Separation and Disinfection of Contagious Aerosols from the Perspective of SARS-CoV-2

An assessment was performed on methods of separating and disinfecting airborne droplet nuclei containing viruses, such as SARS-CoV-2. The droplet nuclei originate from evaporating aerosols emitted by the coughing, singing, sneezing, etc. of infected humans. Based on empirical data and theoretical analysis, we successively determined: (i) the particle number distribution of nuclei versus the nucleus diameter, (ii) the statistical distribution of the viral content in the droplet nuclei starting from a uniform random distribution of viruses in the mucus, (iii) the particle number distribution of droplet nuclei containing at least one virus particle, and (iv) the effectiveness of methods for removing and disinfecting nuclei containing one or more virus particles from indoor air; viz., ventilation with fresh air, filtering with porous media, such as HEPA, and centrifugal separation and simultaneous disinfection, particularly with a rotational particle separator (RPS). Indoor aerosol removal with RPS supplemented with HEPA to arrest tiny volumes of very small particles was found to be the most effective. It is as good as particle removal through ventilation with clean air over long periods of time. An RPS facilitates direct elimination of viruses in the collected nuclei by flushing with a disinfection liquid. The components of an RPS are recyclable. Combining HEPA with an RPS extends the service time of HEPA by almost two orders of magnitude compared to the relatively short service time of stand-alone HEPA filters.

308 Effects of Roughage Source on Growth Performance, Carcass Characteristics, and Rumination Time of Beef Steers Fed Steam-flaked Corn Finishing Diets

We hypothesized that roughage source would not impact rumination time and growth performance if the different sources provided a similar concentration of dietary neutral detergent fiber (NDF) and physically effective NDF (peNDF). This experiment’s objective was to evaluate rumination time, and growth performance steers consuming finishing diets with differing roughage sources (corn stalks, cotton burrs, or wheat silage). Beef steers (n = 49; BW = 317 + 5.6 kg) were used in a completely randomized design with 3 dietary treatments. Steers consumed a steam-flaked corn-based diet containing corn stalks (CS), cotton burrs (CB), or wheat silage (WS) included at 7% (DM basis). Dietary NDF was similar (P = 0.36) across treatments. Each steer was fitted with a sensory collar to record daily rumination. Weekly ingredient and dietary samples were estimated for physically effective NDF (epeNDF) using the Penn State Particle Separator. Actual physically effective NDF (apeNDF) was calculated based upon rumination time. Neither initial nor final body weight (BW) differed between treatments (P > 0.52); nor did average daily gain (ADG), dry matter intake or carcass adjusted variables of FBW, ADG, empty BW, or empty body fat (P > 0.31). However, gain to feed (G:F) tended to differ (P = 0.06) between treatments. The CS diet had the greatest G:F with no difference (P = 0.75) between CB and WS. Dietary NDF and epeNDF were similar (P > 0.35) among roughage sources; however, CB had the least apeNDF, consistent with lower rumination time (P < 0.01). When energy values were calculated from animal performance, the CS diet had the greatest observed energy values, followed by WS and CB having the least. These results indicate roughage source impacted rumination time, although steers were fed a steam-flaked corn-based finishing diet with similar dietary roughage and NDF inclusions.

251 Effects of Roughage Source on Rumination Time and Ruminal Ph in Steers Fed a Steam-flaked Corn Finishing Diet

Research is limited on how physically effective fiber from various roughage sources aids in rumination time and ruminal pH of finishing beef cattle. This experiment’s objective was to evaluate rumination time and ruminal pH of beef steers consuming finishing diets with varying roughage sources (corn stalks, cotton burrs, or wheat silage). We hypothesized that roughage type would not impact rumination time and ruminal pH if different sources provide similar dietary neutral detergent fiber (NDF). Ruminally cannulated steers (n = 6; average BW = 644.56 + 13.15 kg) were used in a 3 × 3 replicated Latin square with 3 dietary treatments and 3, 21-d periods (20-d diet adaptation, 1-d sampling). Steers consumed a steam-flaked corn-based finishing diet containing corn stalks (CS), cotton burrs (CB), or wheat silage (WS) included at 7% (DM basis) of the diet. Dietary NDF was similar across treatments. Steers were fitted with a sensory collar to record daily rumination (Allflex Livestock Intelligence). Ruminal pH was measured using a handheld pH probe on d-21 at 0, 3, 6, 12, 24 hr postprandial. The NDF and dry matter intake (DMI) were greatest for steers consuming the WS diet (P < 0.01) while CS and CB diets did not differ (P = 0.81). While dietary NDF and estimated physically effective NDF (peNDF) were similar among roughage sources, CB had the lowest actual peNDF, consistent with lower rumination time (P < 0.01) and lower ruminal pH (P = 0.29). This experiment’s results indicate that roughage source impacted rumination time despite feeding steers a steam-flaked corn-based finishing diet with similar roughage and NDF levels. Using rumination time (min/d) to determine peNDF was a better indicator of rumen function parameters than particle size measured via the Penn State Particle Separator equation.

