Engineering Commons^™

Scanning Electron Microscopy Of The Osteoclast-Bone Interface In Vivo, H. Zhou, R. Chernecky, J. E. Davies

Cells and Materials

Rat femoral bones were studied by scanning electron microscopy to demonstrate the morphology of osteoclast- bone matrix interfacial relationships. Two general morphological types of actively resorbing osteoclasts were observed . One cell type was approximately ovoid with highly fimbriated borders, fully attached and closely adapted to the resorption surface. The ruffled border of such cells was composed of a number of individual filopodia which were of uniform , regular shape and approximately 2-3 μm in length and 150 nm in diameter. They were found to penetrate the bone matrix to a depth of 1 μm and interdigitated with the surrounding …

Attachment Kinetics And Differentiations Of Osteoblasts On Different Biomaterials, U. Meyer, D. H. Szulczewski, K Moller, H. Heide, D. B. Jones

Cells and Materials

Primary bovine osteoblast cell cultures were used to study the response of osteoblasts ton three different biomaterials, ionomeric cement (IC), tri-calcium phosphate poly-L-lactic acid composite foil (TCP) and poly-L-lactate-polycitric acid composite foil (PLA). The cells which grew on the materials produced all typical bone matrix proteins and were osteoblast-Iike as shown by immuno-staining. Analysis of the cell attachment kinetics revealed significant differences within the first 7 hours between the various materials. The best rate of cell attachment was found on the IC surface, followed by the TCP and then the PLA surface. The kinetics of attach ment appeared to be …

Cell-Degradation Of Calcium Phosphate Ceramics, P. Frayssinet, N. Rouquet, F. Tourenne, J. Fages, D. Hardy, G. Bonel

Cells and Materials

Calcium phosphate ceramics are used in bone surgery under different forms: dense or porous ceramic s as bone substitute, thin ceramic coatings on metallic implants as an osseointegration enhancer. Their degradation depends on their physico-chemical properties and particularly on their chemical composition. Natural calcium phosphates of bone are degraded by mononuclear or multinuclear cells and the extracellular matrix induces the differentiation of the degrading-cells. Hydroxyapatite, which is one of the most used calcium phosphates , is known as a low degradation material. However, the histological analysis of implanted HA-materials both in animals and in humans showed that a cellular degradation …

Analysis Of The Bony Interface With Various Types Of Hydroxyapatite In Vitro, J. D. De Bruijn, J. S. Flach, K. De Groot, C. A. Van Blitterswijk, J. E. Davies

Cells and Materials

Rat bone marrow cells, capable of forming bonelike tissue, were cultured on three types of plasma sprayed hydroxyapatite that differed in degree of crystallinity from 15%, 43% to 69%. The interface between the mineralized extracellular matrix and the hydroxyapatite was studied with scanning and transmission electron microscopy. At the onset of bone formation, calcium and phosphorous-rich afibrillar globules, with a diameter varying from 0.2 to 0.8 μm, were produced and deposited onto the different substrata. These globules subsequently fused to form a homogeneous layer to which collagen fibres became anchored. Individual globules could be distinguished on the non-degrading 69 % …

Intravital Microscopic Evidence That Polylactide-Polyglycolide (Plga) Delays Neo-Osteogenesis And Neo-Angiogenesis In Healing Bone, H. Winet, J. O. Hollinger

Cells and Materials

The bone chamber implant (BCI) has allowed monitoring a healing bone defect as well as the effect of an eroding implant on the healing process. The BCI is a useful tool and intravital microscopy a valuable technique for obtaining quantitative data chronicling osseous wound healing. The physiological parameters that form the initial data base documenting healing are neo-osteogenesis and neo-angiogenesis. This review compares and characterizes osseous wound healing in a BCI loaded with an erodible copolymer, PLGA (polylactide-polyglycolide). To determine if a statistically significant deviation from normal healing had occurred, the results were compared with present and historical controls. In …

Bs News

Building Services Engineering

No abstract provided.

Multiple Sample Cryostat For The Determination Of Superconductor Properties, G. Burnside, Roger M. Hawk, Paul C. Mcleod

Journal of the Arkansas Academy of Science

Cryostats which are currently used to characterize the properties of superconductors between 4 K and 100 K are primarily single sample devices. The purpose of this paper is to present an instrument design which can hold up to five (5) one cm. diameter samples at a stable temperature (+ /-0.1K) within the above range specified while measurements of the sample properties are made.

