High sensitivity CMOS portable biosensor with flexible microfluidic integration

We perform correlation analysis between air temperature and surface brightness temperature over the Adelaide Central Business District and the surrounding parklands. The results indicate that three effective surface areas associated with three different mechanisms exist. They are the effective surface area with upward sensible heat transfer to heat up and maintain the air temperature, the effective surface area with downward sensible heat transfer to cool down the air, and the effective surface area related to very localized conditions (e.g., sky-view factors). The three mechanisms occur at different times of the day and result in different air temperature and surface temperature correlations. The first effective surface area exists in the daytime after the surface is heated up by solar radiation and can persist into the night, particularly in urban environments. The second effective area occurs in night-time when the surface has been cooled down sufficiently. The third effective area coexists with the second one and has a weaker correlation between the surface and air temperatures. It was also found that in an urban area, exclusion of roof pixels in the calculation of surface brightness temperature can increase the correlation between the surface and air temperatures in the middle of the night.

Stock–recruitment relationships (SRR) are used by many resource managers as a metric to evaluate stock reproductive potential and rebuilding capacity when harvested. This relationship is more evident in traditional finfish stock assessment models where larvae are frequently limited by the abundance of spawning adults, whereas invertebrate resources are much more confounding and often do not express a clear spawning SRR. Oysters in particular appear to be limited more strongly by post-settlement mortality as larvae are regularly demonstrated to be present in high abundance in response to timely shell plants; yet unexpectedly, a brood SRR appears to be present. Because of the unique life history of oysters which provide their own habitat through reef accretion, a posit is that the quantity and quality of such habitat are crucial determinants of recruitment to the stock, and habitat quality acts as a surrogate for brood stock in the stock–recruit relationship. An extensive dataset from Delaware Bay with a 65-y time series was analyzed to assess the relationship between available Crassostrea virginica natural reef materials and subsequent spat (<20 mm) settlement. Live oyster, box (dead and articulated valves), and cultch (disarticulated whole valves and shell fragments) surface areas were calculated for oyster reefs found in each of four regions oriented up-bay to down-bay within the survey area. Surface areas were standardized using RMA regressions which compared available surface area per shell type (live, box, and cultch) and the number of spat recruiting to each shell type. Standardized shell surface areas (i.e., effective surface areas) supported previous accounts that recruitment occurs with higher frequency on live oysters and boxes than cultch, and that excessive cultch availability does not always lead to successively high recruitment. Recruit density was found to not only vary by substrate type but also along a salinity gradient. In high salinity reefs, boxes function as high-quality recruitment substrate and cultch as low-quality substrate, whereas in low-salinity regions cultch is only slightly inferior to live and outcompetes box surfaces as a dominant recruitment substrate. Beverton–Holt and Ricker models were used to express the relationship between total effective surface area and recruitment; these models revealed that medium- and high-salinity regions produced higher recruitment rates than low-salinity reefs. Model steepness also increased at higher salinity, indicating that down-bay reefs responded more rapidly to a change in effective surface area than did up-bay reefs. Steepness was highest at the confluence of the medium-salinity and high-salinity reaches where larval supply provided by the down-bay drift of larvae from up-bay reefs was high, but salinity remained low enough to reduce biofouling and predation compared with the high-salinity region. Unlike the low-salinity region, the relationship between effective surface area and recruitment for the three down-bay regions exhibited compensation; recruitment did not rise linearly with effective surface area. In all four regions, however, recruitment was initiated on a reef at a nonzero effective surface area, an analogy to an Allee effect which existed in each case. By inference, reefs can die before effective surface area disappears.

There exists a growing demand on high performance variable filters for multi-function, multi-band wireless systems used in wide variety of applications. A variable capacitor with high capacitance ratio (CR) is one of the key devices to realize such controllable/reconfigurable filters. This paper reports the device structure, fabrication process, and the performance of a very high CR variable capacitor using pure water as dielectric material. The device holds two reservoir cells and was fabricated by microelectromechanical systems (MEMS) technology. It exhibited three digitally-stepped capacitances; varied from 0.93 pF to 32.9 pF (CR=35), then to 74.4 pF (CR=80) at 1 MHz by filling each of the cells with pure water. In order to confirm the electrical behavior for such a fluid MEMS capacitor, its microwave performance was evaluated. An equivalent RF circuit model with 9 elements has been introduced and the device performance was successfully simulated up to 4 GHz. It is also confirmed that the 3 step capacitance values stay effective in the same frequency range.

