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Many residential houses in Japan have hip roofs with pitches ranging from 20° to 30°. Recently, roof-mounted photovoltaic (PV) panels have become popular all over the world for environmental conservation. The design of PV systems in Japan is usually based on the Japanese Industrial Standard (JIS) C 8955 (2017). However, the standard does not provide wind force coefficients for PV panels installed near roof edges (up to 0.3 m from the edge) because flow separation at the roof edges causes large up-lift forces on such panels. In this paper, we investigated the wind force coefficients for designing PV panels installed on hip roofs of rectangular and L-shaped low-rise buildings. The roof pitch was set to 25° as a typical value. Rectangular panels were installed almost over the whole roof, including the edge zones. Because the thickness of PV panels and the distance between PV panels and the roof are both as small as several centimeters, it is difficult to make wind tunnel models of PV systems with the same geometric scale as that for buildings. We focused on a numerical simulation using the unsteady Bernoulli equation to estimate the pressures in the space between PV panels and the roof. In the simulation, we used the time histories of wind pressure coefficients on the bare roof, which were measured in a turbulent boundary layer. We propose installing PV panels with small gaps between them along their short sides. The gaps may reduce the wind loads not only on the PV panels but also on the roofing due to pressure equalization. We discuss the optimum gap width from the viewpoint of wind load reduction.

Roll compaction/ dry granulation is gaining importance. Numerous papers have been published and many attempts to model the process are available in the meantime. Johanson published a model in 1965, which is the basis for many further modifications until today. The aim of the paper is to improve process understanding in roll compaction, which can be used to setup a roll compaction process, to design a scale-up strategy or to help in process transfer between different types of roll compactors. Based on some assumptions, simple considerations help to estimate a required densification factor and to visualize the relations between roll diameter, gap width and nip angle. Two recently published papers based on simplified Johansen models are used to visualize the relations between specific compaction force and the maximal pressure experienced by the material. The influence of roll diameter, gap width and compressibility constant are discussed. This helps to estimate, if a scale-up or process transfer is reasonable. The recently introduced dimensionless Midoux-number can also be used to design scale-up or process transfer of roll compaction without knowledge about the maximal pressure. Exploring the simple concepts can help to improve process understanding even without a background in engineering.

Narrow rectangular channels are employed in nuclear research reactors that use plate-type nuclear fuels, high heat-flux compact heat exchangers, and high-performance micro-electronics cooling systems. Two-phase flow in narrow rectangular channels is important, and it needs to be better understood because it is considerably different than that in round tubes. In this study, mechanistic models were developed for the flow regime transition criteria for various flow regimes in co-current air-water two-phase flow for vertical downward flow inside a narrow rectangular channel. The newly developed criteria were compared to a flow regime map of downward air-water two-phase flow inside a narrow rectangular channel with a 2.35-mm gap width under ambient temperature and pressure conditions. Overall, the proposed model showed good agreement with the experimental data.

The change of the gap width is one of the important factors that affect the quality of K-TIG welding, and it is difficult to keep the gap consistent in the welding of large workpieces. Vision technology is a reliable method of weld pool monitoring. To avoid the influence of the strong arc of K-TIG welding, this paper designed a real-time HDR system and based on which, a weld pool and keyhole geometric feature extraction algorithm was proposed. The designed HDR system includes an automatic exposure algorithm which is suitable for HDR and an improved HDR fusion algorithm which uses exposure instead of exposure time for HDR fusion. Finally, the dynamic behavior of the weld pool and weld forming with gradually changing gap were analyzed. And conclude that under the same gap, whether the gap changed from small to large or from large to small suddenly, the weld pool will collapse. In the case of the same gap change rate, the weld forming of the welding direction from a large gap to a small gap is much worse than that from a small gap to a large gap. Therefore, it is necessary to avoid a welding direction from a large gap to a narrow gap.

