage efficiency is included, as well as the effect of decreasing stage efficiency due to increasing moisture content in the expanding steam. The lack of uniformity in practice on this latter issue is pointed out and a suggestion made which should lead to clearer understanding. Moisture removal, which is prevalent in modern turbines, causes discontinuity in the condition curve, and a suggestion is made for the construction of the curve for such a case.

Finally, there is given a method of calculating a condition curve for an expansion from any point in the superheat region and terminating in the wet region. It was found impractical to present a chart of reheat factors for such expansions.
Steady Oscillations of Systems With Nonlinear and Unsymmetrical Elasticity
Authors: Rauscher Manfred
Published: February 2021

Steady forced oscillations are reduced to free undamped oscillations of the same amplitude. The reduction is accomplished by changing the excitation from a time function F(t) into a space function F(x) through the assumption that x and t are related as in a free motion. By combining F(x) with the elastic restoring force E(x), a new effective E(x) is obtained, to which there corresponds a new “free” motion, which in turn furnishes a second approximation for the relation between x and t, and hence a new function F(x). A new effective E(x) and a new free motion are then found; and the cycle is repeated until the relation between x and t ceases to change. The frequency of the forced motion at the assumed amplitude is then known. In general, the process converges rapidly. The accuracy can be checked at any stage of the work. A general criterion of the stability of the motions is offered.
Pool Boiling of R514A, R1224 yd(Z), and R1336mzz(E) on a Reentrant Cavity Surface
Authors: Kedzierski M. A. , Lin L.
Published: February 2021

This paper quantifies the pool boiling performance of R514A, R1224 yd(Z), and R1336mzz(E) on a flattened, horizontal Turbo-ESP surface for air-conditioning applications for heat fluxes between roughly 10 kWm−2 and 100 kWm−2. R514A, R1224 yd(Z), and R1336mzz(E) are replacements for R123 and R245fa. All of these replacement refrigerants had measured boiling heat fluxes that were larger than that for R123 for most heat fluxes. For example, for heat fluxes between 10 kWm−2 and 80 kWm−2, R514A, R1224 yd(Z), and R1336mzz(E) exhibited average heat fluxes that were 30%, 57%, and 13% larger than that for R123 for a saturation temperature of 277.6 K. For the same comparison done at a saturation temperature of 298.2 K, the average heat flux for R514A was roughly 43% larger than that for R123. A pool boiling model, that was previously developed for pure and mixed refrigerants on the Turbo-ESP surface, was compared to the measured boiling performance. The model predicted the measured superheats of the mixed refrigerants and the single-component refrigerants to within ± 0.7 K and ± 0.45 K, respectively.
An Interactive CAPP Kernel Based on a Blackboard System Architecture
Authors: Kruth Jean-Pierre , Van Zeir Geert , Detand Jan
Published: February 2021

This paper describes the ideas and developments that lead to a new Computer Aided Process Planning (CAPP) approach : a blackboard-style, interactive CAPP system, in which the human process planner is assisted by expert modules, each capable of performing a process planning task. At all times, the human operator has full control over all planning activities. An important reasoning mechanism, that is inevitably linked with the interactive CAPP kernel, is opportunistic process planning. The implementation of this mechanism in an automatic feature based CAPP system will also be elaborated in this paper.
Automatic Assembly Sequence Planning With Fuzzy Graph Representation and Genetic Search
Authors: Sebaaly Milad Fares , Fujimoto Hideo
Published: February 2021

The Assembly Sequence Planning (ASP) problem is a complicated task that is still performed manually in most advanced industries. It consists of finding the best or optimal sequence to assemble a certain product, given its CAD design. Although it seems simple at first, its complexity drastically increases with increasing numbers of product parts, so that complexity is very high for most actual industrial products. Many ASP planners have been developed by researchers to automate this problem, but most of these are not practical and general enough to deal with actual industrial products. One of the main disadvantages is that these planners perform an extensive search of all possible sequences in order to choose the optimal solution. Another rather important disadvantage is that most generated sequences are linear, i.e. one part is assembled at a time, or have very simplistic plan generation. Sebaaly and Fujimoto (1996) introduced a novel approach to overcome the first disadvantage by applying genetic algorithms. A best-so-far solution is reached without searching the complete set of possible candidates, and the search is performed on a sequence population basis rather than on parts basis. However, this method is restricted to generating linear sequences only. This paper addresses improving that approach to generate more general solutions, by introducing an assembly fuzzy graph representation that can represent both linear and non-linear sequences. The sequences search space is thus extended to include all feasible combinations of linear and non-linear assembly operations. From the set of assembly rules and constraints of a certain product, a set of assembly stages is defined, such that every assembly operation is assigned to a certain stage according to its position in the set of constraints. A fuzzy relation is then defined as a grade of connectivity between product parts. Based on this relation, a fuzzy graph connecting the product parts is generated. This graph can represent both linear and non-linear sequences. After that, the algorithm of Sebaaly and Fujimoto (1996) is improved to deal with the new search space. The new modified algorithm is applied to a practical example from industry where the applicability and capability of the new algorithm are confirmed.
Tool Operation Based Operation Force Teaching: Extracting Force Control Strategy From Human’s Work in Virtual Environment
Authors: Tateno Toshitake , Igoshi Masanori
Published: February 2021

