DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Arguments
The examiner acknowledges that the amended claim set corrects issues noted by the previous office action of (6 – 24 – 2025). All of the previous 112(b) rejections, and drawings objections have been withdrawn.
Applicant's arguments and remarks filed (12 – 24 – 2025) have been fully considered but they are not persuasiveApplicant argues…
Christiansen / Christiansen II does not teach the newly amended feature of controlling a thermal gradient during freezing directs a shape and directionality of an ice structure formed in the slurry, resulting in a porous part having a network of non-uniform pores. Christiansen / Christiansen II merely describes a constant freezing front velocity is desired. "Keeping the solid load and particle size distribution of all suspensions consistent, while ensuring an approximate constant freezing front velocity by implementing a constant temperature change rate during freeze-casting, a structural continuity was maintained across the two materials interface.
Applicant further argues that none of the other applied references make up for the deficiency of Christiansen / Christiansen II as modified.
This is not found to be persuasive because…
As noted below Christiansen discloses in the (Abstract) that in freeze-casting, particulates of a material are suspended in a fluid and a thermal gradient is applied across for directional freezing. Controlling the thermal gradient across the suspension amounts to controlling the kinetics and freezing direction in the suspension and thus the resulting structural features and dimensions of the microchannels. As such, a thermal during freezing is applied to direct a shape and a directionality of an ice structure formed from solidification of the solvent in the slurry. Additionally, (Pg. 2, Introduction, ¶2) teaches that for the constant temperature of the cooling source, the growing solid part of the suspension will act as an increasing thermal resistance, slowing down the freezing front velocity. The constant temperature of the cooling source therefore leads to graded structures of varying pore sizes. As such, sublimation of the solvent and sintering of the ceramic article are understood to transpire after freeze casting, thus removing the solvent from the ceramic article to form a network of non-uniform pores in spaces between the powdered material.
This is unpersuasive because as explained above there was not found to be deficiency in Christiansen / Christiansen II as modified.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
A.) Claim(s) 1, 3 – 5, 7 – 11, 15 & 17 – 20 is/are rejected under 35 U.S.C. 103 as unpatentable over Christiansen et al. (Novel Freeze-Casting Device, 2020, hereinafter Christiansen) in further view of Christiansen et al. (Functionally graded multi-material freeze-cast structures, 2020, hereinafter Christiansen II)Regarding claim 1,
A method of creating a porous part comprising:
forming a slurry by dispersing a powdered material in a solvent;
freezing the slurry in a mold,
controlling a thermal gradient during freezing to direct a shape and
a directionality of an ice structure formed from solidification of the solvent in the slurry,
wherein [[a]]the thermal gradient within the slurry is controlled using at least one of a cooler, a heater, a light emitting device, and an ultrasonic device;
removing the solvent from the slurry to form a network of non-uniform pores in spaces between the powdered material,
wherein the powdered material remains in the mold; and
sintering the powdered material to form the porous part
Christiansen teaches the following:
(Pg. 5, Freeze Casting, ¶2) teaches that ceramic suspension was prepared from 25 vol. % powders of Lanthanum strontium manganite (LCSM / LSMO), CerPoTech in MiliQ water, with the addition of 2.5 wt. %, relative to the ceramic powder a polymeric dispersing agent and at 2.0 wt. %, relative to the ceramic powder a polymeric binder.
(Pg. 5, Freeze Casting, ¶3) teaches that the water or ceramic suspension and mold were pre-cooled in an ice-bath. The mold was then mounted directly onto the cold finger. (Pg. 5, Freeze Casting, ¶4 – 5) teaches that the temperature of the cold finger was kept constant at 275 K for 5–10 min before applying an either linear or exponential freezing profile. The three samples were frozen according to each applied temperature profile. As such, the freezing the slurry in a mold is understood to transpire.
& d.) (Abstract) teaches that in freeze-casting, particulates of a material are suspended in a fluid and a thermal gradient is applied across for directional freezing. Controlling the thermal gradient across the suspension amounts to controlling the kinetics and freezing direction in the suspension and thus the resulting structural features and dimensions of the microchannels. As such, a thermal during freezing is applied to direct a shape and a directionality of an ice structure formed from solidification of the solvent in the slurry.
