Site diversity is the most effective way to recover a signal lost during heavy downpours, especially in tropical regions since other mitigation techniques such as adaptive power control and code modulation may be unreliable during such. Duplicated links at diverse sites are deployed, and the least-attenuated signal of either site will be routed to the prime site for further operation. Since the deployment is costly, a diversity-gain model is used to estimate the appropriateness of selected sites. Diversity gain is known to depend on site-separation distance and elevation angle and, optionally, baseline angle and signal frequency, based on the region of research. In addition to these factors, the horizontal rain-cell span and the wind’s impact on the gain are ongoing investigations, especially in tropical regions. This article presented the rain analysis from the year 2014 to mid-July 2017 at eight sites in the Gombak and Sepang districts of Malaysia to investigate the dependency relevancies. The rain rates were then used to predict the attenuation using the ITU-R P.618-13 rain-attenuation model, and the inter- and cross-district gain characteristics were evaluated. The observation of diurnal rain during the northeast seasons yielded that the northeast wind stimulates intense rain at locations along its direction, thus, extending the horizontal rain-cell span to 15 km distant from a host. Meanwhile, sites located at 5 km distant, slightly perpendicular to the wind direction, and from 90° to 180° from due north of the host, experience less rain. The baseline angle variation establishes nonimpact to the gain and lengthening the site-separation distance presented equal chances to the shorter span towards diversity-gain increment. The research outcome is necessary to formulate a more reliable diversity-gain model to be used in the industry. Satellite communication has been in our lives for years on our planet Earth. The existence of globally connected communication facilitates gathering information from other countries beyond the boundaries of the terrestrial network. The main issue in satellite communication appears during rainy events when the signal is degraded by the droplets, especially at above 10 GHz frequency . TherefoDiversifying the site is one of the proposed ways to help recover the satellite signal, called site diversity. The Earth station receiving the signal is multiplied and they are located at different locations from the reference site, the host. The separation distances are at least beyond the horizontal rain-cell span . The sigHodge, in his article, proposed that diversity gain be used to measure the performance of a chosen diverse site because of its practicality than the improvement factor . The gaiIn tropical regions, Jane et al. investigated seasonal variations of site diversity implementation in Nigeria . The raiSites at different locations experienced unlikely similar attenuation to the other site due to the inhomogeneity of rainfall types . The spaThis article presents the analyses of rain events from 2014 to mid-2017 (42 months) in Sepang and Gombak Districts of West Peninsular Malaysia during the northeast seasons to observe the impact of wind during the monsoon spell and the minimum span of site-separation distance that contributes to high gain. The observation is also to validate the horizontal rain-cell span proposed by Yeo et al. and indirectly determine the influence of baseline angle on the diversity gain. This investigation is essential to observe the gain dependencies of a diversity-gain prediction model. The ITU-R 618-13 rain attenuation model was used to predict the attenuation depth of the sites. The diurnal rain event was also presented to investigate the rain-type relevancy and time-series occurrences from one site to another in each district. The list of sites’ locations, the site-separation distance of each, and the model used for gain comparisons are presented in the Materials and Method section. The Results section presents the rain rate and rain attenuation CCDF graph, and the sampled rain-event duration to support the suggestion. The Discussion part elaborates on the behaviors of gain observed when pairing the site, and the impact of the northeast wind on the gain. Lastly, a conclusion was drawn.Rain gauges were used in the measurement of the rain-density readings at eight sites, four sites each in Gombak and Sepang districts. The sites chosen are located near the physical earth station (gateway) at Rawang (101.5546° E 3.30364 ° N) and Cyberjaya (101.6584° E 2.9356° N) town, respectively. In Sepang, Ladang Bukit Cheeding (LBC) is located at 101.34° E 2.51° N, Ladang Teluk Merbau (LTM) at 101.41° E 2.51° N, Paya Indah (PI) at 101.37° E 2.52° N and Puncak Niaga Selangor (PNS) at 101.41° E 2.54° N. While in Gombak, Country Homes (CH) is located at 101.31° E 3.19° N, Taman Bukit Rawang (TBR) at 101.35° E 3.19° N, Taman Desa Kundang (TDK) at 101.31° E 3.18° N, and Taman Garing Utama (TGU) at 101.33° E 3.20° N. .csv format. The rain rate of one-year readings was obtained by segregating the rain-density occurrences. Each one-minute rain value was converted to hourly form by multiplying the corresponding amount by 60; hence, the unit was in millimeters per hour (mm/h). For example, if the rain density were 0.1 mm, converting it into the rain rate would become 6 mm/h. The frequency of occurrence of each rain rate was accumulated, then divided by the total available readings and multiplied by 100 to get the percentage of time exceedances. The procedure was repeated for each year of available measurements at each site.The rain-density sampling was in one-minute intervals, recorded by the data logger at each site. The measurement was conducted by the Department of Irrigation and Drainage (DID), Selangor, Malaysia, from 1 January 2014 to the middle of July 2017, using rain gauges. The tipping bucket is 200 cm in diameter, connected to a logger to record the rainfall in 1-min time intervals. The tipping-bucket accuracy percentage is ±2% for readings of 25 mm/h to 200 mm/h and ±3% for readings of 300 mm/h to 500 mm/h. The readings were analyzed using Microsoft Excel in A at the percentage of exceedance p, denoted as The rain rates at a percentage of time exceedance 0.01% GDP=The cross-district rain events were also observed to investigate the effect of lengthening the site-separation distance on the diversity gain. The distance from each place in Gombak was measured to the areas in Sepang, with the details of their respective values shown in The gains extracted from the pair of the highest and lowest rain rate of a site diversity scheme in Sepang and Gombak were compared with four empiric gain models, the Hodge, Panagopoulos, Yeo, and Semire. These formulas were recreated using Microsoft Excel for Microsoft 365 (version 2306). The Hodge, Panagopoulos, and Semire models resemble each other in their structure except for the coefficients while Yeo is a bit different. In the former, the gain dependencies on site-separation distance, Therefore, the final predicted diversity gain, The Yeo structure of diversity-gain calculation is simpler because the frequency and baseline angle are not included as one of the factors because of the previously mentioned reason, presented in (13).f which was 20.2 GHz and the elevation angle, the d was varied according to the site being compared and so the baseline angle. The details on the sites’ parameters can be found in the Discussion section.The input for model was the same for frequency, Three parameters have been analyzed: the rain rate, the consequent attenuation, and the diversity gain of each site. Rain rates at a point of location are not the only cause of signal attenuation because a series of rain along the propagation path may accumulate the impact; however, it may be a premier source. Therefore, a correlation can be imposed that the local rain rate is directly proportional to attenuation, such that the higher the local rain rate, the higher the attenuation, as defined in the ITU-R rain attenuation model formula. Therefore, with the fixed parameters mentioned in As a result of the highest rain rates in PI, it was expected that the signal received by this site was severely impacted by the rain. Therefore, considering PI as the host, it was paired with other sites to infer the diversity gain, and the value was compared with the respective site-separation distance. The calculated diversity gains from PI to the site nearby of the same district and the site outside of the district are presented in Practically, the diverse site’s signal is only routed to the host during a certain time frame on a rainy day , especially when the host experiences heavy downpours, which causes severe attenuation and probably a signal loss. Therefore, the diurnal rain event at a specific time during the month of heaviest rain, such as November, is worth observing. As presented before, in Sepang, the site PI and LTM were receiving the highest and lowest rain rate (at 0.01 percent time exceedance), measured in two years; from 2014 to 2016. The same goes for sites in Gombak, which demonstrated that TBR and CH were receiving the highest and lowest rain rate at 0.01 percent time exceedance from 2014 to 2016. Thus, the rain rate in November of each year at the highest and lowest rain-rate sites was extracted and displayed in The rain event within the district was observed to determine the rain cell’s span. In Gombak, during November 2014 in Despite its close distance from those sites , TBR received a far lower rain rate during the same percentage of time exceedance. Therefore, the host’s selection of the nearby diverse site with less rain rate and possibly less consequent attenuation was TBR, then the CH and TGU. Considering sites at CH were also experiencing lost signal because of the high rain rate, it also needs backup from nearby sites. Hence, in the CH viewpoint, TDK experienced more signal attenuation due to its high rain rates, so it should be left unselected; thus, the nearest location with a stronger signal was also TBR. This sample showed that the rain cells are different at a site-separation distance of at least 4.14 km to the east or southeast of the host during this time.In Sepang, Hence, the November 2014 