|Exam Name||:||Windows Small Business Server 2011 (R) Configuring.|
|Questions and Answers||:||55 Q & A|
|Updated On||:||February 20, 2018|
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In the Windows Small Business Server 2011 Standard Console, select the existing backup, and select Change Backup Schedule. Select Custom and select 3 AM and 6 PM.
In the Windows Server Backup console, select Backup Schedule. Add 3 AM and 6 PM as backup times.
In the Windows Server Backup console, select Backup Schedule. Select Stop Backup. Create a new backup schedule that has backups at 3 AM and 6 PM.
You are the administrator for a network that runs Windows Small Business Server (SBS) 2011 Standard as a Hyper-V virtual machine. The Hyper-V server has a catastrophic failure. You re-create the Windows Small Business Server 2011 Standard virtual machine on a new Hyper-V server by using virtual hard disk files that were restored from the backup of the failed Hyper-V server. You need to ensure that the Windows SBS 2011 Standard server returns to normal operation. What should you do?
Configure the network adapter on the Windows SBS 2011 Standard server to use a static IP address, and run the Fix My Network Wizard.
Configure the network adapter on the Windows SBS 2011 Standard server to use a static IP address, and run the Connect to the Internet Wizard.
Configure the network adapter on the Windows SBS 2011 Standard server to use DHCP, and run the Connect to the Internet Wizard.
Configure the network adapter on the Windows SBS 2011 Standard server to use a different static IP address from the previous virtual machine, and run the Set up your Internet Address Wizard.
You are migrating from Windows Small Business Server (SBS) 2008 to Windows Small Business Server (SBS) 2011 Standard. The Windows SBS 2008 server uses a trusted third- party certificate. You need to move the trusted third-party certificate from the source server to the destination server. What should you do?
Copy the certificate bundle from \\oldserver\Public\Public Downloads to the destination server and install it.
Run the Certificate Export Wizard on the source server to export the certificate to a .pfx file. Copy the file to the destination server and run the Certificate Import Wizard.
Run the Certificate Export Wizard on the source server to export the certificate to a .cer file. Copy the file to the destination server and run the Certificate Import Wizard.
From the destination server, connect to the source server's Remote Web Workplace fqdn.oldserver/remote. Install the certificate through your browser to the destination server.
You are the administrator for a network that runs Windows Small Business Server (SBS) 2011 Standard. Your company implements a cloud-based online backup that transfers your local backups to an off-site location overnight. You need to ensure that downloads by update services do not occur during the online backup transfer. What should you do?
In the Windows Small Business Server 2011 Standard Console, modify the Software Updates Settings schedule.
In the Windows Small Business Server 2011 Standard Console, modify the Server Updates to set Server Updates to None: Do Not automatically approve any updates.
Use the Update Settings console to run the Personalization Wizard.
Use the Update Settings console to modify the Synchronization Schedule to a time after your backup upload has finished.
You are the administrator for a network that runs Windows Small Business Server (SBS) 2011 Standard. Each morning User1 logs on to the Windows SBS 2011 Standard server to review the status of the previous night's backup. A new company policy states that only Network Administrators are permitted to log on to the Windows SBS 2011 Standard server. You implement the new policy. User1 is no longer permitted to log on to the server. You need to ensure that User1 can review the Windows Small Business Server 2011 Standard backup status. You also need to ensure that you comply with the new company policy without making User1 a Network Administrator. What should you do?
In the Windows Small Business Server 2011 Standard Console, use the Configure server backup task to reconfigure the backup.
In the Windows Small Business Server 2011 Standard Console, add a new report. Select Backup and schedule the report to be emailed to the user daily.
In the Windows Small Business Server 2011 Standard Console (Advanced Mode), change the user's role to Standard User with administration links.
In the Windows Small Business Server 2011 Standard Console (Advanced Mode), select Active Directory Users and Computers. Add the user to the Backup Operators security group.
You are the administrator for a network that runs Windows Small Business Server (SBS) 2011 Standard. The Windows SBS 2011 Standard server uses separate volumes for system and user data. You need to ensure that Windows Small Business Server 2011 Standard performs a full backup of all volumes every day at 1:00 A.M. What should you do?
In the Windows Small Business Server 2011 Standard Console, run the Configure Server Backup Wizard and select a Custom backup schedule.
In the Windows Small Business Server 2011 Standard Console, run the Configure Server Backup Wizard and select a Once a day backup schedule.
Open an elevated command prompt and run the wbadmin enable backup - schedule:01:00 -allCritical -quiet command.
Open an elevated command prompt and run the wbadmin enable backup - schedule:01:00 -systemState -quiet command.
You are the administrator for a network that runs Windows Small Business Server (SBS) 2011 Standard. Updates for all computers on the network are currently managed by the Windows SBS 2011 Standard server. The vendor of a line-of-business (LOB) application notifies you that a recently released Windows update is not supported by their LOB application. You need to prevent this update from installing. You must achieve this goal while allowing other updates to continue installing. What should you do?
In the Windows Small Business Server 2011 Standard Console, decline the update.
In the Windows Small Business Server 2011 Standard Console, use the Change the software update settings task to exclude the computers.
In the Services Console, stop and disable the Windows Update service on each of the computers.