(Pg. 1, Introduction, ¶1) teaches that freeze-casting, or ice-templating, is a novel templating technique based on the anisotropic growth of ice crystals in aqueous suspensions of a particulate material upon directional freezing. This is achieved by bringing one side of the suspension into contact with cooling source, thus creating a thermal gradient across the suspension. As such, the thermal gradient within the slurry is controlled using at least one of a cooler. (Pg. 2, Fig. 3) shows an arrangement of the freeze caster comprising the cooling source / cold finger.
& h.) (Pg. 8, Freeze-Casting Ceramics, ¶1) Freeze-casting of LCSM suspensions followed by sublimation and sintering results in ceramic structures of directional porosity in the form of well-defined macropores—or microchannels—running parallel to the freezing direction, as illustrated in Fig. 7. (Pg. 5, Freeze Casting, ¶6) teaching that the frozen ceramic freeze-cast samples were subsequently freeze-dried and sintered. (Pg. 2, Introduction, ¶2) teaches that for the constant temperature of the cooling source, the growing solid part of the suspension will act as an increasing thermal resistance, slowing down the freezing front velocity. The constant temperature of the cooling source therefore leads to graded structures of varying pore sizes. As such, sublimation of the solvent and sintering of the ceramic article are understood to transpire after freeze casting, thus removing the solvent from the ceramic article to form a network of non-uniform pores in spaces between the powdered material.
Regarding Claim 1, Christiansen is silent on freeze-drying / removing the solvent from the slurry to form the powdered material while the powdered material remains in the mold. In analogous art for freeze casting ceramic samples with a cold finger and mold arrangement, Christiansen II suggests details regarding freeze-drying / removing the removing the solvent from the slurry while the slurry is still in the mold, and in this regard, Christiansen II teaches the following:
& g.) (Pg. 1400, 2.1 Material Properties and Suspension Preparation, ¶4) teaches that the stock suspensions for freeze-casting, with the addition of 2 wt% binder was poured into the moulds and left to dry for at least 48 h followed by sintering. With (Pg. 1401, 2.2 Freeze Casting, ¶4) teaching that the Ice was removed from the frozen samples in a freeze-drier followed by sintering.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a sample by freeze casting a molded sample with frozen finger of Christiansen. By modifying the freeze-casting process to have its freeze-drying step transpire within the mold, as taught by Christiansen II. Highlighting, one would be motivated to implement a freeze-drying step that transpires within the mold as it provides for freeze-drying and sublimation of the article to remove the solvent, (Pg. 1398, Introduction, ¶2 & Pg. 1400, 2.1 Material Properties and Suspension Preparation, ¶4). Accordingly, the use of known technique to improve similar devices (methods, or products) in the same way and/or the application of a known technique to a known device (method, or product) ready for improvement to yield predictable results provides for the recitation of KSR case law. Wherein, the use of known technique to improve similar devices (methods, or products) in the same way and/or the application of a known technique to a known device (method, or product) ready for improvement to yield predictable results.
Regarding claim 3 as applied to claim 1,
Wherein the thermal gradient is controlled across the entirety of the slurry.
Christiansen teaches the following:
(Pg. 2, Introduction, ¶4) teaches that by controlling the thermal gradient across the suspension amounts to controlling the kinetics, i.e., the freezing front velocity, and freezing direction in the suspension and thus the resulting structural features and dimensions. The thermal gradient partly depends on the temperature of the cooling source but can largely be controlled by the temperature of the cooling source under constant ambient conditions. (Pg. 2, Designing a Freeze-Casting Device, ¶1) teaches that a container that keeps the suspension such that only one side is brought into thermal contact with the cooling source is then mounted on the reservoir. In this way, a thermal gradient is created throughout the suspension, which is also isolated from the ambient. As such, the thermal gradient is controlled across the entirety of the slurry.
Regarding claim 4 as applied to claim 1,
Wherein the thermal gradient is controlled as a function of time.
Christiansen teaches the following:
(Pg. 4, Implementation of Temperature Control, ¶1) teaches thatThe set-temperature can be constant or defined to be a function of time, e.g., a linear function or an exponential function, as has been suggested for obtaining a constant freezing front velocity.
Regarding claim 5 as applied to claim 4,
Wherein a freeze front propagates from a first end of the mold in contact with the cooler to a second end.
Christiansen teaches the following:
(Abstract) teaches that the freezing front was successfully tracked by continuously measuring the temperature gradient along the sample using thermocouples directly mounted on the freeze-casting mold. (Pg. 5, Evaluation of freezing conditions and performance, ¶3) teaches that when looking at the temperature profiles at various thermocouple positions during freezing in (Fig. 4), a significant bump in the temperature curve for the thermocouple at 25.5 mm. As illustrated in (Fig. 4), the table provides a reading of temperature vs time of various thermocouples at different distances, each color representing a different distance. As such, as the free front propagates throughout the mold, the thermocouples at different distances track the movement / appearance of the freeze front propagating from a first end of the mold in contact with the cold finger to a second end of the mold.