diurnal rain-event sample was analyzed in a specific time frame for each circumstance in Gombak and Sepang. Since the highest rain rate at 0.01 percent of time exceedance during this time in Gombak was TDK, its rain density in the time series was extracted. The data were taken directly from the raw source, which exhibited the timing format in 24 h with extension ‘00’ as its seconds. For example, time 3.01 p.m. was presented with ‘150100’, with ‘15’ as ‘3’ in 24-h format, ‘01’ as its minute, and ‘00’ as its seconds. From the observation of the raw data in time series, TDK received the highest rain, which amounted to 3.8 mm, on 21 November 2014. Therefore, the rain events in the time series at sites TGU, TBR, and CH were observed during the corresponding day and specific time; from 15:00 to 15:50 (50 min), as demonstrated in The distance between TGU-TBR and TGU-CH is equivalent, which is 4.14 km. However, only TGU and CH received similar rain rates, with TGU exhibiting a bit less amount of rain at each time than those in CH, while TBR experienced far less rain than both sites. Therefore, the distance between sites appears insignificant in defining the value of diversity gain. Since the observation is during the northeast monsoon, the wind might blow from the northeast of TGU with a certain spatial horizontal distance that did not reach TBR, or at least in this case below 4.14 km. This result is consistent with  which deMeanwhile, in Sepang, the highest rain rate in November 2014, which was PNS, received the peak rainfall of 2.9 mm on 5 November 2014. Consequently, the rest of the investigated areas  were observed on the equivalent day and concurrent time, which was from 15:00 p.m. to 15:50 p.m., as shown in In the meantime, PI, at 8.28 km far southwest of PNS, received a medium rainfall amounting to 0.5 mm only around 15:20 p.m. after heavy rainfall in PNS. LTM is exactly to the south of PNS and recorded nearly no rain despite being separated only 5.56 km from the latter. The PNS rain-event range at this time frame was from 15:00 p.m. to 15:50 p.m., LBC from 15:30 p.m. to 15:50 p.m., and PI from 15:19 p.m. to 15:50 p.m.; each differed in time. Hence, from the view of the PNS, it is expected that the northeast wind blow did not reach LTM. This situation is consistent with the sites in Gombak, described beforehand, that the location along the direction of the wind, including the one to the exact west of a host experiencing similar rainfall, induced by the cloud formation brought by the wind. It was observed that from the wind direction, the rain-cell extent of heavy rainfall is at least 12.96 km, consistent with the analysis by Yeo et al. in . AnotherBy referring to For the Sepang district, The rain event was extracted at a different time than the Gombak sites because the evaluation for the diverse site and rain-cell span was confined to the Sepang sites only. From Since The El-Niño brought La-Niña, a drier wind cyclone to Malaysia in 2016. La-Niña brings less of a rain amount throughout the country, even in the world. Gombak and Sepang sites showed lower rain rates at 0.01 percent time exceedance in November 2016 than in November of the years before refer to . In GombFor the Sepang sites, By observing the figure, the rain event at PI and LBC both commenced at the equivalent duration, but one with no rain and the other with a peak rainfall of 0.7 mm at 15:01 p.m., respectively. LTM experienced heavy rainfall around 28 min later than the LBC, with a peak rainfall of 2.4 mm at 15.33 p.m. The LTM rain-density graph demonstrated the downpours at this place were longer in duration, which was from 15:28 to 15:50 than at PNS which started to receive less rain at a delayed time, 15.39 p.m. onwards in this time frame. The rain rates at each site in November 2016 were a bit less than the year before, 2014 and 2015.From the abovementioned definition, determining the diversity gain requires the attenuation values of each site at a certain time percentage. Each site was paired with another to form a joint attenuation, thus construing 36 sets of gain values for three years. From the observation, a high gain was obtained when comparing sites with the highest rain rate with the lowest one. It is because the rain rate is the significant factor in determining the predicted attenuation by the ITU-R model. Therefore, to simplify the findings, sites with the highest rain rates in November of each year in Gombak and Sepang were chosen as the ones that needed a backup signal, which is the host. The remaining sites were considered diverse locations, hence the gain was calculated, as displayed in In the table, since TDK received the highest rain rate at 0.01 percent time exceedance in November 2014 than the other sites, it was considered as the host and paired with the other remaining sites within the Gombak district to construct the joint attenuation, then the diversity gain was obtained. TDK with 147 mm/h showed the highest gain; 28.24 dB when it was paired with TBR with a rain rate of 31 mm/h even though the distance between them is 7.63 km. The diversity gain obtained by pairing with CH and TGU was not much different. This is consistent with the rain event in In November 2015, TGU showed the highest gain when pairing with TDK (86.5 mm/h) of 5.24 km than other sites, with 8.96 dB; just take note that TGU to CH is 4.14 km, so is TGU to TBR. By referring to The rain-event analysis of eight sites in Gombak and Sepang reveals that the rain occurrences at a location are subject to the wind direction. In the event of heavy rain at one site, the rain-cell distance was at least 15 km long in the wind direction and at least 5 km to the east during the normal condition of a northeast monsoon. There is a circumstance where the distances are the same, but the site parallel with the wind direction received less rain than the one within the wind direction. The situation was observed at the Gombak sites during the northeast monsoon spell in November 2014, presented in TGU experienced a high rain rate during the period, and so did CH and TDK, except for TBR. The northeast-wind-caused rain may have a horizontal extent below the distance of TGU to TBR, which is 4.14 km. Hence, the location of TBR was seemingly untouched by the wind, therefore causing less rain. Meanwhile, the same prevailing wind reached CH and TDK, which are located at a similar distance (for CH) but southwest to that of TGU. The baseline orientation angle between TGU and TBR is 0°, TDK to TBR is 43°, and CH to TBR is 29.5°. This sample suggests that baseline orientation angles do not influence the gain; instead, the location of a good diverse site is at least 5 km to the east of the host, within 90° to 180° from the due north (0°), viewed on the map. This conclusion is consistent with the findings in .In November 2014, Sepang sites revealed that the least rain was experienced at LTM. Considering PNS as a host because of its heavy rain at that time, LTM was located right to its south (at 180°), as shown in During the El-Niño and La-Niña phenomena in the years 2015 to 2016, all sites were receiving higher and less rain volume than in 2014, respectively. In this case, the diversity gains are high at the diverse location farther than the host, beyond the rain-cell extent. It is because the wind is stronger than normal, bringing more moisture and forming more clouds; hence, the site nearby is also impacted by the heavy downpours. Therefore, to cater to both normal and abnormal years, the site-separation distance is suggested to be extended to 15 km away, from 90° to 180° from due north of the host. However, more data should be observed; therefore, this preliminary suggestion is valid based on the current duration of the rain event and in specific locations.For model comparisons, examples of diversity gain from the paired sites corresponding to November 2014 rain rates were compared with the Hodge, Panagopoulos, Semire, and Yeo models. The pair of PNS–LTM in Sepang was chosen because, in November 2014, PNS received the highest rain rates, while LTM was the lowest. Similar reason applied for TDK–TBR in Gombak. The details of the input used in the comparison are listed in In The rain density readings used for the research collected from DID are at least 99.9% available. The readings reported may have some mechanical issues such that the tipping bucket failed to tip during the extremely heavy rain; thus, this might cause discrepancies during data logging. Therefore, during the analysis to determine the rainfall rate at the percentage of time probability, the graph shows an indefinite value as the percentage becomes less. However, the most important thing is that the graph trend can be seen and identified refer to .This article presented a detailed analysis of the rain rate and rain attenuation at Sepang and Gombak sites, in West Peninsular Malaysia using the rain density readings of the year 2014 to mid-July 2017. The impacts of prevailing wind and El-Niño and La-Niña winds were also investigated during November, one of the months in the northeast monsoon. The analysis of the sample proposed that the baseline orientation angle does not affect the diversity gain because of the wind impact. The sites with a distance of at least 15 km to the east of the host, and in the range from 90° to 180° from its due north exhibited the higher gain. It is because Malaysia, and perhaps, countries located nearby, experience the northeast monsoon, with the northeast wind blowing clouds and consequent rain into the location of its direction, causing similar rain-induced attenuation, thus bringing lower gain to the respective host. Cross-district analysis at a site-separation distance of more than 40 km does not suggest a higher gain. Local rain may exhibit attenuation dissimilarity more than the site at far. Therefore, lengthening the site-separation distance has less impact on the gain, and the cost of the infrastructure could be decreased (in terms of underground cable if needed). The findings of this analysis could be used to reformulate the site diversity and gain empirical formulas specific to the region that is affected by the season. This work of multisite diversity performance is also beneficial in resource-sharing applications in the future.