233 Effects of Harvest Maturity And/or Kernel Processing on Corn Silage Processing Score and Particle Size of Corn Silage

A single corn hybrid was used to evaluate harvest maturity (Mat) and/or kernel processing (KP) effects on corn silage processing score (CSPS) and particle size (PS). Treatments were arranged in a 2 × 2 factorial of 1) Mat (early and late) and 2) KP (no or yes). A single corn field was planted on April 27, 2020. There were 12 loads (experimental unit) per simple effect treatment mean. Data were analyzed as a completely randomized design. Early harvest occurred on August 28, 2020 [yield (as is) = 39.1 Mg/hectare; DM = 43.1%; CP, NDF, and starch = 6.5, 46.0, and 32.9%, respectively (DM basis)]. Late harvest occurred on September 9, 2020 [yield = 37.8 Mg/hectare (as is); DM = 49.2%; CP, NDF, and starch = 6.6, 49.8, and 37.5%, respectively (DM basis)]. The same equipment was used for both Mat with KP achieved by narrowing processing rollers. The CSPS was determined as the proportion of starch retained below a 4.75-mm sieve. Grain content (DM basis) of the corn silage was calculated from starch/0.72. Particle size was assessed using the Penn State Particle Separator. A Mat × KP interaction (P = 0.05) was detected for CSPS. Early/no and late/no had decreased (P ≤ 0.05) CSPS compared to early/yes and late/yes had the greatest CSPS (P ≤ 0.05) compared to others. Grain content was 13.9% greater in late compared to early (P = 0.01). A Mat × KP interaction (P = 0.03) was detected for PS. Early/no had the greatest (P ≤ 0.05) PS, early/yes and late/no were intermediate, and late/yes had decreased PS compared to others (P ≤ 0.05). These data indicate that Mat and KP influence CSPS synergistically. Producers should consider KP when corn silage is harvested at a later maturity to enhance CSPS.

Air Particle Separator for Unmanned Aerial Vehicles with Combustion Engines

Although a significant portion of unmanned aerial vehicles (UAVs) rely entirely on batteries, there are larger UAVs that operate by utilizing internal combustion engines. These special aircrafts ingest vast quantities of air, directly feeding the supply into the engine for combustion. The goal is to design and build an engine air particle separator (EAPS) for UAVs that employ combustion engines, to remove sand, dust, dirt, or any fine particles from the air being supplied to the engine. Although there are many constraints and restrictions to be considered, it is desired for the EAPS to be a single component, have the ability to connect to a specified intake collar, and fit within a given volume. Among other elements considered, the efficiency, pressure drop, areas of failure, and the selection of a material to build the separator were factored. Three methods of particle filtering were selected: inertial, centrifugal, and hypothetical pressure-barrier separation. To accomplish these goals, the principles of inertia, centrifugal forces, and pressure changes were used along with additive manufacturing – to be able to design and build complex geometries. Results were based on the three prototypes that were built and tested in an enclosure simulating the harsh weather environment and the force applied by the internal combustion engine from the UAV. These results showed that a centrifugal design was best suited for the purpose of the experiment with an experimental efficiency of 87% of the particles being separated from the air.

UTICAJ USITNJENOSTI KOMPLETNOG OBROKA ZA KRAVE U LAKTACIJI NA VREME KONZUMIRANJA I PREŽIVANJA HRANEI HEMIJSKI SASTAV MLEKA

The paper presents research results regarding impact of Total Mixed Ration (TMR)particle sizeon eating time, rumination time, milk yieldand chemical composition for cows in the late lactation (over 150 days). To determine physical form and particle fractions’ ratio of TMR, the Pen State Particle Separator (PSPS) wasused. The cow collars with sensors that respond to sound detection (GEA CowScout Neck) were used to monitorthe eating timeand rumination time.It was determined that different particle fractions’ ratio of TMRhas a significant effect on rumination time (p <0.01),as also on content of milk fat (p <0.01) andprotein (p <0.05).The use of TMR with larger average particle size (6.87 mm) had a positive effect in terms of ruminationtime (400.1 min/day), compared to TMR with a smaller particle size (5.55 mm), where the average rumination timewas (371.1 min/day).Also, the positive effect of TMR with a larger average particle size was reflected in higher milk fat (4.38%) and protein (3.84%) content compared to TMR with a smaller particle size (4.15% and 3.76%, respectively). By providing appropriate physical form of TMR, better rumination time can be achieved along with improving of milk chemical composition.