In the Update Services console, create a new computer group named LOB and move the computers into this group.
You are the administrator for a network that runs Windows Small Business Server (SBS) 2011 Standard. Users report that a line-of-business (LOB) application is often unavailable. You determine that the LOB application is generating a critical event in the Application log file. The Server Event Logs section of the daily Summary Network Report includes a report of this event. You need to be notified immediately only when this event occurs. What should you do?
In the Windows Small Business Server 2011 Standard Console, create a new custom report. Select the Server Event Logs item and have the report emailed to you.
In the Windows Small Business Server 2011 Standard Console, edit the Detailed Network Report properties. Change the Schedule for generating the report and have it emailed to you.
In the Event Viewer for the Application log, use the Attach a Task to This Log action to have events emailed to you when they occur.
In the Event Viewer for the Application log, use the Attach Task To This Event action to have the event emailed to you when it occurs.
Heads up that the beta exam for SBS 2011 Standard is now available for registration NZers can register with Prometric:
December 20, 20100Article by ArticleForge
Correspondence to: T. M. Cook
You can respond to this article at
The Fourth National Audit Project (NAP4) recommended airway training for trainee and trained anaesthetists. As the skills required for management of airway emergencies differ from routine skills and these events are rare, practical training is likely to require training workshops. In 2013, we surveyed all UK National Health Service hospitals to examine the current practices regarding airway training workshops. We received responses from 206 hospitals (62%) covering all regions. Regarding airway workshops, 16% provide none and 51% only for trainees. Of those providing workshops, more than half are run less than annually. Workshop content varies widely, with several Difficult Airway Society (DAS) guideline techniques not taught or only infrequently. Reported barriers to training include lack of time and departmental or individual interest. Workshop-based airway training is variable in provision, frequency and content, and is often not prioritised by departments or individual trainers. It could be useful if guidance on workshop organisation, frequency and content was considered nationally.
Competence in a range of airway management skills is important for all anaesthetists. Although airway emergencies are uncommon, the chance of subsequent death or permanent brain injury when they occur is significant . Concerns have been raised over the past 15 years regarding the quality and availability of airway training in the United Kingdom [2-5]. In the Fourth National Audit Project (NAP4) of the Royal College of Anesthetists (RCoA) and Difficult Airway Society (DAS) , the commonest contributory factors reported were judgement and trainingeducation. In NAP4, 84% of cases were judged to include poor or mixed (good and poor) quality care, and for cases leading to death or brain damage this increased to 93%. Airway deaths described in NAP4 and recently elsewhere illustrated technical failings as well as non-technical contributory factors [1, 6-8]. With the infrequency of major airway problems, and the necessity to train and maintain technical and non-technical skills, airway training workshops are widely used by the Association of Anaesthetists of Great Britain and Ireland (AAGBI), RCoA, DAS and many other organisations. It is impractical for these national organisations to train all anaesthetists, so the question arises as to whether all anaesthetists have access to similar workshop-based training locally.
NAP4 recommended that each UK anaesthetic department should have a nominated airway lead (AWL) , and this was endorsed by the RCoA and DAS . The main roles of the AWL include: overseeing local airway training for anaesthetists and assisting in airway training more widely; and ensuring local policies exist and are disseminated for predictable airway emergencies.
The recommendations of the NAP4 report specifically included: proficiency in simple emergency airway care; that all anaesthetists should learn ‘low skill rescue intubation’ through a supraglottic airway device (SAD), such as those including an Aintree Intubation Catheter; and manikin-based practice in the performance of cricothyroidotomy . The report emphasised training and rehearsal of airway management techniques (for anaesthetists and intensivists), specifically encouraged multidisciplinary training of both technical and non-technical skills and advised that techniques and guidelines should be taught and rehearsed using locally available airway equipment and algorithms. The report recommended that a record of staff training was maintained. It is difficult to conceive that these techniques and skills might be taught or learnt without practical instruction; i.e., workshop teaching.
The recently published 2015 DAS guidelines were heavily influenced by the findings of NAP4 and specifically advocate training in use of videolaryngoscopy, insertion of second generation SADs and performance of a ‘scalpel cricothyroidotomy’ front of neck airway . Regular training for all anaesthetists is emphasised to ensure retention of technical and psychomotor skills.
‘Technical training’ has a role in establishing psychomotor skills and knowledge of algorithms for trainees, updating those skills for more senior staff and training all staff in emerging or newly adopted techniques and algorithms. Retention of psychomotor skills has been shown to be better with frequent ‘hands on’ practical training and practical skill ‘decay’ is now well recognised .
We surveyed all UK anaesthetic departments to explore current practices and examine local provision of out-of-theatre airway training, content of airway workshops and barriers to their provision.
A survey was designed by the authors (TC and FK) and was discussed with our local Research and Development Department, who confirmed it did not meet current NHS definitions of research and that formal approval by the Regional Ethics Committee was not required.
The survey was part of a larger survey of practice and included 12 questions relating to airway training (Appendix 1), investigating whether the department had an AWL, whether out-of-theatre airway training was provided locally and, if so, its frequency, target audience, content and whether it was voluntary or mandatory. If no out-of-theatre training was provided, we explored the major barriers preventing it.