This study adopts an empirical research method to investigate a number of design parameters for achieving a balance of daylight availability and visual comfort in office buildings using a double skin facade (DSF). This includes its perforation ratio, depth and the gap width from the outer wall. The study refers to the guidelines and performance metrics of the latest Leadership in Energy and Environmental Design system; spatial daylight autonomy (sDA300/50%) and Annual Sunlight Exposure (ASE1000,250) to investigate the daylighting performance of an existing case study building in Egypt. Accordingly, 36 combinatorial simulations have been developed and statistical correlations have been carried out to scrutinize the interrelations between the defined parameters and their effect on the sDA and ASE values. The result indicated that acting on the perforation percentage and skin depths of a DSF provides the greatest influence on buildings’ daylight performance.

Excavation in rock induces the unloading of stress in excavation-disturbed zones and can cause the structural plane to reach shear failure due to the unloading of normal stress. Unloading normal stress tests of a regular sawtooth structural plane were conducted in this study to investigate the influence of the unloading velocities (v) and asperity angles (θ) on mechanical properties and the stability of the structural plane. The average value of normal displacement (Du1) and the shear displacement of unloading (Dsu) gradually increases with an increase in θ and Du1 accounts for 59.70%, 31.81%, and 18.60% of the height of a single asperity under different θ. However, Du2, Ds, and the unloading capacity (Δσn) gradually decreased. Moreover, Ds account for 24.52%, 11.61%, and 7.4% of the length of a single asperity, respectively. With an increase in θ and v, three-dimensional (3D) morphology parameters and normal deformation energy (Un) decreased gradually, indicating that the damage degree of the structural plane increases. The analysis of the evolution of the gap width of the structural plane at the initial point, unloading point, and instability point indicates that the greater the θ or the smaller the v, the lower would be the likelihood for the structural plane to be damaged. Concurrently, its instability is more sudden and the impact tendency is stronger.

A two-dimensional (2D) modeling method, which takes helical structure of superconducting layers in HTS cables into consideration, is proposed to analyze electromagnetic properties of HTS power transmission cable. The model is characterized by E-J power law and H-formulation, and is successfully implemented by finite element software. We first expound the principle of using 2D model to simulate 3D structure of a HTS cable. Then, the modeling process is given. In order to verify the validity of the method, a 3D model was established as the control group, and the current distribution and AC loss were compared. The influence of the 3D structure parameters of the cable has been investigated, including the pitch of superconducting layers and the gap width between HTS tapes.

To reveal the influence mechanism of solidification pressure on the gap width, investigations are performed on the effect of solidification pressure on the interfacial heat transfer mechanism and macroscopically averaged heat transfer coefficient between the H13 ingot and mold. With increasing solidification pressure from 0.1 to 2 MPa, there is an obvious enhancement in the heat transfer from the H13 ingot to the mold. The following quantitative relation between the macroscopically averaged heat transfer coefficient and pressure is proposed: $$ h_{i,P}^{f} = \left( {17.38P^{2} + 155.25P + 1121.7} \right)t^{ - 0.23} . $$ There are three interfacial heat transfer mechanisms, radiation and conduction through the gap between gas pockets and the slightest gap between asperities (or contacting asperities). Increasing pressure can accelerate the formation of the gap between gas pockets, and does not change the maximum value of gap width. In addition, changes in radiation and conduction through the gap between gas pockets are not the main reason for enhancing heat transfer from the ingot to the mold. In the whole process of solidification, increasing pressure is beneficial to retain the intermittent contact at asperities and reduce the macroscopically averaged width of the gap. Consequently, conduction through the slightest gap (or contacting asperities) enhanced by pressure is the major contributor to accelerating heat transfer from the ingot to the mold.

Aim: To evaluate the effect of hydro abrasion versus the conventional drill method of cavity preparation on the clinical performance of composite restoration over one year follow up period. Materials and methods: Twenty patients with occlusal carious lesions were selected and examined with DIAGNO cam and ICDAS visual criteria to select teeth having ICDAS Code 3 or 4. Forty lesions were randomly divided into two groups (n=20) according to the method of caries removal. Cavities were prepared by the conventional drill method in group I and by hydro-abrasion in group II. Cavities of both groups were restored by self-etch adhesive (Adper Easy Bond) and nano- filled composite (Filtek Z350XT). All restorations were evaluated after 24 hours, after 9 and 12 months according to (USPHS) criteria for retention, marginal adaptation, postoperative sensitivity, marginal discoloration, and secondary caries. Results: Mild, moderate - severe and very severe pain was recorded in group I While in group II, only mild pain was recorded in (40%) of cases. The st. analysis of the collected data related to the tested USPHS criteria revealed 100% Alpha scoring regarding retention, marginal adaptation and secondary caries in both groups throughout the study period. The gap width measured under SEM was found increased sig. by time in both groups. Marginal discoloration was observed in the two groups after nine and 12 months. Post-operative hypersensitivity was found only in group I in 100% of cases at the base line and was disappeared during the next follow up period.

