Placement Distance Research Articles

Study of CO Gas Dilution in Forcing Ventilation System at Ramp Down KKRB 4 Utama, Pongkor, West Java

CO is a hazardous gas formed from the reaction of explosives that lack oxygen balance. These explosives have the potential to generate toxic gases, including CO. It is crucial to minimize CO concentration at the work site by ensuring proper air circulation. This study aims to examine the impact of varying ducting distances on CO gas dilution, using the gas diffusion coefficient value as a basis. The research method employed is observational, involving the assessment of CO gas dilution in the tested tunnel at varying distances from the working front to the sensor. The research was conducted on the Ramp Down KKRB 4 Utama. Result of the research is the most ideal carbon monoxide reduction time at RD KKRB 4 Utama is shown at sensor placement distance 1 using the blow system, where A Sensor takes 2.21 hours and B Sensor takes 1.06 hours to reach a concentration level below the TLV (Threshold Limit Value) 50 ppm.

Numerical simulation of shelter effect assessment for single-row windbreaks on the periphery of oasis farmland

Dust storms, resulting from aeolian erosion, pose significant environmental hazards, while farmland is one of the main sources of dust storm release. An effective strategy to mitigate surface wind speed and curb dust emissions involves the establishment of windbreaks on the periphery of oasis farmland. This study conducts a series of numerical simulations using computational fluid dynamics (CFD) to explore the airflow fields around windbreaks with diverse systematic structural parameters, encompassing porosity, planting spacing, and fence effects. The main findings are as follows: (1) When the vegetation porosity is consistent (e.g., porosity α = 0.7, 0.8, and 0.9), exact geometry results can effectively reflect the distribution of wall shear stress, while the porous medium model overlooks these details. (2) The “Venturi effect” contributes to the acceleration of surface erosion and improper planting spacing results in an elevation of near-surface velocity. Planting spacing of 0.5 m demonstrates superior wind speed reduction performance, mitigating aeolian erosion and accumulation. (3) When the fence is positioned at l = 5h (h represents the height of the windbreaks), the flow field around the windbreaks is minimally influenced. The optimal placement distance for fences should be close to the windbreaks, featuring minimal porosity (l = 0 h, α = 0.1), extending the shelter distance from 3 to 4 h to 5–6 h. The research results can provide a theoretical basis for optimizing the plant configuration of biological desertification control and soil erosion control measures.

The use of an embryo transfer simulator to compare transfer techniques and pregnancy outcomes among physicians

To evaluate the association between embryo transfer techniques and pregnancy outcomes. This is a prospective observational study with a retrospective cohort. University Clinic. Patients underwent embryo transfers between 2015 and2020. Fourteen physicians performed 25 mock embryo transfers on the embryo transfer simulator and completed a questionnaire assessing preferred embryo transfer techniques. Quantitative performance metrics on the embryo transfer simulator were measured. Individual physician embryo transfer success rates were retrospectively collected from all fresh and cryopreserved embryo transfers between January 1, 2015, and January 1, 2020. Associations between embryo transfer techniques (preferred technique and simulator performance metrics) and each physician's historical patient pregnancy outcomes were assessed. Associations between embryo transfer techniques and live births were assessed. There were significant differences in embryo transfer techniques between physicians, including touches to the fundus, distance to the fundus, duration of embryo transfer, duration of the complete procedure, time spent navigating the cervical canal, velocity of embryo expulsion, time waited after embryo expulsion, and total score on the embryo transfer simulator. After controlling for confounders and multiple transfers per physician, the duration of embryo transfer was significantly associated with live birth, with longer durations associated with decreased live birth rates. Shorter placement distance to the fundus and higher velocity of embryo expulsion were both significantly associated with higher rates of ectopic pregnancy. This study revealed significant differences in transfer techniques among physicians. The use of the embryo transfer simulator for physicians in practice can elucidate differences and create opportunities for data-driven improvement in embryo transfer success rates.