The survey was conducted in conjunction with the Health Service Research Centre (HSRC) of the National Institute of Academic Anaesthesia at the RCoA, whose own database of was used to identify all UK NHS anaesthetic departments and departmental AWLs. The survey was reviewed by the HSRC executive board before being distributed but was not formally piloted. The survey was sent to Departmental AWLs where these were known, and to anaesthetic departments where they were not, requesting completion of an on-line survey. Some AWLs had responsibility for more than hospital (e.g. a Trust or Board – the terms for a group of hospitals in EnglandWalesNorthern Ireland, and Scotland, respectively) and they were asked to indicate, in their response, whether they had responded on behalf of an individual department or several departments together. To improve response rates, if no response was received, an email was sent to the anaesthetic departmental Quality Audit and Research Coordinator (QuARC), and if still no response was received, an email was then sent to the Clinical Director. In this manner, serial attempts were made to elicit a response but only one response was received from each hospital or group of hospitals. The survey was conducted during 2013 and closed in January 2014. Responses were collected independently by the HSRC staff, manually checked to ensure that only one response per anaesthetic department was counted, and responses were then de-identified.
Data were entered into a Microsoft Excel 2010 (Microsoft Cooperation, Redmond, WA, USA) spreadsheet.
Surveys were distributed to 335 hospitals. A total of 171 replies were received. These replies were from respondents representing 99 TrustsBoards and 72 individual hospitals, in total accounting for 206 hospitals (62% response rate).
Respondents were principally consultants (167171, 98%), the others being associate specialists (3171, 1.5%) and one senior specialist registrar (1171, 0.5%). Distribution of hospitals was as follows: teaching hospital 49171 (29%), district general hospital with teaching hospital affiliation 82171 (50%), district general hospital 28171 (16%), paediatric hospital 5171 (3%) and other specialist hospital 6171 (4%). Responses were received from hospitals in all training regions of the UK.
Ninety-one percent of responding departments (155171) had an AWL.
Eighty-four percent of respondents (142169) reported provision of workshop-type manikin-based airway training. In 86169 (51%) of anaesthetic departments, this training was provided for anaesthesia staff of all seniorities, and in 65169 (38%), training was only for trainees. Therefore, 27169 (16%) of departments provided no training of this type at all, and 83169 (49%) of responding departments provided no training for non-trainees (Table 1). Frequency of workshop-type airway training varied considerably (Table 1). At least twice-yearly training was provided in 71169 (42%) of respondents’ departments – 24% for trainees only and 18% all seniorities.
Table 1. Anaesthetic departmental provision of out-of-theatre airway training workshops. Respondents to this question = 169. Values are number (proportion) Any frequencies 86 (51%) 65 (38%) Once a year 56 (33%) 24 (14%) Twice a year 23 (13%) 26 (15%) Three times a year 3 (2%) 4 (2%) Four times a year 4 (2%) 11 (6%)
Table 2 shows the distribution of type of workshop training provided by departments. A little over half of respondents’ hospitals (92169, 54%) provided formal airway training workshops and in less than one third (54169, 32%) attendance was mandatory and registered. Provision of formal training, more than once a year, whether mandatory or voluntary, was reported in 52169 (31%) of departments.
Table 2. Type of workshops arranged and frequency. Respondents to this question = 169. Values are number (proportion) Formal mandatory workshop training as part of induction 14 7 3 24 (14%) Formal mandatory workshop with register of attendance 9 15 1 25 (15%) Formal mandatory workshop without register 3 2 0 5 (3%) Formal workshop with voluntary attendance 14 11 13 38 (22%) Informal workshopmanikin training 18 15 17 50 (29%) No formal arrangement 17 2 0 19 (11%) No such training 8 0 0 8 (4%)
The content of practical airway training varied considerably (Fig. 1).
Components of airway training and frequency of inclusion in all workshopstraining. The skills are ranked by the frequency with which they are included. DAS, difficult airway society, SAD, supraglottic airway devices, RSI, rapid sequence induction. Blue, always included; red, sometimes included; green, never included. Values on the y-axis are number of respondents and the x-axis presents percentage of respondents for each question.
Seventy-eight respondents reported 114 reasons why they did not provide practical airway training (Fig. 2). Lack of availability of trainers was the commonest cause (39% of responses), followed by lack of equipment (26%) and lack of interestprioritisation by trainers (24%). Lack of interest by trainees was reported by one respondent (0.9% of responses).
Reasons why airway training is not provided. Seventy-eight respondents reported 114 reasons. Results presented as proportion of responses.
Anaesthetists require airway skills – both basic and advanced – for routine airway management and to enable safe management of airway difficulties and crises. These skills and techniques need to be learnt and updated by both trainees and trained anaesthetists. There is at present no agreed source to define what those skills and techniques might be or how training should be undertaken. The RCoA curriculum for training [14-16], the recommendations arising from NAP4 [1, 11] and skills required to achieve the procedures included in the DAS guidelines  are all potentially relevant. Although airway workshops appear to be widely used at a national, regional and local level, we are not aware of any specific guidance on the nature, frequency or content of this type of training or whether it should be mandatory or voluntary. Without a national policy on this, current practices will remain ad hoc and in some settings, training will be absent or inadequate. This survey has demonstrated exactly this.
