Open Micro Research Articles

Comparative thermo-hydraulic analysis of periodic stepped open micro pin-fin heat sink

Comparative thermo-hydraulic analysis of periodic stepped open micro pin-fin heat sink

Construction of silver-coated high translucent zirconia implanting abutment material and its property of antibacterial

High translucent zirconia (HTZ) has excellent mechanical properties, biocompatibility, and good semi-translucency making it an ideal material for aesthetic anterior dental implant abutments without antibacterial properties. In the oral environment, the surface of the abutment material is susceptible to microbial adhesion and biofilm formation, which can lead to infection or peri-implantitis and even implant failure. This study aims to promote the formation of a biological seal at the implant-soft tissue interface by modifying the HTZ surface, using the load-bearing capacity of the aluminosilicate porous structure and the broad-spectrum antibacterial effect of silver nanoparticles to prevent peri-implant bacterial infection and inflammation and to improve the success rate and prolong the use of the implant. FE-SEM (field emission scanning electron microscopes), EDS (energy dispersive spectroscopy), and XPS (X-ray photoelectron spectroscopy) results showed that aluminosilicate non-vacuum sintering can form open micro- and nanoporous structures on HTZ surfaces, and that porous aluminosilicate coatings obtain a larger number, smaller size, and more uniformly shaped silver nanoparticles than smooth aluminosilicate coatings, and could be deposited deeper in the coating. The ICP-AES (inductively coupled plasma-atomic emission spectroscopy) results showed that the early silver ion release of both the smooth silver coating and the porous silver coating was obvious, the silver ion concentration released by the former was higher than that of the latter. However, the silver ion concentration released by the porous silver coating was higher than that of the smooth coating when the release slowed down. Both smooth and porous silver coatings both inhibited E. coli (Escherichia coli), S. aureus (Staphylococcus aureus), and L. acidophilus (L. acidophilus), and porous silver coatings had stronger antibacterial properties. The silver coating was successfully constructed on the surface of HTZ, through aluminium silicate sintering and silver nitrate solution impregnation. It was found that the high concentration environment of silver nitrate solution was more advantageous for nano-Ag deposition, and the non-vacuum sintered porous surface was able to obtain a larger number of nano-Ag particles with smaller sizes. The porous Ag coating exhibited superior antibacterial properties. It was suggested that the HTZ with silver coating had clinical application, and good antibacterial properties that can improve the survival rate and service life of implants.

Thermo-hydraulic investigation of open micro prism pin fin heat sink having varying prism sides

The current trend of miniaturization in many electronic devices, like computer processors, high-speed servers, MEMS devices, etc., has shown augmented performance. Still, thermal management is a significant concern for them. The present work performed a numerical analysis on the microchannel heat sink's open micro prism pin fin configuration (MCHS). The influence of prism pin fin sides (3 to 9) has been studied for copper substrate and working fluid water (single phase fluid flow). Finite volume-based commercial code has been opted to perform the numerical simulations. The present configurations simulated different Reynolds numbers (50–300) under the heat flux of 500 kW/m2. Observation revealed that the four-side arrangements have the best performance due to prominent secondary flow leading to efficient fluid mixing, whereas three-side configurations have the worst performance. Further, an increase in pin fin sides from 5 to 9 has almost negligible variation in thermal and hydraulic characteristics because of similar fluid flow characteristics. The four-side micro prism pin fin configuration has been further analysed by varying the prism radius from 0.175 mm to 0.325 mm. It was observed that a prism radius between 0.250 mm and 0.275 mm led to optimum overall performance due to more stable secondary fluid flow.

Micro Business Based Business Development in Tourist Village Case Study: Lembur Sawah Tourist Village, Bogor, Indonesia

Indonesia is a maritime and archipelagic nation-based country. No wonder Indonesia has many of the best tourist attractions. Indonesian tourism is one of the country's largest sources of foreign exchange, so the presence of Covid 19 has had a huge impact on Indonesia and several tourist areas in Indonesia such as Bali. However, the Indonesian government prepared a new strategy with a focus on developing tourist villages with the aim of popularizing ecotourism and improving the economy of the residents and succeeded in getting people in tourist villages to open micro businesses to simply prepare souvenirs for tourists. In the title above, we will find out some data on micro-enterprises in the village of Lembur Sawah and the impact of the tourism village on the village. This reaserch use qualitative, descriptive-analytical research; the data obtained is in the form of observation results, interview results, and field notes that have been collected. Lembur Sawah has formed a Tourism Mobilization Community that gathers people with the awareness and willingness to process and develop Mulyaharja into a tourist village; the tourism driving group is called "KOMPEPAR MULYAHARJA" and use a promotion mix, promotional objectives, promotional budgets, target visitors, promotional media used, sources of messages and feedback. Lembur Sawah is still very developed to increase visits so that increased visits will help community-owned micro-enterprises, even though they are still trying to organize training, attend exhibitions, and organize events to attract visitors to visit to Lembur Sawah.

