Inertial MEMS Sensors

In this work, novel electrostatic micro-electro-mechanical system (MEMS) sensor and sensors are introduced and demonstrated. First, a novel bifurcation-based MEMS ethanol vapor sensor is demonstrated. In contrast to traditional gas sensors that measure in analog mode (quantify) gas concentration, this sensor does not quantify the gas concentration. Rather, it detects its gas concentration in binary mode, reporting (1) for concentrations above a preset threshold and (0) for concentrations below the threshold. The sensing mechanism exploits the qualitative difference between the sensor state before and after the static pull-in bifurcation in electrostatic MEMS. The transition between these states is the bifurcation used in detection. A driving circuit with a resolution of 1 mV was used to drive the sensor at a point close to the pull-in limit to achieve maximum sensitivity. The sensor was able to detect concentrations as low as 5 ppm of ethanol vapor in dry nitrogen, equivalent to a detectable mass of 165 pg. Gas detection was verified electrically and optically through a detection circuit and a CCD camera, respectively. Second, a novel tunable MEMS magnetic field sensor is demonstrated in this work. It measures torsional vibrations excited via Lorentz force. The sensor sensitivity and dynamic range can be tuned by varying a bias voltage. Experimental demonstration shows that the sensor sensitivity can be changed from 0.436 (mm/s)/mT at 6 V bias to 0.87 (mm/s)/mT at 1 V bias. Unlike most commercial magnetic sensors, this magnetic sensor achieves a higher bandwidth (182 kHz) and a tunable sensitivity adjustable on-the-fly.1 yea

Electrostatic MEMS Bifurcation Sensors

We report experimental evidence of a new instability in electrostatic sensors, dubbed quasi-static pull-in, in two types of micro-sensors operating in ambient air. We find that the underlying mechanism and features of this instability are distinct from those characterizing hitherto known static and dynamic pull-in instabilities. Specifically, the mechanism instigating quasi-static pull-in is a global Shilnikov homoclinic bifurcation where a slow-varying waveform drives the sensor periodically through a saddle-node bifurcation. Based on these findings, we propose a new taxonomy of pull-in instabilities in electrostatic sensors. Experimental evidence of nonlinear chaotic behaviors were observed in an electrostatic MEMS sensor. Period doubling bifurcation (P-2), period three (P-3), and period six (P-6) were observed. A new class of intermittency subsequent to homoclinic bifurcation in addition to the traditional intermittencies of type-I and type-II were demonstrated. Quasiperiodicity and homoclinic tangles leading to chaos were also reported. All of these nonlinear phenomena instigate either banded chaos or full chaos and both are observed in this work. Based on our knowledge, this is the first observation such chaotic behaviors in electrostatic MEMS sensors. All of the experimental observations have been measured optically via a laser Doppler-vibrometer (LDV) in ambient pressure. Also, a new class of intermittencies was found in the oscillations of an electrostatic sensor. These intermittencies involve a dynamic system spending irregular time intervals in the vicinity of the ghost of an orbit before undergoing bursts that are arrested by landing on a larger attractor. Re-injection into the vicinity of the ghost orbit is noise induced. As a control parameter is increased, switching intermittency of type-I leads to a stable periodic orbit, whereas switching intermittency of type-II leads to a chaotic attractor. These significant findings in nonlinear dynamic were used to develop novel MEMS sensors. An electrostatic MEMS gas sensor is demonstrated. It employs a dynamic-bifurcation detection technique. In contrast to traditional gas or chemical sensors that measure (quantify) the concentration of an analyte in analog mode, this class of sensors does not seek to quantify the concentration. Rather, it detects the analyte's concentration in binary mode, reporting ON-state (1) for concentrations above a preset threshold and OFF-state (0) for concentrations below the threshold. The sensing mechanism exploits the qualitative difference between the sensor state before and after the dynamic pull-in bifurcation. Experimental demonstration was carried out using a laser-Doppler vibrometer to measure the sensor response before and after detection. The sensor was able to detect ethanol vapor concentrations as 100\,ppb in dry nitrogen. A closed-form expression for the sensitivity of dynamic bifurcation sensors was derived. It captured the dependence of sensitivity on the sensor dimensions, material properties, and electrostatic field. An analog dynamic bifurcation mass sensor is developed to demonstrate a sensing mechanism that exploits a quantitative change in the sensor state before and after depositing added mass. A polymeric material was deposited on the top surface of the sensor plate to represent added mass. A variation in the frequency and current amplitude were utilized to demarcate the added mass optically and electrically. A chemical sensor was also developed to detect mercury in deionized-water in a fashion of analog detection. A polymeric sensing material that has high selectivity to mercury was utilized to captured mercury molecules in water. The sensor was submerged completely in water with a pre-defined flow-rate. The sensor was excited electrostatically. A variation in the frequency response due to added mass was measured electrically using a lock-in amplifier. A frequency-shift was observed while releasing the mercury to the water