While neither NAP4 nor the 2015 DAS guidelines specifically recommend local workshop-style training, this has emerged as one method to deliver training and is used by several national organisations. These national organisations cannot train all anaesthetists, even intermittently, and if out-of-theatre airway workshops have value, it is logical that they should be provided at a local level. Training anaesthetists at locally provided airway workshops enables training with anaesthetic colleagues from their own department, with locally available anaesthetic equipment and with their own anaesthetic nurses and operating department practitioners (ODPs). The DAS 2015 guidelines emphasise the importance of training with locally available equipment, and state that ‘local training will be necessary’ . Marshall and Pandit, commenting on the DAS 2015 guidelines recently, wrote that “it would seem important that a specific ongoing competency requirement for all anaesthetists should be ‘airway management’, to include all aspects of these new guidelines” . The Australian and New Zealand College of Anaesthetists (ANZCA) already mandate training in emergency airway management for both trainees and trained anaesthetists .
Airway workshops enable training of new skills on manikins, familiarisation with new equipment and techniques and learning the use of emergency algorithms. Many of these techniques are impractical to teach or learn or practice in patients, yet are part of national and international guidelines and expected emergency airway management . For junior anaesthetists, airway workshops allow acquisition of skills and knowledge; for senior anaesthetists, they enable refreshing and updating of skills and knowledge previously learnt, and acquisition of newly developed or newly recommended skills. Regarding UK training: while many of the component techniques recommended by NAP4 and described in the DAS guidelines (2004  or 2015 ) are included in the training curriculum of the RCoA, it is notable that they are described in general terms and that specific techniques and the DAS guidelines themselves are not mentioned [13-15]. Therefore, completion of this specialist training may not equate with acquisition of the skills and knowledge recommended by NAP4 and included in the DAS guidelines.
Although this paper focuses on UK experience, there is evidence that similar training and practical knowledge gaps exist elsewhere [20-22].
Our survey, completed in 2014, shows that local out-of-theatre airway training in the UK remains highly variable in its provision, target audience, frequency, content and whether it is mandatory or voluntary. In half of UK hospitals, it is non-existent for senior staff and in 16% for all anaesthetists. In practice, airway workshops can be readily organised with minimal equipment, using departmental resources. Airway workshops can be used to teach both technical and non-technical skills and have a role in teaching team-working if expanded to incorporate multidisciplinary groups, as recommended in NAP4 .
The content of practical airway training also varied considerably. As might be expected, much of the content related to the DAS 2004 guidelines . The commonest components were ‘DAS airway guidelines’ (always included by 77% of respondents and alwayssometimes included by 97%) and ‘management of can't intubate can't ventilate (CICV)’ (74% always, 95% alwayssometimes). Several components of the DAS 2004 guidance, which are now more strongly emphasised in the 2015 guidance, were infrequently taught: these included surgical (scalpel) airway (always taught 36%, never taught 17%); fibreoptic-guided intubation via a SAD (always 37%, never 19%); and waking the patient during difficulty (always 42%, never 20%). Also, management of difficult intubation during rapid sequence induction was ‘always’ included in workshop training in fewer than half of departments. Conversely, several components not included in the DAS 2004 guidelines were frequently taught. These included videolaryngoscopy (alwayssometimes 92%) and intubation via a SAD with an Aintree Intubation Catheter (alwayssometimes 86%). For intubation via a SAD, the ‘fibreoptic and Aintree-guided’ technique was the commonest (always taught 46%), followed by ‘fibreoptic and tracheal tube’ (37%) and ‘blind intubation (28%). These are all consistent with changes in the DAS 2015 guidelines  and might suggest a degree of anticipatory preparedness for the updated guidelines, even before their publication. However, among the techniques for emergency front of neck airway, narrow-bore cricothyroidotomy was the most frequently taught (always 63%), followed by wide-bore cannula over needle (53%), wide-bore Seldinger (48%) and surgical airway (36%). As the last technique is the primary technique described in the DAS 2015 guidelines, it will need a re-alignment between what is recommended and what is taught. The low rate of teaching of surgical airways is also at odds with recommendations of NAP4 . With the variation in content seen in the workshops, it appears some currently being run are not fit for purpose. If a national policy was developed to guide such workshops and courses, it would probably improve not only the provision of courses but the consistency of content.
The major reason cited for not running airway training workshops was the lack of time or lack of interest or prioritisation from trainers – these combined to account for more than half the cited reasons. This raises concerns about priorities in some anaesthetic departments, and may hint that pressures to maintain ‘service’ are impacting on the ability and enthusiasm to train and maintain skills. Lack of facilities or equipment to perform airway workshops accounted for much of the remaining barriers to workshop provision. In contrast, ‘lack of interest’ by trainees was not prevalent.
In addition to variation in provision, frequency and content, we also identified variation in whether workshop training was mandatory or voluntary. Only one in six of those providing workshops provided mandated airway workshops at least annually for all department members. This lack of regular, mandated, structured training in the emergency airway skills that anaesthetists require contrasts markedly with other mandated training. Even excluding other forms of hospital mandatory training, a variety of advanced life support courses are now expected for both trainees and seniors. These generic courses do not include airway management training of a level appropriate to expert anaesthetists.