Regarding claim 7 as applied to claim 1,
Further comprising:
modifying a thermal boundary condition during freezing
Christiansen teaches the following:
(Pg. 2, Designing a Freeze-Casting Device, ¶3) teaches that bidirectional freezing can be achieved by various mold-altering approaches, e.g., by the introduction of an insulating wedge between the cooling source and the suspension or by using a mold with an additional cooling side perpendicular to the cooling source. Bidirectional freezing imposes a second thermal gradient on the freezing suspension and thus additional ordering of the channel orientations in the plane perpendicular to the freezing direction. (Pg. 4, Implementation of Temperature Control, ¶1) adding that the control software is custom-made in C# and facilitates a PID (proportional–integral–derivative) controller with a feedback loop for controlling the temperature of the cold finger. The cold finger is equipped with a Pt-100 element just inside the vacuum chamber as close as possible to the freezing sample (see Fig. 2(b), (G)). The temperature at this position is continuously fed to the software and adjusted according to the PID settings to fit a given set-temperature. As such, the temperature control is understood to provide for modifying a thermal boundary condition during freezing resulting in a modification of pore orientation of the porous part. Accordingly, due to the control providing for modifying a thermal boundary condition during freezing.The case law for substantially identical process and structure. Where, it has been held that where the claimed and prior art products are identical or substantially identical in structure or are produced by identical or a substantially identical processes, a prima facie case of either anticipation or obviousness will be considered to have been established over functional limitations that stem from the claimed structure. In re Best, 195 USPQ 430, 433 (CCPA 1977), In re Spada, 15 USPQ2d 1655, 1658 (Fed. Cir. 1990). The prima facie case can be rebutted by evidence showing that the prior art products do not necessarily possess the characteristics of the claimed products. In re Best, 195 USPQ 430, 433 (CCPA 1977), MPEP 2144.
Regarding claim 8 as applied to claim 7,
Wherein the directionality is modified to form complex microchannels with constant or changing directionality
Christiansen teaches the following:
(Pg. 2, Introduction, ¶5) teaches that the constant temperature of the cooling source, the growing solid part of the suspension will act as an increasing thermal resistance, slowing down the freezing front velocity. The constant temperature of the cooling source therefore leads to graded structures of varying pore sizes. The pore size has been shown to depend directly on the freezing front velocity with approximately constant freezing front velocities yielding nearly homogeneous channel sizes throughout the freeze-cast structures. (Pg. 4, Implementation of temperature control, ¶1) teaches that the set-temperature can be constant or defined to be a function of time, e.g., a linear function or an exponential function, as has been suggested for obtaining a constant freezing front velocity. (Pg. 8, Freeze-cast ceramics, ¶1) adding that the freeze-casting of LCSM suspensions followed by sublimation and sintering results in ceramic structures of directional porosity in the form of well-defined macropores—or microchannels—running parallel to the freezing direction, as illustrated in Fig. 7. Highlighting, as illustrated in (Fig. 7) the gray areas are ceramic walls, while black voids are micro-channels. As such, as illustrated in (Fig. 7) the channels provided by the freeze-casting process are found to provide a pore orientation that is modified by the constant temperature gradient to form complex microchannels with a constant directionality.
Regarding claim 9 as applied to claim 1,
Wherein a thermal gradient within the slurry is controlled as a function of time as a freeze front propagates through the slurry.
Christiansen teaches the following:
(Pg. 4, Implementation of temperature control, ¶1) teaches that the PID (proportional–integral–derivative) controller with a feedback loop for controlling the temperature of the cold finger. The cold finger is equipped with a Pt-100 element just inside the vacuum chamber as close as possible to the freezing sample (see Fig. 2(b), (G)). The temperature at this position is continuously fed to the software and adjusted according to the PID settings to fit a given set-temperature. The set-temperature can be constant or defined to be a function of time, e.g., a linear function or an exponential function, as has been suggested for obtaining a constant freezing front velocity.
Regarding claim 10 as applied to claim 1,
Wherein a thermal gradient within the slurry is controlled at a boundary of the slurry and the mold.