Sputter Deposition And Thallination Of Ti-Ba-Ca-Cu-O Superconducting Thin Films, T. H. Dhayagude, S. S. Ang, W. D. Brown

Journal of the Arkansas Academy of Science

Thallination techniques used for the fabrication of sputter-deposited TI2Ba2CaCu 2Ox and TI2Ba2Ca2Cu3Ox superconducting thin films were investigated. Differences in elemental composition of precursor Ba-Ca-Cu-O sputtering targets were found to yield different superconducting phases. Thallination conditions which yielded transition temperatures as high as 122 K for samples annealed in air are described. Finally, reactive ion etching of films using a mixture of chlorine and argon gases is discussed.

Computer Model For Predicting Aids Among Intravenous Drug Users, Daniel Berleant, R. Ron Goforth, Jun Yuan

Journal of the Arkansas Academy of Science

Intravenous drug abuse (IVDA) is an important cause of HIV transmission. Computer simulation is one way to understand and predict the spread of HIV infection among IVDAs. We design and simulate HIV infection among IVDAs and the impact of AIDS on this community, and thereby predict future IVDA population, HIV levels, AIDS levels, and AIDS deaths in this group. The HIV to AIDS, and AIDS to Death latencies are described by probability density functions (PDFs) in this model. Factors such as the recruit, quit, and normal death rate of IVDAs, are considered, as well as the infection and removal rates …

Semi-Insulating Polysilicon Hetero- And Isotype Junctions On Silicon, R. M. Ranade, S. S. Ang, W. D. Brown

Journal of the Arkansas Academy of Science

The effects of nitrogen trifluorideinthe gas stream during deposition of semi-insulating polysilicon (SIPOS) on the electrical characteristics of undoped (SIPSO)/p-Si, and n+-SIPOS/n-Si isotype junctions were investigated. The current-voltage characteristics of undoped SIPOS/p-Si heterojunctions exhibit a strong dependence on the oxygen content of the SIPOS film and depart from a hyperbolic sine behavior as the refractive index of the SIPOS increases.. The addition of nitrogen trifluoride decreases the current density of these undoped SIPOS/p-Si heterojunctions due presumably to the oxidation/hydrolysis of SiF species intoSiO2. The n+-SIPOS formed a rectifying isotype junction o n-Si. The forward current voltage characteristics exhibit two distinct …

Economic Impacts Of Noxious Facilities: Incorporating The Effects Of Risk Aversion, Leslie A. Nieves

RISK: Health, Safety & Environment (1990-2002)

The author suggests an integrative approach for projecting economic impacts of facilities that elicit public Risk aversion. She incorporates both economic stimulus effects and perception-based effects of facilities on the host area economy. Empirical findings are compared and an impact estimation framework is suggested for integrating psychometric and econometric techniques.

Bs News

Building Services Engineering

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.

Ole Miss Engineer 1992

Ole Miss Engineer

No abstract provided.

Book Review, Peter C. Christensen

RISK: Health, Safety & Environment (1990-2002)

Review of: MARY R. ENGLISH, SITING LOW-LEVEL RADIOACTIVE WASTE DISPOSAL FACILITIES: THE PUBLIC POLICY DILEMMA. (Quorum Books 1992) [278 pp.], Appendices, index, introduction, references. LC-91-42774; ISBN 0-89930-560-1. [$49.95 cloth. One Madison Avenue, New York NY 10010.]

Risk Estimation And Expert Judgment: The Case Of Yucca Mountain, Kristin Shrader-Frechette

RISK: Health, Safety & Environment (1990-2002)

Professor Shrader-Frechette discusses factors responsible for acute disagreement between the federal government and Nevada citizens over potential Risks at Yucca Mountain and focuses on the use of expert judgment, concluding that some of them appear to exemplify "bad science." That aside, she argues that 1,000 year predictions cannot be made from current knowledge of geology or, e.g., institutional behavior and concludes that permanent disposal of radioactive waste is currently impossible.

Bs News

Building Services Engineering

No abstract provided.

34th Rocky Mountain Conference On Applied Spectroscopy

Rocky Mountain Conference on Magnetic Resonance

Program and registration information for the 34th annual meeting of the Rocky Mountain Conference on Applied Spectroscopy, co-sponsored by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 2-6, 1992.

Bs News

Building Services Engineering

No abstract provided.

