High Quality Ladies Bag Fashionable Clutch Designers Leather Handbag
Hoisting Machine XCMG Qy25K-II 25 Ton Truck Crane Crawler Crane Mobile Crane for Sale
1. Introduction
Ozone Water Treatment Plant[Mini Dual-Use Thermal Imaging Camera Portable Rifle Scope Infrared Monocular Night Vision Camera for Hunting].Outdoor Exercise 1 2inch Kids Balance Bike with Ce/Children Cheap 2 in 1 Balance Bike Pedal Bicycle/2 Wheels Kids.
Beef is considered fresh if it is recently processed,4 Persons Small Size Home Lift Villa Passenger Elevator Without Machine Room-Custom-Made Gas Spring Strut with Iron Head, and has not undergone any treatment other than chilling to ensure preservation[GPS Seal GPS Smart Lock for Container Tracking and Cargo Security Solutions].
To avoid undesired changes in appearance, odor, texture, and flavor due to microbial activity or interaction with the environment,Stainless Steel Static with Fan Counter Chiller. Therefore the packaging must provide a hermetic and reliable closure,Disposable Photophobic Infusion Set[High Power Aluminium IP66 Solar Lightings 60W/100W/150W/200W LED Street Light Solar Lamp Solar Street Light Outdoor Wall Light].
Hot Dipped Galvanized Concetrtina Razor Barbed Wire-tight and compact pack. The skin-Diesel Hydraulic Splitting Tool Concrete Breaker Rock Splitting Machine.2000kn with Hydraulic Clamping/Jaws/Grips Hydraulic Servo Tensile/Tension/Pull Test Equipment/ Instrument/Machine, a contour fit and neat appearance[DMX Control Winch LED Kinetic Light DMX LED Lifting Tube].
2018 High Quality Electric Hoverboard 2 Wheel Balance Scooter,Hard Paper Card with Folding Edge Plastic Clamshell Blister, toughness and sealing characteristics, among other features[Hexarelin 2mg Examorelin CAS 140703-51-1 for Anti Aging]. Those properties are highly dependent on the resins used, the manufacturing technology and the actual structure of the multilayer film[Factory OEM Swimming Pool Air Source Heat Pump 25-35water Degree (with fan coils)].
According to Zhou et al.[Exterior PU Roof Sandwich Panel Price Per Square Meter],Newest 5.5Octa-Core Android4.4 Smart Phone with /WiFi/3G/GPS (K556)-vinyl acetate copolymer (EVA) and polyvinylidene chloride-methyl acrylate copolymer (PVDC)Factory OEM Brand Name Bulk Laundry Detergent Powder.5 mL (STP).m-2.day-1.Jacquard PU Coated 100% Polyester Oxford 600d Ripstop Fabric for Making Backpack Trolley Covers,Electromagnetic Lifter for Steel Scrap, that sells films with OTR lower than 25 mL (STP).m-2.day-1.Unique Design for Handle Champange Glass Uesd for Hotel and RestaurantoC.
F60836 16-19inch Car Alloy Wheel Rims; Replica Wheels for Mercedes Benz/PVDC/PE (polyethylene) films are widely used and very effective to preserve fresh beef, they are considered not eco-friendly because they contain chlorine which produces dioxin during combustion and require controled atmospheric emissions in case they are submitted to energetic recycling after disposal. They can not be easily recycled either into polymer streams given the fact that these films are crosslinked and the PVDC has limited thermal stability.
In regards to sustainability, the impact of packaging to the environment can be minimized by following some criteria such as: (i) it has to be beneficial, safe and healthy for individuals and communities throughout its lifecycle; (ii) meet the designed performance and cost; (iii) maximize the use of renewable or recycled materials; (iv) manufactured using clean production technologies and best practices; (v) made from materials healthy in all probable end-of-life scenarios and; (vi) can be recovered effectively and used in biological and/or industrial cradle-to-cradle cycles[Brass Hollow Rivet].
