A summary of ring rolling technology—I. Recent trends in machines, processes and production lines

Ring rolling process is widely used in the production of seamless rings for automotive and aerospace industry. This paper presents a summary of the ring rolling technology: machine and process types; process considerations; and examples of ring rolling lines. In this technology survey, recent trends in ring rolling machines and processes are emphasized. This survey will be specially valuable for industry personnel engaged with the selection and implementation of ring rolling lines and process planning engineers working with ring rolling companies. It will also provide adequate background to researchers initiating research in the mechanics of the ring rolling process.     

Modifying of Cotton Fabric Surface with Nano-ZnO Multilayer Films by Layer-by-Layer Deposition Method

ZnO nanoparticle–based multilayer nanocomposite films were fabricated on cationized woven cotton fabrics via layer-by-layer molecular self-assembly technique. For cationic surface charge, cotton fabrics were pretreated with 2,3-epoxypropyltrimethylammonium chloride (EP3MAC) by pad-batch method. XPS and SEM were used to examine the deposited nano-ZnO multilayer films on the cotton fabrics. The nano-ZnO films deposited on cotton fabrics exhibited excellent antimicrobial activity against Staphylococcus aureus bacteria. The results also showed that the coated fabrics with nano-ZnO multilayer films enhanced the protection of cotton fabrics from UV radiation. Physical tests (tensile strength of weft and warp yarns, air permeability and whiteness values) were performed on the fabrics before and after the treatment with ZnO nanoparticles to evaluate the effect of layer-by-layer (LbL) process on cotton fabrics properties.     

Ultrasonic pre‐treatment of biological sludge: consequences for disintegration,anaerobic biodegradability,and filterability

BACKGROUND: Disintegration was developed as a pretreatment process for sludge to accelerate the digestion processes. Ultrasonic treatment may be a good alternative for sludge disintegration. In this study, different specific energy inputs ranged between 0 and 15 880 kJ kg^?1 and very low ultrasonic densities ranged between 0.04 and 0.1 W mL^?1 were applied to biological sludge for disintegration purposes. The potential for improving anaerobic digestion through ultrasonic pre‐treatment and the effect of ultrasonic pre‐treatment on the filterability characteristics of sludge were also investigated. RESULTS: 9690 kJ kg^?1 TS of supplied energy and very low power density of 0.09 Wm L^?1 are efficient for floc disintegration. For 9690 kJ kg^?1 TS, 44% higher methane production was achieved than with raw sludge as a result of biochemical methane potential assay. The supernatant characteristics of the sludge were also affected by the ultrasonic pre‐treatment. For 9690 kJ kg^?1 TS, the soluble chemical oxygen demand (SCOD), dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorus (TP) in the sludge supernatant increased by 340%, 860%, 716%, and 207.5%, respectively. CONCLUSION: Ultrasonic pre‐treatment is an effective method for biological sludge disintegration even at very low ultrasonic density levels. It leads to increased anaerobic biodegradability but deteriorates the filterability characteristics of biological sludge. Copyright © 2009 Society of Chemical Industry     

Catalytic combustion of carbon tetrachloride

The catalytic combustion of carbon tetrachloride (CCl4) by metal oxide catalysts coated on the monolith support was investigated. The prepared catalysts were tested at temperatures between 300 and 800 degrees C and at varying gas hourly space velocity (GHSV) values with an excess air ratio of 3100%. The catalyst, whose composition was 18% Cr2O3, 2% Ce2O3 and 80% gamma-Al2O3, was found to almost completely oxidize CCl4. The operating conditions proposed are 5702 h(-1) for GHSV, 3100% excess air and a temperature slightly higher than 800 degrees C. The reaction rate expression was found to be independent of oxygen partial pressure but strongly dependent on CCl4 partial pressure.     

Comparison of fully three-dimensional optical, normally conducting, and superconducting interconnections

Several approaches to three-dimensional integration of conventional electronic circuits have been pursued recently. To determine whether the advantages of optical interconnections are negated by these advances, we compare the limitations of fully three-dimensional systems interconnected with optical, normally conducting, repeatered normally conducting, and superconducting interconnections by showing how system-level parameters such as signal delay, bandwidth, and number of computing elements are related. In particular, we show that the duty ratio of pulses transmitted on terminated transmission lines is an important optimization parameter that can be used to trade off signal delay and bandwidth so as to optimize applicable measures of performance or cost, such as minimum message delay in parallel computation.     