There are limitations to our study. The response rate, despite repeated efforts to improve this, was 62%. However, we received responses from all four countries in the UK, from all training regions and the distribution of the type of hospital that responded is broadly similar to the national distribution . It is possible that those departments with an airway lead and airway workshop training were more likely to respond, leading to responder bias. Also of note is that this survey involved self-reporting, with no external validation of findings. We were not able to explore whether the size of a hospital impacted on the provision of training as the survey did not identify hospital size or activity. We also did not capture whether regional-based training (likely only for trainees) acts as an effective alternative to local training. The survey focused on technical skills and it is acknowledged that non-technical skills and training also has great importance in maintaining overall ‘airway competence’.
In conclusion, this survey provides a snapshot of airway workshop provision in the UK. It shows a variation in the provision, target audience, content, frequency and mandatory nature of out-of-theatre airway training for anaesthetists. The majority of trained UK anaesthetists do not have access to local airway workshop training. The predominant barrier to airway training workshops was trainer time and enthusiasm. Fatalities relating to difficult airway management continue to occur in UK hospitals [24, 25] and the focus of coronial enquiry is now including the quality of training of junior and senior anaesthetists. The results of this survey provide an insight into the provision and lack of provision of regular airway training for UK anaesthetists. These data may be valuable for national bodies, who may wish to consider whether the current state is desirable or acceptable and whether national guidance on provision and content of locally delivered airway workshop training might be developed.
We thank Mrs Madeleine Bell and Mrs Mary Casserley at the RCoA for administering the survey and all respondents for their contributions. We thank Dr Jonathan Benn (Lecturer in Quality Improvement in Healthcare, Imperial College London) for advice on hospital types as described in the National Reporting and Learning System clusters.
TC is a member of the Executive Board of the Health Service Research Centre HSRC of the National Institute of Academic Anaesthesia. He is the Airway Advisor to the Royal College of Anaesthetists. This study was supported by the Health Service Research Centre of the National Institute of Academic Anaesthesia and by the Department of Anaesthesia, Royal United Hospital, Bath. No other funding or competing interests declared.
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2016 The Association of Anaesthetists of Great Britain and Ireland
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The OML-SprayDrift model (Operationelle Meteorologiske Luftkvalitetsmodeller, meaning Operational Meteorological Air Quality Model) is a combination of two Gaussian model principles. The Gaussian tilting plume method11,12) determines the amount of spray deposited inside the directly sprayed zone. The remainder spray is treated as area sources located in the track and is dispersed applying a traditionally reflected Gaussian plume and the deposition beyond the track is calculated by deposition velocity. The model calculates the water and possible pesticide evaporation from the droplets and the resulting change in diameter and vertical velocity as a function of travel distance. Deposition outside the track is converted to negative surface sources following the principle of surface depletion described by Horst.15) The negative surface sources ensure that the calculated vertical profiles of the horizontal drift at some distance from the edge of the field have a maximum above the ground, which also has been observed and modeled.9) The model operates on droplet classes in size intervals of 10 µm.
The dispersion model is based on the Danish Gaussian plume model OML, which calculates the atmospheric dispersion of pollutants from multiple point and area sources and has been validated against many different datasets including non-buoyant surface releases.16) The model is a regulatory model used by the Danish authorities, consultants, and industry. In OML, turbulence is described as continuous functions of micrometeorological parameters like friction velocity, heat flux from the surface, aerodynamic roughness, and the Monin–Obukhov length describing the atmospheric stability. The vertical and horizontal dispersion from a point source is described as a Gaussian (normal) distribution. For a point source placed at coordinates (0, 0, H) (m), the concentration c (g m−3) at the point (x, y, z) is calculated disregarding deposition as follows:
where Q is the emission rate (g sec−1), u is the wind speed (m sec−1), H is the height of the source (m), and σy and σz are the horizontal and vertical dispersion parameters (m), respectively. The reflection terms refer to the reflection from the ground surface of the plume and are active outside the track in the OML-SprayDrift model. In most cases, spray drift is a two-dimensional phenomenon, because the long spray track will smooth out the horizontal dispersion when estimating the average concentration. Therefore, the OML-SprayDrift model disregards the horizontal influence and is a 2D model.
1.2. Deposition inside the track
Inside the spray track, deposition is calculated using a Gaussian tilting plume or settling plume principle.11,12) The height of the droplet plume centerline, H, in the concentration equation is decreased due to the descending droplets. The principle is applied to a number of droplet size classes. In this study, the classes consist of 10 µm droplet diameter intervals and are in the calculations represented by the median diameter of the interval center. In this case, the theoretical dispersion is not affected by the presence of the ground surface, and the plume is allowed to disperse under the surface; i.e., the reflection term in the concentration equation is neglected. At a given distance, the total deposition is equal to the part of the plume that is located beneath the surface.
The average deposition inside a track is represented by the droplets released at the center of the boom. At the edge of the boom, the deposition for each droplet class is calculated with the tilting plume where the vertical position of the droplet is calculated by the droplet model described in Section 1.4, taking into account the droplet exit speed from the nozzle, the evaporation, and the change in droplet size and speed.