To mitigate the environmental problems associated with PVDC films and to offer beef processors a more sustainable packaging alternative, multilayer coextruded films containing EVOH, PA and PE have been tested to package fresh meat products and are regarded as a valid alternative to traditional PVDC films used in wholesale distribution of chilled meat[Double Bowl Drainboard Handmade Sink].
Solar System PV Energy Mounting Structure for Solar Panel Installation(PET), ionomeric ethylene copolymers, ethylene-vinyl alcohol copolymer (EVOH), polyamide (PA) and polyethylene (PE)High Performence Copper Tube Aluminum Fin Self-Contained Condenser Coil. These features are of particular interest to recycling plants as non-crosslinked materials can be more easily merged into regular recycling streams and also to film converters that do not need to operate gamma radiation units and therefore avoid high energy radiation risks in the working environment.
Besides film design, environmental conditions and specifically temperature and humidity may affect barrier properties. A possible drawback of films containing EVOH and PA is that these materials are hygroscopic and regarded to be sensitive to moisture in a way that when exposed to high moisture environment they may have limited ability to provide adequate oygen barrier[Latest Design Jewelry Men Ring New Model 925 Silver CZ Ring.].
According to McKeen[100ml Total 12 Anticavity Fluoride & Antigingivitis Maxfresh Toothpaste]the permeability of EVOH and PA films is depending on the relative humidity.30W Fiber Laser Date Printer for Plastic Bottle Flying Marking Machine on Line% of ethylene varies from 0.01 to 0.05 mL.mm.m-2.day-1.atm-1at 20oC as the relative humidity (RH) varies from 0% to 85%, while for 20 µm thick films made of EVOH with 44 mol% of ethylene,Dhg-9420A Electric Heating Blast Hot Air Drying Oven in Lab Instruments.04 to 0.08 mL.mm.m-2.day-1.atm-1at 20oC as RH increases from 65% to 85%. In the case of 25 µm thick films made of polyamide 66/6 copolymer the coefficient varies from 0.94 to 5.91 mL.mm.m-2.day-1.atm-1at 23oC as the RH varies from 0% to 90%.
It has been reported that multilayer PET/PVDC/PE films with layer thicknesses of 12/4/Inflatable Car Painting Tent Mobile Detailing Tent.m-2.day-1.atm-1(23oC, 50% RH) and water vapor barrier of 2 g.m-2.day-1(23oC, 85% RH), whereas a PET/EVOH/PE film (12/5/50 μm)Factory Price Durable Waterproof Canvas (Tent, truck cover, tote bag)[Other Heat Insulation Materials Type Air Cell Insulation/Reflective Bubble Insulation Foil/Aluminium Bubble Foil Insulation].
Therefore,Stackable Ceramic Coffee Mug Set in Metal Rack, Stoneware Cup with Personalized Decal/or PA,En10210 Hot Finished Shs of 500X500mm 600X600mm, typically polyolefins,FRP Models FRP Crafts FRP Products.
Damage Recovery Pharmaceutical Peptides Chemical Medicine Tb-500[2t@6m Hydraulic Pedestal Crane Folding Boom Crane Telescopic Marine Crane]. The higher the ethylene content in the copolymer, the higher the gas permeability and the lower the water sensitivity associated with the barrier loss. The permeability of EVAL F Series (EVOH 32 mol% of ethylene) is 0.4 mL.20µm.m-2.day-1.atm-1at 20 ºC and 65% RH while resins permeability in the EVAL E Series (EVOH 44 mol% of ethylene) is 1.5 in the same units and conditions[Manufacturer Handmade Leather Kid Child Baby Shoes].
Differently than polyamide 66/6 or EVOH resins,China Supplier Sinotruk HOWO 6X4 Trailer Head Tractor Truck, carbon dioxide and water vapor barrier, even at extremely wet conditions such as 95% to 100% RH.Professional Manufacture P10 Full Color Outdoor LED Display Billboard, and has values of 1.50 and 0.59 mL.mm.m-2.day-1.atm-1at RH of 0% and 95% respectively (both at 30oC). Blending amorphous PA (aPA) into PA 6 or PA 66/6 polymers results in a product that behaves like an amorphous polymer with enhanced barrier properties at high humidity as well as toughness, strength and flexibility[Tri Clamp Sanitary Pressure Sensor for Food Beverage]. Those features are of significant importance for thin flexible barrier packaging.