Pengaruh Komposisi Partikel Styrofoam dan Resin Epoksi pada Komposit Peredam Suara

<p><em>Styrofoam</em><em> (Extruded Polystyrene) waste can be used as a soundproofing material. This study aims to determine the effect of the particle composition of Styrofoam and epoxy resin on the performance of soundproofing composites. The composition between Styrofoam particles and epoxy resin is 20:20; 20:30; and 20:50 grams. Sound absorption test using PVC impedance tube 100 cm long, 15 cm diameter, and 5 mm thick. The variation in the placement distance of the composite from the sound source is 25; 50; and 75 cm and was measured using the sound level meter application. This type of test sound uses a single tone in the frequency range of 0-600 Hz which is recorded per 5 seconds. Composite performance analysis is reviewed based on media density, composite morphological characteristics of Image-J software, and sound absorption coefficient values. The results showed that the greater the composition had increased the density value of composite particles accompanied by a decrease in pore area in the composite media which resulted in a sound absorption coefficient of 15.61 dB at a composition of 20:50 with a distance of 25 cm from the sound source.</em></p>

Evaluation of the Coolnet Placement Distance to Direct Evaporative Cooling to Increase Potato Seed Production in Aeroponic Systems with Root Zone Cooling in the Lowlands

Evaluation of the placement of the coolnet distance on direct evaporative cooling is needed in order to reduce the wilting percentage and improve seed production of potatoes. The aim of the study was to obtain the appropriate coolnet distance for the growth and development of aeroponic potato seedlings in evaporative cooling and root zone cooling applications in the tropical lowlands. The factors tested were: 1) Evaporative cooling (JEvap) distance: JEvap1 (25 cm from the top zone of the plant), JEvap2 (50 cm from the top zone), and Jevap3 (60 cm), and 2) Varieties (V): V1 (MZ), V2 (Granola K), V3 (Granola L). The design used was completely randomized design with 2 replications. Growth data and results were analyzed by the F test and continued with Duncan's Multiple Range Test (DMRT) at 5% level. The results showed that the direct evaporative cooling method and the coolnet spacing of 50-60 cm which were integrated with root zone cooling created an air temperature at the top of the plant 26-28 °C, reduced the percentage of burnt wilting, and increased the number of tubers by an average of 31.4 to 41.7 tubers/plant. Keywords: Aeroponic, cooling system, growth environment, hidroponic, limited control.

REDUCTION OF TOTAL DRAG FOR FINITE CYLINDERS IN TURBULENT FLOW WITH A HALF-C SHAPE UPSTREAM BODY

The effect of an upstream half-C shape body on the reduction of the total drag of a finite circular cylinder is investigated experimentally. Five main cylinders, each with an upstream half-C shape body placed at five upstream positions, a total of 25 different configurations, are considered during the experimentation at a Reynolds number in the range of 1.2 × 10<sup>4</sup> to 1.6 × 10<sup>5</sup>. The aspect ratios of the main cylinders are 1.25, 2.09, 3.03, 3.78, and 4.90 and the upstream bodies are taken as 90° peripheral cut-outs of the respective main cylinder. The total configuration drag coefficient is calculated from the time-averaged drag force on the configuration and compared with the drag coefficient of the respective main cylinder. Results suggest that at least 20% of the total drag of the configuration might be reduced with the upstream half-C shape body, and the reduction varies with the main cylinders' aspect ratio and the upstream body placement distance. The maximum drag reduction is about 55% if the half-C shape body is placed at an upstream distance of 66% of the main cylinder diameter with an aspect ratio of 3.03 and at a Reynolds number of 1.8 × 10<sup>4</sup>. A critical distance ratio is found beyond which drag cannot be reduced by the upstream half-C shape body, and the attribution might be given to a formation of intermittent swirling flow in the cavity mode.

Design and Testing of a Bearing less Piezo Jet Micro Heat Sink

The present study utilized piezoelectric ceramics (PC) as actuators to design five new piezoelectric heatsinks and preliminarily investigated the different design types and their operating conditions, such as the frequency, placement distance, thickness between piezoelectric sheets, piezoelectric sheet size, and noise produced. The results showed that when the micro heatsink bearingless piezo jet was placed too close to the heat source, the high temperature sucked back the surrounding fluids, causing the fluid chamber temperature to rise and the cooling effect to be reduced. Therefore, the heatsink should be placed between 10 and 20 mm from the heat source. With the proper distance, the heat convection coefficient was 200% greater than that of a traditional rotary fan. The cooling effect of the five heatsinks was calculated using the thermal analysis method, and the results indicated that the convection thermal resistance of the best heatsink could be reduced by about 36%, and the frequency, flow velocity, and noise were all positively correlated. When the supplied piezoelectric frequency was 300 Hz, the noise level was similar to that of a commercial rotary fan. The tested heatsinks had one of two volumes depending on the size of the piezoelectric sheet, including 3150 mm3 or 4050 mm3, respectively. An array of 25 to 32 micro heatsinks of the same size were connected in series. The power consumption of any single heatsink was 10% of that for a rotary fan. Among the five types of heatsinks, the best type had a piezoelectric sheet diameter of 41 mm, a piezoelectric thickness of 2 mm, and an opening length of 4 mm. Furthermore, the best operating conditions were found at a frequency of 300 Hz and a placement distance of 20 mm.