Christiansen teaches the following:
(Pg. 4, Molds and Temperature Tracking, ¶4) teaches that the mold is equipped with a detachable copper bottom with the primary function of ensuring high thermal conductivity between the freezing sample and the cold finger of the freeze-casting device. As such, the thermal gradient is controlled at a boundary of the slurry and the mold.
Regarding claim 11 as applied to claim 1,
Wherein the porous part has a shape and size similar to a final product.
Christiansen teaches the following:
(Pg. 5, Freeze-casting, ¶6) teaches that the frozen ceramic freeze-cast samples were subsequently freeze-dried for at least 24 h and sintered at 1100 °C in air for 3 h (heating rate of 30 K/h), with initial burnout of organics at 250 °C and 450 °C (heating rate of 15 K/h). Samples were then infiltrated with epoxy and cut into smaller specimens revealing cross sections for imaging using a scanning-electron microscope (SEM, TM3000, Hitachi High-Technologies). Highlighting, that the samples are understood to be prepared are understood to be provided as the item that is very close to the final, or net, shape. Highlighting, the samples are understood to only undergo infiltration with epoxy and cut into smaller specimens as a means for revealing cross sections for imaging. As such, the samples initial prepared prior to revealing cross sections are understood to undergo an initial production of the item that is very close to the final, or net, eliminating the need for finishing methods like machining or grinding. Highlighting, that Christiansen makes no other mention of finishing techniques such as machining, grinding or polishing.
Regarding claim 15 as applied to claim 1,
Wherein the powdered material comprises a ceramic.
Christiansen teaches the following:
(Pg. 5, Freeze-Casting, ¶2) teaches that the ceramic suspension was prepared from 25 vol. % powders of Lanthanum strontium manganite (LCSM / LSMO), (CerPoTech) in MiliQ water, amongst other constituents. As such, the powdered material is understood to comprise a ceramic.
Regarding claim 17 as applied to claim 1,
Wherein the powdered material comprises an atomically thin two-dimensional material having particles with a diameter of 400 nm to 2 µm
Christiansen teaches the following:
(Pg. 5, Freeze-Casting, ¶2) teaches that the suspension was mixed using a low energy ball mill for at least 48 h or until all agglomerates had been eliminated, and a consistent particle size distribution was established as analyzed using a laser diffraction particle size analyzer (LS 13 320, Beckman Coulter), reaching a median particle size of ∼1.8 μm.
Regarding Claim 17, Christiansen is silent on the powdered material comprises an atomically thin two-dimensional material. In analogous art as applied above, Christiansen II suggests details regarding the powdered material comprises an atomically thin two-dimensional material, and in this regard, Christiansen II teaches the following:
(Pg. 1399, Materials and Experimental Procedures, (Fig.1)) teaches that the particle size distribution of suspensions after ball milling reaching median particle sizes of d50 = 0.49 μm and d50 = 0.41 for LCSM9 and LCSM6/ CGO suspensions, respectively. As such, a particle size of 0.49 μm and d50 = 0.41 is found to fall within applicant’s range of 400 nm to 2 μm. Thus, ceramic material with a particle size of 0.49 μm and d50 = 0.41 is understood to be an atomically thin two-dimensional material.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a sample by freeze casting a molded sample with frozen finger of Christiansen. By modifying the freeze-casting composition to include an atomically thin two-dimensional material, as taught by Christiansen II. Highlighting, one would be motivated to implement a atomically thin two-dimensional material as it provides for tailoring the resulting channel sizes and shapes which strongly depend on suspension properties such as particle size, (Pg. 1403, 3.2. Structural Continuity Across Interfaces, ¶5).
Regarding claim 18 as applied to claim 1,
Wherein the powdered material comprises a plurality of materials.