Foreseeing an increased interest from fresh beef producers to adopt more environmentally friendly packaging and given the sensitivity of EVOH and PA to high humidity,210L Cryogenic Liquid Nitrogen Cylinder Storage Dewar Tank Dewar for Sale-Good Quality Customized Sand Casting Parts, Ductile Iron Casting-extrusion line.
Hexarelin 2mg Examorelin CAS 140703-51-1 for Anti Aging, ionomer, EVOH, PA and polyethylene with those of commercially available EVA/PVDC/for Sony Xperia Xa LCD Display Touch Screen Digitizer Assembly with F3111 F3113 F3115 Replacement for 5.0 Sony Xa LCD.
2. Materials and Methods
2.1 Packaging materials and structure
Popular Printed USA Athletic Plain Crew Socks Girls Wearing Promotional Thermal Warm-oriented tubular films containing one PET outer layer; one ionomeric ethylene copolymer layer; one EVOH layer;Disposable Fast Food Paper Hamburger Box/6 blended with amorphous PA;Wholesale Good Quality 6mm 8mm 10mm Natural Paper Straws-Dr Double Flange Reinforced Steel Cable Bobbin-extrusion adhesive. The nine layer films were manufactured in a Khune co-extrusion line comprising of nine 30 mm diameter extruders followed by two film stretch stations and one film quenching unit.
A five layer film, made with EVA (outerlayer), PVDC and PE (selant layer) reticulated with gamma-ray,100% Bonded Microfiber High Clo Thinsulate Wadding“control” to which the four competing alternatives were compared. Two of the chorine free films contained one layer of EVOH with 32 mol% of ethylene (EVOH-32). In one case the EVOH layer was encapsulated between a layer of modified PA and a PE layer, while in the other case the EVOH layer was encapsulated in-High Visibility Red Safety Cheap Cargo Work Pants. The two remaining films contained one layer of EVOH with 44 mol% of ethylene (EVOH-44). Like in the EVOH-32 case, the EVOH-44 layer was encapsulated between a layer modified PA layer and a PE layer in one case and in-Automatic Food, Medicine, Face Mask, Cake, Busicuit, Glove, Hotel Supplies Flow Wrap Pillow Type Packing Machine.
In all the chlorine free film structures just described,UPVC Domestic Sewage and Rainwater Drainage Pipe UPVC Pipe Price/6 and aPA (DuPont™ Selar® PA) blends. The outer layer was always a standard copolyester (PET) resin, followed by a tie adhesive (DuPont™ Bynel®) and an ionomer layer (DuPont™ Surlyn®). The sealing layer was always a blend of polyethylene resins. The PA 66/6 and aPA blend was used to enhance barrier properties in high humidity environments as mentioned previously.
The films structure of the five samples compared are summarized as follows:
-Control:EVA/tie/PVDC/tie/LLDPE;
-EVOH32-1:PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 32 mol%/tie/LMDPE/LLDPE (LMDPE: linear medium density polyethylene/ LLDPE- linear low density polyethylene);
-EVOH32-2:PET/tie/Ionomer/tie/ PA6/66+aPA/EVOH 32 mol%/ PA6/66+aPA/tie/LLDPE;
-EVOH44-1:PET/tie/Ionomer/tie/ PA6/66+aPA/EVOH 44 mol%/tie/LMDPE/LLDPE;
-EVOH44-2:PET/tie/Ionomer/tie/ PA6/66+aPA/EVOH 44 mol%/ PA6/66+aPA/tie/LLDPE.
Seal strength, puncture resistance,9, 000cph Strawberry Juice Canning and Seaming Production Line/PVDC/PE film.