227 Evaluation of mixer performance in cattle finishing diets of varying physical characteristics

An experiment was conducted to evaluate batch fraction (BF), physical characteristics (DIET), and mixing duration (DUR) on long particle distribution in finishing diets. Diets were mixed in a 2.35 m3 horizontal mixer. The experiment was designed as a 5×3×2 factorial arrangement with nine replications per simple mean. Factors included 1) BF (n = 5), 2) DIET (n = 3) containing no corn-milling by-product (CON), a dry-corn milling by-product [47.45 ± 1.015% DM (as-is basis); DRY], or a wet-corn milling by-product [43.67 ± 1.786% DM (as-is basis); WET], and 3) mixing duration (n = 2) of 20 or 25 revolutions. Diets contained a 1:1 blend of DRC:HMC, the corn-milling by-products replaced the corn blend (20% total diet DM inclusion), grass hay (6% DM inclusion), liquid supplement (5% DM inclusion), and a meal supplement (7% DM inclusion). Data were analyzed as a CRD using the GLIMMIX procedure (SAS Inst., Inc., Cary, NC) using a multinomial approach. Samples of the total mixed ration (TMR) were subjected to separation via the Penn State Particle Separator. The dependent variable of interest was the portion of the TMR retained on the 19 mm sieve. No interactions were detected (P ≥ 0.49). There was an 87.1% (P = 0.01) increase in retention on the 19 mm sieve for last BF compared to the first BF. Diet influenced (P = 0.04) 19 mm sieve retention, there was 10.2% less TMR retained on the 19 mm sieve for DRY versus WET; CON was intermediate. Mixing duration did not influence (P = 0.73) 19 mm sieve retention. These data indicate that as the mixer unloads there can be nearly double the amount of roughage fed; differing physical characteristics of the diet only moderately influence the true roughage content fed. Differing roughage content delivered depending upon the BF could influence daily intake, feed efficiency and alter observed to expected ratios of dietary net energy.

181 Evaluation of mixer performance in cattle finishing diets with 15 or 30 percent dry matter basis inclusion of corn silage

Batch fraction (BF), corn silage inclusion level (DIET), and mixing duration (DUR) were evaluated in an experiment using finishing diets based on corn silage and a blend of dry-rolled (DRC) and high-moisture corn (HMC). A 2.35 m3 horizontal mixer was used to manufacture all diets. The experiment was designed as a 5 x 2 x 2 factorial arrangement with nine replications per simple treatment mean. Factors included: 1) BF (n = 5), 2) DIET (n = 2) containing (DM basis) 15% corn silage or 30% corn silage replacing the corn blend, and 3) DUR (n = 2) of 20 or 25 mixer revolutions. Diets contained corn silage, a 1:1 ratio of DRC:HMC, a liquid supplement (5% DM inclusion), and a meal supplement (7% DM inclusion). Data were analyzed as a completely randomized design using the GLIMMIX procedure of SAS 9.4 (SAS Inst., Inc., Cary, NC) using a multinomial approach. The Penn State Particle Separator was used to separate fractions of the total mixed ration (TMR) with special interest on the portion of the TMR retained on the 19 mm sieve. No interactions between BF, DIET, and REV were detected (P ≥ 0.44). There was a 53.5% increase (P = 0.01) in retention on the 19 mm sieve from the first BF (first 20% of the TMR unloaded from the mixer) compared to the last BF (last 20% of the TMR unloaded from the mixer). The LOW diet had 71.3% decrease (P = 0.01) in retention on the 19 mm sieve (2.13 vs. 7.43 ± 0.220%) compared to the HIGH diet. Increasing DUR from 20 to 25 revolutions had no appreciable influence (P = 0.23) on particles greater than 19 mm. These data indicate that BF fed could alter dry matter intake, dietary net energy content, and influence daily gain. Wednesday, July 22, 2020

Experimental Analysis of a Particle Separator Design With Full-Field Three-Dimensional Measurements

Particle ingestion into turbine engines can cause significant damage through deposition in internal cooling passages. Musgrove et al. proposed a compact particle separator installed between the combustor bypass exit and turbine vane cooling passage inlet. The design had small pressure losses but provided limited particle separation. Its performance has proved difficult to replicate. Borup et al. recently developed a magnetic resonance imaging (MRI)-based technique for full-field, 3D measurements of the mean particle concentration distribution in complex flows. A particle separator based on the Musgrove et al. design was fabricated out of plastic using 3D printing, with the addition of a drain from the collector through which 3% of the total flow was extracted. The separator efficiency was measured at two Reynolds numbers, using water as the working fluid and 33-μm titanium microspheres to represent dust particles. Stokes number was shown to play the dominant role in determining efficiency across studies. MRI was used to obtain the 3D particle volume fraction and three-component velocity fields. The velocity data showed that flow was poorly distributed between the separator louvers, while the collector flow followed the optimal pattern for particle retention. The MRI data revealed that strong swirling flow in the collector centrifuged particles toward the outer wall of the collector and into a partitioned region of quiescent flow, where they proceeded to exit the collector. Future designs could be improved by re-arranging the louvers to produce a more uniform flow distribution, while maintaining the effective collector design.