The structure of the ice grown comprises cubic and hexagonal sequences that are randomly arranged to produce a stacking-disordered ice. We observed that ice with a high cubicity of more than 80% was transformed to partially oriented hexagonal ice when the thickness of the ice deposition grew beyond 5 μm. This suggests that precise temperature control and clean deposition conditions allow μm-thick ice films with high cubicity to be grown on hydrophilic Si3N4 membranes. The low influence of impurities could enable in situ diffraction experiments of ice nucleation and growth from interfacial layers to bulk ice.The direct observation of the structure of micrometer-sized vapor-deposited ice is performed at Pohang Accelerator Laboratory x-ray free electron laser (PAL-XFEL). The formation of micrometer-sized ice crystals and their structure is important in various fields, including atmospheric science, cryobiology, and astrophysics, but understanding the structure of micrometer-sized ice crystals remains challenging due to the lack of direct observation. Using intense x-ray diffraction from PAL-XFEL, we could observe the structure of micrometer-sized vapor-deposited ice below 150 K with a thickness of 2–50  I.The formation of ice is a complex and interesting process that plays a crucial role in various fields, ranging from microbiologyUnderstanding ice formation of ice crystals with a size in a micrometer range is especially important because they play an important role in the formation of clouds and precipitation.μm range, the direct measurement of the ice structure remains an experimental challenge.Despite the wide interest in research in various scientific disciplines, our understanding for the structure and nucleation mechanisms of micrometer-sized ice crystals is still very limited. This is partly due to the lack of appropriate experimental methods that can determine the structure of ice samples of these sizes with sufficiently high sensitivity. X-ray diffraction experiments have been used for determining the ice structure and provided valuable information about the stacking disorder structure of ices formed from supercooled liquid or vapor.μm-thick crystalline ice films grown by vapor deposition on a Si3N4 substrate surface at the temperature of 130–135 K in the ultra-high vacuum (UHV) condition. Due to the low scattering cross section of water ice, high-intensity x-ray sources, such as synchrotrons or XFELs, are required to efficiently capture diffraction data from μm-thick ice films. The ability to focus the ultrashort XFEL pulses while maintaining photon flux increases intensity, improves signal-to-background ratio, and also allows captures of crystal structures in single-shot images, avoiding contamination of the ice samples from environmental gases during data accumulation.To this end, we have utilized an x-ray free electron laser (XFEL) to observe the lattice structure of c structure) on the hydrophilic Si3N4 surface. As the ice film grew thicker by vapor deposition, the cubicity gradually decreased and the hexagonal (Ih) structure became prevalent in the film. The evolution from Ic to Ih structure appeared over the range of several μm of film thickness, which is greater than the expected decay length on the order of nanometers for the effect of substrate surface on film growth.We found that in the initial stage of the film growth, the structure of the ice sample was strongly influenced by the surface properties of the substrate, exhibiting a high degree of cubicity . A sample holder made of stainless steel was installed on the cold head through a pair of tungsten wires. The temperature of the sample holder was variable between 120 and 600 K by cryogenic cooling through a liquid nitrogen dewar and resistive heating of tungsten wires. The temperature measurement and control was achieved with accuracy less than 0.1 K using a K-type thermocouple attached to the sample holder and a Eurotherm 3504 programmable temperature controller.A 3N4 membrane as a substrate for ice deposition. Si3N4 membranes are commonly used for x-ray windows because of their excellent properties, such as high mechanical strength, uniformity, thermal stability, and high x-ray transmittance.3N4 substrates with hydrophilic oxygen termination were purchased from NORCADA. The Si3N4 membrane had a square shape with a size of 10 × 10 mm2 and a thickness of 100 nm, and it was supported by a Si frame with a size of 15 × 15 mm2 and a thickness of 500 μm. The surface of the Si frame was coated with 400 nm thick Cr/Cu for efficient heat conduction to the sample holder. The surface of the Si3N4 membrane was treated with an oxide-based hydrophilic coating of oxygen rich silicon oxynitride (SiNxOy) with a thickness less than 10 nm for efficient growth of ice film on the surface. The hydrophilicity of the oxygen-terminated Si3N4 substrate was confirmed by contact angle measurement, which revealed the angle of about 25°. The Si3N4 substrate surface was cleaned by annealing up to 600 K inside a UHV chamber to remove surface contaminants.The sample holder had a silver behenate (AgBH) calibration sample for x-ray diffraction image correction and a Si−9 Torr at 300 K. During the sample cooling, the dewar functioned as a cryopump to lower the base pressure below 2 × 10−10 Torr. The mass spectra measured with a residual gas analyzer confirmed that the gas composition inside the UHV chamber consisted only of hydrogen (m/z = 1 and 2).Experiments for ice film preparation and characterization were conducted in the UHV environment to prevent the deposition of impurities, such as hydrocarbons, that affect the ice nucleation process. Also, the deposition of additional water vapor on the sample surface was minimized during x-ray diffraction experiments. The UHV chamber was evacuated by a 250 l/s turbomolecular pump to a base pressure better than 1 × 10μm was deposited on the Si3N4 membrane by back-filling the entire UHV chamber with water vapor through a precision leak valve. Ultra-pure de-ionized water (Milli-Q) with electrical resistivity of 18.2 MΩ cm and organic carbon content less than 3 ppb was stored in a glass vial rinsed with ultra-pure H2O. The water in a vial was further purified by repeating freeze-pump-thaw cycles prior to injection into the UHV chamber. A few cycles of vapor injection to the chamber and evacuation were performed prior to the experiment so as to remove weakly bound impurity molecules from the surfaces of injection pipes and chamber wall and to replace them with H2O. After this procedure, only the mass peaks due to H2O (m/z = 16–18) could be identified, indicating that water vapor consisted more than 99.8% of the residual gas composition. Next, an ice film was prepared in the following procedure. The chamber was evacuated to a UHV base pressure, and the sample holder was cooled by liquid N2. The cooling rate was controlled less than 1 K/s by the proportional integral differential (PID) control of resistive heating to prevent thermal stress, which may crack a Si3N4 membrane. When the sample was cooled to the desired deposition temperature of 130 K, H2O vapor was introduced into the chamber and deposited on the hydrophilic Si3N4 membrane surface. An ionization gauge monitored the water vapor pressure during the deposition. The thickness of an ice film and its growth rate were controlled by adjusting the water vapor pressure and the exposure time. The film thickness was also estimated by conducting temperature programmed desorption experiments for separate samples using the residual gas analyzer as a detector. The details of the temperature-programmed desorption method have been described elsewhere.An ice film with a thickness up to 50 B.μm.All the x-ray diffraction experiments were performed at the XSS beamline of PAL-XFEL in transmission geometry. An x-ray pulse with a photon energy of 15 keV and a pulse duration of 50 fs passes through a diamond window in the center of the gate valve, connecting the PAL-XSS beamline and the UHV chamber, and is focused onto the sample surface with a focal size of 10 μm-thick vapor deposited ice film were performed with a fluence of 177.41 J/cm2 and an average exposure of 100 shots, which was confirmed as a viable condition for accurately measuring the ice structure without radiation damage. The observed x-ray diffraction images were calibrated and analyzed as follows. AgBH reference powders with well-defined diffraction peak structures were measured on the same plane to locate the center and calibrate the pixel position of the x-ray diffraction image. The momentum transfer q of each pixel was then calculated according to q = 4π/λ sin(θ), where λ is the x-ray wavelength, and 2θ is the scattering angle, from which each diffraction pattern was converted to a radial intensity profile that was solid-angle and polarization corrected. Supplementary Fig. 1 shows that from the diffraction pattern of AgBH and the distance from the sample to the detector of 32.1 cm, the center of the diffraction image observed at the detector is corrected at the expected peak positions of AgBH. In addition, in order to eliminate the x-ray diffraction background caused by the sample holder and other objects assembled in the UHV chamber, the background shot was measured with only the Si3N4 membrane under the same conditions to obtain a diffraction image without an ice film from which the background was removed. Additional