THE INFLUENCE OF GIVING COMPENSATION ON EMPLOYEE PERFORMANCE PRODUCTIVITY AT ARIFA MART

Over time, micro, small and medium enterprises or cooperatives will develop rapidly in the future as they are today, many people are willing to open micro, small and medium enterprises. From several places we visited, we got one of the micros, small and medium enterprises, precisely in Blang Pulo, called ARIFA MART. The ARIFA MART business itself has been established since 2017 which is located in Blang Pulo. The name ARIFA MART is also taken from the names of people, namely Arif, Anis, Fatlan. The number of Arifa Mart employees is 25 people, starting from cashiers, goods carriers, and outside guards. With 25 employees, Arifa Mart does 2 work shifts morning – afternoon and afternoon – evening. Arifa Mart has been running its business for about 6 years now, with never a few visitors, Arifa Mart is also well known among the public or students. The method used in this research is quantitative. The results of this study, it can be concluded that more compensation will be given if the employee can work with high loyalty.

Numerical investigations on the effect of multi-dimensional stepness in open micro pin fin heat sink using single phase liquid fluid flow

In present work, the square shaped micro pin fin configuration of microchannel heat sink has been numerically investigated under different geometrical variation. Considering effectiveness of open microchannel, the pin fin height has been varied in two different styles. Firstly, the consecutive pin fins are varied in step of two and three rows. Secondly, the step variations were opted along only the channel length (unidirectional) and along both channel length and channel width (bidirectional). Furthermore, all configurations are having equal convective area so that influence of out of plane mixing can be studied more precisely. Estimated findings clearly indicated that stepped configuration has superior thermo-hydraulic performance compared to uniform configuration due to out of plane fluid motion resulting in enhanced flow mixing. Afterwards, bidirectional step has shown augmented performance compared to unidirectional step heat sink configuration because of enhanced secondary fluid flow and distinct vortices formation behind each pin fins. Among all considered configurations, three stepped bidirectional micro pin fin heat sink has yielded best performance i.e. 28.3% higher heat transfer rate and 2% lesser average bottom wall temperature compared to uniform height pin fin configuration.

Long-term Clinical Outcomes Following Endoscopic Foraminoplasty for Patients With Single-Level Foraminal Stenosis of the Lumbar Spine.

The aim of this study is to evaluate the safety and long-term clinical outcomes of transforaminal endoscopic foraminoplasty using local anesthesia and total intravenous analgesia (TIVA) in patients with single-level lumbar foraminal stenosis and unilateral leg pain. Postoperative pain relief was self-evaluated by 46 consecutive patients using a visual analog scale (VAS) and Oswestry Disability Index (ODI). Patient scores were obtained before the procedure and at 6, 12, 24, and 60 months after surgery. Pain reduction of at least 50% in the VAS score and a decrease of at least 50% or more in ODI score was achieved in 37 of 46 patients throughout the follow-up period. Median VAS score decreased from 7.5 preoperatively to 2.5 postoperatively. Median ODI score decreased from 62% preoperatively to 15% postoperatively. All patients reached 24-month follow-up and 37 patients reached 60-month follow-up. There were no surgery-related complications. Transforaminal endoscopic foraminoplasty performed under local anesthesia and TIVA produces sustained reduction in pain and improves functionality in patients with single-level lumbar foraminal stenosis without complications even in patients with comorbidities. Endoscopic foraminoplasty may be a useful adjunct to open micro decompressive surgery for patients with foraminal stenosis of the lumbar spine LEVEL OF EVIDENCE: 4.