1.3. Deposition beyond the track
After droplet release, the speed of the smaller droplets reaches a terminal speed within a few tenths of a second, which is not affected by the nozzle exit speed, but for boom heights of 0.5 m, the larger droplets will deposit inside the track. The smaller droplets, which will mainly deposit outside the track, have a terminal speed that is comparable to or less than the typical speed of turbulence eddies, i.e., in order of the friction velocity, u*. This means that the rate of deposition due to turbulent transport will be comparable to the rate of deposition due to pure sedimentation.
The OML-SprayDrift takes this turbulent deposition into account using the surface depletion principle.15) Deposition at a given distance downwind from a source is handled as a negative source with the same strength as the deposition rate.
The deposition rate Dep is calculated based on the principle of deposition velocity vd. The deposition is proportional to the deposition velocity vd(z) and the concentration c(z):
where z is the reference height, which is set to 0.5 m in the spray-drift model. The deposition velocity is parameterized analogous to electrical resistances and the dry deposition velocity of particles or droplets14):
where vs is the settling velocity of the drop as a function of its diameter, ra (sec m−1) is the aerodynamic resistance, and rb is the laminar sublayer resistance close to the surface. The aerodynamic resistance in the mixing layer is defined as
where κ is the dimensionless von Karman’s constant, u* (msec) is the friction velocity, z0 (m) is the roughness length, and ψ is Businger’s corrections function for atmospheric stability.17)
For particles, the laminar sublayer resistance close to the surface is given as
where Sc is the dimensionless Schmidt number: νD, where D is the diffusivity, ν is the kinematic viscosity, and St is the dimensionless Stoke number: (u2*vs)(g ν), where g is gravity (m sec−2). The settling velocity of the droplets is incorporated in the Stoke number.
1.4. Evaporation and fall velocity of droplets
The dispersion and deposition model is coupled with a droplet model describing droplet evaporation and the resulting changes in size and velocity. The model takes into account the droplet ejection velocity as well as the relative humidity and ambient temperature. The model is based on a model for pure water and further developed to deal with the pesticide content of the droplet and its possible evaporation. The model assumes no interaction between droplets and that the droplets have no influence on the air. The model does not take formulations and adjuvants into consideration, although it is known that formulations and adjuvants can influence the droplet size distribution18–20) and thereby affect the drift potential. Although the results of Sanderson et al.21) were related to specific experimental and meteorological conditions, they concluded that drift is considerably lower using water-dispersible granules or liquid-flowable formulations of Propanil compared to emulsifiable concentrates. Chapple et al.22) tested different adjuvants and found that six out of seven adjuvants shifted the droplet spectra relative to water, either to smaller or larger diameters.
The model describes droplet behavior after ejection. A droplet is affected by gravity, the drag force of the air, and the evaporation of water and pesticide. Fall velocity and evaporation are described by solving mass, moment and energy equations for a single droplet. These equations are transformed to equations for diameter, fall velocity, and temperature, respectively. Together with the ambient temperature and relative humidity, these equations determine the exchange and thereby the changes in size, velocity, and temperature of the droplet. A detailed description of the droplet model is found in Supplemental Material.
Droplet fall velocity is an important parameter for the deposition rate to the ground surface and primarily depends on the diameter. Even though the droplet exit speed at the nozzle outlet is in the range of about 15–25 msec,23) the smallest droplet reaches a much lower terminal velocity within a few tenths of a second after exit. However, a continued change in diameter and velocity occurs due to evaporation. For the smallest droplets, the change can be fast, as shown in Fig. 1. For a given diameter, the relative humidity of the air is the most important parameter for the evaporation rate, as shown in the figure.
When the droplets contain a pesticide with a low vapor pressure, the evaporation and change in diameter of the droplets almost stop, and they reach a minimum diameter. This occurs when the relative water content equals the relative humidity of the air. If the pesticide also evaporates, the minimum diameter decreases accordingly.
1.5. Calibration and validation
The model was calibrated and validated against the field measurements described in the next section. The field data were divided into data from the years 2005 and 2010, where a standard flat-fan and an air-injection nozzle were used, respectively. Calibration was performed using the 2005 data and validation was done on the 2010 data. Many spray-drift models have been calibrated, e.g., using field canopy porosity and velocity scaling parameters,9) fitting horizontal and vertical eddy diffusivities Ky and Kz to the first trail in a series,12) or adding empirical corrections to the evaporation rate that changed the deposition downwind with a factor of 2.6) Teske et al.7) describe the great variance between different empirical parameterizations of the nozzle-induced airstream velocity due to the entrainment of air. In this study, the calibration also involves the effects of the nozzle-induced airstream.
Calibration was based on the deposition inside the spray track. The droplet model only handles single droplets and does not take into account the effect of the whole continuous spray cloud on the airstream close to the nozzle. A droplet transfers momentum to the surrounding air and is slowed down. The droplet reaches the terminal speed at a certain fall distance, but all the droplets in the spray cloud together create a downward airstream that increases the fall distance compared to the calculated fall distance for a single droplet. Therefore, an algorithm for the empirical additional fall distance is established based on the 2005 data. It is anticipated that a high wind speed destroys the induced airstream. The additional fall distance, Δz (m), is a function of the wind speed at boom height uB (m sec−1):
The algorithm is applied for uB below 4.4 m sec−1, and Δz is 0 m for larger uB, where uB is calculated from the meteorological observations taking into account the atmospheric stability using Businger’s corrections16) to the neutral logarithmic wind profile.