Double porous poly (Ɛ-caprolactone)/chitosan membrane scaffolds as niches for human mesenchymal stem cells

Mesh products are critical for successful long term surgical repair of many anatomic defects, including hernias and pelvic prolapse. Biocompatibility of polymeric mesh depends on the foreign body response- how the tissues react to physicochemical properties, including porosity and mesh ‘weight’. We postulate that effective surface area, the total filament area in contact with the tissues, is an important variable for long-term repair strength. We present a technique utilizing synchrotron x-radiation microComputed Tomography (microCT) to calculate the effective surface area of polymeric meshes. Six representative polypropylene-based hernia meshes, including composite meshes, were studied: Ethicon PROLENETM, Ethicon PROLENETMSoft Mesh, Ethicon PHYSIOMESHTM, Ethicon ULTRAPROTM, Atrium PROLITETM Mesh, and Bard® Soft Mesh. Ethicon PROLENETM , a heavy weight mesh, had the highest effective surface area at 6.44 cm2 cm−2 and Ethicon ULTRAPROTM, a composite light-weight mesh, had the lowest effective surface area at 0.62 cm2 cm−2. We conclude that this technique can reliably be used to further classify mesh, as manufacturers and surgeons continue to optimize the safety profile of these implants.

Environmentally responsible and minimal natural variation in electric power generation has been a goal of researchers for several decades. With the establishment of the electrical power generation potential from microalgae’s photosynthesis, several researchers revealed interesting microbial fuel cell configurations to improve the output of electrical parameters. However, little work is done to understand the electrical charge collected from photosynthesis. This article proposes a fuel cell-based electrochemical modeling of the micro-photosynthetic power cell. The model is developed, excluding significant analytical assumptions at stationary conditions. Due to the complexity of modeling the electron release from photosynthesis, the electron release reactions are substituted with a simpler redox coupler of similar electric potential to that of photosynthesis. The micro-photosynthetic power cell revealed that the electron collection rate does not directly correlate to the photosynthesis electron chain. It might remain constant for a specific electrical load. The peak power is obtained at a different operating loading than the internal resistance of the device. The experimental open circuit voltage ([Formula: see text]0.96[Formula: see text]V) and the peak power ([Formula: see text]0.18[Formula: see text]mW) are predicted accurately by this modeling approach. The results show that the fill factor remains constant with respect to several effective electrode surface areas. Based on this theoretical modeling, we believe that with optimized algal physiological state and micro-photosynthetic power cell’s effective surface area, this micro-photosynthetic power cell will be useful for application in low-power applications.

Effect of sound waves and inclination of membrane on the performance of the osmotic microbial fuel cell

Supercapacitors provide much higher power density than conventional batteries, while providing comparable energy density. Generally, porous materials like activated carbon, carbon nanotubes etc. are used to fabricate supercapacitor electrodes. A critical factor influencing the performance of the supercapacitor is the effective surface area of the porous electrode accessed by the electrolyte ions. The electrode micro-structure, the size of the electrolytic ions, etc. influence the effective surface area. It is hypothesized that due to the presence of air bubbles in the finer pores of the electrode, the electrolyte ions are unable to access the electrode surface easily. In the present work, the effect of vacuum impregnation of the electrode in improving the effective surface area is investigated. Activated carbon-based supercapacitor electrodes are fabricated and characterized by electrochemical techniques, before and after vacuum impregnation. Vacuum impregnation is seen to result in higher energy density but lower power density, and this is thought to be linked to easier access to deeper and finer pores on the electrode surface.