Short Term Clinical Outcome of Micro Lumbar Discectomy in Tertiary Care Center

Background: Minimal invasive open lumbar microdiscectomy has been associated with good success rate and low morbidity. The present study is aimed to evaluate the clinical outcome of patients who underwent open minimal invasive open lumbar microdiscectomy for herniated intervertebral disc.
 Materials and Methods: This is a prospective observational hospital based study of prolapsed lumbar intervertebral disc operated in the department of neurosurgery at Nobel Medical College Teaching Hospital, Biratnagar, Nepal from January 2018 to June 2021. All patients of lumbar herniated intervertebral disc subjected for surgery were included. Recurrent prolapsed intervertebral disc, Disc surgery requiring stabilization was excluded from the study. During surgery types of prolapsed intervertebral disc, level and operative time were noted. In the post-operative period Visual Analogue Scale was used to assess the change in severity of pain. Duration of hospital stay and the complications occurred were also noted.
 Results: The mean age of the study population was was 41.50 (±14.56) years ranging from 20 years to 79 years. The commonest lumbar prolapsed intervertebral disc was at L4-L5 level. The mean operative time was 42 minutes excluding the time for anaesthesia preparation. There was statistically significant difference (p<0.001) in pre-operative and post-operative Visual Analogue Scale. Mean duration of hospital stay was 5.58 (1.87) days.
 Conclusion: A through workup and surgical planning is associated with better outcome avoiding complications in minimal invasive open micro lumbar discectomy.

Sustainable and recyclable synthesis of porous carbon sheets from rice husks for energy storage: A strategy of comprehensive utilization

Converting rice husks into valuable chemicals or advanced materials has attracted significant interests of economic and environmental benefits. In this study, we prepared rice husk-derived porous carbon sheets (PCS) by sustainable and recyclable salt activation. The employed NaCl/KCl salt mixture was not only the template agent for mesopores, but also necessary for the formation of 2D carbon structure. The evolution of porosity and carbon morphology after activation was systematically investigated. The optimal product 4PCS-800-2 owned a high surface area and numerous open micro-/mesopores arraying on planar carbon sheet. Benefiting from these features, 4PCS-800-2 exhibited high specific capacitance (288 F g−1 at 0.5 A g-1), efficient pore utilization, excellent rate capability and cyclic stability as electrode material. It was noting that rice husks were also continuously converted into xylose and lignin/silica nano-spheres in prior to the synthesis of PCSs. Hence a comprehensive utilization of rice husk was realized and the whole components had been converted into valuable products.

Behandeling van lumbale discushernia: open versus endoscopische discectomie?

Open (micro) discectomie is a routine treatment for patients with a lumbar disc hernia and incapacitating sciatica, resistant to conservative treatment. Alternatively, the full-endoscopic discectomy has been increasingly performed over the past years. While the surgical instrumentation for this approach has improved and the necessary specialized training is widely available, the technique remains challenging for the surgeon and the assumed/theoretical advantage regarding patient morbidity is still unproven. When compared to open (micro) discectomie, the existing literature fails to attribute significant decreases in length of hospital stay or complication rates to the full-endoscopic approach, therefore making the cost-benefit analysis uninteresting due to the higher associated cost. The structural lack of financing of Belgian hospitals leads to intrinsic budgetary limitations which are emphasized if the hospitals have to carry the extra costs related to endoscopic disc surgery themselves.

Amine-functionalized Cu-MOF nanospheres towards label-free hepatitis B surface antigen electrochemical immunosensors.

Metal-organic framework (MOF) nanomaterials offer a wide range of promising applications due to their unique properties, including open micro- and mesopores and richness of functionalization. Herein, a facile synthesis via a solvothermal method was successfully employed to prepare amine-functionalized Cu-MOF nanospheres. Moreover, the growth and the morphology of the nanospheres were optimized by the addition of PVP and TEA. By functionalization with an amine group, the immobilization of a bioreceptor towards the detection of hepatitis B infection biomarker, i.e., hepatitis B surface antigen (HBsAg), could be realized. The immobilization of the bioreceptor/antibody to Cu-MOF nanospheres was achieved through a covalent interaction between the carboxyl group of the antibodies and the amino-functional ligand in Cu-MOF via EDC/NHS coupling. The amine-functionalized Cu-MOF nanospheres act not only as a nanocarrier for antibody immobilization, but also as an electroactive material to generate the electrochemical signal. The electrochemical sensing performance was characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The results showed that the current response proportionally decreased with the increase of HBsAg concentration. More importantly, the sensing performance of the amine-functionalized Cu-MOF nanospheres towards HBsAg detection was found to be consistent in real human serum media. This strategy successfully resulted in wide linear range detection of HBsAg from 1 ng mL-1 to 500 ng mL-1 with a limit of detection (LOD) of 730 pg mL-1. Thus, our approach provides a facile and low-cost synthesis process of an electrochemical immunosensor and paves the way to potentially utilize MOF-based nanomaterials for clinical use.

An open, modular, and flexible micro X-ray computed tomography system for research.