P‐57: Student Poster: Improved Modulation Transfer Function (MTF) for Aerial Image Formed with AIRR by Use of Two Transparent Spheres

In the AIRR optical system that combines transparent spheres, the MTF due to quasi‐parallelization is greatly improve according to the placement distance of the transparent spheres. Due to the effect of aberration, the MTF reaches its maximum when the sphere is placed outside its Paraxial approximate focal length.

Variasi Nilai Tegangan Percik Arrester Akibat Pengaruh Kapasitas Trafo Daya dan Jarak Arrester

The ability of each substation to withstand lightning and overvoltage affects the power distribution of the power system. In order to make the best operation of the substations, it is necessary to install Arresters which are used to protect the transformers in each substation from overvoltage caused by lightning surges. In this study, the effect of capacity on the placement distance of the arrester is discussed with 30 MVA and 60 MVA transformers. The purpose of this study was to determine the effect of the power transformer capacity of the four substations on the value of the arrester spark voltage and to obtain the optimal arrester installation technique at each substation using the Lagrange optimization method. Lagrange optimization method is used to determine the optimal distance between the arrester and the power transformer. The calculation results show that in a transformer with a capacity of 60 MVA, the Arrester spark voltage occurs at t = 20 microseconds with a voltage drop of 390.49 kV. Meanwhile, in a transformer with a capacity of 30 MVA, the Arrester spark time is at t = 13.9 microseconds with a voltage drop of 266.3 kV. This shows the capacity of the transformer that affects the magnitude of the Arrester's spark voltage and the spark time. Thus, the smaller the transformer capacity, the smaller the arrester spark time with the large voltage drop

Design of Corrective Inserts for Patients with Feet Dysfunctions With Reverse Engineering Techniques

These days CAD systems are successfully used in medicine and orthopaedics. Nevertheless, there is still a need of developing of an efficient methodology of their use in case of designing of products which fulfil patient’s requirements according to their disabilities and faulty postures. The cognitive goal of the presented work was disposure to answer the question whether? And how reverse engineering techniques would enable the design of an orthopaedic inserts for people with static flat-valgus foot. The accomplishment of the research problem defined in such a way required working out of solutions for the following detailed research problems: in which way and how to make feet casts to get the precise models – the input data for the 3D scanning process, which 3D scanning technique to apply, taking into consideration available technical means, and how to determine the placement distance of the corrective element for the designed correction insert. The main research areas encompassed inter alia: interviewing the potential patient and examining of their lower limb, making of feet pedographs, creating of feet casts negatives, preparing of casts for 3D scanning, models digitization, and feet inserts design.

Placement Distance of Exit Advance Guide Sign on an Eight-Lane Expressway Considering Lane Changing Behavior in China

The reasonable placement of the advance guide signs (AGSs) is important in improving driving efficiency and safety when exiting an expressway. By analysing the lane-changing process when approaching an exit on new two-way eight-lane expressways, we modified the tradi-tional AGS model lane-change distance formula. To this end, a field experiment was designed to explore the lane-change traversal time at the free flow condition (LOS 1). Considering the limitations of the experimental equip-ment, lane change distance at the worst levels of service was explored using VISSIM simulation. The results show that the eight-lane changing distance based on modified theoretical calculations, revealed a minor difference with VISSIM simulation in free flow condition. Further-more, placement distance at the worst levels of service are discussed. Then placement distance of all-level AGSs is recommended to be 3 km, 2 km, 1.2 km, and 0.8 km, considering the driver's short-term memory attenuation calculation formula. Determining the two-way eight-lane AGS placement distance from the perspective of LOS can provide a basis on which to supplement the existing stan-dards and references for the AGS placement distance af-ter the expressway expansion in China.