This paper deals with a virtual environment which is used for extracting expert’s knowledge of work and transferring the work information to a worker. The worker is either a human or a robot. Tool based work representation is convenient for both human and robots to use the data. Tool operation is also convenient to construct a force feedback system in a virtual environment. The data recorded in the virtual environment is saved as work examples in a database, and used by a worker when he wants to refer to the samples. In the virtual environment an expert shows what he wants to do. It’s not important to get a detail amount of data. The most important objective of the virtual environment is to get the expert’s knowledge on the work through the force. In this paper we propose a new virtual environment which is based on qualitative simulation. We call it Virtual Mental Space (VMS) because human mental models are said to be qualitative models about the physical world. Interactions between a human and the VMS provides explanations of what he wants to do, and make it possible to get a force which he wants to stress. The tool operation is used conveniently again to smooth the interaction.
Integration of Aesthetic Intents to CAD Systems
Authors: Pham Binh
Published: February 2021

We propose a scheme to categorise aesthetic intents, and analyse the required characteristics for viable representations of these intents. A theoretical framework is then presented to allow aesthetic intents to be specified and achieved during designing stage. This framework may be used as guidelines for implementing and integrating aesthetic intents to CAD systems.
Feature Extraction Techniques by Optimal Volume Decomposition
Authors: Dong Jian , Vijayan Sreedharan
Published: February 2021

The elements of Computer-Aided Manufacturing, do not make full use of the part description stored in a CAD model because it exists in terms of low-level faces, edges and vertices or primitive volumes related to the manufacturing planning task. Consequently manufacturing planning still depends upon human expertise and input to interpret the part definition according to manufacturing needs.

Feature-based technology is becoming an important tool to resolve this and other related problems. One approach is to design the part using Features directly. Another approach is Manufacturing Feature Extraction and Recognition. Manufacturing Feature Extraction consists of searching for the part description, recognizing cavity features, extracting those features as solid volumes of material to be removed. Feature Recognition involves raising this information to the level of part features which can be read by a process planning program. The feature extraction can be called optimal if the manufacturing cost of the component using those features can be minimized. An optimized feature extraction technique using two powerful optimization methods viz., Simulated Annealing and Genetic Algorithm is presented in this paper. This work has relevance in the areas of CAD/CAM linking, process planning and manufacturability assessment.
Augmented Convex Decomposition Using Incremental Update for Recognition of Form Features
Authors: Parienté Frédéric , Kim Yong Se
Published: February 2021

Alternating Sum of Volumes with Partitioning (ASVP) decomposition is a volumetric representation of a part obtained from its boundary representation that organizes faces of the part in an outside-in hierarchy. ASVP decomposition combines Alternating Sum of Volumes (ASV) decomposition, using convex hulls and set difference operations, and remedial partitioning, using cutting operations and concave edges. A Form Feature Decomposition (FFD) which can serve as a central feature representation for various applications is obtained from ASVP decomposition. The incremental update of convex decomposition is achieved by exploiting its hierarchical structure. For a connected incremental design change, the active components that only need to be updated are localized in a subtree of the decomposition tree called active subtree. Then, the new decomposition is obtained by only updating the active subtree in the old decomposition. In this paper, we present a new decomposition, called Augmented Alternating Sum of Volumes with Partitioning (AASVP) decomposition, that is incrementally constructed using ASV incremental update as a local operation on a decomposition tree. AASVP provides an improved feature recognition capability as it localizes the effect of the change in the decomposition tree, avoids excessive remedial partitioning and catches the designer’s intent in feature editing. AASVP differs from ASVP at the remedial-partitioning nodes by partitioning less. The current remedial partitioning method could be improved such that AASVP decomposition can be constructed directly from the solid model.
Fire Modeling
Authors: Lilley David G.
Published: February 2021