In this paper, a modular and open micro X-ray Computed Tomography (μXRCT) system is presented, which was set up during the last years at the Institute of Applied Mechanics (CE) of the University of Stuttgart and earlier at the Institute of Computational Engineering of Ruhr-University Bochum. The system is characterized by its intrinsic flexibility resulting from the modular and open design on each level and the opportunity to implement advanced experimental in situ setups. On the one hand, the presented work is intended to support researchers interested in setting up an experimental XRCT system for the microstructural characterization of materials. On the other hand, it aims to support scientists confronted with the decision to set up a system on their own or to buy a commercial scanner. In addition to the presentation of the various hardware components and the applied modular software concept, the technical opportunities of the open and modular hard- and software design are demonstrated by implementing a simple and reliable method for the compensation of bad detector pixels to enhance the raw data quality of the projections. A detailed investigation of the performance of the presented system with regard to the achievable spatial resolution is presented. XRCT datasets of three different applications are finally shown and discussed, demonstrating the wide scope of options of the presented system.

Laser Welding Influence on Corrosion Rate of Galvanized Sheets of DP600 Automobilistic Alloy

Corrosion rate behavior of laser welded dual-phase galvanized steel, DP 600, has been assessed in comparison with the material without the laser weld, in 3.5% NaCl solution. Three combinations of both scanning speed and laser power parameters were selected, maintaining the thermal input of 30 J mm-1, calculated as the ratio between the laser beam power [W] and the scanning speed [mm s-1]. The corrosion studies included measurements of open circuit potential, micro and macro polarization, showing higher corrosion rates as scanning speed decreased. Optical microscopy showed the formation of a grain size refined morphology in the heat affected zone and fusion zone. A mechanism has been proposed to explain the corrosion behavior as a function of the laser parameters, which dictated the galvanized coating vaporization.

Intelligent Micro Energy Grid in 5G Era: Platforms, Business Cases, Testbeds, and Next Generation Applications

As fifth-generation mobile communication systems give rise to new smart grid technologies, such as distributed energy resources, advanced communication systems, the Internet of Things, and big data analytics, the development of novel platforms and business models that ensure reliability and profitability of microgrid operations become increasingly important. In this study, we introduce an open micro energy grid platform to operate the widely distributed microgrids in Korea. Subsequently, we present commercial microgrid business models supported by the open micro energy grid platform equipped with an artificial intelligence engine and provide test results from testbeds connected to the platform. In contrast to the existing microgrid business models in the market, we propose a universal architecture and business model of the future microgrid, comprising (i) an energy robot-management operation business model, (ii) electric vehicle-based demand response, (iii) blockchain technology for energy trading, and (iv) a service-oriented business model. Finally, we propose a new business model for an intelligent virtual power plant (VPP) operator along with the architecture of the VPP and its proof of concept (PoC). We expect the proposed business model to provide energy solution providers with guidelines to develop various VPP services.

A complex approach to assessing porous structure of structured ceramics obtained by SPS technique

Spark plasma sintering (SPS) is a highly prospective technology providing rapid consolidation of nano-disperse compositions into structured ceramics with complex structural organization. Characterizing pore structure of such systems remains a challenge due to different types, size and shape of the pores as well as structural defects occurring in the material, thus requiring special methods to quantify certain porosity type. The paper presents a complex approach to studying structure of SPS hematite-based structured ceramics. The method involves a number of gas, intrusion and electron microscopy probing techniques to characterize open and closed pores in the ceramics bulk. Low temperature nitrogen sorption has been implemented to estimate open micro- and mesoporosity in the size range 0.7–50 nm using BET, BJH and t-plot methods to process experimental data. Additionally, structural peculiarities of consolidated structured ceramics have been studied using temperature-programmed reduction (TPR) with the kinetic analysis of the results being carried out. Volume of macropores sized above 50 nm has been measured with mercury intrusion. Closed pores and structural defects have been quantified with SEM and FIB/SEM tomography. By comparing experimental and estimated results we have shown that addressing all porosity types provides a highly precise structural characterization of the material.

A Study on the Importance of Entrepreneurship Training for the Formation of Entrepreneurs

This article aims to identify and analyze the value of entrepreneurship training as a tool for training entrepreneurs to open micro and small enterprises, training and for good business performance, including among young people. Historically, the training of the entrepreneur is taken as an instrument of teaching and learning, but its effectiveness is not proven due to the lack of monitoring in the labor market of those who undergo this type of learning. In view of this, the present study took as a study object the monitoring carried out in 2011 and 2012 of the participants of the Technological Enterprise - EMPRETEC - 2010, promoted by the Brazilian Service of Support to Micro and Small Businesses - SEBRAE, in the city of Macapa, of Amapa, whose data are contained in the publication Impact of EMPRETEC Training on Macapaenses and are presented in a systematic way in this article. The study deals with themes such as entrepreneurship and human development, from which the scientific discussions were extracted to contextualize the problem studied, as a theoretical basis of training effectiveness. Aiming at the formation of the entrepreneurial personality, the authors' studies were used as references: David McClelland, Dornelas, Cannon-Bowers and Salas. The methodology used is to compare the performance of training participants, before and after the training. The result showed that the number of public companies and their formalization more than doubled in relation to the number of companies before the training.