analytical details can be found in the supplementary material.X-ray diffraction experiments on the III.2. Intense XFEL beams with such a strong fluence can damage the sample membrane Si3N4 and μm-thick ice films. In a previous study, when an XFEL pulse was irradiated on colloidal gold particles on a Si3N4 membrane, it was confirmed that gold nanoparticles with opposite charges were explosively evaporated by the photoelectric effect, creating holes in the Si3N4 membrane.3N4 irradiated by XFEL pulses damages not only the membrane but also the chromosome itself because the local temperature rise causes thermal expansion in a very short time due to the absorption of x-ray energy by the sample.3N4 is exposed to XFEL, it can experience damage due to several processes, including photoionization, Auger decay, and electron-impact ionization.3N4 membrane on which 10 μm thick ice was deposited. The attenuation of the x-ray pulse was varied with a Si wafer attenuator below the photon saturation limit of the detector.The focused x-ray pulse had a pulse energy of 0.6 mJ, so the corresponding fluence is 529 J/cm2 or higher, three peaks due to the ice structure were clearly observed. These three peaks coincide with the diffraction peaks of the hexagonal ice structure  and the cubic ice structure ([111]).2. In the observed x-ray diffraction pattern, it can be confirmed that the diffraction peak intensity increases as the x-ray fluence increases  peak at about 1.72 Å−1. The hexagonal diffraction patterns with [100], [002], and [101] around 1.62, 1.73, and 1.84 Å−1, respectively, are similar to the patterns discussed with ice Ic-like structures as known as stacking-disordered ice.μm of thickness shows weak peak intensity at around 1.62 Å−1, which is the corresponding [100] peak of hexagonal ice, while the peak at around 1.84 Å−1, which is the corresponding [101] peak of hexagonal ice, is almost buried by the background signal. However, the second peak around 1.73 Å−1, which corresponds to [002] peak of hexagonal ice and the [111] peak of cubic ice, is dominating compared to the other two peak structures. This implies that the 2 μm-thick ice film is composed of a large fraction of layers with cubic stacking sequences. The ice film began to decrease its cubic stacking sequences in the structure as the thickness increased further by vapor deposition. The relative intensity of peaks in the diffraction intensity profile observed at 10 and 50 μm shows that the peak around 1.73 Å−1 including [111] peak from the cubic structure is decreasing, while peaks around 1.62 and 1.84 Å−1, including peaks only from hexagonal structures, are increasing as their thickness is growing. In particular, the peak around 1.62 Å−1 grows stronger than what is expected from the theoretical intensity profile of ice Ih, indicating that the ice structure formed during vapor depositional growth has a preferred orientation along the [100] direction of hexagonal ice.The diffraction feature of stacking-disordered ice and their structural evolution during growth by vapor deposition are shown in From the structural evolution observed in the diffraction experiments, it can be seen that the cubic fraction of stacking-disordered ice decreases as the thickness in- creases, which infers that the growth process of ice by vapor deposition may have a tendency to conform to the hexagonal structure despite having a thin template with high amount of cubic structure.−1 that contains the [111] peak of cubic ice structure and peaks around 1.84 Å−1 that only contains the [101] peak of hexagonal ice structure. χ, cubicity) of 2, 10, and 50 μm-thick ice. Comparing the peak near 1.62 Å−1 from the observed diffraction pattern (blue) to the prediction with stacking disorder and no preferential orientation (dashed black), it can be seen that the ice grows by vapor deposition with the preferential orientation in the hexagonal [100] direction. In addition, the cubic fraction decreased from 80% in 2 μm-thick ice to 20% in 50 μm-thick ice, implying that the ice structure progresses from a structure with high cubicity that includes a large fraction of cubic sequences to an ice structure with low cubicity with the majority of layers composed of hexagonal sequences when ice is grown through vapor deposition.The quantitative analysis of stacking disorder ice using DIFFaXμm-thick ice can be interpreted as a hydrophilic property of the Si3N4 membrane affecting the ice nucleation process to initially have a preferred structure of cubic sequences. As the surface effect diminishes, the grown ice transforms into structures with hexagonal sequences due to screening by the water ice layers. In fact, new ice layer deposition in micrometer-thick ice films occurs at the ice–vapor interface, which is far from the hydrophilic Si3N4 membrane surface so the surface effect became negligible at the ice nucleating layers. Previous studies about the ice structure near hydrophilic and hydrophobic structures report that only a few interfacial layers of ice show the highly ordered cubic structure and it became the preferred hexagonal ice structure in the sub-nm to few nm range.The observed structural progressions of μm, so the temperature effect on cubic-to-hexagonal structure evolution is negligible in this regard.Another possible explanation of the structural evolution is that the temperature at the ice–vapor interface where new ice layer nucleation occurs gradually increases so that the hexagonal ice structure is favored. Many previous studies show that ice nucleation by vapor deposition prefers cubic sequences below 130 K and gradually transforms to prefer hexagonal sequences when temperature increases up to 180 K, because at low temperature ice does not have enough energy to transform from metastable cubic phase to thermodynamically stable hexagonal phase.N + 1)th ice layer, Nth ice layer can be expressed asMany previous studiesD = NIn this study, we are interested in the average value of the cubic ice fraction, μm, which cannot be seen from previous experiment on nm-scale interfacial ice structure and mm-scale bulk water ice structure. This model could explain relatively long-range cubic-to-hexagonal structural evolution as the ice is initially nucleated into a highly ordered structure with high cubicity by a strong surface effect; although the surface effect is diminished in the nm range, the cubic structure gradually decreases through growing as stacking-disordered ice by vapor deposition.As shown in c on hydrophilic surfaces in extraterrestrial environments.Moreover, this finding implies that ice in extremely low impurity environments has long-term surface effects on formation and structural properties due to depositional growth at the water vapor interface. This unique crystallization process hints at a possible mechanistic pathway for the formation of ice IIV.μm-sized ice films was observed by the help of intense x-ray diffraction experiment in transmission using the PAL-XFEL. Ice deposited on the Si3N4 membrane by vapor deposition under UHV conditions can be used to control the film thickness and avoid the influence of impurities on the nucleation process. This enables us to capture the structural transition from a highly cubic ice structure to a hexagonal ice structure during the growth mechanism, as new layers of ice are deposited on the μm-scale when ice crystals are nucleated and grown by vapor deposition. Also, intense XFEL diffraction has enabled us to observe the structure of μm-thick ice films for which relatively long-ranged cubicity decreases as the ice film grows. This cannot be observed by experiments that focus on interfacial ice structures using electron diffraction and bulk ice structures using reflection-type x-ray diffraction experiments. The single-shot x-ray diffraction experiments on μm-thick ice films deposited on Si3N4 membrane show the possibility of the in situ type of diffraction experiments on ice nucleation and growth from the interfacial layers to bulk ice. While we have explored the structure of ice that is already grown as μm-thick films, further studies will fully explore the structural evolution of ice from the initial nucleation stages to growth process by vapor uptake, which could form under clouds at high altitude or in deep space. In particular, it would be valuable to study ice grown from different initial states and conditions, by varying, for example, the surface and temperature. In addition, studies using specific surfaces that promote or prevent ice nucleation could elucidate how to control the structure of ice nucleation in different environments and can be used to model the global climate in depth.In this study, we investigated the structure of micrometer-sized vapor-deposited ice films crystallized at low temperatures, relevant for cold clouds in the stratosphere and high troposphere, cryobiology, and protostars. The ice films have a stacking-disordered ice structure with large cubicity that decreases as the film thickness grows by vapor deposition. The crystalline structure of the