The authors developed a hexapod tracked mobile robot: a tracked mobile robot which is equipped with six legs attached to the robot’s body. In a transportation task, this robot can traverse a wide gap by supporting track driving with four front and rear legs while holding the target object with its two middle legs. To realize autonomous actions with this robot, we developed a two-dimensional distance measurement system using an infrared sensor. This system is very simple, with the sensor attached to a servomotor, such that it does not require high computing power for measurement. In addition, the system can be equipped at a lower cost than laser range finders and depth cameras. This paper describes the selection of the gap traversing mode according to gap width detected by the system. In this study, we conducted a gap width detection experiment and an autonomous gap traversing experiment using the hexapod tracked mobile robot with the proposed system. The obtained results confirm the effectiveness of the proposed system and autonomous traversing, which corresponds with the gap width detection.

The premixed flame propagation with conductive heat loss in millimeter-scale narrow closed cells of different gap widths is investigated experimentally and numerically. The flame evolution is obser...

The motion of firefighters during putting fires out significantly affects the protective performance of their suits. Due to firefighter’s motion, the suit moves periodically relative to the body causing a periodic variation in heat release form the suit to the body and a periodic cooling of the microclimate between the suit and the body. This paper investigated the variation in the protective performance of municipal firefighting suits as a result of firefighters’ motions. Specifically, the effect of a variation in the frequency (from 0 rps to 4 rps) and amplitude (from 0.5 mm to 3 mm) of the periodic motion of the suit relative to the body, with a mean gap width of 3 mm, on the protective performance of the suit was explored. Heat transfer through the air gaps bounded within the suit was carefully considered. The periodic variation in the thermal content of the microclimate between the suit and the body was accounted for as well. The results showed the protective performance of the suit was enhanced by the increase in the motion frequency and was worsened by the increase in the motion amplitude.

The fire whirl generated by burning a pool fire in a vertical shaft with a single corner gap of appropriate width was studied using a high-speed camera. A 7 cm diameter pool propanol fire with heat release rate 1.6 kW in free space was burnt inside a 145 cm tall vertical shaft model with gap widths lying between 2 cm and 16 cm. The flame height was between 0.25 m and 0.85 m for different gap widths. Photographs taken using a high-speed camera at critical times of swirling motion development were used to compare with those taken using a normal camera. From the experimental observations on flame swirling by a high-speed camera, stages for generating the fire whirl were identified much more accurately. Two flame vortex tubes moving over the horizontal burning surface of the liquid pool were observed. Based on these observations a set of more detailed schematic diagrams on the swirling motion was constructed. From the observed flame heights under different gap widths and using three assumptions on the variation of air entrainment velocity with height, an empirical expression relating the burning rate with flame height and the corner gap width was derived from the observation with high-speed camera. The correlation expression of the burning rate of the pool fire obtained would be useful in fire safety design in vertical shafts of tall buildings.

Background: Resin-based materials are the popular restorative material in dentistry. The majority of these materials are light cured with a major disadvantage: marginal leakage. Objective: To evaluate the gap width of different resin-based materials at the cervical dentin when achieved mechanical force. Methods: Class II cavities were prepared on extracted premolar teeth with the gingival margin 1 mm below the Cementoenamel Junction (CEJ). In the first three experimental groups, three different lining materials (flowable resin composite, bulk-fill flowable resin composite, and resin-modified glass ionomer cement) were placed at the cervical dentin with a thickness of 1 mm. The rest of the cavities were restored with conventional resin composite. The other two groups were restored with conventional resin composite (control) or high viscosity bulk-fill resin composite, respectively. All groups were thermocycled and underwent vacuum pressure 2.6 KPa for 30 min in a Scanning Electron Microscope (SEM). Results: There was no gap formation at the cervical dentin on the external surface when restored with high-viscosity bulk fill resin composite. Almost all gaps occurred at the interface between restorative materials and the hybrid layer. The flowable bulk fill resin composite showed a significantly smaller gap width on both the external and internal surfaces compared to the other groups (p< 0.05). The resin-modified glass ionomer cement showed the largest gaps in the cervical dentin (p < 0.05). Conclusion: The different types of resin-based materials demonstrated a different failure of gap width under mechanical force. It clearly occurred at the restorative material-hybrid layer interface.