The mathematical modeling approach to simulating fire development in a multi-room building complements the experimental approach and/or post-fire on-site investigations. Fire simulation models provide estimates of the amount and temperature of the smoke layer produced, the evolution of toxic gases, and the amount of time available from the onset of fire for the safe departure of occupants. Results can be used to determine the key features of the fire evolution and the corresponding danger to occupants. Studies of this type help to validate or deny the suggested fire scenario and witness statements. Fire modeling thus helps to discriminate between alternative fire scenarios by evaluating the consequences and comparing them with observations.
On the Thermal Decomposition of Solid Wastes
Authors: Missoum A. , Gupta A. K. , Chen J. , Keating Eugene L.
Published: February 2021

Experimental and theoretical studies have been conducted on the thermal destruction behavior of 100% cellulose and mixture of 90% cellulose-10% polyethylene (C13H8O7) in a laboratory scale facility. A series of pyrolysis and oxidative pyrolysis (pyrolysis followed by air or oxygen addition) tests were performed. Temperature was varied from 600 to 1500K. Data provides the effect of temperature, air addition and chemical composition of the surrogate solid waste on the emissions of NOx, CO, CO2 and unburnt hydrocarbons (HC). Thermal destruction behavior of the surrogate waste is qualitatively observed to be enhanced with the progressive increase in temperature which also results in increased reduction of the material volume. Numerical calculations using equilibrium conditions are used to describe the experimentally observed trends for the thermal decomposition behavior of these materials. Analysis of the data reveals that composition of the waste as well as conditions under which the process of thermal destruction takes place (i.e., temperature, excess air or oxygen enrichment) and process type (combustion or pyrolysis) have significant influence on the product gas composition. The results also show significant effect of air enrichment on the distribution of species during pyrolysis and oxidative pyrolysis. These results reveal that controlled thermal destruction involving pyrolysis followed by combustion provides attractive benefits of high thermal destruction efficiency and low pollutants emission. This information can assist in developing strategies for the design and operation of thermal destruction facility.
Eccentricity Effect of a Coolant Inlet Labyrinth Seal for Turbine Wheelspace Cavities
Authors: Guo Zhou , Rhode David
Published: February 2021

The computed effects of an eccentric rotor on the mass and heat ingress through a gas turbine wheelspace rim seal have been studied using a 3-D Navier-Stokes computer code with a recent three-scale k-∈ turbulence model and orthogonal body-fitted coordinates. All compressibility and thermal/momentum interaction effects were included, as actual engine temperatures, pressures, Reynolds numbers, etc were used. The combined effects of an eccentric coolant inlet seal, in conjunction with an eccentric rim seal, were compared with the case of an eccentirc rim seal alone. It was found that heat and mass ingress into the cavity through the rim seal are not affected by the coolant/purge inlet seal eccentricity, whereas they are strongly affected by the eccentricity of the rim seal. The total heat flux through the rim seal, due to mass ingress thermal transport and turbulent heat diffusion, was examined in order to better understand this wheelspace cavity heating mechanism. It was found that the turbulent heat diffusion flux is a significant percentage of the total heat flux at small rotor eccentricity, whereas it is entirely negligible at large eccentricity.
Minimum Requisite of Mathematica for Engineering Analyses
Authors: Pao Y. C.
Published: February 2021

Three aspects of Mathematica applications are addressed. The first is to use the symbolic language for simple mathematical operations, such as matrix algebra, root finding, spline curve-fit, and Runge-Kutta integration. The second is about graphic applications such as drawing curves, bar graph, labeling, and up to three-dimensional, hidden-line plotting. The third and most important aspect is to use the Mathematica C-type commands to define user’s problems which the students must master in order to apply Mathematica effectively.
Elastic Stress Concentration Factors (Kt) by Stress Gradient Method Using FEA
Authors: Garg Ajay , Tetambe Ravi
Published: February 2021

The elastic stress concentration factor, Kt, is critical in determining the life of machines, especially in the case of notched components experiencing high cycle fatigue. This Kt is defined as the ratio of the maximum stress (σmax) at the notch to the nominal stress (σnom) in the region away from the notch effect. For simple geometries such as, plate with a hole, calculation of Kt from either closed form solution or from making simple but valid assumptions is possible [1,2]. However, for complex machine components such data is usually not available in the literature. Using Kt values from the simple geometries may lead to either over or under estimation of the real Kt for such complex geometries. Such error can then further lead to a substandard product or a product which is overdesigned and expensive.