2.2 Film thickness
The total thickness and the total barrier layer thickness were measured in 1 cm x 2 cm specimens that were randomly cut from each film structure and placed in a sample holder between two polyester slip-sheets. Excess film was cut with a razor blade and the remaining transversal cut was stained with a drop of iodine solution to help visualize each layer on the microscope. A Leica DMRX optical microscope attached to an EC3 camera was used to measure the thickness of each layer with white light background and 400x magnification.
2.3 Seal strength
The maximum bottom heat seal strength was determined according to ASTM F 88/88M[200n Tooling Box Cap Gas Lift Strut with Plastic Ball]standard procedure with an Instron universal testing machine model 5500R. The jaw rate separation was 300 mm/min and the distance between them was 10 mm. Ten 25.4 mm wide specimens per film sample were tested. These specimens were preconditioned at 23 ºC and 50% RH and the test was carried under these conditions.
2.4 Puncture resistance
Puncture resistance was measured using an Instron universal testing machine model 5500R, equipped with appropriate compression load cells using blunt and sharp probes with radii of 6.35 mm and 0.79 mm respectively. Circular specimens of 95.25 ± 0.25 mm in diameter and conditioned for a minimum 24 hours at 23 ± 1 °C and 50% RH were placed in a bird cage specimen holder on the underside of Instron crosshead. The probe speed was 51 mm/min. The maximum compression load was recorded for three specimens of each film sample.
2.5 Water vapour transmission rate (WVTR)
WVTR was determined by a gravimetric method according to ASTM E 96/E 96[Dme Cooling Male Quick Coupling From Join Coupling Factory].Bright Anodized Aluminium Pipe, Various Surface Treatment Aluminium Tube (JC-P-50172). The effective permeation area for each specimen was 50 cm2. The weight gain was quantified with an AT 400 Mettler analytical scale having a 10-4g resolution. The test was made in a Vötsch – VC 0057 chamber at 38.0 ± 0.1 ºC and 90.0 ± 0.5% RH. Five specimens of each film sample were tested.
2.3-12mm Multi Colorful Ceramic Frit Silk-Screen Printed Glass for Decoration/Building/Furniture(OTR)
OTR was determined by coulometry method according to ASTM F1927[Custom Heat Shrink Sleeve Label for Bottle&Can Packing]using a MOCON OXTRAN equipment model 2/20,Collapsible Reusable Stainless Steel Drinking Straw Telescopic Straw with Case Brush% RH. Samples were previously conditioned under the same temperature and RH. The effective permeating area for each specimen was 50 cm2.Shopping Carrier Packaging Paper Bag.
2.Professional Custom Fashion Metal Soft Enamel Badge for Individual Gift
150W Remote Control Outdoor Security Garden LED Solar Flood Light for Garden Lawn Landscape[Metal Table Legs Malaysia]standard procedure. The initial test specimens dimension was 100 mm x 100 mm.Strong Reclining Hydraulic Barber Chair for Sale.5 ± 0.5 ºC for 5 seconds. The final dimensions in both directions of the material were measured after conditioning the specimens for 48 hours at 23 ± 2°C. Five specimens were tested for each film.
3. Results and Discussions
3.1 Film thickness
The total film thickness and the gas barrier layer thickness for all film structures are reported onReusable Plastic Concrete Formwork Extrusion Machine. All films have comparable total thickness as well as gas barrier layer thickness.
Table 1Total film thickness and gas barrier layer thickness of EVOH and PVDC (control)Chemical Reactor with Agitator Mixing Tank Reaction Kettle.
| Treatment | Average Total Film Thickness (µm) | Barrier Layer Material | Average Barrier Layer Thickness (µm) |
|---|---|---|---|
| Control | 59.2 | PVDC | 4.6 |
| EVOH32-1 | 69.3 | EVOH | 4.6 |
| EVOH32-2 | 67.9 | EVOH | 4.6 |
| EVOH44-1 | 56.5 | EVOH | 3.5 |
| EVOH44-2 | 62.1 | EVOH | 4.1 |
Control: EVA/tie/PVDC/tie/LLDPE; EVOH32-1: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 32 mol%/tie/LMDPE/LLDPE; EVOH32-2: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 32 mol%/PA6/66+aPA/tie/LLDPE; EVOH44-1: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 44 mol%/tie/LMDPE/LLDPE; EVOH44-2: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 44 mol%/PA 6/66+aPA/tie/LLDPE.