Purpose In continuous manufacturing of pharmaceuticals, dry granulation is of interest because of its large throughput capacity and energy efficiency. In order to manufacture solid oral dosage forms continuously, valid control strategies for critical quality attributes should be established. To this date, there are no published control strategies for granule size distribution in continuous dry granulation. Methods In-line laser diffraction was used to determine the size of granules in a continuous roll compaction/dry granulation line (QbCon® dry). Different process parameters were evaluated regarding their influences on granule size. The identified critical process parameters were then incorporated into control strategies. The uncontrolled and the controlled processes were compared based on the resulting granule size. In both processes, a process parameter was changed to induce a shift in median particle size and the controller had to counteract this shift. Results In principle, all process parameters that affect the median particle size could also be used to control the particle size in a dry granulation process. The sieve impeller speed was found to be well suited to control the median particle size as it reacts fast and can be controlled independently of the throughput or material. Conclusion The median particle size in continuous roll compaction can be controlled by adjusting process parameters depending on real-time granule size measurements. The method has to be validated and explored further to identify critical requirements to the material and environmental conditions.

The aim of this work is studying the influence of some parameters of blowroom opening and cleaning machines on cleaning efficiency. Erect of grid gap width on waste and good fibre elimination as well as cleaning efficiency is studied for opening and cleaning machines and for blowroom line. Factorial analysis were carried out to determine if the variation in cleaning efficiency is significant or by accident. For bale opener the variables were cotton type (trash content), grid gap width and spiked lattice and evener roller selling with interaction 2 x 3 x 5. Also for cleaner RN factorial analysis were carried out for grid gap width and seed roller speed with interaction 4 x 3. Results showed that trash content and grid gap width as well as the other variables have a significant effect on cleaning efficiency. Every elimination of foreign matter is accompanied by a simultaneous elimination of good fibres. For opening and cleaning machines, as grid gap width increased trash and good fibres eliminated increased, but the rate of good fibres climination is uglier than the rate of trash climination. For blowroom line increasing grid gap width of opening and cleaning machines from narrow to open Ievel raised the cleaning efficiency from 43% to 56% and good fibres climinated increased by 30%.

Background and Objectives: Bioceramic-based root canal sealers need more evidence for proving its sealing ability. The objective of this in vitro study is to measure the leakage of extracted root canals and analyze the interfacial adaptation of the bioceramic material to canal walls. Methods: 60 extracted human lower mandibular teeth were divided randomly into 6 groups (each group 10 teeth). Group 1 and 4 were instrumented by protaper next rotary files, group 2 and 5 by wave one reciprocating files and group 3 and 6 by Two shape rotary files. All of the specimens were obturated with thermal (warm vertical compaction) technique using bioceramic as sealer. The leakage of specimens of group 1, 2 and 3 was evaluated by dye penetration method. The interfacial adaptation of specimens of group 3, 4 and 5 were analyzed using scaning electron microscopy. Results: statistics for groups 1, 2 and 3 revealed that Wave one group showed the best leakage (mean of 0.7 mm) with significant difference. By using ANOVA; Post hoc LSD test revealed that difference between groups 1 and 3 was significant, while differences between groups 2 and 1 and between groups 2 and 3 were non-significant (p