The plastication of pellets in a co-rotating twin-screw extruder is a significant concern for product homogeneity and stability in the plastic industry. We developed a sensing technology for pellet plastication in a plastication and melting zone in a self-wiping co-rotating twin-screw extruder. The collapse of the solid part of the pellets emits an elastic wave as an acoustic emission (AE) that is measured on the kneading section of the twin-screw extruder using homo polypropylene pellets. The recorded power of the AE signal was used as an indicator of the molten volume fraction (MVF) in the range of zero (fully solid) to unity (fully melted). MVF decreased with increasing feed rate monotonically in the range of 2–9 kg/h at a screw rotation speed of 150 rotations per minute (rpm) because of the reduction in the residence time of pellets in the extruder. However, the increase in feed rate from 9 to 23 kg/h at 150 rpm resulted in an increase in the MVF as the friction and compaction of pellets caused their melting. The AE sensor could elucidate the pellet’s plastication phenomena caused by friction, compaction of pellets, and melt removal in the twin-screw extruder. Co-rotating self-wiping twin-screw extruder is a continuous polymer processing machine and one of the most widely used screw extruders in the polymer processing industry. It produces pellets, sheets, films, and other plastic products efficiently. The twin-screw extruder transports, plasticates, and melts pellets of plastic resin. When pellets of thermoplastic resin are fed to the twin-screw extruder, the heat transfer from the barrel of the extruder, friction, and adiabatic compression of pellets result in plastication and melting of pellets . If the The plastication and melting of pellets in a co-rotating twin-screw extruder have been studied mainly by building mathematical models and performing numerical simulations of the plastication zone over the past three decades ,3,4. TheReal-time monitoring can raise the alarm and eventually stop the line when the pellet plastication is insufficient. It readily provides the state of pellet plastication and helps understand the phenomenon. However, the resin temperature and pressure sensors are too fragile to be used in the solid pellets and plastication zones as the solid pellets may collide with the sensors and damage them. Hence, a new type of sensor for resin plastication monitoring is demanded. In this study, we focused on acoustic emission (AE). AE originates from the transient stress waves that are generated by crack growths and many other kinds of material degradation and deterioration . AE can According to the previous studies on applying AE sensing to various materials, we can expect that collapsing resin pellets in the kneading screw elements emit the AE signal in the extruder.The AE sensor comprises a piezoelectric transducer and detects ultrasound waves as the AE signal. The ultrasonic wave receiver and transmitter have been applied to the extruders in polymer processing to evaluate the density of polymer melt and the composition of polymer blends . PreviouHere, a measurement technique to monitor pellet plastication in the extruder using an AE sensor was developed. The effects of screw speed, flow rate, and plastication of polypropylene pellets in the twin-screw extruder were investigated. The experimentally obtained data were discussed with the suggested mechanism previously reported by Gogos et al. .A homo polypropylene  with a melt flow rate (MFR) of 7.0 g/10-min was acquired from Prime Polymer, Minato City, Tokyo, Japan. The resin was used as received. The parameters of the Cross model fitted to the complex viscosity are shown in the ® software was used to collect and record the AE data. The data acquisition speed was 250 kHz, and the sampling period was 0.2 s.An AE sensor , a built-in amplifier, a 2nd amplifier (EDGE NODE DISCOVERY SEG), and a data acquisition A/D converter  were connected sequentially. In-house LabVIEWThe AE sensor was attached to a waveguide with a diameter of 17 mm and a length of 300 mm screwed on the barrel of the twin-screw extruder, as shown in A co-rotating self-wiping twin-screw extruder : It is a simple screw configuration in which one kneading disk element is at 977.5 mm from the feed, and the others are full-flight screw elements, as shown in Configuration (B): The screw configuration (B) was built to understand the effects of feed rate and screw speed on the plastication phenomena in a full-flight screw, as shown in Two series of experiments were performed. In the 1st series, the screw rotation speed was increased while the feed rate was maintained constant. Subsequently, the process was examined at a higher feed rate from low to high screw rotation speed. In the 2nd series, the feed rate was increased while the screw rotation speed was maintained constant.In addition, to collect the AE signal of fully solid pellets for the normalization of the AE signal, the barrel temperature was set equal to the melting temperature at 164 °C.Configuration (C): The screw configuration (C) was considered to understand the effect of kneading disk elements on the plastication phenomena, as shown in The mean residence time of the solid pellets on the full-flight screw was measured as follows. The screw configuration was as same as the upstream configuration from the AE sensor of (B) in The barrel temperature was set to a room temperature of 30 °C. The pellets were fed to the rotating twin screws alone, consisting of full-flight screw elements and no kneading disk elements. The exit of the extruder was open, and no die was attached to it. This operation does not collapse and melt the pellets. The pellets were only transported to the exit of the extruder by the rotation of screws.mp) was measured. The mean residence time per meter was calculated as follows:mp (kg) is the remained mass of pellets in the barrel when the screws stopped, Qm (kg/s) is the pellets’ mass flow rate in the feeder, and Lm (m) is the measured barrel distance, which is 0.918 m from feed to head.In the measurement operation, the rotating screws and the feeder of pellets were abruptly stopped when the mass flow rate reached a steady state of the desired value. The screws were rotated again to transport the remaining pellets in the barrel when the feeder stopped. All the pellets in the barrel were collected, and the mass  at the screw rotation speed and feed rate of 50 rpm and 2.0 kg/h, respectively. The pellets collapsed between the barrel and screws. The pellets were fully melted, and a clear molten strand was obtained at the exit of the die at the barrel temperature of 195 °C at the same screw rotation speed and feed rates at 30 °C.A typical time domain and the fast Fourier-transformed AE signals obtained at the barrel temperatures of 30 °C and 195 °C are shown in A model of AE signal generation, as illustrated in χp, is calculated as follows:S is the accumulated signal per pellet. S is the reference signal. We could not use the data at room temperature, i.e., at 30 °C, because the pellets could not pass through the three kneading disks, and the motor’s torque increased the specification value. The pellets extruded at Tm (164 °C), 2 kg/h, and 250 rpm seemed almost solid and did not stagnate in the kneading disk elements. The further increase in feed rate and/or screw rotation speed caused the torque-over. When the only kneading disk, such as in the case of screw configuration (A), was used, the torque-over did not occur. However, some solid pellets passed through the one-kneading disk zone without collapsing. Hence, we placed three kneading disks to ensure all the pellets collapsed in the kneading zone.Finally, the MVF, A1 = −0.434, t1 = 5.79239 (s/m), y0 = 0.99309. The plots on the correlation line and deviated plots indicate that our definition of MVF of Equation (2) is less sensitive to lower MVF and high solid content. Further study is required for the appropriate definition of MVF. Interestingly, the MVF curves at 50 rpm and those at 100 rpm are different in The effect of the kneading disk was investigated by replacing the full-flight screw with the kneading disk (configuration (C)). Plastication of semicrystalline resin pellets in a twin-screw extruder was investigated using the newly developed AE sensing system, which detects the elastic wave and prevents the collapse of the partially melted pellets in the twin extruder. The MVF based on the power of the AE signal per pellet was defined. The feed rate and screw rotation speed affected the MVF nonlinearly. The residence time, accumulation of pellets, friction between pellets, and compaction play significant roles in plastication. Their contribution changes according to the feed rate. Moreover, the kneading disk efficiently enhanced the plastication independent of the feed rate. The compaction of pellets in the kneading disk zone is a significant factor in plastication.Measurement of plastication using AE sensing has several advantages. The AE sensor does not contact an object directly. The AE sensing can be applied to severe situations in pressure transducers and will detect abnormal plastication via a sudden increase in the AE signal. The AE sensing and investigation of plastication still have some limitations. Our AE sensing data support the previously proposed plastication mechanism. However, further quantitative analysis with mathematical models, such as finite and discrete element methods, is required. Moreover, plastication is followed by mixing additives, resin, and glass fibers in a typical extrusion process. Therefore, it is necessary to identify and categorize problems arising from mixed signals of glass fiber breakage, inorganic particles, and the blending of different viscoelastic materials.