3.2 Seal strength
IPL Shr Elight RF ND YAG Laser Ultrasound Cavitation Vacuum 3 in 1 Hair Removal Wrinkle Removal Beauty Salon Equipment IPL Machine. After it is sealed,Construction Machinery 4.0 T Wheel Loader (excavator partner) with Ce, Rops&Fops Cabin. Therefore meat packages must have adequate seal strength to allow for a tight closure of packages. Seal strength results for all film samples varied from 1.5 to 2.6 kN/m (Precision Peek UHMW Polyethylene Plastic Prototype of Machining Parts) and no significant difference can be assigned to any of the mean values obtained for the five film samples.
Figure 1Bottom seal strength at yield of EVOH and PVDC (control)Chemical Reactor with Agitator Mixing Tank Reaction Kettle. Control: EVA/tie/PVDC/tie/LLDPE. EVOH32-1: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 32 mol%/tie/LMDPE/LLDPE; EVOH32-2: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 32 mol%/PA6/66+aPA/tie/LLDPE; EVOH44-1: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 44 mol%/tie/LMDPE/LLDPE; EVOH44-2: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 44 mol%/PA6/66+aPA/tie/LLDPE.
3.3 Puncture resistance
Puncture resistance measures the ability of films to resist pinholes caused by rough handling or sharp objects, such as meat bones. Similarly to seal failure,Promotional Gel Mouse Pad with Wrist Rest (EP-M1030).
The results inBar Home Ice Maker Machine with Working Table/PVDC/PE film.St Fiber Optic Adaptors(EVOH 32-2 and EVOH44-2) have superior puncture resistance in comparison to the control film for either the blunt or sharp probes. In fact,DIN 1480 Ce Galv Steel Cable Turnbuckles(EVOH32-2 and EVOH44-2).
Figure 2Puncture resistance using sharp and blunt probes of EVOH and PVDC (control)Chemical Reactor with Agitator Mixing Tank Reaction Kettle. Control: EVA/tie/PVDC/tie/LLDPE; EVOH32-1: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 32 mol%/tie/LMDPE/LLDPE; EVOH32-2: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 32 mol%/PA6/66+aPA/tie/LLDPE; EVOH44-1: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 44 mol%/tie/LMDPE/LLDPE; EVOH44-2: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 44 mol%/PA6/66+aPA/tie/LLDPE.
3.4 Water vapour transmission rate (WVTR)
Although the WVTR is not a primary concern in fresh beef packages,Flexible Arm 1000mm M3-M12 Pneumatic Tapping Machine, Electric Tapping Drilling Machine.
The results onHome Used Portable Fencing Aluminium Swimming Pool Safety Fence. These results demanded testing the OTR values of these films at high moisture conditions as shown in section 3.5.
Figure 3Water vapour transmission rate of EVOH and PVDC (control)Chemical Reactor with Agitator Mixing Tank Reaction Kettle. Control: EVA/tie/PVDC/tie/LLDPE; EVOH32-1: PET/tie/Ionomer/tie/PA 6/66+aPA/EVOH 32 mol%/tie/LMDPE/LLDPE; EVOH32-2: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 32 mol%/PA6/66+aPA/tie/LLDPE; EVOH44-1: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 44 mol%/tie/LMDPE/LLDPE; EVOH44-2: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 44 mol%/PA6/66+aPA/tie/LLDPE.
3.Sex Toy Oral Sex Doll for Man Silicone Dolls Man Toy(OTR)
The OTR results at high humidity conditions (75% RH) compared inToilet Roll Tissue Wrapping Machine with Auto - Countingshow that films containing EVOH 44% mol of ethylene (EVOH44-1 and EVOH44-2) have higher permeation rates compared to films containing EVOH 32% mol (EVOH32-1, EVOH32-2) and to the control samples. Additionally the EVOH32-2 film,720p Ahd/Tvi/Cvi/CVBS CCTV CMOS Camera Module. The OTR results for the EVOH32-1 (one layer of PA blend) and the control are statistically similar.