1.6. Model input and output
As input, the model needs meteorological information on wind direction, friction velocity (turbulence), Monin–Obukhov length (atmospheric stability), aerodynamic roughness, temperature, humidity, mixing height and boom height. The nozzle droplet spectra and ejection velocity are also needed together with pesticide tank concentration and application rate (L ha−1). Driving speed is assumed to be around 7 km hr−1.
The model calculates the ground-surface deposition and the vertical profile of the horizontal pesticide flux, in principle, at any distance downwind of any field size. Also, the droplet spectra can be calculated at any position.
Most spray models are developed using deposition measurements. This type of measurement can be difficult to perform properly in order to measure the far-field drift deposition of small droplets using smooth horizontal surfaces, such as alpha-cellulose sheets, on a rough field surface.8,11) To avoid this problem, this study measured the vertical profile of the horizontal drift. In the far field, the total amount of collected spray drift will be much larger than the horizontally deposited spray drift measured per unit area, which reduces uncertainty in measurements.
2.1. Field measurements
A series of spray experiments were carried out in order to determine pesticide droplet dispersion from spray tracks. These experiments were conducted so that horizontal flux at different heights and different distances from the spray boom was determined24,25) using sodium fluorescein as a tracer. The tracer is assumed not to evaporate and has a molar mass of 376.3 g mol−1, which is about the value of many pesticides.
Spraying was performed with a conventional tractor-mounted sprayer. Spray nozzles were either Hardi 4110-16 (flat fan; Hardi, Denmark) or TeeJet AI 110-04 (air induction; TeeJet, USA). The spray boom was 12 m wide with 24 nozzles, and boom height was adjusted to 50 cm above the vegetation. The tractor driving speed was about 7 km hr−1. The conditions for each spraying are presented in Table 1. Before calibration and validation, all measurements were normalized to the same application rate, i.e., 300 L ha−1 and 1.49 g L−1.
Table 1. Meteorological conditions and settings for the spray equipment during spray events Parameter, unit Trial April 05 May 05 June 05 Aug. 05 Sept. 05 June 10 June 10 Environmental conditions Wind speed, m sec−1 5.5–6.2 2.0–3.6 2.9–3.8 3.7–4.5 2.4–3.3 4.6–5.8 4.8–5.6 u*, m s−1 a) 0.51–0.61 0.19–0.28 0.39–0.45 0.34–0.53 0.29–0.58 0.45–0.62 0.51–0.61 L, mb) −57–−88 −5–−21 −58–−88 −21–−87 −24–−107 244 −116–−196 Heat flux, W m−2 206–255 51–130 74–120 93–205 91–164 44–112 85–144 Temperature, °C 10–11 11–12 17–18 17–18 22–24 12–15 15–16 RH, % 42–50 53–59 65–79 47–60 45–65 67–77 63–65 Spraying equipment settings Nozzle typec) FF FF FF FF FF AI AI Pressure, MPa 0.55 0.55 0.30 0.30 0.30 0.30 0.30 Flow rate, L min−1 1.6 1.6 1.1 1.1 1.1 1.6 1.6 VDMd), µm 198 198 213 213 213 439 439 Drop ejection speede), m sec−1 18.0 18.0 15.5 15.5 15.5 9.2 9.2 Tractor speed, km hr−1 7 7 7 7 7 6.4 6.4 Application rate, L ha−1 300 300 200 200 200 300 300 Tank concentration, g L−1 1.49 2.23 1.63 1.99 1.83 2.23 1.93
a) The parameter u* is the friction velocity, a measure of air turbulence. b) L (Monin–Obukhov number) is a parameter of atmospheric stability. c) FF=Hardi flat fan 4110-16 nozzles and AI=TeeJet Air Injection −110-04. d) Volume median diameter from measurement in laboratory. e) Value from centre of measured volumetric droplet velocity distribution from continuous scan in laboratory.
The experiments took place along a hawthorn hedgerow on seven occasions (April 2005, May 2005, June 2005, August 2005, September 2005, and twice in June 2010). The meteorological conditions for wind speed, wind direction, turbulence, temperature, and heat flux were measured with an ultrasonic anemometer at 4 m height on a mast in the center of the 200 m×200 m field, i.e., 100 m from the hedgerow. Relative humidity was also measured (Table 1). The calculated meteorological data during the individual trails are based on 10-min averages in correspondence with Bird et al.8)
Measurements were performed for five spray tracks parallel to the hedgerow with an increasing distance from the hedgerow (cf. Fig. 2). The hedgerow consisted almost entirely of hawthorn (Cartages laevigata (Poiret)) trees about 4–5 m high and 1–2 m wide, with a few gaps. Hawthorn is deciduous, and in Denmark leafing occurs in early May, flowering in MayJune. Measurements of the vertical wind profile at 4 positions (1.0, 2.0, 3.5, and 5.1 m above the ground) in the hedgerow were compared with the wind measurements about 100 m upstream at the open field. These measurements indicated that the total horizontal flux from ground to 5.1 m was reduced by about 10% (data not shown). This indicates a small vertical component in the mean flow and is consistent with a measured average vertical wind component at 5.1 m of 8–9% of the horizontal component. Compared to other uncertainties, this is only a minor violation of the implicit assumption of horizontal mean flow.