QX-like infectious bronchitis virus (IBV) is a highly infectious avian coronavirus that causes respiratory and kidney disease. It is linked to increased mortality and loss of performance in infected chickens worldwide, including Thailand. Thus, a simple and rapid diagnostic method for the diagnosis of QX-like IBV is needed. This study aimed to develop a single-step multiplex reverse transcription-polymerase chain reaction (mRT–PCR) assay to detect and differentiate QX-like IBV from Thai IBV and vaccine strains used in the poultry industry .Primer sets specific for QX-like and Thai IBV were designed to target the S1 gene. The specificity of the technique was verified using nine isolates of QX-like IBV, four isolates of Thai IBV, and other avian viral respiratory pathogens. The detection limit was evaluated using a serial ten-fold dilution of QX-like and Thai IBV.2.2 embryo infectious dose (EID)50/mL for QX-like IBV and 101.8 EID50/mL for Thai IBV. Interestingly, the developed assay could identify mixed infection by both IBVs in a single sample.The results showed that single-step mRT–PCR could detect QX-like IBV and differentiate it from Thai IBV and the vaccine strains H120, Ma5, and 4/91. The limit of detection of the developed assay was 10The single-step mRT–PCR assay developed in this study can potentially discriminate QX-like IBV from Thai IBV and the vaccine strains H120, Ma5, and 4/91 in a single reaction. It is also suitable for use in all laboratories with access to conventional PCR equipment. Gammacoronavirus and family Coronaviridae [st time in 1996 in China [Infectious bronchitis (IB) caused by IB virus (IBV) is considered endemic in poultry-producing regions worldwide. Infectious bronchitis causes significant economic losses in the poultry industry due to increased mortality in infected birds. Infectious bronchitis virus belongs to the genus aviridae . In receaviridae , 3, whicaviridae . The QX aviridae , which win China , 7. Infein China . In addiin China .Vaccination is routinely used in commercial chicken farms to prevent economic losses from IBV infection. However, there is a low level or no cross-protection against IBV strains , 10. BecThis study aimed to develop a single-step mRT–PCR assay to detect and differentiate QX-like IBV from Thai IBV and vaccine strains used in the poultry industry .Ethical approval is not needed to pursue this type of study.This study was conducted from January 2021 to June 2022 at the Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, Thailand.® IB Ma5, MSD Animal Health, New Jersey, USA), and 4/91 (Nobilis® IB 4/91) were included in this study.Nine isolates of QX-like IBV and four isolates of Thai IBV used in this study were confirmed via RT–PCR and S1 gene sequencing as described previously . They wePrimer sets specific for QX-like and Thai IBV were designed to target the S1 gene. Primers F55N2-TGA TTG ATA CTG CCA GTA AT and R436-ACA ATG TGT GAC AAA CAG TG, amplifying a 271-bp product, were used to detect QX-like IBV. Primers F173-CGC AGG TGG TTC CTC TGA AT and R436-ACA ATG TGT GAC AAA CAG TG, amplifying a 158-bp product, were used to detect Thai IBV. The primer sets used to amplify all IBV strains included GU391-GCT TTT GAG CCT AGC GTT, according to a previous report [Viral RNA was extracted from 200 μL of allantoic fluid using Viral Nucleic Acid Extraction Kit  following the manufacturer’s protocol. The resulting RNA was dissolved in 50 μL of nuclease-free water. Single-step RT–PCR  was performed according to the manufacturer’s instructions. The reverse transcription was performed at 48°C for 45 min followed by 94°C for 5 min. The PCR program consisted of 35 cycles of 94°C for 30 s, 56°C for 30 s, and 72°C for 30 s, followed by a 10-min extension at 72°C. Reverse transcription-polymerase chain reaction products were analyzed on a 2% agarose gel containing RedSafe Nucleic Acid Staining Solution . The gels were run at 120 V for 45 min and visualized using a Gel Doc™ XR+ Gel Documentation System .6.2 to 100.2 embryo infectious dose (EID)50/mL and the Thai IBV isolate THA90151 ranging from 106.8 to 100.8 EID50/mL. Each dilution of the virus was also tested after isolation from embryonated chicken eggs. The limit of detection of virus isolation was set as the first dilution at which no embryo mortality or lesions were observed.To determine the limit of detection of the developed single-step mRT–PCR assay, it was performed using ten-fold serial dilutions of the QX-like IBV isolate THA80151 ranging from 10The specificity of the assay was tested using nine isolates of QX-like IBV; four isolates of Thai IBV; and the vaccine strains H120, Ma5, and 4/91. Other avian viral respiratory pathogens were also tested, including Newcastle disease virus (NDV) and infectious laryngotracheitis virus (ILTV).To evaluate the ability of the developed assay to detect mixed IBV, RNA from THA80151 and THA90151 was mixed at equal volumes and tested using the developed single-step mRT–PCR assay.As shown in Figures-2.2 EID50/mL (10−4 dilution) for QX-like IBV and 101.8 EID50/mL (10−5 dilution) for Thai IBV (1.2 EID50/mL (10−5 dilution) for QX-like IBV and 100.8 EID50/mL (10−6 dilution) for Thai IBV.QX-like and Thai IBV were detected and discriminated based on the expected bands. No bands were detected when ILTV was tested in this single-step mRT–PCR assay. Unexpected bands were generated after NDV amplification, but they did not correspond to the bands obtained for IBV . The limThai IBV . FurtherCurrently, QX-like IBV is the predominant genotype of IBV in Thailand . The sprGallid alphaherpesvirus 1), and the RT–PCR product generated for NDV was inconsistent with that generated for IBV. These findings indicated that the developed single-step mRT–PCR assay was specific for IBV. The limits of detection of the developed assay were 102.2 EID50/mL for QX-like IBV and 101.8 EID50/mL for Thai IBV. Although the limits of detection of the developed assay were higher than those of virus isolation, they were similar to the detection limits of real-time mRT–PCR assay for the classical (G1) and Egyptian variant II (G23) IBV strains. According to a previous study [50/mL for both genotypes. Our study suggested that this single-step mRT–PCR was a rapid and sensitive assay for discriminating QX-like and Thai IBV. Moreover, it was a useful method for the diagnosis of QX-like and Thai IBV infection in chicken flocks vaccinated with H120, Ma5, and 4/91.The single-step mRT–PCR assay developed in this study could simultaneously detect and differentiate QX-like IBV from Thai IBV and the vaccine strains H120, Ma5, and 4/91 in a single reaction. Furthermore, the developed assay could detect mixed IBV in a single sample, as specific RT–PCR products were obtained for the two viruses. The specificity of the developed assay was also tested using other viral respiratory pathogens. No RT–PCR product was generated for ILTV . In addition, the method discriminated QX-like IBV from other avian viral respiratory pathogens. Hence, the single-step mRT–PCR assay developed in this study can be used as a diagnostic assay for detecting QX-like IBV, and it is suitable for use in all laboratories with access to conventional PCR equipment.TP: Conceptualization, supervision, and project administration. SJ and TP: Methodology, data analysis, writing, reviewing, and editing. All authors have read, reviewed, and approved the final manuscript.