Local delivery to malignant brain tumors: potential biomaterial-based therapeutic/adjuvant strategies

Glioblastoma (GBM) is the most aggressive malignant brain tumor and is associated with a very poor prognosis. The standard treatment for newly diagnosed patients involves total tumor surgical resection (if possible), plus irradiation and adjuvant chemotherapy. Despite treatment, the prognosis is still poor, and the tumor often recurs within two centimeters of the original tumor. A promising approach to improving the efficacy of GBM therapeutics is to utilize biomaterials to deliver them locally at the tumor site. Local delivery to GBM offers several advantages over systemic administration, such as bypassing the blood-brain barrier and increasing the bioavailability of the therapeutic at the tumor site without causing systemic toxicity. Local delivery may also combat tumor recurrence by maintaining sufficient drug concentrations at and surrounding the original tumor area. Herein, we critically appraised the literature on local delivery systems based within the following categories: polymer-based implantable devices, polymeric injectable systems, and hydrogel drug delivery systems. We also discussed the negative effect of hypoxia on treatment strategies and how one might utilize local implantation of oxygen-generating biomaterials as an adjuvant to enhance current therapeutic strategies. © 2021 The Royal Society of Chemistry

Enabling Development; design of a the Single Seat Wintec Electric Vehicle.(SSWEV)

The research project is related to the single seat three-wheel electric vehicle. Due to the high consumption of the oil in New Zealand (NZ) which have a direct impact on the economy, the authorities are now looking for an alternative source to power the vehicles and revolutionize the transport industry. There is another motive behind the development of electric vehicle (EV) which is linked with the environmental conditions of the country. The Internal Combustion Engine (ICE) vehicles increase the air pollution in the country and due to which the global warming has become a serious issue. To reduce the global warming effect and air pollution the electric vehicles have become a strong candidate or choice for the transportation. This project covers the electric vehicle in three parts: the Road Legal Status of EV in New Zealand, the Battery Electric System(BES), and Vehicle Design. There are some limitations which are associated with electric vehicles such as legislation does not encourage the people to purchase an electric vehicle, and the manufacturers are still interested in ICE vehicles. The research project proposes the desired policy for the EV in New Zealand. The possible design of the EV is proposed which is modeled in SolidWorks. Furthermore, the entire battery electric system and its management is included in the report which describes the proposed Battery electric system for single-seat electric vehicle. The primary goal in developing the battery electric system of the EV was to ensure that it has long driving range. The current EV are struggling to achieve the long driving range. The design selected for the EV is Reverse-trike. The unique features include the shifting of the centre of mass of the more extensive position. This design provides more stability and traction to the vehicle as the weight shift is towards the front wheels of the car

A Study for Sustainable IT: Management Effects of On-Premises and On-Demand IT on Carbon Intensity

Reducing the level of carbon intensity – i.e., the level of carbon emission – is an important issue in cooperate IT management. Drawing upon the belief-action-outcome (BAO) framework, this study examines the impact of two different IT resources – i.e., on-premises IT (OPIT) and on-demand IT (ODIT) – on a firm’s carbon intensity. Also, we examine the moderating impact of green management strategies – i.e., environmental board oversight and environmental management incentives – on the effect of OPIT and ODIT on a firm’s carbon intensity. Using panel data with a sample of 3074 observations collected from 864 firms from 2016 to 2019, we find that OPIT usage is positively associated with carbon intensity, whereas ODIT usage is negatively associated with carbon intensity. In addition, we find that, while environmental board oversight mitigates the positive direct impact of OPIT on carbon intensity, environmental management incentives reinforce the negative direct impact of ODIT on carbon intensity

Local delivery to malignant brain tumors: potential biomaterial-based therapeutic/adjuvant strategies

Glioblastoma (GBM) is the most aggressive malignant brain tumor and is associated with a very poor prognosis. The standard treatment for newly diagnosed patients involves total tumor surgical resection (if possible), plus irradiation and adjuvant chemotherapy. Despite treatment, the prognosis is still poor, and the tumor often recurs within two centimeters of the original tumor. A promising approach to improving the efficacy of GBM therapeutics is to utilize biomaterials to deliver them locally at the tumor site. Local delivery to GBM offers several advantages over systemic administration, such as bypassing the blood–brain barrier and increasing the bioavailability of the therapeutic at the tumor site without causing systemic toxicity. Local delivery may also combat tumor recurrence by maintaining sufficient drug concentrations at and surrounding the original tumor area. Herein, we critically appraised the literature on local delivery systems based within the following categories: polymer-based implantable devices, polymeric injectable systems, and hydrogel drug delivery systems. We also discussed the negative effect of hypoxia on treatment strategies and how one might utilize local implantation of oxygen-generating biomaterials as an adjuvant to enhance current therapeutic strategies