Regarding Claim 18, Christiansen teaches forming a slurry composition comprising a LCSM in s in MiliQ water, (Pg. 5, Freeze Casting, ¶2). Christiansen is silent on the powdered material comprises a plurality of materials. In analogous art as applied above, Christiansen II suggests details the powdered material comprises a plurality of materials, and in this regard, Christiansen II teaches the following:
(Pg. 1400, 2.1 Material Properties and Suspension Preparation, ¶1) teaches that the two stock ceramic suspensions were prepared from 20 vol% powders in MiliQ water: one suspension was prepared solely from LCSM9 (CerPoTech), while the other was prepared from LCSM6 (CerPoTech) and Ce0.9Gd0.1O2 (CGO) (CerPoTech) in weight ratio 9:1, in the following referred to as suspensions/samples LCSM9 and LCSM6/CGO, respectively. As such, powdered material comprise a plurality of materials, namely a mixture of LCSM6/CGO
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a sample by freeze casting a molded sample with frozen finger of Christiansen. By modifying the powdered composition of the freeze-cast sample to comprise a plurality of materials, as taught by Christiansen II. Highlighting, one would be motivated to implement a powdered composition of the freeze-cast sample that comprises a plurality of materials as it provides for tailoring various properties of the sample including the density (Pg. 1400, Materials and experimental procedures, Table 1) and the viscosity, (Pg. 1401, 2.1.1. Viscosity, Fig. 3) and provides for successfully distinguishing the LCSM6 from the LCSM9 from one another during subsequent X-ray (EDS) elemental analysis, (Abstract). Additionally, the use of a known material, in a known environment provides for the recitation of known material in the art case law. Where, the selection of a known material based on its suitability for its intended use supports a prima facie obviousness determination. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945), MPEP 2144.07.
Regarding claim 19 as applied to claim 1,
Wherein the solvent is removed from the slurry via sublimation or evaporation.
Christiansen teaches the following:
(Pg. 8, Freeze-Casting Ceramics, ¶1) Freeze-casting of LCSM suspensions followed by sublimation and sintering results in ceramic structures of directional porosity in the form of well-defined macropores—or microchannels—running parallel to the freezing direction, as illustrated in Fig. 7. (Pg. 5, Freeze Casting, ¶6) teaching that the frozen ceramic freeze-cast samples were subsequently freeze-dried and sintered. As such, sublimation of the solvent and sintering of the ceramic article are understood to transpire after freeze casting, thus removing the solvent from the ceramic article to form a network of pores in spaces between the powdered material.
Regarding claim 20 as applied to claim 1,
Wherein the cooler is placed in at least one of the following locations: at a boundary of the slurry and the mold, at an end of the mold, and within the slurry.
Christiansen teaches the following:
(Pg. 4, Molds and Temperature Tracking, ¶4) teaches that the mold is equipped with a detachable copper bottom with the primary function of ensuring high thermal conductivity between the freezing sample and the cold finger of the freeze-casting device. Highlighting, as shown in (Fig. 3) the bottom of the mold is found to be formed from the copper bottom / the copper bottom forms the bottom portion of the mold. Accordingly, the cold finger is found to be placed at the copper bottom which provides for the cooler being placed at the bottom of the mold.
B.) Claim(s) 3 & 6 – 8, 10, 12 – 13 & 20 is/are rejected under 35 U.S.C. 103 as unpatentable over Christiansen in view of Christiansen II and in further view of Tang et al. (Fabrication of Lamellar Porous…2016, hereinafter Tang)Regarding claim 3 as applied to claim 1,
Wherein the thermal gradient is controlled across the entirety of the slurry.
Christiansen teaches the following:
(Pg. 2, Designing a freeze-casting device, ¶3) teaches that the implementation of an additional cooling source at the opposite side of the freezing suspension, in a so-called double-sided setup, providing for a full thermal control across the sample and thus of the thermal gradient is achieved.
Regarding Claim 3, Christiansen as modified by Christiansen II is silent on the thermal gradient is controlled across the entirety of the slurry. In analogous art to produce a ceramic article by freeze casting, wherein the freeze casting comprises a cold finger as a cooling source, (Abstract), Tang suggests details regarding the thermal gradient is controlled across the entirety of the slurry, and in this regard, Tang teaches the following:
(Abstract) teaches that multiple cold sources with mutually perpendicular directions formed by the bottom and parallel sides of rectangular copper molds induced a specific growth direction for ice crystals. Highlighting, as illustrated on (Pg. 1234) in (Fig. 1) the use of a cold plate in combination with copper plates provides for multiple cold sources from with mutually perpendicular directions.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a sample by freeze casting a molded sample with frozen finger of Christiansen as modified by Christiansen II. By further augmenting the freeze casting apparatus to comprise multiple cold sources, as taught by Tang. Highlighting, one would be motivated to implement multiple cold sources as it provides for improving ice crystal growth direction and consistency and provides for a symmetrical structure of porous ceramics was obtained after applying electrostatic field, (Pg. 1238, Conclusion, ¶1).
Regarding claim 6 as applied to claim 5,
Further comprising:
heating a portion of the slurry separated by a distance from the first end of the mold,
wherein the heated portion of the slurry causes a deviation in a path of the freeze front.