Optimization Of Dispersed Flor Pond For Bacterial Removal, Mayo A. W

Tanzania Journal of Engineering and Technology (TJET)

The design of waste stabilization ponds is seldom done with consideration of optimum pond dimensions. The analysis of pond dimensions within practical limits in dispersed flow ponds on the basis of minimum cost for the predetermined bacterial remova) ef ficiency, with the aid of computer is presented. The data collected in the pilot and full scale waste stabilization ponds at the University of Dar es Salaam Was used as input to the computer program. The results shows that pond configuration and climatic conditions which have influence on bacterial mortality rate have a re:narkable influence on pond cost

The Performance Of A Horizontal Flow Roughing Filter/Slow Sand Filter Water Treatment Plant In Tanzania, Mbwette T. A

Tanzania Journal of Engineering and Technology (TJET)

The performance of a water treatment plant comprising of the Horizontal f Iow Roughing F i Iter (HRF) / Slow Sand Filter (SSF) System was evaluated by monitoring the water quality of the inlet water and the plant filtrates for a Improper operational procedures and period of two months. the absence of adequate maintenance of the plant was found to have resulted to relatively Iow removal efficiency. This subsequently improved as a result of plant rehabilitation and introduction of new operational procedures and became comparable to the performance of HRE/SSF plants documented in literature. For example, as a result of …

Theoretical And Experimental Study Of Inlet Manifold Pressure Profiles Using Compensated Transducers, P Mtui

Tanzania Journal of Engineering and Technology (TJET)

Computer simulation and experimental findings on single cylinder four-stroke cycle engine were done with a view of getting more realistic inlet manifold pressures. Since there is a direct relationship between the inlet pressure profiles and the volumetric efficiency of the engine, then there is a possibility of utilizing the knowledge of these profiles to enhance better engine air flow characteristics and hence improvement of engine performance.

The simulation program is based on hometropic process with constant specific heats where the results were validated using experimental findings of the engine with varying engine speeds.

Experimental results are obtained by measuring manifold …

Hydrodynamic Stability Of The Breakwater Extension At Rrviksand, Norway, Alfonse Dubi

Tanzania Journal of Engineering and Technology (TJET)

The fishing port of Årviksand in Norway, which is situated on an open coast, is artificially harboured by breakwaters. The northern and southern breakwaters which were built in 1930—ies and 1950—ies respecti vely have been on several occasions damaged by heavy storms. This resul ted in the need for further protection by extending the northern breakwater. This paper describes one of the hydrodynamic tests on the breakwater extension. The breakwater, with a berm breakwater concept design, is subjected to the joint probability of sea level elevation and wave heights (in other 'fatigue" test). words , It is found that cover …

Control System Design Program Based On Cascade Compensation, Fredrick Ishengoma

Tanzania Journal of Engineering and Technology (TJET)

CAD is becoming more widely accepted in the design and analysis of control systems. A program has been developed for analyzing single-input single-output linear time-invariant control system. The application of the progranl for frequency domain design of cascaded phase lead and phase lag coinpensators is briefly discussed. Two examples to illustrate the program are presented.

Evaluation Of Wind Data Records To Predict Extreme Extreme Wind Speeds In Tanzania, L Lwambuka

Tanzania Journal of Engineering and Technology (TJET)

The progress made towards evaluation of local wind data records to pred ict extreme values of wind speeds in Tanzania is being presented . Records of wind data, stored continuously since 18 years, have been compiled and statistically processed. Extreme value theory of Fisher —Tippet Type I has been fitted into the data to abstract extreme values of wind speeds for locations at which the wind data records were obtained. A reliable wind map of Tanzania containing basic wind speeds at 18 locations across the country has been produced. The basic wind speeds are being recommended for des ign against …

Statistcal Analysis Of Some Parameteres Of Sliver Preparation On It`S Quality, Rizk El-Bealy Associ.Prof

Mansoura Engineering Journal

In the present work, the experimental design technique was used to study the influence of some variables at the processing prior to spinning on the variation of card sliver quality. The variables considerd to be affecting the card sliver quality are as follow: blowroom lines/chute feed arrangement, carding machines were used throughout, days of production and cotton fibers. A statistical analysis were made of the sliver parameters, its size, count variations neps per gram and sliver irregularity, using three factor analysis of variance. The results declared that the chosen variables and interactions had a large influence on the sliver quality …

Book Review, Allan M. Wheatcraft

RISK: Health, Safety & Environment (1990-2002)

Review of the following: LEONARD EVANS, TRAFFIC SAFETY AND THE DRIVER. (Van Nostrand Reinhold 1991) [404 pp.] About the author, author index, figures, notes, preface, subject index, tables. LC 90-44233, ISBN 0-4421-00163-0. [Cloth $51.95. P.O.B. 668, Florence KY 41022-0668.]

Bs News

Building Services Engineering

No abstract provided.

Ole Miss Engineer 1992

Ole Miss Engineer

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.