ТЕНДЕНЦИИ РАЗВИТИЯ АРХИТЕКТУРНОЙ ТИПОЛОГИИ ЕВРЕЙСКИХ ОБЩИННЫХ ЦЕНТРОВ

TThe article discusses the analysis of trends in the development of the architectural typology of Jewish community centers, substantiates the topicality of its study. The stages of development of architectural typology are described, based on graphic-analytical schemes of planning decisions of historical types of Jewish community centers. Conclusions are drawn about the continuity of the functional planning organization of the religious functional planning component of Jewish community centers. The conclusions of the analysis of experience in the implementation of Jewish centers are presented. It reveals the main factors influencing the formation of space-planning solutions. The nature of the town-planning placement and walking distance of Jewish community centers in St. Petersburg is considered. Based on the analysis of foreign and domestic experience in the design and implementation of such buildings at the present stage, the features of the functional and spatial organization of Jewish community centers are identified, and the principles of a consolidated classification of such buildings are formulated. It is shown that there is a relationship between the dominant functional and planning component of the Jewish community center and the nature of its planning organization. Approaches to the consideration of the construction of the architectural image of the Jewish community center from the point of view of morphology and semiotics are briefly outlined. Promising areas of research are formulated that reveal national identity through the semiotics of the architectural image of the Jewish community center.

FACTORS ASSOCIATED WITH PERCEIVED STIGMA AMONG COMMUNITY MEMBERS LIVING CLOSE TO LEPROSY CENTRE IN MALAYSIA

Introduction: Stigma is strongly associated with leprosy that affects the social status of leprosy patients. The main problem of leprosy is that it presents a negative stigma and a very poor image to the patient. Stigma is a sign that represents unwanted traits that are contrary to one's personality within the community. Stigma is also a social process that results in the patient being unwanted. The purpose of this study was to determine perceived stigma among community members living close to leprosy center in Malaysia. Methods: A cross-sectional study was conducted among the communities around leprosy center from June to October 2019. A total of 260 persons were selected by simple random sampling to answer question on demographic, socioeconomic status, placement distance, information source, infected family, knowledge, attitude and stigma. Data were analyzed using Pearson correlation, independent t-test and multiple linear regression. Results: The mean stigma score obtained was 11.41 (SD=5.38). Negative attitude among community were significantly correlated with higher stigma scores (aOR 0.365, 95% CI 0.20, 0.53). Conclusion: The stigma scores obtained in this study were lower compare to other countries and negative attitudes are a major contributing factor to the stigma toward leprosy patients. This negative attitude can be avoided by raising awareness of leprosy among community living nearby to leprosy center.

PMMA Application in Piezo Actuation Jet for Dissipating Heat of Electronic Devices

The present study utilizes an acrylic (PMMA) plate with circular piezoelectric ceramics (PC) as an actuator to design and investigate five different types of piezo actuation jets (PAJs) with operating conditions. The results show that the heat transfer coefficient of a device of PAJ is 200% greater than that of a traditional rotary fan when PAJ is placed at the proper distance of 10 to 20 mm from the heat source, avoiding the suck back of surrounding fluids. The cooling effect of these five PAJs was calculated by employing the thermal analysis method and the convection thermal resistance of the optimal PAJ can be reduced by about 36%, while the voltage frequency, wind speed, and noise were all positively correlated. When the supplied piezoelectric frequency is 300 Hz, the decibel level of the noise is similar to that of a commercial rotary fan. The piezoelectric sheets had one of two diameters of 31 mm or 41 mm depending on the size of the tested PAJs. The power consumption of a single PAJ was less than 10% of that of a rotary fan. Among the five types of PAJ, the optimal one has the characteristics that the diameter of the piezoelectric sheet is 41 mm, the piezoelectric spacing is 2 mm, and the length of the opening is 4 mm. Furthermore, the optimal operating conditions are a voltage frequency of 300 Hz and a placement distance of 20 mm in the present study.