Regarding Claim 6, Christiansen as modified by Christiansen II is silent on heating a portion of the slurry separated by a distance from the first end of the mold. In analogous art as applied above, Tang suggests details regarding heating a portion of the slurry separated by a distance from the first end of the mold, and in this regard, Tang teaches the following:
(Pg. 1234, 3. Results and Discussion) states that the coldest surface should be the bottom cold plate with warmer copper sides because copper needs a longer time to transfer heat. Thus, the growth of ice crystals mainly occurs from the bottom cold plate. As such, the temperature differential caused by the warmer copper provides for heating a portion of the slurry separated by a distance from the first end of the mold.
(Pg. 1234, 3. Results and Discussion) states that the two parallel copper plates limited the direction of lamellar ice crystals to be more aligned from the parallel plates and also accelerated the growth rate of ice crystals. As such, the two parallel copper plates are understood to provide for heated portion causes a deviation in a path of the freeze front, i.e. to be more aligned.
The same rejection rationale, and analysis that was used previously for claim 5, can be applied here and should be referred to for this claim as well.Regarding claim 7 as applied to claim 1,
Further comprising:
modifying a thermal boundary condition during freezing
Christiansen teaches the following:
(Pg. 2, Designing a Freeze-Casting Device, ¶3) teaches that bidirectional freezing can be achieved by various mold-altering approaches, e.g., by the introduction of an insulating wedge between the cooling source and the suspension or by using a mold with an additional cooling side perpendicular to the cooling source. Bidirectional freezing imposes a second thermal gradient on the freezing suspension and thus additional ordering of the channel orientations in the plane perpendicular to the freezing direction. (Pg. 4, Implementation of Temperature Control, ¶1) adding that the control software is custom-made in C# and facilitates a PID (proportional–integral–derivative) controller with a feedback loop for controlling the temperature of the cold finger. The cold finger is equipped with a Pt-100 element just inside the vacuum chamber as close as possible to the freezing sample (see Fig. 2(b), (G)).
Regarding Claim 7, Christiansen as modified by Christiansen II is silent on heating a portion of the slurry separated by a distance from the first end of the mold. In analogous art as applied above, Tang suggests details regarding heating a portion of the slurry separated by a distance from the first end of the mold, and in this regard, Tang teaches the following:
(Pg. 1234, 3. Results and Discussion) states that the coldest surface should be the bottom cold plate with warmer copper sides because copper needs a longer time to transfer heat. Thus, the growth of ice crystals mainly occurs from the bottom cold plate. As such, the temperature differential caused by the warmer copper provides for a modification of a thermal boundary condition during freezing to modify a pore orientation of the porous part.
The same rejection rationale, and analysis that was used previously for claim 5, can be applied here and should be referred to for this claim as well.Regarding claim 8 as applied to claim 7,
Wherein the directionality is modified to form complex microchannels with constant or changing directionality
Christiansen teaches the following:
(Pg. 2, Introduction, ¶5) teaches that the constant temperature of the cooling source, the growing solid part of the suspension will act as an increasing thermal resistance, slowing down the freezing front velocity. The constant temperature of the cooling source therefore leads to graded structures of varying pore sizes. The pore size has been shown to depend directly on the freezing front velocity with approximately constant freezing front velocities yielding nearly homogeneous channel sizes throughout the freeze-cast structures. (Pg. 4, Implementation of temperature control, ¶1) teaches that the set-temperature can be constant or defined to be a function of time, e.g., a linear function or an exponential function, as has been suggested for obtaining a constant freezing front velocity. (Pg. 8, Freeze-cast ceramics, ¶1) adding that the freeze-casting of LCSM suspensions followed by sublimation and sintering results in ceramic structures of directional porosity in the form of well-defined macropores—or microchannels—running parallel to the freezing direction, as illustrated in Fig. 7. Highlighting, as illustrated in (Fig. 7) the gray areas are ceramic walls, while black voids are micro-channels. As such, as illustrated in (Fig. 7) the channels provided by the freeze-casting process are found to provide a pore orientation that is modified by the constant temperature gradient to form complex microchannels with a constant directionality.
Regarding claim 10 as applied to claim 1,
Wherein a thermal gradient within the slurry is controlled at a boundary of the slurry and the mold.
Christiansen teaches the following:
(Pg. 4, Molds and Temperature Tracking, ¶4) teaches that the mold is equipped with a detachable copper bottom with the primary function of ensuring high thermal conductivity between the freezing sample and the cold finger of the freeze-casting device.