PHENOS: a high-throughput and flexible tool for microorganism growth phenotyping on solid media

Abstract Background Microbial arrays, with a large number of different strains on a single plate printed with robotic precision, underpin an increasing number of genetic and genomic approaches. These include Synthetic Genetic Array analysis, high-throughput Quantitative Trait Loci (QTL) analysis and 2-hybrid techniques. Measuring the growth of individual colonies within these arrays is an essential part of many of these techniques but is useful for any work with arrays. Measurement is typically done using intermittent imagery fed into complex image analysis software, which is not especially accurate and is challenging to use effectively. We have developed a simple and fast alternative technique that uses a pinning robot and a commonplace microplate reader to continuously measure the thickness of colonies growing on solid agar, complemented by a technique for normalizing the amount of cells initially printed to each spot of the array in the first place. We have developed software to automate the process of combining multiple sets of readings, subtracting agar absorbance, and visualizing colony thickness changes in a number of informative ways. Results The “PHENOS” pipeline (PHENotyping On Solid media), optimized for Saccharomyces yeasts, produces highly reproducible growth curves and is particularly sensitive to low-level growth. We have empirically determined a formula to estimate colony cell count from an absorbance measurement, and shown this to be comparable with estimates from measurements in liquid. We have also validated the technique by reproducing the results of an earlier QTL study done with conventional liquid phenotyping, and found PHENOS to be considerably more sensitive. Conclusions “PHENOS” is a cost effective and reliable high-throughput technique for quantifying growth of yeast arrays, and is likely to be equally very useful for a range of other types of microbial arrays. A detailed guide to the pipeline and software is provided with the installation files at https://github.com/gact/phenos

Public awareness and understanding of stem cell treatments available in Saudi Arabia and their trust in hospitals and research centers involved in stem cell research—a cross sectional study

IntroductionAlthough stem cell research and therapeutic applications hold great promise for medical advancements, and have rapidly progressed globally, there remains a lack of genuine public awareness of the status of this subject in Saudi Arabia. Successful integration of stem cell therapy into healthcare relies on public awareness, understanding, and trust. Therefore, we aimed in this cross-sectional study to assess the public’s knowledge, awareness, trust, support, participation, and confidence in stem cell treatments and centers involved in it.Materials and methodsA voluntary questionnaire of 20 questions was distributed randomly via social media outlets.ResultsThree thousand five hundred eighty four individuals participated in the survey, with approximately half of them falling within the age range of 35–50 years (46.71%). Majority of the participants, 90.71%, would like to know more about stem cell therapy and more than half of the participants (56.94%) were unfamiliar with the idea, and a comparable proportion (50.41%) expressed concerns about the safety of stem cell therapy. A lower level of awareness, indicated by a score of 5, was evenly distributed across all age groups and genders. However, regardless of gender, older participants—especially those 50 years of age or older—tended to report higher levels of confidence, trust, and support than participants in other age groups. Moreover, trust, support, participation, and confidence score for those attained high school or less was statistically significantly lower than those attained master’s or PhD degree. Of the participants, 33.57% had either received stem cell therapy themselves or known someone who had; about 24.07% of them reported that it was a cosmetic type of treatment.ConclusionThe study emphasizes the persistent need for awareness and educational initiatives to minimize the lack of public awareness and understanding of approved stem cell treatments in Saudi Arabia. It advocates for increased education, transparency, and communication to bridge knowledge gaps and enhance public trust to ensure the understanding of successful treatment

Physicochemical characterization of natural hydroxyapatite/ cellulose composite

The natural hydroxyapatite (HAp, activated at different temperatures)/ cellulose composites have been prepared by usingsonication method to improve the physical properties of the cellulose fibre. The molecular level interaction and the physicalproperties of the hydroxyapatite/cellulose composite are examined using FTIR, X-ray diffraction, SEM, and thermalanalysis. The absorption bands at around 660 cm1 confirm the O–P–O bending vibration in the HAp/cellulose composites.There is a difference in the d-spacing of the HAp /cellulose composite, indicating that the HAp is reactive towards cellulose.SEM indicates that HAp could penetrate the cellulose network structure to form particles that is helpful to improve themechanical properties of the cellulose. The porosities of HAp/cellulose composites decrease, and their compressive strengthincrease as compared to those of cellulose. Thermogravimetric analysis confirms the highest thermal stability of theprepared composites