RANCANG BANGUN SISTEM PEMANEN ENERGI ANGIN EXHAUST FAN DENGAN PENGARUH JARAK TURBIN ANGIN SUMBU HORIZONTAL BILAH EXHAUST FAN

Energy demand in Indonesia is increasing, especially in the realization of electricityconsumption which reached 20.18 TWh in July 2020. In fulfilling energy, Indonesia is stillsupported by fossil energy. Indonesia's fossil energy reserves continue to decline, so it isnecessary to increase the non-fossil energy, one of which is wind energy. Wind exhaust fanoutput is waste energy that has the potential to be developed as a micro-scale wind powerplant. The Design and Construction of the Exhaust Fan Wind Energy Harvesting System withthe Effect of the Horizontal Axis Wind Turbine Distance (HAWT) of the Exhaust Fan Blade hasbeen done, the test of this study determine the optimal output power of the generator byconsidering the exhaust fan performance. The test results show that the closest distance of 10cm produces maximum wind speed and power, but the optimal placement distance for theturbine designed is 20 cm with an output power of 1.50 Watt and an increase in exhaust fanconsumption power of 0.38, with the power that can be harvested is 1.50-0.38 = 1.12 Watt,greater than the other test distances.

Demersal Fish Diversity Index in Cirebon Waters, West Java

This study aims to analyze the distance between the placement of the base fish aggregating devices (FAD) from the beach, the composition of the catch, identify fish species and determine the diversity of fish caught at different distances of the base FAD in Cirebon waters. The research method was carried out descriptively by census. Data analysis method for demersal fish diversity index value (H') using Shannon-Wiener and t-test. Sampling of respondents was carried out by census as many as 20 basic FAD fishermen. The research location is in the Cangkol Tengah Fishermen Association, Cirebon City. The results of this study indicate that the number of fish species caught on FADs with a distance of <12 miles was obtained 10 species with 6,784 fish, the largest number of fish caught was snapper (Lutjanus Campechanus) as many as 2,040 fish with a percentage of 30.2% of the total number of fish. The whole fish caught, while the fish with the largest weight was snapper for distances <12 miles with an average weight of 658.92 kg or 30% of other types of fish. The number of fish species caught on FADs with a distance of >12 miles obtained 10 species with 9.217 fish, the highest number of fish caught was snapper (Lutjanus Campechanus) as many as 2,884 fish with a percentage of 27.97% of the total number of fish caught, while the fish with the greatest weight is snapper with an average weight for distances >12 miles of 988.39 kg or 30% of other types of fish. The magnitude of the demersal fish diversity index value at the base FAD placement distance <12 miles was 1.6672 and more than 12 miles was 1.8137 which means that there is no significant difference and the diversity index category is small because the value of H '≤ 2.

Assessment of Photovoltaic Capabilities in Urban Environments: A Case Study of Islamabad, Pakistan

Abstract Photovoltaic (PV) estimation in an urban environment requires detection of rooftop area, design of PV system based on optimization on PV placement distance and the study of additional benefit of lower cooling load of building by shading provided by PV panels. The study is aimed at policymakers to introduce renewable energy policy toward net-zero energy buildings in urban areas. In this research, the capital city of Pakistan, Islamabad, is analyzed for rooftop PV capabilities using deep learning algorithms. The area of the rooftop is calculated by extracting buildings in high-resolution satellite imagery using a deep learning algorithm. The site location is analyzed for available solar energy resources. The distance between the rooftop-PV array is optimized based on self-shading losses, coefficient of performance, energy yield, net-zero energy analysis, and reduction of cooling load of the building provided by PV arrays as shading devices. The 40-km2 area of Islamabad considered in this research can generate 1038 GWh of solar energy annually from its 4.3-km2 rooftop area by installed capacity of 447 MW PV panels rows placed at 0.75 m apart. The electricity generated by Islamabad can curtail residential load from the national grid and form a near net-zero energy zone while the electrical energy from the grid can be provided to the industries to enhance the economy and reduce unemployment in Pakistan.

Програми раннього вступу до університетів та коледжів для обдарованих старшокласників у США

У статті досліджено програми раннього вступу до університетів та коледжів для обдарованих старшокласників у США. Схарактеризовано спеціальні програми для обдаро-ваних старшокласників, які в своєму інтелектуальному, емоційному та особистісному розвитку на декілька років випереджають ровесників. Доведено, що всі програми раннього вступу до університетів у різних штатах базуються на стратегіях прискореного і збагаченого навчання; виокремлено організаційні відмінності такого навчання у різних штатах. Проаналізовано сутність таких програм раннього вступу, як Міжнародний Бакалаврат, академічні олімпіади й конкурси, літні школи, волонтерські програми, тощо. Авторами окреслено шляхи імплементації американського досвіду раннього вступу до закладів вищої освіти в Україні.