Present paper outlines a methodology for computing reasonably accurate elastic stress concentration factor, Kt, using finite element analysis (FEA) tool. The maximum stress (σmax) is readily available from the finite element analysis. The nominal stress (σnom) near the stress concentration is however can not be directly extracted from the FEA results. A novel approach of estimating reasonably accurate σnom is presented in this paper. This approach is based on selecting the correct path at the stress concentration region, post processing the stress and the stress gradient results along that path and identifying the cut of point where stress concentration effect begins to take place. This methodology is first validated using two examples with known Kt and later applied to a real world problem.
Transient Response Analysis of Geometrically Nonlinear Laminated Composite Shell Structures
Authors: To Cho W. S. , Wang Bin
Published: February 2021

The investigation reported in this paper is concerned with the prediction of geometrically large nonlinear responses of laminated composite shell structures under transient excitations by employing the hybrid strain based flat triangular laminated composite shell finite element presented here. Large deformation of finite strain and finite rotation are considered. The finite element has eighteen degrees-of-freedom which encompass the important drilling degree-of-freedom at every node. It is hinged on the first order shear deformable lamination theory. Various laminated composite shell structures have been studied and for brevity only two are presented here. It is concluded that the element proposed is very accurate and efficient. Shear locking has not appeared in the results obtained thus far. There is no zero energy mode detected in the problems studied. For nonlinear dynamic response computations, the full structural system has to be considered if accurate results are required.
Using Object-Oriented Frame Language for Realizing Discrete Event Simulation
Authors: Dong Ming , Cha Jianzhong , E Mingcheng
Published: February 2021

In this paper, we realize knowledge-based discrete event simulation model’s representation, reasoning and implementation by means of object-oriented(OO) frame language. Firstly, a classes library of simulation models is built by using the OO frame language. And then, behaviours of simulation models can be generated by inference engines reasoning about knowledge base. Lastly, activity cycle diagrams can be used to construct simulation network logic models by connecting the components classes of simulation models. This kind of knowledge-based simulation models can effectively solve the modeling problems of complex and ill-structure systems.
General Equations of a Helical Spring With a Cup Damper and Static Verification
Authors: Wu Ming Hsun , Ho Jing Yuan , Hsu Wensyang
Published: February 2021

The general equations of motion of the helical spring with a cup damper are derived by considering the dilation of the damper and varying pitch angle of the helical spring. These dynamic equations are simplified to show to agree with other models proposed by previous investigators.

The static solution of equations and the static force-displacement relation are also derived. The extra stiffness due to the damper dilation considered in the force-displacement relation is the first such modeling in this area. A method to predict the coil clash length in compressing spring is present and verified with experimental data. Finally, the simulation results of the static force-displacement relation are shown to agree with the experiment data well.
Temperature Field Analysis of the Main Bearing of Cold Rolling Mill by Finite Element Method
Authors: Ye Xiao Qiao , Chen Zhong Ping , Lee Yuan Ke , Yu Jun
Published: February 2021

The temperature distribution of a 4-row tapered roller bearing in 1700mm cold rolling mill is studied by finite element analysis. A mathematical model of heat transfer and the boundary conditions of the bearing system are given. The results of temperature measurement in the bearing show a satisfactory agreement with the calculated results.
Parting Line Formation by Slicing a Trimmed Surface Model
Authors: Wong T. , Tan S. T. , Sze W. S.
Published: February 2021

The parting line on a product affects the final layout of the mould blocks and hence the manufacturing efficiency. The increased usage of free-form surfaces in product design increases the burden of computer aided parting line and parting surface determination. Previous proposed algorithms may not be sufficient to deal with such situation since most of them were originally designed to deal with products having planar surfaces or simple curved surfaces. A new algorithm is proposed to deal with such situation. The algorithm adopted a recursive uneven slicing on a trimmed surface model. The method provides a quick and efficient way of locating the parting line of a product.
Updating Finite Element Model of Combined Structures on the Basis of Dynamic Test Results
Authors: Xin Chen , Ye Qin , Xiguang Yuan , Ping Zhang , Jian Sun
Published: February 2021

According to the real situation, a new method of updating the finite element model (FEM) of a combined structure step by step is proposed in this paper. It is assumed that there are two types of error when establishing the FEMs. One of them results from the simplifications, in fact, it is severe for complicated structures, which usually assume many simplifications; the other is from the process of identifying structural joint parameters. For this reason, it is recommended that the FEM should be established in two stages. At the first stage, the local physical parameters relating with the simplifications are corrected by using the dynamic test data of the corresponding substructures. Then, the structural joint parameters that link the substructures are corrected by the dynamic test data of the combined structure as a whole. The updating formula is presented and proved, and its algorithm is also described. And the experimental results show that the efficiency and accuracy of the proposed method are quite satisfactory.
Using CIMOSA and Stochastic Time Petri Nets for Behaviour Modeling of CIM Systems
Authors: Dong Ming , Cha Jianzhong
Published: February 2021