Modular design of mechatronic systems with function modeling

This paper develops a modularization scheme based on the functional model of a system. The modularization approach makes use of the function–behavior–state (FBS) model of the system to derive the entity relations. The design structure matrix (DSM) is automatically constructed based on the FBS model. In this way, the tedious work of filling the DSM entries based on expert knowledge is avoided. The approach makes use of k-means clustering algorithm to allow the user to try different number of clusters in a fast way. The k-means clustering is adopted for DSM based modularization by defining a proper entity representation, relation measure and objective function. Two modularization schemes are performed, one based on the immediate relations and one on the deeper behavioral relations between the components. Considering the application on the shifting system of the Delft University of Technology (DUT) Formula Student car, the latter modularization resulted in more mechatronic behavior based modules, while the former resulted in modules based on mere disciplinary and spatial closeness.     

Instructional efficiency of integrated and separated text with animated presentations in computer-based science instruction

This study deals with the instructional efficiency of integrating text and animation into computer-based science instruction. The participants were 84 seventh-grade students in a private primary school in Istanbul. The efficiency of instruction was measured by mental effort and performance level of the learners. The results of the study showed that processing integrated text and animation format in computer-based science instruction requires less mental effort than the separated format, and that the performance of the students in the group with integrated presentation format group is higher than that of students in the group with separated presentation format. Instructional efficiency of the integrated presentation group was found to be higher than that of the separated presentation group. Finally, there was no difference between the two groups for instructional time.     

Cross-track transition location and transition parameter effects in heat-assisted magnetic recording

When conventional longitudinal and perpendicular magnetic recording architectures reach their well-known superparamagnetic limits, one candidate to break through the limit is heat-assisted magnetic recording (HAMR). In this paper, we investigate the effect of cross-track transition location and transition parameter (a-parameter) profiles in an HAMR system. Here, we apply microtrack modeling and the thermal Williams-Comstock model to longitudinal recording to determine the transition location and a-parameter profiles along the cross-track direction in the presence of a temperature profile. We then explore the effect of temperature on the isolated transition response of the system.     

MR findings of primary central nervous system lymphoma in a child. A case report

Huntington's disease is an autosomal dominant, inherited disorder that results in progressive degeneration of the basal ganglia (especially the neostriatal caudate nucleus and putamen) and other forebrain structures and is associated with a clinical profile of movement, cognitive and psychiatric impairments for which there is at present no effective therapy. Neuropathological, neurochemical and behavioral features of the disease can all be reproduced in experimental animals by local injection of excitotoxic or metabolic toxins into the neostriatum. All these features of the disease can be alleviated, at least in rats, by transplantation of embryonic striatal tissue into the degenerated striatum, which was the basis for commencing the first clinical trials of striatal transplantation in Huntington's patients. However, although rat striatal xenografts may temporarily reduce apomorphine-induced dyskinesias in monkeys, there has been no demonstration that allograft techniques that work well in rats translate effectively to the much larger differentiated striatum of primates. Here we demonstrate good survival, differentiation and integration of striatal allografts in the primate neostriatum, and recovery in a test of skilled motor performance. Long-term graft survival in primates indicates probable success for clinical transplants in Huntington's disease; in addition, our data suggest that graft placement has a direct influence on the pattern and extent of functional recovery.     

A Multi-step Virtual Screening Protocol for the Identification of Novel Non-acidic Microsomal Prostaglandin E2 Synthase-1 (mPGES-1) Inhibitors

Microsomal prostaglandin E₂ synthase-1 (mPGES-1) is a potential therapeutic target for the treatment of inflammatory diseases and certain types of cancer. To identify novel scaffolds for mPGES-1 inhibition, we applied a virtual screening (VS) protocol that comprises molecular docking, fingerprints-based clustering with diversity-based selection, protein–ligand interactions fingerprints, and molecular dynamics (MD) simulations with molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) calculations. The hits identified were carefully analyzed to ensure the selection of novel scaffolds that establish stable interactions with key residues in the mPGES-1 binding pocket and inhibit the catalytic activity of the enzyme. As a result, we discovered two promising chemotypes, 4-(2-chlorophenyl)-N-[(2-{[(propan-2-yl)sulfamoyl]methyl}phenyl)methyl]piperazine-1-carboxamide ( 6 ) and N-(4-methoxy-3-{[4-(6-methyl-1,3-benzothiazol-2-yl)phenyl]sulfamoyl}phenyl)acetamide ( 8 ), as non-acidic mPGES-1 inhibitors with IC₅₀ values of 1.2 and 1.3 μm , respectively. Minimal structural optimization of 8 resulted in three more compounds with promising improvements in inhibitory activity (IC₅₀: 0.3–0.6 μm ). The unprecedented chemical structures of 6 and 8 , which are amenable to further derivatization, reveal a new and attractive approach for the development of mPGES-1 inhibitors with potential anti-inflammatory and anticancer properties.