Combination of technology and chemical peels in facial rejuvenation

Skin resurfacing can be done with different procedures like fractional laser, Co2, RF pixel or sublative or different chemical peels. The final goal is to have better skin textures with minimal down time. The idea of this technique is to open micro wholes on epidermal structure (entrance) with technology - LASER OR RF, and allow chemical peel to penetrate in deeper skin layers, with minimal superficial damage, the micro wholes allow that we can apply some anti-age components like vitamin C, retinol, collagen, HA, and other products which may rejuvenate a skin. With this technique skin redness is minimal, and shorter, and down time comparing with aggressive laser or CO2 IS SHORTER.

Capacity-building in open education: an Australian approach

Addressing the gap between global open educational resource (OER) proliferation and the slow adoption of OER and open educational practices (OEP) in Australian higher education, this paper focuses on a capacity-building project targeting academics, academic support staff and educational developers. The conception, design, development, piloting and evaluation of an open, online professional development micro course are detailed, highlighting key aspects of the open design and considerations for sharing and reuse across higher education institutions. The open micro course introduces five key OEP concepts through five contemporary curriculum design topics, using knowledge co-creation activities which engage learners in iterative shaping of the course, and generate artefacts for demonstration and recognition of learning. Opportunities for short to longer term capacity-building which leverage the micro course are also discussed, in response to significant shifts underway in higher education funding and professional development priorities.

Adaptive Intelligent Behavior and Causal Entropy Maximization as a Basis for Microeconomic Information Recovery

In this paper we emphasize the connection between adaptive intelligent behavior, causal entropy maximization and self-organized equilibrium seeking behavior in an open dynamic micro economic systems. This entropy based causal adaptive behavior framework permits the use of information theoretic methods, as a solution basis for the resulting pure and stochastic ill posed inverse economic- econometric problems. We cast the information recovery problem in the form of a binary network and suggest information theoretic methods to recover estimates of the unknown binary behavioral parameters without explicitly sampling the configuration space.

Diagenetic Influence on Fracture Conductivity in Tight Shale and CO2 Sequestration

Most sedimentary rock formations (tight or highly porous) have geochemical characteristics that can lead to significant reactive ion exchange processes in aqueous media in the presence of carbondioxide. While geomechanical properties such as rock stiffness, poisson's ratio and fracture geometry largely govern fluid flow characteristics in deep fractured formations, the effect of mineralization can lead to flow impedance in the presence of favorable geochemical and thermodynamic conditions. Shale caprock which seals more than two-thirds of oil and gas reservoirs have natural fractures that are unevenly distributed in the geosystem. Experimental works which employed the use of analytical techniques such ICP-OES, XRD, SEM/EDS and BET techniques in investigating diagenetic and micro-structural property of crushed shale caprock/CO2-brine system concluded that net precipitation reaction processes can affect the distribution of petrophysical nanopores in the seal rock. XRD analyses indicated the presence of quartz, feldspar and bulk clays (muscovite, chlorite, kaolinite with the quantitative mineralogy estimates varing significantly with respect to quartz-bulk clay ratio in the six samples that were analyzed. Quartz and feldspar are reactive at low pH with the tendency to impact seal integrity. The presence of quartz in shale gives a reasonably high mechanical strength whereas clays make shale easily deformable with a potential to creep. The results showed that geochemical precipitates can be formed such that fluid flow through open micro and macro fractures may be constrained. Peclet-Damköhler reactive flow dimensionless number confirmed diffusion as the governing transport mechanism in aqueous CO2-caprock interaction. Simulation results reported by various researchers suggested that influx-induced mineral dissolution/precipitation reactions within shale caprocks can continuously close micro-fracture networks, while pressure and effective-stress transformation first rapidly expand then progressively constrict them. The presence of traces of carbonate streaks which are soluble in low acidic pH environment is undesirable in caprocks. This experimental research investigated the impact of in-situ geochemical precipitation on conductivity of open micro-fractures under geomechanical stress conditions. Fracture conductivity in core samples of shale caprock with known mineralogical composition from different formations where CO2 injection is on-going are quantitatively evaluated under axial and radial stress using pulse-decay liquid permeametry/core flooding systems. This system incorporates