Regarding Claim 10, Christiansen as modified by Christiansen II is silent on heating a portion of the slurry separated by a distance from the first end of the mold. In analogous art as applied above, Tang suggests details regarding heating a portion of the slurry separated by a distance from the first end of the mold, and in this regard, Tang teaches the following:
(Pg. 1234, 3. Results and Discussion) states that the coldest surface should be the bottom cold plate with warmer copper sides because copper needs a longer time to transfer heat. Thus, the growth of ice crystals mainly occurs from the bottom cold plate. Highlighting, as illustrated on (Pg. 1234) in (Fig. 1) the use of a cold plate in combination with copper plates provides for multiple cold sources that control a thermal gradient within the slurry, at a boundary of the slurry and the mold.
The same rejection rationale, and analysis that was used previously for claim 5, can be applied here and should be referred to for this claim as well.Regarding claim 12 as applied to claim 1,
Wherein controlling the thermal gradient comprises using bidirectional cooling by cooling a side of the mold and a base of the mold.
Christiansen teaches the following:
(Pg. 2, Designing a Freeze-Casting Device, ¶3) teaches that bidirectional freezing can be achieved by various mold-altering approaches, e.g., by the introduction of an insulating wedge between the cooling source and the suspension or by using a mold with an additional cooling side perpendicular to the cooling source. Bidirectional freezing imposes a second thermal gradient on the freezing suspension and thus additional ordering of the channel orientations in the plane perpendicular to the freezing direction.
Regarding Claim 12, Christiansen as modified by Christiansen II is silent on controlling the thermal boundary comprises using bidirectional cooling by cooling a side of the mold and a base of the mold. In analogous art as applied above, Tang suggests details regarding controlling the thermal boundary comprises using bidirectional cooling by cooling a side of the mold and a base of the mold, and in this regard, Tang teaches the following:
(Pg. 1234, 3. Results and Discussion) states that the coldest surface should be the bottom cold plate with warmer copper sides because copper needs a longer time to transfer heat. Thus, the growth of ice crystals mainly occurs from the bottom cold plate. As such, controlling the thermal boundary comprises using bidirectional cooling by cooling a side of the mold with the copper plates and a base of the mold with the cold plate.
The same rejection rationale, and analysis that was used previously for claim 5, can be applied here and should be referred to for this claim as well.
Regarding claim 13 as applied to claim 12,
Further comprising forming a complex-shaped or concave-shaped freeze front.
Regarding Claim 13, Christiansen teaching that the tracking of the freezing front can be done visually by using a see-through mold made from acrylic glass and equipped with a scale bar, (Pg. 2, Designing a freeze-casting device, ¶4). Christiansen is silent on forming a complex-shaped or concave-shaped freeze front. In analogous art as applied above, Christiansen II suggests details regarding forming a complex-shaped or concave-shaped freeze front, and in this regard, Christiansen II teaches the following:
(Pg. 1402, 3.1 Interface characterization, ¶5) teaches that for immediate tracking of the freezing front is visually. As the freezing front has been found to be a well-defined, slightly concave planer interface perpendicular to the freezing direction. As such, the freeze front is understood to provide for a slightly concave planer interface perpendicular to the freezing direction.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a sample by freeze casting a molded sample with frozen finger of Christiansen. By modifying the freeze-casting process to provide for a freeze front with slightly concave planer interface perpendicular to the freezing direction, as taught by Christiansen II. Highlighting, one would be motivated to implement a freeze front with slightly concave planer interface perpendicular to the freezing direction as it provides for providing a shape / model for the freeze front such that the position of the freezing front is not underestimated during the continuous freezing which results in discontinuous channels across the interface similar to those of stepwise freezing, as the conditions for these samples more closely resembled the latter procedure, (Pg. 1402, Results and discussion, ¶5). Accordingly, the use of known technique to improve similar devices (methods, or products) in the same way and/or the application of a known technique to a known device (method, or product) ready for improvement to yield predictable results provides for the recitation of KSR case law. Wherein, the use of known technique to improve similar devices (methods, or products) in the same way and/or the application of a known technique to a known device (method, or product) ready for improvement to yield predictable results.Regarding claim 20 as applied to claim 1,
Wherein the cooler is placed in at least one of the following locations: at a boundary of the slurry and the mold, at an end of the mold, and within the slurry.