Simulation Based Topology Optimization in Wireless Sensor Network

Background: Wireless Sensor Network (WSN) is among the most promising technologies that can be used to monitor crucial ambient conditions. WSNs are capable of effectively monitoring the environmental parameters and any habitat necessary to be investigated. Sometimes, it is very important to periodically monitor the critical environmental parameters such as humidity, temperature, soil moisture, fire, volcanic eruptions, Tsunamis, seismic waves and many more to react proactively to save lives and assets. This research work is an endeavor to present the importance and to determine the precise inter- nodal distance required for distinct applications. The networks of the different terrain area and internodal distance are deployed to evaluate and analyze the performance metrics such as a number of messages received average end to end delay (secs), throughput (bps) and jitter (secs). The influence of varying inter-nodal distance on the performance of WSN is determined to select the most appropriate value of the distance between nodes in particular monitoring application. The patents related to the topology based analysis of wireless nodes are reconsidered. Methods: The placement of nodes and inter-nodal distance significantly influences the operation and performance of WSNs by diverging the ability of sensors to observe an event of interest and transmission of information to data aggregation nodes (sink nodes). Moreover, effective sensor placement also affects the resource management. The investigation of specific regions and habitats has peculiar constraints of node placement and inter-nodal distance making it highly application specific. In this research work, the intent is to monitor an entire area to attain optimum coverage to detect the occurrence of a significant event. The node placement and inter-nodal distance can be classified on the basis of the role played by the deployed nodes, like, placement of ordinary sensor nodes/Reduced Function Devices (RFDs) and relay nodes/Full Function Devices (FFDs), respectively. The sensors are compatible with IEEE 802.15.4/ZigBee protocol and application implemented is Constant Bit Rate (CBR) generator. This paper analyzed and evaluated the influence of placement and inter-nodal distance of RFDs to the data aggregation ability of sink node. The terrain area (m2) of different sensor networks deployed are 110×110, 200×200, 300×300, 400×400 and 500×500, respectively. The number of sensor nodes is constant equal to 100 to evaluate their ability to provide optimum performance. The parameter internodal distance is varied, keeping all other parameters constant to effectively evaluate its influence. The simulations are carried out on QualNet 6.1 simulator. Results: The variation in inter-nodal distance significantly influences the performance metrics of the network such as the number of messages received, average end to end delay, throughput and jitter. In this paper, the distance between sensor nodes and terrain areas of grid topology is varied accordingly to deduce that which value of the inter-nodal distance and network provides optimum performance. The thorough evaluation of the simulation results presented that the inter-nodal distance of 30 m and terrain area of 300×300 m2 has generated optimum performance by providing the highest number of messages received (208) and highest throughput (2544.34 bps). It is also capable of providing minimum end to end delay (14.45 secs) and lowest jitter (6.67 secs). Conclusion: The objective of this paper to determine the optimum inter-nodal distance and terrain area of a WSN of 100 nodes is successfully achieved. It is analyzed and evaluated that the inter-nodal distance of 30 m and terrain area of 300×300 m2 enhance and optimize the network performance significantly.

The impact of cathode surface roughness and multiple breakdown events on microscale gas breakdown at atmospheric pressure

Gas breakdown is typically driven by Townsend avalanche and predicted mathematically by Paschen’s law (PL). Gas breakdown deviates from PL at microscale due to field emission, which depends critically on electrode condition; however, understanding of the impact of initial electrode surface roughness and multiple breakdown events on breakdown voltage is incomplete. This paper assesses the variation of breakdown voltage for a pin-to-plate electrode setup in air at atmospheric pressure for gap distances of 1 ± 0.5 μm, 5 ± 0.5 μm, and 10 ± 0.5 μm with different surface roughnesses. Breakdown voltage generally increases with increasing gap distance and decreasing surface roughness for a single breakdown event; however, the breakdown voltage after ten breakdown events does not depend on initial gap distance. Atomic force microscopy and optical microscopy show that multiple discharges create circular craters on the flat cathode up to 40 μm deep, with more pronounced craters created at smaller gap sizes and greater cathode surface roughness. The resulting effective gap distances (deff, the sum of cathode placement distance and crater depth) for subsequent breakdown events are similar to those of the initially larger gap distances. Moreover, deff becomes sufficiently large to exceed the Meek criterion for streamer formation, indicating a potential for breakdown mechanisms to change from field emission to Townsend avalanche to streamer formation for a single electrode separation distance. The resulting impact of this change in the breakdown mechanism could have significant implications for ensuring consistent microdevice operation.