Ice hockey is a complex sport requiring multiple athletic and technical attributes. Considering the variety of tests developed, on-ice testing protocols have been created to measure the physiological and mechanical attributes associated with performance. To our knowledge, a lack of technical resources exists to help stakeholders opt for on-ice protocols from among those developed. It becomes crucial for researchers and practitioners to select relevant and context-specific procedures. This systematic review of the literature outlines an inventory of the on-ice tests that have been used in the domain of ice hockey research over the last twenty years, and summarize protocols mostly used in major athletic components.A search was performed on three databases  by following the PRISMA guidelines. Specific keywords were selected to find publications using on-ice testing protocols in the methodology. Four aspects of athletic attributes were used to categorize the protocols: aerobic capacity, acceleration-speed, agility-change of direction and ability to repeat skating sprints. Analyses were conducted regarding four categories of observations: population under study, on-ice reported test(s), outcomes measures and main findings.n = 7), acceleration-speed (n = 6), agility and change of direction (n = 23) and repeated skating sprint ability (n = 19). Testing in male and older cohorts (≥16 years old) predominates, with a primary focus on the competitive amateur level. The selected tests were mainly designed for assessing on-ice physiological responses and fitness (n = 38), talent identification-team selection (n = 19), efficiency of interventions (n = 17) and validation purposes (n = 16).A total of 107 articles were included, resulting in 55 on-ice tests related to the on-ice assessments of four major athletic components: aerobic capacity (A prevalence of on-ice skating tests to assess the ability to repeat intense efforts, agility, acceleration and speed components exists, which are relevant and linked to match requirement. The wealth of on-ice tests used in the literature reflects the need to adapt the on-ice evaluation process to the population, constraints, and goals. This review is a valid toolbox and can benefit for researchers and practitioners interested in testing hockey players from different levels, with a variety of aims and needs, by helping them to select the relevant procedures to their environment and practice context. As an i1.1.Performance in ice hockey is assessed from three main scientific perspectives: off-ice fitness or athletic capacities , on-ice in situ assessment, where it becomes possible to measure and track players' instantaneous on-ice performance during in-game situations. Previously analyzed with traditional methods   , 35, tecn grids) , 37, 38.In summary, we can conclude that two performance-assessment approaches coexist in the domain of ice hockey: “off-ice” fitness tests and specific “on-ice” tests. As mentioned previously, given that off-ice tests may not be specific enough to the requirements of ice hockey, increased attention to on-ice assessment seems to offer the path to a better understanding of the mechanisms underlying performance in ice hockey . In this1.2.When seeking the most reliable and valid options for testing hockey players, researchers face multiple options regarding the best ways to assess the attributes needed to excel. Regarding a major specificity of this sport, there is currently no exhaustive literature review, to our knowledge, of on-ice test protocols used with specific populations and different levels of expertise. From this perspective, bridging the gap between science and its application in practical settings  is relevant for both researchers and practitioners. For researchers, an in-depth knowledge of the methods used to assess ice-hockey attributes, with regard to strong external validity, is valuable in their search to replicate research designs specific to the populations studied. More practically, a complete repertoire of on-ice testing protocols is relevant for ice hockey and strength and conditioning coaches as well as federations because it allows them to select methods that are appropriate and adapted to their players' characteristics . Accordingly, the aim of this systematic review is threefold: (1) to present an inventory of the on-ice testing protocols most frequently used to assess physiological and physical attributes relating to ice hockey; (2) to provide a critical overview of the characteristics used in this research including population under study , study design; validation; and outcomes measures, and (3) to propose recommendations for research-practitioners on the methods that were used in their areas of interest. These recommendations will serve as a framework for designing replicable designs  and/or implementing testing sessions adapted to stakeholders' purposes .2.2.1.How many on-ice tests are mentioned in scientific research that aim to assess the physical, technical and physiological qualities of hockey players?” Next, it describes the population, type of study design and observed associations of the different tests in order to identify current contributions and related scientific shortcomings in the field of ice hockey. As mentioned earlier, the main objective of this review is to inform researchers of what has been done in on-ice performance testing and provide measurement tools for practitioners to assess hockey players.The systematic review process is a suitable and appropriate method to quantify several studies with different designs, establish links between them and synthesize them . This ty2.2.ice hockey and test* as keywords for all databases searched. Searches were limited to articles in English published since January 2000. We justify this time frame for many reasons. Firstly, the introduction of professional (NHL) players at the 1998 Nagano Olympics contributed to the globalization of ice hockey, which resulted in an increase of scholars' interest towards the science of ice hockey. The profile of modern ice hockey players also changes over the years. For example, an article published by Triplett and colleagues . Next, we added articles published from August 2022 to May 2023 as well as articles which were not in the databases mentioned above but which corresponded to the inclusion criteria. Endnote  was used and, after all titles of the three databases were uploaded, the software automatically identified and removed duplicates. Relevant articles were then screened for eligibility after reading the title and abstract of each remaining record, following the same manual PICOS procedure strategy  as for the database search and inclusion criteria .2.3.Two researchers (MB and GM) independently screened the title and abstract for each selected record by applying the PICOS framework. Inclusion criteria were: (1) male and/or female ice hockey players; (2) any articles containing at least one on-ice hockey test; and (3) ice hockey on-ice test that evaluates aerobic capacity, speed, agility or change of direction and ability to repeat sprints. Exclusion criteria for eliminating irrelevant records were: (1) article was not written in English; (2) test was not performed on the ice; (3) testing procedure was not clear ; and (4) there were no test assessing attributes other than those mentioned above . After completing these steps, the researchers read each eligible article in full to narrow the list to all relevant studies that answered the research question. If the evaluating authors disagreed about the inclusion of an article, the decision was made by a third researcher (JL), also after reading.2.4.Based on ice hockey game performance analysis , 4, 48, 2.5.For each study retained, we recorded the population's age (mean), sex, level of play and geographic location. For the mean age, the standard deviation was not considered for classification into the four age groups, which were categorized based on the Long-Term Athlete Development model (LTAD) : (1) und2.6.Types of associations were analyzed to specify the context in which studies were conducted and were classified based on selected studies' outcomes measures: physiological variables, talent identification, training effects , validation, test parameters, off-ice testing, and other measures . The authors noted three categories of research designs: observational, (quasi) experimental and validation studies. Researchers gathered all information by formatting an Excel document to include these details. They then extracted the information by attributing a numeric code to each article to classify and analyze the distribution of each type of study.3.3.1.n = 394), SPORTDiscus (nn = 439) and Scopus (n = 671). The combined database search yielded 849 titles after removal of duplicates, and 18 studies were added manually (n = 7), skating acceleration and speed (n = 6), agility-changes of direction (n = 23) and repeated skate sprint ability (n = 19).manually . Analysi3.2.3.2.1.3.2.1.1.n = 59) and those 16–19 years (n = 39). Players under 12 years and 12–15 years old were less tested . Specific to the categories of athletic attributes, older cohorts  were most frequently assessed for on-ice acceleration-speed and ability to repeat skating sprints. Conversely, younger groups of athletes  were mainly tested on skating agility and on-ice acceleration-speed attributes.For the populations studied, the age groups most frequently tested in the scientific literature included players over 16 years old, divided into those over 20 years (3.2.1.2.n = 95) compared to females (n = 27), for each tested attribute. Some differences were observed according to level of play, where results indicate that the literature focused more on amateurs (n = 58) than youth or professional level players (respectively n = 37 and n = 22). On-ice speed tests were mainly administered among amateur cohorts (n = 33), youth assessment focused more on speed and agility components , and professional athletes were tested in similar proportions on all physical attributes.Regarding sex, males were by far most frequently tested (3.2.1.3.n = 57) compared to Europe (n = 49), and only two studies were carried out in other countries .Results show that geographic location was well distributed. More on-ice evaluations were conducted in North America (3.2.2.n = 69), while experimental and validation protocols were less frequent (respectively n = 22 and n = 16). These results are similar when the focus shifts to each specific attribute, with a primary focus on on-ice acceleration and sprinting qualities over other attributes.Most of the research done in on-ice hockey testing consisted of observational studies (3.2.3.n = 38). Below, talent identification, training effect and validation are subsequent outcomes showing similar proportions . Then, test parameters, off-ice testing and other studies objectives were implemented in the same ratio . On-ice acceleration and speed components along with agility were the two major athletic attributes assessed in the focus on on-ice testing in hockey research.Results demonstrate that the main objective of research conducted in ice hockey on-ice assessment relates to physiological variables (3.3.3.3.1.3.3.2.n = 12), were male (n = 21) and played at the amateur level (n = 11). No studies were found on the on-ice aerobic capacity of ice hockey players under 12 years old. Additionally, four studies assessed on-ice aerobic capacity in female ice hockey players. Two of these