Experimental Measurement of Impact Pressures Delivered by Oral Water Irrigation Devices

Water irrigation devices (WID's) are widely used in homes and dental clinics across the country for oral hygiene. There have been several reported cases of tissue damage with the use of these devices. In the present investigation, two commercially available oral water irrigation devices were evaluated using engineering techniques. The impact thrusts delivered by these devices were measured at different control settings. Both of the tested commercial oral water irrigation devices were found to exert abnormally high thrust which could cause serious damage to the sulcular epithelium and the underlying tissues. These pressures are far in excess of the pressure intensity necessary to perform the cleaning action. Moreover, the existing designs using reciprocating pumps are unsafe and are potentially dangerous, particularly with small diameter tips.     

The influence of surface chemistry of nano-silica on microstructure,optical and mechanical properties of the nano-silica containing clear-coats

Different nano-silicas were incorporated in an automotive OEM clear-coat based on acrylic-melamine chemistry. The morphological characteristics of the heat-cured films were investigated using scanning electron microscopy. It was found that there is a close relationship between the interfacial interactions of binder-silica nano-particles and mechanical and optical properties of the baked films.     

Effect of fasting condition on multi-substrate carbon oxidation and nitrification system in an upflow packed-bed biofilm reactor

The performance of an upflow packed-bed biofilm reactor has been analyzed under multisubstrate limitation by considering simultaneous carbon oxidation and nitrification reactions. The fasting shock load of inlet methanol concentration has a much more pronounced effect on the response of the system compared to that of inlet NH₄⁺ -nitrogen concentration. The exit concentration of NH₄⁺ -nitrogen drops very close to zero, thereby showing essentially complete nitrification during methanol fasting condition. Further, the concentration profiles of oxygen within the biofilm show significant variation during methanol fasting and nonfasting conditions whereas during NH₄⁺ -nitrogen fasting conditions the oxygen concentration profile in the biofilm remains essentially unaffected.     

Influence of germination techniques on sprout yield,biosynthesis of ascorbic acid and cooking ability,in chickpea (Cicer arietinum L.)

Effects of germination time and illuminations on sprout yield, biosynthesis of ascorbic acid, cooking ability and moisture accumulation in chickpeas were significant (p ? 0.01). Green light had the highest promoting effect on the ascorbic acid level (40.59 mg/100 g) as compared to other illuminations but significantly reduced the sprout yield (188.6 g) as compared to dark, fluorescence and γ-rays illuminations with significantly high sprout yield (196 g) and imbibing moisture (51%). Cooking time was reduced by 43% due to γ-rays in un-soaked seed. Cooking time increased in all treated chickpea samples after 24 h germination and thereafter decreased significantly. Red light significantly increased the cooking time (68.44 min) followed by fluorescent (64.5 min), yellow (61.8 min) and green light (60.9 min). The results indicated that germination of chickpea under green light was an effective process in enhancing ascorbic acid content while dark, fluorescence and γ-rays were effective in promoting sprout growth and to some extent biosynthesis of ascorbic acid.     

Protect your intellectual property

An explanation is given of the four basic mechanisms for safeguarding intellectual property rights: copyrights, patent rights, trademarks, and trade secret laws. The extent to which they can be applied to computer hardware and software, and to what purpose and with what results, is explored     

On subsurface box-shaped lined tunnel under incident SH-wave propagation

In this paper, a half-plane time-domain boundary element method is applied to obtain the seismic ground response, including a subsurface box-shaped lined tunnel deployed in a linear homogenous elastic medium exposed to obliquely incident SH-waves. Only the boundary around the tunnel is required to be discretized. To prepare an appropriate model by quadratic elements, a double-node procedure is used to receive dual boundary fields at corners as well as change the direction of the normal vector. After encoding the method in a previously confirmed computer program, a numerical study is carried out to sensitize some effective parameters, including frequency content and incident wave angle for obtaining a surface response. The depth and impedance ratio of the lining are assumed to be unvaried. The responses are illustrated in the time and frequency domains as two/three-dimensional graphs. The results showed that subsurface openings with sharp corners distorted the propagation path of the anti-plane waves to achieve the critical states on the ground surface. The present approach can be proposed to civil engineers for preparing simple underground box-shaped models with angular boundaries.     

Optimal placement of steel plate shear walls for steel frames by bat algorithm

Layout optimization of steel frames with steel plate walls (SPWs) using a meta‐heuristic search algorithm is the main aim of the present study. SPWs are lateral load‐resisting systems, especially against earthquake excitation. These systems offer significant advantages in terms of cost, performance and ease of design compared with other systems. In this study, orthotropic membrane model is used to model the behaviour of steel plate shear walls. The newly developed bat algorithm, which is based on the echolocation behaviour of bats, is employed as the present study optimizer. Design variables of the optimization problem consist of the cross sections of beams and columns of the frame, the web plate thicknesses of SPWs and the placement of SPW in the frame. The bat algorithm performs suitable selection of sections from the AISC wide‐flange (W) shapes list. Strength constraints of the American Institute of Steel Construction Load and Resistance Factor Design and displacement constraints are checked during the optimization process. The results reveal the effectiveness of the proposed method for optimization of steel frames with SPWs. Copyright © 2014 John Wiley & Sons, Ltd.     

Hybrid organic/inorganic dendritic triblock copolymers: Synthesis,nanostructure characterization,and micellar behavior

A new class of amphiphilic dendritic ABA triblock copolymers, which is based on organic linear polyethylene oxide (PEO) and inorganic dendritic carbosiloxane (CSO) was synthesized. The strategy used in synthesizing these materials is based on divergent method using hydrosilylation‐alcoholysis cycles. The reaction conditions and structural features of dendrimers were analyzed by different physicochemical techniques such as: GPC, NMR, UV spectroscopy, DSC, and viscometry. The generational limit of dendrimer after the first generation, OSC‐D‐PEO‐D‐CSO, forced us to employ HSiCl₂CH₃ as branching reagent. Also further hydrosilylation of the third generation yielded an irregular structure species. Self‐assembling and morphological studies of first, OSC‐D‐PEO‐D‐CSO, and second, OSC‐D‐PEO‐D‐CSO, generations in aqueous medium were monitored by using fluorescence, TEM and DLS techniques. However, the dendritic block copolymer with third generation, OSC‐D‐PEO‐D‐CSO, could not be dispersed in aqueous phase. The diameters of denderitic micelles had a narrow distribution in the ranges of 69 and 88 nm, respectively. Although the micelles were stable even in first generation, partition equilibrium constants of pyrene and critical micelle concentration in both of dendritic micelles imply that the micellar behaviors of the supramolecules strongly depend on the hydrophobic block's size in which increasing generation effectively promoted the micelle formation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Design of electronic sections for nano-displacement measuring system

Noncontact displacement measurement is generally based on the interferometry method.In the semiconductor industry,a technique for measuring small features is required as circuit integration becomes denser and the wafer size becomes larger.An interferometric system known as a three-longitudinal-mode heterodyne interferometer (TLMI) is made of two main parts:optical setup and electronic sections.In the optical part,the base and measurement signals having 500-MHz frequency are produced,resulting from interfering three longitudinal modes.The secondary beat frequency to measure the displacement in the TLMI is about 300kHz.To extract the secondary beat frequency,wide-band amplifiers,double-balanced mixers (DBMs),band-pass filters (BPFs),and low-pass filters (LPFs) are used.In this paper,we design the integrated circuit of a super-heterodyne interferometer with total gain of 56.9dB in size of 1030μm×1030μm.