Aim of the study: The aim of this study was to evaluate the interfacial adaptation of EndoSequence BC sealer, MTA Fillapex and Vioseal sealers to root canal Dentin with and without a main gutta-percha cone. Material and Methods: Total of 60 single-rooted human teeth with single canal were selected and the crowns were removed at the CEJ level to standardize the root length (16 mm). Samples were instrumented using Protaper next NiTi rotary system up to size X5. After irrigation and smear layer removal samples were randomly divided according to the sealer used into three groups of 20 samples each, and each group was further subdivided based on obturation technique into six subgroup three group with cone and three group without cone of 10 sample each. Samples were stored for 48 hours before testing. Horizontal sections were obtained for all samples to evaluate the adaptation of sealer using Scanning electron microscope. The data were analyzed statistically by one-way Anova and Tukay’s post-hoc test. Result: Vioseal showed significantly least gap and better adaptation (P

Station batteries used as a backup source to supply station direct-current (dc) power to relays, etc., present a source of personnel exposure to dc arc flash. However, dc arc flash is less understood compared with the arc-flash phenomena that occur in alternating-current (ac) systems. Some models exist to quantify the potential hazards posed by dc electrical systems; however, there is little empirical data available. Additionally, the lower voltage and/or lower capacity station batteries are even less researched. As a result, a series of arc-flash tests were performed at the Dolan Technology Center of American Electric Power (AEP) utilizing two 125 Vdc batteries with rated capacities of 100 and 150 Ah. For these tests, working distance and gap width were used as independent variables. Upon the conclusion of testing, various relationships were analyzed to generate a predictive model for incident energy. This model serves as a compilation of the empirical data collected during testing and will contribute to future research efforts to better understand dc arc-flash incidents from station batteries.

The influence of a nonuniform distribution of the mechanical properties of rolled sheet steel on the shape of a pipe billet in making large-diameter pipes in the 1420 pipe-electric welding unit line is studied. The technique and results of measuring the hardness along the perimeter of the initial 25.8 × 4340 × 12 200 mm rolled sheet of strength class K60 are presented. The hardness of the sheet is maximal in the longitudinal direction at the tail end and is minimal at the center. The height and radius of the crimped edge are measured after crimping. The geometric discrepancy in the billet edges along the length is larger than that across the width by 6%. The horizontal and vertical diameters, the gap width, the edge displacement in height, and the diameters at l = 100 mm from the edge end are measured after step-by-step forming. The dependence of the gap width of the pipe billet after forming on the yield strength of the rolled sheet is determined.

The vertical lift gates are exposed to hydrodynamic forces that arise as a result of pressurized flow established by the large-scale effect of the water levels in the dam reservoirs. The most influential forces are those that are applied on the gate vertically upward due to the intensity of the flow under the gate and downward as a result of passage flow above the gate. The difference between these two forces generates a downpull force that is the most important gate stability indicator. In this research, an arbitrary hydraulic model was constructed to investigate the effects of many gate lip shapes with and without extensions on the magnitudes and distribution of bottom pressure coefficient when the values of flow and shaft gap width ratio (b2/bl) are constant. The results indicate that the bottom pressure coefficient appears to vary uniformly with gate openings and seem to be influenced effectively by the gate lip geometry. So, for the given value of (b2/bl), the top pressure coefficient regarding the downward force will mostly be with uniform changes and hence the downpull coefficient depends on the magnitudes and distribution of bottom pressure coefficient. An attempt by using the correlation coefficient of Statistical Package of Social Sciences was made to determine whether the pressure fluctuation is significantly shown at the bottom pressure distribution curve, which in turn is considered as appropriate indicator for the vibration occurrence. Full range of maximum bottom pressure coefficients in a matrix form is made to assist in design purposes. The results are analyzed and many conclusions are obtained.

Introduction: Physiological space is the space between maxillary and mandibular primary central incisors as well as maxillary and mandibular primary lateral incisors that occur during primary dentition period. The absence of physiological space will lead the crowded of permanent dentition due to discrepancy of the size of tooth and jaw. The objective of this study was to evaluate and analyse the prevalence of physiological space of maxillary and mandibular during primary dentition period. Methods: The type of research was a descriptive survey technique. The study was conducted at the Early Childhood Education (PAUD) in Bandung City throughout January-March 2017. The study population was children aged 3-5 years. Multistage cluster sampling used to choose subjects based on the division of the area from the city area to obtain the desired population. The data used were primary data obtained by examining the existence of a gap with a gap width indicator that is used as a benchmark of at least 0.5 mm with the help of WHO probe tool. Data were collected, processed and analysed using the SPSS (Statistical Package for Social Sciences) version 20. Results: A total of 65 out of 97 subjects had physiological space in their first dentition period. From 97 study subjects (100%) examined, 44 children (45.36%) had maxillary physiological space, and 53 children (54.64%) did not have maxillary physiological space. In 97 research subjects (100%) there were also 48 children (49.48%) having physiological space in the lower jaw, and 49 children (50.52%) did not have physiological space in the lower jaw. Conclusion: Prevalence of the maxillary and mandibular physiological space in the primary dentition period of children in the city of Bandung are 67.01%.