This study investigates the enhancement of the rate of evaporation from a nanoengineered solid surface using non-equilibrium molecular dynamics simulation. Four different types of surface modifications were introduced to examine the thermal transportation behavior. The surface modification includes: (1) transformation of surface wetting condition from hydrophobic to hydrophilic, (2) implementing nanostructures on the smooth surface, (3) cutting nano slots on the smooth surface and (4) introducing nano-level surface roughness. Evaporation behavior from the same effective surface area was also studied. The simulation domain consisted of three distinct zones: solid base wall made of copper, a few layers of liquid argon, and a vapor zone made of argon. All the nano-level surface modifications were introduced on the solid base surface. The few layers of liquid argon representing the liquid zone of the domain take heat from the solid surface and get evaporated. Outside this solid and liquid zone, there is argon vapor. The simulation began at the initial time t = 0 ns and then was allowed to reach equilibrium. Immediately after equilibrium was achieved on all three-phase systems, the temperature of the solid wall was raised to a higher value. In this way, thermal transportation from the solid wall to liquid argon was established. As the temperature of the solid wall was high enough, the liquid argon tended to evaporate. From the simulation results, it is observed that during the transformation from hydrophobic to hydrophilic conditions, enhancement of evaporation takes place due to the improvement of thermal transportation behavior. At the nanostructure surface, the active nucleation sites and effective surface area increase which results in evaporation enhancement. With nano slots and nano-level surface roughness, the rate of evaporation increases due to the increase of solid-liquid contact area and effective surface area.

This paper proposes a series of optimized scalable contact-capacitive radio frequency micro- electro-mechanical systems (RF MEMS) switches for millimeter wave applications. Due to the contact-capacitive topology, the ON-state and OFF-state of the switch can be designed separately to obtain smaller <inline-formula> <tex-math notation="LaTeX">$C_{ON}$ </tex-math></inline-formula> and larger <inline-formula> <tex-math notation="LaTeX">$C_{OFF}$ </tex-math></inline-formula>, which results in high capacitance ratio (<inline-formula> <tex-math notation="LaTeX">$C_{r}$ </tex-math></inline-formula>). The <inline-formula> <tex-math notation="LaTeX">$C_{ON}$ </tex-math></inline-formula> is defined by capacitance of the contacts, and it is optimized for low insertion loss (<inline-formula> <tex-math notation="LaTeX">$IL_{ON}$ </tex-math></inline-formula>). The <inline-formula> <tex-math notation="LaTeX">$C_{OFF}$ </tex-math></inline-formula> is defined by the metal-insulator-metal (MIM) capacitor, and it is designed for working band and scalable performance. The measurements of the fabricated devices show acceptable agreements with design and simulation. The optimized switches perform well with <inline-formula> <tex-math notation="LaTeX">$IL_{ON}$ </tex-math></inline-formula> better than 1.5dB and capacitive ratio about 124. The switches follow scaling rules from 20GHz to 110GHz. Linearity (IIP3) of the switches are tested to be higher than 60dBm, and calculated to be higher than 80dBm. Performances of the switch can be further improved and optimized in the future study.

Effective water surface mapping in macrophyte-covered reservoirs in NE Brazil based on TerraSAR-X time series

Numerical simulations and an experimental study for optimal design of a 1500 [formula omitted] water-tube condensing boiler

Preparation of large effective specific surface area reticulate porous ceramics by polymeric foam replication process using recoating technique

On the mechanisms associated with the chemical reactivity of Be in steam

In this study, systematic development of a portable sensor for the rapid detection of Escherichia coli (E. coli) and Exiguobacterium aurantiacum (E. aurantiacum) was reported. A conductive glass was utilized as a substrate and developed the electrode patterns on it. Trisodium citrate (TSC) and chitosan-stabilized gold nanoparticles (AuNPs) (CHI-AuNP-TSC) and chitosan-stabilized AuNPs (CHI-AuNP) were synthesized and utilized as a sensing interface. The morphology, crystallinity, optical properties, chemical structures, and surface properties of immobilized AuNPs on the sensing electrodes were investigated. The sensing performance of the fabricated sensor was evaluated by using an electrochemical method to observe the current changes in cyclic voltammetric responses. The CHI-AuNP-TSC electrode has higher sensitivity toward E. coli than CHI-AuNP with a limit of detection (LOD) of 1.07 CFU/mL. TSC in the AuNPs synthesis process played a vital role in the particle size, the interparticle spacing, the sensor’s effective surface area, and the presence of CHI around AuNPs, thus enhancing the sensing performance. Moreover, post-analysis of the fabricated sensor surface exhibited the sensor stability and the interaction between bacteria and the sensor surface. The sensing results showed a promising potential for rapid detection using a portable sensor for various water and food-borne pathogenic diseases.