The integrated model of an enterprise can be built by making use of the CIMOSA modeling framework and modeling language. The behaviour analysis of the CIMOSA enterprise model can be made by the sets of procedural rules. In order to make further performance analysis of the CIMOSA enterprise model, this paper presents a systematic approach to transform the CIMOSA enterprise model into a equivalent stochastic Petri net model. The systematic approach is a hybrid Petri nets synthesis technology which integrates the “bottom-up” and “top-down” modeling approaches. The resulting Petri net obtained from this approach preserve the same qualitative properties of its original Petri net.
Strategic Genetic Algorithms to Obtain Multiple Acceptable Design
Authors: Arakawa Masao , Yamakawa Hiroshi
Published: February 2021

In the design process, it would be much better to give designers more and more acceptable and reasonable design candidates to derive their preferences to meet requirements of multiple high performances. In this paper, we will propose a new method, to give such acceptable design candidates based on genetic algorithms (GAs) with considering something like strategy for adaptation. GAs are search algorithms based on the mechanics of natural selection and natural genetics. Yet, they are no simple random walk but they efficiently exploit historical information to speculate on new search points with expected improved performance. Thus, we expect in GAs to give multiple acceptable and near optimum design candidates just like so many species in natural living things. However, in simple GAs, after specific number of generations, their populations become near one or two specific local optimum solutions. (Hoping for including global optimum solution.) In order to obtain multiple acceptable solutions, we need to perform GAs processes by keeping variations in characters of individuals. The proposed method tries to find multiple acceptable solutions by considering strategy for adaptation into GAs processes, which are food chain, strategy of foraging, death strategy and strategy of reproduction. As a numerical example, we apply the proposed method to simple multi-objective optimization and demonstrate its efficiencies.
Optimal Hierarchical Decomposition Synthesis Using Integer Programming
Authors: Krishnamachari Ramprasad S. , Papalambros Panos Y.
Published: February 2021

Decomposition synthesis in optimal design is the process of creating an optimal design model by selecting objectives and constraints so that it can be directly partitioned into an appropriate decomposed form. Such synthesis results are not unique since there may be many partitions that satisfy the decomposition requirements. Introducing suitable criteria an optimal decomposition synthesis process can be defined in a manner analogous to optimal partitioning formulations. The article presents an integer programming formulation and solution techniques for synthesizing hierarchically decomposed optimal design problems. Examples for designing a pressure vessel, an automotive caliper disc brake and a speed reducer are also presented.
Frictional Impact Analysis in Constrained Multibody Systems
Authors: Ahmed Shakil , Lankarani Hamid M. , Pereira Manual F. O. S.
Published: February 2021

Analysis of impact problem in the presence of any tangential component of impact velocity requires a friction model capable of correct detection of the impact modes such as sliding, sticking, and reverse sliding. A survery of literature has shown that studies on the impact analysis of multibody systems have either been limited to the direct impact type with only a normal component of impact velocity (no frictional effect) or the ones that include friction have shown energy gains in the results due to the inherent problem in the use of Newton’s hypothesis. This paper presents a formulation for the analysis of impact problems with friction in constrained multibody mechanical systems. The formulation recognizes the correct mode of impact, i.e., sliding, sticking, and reverse sliding. The Poisson’s hypothesis is used for the definition of the coefficient of restitution, and thus the energy gains inherent with the use of Newton’s hypothesis are avoided. The formulation is developed by using a canonical form of the system equation of motion using joint coordinates and joint momenta. The use of canonical formulation is a natural way of balancing the momenta for impact problems. The joint coordinates reduces the equations of motion to a minimal set, and eliminate the complications arised from the kinematic constraint equations. The canonical form of equations are solved for the change in joint momenta using Routh’s graphical method. The velocity jumps are then calculated balancing the accumulated momenta of the system during the impact process. The impact cases are classified based on the pre-impact positions and velocities, and mass properties of the impacting systems. Analytical expressions for normal and tangential impulse are derived for each impact case. The classical problem of impact of a falling rod with the ground (a single object impact) is solved with the developed formulation, and the results are compared and verified by the solution from other studies. Another classical problem of a double pendulum striking the ground (a multibody impact) is also solved. The results obtained for the double pendulum problem confirms that the energy gain in impact analysis can be avoided by considering the correct mode of impact and using Poisson’s instead of Newton’s hypothesis.