The study examines the degree of deviation from the nominal size of the produced open full-width mortise and tenon joint elements for their optimal pairing based on the measured thickness and gap width data. The characteristics of the measuring devices used were analysed by the repeatability and reproducibility test. The compressive strength of the single-glued joints (where only the surfaces of the tenon were glued) and double-glued joints (where the surfaces of both the mortise and tenon elements were glued) for various joint fit categories was also determined. It was found that despite the huge number of produced test specimens and their measurements, the joint fits could be maintained with the milling machine and tools. The thickness of the joint could be characterized by measuring the data at the centre of the tenon, whereas the gap width of the mortise could be characterized by measuring the data on the side of the tool leaving the wood. The double-glued joints showed higher breaking force and displacement values as compared to the single-glued joints. The joints were found to be the strongest at a tight fit of 0.1 mm.

Sample making of fractured rock mass is a big problem in rock mechanical test. The specimens prepared by traditional rock core drilling have some disadvantages such as unclear internal structure and great difference in mechanical properties; while, the samples prepared by inserting and seaming method have some other disadvantages such as hard to control the attitude of precast-joints, low accuracy. A method for preparing fractured rock-like samples based on 3D printing technology is introduced in this paper, and the seepage characteristics of fractured rock-like samples is studied by seepage experiments. Firstly, the standard profile curves of 10 grades of joint roughness are digitized and 10 groups of 3D digital fracture models are established with different roughness and thickness (i.e., 1.5, 3.0, and 5.0 mm, respectively). 30 fracture inserts are produced by 3D printing technology. Then, rock-like specimens with through-filling fractures are poured with molds. Finally, the permeability tests of the prepared rock-like specimens are carried out to study the seepage characteristics of fractures with different roughness and gap widths under different confining pressures. The results show that 3D printing technology provides an effective way for production of complex crack samples in laboratory test and the comparative analysis of tests. The seepage characteristics of fractures are well studied. When the gap width is small, the permeability decreases with the increase of roughness, and the influence of roughness on fracture permeability decreases rapidly with the increase of confining pressure and gap width. The permeability of through-filling fractures with different roughness and gap width decreases with the increase of confining pressure. The relationship between confining pressure and fracture permeability can be described by the power function. 3D printing technology overcomes the shortcomings of traditional specimen preparation methods and greatly improves the precision of crack inserts. The jointed rock-like model established by the method revealed the influence of fracture characteristics on seepage flow very well.

HighlightsUnder the same conditions of cast-iron usage, increasing the width of the gap and slat width within a certain range can enhance the bearing capacity of the slatted floors.Variations in the gap and slat width do not significantly affect pig growth performance.The recommended gap width of a cast-iron slatted floor in a fattening pig house is 15 mm.Abstract.Slatted flooring is an important part of the structure of pig houses and can aid in the removal of pig manure to underground ditches via gravity and locomotion. In this study, four different cast-iron slatted floor configurations with different gap widths (10, 15, and 20 mm) and slat widths (10 and 15 mm) were set up in 11 partially slatted-floor pig pens of the same size, each housing 10 fattening pigs with body weights of approximately 63 kg. The residual manure on the solid concrete floor area and a cast-iron slatted floor area were collected at different time intervals (24, 48, and 72 h) and weighed. According to previous studies on total manure and total urine production of pigs, the manure drainage capacity of four types of slatted floor was calculated. The growth performance of all of the pigs was monitored throughout the experiment. The ultimate bearing capacity of the four types of slatted floors was measured by a third-party professional testing organization. The results showed that the gap width and slat width of the cast-iron slatted floor had significant effects on its ultimate bearing capacity and manure drainage capacity (P0.05). The recommended gap width of a cast-iron slatted floor in a fattening pigs house is 15 mm. These findings can be used to optimize the design of cast-iron slatted flooring for fattening pigs, which must also be safe, economical, and efficient. Keywords: Cast iron, Dimensions, Fattening pig, Manure drainage, Slatted floor.