were designed to test validation, while the others discussed the differences in the physiological parameters of males and females during graded exercise (n = 4) and 20 years+ (n = 3). Athletes from the amateur and professional levels were most often tested for aerobic capacity. These studies focused almost exclusively on male players (n = 9).A total of 21 articles were found including tests of on-ice aerobic capacity in ice hockey players. The authors listed seven different tests where the majority of studies involved ice hockey players who were 20 years and older , followed by backward acceleration, backward sprint and full speed. As for skating distances, the most frequently applied protocols are the 6.1 m forward skating sprint test for on-ice acceleration and the 30 m for on-ice forward speed. All these are applied progressively for age cohort groups, with a prevalence among older athletes . From a level of play perspective, more tests were conducted at the competitive amateur level (n = 33) than at the youth (n = 26) or professional (n = 13) levels. This athletic attribute was more often assessed in North America than in Europe .There are 66 articles in the present review, corresponding to six tests to assess on-ice acceleration and speed components in ice hockey. Forward acceleration or sprint are the most commonly used protocols (respectively 3.3.4.n = 42) aged 20 years and older (n = 23) playing at a competitive amateur level (n = 20). Only two studies were found regarding the assessment of agility in young ice hockey players under 12 years old. This on-ice attribute is assessed as much in North America as in Europe , while Asia has one study. On an individual basis analysis, the Cornering S turn is the most frequently used on-ice test (n = 12) and implemented in both sexes. This protocol is well documented in the literature across the age ranges of 12–15, 16–19 and 20+ years old  and is similarly represented in all levels of play .On-ice agility and change of direction tests appeared 47 times in scientific publications. A high variability is observed in the selection of this category of tests, since 23 tests were found to evaluate this athletic quality, 17 of which appeared less than three times. Furthermore, there is a considerable gap in the literature regarding validation of agility tests, since only one test, the specific overall skating performance test (SOSPT), was validated over the timeframe of this review. The use of agility testing across the different studies was mostly targeted to male athletes (3.3.5.n = 34) in an older population  compared to younger cohorts  playing at a competitive amateur level (n = 22). From an individual perspective, the Reed test appears to be the most conducted test (n = 6), while others  follow below (from n = 5 to n = 3).Ability to repeat on-ice skating accelerations, sprints or intense effort tests are well documented in ice hockey assessment, with 41 articles corresponding to 19 different on-ice protocols. A substantial and similar variability in agility is also observed in the selection of this category of tests, since 13 of the 19 tests occurred less than three times. In the various studies, tests of skating sprint repetition ability involved mainly male athletes (3.4.r = 0.97) and reliable (r = 0.92) ( = 0.92) . Acceler = 0.92) . The cor4.The general aim of this systematic review was to describe the extent to which evaluation protocols for different populations of ice hockey players have been used over the last twenty years. To this end, we identified four key categories of attributes related to ice hockey performance: aerobic capacity, speed, agility and ability to repeat intense efforts or sprints. Despite researchers' efforts so far to document the usefulness of assessing hockey players , this reRegarding the populations studied and their attributes, it is interesting to note that the inventory of on-ice tests offers observations consistent with the attributes observed, as illustrated in n = 7 and 6), with a majority of them that have been validated and used in most research, in a logical manner. Conversely, a large variability has been highlighted in CoD-agility and ability to repeat skating sprints attributes, with a wide range of tests (respectively n = 19 and 23) developed to assess theses capacities in ice hockey athletes. Assess capacities as CoD, agility and RSSA in a specific ecological perspective on the ice has some issues in contrast of aerobic or speed qualities, which seems to be easier to standardize.As for test reliability and validity, results reveal that most of the protocols move in two opposite directions. First, the inventory proposed by our review suggests that most of the tests have very satisfactory levels of reliability and validity, at least with the populations studied using these protocols. Examples include the SMAT, 30-15 IIT, Yo-Yo IR, forward skating acceleration and sprint, cornering-S turn agility test, or even some ice hockey-specific repeated sprint tests such as the 7 × 15 m or the SOSPT. Another considerable part of these tests, however, has not been validated or replicated through an objective scientific process. This is mainly the case for tests targeting agility or ability to repeat intense skating efforts. Given their relevance, particularly for assessing the development of young talent, it is vital to identify and develop specific standardized, reliable and valid on-ice protocols to maintain qualitative analysis and optimal procedures to track progress and enable comparisons. Despite the lack of scientific insight, there is a definite advantage to assess in a sport-specific context that resembles a real game as closely as possible if the test is designed consistent with sport requirements , 104. AsMost of the tests considered in this systematic review do not include the puck in the assessment, as described in This review also reveals that female players has so far received very little attention in the field of on-ice testing compared to their male counterparts. Considering the different physical capacities and the different role they can play in the selection process for female athletes, a more specific focus on the development of tests specific to female hockey players could offer some interesting advancements . In otheRegarding level of play, our results indicate that most studies focus on the amateur sphere, with less attention paid to professional and youth levels. Data sensitivity at elite levels limits the possibility of evaluating athletes for research purpose, information is confidential and restricted to staff members who cannot communicate results because of privacy data protection. At youth levels, however, a plausible explanation could be that the development of technical on-ice skills takes priority over evaluation when an athlete lacks the necessary technical prerequisites, making evaluation needless. Our analysis reveals that most studies of on-ice performance evaluation are descriptive. This is understandable considering it's easier to observe trends, relationships and correlations than to conduct more in-depth studies within structures, clubs and federations . Moreover, on-ice evaluation batteries are intended for formative or selective purposes.4.1.The inventory proposed by this review helps identify the avenues to explore for a more enlightened view of the (evolving) status of ice hockey players worldwide. For researchers, it is a relevant guide that allows studies to be replicated based on the characteristics or variables being studied. An inventory of on-ice tests also gives researchers an indication of the populations under study. The tool enables teams' coaches to make informed choices that will facilitate analysis and interpretation of the standards achieved by the populations under study. Coaches can also use on-ice testing by integrating it as a drill during practices to develop each attribute in a high pace manner. For example, agility test ended by a shot can be used at the start of practice to develop skills and agility to mimic game specific situations. Another option might be using RSSA test at the end of the practice and include several shots during each recovery time to develop the ability to perform and maintain precision shots despite fatigue and enjoying more the conditioning aspect of the drill. For strength and conditioning coaches, the assessment of all four areas of physical attributes is relevant for designing adapted training programs and verifying the outcomes of specific ice hockey conditioning training. It could also help them to better identify and select the off-ice tests which are closest to the on-ice tests most frequently used in the literature, with the aim of providing assessments that are more tailored to athletes' needs.4.2.Despite the insights offered in this review, its limitations suggest avenues for future research. A first limitation is the identification of studies considering players' on-ice fitness-performance. Here we considered only those published in academic journals. Some interesting approaches might reside in other types of publication, such as unpublished theses, hockey federations' technical manuals or reports, and unpublished work. As an example, Hockey Canada has designed on-ice protocols and standards with a battery of tests, some based on the scientific literature and others that were empirically developed . Further5.Considering ice hockey match requirements and protocols used in the literature, the systematic review highlights the widespread use of on-ice skating tests to assess ability to repeat intense efforts, agility, acceleration and speed on the ice. Since on-ice tests relate specifically to the actions of the ice hockey player, we believe that ice hockey stakeholders can benefit from this practical and useful inventory tool through the guidance of tests adapted to the characteristics of the athlete populations they work with. Despite the issues and constraints of athletes’ testing, there is a need to assess as close as possible to real game conditions, on the ice with a full protective equipment, by using various specific skating patterns. This review proposes relevant options and solutions for researchers and practitioners  who aim to integrate on-ice testing with different populations and objectives. The increasing emphasis on age-related on-ice evaluation indicates that ice hockey is a late-developing sport, where assessment becomes more relevant at an advanced age of expertise. Most research designs do not yet consider the associations between on-ice testing and performance in real competition settings. Indeed, live-match data are also complicated to collect, whether from an ethical, methodological or technological perspective. This review also suggests a need and relevance for developing and validating tests that assess ice hockey-specific skills and decision-making abilities. Performance in ice hockey is multi-factorial and depends on physical attributes  and individual technical abilities . However, the interaction between the expression of these components and the unpredictable context of intermittent team sports remains an area that has not yet been fully assessed and decrypted. Agility is a complex but fundamental quality to evolve at the highest levels, refers to information and decision-making, playing intelligence, the core elements which each athlete must develop during their sporting career and which are challenging to evaluate from an ecological and specific perspective.