Spray drift was collected using commercial plastic hair curlers (M-cosmetics, Denmark) mounted on masts 0.5, 1, 2, and 4 m above the ground. The curlers were covered with 3-mm-long “hair,” 0.15 mm in diameter, and were assumed to collect droplets with a diameter down to 10 µm and an effective crosswind area of 2 cm×6 cm. These assumptions were associated with some uncertainty due to the complex structure of the curler.
The masts were placed at five different distances to a hedgerow almost perpendicular to the wind direction. The mast spacing was 12 m, corresponding to the width of the spray boom. At each distance, five masts were set up at 10 m intervals, and the first row was placed just in front of the hedgerow, resulting in a total of 25 masts. In each mast, two hair curlers were placed upright at each of the four four sampling heights, giving 10 curler measurements at each height at each distance that were averaged and used in the model calibration and validation. Before spraying the next track, a new row of masts mounted with curlers was erected. In order to reduce the large variability in the measurements, some extra trails were performed where the tractor drove back and forth 10 times in the third track 24 m away from the hedgerow, and measurements were only made in the hedgerow.
2.2. Droplet size distributions
Three different droplet size distributions were applied during the field experiments, i.e., the standard flat-fan Hardi 4110-16 at 0.30 and 0.55 MPa and the TeeJet air-induction nozzle 110-04 at 0.30 MPa. The nozzle droplet spectra were experimentally determined using the PD laser-based measurement setup and protocol.26,27) Cumulative droplet size distributions are shown in Fig. 3 together with the results of the flat-fan nozzle XR 110-02 at 0.30 MPa28) used for the sensitivity analysis in a later section.
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Azorhizobium caulinodans ORS 571 (DSM 5975, ), Bacillus subtilis subsp. subtilis 168 (ATCC 23857, ), Cupriavidus metallidurans CH34 (DSM 2839, ) and Pseudomonas protegens Pf-5 (ATCC BAA477, ) were grown in 20 ml of Luria-Bertani broth (LB; Oxoid) at 25 °C overnight, with orbital shaking at 250 rpm. To prepare the inoculum suspension of each bacterial strain, 15 ml of the culture grown overnight were centrifuged at 5000 × g for 10 min at room temperature. The supernatant was discarded and the bacterial cells were washed three times by suspending in 20 ml of sterile isotonic solution (0.9 % NaCl) and centrifuging at 5000 × g for 10 min. The concentration of each bacterial suspension was assessed by measuring the optical density (OD) at 600 nm with a spectrophotometer (Ultrospec 3100, GE Healthcare Life Sciences) and adjusted to 5 × 108 cells ml−1.
Debaryomyces hansenii 767 , Pichia stipitis 6054 , Schizosaccharomyces pombe 972 h (DSM 70576, ), Saccharomyces cerevisiae S288c (ATCC 204508, ) and T. atroviride SC1 (available in our strain collection and in the commercial product Vintec, Bi-, Londerzeel, Belgium) were grown on malt extract agar (MEA; Oxoid) at 25 °C. Aspergillus niger 513.88 , Fusarium oxysporum f. sp. lycopersici 4287 ( 123668, ) and Penicillium chrysogenum Wisconsin 54–1255 (DSM 1075, ), were grown on potato dextrose agar (PDA; Oxoid) at 25 °C. To prepare the inoculum suspension of filamentous fungi and yeasts, conidia and cells were collected from 21-day-old cultures by washing each plate with 3 ml of sterile isotonic solution, using a glass rod under sterile conditions. The suspension of each strain was filtered with sterile cloth, and cells were washed three times by suspending in 6 ml of sterile isotonic solution and centrifuging at 5000 × g for 10 min. The concentration of each conidia and cell suspension was adjusted to 5 × 108 cells ml−1 by counting with a hemocytometer under a light microscope. For the inoculum suspension of A. mellea M6132 (kindly provided by Dr. Simone Prospero, Swiss Federal Research Institute, Birmensdorf), 1 g of mycelium was collected from 21-day-old culture grown on MEA at 25 °C and suspended in 4 ml of sterile isotonic solution. Sterile steel beads were added and the A. mellea mycelium was ground in a mixer-mill disruptor (MM 400, Retsch) at 25 Hz for 3 min. The ground mycelium was washed three times by suspending in 4 ml of sterile isotonic solution and centrifuging at 5000 × g for 10 min, and it was then suspended in 2 ml of sterile isotonic solution.
The viability of counted cells in each inoculum suspension was validated through a dilution plating method (Additional file 1). Basically, 0.1 ml of each inoculum suspension was subjected to 10-fold serial dilution, 0.2 ml of each dilution was plated in triplicate on plates containing the appropriate media for each strain, bacterial and fungal colony forming units (CFUs) were then assessed after incubation at 25 °C for 24 and 48 h respectively.