The results from simulating the operation of ozone generators based on the volume barrier dischargeprinciple with taking into account the nonuniformity of their geometrical parameters are presented. Theeffect the gas gap nonuniformity has on the barrier discharge power performance characteristics isevaluated. The results from calculating the power density distribution along an ozone generator with amonotonically varying gas gap size are presented. The power density distribution curves versus the gap width for different degrees to which the voltage exceeds its initial value are given for four types of ozone generators. New data on modeling the discharge processes in ozone generators with a nonuniform gap and on the influence of this nonuniformity on the discharge utilization efficiency are presented. The obtained results can be used in designing real ozonators, including large-capacity ones. Recommendations on selecting the optimal average gap size depending on the electrode manufacturing quality and on the gas gap setting up and adjustment accuracy are given.

It is necessary to verify an intensity-modulated radiation therapy (IMRT) plan and to confirm dose error within the tolerance, in order to perform it securely and precisely. IMRT with dynamic multi-leaf collimator (DMLC) requires high DMLC position accuracy. The DMLC position accuracy analysis software DynaLog File Viewer (DFV; Varian Medical Systems, Palo Alto, CA, USA) is used to analyze position errors of DMLC for IMRT plans. We analyzed correlation between DMLC parameters and position error of DMLC obtained from DFV in prostate IMRT. A regression analysis of the position error and the DMLC parameters was performed. As a result, a strong correlation was found between MLC position error and each of the DMLC parameters: leaf speed, gap width, and segment monitor unit (MU). We found the factors for the DMLC position error in this study. DMLC position error could be estimated from leaf speed, gap width, and segment MU when we analyze IMRT cases in the further study.

The loss of longitudinal connectivity in regulated rivers, both up- and downstream, has been detrimental for biodiversity worldwide. While progress has been made regarding upstream fish passage solutions, many questions remain unanswered regarding downstream passage alternatives. To address these knowledge gaps, we used Atlantic salmon (S. salar) smolts to experimentally assess the guidance efficiency and passage rates produced by several common screen-and-bypass fish guidance systems. Vertical screens with horizontally oriented bars extending across a turbine intake channel at a shallow angle (angled guidance screens), combined with a single, full-depth bypass entrance at their downstream end, were on average 20% more effective and produced passage rates that were 10 times higher than screens which extended perpendicularly across a turbine intake channel with vertically oriented bars that rose gradually towards the surface (inclined guidance screens) and with a bypass at the surface, on either side of the screen. Among inclined screens, gap width was negatively associated with guidance efficiencies and the smallest gap width (15 mm) exhibited a 41% greater guidance efficiency than the largest (30 mm). Among angled screens, performance was more closely linked to construction material as metal racks produced passage rates over three times faster than flexible Kevlar netting. Overall, passage through the guidance screens, and therefore into a tentative turbine intake area, was positively associated with gap width and was twice as prevalent among the inclined relative to angled guidance screens. Ultimately, an angled guidance screen with a 30 mm gap width produced the highest guidance efficiency and passage rates (a 30% improvement over the next best screen), while an inclined screen with a 30 mm gap width produced the lowest guidance efficiencies and passage rates. These results have implications for the suitability and performance of downstream fish passage solutions at both large- and small-scale hydropower plants where passage solutions are currently lacking or inadequate.

International audience; We study the effect of electron spill-out and of nonlocality on the propagation of light inside a gap between two semi-infinite metallic regions. We compare the predictions of a local response model taking into account only the spill-out, to the predictions of a quantum hydrodynamic model able to take both phenomena into account. We show that only the latter is able to correctly retrieve the correct limit when the gap closes, while the local model suffers from undesirable features (divergence of the fields, overestimation of the losses). Finally, we show that, to a certain extent, the correct results can be retrieved using a simple local approach without spill-out or a conventional Thomas-Fermi approximation, but considering an effective gap width.