Christiansen teaches the following:
(Pg. 4, Molds and Temperature Tracking, ¶4) teaches that the mold is equipped with a detachable copper bottom with the primary function of ensuring high thermal conductivity between the freezing sample and the cold finger of the freeze-casting device.
Regarding Claim 7, Christiansen as modified by Christiansen II is silent on where the cooler is placed in relation to the slurry and mold. In analogous art as applied above, Tang suggests details regarding the placement of the cooler in relation to the slurry and mold,, and in this regard, Tang teaches the following:
(Pg. 1234, 3. Results and Discussion) states that the coldest surface should be the bottom cold plate with warmer copper sides because copper needs a longer time to transfer heat. Thus, the growth of ice crystals mainly occurs from the bottom cold plate. Highlighting, as illustrated on (Pg. 1234) in (Fig. 1) the use of a cold plate in combination with copper plates provides for multiple cold sources that control a thermal gradient within the slurry, at a boundary of the slurry and the mold.
The same rejection rationale, and analysis that was used previously for claim 5, can be applied here and should be referred to for this claim as well.
C.) Claim(s) 13, is/are rejected under 35 U.S.C. 103 as unpatentable over Christiansen in view of Christiansen II in view of Tang and in further view of Li et al. (Freeze casting of Porous Materials – Review, 2012, hereinafter Li)Regarding claim 13 as applied to claim 12,
Further comprising forming a complex-shaped or concave-shaped freeze front.
Regarding Claim 13, Christiansen as modified by Christiansen II is silent on forming a complex-shaped or concave-shaped freeze front. In analogous art for freeze casting a ceramic article, (Abstract), Li suggests details regarding forming a complex-shaped or concave-shaped freeze front, and in this regard, Li teaches the following:
(Solidification Principals, ¶4) teaches that the breakdown of the solidification front is necessary for the formation of porous structures and often happens because of the instability and supercooling at the interface of the advancing solidification front, the possibility of secondary nucleation and the inhomogeneity of the freezing zone. The curvature at the interface (of the solidification front and the slurry) is dependent on the relative thermal conductivities: i.e., if the particles possess a higher thermal conductivity, the interface is concave; conversely the interface is convex. These interface deviations from a planar surface can further affect the freezing point of the local suspension and alter the supercooling and solidification behavior. As such, the shape of the solidification front being concave or convex is understood to impact the thermal conductivity of the particles and/or the thermal conductivity dispersion medium, and thus the freezing point of the local suspension.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the production method and apparatus for manufacturing a sample by freeze casting a molded sample with frozen finger of Christiansen as modified by Christiansen II. By further augmenting the freeze casting apparatus to form a solidification front that comprise an interface that is concave or convex, as taught by Li. Highlighting, one would be motivated to have a freeze casting apparatus that forms a solidification front that comprise an interface that is concave or convex as it provides for tailoring the thermal conductivity of the particles and/or the thermal conductivity dispersion medium, and thus the freezing point of the local suspension, (Solidification Principals, ¶4). Accordingly, due to the shape of the solidification front impacting various properties of the suspension including the thermal conductivity of the constituents and freezing point suspension, the case law for result effective variable may be recited. Where, it is well settled that determination of optimum values of cause effective variables such as these process parameters is within the skill of one practicing in the art. In re Boesch, 205 USPQ 215 (CCPA 1980). In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977), MPEP 2143 II (B).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Ghosh et al. (US 20220289636 A1) – teaches in the (Abstract) A method and apparatus for forming variable density ceramic structures, where the method includes: obtaining a ceramic powder having an ultrafine particle size; mixing the ceramic powder into a suspension fluid thus forming a ceramic suspension; providing a mold configured to retain the ceramic suspension; providing a plurality of electrodes about the mold;
Bai et al. (US 20170100857 A1) – teaches in the (Abstract) This disclosure provides systems, methods, and apparatus related to freeze casting. In one aspect, a method comprises providing an apparatus. The apparatus comprises a container and a cooling surface. A bottom of the container comprises a wedge. The wedge comprises a first substantially planar surface and a second substantially planar surface with an angle between the first and the second substantially planar surfaces.
Faber et al. (US 20200115291 A1) – teaches in the (Abstract) Provided herein are methods for making a freeze-cast material having a internal structure, the methods comprising steps of: determining the internal structure of the material, the internal structure having a plurality of pores, wherein: each of the plurality of pores has directionality.
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action.
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/Andrés E. Behrens Jr./Examiner, Art Unit 1741
/JaMel M Nelson/Primary Examiner, Art Unit 1743