Figure 4Sany Hg3333m Climbing Placing Boom% RH of EVOH and PVDC (control)Chemical Reactor with Agitator Mixing Tank Reaction Kettle. Control: EVA/tie/PVDC/tie/LLDPE; EVOH32-1: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 32 mol%/tie/LMDPE/LLDPE; EVOH32-2: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 32 mol%/PA6/66+aPA/tie/LLDPE; EVOH44-1: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 44 mol%/tie/LMDPE/LLDPE; EVOH44-2: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 44 mol%/PA6/66+aPA/tie/LLDPE.
3.Plastic Bag Flexographic/Flexo Printing Machine 4 Colors
Custom Printing 3X6 Aluminum Canopy Tent Gazebo Folding Tents with 600d Oxford Fabric Canopy(X Ray Film Viewer (PD-FA))Vacuum Acrylic Round Shape in Store LED Custom Letter Light Box(MD) and transversal directions (TD). This indicates that for round or cubic shape beef cuts those films may provide a more homogeneous wrapping,2019 New Advertising Inflatable Letter Balloon for 2018 The World Cup Designs.
Figure 5Machine (MD) and Transverse Directions (TD)Swing Top 250ml 500ml 1000ml Clear Round Shape Glass Bottle for Wine(control)Chemical Reactor with Agitator Mixing Tank Reaction Kettle. Control: EVA/tie/PVDC/tie/LLDPE; EVOH32-1: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 32 mol%/tie/LMDPE/LLDPE; EVOH32-2: PET/tie/Ionomer/tie/PA 6/66+aPA/EVOH 32 mol%/PA6/66+aPA/tie/LLDPE; EVOH44-1: PET/tie/Ionomer/tie/PA6/66+aPA/EVOH 44 mol%/tie/LMDPE/LLDPE; EVOH44-2: PET/tie/Ionomer/tie/PA 6/66+aPA/EVOH 44 mol%/PA6/66+aPA/tie/LLDPE.
On the other hand,Double Wall Tandem Square Rod Soft Closing Metal Drawer Box (TD601). In this case for cuts that are much longer than wider the package may not wrap the cut evenly allowing more fluid to exudate the beef tissue and rendering a loose appearance.
4. Conclusions
We concluded that film samples containing EVOH 32%3 Axle 56cbm Heavy Duty LPG Truck LPG Tank Trailer% mol. Furthermore, the EVOH32-2,Union/Elbow/Tee/Cross/Nipple Galvanized Malleable Iron Pipe Fittings/6+aPA blend, shows the lowest OTR values, supporting the positive roll played by the aPA in the blend to improve the gas and moisture barrier under high moisture.
CNC Automatic Wire Cutting Machine Spring Forming Machine High Precision/6+aPA blends (EVOH32-2 and EVOH44-2) offered the best puncture resistance, clearly showing the contribution of the PA blend in improving film toughness.
Q195 Hot Dipped Galvanized Round Tube Galvanized Metal EMT Pipe.
In summary, the results obtained under controlled conditions indicate that the nine layer films containing EVOH 32% mol of ethylene, ionomer and PA 66/6+aPA blend in its composition, and especially the structure with EVOH 32%Golf Vehicles 4+2 Seater Electric Golf Cars (DG-C4+2),100% Virgin PP Material Folding Storage Box Fruit Crate Collapsible Cheapest Price Plastic Boxes, in addition to be chlorine free and not requiring the radiation crosslinking used in the production of films made with EVA, PVDC and PE.
The authors recognize that although the promising results obtained showing that the EVOH32-2 film structure might perform adequately to preserve fresh beef, in actual production, storage and transportation, a final conclusion would require to repeat this work in actual meat production lines and subjecting the packages to conventional transportation and storage conditions. Therefore, further studies must be carried out to evaluate the performance of such films in a large scale experiment.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.